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281.
Synthesis
of Pyrrole-Imidazole Polyamide 总被引:1,自引:0,他引:1
Jun Hua XIAO Gu YUAN Wei Qiang HUANG Fei Li TANG Albert S. C. CHAN K.L. Daniel LEE 《中国化学快报》2000,11(3):207-208
Small molecules that target specific predetermined DNA sequences have the potential tocontrol gene expression'. Realization of the high affinity binding and specific recognitionof DNA sequences by organic molecules is one of the focuses of biological chemistry.The natural products netropsin and distamycin are N-methylpyrrole containing di- andtripeptides, with binding specificity at sites of successive A.T or T.A base pairs of DNAin the minor groove'. Recently, N-methylimidazole is intro… 相似文献
282.
Qian ZHANG Ying CHEN Yun Hong ZHENG Wan Yun SHENG Peng XIA* Yi XIA Zheng Yu YANG Kuo Hsiung LEE Department of Organic Chemistry The School of Pharmacy Shanghai Medical University Yi Xue Yuan Road Shanghai Natural Products 《中国化学快报》2001,(1)
Interesting biological activities have been reported recently for 4-methylhydro-2H-pyrano [6,5-h]-chromen-2-ones and 4-methylhydro-2H-pyrano[6,5-h]quinolin-2-ones, including excellent anti-HIV activity with DCK derivatives1 and significant cytotoxic activity with 4,8,8-trimethylhydro-2H-pyrano[6,5-h]quinolin-2-one2. These results prompted us to synthesize two series of corresponding diaza three-ring heterocyclic analogs, trihydro- pyridino[2,3-h]quinolin-2-ones and hydropyridino[2,3-h]quino… 相似文献
283.
There has been growing interest and research on new synthetic methods for thepreparation of well-defined polymers with chain-end functional groups[1~ 7] . Thesefunctional groups in polymers can participate in reversible ionic association;chainextension,branching,or crosslinking reactions with polyfunctional reagents;couplingand linking with reactive groups in other oligomer or polymer chains;and initiation ofpolymerization of other monomers[4~ 6] . The methodology of living anionic polyme-ri… 相似文献
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285.
Multiparty Quantum Secret Sharing of Quantum States Using Entanglement States 总被引:4,自引:0,他引:4
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A multi-partite-controlled quantum secret sharing scheme using several non-orthogonal entanglement states is presented with unconditional security. In this scheme, the participants share the secret quantum state by exchanging the secret polarization angles of the disordered travel particles. The security of the secret quantum state is also guaranteed by the non-orthogonal multi-partite-controlled entanglement states, the participants' secret polarizations, and the disorder of the travelling particles. Moreover, the present scheme is secure against the particle-number splitting attack and the intercept-and-resend attack. It may be still secure even if the distributed quantum state is embedded in a not-so-weak coherent-state pulse. 相似文献
286.
低Mach数流动中,基于可压缩流动的数值模拟算法存在严重的刚性问题,预处理方法可以有效地解决这一问题,但其计算结果不稳定.基于原有的预处理Roe格式,引入可调节参数,得到一种新的低耗散格式.该格式可以减弱边界层以及极低速区域的过度耗散,使得整个流场计算稳定.低Mach数、低Reynolds数定常圆柱绕流和低Mach数、高Reynolds数翼型(NACA0012和S809)绕流3个验证算例表明,带可调节参数的低耗散预处理方法正确可靠,是低速流动数值模拟的有效方法. 相似文献
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288.
NORMAL MODES OF A NON-LINEAR CLAMPED-CLAMPED BEAM 总被引:1,自引:0,他引:1
Non-linear modal analysis approach based on invariant manifold method proposed earlier by Shaw and Pierre (Journal of Sound and Vibration164, 85-124) is utilized here to obtain the non-linear normal modes of a clamped-clamped beam for large amplitude displacements. The results obtained for the fundamental normal mode are compared with the corresponding reported experimental and theoretical studies. The effects of modal coupling are examined in greater detail. The limitation of the present method for analyzing non-linear behavior is highlighted. 相似文献
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