空间和属性双重约束下的自组织空间聚类研究

形式化定义了双重聚类的聚类准则及其判定方法,提出了双重聚类的两步法求解思路和自组织双重聚类算法。通过实例验证了该算法的可行性,自组织双重聚类可以发现非空间属性的聚集、延伸等空间分布特征,可以发现任意复杂形状的聚类,并降低了人为影响。     

搭格架温泉水化学特征及其约束因素研究

搭格架地热区温泉水DJ1-DJ116号样品于2009年采集,阳离子及微量元素含量采用ICP-OES法测试,Cl-含量采用滴定法测试,其余阴离子含量采用紫外-可见光分光光度法测试。通过对温泉水化学指标的分析,研究温泉的水化学特征及约束因素。其温泉水化学类型为HCO3-Na型,平均矿化度为1 524 mg/L,具有较高的Na/Cl值,温泉水演化程度较高,为完全平衡水,热储中的水岩反应达到了平衡状态.温泉水中PO2极低,PCO2较高;大部分温泉水中玉髓、石英和无定形态SiO2三种硅质热液矿物的饱和度指数大于0。K-Na温标计算热储平均平衡温度为251.36℃;泉水中的Na＋、K＋离子活度主要受到钠、钾长石的约束。微量元素组合表现出花岗岩源的特征。总体上搭格架地热区温泉水化学特征受到区域地质背景的约束。     

ICT对居民时空行为影响研究进展

以计算机为核心的ICT凭借网络飞速发展,渗透到社会生活的各个领域,对居民日常生活产生了巨大影响,引发了地理、交通、规划学者的关注.本文对国内外ICT对居民时空行为的影响研究进行综述.从地理学的视角出发,分别从时空制约、破碎化、多任务以及ICT活动的可视化与数据管理几个角度,论述了国外ICT对居民时空利用的影响研究.从交...     

约束非线性规划的一种信赖域方法

研究了一类具有等式约束的非线性规划，提出了一种信赖域方法，并且在一定条件下证明了所给算法是全局收敛的。     

Distribution Patterns of Synechococcus Indicated Their Environmental Constraints and Related Geochemical Processes in the Yellow Sea

Synechococcus is a widely distributed photosynthetic pico-phytoplankton,which contributes mainly to carbon fixation and maintains the stability of the marine ecosystem.To investigate its distribution patterns in the Yellow Sea,seawater samples were collected during September 2018.Results of flow cytometry analysis showed that the Synechococcus abundance ranged from 6.36×10² to 4.51×10⁴ cells mL^?1,which correlated with salinity(P<0.01)and temperature(P<0.05).At deeper off-shore sites,Synecho-coccus showed high abundance at the subsurface thermo-halocline,which was in accordance with chlorophyll a(Chl a)content along the vertical column.Based on the high-throughput sequencing data of rpoC1(partial gene encoding RNA polymerase),two Synechococcus subclusters,S5.1 and S5.2,were found to coexist in the studied area.Several clades of S5.1,including Clades I,II,and III,were the dominant components,accounting for 6.63%,26.11%,and 45.5%of the total genus,respectively.Redundancy analysis(RDA)showed that nitrite was the main environmental factor that explained the genus composition among samples.Fur-thermore,co-occurrence network revealed that the main phyla that coexisted with Synechococcus were Proteobacteria,Bacteroidetes,Actinobacteria,Planctomycetes,and Verrucomicrobia,which were involved in the carbon(C),nitrogen(N),sulfur(S),and manga-nese(Mn)cycles.Overall,Synechococcus exhibited biogeographic distribution correlated with temperature-salinity and nitrite in the Yellow Sea,and their geochemical function showed diverse but should be further verified in the future.     

江西三百山盆地粗面岩锆石年代学与地球化学制约

三百山盆地的粗面岩主要出现在盆地东部仰天湖破火山口构造中,粗面岩锆石SHRIMP测年的年龄为141.56±0.96 Ma,应归属于早白垩世。盆地粗面岩具有钾含量高,全碱含量高,稀土元素配分曲线图表现为右倾的轻稀土富集型,Eu负异常不明显或表现为正异常的特征,表明三百山盆地的粗面岩属橄榄玄粗岩系列,具有高压型粗面岩的特征,标志着一个加厚的陆壳存在;岩浆物质来源于由上地壳物质俯冲到深部与地幔的混合而形成的再循环富集地幔,岩石形成的构造环境为＂同碰撞＂环境,代表挤压至拉张过渡构造环境。     

Influence of Ice and Snow Sports Participation Experience on Participation Constraints among Residents in Southern China: A Quantitative Analysis based on Propensity Score Matching

Under the initiative of “encouraging 300 million people to participate in ice and snow sports” and the guidance of the ‘Evidence-based’ policy-making process, this study takes the Hierarchical Model of Leisure Constraints as the theoretical framework to empirically explore the constraints influencing the participation of residents in Southern China in ice and snow sports. After factor analysis, the constraint dimension of residents’ participation was obtained, and the constraints of participants and non-participants were evaluated and compared by Propensity Score Matching (PSM). The results indicate that Chengdu residents have potential interest in and demand for winter sports, and the constraint dimensions are: facilities and services, companions, time, and personal feelings. The predisposition scores of the experimental group and the control group revealed that the constraints on interest, relevant knowledge and skills, and personal feelings of the participating group were significantly lower than those of the non-participating group, while the other constraints were not significant. We suggest that efforts should be made to increase the effective supply according to local conditions in order to reduce structural constraints, and the social attributes should be integrated into ice and snow sports to resolve the inter-personal constraints.     

Land use structure optimization under systematic framework

This paper puts forward the concept of land use structure optimization under space-time coupling through analyzing the systematic characteristic of land use structure optimization. It mainly expounds the construction of land use structure optimization model at different levels. Lastly, this paper explains the practicableness of land use structure optimization under systematic framework through the example of Qionghai city.     

Choice set formation with multiple flexible activities under space–time constraints

In classical time geography, an individual travel path is composed of a chain of visits, with each visit being a flexible activity between two fixed activities at two known stations. In reality, individuals tend to carry out trips with much variation and complexity, with multipurpose trips being a prominent and pervasive phenomenon. There is limited research to date on multipurpose trips in time-geographic analysis by geographic information system (GIS) scientists, or more specifically, multiple flexible activities between two fixed stations. To fill this gap, this article proposes four models for identifying the choice set with multiple flexible activities under space–time constraints. The models are derived through set-theoretic formalism based on the concept of trip chaining. The structure of the four models establishes a theoretical framework for conceptualizing trip-chaining behaviour with respect to the fixity of activities and the number of fixed stations as destinations or origins. They provide fundamental and rigorous apparatus for studying complex individual activity–travel patterns in many applied contexts when multipurpose trips are involved. This article also describes implementation of the models with a real transportation network as a way of validation.     

滇西崇山剪切带南段左行走滑作用的构造特征及时代约束

作为保山地块与兰坪-思茅盆地的重要边界,崇山剪切带新生代以来经历了多阶段的构造变形;其中以大规模走滑韧性剪切作用最为明显,表现为北段以右行走滑剪切为主、南段以左行走滑剪切为主.本文通过对崇山剪切带南段永保桥-瓦窑桥剖面出露的崇山群石英片岩、片麻岩及糜棱岩等进行详细露头解析、室内显微构造观察以及变形石英的EBSD组构分析,认为崇山剪切带南段的岩石新生代以来至少经历了两期不同环境下的韧性变形:第一期(D1)为纯剪条件下的收缩变形,发生的温度条件大约在550 ～ 650℃(角闪岩相),表现为一些褶皱构造、石香肠或透镜体构造的发育及石英的C轴组构图呈斜方对称式;第二期(D2)为单剪递进条件下的左行走滑剪切变形,表现形式为走滑剪切面理的发育及各类岩石遭受韧性剪切变形从而改造成糜棱岩.此外,在崇山剪切带内发育一套含电气石花岗质脉体,根据详细的露头解析及显微构造分析,本文认为该套含电气石花岗质脉体是左行剪切作用初期阶段伴随的深熔作用的产物,为同剪切花岗岩脉.本文选取了两个含电气石花岗质脉体的样品进行了LA-ICP-MS锆石U-Pb测年,分别得到21.7±0.3Ma和22.7±0.3Ma的锆石U-Pb年龄,进一步表明了崇山剪切带南段的左行剪切作用起始时代在22Ma左右或略早于22Ma.