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Volume 8 (1981)
- Issue 4 Pages 131-
- Issue 3 Pages 91-
- Issue 2 Pages 47-
- Issue 1 Pages 2-
Volume 8, Issue 1
Displaying 1-6 of 6 articles from this issue
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Risaburo Yoshida, Akira Arikawa, Keisuke Kaiho, Osamu Ogawa1981 Volume 8 Issue 1 Pages 2-5
Published: January 30, 1981
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThe exothermic phenomena in the air oxidation of the mixture of sodium sulfide with carbonaceous materials were investigated by means of calorimetry.
Anhydrous sodium sulfide and three kinds of commercially available carbon blacks were used. The calorific values of the mixtures varied with the difference in the kind of carbon black used. Sodium sulfide in the mixture changed into sodium thiosulfate, sodium sulfite and sodium sulfate during the exothermic reaction.
Similar chemical changes on sodium sulfide were observed in aqueous sodium sulfide solution in which carbon black was dispersed.
From these results, it seems reasonable to assume that several kinds of functional groups, for example, carboxyl or phenol group on the surface of carbon black have great effects in the exothermic reaction.View full abstractDownload PDF (508K) -
Masao Taniguchi, Yong Mook Ham, Masataka Wakihara1981 Volume 8 Issue 1 Pages 6-13
Published: January 30, 1981
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThe equilibrium decomposition pressures of vanadium (IV) oxide sulfate (VOSO4) and the related thermodynamic data of thermal decompositions have been determined by a transpiration method and an electrochemical method using a ZrO2-CaO solid electrolyte.
The Gibbs energies for the reaction:
2VOSO4=V2O5+SO2+SO3 (1)
can be expressed by
ΔG°=329.1+0.36T(kJ) (680-863K).
Also the Gibbs energies for the reaction:
VOSO4=1/2V2O4+SO3 (2)
can be expressed by
ΔG°=204.2-0.21T(kJ) (843-863K).
Further, based upon the equilibrium decomposition pressure data for the thermal decompositions as mentioned above, SO2, SO3 and O2 partial pressure dependence on the decomposition reaction rate have been investigated by an isothermal weight-change determination method varing the atmosphere. The reaction (1) in 1atm N2 and SO2-SO3-N2 (490-520°C), and O2-N2 (450-500°C) atmospheres was explained by a contracting cube model kinetic equation and both SO2-SO3 and O2 partial pressure dependence were clearly obtained. The reaction (2) in 1atm SO2 atmosphere (570-591°C) was explained by Avrami-Erofeev kinetic equation. The activation energies were also discussed.View full abstractDownload PDF (893K) -
Shigeyuki Tanaka, Yoshihiro Baba, Akihiko Kagemoto, Ryoichi Fujishiro1981 Volume 8 Issue 1 Pages 14-18
Published: January 30, 1981
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThe influence of metallic ions such as Cd2+, Cu2+ and Hg2+ on the poly (A)·poly (U) duplex formed by an equimolar mixture of poly (A) and poly (U) was studied by using a modified differential scanning calorimeter (DSC) with a help of the spectral measurements.
The transition temperature, T1, of poly (A)·poly (U) duplex shows a definite value of about 315K which is nearly independent of r (the mole ratio of metallic ion to phosphate in polynucleotide).
While, the dependence of the heat of helix-coil transition, ΔH, on r was divided into two cases: in the first case, when r is less than 10-2, ΔH for Cu2+ and Cd2+ systems increases with an increase of r, but ΔH for Hg2+ system is a definite value which is nearly independent of r. In the second case, when r is in excess of 10-2, ΔH for all systems shows a drastic decrease as r increases.
From the results of spectral measurements obtained, poly (A)·poly (U) duplex seems to form a complex with Cu2+ or Hg2+ at room temperature when r is more than 10-2 except for Cd2+ system, and random coil structure of poly (A) and poly (U) obtained in which are the helix-coil transition of poly (A)·poly (U) duplex interacts also with metallic ions, and its interaction is expected to be exothermic. While, the behavior for Cd2+ system is the same to that of Cu2+ or Hg2+ system. However, the effects of poly (A)·poly (U) duplex on Cd2+ may differ from those of Cu2+ or Hg2+ systems.View full abstractDownload PDF (537K) -
Kazumasa Matusita, Sumio Sakka1981 Volume 8 Issue 1 Pages 19-21
Published: January 30, 1981
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSThe method for analyzing crystallization kinetics by DSC was discussed on the basis of nucleation and growth equations. It was found that crystallization mechanism, that is, whether bulk crystallization or surface crystallization occurs, is very important for obtaining the meaningful activation energy. This was ascertained by applying the analytical formulae to the crystallization of Li2O·2SiO2 glass of which kinetic data on crystallization were already well known. It was also found that the so-called Kissinger plot is valid only when crystallization starts at the surface and growth progresses towards the inside of the glass one-dimensionally. It was concluded that the crystallization mechanism should be known in order to obtain the meaningful activation energy.View full abstractDownload PDF (364K) -
Rikio Yokota, Masazumi Akiyama, Hirotaro Kambe1981 Volume 8 Issue 1 Pages 22-26
Published: January 30, 1981
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDynamic mechanical properties of composites, glass reinforced aromatic polyamideimide and BT resin, were measured by means of flextural osillation with a du pont 980 Dynamic Mechanical Analyzer (DMA), and tensile osillations with a Rheovibron DDV-II-C were used for comparison.
Corresponding molecular relaxations were found for each osillation mode.
It was found that flextural osillation mode (DMA) is particularly sensitive for a part of composites with low rigidity, while tensile osillation mode is susceptive for a part of composites with high rigidity.
DMA is especially well suited for study of dynamic mechanical properties of polymer composites.View full abstractDownload PDF (465K) -
(5) Principle and application of thermomechanical analysisShigeo Nakamura1981 Volume 8 Issue 1 Pages 27-34
Published: January 30, 1981
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDownload PDF (1030K)
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