某Cr(Ⅵ)污染场地修复的PRB反应材料及结构设计研究

渗透反应格栅(permeable reactive barrier,PRB)在国外被广泛应用于场地尺度的地下水污染修复,因其无须外源动力、不占地面空间、运行成本低等优势在国内受到广泛关注。不同场地水文地质条件、污染物类型、污染羽分布具有差异性,前期场地调查、反应材料的筛选、反应墙尺寸结构的设计对于PRB的有效运行至关重要。本文以PRB修复河南某Cr(Ⅵ)污染场地为例,详细阐述场地调查、材料筛选、材料反应参数确定、PRB结构优化等方面的研究过程及成果,可为后续PRB修复技术的应用提供参考。研究结果表明:PRB修复技术适用于该场地,铸铁与活性炭混合材料为最佳修复材料;反应门长40 m(反应材料厚2 m,上下游分别为2 m厚砾石层),东西两侧隔水墙长为60 m的U型漏斗-门系统型PRB,可有效捕获并修复污染羽,工程成本远低于连续反应墙式PRB,为该场地修复最优PRB结构类型。     

滑坡对降雨响应的多指标监测及综合预警探析:以赣南罗坳滑坡为例

降雨量和位移是当前降雨型滑坡监测预警最常用的指标。然而,降雨量和位移监测结果只能反映降雨作用下滑坡的变形情况,不能揭示滑坡内在物理力学性状对降雨的响应。因此,除降雨量和位移监测之外,建立包括体积含水率、基质吸力等反映滑坡动态演化过程的关键指标监测体系必将成为今后更真实地把握滑坡内在演化趋势、更准确地建立滑坡综合预警判据的最有效手段。笔者对赣南地区典型降雨型滑坡进行了多指标监测及综合预警示范研究。结果表明:(1)在降雨条件下滑坡土体内部体积含水率、基质吸力和温度等多指标均产生有规律的动态响应;(2)随着降雨的持续,滑体体积含水率与基质吸力的变化均具有显著的滞后现象;(3)体积含水率和基质吸力变化速率与滑体位移具有显著的正相关性;(4)滑体温度分布变化规律受大气温度和体积含水率的共同影响。以实测数据的滑坡稳定性分析为基准,在考虑实际降雨入渗深度与滑坡稳定性的关联度上,建立了包括日降雨量、体积含水率增加速率、基质吸力减小速率以及位移速度多元指标预警方法体系,提出了基于关键指标综合预警体系及确定方法,旨在为降雨滑坡准确预警提供新模式。     

中亚造山带南缘中—新元古代地壳的揭示——来自北山—阿拉善北部钻遇碱性花岗岩的年代学和Hf同位素示踪研究

前寒武纪微陆块是北山—阿拉善北部增生造山带的重要组分,旱山、雅干和珠斯楞—杭乌拉地区的前寒武纪基底是否存在学界尚存争议.居延海介于北山造山带北部和阿拉善地块北缘的构造衔接部位,受限于巴丹吉林沙漠覆盖,岩石露头极少,我们通过钻井工程,钻遇一套晚石炭世碱性花岗岩,锆石U-Pb年龄和Hf同位素特征揭示,该花岗质岩浆锆石结晶年龄为(312±1)Ma(MSDW=0.46,n=18)和(315±2)Ma(MSWD=0.93,n=15),具有正的εHf(t)值,介于+0.8～+4.4之间,平均值为+2.2,对应二阶段模式年龄TDM2为1048～1267 Ma,平均值为1183 Ma,具有古老地壳的源区属性.通过与旱山构造带、雀儿山构造带、雅干构造带和珠斯楞—杭乌拉构造带的晚石炭世花岗质岩浆对比分析,结合旱山构造带、雅干构造带和珠斯楞—杭乌拉构造带0.9 Ga花岗质岩石的出露以及区域上的重磁资料解译,我们认为旱山、雅干和珠斯楞—杭乌拉构造带存在中—新元古代地壳,且可开展进一步的衔接关系研究.     

巴音戈壁盆地塔木素铀矿床含矿砂岩成岩作用类型、演化序列及其对铀成矿的约束

勘查和研究发现部分砂岩型铀矿床中不仅有表生氧化流体作用还存在深部流体的参与,这类砂岩型铀矿床蚀变类型多样且成因复杂.塔木素砂岩型铀矿表生流体和深部流体活动都很明显,砂岩普遍固结且后生蚀变类型独特,因此,恢复成岩成矿事件及其演化过程,对揭示铀沉淀富集机理至关重要.本文通过镜下鉴定、电子探针、扫描电镜分析等,系统研究了塔木素矿床含矿砂岩成岩作用特征与后生蚀变矿物生成序列,重塑了成岩成矿事件的演化过程.研究结果显示,塔木素矿床砂岩中压实作用较弱而胶结作用很强,重结晶作用普遍,是造成目的层致密的主要原因,赤铁矿、褐铁矿化、碳酸盐化、石膏化是该地区主要的胶结类型.将该地区的成岩演化划分为沉积-早成岩阶段、早期氧化流体作用阶段、热流体改造阶段和晚期氧化流体弱改造阶段.成岩环境由弱碱性向酸性环境转变的过程中的氧化还原过渡部位是造成铀沉淀的关键,大规模的氧化作用是矿床形成的基础,后期热流体活动对早期形成的低品位铀矿石进行叠加改造,是成矿的关键环节.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

THE TEMPORAL AND SPATIAL DISTRIBUTION OF SEA SURFACE WIND ALONG THE COAST OF GUANGDONG PROVINCE IN CHINA

Temporal and spatial distribution characteristics of sea surface wind in Guangdong''s coastal areas were analyzed with data from four offshore observational stations between 2012 and 2015. The results are shown as follows: (1) The probability distribution of wind speed was basically consistent with Gaussian distribution characteristics; winds of Beaufort force 6 or higher were observed mainly in far offshore stations from October to March. (2) The probability distribution of wind direction was represented well by Weibull distribution. The deviation of wind direction of far station was relatively small for it was mainly controlled by monsoon over the South China Sea, while the near offshore station had a relatively large diurnal variation because of the influence of local synoptic systems such as sea-land breeze. (3) There were significant seasonal differences in wind speed and direction observed by different offshore observational stations. In strong wind seasons, the deviation of wind direction was relatively small while the deviation of wind speed was relatively large, and vice versa. In contrast with Class I station, the other three stations exhibited approximately normal distribution of wind direction and wind speed deviations. (4) Wind direction diurnal variation was moderate in windy periods, while it was obvious in relatively lower speed conditions. The deviation of wind speed in windy periods was generally greater because it was influenced by mesoscale weather systems for 10-20 h, and the influence was complicated, resulting in greater local differences in wind speed.     

GRAPES全球集合预报系统模式扰动随机动能补偿方案初步探究

为了体现次网格尺度能量升尺度转换过程中存在的不确定性, 文中将随机动能补偿(Stochastic Kinetic Energy Backscatter, SKEB)方案应用于GRAPES(Global/Regional Assimilation and Prediction System)全球集合预报系统(GRAPES-GEPS), 以更好地表征模式误差并且增大集合离散度。使用的SKEB方案基于具有一定时、空相关特征的随机型以及由数值扩散导致的局地动能耗散率来构造随机流函数强迫。并根据流函数与水平风速旋转分量的关系, 将SKEB方案中的流函数强迫转化为适用于GRAPES全球模式的水平风速扰动。结果表明, SKEB方案的使用一方面能够提高GRAPES对大气动能谱的模拟能力; 另一方面能够改善GRAPES-GEPS的集合离散度与集合平均误差的关系, 增加了集合离散度, 并在一定程度上减小了集合平均误差, 尤其是在热带地区这种改进更为显著。而且该方案使得热带地区连续分级概率评分(CRPS评分)显著减小。就降水预报而言, 从Brier评分与相对作用特征面积(AROC, Area under the Relative Operating Characteristics)的结果来看, SKEB方案有助于改善中国地区小雨[0.1 mm, 10 mm)、中雨[10 mm, 25 mm)与大雨[25 mm, 50 mm)量级降水的概率预报技巧, 而对暴雨[50 mm, ∞)量级降水预报技巧影响很小(24 h降水量)。总体上, 模式扰动随机动能补偿方案提高了GRAPES-GEPS的概率预报技巧。      

Matlab与高级编程语言在科学计算中的联合运用

在数字地震观测、地震预报及地震工程研究中,Matlab作为一套功能强大的科学计算及数学分析软件,得到广泛的应用.本文介绍如何将Matlab高效的数值计算和分析能力与高级编程语言结合的方法.     

如何提高磁照图数字化的精度

CBMD是一款针对CB-3模拟磁照图进行数字化处理的软件,利用专业图像处理技术,对模拟磁照图进行数字化,由于模拟仪器调试及存放因素造成了图纸状况不尽相同,使用者在数字化处理过程中,根据不同的图,纸采用相应的方法进行处理,才能保证数字化结果精确度.本文就主要的几种影响处理精度的情况展开讨论,并提出具体的解决方法.     

胶东乳山金矿蚀变岩中绢云母40Ar/39Ar年龄及其对金成矿事件的制约

胶东乳山金矿是我国单脉金储量最大的矿床,金的成矿具有多期多阶段的特点。为了研究早期矿化的时代,利用绢云母40Ar/39Ar法测定了乳山金矿含矿脉体旁围岩蚀变带中的绢英岩年龄。结果表明,围岩花岗岩的强烈绢英岩化蚀变年龄为129 Ma,比金发生大规模沉淀的成矿时间早约10 Ma,表明乳山金矿是多期热液成矿事件的产物,但这一事件也发生于120±10 Ma,从而证明乳山金矿与胶东其他地区金矿一样都是在中生代构造机制转折、岩石圈强烈减薄的构造背景下集中成矿的,这为进一步认识乳山金矿的成因机制和成矿动力学背景提供了新的证据。