光反射法微摩擦测试仪

为研究MEMS的微摩擦需设计一种能够测量微米尺度样品摩擦特性的专用仪器,尤其是能进行微机构摩擦力和正压力测试的大范围、高灵敏度的微摩擦检测装置。给出了一种基于光反射法的微摩擦测试仪的设计方法,介绍了该仪器的设计原理、测力传感器的结构设计、仪器的标定方法。硅测力传感器采用MEMS工艺制作,具有变形量大、线性度好、灵敏度高等优点。实验结果表明,该测试仪能满足微机电系统微摩擦测试的需要。     

电子部科学技术进步奖专栏

磁头定位系统动态综合测试仪是一种基于计算机的仪器,采用了称之为“虚拟面版”的先进技术来实现波形实时显示和仪器直观操作。仪器对所有参数都实现了在线、实时的自动测量和数据自动处理,绘图、打印、显永、存档功能齐全,是研究开发和生产磁盘定位系统的理想测试设备。该仪器既能完     

液体表面张力激光快速测量法

基于插板法测液体表面张力系数的基本原理,介绍了一种利用半导体激光器及准直光学系统输出的矩形平行光束,结合线阵CCD传感器,实现液体表面张力系数快速测量的方法。通过测量激光束两边沿在液体表面的入射角来求得表面张力系数,解决了插板法测液体表面张力系数的液面上升高度和接触角检测难题,避免了人为因素的影响。推导了矩形激光束两边沿在液体弯月面的入射角与表面张力系数的关系,以及用CCD测量激光入射角的计算公式,并进行了参数设计和误差分析。结果表明:为了提高液体表面张力系数的测量精度,在满足测量条件下,应采用尽可能大的矩形激光束宽度、激光入射角和CCD相对距离。理论分析表明,当光束宽度的测量误差为5 μm时,水的表面张力系数测量精度为1%。若将光束宽度的测量误差减小到2 μm,则水的表面张力系数理论精度可达0.5%。实验结果证明了水的表面张力系数测量精度达到1%。     

微机化机构动态参数测试技术

机械传动机构作为机器产品的重要组成部分,要求有严格的质量保证,其中的动态性能指标是质量保证的基本要素。目前,企业大多采用传统的R-C电路测量或采用多个单功能仪器对各参数逐一检测,测试效率和测试自动化程度都比较低。我院研制的MEC-B型机械动态参数测试仪是国内一种新型的机械动态参数测试分析仪器,该测试仪以微处理器为中央处理单元,具有4路模拟传感器和4路数字传感器输入通道,可同步采样,自动输出数据及图形。主要测试参数有:线位移、线速度、     

土工布力学性能智能测试仪的研制

介绍了一种土工布力学性能测试仪的设计原理和方法。该测试仪可以完成土工布的各种力学性能测试试验，包括条样拉伸、握持拉伸、撕裂、CBR顶破、圆球顶破、刺破及厚度的测量。通过试样的实测结果和数据分析说明仪器符合土工布仪器设计要求，可以用于土工布力学性能的测试，具有较好的实用性。     

一种带有粘温转换功能的新型旋转粘度计的设计

为测得不同温度下和剪切率下的牛顿液体粘度,利用液体粘度与温度的关系,设计了一基于单筒旋转粘度计的带有粘温转换功能的新型旋转粘度计,解决了对于需要测得不同温度下的液体粘度的难题.该仪器以PIC18F877单片机为核心,利用定时/计数器(Timer0)模块进行角位移测量,通过程序中的粘温转换算法,实现了粘度测量和粘温转换功能.测试证明,该新型粘度计能够满足实际应用要求.     

SFX—1智能水质测试仪

该仪器是一种水质综合参数测试仪,能对水中的pH值、温度、溶解氧、钠离子、电导、氨氮比等多项参数进行精确测试。并直观地用数码管显示出来。由于该仪器采用     

振动弦黏度/密度测试仪的研制

根据振动弦法测量的原理,利用平行磁铁提供磁场,以钨丝为振动弦,设计了一套能够同时测量流体的黏度和密度的热物性测试装置,并且搭建了测试系统,编制了基于LabVIEW的数据采集程序以及基于L-M算法的非线性拟合方法.在此基础上,对振动弦测试仪的仪器参数进行了标定,为进一步开展相应的研究奠定了基础.     

粘度自动测试仪的研制

报道了一种粘度自动测试仪。介绍了仪器的工作原理。通过光电自动控制，并配以电子数字计时器，实现了测量自动化，测量精度比乌氏粘度计提高近一个数量级。给出了测量结果和应用实例。     

用于常温液体物性参数综合测试仪的单片机测控系统

研究和开发常温液体物性参数综合测试技术,对于液体产品质量评价及其生产过程控制具有重要意义。为此,介绍了一种用于液体黏度、密度、表面张力测定的单片机测控系统,该系统主要由微压差传感器、称重传感器、温度传感器、扭矩传感器、模拟信号放大器、单片机及其扩展电路和微型空压机组成,与相关机械装置相配合,可完成液体物性参数综合快速检测,且测试结果的准确性和重复性较好。文中介绍了系统硬件设计和软件设计方法。     

Temperature as sensitive monitor for efficiency of work in abrasive flow machining

Work efficiency is considered as most concerned target in abrasive flow machining (AFM). It has many influence factors, such as, temperature, media viscosity, abrasive hardness, particles sharpness and density, workpiece hardness, pressure, piston moving speed, etc. The influence of temperature on work efficiency is most critical. In this investigation, both commercial AFM equipment and test rig are used to carry out AFM experiments. AISI1080, 1045 and A36 steels are used as specimens in the tests. It has been shown from AFM tests that media viscosity decreases continuously with increasing temperature. Media temperature increases with increasing cycles, which means media viscosity decreases with cycles increasing. AFM tests shows that increasing cycles extensively decrease materials removal and surface roughness decreasing efficiency. When media with different viscosity is used media with high viscosity has more effective material removal efficiency. The high viscosity media to surface roughness improvement is also better than the low viscosity media at the initial several cycle numbers. With further increasing cycles the roughness improvement difference among different media with different viscosity is reduced. It is found from Mooney viscosity–temperature relation of media that temperature rising directly results in the decrease of media viscosity. When work cycles are increased the media temperature is quickly increased. The media viscosity is also decreased dramatically. In order to understand the mechanism of decrease of material removal efficiency with temperature, computational fluid dynamics (CFD) approach is applied to predict the abrasive particles movement tendency. A two-dimensional model is constructed for AFM process. The simulation results show that the temperature rising of media results in increasing the rolling tendency of abrasive particles which causes work efficiency deteriorated.     

A device for measuring the density and surface tension of melts

A method was developed and an experimental device was constructed for measuring the density and surface tension of melts. The hydrostatic method was used with the application of a volute-spring balance, which significantly simplified the device design. Its operation was tested by measuring the density and surface tension of a LiF melt in a temperature range of 1160–1350 K. The measurement errors are 1.5–2% and 10%, respectively.     

树脂超声处理的新型涂层技术研究

为提高快速成形系统中堆积方向的制作分辨率,研究了光敏树脂的黏度、表面张力及固液两相接触角随超声处理时间和功率的变化规律。试验结果表明:LPR2001型光敏树脂在超声处理开始的2~5min,树脂的黏度、表面张力及接触角迅速减小;随处理时间延长,以上树脂特性值随之回升;超声功率在40~50W时,树脂的黏度、表面张力及接触角减小幅度最大。对光敏树脂超声处理前后能实现的最小涂层厚度进行了实验对比,结果表明:超声处理的树脂能将最小涂层厚度由原来的0.02mm降低到0.01mm。     

The Effect of Laser Texturing of Steel Surfaces and Speed-Load Parameters on the Transition of Lubrication Regime from Boundary to Hydrodynamic

Laser surface texturing (LST) is an emerging, effective method for improving the tribological performance of friction units lubricated with oil. In LST technology, a pulsating laser beam is used to create thousands of arranged microdimples on a surface by a material ablation process. These dimples generate hydrodynamic pressure between oil-lubricated parallel sliding surfaces. The impact of LST on lubricating-regime transitions was investigated in this study. Tribological experiments were carried out on pin-on-disk test apparatus at sliding speeds that ranged from 0.15 to 0.75 m/s and nominal contact pressures that ranged from 0.16 to 1.6 MPa. Two types of oil with different viscosities (54.8 cSt and 124.7 cSt at 40°C) were evaluated as lubricants. Electrical resistance between flat-pin and laser-textured disks was used to determine the operating lubrication regime. The test results showed that laser texturing expanded the range of speed-load parameters for hydrodynamic lubrication. LST also reduced the measured friction coefficients of contacts that operated under the hydrodynamic regime. The beneficial effects of laser surface texturing are more pronounced at higher speeds and loads and with higher viscosity oil.     

添加剂对氨水表面张力影响的实验研究

利用滴重法测量了氨水溶液在添加剂正辛醇（1-Octanol）和异辛醇（2-EH）作用下的表面张力,该方法的测量误差在3％以内。测量结果显示：在氨水溶液中加入添加剂以后,其表面张力随着添加剂浓度的增加而减小,并最终达到一个稳定值;但是,和LiBr溶液不同,溶液表面气体侧的添加剂蒸汽对氨水溶液表面张力的影响并不明显;对于没有添加剂的氨水溶液,其表面张力随着氨水浓度的增大而近似线性降低;在添加剂作用下,当氨水浓度较低时,其表面张力随着氨水浓度的增加而增大,然而,当氨水浓度较高时,其表面张力随着氨水浓度的增大而降低。根据表面张力的测量结果,可以推测,在氨水浓度较低时,添加剂正辛醇和异辛醇会对氨水吸收过程中的传热传质起到强化作用。     

用光纤传感技术实现液体表面张力系数非接触测量

液体表面张力系数的测定对研究物体的性质有重要的意义。但传统的测量方法一般都具有操作复杂、速度慢、精度低等特点。为此,根据光干涉的基本原理,现提出一种利用光纤传感技术实现液体表面张力系数非接触测量的方法,并采用本测量系统对不同温度蒸馏水及20℃相同浓度的乙醇进行测量,实验结果比较理想。表明该方法不仅克服了传统方法的缺陷,而且具有实时、快速、高精度等特点。     

中间层液体的表面能对粘着行为中Pull-off力影响的实验研究

中间层液体膜存在的情况下,弯月面力(Cap illary Force)的作用使Pull-off力增加。中间层液体的表面能是影响弯月面力作用强度的重要因素之一。利用表面张力仪测量了1,2二氯丙烷、1,2乙二醇等5种液体的表面能,利用表面力仪测量了这5种液体作为中间层时Pull-off力的值。结果表明,在一定范围内,粘度相近液体量相同时,Pull-off力随表面能增加而增加;表面能相等时,Pull-off力随液体量增加而增加。     

Thermophysical properties of compressor oils for refrigerating plant

In the present study, an accurate experimental information for the widely used commercial refrigerating compressor oils ONF 46, ACD 100 FY, Azmol, FR 32, XC 15, XC 40 and WF 15A is presented. Experimental data on the capillary constant, surface tension, density, refractive index and kinematic viscosity at the temperature range from 293 to 353 K for seven commercial compressor oils are reported. In addition, the experimental data on the isobaric heat capacity at temperature range from 288 to 393 K, the vapor pressure at liquid‐saturated curve and average molecular weight for four commercial compressor oils are firstly presented in the paper. The data obtained are fitted by few‐constant correlations. Based on results obtained, the values of pseudocritical temperature for the compressor oils have been determined. Copyright © 2008 John Wiley & Sons, Ltd.     

Magnetic microrheometer for in situ characterization of coating viscosity

A magnetic microrheometer has been designed to characterize the local viscosity of liquid-applied coatings in situ during solidification. The apparatus includes NdFeB magnets mounted on computer-controlled micropositioners for the manipulation of ～1?μm diameter superparamagnetic particles in the coating. Magnetic field gradients at 20-70 T/m are generated by changing magnet size and the gap distance between the magnets. A specimen stage located between two magnets is outfitted with a heater and channels to control process conditions (temperature and air flow), and a digital optical microscope lens above the stage is used to monitor the probe particle position. Validation studies with glycerol and polyimide precursor solution showed that microrheometry results match traditional bulk rheometry within an error of 5%. The viscosities of polyvinyl alcohol (PVA) solution and polyimide precursor solution coatings were measured at different shear rates (0.01-5?s(-1)) by adjusting the magnetic field gradient. The effect of proximity to the substrate on the particle motion was characterized and compared with theoretical predictions. The magnetic microrheometer was used to characterize the time-viscosity profile of PVA coatings during drying at several temperatures. The viscosity range measured by the apparatus was 0.1-20?Pa?s during drying of coatings at temperatures between room temperature and 80?°C.     

EFFECT OF TENSILE STRESS AND RESIDUAL STRESS ON THE SPONTANEOUS STRAY FIELD SIGNALS FROM THE SURFACE OF 0.45%C STEEL

In order to explore the quantitative method of metal magnetic memory testing(MMMT) and clarify the relationship between Hp(y), the normal component of spontaneous stray field, and applied stress or residual stress, the static tensile tests of 0.45%C steel sheet specimens are carried out on a servo hydraulic MTS810 machine. Hp(y) values are measured during the test process by an EMS-2003 metal magnetic memory diagnostic apparatus and a non-magnetic electric control displacement instrument. Residual stresses of some points on the surface of a specimen are measured by a Stress Tech X-Stress 3000 X-ray diffraction instrument. The results show that the same variation rules of Hp(y) value versus applied tensile stress are presented under the different conditions of load-on and load-off. However, the same rule does not exist between the Hp(y) value and residual stress. The variation of Hp(y) value reflects the history of applied tensile stress.