标准气体在检测可燃气体报警器中的重要性

介绍可燃气体报警器的检测现状，分析可燃气体报警器检测元件中毒的原因，强调了检测可燃气体报警器时使用标准气体的重要性，以及标准气体的正确使用。     

可燃气体检测报警器检定用标准物质的选择

可燃气体检测报警器,亦称测爆仪,广泛应用于危险化学品场所中可燃性气体泄漏事故的检测报警,属于国家强制检定的工作用计量器具。JJG693-2004可燃气体检测报警器(以下简称报警器)国家计量检定规程(以下简称规程)经国家质量监督检验检疫总局于2004年3月2日批准,并自2004年9月2日     

有毒有害气体报警器检测探讨

介绍了常见有毒有害气体检测报警器的分类。对气体检测报警器的检测方法进行探讨,为此类报警器的检测方法提供建议。     

一种新型气体报警器检定操作台的研制

针对有毒有害气体报警器检定过程中存在的安全防护问题,研制了一种防毒防害型气体报警器检定操作台,该操作台主要由操作台体、透明橱窗、排风装置、转子流量计、减压阀等组成。该操作台可以提高计量检定实验室在有毒有害气体报警器检定时对环境条件的控制能力。     

可燃气体检测报警器计量检定与计量管理的探讨

指出了可燃气体检测报警器计量检定的重要性,结合河南省南阳市辖区内可燃气体检测报警器计量检定的现状,着重分析了计量检定与计量管理存在的问题和难点,并且提出了相关建议。     

气体报警器检定用智能控制终端的设计与实现

介绍了一种用于有毒有害气体报警器计量检定用手持控制终端的设计。通过对手持终端的软件、电源系统、无线通信系统和主控系统的研发,实现了无线控制报警器检定的操作,并可在手持终端上显示报警器的相关参数以及检定结果等内容。该手持终端提高了检定效率,避免了有害气体对检定人员的侵袭。     

氰化氢气体检测报警器的校准

建立氰化氢气体检测报警器的校准方法.通过模拟实际的气体扩散状况,分别对扩散式电化学传感原理的氰化氢气体检测报警器的示值误差、重复性、响应时间等项目进行校准.总结了多台仪器的校准结果,提出了科学合理的氰化氢气体检测仪校准的技术指标:绝对误差为±2μmol/mol,或者相对示值误差不大于10％,满足其一即可;重复性不大于3...     

标定罩使用对气体报警器检定结果的影响

为指导检定人员在气体报警器检定时对气体标定罩的正确使用,对标准罩、大罩、小罩、不带罩4种情况进行试验,并对气体报警器检定结果的绝对误差、响应时间、重复性等参数进行对比分析。结果表明,在满足绝对误差±5%FS之内、响应时间不大于60 s、重复性不大于2%的技术指标要求时,使用标准罩能够得到更准确、稳定、符合现场模拟真实数值的检定结果。该研究有利于提高气体报警器检定结果的准确性。     

复合式气体报警器检定装置的研制

提出一种新型复合式气体报警器检定方法,根据此方法设计一套复合式气体检测报警器检定装置。该检定装置由工作柜、气瓶存储柜、气体输送气路、流量控制器、气体稀释装置、旋转工作台6部分组成。其中气体输送气路共有6路通道,气体稀释装置的重复性不大于0.5%。旋转工作台可同时对多台仪器进行测量,另外还配备了证书编辑软件。该装置检定结果的扩展不确定度不大于5%(k=2),其中:用于0~100%LEL CH4检定的扩展不确定度为3.0%(k=2);用于0~100μmol/mol H2S检定的扩展不确定度为5.0%(k=2);用于0~100μmol/mol CO检定的扩展不确定度为4.2%(k=2);用于0~20.9%O2检定的扩展不确定度为3.4%(k=2)。该检定装置工作效率高,采用PLC和上位机的控制方式能够实现检定过程自动化测量。该装置主要适用于CH4,H2S,CO,O2气体报警器的检定。     

基于UWP跨平台移动式可燃气体检测报警器智能检定系统的研制

将UWP(Windows通用应用平台)技术应用于可燃气体检测报警器智能检定系统的设计,研制移动式可燃气体检测报警器智能检定系统。该系统包括移动端和PC端,移动端包括委托单信息处理、检定数据处理、数据上传、XML数据管理4个模块;PC端包括上传信息读取、委托单/证书/记录生成及打印两个模块。该系统的研制实现了检定系统在手机、平板、智能检定工作台等的跨平台应用,提高了报警器的检定效率。     

烷基化汽油中烃的类别分析

在程序升温条件下，用气相色谱法分析烷基化汽油样品，将各组分的程序升温保留时间转化的恒温保留指数。根据各组分在SE-54固定相和OV-1固定相上的气相色谱保留指数差对其进行类别定性。利用色谱-质谱分析法进行了验证，结果表明该方法简便可行。     

ZTGC-900D型气相色谱仪的常见故障及其排除

介绍ZTGC-900D型气相色谱仪使用过程中出现的几起故障,对故障进行分析、诊断,提出了故障的排除方法。     

钙钛矿型稀土复合氧化物催化剂上一氧化碳的选择氧化

考察了在钙钛矿型稀土复合氧化物催化剂上，氢气中一氧化碳选择氧化的催化性能，发现该催化剂具有优良的催化活性和选择性。LaMnO3中的锰被铜部分取代后可以提高其催化活性，当其中的镧再被锶或钡部分取代后所得的催化剂的催化活性进一步提高。其中以La0.8Sr0.2Mn0.5Cu0.5O3的催化活性为最佳，在该催化剂上，在40 000 mL·g－1·h－1下，155 ℃时CO可被完全转化为CO2，此时的选择性达54%，与铂催化剂的性能相近。反应气中加入CO2时，CO转化率下降，但选择性有所提高；加入水蒸气则使CO的转化率和反应选择性均下降。     

金属氧化物异质结气体传感器气敏增强机理

金属氧化物异质结由于费米能级效应、不同组分之间的协同作用,常被用来提高电阻型金属氧化物半导体气体传感器的气敏特性。本文简述了近年来国内外金属氧化物异质结材料的类别,主要分为混合氧化物结构、层状结构、第二相粒子修饰结构、一维纳米结构和核-壳结构;重点综述了金属氧化物异质结的气敏增强机理,包括异质结效应、协同效应、催化溢流效应、响应反型、载流子分离及微结构调控六大机理;分析了当前异质结气体传感器面临的瓶颈。最后对纳米异质结气体传感器的发展进行了展望,今后金属氧化物异质结气体传感器可以从明确异质结界面机理展开,这将为自下而上地设计出符合实际需要的气体传感器提供一定参考。     

Reversible Carrier‐Type Transitions in Gas‐Sensing Oxides and Nanostructures

Despite many important applications of α‐Fe₂O₃ and Fe doped SnO₂ in semiconductors, catalysis, sensors, clinical diagnosis and treatments, one fundamental issue that is crucial to these applications remains theoretically equivocal—the reversible carrier‐type transition between n‐ and p‐type conductivities during gas‐sensing operations. Herein, we present an unambiguous and rigorous theoretical analysis in order to explain why and how the oxygen vacancies affect the n‐type semiconductors α‐Fe₂O₃ and Fe‐doped SnO₂, in which they are both electronically and chemically transformed into a p‐type semiconductor. Furthermore, this reversible transition also occurs on the oxide surfaces during gas‐sensing operation due to physisorbed gas molecules (without any chemical reaction). We make use of the ionization energy theory and its renormalized ionic displacement polarizability functional to reclassify, generalize and explain the concept of carrier‐type transition in solids, and during gas‐sensing operation. The origin of such a transition is associated with the change in ionic polarizability and the valence states of cations in the presence of oxygen vacancies and physisorped gas molecules.     

Comparative analysis in different organs and tissue-specific metabolite profiling of Atractylodes lancea from four regions by GC–MS and laser microdissection

Traditional Chinese medicine is made from the rhizome of Atractylodes lancea (Thunb.) DC. (Compositae), known as Cangzhu. In this study, gas chromatography-mass spectrometry was used to identify and quantify the volatile oils of different organs of A. lancea from four regions of China: Jiangsu, Anhui, Henan, and Hubei provinces. The volatile oils of A. lancea were qualitatively and quantitatively characterized using gas chromatography-mass spectrometry combined with laser microdissection. The results identified 21 components in A. lancea, the majority of the components were found in the rhizomes, followed by the fibrous roots, flowers, leaves, and stems. According to the contents of volatile oils in A. lancea, it was divided into Dabieshan (mainly includes hinesol and β-eudesmol) and Maoshan types (mainly includes atractylon and atractylodin), and the ratios of hinesol:β-eudesmol:atractylon:atractylodin were 17.06:4.55:0:1, 12.66:11.71:0.99:1, 7.43:6.23:0:1, and 0.13:0.16:1.52:1 in A. lancea from AH, HN, HB, and JS, respectively. Tissue-specific study indicated that Dabieshan type mainly includes elemol, hinesol, and β-eudesmol in the periderm and secretory cavities of A. lancea, whereas Maoshan type mainly includes atractylon, atractylodin, little hinesol, and β-eudesmol in the secretory cavities. Conversely, no volatile oils were detected in the cortex, phloem, xylem, vascular ray, or pith. This study provides a foundation for further evaluation and utilization of A. lancea.     

空心纳米金在甲醛气体传感器中的应用研究

通过牺牲模板法合成了具有空心结构的纳米金催化剂,并进行了TEM、 SEM和XRD等物理表征.把该催化剂作为工作电极的活性物质,以1 mol/L KOH为电解质,组装了电流型甲醛气体传感器.在甲醛气体浓度为0～2.23×10-6 mol/L范围内对传感器进行了性能测试,传感器响应信号y(A)与气体浓度x(mol/L)线性回归方程为y=16.63x+4.063×10-7, r=0.9989.该传感器灵敏度高于同载量实心金纳米催化剂组装的传感器70%左右,达到了降低贵金属用量的目的.因其具有较快的响应时间、 良好的重现性和良好的线性关系等优点,可用于适当浓度范围内的甲醛气体检测.     

Hydrocarbon type analysis by thin-layer chromatography with flame-ionization detection: vacuum gas oils, heavy feeds, and hydroprocessed products

Thin-layer chromatography with flame-ionization detection (TLC-FID) provides quantitative hydrocarbon type data as well as distribution of aromatics by ring number. This method has been applied to obtain amounts of saturates, aromatics, and polars in heavy oil distillates such as light vacuum gas oils and heavy vacuum gas oils derived from different crude sources. TLC-FID chromatograms and resultant quantitative hydrocarbon type data show that these distillates vary markedly in aromatic contents and aromatic ring types. Similar observations are made with several fluid catalytic cracking feeds. Effects of process parameters such as operating pressure and temperature on hydroconversion of aromatics and polars from a heavy oil are assessed by TLC-FID. It has been demonstrated that there is a preferential reduction of higher polycyclic aromatic hydrocarbons and polars with an increase of both hydrogen partial pressure and reactor temperature.     

几种尖晶石型复合氧化物纳米粉体的制备及气敏性

采用化学共沉淀法合成了4种尖晶石型复合氧化物MFe₂O₄(M=Cu²⁺,Zn²⁺,Cd²⁺,Mg²⁺).X射线粉末衍射分析、透射电镜及比表面测定等表征结果表明它们均为具有较大比表面积的纳米粉体,平均粒径<50nm.将样品做成厚膜型气敏元件,测定了其对乙炔、液化石油气、一氧化碳、氢气和乙醇等还原(可燃)性气体的气敏特性。     

Hydrocarbon type analysis by gas chromatograph using a single capillary column and a multi-column valve system

Summary Two different gas chromatographic methods are used for the determination of hydrocarbon type distribution in naphtha and gasoline samples with final boiling points up to 275 °C. The methods are based either on a single capillary column or on a valve-switched packed column system. Both methods give extensive information on paraffins, olefins, naphthenes and aromatics in total as well as by carbon-number. In each case the analysis is fully automated with a computer controlling the entire analysis from injection to results presentation. The advantages and limitations of both methods are discussed.Presented at the 14th International Symposium on Chromatography London, September, 1982