ZG35CrMnSiRe热处理的试验研究

ZG35CrMnSiRe铸钢经不同的热处理,对其强度、硬度、塑性和冲击韧性等机械性能进行测定,实验结果表明其综合机械性能良好。     

基于空化的机械密封槽腔耦合方式研究

为了研究机械密封端面槽腔耦合造型对性能的影响,以获得最佳槽腔耦合方式,建立了4个不同槽腔耦合方案和1个无开腔上游泵送密封方案的物理模型和计算模型,利用Fluent空化模型进行内流场计算和分析,并进行试验验证.研究表明:不是任意的槽腔耦合方式都能增强密封环的开启性和稳定性,对于所研究的密封结构和尺寸,相比于未加工微凹腔的上游泵送机械密封环,只有将微凹腔开设在动环坝区时才能够增强密封环的开启性和稳定性,且具有较低的摩擦力;转速越高,合理的槽腔耦合机械密封增强开启性和稳定性的优势越明显.     

The Dynamics Characteristics of Flexible Spacecraft and its Closed-Loop Stability with Passive Control

Passive control is the most popular methodology for flexible spacecraft while it remains an open problem whether the closed-loop performance can be achieved only with passive control subject to the coupling modes of rigid and flexibility. Also, the closed-loop performance of passive PD control based on the dynamics of the Euler angle parameterization of spacecraft, which has been widely used in practice, is yet to be addressed. Towards these challenges, by introducing the input-output exact linearization theory and Lyapunov theory, the authors show that the closed-loop performance for flexible spacecraft with rigid and flexible modes can be achieved by adjusting the parameters of the passive controllers sufficiently large. This is done by firstly transforming the flexible spacecraft dynamics into an exact feedback linearization standard form, and then analyzing the closed-loop performance of flexible spacecraft.     

低温微生物的研究进展概述

综述了低温微生物的生态分布、适冷机制的研究进展及其在工业、生物修复等多个领域中的应用及前景.     

Predictive Event-Triggered Control for Disturbanced Wireless Networked Control Systems

The control and scheduling for wireless networked control system with packet dropout and disturbance are investigated. A prediction based event triggered control is proposed to reduce data transmissions while preserving the robustness against external disturbance. First, a trigger threshold is especially designed to maintain the difference of the estimated and actual states below a proper boundary when system suffers from packet dropout. Then a predictive controller is designed to compensate for packet dropouts by utilizing the packet-based control approach. The sufficient conditions to ensure the closed-loop system being uniformly ultimately bounded are derived, with consequently the controller gain method. Numerical examples illustrate the effectiveness of the proposed approach.     

基于灰色关联度的应急避难场所找寻行为研究

应急避难场所作为应对城市突发公共事件的灾民安置基础设施,对保障城市居民安全具有重要作用。目前对应急避难场所的研究主要集中在选址布局等方面,而针对应急避难场所的可达性研究较少。本文通过18名测试人员在北京市户外实地测试,取得了对找寻应急避难场所耗时产生影响的因素,然后通过灰色关联度法研究各因素影响程度,最后提出优化应急避难场所可达性建议。结果表明：注视电子导航的次数对找寻应急避难场所耗时影响程度最大,其次分别为注视电子导航总时长、手机旋转次数与折返行为次数。     

智能制造与创新的耦合关系:基于扎根理论的探索性研究

为更好地推动制造业智能化转型,智能制造与创新的关系亟待厘清.运用扎根理论方法对双环传动和海尔集团开展探索性研究,剖析智能制造与创新之间的耦合关系.研究发现,智能制造促进产品创新和流程创新;同时创新是智能制造发展的动力,它促进智能产品形成,为智能生产提供重要支撑,推动智能制造基础设施建设以及智能制造模式转变.两者之间相互...     

一种无线传感器网络的数据包编码加密算法设计

为了提高无线传感器网络的生命周期,利用基本算术指令的运算,提出一种无线传感器网络的数据包编码加密的算法.此算法利用非线性随机异或操作,对无线传感器网络中传递的数据包进行加密.试验结果表明,减小无线传感器网络加密算法的复杂度,可以明显降低无线传感器网络的能量消耗.同时提出的数据包编码加密算法可以明显降低无线传感器网络的能量消耗,有利于无线传感器网络生命周期的延长.相比于现有的公共或对称钥匙方案,所提出的方法更加节能更有效.     

Observation of robust edge superconductivity in Fe(Se,Te) under strong magnetic perturbation

The iron-chalcogenide high temperature superconductor Fe(Se,Te) (FST) has been reported to exhibit complex magnetic ordering and nontrivial band topology which ...     

基于CORBA的分布式数据库系统开发技术

介绍了用Delphi5.5开发基于CORBA的分布式数据库系统的方法,以及开发过程中需要注意的问题,举例说明了服务器端和客户端程序的设计与实现。