原子掺杂对单元材料结晶能力的影响

2009年我们建立了一个凝结势模型用以预测材料形成单晶体的能力,表明单元体材料(Ni,Al,Cu,Ar,Mg)的结晶能力随凝结势的增大而单调增强.本文将凝结势模型应用于二元材料体系,并结合分子动力学模拟研究了6% Al原子掺杂对于Ni单晶材料结晶能力的影响.模拟结果发现,Al元素的掺杂会大大减弱Ni单晶的结晶能力,在此基础上提出了二元材料体系凝结势的定义,表明凝结势模型可广泛应用于预测二元体材料的结晶能力.     

The effects of wastewater discharges on the functioning of a small temporarily open/closed estuary

Wastewater discharges affect the functioning of small temporarily open/closed estuaries (TOCEs) through two main mechanisms: (1) they can significantly change the water balance by altering the quantity of water inflows, and (2) they can significantly change the nutrient balance and hence the water quality. This study investigated the bio-physical responses of a typical, small TOCE on the east coast of South Africa, the Mhlanga Estuary. This estuary receives significant inflows of treated effluent from upstream wastewater treatment works. Water and nutrient budgets were used together with biological sampling to investigate changes in the functioning of the system. The increase in inflows due to the effluent discharges has significantly increased the mouth breaching frequency. Furthermore, when the mouth closes, the accumulation of nutrients leads to eutrophication and algal blooms. A grey water index, namely the proportion of effluent in the estuary and an indicator of the additional nutrient inputs into the estuary, reached high values (?50%) during low flow regimes and when the mouth was closed. In these hyper-eutrophic conditions (DIN and DIP concentrations up to 457 μM and 100 μM respectively), field measurements showed that algal blooms occurred within about 14 days following closure of the mouth (chlorophyll-a concentrations up to 375 mg chl-a m⁻³). Water and nutrient balance simulations for alternative scenarios suggest that further increases in wastewater discharges would result in more frequent breaching events and longer open mouth conditions, but the occurrence of hyper-eutrophic conditions would initially intensify despite more frequent openings. The study indicates how water and nutrient balance simulations can be used in the planning and impact assessment of wastewater treatment facilities.     

扇形沉积体生长的分形几何特征分析

扇形沉积体是我国内陆及沿海地区中、新生代含油气盆地中的重要油气勘探目标,对其平面分布形态和内部结构参数特征的定量表征是油气勘探部门极为关注的问题。随着分形几何理论在沉积学领域应用的日趋广泛,使人们可从新的角度来考虑这一问题的解决方法。扇形沉积体的生长是一个复杂的非线性动力学过程,且具有分形特征。分维数的大小反映了沉积体外部形态和内部结构的复杂程度,分维数的变化幅度预示着构造和沉积背景的某些信息。将分形和混沌理论相结合,也许是实施扇形沉积体非线性动力学建模和模拟的重要途经之一。     

构造体制转换与流体多层循环成矿动力学

基于成矿系统动力学研究进展的综合分析, 认为构造体制转换与流体多层循环成矿动力学研究是地球科学跨世纪的重要前沿领域之一, 进而提出这一领域的研究主题和关键问题、研究思路及方法, 阐释其重要意义, 指出构造体制转换与流体多层循环成矿动力学研究以构造演化、流体活动及区域地球化学和地球物理不均一性为基础, 通过变形-流动高温高压实验及计算机数值模拟再现成矿作用过程和机理, 解析构造体制转换与流体多层循环成矿动力学特征, 揭示成矿界面时-空演化规律, 建立成矿系统物质和能量交换-反馈耦合成矿的定量模型.这是深化矿床成因认识的重要基础和实现科学找矿的有效途径, 对地球系统科学和大陆动力学的研究也具有重要意义.      

Fluvial response to Weichselian climate changes in the Niederlausitz (Germany)

The last glacial shows large variations in climate, which are reflected in the fluvial record in the Niederlausitz, eastern Germany. The entire sequence resembles the fluvial development in other river basins in northwestern Europe, which show contemporaneous changes in depositional style at the onset of a climatic change. During the Middle and the Late Pleniglacial, permafrost conditions resulted in an episodic river discharge. The presence or absence of vegetation, in combination with such ephemeral stream conditions, determined the type of river during each period. A relatively well-developed vegetation cover on the flood plains during the Middle Pleniglacial resulted in a low sediment yield. In combination with the intermittent discharge, this caused the development of an ephemeral anastomosing river system, a river with stable channels and extensive sandy overbank areas. The decline in vegetation cover at ca. 28 ka BP caused an increase in sediment yield and peak discharges, which resulted in the development of a sandy braided river in adjustment to these new conditions. Following the coldest period at around 20 ka, precipitation was so low that fluvial activity was limited and aeolian deposition took place in the valley. © 1997 by John Wiley & Sons, Ltd.     

从成矿构造动力学探讨脉状金矿床成矿深度

在综述国内外与韧性剪切带有关的脉状金矿床成矿动力学的新近研究成果后,根据成矿控矿构造动力学特征及其与成矿流体运移机制、矿物结晶特点的关系认为矿物结晶发生于地震微破裂导致成矿流体压力骤降后的低压力阶段,由矿物包裹体压力并按静岩压力梯度推算的成矿深度要明显小于矿床的实际成矿深度.本文提出一种新的成矿深度估算方法,其估算的成矿深度与目前大多数脉状金矿床中石英具有明显的韧性变形的特点相吻合.     

海南戈枕韧性剪切带微观构造研究

韧性剪切带的定性－定量分析。能更清晰、直接地揭示构造运动生发发展过程应力、应变的状况。作者对海南戈枕韧性剪切带从显微构造角度作了系统研究工作。通过矿物粒度、形态比统计，在纵横方向上更明确了内部的复杂分带性；通过显微批向构造、矿物组权及变形变晶分析了探讨了构造活动的方式、方向；通过古应力值、剪应变、总位移量、弗林系数的测算，定量表述了该带变形机制及应力、应变速率大小。     

高压超高压变质岩抬升—剥露的一种动力学机制分析

综述了高压超高压变质岩带的基本构造特征，认为运用体粘滞性流变学理论可以很好地解释高压超高压变质岩的发育过程及其抬升－剥露动力学机制。     

关于大陆构造的思考

大陆动力学与全球动力学是当代地学的重在前沿领域。本文在研究青藏高原与周缘盆地的同步演化规律和综合前人最新研究成果的基础上，分析了大陆构造的１０个基本问题，并进一步阐述了层流构造模式，其内容包括：（１）深部层流导致浅部隆陷；（２）层流隆陷构造系统的物质循环过程；（３）大陆层块结构与地温场，应力场的关系；（４）层流构造的阶段发展与复合叠加；（５）层流构造的深部过程及动力学源，特别强调指出应当区大分陆隆     

阴山山链隆起机制及有关问题探讨

阴山隆起为异常地幔发育区，软流层上凸、岩石圈变薄、幔汁上侵、地幔底辟，垂直运动激烈；阴山隆起又处在南北两大板块夹击挤压构造带上，水平运动强烈。所以，阴山隆起是中新生代垂直运动和水平运动共同作用的结果。随着阴山山链的隆起，在其南缘形成了呼包、临河等地堑式盆地。