高速冲压生产线上下料冗余机械臂的运动学分析

在应用于高速冲压生产线冗余机械臂姿态规划和轨迹优化过程中,以兼顾上下料效率与轨迹的平稳性为目的,对冗余机器臂的加加速度进行约束,基于旋量理论建立运动学模型,得到正运动学方程,采用遗传算法对冗余机械臂进行逆运动学分析,结合五次B样条插值方法,对末端执行器运动轨迹的加加速度进行优化。结果表明,该方案可有效提高上下料效率,保证冗余机械臂上下料过程运行平稳。     

基于WiMAX通信网络的电源监控系统的构建

分析了全球微波接入互存(WiMAX)的技术特点和算法复杂度,探讨了其在电源监控系统中的应用,提出了基于Inter WiMAX Connection 2250技术的远程电源监控系统。在讨论WiMAX物理层算法的基础上,确定了以正交频分多址(OFDMA)模式为主体的物理层通信协议,提高了信道的利用率,抑制了码间干扰,为构建电源监控系统打下了良好的基础。     

Torrefaction of pine in a bench-scale screw conveyor reactor

Numerous works are reported in the literature regarding the torrefaction of biomass in batch processes. However, in industrial applications, continuous reactors and processes may by more interesting as this allows for the integration of continuous mass and heat flows. To shed light on the operation of continuous torrefaction processes, this work presents the findings of continuous, bench-scale (2.5 kg h⁻¹) torrefaction experiments using pine wood particles as a feed material in a screw conveyor reactor. The shifts in product mass yields were in line with theoretical expectations for changes in reactor temperature and reactor residence times whereas the degree of filling within the screw reactor and the flow of the nitrogen purge gas were found to be negligible. The process allowed for the measurement of the particle surface temperatures throughout the length of the reactor and significant temperature differences where measured between the wall of the reactor and the reactor screw. The proximate composition and the higher heating value of the torrefied biomass were found to be correlated to the ratio of the mass of dry biomass feed to the mass of the torrefied biomass produced. Important observations regarding the operability of such a process, also relevant to larger-scale processes, include the need to prevent the occurrence of torrefaction vapour condensation (which leaves the torrefaction reactor in the form of a saturated vapour) in the presence of fine, solid particles as this leads to rapid particle agglomeration and process blockage.     

Development of moment-rotation model equations for flush end-plate connections

This paper presents the development of Ramberg-Osgood and Three-Parameter Power model prediction equations for the moment-rotation (M-θ) behavior of flush end-plate connections with one row of bolts below tension and compression flanges. A finite element model (FEM) of the connection region along with the connected beam and column is developed for load deformation analyses, which included material, geometric, and contact nonlinearities. The FEM model was verified with test results conducted and reported for flush end-plate connections in the literature during the 1980s. A matrix of test cases was obtained by varying the geometric variables of flush end-plate connections within their practical ranges. The connection M-θ data for these test cases were obtained by FEM analyses, which were then curve fitted to Ramberg-Osgood and Three-Parameter Power model equations to obtain parameters defining these equations. Finally, prediction equations were developed for parameters of the model equations as functions of geometric variables of the flush end-plate connections.     

景观设计的人文要素概念初探

在了解人文概念的基础上，文章确立了景观设计的人文要素概念，以及景观设计概念与文明进程，并对其在景观设计中的地位和意义进行了阐明，进而理顺景观设计的人文要素与其他要素的关系是十分必要的。     

评马里奥·博塔1980～1990年的城市建筑设计

通过对建筑自身价值及功能意义的深刻理解,博塔以综合、联结的方式表达了对城市关联的主张。     

Development and validation of a numerical model for buckling of coped beams

The lateral torsional buckling resistance of a beam depends on the support conditions. In structures for buildings, coped beams are often used. A numerical model is developed to investigate the influence of copes on the lateral buckling resistance. The model was verified with laboratory tests. This paper describes the background of the numerical model, the test program and the results of the validation. In a companion paper [Maljaars J, Stark JWB, Steenbergen HMGM, Abspoel R. Lateral-torsional buckling resistance of coped beams. Journal of Constructional Steel Research 2005;61(11):1559-75], the results of a parameter study are presented.     

The modelling of an embossed steel-to-cement paste confined interface loaded in shear

This paper presents experimental and theoretical research that was conducted in order to investigate and model the behaviour of interfaces between embossed steel plates and cement paste loaded in compression and shear. Special attention was paid to the relationships between the maximum shear stress, normal stress, cement paste resistance and embossment geometry. The slip-uplift behaviour was also investigated and shown to highly influence the shear resistance when the uplift movement is restricted by confining boundary conditions. When loaded in compression, these interfaces are able to transfer high shear forces with low slip and can therefore be used in structural applications such as, for example, connections between steel beams and concrete slabs in composite beams for bridges and buildings.     

寻找交接点--盐城师范学院图书情报中心设计

对旧建筑进行改造、加建，使旧建筑筑与新建筑通过一种创造性的方式结合在一起，具有非常现实的意义和巨大的价值。该文试国通过盐城师范学院图书情报中心的设计探索，讨论在原有校园肌理和新校园规划轴网叠合的基础上，积极寻求新老建筑优化交接的可能性，以简洁理性的方式最大限度的适应环境制约，创造独特的藏阅空间。     

Performance and suitability assessment of controlled islanding methods for online WAMPAC application

Controlled islanding can be used as an efficient action to prevent catastrophic blackouts. It splits a power system into a group of stable islands, according to an islanding solution that has been generated using an islanding method. A detailed understanding of these methods is a sound basis for the development of feasible controlled islanding methods for future networks. In this paper three methods (a) Ordered Binary Decision Diagram, (b) Weak Connection and (c) Spectral Clustering, are selected as typical islanding methods. The paper presents an analysis of their essential differences and their potential suitability for use as part of a practical implementation of controlled islanding. They are critically assessed and contrasted in terms of the objective function, graph model, solving algorithm and time complexity. The key difference between these methods is the nature of the objective function used: minimal power imbalance, minimal dynamic coupling or minimal power-flow disruption. A different objective function may require a different graph model and a different solution algorithm, which may result in the islanding methods having different time complexities and produce different islanding boundaries for the same network. Each method is applied to the IEEE 118-bus system to explore their strengths and weaknesses. Criteria for the selection of a suitable, practical method are discussed, as is the feasibility of Controlled Islanding as a WAMPAC application.