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Integrability Condition on an Almost Complex Structure and Its Application

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Acta Mathematica Sinica,English Series 2005年第6期21卷 1459-1464页

作者： Chia Kuei PENG Zi zhou tang(Zizhou tang) Department of Mathematics Graduate School The Chinese Academy of Sciences Beijing 100039 P. R. China School of Mathematical Sciences Beijing Normal University Beifing 100875 P. R. China Department of Mathematical Sciences Tsinghua University Beijing 100084 P. R. China

We obtain and apply a simple form of the integrability condition of an almost complex structure to the Hopf manifolds.

关键词： almost complex structure integrability

An Isometric Embedding of Mbius Band with Positive Gaussian Curvature

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Acta Mathematica Sinica,English Series 2004年第6期20卷 961-964页

作者： Hui Xia HE Zi zhou tang Department of Mathematical Sciences Tsinghua University College of Mathematical Sciences Beijing Normal University

The main purpose of this paper is to show that there is an isometric embedding from M?bius band to ?4 with positive Gaussian curvature.

关键词： Veronese map Gaussian curvature Isometric immersion

Microscale crack propagation in shale samples using focused ion beam scanning electron microscopy and three-dimensional numerical modeling

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Petroleum Science 2023年第3期20卷 1488-1512页

作者： Xin Liu Si-Wei Meng Zheng-Zhao Liang Chun'an tang Jia-Ping Tao Ji-zhou tang aState Key Laboratory of Coastal and Ofshore Engineering Dalian University of TechnologyDalianLiaoning11624China Research Institute of Petroleum Exploration Development China National Petroleum CorporationBeijing100083China State Key Laboratory of Marine Geology Tongji UniversityShanghai200092China

Reliable prediction of the shale fracturing process is a challenging problem in exploiting deep shale oil and gas *** fracture networks need to be artificially created to employ deep shale oil and gas *** distributed minerals and heterogeneities in shales significantly affect mechanical properties and fracturing behaviors in oil and gas *** the actual microstructure and associated heterogeneities in shales constitutes a significant *** RFPA3D(rock failure process analysis parallel computing program)-based modeling approach is a promising numerical technique due to its unique capability to simulate the fracturing behavior of *** improve traditional numerical technology and study crack propagation in shale on the microscopic scale,a combination of high-precision internal structure detection technology with the RFPA^(3D) numerical simulation method was developed to construct a real mineral structure-based modeling ***,an improved digital image processing technique was developed to incorporate actual shale microstructures(focused ion beam scanning electron microscopy was used to capture shale microstructure images that reflect the distri-butions of different minerals)into the numerical ***,the effect of mineral inhomogeneity was considered by integrating the mineral statistical model obtained from the mineral nanoindentation experiments into the numerical *** simulating a shale numerical model in which pyrite particles are wrapped by organic matter,the effects of shale microstructure and applied stress state on microcrack behavior and mechanical properties were investigated and *** this study,the effect of pyrite particles on fracture propagation was systematically analyzed and summarized for the first *** results indicate that the distribution of minerals and initial defects dominated the fracture evolution and the failure *** are generally initiated and propagate

关键词： FIB-SEM Digital imageprocessing Realistic microstructure 3D digital shale fracture process simulation Pyrite

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Chinese Science Bulletin 2010年第8期55卷 701-704页

作者： tang XiaoChan zhou PanPan QIU WenYuan Department of Chemistry State Key Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 China

In this paper,we propose a new 4D graphical representation of DNA primary sequences based on the Z-curve *** advantage of our approach is that it has the similar biological significance with the Z-curve,and it does not lose any biological information of the *** geometrical centers of the 4D graphical representation of DNA sequences are used as the numerical characterizations,and the examination of similarities/dissimilarities about the coding sequences of the first exon of β-globin genes of eleven different species shows that this approach can provide satisfactory results.

关键词： DNA序列图形表示相似性四维 β-珠蛋白基因生物学意义作者编码序列

Synthesis and curing of a novel amino-containing phthalonitrile derivative

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Chinese Chemical Letters 2007年第5期18卷 523-526页

作者： Ke Zeng Ke zhou Wen Rui tang Yan tang Hong Fei zhou Tao Liu Yi Peng Wang Hai Bing zhou Gang Yang State Key Laboratory of Polymer Materials Engineering College of Polymer Science and Engineering Sichuan University Chengdu 610065 China

A novel phthalonitrile derivative containing an amino group, 3,5-bis（3,4-dicyanophenoxy）aniline （CPA）, was synthesized via a nucleophilic displacement of 4-nitrophthalonitrile and 5-aminoresorcinol hydrochloride. The structure of CPA was confirmed by Fourier transform infrared spectra （FT-IR） and nuclear magnetic resonance （^1H NMR）. Thermal analysis performed on CPA revealed that the novel phthalonitrile derivative showed a self-promotion curing behavior and the resulting polymer exhibited outstanding heat-resistance.

关键词： Phthalonitrfle derivative Amino group Self-promotion curing behavior

The Influencing Factors of Disposable Acetylcholinesterase Biosensor for in Situ Detection of Organophosphorus Pesticide

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稀有金属材料与工程 2006年第A3期35卷 389-391页

作者： Xiaowen Xu Xiaohao Wang Fei tang Zhaoying zhou State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua University Beijing 100084 China

An amperometric biosensor based on acetylcholinesterase (ACHE) is assembled by simple adsorption of the AChE on 7,7,8,8-tetracyanoquinodimethane (TCNQ) modified screen-printed *** biosensor is used to detect the inhibitory effect of organophosphorus pesticides on AChE *** detection of organophosphorus pesticides is done with acetylthiocboline chloride (ATCh) as *** order to obtain the optimized response to substrate,the influencing factors of the biosensor are investigated,including temperature,pH,incubation time,substrate concentration and AChE concentration. The measurements were performed after inhibition by immersing the enzyme electrode into the parathion methyl solution. Under the optimized conditions,that is,500 U/ml AChE concentration,pH 7.2,10 min incubation time,2 mmol/L substrate concentration and temperature of 37℃,from 5×10^(-8) mol/L to 5×10^(-5) mol/L is close to linear (regression equation: y(%)=124.055+15.7991gx,R^2=0.99644),which corresponds to 8.7%～56.1% AChE *** the optimized conditions, the lowest detectable amount of parathion methyl is 13×10^(-9).

关键词： biosensor AChE screen-printed electrodes influencing factors organophosphorus pesticides

Disposable Amperometric Acetylcholinesterase Biosensor for the Detection of Organophosphorus Pesticides

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稀有金属材料与工程 2006年第A3期35卷 333-336页

作者： Xiaohao Wang Xiaowen Xu Fei tang Zhaoying zhou State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua University Beijing 100084 China

A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed *** biosensor consisted of an Ag/AgCl reference electrode and a graphite working *** mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on *** detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as *** biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE *** 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode *** biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L *** obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 *** amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).

关键词： amperometric biosensor AChE screen-printed electrodes organophosphorus pesticides

Enantioselective extraction of terbutaline enantiomers by lipophilic tartaric acid

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Journal of Central South University of Technology 2003年第1期10卷 44-48页

作者： tang Ke-wen(唐课文) zhou Chun-shan(周春山) College of Chemistry and Chemical Engineering Central South University Changsha 410083 China Department of Chemistry and Chemical Engineering Yueyang Normal University Yueyang 414000 China College of Chemistry and Chemical Engineering Central South University Changsha 410083 China

Distribution behavior of terbutaline enantiomers was examined in the aqueous and organic solvent of a two-phase system containing L-dibenzoyltartaric acid and lipophilic phase transfer reagent of Na-tetraphenylborate. The influences of pH, organic solvents, concentrations of Na-tetraphenylborate and L-dibenzoyltartaric acid on the partition coefficients and enantioselectivity of terbutaline enantiomers, were investigated. The results show that tetraphenylborate lipophilic anion and terbutaline enantiomers form two lipophilic salt complexes , which facilitates the solubility of the enantiomers in the organic phase. L-dibenzoyltartaric acid forms more stable complexes with enantiomer Ⅱ than with enantiomer I . Enantioselectivity and partition coefficient increase with the addition of the length of alkyl chain of alcohols. pH and concentrations of lipophilic anion and L-dibenzoyltartaric acid influence them obviously and differently.

关键词： L-dibenzoyltartaric acid terbutaline enantiomers chiral extraction

Science and technology innovation promotes realization of university education concept

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The Journal of China Universities of Posts and Telecommunications 2006年第3期13卷 107-109页

作者： MU Wen-jie tang Xin-ying zhou Xiao-guang Beijing University of Posts and Telecommunications Beijing 100876 China

In modem society, universities take on three main functions. Through science and technology innovation, it makes effort to create research achievements needed by society, promotes different modes of technology transfe... 详细信息

关键词： university function technology innovation technology transfer industry