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1.
Summary The liquid phase oxidation of gold in donor-acceptor organic and aqueous-organic media has been studied. The compounds [AuCl(Me2S)], [AuBr(Me2S)], [AuBr3(Me2S)], [Me3S][AuBr4], [Me3S][AuBr4(Me2S)]·H2O, [Me3SO]-[AuBr4]·H2O, [Me3S][Au2Br7(Me2S)2]·3H2O, [Me3S]2-[Au2Br8]·2DMSO·H2O, [Me2(Bu)SO][AuBr4]·H2O and [Me3S]Br were isolated by dissolution of Au0 in DMSO-RX mixtures (R = H or Bu; X = Cl or Br). The products were characterized by elemental analysis and i.r. spectroscopy. The nature of the Au0-DMSO-RX systems and the oxidant species are discussed in terms of a newly-developed concept of donor-acceptor electron transport (DAET) systems. 相似文献
2.
A. A. Lavrentiev B. V. Gabrel’yan I. Ya. Nikiforov 《Journal of Structural Chemistry》1998,39(6):884-889
The electronic energy structure of substitution solid solutions CuGa(SxSe1−x)2 is studied within wide limits of sulfur concentration x in the onion sublattice. The SK absorption spectrum is calculated
for CuGaS2 in a high-order multiple scattering approximation using the FEFF7 program. For all concentrations x, partial densities of
states are calculated in a full multiple scattering approximation by the local coherent potential method. The calculation
schemes for the filled and vacant states are employed, which differ in a choice of the crystalline potential. The effect of
a vacancy on the SK level on the density of the free Sp states is considered. The theoretical K absorption spectra and densities
of states of CuGaS2 are compared with the experimental X-ray and X-ray photoelectron spectra. The calculated curves are in good agreement with
the experiment. It is established that the densities of the S and Se p states change smoothly with varying concentration of
anions.
Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 6, pp. 1076–1082, November–December, 1998. 相似文献
3.
Alexander V. Avdeev Eldar V. Goriounov Mikhail M. Lavrentiev Jr. Renato Spigler 《Applied Mathematical Modelling》2009
A behavior-oriented diffusion model, governing the time evolution of the cross-shore position of coastal profiles, is studied. Here, two time-independent, space-varying coefficients, which embody the relevant physical properties, are identified simultaneously. Two sets of real data, the first measured over 10 years at Duck, in NC (USA), the second obtained over 39 years measurements at Delfland (Holland), have been processed numerically by a suitable “inversion algorithm”, earlier developed by the authors. This is based on the minimization of a certain cost functional in order to identify both coefficients. The numerical results, obtained by solving the diffusion equation with the so-determined coefficients, favorably agree with the real data, which fact validates and calibrates somehow the diffusion model under investigation. A short-term prediction is finally obtained for coastal profiles, using such a model. 相似文献
4.
We consider the degenerate elliptic operator acting on ${C^2_b}$ functions on [0,∞) d : $$\mathcal{L}f(x)=\sum_{i=1}^d a_i(x) x_i^{\alpha_i} \frac{\partial^2 f}{\partial x_i^2} (x) +\sum_{i=1}^d b_i(x) \frac{\partial f}{\partial x_i}(x), $$ where the a i are continuous functions that are bounded above and below by positive constants, the b i are bounded and measurable, and the ${\alpha_i\in (0,1)}$ . We impose Neumann boundary conditions on the boundary of [0,∞) d . There will not be uniqueness for the submartingale problem corresponding to ${\mathcal{L}}$ . If we consider, however, only those solutions to the submartingale problem for which the process spends 0 time on the boundary, then existence and uniqueness for the submartingale problem for ${\mathcal{L}}$ holds within this class. Our result is equivalent to establishing weak uniqueness for the system of stochastic differential equations $$ {\rm d}X_t^i=\sqrt{2a_i(X_t)} (X_t^i)^{\alpha_i/2}{\rm d}W^i_t + b_i(X_t) {\rm d}t + {\rm d}L_t^{X^i},\quad X^i_t \geq 0, $$ where ${W_t^i}$ are independent Brownian motions and ${L^{X_i}_t}$ is a local time at 0 for X i . 相似文献
5.
MY Lavrentiev K Mergia M Gjoka D Nguyen-Manh G Apostolopoulos SL Dudarev 《J Phys Condens Matter》2012,24(32):326001, 1-326001, 5
We present a combined experimental and computational study of high temperature magnetic properties of Fe-Cr alloys with chromium content up to about 20?at.%. The magnetic cluster expansion method is applied to model the magnetic properties of random Fe-Cr alloys, and in particular the Curie transition temperature, as a function of alloy composition. We find that at low (3-6?at.%) Cr content the Curie temperature increases with the increase of Cr concentration. It is maximum at approximately 6?at.% Cr and then decreases for higher Cr content. The same feature is found in thermo-magnetic measurements performed on model Fe-Cr alloys, where a 5?at.% Cr alloy has a higher Curie temperature than pure Fe. The Curie temperatures of 10 and 15?at.% Cr alloys are found to be lower than the Curie temperature of pure Fe. 相似文献
6.
A.N. Andreyev D. Ackermann P. Cagarda J. Gerl F.P. Heßberger S. Hofmann M. Huyse A. Keenan H. Kettunen A. Kleinböhl A. Lavrentiev M. Leino B. Lommel M. Matos G. Münzenberg C.J. Moore C.D. O'Leary R.D. Page S. Reshitko S. Saro C. Schlegel H. Schaffner M.J. Taylor P. Van Duppen L. Weissman R. Wyss 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):129-133
The 137I nucleus, populated in the spontaneous fission of 248Cm has been studied by means of prompt γ-ray spectroscopy using the EUROGAM2 array. Medium-spin yrast excitations in 137I were observed for the first time. The experimental level scheme is compared to the shell model calculation with modified
Kuo-Herling interaction. The theoretical predictions differ significantly from the experimental results, indicating that the
excitation pattern in 137I deviates significantly from the shell model scheme.
Received: 6 June 2001 / Accepted: 4 October 2001 相似文献
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8.
V. R. Belosludov M. Yu. Lavrentiev Yu. A. Dyadin S. A. Syskin 《Journal of inclusion phenomena and macrocyclic chemistry》1990,8(1-2):59-69
Vibrational spectra and thermodynamic properties of ices and the cubic structure I (CS-I) clathrate hydrate have been studied by the lattice dynamics method. The phonon density of states for the empty hydrate framework and for xenon hydrate have been determined; the vibrational frequencies of the guest molecules in large and small cavities have been found. The stability of the hydrate with respect to the external pressure at low temperatures and its thermodynamic stability at temperatures around 0°C have been studied. It has been found that the empty hydrate framework is unstable in certain temperature and pressure regions. A definite degree of occupation of the large cavities by the guest molecules is necessary for the hydrate to become stable. It has been found that there is a maximum of the critical temperature at which the hydrate exists, which is a function of the external pressure.Dedicated to Dr. W. Davidson in honor of his great contributions to the sciences of inclusion phenomena. 相似文献
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10.
Igor P. Lavrentiev Lidia G. Korableva Elena A. Lavrentieva Galina A. Nifontova Mikhail L. Khidekel Irina G. Gusakovskaya Tatiana I. Larkina Levon D. Arutyunian Olga S. Filipenko Vasiliy I. Ponomarev L. O. Atovmyan 《Transition Metal Chemistry》1980,5(1):193-200
Summary Direct oxidation of iron and copper in a donor-acceptor medium, L + CCl4, where L is dimethylsulphoxide, dimethylformamide or acetonitrile was employed to obtain complex compounds:cis-[FeCl2(DMSO)4]Cl] (3), 2 FeCl3 · 3 DMSO (5), [FeCl(DMSO)5][FeCl4]2] (6), [FeCl(DMSO)5][Fe2Cl6O] (7),cis-[FeCl2(DMF)4][FeCl4] (8), [Fe(MeCN)6][FeCl4]2 (9) andcis-[CuCl2(DMF)2]2 (10), The structures of complexes (9) and (10) have been established by x-ray diffraction analysis and compared with those of (3), (6), (7) and (8) which are reported elsewhere.The [FeCl(DMSO)5][Fe2Cl6O] complex (7) is formed by oxidation of iron fromcis-[FeIIICl2(DMSO)4]2[FeIICl4] (4) in ethanol. One of the 5 DMSO molecules of (7) was found to be disordered; the Mössbauer spectroscopy data suggest that it can move within the cation coordination sphere.Mössbauer spectroscopy and x-ray diffraction analysis indicate electron isomerism in one of the complexes.For papers 4 and 5 of these series see refs. 1 and 2. 相似文献