title: The effect of geographical proximity on scientific cooperation among Chinese cities from 1990 to 2010.
abstract: BACKGROUND
  The relations between geographical proximity and spatial distance constitute a popular topic of concern. Thus, how geographical proximity affects scientific cooperation, and whether geographically proximate scientific cooperation activities in fact exhibit geographic scale features should be investigated.
  
  
  METHODS
  Selected statistics from the ISI database on cooperatively authored papers, the authors of which resided in 60 typical cites in China, and which were published in the years 1990, 1995, 2000, 2005, and 2010, were used to establish matrices of geographic distance and cooperation levels between cities. By constructing a distance-cooperation model, the degree of scientific cooperation based on spatial distance was calculated. The relationship between geographical proximity and scientific cooperation, as well as changes in that relationship, was explored using the fitting function.
  
  
  RESULTS
  (1) Instead of declining, the role of geographical proximity in inter-city scientific cooperation has increased gradually but significantly with the popularization of telecommunication technologies; (2) the relationship between geographical proximity and scientific cooperation has not followed a perfect declining curve, and at certain spatial scales, the distance-decay regularity does not work; (3) the Chinese scientific cooperation network gathers around different regional center cities, showing a trend towards a regional network; within this cooperation network the amount of inter-city cooperation occurring at close range increased greatly.
  
  
  CONCLUSIONS
  The relationship between inter-city geographical distance and scientific cooperation has been enhanced and strengthened over time.
authors.affiliation: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Ma
authors.affiliation: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Chuanglin
authors.initials: C
authors.lastname: Fang
authors.affiliation: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Pang
authors.affiliation: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
authors.forename: Guangdong
authors.initials: G
authors.lastname: Li
mesh_terms: D002681:China; D006801:Humans; D012586:Science; D014506:Urban Renewal; D014507:Urbanization