用于恶劣环境的耐高温压力传感器

为了解决如高温200℃等恶劣环境下的压力测量问题,基于微机电系统(MEMS)和高能氧离子注入(SIMOX)技术,研制了一种量程为0~120 kPa的压阻式压力传感器。该传感器芯片由硅基底、薄层二氧化硅、惠斯登电桥结构的硼离子注入层、氮化硅应力匹配层、钛-铂-金梁式引线层和由湿法刻蚀形成的空腔组成。在氧剂量1.4×10¹⁸/cm²和注入能量200 keV条件下,由高能氧离子注入技术形成厚度为367 nm的埋层二氧化硅层,从而将上部测量电路层和硅基底隔离开,解决了漏电流问题,使得传感器芯片可以在高温200 ℃以上的环境下使用。为了提高传感器在宽温度范围内的稳定性,对温度补偿工艺进行了研究,补偿后的传感器灵敏度温度系数和零位温度系数很容易控制在1×10^-4/℃·FS。实验标定结果表明:在200 ℃下,研发的耐高温压力传感器具有很好的工作性能,其线性度误差达0.12%FS、重复性误差为0.1%FS、迟滞误差为0.12%FS,精度达0.197%FS,满足油井、风洞、汽车和石化工业等现代工业的应用需求。     

Wear reducing effects and temperature dependence of tribolayer formation in harsh environment

Certain materials show a tribolayer formation especially at enhanced temperatures in abrasive environment, building a wear protection layer with the abrasive on the surface. Three materials with different microstructures were tested in three-body abrasive and impact/abrasive environments at temperatures up to 700 °C to investigate tribolayer formation. Optical and electron microscopical methods were used for wear qualification. Furthermore, hot hardness tests were performed up to 700 °C to investigate the influence of hardness drop on tribolayer formation.It was shown that no significant tribolayer formation occurs on grey cast iron, whereas other materials form tribolayers. Generally, tribolayer formation increases with increasing testing temperature, especially for austenitic and ferritic materials. This entails a self-protecting effect and thus superior wear resistance in abrasive environment.     

Novel method for characterizing relativistic electron beams in a harsh laser-plasma environment

Particle pulses generated by laser-plasma interaction are characterized by ultrashort duration, high particle density, and sometimes a very strong accompanying electromagnetic pulse (EMP). Therefore, beam diagnostics different from those known from classical particle accelerators such as synchrotrons or linacs are required. Easy to use single-shot techniques are favored, which must be insensitive towards the EMP and associated stray light of all frequencies, taking into account the comparably low repetition rates and which, at the same time, allow for usage in very space-limited environments. Various measurement techniques are discussed here, and a space-saving method to determine several important properties of laser-generated electron bunches simultaneously is presented. The method is based on experimental results of electron-sensitive imaging plate stacks and combines these with Monte Carlo-type ray-tracing calculations, yielding a comprehensive picture of the properties of particle beams. The total charge, the energy spectrum, and the divergence can be derived simultaneously for a single bunch.     

CPLD在飞行体加速度测试系统中的应用

本文论述的是一种应用于飞行体入水过载加速度测试系统.该研究选用Xilinx公司的可编程器件,详细介绍了该测试系统的组成和工作原理,着重介绍了控制电路的功能和工作时序仿真图.     

A testing device for rolling–sliding behavior in harsh environments: the twin-disk cryotribometer

Understanding the mechanical behavior of angular contact ball bearing contacts in extremely harsh environments has led to the development of specialized apparatus. This device simulates the rolling–sliding behavior of elliptical contacts where the dynamic and kinematic conditions are perfectly controlled. Such a device facilitates several types of analyses: that of mechanically induced surface damage, that of transfer film, that of characterizing surface treatments and surface coatings, and that of thermal phenomena at the contact. Moreover the testing device allows the experimental confirmation of theoretical models developed for determining bearing lifetimes. First we shall describe the testing device end afterwards we shall present results for each type of analysis mentioned above.     

Measuring the flow and the turbulence in a harsh environment using a modified Mc Caffrey gauge

Considering that many laboratory measurement techniques devoted to fluid mechanics are difficult to implement in field, especially for combustion and explosions, the present authors developed during the last 2 decades, a special type of Mc Caffrey gauges to measure the flow and the turbulence in those harsh situations (Fig. 1). Especially a fully embedded version is now under development and the initial work about this innovation is evoked.In this paper, the theory underpinning this technique is presented together with some technical details. Limitations are given and comparisons with reference techniques (hot wire in air jets) are presented.     

冲击加速度测试法在强夯实时检测中的应用

强夯法具有施工简单、效果好、费用低等优点,在多种地基土和各类工程,尤其大面积地基处理的工程中应用强夯法的优势很显著.目前,强夯施工时一般依据强夯技术规程采用测量夯沉量的方法来实时检测夯实程度.首先介绍了几种不同实时测量夯沉量的方法以及利用强夯冲击时夯锤的加速度或土的受力变换来实时检测夯实程度的方法.然后,通过实验发现加速度的峰值和作用时间与夯沉量有着非常紧密的关系.峰值的变化规律基本和累积夯沉量保持一致,作用时间的变换和单次夯沉量的变化类似.最后,提出了利用MEMS加速度传感器和无线芯片作为加速度采集系统的新方法.     

用于极端和特殊条件下机械传动误差检测的寄生式时栅研究

针对高速、重载、超大等极端条件和中空、狭窄、限重等一些不能安装普通传感器的特殊条件下的全闭环精密测量与精密控制问题,沿袭前期时栅传感器研究基础,提出一种将被测齿轮与传感器融汇一体的新方法.采用非接触、密封的离散测头线圈直接把被测齿轮、蜗轮、蜗杆、齿条、丝杠等当作均匀分度的“齿栅”,作为新检测方法的行波产生器件,再用时钟脉冲作为位移精密测量的基准.另外采用4对径离散测头消除除去4n(n=1,2,3,…)次以外的各次谐波误差,保证寄生式时栅动态的位移测量精度,并从理论和实验上证明了该方法的正确性和有效性.这种寄生式时栅具有体积小、重量轻、成本低、抗强振动和抗强污染等显著特色,应用前景广泛.     

Radio-frequency plasma transducer for use in harsh environments

We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer, eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0-5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.