检索结果-南通市图书馆

中国环境科学 1990年第3期10卷 224-228页

作者：金秀华 cheu.,yy

应用电感耦合等离子体质谱测定环境生物...

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中华预防医学杂志 1990年第5期24卷 294-295页

作者：金秀华 cheu.,yy 132011，吉林市，吉林省卫生防病中心英国地质研究所

电感耦合等离子体质谱(ICP-MS)是无机分析领域中的新技术[Houk Rs,et *** Chem1980;52:2283],具有谱线简单、灵敏度高、快速,并可对1份样品同时进行多元素定性、定

关键词： ICP-MS 环境生物样品微量元素

On the Expressive Power of Logics on Constraint Databases with Complex Objects

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2019年第4期34卷 795-817页

作者： Hong-cheu.Liu Jixue Liu School of Information Technology and Mathematical Sciences University of South AustraliaAdelaide 5095Australia

We extend the constraint data model to allow complex objects and study the expressive power of various query languages over this sort of constraint *** tools we use come in the form of collapse results which are well established in the context of first-order *** show that the natural-active collapse with a condition and the activegeneric collapse carry over to the second-order logic for structures with o-minimality property and any signature in the complex value *** expressiveness results for more powerful logics including monadic second-order logic,monadic second-order logic with fix-point operators,and fragments of second-order logic are investigated in the *** discuss the data complexity for second-order logics over constraint *** main results are that the complexity upper bounds for three theories,MSO+(LIN),MSO+(POLY),and Inflationary DATALOGact^cv(SC,M)without powerset operator are∪iΣi^NC1,NCH=∪iΣi^NC,and AC^0/poly,*** also consider the problem of query closure property in the context of embedded finite models and constraint databases with complex objects and the issue of how to determine safe constraint queries.

关键词： constraint database monadic second-order logic natural-active collapse Ramsey property o-minimality structure

用带多个排出孔的长岩心渗透率仪进行基岩...

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

油气田开发工程译丛 1992年第12期 22-26页

作者： cheu.,SK 张宏祥

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

酸液对砾石和支撑剂的影响

油气田开发工程译丛 1989年第7期 27-30页

作者： cheu.,SK 冯耀忠

用多接头长岩芯渗透率仪进行基岩酸化处理研究产生新结果

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

世界石油科学 1995年第4期 65-69页

作者： cheu.,SK 黄贞琴

以往的大多数酸处理研究通常使用长度小于３英寸的短岩芯，实验中也只是监测岩芯整体的渗透率变化。这对了解酸化过程是有局限的。要了解深部基岩酸化，用长岩芯进行流动试验是必要的。本文提出：在一定条件下含ＨＦ的酸穿透深度大于１... 详细信息

以往的大多数酸处理研究通常使用长度小于３英寸的短岩芯，实验中也只是监测岩芯整体的渗透率变化。这对了解酸化过程是有局限的。要了解深部基岩酸化，用长岩芯进行流动试验是必要的。本文提出：在一定条件下含ＨＦ的酸穿透深度大于１２英寸，一些缓速酸能产生深部伤害，且氢氟酸不能防止水敏性伤害。结果表明：基于短岩芯试验得出的结论对我们有可能产生错误的指导，而用多插头长岩芯渗透率仪进行酸化处理研究是必要的。

关键词：岩芯长岩芯渗透率仪油层酸化

人工或自然感染PRV猪的即刻早期蛋白的体液免疫应答

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

国外兽医学（畜禽传染病） 1991年第2期11卷 29-31页

作者： cheu.,AK 顾有方

用多级长岩心渗透率测量仪研究基质酸化增产措施获得新结果

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

江汉石油学院情报 1992年第4期 27-33页

作者： cheu.,SK 张光明

H-Bonded Liquid Crystalline Polymer Network Materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2001年第Z1期17卷 89-90页

作者： LIN Hong-cheu Department of Materials Science and Engineering National Chiao Tung University Institute of Chemistry Academia Sinica Institute of Chemistry Academia Sinica

Side-chain copolymers, poly(mOBA-co-mStilb)s, composed of proton acceptors (stilbazoles) and proton donors (benzoic acids) connected to polyacrylate backbone with different methylene spacer lengths (m = 6 and 10) were prepared in different donor/acceptor molar ratios. The H-bonded copolymeric networks were formed once they were synthesized, and showed more homogenous phase than the physical-blended supramolecular networks consisting of donor and acceptor homopolymers, i.e.H-bonded blends of PmOBA and PmStilb. In order to compare the effects of the backbone connection of these H-bonded copolymers and blends, we also built monomer-monomer and polymer-monomer H-bonded complexes of similar structures (shown in Fig. 1). DSC, POM, and powder XRD studies reveal that the copolymers (m = 10)with mole fractions of benzoic acids between 0.33-0.83 show the smectic A (SMA) phase with layer spacing values between 42.22A-50.47A (increases with higher H-bonded crosslinking density between benzoic acids and stilbazoles), while for m = 6, liquid crystalline behavior still can be observed at 0.89 molar fraction of benzoic acids. However, on the basis of powder XRD study it is found that the d spacing values of H-bonded copolymers with m = 6 in the SmA phase increase with higher molar ratios of benzoic acids, which is agreed with the formation of microphase separation due to the hydrogen bonds of benzoic acids connected themselves from the same backbone. The isotropization temperatures of the H-bonded copolymers and blends increase as the molar ratios of benzoic acids increase, while the higher crosslinking density of the H-bonded copolymeric networks and blends can stabilize the liquid crystalline phase.

关键词： Polymer Network benzoic acids crosslinking density supramolecular networks microphase separation powder XRD crystalline behavior similar structures crystalline phase molar fraction hydrogen bonds

New mesomorphic benzothiazol derivatives: Synthesis and characterization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2013年第10期24卷 926-928页

作者： Teck-Ming Koh Sie-Tiong Ha Guan-Yeow Yeap Hong-cheu.Lin Faculty of Engineering & Science Universiti Tunku Abdul RahmanJln Genting KlangSetapak Faculty of Science Universiti Tunku Abdul RahmanJln Universiti Centre for Biodiversity Research Universiti Tunku Abdul RahmanJln Universiti Liquid Crystal Research Laboratory School of Chemical SciencesUniversiti Sains Malaysia Department of Materials Science & Engineering National Chiao Tung University

In this paper, the synthesis of new mesomorphic benzothiazolyl derivatives, 6-ethoxy-2-[4-（4- alkyloxybenzoyloxy）benzylidenamino]benzothiazoles, is presented. The structures of the title compounds were elucidated using spectroscopic techniques, such as FT-IR, NMR （1H and 13C）, elemental analysis and El-MS. The mesomorphic behaviours of these compounds were determined by differential scanning calorimetric and polarizing optical microscopic techniques. Compounds exhibited nematic and tilted smectic phases upon heating from crystal phase. An obvious odd-even effect was observed in this homologous series.

关键词： Benzothiazole Nematic Smectic C Mesomorphic