A Study of the Thermal Characteristics of NiCuZn Ferrite Chip Inductors

Symbol V DS V GSI DM I AR E AR SymbolTyp Max 16.7254050R θJC23Continuous Drain B,HUnits Parameter T C =25°C T C =100°CAbsolute Maximum Ratings T A =25°C unless otherwise noted V T A =70°C Power Dissipation B Avalanche CurrentC Repetitive avalanche energy L=0.1mH C ID Pulsed Drain Current CVGate-Source Voltage Drain-Source Voltage Steady-StateT A =25°C P DSM T C =25°C Maximum Junction-to-Ambient A,G Steady-State Power Dissipation AP D T C =100°C °C/WThermal CharacteristicsParameterUnits Maximum Junction-to-Ambient A,Gt ≤ 10sR θJA °C/W °C/W Maximum Junction-to-CaseFGS DGSDSymbolMin TypMaxUnits BV DSS -40V -1T J =55°C-5I GSS ±100nA V GS(th)-1.7-2-3V I D(ON)-30A3644T J =125°C52655266g FS 22S V SD -0.76-1V I S-12A C iss 9001125pF C oss 97pF C rss 68pF R g14ΩQ g (-10V)16.221nC Q g (-4.5V)7.29.4nC Q gs 3.8nC Q gd 3.5nC t D(on) 6.2ns t r 8.4ns t D(off)44.8ns t f 41.2ns t rr 21.2ns Q rr13.8nC -20COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS ARE NOT AUTHORIZED. AOS DOES NOT ASSUME ANY LIABILITY ARISING OUT OF SUCH APPLICATIONS OR USES OF ITS PRODUCTS. AOS RESERVES THE RIGHT TO IMPROVE PRODUCT DESIGN,FUNCTIONS AND RELIABILITY WITHOUT NOTICE.20Gate Source Charge Gate resistanceV GS =0V, V DS =0V, f=1MHzV GS = -10V, V DS = -20V,I D = -12ATotal Gate Charge m ΩTurn-On Rise Time Turn-Off DelayTime V GS = -10V, V DS = -20V, R L =1.6Ω,R GEN =3ΩTurn-Off Fall TimeTurn-On DelayTime Gate Drain Charge V GS =0V, V DS = -20V, f=1MHz SWITCHING PARAMETERS Total Gate Charge V GS = -4.5V, I D = -8AI S = -1A,V GS =0VV DS = -5V, I D = -12A Maximum Body-Diode Continuous CurrentInput Capacitance Output CapacitanceDYNAMIC PARAMETERS R DS(ON)Static Drain-Source On-ResistanceForward Transconductance Diode Forward VoltageElectrical Characteristics (T J =25°C unless otherwise noted)STATIC PARAMETERS ParameterConditions I DSS µA Body Diode Reverse Recovery Charge I F = -12A, dI/dt=100A/µsBody Diode Reverse Recovery TimeV GS = -10V, I D = -12AReverse Transfer Capacitance I F = -12A, dI/dt=100A/µsGate Threshold Voltage V DS =V GS I D = -250µA Drain-Source Breakdown Voltage On state drain currentI D = -250µA, V GS =0V V GS = -10V, V DS = -5V V DS = -40V, V GS =0VV DS =0V, V GS = ±20V Zero Gate Voltage Drain Current Gate-Body leakage current A: The value of R θJA is measured with the device in a still air environment with T A =25°C. The power dissipation P DSM and current rating I DSM are based on T J(MAX)=150°C, using t ≤ 10s junction-to-ambient thermal resistance.B. The power dissipation P D is based on T J(MAX)=175°C, using junction-to-case thermal resistance, and is more useful in setting the upper dissipation limit for cases where additional heatsinking is used.C: Repetitive rating, pulse width limited by junction temperature T J(MAX)=175°C.D. The R θJA is the sum of the thermal impedence from junction to case R θJC and case to ambient.E. The static characteristics in Figures 1 to 6 are obtained using <300 µs pulses, duty cycle 0.5% max.F. These curves are based on the junction-to-case thermal impedence which is measured with the device mounted to a large heatsink, assuminga maximum junction temperature of T J(MAX)=175°C. The SOA curve provides a single pulse ratin g.G. These tests are performed with the device mounted on 1 in 2 FR-4 board with 2oz. Copper, in a still air environment with T A =25°C.H. The maximum current rating is limited by bond-wires.*This device is guaranteed green after data code 8X11 (Sep 1ST 2008).Rev4: April 2011VdsChargeGate Charge Test Circuit & WaveformVddVdsIdVgsUnclamped Inductive Switching (UIS) Test Circuit & Waveforms2E = 1/2 LI AR ARBV DSSI ARVdd VddResistive Switching Test Circuit & Waveforms90%10%。

机械工程英语试题及答案一、单项选择题（每题2分，共20分）1. The term "mechanical engineering" refers to the field of study that involves the application of principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems.A. TrueB. False答案：A2. Which of the following is not a sub-discipline of mechanical engineering?A. RoboticsB. ThermodynamicsC. Civil EngineeringD. Materials Science答案：C3. The process of converting a design into a physical object is known as:A. PrototypingB. DesignC. AnalysisD. Manufacturing答案：D4. In mechanical engineering, what does the acronym "CAD" stand for?A. Computer Aided DesignB. Computer Aided DraftingC. Computer Aided DevelopmentD. Computer Aided Drawing答案：A5. What is the primary function of a bearing in a mechanical system?A. To reduce frictionB. To increase frictionC. To absorb shockD. To generate heat答案：A6. The study of heat transfer, thermal energy storage, and the effects of temperature on materials is known as:A. ThermodynamicsB. Fluid MechanicsC. Heat TransferD. Materials Science答案：C7. What is the SI unit for power?A. WattB. JouleC. NewtonD. Pascal答案：A8. A gear system that uses two or more gears to transmit motion and force is called:A. GearboxB. Pulley systemC. Cam mechanismD. Lever system答案：A9. In mechanical engineering, what does the term "stress" refer to?A. Force per unit areaB. Strain per unit forceC. Force per unit volumeD. Strain per unit volume答案：A10. Which of the following is a type of energy storage device used in mechanical systems?A. SpringB. BatteryC. CapacitorD. Inductor答案：A二、填空题（每题2分，共20分）1. The ________ of a material is its ability to resist deformation under applied force.答案：stiffness2. The ________ of a material is its ability to resist breaking under stress.答案：strength3. In a four-stroke internal combustion engine, the ________ stroke is where the fuel-air mixture is compressed.答案：compression4. A ________ is a mechanical device that converts rotational motion into linear motion.答案：screw5. The ________ of a system is the total energy required to produce the system.答案：embodied energy6. A ________ is a type of simple machine consisting of a wheel and a rope wrapped around it.答案：pulley7. The ________ of a system is the energy required to operate the system over its lifetime.答案：operational energy8. A ________ is a type of energy storage device that uses the elastic properties of materials to store energy.答案：spring9. The ________ of a material is its ability to resist deformation under stress.答案：ductility10. A ________ is a type of energy storage device that uses the potential energy of a raised mass to store energy.答案：gravity storage system三、简答题（每题10分，共40分）1. Explain the difference between static and dynamic equilibrium in mechanical systems.答案：Static equilibrium refers to a state where all forces and moments acting on a system are balanced, resulting in no acceleration. Dynamic equilibrium occurs when the net force and net moment on a system are zero, allowing the system to move with constant velocity.2. Describe the function of a flywheel in a mechanical system. 答案：A flywheel is a rotating mechanical device that stores rotational kinetic energy. It smooths out fluctuations in the power delivery of an engine or motor, providing a moreconstant output.3. What is the purpose of a heat exchanger in a mechanical system?答案：A heat exchanger is a device used to transfer heat between two or more fluids without mixing them. Its purposeis to either cool a hot fluid or heat a cold fluid, improving the efficiency of the system.4. Explain the concept of a control system in mechanical engineering.答案：A control system in mechanical engineering is a system that regulates the behavior of other systems or processes. It uses feedback to compare the actual output with the desired output and makes adjustments to minimize the difference, ensuring the system operates as intended.。

化学化工英语试题及答案一、选择题（每题2分，共20分）1. Which of the following is a chemical element?A. WaterB. OxygenC. HydrogenD. Carbon答案：B, C, D2. The chemical formula for table salt is:A. NaOHB. NaClC. HClD. NaHCO3答案：B3. What is the process called when a substance changes from a solid to a liquid?A. SublimationB. VaporizationC. MeltingD. Condensation答案：C4. In the periodic table, which group contains alkali metals?A. Group 1B. Group 2C. Group 17D. Group 18答案：A5. What is the name of the process where a substance decomposes into two or more substances due to heat?A. CombustionB. OxidationC. ReductionD. Decomposition答案：D6. Which of the following is a physical property of a substance?A. ColorB. TasteC. SolubilityD. Reactivity答案：A7. What is the term for a compound that releases hydrogen ions (H+) when dissolved in water?A. BaseB. AcidC. SaltD. Neutral答案：B8. The law of conservation of mass states that in a chemical reaction:A. Mass is lostB. Mass is gainedC. Mass remains constantD. Mass can be converted into energy答案：C9. Which of the following is a type of chemical bond?A. Ionic bondB. Covalent bondC. Hydrogen bondD. All of the above答案：D10. What is the name of the process where a substance absorbs energy and changes from a liquid to a gas?A. MeltingB. VaporizationC. SublimationD. Condensation答案：B二、填空题（每题2分，共20分）1. The symbol for the element iron is ________.答案：Fe2. The pH scale ranges from ________ to ________.答案：0 to 143. A compound that produces a basic solution when dissolvedin water is called a ________.答案：base4. The smallest particle of an element that retains its chemical properties is called a ________.答案：atom5. The process of separating a mixture into its individual components is known as ________.答案：separation6. The study of the composition, structure, and properties of matter is called ________.答案：chemistry7. The process of a substance changing from a gas to a liquid is called ________.答案：condensation8. A(n) ________ reaction is a type of chemical reactionwhere two or more substances combine to form a single product. 答案：synthesis9. The volume of a gas at constant temperature and pressureis directly proportional to the number of ________.答案：moles10. The process of converting a solid directly into a gas without passing through the liquid phase is known as ________. 答案：sublimation三、简答题（每题10分，共30分）1. Explain what is meant by the term "stoichiometry" in chemistry.答案：Stoichiometry is the calculation of the relative quantities of reactants and products in a chemical reaction.It is based on the law of conservation of mass and involvesthe use of balanced chemical equations and the molar massesof substances to determine the amounts of reactants needed to produce a certain amount of product or the amounts ofproducts formed from a given amount of reactant.2. Describe the difference between a physical change and a chemical change.答案：A physical change is a change in the state or form of a substance without altering its chemical composition. Examples include melting, freezing, and boiling. A chemical change, on the other hand, involves a change in the chemical composition of a substance, resulting in the formation of new substances. Examples include combustion and rusting.3. What are the three main types of chemical bonds, and givean example of each.答案：The three main types of chemical bonds are ionic bonds, covalent bonds, and metallic bonds. An ionic bond is formed when electrons are transferred from one atom to another, resulting in the formation of oppositely charged ions. An example is the bond between sodium (Na) and chloride (Cl) in table salt (NaCl). A covalent bond is formed when two atoms share electrons, as seen in water (H2O) where hydrogen atoms share electrons with oxygen. Metallic bonds occur in metals, where a "sea" of delocalized electrons is shared among positively charged metal ions, as in sodium metal。

fundamentals of thermoelectricityoxford 2015The fundamentals of thermoelectricity, as discussed in the Oxford 2015 book, are crucial for understanding the conversion of heat into electrical energy. This field combines principles from thermodynamics, solid-state physics, and materials science to explore the behavior and performance of thermoelectric devices. Thermoelectricity has gained significance in recent years due to its potential application in waste heat recovery, portable power generation, and energy-efficient cooling systems. Let's dive into some key concepts covered in this book.Thermoelectric phenomena arise from a temperature gradient across a material or device. The underlying principle is the Seebeck effect, which describes the generation of an electric voltage when there is a temperature difference between two points in a conductor or semiconductor. This voltage is proportional to the gradient in temperature and depends on the material properties.热电现象是在材料或器件中存在温度梯度时产生的。

树冠降温效应的风洞试验及关联模型徐伟;付海明【摘要】The influence of structural characteristics of single plant canopy were analyzed in different wind speed and ambient temperature by wind tunnel experiment.According to the characteristics of canopy structure,the related structural parameters of the leaf area index and the filling ratio were proposed.Through regression analysis of the influence of canopy structure parameters on the thermal environment,the equations of the relation between the coefficient of canopy temperature drop and wind speed and leaf area index were put forward.To verify the adaptability of the correlation,a variety of tree species were tested.The results show that the canopy has significant cooling effect on the surrounding thermal environment,and the canopy temperature drop coefficient shows a certain regularity with the structural parameters,wind speed and ambient temperature.The cooling effect is different for the different size of the canopy leaves.The proposed canopy temperature drop correlation has certain applicability,but it is necessary to make some corrections to predict the cooling effect of different canopies.%通过风洞试验,分析了不同风速和环境温度下单一品种树冠结构特性对环境温度的影响.针对树冠结构特性提出相关结构参数(叶面积指数、填充率),讨论了其对周围热环境的影响规律,提出了树冠温度下降系数与风速、叶面积指数的关联表达式,并采用多种树冠的测试数据对该关联式的适应性进行对比验证.结果表明:树冠对周围空气热环境有显著的降温效果,树冠温度下降系数与其结构参数、风速和环境温度呈一定规律;叶片尺寸不同的树冠,其降温效果也不同;提出的树冠温降关联式具有一定的适用性,但预测不同树冠的降温效仍需进行必要的修正.【期刊名称】《东华大学学报（自然科学版）》【年(卷),期】2017(043)006【总页数】6页(P908-913)【关键词】风洞试验;树冠;环境温度;热环境【作者】徐伟;付海明【作者单位】东华大学环境科学与工程学院,上海201620;东华大学国家环境保护纺织工业污染防治工程技术中心,上海201620;东华大学环境科学与工程学院,上海201620;东华大学国家环境保护纺织工业污染防治工程技术中心,上海201620【正文语种】中文【中图分类】TU831.3提高城市绿化率已经成为缓解城市热岛效应、节约能源和提高人体热舒适条件的重要策略[1].植被冠层小气候环境是冷却和调节空气环境的主要因素，日间树冠周围温度相比其他地方普遍低2 ℃，在有些时间甚至可以达到6 ℃[2].研究发现，绿化形式和面积是影响环境温度的主要因素，不同类型植被之间存在差异，并且树的阴影可以有效降低空气温度.然而，在没有阴影的绿化地区或低矮植被地区，空气环境温度也会发生改变，这表明可能是植被蒸发冷却发挥了作用[3-4].文献[5]对炎热的干旱地区的6种景观策略进行了研究，使用树冠和草坪的不同组合与一个架空的遮阳网进行对比，结果发现，采用绿化措施的空气温度要明显低于遮阳网的情况，且遮荫树和草坪组合的情况产生的温度下降高达2.5 ℃.文献[6]研究表明，绿化可以大大改善城市小气候，减轻热岛效应，降低夏季空气温度，随着绿化面积和绿化率的增加，植被使周围环境温度的下降高达4 ℃.这种效果不仅作用于绿化地区本身，更可以影响背风面几千米的地区.因此，增加城市环境中的植被是减轻热岛效应的一种有效方式，并有利于城市中心大气环境温度的降低.文献[7]用现场监测数据和气象模拟的方法对热岛现象的成因和影响进行了讨论，结果表明，地表反照率和植被覆盖率可以有效改变近地表气候.绿化面积的增加可使空气温度降低约2 ℃，在某些情况下，局部空气温度下降可以达到4 ℃.植被影响环境温度，不仅因为其可以阻挡日光直射和产生阴影，且植被叶片的蒸腾作用也是决定因素[8].文献[9]研究了植被和城市农业的蒸腾量对缓解城市温度的影响，结果表明，城市环境中的树冠可以导致周围环境温度降低0.5～4.0 ℃.文献[10]利用地面激光扫描(TLS)的三维树木冠层和遮阴数据分析植被的冷却效果，发现树的冷却效果随树冠大小和密度、叶的光学性能的不同而变化，树冠体积和叶面积指数导致的降温峰值可达到3 ℃，对4种林地(香樟、水杉、广玉兰、阔混交林)进行对比分析可知，水杉林地降温效果最大，其余由大到小依次是香樟、广玉兰、阔混交林林地.此研究结果可用于指导及帮助城市绿地规划选择最好的树种.综上所述，植被绿化具有降低环境温度、增加环境湿度的作用，是缓解城市热岛效应的有效手段，然而关于树冠结构特性对环境温度影响的定量研究较少，不利于通过城市绿化及规划设计的方法缓解城市热岛效应.因此，本文通过风洞试验对绿色植被的叶面积指数、环境的流动风速及温度与树冠的降温效应进行测试，旨在于探讨单一品种树冠的降温效应与其主要影响因素的关联关系，为城市的绿化及规划设计提供理论依据，以便提高城市绿化率及缓解城市热岛效应.1 风洞试验1.1 植被对环境温度的影响植被对环境温度的影响主要包含3个方面：(1)遮阳降低太阳辐射得热；(2)植物的蒸腾作用将太阳辐射转化为潜热来调节日光导致的热增益；(3)叶片表面与空气的对流换热[6].本文主要研究树冠对来流空气的温度影响，因此遮阳效果对试验影响较小，主要考虑后两方面的影响.本文将树木当做多孔介质进行处理，并作如下简化：将冠层部分(树叶+树枝)考虑为整体，即将树枝近似为树叶；忽略树干的影响.本文的试验样本选取新鲜的树枝叶，将其扎成与现实树木冠层相似的形状，且与现实树冠具备相同的热物性，保持置于风洞中的样本与位于行道的树木的物理现象相似.由于上海地区夏季平均风速为3.1 m/s，试验设备的风速范围设定为1～3 m/s.采用风洞试验装置与实际物理现象、几何尺寸及雷诺准则相似.1.2 风洞试验参数风洞试验装置如图1所示.A、 B、 C为测试点，A-B为对比段，其间均匀分布着3个风速测孔(如图1中圆圈所示)，B-C为试验段，其长度为0.7 m， D-E为填充区域，其长度为0.5 m，矩形风管横截面尺寸为0.255 m×0.265 m.1—变频器； 2—风机； 3—加热器； 4—整流栅； 5—干湿球温度计； 6—栅栏；7—表盘； 8—调压旋钮图1 风洞试验装置Fig.1 Experimental apparatus of wind tunnel通过改变置于填充区域内的试验树枝的数量以及叶片数，获得不同的叶面积指数和填充率.试验时，通过加热器和调压旋钮输入定常热量获得3种不同的空气温度(25、30和35 ℃)，调节无级变频装置(0～50 Hz内无级调节)向测试段输送速度为1～3 m/s的连续风.通过热线风速仪在风速测孔处测量风速，利用A、 B、 C 3个测点的干湿球温度计测量温度，并通过表盘连接计算机记录A、 B、 C测点的空气干球温度.2 试验方案设计2.1 试验内容本试验所采用的树叶均为上海地区校园常见常青树种，在3种环境温度(25、 30和35 ℃)条件下，分别测试了5种不同风速(1～3 m/s)下5种叶面积指数树冠的降温效果.试验树叶选择叶片大小适当的大叶香樟树叶，并采用其他树种叶片(小叶香樟、白杨树、灌木)进行了重复试验，以验证不同树种之间是否具有相同的规律.根据叶片尺寸的不同，引入等效直径de，即与叶片具有相同面积的圆的直径.将de≤5 cm的树叶视为小叶片，如小叶香樟；5 cm<de≤ 10 cm的树叶视为中等叶片，如大叶香樟和灌木；de>10 cm的树叶视为大叶片，如白杨树.2.2 数据处理依据上述方法采用变频风机改变风速，采用干湿球温度计测量气流经过树枝前后的温度降，获得树枝前后温差与叶面积指数、填充率及风速变化关系曲线.本文定义温度降Δt=tB-tC，为树冠前段空气温度(tB)和树冠后段空气温度(tC)之间的气温差，计算所有的实测温度降并取其平均值.其中A-B段为无填充对比段，通过对比可明显观察到树冠对空气温度的影响程度以及试验误差.3 结果与讨论本文旨在探究温度下降系数(Ct)与环境温度(t)、树冠结构参数(叶面积指数(LLAI)和填充率(Vp))、风速(v)之间的关系.目前，国内外关于树冠结构参数对空气温度影响的定量研究成果比较少，本文依据风洞试验结果对其进行简单的量化分析，采用文献[11]提出的树冠温度下降模型，如式(1)所示.Δt=Ct·t(1)本文在式(1)的基础上考虑树冠本身蒸腾作用对周围环境温度的影响，而蒸腾作用与环境温度相关[6]，故假设温度下降系数是关于环境温度、树冠结构参数及风速的函数，改变树冠结构参数及风速进行试验，研究温度下降系数与树冠结构参数及风速的关联.3.1 叶面积指数和填充率之间的关系通常可采用叶面积指数和填充率来描述单一品种树冠的结构参数.叶面积指数又叫叶面积系数，是指单位土地面积上植物叶片总面积占土地面积的倍数，其是反映植物群体生长状况的一个重要指标.本文采用树叶图像扫描技术，测试树叶的总表面积，采用总表面积与其沿气流流动方向的投影面积之比，可获得单一品种树冠的叶面积指数.如果将树冠视为多孔介质，那么可采用填充率来描述树冠结构.填充率为树叶的实际体积与其所占有的表观总体积之比.试验采用浸水法进行填充率测试，即将树叶及树枝浸入固定容积的容器内，计算其排除的体积与容器体积之比，即可获得某品种树冠的填充率.4种不同品种的树冠填充率与其叶面积指数关系测试结果如图2所示.图2 4种不同品种的树冠填充率与叶面积指数的关系Fig.2 Relationship between filling rate and leaf area index of four kinds of tree species由图2可知，填充率与叶面积指数成线性正比关系，其线性相关系数与树冠种类相关，二者为非独立自变量，故可采用填充率或叶面积指数来描述树冠结构.本文采用叶面积指数研究其与树冠温度下降系数的相关关系.3.2 树冠下降温度与其影响因素分析由相关研究文献及试验结果可知，树冠温度下降的主要影响因素为叶面积指数、风速及环境温度.本文采用大叶香樟树叶在3种不同环境温度下进行风洞试验，得到树冠温度下降量与风速及叶面积指数的关系图如图3所示.(a) 25 ℃(b) 30 ℃(c) 35 ℃图3 不同环境温度下树冠温度下降量与风速及叶面积指数的关系Fig.3 The relationship between canopy temperature drop and wind speed and leaf area index under different ambient temperatures由图3可知：当环境温度较低为25 ℃时，温降较小且误差较大，无法观察到明显的变化规律，但还是可以看出温降随叶面积指数的增加而增大；当环境温度上升至30 ℃时，已经可以观察到明显的变化规律，温降随叶面积指数的增加而增大，随风速增大而减小，误差也相对减小；当环境温度为35 ℃，这种变化趋势已经非常明显了，试验误差随环境温度增加而减小，在这时已在可以接受的范围内.纵观图3可以看出，温度下降系数与环境温度和叶面积指数成正比，与风速成反比.下面将讨论Ct与这3个参数的具体关系.由于环境温度为25 ℃时的温降较小且误差较大，这里主要以环境温度为30和35 ℃作为主要讨论依据.由图3可以发现，温度下降系数与环境温度、叶面积指数和风速相关，即Ct=f(it， LLAI， iv)，其中，it为环境温度除以基准温度(取35 ℃)，iv为试验风速除以基准风速(取1 m/s)，实现温度和速度的无量纲化.风洞试验所得温度变化(经过无量纲处理)与风速之间的关系如图4所示.试验所得温度变化(经过无量纲处理)与叶面积指数之间的关系如图5所示.(a) 30 ℃(b) 35 ℃图4 不同叶面积指数下树冠温度下降与风速的拟合关系Fig.4 Fitting relationship between canopy temperature drop and wind speed under different leaf area indexes(a) 30 ℃(b) 35 ℃图5 不同风速下树冠温度下降与叶面积指数的拟合关系Fig.5 Fitting relationship between canopy temperature drop and leaf area index under different wind speed根据风洞试验所得树冠温度下降系数与叶面积指数和风速之间关系，本文提出如下表达式：式中：a、 b、 c、 d、 e均为拟合系数.在以下分析中利用此表达式进行拟合.根据风洞试验所得温度变化与叶面积指数和风速之间的关系，将所有的试验结果拟合得出：Ct =(-3.35×10-2+5.22×10-3×LLAI+R2=0.795(2)所以Δt=(-3.35×10-2+5.22×10-3×LLAI+(3)为了验证式(3)是否适用于其他树种，本文选取其他3种树种进行了重复试验，包括叶片尺寸较小的小叶香樟、叶片尺寸偏大的白杨树以及叶片尺寸与本试验叶片大小相当的灌木树叶.当环境温度为35 ℃、风速为2.5 m/s时，不同树冠的温度下降系数与叶面积指数的关系如图6所示.当环境温度为35 ℃、叶面积指数为8.2时，不同树冠温度下降系数与风速的关系如图7所示.图6 不同树冠的温度下降系数与叶面积指数的关系(风速为2.5 m/s时)Fig.6 The relationship between canopy temperature drop coefficient and leaf area index of different tree species(when wind speed is 2.5 m/s)图7 不同树冠的温度下降系数与风速的关系(叶面积指数为8.2时)Fig.7 The relationship between canopy temperature drop coefficient and wind speed of different tree species(when leaf area index is 8.2)由图6可知，不同树种之间的温度下降系数并不相同，本文提出的树冠温降关联式预测值与不同树冠的试验测试值存在一定偏差.其中：叶片尺寸与本试验相当的灌木树叶的Ct偏差较小，约为15%；叶片尺寸较小的小叶香樟相差最大，特别是叶面积指数极小的情况；叶片尺寸较大的白杨树的Ct与本试验结果偏差较大，约为60%，而且Ct预测与试验偏差随叶面积指数的上升而增大.由图7可以发现，在叶面积指数较小为8.2时，灌木树叶的Ct与本试验拟合结果偏差最小，约为5%，小叶香樟和白杨树叶的Ct均与本试验拟合结果有较大偏差，约为50%，且这两种叶片的偏差程度是相当的.因此，本文试验结果可以适用于叶面积指数适当的相似尺寸树叶，其他小叶片或者大叶片的树种可能需要进行相关修正.产生偏差的原因除了叶片尺寸之外，还包括人为误差、试验风管的局限性、每次试验需采集新鲜叶片.由图7可知，不同树冠的温度下降系数与风速的关系变化趋势是基本一致的.本文提出的树冠温度下降系数关联表达式在相近树种间具有一定的适用性，对其进行必要的修正可预测不同树冠的降温效应.因国内外直接研究树冠结构参数对周围环境温度(主要是来流空气)影响的文献较少，因此无法做直接对比.本文在风洞中进行试验，叶片所类比的树冠和风洞组成了一个微环境，在叶面积指数为11.81的情况下最大温降为1.15 ℃.4 结语本文采用风洞试验的方法，在3种环境温度、5种风速条件下，研究了5种叶面积指数的大叶香樟树冠对周围环境温度的影响规律.依据试验结果，拟合得出树冠温度下降系数与叶面积指数和风速之间的关联表达式.同时，对其他树种进行重复试验，并将试验结果与本文拟合结果进行对比，发现只有叶片尺寸与大叶香樟相似的灌木树叶的树冠温度下降系数拟合结果与试验结果具有高度的相似性，叶片尺寸较小和较大的树种均存在较大偏差.因此，本文拟合的树冠温度下降系数关联表达式可适用于叶片尺寸与大叶香樟相似的树种，如用于其他叶片尺寸的树种，拟合表达式需加入其他参数或进行修正，此内容有待进一步研究.本文试验结果存在一定的不确定性，多次重复试验后发现每次测试结果存在一定偏差，可能是测量仪器本身的精度局限性对结果造成的偏差.另外，本文试验仅在实验室进行，未在其他地区进行验证，具有一定的地域局限；采取风洞试验的形式，树叶的堆积形态与实际树冠存在一定差异；风洞试验风管的局限性可能导致叶面积指数较大时与实际环境下的树冠结构参数存在较大差异.上述这些因素对本文树冠温降关联式的预测结果有一定影响，有待进一步完善.参考文献[1] KURN D M， BRETZ S E， HUANG B， et al. 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Vegetation in the urban environment： Microclimatic analysis and benefits[J]. Energy & Buildings，2003， 35(1)：69-76.[7] TAHA H. Urban climates and heat islands： Albedo，evapotranspiration， and anthropogenic heat[J]. Energy & Buildings，1997， 25(2)：99-103.[8] BOUKHABL M， ALKAM D. Impact of vegetation on thermal conditions outside， thermal modeling of urban microclimate， case study： The street of the republic， Biskra[J]. Energy Procedia， 2012， 18：73-84. [9] QIU G Y， HONG -Yong L I， ZHANG Q T， et al. Effects of evapotranspiration on mitigation of urban temperature by vegetation and urban agriculture[J]. Journal of Integrative Agriculture， 2013， 12(8)：1307-1315.[10] KONG F， YAN W， ZHENG G， et al. Retrieval of three-dimensional tree canopy and shade using terrestrial laser scanning(TLS) data to analyze the cooling effect of vegetation[J]. Agricultural and Forest Meteorology，2016， 217： 22-34.[11] 汪悦越，付海明，胡文娟，等.树冠周围温度分布特性数值模拟与试验[J].东华大学学报(自然科学版)，2016，42(2)：258-262.。

case studies in thermal engineering参考文献缩写以下是几个关于热工程的案例研究的参考文献缩写例子：1. DBS: Gharehkhani, Samira, and Matteo Bortolini. "Exergy analysis of a proton exchange membrane fuel cell system." Energy 36.4 (2011): 2119-2129.2. JES: Wang, Tao, and Ruzhu Wang. "Performance characteristics of an adsorption refrigeration system using activated carbon-R134a pair." Applied Thermal Engineering 27.5-6 (2007): 992-998.3. JFE: Tavanaie, Mohammad Ali, Mohammad Haji-Sheikh, and Ali A. Rownaghi. "Experimental investigation of the effects of internal ribs on heat transfer and pressure drop in a rectangular channel." Journal of Fluids Engineering 130.7 (2008): 071702.4. AEE: Yu, Zhibin, et al. "Effect of saline water on the performance of a solar thermoelectric generator with heat pipes." Applied Energy 290 (2021): 116586.5. IJV: Waltman, Sarah W., and Jacqueline F. Roen. "Thermal performance study of single-loop and dual-loop liquid flat plate solar collectors." International Journal of Energy Research 35.10 (2011): 847-859.请注意，这里提供的仅仅是一些例子，具体要根据您所参考的具体文献来确定正确的缩写。

大角度晶界的英语Abstract:Macroscopic grain boundaries (MGBs) are a critical feature in polycrystalline materials, significantly influencing mechanical properties, thermal conductivity, and electrical conductivity. This paper delves into the characteristics, formation mechanisms, and the impact of MGBs on the performance of materials, with a focus on their rolein various applications.1. IntroductionGrain boundaries are interfaces between two crystalline grains in a polycrystalline solid. When the misorientation between grains is significant, these boundaries can be considered macroscopic, exhibiting distinct properties that differ from those of the bulk material. The study of MGBs is essential for understanding material behavior and optimizing performance in engineering applications.2. Characteristics of Macroscopic Grain BoundariesMacroscopic grain boundaries are characterized by their misorientation angles, which are typically greater than 15 degrees. They can be classified into several types based on the crystallographic relationship between the grains they separate:- Twin boundaries: Where the misorientation is a mirror reflection across the boundary plane.- Coincidence site lattice (CSL) boundaries: Where a high density of lattice points from both grains coincide at the boundary.- General boundaries: With no specific crystallographic relationship, these are the most common type.3. Formation MechanismsMGBs can form during various material processing techniques:- Recrystallization: After severe deformation, grains can grow, leading to the formation of MGBs.- Grain growth: During annealing, larger grains can consume smaller ones, resulting in increased misorientations at the boundaries.- Phase transformations: Changes in crystal structure during phase transitions can create MGBs.4. Impact on Material PropertiesThe presence of MGBs has a profound effect on the properties of polycrystalline materials:- Strength: MGBs can impede dislocation motion, increasing the material's strength.- Ductility: They can act as sites for crack initiation, affecting ductility.- Conductivity: MGBs can scatter electrons and phonons, reducing thermal and electrical conductivity.5. ApplicationsUnderstanding MGBs is crucial for optimizing materials in various applications:- Metalworking: Controlling grain size and boundary characteristics can enhance the mechanical properties of metals.- Electronics: In semiconductor devices, MGBs can influence carrier mobility and device performance.- Ceramics: MGBs in ceramics can affect fracture toughness and thermal shock resistance.6. Experimental Techniques for Studying MGBsSeveral experimental methods are used to study MGBs:- Scanning electron microscopy (SEM): Can reveal the morphology of MGBs.- Transmission electron microscopy (TEM): Provides detailed information on the atomic structure of boundaries.- Electron backscatter diffraction (EBSD): Allows for the determination of grain orientation and the identification of MGBs.7. Computational ModelingComputational techniques, such as molecular dynamics and phase-field modeling, are used to simulate MGB formation and behavior:- Molecular Dynamics (MD): Offers insights into atomic-scale processes at MGBs.- Phase-Field Modeling: Can predict the evolution of grain structures and boundary characteristics during processing.8. ConclusionMacroscopic grain boundaries play a critical role in determining the properties of polycrystalline materials. Understanding their characteristics, formation, and impact is essential for the development of advanced materials with tailored properties for specific applications. Future research should focus on developing new techniques to control MGBs and on multiscale modeling to predict their effects on material behavior.References1. Hull, D., & Bacon, D. J. (2011). Introduction to Dislocations (5th ed.). Butterworth-Heinemann.2. Humphreys, F. J., & Hatherly, M. (2004). Recrystallization and Related Annealing Phenomena (2nd ed.). Elsevier.3. Gottstein, G. (2002). Physical Foundations ofMaterials Science. Springer.4. Randle, V. (2017). Grain Boundary CharacterDistribution and its Applications. CRC Press.This document provides a comprehensive overview of macroscopic grain boundaries, discussing theircharacteristics, formation, and impact on material properties, as well as the experimental and computational techniques used to study them. It concludes with the significance of MGBs in material applications and the importance of future researchin this area.。

The Thermodynamics of the Earths Atmosphere The Earth's atmosphere is a complex system that interacts with the planet's surface, oceans, and biosphere. The study of the thermodynamics of the atmosphere is essential in understanding the behavior of this system and how it affects our planet. Thermodynamics is the study of the relationships between heat, energy, and work. In the context of the Earth's atmosphere, thermodynamics helps us understand the processes that govern the movement of air, the formation of weather patterns, and the distribution of energy throughout the system.One of the key principles of thermodynamics is the conservation of energy. This principle states that energy cannot be created or destroyed; it can only be transferred or converted from one form to another. In the Earth's atmosphere, energy is transferred through a variety of processes, including radiation, conduction, and convection. Radiation is the transfer of energy through electromagnetic waves, such as those from the sun. Conduction is the transfer of energy through direct contact, such as when the ground heats the air above it. Convection is the transfer of energy through the movement of fluids, such as when warm air rises and cool air sinks.Another important principle of thermodynamics is the second law of thermodynamics, which states that the total entropy of a closed system always increases over time. Entropy is a measure of the disorder or randomness of a system. In the Earth's atmosphere, entropy increases as energy is transferred from one place to another. This means that the atmosphere tends towards a state of maximum disorder, which can lead to the formation of weather patterns and other complex phenomena.The thermodynamics of the Earth's atmosphere also plays a crucial role in the global climate system. The atmosphere acts as a greenhouse, trapping heat from the sun and regulating the temperature of the planet. This is known as the greenhouse effect, and it is essential for life on Earth. However, human activities such as the burning of fossil fuels have increased the concentration of greenhouse gases in the atmosphere, leading to an enhanced greenhouse effect and global warming. Understanding the thermodynamics ofthe atmosphere is therefore crucial in addressing the challenges of climate change and developing strategies to mitigate its impacts.From a human perspective, the thermodynamics of the Earth's atmosphere has a profound impact on our daily lives. Weather patterns such as hurricanes, tornadoes, and thunderstorms are all driven by the movement of air and the transfer of energy through the atmosphere. These phenomena can have devastating effects on communities, causing loss of life and property damage. Understanding the thermodynamics of the atmosphere can help us predict and prepare for these events, improving our ability to respond and recover from natural disasters.In conclusion, the study of the thermodynamics of the Earth's atmosphere is essential in understanding the behavior of this complex system and its impact on our planet. Through the principles of conservation of energy and the second law of thermodynamics, we can gain insights into the processes that govern the movement of air, the formation of weather patterns, and the distribution of energy throughout the system. From a human perspective, this knowledge is critical in predicting and preparing for natural disasters and addressing the challenges of climate change. As we continue to explore the mysteries of our planet's atmosphere, the principles of thermodynamics will undoubtedly play a central role in our understanding of this fascinating and complex system.。

GeneralThe following questionnaires are used to select sensors according to the client's requirements.The characteristics shown in the catalogue are given with respect to a defined environment (worst case conditions).The technical requirements will not always reach these extreme limits, and it is possible, following confirmation by us, to propose higher maximum electrical or thermal values to those published, thanks to a knowledge and detailed analysis of the sensor operating environment.A technical relationship between the client and ABB will allow the proposal of the best selection of sensors, equally from the viewpoint of performance and economy.Two principal areas are considered in the selection of a sensor:–the electrical aspect–the thermal aspectThe sensor performance is based on a combination of electrical and thermal conditions; any values other than those indicated in this catalogue cannot be guaranteed unless validated by us. The information below is only valid for sensors using closed loop Hall effect technology.Contact your local supplier for other technologies.Profile missionDue to the design of converters with integrate more power with less volume, sensors are very constraint; leading to reduce their life time. As a matter of fact, even though the application main conditions are well within the sensors characteristics, these conditions have an impact on the sensor life time.The main general characteristics that involves the sensors life time are the following:–the ambient temperature above 40 °C. It is usually said that every additional 10 °C, the life time is reduced by a factor of 2. Of course, this value is a theoretical value and has to be defined in line with the concerned project.–the ambient temperature variations also impact the sensor life time. Even small variations (like 10 °C) can change the life time of the sensor especially on the electronic part.–the way the sensors are used also impact its duration (numbers of ON/OFF per day, average current or voltage value, powersupply value, load resistor value, vibrations levels…)The above general impacting conditions are well defined in standards like IEC 62380, UTE C 80-810 and must be consider during any new converter design.ABB can provide theoretical reliability calculation based on specific profile mission of your projects.Electrical characteristicsThe electrical characteristics values mentioned in this catalogue are given for a particular sensor operating point. These values may vary, according to the specific technical requirement, in the following way:–The primary thermal current (voltage) (I PN or U PN) may be increased if:-t he maximum operating temperature is lower than thevalue shown in the technical data sheet-the sensor supply voltage (V A) is reduced-the load resistance value (R M) is increased–The maximum current (voltage) measurable by the sensor may be increased if:-the maximum operating temperature is lower than thevalue shown in the technical data sheet-the sensor supply voltage (V A) is increased-the secondary winding resistance value (R S) is reduced(e.g. by using a lower transformation ratio)-the load resistance value (R M) is reducedThermal characteristicsThe operating temperature values mentioned in this catalogue are given for a particular sensor operating point. These values may vary, according to the specific technical requirement, in the following way:–The maximum operating temperature may be increased if: -the primary thermal current (voltage) (I PN or U PN) is reduced -the sensor supply voltage (V A) is reduced-the load resistance value (R M) is increasedPS: The minimum operating temperature cannot be lower than that shown in the technical data sheet as this is fixed by the lower temperature limit of the components used in the sensor.74S21Application1. Application :–Variable speed drive ................................................................ –UPS ....................................................................................... –Wind generator ....................................................................... –Active harmonic filter ............................................................... –Welding machines ................................................................... –Solar ...................................................................................... –Other (description) ......................................................................2. Quantity per year: ...........................................................................Mechanical characteristics1. Sensor fixing:–By soldering to the PCB .......................................................... –By the enclosure ..................................................................... –By the primary conductor ........................................................ 2. Primary conductor:–Cable diameter ................................................................... (mm) –Cable connection size ......................................................... (mm) –Bar size .............................................................................. (mm)3. Secondary connection:–By connector .......................................................................... –By cable without connector ..................................................... –Other ......................................................................................Sensor environmental conditions1. Minimum operating temperature ................................................ (°C)2. Maximum operating temperature ............................................... (°C)3. Presence of strong electromagnetic fields ....................................4. Max. continuous primary conductor voltage ................................ (V)5. Main reference standards ................................................................Electrical characteristics1. Nominal current (I PN ) ......................................................... (A r.m.s.)2. Current type (if possible, show current profile on graph):–Direct ..................................................................................... –Alternating .............................................................................. 3. Bandwidth to be measured ...................................................... (Hz)4. Current measuring range:–Minimum current .................................................................... (A) –Maximum current ................................................................... (A) –Duration (of max. current) .................................................... (sec) –Repetition (of max. current) ......................................................... –Measuring voltage (on R M ) at max current .............................. (V)5. Overload current (not measurable):–Not measurable overload current ........................................... (A) –Duration.............................................................................. (sec) –Repetition ...................................................................................6. Sensor supply voltage:–Bipolar supply voltage .......................................................... (±V) –Unipolar supply voltage .......................................... (0 +V or 0 -V)7. Output current–Secondary current at nominal current I PN ............................. (mA) 8. Current output (NCS range only)–Secondary current at maximum current I PMAX ....................... (mA)9. Voltage output–Secondary voltage at nominal current I PN ............................... (V)10. Voltage output (NCS range only)–Secondary voltage at maximum current I PMAX (V)Company:Address:Tel:Name:Fax:Email:Other requirements (description)74S 0201Company:Address:Tel:Name:Fax:Email:Other requirements (description)Application1. Project name ...................................................................................2. Application:Rolling stock:–Power converter ..................................................................... –Auxiliary converter ................................................................... –Other ......................................................................................Short or long distance train:–Power converter ..................................................................... –Auxiliary converter ...................................................................Metro or tramway:–Power converter ..................................................................... –Auxiliary converter ................................................................... Fixed installation (e.g. substation)..................................................... 3. Quantity per year: ............................................................................4. Total quantity for the project.............................................................Mechanical characteristics1. Sensor fixing:–By the enclosure ..................................................................... –By the primary conductor ........................................................ 2. Primary conductor:–Cable diameter ................................................................... (mm) –Bar size .............................................................................. (mm) 3. Secondary connection:–Screw or Faston...................................................................... –By connector .......................................................................... –By shielded cable .................................................................... –Other ...................................................................................... Electrical characteristics1. Nominal current (I PN ) .......................................................... (A r.m.s.)2. C urrent type (if possible, show current profile on graph):–Direct ..................................................................................... –Alternating .............................................................................. 3. Bandwidth to be measured ....................................................... (Hz)4. Current measuring range:–Minimum current .................................................................... (A) –Maximum current ................................................................... (A) –Duration (of max. current) .................................................... (sec) –Repetition (of max. current) ......................................................... –Measuring voltage (on R M ) at max current .............................. (V)5. Overload current (not measurable):–Not measurable overload current ............................................(A) –Duration.............................................................................. (sec) –Repetition ...................................................................................6. Sensor supply voltage:–Bipolar supply voltage .......................................................... (±V) –Unipolar supply voltage .......................................... (0 +V or 0 -V)7. Output current–Secondary current at nominal current I PN ............................. (mA) 8. Current output (NCS125 & NCS165 only for fixed installations)–Secondary current at maximum current I PMAX ....................... (mA)9. Voltage output (NCS125 & NCS165 only for fixed installations)–Secondary voltage at nominal current I PN ............................... (V)10. Voltage output (NCS125 & NCS165 only for fixed installations)–Secondary voltage at maximum current I PMAX (V)Sensor environmental conditions1. Minimum operating temperature ................................................ (°C)2. Maximum operating temperature ............................................... (°C)3. Average nominal operating temperature ......................................(°C)4. Maximum continuous primary conductor voltage ..........................(V)5. Main reference standards ................................................................74S 0201Company:Address:Tel:Name:Fax:Email:Other requirements (description)Application1. Project name ...................................................................................2. Application:Short or long distance train:–Power converter ..................................................................... –Auxiliary converter ...................................................................Metro or tramway:–Power converter ..................................................................... –Auxiliary converter ...................................................................Fixed installation (e.g. substation) ................................................ 3. Quantity per year: ............................................................................4. Total quantity for the project.............................................................Mechanical characteristics1. Primary connection:–By screw ................................................................................ –Other ...................................................................................... 2. Secondary connection:–Screw or Faston...................................................................... –By connector .......................................................................... –Other ...................................................................................... Electrical characteristics1. Nominal voltage (U PN ) ........................................................ (V r.m.s.)2. Voltage type (if possible, show voltage profile on graph):–Direct ..................................................................................... –Alternating .............................................................................. 3. Bandwidth to be measured ...................................................... (Hz)4. Voltage measuring range:–Minimum voltage .................................................................... (V) –Maximum voltage ................................................................... (V) –Duration (at max. voltage) .................................................... (sec) –Repetition (at max. voltage) ......................................................... –Measuring voltage (on R M ) at max voltage ............................... (V)5. Overload voltage (not measurable):–Not measurable overload voltage ............................................ (V) –Duration.............................................................................. (sec) –Repetition ................................................................................... –Category (from OV1 to OV3) ........................................................6. Sensor supply voltage:–Bipolar supply voltage .......................................................... (±V) –Unipolar supply voltage .......................................... (0 +V or 0 -V)7. Output current–Secondary current at nominal voltage U PN ............................ (mA)Sensor environmental conditions1. Minimum operating temperature ................................................ (°C)2. Maximum operating temperature ............................................... (°C)3. Average nominal operating temperature .....................................(°C)4. Main reference standards ................................................................74S 0201Company:Address:Tel:Name:Fax:Email:Other requirements (description)Application1. Project name ...................................................................................2. Application:Short or long distance train:–Power converter ..................................................................... –Auxiliary converter ...................................................................Metro or tramway:–Power converter ..................................................................... –Auxiliary converter ...................................................................Fixed equipment (e.g. substation) ................................................ 3. Quantity per year: ...........................................................................4. Total quantity for the project.............................................................Electrical characteristics1. Nominal voltage (U PN ) ............................................................ (V DC)2. Maximum voltage long duration: 5 min (U MAX2) ........................ (V DC)3. Maximum voltage overload: 20 ms (U MAX3) .............................. (V DC)4. Minimum voltage to be detected . (V)Sensor environmental conditions1. Minimum operating temperature ................................................ (°C)2. Maximum operating temperature ............................................... (°C)3. Average nominal operating temperature ..................................... (°C)4. Pollution degree ..............................................................................5. Over voltage category (from OV1 to OV3) .........................................6. Maximum ambient light level ......................................................(lux)7. Main reference standards ................................................................74S 0201。

测量热敏电阻的温度特性（Measure the temperaturecharacteristics of the thermistor）Experiment 8 measurement of resistance temperature characteristics of thermistorsExperimental purpose1. The relationship between thermistor and temperature is measured by thermometer and direct current bridge;2, grasp the relationship between the resistance value of NTC thermistor and temperature, and learn how to obtain empirical formula by data processing.Experimental instrumentTemperature sensor, temperature characteristic tester, resistance box, Dewar bottleExperimental principleThermistors are usually made of semiconducting materials, and their resistance varies sharply with temperature. Thermistor is divided into negative temperature coefficient (NTC), thermistor and positive temperature coefficient (PTC) thermistor two kinds. NTC thermistors are very small in size, and their resistance to temperature is much more sensitive than metal resistance. Therefore, it is widely used in temperature measurement, temperature control, temperature compensation in the circuit, time delay and so on. PTC thermistor is dividedinto two categories: ceramic PTC thermistor and organic material PTC thermistor. The PTC thermistor is a kind of new material resistor development in the early 1980s, it is characterized by the presence of a mutation point temperature, when the temperature of the material is more than the mutation point temperature, the resistance increased 5-6 orders (for example by 101 surged to over 107 ohms), so it has the application value of extremely wide.In recent years, our country has made great progress in the development and application of PTC Thermistor devices, PTC thermistor ceramics due to its large power and good heat resistance, has been applied in industries such as machinery, refrigerators for current overload protection,And can replace the nickel chromium electric heating wires as thermostatic heater and temperature control circuit for self heating type electric heater, a new automatic temperature control drying machine, all kinds of electric heater and a series of safe household appliances; and the thermal resistance of organic material PTC has short operation time, small volume, low resistance, has been used for domestic telephone switches, portable computer, portable cordless phones and otherhigh-tech fields for overload protection, a wide range of applications.The relationship between the experimental and the temperature measured by thermistor thermometer and DC bridge, mastering the characteristics, the relationship between the resistance and temperature of NTC thermistor and learn method through data processing to obtain the empirical formula.Resistance temperature characteristics of 1. negative temperature coefficient thermistorsNTC thermistor usually consists of Mg, Ni, Cr, Co, Fe, Cu and other metal oxides in 2-3 for pressing the mixture evenly, at the temperature of 600-1500oC sintering, the thermistor made of this kind of metal oxide semiconductor, has great negative temperature coefficient. In a certain temperature range, the relationship between the resistance and temperature of the NTC thermistor meets the following empirical formula:(1)In the formula, R is the resistance value of the thermistor at the thermodynamic temperature T, and R0 is the resistance value of the thermistor at the thermodynamic temperature T0. B is a material constant. It is not only related to the properties of the material, but also to temperature. In a small extent, B is a constant.The resistance temperature coefficient of NTC thermistor at thermodynamic temperature T0 can be obtained by (1) formula(2)By (2), the resistance temperature coefficient of the NTC thermistor is the quantity of square of the thermodynamic temperature, which is different at different temperatures.Pairs (1) with logarithms on both sides are obtainedIn a certain temperature range, and the linear relationship between the lnR, can be used for mapping method and least square method the value of slope B. The resistance temperature coefficient of NTC thermistor at a certain temperature is obtained by (2) formula.2. positive temperature coefficient thermistor resistance - temperature characteristics (selected content)The PTC thermistor has a unique resistance temperature characteristic, which is determined by its microstructure. When the temperature exceeds the PTC thermistor temperature change point, the material structure changed, its resistance value changes obviously, from 101 to 107 Omega Omega changes, PTC thermistor temperature is greater than the temperature when the resistance mutation changes with temperature in accordance with the following formula:(3)Among them, T is the thermodynamic temperature of the sample, T0 is the initial temperature, and R is the resistance value of the sample at the temperature T. R0 is the resistance value of the sample at the temperature T0, and the value of A is approximately constant in a certain range.The ceramic PTC thermistor, in less than the mutation point temperature, meet the relationship between resistance and temperature (1), the temperature coefficient is negative in nature, is greater than the mutation point temperature, meet(3), positive temperature coefficient thermistor, the mutation point temperature is often called the Curie point. Whereas for organic materials, PTC thermistors,At the temperature of the mutation point, both the positive and negative temperature coefficients are positive, but the constant A also has a sudden change at the mutation point, that is, the A value increases obviously when the temperature is higher than the mutation point.Experimental equipmentThe experimental equipment package thermostat, stirrer, thermometer, thermistor, small tube, resistance box three, a dry battery, galvanometer etc.. The thermistor is placed in a variable temperature thermostat and is measured with a thermometer. The resistance box, batteries, for galvanometer connection line into the bridge, to measure the resistance of the thermistor.Schematic diagram of experimental equipmentExperiment content and procedure1. the NTC thermistor and glass thermometer inserted in the glass filled with small tubes of transformer oil, controllable thermostatic bath tube is filled with water, when the NTC thermistor, glass thermometer and temperature balance, temperature of glass thermometer measured theta NTC thermistor, such as measuring circuit diagram of NTC thermistor the resistance of the R0 (Note: the current thermal resistanceshould be less than 300 A, avoid the influence of thermistor self heating on experimental measurement. At this point, the DC bridge arm can not strictly take the 1:1 ratio, the DC power supply maximum 1.5V)2. measured at room temperature (NTC thermistor thermometer inserted in water at room temperature and temperature) 6 and NTC thermistor R0. and then gradually increase the bath temperature, when the temperature reached stable when measuring a corresponding set of I and Ri theta value. The required temperature range from 70oC to 8-10. The data measured by the formula of T=273.15+ group theta, will be converted to Celsius temperature in T..ThreeThe material constant of temperature at room temperature 70oC range is obtained by the least square method B.4. calculate the resistance temperature coefficient of NTC thermistor at the temperature theta =50.0oC by formula (2)Experimental data exampleBridge arm RA, RB is the resistance box specifications for 0.1 0-9999 ohm, resistance box regulating resistor Rs for 0.10-9999.9, the power supply is 1.5V. at room temperature to 70oC range, the resistance value greater than 9000. So to meet the RT+Rs more than 5000 ohm, namely through the RT thermistor current is less than 300 A.Relationship between resistance and temperature of thermistor Serial numberRT/.T/KZero1163 x 10Nine point three six one threeTwo hundred and ninety-seven point six fiveThree point three five nine sevenZeroOneNine thousand four hundred and eighty-sixNine point one five seven sixThree hundred and three point five eightThree point two nine Four Zero-0.0657TwoSeven thousand three hundred and twenty-four Eight point eight nine eight nineThree hundred and eleven point eight five Three point two zero six seven-0.1530ThreeFive thousand one hundred and eighty-four Eight point five five three threeThree hundred and twenty-three Point Four Zero Three point zero nine two one-0.2676FourThree thousand seven hundred and forty-seven Eight point two two eight sevenThree hundred and thirty-five point four fourTwo point nine eight one two-0.3785FiveTwo thousand five hundred and sixty-fiveSeven point eight four nine sevenThree hundred and forty-eight point two sixTwo point eight seven one four-0.4883With Casio-3600 calculator for the least squares data processing, can be B=3.070 * 103K, lnR0=9.369.R0=1171 * 10 ohm. Correlation coefficient r=0.9995So, the empirical formula is:If you measure the temperature with this thermistor, you can only measure the resistance at this point, that is, you can count the temperature on the top, or the temperature on the graph。

Training and Practice for English for Academic PurposesPart I1.Discuss the following questions.What are basic principles the researchers must try to follow when they write their research papers? And would you please list some deadly sins a researcher must avoid when they want to publish a research paper? What are the main contents of a research paper?2. Translate the following Chinese introduction into English.提高起重机生产力和安全性的设备研究近些年来，就用研究人员对起重机(crane)的研究兴趣与日俱增。

起重机种类繁多，从樱桃采摘机(cherry pickers)到巨型塔式起重机(huge tower cranes) ，是建筑工地不可或缺的重要设备之一。

由于建筑用起重机工作环境多变(constantly changing working environment), 操作者(operator)责任重大(heavy reliance)。

过去几十年里，超重机技术日新月异，但是操作员与其他工种人员配合协作方面的技术发展缓慢。

起重机的发展步伐如此迅猛，我们似乎要问，在某些方面，是不是已经超出(outstrip)了人们安全使用的能力？本文旨在探讨如何通过新型设备的引进提高起重机生产力以及提出相关安全性的举措，进而为新型起重机的应用和案例提供新的思路。

In recent years, researchers have become more interested in crane research.The variety of cranes, from cherry pickers to giant tower cranes, is one of the most important equipment on construction sites.As a result of the changing working environment of the construction crane, operator is responsible for heavy reliance.Over the past few decades, the technology of overweight machines has been changing rapidly, but the operators have been slow to cooperate with other workers in collaboration.The pace of development of cranes is so rapid that we seem to be asking whether in some respects, the outstrip has exceeded the ability of people to safely use it.This paper aims to explore how to improve crane productivity and raise related security measures through the introduction of new equipment, so as to provide new ideas for the application and case of new cranes.3. You are writing a research paper entitled “The Effects of Radiation from the Sun on Life o n Earth”. In your introduction you need to review, in general terms, how the sun supports life on the earth. Prepare an Introduction section for your paper based on the information below.⏹Distance from the earth: 92,976,000 miles⏹The Sun’s energy comes from nuclear fusion of hydrogen to helium.⏹Intense radiation, including lethal ultraviolet radiation, arrives at the earth’s outer atmosphere.⏹Ozone in the stratosphere protects life on earth from excessive ultraviolet radiation.⏹The seasons of the earth’s climate results from (1) the 23.30tilt of the earth’s axis of rotation from the normal to the plane of the earth’s orbit around the Sun, (2) the large coverage area of water on the earth (about 75% of the earth’s surface), an d (3) the rotation of the earth with associated generation of jet-stream patterns.⏹Radiation passing through the earth’s atmosphere loses most short-wave radiation, butsome arriving at the surface is converted into infrared radiation which is then trapped by water vapor and other tri-atomic molecules in the troposphere and stratosphere, causing global warming.Life on earth is maintained from photosynthesis and conversion of carbon dioxide to oxygen by plants.4.Translate the following parts of sentences in Introduction into proper English.（1）过去对……的研究工作说明……The previous work on … has indicated that…（2）A在1932年做了关于……的早期研究。

热力学温度英文Thermodynamic temperature, also known as absolute temperature, is an important concept in thermodynamics. It is a measure of the average kinetic energy of the particles in a system, and it has a fundamental role in describing the behavior of matter at various temperatures.In thermodynamics, temperature is typically measured in the Kelvin (K) scale. The Kelvin scale is an absolute temperature scale, meaning it starts from absolute zero, which is the lowest possible temperature where all molecular motion ceases. On the Kelvin scale, the triple point of water is defined as 273.16K, and the temperature increases with the increase in the average kinetic energy of the molecules.One of the key principles of thermodynamics is the zeroth law of thermodynamics, which states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This allows the establishment of a temperature scale that can be used universally.Temperature can be measured using several different scales, such as Celsius and Fahrenheit, but these scales are relative to each other and can be converted to the Kelvin scale. The Celsius (°C) scale is defined by setting the boiling point of water at 100°C and the freezing point at 0°C under standard atmospheric pressure. Similarly, the Fahrenheit (°F) scale sets the freezing point of water at 32°F and the boiling point at 212°F. The Kelvin scale, on the other hand, is independent of the properties of any substance and is solely based on the principles of thermodynamics.The relationship between temperature and the average kinetic energy of the particles in a system is described by the kinetic theory of gases. According to this theory, as the temperature of a gas increases, the average kinetic energy of the gas particles also increases. This increased kinetic energy leads to a higher velocity and greater collisions between particles, resulting in increased pressure.Thermodynamic temperature is crucial in understanding many thermodynamic processes and laws. For example, the ideal gas law, which relates the pressure, volume, and temperature of a gas, is expressed using the Kelvin scale. Additionally, the second law of thermodynamics, which deals with the direction of heat flow and energy transfer, relies on the concept of temperature.Furthermore, temperature plays a crucial role in phase transitions, such as melting and boiling. These transitions occur at specific temperatures, known as melting and boiling points, where the average kinetic energy of the particles is sufficient to overcome the intermolecular forces holding them together.In conclusion, thermodynamic temperature is a fundamental concept in thermodynamics that measures the average kinetic energy of particles in a system. It is measured on the Kelvin scale and plays a crucial role in describing the behavior of matter at various temperatures. Understanding temperature is essential for comprehending the principles and laws of thermodynamics and is key to understanding the behavior of gases and phase transitions.。

晶体 (100) (001) 表面的定义1.晶体（100）（001）表面是晶体结构中重要的表面之一。

The (100) (001) surface is one of the important surfaces in crystal structure.2.这种表面的原子排布具有特定的方位和形貌。

The atomic arrangement on this surface has specific orientation and morphology.3.晶体的表面特征对其性质和应用有重要影响。

The surface characteristics of a crystal have a significant impact on its properties and applications.4.表面的结构决定了晶体在吸附、催化和生长等方面的行为。

The structure of the surface determines the behavior of crystals in adsorption, catalysis, and growth.5.人们通过研究晶体的表面特性来改进材料的性能和功能。

People study the surface characteristics of crystals to improve the performance and functionality of materials.6.表面的缺陷和形貌会影响晶体的稳定性和反应性。

Surface defects and morphology can affect the stability and reactivity of crystals.7.表面的能量和化学特性对晶体的形成和变化有重要影响。

The surface energy and chemical characteristics have a significant impact on the formation and transformation of crystals.8.表面的平整度和清洁度对晶体的品质和性能有直接影响。

以多途径热分析技术评估四种咪唑离子液体的分解特性和热危害摘要近年来，随着离子液体的广泛应用，其安全性和环境友好性成为研究热点。

咪唑离子液体是一种重要的离子液体，但其热性能和热危害尚未得到充分探究。

本文通过多途径热分析技术，对四种咪唑离子液体进行了评估分析，探究其分解特性和热危害。

结果表明，咪唑离子液体的热分解过程较为复杂，主要表现为两个阶段，第一个阶段为挥发分解，第二个阶段为热分解。

同时，各种咪唑离子液体的分解特性和热危害存在差异。

其中，2-羟基乙基三丁基咪唑氯铵、1-丁基-3-乙基咪唑氯铵和1-丁基-1-甲基咪唑氯铵的热稳定性较好，而丁基咪唑氯铵的热稳定性较差。

本研究提供的结果可为咪唑离子液体的安全评估和应用提供参考。

关键词：咪唑离子液体；热分析技术；热危害；分解特性；热稳定性AbstractIn recent years, with the widespread application of ionic liquids, their safety and environmental friendliness have become research hotspots. Imidazole ionic liquids are important ionic liquids, but theirthermal performance and thermal hazards have not been fully explored. In this paper, four kinds of imidazole ionic liquids were evaluated and analyzed by multi-path thermal analysis technology to explore their decomposition characteristics and thermal hazards. The results show that the thermal decomposition process of imidazole ionic liquids is relatively complex, mainly manifested in two stages. The first stage is volatilization and decomposition, and the second stage is thermal decomposition. At the same time, there are differences in the decomposition characteristics and thermal hazards of various imidazole ionic liquids. Among them, 2-hydroxyethyl tributyl imidazole chlorate, 1-butyl-3-ethyl imidazole chlorate and 1-butyl-1-methyl imidazole chlorate have better thermalstability, while butyl imidazole chlorate has poor thermal stability. The results provided in this study can provide a reference for the safety evaluation and application of imidazole ionic liquids.Keywords: imidazole ionic liquids; thermal analysis technology; thermal hazard; decomposition characteristics; thermal stabilityImidazole ionic liquids have received increasing attention due to their unique properties and potential applications in various fields. However, their thermalhazards and decomposition characteristics are important issues that need to be addressed in order to ensure their safe handling and application.Thermal analysis technology, including differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), provides effective methods for investigating the thermal properties of imidazoleionic liquids. In this study, several imidazole ionic liquids were analyzed using these techniques, andtheir thermal hazards and decompositioncharacteristics were evaluated.The results showed that the thermal stability of imidazole ionic liquids is highly dependent on their chemical structure. The presence of bulky alkyl groups and chlorine atoms in the imidazole cation can enhance the thermal stability of the ionic liquid. On the other hand, the presence of double bonds or unsaturated groups in the cation can decrease the thermal stability.Thermal hazard analysis revealed that some imidazole ionic liquids exhibit significant exothermic events during heating, indicating potential risks of thermal runaway. Careful handling and storage are necessary to minimize the risk of thermal decomposition andsubsequent hazards.In conclusion, this study provides valuableinformation on the thermal hazards and decomposition characteristics of imidazole ionic liquids, which is important for their safe handling and application. Further studies are needed to explore the relationship between the chemical structure and thermal properties of imidazole ionic liquids, and to develop strategies for improving their thermal stability and safetyOne important direction for future research on imidazole ionic liquids is to explore their potential applications in various fields, such as energy storage, catalysis, and separation. The unique properties of ionic liquids, such as their high conductivity, low volatility, and tunable polarity, make them promising candidates for these applications. However, thethermal stability and compatibility with other materials are critical factors that limit their practical use. Therefore, efforts should be made to design and synthesize imidazole ionic liquids with improved thermal stability and compatibility.Another important aspect that needs to be investigated is the environmental impact of imidazole ionic liquids. Although they are often touted as "green" solvents dueto their low volatility and non-toxicity, there isstill much to be understood about their fate and toxicity in the environment. Studies have shown that some ionic liquids can have adverse effects on aquatic organisms and soil microorganisms, which calls for a comprehensive evaluation of their environmental risks. Moreover, the biodegradability and recyclability of imidazole ionic liquids need to be assessed to determine their potential as sustainable alternatives to conventional solvents.Finally, it is worth noting that imidazole ionic liquids are just one type of ionic liquids, which are a rapidly expanding class of materials with diverse chemical structures and properties. There is still much to discover about their fundamental properties and potential applications, and it is likely that new classes of ionic liquids with even more unique and useful properties will be developed in the future. Therefore, continued research on imidazole ionic liquids and other ionic liquids is essential for advancing the field of green chemistry and developing sustainable technologies for a wide range of applicationsOne promising application for imidazole ionic liquids is in the area of energy storage. As the global demandfor energy continues to increase, there is a growing need for more efficient and sustainable energy storage technologies. One potential solution is the use of supercapacitors, which have the ability to store and release large amounts of energy quickly and efficiently.Imidazole ionic liquids have been shown to have excellent electrochemical properties, making themideal candidates for use in supercapacitors. They have high thermal stability, low volatility, and can be easily modified to enhance their properties. Additionally, they have a high ion conductivity and can be tailored to have specific capacitance and charge-discharge rates.Another potential application for imidazole ionic liquids is in the field of catalysis. Catalysts are critical for many industrial processes, including the production of fuels and chemicals, and the reduction of environmental pollutants. Imidazole ionic liquids have been shown to have unique catalytic properties, including high selectivity and activity, as well as the ability to function as both a solvent and a catalyst.One example of their potential use in catalysis is inthe production of biodiesel. Biodiesel is an alternative fuel made from vegetable oils or animal fats that has lower emissions and is more sustainable than traditional petroleum-based diesel. However, the production of biodiesel requires a catalyst, and many of the current catalysts are not optimal. Imidazole ionic liquids have been shown to be effectivecatalysts for the production of biodiesel, and could potentially lead to a more sustainable and efficient production process.In addition to their potential applications in energy storage and catalysis, imidazole ionic liquids also have potential uses in the fields of biotechnology, pharmaceuticals, and materials science. For example, they have been used as solvents for the extraction of biomolecules and as stabilizers for proteins and enzymes. They have also been investigated for use in drug delivery systems and as template materials for the synthesis of nanomaterials.Overall, imidazole ionic liquids are a promising class of compounds with diverse properties and potential applications. Research in this area is critical for advancing the field of green chemistry and developing sustainable technologies for a wide range of applications. In the future, it is likely that new andeven more unique classes of ionic liquids will be developed, further expanding the field of green chemistry and offering even more sustainable solutions to the world's energy and environmental challengesIn conclusion, liquids, especially ionic liquids, hold great promise for various applications in the field of green chemistry. Their diverse properties andpotential sustainability make them an appealing alternative to conventional solvents. Further research in this area is crucial to advancing sustainable technologies and addressing global energy and environmental challenges. With the development of even more unique and innovative classes of ionic liquids, the possibilities for green chemistry applicationswill continue to expand。

建筑热工设计气候分区English Answer：Building thermal design is a critical component of building design, as it can significantly impact the comfort and energy efficiency of a building. Climate data,including temperature, humidity, and precipitation, are key considerations in building thermal design. Climate data can be used to determine the appropriate thermal insulation levels, glazing types, and heating and cooling system requirements for a building.The climate of a region can be classified intodifferent climate zones, each with its unique set of thermal design requirements. Climate zones are typically based on factors such as temperature, humidity, and precipitation. Building codes and standards often include specific thermal design requirements for different climate zones.The use of climate data in building thermal design can result in significant energy savings. By designingbuildings to meet the specific thermal requirements oftheir climate zone, architects and engineers can reduce the need for heating and cooling, thereby reducing energy consumption. Climate data can also be used to design buildings that are more comfortable and healthy for occupants. By taking into account the thermalcharacteristics of a climate zone, architects and engineers can create buildings that are well-suited to the local climate and provide a comfortable living environment for occupants.Chinese Answer：建筑热工设计是建筑设计的一个关键组成部分，因为它会显著影响建筑的舒适度和能源效率。

考证热现象英文作文英文：When it comes to the study of heat phenomenon, thereare a lot of interesting things to explore. As for me, I am particularly interested in the concept of thermal equilibrium. This is the state where two objects that arein contact with each other have the same temperature. It is a very important concept in thermodynamics.One of the most fascinating things about thermal equilibrium is that it is a fundamental law of nature. Itis impossible for two objects to be in contact with each other and not reach thermal equilibrium. This is because heat always flows from hotter objects to colder objects. So, if two objects are at different temperatures and in contact with each other, heat will flow from the hotter object to the colder object until they both reach the same temperature.Another interesting thing about thermal equilibrium is that it can be used to measure temperature. For example, if you have a thermometer and you want to measure the temperature of a liquid, you can place the thermometer in the liquid and wait until it reaches thermal equilibrium with the liquid. Once the thermometer and the liquid are at the same temperature, you can read the temperature off the thermometer.Overall, the study of heat phenomenon is a fascinating field with many interesting concepts to explore. Whether you are interested in thermal equilibrium, heat transfer, or any other aspect of thermodynamics, there is always something new to learn and discover.中文：谈到热现象的研究，有很多有趣的事情可以探索。

热和热能的区别英语作文Title: Understanding the Distinction Between Heat and Thermal Energy。

Heat and thermal energy are often used interchangeably in everyday language, but in the realm of physics, they represent distinct concepts. This essay aims to elucidate the disparities between heat and thermal energy, shedding light on their definitions, properties, and applications.1. Definition and Nature:Heat refers to the transfer of thermal energy between objects due to a temperature difference. It flows from hotter regions to cooler ones until thermal equilibrium is achieved. The unit of heat is the joule (J) in the International System of Units (SI).Thermal energy, on the other hand, is the internal energy present in a system due to the motion andinteractions of its particles. It is a form of kinetic energy associated with the random motion of atoms and molecules within a substance. Thermal energy is also measured in joules (J) and is directly proportional to the temperature of the system.2. Characteristics:Heat is a transient phenomenon, dependent on the temperature gradient between two bodies and the thermal conductivity of the material through which it flows. It ceases to exist once thermal equilibrium is attained.Thermal energy, however, is an intrinsic property of matter and persists as long as the substance remains at a nonzero temperature. It represents the total kinetic energy of the particles within a system.3. Transfer Mechanisms:Heat transfer can occur through three primary mechanisms: conduction, convection, and radiation.Conduction involves the direct transfer of heat through physical contact between materials. Convection entails the transfer of heat through the movement of fluids (liquids or gases). Radiation involves the emission and absorption of electromagnetic waves, such as infrared radiation.Thermal energy transfer is fundamentally associatedwith the motion of particles within a substance. It occurs through collisions between particles at the microscopic level, leading to the transfer of kinetic energy fromhigher-energy particles to lower-energy ones.4. Measurement:Heat transfer is quantified based on the amount of energy transferred between two objects or systems. This is typically measured using calorimetry, which involves monitoring temperature changes resulting from heat exchange.Thermal energy, on the other hand, is measured based on the internal energy content of a system. This can be determined using various techniques, including calorimetry,thermodynamic analysis, and specific heat capacity measurements.5. Applications:Understanding the distinction between heat and thermal energy is crucial in various practical applications:Heat plays a vital role in processes such as cooking, heating, and refrigeration. It is harnessed in various industries, including manufacturing, energy production, and climate control.Thermal energy is central to the functioning of thermal power plants, where it is converted into mechanical energy to generate electricity. It is also utilized in heating systems, solar energy technologies, and thermal insulation materials.6. Conclusion:In conclusion, while heat and thermal energy areclosely related concepts, they represent distinct aspects of thermodynamics. Heat refers to the transfer of thermal energy between objects, driven by temperature differences, whereas thermal energy embodies the internal kinetic energy of particles within a system. Recognizing their disparities is essential for comprehending various natural phenomena and engineering applications.。

H2BTA的非等温热分解特性王亮亮;刘艳;赵守田【摘要】To detailedly understand the non isothermal thermal decomposition characteristics of N,N-bis-(1 (2)H tetrazol-5-yl)amine(H2BTA),the thermal decomposition characteristics at different heating rates and types of decomposition gas products and their content change for this compound were measured by means of TG-DSC-FTIR-MS and its thermal decomposition mechanism was analyzed.The results show that with the increase of temperature,the thermal decomposition of H2 BTA is divided into three successive processes:broking of tetrazole rings of the molecule began to release N2 mainly with the rapture of bond,the further rapture of bond in skeleton and release of N2,and the decomposition of residual skeleton with the expulsion of N2,NH3,HN3 and HCN.The apparent activation energies of the three processes are 187.19,142.32 and 198.93kJ/mol,respectively.%为详细了解N,N-二(1(2)氢-5-四唑基)胺(H2BTA)的非等温热分解特性,用热重-差式扫描量热-傅里叶红外光谱-质谱联用(TG-DSC-FTIR-MS)测定了该化合物在不同升温速率下的热分解特性、分解气体产物的种类及其含量变化,并分析了其热分解机理.结果表明,随着温度的升高,H2BTA的热分解分为3个连续的过程:(1)以-N-N-键断裂脱除N2为主的分子中四唑环裂解;(2)骨架中-N-N-键的进一步断裂释放N2;(3)剩余骨架裂解产生N2、NH3、HN3和HCN.3个分解过程表观活化能分别为187.19、142.32和198.93 kJ/mol.【期刊名称】《火炸药学报》【年(卷),期】2018(041)001【总页数】5页(P47-51)【关键词】N,N-二(1(2)氢5四唑基)胺;H2BTA;TG-DSC FTIR-MS联用;四唑含能化合物;热分解机理【作者】王亮亮;刘艳;赵守田【作者单位】防化研究院,北京102205;防化研究院,北京102205;防化研究院,北京102205【正文语种】中文【中图分类】TJ55;O642引言四唑类含能化合物是新型富氮含能化合物的典型代表之一，具有生成焓高、密度大、热稳定性高、产气量大、爆速和爆压高及燃烧或爆炸产物主要为无污染的N2等特性[1-3]，已成为国内外研究的热点[4-6]。

1.3 传热学基础传热学是一门研究在存在温差的物体间发生能量传递的科学。

热力学中将这种方式传递的能量定义为热量。

传热学不仅可以解释热量传递是如何传递的，而且可以计算在特定条件下的传热速率。

事实上，传热速率正是一个分析所期望的目标，它指明了传热学和热力学间的差别。

热力学处理的是平衡状态下的系统，它可计算当系统从一个平衡状态过渡到另一个平衡状态时所需要的能量，但不能解决系统处于过渡过程的非平衡状态时能量变化的快慢程度。

传热学提供了可用于计算传热速率的实验关联式，从而对热力学第一定律和第二定律进行补充。

这里，我们介绍热量传递的三种方式和不同型式的换热器。

1.3.1 Conduction heat transferWhen a temperature gradient exists in a body, experience has shown that there is an energy transfer from the high-temperature region to the low-temperature region. We say that the energy is transferred by conduction and that the heat transfer rate per unit area is proportional to the normal temperature gradient: q/A~∂T/∂x. When the proportionality constant is insertedT q A xλ∂=-∂ (1-3) Where q is the heat transfer rate and ∂T /∂x is the temperature gradient in the direction of heat flow. The positive constant λ is called the thermal conductivity of the material, and the minus sign is inserted so that the second principle of thermodynamics will be satisfied; i.e., heat must flow downhill on the temperature scale. Equation (1-3) is called Fourier ’s law of heat conduction after the French mathematical physicist Joseph Fourier, who made very significant contributions to the analytical treatment of conduction heat transfer. It is important to note that Equation (1-3) is the defining equation for the thermal conductivity and that λhas the units of watts per meter per Celsius degree in a typical system of units in which the heat flow is expressed in watts.1.3.1 热传导当物体内部存在温度梯度时，经验表明，就有能量从高温区向低温区传递。