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排序方式: 共有211条查询结果,搜索用时 9 毫秒
101.
The paper presents a new study on a tri-layer thin plate.Shadow moiré implemented with an advanced phase unwrapping technique is employed to obtain actual flexural deformation of a real-life plate sample subjected to thermal loads.An analytical model is re-formulated to provide the plate with global closed-form solutions of the plate deflection as well as the interfacial stress and strain.With the measurements and the solutions available,an inverse iterative approach is developed to evaluate and maximize th... 相似文献
102.
This article deals with an analytical mechanical model of reinforced concrete damaged by steels corrosion. It is based on the taking into account of local bond between steel and the tensile concrete located between the cracks. Then, this model allows to quantify the coupled effect of steel cross section reduction and loss of bond strength due to steel corrosion on mechanical behaviour of reinforced concrete. To cite this article: A. Castel et al., C. R. Mecanique 330 (2002) 45–50 相似文献
103.
本文的目的是讨论补偿Lévy流的实践稳定性问题.我们推广了一些微分不等式,并通过Lyapunov函数与比较原理,得到补偿Lévy流的实践稳定性的若干判据. 相似文献
104.
Yong LIU Jianglun WU Fengxia YANG Jianliang ZHAI 《Frontiers of Mathematics in China》2011,6(6):1147-1183
In this paper, we study an ergodic theorem of a parabolic Andersen model driven by Lévy noise. Under the assumption that A = (a(i, j))
i,j∈S
is symmetric with respect to a σ-finite measure gp, we obtain the long-time convergence to an invariant probability measure ν
h
starting from a bounded nonnegative A-harmonic function h based on self-duality property. Furthermore, under some mild conditions, we obtain the one to one correspondence between
the bounded nonnegative A-harmonic functions and the extremal invariant probability measures with finite second moment of the nonnegative solution
of the parabolic Anderson model driven by Lévy noise, which is an extension of the result of Y. Liu and F. X. Yang. 相似文献
105.
AN IMPROVED NONLINEAR CLOSED GRAPH THEOREM 总被引:1,自引:0,他引:1
References: 《高校应用数学学报(英文版)》2007,22(2):226-228
In this paper, a new nonlinear closed graph theorem is established, whose result improves substantially a recent-known important conclusion. 相似文献
106.
铁的氢氧化合物稳定相针铁矿(α-FeOOH)及四方纤铁矿(β-FeOOH)的合成材料因具有纳米颗粒粒径、较高比表面积,在工业生产和环境治理中被广泛应用。α,β-FeOOH作为重金属等污染物的吸附材料尤受关注。但其合成过程中溶液pH值和反应条件(如不同温度下加热或室温磁力搅拌等)对α,β-FeOOH矿物材料晶型、颗粒形貌、尺寸和界面特性的影响及其与矿物环境功能的相关性报道较少。故本工作基于Fe(NO3)3和FeCl3溶液在一定pH值范围内分别易于形成α-FeOOH和β-FeOOH稳定相,利用X射线衍射仪、透射/扫描电子显微镜和激光粒度分析仪对加热(40和70 ℃)和磁力搅拌(25 ℃)条件下形成的矿物α, β-FeOOH的晶型和颗粒形貌结构进行了鉴定与表征,同时利用红外光谱仪测定了矿物表面的特征结构基团。研究结果表明,40和70 ℃反应温度下形成的矿物Aka-T40, Aka-T70, Gth-T70具有颗粒均一、结晶型较好、比表面积较大等特性,是良好的去除环境污染物的吸附剂材料。 相似文献
107.
通过对光纤法布里-珀罗(Fabry-Perot cavity,F-P)腔单波长功率监测,对时域信号进行快速傅里叶变换(FFT),检测振动信号频率.建立了F-P腔的瞬时响应模型.发现透射响应比反射响应有微小延时,证明了F-P腔的多次反射原理对于一般频率不超过几十千赫兹的振动信号的测量没有影响.直接作用在F-P腔上的振动较强时,超过解调单值范围,波形发生畸变.通过增大振动源与F-P腔的距离控制解调单值性,当距离增至8 cm时,获得相对准确的解调结果. 相似文献
108.
The physical nature of the auroral electron acceleration has been an
outstanding problem in space physics for decades. Some recent observations
from the auroral orbit satellites, FREJA and FAST, showed that large
amplitude solitary kinetic Alfvén waves (SKAWs) are a common electromagnetic active phenomenon in the auroral magnetosphere. In a low-β (i.e., β/2<<me/mi<<1) plasma, the drift velocity of electrons relative to ions within SKAWs is much larger than thermal velocities of both electrons and ions. This leads to instabilities and causes dissipations of SKAWs. In the present work, based on the analogy of classical particle motion in a potential well, it is shown that a shock-like structure can be formed from SKAWs if dissipation effects are included. The reformed SKAWs with a shock-like structure have a local density jump and a net field-aligned electric potential drop of order of mevA2/e over a characteristic width
of several λe. As a consequence, the reformed SKAWs can efficiently accelerate electrons field-aligned to the order of the local
Alfvén velocity. In particular, we argue that this electron acceleration mechanism by reformed SKAWs can play an important role in the auroral electron
acceleration problem. The result shows that not only the location of
acceleration regions predicted by this model is well consistent with the
observed auroral electron acceleration region of 1—2 RE above the auroral ionosphere, but also the accelerated electrons from this region can obtain an energy of several keV and carry a field-aligned current of several
μA/m2 which are comparable
to the observations of auroral electrons. 相似文献
109.
在复杂背景中,往往难以实现目标的自动检测,依据Wigner-Ville分布能够对图像在空间域/空间频率域上联合表示的特性.研究了图像经伪Wigner-Ville分布后Rnyi熵的统计特性,分析了人造目标的出现会引起自然场景中Rnyi熵统计特性的变化,并在此基础上提出了一种新的基于伪Wigner-Ville分布和Rnyi熵的显著图生成方法.之后对显著图进行简便的阈值分割,完成目标检测.实验结果表明,所提出的方法能够有效地检测复杂地面背景中的军用车辆. 相似文献
110.