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基于AutoCAD数据建立地理信息系统空间数据库的方法初探 总被引:1,自引:0,他引:1
钱成越 《成都信息工程学院学报》2010,25(4):395-398
针对现有AutoCAD数据导入GIS(地理信息系统)空间数据库的需求,在阐述AutoCAD数据与GIS数据特点的基础上,分析了数据库建立过程中遇到的困难及解决措施,提出了3种利用AutoCAD数据建立GIS空间数据库的方法,并将其运用于广东省南海市某县的城市信息化工作,取得较好效果,证明了方法的可行性与实用性。 相似文献
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国土规划是空间规划体系中层级最高的规划,是国土资源开发利用与整治保护相关规划编制的重要基础。要做好相关规划,需要对规划区内自然、经济、社会等数据集进行灵活有效的利用和组合。针对国土规划编制中对多源异构空间、非空间数据集成和抽取特定数据的迫切需求,提出了一种基于虚拟数据库的国土规划多源异构数据集成方法,利用虚拟数据库实现分布式数据源的虚拟组织与透明访问,用GML实现多源异构数据格式的标准化,并开发了国土规划信息共享原型系统,在此基础上进行了实践使用。从现有数据库中抽取相应的数据集和数据项,构建全局虚拟数据库,由于虚拟数据库并不改变现有数据库的应用系统工作模式,保证了原始数据更新的有效性,以及数据的完整性。 相似文献
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全球离散格网系统是一种面向全球的新型多分辨率数据建模与表达解决方案。与三角形和四边形格网相比,六边形格网具有对称性好、采样效率高、一致相邻等特点,更利于地球空间信息的建模、整合与分析。本文提出一种能生成各种六边形格网系统的算法,将正八面体上的相邻三角面组合为“四边形逻辑结构”,建立三轴离散斜坐标系,描述不同六边形剖分产生的多分辨率格网。其采用面向对象的思想设计了软件模型,通过实验验证了算法的可行性,分析了算法的效率。结果表明,该算法采用统一的数学模型描述正八面体上各种类型六边形剖分产生的离散格网系统,对应的软件模型,将不同格网系统的共性特征和个性特征分离,便于维护和扩展,具有一定的灵活性。 相似文献
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在研究现有手持终端设备中文输入法及汉字库的基础上,提出了一种可以适合一般程序框架Qt的中文全拼输入法汉字库生成方法。使用该方法生成的汉字库结构合理,可以支持所有嵌入式Qt环境中的可显示汉字。经分析和实践验证,全拼输入法汉字库设计以及汉字库的生成方法非常适合ARM-Linux系统的全拼中文输入法使用。 相似文献
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基于MGEX(multi-GNSS experiment)测站实测数据,采用系统间交叉验证方法检核海上BDS/GNSS精密单点定位质量。分析不同系统组合的精密单点定位精度和收敛速度,结果表明,相对于单BDS,不同系统组合可有效提高精密单点定位的收敛速度和定位精度;组合系统的数目越多,相应的精密单点定位精度越高,收敛速度越快。同时,在静态、仿动态、海上动态不同定位模式下,采用系统间交叉验证方法检核精密单点定位的精度和可靠性。 相似文献
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LANG Xuqian LI Yang SUN Guohui ZHOU Zhongzheng LI Jing FENG Chao KONG Ming LIU Ya CHENG Xiaojie CHEN Xiguang 《中国海洋大学学报(英文版)》2020,19(2):459-465
Uniform molecular weight(Mw)chitosan(CS)is highly demanded in medical biomaterial industry.This present article described heterogeneous degradation of CS in aqueous HCl/ethanol solution,in which progress uniform Mw CS was successfully prepared.The Mw distribution of CS was measured by gel permeation chromatography(GPC)analysis.Moreover,the structure and properties of degraded CS were characterized by Fourier transform infrared spectroscopy(FT-IR),nuclear magnetic resonance spectroscopy(^1H NMR),X-ray diffraction(XRD)and thermogravimetric(TG)analysis.In addition,the biocompatibility of degraded CS was also assessed by hemolysis rate(HR)measurement.The Mw of CS dramatically decreased from 246 KDa to 76 k Da at the initial 30 min,and stabilized at 18 kDa after 24 h.GPC analysis results showed that the degraded CS molecular become homogenization.FT-IR and 1 H NMR analysis confirmed the basic structure of CS molecular backbone was not destroyed during this progress.Besides,the water solubility of CS was not significantly influenced by this reaction.Moreover,the XRD analysis revealed that crystallinity of degraded CS increased from 70.32% to 99.25%with time.The TG analysis showed improved thermal stability of degraded CS.HR measurement demonstrated the degraded CS possessed excellent biocompatibility.This simple and efficient heterogeneous degradation would open up a new route to produce uniform Mw CS. 相似文献
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我国古代先进的社会经济文化孕育了为数众多的古村落。本文分析了近些年我国古村落研究的基本特点,并以文化景观基因学说分析了古村落景观基因信息图谱平台构建的内容与意义,以及其关键技术与解决方案。同时,讨论了该程序的基本框架和主要功能、需求分析、功能模块划分与实现思路。最后,以湖南江永女书为例,对古村落景观基因信息进行了提取实验。 相似文献
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该文简单回顾了国土资源信息系统建设的特点,明确了国土资源数据对系统功能的支撑作用,归纳了国土资源数据中心建设对于行业信息化建设的核心意义。该文基于信息化实践,初步规划了国土资源数据中心的业务内容和逻辑框架,以期为行业信息化规划和建设提供有益帮助。 相似文献
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培育规范土地市场是深化土地使用制度改革的一项重要内容。莱西市国土资源局土地储备中心坚持规范与搞活并举,积极培育土地"阳光市场",使土地使用制度更加健全、规范、有序,为促进莱西市经济和社会发展做出了积极的贡献。 相似文献
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《中国海洋大学学报(英文版)》2019,(6)
Nassarius causes many poisonings in China and other Asian countries. The toxicity of Nassarius is related to species and populations. However, the molecular assignment of different toxic Nassarius samples is still unclear, which deteriorates the poisoning. Our study combined toxicity, toxin detection and multiple genes DNA barcoding to assign the various toxic Nassarius species and populations from China coast. The toxicity test indicated that different Nassarius species and different populations within one Nassarius species had different toxicity. Based on High Performance Liquid Chromatography, the toxin was confirmed to be TTX. The toxin content varied in different samples. The COI, 16 S and ITS sequences revealed different toxic Nassarius species as monophyletic clades. All the samples tested have been assigned to species level. However, the different toxic populations within N. succinctus, N. variciferus and N. semiplicata did not form separated clades, and the toxic and nontoxic species did not form two clades separately. Our study constructed the relationship between toxicity and taxonomy assignment of different toxic Nassarius samples based on toxicity detection and multiple gene DNA barcoding, which provides the basis for controlling poisoning and studying the toxin-resistance difference in Mollusca. It is also indicated that the toxicity of Nassarius is really related with species at the genetic level, but not absolutely related with populations. 相似文献
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克隆并测定了星洲银罗非鱼(Oreochromis sp.)细胞色素b基因(cyt b)的全序列,得到全长1 141bp的序列用于分析,用MEGA4.0分析软件与GenBank中的线粒体DNA序列进行序列比较,显示星洲银罗非鱼与其他鱼类的cyt b基因的同源性较高,同源度介于83%~93%间;根据星洲银罗非鱼与莫桑比克罗非鱼、尼罗罗非鱼等12种鱼类的cyt b基因序列构建的系统进化树,初步确定尼罗罗非鱼、莫桑比克罗非鱼为星洲银罗非鱼的父母本。 相似文献
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《中国海洋大学学报(英文版)》2019,(6)
Sensitivity is crucially important for surface-enhanced Raman spectroscopy(SERS) application to detect trace-level polycyclic aromatic hydrocarbons(PAHs) in the seawater. In this study, a high sensitivity three-dimensional(3-D) SERS substrate composed with syringe filter, glycidyl methacrylate-ethylene dimethacrylate(GMA-EDMA) porous material and optimal parameters(57 nm, pH 13) gold nanoparticles(Au NPs) was developed for the detection of PAHs in water. The enhancement effect and repeatability of this 3-D substrate were also explored. The Raman intensity of pyrene using 3-D SERS substrate is about 8 times higher than that of substrate only using p H 13 gold colloid solution and about 12 times higher than that of substrate using natural Au NPs and GMA-EDMA porous material, which means both the pH 13 AuN Ps and the GMA-EDMA porous material are important factors for the sensitivity of this 3-D SERS substrate. Good repeatability of this optimal 3-D substrate was obtained. The relative standard deviation(RSD) is less than 8.66% on the same substrate and less than 3.69% on other different substrates. Four kinds of PAHs, i.e., phenanthrene, pyrene, benzo(a)pyrene, benzo(k)fluoranthene and their mixture, were detected at the different concentrations. Their limits of detection(LODs) are 8.3×10~(-10)(phenanthrene), 2.1×10~(-10)(pyrene), 3.8×10~(-10)(benzo(a)pyrene) and 1.7×10~(-10) mol L-1(benzo(k)fluoranthene), respectively. In addition, these four PAHs were also detected by fluorescence spectroscopy to evaluate the sensitivity of SERS technology using this optimal 3-D SERS substrate. The results showed that the sensitivity of SERS based on the 3-D SERS substrate even using the portable Raman system was closed to that of fluorescence spectroscopy. Therefore, the SERS technology using this optimal 3-D substrate is expected to be an in-situ method for the detection of environmental PAHs. 相似文献
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《广东海洋大学学报》2019,(6)
【目的】设计一种适用于大规模网箱养殖的船载式投饵系统。【方法】投饵系统主要由上料装置、下料装置、动力装置、抛撒装置和集中控制系统组成,并安装固定于船舷,进行饵料投喂。其中,以PLC作为集中控制系统的控制核心,通过触摸屏界面实现设备的启停、投料速度调控、运行状态监控及网箱饵料投喂数据的记录等。对投饵系统样机进行试验研究。【结果与结论】投饵系统的投饵速度在0~230 kg/min范围内可调,投饵量精度误差为0.1~1.6 kg,满足容积为127.3~1 145.9 m3的深水网箱投喂要求,降低养殖人员的劳动强度。 相似文献
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根据国土资源部《国土资源信息化“十五”规划和2010年远景目标(纲要)》和山东省国土资源厅《关于加快国土资源信息化建设工作的意见》,菏泽市国土资源局组织建设菏泽市“数字国土”工程。“菏泽数字国土”工程,广义上是指通过建设宽带多媒体信息网、地理信息系统等基础设施平台,整合全市国土资源管理信息资源,实现国土资源管理和公共服务领域的信息化。 相似文献