嵌入式硬件在环UUV模拟器的设计及实现          下载免费PDF全文

黄健 《数字海洋与水下攻防》2018,1(3):68-74

针对 UUV 对高逼真仿真的需求,设计了嵌入式硬件在环 UUV 模拟器。 选用 XMC4800 作为模拟器的主控芯片,设计了最小系统电路和通信接口电路。 给出了数据流图和主要软件算法,包含任务调度算法、任务优先级设计、UUV 模型选择、干扰模型选择和 CAN 应用层协议设计。 模拟器具有多种工作模式, 可以根据不同的应用场景,完成相应的硬件在环仿真,对 UUV 的研制、生产和使用具有一定的参考价值。  相似文献   

基于熵权TOPSIS模型的海岛地区资源环境承载力研究——以舟山普陀区、定海区为例   总被引：2，自引：0，他引：2  

徐文斌  郭灿文  王晶  程义远  徐鹏杰  张宏晔 《海洋通报》2018,(1):9-16

随着海洋强国、"一带一路"、生态文明建设等国家战略的不断推进,海岛在国家政治、军事、经济、社会、生态中的地位不断提高,海岛开发、利用的规模越来越大,其生态保护也面临着新的挑战。本文依据资源环境承载力内涵,兼顾海岛资源环境特点,研究形成海岛地区资源环境承载力评价指标体系,综合应用熵权法、TOPSIS(逼近理想解排序方法)模型评价了典型海岛地区——普陀区与定海区2009-2015年间的资源环境承载力状况,结果表明:普陀和定海资源环境承载力水平呈稳步提升趋势,各个时期的环境保护政策和节能减排相关措施在环境保护与污染治理等方面起到了较为积极的作用。最后,在基于生态系统的海岛综合管理框架内提出了对策建议。  相似文献   

Hydroacoustic estimates of fish biomass and spatial distributions in shallow lakes     

连玉喜  黄耿  Ma?gorzata GODLEWSKA  蔡杏伟  李昌  叶少文  刘家寿  李钟杰 《中国海洋湖沼学报》2018,36(2):587-597

We conducted acoustical surveys with a horizontal beam transducer to detect fish and with a vertical beam transducer to detect depth and macrophytes in two typical shallow lakes along the middle and lower reaches of the Changjiang(Yangtze) River in November 2013. Both lakes are subject to active fish management with annual stocking and removal of large fish. The purpose of the study was to compare hydroacoustic horizontal beam estimates with fish landings. The preliminary results show that the fish distribution patterns dif fered in the two lakes and were af fected by water depth and macrophyte coverage. The hydroacoustically estimated fish biomass matched the commercial catch very well in Niushan Lake, but it was two times higher in Kuilei Lake. However, acoustic estimates included all fish, whereas the catch included only fish 45 cm(smaller ones were released). We were unable to determine the proper regression between acoustic target strength and fish length for the dominant fish species in the two lakes.  相似文献   

Walking Access Distance of Metro Passengers and Relationship with Demographic Characteristics: A Case Study of Nanjing Metro     

Jinliao He  Ruozhu Zhang  Xianjin Huang  Guangliang Xi 《中国地理科学(英文版)》2018,28(4):612-623

In the metropolises of China, the metro plays an increasingly important role in commuting because of its efficiency, affordability, and cleanliness. This paper attempts to explore the relationship between walking access distance to metro stations and the demographic characteristics of passengers, such as age, monthly income, travel frequency, gender, and travel purpose, as well as the influence of the urban context. Nanjing Metro Line 2 is selected as the case study. By using different methods such as a questionnaire survey, spatial decay function, analysis of covariance (ANOVA), network analysis of routes, and K-means cluster analysis, it is suggested that demographic characteristics have a significant impact on the pedestrian walking distance, with the exception of gender. Furthermore, the paper finds a spatial decay effect in walking access distance, the decay rate of which, however, varies across stations. Terminal stations have a larger pedestrian catchment area than in regular and exchange stations. Moreover, the passengers of Nanjing Metro Line 2 can be classified into six groups according to their demographic characteristics, among which education and occupation are vital indicators in determining their willingness to walk to the stations. Middle-class passengers have a higher dependence on the metro and tend to walk longer than other groups do. This study provides an important reference for planners and transport sectors to optimize land-use and transport infrastructures.  相似文献   

底栖有孔虫(Florilus decors)壳体微量元素/钙比值的LA-ICP-MS原位微区分析方法及应用——以长江口外海域为例     

南海明  许博超  黄湘通  杨守业  郭肖伊  王飞飞  邱敏志  张晓洁  于志刚 《海洋学报》2018,40(10):158-166

深海沉积物中有孔虫壳体的微量元素、同位素测试技术已较为成熟，而河口近海沉积物中有孔虫壳体元素微区测试却鲜有报道。本文报道了一种利用激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）分析法测试取自长江口外沉积物中的有孔虫壳体元素/钙比值的技术，研究了氦气载气流量、能量密度、束斑大小、激光剥蚀频率等参数对测试结果的影响，优化了活体有孔虫原位分析方法。应用确定的测试条件对2016年7月取自长江口外的底栖有孔虫优美花朵虫样品（Florilus decors）进行测试，发现Mg、Sr等元素/钙比值在壳体不同位置上无显著差异，而Mn的数据较为离散，可能与有孔虫生长过程中经历的水环境及其变化有关。  相似文献   

Tourism resource assessment and spatial analysis of wine tourism development: a case study of the eastern foothills of China’s Helan Mountains   总被引：1，自引：1，他引：0  

Lei Wang  Ling-en Wang  He Zhu  Jing Lin 《山地科学学报》2018,15(3):645-656

The reasonable development and utilization of mountainous regions closely relates to local economic development and ecological security. The wine production region in the eastern foothills of the Helan Mountains in Ningxia, Ningxia Hui Autonomous Region, with its excellent terroir, is emerging as one of China’s three major geographical attractions. Based on surveys of tourism resources and spatial analysis for this wine producing region, we propose a highly representative and practicable path for wine tourism development. Based on China’s national standard in Classification, Investigation and Evaluation of Tourism Resources (GB/T 18972-2003), which recommended the types and grades of tourism resources in one area, we conduct an analysis of resource characteristics and the current state of development. Using ArcGIS software, spatial autocorrelation analysis, average nearest neighbor analysis, as well as clustering and outlier analysis, we are able to derive the spatial distribution characteristics of tourism resources. Our survey showed that tourism resources in this area are relatively abundant and have good quality and clear combination advantages. Nonetheless, there are resources shortage for wine tourism and poor integration of wine production with the tourism industry. Regarding the spatial distribution of resources, we revealed the current states of and issues surrounding regions with concentrated resources, as well as characteristics of this clustering. Finally, we proposed a development path for wine tourism in this region based on the five dimensions of management mode, industrial path, product development, spatial optimization, and market development.  相似文献   

Soil and Vegetation Spectral Coupling Difference (SVSCD) for Minerals Extraction from Hyperion Data in Vegetation Covered Area     

Shengbo Chen  Shuang Huang  Yanli Liu  Chao Zhou 《中国地理科学(英文版)》2018,28(6):957-972

Remote sensing data have been widely applied to extract minerals in geologic exploration, however, in areas covered by vegetation, extracted mineral information has mostly been small targets bearing little information. In this paper, we present a new method for mineral extraction aimed at solving the difficulty of mineral identification in vegetation covered areas. The method selected six sets of spectral difference coupling between soil and plant (SVSCD). These sets have the same vegetation spectra reflectance and a maximum different reflectance of soil and mineral spectra from Hyperion image based on spectral reflectance characteristics of measured spectra. The central wavelengths of the six, selected band pairs were 2314 and 701 nm, 1699 and 721 nm, 1336 and 742 nm, 2203 and 681 nm, 2183 and 671 nm, and 2072 and 548 nm. Each data set’s reflectance was used to calculate the difference value. After band difference calculation, vegetation information was suppressed and mineral abnormal information was enhanced compared to the scatter plot of original band. Six spectral difference couplings, after vegetation inhibition, were arranged in a new data set that requires two components that have the largest eigenvalue difference from principal component analysis (PCA). The spatial geometric structure features of PC1 and PC2 was used to identify altered minerals by spectral feature fitting (SFF). The collecting rocks from the 10 points that were selected in the concentration of mineral extraction were analyzed under a high-resolution microscope to identify metal minerals and nonmetallic minerals. Results indicated that the extracted minerals were well matched with the verified samples, especially with the sample 2, 4, 5 and 8. It demonstrated that the method can effectively detect altered minerals in vegetation covered area in Hyperion image.  相似文献   

赤潮治理方法综述          下载免费PDF全文

韩锡锡  李琴  曹婧  于文涛  鞠莲 《海洋开发与管理》2018,35(4):76-80

文章综述目前赤潮治理的主要方法,其中物理法重点介绍机械搅动法、超声波法、吸附法和气浮法,化学法重点介绍无机药剂法、有机药剂法和胶体絮凝沉淀法,生物法主要介绍引入赤潮藻类生物天敌、微生物技术和化感技术,分析各自优势和不足,采用微生物技术和化感技术具有重要意义和发展前景。  相似文献   

北京平原地区V_S30估算模型适用性研究   总被引：1，自引：1，他引：0  

江志杰  彭艳菊  方怡  吕悦军  修立伟  黄帅 《震灾防御技术》2018,13(1):75-86

本文使用基于钻孔测井数据的3类模型，即常速度外推模型、速度梯度模型、双深度参数外推模型，通过对北京地区460个深度超过30m的钻孔剪切波速资料进行分析，详细探究了V_S30估算模型在本研究区的适用性。研究结果表明双深度参数外推模型在估算V_S30上准确度很高，其不需要大量的数据进行回归分析，且不具有区域独立性，可以为全球包括北京地区场地类别划分提供依据，进而在震害快速评估中用于确定场地影响，是一种值得推广的估算模型。  相似文献   

High‐T and low‐P metamorphism in the Xilingol Complex of central Inner Mongolia,China: An indicator of extension in a previous orogeny          下载免费PDF全文

Jin‐Rui Zhang  Chun‐Jing Wei  H. Chu 《Journal of Metamorphic Geology》2018,36(4):393-417

The Xilingol Complex comprises biotite gneisses and amphibolite interlayers with extensive migmatization. Four representative samples were documented and found to record either two or three metamorphic stages. Phase modelling using thermocalc suggests that the observed assemblages represent the final stages that underwent cooling from temperature peaks, and are consistent with a fluid‐absent solidus in P–T pseudosections. Their P–T conditions are further constrained to be 5–6 kbar/680–725°C and 4–5 kbar/650–680°C for two garnet‐bearing gneiss samples, 4–5 kbar/660–730°C for a cordierite‐bearing gneiss sample, and 4–5 kbar/680–710°C for an amphibolite sample based on mineral composition isopleths, involving measured Mg content in biotite, anorthite in plagioclase, grossular and pyrope in garnet and Ti content in amphibole. The peak temperature conditions recovered are 760–790°C or >760°C at 5–6 kbar based on the composition isopleths of plagioclase, biotite, garnet and especially the comparison of melt contents between the calculated and observed. A pre‐peak heating process with slight decompression can be suggested for some samples on the basis of the core–rim increase in the plagioclase anorthite, and the stability of ilmenite. Zircon U–Pb dating using the LA‐ICP‐MS method provides systemic constraints on the metamorphic ages of the Xilingol Complex to be 348–305 Ma, interpreted to represent the post‐peak cooling stages. Moreover, metagabbroic dykes that intruded into the Xilingol Complex yield 317 ± 3 Ma from magmatic zircon, and are considered to have played a significant role for heat advection triggering the high‐T and low‐P metamorphism. Thus, the clockwise P–T paths involving pre‐peak heating, peak and post‐peak cooling recovered for the Xilingol Complex are consistent with an extensional setting in the Carboniferous that developed on a previous orogen in response to addition of mantle‐derived materials probably together with upwelling of the asthenospheric mantle.  相似文献