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PERFORMANCE AND INITIATION MECHANISM OF ISOPROPYLTHIOXANTHONE IN SURFACE PHOTOGRAFTING

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Chinese Journal of Polymer science 2000年第5期18卷 431-435页

作者： Wan-tai Yang Mei-zhen Yin Yu-feng Sun college of material science and engineering, beijing university of chemical technology, beijing 100029, china 北京化工大学北京

In a polymerization model with low density polyethylene (LDPE) as the substrate and acrylic acid (AA) as the monomer, the performance of isopropylthioxanthone (ITX) in initiating surface photografting polymerization was evaluated. The results show that the reactivity of photopolymerization and photografting of ITX locate between benzophenone (BP) and benzildimethylketal (BDK) for polymerization, BDK > ITX > BP; for surface grafting polymerization, BP > ITX > BDK. These results can be explained by a reaction mechanism of the inter-molecular or intra-molecular hydrogen abstraction reaction of ITX.

关键词： photografting polymerization photopolymerization hydrogen abstraction reaction

Effect of surfactants on the structure and photoelectric properties of ITO films by sol-gel method

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Rare Metals 2010年第2期29卷 143-148页

作者： LIU Jiaxiang, WU Da, ZHANG Nan, and WANG Yue college of materials science and engineering, beijing university of chemical technology, beijing 100029, china college of materials science and engineering Beijing University of Chemical Technology Beijing China

The Indium tin oxide（ITO） thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent *** obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol（PEG） were added to the ITO precursor *** influences of surfactants on the structural and photoelectric properties of ITO film samples were *** patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the（400） *** high transmittance（over 95%） was attributed to the preferred orientation and the grain size expansion of ITO *** showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants *** to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.

关键词： surfactants indium tin oxide films sol-gel structure photoelectricity

Interface-directed sol-gel:direct fabrication of the covalently attached ultraflat inorganic oxide pattern on functionalized plastics

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science china Chemistry 2010年第1期53卷 173-182,287-288页

作者： GAN ShengHua,YANG Peng & YANG WanTai State Key Laboratory of chemical Resource engineering college of materials science and engineering,beijing university of chemical technology,beijing 100029,china State Key Laboratory of chemical Resource engineering college of materials science and engineering Beijing University of Chemical Technology Beijing China

For plastic electronics and optics,the fabrication of smooth,transparent and stable crack-free inorganic oxide films(and patterning) on flexible polymeric substrates with strong bonding strength and controllable thickness from nanometers to micrometers is a key but still remains a *** versatile inorganic oxides,silica oxide film as SiOx is especially important because this semiconductor material could provide crucial properties in devices or serve as a base layer for further multilayer *** this paper,we describe a new interface-directed sol-gel method to fabricate flexible high quality silicon oxide film onto commodity *** resulting crack-free silica film has strong covalent bonding with polymer substrates,homogeneous morphology with ultralow roughness,highly optical transparency,tunable thickness from nm to μm,and easy patterning *** fabrication strategy relies on a novel photocatalytic oxidation reaction by photosensitive ammonium persulfate(APS),which is able to fabricate highly reactive hydroxyl monolayer surface on inert polymeric *** kind of hydroxylated surface could serve as nucleation and growth sites to initiate surface sol-gel *** a result,well-defined SiOx film deposition(gelation) occurs,and patterned hydroxylation regions could be easily utilized to induce the formation of patterned oxide film *** strategy also excludes the requirements of clean room and vacuum devices so as to fulfill low-cost and fast fabrication *** application examples from such high quality SiOx layer onto plastics are given but should not be limited within *** is that oxygen permeation rate of SiOx deposited polymer film decreases 25 times than pristine polymer substrate,which is good for the potential packaging *** other one is that silanization monolayer,for example,3-aminopropyltriethoxysilane(APTES),could be successfully constructed onto silica layer through classical silanization reac

关键词： surface patterning silicon oxide sol-gel polymer surface modification functional coatings

Electrochemical Studies of Lithium Intercalation into Graphite Film Electrode for Li^+-ion Batteries

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International Journal of Minerals,Metallurgy and materials 2000年第1期14卷 48-50页

作者： Chuangang Lin Weihua Qiu Qingguo Liu material science and engineering School, university of science and technology beijing, beijing 100083, china material science and engineering School University of Science and Technology Beijing Beijing 100083 China

To study the electrochemical kinetic properties of the Li/Graphite system, cycle voltammerty (CV), ac-impedance and chro- noamperometry (CA) techniques have been used. The results showed that the diffusion of lithium ions in Li_xC_6 is the rate-determining step. The chemical diffusion coefficients of lithium (D_Li) have been estimated for different x values. As for the same material, the value of D_Li was calculated in order to compare the differences among the three techniques.

关键词： electrochemical studies graphite Li^+-ion batteries

Preparation and High Temperature Oxidation Properties of Micro-crystalline MGH754 ODS Alloy Coatings

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Journal of university of science and technology beijing 2001年第1期8卷 28-34页

作者： Huibub Qi Hongmei Pang Yedong He Deren Wang Wei Gao material Seience and engineering School, university of science and technology beijing, beijing 100083, china Department of chemical and material Engineeing, the university of Auckland, New Zealand material science/engineering School Univ. of Science/Technology Beijing Beijing 100083 China

A special coating technique, electro-spark deposition (ESD), was developed to produce micro-crystalline ODS MGH754 alloy coatings on a commercial 1Cr18Ni9Ti stainless steel and a cast Ni20Cr alloy substrates. The coatings have a very fine grain structure and metallurgical bonding with the substrates. The isothermal oxidation tests at 1000 degreesC in air showed that the micro-crystalline ODS alloy coatings had a much reduced oxidation rate and improved scale spallation resistance compared with the uncoated alloys. The selective oxidation of Cr was greatly promoted to form protective and continuous Cr2O3 scales on the alloy surface. Micro-crystallization and oxide dispersions have synergistic effects on the improvement of oxidation resistance. The beneficial effects were discussed based on the experimental results.

关键词： electro-spark deposition (ESD) ODS coating oxidation

Rheological Behaviour for Polymer Melts and Concentrated SolutionsPart Ⅱ: material Function with Nagai Chain Constraints and Determination of Their Parameters from Flow Curves

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Journal of materials science & technology 1995年第2期11卷 141-152页

作者： Mingshi SONG Sizhu WU and Xiuyun DU(Research Institute of Polymeric materials, beijing university of chemical technology, beijing, 100029, china) beijing Univ of chemical technology Beijing China

An integral constitutive equation and a set of material functions for describing the strain history of polymer melts were formulated in terms of the Cauchy-Green and Finger tensors. A simple memory function and the dependence of ηo and τt on M3.4 were derived from the theory of non-linear viscoelasticity with constraints of entanglements for polymer melts and substituted into the Oldroye-Walters-Fredickson constitutive equation. An integral constitutive equation for polymer melts was consequently obtained. Some material functions of the constitutive equation related to certain 'test flow' are examined as follows : (1) simple steady shear flow; (2) steady elongation flow; (3) small-amplitude oscillatory shear flow; (4) stress growth upon the inception of steady shear elongation flow; (5) stress relaxation (modulus and compllance). These theoretical relations for simple steady shear flow were compared with experimental data from our laboratory and references for various polymer melts and concentrated solutions. A good agreement between the theory and experiment was achieved.

关键词： LDPE material Function with Nagai Chain Constraints and Determination of Their Parameters from Flow Curves Rheological Behaviour for Polymer Melts and Concentrated SolutionsPart Flow GR

Photocatalytic degradation kinetics of Rhodamine B cata- lyzed by nanosized TiO_2 film

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Chinese science Bulletin 2003年第1期48卷 49-52页

作者： WEI Gang, ZHANG Yuanjing & XIONG Rongchun college of material science and engineering, beijing university of chemical technology, beijing 100029, china Correspondence should be addressed to Xiong Rongchun (e-mail: xiongrongchun@***) college of material science and engineering Beijing University of Chemical Technology Beijing 100029 China

A fixed bed photocatalytic reactor was de-signed, and dynamic fast scan of UV-Vis adsorption spec-trum was adopted to study the photocatalytic degradation dynamic behavior of Rhodamine B, a kind of dye generally recognized as to be degraded difficultly, on the surface of nanosized TiO2 thin film. The results indicate that the photocatalytic degradation process of Rhodamine B does not comply with the first-order reaction kinetic process. As a result, a kinetic model of Rhodamine B photocatalytic deg-radation reaction is brought forward, and the model is proved by the theoretical deduction and experiment.

关键词：若丹明B 光催化降解动力学含染料废水固定床光催化反应器纳米级二氧化钛薄膜 TiO2

Sensing characterization of Sn/In/Ti nanocomplex oxides for CO, CH_4 and NO_2

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science china(Technological sciences) 2007年第1期50卷 18-26页

作者： BAI ShouLi1, TONG ZhangFa2, LI DianQing1, HUANG XiaoWei3, LUO RuiXian1 & CHEN AiFan1 1 State Key Laboratory of chemical Resource engineering, beijing university of chemical technology, beijing 100029, china 2 School of Chemistry and chemical engineering, Guangxi university, Nanning 530004, china 3 college of Biochemical engineering, beijing Union university, beijing 100023, china State Key Laboratory of chemical Resource engineering Beijing University of Chemical Technology Beijing China School of Chemistry and chemical engineering Guangxi University Nanning China college of Biochemical engineering Beijing Union University Beijing China

The nanocomplex oxides of Sn-In and Sn-In-Ti were prepared by controlled co-precipitation method as sensing materials of semiconductor gas sensors for detection of CO, CH4 and NO2. Through manipulating the Sn/In cation ratio, metal salt total concentration, precipitation pH value and aging time, the nanocrystalline powders were successfully derived with chemical homogeneity and superior thermal stability, compared with the single component oxides. The particle size and morphology, surface area, and thermal and phase stabilities were characterized using TEM, TG-DTA, BET and XRD. The sensing tests showed that the Sn-In com-posites exhibit high sensitivity and selectivity for CO and NO2. The introduction of TiO2 enhanced CH4 sensitivity and selectivity, particularly, additives of Pd and Al2O3 as a dopant and surface modification greatly enhanced the sensing properties. The sensitivity depended on the composition of composites, calcination temperature and operating temperature. The optimal values were (25%In2O3- 75%SnO2)-20%TiO2 for ternary composite, 600 and 300℃, respectively. Temperature-programmed de-sorption (TPD) studies were employed to explain the gas adsorption behavior dis-played by the surface of nanocomposites and X-ray photoelectron spectroscopic (XPS) analysis was used to confirm the electronic interactions existing between oxide components. The sensing mechanism of the nanocomposites was attributed to chemical and electronic synergistic effects.

关键词： SnO2-In2O3-TiO2 nanocomposites CO NO2 CH4 gas sensing

Synthesis of LaFeO_3 catalytic materials and their sensing properties

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science china Chemistry 2009年第12期52卷 2106-2113页

作者： BAI ShouLi,SHI BingJie,MA LiJing,YANG PengCheng,LIU ZhiYong,LI DianQing & CHEN AiFan State Key Laboratory of chemical Resource engineering,college of science,beijing university of chemical technology,beijing 100029,china State Key Laboratory of chemical Resource engineering College of Science Beijing University of Chemical Technology Beijing China

LaFeO3 is a p-type semiconductor catalytic material of perovskite structure (ABO3). Its magnetic and photocatalytic properties have been widely investigated,but the gas sensing properties are seldom reported,especially for toxic and noxious gases of NO2 and CO. The nanocomposites of LaFeO3 and LaFe1-xMgxO3 (x = 0.02,0.04,0.06) were prepared by various methods of the wet chemical process and their exact composition,crystal structures,grain sizes,specific surfaces,morphology and the electronic interaction between components were characterized by EDX,XRD,BET,SEM and XPS analysis. The sensors based on these nanocomposites have been fabricated to examine the sensing responses to gases,and the results show that these sensors exhibited high response to both oxidizing gas (NO2) and reducing gas (CO),and the response was greatly enhanced by the surface modification of MgO. The additive method,amount of additives,and their effects on the LaFeO3 structure and gas response have been analyzed and discussed by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopic (XPS) analysis.

关键词： LaFeO3 NO2 CO sensing properties MgO-modified