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781.
782.
783.
A chemical module describing the tropospheric photochemistry of ozone precursors in both gaseous and aqueous phases for a remote continental atmosphere has been developed within the framework of a two-dimensional cloud model. Dynamical, microphysical and chemical processes are fully interacting in order to study the influence of clouds on ozone chemistry and to quantify the relative importance of the different processes on the budget and evolution of 12 chemical species. Whereas the concentrations of highly soluble species are strongly affected by evaporation and sedimentation, less soluble species are affected primarily by accretion. The model reproduces previously observed chemical phenomena such as the enrichment of formic acid at the top of the cloud. 相似文献
784.
W. Wobrock D. Schell R. Maser W. Jaeschke H. -W. Georgii W. Wieprecht B. G. Arends J. J. Mols G. P. A. Kos S. Fuzzi M. C. Facchini G. Orsi A. Berner I. Solly C. Kruisz I. B. Svenningsson A. Wiedensohler H. -C. Hansson J. A. Ogren K. J. Noone A. Hallberg S. Pahl T. Schneider P. Winkler W. Winiwarter R. N. Colvile T. W. Choularton A. I. Flossmann S. Borrmann 《Journal of Atmospheric Chemistry》1994,19(1-2):3-35
785.
变质流体的溶液化学 总被引:2,自引:0,他引:2
Brucew.D.Yardley 《地学前缘》1994,(Z1)
变质流体中载有重要的溶解物质,这些溶解物不但在交代作用过程中起着重要作用,而且还影响着固相平衡。岩石中的某些组分(如氧化硅),虽溶于水但却不能形成络合物,即便在有附加配位体的情况下也是如此。大多数阳离子的浓度主要取决于络合配位体的有效性。尽管氯化物是配位体中最重要的成员,但对某些金属而言,那些较次要的配位体却更为有效。 相似文献
786.
东台吉乃尔盐湖卤水的相化学研究(Ⅰ):25℃等温蒸发实验 总被引:1,自引:4,他引:1
为了研究东台吉乃尔盐湖卤水蒸发时的相化学,确定钾盐、镁盐和锂盐的结晶路线和结晶特性,在实验室内对卤水进行了25℃等温蒸发结晶过程的研究.实验结果与Na+、K+、Mg(2+)//Cl-、SO—H2O五元水盐体系介稳相图进行了比较与讨论. 相似文献
787.
A novel cryogenic sampling method combining the matrix isolation technique with FTIR spectroscopy has been developed for atmospheric trace gas analysis. It is applicable to a wide range of molecules with detection limits typically in the 10–50 ppt range. The method is described along with some measurements of N2O, CFCl3, CF2Cl2, OCS, CS2, SO2 and PAN from samples collected at ground level and from an aircraft between 9 and 14 km. 相似文献
788.
Wet deposition due to radiation fog is examined in this paper. The area where the reported measurements were performed, the Po Valley, northern Italy, is characterized by both a high fog occurrence during the fall-winter months and fog water solutions of high ionic concentration and acidity.Estimated wet deposition for NH
4
+
, NO
inf3
sup-
and SO
inf4
sup2-
ions due to fog droplet settling to the ground accounts for 13.2, 12.1 and 5.3 percent with respect to bulk precipitations over the same period: January–March and October–December (fog season).Fog deposition rates show that this process can be an important pathway of trace gases and particles loss from the air. First indicative results of fog removal efficiency with respect to air particulate matter are presented.Dry deposition parameters should be taken into account in evaluating the potential effect of fog droplet deposition on vegetation. 相似文献
789.
Single-cycle and multiple-cycle frictional-sliding experiments were employed to evaluate the effects of pore fluid environments on yield strength, frictional-sliding dynamics, and gouge production and morphology. Circular right cylinders cored from Berea sandstone sawcut at 35° to the axes were saturated in water, an inorganic brine, and various anionic, cationic, and nonionic aqueous surface-active agents. Samples were deformed under an effective confining pressure of 50 MPa and an axial strain rate of 6×10–5 sec–1 until a 2% axial strain beyond yield (defined as the onset of sliding) was achieved. All samples were displaced by stable sliding. In the single-cycle tests the unsaturated and water-saturated samples displayed small stress peaks at yield. During stable sliding samples saturated with DTAB and SDS displayed slight increases in differential stress and statistically significant higher frictional coefficients than other environments (including water) but were very similar in behavior to dry, unsaturated samples. In the multiple-cycle tests, samples were loaded to 2% strain beyond yield and unloaded to a differential stress of approximately 5–10 MPa a total of four times. These results further suggest that DTAB exerts a strengthening effect on the sandstone relative to water which, to a limiting value, increased with displacement. The DTAB and SDS environments also produced a coarser grain-size distribution in the gouge relative to gouge produced in the other environments. Investigation of the gouge by scanning electron microscope revealed that these larger grains were composed of dense, apparently cemented aggregates of ultrafine, platy quartz particles. 相似文献
790.
M. Renard N. Chaumerliac S. Cautenet N. Audiffren E. C. Nickerson 《Journal of Atmospheric Chemistry》1995,20(3):237-258
The sensitivity of the horizontal and vertical transport of an inert tracer to seasonal variability of the complex West Africa circulations is explored by means of a 2D mesoscale meteorological model including explicit microphysics and describing the cloud dynamics of these circulations. The seasonal variations of the location and spatial extent of the cloudy masses associated with the Inter Tropical Convergence Zone (ITCZ) are reproduced in a meridional cross section over West Africa. The redistribution of the inert tracer is shown to be due to the northward migration of the ITCZ from January to July and also to the enhancement of the convective activity of the ITCZ in July. The redistribution of carbon monoxide during the dry and wet seasons is discussed, highlighting the importance of the biomass burning during the dry season as a source of trace gas enrichment in the upper levels of the tropical troposphere over West Africa. 相似文献