In this paper, Mg-doped AlN epilayers for power semiconductor devices are grown by mixed-source hydridevapor phase epitaxy. Magnesium is used as p-type dopant material in the grown AlN epilayer. The AlN epilayers on theGaN-templated sapphire substrate and GaN-templated-patterned sapphire substrate (PSS), respectively, as the base substratesfor device application, were selectively grown. The surface and the crystal structures of the AlN epilayers were investigatedby field emission scanning electron microscopy (FE-SEM) and high-resolution-X-ray diffraction (HR-XRD). From the X-rayphotoelectron spectroscopy (XPS) and Raman spectra results, the p-type AlN epilayers grown by using the mixed-sourceHVPE method could be applied to power devices.
The demand for lithium has increased sharply due to the explosive increase in lithium secondary batteries forenvironment-friendly vehicles (EV: Electric Vehicle, HEV: Hybrid Electric Vehicle, PHEV: Plug-in Hybrid Electric Vehicle).
Traditionally, lithium has been produced mainly from lithium-containing minerals and brine, and recently it also has beenrecovered along with other valuable metals by recycling cathode materials of lithium secondary batteries. In this study, wecomprehensively reviewed various recovering precesses of lithium from lithium-containing substances.
A computational analysis has been carried out to get a thorough and full understanding on the effects ofconvective process parameters on double-diffusive convection during the growth of mercurous bromide (Hg2Br2) crystals onearth and under μg conditions. The dimensional maximum magnitude of velocity vector, |U|max decreases much drasticllynear Ar = 1, and, then since Ar = 2, decreases. The μg conditions less than 10−2g make the effect of double-diffusionconvection much reduced so that adequate advective-diffusion mass transfer could be obtained.
Electric arc furnace dust (EAFD), which is a dust waste generated in the steel manufacturing process, containsheavy metals. Recently, researches of recycling a large amount of valuable metals such as zinc and iron in EAFD arebeing actively carried out. In this study, EAFD is used as a substitute for cobalt in blue ceramic pigments without anypretreatment. Then, the synthesized blue ceramic pigment using EAFD was micronized and formulated as a ceramic ink forinkjet printer. The particle size distribution, crystal structure and color characteristics during the micronization process wereinvestigated for the development of ceramic ink. Co0.75Zn(EAFD)0.25Al2O4 ceramic pigments showed excellent blue coloricproperties and monomodal distribution through micronization process. The average particle size of Co0.75Zn(EAFD)0.25Al2O4ceramic pigments after 3 hours of milling was 0.271 μm, which is smaller than 0.303 μm, which is the average particle sizeof CoAl2O4 ceramic pigments without EAFD after 5 hours of milling. Especially, it was confirmed that Co0.75Zn(EAFD)0.25Al2O4ceramic pigments showed a color difference (ΔE*ab) value of 5.67, which smaller than ΔE*ab value of CoAl2O4 duringmicronization. These results show that EAFD can be used as a raw material for a blue ceramic pigment by replacingexpensive cobalt without any pretreatment.
In this study, the development of transparent UV blocking material using TiO2−x oxide thin film process wasdeveloped. A process technology is related to a process technology for making a sample with ultraviolet-shielding propertyof visible light transmittance of 78 % or more (total light transmittance at 550 nm) and of a UV cut-off characteristic ofmore than 95 % at 315 nm in ultraviolet wavelength band. In this study, it is possible to establish a flexible device processcondition of high performance ultraviolet (UV) shielding thin film, to design mixed type of transparent flexible device withheterogeneous characteristics and to formulate composite deposition technology, according to various market demands.
Establishment of actual roll-to-roll continuous process and equipment and process technology will affect related industriesgreatly.
EPS (expanded polystyrene) is one of the most used building materials for insulation that is favored by itsexcellent heat insulation, economical efficiency and lightweight characteristics. However, EPS is vulnerable to the fire andproducing large amount of toxic gases in case of fire. Therefore, ultra-lightweight geopolymer which can replace EPS isfabricated by using IGCC (integrated gasification combined cycle) fused slag and Si sludge as raw materials and thepossibility of replacement on ultra-lightweight geopolymer for EPS as an insulation building material was evaluated in thisstudy. Ultra-lightweight geopolymer can be fabricated with the pulverized IGCC fused slag having low carbon content anddensity, compressive strength, thermal conductivity were 0.064 gcm3, 0.04 MPa, and 0.072W/mK, respectively. The thermalconductivity of ultra-lightweight geopolymer is 1.5~2.0 times higher than that of EPS suggested in the KS M 3808; however,the thermal conductivity value of geopolymer is meaningful and competitive to that of EPS in the market. Therefore, ultralightweightgeopolymer can be applicable to the building material for thermal insulation purpose and have an enoughpossibility to replace EPS in the future because it is not only much safer than EPS in case of fire but also it can befabricate by using waste materials from the industry.
AlN (Aluminum Nitride) crystal which could be used to substrates for UV LEDs was grown by PVT ((PhysicalVapor Transport) method. 3 inch AlN single crystal with a thickenss of 4 mm was grown using Polycrystalline seed for120 hours. In this report, a result of 3 inch polycrystalline bulk AlN growth behavior using large size crucible and growthcondition were reported.