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排序方式: 共有126条查询结果,搜索用时 31 毫秒
1.
U. Röthlisberger W. Andreoni 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,20(1):243-246
We present the results of ab-initio molecular dynamics studies of selected microclusters of sodium, silicon and magnesium at finite temperatures, and especially discuss those obtained around room temperature. In particular, from the analysis of the atomic trajectories we can identify in some cases the existence of different isomers and the isomerization pathways. We have also calculated vibrational spectra at low temperatures and find that they can be used as a very sensitive structural probe also in sodium clusters, where the electronic properties are quite insensitive to the geometry. 相似文献
2.
A. Vecchio Carlo Finoli Damiano Di Simine Vincenza Andreoni 《Fresenius' Journal of Analytical Chemistry》1998,361(4):338-342
Microbial biomass provides available ligand groups on which metal ions bind by different mechanisms. Biosorption of these
elements from aqueous solutions represents a remediation technology suitable for the treatment of metal-contaminated effluents.
The purpose of the present investigation was the assessment of the capability of Brevibacterium sp. cells to remove bivalent ions, when present alone or in pairs, from aqueous solutions, using immobilized polyacrylamide
cells of the microorganism in a flow-through system. The biosorption capacity of Brevibacterium cells was studied for lead, cadmium and copper. The metal cell binding capacity followed the order Cu > Pb > Cd, based on
estimated qmax. These values, expressed as mmol metal/g dry weight cells, were 0.54 for Cu, 0.36 for Pb and 0.14 for Cd. Polyacrylamide-gel
immobilized cells were effective in Pb, Cu and Cd removal. Lead removal was not affected by the presence of Cd and Cu; lead
instead inhibited Cd and Cu removal. The desorption of the metal, by fluxing a chelating solution, restored the metal binding
capacity of the cells, thus affording the multiple use of the same biomass in the remediation treatment.
Received: 31 July 1997 / Revised: 22 December 1997 / Accepted: 30 December 1997 相似文献
3.
Summary In this paper we discuss the existence of compact attractor for the abstract semilinear evolution equation u=Au+f(t, u); the results are applied to damped partial differential equations of hyperbolic type. Our approach is a combination of Liapunov method with the theory of -eontractions. 相似文献
4.
Suely L. Galdino Maria C. A. Lima Alexandre J. S. Góes Ivan R. Pitta Cuong Luu-Duc 《光谱学快报》2013,46(7-8):1013-1021
In the present investigation, a study of the electron impact mass spectrometry data is reported for seven compounds of a series of some 3-(4-chlorobenzyl)-5-benzylidene-imidazolidine-2, 4-diones and 3-(4-fluoro or chlorobenzyl)-5-benzylidene-thiazolidine-2, 4-diones previously synthesized. 相似文献
5.
Guillaume Erbland Dr. Seifallah Abid Yohan Gisbert Nathalie Saffon-Merceron Yuichiro Hashimoto Leonardo Andreoni Théo Guérin Dr. Claire Kammerer Prof. Dr. Gwénaël Rapenne 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16328-16339
The design and synthesis of two families of molecular-gear prototypes is reported, with the aim of assembling them into trains of gears on a surface and ultimately achieving controlled intermolecular gearing motion. These piano-stool ruthenium complexes incorporate a hydrotris(indazolyl)borate moiety as tripodal rotation axle and a pentaarylcyclopentadienyl ligand as star-shaped cogwheel, equipped with five teeth ranging from pseudo-1D aryl groups to large planar 2D paddles. A divergent synthetic approach was followed, starting from a pentakis(p-bromophenyl)cyclopentadienyl ruthenium(II) complex as key precursor or from its iodinated counterpart, obtained by copper-catalyzed aromatic Br/I exchange. Subsequent fivefold cross-coupling reactions with various partners allowed high structural diversity to be reached and yielded molecular-gear prototypes with aryl-, carbazole-, BODIPY- and porphyrin-derived teeth of increasing size and length. 相似文献
6.
By using calculations based on density functional theory, we investigate the physical factors determining the elemental charge transfer in Alq3, taken as a prototype of molecular systems in condensed phase. The effect of the environment on the hopping of the charge carrier is evaluated self-consistently in a model in which an Alq3 dimer is embedded in an ensemble of permanent and polarizable dipoles, including orientational disorder and the presence of impurities. The results indicate that the origin of the activation barrier is mainly extrinsic and that the local orientation of the dipole moments plays a major role. The influence of nonadiabaticity is also studied and found to be more important for a hole than for an electron. 相似文献
7.
Summary A methodology aimed at improving the accuracy of current docking–scoring procedures is proposed, and validated through detailed tests of its performance in predicting the activity of HIV-1 protease inhibitors. This methodology is based on molecular dynamics simulations using a force field whose effective charges are refined by means of a novel procedure that relies on quantum-mechanical calculations and preserves the internal consistency of the parameterization scheme. 相似文献
8.
Second-harmonic-generated holograms directly provide the outputs of logical gates AND and NAND operating on optical bits encoded as amplitude modulations in the object and reference wave fronts. By use of a Nd:YAG laser and a beta-barium borate crystal, we realized a real-time half-adder of two one-digit binary numbers. The feasibility of highly parallel operation is also discussed. 相似文献
9.
10.
Large-scale classical and quantum simulations are used to generate a-Si:H structures. The bond-resolved density of the occupied electron states discloses the nature of microscopic defects responsible for levels in the gap. Highly strained bonds give rise to band tails and midgap states. The latter originate mainly from stretched bonds, in addition to dangling bonds, and can act as hole traps. This study provides strong evidence for photoinduced degradation (Staebler-Wronski effect) driven by strain, thus supporting recent work on a-Si, and sheds light on the role of hydrogen. 相似文献