重庆玉峡锶矿床中分散元素锶的超常富集机制   总被引：2，自引：0，他引：2  

朱创业 《矿物岩石地球化学通报》1998,(4)

重庆玉峡锶矿床位于华蓥山构造带的南段。含矿岩系为下三叠统嘉陵江组二段一亚段的含藻含膏白云岩,含矿层位自下而上有三个矿层。矿层呈似层状、透镜状赋存于西山背斜北段的背斜转折端及相邻两翼的层间虚脱部位。矿石矿物有天青石、菱锶矿、钡天青石,脉石矿物为白云石、...  相似文献   

环境污染及保护对策     

刘大任 《江西地质》1998,12(3):195-200

环境保护中一个非常重要的工作,是广泛深入地开展环境地质工作。在赣南、江西乃至全国,环境地质工作的主要内容是防治水土流失,严禁废渣、废水随意排放,控制人口激增,保护有限耕地;为保护生态平衡,必须加强环境立法与执法,提高环境保护的重要性和必要性的认识,大规模切实地保护耕地,因地制宜植树造林。  相似文献   

贵金属资源的应用及开发   总被引：1，自引：1，他引：0  

唐杰  张凯 《世界地质》1998,17(4):98-102

将贵金属的应用,资源分布,生产和贵金属的分析化学结合在一起进行了综述,由于贵金属资源的短缺性及考虑可持续发展战略,特别介绍了贵金属资源的二次回收问题,并对其将来的发展作了一定的评价和展望。  相似文献   

Scaling the Vertical Structure of Sea Breezes     

D.G. Steyn 《Boundary-Layer Meteorology》1998,86(3):505-524

This analysis presents a new set of scalings for sea-breeze circulations. The scales are based on surface-layer turbulent fluxes of sensible heat and momentum, thus avoiding the use of exchange coefficients. Nondimensionalization of the governing equations, using the new scales, results in four dimensionless governing parameters, two of which are new. A data set consisting of 36 profiles of atmospheric variables during pure sea-breeze circulations is presented. The data are used to generate scaling laws for dimensionless sea-breeze depth and strength in the form of products of powers of the governing dimensionless parameters. These scaling laws are used to nondimensionalize individual velocity profiles, which are composited to present a universal dimensionless sea-breeze velocity profile. The scaling laws, applied as a diagnostic scheme, are used to investigate the diurnal evolution of the depth and strength of sea breezes.  相似文献   

大豆蛋白废水处理中泡沫分离过程的数学模型     

杨向平  刘元东  席作家  翟绪丽 《中国海洋大学学报(自然科学版)》2008,38(1):111-115

假设吸附过程始终处于平衡态、气泡大小均一以及每一个气泡均为正十二面体,构建了泡沫分离过程的数学模型.模拟了液池中蛋白质在气液界面上的吸附过程和泡沫层中气泡的失水过程,得出了富集比的表达式,可用于分离效果的预测.经验证,模型与实验条件下的泡沫分离过程基本符合.  相似文献   

加拿大海盆北部营养盐限制作用研究   总被引：1，自引：1，他引：0  

李宏亮  陈建芳  高生泉  卢勇  金海燕  白有成  庄燕培  张海生 《海洋学报》2015,37(11):147-154

利用2008年夏季中国第三次北极科学考察获得的营养盐、叶绿素a、温度和盐度等数据资料,结合现场营养盐添加实验的结果讨论西北冰洋加拿大海盆北部营养盐对浮游植物生长的限制作用。结果表明:由于融冰水稀释作用,加拿大海盆B80站约20m深度存在较强的盐跃层,阻碍了水体上下混合。较低浓度的溶解无机氮(DIN)和硅酸盐(分别为0.31μmol/L和0.94μmol/L)以及严重偏离Redfield比值的N/P、N/Si比值(分别为0.42和0.32)表明加拿大海盆表层水体存在N和Si限制。根据现场营养盐加富实验各培养组叶绿素a浓度变化、营养盐吸收总量差异和浮游植物种群结构,进一步表明氮是北冰洋海盆首要限制营养盐,而Si则抑制了硅质生物的生长。同时,较小的硝酸盐半饱和常数(Ks)证明即使在营养盐充足的情况下北冰洋海盆浮游植物生长速率也处于较低水平。计算得到各培养组营养盐吸收比例(N/P比值)均大于Redfield比值,可能是培养实验过程中以微型、微微型浮游植物为主,硅藻等小型浮游植物为辅造成的。  相似文献   

Observed winds,turbulence, and dispersion in built-up downtown areas of Oklahoma City and Manhattan   总被引：2，自引：2，他引：0  

Steven Hanna  John White  Ying Zhou 《Boundary-Layer Meteorology》2007,125(3):441-468

Wind and tracer data from the Oklahoma City Joint Urban 2003 (JU2003) and the Manhattan Madison Square Garden 2005 (MSG05) urban field experiments are being analyzed to aid in understanding air flow and dispersion near street-level in built-up downtown areas. The mean winds are separately calculated for groups of anemometers having similar exposures such as “near street level” and “on building top”. Several general results are found, such as the scalar wind speed at street level is about 1/3 of that at building top. Turbulent standard deviations of wind speed components and temperature, and vertical fluxes of momentum and sensible heat, are calculated from sonic anemometers near street level at 20 locations in JU2003 and five locations in MSG05, and from two rooftop locations in MSG05. The turbulence observations are consistent with observations in the literature at other cities, although the JU2003 and MSG05 data are unique in that many data are available near street level. For example, it is found that the local (i.e., at the measuring height) averages about 1.5 and the local averages about 0.25 in the two cities, where is the standard deviation of vertical velocity fluctuations, is the friction velocity, and u is the wind speed. The ratio of temperature fluctuations to temperature scale, , averages about −3 in both cities, consistent with similarity theory for slightly unstable conditions, where is the standard deviation of temperature fluctuations, and is the temperature scale. The calculated Obukhov length, L, is also consistent with slightly unstable conditions near street level, even at night during JU2003. The SF₆ tracer concentration observations from JU2003 are analyzed. Values of for the continuous releases are calculated for each release and arc distance, where is the 30-min average arc maximum concentration, Q is the continuous source emission rate, and u is the spatial-averaged wind speed in the downtown area. The basic characteristics of the JU2003 plot of averaged agree reasonably well with similar plots for other urban experiments in Salt Lake City and London (i.e., at . A is found to be about 3 during the day and about 10 during the night.  相似文献   

Occurrence and fate of polycyclic aromatic hydrocarbons in the coastal surface microlayer   总被引：2，自引：0，他引：2  

Guitart C  García-Flor N  Bayona JM  Albaigés J 《Marine pollution bulletin》2007,54(2):186-194

Polycyclic aromatic hydrocarbons (PAHs) were measured in the coastal sea surface microlayer (SML), the sub-surface waters (SSW) and the overlying atmosphere in order to investigate the influence of the SML on contaminant enrichment and air-sea exchange. Samples were collected at two contrasting locations of the NW Mediterranean, one urban influenced (off Barcelona, Spain) and another comparatively clean (off Banyuls-sur-Mer, France). Statistical data analysis confirmed the accumulation of PAHs in the SML with respect to the SSW (20.3+/-9.1 vs. 13.1+/-10.0 ng L(-1) in the dissolved phase; 709+/-207 vs. 158+/-111 ng g(-1) in the particulate phase). This accumulation was higher at the contaminated location (Barcelona station) compared with the more pristine one, with PAH enrichments 1.5 and 4.5 times higher for the dissolved and particulate phases, respectively, indicating that the enrichment of PAHs in the SML is dominated by particle transport processes.  相似文献   

The use of meiofauna as an indicator of benthic organic enrichment associated with salmonid aquaculture   总被引：4，自引：1，他引：3  

Sutherland TF  Levings CD  Petersen SA  Poon P  Piercey B 《Marine pollution bulletin》2007,54(8):1249-1261

Sediment chemistry and meiofaunal samples were collected in the Broughton Archipelago, British Columbia, to examine the relationship between sediment variables and meiofauna diversity across near- and far-field gradients surrounding several finfish aquaculture operations. The sediment variables examined consisted of free sulfide concentrations, redox potential (E(NHE)), organic content, and sediment grain size. A strong trend between sediment texture and organic content was observed across all sampling locations, which reflected a wide range of sediment types (sand-silt) that exist within the Broughton Archipelago. The abundance of certain meiofaunal groups (kinorhynchs, crustaceans, polychaetes) declined in an asymptotic fashion with increasing free sulfide concentrations, an indicator of benthic organic enrichment. Within these relationships, low meiofaunal abundances occurred in fine sediments associated with higher organic contents. Although other groups (nematodes, foraminifera) showed a slight decline in abundance with increasing organic enrichment, a high amount of variability in abundance was observed at high free sulfide concentrations, rendering these groups not suitable as indicators of organic enrichment. This study reports both horizontal and vertical trends in meiofaunal distributions relative to free sulfide concentrations. The abundance of nematode and crustacean taxa decreased with sediment depth as well as increasing sulfide concentration, while polycheate abundance increased with increasing free sulfide concentration. The ratio of nematodes to copepods was also shown to represent the degree of organic loading associated with aquaculture operations and its application as an indicator of benthic impact is discussed.  相似文献   

福建沿海地区表层土壤铅来源及分布特征     

刘顺民 《福建地质》2010,29(3):238-243

在福建省沿海经济带生态地球化学调查的基础上,应用富集因子法对福建省沿海地区表层土壤中铅的来源进行了分析,并对其自然来源和人为来源的分布特征及影响因素做了初步探讨。结果表明,福建沿海地区约98.2%的土地面积表层土壤中铅属于自然来源,其余地区含有人为来源铅,且集中分布于个别市县城区;铅自然来源区呈现广域性分布特征,人为来源区则呈现零星的斑点状分布特点;铅自然来源区和人为来源区的空间分布特征在很大程度上受到土壤类型、森林植被分布以及人为活动等因素的影响。  相似文献