Groundwater circulation and hydrogeochemical evolution in Nomhon of Qaidam Basin,northwest China

In this study, analysis of hydrogeological conditions, as well as hydrochemistry and isotopic tools were used to get an insight into the processes controlling mineralization, recharge conditions, and flow pattern of groundwater in a typical arid alluvial-lacustrine plain in Qaidam Basin, northwest China. Analysis of the dissolved constituents reveals that groundwater evolves from fresh water (TDS =300–1000 mg/l) to saline water (TDS ≥5000 mg/l) along the flow paths, with the water type transiting from HCO ₃?Cl–Na ?Mg to HCO ₃?Cl–Na, and eventually to Cl–Na. Groundwater chemical evolution is mainly controlled by water–rock interaction and the evaporation–crystallization process. Deuterium and oxygen-18 isotopes in groundwater samples indicate that the recharge of groundwater is happened by meteoric water and glacier melt-water in the Kunlun Mountains, and in three different recharge conditions. Groundwater ages, estimated by the radiogenic (³H and ¹⁴C) isotope data, range from present to Holocene (～28 ka). Based on groundwater residence time, hydrogeochemical characteristics, field investigation, and geological structure distribution, a conceptual groundwater flow pattern affected by uplift structure is proposed, indicating that shallow phreatic water is blocked by the uplift structure and the flow direction is turned to the northwest, while high pressure artesian water is formed in the confined aquifers at the axis of the uplift structure.     

Hydromechanical modelling of the SEALEX experiments

Numerical modelling of coupled physical processes in bentonite–sand mixtures under the geological conditions is significant for designing and constructing sealing systems in deep underground repositories for highly radioactive nuclear waste. Within the framework of DECOVALEX 2015, Task A, this work presents the model validation of OpenGeoSys by numerical modelling of coupled hydromechanical (HM) processes in bentonite–sand mixtures. Parameters used in the HM model were determined by modelling the laboratory tests of the sealing experiment (SEALEX). Afterwards these parameters were applied for the modelling of a small-scale mock-up test considering the influence of technological gap and incidental fail of the seal in the sealing system. In order to investigate the availability of employing these HM parameters and numerical models directly to field predictions, the modelling results and measured data of an in situ SEALEX experiment were analysed comparatively. The modelling results reproduced well the main features in HM behaviour of the compacted bentonite–sand mixture, which denotes that the adopted HM models and parameters are adequate for describing the HM processes in the sealing system. It is necessary to take the elastoplastic behaviour and evolution of the permeability of bentonite–sand mixtures into account when using the adopted models to reproduce the HM processes of a sealing system.     

Approaches for Monitoring and Assessment of Ecological Benefits of National Key Ecological Projects

In recent decades, due to the combined effect of human activities and climate change, the ecosystem of our country has been continuously degraded, seriously affecting the sustainable economic and social development. In order to protect and recover the ecosystem, China has invested heavily in launching a series of key ecological programs and projects including North Shelter Forest Program, Grain for Green Project and integrated ecosystem management of rock desertification. How to comprehensively and timely grasp the ecological effects and existing flaws of the implementation of key ecological projects so as to scroll the implementation of ecological projects and ensure the implementation effect of the projects, and promote the follow-up ecological engineering deployment of being scientific and space-oriented is a major imperative for the country. Therefore, the National Key Research and Development Program of China set up the project of “Monitoring and Assessment of Ecological Benefits of Key Ecological Engineering in China”. Through the implementation of this project, we will establish an indicator system for monitoring and evaluating the ecological benefits of key ecological projects, developing various technical systems for monitoring and evaluating the ecological benefits of key ecological projects, quantitatively evaluating the ecological benefits of key ecological projects, and concise the technical approaches to enhancing ecological benefits. We will provide a scientific basis for future planning and management of key ecological projects.     

Design and implementation of webGIS-based GPS vehicle monitoring system

This paper develops a WebGIS-based GPS vehicle monitoring system with typical three-tier application architecture of B/S pattern. It provides ordinary registered users with a valid and convenient means to get access to real-time GPS location information of certain moving vehicles at any place, and further offers a powerful tool for super users to manage user information and remotely monitor those vehicles and provide corresponding services timely if necessary. The system architecture, function modules, key technologies and application interfaces are given. Finally, the validity of our system is demonstrated in practical cases.     

基于模糊综合评判法的地质构造复杂程度评价——以许厂煤矿330采区为例

矿井地质构造是影响煤矿安全开采的首要地质因素。鉴于许厂煤矿330采区构造特征和发育规律不清,为合理安排生产和正确选择采掘方式,在分析整理现有采掘地质资料的基础上,按照400m×400 m把许厂煤矿330采区划分成44个单元,选取了断层密度、断层强度、平面褶皱强度指数、分维值四个定量评价指标,采用模糊综合评判法对3下煤层的构造复杂程度进行了分析评价。评价结果表明:属于Ⅰ类的有25个单元,Ⅱ类的有7个单元,Ⅲ类的有6个单元,Ⅳ类的有6个单元,开采实际揭露情况与评价结果基本一致,基于模糊综合评判法的地质构造复杂程度评价基本可靠,可为矿井的高效安全生产提供一定的指导依据。     

Design considerations for the USNO astrometric optical interferometer

The USNO will undertake the construction and operation of a phase coherent, astrometric, optical interferometer which will be dedicated to the determination of stellar positions and motions. Building upon the experience gained from the MARK III Interferometer at Mount Wilson, the USNO instrument is currently in the very early stages of conceptualization and initial design. An abbreviated account of the experience gained with the MARK III is given. Examples of the issues and possibilities to be addressed in designing the new USNO instrument are outlined. Some background discussion involving interferometric techniques is included.     

Characteristics of observed trace gaseous pollutants in the Yangtze Delta

The significant impacts on air quality and natural resources, such as land and forest, have taken place in Yangtze Delta in the last two decades, resulting from rapidly economic develop-ment in this region. The Yangtze Delta contains many cities and towns…     

西秦岭北缘断裂带东段断层泥的粒度分布和显微构造特征

根据采集的天然断层泥样品，对西秦岭北缘活动断裂带东段的断层泥首次进行了粒度分布和显微构造特征的实验研究。研究结果表明，该断裂带以粘滑运动为主，兼有蠕滑活动，并具张性扭动特征。     

沉积盆地学说的发展及主要的含油气盆地分类

从科学史观出发，介绍了含油气盆地概念及其学说的发展。展示主要的盆地分类方案，论述含油气盆地分类研究在盆的含油气性评价中所具有的重要意义。指出盆地分类研究的发展方向和未来分类方案所应具有的特点。     

梅山铁矿矿浆成因的系统探讨

梅山铁矿在矿床地质特征、成矿流体来源、氧同位素的组成、实验岩石学资料以及稀土元素分布特征等方面，都充分体现了矿浆成因观点的正确性。特别是磁铁矿及其围岩中稀土元素的系统研究，为进一步探讨矿浆成因铁矿提供了新途径