Classification of topological relations between spatial objects in two‐dimensional space within the dimensionally extended 9‐intersection model          下载免费PDF全文

Jingwei Shen  Min Chen  Xintao Liu 《Transactions in GIS》2018,22(2):514-541

As an important topological relation model, the dimensionally extended 9‐intersection model (DE‐9IM) has been widely used as a basis for standards of queries in spatial databases. However, the negative conditions for the specification of the topological relations within the DE‐9IM have not been studied. The specification of the topological relations is closely related to the definition of the spatial objects and the topological relation models. The interior, boundary, and exterior of the spatial objects, including the point, line, and region, are defined. Within the framework of the DE‐9IM, 43 negative conditions are proposed to eliminate impossible topological relations. Configurations of region/region, region/line, line/line, region/point, line/point, and point/point relations are drawn. The mutual exclusion of the negative conditions is discussed, and the topological relations within the framework of 9IM and DE‐9IM are compared. The results show that: (1) impossible topological relations between spatial objects can be eliminated by the application of 43 negative conditions; and (2) 12 relations between two regions, 31 relations between a region and a line, 47 relations between two lines, three relations between a region and a point, three relations between a line and a point, and two relations between two points can be distinguished by the DE‐9IM.  相似文献   

鄂尔多斯盆地中上三叠统延长组长7段碳酸盐结核成因讨论     

朱如凯  崔景伟  罗忠  李森  毛治国  葸克来  苏玲 《地质学报》2021,95(11):3442-3454

鄂尔多斯盆地南部铜川地区露头区中三叠统延长组长7段细砂岩、粉砂岩、泥质粉砂岩、粉砂质泥岩层序中发育有大量圆球状、椭球状、扁球状碳酸盐岩结核,对于其成因存在争议.对铜川地区多个剖面的结核开展宏观描述,在微观薄片观察基础上开展岩石矿物组成、稳定同位素、簇同位素以及微区同位素等分析,特别是选取一个结核开展了详细的解剖.结果显示结核成分以方解石为主,少量白云石;内部结构有差异,在球体横切面上明显分为两个圈层;碳同位素值正偏,由内部圈层向外部圈层降低;氧同位素与碳同位素变化趋势一致,计算结核形成古温度变化区间为28.6～76.5℃;簇同位素揭示结核中部形成温度为42.9℃.认为该类结核为早期发酵带内细菌参与甲烷生成作用形成,甲烷菌活动引起有机质碳同位素分馏,碳酸盐结核中方解石和白云石圆球粒可能是蓝细菌细胞方解石化或白云石化的结果.根据埋藏史,认为该类结核形成于成岩作用早期,后期在成岩过程中叠加生长,同心环层结构明显.  相似文献   

准噶尔盆地阜北地区头屯河组非均质性综合研究     

于景维  牛志杰  祁利祺  孙新铭  柳妮  张进  曹嵩 《现代地质》2021,35(3):819-831

对准噶尔盆地阜康凹陷北部斜坡区(阜北地区)中侏罗统头屯河组储集层非均质性进行探讨,为研究区头屯河组储集层深入勘探提供指导。综合运用钻测井、岩心描述、薄片、粒度、(恒速)压汞曲线以及核磁曲线等资料,对研究区头屯河组储集层的微观、宏观非均质性以及非均质性的控制因素进行详细分析。结果表明:头屯河组储集层发育2类孔隙结构,造成储层微观非均质性较强;储集层包含3类粒度韵律、2类渗透率韵律以及2类夹层不均匀分布导致层内非均质性较强,分层系数以及砂地比不均导致层间非均质性较强,变异系数、突进系数和非均质性系数反映平面非均质性较强,宏观非均质性整体表现较强。沉积环境和成岩环境对头屯河组储集层非均质性程度都有影响,以成岩环境为主。最终认为研究区勘探目标区为应首选头一段河道砂体主体区域。  相似文献   

准噶尔盆地阜东斜坡区中上侏罗统储集层特征差异及控制因素分析   总被引：1，自引：0，他引：1  

于景维  叶勇  柳妮  朱永才  文华国 《地质学报》2018,92(5):1070-1080

准噶尔盆地是中国西部地区最重要的含油气盆地之一,阜东斜坡区中上侏罗统头屯河组和齐古组是近期勘探重点。根据野外露头、钻井岩芯和分析化验资料,详细分析头屯河组和齐古组储集层特征差异,包括储集层岩矿特征和物性特征差异。岩矿特征中重点对碎屑、填隙物以及孔隙类型和结构特征进行对比分析,物性特征中重点对储集层类型进行研究,发现齐古组储集砂层储集质量总体上要好于头屯河组。通过综合分析,认为阜东斜坡区中上侏罗统储集层特征差异主要受构造、沉积相、异常压力和成岩作用复合控制,构造演化的差异是导致头屯河组和齐古组储集层特征差异的最关键因素,头屯河组物性最好储集层的微相类型为水下分流河道,齐古组物性最好储集层的微相类型为分流河道,异常压力对原生孔隙保存以及黏土矿物发育位置起到重要影响,成岩作用对于重点层位储集层物性好坏起到决定性作用,其中凝灰质的蚀变序列对于后期油气开发有重要参考价值。  相似文献   

基于大尺度海温因子的江苏省水稻适宜移栽期预报模型研究     

高苹  徐敏  徐经纬  于庚康  单婵 《气象》2015,41(12):1538-1544

利用江苏有记录以来的农业气象资料,分析发现江苏水稻适宜移栽期与播栽期≥10℃有效积温间存在极显著的正相关关系,因此,可通过有效积温确定适宜移栽期。根据海气相互作用原理,基于遥相关方法,寻找有效积温的海温响应相关区,应用最优相关技术和空间拓扑分析法,筛选出高相关海温预报因子,并通过稳定性和独立性检验,确保海温预报因子的可靠性,最终建立水稻适宜移栽期的长期预报模型,经过历史拟合和试报检验,预报模型效果理想,至少可提前半个月预报出水稻适宜移栽的日期,预报结果对农业生产具有重要的实用价值。  相似文献   

Isolation and Biochemical Characteristics Analyses of Phenoloxidases (POs) in Three Cultured Mollusk Species     

SONG Xiangdi  JIANG Jingwei  XING Jing  ZHAN Wenbin 《中国海洋大学学报(英文版)》2022,21(2):465-472

Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk species,including scallop Chla-mys farreri,abalone Haliotis discus hannai and clam Scapharca subcrenata.The POs were isolated from hemocytes using linear-gradient native-PAGE combined with catechol staining.The PO activities and their characters were investigated.The molecular mass of PO in C.farreri was 576 kDa,and it was 228 kDa in H.discus hannai.In S.subcrenata,four POs were detected and their mole-cular masses were 391 kDa,206 kDa,174 kDa and<67 kDa,which were named as 391-PO,206-PO,174-PO and s-PO,respectively.Ki-netic analyses indicated that all of the POs,except for 391-PO had higher affinity to L-DOPA and catechol than to hydroquinone and dopamine.However,all of the POs failed to oxidize tyrosine.The effects of divalent metal ions on POs’activities were assayed,in-cluding Fe²⁺,Mg²⁺,Zn²⁺,Mn²⁺,Cu²⁺and Ca²⁺from FeCl₂,MgSO₄,ZnSO₄,MnCl₂,CuSO₄and CaCl₂.The POs were inhibited by Fe²⁺at all determined concentrations.Additionally,the inhibition assay showed that all of the POs were inhibited by cysteine,ascorbic acid,sodium sulfite,citric acid,ethylenediaminetetraacetic acid disodium(EDTA)and sodium diethyldithiocarbamate(DETC).The inhibition effects of critric acid and EDTA are dose-dependent.H.discus hannai PO and 391-PO were slightly inhibited by sodium azide,and H.discus hannai PO,391-PO and 174-PO were slightly inhibited by thiourea.In conclusion,the POs in the three cultured mollusks are copper-containing laccase-type phenoloxidases with similar biochemical characteristics even though their molecular masses are different.  相似文献   

黄河三角洲景观格局变化及生态风险评价          下载免费PDF全文

刘冰  王靖伟  吴福荣  吴明阳  罗松  陈慧  韩斌 《山东国土资源》2023,39(5):39-45

黄河三角洲具有极高的生态价值,研究其景观格局及生态风险对促进黄河三角洲高质量发展具有重要意义。本文以黄河三角洲1980年、2000年和2020年土地利用数据为基础,分析土地转移及景观格局特征,同时构建生态风险评价模型揭示生态风险时空演变及空间相关性。结果表明：(1)耕地是黄河三角洲最主要的地类,占比在60%以上,1980—2020年土地转移主要发生在耕地、建设用地、水域和未利用地之间。(2)1980—2020年黄河三角洲景观斑块数、景观斑块密度、景观最大斑块指数、景观形状指数和香农多样性指数均呈下降趋势,区域整体趋向简单化和聚集化。(3)黄河三角洲高风险区和较高风险区主要环渤海分布,1980—2020年各级风险区转出最大面积均为更低级风险区,生态风险有所降低。  相似文献   

湖北清江和尚洞洞顶植物叶片和土壤的类脂物对比及其意义          下载免费PDF全文

崔景伟  黄俊华  蒲阳  黄咸雨  谢树成 《第四纪研究》2008,28(1):35-42

用GC-MS对湖北清江岩溶地区和尚洞洞顶植物叶片与该洞上覆土壤层中的类脂物进行了分析和对比。在植物叶片中检测出了一系列直链烷烃、脂肪酸、以及丙三醇、植醇和甾醇等类脂物,其中直链烷烃的碳数分布范围大体在C21～C36之间,以C29或C31为主峰且具有奇偶优势;脂肪酸的分布主要集中在中、短链脂肪酸内（C数<23）,以C16为主峰呈单峰型分布且具有偶奇优势;醇的分布很不规则,仅检测出丙三醇,植醇和三种甾醇,没有检测到脂肪酮类化合物。与之相比,洞顶上覆土壤层中检测出更加丰富的类脂物。类脂物具有如下特征:正构烷烃以C31为主峰,还存在低碳数正构烷烃和异构烷烃,如2-甲基、3-甲基、4-甲基、5-甲基、6-甲基、7-甲基、8-甲基等一系列的单甲基支链烷烃,这些支链烷烃显示了微生物的贡献;脂肪酸分布也以低碳数的C16为主峰,且低碳数脂肪酸的含量较植物叶片中明显的增加,同时一些异构和反异构脂肪酸（C14∶0,C15∶0和C17∶0）以及一些单不饱和脂肪酸（C16∶1,C17∶1,C18∶1和C20∶1）也被检测到,也表明土壤中的脂肪酸不仅存在高等植物的贡献,还存在微生物的来源;没有植醇,但出现姥鲛烷和植烷并检测到了一系列脂肪醇化合物,碳数分布在C21～C36之间;检测到一系列的酮,具有奇偶优势,碳数分布范围在C23～C30和C33。高等植物叶片和土壤的差异反映了微生物对高等植物类脂物输入到土壤过程的重要贡献。本研究工作不仅提供了该岩溶地区植物叶片的类脂物信息,还为研究土壤有机质的来源和植物叶片中类脂物在地质过程中的转变提供信息,更为研究岩溶地区滴水和石笋中类脂物的来源提供一定的参考。  相似文献   

Pollen and spores from Lower Cretaceous in Guyang Basin of Inner Mongolia,China and their palaeoclimatic and paleoecological significance          下载免费PDF全文

Peihong Jin  Jingwei Chen  Zixi Wang  Xiaohui Xu  Guolin Yang  Baoxia Du  Bainian Sun 《Island Arc》2017,26(5)

Research on the climate and vegetation of the Cretaceous is fundamental to understanding the present environment. The present study focuses on the Lower Cretaceous Guyang Formation (Inner Mongolia), which yields unique macrofossils and diverse palynological assemblages that are used to understand the palaeoecology. In total, 56 genera are identified in the examined assemblage, which are dominated by spores and pollen of pteridophytes and gymnosperms. The gymnosperm pollen is dominated by Taxodiaceae, which belong to Coniferales, and a large proportion of pollen attributable to the Cycadophyta and Ginkgopsida. The pteridophyte spores are dominated by taxa attributable to the Lygodiaceae and Cyatheaceae. Quantitative analysis based on the geographical distribution of modern plant communities and the Sporomorph Ecogroup (SEG) model, the palynomorph associations are used to infer the presence of a closed coniferous forest dominated by Podozamitales, Picea and Podocarpus with understory vegetation comprising ferns prevailed. The fossil palyno flora indicates a warm and humid subtropical climate during Early Cretaceous of Inner Mongolia.  相似文献   

Topological relations between a directed line and a directed region     

Jingwei Shen  Yang Huang  Min Chen 《Transactions in GIS》2020,24(2):526-548

Representing the topological relations between directed spatial objects has gained increasing attention in recent years. Although topological relations between directed lines and other types of spatial objects, such as regions and bodies, have been widely investigated, few studies have focused on the topological relations between directed lines and directed regions. This research focuses on the representation and application of directed line–directed region (DLDR) topological relations, and may contribute to spatial querying and spatial analyses related to directed spatial objects or time‐varying objects. Compared with other topological relation models, a DLDR model that considers the starting and ending points of the directed line and the front and back faces of directed regions is proposed in this research to describe the topological relations between directed lines and directed regions. DLDR topological relations are presented, the completeness of the 111 DLDR topological relations is proved, and the topological relations based on the 9‐intersection model (9IM), 9⁺‐intersection model (9⁺‐IM), and DLDR model are compared. The formalism of the DLDR model and the corresponding geometric interpretations of the 111 DLDR topological relations are presented, seven propositions are stated to prove the completeness of the 111 DLDR topological relations, and the case study shows that more detailed topological relation information can be obtained based on the DLDR model.  相似文献