测距仪倾斜引起的误差分析与改正     

张升峰  郭福生  李广云 《海洋测绘》2004,24(5):32-34

重点研究积木式全站仪在大垂直角测距中由于测距仪中心与经纬仪中心不一致而引起的测距误差，针对这些误差的来源及特征，制定出相应的修正措施，从而达到提高测距精度的目的。  相似文献   

Wave Loads and Protective Techniques of An On-Shore Wave Power Device     

You Yage YuZhi Associated Professor  Guangzhou Institute of Energy Conversion  Chinese Academy of Sciences  Guangzhou . Professor  Guangzhou Institute of Energy Conversion  Chinese Academy of Sciences  Guangzhou 《中国海洋工程》1995,(4)

In this paper, the extreme wave loads on an on-shore wave power device are investigated. First, boundary element method is applied to solve the three dimensional potential problem based on the small amplitude wave assumption. Then the motion of the Oscillating Water Column (OWC) inside the device and its laods on the device are calculated in time domain. Several protective techniques often applied are simulated by changing the constraint of the upper end of the chamber of the device. Numerical results are used to judge the effectiveness of these techniques. The investigation shows that damping can not effectively restrain the motion of OWC when the period of incident wave is long, which may cause dangerous loads on the structure. The shut chamber can effectively restrain the motion of OWC, but alternatively cause high pressure in the chamber. A Contracting opening with a Taper (CT) can exhaust a great amount of kinetic energy of OWC, and significantly decrease the loads. It is a promising protective tec  相似文献   

半叶马尾藻多糖对辐射损伤小鼠骨髓细胞集落生成的影响   总被引：3，自引：0，他引：3  

孟庆勇  刘志辉  郑辉 《中国海洋大学学报(自然科学版)》2005,35(3):503-506

探讨半叶马尾藻多糖[Sargassum hemiphyllum(Turner)C．Ag．polysaccharides，SHP]对辐射损伤小鼠骨髓细胞集落生成的影响。检测辐射损伤小鼠脾集落生成单位、红细胞集落生成单位、爆裂型红细胞集落生成单位、粒细胞．巨噬细胞集落生成单位、巨核细胞集落生成单位、混合集落生成单位的变化。5Gy7射线照射后小鼠CFU-S，CFU—E，BFU—E和CFU—Mix明显减少，而SHP(20mg／kg-40mg／kg)可以抑制CFU—S，CFU—E，BFU—E和CFU—Mix下降。辐射损伤也可以引起小鼠CFU-GM显著降低，但是，SHP(10mg／kg-40mg／kg)具有拮抗辐射损伤的作用，使CFU-GM增加。单纯照射组小鼠CFU—Meg显著低于正常对照组，SHP(40mg／kg)加照射组小鼠CFU-Meg却显著高于单纯照射组。SHP对辐射损伤小鼠多能干细胞和造血祖细胞具有保护作用。  相似文献   

红树叶片衰老过程中活性氧和保护酶活性的变化   总被引：2，自引：0，他引：2  

张平  谢潮添  杨盛昌 《海洋科学》2004,28(5):37-40

测定了红树植物木榄(Bruguiera gymnorrhiza)和秋茄(Kandelia candel)幼叶、成熟叶和老叶间活性氧和三种细胞保护酶活性的变化。结果表明，在叶片衰老过程中，丙二醛和H2O2含量显著提高，超氧化物自由基产生速率加快，表明红树叶片衰老中膜脂过氧化作用增强，并且与H2O2和超氧化物自由基含量的上升相关。在3种细胞保护酶中，超氧化物歧化酶(SOD)活性逐渐降低，过氧化物酶(POD)活性显著提高，过氧化氢酶(CAT)活性在叶片成熟过程中增高，随着衰老而急剧降低，细胞保护酶酶活的变化直接影响了叶片衰老过程中活性氧代谢的平衡。  相似文献   

阜阳华纺新天地超长空桩成孔施工控制措施          下载免费PDF全文

邢敏 《探矿工程》2018,45(6):89-91

阜阳华纺新天地桩基工程,原计划基坑底面施工调整为地面施工,增加了近14 m的空桩。为此,工程桩施工质量存在桩位、孔底沉渣厚度、钢筋笼位置、砼质量、砼桩顶标高等方面控制的相关问题。本文介绍了其施工情况,其经验可供类似工程借鉴。  相似文献   

浅析“大同睡佛”断块山地貌景观的成因及保护     

崔晓立  陈继福  董秀桃 《四川地质学报》2012,32(3):373-376

地质遗迹是地球发展变化过程中给人类留下的宝贵财富,具有科研价值、学术价值及观赏价值.“大同睡佛”断块山地貌景观与大同云冈石窟遥相呼应,对发展当地的旅游事业有重要意义.根据“大同睡佛”断块山地貌景观区的地质特征探讨了其形成原因,提出了对大同保护措施建议.  相似文献   

浅析四川汶川索桥滑坡稳定性及治理措施     

阳建新  李发菊  陈田华 《华北地质》2012,(3):210-213

根据工程地质测绘及勘探成果资料,在对四川汶川县索桥滑坡产生的成因机理和破坏模式进行分析判断的基础上,对两个潜在滑移面在不同的工况下的稳定性进行了分析评价,确定岩土交界面为最危险滑面.在此前提下对边坡发展趋势及激发诱因进行科学预测,认为在暴雨或余震等诱发下边坡极有可能失稳,并有针对性的制定了应急防治与永久根治的综合治理方案.  相似文献   

Multiscale approach to geo‐composite cellular structures subjected to rock impacts     

François Nicot  Philippe Gotteland  David Bertrand  Stéphane Lambert 《国际地质力学数值与分析法杂志》2007,31(13):1477-1515

Geo‐composite cellular structures are an efficient technological solution for various applications in civil engineering. This type of structure is particularly well adapted to resisting rockfalls and can act as a defensive structure. However, the design of such structures is for the most part empirically based; this lack of research‐based design stagnates optimization and advanced development. In this paper, the mechanical behaviour of a geo‐composite cellular structure is investigated using a multi‐scale approach, from the individual cell made up of an assembly of rocky particles contained in a wire netting cage to the entire structure composed of a regular array of cells. Based on discrete modelling of both the cell and structure scales, a computational tool has been developed for design purposes. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

高光谱遥感的物质组分和物质成分反演的应用分析     

王润生 《地球信息科学学报》2009,11(3):261-267

高光谱遥感的最大特点是可以提取和重建像元光谱,从而依据光谱特征直接识别地物类型、地物组成,乃至地物的成分,反演地物的物理、化学参量。本文阐述了高光谱的光谱识别方法所能探测的岩石、土壤、植被和人工建筑物的物质组分或成分;另外,与多光谱相比较的角度,讨论了高光谱图像地物特征识别和物质成分反演等技术方法的应用。  相似文献   

Assessment of Man-made and Natural Hazards in the Surroundings of Hydropower Projects under Construction in the Beas Valley of Northwestern Himalaya     

Sanjeev Sharma Jagdish C. Kuniyal J. C. Sharma 《山地科学学报》2007,4(3):221-236

Mountain ecosystem,on the earth,has plenty of natural resources. In Himachal Pradesh all the rivers are snowfed and therefore rich in water resources. These resources have been supporting enough for the generation of electricity through introducing hydropower projects since the last decade. However,every developmental activity has its own negative impacts on the surrounding environment. Due to the fragile nature of topography and delicacy of ecology of the Himalaya,it results in lot of disturbances because of high degree of human interferences like construction of major hydropower projects. The increased extent of geological hazards,such as landslides,rock fall and soil erosion,have mainly due to alike developmental interventions in the natural ecosystem. So understanding and analysing such impacts of the hydropower projects have mainly been on the environment in various forms but natural hazards have been frequent ones. The present study,therefore,focuses mainly on the Parbati Stage Ⅱ (800 MW) and the Parbati Stage Ⅲ (520 MW) hydropower projects; both of which fall within the Kullu district of Himachal Pradesh. Based on the perception survey of the local communities,the existing land use pattern,status of total acquired land of the residents by hydropower projects,frequent natural hazards and resultant loss to the local communities due to upcoming construction of hydropower projects surrounding to the Parbati Stage Ⅱ and Ⅲ have been analysed in the paper. Also,the preventive measures to mitigate these adverse impacts have been suggested to strengthen these projects in eco-friendly manner in the mountain context.  相似文献