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LYOTROPIC AND THERMOTROPIC LIQUID CRYSTALL INE TRIALKYL CELLULOSES OBTAINED DIRECTLY FROM CELLULOSE ACETATE IN DIMETHYL SULFOXIDE

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Chinese Chemical Letters 1992年第7期3卷 573-576页

作者： Xin Gui LI, and Mei Rong HUANG~1 institute of Membrane Separation Engineering, ~1department of Textile Chemical Engineering, tianjin institute of Textite Science and Technology, tianjin 300160

Highly substituted n-atkyl celluloses with sidechains 3 to 10 carbon atoms long have been prepared from cellulose acetate, sodium hydroxide and n-alkyl bromides with dimethyl sulfoxide as solvent. Synthetic conditions of n-alkyl celluloses were studied with respect to reaction temperature, time and yield. The molecular structure of the n-alkyl celluloses, which were obtained as white powders or as sticky, soft and birefringent solids at room temperature, was investigated by IR and NMR spectra and elemental analysis. The highly substituted n-alkyl celluloses all exhibited both therotropic and lyotropic liquid crystalline cholesteric phases in some non-polar solvents. The metting behavior and solubility of the n-alkyl celluloses were examined.

关键词： LYOTROPIC AND THERMOTROPIC LIQUID CRYSTALL INE TRIALKYL CELLULOSES OBTAINED DIRECTLY FROM CELLULOSE ACETATE IN DIMETHYL SULFOXIDE

Crossed Micro-bands in the Martensite Variant Pairs of a Thermomechanically Trained Cu-Zn-Al Alloy

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Journal of Materials Science & Technology 1995年第6期11卷 418-420页

作者： Qingan ZHANG and Nanju GU (Hebei institute of Technology tianjin, 300130, china)(East china institute of Metallurgy,Ma’anshan, 243002, china) Hebei Inst of Technology Tianjin China

The crossed micro-bands in the martensite variant pairs of a thermomechanically trained Cu25.66Zn-4.02Al (wt-%) alloy have been studied. It was found that the micro-bands pass through the interface from one martensite variant to another and their orientation inside different variants is distinct, which would remain in the parent phase after the reverse transformation and play an important role in the formation of preferential martensite. In fact, the crossed micro-bands are micro-twins for accommodating the stress fields generated during thermomechanically training

关键词： Zn Al Crossed Micro-bands in the Martensite Variant Pairs of a Thermomechanically Trained Cu-Zn-Al Alloy Cu

INVESTIGATION ON THE FLOW STABILITY OF NEWTONIAN FLUID IN ECCENTRIC ANNULUS VIA THE AXIAL RECIPROCATION OF THE INNER TUBE

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Journal of Hydrodynamics 2007年第6期19卷 671-676页

作者： YUAN Ai-wu CUI Hai-qing GAO Tao Management institute Tianjin University Tianjin 300072 China department of Petroleum Engineering Daqing Petroleum Institute Daqing 163318 China Daqing Exploration and Development institute Daqing 163712 China

The governing equation, together with the formulas of the averaged flux and the stability parameter for Newtonian fluid flowing in eccentric annulus via the axial reciprocation of the inner tube was established in the bipolar coordinate system. Numerical calculation was conducted for the measurement of water flow using the formulas above, of which the results agree well with the experimental data. It is shown that the flow instability can be induced by the increase of the stroke, the frequency, and the eccentricity of annulus, making the sucker rod more susceptible to partial abrasion. Some protecting methods, including adding centralizers, adjusting the stroke and frequency, are proposed to protect the sucker rod from the partial abrasion, and satisfactory results have been achieved in the oilfields.

关键词： eccentric annulus axial reciprocation flow stability partial abrasion

Experimental Study on Dimethyl Ether Combustion Process in Homogeneous Charge Compression Ignition Mode

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Transactions of tianjin University 2004年第4期10卷 241-246页

作者：郑尊清史春涛尧命发 State Key Laboratory of Engines Tianjin UniversityTianjin 300072 China tianjin Internal Combustion Engine Research institute Tianjin University Tianjin 300072 China

Experimental study on homogeneous charge compression ignition （HCCI） combustion process was carried out on a single-cylinder direct injection diesel engine fueled with dimethyl ether（DME）. The influence of inert gas CO2 on the ignition and combustion process was investigated. The research results indicate that because of the high cetane number of DME, the stable HCCI operating range is quite narrow while the engine has a high compression ratio. The HCCI operating range can be largely extended when the inert gas is inducted into the charging air. HCCI combustion of DME presents remarkable characteristic of two-stage combustion process. As the concentration of inert gas increases, the ignition timing of the first combustion stage delays, the peak heat release rate decreases, and the combustion duration extends. Inducting inert gas into charging air cannot make the combustion and heat release of DME occur at a perfect crank angle position. Therefore,to obtain HCCI operation for the fuel with high cetane number,other methods such as reducing engine compression ratio should be adopted. Emission results show that under HCCI operation, a nearly zero NOx emission can be obtained with no smoke emissions. But the HC and CO emissions are high, and both rise with the increase of the concentration of inert gases.

关键词： homogeneous charge compression ignition (HCCI) dimethyl ether(DME) combustion emission

Androgen and prostatic stroma

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Asian Journal of Andrology 2003年第1期5卷 19-26页

作者： Yuan-Jie NIU, Teng-Xiang MA, Ju ZHANG, Yong XU, Rui-Fa HAN, Guang SUNdepartment of Prostatic Disease, tianjin institute of Urologial Surgery, tianjin Medical University,tianjin 300211, china department of Prostatic Disease Tianjin Institute of Urologial Surgery 23 Pingjiang Road Hexi District Tianjin 300211 Chin

Aim: To investigate the effect of androgen on the proliferation, differentiation and regression of canine prostatic stromal cells in vivo and human stromal cells in vitro. Methods: Twenty-two dogs, including 15 normal prostate dogs and 7 prostatic hyperplasia dogs, had their serum concentration of testosterone and estrodiol determined by radioimmunoassay before and after castration. The expression of androgen receptor (AR) and estrogen receptor (ER) in the prostate were analysed by immunohistochemistry and semi-quantitative RT-PCR before and after castration. Light microscopy, transmission electron microscopy and TUNEL assay were carried out successively before and after castration to evaluate the prostatic histomorphology. In vitro serum-free cell cultures from human prostatic stroma were established and exposed to dihydrotestosterone (DHT). The proliferation of the cell culture was detected by MTT assay. The expression of TGFβ, bFGF, AR, and smooth muscle cell (SMC) specific proteins (myosin and/or smoothelin) were detected using immunohistochemistry and RT-PCR. The differentiation from fibroblasts to smooth muscle cells was deduced by measuring the expression of SMC specific proteins. Results: Before castration, the serum concentrations of testosterone and estrodiol were not statistically different between normal and hyperplasia groups. Following castration, the serum concentration of testosterone decreased rapidly in 2 days, and the concentration of estrodiol had no significant change compared with the pre-castration data. In the prostate, AR was presented in both the epithelial and stromal cells and the AR mRNA level was higher in hyperplasia than in normal prostate tissues (P<0.05). While ER predominantly existed in the prostate stromal cells and the ER mRNA had no difference between the hyperplasia and the normal group. Within the early phase of castration (

关键词： androgen castration androgen receptor prostatic stroma smooth muscle cells

Linguistic granular model: design and realization

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Progress in Natural Science:Materials International 2005年第8期15卷 749-756页

作者： YUE Shihong 1,2*, LI Ping2 and SONG Zhihuan2(1. institute of Industrial Process Control, Zhejiang University, Hangzhou 310027, china 2. School of Electric Engineering and Atomization, tianjin University, tianjin 300072, china) institute of Industrial Process Control Zhejiang University Hangzhou 310027 China. School of Electric Engineering and Atomization Tianjin University Tianjin 300072 China

A new linguistic granular model is proposed and the effect of its parameters on the output is analyzed. The design of the model consists of two stages: using conditional fuzzy clustering for information granular, and integrating all information granules to final output. The integrating tool is fuzzy integral based on fuzzy measure, and the generalization of fuzzy integral increases flexibility of the linguistic granular model greatly. A heuristic algorithm to determine the parameters in the fuzzy integral is used to realize the linguistic model. Two experiments verify the feasibility of the proposed model.

关键词： linguistic model granular fuzzy clustering fuzzy integral.

The Degree of Symmetry of Certain Compact Smooth Manifolds II

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Chinese Annals of Mathematics,Series B 2007年第2期28卷 195-204页

作者： Bin XU department of Mathematics, University of Science and Technology of china, Hefei 230026, china Chern institute of Mathematics, Nankai University, tianjin 300071, china department of Mathematics, Johns Hopkins University, Baltimore, MD 21218, USA. department of Mathematics University of Science and Technology of China Hefei 230026 China Chern institute of Mathematics Nankai University Tianjin 300071 China department of Mathematics Johns Hopkins University Baltimore MD 21218 USA

We give the sharp estimates for the degree of symmetry and the semi-simple degree of symmetry of certain compact fiber bundles with non-trivial four dimensional fibers in the sense of cobordism, by virtue of the rigidity theorem of harmonic maps due to Schoen and Yau (Topology, 18, 1979, 361-380). As a corollary of this estimate, we compute the degree of symmetry and the semi-simple degree of symmetry of CP2×V, where V is a closed smooth manifold admitting a real analytic Riemannian metric of non-positive curvature. In addition, by the Albanese map, we obtain the sharp estimate of the degree of symmetry of a compact smooth manifold with some restrictions on its one dimensional cohomology.

关键词： Degree of symmetry Fiber bundle Cobordism Non-positive Curvature Harmonic map First cohomology

A Brief Discussion of Contemporary American Realistic Short Stories

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兰州大学学报（社会科学版） 2000年第S1期28卷 192-195页

作者： HT5SS]Guo Hong 1 Xu Ming 2 (1 Foreign Languages department, Northwest Normal University, Lanzhou, 730070 2 Foreign Languages department, tianjin Engineering institute, tianjin, 300191, china)

On the contemporary scene of American literature, realism remains one of the main modes of expressions. Apart form realistic thematic concerns, the American post war realistic short fiction also exhibits its nature by successful portrayal of a whole gallery of typical characters. In this essay, some major works are brought under the discussion.

关键词： post-wary American short stories realistic typical

A method of analysis of macro water environmental systems

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Journal of Environmental Sciences 1994年第4期6卷 496-503页

作者： Bao Jingling (tianjin institute of Environment Protection Science, tianjin 300191 china) Yang Baochen Zhang Shiying(department of Engineering Economics & Systems Engineering,tianjin University, tianjin 300072, china)

The phases of water environmental system (WES) and their emphatic intersections areanalysed in this paper. and from the view point of system analysis , an analytical process of WES is provided. Based on the balance network of WES, a goal programming model for regional water environmentalplanning and the main computational result for a coastal city are provided , thus proving its usefulness andeffectiveness.

关键词： water environmental system balance network of water environmental system goal program-ming.