| 1 | Al_2O_3/Al合金复合材料的蠕变与回蠕变行为显示文摘研究了挤压铸造 Al_2O_3短纤维(体积分数为 15%)增强 Al合金 Al-Si12-Cu1-Mg1-Ni1复合材料的变载荷蠕变和回蠕变行为.结果表明,复合材料在主应力作用下蠕变当载荷突然降低后,表现为瞬态大应变量收缩以及随后的回蠕变.研究表明初始瞬态收缩完全是复合材料的弹性应变,有别于前人采用复合材料或纯金属、合金所得到的数倍于弹性应变结果.实验结果经数值回归得出回蠕变速率,回蠕变应变 =A ln t+C.指数n在任一主应力应变阶段均接近于-1,系数A取决于降载前复合材料积累的主应力蠕变状态,并随降载前主应力蠕变程度的增加而增大,表明复合材料回蠕变行为受到降载前主应力蠕变状态的制约. | 王浩伟 A.Wanner T.Bidlingmaier D.Vogt E. Arzt | 2000 | 金属学报2000，36，11： | 5 |
| 2 | The Role of Information and Knowledge in Achieving Environmentally Sound Farming:A Chinese Case显示文摘The paper analyzes the role of information–knowledge for making farming environmentally friendly,using eutrophication of the main drinking water reservoir of Tianjin,China as a case.The analysis considers information and instruction sources used by farmers in relation to their farming and environmental issues,in particular application of fertilizers,and on this basis it discusses governance and policy measures.The study is interdisciplinary,covering both natural and social sciences,and it is based on quantitative methodology,employing descriptive and multivariate statistical methods.The main findings are:(i)farmers make use of a broad range of information and instruction sources,thereby confirming the claim that eutrophication and hence good farming practices are a“wicked”problem;(ii)the young and the members of the Communist Party are more active than others in using a broad range of information and instruction sources;(iii)different categories of farmers give priority to different information and instruction sources,providing a basis for tailor-made disseminations;(iv)the majority of farmers report receiving clear instructions for using fertilizers,yet half of them conceive using fertilizers correctly as difficult;(v)receiving instructions from other farmers and suppliers cater for high scores on clear instructions;and(vi)farmers are best seen as muddling through different pressures from above and different knowledge bases,and not just willy-nilly responding to top-down policy instructions. | Geir Inge ORDERUD Rolf D.VOGT TAN Hongze LUO Jing | 2017 | Chinese Journal of Urban and Environmental Studies2017，5，2： | 0 |
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