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Heat capacity and thermodynamical properties of the crystal of [RE_2(Glu)_2(H_2O)_8](ClO_4)_4·H_2O (RE = Nd, Eu, Dy)

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Science China Chemistry 2009年第7期52卷 862-867页

作者： WU XinMin1, LI Wei1, TAN ZhiCheng2 & QU SongSheng3 1 Department of Chemical Engineering, Beijing Institute of Petro-chemical Technology, Beijing 102617, China 2 Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China 3 College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072, China Department of Chemical Engineering Beijing Institute of Petro-chemical Technology Beijing China Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian China College of Chemistry and Molecular Science Wuhan University Wuhan China

Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry. However, they have rarely been reported. In this work, a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium, and their thermodynamical data, including the heat capacity in low temperature range and the standard enthalpy of formation, were determined. These complexes were identified to be [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy) by using thermogravimetric analysis (TG), differential thermal analysis (DTA), and chemical and elementary analyses. Their purity has been determined. No melting points were observed for all the three complexes. The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 370 K. Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found. The temperature, enthalpy change and entropy change of the decomposition processes of the three complexes were calculated. The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting. The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at 298.15 K.

关键词： complex of rare earth, [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy Glu = glutamic acid), low-temperature heat capacity, standard enthalpy of formation

Synthesis and crystal structure of complex of Ce(NO_3)_3 with N-(3-methyl-pyridin-2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone

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Science China Chemistry 2004年第3期47卷 251-256页

作者： JIANG Yinzhi1,2 & HU Weixiao1 1. Department of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China 2. Department of Applied Chemistry, Zhejiang Institute of Science and Technology, Hangzhou 310033, China Department of Pharmaceutical Science Zhejiang University of Technology Hangzhou China Department of Applied Chemistry Zhejiang Institute of Science and Technology Hangzhou China

The reaction of 3,6-di-(3-methyl-pyridin-2-yI)-s-tetrazine (DMPTZ, II) with CeIII salt [Ce(NO3)3 · 6H2O] generates a new ligand, N-(3-methyl-pyridin-2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone (L), and forms a new complex: a mononuclear complex [Ce(L)(NO3)2 (H2O)3] · NO3 (III). Crystal data for III: space group P-1, with a = 0.7133(4) nm, b = 1.1139(2) nm, c = 1.4572(3) nm, α= 102.13(2)°, β= 99.81(3)°, γ= 91.10(3)°, Z = 2, V = 1113.6(7) nm3, μ = 2.123 mm?1 and F(000) = 630. L acts as a tri-dentate chelating ligand in III. There are 10 coordination sites around Ce3+ of III, which are respectively occupied by seven oxygen atoms (four from two nitrate anions and three from three H2O molecules) and three nitrogen atoms (all from L). The cerium atom and three chelating nitrogen atoms are coplanar. The mechanism of the metal assisted decomposition is discussed briefly.

关键词： rare earth, complex, crystal structure, synthesize, 3,6-bis (3-methyl-pyridin-2-yl)-s-tetrazine, N-(3-methyl-pyridin- 2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone.

Digital forestry research in China

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Science China(Technological Sciences) 2006年第z1期49卷 1-8页

作者： TANG Shouzheng, TANG Una, Guofan Shao & DAI Limin Research Institute of Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091, China Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Departmet of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA Graduate University, Chinese Academy of Sciences, Beijing 100101, China Research Institute of Resource Information Techniques Chinese Academy of Forestry Beijing 100091 China

Digital Forestry as a concept was developed after the Digital earth program. The Chinese scientists were not only among the pioneers who first proposed the concept of Digital Forestry, but also contributed a lot to the development of Digital Forestry. Digital Forestry is a digital framework to maintain forest planting, management, using, and protect. The synergetic use of computationally-intensive quantitative methods together with information technologies is the most important foundation for the development of Digital Forestry. Under this situation, the experience of Digital Forestry development in China is relatively rich. A number of academicians, scholars, and professional administrators were involved in discussing the Digital Forestry Construction Scheme. The Project of Digital Forestry Practicability approved by the State Forestry Administration is a major instance in developing Digital Forestry standard and key techniques. By introducing a case study of Digital Forestry, this paper reviews the concept of Digital Forestry, the way turning traditional forestry into Digital Forestry, and the future development of Digital Forestry.

关键词： Digital Forest, Digital earth, Digital Forestry standard, Digital Forestry techniques.

Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu_4FeAlCO_3

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Science China Chemistry 2005年第6期48卷 530-537页

作者： CHEN Chunxia1,2, XU Chenghua1, FENG Liangrong1, SUO Jishuan1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China

The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hy-droxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2O2 1/2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 120 min, 10 mL distilled water as solvent. Moreover, a kinetic equation of v = k[La ? Cu 4 FeAlCO 3 ][C 6 H 5 OH][H 2 O 2]. and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is pro-posed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

关键词： rare earth, hydrotalcite, microwave irradiation, phenol hydroxylation, kinetics, reaction mechanism.

Star hexacarboxylate:synthesis,crystal structure and luminescent properties of its terbium complex

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Science China Chemistry 2003年第6期46卷 558-566页

作者：杨迟黄永德陈小明崔英德杨燕生 Faculty of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510090 China Department of Chemistry The University of Hong KongPokfulam RoadHong KongChina Department of Chemistry Zhongshan UniversityGuangzhou 510275 China Zhongkai Agrotechnical College Guangzhou 510225 China

A new star host, hexakis (carboxylphenyl-2-thiolmethyl)benzene (1H6), has been synthesized by a simple one-step condensation procedure with the high yield. Crystal structure of the DMSO adduct 1H6·6DMSO (2) reveals it to be rhombohedral crystal system, space group R-3, with a = b = 2.4129(2), c = 1.1576(3) nm, α= β = 90°, γ= 120°, ∨= 5.837(2) nm3, Z = 3. The six arms of side benzoic acid rings and the H-bonded DMSO molecules are located alternatively above and below the central benzene plane with “1,3,5-up/2,4,6-down” conformation. Terbium complex (Tb21)2Py·9H2O (3) was prepared in hot pyridine, which shows bright characterized Tb(III) emission with a longer lifetime and higher luminescent intensity than that of the corresponding terbium benzoate in solid state. These observations suggest that host 1 is a good antenna for sensitizing TbIII emission.

关键词： hexakis-substituted benzene, star host, polythiolether polycarboxylate, rare earth, luminescence.

La_2Ti_6O_(15)-CeTi_(21)O_(38)-PbTiO_3 ceramics formed in gaseous penetration of La-Ce into PbTiO_3 and their electric properties

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Science China Chemistry 2003年第3期46卷 313-319页

作者：郝素娥韦永德刘新荣 Department of Applied Chemistry Harbin Institute of Technology

The gaseous penetration of La-Ce into PbTiO3 ceramics is reported. The compounds of La2Ti6O15 and CeTi21O38 are formed and the new La2Ti6O15-CeTi21O38-PbTiO3 ceramics are prepared by the penetration of La and Ce in the gaseous state. The new ceramic materials have a significant change in electric properties. The room temperature resistivity decreases from 2.0×1010 to 0.248 Ω. m, and the grain resistance exhibits an obvious PTCR effect with the change of temperature. However, the grain boundary resistance decreases rapidly with increase in temperature. The change rule of the total resistance is similar to that of the grain boundary, and the PTCR effect disappears and the tendency of transition to a conductive body is manifest. The XPS analysis suggests that the particles that are Pb, Ti, La and Ce in La2Ti6O15-CeTi21O38-PbTiO3 ceramics all change their valence and lead to decreasing resistivity, and the bound energy peak values of elements in La2Ti6O15-CeTi21O38-PbTiO3 ceramics are also reported. The La2Ti6O15-CeTi21O38-PbTiO3 ceramics have a better thermal stability in high temperatures through TG-DTA analysis.

关键词： rare earth, PbTiO3 ceramics, gaseous penetration, electric properties, La2Ti6O15, CeTi21O38.

SPACE CHEMISTRY RESEARCHES IN CHINA DURING 2000-2001

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空间科学学报 2002年第Z1期22卷 120-128页

作者： ZOU Yongliao LIN Yangting LI Chunlai LIU Jianzhong OUYANG Ziyuan XU Lin National Astronomical Observatory The Chinese Academy of Sciences Beijing 100012P. R. China Institute of Geochemistry The Chinese Academy of Sciences P.R. China Guangzhou Institute of Geochemistry The Chinese Academy of Sciences P.R. China National Astronomical Observatory The Chinese Academy of Sciences Beijing 100012P. R. China National Astronomical Observatory The Chinese Academy of Sciences Beijing 100012P. R. China Institute of Geochemistry The Chinese Academy of Sciences P.R. China National Astronomical Observatory The Chinese Academy of Sciences Beijing 100012P. R. China Institute of Geochemistry The Chinese Academy of Sciences P.R. China

Over the past two years, significant progress in space chemistry has been made in China. The research fields include meteorites, pre-solar materials, science researches of the moon, effects of the space debris on space environment, and heterogeneity of the earth. Chinese Lunar Exploration Project Some studies are also dedicated to one important space mission "Chinese Lunar Exploration Project". In this paper, the main achievements are outlined, and some concepts and hypotheses are briefly revised.

关键词： Space chemistry, Meteorite, Solar system, earth, Lunar explo ration