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991.
Octanuclear metallocyclic Ni4Fc4 compound: synthesis, crystal structure, and electrochemical sensing for Mg2+ 总被引:2,自引:0,他引:2
New, neutral octanuclearmacrocyclic compound Ni(4)Fc(4) was achieved via self-assembly from Ni(BF(4))(2) and a ferrocene-containing bis-tridentate ligand. The compound exhibits a channeled structure with cavities inside and senses the Mg(2+) electrochemically in the solid state. 相似文献
992.
G-protein coupled receptors (GPCRs) play a key role in different biological processes, such as regulation of growth, death and metabolism of cells. They are major therapeutic targets of numerous prescribed drugs. However, the ligand specificity of many receptors is unknown and there is little structural information available. Bioinformatics may offer one approach to bridge the gap between sequence data and functional knowledge of a receptor. In this paper, we use a bagging classification tree algorithm to predict the type of the receptor based on its amino acid composition. The prediction is performed for GPCR at the sub-family and sub-sub-family level. In a cross-validation test, we achieved an overall predictive accuracy of 91.1% for GPCR sub-family classification, and 82.4% for sub-sub-family classification. These results demonstrate the applicability of this relative simple method and its potential for improving prediction accuracy. 相似文献
993.
994.
With a stereo PIV system, in order to perform reliable measurements of the three velocity components in liquid flow, it is mandatory to minimise the errors made in determining the 2D displacement vectors and the viewing direction of each of the two cameras. We present a method for determining the viewing direction in the angular displacement stereo system by means of a digital imaging procedure such that the direct measurement of geometrical parameters of the set-up is avoided. This makes the method particularly useful for measurements through the transparent walls confining the liquid flow. A third order polynomial used for calibrating the stereo system is shown to provide more accurate results than imaging functions of lower order. Further improvement of the evaluation accuracy is obtained with the application of an artificial neuronal network, but at the expense of considerably increasing the computation time. A comparison of the evaluation results obtained with the operational procedures presented in this paper with those generated with another method that is applicable to liquid flow (Soloff et al. 1997) shows, that the present procedures can be considered as a viable alternative to existing methods. 相似文献
995.
Yoshinori Miyazaki Nobuyoshi Asai Yasushi Kikuchi DongSheng Cai Yasuhiko Ikebe. 《Mathematics of Computation》2004,73(246):719-730
In this paper, it is first given as a necessary and sufficient condition that infinite matrices of a certain type have double eigenvalues. The computation of such double eigenvalues is enabled by the Newton method of two variables. The three-term recurrence relations obtained from its eigenvalue problem (EVP) subsume the well-known relations of (A) the zeros of ; (B) the zeros of ; (C) the EVP of the Mathieu differential equation; and (D) the EVP of the spheroidal wave equation. The results of experiments are shown for the three cases (A)-(C) for the computation of their ``double pairs'.
996.
R. M. Guralnick Cai Heng Li Cheryl E. Praeger J. Saxl 《Transactions of the American Mathematical Society》2004,356(12):4857-4872
Let and be transitive permutation groups on a set such that is a normal subgroup of . The overgroup induces a natural action on the set of non-trivial orbitals of on . In the study of Galois groups of exceptional covers of curves, one is led to characterizing the triples where fixes no elements of ; such triples are called exceptional. In the study of homogeneous factorizations of complete graphs, one is led to characterizing quadruples where is a partition of such that is transitive on ; such a quadruple is called a TOD (transitive orbital decomposition). It follows easily that the triple in a TOD is exceptional; conversely if an exceptional triple is such that is cyclic of prime-power order, then there exists a partition of such that is a TOD. This paper characterizes TODs such that is primitive and is cyclic of prime-power order. An application is given to the classification of self-complementary vertex-transitive graphs.
997.
Fei?Zhangchfli@whu.edu.cn" title="zhangfei@.com chfli@whu.edu.cn" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author Chengfang?Li Lina?Shi 《Optical and Quantum Electronics》2004,36(15):1253-1261
We study a Si-based diode with a p+nn+ structure for picosecond semiconductor closing switch and discuss the physical process, which underlies the operation principle of high-power closing switch based on a delayed breakdown diode (DBD). From the results of numerical simulations and theoretical analysis, single device has demonstrated reliable operation at 2.3 kV, 89 ps risetime, and high output dV/dt(30 kV/ns). As a contribution to the optimal design, some conclusions about trade-off are drawn by changing structure parameters and physical parameters. 相似文献
998.
Dickerson MB Naik RR Stone MO Cai Y Sandhage KH 《Chemical communications (Cambridge, England)》2004,(15):1776-1777
Peptides that promote the rapid, room-temperature precipitation of amorphous germania nanoparticle networks from solution have been identified via use of a combinatorial peptide display library. 相似文献
999.
We report the direct synthesis of a wide range of well-defined, Y-shaped stimulus-responsive block copolymers under mild conditions; the aqueous solution behaviour of these new polymeric surfactants has been investigated. 相似文献
1000.
We present a novel, simple asymptotic expansion for the spectrum of radiation that is backscattered from a laser by a counterpropagating (or copropagating) electron. The solutions are presented in such a way that they explicitly show the relative merit of using an intense laser and of an energetic electron beam in x-ray production in the single particle regime. Simple scaling laws are given. 相似文献