Thermal stability of bimetallic Au/Fe nanoparticles in silica matrix

2014 ◽  
Author(s):  
Compesh Pannu ◽  
Udai B. Singh ◽  
Sonu Hooda ◽  
D. Kabiraj ◽  
D. K. Avasthi
Pharmaceutics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 228 ◽  
Author(s):  
Ekaterina S. Dolinina ◽  
Elizaveta Yu. Akimsheva ◽  
Elena V. Parfenyuk

Powerful antioxidant α-lipoic acid (LA) is easily degraded under light and heating. This creates difficulties in its manufacture, storage and reduces efficiency and safety of the drug. The purpose of this work was to synthesize novel silica-based composites of LA and evaluate their ability to increase photo and thermal stability of the drug. It was assumed that the drug stabilization can be achieved due to LA-silica interactions. Therefore, the composites of LA with unmodified and organomodified silica matrixes were synthesized by sol-gel method at the synthesis pH below or above the pKa of the drug. The effects of silica matrix modification and the synthesis pH on the LA-silica interactions and kinetics of photo and thermal degradation of LA in the composites were studied. The nature of the interactions was revealed by FTIR spectroscopy. It was found that the rate of thermal degradation of the drug in the composites was significantly lower compared to free LA and mainly determined by the LA-silica interactions. However, photodegradation of LA in the composites under UV irradiation was either close to that for free drug or significantly more rapid. It was shown that kinetics of photodegradation was independent of the interactions and likely determined by physical properties of surface of the composite particles (porosity and reflectivity). The most promising composites for further development of novel silica-based formulations were identified.


2010 ◽  
Vol 120 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Gaorui Ren ◽  
Hong Qiu ◽  
Qing Wu ◽  
Hui Li ◽  
Huili Fan ◽  
...  

2011 ◽  
Vol 239-242 ◽  
pp. 294-297
Author(s):  
Cun Jin Xu ◽  
Qun Lü ◽  
Hai Ke Feng

A ternary Eu(III) complex with salicylic acid (Hsal) ando-phenanthroline (phen) was synthesized and then incorporated into silica matrix by sol-gel method. The luminescence behavior of the complex in silica gel was studied compared with that of the pure complex by means of emission, excitation spectra and thermogravimetic analysis. The results indicate that the complex Eu(sal)3(phen) in silica gel shows fewer emission lines than pure Eu(sal)3(phen) and the luminescence intensity ratio of the5D0→7F2transition to the5D0→7F1transition is lower than that of the latter. The thermal stability of Eu(sal)3(phen) is enhanced greatly through the introduction of the complex into silica matrix.


2001 ◽  
Vol 36 (7-8) ◽  
pp. 1335-1346 ◽  
Author(s):  
Bao-li An ◽  
Jian-qing Ye ◽  
Meng-lian Gong ◽  
Xian-hong Yin ◽  
Yan-sheng Yang ◽  
...  

Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization


Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.


1991 ◽  
Vol 1 (12) ◽  
pp. 1823-1836 ◽  
Author(s):  
M. Bessière ◽  
A. Quivy ◽  
S. Lefebvre ◽  
J. Devaud-Rzepski ◽  
Y. Calvayrac

1994 ◽  
Vol 4 (4) ◽  
pp. 653-657
Author(s):  
B. Bonzi ◽  
M. El Khomssi ◽  
H. Lanchon-Ducauquis

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-63-Pr2-66 ◽  
Author(s):  
R. Varga ◽  
P. Vojtaník ◽  
A. Lovas

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