China Three Gorges University

About: China Three Gorges University is a education organization based out in Yichang, China. It is known for research contribution in the topics: Catalysis & Landslide. The organization has 11161 authors who have published 8011 publications receiving 82224 citations. The organization is also known as: Sanxia Daxue.

On stationary patterns of a reaction–diffusion model with autocatalysis and saturation law

Abstract: Understanding of spatial and temporal behaviour of interacting species or reactants in ecological or chemical systems has become a central issue, and rigorously determining the formation of patterns in models from various mechanisms is of particular interest to applied mathematicians. In this paper, we study a bimolecular autocatalytic reaction–diffusion model with saturation law and are mainly concerned with the corresponding steady-state problem subject to the homogeneous Neumann boundary condition. In particular, we derive some results for the existence and non-existence of non-constant stationary solutions when the diffusion rate of a certain reactant is large or small. The existence of non-constant stationary solutions implies the possibility of pattern formation in this system. Our theoretical analysis shows that the diffusion rate of this reactant and the size of the reactor play decisive roles in leading to the formation of stationary patterns.

Doped, conductive SiO 2 nanoparticles for large microwave absorption.

Abstract: Although many materials have been studied for the purpose of microwave absorption, SiO2 has never been reported as a good candidate. In this study, we present for the first time that doped, microwave conductive SiO2 nanoparticles can possess an excellent microwave absorbing performance. A large microwave reflection loss (RL) of −55.09 dB can be obtained. The large microwave absorption originates mainly from electrical relaxation rather than the magnetic relaxation of the incoming microwave field. The electrical relaxation is attributed to a large electrical conductivity that is enabled by the incorporation of heterogeneous (N, C and Cl) atoms. The removal of the magnetic susceptibility only results in a negligible influence of the microwave absorption. In contrast, the removal of the heterogeneous atoms leads to a large decrease in the electrical conductivity and microwave absorption performance. Meanwhile, the microwave absorption characteristics can be largely adjusted with a change of the thickness, which provides large flexibility for various microwave absorption applications. Doped nanoparticles of silica (SiO2) have been found to act as a very strong absorber of microwave radiation. A US-Chinese collaboration of scientists discovered that, unlike pure SiO2 nanoparticles, those doped with atoms of N, C and Cl induce a reflection loss at large as −55 dB at a frequency of around 7 GHz. The doped nanoparticles, which measured 4–8 nm in diameter, were fabricated by slowly adding the precursor tetraethyl orthosilicate (TEOS) to the solvent N,N’-dimethylformamide (DMF) and then adding hydrazine monohydrochlorid. The resulting solution was then heated, washed and dried. The resulting nanoparticles were then dispersed in paraffin wax rings and the permittivity and permeability measured in the 1.0–18.0 GHz range using a network analyzer. The team attributes the strong microwave absorption to the doped nanoparticles’ good electrical conductivity.

Modeling of landslide generated impulsive waves considering complex topography in reservoir area

Abstract: The impulsive wave is considered as one of the most notably secondary hazards induced by landslides in reservoir areas. The impulsive wave with considerable wave amplitude is able to cause serious damage to the dam body, shoreline properties and lives. To investigate and predict the wave characteristics, many experimental studies employed the generalized channels rather than the realistic topography. Deviation from the idealized geometries may result in non-negligible effects due to the wave refraction or reflection with complex topography. To consider the topography effect, a prototype scaled experiment was conducted. A series of tests with different collocation of parameters were performed. The experimental results were then summarized to propose empirical equations to predict the maximum wave amplitude, and wave decay in channel direction. The generalized empirical equations can obtain better results for wave features prediction by compared with those derived from the idealized models. Furthermore, a 3D numerical modeling corresponding to the physical experiment was conducted based on the SPH method. The wave characteristics in the sliding and channel directions were investigated in detail including the maximum wave amplitude, wave run-up, wave arrival time and wave crest amplitude decay. The comparison between the simulation and experiment indicates the promising accuracy of the SPH simulation in determining the general features even with complex river topography. Finally, the limitation and applicability of both the experimental and numerical methods in analyzing the practical engineering problems were discussed. Combination of the both methods can benefit the hazard prevention and reduction for landslide generated impulsive waves in reservoir area.