Optical properties and electrical properties of heavily Al-doped ZnSe layers

Oh, D.C.,Takai, T.,Im, I.H.,Park, S.H.,Hanada, T.,Yao, T.,Song, J.S.,Chang, J.H.,Makino, H.,Han, C.S. SLACK INCORPORATED 2008 Journal of vacuum science & technology. an officia Vol.26 No.2

Roles of Kinetics and Energetics in the Growth of AlN by Plasma-Assisted Molecular Beam Epitaxy

I. H. Im,D. C. Oh,J. H. Chang,M. W. Cho,S. W. Lee,T. Yao,T. Minegishi,T. Hanada 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.3

The roles of kinetics and energetics in the growth processes of AlN on c-sapphire by plasmaassisted molecular beam epitaxy are investigated by varying the growth rate from 1 to 31 °A/min and the substrate temperature from 800 to 1000 C. The energetics is found to govern the growth of AlN in the low-growth rate region even at a low substrate temperature of 800 C owing to the enhanced residence time of adatoms, thereby increasing the surface migration length. As the growth rate increases, the growth tends to be governed by kinetics because of a reduction in the residence time of adatoms. Consequently, the surface roughness and crystal quality are greatly improved for the low-growth-rate case. In addition, the lattice strain relaxation is completed from the beginning of epitaxy for energetics-limiting growth while lattice strain relaxation is retarded for kinetics-limiting growth because of pre-existing partial strain relaxation. Energetics becomes more favorable as the substrate temperature is raised because of an increase in the surface diusion length owing to an enhanced diusion coecient. Consequently high-crystal-quality AlN layers are grown under the energetics-limiting growth condition with a screw dislocation density of 7.4 × 108 cm−2 even for a thin 42-nm thick film.

Structural Properties of CrN Buffers for GaN Growth

W. H. Lee,오동철,한창석,이현용,I. H. Im,J. J. Kim,K. Sumitani,구경완,M. W. Cho,O. Sakata,조성준,홍순구,S. T. Kim,T. Minegishi,T. Yao,T.Hanada 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.3

We have investigated the structural properties of CrN layers grown on (0001) Al2O3 substrates by molecular-beam epitaxy. The CrN layers of high-crystal quality are obtained at a low growth temperature of 500 C. X-ray diraction studies indicate that the CrN layers grow along the <111> direction with a cubic structure. In-situ reflection high-energy electron diraction investigations clarify that the CrN layers have the following epitaxy relationship with the Al2O3 substrates: <12- 1> of (111) cubic CrN // <11-20> of (0001) corundum Al2O3 and <101> of (111) cubic CrN // <1-100> of (0001) corundum Al2O3. Based on the above results, the mismatch of the in-plane lattice spacing between the CrN layers and the Al2O3 substrates is evaluated to be around 6.6 %. When the CrN layers are used as the buer layers for GaN growth, the GaN layers grown on the CrN layers show well-resolved excitonic emission lines in the photoluminescence spectra, whereas the GaN layers grown without the CrN layers exhibit a broad near-band-edge emission. It is suggested that CrN buers are eective in relieving the lattice mismatch between Al2O3 substrates and GaN layers.

A Study on SiC Particulates Reinforced Al-Li Composites Consolidated by Hot Isostatie Pressing

Hanada, K .,Murakoshi, Y .,Negishi, H .,Sano, T. 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.3

SiC particulates reinforced Al-Li (Al-Li/SiCp) composite powders were produced by mechanical milling and were consolidated by hot isostatic pressing (HIP) at various temperatures and pressures. Prior to HIP, the composite powders compacted upto a relative density of 80% were put into a steel capsule and were degassed while heating. Thermogravity analysis revealed that the moisture adsorbed on the surface of composite powders could be removed at 508 K. Based on the result, degassing was carried out at 573 K and 773 K for 1 hour. SiC particulates of HIPped specimens were aggregated on the prior particle boundaries of Al-Li matrix powders under all HIP conditions. The density and tensile strength of HIPped specimens increased and the ductility decreased with increasing HIP temperature and pressure.

Non-Inductive Plasma Current Start-up Experiment by Electron Cyclotron Heating in the CPD Device

T. Yoshinaga,K. Hanada,K. Sato,K. Nakamura,H. Zushi,H. Idei,M. Sakamoto,M. Hasegawa 한국진공학회 2007 한국진공학회 학술발표회초록집 Vol.16 No.2

Effect of swaging on Young@?s modulus of β Ti-33.6Nb-4Sn alloy

Hanada, S.,Masahashi, N.,Jung, T.K.,Miyake, M.,Sato, Y.S.,Kokawa, H. Elsevier 2014 Journal of the mechanical behavior of biomedical m Vol.32 No.-

The effect of swaging on the Young's modulus of β Ti-33.6Nb-4Sn rods was investigated by X-ray diffraction, thermography, microstructural observations, deformation simulator analysis and cyclic tensile deformation. Stress-induced α'' martensite was stabilized by swaging, dependent on the diameter reduction rate during swaging. Thermography and deformation simulator analysis revealed that swaged rods were adiabatically heated, and consequently, stress-induced α'' underwent reverse transformation. Young's modulus, which was measured by the slope of the initial portion of the stress-strain curve, decreased from 56GPa in the hot-forged/quenched rod to 44GPa in the rapidly swaged rod with a high reduction rate and to 45GPa in the gradually swaged rod with a low reduction rate. The tangent modulus, which was measured by the slope of the tangent to any point on the stress-strain curve, decreased with strain even in the linear range of the stress-strain curve of the hot-forged/quenched rod and the rapidly swaged rod, while the tangent modulus remained unchanged for the gradually swaged rod. It was found that Young's moduli in swaged β Ti-33.6Nb-4Sn rods were affected by stabilized α'' martensite. Low Young's modulus of 45GPa and high strength over 800MPa were obtained when the reverse transformation by adiabatic heating was suppressed and the stress-induced α'' was sufficiently stabilized by gradual swaging to a 75% reduction in cross section area.

Mechanical properties and microstructures of β Ti-25Nb-11Sn ternary alloy for biomedical applications

Jung, T.K.,Semboshi, S.,Masahashi, N.,Hanada, S. Elsevier 2013 Materials science & engineering. C, Materials for Vol.33 No.3

The mechanical properties and microstructures of β Ti-25%Nb-11%Sn ternary alloy rods were investigated for biomedical applications as a function of heat treatment temperature after swaging by an 86% reduction in cross-section area. An as-swaged rod consisting of a β (bcc) single phase shows a low Young's modulus of 53GPa, which is interpreted in terms of both the metastable composition of the β alloy undergoing neither an athermal ω transformation nor a deformation-induced ω transformation and <110>texture development during swaging. Heat treatment at 673K (400<SUP>o</SUP>C) for 2h leads to a high strength of approximately 1330MPa and a high spring-back ratio of yield stress to Young's modulus over 15x10<SUP>-3</SUP>, with acceptable elongation. This high strength is attributable to needle-like α precipitates, which are identified by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and high-resolution electron microscopy (HREM).

IN VITRO DEVELOPMENT OF BOVINE ONE-CELL EMBRYOS FERTILIZED IN VITRO IN SERUM- AND FEEDER CELL-FREE CULTURE SYSTEMS

Ohboshi, S.,Hanada, K.,Zhao, J.,Hattori, M.,Fujihara, N.,Umetsu, R.,Yoshida, T.,Tomogane, H. Asian Australasian Association of Animal Productio 1996 Animal Bioscience Vol.9 No.5

The purpose of this study was to evaluate some factors in the bovine embryonic development from one-cell to blastocyst using modified synthetic oviduct fluid medium (mSOFM), after maturation and in vitro fertilization of the oocytes. The embryonic development to the blastocyst stage was assessed at 7-10 days after in vitro fertilization, and the total cells in the blastocysts were counted by staining nuclei with fluorochrome. Some commercial calf sera (CS) and a superovulated cow serum had different effects on the embryonic development to the blastocyst stage (8.6-21.4%), dependent upon their product lots, although the development might not be affected at least by serum progesterone levels. ${\beta}$-Mercaptoethanol (${\beta}$-ME) supplemented into mSOFM was effective to the embryonic development (27.8%), as well as the co-culture system with cumulus cells (19.5%). In a serum- and feeder cell-free culture using mSOFM containing several growth factors and ${\beta}$-ME instead of CS plus co-cultured cumulus cells, bovine serum albumin (BSA, fraction V), but not polyvinyl alcohol (PVA), was highly effective in embryonic development to the blastocyst stage, almost comparable to CS in the serum-contained culture (CS, BSA and PVA; 27.8, 19.5 and 5.7%, respectively). However, fatty acid free BSA rather reduced the number of developed blastocysts, compared with fraction V BSA (7.3 vs 29.4%). In the serum- and feeder cell-free culture, supplement of glucose to the medium (final 2.0 mM) stimulated the cell proliferation of developing embryos 120 hr after in vitro fertilization. These results indicated that a serum-free medium supplemented with ${\beta}$-ME could successfully support the development of bovine one-cell embryos to the blastocyst stage. Moreover, supplement of glucose and fatty acids to the medium might support preferably the development and cell proliferation of embryos.

Changes of Serum Calcium Concentration, Frequency of Ruminal Contraction and Feed Intake Soon after Parturition of Dairy Cows Fed Difructose Anhydride III

S. Wynn,M. Teramura,T. Sato,M. Hanada 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.1

Requirements to control the large decrease in serum calcium (Ca) due to parturition and to increase the feed intake soon after parturition have been well accepted in dairy cows. This study was aimed to investigate the feed intake affected by serum Ca concentration with difructose anhydride (DFA) III supplement in dairy cows soon after parturition. Fourteen transition Holstein cows were divided into DFA and control (CONT) groups within 1 to 5 parity variations in each group. Measurement schedule for an individual cow was from 14 d before parturition to 7 d following parturition. The cows in DFA group were supplied 0.2 kg/head/d of DFA III feed containing 40 g of pure DFA III while the cows in CONT group received no DFA III. Other feeding procedures were the same for all cows in both groups. At parturition (d 0), serum Ca concentration sharply declined in both groups (p<0.05). Time interval for recovery from decreased serum Ca to its normal range (>9.0 mg/dL) tended to be faster in DFA group (12 h) than in the CONT group (48 h), but the differences were not significant. Active ruminal contraction was observed in DFA group at following parturition of d 1 (p<0.05), d 3 (p<0.05), and d 5 (p<0.01). Dry matter (DM) intake did not differ between the groups. However, positive correlations were observed between serum Ca concentration and ruminal contraction (p<0.001), and between ruminal contraction and DM intake (p<0.001) during following parturition. According to multiple regression analysis (R2 = 0.824, p<0.001), the DM intake was positively affected by serum Ca concentration and ruminal contraction. These results suggest that feed intake soon after parturition in dairy cows can be increased by improvement of serum Ca concentration and active ruminal contraction, but DFA III supplementation in this study did not improve the lower serum Ca concentration due to parturition.

Changes of Serum Calcium Concentration, Frequency of Ruminal Contraction and Feed Intake Soon after Parturition of Dairy Cows Fed Difructose Anhydride III

Wynn, S.,Teramura, M.,Sato, T.,Hanada, M. Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.1

Requirements to control the large decrease in serum calcium (Ca) due to parturition and to increase the feed intake soon after parturition have been well accepted in dairy cows. This study was aimed to investigate the feed intake affected by serum Ca concentration with difructose anhydride (DFA) III supplement in dairy cows soon after parturition. Fourteen transition Holstein cows were divided into DFA and control (CONT) groups within 1 to 5 parity variations in each group. Measurement schedule for an individual cow was from 14 d before parturition to 7 d following parturition. The cows in DFA group were supplied 0.2 kg/head/d of DFA III feed containing 40 g of pure DFA III while the cows in CONT group received no DFA III. Other feeding procedures were the same for all cows in both groups. At parturition (d 0), serum Ca concentration sharply declined in both groups (p<0.05). Time interval for recovery from decreased serum Ca to its normal range (>9.0 mg/dL) tended to be faster in DFA group (12 h) than in the CONT group (48 h), but the differences were not significant. Active ruminal contraction was observed in DFA group at following parturition of d 1 (p<0.05), d 3 (p<0.05), and d 5 (p<0.01). Dry matter (DM) intake did not differ between the groups. However, positive correlations were observed between serum Ca concentration and ruminal contraction (p<0.001), and between ruminal contraction and DM intake (p<0.001) during following parturition. According to multiple regression analysis ($R^2$ = 0.824, p<0.001), the DM intake was positively affected by serum Ca concentration and ruminal contraction. These results suggest that feed intake soon after parturition in dairy cows can be increased by improvement of serum Ca concentration and active ruminal contraction, but DFA III supplementation in this study did not improve the lower serum Ca concentration due to parturition.