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Flatness of CR submanifolds in a sphere

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Science China Mathematics 2010年第3期53卷 701-718页

作者： JI ShanYu 1, & YUAN Yuan 2 1 Department of Mathematics, university of Houston, Houston, TX 77204, usa 2 Department of Mathematics, Rutgers university, Piscataway, NJ 08854, usa 1. Department of Mathematics University of Houston Houston TX 77204 USA2. Department of Mathematics Rutgers University Piscataway NJ 08854 USA

In Euclidean geometry, for a real submanifold M in E n+a , M is a piece of E n if and only if its second fundamental form is identically zero. In projective geometry, for a complex submanifold M in CP n+a , M is a piece of CP n if and only if its projective second fundamental form is identically zero. In CR geometry, we prove the CR analogue of this fact in this paper.

关键词： CR submanifolds sphere CR second fundamental form proper holomorphic mappings between balls

Bioamendment of petroleum contaminated ultisol:effect on oil content, heavy metals and pH of tropical soil

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Journal of Environmental Sciences 2001年第1期13卷 92-98页

作者： E. D. Udosen 1, J. P. Essien 2, R. M. Ubom 2 (1 Department of chemistry and Biochemistry, university of Uyo, Nigeria 2 Department of Botany and Microbiology, university of Uyo, Nigeria) Department of chemistry and Biochemistry University of Uyo Nigeria.

The effect of organic amendments on the oil content, heavy metals concentration and pH of petroleum contaminated sandy loam ultisol obtained from Rumuekpe oil field in Emohua Local Government Area of Rivers State, Nigeria was determined. Petroleum contaminated soils were treated with wood ash, compost and sawdust. The addition of organic amendments resulted in a significant(at 95% probability level) decrease in oil content by 92% for composting, 81% for soil treated with sawdust and 58% for soil with ash supplementation, over 6 months. The effect of treatments on the iron(Fe), copper(Cu) and lead(Pb) concentration was significant at P 2 and 5 3. On the other hand, amending the soil with wood ash raised the pH from 5 6 to 6 2. Increased acidity caused a decrease in the heavy metals concentration in the contaminated soil. Soil treatment with compost generally gave the best remediation results, followed by sawdust and then ash. Adjusting the pH of oil contaminated soil to high acidic levels may promote the availability and migration of heavy metals in remediated soils and not necessarily the rate of oil mineralization.

关键词： bioamendament tropical soil Nige

Theoretical studies on Ru(fppz)_2(CO)L (L=N-heterocyclic ligand):Electronic structure,absorption,phosphorescence,and solvatochromism

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Science China chemistry 2008年第12期51卷 1211-1220页

作者： LIU Tao1, ZHOU Xin1, BAI FuQuan1, ZHANG JianPo1, XIA BaoHui1,2, PAN QingJiang3 & ZHANG HongXing1 1 State Key Laboratory of Theoretical and Computational chemistry, Institute of Theoretical chemistry, Jilin university, Changchun 130023, China 2 College of chemistry, Jilin university, Changchun 130023, China 3 Laboratory of Physical chemistry, School of chemistry and Materials Science, Heilongjiang university, Harbin 150080, China State Key Laboratory of Theoretical and Computational chemistry Institute of Theoretical Chemistry Jilin University Changchun 130023 China College of chemistry Jilin University Changchun 130023 China Laboratory of Physical chemistry School of Chemistry and Materials Science Heilongjiang University Harbin 150080 China

A series of ruthenium(II) complexes Ru(fppz)2(CO)L [fppz = 3-trifluoromethyl-5(2-pyridyl)pyrazole; L = pyridine (1), 4-dimethylaminopyridine (2), 4-cyanopyridine (3)] were designed and investigated theo-retically to explore their electronic structures, absorption, and emissions as well as the solvatochrom-ism. The singlet ground state and triplet excited state geometries were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO of 1-3 is composed of dyz(Ru) atom and π(fppz). The LUMO of 1 and 2 is dominantly contributed by π*(fppz) orbital, but that of 3 is con-tributed by π*(L). Absorption and phosphorescence in vacuo, C6H12, and CH3CN media were calculated using the TD-DFT level of theory with the PCM model based on the optimized ground and excited state geometries, respectively. The lowest-lying absorption of 1 and 2 at 387 and 391 nm is attributed to {[dyz(Ru) + π(fppz)] → [π*(fppz)]} transition, but that of 3 at 479 nm is assigned to {[dyz(Ru) + π(fppz)] → [π*(L)]} transition. The phosphorescence of 1 and 2 at 436 and 438 nm originates from 3{[dyz(Ru) + π(fppz)] [π*(fppz)]} excited state, while that of 3 at 606 nm is from 3{[dyz(Ru) + π(fppz)] [π*(L)]} excited state. The calculation results showed that the absorption and emission transition character can be changed from MLCT/ILCT to MLCT/LLCT transition by altering the substituent on the L ligand. The phosphorescence of 1 and 2 does not have solvatochromism, but that of 3 at 606 nm (vacuo), 584 nm (C6H12), and 541 nm (CH3CN) is strongly dependent on the solvent polarity, so introducing elec-tron-withdrawing group on ligand L will induce remarkable solvatochromism.

关键词： ruthenium complex DFT phosphorescence solvatochromism

Inhibitory effect of picroside Ⅱ on hepatocyte apoptosis

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Acta Pharmacologica Sinica 2005年第6期26卷 729-736页

作者： Hua GAO, Ya-wei ZHOU~2 College of chemistry and Molecular Engineering, Peking university, Beijing 100871, China College of chemistry and Molecular Engineering Peking University Beijing China

Aim: To investigate the influence of picroside on hepatocyte apoptosis and its mechanism. Methods: Morphological changes and quantification of apoptotic cells were determined under transmission electron microscopy and flow cytometry respectively. DNA fragmentation was visualized by agarose gel electrophoresis. Semi-quantitative reverse transcription-PCR (RT-PCR) was used to analyze the expression of bcl-2 and bax genes. The content of manganese-superoxide dismutase (SOD) in liver mitochondria was detected by the Marland method. The content of malonic aldehyde (MDA) and the protein level in liver tissue were determined by thiobarbituric acid colorimetry and Lowry method. Results: Picroside decreased the levels of alanine aminotransferase and aspartate aminotransferase in the serum resulting from acute-liver injured mice induced with D-GalN and LPS; it also reduced the content of MDA, and thus, enhanced the activity of SOD. Picroside 0 mg/kg was found to protect hepatocytes against apoptosis in a dose-dependent manner; it up-regulated the expression of bcl-2 genes, thus increased the bcl-2/bax ratio. Conclusion: Picroside 鈪an protect hepatocytes against injury and prevent hepatocytes from apoptosis. It might by upregulating the bcl-2 gene expression and antioxidation.

关键词： picroside Ⅱ hepatocytes apoptosis oxidative stress bcl-2 genes bax genes

SYNTHESIS AND BIOTECHNOLOGICAL APPLICATIONS OF VINYL POLYMERINORGANIC HYBRID AND MESOPOROUS MATERIALS

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Chinese Journal of Polymer Science 2000年第1期18卷 1-7页

作者： Yen Wei Kun-yuan Qiu Department of chemistry, Drexel university, Philadelphia, Pennsylvania 19104, usa Department of Polymer Science and Engineering, Peking university, Beijing 100871, China Drexel Univ Dept Chem Philadelphia PA 19104 USA Peking Univ Dept Polymer Sci & Engn Beijing 100871 Peoples R China

We describe the sol-gel synthesis of a new family of organic-inorganic hybrid materials, in which various vinyl polymers are covalently bonded to and uniformly distributed in inorganic oxide matrices. The materials can be tailored to have both good toughness and hardness while maintaining excellent optical transparency. Doping the sol-gel metal oxides with optically active compounds such as D-glucose results in new optical rotatory composite materials. Removal of the dopant compounds from the composites affords mesoporous oxide materials; which represents a new, nonsurfactant-templated route to mesoporous molecular sieves. We have successfully immobilized a series of enzymes and other bioactive agents in mesoporous materials. Catalytical activities of the enzyme encapsulated in mesoporous materials were found to be much higher than those encapsulated in microporous materials.

关键词： vinyl polymer-inorganic hybrid materials mesoporous materials sol-gel process biotech-nological applications

Liquid Chromatographic Resolution of Racemic 2-Phenyl-1,1-cyclopropanedicarbonitrile and its Analogues on Chiral Stationary Phase

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Chinese Chemical Letters 2000年第4期11卷 353-356页

作者： You Cheng LIU~(1,2) Xin Zhu LI~2 Jing LI~1 (1Department of chemistry. university of Science and Technology of China. Hefei 230026. 2 National Laboratory of Applied Organic chemistry and Department of chemistry Lanzhou university. Lanzhou 730000.) Univ Sci & Technol China Dept Chem Hefei 230026 Peoples R China Lanzhou Univ Dept Chem Lanzhou 730000 Peoples R China Lanzhou Univ Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China

Excellent resolution of racemic 2-phenyl-1,1-cyclopropanedicarbonitrile and its nine analogues was accomplished using 100-5CH1-TBB chiral stationary phase under normal-phase HPLC conditions. The influence of mobile ph... 详细信息

关键词： HPLC chiral stationary phase 2-phenyl-1,1-cyclopropanedicarbonitrile (PCN) chromatographic resolution

美国公立中小学校长评价制度的法律保障与效果分析

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教育发展研究 2010年第8期30卷 43-48页

作者：蔡奇杰弗吉尼亚大学教育学院

本文主要从法律角度探讨美国公立中小学校长评价制度,通过实例介绍了美国公立中小学校长评价制度的法律基础、评价指标和实施程序,以及美国州级校委会和下属的各学区如何履行相应的法律责任。在分析该制度实施效果的基础上,文章指出,法... 详细信息

本文主要从法律角度探讨美国公立中小学校长评价制度,通过实例介绍了美国公立中小学校长评价制度的法律基础、评价指标和实施程序,以及美国州级校委会和下属的各学区如何履行相应的法律责任。在分析该制度实施效果的基础上,文章指出,法律能够起到一定的规范、约束、指导和监督作用,但仍然无法充分保证校长评价的系统性和有效性。这一结论可以对我国校长评价制度的建设和发展提供些许启示。

关键词：美国公立中小学校长评价制度法律保障

Fluorescence turn-on chemosensor for Hg^(2+) based on a rhodamine derivative and its application in bioimaging

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Science China chemistry 2009年第6期52卷 760-764页

作者： LIU Chun1,2, ZHOU ZhiGuo2, GAO Yuan2, YANG Hong2, LI BaoGuo1, LI FuYou2 & HUANG ChunHui2 1 School of chemistry and Chemical Engineering, Inner Mongolia university, Hohhot 010021, China 2 Department of chemistry, Fudan university, Shanghai 200433, China School of chemistry and Chemical Engineering Inner Mongolia University Hohhot 010021 China Department of chemistry Fudan University Shanghai 200433 China

A fluorescence turn-on chemosensor based on rhodamine B derivative (FD10) has been developed as a highly sensitive chemosensor for Hg2+. A prominent fluorescence enhancement was measured in the presence of Hg2+, which was in agreement with the changes in the absorption spectrum. Furthermore, by means of laser scanning fluorescence microscopy experiments, it was demonstrated that FD10 was cell-permeable and could be used as a fluorescent probe for monitoring Hg2+ in living cells.

关键词： chemosensor fluorescence rhodamine bioimaging

Potential energy surfaces for low-lying electronic states of SO_2

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Science China chemistry 2006年第4期49卷 289-295页

作者： LI Anyang1, SUO Bing2, WEN Zhenyi2 & WANG Yubin2 1. Shanxi Key Laboratory of Physico-inorganic chemistry, Department of chemistry, Northwest university, Xi’an 710069, China 2. Institute of Modern Physics, Northwest university, Xi’an 710069, China 1. Shanxi Key Laboratory of Physico-inorganic chemistry Department of Chemistry Northwest University Xi’an 710069 China 2. Institute of Modern Physics Northwest University Xi’an 710069 China

The potential energy surfaces for the nine low-lying electronic states of SO2 have been constructed by using the multi-reference second order perturbation theory (MRPT2) with the basis set cc-pVTZ. The optimized geometries and the adiabatic excitation energies of these states are in good agreement with experiments and previous calculations. The crossings and avoided crossings dis- played in the potential energy surfaces are expounded.

关键词： cross of PES, MRPT2, SO2 (sulfur dioxide).