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921.
922.
建立了反射端面为弧形形变的光纤F P传感腔数学模型.将弧形形变的F P腔等效为阶梯分布的、环状、平行端面F P腔体的组合,结合多光束干涉理论,利用光强叠加处理方法对弧形腔输出光强进行数学建模.依所建模型仿真,提出弧形端面曲率大于300 μm时,利用弧形形变特性进行传感测量的可行性.选取腔长变动大、形变弧度小,平衡状态稳定性高的形变端面保证传感腔的高灵敏度和稳定的工作点. 相似文献
923.
In the present study, a generalized nonlocal beam theory is proposed to study bending, buckling and free vibration of nanobeams. Nonlocal constitutive equations of Eringen are used in the formulations. After deriving governing equations, different beam theories including those of Euler–Bernoulli, Timoshenko, Reddy, Levinson and Aydogdu [Compos. Struct., 89 (2009) 94] are used as a special case in the present compact formulation without repeating derivation of governing equations each time. Effect of nonlocality and length of beams are investigated in detail for each considered problem. Present solutions can be used for the static and dynamic analyses of single-walled carbon nanotubes. 相似文献
924.
DING Huai-Bo ZHU Sheng-Jiang J.H. Hamilton A.V. Ramayya J. K. Hwang K. Li S.H. Liu Y.X. Luo J.O. Rasmussen C.T. Goodin I. Y. Lee WANG Jian-Guo CHE Xing-Lai GU Long 《中国物理C(英文版)》2009,33(Z1)
Levels in the neutron-rich 109Ru have been studied by observing the prompt γ-rays following the spontaneous fission fragments of 252Cf. The ground state band and the negative parity bands have been confirmed and extended. A positive parity band with the band head level at 332.5 keV is newly identified and suggested as a single-neutron excitation band built on the 7/2+ [404] Nilsson orbital. Some structural characteristics of these bands are discussed. 相似文献
925.
We propose a new method for determining order-up-to levels for intermittent demand items in a periodic review system. Contrary to existing methods, we exploit the intermittent character of demand by modelling lead time demand as a compound binomial process. In an extensive numerical study using Royal Air Force (RAF) data, we show that the proposed method is much better than existing methods at approximating target service levels and also improves inventory-service efficiency. Furthermore, the proposed method can be applied for both cost and service oriented systems, and is easy to implement. 相似文献
926.
假设供应商向零售商提供信用支付期的同时,零售商也向顾客提供信用支付期,研究了两货栈的变质物品库存模型,并讨论了模型最优解的唯一性,最后给出了最优订购策略的算法步骤与数值例子. 相似文献
927.
In the present work, the electronic and optical properties of anisotropic parabolic quantum disks are studied in the presence of an applied magnetic field. For this goal, we first obtain the electron energy levels of an anisotropic parabolic quantum disk under axial, tilted, and in-plane magnetic fields. According to the results obtained for the energy levels reveal that there is no degeneracy at zero magnetic field due to symmetry breaking. With increasing the anisotropy, the energy level spacing increases. At a constant anisotropy, the energy levels splitting decreases with increasing tilt angle of magnetic field. The total refractive index changes decrease when the tilt angle of magnetic field and the anisotropy increase. Also, the total absorption coefficients increase as the tilt angle of magnetic field and anisotropy increase. 相似文献
928.
在最弱受约束电子势模型理论框架下计算了W I原子的 , 和 系列里德堡能级,结果与实验值符合较好,最大相对误差均在2.72408E-6之内,达到了很高的精度. 相似文献
929.
Jingli Du Hong BaoChuanzhen Cui Dongwu Yang 《Finite Elements in Analysis and Design》2012,48(1):1392-1399
In conventional researches, cables of cable-driven parallel manipulators are treated as simple linear elements that can only work in tension. This results in the fact that the effect of cable dynamics on the positioning precision of the end-effector is not adequately taken into account. To overcome this shortcoming, a dynamic model for cable-driven parallel manipulators with cables of slowly time-varying length is presented in this paper. The partial differential equation characterizing the dynamics of a cable with varying-length is deduced, and converted into ordinary differential equations through spatial discretization by finite difference approximation. Then, the dynamic model for cable-driven parallel manipulators is achieved considering the relationship between the motion of the end-effector and the cable end force, in which the degrees of freedom of cables and the end-effector are all involved. Two numerical examples are demonstrated to validate the dynamic model, and also show that it is necessary to take into consideration the cable dynamics for manipulators of long-span cables. 相似文献
930.
《Optimization》2012,61(2):283-289
An inventory system with unit demand, varying ordering levels and random lead times is considered in this paper. Ordering level is determined by the number of demands during last lead time. The ordering quantity will be such as to bring back the inventory level to S at the ordering epoch. No backlog is permitted. The time dependent probability distribution of the inventory level is obtained. Correlation between the number of demands during a lead time and the length of the next inventory dry period is obtained and it is illustrated by an example. 相似文献