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131.
Alexander V. Zuraev Yuri V. Grigoriev Vladislav A. Budevich Oleg A. Ivashkevich 《Tetrahedron letters》2018,59(16):1583-1586
A new method for Huisgen [3+2] cycloaddition synthesis of 1,4- and 1,4,5-substituted-1H-1,2,3-triazoles was reported. The reaction was catalyzed by the product of thermolysis of copper (II) poly-5-vinyltetrazolate. Heterogeneous catalyst includes copper nanoparticles which supported on polymeric matrix. It presents recovered and recycled catalyst and the catalyzed reaction proceeds in aerobic conditions at room temperature in aqueous media. 相似文献
132.
Vladislav N. Kovalnogov Ruslan V. Fedorov Viktor M. Golovanov Boris M. Kostishko T. E. Simos 《Journal of mathematical chemistry》2018,56(1):81-102
In this paper we obtain, for the first time in the literature a new numerical pair. The properties of the new pair are: For this new numerical pair we present a detailed theoretical analysis. Finally, we prove the efficiency of the new scheme by applying it to the solution of systems of coupled Schrödinger equations.
相似文献
- 1.symmetric two-step algorithm,
- 2.four-stages scheme,
- 3.scheme of tenth-algebraic order,
- 4.the approximations of the layers are taken place as follows: first and second layer on the point \(x_{n-1}\), third layer on the point \(x_{n}\), fourth layer on the point \(x_{n+1}\),
- 5.the method has eliminated the phase-lag and its first derivative,
- 6.excellent stability and interval of periodicity properties (i.e. interval of periodicity equal to \(\left( 0, \infty \right) \).
133.
134.
Vladislav Čápek 《Czechoslovak Journal of Physics》1996,46(11):1001-1009
We apply a previous analysis of the dependence of the dynamic time-convolution equations and their solution on the degree of the initial strength of the polaron cloud to the usual zero-bias spin-boson model and standard second order (i.e. Born) approximation (in tunneling, i.e. the standard dilute blip approximation at =1). At temperatureT=0 and for the usual Ohmic type spin-boson coupling, the asymptotic-time-symmetry-breaking phenomenon as a function of the coupling strentghg can be analyzed, in the above Born approximation, in the wholeg- plane. A hardly interpretable conclusion is found that the symmetry breaking in the above approximation appears just at discrete lines in the plane. This implies instability of the phenomenon in the second-order theory with respect to arbitrarily small perturbations of the initial state and complies with exact proofs of absence of the partial symmetry-breaking phenomenon in analogous symmetric models.The author has pleasure in acknowledging fruitful discussions with Dr. P. Chvosta and Prof. M. Wagner. Supports of grants 292/1994 from the Grant agency of Charles University and 202/93/2428 from the Czech Grant Agency are also gratefully acknowledged. 相似文献
135.
Adam R. Hill Pablo Cubillas James T. Gebbie-Rayet Mollie Trueman Nathan de Bruyn Zulaikha al Harthi Rachel J. S. Pooley Martin P. Attfield Vladislav A. Blatov Davide M. Proserpio Julian D. Gale Duncan Akporiaye Bjrnar Arstad Michael W. Anderson 《Chemical science》2021,12(3):1126
A Monte Carlo crystal growth simulation tool, CrystalGrower, is described which is able to simultaneously model both the crystal habit and nanoscopic surface topography of any crystal structure under conditions of variable supersaturation or at equilibrium. This tool has been developed in order to permit the rapid simulation of crystal surface maps generated by scanning probe microscopies in combination with overall crystal habit. As the simulation is based upon a coarse graining at the nanoscopic level features such as crystal rounding at low supersaturation or undersaturation conditions are also faithfully reproduced. CrystalGrower permits the incorporation of screw dislocations with arbitrary Burgers vectors and also the investigation of internal point defects in crystals. The effect of growth modifiers can be addressed by selective poisoning of specific growth sites. The tool is designed for those interested in understanding and controlling the outcome of crystal growth through a deeper comprehension of the key controlling experimental parameters.Generic in silico methodology – CrystalGrower – for simulating crystal habit and nanoscopic surface topology to determine crystallisation free energies. 相似文献
136.
Vladislav A. Sadykov Nikita F. Eremeev Ekaterina M. Sadovskaya Anna V. Shlyakhtina Elena Yu Pikalova Denis A. Osinkin Aleksey A. Yaremchenko 《Current Opinion in Green and Sustainable Chemistry》2022
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137.
Jong-San Chang Do-Young Hong Vladislav P. Vislovskiy Sang-Eon Park 《Catalysis Surveys from Asia》2007,11(1-2):59-69
Utilization of carbon dioxide as a soft oxidant for the catalytic dehydrogenation of ethylbenzene (CO2-EBDH) has been recently attempted to explore a new technology for producing styrene selectively. This article summarizes
the results of our recent attempts to develop effective catalyst systems for the CO2-EBDH on the basis of alumina-supported vanadium oxide catalysts. Its initial activity and on-stream stability were essentially
improved by the introduction of antimony oxide as a promoter into the alumina-supported catalyst. Insertion of zirconium oxide
into alumina support substantially increased the catalytic activity. Modification of alumina with magnesium oxide yielded
an increase of catalyst stability of alumina-supported V–Sb oxide due to the coking suppression. Carbon dioxide has been confirmed
to play a beneficial role of selective oxidant in improving the catalytic performance through the oxidative pathway, avoiding
excessive reduction and maintaining desirable oxidation state of vanadium ion (V5+). The positive effect of carbon dioxide in dehydrogenation reactions of several alkylbenzenes such as 4-diethylbenzene, 4-ethyltoluene,
and iso- and n-propylbenzenes was also observed. Along with the easier redox cycle between fully oxidized and partially reduced vanadium
species, the optimal surface acidity of the catalyst is also responsible for achieving high activity and catalyst stability.
It is highlighted that supra-equilibrium EBDH conversions were obtained over alumina-supported V–Sb oxide catalyst in CO2-EBDH as compared with those in steam-EBDH in the absence of carbon dioxide. 相似文献
138.
Karel Pomeisl Jaroslav Kví?ala Antonín Klásek Vladislav Kubelka Jan ?ejka 《Tetrahedron》2007,63(42):10549-10561
3-(Fluoroacyloxy)quinoline-2,4(1H,3H)-diones react with triethyl phosphite to afford either the product of the Perkow reaction or the corresponding 4-ethoxyquinolin-2(1H)-one. In both reactions, the fluorocarboxylate anion acts as the leaving group. For the corresponding 3-(fluoroiodoacetoxy) derivative this observation precludes the application of the intramolecular Wittig-Horner synthesis to modify quinoline-2,4(1H,3H)-diones by the annulation of a fluorinated but-2-enolide moiety. 相似文献
139.
Wall coating for capillary electrophoresis on microchips 总被引:2,自引:0,他引:2
Dolník V 《Electrophoresis》2004,25(21-22):3589-3601
This review article with 116 references describes recent developments in the preparation of wall coatings for capillary electrophoresis (CE) on a microchip. It deals with both dynamic and permanent coatings and concentrates on the most frequently used microchip materials including glass, poly(methyl methacrylate), poly(dimethyl siloxane), polycarbonate, and poly(ethylene terephthalate glycol). Characterization of the channel surface by measuring electroosmotic mobility and water contact angle of the surface is included as well. The utility of the microchips with coated channels is demonstrated by examples of CE separations on these chips. 相似文献
140.
The [Fe(II)(Cys)(4)](2-) site of rubredoxin from Clostridium pasteurianum (Rd(red)) has been studied by M?ssbauer spectroscopy in both purified protein and whole cells of Escherichia coli overproducing it. Excellent fits were obtained to an S = 2 spin Hamiltonian for D = 5.7(3) cm(-1), E/D = 0.25(2), delta = 0.70(3) mm/s, DeltaE(Q) = -3.25(2) mm/s, eta = 0.75(5), A(x) = -20.1(7) MHz, A(y) = -11.3(2) MHz, and A(z) = -33.4(14) MHz. These parameters were analyzed with crystal-field theory for the (5)D manifold of iron(II), revealing a d(z(2)) orbital ground state that is admixed by approximately 0.21 d(x(2) - y(2)). The spin-Hamiltonian parameters are consistent within the (5)D theory, apart from the zero-field splitting parameter, D. This problem was solved by extending the crystal-field treatment with spin-orbit coupling to spin-triplet d-d excited states of the iron. Theoretical estimates are given for the spin-triplet (D(T)) and spin-quintet contributions (D(Q)) to D based on excitation energies derived from time-dependent density functional theory, TD-DFT. The computational results were interpreted in terms of crystal-field theory, yielding the Racah parameters B = 682 cm(-1) and C = 2583 cm(-1). The theoretical analysis gives the relative magnitudes D(Q):D(T):D(ss) = 51%: 42%:7% (D(ss) originates from spin-spin interaction). The DFT analysis corroborates the pivotal role of the torsion angles (omega(i)) of the C-S(i) bonds in shaping the electronic structure of the iron(II) site. Rd(red) in overexpressing whole cells accounts for 60% of the M?ssbauer absorption. The Rd(red) spectra from whole cells are virtually identical to those of the purified protein. By using the theoretical omega dependence of the spin Hamiltonian parameters, the torsions for Rd(red) in whole cells and purified protein samples are estimated to be the same within 2 degrees. These findings establish M?ssbauer spectroscopy as a structural tool for investigating iron sites in whole cells. 相似文献