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以工程实例说明高层建筑中应用高强混凝土产生早期裂缝的特点,从结构型式,混土原材料,施工工艺等多方面分析成因,提出高强混凝土结构避免产生有害裂缝的各项有效措施。 相似文献
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针对当前工程建设对天然砂大量需求的状况,从资源综合利用的角度研究以人工砂取代部分天然砂在混凝土中的应用很有必要.通过试验,以一定比例的人工砂代替天然砂制作混凝土,并将其工作性能、力学性能与天然砂混凝土进行比较.结果表明,在20%~30%比例替代率的条件下,混合砂混凝土的各种性能优良,可以满足施工要求,用于预拌混凝土的生产. 相似文献
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本文作者首先从水泥混凝土本身的性质着手,结合施工经验,分析了水泥混凝土路面质量与温度的各种关系,并提出了减少温度对路面质量负面影响的方法。 相似文献
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本文结合苏丹麦洛维电站厂房安装间EL260大厅重工业地坪浇筑对高温条件下的无筋高强混凝土浇筑工艺进行了浅要分析。 相似文献
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在室内试验确定出混合料组成配比的基础上,通过振碾法铺筑了乳化沥青-水泥混凝土试验路段。在不同使用时间的现场观测结果表明,在合理的材料配比及适宜的施工工艺下,乳化沥青-水泥混凝土具有较好的路用性能。 相似文献
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市政道路水泥混凝土路面施工既有其特点,也存在路面工程的普遍特性。文章分析市政道路水泥混凝土路面施工工艺,探讨水泥混凝土路面施工质量控制。 相似文献
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创意氛围是创意产业化不可缺少的一环。氛围投资将构建外溢效应的渠道,促进创意知识溢出,于是,创意氛围投资及绩效提升成为财务管理的一个新的领域。本文试图以外溢效应为切入点探讨创意产业的氛围投资及融资管理,从知识管理的角度考察减少创意产业化成本及提升绩效的途径,以抛砖引玉。 相似文献
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航速、横流对艏侧推侧向力的影响 总被引:1,自引:0,他引:1
《江苏科技信息》2019,(32):38-43
文章以艏侧推为研究对象,在浅水拖曳水池试验室测试设备的基础上,开发了一套安装在拖车上可用于研究航速、横流流速对艏侧推水动力性能影响的试验装置,并模拟某工程船的实际使用工况,在浅水池中进行了模型试验研究与机理分析。试验结果分析表明,康达效应的作用导致船体在出流口一侧产生负压,艏侧推产生的侧向力随着航速的增加呈现递减的趋势,在4kn航速下,艏侧推产生的推力为零航速下的54.9%;艏侧推产生的侧向力随着横流流速的增加呈现递减的趋势,这主要是因为一方面横流对船体的作用力增大,另一反面槽道进出口两边压力差发生改变导致的。横流流速与推力方向相反时,3kn横流流速工况下,艏侧推产生的推力为无横流工况下的67.4%;横流流速与推力方向相同时,3kn横流流速工况下艏侧推产生的推力为无横流工况下的53.2%。研究结果为工程船在作业过程中更好地使用艏侧推提供数据支撑。 相似文献
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GUO Shu-hua GAO Zu-bo WANG Hui 《美中经济评论(英文版)》2008,7(8):1-12
This paper applies stepwise regression to analyze the contribution of Yunnan fiscal expenditure of agriculture to agricultural economy growth and per capita annual income on agriculture of rural inhabitants over the period from 1978 to 2006, and uses Granger causality test to examine the relation of fiscal expenditure and per capita annual income of rural inhabitants and the income differential between urban and rural residents. The results suggest that it is the structure of fiscal expenditure on agriculture rather than the scale that has effect on the income of peasants. Because of the deviation of objectives of fiscal expenditure, the expenditure of agriculture could not narrow the income differential between urban and rural inhabitants. 相似文献
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Summary and Conclusions If planners and policymakers are to raise the overall level of performance in an industry by bringing the performance of the least productive enterprises up to that of the most productive enterprises, then obviously both subgroups of enterprises must first be identified. Scholars at TsEMI in Moscow have been using a single technique to measure and rank enterprise productive efficiency, that technique being the estimation of a stochastic CES production frontier. Their technique is not very discriminating about the most efficient enterprises and generates a non-unique ranking of enterprises by productive efficiency scores. Confidence in their analysis could be increased if additional analytical approaches generated similar rankings with, perhaps, greater discriminatory power among the most efficient enterprises.The purpose of this paper has been to compare the Afanas"ev-Skokov results, obtained by estimating a stochastic CES production frontier, with analogous results obtained by estimating a semi-stochastic ray-homothetic production frontier and by using linear programming techniques to calculate a deterministic nonparametric production possibilities set. The rankings and the identities of the most efficient and least efficient enterprises are very similar across the three techniques. This inspires confidence in subsequent efforts to bring the performance of poor performers up toward the level of performance of the good performers.Earlier versions of this paper were presented at the 1988 Atlantic Economic Society Meetings in Philadelphia and the 1988 Allied Social Science Association Meetings in New York. The authors are grateful to M. Afanas"ev for sharing the data, to Johnathan Leightner for his research assistance, to Joe Nowakowski, Bill Pfouts, and Cliff Huang for their helpful comments, and to IREX and the National Science Foundation for their support. 相似文献
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