冀西北水晶屯金矿床剥蚀程度的判别方法

从冀西北水晶屯金矿近矿围岩蚀变的空间组合、金的指示元素的空间特征、黄铁矿标型特征等多方面地质数据资料入手，来判别矿床的剥蚀程度，认为该金矿床剥蚀程度正处在矿体的中上部。     

恢复生态学及其发展

简述了国内外恢复生态学的发展概况，分析了我国在生态系统退化的原因、生态学过程以及退化生态系统恢复重建的方法和生态学机理等方面的研究进展。针对我国在恢复生态学研究和退化生态系统恢复实践中存在的问题，提出了加强我国恢复生态学研究的建议。     

混合式球面退化剖分模型的设计与编码

为了解决球面退化四叉树格网(DQG)模型孔径较大、格网单元面积分布不均匀以及三角格网单元应用不完全四叉树剖分的问题,通过控制单元面积的思路设计了一种格网单元孔径更小、分布更均匀的四边形(中低纬地区)与三角形(高纬地区)的混合格网模型——混合式球面退化格网模型(MSDG);并对所有格网单元利用四叉树进行编码.通过对格网单元的几何属性统计分析发现,该格网模型的几何属性与DQG模型相比,其单元面积变化更小、分布更加均匀稳定.     

Satellite based long-term assessment of rangeland condition in semi-arid areas: An example from Botswana

A methodology was devised for comparison of generalised range condition over time, irrespective of the nature of original imagery used. It was applied for range condition change mapping throughout Botswana through 1984-2000. Results showed that range degradation was most widespread during the 1980s drought when 25% of the country was affected, decreased to 6.5% in 1994 and increased to 9.8% in 2000. This suggests that these semi-arid rangelands are fairly resilient and can withstand “normal” droughts even under conditions of heavy grazing pressure. However, degradation that persists during normal or above average rainfall years is related to increasing livestock and other pressures on rangelands and may represent areas with severe range recovery problems. This application meets some requirements of a semi-arid developing country looking to improve range condition monitoring over relatively remote areas.     

Index test for the degradation potential of carbonate sands during hydraulic transportation

Carbonate sands undergo degradation when transported hydraulically from a dredging vessel to the reclamation site. Risks involved in the production of fines during hydraulic transport are a deterioration of the mechanical properties of the fill in certain areas of the reclamation area where these fines concentrate. In order to assess sand degradation in the concrete and road construction industry, the Micro-Deval test for fine aggregates was developed in France and Canada. During Micro-Deval testing, aggregates degrade when tumbled in a rotating steel drum with water and steel balls. In the Canadian standard, the steel charge is lower than in the French standard and balls have the diameter of the smallest balls used in the French test. During testing, the quantity of fines produced is measured. This makes the Micro-Deval test an option for assessing the degradation of sand during hydraulic transportation of slurries in the dredging industry. Three sands are tested: two shelly carbonate sands and one quartzic river sand for comparison. The carbonate sands were sampled on reclaimed land and had been subjected to hydraulic transportation in pipeline before artificial deposition. Due to differences in particle shape, the carbonate sands and the quartz sand have a different number of contacts with the steel charge in the drum of the Micro-Deval and are not exposed to the same degradation forces during testing. It was found that the quartzic sand suffers relatively much degradation as compared to the carbonate sands, despite its greater hardness and resistance to crushability. The French test appears to create turbulence that promotes floatation of the curved shells of the carbonate sands instead of shell grinding at the bottom of the drum by contact with the steel balls. Microscopic observations of sand samples before and after testing showed that the French Micro-Deval test is too destructive. The test leads to the fragmentation by impact of the quartz sands and the destruction of certain particle types that had survived hydraulic transportation. With respect to the Canadian test, microscopic examination of sand grains before and after testing shows there is still much fragmentation of quartz grains. A lower rotational speed combined with a limited steel charge made of uniform balls of a smaller diameter, reduces turbulence, shell floatability and last but not the least, impact forces. It produces the desired result: a high Micro-Deval loss for the carbonate sands in comparison to that for the quartz sands and a very limited fragmentation of the quartz grains. Once the slurry reaches its destination, the grain size distribution of the fines fraction will influence the mechanical behaviour of mixed sands. A procedure is proposed to measure the particle size distribution of the fines fraction produced during Micro-Deval testing.Field validation is needed to validate preliminary laboratory results.     

A mechanistic study on the photodegradation of Irgarol-1051 in natural seawater

The kinetics of the photoinduced degradation and transformation of the antifouling booster biocide, Irgarol-1051, in natural coastal seawater was studied. The measured first-order rate constant for the degradation of Irgarol-1051 was 4.02 ± 0.1 × 10⁻⁴ h⁻¹, while the rate constant for the formation of 2-methylthio-4-tert-butylamino-6-amino-s-triazine (M1), the most dominant degradation product of Irgarol-1051, was 4.6 ± 0.1 × 10⁻⁵ h⁻¹. This considerably slower rate suggested that the transformation of Irgarol-1051 to M1 may not be the predominant pathway of the photodegradation process. During the photodegradation study, a new s-triazine species was observed in the degradation mixtures which, together with M1, appeared immediately upon photolysis and continued to accumulate in the degradation mixture throughout the entire study duration. This is in contrast to the behaviour of the recently identified degradation product of Irgarol-1051, 3-[4-tert-butylamino-6-methylthiol-s-triazin-2-ylamino]- propionaldehyde (M2), which was only detected in the degradation mixture after a long induction period. High-resolution tandem mass spectrometric analysis hinted that the new degradation product (M4) may possess a terminal alcohol and is likely to be an N-allylic alcohol derivative of M1. This suggests that M4 may, indeed, be a precursor of M2 via redox transformation at its N-allylic alcohol functionality.     

Application of the <Superscript>137</Superscript>Cs tracer technique to study soil erosion of alpine meadows in the headwater region of the Yellow River

The ¹³⁷Cs tracer technique was used to study soil erosion of alpine meadow grassland in two small river basins in the headwater region of the Yellow River. The results show that the levels of ¹³⁷Cs in soil samples from this alpine meadow vegetation zone exhibit an exponential distribution, generally within a depth of approximately 20 cm. Due to strong winds, freeze-thaw cycles and water, soil erosion was found to be stronger on the upper slope than on the lower slope, and except for the slope crest, the intensity of soil erosion at other sites was as follows: upslope < midslope < downslope. There was a significant negative correlation between the intensity of soil erosion and the extent of alpine meadow vegetation cover (P < 0.01). The mean soil erosion modulus exhibited a linear reduction trend with an increase in vegetation cover, and the correlation coefficient R ² was ≥ 0.997. The higher the degradation degree of the alpine meadow grassland, the greater is the soil erosion. The mean erosion modulus in the severely degraded meadow zone was 2.23 times greater than the one in the slightly degraded zone, and the maximum erosion modulus reached 2.96 × 10⁶ kg/km²/a.     

Sea transport of animal and vegetable oils and its environmental consequences

The increasing production––and therefore sea traffic––of vegetable oils has regularly led to spillages during the past 40 years. The accident of Allegra, on October,1st, 1997, in the English Channel gave rise to a spillage of 900 tonnes of palm nut oil. The drift of this solid vegetable oil was followed by aerial observations. Samples of oil were collected in order to analyse its chemical evolution. This study, associated with several bibliographic cases of pollution by non-petroleum oils, shows that drifting oils can mix with floating material to sink or form a crust. They can also be oxidized or disperse and/or be degraded by bacteria. They may also polymerise. The coating properties of vegetable oils act as crude oils to affect sea life, tourism and yachting. As a result, it is necessary to quickly collect the oil after a spillage, using usual equipment (booms and pumps).     

Differences in the mode of incorporation and biogenicity of the principal aliphatic constituents of a Type I oil shale

Compound-specific stable carbon isotope (δ ) measurements on the aliphatic hydrocarbons released from an immature Tertiary oil shale (Göynük, Turkey) via hydropyrolysis, following solvent extraction and a milder hydrogenation treatment, have further highlighted that significant compositional differences may exist between the principal aliphatic constituents of the solvent extractable (bitumen) phase and the insoluble macromolecular network (kerogen) comprising the bulk of sedimentary organic matter. Whilst inputs from diverse sources; including algae, bacteria and terrestrial higher plants, were implied from analysis of solvent-extractable alkanes, the much larger quantities of kerogen-bound n-alkyl constituents released by hydropyrolysis had a uniform isotopic signature which could be assigned to (freshwater) algae. Remarkably, the aliphatics bound to the kerogen by relatively weak covalent bonds, liberated via catalytic hydrogenation, appeared to comprise mainly allochthonous higher plant-derived n-alkanes. These results provide further compelling evidence that the molecular constituents of bitumen and, indeed, of low-yield kerogen degradation products, are not necessarily reliable indicators of kerogen biogenicity, particularly for immature Type I source rocks. The isotopic uniformity of aliphatic n-hydrocarbons released by the high-conversion hydropyrolysis step for the ultralaminae-rich Göynük oil shale, lends further support to the theory that selective preservation of highly resistant aliphatic biomacromolecules is an important mechanism in kerogen formation, at least for alginite.     

Verhalten ausgewählter Arzneimittel bei der künstlichen Grundwasseranreicherung – Eliminierung und Effekte auf die mikrobielle Besiedlung

Behaviour of Some Pharmaceuticals during Artificial Groundwater Recharge – Elimination and Effects on Microbiology The behaviour of bezafibrate, carbamazepine, clofibric acid, diclofenac, ibuprofen, and gemfibrozil during artificial groundwater recharge was investigated with different test systems simulating field conditions. The given concentrations of the pharmaceuticals were 100 μg/L in the influent of the systems. Concentrations in the influent as well as in the effluent were measured by GC‐MS. These column experiments indicated a significant elimination of bezafibrate, diclofenac, and ibuprofen (60 to 80%) during slow sand filtration. The results showed a moderate elimination of clofibric acid and gemfibrozil (40 to 60%) but a rather low elimination of carbamazepine (<40%). The adaptation times until the elimination processes started were about 5 days. Only the elimination of carbamazepine needed a lag phase up to 17 days. Additional column experiments with groundwater model systems indicated a high persistence of pharmaceuticals under aerobic and anaerobic groundwater conditions. The elimination was less than 20%. Only diclofenac was eliminated with rates between 60% and 80% in aerobic systems and between 40% and 60% in anaerobic systems. Analysis of eubacterial 16S‐rDNA by PCR and DGGE demonstrated changes in the microbial community structure in slow sand filters after application of pharmaceuticals. Adaptation processes may cause these changes, e.g. the appearance or disappearance of single species. Also differences between the populations of water and of the solid phase in slow sand filters could be demonstrated by DGGE pattern.