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991.
洗洁精在金及其伴生元素光度分析中的应用 总被引:2,自引:0,他引:2
详细研究了在洗洁精存在下,金以有银,铜,锌,汞,铊等元素与金试剂,硫代米酮,5-Br-PADAP显色体系的光度性质。结果表明,市售洗洁精是一种物美价廉,性能良好的增溶,增敏,增稳试剂,在光度分析中具有广阔的应用前景。 相似文献
992.
993.
对在加油站的防雷设计中,出现的一些问题进行分析归类,指出了设计不规范的地方和原因,在加油站的防雷设计、审核和检测中应加以注意。 相似文献
994.
Suzi M. Ribeiro Elianne P. Omena Guilherme Muricy 《Estuarine, Coastal and Shelf Science》2003,57(5-6):951-959
The macrofauna (endo- and epi-biotic) associated to the sponge Mycale (Carmia) microsigmatosa Arndt, 1927 was studied at three sites in Rio de Janeiro State, Brazil (Arraial do Cabo, Niterói, and Rio de Janeiro). A total of 2235 individuals (over 1 mm long) of 75 invertebrate species were found associated to 19 specimens of the sponge. The most abundant and diverse taxa were the crustaceans (83%, 31 spp.), polychetes (10%, 18 spp.), and molluscs (3.7%, 15 spp.). Cnidarians, platyhelminthes, ascidians, echinoderms, pycnogonids, bryozoans, and sponges were also represented. Amphipod crustaceans were the dominant group, comprising 61% of all individuals collected. Species richness and abundance of associated fauna were highly correlated with sponge volume, but diversity and evenness were not. The site of collection influenced the species composition of the fauna associated to M. microsigmatosa but did not change significantly its diversity, abundance, richness, and dominance patterns of higher taxa. Pregnant females and juvenile stages of 29% of the species associated, including crustaceans, molluscs, echinoderms, and pycnogonids were frequently found inside M. microsigmatosa. Although many of these organisms do occur and reproduce in other habitats outside the sponge as well, M. microsigmatosa is also important for their reproduction and survivorship, thus contributing for the maintenance of biodiversity in Southwestern Atlantic sublittoral rocky shores. 相似文献
995.
Lightning activity and precipitation structure of hailstorms 总被引:1,自引:0,他引:1
FENG GuiLi QIE XiuShu YUAN Tie & NIU ShuZhen Laboratory of Lightning Thunderstorm Cold Arid Regions Environmental Engineering Research Institute Chinese Academy of Sciences Lanzhou China Shandong Research Institute of Meteorology Jinan China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China The Meteorological Observatory of Henan Province Zhengzhou China 《中国科学D辑(英文版)》2007,50(4):629-639
By using the cloud-to-ground (CG) lightning location data from the lightning detection network of He- nan Province, surface Doppler radar data and standard orbit data of PR, TMI and LIS on TRMM satellite, the spatial and temporal characteristics of CG lightning flashes in 10 severe hailstorms are analyzed. The results show that the percentage of CG lightning in these hailstorms is high with an average value of 45.5%. There is a distinct increase in CG flash rate during the rapid development stage of hailstorms. The hailstone falling corresponds to an active positive flash period, and the increase of CG flash rate is generally accompanied with a decrease of –CG flash rate. The flash rate declines rapidly during the dissipating stage of hailstorms. The precipitation structure and lightning activity in two typical hail- storms are studied in detail. It is found that strong convective cells with reflectivity greater than 30dBZ mainly are situated in the front region of hailstorms, whereas the trailing stratiform region is in the rear part of the hailstorms. The maximum heights of echo top are higher than 14 km. Convective rain con- tributes much more rainfall to the total than stratiform rain, and the convective rain takes about 85% and 97% of the total in the two cases, respectively. Total lightning in the hailstorms is very active with the flash rate up to 183 fl/min and 55 fl/min, respectively. The results also indicate that most lightning flashes occurred in the echo region greater than 30 dBZ and its immediate periphery. The probability of lightning occurrence is 20 times higher in the convective region than in the stratiform region. The result suggests that the lightning information is helpful to the identification of convective rain region. The linear relationship between flash rate and ice water content is disclosed primarily. 相似文献
996.
997.
完善建筑物内部防雷装置设计的实践经验 总被引:2,自引:0,他引:2
根据进一步完善建筑物内部防雷装置设计一些实践经验,提出了新建建筑物应从分流、屏蔽、接地和等电位连接等方面综合来考虑,使其达到综合防雷目的。 相似文献
998.
成都地区地闪时空特征分析 总被引:3,自引:0,他引:3
利用XDD03A型闪电定位仪所取得的3年资料,初步研究了成都周边地区地闪特征。地闪中正地闪占绝大多数,其平均强度为6045 A,略高于负地闪的5974 A。地闪强度基本集中在12000 A以下。地闪活动具有明显的日变化,总体呈单峰单谷形式,地闪频次在60以上的峰值时段是18:00~24:00和01:00,频次在10以下的谷值时段是10:00~13:00,夜间闪电活动明显大于日间。正地闪频次日变化趋势和总地闪相同,负地闪频次日变化趋势除一些小波动外,和正地闪、总地闪相同。正负地闪频次的月变化趋势相同,6、7、8月闪电数较多,4、5、9、10月闪电数较少。通过统计分析,发现各月地闪频次和对应的各月降水量有较好的相关性。成都周边地区地闪活动密集,6、7、8月的地闪密度大大超过4、5、9、10月。 相似文献
999.
Spatiotemporal characteristics of positive cloud-to-ground lightning discharges and bidirectional leader of the lightning 总被引:4,自引:0,他引:4
Krehbiel Paul 《中国科学D辑(英文版)》2006,49(2):212-224
The negative CG lightning discharges neutralizing negative charges in cloud usually dominate for most of thunderstorms. However, a lot of positive CG light-ning discharges often occur in the disappearing stage of thunderstorms, in the stratiform region of mesoscale convective systems and some supercells producing hail and tornado. Because the positive CG lightning discharges produce larger current of the return stroke and neutralize more charges due to the continuing currents with longer las… 相似文献
1000.
通过对南宁市新建建筑物防雷设计文件审核的总结,依据相关防雷设计规范,提出对新建建筑物进行防雷设计审核时应注意的几个方面。 相似文献