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11.
A thermophoretic precipitator (TP) that uses a novelty of direct sampling of ambient air particulate matter (PM) onto transmission electron microscopy (TEM) grids was designed and utilized to determine its potential applicability for the collection and consequent qualitative analyses of representative PM in the air, especially those with aerodynamic diameter less than 1 microm (PM1.0). After a calibration process, preliminary field tests were performed under different weather conditions, locations, and time frames. TEM, selected area electron diffraction (SAED), and electron energy-dispersive X-ray spectrometry (EDS) analyses were performed on individual samples, and chemical species were analyzed. During this investigation, individual air PM with different sizes ranging from 10 microm to 10 nm for TEM analysis was collected. Two observations were made: (1) a large fraction of collected particulates were aggregates of very small particles of both organic and inorganic origin, and (2) a large fraction of the collected particulates were crystalline or polycrystalline. This study has demonstrated, by utilization of SAED patterns from TEM on air particles collected by a TP, the potential to analyze and identify individual air PM in a nanometer regime qualitatively by combining SAED and EDS data.  相似文献   
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宜兴市清源污水处理厂升级改造工艺设计   总被引:1,自引:0,他引:1  
宜兴市清源污水处理厂升级改造工程设计规模5×104m3/d,采用强化生物脱氮、机械微过滤(盘片过滤)工艺,利用现有池容进行内部改造,同时增加深度处理设施,提高出水标准,改造后出水ρ(COD)、ρ(BOD5)、ρ(SS)、ρ(NH3-N)、ρ(TN)和ρ(TP)平均值分别为34,6,5,1.3,10.3和0.36mg/L,各项水质指标均达GB18918-2002《城镇污水处理厂污染物排放标准》一级A标准。  相似文献   
14.
Laboratory and field filtration experiments were conducted to study the effectiveness of As(V) removal for five types of adsorbent media. The media included activated alumina (AA), modified activated alumina (MAA), granular ferric hydroxide (GFH), granular ferric oxide (GFO), and granular titanium dioxide (TiO2). In laboratory batch and column experiments, the synthetic challenge water was used to evaluate the effectiveness for five adsorbents. The results of the batch experiments showed that the As(V) adsorption decreased as follows at pH 6.5: TiO2 > GFO > GFH > MAA > AA. At pH 8.5, however, As(V) removal decreased in the following order: GFO = TiO2 > GFH > MAA > AA. In column experiments, at pH 6.5, the adsorbed As(V) for adsorbents followed the order: TiO2 > GFO > GFH, whereas at pH 8.5 the order became: GFO = TiO2 > GFH when the challenge water containing 50 μg/L of As(V) was used. Field filtration experiments were carried out in parallel at a wellhead in New Jersey. Before the effluent arsenic concentration increased to 10 μg/L, approximately 58,000 and 41,500 bed volumes of groundwater containing an average of 47 μg/L of As(V) were treated by the filter system packed with GFO and TiO2, respectively. The As(V) adsorption decreased in the following sequence: GFO > TiO2 > GFH > MAA > AA. Filtration results demonstrated that GFO and TiO2 adsorbents could be used as media in small community filtration systems for As(V) removal.  相似文献   
15.
We present a new methodology for database-driven ecosystem model generation and apply the methodology to the world's 66 currently defined Large Marine Ecosystems. The method relies on a large number of spatial and temporal databases, including FishBase, SeaLifeBase, as well as several other databases developed notably as part of the Sea Around Us project. The models are formulated using the freely available Ecopath with Ecosim (EwE) modeling approach and software. We tune the models by fitting to available time series data, but recognize that the models represent only a first-generation of database-driven ecosystem models. We use the models to obtain a first estimate of fish biomass in the world's LMEs. The biggest hurdles at present to further model development and validation are insufficient time series trend information, and data on spatial fishing effort.  相似文献   
16.
沿海农田林网建设关键技术的经济学择优   总被引:2,自引:0,他引:2  
对江苏沿海地区农田林网的经营类型、造林树种、林带配置进行了技术经济学分析和多目标灰色局势决策择优。结果表明:农田林网经营类型宜选择复合经营的果材兼用型林网。造林树种可选择速生丰产的杨树等用材树种和经济效益高的桃树等果树。林网配置在海堤河岸上选择用材树种,营造基干林带,筑起大网格框架;在道路沟渠上立体配置林果树种,营造主林带和副林带,构建中网格;在脱盐排水沟上添加果树辅助林带,建立小网格,形成多树种多林种合作、大中小网格配套、多道防线联防、多效益多产品产出的复合配置模式。  相似文献   
17.
Intrauterine treatment of 4 fetuses with urethral obstruction was attempted in the third trimester of pregnancy. The fetuses displayed varying sonographic findings including pyelectasis, caliectasis, hydroureter, bladder dilatation, ascites, hydrops, missing kidneys and oligohydramnios. Ultrasonically guided aspiration from the dilated structures was carried out to relieve pressure on the kidney parenchyme and to collect fluid samples for diagnostic purposes. Amino acid concentrations in the fetal urine showed a pattern similar to plasma in 2 fetuses, a pattern almost like urine in 1 fetus and an intermediate pattern in the 4th fetus. Only the fetus with normal amino acid concentrations in the urine survived: the other 3 died in uremia shortly after birth. In 3 cases cells from the aspirated urine were cultured and used for chromosome analysis. The cell cultures grew fast and karyotyping was possible within 1 week. In 2 fetuses an intrauterine catheter was inserted to drain the kidney permanently into the amniotic cavity. In the first case the catheter was displaced to the fetal abdomen after some days of successful drainage. In the second case the catheter tore the placenta, and the child had to be delivered immediately.  相似文献   
18.
大直径薄壁钢筒变薄旋压成形工艺研究   总被引:2,自引:0,他引:2  
论述大径比高精钢筒变薄旋压成形试验过程 ,通过确定合理工艺过程 ,选择最佳工艺参数 ,从而旋出了合格筒体。结果表明 ,D40 6A钢退火状态变薄旋压性能良好 ,旋压塑性变形稳定 ;有效控制扩径量和壁厚差是变薄旋压成形和获取高精钢筒的关键  相似文献   
19.
We report three cases of Turner's syndrome with cystic hygromata, which were diagnosed by routine ultrasound scanning before amniocentesis in the second trimester of pregnancy. Maternal and amniotic level of alpha-fetoprotein were normal. Karyotyping carried out afterwards showed a 45,X karyotype. Our data indicate, that cystic hygromata in Turner's syndrome may coexist with a normal amniotic fluid AFP, thus questioning the theory of leakage from the hygroma. It remains to be investigated if all cases of Turner's syndrome present a cystic hygroma in utero.  相似文献   
20.
In copper based antifouling (AF) paints Cu (I) oxide was largely used as booster biocide. In this study effect of Cu (I) oxide on two marine microalgae, Tetraselmis suecica and Dunaliella tertiolecta was demonstrated. EC50 (96 hr) concentrations estimated for T. suecica and D. tertiolecta were 1.3 mg l(-1) and 1.34 mg l(-1), respectively. Copper (I) oxide induced changes in growth, chlorophyll, carbohydrate and protein contents were observed in T. suecica and D. tertiolecta. At low concentration of 0.0625 mg l(-1), 3-26% and 1-16% growth stimulation was observed in T. suecica and T. tertiolecta respectively. Increasing Cu (I) oxide concentrations proportionately decreased the carbohydrate and protein contents. This study clearly indicates the toxicity of excessive Cu (I) oxide on growth and biochemical compositions of T. suecica and D. tertiolecta.  相似文献   
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