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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.。
