Extraction of Basic Trends of Urban Expansion in China over Past 40 Years from Satellite Images

If urban sprawl is to be avoided in China in the next ten years, it is not only crucial to understand the overall history, current status, and future trends of urban expansion there, but also these differences, and this is presently lacking. In this study, remotely sensed images with approximately 30 m spatial resolution were used to quantitatively assess the spatial and temporal patterns of urban expansion of 60 Chinese cities(1973–2013). Urban-expansion-process curves of the cities studied were drawn using annual expansion area as an indicator. Curve similarity analysis generated four basic process modes of urban expansion in China. These included cities that: 1) peaked around 2004 and then decelerated; 2) peaked around 2010 and then decelerated; 3) showed sustained acceleration, and 4) showed continued deceleration. Four basic process modes represented cities under different levels of development stage. Geographic location was found to be the most related characteristic to urban expansion process. Regional development policies at the national level in each region also showed highly temporal consistency with fluctuation characteristics of urban expansion process. Urban characteristic such as population size and administrative level were not found to be significantly related to urban expansion-process modes. Understanding the basic process-mode categories well is extremely important for future regional-balance planning and development of macroeconomic policies.

Relationship between types of urban forest and PM_(2.5) capture at three growth stages of leaves

Particulate matter diameter ≤ 2.5 μm（PM2.5） causes direct harm to human health. Finding forms of urban forest systems that with the ability to reduce the amount of particulate matter in air effectively is the aim of this study. Five commonly cultivated kinds of urban forest types were studied in Beijing city at three stages of leaf growth. Results show that the urban forest system is capable of storing and capturing dust from the air. The types of shrubs and broadleaf trees that have the ability to capture PM2.5from the air are most effective when leaves have fully developed. In the leafless season, the conifer and mixed tree types are the most effective in removing dust from the air. For all kinds of forest types and stages of leaf growth, the PM2.5concentration is highest in the morning but lower in the afternoon and evening. Grassland cannot control particles suspended in the air,but can reduce dust pollution caused by dust from the ground blown by the wind back into the air.

The urban adaptation and adaptation process of urban migrant children: A qualitative study

This article employs qualitative research methods to explore the urban adaptation and adaptation processes of Chinese migrant children.Through twenty-one in-depth interviews with migrant children,the researchers discovered:The participant migrant children showed a fairly high level of adaptation to the city;their process of urban adaptation emerged as three categories:the U-Type,the J-type,and the“flat line”type.Also explored were long-term acquisition of explicit behaviors,implicit notions,adaptation to the socio-cultural environment,and success in education as difficult aspects of adaptation.After comparing these three processes,the research team developed a theory of migrant children urban adaptation.It hypothesizes that during the urban adaptation process,migrant children will encounter four stages of development:excitement and curiosity,shock and resistance,exploration and adaptation,and finally integration and assimilation.