Study on soil-water characteristic curves in the profiles of collapsing walls of typical granite Benggang in southeast China.

Benggang with steep collapsing walls is one of the worst soil erosion problems in South China. The collapse of walls is the most critical process in Benggang development. This is mainly due to the soil water properties. The soil water characteristic curve (SWCC) is a key indicator for analyzing soil moisture, but the SWCC and its mechanism of influence in collapsing walls remain obscure. A pressure plate meter was used for drying experiments to research the SWCCs of undisturbed soils of five layers (from top to bottom: red soil layer, transition layer I, sand soil layer, transition layer II and detrital layer) of two typical collapsing walls. The van Genuchten (VG) model can be fitted to the SWCCs for different layers (NSE ≥ 0.90). With increasing soil depth, the parameters a and θ s first decreased and then increased, the parameters n first increased and then decreased, θ r declined as the soil depth increased. These findings illustrate that soil water holding capacity decreases with increasing soil depth. The bottom of the soil is weak in water retention and water can easily reach saturation, resulting in a decline in soil stability, thus promoting soil collapse and finally inducing upper soil collapse. Furthermore, gravel content and particle morphology are factors that should not be neglected for SWCCs. The results of this study provide a theoretical basis for understanding the process of wall collapse in Benggang landforms in South China.

Engineering optical emission in sub-diffraction hyperbolic metamaterial resonators.

Sub-diffraction hyperbolic metamaterial resonators are promising structures for engineering light-matter interactions in semiconductor-based emitters and materials. The optical properties of these resonators are determined by a number of device characteristics including the metamaterial permittivity and resonator geometry. In this letter, we develop an optical model based on the modified long wavelength approximation to calculate the radiative and non-radiative photon loss of the resonators. We fabricate and characterize 11 different resonator arrays to demonstrate the effectiveness of model. Using the model, we demonstrate how the radiative properties of the resonators can be engineered via the design of the semiconductor metamaterial and the aspect ratio of the resonator. Over the explored design space, we demonstrate an eightfold increase in the radiative rate compared to the non-radiative rate. Our work reduces the complexity of designing sub-diffraction hyperbolic metamaterial resonators, allowing broader incorporation of these optical structures into novel devices and materials.

Human rabies epidemiology in Shandong Province, China.

Rabies has reemerged in China. National rabies surveillance is centralized and based mainly on six provincial stations, including one in Shandong Province, which are selected and monitored by the China CDC. Data collection includes human rabies cases (diagnosed by local hospitals on the basis of signs or symptoms), documentation of post-exposure prophylaxis, primary laboratory diagnosis of suspect animal cases, and investigation of dog or other animal bites in viral transmission. Of the 408 human rabies cases reported during the period 2003-2007, most involved middle-aged male farmers bitten by their own unvaccinated dogs, with a seasonal peak in the autumn. These data provide key pointers regarding rabies prevention and control based upon an objective evidence-based framework.