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91.
东北地区城市大气颗粒物中多环芳烃的污染特征   总被引:10,自引:5,他引:5  
2008年4月至2009年1月期间,在东北三省(辽宁、吉林、黑龙江)设立30个观测点位,研究了东北城市大气颗粒物中PAHs的浓度水平、分布及来源.结果表明,不同季节14种PAHs总浓度的变化范围是16.3 ~712.1 ng/m3,呈冬季高、夏季低的季节变化特征;PAHs组成以4~5环化合物为主,3~4环化合物受温度的影响较大,表现出较强的季节波动;8个城市中抚顺和吉林PAHs污染最重,城市不同功能区中以工业区污染较重;燃煤和机动车尾气是区域PAHs的主要来源.  相似文献   
92.
东北玉米热量指数预测方法研究(Ⅲ)——GM(1,1)预测方法   总被引:2,自引:0,他引:2  
GM(1,1)是开展时间序列环境要素变化趋势预测的有效方法之一。通过对东北地区玉米热量指数的分析,建立了热量指数时间变化趋势的GM(1,1)预测模型,各模型的平均预测精度虽低于逐步回归统计模型,但也都达91%以上,可以应用该模型的预测结果指导农业生产。  相似文献   
93.
China's circular economy is still at the initial stage, whose development has many difficulties and problems requir- ing immediate resolution theoretically and practically. Due to the differences of re...  相似文献   
94.
Understanding how climate change, exploitation and eutrophication will affect populations and ecosystems of the Baltic Sea can be facilitated with models which realistically combine these forcings into common frameworks. Here, we evaluate sensitivity of fish recruitment and population dynamics to past and future environmental forcings provided by three ocean-biogeochemical models of the Baltic Sea. Modeled temperature explained nearly as much variability in reproductive success of sprat (Sprattus sprattus; Clupeidae) as measured temperatures during 1973-2005, and both the spawner biomass and the temperature have influenced recruitment for at least 50 years. The three Baltic Sea models estimate relatively similar developments (increases) in biomass and fishery yield during twenty-first century climate change (ca. 28 % range among models). However, this uncertainty is exceeded by the one associated with the fish population model, and by the source of global climate data used by regional models. Knowledge of processes and biases could reduce these uncertainties.  相似文献   
95.
南通地区位于长江三角洲北翼,其冰后期的环境变化以最大海侵时期为界,之前为海侵期,表现为海水入侵,陆地面积减少。之后海面趋于稳定,长江泥沙在河口地区持续沉积的作用下,表现为南通地区的逐渐成陆过程。利用收集的84个分布于南通地区及附近的钻孔剖面资料,将其按不同厚度的沉积相进行整理,结合前人研究成果,根据不同的数据基础运用IDW(Inverse Distance Weighted)插值对南通地区冰后期沉积厚度分布和环境变化过程分别进行了初步研究。结果表明:南通地区古河谷区是冰后期主要的泥沙沉积区,沉积物厚度、体积和重量大于北翼地区,北翼前缘沉积要大于后缘。冰后期古河谷区沉积泥沙4 8922×108 t,北翼地区沉积泥沙1 0453×108 t,二者之比约为47〖DK〗∶10,泥沙沉积强度之比约2〖DK〗∶1。从冰后期海侵初期到最大海侵时期,再到南通成陆的晚期,南通地区水域面积比例先由622%上升到95%,再缩减到331%,陆地面积比例先由378%缩减到5%,而后又上升至669%。尽管钻孔资料可以为南通地区有历史记载之前的时期提供宏观的环境变化框架,但由于钻孔资料在测年数据及沉积相的划分方面分辨率较低,在表现南通地区历史时期的环境变化方面存在不足,需要结合考古、文物等历史资料和土壤分布等自然地理信息进行更为详细的研究  相似文献   
96.
This paper aims to estimate the effects of changing life style and consumption demands driven by income growth and urbanization on increase of energy requirements in China, and es-timate the impacts of improvement in household consumption on mitigating energy requirements towards 2020, based on input-out-put analysis and scenarios simulation approach. The result shows that energy requirement per capita has increased by 159% for urban residents and 147% for rural residents from 1995 to 2004. Growth in household consumption driven by income growth and urbanization may induce a successive increase in energy require-ments in future. Per capita energy requirements of urban residents will increase by 240% during 2002-2015 and 330% during 2002-2020. Urbanization might lead to 0.75 billion ton of increment of energy requirements in 2020. About 45%-48% of total energy requirements in China might be a consequence of residents’ life styles and the economic activities to support consumption demands in 2020. Under low-carbon life style scenario, per capita energy requirements of urban residents may decline to 97% in 2015 and 92% in 2020 in contrast with baseline scenario. That implies that China needs to pay a great attention to developing green low-carbon life style in order to realize mitigation target towards 2020.  相似文献   
97.
To study the Pu concentration and isotope ratio distributions present in China, the 239+240Pu total activities and 240Pu/239Pu atom ratios in core soil samples from Hubei Province in central China were investigated using Accelerator Mass Spectrometry (AMS). The activities ranged from 0.019 to 0.502 mBq g−1 and the 239+240Pu inventories of 45 and ∼55 Bq m−2 agree well with that expected from global fallout. The 240Pu/239Pu atom ratios in the soil ranged from 0.172 to 0.220. The ratios are similar to typical global fallout values. Hence, any close-in fallout contribution from the Chinese nuclear weapons tests, mainly conducted in the 1970s, must have either been negligible or had a similar 240Pu/239Pu ratio to that of global fallout. The top 10 cm layer of the soil contributes ∼90% of the total inventory and the maximum concentrations appeared in the 2-4 cm or 4-6 cm layers. It is suggested that climatic conditions and organic content are the two main factors that affect the vertical migration of plutonium in soil.  相似文献   
98.
基于投入产出法的中国出口产品隐含碳测算   总被引:6,自引:0,他引:6  
使用投入产出法,利用1999 -2008年中国海关货物出口商品分类数据,研究和测算了中国出口商品中的隐含碳.研究结果显示,中国是隐含碳的出口大国,出口贸易是中国CO2排放量逐年增长的重要原因.1999 - 2008年,我国出口产品中的隐含碳由1999年的3.8亿t上升至2008年的11.9亿t,在此期间,中国CO2年排放量的12% -24%是因生产满足国际市场消费的产品而产生的.中国出口产品中的隐含碳主要集中在5大类行业,分别为:纺织业及服装鞋帽制造业、化学医药制造业、黑色及有色金属冶炼和压延加工业、通用及专用机械设备、电气机械及器材制造业.这5大类行业的出口产品中的隐含碳在中国出口产品的隐含碳总量中占到80%左右.中国出口产品隐含碳的主要流向是美国、欧盟和日本.在实证研究结果的基础上,本文认为国际社会应从生产者负责制和消费者负责制相结合的角度界定各国的碳排放责任和减排目标;同时建议我国应提高生产技术,降低产品的能源消耗强度,并限制能源密集型产业产品的出口.  相似文献   
99.
Abstract

In summer 1997, gelatinous aggregates appeared in the Adriatic Sea, covering large areas of the northern basin. This study deals with the comparison between the biochemical composition of the sedimentary organic matter in summer, 1996 (when no aggregates appeared), and in summer, 1997 (during the appearance of aggregates). the biochemical composition of organic matter in surface sediments (determined in terms of proteins, carbohydrates, lipids, phytopigments and nucleic acids) has been investigated in two areas along the coast of the NW-Adriatic Sea in order to characterize benthic processes during aggregate deposition on the sea floor. During mucilage accumulation, a significant increase of biochemical compounds was observed, and chlorophyll-a and carbohydrate concentrations doubled their concentrations. in contrast, protein concentrations decreased, so that overall biopolymeric carbon content (expressed as the sum of lipid, protein and carbohydrate carbon equivalents) did not display significant differences between sampling periods (1579.3 in June, 1996 1678.8 μgCg?1 and June, 1997). the protein to carbohydrate ratio decreased from 4.9 in June, 1996 to 1.8 in June, 1997. Mucilage production in June, 1997, modified significantly the biochemical composition of the sedimentary OM, thus affecting the potential availability of OM to benthic consumers. We hypothesise that the production of highly refractory composition of the sedimentary OM during mucilage accumulation might have an important biogeochemical implications.  相似文献   
100.
In the present study the concentrations of cobalt, copper, iron, manganese, zinc were analysed and the speciation of copper and zinc performed, with a summer and winter sampling, for two areas in the Northern Adriatic Sea and crossing at the farthest zones of the Po river-sea water interface. Results show that when salinity increases the concentrations of all investigated metals (with the exception of cobalt) present some degree of biogeochemical cycling. Copper is the element whose dissolved phase has the highest importance in metal transport across the salinity gradient. Results of speciation analysis demonstrate that the presence of excess amounts (5-8 fold) of unbound ligands confers a buffering capacity for potential inputs of dissolved metals into the Northern Adriatic Sea. The speciation of both copper and zinc in the dissolved phase was dominated by organic complexation.  相似文献   
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