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排序方式: 共有1206条查询结果,搜索用时 31 毫秒
1.
Liqun Lv Yunshan Ge Zhe Ji Jianwei Tan Xin Wang Lijun Hao Zhiwei Wang Mengzhu Zhang Chunjie Wang Haidan Liu 《环境科学学报(英文版)》2020,32(2):155-164
On-road driving emissions of six liquefied natural gas(LNG) and diesel semi-trailer towing vehicles(STTVs) which met China Emission Standard IV and V were tested using Portable Emission Measurement System(PEMS) in northern China.Emission characteristics of these vehicles under real driving conditions were analyzed and proved that on-road emissions of heavy-duty vehicles(HDVs) were underestimated in the past.There were large differences among LNG and diesel vehicles, which also existed between China V vehicles and China IV vehicles.Emission factors showed the highest level under real driving conditions, which probably be caused by frequent acceleration, deceleration, and start-stop.NOx emission factors ranged from 2.855 to 20.939 g/km based on distance-traveled and 6.719–90.557 g/kg based on fuel consumption during whole tests, which were much higher than previous researches on chassis dynamometer.It was inferred from tests that the fuel consumption rate of the test vehicles had a strong correlation with NOx emission, and the exhaust temperature also affected the efficiency of Selected Catalytic Reduction(SCR) aftertreatment system, thus changing the NOx emission greatly.THC emission factors of LNG vehicles were 2.012–10.636 g/km, which were much higher than that of diesel vehicles(0.029–0.185 g/km).Unburned CH_4 may be an important reason for this phenomenon.Further on-road emission tests, especially CH_4 emission test should be carried out in subsequent research.In addition, the Particulate Number(PN) emission factors of diesel vehicles were at a very high level during whole tests, and Diesel Particulate Filter(DPF)should be installed to reduce PN emission. 相似文献
2.
指出了环境监测机构存在的问题,提出环境监测机构体制改革应从3方面考虑:机构改革应实行垂直管理,政,事分开,职能改革应体现环境监测站以环境质量监测为基本职能;内部管理改革需建立以聘任制为基础的用人制度,岗位管理和竞争上岗制度,适当的分配激励机制。 相似文献
3.
研究了乌鲁木剂铁路局系统污水治理污染控制方法及途径,提出了主要污染物为石油类,其最佳治理对策是:确定重点污染单位、污染源、用最低的治理投入,选择斜板隔油气浮工艺治理重点污染和次重点污染部门,得到较好的治理效果,否定盲目追求“零排放”的高投入方案。 相似文献
4.
土地沙漠化监测指标体系的探讨 总被引:20,自引:0,他引:20
评述国内外的沙漠化监测指标体系,根据我国实际情况分析沙漠化监测的主要内容,提出建立沙漠化监测指标体系的原则并设置了监测指标体系. 相似文献
5.
Combating desertification in natural rangelands has recently become a priority in large parts of southern Africa. Rangeland
managers, farmers, scientists, conservationists and land users have been applying a variety of restoration technologies to
address this problem. Bush encroachment, as part of the desertification process, involves the natural replacement of the herbaceous
plant cover by undesirable problem woody species. The active and passive restoration technologies that are applied, are mainly
based on indigenous knowledge and include the chemical, mechanical or manual reclamation of unproductive rangelands, as well
as the combating of woody and alien species encroachment. Indigenous practices and knowledge play a major role in the effectiveness
and success rate of these technologies. This project faces the challenge of bringing together both local and scientific knowledge
in a single user-friendly, computerised Decision Support System (DSS) which is directly accessible by land users to support
them in the process of decision making, concerning the combating of desertification. Case studies from central and northern
Namibia were used to combine qualitative and quantitative data to develop this Decision Support System. The DSS currently
consists of two databases and an expert system, which evaluates the results of land users’ management practices, and provides
easily accessible information and advice for participants in the system, based on the incorporated data. The DSS is also linked
to national and international web sites and databases to offer a wider range of information on technologies concerning agricultural
and conservation practices. 相似文献
6.
7.
笔者从我国包装的现状分析入手,探讨建立绿色包装系统的可行性和必要性,提出建立绿色包装系统的具体措施和实施方案。 相似文献
8.
气候政策研究中的数学模型评述 总被引:3,自引:1,他引:3
按照成本分析和综合分析2个层次,分别介绍了投入产出模型、可计算一般均衡模型、宏观计量经济模型、工程经济模型、动态能源优化模型、能源系统模拟模型、综合评估模型等不同模型方法的特点及其在气候政策分析中的应用。指出可计算一般均衡模型是应用得最为广泛的方法之一。概括了气候政策模型研究的4个发展趋势,包括加强综合评估模型的应用、扩展成本与效益的内涵、注重不同模型之间的比较、强调不确定性分析。结果中国研究现状,分析了当前面昨的问题,认为国内气候政策模型研究与中国在国际气候变化领域的地位仍不相称,强度要进一步加强研究队伍建设、扩展研究领域、跟踪国际研究前沿问题,以便为国家的气候谈判政策提供更有效的科学依据和决策支持。 相似文献
9.
10.
本文阐述了大气污染综合整治规划软件在北票市的实际应用,以北票市大气污染综合整治为实例,建立了大气污染综合整治计算机处理系统,取得了满意的效果. 相似文献