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61.
62.
采用固相萃取-超高效液相色谱串联质谱法测定环境水样中25种磺胺类和喹诺酮类抗生素,通过优化试验条件,使方法在2.00μg/L~200μg/L范围内线性良好,方法检出限为1.01ng/L~2.85ng/L,7次测定结果的RSD为2.3%~8.0%。将该方法用于自来水和地表水测定,结果均为未检出,高、低质量浓度水平的加标回收率为61.2%~102%。 相似文献
63.
采用固相萃取/高效液相色谱-三重四级杆质谱法同时测定医疗废水中的20种超痕量抗生素残留,通过优化试验条件,使方法在100μg/L~100μg/L范围内线性良好,方法检出限为024ng/L~122ng/L。空白水样和实际水样3个质量浓度水平的加标回收率分别为80.2%~108%和75.8%~114%,6次测定结果的RSD分别为2.4%~8.4%和1.7%~8.1%。将该方法用于测定重庆市2家三甲医院医疗废水中的超痕量抗生素残留,结果有11种抗生素检出,其余均为未检出。 相似文献
64.
Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks. 相似文献
65.
Akira KONDO Esrom HAMONANGAN Satoshi SODA Akikazu KAGA Yoshio INOUE Masaharu EGUCHI Yuta YASAKA 《环境科学学报(英文版)》2007,19(6):709-713
Total suspended particulate mater (TSP) concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum (Al), sodium (Na), iron (Fe), lead (Pb), potassium (K), zinc (Zn), titanium (Ti), manganese (Mn), bromine (Br), copper (Cu), chromium (Cr), nickel (Ni), and vanadium (V) were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles. 相似文献
66.
WANG Hai-ling FEI Zheng-hao CHEN Jin-long ZHANG Quan-xing XU Yan-hua 《环境科学学报(英文版)》2007,19(11):1298-1304
The adsorption behavior of p-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature.Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm.The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest,which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid.The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid.Thermodynamic studies suggested the exothermic,spontaneous physical adsorption process.Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step. 相似文献
67.
Naveen K. Shrivastava Shashikant B. Thombre Kailas L. Wasewar 《International Journal of Green Energy》2016,13(2):213-228
In order to understand the complex transport phenomena in a passive direct methanol fuel cell (DMFC), a theoretical model is essential. The analytical model provides a computationally efficient framework with a clear physical meaning. For this, a non-isothermal, analytical model for the passive DMFC has been developed in this study. The model considers the coupled heat and mass transport along with electrochemical reactions. The model is successfully validated with the experimental data. The model accurately describes the various species transport phenomena including methanol crossover and water crossover, heat transport phenomena, and efficiencies related to the passive DMFC. It suggests that the maximum real efficiency can be achieved by running the cell at low methanol feed concentration and moderate current density. The model also accurately predicts the effect of various operating and geometrical parameters on the cell performance such as methanol feed concentration, surrounding temperature, and polymer electrolyte membrane thickness. The model predictions are in accordance with the findings of the other researchers. The model is rapidly implementable and can be used in real-time simulation and control of the passive DMFC. This comprehensive model can be used for diagnostic purpose as well. 相似文献
68.
Birinchi Bora Arun Kumar O. S. Sastry Renu Dahiya Manander Bangar Takumi Takashima 《International Journal of Green Energy》2016,13(6):580-584
The effect of air mass (AM) on the performance of multi-crystalline silicon (m-Si), amorphous silicon (a-Si), and hetero-junction with intrinsic thin layer (HIT)-technology-based photovoltaic (PV) modules are evaluated for representative day of four seasons during the year 2011 for composite climate of India. To find the best performing PV module technology with respect to AM at the site, annual energy yields and performance ratio against different AM bands (AM 1–4.5) are plotted. It is found that HIT modules perform better than m-Si and a-Si at each AM band. Annual energy yields for all three technologies decrease with increasing order of AM bands. The performance ratio for HIT and m-SI modules initially increases and then decreases with increasing order of AM bands. However, for a-Si modules, the performance ratio decreases with increasing order of the AM bands. 相似文献
69.
Parise Henry Olufunmilayo Owopetu Demilade Adisa Thao Nguyen Kevin Anthony David Ijoni-Animadu 《Journal of environmental science and health. Part. B》2016,51(8):546-552
The free living nematode Caenorhabditis elegans is a proven model organism for lipid metabolism research. Total lipids of C. elegans were extracted using chloroform and methanol in 2:1 ratio (v/v). Fatty acids composition of the extracted total lipids was converted to their corresponding fatty acids methyl esters (FAMEs) and analyzed by gas chromatography/accurate mass quadrupole time of flight mass spectrometry using both electron ionization and chemical ionization techniques. Twenty-eight fatty acids consisting of 12 to 22 carbon atoms were identified, 65% of them were unsaturated. Fatty acids containing 12 to17 carbons were mostly saturated with stearic acid (18:0) as the major constituent. Several branched-chain fatty acids were identified. Methyl-14-methylhexadecanoate (iso- 17:0) was the major identified branched fatty acid. This is the first report to detect the intact molecular parent ions of the identified fatty acids in C. elegans using chemical ionization compared to electron ionization which produced fragmentations of the FAMEs. 相似文献
70.
近年来,长三角地区灰霾天气持续增多,空气细颗粒物污染问题日益突出。基于2013年1月至2015年5月长三角地区及周边缓冲区内共214个空气质量监测站点PM2.5逐时监测数据,运用普通克里金插值方法,从年、季、月尺度上分析了PM2.5的空间分布格局和时间动态变化。结果表明:(1)2 a来,长三角地区PM2.5浓度空间分布明显呈现整体北部高南部低,局部地区略有突出的分布特征;长三角地区PM2.5浓度年均值为57.08μg/m3;其中,江苏省PM2.5的年均值为三省市最高,为65.84μg/m3;其次为上海市,年均值为53.87μg/m3;浙江省PM2.5的年均值较小,为51.53μg/m3。(2)从季节尺度分析,长三角地区PM2.5浓度变化表现出冬春季高,夏秋季低的变化趋势;这与区域内冬季风向来源、降水稀少、气象扩散条件差有着密切的关系; (3)长三角地区月浓度变化大致呈U形分布; 12月份PM2.5浓度最高; 3月份以后, PM2.5浓度开始呈逐步下降趋势;在5~9月份,区域PM2.5处于"U"字的谷底,其中6月份夏收时期秸秆焚烧、气象等因素导致PM2.5浓度有略微升高;进入10月份后迅速攀升,且11、12月份呈现持续升高态势。 相似文献