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   41篇
  免费   0篇
化学   2篇
力学   4篇
数学   13篇
物理学   22篇
  2021年   1篇
  2017年   1篇
  2013年   1篇
  2012年   5篇
  2011年   4篇
  2010年   4篇
  2009年   3篇
  2008年   1篇
  2007年   3篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2001年   1篇
  1999年   2篇
  1994年   4篇
  1992年   1篇
  1982年   1篇
  1980年   2篇
  1979年   1篇
  1974年   2篇
排序方式: 共有41条查询结果,搜索用时 46 毫秒
1.
An initial boundary value problem for the dynamic system of anisotropic elasticity in a half space is studied in the paper. A novel method of finding an exact solution of this problem for a special polynomial form of initial data and inhomogeneous term of the system is described. On the base of this method the simulation of elastic waves in different homogeneous anisotropic half spaces is implemented.  相似文献   
2.
Encoding algorithms for constructing scanning trajectories of attention points in a complex image have been developed. Image fragments can be extracted and classified by using neuron-like media as well. The algorithms that we propose have been implemented in a program unit intended for use in more complicated hierarchical systems of pattern recognition.Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 9, pp. 1183–1194, September, 1994.  相似文献   
3.
4.
A general algorithm is presented for transforming the exact solutions of the system of plane ideal plasticity of the Mises medium by using the superposition principle for solutions which arises as a corollary of the fact that the original system admits an infinite-dimensional symmetry group. As an example, there is considered the relation between the known exact solutions: the Prandtl solution for a thin layer compressed by rough solid plates and the Nadai solution for the radial distribution of stresses in a convergent channel in the shape of a flat wedge.  相似文献   
5.
The instant coffee model has been taken to study self-sustained oscillations in liquid dispersive media using dynamic self-organization processes in drying droplets that stay sessile on a solid wetted substrate. The width of the formed ring and the dynamics of mechanical properties of the drying sediment and the way they fluctuated over 11 h of the experiment have been measured. Analysis has shown a high degree of correlation between these indicators. This dynamics reflects processes that develop in the examined liquid medium. The possible mechanism of self-sustained oscillations, which is related to the aggregation–disaggregation of the colloidal phase and fluctuations of the interphase tension, has been discussed. The practical significance of this work is that fluctuation processes in liquid dispersive media need to be taken into account as a natural source of systematic measurement error.  相似文献   
6.
A series of anthraquinone (C(14)O(2)H(8)) derivatives has been studied by means of electron capture negative ion mass spectrometry (ECNI-MS), photoelectron spectroscopy (PES), and AM1 quantum chemical calculations. Mean lifetimes of molecular negative ions M(-.) (MNI) have been measured. The mechanism of long-lived MNI formation in the epithermal energy region of incident electrons has been investigated. A simple model of a molecule (a spherical potential well with the repulsive centrifugal term) has been applied for the analysis of the energy dependence of cross sections at the first stage of the electron capture process. It has been shown that a temporary resonance of MNI at the energy approximately 0.5 eV corresponds to a shape resonance with lifetime 1-2.10(-13) s in the f-partial wave (l = 3) of the incident electron. The next resonant state of MNI at the energy approximately 1.7 eV has been associated with the electron excited Feshbach resonance (whose parent state is a triplet npi* transition). In all cases the initial electron state of the MNI relaxes into the ground state by means of a radiationless transition, and the final state of the MNI is a nuclear excited resonance with a lifetime measurable on the mass spectrometry timescale. Copyright 1999 John Wiley & Sons, Ltd.  相似文献   
7.
Base models of homogeneous neuron-like media and the corresponding systems of spatiotemporal solutions are considered. Ways of using these models and solutions as the base models for designing hierarchic systems of parallel processing of complex information flows with the help of neuron-like algorithms are studied. The version of a decision-making system with tunable architecture at a coarsegrain level (for adapting the system to the processing purposes and type of image) and universal neuron-like subsystems at a fine-grain level (for providing a wide variety of operations needed to extract local and global features and to encode individual fragments or the whole of the image) is developed. Examples of the transformation processes in the images of biological objects (growing neurons, erythrocytes, fingerprints) in a hierarchic decision-making system are demonstrated.Institute of Applied Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 8, pp. 961–986, August, 1994.  相似文献   
8.
How do living systems process information? The search for an answer to this question is ongoing. We have developed an intelligent video analytics system. The process of the formation of detectors for content-based image retrieval aimed at detecting objects of various types simulates the operation of the structural and functional modules for image processing in living systems. The process of detector construction is, in fact, a model of the formation (or activation) of connections in the cortical column (structural and functional unit of information processing in the human and animal brain). The process of content-based image retrieval, that is, the detection of various types of images in the developed system, reproduces the process of “triggering” a model biomorphic column, i.e., a detector in which connections are formed during the learning process. The recognition process is a reaction of the receptive field of the column to the activation by a given signal. Since the learning process of the detector can be visualized, it is possible to see how a column (a detector of specific stimuli) is formed: a face, a digit, a number, etc. The created artificial cognitive system is a biomorphic model of the recognition column of living systems.  相似文献   
9.
Electrospray ionization (ESI) combined with multiple-stage tandem mass spectrometry (MS(n)) was used to directly analyze the glycolipid mixture from bacteria Bacillus pumilus without preliminary separation. Full scan ESI-MS revealed the composition of picomole quantities of glycerolglycolipid species containing C(14)-C(19) fatty acids, some of which were monounsaturated. Two main components were identified from their molecular masses and fragmentation pathways. The fragmentation pathway of the known compound compared with the investigated compound verified the proposed structure as 1(3)-acyl-2-pentadecanoyl-3(1)-O-[beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl]-sn-glycerols. A comparison of the multiple tandem mass spectra of the different alkali-metal cation adducts indicates that the intensity of fragments and the dissociation pathways are dependent on the alkali-metal type. The basic structures of glycerolglycolipids were reflected clearly from the fragmentation patterns of the sodium cations. The intense fragments of the sugar residue from the precursor ions were obtained from the lithiated adduct ions. ESI-MS(n) spectra of [M + K](+) ions did not provide as much fragmentation as [M + Na](+) and [M + Li](+) adducts, but their spectra allow the position of glycerol acylation to be determined. On the basis of MS(2) spectra of [M + K](+) ions, it was established that all components have a C(15:0) fatty acid at the sn-2 position of the glycerol backbone and C(14)-C(19) acids at the sn-1 position of the glycerol backbone. Copyright 1999 John Wiley & Sons, Ltd.  相似文献   
10.
Qualitative analysis of experimental data for the mechanisms of structuring in drying drops of biological fluids is carried out. It is shown that the structural evolution of the drying drops is a complex process in which two stages can be separated out by convention: events occurring during evaporation of free water and structuring due to evaporation of film water. Consideration of the structural evolution of drying drops on the basis of the physical chemistry of solutions, physics of polymers, mechanics, and materials science makes it possible to explain the phenomenology of the process in terms of well-known physical phenomena.  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