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喷射混凝土力学性能试验研究及预测模型建立 预览
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作者 王家滨 牛荻涛 《硅酸盐通报》 CAS 北大核心 2019年第1期125-131,共7页
以喷射混凝土单层永久衬砌隧道为背景,采用干喷大板法,开展喷射混凝土力学性能试验。以宝鸡至兰州高速铁路麦积山隧道衬砌喷射混凝土配合比为基础,考虑水胶比、粉煤灰和钢纤维影响,研究喷射混凝土抗压强度和劈裂抗拉强度经时变化规律,... 以喷射混凝土单层永久衬砌隧道为背景,采用干喷大板法,开展喷射混凝土力学性能试验。以宝鸡至兰州高速铁路麦积山隧道衬砌喷射混凝土配合比为基础,考虑水胶比、粉煤灰和钢纤维影响,研究喷射混凝土抗压强度和劈裂抗拉强度经时变化规律,建立相应的预测模型。结果表明:喷射混凝土早龄期强度较高。随着龄期增大,同配合比模筑混凝土强度增大并超过喷射混凝土,且二者差值逐渐增大。水胶比增大及钢纤维掺量减小,喷射混凝土强度减小;随粉煤灰掺量增大,强度先增大后减小。采用13组数据对抗压强度模型进行验证,其相对偏差的标准差为5.55,说明模型具有较好的适用性。喷射混凝土抗压强度和劈裂抗拉强度均呈正态分布,且二者之间呈指数关系。 展开更多
关键词 喷射混凝土 抗压强度 劈裂抗拉强度 经时变化 预测模型
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时间依赖路网中反向k近邻查询 预览
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作者 李佳佳 沈盼盼 +1 位作者 夏秀峰 刘向宇 《计算机科学》 CSCD 北大核心 2019年第1期232-237,共6页
在现存的反向k近邻查询方案中,比较高效的研究大多集中在欧氏空间或者静态路网,对时间依赖路网中的反向k近邻查询的研究相对较少。已有算法在兴趣点密度稀疏或者k值较大时,查询效率较低。对此,提出了基于子网划分的反向k近邻查询算法mTD... 在现存的反向k近邻查询方案中,比较高效的研究大多集中在欧氏空间或者静态路网,对时间依赖路网中的反向k近邻查询的研究相对较少。已有算法在兴趣点密度稀疏或者k值较大时,查询效率较低。对此,提出了基于子网划分的反向k近邻查询算法mTD-SubG。首先,将整个路网划分为大小相同的子网,通过子网的边界节点向其他子网进行扩展,加快对路网中兴趣点的查找速度;其次,利用剪枝技术缩小路网的扩展范围;最后,利用已有时间依赖路网下的近邻查询算法,判定查找到的兴趣点是否为反向k近邻结果。实验中将mTD-SubG算法与已有算法mTD-Eager进行对比,结果表明mTD-SubG算法的响应时间比mTD-Eager算法减少了85.05%,遍历节点个数比mTD-Eager算法减少了51.40%。 展开更多
关键词 时间依赖 路网 反向k近邻(RkNN) mTD-SubG算法
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求解Time-dependent Stokes方程的含参数双预优迭代算法
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作者 李晓莎 沈海龙 邵新慧 《数学的实践与认识》 北大核心 2019年第11期165-175,共11页
Time-dependent Stokes方程在离散动力学系统和科学计算中具有非常重要的作用,而它的求解非常困难.针对Time-dependent Stokes方程利用双预优方法构造了一种新型的含参数双预优迭代解法,并给出了新方法的收敛性分析,同时还讨论了参数的... Time-dependent Stokes方程在离散动力学系统和科学计算中具有非常重要的作用,而它的求解非常困难.针对Time-dependent Stokes方程利用双预优方法构造了一种新型的含参数双预优迭代解法,并给出了新方法的收敛性分析,同时还讨论了参数的取值范围.最后用数值算例又验证了新方法的可行性和有效性. 展开更多
关键词 TIME-DEPENDENT STOKES方程 双预优方法 微分代数方程 收敛域
Effect of Beam Current and Diameter on Electron Probe Microanalysis of Carbonate Minerals
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作者 Xing Zhang Shuiyuan Yang +3 位作者 He Zhao Shaoyong Jiang Ruoxi Zhang Jing Xie 《地球科学学刊:英文版》 SCIE CAS CSCD 2019年第4期834-842,共9页
The effect of operating conditions on the time-dependent X-ray intensity variation is of great importance for the optimal EPMA conditions for accurate determinations of various elements in carbonate minerals. Beam dia... The effect of operating conditions on the time-dependent X-ray intensity variation is of great importance for the optimal EPMA conditions for accurate determinations of various elements in carbonate minerals. Beam diameters of 0, 1, 2, 5, 10, 15, and 20 μm, and beam currents of 3, 5, 10, 20,and 50 nA were tested. Ca, Mg, Zn, and Sr were found to be more sensitive to electron beam irradiation as compared to other elements, and small currents and large beam diameters minimized the timedependent X-ray intensity variations. We determined the optimal EPMA operating conditions for elements in carbonate: 10 μm and 5 nA for calcite;10 μm and 10 nA for dolomite;5 μm and 10 nA or 10 μm and 20 nA for strontianite;and 20 nA and 5 μm for other carbonate. Elements sensitive to electron beam irradiation should be determined first. In addition, silicate minerals are preferred as standards rather than carbonate minerals. 展开更多
关键词 CARBONATE minerals:electron probe MICROANALYSIS characteristic X-ray TIME-DEPENDENT intensity BEAM current BEAM DIAMETER
Non-adiabatic quantum dynamical studies of Na(3p) + HD(v = 1, j5) = 0)→NaH/NaD + D/H reaction
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作者 温月佩 布仁巴雅尔 陈茂笃 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期169-175,共7页
Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-depende... Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels(NaH/NaD+D/H)are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering. 展开更多
关键词 TIME-DEPENDENT wave packet method NON-ADIABATIC REACTION integral CROSS SECTION differential CROSS SECTION
Efficient solver for time-dependent Schrodinger equation with interaction between atoms and strong laser field
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作者 周胜鹏 刘爱华 +2 位作者 刘芳 王春成 丁大军 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第8期66-72,共7页
We present a parallel numerical method of simulating the interaction of atoms with a strong laser field by solving the time-depending Schrodinger equation(TDSE)in spherical coordinates.This method is realized by combi... We present a parallel numerical method of simulating the interaction of atoms with a strong laser field by solving the time-depending Schrodinger equation(TDSE)in spherical coordinates.This method is realized by combining constructing block diagonal matrices through using the real space product formula(RSPF)with splitting out diagonal sub-matrices for short iterative Lanczos(SIL)propagator.The numerical implementation of the solver guarantees efficient parallel computing for the simulation of real physical problems such as high harmonic generation(HHG)in these interaction systems. 展开更多
关键词 TIME-DEPENDENT SCHRODINGER equation STRONG laser FIELDS Parallel numerical SOLVER
一种含时量子输运的理论和应用 预览
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作者 程霄 谢航 《物理学进展》 CSCD 北大核心 2019年第4期119-136,共18页
含时量子输运研究的是开放体系中的电子波的演化问题。这类问题,由于电极耗散等外界环境的影响,中心体系内的电子运动受外场驱动时,其运动状况不光取决于当下时刻,还和过去一段时刻的历史状况求和相关。这是一种非马尔科夫过程,数学上... 含时量子输运研究的是开放体系中的电子波的演化问题。这类问题,由于电极耗散等外界环境的影响,中心体系内的电子运动受外场驱动时,其运动状况不光取决于当下时刻,还和过去一段时刻的历史状况求和相关。这是一种非马尔科夫过程,数学上也比较难以求解。本文以非平衡格林函数为基础,详细介绍了一类新的求解含时量子输运的方法:密度矩阵的运动方程方法。这种方法理论上步骤清晰,易于数值计算,特别是可以推广到较大体系的计算。另外,本文还介绍了其他一些含时输运方法,并举例说明了这类含时输运理论的应用,如石墨烯等二维材料中的瞬态电流,有多体作用的开放量子点体系中的电子动力学等。 展开更多
关键词 量子输运 含时 运动方程 非平衡格林函数理论 复数吸收势 自能
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Long-term deformation analysis of Shuibuya concrete face rockfill dam based on response surface method and improved genetic algorithm 预览
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作者 Fu-hai Yao Shao-heng Guan +4 位作者 He Yang Yuan Chen Huan-feng Qiu Gang Ma Qi-wen Liu 《水科学与水工程:英文版》 EI CAS CSCD 2019年第3期196-204,共9页
Due to the size effects of rockfill materials, the settlement difference between numerical simulation and in situ monitoring of rockfill dams is a topic of general concern.The constitutive model parameters obtained fr... Due to the size effects of rockfill materials, the settlement difference between numerical simulation and in situ monitoring of rockfill dams is a topic of general concern.The constitutive model parameters obtained from laboratory triaxial tests often underestimate the deformation of high rockfill dams.Therefore, constitutive model parameters obtained by back analysis were used to calculate and predict the long-term deformation of rockfill dams.Instead of using artificial neural networks (ANNs), the response surface method (RSM) was employed to replace the finite element simulation used in the optimization iteration.Only 27 training samples were required for RSM, improving computational efficiency compared with ANN, which required 300 training samples.RSM can be used to describe the relationship between the constitutive model parameters and dam settlements.The inversion results of the Shuibuya concrete face rockfill dam (CFRD) show that the calculated settlements agree with the measured data, indicating the accuracy and efficiency of RSM. 展开更多
关键词 SHUIBUYA ROCKFILL DAM Parameter BACK analysis Response surface method Duncan EB model TIME-DEPENDENT deformation
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Exploring the effect of aggregation-induced emission on the excited state intramolecular proton transfer for a bis-imine derivative by quantum mechanics and our own n-layered integrated molecular orbital and molecular mechanics calculations
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作者 赵慧芳 孙朝范 +2 位作者 刘晓春 尹航 石英 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期645-649,共5页
We theoretically investigate the excited state intramolecular proton transfer(ESIPT) behavior of the novel fluorophore bis-imine derivative molecule HNP which was designed based on the intersection of 1-(hydrazonometh... We theoretically investigate the excited state intramolecular proton transfer(ESIPT) behavior of the novel fluorophore bis-imine derivative molecule HNP which was designed based on the intersection of 1-(hydrazonomethyl)-naphthalene-2-ol and 1-pyrenecarboxaldehyde. Especially, the density functional theory(DFT) and time-dependent density functional theory(TDDFT) methods for HNP monomer are introduced. Moreover, the 'our own n-layered integrated molecular orbital and molecular mechanics'(ONIOM) method(TDDFT:universal force field(UFF)) is used to reveal the aggregation-induced emission(AIE) effect on the ESIPT process for HNP in crystal. Our results confirm that the ESIPT process happens upon the photoexcitation for the HNP monomer and HNP in crystal, which is distinctly monitored by the optimized geometric structures and the potential energy curves. In addition, the results of potential energy curves reveal that the ESIPT process in HNP will be promoted by the AIE effect. Furthermore, the highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) for the HNP monomer and HNP in crystal have been calculated. The calculation demonstrates that the electron density decrease of proton donor caused by excitation promotes the ESIPT process. In addition, we find that the variation of atomic dipole moment corrected Hirshfeld population(ADCH) charge for proton acceptor induced by the AIE effect facilitates the ESIPT process. The results will be expected to deepen the understanding of ESIPT dynamics for luminophore under the AIE effect and provide insight into future design of high-efficient AIE compounds. 展开更多
关键词 time-dependent density functional theory(TDDFT) METHOD excited state intramolecular proton transfer(ESIPT) our own n-layered integrated MOLECULAR orbital and MOLECULAR mechanics(ONIOM) METHOD potential energy curves atomic dipole moment corrected Hirshfeld population(ADCH) charge
Utilization of Maxwell-Cattaneo law for MHD swirling flow through oscillatory disk subject to porous medium 预览
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作者 A. RAUF Z. ABBAS S. A. SHEHZAD 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第6期837-850,共14页
The present study aims to investigate the salient features of incompressible, hydromagnetic, three-dimensional flow of viscous fluid subject to the oscillatory motion of a disk. The rotating disk is contained in a por... The present study aims to investigate the salient features of incompressible, hydromagnetic, three-dimensional flow of viscous fluid subject to the oscillatory motion of a disk. The rotating disk is contained in a porous medium. Furthermore, a time-invariant version of the Maxwell-Cattaneo law is implemented in the energy equation. The flow problem is normalized by obtaining similarity variables. The resulting nonlinear system is solved numerically using the successive over-relaxation method. The main results are discussed through graphical representations and tables. It is perceived that the thermal relaxation time parameter decreases the temperature curves and increases the heat trans- fer rate. The oscillatory curves for the velocity field demonstrate a decreasing tendency with the increasing porosity parameter values. Two- and three-dimensional flow phenom- ena are also shown through graphical results. 展开更多
关键词 time-dependent flow OSCILLATORY DISK porous medium magnetohydrody-namic (MHD) Maxwell-Cattaneo LAW numerical solution
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Stability of LRS Bianchi type-I cosmological models in f(R,T)-gravity
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作者 Umesh Kumar Sharma Rashid Zia +1 位作者 Anirudh Pradhan Aroon Beesham 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2019年第4期63-76,共14页
This paper examines the stability of the transition from the early decelerating stage of the Universe to the recent accelerating stage for the perfect fluid cosmological locally rotationally symmetric(LRS) Bianchi-I m... This paper examines the stability of the transition from the early decelerating stage of the Universe to the recent accelerating stage for the perfect fluid cosmological locally rotationally symmetric(LRS) Bianchi-I model in f(R, T) theory. To determine the solution of field equations, the idea of a timevarying deceleration parameter(DP) which yields a scale factor, for which the Universe attains a phase transition scenario and is consistent with recent cosmological observations, is used. The time-dependent DP yields a scale factor a=exp■, where β and k are respectively arbitrary and integration constants. By using the recent constraints(H0 = 73.8, and q0 =-0.54) from Type Ia Supernova(SN Ia) data in combination with Baryonic Acoustic Oscillations(BAO) and Cosmic Microwave Background(CMB) observations(Giostri et al.), we obtain the values of β= 0.0062 and k = 0.000016 for which we have derived a cosmological model from the early decelerated phase to the present accelerating phase. By applying other recent constraints(H0 = 73.8, q0 =-0.73) from SNe Ia Union data(Cunha), we obtain the values of β= 0.0036 and k = 0.000084 for which we have derived a cosmological model in the accelerating phase only. We have compared both models with experimental data. The stability of the background solution has been examined also for the metric perturbations alongside the properties of future singularities in a Universe ruled by dark energy with phantom type fluid. We demonstrate the presence of a stable fixed point with a condition of state ω<-1 and numerically affirm this is really a late-time attractor in the ghost overwhelmed Universe. Some physical and geometric properties of the model are found and examined. 展开更多
关键词 LRS Bianchi-I UNIVERSE Time-dependent DECELERATION parameter f(R T) GRAVITY theory Transit UNIVERSE
Some contributions to mechanical behaviors of lacustrine deposit in Bogota, Colombia 预览
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作者 Bernardo Caicedo Cristhian Mendoza +1 位作者 Arcesio Lizcano Fernando Lopez-Caballero 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第4期837-849,共13页
This paper presents the mechanical behaviors of the lacustrine deposit,a representative soil in Bogota,Colombia.Initially,the physical characterization of the deposit is performed via laboratory tests (grain size dist... This paper presents the mechanical behaviors of the lacustrine deposit,a representative soil in Bogota,Colombia.Initially,the physical characterization of the deposit is performed via laboratory tests (grain size distribution,scanning electron microscopy,Atterberg limits and water content).This characterization intends to explain the special characteristics of the mechanical behaviors of this soil.Then,various triaxial tests are carried out with controlled loading path,strain rate change,relaxation,extensile stress,and cyclic loading.The test results reveal the shape of the yield curve for Bogotá soil (in a natural state),and also show that an increasing effect of the strain rate depends on the liquid limit.This effect is also preserved with extensile stresses (which are poorly studied in soil mechanics).Finally,other effects,such as the loss of structure in the reconstituted samples and the effect of shear modulus at low strains,are studied for Bogota soil. 展开更多
关键词 Cyclic TRIAXIAL tests TRIAXIAL compression test TIME-DEPENDENT response LACUSTRINE soils Soil COMPRESSIBILITY Yield CURVE
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Dynamic simulation of the effect of time-dependent variation of pH on response variable of the tailing thickener of coal washing plant 预览
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作者 Mehdi Rahimi Ali Akbar Abdollahzadeh Bahram Rezai 《国际煤炭科学技术学报:英文版》 2019年第1期127-137,共11页
Dynamic simulation approach can be used for understanding the nonlinear behavior in mineral processing circuits. In this study, the gel point, the main parameters of batch flux density function and the main parameters... Dynamic simulation approach can be used for understanding the nonlinear behavior in mineral processing circuits. In this study, the gel point, the main parameters of batch flux density function and the main parameters of effective solid stress were determined at different conditions (pH, flocculant dosage and particle size). Therefore, the main parameters of phenome no logical model of sedimentation and thickening were determined as a functio n of particle size, pH and flocculant dosages using the result of experimental tests and Curve expert professional software. Then, the dynamic simulation was carried out for the industrial thickener of coal washing plant and the time-dependent variation of response variables was investigated by time-dependent variation of pH of input feed to thickener using the obtained equations. It was observed that it is possible to predict the thickener behavior as a function of time for time dependent variation of pH of input feed to the thickener of coal washing plant using obtained equations that it was not possible using phenomenological model of thickener alone. 展开更多
关键词 Dynamic simulation DEWATERING Ideal continuous THICKENER THICKENER behavior TIME-DEPENDENT VARIATION of PH
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Developing an Instantaneous Response Surface Method t-IRS for Time-Dependent Reliability Analysis
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作者 Junxiang Li Jianqiao Chen +2 位作者 Junhong Wei Xiaosheng Zhang Ben Han 《固体力学学报:英文版》 SCIE EI CSCD 2019年第4期446-462,共17页
In practical engineering, many uncertain factors in loading or degradation of material properties may vary with time. Stochastic process modeling constitutes a suitable approach for describing these time-dependent unc... In practical engineering, many uncertain factors in loading or degradation of material properties may vary with time. Stochastic process modeling constitutes a suitable approach for describing these time-dependent uncertainties. By adopting this approach, however, the timedependent reliability calculation is a great challenge owing to the complexity and the huge computational burden. This paper presents a new instantaneous response surface method t-IRS for time-dependent reliability analysis. Different from the adaptive extreme response surface approach, the proposed method does not need to build and update surrogate models separately at each time node. It first uses the expansion optimal linear estimation method to discretize the stochastic processes into a set of independent standard normal variables together with some deterministic functions of time. Time is then treated as an independent one-dimensional variable. Next, initial samples are generated by Latin hypercube sampling, and the corresponding response values are calculated and utilized to construct an instantaneous response surrogate model of the Kriging type. The active learning method is applied to update the Kriging surrogate model until satisfactory accuracy is achieved. Finally, the instantaneous response surrogate model is used to compute the time-dependent reliability via Monte Carlo simulation. Four case studies are utilized to demonstrate the effectiveness of the ^-IRS method for time-dependent reliability analysis. 展开更多
关键词 TIME-DEPENDENT reliability STOCHASTIC process Instantaneous response surface METHOD i-IRS Expansion optimal linear estimation METHOD KRIGING surrogate model
Reaction mechanism of D + ND→N + D2 and its state-to-state quantum dynamics
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作者 许婷 赵娟 +1 位作者 王宪龙 孟庆田 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期173-178,共6页
The quantum state-to-state calculations of the D + ND→N + D2 reaction are performed on a potential energy surface of 4 A’’ state. The state-resolved integral and differential cross sections and product state distri... The quantum state-to-state calculations of the D + ND→N + D2 reaction are performed on a potential energy surface of 4 A’’ state. The state-resolved integral and differential cross sections and product state distributions are calculated and discussed. It is found that the rotational distribution, rather than the vibrational distribution, of the product has an obvious inversion. Due to the fact that it is a small-impact-parameter collision, its product D2 is mainly dominated by rebound mechanism, which can lead to backward scattering at low collision energy. As the collision energy increases, the forward scattering and sideward scattering begin to appear. In addition, the backward collision is also found to happen at high collision energy, through which we can know that both the rebound mechanism and stripping mechanism exist at high collision energy. 展开更多
关键词 state-to-state quantum dynamics TIME-DEPENDENT wave PACKET D+ND differential cross section
运动状态下全尾砂胶结料浆流变参数时变性研究 预览
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作者 寇云鹏 齐兆军 +4 位作者 盛宇航 杜加法 荆晓东 宋泽普 杨纪光 《有色金属:矿山部分》 2019年第1期15-19,共5页
全尾砂胶结料浆在管路输送过程中流变参数具有时变性。以连续搅拌方式模拟料浆在输送过程中的运动状态,借助Brookfield流变仪研究了不同质量浓度和灰砂比条件下,搅拌时间对料浆流变参数的影响规律及作用机理。研究结果表明:1)当搅拌时... 全尾砂胶结料浆在管路输送过程中流变参数具有时变性。以连续搅拌方式模拟料浆在输送过程中的运动状态,借助Brookfield流变仪研究了不同质量浓度和灰砂比条件下,搅拌时间对料浆流变参数的影响规律及作用机理。研究结果表明:1)当搅拌时间逐渐增加时,灰砂比1∶5,质量浓度分别为72%、74%和76%的全尾砂胶结料浆其屈服应力和黏性系数均随之增大,且料浆质量浓度越高,搅拌时间对料浆流变参数的影响越显著;2)质量浓度74%,灰砂比分别为1∶5、1∶10和1∶15的全尾砂胶结料浆屈服应力和黏性系数也随搅拌时间的增加而增大。料浆流变参数增大的主要原因为:料浆中水泥水化反应产生的具有凝聚网络结构的凝胶成分含量随时间的增加而不断增加。 展开更多
关键词 全尾砂胶结料浆 流变参数 运动状态 时变性
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Time-varying nonlinear dynamics of a deploying piezoelectric laminated composite plate under aerodynamic force 预览
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作者 S.F.Lu W.Zhang X.J.Song 《力学学报:英文版》 SCIE EI CAS CSCD 2018年第2期303-314,共12页
Using Reddy’s high-order shear theory for laminated plates and Hamilton’s principle,a nonlinear partial differential equation for the dynamics of a deploying cantilevered piezoelectric laminated composite plate,unde... Using Reddy’s high-order shear theory for laminated plates and Hamilton’s principle,a nonlinear partial differential equation for the dynamics of a deploying cantilevered piezoelectric laminated composite plate,under the combined action of aerodynamic load and piezoelectric excitation,is introduced.Two-degree of freedom(DOF)nonlinear dynamic models for the time-varying coefficients describing the transverse vibration of the deploying laminate under the combined actions of a first-order aerodynamic force and piezoelectric excitation were obtained by selecting a suitable time-dependent modal function satisfying the displacement boundary conditions and applying second-order discretization using the Galerkin method.Using a numerical method,the time history curves of the deploying laminate were obtained,and its nonlinear dynamic characteristics,including extension speed and different piezoelectric excitations,were studied.The results suggest that the piezoelectric excitation has a clear effect on the change of the nonlinear dynamic characteristics of such piezoelectric laminated composite plates.The nonlinear vibration of the deploying cantilevered laminate can be effectively suppressed by choosing a suitable voltage and polarity. 展开更多
关键词 Deploying PIEZOELECTRIC laminated composite PLATE TIME-VARYING nonlinear dynamics THIRD-ORDER shear deformation PLATE theory TIME-DEPENDENT MODAL function Aerodynamic force
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大高宽比支撑体系在渐变超高大悬挑结构中的关键技术研究 预览
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作者 文秋实 《福建建设科技》 2018年第2期44-47,共4页
在文锦渡口岸工程的联检综合楼中,采用了一种构造复杂、造型特异的结构设计方案,本文将之命名为"渐变超高大悬挑结构"。通过方案比选优选确定该结构的支撑体系方案,建立支撑体系的有限元模型,根据结构与支撑体系共同工作的时... 在文锦渡口岸工程的联检综合楼中,采用了一种构造复杂、造型特异的结构设计方案,本文将之命名为"渐变超高大悬挑结构"。通过方案比选优选确定该结构的支撑体系方案,建立支撑体系的有限元模型,根据结构与支撑体系共同工作的时变性原理,分析有限元模型的内力计算数据,找出大高宽比支撑体系的构造缺陷薄弱点并加以优化,保证了支撑体系的稳定承载力,揭示了不同施工期多层悬挑结构支撑体系的内力变化主要规律。 展开更多
关键词 时变性 有限元 支撑体系
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基于公共交通的高精度时空可达模型与算法 预览
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作者 董绍轩 张彤 《计算机系统应用》 2017年第3期175-181,共7页
公共交通作为我国城市居民的主要出行方式,对其可达性的研究具有非常重要的价值和意义.然而,由于站点位置、固定线路、时刻表等条件的限制,使得公共交通可达性的研究具有一定的特殊性.针对已有研究存在的可达精度不高或者无法进行大规... 公共交通作为我国城市居民的主要出行方式,对其可达性的研究具有非常重要的价值和意义.然而,由于站点位置、固定线路、时刻表等条件的限制,使得公共交通可达性的研究具有一定的特殊性.针对已有研究存在的可达精度不高或者无法进行大规模可达分析等问题,基于路网、公交网络、地铁网络和时刻表信息建立高精度时空网络模型,设计时间依赖条件下枢纽站点和A*算法相结合的快速公交换乘算法.以武汉市为例,对其进行大规模高精度时空可达分析,证明了模型的可靠性和算法的高效性. 展开更多
关键词 公共交通 时空可达 模型 算法 时间依赖
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考虑时间效应边界面模型在地铁工程中的应用 被引量:1
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作者 骆俊晖 缪林昌 +2 位作者 李仞玨 石文博 王刚 《岩石力学与工程学报》 CSCD 北大核心 2017年第6期1531-1541,共11页
为了真实刻画地铁移动荷载低振幅、高振次特征,准确计算软土地铁地基在运营期的长期沉降,需要提出能描述低应力水平下土体动蠕变特性的本构模型。据此,基于边界面本构模型,结合Mesri蠕变模型,建立考虑时间效应的边界面本构模型。随后,... 为了真实刻画地铁移动荷载低振幅、高振次特征,准确计算软土地铁地基在运营期的长期沉降,需要提出能描述低应力水平下土体动蠕变特性的本构模型。据此,基于边界面本构模型,结合Mesri蠕变模型,建立考虑时间效应的边界面本构模型。随后,为了开发ABAQUS材料子程序,采用应力积分算法对本构模型进行推导,借鉴阻止应变法进行算法的优化,可以使计算间隔缩短,总迭代次数增多,更易收敛。采用提出的本构模型和南京软土GDS动三轴试验获得的相关参数进行数值模拟计算,并进行试验对比,验证本构模型的有效性。同时,将开发的本构模型嵌入数值模拟计算中,设置黏弹性人工边界,进行三维地铁有限元数值模拟分析。结果表明:(1)基于阻止应变法的优化算法可以进行推广使用;(2)考虑时间效应的边界面本构模型适合描述软土动蠕变特性,能有效预测软土在低振幅地铁移动荷载作用下的累积沉降。研究对理论研究和实际工程具有重要的指导意义。 展开更多
关键词 土力学 软土 地铁 循环荷载 边界面模型 时间效应 ABAQUS
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