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Electrohydrodynamic instability in homeotropically oriented nematic samples of 4'-n-octyl-4-cyano-biphenyl and 4'n-alkyloxy-4-cyanobiphenyl, (n = 8.9) have been studied in an a.c. electric field. The domain patterns during the instability in these compounds in a very low frequency a.c. field are very similar to those in a d.c. field. The domain patterns observed at higher frequencies have been identified as 'maltese crosses' or 'crossed isogyres'. The electro-convective 'isotropic' flows near the electrode play an important role in the observed instability. 相似文献
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Sabyasachi Gaan 《Polymer Degradation and Stability》2007,92(6):968-974
The effect of six organophosphorus compounds, including Pyrovatex CP (PCP), diammonium phosphate (DAP), phosphoric acid (PA), tributyl phosphate (TBP), triallyl phosphate (TAP) and triallyl phosphoric triamide (TPT) on the flame retardancy of cotton cellulose was studied. PCP, PA, and DAP are more efficient compared with the other three compounds in improving the limiting oxygen index (LOI) of cotton. The effectiveness of these compounds was investigated using scanning electron microscope (SEM) images of char formed after LOI tests, char content, activation energy of decomposition and heat of combustion data. SEM images showed that DAP, PCP and PA chars maintain the surface morphology during the burning process, which might be due to the formation of a protective layer or crosslinking effect. PA, PCP, and DAP treated fabrics have a higher activation energy of decomposition, higher char content and lower heat of combustion. 相似文献
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Anuradha Rout Swoyam P. Rout Nigamananda Mallick Baishnab C. Singh M. Santappa 《Journal of polymer science. Part A, Polymer chemistry》1978,16(2):391-397
The polymerization of acrylonitrile (M) initiated by the Ce(IV)–acetophenone (AP) redox pair has been studied in acetic–sulfuric acid mixtures in a nitrogen atmosphere. The rate of polymerization is proportional to [M]3/2, [AP]1/2 and [Ce(IV)]1/2. The rate of disappearance of ceric ion,–RCe, is proportional to [AP], [M], and [Ce(IV)]. The effect of certain salts, solvent, acid and temperature on both the rates have been investigated. A suitable kinetic scheme has been proposed, and the composite rate constants kp 2(k/k/t) and k0/ki are reported. 相似文献
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K. A. Sree Raj Afsal S. Shajahan Dr. Brahmananda Chakraborty Dr. Chandra Sekhar Rout 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6662-6669
In this work, the ternary hybrid structure VSe2/SWCNTs/rGO is reported for supercapacitor applications. The ternary composite exhibits a high specific capacitance of 450 F g−1 in a symmetric cell configuration, with maximum energy density of 131.4 Wh kg−1 and power density of 27.49 kW kg−1. The ternary hybrid also shows a cyclic stability of 91 % after 5000 cycles. Extensive density functional theory (DFT) simulations on the structure as well as on the electronic properties of the binary hybrid structure VSe2/SWCNTs and the ternary hybrid structure VSe2/SWCNTs/rGO have been carried out. Due to a synergic effect, there are enhanced density of states near the Fermi level and higher quantum capacitance for the hybrid ternary structure compared to VSe2/SWCNTs, leading to higher energy and power density for VSe2/SWCNTs/rGO, supporting our experimental observation. Computed diffusion energy barrier of electrolyte ions (K+) predicts that ions move faster in the ternary structure, providing higher charge storage performance. 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - A simple normal-phase high-performance thin-layer chromatography (HPTLC) method has been developed for the quantification of... 相似文献
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