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排序方式: 共有804条查询结果,搜索用时 343 毫秒
61.
A. L. Lapidus O. L. Eliseev M. V. Tsapkina P. E. Davydov O. S. Belousova 《Kinetics and Catalysis》2010,51(5):731-735
The dependence of the properties of supported cobalt catalysts for hydrocarbon synthesis from CO and H2 on the porous structure of the supports (aluminas and aluminosilicates) is reported. A correlation between the mean Co0 crystallite size and the pore diameter of the support is established. The specific CO conversion rate falls sharply as the
size of Co0 particles decreases to 6 nm and below. The methane and C5+ hydrocarbon selectivities as a function of the Co0 crystallite size pass through an extremum. 相似文献
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63.
M. M. Savel'ev A. L. Lapidus I. B. Kolesnikova N. Ya. Usachev Kh. M. Minachev O. N. Usacheva 《Russian Chemical Bulletin》1992,41(9):1722-1722
N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2195–2196, September, 1992. 相似文献
64.
A. L. Lapidus A. Yu. Krylova B. V. Kuklin A. Zukal J. Rathouský J. Stárek 《Russian Chemical Bulletin》1995,44(6):1031-1034
Catalysts prepared by mechanical mixing of high-silica zeolite ZSM-5 with cobalt oxide Co3O4, basic cobaltous carbonate, and cobaltous carbonate were studied. The nature of the cobalt compound introduced into the mixture affects the catalytic and physicochemical properties of the catalyst. The presence of Co3O4 in the sample (introduced as oxide or obtained by thermal decomposition of the carbonate) is favorable to the formation of aromatic compounds from CO and H2. The use of cobaltous carbonates for the preparation of catalysts results in development of the porous structure of the catalyst. During preparation of samples, the mechanical treatment partially destroys the zeolite framework of the support.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1070–1073, June, 1995. 相似文献
65.
Zacher D Yusenko K Bétard A Henke S Molon M Ladnorg T Shekhah O Schüpbach B de los Arcos T Krasnopolski M Meilikhov M Winter J Terfort A Wöll C Fischer RA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(5):1448-1455
The progressive liquid-phase layer-by-layer (LbL) growth of anisotropic multicomponent layer-based porous coordination polymers (PCPs) of the general formula [M(L)(P)(0.5)] (M: Cu(2+), Zn(2+); L: dicarboxylate linker; P: dinitrogen pillar ligand) was investigated by using either pyridyl- or carboxyl-terminated self-assembled monolayers (SAMs) on gold substrates as templates. It was found that the deposition of smooth, highly crystalline, and oriented multilayer films of these PCPs depends on the conditions at the early growth cycles. In the case of a two-step process with an equimolar mixture of L and P, growth along the [001] direction is strongly preferred. However, employing a three-step scheme with full separation of all components allows deposition along the [100] direction on carboxyl-terminated SAMs. Interestingly, the growth of additional layers on top of previously grown oriented seeding layers proved to be insensitive to the particular growth scheme and full retention of the initial orientation, either along the [001] or [100] direction, was observed. This homo- and heteroepitaxial LbL growth allows full control over the orientation and the layer sequence, including introduction of functionalized linkers and pillars. 相似文献
66.
67.
Olson C Heth CL Lapidus SH Stephens PW Halder GJ Pokhodnya K 《The Journal of chemical physics》2011,135(2):024503
The M-[TCNE] (M = 3d metal; TCNE = tetracyanoethylene) system is one of the most interesting classes of molecule-based magnets, exhibiting a plethora of compositions and structures (inorganic polymer chains, 2D layers, 3D networks, and amorphous solids) with a wide range of magnetic ordering temperatures (up to 400 K). A systematic study of vibrational (both infrared and, for the first time, Raman) properties of the family of new TCNE-based magnets of M(II)(TCNE) (NCMe)(2)[SbF(6)] [M = Mn, Fe, Ni] composition is discussed in conjunction with their magnetic behavior and newly reso-lved crystal structures. The vibrational properties of the isolated TCNE(●-) anion in the paramagnetic Bu(4)N [TCNE(●-)] salt and recently characterized 2D layered magnet Fe(II)(TCNE)(NCMe)(2)[FeCl(4)] are also reported for comparison. Additionally, a linear correlation between ν(C=C) (a(g)) frequency of the TCNE ligand and its formal charge Z (the spin density on the π* orbital), Z = [1571 - ν(C=C) (a(g))]/154.5 [e], is presented. It is shown that monitoring Z by Raman spectroscopy is of great use in providing information that allows understanding the peculiarity of the superexchange interaction in M-[TCNE] magnets and establishing the structure-magnetic properties correlations in this class of magnetic material. 相似文献
68.
Kovnir K Garlea VO Thompson CM Zhou HD Reiff WM Ozarowski A Shatruk M 《Inorganic chemistry》2011,50(20):10274-10283
To explore the evolution of magnetic properties from ferromagnetic LaCo(2)P(2) to paramagnetic LaFe(2)P(2) (both of ThCr(2)Si(2) structure type) a series of mixed composition LaFe(x)Co(2-x)P(2) (x ≤ 0.5) has been comprehensively investigated by means of single-crystal and powder X-ray and neutron diffraction, magnetization and heat capacity measurements, M?ssbauer spectroscopy, and electronic band structure calculations. The Curie temperature decreases from 132 K in LaCo(2)P(2) to 91 K in LaFe(0.05)Co(1.95)P(2). The ferromagnetic ordering is suppressed at higher Fe content. LaFe(0.1)Co(1.9)P(2) and LaFe(0.2)Co(1.8)P(2) demonstrate spin-glass-like behavior, which was also confirmed by the absence of characteristic features of long-range magnetic ordering, namely, a λ-type anomaly in the heat capacity, a hyperfine splitting in the M?ssbauer spectrum, and magnetic reflections in the neutron diffraction pattern. Finally, both LaFe(0.3)Co(1.7)P(2) and LaFe(0.5)Co(1.5)P(2) exhibit paramagnetic behavior down to 1.8 K. The unit cell parameters of the mixed compounds do not follow the Vegard behavior as the increase in the Fe content results in the decrease of average M-M distances (M = Fe, Co). Quantum-chemical calculations and crystal orbital Hamiltonian population analysis reveal that upon aliovalent (nonisoelectronic) substitution of Fe for Co the antibonding character of M-M interactions is reduced while the Fermi level is shifted below the DOS peak in the 3d metal subband. As the result, at higher Fe content the Stoner criterion is not satisfied and no magnetic ordering is observed. 相似文献
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