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Extensive reflection nebulae have been discovered around GGD27 IRS and around W75N IRS by mapping the infrared polarization in the K band.
It was found that the infrared radiation from both objects is extended at λ = 2.2 μm, by using the Agematsu 1-m, the UH 2.2-m, and the UKIR 3.8-m telescopes. We have carried out polarization mapping with the Kyoto polarimeter on the UKIRT in August 1985.
Metal Organic Decomposition (MOD)-made BaTiO3 (BT) thin films were prepared for Resistive Random Access Memory (ReRAM) under various annealing conditions and investigated for improving the properties of bipolar-type resistive switching, focusing on the relation between oxygen vacancies and the behavior of resistive hysteresis. BT thin films with both pre- and final- annealing in nitrogen showed the resistive hysteresis of bipolar-type switching with current ON/OFF ratios of 2 orders of magnitude for both bias polarities. Finally they showed the endurance property with the 106 switching cycles. It was suggested that oxygen vacancies near the oxide surface (both interfaces at metal electrode/oxide and between layer-by-layered oxide layers) are increased by N2 annealing and enhanced the interface-type resistive switching. Pre-annealing in N2 was also found to be very effective to improve endurance properties, implying that not only the electrode/oxide interface but also the middle part of the film would contribute the interface-type mechanism.
We have simulated the 3D growth of a Rayleigh-Taylor instability in the expanding envelope of SN 1987A using the Adaptive Mesh Refinement Scheme utilizing a resolution of 4096−3. When the sinusoidal velocity perturbation amplitude is 10%, heavy element tongues of the He/H interface penetrate into the envelope with a high velocity.
An extensive survey of [C II] line emission at 158 microns using the balloon borne telescope (BICE) has provided a complete map of the emission intensity distribution in the first and the fourth quadrants of the galactic plane (280° < l < 80°, −5° < b < 5°: Okuda et al. 1993). The emission is very extended throughout the galactic plane in which three intensity maxima are seen towards the tangential directions of the Scutum and the Norma arms as well as in the Galactic center region. However the Galactic center maximum is much less prominent compared with the two other distributions, unlike the case of far infrared continuum and CO emissions.
The X-ray background in the energy range above 2 keV is highly uniform except for an excess component along the Galactic plane. The excess along the plane is considered to be associated with our Galaxy, whereas the rest of the emission is believed to be of extragalactic origin. In this paper, the X-ray background at high Galactic latitude is discussed and is designated as the CXB (cosmic X-ray background) to distinguish it from the Galactic origin.
Cosmic X-rays were observed with three sets of proportional counters covering the energy range between 0.15 and 20 keV. The detector born on a spinning rocket scanned a celestial region in which the galactic latitude bII changed from 30° to −55° across the galactic plane in the Cygnus-Cassiopeia region. The spectrum of Cyg XR-2 thus obtained is represented by a thermal bremsstrahlung of temperature 3.4 keV modified by the interstellar absorption for the hydrogen column density of 3 × 1021 cm−2. The diffuse component showed an interstellar absorption effect, which was however found much weaker than one would expect if the diffuse component were due entirely to be of extragalactic origin. The spectrum obtained in the highest latitude region is represented approximately by a power law E−1.8 but shows a possible trough at about 1 keV.
We developed a new GaN on SiC growth method by metalorganic vapour phase epitaxy (MOVPE) using of a single 2-dimension-growth step. Prior to epitaxy, to inhibit pre-reaction of Si-face SiC substrate with TMGa and NH3, TMAl was flowed without NH3. 1.5 μm of undoped crack-free GaN was grown on 6H-SiC (Si-face). Without buffer layer, the vertical resistance of GaN/SiC structure was found to be around 82.1Ω as determined by I-V characteristic. Further reduction in vertical resistance is expected by growth of n-GaN (1.5μm)/SiC structure (300μm). We also expect a SiC-based GaN heterostructure vertical FET will achieve high power and high switching speed performance.
A new nano-fabrication process, utilizing protein supramolecules, biomineralization, and nano-etching was proposed, which was named Bio Nano Process (BNP). The main processes of the BNP include the nanoparticle (NP) or nanowire (NW) synthesis utilizing bio-template (biomineralization) and nanostructure fabrication utilizing self-organization of protein supramolecules. Proteins are so designed to produce the final structures. The space where nano functional structures are fabricated is named an “Active Bio-field”. It was proven that the process has vast potential to be applied to a wide range of quantum effect base nano-devices and thin film devices.
Hydrogen passivation was applied to the initial epitaxial growth of n-type β-FeSi2 thin films on p-type Si(111) substrates by facing-targets direct-current sputtering (FTDCS) in order to reduced the formation of interface states and terminate dangling bonds in the β-FeSi2 films, and the passivation effects were studied on basis of the electrical evaluation results of the formed n-type β-FeSi2/p-type Si heterojunction photodiodes. The initial growth was made at different gas inflow H2/Ar ratios ranging from 0 to 0.2. The photodetection performance of the photodiode fabricated at the ratio of 0.2 was markedly improved as compared to those of the other samples. The quantum efficiency and detectivity were 2.08 % and 1.75 × 1010 cm√Hz/W, respectively. The sample exhibited the minimum junction capacitance density of 9.2 nF/cm2. The enhanced photodetective performance should be mainly because dangling bonds that act as trap centers for photocarriers are effectively inactivated by the passivation.
A sudden break-down of a heat-exchanger in vinyl chloride plant resulted in that 141 °C, 23% concentration of hydrochloric acid spouted out over the workers around it. Eight workers suffered and Ichihara City Fire Department was deployed in response to the call 3 minutes after the onset of the incident, 17 vehicles including 5 fire engines, 6 ambulances, and two helicopters. Finally three severely (> 80% of TBSA) burned, two moderately (20–80%) burned, and three slightly (< 20%) burned victims were identified and triaged. One severely burned was transferred at first to the closest tertiary care hospital (TUCMC) which existed within 2.5 km distance by an ambulance and other two and one moderately burned were transferred by helicopters to the neighboring tertiary care hospitals. Another moderately burned one was sent to TUCMC by an ambulance about 30 minutes later than the first one. Three slightly burned victims were sent to a local hospital and treated as an outpatient. This casualty mission was ended by 120 minutes after the call. Two among the three severely burned patients lost their lives but another severe one and two moderately burned were survived. Conclusions: With these considerations, the management of this multiple burn casualty was successful, partly because of small number of the victims and of that the incident occurred in a weekday morning.
Formation of Au colloid particles and their optical property have been investigated in silica glasses implanted with Au+ ions at an acceleration energy of 1.5MeV and fluence levels of 1016-1017 ions/cm2. The Au colloid particles are formed in the as-implanted glasses. It is inferred that the average radius of Au colloid particles depends on the fluence level, although the fluence level does not affect the distribution of Au atomic concentration. The heat-treatment little affects the Au atomic distribution. The Au colloid particles grow to 4.3nm in average radius during heat treatment. It is revealed that the large nonlinear optical property of the Au+ -ion-implanted silica glass is attributed to the high concentration of the Au colloid particles in the narrow region.
Monolithic gels of V2O5, Ta2O5 , and Nb2O5 have been prepared from VO(C2H5O)3 , Ta(C2H5O)5 , and Nb(C2H5 O)5 througg hydrolysis in ethanol Solutions. The conditions for gel formation have been determined. Thin coatings of these gels, less than 100 nm in thickness, have been prepared by dip coating. Changes in the thickness, d, and refractive indices, n, have been measured by ellipsometry during drying. In the first stage of drying, d decreases and n increases rapidly. Densification of the coatings takes place due to evaporation of solvent. In the following stage, increase in d and decrease in n have been observed for thin V2O5 gel coatings, about 30 nm or less in thickness. These results suggest that coarsening of pores and/or increase in surface roughness take place due to release of the capillary pressure during drying. Both d and n have increased with increasing number of dipping. After heat treating, decrease in d and increase in n have been observed.
Fibrous crystals containing the high-Tc phase (2223 phase) of the Bi(Pb)-Sr-Ca-Cu-O superconductor have been prepared by heating a glassy melt-quenched plate in a stream of oxygen gas. Each fiber is composed of several platelike single crystals which are stacked in a layered structure. The fibers show two stepdrops in resistance at 105K and 73K, and a zero-resistance state around 70K. From the results of SQUID measurements, the volume fraction of the high-T phase is found to be about 0.6%. The high-Tc phase is also detected with a microarea X-ray diffractometer, and it is stacked in the interlayer between the low-Tc platelike crystals. For the fibrous Bi-Sr-Ca-Cu-Li-O crystals, the volume fraction of the high-Tc phase increases to 1.5% and a zero resistance state is achieved at 81K. The Jc value of the Li doped fiber is 30,000A/cm2 at 77K and 300,000A/cm2 at 66K in a zero magnetic field.
From the irradiation resistance and high-temperature strength, oxide dispersion strengthened (ODS) ferritic steels are candidate materials for advanced and fusion reactors. For the development of advanced steels the key issue is to homogenize nano-particles into matrix. Recent studies have indicated that Ti addition can homogenize Y-Ti complex particles into ferrite matrix, but the reason of the effect of additional elements has not been clarified. In this model study, we focus on the effect of additional elements, such as IV and V families and other oxide formers, which can control potentially the distribution of the oxide particles. The materials used in this study were based on Fe-9Cr-Y2O3 alloys which were mechanical alloyed (MA) from the powder of Fe, Cr and Y2O3, which was added systematically with the element of Ti, Zr, Ta, V, Nb, Hf, Al, Si and others. Usually ODS fabrication process is required for hot extrusion, but we annealed up to 1150 C for simplify the microstructure. To evaluate the distribution of ODS particles; we used TEM equipped with EDS after electro-polishing or FIB techniques. (1) In the case of Si or Al addition, oxides were disappeared after MA process, which means Y2O3 and other elements should be in solution at non-equilibrium condition. Two types of oxides of Y2O3 and Al2O3 or SiO2 developed after the annealing at 850 C, but only complex oxides were developed after the annealing at 1150 C. This result suggests that the oxide formation is independent process for Y and Si or Al. (2) In the case of Ti addition, oxides also were disappeared after MA process, but developed after annealing at 1150 C. This means that Ti can stabilize complex oxides of Y and Ti, and enhance the fine distribution of the oxides comparing with simple Fe-9Cr-Y2O3 alloy.
Zirconium silicate is an extremely durable materials with the variety of useful optical and electronic properties and broad range of existing and potential applications. Using Density Functional Theory (DFT) in local density approximation (LDA) and generalized gradient approximation (GGA) with plane wave (PW) basis set we have revealed eight new polymorphs of ZrSiO4 within the energy range ∼1 eV above the most stable zircon which have higher and lower density than experimentally known zircon and reidite. Two structures, which have both silicon and zirconium atoms six-fold coordinated, orthorhombic AlTaO4-like (alumotantite) and monoclinic PbWO4-like (raspite), have similar energies at GGA level ∼0.35 eV above reidite and density intermediate between zircon and reidite. Among two low-density structures, which can be potentially revealed experimentally in the nanocrystalline thin films, the orthorhombic CaSO4-like form has energy similar to reidite but much lower density. We also conducted a comparative study of existing ZrO2 and SiO2 polymorphs, which demonstrates the higher accuracy of GGA approach.
Small crystalline particles in the vicinity of the Si/SiO2 interface have been directly observed by high resolution transmission electron microscopy. These crystallites have typical diameters between 20 and 120 Å. Based on the observed interplanar spacings and angles in lattice images, the structure of these particles has been found to match those of cristobalite. Some orientation relationships also appear to exist between these particles and the silicon layer.
Magnetic recording media used today are based on sputtered cobalt alloy films with thicknesses in the order of 50 nm. As recording density is increased, the microstructure of the film must be controlled with increasing level of sophistication to achieve the magnetic properties necessary for good recording performance. Recording density has been increasing at the compound annual rate of 30%, and in recent years at a higher rate. Already, 1 Gb/in2 has been achieved in the laboratory , and 10 Gb/in2 is being contemplated . In order to achieve such densities, microstructural characteristics such as grain morphology, size distribution, crystallographic orientation, and grain separation must be controlled with great precision, and their relationship to magnetic properties must be understood. The paper will describe the effect of sputter process conditions and the selection of magnetic alloys on the film microstructure and describe what might be required to achieve high recording densities. Particular attention will be paid to grain size distribution and grain separation. Grain separation is important for low noise performance of the media. Alloy selection and sputtering conditions can be manipulated to achieve different levels of separation between the grains.
Hydrated glass was prepared by the treatment in an autoclave. Specimen in a good state was obtained under unsaturated water vapor pressure conditions. The obtained glass has an silica-rich hydrated layer and proved to be more durable than the original glass. There are some kinds of hydroxyl species in the hydrated glass and there are some patterns in the depth profile of water, indicating that the rate-controlling process is not a simple diffusion and the hydration process is a complicated reaction depending on the conditions. Water in hydrated glass is tightly bonded and a disintegration of hydrated glass in this study occurs at more than 560°C.