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991.
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993.
提出了一种改进的、可用于计算偏振相关拉曼增益的光纤拉曼放大器的非线性耦合波方程。建立了单模双折射光纤拉曼增益的数学模型,分析了线偏振抽运光以与光纤快轴成45°激励的单模双折射光纤拉曼放大器模型与实际具有随机双折射的光纤拉曼放大器的拉曼增益偏振相关特性的等价性。基于上述模型,提出了一个可定量表征单模光纤偏振模色散统计特性的拉曼增益偏振相关因子,用以替代常规的光纤拉曼放大器非线性耦合波方程中的偏振相关因子。计算结果与已报道文献的实验数据非常吻合。同时对抽运增益在同向和反向抽运方式下截然不同的增益偏振相关特性给出了合理的解释。 相似文献
994.
995.
《Operations Research Letters》2019,47(5):386-390
This paper examines a special case of multi-facility location problems where the set of demand points is partitioned into a given number of subsets or clusters that can be treated as smaller independent sub-problems once the number of facilities allocated to each cluster is determined. A dynamic programming approach is developed to determine the optimal allocation of facilities to clusters. The use of clusters is presented as a new idea for designing heuristics to solve general multi-facility location problems. 相似文献
996.
This paper addresses systematic longevity risk in long-term insurance business. We analyze the consequences of working under unknown survival probabilities on the efficiency of the Law of Large Numbers and point out the need for appropriate and feasible risk management techniques. We propose a setting for risk sharing schemes between the insurer and policyholders via a dynamic equivalence principle. We focus on a pure endowment contract and derive conditions for a viable risk sharing scheme which enhances the solvency situation of the insurer while being more favorably priced for the policyholders. 相似文献
997.
We embed an approximate dynamic program into a branch-and-bound framework to solve sequential resource allocation problems in population disease management. The proposed algorithm is capable of providing an optimality guarantee and getting bounds on the optimality gap of healthcare interventions. A numerical study on screening and treatment policy implementation for chronic hepatitis C virus (HCV) infection provides useful insights regarding HCV elimination for baby boomers. 相似文献
998.
When a solid sphere exits water at a given velocity, the liquid column is pulled out of a liquid reservoir. The present study focuses on the dynamic deformation of the liquid column and on the identification of the liquid column regime on the Weber number and dimensionless time (We-t*) map. The three-dimensional model of water exit has been established on the basis of the lattice Boltzmann method. A mass tracking algorithm was incorporated to capture the free surface, where the liquid–gas two-phase flow is simplified to a single-phase free surface flow. The surface tension is included by adding a perturbation term and the gravity as a body force is introduced in form of calculating the equilibrium distribution with an altered velocity. The contact angle condition in numerical simulation is not considered. The accuracy of the numerical results is demonstrated through the comparisons with the prior numerical and the experimental results in the literature. A parametric study has been conducted numerically on the radius and volume and of liquid column. Besides, the relationship between the pinch-off time of a liquid column and the Froude number has been obtained. Moreover, the evolution of the liquid column shape with a wide range of the Weber number and time scales are discussed based on the number of ligaments and droplets. The liquid column exhibits different characteristics and has been divided into three regimes. The transition between different regimes has been analyzed and the critical Weber number is given. 相似文献
999.
1000.
提出了一种基于环形芯铒离子部分掺杂光纤的涡旋光纤放大器。针对该掺铒光纤的放大特性,研究了光纤长度、掺铒浓度与抽运功率对信号模式增益特性的影响。研究结果表明,该光纤放大器能够支持22个轨道角动量模式稳定传输,且C波段(1530~1565 nm)所有信号模式增益大于23 dB,信噪比高于27 dB,差分模式增益小于0.015 dB。所提出的基于环形芯光纤的涡旋光纤放大器具有支持轨道角动量模式数量多、差分模式增益低、信噪比高的优势,对于OAM复用长距离传输系统中的在线放大具有重要参考价值。 相似文献