平面盘形凸轮轮廓曲线统一建模的研究

将从动件的直线往复移动和定点往复摆动用虚拟摆动统一表示,采用单参数包络曲线理论建立直动和摆动从动件平面盘形凸轮轮廓的统一数学表达式。根据统一的数学表达式可以开发出一套适合于各类平面盘形凸轮机构的CAD软件包。     

基于包络线和函数拟合的录波数据分析

提出了一种基于包络线和函数拟合来分析短路电流录波数据的实用算法.首先对短路电流录波波形取包络线,利用指数函数拟合,滤除衰减直流分量;然后对周期分量取包络线,通过指数函数拟合来分析短路电流衰减基波分量,最终实现对暂态短路电流基波分量有效值时域内的多分辨率观察与研究.     

Alternative branching rules for some nonconvex problems

Following Linderoth (A simplicial branch-and-bound algorithm for solving quadratically constrained quadratic programs, Math. Program. 103 (2005), pp. 251–282), in this paper we show how a preliminary theoretical analysis about the quality of convex and concave envelopes over different regions may suggest branching rules alternative to the traditional ones based on boxes. For two nonconvex problems (minimization of the sum of products of affine functions and maximization of the sum of ratios of affine functions, in both cases over polytopes), we show how the indications of the theoretical analysis lead to computational results which confirm the superiority of the alternative branching rules with respect to those based on boxes.     

Numerical assessing energy performance for building envelopes with phase change material

In hot climate, phase change material (PCM) can be incorporated into building envelopes to reduce heat gain through the building envelopes and therefore reduce its cooling demand. In this study, the energy performance of building envelopes integrated with PCM has been explored using a popular dynamic building performance simulation package, EnergyPlus, and the energy saving mechanism of PCM was investigated. The simulation results reflected that PCM could effectively help to reduce the building's annual energy consumption by 20.9% for Guangzhou, China. In addition, for the Guangzhou city, 27°C transition temperature, smaller thermal conductivity of roof, and higher amount of PCM can all help to improve the building's energy performance. Additionally, it is suggested that in real building development/retrofit projects, the selection of PCM needs to be based on both their thermal properties and the local climatic conditions of the building.     

Actualising (Overlooked) Material Capacities

An emphasis on material synthesis is not without its pitfalls and challenges. Here Branko Kolarevic , Professor and Chair in Integrated Design at the University of Calgary Faculty of Environmental Design, alerts us to the dangers of overlooking materials' shifting capacities, which are so often scale dependent, while also disregarding existing materials in favour of the new or novel. As the potential grows for material systems in buildings to become more adaptive and to harness automation, Kolarevic describes some exciting developments that are taking place in dynamic facade design, providing the much-heralded promise of an efficient use of ambient energy.     

既有居住建筑围护结构节能改造热工性能优化

既有建筑物窗墙比差异较大,在节能改造过程中窗墙比和窗的热工性能对保温层厚度的影响不可忽视。在《严寒和寒冷地区居住建筑节能设计标准》围护结构节能设计规定的基础上,提出围护结构等效传热系数限值,综合考虑朝向、窗墙比、窗户的类型等因素,建立了外墙保温层厚度计算模型和围护结构热工性能参数优化模型,并以徐州地区某既有住宅为例,验证了模型的可行性。     

分户计量供暖节能住宅户型修正研究

针对多层住宅中不同户型在耗热量上的差异，引入户型体形系数修正各户的计量用热量，以计算和实测方法分析了一栋节能住宅不同围护结构户型的能耗特点，发现山墙、屋面、地面造成的不同户型之间的耗热量差别小于传统建筑；使用面积大的住户山墙造成的户型间耗热量差别小于使用面积小的住户。     

海关集装箱检测用电子直线加速器聚焦线圈磁场设计与测试

介绍了在电子直线加速器粒子动力学基础上进行聚焦线圈轴向磁场的设计；利用ＬＩＮＥ－ＡＣＣ／ＰＣ程序模拟计算，给出了不同初始发射度情况下满足束流包络要求的各种聚焦磁场数据。对已经加工好的聚焦系统进行了磁场分布测量，并将实际磁场与理论计算进行了比较。上述工作为确定聚焦线圈的设计方案和加速器的出束实验提供了可靠、丰富的数据。     

Generalized Bode envelopes and generalized Nyquist theorem for analysis of uncertain systems

This work is concerned with analysis of uncertain control systems, with regard to clustering of poles inside a simple symmetric bounded contour. We present and use the generalized Bode envelopes, generalized Mikhailov theorem, and the generalized Nyquist theorem for the simultaneous analysis of stability and quality of transient response of uncertain systems. Our results allow one to determine the number of open‐ and closed‐loop poles inside the given symmetric simply connected contour, for the entire uncertain family. The proposed method is computationally efficient and appropriate for solving complex control analysis problems, as evidenced in the examples. Copyright © 2010 John Wiley & Sons, Ltd.     

Focused ion beam (FIB) etching to investigate aluminium-coated polymer laminates subjected to heat and moisture loads

Multilayered aluminium-coated polymer laminates are the common barrier envelopes of vacuum insulation panels used as high performance thermal insulation in building applications. These laminates are made of up to ten distinct layers including three aluminium barrier layers applied by vacuum web coating. During their expected lifetime, which is required to last longer than 20 years, they will be subjected to heat and moisture loads induced by internal and external climatic conditions. This paper investigates the deteriorations of the barrier function of two different laminates commonly used for the production of vacuum insulation panels. These were subjected to well defined exterior heat and moisture loads and investigated by means of focused ion beam etching. Delamination of the polyurethane adhesive layers and stress induced relaxation in them are made visible. Oxidised aluminium layers are also detected by this method.