基于复杂表面形状的端铣切削力模型

以传统的端铣切削力模型为基础,针对复杂加工表面形状,提出了一种更加符合实际加工情况的端铣切削力模型。该模型的建立涉及到复杂表面形状的几何表示、不同刀具轨迹的描述和刀齿-工件接触计算等关键技术。通过对模拟结果进行分析,验证了所建端铣切削力模型的有效性。     

电磁带隙结构单脊波导缝隙相控阵天线的实验研究

提出一种电磁带隙结构交错排列的单脊波导缝隙相控阵天线,并与相同尺寸的普通单脊波导缝隙相控阵天线作比较。测试结果表明该天线的方向图得到了明显的改善,单元之间的耦合系数减小,背瓣的辐射电平显著降低,扫描特性得到了改善;同时也说明了电磁带隙结构可以取得比扼流槽更好的抑制表面波的效果。这对于提高单脊波导缝隙相控阵天线的辐射性能具有重要意义。     

1420cs铝锂合金型材力学特性测试

用电测的方法 ,得到了材料的应力与纵向应变曲线及横向应变与纵向应变曲线 ,判读出σ0 2 、σb、E、μ ,测试结果表明 :过比例伸长应力后 ,横向变形有明显跳动 ,这种特性有别于其他材料 ,使用中应予注意 ;测试了表面裂纹的断裂韧度。     

超声速、高超声速球锥组合体表面压强估算方法及其应用

改进并推广了一种有效的球头单锥组合体在超声速和高超声速流动情况下的表面压力分布算法 ,并利用该算法对若干来流条件下球头双锥组合体表面的压力分布进行了计算。计算结果与数值计算结果以及文献实验数据的比较表明 :本文介绍的方法不失为一种适用范围较宽、准确程度较高的工程算法     

氙原子在铂表面散射的分子动力论方法

运用分子动力论方法研究气体分子 (Xe)在固壁表面 (Pt)的散射。在构造了合理的气体分子与固壁表面相互作用势模型之后 ,运用随机经典轨道方法求解气体分子及固壁原子的运动方程 ,得到气体分子运动轨迹及散射后的运动状态。结果表明 ,气体分子散射后的角度分布与Maxwellian模型存在较大差异 ,而速度基本服从半空间的Maxwellian分布。     

舰船建造费随批量变化的成长模型分析

应用微分方程、回归分析及生长曲线３段估算法,建立批量生产条件下舰船单价变化模型,这一模型可与其他模型综合应用以取得更理想的结果．     

电子战仿真系统中防空武器作战效能研究

介绍了电子战仿真系统总体结构,研究了空中拦截、地对空导弹及高炮等模块的作战效能模型,并用Ｍｏｎｔｅ Ｃａｒｌｏ 试验方法分析了系统的电子对抗作战效能     

Periodic review inventory management with contingent use of two freight modes with fixed costs

We study a stochastic inventory model of a firm that periodically orders a product from a make‐to‐order manufacturer. Orders can be shipped by a combination of two freight modes that differ in lead‐times and costs, although orders are not allowed to cross. Placing an order as well as each use of each freight mode has a fixed and a quantity proportional cost. The decision of how to allocate units between the two freight modes utilizes information about demand during the completion of manufacturing. We derive the optimal freight mode allocation policy, and show that the optimal policy for placing orders is not an (s,S) policy in general. We provide tight bounds for the optimal policy that can be calculated by solving single period problems. Our analysis enables insights into the structure of the optimal policy specifying the conditions under which it simplifies to an (s,S) policy. We characterize the best (s,S) policy for our model, and through extensive numerical investigation show that its performance is comparable with the optimal policy in most cases. Our numerical study also sheds light on the benefits of the dual freight model over the single freight models. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

基于聚类算法的多无人机系统任务分配

针对现有任务分配方法在任务点较多时不易解算,且计算量大的问题,提出了基于模糊C-均值聚类算法的多无人机系统任务分配方法.首先,利用模糊C-均值聚类算法得到的隶属度矩阵对任务点进行初始分配;其次,针对基于空间划分聚类可能造成各UAV任务不均衡的问题,设计任务的局部优化调整规则;最后,结合单旅行商问题,利用Tabu Sea...     

Quantifying the performance effects of idle time utilization in multiserver systems

In many practical multiserver queueing systems, servers not only serve randomly arriving customers but also work on the secondary jobs with infinite backlog during their idle time. In this paper, we propose a c‐server model with a two‐threshold policy, denoted by (e d), to evaluate the performance of this class of systems. With such a policy, when the number of idle servers has reached d (<c), then e (<d) idle agents will process secondary jobs. These e servers keep working on the secondary jobs until they find waiting customers exist in the system at a secondary job completion instant. Using the matrix analytic method, we obtain the stationary performance measures for evaluating different (e, d) policies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007.