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应用电化学方法研究了碳纤维/环氧复合材料与TC6钛合金、LC4铝合金、30CrMnSiNi2A合金钢的电偶腐蚀行为。在20~60℃温度范围内研究了温度对各偶对的电偶电位及电偶电流的影响。比较了各种紧固件金属材料与碳纤维复合材料构成偶对时的电偶腐蚀性能。 相似文献
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表面处理对TC21钛合金与铝合金和钢电偶腐蚀行为的影响 总被引:3,自引:1,他引:3
通过测定TC21钛合金与铝合金和钢电偶电流的方法,研究了TC21钛合金与铝合金和钢在使用接触时发生电偶腐蚀的敏感性.结果表明:TC21钛合金与铝合金和钢形成的电偶对极易发生电偶腐蚀,不能直接接触使用;对钛合金和铝合金分别进行阳极氧化处理可以在一定程度降低电偶腐蚀敏感性.TC21钛合金与钢形成的电偶对,电偶腐蚀行为与钢的成分有很大关系,对钛合金进行阳极氧化处理,对钢进行镀镉或镀镉-钛处理可以提高表面抗腐蚀性能,降低电偶腐蚀敏感性.当TC21钛合金与铝合金和钢接触使用时,必须采取有效的防护措施. 相似文献
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新型航空T-31钛合金导管连接件在模拟服役环境中的抗腐蚀性能研究 总被引:2,自引:0,他引:2
使用自行研制的航空导管连接件腐蚀试验系统,研究了新型航空T-31钛合金导管连接件在模拟服役环境中的气密性、油压气密性以及应力腐蚀、表面腐蚀等综合性能.对这种钛合金导管连接件在高温盐水溶液浸泡与烘烤循环条件下的表面腐蚀及应力腐蚀行为进行了评价;初步探讨了在模拟服役环境中,这种钛合金发生腐蚀的机理.并比较研究了导管材料1Cr18Ni9Ti与连接件钛合金在6%NaCl水溶液中的电偶腐蚀敏感性.研究发现,T-31钛合金导管连接件在模拟服役环境中只在应力集中处发生轻微孔蚀,在试验应力水平下,无应力腐蚀倾向,具有良好的耐蚀性能;并证明,腐蚀介质通过钛合金阳极化膜层小孔渗入基体对基体造成轻微腐蚀,试验应力水平未造成孔蚀发生处裂纹形核;电偶腐蚀试验进一步说明1Cr18Ni9Ti / T-31电偶对有很小的电偶腐蚀电流,用它们制备的导管及导管连接件能安全地进行偶接. 相似文献
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由于舰船由多种材料构成,当这些结构材料位于同一体系而未使用电绝缘措施时,极易发生电偶腐蚀.通过筛选舰船常用金属材料,对15对异金属偶对开展电偶腐蚀试验,来获取舰船用金属材料的电偶腐蚀特性.结果 表明:TA2与ZTA5作阴极时与其他金属作阴极时相比,阳极腐蚀速率更快,偶合电位较负,且随面积比的增加电偶腐蚀速率呈现加快的趋势;铜合金B10及不锈钢316L电偶腐蚀性相差不大;907与其他金属相连时偶合电位较负,极易发生电偶腐蚀,应注意电绝缘防护.因此钛合金应避免与其他金属直接偶接,907与其他金属相连时必须使用电绝缘防护. 相似文献
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研究了TA28、Ti6321钛合金以及921A、907A船体结构钢在海水环境中的腐蚀特性及电化学行为,对两种钛合金与船体钢之间多面积比条件下的电偶腐蚀行为进行了试验。结果表明,当钛合金与钢直接接触时,钛合金与钢制船体间存在轻微的电偶腐蚀,采用电绝缘措施可以有效控制钛合金对钢制船体的电偶腐蚀。 相似文献
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Kamlesh Goel 《Scientometrics》2002,55(2):243-258
An analysis of gender differences in psychology in India provides quantitative and qualitative assessment of R&D output contributed by psychologists with the indication of the trend of growth, skewness, relatedness, co-authorship pattern of productivity. 相似文献
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The system for Metrology in Chemistry in Germany is described. At the national standards level, a network of high-level chemistry
institutes coordinated by the national metrology institute, PTB, provides the primary references for chemical measurements.
A dissemination mechanism employs chemical calibration laboratories accredited within the framework of the German Calibration
Service (DKD). They act as “multipliers” between the national standards level and the user level by providing the user with
calibration means which are traceable to the SI via national standards. Traceability structures in clinical chemistry, electrochemistry,
elemental analysis and gas analysis are described 相似文献
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Natural radioactivity in drinking water was determined in population-based random study of 472 private wells. The mean concentrations of (222)Rn, (226)Ra, (234)U, (238)U, (210)Pb and (210)Po in drilled wells were 460, 0.05, 0.35, 0.26, 0.04 and 0.05 Bq l(-1), and in wells dug in the soil were 50, 0.016, 0.02, 0.015, 0.013 and 0.007 Bq l(-1), respectively. Approximately 10% of the drilled wells exceeded a radon concentration of 1000 Bq l(-1) and 18% a uranium concentration of 15 microg l(-1). The mean annual effective dose from natural radionuclides for a drilled well user was 0.4 mSv and 0.05 mSv for a user of a well dug in the soil. The effective dose arising from (222)Rn was 75% of the total of all natural radionuclides for drilled well users. As regards long-lived radionuclides, (210)Po and (210)Pb caused the largest portion of the effective dose. The dose arising from (238)U, (234)U and (226)Ra was only 8% of the total of all natural radionuclides. 相似文献
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Radiation Protection Dosimetry 相似文献
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Dominik Gssi 《真空研究与实践》2005,17(4):186-189
Optical film thickness monitoring is more precise than crystal monitoring. The optical measurement makes use of the fact that the intensity of a monochromatic light beam which is reflected on a film will change periodically with increasing film thickness. The measurement is performed at an exchangeable test glass that is positioned beside the substrates and is therefore coated in the same way as the substrates. The accuracy of cut‐off is achieved by a “fit” of a theoretical curve shape to the measured values. Order filters are used to ensure that, at a certain wavelength, higher deflection orders do not influence the measurement when a monochromator grating is used. 相似文献
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In most of its publications, the International Commission on Radiological Protection has highlighted the importance of education and training in radiation protection (RP) for medical exposures. Spain, like other Member States of the European Union, has implemented the Directive and the Guidelines in the medical area. The purpose of this paper is to present the Spanish experience in RP education and training in medicine, the different objectives established according to professional levels, existing regulations and feedback obtained from various RP actions. 相似文献
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Chinedu Nweke Erika Martin Todd Gehr Donald Brophy Daniel Carl 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(2):323-329
Arteriovenous graft (AVG) thrombosis is a frequent cause of graft failure. We evaluated coagulation protein concentrations, platelet function, and viscoelasticity factors in 20 hemodialysis (HD) patients with AVGs. The goal was to determine whether significant differences in protein concentrations, platelet function, and viscoelasticity factors exist among dialysis patients requiring frequent AVG declot procedures vs. those who do not. Twenty HD patients were enrolled: 10 frequent clotters (>3 declots in the previous year) and 10 were nonclotters. Patients on antiplatelets or chronic anticoagulation were excluded. Laboratories were drawn pretreatment and heparinase was added to counteract any potential heparin effect. Coagulation protein concentrations including tissue factor (TF), thrombin/antithrombin III complex (TAT), and prothrombin fragment 1 + 2 (F1+2) were assayed. The time to clot onset was measured by force onset time (FOT). Platelet contractile force (PCF) measured the force produced by platelets during clot retraction, whereas clot rigidity was measured as clot elastic modulus (CEM). FOT, CEM, and PCF were measured by Hemodyne. Both groups had upregulation of the TF pathway, as TF, TAT, and F1+2 levels were similarly increased over baseline levels. Hemodialysis patients with frequent AVG clotting had higher levels of both PCF and CEM compared with nonclotters. Additionally, the frequent clotters had a lower FOT relative to nonclotters, although both were considered in the normal range. Our study suggests that HD patients with recurrent AVG thrombotic events form clots with higher tensile strength compared with HD patients without recurrent graft thrombosis. 相似文献