The improvement of industrial parameters like the basicity and sintering temperature and the selection of raw materials to form the acicular calcium ferrites become the hot topic in sintering production. However, the experimental with the sintering pot in the laboratory is still a main method up to now, no effective mathematical model or experience equations were developed. Factsage is a software for thermodynamic calculation in ironmaking and steelmaking. In present study, Factsage was used to calculate the liquid phases formulation during the sintering. The effect of the chemical compositions on the liquidus projection was also discussed. It was found that the content of liquid phase formed is about 25%-70% at 1 250°C due to their chemical composition. The more SiO2, the easier to form liquid phase. The experiments were carried out for the validation. It was found that the calculations of the mass of liquid phase generation cannot give a very good and accurate agreement with the measurement of the melting behavior of the sample quantificationally, however, for the ability of the liquid phase formation during the sintering, the calculations can give a good qualitative results, especially in the temperature of melting begin and the temperature of 50% shrinkage. The calculations reported in this study can be used to estimate the sintering behavior of the iron ores under a certain industrial condition to reduce the extra experiments. The experiments also shows that the calculations by Factsage can give some good explanations on the phenomenon of the melting behavior of different samples.

In this letter, a method of using selective area growth (SAG) technique was proposed to fabricate the enhancement-mode (E-mode) AlGaN/GaN heterostructure field effect transistors (HFETs), which can effectively avoid the plasma treatment damage to the active region of HFETs in comparison with the conventional methods. The SAG-HFETs exhibited a good performance of the maximum drain current of 300 mA/mm and peak transconductance of 135 mS/mm with a larger positive threshold voltage of 0.4 V. The results indicate that the SAG technique is a promising method to realize the high performance E-mode GaN based HFETs.

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Abstract:The effect of cooling rate on the crystallization of perovskite in high Ti-bearing blast furnace (BF) slag was studied using confocal scanning laser microscopy (CSLM). Results showed that perovskite was the primary phase formed during the cooling of slag. On the slag surface, the growth of perovskite proceeded via the successive production of quasi-particles along straight lines, which further extended in certain directions. The morphology and structure of perovskite was found to vary as a function of cooling rate. At cooling rates of 10 and 30 K/min, the dendritic arms of perovskite crossed obliquely, while they were orthogonal at a cooling rate of 20 K/min and hexagonal at cooling rates of 40 and 50 K/min. These three crystal morphologies thus obtained at different cooling rates respectively corresponded to the orthorhombic, cubic and hexagonal crystal structures of perovskite. The observed change in the structure of perovskite could probably be attributed to the deficiency of O 2 , when Ti 2 O 3 was involved in the formation of perovskite.