首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   71篇
  免费   3篇
化学   21篇
力学   3篇
数学   39篇
物理学   11篇
  2019年   1篇
  2017年   1篇
  2016年   5篇
  2015年   2篇
  2014年   1篇
  2013年   10篇
  2012年   14篇
  2011年   8篇
  2010年   4篇
  2009年   5篇
  2008年   6篇
  2007年   3篇
  2006年   2篇
  2005年   4篇
  2004年   3篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
排序方式: 共有74条查询结果,搜索用时 15 毫秒
61.
We address electrostatic charging of unstrained and strained latex rubber sheets contacted with a series of materials: polytetrafluoroethylene (PTFE), polyurethane (PU) and stainless steel (SS). For PTFE, strain causes a reversal in the direction of charge transfer. For PU, the direction of charge transfer is reversed after repeated contacts due to material transfer, and strain increases the number of contacts needed for this reversal. For SS, strain reduces the frequency of electrical discharges occurring. These effects may be explained by strain either changing material properties relevant to triboelectric charging, or changing the nature of contact between the surfaces.  相似文献   
62.
63.
64.
In this work, we study the existence and uniqueness of mild solutions for stochastic partial integrodifferential equations under local non‐Lipschitz conditions on the coefficients. Our analysis makes use of the theory of resolvent operators as developed by R. Grimmer as well as a stopping time technique. Our results complement and improve several earlier related works. An example is provided to illustrate the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
65.
In this paper, we study the well‐posedness and exact controllability of a physical model for an extrusion process in the isothermal case. The model expresses the mass balance in the extruder chamber and consists of a hyperbolic partial differential equation (PDE) and a nonlinear ordinary differential equation (ODE) whose dynamics describes the evolution of a moving interface. By suitable change of coordinates and fixed point arguments, we prove the existence, uniqueness, and regularity of the solution and finally, the exact controllability of the coupled system. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
66.
In this paper, we look at the influence of the choice of the Reynolds tensor on the derivation of some multiphasic incompressible fluid models, called Kazhikhov–Smagulov type models. We show that a compatibility condition between the viscous tensor and the diffusive term allows us to obtain similar models without assuming a small diffusive term as it was done for instance by A. Kazhikhov and Sh. Smagulov. We begin with two examples: The first one concerning pollution and the last one concerning a model of combustion at low Mach number. We give the compatibility condition that provides a class of models of the Kazhikhov–Smagulov type. We prove that these models are globally well posed without assumptions between the density and the diffusion terms.  相似文献   
67.
Cleavage reactions of 2,3-diamino-meso-tetraarylporphyrins and meso-tetraarylporphyrins fused to imidazole rings afforded secochlorins including stable free base derivatives.  相似文献   
68.
In this paper we provide a detailed investigation of the problem of existence of solutions to the stochastic magnetohydrodynamic equations which describe the motion of turbulent particles of fluids in a magnetic field. The results are proved through a delicate combination of Galerkin approximation scheme with some deep compactness results of analytic and probabilistic nature.  相似文献   
69.
Elliott JT  Diop M  Lee TY  Lawrence KS 《Optics letters》2012,37(13):2571-2573
Optical dye-dilution techniques can quantify kinetic parameters in a region of tissue, but currently rely on a two-step process-spatial reconstruction of the dye concentration, repeated at every time-point, and subsequent kinetic analysis of the time-dependent change in dye concentration. Inaccuracies, in this approach, are due mainly to the ill-posed nature of the spatial reconstruction problem, which propagates into kinetic analysis and result in errors in extracted dynamic parameters. We present a hybrid kinetic deconvolution optical reconstruction algorithm, effectively combining optical reconstruction and model-independent kinetic analysis into a single inverse problem that is better posed. Kinetic parameters of multiple tissue regions can be quantified simultaneously. As proof of principle, we provide numerical experiments in reflectance-based and fluorescence molecular tomography scenarios.  相似文献   
70.
A multiple linear correlation is done between atmospheric transmissivity for four biologically active radiation daily doses (UVB, erythemal, DNA and plant damage) T, and three parameters (daily sunshine fraction σ, cosine of the daily minimum solar zenith angle μmin and daily total ozone column Ω). T is defined as the ratio of a daily dose to its extra‐atmospheric value. The data used are spectral UV measurements (390–400 nm at 0.5 nm step) recorded along year 2000 and over 8 months of year 2001 at Briançon Station (Alps, 1300 m above sea level) that forms part of the French UV network. The coefficients obtained from year 2000 correlation permit to retrieve daily doses for year 2001 with an average error running from 3 to 9% for monthly mean values and from 2 to 4.5% for 3‐monthly mean values, depending on daily dose type. The retrieval of yearly mean value gives an error between 4 and 7.5%. Retrieving the daily dose of a given day, where σ≥ 0.2, introduces error running from 16 to 32% depending on daily dose. An attempt to retrieve the yearly mean UVB daily dose for a northern France site, from the previous coefficients, gives encouraging results.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号