检索结果-南通市图书馆

Complex variable method for plane elasticity of icosahedral quasicrystals and elliptic notch problem

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 773-780页

作者： LI LianHe1,2 & FAN TianYou1 1 Department of Physics, beijing Institute of Technology, beijing 100081, china 2 college of Mathematics science, Inner Mongolia normal university, Hohhot 010022, china Department of Physics Beijing Institute of Technology Beijing 100081 China college of Mathematics science Inner Mongolia Normal University Hohhot 010022 China

The complex variable method for the plane elasticity theory of icosahedral quasicrystals is developed. Based on the general solution obtained previously, complex representations of stress and displacement components of phonon and phason fields in the quasicrystals are given. With the help of conformal transformation, an analytic solution for the elliptic notch problem of the material is presented. The solution of the Griffith crack problem can be observed as a special case of the results. The stress intensity factor and energy release rate of the crack are also obtained.

关键词： icosahedral quasicrystals plane elasticity elliptic notch complex variable method

Construction and characterization of the transformation-competent artificial chromosome (TAC) libraries of Leymus multicaulis

在线全文

学校读者我要写书评

暂无评论

science china(Life sciences) 2008年第7期51卷 604-613页

作者： XU YueYu 1,2,3,ZHOU YuLei 4,5 ,SONG LinLin 6 ,ZHANG Yan 3 &ZHAO MaoLin 1 1 beijing Agro-Biotechnology Research Center,beijing Academy of Agriculture and Forestry science,beijing 100097,china 2 Department of Chemistry and Chemical Engineering,Hunan Institute of Engineering,Xiangtan 411104,china 3.college of Life science,Capital normal university,beijing 100037,china 4 college of Life science,Zhongkai university of Agriculture and Technology,Guangzhou 510225,china 5 college of Grassland science,Gansu Agricultural university,Lanzhou 730070,china 6 Department of Biology,Henan Institute of science and Technology,Xinxiang 453003,china 1. beijing Agro-Biotechnology Research Center Beijing Academy of Agriculture and Forestry Science Beijing 100097 China 2. Department of Chemistry and Chemical Engineering Hunan Institute of Engineering Xiangtan 411104 China 3. college of Life science Capital Normal University Beijing 100037 China 4. college of Life science Zhongkai University of Agriculture and Technology Guangzhou 510225 China 5. college of Grassland science Gansu Agricultural University Lanzhou 730070 China 6. Department of Biology Henan Institute of Science and Technology Xinxiang 453003 China

Transformation-competent artificial chromosome system is able to clone and transfer genes efficiently in *** order to clone genes highly tolerant to barley yellow dwarf virus(BYDV),Aphids,drought and salt from Leymus multicaulis,the two TAC genomic libraries I and II were constructed in vector pYLTAC17 and pYLTAC747H/sacB,which contain about 165000 and 236000 recombinant clones *** genome coverage of the two libraries was totally estimated to be about 3―5 haploid genome equivalents,as size selection of genomic DNA fragments was approximately from 9 to 300 *** of the genomic libraries were collected as bulked pools each containing 500 clones or so,stored in twelve 96-deep-well plates and then were gridding in triplicate onto a high-density colony hybridization filter with a 3×3 pattern using a GeneTAC?G3 arraying robot after being transferred manually into three 384-well *** 2501 and 2890 clones of Library in pYLTAC17 and in pYLTAC747H/sacB were stored individually in fourteen 384-well plates and then were automatically gridding in duplicate onto a high-density colony hybridization filter with a 6×6 pattern after a replication of *** positive clones were detected by using the probe glutahione reductase gene of *** libraries constructed here can be used to isolate genomic clones containing target genes,and to carry out genome walking for positional *** the target TAC clones were isolated,they could be immediately transferred into plant genomes with the Agrobacterium system.

关键词： Leymus multicaulis megabase-size DNA transformation-competent artificial chromosome(TAC) genomic library

Effect of surfactants on the structure and photoelectric properties of ITO films by sol-gel method

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第2期29卷 143-148页

作者： LIU Jiaxiang, WU Da, ZHANG Nan, and WANG Yue college of Materials science and Engineering, beijing university of Chemical Technology, beijing 100029, china college of Materials science and Engineering Beijing University of Chemical Technology

The Indium tin oxide（ITO） thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent *** obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol（PEG） were added to the ITO precursor *** influences of surfactants on the structural and photoelectric properties of ITO film samples were *** patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the（400） *** high transmittance（over 95%） was attributed to the preferred orientation and the grain size expansion of ITO *** showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants *** to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.

关键词： surfactants indium tin oxide films sol-gel structure photoelectricity

Synthesis and characterization of a strong-fluorescent Eu-containing hydrotalcite-like compound

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2010年第6期53卷 1273-1280页

作者： CHEN Hong & ZHANG WenGong Institute of Polymer science,college of Chemistry and Materials science,Fujian normal university,Fuzhou 350007,china 1. Institute of Polymer science College of Chemistry and Materials Science Fujian Normal University Fuzhou 350007 China

A novel strong-fluorescent Eu-containing hydrotalcite-like compound (Eu-HTlc) was synthesized using the coprecipitation method,in which aluminum(III) was partially substituted by Europium (III) in the hydrotalcite-like layers,and thenoyltrifluoroacetone,1,10-phenanthroline were dispersed into the anions in the interlayer *** sample was characterized by XRD,XPS,FT-IR,ICP,TG-DSC,TEM and fluorescence spectra,and its composition and structure were *** results indicated that the sample exhibited a characteristic red light (614.nm).The fluorescent lifetime and fluorescence quantum yield of Eu-HTlc were measured to be respectively 893 -s and 66.44%,higher than those of Eu(III)-thenoyltrifluoroacetone1,10-phenanthroline complex [Eu(TTA)3phen].The result of TG-DSC measurement showed the enhanced thermal stability of Eu-HTlc compared with that of MgAl-LDHs and Eu(TTA)*** excellent photoluminescent property and thermal stability,low contents of rare earth ions and ligands,the Eu-HTlc may become one of the novel fluorescent materials with potential applications.

关键词： hydrotalcite-like compound Europium fluorescence intercalation supramolecule

Quality evaluation for air plasma spray thermal barrier coatings with pulsed thermography

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2011年第4期21卷 301-306页

作者： Shi-bin ZHAO~1,Cun-lin ZHANG~2,Nai-ming WU~3,Hua-ming WANG~1 1.School of Materials science and Engineering,Beihang university,beijing 100191,china 2.Department of Physics,Capital normal university,beijing 100048,china 3.School of Jet Propulsion,Beihang university,beijing 100191,china [a] School of Materials science and Engineering Beihang University Beijing 100191 China [b] Department of Physics Capital Normal University Beijing 100048 China [c] School of Jet Propulsion Beihang University Beijing 100191 China

Pulsed thermography(PT) as a non-contact non-destructive evaluation(NDE) technique was employed to examine as-sprayed air plasma spray(APS) thermal barrier coatings(TBCs) for quality *** and micro-structural characteristics play a vital role in determining the *** this paper,PT logarithmic peak second-derivative method was adopted to measure the thickness of top *** dependent thermal images were used to characterize the microstructure which was confirmed by scanning electron microscope(SEM).The results showed that there was relationship between the temperature distribution of the surface and microstructure change in *** distribution in thermal images and measurement results of thickness were in fairly good agreement with the microstructure *** can be concluded that it was possible to employ these NDE methods as quality evaluation for as-sprayed TBCs.

关键词： thermal barrier coatings(TBCs) non-destructive evaluation(NDE) pulsed thermography microstructure thickness measurement

Weighted weak type estimates for commutators of the Marcinkiewicz integrals

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 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 1. Department of Mathematics Beijing Normal University 100875 Beijing China 2. Department of Information and Computing science Zhejiang Institute of Science and Technology 310033 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.

Multiparty simultaneous quantum identity authentication with secret sharing

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2,WEN QiaoYan3 & ZHANG Xing4,5 1 college of Computer science and Technology,beijing university of Technology,beijing 100022,china 2 State Key Laboratory of Information Security (Graduate university of the Chinese Academy of sciences),beijing 100049,china 3 School of science,beijing university of Posts and Telecommunications,beijing 100876,china 4 Institute of Electronic Technology,Information Engineering university,Zhengzhou 450004,china 5 Trusted Computing Laboratory,beijing university of Technology,beijing 100022,china college of Computer science Technology Beijing University of Technology Beijing 100022 China State Key Laboratory of Information Security [Graduate university of the Chinese Academy of sciences] Beijing 100049 China School of science Beijing University of Posts Telecommunications Beijing 100876 China Institute of Electronic Technology Information Engineering University Zhengzhou 450004 China Trusted Computing Laboratory Beijing University of Technology Beijing 100022 China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography

Spatio-temporal pattern analysis of single-trial EEG signals recorded during visual object recognition

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第12期54卷 2519-2527页

作者： WANG ChangMing 1 , HU XiaoPing 3 , YAO Li 1,2 , XIONG Shi 2 & ZHANG JiaCai 2 1 National Key Laboratory of Cognitive Neuroscience and Learning, beijing normal university, beijing 100875, china 2 college of Information science and Technology, beijing normal university, beijing 100875, china 3 Biomedical Imaging Technology Center, Emory university/Georgia Institute of Technology, Atlanta 30322, USA 1. National Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing 100875 China3. Biomedical Imaging Technology Center Emory University/Georgia Institute of Technology Atlanta 30322 USA2. College of Information Science and Technology Beijing Normal University Beijing 100875 China

Object discrimination is a fundamental cognitive function for human brains. In this study, we utilized an analysis approach for single-trial electroencephalography (EEG) to analyze the spatio-temporal activation patterns of visual objects processing in human brains, and attempted to apply it to discriminate different visual objects. The spatial patterns were respectively extracted from scalp EEG and the reconstructed cortical sources, while the experiment participants were perceiving 4 different categories of visual objects (faces, buildings, cats and cars). By classifying the patterns extracted from single-trial EEG, the presented visual objects could be discriminated by a computer, and the classification accuracies may provide a quantitative index to evaluate the spatial differences of the brain activations related to different visual objects. Our results demonstrated that the spatial patterns on both the scalp and the sources levels resulted in higher classification accuracies than chance rate. We also examined the classification results using temporally non-overlapping time intervals of different event-related potential (ERP) components. The temporal changes of classification accuracies may reflect the temporal distribution of the discriminative information in the EEG responses. The present pattern extraction and classification methods may compose a computational model for single-trial EEG data analysis in investigations of the spatio-temporal activation patterns for object recognition. These spatio-temporal patterns in EEG may be useful to identifying the discriminative spatial areas and time stages to improve the accuracies and efficiencies of object discrimination. In addition, investigating and utilizing humans'cognitive mechanisms of object recognition may improve computers' processing efficiency of visual information.

关键词： EEG spatio-temporal pattern object recognition single-trial analysis visual information processing

The study on Sanmenxia annual flow forecasting in the Yellow River with mix regression 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(Technological sciences) 2004年第z1期47卷 118-126页

作者： JIANG Xiaohui1, LIU Changming1,2, WANG Yu3 & WANG Hongrui1 1. beijing normal university, beijing 100875, china 2. Institute of Geographic science and Natural resources, Chinese Academy of sciences, beijing 100101, china 3. Reconnaissance, Planning, Design and Research Institute, YRCC, Zhengzhou 450003, china beijing normal Univ Beijing 100875 Peoples R China Chinese Acad Sci Inst Geog Sci & Nat Resources Beijing 100101 Peoples R China YRCC Reconnaissance Planning Design & Res Inst Zhengzhou 450003 Peoples R China

This paper established mix regression model for simulating annual flow, in which annual runoff is auto-regression factor, precipitation, air temperature and water consumption are regression factors; we adopted 9 hypothesis climate change schemes to forecast the change of annual flow of Sanmenxia Station. The results show : (1) When temperature is steady, the average annual runoff will increase by 8.3% if precipitation increases by 10%; when precipitation decreases by 10%, the average annual runoff will decrease by 8.2%; when precipitation is steady, the average annual runoff will decrease by 2.4% if temperature increases 1℃; if temperature decreases 1℃, runoff will increase by 1.2%. The mix regression model can well simulate annual runoff. (2) As to 9 different temperature and precipitation scenarios, scenario 9 is the most adverse to the runoff of Sanmenxia Station of Yellow River; i.e. temperature increases 1℃ and precipitation decreases by 10%. Under this condition, the simulated average annual runoff decreases by 10.8%. On the contrary, scenario 1 is the best to the enhancement of runoff; i.e. when temperature decreases 1 ℃ precipitation will increase by 10%, which will make the annual runoff of Sanmenxia increase by 10.6%.

关键词： forecast annual flow, mix regression model, Sanmenxia Station