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Synergistic Effect in Special Selectivity Mixed Gas Chromatographic Stationary Phase in the Separation of Aromatic Compounds

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Chinese Chemical Letters 1998年第2期9卷 151-155页

作者： Yuan, LM Fu, RN Gui, sh Chen, XX Dai, RJ Yunnan Normal Univ Dept Chem Kunming 650092 Peoples R China Beijing Inst Technol Dept Chem Engn Beijing 100081 Peoples R China Yunnan Normal Univ Solar Energy Res Inst Kunming 650092 Peoples R China

The gas chromatographic separations of aromatic compounds using special mixed stationary phases consisting of pp-beta-CD+AgNO3, pp-beta-CD+TINO3, pp-beta-CD+di-n-butly phthalate, pp-beta-CD+BPBHpB liquid crystalline, and bentone-34+AgNO3 were investigated. Besides pp-beta-CD+di-n-butyl phthalate, most of the separations deviated from the additivity and a synergistic effect was observed. The separation effects depend on the temperature and how mixing is accomplished.

关键词： gas chromatography mixed stationary phase synergistic effect aromatic compounds

SLOW PELLETING COAGULATION OF POLYMER LATEX EMULSION

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Chinese Chemical Letters 1996年第3期7卷 297-298页

作者： Li, YM Chen, MW Xu, GJ Ou, sh Wang, K ZHEJIANG UNIV DEPT POLYMER SCI & ENGNHANGZHOU 310027PEOPLES R CHINA

In this paper, slow pelleting flocculation of polymer latex consisting of butadiene, styrene and methyl methacrylate(MBS) were investigated, using aqueous H2SO4 as coagulant. It is found that spherical particles with uniform particle size and high bulk density were produced in the narrow range of pH. In order to obtain good particle morphology, well-distributed concentration, temperature and shear field in the coagulating system were required. Polymer latex made from emulsion polymerization often needs to be converted into dry powders. Usually, we simply add excessive coagulant, such as inorganic acid, salt, etc., into latex emulsion to make it coagulate. The particles formed with such method always have irregular shape and high fines content. In recent years, more attention has been paid to the method of getting coagulated particles with satisfactory particle morphology(1-3)].

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STUDIES　OF　POLYMER　IMMOBILIZED　Pd－Cu　CLUSTER　CATALYSTS　PREPARED　BY　METAL　ATOM　SYNTHESIS（MVS）

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Chinese Chemical Letters 1995年第1期6卷 71-74页

作者： Wu, sh Zhu, CY Zhu, JL Zheng, XS Nankai Univ Dept Chem Tianjin 300071 Peoples R China

Metal atoms of Pd and Cu produced by coevaporation in a metal atom reactor,was solvated at low temperature. These solvated metal atoms,were immobillized in. the polymer pore structure for preparing Pd-Cu bimetallic cluster *** measurements sbowed that both Pd and Cu,were in a zero-valent state. TEM and XRD resulta indicated that the Pd-Cu cluster particles,were very small. Catalytic tests. showed that these catalysts are very active for 4-methyl-3-penten-2-one hydrogenation.

关键词： Pd IMMOBILIZED CLUSTER ATOM BY MVS Cu

Prediction of yttrium, lanthanum, cerium, and neodymium leaching recovery from apatite concentrate using artificial neural networks

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Journal of University of Science and Technology Beijing 2008年第4期15卷 367-374页

作者： E. Jorjani A.H. Bagherieh sh. Mesroghli S. Chehreh Chelgani Department of Mining Engineering Research and Science Campus Islamic Azad University Poonak Hesarak Tehran Iran

The assay and recovery of rare earth elements （REEs） in the leaching process is being determined using expensive analytical methods： inductively coupled plasma atomic emission spectroscopy （ICP-AES） and inductively coupled plasma mass spectroscopy （ICP-MS）. A neural network model to predict the effects of operational variables on the lanthanum, cerium, yttrium, and neodymium recovery in the leaching of apatite concentrate is presented in this article. The effects of leaching time （10 to 40 min）, pulp densities （30% to 50%）, acid concentrations （20% to 60%）, and agitation rates （100 to 200 r/min）, were investigated and optimized on the recovery of REEs in the laboratory at a leaching temperature of 60℃. The obtained data in the laboratory optimization process were used for training and testing the neural network. The feed-forward artificial neural network with a 4-5-5-1 arrangement was capable of estimating the leaching recovery of REEs. The neural network predicted values were in good agreement with the experimental results. The correlations of R=l in training stages, and R=0.971, 0.952, 0.985, and 0.98 in testing stages were a result of Ce, Nd, La, and Y recovery prediction respectively, and these values were usually acceptable. It was shown that the proposed neural network model accurately reproduced all the effects of the operation variables, and could be used in the simulation of a leaching plant for REEs.

关键词： apatite neural networks rare earth elements leaching recovery

Photochemistry of phenothiazine in benzene and cyclohexane

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Chinese Science Bulletin 1997年第12期42卷 998-1000页

作者： Wang, sh Chen, DW Gou, JX Wang, H Institute of Chemistry Chinese Academy of Sciences Beijing China

IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid production in the presence of vicinal dibromides and hence tochange the solubilization of polymer *** photophysical and photochemical properties re-lated to the processes have been *** Barra et *** that the triplet

关键词： photochemistry ESR nitroxyl radical cation radical.

Age of the shahewan rapakivi granite in the Qinling Orogen, China, and its constraints on the end time of the main erogenic stage of this orogen

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Chinese Science Bulletin 1999年第21期44卷 2001-2004页

作者： Zhang, ZQ Zhang, GW Tang, sh Lu, XX Chinese Acad Geosci Inst Geol Beijing 100037 Peoples R China NW Univ Xian Dept Geol Xian 710069 Peoples R China Dept Geol Res Henan Province Zhengzhou 450053 Peoples R China

the Qinling Mountains in central China are a joint orogenic zone between the Sino-Korean (or North China) and the Yangtze (or South China) craton blocks, the two major tectonic units of eastern Asia. On the end time o... 详细信息

关键词： age rapakivi granite orogenic belt Qinling Mountains.

A New 6,7-Seco-Ent-Kaurane Diterpenoid from Isodon eriocalyx Var. laxiflora

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Chinese Chemical Letters 2001年第10期12卷 897-898页

作者： Niu, XM Li, sh Mei, SX Lin, ZW Sun, HD Acad Sinica Kunming Inst Bot Lab Phytochmistry Kunming 650204 Peoples R China

A new 6,7-seco-ent-kaurane diterpenoid, together with two known ones, was isolated from the leaves of Isodon eriocalyx var. laxiflora C. Y. Wu & H. W. Li. Their structures were established by spectroscopic methods.

关键词： Isodon eriocalyx var. laxiflora 6,7-seco-ent-kaurane diterpenoid laxiflorin E

Influence of Fe on electronic density of defects in NiAl alloys

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Chinese Science Bulletin 1997年第21期42卷 1783-1787页

作者： Deng, W Xiong, LY Wang, sh Guo, JT Long, QW Guangxi Univ Dept Phys Nanning 530004 Peoples R China

NiAl alloy is considered to be a good candidate material for high performance, high-tempera-ture structural applications since this material offers a wide range of attractive mechanical andphysical properties, such as low density (5. 86 g/cm^3), high melting point (1 640℃), goodthermal conductivity (4--8 times compared with Ni-based superalloys) and oxidation resis-tance. However, the use of NiAl is limited by its room-temperature brittleness. Georgeand Liu have investigated the effects of microalloying elements B, C and Be on the fractureproperties and grain boundaries of NiAl alloy. Their results showed that the improvement

关键词： NiAl alloy positron lifetime microdefects electronic density.

Infrared, Diffuse Reflectance and Dielectric Studies ofAntimony Trisulphide

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Journal of Materials Science & Technology 1998年第4期14卷 344-348页

作者： Hanafi, Z.M. Ismail, F.M. Khalil, M.sh. Inorganic Chemistry Dept. National Research Centre Dokki Cairo Egypt

Infrared absorption spectra of orange, black and transferred Sb//2S//3 samples have been studied in the spectral range 200-4000 cm** minus **1. The pronounced difference between the different samples is the appearance of excess sulphur present in the orange and transferred samples except those of transferred at 543 K and the black Sb//2S//3. The change of sharpness of some IR peaks reveals the amorphous/crystalline change. The effect of the degree of crystallinity and stoichiometry on the energy gap values was investigated by using optical method. The obtained dielectric parameters epsilon prime and epsilon double prime of the different samples are thoroughly affected by the degree of crystallinity and smoothly affected by either the frequency or the temperature or both, except at lower frequencies. (Edited author abstract) 26 Refs.

关键词： Antimony compounds