Now showing items 1374-1393 of 14235

    • Ba-La-O-(F)催化剂的碱性及其OCM反应性能 

      翁维正; 陈明树; 万惠霖; 方智敏 (2000-04-15)
      采用 XRD,TPD和高温原位 IR光谱对 La2 O3,Ba O/La2 O3,Ba F2 /La2 O3,La OF和 Ba F2 /La OF等催化剂的组成、结构和 CO2 在催化剂上的吸附状况进行了表征 ,并结合催化剂性能评价结果对该系列催化剂的碱性及其与 OCM反应性能的关系进行了考察 .结果表明 ,催化剂 OCM反应性能与其酸碱性的强弱无简单的对应关系
    • (Ba_(0.9)Sr_(0.1))(Ti_(0.999)Nb_(0.001))O_3陶瓷晶粒生长的动力学因子 

      熊兆贤; 冼定国(香港理工大学应用物理系); Baba-KishiKZ(香港理工大学应用物理系) (中国硅酸盐学会, 2001-04)
      [中文文摘]研究了半导化 (Ba0 .9Sr0 .1 ) (Ti0 .999Nb0 .0 0 1 )O3 陶瓷晶粒生长的动力学因子 ,采用固相反应法工艺制备该陶瓷样品 ,化学原材料为纯度高于 99%的BaCO3,SrCO3,TiO2 和Nb2 O5 等 ,并用到微量原料Al2 O3 和MnSiO3 以改善陶瓷的电学性能 .同样化学配方的 8种样品在130 0℃中保温时间分别为 1,3,6 ,10 ,30 ,6 0 ,10 0和 30 ...
    • BaAl_(12)O_(19)高温热稳定材料制备方法 

      陈笃慧; 杨乐夫 (1997)
      bAAl12O19是一种被用于高温催化燃烧的β-Al2O3型材料.在其制备过程中可采用柠檬酸盐无定形前驱体法.它在130℃的分解反映出硝酸盐与自由羰基的相互作用;360℃的分解对应于柠檬酸盐的氧化;在800℃时,bACO3分解并生成bAAl2O4.bAAl2O4的产生并没有抑制bAAl12O19的形成.形成bAAl12O19的另一条途径是γ-Al2O3同分散相bA2+之间的反应
    • Backbone modification promotes peroxidase activity of G-quadruplex-based DNAzyme 

      Li, Cong; Zhu, Ling; Zhu, Zhi; Fu, Hao; Jenkins, Gareth; Wang, Chunming; Zou, Yuan; Lu, Xin; Yang, Chaoyong James; 朱志; 杨朝勇 (CHEM COMMUN, 2012)
      In this work we studied how backbone chemical modifications, such as 2'-O-methyl, phosphorothioate, L-form nucleotides and locked nucleic acid, on G-quadruplex based DNAzymes would affect their peroxidase activity. Our ...
    • Backbone-modified molecular beacons for highly sensitive and selective detection of microRNAs based on duplex specific nuclease signal amplification 

      Lin, Xiaoyan; Zhang, Cheng; Huang, Yishun; Zhu, Zhi; Chen, Xi; Yang, Chaoyong James; 朱志; 陈曦; 杨朝勇 (ROYAL SOC CHEMISTRY, 2013)
      Based on backbone-modified molecular beacons and duplex-specific nuclease, we have developed a target recycling amplification method for highly sensitive and selective miRNA detection. The combination of a low fluorescence ...
    • Bacterial Community Dynamics During Treatment of Anthraquinone Dye in a Hydrolytic Reactor, an Aerobic Biofilm Reactor, and a Combined Hydrolytic-Aerobic Reactor System 

      Wang, Yuanpeng; Zhu, Kang; Dong, Guowen; Wang, Haitao; Liu, Zhenggui; He, Ning; 何宁; Li, Qingbiao; 李清彪; Ren, Nanqi(Harbin Inst Technol, State Key Lab Urban Water Resource & Environm) (MARY ANN LIEBERT INC, 2011-12-30)
      Synthetic dyes are extensively used in industrial processes but do not degrade easily in the environment. Microbial decomposition is a cost-effective alternative to chemical and physical degradation processes. In the present ...
    • BaF_2/La_2O_3催化剂上甲烷氧化偶联反应活性氧物种的原位红外光谱 

      王丽华; 伊晓东; 翁维正; 万惠霖 (2007-09-15)
      用原位红外光谱研究了BaF2/La2O3催化剂上甲烷氧化偶联反应的活性氧物种.结果表明,催化剂经O2预吸附后,在1 108~1 118 cm-1处出现超氧物种O2-的O-O键伸缩振动峰.经18O2同位素交换实验后,原1 108~1 118 cm-1处谱峰的强度减弱,同时在1 086和1 051 cm-1处出现(O18O)-物种和18O2-物种的吸收峰.同位素交换实验进一步确证了1 108~1 118cm-1处谱峰确为O2-物种的吸收峰. ...
    • Bare phosphorus and binary phosphide cluster ions generated by laser ablation 

      Liu, ZY; Huang, RB; 黄荣彬; Zheng, LS; 郑兰荪 (SPRINGER VERLAG, 1996)
      Both positive and negative phosphorus duster ions were generated from the laser ablation of a red phosphorus sample. The mass distribution of phosphorus cluster ions was found to be very sensitive to the power density of ...
    • Barium pyrovanadate prepared from thermal decomposition of barium dimeric(citrato) oxovanadium(IV) 

      Zhou, ZH; 周朝晖; Miao, JY; 缪建英; Zhang, H; 章慧; Wan, HL; 万惠霖 (HIGHER EDUCATION PRESS, 1999)
      Barium dimeric(citrato)oxovanadium(IV) tetrahydrates Ba-2 [VOcit)](2) . 4H(2)O has been prepared by the reaction of sodium dimeric (citrato)oxovanadium (IV) and barium chloride, Its single crystal was obtained by diffusion ...
    • Barnase在大肠杆菌中的分泌表达和诱导条件优化 

      林中叶; 谢友坪; 敬科举; 凌雪萍; 卢英华 (2008-09-30)
      从解淀粉芽孢杆菌中PCR分别扩增解淀粉芽孢杆菌核糖核酸酶barnase基因及其抑制剂barstar基因,采用将barnase基因置于barstar基因保护下的克隆策略,以pET-22b(+)质粒为基础,构建大肠杆菌分泌型表达质粒.IPTG诱导表达目的蛋白后将培养基蛋白进行SDS-PAGE分析并从诱导温度、IPTG诱导浓度和诱导时间三方面初步优化诱导表达条件.
    • Barriers of hydrogen abstraction vs halogen exchange: An experimental manifestation of charge-shift bonding 

      Philippe C. Hiberty; Claire Megret; Song, Lingchun; Wu, Wei; 吴炜; Sason Shaik (AMER CHEMICAL SOC, 2006-02)
      This paper shows that the differences between the barriers of the halogen exchange reactions, in the H + XH systems, and the hydrogen abstraction reactions, in the X + HX systems (X = F, Cl, Br), measure the covalent-ionic ...
    • Base- Catalyzed N similar to N Bond Cleavage of Hydrazones: Synthesis of a- Amino Ketones 

      Tang, Hai-Tao; Zhou, Yun-Bing; Zhu, Yu; Sun, Hong-Chao; Lin, Min; Zhan, Zhuang-Ping; 詹庄平 (WILEY-V C H VERLAG GMBH, 2014 MAY)
      An efficient Cs2CO3-promoted synthesis of -amino ketones using hydrazines, aldehydes, and -haloketones as starting materials through a cascade condensation/nucleophilic substitution/NN bond cleavage route is developed. The ...
    • Base-catalyzed N -N bond cleavage of hydrazones: Synthesis of α-amino ketones 

      Tang, Hai-Tao; Zhou, Yun-Bing; Zhu, Yu; Sun, Hong-Chao; Lin, Min; Zhan, Zhuang-Ping; 林敏; 詹庄平 (WILEY-V C H VERLAG GMBH, 2014 May)
      An efficient Cs2CO3-promoted synthesis of α-amino ketones using hydrazines, aldehydes, and α-haloketones as starting materials through a cascade condensation/nucleophilic substitution/N -N bond cleavage route is developed. ...
    • Base-free aerobic oxidation of 5-hydroxymethyl-furfural to 2,5-furandicarboxylic acid in water catalyzed by functionalized carbon nanotube-supported au-pd alloy nanoparticles 

      Wan, Xiaoyue; Zhou, Chunmei; Chen, Jiashu; Deng, Weiping; Zhang, Qinghong; Yang, Yanhui; Wang, Ye; 邓卫平; 张庆红; 王野 (AMER CHEMICAL SOC, 2014 July )
      The aerobic oxidation of 5-hydroxymethylfurfural (HMF), a key platform compound in cellulose transformation, into 2,5-furandicarboxylic acid (FDCA), a promising renewable alternative to petroleum-derived terephthalic acid, ...
    • Base-promoted reaction of C60Cl6 with thioamides: an access to [60] fullereno[1,9-d] thiazoles 

      Ping Yan; Cheng-Bo Tian; Cong-Li Gao; Qianyan Zhang; Zhuang-Ping Zhan; 詹庄平; Su-Yuan Xie; 谢素原; Min Lin; 林敏; Rong-Bin Huang; 黄荣彬; Lan-Sun Zheng; 郑兰荪 (PERGAMON-ELSEVIER SCIENCE LTD, 2014-09-23)
      Regioselective reaction of C60Cl6 with thioamides via a radical annulation to form fullereno thiazole derivatives is reported. The reaction is promoted by K2CO3, which might deprotonate thioamide to initiate a single ...
    • Basicity of Ba-La-O-(F) catalysts and their catalytic performances for the OCM reaction 

      Weng, WZ; 翁维正; Chen, MS; 陈明树; Wan, HL; 万惠霖; Fang, ZM; 方智敏 (HIGHER EDUCATION PRESS, 2000)
      The structure and surface basicity of a series of lanthanum based catalysts (La2O3, BaO/La2O3, BaF2/La2O3, LaOF, BaF2/LaOF) were characterized by XRD, CO2-TPD and high temperature in situ FTIR spectroscopy of CO2 adsorption. ...
    • Basis set dependence of the doubly hybrid XYG3 functional 

      Zhang, Igor Ying; Luo, Yi(Royal Inst Technol, Sch Biotechnol, Dept Theoret Chem); Xu, Xin; 徐昕 (AMER INST PHYSICS, 2010-09)
      In the present study, we investigated the basis set dependence of XYG3, a newly developed doubly hybrid functional [Y. Zhang, X. Xu, and W. A. Goddard III, Proc. Natl. Acad. Sci. U.S.A. 106, 4963 (2009)], in prediction of ...
    • Beauty, Symmetry, and Magnetocaloric Effect-Four-Shell Keplerates with 104 Lanthanide Atoms 

      Jun-Bo Peng; 彭军波; Xiang-Jian Kong; 孔祥建; Qian-Chong Zhang; 张庆红; Martin Orendáč ( Safarik Univ, Fac Sci, Ctr Low Temp Phys, Kosice 04154, Slovakia and Inst Expt Phys SAS, Kosice 04154, Slovakia); Jan Prokleška ( Charles Univ Prague, Fac Math & Phys, Dept Condensed Matter Phys, CZ-12116 Prague 2, Czech Republic); Yan-Ping Ren; 任艳萍; La-Sheng Long; 龙腊生; Zhiping Zheng; 郑智平; Lan-Sun Zheng; 郑兰荪 (AMER CHEMICAL SOC, 2014-12-31)
      The hydrolysis of Ln(ClO4)(3) in the presence of acetate leads to the assembly of the three largest known lanthanide-exclusive cluster complexes, [Nd-104(ClO4)(6)(CH3COO)(60)(mu(3)-OH)(168)(mu(4)-O)(30)(H2O)(112)].(ClO4) ...
    • Behavior of active sites on Cr-MCM-41 catalysts during the dehydrogenation of propane with CO2 

      TAKEHIRA, K; OHISHI, Y; SHISHIDO, T; KAWABATA, T; TAKAKI, K; ZHANG, QH; WANG, Y; 王野 (2004-06-10)
      M-MCM-41 catalysts (M: V, Cr, Mn, Fe, Co, Ni, and Ga) prepared by direct hydrothermal (DHT) synthesis have been tested for dehydrogenation of propane with carbon dioxide. The synthesized materials were characterized by ...
    • BEHAVIOR OF QUENCHING OF PYRENE FLUORESCENCE BY ALKYLBENZYLAMMONIUM IN AQUEOUS SOLUTION 

      Jiang, Y. B.; Xu, J. O.; 江云宝 (1992)
      The quenchings of pyrene fluorescence were studied with tetradecylbenzyldime, thylammonium chloride (Zeph) and benzyltrimethylammonium bromide (TMBA) through their Stern Volmer plots. Transient and steady state fluorescence ...