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POLYMERIZATION OF p-DIETHYNYLBENZENE INITIATED BY Ni(C≡CC_6H_4C≡CH)_2(PPH_3._2

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chinese Journal of Polymer Science 2001年第3期19卷 303-309页

作者： Mu-jie Yang Xiao-wei Zhan Department of Polymer Science and Engineering Zhejiang University Hangzhou 3.0027, china present address: {3. of Chemistry, chinese academy of sciences, beijing 100080, china 浙江大学浙江杭州

Homogeneous polymerization of p-diethynylbenzene initiated by nickel acetylide Ni(C ≡ C C_6H_4 C ≡ CH)_2(PPh_3._2has been investigated in terms of different solvents, addition agents, atmosphere gases, catalyst concentrations, monomerconcentrations and polymerization temperatures. The yield and catalytic efficiency approach 88% and 11. 1 kg polymer/molNi, respectively, under the optimum conditions: [cat] = 0.01 mol/L, [M] = 1.0 mol/L, NEt_3.cat (mol ratio) = 3.5, 1,4-dioxane/toluene (volume ratio) = 1 and T = 25℃ for 5 h. The polymerization rate equation can be expressed as R_p =k_p[M][cat]~2, where k_p= 0.47 L^2. mol^(-2)·S^(-1) (25℃). The overall polymerization activation energy was found to be203.kJ·mol^(-1). Poly(p-diethynylbenzene) so obtained is soluble in THF, CHCl_3.and toluene with weight-average molecularweights as high as 27, 100 and a rich-trans extended π-conjugated polyene chain structure with pendent groups ofp-C_6H_4C≡CH.

关键词： Polymerization p-Diethynylbenzene Nickel acetylide Catalyst

An optimization approach to the similarity criteria of flows and its application

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Progress in Natural Science:Materials International 2006年第3期16卷 241-247页

作者： ZHOU Jifu and LI Jiachun (institute of Mechanics, chinese academy of sciences, beijing 100080,{3.) [a]institute of Mechanics Chinese Academy of Science Beijing China

In the present paper, we propose an optimization approach to investigate the similarity criteria of complex flows. With this approach, we may identify the dominant dimensionless variables governing complex flows by numerical sensitivity analysis. Firstly, we define the sensitivity factor and examine its dependence on the dimensionless variables. Then, we apply this approach to study the similarity criteria of porous media flow in a presumed oil reservoir. The similarity principle obtained from the numerical sensitivity analysis is in agreement with the theoretical law, thus demonstrating the feasibility of the proposed optimization approach. Further explanation is given by analyzing the deviation of pressure distribution in a model from its prototype. In addition, we examine the effects of flow parameter variation on the sensitivity factors and find that the dominant dimensionless variables may change from different sets of parameters.

关键词： similarity optimization sensitivity analysis complex flows model.

Onset of cavitation by the strong tension spike from a tube-arrest apparatus

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Science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 301-305页

作者： YING ChongFu & LI Chao institute of acoustics,chinese {3. of sciences,beijing 100190,china 1. institute of acoustics Chinese Academy of Sciences Beijing 100190 China

Our earlier paper has identified a wave of Type 1 that is the pressure wave generated in the liquid-filled glass tube through the tube-arrest method by pulling and arresting the tube,when cavitation is prohibited. If cavitation is produced,a wave of Type 2 generally appears. The present paper takes the transition between wave types as indication of cavitation onset,and looks for a liquid parameter which controls the onset. One such an attempt shows the concentration of a dissolved gas in the liquid is the controlling factor with the result that the threshold of cavitation onset decreases with the increase of the concentration. Then a specially designed experiment reveals that possibly the mobility of the gas molecules (and also that of the liquid molecules) transiently affects the threshold so as to induce a large rise and fall in time of hours. The threshold finally settles down to some stable value under atmospheric pressure.

关键词： tube-arrest method cavitation onset controlling parameter concentration of dissolved gas mobile gas molecules liq-uid tensile strength

Cyclic Heating-Annealing and Boltzmann Distribution of Free Energies in a Spin-Glass System

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Communications in Theoretical Physics 2007年第7期48卷 179-182页

作者： ZHOU Hai-Jun institute of Theoretical Physics,the chinese academy of sciences,beijing {3.,china institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China

Ergodicity of a spin-glass is broken at low temperatures;the system is trapped in one of many ergodicconfigurational *** between different ergodic domains are achievable through a *** this experiment is repeated infinite times,all ergodic configurational domains will be visited with frequencesthat decreasing exponentially with their free *** mean free energy density of a spin-glass system on a randomgraph is calculated based on this free energy Boltzmann distribution in the present work,by means of the cavity approach.

关键词： spin-glass ergodicity-broken cavity method

SYNTHESIS OF POLY(ETHYLENE TEREPHTHALATE)-POLYCAPROLACTONE BLOCK COPOLYMER BY DIRECT COPOLYMERIZATION

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chinese Journal of Polymer Science 1999年第3期17卷 231-235页

作者： Shen-guo Wang Kai Tang institute of Chemistry, chinese academy of sciences, beijing 100080,{3. chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

Po ly(ethylene terephthalate)-polycaprolactone block copolymer (PCL-b-PET) is a polyester with improved biodegradability. In the present paper, a new direct copolymerization method of epsilon-caprolactone (epsilon-CL) and bishydroxyethylene terephthalate (BHET) in the presence of Ti(OBu)(4) was proposed for the synthesis of PCL-b-PET. The PCL-b-PET copolymer was characterized by IR, GPC and H-1-NMR techniques, and the effects of synthesis conditions, such as temperature, reaction time and concentration of catalyst on the copolymerization were discussed.

关键词： poly(ethylene terephthalate)-polycaprolactone block copolymer direct copolymerization biodegradable polymer

Ordering of the α-Fe(Si) Crystallization Phase in Annealed Fe_(73.5)Cu_1Mo_3.i_(13.5)B_9 Alloy

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Journal of Materials Science & Technology 1997年第1期13卷 37-40页

作者： Jianhua LIU Xiangyi ZHANG and Yangzeng ZHENG (Dept. of Materials Engineering, Yanshan University, Qinhuangdao 066004, china)Jinhua ZHAO and Riping LIU (institute of Physics, chinese academy of sciences ,{3., china)(present address: institute Dept. of Materials Engineering Yanshan University Qinhuangdao 066004 China institute of Physics Chinese Academy of Sciences Beijing 100080 China

The ordering of the α-Fe(Si) crystallization phase in annealed Fe73.5Cu1Mo3.i13.5B9 alloy has been studied using XRD method. The α-Fe(Si) phase in Fe73.5Cu1Mo3.i13.5B9 alloy annealed at 460℃ for 1 h consists of the DO3.type ordered region with spherical shape and disordered region. The size of DO3.ordered region increases with the annealing temperature. When the annealing temperature is 560℃, the size of the ordered region in the α-Fe(Si) grain is 14.0nm,which is nearly as large as that of the α-Fe(Si) grain (14.2 nm) and the degree of order of the α-Fe(Si) phase is about 0.78. When Fe73.5Cu1 Mo3.i13.5B9 amorphous alloy is annealed at 520℃， with the increment of the annealing time, the shape of the DO3.ordered region in the α-Fe(Si) phase is spheroidal at the beginning of the annealing and becomes spherical and has asize of 12.8 nm when the annealing time is 60 min. In addition, the DO3.superlattice lines of the α-Fe(Si) phase will vanish if Fe73.5Cu1Mo3.i13.5 B9 amorphous alloy is annealed for 1 h at 750℃.

关键词： Crystallization Phase in Annealed Fe Cu1Mo3.i Ordering of the B9 Alloy Si Mo

Entropy of three-dimensional BTZ black holes

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中国科学：物理学、力学、天文学英文版 2004年第3期47卷 277-283页

作者： GAO Changjun1,2 & SHEN Yougen1,2,3.4 1.Shanghai Astronomical Observatory,chinese academy of sciences,Shanghai 20003.,{3.(mailing address) 2.National Astronomical Observatories,chinese academy of sciences,beijing 100012,{3. 3.institute of Theoretical Physics,chinese academy of sciences,beijing 100080,{3. 4.Shanghai United Center for Astrophysics,Shanghai 20023.,{3. 1. Shanghai Astronomical Observatory Chinese Academy of Sciences 200030 Shanghai China 2. National Astronomical Observatories Chinese Academy of Sciences 100012 Beijing China 3. institute of Theoretical Physics Chinese Academy of Sciences 100080 Beijing China 4. Shanghai United Center for Astrophysics 200234 Shanghai China

The entropies of scalar field and neutrino field are calculated in the background of three-dimensional BTZ black hole. Considering statistical physics,we propose not to consider the superraradiant modes for bosons (Fermion fields do not display supperradiance).In fact,the nonsuperradiant modes do contribute exactly the area entropy for both bosons and fermions. The result shows that the neutrino field entropy is 3.2 times the scalar one.

关键词： BTZ black holes, entropy, supperradiant modes.

A simple proof of the formal duality of the Kerdock and Preparata codes

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chinese Science Bulletin 2000年第14期45卷 1279-1282页

作者： WAN Zhexianinstitute of Systems Science, chinese academy of sciences, beijing 100080,{3. institute of Systems Science Chinese Academy of Sciences Beijing China

The nonlinearity of the Z2-Kerdock code Km+1, where m is an odd integer ≥3. is not at all obvious. By regarding Km+1 as the binary image of the Z4-Kerdock code .,K(m) under the Gray map[1], a simple proof can be achieved (cf. Theorems 8.7 and 8.9 of [2]). Similarly, the formal duality of the Z2-Kerdock code Km+1 and the Z2-Preparata code Pm+1 is even more not at all obvious. A simple proof is given in the present note, by regarding Km+1 as the binary image of .K (m) and using the duality of .K(m) and the Z4-Preparata code . (m) established in [1].

关键词： 4-code. Kerdock code Preparata code formal duality.

Value of ecosystem services in china

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chinese Science Bulletin 2000年第10期45卷 870-876页

作者： CHEN Zhongxin & ZHANG XinshiLaboratory of Quantitative Vegetation Ecology, institute of Botany, chinese academy of sciences, beijing 100093.{3. Current address: institute of Natural Resources and Regional Planning, chinese academy of Agricultural sciences, beijing 100081,{3. Laboratory of Quantitative Vegetation Ecology Institute of Botany Chinese Academy of Sciences Beijing China

The function and services are the important components of the life-support system in theplanet, as well as the basic elements for sustainable development of environment and society. It is a must to evaluate it for incorporating it with the social-economic system. It is also an important approach to draw the public attention on the environmental and ecosystem conservation. In this study, the ecosystem function and services in china were estimated by employing the classification and economic parameters from Costanza et al. The type and area of terrestrial ecosystems were extracted from Vegetation Map of china (1:4 000 000), and then the distribution map of ecosystem services of china was drawn. According to our calculation, the total value of ecosystem services in china is 77 83..48×108 RMB yuan per annum. The value for terrestrial ecosystem is 56 098.46×108 yuan per annum, and that for marine ecosystem is 21 73..02×108 yuan per annum. The value of ecosystem services in china is 1.73.times bigger

关键词： ecosystem function service.