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MORPHOLOGICAL TRANSITION BETWEEN VESICLES AND TUBULES FOR A GLYCOpolymer-CONTAINING AMPHIPHILIC DIBLOCK COpolymer IN AQUEOUS SOLUTIONS

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Chinese Journal of polymer science 2001年第3期19卷 297-301页

作者： Zi-chen Li Yue Shen Yu-zeng Liang Fu-mian Li department of polymer {2. & Engineering College of {3. peking university beijing 100871, china 北京大学北京

The morphological transition of molecular assemblies in aqueous solutions for a new amphiphilic diblock copolymer induced by changing the initial solvent conditions was studied by transmission electron microscopy (TEM). The copolymer was polystyrene(77)-b-poly[2.(beta -D-glucopyranosyloxy)ethyl acrylate (6)] (PSt(77)-b-PGEA(6)) and the solvent was a mixture of DMF and THF. PSt(77)-b-PGEA(6) yields vesicles and tubules when it is initially dissolved in THF and DMF respectively. The morphological transition between vesicles and tubules can be achieved by simply varying the amounts of THF and DMF, or changing the temperature at which the aggregates were prepared.

关键词： block copolymer amphiphile glycopolymer self-assembly tubule vesicle

IMPACT PROPERTIES OF METALLOCENE - CATALYZED ETHYLENE-α-OLEFIN COpolymerS

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Chinese Journal of polymer science 2002年第5期20卷 473-480页

作者： Xu-rong Xu Jun-ting Xu Lin-xian feng department of {2. {3. and Engineering Zhejiang university Hangzhou 3.002.,china department of {2. {3. and Engineering College of chemistry & Molecular Engineering peking university beijing 100871, china department of polymer {2. and Engineering Zhejiang University Hangzhou 310027

The impact properties of two selected metallocene-catalyzed ethylene-butene copolymers and one conventionalcopolymer were evaluated using Izod impact test. It is found that the metallocene-catalyzed copolymer shows superior impactproperties. This result was explained on the basis of the more homogeneous inter-molecular composition distribution andnarrower molecular weight distribution, which leads to more homogeneous morphology with fewer defects. Stepwisecrystallization improves the impact properties, especially in the crack propagation process, to a large extent. This is due to thedecrease of entanglements by stepwise crystallization, which is advantageous for the chain slip and shear. The polymer withheterogeneous intra-molecular composition distribution exhibits a more evident improvement of impact properties understepwise crystallization.

关键词： Metallocene-catalyzed ethylene-butene copolymer Impact properties Molecular heterogeneities Thermal treatment

Ordered Bicontinuous Network Structures Regulated by Orientational Interactions in a Rod-Coil Block Copolymer

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Chinese Journal of polymer science 2024年第5期42卷 636-642,I0008页

作者： Xiao-Lin Lyu Shi-Chu Yang An-qi Xiao Ping-Ping Hou Wei Zhang Hong-Bing Pan Zhi-Hao Shen Xing-He Fan qi-{2. {3. beijing National Laboratory for Molecular sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Key Laboratory of Advanced Materials Technologies International(HongKong Macao and Taiwan)Joint Laboratory on Advanced Materials TechnologiesCollege of Materials Science and EngineeringFuzhou UniversityFuzhou350108China

The rich phase behavior of block copolymers(BCPs)has drawn great attention in recent ***,the double diamond(DD)phase is rarely obtained because of the competition between the minimization of interfacial energy and packing ***,a rod-coil BCP containing mesogen-jacketed liquid crystalline polymer is designed to acquire ordered bicontinuous network *** reduction of internal energy originating from the orientational interaction among the rod blocks can compensate for the free energy penalty of packing frustration to stabilize the DD *** resulting BCP can also experience lamellae-to-DD and double gyroid-to-lamellae transitions by changing the annealing *** results make the rod-coil BCP an excellent candidate for the self-assembly of ordered network structures,demonstrating great potential in nanopatterning and metamaterials.

关键词： Block copolymer Rod-coil Ordered bicontinuous phase Double diamond Double gyroid

Electronic structure and magnetism of R(Fe,Si)_(12. (R=Y,Nd)

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science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 195-202页

作者： SUN Guang’ai1, CHEN Bo1, DU Honglin2. FAN Zhijian1, GAO Tao3.& qi Xinhua3.. Institute of Nuclear Physics and chemistry,{2. Academy of Engineering Physics, Mianyang 62.900,{2. 2. department of physics, peking university, beijing 100871,{2. 3. Institute of Atomic and Molecular Physics, Sichuan university, Chengdu 610065,{2. Institute of Nuclear Physics and chemistry China Academy of Engineering Physics Mianyang China department of physics Peking university Beijing China Institute of Atomic and Molecular Physics Sichuan University Chengdu China

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)12.compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic mo-ments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total mag-netic moments of RFe10Si2.(R = Y, Nd) are larger than those of RFe10M2.(M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the mag-netic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduc-tion of Si atoms according to spin fluctuation of DOS at Fermi level.

关键词： (L)APW+lo method R(Fe Si)12.R = Y Nd) magnetic moment Density of state.

Status of study on biological and toxicological effects of nanoscale materials

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science china {2. 2005年第5期48卷 385-394页

作者： WANG Bing1, feng Weiyue1, ZHAO Yuliang1, XING Gengmei1, CHAI Zhifang1, WANG Haifang2.& JIA Guang3.1. Laboratory for Bio-Environmental Health sciences of Nanoscale Materials (Nanosafety Lab), Institute of High Energy Physics, Chi-nese Academy of sciences, beijing 100049, china 2. College of chemistry and Molecular Engineering, peking university, beijing 100871, china 3. department of Occupational and Environmental Health sciences, School of Public Health, peking university, beijing 100083. china Laboratory for Bio-Environmental Health sciences of Nanoscale Materials (Nanosafety Lab) Institute of High Energy Physics Chinese Academy of Sciences Beijing China College of chemistry and Molecular Engineering Peking University Beijing China department of Occupational and Environmental Health sciences School of Public Health Peking University Beijing China

Because the physical and chemical properties of nanosized materials mostly differ from the existing microsized materials, their potential impacts on human health and the envi-ronment will be topics under the serious discussions in press and in a number of international scientific journals. We analyze and summarize the existing data of the experimental study on the biological activities and adverse effects of nanoscale materials/particles including single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron powders. Though some biological behaviors of nanoscale materials observed cannot be understood on the basis of the current knowledge, as the existing data are mostly preliminary, it is too early to make some ex-clusive conclusions on biological activities (or the toxicity) of any of nanoscale materials. The experimental techniques, the current topics, and the future research directions for this new re-search field are also discussed.

关键词： nanomaterials, single wall carbon nanotubes, multi wall carbon nanotubes, titanium oxide and iron, biological activity and toxicological effect.

SYNTHESIS OF DIACETYLENE-CONTAINING COPOLYESTERS AND THEIR DFFECT ON ELECTRO-OPTICAL PROPERTIES OF LIQUID CRYSTALS

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Chinese Journal of polymer science 1999年第2期17卷 193-196页

作者： Xiao-fang Chen Yao-wen Bai Yu-guo Ma Chen-hui Wang Dong Zhang Xin-hua Wan qi-feng {2. {3. of polymer science and Engineering, College of chemistry, peking university, beijing 100871, china 北京大学化学院北京 100871 北京大学化学院北京

Some diacetylene-containing copolyesters with different ratios of dipropargyl 1,10-decanate anddipropargyl terephthalate were synthesized. Properties of these copolymers were characterized by differentialscanning calorimetry and polarizing optical microscopy. The copolymer could be cross-linked easily by UVirradiation in a liquid crystal matrix without adding any photoinitiator. The preliminary studies showed thatthe diacetylene-containing polymer network can assist liquid crystal molecules to align with the externalelectric field, thus reducing the response time of display devices.

关键词： Diacetylene-containing copolyesters polymer-stabilized liquid crystals Electo-optical of liquid crystals

COpolymerIZATION AND DETERMINATION OF MONOMER REACTIVITY RATIOS OF DL-LACTIDE WITH 3.BENZYLOXYMETHYL-1,4-DIOXANE-2.5-DIONE

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Chinese Journal of polymer science 2002年第5期20卷 413-417页

作者： Ji-yuan Yang Jian Yu Mei Li Zhong-wei Gu Xin-de feng department of {2. {3. and Engineering peking university beijing 100871, china National Research Institute for Family Planning beijing 100081, china department of polymer {2. and Engineering Peking University 北京 100871 National Research Institute for Family Planning 北京 100081

The copolymerization of DL-LA and 3.BMG was carried out in bulk with stannous 2.ethythexanoate as the catalyst. A series of copolymers with pendant protected groups were obtained and characterized by H-1-NMR and GPC analysis. The monomer reactivity ratios were evaluated by the Fineman-Ross method and the Kelen-Tudos method and found to be r(BMG)=1.96 and r(LA)=0.3., respectively.

关键词： 3.benzyloxymethyl 1,4-dioxane-2.5-dione DL-lactide reactivity ratios

Changes of decay rates of radioactive ^(111)In and ^(3.0}P induced by mechanic motion

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science china {2. 2007年第2期50卷 170-174页

作者： HE YuJian1,qi Fei2.& qi ShengChu3.1 College of {2. and Chemical Engineering,Graduate university of Chinese Academy of sciences,beijing 100049,china 2.No. 1,Gravenhurst Court,Gaithersburg,Md 2.878,USA 3.department of Applied {2.,peking university,beijing {12.,china College of chemistry and Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing China No. 1 Gravenhurst Court Gaithersburg USA department of Applied chemistry Peking University Beijing China

The changes of decay rates of radionuclide 111In(electron capture) and 3.0}(β decay) induced by exter-nal mechanic motion are studied. The results indicate that,in the external circular rotation in clockwise and anticlockwise centrifuge on Northern Hemisphere(radius 8 cm,2.00 r/min) ,the half life of 111In compared with the referred(2.83.d) is decreased at 2.83. and increased at 1.77%,respectively;the half life of 3.0} compared with the referred(14.2. d) is decreased at 3.78% and increased at 1.75%,respec-tively. When the clockwise and anticlockwise rotations increase to 4000 r/min,the half life of 111In is decreased at 11.3.% and increased at 6.3.%,respectively;the half life of 3.0} is decreased at 10.08% and increased at 4.3.%,respectively. When the circular rotation is removed,the decay rates of 111In and 3.0} return back to the referred,respectively. It is found that the external circular rotations in clockwise and anticlockwise centrifuge selectively increased and decreased the decay rates of 111In and 3.0},respec-tively,and the effects are strongly dependent on the strength of circular rotation. It is suggested that these effects may be caused by the chiral interaction.

关键词： circular rotation helical motion 111In 3.0} decay rate chirality

Phase relationship of complex multi-component system in chromate cleaner production

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Progress in Natural science:Materials International 2007年第7期17卷 845-850页

作者： Ge Xinlei~1 Wang Xidong~(1,3.*) Zheng Shili~2.Zhang Mei~1 Zhang Yi~2.(1.department of Physical {3.,{2. of science and Technology beijing,beijing 100083.china 2.Institute of Process Engineering,Chinese Academy of sciences,beijing 100080,china 3.College of Engineering,{13. {2.,beijing 100871,china) department of Physical chemistry University of Science and Technology Beijing Beijing 100083 China College of Engineering Peking University Beijing 100871 China Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

The phase relationships of the complex multi-component systems in the liquid-phase oxidization and separation process related with the chromate cleaner production are investigated theoretically and *** phase diagram of main system Fe- Cr2.4-KOH-O2.f oxidization process and the relationship of its standard Gibbs free energy change with temperature are calculated.A se- ries of phase diagrams of the separation process at different temperatures,such as K（Na）OH-K（Na）2.rO4-H2.,KOH-KAlO2.H2., K（Na）OH-K（Na）2.O3.H2.,K（Na）OH-K（Na）HCO3.H2. and K（Na）HCO3.K（Na）2.rO4-H2. have also been *** ex- periments are carried out to verify the calculated *** results showed that the sub-molten salt media are suitable for the oxidization and separation processes;FeCr2.4can be oxidized across a wide range of temperature;K（Na）2.rO4can be separated from K（Na）AlO2.ystem at appropriate temperature and proper concentration;the crystallization of carbonate is easier than that of K（Na）2.rO4.

关键词： chromite chromate system thermodynamics calculation phase diagram