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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

Depth profiling of SBS/PET layered materials using step-scan phase modulation Fourier transform infrared photoacoustic spectroscopy and two-dimensional correlation analysis

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Science China Chemistry 2010年第5期53卷 1189-1193页

作者： LI BoBin & ZHANG PuDun State Key Laboratory of chemical Resource Engineering beijing university of chemical technology,beijing 100029,China 1. State Key Laboratory of chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

This paper demonstrates the application of step-scan phase modulation Fourier transform infrared photoacoustic spectroscopy(FTIR-PAS) in non-destructively depth profiling of styrene-butadiene-styrene block copolymer/polyethylene terephthalate(SBS/PET) layered *** surface thicknesses of three layered samples were determined to be 1.2,4.3 and 9.4μm by using phase difference analysis,overcoming the spatial detection limits of *** with generalized two-dimensional(G2D) FTIR correlation analysis,the spatial origins of peaks in the SBS/PET spectrum are identified with those having overlapping peaks between different layers are resolved.

关键词： depth profiling FTIR photoacoustic step-scan two-dimensional correlation analysis layered materials

Controlling Pore Size and its Distribution of γ-Al_2O_3 Nanofiltration Membranes

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Chinese chemical Letters 2003年第9期14卷 969-972页

作者： Rong Chun XIONG, Xiao Dong LEI, Gang WEI beijing university of chemical technology, beijing 100029 beijing Univ. of chemical technology Beijing 100029 China

The preparation process of γ-A12O3 nanofiltration membranes were studied by N2 absorption and desorption test and retention rate vs thickness gradient curve method. It was found that template and thermal treatment were key factors for controlling pore size and its distribution. Under the optimized experimental conditions, the BJH (Barret-Joyner-Halenda) desorption average pore diameter, BJH desorption cumulative volume of pores and BET (Brunauer-Emmett-Teller) surface area of obtained membranes were about 3.9 nm, 0.33 cm3/g and 245 m2/g respectively, the pore size distribution was very narrow. Pore size decreased with the increasing of thickness and no evident change after the dense top layer was formed. The optimum thickness can be controlled by retention rate vs thickness gradient curve method.

关键词： Nanofiltration γ-Al2O3 membrane membrane pore size N2 absorption-desorption test.

Engineering of drug nanoparticles by HGCP for pharmaceutical applications

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Particuology 2008年第4期6卷 239-251页

作者： Ting-Ting Hua, Jie-Xin Wanga, Zhi-Gang Shena, Jian-Feng Chena,b, a Key Lab for Nanomaterials, Ministry of Education, beijing university of chemical technology, beijing 100029, China b Research Center of Ministry of Education for High Gravity Engineering and technology, beijing university of chemical technology, beijing 100029, China [a] Key Lab for Nanomaterials Ministry of Education Beijing University of Chemical Technology Beijing 100029 China [b] Research Center of Ministry of Education for High Gravity Engineering and technology Beijing University of Chemical Technology Beijing 100029 China

This paper reviews our work on the fundamental principles of high gravity controlled precipitation (HGCP) technology, and its applications in the production of drug nanoparticles, which was carried out in a rotating packed bed (RPB). Several kinds of drug nanoparticles with narrow particle size distributions (PSDs) were successfully prepared via HGCP, including the 300-nm Cefuroxime Axetil (CFA) particles, 200–400-nm cephradine particles, 500-nm salbutamol sulfate (SS) particles (100 nm in width), and 850-nm beclomethasone dipropionate (BDP) particles, etc. Compared to drugs available in the current market, all the drug nanoparticles produced by HGCP exhibited advantages in both formulation and drug delivery, thus improving the bioavailability of drugs. HGCP is essentially a platform technology for the preparation of poorly water-soluble drug nanoparticles for oral and injection delivery, and of inhalable drugs for pulmonary delivery. Consequently, HGCP offers potential applications in the pharmaceutical industry due to its cost-effectiveness, efficient processing and the ease of scaling-up.

关键词： High gravity controlled precipitation Rotating packed bed Drug nanoparticle Poorly water-soluble drug Inhalable drug

Study on the Miscibility and Phase Behavior of Polyoxymethylene with Novolak

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Journal of Materials Science & technology 2000年第4期16卷 427-430页

作者： Xiaodong WANG, Hangquan LI and Riguang JIN (School of Materials Science and Engineering, beijing university of chemical technology, beijing 100029, China) School of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

The miscibility and phase behavior of the blends of polyoxymethylene (POM)/Novolak were investigated by the cloud point method, which showed that the POM/Novolak blends exhibited a lower critical solution temperature. The melting point of POM decreased when diluted with Novolak. From the melting temperature depression of POM, a negative interaction parameter (x) between POM and Novolak was obtained. The IR spectrum revealed that the miscibility between POM and Novolak was caused by the specific interaction between the OH groups of Novolak and the ether oxygen atoms of POM. The morphology of the blends investigated by polarized light microscopy showed that the size of spherulites of POM was sharply decreased by its mixing with Novolak. This suggests that Novolak be used as a compatibilizer for POM.

关键词： POM Study on the Miscibility and Phase Behavior of Polyoxymethylene with Novolak

Statistical Characteristics of Metastable Pitting of 316 Stainless Steel

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Journal of Materials Science & technology 2000年第3期16卷 286-290页

作者： Yu ZUO, Haiou DU and Jinping XIONG (Dept. of Applied Chemistry, beijing university of chemical technology, beijing 100029, China) Dept. of Applied Chemistry Beijing University of Chemical Technology Beijing 100029 China

The statistical characteristics of the current fluctuations during metastable pitting of 316L stainless steel in NaCI solution were studied using potentiostatic method. The growth rates and peak currents of metastable pits followed log-normal distributions. As potential and chloride concentration increased, both growth rate and peak current of metastable pits increased. The lifetime of metastable pits also followed log-normal distribution, and was almost not affected by potential. Higher growth rates did not definitely result in larger metastable pits. A certain propagation rate range was found beneficial for the micropit to remain growth. At constant potential, the maximum peak currents in different time intervals during a potentiostatic test followed extreme distribution. The statistical characteristics of metastable pitting may be used to predict the tendency of pitting corrosion.

关键词： Statistical Characteristics of Metastable Pitting of 316 Stainless Steel

ESTIMATION OF ATOMIC CHARGE IN NEUTRAL MOLECULES

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Chinese chemical Letters 1995年第4期6卷 317-320页

作者： Qian Ji LI Zuo Xin WANG(beijing university of chemical technology, beijing 100029) beijing Univ Chem Technol Beijing 100029 Peoples R China

An empirical method is proposed to estimate atomic charge for electrical neutral molecules containing multi-centers or groups. The harmonic mean is adopted and extended to estimate the electron density distribution of this kind of molecules. The results show that the data calculated not only are consistent with the principle of electronegativity equalization, but also more reasonable. Why organic acids are stronger than organic alcohols in acidity has been discussed on the basis of calculated partial charges.

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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

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

Preparation of (Ti, Sn)O_2 Nano-Composite Photocatalyst by Supercritical Fluid Dry Combination technology

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Journal of Materials Science & technology 2005年第2期21卷 191-195页

作者： Jingchang ZHANG, Qing LI and Weiliang CAO Institute of Modern Catalysis, The Key Laboratory of Science and technology of Controllable chemical Reactions, Ministry of Education, beijing university of chemical technology, beijing 100029, China Lab. of Controllable Chem. Reactions Inst. of Modern Catalysis Beijing Univ. of Chem. Technol. Beijing 100029 China

A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology. Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0-4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (Ti, Sn)O2 were investigated and its catalytic mechanism was proposed. The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size, large surface area and high activity.

关键词： Anatase TiO2 (Ti, Sn)O2 Photo-catalytic Supercritical fluid dry method Solid-phase reaction