在放热过程中对半导体热电偶测量数据进行数值分析中英文翻译资料.doc

在放热过程中对半导体热电偶测量数据进行数值分析在回收实验样品后，并对其分析后得出，在高压下快速凝聚物质是观察物质物理性质和化学性质的动态趋势的重要基础。在许多情况下不可能用一个特制的容器来存某种物质的特定状态，所以会直接关系到冲击波脉冲的物理参数变化。所以方法要求，人们尽可能的继续保持对胶囊内物质进行抽样，并同时冲击波要检测物质，而且处在长时间的放松状态。人们还应该记住，冲击波检测胶囊实验是不同于纯动态实验。基于这个原因，两种方法所得到的结果简单的比较可得出许多的不正确和不足，特别是在研究某种物质的化学变化。用冲击波检测物质的方法，是根据某些问题而相互结合的动态方法，解决了传统的回收凝聚物质的方法。在放热的过程中记录半导体的热电现象就是这样的一个方法。别的的文章中仅仅只是涉及到对半导体热电偶的原理的运用。这些显然不足以获得有关连续变量的信息。本文对此提出了建议用计算方法来分析问题的一般方法，并为活性强的元素制订解决方案其中锡是用（sns）来解决。在对实验过程中所记录的半导体热电偶的放热图中，根据敏感元件内部的结构研究利用电平测量内部电极的结构，该电极通过平版石灰岩绝缘套管来连接的。在冲击波实验装置中增加负荷使其速度高于1公里/秒（箭头方向表示物体的运动方向）。在动态压力下降时，舱内温度呈现一定分布，是随时间变化而分布，是为了测量电路的电磁场而发生的。假设电磁场是由于半导体的存在可得： s是半导体的热电势，ts1是热电偶的内部电极的温度; ts2是热电偶外部界面的温度。符号的意义是热电偶的内部电极与外部界面之间的温差。因此，该电路（存在接地电极情况下）如果0而且，那么就0。当半导体热电偶没有放热过程，那么电磁场就下降到零，因为冷却的热电偶不存在电磁场。原因是在热释放过程中，将有一定的电磁场增长下降到零之后，化学反应就会停止。所以本文对此提出了建议用计算方法来分析问题的一般方法，并为活性强的元素制订解决方案其中锡是用（sns）来解决。如果电极两端的电压接近，那它就会被记录，如果满足电阻值，是测量设备的输入电阻和是样品的内部电阻。如果= 50或75在冲击波实验中就会被使用，很容易得出研究物质的电导率和可直接测量半导体材的数值。原则上，样品可以被放置一个的金属箔内与排除样品之间产生的热电偶热惯性低电极的电路。在实验中，我们进行了合成反应合成了放热过程的超导材料陶瓷。热电偶是由活性较强的锡做成，这是一个热电功率为的半导体。按照规定，实验中的几何参数为：，。用冲击波轰击5mm厚的铁板所产生的压强为16gp。最初的样本显示：混合物由于存在高含量的单质铜导致导电性较高。该热电偶电阻不会使整个录音期间0.1re信号衰减。要使u随时间t而变化，我们使用了能自动记录数据的f4226转换器把模拟信号转换成数字信号，在允许你改变扫描速度的基础上，缩短周期。从示波器上的波形可知，冲击波载荷着能使半导体进行化学反应的负脉冲。该过程可进一步解释为：在热释放状态时，样本加热反应的情况下热释放产生了一个极性为正极的信号。事实上，这种脉冲必须是正极的，可从公式成立的条件解释：（所研究的混合物中含有活性较强的锡是用sns来解决）和s 0 。其次，约17毫秒后，冲击波进入样品，由于放热反应使ts2的值增加。在电压上升时，使它在一段时间内下降（这可能是因为在合成过程中形成了低电导率的中间产品）。因此会变得比更大。作为最终产品的形式最初的高导电性也会恢复，因此，随着的增长。最后，降低了冷却时间。很显然，要得知示波器为什么会产生这样波形，就必须建立数学模型对电物理过程进行仿真实验。即使是在一个平面内，也是一个复杂的问题，其中一个必须要解决的是不稳定的情况下的导热方程，也要考虑到在该样本中的导电性能的变化等等。在本论文中，我们考虑的一个关系到如何分析锡半导体热电偶操作数值的特殊情况。在这里，反应系统模型为放热过程，不同比例的锡和硫的混合也可运用与sns。外文文献翻译原文2of semiconductor thermocouple operation in recording exothermic processes in a recovery capsules. s. nabatov, a. v. kulbachevskii, and a. v. lebedev udc 539.63+537.226numerical simulation is used to analyze the operation of a semiconductor tin-monosulfidethermocoupie. the element is used to record ezothermic processes in shock-recovery experiments.we solved the problem in a one-dimensional formulation by considering a multilayer schemethat models the location of the sample and the thermocouple inside a real flat capsule. numericalcalculations yield time dependences of the thermal electromotive force (emf) at various heatreleaserates in the substance under studyhigh-speed methods of studying the properties of condensed material under shock compression and shock-recovery experiments with subsequent analysis of the samples are the basis of the dynamic trend in high-pressure physics and chemistry 1. in many cases, however, there are no sufficient grounds to assert that the state of the substance recovered in a special capsule is related directly to the changes in the physical parameters recorded in the shock-wave pulse. methods are required that make it possible to continuously keep track of the behavior of the sample inside the capsule, starting with the moment when the shock wave enters the substance, and then for a long period of time in the relaxed state. one should also bear in mind that the shock-wave action in a capsule can differ significantly from loading in a pure dynamic experiment. for this reason, a simple comparison of the results obtained by both methods is not correct enough, particularly in studies of shock-induced chemical transformations in heterogeneous media.according to 2, this problem should be solved by various combined methods: dynamic methods, conventional recovery methods, and a new methodical approach based on continuous diagnostics of a substance inside a capsule using electrical methods. recording of exothermal processes based on the thermoelectric phenomenon in semiconductors is one such method 3. the latter article, however, deals only with the principles of operation of a semiconductor thermocouple. these are obviously insufficient to obtain quantitative information on the transformations in question. the present paper considers a general approach to the formulation of numerical-analysis problems for the suggested method and presents solution results for asensitive element in which tin monosulfide (sns) is used.a diagram of experiments on the recording of exothermal processes in a recovery capsule with a semiconductor thermocouple is presented in fig. 1. substance 4 under study with sensitive element 5 are placed inside a flat capsule for electric measurements between the front wall of case 1 and massive inside electrode 2. the electrode is insulated from the case by sleeve 3 made of lithographic limestone. shock-wave loading of the experimental setup is produced by an aluminum striker accelerated by an explosion to velocities higher than 1 km/sec (the arrows show the direction of the action). after a drop in dynamic pressure, there is a certain distribution of temperature t inside the capsule. the distribution changes with time and is responsible for the occurrence of emf e in the measuring circuit. assuming that the main contribution to the emf is due to the presence of the semiconductor thermocouple, in the ideally plane case, we havewhere s is the thermoelectric power of the semiconductor; tsl is the temperature at the interface between the thermocouple and the internal electrode; ts2 is the temperature at the interface between the sample and the thermocouple. the sign of the registered signal is determined by the sign of s and that of the temperature difference between the faces of the thermocoup.le. thus, for this circuit (grounded electrode-capsule case) /e 0 if s(t) 0 and ts2 tsl. when there is no exothermal process in the sample, the emf drops to zero because of cooling of the thermocouple and the substance under study. in the case of heat release due to, for example, a chemical reaction, there will be some growth in emf followed by a decrease to zero. if the voltage u across the electrodes is close to ae, it can only be recorded if the condition re ri is satisfied, where re is the input resistance of the measuring device, and ri is the internal resistance of the experimental unit. since re = 50 or 75 are used in shock-wave experiments, it is easy to estimate the electrical conductivities of the studied substance and the semiconductor material for which the quantity ae can be measured directly. in principle, the sample can be excluded from the electrical circuit by placing an additional foil electrode with low heat inertia between the sample and the thermocouple.figure 2 presents an oscilloscope trace that demonstrates the possibilities of the method. in theexperiment, we registered the synthesis reaction (exothermal process) for superconducting cuatibytcoa ceramics. the thermocouple was made of tin monosulfide, which is a semiconductor compound with a thermoelectric power of +550 #v/k under normal conditions. in accordance with the notation in fig. 1,the geometric parameters of the experimental arrangement were as follows: i1 = 7 ram, 12 = 13 = 1 ram, and /4 = 16 ram. the amplitude of the shock wave generated inside the steel wall of the capsule by a striker 5 mmthick was 16 gpa. the initial sample showed a high electrical conductivity, because of the presence of free copper in the pressed mixture. the resistance of the thermocouple did not exceed 0.1re throughout the period of signal recording. to register the dependence of u on time t, we used an automated recording system based on an f4226 analog-to-digital converter, which allows one to change the sweep rate discretely, decreasing it with time 4. as is seen from the oscilloscope trace, the shock-wave loading of the cell generates negative pulses that are the response of the semiconductor substance to the shock-wave action 5. the further behavior of the record can be explained as follows. in the released state, a signal of positive polarity forms which is caused by residual heating of the cell in the absence of heat release due to the reaction in the sample. the fact that this pulse must be positive can be inferred from the following conditions see the explanations for formula (1): ts2 tsl (the studied mixture and sns are heated more strongly in comparison with the capsule material) and s 0. next, about 17 msec after the shock wave enters the sample, a second positive signalfollows, which is caused by an increase in ts2 due to the exothermai reaction. the rise in voltage, however, is followed by its drop for some time (this is probably due to the fact that intermediate products with a low electrical conductivity are formed in the process of synthesis). as a result, ri becomes much greater than re. as the final product forms, the initial high electrical conductivity is restored and, accordingly, u grows. finally, the signal decreases, because of cooling of the cell.it is obvious that for detailed interpretation of such oscilloscope traces, one must supplement the experimental results by a mathematical simulation of the registered electrophysical processes. in a general formulation even for the plane variant, this is an involved problem, in which one must solve nonstationary heatconduction equations with varying parameters, choose kinetic dependences describing the chemical interaction, take into account the change in the electrical properties of the sample, and so forth. in the present paper, we consider a particular case of the problem related to the numerical analysis of the operation of a tin-monosulfide semiconductor thermocouple. here, the reacting system which models an exothermal process is a mixture of tin and sulfur in a stoichiometric proportion that corresponds to the synthesis of sns.references1. g. a. adadurov, t. v. bavina, o. n. breusov, et al., on the relationship between the state ofmaterial under dynamic compression and results of studies of recovered samples, in: combustion and ezplosion: proc. of the 3rd ussr symp. on combustion and explosion in russian, nauka, moscow (1972), pp. 523-528.2. s. s. nabatov, g. e. ivanchikhina, a. v. kolesnikov, et al., shock-wave synthesis of tin monosulfide, khim. fiz., 14, nos. 2 and 3, 40-48 (1995).3. s. s. nabatov, s. o. shubitidze, and v. v. yakushev, use of the thermal emf phenomenon insemiconductors to study exothermal processes in a recovery capsule, fiz. goreniya vzryva, 26,no. 6, 114-116 (1990)4. a. v. lebedev, s. s. nabatov, and t. a. alekseenko, a measuring complex based on an f4226 analog-to-digital converter and its use for recording of electrical parameters in shock-wave recovery expe