地理信息系统支持下的中国粮食生产潜力研究

在地理信息系统（ＧＩＳ）及全国农业空间数据库和属性数据库的支持下,在前人关于农业生产潜力研究的基础上进行了全国粮食生产潜力的研究。作者首先论述粮食生产潜力研究进展,探讨了基于ＧＩＳ的粮食生产潜力研究方法;然后,就粮食生产潜力的土壤有效系数、土地生产潜力和社会有效系数、社会生产潜力提出了新型的计算模型,并应用机制法通过光、温、水、土、社逐级衰减,具体计算了全国分组粮食生产潜力;最后,针计算结果与实现     

京津冀地区与长三角地区制造业区域专业化特征分析

国内外有关区域专业化研究大多关于一个国家省区之间的专业化分工,对于一国之内经济区内部的区域专业化研究较少.然而,经济区内部分工是当前我国经济发展面临的热点问题,也是包括经济地理学在内的很多学科着力解释的重大议题.这里运用较为成熟的测度方法,以国家图书馆所能查到的最近的2003年各地市制造业分行业就业人口数据为数据源,测度描述区域专业化的区位基尼系数、区域专业化指数、区域分工指数等,综合全面地刻画"十一五"规划界定的京津冀地区和长三角地区区域专业化的行业特征和区域特征.另外,还比较了两个区域在专业化水平上的差异.     

长江三角洲地区门户功能演化与驱动机理

采用综合指数评价、基尼系数、标准差椭圆等方法分析了2004~2014年长江三角洲地区门户功能的空间格局及其演化过程。结果表明：① 长江三角洲地区城市门户功能上升趋势明显,空间上由“一极三强”的格局演变为“一极四强”;② 各类门户功能的空间差异整体上呈缩小趋势,其中国际门户功能的差异明显大于综合和国内门户功能,而组间差异是导致门户功能差异的主要原因;③ 所有门户功能均由南-北方向分布向东-西方向分布转型。长三角地区门户功能的演化是由多重因素驱动形成的,国内和国际门户功能的驱动机理存在明显差异。     

江苏省乡村经济类型的初步分析

本文采用模比系数法,按乡村经济发展水平、产业结构和农业结构三类指标,将江苏省65个县(县级市)划分为8个乡村经济类型(含12个亚类型),以便为乡村发展的宏观决策和分类指导提供参考,为开展江苏乡村地理的选点调查打下基础,对乡村经济类型的研究方法作初步尝试。     

Measuring the Spatial Focus of Migration Patterns

The changing territorial concentration of migration flows is of interest to many geographers, yet we still do not have a widely accepted index of spatial focus. The much used index of migration efficiency has been shown to be an inadequate index of such spatial concentration, and two candidates have been suggested to replace it: the Gini index and the coefficient of variation. Both are examined in this paper, and a comparative assessment is offered. Data from the 1970, 1980, and 1990 censuses are used to illustrate the two measures. An examination of the findings reveals that the coefficient of variation measure indicates higher levels of spatial focus than does the Gini index for states with highly concentrated flows.     

恒离子强度下KCl+K_2SO_4+H_2O溶液中氯化钾活度系数的测定

我们已用钾离子敏感膜电极和银—氯化银电极组成无液界电池,通过测量其电动势的方法测定了25℃时恒定离子强度(I=0.1,0.3,0.5和0.7)条件下,KCl—K_2SO_4水溶液中KCl的平均质量摩尔浓度活度系数。结果表明,KCl的平均活度系数的对数与混合溶液中每个电解质的离子强度分量,在该条件下服从哈内特线性关系。已用最小二乘法计算了相应的哈内特系数。在相应恒离子强度(I=0.1,0.3,0.5和0.7)条件下,其值分别为0.0430,0.0356,0.0329和0.0320。     

Experimental study on the coefficient of lateral pressure at rest for calcareous soils

Abstract

The coefficient of lateral pressure at rest (k₀) is a key parameter required to determine the horizontal stress distribution on subsoils. In this paper, k₀ was measured from consolidation test for calcareous and siliceous sand, and the effect of water contents on k₀ of calcareous sand was also discussed. Comparison of k₀ values measured and calculated based on empirical formulas were carried on. Results indicated that (1) the reduction rate of k₀ for calcareous sand with an increase in relative density was less than that of siliceous sand. The k₀ at low water content was generally smaller than that of siliceous sand, and it was similar to that of siliceous sand for high-water content; (2) the k₀ of calcareous sand increased with increasing initial water content initially, and then decreasing. However, the magnitude of variation was small. So the impact of water content on the k₀ of calcareous sand was limited; (3) the formulas proposed by Abdelhamid and Krizek (1976 Abdelhamid, M. S., and R. J. Krizek. 1976. At-Rest Lateral Earth Pressure of Consolidating Clay. Journal of the Geotechnical Engineering Division 102 (7): 721–738. [Google Scholar]) for estimation of the k₀ was highly applicable to calcareous fine sand.

• Highlights

• The k₀ of calcareous fine sand was investigated.

• The k₀ of calcareous and siliceous sand were compared.

• Shape parameters of sand particles for calcareous and siliceous sand were analyzed.

• Effects of related density and initial water content on the k₀ were discussed, respectively.

• The applicability of various empirical formulas for calculating k₀ of calcareous fine sand was evaluated.

     

Rural-urban spatial inequality in water and sanitation facilities in India: A cross-sectional study from household to national level

A major obstacle for the developing nations to meeting the United Nation's Sustainable Development Goals (SDG: 2015–2030) for WaSH (Water-Sanitation-Hygiene) is the appalling rural-urban inequality in infrastructural facilities that lead to regional/spatial differences in livelihood. In India, where about 70% of the population dwells in villages, rural-urban inequality can pose steep challenges to the authorities in their motto of ensuring improved water and sanitation for all. Cognizant of the need, the present study aimed to map nationwide rural-urban spatial inequalities for various WaSH infrastructural facilities along a four-tier administrative hierarchy: household-district-state-national. Cross-sectional data for district-wise percentages of rural and urban households having access to (i) latrine facility within premises, (ii) treated tap water, (iii) improved water source, and (iv) at-home water source were obtained from the Census of India database for 2011. A variety of metrices (Bray-Curtis Dissimilarity Index (BCDI), Gini coefficient, Moran’I, LISA) were used to characterize underlying spatial patterns. Rural-urban spatial inequality in 'treated tap water' appeared as the most spatially variable WaSH parameter across the nation. Results indicated that governmental claims of having met the Millennium Development Goal (MDG) for ‘improved’ water source require a thorough reappraisal, especially for rural India, as majority of these so called improved sources thrive on groundwater (hand pump+tube well), which is heavily contaminated by co-occurrences of multiple pollutants (fluoride, arsenic, nitrate, salinity), which have grave human health effects, and thus questioning the fundamental premise of 'safe water'. About 54% of the rural households in India rely on groundwater sources as compared to <20% urban households. In addition, about 67% of rural, against about 12% urban, households still ‘indulge’ in open defecation practices, which calls for stringent management actions coupled with strategic awareness campaigns. Rural-urban inequality in WaSH facilities appeared most alarming across the central Indian states of Chattisgarh, Bihar, Jharkhand, Odisha, Madhya Pradesh and Rajasthan. Overall, spatial heterogeneity in the rural-urban inequality appeared a daunting challenge for the authorities, urging for spatially-optimized policy reforms instead of enacting nationwide uniform policy measures.     

东北三省旅游经济质量的区域差异、动态演进及影响因素

采用SBM模型、Dagum基尼系数及分解方法、核密度估计法对东北三省36个城市旅游经济增长质量的区域差异及动态演进进行研究。结果表明：① 东北三省旅游经济增长质量总体水平不高,存在明显的区域差异;② 从差异来源及其贡献度来看,2007—2010年超变密度是地区差异的主要来源,2011—2018年地区间差异是差异的主要来源;③ 东北三省旅游经济质量总体核密度曲线逐渐向右移动,旅游经济质量水平不断提升,区域旅游经济差异逐渐减小;④ 旅游资源禀赋、生态环境和社会经济发展水平对旅游经济质量差异产生影响。     

博台线作为中国区域发展均衡线的佐证分析——以城市温室气体排放为例

国际政治经济形势正在发生深刻变化,实现区域协调均衡发展对于形成以国内大循环为主的新发展格局至关重要。方创琳于2020年2月提出垂直于胡焕庸线的博台线可以表征中国区域发展的均衡格局。本文通过对中国338个地级市的温室气体排放水平进行分析,旨在论证博台线作为中国区域发展均衡线的合理性和可能性。结果显示：① 2015年二氧化碳（CO₂）、甲烷（CH₄）、氧化亚氮（N₂O）和含氟温室气体总量以博台线为界呈南北对称的空间分布格局,且博台线两侧各类温室气体的排放强度和人均排放量分布基本均衡,各产业部门CO₂排放强度和人均排放量的区域差异均较小;② 博台线西南半壁和东北半壁内各类温室气体排放在GDP和人口维度上总体呈均衡分布态势,且各部门CO₂排放强度和人均排放量的空间分布也较为均衡。总体而言,博台线两侧表征人类活动强度的温室气体排放水平较为均衡,一定程度上反映出其作为中国区域发展战略均衡线的科学性与合理性。