Geology of an active hot spot: Teahitia-Mehetia region in the South Central Pacific

The Teahitia-Mehetia hot spot region located in the southeastern extension of the Society Islands chain, near 18° S–148° W consists of several active volcanoes. The distribution of recent volcanic activity correlates with seismic epicenters, and covers an area of more than 1000 km². Intermittent volcanic activity has given rise to large (>1000 m high) and small (<500 m high) edifices composed of various types of flows. Several recent volcanic events have produced a suite of alkalic rocks ranging from ankaramites, through alkali basalts to trachy-phonolites. The presence of altered MORB-like tholeiites on one small seamount suggests that a different mantle source material was involved in forming some of the crust in this hot spot region.     

螺旋浆导管“吸气装置”的减振效果测试与分析

笔者在装有导管防蚀装置的拖网渔船上，进行了实船减振、降噪测试，本文提供了有关充气减振的实船测试结果，并做了一定的理论分析，提出了螺旋桨吸气装置是改善渔船尾部振动和噪声的简便、经济、多效能的好方法。     

基于活力特征分析的城市安置社区公共空间研究——以苏州城区6个安置社区为例

由“散居”到“集居”,安置社区面临社会关系重建的巨大压力。基于公共空间活力内涵,采用AHP-模糊综合评价法,构建了城市安置社区公共空间活力评价模型,以苏州市6个安置社区为例,对3种安置模式的社区公共空间活力特征进行定量评价和比较。发现：① 不同安置模式的社区公共空间活力存在明显差异。尽管异地安置社区的公共空间的设施完备、类型多样,但是其公共空间的社会活力度最低。对于公共空间活力提升,社区公共空间背后的社会属性比其物质属性更为重要。②公共空间因子活力度与关注度存在不匹配现象。基于“社会-空间”辩证互动逻辑,提出安置社区公共空间活力营造策略： 对于今后安置社区,适宜“村内小集居+跨村大聚居”的安置模式,通过最大程度维系原有“熟人社区”群体的社会边界,提升公共空间活力,减轻社区社会关系重建的压力;对于现有安置社区,可根据公共空间因子活力度和关注度的匹配关系,划分公共空间改造的优先级,采用差别化的改造策略,提升公共空间活力及其改造资金的使用效率。     

PROGNOSIS OF AGGRADATION IN THE LOWER YELLOW RIVER BY HISTORIC ANALYSIS OF THE MORPHOLOGY OF ITS ABANDONED ANCIENT CHANNEL

1. INTROOUCnONFor a long time, the Lower Yellow River has been aggtading. As a result, the river bed becomesmuch higher than the adjacent land beyond the levees and poses a threat to the safety of the GreatNorthern Plain of China. Since the founding of the New China, great success has been achieved insafeguarding the levee for forty years. The trend of aggravation in lower reaches however is still Soingon and is at a rate even higher than before. That makes the flood control on the LO…     

SIMULATION OF STRONG GROUND MOTION IN AKETAO M6.7 EARTHQUAKE USING THEORETICAL GREEN'S FUNCTION

Aketao M6.7 earthquake on November 25, 2016 occurred in Aketao Country, Kizilsu Kirghiz Autonomous Prefecture, Xinjiang Autonomous Region. In this paper, according to the focal mechanism solution, the geometrical parameters of the fault are used as input to simulate the acceleration records of the surrounding area of Aketao M6.7 earthquake on November 25, 2016 with the QSGRN/QSCMP program. The peak ground acceleration distribution is plotted by extracted peak ground accelerations and site condition correction. Comparison is carried out between the observed waveforms and the simulated waveforms in the time domain and the frequency domain of two strong motion stations. It is verified that the amplitudes of simulated and observed data are equal in magnitude, their calculated residuals are smaller in low frequency range and the spectral characteristics of simulated and observed data are consistent. Furthermore, the simulated peak ground acceleration corresponding to the coordinates of the actual survey points is extracted and compared with the survey spot intensity, and both have good correspondence. This paper attempts to provide a method for rapid output of peak ground acceleration distribution after an earthquake, so as to provide a method for estimating the seismic impact field in areas where the monitoring station is scarce, the topography is complex or it is difficult to implement the rapid earthquake disaster investigation. And it also provides supporting information for rapid assessment of earthquake disaster and emergency decision-making.     

矿脉控制点投影位置计算方法

矿脉控制点投影到工直纵投影图上的位置,是过矿脉控制点与垂直纵投影面相互垂直的直线和垂直纵投影面的交点。据此建立了求垂直纵投影面、与垂直纵投影面垂直的垂面、过矿脉控制点的水平面这３个平面的交点坐标为矿脉控制点的纵投影点坐标的数学模型,给出了计算方法。     

麦哲伦海山链漂移史及可能的来源

麦哲伦海山链主要由十多座相对独立的平顶海山组成,呈北西向展布于太平洋海山密集区。结合前人对麦哲伦海山链形成和漂移的认识,从板块运动和几何学角度出发采用backtracking和hot-spotting海山追踪方法对该区海山的起源与形成进行了研究,结果表明,麦哲伦海山链是多热点成因的板内火山和板块构造运动共同作用的产物,最初于白垩纪期间由法属玻利尼西亚热点群西侧呈北北西向排列的热点活动产生,继而受到板块运动与区内近南北向和北北东向两组断裂及其热活化等的改造作用,最后形成了现今看到的平顶海山。     

瞬变电磁法在矿产勘查中的应用研究

通过对两个铜多金属矿区4条剖面、一个铅锌金属矿区2条剖面、一个热水矿区2条剖面进行TEM法试验,采用中心回线装置,通过10、20、40、80、100m等不同的发射边框,分别以对数间隔窗口采样和算术等间隔窗口采样进行试验,试验结果说明:在中浅层矿产勘查中,采用瞬变电磁法算术等间距采样 "小框" 较密点距的方法,比传统的瞬变电磁法大边框对数采样间隔方法具有横向分辨率高、轻便灵活的特点,并且也能实现较大的测深。     

几种激光光斑中心检测方法的比较

激光光斑位置的准确确定是决定测量系统精度高低的关键因素,所以激光光斑中心的定位就显得尤为重要。通过对模拟光斑图像进行计算,对常用的几种方法进行了比较并得出了结论。     

嵌入式位图格式与专色印刷技术在“哈同高等级公路沿线详图”中的应用

普通的交通旅游地图册只能满足读者的行车指南要求。那么既能满足读者行车的要求又能满足有关部门维护与勘察要求的图册就不多见了。考虑到有关部门的特殊使用需求与用途,编辑设计了这本采用不规则折页方式的＂沿线详图＂。