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Irrigation Water Use Efficiency of Farmers and Its Determinants: Evidence from a Survey in Northwestern china

Agricultural sciences in china 2010年第9期9卷 1326-1337页

作者： WANG Xue-yuan college of Economics, zhejiang Gongshang university, hangzhou 310018, P.R.china college of Economics Zhejiang Gongshang University Hangzhou 310018 P.R. China

Irrigation water shortage is becoming an increasingly serious problem in agricultural production. In this case, it is very important for policy makers to take measures to improve irrigation water use efficiency, especially in the water-scarce areas. In this paper, the data envelopment analysis （DEA） techniques, based on the concept of input-specific technical efficiency were used to develop farm-level technical efficiency measures and sub-vector efficiencies for irrigation water use. The Tobit regression technique was then adopted to identify the factors that influence irrigation water efficiency differentials under the shortage of water resources. Based on a sample data of 432 wheat farmers in northwestern china, our experimental results of the DEA analysis showed the average technical efficiency of 0.6151. It suggested that wheat farmers could increase their production by as much as 38.49% by using inputs more efficiently. Further, the mean irrigation water efficiency of 0.3065, suggested that wheat farmers could produce the same quantity of wheat using the same quantity of inputs but with 69.35% less water. The results of the Tobit regression analysis showed that the farmer＇s age, income, education level, and the farm size tended to affect the degree of irrigation water efficiency positively, and the channel conditions and different irrigation methods made a significant impact on irrigation water use efficiency. Furthermore, the arrangements of exclusive water property rights and competitive water price mechanism have effectively encouraged the water saving behavior of farmers. These results are valuable for policy makers since it could help to guide policies towards high irrigation water use efficiency.

关键词： irrigation water efficiency determinants data envelopment analysis Tobit regression

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Occurrence of nitrification-denitrification and gaseous nitrogen loss process in flooded rice soil

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Progress in Natural science:Materials International 2007年第1期17卷 6-10页

作者： NI Wuzhong, LI Jianping and ZHU Zhaoliang (college of Environmental and Resource sciences, zhejiang university, hangzhou 310029, china college of Biosystems Engineering and Food science, zhejiang university, hangzhou 310029, china Institute of Soil science, Chinese Academy of sciences, Nanjing 210008, china) college of Environmental and Resource sciences Zhejiang University Hangzhou 310029 China college of Biosystems Engineering and Food science Zhejiang University Hangzhou 310029 China Institute of Soil science Chinese Academy of Sciences Nanjing 210008 China

Flooding in wetland rice fields soon after transplanting results in displacement of soil air (including O2). Thus any dissolved O2 in the pore water is consumed out by microbial respiration in a short period. Supply of O2 to the flooded rice soil is by diffusion of O2 through the standing floodwater and consumption at the soil-water interface, and by exudation of O2 by rice roots and subsequent diffusion of O2 into the rhizosphere. The greater potential consumption of O2 compared to the renewal rate results in the development of distinct soil layers: oxidized soil layers under soil-water interface and in the rhizosphere, and reduced soil layers or reduced bulk soil. Nitrification in oxidized soils and denitrification in reduced soils have been known. Currently, denitrification in oxidized soils, even in standing floodwater, has also been identified. In this article, we present a modified nitrification and denitrification occurring mechanism in flooded rice soil.

关键词： denitrification flooded rice soil gaseous nitrogen loss nitrification.

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Tetragonal Domain Switching via Reversible tm Phase Transformation

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Journal of Materials science & technology 1996年第4期12卷 255-260页

作者： Haiyan ZHU and Zhicheng XU(Dept. of Materials science and Engineering, zhejiang university, hangzhou 310027, china) Dept. of Materials science and Engineering Zhejiang University Hangzhou 310027 China

Grinding-induced tm phase transformation and the resultant texture in ceria-yttria-doped tetragonal zirconia polycrystals with varied tetragonality have been studied by XRD. It is observed that the reversible tm phase transformation occurs during grinding and the intensity ratio of I(002)t/I(200)t increases with the transformability. The author proposes that the texture induced by grinding at low temperatures is due to the tetragonal variant reorientation via cyclic,reversible tm phase transformation, termed 'transformational domain switching', instead of the ferroelastic one

关键词： Jun Am Chen Tetragonal Domain Switching via Reversible t m Phase Transformation

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Study on Substrate Specificity at Subsites for Severe Acute Respiratory Syndrome Coronavirus 3CL Protease

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Acta Biochimica et Biophysica Sinica 2005年第12期37卷 807-813页

作者： Yu-Fei SHAN~1 Gen-Jun XU~(1,2)1 Institute of Bichemistry and Cell Biology.Shanghai Institutes for Biological sciences,Chinese Academy of sciences,Shanghai 200031,china 2 college of life science zhejiang Sci-Tech university,hangzhou 310018,china Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200031 China.

Autocleavage assay and peptide-based cleavage assay were used to study the substratespecificity of 3CL protease from the severe acute respiratory syndrome *** was found that therecognition between the enzyme and its substrates involved many positions in the substrate,at least includingresidues from P4 to P2′.The deletion of either P4 or P2′residue in the substrate would decrease its cleavageefficiency *** contrast to the previous suggestion that only small residues in substrate could beaccommodated to the S1′subsite,we have found that bulky residues such as Tyr and Trp were also *** addition,based on both peptide-based assay and autocleavage assay,Ile at the P1′position could not behydrolyzed,but the mutant L27A could hydrolyze the Ile peptide *** suggested that there was astereo hindrance between the S1′subsite and the side chain of Ile in the *** 20 amino acids exceptPro could be the residue at the P2′position in the substrate,but the cleavage efficiencies were *** specificity information of the enzyme is helpful for potent anti-virus inhibitor design and usefulfor other coronavirus studies.

关键词： SARS coronavirus 3CL protease substrate specificity autocleavage binding site inhibitor design

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User-controllable mesh segmentation using shape harmonic signature

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Progress in Natural science:Materials International 2009年第4期19卷 471-478页

作者： Yongwei Miao a,b, Jieqing Fenga, Jinrong Wanga,c, Xiaogang Jin a a State Key Laboratory of CAD & CG, zhejiang university, hangzhou 310027, china b college of science, zhejiang university of technology, hangzhou 310032, china c Information science & Engineering School, hangzhou Normal university, hangzhou 310036, china State Key Laboratory of CAD & CG Zhejiang University Hangzhou 310027 China college of science Zhejiang University of Technology Hangzhou 310032 China Information science & Engineering School Hangzhou Normal University Hangzhou 310036 China

Due to different shape modeling applications, partitioning a given complex 3D mesh model into some patches or meaningful subparts is one of the fundamental problems in digital geometry processing. By using the high-dimensional mean-shift clustering scheme in shape signature space, a new method is proposed which can generate user-specified segmentation results automatically for different applications. The shape signature is composed of mesh geometric attributes and its spectral harmonics. The latter one can reflect mesh frequency spectrum information. The low frequency components are essential for semantics-oriented segmentation, while the high frequency components are important for purely geometry-oriented segmentation. The effects of the proposed method are demonstrated by several examples.

关键词： Mesh segmentation Manifold harmonic analysis Shape harmonic signature Mean-shift clustering

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THREE-SPHERE INEQUALITIES FOR SECOND ORDER SINGULAR PARTIAL DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2010年第3期30卷 993-1003页

作者：张松艳 zhejiang university of science and technology

In this article, we give the three-sphere inequalities and three-ball inequalities for the singular elliptic equation div（A∨u） - Vu =0, and the three-ball inequalities on the characteristic plane and the three-cylinder inequalities for the singular parabolic equation Эtu-div（A∨u）＋ Vu = 0, where the singular potential V belonging to the Kato-Fefferman- Phong＇s class. Some applications are also discussed.

关键词： Three-sphere inequality three-cylinder inequality singular partial differential equation Kato-Fefferman-Phong's class Lipschitz domain

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Expression, Purification and Sublocalization of SARS-CoV Nucleocapsid Protein in Insect Cells

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Acta Biochimica et Biophysica Sinica 2004年第11期36卷 754-758页

作者： Ai-Xia REN, You-Hua XIE, Yu-Ying KONG, Guan-Zhen YANG, Yao-Zhou ZHANG,Yuan WANG, and Xiang-Fu WUInstitute of Biochemistry and Biotechnology, college of life science, zhejiang university, hangzhou 310029, china State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and cell Biology, Shanghai Institutes for Biological sciences,Chinese Academy of sciences, Graduate School of the Chinese Academy of sciences, Shanghai 200031, china Institute of Biochemistry, zhejiang university of sciences, hangzhou 310018, china Institute of Biochemistry and Biotechnology College of Life Science Zhejiang University Hangzhou 310029 China.

The causative agent of severe acute respiratory syndrome (SARS) is a previously unidentified coronavirus, SARS-CoV. The nucleocapsid (N) protein of SARS-CoV is a major viral protein recognized by acute and early convalescent sera from SARS patients. To facilitate the studies on the function and structure of the N protein, this report describe the expression and purification of recombinant SARS-CoV N protein using the baculovirus

关键词： severe acute respiratory syndrome (SARS) SARS coronavirus nucleocapsid protein baculovirus insect cells

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A quasi-physical algorithm for solving the linear separation problem in n-dimensional space

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Journal of Central South university of technology 2001年第4期8卷 272-277页

作者： HUANG Jia yuan (college of Computer science, Huazhong university of science and technology, Wuhan 430074, china) college of Computer science Huazhong University of Science and Technology Wuhan China

A quasi physical algorithm was proposed for solving the linear separation problem of point set in n dimensional *** original idea of the quasi physical algorithm is to find an equivalent physical world for the primitive mathematical problem and to observe the vivid images of the motion of matter in it so as to be inspired to obtain an algorithm for solving the mathematical problem. In this work, the electrostatics with two kinds of matter is found to be the equivalent physical world. As a result,the proposed algorithm is evidently more efficient and robust than the famous LMS algorithm and ETL algorithm. The efficiency of the quasi physical algorithm is about 10-50 times of the LMS algorithm’s for representative instances. A typical Boolean valued instance shows that it is hard for ETL algorithm but very easy for the quasi physical *** this instance, point set A and B is {000, 010, 011, 111} and {001,100}, respectively.

关键词： linear separation problem neural network algorithm quasi-physical method electrostatics

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Mine laneway 3D reconstruction based on photogrammetry

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中国有色金属学会会刊：英文版 2011年第S3期21卷 686-691页

作者： ZHANG Chun-sen college of Geomatics, Xi’an university of science and technology, Xi’an 710054, china college of Geomatics Xi'an University of Science and Technology Xi'an 710054 China

Aiming at the problem of 3D reconstruction for mine laneway, the technique route and step were given based on digital close range photogrammetry and traverse surveying. 3D coordinates of laneway traverse point, photogrammetric station, control strip points were obtained by electronic total station based on mine coordinate system. The feature points were extracted from the scene images. The camera was calibrated by direct linear transformation (DLT). 3D relative coordinates of the arbitrary feature points in mine laneway were calculated after feature points being matched, in which the origin of coordinate system is photogrammetric station. The 3D absolute coordinates of the feature points in mine laneway can be obtained by the combined adjustment of photogrammetry and non-photogrammetric observations and coordinate conversion. The measurable 3D model of the underground laneway terrain surface was constructed with the 3D coordinates of feature points on the image pairs obtained. The measurable 3D model of a corridor was reconstructed by the mentioned method and the experiment precision with an average standard deviation of 0.013 6 m between the 3D model and practical measure was obtained by electronic total station. The experimental resulted show the validity of the proposed approach.

关键词： digital mine mine laneway photogrammetry 3D reconstruction direct linear transformation (DLT)

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Weighted weak type estimates for commutators of the Marcinkiewicz integrals

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science china Mathematics 2004年第1期47卷 83-95页

作者： DING Yong, LU Shanzhen & ZHANG PuDepartment of Mathematics, Beijing Normal university, Beijing 100875, china Department of Information and Computing science, zhejiang Institute of science and technology, hangzhou 310033, china Department of Mathematics Beijing Normal University Beijing China Department of Information and Computing science Zhejiang Institute of Science and Technology Hangzhou China

In this paper the authors give the weighted weak LlogL type estimates for a class of the higher order commutator generated by the Marcinkiewicz integral and a BMO function. In addition, the weak type norm inequalities... 详细信息

关键词： Marcinkiewicz integral, commutator, Ap weight, weak type estimate.

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