Robust control of polytopic systems by convex optimization

Robust control synthesis of linear time-invariant SISO polytopic systems is investigated using the polynomial approach. A convex set of all stabilizing controllers for a polytopic system is given over an infinite-dimensional space. A finite-dimensional approximation of this set is obtained using the orthonormal basis functions and represented by a set of LMIs thanks to the KYP lemma. Then, an LMI based convex optimization problem for robust pole placement with sensitivity function shaping in two- and infinity-norm is proposed. The simulation results show the effectiveness of the proposed method.     

Varying Electron Cyclotron Resonance Heating on the Levitated Dipole Experiment

Plasmas in the Levitated Dipole Experiment (LDX) are formed and sustained currently via two electron cyclotron resonance heating (ECRH) sources: 2.5 kW at 2.45 GHz and 2.5 kW at 6.4 GHz. An important topic being investigated is how varying the ECRH affects the confinement and stability of the plasma. We report the results of using different operational combinations of our RF sources, such as varying the power composition, changing the power levels, and sequencing of the onset time.     

压力容器材料质量控制的几个重要环节

针对压力容器材料方面存在的问题,从设计、采购、检验、制造等环节进行了分析,根据实际情况确定材料的质量控制要点。材料使用前要通过各种检测手段,判断材料的真实性,确保所用材料合格;并应从设计、选材、采购、计划、填报内容和选择可靠的供应方等方面加以控制,确保材料的正确使用,为压力容器产品的材料控制提供借鉴。     

Modeling of a multisector ecological economic system with lags

A model of a diversified ecological economic system with lags is proposed and investigated using sufficient optimality conditions. A turnpike solution of the problem, boundary trajectories, and control switchpoints are found. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 114–122, March–April 2007.     

川东北五宝场构造沙溪庙组储层特征

五宝场构造中侏罗统沙溪庙组气藏是目前川东北地区在沙溪庙组地层中首先发现的气藏，也是川渝地区低效油气合作开发的重点目标。为此，通过沉积相、物性、横向分布等多方面分析研究，确定沙溪庙组储层具有以下特征：以中砂质粗粒、粗砂质中粒岩屑长石砂岩为主，岩性质纯、性脆；具有低胶结物含量、低成分成熟度、高结构成熟度岩石学特征；储集空间可分为洞穴、孔隙、裂缝和喉道3大类12个亚类，以次生溶孔为主要储集空间；裂缝是油气渗滤的主要通道，储集类型以裂缝-孔隙型为主；孔隙结构特征表现为：分选中等偏低、中低孔隙度中小喉型；加砂压裂对沟通储层、改造储层效果较好；沙二段底部嘉祥寨砂岩储层物性好、横向可追踪，是勘探首选产气层。     

温度场下超长楼板中抗裂筋的定量分析

本文对超长结构楼板在温度场下的行为进行理论研究和计算分析，并推导简便可行的计算公式。为超长楼板抗裂筋设计提供定量的方法，可供相关专业技术人员参考。     

出口小麦淀粉品质指标结果情况分析

对出口小麦淀粉企业实验室检测结果进行质量控制,防止在检验过程中产生质量隐患。对2005年1～4月份间出口的小麦淀粉抽取水分、灰分、二氧化硫等项目的实验室数据进行统计分析,绘制质量控制图。发现第18组水分数据失控,发现灰分数据从第10组起连续5个数据有位移的倾向。对于实施过程检验的企业,检验检疫部门应加强对生产过程控制的同时,更要对实验室进行质量控制,从而真正有效地保证检验工作质量。     

大型活塞式压缩机弹性隔振基础的设计及安装

大型活塞式压缩机基础转速较低,传统上采用固定大块体结构,不仅基础的体积和重量都很大,而且动力计算模型也比较复杂,设计参数具有不确定性。而弹簧隔振基础结构边界条件简单清晰,解除了设备、基础块与下部结构的刚性动态耦合,受力明确,构造简单,可靠性和准确度高;隔振效率高达80%以上,能大大降低设备本身和对下部结构的动力作用。文章结合胜利油田油气集输总厂一工程实例,从结构型式、隔振原理、物理参数、动力分析几方面介绍了弹性隔振基础的设计,并简要介绍了弹性隔振基础的安装要点。     

A Macro Model of Frequently Changing Mobile Networks to Perform Flow and Access Control

The area covered by a mobile ad hoc network consists of obstacles that inhibit transmission and areas where communications can take place. Physical structures, such as buildings, that block transmission, or lakes, where forwarding nodes cannot be located, are permanent obstacles. Temporary obstacles are created as mobile nodes enter or leave an area. Our hypothesis is that the spaces between nearby obstacles are bottlenecks that inhibit the flows in the network. We partition the network into areas that are encompassed by obstacles and bottlenecks. All of the nodes in an area are treated as a single super node, and the bottlenecks between areas are the links between the super nodes. As individual nodes move, the flows and paths in the model change more slowly than the paths and flows between the individual nodes. We apply flow control algorithms to the model and perform admission control within a super node based on the flows that are assigned by the flow control algorithm. We apply the model to the Columbia University campus, and use max–min, fair bottleneck flow control to assign the flows. Our hypothesis is verified for this example.