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181.
Atmospheric corrosion of reference metals in Antarctic sites 总被引:1,自引:0,他引:1
Manuel Morcillo Beln Chico Daniel de la Fuente Elisabete Almeida Günter Joseph Susana Rivero Blanca Rosales 《Cold Regions Science and Technology》2004,40(3):165-178
This paper presents the results obtained at three Antarctic test sites participating in the “Ibero-American Map of Atmospheric Corrosiveness” (MICAT), a project on atmospheric corrosion carried out during the period 1988–1994 at some 70 sites distributed across 12 countries of the Latin-American region, Spain and Portugal. The three Antarctic sites are located near the coastline.The singular climatic characteristics of Antarctic regions are related with the purity of the air, the absence of rainfall and the formation of ice on the metallic surface during an important part of the exposure time. However, electrochemical activity is possible below ice layers. This situation affects the structure and morphology of corrosion product films and the resulting corrosion rates of metallic surfaces. 相似文献
182.
立井钢丝绳罐道的特点及使用 总被引:3,自引:2,他引:1
介绍了钢丝绳罐道的特点,从《煤矿安全规程》的要求出发,考虑钢丝绳罐道的形式、 刚度、定位张紧、布置方式、钢丝绳数目等因素,分析了钢丝绳罐道的选择要点,并指出了钢丝绳罐 道的使用和维护方法。 相似文献
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184.
The deformation behavior of dispersion strengthened copper alloy Cu-Al2O3 was studied by TEM. The results show that nano-scaled dispersed second phase not only increases dislocation density in matrix, but also has an important influence on the dislocation substructure. The presence of fine dispersed Al2 O3 particles results in a uniform and random dislocation distribution in matrix copper and causes the difficulty in formation of dislocation cell structure and the decrease in the amount of cell structure during deformation. Deformation gives rise to much more dislocations and dislocation cells form more difficultly and the decrease in the cell size with the increase of dispersion degree. 相似文献
185.
Preparation of Plate Fe_(60)Co_8Zr_(10)Mo_5W_2B_(15) Bulk Amorphous Alloy and Its Fracture Toughness
肖华星 《武汉理工大学学报(材料科学英文版)》2005,20(2)
1Introduction Duwez[1]synthesizedthefoilAu Siamorphousalloyforthefirsttimewithrapidsolidification,whichinitiatedthepreparationofamorphousalloysintheprocessofalloysolidification,andthereaftertheresearchonamorphousal loysdevelopedrapidly.Since1980s,withthec… 相似文献
186.
When Teachers' and Parents' Values Differ: Teachers' Ratings of Academic Competence in Children From Low-Income Families. 总被引:1,自引:0,他引:1
The authors examined predictors of teachers' ratings of academic competence of 105 kindergarten children from low-income families. Teachers rated target children's expected competence in literacy and math and completed questions about their perceptions of congruence-dissonance between themselves and the child's parents regarding education-related values. Independent examiners assessed children's literacy and math skills. Teachers' instructional styles were observed and rated along dimensions of curriculum-centered and student-centered practices. Controlling for children's skills and socioeconomic status, teachers rated children as less competent when they perceived value differences with parents. These patterns were stronger for teachers who exhibited curriculum-centered, rather than student-centered, practices. The findings suggest a mechanism by which some children from low-income families enter a path of diminished expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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采用透射电子显微镜对不同压下量和再结晶初期的IF钢样品进行了研究.结果表明:无论是在较小形变量下还是在较大形变量下,形变不均匀性是普遍存在的;冷变形程度不同,织构组分不同,TEM形貌也不同;在再结晶的最初期,冷轧的形变组织演变为近乎等轴的亚晶,优先形成{111}〈uvw〉取向的晶核,晶核逐渐吞并周围的形变基体而长大,最终形成再结晶γ-纤维织构. 相似文献
190.
Effects of thermal and mechanical treatments on a titanium-based conversion coating for aluminium alloys 总被引:1,自引:0,他引:1
The influence of mechanical deformation and heating on the protective performance of a chromium-free conversion treatment for aluminium alloys has been assessed by polarisation and AC impedance measurements. Protection is unlikely to be seriously compromised by typical production operations. 相似文献