检索结果-南通市图书馆

Empirical likelihood confidence regions of the parameters in a partially linear single-index model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第10期48卷 1333-1348页

作者： XUE Liugen~1 & ZHU Lixing~2.1. college of applied {2.,Beijing university of Technology,Beijing 10002.,china 2. Department of Mathematics,Hong Kong Baptist university,Hong Kong,china 1. college of applied {2. Beijing University of Technology 100022 Beijing China 2. Department of Mathematics Hong Kong Baptist University Hong Kong China

In this paper, a partially linear single-index model is investigated, and three empirical log-likelihood ratio statistics for the unknown parameters in the model are suggested. It is proved that the proposed statistics are asymptotically standard chi-square under some suitable conditions, and hence can be used to construct the confidence regions of the parameters. Our methods can also deal with the confidence region construction for the index in the pure single-index model. A simulation study indicates that, in terms of coverage probabilities and average areas of the confidence regions, the proposed methods perform better than the least-squares method.

关键词： partially linear single-index model, empirical likelihood, confidence region, chi-square distribution, coverage probability.

Research on the method for retrieving soil moisture using thermal inertia model

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第5期49卷 539-545页

作者： LIU Zhenhua1 & ZHAO Yingshi2.1. Information college, South china Agricultural {2., Guangzhou 510642. china 2. Graduate {2. of Chinese Academy of sciences, Beijing 100049, china 1. Information college South China Agricultural University Guangzhou 510642 China 2. Graduate university of Chinese Academy of sciences Beijing 100049 China

In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature parameter input instead of input of the surface temperature difference, as well as the surface sensible and latent fluxes are introduced into boundary conditions of thermal conductivity equation. Furthermore, surface soil conductive heat transfer equation of two-layer model is used to solve the soil thermal inertia so that the remote sensing thermal inertia method can be ap- plied to regions with better-covered vegetation, but usually only for the bare areas or worse vegetation covered areas. The model has been tested at several locations in the area of west Inner Mongolia. Comparing the simulation of the new model with the measurements obtained by apparent thermal inertia and by field test, the result shows that the inertia thermal model can be used to estimate soil moisture in more reasonable accuracy.

关键词： thermal model, thermal conductivity equation, soil initial, sensible flux, latent flux, two-layer model.

A pulse radiolysis study on electron affinity of piperonal

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2005年第5期48卷 476-480页

作者： MA Jianhua1, LIN Weizhen2. WANG Wenfeng2.& YAO Side2.1. college of Biology Engineering, Jimei university, Xiamen 36102., {2. 2. Shanghai Institute of applied Physics, Chinese Academy of sciences, Shanghai 2.1800, {2. 1. college of Biology Engineering Jimei University 361021 Xiamen China 2. Shanghai Institute of applied Physics Chinese Academy of Sciences 201800 Shanghai China

The piperonal electron affinity was studied using pulse radiolysis technique. The electron transfer reaction process between piperonal and anthraquinone-2.sulfate was observed in the pH 7 phosphoric acid salt buffer. The transient absorption spectra of electron transfer re-action between piperonal and anthraquinone-2.sulfate were obtained, and the initial proof of the electron transfer between electron donor and acceptor was provided directly. The one-electron reduction potential of piperonal was determined to be ?0.457 V.

关键词： piperonal, pulse radiolysis, one-electron reduction potential.

Synthesis,characterization,properties and crystal structure of heterometallic 1D coordination polymers {[CuLZn·CuLZn(H_2.)]·H_2.}_n

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2006年第4期49卷 338-344页

作者： TAO Ruojie1, LI Fu’an1, ZANG Shuangquan1, CHENG Yanxiang2.& NIU Jingyang1 1. Chemistry and Chemical Engineering college of Henan university, Kaifeng 475001, {2. 2. Changchun Institute of applied Chemistry, Chinese Academy of sciences, Changchun 13002., {2. 1. Chemistry and Chemical Engineering college of Henan university Kaifeng 475001 China 2. Changchun Institute of applied Chemistry Chinese Academy of Sciences Changchun 130022 China

Copper-zinc heterometallic 1D chain coordination polymer has been synthesized and characterized by elemental analysis, and IR spectra etc. The crystal structure was determined by single-crystal X-ray diffraction analyses. The title complex is 1D chain coordination polymer with the chemical formula {[CuLZn·CuLZn(H2.)]·H2.}n, where H4L=N-(2.hydroxybenzamido)-N’-(3-carboxy- lsalicylidene)ethylenediamine. Its structural unit is comprosed of two tetranuclear cycles formed by two dissymmetrical tetranuclear units. These units polymerized each other to form 1D chain coordi- nation polymer.

关键词： copper, zinc, heterometallic coordination polymer, crystal structure.

Existence of solutions for the dynamic equation of ferrimagnets

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第11期17卷 1279-1283页

作者： Zeng Ming1, Guo Boling2.and Cheng Caozong1(1. college of applied {2., Beijing university of Technology, Beijing 10002., china 2. Center for Nonlinear Studies, Institute of applied Physics and Computational Mathematics, Beijing 100088, china) college of applied {2. Beijing University of Technology Beijing 100022 China Center for Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Ferrimagnet is a kind of basic and important multi-sublattice magnet material. It has attracted more and more attention of physicists and mathematicians. Many results of solitons and numerical computations on this topic have appeared. In this article, the dynamic equation for an isotropic ferrimagnet with two non-equivalent sublattices is studied, existence of weak solutions in multi dimension case is proved through the penalized method, the uniqueness and smoothness of the solution in one dimension case are also obtained by the relation between this equation and hyperbolic equation.

关键词： ferrimagnet weak solutions penalized method finite difference method

Biological aspects on the cultures of the entomophthoralean fungus Pandora delphacis grown on broomcorn millets

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2003年第17期48卷 1816-1821页

作者： FENG Mingguang1,2.& LIANG Yong1 1. Institute of Microbiology, college of Life sciences, Zhejiang Univer-sity, Hangzhou 31002., {2. 2. Institute of applied Entomology, college of Agricultural sciences and Biotechnology, Zhejiang university, Hangzhou 31002., {2. Institute of Microbiology College of Life Sciences Zhejiang University Hangzhou 310029 China

A novel method was developed to use glutinous broomcorn millets (Panicum miliaceum L.) as solid substrate to make cultures of the entomophthoralean fungus Pandora delphacis specifically pathogenic to planthoppers, leafhop-pers and aphids. Steamed millets with water content of 45% were inoculated with a liquid culture of P. delphacis at a ratio of 2.% (v/w) and then incubated at 2.℃ and L:D 12.12. The millets cultured for 3—17 d exhibited high potential for co-nidial production. The 5-d-old millet culture sporulated most abundantly, discharging up to 17.12.(1.31) 104 conidia/ millet. The cultures incubated for 7—11 d also had a satis-factory sporulation capability, yielding 13.00—13.90 104 conidia/millet. Compared to 2.32.(0.34) 104 conidia dis-charged from each of Myzus persicae adults killed by P. del-phacis and a ≤60-h duration of sporulation, each of the millets cultured for 5—11 d produced 5.6—7.4 times more conidia with an over doubled duration for conidial discharge (144 h). Among 106 M. persicae adults exposed to the shower of conidia discharged from the cultured millets, a total mor-tality of 69.8% caused by P. delphacis infection was observed within 7 d after exposure, but no death was attributed to the fungal infection in the aphids unexposed. The results indi-cate that the millet cultures of P. delphacis are biologically similar to aphid cadavers killed by the same fungus. Due to the superiority of the cultured millets to the cadavers in sporulation potential and duration, the method for making cultures of P. delphacis on the broomcorn millets is highly recommended for use in study of entomophthoralean fungi for microbial control. This is the first report on the success of the solid culture of Pandora species on cereals.

关键词： entomophthorales Pandora delphacis broomcorn millets solid culture sporulation capability aphid infectivity.

Molecular dynamics simulation of thermal stability of nanocrystalline vanadium

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2006年第4期49卷 400-407页

作者： WEI Mingzhi1, XIAO Shifang1, YUAN Xiaojian2.& HU Wangyu1,2.1. Material Science and Engineering college, Hunan university, Changsha 410082. {2. 2. Department of applied Physics, Hunan university, Changsha 410082. {2. Material Science Engineering college Hunan University Changsha 410082 China Department of applied Physics Hunan University Changsha 410082 China

The microstructure and thermal stability of nanocrystalline vanadium with an average grain size ranging from 2.86 to 7.50 nm are calculated by means of the analytic embedded-atom method and molecular dynamics. The grain boundary and nanocrystal- line grain atoms are differentiated by the common neighbor analysis method. The results indicate that the fraction of grain boundary increases with the grain size decreasing, and the mean energy of atoms is higher than that of coarse crystals. The thermal-stable tem- peratures of nanocrystalline vanadium are determined from the evolution of atomic energy, fraction of grain boundary and radial distribution function. It is shown that the stable tem- perature decreases obviously with the grain size decreasing. In addition the reasons which cause the grain growth of nanocrystalline vanadium are discussed.

关键词： nanocrystalline, embedded-atom method, molecular dynamics, thermal stability.

Extraction of vegetation fraction information from CBERS images based on VBSI vegetation index in Kaixian county

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 712-716页

作者： GAO Zhi-fang1, NIU Hai-peng1, LIU Jin-ping2.1. college of Surveying and Land Information Engineering, Henan Polytechnic university, Jiaozuo 454000, {2. 2. college of Geographic sciences, Chongqing Normal university, Chongqing 400047, {2. [a] college of Surveying and Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China [b] college of Geographic sciences Chongqing Normal University Chongqing 400047 China

Based on the mixed pixel model, the vegetation fraction of Kaixian county, china, was extracted with three free CBERS images. VBSI vegetation index suitable for CBERS images constructed with FCD (forest canopy density) model principle was put forward by ITTO (International Tropical Timber Organization) was used, considering the underestimation of vegetation fraction using NDVI in low mountain-hill region influenced by soils and shadows. And vegetation fraction was divided into five categories from low to high in order to study the special variation of vegetation cover. The results show that the vegetation cover of the region is overall good, with an average of 50%. The area of vegetation fraction below 30% accounts for 11.7% of the entire studied area, mainly concentrates in central eastern Kaixian county, where is the major development zone of cities and towns; that between 30% and 60% accounts for 62.; and that higher than 60% accounts for 2.%, and mostly locates in northern middle-mountain area.

关键词： VBSI vegetation index mixed pixel model FCD model CBERS

A new DNA algorithm to solve graph coloring problem

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2. Meng Ya3 and Meng Dazhi2.1. National Laboratory of Pattern Recognition,Institute of Automation, Chinese Academy of sciences, Beijing 100080, china 2. {2. of applied sciences, Beijing university of Technology, Beijing 10002., china 3. School of Science, Beijing Institute of Technology, Beijing 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China college of applied {2. Beijing University of Technology Beijing 100022 China School of Science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.