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Undoped and Nb-doped SrTiO3/TiO2 (STO/TO) eutectic solids were fabricated from the melt at a eutectic point of STO and TO by unidirectional solidification. Fabricated undoped and Nb:STO/TO eutectic solids were composed of the TiO2 rod-like and the SrTiO3 matrix phases, and the periodic and uniform eutectic morphology could be achieved in the Nb:STO/TO eutectic solids by stable control of the liquid-solid interface during the fabrication. The thermal conductivity of the Nb:STO/TO eutectic solid was less than half of that of the Nb:STO single crystal owing to the decrease of the lattice thermal conductivity by phonon scattering at the grain boundaries. The figures of merit ZT's of the Nb:STO/TO eutectic solid, parallel and perpendicular to the growth direction, were ∼ 0.007 and ∼ 0.0004, respectively. The small ZT's are attributable to the higher electrical resistivity originating from the insufficient carrier doping and high electrical resistivity of the TO phase. [ABSTRACT FROM AUTHOR]

In this study, Eu and Ce doped LiSrI single crystals were explored and the scintillation performance was reported at the first time. Eu and Ce doped LiSrI single crystals were grown by the Bridgman-Stockbarger method in a quartz ampoule with 3 mm inner diameter. Growth rate was 0.06 mm/min. Circular samples with 1 mm thickness were obtained from the grown crystal. The grown Eu doped LiSrI crystal demonstrated Eu 4f-5d emission peak at 420 nm under alpha-ray excitation. In the case of Ce doped one, double emission peaks at 360 and 400 nm were observed. The light yield of the Eu doped LiSrI was around 35,000 photon/MeV for 662 keV gamma-ray and 24,000 photon/5.5 MeV for alpha-ray. Energy resolution of the Eu doped LiSrI was 5.2%@662 keV. Scintillation decay time of the grown Ce and Eu doped LiSrI under 662 keV gamma-ray was 23.8 ns (50%) 212 ns (50%) and 545 ns 100%, respectively. [ABSTRACT FROM AUTHOR]

Ce-doped garnet-type single crystals with improved dopant distribution were grown by the micro-pulling-down method using a modified Iridium crucible and effects of dopant distribution improvement on the optical and scintillation properties were investigated. Ce-doped YAlO (Ce:YAG) and Gd(Ga,Al)O (Ce:GGAG) single crystals with improved dopant distribution could be grown by a Iridium crucible with five capillaries (5C). The Ce:YAG and Ce:GGAG single crystals (5C) showed higher transmittance than the single crystals grown by an original Iridium crucible with one capillary (1C). In addition, a clear photo-peak could be observed in the pulse-height spectrum of the Ce:YAG single crystal (5C) under γ-ray irradiation while there was no peak in the spectrum of the Ce:YAG single crystal (1C). [ABSTRACT FROM AUTHOR]

Li-containing materials can be applied as neutron scintillators, and LiBaF can discriminate neutron and gamma rays. Moreover, LIF/LiBaF can have higher cross section of thermal-neutron capture compared with LiBaF. In this study, LiF (82.5 mol%) and (Ba RE)F (17.5 mol%, RE = Ce and Eu, x = 0.002) eutectic crystals, LiF/RE:LiBaF, were grown by the micropulling down method with different pulling rates (growth rate) in order to observe the eutectic structure. Lamellar microstructure was formed for each pulling rate. LiF/Ce:LiBaF excited by 5.5-MeV alpha rays had a broad peak at ~350 nm corresponding to 5 d-4 f transition of Ce. On the other hand, LiF/Eu:LiBaF had two scintillation processes; a sharp emission was originated from P → S transitions in the 4 f electronic configuration of Eu at 360 nm, and a broad one was attributed to Eu trapped exciton recombination at 400-450 nm. Since scintillation light was observed for these materials, these scintillators are sensitive to neutrons. [ABSTRACT FROM AUTHOR]

A hybrid two-phase model, incorporating lattice Boltzmann method (LBM) and finite difference method (FDM), was developed to investigate the coalescence of two drops during their thermocapillary migration. The lattice Boltzmann method with a multi-relaxation-time (MRT) collision model was applied to solve the flow field for incompressible binary fluids, and the method was implemented in an axisymmetric form. The deformation of the drop interface was captured with the phase-field theory, and the continuum surface force model (CSF) was adopted to introduce the surface tension, which depends on the temperature. Both phase-field equation and the energy equation were solved with the finite difference method. The effects of Marangoni number and Capillary numbers on the drop's motion and coalescence were investigated. [ABSTRACT FROM AUTHOR]