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11.
Adriana Tudose 《Tetrahedron letters》2006,47(48):8529-8533
Simple catalysts formed in situ from palladium acetate and a variety of imidazolium and imidazolinium carboxylates and dithiocarboxylates have been screened in the coupling of aryl halides with trans-2-phenylvinylboronic acid. Imidazol(in)ium carboxylates show an excellent activity, which compares to that displayed by the parent imidazol(in)ium chlorides, whereas imidazol(in)ium dithiocarboxylates are poorly efficient. Interestingly, the base employed exerts a profound influence on the trans/cis stereochemistry of the coupling product. 相似文献
12.
本文基文献 [1]的思路 ,详细论述了利用遗传算法解决有风险控制的最优资产组合问题的具体实现过程 .并论证了用浮点数的方法表示的最优保存遗传算法的全局收敛性 相似文献
13.
The effects of the organometallic compounds Bu2Sn-D -(?;)sorbitol, Bu2Sn-D -(+)glucose, Bu2Sn-D -(?)fructose and Bu2Sn-D -(+)glyceraldehyde were tested in vivo on different stages of Ascidian development, larval movement and metamorphosis. Organotin(IV) complexes are organometallic compounds widely used as industrial biocides, antifouling agents and agricultural fungicides and are toxic to a range of organisms. Two-cell stage embryos, if incubated for one hour in the organotin (IV) solutions, stopped the cleavage, which was restored when they were transferred into normal sea water. The gastrula stage was seriously affected in 10?4mol dm?3 solutions of the above-mentioned complexes: 85% of the embryos were anomalous neurulae with open neural folds, 5% were twisted larvae. The gastrulae, when incubated for 1 h in 10?5mol dm?3 solutions, developed twisted larvae in ovular envelopes and immobile larvae with twisted tails. Larvae treated with 10?4mol dm?3 and 10?5 mol dm?3 Bu2Sn-D -(?)sorbitol, Bu2Sn-D -(+)glucose and Bu2Sn-D -(+)glyceraldehyde solutions stopped swimming, did not metamorphose and afterwards underwent cytolysis. An initial hyperactivity of circular movements, followed by immobility, was observed in the larvae incubated in Bu2Sn-D -(?;)fructose. 相似文献
14.
12 , 169 (1987). Reasonably good agreements in the peak output power and laser efficiency have been achieved. Model calculations
also predict that an efficiency as high as 2.7% can be obtained once the conditions of the above-mentioned experiments have
been optimized. From the consideration that the skin depth effectively limits the absorption length of the microwave pumping
and hence the excitable volume, it is concluded that high input power densities (>2 MW/cm3) and higher gas pressures (between 3 and 10 atm) are the preferable conditions to achieve higher efficiency. Preliminary
calculations on CCl4 containing XeCl gas mixtures show that improvement in laser efficiency by several folds may be achieved as a result of the
higher intrinsic efficiency of excimer formation.
Received: 23 September 1996 / Revised version: 25 March 1997 相似文献
15.
Herve Loïc 《Integral Equations and Operator Theory》1998,32(2):199-215
LetX be a locally compact space, andT, a quasi-compact positive operator onC
0(X), with positive spectral radius,r. Then the peripheral spectrum ofT is a finite set of poles containingr, and the residue of the resolvent ofT at each peripheral pole is of finite rank. Using the concept of closed absorbing set, we develop an iterative process that gives the order,p, ofr, some special bases of the algebraic eigenspaces ker(T-r)
p
and ker(T
*-r)
p
, and finally the dimension of the algebraic eigenspace associated to each peripheral pole. 相似文献
16.
N. Jiten Singh Adriana C. Olleta Anupriya Kumar Mina Park Hai-Bo Yi Indrajit Bandyopadhyay Han Myoung Lee P. Tarakeshwar Kwang S. Kim 《Theoretical chemistry accounts》2006,115(2-3):127-135
In earlier studies, the interactions of isolated ionic species with various solvents were investigated using ab initio calculations.
The ionic species investigated included cations (proton, hydronium, ammonium, and metal cations) and anions (single electron,
hydroxide, and halide anions). However in the present study, we investigate the interactions of these ionic species with the
solvent in the presence of other competing ionic species. We also elaborate on how the information obtained from these extensive
studies have been employed in designing and synthesizing various kinds of novel ionophores and receptors. 相似文献
17.
A. Badalà R. Barbera G. Lo Re A. Palmeri G. S. Pappalardo A. Pulvirenti F. Riggi 《Acta Physica Hungarica A》2006,25(2-4):337-346
Results are shown from a Monte Carlo simulation study of the capabilities of the Inner Tracking System of the ALICE experiment, used in standalone mode, for HBT analysis of Pb?Pb collisions at LHC energies (5.5 ATeV). Different values of the coherence factor and the Gaussian source radius have been studied. For this purpose, a specific ITS stand-alone tracking algorithm, based on the Denby-Peterson neural algorithm, has been developed. 相似文献
18.
19.
20.
In many-valued logic the decision of functional completeness is a basic and important problem, and the thorough solution to this problem depends on determining all maximal closed sets in the set of many-valued logic functions. It includes three famous problems, i.e., to determine all maximal closed sets in the set of the total, of the partial and of the unary many-valued logic functions, respectively. The first two problems have been completely solved ([1], [2], [8]), and the solution to the third problem boils down to determining all maximal subgroups in the k-degree symmetric group Sk, which is an open problem in the finite group theory. In this paper, all maximal closed sets in the set of unary p-valued logic functions are determined, where p is a prime. Mathematics Subject Classification: 03B50, 20B35. 相似文献