气质联用仪在六氟化硫杂质痕量分析中的应用

通过实验阐明了气质联用在气体分析中的应用,对气体中不同浓度六氟化硫的线性、数据重复性以及灵敏度进行考察,确定了气质联用仪对气体中六氟化硫杂质痕量分析的可靠性。     

六氟化硫中杂质含量测量不确定度评定

采用氦离子化气相色谱法和光腔衰荡法依照国家标准GB/T 18867—2014《电子工业用气体六氟化硫》测定六氟化硫中杂质气体含量和水分含量,通过分析测量过程中不确定度的来源,对各不确定度分量进行评定及结果判断。评定结果表明:六氟化硫中杂质气体含量的测量不确定度主要来源于标准气体。     

电力用六氟化硫纯度检测的色谱分析技术开发

六氟化硫气体作为迄今为止最为优良的气体绝缘介质和灭弧介质,广泛应用于GIS等电力高压电气设备中,六氟化硫气体中含有的杂质气体不仅对其绝缘性和灭弧产生影响,而且会对SF6分解产物的分析造成误判。大量的经验证明,六氟化硫新气中通常含有O2、N2、CH4、CO、CF4、CO2、C2F6、C3F8、CS2和SO2等10种气体杂质,开发对这10种杂质气体的分析方法,对判断六氟化硫新气的质量具有重要的指导意义。采用国家标准GB/T 12022《工业六氟化硫》中推荐的方法无法完成上述10种杂质的分析;目前在电力系统广泛应用的六氟化硫分解产物氦离子化气相色谱法造价高昂。本方法仅需1个氦离子化检测器(PDHID),1个十通阀和2个六通阀,即可实现上述10个杂质的分离和定量分析,仪器成本大幅降低的同时,检出限、重复性和线性等指标均满足分析要求,因此该方法完全可以适用于SF6新气质量评价。     

六氟化硫气体湿度现场检测及其应用

[摘要]文中简介了六氟化硫气体的基本性质，阐述了六氟化硫设备中水分来源的四个方面以及水分的存在造成的四大危害；介绍了电气设备中六氟化硫气体湿度的现场检测方法，检测原理，阐述了六氟化硫气体在GIS设备中的应用，通过对我局六氟化硫设备开展六氟化硫气体湿度现场检测，使我们对六氟化硫气体湿度的检测有了深刻的认识和了解，同时也提高了对六氟化硫设备的检测率，保证六氟化硫设备安全可靠的运行。     

我国工业六氟化硫纯化技术近况及改进

重点介绍了六氟化硫中可水解氯化物杂质气体的去除方法及其干燥吸附剂的选择，并对我国六氯化硫气体的纯化技术提出了改进建议。     

六氟化硫中有毒杂质生成机理

对六氟化硫气体中的多种有毒杂质四氟化硫、十氟化二硫、十氟化二硫一氧、亚硫酰二氟、硫酰二氟、亚硫酰四氟、二氟化氧、氟化氩和二氧化硫等形成机理进行了初步探讨。     

在线测量压力式六氟化硫气体密度控制器不确定度分析研究及验证方法

压力式六氟化硫气体密度控制器是核电厂重要的阀门设备,直接与核安全相关。对压力式六氟化硫气体密度控制器的计量丁作是核电厂安全生产、保障效益的重要基础性工作之一。本文依据JJG 1073—2011《压力式六氟化硫气体密度控制器检定规程》对压力式六氟化硫气体密度控制器在线测量不确定度的评定方法进行研究和实验,并用比对的方法对小确定度进行验证,确保测量结果更规范。     

便携环保型六氟化硫气体断路器快速充气装置的设计与实施

本文主要介绍了便携环保型六氟化硫气体断路器快速充气装置的设计与实施,具体介绍了研究背景,分析了六氟化硫气体的性质与SF6气体断路器特点,探讨了便携式六氟化硫气体断路器快速充气装置的设计方案,研究了便携式六氟化硫气体断路器快速充气装置的具体实施方式。     

六氟化硫气体中微量杂质分析的研究

用两种气相色谱法测定了六氟化硫气体中微量杂质：Air、CF4、C3F8、SO2F2、SOF2、S2F10O,比较了热导—火焰光度串联法与氦离子色谱法的分析结果,相对误差小于3.0%,并对分析结果中的问题进行了讨论。     

多功能六氟化硫气体测试采样装置的研究与应用

本文从六氟化硫气体测试采样过程中遇到的三个关键问题入手,思考如何提高现场六氟化硫气体测试的效率,且减少六氟化硫污染和对人体的危害,从而设计出一套简易高效的多功能六氟化硫气体测试采样装置,并应用在六氟化硫气体试验现场。     

Micro texturing of silicon using pulsed N(2)-laser and formation mechanism

A low-cost pulsed N(2)-laser has been used to successfully demonstrate the formation of self-organized conical microtexture in Si. The process is demonstrated in vacuum environment to avoid the use of SF(6) gas and sulfur incorporation. The microtexture is formed with an average structure height of ~15 um, base diameter ~10 μm, and tip-to-tip separation ~8 μm. Energy dispersive x-ray spectroscopy of individual conelike structure shows that the material remains free from impurity incorporation. We have shown that the laser-induced-damage-related absorption can be successfully restored after an hour annealing at 1000 °C, making the material an ideal candidate for photovoltaic and other photonic applications.     

Fine purification of monoisotopic <Superscript>32</Superscript>S and <Superscript>34</Superscript>S

We have proposed and tested a combined process for ultrapurification of monoisotopic ³²S and ³⁴S sulfur, which comprises thermochemical treatment of sulfur vapor on silica and ceria packing, melting with aluminum, and distillation. The impurity composition of the purified sulfur has been determined by atomic emission and IR spectroscopy. We have obtained monoisotopic ³²S and ³⁴S sulfur samples comparable in chemical purity to high-purity sulfur of natural isotopic composition.     

Mechanisms for thermal stability of the electrophysical properties of overcompensated n-Si〈B, S〉

Thermal annealing was used to study silicon samples having different sulfur concentrations. It was established that the temperature at which the sulfur centers decay depends on the concentration of sulfur atoms N _s in the overcompensated silicon. As the distance between the impurities (N _s ^−1/3 ) decreases, the decay temperature increases. The effect can be attributed to characteristic features of the distribution of the compensating sulfur impurity atoms inside a region of fluctuation, formed in silicon during doping. Pis’ma Zh. Tekh. Fiz. 25, 1–4 (December 26, 1999)     

Impurity composition of monoisotopic <Superscript>28</Superscript>SiF<Subscript>4</Subscript> silicon tetrafluoride

The impurity composition of ²⁸SiF₄ has been studied for the first time by gas chromatography/mass spectrometry using gas-adsorption capillary columns. For identification and determination of impurity substances by gas chromatography/mass spectrometry, we have proposed using cryogenic preconcentration of the impurities from ²⁸SiF₄. The presence of C₂–C₄ hydrocarbon impurities and sulfur hexafluoride has been confirmed. We have identified 35 impurity substances in ²⁸SiF₄, including linear and branched C₅–C₈ saturated hydrocarbons, aromatic hydrocarbons, chlorine- and fluorine-containing hydrocarbons, and silicon- and sulfur-containing substances, of which 28 have been detected for the first time.     

Influence of Impurities and Additives on the Phase Composition of Reaction Products and Heat Generation in the Fe–C–NaCl–H2O–O2 System

Thermodynamic analysis is used to assess the effects of various impurities in Fe and additives on the equilibrium phase composition of reaction products and heat generation in the Fe–C–NaCl–H₂O–O₂ system. It is shown that manganese impurity increases heat generation. Manganese, sulfur, and sulfur compounds decrease the equilibrium concentrations of gaseous species (H₂, CH₄, CO, H₂O) forming during storage. Experimental results indicate that the gas evolution in the system can be reduced by pretreating the Fe powder with sulfur compounds, without significantly reducing the heat generation.     

Hot corrosion: a modification of reactants causing degradation

Abstract

It has been conjectured that if sulfur in the fuel is removed, engine materials will cease to experience attack from hot corrosion since the fuel sulfur has been viewed as the primary source that has caused hot corrosion and sulfidation. Hot corrosion has been defined as an accelerated degradation process that is generally considered to involve deposition of corrosive species (e.g. sulfates) from the surrounding environment (e.g. combustion gas) to the surface of hot components, followed by subsequent destruction of the protective oxide scale. Most papers in the literature since the 1970s consider sodium sulfate as the single salt causing hot corrosion. There has been a push to remove fuel sulfur content to less than 15 ppm. However, sulfur species may still enter the combustion chamber via air intake or with seawater entrained in the air through the air intake of the ship. Seawater contains, in addition to sodium sulfate, magnesium, calcium, and potassium salts. Additionally, sulfate speciation and the content of atmospheric particulate matter (PM) varies considerably around the world and in some places, such as China and India, high PM seems to cause an increased risk of deposit-induced hot corrosion due to atmospheric pollutants rather than a combustion process (i.e. sulfur impurity in the fuel). The increasing operating temperatures of turbine engines and activities within regions of the world that have relatively high pollutant (PM, SO₂, C, Ca, etc.) levels are working conjointly to cause previously unobserved forms of high-temperature corrosion. This paper will cover some of our revised understanding of hot corrosion and consider other possible contaminants that could further complicate our understanding of hot corrosion.     

Modeling of impurity cloud propagation under the action of wind in the ground layer

A qualitative analysis and numerical modeling of two- and three-dimensional problems on stationary propagation of a gas impurity under the action of the wind are carried out. It is shown that vertical turbulent diffusion is a major channel of impurity dispersion. A comparison with the data of proving-ground tests confirmed this conclusion. An analytical expression is obtained for the characteristic length of impurity scattering that amounts to about 10–15 m, and it is shown that this length is independent of the wind velocity and is determined by the properties of the underlying soil surface.     

Numerical analysis of clogging dynamics in micromachined Joule–Thomson coolers

Micromachined Joule–Thomson (JT) coolers are of interest for cooling small electronic devices. The long-term performance of JT microcoolers is limited by the clogging phenomenon caused by the deposition of water molecules present as impurity in the working fluid. This work investigates the clogging dynamics in a JT microcooler operating with nitrogen gas. A numerical model is developed to calculate the temperature profile and the deposition rate of water molecules along the counter flow heat exchanger and the restriction of a microcooler. The deposition process is modeled by considering the diffusion of water molecules in nitrogen gas and the kinetic process of water molecules on wall surface, which are both temperature dependent. Numerical results show that the clogging rate during cool down is influenced by gas impurity and gas pressure. The effects of gas purity, gas pressure and cold-end temperature on the continuous operating time of the microcooler are also investigated.     

Ions and Atoms in Superfluid 4Helium: Motion Studies and Optical Transitions

In this paper systematic studies of the ion production mechanism are reported. The use of laser ablation inside the liquid is compared to the laser sputtering technique which produces the ions in the gas phase. For the first time impurity ions produced directly in the liquid could be separated from other sputtering products in the laser focus and identified unambigously by their characteristic emission light during the recombination process with electrons emitted from a field emission tip. This technique is important for future, pressure dependent measurements of the ionic mobility in liquid helium when ion production in the gas phase is impossible. Furthermore, optical transitions of various elements implanted into liquid helium are reported which became observable due to an improved set-up used in this experiment.     

甲烷中微量氧、氮、乙烷气体标准物质的研制

介绍了甲烷中微量氧、氮、乙烷气体标准物质的制备过程,建立了杂质组分的分析方法,对该标准物质性能进行了分析与考察,分析和评定了标准物质的不确定度.