陕西潼关县桐峪金矿区水文地质特征

简要叙述了小秦岭金矿田桐峪矿区水文地质特征、地下水的主要赋存形式、富集规律，以及补给、迳流、排泄条件等。     

A numerical solution to seepage problems with complex drainage systems

Seepage problems with complex drainage systems are commonly encountered in civil engineering, with strong non-linearity. A numerical solution based on the Finite Element Method combining the substructure technique with a variational inequality formulation of Signorini’s type is proposed to solve these problems. The aims of this work are to accurately characterize the boundary conditions of the drainage systems, to reduce the difficulty in mesh generation resulting from the drainage holes with small radius and dense spacing, and to eliminate the singularity at the seepage points and the resultant mesh dependency. Numerical stability and robustness of the proposed method are guaranteed by an adaptive procedure for progressively relaxing the penalized Heaviside function associated with the formulation of the discrete variational inequality. Two challenging numerical examples are presented to validate the effectiveness and robustness of the proposed method.     

登陆台风Matmo(2014)北侧对流雨带的触发和发展过程

登陆台风Matmo（2014）北侧弱回波区突发多条强对流雨带,造成严重影响。本文利用NECP/NCAR的FNL（Final）再分析资料,地面自动站加密观测资料、雷达拼图资料等对台风北侧连续出现的3条对流雨带的触发和发展过程进行研究。结果表明:初始对流是在弱的对流不稳定和条件对称不稳定条件下,由锋面强迫和地形抬升作用共同触发。接二连三发生的3条对流雨带是在台风北部高湿环境,长时间稳定的水汽辐合,明显的对流不稳定,局部弱条件对称不稳定条件下,由近地面辐合线在辐合稳定并加强后触发的,有利的环境和多层不稳定的叠加有利于雨带的发展和维持。先后触发对流雨带的3条辐合线在发生位置上相当接近。辐合线的形成一方面由海陆下垫面差异、江苏和山东南部海岸线曲率、台风风速随半径分布特点所决定;另一方面,辐合线2和3的形成还与它们北侧对流雨带的冷出流密切相关。对流带上的强降水中心往往对应着稳定的辐合中心,辐合中心主要位于风速大小梯度明显的位置上。而辐合线上的风速梯度主要受海岸线、地形附近的降水分布影响。     

波、流共同作用下的泥沙起动

对波、流共存时的床面剪切力及摩阻系数等作了探讨,根据泥沙起动试验,建立了泥沙起动Shields曲线,导出了波、流共同作用下层流和紊流时的泥沙起动公式和起动波高、起动水深.     

Ni-Cr系与Mn系低合金钢耐点蚀性能的比较

通过极化试验与模拟闭塞腐蚀电池试验对常用的两类低合金船体结构钢耐蚀性能做了比较，并结合实船使用情况对两类钢的耐蚀性能做了较全面的评价。结果表明，Ni-Cr系钢的点蚀诱发敏感性低于Mn系钢；在模拟长期挂片时Ni-Cr钢的点蚀扩展速率反比№钢大，而实船使用情况是Ni-Cr系钢的耐蚀性能远比Mn系钢好。     

Convective initiation by topographically induced convergence forcing over the Dabie Mountains on 24 June 2010

The initiation of convective cells in the late morning of 24 June 2010 along the eastward extending ridge of the Dabie Mountains in the Anhui region,China,is studied through numerical simulations that include local data assimilation.A primary convergence line is found over the ridge of the Dabie Mountains,and along the ridge line several locally enhanced convergence centers preferentially initiate convection.Three processes responsible for creating the overall convergence pattern are identified.First,thermally-driven upslope winds induce convergence zones over the main mountain peaks along the ridge,which are shifted slightly downwind in location by the moderate low-level easterly flow found on the north side of a Mei-yu front.Second,flows around the main mountain peaks along the ridge create further convergence on the lee side of the peaks.Third,upslope winds develop along the roughly north–south oriented valleys on both sides of the ridge due to thermal and dynamic channeling effects,and create additional convergence between the peaks along the ridge.The superposition of the above convergence features creates the primary convergence line along the ridge line of the Dabie Mountains.Locally enhanced convergence centers on the primary line cause the initiation of the first convection cells along the ridge.These conclusions are supported by two sensitivity experiments in which the environmental wind(dynamic forcing) or radiative and land surface thermal forcing are removed,respectively.Overall,the thermal forcing effects are stronger than dynamic forcing given the relatively weak environmental flow.     

Channel width—drainage area relations in small basins

The measurement of stream channels in basins less than 3 km² shows compound relations between width and area. Break points in the relations may be attributed to the changing contribution of rapid storm flow and to the effect of bed material size.     

Relative scales of time and effectiveness of climate in watershed geomorphology

Peak rainfalls and peak runoff rates per unit area are comparable over a worldwide spectrum of climates. However, while the magnitude of the external contribution of energy or force in diverse regions is similar, the impact on the landscape varies markedly between regions. Absolute magnitudes of climatic events and absolute time intervals between such events do not provide satisfactory measures of the geomorphic effectiveness of events of different magnitudes and recurrence intervals. Although geomorphic processes are driven by complex sets of interrelated climatic, topographic, lithologic, and biologic factors, the work done by individual extreme events can be scaled as a ratio to mean annual erosion and the effectiveness of such events in forming landscape features can be related to the rate of recovery of channel form or mass wasting scars following alteration by the extreme event. Thus, a time scale for effectiveness may relate the recurrence interval of an event to the time required for a landform to recover the form existing prior to the event. River channels in temperate regions widened by floods of recurrence intervals from 50 to more than 200 years may regain their original width in matters of months or years. In semi-arid regions, recovery of channel form depends not only upon flows but upon climatic determinants of the growth of bottomland vegetation resulting in variable rates of recovery, on the order of decades, depending upon coincidence of average flows and strengthened vegetation. In truly arid regions the absence of vegetation and flow precludes recovery and the width of channels increases in drainage areas up to 100 km² but remains relatively constant at larger drainage areas. Area as well as time controls the effectiveness of specific events inasmuch as the likelihood of simultaneous peak discharges or rainfalls and large areas is less, particularly in arid regions where events spanning areas of more than several thousand km² are extremely rare if experienced at all. To some extent a decrease in area in a humid region is comparable with a regional change from humid toward more arid climate reflected in the increase in importance of episodic as contrasted with more continuous processes. Exceedingly rare floods of extreme magnitudes, estimated recurrence intervals of 500 years or longer, may exceed thresholds of competence otherwise unattainable in the ‘normal’ record resulting in ‘irreparable’ transformations of valley landforms. Denudation of hillslopes by mass wasting during relatively rare events can also be related to mean rates of denudation and to recovery of hillslope surfaces after scarring by different kinds of landslides. Measured recovery times described in the literature vary from less than a decade for some tropical regions to decades or more in temperate regions. Recurrence intervals of high magnitude storms which trigger mass wasting range from 1 to 2 years in some tropical areas, to 3 or 4 per hundred years in some areas of seasonal rainfall and to 100 or more years in some temperate regions. The effectiveness of climatic events on both hillslopes and rivers is not separable from gradient, lithology or other variables which control both thresholds of activity and recovery rate.     

Modelling drainage headwater development

Processes operative in the divideward sections of streams and channels are reviewed, and the effects of their action over long periods of time are modelled for insight into long-term valley head development. Upper valley axis profiles eventually become concave upwards over time but may show earlier convexity and convexo-concavity. After any particular length of development different upper valley axis forms can exist in areas of different climate and hydrological response characteristics.     

Watershed geochemistry: The control of aqueous solutions by soil materials in a small watershed

Laboratory and field data indicate that the aqueous geochemistry of a small watershed in siliceous materials is largely determined by reactions between soil and water. For dissolved SiO₂, Ca⁺², K⁺, Na⁺, a reversible steady state is achieved in the soil within hours. The solute concentrations are in equilibrium with kaolinite, the end-product in the local weathering sequence. The processes occur in a drainage basin in which solution activities are the predominant form of erosion.