新式速滑刀的结构特征及新技术特点

对国内速滑运动训练界在新式冰刀使用后的技术认识和运用进行调查、访问,并针对在认识上的一些共性问题,通过对新式冰刀性能和技术的研究分析,提出速滑新技术的一些特征性问题,以求得国内速滑界在广泛共识的基础上,采取相应有效的训练方法,尽快地掌握新技术,迅速提高速滑运动成绩。

预应力钢筒混凝土管(PCCP)结构修复更新技术介绍

预应力钢筒混凝土管(PCCP)在我国的应用已有二十多年历史。随着PCCP使用年限的增加,不可避免地将面临结构性修复等问题,目前国内尚没有成熟的PCCP结构性修复更新技术。总结了北美地区已广泛使用的结构性修复更新技术:移除更换技术、钢绞线修复技术、缩颈钢筒内衬技术和钢管穿插技术,详细介绍了这4种技术的原理、施工步骤、技术特点、优缺点以及适用条件,对4种技术进行对比,并对可用于应急修复的方法进行相关介绍。

磷酸生产工艺浅析及窑法磷酸工艺优化改进构想

磷通常是以磷酸盐矿物的形式存在,其利用须通过化学的方式进行转化,通常最关键的一步是将磷矿石中的磷酸盐转化成磷酸(或单质磷)。简介我国的磷资源储量及磷矿石品位、磷化工产品品类,通过对传统湿法磷酸工艺、热法磷酸工艺及其优缺点的分析,认为目前我国磷化工产业主要存在中低品位磷矿利用率低、磷资源浪费大、能耗高、生产成本高、环境污染严重等问题,而窑法磷酸工艺的深入研究与产业化应用是目前解决上述问题最可行的路径。介绍磷酸生产新工艺--窑法磷酸工艺之反应原理、国内窑法磷酸技术发展状况及存在的问题,提出窑法磷酸工艺在磨粉、配料、成型单元及反应器(回转窑或隧道窑反应器)设计、流程优化等方面的优化改进构想,以及磷酸生产新工艺应具备的技术特点。现阶段有必要加大对包括窑法磷酸工艺在内的磷酸生产新工艺的研究力度,争取早日实现工业化。

Ex-ante Adoption Analysis for Improved Sorghum Varieties in the Lake Zone Tanzania

The objective of this study was to determine the influence of production and consumption characteristics of improved sorghum varieties on farmers＇ adoption decisions. Thirty-four farmers and 231 consumers evaluated five sorghum varieties to determine their preferences. The perceptions of the farmers and consumers were summarized and presented to 100 sorghum farmers to help them choose the best varieties, based on results obtained earlier. Ordered probit models were used to predict their adoption decisions. Results indicated that when adoption is predicted on production characteristics alone the adoption rate was lower than when prediction incorporated both production and consumption characteristics of the sorghum varieties. Therefore, when disseminating new technologies farmers need to be informed about the production as well as the consumption characteristics of the new technologies. The outcomes of this study imply that involving producers and consumers in the generation of new agricultural technologies would potentially increase their adoption rates when they are disseminated. Thus a subsector analytical approach is recommended.