高土石坝振动台模型试验理论、技术与应用

对土石坝振动台模型试验理论和技术进行系统阐述,提出基于原型和模型坝料静、动力特性试验的模型相似设计方法和不同强度地震动递进输入(白噪声微振-设计地震-校核地震-破坏试验)的振动试验方法。基于1g大型振动台和ng超重力离心机振动台设备性能现状,结合高土石坝的结构特点和动力试验相似模拟要求,对土石坝振动台模型试验的优势及局限进行深入讨论。结合已有的工程实践,对土石坝振动台模型试验在工程中的应用进行总结,并以某实际高面板堆石坝为例研究面板坝生命周期内经历多次地震情况下结构动力特性的演化规律。     

伶仃洋第四纪沉积物的铀钍含量和年龄分析

样品采自珠江口伶仃洋海区的５个钻孔。测量了各样品中之Ｕ，Ｔｈ含量、比值及年龄。结果表明，这５个钻孔基底面上沉积之最老年龄距今超过３６０００ａ。     

先期震动对土石坝地震永久变形的影响研究

针对经历了5.12汶川大地震的紫坪铺面板堆石坝工程,进行了坝料的大型动三轴试验,研究了先期振动对坝料残余应变的影响。在此基础上,采用基于3维非线性动力反应的地震永久变形计算方法,进行了紫坪铺面板坝地震永久变形的计算,重点分析了先期震动对坝体地震永久变形的影响。结果表明,如果考虑先期已遭受强震作用影响,大坝的地震残余变形明显减小。     

一种海量遥感影像实时切割与高效调度新方法

针对传统影像组织方法——瓦片金字塔模型实现海量遥感影像调度存在的问题,提出一种瓦片实时切割与高效调度的新方法。在.net平台上使用C#语言开发了基于瓦片实时切割与调度和瓦片金字塔模型两种方法的瓦片服务发布系统,并用实验进行了对比分析。实验结果表明,新方法无需创建瓦片金字塔模型,节省了大量的时间和空间;同时瓦片调度速度有所提高,从而实现了海量遥感影像实时切割与高效调度。     

Spatial distribution,variation and trend of five-day antecedent rainfall in Singapore

ABSTRACT

This paper presents the spatial distribution, variation and trend of 5-day antecedent rainfall in Singapore based on rainfall data from 22 meteorological stations. The effect of climate was analyzed by dividing the study period into three decades i.e. Decade 1: 1982–1991, Decade 2: 1992–2001 and Decade 3: 2002–2011. Kriging interpolation was used for rainfall mapping. The results show that spatial distribution of 5-day antecedent rainfall does not coincide with that of the annual rainfall. The maximum annual rainfall occurred in the northwestern side of Singapore. On the other hand, the maximum 5-day antecedent rainfall occurred in the north and northeastern sides. The results of this study suggest that the climate change has increased the amount of 5-day antecedent rainfall quite significantly, i.e. from 420.5 (1987) to 592.9 mm (2006), thus affecting the vulnerability of the area with respect to rainfall-induced slope failure. The analyses also showed that most of slope failures were located in the north and northeast of Singapore between December and earlier March. More slope failures were observed in Decade 3 as compared to Decades 1 and 2. In other words, the analysis confirmed that 5-day antecedent rainfall had affected the slope stability in Singapore.     

上海地区热量平衡状况的初步分析

利用上海地区1961—1965年的热量平衡资料以及常规的气候资料，分析了该地区热量平衡各分量的年、月、日变化规律，进一步阐明了我国湿润地区在地表热量平衡过程中，潜热占绝对优势的特征。     

Discussion on the tree-based machine learning model in the study of landslide susceptibility

Natural Hazards - This study reported an application of the tree-based models to landslide susceptibility. The landslide inventory and ten conditioning factors were first constructed, based on data...     

桂林茅茅头大岩石笋的铀系年龄测试及其形成速度

<正>前言 开展石笋、钟乳石、石灰华等的地质年龄及其形成速度的研究,对于研究岩溶洞穴的发育史具有重要意义,由于其年龄范围常在几万年至几十万年之间,所以应用铀系测年方法较为合适。在国外,从六十年代末至七十年代初就开展了这方面的研究工作,如Fcrnanca等(1968)论证了~(230)Th/~(234)U比值在洞穴年龄测定方面的潜力;Ngvyen等(1969)研究了以铀系测定石笋年龄的方法;格林·M(1974)等对英国Blanchard Springs洞穴石笋的年龄进行了研究,认为应用~(234)U/~(238)U法最为合适。      

水下激光通讯发射接收系统

报导了可用于水下激光通讯的由８９ｃ５１单片机控制的全双工水下激光通讯系统实验装置。系统能有效的消除水下背景光的影响,并具有３～４个数量级动态范围的自动增益放大能力以更有效地接收水下激光通讯信号。能在水下以较高的数据传输率传递信息,数据传输率可以用软件调整,最大数据传输率为１９．２ｋＢｉｔｓ／ｓ。