Investigation of unrestrained cylinders rolling in steady uniform flows

The goal of this study is to understand the movement of unexploded ordnance that may become unburied and forced by currents. Symmetrical, smooth, finite-length, unrestrained cylinders were studied in steady, uniform flows over a range of Reynolds numbers in a smooth-bottomed, horizontal flume. The study uses PIV tracking methods in the laboratory to identify the movement of ordnance simulated by unrestrained cylinders. The PIV is supported with a numerical analysis using a RANS flow solver. The simulations showed that at low Reynolds numbers the cylinders should roll at speeds near 70% of the free-stream flow.     

地学高层次人才培养，从入门课程《普通地质学》开始

充分发挥专业课程的多维度育人功能是打通基础学科高层次人才培养的关键一环。作为地质学及其相关专业的第一门专业入门课程,《普通地质学》课程主要教授学生地球科学的基本知识、基本技能和基本地质思维等专业知识,同时培养学生的专业兴趣。面对新时代高层次地学人才培养的要求,需要深入挖掘该课程的思政元素,实现教学理念从单纯的传授基础知识、激发专业兴趣到科学素养和人文素养拓展,开启《普通地质学》课程服务地学高层次人才培养的大门。充分利用“将今论古”思想和动力地质作用这两个课程核心内容,培养学生的开拓创新精神和跨学科能力,提升学生的科学素养。同时,依托地质过程的复杂性和庞大的地质时空观等课程核心内容,培养学生的工匠精神、大格局观和发展观,提升人文素养。     

Microwave Millisecond Spike Emission in the Solar Flare of 1991 May 16

Properties, including the time duration, polarization, quasi-periodical oscillations and so on, of the microwave spike emissions observed at 2.5 GHz and 2.6 GHz during the solar flare of 1991 May 16 are analyzed statistically. The left-handed and right-handed circular polarizations of the spike emissions at 2.5, 2.6 and 3.1 GHz are reported in detail. At these 3 frequencies, most of the spikes are superposed on both the rising (and maximum) and the descending phase of the burst. It is noteworthy that spikes also appeared superposed on the small bursts that appeared after the main burst. The spike emission lasted 17 minutes. Polarization reversals on different timescales appearing in the spike emissions at 2.5 and 2.6 GHZ are described. Our statistical analysis indicates that the polarization reversals at 2.5 and 2.6 GHz differ in characters on average, the polarization reversal at 2.5 GHz is earlier than that of 2.6 GHz by about 1.5 minutes, and polarization reversal of the spike emission is more frequent at 2.5 GHZ.     

两次西南低涡造成广西暴雨差异的对比分析

利用ECMWF 2.5°×2.5°客观分析资料和MICAPS常规资料,对2008年6月12日和16日两次西南低涡影响,造成广西暴雨范围和强度明显差异的成因进行了对比分析,结果表明:(1)"6.12"过程西南低涡深厚,其发展过程中始终伴随着强盛的西南低空急流;而"6.16"过程西南低涡较浅薄,其发展过程中无西南低空急流的配合;(2)"6.12"过程低涡发展强盛,涡旋度大,正涡度值达200 hPa高度,上升运动强烈;而"6.16"过程低涡发展较弱,涡旋度小,正涡度值只到500 hPa高度,上升运动相对较小;(3)"6.12"过程水汽来源于孟加拉湾和南海,水汽辐合强;而"6.16"过程水汽仅来源于孟加拉湾,水汽辐合较弱;(4)两次西南低涡影响,对流层上下之间的风垂直切变小,有利于中尺度对流云团的发生发展.     

GPON光纤技术在山东地震信息网络中的应用

简要介绍了山东省地震行业信息系统的组成和功能,以及新建系统的项目背景、建设需求。介绍了光纤通信的发展历程,Epon和Gpon技术的基本原理及优、缺点和采用光纤组网的技术优势,以及结合山东省地震局信息系统实际和今后业务的发展规划。同时考虑了如何设计、技术思路和实施方案,以使该设计思路和方案最大程度的发挥优势。     

强震条件下双面坡变形破坏机理的振动台物理模拟试验研究

5.12汶川地震引发了数以万计的崩塌、滑坡、泥石流等地质灾害。为了研究双面坡在强震条件下的动力响应规律,本文在大量野外调查的基础上,采用振动台物理模拟试验手段,设计完成了四类11个模型试验,从改变模型的坡度和坡顶宽度、软岩硬岩结合、阶梯状坡形等角度,较系统地研究了双面坡在强震作用下的响应规律。试验结果显示:强震条件下地震水平惯性力是导致边坡破坏的主要原因;在地震情况下边坡变形破坏表现出明显的初动破坏效应;振动过程中双坡具有明显的共剪效应,坡面为阶梯状时其共剪效应更明显;坡体结构为上软下硬时下部硬岩对振动具有一定的放大效应,上硬下软时坡体易整体偏移产生变形破坏。试验结论与实际情况基本符合。     

Blazar天体的辐射特性研究

收集了47个Blazar天体的短时标光变资料,估算了中心天体质量和不同波段辐射区域,并对估算结果作了统计分析,发现Blazar天体中心黑洞质量在10~7M_☉到10~(10)M_☉之间,BL Lac天体与平谱射电类星体中心黑洞质量有很大差异,平谱射电类星体中心黑洞质量大于BL Lac天体中心黑洞质量;红外波段和γ射线波段辐射区域大小相似.同时,利用收集到Blazar天体的热光度分析了Blazar天体热光度与短时标光变之间的关系,证实了射电选BL Lac(RBL)天体和平谱射电类星体(FSRQs)的辐射是强成束的,但相对论聚柬效应对X射线选BL Lac(XBL)天体的辐射影响较小.     

从地壳运动角度分析大陆强震机理的一种物理方法

为了从地壳运动角度利用重复大地测量数据分析大陆强震机理,提出了利用反映地壳内部密度变化或时变的物理量来分析强震发生的密度变化机理的一种物理方法(1)介绍了地球内部密度时变的一般理论和单层密度时变理论,提出了分步迭代算法;(2)简要分析了断层位错引起的单层密度变化效应;(3)分析了1996年丽江7级地震前震区南部地壳密度时变(变化)的特征;(4)初步探讨了强震孕育过程中可能的地壳内部密度时变(变化)前兆模式或发震机制.     

基于雷达卫星图像的黄淮海平原城镇体系空间结构研究

基于雷达卫星ScanSAR遥感图像分析 ,根据中心地理论 ,对黄淮海平原不同地貌、水文等要素影响下的城镇体系空间结构进行研究。结果表明 :1)利用雷达遥感对结构信息的灵敏反应和雷达卫星ScanSAR合适分辨率 ,在图像上直接显示出建成区的分布和范围 ,直观反映出城镇相对等级 ,这也表明雷达遥感在城市地理研究中的应用潜力 ;2 )黄淮海平原城镇空间结构深受自然条件特别是地貌尤其是水文 (河流、古河道、湖泊 )的影响 ,城镇体系可划分为 5种类型区 ;3)发展了河流影响下的中心地体系由六边形向五边形或四边形演化的构建模型 ;4)无论六边形还是五边形的中心地体系 ,本区体现了理论上对中心地间的距离构建法则与实际情况的良好关系 ,实证了克氏的中心地理论在黄淮海平原重要农产区的某种存在。     

Preliminary Research on Relation Between Field and Source in Earthquake Preparation

The "field" and "source" are two important branches in seismology and earthquake research.In this paper,we use a computer model to study the relation between the field and the source in earthquake activity.In our modeling,a network of nonlinear elements is used to simulate seismic activity of seismic zones in a seismotectonic block.Constant strain rate is enforced on the boundary of the model,cyclic seismic activity,quasi-periodic variation of stress field intensity,and strain energy are observed with high and low fluctuations.There is a main seismicity area in seismic cycles,and the main seismicity area shows the spatial migration during different seismic cycles.If the precursory area is related to high element stress,it is found that the development of precursors in our model is quite complicated.No certain relation between the precursors and earthquakes has been discovered.Anomalies show different characteristics in the seismic quiet period and active period.All of the seismic zones in the system hav