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31.
解决山东水资源短缺的对策 总被引:1,自引:0,他引:1
分析了山东省水资源现状和存在的主要问题,针对山东省水资源的严重短缺,提出了在传统用水、治水的基础上,实施人工增雨工程,直接利用海水和海水淡化与节约用水,建立节水型社会,调整水源结构,更新用水观念,开发新水源,综合用水,综合治水的路子,只有这样才能长久解决水危机。 相似文献
32.
利用气象观测资料、NCEP/NCAR 1°×1°再分析资料以及GDAS资料,对2021年10月2-7日山西持续性强降水天气过程进行分析。结果表明:稳定的乌拉尔山低槽后部冷空气扩散,中纬度短波槽东移,与副热带高压外围西南暖湿气流持续交汇,同时高低空急流耦合形成强烈上升运动,低层切变线和地面辐合线稳定维持,及低层水汽不断输送并形成辐合,为持续性强降水的发生发展提供有利动力和水汽条件。此次强降水过程分为对流性降水和稳定性降水2个阶段,2阶段水汽输送通道的源地、路径、高度均有明显差异,但水汽输送贡献率均以对流层中低层山西南侧的水汽输送占主导地位。降水开始前,对流层中上层存在对称不稳定,大气可降水量明显跃增;对流性降水阶段,干空气不断入侵,对流不稳定快速建立与释放,对流层中低层水汽辐合区与强上升气流配合,导致山西出现强对流天气。地形的阻挡、抬升及地形收缩作用,对局地极端强降水具有增幅作用。 相似文献
33.
在氧化沉淀法去除铁的过程中,氧化反应分别在自然曝气、充气和除钙的条件下进行,对照结果进行分析,得出最佳的除铁配方,同时还着重对氧化反应速率及其影响因素(pH,Eh等)进行了探索性研究,为以后试验提供了一定的依据。 相似文献
34.
35.
Miwako Nakaseama Jun-Ichiro Ishibashi Keita Ogawa Hiroshi Hamasaki Keiko Fujino Toshiro Yamanaka 《Resource Geology》2008,58(3):289-300
The Wakamiko submarine crater is a small depression located in Kagoshima Bay, southwest Japan. Marine shallow‐water hydrothermal activity associated with fumarolic gas emissions at the crater sea floor (water depth 200 m) is considered to be related with magmatic activity of the Aira Caldera. During the NT05‐13 dive expedition conducted in August 2005 using remotely operated vehicle Hyper‐Dolphine (Japan Agency for Marine‐Earth Science and Technology), an active shimmering site was discovered (tentatively named the North site) at approximately 1 km from the previously known site (tentatively named the South site). Surface sediment (up to 30 cm) was cored from six localities including these active sites, and the alteration minerals and pore fluid chemistry were studied. The pore fluids of these sites showed a drastic change in chemical profile from that of seawater, even at 30 cm below the surface, which is attributed to mixing of the ascending hydrothermal component and seawater. The hydrothermal component of the North site is estimated to be derived from a hydrothermal aquifer at 230°C based on the hydrothermal end‐member composition. Occurrence of illite/smectite interstratified minerals in the North site sediment is attributed to in situ fluid–sediment interaction at a temperature around 150°C, which is in accordance with the pore fluid chemistry. In contrast, montmorillonite was identified as the dominant alteration mineral in the South site sediment. Together with the significant low potassium concentration of the hydrothermal end‐member, the abundant occurrence of low‐temperature alteration mineral suggests that the hydrothermal aquifer in the South site is not as high as 200°C. Moreover, the montmorillonite is likely to be unstable with the present pore fluid chemistry at the measured temperature (117°C). This disagreement implies unstable hydrothermal activity at the South site, in contrast to the equilibrium between the pore fluid and alteration minerals in the North site sediment. This difference may reflect the thermal and/or hydrological structure of the Wakamiko Crater hydrothermal system. 相似文献
36.
Studies of Mesozoic granites associated with rare earth element (REE)‐rich weathered crust deposits in southernmost Jiangxi Province indicate that they have high‐K to shoshonite compositions and belong to ilmenite‐series I‐type granites. Of the studied rocks at 59–292 ppm of bulk REE content, the highest are seen in the biotite granites of Dingnan (358, 429 ppm) and mafic biotite granite of the Wuliting Granite (344 ppm) near the Dajishan tungsten mine, both areas where weathered‐crust REE deposits occur. REE‐bearing accessory minerals in these granites are mainly zircon, apatite and allanite, and REE‐fluorocarbonates are common. REE enrichment occurs in the rims of apatite crystals, and in fluorocarbonates that occur along grain boundaries of and cracks in major silicate minerals, and in fluorocarbonates that replaced altered biotite. It is therefore thought that a major part of the REE content of these granites was concentrated during deuteric activity, rather than during magmatic crystallization. The crack‐filling REE‐fluorocarbonates could subsequently have been easily leached out and deposited in weathered crust developed during a long period of exposure. 相似文献
37.
对塔中低凸起地层水化学特征与不整合之间关系的研究结果表明,地层水化学特征对不整合具有很好的响应。在遭受强烈抬升和剥蚀、之间形成不整合的奥陶系和志留系,以及紧靠不整合面附近的石炭系CⅢ油组,其地层水具有矿化度、Cl-含量、K Na 含量和r(Cl-Na)/rMg值相对较小,而HCO3-含量、rNa/rCl值和rSO42-×100/rCl值相对较大的特点,反映出地质历史时期大气降水的影响。在志留系与石炭系之间以及志留系与奥陶系之间的不整合面附近,地层水的矿化度、r(Cl-Na)/rMg值和B3 含量变小,而rNa/rCl值和rSO24-×100/rCl值变大,具有典型的遭受大气淋滤的地层水化学基本特征。 相似文献
38.
Water and sediment samples collected from the Gomti River, a tributary of the Ganges River system, during the postmonsoon season have been analyzed to estimate major elemental chemistry. Water chemistry of the River Gomti shows almost monotonous spatial distribution of various chemical species, especially because of uniform presence of alluvium Dun gravels throughout the basin. The river annually transports 0.34×106 tonnes of total suspended material (TSM) and 3.0×106 tonnes of total dissolved solids (TDS), 69 percent of which is accounted for by bicarbonate ions only. Samples collected downstream of the city of Lucknow show the influence of anthropogenic loadings for a considerable distance in the river water. Na+, Cl–, and SO4
2– concentrations build up downstream. The bed sediment chemistry is dominated by Si (36 percent), reflecting a high percentage of detrital quartz, which makes up about 74 percent of the mineralogy of the bed sediments in the River Gomti. The average Kjeldahl nitrogen concentration (234 g/g) indicates indirectly the amount of organic matter in the sediments. The Hg concentration in sediments has been found to be higher (average 904 ppb) than the background value. The suspended sediments are well sorted, very finely skewed, and extremely leptokurtic, indicating a low energy condition of flow in the Gomti River. The influence of chemical loads in the Gomti has been found to be small or nonexistent on the Ganges River, perhaps because the water discharge of the Gomti (1.57 percent) to the Ganges is quite low. 相似文献
39.
The kinetics of the aqueous phase reactions of NO3 radicals with HCOOH/HCOO– and CH3COOH/CH3COO– have been investigated using a laser photolysis/long-path laser absorption technique. NO3 was produced via excimer laser photolysis of peroxodisulfate anions (S2O
8
2–
) at 351 nm followed by the reactions of sulfate radicals (SO
4
–
) with excess nitrate. The time-resolved detection of NO3 was achieved by long-path laser absorption at 632.8 nm. For the reactions of NO3 with formic acid (1) and formate (2) rate coefficients ofk
1=(3.3±1.0)×105 l mol–1 s–1 andk
2=(5.0±0.4)×107 l mol–1 s–1 were found atT=298 K andI=0.19 mol/l. The following Arrhenius expressions were derived:k
1(T)=(3.4±0.3)×1010 exp[–(3400±600)/T] l mol–1 s–1 andk
2(T)=(8.2±0.8)×1010 exp[–(2200±700)/T] l mol–1 s–1. The rate coefficients for the reactions of NO3 with acetic acid (3) and acetate (4) atT=298 K andI=0.19 mol/l were determined as:k
3=(1.3±0.3)×104 l mol–1 s–1 andk
4=(2.3±0.4)×106 l mol–1 s–1. The temperature dependences for these reactions are described by:k
3(T)=(4.9±0.5)×109 exp[–(3800±700)/T] l mol–1 s–1 andk
4(T)=(1.0±0.2)×1012 exp[–(3800±1200)/T] l mol–1 s–1. The differences in reactivity of the anions HCOO– and CH3COO– compared to their corresponding acids HCOOH and CH3COOH are explained by the higher reactivity of NO3 in charge transfer processes compared to H atom abstraction. From a comparison of NO3 reactions with various droplets constituents it is concluded that the reaction of NO3 with HCOO– may present a dominant loss reaction of NO3 in atmospheric droplets. 相似文献
40.