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1521篇 您的检索式:作者名="P. R. China"
    题名 作者 年代 出处 被引量
1S-rough sets and knowledge separation显示文摘The conceptions of the knowledge screen generated by S-rough sets are given: f- screen and - screen , and then puts forward - filter theorem, - filter theorem of knowledge. At last, the applications of knowledge separation are given according to - screen and - screen.Shi Kaiquan 1,21. School of Mathematics and System Sciences, Liaocheng University, Liaocheng 252059, P. R. China 2. School of Mathematics and System Sciences, Shandong University, Jinan 250100, P. R. China 2005Journal of Systems Engineering and Electronics2005,16,2:104
2L^p-Boundedness of Marcinkiewicz Integrals with Hardy Space Function KernelsYong Ding Department of Mathematics, Beijing Normal University, Beijing 100875, P. R. China Dashan Fan Department of Mathematics, Anhui University and University of Wisconsin-Milwaukee. MW 53201 USA Yibiao Pan Department of Mathematics, University of Pittsburgh. Pittsburgh. Pennsylvania 15260. USA 2000Acta Mathematica Sinica,English Series2000,16,4:88
3Mobius Isoparametric Hypersurfaces in S^(n+1) with Two Distinct Principal CurvaturesHai Zhong LI Department of Mathematics, Tsinghua University. Beijing 100084. P. R. China Hui Li LIU Department of Mathematics, Northeastern University. Shenyang 110000. P. R. China Chang Ping WANG Key Laboratory of Pure and Applied Mathematics, School of Mathematical Sciences. Peking University, Beijing 100871, P. R. China Guo Song ZHAO Department of Mathematics, Sichuan University, Chengdu 610064. P. R. China 2002Acta Mathematica Sinica,English Series2002,18,3:53
4The Constrained Solutions of Two Matrix EquationsAn Ping LIAO Zhong Zhi BAI Department of Mathematics. Hunan University. Changshu, 410082. P. R. China Department of Mathematics and Information Science, Changsha University, Changsha 410003. P. R. China Academy of Mathematics and System. Sciences. Chinese Academy of Sciences. Beijing 100080. P. R. China State Key Laboratory of Scientific/Engineering Computing. Chinese Academy of Sciences. Institute of Computational Mathematics and Scientific/Engineering Computing. Academy of Mathematics and System Sciences. Chinese Academy of Sciences. P. O. Box 2719. Beijing 100080. P. R. China 2002Acta Mathematica Sinica,English Series2002,18,4:40
5Application and study in aluminum melt degassing technologies显示文摘The classification, characteristics and current situation of aluminum melt hydrogen-removal methods and technologies have been summarized. The latest studies and research results of aluminum melt degassing technology have been summed up. The tendency and prospect of aluminum degassing technology was discussed.~*H. J. Ni~(1,2), M. Y. Huang~1, Y. Zhu~1, P. Liao~1, R. Z. WU~2, B. D. Sun~2(1. Department of Mechanical Engineering, Nantong Institute of Technology, Nantong 226007, Jingsu, P. R. China 2. School of Material Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, P. R. China) 2004China Foundry2004,1,S1:27
6Central Limit Theorems for Asymptotically Negatively Associated Random FieldsLixin Zhang Department of Mathematics, Zhejiang University. Xixi Campus. Hangzhou 310028. P. R. China 2000Acta Mathematica Sinica,English Series2000,16,4:25
7Mesozoic basin evolution and tectonic mechanism in Yanshan, China显示文摘The Mesozoic basins in Yanshan, China underwent several important tectonic transformations, including changes from a pre-Late Triassic marginal cratonic basin to a Late Triassic-Late Jurassic flexural basin and then to a late Late Jurassic-Early Cretaceous rift basin. In response to two violent intraplate deformation at Late Triassic and Late Jurassic, coarse fluvial depositional systems in Xingshikou and Tuchengzi Formations were deposited in front of thrust belts. Controlled by transform and extension faulting, fan deltas and lacustrine systems were deposited in Early Cretaceous basins. The composition of clastic debris in Late Triassic and Late Jurassic flexural basins respectively represents unroofing processes from Proterozoic to Archean and from early deposited, overlying pyroclastic rocks to basement rocks in provenance areas. Restored protobasins were gradually migrated toward nearly NEE to EW-trending from Early Jurassic to early Late Jurassic. The Early Cretaceous basins with a NNE-trending crossed over early-formed basins. The Early-Late Jurassic and Early Cretaceous basins were respectively controlled by different tectonic mechanisms.LIU Shaofeng1,2, LI Zhong3 & ZHANG Jinfang4 1. Key Laboratory of Lithospheric Tectonics, Deep-Level Process and Explovation, Ministry of Education of P. R. China, Beijing 100083, China 2. School of Geosciences and Resources, China University of Geosciences, Beijing 100083, China 3. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 4. Institute of Software, Chinese Academy of Science, Beijing 100080, China 2004Science China Earth Sciences2004,47,z2:24
8Super-hydrophobic characteristics of butterfly wing surface显示文摘Many biological surface are hydrophobic because of their complicated composition and surface microstructure. Eleven species (four families) of butterflies were selected to study their micro-, nano-structure and super-hydrophobic characteristic by means of Confocal Light Microscopy, Scanning Electron Microscopy and Contact Angle Measurement. The contact an- gles of water droplets on the butterfly wing surface were consistently measured to be about 150 ? and 100 ? with and without the squamas, respectively. The dust on the surface can be easily cleaned by moving spherical droplets when the inclining angle is larger than 3 ?. It can be concluded that the butterfly wing surface possess a super-hydrophobic, water-repellent, self-cleaning, or “Lotus-effect”characteristic. The contact angle measurement of water droplets on the wing surface with and without the squamas showed that the water-repellent characteristic is a consequence of the microstructure of the squamas. Each water droplet (diameter 2 mm) can cover about 700 squamas with a size of 40 m×80 m of each squama. The regular riblets with a width of 1000 nm to 1500 nm are clearly observed on each single squama. Such nanostructure should play a very important role in their super-hydrophobic and self-cleaning characteristic.CONG Qian, CHEN Guang-hua, FANGYan , REN Lu-quan Key Laboratory for Terrain-Machine Bionics Engineering (Ministry of Education, China), Jilin University, Changchun, 130022, P. R. China 1 2004Journal of Bionic Engineering2004,1,4:24
9Prognosis of 980 patients with gastric cancer after surgical resection显示文摘Background and Objective: Although surgery is the only possible means to cure gastric cancer, the prognosis is often discrepant. The American Joint Committee on Cancer/International Union against Cancer (AJCC/UICC) published the TNM classification of Malignant Tumors (seventh edition) for gastric cancer recently. This study aimed to use this new edition staging system to investigate the prognostic factors for gastric cancer. Methods: The clinicopathologic data of 980 patients with gastric cancer treated by surgical resection in our hospital between January 2000 and December 2006 were analyzed retrospectively. The overall survival rate was determined by using Kaplan-Meier method and log-rank test was used to determine significance. The prognosis was analyzed using univariate analysis and multivariate analysis with the Cox proportional hazards model. The 6th and 7th edition AJCC/UICC TNM staging systems were used to compare the survival outcomes for the cohort of patients. Results: The overall 1-, 3-, 5-year survival rates for the whole group were 82.5%, 58.7%, and 52.6%. The 5-year survival rates for patients with pTNM stage I, II, III, and IV disease classified by the 7th edition staging system were 93.2%, 72.4%, 39.1%, and 5.2%, respectively. In both univariate analysis and Cox multivariate analysis, age, tumor site, tumor size, histological type, resection type, radical resection, lymphatic/venous invasion, depth of invasion, nodal status, metastasis, retrieved lymph nodes, metastatic lymph node ratio, and adjuvant chemotherapy were prognostic factors with these patients. Conclusion: Compared with the 6th edition system, the new edition of TNM staging system for gastric cancer can accurately predict the survival after operation.Wei Wang1,2, Yuan-Fang Li1,2, Xiao-Wei Sun1,2, Ying-Bo Chen1,2, Wei Li1,2, Da-Zhi Xu1,2, Xuan-Xiang Guan1,2, Chun-Yu Huang1,2, You-Qing Zhan1,2, Zhi-Wei Zhou1,2 1 State Key Laboratory of Oncology in South China, Guangzhou, Guangdong 510060, P. R. China 2 Department of Gastric and Pancreatic Surgery, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P. R. China 2010Chinese Journal of Cancer2010,29,11:24
10On the Hyper-Order of Solutions of Some Second-Order Linear Differential EquationsCHEN Zong Xuan Department of Mathematics. Jiangxi Normal University. Nanchang 330027. P. R. China 2002Acta Mathematica Sinica,English Series2002,18,1:24
11Multipliers on Dirichlet Type SpacesPeng Yan HU Department of Mathematics. Normal College of Shenzhen University. Shenzhen. Guangdong 518060. P. R. China Ji Huai SHI Department of Mathematics. University of Science and Technology of China. Hefei. Anhui 230026, P. R. China 2001Acta Mathematica Sinica,English Series2001,17,2:23
12Sliding Mode Controller Design for Position and Speed Control of Flight Simulator Servo System with Large Friction显示文摘Flight simulator is an important device and a typical high-performance position and speed servo system used in the hardware-in-the-loop simulation of flight control system. Friction is the main nonlinear resistance in the flight simulator servo system, especially in a low-speed state. Based on the description of dynamic and static models of a nonlinear Stribeck friction model, this paper puts forward sliding mode controller to overcome the friction, whose stability is proved. Simulation example indicates that the controller can guarantee a high robust performance and have a high precision of position tracking and speed tracking for a flight simulator servo system.Liu Jinkun & Er LianjieAutomatic Control Department, Beijing University of Aeronautics and Astronautics, Beijing 100083, P. R. China 2003Journal of Systems Engineering and Electronics2003,14,3:21
13APPLYING PPE MODEL BASED ON RAGA TO CLASSIFYAND EVALUATE SOIL GRADE显示文摘The research of soil classification and soil grade evaluation is often based on fuzzy theory. So, the traditional method has an inevitable problem about weight matrix which given by some experts, and the final result can be influenced by artificial factors. The essentials of fuzzy synthetically judge is to handle the data of high dimension. That is to reducing the dimension number. The weight matrix in fuzzy theory is corresponding to low dimension projection value of each index. But we can′t define whether the weight matrix given by experts is the best projection value or not. So, the authors apply a new technique of falling dimension named projection pursuit to soil study, through using the improved real coding based accelerating genetic algorithm to optimize the projection direction. Thus, it can transfer multi dimension data into one dimension data, through searching for the optimum projection direction to realize the soil classification and its grade evaluation. The method can avoid the artificial disturbance, and acquire preferably effect. Thus, the paper provides a new method to the research of soil classification and grade evaluation.FU Qiang1,2, LU Tie guang2, FU Hong2(1. College of Hydraulic Power, Sichuan University, Chengdu 610065, P.R.China 2. Northeast Agricultural University, Harbin 150030, P. R. China) 2002Chinese Geographical Science2002,12,2:19
14NONLINEAR STABILITY OF NATURAL RUNGE-KUTTA METHODS FOR NEUTRAL DELAY DIFFERENTIAL EQUATIONS显示文摘This paper first presents the stability analysis of theoretical solutions for a class of nonlinear neutral delay-differential equations (NDDEs). Then the numerical analogous results, of the natural Runge-Kutta (NRK) methods for the same class of nonlinear NDDEs, are given. In particular, it is shown that the (k, l)-algebraic stability of a RK method for ODEs implies the generalized asymptotic stability and the global stability of the induced NRK method.Cheng-jian Zhang(Department of Mathematics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, P. R. China) 2002Journal of Computational Mathematics2002,20,6:18
15An Application of a Mountain Pass TheoremZHOU Huan Song Laboratory of Mathematical Physics. Wuhan Institute of Physics and Mathematics. Chinese Academy of Sciences, P. O. Box 71010, Wuhan 430071. P. R. China 2002Acta Mathematica Sinica,English Series2002,18,1:18
16Peat molecular fossils recording paleoclimatic change and organism replacement显示文摘The occurrence of the dominant C23 n-alkane derived from bryophyte was demonstrated to be related to the cold climate, based on the GC and GC/MS analyses on a 40-cm long peat core, in which this compound exponentially varies in abundance with the depth corresponding to the well-known second Little Ice Age. Both the variation of the chemical components of modern bryophyte resulted from climatic change and the ecological data about the biological growth influenced by climate shed light on the point that the variation of this compound in the peat was related to the cold climate. This was also evidenced by the previously-reported lacustrine data. In addition, the variations of the ratios of ketones/esters and C24 n-alkene/n-alkane (C24:1/024:0) display the trend identical with that of organisms, implicating the replacement between bryophyte and monocotyledon occurring in the peat core.XIE Shucheng & R. P. Evershed1. Faculty of Earth Science, China University of Geosciences, Wuhan 430074, China 2. School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK Correspondence should be addressed to Xie Shucheng (e-mail: scxie@ public.wh.hb.cn) 2001Chinese Science Bulletin2001,46,20:16
17Study on Tribological Properties of Irradiated Crosslinking UHMWPE Nano-Composite显示文摘Ultra High Molecular Weight Polyethylene(UHMWPE)has been widely used as a bearing material for artificial joint replacementover forty years.It is usually crosslinked by gamma rays irradiation before its implantation into human body.In thisstudy,UHMWPE and UHMWPE/nano-hydroxyapatite(n-HA)composite were prepared by vacuum hot-pressing method.Theprepared materials were irradiated by gamma rays in vacuum and molten heat treated in vacuum just after irradiation.The effectof filling n-HA with gamma irradiation on tribological properties of UHMWPE was investigated by using friction and wearexperimental machine(model MM-200)under deionized water lubrication.Micro-morphology of worn surface was observedby metallographic microscope.Contact angle and hardness of the materials were also measured.The results show that contactangle and hardness are changed by filling n-HA and gamma irradiation.Friction coefficient and wear rate under deionized waterlubrication are reduced by filling n-HA.While friction coefficient is increased and wear rate is reduced significantly by gammairradiation.The worn surface of unfilled material is mainly characterized as adhesive wear and abrasive wear,and that of n-HAfilled material is mainly characterized as abrasive wear.After gamma irradiation,the degrees of adhesive and abrasive wear forunfilled material and abrasive wear of n-HA filled material are significantly reduced.Unfilled and filled materials after irradiationare mainly shown as slight fatigue wear.The results indicate that UHMWPE and UHMWPE/n-HA irradiated at the doseof 150 kGy can be used as bearing materials in artificial joints for its excellent wear resistance compared to original UHMWPE.Lei Xiong, Dang-sheng Xiong, Jia-bo JinDepartment of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China 2009Journal of Bionic Engineering2009,6,1:15
18Wave Forces on Submerged Semi-Circular Breakwater and Similar Structures显示文摘—The results of design and experiment of a submerged semi-circular breakwater at the Yangtzeestuary show that the submerged structure will be unsafe when the general empirical wave force formulafor semi-circular breakwater is used in design.Therefore,a new calculation method for the wave forces act-ing on a submerged semi-circular structure is given in this paper,in which the wave force acting on the in-side circumference of semi-circular arch is included,and the phase modification coefficient in the generalempirical formula is adjusted as well.The new wave force calculation method has been verified by the re-sults of seven related physical model tests and adopted in the design of the south esturary jetty of the firststage project of Deep Channel Improvement Project of the Yangtze River Estuary,the total jetty length be-ing 17.5km.XIE Shileng Prof. Senior Engineer, The First Design Institute of Navigation Engineering, Ministry of Communications of China, Tianjin 300222, P. R. China. 1999China Ocean Engineering1999,14,1:15
19Advances in Cotton Breeding for Resistance to Fusarium and Verticillium Wilt in the Last Fifty Years in China显示文摘This review summarizes the main advances in cotton breeding for resistance to fusarium andverticillium wilt in the last fifty years in China. The topics discussed include main achievements, experiences,problems and countermeasures for solving.JIAN Gui-liang, MA Cun, ZHENG Chuan-lin and ZOU Ya-feiInstitute of Plant Protection , Chinese Academy of Agricultural Sciences, Beijing 100094 , P. R. China 2003Agricultural Sciences in China2003,2,3:15
20APPLICATION OF SWAT MODEL IN THE UPSTREAM WATERSHED OF THE LUOHE RIVER显示文摘In the Huanghe (Yellow) River basin,soil erosion is a serious problem,while runoff and sediment yield simulation has not been extensively studied on the basis of GIS (Geographic Information System) and distributed hydrological model. GIS-based SWAT (Soil and Water Assessment Tool) model was used to simulate runoff and sediment in the Huanghe River basin. The objective of this paper is to examine the applicability of SWAT model in a large river basin with high sediment runoff modulus,which could reach 770t/(km2·a). A two-stage 'Brute Force' optimization procedure was used to calibrate the parameters with the observed monthly flow and sediment data from 1992 to 1997,and with input parameters set during the calibration process without any change the model was validated with 1998-1999’s observed data. Coefficient of examination (R2) and Nash-Suttcliffe simulation efficiency (Ens) were used to evaluate model prediction. The evaluation coefficients for simulated flow and sediment,and observed flow and sediment were all above 0.7,which shows that SWAT model could be a useful tool for water resources and soil conservation planning in the Huanghe River basin.ZHANG Xue-song, HAO Fang-hua, CHENG Hong-guang, LI Dao-feng (State Key Laboratory of Water Environment Simulation,Institute of Environmental Sciences, Beijing Normal University,Beijing 100875,P. R. China) 2003Chinese Geographical Science2003,13,4:14
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