自然循环加热段内对流传热特性的实验研究

本文以常压去离子水为工质,对自然循环工况下上升加热段内单相水的对流传热特性进行了实验研究。实验结果表明,自然循环工况下上升加热段内工质的物性变化及由浮升力引起的自由流动对对流传热特性有重要影响。通过分析,提出了计算自然循环工况下上升加热段内单相水的对流换热系数的经验关系式。     

Four-channel coarse WDM for inter- and intra-satellite optical communications

A polymer volume grating-based four-channel coarse wavelength division multiplexer (WDM) for inter- and intra-satellite optical communication application is reported for the first time. This compact four-channel WDM device working at 0.83, 1.06, 1.34 and 1.55 μm is designed to build a complete optical link between two satellites, where wavelengths of 0.83 and 1.55 μm are used for data stream channels, 1.06 and 1.34 μm are used for inter- and intra-satellite connection. It is for the first time reported that a WDM device can cover such a large wavelength range in a single substrate. For transverse electric (TE) wave, the channel efficiencies at 0.83, 1.06, 1.34 and 1.55 μm are 55%, 40%, 35% and 45%, respectively. Channel efficiencies for transverse magnetic (TM) waves are 20% lower than those of TE waves on average. Wavelength shifts due to Doppler effect, temperature variations and radiation effects in space can be adequately accommodated.     

流动注射化学发光法测定盐酸曲普利啶

在碱性溶液中,N-氯代丁二酰亚胺可以氧化二氯荧光素产生化学发光。盐酸曲普利啶的存在可以显著地增强这一反应的化学发光信号。基于此,结合流动注射技术,优化了实验条件,建立了测定盐酸曲普利啶的流动注射化学发光新方法。该方法测定盐酸曲普利啶的线性范围1.0×10^-9—1.0×10^-7g/mL,检出限为5.0×10^-10g/mL。对浓度为7.0×10^-9g/mL盐酸曲普利啶溶液进行11次平行测定的相对标准偏差为4.1%。该方法已用于药物制剂中盐酸曲普利啶的含量测定,结果令人满意。     

湍流模型对风力机叶片气动性能预估的影响

本文采用计算流体力学软件Fluent,选取单方程Spalart-Allmaras模型、两方程低雷诺数k-ε模型和SSTk-ω模型等不同湍流模型,对NREL Phase VI风洞测试风力机的无偏航工况进行CFD模拟.通过将数值计算结果与相应的实验数据进行比较,发现在叶片表面为附着流时三种湍流模型数值模拟的结果都与实验数据吻合得很好,而在失速情况下两方程湍流模型的表现要优于单方程模型,其中以SST k-ω模型对截面压力分布、转矩等的预测更加准确.     

氟化钡晶体电注入着色临界温度及光谱特性

利用用自行研制的电注入实验装置,对氟化钡晶体进行电注入并使之有效着色. 由基本理论得到氟化钡晶体电注入临界温度,着色氟化钡晶体产生大量F和FA色心. 研究结果表明,经电注入氟化钡晶体,F色心首先在阴极附近产生,而且室温下F色心很不稳定.     

振动合成在气垫导轨上的验证

晶格中原子的集体振动——声子与晶格的热力学性质密切相关。它是凝聚态物理中的重要内容并具有广泛的应用。由于介绍量子化的声子需要较多的基础知识,目前很少在本科教学中展示该内容。本文从经典物理的角度出发,通过气垫导轨实验来演示滑块的集体振荡,验证了任一种振动均是由基振动线性叠加而成,这一实验在本科教学中可帮助学生理解"合成、叠加、耦合"等现代物理学概念。     

测定不同形状物体空气阻力系数的实验

设计空气流速连续可调的小型风洞,对圆形平板、圆柱体、流线体的空气阻力系数进行测量.利用U型管中水柱的高度差表达孔板法中空气的流速,通过悬臂梁力传感器测量测试物受到的空气阻力,根据空气阻力和U型管中水柱的高度差的关系测定空气阻力系数.     

基于手机摄像头的可见光寻书导航系统

针对在大型图书馆内寻书难的问题设计了一种基于手机摄像头的可见光寻书导航系统,该系统将LED可见光通信技术应用于图书馆内寻书导航中,并创新性的采用手机摄像头为LED可见光通信技术的接收端。配合使用自主设计的手机寻书软件,可实现图书馆内精确定位和实时导航,有效解决了寻书难的问题。     

Admissible consensus and consensualization of high-order linear time-invariant singular swarm systems

Admissible consensus analysis and consensualizing controller design problems for high-order linear time-invariant singular swarm systems are investigated. Firstly, by projecting the state of a singular swarm system onto a consensus subspace and a complement consensus subspace, a necessary and sufficient condition for admissible consensus is presented in terms of linear matrix inequalities (LMIs). An approach to decrease the calculation complexity is proposed, by which only three LMIs independent of the number of agents need to be checked. Then, by using the changing variable method, sufficient conditions for admissible consensualization are shown. An explicit expression of the consensus function is given, and it is shown that the modes of the consensus function can be arbitrarily placed if each agent is R$R$-controllable and impulse controllable and the interaction topology has a spanning tree. Finally, theoretical results are applied to deal with cooperative control problems of multi-agent supporting systems.     

电动效应作用下微通道内粒子运动的数值模拟

本文采用有限体积法数值模拟了轴向方波电场和直流电场作用下,具有不同电泳淌度粒子的运动情况.结果表明,在半个方波电场周期内,具有不同电泳淌度的粒子在相同的时间内达到各自的稳定速度,周期变化的方波电场使微粒子在微通道内做往复的运动;在直流电场作用下,两个不同电泳淌度的粒子会在轴向方向上产生位移差.定义从溶液中分离粒子的最短距离与微通道高度的比值为分离效率,数值模拟结果表明,分离效率随横向电场强度和粒子电泳淌度的增加而减小.