华南早古生代陆内造山演化

华南早古生代造山带的构造属性长期缺乏统一的定论,且此次构造事件的形成机制与动力学背景研究较少。本文在前人研究成果的基础上,综合沉积环境、岩浆作用与岩浆来源、构造变形以及变质作用等地质证据,再次审视华南早古生代的构造演化过程。研究表明：1）华南广泛发育泥盆系与下伏前泥盆纪地层之间的角度不整合面,早古生代沉积相自江南区到华夏区呈过渡渐变,无同期火山碎屑岩、含鲍马序列的浊积岩等洋盆相关的记录;2）华南出露大规模弥散型面状分布的S型花岗岩,结晶年龄集中于443～423 Ma,在任何方向均无新老演化趋势,且岩浆主要来自壳源物质的熔融再循环,几乎无幔源物质加入;3）华南早古生代以低绿片岩相变质作用为主,仅陈蔡、龙游等地区零星出露绿片岩相—麻粒岩相变质岩;变质时间与岩浆结晶年龄相近,变质P-T-t轨迹均为近等温降压的顺时针轨迹;4）华南早古生代绝大部分构造线为近S-N与NE方向,变形作用以韧性流变为主,以武夷山瑞金—遂昌为轴呈双向逆冲推覆构造模式。根据以上地质事实,本文推断华南早古生代构造事件属性为陆内造山,即华南板块边缘汇聚碰撞产生的应力,经岩石圈远距离传播至大陆内部的远程响应。     

铬污染对土壤细菌群落结构及其构建机制的影响

重金属铬污染场迁移过程受多种不确定因素影响,其迁移特性和监测过程很难通过实验进行研究。依据地下水流动基本规律和污染物迁移机理,采用COMSOL软件仿真分析静储量铬污染源的迁移特性及其变化规律,通过开展静态土槽物理模型实验,验证数值正演模拟的可靠性和准确性;以迁移模型为监测基础模型,采用中梯剖面和对称四极测深装置,对铬污染场迁移过程进行双频激电法监测数值正演模拟,分析平整、起伏地形和测点方位布置对监测效果的影响。结果表明：在铬污染物迁移过程中,高渗透系数的透水层对重污染区域表现出强烈的吸附效应,同时会在短时间内加剧污染区域的横向扩散;在视幅频率峰值和视电阻率谷值的异常对应关系上剖面探测要优于测深探测;对称四极测深时,在污染场的投影边缘中央设置测点可更有效地提高测量精度;在进行剖面和测深探测时,山谷会造成激电曲线出现“多峰”现象;在凸起山峰两侧山陲设置供电电极,通过视幅频率和视电阻率曲线可综合确定重度污染区域的具体位置。研究成果丰富了双频激电法对重金属土壤污染场监测的理论,为铬污染场实时监测提供理论依据和技术指导,对推动生态环境保护具有积极意义。

     

南极半岛东北部海域表层沉积物稀土元素特征及物源指示意义

通过对南极半岛东北部海域36个表层沉积物样品的稀土元素分析发现:(1)研究区表层沉积物中稀土元素总量(REE)的分布范围为(45.47~183.60)×10-6,平均值为91.36×10-6;稀土元素含量的高低与铝硅酸盐黏土成正比,与生物硅含量成反比;(2)大致以象岛至南极半岛北部的茹安维尔岛为界,研究区西部的布兰斯菲尔德海峡及南设得兰群岛北部岛架-岛坡沉积物稀土含量较低,稀土元素页岩标准化模式与长城站周边土壤/湖泊沉积物、火山岩相一致,表现为重稀土相对富集,铕正异常明显,Sm/Nd分子比值大,推断该区沉积物主要来源于南设德兰群岛中-新生代火山岩分布区与现代火山活动区;(3)研究区东部鲍威尔海盆、南奥克尼群岛岛架和南斯科舍海脊区沉积物稀土元素的页岩标准化配分模式表现为平坦型,轻稀土明显抬升,铕正异常不显著,Sm/Nd分子比值小,稀土元素含量受沉积物中黏土组分含量、硅质生物组分等制约,推断沉积物陆源碎屑主要来源于威德尔海西部和南部,局部受南奥尼克群岛、南斯科舍海脊和南设德兰群岛物质的影响,沉积物的搬运主要受冰筏和海流制约。     

A gravitationally non-degenerate cosmological model with expanding and shearing viscous fluid in general relativity

The object of this paper is to investigate the behaviour of viscosity in a cosmological model, in which the coefficient of shear viscosity is assumed to be proportional to rate of expansion in the model. The behaviour of the model in the absence of shear viscosity is also discussed.     

2,4,6-trinitrotoluene transformation by a tropical marine yeast, Yarrowia lipolytica NCIM 3589

Yarrowia lipolytica NCIM 3589, a tropical marine degrader of hydrocarbons and triglycerides transformed 2,4,6-trinitrotoluene (TNT) very efficiently. Though this yeast could not utilize TNT as the sole carbon or nitrogen source, it was capable of reducing the nitro groups in TNT to aminodinitrotoluene (ADNT). In a complete medium containing glucose and ammonium sulphate as the available carbon and nitrogen sources respectively, the culture was able to completely transform 1 mM (227 ppm) of TNT under such conditions. A dual pathway was found to be functional, one of which resulted in the formation of the hydride-Meisenheimer complex (H(-)TNT) as a transiently accumulating metabolite that was subsequently denitrated to 2,4-dinitrotoluene (2,4-DNT), whereas the other pathway resulted in the formation of amino derivatives. The presence of increasing amounts of reducing equivalents in the form of glucose promoted better growth and the nitroreductases of this yeast to reduce the aromatic ring to 2,4-DNT although, the reduction of the nitro groups to amino groups was the major functional pathway. The ability of this tropical marine yeast to transform TNT into products such as 2,4-DNT which in turn could be metabolized by other microbes has implications in the use of this yeast for bioremediation of TNT polluted marine environments.     

数字地震台电源远程监控系统

以STC89C52单片机为核心,开发基于"十五"网络的地震台站电源远程监控系统,实时的监控台站仪器设备的状态并收取状态参数,实现设备复位操作及故障报警,可以提高地震台网中心仪器运行效率。     

利用HOG-LBP自适应融合特征实现禁令交通标志检测

针对禁令交通标志牌提出了一种基于HOG-LBP自适应融合特征的交通标志检测方法,将标志图片等分为多个不重叠的块,每块内将加权后的HOG和LBP特征进行串行融合作为最终特征,其中每类特征权值由块内梯度幅值决定,融合后的特征采用SVM进行分类器训练,并将训练结果用于交通标志检测。实验结果表明,基于HOG-LBP自适应融合特征的效果优于基于单独HOG、LBP特征和简单HOG-LBP融合特征的效果。     

面向21世纪的煤化工

煤炭是中国的主要能源和资源，但同时也是主要的污染源。从保护环境、合理利用有限的化石资源的角度和中国的具体国情考虑，应该大力开发温和化高效煤的新工艺，使煤炭资源逐步由能源型利用转化为材料型利用，近年来，我们在煤的溶剂萃取，脱硫降灰机理，煤相关模型化合物反应，煤焦油中稠环芳香族化合物的分离精制，功能性高分子单体合成及一氧化碳高效吸附剂的制备等方面做了大量的研究工作，结合这些研究工作，本文介绍了煤化工的     

Snow cover depletion under changed climate with the help of remote sensing and temperature data

Snow cover depletion curve (SDC) is one of the important variables in snow hydrological applications, and these curves are very much required for snowmelt runoff modeling in a snowfed catchment. Remote sensing is an important source of snow cover area which is used for preparation of SDC. Snow cover maps produced by Moderate Resolution Imaging Spectroradiometer (MODIS) satellites are one of the best source of satellite-based snow cover area at a regular interval. Therefore, in this study, snow cover maps have been prepared for the years 2000?C2005 using MODIS data. The study area chosen viz. Beas basin up to Pandoh dam falls in western Himalayan region. For snowmelt runoff modeling, catchment is divided into number of elevation zones and SDC is required for each zone. When sufficient satellite data are not available due to cloud cover or due to some other reasons, then SDC can to be generated using temperature data. Under changed climate conditions also, modified SDC is required. Therefore, to have SDC under such situations, a relationship between snow cover area and cumulative mean temperature has been developed for each zone of the catchment. This procedure of having snow cover maps has two main purposes. First, it could potentially be used to generate snow cover maps when cloud-free satellite data are not available. Second, it can be used to generate snow-covered area in a new climate to see the impact of climate change on snowmelt runoff studies.     

大洋碳循环与气候演变的热带驱动

20世纪气候演变研究的最大突破,在于地球轨道变化驱动冰期旋回的米兰柯维奇理论。然而近年来学术界对热带过程和大气CO2浓度变化的研究进展,暴露了传统的轨道驱动理论存在着对低纬区和碳循环在全球气候系统中作用估计不足的严重缺陷。国家重点基础研究发展计划项目"大洋碳循环与气候演变的热带驱动"拟以南海与西太平洋暖池的深海记录为依据,进行全球性对比和跨越地球圈层的探索,通过观测分析结果与数值模拟的结合、地质记录与现代过程的结合,检验和论证大洋碳储库长周期变化机制的假说,对于不同时间尺度上低纬过程如何通过碳循环在全球气候环境演变中的作用,实现理论上的突破。同时简要介绍了该项目的目的、科学意义、关键科学问题及预期目标等。