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91.
A. Bershadskii E. Dremencov D. Fukayama G. Yadid 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(4):581-585
Nonlinear statistical properties of Ventral Tegmental Area (VTA) of limbic brain are studied in vivo. VTA plays key role in generation of pleasure and in development of psychological drug addiction. It is shown that spiking
time-series of the VTA dopaminergic neurons exhibit long-range correlations with self-averaging behavior. This specific VTA
phenomenon has no relation to VTA rewarding function. Last result reveals complex role of VTA in limbic brain.
Received 17 April 2002 / Received in final form 30 September 2002 Published online 31 December 2002 相似文献
92.
Local structure theory calculations7 are applied to the study of cellular automata on the two-dimensional hexagonal lattice. A particular hexagonal lattice rule denoted (3422) is considered in detail. This rule has many features in common with Conway'sLife. The local structure theory captures many of the statistical properties of this rule; this supports hypotheses raised by a study ofLife itself(6). As inLife, the state of a cell under (3422) depends only on the state of the cell itself and the sum of states in its neighborhood at the previous time step. This property implies that evolution rules which operate in the same way can be studied on different lattices. The differences between the behavior of these rules on different lattices are dramatic. The mean field theory cannot reflect these differences. However, a generalization of the mean field theory, the local structure theory, does account for the rule-lattice interaction. 相似文献
93.
We apply ideas from commutative algebra, and Morita theory to algebraic topology using ring spectra. This allows us to prove new duality results in algebra and topology, and to view (1) Poincaré duality for manifolds, (2) Gorenstein duality for commutative rings, (3) Benson–Carlson duality for cohomology rings of finite groups, (4) Poincaré duality for groups and (5) Gross–Hopkins duality in chromatic stable homotopy theory as examples of a single phenomenon. 相似文献
94.
The boundaries between the three phases of the Domany-Kinzel probabilistic cellular automaton are determined with high accuracy via the gradient method. The difficulties the extrapolation to the thermodynamic limit are circumvented and the critical exponents are also presented. 相似文献
95.
Detonation propagation behavior associated with sudden expansions has been investigated both experimentally and numerically.
Different mechanisms, from sustained propagation to detonation failure and reinitiation including shock and flame front decoupling
and recoupling have been observed with the schlieren technique. The shock-induced flame propagation has been modeled with
two-step chemistry and structured two-dimensional CFD on arbitrary geometries. The results of the numerical simulations show
good correspondence to the variety of phenomena observed in experiments. Thus the numerical simulation can be used to study
detonation propagation in complex geometries. It provides a tool for the design of safety devices and aids experimental investigations.
Received 4 August 1995 / Accepted 25 April 1996 相似文献
96.
All metallic, hollow sandwich cylinders having ultralight two-dimensional (2D) prismatic cores are optimally designed for maximum thermo-mechanical performance at minimum mass. The heated cylinder is subjected to uniform internal pressure and actively cooled by forced air convection. The use of two different core topologies is exploited: square- and triangular-celled cores. The minimum mass design model is so defined that three failure modes are prevented: facesheet yielding, core member yielding, and core member buckling. The intersection-of-asymptotes method, in conjunction with the fin analogy model, is employed to build the optimization model for maximum heat transfer rate. A non-dimensional parameter is introduced to couple the two objectives—structural and thermal—in a single cost function. It is found that the geometry corresponding to maximum heat transfer rate is not unique, and square-celled core sandwich cylinders outperform those having triangular cells. The eight-layered sandwich cylinders with square cells have the best overall performance in comparison with other core topologies. Whilst a sandwich cylinder with shorter length is preferred for enhanced thermo-mechanical performance, the influence of the outer radius of the cylinder is rather weak. 相似文献
97.
98.
Proteomic analysis of cellular soluble proteins from human bronchial smooth muscle cells by combining nondenaturing micro 2DE and quantitative LC‐MS/MS. 2. Similarity search between protein maps for the analysis of protein complexes
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Human bronchial smooth muscle cell soluble proteins were analyzed by a combined method of nondenaturing micro 2DE, grid gel‐cutting, and quantitative LC‐MS/MS and a native protein map was prepared for each of the identified 4323 proteins [1]. A method to evaluate the degree of similarity between the protein maps was developed since we expected the proteins comprising a protein complex would be separated together under nondenaturing conditions. The following procedure was employed using Excel macros; (i) maps that have three or more squares with protein quantity data were selected (2328 maps), (ii) within each map, the quantity values of the squares were normalized setting the highest value to be 1.0, (iii) in comparing a map with another map, the smaller normalized quantity in two corresponding squares was taken and summed throughout the map to give an “overlap score,” (iv) each map was compared against all the 2328 maps and the largest overlap score, obtained when a map was compared with itself, was set to be 1.0 thus providing 2328 “overlap factors,” (v) step (iv) was repeated for all maps providing 2328 × 2328 matrix of overlap factors. From the matrix, protein pairs that showed overlap factors above 0.65 from both protein sides were selected (431 protein pairs). Each protein pair was searched in a database (UniProtKB) on complex formation and 301 protein pairs, which comprise 35 protein complexes, were found to be documented. These results demonstrated that native protein maps and their similarity search would enable simultaneous analysis of multiple protein complexes in cells. 相似文献
99.
A numerical parametric study of the flow field which develops when a planar shock wave impinge on a rigid porous material
is presented. This study complements an earlier study (Levy et al. 1996a) where the values of some dominating parameters were
estimated and the dependence of the resulting flow field on these values was not checked.
Received 22 April 1996 / Accepted 5 January 1997 相似文献
100.
Foamed materials are increasingly finding application in engineering systems on account of their unique properties. The basic mechanics which gives rise to these properties is well established, they are the result of collapsing the foam microstructure. Despite a basic understanding, the relationship between the details of foam microstructure and foam bulk response is generally unknown. With continued advances in computational power, many researchers have turned to numerical simulation to gain insight into the relationship between foam microstructure and bulk properties. However, numerical simulation of foam microscale deformation is a very challenging computational task and, to date, simulations over the full range of bulk deformations in which these materials operate have not been reported. Here a particle technique is demonstrated to be well-suited for this computational challenge, permitting simulation of the compression of foam microstructures to full densification. Computations on idealized foam microstructures are in agreement with engineering guidelines and various experimental results. Dependencies on degree of microstructure regularity and material properties are demonstrated. A surprising amount of porosity is found in fully-densified foams. The presence of residual porosity can strongly influence dynamic material response and hence needs to be accounted for in bulk (average) constitutive models of these materials. 相似文献