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81.
系统地介绍了西方国家常用的1种评价环境物品(公共物品)的方法——条件价值法。在大量文献和作者已有研究的基础上,解释了环境物品的特征和价值含义,综述了条件价值法的概念、特点和总体框架内容,分析了该方法中出现的偏差类型,总结了该方法在国际国内的已有应用,提出其应用潜力和应用前景  相似文献   
82.
为全面加强港口危险货物装卸安全管理工作,促进危险货物安全生产形势持续稳定好转,以江苏省危险货物水路运输企业为依托,在文献调研和专家咨询的基础上,提出港口危险货物装卸作业人员安全行为能力影响因素基本模型;以问卷调查的方式评测安全行为能力影响因素,运用SPSS软件对问卷进行信度、效度检验;最后基于问卷检验结果和基本模型,构...  相似文献   
83.
Introduction: It is widely agreed that highway work zones pose significant threats to road users because driving conditions in work zones are quite different from the normal ones, particularly when traffic volumes approach a highway capacity. Therefore, work zone safety is a critical aspect for state agencies and traffic engineers. Method: In the current study, a total of 10,218 crashes that occurred in highway work zones in the state of Washington for the period between 2007 and 2013 were used. Time of day is disaggregated into four subgroups: (1) Morning from 6:00 to 11:00 a.m. (2) Midday from 12:00 to 5:00 p.m. (3) Night from 6:00 to 11:00 p.m., and (4) Late night from 12:00 to 5:00 a.m. Then, four mixed logit models were estimated to account and correct for heterogeneity in the crash data by considering three injury severity levels: severe injury, minor injury, and no injury. Results: The estimation results reveal that most contributing factors are uniquely significant in a specific time of day period, whereas three factors affect injury severity regardless of time of day such as the indicators of not deployed airbag, one passenger vehicle involved in the crash, and rear-end collision. Further, some factors were found to affect injury severity into two or three time periods, such as female drivers that found to decrease the probability of no injury in morning and night time periods, while increasing severe injury outcome in midday time. Conclusions: The effect of time of day on injury severity of work-zone related crashes should be modeled separately rather than using a holistic model. Practical applications: As a starting point, findings of the current study can be used by transportation officials to reduce fatalities and injuries of work zone crashes by identifying factors that uniquely contribute to each time of day period.  相似文献   
84.
2008年汶川大地震给四川省旅游业发展在短期内造成了极大困难,但也给当地遗留了大量的地震遗存,拥有重要的科学考查、科普教育和纪念价值。后重建时代极重灾区面临的旅游发展问题大同小异,虽然开发了许多新项目,但问题并没有从根本上解决。从当地自然环境禀赋各异、少数民族文化开发程度低、旅游商品外来化严重、旅游安全等方面分析了面临的各种问题,提出了具有针对性的对策和建议。  相似文献   
85.
欧盟统计署制定的环境货物和服务部门(environmental goods and services sector,EGSS)统计框架是目前国际认可的专门用于环保产业统计的框架体系,具有全面性、多维性和一致性等特点。本文分析了目前中国环保产业统计概况,初步比较了通过公开的常规统计数据收集EGSS数据和环保产业调查收集EGSS数据的可行性,提出实施"分阶段渐进式"策略逐步引入EGSS统计框架较为可行。  相似文献   
86.
First flush of storm runoff pollution from an urban catchment in China   总被引:13,自引:0,他引:13  
Storm runoff pollution process was investigated in an urban catchment with an area of 1.3 km^2 in Wuhan City of China. The results indicate that the pollutant concentration peaks preceded the flow peaks in all of 8 monitored storm events. The intervals between pollution peak and flow peak were shorter in the rain events with higher intensity in the initial period than those with lower intensity. The fractions of pollution load transported by the first 30% of runoff volume (FF30) were 52.2%-72.1% for total suspended solids (TSS), 53.0%-65.3% for chemical oxygen demand (COD), 40.4%-50.6% for total nitrogen (TN), and 45.8%-63.2% for total phosphorus (TP), respectively. Runoff pollution was positively related to non-raining days before the rainfall. Intercepting the first 30% of runoff volume can remove 62.4% of TSS load, 59.4% of COD load, 46.8% of TN load, and 54.1% of TP load, respectively, according to all the storm events. It is suggested that controlling the first flush is a critical measure in reduction of urban stormwater pollution.  相似文献   
87.
Effect of organic matter and pH on mercury release from soils   总被引:4,自引:0,他引:4  
An investigation was conducted on the effect of organic matter(OM)and pH on mercury(Hg)release from soils.Hg release flux was measured using the dynamic flux chamber(DFC)combined with the Lumex multifunctional mercury analyzer in both laboratory experiment and field monitoring.The results showed that Hg emission from the OM-added soils was apparently low because of the high affinity of OM to Hg,resulting in the reverse order as the amount of OM addition.Meanwhile,Hg release flux from different pH value soils exhibited the same trend for both Hg~(2 )and Hg_2~(2 )treatment,increasing the Hg flux with pH value of soils increasing.The trend of Hg release in the pH dependence experiment has been well in agreement with that from the field test.In addition,Hg release seemed to be related to its species in the soil,the flux from Hg~(2 )-added soil was obviously higher than that of Hg_2~(2 )-added soil by the laboratory experiment.  相似文献   
88.
This is a part of the National Report on Volcanology and Chemistry of the Earth's Interior submitted to the XIXth General Assemblage of IUGG, Vancourver, Canada, 1987, by the China Committee for IUGG. It covers the main achievement in research during the period from 1983 to 1986, on mineralization that can be related to volcanism and that occur in volcanic terrains and probably have an indirect genetic relation with volcanism.  相似文献   
89.
城市污水管网中的涉汞行业,主要包括医疗机构、电器设备及器材制造业、化学原料及化学制品制造业、印刷行业等.明确各行业预处理和排放情况,并对几种典型的涉汞行业排汞与生产使用环节的关系作了分析.北京市高碑店流域包括北京市东城区、崇文区、朝阳区全部和西城区及宣武区的大部分,以高碑店流域为倒,对流域内各涉汞行业进行了统计分类,说明部分行业的汞化合物排放浓度.并提出了城市污水汞污染防治的对策和建议.  相似文献   
90.
1987-1990年四年中我国火山矿床研究中取得下列诸方面的成就:(1)玢岩铁矿的形成决定于基性-中基性并具有高碱低硅岩浆的演化,结晶分异时低氧逸度条件;从世界范围看,构造背景与板块俯冲带或缝合带(包括板内古缝合带)直接或间接有关;实验研究解决了几种特殊矿物组合如“膏包辉”组合等的物理化学条件问题。(2)随着中生代火山岩区金矿床的不断发现,对含矿主岩、基底及矿床类型与分布规律有了进一步的认识。(3)斑岩型矿床分布广泛,除Cu,Mo外,涉及Pb-Zn,Ag,Au,W及Sn矿床,并发现与国外层火山中心地区可以对比的上部为脉状矿下部为斑岩型铜矿的实例;(4)火山岩中铀矿床多形成于晚白垩世之后,受火山盆地攻破火山口构造的明显控制;(5)西北与西南海相火山岩区的块状硫化物矿床中,明确了黑矿型钢及多金属矿床和独立的金矿床的存在,在分类上除了Cu-,Cu-Zn-,Zn-Cu-Pb-及Zn-Pb-型之外,Cu-Pb型在国外很少有报导。(6)从成因或构造角度进行了火山岩区矿床成矿规律成分布规律的探索,注意到基底性质与基底构造的关系,对分布规律挺出了岩浆活动中心迁移造成的分布格局上的超覆和地区的剥蚀深度问题;(7)区分出非金属矿床的两个系列:次生石英岩系列及玻璃岩系列。通过这些研究,在火山岩中发现了一些新的远景区和新的矿床。  相似文献   
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