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851.
散度抛物型变分边值问题的周期解 总被引:2,自引:0,他引:2
本文应用单调算子方法,获得了散度抛物型变分边值问题在L~2(Ω)中的强周期解,并在低维空间(N≤3)对强解进行了正则化,证明了古典周期解的存在性,本文改进和推广了以往的结论。 相似文献
852.
The existence of strong solutions of Cauchy problem for the following evolution equation du(t)/dt+∂?1(u(t))-∂?2(u(t))∋f(t) is considered in a real reflexive Banach space V, where ∂?1 and ∂?2 are subdifferential operators from V into its dual V*. The study for this type of problems has been done by several authors in the Hilbert space setting.The scope of our study is extended to the V-V* setting. The main tool employed here is a certain approximation argument in a Hilbert space and for this purpose we need to assume that there exists a Hilbert space H such that V⊂H≡H*⊂V* with densely defined continuous injections.The applicability of our abstract framework will be exemplified in discussing the existence of solutions for the nonlinear heat equation: where Ω is a bounded domain in RN. In particular, the existence of local (in time) weak solution is shown under the subcritical growth condition q<p* (Sobolev's critical exponent) for all initial data This fact has been conjectured but left as an open problem through many years. 相似文献
853.
Tiziana Cardinali 《Journal of Mathematical Analysis and Applications》2005,308(2):620-635
In this paper we deal with a Cauchy problem governed by the following semilinear evolution differential inclusion:
x′(t)∈A(t)x(t)+F(t,x(t)) 相似文献
854.
Gärtner S Küllmer J Schlottmann U 《Angewandte Chemie (International ed. in English)》2003,42(37):4456-4469
The title of this article is the motto of the fourth meeting of the Intergovernmental Forum on Chemical Safety (Forum IV), which is to be held in Bangkok in November 2003. The IFCS has been in existence for 10 years. During this period politicians, scientists, and the general public have become increasingly aware of the risks associated with chemicals. International conventions providing for prohibitions and restrictions of dangerous chemicals, and for better control of trade have been set up. These conventions will soon be binding under international law. In developing countries many people who handle or use hazardous chemicals are illiterate or poorly educated; they may not fully understand what they are handling. The industrialized countries therefore have a special duty to incorporate chemical safety in development cooperation measures. Through their presence at this year's forum, prominent chemists such as Carl Djerassi will seek to underline the fact that a long term preventive approach to healthcare and the environment is only possible through international cooperation. This overview describes current developments in the field of chemical safety policy and presents a selection of the legislation currently in force for chemicals in the European Union. It also provides an insight into the interwoven structure of international cooperation that takes place at both the political and the technical level. 相似文献
855.
We examine crossing probabilities and free energies for conformally invariant critical 2-D systems in rectangular geometries, derived via conformal field theory and Stochastic Löwner Evolution methods. These quantities are shown to exhibit interesting modular behavior, although the physical meaning of modular transformations in this context is not clear. We show that in many cases these functions are completely characterized by very simple transformation properties. In particular, Cardy's function for the percolation crossing probability (including the conformal dimension 1/3), follows from a simple modular argument. A new type of higher-order modular form arises and its properties are discussed briefly. 相似文献
856.
A Markov model with a coordination parameter isdeveloped to depict coordination and cooperation decisionprocesses in 2 × 2 game relationships. The parameters ofthe model can be used to define and measure various forms ofinfluence. The model is applied to data collected using aprisoner's dilemma payoff structure to represent thesuperior-subordinate relationship. The results demonstrate theusefulness of the model and the measures of influence. Superiorsand subordinates are more likely to coordinate following mutualcooperation, achieving matching behaviors more frequently thanan independent-decisions model would predict. Subordinates showslightly more influence over leaders' behaviors than vice versa. 相似文献
857.
WANG Tie-Shan PENG Hai-Bo Ovsyannikov V P Kentsch U Ullmann F CHENG Rui Zschornack G 《中国物理C(英文版)》2008,32(5)
In this work.highly charged ions have been extracted from the advanced Electron Beam Ion Source (EBIS-A) developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresden.The charge state distributions of ions extracted from the EBIS-A are measured in and extracted in the leaky mode.3×105 Ar18+ ions per pulse are extracted in the pulse mode.The ion charge state distribution is a function of the ionization time. 相似文献
858.
We study the evolutionary snowdrift game in a heterogeneous Newman-Watts small-world network. The heterogeneity of the network is controlled by the number of hubs. It is found that the moderate heterogeneity of the network can promote the cooperation best. Besides, we study how the hubs affect the evolution of cooperative behaviours of the heterogeneous Newman-Watts small-world network. Simulation results show that both the initial states of hubs and the connections between hubs can play an important role. Our work gives a further insight into the effect of hubs on the heterogeneous networks. 相似文献
859.
Mingxia Xu Xiuyun Zhang Yaqi Liu Xinli Zhao Yongjun Liu Ruchun Wu Jinlan Wang 《Chemphyschem》2020,21(24):2651-2659
Single atom catalysts (SAC) for water splitting hold the promise of producing H2 in a highly efficient and economical way. As the performance of SACs depends on the interaction between the adsorbate atom and supporting substrate, developing more efficient SACs with suitable substrates is of significance. In this work, inspired by the successful fabrications of borophene in experiments, we systematically study the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) activities of a series of 3d transition metal-based SACs supported by various borophene monolayers (BMs=α_sheet, α1_sheet, and β1_sheet borophene), TM/BMs, using density functional theory calculations and kinetic simulations. All of the TM/BMs systems exhibit superior HER performance compared to Pt with close to zero thermoneutral Gibbs free energy (ΔGH*) of H adsorption. Furthermore, three Ni-deposited systems, namely, Ni/α_BM, Ni/α1_BM and Ni/β1_BM, were identified to be superior OER catalysts with remarkably reduced overpotentials. Based on these results, Ni/BMs can be expected to serve as stunning bifunctional electrocatalysts for water splitting. This work provides a guideline for developing efficient bifunctional electrocatalysts. 相似文献
860.
A game with precedence constraints is a TU game with restricted cooperation, where the set of feasible coalitions is a distributive lattice, hence generated by a partial order on the set of players. Its core may be unbounded, and the bounded core, which is the union of all bounded faces of the core, proves to be a useful solution concept in the framework of games with precedence constraints. Replacing the inequalities that define the core by equations for a collection of coalitions results in a face of the core. A collection of coalitions is called normal if its resulting face is bounded. The bounded core is the union of all faces corresponding to minimal normal collections. We show that two faces corresponding to distinct normal collections may be distinct. Moreover, we prove that for superadditive games and convex games only intersecting and nested minimal collection, respectively, are necessary. Finally, it is shown that the faces corresponding to pairwise distinct nested normal collections may be pairwise distinct, and we provide a means to generate all such collections. 相似文献