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The relation between the household electrical consumption Y and population N for Chinese cities in 2006 has been investigated with the power law scaling form Y = A0N β. It is found that the Chinese cities should be divided into three categories characterized by different scaling exponent β. The first category, which includes the biggest and coastal cities(More)
We have theoretically investigated the reflectivity spectrums of single- and double-layer photonic crystal slabs and the dielectric multilayer stack. It is shown that light can be perfectly confined in a single-layer photonic crystal slab at a given incident angle by changing the thickness, permittivity or hole radius of the structure. With a tunable(More)
Periodic segregation behaviors in fine mixtures of copper and alumina particles, including both percolation and eruption stages, are experimentally investigated by varying the ambient air pressure and vibrational acceleration. For the cases with moderate air pressure, the heaping profile of the granular bed keeps symmetrical in the whole periodic(More)
We experimentally investigate a discharging flux of granular particles through a sieve plate subject to vertical vibrations. The mean mass flux shows a non-monotonic relation with the vibration strength. High-speed photography reveals that two stages, the free flight of the particles' bulk over the plate and the adhesion of the particles' bulk with the(More)
Based on the physical optics (PO) theory, the radar cross section (RCS) of a metal sphere is numerically calculated and analyzed at high frequency limits in the Terahertz region. To obtain the relation between RCS and frequency, the scattered electric fields are estimated by using the integral equations under far field approximations for various beam widths(More)
To overcome the competition between the side lobe suppression and the main lobe spread in radar imaging, we introduce a super-resolution imaging algorithm based on the iterative processes of the reshaped window function. The side lobes of the target imaging are sensitively dependent on the structures of reshaped window function, and the main lobes, however,(More)
We have investigated the population distribution of Chinese cities from 1997 to 2006. The rank-size distributions of Chinese cities deviate from the Pareto distribution. For city size distribution of each year we can find a population threshold Pc that characterizes the boundary of the deviation. The cities with population more than Pc follow the Pareto(More)
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