检索结果-南通市图书馆

Simulation of molecular dynamics of silver subcritical nuclei and crystal clusters during solidification

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第12期53卷 3203-3208页

作者： JIAN ZengYun1, CHEN Ji1, CHANG FangE1, ZENG Zhao1, HE Tan1 & JIE WanQi2 1 School of Materials science and Engineering, Xi’an Technological University, Xi’an 710032, china 2 State Key laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, china 1. School of Materials science and Engineering Xi’an Technological University Xi’an 710032 China2. State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi’an 710072 China

Molecular dynamics simulation is carried out to investigate the effects of cooling rate on the final configurations of silver after rapid solidification. The cooling rate for the formation of a silver amorphous phase is determined by analyzing its pair distribution function, H-A bond index, and the largest crystal cluster. Further, the equilibrium structures of the subcritical nuclei and crystal clusters are studied. The results show that the solidified microstructure is composed of a mixture of crystal clusters and amorphous phases at a certain cooling rate range. The size of the largest crystal cluster decreases with the increasing cooling rate, and it completely disappears when the cooling rate exceeds a critical value. The structures of the subcritical nuclei and the largest crystal cluster are composed of lamellar structures of fcc and hcp atoms, indicating that the lamellar structure of fcc and hcp atoms in the silver crystal originates from nucleation, and not from the growth of crystals.

关键词： molecular dynamics simulation amorphous phase subcritical nuclei crystal cluster cooling rate

MELTING CRYSTALLIZATION BEHAVIOR OF NYLON 66

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2001年第3期19卷 237-246页

作者： Qing-xin Zhang Zhi-shen Mo State Key laboratory of Polymer Physics & Chemistry Changchun Institute of Applied Chemistry Chinese Academy of sciences, Changchun 130022, china Chinese Acad Sci Changchun Inst Appl Chem State Key Lab Polymer Phys & Chem Changchun 130022 Peoples R China

Analysis of isothermal and nonisothermal crystallization kinetics of nylon 66 was carried out using differential scanning calorimetry (DSC). The commonly used Avrami equation and that modified by Jeziorny were used, respectively, to fit the primary stage of isothermal and nonisothermal crystallizations of nylon 66. In the isothermal crystallization process, mechanisms of spherulitic nucleation and growth were discussed. The lateral and folding surface free energies determined from the Lauritzen-Hoffman treatment are sigma = 9.77 erg/cm(2) and sigma (e) = 155.48 erg/cm(2), respectively; and the work of chain folding is q = 33.14 kJ/mol. The nonisothermal crystallization kinetics of nylon 66 was analyzed by using the Mo method combined with the Avrami and Ozawa equations. The average Avrami exponent (n) over bar was determined to be 3.45. The activation energies (DeltaE) were determined to be -485.45 kJ/mol and -331.27 kJ/mol, respectively, for the isothermal and nonisothermal crystallization processes by the Arrhenius and the Kissinger methods.

关键词： nylon 66 crystallization kinetics activation energy

在线全文

学校读者我要写书评

暂无评论

DNA微阵列图象信息的自动提取

计算机工程与应用 2004年第7期40卷 84-87页

作者：朱疆黄国亮高峻雄张旭于军华中科技大学电子科学与技术系武汉430074 生物芯片北京国家工程研究中心

微阵列图象分析是分子生物学中DNA微阵列杂交实验数据测定过程的一个重要部分。其目的是将微阵列图象中大量象素灰度信息简化为微阵列靶点的信号值。该文介绍了一种对DNA微阵列图象信息进行自动提取的方法,使用此方法完全不需要人为操作... 详细信息

微阵列图象分析是分子生物学中DNA微阵列杂交实验数据测定过程的一个重要部分。其目的是将微阵列图象中大量象素灰度信息简化为微阵列靶点的信号值。该文介绍了一种对DNA微阵列图象信息进行自动提取的方法,使用此方法完全不需要人为操作,可避免操作者主观性对实验的影响,提高数据提取的效率和可重复性。其关键步骤包括:图象滤波,图象灰度信息提取,微阵列间距确定,靶点定位和靶点信号值计算。实验结果表明使用此算法提取DNA微阵列图象信息具有重复性好、效率高和分析准确的特点。

关键词： DNA微阵列图象处理自动提取

在线全文

学校读者我要写书评

暂无评论

溶胶-凝胶VO_2薄膜转换特性研究

物理学报 2002年第4期51卷 852-856页

作者：袁宁一李金华林成鲁江苏石油化工学院信息科学系功能材料实验室常州213016 中国科学院上海冶金研究所信息功能材料国家重点实验室上海200050

利用溶胶凝胶法在SiO2 Si衬底上沉积高取向的V2 O5薄膜 ,在压强低于 2Pa ,温度高于 40 0℃的条件下 ,对V2 O5薄膜进行真空烘烤 ,获得了电阻率变化 3个数量级以上、弛豫宽度为 6 2℃的VO2 多晶薄膜 .以X射线衍射(XRD)、扫描电子显微... 详细信息

利用溶胶凝胶法在SiO2 Si衬底上沉积高取向的V2 O5薄膜 ,在压强低于 2Pa ,温度高于 40 0℃的条件下 ,对V2 O5薄膜进行真空烘烤 ,获得了电阻率变化 3个数量级以上、弛豫宽度为 6 2℃的VO2 多晶薄膜 .以X射线衍射(XRD)、扫描电子显微镜 (SEM)图和电阻率转换特性等实验结果为依据 ,详细分析了溶胶凝胶薄膜在真空烘烤时从V2 O5向VO2 的转化 ,它经历了从VnO2n +1 (n =2 ,3,4,6 )到VO2 的过程 .实验证明 ,根据选择合适的成膜热处理条件和真空烘烤条件是实现溶胶凝胶V2 O5结构向VO2

关键词：溶胶-凝胶法氧化钒薄膜 VO2膜转换特性

An Efficient Identity-Based Anonymous Signcryption Scheme

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural sciences 2008年第6期13卷 670-674页

作者： YU Yong LI Fagen XU Chunxiang SUN Ying School of Computer science and Engineering University of Electronic Science and Technology of China Chengdu 610054 Sichuan China

Signcryption is a cryptographic primitive that performs encryption and signature in a single logical step more efficiently than sign-then-encrypt approach. Till now, various kinds of signcryption schemes have been proposed. Among them, the requirement of signcrypter＇s privacy protection is needful in some practical applications. In this paper, a new identity-based anonymous signcryption scheme from hilinear pairings, which is the organic combination of identity-based ring signature and encryption scheme, is proposed. The proposed scheme is indistinguishable against the chosen ciphertext attack under the Decisional Bilinear Diffie-Hellman assumption in the random oracle model. Its unforgeability relies on the computational Diffieellman problem. Compared with the previous schemes, the new scheme is more efficient in computation.

关键词： identity-based ring signature anonynaous signcryption bilinear pairing

RESONANCE RADIATION OF SUBMERGED INFINITE CYLINDRICAL SHELL

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2002年第2期15卷 116-120页

作者： LiuTao Wan Lin Tang Weilin Fan JunState Key laboratory of Vibration, Shock & Noise, Shanghai Jiaotong University,Shanghai 200030, china *** State Key laboratory of Vibration Shock & Noise Shanghai Jiaotong University Shanghai 200030 China

The resonance sound radiation from submerged infinite elastic cylindricalshell, excited by internal harmonic line force, is investigated. The shell radiation power ispresented in terms of resonant modal radiation derived from resonance radiation theory (RRT). Theresonance radiation formulae are derived from classical Rayleigh normal mode solution, which areuseful for understanding the mechanism of sound radiation from submerged shells. As an example,numerical calculation of a thin steel cylindrical shell is done by using these two methods. It seemsthat the results of RRT solutions are in good agreement with that of Rayleigh normal modesolutions.

关键词： Cylindrical shell Sound and vibration Resonance radiation

Understanding the endocrine disruption of chiral pesticides:The enantioselectivity in estrogenic activity of synthetic pyrethroids

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2010年第5期53卷 1003-1009页

作者： WANG Cui 1,ZHANG Quan 1,ZHANG XiaoFeng 1,LIU Jing 2 & LIU WeiPing 2 1College of Biological and Environmental Engineering,Zhejiang University of technology,Hangzhou 310032,china 2Key laboratory of Environmental Remediation and Ecosystem Health,Ministry of Education College of Environmental and Resource sciences,Zhejiang University,Hangzhou 310029,china 1. College of Biological and Environmental Engineering Zhejiang University of Technology Hangzhou 310032 China2. Key Laboratory of Environmental Remediation and Ecosystem Health Ministry of Education College of Environmental and Resource Sciences Zhejiang University Hangzhou 310029 China

Synthetic pyrethroids(SPs) ,a family of chiral insecticides consisting of multiple stereoismers,have been regarded as estrogenic endocrine-disrupting chemicals(EDCs) .In this study,we applied the yeast two-hybrid and molecular docking(MD) assay to assess the enantioselective estrogenic activities of three commonly used SPs,bifenthrin(cis-BF) ,permethrin(PM) and fenvalerate(Fen) .The β-galactosidase analyses indicated that all of the testing pyrethroids displayed significant(p<0.05) *** results showed that the estrogenic potential of cis-BF was mainly attributed to *** PM nor Fen showed estrogenic ***,two stereoisomers of PM possessed estrogenic potential activities.αR-2R-Fen and αS-2S-Fen also induced the β-galactosidase *** inability to initiate the reporter gene expression by the racemic chemicals may be due to the low ratios of these isomers or the antagonism among *** strong hydrophobic interaction and the hydrogen bond between positive estrogenic isomers and ERα support our biological testing *** research demonstrated that the enantioselective estrogenic activity of chiral SPs was due to selective binding between their isomers and the ERα*** data suggests that enantioselectivity of these chiral pesticides is significant to their estrogenic activities.

关键词： enantioselectivity synthetic pyrethroids (SPs) endocrine disruption yeast molecular docking

INSTABILITY OF HEXAGONAL CRYSTALS IN LIPID MONOLAYERS

在线全文

学校读者我要写书评

暂无评论

南京大学学报(自然科学) 1996年第3期 530-531页

作者： Sun Cheng Wang Mu Jan Van Esch Ming Naiben Pier Bennema Helmut Ringsdrot R. J. M. Nolte(national laboratory of Solid State Microstructures, nanjing University, 210093, Nanjing, PRC& Center for Advanced Studies of science and technology of Microstructures

ＩＮＳＴＡＢＩＬＩＴＹＯＦＨＥＸＡＧＯＮＡＬＣＲＹＳＴＡＬＳＩＮＬＩＰＩＤＭＯＮＯＬＡＹＥＲＳ￥ＳｕｎＣｈｅｎｇ；ＷａｎｇＭｕ；ＪａｎＶａｎＥｓｃｈ；ＭｉｎｇＮａｉｂｅｎ；ＰｉｅｒＢｅｎｎｅｍａ；ＨｅｌｍｕｔＲｉｎｇ... 详细信息

ＩＮＳＴＡＢＩＬＩＴＹＯＦＨＥＸＡＧＯＮＡＬＣＲＹＳＴＡＬＳＩＮＬＩＰＩＤＭＯＮＯＬＡＹＥＲＳ￥ＳｕｎＣｈｅｎｇ；ＷａｎｇＭｕ；ＪａｎＶａｎＥｓｃｈ；ＭｉｎｇＮａｉｂｅｎ；ＰｉｅｒＢｅｎｎｅｍａ；ＨｅｌｍｕｔＲｉｎｇｓｄｒｏｔ；Ｒ．Ｊ．Ｍ．Ｎｏｌｔｅ...

关键词： instability two-dimensional crystal growth

Syndepositional Fault Controlling on Depositional Filling of the Third Member of Shahejie Formation in Beitang Sag

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth science 2009年第6期20卷 949-958页

作者：黄传炎王华肖敦清陈思王家豪廖远涛 Faculty of Earth Resources China University of Geosciences State Key laboratory of Geological Processes and Mineral Resources China University of Geosciences Key laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan Research Institute of Exploration and Development PetroChina Dagang Oilfield Company

In the continental lake basin whose structures were extraordinarily active, tectonism is an important factor in controlling the sequence and the depositional filling of the basin. This article reports the assemble patterns of syndepositional fault in the third member of Shahejie （沙河街） Formation in Beitang （北塘） sag. The results show that the comb-shape fracture system and the fracture transformation zone were developed in Beitang sag. These assemble patterns obviously controlled the sand-body and spatial distribution of sedimentary system. However, the steep slope belt of fault terrace, the multistage slope belt and the low uplift gentle slope belt controlled the development of sequence styles. Analyses of the spatial-temporal relationship of the assemble pattern of syndepositional faults and the sedimentary system help predict the favorable exploration zone.

关键词： Beitang sag syndepositional fault structural slope break zone the third member of Shahejie Formation.