34 research outputs found
Redistribution of iron during directional solidification of metallurgical-grade silicon at low growth rate
研究冶金级硅低速定向凝固过程中杂质铁的再分布。采用ICP-MS检测铁的浓度,绘制铁在固相、液相、晶界和晶体生长方向上的浓度示意图。铁浓度在固、液相中具有明显差异。依据质量守恒定理,计算得出溶质边界层约为4 mm,铁的有效分凝系数约为2.98×10~(-4)。在低速凝固条件下,铁容易偏析聚集在晶界。在生长方向上,由于低速凝固,铁浓度在硅锭86%高度以下几乎恒定,不完全符合Scheil方程规律。讨论了对流对铁再分布的影响,对流"死区"对铁再分布具有重要影响。Redistribution of iron during directional solidification of metallurgical-grade silicon(MG-Si) was conducted at low growth rate. Concentrations of iron were examined by ICP-MS and figured in solid and liquid phases, at grain boundary and in growth direction. Concentrations are significantly different between solid and liquid phases. The thickness of the solute boundary layer is about 4 mm verified by mass balance law, and the effective distribution coefficient is 2.98×10~(-4). Iron element easily segregates at grain boundary at low growth rate. In growth direction, concentrations are almost constant until 86% ingot height, and they do not meet the Scheil equation completely, which is caused by the low growth rate. The effect of convection on the redistribution of iron was discussed in detail. Especially, the "dead zone" of convection plays an important role in the iron redistribution.Projects(51334004,51204143)supported by the National Natural Science Foundation of China;; Project(2006L2003)supported by the Scientific Technological Innovation Platform of Fujian Province,Chin
An Investigation into the History, the Preset Status and the Problems of Women at Waseda University -From the Viewpoint of Realizing Gender Equal Society-
加快“双一流”建设 实现高等教育内涵式发展(笔谈)
为学习宣传习近平总书记关于教育的重要论述、贯彻落实全国教育大会精神、奋力谱写高等教育事业的新篇章,2018年11月3—4日,由中国高等教育学会主办的\"2018高等教育国际论坛年会\"在浙江宁波隆重举行。本届论坛主题为\"加快‘双一流’建设,实现内涵式发展\"。高等教育内涵式发展是新时期我国高等教育发展的新特征,同时也是新时代对高等教育改革创新提出的新要求。\"双一流\"建设是新时期高等教育改革的适时之举,是实现高等教育内涵式发展的标杆战略,旨在统筹高等教育结构、规模、质量、效益协调发展。\"双一流\"建设需要加强和改进党对高校的领导,完善高校内部治理结构与评价体系,加快推进人才培养模式改革,丰富高等教育教学模式、方式与方法,促进高校学科发展良性化,拓展高等教育国际化发展新渠道,等等。与会领导、专家学者从不同方面探讨、分享了\"双一流\"建设的理念与经验,剖析了高等教育内涵式发展的特征及实现路径,勾画了\"双一流\"建设的未来图景。本刊选发部分发言人的观点摘编,供读者参阅