The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composi...The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composition, structure and surface morphology of the products were investigated through FT-IR, XRD and SEM. The results show that the products ceramize and crystallize gradually with the increase of the temperature. When the molar ratio and reaction temperature are 3:2 and 850 ℃, respectively, the products have high purity, compact structure and nice shape. The oxidation treatment at 450 ℃ will not impair the composition and structure of boron nitride but effectively remove the impurities.展开更多
The way of increase of storage period of agricultural raw materials under the influence of low frequency electromagnetic field (EMF LF) has been considered in the article. Existing developments of the EMF LF usage on ...The way of increase of storage period of agricultural raw materials under the influence of low frequency electromagnetic field (EMF LF) has been considered in the article. Existing developments of the EMF LF usage on the base of patents have been examined. The results of EMF LF processing of wood, wine, seeds, vegetative, fish and meat products have been presented.展开更多
基金Funded by the National Natural Science Foundation of China (Nos.50902150 & 90916019)the Graduate Innovation Foundation of the National University of Defense Technology(No.S100103)
文摘The amorphous boron nitride ceramic powders were prepared at 750-950 ℃ by the low-cost urea route, and the effects of preparation temperatures, molar ratios of the raw materials and oxidation treatment on the composition, structure and surface morphology of the products were investigated through FT-IR, XRD and SEM. The results show that the products ceramize and crystallize gradually with the increase of the temperature. When the molar ratio and reaction temperature are 3:2 and 850 ℃, respectively, the products have high purity, compact structure and nice shape. The oxidation treatment at 450 ℃ will not impair the composition and structure of boron nitride but effectively remove the impurities.
文摘The way of increase of storage period of agricultural raw materials under the influence of low frequency electromagnetic field (EMF LF) has been considered in the article. Existing developments of the EMF LF usage on the base of patents have been examined. The results of EMF LF processing of wood, wine, seeds, vegetative, fish and meat products have been presented.