边缘构件刚度对索网结构风振响应的影响分析

本文根据索网结构中索系和边缘支承结构共同工作且相互影响的特点,运用随机振动理论,考虑风的三维相干性,讨论了脉动风作用下,边缘构件刚度对索网结构的自振频率和风振响应的影响规律。分析表明,临界刚度比是索网结构动力响应计算的一个关键参数。     

高比例风电接入下次同步振荡监测系统次同步相量监测装置多阶段优化配置方法

随着风电等新能源大规模接入,未来次同步振荡问题将更为突出,亟需建立新型次同步振荡监测系统。中国学者已针对次同步振荡监测装置——次同步相量监测装置(subsynchronous phasor measurement unit, SPMU)开展了相关研究。在此基础上,如何经济高效地制定SPMU配置方案成为了构建次同步振荡监测系统的首要问题。基于风电机组频率耦合阻抗模型提出计及评价指标之间重要程度差异、振荡工况发生概率的监测关键度评价体系;考虑到SPMU实际安装配置中常存在多阶段安装的情况,建立计及节点监测关键度的SPMU多阶段优化配置模型;最后利用整数线性规划求解多阶段优化配置方案。采用美国得克萨斯州ERCOT系统、改进的New England 39节点系统,验证了所提指标及算法的准确性和经济性。     

边坡非圆临界滑面确定之动态规划法研究

临界滑面的确定一直是边坡稳定性研究的关键,而边坡临界滑面一般为非圆型式,目前国内外还未能满意地解决非圆临界滑面的确定问题。基于Ｊａｎｂｕ法,利用动态规划理论成功地解决了非圆临界滑面的确定及相应安全系数的求算问题。该方法可以考虑地下水及地震对边坡稳定性的影响,尤其对于复杂地质条件边坡稳定性分析,与目前国内外同类方法相比具有非常明显的优越性,完善了边坡临界滑面确定之理论。     

Challenging industry conceptions with provotypes

Design researchers have an important role to play when engaged with user-driven design projects in industry. Design researchers can craft ethnographic material to facilitate transfers of user-knowledge to industry, and demonstrate how this material can be used in the design of new products and services. However, ethnographic findings can reveal issues that are in tension with conceptions of the project members from industry. Instead of brushing these tensions aside, we propose provotyping (provocative prototyping) as an approach to constructively build on them as a resource for change. Provotypes are ethnographically rooted, technically working, robust artefacts that deliberately challenge stakeholder conceptions by reifying and exposing tensions that surround a field of organisational interest. The daily and local experience of provotypes aims to stir dialectical processes of reflection on how conceptions currently are, and fuel the front end of a development process by speculating how conceptions could be different. In this article we start by making explicit the relation between provotypes, practices of critical design and organisational sense-making. We then illustrate, through a multi-stakeholder project concerning the field of indoor climate, how provotypes facilitate transfers of user knowledge to industry, and how they contribute to the development of new products and services. We end by framing the role of the design researcher and discuss the politics that are inherent to design provocations.     

Minireview: Methodology and instrumentation to evaluate critical pressure and temperature parameters

Critical parameters, such as critical temperatures, pressures, and densities, are basic in the development of supercritical fluid technology. However, the number of compounds for which critical parameters has been determined and has been limited by the current technology and the sensitivity of compound information to the external environment in a critical state. This paper provides an overview of the principles, key equipment, and methodologies to measure the critical parameters of compounds. The reliability of various determination methods is discussed, and future research into methods to determine critical compound parameters is suggested.     

直杆弹性稳定分析的加权残值法

系统地介绍了加权残值法在直杆弹性稳定分析中的应用．算例表明,此法简单易行,可用于等截面直杆,也可用于变截面直杆,不仅适用于手算,且可用于电算．     

适用于粗颗粒矿物浮选的颗粒悬浮特性的研究

在实验室条件下通过测定新型叶轮定子系统在不同转速条件下浮选槽内的颗粒悬浮参数,确定适用于粗颗粒矿物选别的完全离底悬浮临界转速,同时对新型叶轮定子系统和普通KYF叶轮定子系统在浮选槽内的矿物颗粒悬浮参数进行对比,分析得出新型叶轮定子系统上下两个循环通道的分界面到槽底的距离比普通KYF叶轮大,可以有效提高粗重颗粒的离底悬浮高度,在避免粗颗粒矿物快速沉降的同时可以提高其回收效果。     

乳品检验工作质量关键控制点

介绍了如何控制乳品检验工作关键点,确保检验工作质量,为质量控制、质量保证提供信息来源,从而提高产品质量。     

Individual Differences in Susceptibility to False Memory in the Deese-Roediger-McDermott Paradigm.

The authors addressed whether individual differences in the working memory capacity (WMC) of young adults influence susceptibility to false memories for nonpresented critical words in the Deese-Roediger-McDermott associative list paradigm. The results of 2 experiments indicated that individuals with greater WMC recalled fewer critical words than individuals with reduced WMC when participants were forewarned about the tendency of associative lists (e.g., bed, rest, . . .) to elicit illusory memories for critical words (e.g., sleep). In contrast, both high and low WMC participants used repeated study-test trials to reduce recall of critical words. These findings suggest that individual differences in WMC influence cognitive control and the ability to actively maintain task goals in the face of interfering information or habit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermodynamic investigation of thermoresponsive xanthan‐poly (N‐isopropylacrylamide) hydrogels

Polysaccharide‐based hydrogels, such as xanthan maleate/poly(N‐isopropylacrylamide) (PNIPAAm) interpenetrated polymer networks, are thermostimulable materials of interest for the controlled release of biologically active components due to conformation changes at the low critical‐solution temperature (LCST) PNIPAAm phase transition. The phase transition of these interpenetrated polymer network hydrogels, where PNIPAAm is in a ‘confined’ environment, was examined by high resolution magic angle spinning nuclear magnetic resonance and differential scanning calorimetry. High resolution magic angle spinning nuclear magnetic resonance spectroscopy allows the accurate determination of LCST and an evaluation of the corresponding thermodynamic data. More particularly, the evolution of these data as a function of the composition of the hydrogel, and of the external parameters such as pH and ionic strength, was considered. LCST shows a minimal value with increasing xanthan content. Moreover, it was possible to calculate, as a function of temperature, the fraction of NIPAAm which remains uncollapsed. The data obtained for pure PNIPAAm hydrogels are in good agreement with recently published results. The phase transition of PNIPAAm in a diphasic hydrogel is broader when PNIPAAm is ‘confined’ within an interpenetrated polymer network than in a pure PNIPAAm crosslinked network. The widening of the transition with increasing xanthan content indicates a reduction of the PNIPAAm interchain aggregation in a network structure. Copyright © 2011 Society of Chemical Industry