Showing papers by "Sun Yat-sen University published in 1981"
TL;DR: The Kriging interpolation showed that the spatial variation of Guangzhou UHI was closely correlated with underlying surface, man-made heat, atmospheric pollutant and weather system, and the analysis on the temporal variation from January 2001 to February 2002 revealed that there were multi-scale UHI periods.
Abstract: Hourly data were collected from 47 automatic weather stations in Guangzhou to calculate the Guangzhou urban heat island (UHI) intensity in January, April, July and October 2001. The Kriging interpolation showed that the spatial variation of Guangzhou UHI was closely correlated with underlying surface, man-made heat, atmospheric pollutant and weather system, and the analysis on the temporal variation from January 2001 to February 2002 by Morlet wavelet transform revealed that there were multi-scale UHI periods. The main time scales were daily, weekly and bimonthly periods, and the secondary time scale was trimestral period. Sea-land breeze, man-made heat, long wave radiation of earth surface, and heat exchanges on earth surface affected the daily period, human activities affected the weekly period, solar radiation and weather system affected the bimonthly, period, while monsoon affected the trimestral period. This temporal-spatial variation of Guangzhou urban heat island was deeply affected by the coactions of weather system, long wave radiation, underlying surface, atmospheric pollutant, man-made heat, and heat exchanges on earth surface, etc.
11 citations
TL;DR: In this paper, the ratio between spontaneous polarizations of a and c domains in the original BaTiO3 single crystal is determined, rather than integration with a capacitor, and the hysteresis loops obtained by the two methods are compared.
Abstract: Rather than integration with a capacitor, digital computation methods are applied to ferroelectrics, and the hysteresis loops obtained by the two methods are compared. The computational method is more accurate, and provides more information regarding the structure and motion of domains. The ratio between spontaneous polarizations of a and c domains in the original BaTiO3 single crystal is determined. Digital integrational methods are also applied to the measurements of pyroelectric and piezoelectric constants.
1 citations
TL;DR: In this article, the linear and nonlinear effects of the polarization process in KDP type crystals are discussed by the method of N + 1 time Green's functions based upon the model of a coupling of the lattice with the proton system described as a four sublattice.
Abstract: The linear and nonlinear effects of the polarization process in KDP type crystals are discussed by the method of N + 1 time Green's functions based upon the model of a coupling of the lattice with the proton system described as a four sublattice. The second-rank, third-rank, fourth-rank susceptibility tensors are derived.