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961.
962.
963.
Quantifying construction and demolition (C&D) waste generation is regarded as a prerequisite for the implementation of successful waste management. In literature, various methods have been employed to quantify the C&D waste generation at both regional and project levels. However, an integrated review that systemically describes and analyses all the existing methods has yet to be conducted. To bridge this research gap, an analytical review is conducted. Fifty-seven papers are retrieved based on a set of rigorous procedures. The characteristics of the selected papers are classified according to the following criteria - waste generation activity, estimation level and quantification methodology. Six categories of existing C&D waste quantification methodologies are identified, including site visit method, waste generation rate method, lifetime analysis method, classification system accumulation method, variables modelling method and other particular methods. A critical comparison of the identified methods is given according to their characteristics and implementation constraints. Moreover, a decision tree is proposed for aiding the selection of the most appropriate quantification method in different scenarios. Based on the analytical review, limitations of previous studies and recommendations of potential future research directions are further suggested. 相似文献
964.
This study examined the factors associated with financial support in old age from three primary mechanisms-personal savings,family support,and social insurance-to explore the implications for the future development of China’s rural social welfare system.Cross-sectional surveys of 1392 young and middle-aged rural residents were conducted in July and August2012.The results showed that while social insurance was increasingly acceptable,personal savings and family support still had fundamental value.Combining the three mechanisms,the rural old-age welfare system presented nontraditional features.China’s new rural endowment insurance is discussed as a means to address the need for financial support among the rural aging population. 相似文献
965.
城市生活垃圾填埋处理甲烷排放估算及控制途径研究 总被引:2,自引:0,他引:2
随着人口的增长,城市化和经济化发展以及居民生活水平的不断提高,固体废弃物的排放量日益增多,废弃物处理不仅是大气中甲烷的一个重要排放源,而且已成为限制城市化进展和城市经济发展的重大问题之一。固体废弃物填埋处理甲烷的排放量的估算,对准确评估未来气候变化以及应对气候变化所带来的影响具有重要的意义。本文在分析了填埋场甲烷产生影响因素的基础上,估算了2005年-2010年杭州市填埋场甲烷排放量,提出了填埋场甲烷排放控制的对策建议,为杭州市温室气体减排工作提供参考意见。 相似文献
966.
967.
968.
介绍了核电厂止回阀密封性试验中遇到的问题,通过对止回阀的结构进行研究,提出了"等压隔离"概念,通过不同气路保持"等压隔离"装置双密封圈间空间的压力与阀体压力等压,形成"虚拟隔离",从而实现对隔离阀泄漏率的准确测量。重点阐述了等压隔离的结构原理,等压隔离装置的开发及其在隔离阀密封性试验中的应用。通过止回阀的实验室试验,进一步验证了试验方法可靠,测试结果准确。 相似文献
969.
Nine compounds were isolated from the spikes of Prunella vulgaris by various kinds of chromatography. Their structures were established on the basis of spectral analysis as polygalacerebroside (1), ursolic acid (2), β-amyrin (3), quercetin (4), quercetin-3-O-β-D-galactoside (5), β-spinasterol (6), stigmasterol (7), β-sitosterol (8), daucosterol (9). Compound 1 was isolated from this genus for the first time. Phytochemical investigation on the spikes of P. vulgaris provided chemical constituents diversity, which were performed to facilitate further development and utilization of P. vulgaris pharmaceutical resource. 相似文献
970.
Junyi Hu Yu Shen Song Pang Yun Gao Guoyong Xiao Shujun Li Yingqian Xu 《环境科学学报(英文版)》2013,(S1):S32-S35
The decay of wood and other cellulosic materials by fungi cause significant economic loss. The widely used chromated copper arsenate was prohibited for the environmental impact and safety of arsenic and chromium. It was found that natural product hinokitiol (HK) had fungicidal and insecticidal activities, and its toxicity was bearable for the environment. We described the practical synthesis of HK-K salt. According to the GB/T18261-2000 and LY/T1283-1998, wood preservative performance of HK-K salt was tested. The results showed that the best inhibitory concentration of HK-K salt was 50 mg/L, for which the prevention effectiveness on mold is better, the killed value is between 0 and 1, and the corrosion-resistant for wood-rotting fungi is grade A. 相似文献