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Simplest Normal Forms of Generalized Neimark-Sacker Bifurcation

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Transactions of tianjin university 2009年第4期15卷 260-265页

作者：丁玉梅张琪昌 School of Mechanical Engineering Tianjin University School of sciences Tianjin University of Science and Technology

The normal forms of generalized Neimark-Sacker bifurcation are extensively studied using normal form theory of dynamic system. It is well known that if the normal forms of the generalized Neimark-Sacker bifurcation are expressed in polar coordinates, then all odd order terms must, in general, remain in the normal forms. In this paper, five theorems are presented to show that the conventional Neimark-Sacker bifurcation can be further simplified. The simplest normal forms of generalized Neimark-Sacker bifurcation are calculated. Based on the conventional normal form, using appropriate nonlinear transformations, it is found that the generalized Neimark-Sacker bifurcation has at most two nonlinear terms remaining in the amplitude equations of the simplest normal forms up to any order. There are two kinds of simplest normal forms. Their algebraic expression formulas of the simplest normal forms in terms of the coefficients of the generalized Neimark-Sacker bifurcation systems are given.

关键词： generalized Neimark-Sacker bifurcation simplest normal form near identity nonlinear transformations

Impulsive Homoclinic Chaos in Van der Pol Jerk System

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Transactions of tianjin university 2010年第6期16卷 457-460页

作者：丁玉梅张琪昌 School of Mechanical Engineering Tianjin University School of sciences Tianjin University of Science and Technology

A 3D continuous autonomous chaotic system is reported, which contains a cubic term and six system parameters. Basic dynamic properties of the new Van der Pol Jerk system are studied by means of theoretical analysis and numerical simulation. Based on the Silnikov theorem, the chaotic characterisitics of the dynamic system are discussed. Using Cardano formula and series solution of differential equation, eigenvalue problem and the existence of homoclinic orbit are studied. Furthermore, a rigorous proof for th...

关键词： chaotic system homoclinic orbit Silnikov theorem

Polycistronic strategy for cyanobacterial expression vector construction: Co-transcription of a human gene and a selective marker gene

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Progress in Natural science:Materials International 2005年第9期15卷 798-803页

作者： ZHANG Yukun1, SHI Dingji2, ZHAO Feifei1, YU Meimin1 and RU Binggen1(1. College of Life science, Peking university, Beijing 100871, China 2. College of Marine sciences & Engineering, tianjin university of science & technology, tianjin 300450, China) College of Life science Peking University Beijing 100871 China College of Marine sciences and Engineering Tianjin University of Science and Technology Tianjin 300450 China

A polycistronic expression vector, pKGA-NTF1, was constructed for the cyanobacterium. Within this vector, the spectinomycin/streptomycin resistance gene (aadA) facilitated the selection of transformants when co-transcribed with favorite genes. A natural glnA gene was selected as the platform to introduce the plasmid into a neutral site of the Synechococcus sp. PCC 7002 chromosome. Function of the vector was demonstrated by the insertion of a modified human Trefoil factor 3 gene (NTF1) to upstream of the aadA gene and by the analyses of the transformed strains. Antibiotics resistance assays showed that the dicistronic expression cassette conferred high spectinomycin resistance to both the E. coli cells and the Synechococcus cells. PCR analysis and Western-blot analysis were carried out to confirm the integration and expression of the NTF1 gene, respectively. Through simple molecular manipulations, the artificial polycistronic structure described here can be conveniently used to express other favorable genes or operons in cyanobacteria, and to study the cyanobacterial gene expression as well.

关键词： cyanobacterial transformation human Trefoil factor 3 polycistronic expression Synechococcus sp. PCC 7002 vector construction.

Chloride channel-dependent copper acquisition of laccase in the basidiomycetous fungus Cryptococcus neoformans

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science China(Life sciences) 2010年第1期53卷 125-130页

作者： ZHU ChangWei1,JIANG Nan1,XIAO DongGuang2,PAN Jiao1 & ZHU XuDong1 1 State Key Program of Microbiology and Department of Microbiology,College of Life sciences,Nankai university,tianjin 300071,China 2 tianjin Industrial Microbiology Key Lab,College of Bioengineering,tianjin university of science & technology,tianjin 300457,China State Key Program of Microbiology and Department of Microbiology College of Life Sciences Nankai University Tianjin China tianjin Industrial Microbiology Key Lab College of Bioengineering Tianjin University of Science & Technology Tianjin China

The CLC chloride channel gene CLC-A of the pathogen yeast Cryptococcus neoformans was previously reported to be critical for multicopper laccase activity and growth at an elevated *** study reports that copper homeostasis was impaired in the clc-a *** was demonstrated by the substantial decrease of the intracellular quantity of copper under copper-limited growth as determined by flame atomic absorption ***-A is a critical factor in copper homeostasis which is required for copper acquisition of laccase in ***.

关键词： chloride channel laccase copper homeostasis Cryptococcus neoformans

Molecularly imprinted polymers with assistant recognition polymer chains for bovine serum albumin

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science China Chemistry 2010年第4期53卷 905-911页

作者： GUO MinJie1, GAO Ting1, FAN Zhi1, YAO JingXia1, XIA JianJun2 & MI HuaiFeng2 1Department of Chemistry, College of sciences, tianjin university of science and technology, tianjin 300457, China 2Key Laboratory of Functional Polymer Materials, Ministry of Education Institute of Polymer Chemistry, Nankai university, tianjin 300071, China Department of Chemistry College of Sciences Tianjin University of Science and Technology Tianjin China Key Laboratory of Functional Polymer Materials Ministry of Education Nankai University Tianjin China Institute of Polymer Chemistry Nankai University Tianjin China

A new protein molecularly imprinted polymer (MIP) was prepared with grafting polyvinyl alcohol as assistant recognition polymer chains (ARPCs). The ARPCs and acrylamide monomers were interpenetrated and then polymerized on the surface of macroporous acrylate adsorbent spheres. The template BSA was removed by treatment with 2.00 mol L-1 potassium chloride (KCl) solution and the adsorbed proteins were detected with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). 0.150, 0.500, and 2.00 mol L-1 KCl solutions were used as eluent to wash the adsorbed proteins. The SDS-PAGE results show that proteins washed out with 2.00 mol L-1KCl solution were from nonspecific adsorption of macroporous acrylate adsorbent spheres, and proteins washed out with 0.500 mol L-1KC1 solution were specific proteins imprinted by MIP resins. MIP resins with ARPCs had better recognition to the target proteins than that without ARPCs. The adsorption capacity of MIP resins immobilized ARPCs to the template BSA was about 80-100 μg g-1 when it was used for the adsorption of proteins mixture, and the specific adsorption of the target protein was obviously increased.

关键词： polyvinyl alcohol assistant recognition polymer chains molecular imprinting protein

The Effect of Silica Particle Size on the Performance of Color Ink-jet Printing Paper

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中国造纸 2007年第11期26卷 24-26页

作者： LIU Ye CHEN Yun-zhi (College of Packaging & Printing Engineering,tianjin university of science & technology,tianjin,300222) College of Packaging and Printing Engineering Tianjin University of Science and Technology Tianjin 300222 China

In this paper,the effects of four sorts of silica with the particle size range of 4～10μm on coated paper properties and printing performance were *** results showed that the smaller particle size silica can provide ... 详细信息

关键词： ink-jet printing silica particle size ink-density definition

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论我国中小企业生长的信息环境

图书情报工作 2003年第9期47卷 33-36页

作者：陈大辉天津科技大学图书馆天津300222

在分析我国中小企业信息环境现状的基础上,论述为了改善我国中小企业生长的信息环境,政府、IT以及咨询等行业应当注意的问题及采取的措施。

关键词：中国中小企业信息化网络化电子商务信息环境政府职能信息产业咨询业

Prediction for Dynamic Characteristics of Ring-Plate Planetary Indexing Cam Mechanism

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Transactions of tianjin university 2009年第4期15卷 249-254页

作者：宋轶民田广才张俊刘明涛刘建平 School of Mechanical Engineering Tianjin University Handling Equipment Mechanical Department Academy of Military Transportation School of Mechanical Engineering Tianjin University of Science and Technology

This paper is aimed to propose an approach to predict the dynamic characteristics of ring-plate planetary indexing cam mechanism, which is a novel type of indexing mechanism that employs internal planetary transmission structure. Firstly, the geometry and structure of the mechanism are discussed and the kinematic practicability is simulated with virtual prototype design. Then a 3D finite element model of the ring-plate planetary indexing cam mechanism is developed with the commercial software of MATLAB and ANSYS. Through the finite element analysis, the natural frequencies and the corresponding mode shapes are predicted in one motion cycle. On the basis of the virtual prototype design and finite element analysis, an experimental prototype is made and tested to validate the prediction of the dynamic characteristics. The agreement between experimental results and the finite element analysis testifies that the finite element model developed is applicable to the prediction of the dynamic characteristics of this type of mechanism.

关键词： ring-plate planetary indexing cam mechanism virtual prototype design finite element mode analysis

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家蝇蛹凝集素的分离工艺和性质的初步研究

生物化学与生物物理进展 2003年第3期30卷 442-446页

作者：曹小红陈一张燕陈锦英天津科技大学食品科学与生物工程学院天津300222 天津医科大学基础医学院医学微生物教研室天津300222

通过缓冲液浸提、戊二醛固定化红细胞吸附、亲和层析和凝胶过滤等方法 ,从家蝇蛹中分离纯化出一种对半乳糖专一的凝集素 .结果表明 ,亲和层析后 ,SDS 聚丙烯酰胺凝胶电泳检测家蝇蛹凝集素 (MPL)分子质量为 84ku .SephadexG 2 0 0凝胶过... 详细信息

通过缓冲液浸提、戊二醛固定化红细胞吸附、亲和层析和凝胶过滤等方法 ,从家蝇蛹中分离纯化出一种对半乳糖专一的凝集素 .结果表明 ,亲和层析后 ,SDS 聚丙烯酰胺凝胶电泳检测家蝇蛹凝集素 (MPL)分子质量为 84ku .SephadexG 2 0 0凝胶过滤后 ,MPL分子质量为 86ku .家蝇蛹凝集素专一性识别D 半乳糖 ,其血凝活力对热不稳定 ,不依赖Ca2 +,在 pH 6～ 9之间稳定 .家蝇蛹凝集素对Escherichiacoli。

关键词：家蝇蛹凝集素分离工艺性质抑菌活性血凝活力糖专一性固定化红细胞