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41.
Austenite stainless steels (316L, 317L, and 349™) have been coated with 0.6 μm thick SnO2:F by low-pressure chemical vapor deposition and investigated in simulated polymer electrolyte membrane fuel cell (PEMFC) environments. The results showed that substrate steel has a significant influence on the behavior of the coating. Coated 316L showed a steadily increasing anodic current in PEMFC environments, indicating that it is not suitable for this alloy/coating combination. Coated 349™ showed a cathodic current in the PEMFC anode environment, demonstrating its stability in the PEMFC cathode environment. Coated 317L exhibited a stable anodic current after a current peak (at ca. 14 min) in the PEMFC anode environment, and showed an extremely stable low current in PEMFC cathode environment, suggesting the possibility of using SnO2:F coated 317L for PEMFC bipolar plate applications. 相似文献
42.
Pirjo Koskela Merja Teirikangas Ari Alastalo Johanna Forsman Jari Juuti Unto Tapper Ari Auvinen Heikki Seppä Heli Jantunen Jorma Jokiniemi 《Advanced Powder Technology》2011,22(5):649-656
Metallic cobalt nanoparticles were synthesized by hydrogen reduction method. Particles were coated in situ with carbon by adding ethene to reaction flow. Particles were characterized by transmission electron microscopy, energy dispersive X-ray emission, X-ray diffraction, X-ray fluorescence and BET method. The observed cobalt particle size distributions in different cobalt batches produced with unvarying reaction parameters was reproducible: The mean diameter of primary cobalt particle varied only 5% from the mean value of 76 nm in different batches. Increased carbon precursor concentration decreased mean diameter of cobalt particles to 17 nm. The produced nanoparticles were used as filler material in 0–3 type metal–polymer composites. Composite samples with varying filler loading were fabricated with mixing extrusion and injection moulding techniques. The magnetic properties of the fabricated composites were measured up to 1 GHz. In order to analyse the particle distribution in composite matrix and its effect on magnetic properties the microstructure was studied. 相似文献
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Energy harvesting technology may be considered an ultimate solution to replace batteries and provide a long‐term power supply for wireless sensor networks. Looking back into its research history, individual energy harvesters for the conversion of single energy sources into electricity are developed first, followed by hybrid counterparts designed for use with multiple energy sources. Very recently, the concept of a truly multisource energy harvester built from only a single piece of material as the energy conversion component is proposed. This review, from the aspect of materials and device configurations, explains in detail a wide scope to give an overview of energy harvesting research. It covers single‐source devices including solar, thermal, kinetic and other types of energy harvesters, hybrid energy harvesting configurations for both single and multiple energy sources and single material, and multisource energy harvesters. It also includes the energy conversion principles of photovoltaic, electromagnetic, piezoelectric, triboelectric, electrostatic, electrostrictive, thermoelectric, pyroelectric, magnetostrictive, and dielectric devices. This is one of the most comprehensive reviews conducted to date, focusing on the entire energy harvesting research scene and providing a guide to seeking deeper and more specific research references and resources from every corner of the scientific community. 相似文献
45.
MECHANISM OF SLOW CRACK GROWTH AND STRESS CORROSION CRACKING IN AUSTENITIC STAINLESS STEEL 总被引:1,自引:0,他引:1
通过金相跟踪观察、力学测量及断口分析,研究了奥氏体不锈钢氢致开裂和应力腐蚀的机理.结果表明,无论是不稳定型(321)还是稳定型(310)奥氏体不锈钢,电解充氢时先产生塑性变形,当它发展到临界状态时就导致氢致裂纹的形核.但在42%MgCl_2沸腾溶液中应力腐蚀时,裂纹的形核和滞后塑性变形无关.两种(321)輿氏体不锈钢应力腐蚀的门槛值K_(ISCC)远比严重充氢时氢致开裂的门槛值K_(IH)要低.两者的断口形貌也不同,应力腐蚀是解理断口,且和K_I无关.而氢致开裂断口和K_I有关,K_I高是韧窝,K_I低则获得准解理断口.实验表明,氢在奥氏体不锈钢应力腐蚀(沸腾MgCl_2介质)过程中并不起主要作用. 相似文献
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遥感模糊图像分割与像元分析 总被引:6,自引:0,他引:6
卫星遥感对地观测获取的图像信息其像元的数据往往是多种地表成分的复合,因此地表反射辐射反映在像元上带有一定的模糊性,基于模糊数学的理论和方法,同时利用了TM(1,2,3,4,5,7)六个波段的数据信息,对一幅图像进行非监督分割,并用模糊算法对单个像元所隶属的各聚类中心的成分进行了数值分析,结果显示出尽管分割后一些像元属同一类别,但其复合成分则不尽相同,该方法对于TM像元分析精度的可靠性有待地面工作的 相似文献
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Heikki Keinnen Heli Talja Rauno Rintamaa Kari Trrnen Ralf Ahlstrand Pekka Nurkkala George Karzov Boris Timofeev Alexander Blumin 《Nuclear Engineering and Design》1995,158(2-3)
A joint pressure vessel integrity research programme involving three partners is being carried out during 1990–1995. The partners are the Central Research Institute of Structural Materials “Prometey” from Russia, IVO International Ltd (IVO) from Finland, and the Technical Research Centre of Finland (VTT). The main objective of the research programme is to increase the reliability of the VVER-440 reactor pressure vessel safety analysis. This is achieved by providing material property data for the VVER-440 pressure vessel steel, and by producing experimental understanding of the crack behaviour in pressurized thermal shock loading for the validation of different fracture assessment methods. The programme is divided into four parts: pressure vessel tests, material characterization, computational fracture analyses, and evaluation of the analysis methods. The testing programme comprises tests on two model pressure vessels with artificial axial outer surface flaws. The first model vessel had circumferential weld seam at the mid-length of the vessel. A special embrittling heat treatment is applied to the vessels before tests to simulate the fracture toughness at the end-of-life condition of a real reactor pressure vessel. The sixth test on the first model led to crack initiation followed by arrest. After the testing phase, material characterization was performed. Comparison of calculated and experimental data generally led to a good correlation, although the work is being continued to resolve the discrepancies between the measured initiation and arrest properties of the material. 相似文献
50.