Measurement of Very High Pressure Using The Pressure Effect on The EMF of Thermocouples.

(1)采用高精度电动势测量仪和个人计算机组成了测量和数据处理系统，根据高压空间中常用热结上两种热电偶（Alumel/Chromel和Pt/Pt10%Rh）测量的视温差（已知压力效应），对立方体顶锤装置中产生的压力进行了评估。压力输出的周期可以选择为1到6秒，这意味着实现了有效的实时测量。评估的压力包含一个随机噪声，振幅为（]SY.+- [）0.2 GPa，这可能是由电动势测量中的热噪声引起的。然而，通过平滑技术减少了噪声，其中最可能的值是通过一种最小二乘法处理过去的50-100个值来计算的。因此，压力检测的分辨率为0.02 ~ 0.05 GPa。(2)设计并完成了一种校正eva…的方法，该方法应受“失压效应”的影响，这取决于热电偶导线引入压力空间时的温度Tm （60 ~ 80 C）。当热结温度为600 ~ 700ºC时，校正量为10 ~ 20%。(3)本研究实现了一种通过铁砧测量热电偶电动势的新方法，该方法可以精确地知道铁砧的顶面温度Tm，并且可以在1ºC范围内测量。该方法允许使用细导线，并消除了由热结周围的温度梯度引起的误差（假压力效应和传统导线引入方法的主要误差）。一个新的严重的误差（约1 GPa）是由砧的Tm的差异带来的。然而，只要知道每个铁砧的Tm，就可以完全消除它。(4)目前已成功实现了相对压力评价的目标，分辨率为0.02 ~ 0.05 GPa。(5)在热结温度不超过700ºC的情况下，热电偶可以稳定测量10小时以上。(6)评价压力绝对值的系统误差最大可达1 GPa，不同实验间存在差异。然而，对于这个问题，原因和下一阶段的解决办法已经明确。少

(1) A Measurement and data processing system was composed of a high precision emf measuring instrument and a personal computer, and genarated pressure in a cubic anvil apparatus was evaluated based on the difference (known pressure effect) in apparent temperatures measured by the two kinds of thermocouples (Alumel/Chromel and Pt/Pt10%Rh) on a common hot junction in the high pressure space. The period of the pressure output could be selected as one to six seconds, which means attainment of an effectively real-time measurement. The evaluated pressure contained a random noise of an amplitude of (]SY.+-。[)0.2 GPa, which might be caused by the thermal noise in the emf measurement. The noise was, however, reduced by a smoothing technique, in which the most probable value was calculated by processing past 50-100 values with a kind of the least-square method. Thus the resolution of 0.02-0.05 GPa was attained in detection of pressure.(2) A method was devised and completed for correcting the eva … More luated pressure which should be affected by the "lost pressure effect" dependent on the temperature Tm (60 to 80ﾟC) at which the thermocouple wires are lead-in to the pressure space. The correction amounted to 10-20%, if the hot junction temperature was 600 to 700ﾟC.(3) In the present study a new method was realized for measuring the thermocouple emf through the anvils, where the top face temperature of the anvil Tm should be known precisely, and could be measured within 1ﾟC.The method allowed to use a thin wire and resulted in eliminating an error caused by a temperature gradient around the hot junction (spurious pressure effect and the main error in the conventional method of leading-in the wire). A new serious error (of around 1 GPa) was brought in from difference in Tm's of anvils. It is, however, expected to be eliminated completely by knowing Tm for each anvil.(4) At the present stage an object of relative pressure evaluation was successfully attained with a resolution of 0.02 to 0.05 GPa.(5) It was revealed that degradation of the thermocouples was avoided and very stable measurement was possible for more than 10 hours, if the hot junction temperature did not exceed 700ﾟC.(6) Absolute value of the evaluated pressure contained a systematic error of up to 1 GPa, different from experiment to experiment. For this problem, however, the cause and the solution in the next stage has been made clear. Less