乡村振兴视角下秦巴山区农村路网通达性评价与分区优化研究——以陕西省山阳县为例

交通是经济发展的命脉,路网通达性是衡量交通发展水平的有效评价指标。以位于秦巴山区的陕西省山阳县为例,采用网络分析、空间自相关与地理加权回归等方法,从分项评价、综合评价两方面研究农村路网通达性,并进行通达性分区;提取各区中对经济发展影响较大的分项因子,有针对性地提出了优化策略。结果表明:(1)山阳县路网通达性呈北高南低、由高通达性极核向外围递减的"核心—外围"空间分异特征。(2)通达性水平高的区域地形平坦,区内外交通条件优良,是山阳县的经济、政治及文化中心,对周边村镇有一定辐射带动作用。通达性水平低的区域区位偏远,地形复杂,经济发展滞后。(3)路网通达性水平与社会经济的相关系数在不同分区有空间异质性。最后,提出分区优化建议,以促进经济发展,助力乡村振兴。     

Eoshumardia (Trilobita,Cambrian), a junior synonym of Koldinioidia

Well-preserved internal and external moulds of a shumardiid species are described from the late Furongian (Late Cambrian) “Fengshan Formation” at Poben, Napo, southwestern Guangxi, which is close to the type locality of Shumardia orientalis, the type species of Eoshumardia. All features observed on the internal moulds indicate that the new material is definitely S. orientalis, whereas the morphology of the external moulds indicates that S. orientalis should be referred to Koldinioidia. The change of generic assignment of the type species means that Eoshumardia is a junior synonym of Koldinioidia.     

中国近代城市警政区划研究

城市警政区划是城市中警务区域的划分,是地方公安组织设置的空间基础,也是警察行为的空间体现,反映了公安机构与城市环境之间的关系.中国近代城市警政区划在1898至1949年间,划分原则与城市发展的互动关系各有阶段特征.本文通过划分清末早期建警时期、清末巡警部时期、北洋政府时期和南京国民政府时期四个阶段,对各阶段城市警政区划的演变脉络进行梳理,重点探讨其划分依据、结构特征和与城市发展之间的互动关系,最终总结中国近代城市警政区划的演变规律.     

Bleached mudstone,iron concretions,and calcite veins: a natural analogue for the effects of reducing CO2‐bearing fluids on migration and mineralization of iron,sealing properties,and composition of mudstone cap rocks

This study investigates the Wangfu Depression of the Songliao Basin, China, as a natural analogue site for Fe migration (bleaching) and mineralization (formation of iron concretions) caused by reducing CO₂‐bearing fluids that leak along fractures after carbon capture, utilization, and storage. We also examined the origin of fracture‐filling calcite veins, the properties of self‐sealing fluids, the influence of fluids on the compositions of mudstone and established a bleaching model for the study area. Our results show that iron concretions are the oxidative products of precursor minerals (pyrite and siderite) during uplift and are linked to H₂S and CO₂ present in early stage fluids. The precipitation of calcite veins is the result of CO₂ degassing and is related to CO₂, CH₄, and minor heavy hydrocarbons in the main bleaching fluids. In our model, fluids preferentially enter high‐permeability fracture systems and result in the bleaching of surrounding rocks and precipitation of calcite veins. The infilling of calcite veins significantly decreases the permeability of fractures and forces the fluids to slowly enter and bleach the mudstone rocks. The Fe²⁺ released during bleaching migrates to elsewhere with the solutions or is reprecipitated in the calcite veins and iron concretions. The formation of calcite veins reduces the fracture space and effectively prevents fluid flow. The fluids have an insignificant effect on minerals within the mudstone. In terms of the chemistry of the mudstone, only the contents of Fe₂O₃, U, and Mo change significantly, with the content of U increasing in the mudstone and the contents of Fe₂O₃ and Mo decreasing during bleaching.     

建筑与土木工程领域全日制硕士研究生实践教学质量评价指标体系研究

为提升建筑与土木工程领域全日制专业学位硕士研究生实践教学质量,构建了一套实践教学质量评价指标体系。针对武汉理工大学建筑与土木工程领域全日制专业学位硕士研究生实践教学特点,运用层次分析法确定指标权重,采用灰色聚类法评价实践教学质量,确定等级。实证研究显示:实习基地建设是实践教学的薄弱环节,该研究为进一步提高实践教学质量指明了努力方向。     

基于环境犯罪学理论的入室盗窃时空分布研究——以北京市主城区案件的分析为例

以往关于犯罪时空特征的研究较多的侧重于对犯罪时空分布现象的描述分析以及从人文地理视角下的环境影响性分析,但缺少从环境要素与犯罪主体行为之间的相互作用机制下的犯罪时空特征研究。本文通过开展北京市入室盗窃案件的时空热点实证分析,总结和归纳了案件热点环境的时空要素类型,并基于环境犯罪学的基本原理,构建了基于犯罪主体与环境影响要素相互作用的犯罪时空分布机制,其中,环境对犯罪主体的影响主要表现为四类要素,即目标、交通、防范和作案时机。这些研究可以为下一步开展犯罪模拟以及犯罪预防提供借鉴。     

Child loss and maternal wages in China

Using data from a random sample of the 2005 National Population Survey of China, we investigate the association between child death and maternal hourly wages. Approximately 1.6 per cent of the population has experienced at least one child death. Such bereaved mothers’ hourly wages are 53 per cent lower than those of non-bereaved mothers. We find that child death carries a significant wage penalty. Son death has a larger impact than daughter death and its effect decreases as the number of children in the household increases. Our decomposition results show that number of children, maternal education and regional characteristics are the three most important contributors to the wage gap, yet unexplained differences remain large, especially at the lower end of the wage distribution.     

滇黔桂省际边界区域城镇经济联系的网络结构特征与演化分析

以滇黔桂省际边界区域28个城镇为例,构建城镇中心性评价指标体系,利用改进的熵值法测度各城镇的中心性得分,评价滇黔桂省际边界区域经济空间结构演变,利用修正的引力模型测度了1995年、2004年、2014年3个年份各城镇之间经济联系强度;借助GIS技术手段分析了城镇经济联系强度的空间格局,评价城镇等级体系演化特征;最后利用社会网络分析方法考察了城镇经济空间联系和网络关系的演化规律,得出如下结论：滇黔桂省际边界区域中心城市逐渐形成,经济重心由南向北转移,由右江区单中心逐步发展到兴义市、右江区、文山市三中心,再到兴义市发展成为强中心,平果县与靖西市具备发展为滇黔桂次中心城镇的潜力;城镇间的经济联系总体较弱,区域整体网络密度低,但呈现出不断增强的趋势,低等级城镇对高等级城镇的引力与高等级城镇对低等级城市的引力不同,形成两种不同的城镇网络体系,经济联系紧密地区主要集中在中心城市之间及中心城市与经济强县之间;三角结构的外围经济联系密度明显较低,对于大多数城镇来说,尚不具备经济辐射能力,辐射效应极弱。     

Asynchronous,Iterative, and Parallel Procedures for Solving the Weighted-Region Least Cost Path Problem

A family of local, asynchronous, iterative, and parallel procedures (LAIPPs) are described. These procedures are designed to find least cost paths (LCPs) in bounded regions of the plane that have been partitioned into triangular subregions. The unit cost of traversing a given subregion is uniform within the subregion, but varies between subregions. In the case of one-dimensional chains of triangles, the procedures are guaranteed to converge to a global LCP. Although the procedures are guaranteed to terminate, we have so far been unable to prove, in the general case of a two-dimensional triangulation, that the procedures always terminate in admissible paths. Extensive experimental investigations, however, have revealed convergence to admissible paths in all cases examined. While counterexamples are constructed to prove that the procedures may converge to the local rather than global LCPs, convergence to the global LCP was found to occur in nearly all of our experimental investigations. The computational complexity of the procedures, as measured by the number of iterations required for convergence, was found experimentally to be independent of the size of the domain in which the paths lay, and to be slightly greater than linear in the Euclidian length of the paths. The complexity was also found to depend on the cost structure of the domain. Such LAIPPs appear to be promising procedures for both application and further investigation. In particular, the question of convergence is an interesting problem.     

周恩来与文物保护事业

周恩来一贯重视我国的文化建设事业 ,强调经济建设和文化建设必须同步地协调地发展。他在抓经济建设的同时 ,对我国的文化建设事业倾注了大量的心血 ;他十分重视保护和继承民族优秀文化遗产 ,他在指导文物保护方面所从事的卓有成效的工作和所阐述的深邃思想 ,对于继承祖国文化遗产起到了极其重要的作用 ;他利用一切可能的条件 ,发挥文物的作用 ,对我国的文物保护事业作出了不朽的贡献