以DDTC为螯合剂反相HPLC法分离测定铜钴镍汞

本文研究了用ODS柱对DDTC与Cu、Co、Ni、Hg四种重金属离子螯合物的分离测定方法。经过对流动相及其配比、波长、柱温、压力、流速等色谱条件进行的选择,对共存离子影响的分析,确定了最佳分离分析条件。以58:42(v:y)的乙醇水溶液作流动相在R.P.柱上分离,于254nm处检测。在0.0064～1.Oμg/ml(Cu),0.0064～1.0μg/ml(Co),0.0032～1.0μg/ml(Ni),0.010～1.0μg/ml(Hg)浓度范围内,线性关系良好。对含量在线性范围内的天然水样和人尿样进行了分析测定,回收率在97.0～109.0％之间,变异系数不超过5.6％,结果较好。     

The short term response to eutrophication abatement

We compare results of a new model for predicting the short term inter annual changes in chlorophyll-a (chl-a) in lakes after reductions in total phosphorus (TP) to predictions made by least squares regression models. In the new method, slopes of chl-a/TP graphs (both axes in mg · m^–3) are depicted in frequency diagrams and used to extract information on the expected, short term chl-a/TP response. The short term response for nine shallow (< 10 m deep) and nutrient rich lakes to changes in TP was found to be: Chl-a = 0.49 · TP + 17.3, and for nine deep, P-limited lakes: Chl-a = 0.08 · TP + 3.5. If the TP-reduction is known to be greater than 10 mg · m^–3, the expected slope increases to 0.58 for shallow lakes and to 0.26 for deep lakes. The slope, 0.58, is 8% lower than the slope for the long term response calculated by regression for the shallow lakes. For deep lakes the slope, 0.26, is 2 to 3 times higher than that calculated by regression, indicating that reductions in TP for deep lakes give greater effects than least squares regression equations suggest. We have also calculated the reduction in TP which will give about 80% probability that a reduction in chl-a will be observed next year. For shallow, P-limited lakes this reduction is about 30 mg · m^–3 (5% of average initial in-lake TP concentration), and for deep lakes about 14 mg · m^–3 (35% of average initial in-lake TP concentration).     

Vertical mixing in Überlinger See,western part of Lake Constance

Depth variable vertical eddy diffusion coefficients for heat (K _z) were calculated from continuously measured temperature profiles in Überlinger See (western part of Lake Constance). The temperatures were averaged over vertical intervals of 10 m yielding 14 discrete values (maximum depth of Überlinger See: 147 m). A linear fit from 10 June to 29 September 1987 was used to smooth the significant temperature fluctuations caused by internal seiches of Lake Constance.Assuming horizontal homogeneity for the smoothed data the Gradient-Flux-Method was applied to compute vertical diffusion coefficientsK _z at different depths using the depth variable volumes and surfaces of the 14 layers. The resulting mean diffusion coefficients for the period from June to September are 0.04 cm²/s near the thermocline and up to 0.8 cm²/s in deeper strata (accuracy: ± 50%). It is shown that horizontal mixing between Überlinger See and Obersee (main lake) alters the computation ofK _z by less than 50%.A relationship betweenK _z and stability (Brunt-Väisälä) frequencyN is found which corresponds well to the theory of internal wave induced turbulence.Combining the diffusion coefficients with measured phosphorus profiles, a phosphorus flux from the hypolimnion to the epilimnion of (0.7 ± 0.4) mg P m^–2 d^–1 was calculated, corresponding to about 20% of the average external loading per area of Lake Constance in 1986.     

永和磷矿氧化带银星石的矿物学特征

银星石产于永和磷矿氧化带中。该矿床面型氧化带深度5－30m，线型氧化带深度250m。在氧化带中，除碳氟磷灰石外，银星石是较常见的产物，与银星石伴生的表生磷矿还有纤磷钙铝石和磷锶铝矾等。本文研究了银星矿物的地质产状、物理化学性质，以及银星石赖于发育的氧化带地质特征，同时指出了研究银星石和磷矿氧化带对表生矿物学、磷矿床找矿勘探均有实际意义。     

攀枝花层状侵入体韵律层理及岩浆演化特征

通过详细研究并综合前人工作，本文着重对攀枝花岩体微型韵律层理的特征和成因作了详细论述；并对岩浆演化方式作了进一步探讨；同时对富钛铁氧化物熔浆的熔离作用进行了深入的阐述。     

Vegetation and soil characteristics of the wasteland of Valika Chemical Industries near Manghopir, Karachi

The vegetation of the wasteland of Valika chemical industries near Manghopir road, Karachi was studied. Nine plant communities were recognized based on dominant species. In these plant communities the vegetation was disturbed, mostly halophytic and dominated bySuaeda fruticosa,Tamarix indica,Salsola baryosma,Cressa cretica,Atriplex griffithii,Haloxylon recurvum,Indigofera hochstetteri,Prosopis julifloraandChenopodium album.The physico-chemical properties of the soils were also analysed. Soil texture was mostly sandy loam, which exhibited slight variations in the water-holding capacity. The soils contained a sufficient amount of CaCO₃⁻and exhibited mostly alkaline soil pH. The soils of the different plant communities had scarcely any organic matter or inorganic phosphorus. The exchangeable sodium in the soils of many halophytic plant communities was high, with appreciable concentrations of potassium.     

Seasonal dynamics of a cyanobacteria-dominated microbial community in surface sediments of a shallow,eutrophic lake

The seasonal variation of microbial biomass and activity in the surface sediments (0–10 cm) of the shallow, eutrophic Lake Vallentunasjön was followed during one year. OverwinteringMicrocystis colonies dominated the microbial community during all seasons, constituting 60–90% of the total microbial biomass. Expressed on an areal basis, the benthic biomass was, throughout the year, larger than or similar to the planktonic biomass during the peak of the summer bloom, indicating an ability of the colonies to survive in the sediments for extended periods. Abundance of other, non-photosynthetic bacteria varied in the range 3.0–15.5 · 10¹⁰ cells g^–1 d. w. over the year with minimum values in summer and maximum values in autumn in connection with the sedimentation of theMicrocystis bloom. A substantial part of the non-photosynthetic bacteria, up to circa 40%, was associated with the mucilage of healthyMicrocystis colonies. Bacterial production (³H-thymidine incorporation) appeared to be strongly temperature dependent and less influenced by the seasonal sedimentation pattern. Our data indicate an increasing proportion of non-growing cells in autumn and winter. Biomass-bound phosphorus constituted a significant portion, circa 10%, of the phosphorus content in Lake Vallentunasjön sediments. This pool has normally been overlooked in studies on phosphorus dynamics in lake sediments. Different mechanisms whereby organic phosphorus can be released from the sediments are discussed.     

Block Kriging for Lognormal Spatial Processes

Lognormal spatial data are common in mining and soil-science applications. Modeling the underlying spatial process as normal on the log scale is sensible; point kriging allows the whole region of interest to be mapped. However, mining and precision agriculture is carried out selectively and is based on block averages of the process on the original scale. Finding spatial predictions of the blocks assuming a lognormal spatial process has a long history in geostatistics. In this article, we make the case that a particular method for block prediction, overlooked in past times of low computing power, deserves to be reconsidered. In fact, for known mean, it is optimal. We also consider the predictor based on the “law” of permanence of lognormality. Mean squared prediction errors of both are derived and compared both theoretically and via simulation; the predictor based on the permanence-of-lognormality assumption is seen to be less efficient. Our methodology is applied to block kriging of phosphorus to guide precision-agriculture treatment of soil on Broom's Barn Farm, UK.     

From Micro to Meso: an exercise in determining hydraulic conductivity of fractured sandstone cores from detailed characterization of the fractures

Hydraulic conductivities of fractured sandstone bore cores of 0.1 m in diameter are calculated using detailed characterization of the fracture geometry parameters determined using a resin casting technique. The accuracy of the measurements was about  0.25–1.25 μm  with the image size used. The values of the effective fracture apertures vary between 10 μm and 50 μm. For modelling purposes the samples are sectioned serially, perpendicular to the flow direction along the cylinder axis. The hydraulic conductivity of individual slices is estimated by summing the contribution of the matrix (assumed uniform) and each fracture (depending on its length and aperture). Finally, the hydraulic conductivity of the bulk sample is estimated by a harmonic average in series along the flow path. Results of this geometrical upscaling compare favourably with actual conductivity measured in hydraulic and pneumatic experiments carried out prior to sectioning. This study shows that the determination of larger-scale conductivity can be achieved, based on the evaluation of fracture geometry parameters (e.g. fracture aperture, fracture width and fracture length), measured using an optical method, at least at the laboratory scale.     

陕西潼关金矿区泥石流潜势度评价

陕西潼关金矿区位于小秦岭北坡，区内发生的泥石流灾害，其物源90％是采矿弃渣。本文选择采矿弃渣量、纵坡降比、渣堆补给长度与沟长比、沟岸山坡坡度、河流弯曲程度、河流堵塞情况、渣堆稳定性、流域面积、历史上有无泥石流灾害发生等9个泥石流发生的因子，在给定因子权重排序的基础上，采用因子权值与因子赋值相乘后相加的方法，求得18条沟谷泥石流潜势度指数及其排序。在降雨量相同的条件下，潜势度指数可似比风险度指数。