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Abstract. Dust deposited on photovoltaic (PV) module surface is one of the most important factors that influence the power of PV modules. In this paper, the settling volume and distribution regularities of dust in the gas-solid two phase flow under different conditions of PV component installation angle and wind speed were respectively investigated by simulation. And compare the setting volume of simulation with the experiment results. The results indicate that low wind speed may make dust to deposit intensively on upper right of PV component surface with the constant installation angle. The bulk density of dust increases with increasing wind speed and stratification is more obvious. The faster wind speed is, the fewer the settling volume of dust it is. However, the deposition of dust on the surface show layered characteristics with the angle increased when the wind speed is faster. And the dust density of PV modules surface is reducing from edge to center resulting in homogeneous deposition of dust on PV component surface. Furthermore, the bigger installation angle is, the settling volume of dust more it is. And an angle of 45°is the max width of maximum bulk density area when inlet wind speed is constant.

Abstract. According to the satellite data provided by the US Renewable Energy Laboratory, the datum of solar resources 25 typical cities in China for 29 years were analysed by method of principal component analysis and the whole evaluation of this kind of energy was summarized. The indicators for evaluation of solar energy resources, including richness, stability, utilization value and mean of effective sunshine duration, are incorporated into three main parameters. And the score of principal component is considered as the main factor of the resource evaluation. The evaluation and prediction of solar energy in a region are efficient and accurate by this method, which provide guidance for utilization and development of solar energy.

study area is located at the southwest border of Yunnan Province and the southward extended part of Nushan Mountain, with complex and fragile geo-environmental conditions. Deep geological survey and mathematical analytical investigation on the geohazard distribution and hazard-causing mechanisms in this area were carried out in this study. The results revealed that: (1) The development of geohazards was affected differently by different slope shapes, slope structures and elevations; (2) Most of the geohazards were developed in medium shallow cut ridge-like medium-height mountainous geomorphological region and shallow cut steamed bun-like low and medium-height mountainous geomorphological region, and they were relatively concentrated on tectonic zones like fault zones; (3) The slopes formed by loose earth piling up on the surface of Indo-Chinese magmatic rock and Lancang Group metamorphic rock formations were most prone to slope instability and even landslide. The deep study on the geohazard distribution and hazard-causing mechanisms can provide geoscientific basis and reference for the prevention and mitigation work of geohazards under similar geo-environmental conditions.