检索结果-南通市图书馆

聚乙烯醇纤维掺量对高延性地聚合物混凝土早期抗裂和收缩性能影响

在线全文

学校读者我要写书评

暂无评论

大连理工大学学报 2024年第1期64卷 74-81页

作者：李杉周郑州卢亦焱王喆安俊澎武汉大学土木建筑工程学院湖北武汉430072

研究了聚乙烯醇(PVA)纤维掺量对高延性地聚合物混凝土早期塑性收缩开裂、干燥收缩和自生收缩的影响.结果表明,与地聚合物混凝土相比,掺PVA纤维的高延性地聚合物混凝土抗开裂性能和抗收缩性能显著提高,PVA纤维体积掺量为2%的地聚合物混... 详细信息

研究了聚乙烯醇(PVA)纤维掺量对高延性地聚合物混凝土早期塑性收缩开裂、干燥收缩和自生收缩的影响.结果表明,与地聚合物混凝土相比,掺PVA纤维的高延性地聚合物混凝土抗开裂性能和抗收缩性能显著提高,PVA纤维体积掺量为2%的地聚合物混凝土抗开裂和抗收缩性能最好.基于试验结果,建立了收缩预测模型,该模型能够一定程度反映地聚合物混凝土早期收缩特征.

关键词：地聚合物混凝土高延性塑性收缩开裂干燥收缩自生收缩收缩预测模型

Transport Properties of LCMO Granular Films Deposited by the Pulsed Electron Deposition Technique

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2011年第6期26卷 1027-1031页

作者：陈雷明 zhengzhou Institute of Aeronautical Industry Management

By finely controlling the deposition parameters in the pulsed electron deposition process, granular La 2/3 Ca 1/3 MnO 3 （LCMO） film was grown on silicon substrates. The substrate temperature, ambient pressure in the deposition chamber and acceleration potential for the electron beam were all found to affect the grain size of the film, resulting in different morphologies of the samples. Transport properties of the obtained granular films, especially the magnetoresistance （MR）, were studied. Prominent low-field MR was observed in all samples, indicating the forming of grain boundaries in the sample. The low-field MR show great sensitive to the morphology evolution, which reaches the highest value of about 4.% for the sample with the grain size of about 250 nm. More interestingly, positive-MR （p-MR） was also detected above 300 K when low magnetic field applying, whereas it disappeared with higher magnetic field applied up to 1.5 and 2 Tesla. Instead of the spin- polarized tunneling process being commonly regarded as a responsible reason, lattice mismatch between LCMO film and silicon substrate appears to be the origin of the p-MR

关键词： colossal magnetoresistance granular film transport properties

公益维权律师的职业性与制度化——以典型案例的“过程-事件”分析为视角

在线全文

学校读者我要写书评

暂无评论

江汉学术 2024年第4期43卷 58-65页

作者：张正州海南大学马克思主义学院海口570228

律师的职业化进程紧跟中国法制建设的步伐,在法律共同体理念的影响下不断展开,转型社会的公益维权实践逐渐催生出公益维权这一新兴律师群体。公益维权律师积极介入社会利益纷争,推动公益维权,实现个体权利诉求的满足或群体利益目标的达... 详细信息

律师的职业化进程紧跟中国法制建设的步伐,在法律共同体理念的影响下不断展开,转型社会的公益维权实践逐渐催生出公益维权这一新兴律师群体。公益维权律师积极介入社会利益纷争,推动公益维权,实现个体权利诉求的满足或群体利益目标的达成,进而指向政策优化乃至制度变革,具有显著的职业性。在公益维权实践中,通过将具体个案中的法律问题进行“外部化”操作,公益维权律师赋予具体个案以舆论影响力,将案件变成事件,在成功获得“维稳关注”之后,就应该再将事件变成案件、盘活制度资源,使公益维权个案“再法律化”,从而能够最终在制度化渠道之内得到妥善处理。把握公益维权事件过程中的行动策略,凸显公益维权实践的目标指向,扩展公益维权的制度变革效应,有利于增进公益维权律师的群体内聚与职业整合,最终实现公益维权这一新兴律师职业的制度化。

关键词：公益维权律师职业性 “过程-事件”分析制度化

A New C-glycosidic Hydrolysable Tannin from Rhodomyrtus tomentosa

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第1期8卷 39-40页

作者： Yan Ze LIU Ai Jun HOU Chun Ru JI Yang Jie WU(Department of Phytochemistry Henen College of Traditional Chinese Medicine Xhengzhou 450003.epartment of Oraganic Chemistry zhengzhou University zhengzhou 4.0052) Department of Phytochemistry Henan Coll. Traditional Chinese Med. Zhengzhou 450003 China Department of Organic Chemistry Zhengzhou University Zhengzhou 450052 China

Tomentosin(1), a new C-glycosidic hydrolysable tannin, isolated from the leaves of Rhodomyrtus tomentosa. Its structure determined by chemical method and (1)HNMR spectroscopic analysis.

关键词： A New C-glycosidic Hydrolysable Tannin from Rhodomyrtus tomentosa

SYNTHESIS AND CHARACTERIZATION OF ORGANOMONTMORILLONITE AND POLYAMIDE 66/MONTMORILLONITE NANOCOMPOSITES

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2002年第6期20卷 551-557页

作者： Cheng-shen Zhu Xin Kang Su-qin He Liu-yang Wang Li-yun Lu College of Materials Engineering,zhengzhou University, zhengzhou 4.0052, china College of Materials Engineering Zhengzhou University Zhengzhou 450052

The montmorillonites (MMTs), layered, smectite-type silicates, were premodified by two different methods prior to the polymer melt intercalation. In one case MMTs were modified with cetyltrimethylammonium bromide (CTAB), and termed as organomontmorillonites (OMMTs); in the other case MMTs were modified by nylon, and the products were called modified montmorillonites (MMMTs). The effects of CTAB and nylon on the MMTs were investigated by using TG and WAXD. The results show that interlayer spacings of CTAB and nylon modified MMTs are larger than that of sodium MMTs. Then, polyamide 66 (PA 66)/MMT nanocomposites were obtained through the method of melt intercalation of polymers. The nanocomposites were characterized by WAXD, TEM and Molau experiments. The results indicate that the MMTs disperse homogeneously in the PA 66 matrix. The mechanical properties of nanocomposites, such as tensile properties and flexural properties, were also measured and show a tendency to increase with increase of MMT content and reach the maximum values at 5phr MMT content. The heat distortion temperature (HDT) of the nanocomposites (7 phr) is about 32 K higher than that of pure PA 66.

关键词： montmorillonite polyamide 66 nanocomposites melt intercalation

Structure and magnetism of a porous three-dimensional metal-organic framework based on planar tetranuclear copper(Ⅱ) cluster units

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2010年第10期53卷 2118-2122页

作者： LI HuiJun, ZHANG ErPeng, GUO QianQian, HOU HongWei & FAN YaoTing Department of Chemistry, zhengzhou University, zhengzhou 4.0052, china Department of Chemistry Zhengzhou University Zhengzhou China

A porous three-dimensional copper(Ⅱ) metal-organic framework (MOF) {[Cu2(tci)(OH)(pip)0.5(H2O)]·6H2O}n (1) [tci = tris (2-carboxyethyl)isocyanurate, pip = piperazine] has been generated under hydrothermal conditions at 120 °C. Single crystal X-ray diffraction reveals that the polymer exhibits a novel three-dimensional framework based on planar tetranuclear copper(Ⅱ) cluster units. The variable temperature magnetic susceptibility data in the range 2-280 K show antiferromagnetic spin-spin coupling in the tetranuclear unit in complex 1. A theoretical fitting of the magnetic data gives J values of -31.3 cm-1, -30.8 cm-1, and 13.5 cm-1.

关键词： metal–organic framework tetranuclear copper cluster unit topology magnetism

A distributed hydrological model with its application to the Jinghe watershed in the Yellow River Basin

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2004年第z1期47卷 60-71页

作者： WANG Zhonggen1, ZHENG Hongxing1, LIU Changming1, , WU Xianfeng2 2 & ZHAO Weimin3 1. Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, china 2. Institute of Environmental Science, Beijing Normal University, Beijing 100875, china 3. Water Resources Conservation Committee of Yellow River, zhengzhou 450003. china Key Laboratory of Water Cycle & Related Land Surface Processes Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Institute of Environmental Science Beijing Normal University

For the purpose of water resources management in the Yellow River Basin with highly spatial difference, a daily distributed hydrological model was proposed, of which the determination of spatially-distributed parameters and model inputs processing were performed by means of GIS/RS. In the model, the computation of runoff yield was based on the topography index method and flow routing was modeled by Maskingum method. The operation of the model is followed by means of “command structure” technique based upon the topography of river network. A case study using the model was conducted for the Jinghe watershed, which locates at the middle Yellow River Basin. The simulation of the hydrological processes in 1996 has shown that water quantity balance errors were less than 5% and the Nash-Sutcliffe coefficient arrived at 0.7, indicating that the model structure is justifiable, and the precision of the model can satisfy the purpose of water resources management.

关键词： distributed hydrological model, structure and equation, GIS and RS, Jinghe Basin, Yellow River Basin.

A lumped mass nonconforming finite element method for nonlinear parabolic integro-differential equations on anisotropic meshes

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2009年第1期24卷 97-104页

作者： SHI Dong-yang WANG Hui-min LI Zhi-yan Dept. of Math., zhengzhou Univ., zhengzhou 4.0052, china Dept. of Math. Zhengzhou Univ. Zhengzhou China

A lumped mass approximation scheme of a low order Crouzeix-Raviart type noncon- forming triangular finite element is proposed to a kind of nonlinear parabolic integro-differential equations. The L2 error estimate is d... 详细信息

关键词： nonlinear parabolic integro-differential equation nonconforming finite element anisotropic mesh lumped mass error estimate

A Target Recognition Approach to Projecting HRR Profiles onto Subspace

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2003年第1期14卷 36-40页

作者： Pei Bingnan & Bao ZhengKey Lab. of Radar Signal Processing, Xidian University, Xi’an 710071, P. R. china Dept. of Electronic Engineering, zhengzhou University, zhengzhou 4.0052, P.R. china Key Lab. of adar Signal Processing Xidian University. Xi'an 710071 P. R. China Dept. of Electronic Engineering Zhengzhou University Zhengzhou 450052 P. R. China

Abstract: A array of the azimuthally averaged range-profile vectors and the inter-class and intra-class divergence matrixesare constructed iwth many frames of the high resolution range profiles which result from radar echoes of airplanes. Takingthe methods of whitening transformation and SVD produces a system of subspace vectors for target recognition. Where-upon, a template library for target recognition is built by the projection of a class-mean vector made from the radar dataonto the subspace for recognition. By Euclidean distance, a comparison is made between the above projection and eachtemplate in the library, to decide which class the target belongs to. Finally, simulations with the experimental radar dataarte given to show that the proposed method is robust to variation in azimuth and immune to additive Gaussian noisewhen SNR≥5dB.

关键词： Automatic target recognition High range resolution profile Distance classifier SVD Computer simulation