共查询到19条相似文献,搜索用时 140 毫秒
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兰州物理研究所研制了一系列真空标准装置,可用于真空规、方向规、分压力质谱计、真空漏孔和正压漏孔的校准.其静态膨胀法真空标准装置、动态流量法真空标准装置及超高/极高真空校准装置是用于真空规校准的三套基础标准,覆盖的校准范围为(10-10~105)Pa;程控式真空规校准装置适用于工业部门,其校准范围为(10-4~105)Pa;为实现质谱计的校准,研制了一台具有三路相同独立进样系统的分压力质谱计校准装置,标准分压力通过磁悬浮转子规以两种不同的方法进行测量,该校准装置可实现(10-7~10-1)Pa范围内的分压力校准;为实现真空漏孔的校准,研制了恒压式气体微流量标准装置和固定流导法气体微流量标准装置.恒压式气体微流量标准装置的校准范围为(10-8>~10-2)Pa·m3/s,同定流导法气体微流量标准装置的校准范围为(10-10~10-5)Pa·m3/s,漏孔漏率的校准通过比较被校漏孔和标准气体微流量计在一台四极质谱计上引起示漏气体离子流的大小计算得到;为实现正压漏孔的校准,研制了一台正压漏孔校准装置,采用定容法和定量气体动态比较法对正压漏孔进行校准,校准范围为(5 × 10-5~10-1)Pa·m3/s;研制了一台定向流真空校准装置,实现对方向规的校准和非平衡态分子流的研究,装置的校准范围为(10-7~10-1)Pa. 相似文献
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固定流导法校准真空漏孔方法研究 总被引:1,自引:1,他引:1
固定流导法采用的是分压力测量技术,对质谱分析室的漏放气率的指标要求不高.通过实验得到四极质谱计的非线性引起的测量误差可达38%,在具体校准过程中能够很好调节稳压室中的气体压力,使通过小孔的气体流量与待校真空漏孔漏率非常接近,从而避免了四极质谱计的非线性影响.稳压室中的气体压力比较大,所以稳压室不需要特别严格的材料处理工艺,具体校准过程中也不需要彻底的烘烤出气就能得到纯净的单一气体.固定流导法校准真空漏孔的不确定度的评定值为2.6%,可以通过精确校准电容薄膜规和控制温度来进一步降低漏孔校准的不确定度. 相似文献
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With careful sampling system design and in-situ calibration, Residual Gas Analyzers (RGAs) are becoming an important tool for quantitative Gas Analysis. RGAs were previously thought of as only “cheap and dirty” qualitative instruments for detecting leaks and/or contaminants in vacuum systems. This paper presents design features of RGA sampling systems which should be considered when specifying or building a mass spectrometer sampling system. Important design features are described including non-fractionating, fast time response sampling system design, onboard calibration standards, multiple sample points and remote operation. PC control of both the sampling system and the RGA provides for important features including automatic peak position tuning, spectrum de-convolution, composition analysis based on actual calibration gas standards, and automatic round-robin sampling and data logging. Applications of such integrated sampling systems currently operating at industrial and government facilities performing continuous on-line monitoring and self calibration are also described. All mass spectrometer/RGA sampling systems consist of the same basic subsystems including high vacuum pump/fore pump combination, the mass analyzer instrument including sensor head, control electronics and display, sample inlet valves and flow restrictions, and possibly a sample withdrawal/roughing pump. Although the basics of the system are the same, the finer details of sampling system design are frequently ignored, which make the simpler, less expensive sampling systems inadequate for quantitative gas analysis. Some of these important details which should be considered when writing a specification for a mass spectrometer sampling system are reviewed here. 相似文献
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疲劳试验机的动态力修正量与试验机参振质量、刚度及其分布、试验机的传感器安装位置有关。通过对传感器安装在2种不同位置的疲劳试验机力学模型的动态力分析,给出试验机使用时动态力的近似修正公式。通过动态力与参振系统质量分布的分析,结合频率在1000Hz以下动态法与静态法力值校准的实验数据,认为疲劳试验机检定时采用静态法力值校准较动态法力值校准更为合理。 相似文献
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对一种压电晶体力传感器动态标定系统进行了研究。首先介绍了这种动态力传感器标定系统的原理和构成;然后用区间算法分析了标定系统的精度,推导出了标定精度的具体表达式;最后对标定系统进行了大量的实验研究,比较了对标准质量块进行有悬挂和无悬挂安装两种实验方案的效果,研究了系统附加质量随频率变化的特性以及其他安装过程对标定结果的影响。研究表明:有悬挂安装法的一致性较差,对实验结果影响较大,无悬挂安装法的一致性较好;在中低频段,系统的附加质量变化幅度很小,力传感器的灵敏度也较为稳定,在高频段,系统的附加质量随标定频率的增加有显著增加,力传感器的灵敏度也有一定增大。这表明,在较高频带上进行实验时,力传感器的灵敏度有必要进行适当修正。 相似文献
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激光干涉法进行正弦力校准研究 总被引:5,自引:0,他引:5
采用绝对法进行正弦力校准,动态力由安装在振动台上的质量块产生,力值根据力的定义直接溯源到质量、加速度和时间。为了减少测量不确定度,质量块上的加速度分布必须进行准确测量。文中介绍了采用激光干涉法进行动态力校准的原理和信号处理方法,同时介绍了与德国PTB加速度实验室进行加速度测量的比对情况。结果表明,采用所介绍的正弦力校准方法可以提高校准的准确度。 相似文献
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《Chemometrics and Intelligent Laboratory Systems》1987,1(4):321-334
The low resolution mass spectra of a set of 78 toxic, volatile organic compounds, the presence of which is routinely monitored in ambient air samples, were examined for information concerning chemical classes and compound identification. The mass spectra were converted to their autocorrelation spectra, and the transformed spectra were studied using pattern recognition techniques. The inherent structure of the data showed three major classes: nonhaloaromatics, chlorocarbons, and bromo- and bromochlorocarbons. Principal components models, with dimensionality obtained with a cross-validation technique, contained two or three dimensions. Classification accuracy for the training set compounds was high. A hierarchical classification scheme, using statistical pattern recognition and k-nearest neighbor methods, was developed for chemical class assignment and for compound identification from mass spectral data files. The method was applied to gas chromatography—mass spectral data of known compounds of calibration sets obtained on the air quality monitoring mass spectrometer. Classification accuracy as to chemical class was 87% and compound identification accuracy was 84% for the calibration data. A classification scheme, which could be the basis for a microcomputer based expert system for mass spectral interpretation, is described. 相似文献
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KF Poulter 《Vacuum》1973,23(4):131-132
This paper describes how a mass spectrometer head and ion current amplifier system which has been calibrated as a partial pressure gauge in the high vacuum region, may have that calibration extended so that it can be used in the ultrahigh vacuum region. The technique is based on the measurement of the isotope ratio of the calibration gas. The paper also reports on the application of this technique to a particular instrument. 相似文献