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211.
随着我国城市化水平的提高,城市交通能源消费占总能源消费的比重逐渐增大,交通方式选择及其影响因素研究引起广泛关注。本研究通过调查南京居民出行交通方式,并通过多项logit模型(multinomial logit model),探究影响居民交通选择的关键因素,为城市交通政策的制定提供科学依据,并根据估算结果分析不同政策下交通方式改变带来的节能减排效应。结果显示:出行特性(如出行距离)、出行者的个人特征(如性别、年龄、职业)与出行者的家庭特征(如是否有私家车,是否有小孩)都对交通方式选择有显著影响。如果通过有效的交通政策引导,使私家车出行转变为轨道交通出行,南京每天大约可减少1573.5吨碳排放。 相似文献
212.
在对国内外港口腹地相互关联研究文献综述的基础上,采用灰色关联分析的定量方法对营口港与辽宁腹地2001--2009年的关联效应进行了分析。实证分析表明:港口港城动态关联效应总趋势逐渐增强,但具有明显的阶段性特征;营口港港口区域一体化进程在关联程度较强的基础上不断强化;营口港辽宁腹地关联发展效应演化具有明显的波动性;自然条件与区位、区域设施与交通、经济水平与社会条件是影响营口港辽宁腹地关联度演化的主要因素。为了促进营口港辽宁腹地经济的快速发展,分别从辽宁腹地、营口城市角度提出相关发展建议:进一步加强政府的政策支持;充分利用自主发展和区域合作推进区域发展;集中发展现代服务业,拓展集装箱业务。 相似文献
213.
现代节庆活动发展迅速,有效塑造了城市旅游形象,促进了城市旅游业的发展。以苏州国际旅游节为例,对历届苏州国际旅游节进行了初步梳理和分析,利用相关数据,对其产生的旅游经济效应、社会文化效应和环境效应进行了综合评价,认为苏州国际旅游节成功塑造了苏州的城市形象,刺激了苏州旅游业发展,有利于苏州旅游资源的有效整合。当前苏州国际旅游节在运营模式、主题创新和当地居民参与度等方面还存在一些问题,对此进行了思考并提出改进建议,以期更好地发挥苏州国际旅游节的整体旅游效应。 相似文献
214.
Release of domestic sewage leads to accumulation of xenoestrogens in holding waters, especially in closed or semi-enclosed waters such as lakes. In the study, the occurrence, distribution, estrogenic activity and risk of eight xenoestreogens were evaluated in Lake Donghu, China. Nonylphenol (NP), octylphenol (OP), and bisphenol A (BPA) were identified as the main xenoestrogens ranging from tens of ng L−1 (in the surface water) or ng g−1 dw (in the suspended particles and sediment) to tens of μg L−1 or μg g−1 dw. The sum of 17β-estradiol equivalents (∑EEQs) ranged from 0.32 to 45.02 ng L−1 in the surface water, 0.53 to 71.86 ng g−1 dw in the suspended particles, and 0.09 to 24.73 ng g−1 dw in the sediment. Diethylstilbestrol (DES) was determined as the main contributor to ∑EEQs followed by NP. The risk assessment showed a higher risk in the surface water than in the suspended particles and sediment in such domestic sewage-holding lake. 相似文献
215.
T. Neuparth R. Capela L. Rey-Salgueiro S.M. Moreira M.M. Santos M.A. Reis-Henriques 《Chemosphere》2013
Despite the extensive maritime transportation of Hazardous and Noxious Substances (HNS), there is a current lack of knowledge on the effects posed by HNS spills on the marine biota. Among the HNS identified as priority, acrylonitrile was selected to conduct ecotoxicological assays. We assessed the acute and subletal effects of acrylonitrile in seabass, followed by a recovery phase to simulate the conditions of a spill incident. The work aimed at testing a broad range of biological responses induced by acrylonitrile. Sublethal exposure to the highest two doses increased the fish mortality rate (8.3% and 25% mortality in 0.75 and 2 mg L−1 acrylonitrile concentrations), whereas no mortality were observed in control and 0.15 mg L−1 treatments. Additionally, important alterations at sub-individual level were observed. Acrylonitrile significantly induced the activities of Catalase– CAT and Glutathione S-Transferase – GST; and the levels of DNA damage were significantly increased. Conversely, Superoxide Dismutase– SOD – activity was found to be significantly inhibited and no effects were found on Lipid Peroxidation– LPO and ethoxyresorufin O-deethylase – EROD – activity. Following a 7 d recovery period, the levels of CAT, GST and EROD fell to levels at or below those in the control. In the 2 mg L−1 group, SOD remained at the levels found during exposure phase. This study has gathered essential information on the acute and subletal toxicity of acrylonitrile to seabass. It also demonstrated that 7 d recovery allowed a return of most endpoints to background levels. These data will be useful to assist relevant bodies in preparedness and response to HNS spills. 相似文献
216.
217.
The aim of this work is (1) to discuss approaches and tools to set management goals using operational indicators for coastal management (i.e., indicators that are easy to measure, understand and predict) and validated predictive models and (2) to discuss remedial strategies for sustainable coastal management regarding water quality and the abundance of fish, waterfowl and large aquatic plants. These approaches are exemplified using data from Ringkøbing Fjord, Denmark, which has undergone two major regime shifts during the last decades. This work discusses the changes taken place during the period from 1980 to 2004 (when there are good empirical data). For Ringkøbing Fjord, which is a very shallow, well-oxygenated lagoon dominated by resuspension processes, we have targeted on the following operational indicators, which are meant to reflect seasonal median values for the entire defined coastal area (the ecosystem scale) and not conditions at individual sites or data from shorter time periods: Secchi depth (as a standard measure of water clarity) and chlorophyll-a concentrations (as a key measure of algal biomass). The operational indicators are regulated by a set of standard abiotic factors, such as salinity, suspended particulate matter (SPM), nutrient concentrations (N and P), coastal morphometry and water exchange. Such relationships are quantified using well-tested, general quantitative models, which illustrate how these indicators are interrelated and how they reflect fundamental aspects of coastal ecosystems. We demonstrate that the regime shift in the lagoon can be modelled and quantitatively explained and is related to changes in salinity and nutrient inflow. A very important threshold is linked to increased salinities in the lagoon. For example, when the mean annual salinity is higher than about 9.5‰, large numbers of saltwater species of clams can survive and influence the structure and function of the ecosystem in profound ways. The model also illustrates the dynamic response to changes in nutrient loading. We have presented several management strategies with the goal of keeping the Secchi depth at 2 m, which would stimulate the growth of higher aquatic plants, which are fundamental for fish production and bird abundance in the lagoon. Given the fact that the Secchi depth depends on many variable factors (temperature, TP-inflow from land, salinity, changes in biomasses of macrophytes and clams, which are accounted for in these simulations), our results indicate that in practice it will likely be very difficult to reach that goal. However, it would be realistic to maintain a Secchi depth of 1.5 m if the variability in salinity is minimized and the mean salinity is kept at about 10.2‰. 相似文献
218.
Spent hydroprocessing catalysts from refineries have been classified as hazardous solid waste by the United States Environmental Protection Agency (USEPA), refiners must find a viable but economical solution to solve this serious environmental issue. Catalyst rejuvenation is an attractive option for minimizing the environmental problems associated with spent catalysts. In this study, a preliminary design for such a process and the corresponding economic analysis are performed to assess the proposed catalyst rejuvenation process for metal-fouled spent catalysts generated in residue hydroprocessing units. The scenarios used in the economic assessment are based on three options of process synthesis and two operator modes. It is found that the option of rejuvenating medium and lightly fouled spent catalyst produced by the refinery will be the best solution for refiners, both environmentally and economically. 相似文献
219.
Crowding and Experience-Use History: A Study of the Moderating Effect of Place Attachment Among Water-Based Recreationists 总被引:1,自引:1,他引:0
Effective recreation resource management relies on understanding visitor perceptions and behaviors. Given current and increasing
pressures on water resources, understanding crowding evaluations seems important. Beyond crowding, however, variables that
possibly relate to or influence crowding are of interest and in particular, place attachment and experience-use history (EUH).
As EUH is related to place attachment and likely affects crowding, this study explored the moderating effect of place attachment
dimensions on the relationships between EUH and visitor crowding evaluations. Water based recreationists at a U.S. Army Corps
of Engineers site were contacted onsite and asked questions related to experience-use history, crowding evaluations, place
attachment, and activity participation. Anglers and campers at the site identified similar crowding perceptions and place
attachments. Only one of eight models tested revealed a moderating effect. Specifically, place identity moderated the relationship
between the total times visited in the past twelve months and expected crowding among anglers. As such, the quest continues
to understand the relationship among these important variables. 相似文献
220.
在明确FMEA分析方法意义的基础上,本文对某装备进行故障模式及影响分析,并得出相应结论,以有助于该装备的研制与使用。 相似文献