北京东南郊大气TSP中多环芳烃浓度特征与影响因素

对2005-03～2006-01北京市东南郊3个采样点大气总悬浮颗粒物（TSP）样品进行分析,总结了研究区内TSP以及TSP中16种PAHs的浓度特征和季节变化规律.研究区内16种PAHs浓度总和的范围在0.29～1?184.48 ng/m³之间,均值为239.44 ng/m³;分别用气象参数（温度、风速、气压、相对湿度）和大气API指数（二氧化硫、二氧化氮、PM₁₀）与PAHs浓度进行了偏相关分析,结果表明温度和SO₂的API指数与PAHs浓度相关显著,应用逐步回归方法得到PAHs对气象参数和大气API指数的回归方程,分别为∑16PAHs=572.56-23.18t和∑16PAHs=5.99 SO₂,可以利用温度和SO₂的API指数对PAHs浓度进行估算.     

微生物絮凝剂的现状与前景分析

综述了传统絮凝剂在水处理中存在的缺陷以及微生物絮凝剂在水处理中的优越性，对微生物絮凝剂可能在将来取代或部分取代传统的无机及有机高分子絮凝剂作了科学的分析，并针对现今微生物絮凝剂发展的不足指出了今后的发展趋势。     

焦化废水处理中酚、氰降解细菌的分离选育

针对焦化废水为含酚、氰废水的特性，从焦化厂处理焦化废水的活性污泥和油泥中分离出能降解酚的细菌7株，降解氰的细菌8株，并对其降解能力进行了测定，结果表明，当酚浓度为150mg/L，经6h处理后0512菌株对酚的去除率达96．84％，当CN^-浓度为25mg/L经8h处理后，0501菌株对CN^-的去除率达99．96％。     

不同植被下土壤碳转移对岩溶动力系统中碳循环的影响

土壤是陆地生物生长、发育、繁殖的最佳场所,也是岩溶发育最为活跃的部位。土壤～岩石(土箱)、草本植物(麦冬)-土壤-岩石(草箱)、木本植物(黄杨)-土壤-岩石(树箱)体系中碳循环的模拟试验显示,黄杨具有较大的树冠可截获更多的降雨,根系的呼吸作用、分泌作用和土壤微生物活力的提高,使土壤环境中CO2浓度提高,树箱比土箱、草箱分别提高148.08%、75.01%,而土壤呼吸排放CO2的量则分别提高175.75%、171.14%;随水排泄的无机碳浓度分别提高77.78%、72.49%,排泄的总量分别提高166.49%、153.81%。碳循环强度的增加,使土下碳酸盐岩的侵蚀能力加强,树箱比土箱提高2.84倍、比草箱提高1.36倍。     

至2050年中国生态高值农业体系建设特征与目标

2010年6月7日,国家主席胡锦涛在两院（中国科学院、中国工程院）院士大会上针对农业科技明确指出：构建我国生态高值农业和生物产业体系,建成农业高值转化的产业体系。本文对＂生态高值农业＂进行论述。所谓生态,就是要体现农业既能为社会提供安全优质的农产品又能实现农业资源的永续利用,将农业纳入可持续发展的道路;所谓高值,就是要体现农业有很高的土地产出率、投入产出率、劳动生产率。因此,＂生态高值农业＂是集约化经营与生态化生产有机结合的现代农业。它以健康消费需求为导向,以提高农业市场竞争力和可持续发展能力为核心,兼有高投入、高产出、高效益与可持续发展的双重特性,是转变农业增长方式、提高农业综合生产能力的集中体现。     

First-trimester maternal serum human chorionic gonadotrophin as a marker for fetal chromosomal disorders

The Dutch Working Party on Prenatal Diagnosis has initiated a study on the possibilities of first-trimester screening for fetal chromosomal disorders. We report on maternal serum human chorionic gonadotrophin (MS-hCG) measurements in 1348 pregnancies with a chromosomally normal fetus and 53 pregnancies with a chromosomally abnormal fetus. The median MS-hCG concentration in 24 pregnancies with Down's syndrome was 1.19 multiples of the normal median (MoM). The MS-hCG distributions in normal and Down's syndrome pregnancies did not differ significantly (t-test: t = 1.945, p >0.05). We also found no difference between normal pregnancies and pregnancies with other chromosomal disorders (six cases of trisomy 18, MoM = 0.80; four cases of sex chromosome abnormality, MoM = 1.01; 17 cases of chromosomal mosaicism in chorionic villi, MoM = 1.11). Selecting an upper limit at the 90th centile could detect 25 per cent of pregnancies with Down's syndrome. We conclude that, in the first trimester, MS-hCG as a screening factor for Down's syndrome is of minor value. However, MS-hCG could be a useful factor in a first-trimester screening programme based on a combination of markers.     

不锈钢导管挤压扩口工艺与模具设计

介绍了飞机不锈钢导管原位挤压扩口工艺和模具设计.该模具具有结构简单、易于加工、更换方便等特点,该工艺不仅适用于飞机导管修理,而且还可供其它设备导管修理时参考.     

Maternal serum CA 125 levels in pregnancies with chromosomally-normal and -abnormal fetuses

We measured the maternal serum cancer antigen 125 (MS-CA 125) levels in 98 nonpregnant women, 765 first- and second-trimester pregnancies with chromosomally-normal fetuses, and 54 chromosomally-abnormal pregnancies. To determine the MS-CA 125 concentration, we used a new automated microparticle enzyme immunoassay with low inter-assay variability. The median MS-CA 125 level decreased from the first to the second trimester of pregnancy and was higher than that in non-pregnant women. We found no difference between normal and Down's syndrome (n = 29) pregnancies ( t-test: t = 0·57, p >0·5). The MS-CA 125 levels in pregnancies with other chromosomal abnormalities showed no difference either, compared with the normals. We conclude that MS-CA 125 is not a useful marker for fetal Down's syndrome, nor for other chromosomal disorders in pregnancy.