带有区间约束的产品设计参数模糊推理法及其在继电器智能设计中的应用

在产品设计规则和计算式中,常存在一些只能在某一范围内取值的待定系数(设为a,且a∈[aL,aH]).a的取值通常受到多种因素的影响和约束,而这种约束往往带有模糊性.为此,首先根据设计规则中各种影响因素对a的模糊约束关系,分别构造两者的备择集以及备择集元素在其论域上的模糊集合,然后基于模糊综合决策方法来确定a.本方法剔除了以往在解决这一问题时,由人来决定a取值的主观性,适用于产品的智能化设计.     

地环流抑制技术的探讨

文章在分析了地环流的形成和危害的基础上，讨论了接地、隔离、浮置等抑制地环流的措施，提出适用范围及注意事项，以求得最佳的抗干扰效果。     

端部约束对三轴排水剪试验影响的数值分析

针对三轴排水剪试验的端部约束问题,利用有限元软件ABAQUS模拟三轴排水剪试验,研究在不同的围压下,不同的端部约束条件对三轴排水剪试验软土剪切特性的影响。结果表明,端部完全光滑时,试样的整体应力应变关系能很好地代表材料本构模型;端部约束的存在导致了试样内部应力应变分布不均匀,约束程度越大,不均匀性越明显;小应变条件下,端部约束对于试样整体应力应变关系的影响并不大,而大应变条件下,端部约束的影响则不可忽视,约束程度不同影响程度一致。     

A revised examination of the dual pathway model for bulimic symptoms: The importance of social comparisons made on Facebook and sociotropy

ObjectiveTo replicate the Dual Pathway Model (DPM) of bulimia nervosa (BN) symptoms prospectively, and to assess whether a revised version of the DPM that included the variables social comparisons made on Facebook and sociotropy influenced the DPM.MethodParticipants were 245 females who completed baseline measures (T1) that assessed the DPM, as well as the constructs social comparisons made on Facebook, and sociotropy, and a follow-up questionnaire, which assessed symptoms of depression, bulimia, and dietary restraint, one month later (T2).ResultsPath analysis revealed that the original and the revised DPMs had excellent fit once modifications to the respective models were made. In both DPMs, T1 pressures to be thin and T1 thin ideal internalization were related to T1 body dissatisfaction. T1 body dissatisfaction prospectively predicted T2 depressive symptoms and T2 bulimic symptoms, but not T2 dietary restraint. Furthermore, T2 dietary restraint, but not T2 depressive symptoms, predicted T2 BN symptoms. Results also showed that T2 dietary restraint was associated with T2 depressive symptoms. In the revised DPM, T1 social comparisons made on Facebook were associated with T1 body dissatisfaction, T1 pressures to be thin, and T2 bulimic symptoms. T1 sociotropy was related to T1 social comparisons on Facebook, T1 pressures to be thin, T1 body dissatisfaction, and T2 bulimic symptoms.ConclusionsFindings suggest the BN preventative efforts might benefit from addressing appropriate forms of social comparisons, especially those made on Facebook, and the personality trait sociotropy.     

Experimental investigation of edge restraint on punching shear behaviour of RC slabs

Current codes of practice usually do not consider the effect of edge restraint on the punching shear capacity of flat plate type reinforced concrete structures. As the punching shear provisions incorporated in various codes of practice are a direct result of the empirical procedures, they do not usually provide an accurate estimation of the ultimate punching load capacity of a slab with its edges restrained against rotation. This is because no account is taken of the enhancement of punching capacity due to the in-plane restraint in many types of reinforced concrete slab systems. A total of 16 model slabs with restrained and unrestrained edges have been tested in an effort to ascertain the influence of boundary restraint, thickness of the slabs on their structural behaviour and punching load-carrying capacity. Edge restraint has been provided by means of edge beams of various dimensions in order to mimic the behaviour of continuous slabs. The cracking pattern and load-deflection behaviour of the slabs tested have also been monitored closely.     

基于PPP模式的公共部门投资激励约束机制方法研究

城市基础设施建设中采用 PPP 模式,是带动城市经济与社会双重效益的新特征。公私部门合作需要利用激励约束 机制来调动参与项目建设投资的积极性,以获得经济社会公益与经济效益共赢。通过对实践案例研究发现,有效建立激励机 制,取决于政府在项目建设中为私有部门提供的报酬及其为自身积极努力的程度。激励机制效用是政府独特约束控制权确定 的关键。为了论证研究方法在项目实施中的效用,构建了激励约束机制方法模型。研究结果表明,采用 PPP 模式的项目运 营决策标准存在差异性,激励约束机制在 PPP 项目运营中作用和风险分担能力最强,收益约束监管难度最高。因此,建立 激励约束机制便于规避 PPP 模式在城市建设运营中的风险且有利于促进社会公平。     

Experimental Research on Tank Exhaust's Thermal Restraint Based on Thermoelectric Generation Theory

Aimed at the high temperature of tank's exhaust, the principle of applying thermoelectric generation technology to tank thermal restraint was analyzed. Its application experiments were conducted to test the exhaust temperature under different rotating speeds, The experiment results show that the thermoelectric generator can output sufficient electric energy to drive fans; the external surface temperature of radiator is reduced by over 65.0% compared with exhaust surface due to the combination effect of thermoelectric conversion, fan cooling and heat radiation; the exhaust surface temperature rise caused by increase of the engine's rotating speed results in the increases of the temperature difference of the thermoelectric generator's cold and hot sides, the fan's driving voltage and heat convection, thus, the effect of fan's cooling is more obvious than that of the temperature rise caused by exhaust.     

汽车半主动乘员约束防护系统设计与动力学建模仿真

设计了一种汽车的半主动乘员约束防护系统,该系统能根据反应时间余量来判断车辆发生碰撞的可能性,不同的可能性对应不同的危险等级,当危险能避免时则发出警报提醒驾驶员主动避免,不能避免时提前启动乘员约束保护装置。通过仿真分析软件MADYMO建立了汽车正面碰撞模型,并经试验验证了其正确性。对所设计的安全带预紧装置与座椅坐垫倾角调整装置进行仿真,然后与传统的被动执行机构仿真结果进行对比。结果表明：半主动乘员防护系统可提前实现安全带预紧和座椅坐垫倾角的调整,相比传统的被动防护系统中碰撞后火药预紧与座椅坐垫倾角不变,乘员的头部、髋部伤害略有减小,颈部弯矩峰值、胸部加速度、胸部压缩量分别减小了20.6%、14.6%、15.6%。所设计的半主动约束防护系统能有效减轻乘员的损伤。     

2K-H型行星轮系优化设计系统的研究

以太阳轮和全部行星轮的体积之和最小为优化设计目标函数,以太阳轮的齿数、齿宽、模数、行星轮的个数为设计变量,以行星轮系的传动比条件、同心条件、装配条件、邻接条件、模数条件、最少齿数条件、强度条件为约束条件,建立了行星齿轮传动优化设计的数学模型。以穷举法为优化设计方法,以VisualBasic为编程工具,研制出了行星轮系的优化设计系统,该系统能自动完成2K-H型行星轮系的优化设计。     

机器人手端与外界作用时的控制

讨论了在机器人作业过程中手端与外界相互作用时,位置与力单独控制的有关问题,提出了它们的缺陷———实际的约束环境与给定的约束环境不符时,会出现控制的不确定现象。针对这一现象,提出了采用刚性控制可以较好地解决这一问题。