Варизонные гетероструктуры Al-=SUB=-x-=/SUB=-In-=SUB=-y-=/SUB=-Ga-=SUB=-1-x-y-=/SUB=-P-=SUB=-z-=/SUB=-As-=SUB=-1-z-=/SUB=-/GaAs для фотоэлектрических преобразователей

The AlxInyGa1-x-yPzAs1-z/GaAs graded-gap heterostructures were grown by the temperature gradient zone recrystallization with a liquid zone reciprocating, where energy band gap varied from 1.43 to 2.2 eV. The influence of technological parameters on the varying in the energy band gap of the grown AlxInyGa1-x-yPzAs1-z/GaAs solid solutions is investigated. In the p-AlxInyGa1-x-yPzAs1-z/n-GaAs heterostructure, the maximum energy band gap gradient of 10490 eV/cm is reached, and an increase in the external quantum efficiency is shown in the wavelength range of 500-900 nm.

Division of paraffin melting zone based on multiscale experiments

Phase change energy storage materials are widely used in the field of renewable energy. Paraffin is one of the common phase change energy storage materials. As a multi-component hydrocarbon mixture, the melting of paraffin is different from that of pure substance. In addition to the solid and liquid zones, there is also a fuzzy zone in which solid and liquid coexist. In this paper, the melting characteristics of paraffin in phase transition zone are studied by multi-scale experiments. Through the visualization experiment of square cavity paraffin melting, the solid zone, fuzzy zone and liquid zone are determined, and the moving process of phase interface is tracked by digital pictures and infrared heat maps. The evolution process of the pore structure in the fuzzy zone under different temperatures is photographed by means of the micro experiment, and it is revealed that there are two areas in the fuzzy zone, porous media area and multiphase flow area. The results show that the melting process of paraffin can be divided into four zones: liquid zone, multiphase flow zone, porous media zone and solid phase zone. According to the polarizing optical microscopy (POM) picture, the continuous phase and discrete phase transition relationship between solid wax crystal and liquid paraffin is captured. The POM picture is statistically analyzed, and the critical liquid phase ratio of the transition from porous media area to multiphase flow area is given under experimental conditions.

Metallurgical characteristics of refining slag used for high manganese steel

High manganese steel has excellent mechanical properties, which has garnered much attention. Whereas the research on the refining slag used for high Mn steel is very limited. In this study, the metallurgical characteristics of refining slag for high Mn steel were investigated based on thermodynamic calculation with FactSage 6.3 and slag-metal equilibrium reaction in MgO crucible. The calculated liquid zones of T ≤ 1873 K of CaO-SiO2-Al2O3-8%MgO-5%MnO system are located in the middle region of pseudo-ternary CaO-SiO2-Al2O3. For CaO-SiO2-Al2O3-8%MgO-MnO system, the apparent liquid zone at 1873 K enlarges with MnO content in slag increasing, and moves toward the direction of SiO2 and Al2O3 content increasing. For CaO-SiO2-Al2O3-MgO-MnO system, the liquidus zone shrinks with the basicity increasing, and moves toward the direction of Al2O3 content increasing. The measured MnO content in top slag reacted with high Mn steel was much higher than that reacted with conventional steels. In present experiments, the MnO content was around 5% when CaO-SiO2-Al2O3-MgO slag with basicity of 4 was in equilibrium with high Mn steel (Mn = 10, 20%) at 1873 K. The inclusions in master high Mn steel were mainly MnO type. After reaction with top slag, most inclusions transformed to MnO-SiO2 system and MnO-Al2O3-MgO system, in which the MnO content still shared the majority. Thermodynamic calculations show that SiO2 in top slag can be reduced by [Mn] in steel to supply [Si] under present experimental condition, which subsequently reacts with [O] in steel bath to form SiO2.

Solidification of Aluminum Alloy Weld Metal

The characteristics of the structure of solidified weld metal vary with its solidification process, which affects the occurrence of defects such as blowholes and solidification cracking. With respect to the solidification process during casting, a great deal of research has been carried out to control the process so that the solidification structure and its characteristics can be adjusted preferentially. This article describes the analytical results for the same two concerning the cooling behavior of the solid-liquid zone during the solidification process, the change in fraction of solid and local solidification rate.

Влияние висмута на структурное совершенство и люминесцентные свойства тонкопленочных упругонапряженных гетероструктур Al-=SUB=-x-=/SUB=-In-=SUB=-y-=/SUB=-Ga-=SUB=-1-x-y-=/SUB=-Bi-=SUB=-z-=/SUB=-Sb-=SUB=-1-z-=/SUB=-/GaSb

The effect of bismuth on the structural perfection and the luminescent properties of Al_ x In_ y Ga_1– x – y Bi_ z Sb_1– z /GaSb heterostructures has been studied. The optimal parameters of the process of zone recrystallization with temperature gradient at which epitaxial AlInGaBiSb layers have the minimum roughness and high structural perfection have been revealed: temperature gradient 1 ≤ G ≤ 30 K/cm, the liquid zone thickness 60 ≤ l ≤ 100 μm, the temperature range 773 K ≤ T ≤ 873 K, and bismuth concentration 0.3–0.4 mol fraction.

Oxide Self-Flux in Optical Floating Zone Crystal Growth of Nickel Niobate (NiNb2O6)

Growing crystals of nickel niobate (NiNb2O6), we noticed that changing growth conditions allowed our material to enter different areas of the phase diagram. In particular, we found that excess material accumulated within and above the liquid zone. Analysis showed that this was an unincorporated constituent. Changing the ratio of the constituent oxides - an excess of ~4% of either NiO or Nb2O5 gave us the opportunity to investigate changes in zone stability, melting temperature and quality of the resulting crystal. We found that a small excess of nickel oxide decreases the melting temperature significantly, and created the best pseudo-rutile NiNb2O6 crystal studied, while higher amounts of niobium oxide allowed us to stabilize the NiNb2O6 columbite phase. This research reinforces the idea that self-flux as a travelling solvent can significantly impact crystal growth parameters and quality.