硅基热电堆真空传感器的耦合场分析

利用商业化的1．2μm标准CMOS生产流水线,配合无掩模体硅各向异性腐蚀工艺,制造了一种热电堆型真空传感器,器件敏感部分尺寸为124um×100μm,由5层薄膜组成,最大厚度为3．2μm．采用一种简化方式对传感器建立有限元模型．新模型一方面忽略了气体对流和热辐射的传热作用,另一方面将各层介质和热电堆结构层分别进行了合并．模型具有简单的断面结构,网格划分容易,收敛速度快．运用ANSYS软件对模型进行了电一热、热一电耦合场分析,直接得到了1．5v加热电压驱动时不同压强下的热电堆输出电压,并与0．1～200Pa之间的测试结果进行比较,结果表明,采用简化建模方式的计算结果与测试结果之间的偏差小于6％．     

基于MEMS热电堆传感器的高温测量技术

为了拓宽MEMS热电堆传感器的温度测量范围,实现高温测量,根据MEMS热电堆传感器的原理,设计完成了A2TPM1334型MEMS热电堆传感器静、动态标定装置.通过试验得到标定结果;同时提供了基于MEMS热电堆传感器实现瞬态高温测试的技术方案及实现手段,并对其关键部分一红外衰减片性能进行了分析和讨论.     

压阻变换压力传感器的性能预测模型

热、压环境下压阻变换压力传感器的性能可以通过有限元方法预测．这里研究了简化的1／8模型，模型考虑了二氧化硅和氮化硅生成过程及堆阳极键合和胶粘结合过程．结果发现有限元预测结果和实验数据具有可比性．范例研究表明，硼硅堆导致产生一定的非线性，但它隔离了硬环氧树脂的非线性．在包装过程中最好使用柔性环氧黏合或软黏胶性结合．黏合材料的黏弹性和黏塑性将会导致传感器输出的滞后和漂移误差．然而，在相对稳定的环境下。软黏合剂对传感器的影响可以忽略．此外，详细的设计和过程信息有助于提高模型的适用性．     

MEMS热电堆高温测试系统中的MEMS传感器动态性能测试

传感器作为整个系统的核心部件,其性能对整个系统的指标起至关重要的作用,尤其是动态特性的优劣直接决定能不能测试到瞬态温度的变化。本文针对MEMS热电堆高温测试系统选定的A2TPMI型热电堆传感器进行静、动态性能标定,目的是为整个高温测试系统提供比较精确的传感器参数,为整个高温测试系统的校准提供理论依据。     

原子层热电堆热(光)电探测器的原理及研究现状

概述了基于晶体的各向异性Seebeck效应的原子层热电堆热(光)电探测器的基本原理和优点,并从材料体系的选择和器件的主要应用等方面阐述了该类型探测器的国内外研究现状,预测了原子层热电堆探测器在新材料、材料维度和新热源探索等的发展方向。     

基于塞贝克效应的半导体气敏传感器的研制

利用塞贝克效应研制成功ZnO半导体气敏传感器。这种新型传感器能够输出0-100mV的直流电压,对于信号的放大与处理将十分方便。在实验中对20×10-6NO2气体进行检测,结果表明:传感器的输出电压(温差电动势),随着待测气体浓度而变化。因此,利用温差电效应制作气敏传感器是一条完全可行的新思路。     

侧壁压阻式力传感器的研制与标定

在对现有微操作中夹持力问题进行分析的基础上,提出了一种基于面内侧壁压阻的力传感器加工方法,成功地在MEMS微夹持器上集成了压阻式的力检测传感器,对夹持力的检测反馈实现了微操作的闭环控制.该方法利用离子注入工艺和深度反应离子刻蚀（DRIE）工艺相结合制作检测梁侧壁压阻,改善了侧壁压阻工艺与其他工艺间的兼容性问题.最后通过压电叠堆驱动平台结合精密电子秤对压阻传感器进行了标定.测试表明,这种微力传感器加工技术可以很好地与其他工艺相兼容,力传感器的灵敏度优于72V/N,分辨率优于3μN.     

纤毛式MEMS矢量水声传感器的仿生组装

提出了一种纤毛式微机电系统（MEMS）矢量水声传感器的仿生组装技术.期望结合MEMS工艺和仿生组装工艺技术,解决复杂结构的仿生制造问题.文中简单介绍了仿生学理论以及定向探测机理.采用MEMS基硅微机械加工技术完成了传感器微结构的加工.通过模仿鱼类侧线器官神经丘感觉器的仿生结构,完成了传感器仿生微结构的组装,制作出纤毛式硅微仿生矢量水声传感器的模型样机.最后,完成了传感器的校准测试.测试结果表明,该水声传感器不但体积小、质量轻、结构简单,而且具有“8”字型的指向特性.该水声传感器的声压灵敏度为-197.7 dB（0 dB=1 V/μPa）.     

不同衬底条件对MEMS压阻传感器性能的影响

为了研究不同衬底条件对MEMS压阻传感器性能的影响,采用3种掺杂条件的衬底进行实验测试．在各步骤热过程后,对3种衬底条件下压阻区、引出区和保护框的方块电阻进行了测量和分析．通过对各部分方块电阻的测量可以看出,对于压阻区（P^-区）,A#和B#的方块电阻在开始注入扩散时相差很小,而由于注入杂质在高温下进一步扩散,衬底掺杂浓度对扩散后杂质分布的影响加大,方块电阻在后续的热过程中差别增大．通过比较不同衬底条件下各个热过程后的压阻数据,发现在3种掺杂条件中,20～40Ω·cm的衬底最符合预期压阻的设计．此结论已用于指导实际产品生产．     

基于MEMS技术的SU-8胶被动微阀片的设计与研制

为解决微流体在微流控芯片上的单向流动,进而实现生化反应的片上系统,采用微机电系统（MEMS）技术加工出SU-8胶微型阀片．SU-8胶阀片具有弹性模量和弹性常数低、开启压力小、反向泄漏小、易于加工等特点．从理论上分析了不同厚度（10μm,15μm,20μm,25μm）的微型阀片在不同压力作用下的挠度和应力分布,在相同尺寸和压力下,SU-8微阀片的挠度与传统的硅阀片的挠度相比要大10倍左右．讨论了有阻尼作用下的谐振频率以及过流特性。可知阀臂和阀座的尺寸是影响阀片性能的主要因素．给出了加工工艺,测试了阀片的正反向过流性能,以水作为工作物质,得到3种厚度阀片的过流曲线,其最大正向流速达到7000μL／min．     

Thermal Conductivity of Opacified Powder Filler Materials for Vacuum Insulations1

The thermal conductivity of powder fillings for load-bearing vacuum insulations is investigated. Different opacifiers have been tested in mixtures with perlite powder, precipitated silica, and fumed silica. Using temperature-dependent thermal conductivity measurements, the radiative thermal conductivity and the solid conductivity of the powder samples are separated. Additionally, the influence of the pressure load on the solid conductivity is studied. The thermal conductivities of silica powders with added opacifier powders (carbon black, magnetite, silicon carbide, titanium dioxide) can be as low as 0.003 W·m^–1·K^–1 if the powder boards are pressed with moderate loads. The use of microporous silica powders as filler materials allows internal gas pressures even beyond 10 hPa with only a moderate increase of the overall conductivity.     

A New Pulse Hot Strip Sensor for Measuring Thermal Conductivity and Thermal Diffusivity of Solids

The pulse hot strip method is a newly developed dynamic method to measure the thermal conductivity and thermal diffusivity of solids. It is based on monitoring the temperature response of a sample to a very short heat pulse liberated by a strip heat source. The instrument's uncertainty is estimated to be less than 3% for both quantities.     

用于MEMS热敏传感器中绝热层的多孔硅性能研究

利用电化学方法制备了多孔硅,利用显微拉曼光谱法测量多孔硅样品的热导率和多孔硅中的残余应力,利用纳米压入测量仪测量多孔硅显微硬度与弹性模量.研究了多孔硅绝热性能和力学性能与微观结构的关系,认为通过控制制备条件可以得到绝热性能和力学性能满足MEMS热敏传感器结构性能要求的多孔硅.     

New Transient Hot-Bridge Sensor to Measure Thermal Conductivity, Thermal Diffusivity, and Volumetric Specific Heat

A high sensitivity thermoelectric sensor to measure all relevant thermal transport properties has been developed. This so-called transient hot bridge (THB) decidedly improves the state of the art for transient measurements of the thermal conductivity, thermal diffusivity, and volumetric specific heat. The new sensor is realized as a printed circuit foil of nickel between two polyimide sheets. Its layout consists of four identical strips arranged in parallel and connected for an equal-ratio Wheatstone bridge. At uniform temperature, the bridge is inherently balanced, i.e., no nulling is required prior to a run. An electric current makes the unequally spaced strips establish an inhomogeneous temperature profile that turns the bridge into an unbalanced condition. From then on, the THB produces an offset-free output signal of high sensitivity as a measure of the properties mentioned of the surrounding specimen. The signal is virtually free of thermal emf’s because no external bridge resistors are needed. Each single strip is meander-shaped to give it a higher resistivity and, additionally, segmented into a long and short part to compensate for the end effect. The THB closely meets the specific requirements of industry and research institutes for an easy to handle and accurate low cost sensor. As the key component of an instrument, it allows rapid thermal-conductivity measurements on solid and fluid specimens from 0.02 to 100 W· m⁻¹·K⁻¹ at temperatures up to 250°C. Measurements on some reference materials and thermal insulations are presented. These verify the preliminary estimated uncertainty of 2% in thermal conductivity.     

隔气结构膜对真空绝热板热工性能及使用寿命的影响

真空绝热板具有良好的绝热性能,为节能目的,尤其是建筑领域,提供行之有效的热屏障,但其使用寿命成为诸多研究人员、制造商和用户最为关心的关键问题。隔气结构是维持真空绝热板内真空度的重要组成元件,其性能对真空绝热板的热工性能和使用寿命影响甚大。采用试验的方法只能在有限的时间内对其使用寿命研究,理论预测其使用寿命尤为重要。文章研究了气体和水蒸汽通过隔气结构膜渗透到板内对其等效导热系数的影响,采用数值分析的方法建立了相应数学模型,选取了三种典型隔气结构膜,测试了其相关性能参数指标,对其制得的真空绝热板,理论分析了导热系数变化规律,并对其使用寿命进行了评估。     

气凝胶复合材料真空绝热板的热导率计算及优化

采用常压干燥和抽真空工艺制备了气凝胶复合材料真空绝热板,基于一维稳态导热建立了气凝胶复合材料真空绝热板热导率的理论计算模型,研究了气凝胶密度和纤维含量对热导率的影响。结果表明,气凝胶复合材料真空绝热板的热导率随着气凝胶密度的增大而增大,随着纤维含量的增大呈现先减小后增大的抛物线型趋势,因此在某一最优的纤维含量下气凝胶复合材料真空绝热板具有最小的热导率。当气体压力为1Pa、10~3 Pa和10~5 Pa,对应的纤维含量分别为7.3%、7.0%和2.5%(体积分数,下同)时,真空绝热板具有最小的热导率,分别为3.5mW·m~(-1)·K~(-1)、3.8mW·m~(-1)·K~(-1)和15.8mW·m~(-1)·K~(-1)。研究结果可用于指导气凝胶复合材料真空绝热板的设计与性能优化,促进气凝胶复合材料真空绝热板在建筑保温领域的应用。     

Die Kalibrierung von Wärmeleitungsvakuummetern. The Calibration of Thermal Conductivity Vacuum Gauges

In many applications in the rough and fine vacuum thermal conductivity gauges are utilized. In order to determine the accuracy of the measuring values modern quality assurance systems require a regular calibration. The calibration laboratory of the German Calibration Service (DKD) at VACUUBRAND GMBH + CO KG features calibration equipment and procedures to calibrate vacuum gauges in the pressure range from 10^‐3 to 1000 mbar. The measuring techniques and calibration procedures are explained for thermal conductivity gauges with digital readouts. Besides general information on the calibration, particularities on thermal conductivity gauges and their effects on the calibration procedure are pointed out. The meaning of measuring deviation and measuring uncertainty and the interpretation of the calibration certificate for the user are discussed.     

热式微小流量传感器温度场及信号提取分析

热式流量传感器由于其结构简单、没有机械运动部件等固有的优点,在微小流量测量领域具有明显优势.针对微小气体流量测量领域毛细取样管路及其内部气体流体,进行热力学、流体力学理论分析,配合信号处理电路的分析,提出了消除环境温度影响的电路方法,同时使用MATLAB语言,用数值计算方法,获得了气体流量与毛细取样管路温度场之间的关系...     

Measurements of the Thermal Conductivity of Molten Lead Using a New Transient Hot-Wire Sensor

The paper reports new measurements of the thermal conductivity of molten lead at temperatures from 600 to 750 K. The measurements have been carried out with an updated version of a modified transient hot-wire (THW) method, where the hot-wire sensor is embedded within an insulating substrate with a planar geometry. However, unlike previous sensors of the same type, the updated sensor works with the hot-wire divided into three thermally isolated parts. The operation of this sensor has been modeled theoretically using a finite-element (FE) analysis and has subsequently been confirmed by direct observation. The new sensor is demonstrated to have a higher sensitivity and a better signal-to-noise ratio than earlier sensors. Molten lead is used as the test fluid. It has the lowest thermal conductivity of any material we have yet studied. This allows us to probe the limits of our sensor system for the thermal conductivity of high-temperature melts. It is estimated that the uncertainty of the measurements is 3% over the temperature range studied. The results are used to examine the application of the Wiedemann–Franz (W-F) relationship.