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Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

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Science china Chemistry 2006年第4期49卷 296-307页

作者： LI Ming1, ZHENG Wenxu2.& TIAN Anmin2.1. department of Chemistry, southwest-{2. normal university, chongqing 400715, china 2. department of Chemistry, Sichuan university, Chengdu 610064, china department of Chemistry Southwest-China Normal University Chongqing China department of Chemistry Sichuan University Chengdu China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.

The joint limiting distribution of maxima with random indexes and sums of normal sequence

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西南师范大学学报（自然科学版） 1998年第5期23卷 1-6页

作者： Xie Shengrong department of Mathematics, southwest{2. normal university, chongqing 400715

Ｒｅｃｅｎｔｌｙ，ａｎｕｍｂｅｒｏｆｐａｐｅｒｓｈａｖｅｓｔｕｄｉｅｄｔｈｅｊｏｉｎｔａｓｙｍｐｔｏｔｉｃｉｎｄｅｐｅｎｄｅｎｔｐｒｏｐｅｒｔｉｅｓｏｆ∨ｎ１Ｘｉａｎｄｎ１Ｘｉｏｆｗｅａｋｌｙｄｅｐｅｎｄｅｎｔｓｔ... 详细信息

Ｒｅｃｅｎｔｌｙ，ａｎｕｍｂｅｒｏｆｐａｐｅｒｓｈａｖｅｓｔｕｄｉｅｄｔｈｅｊｏｉｎｔａｓｙｍｐｔｏｔｉｃｉｎｄｅｐｅｎｄｅｎｔｐｒｏｐｅｒｔｉｅｓｏｆ∨ｎ１Ｘｉａｎｄｎ１Ｘｉｏｆｗｅａｋｌｙｄｅｐｅｎｄｅｎｔｓｔａｔｉｏｎａｒｙｓｅｑｕｅｎｃｅ｛...

关键词： joint limiting distribution maximum random index sum normal sequence

Periodic Solutions for Second Order Systems at Resonance

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Acta Mathematica Sinica,English Series 1998年第4期14卷 433-440页

作者： Tang Chunlei, department of Mathematics, southwest normal university,{2., china 西南师范大学数学系重庆

The existence and multiplicity results are obtained for periodic solutions of second order systems at resonance with unbounded nonlinearity. The proofs rely on the minimax methods and an interesting integral inequality.

关键词： Periodic solution Resonance Critical point The (PS) condition The saddle point theorem The generalized mountain pass theorem

A hybrid approach of Knowledge Discovery in fishery resources evaluation

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西南师范大学学报(自然科学版) 1999年第5期24卷 536-544页

作者： Li\ Li department of Computer Science,southwest{2. normal university,chongqing 400715 西南师范大学计算机科学系重庆

A framework is put for ward,which integrates Knowledge Discovery in Database (KDD) with case based reasoning (CBR) and Bayesian *** following tasks are fulfilled:(1)discovering refined rules;(2.retrieving structured data which can not be described by flat vector feature;(3)forecasting the location of central fishing ground for the next *** these have been applied to a real case with some encouraging and interesting results.

关键词： knowledge discovery in databases bayesian network case based reasoning causal network

Resonance Rayleigh scattering study of the interaction of bleomycinA_5 with nucleic acids and its analytical application

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Science china Chemistry 2007年第5期50卷 629-637页

作者： LIU JiangTao1,2. LIU ZhongFang1 & LIU ShaoPu1 1 School of Chemistry and Chemical Engineering, southwest university,{2., china 2.department of Chemistry, Fuling normal university, chongqing 408000, china School of Chemistry and Chemical Engineering Southwest University Chongqing China department of Chemistry Fuling Normal University Chongqing China

The interaction of bleomycinA5 with nucleic acids has been investigated by using resonance Rayleigh scattering (RRS), molecular absorption and fluorescence spectra. The result shows that in near pH 2.2.buffer medium and absence of any metal ions, nucleic acids are capable of binding with bleomycinA5 (BLMA5) to form complexes which can remarkably enhance the RRS intensity and result in batho- chromic and hyperchromic molecular absorption of nucleic acids and fluorescence quenching of bleomycinA5. The RRS spectral characteristics for the binding products of bleomycinA5 with various DNA and RNA are similar, and the maximum RRS peaks are at 301 nm for ctDNA and sDNA, 370 nm for hsDNA, 310 nm for RNAtypeVI and RNAtypeIII, respectively. The increments of RRS intensity are greatly different in which DNA enhances greatly and RNA enhances lightly. In this work, the optimum condi- tions of the interaction and some influencing factors have been investigated. The reaction mechanism and a binding model for the interaction of BLMA5 with the nucleic acids are discussed. In addition, a highly sensitive, simple and rapid new method for the determination of DNA has been developed. The detection limits (3σ) are 5.7 ng/mL for ctDNA, 7.4 ng/mL for sDNA and 9.2.ng/mL for hsDNA, respectively. The method can be applied to determination of trace amounts of DNA.

关键词： bleomycinA5, nucleic acids, resonance Rayleigh scattering, fluorescence quenching, absorption spectrum.

The crystallization and noncrystallization in the diffusion process of Ag ultrafine particles

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西南师范大学学报(自然科学版) 1999年第5期24卷 545-550页

作者： Deng Zhaojing,Zhao Nanrong,Liu Cunye,Li\ Jian department of physics,{2. china normal university,chongqing 400715 西南师范大学物理系重庆

In the diffusion process of Ag ultrafine particles,considerable contents are formed by the spontaneous diffusion evolution process,such as the size distribution evolution,the chemical composition distribution evolution,the crystallization and the non ***,the discussion will be concentrated on the crystallization of the Ag UFP and the non crystallization of the (Ag\-2./Ag) UFP.

关键词： Ag ultrafine particles diffusion process crystallization non crystalliztion

AN EXISTENCE THEOREM OF SOLUTIONS FOR SEMILINEAR ELLIPTIC EQUATIONS ON R^N

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Acta Mathematica Scientia 1999年第3期19卷 289-292页

作者：唐春雷 department of Mathematics Southwest Normal University Chongqing 400715 China

An existent theorem is obtained for nonzero W-1,W-2.R-N) solutions of the following equations on R-N -Delta u + b(x)u = f(x,u), x is an element of R-N, where b is periodic for some variables and coercive for the other... 详细信息

关键词： semilinear elliptic equation periodicity coercivity superlinearity critical point

Maxima with random indexes

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Chinese Science Bulletin 1997年第21期42卷 1767-1771页

作者： XIE Shengrongdepartment of Mathematics, southwest{2. normal university, chongqing 630715,{2. department of Mathematics Southwest China Normal University Chongqing China

LET {ξi} be a sequence of random variables and Mn = =V ξi, which connect asymptoticallysome regularly varying functions. Let {Nn} be a sequence of nonnegative integer-valued ran-dom variables. In this note the limit... 详细信息

关键词： regularly varying function maximum random index.

A spectral theory for generalized locally convex algebras and its applications

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西南师范大学学报(自然科学版) 1999年第5期24卷 511-518页

作者： Jiang Xueyuan,Tang Chunlei,Huang Shaowen department of Mathematics,southwest{2. normal university,chongqing 400715 西南师范大学数学系重庆

A spectral theory is set up for generalized locally convex *** has been proved that the spectral radius formulation and the spectral mapping theorem *** has also been proved that the definition of the spectrum in Allans sense is equivalent to the one in Waelbroecks sense under some natural ***,another spectral theory is set up for linear operators in locally counvex spaces,which is superior to the known one in a sense.

关键词： the spectrum the resolvent the resolvent equation closed element the spectral radius formulation the specrtal mapping theorem