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71.
将Ecotect软件应用到建筑玻璃幕墙光反射影响评价中,应用结果表明,Ecotect软件能准确地确定建筑玻璃幕墙反射光的影响范围,且能准确地确定幕墙遮阳设施或周围建筑的遮挡效果,这可大大加强建筑玻璃幕墙光反射影响评价的准确性.另外,Ecotect软件还可准确地分析出受影响的敏感目标或敏感目标受照反射光的来源,这可使幕墙设计者有针对性对受影响敏感目标或对敏感目标产生反射光影响的建筑玻璃幕墙立面采取预防控制措施,来降低或者消除光反射,从而从源头上减少或消除幕墙反射光对周围环境敏感目标的影响.  相似文献   
72.
为了开发无尾矿、少尾矿提钒工艺,对贵州镇远江古钒矿实验室扩大试验流程产生的尾矿进行资源化利用研究,尾渣物质组成研究表明:提钒尾渣的主要化学成分为二氧化硅,主要矿物为石英,尾渣放射性检测结果高于建筑物主体墙材中放射性指标的要求,不能直接应用于建筑主体材料.经用尾渣烧成水泥试验结果表明:尾渣烧成的水泥熟料基本化学成分、物理性能测试结果符合GB/T 21372-2008硅酸盐水泥熟料要求.  相似文献   
73.
Mercury(Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations(PNECs) for Hg(Ⅱ) and methyl mercury(Me Hg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10-3μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms,and their potential ecological risk should be respectively evaluated on the basis of mercury species.  相似文献   
74.
Diurnal air samples were collected from the E-waste dismantling region Guiyu and the underwear industry region Chendian. This was the first report to present the diurnal variation of PBDEs in the atmosphere. The average concentrations of 11 PBDE congeners were 11,742 pg m−3 in the daytime, and 4830 pg m−3 at night in Guiyu, while the concentrations were lower in Chendian with 376 pg m−3 in the daytime, and 237 pg m−3 at night. BDE-209 accounted for 22% and 31.3% of the total PBDEs in Guiyu and Chendian, respectively. The diurnal variation trends of BDE-47, -99, -153, -183, and -209 were also analyzed in detail in the two regions.  相似文献   
75.
以硫酸钛为原料采用水热法制备了掺Fe3+TiO2晶体粉末,采用X射线衍射仪(XRD)对样品的结构进行了表征。在可见光条件下,用溴酚蓝、甲基绿、甲基蓝、孔雀石绿、甲基紫和碱性品红等6种典型三苯甲烷类化合物为目标降解物,研究了以自制的掺Fe3+TiO2晶体粉末对它们的催化降解作用。实验结果表明,制备的掺Fe3+TiO2晶体属于锐钛矿型。6种化合物的光催化降解反应遵循拟一级动力学规律,且可用Langmuir-Hinshelwood(L-H)动力学模型描述,其表观反应速度常数(k)的大小顺序为:溴酚蓝〈甲基绿〈甲基蓝〈孔雀石绿〈甲基紫〈碱性品红,大小变化次序与其半衰期t1/2成反比,并从分子结构上对它们的降解规律进行定性解释。  相似文献   
76.
在好氧反应器中,将海泥通过海水和营养物质培养成新型的活性污泥,在处理含盐废水时有较好的活性和沉降性能,对这种新型的活性污泥我们称其为海洋活性污泥。通过10周的培养,海泥的污泥体积指数(SVI)从最初的19 mL/g升高到70 mL/g,对有机废水处理12 h后高锰酸盐指数(CODMn)降解率达到90%,氨氮降解率达到45%。在污泥培养时,营养物质投加频率为一日一次最有利于污泥的培养,又葡萄糖比淀粉更有利于污泥的培养。对于含盐有机废水的处理,海洋活性污泥也比传统活性污泥有优势,甚至对于含盐量6%的高盐有机废水,处理12 h后能达到CODMn降解率达为70%,氨氮降解率达到30%。当NaCl浓度高于6%,海洋活性污泥仍具有一定的活性,但仍能观察到明显的抑制作用。此外,海洋活性污泥具有比传统活性污泥更强的盐度变化抗性,甚至在低盐度下盐浓度变化时,海洋活性污泥的氨氮降解稳定性也优于传统活性污泥。  相似文献   
77.

Introduction and purpose

The objective of this study is to determine children??s blood lead levels and identify sources of lead exposure. Childhood lead exposure constitutes a major pediatric health problem today in China. A blood lead screening survey program for children in the age group of 2?C12?years residing in Pearl River Delta region, south of China, was carried out from Dec 2007 to Jan 2008.

Methods

Blood lead levels and lead isotope ratios of a total of 761 participants were assessed by inductively coupled plasma mass spectroscopy. Measurements of urban environmental samples for source identification of children lead exposure were also performed.

Results and conclusions

The geometric mean value of the children??s blood lead levels was 57.05???g/L, and 9.6% of them were higher than 100???g/L. The blood lead levels were still much higher than those in developed countries. Based on the data of environmental lead source inventories, lead isotopic tracing revealed that there is about 6.7% past used gasoline Pb embedded in Shenzhen residential dust and about 15.6% in Guangzhou dust, respectively.  相似文献   
78.
Tan J  Cheng SM  Loganath A  Chong YS  Obbard JP 《Chemosphere》2007,68(9):1675-1682
Although the use of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) has been prohibited in Singapore since 1980, OCPs and PCBs still can be detected in the environment and represent a potential threat to public health. In this study, OCPs and PCBs were measured in house dust samples collected from 31 homes across the island-state of Singapore. Organochlorine pesticides, such as hexachlorocyclohexanes (HCHs), chlordanes and dichlorodiphenyltrichloroethanes (DDTs) were tested, with a range of 相似文献   
79.
微波辐照热解废印刷电路板产物的分析研究   总被引:4,自引:0,他引:4  
为了减少电子废弃物对环境的危害,实现其资源化回收利用,研究了微波辐照热解废印刷电路板的效果,并采用红外光谱、气相色谱质谱和X荧光光谱等方法对热解产物的组成及性质进行了分析.结果显示:微波热解得到的气体、液体、固体的产率分别为7%~33%、26%~45%、31%~51%,其中气体主要由CO、CO2、H2及有机烃类组成,可燃性气体占70%(体积分数)左右,可作为燃料气加以利用;液体分为水相及油相,经常压蒸馏后得到的120~250 ℃馏分主要为单酚化合物,苯酚高达50%(质量分数)左右,甲基苯酚和邻甲基苯酚为25%(质量分数)以上,是良好的化工原料;固体中除炭外,还含有许多金属如铅、锡和铜等,可以回收利用.说明微波热解技术处理电子废弃物可实现资源化回收利用.  相似文献   
80.
Polybrominated diphenyl ethers in house dust in Singapore   总被引:8,自引:0,他引:8  
The use of polybrominated diphenyl ethers (PBDEs) as flame retardants in Singapore is not strictly regulated; therefore these compounds can be readily found in furniture, electronic devices, and building materials. This study was the first of its kind to be conducted in Singapore to measure concentrations of PBDEs in house dust. Samples were collected from 31 homes in various locations across the island-state of Singapore, and a total eight PBDEs congeners were measured. PBDEs were detected in all 31 dust samples and the number of BDE congener detected per home ranged between 3 and 8. The most abundant BDE congeners found were BDE 47, 99 and 209, with a median value of 20 ng g(-1) dust, 24 ng g(-1) dust and 1000 ng g(-1) dust, respectively. BDE 209 contributed 88% to the median of all the congeners, and BDE 47 and 99 contributed 1.8% and 3.5%, respectively. Different congener profiles were observed between this and studies conducted elsewhere, which is consistent with the use of different commercial PBDE around the world. No significant correlations between PBDE dust levels and residential characteristics (number of TVs and computers, floor area or flooring material) were observed. The daily intake of PBDEs via the inhalation pathway was estimated. House dust may be regarded as the most important exposure route of PBDEs for children.  相似文献   
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