Effects of relay rounds on idea generation of 3-person-subgroup： An experimental study

IntroductionThe Kerr effect, also known as the magneto-optic Kerr effect (MOKE), is a phenomenon that manifests the interaction between light and magnetic fields in a material. It is named after its discoverer, John Kerr, who observed this effect in 1877. The radial Kerr effect, specifically, refers to the variation in polarization state of light upon reflection from a magnetized surface, where the change occurs radially with respect to the magnetization direction. This unique aspect of the Kerr effect has significant implications in various scientific disciplines, including condensed matter physics, materials science, and optoelectronics. This paper presents a comprehensive, multifaceted analysis of the radial Kerr effect, delving into its underlying principles, experimental techniques, applications, and ongoing research directions.I. Theoretical Foundations of the Radial Kerr EffectA. Basic PrinciplesThe radial Kerr effect arises due to the anisotropic nature of the refractive index of a ferromagnetic or ferrimagnetic material when subjected to an external magnetic field. When linearly polarized light impinges on such a magnetized surface, the reflected beam experiences a change in its polarization state, which is characterized by a rotation of the plane of polarization and/or a change in ellipticity. This alteration is radially dependent on the orientation of the magnetization vector relative to the incident light's plane of incidence. The radial Kerr effect is fundamentally governed by the Faraday-Kerr law, which describes the relationship between the change in polarization angle (ΔθK) and the applied magnetic field (H):ΔθK = nHKVwhere n is the sample's refractive index, H is the magnetic field strength, K is the Kerr constant, and V is the Verdet constant, which depends on the wavelength of the incident light and the magnetic properties of the material.B. Microscopic MechanismsAt the microscopic level, the radial Kerr effect can be attributed to twoprimary mechanisms: the spin-orbit interaction and the exchange interaction. The spin-orbit interaction arises from the coupling between the electron's spin and its orbital motion in the presence of an electric field gradient, leading to a magnetic-field-dependent modification of the electron density distribution and, consequently, the refractive index. The exchange interaction, on the other hand, influences the Kerr effect through its role in determining the magnetic structure and the alignment of magnetic moments within the material.C. Material DependenceThe magnitude and sign of the radial Kerr effect are highly dependent on the magnetic and optical properties of the material under investigation. Ferromagnetic and ferrimagnetic materials generally exhibit larger Kerr rotations due to their strong net magnetization. Additionally, the effect is sensitive to factors such as crystal structure, chemical composition, and doping levels, making it a valuable tool for studying the magnetic and electronic structure of complex materials.II. Experimental Techniques for Measuring the Radial Kerr EffectA. MOKE SetupA typical MOKE setup consists of a light source, polarizers, a magnetized sample, and a detector. In the case of radial Kerr measurements, the sample is usually magnetized along a radial direction, and the incident light is either p-polarized (electric field parallel to the plane of incidence) or s-polarized (electric field perpendicular to the plane of incidence). By monitoring the change in the polarization state of the reflected light as a function of the applied magnetic field, the radial Kerr effect can be quantified.B. Advanced MOKE TechniquesSeveral advanced MOKE techniques have been developed to enhance the sensitivity and specificity of radial Kerr effect measurements. These include polar MOKE, longitudinal MOKE, and polarizing neutron reflectometry, each tailored to probe different aspects of the magnetic structure and dynamics. Moreover, time-resolved MOKE setups enable the study of ultrafast magneticphenomena, such as spin dynamics and all-optical switching, by employing pulsed laser sources and high-speed detection systems.III. Applications of the Radial Kerr EffectA. Magnetic Domain Imaging and CharacterizationThe radial Kerr effect plays a crucial role in visualizing and analyzing magnetic domains in ferromagnetic and ferrimagnetic materials. By raster-scanning a focused laser beam over the sample surface while monitoring the Kerr signal, high-resolution maps of domain patterns, domain wall structures, and magnetic domain evolution can be obtained. This information is vital for understanding the fundamental mechanisms governing magnetic behavior and optimizing the performance of magnetic devices.B. Magnetometry and SensingDue to its sensitivity to both the magnitude and direction of the magnetic field, the radial Kerr effect finds applications in magnetometry and sensing technologies. MOKE-based sensors offer high spatial resolution, non-destructive testing capabilities, and compatibility with various sample geometries, making them suitable for applications ranging from magnetic storage media characterization to biomedical imaging.C. Spintronics and MagnonicsThe radial Kerr effect is instrumental in investigating spintronic and magnonic phenomena, where the manipulation and control of spin degrees of freedom in solids are exploited for novel device concepts. For instance, it can be used to study spin-wave propagation, spin-transfer torque effects, and all-optical magnetic switching, which are key elements in the development of spintronic memory, logic devices, and magnonic circuits.IV. Current Research Directions and Future PerspectivesA. Advanced Materials and NanostructuresOngoing research in the field focuses on exploring the radial Kerr effect in novel magnetic materials, such as multiferroics, topological magnets, and magnetic thin films and nanostructures. These studies aim to uncover newmagnetooptical phenomena, understand the interplay between magnetic, electric, and structural order parameters, and develop materials with tailored Kerr responses for next-generation optoelectronic and spintronic applications.B. Ultrafast Magnetism and Spin DynamicsThe advent of femtosecond laser technology has enabled researchers to investigate the radial Kerr effect on ultrafast timescales, revealing fascinating insights into the fundamental processes governing magnetic relaxation, spin precession, and all-optical manipulation of magnetic order. Future work in this area promises to deepen our understanding of ultrafast magnetism and pave the way for the development of ultrafast magnetic switches and memories.C. Quantum Information ProcessingRecent studies have demonstrated the potential of the radial Kerr effect in quantum information processing applications. For example, the manipulation of single spins in solid-state systems using the radial Kerr effect could lead to the realization of scalable, robust quantum bits (qubits) and quantum communication protocols. Further exploration in this direction may open up new avenues for quantum computing and cryptography.ConclusionThe radial Kerr effect, a manifestation of the intricate interplay between light and magnetism, offers a powerful and versatile platform for probing the magnetic properties and dynamics of materials. Its profound impact on various scientific disciplines, coupled with ongoing advancements in experimental techniques and materials engineering, underscores the continued importance of this phenomenon in shaping our understanding of magnetism and driving technological innovations in optoelectronics, spintronics, and quantum information processing. As research in these fields progresses, the radial Kerr effect will undoubtedly continue to serve as a cornerstone for unraveling the mysteries of magnetic materials and harnessing their potential for transformative technologies.。

查询密码：0323特质偏度是否被定价？*郑振龙王路跖（厦门大学金融系，厦门361005）作者简介：郑振龙（1966-），男，汉族，籍贯福建，金融学博士，国务院学科评议组成员，国务院政府特殊津贴专家，厦门大学闽江学者教授、博导，美国加州大学洛杉矶分校富布莱特学者，英国伦敦经济学院高级研究学者，《金融学季刊》主编。

研究方向为资产定价、金融工程和风险管理。

电话：139****8903Email:***************.cn。

通讯地址：厦门大学金融系，361005王路跖(1986-)，男，汉族，籍贯浙江，厦门大学金融工程硕士，研究方向为资产定价和金融工程。

电话：186****6762Email:***************。

通讯地址：厦门大学金融系，361005*基金项目：国家自然科学基金面上项目：非完美信息下基于观点偏差调整的资产定价，项目号：70971114；国家自然科学基金青年项目：投资者风险偏好：度量与应用，项目号：71101121；教育部人文社科一般项目（07JA790077）；教育部留学回国人员科研启动基金“人民币即期与远期汇率关系及外汇市场协同稳定机制研究”（教外司留[2008] 890）。

特质偏度是否被定价？内容提要：本文主要研究了我国A股市场上特质偏度和预期收益率的关系。

结合中国市场的实际，本文采用横截面回归的方法提取预期特质偏度，随后运用Fama-Macbeth方法来验证预期收益率和预期特质偏度之间的关系。

实证结果表明二者之间存在显著的负向关系，在控制了流动性因子、协偏度和协峰度等变量的影响之后该结论仍然成立。

同时，本文还对“特质波动率之谜”进行了重新检验，我们发现在控制了预期特质偏度之后，滞后的特质波动率与预期收益率之间的负相关关系不再显著，从而证实了预期特质偏度中含有一部分特质波动率的信息。

最后，在区分了大、小公司的子样本中进行的稳健性检验也支持上述结论。

关键词：预期特质偏度特质偏度风险特质波动率之谜一、引言自从Sharpe(1964)和Lintner(1965)独立推导出资本资产定价模型(CAPM)后，大部分对于投资组合的分析基本上都是在均值—方差分析的跨架下进行。

作者简介:胡龙青(1971 ),女,安徽桐城人,上海电力学院直属外语系讲师。

山西师大学报(社会科学版)研究生论文专刊第34卷 2007年6月论法律英语的语言特点胡龙青摘 要:法律英语作为一种具有规约性的语言的分支,有其独特的语言风格特点。

本文通过大量的例句从词汇、专业用语、句法等方面讨论了法律英语独特的语言特点,以促进法律英语的学习、法律文书合同的理解、法律英语翻译研究。

关键词:法律英语;语言特点;词汇;句法法律英语,在英语国家中被称为L egal Language 或L an -guage o f theL a w,即法律语言,在英语中指表述法律科学概念以及诉讼或非诉讼法律事务时所用的语种或某一语种的部分用语。

法律英语作为一种具有规约性的语言的分支,有其独特的语言风格特点,它在词汇句法、专业用语以及表达方式等方面有别于普通英语,而其中最重要、最本质的特点就是用词准确。

法律英语用词要求高度准确,这与法律工作的特点有直接的关系。

立法语言所表述的内容是全体公民的行为规范,是人们的行为准则,同时也是司法人员的执法依据。

因此,立法者要通过语言文字的准确运用来表述国家的立法思想和具体的法律内容,以便司法人员和全体公民能清楚地了解作为一个国家的公民,他们拥有哪些权利和义务,从而明白哪些行为是被允许的,哪些行为是被禁止的,哪些行为是要受到鼓励或制裁的,以及一旦出现违法行为会产生什么样的后果及其应负什么样的法律责任。

一、词汇特点1 法律英语用词庄重、规范、书面语较多。

法律是掌握国家政权的阶级、集团的意志体现,它有鲜明的政策性,权威性。

为了维护法律的严肃性,法律、法规遣词造句力求准确,用词正式,语意严谨。

不像文学作品那样,有华丽的词藻和丰富的修饰语,也不可能使用比喻,夸张和委婉语气。

如:T h i s l aw is pro m ulgated w it h t he purpose of regu l a ti ng i nsurance acti v iti es ,pro tecti ng t he leg iti m a te ri ghts and i nterests o f the pa r -ti es i nvo l v ed ,streng t heni ng supe rv isi on and regu l ation o f t he i n -s urance i ndustry and pro m oti ng its healthy deve l op m ent .(为了规范保险活动,保护保险活动当事人的合法权益,加强对保险业的监督管理,促进保险事业的健康发展,制定本法)2 准确用词与模糊语言的同时出现法律语言,尤其是立法语言常把准确性与模糊性这一矛盾纳入同一法律规范。

Eur.Phys.J.B1,327–331(1998)Effect of surface electricfield on the anchoringof nematic liquid crystalsG.Barbero1,a,L.R.Evangelista2,and N.V Madhusudana31Dipartimento di Fisica del Politecnico and Istituto Nazionale della Materia Corso Duca degli Abruzzi24,10129Torino,Italia 2Departamento de Fisica,Universitade Estadual de Maringa,Avenida Colombo3690,87020-900,Maringa,Parana,Brazil3Raman Research Institute,C.V.Raman Avenue,Bangalore560080,IndiaReceived:29September1997/Received infinal from:10November1997/Accepted:18November1997Abstract.We analyse the influence of adsorbed ions and the resulting surface electricfield and its gradienton the anchoring properties of nematics with ionic conductivity.We take into account two physical mech-anisms for the coupling of the nematic director with the surface electricfield:(i)the dielectric anisotropyand(ii)the coupling of the quadrupolar component of theflexoelectric coefficient with thefield gradient.It is shown that for sufficiently largefields near saturated coverage of the adsorbed ions,there can be aspontaneous curvature distortion in the cell even when the anchoring energy is infinitely strong.We alsodiscuss the director distortion when the anchoring energy of the surface isfinite.PACS.61.30.-v Liquid crystals–61.30.Gd Orientational order of liquid crystals;electric and magneticfield effects on order–61.30.Cz Theory and models of liquid crystal structure1IntroductionAs in any other sample of condensed matter,the surface and interfacial properties of nematic liquid crystals(NLC) are rather complex.In many physical studies as well as practical devices like displays,it is necessary to anchor the orientation of the nematic director at appropriate sur-faces in specific directions.Several techniques have been invented for this purpose[1,2].In practice the anchor-ing has to be characterized by an angle dependent energy density and the simplest form proposed by Rapini and Pa-poular[3]consistent with the symmetry of the NLC has the following form:F s=−1a e-mail:barbero@polito.it devices the power consumption has to be reduced to the absolute minimum,and special care is taken to purify the sample.On the other hand,the effect offinite conductiv-ity has very interesting consequences,for example leading to a‘nonlocal’character of the anchoring energy itself. Indeed there have been experimental studies[8,9]which have clearly demonstrated the necessity to take into ac-count the influence of adsorbed charges on the surfaces in understanding the anchoring properties as functions of thickness and conductivity.In thefirst theoretical models the attention was confined to the coupling of the surface electricfield produced by the adsorbed charges with the dielectric anisotropy of the medium.All liquid crystals haveflexoelectric properties,and in particular the nonzero quadrupole density arising out of the orientational order in the medium[10]couples with electricfield gradients which can be quite large near the surfaces.In the present paper we will discuss the gen-eral electrostatic problem near surfaces which incorpo-rates both the dielectric andflexoelectric properties of the medium.The previous treatments of the problem[11–15] were based on the naive assumption that the dielectric and theflexoelectric torques are reduced to only surface con-tributions,ignoring the elastic torque completely.These were balanced by the torque due to the anchoring energy at the surface.In turn the problem was simply treated as a renormalization in the effective anchoring energy. This approach implies that in the case of strong anchoring there cannot be an instability due to the surface electric field.In this paper we present a more general analysis328The European Physical Journal B of this problem and show that even in the case of w→∞,a curvature instability can indeed occur above a thresholddouble layer potential.If w isfinite,the threshold poten-tial naturally gets reduced.2Theoretical modelWe consider the specific case of an NLC confined betweentwo glass plates treated for homeotropic alignment,i.e.,the easy axis n0is along z,the normal to the surface.θ(z)is the polar angle made by the director with respect to thez-axis.The problem is considered to be one-dimensional,i.e.,we assume that the surface has uniform properties inthe xy-plane.As we mentioned in Section1,the medium isassumed to contain ionic impurities,and the surface selec-tively adsorbs one type of ions(usually positively charged)with an adsorption energy E.As is well known in the elec-trolyte theory,such an adsorption produces a counterioncloud over a depth L d,called the Debye screening length[16–18].In turn,there is an electricfield which is verystrong near the surface(=E)and decays as we moveaway from it.As such,there is a fairly strongfield gra-dient near the surface.In usual liquid crystals,L d d,where d is the thickness of the sample.Hence,it is suffi-cient to treat the case of a semi-infinite sample boundedat z=0.The free energy density of the bulk NLC has thefollowing contributions:(i)the elastic part which is given byf el=12K33(n×∇×n)2;(2)(ii)dielectric coupling with the electricfield given byf diel=−a2Kθ 2(z)−a2sin[2θ(z)]θ (z)E(z),(5)whereθ =dθ/d z and e=(e1+e3)is the sum of the two flexoelectric coefficients defined in equation(4).The surface energy which is generally assumed to be of the Rapini-Papoular form given by equation(1)can have another contribution if the molecules are polar and the anchoring is homeotropic[19].It is now experimentally established that there is a surface polarization P s in such a case[20–22].The angle dependent part of the total surface energy density now becomes[23,24]f s=−12w cos2θ0−P s E0cosθ0,(6) whereθ0and E0are the values of the polar tilt angle and the electricfield at the surface(z=0).Equation(6)was used to describe planar to homeotropic transitions at the nematic surface[25].The equilibrium configuration in the bulk medium is given as usual by the Euler-Lagrange equation which yieldsKθ (z)−a2E (z)sin[2θ(z)]=0,(7) which has to be solved with the boundary conditions−Kθ +14πE2(z)+eE (z)θ=0,(10)for the Euler-Lagrange equation,and−Kθ +(eE0+w+P s E0)θ0=0,(11) for the boundary condition at z=0.We recall that the electricfield E(z)is generated in the present problem because of the adsorbed ions on the surfaces and the counterion cloud forming the diffuse dou-ble layer in the liquid crystal.Thefield distribution in this case is well known and it can be written to a very good approximation as[16]E(z)=E0exp(−z/L d).(12) The total energy for unit surface area is given byF=∞f d z+f s=∞18πE2(z)θ2(z)−eE(z)θ(z)θ (z)d z+1G.Barbero et al.:Surfacefield and anchoring energy329 3AnalysisThefield which acts as the source term for the instability(see Eq.(10))is localized close to the limiting surface atz=0.Thus it is appropriate to consider an approximatesolution of the formθ(z)=θ0+∆θ[1−exp(−z/L d)]=θb−∆θexp(−z/L d),(14)whereθb is the value ofθin the bulk(i.e.at z L d).The bulk energy density now takes the simple formf=12L d +a4πE20L dθb∆θ+eE0(∆θ)2,(17) and C=a4L d +eE032πE20L d+w+E0P s2+a16πE20L d+w+P s E0@(∆θ)=2α∆θ−βθb=0,(23)and∂F∂(∆θ)2=2α>0,(25) and the Hessian determinantH=∂2F∂θ2b−∂2F16πE20L d+2e2L d+w>0,(27)andK3+a4πE20L d+K3+a2+a2L d−4πa L d(29)and thefields corresponding to zero crossings ofµaregiven by[26]E0=8πeθ8πea L2d.(30)We can now discuss different possibilities.4.1Nematic with negative dielectric anisotropy, a<0In this case the term in the square root of equation(30)is always positive and larger in magnitude than thefirstterm.Hence in general there are two values of the surfacefield,one negative and another positive,corresponding todifferent species of adsorbed charges,between which thehomeotropic anchoring is stable,and beyond which it getsdestabilized.If theflexoelectric coefficient e is positive,thenegative thresholdfield is much larger than the positive330The European Physical Journal B field,and vice versa for a negative e.The physical meaningof these results is obvious:while a negative a leads to aninstability of the director if the electricfield is large enoughand has either sign,theflexoelectric term stabilizes thehomeotropic alignment for one of the signs of thefieldgradient depending on its own sign.4.2Nematic with positive dielectric anisotropy, a>0In this case two possibilities have to be considered accord-ing to the value of a.If a<8πK(31)the term in the square root is still positive,but smaller in magnitude than thefirst term in equation(30).The insta-bility occurs for some value of thefield,but the homeotro-pic alignment gets restabilized at a second higher thresh-oldfield in view of the quadratic dependence of the stabi-lizing dielectric torque on thefield.The sign of e decides the sign of thefield for which the destabilization occurs: for positive e,E0also should be positive,i.e.thefield gradient should be negative,and vice versa.If a>8πK(32)the term under the square root becomes negative and there cannot be any destabilization of the homeotropic alignment.The case when a=0will be discussed separately.5Threshold values forfinite anchoring energy When the anchoring energy isfinite,the zero crossings in relations(27,28)have to be numerically evaluated for given material parameters and the value of w.This has been done,and as can be expected,as w gets smaller,the thresholdfield needed for instability becomes lower.For example,if w=10−2erg/cm2,which corresponds to an extrapolation length of∼0.5µm,which can be attained in the laboratory[8],and a=−1,P s=−10−3esu[23,24], L d=0.1µm[17,18],K=10−7dyn[27],the threshold double layer potential is about22mV for e=+5×10−4 esu and∼30mV for e=−5×10−4esu[28].These values are easily attained in conducting nematic liquid crystals [17,18].We consider now two simple limiting cases.5.1Threshold for a dielectrically isotropic mediumFor simplicity we assume that P s=0in further analysis. In this case,when a=0,the stability conditions equa-tions(27,28)read as2e2L d +w>0,(33)andK3w−eE02|e|K3e−3e2+2Kw3e+3e2+2KweL d.(38)E3is of course positive for positive e.This means that thethreshold occurs for a double layer potential[27,28]V th∼K5×10−4∼10−3stat V∼0.3V.(39)Indeed such voltages are possible across double layers[29].5.2Threshold for a nonflexoelectric mediumIn this case e=0and as before we assume P s=0.Nowthe instability threshold,which can occur only if a<0,is given by| a|2L d+w<0,(40)and−2a4πK12E20−KwL d| a|,(42)whose form is reminiscent of the condition for Freedericksztransition.Again we get a double layer threshold voltagefor a=−4to be V th∼1V;of the same order as in theprevious case.The above analysis shows that even when the anchor-ing energy w is considered to be infinite,a sufficientlyG.Barbero et al.:Surfacefield and anchoring energy331strong surface electricfield generated by adsorbed ions can lead to a destabilization of the homeotropic alignment.If the dielectric anisotropy is negative and theflexoelectric coefficient e is positive,and the anchoring energy is mod-erate,the destabilizing double layer voltage can be quite low,of the order of0.1V,which can be easily attained in practical cases.Similar considerations are valid for planar alignment. In this case it is easier to destabilize nematic liquid crystals with positive a and for a positive surfacefield,materials with negative e.6ConclusionsWe have reexamined the influence of adsorbed ions on the orientation of nematic liquid crystals doped with ionic im-purities.The earlier approaches treated the problem only for the case of a weak surface anchoring,and treated the effect of the double layer potential as a purely surface ef-fect,ignoring the elastic distortion in the bulk.In this approximation,the surface electricfield just renormalizes thefinite anchoring energy at the surface and hence it does not influence the director profile if the anchoring is strong.We have removed this limitation in our analysis and shown that the surface electricfield can affect the bulk orientation of the director by distorting the director pro-file near the surface.Indeed such a distortion is found even when w→∞.This destabilization has two origins,due to both the dielectric anisotropy coupling with E20,and to theflexoelectric coefficient e=e1+e3coupling with the strongfield gradient near the surface.For homeotropic anchoring,a positive sign of e leads to a destabilization of the director for a negativefield gradient and hence a positive surfacefield,and is the origin of destabilization in materials with positive a.In this case at a second larger threshold the director profile gets restabilized in view of the E2-dependence of the dielectric coupling.In the case of negative dielectric anisotropy materials,such a restabi-lization is not possible.In fact it is often found that it is rather difficult to get a homeotropic alignment of materi-als with negative dielectric anisotropy[29].We feel that the phenomena discussed in this paper can account for these experimental results.Many thanks are due to A.K.Zvezdin for useful discussions. This work has been partially supported by Istituto Nazionale della Materia and by Dipartimento di Fisica del Politecnico di Torino in the framework of the collaboration between Politec-nico di Torino and the Raman Research Institute.References1.J.Cognard,Mol.cryst.Liq.Cryst.Suppl.Ser.1,1(1982).2. B.Jerome,Rep.Prog.Phys.54,391(1991).3. A.Rapini,M.Papoular,J.Phys.Colloq.France30,C4-54(1969).4.K.Okano,J.Murakami,J.Phys.Colloq.France40,C3-525(1979).5.G.Barbero,G.Durand,in Liquid Crystals in ComplexGeometries,edited by G.P.Crawford,S.Zumer(Francis, Taylor,London,1996).6.H.Yokoyama,Mol.Cryst.Liq.Cryst.165,265(1988).7.G.Barbero,G.Durand,J.Phys.France,51,281(1990).8.L.M.Blinov,A.Yu.Kabaenkov,A.A.Sonin,Liq.Cryst.5,645(1989).9. B.Valenti,M.Grillo,G.Barbero,P.Taverna Valabrega,Europhys.Lett.12,407(1990).10.J.Prost,J.P.Marcerou,J.Phys.France38,315(1977).11. A.V.Kaznachev,A.A.Sonin,Soviet Phys.Solid State25,528(1983).12. 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A.G.Petrov,A.Derzhanski,Mol.Cryst.Liq.Cryst.Lett.41,41(1977).24.M.Monkade,Ph.Martinot-Lagarde,G.Durand,Euro-phys.Lett.2,299(1986).25.J.D.Parson,Phys.Rev.Lett.41,877(1978).26.Of course asθb=∆θwhen w→∞,the problem canbe simplified very much,and the total energy given by equation(19)is now of the form F=Γθ2b,whereΓis a quadratic expression in E0,and naturally w drops out of the problem.The zero crossings ofΓnow yield the thresh-old values for E0and they are exactly the same as in equa-tion(30).27.P.G.de Gennes,J.Prost,The Physics of Liquid Crystals(Clarendon Press,Oxford,1993).28.N.V.Madhusudana,G.Durand,J.Phys.Lett.France46,L-200(1985).29.G.Basappa,N.V.Madhusudana,to be published.。

Ⅰ.认阅读单词1．cholera n．霍乱2．diarrhoea n．腹泻3．dehydration n．脱水4．contradictory adj.相互冲突的；对立的；不全都的5．germ n．微生物；细菌；病菌6．pump n．泵；抽水机；打气筒7．water pump水泵8．household n．一家人；家庭；同住一所(套)房子的人9．raw adj.未煮的；生的；未经处理的；原始的10．statistic n．[pl.]统计数字；统计资料；统计学11．epidemiology n．流行病学12．microscope n．显微镜13．protein n．蛋白质14．cell n．细胞；小房间；单间牢房15．virus n．病毒16．vaccine n．疫苗17．framework n．框架；结构18．theoretical framework理论框架19．rainbow n．彩虹20．concrete n．混凝土adj.混凝土制的；的确的；具体的21．plasma n．血浆22．aerospace n．航空航天工业23．patriotic adj.爱国的24．mechanical adj.机械的；发动机的；机器的25．mechanic n．机械师；机械修理工26．aviation n．航空制造业；航空；飞行27．jet n．喷气式飞机28．missile n．导弹29．astronomer n．天文学家30．astronomy n．天文学31．telescope n．望远镜Ⅱ.记重点单词1．severe adj.极为恶劣的；格外严峻的；严峻的2．subscribe v i.认购(股份)；定期订购；定期交纳(会费)3．suspect v t.& v i.怀疑；疑有；不信任n．犯罪嫌疑人；可疑对象4．blame v t.把……归咎于；责怪；指责n．责怪；指责5．handle n．把手；拉手；柄v t.处理；搬动；操纵(车辆、动物、工具等)；(用手)触碰6．link n．联系；纽带v t.把……连接起来；相关联7．substantial adj.大量的；价值巨大的；重大的8．decrease n．削减；降低；削减量v t.& v i.(使大小、数量等)削减；减小；降低9．transform v t.使改观；使转变形态v i.转变；转变10．thinking n．思想；思维；见解11．finding n．发觉；调查结果；(法律)判决12．initial adj.最初的；开头的；第一的13．solid adj.牢靠的；固体的；坚实的n．固体14．cast v t.(cast，cast)投射；向……投以(视线、笑容等)；投掷15．shadow n．阴影；影子；背光处16．pour v t.倒出；倾泻；斟(饮料)17．leadership n．领导；领导地位；领导才能18．trace v t.追溯；追踪；查出n．痕迹；遗迹；踪迹19．outstanding adj.优秀的；杰出的；明显的20．abstract adj.抽象的；理论上的n．(文献等的)摘要21．concept n．概念；观念22．besides prep.除……之外(还) ad v.而且；此外23．brilliant adj.聪颖的；绝妙的；光明的24．furthermore ad v.此外；再者25．fault n．弱点；过错26．shift n．转变；转换；轮班v i.& v t.转移；挪动；转向Ⅲ.知拓展单词1．frustrated adj.懊恼的；懊丧的；失意的→frustrate v t.使懊恼；使懊丧→frustration n．懊丧；懊恼；挫败2．infection n．感染；传染→infect v t.使感染；传染→infectious adj.感染的；传染的3．proof n．证据；证明；检验→prove v t.证明link v．证明是4．multiple adj.数量多的；多种多样的→multiply v i.& v t.乘；繁殖5．intervention n．介入；出面；干涉→intervene v i.干扰；介入6．pure adj.洁净的；纯的；纯粹的→purely ad v.完全地；纯粹地→purify v t.净化；使……洁净7．defend v t.保卫；防守；辩解→defense/defence n．防备；保卫；爱护8．assistant n．助理；助手→assist v t.& v i.挂念；帮忙→assistance n．挂念；帮忙；救济9．gifted adj.有天赋的；有天才的；天资聪慧的→gift n．礼物；天赋10．steady adj.稳定的；平稳的；稳步的→steadily ad v.稳定地；持续地11．vivid adj.生动的；鲜亮的；丰富的→vividly ad v.生动地；逼真地；鲜亮地1．idiom n．习语；成语2．ignore v t.忽视3．illegal adj.非法的；不合法的4．immediately ad v.马上5．immigration n．移民6．import v t.& n．进口；输入7．impression n．印象；感觉8．incorrect adj.不正确的；错误的Ⅳ.背核心短语1．once and for all最终地；彻底地2．subscribe to同意；赞同3．thanks to幸亏；由于4．break out(战斗、打斗等不开心的事情)突然开头；爆发5．in charge of主管；掌管6．come down患(病)；染上(小病)7．above all最重要的是；尤其是8．die from/of死于9．in time准时；迟早10．be likely to do sth 很可能做某事Ⅴ.悟经典句式1．Cholera used to be one of the most feared diseases in the world，until a British doctor，John Snow，showed how it could be overcome.(until引导的时间状语从句)在英国医生约翰·斯诺向人们呈现如何战胜霍乱之前，霍乱曾是世界上最令人恐惊的疾病之一。

小儿急性喉炎是一种常见的呼吸道感染性疾病，多发生于2～6岁的儿童，以冬春季为高发期[1]。

其主要病原体为病毒，如腺病毒、流感病毒、副流感病毒等，也可由细菌或真菌引起。

其临床特点为突发的犬吠样咳嗽、声音嘶哑、吸气性喉鸣、发热等，严重者可出现喉梗阻，危及患儿生命。

目前，小儿急性喉炎的治疗主要包括吸氧、抗感染、止咳、雾化吸入等，其中雾化吸入是一种有效的治疗手段，能够直接作用于呼吸道黏膜，减轻炎症，扩张气道，缓解症状[2]。

常用的雾化药物有布地奈德，布地奈德是一种吸入性糖皮质激素，具有强效的抗炎作用，能够抑制炎症细胞的浸润和活化，降低炎症因子的释放，减少黏液的分泌，改善气道的通畅性。

布地奈德的亲脂性强，能够促进呼吸道黏膜内脂肪酸的结合，使其慢慢分解，用游离的状态进入组织，保持药物浓度。

布地奈德的【摘要】 目的 探讨布地奈德雾化吸入对小儿急性喉炎的治疗效果及安全性。

方法 选取2022年1月- 2023年10月医院收治的小儿急性喉炎患者120例作为研究对象，根据组间基线资料均衡可比原则，采用随机数字表法分为对照组和观察组，每组各60例。

两组患儿均给予常规治疗，对照组在此基础上加用地塞米松静脉注射，观察组加用布地奈德雾化吸入。

比较两组患儿的临床症状改善时间、治疗效果及不良反应发生情况。

结果 采用布地奈德雾化吸入治疗方法的观察组患儿咳嗽、喉鸣、呼吸困难、喉梗阻等症状的改善时间均显著短于对照组，差异有统计学意义（P <0.05）。

观察组患儿的治疗总有效率为96.67%，高于对照组的81.67%，差异有统计学意义（P <0.05）。

两组患儿均未发生咽喉部不适、血糖升高、免疫功能抑制等严重不良反应，观察组患儿不良反应总发生率为5.00%，虽然低于对照组的10.00%，但差异无统计学意义（P >0.05）。

结论 布地奈德雾化吸入对小儿急性喉炎有良好的治疗效果，能有效缓解症状，缩短病程，提高疗效，且安全性较高。

托福听力tpo60 lecture1、2、3 原文+题目+答案+译文Lecture1 (1)原文 (1)题目 (3)答案 (5)译文 (5)Lecture2 (7)原文 (7)题目 (9)答案 (11)译文 (12)Lecture3 (13)原文 (13)题目 (16)答案 (18)译文 (18)Lecture1原文Listen to part of a lecture in an art history class.As you know, artists today can choose from an enormous selection of media, including water colors, acrylic paints, not to mention special pains formulated for almost any surface you might wanna paint on. But even so, oil paints are still the medium of choice among most professional artists and hobbyists. So why is that? well, for one thing, oil paints extremely versatile, suitable for many different painting styles, different subjects, and different sizes of work. Another advantage is thatthey're easy to use. Even for beginners, they can be manipulated. You can apply oil paint to a canvas. And then because they don't dry right away, they can be scraped off and paint it over.So you don't have to waste expensive material every time you make a change. Unlike acrylic paint, which really can't be moved once it's applied, acrylic paints dry very quickly. So in general, when using them, it's more difficult to make changes. And with watercolors, you can't really paint over a mistake, because it really diminishes the freshness of the colors. So oil paint is the medium of choice for many painters. Nowadays, anyway, in terms of art history, oil paints actually pretty young in Europe before the invention, rather, the development of oil paint, painters mostly used Tempera. Tempera was made with egg yolk. Believe it or not, the yoke acted as a binder. A binder enables the color pigment to stick to your canvas, and no temporal wasn't always yellow. If that's what you're thinking. Artists made their own paint by mixing egg yolk with a color pigment like powdered iron ore copper. But it dried very fast, which left little room for error or change.You really had to get it right the first time. Then in the early 15th century, a Flemish painter named Jan of Van Eyck started experimenting up after that emperor in one of the Nikes paintings cracked while drawing in the sun. He decided to try to make a paint that would avoid this fate. So he tried. And oil mixture, actually other painters before him had tried using oils as a binder. So while the Nikes credited with inventing oil paint, it's not entirely true. In Greece and Italy, olive oil had been used to prepare pigment mixtures, but the paint took a really long time to dry, just the opposite of tempera. But van Eyck had a secret recipe for his oil paint. He used linseed oil. Not only did this paint dry without cracking, van dyke also discovered that it could be applied in very thin layers. This technique gave the colors of depth that was previously unknown. And just as important, the linseed oil actually increased the brilliance of the color. So as a result, pigment oil mixtures became very popular among artists. Some tried to improve the paint by developing their own recipes, like uh, by using walnut oil, for instance, or by cooking their oil mixtures. But a greatmany began using some sort of oil as their binder.Now with all this experimentation with mixtures, well, it took a long time for artists to get comfortable with using these new oil paints to get a true feeling for how to apply them to the best effect. The early painters in oil like that Ike laid the paint down in thin layers with brush strokes that were so delicate that they're practically invisible. And it really wasn't until the end of the 16th century and in the 17th century that the full potential of oil paint was realized, for example, that's when artists finally began to combine delicately painted areas with thick brush strokes. So you could actually see the marks of the brush combining the rough and the smooth gives oil paintings great textural depth. Of course, the public who are used to smooth surfaces actually complained that these paintings looked unfinished. And some of that attitude carried over until later centuries, like, well, you're probably familiar with the work of the painter Vincent Van Gogh. Van gogh's famous nowadays for his thick, swirling brush strokes. But amazingly enough, his work was not appreciated back in the 19th century, and he sold just one painting during his lifetime. Of course, the French impressionists, who were his contemporaries, attained more popular acclaim, but they used a different technique. They applied oil paint and thick dabbs to depict the effects of light on the landscape.题目1.What does the professor mainly discuss?A. The relationship between painting techniques and types of paint that are usedB. Reasons for the changes in the popularity of oil paint since the seventeenth centuryC. The historical development and use of oil paintD. The main differences between oil paint and tempera2.What reasons does the professor give for the popularity of oil paint among modern artists?[Click on 2 answers.]A. It can be used for a number of painting styles.B. It allows artists to make changes.C. It does not fade easily.D. It can be made easily even by amateur painters.3.What property do tempera and acrylic paint have in common?A. They do not stick well to the canvas.B. They tend to crack as they dry.C. They tend to make colors look dull.D. They dry very quickly.4.What are two points the professor makes about the painter Jan van Eyck?[Click on 2 answers.]A. He did not invent the use of oil as a binder.B. He improved his own oil mixtures by heating them.C. He invented tempera.D. He applied oil paint to a canvas in thin layers.5.Why does the professor talk about combining delicate brushstrokes with thickbrushstrokes?A. To explain the popularity of van Eyck's paintingsB. To describe a difference between linseed oil and olive oil as a binderC. To indicate that artists became more experienced in the use of oil paintD. To point out a similarity between the painters van Eyck and van Gogh6.Why does the professor mention Vincent van Gogh?A. To emphasize that paintings made with thick brushstrokes were unpopular in the pastB. To show that artists did not know how to use oil paints correctly until the nineteenth centuryC. To describe the origin of a painting technique used by the French ImpressionistsD. To support his statement about when painters first began to use thick brushstrokes答案C ABD AD C A译文请听艺术史课上的部分内容。

科技英语试题及答案一、选择题（每题2分，共20分）1. The term "nanotechnology" refers to the manipulation of matter on an atomic, molecular, and supramolecular scale.A. TrueB. False2. Which of the following is NOT a characteristic of renewable energy sources?A. Infinite in supplyB. Environmentally friendlyC. Dependent on weather conditionsD. Non-renewable3. The process of converting solar energy into electrical energy is known as:A. SolarizationB. Photovoltaic effectC. Solar distillationD. Thermal radiation4. In the context of computer science, what does "AI" stand for?A. Artificial IntelligenceB. Advanced InterfaceC. Automated InputD. Application Interface5. The term "genome" is associated with:A. The complete set of genes in an organismB. The structure of a cellC. The study of geneticsD. The process of cell division6. What is the primary function of a transistor in an electronic circuit?A. To amplify signalsB. To store dataC. To convert light into electricityD. To filter signals7. The "Internet of Things" (IoT) refers to:A. A network of interconnected devicesB. The global network of computersC. A collection of internet protocolsD. The study of internet security8. Which of the following is a type of biotechnology?A. Genetic engineeringB. Quantum computingC. NanolithographyD. Nuclear fusion9. The "Greenhouse Effect" is related to:A. The warming of the Earth's surfaceB. The cooling of the Earth's surfaceC. The process of photosynthesisD. The formation of the ozone layer10. What does "CRISPR" stand for in the field of molecular biology?A. Clustered Regularly Interspaced Short Palindromic RepeatsB. Computer-Aided Research in Scientific ProjectsC. Comprehensive Research in Innovative ScienceD. Computational Research in Systematic Processes二、填空题（每题1分，共10分）1. The unit of electrical resistance is the ______.2. The process of converting sound waves into electrical signals is known as ______.3. In physics, the term "entropy" is used to describe the level of ______ in a system.4. The study of the chemical composition of planets is known as ______.5. The term "cybersecurity" refers to the protection of______ from cyber threats.6. The process of converting electrical energy into light is known as ______.7. The smallest unit of life that can replicate itself is called a ______.8. The process of creating new substances from existing ones is known as ______.9. The study of the structure and function of cells is known as ______.10. The process of converting light energy into chemical energy is known as ______.三、简答题（每题5分，共30分）1. Explain the concept of "machine learning" in artificialintelligence.2. Describe the role of a semiconductor in modern electronics.3. What is the significance of biodiversity in the context of environmental science?4. Discuss the potential impact of nanotechnology on medicine.四、论述题（共40分）1. Discuss the ethical considerations involved in the development and use of genetic engineering technologies. (20分)2. Analyze the potential benefits and challenges of implementing a global Internet of Things (IoT) network. (20分)答案：一、选择题1. A2. D3. B4. A5. A6. A7. A8. A9. A10. A二、填空题1. ohm2. transduction3. disorder4. cosmochemistry5. information systems6. electroluminescence7. cell8. synthesis9. cytology10. photosynthesis三、简答题1. Machine learning is a subset of artificial intelligence that enables computers to learn from and make decisions based on data, improving at tasks over time through experience without being explicitly programmed.2. Semiconductors are materials with electrical conductivity between that of a conductor and an insulator. They arecrucial in electronic devices like transistors and diodes, allowing for the control of electrical current and the amplification of signals.3. Biodiversity is significant in environmental science as it ensures the stability of ecosystems, supports ecological processes, and provides a variety of services and resources that are vital for human survival and well-being.4. Nanotechnology has the potential to。

第 21 卷 第 12 期2023 年 12 月Vol.21，No.12Dec.，2023太赫兹科学与电子信息学报Journal of Terahertz Science and Electronic Information Technology电离辐射前后双极型晶体管统计特性李顺a,b，代刚a,b(中国工程物理研究院 a.微系统与太赫兹研究中心，四川成都610200；b.电子工程研究所，四川绵阳621999)摘要：双极型晶体管性能统计分布在电离辐射之后会发生变化，从辐射前对称的正态分布转化为辐射后非对称的对数正态分布，这一统计特性转化缺乏清晰的物理图像。

为了从微观机理层次解释这一转化过程，通过大样本定制晶体管电离辐射效应实验，获得基极电流、界面陷阱电荷辐射前后的统计特性，发现两者统计特性转化具有一致性。

基于基极电流的解析物理模型分析发现辐射前后基极电流统计特性转化源自于界面陷阱电荷统计特性转化，并基于中心极限定理给出了界面陷阱电荷辐射前后统计特性转化的物理解释，即界面缺陷面密度的分散性转化源于多个随机变量以乘积形式实现界面缺陷物理过程。

关键词：电离辐射；双极型晶体管；统计特性中图分类号：TN432 文献标志码：A doi：10.11805/TKYDA2021363Statistical characteristics transformation mechanisms of bipolartransistor before and after irradiationLI Shun a,b，DAI Gang a,b(a.Microsystem and Terahertz Research Center，China Academy of Engineering Physics，Chengdu Sichuan 610200，China；b.Institute of Electronic Engineering，China Academy of Engineering Physics，Mianyang Sichuan 621999，China)AbstractAbstract：：The statistical distribution of bipolar transistors'performance will change after ionizing radiation, from a symmetrical normal distribution before radiation to an asymmetric log-normaldistribution. This statistical characteristic conversion lacks a clear physical image. In order to explainthis transformation process from the microcosmic level, a large sample of ionizing radiation effectexperiments for customized transistors are carried out to obtain the statistical characteristics of basecurrents and interface trapped charges before and after radiation, and the statistical characteristics of thetwo are found to be consistent. Based on the analytical physical model of the base current, it is found thatthe transformation of the base current statistical characteristics before and after radiation are originatedfrom the transformation of the interface trapped charges. Based on the central limit theorem, the physicalexplanation for the statistical characteristics transformation of interface trapped charges before and afterradiation is given, which comes from the physical model of interface defects in the form of multiplerandom variables.KeywordsKeywords：：irradiation；bipolar transistor；statistical distribution由于半导体器件在制造过程中材料的不一致性和工艺的波动，即便是同一厂商、同一批次的半导体器件，其电学参数也具有样本间分散性(sample-to-sample variability)。

The Ethics of Gene EditingGene editing has been a topic of debate for several years now, with scientists and ethicists divided on the ethical implications of this technology. The ability to manipulate genes and alter the genetic makeup of an organism has the potential to revolutionize medicine, agriculture, and even human evolution. However, it also raises several ethical concerns, including the possibility of creating a new class of genetically modified humans and the potential for unintended consequences.One of the primary ethical concerns surrounding gene editing is the potential for creating a new class of genetically modified humans. This could lead to a society that is divided based on genetic traits, with those who are genetically modified having advantages over those who are not. This could lead to discrimination and the creation of a genetic underclass, which is a violation of basic human rights. Additionally, there is the possibility that these genetic modifications could be passed down to future generations, leading to further genetic inequality.Another ethical concern is the potential for unintended consequences. Gene editing is a complex process that involves manipulating the genetic makeup of an organism. While scientists have made significant progress in this area, there is still much that is unknown about the long-term effects of these modifications. There is the possibility that these modifications could have unintended consequences, such as creating new diseases or causing existing ones to become more virulent.There is also the issue of consent. Gene editing has the potential to create a new class of humans, but it is unclear who would have access to this technology. If only the wealthy or privileged have access to gene editing, it could lead to further inequality and discrimination. Additionally, there is the issue of informed consent. It is unclear how much information individuals would need to make an informed decision about gene editing, and whether they would fully understand the risks and benefits of this technology.On the other hand, gene editing also has the potential to revolutionize medicine and agriculture. In medicine, gene editing could be used to cure genetic diseases, such as sicklecell anemia and cystic fibrosis. It could also be used to develop new treatments for cancer and other diseases. In agriculture, gene editing could be used to develop crops that are resistant to pests and disease, reducing the need for harmful pesticides and herbicides.In addition, gene editing could be used to address issues of social justice and equality. For example, it could be used to eliminate genetic diseases that disproportionately affect certain populations, such as sickle cell anemia in African Americans. It could also be used to address issues of food insecurity by developing crops that are more resilient to climate change and other environmental factors.In conclusion, the ethics of gene editing is a complex issue that requires careful consideration. While there are certainly potential benefits to this technology, there are also significant ethical concerns that must be addressed. The possibility of creating a new class of genetically modified humans, the potential for unintended consequences, and the issue of consent are just a few of the ethical concerns that must be addressed. Ultimately, it is up to society as a whole to decide whether the benefits of gene editing outweigh the ethical concerns.。

第27卷㊀第11期2023年11月㊀电㊀机㊀与㊀控㊀制㊀学㊀报Electri c ㊀Machines ㊀and ㊀Control㊀Vol.27No.11Nov.2023㊀㊀㊀㊀㊀㊀偶数相开关磁阻电机系统磁路平衡控制策略研究徐帅1,㊀陶路委1,㊀贾东强1,㊀程志平1,㊀韩国强2(1.郑州大学电气与信息工程学院,河南郑州450000;2.中国矿业大学电气工程学院,江苏徐州221116)摘㊀要:针对传统偶数相开关磁阻电机磁路不平衡带来的转矩输出性能降低的问题,提出了一种磁路平衡控制策略㊂首先,分析了不同绕组连接方式下偶数相开关磁阻电机的磁场分布情况,揭示了单极性励磁是不平衡磁路产生的主要原因㊂然后,提出采用集成式功率变换器拓扑进行双极性励磁,保证磁路的平衡,确定了双极性励磁下功率器件的开关顺序,阐述了所提磁路平衡控制策略的工作原理和实施方法㊂最后,进行了仿真和实验分析,验证了所提磁路平衡控制策略能够有效增强偶数相开关磁阻电机系统转矩输出能力,同时在系统成本㊁算法复杂度和可靠性方面有明显的优势㊂关键词:开关磁阻电机;转矩脉动;磁路平衡控制;绕组连接方式;集成式功率变换器拓扑DOI :10.15938/j.emc.2023.11.016中图分类号:TM352文献标志码:A文章编号:1007-449X(2023)11-0163-10㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀收稿日期:2022-01-22基金项目:中国博士后科学基金(2020M286343);国家自然科学基金(52107215);河南省科技攻关项目(212102210010);2020中原青年拔尖人才项目(ZYYCYU202012182)作者简介:徐㊀帅(1991 ),男,博士,副教授,研究方向为电机系统可靠性建模与控制;陶路委(1997 ),男,硕士研究生,研究方向为双定子磁阻电机控制;贾东强(1997 ),男,硕士,研究方向为开关磁阻电机效率优化控制;程志平(1974 ),男,博士,副教授,研究方向为微电网系统调度与优化;韩国强(1990 ),男,博士,讲师,研究方向为电机系统故障诊断与容错控制㊂通信作者:程志平Magnetic circuit balance control strategy of even-phaseswitched reluctance motor systemXU Shuai 1,㊀TAO Luwei 1,㊀JIA Dongqiang 1,㊀CHENG Zhiping 1,㊀HAN Guoqiang 2(1.School of Electric and Information Engineering,Zhengzhou University,Zhengzhou 450000,China;2.School of Electric Engineering,China University of Mining and Technology,Xuzhou 221116,China)Abstract :Focusing on the problem of reducing torque output performance caused by unbalanced magnetic circuit of traditional even-phase switched reluctance motor,a novel magnetic circuit balance control strat-egy was proposed.Firstly,the magnetic field distribution was analyzed in different winding connectionmethods for even-phase switched reluctance motor,indicating that unipolar excitation is the main cause of unbalanced magnetic circuit.Then,the integrated power converter topology was adopted to realize the bi-polar excitation and ensure the balance of magnetic circuit.Next,the switching sequence of power de-vices under bipolar excitation was determined,and the working principle and implementation method of the proposed magnetic circuit balance control strategy were described.Finally,the simulation and experi-mental analysis were carried out,proving that the proposed magnetic circuit balance control can enhance the torque output performance.Also,the proposed control strategy owns significant advantages in systemcost,algorithm complexity and reliability.Keywords:switched reluctance motor;torque ripple;magnetic circuit balance control;winding connec-tion;integrated power converter topology0㊀引㊀言近年来,随着全球传统燃油汽车产业的快速发展与石油短缺㊁环境污染之间的矛盾日益突出,新能源汽车因高效节能的显著优势,成为人类解决环境危机的主要途径[1]㊂驱动电机作为新能源汽车的核心环节,需要满足如下技术要求:1)宽调速范围内的高效率运行㊂该要求能够弥补新能源汽车由于电池续航能力不足带来的劣势㊂2)高功率密度㊂该要求是实现新能源汽车驱动系统高集成度和轻量化的基础㊂3)低转矩脉动㊂该要求能够保证新能源汽车乘坐的舒适性㊂4)高可靠性㊂该要求能够保证新能源汽车的安全性㊂相比于交流感应电机和永磁同步电机来说,开关磁阻电机(switched reluc-tance motor,SRM)具有结构简单㊁无需稀土永磁材料㊁制造成本低㊁调速范围宽㊁高节能性和高可靠性等优势,成为了新能源汽车高性能驱动电机的优先选择之一㊂但是由于双凸极特性和脉冲供电方式的存在,SRM的转矩输出性能受到影响,存在较大的转矩脉动,限制了SRM的进一步推广和应用[2-4]㊂为了抑制SRM的转矩脉动,国内外学者从电机控制和本体设计两方面进行研究㊂目前,SRM通过电机控制抑制转矩脉动可以分为间接转矩控制和直接转矩控制两大类㊂间接转矩控制通常利用转矩分配函数,选择合适的换相点,将参考转矩有序分配给各相,再通过各相的转矩㊁位置和电流关系,得到参考电流,依据参考电流改变驱动信号,使实际电流跟随参考电流的变化,进而实现转矩的控制㊂现阶段在间接转矩控制的研究中,学者们主要通过改进转矩分配函数,优化换相点,提升SRM系统转矩脉动抑制性能[5-7]㊂相比于间接转矩控制,直接转矩控制依据参考转矩和实际转矩的偏差直接产生驱动信号,能够有效提升SRM系统的动态响应速度㊂现阶段在直接转矩控制的研究中,学者们主要通过扇区的优化[8]㊁模型预测[9]和模糊调节[10]等策略增强转矩脉动抑制效果,但是在直接转矩的实施过程中存在开关频率不可控㊁算法复杂和容易出现尖峰电流等缺点,限制了直接转矩控制的推广和应用㊂SRM通过电机本体设计抑制转矩脉动方面的方法可以分为新型SRM拓扑结构和SRM的优化两大类㊂在新型SRM拓扑结构的研究中,学者们通常通过优化电磁路径的方法来进行转矩脉动的抑制[11]㊂文献[13]通过设计新型内外错齿转子,避免内外定子产生磁场的耦合,提出一种磁场解耦型双定子结构SRM,有效降低了转矩脉动㊂在SRM优化方面,通常采用多目标优化算法,合理选择定转子极数㊁定转子极弧系数和转子外形及尺寸等参数,进而能够有效抑制转矩脉动㊂文献[14]采用多目标系统优化算法,实现了三相6/4结构SRM的效率提高和转矩脉动的抑制㊂文献[15]采用粒子群算法,能够使SRM系统转矩脉动的抑制效果达到50%以上㊂虽然SRM现有的转矩脉动抑制方法取得了良好的应用效果,但是往往会带来算法复杂度的提升或者成本的增加㊂同时在对SRM转矩脉动产生机理和抑制策略的不断深入研究中,逐渐发现电磁路径的分布情况是影响SRM转矩脉动的重要因素㊂而相比于奇数相SRM,偶数相SRM的电磁路径分布不对称,增大了相间互感和转矩脉动[16]㊂文献[17]研究了四相8/6结构SRM的互感特性,结果表明样机存在电磁不对称励磁相,长磁路励磁相的负互感使输出转矩有所减小,一个导电周期内转矩波形不规则,增大了转矩脉动㊂文献[18]研究了六相12/10结构SRM五种绕组连接方式下的磁路分布㊁互感特性和运行性能,确定了最优的绕组连接方式,降低了转矩脉动㊂文献[19]详细介绍了六相SRM的非对称磁路和电流不一致现象的产生机理,并提出采用不等磁轭结构和多目标优化的方式来改善SRM的转矩性能,取得了良好的应用效果㊂但是上述两种策略均无法实现整个运行周期内的磁路对称,进而无法消除不对称磁路带来的转矩脉动现象㊂文献[20]的研究结果表明绕组连接方式的改变能够实现磁场的动态调节,提升SRM的运行性能㊂虽然文献[21]提出了偶数相SRM不对称电磁路径的解决方法,但是所需成本过高,实施过程复杂㊂因此亟需研究一种新型磁路平衡控制策略,为偶数相SRM转矩脉动的抑制提供新的解决思路㊂本文首先进行偶数相SRM的磁路分析,通过有限元建模和理论分析研究转子偶数齿和奇数齿偶数相SRM的磁链和转矩输出特性,归纳不对称磁路的产生机理㊂然后提出采用模块化集成式功率变换器461电㊀机㊀与㊀控㊀制㊀学㊀报㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第27卷㊀拓扑实现磁路平衡控制,分析双极性励磁模式下功率器件的开关逻辑,给出磁路平衡控制策略的实施原则㊂最后通过仿真分析和样机实验,验证所提磁路平衡控制能够有效改善偶数相SRM 的转矩性能,提升系统运行的稳定性㊂同时,所提磁路平衡控制策略无需复杂的算法和优化过程,不影响现有的直接转矩控制或者间接转矩控制策略的实施,因此后续的研究中可以结合现有转矩控制策略,增强偶数相SRM 旋转的平滑性㊂1㊀偶数相开关磁阻电机磁路分析1.1㊀偶数相开关磁阻电机系统通常情况下,SRM 系统由SRM 本体㊁功率变换器㊁检测环节和控制器4部分组成㊂以四相8/6结构SRM 为例,其组成如图1(a)所示㊂当SRM 系统运行时,首先通过检测环节检测各相电流信息(i ph )和转子位置(θ),然后由控制器计算SRM 的实时转速(n s ),并结合给定的转速(n ∗)和设置的控制策略,生成各个功率开关管的驱动信号(DS ),驱动电机正常运转[3-6]㊂图1㊀四相SRM 系统Fig.1㊀Four-phase SRM system为了保证SRM 系统的控制性能和容错能力,功率变换器选择常用的不对称半桥功率变换器(asym-metric half-bridge power converter,AHBPC)拓扑,如图1(b)所示㊂其中:U s 为直流供电电源,一般选用蓄电池或者开关电源;C 为直流母线电容,用来进行滤波和吸收负电压续流阶段回馈的绕组储能;S1~S8为开关管;D1~D8为二极管,为避免直通故障,需要选用超快恢复二极管;L a ㊁L b ㊁L c 和L d 分别为A 相㊁B 相㊁C 相和D 相的绕组㊂在AHBPC 的驱动下,能够有效实施电压斩波控制(voltage chopping con-trol,VCC)㊁电流斩波控制(current chopping control,CCC)和角度位置控制(angle position control,APC)等策略,保证系统稳定可靠运行[22]㊂1.2㊀磁路分析在偶数相SRM 系统中,由于不对称半桥功率变换器带来的单极性电流励磁,会导致磁路不平衡现象的出现[16-21]㊂为了有效揭示不平衡磁路的产生机理,本文分别以转子偶数齿的四相8/6结构SRM 和转子奇数齿的四相12/9结构SRM 为分析对象,进行不同绕组连接方式下偶数相SRM 的磁极分布和磁路分析㊂图2(a)和图2(b)为四相8/6结构SRM 的两种绕组连接方式,分别命名为连接方式I 和连接方式II㊂图2(a)为绕组连接方式I 的示意图㊂此时SRM 定子极的磁场分布为NSNSSNSN㊂在两相同时励磁时,A 相和B 相㊁B 相和C 相㊁C 相和D 相之间为短磁路分布,而在D 相和A 相之间为长磁路分布,分别如图2(c)和图2(d)所示㊂若采用图2(b)所示的绕组连接方式II,在该绕组连接方式I 的影响下,从定子A1极开始,8个定子极的磁场分布为NNNNSSSS㊂在两相同时励磁时,A 相和B 相㊁B 相和C 相以及C 相和D 相之间的磁场分布为长磁路分布,而在D 相和A 相之间的磁场分布为短磁路分布,分别如图2(e)和图2(f)所示㊂综上所述,四相8/6结构SRM 在绕组连接方式I 时以短磁路运行为主,在绕组连接方式II 时以长磁路运行为主,均出现明显的磁路不平衡现象㊂对于转子奇数齿的四相12/9结构的SRM 来说,磁路分布与四相8/6结构SRM 明显不同,具有更高的复杂性㊂本文选取两种典型的绕组连接方式,分别命名为连接方式I 和连接方式II,如图3(a)和图3(b)所示㊂图3(a)为绕组连接方式I 的示意图,此时从定子A1极开始,12个定子极的磁场分布为NSNNSNSNSNSS㊂在两相同时励磁时,A 相和B 相㊁C 相和D 相以及D 相和A 相之间为短磁路分布,如图3(c)所示㊂而在B 相和C 相之间为长磁路分布的现象,如图3(d)所示㊂图3(b)为绕组连接方式II 的示意图,此时从定子A1极开始,12个定子极的磁场分布为NNNSSSNNNSSS,类似绕组连接方式I,此时也会出现长磁路和短磁路交错分布的现象㊂561第11期徐㊀帅等:偶数相开关磁阻电机系统磁路平衡控制策略研究图2㊀四相8/6结构SRM 绕组连接方式和磁路分析Fig.2㊀Winding connection and magnetic circuit analy-sis for four-phase 8/6SRMsystem图3㊀四相12/9结构SRM 绕组连接方式和磁路分析Fig.3㊀Winding connection and magnetic circuit analy-sis for four-phase 12/9SRM system从上述分析可知,转子偶数齿和转子奇数齿偶数相SRM 均存在磁路不平衡现象㊂而上述磁路不平衡现象的产生是由于偶数相SRM 采用AHBPC 驱动时,只能采用单极性电流励磁模式,即整个运行过程中相电流方向不变,造成定子磁极分布的相对固定,出现长磁路和短磁路交错分布的现象,进而造成磁路不平衡的现象㊂磁路不平衡现象的出现会影响偶数相SRM 的运行性能,以四相8/6结构SRM 为例进行分析㊂在单相励磁时,四相8/6结构各相磁路相同,具有相同的磁链和转矩特性,因此只需研究两相励磁时磁路不平衡对SRM 输出性能的影响,如图4所示㊂图4㊀四相SRM 磁链和转矩对比Fig.4㊀Comparison of flux and torque for four-phaseSRM system由于绕组连接方式I 和II 下均只存在短磁路和长磁路两种情况,因此分别对SRM 两相励磁时短磁路和长磁路下的运行情况进行分析㊂图4(a)为四相8/6结构SRM 在短磁路和长磁路运行时的磁链对比㊂从图中可以看出,短磁路运行时磁链明显大于长磁路运行时的磁链,进而可知在短磁路运行时661电㊀机㊀与㊀控㊀制㊀学㊀报㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第27卷㊀SRM 产生更高的转矩,且两种情况下转矩的偏差随着励磁电流和磁路饱和度的增加而增大,如图4(b)所示㊂综上分析可以看出,偶数相SRM 在短磁路和长磁路情况下具有不同的输出转矩,而对所述的绕组连接方式下,不管对于转子偶数齿或者转子奇数齿的偶数相SRM 来说,不可能在一个转子周期内保证全程短磁路或者长磁路运行,进而会带来明显的转矩脉动㊂2提出的磁路平衡控制方法2.1㊀集成式变换器拓扑为了实现偶数相SRM 系统的短磁路运行,需要改变各个定子磁极的磁场分布㊂传统的AHBPC 只能通入单极性的电流,无法通过改变电流方向使长磁路运行转变为短磁路运行,因此本文提出采用集成式变换器拓扑的方式进行双极性电流励磁,如图5所示㊂其中,电流从绕组 + 端流入为正向运行,从 - 端流入为负向运行㊂图5㊀集成式变换器拓扑Fig.5㊀Integrated power converter topology所采用的集成式变换器拓扑由模块I 和模块II 组成,模块I 和模块II 均为三相全桥功率变换模块㊂相比于图1(b)所示的传统不对称半桥功率变换器,集成式变换器拓扑有效减少了所需功率器件的数目,只需要12个功率器件㊂由于三相全桥功率变换模块的广泛使用,其成本相比于不对称半桥功率变换器会大幅度降低㊂同时集成化的结构和少功率器件的特性会减小功率变换器体积和故障发生率,为系统功率密度和可靠性的提高奠定基础㊂所采用的集成式变换器拓扑具有正向励磁(Mode 1)㊁正向上零电压续流(Mode 2)㊁正向下零电压续流(Mode 3)㊁正向退磁(Mode 4)㊁反向励磁(Mode 5)㊁反向上零电压续流(Mode 6)㊁反向下零电压续流(Mode 7)和反向退磁(Mode 8)等8种运行模式㊂以B 相为例,不同模式下电流路径如图6所示㊂图6㊀不同模式下电流路径Fig.6㊀Current path in different modes通过将8种运行模式有效组合能够实现偶数相SRM 的双极性运行,进而保证电机磁路平衡,提高SRM 系统的转矩输出性能㊂2.2㊀磁路平衡控制所提出的磁路平衡控制策略不影响SRM 常用的VCC㊁CCC 和APC 等控制策略的实施,因此以CCC 策略为例进行磁路平衡控制策略实施原则的说明,具体如图7所示㊂在软斩波模式下,利用转速反馈,使给定转速(n ∗)和n 经PI 调节器生成参考电流(I ref ),将I ref 与i ph 经电流滞环控制器生成控制信号,并将其与对应相的位置信号相与,得到对应相761第11期徐㊀帅等:偶数相开关磁阻电机系统磁路平衡控制策略研究的驱动信号㊂在单极性运行模式下,斩波信号和位置信号分别用来驱动上管和下管㊂在导通区间,交替采用Mode 1和Mode 3,而在退磁区间,采用Mode 4,从而能够实现SRM 系统的稳定运行㊂图7㊀CCC 原理Fig.7㊀Principles of CCC为了克服磁路不平衡造成的SRM 系统转矩性能下降问题,本文提出采用集成式变换器拓扑,能够实现电流双极性模式的磁路平衡控制策略,其实施方法如图8所示,采用正向运行和反向运行相互交替的模式,在一个电流周期内可以分为两个转子运行周期,分别命名为第I 运行周期和第II 运行周期,在第I 运行周期为正向运行,在第II 运行周期为反向运行㊂在第I 运行周期,在导通区间,采用Mode 1和Mode 3交替运行,而在退磁区域,采用Mode 4㊂在第II 运行周期,在导通区间,采用Mode 5和Mode 6交替运行,而在续流区间,采用Mode8㊂图8㊀磁路平衡控制运行模式Fig.8㊀Magnetic circuit balance control operation mode在提出的磁路平衡控制方式的作用下,对于四相8/6结构SRM 来说,第一个转子周期内的磁场分布为NSNSSNSN,第二个转子周期内的磁场分布为SNSNNSNS,通过两个转子周期的磁场共同交替分布,进而实现短磁路运行,如图9(a)所示㊂对于四相12/9结构的SRM 来说,第一个转子周期内的磁场分布为NNSNSNSNSSNS,第二个转子周期内的磁场分布为SSNSNSNSNNSN,从而能够保证SRM 的磁路平衡运行㊂图9㊀磁路平衡控制下磁场分布Fig.9㊀Magnetic field distribution under the control ofmagnetic circuit balance3㊀仿真分析为了验证所提磁路平衡控制策略的有效性,依据电压方程㊁转矩方程和机电联系方程,在MAT-LAB /Simulink 中搭建一个150W 四相8/6结构SRM 的仿真模型,其中考虑磁路不平衡影响的磁链特性和转矩特性采用查找表的方式进行建模㊂设定仿真步长5μs,开通为2ʎ,关断角25ʎ,给定转速1000r /min,负载转矩1.5N㊃m,样机在常规单极性控制(采用图4(a)所示的绕组连接方式I)和磁路平衡控制下的仿真波形如图10所示㊂其中,DS 1㊁DS 4和T e 分别为开关管S1的驱动信号㊁开关管S4的驱动信号和电磁转矩㊂由仿真结果可知,单极性运行时开关管S1的开关管频率远大于S4的开关频率,因此S1上产生的热应力会远大于S4上产生的热应力㊂而采用双极性控制时,DS 1的频率将为一半,同时DS 4的频率有861电㊀机㊀与㊀控㊀制㊀学㊀报㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第27卷㊀所提高,使DS 1和DS 4的频率接近,进而能够平衡开关管S1和S4上的热应力,降低器件的最大失效率㊂同时可以看出,在单极性运行时,虽然CCC 控制能够保证各相电流的对称,但是在长磁路运行时输出转矩有所减少,此时转矩脉动(γ)为42.6%,而所提出的磁路平衡控制策略能够保证整个运行周期内的短磁路运行,此时转矩脉动为34.3%,实现了转矩输出性能的改善㊂同时在负载转矩1.5N㊃m 时,在转速从200r /min 到1200r /min 的范围内,所提磁路平衡控制策略均能够有效降低转矩脉动,如图11所示㊂图10㊀样机仿真波形Fig.10㊀Simulation waveforms按照文献[23-24]所示的功率器件损耗解析结算方法,计算各个功率器件的损耗㊂以模块II 为例,表1对比了单极性软斩波励磁㊁单极性交替斩波励磁和磁路平衡控制策略下功率管的损耗分布情况㊂可以看出,在单极性软斩波励磁㊁单极性交替斩波励磁和磁路平衡控制策略下,功率管最大损耗和最小损耗的差分别为3.46㊁3.19㊁2.15W,因此可以得到磁路平衡控制下能够明显改善功率器件热分布的不平衡性㊂图11㊀不同控制策略下转矩脉动对比Fig.11㊀Torque ripple comparison under differentcontrol strategies表1㊀不同控制方式下功率管损耗分布Table 1㊀Power loss distribution in different control modes功率管功率器件损耗/W单极性软斩波单极性交替斩波磁路平衡控制S7 3.44 2.37 4.15S8 4.86 2.78 4.15S9 2.60 5.56 2.00S10 1.40 4.74 2.00S11 3.44 2.37 4.15S124.862.784.154㊀实验验证为了验证本文所提磁路平衡控制策略的有效性,研制了一台四相8/6结构150W 的小功率SRM,并配备了动态扭矩测量仪(HCNJ-101)和磁粉制动器分别进行转矩的测量和调节㊂同时搭建了基于TMS320F28335的样机控制平台,MOSFET 选用FQA160N08,二极管选用MUR6020,驱动芯片选用TLP250㊂硬件实验平台的具体构造如图12所示㊂图12㊀硬件实验平台Fig.12㊀Hardware experimental platform961第11期徐㊀帅等:偶数相开关磁阻电机系统磁路平衡控制策略研究为了验证短磁路和长磁路对偶数相SRM 电磁性能的影响,将A 相和B 相分别按照图2所示连接方式I 和连接方式II 串联连接,其中在连接方式I 时,A 相和B 相之间短磁路运行,而在连接方式II 时,A 相和B 相之间长磁路运行㊂考虑到A 相和B 相共同运行的区间,转子在A 相22.5ʎ时,测量得到驱动信号㊁A 相电流和绕组两端电压(u ab )如图13(a)和图13(b)所示㊂接下来,依据电压方程,进行磁链的解析计算[17],得到的计算结果如表2所示㊂从表2中可以看出,实验测量结果和仿真结果具有较好的吻合度,同时短磁路运行和长磁路运行下磁链有明显的差异,从而证明了不同绕组连接方式对偶数相SRM 的电磁性能有明显的影响,与理论分析结果相符㊂表2㊀磁链测量结果对比Table 2㊀Results comparison for flux measurement电流/A 短磁路长磁路仿真磁链/Wb 实验磁链/Wb 误差/%仿真磁链/Wb 实验磁链/Wb 误差/%50.00210.002412.500.00210.002412.50100.04160.04558.570.03950.0418 5.50150.05990.0626 4.300.05720.0547-4.57200.07430.0725-2.480.06910.0645-7.13250.07950.0766-3.780.07220.0687-5.09图13㊀磁链测量时驱动信号㊁电流和电压波形Fig.13㊀Drive signals ,current and voltage waveformsduring flux measurement㊀㊀保证和仿真时相同的开通角㊁关断角㊁给定转速和负载转矩,图14(a)为样机在磁路平衡控制时的运行波形,可以看出各相电流幅值对称,有效说明所提磁路平衡控制策略能够驱动样机正常运行㊂同时样机生成的电磁转矩波形对称,解决了单极性运行时长短磁路交替带来的电磁转矩峰值或者谷值过大的问题,进而验证了理论推导和仿真分析的有效性,如图14(b)所示㊂而在不同的运行转速下,相比于单极性运行,样机在所提磁路平衡控制策略的作用下,转矩脉动平均降低5.63%以上,如图15所示㊂图14㊀实验波形Fig.14㊀Experimental waverforms071电㊀机㊀与㊀控㊀制㊀学㊀报㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第27卷㊀图15㊀实验条件下转矩脉动对比Fig.15㊀Torque ripple comparison in experimentalconditions5㊀结㊀论本文通过分析不同绕组连接方式下磁场的分布情况,揭示了偶数相开关磁阻电机磁路不平衡现象的产生机理㊂在此基础上,提出了结合集成式功率变换器和双极性励磁的磁路平衡控制策略,并且进行了仿真分析和实验验证㊂结果表明所提磁路平衡控制策略具有以下优点:1)采用集成式功率变换器驱动,平均每相功率器件数目由不对称半桥功率变换器的4个降低到3个,减少了系统的成本,增强了系统的可靠性;2)所提磁路平衡控制策略实施简单,无需复杂的参数调节和优化过程,同时不影响后续采用直接转矩控制或者间接转矩控制进一步实现转矩脉动的降低,具有良好的普适性;3)所提磁路平衡控制策略能够有效改善偶数相开关磁阻电机的转矩输出能力,不采用任何优化策略的情况下,转矩脉动抑制效果增强5.63%以上㊂参考文献:[1]㊀新能源汽车国家大数据联盟,中国汽车技术研究中心有限公司,重庆长安新能源汽车有限公司.中国新能源汽车大数据研究报告(2019)[M].北京:社会科学文献出版社,2019. [2]㊀戈宝军,魏瑶,韩继超,等.开关磁阻电机定子铁损分布的时步有限元分析[J].电机与控制学报,2020,24(7):20.GE Baojun,WEI Yao,HAN Jichao,et al.Time-stepping finite el-ement analysis of stator iron loss distribution of switched reluctance motor[J].Electric Machines and Control,2020,24(7):20.[3]㊀CAI Jun,ZHAO Xingqiang.An on-board charger integrated powerconverter for EV switched reluctance motor drives[J].IEEE Transactions on Industrial Electronics,2021,68(5):3684. [4]㊀FENG Liyun,SUN Xiaodong,TIAN Xiang,et al.Direct torquecontrol with variable flux for an SRM based on hybrid optimizationalgorithm[J].IEEE Transactions on Power Electronics,2022,37(6):6688.[5]㊀费晨,颜建虎,汪盼,等.基于改进的转矩分配函数法的开关磁阻电机转矩脉动抑制[J].电工技术学报,2018,33(S2):394.FEI Chen,YAN Jianhu,WANG Pan,et al.Torque ripple sup-pression of switched reluctance motor based on modified torque sharing function[J].Transactions of China Electrotechnical Soci-ety,2018,33(S2):394.[6]㊀孙庆国,吴建华.基于转矩分配函数在线修正的开关磁阻电机转矩脉动抑制策略[J].电机与控制学报,2017,21(12):1.SUN Qingguo,WU Jianhua.Torque ripple suppression strategy of switched reluctance motor based on on-line correction of torque dis-tribution function[J].Electric Machines and Control,2017,21(12):1.[7]㊀王喜莲,许振亮,王翠.开关磁阻电机转矩脉动与铜耗最小化控制研究[J].电机与控制学报,2015,19(7):7.WANG Xilian,XU Zhenliang,WANG Cui.Research on torque ripple and copper loss minimization control of switched reluctance motor[J].Electric Machines and Control,2015,19(7):7. [8]㊀曹鑫,户红艳,颜宁,等.扇区实时优化的开关磁阻电机直接转矩控制方法[J].电工技术学报,2018,33(19):9.CAO Xin,HU Hongyan,YAN Ning,et al.Direct torque control of switched reluctance motor with real-time optimization of sectors [J].Transactions of China Electrotechnical Society,2018,33(19):9.[9]㊀李岩,王国峰,李存贺,等.开关磁阻电机有限控制集预测转矩控制[J].电机与控制学报,2019,23(10):10.LI Yan,WANG Guofeng,LI Cunhe,et al.Finite control set pre-dictive torque control method for switched reluctance motor drives [J].Electric Machines and Control,2019,23(10):10. [10]㊀周凯,石增.开关磁阻电机转矩脉动抑制技术[J].电机与控制学报,2019,23(12):8.ZHOU Kai,SHI Zeng.Torque ripple suppression technology ofswitched reluctance motor[J].Electric Machines and Control,2019,23(12):8.[11]㊀颜建虎,汪盼,费晨.模块化开关磁阻式横向磁通电机设计与分析[J].中国电机工程学报,2018,38(22):7.YAN Jianhu,WANG Pan,FEI Chen.Design and analysis ofmodular switched reluctance transverse flux motor[J].Proceed-ings of the CSEE,2018,38(22):7.[12]㊀LEE C H T,CHAU K T,LIU C,et al.Mechanical offset fortorque ripple reduction for magnetless double-stator doubly salientmachine[J].IEEE Transactions on Magnetics,2014,50(11):8103304.[13]㊀闫文举,陈昊,马小平,等.不同转子极数下磁场解耦型双定子开关磁阻电机的研究[J].电工技术学报,2021,36171第11期徐㊀帅等:偶数相开关磁阻电机系统磁路平衡控制策略研究。

Unit OneTask 1⑩④⑧③⑥⑦②⑤①⑨Task 2① be consistent with他说，未来的改革必须符合自由贸易和开放投资的原则。

② specialize in启动成本较低，因为每个企业都可以只专门从事一个很窄的领域。

③ d erive from以上这些能力都源自一种叫机器学习的东西，它在许多现代人工智能应用中都处于核心地位。

④ A range of创业公司和成熟品牌推出的一系列穿戴式产品让人们欢欣鼓舞,跃跃欲试。

⑤ date back to置身硅谷的我们时常淹没在各种"新新"方式之中，我们常常忘记了，我们只是在重新发现一些可追溯至涉及商业根本的朴素教训。

Task 3T F F T FTask 4The most common viewThe principle task of engineering: To take into account the customers ‘ needs and to find the appropriate technical means to accommodate these needs.Commonly accepted claims:Technology tries to find appropriate means for given ends or desires;Technology is applied science;Technology is the aggregate of all technological artifacts;Technology is the total of all actions and institutions required to create artefacts or products and the total of all actions which make use of these artefacts or products.The author’s opinion: it is a viewpoint with flaws.Arguments: It must of course be taken for granted that the given simplified view of engineers with regard to technology has taken a turn within the last few decades. Observable changes: In many technical universities, the inter‐disciplinary courses arealready inherent parts of the curriculum.Task 5① 工程师对于自己的职业行为最常见的观点是：他们是通过应用科学结论来计划、开发、设计和推出技术产品的。

Colloids and Surfaces A:Physicochem.Eng.Aspects 480(2015)91–104Contents lists available at ScienceDirectColloids and Surfaces A:Physicochemical andEngineeringAspectsj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /c o l s u r faSelf-assembly control via molecular recognition:Effect ofcyclodextrins on surfactant micelle structure and interactions determined by SANSAnkitkumar I.Fajalia,Marina Tsianou ∗Department of Chemical and Biological Engineering,University at Buffalo,The State University of New York (SUNY),Buffalo,NY 14260-4200,United Statesh i g h l i g h t s•CD type and concentration effects onSDS micelle structure and interac-tions are quantified with SANS.•CDs decrease the micelle aggrega-tion number and size,and change the micelle shape from ellipsoid to sphere.•CDs affect the micelle properties directly,by localizing in the micelle,and indirectly,by complexing surfac-tants in the solution.•The effect of ␣-CD on micelle struc-ture is more pronounced at C ␣-CD /C SDS >1.•HP ␤-CD is more effective in influ-encing the micelle structure and interactions compared to ␣-CD.g r a p h i c a la b s t r a cta r t i c l ei n f oArticle history:Received 31July 2014Received in revised form 2December 2014Accepted 7December 2014Available online 2January 2015Keywords:Surfactant MicelleCyclodextrinSmall-angle neutron scatteringa b s t r a c tWe report here the modulating effects of ␣-cyclodextrin (␣-CD)and hydroxypropyl ␤-cyclodextrin (HP ␤-CD)on the self-assembly of a common single-tail surfactant,sodium dodecyl sulfate (SDS),in aqueous solutions.Small angle neutron scattering (SANS)data were fitted using core–shell prolate ellipsoid form factor and Hansen–Hayter-based structure factor to quantify the effects of CD type and concentration on the micelle structure and inter-micellar interactions.The presence of cyclodextrins results in decreased micelle aggregation numbers and sizes,and changes the micelle shape from ellipsoid to sphere.Further,the addition of CD reduces inter-micelle interactions through a decrease of electrostatic coupling.CDs affect the micelle properties directly,by localizing in the micelles,as well as indirectly,by driving sur-factants away from the micelles into the solution due to complexation.The effect of ␣-CD on micelle structure is more pronounced at C ␣-CD /C SDS >1compared to the cases when C ␣-CD /C SDS <1because of the greater number of CD molecules localized in a micelle (directly affecting its structure)and the larger amounts of 2:1CD:SDS complexes in solution (indirectly affecting the micelle structure).Because of its wider cavity and capacity to complex more SDS compared to ␣-CD,HP ␤-CD,primarily forming 1:1CD:SDS complexes,was found more effective in influencing the micelle properties and inter-micelle interactions.To the best of our knowledge,this is the first investigation on the role of cyclodextrins in modulating∗Corresponding author.Tel.:+17166451191.E-mail address:mtsianou@ (M.Tsianou)./10.1016/j.colsurfa.2014.12.0240927-7757/©2015Published by Elsevier B.V.92A.I.Fajalia,M.Tsianou /Colloids and Surfaces A:Physicochem.Eng.Aspects 480(2015)91–104intra-and inter-micelle structure and interactions.These results support the utilization of modulated surfactant self-assembly for applications such as drug delivery and nanoparticle synthesis.©2015Published by Elsevier B.V.1.IntroductionAmphiphilic molecules such as surfactants and block copoly-mers organize themselves in solution to form various nano-structures that find a wide range of applications in, e.g.,detergents,paints,pharmaceutical and agrochemical formulations,and nanoparticle synthesis [1–4].Hydrophobic,electrostatic and/or steric interactions are major driving forces for the self-assembly of amphiphiles in aqueous solution [5,6].Since the interactions involved in surfactant self-assembly are relatively weak compared to chemical bonds,modulation of self-assembly can be readily achieved by varying solvent conditions,e.g.,by changing pH,ionic strength,or temperature,or by adding cosolutes or cosolvents [6–9].Accordingly,the modulation of surfactant self-assembly is an effective and practical approach to manipulate the nanostructure and thereby to develop novel functional materials with desirable properties.Further,it offers a novel route for encapsulation and release of hydrophobic molecules which is useful for delivery appli-cations in the pharmaceutical,agrochemical,food,and household products industries [10,11].Cyclodextrins (CDs)are among the solutes that are known to affect the association of surfactants in aqueous solutions.CDs are toroid-shape supramolecules composed of ␣-D-glucopyranoside units forming a macrocycle ring (Fig.1),and presenting a hydrophilic exterior and a hydrophobic central cavity.The most common CDs are ␣-cyclodextrin,␤-cyclodextrin,and ␥-cyclodextrin which consist of six,seven,and eight glucopyranoside units,respectively.Cyclodextrins and their derivatives find a num-ber of applications in the pharmaceutical,cosmetic,and food industries for encapsulation of hydrophobic or volatile actives,in analytical chemistry as separating agents,and in catalysis [12–17].Fig.1.Chemical structure,geometry,and dimensions of ␣-and ␤-cyclodextrins.Because of the hydrophobic nature of the cavity of the CD molecules,the water-insoluble “tail”of a surfactant molecule may partition inside this cavity compared to the aqueous media.Depending upon the size of the CD cavity and the chemical nature of the surfactant,a variety of complexes may form,the stoichiometry of which,e.g.,1:1(one CD molecule per one surfactant molecule),2:1,etc.,has been inferred on the basis of results from conductivity,electrochemical or other methods [18–26].While the complexation of cyclodextrins with surfactant molecules at surfactant concentrations lower than the critical micelle concentration (CMC)has been reported in the literature [18,23,27,28],the effects of cyclodextrins at higher surfactant concentration have remained largely unexplored.Several key ques-tions remain open:Do cyclodextrins affect the micelle size,shape,and inter-micelle interactions?If yes,by what mechanism?Do cyclodextrins participate in the micelles and affect the micelle structure directly,or do they prefer to stay in the solution and affect the micelle structure indirectly?Some studies have attempted to address these questions;nev-ertheless,the possible partitioning of cyclodextrin in the micelles remains ambiguous.Reports based on speed of sound mea-surements [29],NMR diffusivity measurements [30,31],reaction kinetic measurements using hydrophobic probes [32],and fluo-rescence quenching measurements on micelles [20]indicate no participation of cyclodextrins in the surfactant micelles.How-ever,other reports support partitioning of CDs in micelles.A recent investigation suggested the adsorption of unsubstituted and methylated cyclodextrins on sodium decanoate micelles,indicat-ing that methylated cyclodextrins localize in the micelle shell [33].Another study reported the formation of mixed ␤-CD and sodium dodecyl sulfate (SDS)micelles below the CMC,and suggested the incorporation of CDs inside the micelles [34].Rheological mea-surements in aqueous solutions of SDS associated with oppositely charged polyelectrolytes supported the localization of CD–SDS complexes in the micelles that form crosslinks between the poly-electrolyte chains [17].Calorimetric studies have shown favorable interactions between HP ␣-CD and micelles of ionic surfactants and have indicated the possibility for localization of cyclodextrins in the micelle “Palisade layer”[35,36].We have addressed the questions about CD effects on micelles using small angle neutron scattering (SANS).SANS has been utilized to characterize SDS micelles in aqueous solutions,in the absence or presence of salt with different counterions [37–44].However,SANS investigations of SDS in the presence of CDs have not been previ-ously reported.In a recent study [45],we have probed the location of cyclodextrins (native/modified)in SDS micelles using SANS with contrast matched SDS.Contrast matching can provide structural information on a part of an overall structure by selectively deuter-ating the remaining part of such structure in order to match its scattering to that of the deuterated solvent.We have thus estab-lished the localization of a fraction of CDs in the SDS micelles [45].Here,we employ SANS to investigate the effect of cyclodextrins on SDS micelle structure and interactions in aqueous solutions.We have considered two different types of CDs,␣-cyclodextrin (␣-CD)and hydroxypropyl ␤-cyclodextrin (HP ␤-CD).We have examined solutions with similar CD/SDS ratios at two different surfactant concentrations.We fitted the SANS data using core–shell prolate ellipsoid form factor and Hansen–Hayter-based structure factor to determine micelle composition,structure,and inter-micelle inter-actions in the absence and in the presence of CDs.To the best of ourA.I.Fajalia,M.Tsianou/Colloids and Surfaces A:Physicochem.Eng.Aspects480(2015)91–10493knowledge,this is thefirst SANS investigation on the role of CDs in modulating SDS micelle structure and interactions.2.Materials and methods2.1.MaterialsHydrogenous sodium dodecyl sulfate(SDS)was obtained from Sigma,while deuterated sodium dodecyl sulfate (CD3(CD2)11OSO3Na)(D25,98%)and heavy water(D2O)were purchased from Cambridge Isotope Laboratories,Tewksbury, MA.␣-Cyclodextrin and2-hydroxypropyl-␤-cyclodextrin were purchased from Aldrich.HP␤-CD has been used in the present study due to its higher aqueous solubility compared to␤-CD.The degree of substitution of hydroxypropyl groups for␤-cyclodextrin was specified as4.3by the supplier.All chemicals were used as received.The deuterated chemicals were stored in a desicca-tor or ampoules to prevent contamination with H2O from the atmosphere.Stock solutions of surfactant and of CD in D2O werefirst pre-pared and then mixed in appropriate ratios with D2O and with each other to obtain the desiredfinal concentration.Adequate time for equilibration was allowed.The relative ratio of the binding constants for CD–SDS multiple equilibria suggest that␤-CD pri-marily forms1:1inclusion complexes with SDS.However,for␣-CD and SDS aqueous solutions,along with1:1complexes,2:1com-plexes are also present in significant amounts depending on the concentration of CD relative to the surfactant[23].Hence in order to achieve1:1or2:1stoichiometric ratios of␣-CD with respect to HP␤-CD,samples were prepared with␣-CD concentrations either equal or double the concentration of HP␤-CD in aqueous solutions at a given surfactant concentration.The␣-CD concentration var-ied from0mM to50mM keeping SDS at either25mM or50mM. Similarly,the HP␤-CD concentration varied from0mM to30mM with SDS concentration of25mM or50mM.The CD concentrations were selected such that comparable C CD/C SDS ratios are attained.2.2.SANS data collection and reductionSANS measurements were performed on the30m spec-trophotometer(NG3)at the National Institute of Standards and Technology(NIST),Gaithersburg,MD.Neutrons with wavelength of6˚A and wavelength spread / of14.3%were focused on the sample kept in4mm quartz cell at25±0.1◦C.A sample to detector distance of2m was used that covered the wave vec-tor q range0.01˚A−1<q<0.3˚A−1.The beam time was between 180s and4800s for each measurement.Scattering data were corrected for the scattering from background,empty cell and detector sensitivity.Absolute scale intensity was obtained fol-lowing standard procedures[46].Absolute intensity data were then corrected for incoherent solvent scattering,and the reduced SANS data werefitted using a non-linear least square method with Levenberg–Marquardt algorithm in order to obtain physically appropriate values of thefitting parameters.3.Small angle neutron scattering(SANS)data analysisThe overall scattering intensity I(q)from SDS aqueous solutions is given by Eq.(1):I(q)=Scale· ·P(q)·S(q)+Background(1) The form factor P(q)represents the shape and structure of a micelle,while the structure factor S(q)captures the inter-micelle interactions and overall arrangement of micelles in the solution. is the volume fraction of the micelles which in turn depends onthe Fig.2.Prolate core–shell ellipsoid model of an SDS micelle consisting of a core with a major axis a and a minor axis b,and a shell of thicknessı. 1, 2and S are the scattering length densities of the core,shell,and solvent,respectively. 0is the equivalent spherical diameter of the ellipsoid.overall surfactant concentration.The parameters Scale and Back-ground take into account additional contributions associated with absolute scaling and incoherent noise,respectively.We considered the micelles as monodispersed prolate ellipsoids with core–shell structure as shown in Fig.2,where the micelle core consists of alkyl tails and small amount of cyclodextrins[45],while the micelle shell comprises of surfactant head groups,counterions, and associated water molecules.P(q)was calculated using equations(2)and(3)[43,47]:P(q)=1V TOT1|F(q,a,b,ı,ˇ)|2dˇ(2) F(q,a,b,ı,ˇ)=V C( 1− 2)3j1(u C)u C+V TOT( 2− S)3j1(u T)u T(3)Thefirst term in Eq.(3)represents scattering due to the core of the micelle having core volume V C=(4 /3)ab2,where a is the major and b the minor core radius.The second term in Eq.(3)is the scattering due to the shell region(with constant thicknessı) of a micelle with total volume V TOT=(4 /3)(a+ı)(b+ı)2. 1, 2 and S are the scattering length densities of micelle core,shell, and solvent,respectively.j1(u)denotes thefirst order spherical Bessel function of thefirst kind,j1(u i)=(sin u i−u i cos u i)/u i2,where u i=q[a i2ˇ2+b i2(1−ˇ2)]1/2.The subscripts i=C or i=T denote micelle core or whole micelle including the shell.ˇ=cos ,where is the angle at which the major axis is inclined to the scattering vector q.The structure factor S(q)was calculated using the Hansen–Hayter potential[48,49],with mean spherical approxima-tion and rescaling corrections for low volume fractions,given the micelle volume fraction,charge on a micelle,and ionic strength of the solution.In this model,micelles are approximated as charged spheres of diameter interacting through screened Coulombic potential(Yukawa potential)[48].The majorfitting parameters are the surfactant aggregation numberÁ(number of surfactant molecules per micelles)and the94 A.I.Fajalia,M.Tsianou/Colloids and Surfaces A:Physicochem.Eng.Aspects480(2015)91–104Table1Concentrations of uncomplexed SDS,uncomplexed␣-CD,1:1and2:1CD–SDS complexes,and the fraction, ,of1:1complexes present in the aqueous solution at equilibrium.aC SDSi(mM)C CDi(mM) C SDSeq(mM)C CDeq(mM)C S-CDeq(mM)C S-CD2eq(mM)12.550.628.470.017 3.070.9625100.6216.930.017 6.15 1.9225200.4310.770.0388.49 5.7425320.26 4.920.0808.2411.8450200.6233.850.01712.31 3.8450400.4321.530.03816.9911.4950500.3516.250.05117.5316.21a CSDSiis the total surfactant concentration,C CDi is the total cyclodextrin concentration,C SDSeq is the equilibrium concentration of uncomplexed SDS,and C CDeq is the equilibrium concentration of uncomplexed cyclodextrin.C S-CDeq is the equilibrium concentration of1:1CD–SDS complexes,and C S-CD2eq is the equilibrium concentration of 2:1CD:SDS complexes.The equilibrium concentrations and values were calculated by solving simultaneously equilibrium and mass balance equations[45].fraction of CDs going to micelles ,primarily influencing the formfactor,and the charge on a micelle Z which affects the structure fac-tor.The fraction of1:1CD–SDS complexes was calculated witha procedure described in reference[45]that considered the multi-ple equilibria between uncomplexed␣-CD,uncomplexed SDS,and1:1and2:1CD–SDS complexes,and solved for the various concen-trations using the equilibrium constants K1and K2reported in theliterature for␣-CD–SDS binding.The equilibrium constants,K1andK2,utilized in the present study were obtained from the CD–SDSbinding studies by Yunus et al.[23]who utilized electromotive forcemeasurements with surfactant ion-selective electrode.Values offor different surfactant solutions in the presence of␣-CD are shownin Table1. wasfixed at1for HP␤-CD since it forms mostly1:1type inclusion complexes with SDS.With known molar concentrations of the surfactant C SDSand cyclodextrins C CD,the micelle number density N P(num-ber of micelles per unit volume,Å3)was calculated fromN P=[C SDS−(C CD(1− )(1+ )/2)](N Av×10−30/Á)where N Avis Avogadro’s number.The aggregation number of CDs,k(number of CD molecules per micelle)was calculated usingk=(Á C CD)/(C SDS−(C CD(1− )(1+ )/2)).The effective CMC valueswere calculated using the relation C CMCeff=((C CD(1− )(1+ ))/2)at a given total cyclodextrin concentration C CD,the fraction ofcyclodextrins participating in micelles (obtained from thedatafitting),and the fraction of1:1and2:1type complexes(obtained by considering CD–SDS multiple equilibria)[45].The micelle core volume V C(Å3)was calculated given theaggregation numbers for surfactants and cyclodextrin usingV C=[Á−(k(1+ )/2)]Vt SDS+(k(1+ )/2)Vt Complex,where Vt SDS isthe volume of a single alkyl chain of a surfactant molecule,andVt Complex is the volume of a CD–SDS complex with length that ofan alkyl chain and diameter the same as the cyclodextrin exteriordiameter.Vt SDS was calculated using Vt SDS=27.4+26.9N CT,whileVt Complex was calculated from Vt Complex=( D CDout2b)/4whereD CDout is the exterior diameter of the CD molecule(see Fig.1).The micelle core radius b wasfixed at16.7˚A,considering a fullystretched alkyl chain of12carbon atoms.The major core radiusa was determined from the core volume using a=3V C/4 b2.Themajor to minor core radius axis ratio a/b is denotedε.The totalvolume of a micelle was calculated from the core volume V C andthe shell volume V Shell considering volume contributions fromhead groups,counterions and water molecules present in the shellusing V TOT=Á[V OSO−3+(1−˛)V Na++N H V D2O]+V C,where˛isthe fractional charge on a micelle defined as Z/Á.N H is the hydration number(number of water molecules associated with a surfactanthead group)and isfixed at N H=12[45].VOSO−3,V Na+and V D2Oare molecular volumes of surfactant head groups,counterions, and deuterated water molecules,respectively.The shell thickness ıwas calculated iteratively from4 (a+ı)(b+ı)2/3=V TOT.The equivalent spherical diameter 0of a micelle was calculated from 0=2[(ab2)1/3+ı].The scattering length densities of the core 1and shell 2were calculated by addition of scattering length con-tributions of the groups/atoms present and the molecular volumes of the core V C and the shell V Shell respectively. The scattering length density of the solvent Solvent was calculated using S=[(( massD2O×106b D2O)/MW D2O)+(((1+ )(1− )C CD b SDS)/2)+(1− )C CD b CD]N Av×10−30to include scattering contributions from cyclodextrin and surfactant molecules present in D2O.The major contribution to the overall scattering intensity comes from the contrast between the micelle core(consisting of hydrogenated surfactant tails and cyclodextrins)and the solvent. For SDS in D2O,a typical value of scattering length density for the micelle core is 1=−3.90×10−7(Å−2),for the micelle shell is 2∼6.13×10−6(Å−2),and for solvent is S=6.34×10−6(Å−2). The micelle volume fraction was calculated using =N P V TOT.The quality of thefits was attested by correlation coefficient R2values >0.98and by root mean square errors lower than0.012.4.Results and discussion4.1.SDS micelles in D2OWefirst discuss structure and interactions of SDS micelles in D2O in order to establish the base case for subsequent comparison with systems containing cyclodextrins.SANS profiles at different SDS concentrations in D2O are shown in Fig.3.The scattering inten-sity is not significant for the case of8.9mM SDS which is near the CMC,however,with an increase in SDS concentration,micelles grow in number and size as attested by higher overall scatter-ing intensity,and the development of a pronounced correlation peak.The position of the correlation peak maximum reflects the inter-micelle distance(d=2 /q max)and the sharpness of the peak indicates the strength of the interactions(long range electrostatic repulsion)between the micelles[33].An increase in the surfac-tant concentration leads to an increase in q max and a decrease in the inter-micelle spacing.Since the micelle number density N P(number of micelles per unit volume)depends on the inter-micelle distance as N P∼1/d3,an increase in d suggests higher micelle number densities with increase in surfactant concentra-tion.Accordingly,the surfactant aggregation number[estimated from N P=(C SDS−C CMC)(N Av×10−30/Á)]should also increase.At q values higher than the inverse of the smallest micelle dimension,in our case0.14≤q≤0.22,the Porod equation I(q)=2 2(S/V)q−4can befitted to the experimental data to extract the value of surface-to-volume ratio S/V for the total surfactant in the solution,given the value of the scattering con-trast between the micelle core and solvent ,−6.73×10−6 (Å−2)(assuming negligible scattering contrast between micelle shell and solvent)[33].The average surface area per micelle S micelle can be estimated from the S/V ratio using the relation S micelle=(S/V)x micelle/N P,where x micelle is the fraction of the micellesA.I.Fajalia,M.Tsianou /Colloids and Surfaces A:Physicochem.Eng.Aspects 480(2015)91–104952.52.01.51.00.50.0I n t e n s i t y I (q ) (c m -1)0.300.250.200.150.100.05q (Å-1)0.000 10.00 10.010.11I n t e n s i t y I (q ) (c m -1)0.010.1q (Å-1)1.21.00.80.60.40.20.0S t r u c t u r e f a c t o r S (q )0.200.150.100.050.00q (Å-1)Fig.3.SANS intensity profiles from SDS solutions in D 2O at different SDS concen-trations,plotted in (a)linear and (b)logarithmic scale,where markers representexperimental data and solid lines represent fits to the core–shell prolate ellipsoid form factor and Hansen–Hayter-based structure factor.(c)Structure factor for SDS micelles in D 2O extracted from the fittings to SANS data.in the system estimated by x micelle =(C SDS −C CMC )/C SDS ,and N P is themicelle number density.Upon addition of up to 100mM SDS,theestimated average surface area per micelle increased to 8594˚A−2which is ∼80times the micelle surface area found at 8.9mM SDS.The experimental SANS data were fitted with the form and struc-ture factors described in Section 3.Extracted fitting parameters and other derived quantities are shown in Table 2.As the surfactant concentration C SDS increases from 8.9mM to 100mM,the aggre-gation number increases by 54%from its initial value of 61.8at the CMC (see Table 2).The surfactant concentration dependenceof the aggregation number,depicted in Fig.4,follows the relation-ship Á∝C SDS which is in agreement with the ladder model for surfactant micellization [44].10090807060A g g r e g a t i o n n u m b e r η10080604020C SDS (mM )Fig.4.Micelle aggregation number plotted as a function of surfactant concentrationfor SDS in D 2O.The aggregation numbers ()were extracted by fitting to SANS data the core–shell prolate ellipsoid form factor and Hansen–Hayter-based structure factor as described in the text.The solid line represents a power law fit to the data:Á=Á0+c 1C pSDS .The fitted value of exponent p is 0.50and the aggregation number at the CMC ÁCMC is 61.8.The surface area per micelle increases with surfactant concen-tration (Fig.5top),however,the average surface area per surfactantmolecule in a micelle decreases from 97.7˚A−2(at 8.9mM SDS)to 88.3˚A−2at 100mM SDS.The increase in surface area per micelle implies a growth of the micelle size,while the decrease in the surface area per surfactant is an indication of a denser surfactant packing at the micelle surface.Since the surfactant packing density cannot increase much,addition of more surfactant molecules in a micelle will result in an increase in the anisotropy of the micelles.As shown in Table 2,the ratio of major to minor micelle core axis100969288S u r f a c e a r e a /h e a d g r o u p (Å2)10080604020C SDS (mM )850080007500700065006000Surface area/micelle (Å2)5004003002001000D e b y e l e n g t h κ-1(Å)10080604020C SDS (mM )0.550.500.450.400.350.300.25Coupling constant ΓkFig.5.Variation in SDS micelle parameters with surfactant concentration:[top]surface area per surfactant head group (᭹)and total surface area per micelle ( );[bottom]Debye length ( )and electrostatic coupling constant ( ).The parameters were extracted by fitting SANS data with the core–shell prolate ellipsoid form and Hansen–Hayter-based structure factor as described in the text.96A.I.Fajalia,M.Tsianou /Colloids and Surfaces A:Physicochem.Eng.Aspects 480(2015)91–104Table 2Parameters describing the micelle structure obtained by fitting SANS data of SDS in D 2O using the form and structure factors described in the text.aC SDS (mM)ÁZN P (Å−3)a (Å)εı(Å)0(Å)S micelle (Å−2)S surfactant (Å−2)8.961.8(±0.1)7.6(±1.1)8.77E −0918.6 1.11 4.5843.76041.897.7 5.2115.067.0(±0.1)8.1(±0.3) 6.31E −0820.1 1.21 4.7044.96409.695.7 3.4019.969.7(±0.3)8.5(±0.2) 1.03E −0720.9 1.25 4.7645.56600.294.7 3.6924.872.5(±0.1)9.6(±0.1) 1.40E −0721.8 1.30 4.8146.16798.193.8 4.4233.375.0(±0.1)10.4(±0.1) 2.03E −0722.5 1.35 4.8646.66975.493.018.6249.880.1(±0.1)13.3(±0.1) 3.14E −0724.0 1.44 4.9447.67334.691.6 6.71100.094.9(±0.1)17.7(±0.1)5.84E −0728.51.715.1650.28381.788.35.38aÁis the aggregation number (number of surfactant molecules per micelle)and Z is the charge on a micelle.Áand Z are the main fitting parameters,while all the other parameters are calculated from these.N P is the number density of micelles,˛is the micelle core minor axis,εis the ratio of major to minor micelle core axis,ıis the shell thickness, 0is the equivalent spherical diameter of a micelle,S micelle is the total surface area of a micelle,and S headgroup is the surface area per surfactant head group in amicelle.Reduced values [54]were calculated using =1/(N −N p +1)Ni =1[(y i −y m i )/ i ]2where y i is the experimental data point,y mi is the model prediction, i is thestandard deviation of the measurement,N is the number of data points,and N P is the number of fitting parameters.Values of errors in the fitting parameters are shown inparenthesis in italics .increases from 1.1to 1.7with increasing surfactant concentration,indicating a gradual shape transition from sphere to ellipsoid.The volume fraction of the micelles increases linearly with the surfactant concentration.The micelle number density increases monotonically with the surfactant concentration (Table 2)which indicates the formation of new micelles that are spaced closer.In addition to their increasing number,micelles grow in their sizes,and,correspondingly,the inter-micelle distances decrease,result-ing in stronger interactions between the micelles.Further,the fractional charge on a micelle ˛increases from 0.12to 0.18follow-ing an increase in surfactant concentration from 8.9to 100mM,which reflects higher dissociation of the counterions from the sur-factant head groups present in a micelle,increasing the overall charge on the micelle.A higher dissociation increases the counter-ion concentration in the solution and thus decreases the Debye length for the charged micelles as shown in Fig.5(bottom)allowing micelles to pack more densely.The coupling constant k (ratio of Coulombic energy to the thermal energy at inter-micelle distance)increases with increasing surfactant concentration as shown in Fig.5(bottom),which further quantifies higher electrostatic inter-actions between micelles.Because of the stronger interactions and smaller inter-micelle distances,the micelles arrange themselves in a more organized fashion,which is reflected in more pronounced periodic oscillations in the structure factor (Fig.3c).The isothermal compressibility of the micelles,defined as S (q )at q →0,decreases with surfactant concentration allowing the micelles to come closer toward more lattice-like structure.The increase in SDS micelle size and aggregation number,and change in micelle shape upon surfactant addition that is observed here are consistent with what has been reported in the litera-ture [37–44,47,50,51].Similarly,stronger interactions,higher total micelle charge,and reduction in isothermal compressibility with increasing surfactant concentration have also been reported in the literature [52].4.2.Effect of ˛-cyclodextrin on SDS micelle composition,structure,and interactionsA reduction in the overall scattering intensity and a broadening of the correlation peak (Fig.6)is observed upon addition of ␣-CD in the SDS aqueous solution,reflecting a shift in the distribution of surfactants from the micelles into the solution.Such trends are sim-ilar to the case of SDS concentration decrease in the absence of any CD (Fig.3).The decrease in scattering intensities with increasing CD concentration at a fixed SDS concentration indicates a reduction in the micelle dimensions and repulsion associated with a drop in the aggregation number and charge on a micelle.On the other hand,the peak position q max remains unaffected by the addition of ␣-CD,indicating minor changes in the inter-micelle distance d (Fig.7).At any ␣-CD concentration,the d values for 25mM SDS are higher than those at 50mM SDS due to lower micelle number densities at the lower SDS concentration.The micelle structure and interac-tion parameters obtained from fits of SANS data are presented in Table 3.The CMC of the system increases with ␣-CD concentration (C ␣-CD )(Fig.7),as the surfactant molecules that form inclusion complexes with ␣-CDs have lower hydrophobicity.A CMC increase upon cyclodextrin addition to SDS aqueous solution has been observed by other experimental methods [20,28,53].The CMC in the presence of ␣-CD remains unaffected (at 8mM)up to a CD molar concentration of about double the surfactant CMC (∼16mM),related to the formation of 2:1complexes in the solution.Above C CD >16mM,the slope of increase in CMC with respect to CD concen-tration is ∼0.5mM SDS/mM C ␣-CD at both 25mM and 50mM SDS cases.This slope value suggests the solubilization of 1mole of sur-factant per 2␣-CD moles,which is consistent with the formation of 2:1type ␣-CD–SDS complexes.The amount of surfactant participating in the micelles will be (C SDS −CMC eff )mM in the presence of cyclodextrins since CMC eff indicates the amount of surfactant remaining in the solution pseudo-phase.In the absence of CDs,the amount of surfactant par-ticipating in the micelles will be (C SDS −8)given CMC =8mM for aqueous SDS parison of parameters for SDS solutions suggest an increase in micelle number densities and a reduction in surfactant aggregation numbers in the presence of CD com-pared to the SDS micelles in the absence of CD.For example,in the case of 20mM ␣-CD added to 25mM SDS in D 2O,CMC eff increases to 12.6mM (from CMC =8mM when no CDs are present),which results in similar amount of surfactant participating in micelles as a 20mM SDS solution in the absence of parison of scattering profiles from solutions containing similar amounts of surfactants in the micelles,either in the presence of ␣-CD or in the absence (Figs.3and 6),indicates broader peaks and lower peak intensities in the scattering profiles of solutions containing CDs.The aggregation number for SDS micelles at 20mM SDS in the absenceof ␣-CD is 69.7and the number density is 1.03E −7˚A3(Table 2),while for 25mM SDS solution in the presence of ␣-CD (20mM),the aggregation number is lower (46.5)and the number density higher(1.61E −7˚A3)(Table 3)compared to the SDS solutions having sim-ilar amounts of surfactants participating in the micelles.Similarly,the amount of surfactant participating in micelles from 50mM SDS solutions in the presence of 40mM ␣-CD is equivalent to that of 37mM SDS in the absence of CD.The aggregation number in the presence of ␣-CD is 40.1,much lower than the aggregation number (>75)found at 33mM SDS in D 2O.The micelle number density increases compared to that in the absence of CD (by ∼15%for the case of 25mM SDS and 39%for the case of 50mM SDS)when the molar ratio of ␣-CD to SDS is less。

科技报告导读科技创新导报 Science and Technology Innovation Herald 173焦虑与抑郁的神经环路和分子机制罗敏敏 张二荃 占成(北京生命科学研究所)摘 要：焦虑和抑郁症是人群中最常见的情绪和情感障碍，而情绪和情感的神经机制是公认的重大科学问题之一。

该研究利用小鼠作为模式动物，研究焦虑和抑郁症的神经环路和分子机理这个关键科学问题，通过多学科交叉，分为3个研究展开，试图从分子到个体多层次研究焦虑和抑郁症行为的神经生物学机制。

该研究第一个子研究是动物焦虑和抑郁行为的细胞生理学研究。

五羟色胺(5-HT)系统紊乱会导致焦虑、快感缺失和抑郁，而且5-HT转运体是现有的治疗抑郁的主要靶点，因此，在第一个子研究中，研究组成员研究了激活脑内5-HT主要来源的背侧中缝核(DRN)5-HT细胞的行为效果。

通过运用光遗传学、清醒动物单细胞记录、药理学、转基因小鼠遗传操作以及多种行为学分析，发现激活DRN的5-HT细胞产生强烈的奖赏效应，而且此一效应通过5-HT以及谷氨酸这两种神经递质来完成。

这些结果证明中缝背核直接介导奖赏效应，而且为从多神经递质的角度分析中缝背核的功能提供了良好的开端；为快感缺失及其相关的抑郁、精神分裂等情绪紊乱和精神疾病症候群的机理和治疗揭示了新的途径。

该研究第二个子研究主要研究生物节律对人类情绪等行为的影响。

生物节律包括近日节律(昼夜)、近月节律（潮汐）、近年节律（季节）等等周期在生物体内的表征。

我们重点研究对象是近日周期、近年周期，与人类情绪调控的互作。

该年度报告中，主要在3个方面有明显进展：(1)近年节律对情绪调控的影响方面，我们发现小鼠C3H品系对于模拟人类季节性抑郁症方面有较好的吻合；(2)近日节律对情绪调控的影响方面，我们发现VTA脑区的生物钟基因Bmal1和Clock都有很重要的作用；(3)药物治疗方面，我们运用高通量方面对约9 000个化合物进行了筛选，找到了一批生物钟调节相关的化合先导物，可能为通过对生物钟进行调节进而缓解人类情绪疾病提供一种崭新的尝试。

第 3 期第 158-165 页材料工程Vol.52Mar. 2024Journal of Materials EngineeringNo.3pp.158-165第 52 卷2024 年 3 月冷轧压下率对高强无取向电工钢变形组织和磁性能的影响Effect of cold rolling reduction rate on deformation microstructure and magnetic properties of high strength non -oriented electrical steel吴硕，贾涓*，宋新莉，程朝阳，吴隽，刘静（武汉科技大学 省部共建耐火材料与冶金国家重点实验室，武汉 430081）WU Shuo ，JIA Juan *，SONG Xinli ，CHENG Zhaoyang ，WU Jun ，LIU Jing（The State Key Laboratory of Refractories and Metallurgy ，Wuhan University of Science and Technology ，Wuhan 430081，China ）摘要：借助场发射扫描电镜（SEM+EBSD ）、快速升温管式炉和交流磁性能测量仪研究高强无取向电工钢冷轧变形组织和磁性能随冷轧压下率的变化规律。

结果表明：冷轧高强无取向电工钢中形成含有大量亚结构的粗糙条带和变形量较小的光滑条带。

粗糙条带具有γ取向，主要为｛111｝〈110〉，光滑条带具有｛112｝〈110〉和｛001｝〈110〉取向。

粗糙条带中存在大量宽度约为2~3 μm 的剪切带，与轧向呈20°~35°夹角，且随压下率增大，数量逐渐增多。

剪切带与基体间具有一定取向差，随压下率增大，剪切带逐渐从｛111｝〈110〉取向转向｛223｝〈110〉取向，与基体间取向差逐渐增大。

退火后Goss 和｛111｝面织构增多，｛001｝面织构减少；轧向磁感应强度增大，横向磁感应强度减小，各向异性显著，铁损下降。

邹宇欣，谢静雯，王洪涛，等. 超声对动物蛋白结构及性质影响研究进展[J]. 食品工业科技，2024，45（9）：399−409. doi:10.13386/j.issn1002-0306.2023060247ZOU Yuxin, XIE Jingwen, WANG Hongtao, et al. Research Progress on the Effect of Ultrasound on Animal Protein Structure and Properties[J]. Science and Technology of Food Industry, 2024, 45(9): 399−409. (in Chinese with English abstract). doi:10.13386/j.issn1002-0306.2023060247· 专题综述 ·超声对动物蛋白结构及性质影响研究进展邹宇欣1，谢静雯1，王洪涛1，吴　越1，刘嘉涵1，刘思琦1，王跃猛2，李　鑫1,*（1.烟台大学生命科学学院，山东烟台 264005；2.烟台理工学院食品与生物工程学院，山东烟台 264003）摘　要：动物性蛋白主要来源于禽、畜及鱼类等的肉、蛋、奶。

动物蛋白营养价值高且应用广泛，但天然动物蛋白质的功能特性通常不能完全满足工业要求。

超声作为一项非热加工物理处理技术，它会导致动物蛋白理化性质及结构变化从而改善功能特性。

但目前关于超声对各种动物蛋白影响的联系和区别尚待研究。

因此，为明确超声处理对动物蛋白结构和性质的影响以及各自之间的联系和区别，本文主要从超声功率、超声时间和动物蛋白种类出发，对动物蛋白的理化性质、微观结构、界面性质和功能性质分别进行综述，解析了动物蛋白理化性质及微观结构的变化与其界面性质和功能性质的变化之间的关系，并对超声处理对动物蛋白的应用进行了讨论和展望，以期为后续超声处理在动物蛋白的应用和推广提供理论参考。