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Epoxidation of olefins with hydrogen peroxide catalyzed by a reusable lacunary-type phosphotungstate catalyst

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Science china chemistry 2011年第5期54卷 769-773页

作者： HUA Li,QIAO YunXiang,LI Huan,FENG Bo,PAN ZhenYan,YU YinYin,ZHU WenWen & HOU ZhenShan key laboratory for Advanced Materials Research Institute of Industrial Catalysis,East china university of Science and Technology,Shanghai 200237,china 1. key laboratory for Advanced Materials Research Institute of Industrial Catalysis East China University of Science and Technology Shanghai 200237 China

Olefins and allylic alcohols have been epoxidized with commercially available hydrogen peroxide (30% H2O2) using a phase transfer catalyst,composed of cetyltrimethylammonium cations and a lacunary-type phosphotungstate anion [PW11O39]7-or the complete Keggin-type heteropolyanion [PW12O40]3-,under two-phase conditions using ethyl acetate as the solvent. It was found that the lacunary-type catalyst showed higher activity and better recyclability than the complete Keggin-type catalyst under the same reaction conditions. 31P NMR spectroscopy and solubility measurements for the two catalysts revealed that the [PW11O39]7-anion had a much faster degradation rate than the [PW12O40]3-anion in an excess of H2O2,which resulted in the formation of more catalytically active species. As a result,the lacunary-type phosphotungstate anion-based catalyst gave a better catalytic performance than the complete Keggin-type anion in ethyl acetate.

关键词： heteropolyphosphotungstate lacunary epoxidation degradation rate

Structural Studies of [V_2S_6O_2(CuPPh_3)_4(CuMeCN)_2]·2CH_2Cl_2·2PrOH

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Chinese Journal of Structural chemistry 1996年第5期15卷 353-357页

作者： ZHANG Han-Hui YU Xiu-Fen YANG Rong-Sheng ZHENG Fa-Kun HUANG Liao-Yuan ZHUO Ru-Peng(Department of chemistry, Fuzhou university, Fuzhou, Fujian,350002)(state key laboratory of Structural chemistry, Fuzhou, Fujian, 350002) 福州大学化学系结构化学国家重点实验室福建福州

The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc=1. 57 g/cm3,μ= 19. 6 cm-1,F(000)=2160. Final R=0.074(Rw=0.082) for 2662 unique reflections with I≥3σ(I). The V atom in the compound retains the tetrahedral geometry of the VS3O with S-V-S or S-V-O angles of 108.6(6)～110.3 (6)°.The cluster core [V2Cu6S6O2] of the compound can be regarded as two cluster cores [VCu3S3O] bonded by bondings of the Cu-Cu'(distances of 2.774(3)～2.707(5) A) and Cu-S (distances of 2.463(7)～2.396(9) A) with centrosymmetric. Atoms of the cluster core V2Cu6 form a distorted cube with the Cu Cu'or the V-Cu distances of 2. 774(3)～2. 707(5) A.

关键词： crystal structure vanadium cluster copper cluster

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热应力对机翼结构固有频率的影响分析

振动．测试与诊断 2015年第6期35卷 1134-1139,1203-1204页

作者：贺旭东吴松张步云陈怀海南京航空航天大学机械结构力学及控制国家重点实验室南京210016

研究了热应力对飞行器机翼结构固有频率的影响。用ANSYS建立机翼结构有限元模型,计算了均匀温度场、非均匀温度场和非均匀可变温度场条件下的结构热应力分布和振动模态。根据固有振动的结构变形,分析了热应力对固有频率的影响效应。研... 详细信息

研究了热应力对飞行器机翼结构固有频率的影响。用ANSYS建立机翼结构有限元模型,计算了均匀温度场、非均匀温度场和非均匀可变温度场条件下的结构热应力分布和振动模态。根据固有振动的结构变形,分析了热应力对固有频率的影响效应。研究结果表明,热环境下机翼结构因材料属性的退化导致固有频率下降,但对于振型节线处于翼面内部的振动模态,附加热应力刚度矩阵在结构总刚度矩阵变化中起主导作用,使该阶固有频率增大。

关键词：高超声速热应力固有频率可变温度场

Fractal Characteristics of Coal Pores Based on Classic Geometry and Thermodynamics Models

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1150-1162页

作者： CAI Yidong~1,LIU Dameng~(1,*),YAO Yanbin~1,LI Junqian~1 and LIU Junlai~2 1 School of Energy Resources,china university of Geosciences,Beijing 100083,china 2 School of Earth Science and Resources,china university of Geosciences,Beijing 100083,china School of Energy Resources China University of Geosciences Beijing 100083 China School of Earth Science and Resources China University of Geosciences Beijing 100083 China *Correspondence: Dameng LIU *Correspondence: Corresponding author. E-mail: dmliu@***

To better understand the characteristics of coal pores and their influence on coal reservoirs, coal pores in eight main coalfields of North china were analyzed by mercury porosimetry and scanning electron microscopy（SEM）.Fractal characteristics of coal pores（size distribution and structure） were researched using two fractal models:classic geometry and *** two models establish the relationship between fractal dimensions and coal pores *** results include:（1） SEM imaging and fractal analysis show that coal reservoirs generally have very high heterogeneity;（2） coal pore structures have fractal characteristics and fractal dimensions characteristic of pore structures are controlled by the composition（e.g.,ash,moisture,volatile component） and pore parameters（e.g.,pore diameter,micro pores content） of coals;（3） the fractal dimensions（D;and D;） of coal pores have good correlations with the heterogeneity of coal pore *** fractal dimensions correlate to higher heterogeneity of pore *** fractal dimensions（D;and D;） have strong negative linear correlations with the sorted coefficient of coals （R;=0.719 and 0.639,respectively） that shows the heterogeneity of coal pores;（4） fractal dimension D;and petrologic permeability of coals have a strong negative exponential correlation（R;=0.82）.However, fractal dimension D;and petrologic permeability of coals have no obvious correlation;and（5） the model of classic geometry is more accurate for fractal characterization of coal pores in coal reservoirs than that of thermodynamics by optimization.

关键词： coal pores mercury porosimetry fractal dimensions thermodynamics model classic geometry model

Facile Synthesis of SnO_2 Hollow Microspheres and Their Optical Property

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Journal of Wuhan university of Technology(Materials Science) 2011年第2期26卷 302-305页

作者：贾铁昆 Department of Materials Science and Engineering Luoyang Institute of Science and Technology

SnO2 hollow microspheres were fabricated via a hydrothermal synthesis method assisting by the complex surfactant system of polyacrylamide and polyethylene *** by field emission scanning electron microscopy （FESEM） showed the SnO2 hollow spheres were composed of *** growth mechanism for the formation of hollow spheres was *** spectroscopy and photoluminescence （PL） were used to investigate the optical properties of the *** PL result showed that four peaks,containing the emission from recombination of free excitons,were observed in the photoluminescence spectrum.

关键词： SnO2 hollow spheres optical property

Developing land use scenario dynamics model by the integration of system dynamics model and cellular automata model

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Science china Earth Sciences 2005年第11期48卷 1979-1989页

作者： HE Chunyang, SHI Peijun, CHEN Jin, Li Xiaobing, PAN Yaozhong, LI Jing, LI Yuechen & LI Jinggang key laboratory of Environmental Change and Natural Disaster, Ministry of Education of china, Beijing Normal university College of Resources Science & Technology, Beijing Normal university, Beijing 100875, china 1. key laboratory of Environmental Change and Natural Disaster Ministry of Education of China Beijing Normal University China 2. College of Resources Science & Technology Beijing Normal University 100875 Beijing China

Modeling land use scenario changes and its potential impacts on the structure and function of the ecosystem in the typical regions are helpful to understanding the interactive mechanism between land use system and ecological system. A Land Use Scenario Dynamics (LUSD) model by the integration of System Dynamics (SD) model and Cellular Automata (CA) model is developed with land use scenario changes in northern china in the next 20 years simulated in this paper. The basic idea of LUSD model is to simulate the land use scenario de-mands by using SD model at first, then allocate the land use scenario patterns at the local scale with the considerations of land use suitability, inheritance ability and neighborhood effect by using CA model to satisfy the balance between land use scenario demands and supply. The application of LUSD model in northern china suggests that the model has the ability to reflect the complex behavior of land use system at different scales to some extent and is a useful tool for assessing the potential impacts of land use system on ecological system. In addition, the simulated results also indicate that obvious land use changes will take place in the farming-pastoral zone of northern china in the next 20 years with cultivated land and urban land being the most active land use types.

关键词： system dynamics, cellular automata, scenario, land use, model

Origin and controlling factors of chlorite coatings—an example from the reservoir of T_3x Group of the Baojie area,Sichuan Basin,china

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Petroleum Science 2009年第4期6卷 376-382页

作者： Peng Jun1,Liu Jinku2,Wang Yan2 and Liu Jianfeng2 1 Scientific Research Department,Southwest Petroleum university,Chengdu,Sichuan 610500,china 2 Graduate School,Southwest Petroleum university,Chengdu,Sichuan 610500,china Scientific Research Department Southwest Petroleum University Chengdu Sichuan China Graduate School Southwest Petroleum University Chengdu Sichuan China

The study of the chlorite coatings always attracts scholars in china and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone *** present,the study of the origin and the controlling factors is relatively *** occurrence,time of formation,genesis,controlling factors,and the mechanism of chlorite coatings inhibiting quartz overgrowths were studied in detail with thin section and SEM *** were from the sandstone reservoirs of the T3x Group in the Baojie area,the transitional zone from the middle to the south of Sichuan *** results indicate that the chlorite coatings on the walls of the pore spaces are oriented perpendicular to grain surfaces in the form of isopachous(even-thickness) grain-coating,while the chlorite coatings at the contacts between adjacent detrital grains are arranged with a preferred orientation tangential to the surface of detrital *** chlorite coatings were formed in the eogenetic *** were formed by recrystallization of Fe-rich clay films during the syndepositional period,and chlorite cements would be recrystallized after the coatings’ *** formation of chlorite coatings was mainly controlled by the depositional environment,provenance conditions,and diagenetic *** presence of chlorite coatings could result in the preservation of primary pores in deeply buried sandstone reservoirs by effectively inhibiting quartz overgrowths and the development of compaction and pressure solution.

关键词： Chlorite coatings occurrence time of formation origin controlling factor quartz overgrowths T3x Group

Characterization of GLUT4-containing vesicles in 3T3-L1 adipocytes by total internal reflection fluorescence microscopy

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Science china(Life Sciences) 2009年第7期52卷 665-671页

作者： WANG Yan1,2,ZHANG JinZhong1,2,CHEN Yu1,2,JIANG Li1,2,JI Wei1,2 & XU Tao1 1 National laboratory of Biomacromolecules,Institute of Biophysics,Chinese Academy of Sciences,Beijing 100101,china 2 Graduate university of Chinese Academy of Sciences,Beijing 100049,china 1. National laboratory of Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China 2. Graduate university of Chinese Academy of Sciences Beijing 100049 China

Insulin-responsive GLUT4(glucose transporter 4) translocation plays a major role in regulating glucose uptake in adipose tissue and *** or not there is a specialized secretory GSV(GLUT4 storage vesicle) pool,and more importantly how GSVs are translocated to the PM(plasma membrane) under insulin stimulation is still under *** the present study,we systematically analyzed the dynamics of a large number of single GLUT4-containing vesicles in 3T3-L1 adipocytes by TIRFM(total internal reflection fluorescence microscopy).We found that GLUT4-containing vesicles can be classified into three groups according to their mobility,namely vertical,stable,and lateral GLUT4-containing *** these groups,vertical GLUT4-containing vesicles exclude transferrin receptors and move towards the PM specifically in response to insulin stimulation,while stable and lateral GLUT4-containing vesicles contain transferrin receptors and show no insulin *** data demonstrate that vertical GLUT4-containing vesicles correspond to specialized secretory GSVs,which approach the PM directly and bypass the constitutive recycling pathway.

关键词： GLUT4 IRAP-pHluorin GSV transferring TIRFM

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核方法在人脸识别中的应用

计算机科学 2003年第5期30卷 82-84页

作者：朱美琳刘向东陈世福南京大学计算机软件新技术国家重点实验室南京大学银河软件开发中心南京210093

Kernel function is the function which computes dot product in feature spaces. Both the SVMs and kernelPCA are kernel-based learning methods. In this paper, the SVMs and kernel PCA are used to tackle the face recogni-tion problem. SVMs are classifiers which have demonstrated high generalization capabilities. Kernel PCA is a featureextraction technique which is proposed as a nonlinear extension of a PCA. We illustrate the potential of SVMs andkernel PCA on the Yale database and compare with a PCA based algorithm. The experiments indicate that SVMs andkernel PCA are superior to the PCA method.

关键词：人脸识别核方法模式识别人脸图像几何特征模板匹配图像识别图像处理