scholarly journals Prediction of stability of drugs. IV. Prediction of stability by multilevel nonisothermal method.

1975 ◽  
Vol 23 (4) ◽  
pp. 803-809 ◽  
Author(s):  
NAOYA OKUSA
Keyword(s):  
2010 ◽  
Vol 48 (9) ◽  
pp. 932-939 ◽  
Author(s):  
Chia-Jung Tsai ◽  
Ming Chen ◽  
Hsin-Ying Lu ◽  
Wei-Che Chang ◽  
Chi He Chen

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Hongwei Fan ◽  
Yongliang Chen ◽  
Dongmei Huang ◽  
Guoqin Wang

The thermal decomposition of latex foam was investigated under nonisothermal conditions. Pieces of commercial mattress samples were subjected to thermogravimetric analysis (TG) over a heating range from 5°C min−1 to 20°C min−1. The morphology of the latex foam before and after combustion was observed by scanning electron microscopy (SEM), and the primary chemical composition was investigated via infrared spectroscopy (FT-IR). The kinetic mechanism and relevant parameters were calculated. Results indicate that the decomposition of latex foam in the three major degradation phases is controlled by third-order reaction (F3) and by Zhuravlev’s diffusion equation (D5). The mean E values of each phase as calculated according to a single heating rate nonisothermal method are equal to 41.91 ± 0.06 kJ mol−1, 86.32 ± 1.04 kJ mol−1, and 19.53 ± 0.11 kJ mol−1, respectively. Correspondingly, the preexponential factors of each phase are equal to 300.39 s−1, 2355.65 s−1, and 27.90 s−1, respectively. The mean activation energy E and preexponential factor A of latex foam estimated according to multiple heating rates and a nonisothermal method are 92.82 kJ mol−1 and 1.12 × 10−3 s−1, respectively.


2008 ◽  
Vol 128 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Bing LIN ◽  
Xian-Cheng ZHAN ◽  
Lin-Li LI ◽  
Cheng-Rong LI ◽  
Hai-Jun QI ◽  
...  

2009 ◽  
Vol 35 (2) ◽  
pp. 154-164 ◽  
Author(s):  
Bing Lin ◽  
Xian-Cheng Zhan ◽  
Jian-Lin Tao ◽  
Lin-Li Li ◽  
Hai-Jun Qi
Keyword(s):  

2005 ◽  
Vol 89 (2-3) ◽  
pp. 383-389 ◽  
Author(s):  
Ming-Der Ger ◽  
Yuh Sung ◽  
Jinn-Luh Ou

1977 ◽  
Vol 50 (5) ◽  
pp. 884-894
Author(s):  
J. M. Caruthers ◽  
R. E. Cohen

Abstract A nonisothermal creep experiment has been analyzed to ascertain its suitability for determining the temperature dependence of low-activation-energy viscoelastic processes in elastomers far above Tg. The nonisothermal method was employed to determine the activation energy for creep near 35°C in a lightly crosslinkedcis-1,4-polybutadiene elastomer at small strains within the linear viscoelastic region and at various large deformations up to rupture. The observed activation energy was essentially independent of the level of strain, and the value of ΔHa (∼ 11 kcal/mol) determined via the nonisothermal creep method was in good agreement with the result (∼12 kcal/mol) obtained via time-temperature superposition of isothermal linear viscoelastic creep data. The nonisothermal data allowed for an estimate of the volume of the “flow unit” associated with the controlling viscoelastic creep mechanism, attributed here to slippage of entanglements within lightly crosslinked network.


2010 ◽  
Vol 654-656 ◽  
pp. 1896-1899 ◽  
Author(s):  
Yun Feng Chang ◽  
Kung Hsu Hou ◽  
Ming Der Ger

The development of optical mold coatings has become a key technology in precision optical components in recent years. Researchers are still seeking ideal electroforming materials capable of resisting higher temperature and improve the lifespan of optical mold. Examples of these materials include Ni-W, and Ni-Mo-P alloy plating, among others. However, the literature rarely mentions these alloys as protective coatings. This may be because coating stability, flatness, and strength cannot achieve the desired protective effects. This study develops a combination of two wet electrochemical processes to form a multi-layer coating on optical molds. This coating consists of Ni-W, and Ni-Mo-P alloys. The proposed treatment process attempts to enhance the mechanical strength of the mold and extend its lifespan. We first used electro-deposition to form a thick-film Ni-W coating, and then applied the electroless plating by nonisothermal deposition method (NITD) to create a Ni-Mo-P thin-film and form a multi-layer coating. We also measured the composition, hardness, and elastic modulus of the protective coating as a reference basis for the development of optical molds. The results of this study reveal the appropriate process parameters to provide the multilayer films with a high strength and flat surface. This article can serve as a reference for the development of optical mold coatings.


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