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951.
2-(2- or 4-Pyridyl)ethyl group is readily introduced by pyridylethylation and easily removed after activation by quaternisation with methyl iodide. 相似文献
952.
A new method based on the penalty-function way of satisfying equality constraints is proposed for the determination of constrained
pure state one-electron density matrices for closed-shell many-electron systems. The algorithm suggested can handle many constraints
simultaneously. Certain interesting features of the proposed algorithm are discussed with numerical examples. 相似文献
953.
Abstract— The characteristic near-infrared emission band of O2 (1 Δg ) at 1.28 μ m has been recorded from carbon tetrachloride solutions of the 1, 4-endoperoxides of 1,4-dimethyInaphthalene and 1, 4-dimethoxy-9.10-diphenylanthracene undergoing thermal decomposition. 相似文献
954.
955.
Parametric Cubic Spline Approach to the Solution of a System of Second-Order Boundary-Value Problems 总被引:3,自引:0,他引:3
We use parametric cubic spline functions to develop a numerical method for computing approximations to the solution of a system of second-order boundary-value problems associated with obstacle, unilateral, and contact problems. We show that the present method gives approximations which are better than those produced by other collocation, finite-difference, and spline methods. A numerical example is given to illustrate the applicability and efficiency of the new method. 相似文献
956.
Hallur GurulingappaPhillip Buckhaults Srinivas K. KumarKenneth W. Kinzler Bert VogelsteinSaeed R. Khan 《Tetrahedron letters》2003,44(9):1871-1873
Aminophosphinic acid derivatives were synthesized as potential inhibitors of renal dipeptidase, an enzyme overexpressed in benign and malignant colon tumors. Several compounds showed potent enzyme-inhibitory activity. 相似文献
957.
I. E. Qureshi M. I. Shahzad S. Manzoor M. S. Zafar H. A. Khan 《Radiation measurements》1997,28(1-6):283-286
One of the main advantages of using dielectric track detectors in the study of heavy ion interactions is the possibility of observing each multi-prong event individually with complete kinematical details. It is thus possible to analyze even those reaction channels that have very low branching ratios. In the study of reactions induced by 16.7 MeV/u uranium ions incident on natural gold targets, we have observed 18 four-pronged events in a total detector area of 24 cm2. Using a polynomial range-energy relationship, empirically fitted to the observed data of binary and ternary events, it was possible to perform kinematical analysis of 10 out of 18 events. The masses and relative velocities of the reaction products, determined in this analysis were compared with theoretical prediction based on double sequential fission process. An agreement within one standard deviation with respect to theoretical values has been found for eight analysed events. 相似文献
958.
Anzar Khan Michael Malkoch Martha F. Montague Craig J. Hawker 《Journal of polymer science. Part A, Polymer chemistry》2008,46(18):6238-6254
Hyperbranched polymers were prepared from a variety of mono‐ and difunctional monomers and used in the development of novel UV‐imprint lithography (UV‐IL) resists. The unique physical and chemical properties of these hyperbranched materials significantly increase the range of molecular systems that could be imprinted. Traditional challenges, such as the use of monomers that have low boiling points or the use of insoluble/highly crystalline momomers, are overcome by the preparation of hyperbranched polymers that incorporate these repeat units. In addition, the low viscosity of the hyperbranched macromolecules and the large number of reactive chain ends overcome many difficulties that are traditionally associated with the use of polymeric materials as imprint resists. Hyperbranched polymers containing up to 12 mol % pendant vinyl groups, needed for secondary crosslinking during imprinting, were prepared with a wide range of repeat unit structures and successfully imprinted with features from tens of microns to ∼ 100 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6238–6254, 2008 相似文献
959.
David Barker Anna L. Lehmann Anna Mai Gul S. Khan Eric Ng 《Tetrahedron letters》2008,49(10):1660-1664
A straightforward synthesis of non-symmetrical 3,5-diamidobenzyl amines, ethers and sulfides starting from 3,5-dinitrobenzoic acid is reported. Functionalization of the benzylic position is only achieved after formation of the two amides, otherwise benzylic hydrogenolysis occurs during nitro group reduction. 相似文献
960.