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镉Ⅱ-meso(4-磺基苯)卟啉络合物的极谱伏安行为 被引量:7
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作者 王小萍 张勇 潘景浩 《分析化学》 SCIE EI CAS CSCD 北大核心 2001年第3期290-292,共3页
用紫外分光光度法和循环伏安法考察了镉与meso(4 磺基苯 )卟啉在强碱性溶液中形成的络合物的特性。结果表明 ,加入Cd 后该卟啉的索瑞特 (Soret)吸收带发生发红移 ,循环伏安图上出现了新的还原峰 ,峰电位为 - 1.2 0V(vs .SCE) ,络合物... 用紫外分光光度法和循环伏安法考察了镉与meso(4 磺基苯 )卟啉在强碱性溶液中形成的络合物的特性。结果表明 ,加入Cd 后该卟啉的索瑞特 (Soret)吸收带发生发红移 ,循环伏安图上出现了新的还原峰 ,峰电位为 - 1.2 0V(vs .SCE) ,络合物的络合比为 1∶1,稳定常数 β =1.19× 10 7。本文还用多种电化学技术证明了络合物的还原峰电流具有吸附特征 ;用示波极谱法二阶导数波测试了峰电流与镉离子浓度的关系 ,结果表明镉离子在 3× 10 -7~ 1× 10 -5mol/L的浓度范围内与络合物峰电流有良好的线性关系 ;并求得了电极反应的电子转移数为 2。此外本文还对络合物的电极反应机理进行了探讨。 展开更多
关键词 极谱伏安行为 meso(4-磺基苯)卟啉 镉(Ⅱ)络合物 电极反应机理
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meso,β-和β,β-全氟醚基磺酸酯桥连双卟啉的合成 被引量:2
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作者 曾卓 金利美 +1 位作者 郭灿城 陈庆云 《化学学报》 SCIE CAS CSCD 北大核心 2004年第3期288-294,共7页
β 氟砜基全氟醚基取代四芳基卟啉与 5 (4 羟苯基 ) 10 ,15 ,2 0 三苯基卟啉、BINOL反应分别生成meso ,β 和 β ,β 全氟醚基磺酸酯桥连双卟啉 ,双卟啉与醋酸锌在CHCl3 /CH3 OH中回流可高产率获得双锌卟啉 ,测定并讨论了meso ,β ... β 氟砜基全氟醚基取代四芳基卟啉与 5 (4 羟苯基 ) 10 ,15 ,2 0 三苯基卟啉、BINOL反应分别生成meso ,β 和 β ,β 全氟醚基磺酸酯桥连双卟啉 ,双卟啉与醋酸锌在CHCl3 /CH3 OH中回流可高产率获得双锌卟啉 ,测定并讨论了meso ,β 和 β ,β 展开更多
关键词 meso β-双卟啉 β β-双卟啉 桥连卟啉 合成 β-氟砜基全氟醚基取代四芳基卟啉 紫外可见光谱 荧光光谱
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关于meso紧和次meso紧的σ-积
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作者 黄蕴魁 《西南师范大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第2期138-141,共4页
主要获得了如下结果 :设X =σ{Xα:α∈A} ,如果X的每个有限子积是meso紧 (次meso紧 )的且X正规 ,则X是meso紧 (次meso紧 )
关键词 Σ- meso meso
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关于σ-序列Meso紧空间的Tychonoff乘积性质 被引量:1
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作者 李泽君 《四川师范大学学报(自然科学版)》 CAS CSCD 2000年第2期117-121,共5页
主要在σ 序列Meso紧空间上获得两个结论 :(1)若{Xi:i∈N}是可数个σ 序列Meso紧的强 空间 ,则 i∈NXi 是σ 序列Meso紧的强 空间 ;(2 )若X是P 空间 ,Y是强 空间 ,X ,Y都是σ 序列Meso紧空间 ,则X×Y是σ
关键词 σ-序列meso 强Σ-空间 拓扑空间 T乘积性质
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Powell dynamic identification of displacement parameters of indeterminate thin-walled curve box based on FCSE theory 被引量:5
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作者 Jian Zhang Chu-Wei Zhou Jia-Shou Zhuo 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第3期452-460,共9页
The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistic... The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory,dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples,it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence,which demonstrates that the presented method and the compiled procedure are correct and reliable.During parameters鈥?iterative processes,the Powell theory is irrelevant with the calculation of finite curve strip element(FCSE) partial differentiation,which proves high computation effciency of the studied method. 展开更多
关键词 Powell theory - Indeterminate curve box . Displacement parameters - Fibonacci search method.Flexibility theory
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Interaction of Photoactive[Fe(CN)_6]^(4-) with TiO_2 Anatase(101) Surface:A Periodic Density Functional Theory Study 被引量:2
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作者 XU Ying CHEN Wen-Kai CAO Mei-Juan LIU Shu-Hong LI Jun-Qian 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第3期361-366,共6页
The plane-wave pseudopotential function method, based on density-functional theory, has been used to calculate the adsorption, electronic band structures, orbitals and optical absorption spectrum of [Fe(CN)6]^4- on ... The plane-wave pseudopotential function method, based on density-functional theory, has been used to calculate the adsorption, electronic band structures, orbitals and optical absorption spectrum of [Fe(CN)6]^4- on TiOz anatase(101) surface. Our calculations reveal that the surface-modified anatase system has large adsorption energy and a much narrower band gap. [Fe(CN)6]^4- adsorption on the (101) surface could lead to a large red shift of the anatase optical absorption threshold, which extends into a visible region significantly. The calculated results are in agreement with the experiment and other theoretical studies reasonably. It is very important for the understanding and further development ofphotovoltaic materials that are active under visible light. 展开更多
关键词 density functional theory (DFT) [Fe(CN)6]^4- anatase(101) surface adsorption absorption
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Cosmological parameters for spatially flat dust filled Universe in Brans-Dicke theory
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作者 Gopi Kant Goswami 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第3期55-66,共12页
We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distan... We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distance and apparent magnitude have been obtained for our model. The theoretical results are compared with observed values of the latest 287 high redshift (0.3 ≤ z ≤1.4) Type Ia supernova data taken from the Union 2.1 compilation to estimate present values of matter and dark energy parame- ters, (Ωm)0 and (ΩA)0. We have also estimated the present value of Hubble's constant H0 in light of an updated sample of Hubble parameter measurements including 19 independent data points. The results are found to be in good agreement with recent astrophysical observations. We also calculated various physical parameters such as matter and dark energy densities, present age of the Universe and decelera- tion parameter. The value for Brans-Dicke-coupling constant ω is set to be 40 000 based on accuracy of solar system tests and recent experimental evidence. 展开更多
关键词 COSMOLOGY osmological parameters - cosmology observations- dark energy-Brans-Dicke theory
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Comparative Studies of 1,4-Bis[2-(4-Pyridyl)ethenyl]-benzene Using Density Functional Theory
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作者 CHENG Jian-bo Lǚ Jia-ping GONG Bao-an LI Wen-zuo 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第4期469-473,共5页
The optimized molecular structure and harmonic vibrational frequencies of a 1,4-bis [ 2-(4-pyridyl)ethenyl]- benzene(BPENB) molecule were calculated via five popular density functional theory(DFI') methods. On ... The optimized molecular structure and harmonic vibrational frequencies of a 1,4-bis [ 2-(4-pyridyl)ethenyl]- benzene(BPENB) molecule were calculated via five popular density functional theory(DFI') methods. On the basis of the comparison between calculated and experimental results, it is concluded that the B3PW91 and B3LYP methods are superior to the others in optimizing structures, and the BPW91 method reproduces the observed fundamental fre-quencies most satisfactorily. 展开更多
关键词 1 4-Bis[2-(4-pyridyl)ethenyl]-benzene Density functional theory Vibrational frequencies BPW91
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2024-T3铝合金拉伸及剪切断裂行为 被引量:7
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作者 姜薇 李亚智 +1 位作者 苏杰 束一秀 《固体火箭技术》 EI CAS CSCD 北大核心 2015年第3期426-432,450,共8页
2024铝合金材料在拉伸和扭转载荷作用下表现出截然不同的失效机理。结合试验和数值方法,研究了应力状态对2024-T3铝合金韧性断裂行为的影响规律。首先,对圆棒和薄壁圆筒试验件分别进行了拉伸和扭转试验,从断面形貌以及断裂应变与应力状... 2024铝合金材料在拉伸和扭转载荷作用下表现出截然不同的失效机理。结合试验和数值方法,研究了应力状态对2024-T3铝合金韧性断裂行为的影响规律。首先,对圆棒和薄壁圆筒试验件分别进行了拉伸和扭转试验,从断面形貌以及断裂应变与应力状态间关系两个方面,考察了应力状态对2024-T3铝合金断裂机理的影响规律。然后,基于Gurson理论在商业有限元软件ABAQUS中开发了同时适用于拉伸和剪切断裂模式的细观损伤本构,对2024-T3铝合金的弹塑性响应和裂纹扩展路径进行了数值分析。与试验结果对比研究表明,本文发展的细观损伤本构能够较好预测延性金属材料在多种应力状态下的损伤破坏过程。 展开更多
关键词 延性断裂 拉伸失效 剪切失效 细观损伤模型 Gurson理论
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Meso紧空间的无限Tychonoff乘积性质 被引量:1
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作者 刘华军 许召春 《贵阳学院学报(自然科学版)》 2007年第4期1-3,共3页
主要证明了如下结果:(1)如果X=∏α∈ΛXα是|Λ|-仿紧空间,则X是meso紧的当且仅当F∈[Λ]<ω,∏α∈FXα是meso紧的;(2)如果X=∏i∈ωXi是可数仿紧的,则下列三条件等价:X是meso紧的;F∈[Λ]<ω,∏α∈FXα是meso紧的;n∈ω... 主要证明了如下结果:(1)如果X=∏α∈ΛXα是|Λ|-仿紧空间,则X是meso紧的当且仅当F∈[Λ]<ω,∏α∈FXα是meso紧的;(2)如果X=∏i∈ωXi是可数仿紧的,则下列三条件等价:X是meso紧的;F∈[Λ]<ω,∏α∈FXα是meso紧的;n∈ω,∏i≤n Xi是meso紧的。 展开更多
关键词 meso |↑∧ |-仿紧空间 可数仿紧
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环的相对于余遗传Torsion Theory的Jacobson根
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作者 赵文正 《河南师范大学学报(自然科学版)》 CAS CSCD 1996年第4期5-8,共4页
本文推广了环论中拟正则左理想的概念,引入τ-拟正则左理想的概念,给出环的相对于余遗传Torsiontheory的Jacobson根的元素刻划.
关键词 τ-小子模 τ-拟正则左理想 余遗传 Torsion theory
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Aviation Accident Causation Analysis Based on Complex Network Theory 被引量:11
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作者 YUE Rentian LI Junwei HAN Meng 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第4期646-655,共10页
Accident causation analysis is of great importance for accident prevention.In order to improve the aviation safety,a new analysis method of aviation accident causation based on complex network theory is proposed in th... Accident causation analysis is of great importance for accident prevention.In order to improve the aviation safety,a new analysis method of aviation accident causation based on complex network theory is proposed in this paper.Through selecting 257 accident investigation reports,45 causative factors and nine accident types are obtained by the three-level coding process of the grounded theory,and the interaction of these factors is analyzed based on the“2-4”model.Accordingly,the aviation accident causation network is constructed based on complex network theory which has scale-free characteristics and small-world properties,the characteristics of causative factors are analyzed by the topology of the network,and the key causative factors of the accidents are identified by the technique for order of preference by similarity to ideal solution(TOPSIS)method.The comparison results show that the method proposed in this paper has the advantages of independent of expert experience,quantitative analysis of accident causative factors and statistical analysis of a lot of accident data,and it has better applicability and advancement. 展开更多
关键词 aviation safety accident causation complex network theory grounded theory “2-4”model
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Relationships between Relative Spectral Lags and Relative Widths of Gamma-ray Bursts 被引量:3
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作者 Zhao-Yang Peng Rui-Jing Lu +1 位作者 Yi-Ping Qin Bin-Bin Zhang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第3期428-434,共7页
The phenomenon of gamma-ray burst (GRB) spectral lags is very common, but a definitive explanation has not yet been given. From a sample of 82 GRB pulses we find that the spectral lags are correlated with the pulse ... The phenomenon of gamma-ray burst (GRB) spectral lags is very common, but a definitive explanation has not yet been given. From a sample of 82 GRB pulses we find that the spectral lags are correlated with the pulse widths, however, there is no correlation between the relative spectral lags and the relative pulse widths. We suspect that the correlations between spectral lags and pulse widths might be caused by the Lorentz factor of the GRBs concerned. Our analysis on the relative quantities suggests that the intrinsic spectral lag might reflect other aspect of pulses than the aspect associated with the dynamical time of shocks or that associated with the time delay due to the curvature effect. 展开更多
关键词 GAMMA-RAYS bursts - methods statistical - gamma-rays theory
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First-principles Study on Geometric and Electronic Structures of Si(111)-√7× √3-In Surface Reconstruction
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作者 商波 袁岚峰 杨金龙 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第4期403-408,I0003,共7页
In order to determine the structures of Si(111)-√7 √3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calcula... In order to determine the structures of Si(111)-√7 √3-In surfaces and to understand their electronic properties, we construct six models of both hexagonal and rectangular types and perform first-principles calculations. Their scanning tunneling microscopic images and work functions are simulated and compared with experimental results. In this way, the hex-H3' and rect-T1 models are identified as the experimental configurations for the hexagonal and rectangular types, respectively. The structural evolution mechanism of the In/Si(lll) surface with indium coverage around 1.0 monolayer is discussed. The 4×1 and -√7× √3 phases are suggested to have two different types of evolution mechanisms, consistent with experimental results. 展开更多
关键词 Surface reconstruction Si(111)-√7× √3In Density functional theory Scanning tunnueling microscopic image
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A unified analysis of a micro-beam,droplet and CNT ring adhered on a substrate:Calculation of variation with movable boundaries 被引量:3
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作者 Jian-Lin Liu Re Xia 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第1期62-72,共11页
In this study, we developed a general method to analytically tackle a kind of movable boundary problem from the viewpoint of energy variation. Having grouped the adhesion of a micro-beam, droplet and carbon nanotube ... In this study, we developed a general method to analytically tackle a kind of movable boundary problem from the viewpoint of energy variation. Having grouped the adhesion of a micro-beam, droplet and carbon nanotube (CNT) ring on a substrate into one framework, we used the developed line of reasoning to investigate the adhesion behaviors of these systems. Based upon the derived governing equations and transversality conditions, explicit solutions involving the critical parameters and morphologies for the three systems are successfully obtained, and then the parameter analogies and common characteristics of them are thor- oughly investigated. The presented method has been verified via the concept of energy release rate in fracture mechanics. Our analyses provide a new approach for exploring the mechanism of different systems with similarities as well as for understanding the unity of nature. The analysis results may be beneficial for the design of nano-structured materi- als, and hold potential for enhancing their mechanical, chemical, optical and electronic properties. 展开更多
关键词 Variational theory - Transversality condition Beam adhesion Droplet adhesion Carbon nanotube ring adhesion
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Structural, mechanical, and electronic properties of 25 kinds of Ⅲ–Ⅴbinary monolayers: A computational study with first-principles calculation 被引量:2
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作者 Xue-Fei Liu Zi-Jiang Luo +5 位作者 Xun Zhou Jie-Min Wei Yi Wang Xiang Guo Bing Lv Zhao Ding 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第8期258-269,共12页
Using first-principle calculations, we investigate the mechanical, structural, and electronic properties and formation energy of 25 kinds of Ⅲ–V binary monolayers in detail. A relative radius of the binary compound ... Using first-principle calculations, we investigate the mechanical, structural, and electronic properties and formation energy of 25 kinds of Ⅲ–V binary monolayers in detail. A relative radius of the binary compound according to the atomic number in the periodic table is defined, and based on the definition, the 25 kinds of Ⅲ–V binary compounds are exactly located at a symmetric position in a symmetric matrix. The mechanical properties and band gaps are found to be very dependent on relative radius, while the effective mass of holes and electrons are found to be less dependent. A linear function between Young’s modulus and formation energy is fitted with a linear relation in this paper. The change regularity of physical properties of B–V(V = P, As, Sb, Bi) and Ⅲ–N(Ⅲ = Al, Ga, In, Tl) are found to be very different from those of other Ⅲ–V binary compounds. 展开更多
关键词 DENSITY FUNCTIONAL theory -Ⅴbinary monolayers BAND structure MECHANICAL properties
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Bayesian Markov chain Monte Carlo inversion for anisotropy of PP-and PS-wave in weakly anisotropic and heterogeneous media 被引量:4
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作者 Xinpeng Pan Guangzhi Zhang Xingyao Yin 《Earthquake Science》 CSCD 2017年第1期33-46,共14页
A single set of vertically aligned cracks embedded in a purely isotropic background may be con- sidered as a long-wavelength effective transversely iso- tropy (HTI) medium with a horizontal symmetry axis. The crack-... A single set of vertically aligned cracks embedded in a purely isotropic background may be con- sidered as a long-wavelength effective transversely iso- tropy (HTI) medium with a horizontal symmetry axis. The crack-induced HTI anisotropy can be characterized by the weakly anisotropic parameters introduced by Thomsen. The seismic scattering theory can be utilized for the inversion for the anisotropic parameters in weakly aniso- tropic and heterogeneous HTI media. Based on the seismic scattering theory, we first derived the linearized PP- and PS-wave reflection coefficients in terms of P- and S-wave impedances, density as well as three anisotropic parameters in HTI media. Then, we proposed a novel Bayesian Mar- kov chain Monte Carlo inversion method of PP- and PS- wave for six elastic and anisotropic parameters directly. Tests on synthetic azimuthal seismic data contaminated by random errors demonstrated that this method appears more accurate, anti-noise and stable owing to the usage of the constrained PS-wave compared with the standards inver- sion scheme taking only the PP-wave into account. 展开更多
关键词 Crack-induced anisotropy Seismic scattering theory HTI media PP- and PS-wave - Bayesian Markov chain Monte Carlo inversion
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Nanoscale mass sensing based on vibration of single-layered graphene sheet in thermal environments 被引量:2
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作者 S.Ahmad Fazelzadeh Esmaeal Ghavanloo 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2014年第1期84-91,共8页
Based on vibration analysis, single-layered graphene sheet (SLGS) with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysuppo... Based on vibration analysis, single-layered graphene sheet (SLGS) with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysupported configuration. Based on the nonlocal plate the- ory which incorporates size effects into the classical theory, closed-form expressions lot the frequencies and relative fre- quency shills of SLGS-based mass sensor are derived using the Galerkin method. The suggested model is justified by a good agreement between the results given by the present model and available data in literature. The effects of tem- perature difference, nonlocal parameter, the location of the nanoparticle and the number of nanoparticles on the relative frequency shift of the mass sensor are also elucidated. The obtained results show that the sensitivity of the SLGS- based mass sensor increases with increasing temperature difference. 展开更多
关键词 Vibration - Single-layered graphene sheet. Ther- mal environment - Nonlocal elasticity theory Relative frequency shift
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两个乘积因子的σ-仿紧空间的乘积定理(Ⅱ)
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作者 李放 《贵州师范大学学报(自然科学版)》 CAS 2001年第4期65-68,共4页
主要证明下述定理 :如果X是仿紧的C -分散空间 ,则X×Y是σ -仿紧的当且仅当Y是σ -仿紧的。此外 ,我们还指出 ;σ
关键词 C-分散空间 σ-仿紧空间 σ-序列meso 拓扑空间 乘积定理 覆盖刻画
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DFT Investigation of O_2 Adsorption on Si(001)-(2×2×1):H
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作者 邓小燕 杨春 +2 位作者 周明秀 郁卫飞 李金山 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第6期485-487,共3页
A novel model was developed to theoretically evaluate the 02 adsorption on H-terminated Si(001)-(2×2×1) surface. The periodic boundary condition, the ultrasoft pseudopotentials technique based on density... A novel model was developed to theoretically evaluate the 02 adsorption on H-terminated Si(001)-(2×2×1) surface. The periodic boundary condition, the ultrasoft pseudopotentials technique based on density functional theory (DFT) with generalized gradient approxi,natior, (GGA) functional were applied in our ab initio calculations. By analyzing bonding energy oil site, the favourable adsorption site was determined. The calculations also predicted that the adsorption products should be Si=O and H2O. This theoretical study snpported the reaction mechanism provided by Kovalev et al, The results were also a base for further investigation of some more complex systems such as the oxida.tion on porous silicon surface. 展开更多
关键词 Si(001)-(2×2×1):H O2 Density functional theory (DFT) Adsorption site
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