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61.
研究了磁场中液氦薄膜表面电子与涟波子强耦合和弱耦合的性质。采用线性组合算符方法导出磁场中液氦薄膜表面电子 涟波子系统的振动频率和基态能量。讨论磁场对表面电子 涟波子系统的振动频率和基态能量的影响。 相似文献
62.
The joint supply of timber and other services from forest environments plays a central role in most forest land debates. This paper defines a general conceptual model of timber supply that provides the context for discussing both individual harvest choice and aggregate supply models. While the structure and breadth of these models has developed considerably over the last twenty years, unresolved issues remain. Supply formulations that account for the quality and vintage distribution of forest capital will be necessary for improving medium- and long-run forecasts. This will be especially important for examining the potential impacts of structural changes in forest production and timber markets. In addition, consistent aggregation of individual owners to total supply will be required to address changing forest land ownership patterns. 相似文献
63.
The problem of scheduling the production and delivery of a supplier to feed the production of F manufacturers is studied. The orders fulfilled by the supplier are delivered to the manufacturers in batches of the same size. The supplier's production line has to be set up whenever it switches from processing an order of one manufacturer to an order of another manufacturer. The objective is to minimize the total setup cost, subject to maintaining continuous production for all manufacturers. The problem is proved to be NP-hard. It is reduced to a single machine scheduling problem with deadlines and jobs belonging to F part types. An O(NlogF) algorithm, where N is the number of delivery batches, is presented to find a feasible schedule. A dynamic programming algorithm with O(N
F
/F
F–2) running time is presented to find an optimal schedule. If F=2 and setup costs are unit, an O(N) time algorithm is derived. 相似文献
64.
65.
The variational method using a multiconfiguration wavefunction is carried out on the core-excited state 1s2s2p 4P0 for helium negative ion,including mass polarization and relativistic corrections.Binding energy and fine structure are reported.The results are compared with other theoretical and experimental date in the literature. 相似文献
66.
H. Totsuji 《等离子体物理论文集》2012,52(1):74-77
The conduction of electrons through narrow channels formed on the surface of liquid helium is analyzed by numerical simulations. It is shown that, when electrons are strongly coupled, we have nonlinear and even negative dependence of conductance on the width of the constriction which is controlled by the gate voltage (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
67.
We discuss recent observations of the heat capacity and magnetization of a fluid 3He monolayer adsorbed on graphite plated with a bilayer of HD. Approaching the density at which the monolayer solidifies into a
commensurate solid, we observe an apparent divergence of the effective mass. However, the inferred values of F0a tend to a constant. We interpret this in terms of a Mott–Hubbard transition between a 2D Fermi liquid and a magnetically disordered solid occurring via the Brinkman–Rice–Anderson–Vollhardt scenario. 相似文献
68.
分散化供应链的自组织演化机制建模与仿真 总被引:1,自引:0,他引:1
供应链是一个复杂适应系统.提出了分散化供应链演化的自组织机制.在开放结构下,多企业主体为了适应外部环境,在非线性互动中涌现出供应链协作结构和协调模式.借鉴生物系统环境适应能力思想,建立了分散化供应链自组织演化模型,并采用Multi-agent技术进行仿真,证明了分散化供应链的自组织演化机制.外部环境和企业内部机制因素控制着分散化供应链的演化,其演化对初始条件高度敏感,存在着锁定、路径依赖和混沌等自组织系统特性. 相似文献
69.
C.D. Tarantilis C.T. Kiranoudis N.D. Theodorakopoulos 《European Journal of Operational Research》2008
A Web-based ERP system developed for attacking business problems and managing real-world business processes ranging from simple office automation procedures to complicated supply chain planning is presented. The system’s Web-aspect provides significant advantages, as the system is distributed through interoperable, cross-platform and highly pluggable Web-service components. The system involves a powerful workflow engine that manages the entire process event flow within the enterprise increasing efficiency and control at the same time. Business processes, when needed, are controlled by the enterprise quality management system and consequently the ISO directives are accurately followed. A real-world process scheduling system developed for the specific needs of Greek Construction Manufacturing Enterprises is illustrated as a detailed paradigm of the system’s capabilities. The problem was formulated to assign project tasks in form of lots to enterprise resources in order that resources idle time and delays in project preparation time were minimized. The problem was solved by a simple and effective heuristic algorithm. 相似文献
70.