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用固相萃取和气相色谱-质谱法对珠三角某条河流进行了多环芳烃的测定。结果表明水相中多环芳烃的浓度范围介于30.96～357.90 ng/L之间,平均为150.14ng/L。以2环（Nap）和3环（Ace,Acy,Flu,Phe,Ant）为主。说明低分子量的多环芳烃在水相中居于优势地位。颗粒相中多环芳烃的浓度范围介于292.54 ng/g和873.65 ng/g之间,平均为574.32 ng/g。以3环和4环（Fluo,Pyr,BaA,and Chry）为主,高分子量五、六环的多环芳烃比例远远高于水相中的比例。lgKoc与lgKow在本研究区具有良好的相关性（R2=0.554）。 相似文献
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为评估降雨路面径流汞(Hg)污染状况,对南京绕城高速公路马群段11场降雨路面径流进行了监测,分析了汞(Hg)的事件平均浓度(EMC)以及降雨特性对径流中Hg污染的影响.结果表明,不同赋存状态的Hg的污染程度均较为严重,总Hg(THg)、溶解态汞(HgD)和颗粒态汞(HgP)含量分别为0.173~3.347,0.069~0.862和0.104~2.485μg/L.THg的EMC超过了中国《地表水环境质量标准(GB 3838—2002)》中5类水的限值.雨水径流中Hg主要以颗粒态存在,络合态Hg(Hgre,0.250~2.821μg/L)的含量远大于挥发性Hg(Hg0,0.023~0.215μg/L)和活性Hg(Hg2+,0.026~0.359μg/L).各种降雨特性对径流中Hg污染的影响顺序为前期晴天数径流时间降雨历时降雨强度降雨量. 相似文献
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苏州河底泥重金属形态分析 总被引：2，自引：0，他引：2
Nine elements （As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn） in sediment samples at 7 sites （Site 1-7） from Suzhou Creek in Shanghai were analyzed with the Community Bareau of Reference （BCR） （sequential extraction （SE）） protocol and simultaneously extracted metals （SEM）/acid volatile sulfide （AVS） procedure to assess the metal bioavailability and toxicology in this area. The results showed that the BCR extraction can be utilized as an additional tool with the AVS method for assessing the potential bioavailability and toxicity of metals in sediments. Pollution from S5 （Site 5） was more severe than from other sites, especially Pb, Cu and Zn. Among all the sites, more than 80% of the total concentration of Fe existed in the residual fraction, As, Cr, Mn also dominated in the residual fraction （more than 50%）. While Cd, Ni and Zn （more than 35%） were mainly in the non-stable phase. Cu had a strong affinity with oxidizable phase and Pb varied from site to site. The SEM/AVS ratio was less than one in these sediments and results implied that the majority of Zn and Ni （〉 40%） were bound to AVS. In contrast, Pb, Cu and Cd were little bound to AVS due to their low ration of SEM-Pb, Cu, Cd to corresponding total concentration and relatively high Dorewater concentration. 相似文献
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以钢渣及蒙脱石为原料,工业淀粉为添加剂,制备钢渣-蒙脱石颗粒吸附剂并将其做为实验材料,研究了其对水中Pb2+的吸附性能,探讨了影响吸附的因素.研究结果表明:钢渣-蒙脱石颗粒吸附剂在溶液pH为7和吸附反应时间120min的条件下吸附效果最佳.在此环境条件下,吸附剂用量为9.0g/L、对初始浓度为100mg/L的 Pb2+溶液的去除率可达到93%,钢渣-蒙脱石颗粒吸附剂在以上条件下对Pb2+的吸附量为10.3mg/g;钢渣-蒙脱石颗粒吸附剂吸附重金属离子时可用二级动力学方程进行拟合,对Pb2+的相关系数为0.9993;且符合Langmuir方程,其相关系数为0.9929;对Pb2+的理论饱和吸附量为12.61mg/g. 相似文献
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以唐山市公交系统为研究对象,构建网络模型。在L空间和P空间分别研究唐山市公交系统静态网络性质,包括网络的聚类系数、平均路径长度和度分布。结果表明,唐山市的公交网络具有较大的聚类系数、较小的平均路径长度和指数形式的度分布,具有典型的小世界网络的特征。 相似文献
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Response surface methodology （RSM） was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows： ammonium sulfate 0.7498 （10.75 g/L）, glucose 0.9383 （109.38 g/L） and nicotinic acid 0.3633 （7.86 mg/L） with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient （R^2） was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results. 相似文献
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明清时期苏州古市镇的选址,按照地域分布和布局形态,大致可分为三大区域和五种类型。苏州古市镇的选址、形态及其演变,深受地形、河湖分布、农业生产、交通条件、商贸、手工业和经济社会发展等情况的影响和制约。研究苏州古市镇的选址、布局和演变规律,对当今保护古市镇和建设现代小城镇都具有重要的意义。 相似文献
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西江流域有机氯农药含量组成特征及年通量 总被引：1，自引：0，他引：1
刘艳霖 《深圳信息职业技术学院学报》2008,6(4):76-80
用固相萃取和气相色谱法对西江（珠江的主干）进行了为期1a的水相和颗粒相中17种有机氯农药（OCPs）测定。结果表明,水相OCPs的含量范围在2．28～10．21ng／L之间,颗粒物是OCPs的含量变化在20．29-58．74ng／g之间,经过分析得出西江水体中,有机氯农药主要以水相为主,颗粒物中农药所占比例远小于水相中。就OCPs来讲,研究区水质符合国家I类水标准。其来源方面地表径流对此有很大的贡献。西江中六六六类、DDT类和总OCPs的年通量为272．3,164．6,1245．3kg。 相似文献
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Xu YX Li YL Xu SC Liu Y Wang X Tang JW 《Journal of Zhejiang University. Science. B》2008,9(7):558-566
Objective: To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation (SSF). Methods: Statistical methodology including the Plackett-Burman design (PBD) and the central composite design (CCD) was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. Results: Firstly, NaNO3, yeast extract, urea, Na2CO3, MgSO4, peptone and (NH4)2SO4 were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization.Finally, the CCD and response surface methodology (RSM) were applied to determine the optimal concentration of each sig-nificant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by mul-tiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x1 (urea)=0.163 (41.63 g/L), x2 (Na2CO3)=-1.68 (2.64 g/L), x3 (MGSO4)=1.338 (10.68 g/L) and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. Conclusion: By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization. 相似文献
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Interaction Between DEHP and Particulate in a Eutrophic Lake 总被引：2，自引：0，他引：2
Characteristics of interaction between di-2-ethylhexyl phthalate(DEHP) and particulate in a eutrophic lake were studied in this paper. DEHP concentrations ranged from 89.9 to 247 μg/L with an average value of 146 μg/L in subsurface water (SSW) samples, and from 82.0 to 390 μg/L with an average value of 211 μg/L in water surface microlayer (SM) samples. The results indicate that there was only a weak correlation between the DEHP concentrations and suspended particulate material(SPM) concentrations in both SSW and SM,while the significant correlation between DEHP concentrations and chlorophyll a concentrations was found,which suggestes that DEHP was principally bound to phytoplankton in the eutrophic lake. Correlation between DEHP concentrations and total phosphor (TP) concentrations was also found in this investigation. Enrichment factors (EF) of DEHP in SM were in the range of 0.85 to 2.12 with an average value of 1.35..DEHP EFs were significantly related to the enrichment of chlorophyll a in SM. The results suggest that the enrichment of DEHP in SM of this eutrophic lake was mainly due to DEHP accumulation in phytoplankton and was controlled by distribution of phytoplankton between SM and SSW. 相似文献
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The effect of non-reactive powder particle properties on the detergent dry agglomeration process in a high shear mixer was investigated. Three types of micron-scale silica were chosen as the non-reactive fine powders and a semi-solid alkyl ethyl ethoxy sulfate(AES) paste with ultra-high viscosity was chosen as the binder. The granules were characterized using massbased granule size distribution, scanning electron microcopy, and bulk density tests. The results revealed that powder particle size plays a leading role in agglomeration behavior. A decrease in the median particle size results in enhanced dispersion of silica particles in the AES paste binder droplets, which leads to the formation of uniform granules that are slightly affected by compacting forces. Agglomerate quality, using silica with high oil absorption as well as optimum particle size, was satisfactory, and the product exhibited a smaller median particle size, narrower size distribution, and superior anti-caking capacity under the same liquid-to-solid ratio(L/S). 相似文献
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在分析了中国优秀旅游城市和城市人居环境内涵的基础上,运用主成分分析和模糊数学方法,求出长三角经济区16个优秀旅游城市人居环境与旅游业的综合评价得分f（x）和g（x）以及两者的协调度值.研究结果表明：上海、南京、杭州、无锡、绍兴、台州、舟山、泰州和湖州,f（x）＜g（x）,这些旅游城市人居环境水平虽然较高但滞后于旅游业的发展;其他城市f（x）＞g（x）,城市人居环境发展水平高于旅游业的发展水平.协调度方面,上海、南京、杭州和无锡,协调度指数大于0.8,城市入居环境和旅游业处于良好协调阶段;宁波、南通、苏州、常州、嘉兴、扬州、镇江,协调度指数位于0.7 ～0.8之间,处于中级协调阶段;其余城市协调度指数小于0.7,处于初级协调阶段. 相似文献
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Characteristics and sources of polycyclic aromatic hydrocarbons in impervious surface run-off in an urban area in Shanghai, China 总被引：1，自引：0，他引：1
Rainwater and run-off from three kinds of impervious surface in the Shanghai urban area, China were sampled. Polycyclic aromatic hydrocarbons （PAHs） were measured in the samples, and their sources were assessed. The mean sum of the 16 PAH concentrations measured in rainwater and run-offs from ceramic tiles, asphalt roofs, and asphalt roads were 873, 1404, 1743, and 4023 ng/L, respectively. The PAH concentrations found in this study were moderate compared to PAH concentrations found in run-offs in other studies. The main PAH components in the rainwater, roof run-off, and asphalt road run-off samples were 3-ring PAHs, 3-4-ring PAHs, and 4~6-ring PAHs, respectively. Source apportionment results indicated that combustion （47.4%-55.5%） and vehicular emissions （30.5%-33.0%） were the major contributors to PAHs in roof run-off. Vehicular emissions were the most significant contributors to asphalt road run-off （47.2%）, followed by combustion （23.5%）, and petroleum （16.3%）. Vehicular emissions and coal and natural gas combustion are therefore the most significant sources of PAHs in run-off from impervious surfaces in the Shanghai urban area. 相似文献
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研究了地下水水位为2 m时,不同浓度的咸水（1.5、2.5、3.5和4.5 g/L）灌溉对冬小麦株高、叶面积指数、分蘖干重、叶绿素含量的影响.结果表明：当咸水的浓度为1.5 g/L时,平均株高为58.9 cm,平均叶面积指数为5.69,平均分蘖干重为1.41 g,平均叶绿素含量为26.39 mg/L;与1.5 g/L浓度咸水灌溉相比,浓度为2.5 g/L时平均株高、平均叶面积指数、平均分蘖干重和平均叶绿素含量分别减少1.8%、10.5%、10.6%和1.7%;灌溉咸水浓度为3.5 g/L时平均株高、平均叶面积指数、平均分蘖干重和平均叶绿素含量较1.5 g/L时分别减少4.6%、22.8%、22.0%和3.6%;灌溉咸水浓度为4.5 g/L时平均株高、平均叶面积指数、平均分蘖干重和平均叶绿素含量较1.5 g/L时分别减少8.5%、29.0%、27.6%和5.6%.灌溉咸水浓度越高,对冬小麦生长的抑制作用越大. 相似文献
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Some laboratory diffusion tests were conducted with diffusion device to determine the diffusion coefficient of Cr(Ⅵ) ion passing through Dalian red clay samples. The concentrations of Cr(Ⅵ) at different places of the samples were then measured spectrophotometrically after a standing time of 1 000 d. A one-dimensional solute transport equation was used to simulate the transport of Cr(Ⅵ) through clay samples. Back-calculation of diffusion coefficient of Cr(Ⅵ) was made with finite difference method. Parametric... 相似文献
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采用硝酸-过氧化氢-氢氟酸混合酸微波消解法消解烟丝样品,以NH4H2PO4为改进剂,氘灯背景校正横向加热石墨炉原子吸收光谱仪测定铅、镉。方法测试铅、镉的检出限分别为0.735、0.041μg/L,回收率分别为98.81%、92.47%,铅质量浓度范围为3.5～40.0μg/L,镉为0.12～5.0μg/L时相关系数r分别为0.9976、0.9966。方法具有简单、快速、实用性好的优点,可用于实际烟草中铅、镉的测定,结果良好。 相似文献
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以水玻璃和盐酸为原料 ,通过添加表面活性剂制备出高比表面、对高放射性废液中的锆具有高吸附容量的硅胶 .表面活性剂对初级溶胶粒子产生修饰作用 ,限制溶胶粒子的生长 ,但却促使溶胶粒子的连接 .因此 ,表面活性剂起到了无机结构导向剂的作用 ,并且促使溶胶粒子连接成网络结构 .该硅胶的比表面积可达 998m2 /g ,对锆的静态吸附量可达32 .6mg/g ,吸附分配系数为 5 6 .1mL/g . 相似文献