检索结果-南通市图书馆

PHASE STRUCTURE AND PROPERTIES OF EPOXY RESIN MODIFIED BY POLYSILOXANE BEARING PENDANT AMINO GROUPS

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer science 2000年第2期18卷 133-138页

作者： Bing Zhang Xiang-luan Liu Ying Huang Center of Molecular sciences, Institute of Chemistry, chinese academy of sciences, Beijing 100080, China chinese acad sci Inst Chem Ctr Mol Sci Beijing 100080 Peoples R China

Polysiloxane-modified epoxy resins were prepared through the reaction of epoxy resin with polydimethylsiloxanes bearing pendant N-(beta-aminoethyl)-gamma-aminopropyl groups. The morphology and properties of the cured epoxy resins modified by the polysiloxanes were investigated. It was found that the phase structure and properties of the cured epoxy resins depend mainly on the amino group content in the polydimethylsiloxane and the level of the modifier. The change of phase structure in the cured epoxy resin systems was responsible for the dramatic change in their mechanical and surface properties.

关键词： phase structure polysiloxane epoxy resin mechanical property

WEAK CONVERGENCE OF SOME DIRICHLET SERIES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica scientia 2001年第4期21卷 433-439页

作者：丁夏畦罗佩珠 chinese acad sci Inst Appl Math Acad Math & Syst Sci Beijing 100080 Peoples R China

This paper treats Dirichlet series from the point of view developed in [1],[2]. Especially it is found that the kernal function is closely related with the Riemann Zeta-function.

关键词： weak Dirichlet series zeta-function

HYDROPHOBICITY OF CONTAMINATED SILICONE RUBBER SURFACES

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer science 2002年第6期20卷 559-564页

作者： Zhi-min Zheng Cai-hong Xu Jian Jiang Chang-yu Ren Wei Gao Ze-min Xie Center for Molecular science, Institute of Chemistry, chinese academy of sciences, Beijing 100080, China chinese acad sci Inst Chem Ctr Mol Sci Beijing 100080 Peoples R China

Silicone rubber (SIR) shows superior performance when used outdoors, but its surface can be transformed from inherently hydrophobic to hydrophilic by the adsorption of contaminants. Al(OH)(3), Al2O3, quartz powder and active carbon were selected as authentic contaminants. Hydrophobicity of the surface was determined using contact angle measurement. The results indicate that the adsorbability of the contaminants can strongly affect the hydrophobicity of contaminated SIR surface. The increasing rate of contact angle of specimens contaminated by Al(OH)(3) was much faster than that by Al2O3 and quartz due to the adsorption of migrated low molecular weight (LMW) polydimethylsiloxanes. Specimens contaminated by active carbon could achieve surface hydrophobicity within 15 min because active carbon has high adsorbability. Surfaces of contaminated ultrapure SIR, polytetrafluoroethylene (PTFE) and glass remain hydrophilic because they contain no mobile LMW components. The addition of oligomeric polydimethylsiloxanes has little effect on the hydrophobicity of contaminants covered on SIR surface.

关键词： hydrophobicity silicone rubber contact angle contamination

Seasonal variations and environmental control of water use efficiency in subtropical plantation

在线全文

学校读者我要写书评

暂无评论

science China Earth sciences 2006年第S2期49卷 119-126页

作者： SONG Xia, YU Guirui, LIU Yunfen, SUN Xiaomin, LIN Yaoming & WEN Xuefa Institute of Geographysic sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, China Graduate University of the chinese academy of sciences, Beijing 100049, China chinese acad sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China Grad Univ Chinese Acad Sci Beijing 100049 Peoples R China

To understand the seasonal variations of water use efficiency (WUE) of coniferous plantation in the subtropical monsoon area, the experiment was conducted in 2003 and 2004 which presented two distinguished climatic conditions (severe summer drought in 2003 and normal climatic condition in 2004). The water stress influenced WUE greatly, which caused a special seasonal WUE pattern. WUE reached the minimum in summer drought and the maximum in winter, which was contrary to the variation of gross primary production (GPP) and canopy evaporation (Fw). In winter, GPP and Fw increased along with the increasing of air temperature and vapor pressure deficit (VPD), with the similar increasing rate. However, in drought summer, there was an adverse trend among GPP/Fw and air temperature and VPD, and the decreasing rate of GPP was far larger than that of Fw. In summer, the conservation of WUE was changed because of the environmental factors, resulting in the decreasing WUE. The photosynthesis and transpiration of vegetation were mainly controlled by the environmental factors in winter, and the impact of stomatal regulation was relatively weak. In summer, Fw was mainly controlled by the stomatal closure and GPP by both environmental factors and stomatal closure.

关键词： water use efficiency gross primary production canopy evapotransplratlon canopy conductance eddy covariance.

ON THE LIFE OF SPHERE ROLLER

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica scientia 1991年第3期11卷 308-316页

作者：成平施沛德朱力行魏刚 chinese acad sci INST SYST SCIBEIJINGPEOPLES R CHINA chinese acad sci INST APPL MATHBEIJINGPEOPLES R CHINA

In this paper for the life of sphere roller, we derive its limit behavior and by simulation present empirical formulas of its mean, variance and distribution.

关键词： ON THE LIFE OF SPHERE ROLLER

Impacts of ozone on the biomass and yield of rice in open top chambers

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2001年第2期13卷 233-236页

作者： Jin, MB Feng, ZW Zhang, FZ chinese acad sci Ecoenvironm Sci Res Ctr Beijing 10085 Peoples R China

The impacts of different 03 concentration on the biomass and yield of rice were studied by using OTC-1 open-top chambers. Experimental treatments included the activated charcoal-filtered air. (CFA), 50 nl/L (CF50), 100 nl/L ( CF100) and 200 nl/L (CF200) concentrations of O-3. The O-3 treatments significantly decreased the total biomass per plant. The. elevated O-3 exposure resulted in a more decrease in the root growth than in the shoot growth. Assessments of yield characteristics at the final harvest revealed an O-3-induced decrease in the number of grains per plant, resulting from fewer ears per plant, fewer grains per ear and more unfilled grains per ear. The 1000 grain dry weight and the harvest index (HI) were not changed significantly under 50 nl/L or 100 nl/L O-3 exposure, but reduced by 17.0% and 4.8% by 200nl/L O-3 treatment, respectively. Compared to the CFA treatment, CF50, CF100 and CF200 treatments caused a 8.2%, 26.1%, 49.1% decrease of the grain yield per plant, and a 14.2%, 31.7%, 51.7% decrease of the total biomass per plant, respectively. Linear regression showed that the 7h - daily mean O-3 concentration exposure for 3 months ( July-September) and AOT40 ( cunulative exposure accumulation over threshold 40 nl/L) were well correlated with the relative grain yield. A yield loss of 10% was estimated to be at 46.9 nl/L O-3 for 7h-daily mean O-3 concentration exposure or at 12930nl/(L(.)h) O-3 for AOT40.

关键词： open-top chambers ozone rice biomass yield

Discovery of immune related factors in Fenneropenaeus chinensis by annotation of ESTs

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2004年第1期14卷 48-55页

作者： SHEN Yaoqing 1,2 , XIANG Jianhai 1*, WANG Bing 1,2 , LI Fuhua 1 and TONG Wei 3(1. Experimental Marine Biology Laboratory, Institute of Oceanology, chinese academy of sciences, Qingdao 266071,China 2. Graduate School of the chinese academy of sciences, Beijing 100039, China 3. Genomics & Bioinformatics Institute, chinese academy of sciences, Beijing 101300, China) chinese acad sci Inst Oceanol Expt Marine Biol Lab Qingdao 266071 Peoples R China chinese acad sci Grad Sch Beijing 100039 Peoples R China chinese acad sci Geonom & Bioinformat Inst Beijing 101300 Peoples R China

A total of 10446 expressed sequence tags (ESTs) are obtained by a large scale sequencing of a cDNA library from cephalothorax of adult Fenneropenaeus chinensis . An EST analysis platform was built up based on local computers and bioinformatic techniques were used to annotate these ESTs in order to promptly find possible functional genes, especially for immune related factors. About 4% of the ESTs show similarity to the coding sequences of such factors, including lectin, serine protease, serpin, lysozyme, etc. These ESTs provide a partial profile of the immune system in F. chinensis and useful information for further study on these genes.

关键词： Fenneropenaeus chinensis bioinformatics ESTs immune factors

A Possible Multi-stranded DNA Induced by Acid Denaturation-renaturation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Chemical Letters 1997年第1期8卷 49-52页

作者： Li, JW Tian, F Wang, C Bai, CL Cao, EH chinese acad sci INST CHEMBEIJING 100080PEOPLES R CHINA chinese acad sci INST BIOPHYSBEIJING 100080PEOPLES R CHINA

lambda-DNA Hind III was denatured by HCl, renatured by NaOH, and digested by DNase I sequentially. The produced mixture was separated with Sephadex G200 column, and the chromatograph showed a very weak peak of one component resistant to the digestion of DNase I. The results of AFM studies on this component indicated that an unusual form of DNA was present, with the height 13 times that of double-stranded DNA. By comparison with known results, it is suggested that this is a multi-stranded DNA other than simple supercoils.

关键词： DNA A Possible Multi-stranded DNA Induced by Acid Denaturation-renaturation

PREPARATION OF Fe_3O_4/PSt MAGNETIC PARTICLES IN THE PRESENCE OF MAGNETIC FLUID IN ETHANOL/WATER MIXTURE

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer science 1999年第2期17卷 129-134页

作者： Xiao-bin Ding Zong-hua Sun Guo-xiang Wan Ying-yan Jiang Chengdu Institute of Organic Chemistry, Chinesc academy of sciences, Chengdu 610041, China Institute of Chemistry, chinese academy of sciences, Beijing 100080, China chinese acad sci Chengdu Inst Organ Chem Chengdu 610041 Peoples R China chinese acad sci Inst Chem Beijing 100080 Peoples R China

Fe_3O_4/Polystyrene(PSt) magnetic particles with core/shell structure have been prepared in thepresence of Fe_3O_4 magnetic fluid in ethanol/water medium by dispersion polymeriation of styrene. A Fe_3O_4particle formation mechanism was proposed. According to this mechanism, the size of particle nuclei isdetermined by the extent of aggregation of Fe_3O_4 /oligomer. Magnetic particles with diameter ranging from 5to 200 μm were prepared under different reaction conditions. Some polymerization parameters such as theconcentration of monomer, stabilizer, initiator, and ethanol which affect particle size and size distribution arediscussed and their effect on particle formation are explained by the proposed mechanism.

关键词： Fe_3O_4 magnetic fluid Magnetic particle Polystyrene Polymerization Mechanism