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Impact of Urban Village on Job-Housing Balance in Shenzhen: A Study Using Mobile Phone Signaling Data
TONG De, GAO Jing, GONG Yongxi
Acta Scientiarum Naturalium Universitatis Pekinensis    2020, 56 (6): 1091-1101.   DOI: 10.13209/j.0479-8023.2020.069
Abstract989)   HTML    PDF(pc) (1330KB)(265)       Save
Taking Shenzhen as an example and TAZ (traffic analysis zone) as the research unit, by means of multiple linear regression and spatial lag model, using mobile phone signaling data, urban built environment data and so on, the role of urban village in promoting job-housing balance is revealed under the premise of controlling the influence of variables such as built environment on the commuting distance. Main conclusions are as follows. Firstly, the average commuting distance of TAZ with a high proportion of urban villages is relatively short and the existence of urban village is favorable to promote job-housing balance, which is related to the large scale, scattered distribution, low rent, flexible lease period and low income of the tenants of urban villages in Shenzhen. Secondly, built environment also has significant influence on average commuting distance of residents. Increasing the degree of land use mixing, increasing the diversity of built environment, optimizing public transportation and destination accessibility will reduce the average commuting distance of TAZ residents in varying degrees and the average commuting distance of residents in TAZ with good social and economic environment is longer. Thirdly, the commuting distance of residents has obvious spatial autocorrelation.
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Storage of Water in Inorganic Salt Hydrates and the Implications to Latent Heat in Phase Changes
ZHAN Jia, QIN Shan, GAO Jing
Acta Scientiarum Naturalium Universitatis Pekinensis    2018, 54 (1): 80-86.   DOI: 10.13209/j.0479-8023.2017.070
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The dehydration processes of three selected inorganic salt hydrates, CuSO4·5H2O, Na2HPO4·12H2O and Na2SO4·10H2O, were respectively investigated to obtain the influence of water on the latent heat. Simultaneous DSC (differential scanning calorimetry)-TG (thermogravimetry) combined with Raman spectroscopy were employed to monitored the dehydration processes and the structural variations. The result reveals that for those salt hydrates which dehydrate mainly crystal water at melting point, the role of water in the structure directly influences not merely the thermal effect but the latent heat. For most salt hydrates, the water content exhibits a negative correlation with the latent heat for per mole water. Na2HPO4·12H2O melts to a salt hydrate with fewer moles of water, whereas Na2SO4·10H2O melts to its anhydrous form. Previous studies claim that there exists a quantitative relationship between the latent heat of salt hydrate and the number of crystal water. However, the comparison of the dehydration processes of Na2HPO4·12H2O and Na2SO4·10H2O indicates that whether this conclusion is generally applicable needs further study.

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