一种硅/二氧化硅双层微悬臂梁温度传感器

利用IC工艺和微机械加工技术制作了一种硅／二氧化硅双层微悬臂梁温度传感器。基于硅和二氧化硅两种材料热膨胀系数的差异，不同温度下梁的挠度不同，其形变可通过位于梁根部的压敏电桥检测。理论计算和实验结果表明：压敏电桥输出电压与温度成线性关系。对器件结构进行了优化设计，实验探索了提高传感器测量重复性的时效处理工艺。该温度传感器可用于瞬态温度的测量。     

A bi-material microcantilever temperature sensor based on optical readout

As one of the simplest MEMS sensors, microcantilever can sense temperature faster and more sensitively than traditional thermometers as its small size and low thermal mass. In this paper, an Au/SiNx bi-material microcantilever temperature sensor based on optical readout is presented. The deflection of the cantilever varies with the change of temperature due to the differences in thermal expansion coefficients between gold and silicon nitride. Then, the temperature could be accurately measured by detecting the deflection of the cantilever with optical lever method. By experiments, the theoretical model is verified and the temperature characteristics of the sensor are also determined. With a commercial microcantilever, the temperature resolution of the sensor is tested to be 0.02 K when 25 mm length of optical arm set. By optimizing the microcantilever parameters, the temperature resolution of the sensor could be 0.1 mK. High sensitivity makes it suitable for some special precise temperature measurements.     

SAW谐振器型温度传感器

本文介绍一种用于通讯的ＳＡＷ谐振滤波器及相关电路所构成的ＳＡＷ谐振器型温度传感制的原理和特性，与ＳＡＷ延迟线振荡器型温度传感器相比，它具有频率高、插入损耗小、带宽窄、旁瓣抑制大等突出优点，实测结果表明：ＳＡＷ谐振器型温度传感器的短期频率稳定性大于１０＾－７，其灵敏度为－０．６ｋＨｚ／℃，具有良好的线性度和重复性，可用于高精度的温度测量。     

独特谐振模式下薄膜体声波谐振器的设计

计算了四层复合结构的薄膜体声波谐振器(FBAR)的输入阻抗谱,各层采用的材料分别是Al/AlN/Al/Si,其尺寸为0.8 μm/1.9 μm/0.8 μm/100 μm,得出其有效机电耦合系数k²_eff随谐振模式的分布情况,从而得到最大k²_eff的独特谐振模式在1~2 GHz为第40阶谐振模式。从理论上探讨了各层的尺寸及材料属性对该独特谐振模式及其频移的影响,以及串联谐振品质因数FOM等滤波器设计的主要性能参数在该模式下的分布情况。实验结果表明,工作在独特谐振模式下的FBAR的性能依赖于各层材料尺寸,当压电层厚度从0.2 μm变到4.3 μm时,特殊谐振模式频率从1.2 GHz增加到4.8 GHz;当基底厚度变厚时,有效机电耦合系数从3.2%变到0.8%,串联品质因数从2 000变到700;而电极变厚后,有效机电耦合系数趋于一个稳定值。这些数据在实际设计过程中对滤波器的微调具有参考意义。     

Sputtered Si-containing low-friction carbon coatings for elevated temperatures

This work presents a tribological study on three sputtered amorphous carbon-based coatings containing Si and Cr (a-C, a-C:Cr and a-C:Si). Molecular dynamics simulations predict tetrahedral bonds between C and Si in the a-C matrix. Ball-on-disk-tests against Al₂O₃ carried out at room temperature revealed a coefficient of friction of 0.08–0.1 for all films. Between 250 and 325 °C, Si decreases the COF and wear rate to $<0.05$ and $<5\times {10}^{-17}{\mathrm{m}}^3/\mathrm{N}\times \mathrm{laps}$, respectively. The a-C reference shows a COF of 0.15±0.05 and a wear rate of $1\times {10}^{-16}{\mathrm{m}}^3/\mathrm{N}\times \mathrm{laps}$, whereas the a-C:Cr film failed. The improved tribological performance of a-C:Si expands its application temperature to 450 °C and is most probably related to formation of Si-compounds on the film surface, as evidenced by X-ray photoelectron spectroscopy.     

A modified micromechanical approach to determine flow stress of work materials experiencing complex deformation histories in manufacturing processes

Work materials experience a broad range of strains, strain rates, and temperatures in many manufacturing processes such as machining, forming, etc. Strain rate has an important effect on the yield and flow stress of work materials, especially metals, since at higher strain rates there is less time for thermally activated events; consequently, it is equivalent to a lowering of the temperature of the materials. On the other hand, it is also true that, for high strain rate deformations such as metal cutting, adiabatic plastic flow may produce significant temperature changes in the materials. Flow stress is significantly affected by the strain rate history; hence, mechanical behavior may not be fully described in terms of a mechanical equation of state relating the instantaneous stress, strain, strain rate, and temperature.Based on the concept of dislocation mechanics, a micromechanical approach with the new concept of temperature coefficient has been explored to overcome the model issues such as negative or constant flow stress above the critical temperatures. The flow stresses of aluminum 6061-T6 and titanium Ti-6Al-4V have been predicted, for the first time, using the modified micromechanical model based on the available baseline high strain rates test data. The constitutive model was further modified and extended to predict flow stress below as well as above the critical temperature. The corresponding model predictions were compared with the experimental data, attaining good agreement.     

分子印迹型薄膜体声波谐振毒品检测传感器

针对毒品探测的需求,对高灵敏度、高选择性及可工作于液相环境中的传感器进行了研究,利用分子印迹技术(MIT),结合薄膜体声波谐振器(FBAR)和微流体(micro fluidics)技术构造了新型传感器.首先,阐述了用分子印迹技术制作FBAR吸附层材料的原理,利用分子印迹技术制备了对特定毒品分子具有专一吸附性的印迹材料,将其作为吸附层涂覆在基于微机电系统(MEMS)及微流体技术的FBAR上.根据压电方程和运动学方程推导出了FBAR压电振子的等效电路及电学端口输入阻抗公式,构建了以AIN为压电材料的微流体结构FBAR毒品检测传感器模型.对该结构的FBAR传感器进行了理论研究和公式推导,并在理论模型的基础上进行了仿真实验,得到了单位面积质量响度达0.8pg/Hz·cm2的FBAR传感器.得到的实验结果远高于石英晶体微天平这一传统的质量敏感型传感器,可实现对溶液中毒品分子的快速检测.     

T形铠装铂电阻传感器

本文叙述了在涤纶、锦纶等化纤生产中应用的Ｔ形铠装铂电阻传感器的结构、性能、加工及使用情况等。     

航天相机主镜热特性研究

研究了某航天相机的热特性,计算了该主镜在特定温度载荷下的温度分布,求解了该主镜的面型变化及达到热平衡的时间;同时对计算结果进行了分析;结合光学设计提出的要求,根据计算结果给出了主镜的温度水平和温度梯度变化范围指标,并提出了主镜热控设计的初步设想。     

A new type of temperature-based sensor for monitoring of bridge scour

This paper introduces a sensor measuring the scour depth around the bridge based on the theory of heat conduction. The heat dissipation rate is different in different, heat losses faster in water environment than that in soil environment. Therefore, the position of mud surface can be judged by measuring the temperature change of the sensor in underwater environment. The sensor consists of a stainless steel cuboid shell, a heating piece and two probes of temperature sensor. The continuous power supply to the heating piece can make it heated, and the temperature statistics of two probes of temperature sensor is continuously measured during this process. Meanwhile, the temperature time-history curve in different environment can be drawn. The quantitative indicators K_e and R² using for judging environment can be obtained by fitting the curve. The environment can be judged according to the environment coefficient K_e and the coefficient of determination R². Also, the scour depth can be obtained. The laboratory experiment has proved that this sensor can distinguish environments such as air, flowing air, soil, sand, mud, water and flowing water.     

浅谈总装车间保温箱设计及应用

针对总装车间保温箱制作不统一情况,规定了保温箱的材料、规格选型、加热方式、控制方式以及整体布局等,提高保温效率,保证产品装配质量。     

多功能异辛氧基硼酸钐的性能研究

试验结果表明 ,异辛氧基硼酸钐添加剂使 5 0 0SN基础油的承载能力得到明显改善 ,其抗磨性能明显提高 ,摩擦系数明显降低 ,且在 5 0 0N时的摩擦系数较 30 0N时更低 ;还具有良好的抗腐蚀性能、优良的氧化安定性和热稳定性     

A Potentiometric Method of Detecting Moving Boundaries in the Determination of Transference Numbers

SUMMARY

A new method is described by which transference numbers for both leading and following ions can be determined in a moving boundary experiment. The boundary is detected by the change in potential accompanying its passage into the volume between two microprobes sealed into the moving boundary tube. With the aid of a volume calibration, the transference number of the leading ion can thereby be determined. A method of measuring ionic mobilities directly is described in which the same microprobes are used to measure both the potential gradient and the boundary velocity. Transference numbers for the following ion can also be measured by the indirect method, which makes use of the Kohlrausch relationship. The microprobes are used in this case to measure the conductance ratio between leading and following solutions. The detector is described in detail along with a suitable power supply. A sheared cell is introduced in which the boundary is formed initially with the aid of a pipet and a flowing system. The apparatus is tested thoroughly on systems whose transference numbers are known.     

高弹性气动双锥体离合器的热负荷研究

对高弹性气动双锥体离合器的热负荷问题进行了理论分析和研究,建立了相应的物理及数学模型。通过编制的软件,分析了可能影响动态温度场、应力场的影响因素。本研究将对高弹性气动双锥体离合器的动态设计及优化选型提供理论依据。     

Pr激光表面合金化对Ti－6A1－4V组织热稳定性的影响

采用激光Ｐｒ合金化处理，研究了Ｔｉ－６Ａ１－４Ｖ稀土合金化快速凝固组织对热稳定性的影响。结果表明，Ｔｉ－６Ａ１－４Ｖ激光表面Ｐｒ合金化可提高其在７００℃以下的热稳定性，这是由于快速凝固过程获得的组织在高温下具有良好的抗粗化能力。ＴＥＭ分析表明，经Ｐｒ合金化的钛合金表层内形成一种含Ｐｒ的有序固溶体相，该相具有六方结构，ａ＝０．３９１４ｎｍ，ｃ＝０．６５９２ｎｍ，ｃ／ａ＝１．６８４，呈椭圆或圆形颗粒状，分布于初生β柱晶的亚胞胞壁，尺寸约０．１～０．４μｍ。在退火过程中还形成一种析出相，分布于位错线及小角晶界上，尺寸为１０～２０ｎｍ，分析了这两种析出相对组织热稳定性的积极作用。     

薄膜的力学测试技术

对薄膜力学性能的测试方法、技术以及所取得的主要成果进行简要的综合介绍。     

新型热作模具钢CH95的热稳定性能研究

从热作模具钢在６５０℃和７００℃时效过程中的硬度变化和组织变化来探讨其热稳定性能。研究结果表明，新型热作模具钢ＣＨ９５钢的热稳定性能明显优于Ｈ１１。     

Thermal displacement error compensation in temperature domain

Thermal displacement errors are becoming more and more important in the precision engineering field where the specifications are ever increasing. This paper proposes a novel technique to compensate in-plane thermal displacement errors in a thin plate under a moving disturbance heat load. The displacement error is evaluated at the point of the moving heat load. The technique utilizes Thermal Modal Analysis (TMA) as a means to analyze the transient temperature distribution in the plate and estimate the thermal displacement field resulting from that temperature field. The temperature field is controlled by applying additional heat loads to the plate to control and eliminate some of the modes in the temperature domain which have the largest influence to the thermal displacement error. The theory of thermal modal analysis and the developed technique of controlling modes in the temperature domain are explained. The experimental setup and results are shown to validate the control of the thermal modes.     

滚动轴承温度场研究的现状和展望

高速滚动轴承的温升及温度分布状态直接影响着主轴—轴承系统的工作性能和使用寿命。滚动轴承转速的不断提高,则会导致轴承摩擦生热急剧增加,如果热量得不到及时有效地散发,轴承内部的温度将会异常升高。温度过高则会导致轴承内部零件表面灼伤甚至相互胶合、咬死而早期报废,后果十分严重。因此,随着主轴—轴承系统转速的不断提高,滚动轴承内部的温升及温度分布已经成为需要考虑的重要指标。我们对高速滚动轴承的发热机理、传热过程及温度分布三个方面分别进行了深入地分析和探讨;详细阐述了国内外学者对轴承热分析研究的现状及存在的主要问题;并对未来滚动轴承温度场的研究进行了展望。     

纯滚动集中接触润滑入口区热效应的数值分析

在对入口区膜厚形状和压力分布的简化处理前提下，采用数值分析方法全面地分析了纯滚动集中接触润滑入口区的热效应，得到了的结论与其它学者的试验及分析结果较为一致。