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Volume 7 (1980)
- Issue 4 Pages 107-
- Issue 3 Pages 67-
- Issue 2 Pages 37-
- Issue 1 Pages 2-
Volume 7, Issue 4
Displaying 1-3 of 3 articles from this issue
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Yoichi Takahashi, Tadahiko Azumi, Jin-ichi Nakamura, Masayuki Kamimoto1980 Volume 7 Issue 4 Pages 107-111
Published: October 15, 1980
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSA new isoperibol type calorimeter for laser-flash heat capacity measurement over the temperature range from 80 to 300K is described. In the new calorimeter the sample is surrounded by a heat sink made of copper, of which temperature is kept nearly the same as that of the sample; thus the heat loss from the sample is considerably diminished. The temperature of the heat sink is detected by a Minco platinum resistance thermometer, and the temperature difference between the heat sink and the sample is sensed by a copperconstantan thermocouple. In this way, the temperature of the sample can be determined with an inaccuracy of ±0.01K, which is much better than that of ±0.2K for the conventional laser-flash calorimeter using thermocouple as the temperature sensor. In order to test the reliability of the calorimeter, the heat capacity of the α-alumina single crystal was measured from 80 to 300K. The results were compared with the N. B. S. data, and the standard deviation was ±0.28%. The imprecision and the inaccuracy of the heat-capacity measurement using this calorimeter are estimated to be within ±0.3% and ±0.5%, respectively.View full abstractDownload PDF (1217K) -
Keiichi Moriya, Takasuke Matsuo, Hiroshi Suga1980 Volume 7 Issue 4 Pages 112-116
Published: October 15, 1980
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSAn adiabatic low temperature calorimeter with a built-in cryorefrigerator has been constructed. Care was taken in the design to mechanically isolate the calorimeter from the refrigerator whose vibration would otherwise interfere the performance of the calorimeter. The refrigerator worked either to simply cool the calorimeter to 16K or to liquefy hydrogen in the cryostat which was thereafter cooled to 13K by evacuation of the liquid hydrogen. The results of heat capacity measurements on benzoic acid as a standard material showed deviations from the statistical average of several published data of less than 2% between 13.81 and 20K, about 0.5% between 20 and 60K, less than 0.1% between 60 and 275K and less than 0.2% between 275 and 340K. The scattering of the experimental points from a smooth curve was substantially less than the inaccuracy, ranging from 1.0 to 0.05% depending on the temperature.View full abstractDownload PDF (1135K) -
Kazuko S. Kunihisa1980 Volume 7 Issue 4 Pages 117-127
Published: October 15, 1980
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThermotropic liquid crystalline phases and the polymorphs are reviewed. 1, Reentrant behaviors mainly related to nematic phase and the thermodynamical conditions. 2, Blue cholesteric phase and the polymorphs. 3, Two stage phenomenon at a cholesteric-smectic transtion. 4, Polymorphs of smectic phase including two new phases. 5, Discotic mesophase and the polymorphs. 6, Intermediate solid polymorphs and impurities. 7, Liquid crystalline mixtures (Binary system of aliphatic esters of cholesterol).View full abstractDownload PDF (3122K)
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