Spatial variation in nitrogen dioxide in three European areas

In order to estimate the spatial variation within well-defined study areas, nitrogen dioxide was measured with diffusion samplers (Palmes tube) in 40-42 sites each in Germany (Munich), the Netherlands and Sweden (Stockholm County). Each site was measured over four 2-week periods during 1 year (spring 1999 to summer 2000). In each country, one reference site was measured during all periods and the results were used to adjust for seasonal variability, to improve the estimates of the annual average. Comparisons between the chemiluminescence method (European reference method) and Palmes tube measurement indicated a good agreement in Germany (with a ratio of 1.0 for Palmes tube/chemiluminescence) but underestimation for Palmes tube measurement in the Netherlands and Sweden (0.8 for both countries). The r2 values were between 0.86 and 0.90 for all three countries. The annual average values for NO2 for different sampling sites were between 15.9 and 50.6 (mean 28.8 microg/m3) in Germany, between 12.1 and 50.8 (mean 28.9 microg/m3) in the Netherlands and between 6.1 and 44.7 (mean 18.5 microg/m3) in Sweden. Comparing spatial variation between similar sites in the three countries, we did not find any significant differences between annual average levels for urban traffic sites. In Sweden, annual average levels in urban background and suburban backgrounds sites were about 8 microg/m3 lower than comparable sites in Germany and the Netherlands. Comparing site types within each country only urban traffic sites and suburban background sites differed in Germany. In the Netherlands and Sweden, the urban traffic sites differed from all other sites and in Sweden also the urban background sites differed from the other background sites. The observed contribution from local traffic was similar in the Netherlands and Sweden (10 and 8 microg/m3, corresponding to 26-27% of the NO2 concentration found in the urban traffic sites). In Germany, the contribution from local traffic was only 3 microg/m3, corresponding to 9% of the NO2 concentration found in the urban traffic sites. The spatial variation was substantially larger for NO2 than the variation for PM2.5 and similar to PM2.5 absorbance, measured in the same locations.     

美国西部电气公司洁净室的一些做法

洁净室根据其工作区内气流的控制方式分成乱流型和层流型两种。也可以根据实际操作中能够维持的洁净度分类。洁净室要求采用与洁净度相适应的设备、材料、房屋清扫程序以及工作人员操作方法。不论其气流设计型式或洁净度等级如何,洁净室一般都由图1所示各部分组成。循环风机使主要送风进入和通过洁净室、初过滤器和末级过滤器。空气处理装置供给所需要的冷量和热量。补风系统的风机为洁净室加压,并补充     

Spatial patterns of cadmium and lead deposition on and adjacent to National Park Service lands in the vicinity of Red Dog Mine, Alaska

Heavy metal escapement associated with ore trucks is known to occur along the DeLong Mountain Regional Transportation System (DMTS) haul road corridor in Cape Krusenstern National Monument, northwest Alaska. Heavy metal concentrations in Hylocomium splendens moss (n = 226) were used in geostatistical models to predict the extent and pattern of atmospheric deposition of Cd and Pb on Monument lands. A stratified grid-based sample design was used with more intensive sampling near mine-related activity areas. Spatial predictions were used to produce maps of concentration patterns, and to estimate the total area in 10 moss concentration categories. Heavy metal levels in moss were highest immediately adjacent to the DMTS haul road (Cd > 24 mg/kg dw; Pb > 900 mg/kg dw). Spatial regression analyses indicated that heavy metal deposition decreased with the log of distance from the DMTS haul road and the DMTS port site. Analysis of subsurface soil suggested that observed patterns of heavy metal deposition reflected in moss were not attributable to subsurface lithology at the sample points. Further, moss Pb concentrations throughout the northern half of the study area were high relative to concentrations previously reported from other Arctic Alaska sites. Collectively, these findings indicate the presence of mine-related heavy metal deposition throughout the northern portion of Cape Krusenstern National Monument. Geospatial analyses suggest that the Pb depositional area extends 25 km north of the haul road to the Kisimilot/Iyikrok hills, and possibly beyond. More study is needed to determine whether higher moss heavy metal concentrations in the northernmost portion of the study area reflect deposition from mining-related activities, weathering from mineralized Pb/Zn outcrops in the broader region, or a combination of the two. South of the DMTS haul road, airborne deposition appears to be constrained by the Tahinichok Mountains. Heavy metal levels continue to diminish south of the mountains, reaching a minimum in the southernmost portion of the study area near the Igichuk Hills (45 km from the haul road). The influence of the mine site was not studied.     

高温透明铝电解槽中50cm2石墨阳极上气泡析出行为

铝电解阳极气泡行为对研究电解质流场模拟和阳极效应都至关重要.本文采用高温透明电解槽观测了底面积为50 cm2(10 cm×5 cm)的石墨阳极上的气泡行为,实验温度为924℃.结果表明:在阳极电流密度为0.3～1.7A/cm2范围内,最大气体覆盖率在48％～65％之间,与工业电解槽炭阳极上的最大气体覆盖率相近,低于文献...     

Highly Aligned Ultra-Thick Gel-Based Cathodes Unlocking Ultra-High Energy Density Batteries

Increasing electrode thickness can substantially enhance the specific energy of lithium-ion batteries;however,ionic transport,electronic conductivity,and ink rheology are current barriers to adoption.Here,a novel approach using a mixed xanthan gum and locust bean gum binder to construct ultrathick electrodes is proposed to address above issues.After combining aqueous binder with single-walled carbon nanotubes(SWCNT),active material(LiNi_0.8Co_0.1Mn_0.1O₂)...     

CRISPR基因编辑作物有望走上消费者的餐桌（英文）OA

<正>In the not-too-distant future,it looks increasingly likely that grocery stores will offer food genetically altered in myriad slight ways to make it healthier,tastier,and more efficient to grow.In 2022,a flurry of research results and regulatory changes around the world brought gene-edited crops closer to consumers’plates.     

Waweon测试仪——动态测试和分析股线与经纱张力

描述了安装有股线及经纱传感器的Waweon测试仪及其测试和评估方法.例举了来自织机和缝纫机的相关图表.独特的测试和评估软件方便了仪器操作,挖掘了应用潜力.Waweon独特的设计理念使该机不仅可以应用在工业上,也可用于产品开发以及职业技术学校,大大扩展了应用领域.     

可提高生产效率的新型张力控制装置

对剑杆织机的引纬系统来说,张力控制装置起着非常重要的作用。如今,在许多场合,尤其是在织造低强或弱捻纱时,张力控制装置（如Iro／Poj生产的TEC装置）,都已经标准化。TEC的功能很好,但为了向其他领域迈进,在以下几个方面还应加以改善：     

Feedback Control of Plasma Current and Horizontal Position in HT-7 Tokamak

There is a strong magnetic coupling between poloidal field coils of superconductive tokamak HT-7, These coils are connected to individual power     

Preliminary Results from the TCABR Tokamak

After a long period of assembling and repairing faulty components, tokamak discharges started this year to be routinely obtained in TCABR. TCABR was brought from Lausanne-Switzerland some years ago. It is a middle size ohmic