星型聚合物中间体环硅氧烷核的合成研究

以甲基二氯硅烷、四甲基四乙烯基环四硅氧烷(DVi4)为原料,采用硅氢加成反应合成了星型聚合物的中问体环硅氧烷核,并用红外光谱和核磁共振谱进行了表征.反应的最佳条件是:采用预先活化、反应温度72℃、催化荆与DVi4的量之比为1.0×10-4,反应转化率可达95%,且选择性很好,产物主要为β-加成产物.     

浅谈在线配粉条件下专用粉质量控制

浅述了在线配粉条件下,通过严格生产管理及改良剂应用等相关措施,控制好专用粉质量的措施.包括落实ISO质量管理体系,加强原料的质量控制和预粉、粉路的测定,生产过程中要注意小麦清理与着水、生产设备和现场管理、员工的技术水平因素等.     

基于资源流分析的企业生态补偿机制研究

循环经济作为一种新型的经济范式,成为理论界和实业界共同关注的焦点问题.在循环经济模式下引入了投入产出的资源流管理模型,该模型反映各个过程中资源流的流向和流量,为建立生态补偿机制提供了详细的基础数据,并利用外部环境的完善,推动生态补偿机制在微观领域的实施,从而达到改善企业环境绩效,减少环境污染的目的.     

选煤厂跳汰工艺改造实践

针对选煤厂原有跳汰机技术落后、精煤捞坑跑粗及高灰细泥污染精煤等关键问题,采用SKT高效现代化跳汰机替换原有跳汰机,并用振动弧形筛回收粗煤泥的改造方案;实践证明,改造取得了良好效果。     

龙滩水电站尾水调压井桥机拆除

龙滩水电站尾水调压井施工桥机在完成其施工吊装使命后需要拆除，为保证其完好率，需采取无破坏法整机拆除。介绍了在狭小空间大型设备的整机拆除方法和天锚系统的设计、布局。     

Advances in the management of bronchial asthma

The ultrastructure of rat precorneal tear film was visualized by the quick freezing-freeze substitution (QF-FS) method and the conventional fixative method under the scanning electron microscope (SEM). In the QF-FS method, the eyeballs of rats were quickly frozen with an isopentane-propane mixture cooled by liquid nitrogen applied directly to the eyes. After enucleating the eyes and fracturing the frozen corneas, the corneas were prepared for SEM observation. In contrast to the conventional fixative method, by which the microvilli of the surface epithelial cells could be visualized clearly, a very thin membrane-like structure was observed to cover the corneal surface in the eyes prepared by the QF-Fs method. Between the membrane-like structure and corneal surface, a homogeneous and fine network-like structure was observed. The results suggest that the structure of the tear film might be different from the one we have believed to consist of three layers until now. The QF-FS method is considered to be useful for the morphological study of the precorneal tear film.