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71.
物元理论在区域减灾中的应用 总被引:4,自引:0,他引:4
物元分析是解决矛盾问题的规律和方法,是系统科学,思维科学和数学的交叉学科,本文通过具体的事例分析说明自然灾害研究具有发散性,可扩性,相关性的共轭性的特点,鉴于自然灾害的特性,提出了减灾工作应在传统理论研究的基础上,应用物元理论采用可拓学的方法。 相似文献
72.
A survey was conducted in South Korea to determine residual levels and dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) from meat. Altogether 119 domestic and 164 imported samples of beef, pork, and chicken were examined. The mean levels of PCDD/Fs in upper bound were 0.21, 0.22, and 0.04pg WHO-TEQ/g fat for beef, pork, and chicken, respectively. The low level of PCDD/Fs in chicken probably resulted from the low fat content in the samples used. The samples were separated into domestic and imported products in order to investigate the sources of contamination. PCDFs were the more dominant congeners in domestic beef and were similar to those found from emission of incineration. However, the congener profiles of domestic beef and incineration were difficult to compare because the environmental fate and animal metabolism were involved. The upper bound dietary intake of PCDD/Fs from beef, pork and chicken was calculated to be 0.04pg/WHO-TEQ/kgbw/day. The combined consumption of beef, pork, and chicken was found to be 84.8g per day for a person weighing 60kg and represented 5.7% of their total daily food intake. 相似文献
73.
Reliable evidences that the removal mechanism of hexavalent chromium by natural biomaterials is adsorption-coupled reduction 总被引:7,自引:0,他引:7
For the last few decades, over 200 papers have been published in the Cr(VI) biosorption research field. Most early studies have claimed that Cr(VI) was removed from aqueous phase through an anionic adsorption, but this approach has been lost old original position. It has been newly explained that these findings were misinterpreted due to errors in measuring the concentrations of different chromium species in the aqueous phase, insufficient contact time required for equilibrium and the lack of information about the oxidation state of the chromium bound to biomaterials. Although 'adsorption-coupled reduction' is now widely accepted as the mechanism of Cr(VI) biosorption by natural biomaterials, a number of researchers still believe that Cr(VI) is removed by anionic adsorption onto the biomaterials. Therefore, the objective of this study was to show reliable evidences that the removal mechanism of Cr(VI) by natural biomaterials is 'adsorption-coupled reduction'. Sixteen natural biomaterials were used to study the Cr(VI) biosorption. Not only Cr(VI) but also total Cr in the aqueous phase were analyzed. X-ray photoelectron spectroscope was also used to verify the oxidation state of the chromium bound to the biomaterials. Finally, the removal behavior of Cr(VI) by each biomaterial was described by a kinetic model based on a redox reaction. 相似文献
74.
75.
中国煤电和核电的环境影响与健康风险比较 总被引:1,自引:0,他引:1
将煤电与核电的环境影响和健康风险从全燃料链角度进行比较 ,结果表明 ,煤电燃料链的环境影响和健康风险比核电燃料链大。 相似文献
76.
本文从分析我国传统的经济增长方式入手,通过对资源近视症”的表现及后果的分析,提出西部西地区,特别是西部少数民族地区只有树立全面的资源观,立足优势,面向市场,抓住机遇,合理开发资源和利用资源,才能走出一条符合本民族,本地区实际的可持续发展之路。 相似文献
77.
基于MODIS数据的安徽省植被水分利用效率时空变化及影响因素 总被引:1,自引:0,他引:1
水分利用效率是衡量生态系统碳水循环耦合程度的重要指标。基于MODIS数据、土地覆盖类型数据和气象数据,估算安徽省植被水分利用效率(WUE),采用趋势分析法和相关分析法对安徽省2000~2014年植被WUE的时空格局、变化趋势及影响因素进行研究。研究表明:(1)不同植被类型的WUE年均值差异明显,常绿阔叶林和常绿针叶林的WUE均值较高,分别达到1.66和1.69 gC?mm-1?m-2,而耕地的年均WUE最低,各植被类型的年均WUE按照“常绿针叶林>常绿阔叶林>灌木>草地>落叶阔叶林>针阔混交林>耕地”的顺序递减。植被年均WUE具有较强的空间分异性规律,整体上呈现南北高中间低的趋势,植被WUE的高值区主要分布在大别山区和皖南山区,分布范围与常绿针叶林、常绿阔叶林的分布范围基本一致。(2)安徽省2000~2014年植被WUE年内变化呈现出“增加-减小-增加-减小”的M状“双峰型”趋势,具有明显的季节差异,呈现出春季>秋季>夏季>冬季的特征,各季节植被WUE的均值分别占植被WUE的32.58%、24.91%、29.27%、13.24%。(3)安徽省植被WUE动态变化受到降水影响显著的区域占比3.88%;气温显著影响的区域占比2.19%;降水显著影响的地区主要分布在林地范围内,温度显著影响的地区则位于耕地范围内,降水和气温综合显著影响所占面积最小,为0.11%;而植被WUE受气温和降水影响均不显著占比为93.82%;整体上,安徽省大部分地区的植被WUE变化主要受非气候因素影响。 相似文献
78.
Yeo-Myeong Yun Hang-Sik Shin Chang-Kyu Lee You-Kwan Oh Hyun-Woo Kim 《Environmental science and pollution research international》2016,23(8):7138-7145
Converting lipid-extracted microalgal wastes to methane (CH4) via anaerobic digestion (AD) has the potential to make microalgae-based biodiesel platform more sustainable. However, it is apparent that remaining n-hexane (C6H14) from lipid extraction could inhibit metabolic pathway of methanogens. To test an inhibitory influence of residual n-hexane, this study conducted a series of batch AD by mixing lipid-extracted Chlorella vulgaris with a wide range of n-hexane concentration (~10 g chemical oxygen demand (COD)/L). Experimental results show that the inhibition of n-hexane on CH4 yield was negligible up to 2 g COD/L and inhibition to methanogenesis became significant when it was higher than 4 g COD/L based on quantitative mass balance. Inhibition threshold was about 4 g COD/L of n-hexane. Analytical result of microbial community profile revealed that dominance of alkane-degrading sulfate-reducing bacteria (SRB) and syntrophic bacteria increased, while that of methanogens sharply dropped as n-hexane concentration increased. These findings offer a useful guideline of threshold n-hexane concentration and microbial community shift for the AD of lipid-extracted microalgal wastes. 相似文献
79.
80.