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High-efficiency calculation method for watershed rainfall-runoff routing using one-dimensional dynamic wave equations

Efficiency in solving the Saint-Venant equations for watershed rainfall-runoff routing is important in flood hydrology. This paper presents a high-efficiency numerical solution of one-dimensional dynamic wave equations (HEDWE) for watershed rainfall-runoff routing, in which the full momentum equation is written as a quadratic equation with only one unknown variable Q, water depth is derived from the continuity equation using the two-step predictor-corrector method, and the discrete scheme is the explicit upwind scheme. The results of numerical tests showed the HEDWE approach has several major advantages. 1) It is a stable numerical method, even for an initially dry area. 2) Its computational efficiency is higher than 4.76E+05 times/s. 3) It can be used for overland flow, river flow, and combinations thereof. The primary disadvantages of the HEDWE approach are its unsuitability for rapidly varying flow, such as dam-break floods.     

Hydromechanical behavior of unsaturated soil with different initial densities over a wide suction range

Acta Geotechnica - Many civil engineering projects are related to hydromechanical behavior of unsaturated soils over a wide suction range, which was investigated by imposing suctions on clayey silt...     

长河煤矿充水因素分析及防治水措施

长河煤矿为地质构造中等复杂区，其矿区地质及水文地质条件表明，地表水、直接充水含水层煤系砂岩裂隙水、老窑水、构造断裂带水都可构成该矿井开采的充水因素，且其涌水量大小与大气降水关系密切。针对矿井开采的具体情况提出了一系列的防治措施，并取得了良好的效果，对煤矿水害的防治有一定的指导意义。     

波伏棱（Povlen）型羟基纤蛇纹石的谱学研究

波伏棱型羟基纤蛇纹石是波伏棱型纤蛇纹石矿物的新变种,本文报导它的吸收光谱、红外光谱、穆斯堡尔谱、电子顺磁共振谱和核磁共振谱。 研究表明,吸收光谱是Fe~(3 )和Fe~(2 )的晶场跃迁以及Fe~(2 )→Fe~(3 )的荷移跃迁引起的;红外光谱是OH和Si-O的伸缩振动、OH转动以及Mg-O和Si-O的弯曲振动引起的;穆斯堡尔谱是Fe~(2 )_(八面体)、Fe~(3 )_(八面体)和Fe~(3 )_(四面体)引起的;电子顺磁共振谱是Mn~(2 )_(八面体)、Fe~(3 )_(八面体)和Fe~(3 )_(四面体)引起的;核磁共振谱是管道水,镁八面体和硅氧四面体上的OH引起的;矿物加热到825℃时,结构开始破坏并出现镁橄榄石相。 此外,本文还解释了该蛇纹石颜色的本质,阐明了上述过渡金属离子和OH在该矿物中的结构环境。     

Surface-deformation monitoring in the permafrost regions over the Tibetan Plateau,using Sentinel-1 data

Differential Interferometric Synthetic Aperture Radar(D-In SAR) has been widely used to measure surface deformation over the Tibetan Plateau. However, the accuracy and applicability of the D-In SAR method are not well estimated due to the lack of in-situ validation. In this paper, we mapped the seasonal and long-term displacement of Tanggula(TGL) and Liangdaohe(LDH) permafrost regions with a stack of Sentinel-1 acquisitions using the Small Baseline Subset In SAR(SBAS-In SAR) method. In the TGL region, with its dry soils and sparse vegetation, the In SAR-derived surface-deformation trend was consistent with ground-based leveling results; long-term changes of the active layer showed a settlement rate of around 1 to 3 mm/a due to the melting of ground ice, indicating a degrading permafrost in this area. Around half of the deformation was picked up on monitoring, in contrast with in-situ measurements in LDH, implying that the D-In SAR method remarkably underestimated the surface-deformation. This phenomenon may be induced by the large soil-water content, high vegetation coverage, or a combination of these two factors in this region. This study demonstrates that surface deformation could be mapped accurately for a specific region with Sentinel-1 C-band data, such as in the TGL region.Moreover, although the D-In SAR technology provides an efficient solution for broad surface-deformation monitoring in permafrost regions, it shows a poor performance in the region with high soil-water content and dense vegetation coverage.     

基于共相思想的新一代组件式GIS研究与开发

在简要回顾GIS软件和组件式GIS的发展之后，经过对比分析，提出同时支持两大主流开发平台——．NET和Java EE是新一代GIS组件的必然选择，并对可能实现的几种模式加以讨论．提出基于“共相”思想的C＋＋扩展模式是最为彻底和完关的解决方案，最后介绍在“共相”思想指导下的新一代组件式SuperMap GIS的设计和开发。     

Stress distribution characteristic analysis and control of coal and gas outburst disaster in a pressure-relief boundary area in protective layer mining

Coal and gas outburst disasters in coal seams are becoming more serious as coal mines extend deeper underground in China. Furthermore, the protective coal seam mining technology featured by economic efficiency has been proven to be the most effective and widely applied method for the prevention of coal and gas outburst disasters. However, the determinations of the protective area coal and gas outburst prevention in a pressure-relief boundary area are fundamental issues that research should be focused on. The technical method for determining stress distribution in pressure-relief boundary area during protective coal seam mining is put forward in this paper. The method is based on a stress-seepage coupled relationship within a gas-containing coal seam. The method includes complex lab experiments and on-site measurements at the Qingdong Coal Mine. The final data illustrate that the permeability and vertical stress in the pressure-relief boundary area of the coal sample form a negative exponential function relationship. Additionally, the permeability of the coal sample within the abovementioned area is significantly different compared with that located at the center of the pressure-relief area. In the pressure-relief boundary area, the gas pressure distribution gradient is 0.0375 MPa/m, while the vertical stress distribution gradient registers 0.56 MPa/m. Under this condition, coal and gas outburst disasters are prone to be triggered. Therefore, effective precautions against coal and gas outburst disasters can be put forward in accordance with stress distribution characteristics within the abovementioned “boundary area.”     

Geochemical distribution and removal of As,Fe, Mn and Al in a surface water system affected by acid mine drainage at a coalfield in Southwestern China

The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide minerals in the coal seam, the initial composition of the groundwater and the water–rock interaction. The AMD is characterized by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca²⁺ and SO₄ ²⁻ are the dominant cation and anion in the AMD, respectively, while Ca²⁺ and HCO₃ ⁻ are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge. Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental problem. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Accumulation of heavy metals in wild commercial fish from the Baotou Urban Section of the Yellow River,China

In this work we studied the accumulation of heavy metals in nine species of fish with different life and feeding habitats which are native and major commercial fish in the Baotou Urban Section of the Yellow River. The results showed that the concentration of heavy metals was significantly dependent on fish species; the pollution index of heavy metals in different species were ranked as Hemiculter leucisclus > Carassius auratus auratus > Hemibarbus maculatus > Megalobrama amblycephala > Abbottina rivularis > Cyprinus carpio > Squaliobarbus curriculus > Perccottus glehni > Saurogobio dabryi. Product–moment correlation coefficients among the metal pairs Pb–Zn, Cu–Cd, Cu–Zn, Cu–Pb, Pb–Cd, and Zn–Cd revealed there was no competitions between metals in each tissue. Correlations between heavy metal concentrations and fish length or weight indicated that accumulation of the heavy metals by the different fish species was related to their surrounding environments and their life and feeding habitats. According to the mean bioconcentration factors (BCFs), the heavy metal concentrations in these nine species were ranked Zn ≫ Cu > Cd ≈ Pb. In this work, the bioaccumulation factors (BAFs) were developed by using the sum of exchangeable and bound-to-carbonate heavy metals as Cs values. It was found that BAFs better reveal the accumulation characteristics of the heavy metals in the fish, which might provide an effective method for assessing bioaccumulation of heavy metals.