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61.
Dendrite to symmetry-broken dendrite transition in directional solidification of non-axially oriented crystals
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In this paper, the morphological transition from dendrite to symmetry-broken dendrite is investigated in the directional ;olidification of non-axially-oriented crystals using a quantitative phase-field model. The effects of pulling velocity and zrystal orientation on the morphological transition are investigated. The results indicate the orientation dependence of the ;ymmetry-broken double dendrites. A dendrite to symmetry-broken dendrite transition is found by varying the pulling telocity at different crystal orientations and the symmetry-broken multiple dendrites emerge as a transition state for the ;ymmetry-broken double dendrites. The state region during the transition can be well characterized through the variations ff the characteristic angle and the average primary dendritic spacing. 相似文献
62.
扰动的存在使得系统标准输出规律变成非标准输出规律的现象等价于在扰动存在的条件下,非标准输出规律被挖掘-发现;利用函数P-集合模型与它的动态特征给出这个现象的理论研究.主要结果:给出函数P-集合的结构与规律扰动,扰动恢复概念;给出扰动度量;利用这些概念,给出内扰动与属性合取扩展定理;属性合取扩展与内扰动规律挖掘定理,内扰动与规律挖掘辨识定理,内扰动与规律挖掘属性不变性定理. 相似文献
63.
《Optimization》2012,61(1):103-120
Find a connection of two points in the plane with minimal cost, the cost per length unit depending on the location, and the curvature of the curve being limited. For simple cases, as a necessary condition, the known optical law of refraction is supplemented by a “circular law of refraction”. For the general case, a practicable numerical procedure is developed on the foundation of graph theory. This procedure is able to additionally take into consideration the given directions of the curve in the end points. Several examples demonstrate fundamental solution structures for classical basic problems and also solutions for routing problems in planning traffic ways. 相似文献
64.
T. C. Lubensky 《Pramana》2005,64(5):727-742
This paper reviews the derivation of equations for slow dynamical processes in a variety of systems, including rotating rigid
rotors, crystalline solids, isotropic and nematic elastomers, gels in an isotropic fluid background, and nematic liquid crystals.
It presents a recent derivation of the Leslie-Ericksen equations for the dynamics of nematic liquid crystals that clarifies
the nature of the nonhydrodynamic modes in these equations. As a final example of the phenomenological approach to slow dynamical
processes, it discusses the dynamics of a driven nonequilibrium system: a two-dimensional gas of chiral ‘rattlebacks’ on a
vibrating substrate. 相似文献
65.
66.
This paper presents a numerical method that couples the incompressible Navier–Stokes equations with the level set method in a curvilinear co‐ordinate system for study of free surface flows. The finite volume method is used to discretize the governing equations on a non‐staggered grid with a four‐step fractional step method. The free surface flow problem is converted into a two‐phase flow system on a fixed grid in which the free surface is implicitly captured by the zero level set. We compare different numerical schemes for advection of the level set function in a generalized curvilinear format, including the third order quadratic upwind interpolation for convective kinematics (QUICK) scheme, and the second and third order essentially non‐oscillatory (ENO) schemes. The level set equations of evolution and reinitialization are validated with benchmark cases, e.g. a stationary circle, a rotating slotted disk and stretching of a circular fluid element. The coupled system is then applied to a travelling solitary wave, and two‐ and three‐dimensional dam breaking problems. Some interesting free surface phenomena are revealed by the computational results, such as, the large free surface vortices, air entrapment and splashing of the water surge front. The computational results are in excellent agreement with theoretical predictions and experimental data, where they are available. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
67.
用普通物理和原子物理的语言论述了对称性破缺机制和理论模型,介绍了2008年度诺贝尔物理学获奖者小林诚(Makoto Kobayashi)、益川敏英(Toshihide Maskawa)关于弱相互作用的理论模型(KM模型)和对称性破缺的起源,它是对电弱统一理论的完美补充;详细分析了在微观粒子世界系列实验中对称性自发破缺和夸克的发现. 相似文献
68.
The magnetic moments ofb-quark baryons within the framework of five quark models are derived. Also the transition magnetic moments of variousb-quark baryons are calculated. 相似文献
69.
In this note we introduce a process, which we call 'the Poisson broken lines process", and we compute the intensity of a point process which is obtained by intersecting the Poisson broken lines process with an abscissa axis. In the second part we apply this result to compute an explicit lower bound for the time constant of a planar Bernoulli first passage percolation model with the parameter p < pc. 相似文献
70.
We propose a new Kaluza-Klein-like scheme based on a five-dimensional Riemannian space in which energy plays the role of the fifth dimension and spacetime is deformed. The solutions of the five-dimensional Einstein equations in vacuum allow us to recover, as special cases, the energy-dependent phenomenological metrics, describing the four fundamental interactions, recently derived from the analysis of some experimental data. 相似文献