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Preparation of polystyrene/silica nanocomposites by radical copolymerization of styrene with silica macromonomer

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Science china Chemistry 2007年第3期50卷 385-391页

作者： OU BaoLi1,2.& LI DuXin2.1 College of Chemistry and Chemical Engineering, Hunan university of Science and technology, Xiangtan 4112.1, {2. 2.state key laboratory of Powder Metallurgy, Central South university, Changsha 410083, {2. 1. College of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan 411201 China 2. state key {2. of Powder Metallurgy Central South University Changsha 410083 China

A two-stage process has been developed to generate the silica-based macromonomer through surface-modification of silica with polymerizable vinyl groups. The silica surfaces were treated with excess 2.4-toluene diisocynate (TDI), after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction with hydroxypropylacrylate (HPA). Thus, polystyrene/silica nanocomposites were prepared by conventional radical copolymerization of styrene with silica macromonomer. The main effecting factors, such as ratios of styrene to the macromonomer, together with polymerization time on the copolymerization were studied in detail. FTIR, DSC and TGA were utilized to characterize the nanocomposites. Experimental results revealed that the silica nanoparticles act as cross-linking points in the polystytene/silica nanocomposites, and the glass transition temperatures of the nanocomposites are higher than that of the corresponding pure polystyrene. The glass transition temperatures of nanocomposites increased with the increasing of silica contents, which were further ascertained by DSC.

关键词： silica nanoparticles surface modification styrene radical copolymerization nanocomposites

Study of Synthesis Identification in Cutting Process with Fuzzy Neural Network

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厦门大学学报（自然科学版） 2002年第S1期41卷 40-41页

作者： LIN Bin, YU Si-yuan, ZHU Hong-tao, ZHU Meng-zhou, LIN Meng-xia (The state Education Ministry key {2. of High Temperature Structure Ceramics and Machining technology of Engineering Ceramics, tianjin university, tianjin 300072, china)

With the development of industrial production modernization, FMS and CIMS will become more and more popularized. For its control system is increasingly modeled, intellectualized and automatized, in order to raise the reliability and stability in the manufacturing process, the comprehensive monitoring and diagnosis aimed at cutting tool wear and chatter become more and more important and get rapid development. The paper tried to discuss of the intellectual status identification method based on acoustics-vibra characteristics of machining process, and propose that the working conditions may be taken as a core, complex fuzzy inference neural network model based on artificial neural network theory, and by using various kinds of modernized signal processing method to abstract enough characteristics parameters which will reflect overall processing status from machining acoustics-vibra signal as information source, to identify different working condition, and provide guarantee for automation and intelligence in machining process. The complex network is composed of NNw and NNs, Each of them is composed of BP model network, NNw is weight network at rule condition, NNs is decision-making network of each status. Y out is final inference result which is to take subordinate degree as weight from NNw, to weight reflecting result from NNs and obtain status inference of monitoring system. In the process of machining, the acoustics-vibor signal were gotten by the acoustimeter and the acceleration piezoelectricity detector, the date is analysed by the signal processing software in time and frequency domain, then form multi feature parameter vector of criterion pattern samples for the different stage of cutting chatter and acoustics-vibra multi feature parameter vector. The vector can give a accurate and comprehensive description for the cutting process, and have the characteristic which are speediness of time domain and veracity of frequency domain. The research works have been pract

关键词： artificial neural network, synthesis identification, fuzzy inference on-line monitoring, acoustics-vibra signal

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HCCI汽油机混合燃烧及放热率计算模型

天津大学学报 2009年第11期42卷 997-1005页

作者：侯圣智谢辉陈韬胡顺堂赵华天津大学内燃机燃烧学国家重点实验室天津300072 天津大学内燃机研究所天津300072

火花辅助点火HCCI燃烧,是介于纯均质压燃着火燃烧以及传统火花点火燃烧这2.燃烧模式之间的一种特殊的燃烧模式.为此,在全可变气门机构HCCI单缸试验发动机上,研究了火花辅助点火SI-HCCI燃烧模式过渡过程的燃烧特征.通过对火花辅助点火对... 详细信息

火花辅助点火HCCI燃烧,是介于纯均质压燃着火燃烧以及传统火花点火燃烧这2.燃烧模式之间的一种特殊的燃烧模式.为此,在全可变气门机构HCCI单缸试验发动机上,研究了火花辅助点火SI-HCCI燃烧模式过渡过程的燃烧特征.通过对火花辅助点火对HCCI燃烧及混合燃烧影响规律的系统分析,提出了产生混合燃烧必须满足的温度条件,建立了由SI向HCCI切换的判断条件计算函数;结合SI函数、HCCI函数和切换条件函数,构建了能够描述混合燃烧过程的燃烧放热率计算模型,为SI-HCCI模式过渡控制策略研究提供了理论依据和技术手段.

关键词： HCCI汽油机混合放热率模式过渡

Advanced fluid-typing methods for NMR logging

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Petroleum Science 2011年第2期8卷 163-169页

作者： Xie Ranhong Xiao Lizhi state key {2. of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China key laboratory of Earth Prospecting and Information {2. China University of Petroleum Beijing 102249 China

In recent years, nuclear magnetic resonance （NMR） has been increasingly used for fluid- typing in well-logging because of the improved generations of NMR logging tools. This paper first discusses the applicable conditions of two one-dimensional NMR methods： the dual TW method and dual TE method. Then, the two-dimensional （T2. D） and （T2. T1） NMR methods are introduced. These different typing methods for hydrocarbon are compared and analyzed by numerical simulation. The results show that the dual TW method is not suitable for identifying a macroporous water layer. The dual TE method is not suitable for typing gas and irreducible water. （T2. T1） method is more effective in typing a gas layer. In an oil-bearing layer of movable water containing big pores, （T2. T1） method can solve the misinterpretation problem in the dual TWmethod between a water layer with big pores and an oil layer. The （T2. T1） method can distinguish irreducible water from oil of a medium viscosity, and the viscosity range of oil becomes wide in contrast with that of the dual TW method. The （T2. D） method is more effective in typing oil and water layers. In a gas layer, when the SNR is higher than a threshold, the （T2. D） method can resolve the overlapping T2.signals of irreducible water and gas that occurs due to the use of the dual TE method. Twodimensional NMR for fluid-typing is an important development of well logging technology.

关键词： NMR logging one-dimensional NMR two-dimensional NMR reservoir evaluation fluidtyping

Highly regio-and stereo-selective copolymerization of CO_2.with racemic propylene oxide catalyzed by unsymmetrical (S,S,S)-salenCo(Ⅲ) complexes

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Science china Chemistry 2010年第8期53卷 1646-1652页

作者： REN WeiMin,ZHANG WenZhen & LU XiaoBing state key {2. of Fine Chemicals Dalian university of technology,Dalian 116012.china 1. state key {2. of Fine Chemicals Dalian University of Technology Dalian 116012 China

A novel unsymmetrical (S,S,S)-salen ligand bearing a derived chiral-BINOL was synthesized by the reaction of the condensation product of (1S,2.)-1,2.diaminocyclohexane mono(hydrogen chloride) with 3-adamanyl-5-tert-butyl-2.hydroxybenzalde-hyde and 3-formoyl-2.hydroxy-2.-alkyloxy-1,1'-binaphthyl,which originated from (S)-1,1'-bi-2.naphthol via a four-step *** cobalt complexes of this ligand,in conjunction with a nucleophilic cocatalyst,exhibited excellent activity in catalyzing asymmetric,regio-and stereo-selective copolymerization of CO2.and racemic propylene *** highest record of kinetic resolution coefficient (Krel) was obtained with the use of binary catalyst system consisting of (S,S,S)-salenCo(III) complex 1c and bulky bis(triphenylphosphine)-iminium chloride (PPNCl).The resulting poly(propylene carbonate)s have more than 99% carbonate linkages and more than 98% head-to-tail content.

关键词： carbon dioxide propylene oxide polycarbonate stereochemistry asymmetric catalysis polymerization kinetic resolution

Privilege Flow Oriented Intrusion Detection Based on Hidden Semi-MarkovModel

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Wuhan university Journal of Natural Sciences 2005年第1期10卷 137-141页

作者： ZHONG An-ming 1, JIA Chun-fu 1,2.1.College of Information technology and Sciences, Nankai university, {2. 300071,china 2.state key laboratory of Information Security, Institute of Software of Chinese Academy of Science, Beijing 100039,china College of Information technology and Sciences Nankai University Tianjin 300071 China

A privilege flow oriented intrusion detection method based on HSMM (Hidden semi-Markov Model) is discussed. The privilege flow model and HSMM are incorporated in the implementation of an anomaly detection IDS (Intrusion Detection System). Using the dataset of DARPA 1998, our experiment results reveal good detection performance and acceptable computation cost.

关键词： key words intrusion detection privilege flow model HSMM

Measurement of the linear electro-optic coefficient of a minute cBN sample

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Science china(Technological Sciences) 2005年第2期48卷 233-340页

作者： DOU Qingping1, , MA Haitao1, JIA Gang1, CHEN Zhanguo1 2.& ZHANG Tiechen3 1. College of Electronic Science and Engineering, state key {2. on Integrated Optoelectronics, Jilin university, Changchun 13002., china 2. Mudanjiang Normal Institute, Mudanjiang 157012. china 3. state key {2. of Superhard Materials, Jilin university, Changchun 130012. china 1. College of Electronic Science and Engineering State Key Laboratory on Integrated Optoelectronics Jilin University 130023 Changchun China 2. Mudanjiang Normal Institute 157012 Mudanjiang China 3. state key {2. of Superhard Materials Jilin University 130012 Changchun China

Cubic boron nitride (cBN) is a kind of artificial (synthetic) crystal. Transverse electro-optic modulation in a minute cBN sample was carried out. Basing on the practical form of the crystal, we established the theoretical and experimental method according to the sample. For the first time, the linear electro-optic effect was observed in cBN, and half-wave voltage of the cBN sample was measured successfully. Furthermore, its linear electro-optic coefficient was calculated at 1.17×10?14 m/V.

关键词： cBN crystal, linear electro-optic effect, half-wave voltage, linear electro-optic coefficient.

Analysis of a kind of quantum cryptographic schemes based on secret sharing

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Science china(Physics,Mechanics & Astronomy) 2009年第9期52卷 1313-1316页

作者： ZHANG XingLan1 & JI DongYao2.1 College of Computer Science and technology, Beijing university of technology, Beijing 10012., china 2.state key laboratory of Information Security, Graduate university of Chinese Academy of Sciences, Beijing 100049, china College of Computer Science and technology Beijing University of Technology Beijing 100124 China state key {2. of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China

Recently, Yang et al. proposed a kind of quantum cryptographic schemes based on secret sharing. The main idea is drawn from the case, where any n participants who share a secret K can co-operate as K does. This process can be applied to encryption, authentication, signature and so on. Unfortunately, since there is no identity authentication of the share's holder, these schemes inherit the limitation of secret sharing in practice. If some participants do not follow the protocol, the protocol would be a failure at last. Moreover, these schemes encounter another serious attack. Any two participants can co-operate to defeat the schemes by sending different shares to the parties unknown to the distributor of the secret K, such that these parties can execute the protocol as well. The attack proves that it is not enough for quantum cryptographic schemes that only the secret key is secure.

关键词： quantum identity authentication quantum secure direct communication quantum signature secret sharing

Damage mechanisms during lapping and mechanical polishing CdZnTe wafers

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Rare Metals 2010年第3期29卷 276-279页

作者： LI Yan,KANG Renke,GAO Hang,and WU Dongjiang key laboratory for {2. and Non-Traditional Machining technology (Ministry of Education),Dalian university of technology,Dalian 11602.,china key laboratory for {2. and Non-Traditional Machining technology (Ministry of Education) Dalian University of Technology Dalian China

CdZnTe wafers were machined by lapping and mechanical polishing processes,and their surface and subsurface damages were *** surface damages are mainly induced by three-body abrasive wear and embedded abrasive wear during lapping process.A new damage type,which is induced by the indentation of embedded abrasives,is found in the *** a floss pad is used to replace the lapping plate during machining,the surface damage is mainly induced by two-body abrasive and three-body abrasive wear,and the effect of embedded abrasives on the surface is greatly ***,this new damage type nearly disappears on the subsurface.

关键词： lapping mechanical polishing wafers surface subsurface abrasive