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151.
采用超声焊接铝合金箔材的工艺修复处理表面腐蚀受损的2A12CZ基体,并利用Quanta200型环境扫描电子显微镜分析了截面形貌及箔材与基体之间界面表面断口的微观形貌。结果表明：从截面来看,箔材与基体之间大部分发生了焊合,界面分界线大部分消失;从机械脱开的界面断口来看,其表面微观形貌表现为鳞片状及韧窝状的典型金属型断口形貌。这说明在给定条件下,焊接部位大部分呈冶金结合。最后对铝台金箔材与铝合金基体之间超声焊接机理进行了探讨。 相似文献
152.
装配式管线是一种重要的油料保障装备,用于地面铺设,属于典型的薄壁弱约束管线系统。根据装配式管线的特点,应用管道弹性变形理论,推导了水力瞬变状态下装配式管线的非线性流固耦合5-方程模型。该模型充分考虑了管道与流体之间的耦合互动效应,耦合形式包含了泊松耦合、摩擦耦合、结合部耦合,以及管线系统的轴向、横向和径向振动耦合,并计及了管道结构阻尼的影响。针对装配式管线的特殊连接约束方式,提出了一种带有扭转弹簧的铰支型约束边界,可通过确定扭转弹簧的弹性系数来建立管线两端的约束边界方程。 相似文献
153.
程序控制流图不能表示DA交互发生点处实际执行的SQL语句,因而不能清晰地表示出程序数据库的交互过程。针对该问题提出了用有限状态自动机表示DMLSQL语句,根据自动机的运行过程确定交互语句使用或定义的数据对象,并利用此信息生成表示交互语句的结点,以扩展CFG。实验表明,经过扩展后的ECFG能够直观地表示DA程序中与数据库的交互结构。 相似文献
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155.
Consider a set of product variants that are differentiated by some secondary attributes such as flavor, color, or size. The retailer's problem is to jointly determine the set of variants to include in her product line (“assortment”), together with their prices and inventory levels, so as to maximize her expected profit. We model the consumer choice process using a multinomial logit choice model and consider a newsvendor type inventory setting. We derive the structure of the optimal assortment for some important special cases, including the case of horizontally differentiated items, and propose a dominance relationship for the general case that simplifies the search for an optimal assortment. We also discuss structural properties of the optimal prices. Finally, motivated by our analytical results, we propose a heuristic solution procedure, which is shown to be quite effective through a numerical study. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
156.
We study competitive due‐date and capacity management between the marketing and engineering divisions within an engineer‐to‐order (ETO) firm. Marketing interacts directly with the customers and quotes due‐dates for their orders. Engineering is primarily concerned with the efficient utilization of resources and is willing to increase capacity if the cost is compensated. The two divisions share the responsibility for timely delivery of the jobs. We model the interaction between marketing and engineering as a Nash game and investigate the effect of internal competition on the equilibrium decisions. We observe that the internal competition not only degrades the firm's overall profitability but also the serviceability. Finally, we extend our analysis to multiple‐job settings that consider both flexible and inflexible capacity. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008 相似文献
157.
We investigate and compare the impact of the tax reduction policies implemented in the United States and China to stimulate consumer purchase of new automobiles and improve manufacturers' profits. The U.S. policy provides each qualifying consumer with a federal income tax deduction on state and local sales and excise taxes paid on the purchase price (up to a cutoff level), whereas the Chinese policy reduces the vehicle sales tax rate for consumers. We observe that these policy designs are consistent with the tax management system and the economic environment in the respective country. We analytically determine the effects of the two tax reduction policies on the automobile sales and the manufacturer's and the retailer's profits. Numerical examples are then used to provide insights on the importance of certain factors that influence the effects of the two policies. Finally, a numerical experiment with sensitivity analysis based on real data is conducted to compare the merits and characteristics of the two policies under comparable conditions. We find that the U.S. policy is better than the Chinese policy in stimulating the sales of high‐end automobiles, whereas the Chinese policy is better than the U.S. policy in improving the sales of low‐end automobiles. The U.S. policy is slightly more effective in increasing the profitability of the automobile supply chain; but, in general, the Chinese policy is more cost effective. The methodology developed herein can be used to evaluate other tax reduction policies such as those related to the purchase of energy‐saving vehicles and to serve as a decision model to guide the choice of alternative tax reduction policies. © 2014 Wiley Periodicals, Inc. Naval Research Logistics, 61: 577–598, 2014 相似文献
158.
现代战场上的信息来源繁多、瞬息万变,这对战场指挥决策提出新的要求,而现有人机交互系统未能向指挥人员提供高效、自然、全面的人机交互。为解决该问题提出一种面向战场指挥决策的多通道多智能体交互模型,针对战场不同的领域,实现\"以人为中心\"的人机交互,使指挥人员能够自然、无障碍地将交互信息准确传递给系统,具有很好的可靠性和可扩展性。 相似文献
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160.
聚碳硅烷／二乙烯基苯快速升温裂解制备Cf/SiC复合材料 总被引：2，自引：0，他引：2
以聚碳硅烷(PCS)/二乙烯基苯(DVB)为先驱体,采用快速升温裂解制备了3D-B Cf/SiC复合材料.结果证明:裂解升温速率的提高可以大大缩短制备周期,同时可以提高材料密度和形成较好的界面结合,从而提高材料的力学性能.制备得到的Cf/SiC材料室温弯曲强度达到556.7MPa. 相似文献