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间歇式高速同步相机新型全数字化微机控制系统 总被引:2,自引:2,他引:0
本文提出了一种间歇式高速同步相机的全新设计方法,介绍了系统的工作原理,硬件,软件设计以及核心控制算法,最后给出了实际应用结果。 相似文献
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几率量子隐形传态的离子阱方案 总被引:2,自引:0,他引:2
本文提出了一个在分别囚禁于不同离子阱中的两个离子间实现几率量子隐形传态的简单方案,Alice对离子1和离子2的内态进行联合测量并通过经典通道告诉Bob测量结果,Bob利用一束经典驻波场激光与离子3相互作用并控制相互作用的时间就能够在离子3上最佳几率地重现离子1的初始内态. 相似文献
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Arnon Arazi Eshel Ben-Jacob Uri Yechiali 《Mathematical Methods of Operations Research》2005,62(3):453-466
We consider a Jackson-type network comprised of two queues having state-dependent service rates, in which the queue lengths
evolve periodically, exhibiting noisy cycles. To reduce this noise a certain heuristic, utilizing regions in the phase space
in which the system behaves almost deterministically, is applied. Using this heuristic, we show that in order to decrease
the probability of a customers overflow in one of the queues in the network, the server in that same queue – contrary to intuition
– should be shut down for a short period of time. Further noise reduction is obtained if the server in the second queue is
briefly shut down as well, when certain conditions hold. 相似文献
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The turbulent flow in a compound meandering channel with a rectangular cross section is one of the most complicated turbulent flows, because the flow behaviour is influenced by several kinds of forces, including centrifugal forces, pressure‐driven forces and shear stresses generated by momentum transfer between the main channel and the flood plain. Numerical analysis has been performed for the fully developed turbulent flow in a compound meandering open‐channel flow using an algebraic Reynolds stress model. The boundary‐fitted coordinate system is introduced as a method for coordinate transformation in order to set the boundary conditions along the complicated shape of the meandering open channel. The turbulence model consists of transport equations for turbulent energy and dissipation, in conjunction with an algebraic stress model based on the Reynolds stress transport equations. With reference to the pressure–strain term, we have made use of a modified pressure–strain term. The boundary condition of the fluctuating vertical velocity is set to zero not only for the free surface, but also for computational grid points next to the free surface, because experimental results have shown that the fluctuating vertical velocity approaches zero near the free surface. In order to examine the validity of the present numerical method and the turbulent model, the calculated results are compared with experimental data measured by laser Doppler anemometer. In addition, the compound meandering open channel is clarified somewhat based on the calculated results. As a result of the analysis, the present algebraic Reynolds stress model is shown to be able to reasonably predict the turbulent flow in a compound meandering open channel. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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A highly sensitive method for infrared radiation detection based on thermal resonance in an active bolometer is set forth. An active bolometer is a self-oscillating system consisting of an IR-sensitive cell in a feedback circuit of an adjustable proportional controller. The analysis of an active bolometer autonomous (dark) dynamics reveals that with a generalized gain factor A variation the system evolves from relaxation type towards oscillating and self-oscillating type. When A=Ac, where Ac is a critical value of the generalized gain factor A, the steady state loses stability through self-excited thermal oscillations. The resonance in a system weakly perturbed by IR radiation modulated at self-oscillation frequency q0[1+exp(iωct)] is considered. It is shown that in a small precritical vicinity =(A−Ac)/Ac of the gain factor the amplitude of forced thermal oscillations is proportional to q0/Ac. The D* calculation reveals that the detection power of a passive (A=0) bolometer increases with feedback introduction by a factor of 1/||. The detection powers of feasible versions of an active bolometer are compared. 相似文献
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Summary We consider the problem of maximizing the discounted net profit of a firm which purchases a quantity of some product at a
given time and afterwards advertises and sells the product progressively. We distinguish among the three possibilities of
assuming the final time to be either fixed, or bounded, or free. In all cases, after stating the problem in the optimal control
theory framework, we prove the existence of an optimal solution and characterize it using the Maximum Principle necessary
conditions. Furthermore, we prove that the convexity of the purchase cost function is a sufficient condition for the uniqueness
of the optimal solution.
Partially supported by MURST. 相似文献