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31.
于1997年11—12月(枯水期)、1998年8月和10月(丰水期),对长江从金沙江至河口干流和主要支流、湖泊入江口各种形式的无机氮进行调查。结果表明,长江枯、丰期,干、支流NO3—N平均浓度变化很小,NO2—N、NH4—N浓度枯水期显著高于丰水期,支流高于干流;长江NO3—N、NH4—N和DIN在枯、丰期具有基本相似的迁移过程;长江水中无机N的迁移变化主要取决于NO3—N,NO3—N始终是三态无机N的主要存在形式,三态无机N处于较稳定的热力学平衡状态中;长江干流无机N与径流量呈正相关表明长江水中无机N主要来自于面源。 相似文献
32.
黄河水中无机固体粒子与4种重金属液-固界面的交换作用 总被引:2,自引:0,他引:2
于 1 996年 5— 1 2月在实验室用离子交换法对黄河干流内蒙古清水河县喇嘛湾断面黄河水中无机固体粒子与Cu2 、Pb2 、Zn2 、Cd2 的液 -固界面作用进行了研究 ,得出离子交换率E %与pH的关系 ,找出了 4种重金属离子的pH突跃范围和最大离子交换率。结果表明 ,在黄河水中 4种重金属离子主要以羟基络合物的形式M(OH) 与无机固体粒子进行一价阳离子交换。随金属离子浓度增加E %降低 ,4种重金属离子与转型沙的交换率大于未转型沙。 相似文献
33.
V. A. Kudryavtsev N. J. C. Spooner P. K. Lightfoot J. W. Roberts M. J. Lehner T. Gamble M. J. Carson T. B. Lawson R. Lüscher J. E. McMillan B. Morgan S. M. Paling M. Robinson D. R. Tovey N. J. T. Smith P. F. Smith G. J. Alner S. P. Hart J. D. Lewin R. M. Preece T. J. Sumner W. G. Jones J. J. Quenby B. Ahmed A. Bewick D. Davidge J. V. Dawson A. S. Howard I. Ivaniouchenkov M. K. Joshi V. Lebedenko I. Liubarsky J. C. Barton G. Gerbier J. Mallet L. Mosca C. Tao 《Astroparticle Physics》2002,17(4):79-408
The status of dark matter searches with inorganic scintillator detectors at Boulby mine is reviewed and the results of tests with a CsI(Tl) crystal are presented. The objectives of the latter experiment were to study anomalous fast events previously observed and to identify ways to remove this background. Clear indications were found that these events were due to surface contamination of crystals by alphas, probably from radon decay. A new array of unencapsulated NaI(Tl) crystals immersed either in liquid paraffin or pure nitrogen atmosphere is under construction at Boulby. Such an approach allows complete control of the surface of the crystals and the ability to remove any surface contamination. First data from the unencapsulated NaI(Tl) do not show the presence of anomalous fast events. 相似文献
34.
Mineral particles could have influenced on the climate of Oviedo, a non-industrial city situated in the centre of an industrial
zone of the North of Spain, increasing the temperature and the precipitations, in spite of the fact that “greenhouse gases”
concentrations have diminished in this city in recent years. The directive (1999/30/EC) of the European Commission began to
be applied in Oviedo in the year 2003. In agreement with this norm, our first aim was the identification of the inorganic
particulate matter of the PM10 and PM2.5 fractions sampled in this city. X-ray diffraction and scanning electron microscopy
coupled with X-ray dispersive energy spectrometry were used. The percentages of the different mineral phases of the PM were
obtained by a Rietveld refinement of powder X-ray diffraction data. The compositions of the PM10 and PM2.5 fractions of this
city are similar. Sulphates are the most abundant particles in the both fractions. Most sulphates, nitrates and sal-ammoniac
would have formed by reaction between solid, liquid and/or gas particles and they could be associated with the power stations
near to the city and traffic. Wüstite and haematites come from the iron and steel industries of Gijón and Avilés. The main
natural sources of halite and carbonates and silicates are sea spray and soil resuspension by the wind, respectively. 相似文献
35.
Free floating subsea robots are often subjected to complex hydrodynamic loads due to waves/currents and wakes from nearby structures. This makes control extremely difficult. Good hydrodynamics data might counteract this. This paper presents hydrodynamics data for two configurations undergoing various combinations of steady translation and approximately steady rotation. The two configurations are: a spherical body with a single fixed link arm and a two link arm without a body. For both configurations neural networks were found to provide a reasonable fit to the data. We believe that such fits could be used to improve control. 相似文献
36.
37.
根据 1998年的现场调查资料 ,分析考洲洋海水无机营养盐与浮游植物生物量的平面分布及其相互关系。结果表明二者的关系很密切 :浮游植物量在枯水期 (2月 )与无机氮、无机磷、硅酸盐显著正相关 ,相关系数分别为 0 779、0 94 6和 0 876 (n =12 ) ;在丰水期 (8月 )与无机氮和硅酸盐负相关、与磷酸盐正相关 ,相关系数分别为 - 0 6 5 5、- 0 84 5和 0 5 84 (n =11)。从浮游植物对营养盐的一般需要量和N、P、Si的原子比分析 ,2月N、P显得紧缺 ,8月N、P、Si均过量 相似文献
38.
39.
ISORROPIA: A New Thermodynamic Equilibrium Model for Multiphase Multicomponent Inorganic Aerosols 总被引:16,自引:0,他引:16
A computationally efficient and rigorous thermodynamic model that predicts the physical state and composition of inorganic atmospheric aerosol is presented. One of the main features of the model is the implementation of mutual deliquescence of multicomponent salt particles, which lowers the deliquescence point of the aerosol phase.The model is used to examine the behavior of four types of tropospheric aerosol (marine, urban, remote continental and non-urban continental), and the results are compared with the predictions of two other models currently in use. The results of all three models were generally in good agreement. Differences were found primarily in the mutual deliquescence humidity regions, where the new model predicted the existence of water, and the other two did not. Differences in the behavior (speciation and water absorbing properties) between the aerosol types are pointed out. The new model also needed considerably less CPU time, and always shows stability and robust convergence. 相似文献
40.