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采用开顶式气室装置研究不同臭氧浓度对3种基因型杨树(‘546’、‘90’和‘84K’)光合作用特征的影响.结果表明,随着O_3浓度的升高,净光合速率(P_n)、蒸腾速率(T_r)、水分利用效率(WUE)、电子传递速率(ETR)、PSⅡ反应中心激发能捕获效率(F'_v/F'_m)、光化学猝灭系数(q P)、PSⅡ实际光化学量子效率(Phi PS2)、叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素总量(Chla+b)和类胡萝卜素(Car)均显著降低,胞间CO_2浓度(c_i)显著升高,气孔导度(G_s)变化不显著.不同基因型杨树各项光合生理指标之间均存在显著性差异,基因型‘546’各项光合指标(除G_s外)与O_3剂量(AOT40,小时O_3浓度大于40nmol·mol~(-1)的累计值)间具有显著的线性相关关系(P0.01),并且光合色素含量随着O_3浓度的升高而显著降低.但高浓度O_3对基因型‘90’和‘84K’光合色素影响不显著.从多数光合特征指标特别是叶绿素总量的O_3剂量线性响应关系来看,基因型‘546’表现出最大的斜率,基因型‘90’次之,基因型‘84K’斜率最小,因而可得知随着O_3浓度升高,三者的臭氧敏感性为‘546’‘90’‘84K’.该研究结果为O_3污染环境下杨树基因型筛选与培育,以及保护杨树免受O_3伤害提供科学依据. 相似文献
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《Journal of Cleaner Production》2007,15(17):1662-1673
The relationship between economy and environmental impacts has been an essential topic in the discussion on environmental problems for a long time. From the 1990s, this relationship has gained a position in environmental policy as well. De-coupling the use of natural resources from economic growth has been set as one of the policy goals in the sixth Environmental Action Programme by the European Commission. In the scientific discussion, the concept of environmental Kuznets curve deals closely with the de-coupling or de-linking phenomenon. Aggregated material flows, on the other hand, have often been considered as a macro-level proxy of environmental degradation. Different methods or approaches have been designed for “sustainability” or “carrying capacity” evaluation as well. The objective of this article is (i) to discuss the possibilities and limitations of using environmental and economic indicators in the sustainability analysis at the macro level, (ii) to present a theoretical framework for the linking analysis including a classification of the degrees of de-linking/re-linking environmental impacts from/to economic growth, and (iii) to give an empirical example by using indicators of direct material flows as a proxy of environmental degradation and by applying the framework into the European Union and its 15 member countries. The results show that the trend in the European Union is a weak de-linking of material flows from economic growth during the years 1980–2000. In other words, material intensity of the economy has generally decreased due to increased efficiency, but the absolute amount of material use has increased, although at a lower rate of increase than economic growth. On the other hand, there is a quite large variation between different EU member countries. However, absolute decrease in the use of materials cannot be found as a continuous trend between the years 1980 and 2000 in any of the studied EU member countries. 相似文献
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矿化垃圾固定床吸附过程和穿透曲线预测 总被引:3,自引:0,他引:3
以轴向扩散模型和恒定图式假设为基础,推导出了适用于预测固定床穿透曲线的积分模型.通过动态循环法对苯酚和对氯苯酚在矿化垃圾中的吸附行为进行了研究,采用Freundlich等温吸附方程描述穿透曲线,并得到了便于应用的代数模型.通过不同条件下固定床实验来确认模型,结果证实模型可以很好地描述穿透曲线.同时讨论了操作参数和矿化垃圾特性对穿透曲线的影响,结果表明,较低的进料浓度和进科流量以及内扩散和轴向扩散的影响都会造成实际穿透曲线与预测穿透曲线之间的偏差. 相似文献
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《Atmospheric Environment. Part A. General Topics》1991,25(8):1577-1590
Diurnal curves of tropospheric ozone are characterized for the areas near coniferous forests in the western U.S. A given day of hourly data can be placed into one of 17 classes of diurnal curves simply by knowing the 24-h mean and coefficient of variation of range, or more precisely, by applying equations derived from our discriminant analysis. The variation among curves is known to be related to theory of ozone formation, scavenging, and transport. Season, latitude, and position relative to source areas affect the form of the diurnal curve. 相似文献
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Jonathan Winsten Sarah Walker Sandra Brown Sean Grimland 《Mitigation and Adaptation Strategies for Global Change》2011,16(8):925-942
The Regional Greenhouse Gas Initiative for the northeastern states of the U.S. allows for terrestrial carbon (C) sequestration
offsets generated by afforestation activities only. This paper estimates the maximum potential quantity and associated costs
of increasing the storage of carbon by afforestation of existing agricultural land in the 11 states of the Northeast United
States. The focus of the work was to describe location, the quantity, and at what cost it would be economically attractive
to shift agricultural production to afforestation to increase carbon storage in the region. Widely available data sets were
used to (1) identify spatially-explicit areas for lower costs carbon offsets and (2) estimate carbon supply curves related
to afforestation of agricultural land over three time periods (10, 20, and 40 years). Carbon accumulation and total carbon
offset project costs were estimated at a county scale and combined to identify expected costs per ton of carbon dioxide equivalents
(CO2e). Large variation in estimated costs per ton of CO2e are driven by varying carbon accumulation potentials and opportunity costs of taking land out of agricultural production,
as well as the duration of the project activity. Results show that the lowest cost carbon offset projects will be in certain
counties of Maine, Vermont, and New York. Pasture land, with lower opportunity costs, generally presents the opportunity for
lower cost carbon offset projects relative to cropland. This analysis estimates that afforestation of pasture land in the
northeast will not become economically attractive until the price rises above 10 per metric tonne (MT) CO < sub > 2 < /sub > e and that up to 583 million MT could be economically sequestered if the price were to rise to10 per metric tonne (MT) CO2e and that up to 583 million MT could be economically sequestered if the price were to rise to 50 per MT CO2e, based on a 40-year project life. With regard to cropland in the northeast, afforestation does not become economically advantageous
for land owners until the price rises above $40 per MT CO2e. It is estimated that up to 487,000 MT could be sequestered from cropland if the price were to rise to $40 per MT CO2e. It is estimated that up to 487,000 MT could be sequestered from cropland if the price were to rise to 50 per MT CO2e, based on a 40-year project life. 相似文献
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Issues in developing a capacity for integrated analysis of mitigation and adaptation 总被引:2,自引:0,他引:2
As policymakers and stakeholders increasingly consider relative merits and complementarities of climate change mitigation and adaptation strategies, it is important to improve analytical capacities to support this process. Because a single analytical approach is unlikely to fit all needs, this paper explores potentials for an integrated analytical framework that incorporates both top–down and bottom–up approaches. 相似文献
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以Monod模型为基准,推导多菌种生物膜内各菌种生物量的推定模型.以东深供水原水生物预处理工程为研究对象,对生物填料进行静态、批量实验,推算生物膜内亚硝化菌(AOB)和硝化菌(NOB)在生物池内的沿程分布规律及其基质限制条件;进行生物膜内AOB和NOB的培养计数实验及反应器系统出水模拟,验证生物量推定结果.结果表明:多菌种生物膜内AOB和NOB生物量的动力学推定,方法简单、可行;生物膜内AOB和NOB的活性生物量沿池长均呈两头低中间高的特殊分布;膜内AOB和NOB的活性生物量分别占相应总生物量的68.2%~74.2%和25.0%~29.9%;以这些活性的AOB和NOB生物量推定结果进行反应器系统出水模拟效果相当理想. 相似文献
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矿区耕地土壤重金属污染评价模型与实例研究 总被引:14,自引:5,他引:14
为对湘南某矿区耕地土壤重金属污染情况作出客观实际的评价,将层次分析理论用于环境评价领域,引入重金属毒性响应系数和重金属在粮食中限量值双重准则,以确定重金属元素之间的权重,并结合加权平均法建立综合评价模型.同时,结合GIS对耕地土壤重金属空间分布、重金属富集特征及综合污染情况进行分析.对该矿区4种重金属Pb、Cd、Cu和Zn的综合污染评价结果表明,该矿区耕地土壤重金属综合污染情况严重,综合污染指数变化范围为1.25~427,属重度污染.因子分析结果表明,4种重金属的来源具有一定相似性,主要来源于矿区有色金属采选冶炼活动.空间分析表明,4种重金属的含量及综合污染的空间分布特征呈明显富集.该评价模型可用于对矿区耕地土壤重金属污染评价的研究,为土壤重金属污染评价提供了新的思路. 相似文献
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文华忠 《安全.健康和环境》2012,12(5):29-31
通过对某企业分析人员在取样过程、分析过程及样品处理过程中的职业危害进行识别与分析,提出了分析人员在作业过程中应采取的个体防护措施及工程上的预防与控制措施。 相似文献
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为考察净化铁锰氨生物滤池内NH4+-N的转化途径,利用氮素计量关系和沿程试验研究了净化铁锰氨生物滤池内产生TNloss(氮损失)的原因和NH4+-N转化途径. 结果表明,净化铁锰氨生物滤池内DO消耗异常,TNloss不守恒,当进水ρ(NH4+-N)平均值分别为1.262、2.296、3.111 mg/L时,NLR(氮损失率)分别能达到7.89%、12.91%、17.73%. 利用硝化反应和CANON(全程自养脱氮)方程式计算得出理论TNloss和TDOC(理论耗氧量),与实际TNloss和ADOC(实际耗氧量)的差值分别小于±0.030、±0.10 mg/L,各阶段NH4+-N 通过CANON途径转化的比例分别为48.58%、60.77%、68.10%,硝化反应和CANON途径共同参与了NH4+-N转化. 沿程试验结果表明,整个试验阶段,NO2--N在滤层中均有积累,并在滤层厚度为10~18 cm内出现NO2--N和NH4+-N共存的现象,进一步证明CANON途径是净化铁锰氨生物滤池内产生TNloss的原因. 相似文献