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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 Polymer Science and Engineering Peking University Beijing 100871, China National Research institute for Family Planning Beijing 100081, China Peking Univ Dept Polymer Sci & Engn Beijing 100871 Peoples R China natl Res inst Family Planning Beijing 100081 Peoples R China

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)=0.37, respectively.

关键词： 3-benzyloxymethyl 1,4-dioxane-2,5-dione DL-lactide reactivity ratios

Scanning　Analysis　of　REE　in　Bastnaesite　with　Synchrotron　Radiation　X－Ray　Fluorescence　Microprobe

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Journal of Rare Earths 1996年第4期14卷 308-311页

作者：安庆骧王锐兵邓赛文潘巨祥吴应荣吴澄宇 natl RES CTR GEOANAL BEIJING 100037PEOPLES R CHINA inst HIGH ENERGY PHYS BEIJING 100039PEOPLES R CHINA CHINESE ACAD GEOL SCI INST MINERAL DEPOSITSBEIJING 100037PEOPLES R CHINA

The content of REE(***) in bastnaesite was measured by synchrotron radiation X-ray fluorescence *** analysis makes use of excitation of the REE K lines between 33 and 50 *** white beam from a Wiggler source at the Beijing Electron Positron Collider(BEPC) of the National Laboratory,in order to excite the *** bastnaesite from the same mineral area was powdered to particle size≤300 *** was then divided into two *** portion was used to be determined by XRF after depositing with oxalate and transforming into *** other was pressed into disk without any binder as the reference *** weight and the diamieter of the disk were 15 g and 26 mm respectively.

关键词： Synchrotron radiation X-ray fluomcence Rare earth analysis Bastnaesite

Superperiodic Feature on Silicon-Sputtered Highly Oriented Pyrolytic Graphite

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Journal of Materials Science & Technology 2003年第3期19卷 246-248页

作者： Gulping DAI, Tiansheng XIE, Huiming CHENG Hengqiang YEShenyang National Laboratory for Materials Science, institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Chinese Acad Sci Inst Met Res Shenyang Natl Lab Mat Sci Shenyang 110016 Peoples R China

Superperiodic feature was observed by scanning tunneling microscopy (STM) on the surface of highly oriented pyrolytic graphite (HOPG) on which silicon was sputtered. The superlattice was analyzed by the moire pattern hypothesis, and the lattice constant is 7.03 nm. For the superlattice, the observed boundaries between the superlattice and the normal graphite areas were zigzag, which was in good agreement with the result predicted theoretically. In addition, the observed lattice constants varied slightly in the superperiodic feature area. This implies the role of intralayer strain in the formation of the observed superlattice on the graphite surface.

关键词： Highly oriented graphite Scanning tunneling microscopy Superlattice Silicon

Study of the primordial lithium abundance

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Science China(Physics,Mechanics & Astronomy) 2011年第S1期54卷 67-72页

作者： LI ZhiHong1, LI ErTao1, SU Jun1, LI YunJu1, BAI XiXiang1, GUO Bing1, WANG YouBao1, CHEN YongShou1, HOU SuQing1, ZENG Sheng1, LIAN Gang1, SHI JianRong2 & LIU WeiPing1 1 China institute of Atomic Energy, Beijing 102413, China 2National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China China inst Atom Energy Beijing 102413 Peoples R China Chinese Acad Sci Natl Astron Observ Beijing 100012 Peoples R China

Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at China institute of Atomic Energy, Beijing. The Standard BBN (SBBN) network calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the SBBN abundances of 6Li and 7Li.

关键词： big bang nucleosynthesis element abundance nuclear reaction network

Thermodynamic Assessment of Interaction Relation between Lanthanum and Constituent Elements in Sn-Pb Alloy

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Journal of Rare Earths 2001年第2期19卷 107-109页

作者：薛松柏马鑫钱乙余 Harbin inst Technol Natl Key Lab Welding Harbin 150001 Peoples R China Minist Informat Ind Natl Key Lab Reliabil Phys Elect Prod Guangzhou 510610 Peoples R China Hiroshima Univ Dept Mech Engn Hiroshima 739 Japan

The interaction relation between lanthanum and the constituent elements of Sn-Pb alloy system was analyzed by using the thermodynamic models including Miedema formation energy model for binary system, Tanaka modification by excess entropy and the Chou geometric model for ternary system. The thermodynamic calculaton results show that lanthanum has higher affinity for Sn in the Sn-Pb system. This is an important foundation for the improvement of the metallurgical properties of Sn-Pb solder alloy by adding rare earth elements.

关键词： rare earths lanthanum Sn-Pb alloy interaction thermodynamic

Thermodynamic Analysis,Simulation and Optimization on Energy Savings of Ideal Internal Thermally Coupled Distillation Columns

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Chinese Journal of Chemical Engineering 2000年第1期8卷 57-63页

作者：刘兴高马龙华钱积新 Zhejiang Univ Inst Ind Proc Control Hangzhou 310027 Peoples R China Zhejiang Univ Natl Lab Ind Control Technol Hangzhou 310027 Peoples R China

Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.

关键词： distillation thermal coupling energy savings simulation optimization

Growth and Microstructure of r.f. Sputtered Fe/Ti Multilayers

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Journal of Materials Science & Technology 2001年第5期17卷 521-524页

作者： Wei WANG Shenyang National Laboratory for Materials Science, institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Lishi WEN Department of Surface Engineering of Materials, institute of Metal Research, Chinese Academy of Science Chinese Acad Sci Inst Mat Res Shenyang Natl Lab Mat Sci Shenyang 110016 Peoples R China Chinese Acad Sci Inst Mat Res Dept Surface Engn Mat Shenyang 110016 Peoples R China

Fe/Ti multilayers with different modulation wavelengths (Lambda) prepared by r.f. sputtering has been investigated by using cross sectional transmission electron microscopy (XTEM). It was observed that the columnar structure, interface morphology, and metastable phase presented at the interface of the multilayer system strongly depend on the bilayer thickness (Lambda). For high period multilayers, the waviness wavelength of interfaces is about two times broader than the column diameter. For a sample with Lambda =30 nm, its column width and waviness wavelength was about 80, and 190 nm, respectively. Both of them decreased with the reduction of Lambda, so as to nearly equal values of column diameter and waviness wavelength were obtained. The Fe and Ti grains of both 30 nm and 6 nm multilayers are polycrystalline, and have a textured structure. In short bilayer thickness (Lambda =6 nm), the intermetallic compound Fe2Ti was presented at the interfaces due to solid state reaction; for Lambda =2 nm, amorphous phase Ti-rich layer was formed at the interfaces, resulting in a sharp interface multilayer structure.

关键词： Ti Growth and Microstructure of r.f Sputtered Fe/Ti Multilayers Fe

A Simulator for Producing of High Flux Atomic Oxygen Beam by Using ECR Plasma Source

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Journal of Materials Science & Technology 2004年第6期20卷 759-762页

作者： Shuwang DUO, Meishuan LI and Yaming ZHANGShenyang National Laboratory for Materials Science, institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Shenyang natl. Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

In order to study the atomic oxygen corrosion of spacecraft materials in low earth orbit environment, an atomic oxygen simulator was established. In the simulator, a 2.45 GHz microwave source with maximum power of 600 W was launched into the circular cavity to generate ECR (electron cyclotron resonance) plasma. The oxygen ion beam moved onto a negatively biased Mo plate under the condition of symmetry magnetic mirror field confine, then was neutralized and reflected to form oxygen atom beam. The properties of plasma density, electron temperature, plasma space potential and ion incident energy were characterized. The atomic oxygen beam flux was calibrated by measuring the mass loss rate of Kapton during the atomic oxygen exposure. The test results show that the atomic oxygen beam with flux of 1016-1017 atoms-cm-2·s-1 and energy of 5-30 eV and a cross section of φ80 mm could be obtained under the operating pressure of 10-1-10-3 Pa. Such a high flux source can provide accelerated simulation tests of materials and coatings for space applications.

关键词： Atomic oxygen Low earth orbit space environment ECR plasma Microwave

A Pivotal Role of Cell Wall in Cadmium Accumulation in the Crassulaceae hyperaccumulator Sedum plumbizincicola

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Molecular Plant 2017年第5期10卷 771-774页

作者： Peng, Jia-Shi Wang, Yue-Jun Ding, Ge Ma, Hai-Ling Zhang, Yi-Jing Gong, Ji-Ming Chinese Acad Sci Natl Key Lab Plant Mol Genet Shanghai Inst Biol SciNatl Ctr Plant Gene Res Sh CAS Ctr Excellence Mol Plant SciInst Plant Physi Shanghai 200032 Peoples R China Jiangxi Acad Agr Sci Crops Res Inst Nanchang 330200 Jiangxi Peoples R China

Dear Editor,Heavy metal pollution has become a public concern （Mohammed et al., 2011）, and the development of efficient phytoremediation （i.e. using plants to clean polluted environment） requires better understand... 详细信息

关键词： Pivotal Role Cell Wall Cadmium Accumulation