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燃料电池式乙醇传感器的研制
利用燃料电池反应原理制备乙醇传感器,可精确检测呼气中乙醇浓度,并对烟雾、汽油等典型的干扰气体具有优异的选择性.传感器电极采用价格低廉、物理化学性质稳定的磺化聚α-甲基苯乙烯制固体质子交换膜作为载体材料,降低了传感器的制造成本,并用硅酸乙酯处理质子交换膜负载二氧化硅以改善膜的亲水吸水性能.传感器采用全固态方式装配,避免了液态电化学传感器的电解液泄漏问题.传感器电极采用丝网印刷工艺制备,提高了电极尺寸的一致性、催化剂的分散度和电极的强度,改善了传感器的稳定性,提高了生产效率....
2020-09-30 09:14:00浏览：44
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燃料乙醇温室气体排放与能量投入/产出的探讨
介绍了基于全生命周期评价和生物燃料系统分析模型的燃料乙醇温室气体排放及能量投入/产出研究结果，总结相关研究工作进展。从降低温室气体排放和能量投入/产出比的角度，对燃料乙醇原料的选择、生产工艺优化的指导原则、能源产品多元化以及工厂布局与物流等问题提出相应建议。...
2020-09-30 09:14:00浏览：43
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世界乙烯工业发展新动向
当前世界传统的以石脑油为裂解原料的乙烯工业正遭遇页岩气化工和近代煤化工的严重冲击，页岩气革命为美国和加拿大等国家带来了大量价格低廉的页岩气乙烷和凝析液作为乙烯裂解原料，从而提高了产业竞争力和得到良好的经济效益。建议中国可以借鉴欧洲一些国家的做法，在价格合理的前提下，考虑引进北美乙烷或凝析液作为乙烯裂解原料，进一步提升我国乙烯工业竞争力。...
2020-09-28 16:47:12浏览：49
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Supercritical gasification for the treatment of o-cresol wastewater
The supercritical water gasification of phenolic wastewater without oxidant was performed to degrade pollutants and produce hydrogen-enriched gases. The simulated o-cresol wastewater was gasified at 440-650℃ and 27.6 MPa in a continuous Inconel 625 reactor with the residence time of 0.42-1.25 min. The influence of the reaction temperature, residence time, pressure,catalyst, oxidant and the pollutant concentration on the gasification efficiency was investigated. Higher temperature and longer residence time enhanced the o-cresol gasification. The TOC removal rate and hydrogen gasification rate were 90.6% and 194.6%,respectively, at the temperature of 650℃ and the residence time of 0.83 min. The product gas was mainly composed of H2, CO2, CH4 and CO, among which the total molar percentage of H2 and CH4 was higher than 50%. The gasification efficiency decreased with the pollutant concentration increasing. Both the catalyst and oxidant could accelerate the hydrocarbon gasification at a lower reaction temperature, in which the catalyst promoted H2 production and the oxidant enhanced CO2 generation. The intermediates of liquid effluents were analyzed and phenol was found to be the main composition. The results indicate that the supercritical gasification is a promising way for the treatment of hazardous organic wastewater....
2020-09-25 09:10:57浏览：58
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配煤在煤化工中的应用
配煤技术在满足技术可行性的同时还可实现经济效益和环境效益的最大化，保证用煤设备的高效、安全运行。本文对配煤的作用进行了分析，研究了配煤在锅炉用煤中应用情况，并且以鲁奇气化炉为例，分析了不同煤种的运行情况，为调整工况和均匀布气，需要结合具体的负荷合理搭配使用不同种类的煤种。同时提出了保障气化炉经济运行的措施。...
2020-09-15 12:28:59浏览：64
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Gas Quenching during Age Hardening of the Aluminium Casting Alloy AI-7Si-0.3Mg
For quenching of age hardenable aluminium alloys today predominantly aqueous quenching media are used.which can lead due to the Leidenfrost phenomenon to a non-uniform cooling of the parts and thus to thermal stresses.Particularly at thin-walled or complex shaped parts local plastic deformations can occur by the uneven thermal stresses. In relation to the conventional quenching procedures in aqueous media, gas quenching exhibits a number of technological.ecological and economical advantages. In comparison to liquid quenching media, gas does not change its phase during quenching. Moreover, the cleaning problem of the parts can be avoided. The quenching intensity can be adjusted by the variable parameters gas pressure and gas speed as well as the kind of gas and thus can be adapted to the requirements of the alloy. By the higher uniformity and the better reproducibility, gas quenching offers a high potential to reduce distortion. The goal of these investigations is to clarify, if the cooling rate during gas quenching is sufficient to obtain the specific required strength after age hardening of the alloy A1-7Si-0.3Mg. For this purpose different tests in high-pressure gas quenching facilities, gas nozzle fields and water quenching baths were performed....
2020-09-15 12:28:59浏览：65
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Effect of exhaust gas recirculation and intake pre-heating on performance and emission characteristi
Achieving simultaneous reduction of NOx,CO and unburned hydrocarbon (UHC) emissions without compromising engine performance at part loads is the current focus of dual fuel engine research.The present work focuses on an experimental investigation conducted on a dual fuel (diesel-natural gas) engine to examine the simultaneous effect of inlet air pre-heating and exhaust gas recirculation (EGR) ratio on performance and emission characteristics at part loads.The use of EGR at high levels seems to be unable to improve the engine performance at part loads.However,it is shown that EGR combined with pre-heating of inlet air can slightly increase thermal efficiency,resulting in reduced levels of both unburned hydrocarbon and NOx emissions.CO and UHC emissions are reduced by 24％ and 31％,respectively.The NOx emissions decrease by 21％ because of the lower combustion temperature due to the much inert gas brought by EGR and decreased oxygen concentration in the cylinder....
2020-09-15 12:28:59浏览：84
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Performance assessment of an inline horizontal swirl tube cyclone for gas-liquid separation at high
The application of swirl tube cyclone for gas-liquid separation is attractive due to its small size and weight.However,very scarce information on the performance of the swirl tube cyclone especially at high operating pressure emulating actual field condition was published in journals.Performance assessment was usually done at a low operating pressure using either air-water,air-fine particle mixtures or dense gas such as SF6.This paper fills the existing gaps and reports the initial findings on the performance assessment of a horizontal swirl tube cyclone for gas-liquid separation operating at a flow rate of 5 MMSCFD at 40-60 bar operating pressure....
2020-09-15 12:28:59浏览：35
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Photoresponse and H2 gas sensing properties of highly oriented Al and Al/Sb doped ZnO thin films
ZnO:Al and ZnO:Al/Sb thin films have been prepared and investigated. The thin films were deposited on Si substrates by the sol-gel method. The structural, optical and electrical properties of ZnO films have been investigated by spectrophotometry, ellipsometry, X-ray diffraction and current-voltage characterizations. It is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate, a high reflectivity in the infrared region and a response to illumination. Furthermore, it has been found that Si/(ZnO:Al/Sb)/Al photodiode is promising in photoconduction device while Si/(ZnO:Al)/Al can be used as gas sensor responding to the low H2 concentrations....
2020-09-15 12:28:59浏览：44
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Use of nitrogen gas in high-speed milling of Ti-6Al-4V
To inhibit chips burning in the high-speed cutting of Ti-6Al-4V, nitrogen gas with 0.7 MPa pressure was ejected at the milling zone. The high speed flowing of nitrogen gas speeds up the chips leaving, and prevents the chips from burning at the same time. By this method the cutting force is reduced. Especially, the temperature increment of the finished surface is smaller than 5 ℃. This prevents the increase of hardness, improves the roughness of the finished surface, and reduces the tools wear. Comparing and analyzing the morphology and color of chips, which are obtained from the high-speed machining of Ti-6Al-4V with and without nitrogen gas ejection, show the action mechanism of nitrogen gas during the high-speed machining of titanium alloy, and it is concluded that nitrogen gas can be used to realize the proper high-speed milling of Ti-6Al-4V titanium alloy....
2020-09-15 12:28:59浏览：31
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Effect of Shading on Gas Exchange of Cotton Leaves Under Conditions of Different Soil Water Contents
Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under onditions of different soil water contents in summer midday. All cotton leaves exhibited similar basic responses to shading, including decreased netphotosynthetic rates, a tendency to decrease in transpiration rates, and increased stomatal conductance and intercellular CO2 concentration. The leaf conductance of 80% shaded and 40% shaded plants increased by 28% and 16.7% compared with no-shaded plants at high water, respectively, but the net photosynthetic rates of 80% shaded and 40% shaded plants declined by 50% and 14.73%, respectively. Results showed that combined effect of soil moisture and shading on photosynthetic and stomatal responses in cotton leaves was very remarkable....
2020-09-15 12:28:59浏览：63
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Effects of magnetic fields on HCFC-141b refrigerant gas hydrate formation
Low-pressure refrigerant gas hydrates have brilliant prospects as a cool storage medium for air-conditioning systems. Intensive effects of some specific magnetic fields on the formation process of HCFC-141b refrigerant gas hydrate are depicted experimentally. Under influence of these specific magnetic fields, the orientation and growth region of gas hydrate are altered; induction time of hydrate crystallization can be shortened extremely, and it can be shortened to 40 min from 9 h; hydrate formation mass can be enhanced considerably, and hydration rate can arrive at 100% in some instances. Meanwhile, the relations of induction time and hydration rate changed with magnetic field intensity are depicted, and some elementary regulations are found....
2020-09-15 12:28:59浏览：75
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Amplification process of a gas electron multiplier simulated by PIC-MCC model
The performance of a single gas electron multiplier (GEM) in pure Xe at an atmospheric pressure is investigated by Particle in Cell-Monte Carlo Collision (PIC-MCC) model.The micro development processes with electrons and ions distributions in space have been revealed.Based on the micro development processes,the macroscopic parameters such as GEM gain and the effective efficiency have also been obtained.The simulation results indicate that after tens of nanoseconds,electrons are collected by the readout electrode while the ions still exist in the gas space for several microseconds.The main signal current is formed by the electrons arriving at the readout electrode,but electrons and ions are also collected by the copper electrodes near the GEM hole and the thin Kapton film boundary.The simulated gain of GEM exponentially increases with the applied GEM voltage.With the PIC-MCC simulations,both the physical amplification and charging mechanisms in the GEM device can be well understood,which is beneficial to the device design....
2020-09-15 12:28:59浏览：65
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Effect of closed-couple gas atomization pressure on the performances of Al-20Sn-1 Cu powders
Al-20Sn-1 Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa.The characteristics of the powders are determined by means of dry sieving,scanning electron microscopy (SEM),optical microscopy (OM),and X-ray diffractometry (XRD).The results show that the powders exhibit a bimodal size distribution and a higher gas pressure results in a broad size distribution.All particles in both cases are spherical or nearly spherical and satellites form on the surface of coarse particles.Dendritic and cellular structures coexist in the particle.With decreasing particle diameter,the secondary dendrite arm spacing (SDAS) decreases and the cooling rate increases.The particles processed under high gas atomization pressure (1.6 MPa) exhibit a lower SDAS value and a higher cooling rate than those of the same size under low gas atomization pressure (1.1 MPa).The XRD results show that the Sn content increases with decreasing particle size....
2020-09-15 12:28:59浏览：71
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Influence of the preheated substrate temperature on the microstructure deposition behavior of the 30
The effects of the substrate temperature on the deposition and microstructure of the 304 stainless steel(SS)cold gas dynamic spraying(CGDS)coatings were investigated.It was found that the higher substrate temperature could increase the deposition rate of the 304 SS particles,even the oxide films existed at the interface.There was a critical oxide film with a thickness of 3-4 μm which could be destroyed by the impacted particles.The micro-hardness and microstructure of the 304 SS coatings under different substrate preheating temperatures were almost the sanle....
2020-09-15 12:28:59浏览：60
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