机载LiDAR点云的Delaunay三角网快速生成算法

为了提高机载激光点云的Delaunay三角网生成效率及稳定性,基于分块算法的思想,改进了点云数据的分块方式,利用点云的凸包及重心点进行数据分块,并结合子块中激光点个数阈值进行三角形子块的细分,从而避免了传统子块合并过程中复杂的相邻三角形搜索及优化处理,仅需简单的一步优化即可完成相邻子块的合并,大大提高了算法的效率。经实验证明,该算法简单、高效且稳定性好,尤其对于大数据量的机载LiDAR点云Delaunay三角网生成具有明显的优势。     

日光温室中加扣小拱棚的温湿度效应

利用2013年1-2月河北省清河县日光温室中加扣小拱棚后温湿度观测资料和气象站观测资料,采用数理统计法,对不同天气条件下小拱棚温湿度变化特征和温湿度效应进行分析。结果表明：在晴天、少云-多云天气条件下小拱棚内日最高气温分别达30.0 ℃和25.0 ℃以上,且分别比小拱棚外高1.3-6.6 ℃和1.0-4.5 ℃;在晴天、少云-多云天气条件下小拱棚内日最低气温分别为4.0-11.0 ℃和6.0-14.0 ℃,比小拱棚外高0.0-1.5 ℃。小拱棚内日最小空气相对湿度为50%左右,比小拱棚外高2%-11%,日最大空气相对湿度与小拱棚外持平或略高;小拱棚内0.0 m气温和空气相对湿度日变化幅度均小于小拱棚内0.5 m。连续寡照天气时,小拱棚内气温为5.0-15.0 ℃,空气相对湿度全天为85%以上,温度、湿度变化幅度小且与小拱棚外接近或略高。总体来讲,日光温室加扣小拱棚在晴天或少云-多云天气时具有较好的增温保湿效果,但在寡照天气时增温效果不明显。温室中小拱棚内和小拱棚外温度差、湿度差在白天尤其中午前后较大,而在夜间内外相差较小或无差异。在管理上,应注意预防晴天中午前后小拱棚内温度过高引起的灼伤和寡照天气时低温高湿引起的冻害和病害。     

旧石器时代至商周时期贵州遗址空间分布及其自然环境背景(英文)

This study presents an analysis of the spatial-temporal distribution of 230 archaeological sites in Guizhou Province, Southwest China for three selected time periods from the Paleolithic Age to the Shang-Zhou Dynasties. The relationship between archaeological sites distribution and environmental changes is also discussed based on paleo-environmental proxies of δ18O and δ13C recorded in stalagmites from Southwest China. The results show that: in the Paleolithic Age(260–10 ka BP), archaeological sites were concentrated in the central, northwestern and southwestern parts of Guizhou, where the high-altitudinal karst landforms with many natural caves suitable for human habitation are developed. In the Neolithic Age(10–3.6 ka BP), most of human settlements were concentrated in the central, northwestern and southwestern parts, while, a fewer sites were found on river terraces in the southern and eastern parts, and the intermontane basins in the central and western Guizhou. During the Shang-Zhou Dynasties(3.6–2.2 ka BP), the sites were mainly distributed in the intermontane basins and on river terraces, which were suitable for primitive aerial farming. The analysis of paleo-environmental proxies of δ18O and δ13C since 260 ka BP suggested that climate fluctuations had little impact on human settlements in this study area. The distinct physical environment, especially the spatial patterns of karst landforms and arable land played an important role in the archaeological sites distribution of Guizhou.     

全新世浙江地区气候变化对史前文化的影响(英文)

The temporal-spatial distribution features of prehistoric cultures since the Holocene in Zhejiang region were comparatively analyzed based on GIS spatial analysis. Results show that the prehistoric cultures expanded gradually in this region before 4000 cal. a BP. The notable expansions occurred twice, one in the Majiabang-Hemudu cultural period, the other in the Liangzhu cultural period. Meanwhile, the prehistoric cultures were disseminated from west to east coast along river valleys. After 4000 cal. a BP, as represented by the Maqiao Culture, the distributed area of each prehistoric culture contracted. This is obviously due to the termination of spreading trends to east coast, which was simultaneously accompanied by two different modes of production and economic transitions in the north and south Zhejiang region respectively. The distribution of prehistoric cultures was closely related with Holocene sea-level fluctuations, especially on the banks of Hangzhou Bay, where the distribution changes of prehistoric cultural sites were greatly affected by sea-level changes, with the closest relationships between them. After 7000 cal. a BP, the process of lowered sea-level and regression-epeirogenesis provided wider terrestrial living spaces for prehistoric inhabitants. Based on the comparative analyses of the changes of prehistoric cultures and the environmental evolution information recorded in the Qianmutian subalpine peat of Mt. Tianmu and muddy area on the inner shelf of the East China Sea, it is indicated that the changes of prehistoric cultures were synchronized with environmental changes in Zhejiang region. Before 4000 cal. a BP, the eastward expansion of prehistoric cultures in Zhejiang occurred under the background of the Holocene Optimum, and was the expansion and extension under the joint influences of agricultural civilization and maritime civilization. However, after 4000 cal. a BP, the geographical contraction of prehistoric cultures in Zhejiang occurred under the back-ground of dry-cold climate trend and deterioration of coastal marine environment. It is evidenced from the above fact that the development, expansion and contraction of prehistoric cultures are positively correlated to environmental change. The change of the climatic environment is just the underlying reason for these changes and transitions of production modes and economic forms. Therefore, the climatic environment is the dominant factor of prehistoric culture vicissitudes in Zhejiang region, which has exerted great influence on distribution, dissemination, expansion and transmutation of the culture.     

内蒙古牙克石哈拉沟银金矿地质特征

内蒙古牙克石哈拉沟银金矿,位于西伯利亚板块东南古生代陆缘增生带边缘,一系列规模相对较小的中—酸性岩体侵入中生代地层中,形成基本上平行排列的细脉侵染型银金矿床。矿（化）体呈北西西走向,品位低,规模较大,受断裂和岩体共同控制。     

海洋仪器装备测试平台水动力分析及波浪载荷预报

文中介绍了SESAM软件的理论基础和分析流程,并基于三维势流理论应用SESAM软件分析海洋仪器装备测试平台的水动力性能。同时,基于设计波方法进行了波浪载荷预报,为目标海洋仪器装备测试平台的结构设计提供了重要的参考。     

吐哈盆地台北凹陷水西沟群致密砂岩储层特征及影响因素分析

吐哈盆地台北凹陷水西沟群碎屑岩储层获得了高产气流,但由于储层物性较差,岩性致密,针对该储层的储集空间特征及其影响因素的研究分析对水西沟群致密砂岩层段取心的35口井,共385.2m的岩心进行样品采集,共采集样品350余块,制作铸体薄片344块,应用显微镜进行样品的微观组成特征分析;同时应用扫描电子显微镜、阴极发光仪和激光共聚焦显微镜对50余块样品深入研究。研究结果表明水西沟群储层以分选中等,磨圆较差的岩屑砂岩为主;储层压实作用强,粒间孔基本消失,主要的显孔类型为粒内溶蚀微孔,其次是基质晶间微孔和微缝,这三类微型储集空间组成了油气的主要储集空间。通过对砂岩成分组成、成岩环境,成岩作用的研究,认为吐哈盆地台北凹陷水西沟群砂岩储层早期快速压实致密化,后期在微溶蚀和压碎作用共同影响下形成了有效的"三微储集空间"。     

潮流能发电装置测试平台结构设计浅析

目前我国已研制出潮流能发电装置,实海况试验是潮流能发电装置从工程样机走向规模产业化应用的关键环节,为此迫切需要建设发电装置试验测试平台以试验测试发电装置发电效率。文章就潮流能发电装置试验测试平台结构设计做进一步研究,以期为今后该类平台设计提供有益的参考。     

混凝土构件缺陷超声无损检测的研究

对混凝土构件进行超声无损检测,超声波的振幅参数对混凝土构件中的缺陷（裂缝）最敏感,在耦合良好和测试条件基本一致时,振幅值的大幅衰减可作为判断混凝土构件存在缺陷的主要依据。超声波的速度参数对微小裂隙不敏感,缺陷较大会引起速度值的显著下降;频率参数用于检测混凝土构件缺陷不够敏感;对混凝土构件缺陷进行超声检测,速度变化和频率变化只能作为参考因素。超声波通过裂缝与未过裂缝,波形存在明显差异,通过裂缝后,有时会出现很大周期的波列,可作为判断缺陷的重要依据。综合分析超声波运动学和动力学各参数的变化,能够提高检测的准确性。     

基于高空间分辨率遥感影像的水深反演有效性评估

卫星遥感反演水深（Satellite Derived Bathymetry, SDB）是获取浅海水深信息的有效手段。然而,其有效范围只限于光学浅水区域,在深水区域呈现“伪浅海”的失真现象。因此,如何准确识别SDB数据的有效范围对其广泛应用至关重要。本文基于高空间分辨率多光谱卫星影像,在深入分析深/浅水辐射亮度统计分布特征差异的基础上,提出一种数据驱动的水深反演有效性评价方法。该方法以卫星影像辐亮度信息的局域标准差作为特征,基于K-S检验方法对光学深水区域统计特征进行模型优选,并使用假设检验方法对深水无效区域对应的SDB进行识别。甘泉岛水域实验结果表明,该方法通过统计分布划分光学浅水与深水区域边界,可以有效识别光学深水区域产生的无效水深反演数据。在剔除无效区域数据后,光学浅水有效区域内水深反演平均绝对误差（MAE）为1.01,均方根误差（RMSE）为1.52。实验结果表明,本文提出的方法可准确识别SDB结果的有效区域,进而为浅海地形解译提供方法支撑。