Beginning in the 1950s, municipal governments and state-owned enterprises built socialist welfare housing estates. When the 1990s arrived, these agencies sold many of these same estates to the sitting tenants. Although the welfare system has changed, these pre-reform housing estates have become important in the urban environment and housing market. This paper examines their physical condition, the socio-economic profiles of their residents, and how these residents view their estates. The respective research questions are: What are the physical conditions of the pre-reform housing estates? Who lives in these estates? What are their opinions of their housing and of their estate communities? The research focuses on the Yangtze River Delta region, reporting on fieldwork in four housing estates still occupied by the original tenants. Data comes from a survey of 217 households as well as in-depth interviews. The findings reveal that most residents are older with low income. Although their housing is poorly maintained and managed, most prefer to continue living in their estate. These results suggest the central government should give local authorities autonomy regarding the renewal and maintenance pre-reform socialist welfare housing and local authorities need to take definite steps to improve the estate communities within their jurisdiction.
Strengthening the transmission uniformity of remedial amendments in heterogeneous porous media is important for improving in situ groundwater remediation efficiency. This study developed a characterization method to represent the improvement of transmission uniformity in heterogeneous media using the degree of difference in hydraulic conductivity of porous media between xanthan solution and pure water, which was defined as the transmission uniformity control coefficient U. Research results showed that U of medium sand/fine sand (2.44) was the most ideal among the three medium combinations tested when the concentration of xanthan solution was 100 mg/L. Then, factors that may influence U were analyzed, and the obtained results showed that xanthan’s control ability is affected by permeability contrast (media combinations) and polymer concentration. Generally, when concentrations were in the range of 100~800 mg/L, Umf > Ucf > Ucm. Finally, the actual degree of polymer propulsion under different concentrations and media combinations was analyzed, and the obtained results showed that as different media were varied in permeability change degree, while the migration speed presented an overall decrease as the concentration increased, where the maximum migration front in the low-permeability zone (LPZ) was more obvious than that in the high permeability zone (HPZ). This was consistent with the results characterized by U.
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