Wenbo Bi

Granite slabs are a significant building material, which is widely used in the construction field. An important process in granite slab processing is drying treatment. Currently traditional drying methods such as natural drying and hot air drying have inherent drawbacks such as high energy consumption and low efficiency, which pose higher requirements for drying processes. Herein, a kinetic model of microwave drying for characterizing the variation rule of moisture content in the drying process of granite sheets is established. The effects of microwave power and plate thickness on the drying characteristics of granite slabs are studied through a large number of comparative experiments. On this basis, the variation rule of granite slab moisture ratio during the drying process is further obtained. Experimental results show that microwave drying of granite mainly includes accelerated drying and reduced drying stages, which are consistent with the predicted results of the model. These excellent results prove the effectiveness of the proposed model in this article.

Lower warp is required for the single crystal silicon wafers sawn by a fixed diamond wire saw with the thinness of a silicon wafer. The residual stress in the surface layer of the silicon wafer is the primary reason for warp, which is generated by the phase transitions, elastic-plastic deformation, and non-uniform distribution of thermal energy during wire sawing. In this paper, an experiment of multi-wire sawing single crystal silicon is carried out, and the Raman spectra technique is used to detect the phase transitions and residual stress in the surface layer of the silicon wafers. Three different wire speeds are used to study the effect of wire speed on phase transition and residual stress of the silicon wafers. The experimental results indicate that amorphous silicon is generated during resin bonded diamond wire sawing, of which the Raman peaks are at 178.9 cm⁻¹ and 468.5 cm⁻¹. The ratio of the amorphous silicon surface area and the surface area of a single crystal silicon, and the depth of amorphous silicon layer increases with the increasing of wire speed. This indicates that more amorphous silicon is generated. There is both compressive stress and tensile stress on the surface layer of the silicon wafer. The residual tensile stress is between 0 and 200 MPa, and the compressive stress is between 0 and 300 MPa for the experimental results of this paper. Moreover, the residual stress increases with the increase of wire speed, indicating more amorphous silicon generated as well.