太阳能热水器与建筑的有机结合

介绍了太阳能热水器与建筑设计的结合及其在未来建筑中的重要性。     

混凝土复合受扭构件的统一理论及承载能力设计方法

采用协调压力场 -变角空间桁架模型对复合受扭构件进行受力分析 ,建立了统一理论强度相关方程 ,并以此方程为基础 ,提出了新的复合受扭构件抗扭承载能力的设计公式     

双馈风电机组PWM整流器控制方法的研究

基于双馈风力发电机组在运行的过程中,随工况的变化,功率变换器应具有能量双向流动、交-直-交变换效率高、直流环节电压稳定等要求出发,以三相PWM电压型(VSR)整流器为基础,分析了PWM整流器的基本原理,并建立了在三相静止坐标系下的变换器数学模型,应用电压矢量定向控制技术,并采用电压电流双闭环控制模式以及SVPWM调制方法构建了功率变换器系统,通过Sim Power Systems和Simulink仿真实验,确认了所采用的控制方法可行,对直流环节电压有较好的稳定作用,可实现机网侧能量双向变换控制以及具有单位功率因数等特点。     

Mixed enrichment for the finite element method in heterogeneous media

Problems of multiple scales of interest or of locally nonsmooth solutions may often involve heterogeneous media. These problems are usually very demanding in terms of computations with the conventional finite element method. On the other hand, different enriched finite element methods such as the partition of unity, which proved to be very successful in treating similar problems, are developed and studied for homogeneous media. In this work, we present a new idea to extend the partition of unity finite element method to treat heterogeneous materials. The idea is studied in applications to wave scattering and heat transfer problems where significant advantages are noted over the standard finite element method. Although presented within the partition of unity context, the same enrichment idea can also be extended to other enriched methods to deal with heterogeneous materials. Copyright © 2014 John Wiley & Sons, Ltd.     

Novel basis functions for the partition of unity boundary element method for Helmholtz problems

The BEM is a popular technique for wave scattering problems given its inherent ability to deal with infinite domains. In the last decade, the partition of unity BEM, in which the approximation space is enriched with a linear combination of plane waves, has been developed; this significantly reduces the number of DOFs required per wavelength. It has been shown that the element ends are more susceptible to errors in the approximation than the mid‐element regions. In this paper, the authors propose that this is due to the use of a collocation approach in combination with a reduced order of continuity in the Lagrangian shape function component of the basis functions. It is demonstrated, using numerical examples, that choosing trigonometric shape functions, rather than classical polynomial shape functions (quadratic in this case), provides accuracy benefits. Collocation schemes are investigated; it is found that the somewhat arbitrary choice of collocating at equally spaced points about the surface of a scatterer is better than schemes based on the roots of polynomials or consideration of the Fock domain. Copyright © 2012 John Wiley & Sons, Ltd.     

基于局部模糊逻辑系统合成的一类非线性不确定系统自适应控制

通过使用从属于系统状态区域上开覆盖的单位分解,首先将若干个局部生成的模糊逻辑系统合成而产生一种函数逼近器,与通常的模糊逻辑系统相比较,这种逼近器不仅具有万能逼近性质,而且由于局部模糊逻辑系统具有较少规则而能够保持语言可解释性；然后,通过将适当的参数植入这种函数逼近器中,能够为某些非线性不确定系统设计自适应镇定控制器；最后,通过仿真例子验证了所提出方法的有效性.     

Moral psychology is relationship regulation: Moral motives for unity, hierarchy, equality, and proportionality.

Genuine moral disagreement exists and is widespread. To understand such disagreement, we must examine the basic kinds of social relationships people construct across cultures and the distinct moral obligations and prohibitions these relationships entail. We extend relational models theory (Fiske, 1991) to identify 4 fundamental and distinct moral motives. Unity is the motive to care for and support the integrity of in-groups by avoiding or eliminating threats of contamination and providing aid and protection based on need or empathic compassion. Hierarchy is the motive to respect rank in social groups where superiors are entitled to deference and respect but must also lead, guide, direct, and protect subordinates. Equality is the motive for balanced, in-kind reciprocity, equal treatment, equal say, and equal opportunity. Proportionality is the motive for rewards and punishments to be proportionate to merit, benefits to be calibrated to contributions, and judgments to be based on a utilitarian calculus of costs and benefits. The 4 moral motives are universal, but cultures, ideologies, and individuals differ in where they activate these motives and how they implement them. Unlike existing theories (Haidt, 2007; Hauser, 2006; Turiel, 1983), relationship regulation theory predicts that any action, including violence, unequal treatment, and “impure” acts, may be perceived as morally correct depending on the moral motive employed and how the relevant social relationship is construed. This approach facilitates clearer understanding of moral perspectives we disagree with and provides a template for how to influence moral motives and practices in the world. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Designing unity magnitude input shaping by using PWM technique

This paper proposes a method for reducing vibrations in flexible systems by using the input shaping. A new input shaper technique based on Pulse Width Modulation (PWM) is used to shape the input.Since unity magnitude (UM) input shaping is easy to implement and provides less control duration, it has been preferred for many application areas. An analytical solution to time locations of the UM shaper requires very complex mathematical expressions due to involving in dependent constraint equations. This paper presents a simple PWM based input shaping method. The proposed technique allows designing UM shapers without analytical solution especially for the shapers having higher order impulse sequence. The method requires only the estimated value of system natural frequency and damping ratio. Desired numbers of impulses can be obtained by comparing reference signal amplitude and carrier wave frequency of a PWM. Analysis and experimental results demonstrate the effectiveness of the proposed method.     

齿轮泵马达一体机理论研究

齿轮泵马达一体机是将齿轮泵和马达做成一体的一种新的液压系统,在泵和马达之间安装调速阀或者将马达设计成变量马达来控制马达的转速和旋转方向。通过改变中间壳体的形状改变输入轴和输出轴角度的变化。简要介绍了其工作原理并证明了其理论上的可行性,为泵马达一体机的设计和选用提供了理论依据。     

Z源并网逆变器的间接单周电流控制策略

针对直接电流控制方式需要较多的采样环节造成控制电路结构复杂,且控制精确度依赖于传感器精确度的缺点,提出一种无需电流采样环节的间接单周电流控制方式.以单相Z源并网逆变器为对象,建立其状态平均数学模型,以实现单位功率因数并网为控制目标推导占空比控制函数d(t),利用单周控制的思想,根据d(t)产生相应的开关驱动信号,从而控...