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Double-excited resonant structure of photoionization

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Science China Mathematics 1997年第7期40卷 738-744页

作者：刘锦超杨向东王宗笠程延松 Institute of Physics Sichuan Union UniversityChengdu 610065China Department of Physics University of VirginiaChariottesvilleVA 22901USA Department of Physios Chongqing UniversityChongqing 630044China

The dominant diagrams were found in double-excited resonant structure of photoionization by using many-body perturbation *** on the characteristics of these diagrams,the couple-equation method was improved,and the summation of specific classes of these diagrams is to an infinite order,and the resonant peaks with the widths are obtained *** doubled-excited resonant structures (2p,3s)→(3p,np),(3p,nf),(3d,nd),(3d,ns) and (4s,ns) of the photoionization processes 2p→ks,kd are *** photoionization with excitation process (2p,3s)→(3p,kp) was included in the *** results of calculations are compared with the experimental data from 38.5 to 46.8 eV photon energies,which are in good agreement with the experiment.

关键词： double-excited resonance photoionization many-body perturbation.

Electro-optic and Photorefractive Properties of Doped Poly (N-Vinylcarbazole)

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Chinese Physics Letters 1997年第6期14卷 474-477页

作者： WANG Shu-feng HUANG Zhi-wen CHEN Zhi-jian GONG Qi-huang ZHANG Zhi-jie CHEN Hui-ying Department of Physics Mesoscopic Physics LaboratoryPeking UniversityBeijing 100871 Department of Chemistry Peking UniversityBeijing 100871

In this work,100μm-thick doped poly(N-vinylcarbazole)films with different contents of the electro-optic(EO)chromophore 2,5-dimethyl-4-(p-nitrophenylazo)anisole and plasticizer N-ethylcarbazole were prepared and sandwiched between two indium-tin oxide-covered glass *** EO measurements and two-beam-coupling experiments were performed by using a single mode(TEM00)He-Ne *** the EO coefficient and the gain for two-beam-coupling were found to be strongly depending on the content of plasticizer.

关键词： Photorefractive coupling beam

Highly Oriented Diamond Film Growth by Atomic Force Microscopy

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Chinese Physics Letters 1998年第11期15卷 822-824页

作者： LI Jian-long MENG Ge WU Ke-hui WANG En-ge state Key Laboratory for Surface Physics Institute of PhysicsChinese Academy of SciencesBeijing 100080

Diamond thin films are grown with microwave plasma chemical vapor deposition method on silicon(100)substrates from methane/hydrogen gas mixture,and characterized with atomic force microscopy The results show that most of the diamond crystallites are highly oriented with the(100)planes parallel to the silicon *** structures are found in the film,indicating a combination of layer-by-layer and island *** spectrum and x-ray diffraction also confirm the present results.

关键词： Diamond layer island

EFFECT OF SEQUENCE STRUCTURE ON THE THERMOTROPIC LIQUID CRYSTALLINE PROPERTIES OF POLYESTERAMIDES BASED ON DIMETHYLBENZIDINE, BISPHENOL-A AND ρ-TEREPHTHALYL CHLORIDE

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Chinese Journal of Polymer Science 1998年第1期16卷 81-85页

作者：戴彪高彦芳王晓工周其庠刘德山 Institute of Polymer Science and Engineering Department of Chemical Engineering Tsinghua University Beijing 100084 China

A series of thermotropic liquid crystalline polyesteramides with differ-ent sequence structure based on dimethylbenzidine (DMBD), bisphenol-A(BPA) and p-terephthalyl chloride (TPC) was synthesized by changing the feeding order of monomers inlow temperature solution polycondensation system. By means of NMR and a computer pro-gram the sequence structure parameters were measured. The effect of sequence structureon liquid crystalline phase transition temperature of PEAs obtained was investigated.

关键词： Liquid crystal Polyesteramide Sequence structure Melting temperature

CHARACTERIZATION OF AMPHIPHILIC AND MICROPHASE SEPARATED GRAFT COPOLYMERS Ⅱ SURFACE CHARACTERIZATION AND IN VITRO BLOOD-COMPATIBILITY ASSESSMENT OF POLYSTYRENE-GRAFT-ω-STEARYLPOLY (ETHYLENE OXIDE)

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Chinese Journal of Polymer Science 1995年第2期13卷 112-125页

作者：邱永兴俞小洁封麟先杨士林 Department of Polymer Science and Engineering Zhejiang UniversityHangzhou 310027

This paper reported the research results concerning the surface characterization ofpolystyrene-graft-w-stearyl poly(ethylene oxide) (PS-g-SPEO) by means of XPS,contactangle measurement and TEM, and its in vitro blood compatibility assessment by measuringthe plasma recalcification time (RT) and partial thromboplastin time (PTT). The XPSresults demonstrated that the surface and bulk composition of the PS-g-SPEO graftcopolymers differ remarkably from each other,and that SPEO component was constantlyenriched at the copolymer/air interface. Contact angle studies indicated that the surfacewater wettability can be adjusted effectively by changing the composition of the ***-g-SPEO graft copolymers can undergo microphase separation as clearly illustrated byTEM photographs. The relationship between the surface properties of PS-g-SPEO graftcopolymer and its blood compatibility was also discussed.

关键词： Polystyrene-g-w-stearyl-poly (ethylene oxide) Surface properties Graft copolymer Blood compatible material

Two Mechanisms in a Relativistic Electron Cyclotron Maser with a Special Quasioptical Cavity

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Chinese Physics Letters 1995年第10期12卷 597-600页

作者： LIU Pukun YANG Zhonghai LIU Shenggang QIAN Shangjie Institute of High Energy Electronics University of Electronic Science and Technology of ChinaChengdu 610054 Southwestern Institute of Physics Chengdu 610041

In a relativistic electron cyclotron maser with an axisymmetrical quasioptical cavity of oblique rotation at arbitrary angle,the rotating angle has a great influence on beam-wave *** different physical mechanisms are found with the rotating angle ranging from 0°to 90°.One is cyclotron auto-resonance maser regime for small angle,with small optimized external magnetic field;the other is electron cyclotron resonance maser regime for large angle,with comparatively large optimized magnetic field.

关键词： angle rotating Electron

Variation of Surface Adhesion Force During the Formation of OTS Self-assembled Monolayer Investigated by AFM

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Chinese Journal of Chemical Engineering 1999年第4期7卷 345-350页

作者：徐国华 HigashitaniKo DepartmentofChemicalEnginesring ZhejiangUniversityHangzhou310027China DepartmantofChemicalEnineering KyotoUniversityKyoto606-01Japan

Variation of the surface adhesion force during the formation of octadecyl trichlorosilane (OTS) self-assembled monolayer on a glass substrate surface was investigated by atomic force microscope (AFM). The research shows that the hydrophobicity and the adhesion force of the sample surface increases gradually while the substrate surface is covered by OTS molecules as the reaction proceeds. After 15min reaction, a close-packed and smooth OTS self-assembled monolayer could form on the glass substrate surface with an advancing contact angle of 105° and an interfacial energy of 55.79mJ·m-2.

关键词： surface adhesion force atomic force microscope octadecyl trichlorosilane selfassembled monolayer

THE ASYMMETRIC SYNTHESIS OF AMINO ACIDS UNDER POLYMER-SUPPORTED PHASE TRANSFER CATALYTIC CONDITION

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Chinese Journal of Polymer Science 1998年第4期16卷 356-361页

作者：王咏梅张政朴王真孟继本霍奇 Department of Chemistry Nankai University Tianjin 300071 China The state Key Laboratory of Functional Polymer Materials for Adsorption and Separation Institute of Polymer Chemistry Nankai University Tianjin 300071 China Department of Chemistry University of Manchester Manchester M13 9PL U.K.

The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical alpha-amino acids. This is a new method for the asymmetric synthesis of alpha-amino acids. The influences of catalyst, temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.

关键词： asymmetric organic synthesis polymer supported phase transfer catalysts (PS-PTC) alpha-amino acids

SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE) SIDE CHAIN STRUCTURES

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Chinese Journal of Polymer Science 1993年第1期11卷 67-75页

作者：邱永兴俞小洁封麟先杨士林 Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027

Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.

关键词： PEO AIBN SIDE CHAIN STRUCTURES SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY ETHYLENE OXIDE PS