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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 450-454页

作者： wen yan Nan Li Bing-qiang Han The Key State Laboratory Breeding Base of Refractories and Ceramics Wuhan University of Science and Technology Wuhan 430081 China

Porous ceramics were prepared from kaolinite gangue and Al（OH）3 with double addition of MgCO3 and CaCO3 by the pore-forming in-situ *** characterizations of porous ceramics were investigated by X-ray diffractometry,scanning electron microscopy,and mercury porosimetry measurements,*** is found that although the decomposition of MgCO3 and CaCO3 has little contribution to the porosity,the double addition of MgCO3 and CaCO3 strongly affects the formation of liquid phase,and then changes the phase compositions,pore characterization,and *** appropriate mode is the sample containing 1.17wt% MgCO3 and 1.17wt% CaCO3,which has high apparent porosity（41.0%）,high crushing strength（53.5 MPa）,high mullite content（76wt%）,and small average pore size（3.24 μm）.

关键词： porous ceramics characterization kaolinite aluminum hydrxide additives

Syndiotactic Polymerization of Styrene and Copolymerization with Ethylene Catalyzed by Chiral Half-sandwich Rare-earth Metal Dialkyl Complexes

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Chinese Journal of Polymer Science 2018年第2期36卷 222-230页

作者： De-Qian Peng Xin-wen yan Shao-wen Zhang Xiao-Fang Li Key Laboratory of Cluster Science of Ministry of Education School of Chemistry and Chemical Engineering Beijing Institute of Technology

The syndiotactic polymerization of styrene（St） and the copolymerization of St with ethylene（E） were carried out by using a series of chiral half-sandwich rare-earth metal dialkyl complexes（Cp^x＊） as the catalysts. The complexes are Ln（CH2SiMe3）2（THF）（1-4： Ln = Sc（1）, Ln = Lu（2）, Ln = Y（3）, Ln = Dy（4）） bearing chiral cyclopentadienyl ligand containing bulky cylcohexane derivatives in the presence of activator and AliBu3. For the St polymerization, a high activity up to 3.1 × 10^6 g of polymer mol Ln^-1·h^-1 and a high syndiotactic selectivity more than 99% were achieved. The resulting syndiotactic polystyrenes（sPSs） have the molecular weights（Mn） ranging from 3700 g·mol^-1 to 6400 g·mol^-1 and the molecular weight distributions（Mw/Mn） from 1.40 to 5.03. As for the copolymerization of St and E, the activity was up to 2.4 × 10^6 g of copolymer mol Sc^-1·h^-1·MPa^-1, giving random St-E copolymers containing syndiotactic polystyrene sequences with different St content in the range of 15 mol%-58 mol%. These results demonstrate that the bulky cyclopentadienyl ligands of the chiral half-sandwich rare-earth metal complexes effectively inhibit the continued insertion of St monomers into the（co）polymer chain to some extent in comparison with the known half-sandwich rare-earth metal complexes.

关键词： Half-sandwich Rare-earth metal complex Syndiotacti cpolymerization Copolymerization Styrene Ethylene

Evolution of microstructure and texture of cold-drawn polycrystalline Ag with low stacking fault energy

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Science China(Technological Sciences) 2015年第7期58卷 1146-1153页

作者： MA XiaoGuang CHEN Jian CHEN Zheng yan wen State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University School of Materials Science and Chemical Engineering Xi'an Technological University

The evolution of microstructure and texture for drawn polycrystalline Ag was investigated by transmission electron microscopy and electron backscattering *** results show that there are deformation twins and some un-tangled discrete dislocations at low *** the strain is increased to 0.58,a lot of high density dislocation walls and microbands come into *** the same time,some twins lose the twinning relationship of 60°.At a strain of 0.94,both dislocation boundaries and twin boundaries will rotate to the axis direction of wires and the shear bands start to *** the strain is higher than 1.96,most of the boundaries are parallel to the drawn *** analysis indicates that with the strain increasing,the volume fraction of complex texture component decreases,butandtexture components ***,the variation in the volume fraction of each texture component as strains is not evident when the strains are higher than *** polycrystalline Ag with low stacking fault energy,complex texture components are easily formed.

关键词： polycrystalline Ag cold-drawn deformation microstructure deformation twinning stacking fault energy

Determination of reduced Young s modulus of thin films using indentation test

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Acta Metallurgica Sinica(English Letters) 2009年第6期22卷 468-480页

作者： Wuzhu yan Shifeng wen Jun LIU Zhufeng YUE Department of Engineering Mechanics Northwestern Polytechnical University Xi＇an 710129 China

The flat cylindrical indentation tests with different sizes of punch radius were investigated using finite element method （FEM） aimed to reveal the effect of punch size on the indentation behavior of the film/substrate system. Based on the FEM results analysis, two methods was proposed to separate film＇s reduced Young＇s modulus from a film/substrate system. The first method was based on a new weight function that quantifies film＇s and substrate＇s contributions to the overall mechanical properties of the film/substrate system in the flat cylindrical indentation test. The second method, a numerical approach, including fitting and extrapolation procedures was put forward. Both of the results from the two methods showed a reasonable agreement with the one input FE model. At last, the effect of maximum indentation depth and the surface micro-roughness of the thin film on the reduced Young＇s modulus of the film/substrate system were discussed. The methods proposed in the present study provide some new conceptions on evaluating other properties of thin films, e.g. creep, for which a flat-ended punch is also employed.

关键词： Indentation test Reduced Young's modulus Punch size effect Weight function Film/substrate system

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基于二次均值阴影集的FCM聚类算法

华北理工大学学报（自然科学版） 2025年第1期47卷 116-124页

作者：闫珊珊李文焱李丽红华北理工大学理学院河北唐山063210 河北省数据科学与应用重点实验室河北唐山063210 唐山市数据科学重点实验室河北唐山063210

为减少五区域阴影集中使用常数值来定义阴影集的五值隶属函数而造成的划归误差,利用平均值隶属度构建了一种基于二次均值阴影集的FCM聚类算法(FCM-5QSS)。首先,通过FCM算法得到对象与簇之间的隶属度矩阵;然后,使用平均值隶属度来定义阴... 详细信息

为减少五区域阴影集中使用常数值来定义阴影集的五值隶属函数而造成的划归误差,利用平均值隶属度构建了一种基于二次均值阴影集的FCM聚类算法(FCM-5QSS)。首先,通过FCM算法得到对象与簇之间的隶属度矩阵;然后,使用平均值隶属度来定义阴影集的五值隶属函数,同时通过模糊度性质及不确定性平衡原理得到两对阈值,进而将隶属度对应的对象划分到5个区域中;最后,通过划分核心区域和次核心区域中隶属度μ≥ηfalse的对象簇,得到聚类结果。在8个UCI公开数据集上的实验结果表明了所提出方法的有效性。

关键词：三支决策五区域阴影集平均值隶属度三支聚类

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A facile stereospecific synthesis of (Z)-2-sulfonyl-substituted 1,3-enynes via Sonogashira coupling of (E)-α-iodovinyl sulfones with 1-alkynes

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Chinese Chemical Letters 2007年第7期18卷 773-776页

作者： wen yan Hao Jian wen Jiang Ming Zhong Cai Department of Chemistry Jiangxi Normal University Nanchang 330022 China

（E）-α-Iodovinyl sulfones 1 underwent the Sonogashira coupling reactions with terminal alkynes 2 in piperidine at room temperature in the presence of 5 mol% of Pd（PPh3）4 and 10 mol% of CuI to stereospecifically af... 详细信息

关键词： (E)-α-Iodovinyl sulfone 1,3-Enynylsulfone Sonogashira coupling Terminal alkyne

Comparative study of different membranes as separators for rechargeable lithium-ion batteries

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 598-603页

作者： Hong-yan Guan Fang Lian yan Ren yan wen Xiao-rong Pan Jia-lin Sun School of Materials Science and Engineering University of Science and Technology Beijing

Membranes of polypropylene （PP）, PP coated with nano-A1203, PP electrospun with polyvinylidene fluoride- hexafluoropropylene （PVdF-HFP）, and trilayer laminates of polypropylene-polyethylene-polypropylene （PP/PE/PP） were comparatively studied. Their physical properties were characterized by means of thermal shrinkage test, liquid electrolyte uptake, and field emission scanning electron microscopy （FESEM）. Results show that, for the different membranes as PP, PP coated with nanowA1203, PP electrospun with PVdF-HFP, and PP/PE/PP, the thermal shrinkages are 14%, 6%, 12.6%, and 13.3%, while the liquid electrolyte uptakes are 110%, 150%, 217%, and 129%, respectively. In addition, the effects on the performance of lithium-ion batteries （LiFePO4 and LiNil/3Col/3Mn1/302 as the cathode material） were investigated by AC impedance and galvanostatic charge/discharge test. It is found that PP coated with A1203 and PP electrospun with PVdF-HFP can effectively increase the wettability between the cathode material and liquid electrolyte, and therefore reduce the charge transfer resistance, which improves the capacity retention and battery performance.

关键词： lithium-ion batteries membranes separators thermal stability electrochemical properties

Influence of reaction of Al2O3 and carbonaceous materials in Al2O3–C refractories on aluminum and carbon pick-up of iron

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Journal of Iron and Steel Research International 2020年第1期27卷 55-61页

作者： Yao-wu Wei yan-jun Dong Tao Zhang Jun-feng Chen wen yan The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Carbon-containing Al2O3 refractory crucibles and pure Al2O3 refractory crucible were fabricated to study the effect of carbon-containing Al2O3-C refractories on aluminum and carbon pick-up of *** crucibles with pure iron powder were placed in a vacuum induction furnace and heated at 1600℃ for regular time under flowing argon *** Al and C contents of iron samples were analyzed,and iron samples were also investigated using a field scanning electron microscope equipped with energy-dispersive *** results showed that carbon materials did affect the interac?tion of(Al2O3-C)/Fe system,carbothermal reduction in alumina occurred in the reaction system and the extent of reactions depended on the kinds of carbon materials.

关键词： Al2O3-C refractory Liquid iron Aluminum pick-up Carbon pick-up Carbothermal reduction

Numerically investigating the peculiar periphery of a supernova remnant in the medium with a density gradient:the case of RCW 103

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Research in Astronomy and Astrophysics 2021年第2期21卷 68-72页

作者： Chun-yan Lu Jing-wen yan Lu wen Jun Fang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China

The young shell-type supernova remnant RCW 103 has peculiar properties in the X-ray morphology obtained with *** southeastern shell is brighter in the X-rays,and the curved border of the shell in this region is flatter than the other *** investigate the formation of the peculiar periphery of the supernova remnant RCW 103 using 3D hydrodynamical *** that the supernova ejecta has been evolved in the medium with a density gradient,the detected shape of the periphery can be generally *** RCW 103,with the ejecta mass of 3.0 M,the density of the background material of 2.0 cm^(-3),and a gradient of 3.3-4.0 cm^(-3)pc^(-1),the X-ray periphery can be generally *** simulation turned out that the asymmetry of the SNR RCW 103 is mainly due to the inhomogeneous medium with a density gradient.

关键词： hydrodynamics(HD)-methods numerical-ISM-supernova remnants

Flexible CP-ABE Based Access Control on Encrypted Data for Mobile Users in Hybrid Cloud System

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Journal of Computer Science & Technology 2017年第5期32卷 974-990页

作者： wen-Min Li Xue-Lei Li Qiao-yan wen Shuo Zhang Hua Zhang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

In hybrid cloud computing, encrypted data access control can provide a fine-grained access method for organizations to enact policies closer to organizational policies. This paper presents an improved CP-ABE (ciphertext-policy attribute-based encryption) scheme to construct an encrypted data access control solution that is suitable for mobile users in hybrid cloud system. In our improvement, we split the original decryption keys into a control key, a secret key and a set of transformation keys. The private cloud managed by the organization administrator takes charge of updating the transformation keys using the control key. It helps to handle the situation of flexible access management and attribute alteration. Meanwhile, the mobile user's single secret key remains unchanged as well as the ciphertext even if the data user's attribute has been revoked. In addition, we modify the access control list through adding the attributes with corresponding control key and transformation keys so as to manage user privileges depending upon the system version. Finally, the analysis shows that our scheme is secure, flexible and efficient to be applied in mobile hybrid cloud computing.

关键词： attribute-based access control hybrid cloud outsourcing computing attribute alteration data verification