广州街道空气中挥发烃类特征和来源分析

采用固相吸附－热脱附－色谱／质谱检测器联用的方法分析了广州市街道空气中的发挥有机物。样品采自广州市区街道的３２个采样点,主要探讨了其中单环芳烃和正构烷烃的特征和可能来源;选取１３种烃类化合物进行进一步的因子分析,结果表明,这些挥发烃类可能主要来自汽油机车、工业和柴油机车的排放。多元线性回归分析表明３种源对所选挥发烃类的平均贡献分别为６４％、２３％和１３％。     

粤港澳地区大气中有机污染物初步研究

用Ｔｅｋｍａｒ多填层吸附管连接ＴＭＰ－１５００空气采样采集ＶＯＣｓ样,然后在Ｔｅｋｍａｒ６０３２／３０００吹扫捕集系统与ＧＣ／ＭＳＤ联用仪上分析,用ＴＨ－１０００Ｌ型大量采样器收集ＴＳＰ气溶胶样,ＴＳＰ滤膜经抽提分离后,烷径和芳烃进行ＧＣ／ＭＳＤ分析,了广州,香港和澳门地区大气 有机物和气溶胶可溶有机物的与成因。     

Concentrations of Heavy Metals in Hair and Nails of Young Pakistanis: Correlation with Dietary Elements

Hair and nail samples from young Pakistani adults were separately analyzed for quantification of Cd, Cr, Cu, Ni, Pb, and Zn concentrations. The concentrations of these metals were also analyzed in commonly consumed local foods to evaluate potential correlation of hair and nail concentrations with diet. Pearson correlation coefficients ranged from 0.349 to 0.999, demonstrating diet to be a significant contributor for accumulation of heavy metals in humans.     

纳米TiO2对幼年小鼠血浆代谢谱影响的代谢组学研究

观察不同染毒剂量的纳米TiO2对ICR幼年小鼠血浆代谢谱变化的影响,寻找潜在的毒性效应的生物标志物.将幼年小鼠随机分为对照组以及10、30、100和300 mg·kg-1不同纳米TiO2染毒组进行28 d短期毒性试验,利用代谢组学技术初步筛选出TiO2毒性作用潜在的生物标志物,运用KEGG数据库对生物标志物进行拓扑分析...     

Accumulation of radionuclides released to a reactor discharge pond

Due to material degradation in tubing, the heat exchanger for the primary coolant of the 1 MW Tsing Hua Open-pool Reactor has minor leakage to the secondary cooling system since 1970. In the past 20 years, trace amounts of ^58,60Co, ⁵¹Cr, ¹³⁷Cs, ⁵⁴Mn, ⁴⁶Sc, and ⁶⁵Zn have leaked through the cooling system, accumulated, and eventually trapped in the discharge pond directly in front of the reactor. The distribution of these radionuclides in the mud at different depths and various locations in the pond was measured with standard procedures of radioactive soil sampling and counting techniques. Concentration of corrosion products, with no more than 40 KBq/Kg dry at the hottest spot, was contour-mapped to reveal the accumulation patterns of these trace level radioactive products at the end of the 20-year period.     

菜谱里的饮食观

年夜饭可称得上是一个风向标，某种意义上它是一个人或一个家庭对这一年来生活水平认同的标志。虽然如此说法难免偏颇，但它却叮能是年夜饭的普泛性特征——这一年收入好，年夜饭层次就上去了；反之，这一年生活不景气，则年夜饭难免表现气短。     

北京大气PM2.5中微量元素的浓度变化特征与来源

为了解北京大气细粒子中微量元素的污染水平和来源,在车公庄和清华园进行了连续1年、每周1次的PM2.5采样和全样品分析.微量元素浓度的周变化大,尤以冬季为甚,相邻2周最大相差达1.6倍;但除冬季的平均浓度较高之外,其季节变化并不显著.微量元素的富集因子在春季最低,反映了频繁发生的沙尘天气的影响.Se、Br和Pb的浓度比来自于北京A层土壤中的含量要高出约1000～8000倍,表明它们主要来自于人为污染.其中Se的富集度最高,反映了北京细粒子来自于燃煤污染的特征.Pb的年均浓度(0.31μg@m-3)虽然未超过WHO的年均标准,但与洛杉矶和布里斯班相比处于较高的水平;与Br、Se的比较分析表明,燃煤可能是Pb除机动车排放之外的另一个重要来源.     

回归自然之美

掩映在青山绿水之中的莲花山庄酒店，葱茏别致。除了环境的优美，酒店所提供的五星级服务让您的会务、商务之旅多了几分自然的情怀和绿色的遐想。推开窗子就是远山近水，在幽静高雅的饮食环境中，品尝中西合璧的美食，用享受的心态去过一种纯粹的酒店生活。     

农药降解质粒向根瘤菌的转移

研究了细菌农药降解质粒P~(JP4)向根瘤菌的转移以及农药降解质粒引入根瘤菌后,对其共生性、固氮能力和根瘤结构的影响。结果表明,三种根瘤菌受体均接受了农药2,4-D降解质粒P~(JP4)。转移频率在4.0×10~(-6)—6.4×10~(-6)之间。其中一个受体菌株在灭菌土壤中接受该质粒,其转移频率为5.1×10~(-7)。接受了农药降解质粒的接合子保持了根瘤菌的共生性状、乙炔还原活性,所形成的根瘤结构与亲本株没有明显差别。从根瘤中分离的接合子仍保持了质粒P~(JP4)。     

Human exposure to respirable suspended particulate and airborne lead in different roadside microenvironments

The aim of this study is to evaluate the particulate air pollution in selected roadside microenvironments of Hong Kong through an intensive field study dated from January 1997 to February 1997. The study employed the microenvironment monitoring technique to access the exposure of pedestrians to respirable suspended particulate and airborne lead (Pb) at heavily trafficked roadsides. A total of 62 roadside sites in 14 districts covering the most urbanized and densely populated areas were selected. It was found that pedestrians were exposed to a 24 h average of respirable suspended particulate, PM10, and airborne Pb (APb), typically ranged from 25.56 to 337.40 microg/m3 and 70.71 to 285.71 ng/m3, respectively. The average PM10 concentrations at different roadside microenvironments corresponding to urban residential, urban commercial, urban industrial and new town areas were 91.84, 129.08, 83.83, and 118.89 microg/m3 respectively. The corresponding values for APb were 130.01, 143.40, 127.40 and 173.17 ng/m3, respectively. It was found that measurement at EPD nearby rooftop monitoring stations might not reflect the actual roadside PM10 exposure. Most APb field study data was significantly higher than the nearby fixed station data.