载人密封舱微量有害气体检测与校准技术研究

空间载人密封舱由于材料出气、人体代谢等原因会释放微量有害气体。为保证舱内环境适合航天员工作和生活,必须对舱内微量有害气体成分及浓度进行检测。本文介绍了常用的微量气体检测方法,并采用质谱法建立了载人密封舱微量有害气体检测与校准地面测试系统,分析了舱内微量有害气体种类、碎片峰和图形系数,并进行了试验研究,研究结果可为载人密封舱微量有害气体检测及校准系统的在轨应用提供设计依据和优化参数。     

航天器密封舱压力模拟控制方法研究

带有密封舱段的航天器进行热平衡试验时,为了模拟空间微重力下的气体换热方式,需要对密封舱内的压力进行调节与控制。文章研究了航天器密封舱压力模拟控制的特征,根据这些特征,采用特殊的方法解决了真空低温环境下远距离真空压力柔性管道的密封与绝热、密封舱内压力准确测量、密封舱内压力连续控制与调节、密封舱内环境状况分析与监测、快速抽除与收集密封舱中大量沸点较高的可凝性蒸汽等难题,成功地对大型航天器密封舱在微重力状态下的气体换热情况进行了地面模拟,使密封舱内的仪器设备经受了考核。     

LZL-203型四极质谱计的相对灵敏度系数和图型系数

ＬＺＬ－２０３型四极质谱计是一种结构紧凑牢靠、参数固定、按键操作、性能稳定的小型四极质谱 计，除了能定量指示真空系统的总压强外，还适宜定量地分析真空系统内的残余气体。为此，我们考察 了仪器对质量范围内的主要几种气体的相对灵敏度系数和图型系数。     

危险气体监测系统的设计和研制

本文介绍我们设计和研制的“危险气体监测系统”。介绍了系统的设计和使用方法。本系统以四极质谱计和β放射线电离规作为传感器,质谱计的质量范围为1到100原子质量单位,它能从混合气体中检测出最小浓度为数ppm的气体组份,通过标定能定量分析微量的氢,氧、氮、氦、四氧化二氮、硝酸、偏二甲肼等。     

质谱技术在空间研究中的应用

空间成份测量的质谱计必须满足空间测量的特殊要求.空间质谱计在空间测量中目前主要用于空间诱导环境的污染检测、大气层及轨道的成份探测、生保系统中的大气监测.在第二部分对空间材料质谱进行了评价与分析.这方面的工作应包括污染物的成分鉴别、污染物来源的跟踪、空间材料污染的最低标准的制定.第三部分介绍了空间模拟和环境检测方面的工作.除此而外.还可以用于测量字航员在训练过程中氧耗量和二氧化碳生成量;宇航员呼出气和血液气体内的氧和二氧化碳进行动态监测.在空间站模拟器中.为了保证于航员在模拟器中的生命安全.必须用质谱计对模拟器内的气体进行监测和控制.在火箭研究中.利用质谱计对燃烧气体进行分析以寻求更合理的设计.     

四极质谱计的碎片离子图形系数

一、引言目前,四极质谱计已广泛地用于真空系统内残余气体分析。原则上,任何一种已校准的质谱计都能用来进行真空系统内气体组分的定量分析。这种校准通常包括两个方面:图形系数和灵敏度的校准。关键的问题是要取得图形系数的好的重复性。到目前为止,有关用四极质谱计作定量分析的报道是不多的,有关图形系数重现性的报道更为少见。根据工作原理和结构,四极质谱计的质量岐视比其它质谱计,如回旋质谱计、磁偏转质谱计更为严重。因此,四极质谱计的图形系数是和其它质谱计不同的。造成图形系数变化的原因除了离子源工作条件外,主要是边缘场和分析场的质量岐视。     

LZL-203型四极质谱计的结构特点和性能

LZL-203型四极质谱计是北京分析仪器厂最近研制成功(82年7月通过鉴定)的一种小型,多功能,操作简便,价格低廉的仪器,主要用于真空、电子、核物理等领域的科研实验室和工业生产部门,对压强低于1×10-4托的真空系统进行残余气体分析,(总)压强测量和检漏,是研究真空过程,获得清洁真空,保证产品质量的重要监测工具。 一、仪器结构 1.总机 LZL-203型四极质谱计由四极探头和电气部件两大部分组成。四极探头包括离子源、四极分析器和接收器等三个主要部分,由一个外径φ78mm的法兰支承,构成一整体结构。此法兰既作为与被测真空系统相联结的法兰,又…     

四极质谱计在超导托卡马克装置上的应用

四极质谱计广泛用于托卡马克装置上,用来监测聚变装置的真空品质,为真空系统的状态提供判断依据。本文介绍了四极质谱计在全超导非圆截面托卡马克装置(EAST)上的多种应用,为聚变装置的第一壁处理和聚变过程中多种残余气体成分含量变化提供数据。实验证明四极质谱计是EAST装置真空系统运行、等离子体与器壁相互作用研究过程中一种较为基础的测量工具。     

分流法真空漏孔校准装置不确定度的评定

分流法校准真空漏孔是通过四极质谱计比较气体流量计分流后的实用标准气体流量与被校真空标准漏孔产生的离子流获得校准值。主要介绍了分流法真空漏孔的校准方法、装置原理,对不确定度进行了分析,从气体流量计、分流比、四极质谱计等方面对真空漏孔校准装置的不确定度进行评定,提高了校准装置校准的可靠性。     

四极质谱计的真空系统与取样装置

一、基本要求 我厂现有的四极质谱计,是极杆长为180毫米,带有二次电子倍增器的较大型质谱计,适于实验室使用。质谱分析对象是各种电真空器件及材料中的气体。电真空器件的特点是体积较小(几厘米3到几升),内部气压较低( 10-8～10-7托、充气管除外),总气体量只有10-9～10-6托·升。20℃时,1托升克分子量为M的气体质量是: m20=5.470 × 10-5M·克(1) 假定器件内气体是空气(M=29),则气体质量为10-12～10-9克。要将这样微量的气体顺利引入质谱室进行较准确的分析是相当困难的,因为在气体取出,输运和分析过程中,极易遭受污染,甚至变得面目全非,…     

Numerical analysis and estimation of the statistical error of differential optical absorption spectroscopy measurements with least-squares methods

Differential optical absorption spectroscopy (DOAS) has become a widely used method to measure trace gases in the atmosphere. Their concentration is retrieved by a numerical analysis of the atmospheric absorption spectra, which often are a combination of overlapping absorption structures of several trace gases. A new analysis procedure was developed, modeling atmospheric spectra with the absorption structures of the individual trace gases, to determine their concentrations. The procedure also corrects differences in the wavelength-pixel mapping of these spectra. A new method to estimate the error of the concentrations considers the uncertainty of this correction and the influence of random residual structures in the absorption spectra.     

Highly sensitive optical waveguide sensor for SO2 and H2S detection in the parts-per-trillion regime using tetraaminophenyl porphyrin

ABSTRACT

Optical waveguide (OWG) sensors present great potential for detecting trace levels of harmful gases because of their high sensitivity and anti-electromagnetic interference. However, OWG-based SO2 and H2S-detecting sensors in the parts-per-trillion (ppt) range are still lacking. We fabricated 5,10,15,20-(tetra-4-aminophenyl) porphyrin (TAPP) thin film-based OWG sensor devices (TAPP-OWG) to detect SO2 and H2S gases, in which TAPP thin film was immobilized over the surface of a potassium ion exchange glass OWG. These sensors successfully measure extremely low concentrations of SO2 and H2S (detection limit?=?1 ppt), providing good repeatability for SO2 (10 ppt) and H2S (10 ppt) gases, with relative standard deviations of 1.67% and 3.68%, respectively. With fast response (t1) and recovery (t2) times for SO2 (t1=4 s, t2=157 s) and H2S (t1=2 s, t2=117 s) at room temperature, TAPP thin film enhances the potential of OWGs for use in high-sensitivity trace-level gas detection.     

Critical issues in trace gas biogeochemistry and global change

The atmospheric composition of trace gases and aerosols is determined by the emission of compounds from the marine and terrestrial biospheres, anthropogenic sources and their chemistry and deposition processes. Biogenic emissions depend upon physiological processes and climate, and the atmospheric chemistry is governed by climate and feedbacks involving greenhouse gases themselves. Understanding and predicting the biogeochemistry of trace gases in past, present and future climates therefore demands an interdisciplinary approach integrating across physiology, atmospheric chemistry, physics and meteorology. Here, we highlight critical issues raised by recent findings in all of these key areas to provide a framework for better understanding the past and possible future evolution of the atmosphere. Incorporating recent experimental and observational findings, especially the influence of CO2 on trace gas emissions from marine algae and terrestrial plants, into earth system models remains a major research priority. As we move towards this goal, archives of the concentration and isotopes of N2O and CH4 from polar ice cores extending back over 650,000 years will provide a valuable benchmark for evaluating such models. In the Pre-Quaternary, synthesis of theoretical modelling with geochemical and palaeontological evidence is also uncovering the roles played by trace gases in episodes of abrupt climatic warming and ozone depletion. Finally, observations and palaeorecords across a range of timescales allow assessment of the Earth's climate sensitivity, a metric influencing our ability to decide what constitutes 'dangerous' climate change.     

竖井型城市隧道自然通风模型实验研究

以连续竖井的静压分布特性为基础,采用分段模型实验方法,搭建了南京市某隧道模型,对正常交通状况下隧道交通风压进行实验,得到了隧道的自然通风特性及竖井通风的一般规律;建立了通风量与有害气体浓度之间关系的数学模型,研究了评价竖井对城市隧道自然通风效果影响的方法,并对该实际隧道通风效果做出评价,得出了竖井型城市隧道自然通风的相关结论,为此类城市隧道的设计及运营管理提供一定的参考。     

Tomographic multiaxis-differential optical absorption spectroscopy observations of Sun-illuminated targets: a technique providing well-defined absorption paths in the boundary layer

A novel experimental procedure to measure the near-surface distribution of atmospheric trace gases by using passive multiaxis differential absorption optical spectroscopy (MAX-DOAS) is proposed. The procedure consists of pointing the receiving telescope of the spectrometer to nonreflecting surfaces or to bright targets placed at known distances from the measuring device, which are illuminated by sunlight. We show that the partial trace gas absorptions between the top of the atmosphere and the target can be easily removed from the measured total absorption. Thus it is possible to derive the average concentration of trace gases such as NO(2), HCHO, SO(2), H(2)O, Glyoxal, BrO, and others along the line of sight between the instrument and the target similar to the well-known long-path DOAS observations (but with much less expense). If tomographic arrangements are used, even two- or three-dimensional trace gas distributions can be retrieved. The basic assumptions of the proposed method are confirmed by test measurements taken across the city of Heidelberg.     

Dual quantum cascade laser trace gas instrument with astigmatic Herriott cell at high pass number

We have developed and demonstrated a high-sensitivity trace gas instrument employing two mid-infrared quantum cascade lasers and an astigmatic Herriott sample cell with up to a 240?m path length. Several aspects of astigmatic Herriott cell optics have been addressed to enable operation at a high pass number (up to 554), including aberrations and pattern selection to minimize interference fringes. The new instrument design, based on the 200?m cell, can measure various atmospheric trace gases, depending on the installed lasers, with multiple trace gases measured simultaneously. Demonstrated concentration noise levels (1?s average) are 40?parts per trillion [(ppt) 10(-12)] for formaldehyde, 10?ppt for carbonyl sulfide, 110?ppt for hydrogen peroxide (H2O2), and 180?ppt for nitrous acid (HONO). High-precision measurements of nitrous oxide and methane have been recorded at the same time as high-sensitivity measurements of HONO and H2O2.     

Development of ion drift-chemical ionization mass spectrometry

An ion drift-chemical ionization mass spectrometry (ID-CIMS) technique has been developed to detect and quantify trace gases, including volatile organic compounds and inorganic species. The trace species are chemically ionized into positive or negative product ions with a well-controlled ion-molecule reaction time. The ID-CIMS method allows for quantification of the trace gases without the necessity of performing calibrations with authentic standards for the trace gases. Demonstrations of the ability of ID-CIMS to accurately quantify isoprene and HNO3 in a laboratory setting are presented. The results illustrate that the ID-CIMS technique facilitates detection and quantification of organic and inorganic species in laboratory kinetic investigations and field measurements.     

纳米光催化净化分解炼化厂恶臭有毒气体研究

对炼油厂典型的恶臭、有毒有害气体硫化氢、甲基醇与乙硫醇进行了纳米光催化净化分解模拟试验，在此基础上研制出纳米光催化空气净化样机，并对样机进行了初步测试。     

Lidar equation for a broadband optical range

We have numerically studied the use of a genetic algorithm for reconstructing vertical concentration profiles of trace atmospheric gases from the data of pulsed broadband lidar sounding in a frequency range covering the regions of selective optical absorption of these gases. A generalized form of the lidar equation is proposed that takes into account finite spectral intervals of backscattered radiation. The possibility of using pulsed excilamps of the new generation as sources of radiation for the optical sounding of the atmosphere is demonstrated for the first time. The validity of the proposed approach is illustrated by quantitative examples.     

FTIR和光谱差减法的大气质量检测

针对大气质量检测的多组分定量分析,本文提出利用傅里叶变换红外光谱（FTIR）技术与光谱差减相结合的气体定量方法。该方法是根据迈克尔逊干涉原理与朗伯．比尔定律,采用怀特型长光程气体池与FTIR光谱仪相结合的方式来测得痕量气体的红外光谱,最后利用光谱差减法反演出气体浓度。为了避免背景环境的干扰（主要是避免水和CO2吸收峰的干扰）,选择了在某些特殊波段内的待测气体吸收峰进行分析。本文分别对CO,SO2,NO2,NO和CO2气体进行了定量分析,相应的最佳观测波段依次为：2250～2020cm^-1,1230～1070cm^-1,2940～2840cm^-1,1965～1775cm^-1,668．24cm^-1。实验结果表明,经浓度反演相对误差可达到10％以内。