The paper summarizes research history and forming process of air negative ion, and how to increase air negative ion to improve city environment.
综述了空气负离子的研究历史、产生过程以及增加空气负离子改善城市环境的措施。
Before introduce the new model, this paper reviews the research history and research findings of city formation and rank-size distribution of cities firstly.
在建立的自己的模型之前，本文首先回顾了有关城市形成和城市位序规模分布的研究历程和研究成果。
It has been 90 years' history since the research articles issued by Auerbach in 1913 sparked the study of city size distribution.
自1913年奥尔巴赫发表的对城市规模分布的研究文章掀起了对城市规模分布的热潮以来，至今已有九十年的历史。
Unearthing and studying Zhengzhou city and Yanshi city of Shang dynasty were an important research result in the Chinese archaeological history in the 20th century.
郑州商城与偃师商城考古发掘研究，是20世纪中国考古史上的重大科研成果。
As a cultural city with long history, Chengdu has attracted interest of many experts and scholars, who achieved some research results.
成都作为一个历史文化名城，曾经引起当代许多专家学者的兴趣，并形成了一些颇有价值的成果。
As a cultural city with long history, Chengdu has attracted interest of many experts and scholars, who achieved some research results.
成都作为一个历史文化名城，曾经引起当代许多专家学者的兴趣，并形成了一些颇有价值的成果。
应用推荐