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111.
Given the key role of biogenic volatile organic compounds(VOCs) to tropospheric chemistry and regional air quality, it is important to generate accurateVOCs emission inventories. However, only a less fraction of plant species, in temperate grassland of Inner Mongolia, has been characterized by quantitative measurements. A taxonomic methodology, which assigns VOCs measurements to unmeasured species, is an applicable and inexpensive alternation for extensive VOCs emission survey, although data are needed for additional plant families and genera to further validate the taxonomic approach in grassland vegetation. In this experiment, VOCs emission rates of 178 plant species were measured with a portable photoionization detector( PID). The results showed the most of genera and some families have consistent feature of their VOCs emission, especially for isoprene, and provide the basic premise of taxonomic methodology to develop VOCs emission inventories for temperate grassland. Then, the taxonomic methodology was introduced into assigning emission rate to other 96 species, which no measured emission rates available here. A systematical emission inventory of temperate grassland vegetation in Inner Mongolia was provided and further evidence that taxonomy relationship can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera to grassland vegetation. 相似文献
112.
根据污染源现场调研结果,结合现有污染控制工艺所能达到的技术水平,建议污水排放标准中As浓度由现国家排放标准的0 5mg/L调整为0 1mg/L;Pb不变为1 0mg/L。大气污染物排放标准中As和Pb不变为1 0mg/L。大气污染物排放标准As和Pb的浓度限值分别是为0 5mg/m3和0 7mg/m3。 相似文献
113.
The iron and steel industry is not only an important foundation of the national economy, but also the largest source of industrial air pollution. Due to the current status of emissions in the iron and steel industry, ultra-low pollutant emission control technology has been researched and developed. Liquid-phase proportion control technology has been developed for magnesian fluxed pellets, and a blast furnace smelting demonstration project has been established to use a high proportion of fluxed pellets (80%) for the first time in China to realize source emission reduction of SO2 and NOx. Based on the characteristics of high NOx concentrations and the coexistence of multiple pollutants in coke oven flue gas, low-NOx combustion coupled with multi-pollutant cooperative control technology with activated carbon was developed to achieve efficient removal of multiple pollutants and resource utilization of sulfur. Based on the characteristics of co-existing multiple pollutants in pellet flue gas, selective non-catalytic reduction (SNCR) coupled with ozone oxidation and spray drying adsorption (SDA) was developed, which significantly reduces the operating cost of the system. In the light of the high humidity and high alkalinity in flue gas, filter materials with high humidity resistance and corrosion resistance were manufactured, and an integrated pre-charged bag dust collector device was developed, which realized ultra-low emission of fine particles and reduced filtration resistance and energy consumption in the system. Through source emission reduction, process control and end-treatment technologies, five demonstration projects were built, providing a full set of technical solutions for ultra-low emissions of dust, SO2, NOx, SO3, mercury and other pollutants, and offering technical support for the green development of the iron and steel industry. 相似文献
114.
作物生长和氮含量对土壤-作物系统CO2排放的影响 总被引:18,自引:3,他引:18
为探讨作物生物学特征对土壤-作物系统CO2排放的影响,本研究基于逐步收割法和静态暗箱-气相色谱技术,以冬小麦和水稻作物为研究对象,采用盆栽和大田试验的方法,在作物生长的主要生育期原位测定了土壤-作物系统CO2排放速率,同时测定了作物生物量和氮含量.研究结果表明:①土壤-作物系统CO2排放在生长季内呈现动态变化,土壤-水稻系统CO2排放高于土壤-冬小麦系统.②作物暗呼吸速率与生物量呈显著线性相关.③作物暗呼吸系数(Rd)的季节变化可以用植株氮含量来描述.冬小麦Rd与N含量的关系可用线性方程Rd=0.0124N-0.0076(R2=0.9879,p<0.001)表示;水稻Rd与N含量的关系可用二次方程Rd=0.0085N2-0.0049NR2=0.9776,p<0.001)表示.④作物根系的参与极大地促进了土壤呼吸.冬小麦生长季土壤表观呼吸CO2平均值为247.2 mg·(m2·h)-1 ,高于未种作物土壤1.78倍,水稻生长季为215.3 mg·(m2·h)-1 CO2,高于未种作物土壤的3.38倍.冬小麦根系呼吸系数大于水稻,其根际呼吸对土壤表观呼吸的贡献高于水稻. 相似文献
115.
116.
目的 基于声发射检测原理,探究一种适用于核电安全壳的泄漏定位方法。方法 首先,开展安全壳结构的声波传播特性研究;其次,基于时频分析,对安全壳泄漏产生的声信号进行滤波预处理,基于分布式传感网络,利用互相关系数曲线,估计不同传感器信号时延;最后,采用双曲线法,对泄漏源进行定位,得到定位观测点,对观测点进行离散系数加权,得到预测泄漏源位置。结果 安全壳上波速平均值为3 026.2 m/s,泄漏声信号的频带主要集中在15~80 kHz,没有明显的时域特征。采用该方法对模拟安全壳上的泄漏源进行定位,平均定位误差为4.31 cm。结论 安全壳上周向和轴向的波速差异不大,可近似认为是各项同性的。基于离散系数加权的互相关时差法定位效果良好,满足安全壳结构泄漏定位需求。 相似文献
117.
118.
北京市二个主要工业区汞污染及其来源的初步研究 总被引:17,自引:2,他引:17
为了调查北京市汞污染状况及其来源,选择二个主要工业区石景山区和朝阳区为研究对象.共采集表层土壤26个,剖面样品4个,对照土壤样品4个,并且在冬季采集降雪样品和枯叶样品,分析汞含量.结果表明,燃煤烟尘排放的汞是北京市汞的主要来源,汽车尾气和化工厂泄漏可使局部汞含量增高,表层土壤中汞含量为007—275mg/kg.土壤剖面中的汞含量在0—100cm土层中均较高,其含量与土壤有机质和碳酸盐含量正相关.降雪中汞在07—37mg/L之间,明显高于背景值,其中大部分吸附在颗粒物上.枯叶中汞主要是从土壤吸收,并且有可能被雨水淋溶出来. 相似文献
119.
120.
Rose Adam Zhang Zhong Xiang 《Mitigation and Adaptation Strategies for Global Change》2004,9(4):477-500
Emissions trading is anattractive candidate for implementinggreenhouse gas mitigation, because it canpromote both efficiency and equity. Thispaper analyzes the interregional impacts ofalternative allocations of carbon dioxideemission permits within the U.S. Theanalysis is performed with the aid of anonlinear programming model for ten EPARegions and for six alternative permitdistribution formulas. The reason thatvarious alternatives need to be consideredis that there is no universal consensus onthe best definition of equity. Advanceknowledge of absolute and relative regionaleconomic impacts provides policy-makerswith a stronger basis for making thechoice. The analysis yields several usefulresults. First, the simulations indicatethat no matter how permits are allocated,this policy instrument can substantiallyreduce the cost of GHG mitigation for theU.S. in comparison to a system of fixedquotas for each of its regions. Interestingly, the welfare impacts ofseveral of the allocation formulas differonly slightly despite the large differencesin their philosophical underpinnings. Also, the results for some equity criteriadiffer greatly from their application inthe international domain. For example, theEgalitarian (per capita) criterion resultsin the relatively greatest cost burdenbeing incurred by one of the regions of theU.S. with the lowest per capita income. 相似文献