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The GPS-gravimetry boundary value problem

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Science china Earth Sciences 2005年第3期48卷 398-405页

作者： YU Jinhai1,2.& ZHANG Chuanding2.1. Institute of Geodesy and Geophysics of Chinese Academy of Sciences, Wuhan 430077, china 2. zhengzhou Information {2. university, zhengzhou 450052. china 1. Institute of Geodesy and Geophysics of Chinese Academy of Sciences 430077 Wuhan China 2. zhengzhou Information engineering {2. 450052 Zhengzhou China

How to determine the earth’s external gravity field with the accuracy of O(T2. by making use of GPS data and gravity values measured on the earth’s surface is dealt with in this paper. There are two main steps: to extend these measured values on the earth’s surface onto the reference ellipsoid at first and then to seek for the integral solution of the external Neumann problem outside the ellipsoid. In addition, the corresponding judging criteria of accuracy to solve the GPS-gravity boundary value problem are established. The integral solution given in the paper not only contains all frequency-spectral information of the gravity field with the accuracy of O(T 2., but is also easily computed. In fact, the solution has great significance for both theory and prac- tice.

关键词： Neumann boundary value problem, integral solution, gravity disturbance.

Effects of Al on Microstructure and High-Temperature Wear Properties of Austenitic Heat-Resistant Steel

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Journal of Iron and Steel Research International 2012年第3期19卷 62-66页

作者： ZHANG Yan1, SUN Yu-fu2. ZHAO Jing-yu2. GUAN Shao-kang2.(1. School of Materials engineering, Nanjing Institute of Technology, Nanjing 2.1167, Jiangsu, china 2. School of Materials Science and engineering, zhengzhou university, zhengzhou 450002. Henan, china) [a] School of Materials engineering Nanjing Institute of Technology Nanjing 211167 Jiangsu China [b] School of Materials Science and engineering Zhengzhou University Zhengzhou 450002 Henan China

Microstructure and high-temperature dry sliding wear at 600 ~C in ambient air of austenitic heat-resistant steel ZG40Cr2.Ni2. with different contents （mass percent） of AI （0 to 7.10~） have been investigated. The results show that microstructures of 4.68% and 7.10% A1 addition content consist of the matrix and reinforcement of inter- metallic compound y＇ and carbide, while microstructures of ZG40Cr2.Ni2. without A1 and with A1 of 1.68% are ab- sent of y＇. Higher wear resistance than the original ZG40Cr2.Ni2. alloy is achieved in alloys with higher content of A1 under the same high-temperature wear test condition. The wear rates of Fe-2.Cr-2.Ni-7.10A1 and Fe-2.Cr-2.Ni- 4.68A1 are only 2..83% and 45.83% of that of Fe-2.Cr-2.Ni, respectively. Heat-resistant steels with higher con- tents of AI （4.72. and 7.10%） have higher hardness than those with lower contents of AI （1.68% and 0）. Wear mechanisms of ZG40Cr2.Ni2. are considered as severe plough plastic deformation and slight adhesive. However, wear mechanisms of Fe-2.Cr-2.Ni 4.68A1 are light micro-cutting and oxidation-wear, while that of Fe-2.Cr-2.Ni- 7. 10A1 are severe adhesive transfer and oxidation-wear_

关键词： austenitic heat resistant steel Al microstructure high-temperature sliding wear mechanism

Local and Global Character Sums

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Acta Mathematica Sinica,English Series 2000年第3期16卷 535-540页

作者： Chunlei Liu zhengzhou university of Information engineering,{2. 450002.P.R.china zhengzhou university of Information {2. Zhengzhou 450002 P. R. China

Hua’s estimate is established for character sums in a number field.A relationship between liftings of a character sum in a local field is also studied.

关键词： Character sum Exponential sum

Controlled free radical polymerization of styrene initiated from the alkoxyamine-functionalized silicon surface

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Science china Chemistry 2005年第5期48卷 449-458页

作者： CHEN Zhijun1, ZHOU Sikai1, LU Wenzhong1, FANG Shaoming1, JIANG Xiqun2.& YANG Changzheng2.1. college of Materials and Chemical engineering,{2. of Light Industry, zhengzhou 450002. china 2. Laboratory of Mesoscopic Material Science and Department of Polymer Science & engineering, college of Chemistry & Chemical engineering, Nanjing university, Nanjing 2.0093, china 1. college of Materials and Chemical engineering Zhengzhou University of Light Industry 450002 Zhengzhou China 2. Laboratory of Mesoscopic Material Science and Department of Polymer Science & engineering College of Chemistry & Chemical Engineering Nanjing University 210093 Nanjing China

We describe a new method of fabricating a brush-like polystyrene layer anchored on the surface of the silicon substrate, which involves three steps, namely (i) the attachment of 3-methacryloxypropyltrimethoxysilane onto the silicon surface; (ii) the reaction of vinyl moiety at another extremity of the anchored 3-methacryloxypropyltrimethoxysilane to 4-Hydroxyl-2. 2. 6, 6-tetramethyl-1-piperidinyloxy (HTEMPO?) catalyzed by azobisisobutyronitrile (AIBN); (iii) living free radical grafting polymerization of styrene in the presence of HTEMPO?. The controllable living free radical polymerization permits accurate control of both the molecular weight and the polydispersity. X-photoelectron spectroscopy measurement proved that the alkoxyamine initiator layer forms on the silicon surface. XPS and Ellipsometry measurements showed that the poly-styrene chains were covalently anchored onto the silicon surface. The thickness of the grafted polymer layer can be accurately manipulated by altering the polymerization time. The new method allows synthesizing random copolymer and block copolymers by the sequential growth of monomers from the substrate surface.

关键词： polymer brush, controlled living free radical polymerization, thickness, atomic force microscopy, 3-methacryloxypropyltrimethoxysilane.

Genetic analysis of segregation distortion of mating-type factors in Lentinula edodes

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Progress in Natural Science:Materials International 2005年第8期15卷 684-688页

作者： CHENG Shuiming 1,2. LIN Fanxue1, XU Xuefeng1, LI Anzheng1 and LIN Fangcan1*(1. State Key Laboratory of Agricultural Microbiology and Institute of Applied Mycology, Huazhong Agricultural university, Wuhan 430070, china 2. National {2. Research Center For Wheat, Henan Agricultural university, zhengzhou 450002. china) State Key Laboratory of Agricultural Microbiology and Institute of Applied Mycology Huazhong Agricultural University Wuhan 430070 China. National engineering Research Center For Wheat Henan Agricultural University Zhengzhou 450002 China

Analyses of the mating-type ratio of protoplast monokaryons to spores in 2. strains of Lentinula edodes were performed through statistical methods. The results showed that the segregation distortion phenomenon commonly exists in both types of Lentinula edodes, 17 out of the 2. samples did not display the expected 1∶1 ratio of protoplast monokaryons; and among them 8 fruiting strains distorted 1∶1∶1∶1 segregation of spores. The degree of distortion in all tested wild strains was significantly lower than that of cultured strains. In fruiting test of positive-negative parent, predominant spores were those with the mating type identical to dikaryotic parent, indicating that the predominance of nuclei mainly depends on the mating type of dikaryotic parent. Data from di-mon mating test verified that monokaryons with acceptor nuclear type are present exclusively in a large amount after dedikaryotization, suggesting that the specificities among B factors and some other unknown factors in cytoplasm are probably responsible for the phenomenon of skewed segregation.

关键词： Lentinula edodes mating-type factors segregation distortion cytoplasm.

A single observer location method under the scatter signals position disturbance situation:the constraint total least square method

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Science china(Information Sciences) 2011年第1期54卷 146-152页

作者： YANG TianChi1,YU ChaoQun2.WANG TianPeng1 & JIN Liang1 1National Digital Switching System engineering and Technological Research Center, zhengzhou {2.china 2.urveying and Mapping college of Information engineering university, zhengzhou {2.china 1. National Digital Switching System engineering and Technological Research Center Zhengzhou 450002 China2. Surveying and Mapping College of Information Engineering University Zhengzhou 450002 China

A target position can be estimated using position information from scattered signals in the nonline-of-sight propagation environment in a single observer location *** is always an error in the final estimated result of the position obtained using scatter signals because measurement noise is *** reduce the total error of the system,we propose a method of converting the problem of optimizing location into a one of solving the extremes of the *** the problem of how to solve the extremes of the constraints is converted into an unconstrained problem by using the constrained total least squares(CTLS) ***,the Newton iteration method is used to obtain the optimized *** results also verify the capability of this method.

关键词： scatter position disturbing VOCTLS single observer location Newton iteration

A new approach based on PSO algorithm to find good computational encoding sequences

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Progress in Natural Science:Materials International 2007年第6期17卷 712-716页

作者： Cui Guangzhao1, Niu Yunyun1, Wang Yanfeng1, Zhang Xuncai2.and Pan Linqiang2.1. School of Electrical and Electronic engineering, zhengzhou university of Light Industry,{2. 2. Research Institute of Biomolecular Computer, Huazhong university of Science and Technology, Wuhan 430074, china) [a]School of Electrical and Electronic engineering Zhengzhou University of Light Industry Zhengzhou China [b]Research Institute of Biomolecular Computer Huazhong University of Scienc and Technology Wuhan China

Computational encoding DNA sequence design is one of the most important steps in molecular computation. A lot of research work has been done to design reliable sequence library. A revised method based on the support system developed by Tanaka et al. is proposed here with different criteria to construct fitness function. Then we adapt particle swarm optimization (PSO) algorithm to our encoding problem. By using the new algorithm, a set of sequences with good quality is generated. The result also shows that our PSO-based approach could rapidly converge at the minimum level for an output of the simulation model. The celerity of the algorithm fits our requirements.

关键词： DNA computing computational encoding DNA sequences PSO algorithm fitness function

A fingerprint feature extraction algorithm based on curvature of Bezier curve

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Progress in Natural Science:Materials International 2007年第11期17卷 1376-1381页

作者： Yuan Huaqiang1, Ye Yangdong2. Deng Jianguang2. Chai Xiaoguang1 and Li Yong1(1. School of Software, Dongguan university of Technology, Dongguan 52.808, china 2. Information {2. Institute, zhengzhou university, zhengzhou 450001, china) School of Software， Dongguan university of Technology， Dongguan 52.808， china Information engineering Institute， zhengzhou university， {2. 450001， china

Fingerprint feature extraction is a key step of fingerprint identification. A novel feature extraction algorithm is proposed in this paper, which describes fingerprint feature with the bending information of fingerprint ridges. Ridges in the specific region of fingerprint images are traced firstly in the algorithm, and then these ridges are fit with Bezier curve. Finally, the point that has the maximal curvature on Bezier curve is defined as a feature point. Experimental results demonstrate that this kind of feature points characterize the bending trend of fingerprint ridges effectively, and they are robust to noise, in addition, the extraction precision of this algorithm is also better than the conventional approaches.

关键词： fingerprint identification feature extraction Bezier curve curvature

Tribological Properties of SiC/Cu Composite at High Temperature

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Journal of Wuhan university of Technology(Materials Science) 2009年第6期24卷 888-891页

作者：范冰冰张锐 zhengzhou Institute of Aeronautical Industry Management School of Materials Science & engineering Zhengzhou University

SiC/Cu composites were prepared by hot pressing. The high temperature tribological properties of the composites were investigated. XRD, SEM techniques were carried out to characterize the samples. It is found that the friction coefficient of SiC/Cu composites increases with the increasing SiC content. The SiC reinforcement particles are worn down other than removed by pulling out during the wear test. Oxidation of Cu debris leads to the smooth contacting surface. Ring crack is formed under the cyclic wear test. The crack propagates through the damaged matrix and along the brittle interface between SiC particles and Cu matrix.

关键词： SiC/Cu composite tribological properties high temperature wear ring crack