Black single crystals of Ta(4)Se(9)I(8) are obtained in a high yield by heating Ta, Se, and I(2) at 300 degrees C in 1:2.2:1.0 molar ratio. In the structure, the tantalum atoms form a square, with four Se(2) ligands bridging the Ta-Ta edges and one capping the square. Each Ta atom has two terminal iodine atoms. The compound is diamagnetic and has only two electrons for metal-metal bonding. 相似文献
An important part of the well-known iterative closest point algorithm (ICP) is the variational problem. Several variants of the variational problem are known, such as point-to-point, point-to-plane, generalized ICP, and normal ICP (NICP). This paper proposes a closed-form exact solution for orthogonal registration of point clouds based on the generalized point-to-point ICP algorithm. We use points and normal vectors to align 3D point clouds, while the common point-to-point approach uses only the coordinates of points. The paper also presents a closed-form approximate solution to the variational problem of the NICP. In addition, the paper introduces a regularization approach and proposes reliable algorithms for solving variational problems using closed-form solutions. The performance of the algorithms is compared with that of common algorithms for solving variational problems of the ICP algorithm. The proposed paper is significantly extended version of Makovetskii et al. (CCIS 1090, 217–231, 2019).
Mechanochemical reaction of cluster coordination polymers
(Q=S, Se) with solid
leads to the cluster core excision with the formation of anionic complexes
. Extraction of the reaction mixture with water followed by crystallization gives crystalline
(main product) and
(1) (minor product). In the case of the Se cluster, the
complex could not be isolated, and the treatment of the aqueous extract with PPh3 gave
(2) in a low yield. Alternatively, it was obtained from
and
in high yield. Both 1 and 2 were characterized by X-ray structure analysis.
Dedicated to Academician I. I. Moiseev on the occasion of his 75th birthday and in recognition of his outstanding contribution
to cluster chemistry. 相似文献
AbstractThe reactivity of the previously reported organonickel σ-complex [NiBr(Mes)(bpy)], where Mes = 2,4,6-trimethylphenyl, bpy = 2,2′-bipyridine, toward phosphine PH3 was investigated. The reaction leads to primary mesitylphosphine MesPH2 as the main product and dimesitylphosphine Mes2PH as secondary product with the nickel complex as transmetalating agent. The formed MesPH2 reacts with an excess of the complex giving Mes2PH as the major product. 相似文献
The effect of a change of noise amplitudes in overdamped diffusive systems is linked to their unperturbed behavior by means of a nonequilibrium fluctuation–response relation. This formula holds also for systems with state-independent nontrivial diffusivity matrices, as we show with an application to an experiment of two trapped and hydrodynamically coupled colloids, one of which is subject to an external random forcing that mimics an effective temperature. The nonequilibrium susceptibility of the energy to a variation of this driving is an example of our formulation, which improves an earlier version, as it does not depend on the time-discretization of the stochastic dynamics. This scheme holds for generic systems with additive noise and can be easily implemented numerically, thanks to matrix operations. 相似文献
All the steps of the proposed technique, from the synthesis of single-source precursors to the preparation of CoPd and CoPt nanoalloys, are described. The double complex salts (DCS) [M(NH3)4][Co(C2O4)2(H2O)2]·2H2O (M = Pd, Pt), which were synthesized by mixing solutions containing [M(NH3)4]2+ cations and [Co(C2O4)2(H2O)2]2− anions, have been used as precursors. The salts obtained were characterized by IR spectroscopy, thermal analysis, XRD and single crystal X-ray diffraction. The prepared compounds crystallize in the monoclinic (space group I2/m, M = Pd) and orthorhombic (space group I222, M = Pt) crystal systems. Thermal decomposition of the salts in helium or hydrogen atmosphere at 200-600 °C results in the formation of nanoalloys powders (random solid solution Co0.50Pd0.50 and chemically ordered CoPt). The size of the bimetallic particles varied from 5 to 20 nm. Order-disorder structural transformations in Co0.50Pt0.50 nanoalloys were studied. The magnetic properties of both chemically disordered Co0.50Pd0.50 and ordered CoPt clusters have also been measured. 相似文献
Synthetic background for the preparation of alkyl substituted maleic anhydrides and maleimides based on radical alkylation of 2,3-dichloromaleic anhydride (maleimide) by hydrocarbons was developed. The best conditions for the selective synthesis of 2-alkyl-3-chloro- and unsymmetrically substituted dialkylmaleic anhydrides were elaborated. 相似文献
The European Physical Journal C - The d-dimensional scalar field action may be reduced, in the background geometry of a black hole, to a two-dimensional effective action. In the near-horizon... 相似文献