A New Nonlinear Controller for Trajectory Tracking of the Longitudinal Dynamics of a Small Scale Helicopter

A nonlinear control scheme is proposed for the trajectory tracking problem of a small scale helicopter’s longitudinal dynamics. The control scheme is based on a control design procedure that constructs static feedback regulators for nonlinear systems which are linearizable by dynamic feedback. Besides, the flatness characteristics of the helicopter’s longitudinal dynamics are used to design the desired trajectory. The controller proposed is based on the longitudinal model of the small scale helicopter including the main rotor and stabilizer bar dynamics. Sufficient conditions are given to guarantee asymptotic convergence to zero of the tracking error and to keep the main rotor thrust always negative assuming that all the helicopter’s parameters are known and that all helicopter’s states are measured. Numerical simulations are given to show the performance of the controller in the presence of the main rotor and stabilizer bar dynamics.     

并行企业运作--基于并行工程的过程企业管理

针对过程企业,基于并行工程的思想,提出了过程企业运作管理的新思想--并行企业运作,并采用IDEFO(ICAM Defintion)功能建模方法,建立了集成并行的业务过程模型,在每个业务过程内部采用"监控-决策-执行"的实时信息反馈系统,以实现企业各业务过程之间的信息交互与资源共享.     

Proposed Phenomenological PTCR Model and Accompanying Phenomenological PTCR Chart

The positive temperature coefficient of resistivity (PTCR) behavior of semiconductive BaTiO₃ is well explained by the Heywang model, which predicts the resistivity behavior above the Curie point based on the acceptor state density at the grain boundaries, the charge carrier density, and the energy gap, E _s, between the conduction band and the acceptor levels. However, the relationship between these parameters and the production parameters (sintering time, composition, and cooling rate) is not well understood. Recently, the present authors have found that E _s can be increased by thorough oxidation. This increase is attributed to a change in the oxidation state of the acceptor. Based on this finding and results from the literature, a phenomenological PTCR model and an accompanying PTCR chart for acceptor–donor-codoped BaTiO₃ are proposed to clarify this relationship. The PTCR chart clarifies that acceptor dopant concentrations, oxidation time, and oxygen partial pressure during oxidation or cooling can be optimized simultaneously to obtain optical PTCR properties.     

八碳烯分离工艺的研究

从能量综合集成的角度提出了八碳烯精馏分离工艺 ,对所提流程进行了优化模拟计算及分析 ,为八碳烯分离工艺的施工设计提供了充分的依据。投产情况表明 ,该研究改变了八碳烯的生产现状 ,使得八碳烯生产的经济效益显著提高     

智慧·创新·分享——大师贴膜品牌升级行业发布会举办

十年发展,十年沉淀,十年新起点!2013年12月9日,由上海追得贸易发展有限公司主办的"智慧·创新·分享"暨"大师贴膜品牌升级行业发布会"于上海兴荣温德姆五星级酒店隆重召开。时值企业成立十周年,大师贴膜品牌迎来了又一次里程碑式的跨越,追得企业也将迎来更加创新的发展模式。     

Exploration of mesoporous structure of tunisian raw and acid-leached phosphate ore particles

Rock phosphate fractions were examined for their porous structure by nitrogen adsorption. The pore size distribution and the shape of pores does not seem to depend on the particle size. The specific surface area values present two regions, one above and one below that of the particles with 125 μrn diameter. Particles of a given size were leached with dilute phosphoric acid (1.5 mass% P₂O₅) at 25°C. It was observed that there is a widening of the initial pores during leaching. The particles collected at the initial period of the reaction are pitted and those collected at the final period are disintegrated.     

重视产品本质,垂直整合通路——Sundef山迪打造源自美国的高性价比高端隔热膜品牌

正眼下,信息的日益透明化、渠道的日渐扁平化、消费的日趋理性化都给国内窗膜市场提出了新的要求,中美合资羿阳(Unisun)科技趁机而入,带来Sundef山迪品牌,给行业、给消费者带来了源自美国的高性价比高端产品选择。新时代下的消费新需求中国的太阳膜市场拥有近20年的发展历史,期间经历了多次变革。眼下,隔热膜已成为汽车     

三个半世纪的长盛传奇 圣戈班迎来350周年

正357面玻璃见证圣戈班的诞生巴黎凡尔赛宫,巴黎著名的宫殿之一,同时也是世界五大宫之一(北京故宫、法国凡尔赛宫、英国白金汉宫、美国白宫、俄罗斯克里姆林宫)。法国国王路易十四和路易十六最喜爱的住所,这里历经几代建筑师,雕塑家,装饰艺术家和风景画家的耕耘,成为一个世纪以来欧洲皇家住所的典范。1979年,凡尔赛宫和花园作为法国17世纪艺术的杰作被联合国教科文组织收入世界人文遗产名录。凡尔赛宫宏伟、壮观,它的内部陈设和装潢富于艺术魅力,名胜景观