星基空间人造飞行器探测概率分析

随着空间飞行器数量的日益增多,空间碰撞的概率也逐步加大。为了确保自身飞行器的安全,同时为了减少对目前在轨的飞行器的干扰,通过某种途径来感知空间飞行器的信息,包括轨道和结构外形等参数,是十分必要的。除了地基手段对空间飞行器进行观测外,星基空间飞行器探测是一种不可或缺的补充手段。文章通过对所掌握的空间飞行器数据库,给出了基于地球低轨道观测卫星情况下,星基空间飞行器探测概率的统计结果。     

省级基础测绘1∶1万比例尺数字测绘产品的质量检验

省级基础测绘1∶1万比例尺数字测绘产品包括DEM,DOM,DLG,DRG、元数据、文档簿等。为验证数字测绘产品最终成果的精度和可靠性,可选择多种方案进行质量检验;在选择检验方案时,既要考虑检验的成本、周期,又要考虑检验方案的科学性和严密性。针对不同的数字测绘产品,该文给出了与之相适应的检验方法,并阐明了检验内容和注意事项。     

Design and elementary realization of the Vision Earth System

The Vision Earth System is a interactive system by employing B/S model. The system has the function of query display and mutuaUy displays relevant geologic information, integrating image information of one outcrop and realizing 3D geologic visualization. In this system, the basis is effective store, transmitting, display and quick query of enormous images and their properties data. From Java technology, this essay researches the elementary realization of Vision Earth System by adopting store formality of enormous images database,quick display image of website and quick image storage method.     

人类活动对海洋生态系统影响的空间量化评价——以莱州湾海域为例

本文针对海域管理中难以量化人类活动对海洋生态系统影响的问题,提出人海关系空间量化模型,通过完善概念模型、构建指标体系、确定权重及标准,最终利用作用强度和位置关系量化人类活动对海洋生态系统的影响,数值在0—1之间,等分为四个影响程度,由弱到强依次为微弱、中等、强烈和极强,并将该模型和量化方法应用于莱州湾海域。研究结果表明:整个莱州湾受人类活动的综合影响均值为0.425,处于中等影响程度;其中污水排放、围填海工程及港口航运是对莱州湾生态系统影响比较强烈的人类活动;研究海域中40%受到人类活动的强烈影响,44%为中等影响,16%为微弱影响。空间量化分析显示,人类活动对莱州湾近岸海域的综合影响比邻近外海强烈,其中影响较强烈的区域出现在西南近岸海区,而影响较微弱的海区则为莱州湾北部外海。该方法空间量化结果与莱州湾实际情况相符,说明人海关系空间量化模型适合定量化评估人类活动对该海域生态系统的影响,可为"山东半岛蓝色经济区"海域管理提供技术支持。     

Grain size composition and transport of sedimentary organic carbon in the Changjiang River (Yangtze River) Estuary and Hangzhou Bay and their adjacent waters

Surface sediments from the Changjiang River(Yangtze River) Estuary,Hangzhou Bay,and their adjacent waters were analyzed for their grain size distribution,organic carbon(OC) concentration,and stable carbon isotope composition(δ13C).Based on this analysis,about 36 surface sediment samples were selected from various environments and separated into sand(0.250 mm,0.125–0.250 mm,0.063–0.125 mm) and silt(0.025–0.063 mm)fractions by wet-sieving fractionation methods,and further into silt-(0.004–0.025 mm) and clay-sized(0.004mm) fractions by centrifugal fractionation.Sediments of six grain size categories were analyzed for their OC andδ13C contents to explore the grain size composition and transport paths of sedimentary OC in the study area.From fine to coarse fractions,the OC content was 1.18%,0.51%,0.46%,0.42%,0.99%,and 0.48%,respectively,while theδ13C was –21.64‰,–22.03‰,–22.52‰,–22.46‰,–22.36‰,and –22.28‰,respectively.In each size category,the OC contribution was 42.96%,26.06%,9.82%,5.75%,7.09%,and 8.33%,respectively.The OC content in clay and fine silt fractions(0.025 mm) was about 69.02%.High OC concentrations were mainly found in offshore modern sediments in the northeast of the Changjiang River Estuary,in modern sediments in the lower estuary of the Changjiang River and Hangzhou Bay,and in Cyclonic Eddy modern sediments to the southwest of the Cheju Island.Integrating the distribution of terrestrial OC content of each grain size category with the δ13C of the bulk sediment indicated that the terrestrial organic material in the Changjiang River Estuary was transported seaward and dispersed to the Cyclonic Eddy modern sediments to the southwest of the Cheju Island via two pathways:one was a result of the Changjiang River Diluted Water(CDW) northeastward extending branch driven by the North Jiangsu Coastal Current and the Yellow Sea Coastal Current,while the other one was the result of the CDW southward extending branch driven by the Taiwan Warm Current.     

一种高频雷达回波谱反演海浪的新算法

在高频地波雷达海浪谱反演问题中,广泛采用的Barrick后向散射公式属于第一类非线性Fredholm积分方程。此类积分方程的解在本质上是不适定的,加之高频雷达二阶回波信号信噪比较低,使得反演海浪谱存在解不稳定的问题。本文提出一种稳定且低复杂度的反演算法,此算法首先根据高频雷达一阶回波谱测量海浪方向,并将其引入积分方程求解过程,减少求解变量的个数,降低反演算法的复杂度。为解决反演结果不稳定的问题,使用Tikhonov正则化方法并利用广义交叉验证法(GCV)确定其正则化系数。通过在不同测试条件下对反演算法的仿真测试分析,表明此方法具有运算量小、稳定性好的特点。     

利用不同盐度诱导长牡蛎三倍体的研究

采用低盐度(4、6、8、10、12、14、16)和高盐度(40、45、50、55、60、65、70)在40%~50%受精卵出现第一极体时处理10和15min,进行长牡蛎三倍体的诱导。在低盐度诱导三倍体实验中,随着盐度降低,D型幼虫孵化率逐渐降低,处理10和15min的卵裂率差异显著(P0.05),孵化率差异不显著(P0.05)。当盐度为8时,处理受精卵10与15min,三倍体诱导率最高分别可达84.4%和91.0%,两处理组三倍体诱导率差异显著(P0.05)。在高盐度诱导三倍体实验中,随着盐度升高,D型幼虫孵化率逐渐降低,处理10和15min的卵裂率和孵化率均差异显著(P0.05)。当盐度为55时,处理受精卵10min,三倍体诱导率最高为80.3%;当盐度为60时,处理受精卵15min,三倍体诱导率最高为97.1%,两处理组三倍体诱导率差异显著(P0.05)。研究发现,在盐度为8和60条件下,40%~50%的受精卵出现第一极体时,处理15min,长牡蛎三倍体诱导率最高。     

碳纳米管和纳米二氧化钛复合光催化剂处理海洋柴油污染的研究

利用溶胶凝胶法自制了碳纳米管和纳米二氧化钛的复合光催化剂,采用投射电子显微镜和X光衍射仪对粉体的粒径、物象、形貌和热稳定性等进行表征。通过研究光照条件、催化剂的投加量、油的初始浓度、催化剂制备的煅烧条件等因素,考察了自制碳纳米管和纳米二氧化钛的复合催化剂对降解模拟海洋柴油污染的海水去除率的影响。研究发现,在可见光照条件下,400℃煅烧2 h的复合催化剂,投加量为0.4 g/L、柴油的初始浓度为0.6 g/L、反应的光照时间为4 h时效果最好,去除率可达到67.65%。     

Numerical and Experimental Analysis of A Ducted Propeller Designed by A Fully Automated Optimization Process Under Open Water Condition

A fully automated optimization process is provided for the design of ducted propellers under open water conditions, including 3D geometry modeling, meshing, optimization algorithm and CFD analysis techniques. The developed process allows the direct integration of a RANSE solver in the design stage. A practical ducted propeller design case study is carried out for validation. Numerical simulations and open water tests are fulfilled and proved that the optimum ducted propeller improves hydrodynamic performance as predicted.     

基于主成分分析的相对重力观测零漂和固体潮提取

利用主成分分析PCA提取2014-08-15~23CG-5相对重力仪静态相对观测的零点漂移和固体潮。结果显示,PCA提取的零点漂移值与最小二乘线性拟合结果非常一致,其差仅在10-2μGal/d量级;PCA估算的固体潮值与CG-5重力仪内部软件提供的固体潮模型计算值统计结果基本一致,两者之差均小于8μGal,均方根均小于5μGal。