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Rare Metals 2012年第5期31卷 470-473页

作者： SUN wei ZHU Minggang FANG Yikun PAN wei li Jiajie li Yanfeng li wei Division of functional Materials Central Iron and Steel Research Institute Group Beijing 100081 China

The microstructures and magnetic properties of Ce-32.15Co_49.36Cu_9.84Fe_9.65 magnet sintered at the temperatures ranging from 1005 to 1105 °C were investigated. The results on scanning electron microscopy and X-ray diffraction analysis indicate that the remanence B r of the magnets is mainly influenced by the degree of the easy-axis orientation when sintering temperature is less than 1085 °C, the rapidly increasing amount of the secondly phase (5:19 phase) gives rise to the deterioration of the magnetic properties of the magnet above 1085 °C. Moreover, it is found that intrinsic coercivity H ci is strongly related to the content of copper in the matrix of the sintered magnets. The optimal sintering temperature is located in 1025~1055 °C, the corresponding magnetic properties of the magnets are B_r =0.685T, H_(ci) =350kA·m^-1 , and maximum energy product (BH)_m =85.6 kJ·m 3 .

关键词： Ce-Co permanent magnet sintering temperature coercivity

The Optimal Preconditioner of Strictly Diagonally Dominant Z-matrix

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 305-312页

作者： Ji-cheng li wei li Department of Mathematics Xi'an Jiaotong University Xi'an 710049 China

In this paper, we present a series of new preconditioners with parameters of strictly diagonally dominant Z-matrix, which contain properly two kinds of known preconditioners as special cases. Moreover, we prove the monotonicity of spectral radiuses of iterative matrices with respect to the parameters and some comparison theorems. The results obtained show that the bigger the parameter k is（i.e., we select the more upper right diagonal elements to be the preconditioner）, the less the spectral radius of iterative matrix is. A numerical example generated randomly is provided to illustrate the theoretical results.

关键词： Preconditioned method iteration splitting linear system

Study on Assessment of Mine Environments

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Acta Geologica Sinica(English Edition) 2008年第5期82卷 1027-1034页

作者： WU Qiang li wei li Ruijun China University of Mining and Technology Beijing 100083 China

Mine environmental evaluation is the key to mine environmental study. On the basis of the characteristics of the mine environmental problems, they are classified into （1） three wastes problem, （2） ground distortion, （3） contradiction among mine drainage, water supply, ecological environment, （4） desertification, and （5） soil erosion. The evaluation is the basis of mine environmental problem classification and investigation, mine environmental rehabilitation, and the information system constructed can be used for subsequent research of evaluation techniques. A synthetic assessment of the 5 kinds of mine environmental problems can be divided into single-factor or multi-factor synthetic assessments; while by the viewpoint of time, the mine environmental assessment can be classified as the historical assessment, the current status assessment and the forecasting assessment.

关键词： single-factor assessment multi-factor synthetic assessment historical assessment current status assessment

Magnetic microstructure and coercivity mechanism of high performance Nd-Fe-B magnets

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Rare Metals 2006年第Z1期25卷 630-632页

作者： ZHU Minggang liU Xingmin FANG Yikun li Zhengbang li wei Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China Central Iron & Steel Research Institute Beijing 100081 China

Magnetic microstructure of high performance Nd-Fe-B magnets was investigated by using magnetic force microscopy. The correlation between magnetic microstructure and coercivity for high performance Nd-Fe-B magnets was studied. It is found that the magnets with different coercivity mechanism take on different microstructures and magnetism. Moreover, the magnetic microstructures of high performance permanent magnets can be explained by the starting field theory model.

关键词： Nd-Fe-B permanent magnets magnetic domains reversal of magnetism starting field theory

Imazaquin degradation and metabolism in a sandy loam soil amended with farm litters

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Journal of Environmental Sciences 2007年第9期19卷 1108-1113页

作者： WANG Hui-li li Yan-yan wei Guo-hui WANG Xue-dong Key Laboratory of Pesticide and Chemical Biology of Ministry of Education Central China Normal University Wuhan 430079 China

Irnazaquin applied in legume crops has a long residual time in soil, which often impacts safety of the susceptible crops. To increase safety of imazaquin application, two composted litters, bovine manure （BM） and chicken manure （CM）, were used to determine their effects on imazaquin environmental behavior by incorporating each kind of manure into the tested sandy loam soil at 10% （w/w）. The degradation of imazaquin in BM- and CM-amended soil was about 2.4 and 1.5 times, respectively, faster than that in unamended soil. The half-lives of imazaquin in BM-amended soil varied between 6.7 and 15.4 d over the temperature range of 20 to 40℃, and the degradation rate constant （k） increased by a factor of about 1.5 for every 10℃ change. Higher mix ratio did not significantly increase the degradation, and the optimal active degradation of imazaquin was observed approximately at the mix ratio of 10：1 of soil to BM. The different moisture levels had negligible effect on imazaquin degradation. In both unamended and BM-amended treatments, two metabolites were observed at 5, 10 and 30 d after treatment. One metabolite at retention time （RT） of 8.4 rain was identified as 2-（4- hydroxyl-5-oxo-2-imidazolin-2-yl） quinoline acid, originating from the loss of isopropyl group and hydroxylation at the 4-position of imidazolinone ring. The other at RT of 12.9 rain was identified as quinoline-2,3-dicarboxylic anhydride, resulting from detachment of imidazolinone ring and the forming of dicarboxylic anhydride. This finding suggested that the addition of farm litters into soil might be a good management option since it can not only increase soil fertility but also contribute to increase safety of imazaquin application to the following susceptible crops.

关键词： imazaquin farm litter enhanced degradation metabolite

Bovine Serum Albumin Loaded Solid lipid Nanoparticles Prepared by Double Emulsion Method

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Chemical Research in Chinese Universities 2010年第1期26卷 136-141页

作者： li Zhen li Xin-wei ZHENG li-qiang liN Xiao-hong GENG Fei YU li Key Laboratory of Colloid and Interface Chemistry Ministry of Education Shandong University Jinan 250100 P. R. China

Solid lipid nanoparticles loaded with bovine serum albumin（BSA） were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. The physical stability of the nanoparticles was investigated by zeta potential measurement and they were shown to be quite stable. Fluorescence spectroscopy confirmed that the loaded position of BSA was on the interface between the inner aqueous phase and the solid lipid phase. Both Fourier-transform infrared spectroscopy and circular dichroism spectra indicate that BSA in the nanoparticles was not destroyed, but the secondary structure was disrupted slightly.

关键词： Solid lipid nanoparticle Double emulsion Bovine serum albumin Drug model

Alphastatin downregulates vascular endothelial cells sphingosine kinase activity and suppresses tumor growth in nude mice bearing human gastric cancer xenografts

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World Journal of Gastroenterology 2006年第26期12卷 4130-4136页

作者： lin Chen Tao li Rong li Bo wei Zheng Peng Department of General Surgery General Hospital of Chinese PLA Beijing 100853 China

AIM： To investigate whether alphastatin could inhibit human gastric cancer growth and furthermore whether sphingosine kinase （SPK） activity is involved in this process. METHODS： Using migration assay, MTT assay and Matrigel assay, the effect of alphastatin on vascular endothelial cells （ECs） was evaluated in vitro. SPK and endothelial differentiation gene （EDG）-1, -3, -5 mRNAs were detected by reverse transcription-polymerase chain reaction （RT-PCR）. SPK activity assay was used to evaluate the effect of alphastatin on ECs. Matrigel plug assay in nude mice was used to investigate the effect of alphastatin on angiogenesis in vivo. Female nude mice were subcutaneously implanted with human gastric cancer cells （BGC823） for the tumor xenografts studies. Micro vessel density was analyzed in Factor Ⅷ-stained tumor sections by the immunohistochemical SP method. RESULTS： In vitro, alphastatin inhibited the migration and tube formation of ECs, but had no effect on proliferation of ECs. RT-PCR analysis demonstrated that ECs expressed SPK and EDG-1, -3, -5 mRNAs. In vivo, alphastatin sufficiently suppressed neovascularization of the tumor in the nude mice. Daily administration of alphastatin produced significant tumor growth suppression. Immunohistochemical studies of tumor tissues revealed decreased micro vessel density in alphastatin-treated animals as compared with controls. CONCLUSION： Downregulating ECs SPK activity may be one of the mechanisms that alphastatin inhibits gastric cancer angiogenesis. Alphastatin might be a useful and relatively nontoxic adjuvant therapy in the treatment of gastric cancer.

关键词： Stomach neoplasm Angiogenesis Endothelial cells Sphingosine kinase Cancer therapy

Syntheses, Structures, and Properties of Five Coordination Polymers Involving Phthalic Acid

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Chemical Research in Chinese Universities 2011年第5期27卷 724-729页

作者： WU li-li HE Rong wei Zhen SONG Hui-hua College of Chemistry and Material Sciences Hebei Normal University Shijiazhuang 050016 t~ R. China

Five new coordination polymers Cu（phen）（H2O）（phth）·CH3OH（1）, [Cu（2,2′-bipy）（H2O）]（phth）·3.5H2O（2）, Zn（phen）（phth）（H2O）·1.125H2O（3） and [M（4,4′-bipy）（H2O）2]（phth）·2H2O[M=Zn（4）, Mn（5）]（H2phth=phthalic acid, bipy=bipyridine, phen=1,10-phenanthroline） have been synthesized from the amino acid derivatives（phthalyl-l- valine, H2L） and structurally characterized. H2L was hydrolyzed into phth2- group during the reaction, but the strucure feature was different from that of the complex directly synthesized from H2phth in the reported literature, revealing that H2L played an important role in composing the novel compounds. Compounds 1, 2 and 3 are all 1D chains, but the differences are that compound 1 is further hydrogen-bonded into 2D networks, and compound 2 is further extended into 3D supramolecular network through π-π stacking and hydrogen-bonding interactions. However, compound 3 is a 1D helix chain structure and further links into 2D networks through π-π stacking. Compounds 4 and 5 are isostructural and exhibit the same 2D layers, which are further connected by hydrogen-bonding interactions to form 3D supramolecular network. Antiferromagnetic superexchange was observed for compounds 1, 2 and 5.

关键词： Crystal structure Amino acid derivative Phthalic acid Coordination polymer

An efficient synthesis of 3-(guaiazulene-1-yl)succinimides by addition of guaiazulene to maleimides

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Chinese Chemical Letters 2011年第7期22卷 789-792页

作者： Dao lin Wang Shao Fei li wei li Yuan Feng li li Nan lin Key Laboratory of Synthesis & Application of Functional Compound College of Chemistry & Chemical Engineering Bohai University Jinzhou 121001 China

A facile, efficient synthesis of 3-（guaiazulen-l-yl）succinimides was developed by Michael-type addition of guaiazulene to maleimides in the presence of p-toluenesulfonic acid under mild reaction conditions.

关键词： Guaiazulene Succinimidcs Michael-type addition p-Toluenesulfonic acid

Rapid Detection of rpoB Gene Mutations in Rif-resistant *** Isolates by Oligonucleotide Microarray

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Biomedical and Environmental Sciences 2009年第3期22卷 253-258页

作者： AI-HUA SUN XING-li FAN li-wei li li-FANG WANG WEN-YING AN JIE YAN Department of Basic Medicine Zhejiang Medical College Hangzhou 310053 Zhejiang China Department of Medical Microbiology and Parasitology Zhejiang University Hangzhou 310058 Zhejiang China School of lnternational Stud3 Zhejiang University Hangzhou 310058 Zhejiang China

Objective To detect the specific mutations in rpoB gene of Mycobacterium tuberculosis by oligonucleotide microarray. Methods Four wild-type and 8 mutant probes were used to detect rifampin resistant strains. Target DNA of M. tuberculosis was amplified by PCR, hybridized and scanned. Direct sequencing was performed to verify the results of oligonucleotide microarray Results Of the 102 rifampin-resistant strains 98 （96.1%） had mutations in the rpoB genes. Conclusion Oligonucleotide microarray with mutation-specific probes is a reliable and useful tool for the rapid and accurate diagnosis of rifampin resistance in M. tuberculosis isolates.

关键词： Mycobacterium tuberculosis Rifampin resistance rpoB gene / site mutation Oligonucleotide microarray/detection