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排序方式: 共有611条查询结果,搜索用时 203 毫秒
61.
Ashutosh Tiwari Rajendra Kumar Mani Prabaharan Ravi R. Pandey Premlata Kumari Anurag Chaturvedi A. K. Mishra 《先进技术聚合物》2010,21(9):615-620
A nanofibrous polyaniline (PANI) thin film was fabricated using plasma‐induced polymerization method and explored its application in the fabrication of NO2 gas sensor. The effects of substrate position, pressure, and the number of plasma pulses on the PANI film growth rate were monitored and an optimum condition for the PANI thin film preparation was established. The resulting PANI film was characterized with UV–visible spectrophotometer, FTIR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The PANI thin film possessed nanofibers with a diameter ranging from 15 to 20 nm. The NO2 gas sensing behavior was studied by measuring the change in electrical conductivity of PANI film with respect to NO2 gas concentration and exposure time. The optimized sensor exhibited a sensitivity factor of 206 with a response time of 23 sec. The NO2 gas sensor using nanofibrous PANI thin film as sensing probe showed a linear current response to the NO2 gas concentration in the range of 10–100 ppm. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
62.
Quantitative Structure-Activity Relationship modeling is a powerful approach for correlating an organic compound to its lipophilicity.
In this paper QSAR models are established for estimation of correlation of the lipophilicity of a series of pyrrolyl-acetic
acid derivatives, inhibitors of the aldose reductase enzyme, in the n-octanol-water system with biological activity of aldose reductase. Lipophilicity, expressed by the logarithm of n-octnol-water partition coefficient log P and biological activity of aldose reductase inhibitory activity by log it. Result obtained by QSAR modeling of compound series
reveal a definite trend in biological activity and a further improvement in quantitative relationships are established if,
beside log P, Hammett electronic constant σ and connectivity index chi-3 (3
χ) term included in the regression equation. 相似文献
63.
P. Sumati Kumari 《Journal of the Egyptian Mathematical Society》2013,21(3):276-280
This paper proves the existence of periodic and fixed points for contractive conditions in metric (symmetric) space. 相似文献
64.
Amit Kumar Gupta Kumkum Kumari Neetu Singh Dushyant Singh Raghuvanshi Krishna Nand Singh 《Tetrahedron letters》2012,53(6):650-653
An environmentally benign, ionic liquid promoted multicomponent protocol to benzopyrano(2,3-d)pyrimidines and 4H-chromenes has been developed at room temperature. Results of the reaction depend on the nature of the nucleophile used in the reaction. Secondary amines result in the formation of benzopyrano(2,3-d)pyrimidines, whereas thiols give rise to 4H-chromenes under the same set of reaction conditions. 相似文献
65.
S.K. Das Amrita Kumari D. Bandopadhay S.A. Akbar G.K. Mondal 《Applied Mathematical Modelling》2011,35(9):4208-4221
A first principle based mathematical model has been developed to characterise the effect of total liquid hold-up on the bosh silicon distribution behaviour in the dripping zone of a blast furnace. Two specific cases of hold-up behaviour have been investigated, namely, hold-up in the absence and in the presence of counter current gas flow conditions. The model exemplifies coupled phenomenon of chemical kinetics, transport processes and liquid hold-up to characterise the silicon behaviour in the dripping zone. The present modelling investigation shows that the bosh silicon level diminishes with the enhanced liquid hold-up in the dripping zone. Further, the influence of counter current gas flow on the hold-up is not significant. However, it has been observed that the liquid phase temperature reduces with increased liquid hold-up in dripping zone under steady state operating conditions. The model predictions of bosh silicon distribution have been validated with the published literatures (bulk values) and found to be in good agreement. 相似文献
66.
The reactions of dimeric complex [Rh(CO)2Cl]2 with hemilabile ether‐phosphine ligands Ph2P(CH2) nOR [n = 1, R = CH3 (a); n = 2, R = C2H5 (b)] yield cis‐[Rh(CO)2Cl(P ~ O)] (1) [P ~ O = η 1‐(P) coordinated]. Halide abstraction reactions of 1 with AgClO4 produce cis‐[Rh(CO)2(P ∩ O)]ClO4 (2) [P ∩ O = η 2‐(P,O)chelated]. Oxidative addition reactions of 1 with CH3I and I2 give rhodium(III) complexes [Rh(CO)(COCH3)ClI(P ∩ O)] (3) and [Rh(CO)ClI2(P ∩ O)] (4) respectively. The complexes have been characterized by elemental analyses, IR, 1H, 13C and 31P NMR spectroscopy. The catalytic activity of 1 for carbonylation of methanol is higher than that of the well‐known [Rh(CO)2I2]? species. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
67.
The combined effects of the permeability of the medium, magnetic field, buoyancy forces and dissipation on the unsteady mixed convection flow over a horizontal cylinder and a sphere embedded in a porous medium have been studied. The nonlinear coupled partial differential equations with three independent variables have been solved numerically using an implicit finite-difference scheme in combination with the quasilinearization technique. The skin friction, heat transfer and mass transfer increase with the permeability of the medium, magnetic field and buoyancy parameter. The heat and mass transfer continuously decrease with the stream-wise distance, whereas the skin friction increases from zero, attains a maximum and then decreases to zero. The skin friction, heat transfer and mass transfer are significantly affected by the free stream velocity distribution. The effect of dissipation parameter is found to be more pronounced on the heat transfer than on the skin friction and mass transfer.Untersucht wurden kombinierte Effekte der Permeabilität des Mediums, des magnetischen Feldes, der Auftriebskräfte und der Dissipation auf die instationäre Mischkonvektions-Strömung über einen horizontalen Zylinder und eine Kugel, die in einem porösen Medium eingebettet sind. Die nichtlinearen gekoppelten partiellen Differentialgleichungen mit drei unabhängigen Variablen wurden numerisch unter Benutzung eines impliziten Finite-Differenzen-Verfahrens in Verbindung mit der Quasi-Linearisierungstechnik gelöst. Die Oberflächenreibung und die Wärme- und Stoffübertragung steigen mit der Permeabilität des Mediums, dem magnetischen Feld und dem Auftriebsparameter an. Die Wärme- und Stoffübertragung fällt stetig in Strömungsrichtung ab, wohingegen die Oberflächenreibung von Null ansteigt, ein Maximum erreicht und wieder auf Null abfällt. Die Oberflächenreibung und die Wärme- und Stoffübertragung werden signifikant von der Verteilung der Freistromgeschwindigkeit beeinflut. Es wurde festgestellt, das der Dissipations-Parameter stärker die Wärmeübertragung als die Oberflächenreibung und die Stoffübertragung beeinflut. 相似文献
68.
Gayatri Kumari N. R. Patil Venkata Srinu Bhadram Ritesh Haldar Satyanarayana Bonakala Tapas Kumar Maji Chandrabhas Narayana 《Journal of Raman spectroscopy : JRS》2016,47(2):149-155
Interpenetrating metal organic frameworks are interesting functional materials exhibiting exceptional framework properties. Uptake or exclusion of guest molecules can induce sliding in the framework making it porous or non‐porous. To understand this dynamic nature and how framework interaction changes during sliding, metal organic framework (MOF) 508 {Zn(BDC)( 4,4′‐Bipy)0.5 · DMF(H2O)0.5} was selected for study. We have investigated structural transformation in MOF‐508 under variable conditions of temperature, pressure and gas loading using Raman spectroscopy and substantiated it with IR studies and density functional theory (DFT) calculations. Conformational changes in the organic linkers leading to the sliding of the framework result in changes in Raman spectra. These changes in the organic linkers are measured as a function of high pressure and low temperature, suggesting that the dynamism in MOF‐508 framework is driven by ligand conformation change and inter‐linker interactions. The presence of Raman signatures of adsorbed CO2 and its librational mode at 149 cm−1 suggests cooperative adsorption of CO2 in the MOF‐508 framework, which is also confirmed from DFT calculations that give a binding energy of 34 kJ/mol. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
69.
Kalawati Meena Sudesh Kumari Jitender M. Khurana Amita Malik Chetan Sharma Harsh Panwar 《中国化学快报》2017,28(1):136-142
A simple and efficient three component procedure has been developed for the synthesis of highly substituted spiro[indolo-3,10'-indeno[1,2-b]quinolin]-2,4,11'-triones by one pot three component condensation of enaminones, isatin and indane-1,3-dione in ethanol:water (1:1) in presence of ceric ammonium nitrate (CAN) as catalyst. This method provides several advantages such as lesser reaction time, high yield of products and operational simplicity. The antimicrobial activity of some of the compounds has been investigated against six microbial strains, some of the tested compounds showed good antimicrobial activity. 相似文献
70.
Sagar Suman Panda Khusbu Sharma Bijeta Mohanty Ravi Kumar Venkata Varaha Bera Sasmita Kumari Acharjya Sarwar Beg 《液相色谱法及相关技术杂志》2017,40(19):951-958
An ultrafast liquid chromatographic bioanalytical method was developed and validated for the determination of telaprevir in Wistar albino rat serum. Principles of quality by design (QbD) were implemented for enhancing the bioanalytical liquid–liquid extraction of telaprevir from rat serum. A Box–Behnken design was utilized in the studies by selecting extraction time, centrifugation speed, and vortex time as the critical method variables for evaluating their effect on the critical analytical attribute, i.e., %recovery of telaprevir. Chromatographic separation was achieved within a run time of 10?min using a C-18 column and mobile phase comprising of methanol:borate buffer of pH 9 (90:10 v/v) flowing at 1.2?mL/min. Photodiode array detection was performed at 270?nm. Results of validation studies were satisfactory. The method was linear over a concentration of 25–10,000?ng/mL. Limit of detection for the developed method was 10?ng/mL. Further, design of experiments (DoE) used for inter-day accuracy and precision study suggested superior method reliability. This integrated QbD- and DoE-based approach ensured the development of a validated and reliable analytical method for optimum bioanalysis of telaprevir in biological matrix. 相似文献