都市农业加工型企业的发展机理与模式

都市农业是城市化进程中崭新的农业形态,但缺乏对其组织形式和生产方式的实证研究。本文基于对互润(国际)食品集团的调查实例,详细分析了都市农业加工型企业的成长机理,指出制度平台、政府行为和社区沟通是企业发展的外层机理,是企业平稳运行的基础;生产经营活动及其不断的扩张构成了企业发展的内层机理;创新和企业管理及市场的内、外部控制所形成的内核机理是企业发展的核心动力。据此,文章总结了都市农业加工型企业的发展模式,并就都市农业加工型企业如何发展提出了建议。     

广州城市空间结构与交通需求关系

在综述国内外相关研究的基础上,以广州为案例研究城市空间结构与交通需求的关系。结果表明,在城市形态与交通需求的关系方面,广州城市二维形态和三维形态与交通需求的空间分布之间具有一定的耦合性,二者存在一定互为因果的关系;交通方式的转化对城市形态的演化具有一定的驱动作用;城市形态引导着交通需求的总量和布局;同时,社会经济活动及其发展是城市形态与交通需求产生的原因和相互联系的纽带。在城市内部空间结构与交通需求的关系方面,模型分析表明,近年来广州城市内部居住与就业的空间均衡性增强,直接影响了交通需求的产生与分布和交通方式的选择,有利于居民就近选择就业,并使通勤交通的空间分布更加均衡;此外,居住与就业人口迁移先行,引导公共设施的发展也是近年来广州城市发展的主要特征之一;公共设施服务空间与交通需求之间存在需求作用型和供给作用型两种相互作用模式。     

城市居住-就业空间特征及组织模式——以广州市为例

作为城市居民生活与生产的两大载体,城市居住与就业用地及其空间组织对城市发展及空间格局起着重要的作用。随着中国城市社会经济和城市规划建设的发展,大城市居住-就业的空间格局发展巨大的变化。本文以广州为案例,分析了广州市居住-就业空间均衡性、宏观空间组织模式和不同片区的居住-就业中微观空间组织模式等,并从历史因素、政府因素、市场因素和社会因素等角度揭示了广州"自上而下"和"自下而上"两种力量共同作用下,居住-就业空间格局的演化过程和规律。论文倡导多元化的土地开发模式,提倡从居住与就业空间协调的角度调节交通需求的空间分布,进而优化城市空间结构,达到提高城市运作效率的目的,并试图在研究视角上为国内其他城市的同类研究提供借鉴。     

苏州城郊土地利用变化对土壤的影响

1IntroductionThe conversion of natural systems to agricultural production has been the primary basis for the successful growth of human populations for the last 9,000 years (Kates etal., 1990). The conflict between urban and agricultural land use, however…     

转型期广州大都市区户籍贫困人口特征和空间分布

20世纪90年代中后期以来,伴随着经济体制转型和国有企业改革的深化,广州市户籍贫困人口总量增加,贫困阶层种类由单一走向多元,新增种类中的下岗失业无业、在业低收入者成为救助对象主体.救助对象从基本没有收入的个体为主拓展到有少量收入的家庭为主,贫困深度降低.受到历史继承、单位制和工业企业改革、住房市场化和住房制度改革等因素的影响,户籍贫困人口区际空间分布和集聚的相对差异增加,贫困人口在内城外围区集聚程度明显增加,并在大都市区形成绝对改善区、相对缓解区、变化微小区、相对加重区和绝对加深区5种地域类型.对少数贫困     

NOx or VOC Limitation in East German Ozone Plumes?

The ozone forming potential of VOCs and NO_x for plumes observed from several cities and a power plant in eastern Germany was investigated. A closed box model with a gas phase photochemical reaction mechanism was employed to simulate several scenarios based upon aircraft observations. In several of the scenarios, the initial concentrations of NO_x, VOCs, and SO₂, were reduced to study the factors limiting the O₃ production. Ozone production was limited by the initial VOC concentrations for all of the simulated plumes. Higher O₃ concentrations were produced with reduced initial NO_x. In one sample with high SO₂ mixing ratios (>100 ppb), SO₂ was also identified as a significant contributor to the production of O₃.     

郑州市城市地理信息系统的总体设计

提出了建立郑州市城市地理信息系统的目标和原则,论述了系统的设计思想、总体结构、运行环境、功能和数据标准化等问题。     

CHARACTERISTICS OF ENVIRONMENTAL AND CLIMATE CHANGE IN CHANGJIANG DELTA AND ITS POSSIBLE MECHANISM*

Characteristics of climate change in the Changjiang Delta were analyzed based on the annual mean meteorological data since 1961,including air temperature,maximum and minimum air temperature,precipitation,sunshine duration and visibility at 48 stations in that area(southern Jiangsu and northern Zhejiang),and its adjacent areas(northern Jiangsu,eastern Anhui and southern Zhejiang),together with the environmental data.The results indicate that it is getting warmer in the Changjiang Delta and cooler in adjacent areas,thus the Changjiang Delta becomes a big heat island,containing many little heat islands consisting of central cities,in which Shanghai City is the strongest heat island.The intensity of heat islands enhances as economic development goes up.From the year 1978.the beginning year of reform and opening policy,to the year 1997,the intensity of big heat island of Changjiang Delta has increased 0.5℃ and Shanghai heat island increased 0.8℃.However.since 1978 the constituents of SO₂,NO_x and TSP(total suspended particles)in the atmosphere,no matter whether in the Changjiang Delta or in the adjacent areas,have all increased,but pH values of precipitation decreased.In the meantime,both sunshine duration and visibility are also decreased,indicating that there exists a mechanism for climate cooling in these areas.Our analyses show that the mechanism for climate warming in the Changjiang Delta may be associated with heating increase caused by,economic development and increasing energy consumption.It is estimated that up to 1997 the intensity of warming caused by this mechanism in the Changjiang Delta has reached 0.8-0.9℃,about 4-4.5 times as large as the mean values before 1978.Since then,the increase rate has become 0. 035℃/a for the Changjiang Delta.It has reached 1.3℃ for Shanghai in 1997,about 12-13 times as large as the mean values before 1978.This is a rough estimation of increasing energy consumption rate caused by economic development.     

城市建设用地与地质环境协调性评价的GIS方法及其应用

城市地质环境评价是城市规划和场地选址的基础 .以兰州市为例 ,以地理信息系统软件ARC/INFO为开发平台 ,建立了城市地质环境基础数据库 ,将城市用地类型分为高层建筑用地、多层建筑用地、低层建筑用地、垃圾填埋用地及自然保护用地 ,系统分析了各类用地与地质环境协调性评价的指标体系 ,采用层次分析法建立了评价模型 ,对不同的用地类型进行了评价 .结果表明GIS与评价模型的结合可以快捷、准确地进行城市建设用地与地质环境的协调性评价     

3D urban models: Recent developments in the digital modelling of urban environments in three-dimensions

This paper reports on recent developments in the visualisation of urban landscapes. There is a growing interest in the contstruction of 3D models of urban and built environment for which a host of digital mapping and rendering techniques are being developed. This paper extracts some of the cases that we came across during worldwide interviews carried out in March 2000. Building on this review, we identify the range of data and techniques adopted for the development of 3D contents and how they could contribute to geographical analysis and planning of urban environment. A particular focus is given on the effectiveness of GIS and its related methods for their capacity to accommodate the demands for visual representation of urban environment as well as the basis for analysis and simulation. This revised version was published online in July 2006 with corrections to the Cover Date.