非洲粮食问题的时空演化研究

非洲粮食生产与发展面临着诸多的困难与挑战,其粮食问题一直是国际社会关注的热点之一。本文研究的非洲粮食问题主要是指其粮食生产、消费及其自给能力方面存在的问题,从时间与空间视角对非洲粮食此类问题的演化过程和成因进行了初步探讨。时间视角上,考虑到20世纪90年代中期到21世纪初期非洲粮食问题表现较为典型,同时限于相关数据获取因素故,仅研究了1994-2007年,非洲粮食生产量、粮食消费量及生产性粮食缺口量的演化;空间视角上,从整体与区域两个层面,探讨了非洲不同粮食自给类型国家的空间差异及演化。最后提出解决非洲粮食问题的相关对策与建议。     

中国崛起的国际地缘战略研究

围堵与反围堵是世界历史上大国崛起的常态。本文立足于结构现实主义的国际关系原理,运用地理学的空间相互作用和区位选择等理论,探讨中国在和平崛起过程中权力一利益半径外延的必然性、与本文为竞争利益空间而发生的全球性战略互动,以及由此诱发的周边地缘风险。作者指出,由于区域的非均质性,中国向外实现战略突破时只能依循非均衡路径,即集中优势资源在空间阻滞效应较弱、"投资"回报较高的局部地区率先实现突破,并以此为"极轴"向其他地区辐射战略影响。在全球层面上,由于综合国力的结构性缺陷,目前中国宜把战略资源优先投放到"低政治"领域,运用渗透性较强的经济手段,争取尽快在非洲、拉美与西欧等地获取必要的战略立足点;而在区域层面上,中国应追求在"高政治"领域有所建树,选择与中国在地理上接近、文化亲缘性较强、战略互信度较高的国家进行对外拓展,如:巴基斯坦、缅甸、蒙古、塔吉克斯坦和哈萨克斯坦等地。两者相辅相成,共同组成了21世纪中国和平崛起的国际地缘战略。     

南海问题的大周边地缘环境

南海的西沙、南沙等历来是中国的领土,但如今海洋国土存在重大争议,南海已经成为世界上最复杂、最紧张的水域之一,南海周边的政治、军事、经济地缘环境也越来越为复杂。本文以南海问题为切入点,基于南海地理区位中的要素联系对南海周边国家的地缘环境进行探讨。结果得出:南海问题是涉及多元利益和跨国机构关联的复杂问题,南海周边是一个包含域内争端国家、域外干涉国家和具有复杂组织机构关联的"大"周边,南海周边地缘环境是超出地理毗邻的"大"地缘环境,中国南海的维权维稳势必要在域内双边地缘环境、域外多边地缘环境、国际多元多边地缘环境等构成的大周边地缘环境下做出战略决策。     

车尔臣河下游生态恢复的成因初步分析

利用且末1958--2005年的降水、气温、径流量、卫星遥感等资料,分析了车尔臣河下游生态环境变化的成因。指出全球气候变暖使得山区冰川融解加快,车尔臣河径流量增加有利于车尔臣河下游生态恢复;人类活动的增加如修防渗渠、人工造林、人工增雨、围湖育苇、人工输水等活动改变了小气候,改善了绿洲生态环境,是车尔臣河下游生态环境恢复的主要原因。     

A GIS Approach to Exploring Monetary Value on Enclosure Era Property-Related Maps

Historical enclosure era property-related maps can tell us a great deal about the life and times of communities in the past. This study offers a unique approach to studying the historical landscape by applying GIS techniques to the examination of an eighteenth-century English village. Using novel GIS applications relying on historical maps, the study explores various aspects of the village’s physical and social characteristics. In doing so, the study forges effective linkages between cultural and landscape variables to reveal aspects of the historical landscape in eighteenth-century Britain previously inaccessible to researchers. This, in turn, provides a much more comprehensive and sophisticated template for future use by historical geographers in a number of contexts.     

Discovering spatial and temporal patterns from taxi-based Floating Car Data: a case study from Nanjing

Floating Car Data (FCD) refers to the trajectories of vehicles equipped with Global Positioning System-enabled devices that automatically record location-related data within a short time interval. As taxies in Chinese cities continually drive along the streets seeking passengers, FCD can easily traverse the entire street network in a city on a daily basis. Taking advantage of this situation, this study extracted passenger pickup and drop-off locations from FCD sourced from 6445 taxis over a 2-week period in Nanjing, China to discover human behavioral patterns and the dynamics behind them. In this study, road nodes are converted to the points, based on which Thiessen polygons are generated to divide the study area into small areas with the goal of exploring the spatial distribution of pickup and drop-off locations. Moran’s I index is used to calculate the spatial autocorrelation of the spatial distribution of pickup and drop-off locations, and hot spot analysis is used to identify statistically significant spatial clusters of hot and cold spots. The spatial and temporal patterns of FCD in the study area are investigated, and the results show that: (1) the temporal patterns show a strong daily rhythm, (2) the spatial patterns show that the number of pickup and drop-off locations gradually diminish from the downtown areas to the outer suburbs, (3) the spatiotemporal patterns exhibit large differences over time, and (4) the driving forces explored by regression models indicate that population density and transportation density are consistent with the population distribution, but per capita disposable income is not consistent with the population distribution.     

超高层建筑平面控制网竖向传递实践与研究

分析了超高层建筑平面控制网的建立及竖向传递的方法,介绍了数字正垂在测定超高层建筑倾斜偏差的具体应用,实现了用全站仪法和GPS法来检核控制网竖向传递的精度。     

广安市城市扩展变化的遥感监测动态分析

我国正处于工业化、城镇化快速发展时期,建设用地供需矛盾十分突出。采用3S集成技术,分析广安区在本世纪前7年的城市扩展的变化特征。结果表明,广安区在这7年中发展非常迅速,自然环境与交通在其扩展过程中起到了重要的作用。     

张衡地动仪（1）：诞生的历史

The emergence of Zhang Heng＇s seismoscope has a profound historical background. This paper intends to explore the formation and material basis of Zhang Heng＇s scientific thought. It appears that the simple intention of ＂observing visions and distinguishing good fortune or misfortune＂ was his motivation to develop the seismoscope. Tracing its historical background, the authors proposed in this paper that the development of this seismoscope started around 128 A.D., and based on perceptual knowledge, two ideas about earthquakes came into being, i. e. , earthquake location could be judged according to the instrument shaking direction, and the earthquake and earth split were essentially different. In the instrument manufacture, Zhang Heng advocated a principle of ＂making utensils to imitate cosmos ＂. By this principle, the following three problems were readily solved： the seismoscope imitated the response of the suspension system to earthquakes （ i.e. natural seismoscope） . Technically, the trigger mechanism of the latch was used for reference, and it recorded the physical evidence of earthquake occurrence by an ingenious way of a ball dropping from a dragon＇s mouth. The solution of these three key problems lead to the emergence of the seismoscope in 132 A.D. and the successful detection of an earthquake in 134 A.D. His invention deepened humanity＇s knowledge of natural laws, and promoted the development of science and technology in that time and later.     

永安地震台数字地震观测系统常见故障的分析及排除

论述了永安地震台数字地震观测系统的组成单元及各单元的作用与功能,总结、分析日常观测中常见的各类故障,并详细分析仪器运行过程中典型故障的产生原因及排除方法,可为其他相关地震台站提供借鉴。