Garnets from diamond deposits in China and in the Arkhangelsk diamondiferous province

The morphology and chemical composition of garnets from principal deposits in China and in the Arkhangelsk Province consisting of kimberlites of various mineral types have been examined. The morphology of garnets (300 specimens) from the V. Grib pipe was examined, in which crystal fragments and irregular grains predominate, and dissolution traces are common. Distribution of types of garnet coloration is typical of kimberlites: lilac-violet and red garnets of ultramafic rock association are preponderant, and the proportion of yellow-orange garnets is rather high, while brown garnets are very rare. The garnet preservation degree is very low, which is related to their high primary fracturing due to cataclasis. Grains with finely matted surfaces are preponderant (90%) reflecting their high corrosion alterations. The chemical composition was determined in 56 garnet speciments from the Grib pipe. Garnets from lherzolitic and eclogitic rock types were found and garnets from magnesium and ilmenite ultramafics are present; there are no garnets from eclogites, but garnets from diamondiferous rock associations occur. The investigations demonstrated that garnets from lherzolite rock association are preponderant in kimberlites from China, as well as from other regions, while garnets from the harzburgite-dunite and from diamondiferous rock associations are rare. Garnets belonging to the graphitepyrope depth facies were also found.     

Le Capelinhos (Faïal,Açores) vingt ans après son éruption: le modèle éruptif «surtseyen» et les anneaux de tufs hyaloclastiques

Phreatomagmatic structures are of two kinds: maars and tuff-rings. Data given by records of Capelinhos activity (Faïal, Açores, 1957–1958), by structures at west point of Faïal island, and by palagonitic breccias of Velay and Cantal areas (France) lead to relate hyaloclastic tuff-rings and shallow subaquatic («surtseyan») eruptions. It is possible to precise causes, characteristics, and mechanism of formation of tuff-rings.     

格尔木河水质现状及生态风险评估

为了了解经济迅速发展背景下格尔木河流域水体中痕量元素分布、水环境质量现状和生态风险,对格尔木河9个采样点水样21种痕量元素的分布及相关性进行了分析,以Cu、Zn、Hg、Cd、Cr和Pb为目标重金属,评估了格尔木河水质现状及生态风险。结果表明：重金属Pb浓度在所有水样中均低于检出限,其它痕量元素浓度在0.001(Cd) ~ 6297.013(Sr) μg?L<sub><sup>-1</sup></sub>范围变化。根据相关性分析,推测格尔木河水体中Li、Sc、Ti、V、Cu、Ge、Rb、Sr、Mo、Cd来源可能相同。采样点水样6种重金属浓度均达到地表水环境质量I类的标准。采用5种方法评价了格尔木河水质现状,结果表明研究区水质处于无污染的理想状态。格尔木河重金属引发的潜在生态风险处于低风险水平(生态风险指数变化范围为0.35~0.68)。     

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Metals in lacustrine sediment have both anthropogenic and natural sources. Because of intensified human activities, the anthropogenic input of metal elements has exceeded the natural variability. How to distinguish the anthropogenic sources in lake sediments is one of the tasks in environmental management. The authors present a case study, which combined the geochemical and statistical methods to distinguish the anthropogenic sources from the natural background. A 56 cm core (core DJ-5) was collected from Dongjiu Lake, Taihu Lake catchment, China. The concentration distributions of Al, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, Ti, V and Zn in core DJ-5 indicated that Dongjiu Lake had serious Cd pollution, and the concentrations of Cr, Cu, Pb, Mn and Zn had also exceeded the Chinese State Standards of Soil Environmental Quality in the upper layer of the core. Using Al as a reference element, the other metals were normalized and compared with their baselines to calculate the enrichment factors (EFs). The principal component analysis (PCA) of metal concentrations was performed using ViSta6.4. The results of EFs and PCA indicated that the concentration variations of Cd, Cu, Pb, Mn and Zn were mainly caused by the anthropogenic sources, and the concentration variations of Cr and Ni were influenced by both the anthropogenic and natural factors, while the other metals were mainly derived from the natural sources. Intensified human activities within the lake catchment area resulted in the increase of heavy metal inputs directly and the acceleration of erosion which caused other metal elements to deposit in the aquatic environment. The results of this work will be useful in probing changes forced by humans in the lake environment and in adjusting human activity in restoring the lake environment.

电梯机房雷击电磁脉冲空间屏蔽措施

以一个位于高层建筑物顶部的电梯机房作为研究对象,结合其地理位置、闪电环境和雷电防护现状,进行了雷击电磁脉冲分析.对于电梯机房的各类屏蔽条件,分别对机房内设备的感应电压进行了相应的计算分析,给出了电梯机房需要采取的屏蔽措施和其它防护措施,得出结论:①无论雷电击中电梯机房还是击中建筑物附近,若无屏蔽措施均将影响电梯正常运行;②位于建筑物顶部的电梯机房在做好基本防雷措施的基础上,还需要采取金属网格(钢筋半径为0.002 m、网格宽度为0.01 m)进行屏蔽.     

河南烟区烤烟生育期地表温度日较差变化对烤烟化学品质指标的影响

利用19612013年河南烟区64个气象站逐日0 cm地表温度资料和20032012年烤烟化学成分数据,通过数理统计方法分析了烤烟生育期地表温度日较差(简称地温差)的变化对烤烟化学品质指标的影响。结果表明,河南省烟区烤烟化学成分与生育期地温差关系密切。河南烟区烤烟生育期地温差整体呈显著缩小趋势,下降趋势明显区域主要出现在三门峡、洛阳、平顶山、许昌、漯河和南阳。仅烤烟大田期和旺长期地温差存在突变点,且突变点基本上出现在20世纪80年代初期前后,地温差在显著突变前对烤烟化学成分影响显著。河南烟区烤烟下部叶化学品质指标的变异系数较大,空间差异更为显著。未来可能进一步缩小的地温日较差,将会导致上部叶总糖、还原糖、蛋白质含量减少,钾氯比含量增加;中部叶的氮碱比、糖碱比减少,烟碱、钾含量增加;下部叶两糖比增加。     

高精度实时位置服务的格网化VRS技术

为确保基于VRS的网络RTK定位性能,提高VRS的服务质量,本文系统地构建了面向海量并发用户服务的格网化VRS方法,建立了VRS格网的两种划分方法。顾及电离层延迟的空间相关特性,选定中纬度和低纬度两个区域的CORS网络进行试验测试,分析并确定不同区域条件下,格网化VRS的有效服务间距。结果表明:在中纬度地区和低纬度地区,格网VRS有效服务间距限值分别为12 km和7 km。与非格网化VRS(以标准定位服务结果建立)相比,可大幅度降低VRS产生和计算负荷,有效提升服务器对海量用户的服务能力。     

新型冠状病毒肺炎疫情可视化进展与分析

新冠肺炎疫情期间,疫情数据成为民众关注的重点,涌现出了大量可视化图件,及时地向公众传达着疫情的数量信息和时空分布及变化,帮助大众快速了解疫情当前状况、推断发展趋势.本文从疫情数据可视化表达内容的维度出发,分析不同可视化的表达形式以及其对疫情数据的加工程度,结合示例把可视化分为"1阶"、"2阶"和"多阶",并分析各自表达...     

湖泊藻型富营养化控制——技术、理论及应用

湖泊富营养化防治走过了从控制营养盐、直接除藻、到生物调控、生态工程及生态恢复等艰难历程,各国为此投入了巨额资金、然而收效甚微,富营养化依然是全球性重大水环境问题。回顾和分析富营养化湖泊治理研究与实践的成功经验与失败教训,无疑将有助于采取更切实可行的技术有效控制湖泊富营养化。综观全球营养养化治理研究成果,不难看出,富营养化是一个典型的生态问题,生态问题只有用生态学方法解决。在全湖性富营养化难以快速根治的情况下,如何集中技术优势和有限财力,优先解决对人类生活影响较大的局部水域富营养化问题,逐步修复受损的湖泊生态系统,提高水体自净能力、改善水体环境质量并建立湖泊健康生态系统。