Experimental observation on a small-scale thermoacoustic prime mover

INTRODUCTION In the past 30 years, much progress has been achieved in thermoacoustic research (Backhaus and Swift, 1999; Garrett et al., 1993; Zhou and Matsubara,1998). However, most of them were still at laboratory scale. Aiming for industrial applications, recent re-searches began to pay attention to larger or smaller scale systems. The problem of heat dissipation from miniature high-tech products (say ICs, MEMS) at-tracts more attention due to the higher heat flux ac-companying th…     

Impact of load impedance on the performance of a thermoacoustic system employing acoustic pressure amplifier

An acoustic pressure amplifier （APA） is capable of improving the match between a thermoacoustic engine and a load by elevating pressure ratio and acoustic power output. A standing-wave thermoacoustic engine driving a resistance- and-compliance （RC） load through an APA was simulated with linear thermoacoustics to study the impact of load impedance on the performance of the thermoacoustic system. Based on the simulation results, analysis focuses on the distribution of pressure amplitude and velocity amplitude in APA with an RC load of diverse acoustic resistances and compliance impedances. Variation of operating parameters, including pressure ratio, acoustic power, hot end temperature of stack, etc., versus impedance of the RC load is presented and analyzed according to the abovementioned distribution. A verifying experiment has been performed, which indicates that the simulation can roughly predict the system operation in the fundamental-frequency mode.     

用TiNi合金环作耗能元件的被动减振装置性能评价

设计了应用TiNi形状记忆合金环作耗能元件的被动减振装置,并对装置的力学和减振性能进行了初步评价.对加载和卸载过程中力-位移曲线进行了研究,当不对环水平方向的变形进行约束时,力-位移曲线为近似于直线且接近重合的2条曲线;若应用滑块对环水平方向的变形进行约束,在力-位移曲线上能形成滞回环,且随位移增加变得更饱满.滞回环的加载和卸载部分不与横坐标平行,而是2条斜线,装置受力时的这种变形特点,可提高装置的抗过载能力.增加环的数量,在相同位移时装置的耗能量明显增加.     

管道减振技术中的孔板压力降公式及其应用

在石油、化工等工矿企业,广泛使用管道输送流体.在一定压力和流速的作用下,这些管道壁上均会产生流体压力.当脉动的气流沿管道输送时,遇到弯头、异径管、盲板、气阀等元件时将产生激振力,受此激振力的作用,管道将会产生振动.压力脉动是引起管道及其附属设备振动的主要原因.而压力脉动是由于气流的脉动引起的,所以,控制压力脉动主要是消减气流的脉动.本文通过流体力学的柏努利公式推导出加孔板后的压力降公式.     

Analysis on stiffness and damping performance of active magnetic bearing system

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高校学风建设保证体系探究

高校学风彰显学校精神,反映办学理念和办学水平,体现学校品格。构建学风建设保证体系是保证高校学风达到预期目标的有效机制保障,也是高校思想政治教育、学生事务管理知识体系的重要内容。运用系统和集成的思想研究高校学风建设保证体系,建立一套严密、协调、高效的全方位的管理体系,持续改进,从而使高校学风建设制度化、标准化、规范化。     

悬链摆低雷诺数下的衰减振动研究

我们在低雷诺数（Re≤10）条件下建立了悬链摆的振动方程并求解,讨论了该条件下振动模式的衰减特点,解释了相关的物理现象。     

直线及平面工艺尺寸链解算浅析

工艺尺寸链的解算是制定工艺的基础。解算尺寸链应从封闭环的确定、组成环的查找入手。准确画出尺寸链线图，根据工艺尺寸链的类型．利用尺寸链的基本计算公式计算出有关工序尺寸及公差。     

建筑装饰材料及检测专业的办学特色研究

主要概述建筑装饰材料及检测专业在一年多的办学过程中,围绕市场需求,广泛吸收省内优质教育资源,逐步构建了教学与实践的平台,在课程建设、教学方法建设、教材建设、实验实训基地建设等方面取得了积极的成效.     

平面闭折线的环数及其求法

本文在文献 [1]的基础上 ,对平面闭折线的环数概念作了更精细的刻划 ,并给出了计算环数的“保角分离变换”方法     

基于ADAMS的杠杆夹紧器的仿真与分析

基于ADAMS虚拟样机仿真软件平台,对拟设计的一种钢厂用杠杆夹紧器进行了建模仿真及运动学和动力学分析,得到了杠杆夹紧器工作下的运动曲线及夹紧力曲线,并比较了有阻尼和无阻尼情况下的夹紧力及连杆的速度、加速度,为夹紧器的进一步优化设计提供了参考。     

美军自学与函授教育的特点及启示

美军自学与函授教育有专门的管理机构,制度落实高效;严把质量,突出为军服务;经费投人充足,技术先进,保障完善;军民结合,实施市场化和福利化;培训对象和范围广泛,形式灵活多样。借鉴美军经验改善我军的自学与函授教育必须做到：高度重视,加强开发管理;完善制度,提高质量;加大投人,改进手段,丰富形式。     

马克思主义经典作家安全思想特质的当代解读

马克思主义经典作家从生命个体、人的发展以及人与自然的关系三个维度解析了人类生存发展的安全特性。安全首先表现为以人的自然生存为前提的生命个体的存在,生命个体在自然界的生存安全体现了安全的自然属性;安全表现为以人的社会发展为目标的全面而自由的发展和人类自然生存的社会延续,其体现了安全的社会属性;安全本质上是人与自然关系的和谐统一。这些安全思想实际上为当代人类化解生态危机与生存发展困境提供了一把钥匙。     

基于花鼓灯的特质及现状的思考

以花鼓灯为研究对象,采用了文献资料法、专家访谈法、田野调查法、录像解析法等多种研究方法,从分析花鼓灯的特质入手,在阐述影响花鼓灯发展因素的基础上,对花鼓灯的传承与发展进行思考,期望为我国优秀传统文化的弘扬与发展献计献策。     

Wikipedia and the University,a case study

This article discusses the use of Wikipedia by academics and students for learning and teaching activities at Liverpool Hope University. Hope has distinctive aspects but we consider the findings to be indicative of Wikipedia use at other British universities. First we discuss general issues of Wikipedia use within the university. Second, we examine existing research on Wikipedia use amongst students and academics. Based upon a sample of 133 academics and 1222 students, our principal findings were: (1) 75% of academics and students use Wikipedia; (2) student use is typically confined to the initial stages of assessments; (3) a quarter of academics provide guidance on how to use Wikipedia and (4) 70% of academics use Wikipedia for background information for teaching purposes, something that it is not influenced by whether student use is tolerated or not. Our conclusion is that whilst Wikipedia is now unofficially integrated into universities, it is not ‘the’ information resource as feared by many and that an enlightened minority of academics have attempted to assimilate it into their teaching.     

Behavioral control and resiliency in the onset of alcohol and illicit drug use: a prospective study from preschool to adolescence

The developmental trajectories of behavioral control and resiliency from early childhood to adolescence and their effects on early onset of substance use were examined. Behavioral control is the tendency to express or contain one's impulses and behaviors. Resiliency is the ability to adapt flexibly one's characteristic level of control in response to the environment. Study participants were 514 children of alcoholics and matched controls from a longitudinal community sample (Time 1 age in years: M =4.32, SD =0.89). Children with slower rates of increase in behavioral control were more likely to use alcohol and other drugs in adolescence. Children with higher initial levels of resiliency were less likely to begin using alcohol.     

少年儿童网络信息行为特征与引导研究

通过系统分析网络环境下少年儿童的网络行为特征,必须联合家庭、学校和以少儿图书馆为代表的社会机构,加强对少儿网络行为的正向引导。     

试论儿童舞蹈艺术特性与心理特征的关系

儿童舞蹈是儿童内心世界的反映。它与成人舞蹈在艺术特征方面有重大差异，有其独特的艺术特征。在儿童舞蹈的编排及教学中，必须结合儿童的心理特征，把握好儿童舞蹈艺术特性与心理特性的关系，将童趣性、游乐性和童幻性统一起来。     

高校仪器设备管理计算机系统的开、闭环控制设计

高校仪器设备管理计算机系统利用信息传递回路可开、闭控制的设计方法,解决了系统各数据类关系组成结构问题,实现了网络环境下经费、计划、合同、仪器设备管理过程动态闭环及非网络环境下各业务工作站独立开展工作的两种运行机制.该系统着重在其功能实现程度、操作灵活性、可维护性、数据资源共享性、各业务子系统间的业务协调性等方面进行了设计与实现,提高了系统的安全可靠性.     

论影视的审美特征

本文探讨了影视的审美特征 ,认为 ,从审美心理学的角度看 ,影视艺术具有声画可溶性、时空自由性、形象逼真性、表现综合性等审美特征