共查询到18条相似文献,搜索用时 78 毫秒
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一种用于研究金属氢化反应的量热系统 总被引:1,自引:0,他引:1
将RD-1型量热计的样品管改装成能测量金属氢化反应热效应的量热系统,量热计常数经电能标定,峰高法和面积法所测结果的相对精度为0.5-1%。 相似文献
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反应焓变的测定是普通化学、无机化学教学的常规实验。实验用量热计大致可分为两种类型:即保温杯型[2~5]和烧杯夹泡沫塑料绝热型[5~7];采用的搅拌方法则有手握量热计摇动搅拌[1]、手握玻璃棒(或下端加环)上下移动或转动搅拌[2,3]、电动搅拌机搅拌或电磁搅拌器搅拌[5]。经过长期实践,已发现现有各种简易量热计存在如下问题:(1)搅拌过程中容易碰破量热计内壁或温度计;(2)手动搅拌不充分、不均匀,反应时间长,由此带来实验误差大;(3)烧杯夹泡沫塑料型量热计,在清洗过程中夹层容易进水,热容变化进而导… 相似文献
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RD-I型热导式自动量热计的研制 总被引:13,自引:1,他引:12
在文献[10]、[12]的基础上,研制了一种能在常温到150°C的较大温度范围内工作的“RD-Ⅰ型热导式自动量热计”。本文报导了仪器结构和工作原理。通过电能测定,证明仪器设计合理,工作正常。其性能完全符合Tian氏方程的要求。而且重现性好(相对精度为0.5%-1%左右),灵敏度高(对1卡以上的热效应能够准确地进行测量)。量热计通过光笔记录仪实现了测量记录的自动化。 相似文献
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The dynamic characteristics of an isoperibol solution calorimeter with electrical heating are discussed on a theoretical basis.The design requirements of a solution calorimeter are briefly reviewed. A calorimeter which satisfies these requirements was conducted and is described here. The dynamics of solutions heating by an electrical heater are mathematically developed and computer generated heating curves are compared to experimental curves. 相似文献
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A precision rotating-bomb combustion calorimeter in which thermistors were used as elements of temperature control and temperature measurement was constructed in our laboratory. The calorimeter was calibrated with benzoic acid of purity 99.999 percent. The energy equivalent of standard calorimeter system is 18.6376±0.0022 kJ.K~(-1). The precision of the experiment was 0.012% (shown in the form of 2s.d m) Detailed Washburn correction was made in microcomputer with programme designed by ourselves. 相似文献
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The design and properties of a double twin heat conduction microcalorimeter are described. In this instrument two twin microcalorimeters are placed close together, one on top of the other. The size of the instrument is the same as that of a commercial single twin microcalorimeter and each of the twin parts has similar properties as one normal twin microcalorimeter. The cross-talk between the calorimeters can be made low; we measured <0.1% of the signal generated in one calorimeter in the other calorimeter. This figure is, however, dependent on how well the two sides of the instrument are thermally balanced. The paper also contains a general discussion of the use of a reference in reducing the effect of temperature changes in the heat sink.
The advantage with a double calorimeter is that one may easily perform two related calorimetric experiments at the same time and in close proximity to each other, e.g. both sorption isotherms and sorption enthalpies may be measured simultaneously, or the heat production rate of a biological process may be monitored at the same time as the CO2 production is measured. 相似文献
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An aneroid isoperibol calorimetric apparatus is described which is particularly suitable for measurement of the reaction heat among solids. Such an apparatus contains four calorimeters and allows to carry out differential measurements. Each calorimeter includes two small electric furnaces employed for heating the solid mixture until the reaction begins and for the successive electric calibrations, respectively. The temperature trend of each calorimeter is followed by 80 thermocouples in series. The instrument characteristics are briefly discussed. Examples of its employment in the alloy thermochemistry are given. 相似文献
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Tan Zhi-Cheng Zhang Ji-Biao Shang-He Meng 《Journal of Thermal Analysis and Calorimetry》1999,55(1):283-289
A computerized adiabatic calorimeter for heat capacity measurements in the temperature range 80–400 K has been constructed.
The sample cell of the calorimeter, which is about 50 cm3 in internal volume, is equipped with a platinum resistance thermometer and surrounded by an adiabatic shield and a guard
shield. Two sets of 6-junction chromel-copel thermocouples are mounted between the cell and the shields to indicate the temperature
differences between them. The adiabatic conditions of the cell are automatically controlled by two sets of temperature controller.
The reliability of the calorimeter was verified through heat capacity measurements on the standard reference material α-Al2O3. The results agreed well with those of the National Bureau of Standards (NBS): within ±0.2% throughout the whole temperature
region. The heat capacities of high-purity graphite and polystyrene were precisely measured in the interval 260–370 K by using
the above-mentioned calorimeter. The results were tabulated and plotted and the thermal behavior of the two materials was
discussed in detail. Polynomial expressions for calculation of the heat capacities of the two substances are presented.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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A fully automated adiabatic calorimeter for heat capacity measurement between 80 and 400 K 总被引:1,自引:1,他引:0
Z. -C. Tan Q. Shi B. -P. Liu H. -T. Zhang 《Journal of Thermal Analysis and Calorimetry》2008,92(2):367-374
A fully automated adiabatic calorimeter controlled on line by a computer used for heat capacity measurements in the temperature
range from 80 to 400 K was constructed. The hardware of the calorimetric system consisted of a Data Acquisition/Switch Unit,
34970A Agilent, a 7 1/2 Digit Nano Volt /Micro Ohm Meter, 34420A Agilent, and a P4 computer. The software was developed according
to modern controlling theory. The adiabatic calorimeter consisted mainly of a sample cell equipped with a miniature platinum
resistance thermometer and an electric heater, two (inner and outer) adiabatic shields, two sets of six junction differential
thermocouple piles and a high vacuum can. A Lake Shore 340 Temperature Controller and the two sets of differential thermocouples
were used to control the adiabatic conditions between the cell and its surroundings. The reliability of the calorimeter was
verified by measuring the heat capacities of synthetic sapphire (α-Al2O3), Standard Reference Material 720. The deviation of the data obtained by this calorimeter from those published by NIST was
within ±0.1% in the temperature range from 80 to 400 K. 相似文献
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A new isothermal calorimeter, designed especially for simultaneously measuring the heat of reaction and the heat transfer data in a reaction solution, is described. The system, called a Constant Heat-Flux Calorimeter, is similar to a differential scanning calorimeter in terms of direct calorimetric measurement of the energies of reaction, but differs from the conventional calorimeters described in the literature. With this device, one recorded output in a temperature control circuit is a linear function of change in energies of reaction, and second in a differential temperature control circuit is found to be proportional to a resistance to heat transfer in a solution. The performance of the calorimeter was evaluated on the basis of some results on heat transfer data of aqueous solution of polyethylene glycol and on solution polymerization of styrene at constant temperatures. 相似文献