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排序方式: 共有480条查询结果,搜索用时 15 毫秒
91.
Kaushik Bhattacharya Anja Schlömerkemper 《Archive for Rational Mechanics and Analysis》2010,196(3):715-751
Shape-memory alloys undergo a solid-to-solid phase transformation involving a change of crystal structure. We examine model
problems in the scalar setting motivated by the situation when this transformation is induced by the application of stress
in a polycrystalline material made of numerous grains of the same crystalline solid with varying orientations. We show that
the onset of transformation in a granular polycrystal with homogeneous elasticity is in fact predicted accurately by the so-called
Sachs bound based on the ansatz of uniform stress. We also present a simple example where the onset of phase transformation
is given by the Sachs bound, and the extent of phase transformation is given by the constant strain Taylor bound. Finally
we discuss the stress–strain relations of the general problem using Milton–Serkov bounds. 相似文献
92.
Kaushik Mallick Mike J. Witcomb Andy Dinsmore Mike S. Scurrell 《Macromolecular rapid communications》2005,26(4):232-235
Summary: We report a new method for the preparation of polyaniline nanoballs by using HAuCl4 as an oxidizing agent. During the reaction, aniline is oxidized and forms polyaniline whilst the hydrogen tetrachloroaurate is reduced and forms gold nanoparticles. These gold nanoparticles are found to decorate the nanoballs.
93.
Ovender Singh Priyanka Gupta Anshu Singh Ankur Maji Udai P. Singh Kaushik Ghosh 《应用有机金属化学》2019,33(5)
Hexacoordinated non‐heme iron complexes [FeII(L1)2](ClO4)2 ( 1 ) and [FeII(L2)2](PF6)2 ( 2 ) have been synthesized using ligands L1 = (E)‐2‐chloro‐6‐(2‐(pyridin‐2ylmethylene) hydrazinyl)pyridine and L2 = (E)‐2‐chloro‐6‐(2‐(1‐(pyridin‐2‐yl)ethylidene)hydrazinyl) pyridine]. These complexes are highly active non‐heme iron catalysts to catalyze the C (sp3)?H bonds of alkanes. These iron complexes have been characterized using ESI?MS analysis and molecular structures were determined by X‐ray crystallography. ESI ? MS analysis also helped to understand the generation of intermediate species like FeIII?OOH and FeIV=O. DFT and TD?DFT calculations revealed that the oxidation reactions were performed through high‐valent iron center and a probable reaction mechanism was proposed. These complexes were also utilized for the degradation of orange II and methylene blue dyes. 相似文献
94.
Sachin B. Pandya Urmila H. Patel Kaushik P. Chaudhary Bhavesh N. Socha Nikita J. Patel Bhupesh S. Bhatt 《应用有机金属化学》2019,33(12)
Novel cobalt complex of 4‐amino‐N‐(6‐chloropyridazin‐3‐yl)benzene sulfonamide (sulfachloropyridazine) has been synthesized and characterized by elemental analysis, FT‐IR spectroscopy and magnetic susceptibility (VSM). Cobalt complex of Sulfachloropyridazine (Co‐SCP) crystallized in monoclinic space group P21/n with Z = 4. The structure is solved by direct method and refined to R = 0.099 for 4720 reflections with I ?4σ(I). The results of FT‐IR spectra suggest the binding of cobalt atom to the sulfonamide ligand which is in agreement with the crystal structure determination. In crystal structure, molecule is linked via, C‐H … π, C‐Cl … π and π … π intermolecular interactions. The computational studies like the optimization energy and root means square deviation compare with single crystal structure, frontier molecular orbital (Homo‐Lumo energy) and binding energy of the Co‐SCP has been carried out using DFT/B3LYP level of theory in gaseous phase. Hirshfeld surfaces and the 2D‐fingerprint analysis are performed to study the nature of interactions and their measurable contributions towards crystal packing. The interaction of the complex with DNA is investigated using viscosity measurement and absorption titration studies. The result shows the complex bind to DNA with intercalative mode with high DNA‐binding constant (Kb). Also, in vivo and in vitro cytotoxic studies are performed using S. pombe cells and brine shrimp lethality bioassay. DNA‐cleavage study shows better cleaving ability of the complex. 相似文献
95.
A series of (C9H7)2Zr(OAr)Cl and (C9H7)2Zr(OAr)2 complexes, where Ar = C6H5, p-ClC6H4, α-C10H7, or β-C10H7, have been synthesised by the reaction of bis(indenyl)zirconium(IV)-dichloride with an appropriate phenol in a 1:1 and 1:2 molar ratio in refluxing benzene in the presence of triethylamine. These complexes have been characterised by elemental analyses, conductance measurements and spectral (IR, 1H NMR and electronic) studies. 相似文献
96.
97.
We propose a variant of the time-dependent multi-configuration Hartree method within the framework of Fourier grid Hamiltonian
method. The workability of the method proposed is demonstrated with a well-known coupled two-mode problem. 相似文献
98.
The kinetics of isothermal decomposition of solid K2Zr2(O2)2F6·2H2O have been studied in the temperature range 100–226° under vacuum. The fractional decomposition has been determined by measuring the pressure of evolved oxygen during pyrolysis with the help of a McLeod gauge. The values ranged from 0.05 to 0.62. The vs. t data showed that the kinetics are deceleratory throughout the course of the reaction. The initial part of the decomposition reaction could be best described by a unimolecular decay law, while the later stages obey contracting volume kinetics. The activation energies have been determined and the respective values for the above stages are 13.6 and 6.9 kcal·mole–1.
One of the authors (SMK) is grateful to I.I.T. Delhi for a research scholarship. 相似文献
Zusammenfassung Die Kinetik der isothermen Zersetzung von festen K2Zr2(O2)2F6·2H2O wurde im Temperaturbereich von 100–226° im Vakuum untersucht. Die fraktionierte Zersetzung wurde durch Messung des Druckes des während der Pyrolyse entwickelten Sauerstoffs mit einem McLeod-Manometer bestimmt. Die -Werte variierten von 0.05 bis 0.62. Die -t Daten zeigen, daß die Kinetik im Verlauf der Reaktion herabgesetzt wird. Der erste Teil der Zersetzungsreaktion konnte am besten durch ein unimolekulares Zerfallgesetzt beschrieben werden, während die späteren Phasen der Kinetik der Volumenkontraktion gehorchten. Die Aktivierungsenergien wurden berechnet und die entsprechenden Werte für obige Reaktionen ergaben sich 13.6 bzw. 6.9 Kcal mol–1.
K2Zr2(O2)2F6·22 100–226°. «» , , . «» 0.05 0.62. –t , . , — . , , , 13.6 6.9 .–1.
One of the authors (SMK) is grateful to I.I.T. Delhi for a research scholarship. 相似文献
99.
Summary Ionic chelate complexes of the type, [(5-R)2ML][dtz] [R=cyclopentadienyl (Cp) or indenyl (C9H7); M=TiIV, ZrIV or HfIV; HL=oxine; dtz=phenyldithiocarbazate (PhNHNHCS2)] have been synthesised and characterised. Conductance measurements indicate that the complexes are 11 electrolytes. From i.r. and u.v. spectral studies we conclude that the oxinato-group is chelating. Consequently there is tetrahedral coordination around the metal ion.1H and13C N.m.r. studies are consistent with the stoichiometries. X-ray powder diffraction studies have been made for [(5-Cp)2ZrL][dtz]. For [(5-Cp)2TiL][dtz] and [(5-Cp)2ZrL][dtz] thermal (t.g. and d.t.a.) and mass spectral studies have been carried out. 相似文献
100.
A. K. Sharma B. Khera N. K. Kaushik 《Monatshefte für Chemie / Chemical Monthly》1983,114(8-9):907-913
A series of (C9H7)2Zr(SB)Cl complexes whereSB
– is the anion of bidentateSchiff base derived from salicylaldehyde and 4-substituted anilines, viz. salicylidene-4-ansidine, salicylidene-4-phenetidine, salicylidene-4-chloroaniline, salicylidene-4-bromoaniline, salicylidene-4-iodoaniline and salicylidene-4-nitroaniline, have been synthesized by the reaction of bis(indenyl)zirconium(IV) dichloride andSchiff base (SBH) in 1:1 molar ratio in refluxingTHF in the presence of triethylamine. The new derivatives have been characterized on the basis of their elemental analyses, conductance measurements and spectral (IR,1H-NMR, UV-VIS) studies.
Bis(indenyl)zirkonium(IV)-Komplexe monofunktioneller zweizähniger Salicylidimine
Zusammenfassung Es wurde eine Reihe von (C9H7)2Zr(SB)Cl-Komplexen synthetisiert, wobeiSB – für das Anion einer zweizähnigenSchiff-Base steht. DieSchiff-Basen sind von Salicylaldehyd und 4-substituierten Anilinen hergeleitet: Salicyliden-4-anisidin,-4-phenetidin, -4-Cl-, -4-Br-, -4-I-anilin und -4-Nitroanilin. Die Synthese erfolgte über die Reaktion von Bis(indenyl)zirkonium(IV)-dichlorid mit derSchiff-Base (SBH) in einem molaren Verhältnis von 1:1 am Rückfluß in Gegenwart von Triethylamin undTHF als Lösungsmittel. Zur Charakterisierung der neuen Derivate wurden Elementaranalysen, Leitfähigkeitsmessungen und spektroskopische Daten (IR,1H-NMR, UV-VIS) herangezogen.相似文献