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CONVERGENCE RATES TO NONLINEAR DIFFUSIVE WAVES FOR SOLUTIONS TO NONLINEAR HYPERBOLIC SYSTEM 预览
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作者 耿世锋 唐炎娟 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第1期46-56,共11页
This article is involved with the asymptotic behavior of solutions for nonlinear hyperbolic system with external friction. The global existence of classical solutions is proven,and L~p convergence rates are obtained. ... This article is involved with the asymptotic behavior of solutions for nonlinear hyperbolic system with external friction. The global existence of classical solutions is proven,and L~p convergence rates are obtained. Compared with the results obtained by Hsiao and Liu, better convergence rates are obtained in this article. 展开更多
关键词 CONVERGENCE rates NONLINEAR diffusion WAVES NONLINEAR HYPERBOLIC system external FRICTION
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Nonlinear free vibration of piezoelectric cylindrical nanoshells 预览
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作者 Yanqing WANG Yunfei LIU J. W. ZU 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第5期601-620,共20页
The nonlinear vibration characteristics of the piezoelectric circular cylindri- cal nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into... The nonlinear vibration characteristics of the piezoelectric circular cylindri- cal nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into account. Based on the nonlocal elastic- ity theory and Donnell’s nonlinear shell theory, the nonlinear governing equations and the corresponding boundary conditions are derived by employing Hamilton’s principle. Then, the Galerkin method is used to transform the governing equations into a set of ordinary differential equations, and subsequently, the multiple-scale method is used to obtain an approximate analytical solution. Finally, an extensive parametric study is conducted to examine the effects of the nonlocal parameter, the external electric potential, the temperature rise, and the Winkler-Pasternak foundation parameters on the nonlinear vibration characteristics of circular cylindrical piezoelectric nanoshells. 展开更多
关键词 PIEZOELECTRIC CYLINDRICAL NANOSHELL NONLINEAR vibration Donnell's NONLINEAR shell THEORY nonlocal elasticity THEORY multiple-scale method size effect
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Targeted energy transfer of a parallel nonlinear energy sink 预览
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作者 Yimin WEI Sha WEI +3 位作者 Qianlong ZHANG Xinjian DONG Zhike PENG Wenming ZHANG 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第5期621-630,共10页
A parallel nonlinear energy sink (NES) is proposed and analyzed. The parallel NES is composed of a vibro-impact (VI) NES and a cubic NES. The dynamical equation is given, and the essential analytical investigation is ... A parallel nonlinear energy sink (NES) is proposed and analyzed. The parallel NES is composed of a vibro-impact (VI) NES and a cubic NES. The dynamical equation is given, and the essential analytical investigation is carried out to deal with the cubic nonlinearity and impact nonlinearity. Multiple time-scale expansion is introduced, and the zeroth order is derived to give a rough outline of the system. The underlying Hamilton dynamic equation is given, and then the optimal stiffness is expressed. The clearance is regarded as a critical factor for the VI. Based on the periodical impact treatment by analytical investigation, the relationships of the cubic stiffness, the clearance, and the zeroth-order attenuation amplitude of the linear primary oscillator (LPO) are obtained. A cubic NES under the optimal condition is compared with the parallel NES. Harmonic signals, harmonic signals with noises, and the excitation generated by a second-order filter are considered as the potential excitation forces on the system. The targeted energy transfer (TET) in the designed parallel NES is shown to be more efficient. 展开更多
关键词 TARGETED ENERGY transfer (TET) NONLINEAR ENERGY sink (NES) NONLINEAR VIBRATION ABSORBER impact VIBRATION reduction
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Prescribed Performance Finite-Time Tracking Control for Uncertain Nonlinear Systems
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作者 JING Yuanwei LIU Yang ZHOU Shaowei 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第3期803-817,共15页
This work investigates the finite-time tracking control problem for a class of uncertain strict-feedback nonlinear systems from a new perspective. First, a novel concept called finite-time performance function (FTPF) ... This work investigates the finite-time tracking control problem for a class of uncertain strict-feedback nonlinear systems from a new perspective. First, a novel concept called finite-time performance function (FTPF) is defined. Further, a new sufficien t condition of finite-time st ability is derived and the tracking error can converge to a predefined region within a finite-time interval. The design process of the proposed technique is simpler. Finally, four simulation examples are carried out to illustrate the effectiveness of presented method. 展开更多
关键词 FINITE-TIME BOUNDEDNESS PRESCRIBED PERFORMANCE control UNCERTAIN nonlinear systems
Nonlinear energy harvesting based on a modified snap-through mechanism 预览
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作者 Zeqi LU Ke LI +1 位作者 Hu DING Liqun CHEN 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第1期167-180,共14页
A modified snap-through mechanism is used in an electromagnetic energy harvester to improve its effectiveness.It mainly comprises three springs that are con-figured so that the potential energy of the system has two s... A modified snap-through mechanism is used in an electromagnetic energy harvester to improve its effectiveness.It mainly comprises three springs that are con-figured so that the potential energy of the system has two stable equilibrium points.In particular,the small vibration behavior of the harvester around one of the equilibriums is of interest.A multi-scale method (MSM)is used to analyze the frequency response curve.Two snap-through mechanisms are considered.One has both horizontal and verti-cal springs.The other has only horizontal springs.The frequency response curves of these two classes are compared under the same excitation and electric loading conditions.The latter exhibits more bending of the frequency response curve than the former one.The results are also validated by some numerical work.The averaged power subject to the Gaussian white noise is calculated numerically,and the results demonstrate that bi-stable energy harvesting with only horizontal springs can outperform the mechanism with both horizontal and vertical springs for the same distance between two equilibriums. 展开更多
关键词 energy HARVESTING NONLINEAR STIFFNESS SNAP-THROUGH RANDOM EXCITATION
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基于波动方程的叠前地震反演 预览
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作者 孙成禹 姚振岸 +1 位作者 伍敦仕 喻志超 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2019年第2期604-618,共15页
随着地震勘探和开发的不断深入,面向地质目标的精细储层预测技术变得越来越重要.由于透射损失、层间多次波、波模式转换以及随机噪声等的影响,观测地震数据和待反演的地下介质属性之间呈现出很强的非线性.考虑到这些非线性,本文基于积... 随着地震勘探和开发的不断深入,面向地质目标的精细储层预测技术变得越来越重要.由于透射损失、层间多次波、波模式转换以及随机噪声等的影响,观测地震数据和待反演的地下介质属性之间呈现出很强的非线性.考虑到这些非线性,本文基于积分波动方程开展叠前地震反演,从观测地震数据中恢复出介质属性和整体波场,其中反演参数是波动方程中的压缩系数、剪切柔度和密度的对比度,相比于常规线性AVO反演的波阻抗弹性参数,它们对流体指示有更强的敏感性.在反演过程中,从平滑的低频背景场出发,交替迭代求解数据方程和目标方程.采用乘性正则化方法于共轭梯度框架下求解反演参数,采用优化的散射级数Neumann序列获得整体波场,这种方法不易陷入局部极值,能收敛到正确解.测井资料和典型山前带模型测试表明,利用上述反演方法能获得高分辨率的深度域地下介质属性,可直接进行储层预测和解释. 展开更多
关键词 散射理论 积分波动方程 非线性 深度域叠前反演 正则化
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Seismic behavior of slab-structural wall junction of RC building 预览
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作者 Snehal Kaushik Kaustubh Dasgupta 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第2期331-349,共19页
In high seismic zone regions, slender reinforced concrete structural walls are commonly used in high-rise buildings as a main lateral load resisting element. These walls are very effective in limiting the lateral drif... In high seismic zone regions, slender reinforced concrete structural walls are commonly used in high-rise buildings as a main lateral load resisting element. These walls are very effective in limiting the lateral drift of the building due to their large in-plane stiffness. However, the presence of floor slabs influences the behavior of the shear wall. Also, the current design requirements do not account for the presence of floor slabs. To understand the behavior of wall-slab junctions and address the shortcomings of the current design requirements, the influence of two parameters, namely(a) aspect ratio and(b) longitudinal reinforcement ratio on the behavior is studied numerically. It is observed that the presence of floor slabs at different levels tends to partition the wall into squat wall panels between two consecutive floors. The wall-slab junctions show large stress concentrations arising from the strut action in the squat panels. It is also observed that the floor slabs can get significantly damaged near the wall-slab junction for lower vertical reinforcement ratios in the wall. Thus, the current codeprescribed minimum reinforcement in shear walls is not sufficient and needs to be revisited at for improved performance. 展开更多
关键词 RC WALL building wall-slab JUNCTION SEISMIC damage nonlinear STATIC analysis
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斜圈弹簧非线性刚度及其结构参数影响分析 预览
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作者 王建平 马世豪 +3 位作者 王东 黄悦 郭梦飞 郝晨星 《机械科学与技术》 CSCD 北大核心 2019年第1期30-36,共7页
斜圈弹簧独特的非线性刚度特性是其在高压电力连接、高性能密封设备中广泛使用的关键所在。本文采用参数化建模思想,以单圈斜圈弹簧为研究对象,建立了一套有效的理论计算斜圈弹簧刚度方法。并对斜圈弹簧结构进行参数化分析,得出每个参... 斜圈弹簧独特的非线性刚度特性是其在高压电力连接、高性能密封设备中广泛使用的关键所在。本文采用参数化建模思想,以单圈斜圈弹簧为研究对象,建立了一套有效的理论计算斜圈弹簧刚度方法。并对斜圈弹簧结构进行参数化分析,得出每个参数对结构刚度的影响。该理论计算弹簧刚度的方法对比于有限元方法计算效率高,并且有助于对斜圈弹簧的非线性机理的认知,对于斜圈弹簧的优化设计、生产与检测提供了理论指导。 展开更多
关键词 斜圈弹簧 刚度计算 非线性 参数化分析
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LARGE TIME BEHAVIOR OF SOLUTION TO NONLINEAR DIRAC EQUATION IN 1+1 DIMENSIONS 预览
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作者 张永前 赵勤 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第2期597-606,共10页
This paper studies the large time behavior of solution for a class of nonlinear massless Dirac equations in R1+1. It is shown that the solution will tend to travelling wave solution when time tends to infinity.
关键词 large time behavior NONLINEAR DIRAC EQUATION gross-Neveu model global STRONG SOLUTION gravelling wave SOLUTION
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非线性随机结构自由振动的数值分析 预览
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作者 胡晓君 《建材世界》 2019年第2期61-63,共3页
目前关于非线性随机结构体系的系统性的分析研究方法还很少。提出的基于Newmark-β格式的混合摄动伽辽金法就是对非线性随机结构系统动力响应分析研究的一个新的尝试。以带阻尼Duffing方程自由振动为例,介绍了该方法在非线性随机结构动... 目前关于非线性随机结构体系的系统性的分析研究方法还很少。提出的基于Newmark-β格式的混合摄动伽辽金法就是对非线性随机结构系统动力响应分析研究的一个新的尝试。以带阻尼Duffing方程自由振动为例,介绍了该方法在非线性随机结构动力学领域的应用。与传统摄动法作对比结果更好。 展开更多
关键词 非线性 随机 DUFFING方程
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开关磁阻电机矩角特性模型非线性拟合方法
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作者 叶威 马齐爽 +1 位作者 徐萍 张珀铭 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2019年第1期83-92,共10页
开关磁阻电机难以采用传统电机分析方法进行建模,通过分析开关磁阻电机电磁转矩生成原理,确定了不同电机饱和状态下电磁转矩与相电感导数之间的关系。用分段函数非线性拟合的方式对电感导数曲线进行建模,再进一步得到开关磁阻电机可逆... 开关磁阻电机难以采用传统电机分析方法进行建模,通过分析开关磁阻电机电磁转矩生成原理,确定了不同电机饱和状态下电磁转矩与相电感导数之间的关系。用分段函数非线性拟合的方式对电感导数曲线进行建模,再进一步得到开关磁阻电机可逆矩角特性的解析模型,并基于电机的结构参数和约束条件逐一确定和优化了模型的各个参数。利用可逆矩角特性模型,可以方便地计算电机磁化曲线和瞬时磁链,给电机设计及驱动控制带来很大的方便。通过2个样机的实测数据和有限元结果对该模型解析计算结果的准确性进行了验证。 展开更多
关键词 开关磁阻电机 建模 非线性 矩角特性 曲线拟合
基于鸟群算法优化的桥式吊车线性自抗扰控制 预览
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作者 唐超 刘惠康 +1 位作者 曹宇轩 柴琳 《高技术通讯》 CAS 北大核心 2019年第4期371-378,共8页
针对欠驱动吊车的防摆与定位问题,本文提出一种基于线性自抗扰控制技术(LADRC)的欠驱动桥式吊车控制策略及控制器参数优化方法。区别于其他常规的桥式吊车控制策略,该方法不需要对吊车模型进行任何近似解耦或线性化处理,允许模型存在一... 针对欠驱动吊车的防摆与定位问题,本文提出一种基于线性自抗扰控制技术(LADRC)的欠驱动桥式吊车控制策略及控制器参数优化方法。区别于其他常规的桥式吊车控制策略,该方法不需要对吊车模型进行任何近似解耦或线性化处理,允许模型存在一定的不确定性并且考虑了系统所受的摩擦力与空气阻力等干扰,同时针对传感器噪声污染环境下控制器的参数整定问题,应用鸟群优化算法进行参数优化。在负载质量和吊绳绳长等发生变化或存在不确定因素的情况下,控制策略依然能实现对台车的精确定位与负载摆动的有效抑制。最后通过仿真证明了控制方法具有良好的控制性能。 展开更多
关键词 桥式吊车 非线性 防摆与定位 线性自抗扰控制 鸟群算法(BSA) 参数优化
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BLOW-UP OF SOLUTION FOR A VISCOELASTIC WAVE EQUATION WITH DELAY 预览
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作者 吴舜堂 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第1期329-338,共10页
In this paper, we consider the following viscoelastic wave equation with delay|ut|ρutt-△u-△utt+∫0t g(t-8)△u(8)d8 + μ1 ut(x,t) + μ2 ut(x,t-τ) = b|u|p-2 u in a bounded domain. Under appropriate conditions on μ... In this paper, we consider the following viscoelastic wave equation with delay|ut|ρutt-△u-△utt+∫0t g(t-8)△u(8)d8 + μ1 ut(x,t) + μ2 ut(x,t-τ) = b|u|p-2 u in a bounded domain. Under appropriate conditions on μ1, μ2, the kernel function g, the nonlinear source and the initial data, there are solutions that blow up in finite time. 展开更多
关键词 BLOW up nonlinear SOURCE WAVE EQUATION DELAY VISCOELASTIC
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一种非线性模型下的复合材料螺栓连接失效分析 预览
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作者 李沛城 常楠 +1 位作者 赵美英 黄河源 《航空工程进展》 CSCD 2019年第2期171-178,共8页
复合材料螺栓连接结构已广泛应用于飞机结构件,研究其拉伸失效问题具有重要意义。结合Hashin失效准则、能量耗散率方法、Puck失效准则和材料损伤连续退化方法,建立一种包含面内损伤和层间损伤的复合材料三维非线性模型;将含开孔层合板... 复合材料螺栓连接结构已广泛应用于飞机结构件,研究其拉伸失效问题具有重要意义。结合Hashin失效准则、能量耗散率方法、Puck失效准则和材料损伤连续退化方法,建立一种包含面内损伤和层间损伤的复合材料三维非线性模型;将含开孔层合板准静态拉伸试验结果与有限元数值模拟结果进行对比,两者之间的应力应变响应及最终断裂失效模式一致,证明该本构模型是有效的;在此基础上,对复合材料单钉双搭接螺栓连接结构进行拉伸失效分析。结果表明:数值模拟所得位移载荷响应与试验结果吻合良好,极限拉伸载荷误差不超过5%,满足工程应用要求;加载过程中的孔边变形和损伤累积使得螺栓连接结构整体刚度下降,其最终破坏模式为中搭接板挤压失效。 展开更多
关键词 复合材料 非线性 开孔板 螺栓连接 失效准则 连续损伤退化
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Decomposition Based Fuzzy Model Predictive Control Approaches for Interconnpcted Nonlinear Systems
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作者 Latifa Dalhoumi Mohamed Chtourou Mohamed Djemel 《国际自动化与计算杂志:英文版》 EI CSCD 2019年第3期369-388,共20页
This paper proposes fuzzy model predictive control(FMPC)strategies for nonlinear interconnected systems based mainly on a system decomposition approach.First,the Takagi-Sugeno(TS)fuzzy model is formulated in such a wa... This paper proposes fuzzy model predictive control(FMPC)strategies for nonlinear interconnected systems based mainly on a system decomposition approach.First,the Takagi-Sugeno(TS)fuzzy model is formulated in such a way to describe the behavior of the nonlinear system.Based on that description,a fuzzy model predictive control is determined.The system under consideration is decomposed into several subsystems.For each subsystem,the main idea consists of the decomposition of the control action into two parts:The decentralized part contains the parameters of the subsystem and the centralized part contains the elements of other subsystems.According to such decomposition,two strategies are defined aiming to circumvent the problems caused by interconnection bet ween subsystems.The feasibility and efficiency of the proposed method are illustrated through numerical examples. 展开更多
关键词 MODEL PREDICTIVE CONTROL centralized CONTROL decentralized CONTROL Takagi-Sugeno(TS)fuzzy models·interconnected nonlinear systems FUZZY MODEL PREDICTIVE CONTROL parallel distributed compensation
COUPLED NONLOCAL NONLINEAR SCHR?DINGER EQUATION AND N-SOLITON SOLUTION FORMULA WITH DARBOUX TRANSFORMATION
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作者 Rui Fan Fajun Yu 《应用数学年刊:英文版》 2019年第1期47-62,共16页
Ablowitz and Musslimani proposed some new nonlocal nonlinear integrable equations including the nonlocal integrable nonlinear Schr?dinger equation. In this paper, we investigate the Darboux transformation of coupled n... Ablowitz and Musslimani proposed some new nonlocal nonlinear integrable equations including the nonlocal integrable nonlinear Schr?dinger equation. In this paper, we investigate the Darboux transformation of coupled nonlocal nonlinear Schr?dinger(CNNLS) equation with a spectral problem. Starting from a special Lax pairs, the CNNLS equation is constructed. Then, we obtain the one-, two-and N-soliton solution formulas of the CNNLS equation with N-fold Darboux transformation. Based on the obtained solutions, the propagation and interaction structures of these multi-solitons are shown, the evolution structures of the one-dark and one-bright solitons are exhibited with N = 1,and the overtaking elastic interactions among the two-dark and two-bright solitons are considered with N = 2. The obtained results are different from those of the solutions of the local nonlinear equations. Some different propagation phenomena can also be produced through manipulating multi-soliton waves.The results in this paper might be helpful for understanding some physical phenomena described in plasmas. 展开更多
关键词 COUPLED NONLOCAL NONLINEAR Schr?dinger(CNNLS) EQUATION DARBOUX transformation dark SOLITON bright SOLITON
Determination of the Backward Predictability Limit and Its Relationship with the Forward Predictability Limit 预览
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作者 Xuan LI Ruiqiang DING Jianping LI 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第6期669-677,共9页
In this work, two types of predictability are proposed-forward and backward predictability-and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively estim... In this work, two types of predictability are proposed-forward and backward predictability-and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively estimate the local forward and backward predictability limits of states in phase space. The forward predictability mainly focuses on the forward evolution of initial errors superposed on the initial state over time, while the backward predictability is mainly concerned with when the given state can be predicted before this state happens. From the results, there is a negative correlation between the local forward and backward predictability limits. That is, the forward predictability limits are higher when the backward predictability limits are lower, and vice versa. We also find that the sum of forward and backward predictability limits of each state tends to fluctuate around the average value of sums of the forward and backward predictability limits of sufficient states.Furthermore, the average value is constant when the states are sufficient. For different chaotic systems, the average value is dependent on the chaotic systems and more complex chaotic systems get a lower average value. For a single chaotic system,the average value depends on the magnitude of initial perturbations. The average values decrease as the magnitudes of initial perturbations increase. 展开更多
关键词 nonlinear local Lyapunov EXPONENT FORWARD and BACKWARD PREDICTABILITY LIMIT negative correlation AVERAGE value
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碳纤维/石墨烯导电沥青混凝土的非线性伏安特性 预览
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作者 谭忆秋 刘凯 王英园 《建筑材料学报》 EI CAS CSCD 北大核心 2019年第2期278-283,共6页
基于实验室制备的碳纤维/石墨烯导电沥青胶浆及沥青混凝土,研究了碳纤维/石墨烯导电沥青混凝土的导电特性与导电行为,以及电阻与外加电压间的相关性.结果表明:所制备的沥青胶浆及沥青混凝土均表现出了明显的非线性导电行为,其电阻率随... 基于实验室制备的碳纤维/石墨烯导电沥青胶浆及沥青混凝土,研究了碳纤维/石墨烯导电沥青混凝土的导电特性与导电行为,以及电阻与外加电压间的相关性.结果表明:所制备的沥青胶浆及沥青混凝土均表现出了明显的非线性导电行为,其电阻率随着电压的增大显著降低,并且非线性程度随着导电填料掺量的增大逐渐减弱.运用动态随机电阻器网络模型证明了隧道效应是造成这一非线性导电行为的主要原因,在足够强的电压作用下,原本处于绝缘状态下的部分载流子有序排列,出现了额外的导电通路. 展开更多
关键词 碳纤维 石墨烯 导电沥青混凝土 非线性 伏安特性 隧道效应
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Quantum electrodynamics experiments with colliding petawatt laser pulses
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作者 I.C.E.Turcu B.Shen +8 位作者 D.Neely G.Sarri K.A.Tanaka P.McKenna S.P.D.Mangles T.-P.Yu W.Luo X.-L.Zhu Y.Yin 《高功率激光科学与工程:英文版》 CAS CSCD 2019年第1期74-81,共8页
A new generation of high power laser facilities will provide laser pulses with extremely high powers of 10 petawatt(PW)and even 100 PW,capable of reaching intensities of 10^23 W/cm^2 in the laser focus.These ultra-hig... A new generation of high power laser facilities will provide laser pulses with extremely high powers of 10 petawatt(PW)and even 100 PW,capable of reaching intensities of 10^23 W/cm^2 in the laser focus.These ultra-high intensities are nevertheless lower than the Schwinger intensity Is=2.3×10^29 W/cm^2 at which the theory of quantum electrodynamics(QED)predicts that a large part of the energy of the laser photons will be transformed to hard Gamma-ray photons and even to matter,via electron-positron pair production.To enable the investigation of this physics at the intensities achievable with the next generation of high power laser facilities,an approach involving the interaction of two colliding PW laser pulses is being adopted.Theoretical simulations predict strong QED effects with colliding laser pulses of≥10 PW focused to intensities≥10^22 W/cm^2. 展开更多
关键词 colliding PETAWATT LASER pulses electron-positron pairs creation nonlinear Breit-Wheeler process PETAWATT LASER facilities quantum ELECTRODYNAMICS
High efficiency second harmonic generation of nanojoule-level femtosecond pulses in the visible based on BiBO
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作者 Mario Galletti Hugo Pires +4 位作者 Victor Hariton Celso Paiva Joao Swen Künzel Marco Galimberti Goncalo Figueira 《高功率激光科学与工程:英文版》 CAS CSCD 2019年第1期82-89,共8页
We demonstrate high efficiency second harmonic generation(SHG)of near infrared femtosecond pulses using a BiB3O6 crystal in a single-pass tight focusing geometry setup.A frequency doubling efficiency of 63%is achieved... We demonstrate high efficiency second harmonic generation(SHG)of near infrared femtosecond pulses using a BiB3O6 crystal in a single-pass tight focusing geometry setup.A frequency doubling efficiency of 63%is achieved,which is,to the best of our knowledge,the highest value ever reported in the femtosecond regime for such low energy(nJ-level)pumping pulses.Theoretical analyses of the pumping scheme focusing waist and the SHG efficiency are performed,by numerically solving the three wave mixing coupled equations in the plane-wave scenario and by running simulations with a commercial full 3D code.Simulations show a good agreement with the experimental data regarding both the efficiency and the pulse spectral profile.The simulated SHG pulse temporal profile presents the characteristic features of the group velocity mismatch broadening in a‘thick’crystal. 展开更多
关键词 nonlinear process SECOND HARMONIC generation PUMPING scheme PARAMETRIC amplification/oscillators high power laser
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