检索结果-南通市图书馆

Extremal problems on the Hua domain of the first type

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第Z1期48卷 343-354页

作者： SU Jianbing & YIN Weiping Mathematics department, Xuzhou normal University, Xuzhou 221116, china Mathematics department, Capital normal University, Beijing 100037, china Mathematics department Xuzhou Normal University Xuzhou China Mathematics department Capital Normal University Beijing China

In this paper we study some extremal problems between the Hua domain of the first type and the unit ball.

关键词： extremal problem, Hua domain of the first type, minimal circumscribed Hermitian ellipsoid.

Extremal problems on the generalized Hua domain of the first type

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第4期16卷 352-358页

作者： SU Jianbing and YIN Weiping department of Mathematics, Xuzhou normal University, Xuzhou 221116, china department of Mathematics, Capital normal University, Beijing 100037, china department of Mathematics Xuzhou Normal University Xuzhou 221116 China department of Mathematics Capital Normal U-niversity Beijing 100037 China

Some extremal problems between the generalized Hua domain of the first type and the unit ball are studied. The extremal mapping and extremal value in explicit formulas are also obtained.

关键词： extremal problem generalized Hua domain of the first type minimal circumscribed Hermitian ellipsoid.

Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1,2, ZHAO Hongmei1 & LI Zonghe1 1. department of Chemistry, Beijing normal University, Beijing 100875, china 2. department of Chemistry, Qujing normal college, Qujing 655000, china Dept. of Chem. Beijing Normal Univ. Beijing 100875 China Dept. of Chem. Qujing Normal Coll. Qujing 655000 China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1 method with partial optimization, the density function theory B3LYP/6-311G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2(CN)C─ N=N─ C(CN)Me2? 2Me2(CN)C?+N2 is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2(CN)CN=N─C(CN)Me2 ? Me2(CN)CN=N?+ Me2(CN)C?? Me2(CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2(CN)C?radical as well as N2 molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).

Synergistic Extraction of Lanthanides by 1-Nitroso-2-Naphthol and Trioctylphosphine Oxide in Paraffin Wax

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2000年第4期19卷 306-311页

作者：郭效军高锦章范海燕彭波王碧邓启良康敬万西北师范大学化学系甘肃兰州 730070 西北师范大学甘肃兰州 730070

The paraffin wax was used as a diluent for 1-nitroso-2-naphthol(HA) and trioctylphosphine oxide(TOPO) in the extraction of lanthanides at 70℃. The composition of the extracted species was given as LnA_3(TOPO)_2 by means of the slope analysis. The variation of the synergistic extraction equilibrium constant(K_ sex) was investigated at 60～80℃, and the thermodynamic data were calculated. The dependence of separation factors on temperature was also studied.

关键词： Synergistic extraction Lanthanides 1-nitroso-2-naphthol Trioctylphosphine oxide

DEGENERATED HOMOCLINIC BIFURCATIONS WITH HIGHER DIMENSIONS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2000年第2期21卷 201-210页

作者： JINYINLAI ZHUDEMINC departmentofMathematics EastChinaNormalUniversityShanghai200062China. departmentofMathematics LinyiTeacherCollegeLinyi276005ShandongChina.

The degenerated homoclinic bifurcation for high dimensional system is considered. The existence, uniqueness, and incoexistence of the 1-homclinic orbit and 1-periodic orbit near　Г are studied under the nonresonant c... 详细信息

关键词： Local coordinates Poincare map Homoclinic orbit Periodic orbit 2-fold periodic orbit Resonant condition

A hybrid approach of Knowledge Discovery in fishery resources evaluation

在线全文

学校读者我要写书评

暂无评论

西南师范大学学报(自然科学版) 1999年第5期 536-544页

作者： Li\ Li department of computer Science,Southwest china normal University,Chongqing 400715

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

Progress in the study of molecular organized assemblies by dielectric relaxation spectroscopy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第3期16卷 221-230页

作者： ZHAO Kongshuang, HE Kejuan and WEI Suxiang (department of Chemistry, Beijing normal University, Beijing 100875, china department of Chemistry, South china normal University, Guangzhou 510631, china) department of Chemistry Beijing Normal University Beijing 100875 China department of Chemistry South China Normal University Guangzhou 510631 China

Because dielectric spectroscopy covers a great many problems in physical and chemical systems occurring in an extremely wide frequency range, the study of this method plays an important role in physical chemistry. As an effective tool to detect inner properties of substance systems, the dielectric spectroscopy method is widely used in chemical systems and has been dramatically developed in recent decade. This review paper describes the applications of the dielectric spectroscopy in the chemical field, and main concentrations are focused on the micelle, microemulsion and other so-called molecular organized assemblies. Some dielectric principles and models proposed for these systems are introduced. In addition, recent technical developments in dielectric spectroscopy and developing trend of this method in other chemical systems are reviewed.

关键词： dielectric relaxation micelle microemulsion vesicle relaxation time.

AN EXTREMAL APPROACH TO BIRKHOFF QUADRATURE FORMULAS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第5期19卷 459-466页

作者： Ying-guang Shi (department of Mathematics, Hunan normal University, Changsha 410081, china) 湖南师范大学湖南长沙 410081

Discusses an extremal problem with Birkhoff interpolation constraints. Quadrature formula derived from an extremal problem; Overview of auxiliary lemmas; Derivation of some properties of polynomials.

关键词： an extremal approach Birkhoff quadrature formulas

Phylogeny of Ptychostomum (Bryaceae,Musci) inferred from sequences of nuclear ribosomal DNA internal transcribed spacer (ITS) and chloroplast rps4

在线全文

学校读者我要写书评

暂无评论

Journal of Systematics and Evolution 2009年第4期47卷 311-320页

作者： ~(1,2)Chen-Ying WANG ~1Jian-Cheng ZHAO~* 1(college of Life Science,Hebei normal University,Shijiazhuang 050016,china) 2(department of Life Science,Zhengzhou Teachers college,Zhengzhou 450044,china) (college of Life Science Hebei Normal University Shijiazhuang 050016 China) (department of Life Science Zhengzhou Teachers College Zhengzhou 450044 China)

The phylogeny of Ptychostomum was first undertaken based on analysis of the internal transcribed spacer(ITS)region of the nuclear ribosomal(nr)DNA and by combining data from nrDNA ITS and chloroplast DNA rps4 *** parsimony,maximum likelihood,and Bayesian analyses all support the conclusion that the reinstated genus Ptychostomum is not *** funkii(Schw(a|¨)gr.)*** (≡Bryum funkii Schw(a|¨)gr.)is placed within a clade containing the type species of Bryum,*** Hedw. The remaining members of Ptychostomum investigated in the present study constitute another well-supported clade. The results are congruent with previous molecular *** the basis of phylogenetic evidence,we agree with transferring *** Mü***.(≡***(Brid.)Turton≡Bryum archangelicum Bruch & Schimp.), Bryum lonchocaulon Mü***.,Bryum pallescens *** Schw(a|¨)gr.,and Bryum pallens *** Ptychostomum.

关键词： Bryum molecular phylogeny nuclear ribosomal DNA internal transcribed spacer sequences Ptychostomum rps4 sequences.