宽板坯凝固前沿轻压下率模型的研究

结合连铸坯凝固规律及轻压下技术改善铸坯中心偏析的冶金原理,建立宽板坯轻压下率理论模型。根据某厂连铸宽板坯实际生产条件,以传热模型计算的铸坯凝固温度数据作为轻压下率模型计算条件,分析拉速、浇注温度、坯壳凝固收缩特性对铸坯轻压下率的影响规律。结果表明,在相同的拉速和浇注温度条件下,铸坯轻压下率沿拉坯方向的分布总体呈减小趋势;拉速较高时的起始轻压下率小于拉速较低时对应的起始轻压下率;拉速与平均轻压下率呈线性递减关系:拉速每升高0.1m/min,平均轻压下率减小0.015mm/m;浇注温度越低,轻压下区起始轻压下率的值越高;浇注温度对平均轻压下率的影响较小,浇注温度每升高10℃,平均轻压下率仅减小0.002 5mm/m;铸坯外部凝固坯壳的收缩对整个轻压下区平均轻压下率的贡献量为20.4%～22.3%。     

浅谈沥青路面常见病害成因及防治对策

文章介绍了沥青路面常见病害的形式及其成因,并简要探讨了病害防治的对策。     

浅谈变压器的安装及调试运行

变压器的安装调试运行必须遵循施工顺序和操作方法,达到现行的国家标准和验收规范的规定,方可运行生产.本文主要探讨变压器安装和调试应注意的问题.     

Concurrent transmission with minimal SR-pair interference in WiMAX mesh networks

Performance of wireless mesh networks can be greatly improved by spatial reuse (SR), therefore, lots of algorithms have been proposed to maximize the number of concurrent transmissions. However, most methods only considered the interference brought by the sender nodes. In this paper, we study the interference model in WiMAX mesh networks and propose a minimal SR-pair interference model to perform concurrent transmissions in both uplink and downlink directions. Simulation results show that our model is more efficient and stable, i.e., it increases the number of concurrent transmissions and its performance is constant and independent of transmission directions. Biography: XIONG Qing(1978–), male, Ph. D., research direction: wireless mesh networks.     

Features of intervertebral disc degeneration in rat’s aging process

Objective: The age-related change is important part of degenerative disc disease. However, no appropriate animal model or objective evaluation index is available. This study aimed to investigate the features of intervertebral disc degeneration in aging process of rats. Methods: 22-month-old Sprague-Dawley (SD) rats were used as spontaneously occurring intervertebral disc degeneration models and 6-month-old rats as young controls. Expression of collagen types II and X was measured by immunohistochemistry. Degenerations of intervertebral discs were scored according to Miyamoto’s method. Numbers and areas of afferent vascular buds were measured. The thicknesses of non-calcified and calcified layers were measured and statistically analyzed. Results: There were less collagen type II expression and more collagen type X expression in the calcified layer of the cartilage endplates and nucleus pulposus in the rats of the aged group than in the young control. There were fewer and smaller afferent vascular buds in the rats of the aged group than in the young control group. The ratio of the non-calcified to the calcified layers in the rats of the aged group significantly decreased, compared with that of the young control group (P<0.01). Conclusion: Rats can spontaneously establish intervertebral disc age-related degeneration. The expression of collagen types II and X, numbers and areas of afferent vascular buds, the ratio of the non-calcified to the calcified layers, and water and glycosaminoglycan contents in the nucleus pulposus are sensitive indexes of intervertebral disc degeneration.     

Joint Funds of National Natural Science Foundation of China： Strategy, Practice and Development

Joint Funds of National Natural Science Foundation of China(NSFC) are initiated by different stakeholders,which aim to play a better guiding role to support basic research in specific areas and directions.They have formed an important part of the national natural science funding system,which is responsible for advancing science and technology in an expanding frontier.The article would briefly summarize the joint funds strategic goals,programs implementation and achievements in the past decade, and provide a perspective on their future development.     

植物RNA病毒寄主因子基因的研究进展

文章综述了植物RNA病毒寄主因子基因的研究进展.     

明清设计制度研究导论

设计制度研究是设计学与社会学的交叉研究,是认识设计、认识物质社会结构的一种视角。明清设计制度研究是在这一命题之下进行的历史学研究,主要对明清涉及设计制度研究的学术成果、原典、图谱及相关研究方法进行整理,寻找对明清设计产生影响的政治动因和文化动因,以便深入分析器以藏礼包含的多重信息及其在古代社会的真实表现,梳理古代中国设计制度的传承方式。     

科技发展与生态文明的关系

国情和世情决定中国最迫切的任务仍是发展和改善民生,科技能很好地解决能源、资源供需矛盾,但以破坏生态环境换取的发展是不可持续的,这就要求科技以更生态、更文明的方式与自然相处,帮助人类文明向生态文明发展.以科学思维和人文思维作指导,奠定生态文明建设的理论基础,激发绿色技术的发展,实现技术的生态转向,让生态文明建设从理论走向实践.技术的生态转向首先要将生态环境纳入到技术使用的考量之中,技术完全参与利用和改造自然的循环过程,其次还要专门发展绿色生态技术.