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171.
172.
通过长斜井进入正洞施工的特长隧道,往往面临独头通风距离过长、工作面风量不足等问题,造成污染物难以在规定时间排出洞外。以衢宁铁路鹫峰山隧道风仓接力施工通风为依托,采用数值模拟方法研究了风仓长度、隔板长度及风机布置方式对轴流风机通风效率的影响,分析了原压入式通风和风仓接力通风洞内CO运移特性。结果表明,风仓长度从10 m增至25 m时,轴流风机通风效率大幅提高,风仓长度大于25 m时,对轴流风机通风效率的影响不大。设置中隔板会影响空气在风仓内的分流并产生较多旋流,从而降低风机通风效率;轴流风机远离斜井端对称布置,风仓内部风流的引流速度和引流范围最大,风流运动路径最优,通风效率最高。由于压入式通风受限于斜井断面尺寸及现场布置方式,当通风距离超过3 000 m后,无法满足洞内作业环境规定的条件。在正洞与斜井交叉部位设置密封的风仓,形成接力通风,能大幅度延长通风距离,提高通风效率,改善洞内空气质量。 相似文献
173.
The formation of hydrate will lead to serious flow assurance problems in deepwater submarine natural gas transmission pipelines. However, the accurate evaluation model of the hydrate blocking risk for submarine natural gas transportation is still lacking. In this work, a novel model is established for evaluating the hydrate risk in deepwater submarine gas pipelines. Based on hydrate growth-deposition mechanism, the mathematical model mainly consists of mass, momentum and energy conservation equations. Meantime, the model results are obtained by finite difference method and iterative technique. Finally, the model has been applied in the production of deepwater gas field (L Gas Field) in China, and the sensitivity analysis of relevant parameters has been carried out. The results show that: (a). The mathematical model can well predict the hydrate blockage risk in deepwater natural gas pipelines after verification. (b). Hydrate is easily formed at the intersection of horizontal pipeline and vertical riser, and the maximum blocking position often occurs in middle of the riser. (c). The hydrate blockage degree and length of hydrate formation region (HFR) decrease with the increase of gas transport rate. (d). The hydrate blockage degree and length of HFR decrease with the increase of gas transport temperature. (e). The hydrate blockage degree and length of HFR increase with the extension of horizontal pipeline. (f). Injecting inhibitors can effectively inhibit hydrate formation and blockage, but the improvement of transmission measures can significantly reduce the dosage of inhibitor. It is concluded that measures such as increasing gas transportation rate and temperature, shortening horizontal pipeline length, optimizing inhibitor injection point and injection rate can play a safe, economic and efficient role in hydrate preventing and controlling. 相似文献
174.
我国实施西部大开发战略后,西部水资源开发利用问题变得越来越突出.为了弄清楚西部水资源开发利用存在的风险现状,本文在风险概念的基础上探讨了水资源开发利用风险概念和影响因素,并构建了西部水资源开发利用风险评价指标体系.根据水资源系统表现出多模态、突跳和发散的基本突变特征,论述了运用突变理论评价水资源开发利用风险具有一定的可行性,将突变理论引入到水资源开发利用风险评价中,对西部水资源开发利用风险进行评价.首先对各项风险评价指标按照重要性排序,并对各指标值进行无量纲化;然后利用突变模型的归一公式和突变模型的评价准则进行递归运算,最后求出各层指标相对风险值(突变隶属度),将评价结果与风险等级对照,综合判断和分析各层各项指标相对风险状况.计算结果表明:在西部12个省份中,各层指标的风险值差异显著,但是水资源开发利用综合风险值分布在0 66-0.92之间,总体上属于中高度风险水平,12省份风险从小到大排序为:西藏→陕西→重庆→四川→青海→云南→贵州→广西→内蒙→甘肃→新疆→宁夏,这一结果与西部12省份水资源开发利用实际状况相符,可以为西部大开发过程水资源合理有效利用和管理提供风险决策参考依据. 相似文献
175.
Li Yinquan 《中国人口.资源与环境(英文版)》2013,11(3):61-63
Abstract From angles of administrative law and private law, the article analyzes relations between environmental right for citizens and the right to use environmental resources owned by company and enterprise and points out three principles to balancing two relations: A principle of equal protection, a principle that general interest is superior to special interest as well as taking an account for special interest, in specific circumstances, for example, in the circumstance that clashes between environmental and economic interests can not be avoided, policy makers can put an emphasis on more important social interest according after considering weight of each interest. Finally, the article reaches a conclusion that China should establish system of environmental right for citizens from legislative and administrative levels so that a harmonious society can be constructed with guarantee. 相似文献
176.
ABSTRACTGlobal environmental cooperation serves as an important part in the Chinese ideal of building a Community with a Shared Future for all Human Beings. The report of 19th CPC National Congress indicates that China is committed to proactive mitigation under the Paris Agreement and further participating in global environmental governance under the 2030 Agenda for Sustainable Development, and both of which are largely integrated to the Belt and Road Initiative (BRI). BRI are also closely linked with South–South environmental and climate cooperation proposed by China from previous UN summits. Based on shared ideas, intersected agendas, and compatible governance approaches, BRI and the 2030 Agenda for Sustainable Development grow increasingly relevant and they might form synergies based on increasingly interactive relations. In sum, seeking and intensifying the linkages between BRI and 2030 sustainable development goals (SDGs) could address global environmental governance deficits and enhance cooperation among nations. 相似文献
177.
178.
《International Journal of Sustainable Engineering》2013,6(3):231-247
Addressing the root causes of (un)sustainability entails fundamentally changing our ways of living. This requires going beyond technology and behaviour-oriented approaches common under the umbrella of sustainable development (SD). More fundamental change is required to increase the possibility of realizing ecological and psychological well-being. Here, such change is conceptualized as ‘characterological change’. Next to SD another domain is introduced: characterological development (CD). The potential role of design-interventions in CD is explored in this article. Two studies were conducted, a literature study and experts interviews, covering the fields of Design for Sustainable Behaviour, Persuasive Technology, Practice-Oriented Design and Philosophy of Technology. The literature study shows that current research and interventions predominantly fall within the domain of SD, leaving character and related notions largely unaddressed. The expert interviews (n = 10) show a consensus that (design) research concerning the relation between technological artefacts and human character would be valuable. Research challenges and opportunities for design towards ‘living the good life within ecological means’ are discussed. 相似文献
179.
王兴昌 《长江流域资源与环境》1999,8(4):360-364
1997年11月18日,三峡工程大江截流成功,标志着第一期工程结束、进入第二期工程实施阶段。长江三峡水利枢纽具有防洪、发电、航运和供水等巨大综合效益,是跨世纪特大型水利工程。它的建设,不仅对我国能源秘至整个经济布局产生极大的影响,而且对湖北长江经济带的形成与发展具有决定性的意义。 相似文献
180.
陕南化龙山珍稀濒危植物的保护和利用 总被引:6,自引:0,他引:6
傅志军 《长江流域资源与环境》1999,8(1):44-49
化龙山是大巴山系在川陕境内的最高山峰,海拔2917.2m,植物资源丰富,有野生维管植物1977种,隶属186科815属。化龙山是陕西省珍稀濒危植物资源最丰富的地区,共有国家保护的珍稀濒危植物22科30属33种,其中属一级保护1种,二级保护11种,三级保护21种,属濒危2种,稀有14各,渐危17种,珍稀濒危植物古老成分较多,并以第三纪孑遗成分为主单少型属和中国特有属分别是16属和10属。这些珍稀濒危 相似文献