Quantification of Water Content and Speciation in Synthetic Rhyolitic Glasses: Optimising the Analytical Method of Confocal Raman Spectrometry

Quantification of water content in silicate glasses is of vital significance in understanding magma evolution and metamorphic anataxis. Here we provide a method for the determination of total dissolved water content and water speciation in silicate melts by confocal laser Raman spectrometry based on a set of hydrous rhyolitic glasses. A series of alumino-silicate glasses with water contents from 0.33 to 9.05% m/m were synthesised in a piston cylinder apparatus. Synchrotron-FTIR mapping shows that these glasses have relatively homogeneous distributions of dissolved water. Total water contents of the glasses were precisely measured by TC/EA-MS and FTIR. Both external and internal calibration were established for the quantitative analysis of water content and water speciation in the silicate glasses based on excellent linear correlation between total dissolved water content and integrated area of the water Raman band. Furthermore, by decomposing the total water Raman bands into four Gaussians components, the relative concentration of water speciation (OH groups and molecules H₂O_m) dissolved in the glasses was determined with a similar trend to water speciation data derived from FTIR. We suggest that the relative concentration of water speciation can be estimated in rhyolitic glasses with 4–8% m/m H₂O. Our work provides an accurate method to determine total water content and a potential tool to limit the relative concentration of water speciation dissolved in silicic glasses.     

In-situ formation of perylene in lacustrine sediments and its geochemical significance

Acta Geochimica - To identify the possible sources and formation mechanism of perylene in sediments, temporal trends of perylene and other polycyclic aromatic hydrocarbons, as well as the organic...     

Investigating the impacts of typhoon-induced floods on the agriculture in the central region of Vietnam by using hydrological models and satellite data

Flooding associated with landing tropical cyclones (TCs) is one of the major natural hazards in the coastal region of Vietnam. Annually, approximately 5 or 6 TCs make landfall in Vietnam, bringing heavy rains and inducing flooding, particularly to the central coastal region because of its topography and geographic configuration. This study focuses on the modelling of typhoon-induced floods that have resulted in widespread damage to agriculture over the central Thua Thien Hue Province of Vietnam by coupling two well-known hydrological models, KINEROS2 and HEC-RAS (Daniel et al. in Open Hydrol J 5(1), 2011), and using GSMaP (Global Satellite Mapping of Precipitation) data as the satellite rainfall input. Landsat imagery and GIS are also used for mapping and analysing the inundated areas. The discharge and water level from the KINEROS2 and HEC-RAS models displayed acceptable results for the floods modelled from three selected typhoons; both the Nash–Sutcliffe simulation efficiency coefficient (NSE) and the coefficient of determination (R²) were greater than 0.6. The simulated inundation maps of these typhoon-induced floods were compared with those extracted from the Landsat imagery to assess consistency. The result revealed a similar spatial extension of the inundated agricultural areas. This information, together with the forecasted TC movements and associated rainfalls, will be helpful to plan methods for mitigating potential typhoon-induced flooding and damage, particularly damage to agricultural regions.     

MST—88型多路测温仪

ＭＳＴ－８８型多路测温仪采用ＰＣ－１５００（Ａ）袖珍机作处理机，选用集成电路ＡＤ５９０作温度传感器，对１０路温度参数轮流采集，对采集的数据进行了线性校正，以人－机对话的方式，使野外采集温度参数实现了自动巡测，打印，显示，外存及数据处理。     

微生物参与下的水/粒界面吸附反应研究进展

回顾了近年来微生物存在下的水/粒界面吸附反应研究进展，包括微生物对金属阳离子的吸附、矿物微粒对微生物的吸附和微生物参与下的水/粒界面吸附；目前，这些吸附反应的定量化模型研究主要有体积分配关系和表面络合模型两种方法。其中，体积分配关系可从野外直接测得；而表面络合模型是采用不受溶液条件变化影响的准热力学常数来描述表面化学反应，能外推至实验室无法直接模拟的条件。随着人们对微生物在环境中重要性认识的加深，微生物参与下的水/粒界面吸附和可预测吸附程度的定量化模型受到人们越来越多的重视。     

THE ADVANCES IN OPERATIONAL NUMERICAL WEATHER PREDICTION AT NATIONAL METEOROLOGICAL CENTER IN CHINA

Since 1982, several modifications in the operational model in National Meteorological Center(NMC) of China have been made, such as the adoption of the lateral boundary condition formulated byHovermal, Shuman's economic time difference scheme in the 5-layer Northern Hemispheric Model,and the replacement of the convective adjustment scheme by Kuo's cumulus parameterization scheme1974) in the 5-layer FLM. Owing to these modifications, both the objective and subjective verificationsof the prediction show that the accuracy of operational NWP has been significantly improved.Finally, applications of NWP Products are briefly summarized and future prospects are given.     

极端降雨事件对南方红壤区径流和输沙的影响——基于赣江支流濂江上游流域的长序列分析(1984—2020年)

为探究极端降雨对南方红壤区流域水沙的影响,本文基于江西省鄱阳湖水系赣江上游濂江流域1984—2020年逐日降雨量、径流量和输沙量数据,使用95百分位法计算极端降雨,并采用最小事件间隔时间法分割降雨事件,综合应用Pettitt检验和线性回归方法对水沙突变、影响因子进行定量分析。结果表明:(1)发生极端降雨事件的时期是流域泥沙输出的关键时期,极端降雨对输沙量的贡献率达85.58%～87.79%,而对径流量的贡献为38.33%～43.42%。(2)在极端降雨情景下,年径流量从1984—1995年的209.21×10⁶ m³下降到1996—2020年的165.23×10⁶ m³,而年输沙量从1984—1995年的3.65×10⁴ t增加到1996—2020年的12.8×10⁴ t,相比于1984—1995年,1996—2020年的极端降雨所产生的径流量和输沙量占比有缩小趋势,分别表现为从43.42%到38.33%和从87.79%到85.58%。(3)极端降雨情景下...     

浅谈地质科技档案资料的有偿使用

地质科技档案是宝贵财富,由于封闭式管理模式没有发挥应有的作用,文章通过对地质科技档案在市场经济体制下,实行有偿使用的必要性及其意义作了简要论述,探讨有偿使用的方法,联系实际说明有偿使用地质科技档案的社会效益和经济效益,展示了深化地质科技档案改革给地勘单位带来活力与前景。     

东台沟实验流域降水氧同位素特征与水汽来源

运用环境同位素技术研究水循环中水分子组成发生的微观变化,是兴起于20世纪中期研究宏观、微观水文过程机理的新技术。研究流域降水同位素时间和空间变化规律以及与降水要素的相关关系,对于研究流域水资源属性具有重要的理论与实践意义。本文以北京市怀柔区汤河口镇东台沟实验流域为研究对象,研究了该流域2003年7月至10月降水氧同位素含量及降水的时空变化,分析了降水δ¹⁸O与降水量、高程及空气湿度的关系,评估了雨量、高程及空气湿度等因子对降水过程的影响及作用,阐明了其间实验流域降水δ¹⁸O的时空分布规律,并得出实验流域在实验期间降水的主要水汽来源为由东南向西北方向。     

IGCP-649 Project “Diamonds and Recycled Mantle”

正The IGCP-649 project"Diamonds and Recycled Mantle"is an International Geosciences Program sponsored by UNESCO and IUGS,supporting the scientific research on ultrahigh pressure and highly reduced minerals in ophiolitic peridotite and chromitite.Ophiolites are 5-to 10-km-thick fragments of ancient ocean lithosphere emplaced on continental margins,and provide3-dimensional exposures to examine the internal structure,