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Effects of Oxalic Acid Addition on the Hydrothermal Synthesis of Kaolinite

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Journal of Central South university 2000年第1期12卷 34-36页

作者： LIU Su qin,HUANG Ke long (college of chemistry and chemical engineering, Central South university of Technology, Changsha 410083, china) college of chemistry and chemical engineering Central South University of Technology Changsha China

Kaolinite was hydrothermally synthesized from alumina gel and silicate by dissolving alumina gel in oxalic acid before it was mixed with silicate, effects of the amount of addition on the species of synthetic products were discussed. The reaction product was characterized by X ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that analcite is the only phase of the reaction solution without oxalic acid, the proportion of kaolinite in product increases with the amount of addition, and kaolinite is the main species when the molar ratio of oxalic acid to alumina reaches 0.6∶1.0. This is because oxalic acid addition is beneficial to the formation of kaolinite through changing the coordination number of aluminium from four to six, while the mixture of alumina gel, before it was dissolved in oxalic acid with silicate interfered with the crystallization of kaolinite.

关键词： kaolinite hydrothermal synthesis oxalic acid

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

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Science china(Technological Sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2, LIU GuoQuan2, LI ZhiLin3, FENG ChengMing1 1 Mechanical and Electronic engineering college, Shandong Agricultural university, Tai’an 271018, china 2 college of Materials Science and engineering, university of Science and Technology, Beijing 100083, china 3 college of Material Science and engineering, Beijing university of chemical Technology, Beijing 100029, china Mechanical and Electronic engineering college Shandong Agricultural University Tai’an China college of Materials Science and engineering University of Science and Technology Beijing China college of Material Science and engineering Beijing University of Chemical Technology Beijing China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

Caspase Family Proteases and Apoptosis

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Acta Biochimica et Biophysica Sinica 2005年第11期37卷 719-727页

作者： Ting-Jun FAN Li-Hui HAN Ri-Shan CONG Jin LIANG college of Marine Life Sciences,Division of Life Science and Technology,Ocean university of china,Qingdao 266003,china college of chemistry & chemical engineering,Ocean university of china,Qingdao 266003,china college of Marine Life Sciences Division of Life Science and Technology Ocean University of ChinaQingdao 266003 China college of chemistry & chemical engineering Ocean University of ChinaQingdao 266003 China

Apoptosis,or programmed cell death,is an essential physiological process that plays a criticalrole in development and tissue *** progress of apoptosis is regulated in an orderly way by aseries of signal cascades under certain *** caspase-cascade system plays vital roles in theinduction,transduction and amplification of intracellular apoptotic ***,closely associated withapoptosis,are aspartate-specific cysteine proteases and members of the interleukin-1β-converting *** activation and function of caspases,involved in the delicate caspase-cascade system,are regu-lated by various kinds of molecules,such as the inhibitor of apoptosis protein,Bcl-2 family proteins,calpain,and Ca2+,Based on the latest research,the members of the caspase family,caspase-cascade system andcaspase-regulating molecules involved in apoptosis are reviewed.

关键词： caspase apoptosis interleukin-1β-converting enzyme family inhibitor of apoptosis protein Bcl-2 family

Preparation of TiO_2/activated carbon with Fe ions doping photocatalyst and its application to photocatalytic degradation of reactive brilliant red K2G

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Science china chemistry 2009年第8期52卷 1113-1119页

作者： LI YouJi,LI Jing,MA MingYuan,OUYANG YuZhu & YAN WenBin college of chemistry and chemical engineering,Jishou university,Jishou 416000,china college of chemistry and chemical engineering Jishou University Jishou China

Titanium dioxide coated on activated carbon(AC) with Fe ions doping(Fe-TiO2/AC) composite was prepared by an improved sol-gel *** photocatalytic activities were tested by photocatalytic degradation of reactive brilliant red K2G in *** results show that in comparison with the agglomeration of pure TiO2,the TiO2 nanoparticles are well dispersed in the AC matrix,of which sizes are decreased with Fe ions ***,the iron species on TiO2 of composite are Fe2O3 and FeO,which do not affect the crystalline structures of TiO2 *** AC matrix and iron doping content influence the fluorescence intensity of composite due to their effects on recombination probability of hole-electron *** with TiO2,0.3% Fe-TiO2,TiO2/AC,0.5% Fe-TiO2/AC and 0.1% Fe-TiO2/AC,the 0.3% Fe-TiO2/AC shows the highest photoactivity with the complete mineralization of K2G for finite time due to the optimum Fe ions content and AC ***,the kinetic constant(k=0.0229 min-1) of 0.3% Fe-TiO2/AC composite is more than the sum of both TiO2/AC(0.0154 min-1) and 0.3% Fe-TiO2(0.0057 min-1) because coexistence of the AC and Fe ions has an enlarging effect on improving the photoactivity of TiO2.

关键词： TiO2 nanoparticles Fe ions activated carbon photocatalysis reactive brilliant red K2G

Supramolecular self-assembly and controllable drug release of thermosensitive hyperbranched multiarm copolymers

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Science china chemistry 2010年第3期53卷 487-494页

作者： GUO Bo,SUN XiaoYi,ZHOU YongFeng & YAN DeYue college of chemistry and chemical engineering,Shanghai Jiao Tong university,Shanghai 200240,china college of chemistry and chemical engineering Shanghai Jiao Tong University Shanghai China

A novel temperature-responsive hyperbranched multiarm copolymer with a hydrophobic hyperbranched poly(3-ethyl-3-(hydroxymethyl)oxetane)(HBPO) core and thermosensitive poly(N-isopropylacrylamide)(PNIPAM) arms was synthesized via the atom transfer radical polymerization(ATRP) of NIPAM monomers from a hyperbranched HBPO *** was found that HBPO-star-PNIPAM self-assembled into multimolecular micelles(around 60 nm) in water at room temperature according to pyrene probe fluorescence spectrometry,1H NMR,TEM,and DLS *** micelle solution showed a reversible thermosensitive phase transition at a lower critical solution temperature(LCST)(around 32°C) observed by variable temperature optical absorbance *** temperature NMR and DLS analyses demonstrated that the LCST transition originated from the secondary aggregation of the micelles driven by increasing hydrophobic interaction due to the dehydration of PNIPAM shells upon *** drug loading and release properties of HBPO-star-PNIPAM micelles were also investigated using prednisone acetate as a model *** micelles showed a much improved drug encapsulation efficiency and temperature-dependent sustainable release behavior due to the special micellar *** micelles exhibited no apparent cytotoxicity against human HeLa cells.

关键词： hyperbranched polymers thermosensitive copolymer supramolecular self-assembly ATRP drug delivery

An efficient chiral synthesis of (R)-N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

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Science china chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2 & TANG XinLiang1,3 1 Technical Institute of Physics and chemistry,Chinese Academy of Sciences,Beijing 100080,china 2 college of chemistry and chemical engineering,Graduate university of Chinese Academy of Sciences,Beijing 100049,china 3 School of chemical engineering and Environment,Beijing Institute of Technology,Beijing 100081,china Technical Institute of Physics and chemistry Chinese Academy of Sciences Beijing China college of chemistry and chemical engineering Graduate University of Chinese Academy of Sciences Beijing China School of chemical engineering and Environment Beijing Institute of Technology Beijing China

R-Enantiomer of the β-receptor antagonist N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13C NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

Influence of steric and intramolecular inductive effects on the variable trends in R-X (R=Alkyl) bond dissociation energy

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Science china chemistry 2009年第7期52卷 943-951页

作者： CAO ChenZhong School of chemistry and chemical engineering, Hunan university of Science and Technology, Xiangtan 411201, china School of chemistry and chemical engineering Hunan University of Science and Technology Xiangtan China

The question "why are the variation trends of R-X bond dissociation energy different?" is answered. The R-X bond dissociation energy (BDE) may be influenced by three main factors: the C-X intrinsic bond energy, the 1,3 geminal repulsion, and the intramolecular charge-induced dipole. In the presence of atom X, the variation trend of BDE in R-X (R= Me, Et, i-Pr, t-Bu) is dominated by two factors, the 1,3 geminal repulsion and the intramolecular charge-induced dipole. The former decreases the R-X BDE, and the latter either increases or decreases the R-X BDE. For the series of R-X with the R-C bond (such as R-Me, R-CH == CH2, R-C≡CH, and R-CN), the 1,3 geminal repulsion decreases the R-X BDE, and the variation trends of R-C BDE decrease from Me to t-Bu. As regards the series of R-X (such as R-H, R-BH2, and R-SiH2) in which the electronegativity of atom X is smaller than that of the carbon atom, the above two factors decrease the R-X BDE, and the variation trends of the R-X BDE decrease from Me to t-Bu. As to the series of R-X (such as R-F, R-OH, R-Cl, R-Br, R-I, and R-NH2) in which the electronegativity of atom X is larger than that of the carbon atom, the 1,3 geminal repulsion decreases the R-X BDE, while the intramolecular charge-induced dipole increases the R-X BDE. In this case, the variation trends of R-X BDE depend on the competition of the two factors. As a result, some of them (e. g., R-F, R-OH) increase from Me to t-Bu, some (e. g., R-I) decrease from Me to t-Bu, and some (e. g., R-Br) change very little.

关键词： bond dissociation energy charge-induced dipole geminal repulsion ionic configuration

Preparation and photocatalytic activity of TiO_2-coated granular activated carbon composites by a molecular adsorption-deposition method

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Science china chemistry 2008年第11期51卷 1036-1043页

作者： LI YouJi, LI Jing, MA MingYuan, OUYANG YuZhu & YAN WenBin college of chemistry and chemical engineering, Jishou university, Jishou 416000, china college of chemistry and chemical engineering Jishou University Jishou China

TiO2 nanoparticle-coated granular activated carbon (GAC) composite photocatalysts (CPs) were suc-cessfully prepared by a molecular adsorption-deposition (MAD) method. The CPs were detected by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), BET surface area and UV-Vis adsorption spectroscopy, and their photoactivity was evaluated by methyl orange (MO) photodegradation. The results show that small-sized TiO2 nanoparticles were dispersed well, deposited on the surface of GAC, and showed slight blue shift in comparison with pure TiO2. With the increase in TiO2 content, the CPs showed band gaps in lower energy, smaller surface areas and the higher content of Ti3+ ions. Compared with pure TiO2 and others CPs samples, CPs-382 sample showed the highest photoactivity due to the optimum TiO2 content and surface area besides the synergic effect of photocatalytic degradation of TiO2 and adsorptive property of GAC. In addition, the CPs could be very easily reclaimed, recycled and reused for methyl orange removal while high photoactivity is pre-served.

关键词： photocatalysis titanium dioxide granular activation carbon composites molecular adsorption–deposition method

Electrochemical behavior of Cu(II) reduced in CH3OH and DMSO

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Rare Metals 2003年第3期22卷 210-214页

作者： SONG Jiguo, SONG Huacan, and YANG QiqinSchool of chemistry and chemical engineering, Zhongshan university, Guangzhou 510275, china School of chemistry and Chemicul engineering Zhongshan University Guangzhou 510275

The cyclic voltammetry and the potential-time curve after galvanostaticelectrolysis were used to study the electrode processes of Cu(II) in CH_3OH solution and DMSOsolution. The electroreduction of Cu(II) to Cu on a Pt electrode proceeds in two steps: Cu(II) + evelence Cu(I); Cu(I) + e velence Cu. The reduction potential of Cu(II) in DMSO solution is morenegative than that in CH_3OH solution, and the diffusion coefficient of Cu(II) ion in DMSO solutionis larger than that in CH_3OH solution because the polarity of DMSO is larger than that of CH_3OHobservably and has a stronger solvating power.

关键词： electrochemistry electroreduction of Cu(II) cyclic voltammetry diffusioncoefficient solvability