检索结果-南通市图书馆

Preparation and Characterization of Sol-gel Derived CH_3SiO_(3/2)-SiO_2 Thick Film

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1998年第6期14卷 523-526页

作者： Bing CAO and Congshan ZHU(Shanghai institute of Optics and Fine Mechanics, chinese academy of sciences, Shanghai 201800, china) Shanghai institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China

A large size CH3SiO3/2-SiO2 self sustained film with the thickness ranging from 5. to 1000 μm was prepared through sol-gel method by adopting CH3Si(OC2H5.3 and Si(OC2H5. as *** this paper, the preparation processes of this thick film are discussed in detail and XRD technique was adopted for the identification of oligomer solution. Also, IR and AFM techniques were used to investigate the film structure and surface morphology

关键词： Preparation and Characterization of Sol-gel Derived CH3SiO MTES CH

Research on a New Process of Preparation for Nano-SiO_2 with High Activity and Mesopores

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第3期20卷 353-356页

作者： Ruijing ZHANG Ke YANG Tianyng XIONG institute of Metal Resarch,chinese academy of sciences,Shenyang 110016, china Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Nano-SiO_2 with high activity and mesopores was prepared through sol-gel synthesis followed by low-temperatureheat treatment and ball milling firstly in our experiments. TEM was performed to measure particle sizes. Nitrogenadsorption experiments were carried out to estimate specific surface area, porous distribution and porous ratio by BETand BJH methods. The content of Si-OH in SiO_2 surface was calculated by analysis of the results of hydrogen-oxygencontent mensuration (HOCM). As a result, appropriate heat treatment system and ball milling time are important topreparation for nano-SiO_2 with high activity and mesopores, which are 5.5. nm particles, 5.6 nm average aperture,85.～93% porous ratio, and 5.%～5.% Si-OH content in surface. Nano-SiO_2 with that structure has high surfaceenergy and activity. This process, which has simple facilities and operation rules, is a new way of preparation fornano-SiO_2 with high activity and mesopores.

关键词： Heat treatment Ball milling Mesopores Nano-SiO_2

Models and methods for precise determination of ionospheric delay using GPS

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2期17卷 187-196页

作者： YUAN Yunbin, HUO Xingliang and OU Jikun ( institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, china Graduate University of chinese A-cademy of sciences, Beijing 100039, china) [a]chinese academy of sciences Institute of Geodesy and Geophysics Wuhan China [b]Graduate University of chinese academy of sciences Beijing China

The basic principles and methods for precisely determining ionospheric delays in GPS observations are introduced and discussed. Various methods and models for fitting ionospheric delays based on GPS are compared and a... 详细信息

关键词： GPS ionospheric delay atmosphere modeling precise GPS positioning.

SOLVING INTEGRAL EQUATIONS WITH LOGARITHMICKERNEL BY USING PERIODIC QUASI-WAVELETSOLVING INTEGRAL EQUATIONS WITH LOGARITHMICKERNEL BY USING PERIODIC QUASI-WAVELET

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2000年第5期18卷 487-512页

作者： Han-lin Chen,Si-long Peng (institute of Mathematics, chinese academy of sciences, Beijing 100080, china) 中科院数学所北京 100080

In solving integral equations with logarithmic kernel which arises from the boundary integral equation reformulation of some boundary value problems for the two dimensional Helmholtz equation, we combine the Galerkin method with Beylkin's ([2]) approach, series of dense and nonsymmetric matrices may appear if we use traditional method. By appealing the so-called periodic quasi-wavelet (PQW in abbr.) ([5.), some of theme matrices become diagonal, therefore we can the a algorithm with only O(K(m)2) arithmetic operations where m is the highest level. The Galerkin approximation has a polynomial rate of convergence.

关键词： Periodic Quasi-Wavelet Integral equation Multiscale.

STUDY OF IMPACT OF ESTABLISHMENT OF A DAM ON LOCAL TIDAL CURRENTS IN KENDONG OIL FIELD

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2004年第3期16卷 356-365页

作者： LIUHao YINBao-shu YUKe-jun YANGDe-zhou XUYan-qing instituteofOceanology ChineseAcademyofSciencesQingdao266071China instituteofOceanology.chineseacademyofsciences Qingdao266071China

In this paper a three-dimensional tidal current model has been used toexamine variations of local fluid field due to establishment of a dam. By imputing ten tides-K_1,O_1, P_1 , Q_1, M_2, S_2, N_2, K_2 , S_a and S_(sa) through the open boundary of the Bohai straitand adopting 5. x 5. horizontal resolution the whole fluid field of the Bohai Sea was firstsimulated. The computed harmonic constants of m_1 and M_2 tides at seventeen observational stationsalong the coast of the Bohai Sea matched the observed values rather well. Taking the calculatednumerical results as open boundary conditions, the local fluid field in the Kendong Oil Field bymeans of 1′ x 1′ horizontal resolution was then investigated. In the course of calculation, finegrids were embedded in coarse grids so as to enhance the computational order. In addition, thelatest water-depth data of the Huanghe Delta coast area were adopted, thus topographic changesbecause of silt sediment in that region wouldn''t affect the computed results. In the end, byanalyzing the relative changes of the fluid field before and after the dam was established, that theeffect on the dynamic environment of the local sea area mainly concentrated on the adjacentpositions north and south of the dam was suggested.

关键词： tidal current harmonic constants open boundary frequency analysis

A one-dimensional heat transfer model of the Antarctic Ice Sheet and modeling of snow temperatures at Dome A, the summit of Antarctic Plateau

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第5期53卷 763-772页

作者： CHEN BaiLian1,3, ZHANG RenHe2, SUN ShuFen1, BIAN LinGen2, XIAO CunDe4,2 & ZHANG TingJun5.1 institute of Atmospheric Physics, chinese academy of sciences, Beijing 100029, china 2 chinese academy of Meteorological {5., Beijing 100081, china 3 Graduate University of chinese academy of sciences, Beijing 100049, china 4 Cold and Arid Regions Environmental and Engineering Research institute, chinese academy of sciences, Lanzhou 730000, china 5.The National Snow and Ice Data Center, University of Colorado, Boulder, CO 80309-0449, USA 1. institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Chinese Academy of Meteorological Sciences Beijing 100081 China4. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China5. The National Snow and Ice Data Center University of Colorado Boulder CO 80309-0449 USA

A vertical one-dimensional numerical model for heat transferring within the near-surface snow layer of the Antarctic Ice Sheet was developed based on simplified parameterizations of associated physical processes for the atmosphere, radiation, and snow/ice systems. Using the meteorological data of an automatic weather station (AWS) at Dome A (80°22′S, 70°22′E), we applied the model to simulate the seasonal temperature variation within a depth of 20 m. Comparison of modeled results with observed snow temperatures at 4 measurement depths (0.1, 1, 3, 10 m) shows good agreement and consistent seasonal variations. The model results reveal the vertical temperature structure within the near-surface snow layer and its seasonal variance with more details than those by limited measurements. Analyses on the model outputs of the surface energy fluxes show that: 1) the surface energy balance at Dome A is characterized by the compensation between negative net radiation and the positive sensible fluxes, and 2) the sensible heat is on average transported from the atmosphere to the snow, and has an evident increase in spring. The results are considered well representative for the highest interior Antarctic Plateau.

关键词： Antarctic Ice Sheet near-surface layer energy transfer numerical model

The cDNA and Genomic DNA Organization of a Novel Toxin SHT-I from Spider Ornithoctonus huwena

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2004年第10期36卷 656-660页

作者： Peng QIAO, Xiao-Pan ZUO, Zhi-Fang CHAI, and Yong-Hua JI* institute of Physiology, Shanghai institutes for Biological sciences, chinese academy of sciences, Graduate School of the chinese academy of sciences, Shanghai 200031,{5. institute of Physiology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

In present study the full-length cDNA of a novel toxin from the venom gland of spider Ornithoctonus huwena, named as SHT-I, has been cloned using the strategy of rapid amplification of cDNA ends, and then the whole genomic sequence of SHT-I (Selenocosmia huwena toxin-I) was determined using sequence-specific primers synthesized based on the acquired 3’ and 5. ends of SHT-I cDNA sequence. It is unexpectedly found that intron was lacking in the genomic sequence of SHT-I. The result might evoke an interesting question whether the gene code of inhibitor cystine-knot peptides from spider venom is distinct from that of those known toxic peptides of scorpion and cone snail.

关键词： Ornithoctonus huwena spider cDNA genomic DNA peptide toxin ICK motif

Biomass estimation and uncertainty analysis based on CBERS-02 CCD camera data and field measurement

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) 2005年第S2期48卷 116-128页

作者： CHEN Liangfu1,2, GAO Yanhua1,3, CHENG Yu1,3, WEI Zheng1,3, XIAO Qing1,4, LIU Qinhuo1, YU Tao1, LIU Qijing5. GU Xingfa1 & TIAN Guoliang1 1. State Key Laboratory of Remote Sensing Science, institute of Remote Sensing Applications, chinese academy of sciences, Beijing 100101, china 2. Geography and Environment College, Jiangxi Normal University, Nanchang 330027, china 3. Graduate University of chinese academy of sciences, Beijing 100039, china 4. Beijing Research institute of Uranium Geology, Beijing 100875. china 5. institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, china 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China 2. Geography and Environment College Jiangxi Normal University 330027 Nanchang China 3. Graduate University of chinese academy of sciences 100039 Beijing China 4. Beijing Research institute of Uranium Geology 100875 Beijing China 5. institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

The study site is located in Qianyanzhou experimental station and the surrounding area. Based on CBERS-02 satellite data and field measurement, we not only discussed the relationship between NDVI and biomass of two species of coniferous plantations, namely, Pinus massoniana Lamb and Pinus elliottii Engelm, but also introduced the biomass models based on NDVI. The comparison between measured biomass in Qianyanzhou and biomass derived from CBERS-02 CCD data showed that it is feasible to estimate biomass based on NDVI. But its limitations cannot be ignored. This kind of model depends on the dominant vegetation species. There are some effect factors in estimating biomass based on NDVI. This paper analyzes these factors based on fine-resolution CBERS-02 CCD data and some conclusions are drawn: In Qianyanzhou, the area with good vegetation coverage, the nonlinearity of NDVI has little influence on scaling-up of NDVI. As a result of surface heterogeneity, scaling-up can cause NDVI within each pixel to change. Because scaling-up can cause pixel attribute to change, the applicability of biomass model is one of the sources of error in estimating biomass.

关键词： NDVI biomass scaling effect scaling-up.

Cloning and characterization of vernalization-related gene (ver203F) cDNA 3'end

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1999年第14期44卷 1289-1294页

作者： YONG Weidong, CHONG Kang , LIANG Tiebing, XU Zhihong , TAN Kehui and ZHU Zhiqing Research Center for Molecular and Developmental biology, institute of Botany, chinese academy of sciences , Beijing 100093, china Shanghai institute of Plant Physiology , chinese academy of sciences , Shanghai 200032, china Corresponding authors Research Center for Molecular and Developmental biology Institute of Botany Chinese Academy of Sciences Beijing China Shanghai institute of Plant Physiology Chinese Academy of Sciences Shanghai China

Based on the cDNA fragment sequence of vernalization-related gene verc203 cloned by differential screening in our lab, the 5.primer has been designed. The cDNA 3′end of ver203 gene (1 197 bp) has been cloned by the RACE method. And it is identified by Northern blotting that its expression is special in vernalization treatment. After comparing the sequence in the nucleotide sequence databases of Genbank, EMBL and DDBJ, the gene has homology with Hordeum vulgare jesmonate-induced protein gene. It is suggested that this gene might be related to the signal transduction mediated by jamonate.

关键词： wheat vernalization-related gene cDNA 3’ end RACE.