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排序方式: 共有246条查询结果,搜索用时 31 毫秒
61.
P. Rymuza T. Stöhlker D.C. Ionescu F. Bosch C. Kozhuharov D. Liesen T. Ludziejewski A. Krämer P.H. Mokler Z. Stachura P. Świat A. Warczak 《Hyperfine Interactions》1998,114(1-4):171-174
The study of projectile excitation of high-Z ions in collisions with light target atoms is a powerful tool for the investigation of magnetic and higher-order effects
occurring in relativistic collisions. Very first investigations performed for bismuth ions were recently extended at the ESR
storage ring by using He-like uranium ions in collisions with gaseous targets. At the ESR jet target, the absence of solid-state
effects (e.g., multiple collisions) allows one to study higher order processes, such as excitation and ionization or excitation
and capture, occurring in single collisions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
62.
Mariana Stoica Monica Cldraru Alice Cpritz N. I. Ionescu 《Reaction Kinetics and Catalysis Letters》1996,57(1):81-86
The charge transfer at the interface H2-0.5% Pt/Al2O3 was studied by using the transient response of the AC electrical conductance. The transient response for water and oxygen contaminated surface was of the overshoot-type. 相似文献
63.
Rodica E. Ionescu Khalil Abu-Rabeah Serge Cosnier Robert S. Marks 《Electrochemistry communications》2005,7(12):1277-1282
A novel pyrrole-alginate was synthesized providing a gel by Ca2+ cross-linking. The subsequent in situ electrochemical polymerization of the linked pyrrole groups at 0.93 V led to the formation of a composite polypyrrole–gel matrix exhibiting a greater enzyme retention as well as increased alginate stability towards the destructive effect of phosphate anions unlike the natural alginate gel. The presence of the electropolymerized chains was clearly indicated by the decrease of the permeability when compared to natural alginate gel, namely 2.7 × 10−2 and 3.65 × 10−1 cm s−1 respectively, using as an electroactive permeate, hydroquinone. Moreover, the analytical performance of glucose oxidase-based composite alginate for the determination of glucose was determined. 相似文献
64.
N. I. Ionescu M. S. Chirca D. I. Marchidan 《Reaction Kinetics and Catalysis Letters》1989,38(2):249-254
The experimental conditions in which thermal oscillations may be detected during methanol oxidation on palladium catalyst were determined for methanol concentration, oxygen flow rate, temperature of the gaseous reaction mixture and weight of the catalyst sample. Catalyst powder disposal may influence the characteristics of oscillations.
, , , , , , . .相似文献
65.
We perform an experimental and theoretical study on some pyrrolyl-izoxazole derivatives with single bridged donor (D) and acceptor (A) moieties, potentially Twisted Intramolecular Charge Transfer (TICT) state forming compounds. The emission spectra in solvent of different polarities and at different excitation wavelengths were performed. The fluorescence quantum yield is very low and the emission band shifts towards long wavelengths in polar solvents and on increasing the excitation wavelength. Solvent dependent semiempirical calculations were performed. The ground and excited states potential energy surfaces were built in terms of the torsion angle about the single bond joining D and A. The ground states have quasiplanar geometry, but the minimum of the excited states corresponds to the orthogonal conformation, stabilised in methanol due to the large charge separation between the D and A fragments. The possibility of forming TICT excited states for the studied pyrrolyl derivatives is discussed. 相似文献
66.
Gabriela Ionescu Jarl Ivar van der Vlugt Hendrikus C.L. Abbenhuis Dieter Vogt 《Tetrahedron: Asymmetry》2005,16(24):3970-3975
The synthesis of novel chiral tri- and bidentate phosphites 2, 5, 6 and 8, derived from incompletely condensed silsesquioxane backbones and binaphthol, is described. These compounds can be obtained in good yield and are characterized by multinuclear NMR spectroscopy, mass spectrometry and elemental analyses. The complexation with [Rh(cod)2]BF4 has been studied for all bidentate ligands. These nanosized ligands have been applied in the rhodium-catalyzed asymmetric hydroformylation of vinyl acetate and in the rhodium-catalyzed hydrogenation of methyl-(Z)-2-acetamidocinnamate. 相似文献
67.
The paper presents a possible path to the sp(3) BRST Lagrangean formalism for a 1-reducible gauge field theory starting from
the Hamiltonian one. This appears to be not at all a trivial attempt and will allow explanation of the structure of generators
and the form of the master equations in the Lagrangean sp(3) theories. The Freedman-Townsend model, for which a Lagrangean
(covariant) sp(3) theory is important, is presented. 相似文献
68.
We use nonequilibrium molecular dynamics simulations to investigate the structural properties of an oriented melt of n-eicosane under steady-state planar elongational flow. The flow-induced structure was evaluated using the structure factor s(k) taken as the Fourier transform of the total pair correlation function g(r). We found that the equilibrium liquid structure factor is in excellent agreement with the one determined via x-ray diffraction. Moreover, a new x-ray diffraction experiment has been performed on a crystalline n-eicosane sample. The resulting intramolecular contribution to the structure factor was found to be in very good agreement with the simulated one at a high elongation rate, indicating the existence of a possible crystalline precursor structure. 相似文献
69.
In this paper, a macroscopic anisotropic strain rate potential, which can describe both the anisotropy and tension-compression asymmetry of the plastic response of textured metals is derived. This strain rate potential is the exact work-conjugate of the anisotropic stress potential CPB06 of Cazacu et al. (2006). Application of the developed strain rate potential to HCP high-purity alpha-titanium is presented. 相似文献
70.
An overall kinetic model for the deep catalytic oxidation of methanol is presented. It is based on the balance of chemical species and could described self-sustained oscillations.
. .相似文献