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1.
余强  李元东  余鹏  严磊  王亮 《四川环境》2021,(1):198-202
车载环境γ能谱测量系统探测器是环境γ能谱测量技术领域研究热点。为提高探测效率,缩短测量时间,针对车载环境γ能谱测量系统设计了双NaI(Tl)晶体探测器,并测试了探测器主要性能指标。研究表明,探测器能量分辨率为6.73%,计数稳定性优于4.2%,可识别238U、232Th、40K等核素,可清晰分辨152Eu各能量峰,温度稳定性优于2.93%。可见,该探测器性能优异,具有较强的能量分辨和稳定性,为车载γ能谱测量系统的设计提供了技术基础,也为大体积探测器的设计提供了实验基础,有望在辐射环境监测等领域推广应用。  相似文献   
2.
采用固相萃取法处理水样,气相色谱-高分辨双聚焦磁质谱法测定水中超痕量多氯萘,同位素内标法定量,并对样品前处理条件和仪器条件进行优化。试验表明:方法在0.500 ng/L~500 ng/L范围内线性良好;当取样体积为1 L时,方法检出限为0.005 ng/L~0.01 ng/L;对实际水样进行2个质量浓度水平的加标回收试验,平行测定6次的 RSD为2.7%~8.7%,回收率为70.2%~110%。方法适用性试验表明,水样中复杂的基质对测定无影响。  相似文献   
3.
Based on the China high resolution emission gridded data (1 km spatial resolution), this article is aimed to create a Chinese city carbon dioxide (CO2) emission data set using consolidated data sources as well as normalized and standardized data processing methods. Standard methods were used to calculate city CO2 emissions, including scope 1 and scope 2. Cities with higher CO2 emissions are mostly in north, northeast, and eastern coastal areas. Cities with lower CO2 emissions are in the western region. Cites with higher CO2 emissions are clustered in the Jing-Jin-Ji Region (such as Beijing, Tianjin, and Tangshan), and the Yangtze River Delta region (such as Shanghai and Suzhou). The city per capita CO2 emission is larger in the north than the south. There are obvious aggregations of cities with high per capita CO2 emission in the north. Four cities among the top 10 per capita emissions (Erdos, Wuhai, Shizuishan, and Yinchuan) cluster in the main coal production areas of northern China. This indicates the significant impact of coal resources endowment on city industry and CO2 emissions. The majority (77%) of cities have annual CO2 emissions below 50 million tons. The mean annual emission, among all cities, is 37 million tons. Emissions from service-based cities, which include the smallest number of cities, are the highest. Industrial cities are the largest category and the emission distribution from these cities is close to the normal distribution. Emissions and degree of dispersion, in the other cities (excluding industrial cities and service-based cities), are in the lowest level. Per capita CO2 emissions in these cities are generally below 20 t/person (89%) with a mean value of 11 t/person. The distribution interval of per capita CO2 emission within industrial cities is the largest among the three city categories. This indicates greater differences among per capita CO2 emissions of industrial cities. The distribution interval of per capita CO2 emission of other cities is the lowest, indicating smaller differences of per capita CO2 emissions among this city category. Three policy suggestions are proposed: first, city CO2 emission inventory data in China should be increased, especially for prefecture level cities. Second, city responsibility for emission reduction, and partitioning the national goal should be established, using a bottom-up approach based on specific CO2 emission levels and potential for emission reductions in each city. Third, comparative and benchmarking research on city CO2 emissions should be conducted, and a Top Runner system of city CO2 emission reduction should be established.  相似文献   
4.
For several decades, perfluorooctane sulfonate (PFOS) has widely been used as a fluorinated surfactant in aqueous film forming foams used as hydrocarbon fuel fire extinguishers. Due to concerns regarding its environmental persistence and toxicological effects, PFOS has recently been replaced by novel fluorinated surfactants such as Forafac®1157, developed by the DuPont company. The major component of Forafac®1157 is a 6:2 fluorotelomer sulfonamide alkylbetaine (6:2 FTAB), and a link between the trade name and the exact chemical structure is presented here to the scientific community for the first time. In the present work, the structure of the 6:2 FTAB was elucidated by 1H, 13C and 19F nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. Moreover, its major metabolites from blue mussel (Mytilus edulis) and turbot (Scophthalmus maximus) and its photolytic transformation products were identified. Contrary to what has earlier been observed for PFOS, the 6:2 FTAB was extensively metabolized by blue mussel and turbot exposed to Forafac®1157. The major metabolite was a deacetylated betaine species, from which mono- and di-demethylated metabolites also were formed. Another abundant metabolite was the 6:2 fluorotelomer sulfonamide. In another experiment, Forafac®1157 was subjected to UV-light induced photolysis. The experimental conditions aimed to simulate Arctic conditions and the deacetylated species was again the primary transformation product of 6:2 FTAB. A 6:2 fluorotelomer sulfonamide was also formed along with a non-identified transformation product. The environmental presence of most of the metabolites and transformation products was qualitatively demonstrated by analysis of soil samples taken in close proximity to an airport fire training facility.  相似文献   
5.
荧光素酶报告基因法测定废气中二英类物质   总被引:1,自引:1,他引:0  
研究二噁英类生物检测法的主要目的是简化二噁英类分析流程,并找出快速检测的结果与HRGC-HRMS(高分辨气相色谱-高分辨质谱)结果之间的换算系数,从而可以利用快速检测的结果和换算系数来推算HRGC-HRMS的结果.介绍了CALUX(荧光素酶报告基因法)分析废气中二噁英类物质的原理,并采用该方法分析了我国27个废气样品,以期找出其测定结果与HRGC-HRMS结果之间的换算系数.结果表明,这2种测试方法数据相关性显著,R2为0.994 8,数据间的换算系数为0.379.试验表明,CALUX法具有很好的推广性,如果再适当增加废气样品的数量,对换算系数进行适当的优化,则所得换算系数可推广.  相似文献   
6.
震害预测中建筑物属性信息提取方法研究   总被引:1,自引:0,他引:1  
在编制城市抗震防灾规划工作中,如何得到规划区大量的建筑物的普查资料一直是一个重要的课题。就此,本文提出了一种基于RS技术通过首先旋转高分辨率遥感图像而后搜寻建筑物阴影区有效分割线段来实现大范围建筑物层数信息提取的新方法,并结合高分辨率遥感影像数据和实际建筑物层数信息对提取结果进行分析。结果表明计算模型正确,普适性较强,算法过程简单,所得结果精度满足城市震害预测基础信息的要求,有较大实用价值。  相似文献   
7.
浅谈校园网ARP欺骗攻击与防御   总被引:1,自引:0,他引:1  
ARP欺骗木马病毒是校园网络中经常出现的病毒攻击形式.基于ARP协议的概念和工作原理,并通过分析ARP欺骗的工作原理,提出了几种可行的解决ARP欺骗攻击的实用方法,以达到防范并解决ARP欺骗的目的.参5.  相似文献   
8.
/ The last 20 years have seen the successful application of environmental dispute resolution processes, where people voluntarily negotiate toward mutually acceptable solutions, to many environmental disputes. The effects of contextual influences, such as the number of parties and presence of deadlines, on outcomes are known and frequently described. Less well documented and understood are the interaction processes themselves. This paper draws on two case studies to develop a conceptual framework describing these processes. Disputes associated with management planning for the Bob Marshall Wilderness Complex in the United States and Fitzgerald River National Park in Australia provided the cases. The conceptual framework derived had eight sequential stages: (1) joint definition of problems, (2) uncertainty about what to do, (3) agreement on group procedures, (4) realization of interdependence, (5) enthusiasm about collective possibilities, (6) commitment to working together, (7) consolidation of the group, and (8) implementation of a resolution. The framework provides new insights for managers of public wildlands, especially the need for varying but ongoing managerial involvement in dispute resolution processes. High levels of involvement and influence are essential at the beginning in problem definition and group procedure design and at the end in implementing resolutions. Conversely, agency members must be willing to exert less influence, while still being involved and committed to collective purposes, during the middle stages. Also apparent from the conceptual framework is the importance of developing shared understandings and of allowing sufficient time for understanding to develop, if successful resolution is to be achieved. KEY WORDS: Environmental dispute resolution; Conceptual framework; Public wildlands; Shared understandings; Australia  相似文献   
9.
一个公平的多方的不可否认协议   总被引:2,自引:1,他引:1  
公平的不可否认协议解决了电子商务中信息传输的互相否认问题,使通信各方处于平等的位置。协议对各方都是公平的。该协议是基于组加密方法的,由可靠的第三方产生不可否认证据,数据交互次数少,高效实用。  相似文献   
10.
Environmental disputes arise due to opposing views of various groups about their environmental concerns and their economic or developmental interests. Development and protection of the environment constitute two main contradictory objectives within the sustainable development paradigm, which are often in conflict. The decision support system, GMCR II, which implements the graph model for conflict resolution, is employed to model and analyze an environmental dispute arising over the construction of a new freeway between the Iranian capital, Tehran, and the city of Chalous located in the north of the country. This study demonstrates that the graph model for conflict resolution can be used as a methodology to promote a reasonable balance between economic development and environmental protection from a strategic viewpoint. In addition to systematically modelling the conflict by putting the existing information into proper perspective, it is shown how conflict analysis can be used for comparing alternative scenarios and predicting possible future outcomes. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
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