二氧化碳中微量氧硫化碳标准气体的稳定性

主要讨论了影响二氧化碳中微量氧硫化碳标准混合气的稳定性因素。实验数据表明影响二氧化碳中微量氧硫化碳标准物质贮藏期限的主要因素是材料的选择和气瓶的处理。选择合适的材质和气瓶处理过程,浓度范围为（100-200）×10^-9（mol／m01）氧硫化碳标准混合气至少可以存放12个月。     

不同热处理对钻杆材料硫化氢应力腐蚀性能的影响

随着酸性油气田的陆续出现,钻杆在酸性环境下腐蚀性能的研究显得尤为重要。通过拉伸试验、冲击试验、硬度测试及硫化氢应力腐蚀试验(SSC)等对不同热处理后V150钻杆材料的硫化氢应力腐蚀性能进行了研究。结果表明:热处理可以提高V150钻杆材料的抗硫化氢应力腐蚀性能;在淬火温度一定的情况下,抗拉强度、屈服强度及硬度随回火温度的升高呈逐渐降低的趋势,冲击韧性呈逐渐升高的趋势;抗SSC性能随着回火温度的升高逐渐提高;夹杂和缺陷是导致V150钻杆材料抗SSC性能降低的主要原因。     

Advancements in the selective inhibition sintering process development

Selective inhibition sintering (SIS) is a new layer-based rapid prototyping process that fabricates parts by joining polymer powder particles in the part's body to form a coherent solid and by preventing particles from joining at the part's boundary to form edges. This paper presents the fundamentals of the SIS process, its dedicated path generator, material selection research and the application of response surface methodology which has led to optimum performance, given various factors affecting part strength, surface quality and dimensional accuracy.     

Advancements in the selective inhibition sintering process development

Selective inhibition sintering (SIS) is a new layer-based rapid prototyping process that fabricates parts by joining polymer powder particles in the part's body to form a coherent solid and by preventing particles from joining at the part's boundary to form edges. This paper presents the fundamentals of the SIS process, its dedicated path generator, material selection research and the application of response surface methodology which has led to optimum performance, given various factors affecting part strength, surface quality and dimensional accuracy.     

Surface sulfurization studies of thin film Cu(InGa)Se2 solar cells

Sulfurization of copper indium gallium diselenide (CIGS) thin films solar cell absorber has been attempted to enhance the open circuit voltage of the device by increasing the band gap of the absorber near the interface. The homogeneous co-evaporated Cu(InGa)Se₂ thin film was used for sulfurization. The sulfurization was studied in hydrogen sulfide and mixture of hydrogen sulfide and hydrogen selenide gases with the inclusion of oxygen. The structural and compositional properties of the absorber layers were investigated by XRD, EDS and AES analysis. The device results were characterized using current-voltage (I-V) and quantum efficiency. Sulfurization in hydrogen sulfide gas forms a fully converted sulfide layer at the top of the absorber layer, which in turn forms a barrier for the current collection; the device results also support this observation. Sulfurization in mixture of hydrogen sulfide and hydrogen selenide gases forms a wide band gap Cu(InGa)(SeS)₂ layer at the surface by partial replacement of Se by S. The device does not show an increase in open circuit voltage. This may be attributed to the diffusion of Ga away from the surface with the inclusion of sulfur at the surface, which counters the beneficial effect of sulfur at the surface.     

Study of Factors Affecting the Surface Quality in Ultra-Precision Diamond Turning

This paper deals with an investigation of the process factors and the material factors affecting the surface roughness in ultra-precision diamond turning. The process factors involve cutting conditions, tool geometry, and relative tool-work vibration which are related to the cutting geometry and the dynamic characteristics of the cutting process. The material factors considered are material anisotropy, swelling, and crystallographic orientation of the work materials. Experimental results indicate that the influence due to the process factors can be minimized through a proper selection of operational settings and better control of dynamic characteristics of the machine. The material factors, on the other hand, exert consistent influence on the surface roughness which can not be minimized solely by an optimization of process parameters and machine design. Based on these findings, some suggestions are proposed for the optimization of the surface quality in ultra-precision diamond turning.     

The morphology and corrosion resistance of a conductive silver-epoxy paste

Among the important properties of conductive silver-epoxy pastes are their relatively low internal electrical resistance and their low rate of sulphidizing relative to pure silver. To investigate these properties in more detail and to gain understanding of the physical mechanisms involved, paste and bulk silver samples have been exposed to a controlled corrosive atmosphere of hydrogen sulfide and water vapour in purified air. The exposed samples were then analysed by a variety of surface and bulk techniques. The results demonstrate that (1) although the contact resistance of the bulk silver is initially much lower than that of the conductive paste, it increases much more rapidly with long exposure to corrosive atmospheres than that of the paste; this is especially true at low contact probe forces, (2) the hydrogen sulfide permeation constant through a free-standing film of unsilvered paste is (7.0±0.3)×10^–2 barrers: sufficiently low that transport of H₂S into the bulk paste is strongly inhibited, (3) silver flakes projecting outward from the surface of the paste have little or no resin coating. Corrosion thus occurs on the surface of the material but is inhibited within the material. The relative softness of the material allows contact probe penetration into the uncorroded bulk matrix. As a result, little decrease in the conductivity of the paste occurs even after extended exposures to a corrosive environment.     

储氢材料与噻吩反应中的影响因素分析

采用氢气反应球磨法制备Mg/C复合材料,利用储氢材料受热释放出的氢和噻吩进行加氢反应,分析了加氢反应中的相互影响因素。结果表明,噻吩加氢反应对氢分压影响小,储氢材料的放氢量低于其同温下连续放氢量;升高温度及适当延长反应时间,反应产物中的固相硫含量增多,但反应时间过长,固相硫含量基本稳定不变;适当的材料粒径对固硫有益,但粒径过细不利于固相硫的产生。     

Biofiltration of hydrogen sulfide‐containing waste gas by entrapped mixed microbial cells

Abstract

The study demonstrates a novel attempt to use an aerobic biofiltration system containing entrapped mixed microbial cells (EMMC) for removal of hydrogen sulfide dominant waste gases. In the study, heterotrophic microflora‐immobilized cellulose was packed into an EMMC reactor to degrade hydrogen sulfide. Effects of hydrogen sulfide concentrations for continuous operation at various flow rates indicated that hydrogen sulfide removal efficiency is higher than 90% at inlet loadings below 4.31 mg‐S/min for retention time of 5.3 minutes. This EMMC biofiltration system also showed high tolerance to fluctuations in flow rates while maintaining stable removal performance. The predicted kinetic constant k and maximum mass loading are 0.018 s–1 and 8.64 mg‐S/min, respectively. Adaptability tests in response to gradual shifts up and down of inlet hydrogen sulfide loading indicated that the EMMC microbial communities were well‐acclimated to maintain long‐term operation stability for continuous treatment.     

Adsorption of hydrogen sulfide on graphite derived materials modified by incorporation of nitrogen

Adsorbents for hydrogen sulfide were prepared by heat treatment at 950 °C of spent graphite oxide based materials previously used as ammonia removal media. The materials were characterized using adsorption of nitrogen, potentiometric titration, thermal analysis, FTIR and XRD. The dynamic adsorption experiments showed an enhanced adsorption capacity owing to the presence of basic nitrogen functionalities. Although on the surface of adsorbents hydrogen sulfide was mainly oxidized to elemental sulfur small amount of SO₂ was also formed. The removal capacity was found to depend on the dispersion of nitrogen containing species, which is governed by the porosity and structure of the adsorbents. The amount of nitrogen incorporated depends on the amount of ammonia on the surface and on the surface reactivity. The latter is determined by the amount of oxygen containing groups and the level of structural heterogeneity.     

Conformational behavior of DNA-templated CdS inorganic nanowire

We describe the conformational behavior and morphological control of DNA-mineralized CdS nanowires in a bulk solution. The conformational behavior of individual double-stranded DNA in the presence of cadmium ions and stoichiometric mixtures of cadmium ions and sulfide ions was directly visualized by fluorescence microscopy. It was found that in the presence of mixtures of cadmium ions and sulfide ions, DNA molecules exhibit a conformational transition from an elongated coil to a compacted state. Mineralized DNA nanowires possess a significant conformational freedom at a microscale, and flexibility in the micro- and nanodimensions. The density of the inorganic material on the nanowire can be controlled by varying the concentrations and the molar ratio of Na(2)S to Cd(ClO(4))(2).     

Electronic properties of ruthenium sulfide–carbon cluster composite material obtained by calcination of an alternating ruthenium–S–phenylene hybrid copolymer

Calcination of an alternating ruthenium–S–phenylene hybrid copolymer under an argon atmosphere was found to give nano-sized ruthenium sulfide/carbon cluster composite material. ESR spectral examinations of the material revealed that an electron transfer from ruthenium sulfide particles to carbon clusters took place to raise a visible-light responsive oxidation–reduction function with an oxidation site at ruthenium sulfide particles and a reduction site at carbon clusters. The surface of the calcined material was modified with Pt particles, and the reduction ability of the resulting modified material was examined.     

Evaluation of small hydrogen sulfide concentrations in calibrating commercial gas analyzers for hydrogen sulfide

Conclusions Small concentrations (10^–5–10^–2 by volume) of hydrogen sulfide in gas mixtures can be analyzed by means of the photocolorimetric method based on the formation of molybdenum blue by the interaction of hydrogen sulfide with ammonium molybdate in an acidic medium.The optimum conditions for reducing molybdate by hydrogen chloride are provided by a content of 50 mg/ml of ammonium molybdate in the absorbing solution, a sulfuric solution with an acidity of 0.6 N, and a coloration ripening time of 15–20 min.     

Using carbon nanotubes to absorb low-concentration hydrogen sulfide in fluid

Hydrogen sulfide is a colorless and flammable gas under room temperature. Usually hydrogen sulfide is considered to be toxic; however, the recent research revealed that hydrogen sulfide in the cardiovascular system plays the role of a vascular dilator. The physiological role of hydrogen sulfide depends on its in vivo level. As such, the measurement of hydrogen sulfide with nano-quantity resolution becomes an important subject. Existing methods generally require bulky samples and are invasive and offline. It will be significantly helpful to measure hydrogen sulfide with a small amount of tissue in a noninvasive method The first attempt was to take a blood or serum sample with a trace amount to examine the interaction between hydrogen sulfide and carbon nanotube. The carbon nanotube is chosen because of a known fact that hydrogen sulfide can be adsorbed by activated carbon. The carbon nanotube is an excellent activated carbon in this regard. Fluorescence intensity of the carbon nanotube with and without immersion of it in a hydrogen sulfide medium was examined in the study. It was found that the intensities increase as the concentrations of hydrogen sulfide increase. Furthermore, the concentration of 10$muhboxM$hydrogen sulfide in water was successfully measured.     

Hydrogen catalytic oxidation reaction on Pd-doped porous silicon

The efficiency of Pd-doped porous silicon (PS) as a catalytic material for hydrogen sensing is studied. Pd is deposited by an electroless process on the internal surface of porous silicon. The catalytic behavior of Pd-doped PS samples is estimated and the parameters that influence the kinetics of the chemical reaction are evaluated. The catalytic activity is examined through the kinetics of the chemical reaction, which occurs in low hydrogen content mixtures with air (up to 1% v/v in air), far below the mixture flammability limit. It was found that the catalytic activity of Pd-doped porous silicon at 160°C is significantly higher than that of a planar surface covered with Pd. The dependence of the catalytic activity on processing conditions was also evaluated. These results open important new possibilities for applications in gas sensors     

Failure analysis of monel packing in atmospheric distillation tower under the service in the presence of corrosive gases

We have performed a failure analysis on a monel packing material subjected to sulfidation and sulfide stress cracking after a short period of service in an atmospheric distillation tower containing corrosive gases. Optical macroscopic inspections show that the failed packing material was basically covered with dark scales and corrosion products. Energy dispersive X-ray spectroscopy and X-ray diffraction spectrum show that the corrosion products contain sulfur as the main element along with oxygen indicating that oxidation may have been taken place beside sulfidation. Metallography of the failed samples reveals that cracks exist and were initiated on the surface from defects most likely developed due to the formation of porous and brittle sulfide layer accomplished by hydrogen embrittlement. Although nickel base alloys are an appropriate candidate owing to their high corrosion resistant in corrosive atmospheres, however, presence of H₂S, HCl, O₂ and naphthenic acid in crude oil lead to reduction in corrosion resistant of the monel 400 alloy.     

Microcrystalline silicon prepared with hot-wire CVD

The properties of microcrystalline silicon prepared by hot-wire chemical vapor deposition at various substrate temperatures and process-gas mixtures have been investigated with a view to the application of the material in thin-film solar cells. It was found that high deposition temperatures and strong hydrogen dilution of the process gas have detrimental effects on the electronic performance of the material. It is proposed that under these preparation conditions, hydrogen etching and the thermal desorption of hydrogen lead to poor grain-boundary passivation. We conclude that optimum microcrystalline-silicon solar-cell material is not necessarily obtained with the largest grain sizes and apparent highest crystalline content, but rather by material prepared under conditions that yield a compact morphology with effective grain-boundary passivation.     

Development of a detection sensor for lethal H2S gas

The gas which may be lethal to human body with short-term exposure in common industrial fields or workplaces in LAB may paralyze the olfactory sense and impose severe damages to central nervous system and lung. This study is concerned with the gas sensor which allows individuals to avoid the toxic gas that may be generated in the space with residues of organic wastes under 50 degrees C or above. This study investigates response and selectivity of the sensor to hydrogen sulfide gas with operating temperatures and catalysts. The thick-film semiconductor sensor for hydrogen sulfide gas detection was fabricated WO3/SnO2 prepared by sol-gel and precipitation methods. The nanosized SnO2 powder mixed with the various metal oxides (WO3, TiO2, and ZnO) and doped with transition metals (Au, Ru, Pd Ag and In). Particle sizes, specific surface areas and phases of sensor materials were investigated by SEM, BET and XRD analyses. The metal-WO3/SnO2 thick films were prepared by screen-printing method. The measured response to hydrogen sulfide gas is defined as the ratio (Ra/R,) of the resistance of WO3ISnO2 film in air to the resistance of WO3/SnO2 film in a hydrogen sulfide gas. It was shown that the highest response and selectivity of the sensor for hydrogen sulfide by doping with 1 wt% Ru and 10 wt% WO3 to SnO2 at the optimum operating temperature of 200 degrees C.     

A study on axial cracking failure of drill pipe body

Frequently happening drill pipe failure accidents in oil and gas wells not only affect drilling speed, but cause enormous economic losses and many safety issues. Most of these accidents are transverse cracking of drill pipe body and pin thread or axial cracking of box thread. Based on the axial cracking failures of drill pipe body in an ultra-deep well in China, this paper give a systematic analysis of axial cracking failure in consideration of service condition, material quality and stress corrosion mechanism. Measurement and inspection are performed on macroscopic and microscopic morphology of crack surface, corrosion products and circumferential residual stress. Then stress corrosion cracking experiments against hydrogen sulfide is conducted. Finally, the critical stress value for sulfide stress corrosion cracking of the drill pipe material is obtained, and the mechanisms of axial cracking failure and corresponding preventive measures are proposed.     

Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers

Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d(-1) and 1.33 d(-1) as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.