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Continuum observation of galaxies in millimeter-wave gives informations on dust emission from molecular clouds, free-free emission from HII region and synchrotron emission from SNR and diffuse component. The free-free emission can be observed only at millimeter-wave frequencies and their emission is optically thin, it can be a good indicator of their star-formation activities.
Using a newly developed rapid test, an outbreak of human metapneumovirus (HMPV) infection in a long-term care facility was detected within only 2 days after the onset of symptoms in a putative index case. The outbreak was almost under control within 8 days mainly by zoning patients, with the exception of two cases of HMPV that were diagnosed 16 and 17 days after the onset of the outbreak. According to an immunological diagnosis as well as the rapid test, it was eventually proven that 18 patients had HMPV infections. We suspected that even asymptomatic residents, who had not been completely separated from the facility population, were a source of infection. That suggested that all asymptomatic residents should be tested and that the separation of the infected patients should be absolute, if an outbreak of HMPV infection is suspected in such a facility.
To apply thin ZnO film to photoacoustic tomography sensors, we investigated methods to improve its piezoelectricity with high optical transmittance. ZnO film was deposited by RF magnetron sputtering on a quartz substrate with various changes of the following conditions: RF sputtering power, Ar gas pressure, and substrate temperature (TSUB). The preliminary optimization of sputtering conditions is to form the ZnO film with good c-axis crystalline alignment. The results of X-ray diffraction measurement and cross-sectional observations indicated that the high-TSUB condition was preferable. This was because the desorption of Zn due to high-TSUB during the deposition process induced the formation of excellent columnar grains normal to the substrate. To enhance the piezoresponse, the substitution of Zn with different crystal-radius atoms was investigated, the aim being to increase the electrically neutral dipole moment by the partial displacement of the Zn-O bond. The transition metal V, with the potential to have the various configurations and coordination numbers, was selected as the dopant. As a result, it was confirmed that the diffraction peak from the (002) plane shifted to low angles with small degradation of the diffraction intensities.
This study aimed to investigate the function of tissue plasminogen activator in the olfactory epithelium of mice following neural injury.
Transmission electron microscopy was used to study the changes in the morphology of the olfactory epithelium 1–7 days after surgical ablation of the olfactory bulb (bulbectomy).
Prior to bulbectomy, a uniformly fine material was observed within some regions of the olfactory epithelium of mice deficient in tissue plasminogen activator. At 2–3 days after bulbectomy, there were degenerative changes in the olfactory epithelium. At 5–7 days after bulbectomy, we noted drastic differences in olfactory epithelium morphology between mice deficient in tissue plasminogen activator and wild-type mice (comparisons were made using findings from a previous study). The microvilli seemed to be normal and olfactory vesicles and receptor neuron dendrites were largely intact in the olfactory epithelium of mice deficient in tissue plasminogen activator.
The tissue plasminogen activator plasmin system may inhibit the regeneration of the olfactory epithelium in the early stages following neural injury.
Cluster ion implantation is an attractive alternative to conventional ion implantation, particularly for shallow junction formation. It is easy to obtain high-current ion beams with low equivalent energy using cluster ion beams. The implanted boron distribution in 5keV B10H14 implanted Si is markedly shallower than that in 5keV BF2 ion implanted Si. The implanted depth is less than 0.04 μm, indicating that cluster ion implantation is capable of forming shallow junctions. The sheet resistance of 3keV B10H14 implanted samples falls below 500 Ω/sq after annealing at 1000°C for 10s. Shallow implantation can be realized by a high energy cluster beam without space-charge problems in the incident beam. Defect formation, resulting from local energy deposition and multiple collisions, is unique for cluster ions. The thickness of the damaged layer formed by cluster ion bombardment increases with the size of the cluster, if implant energy and ion dose remain constant. This is one of the nonlinear “cluster effects,” which may allow some control over the implant damage distributions that accompany implanted ions, and which have been shown to have a great effect on dopant redistribution during annealing
This article describes design of fullerene-based electron-accepting materials to obtain high performance in organic thin-film photovoltaic devices. A 1,4-bis(dimethylphenylsilylmethyl)fullerene gives higher open circuit voltage than 1,2-diadduct because of smaller π-conjugated systems, and enables columnar fullerene-core array for high electron mobility and thermal crystallization for ideal phase separation with electron-donor materials. A 56π-electron fullerene derivative possessing the dihydromethano group as the smallest carbon addend does not disrupt fullerene-fullerene contact in solid state, giving high open-circuit voltage without decreasing of short-circuit current density and fill factor.
Molecular Dynamics (MD) and Metropolis Monte-Carlo (MMC) models of monomer B and decaborane implantation into Si and following rapid thermal annealing (RTA) processes have been developed in this paper. The implanted B dopant diffusion coefficients were obtained for different substrate temperatures. The simulation of decaborane ion implantation has revealed the formation of an amorphized area in a subsurface region, much larger than that of a single B+ implantation, with the same energy per ion. The B diffusion coefficient shows an unusual temperature dependence with two different activation energies. Low activation energy, less than 0.2, was obtained for a low-temperature region, and a higher activation energy, ˜ 3 ev, for a higher-temperature region which is typical for the RTA processing. The higher activation energy is comparable with the equilibrium activation energy, 3.4 ev, for B diffusion in Si.
The method of ion implantation and spike annealing for preparing shallow junctions suitable for the extension regions bridging the channel and source/drain contacts of CMOS transistors are studied by annealing blanket implants. Junction depths at a given sheet resistance for low energy B implants are minimized for the combination of a fast ramp with a sharp-spike anneal. This is shown to be physically based on activation energy phenomenology. The fraction of electrically activated B is insensitive to implant dose, unlike the case of transient enhanced diffusion. Arsenic implants show higher activation fraction than comparably annealed P implants, without the large transient enhanced diffusion which is attributed to P and Si-interstitial coupled diffusion. For targeted sheet resistance and junction depth, spiking temperature trends lower with implant dose, concomitant with decreasing fraction of activated dopant.
Understanding the diffusion and activation of arsenic is critical for the formation of low resistance ultra-shallow junctions as required for nanoscale MOS devices. In this work, we use results of ab-initio calcultions in order to gain insight into the fundamental process involved in arsenic activation/deactivation. Utilizing continuum modeling, we find it is possible to account for both the very rapid initial deactivation of arsenic as well as the strongly superline independence of interstitial supersaturation on doping level which accompanies deactivation. The critical process is the rearrangement of A s-atoms via in testitial mediated diffusion leading to ejection of silicon atoms from arsenic complexes and formation of arsenic-vacancy clusters.
Unidirectional solidification of Ti-48Al binary alloy using γ-TiAl single-phase seed crystals has been carried out by an optical floating zone method. The lamellar orientation of the grown PST crystal follows the orientation of the Ti-57Al seed crystal, while it fails to follow that in the case of the Ti-53Al seed. Microstructure analysis reveals that the seed crystal of Ti-57Al exhibits a flat liquid/solid interface in melting (γ→+L) even after making contact with 48Al to grow, whereas the seed of Ti-53Al shows a cellular interface due to the peritectic reaction in melting (γ→α+L). At the 57/48 interface, an abrupt change of Al concentration was detected from the seed to the grown crystal, indicating an occurrence of composition travel to skip the peritectic reaction, which is responsible for the control of lamellar orientation of the grown PST crystals. The same attempt has been made by using the 57Al single crystal seed with a different orientation, and the lamellar orientation of the grown PST crystal was confirmed to follow the orientation of the seed.
Initial studies (using Scanning Spreading Resistance Microscopy) on the lateral diffusion of B and As have shown an important influence of the thickness of oxy/nitride spacers. The latter phenomenon was tentatively ascribed to stress enhanced diffusion under the spacer region . These studies have been complemented with Scanning Capacitance Microscopy (SCM) measurements, which confirm the SSRM-data. In fact both techniques shows a similar increase in lateral diffusion with increasing spacer thickness (∼ 0.2 nm/nm spacer thickness), whereby no effect is observed on the vertical diffusion. When using spacers with or without TEOS-liner, fairly similar enhancements could be seen. Micro-Raman and CBED stress measurements for these cases do however show a large reduction in stress when a TEOS-liner is used, suggesting that the correlation (at least to the final) stress is not really justified. A possible explanation could however be that the lateral diffusion occurs before the stress relaxation within the thermal treatment. In order to elucidate the diffusion mechanism (initial stress, interstitials, hydrogen incorporation, TED,..) we have expandedthe experimental matrix with a vacancy diffuser such as Sb and simulated the potential H-incorporation duringthe nitride deposition by a hydrogen anneal. Moreover we also have studied the impact of TED by splits with RTP-anneals before the nitride deposition.
Phase equilibria among γ-Fe, ε-Fe2Nb Laves and δ-Ni3Nb phases in Fe-Ni-Nb ternary system at 1473 K and 1373 K were experimentally examined, and also assessed by calculation in order to calculate the phase equilibria among these phases at 973 K. A ternary compound with hP24 structure with its limited composition range of Fe-21.5Nb- (56.8-59.8) Ni exists between Fe2Nb and Ni3Nb phase regions at both temperatures. Including the hP24 phase, the calculated isotherms at both temperatures are in good agreement with experimental ones. By using the optimized interaction parameters among the three elements in each phase, the isothermal section calculated at 973 K revealed a γ-Fe+ Fe2Nb + Ni3Nb three-phase coexisting region extended to Fe-rich composition of 80 at. % Fe. This suggests a possibility to develop austenitic heatresistant steels strengthened by both intermetallics phases.
We report the fabrication of complex 3D microstructures in silica and polymethyl- methacrylate glass by a combination of femtosecond laser microfabrication and chemical wet etching techniques. It is demonstrated that fabrication of interconnected network of channels having lengths of about 200 νm, and diameters as small as 10 νm is possible due to the enhanced etching selectivity (typically 20 - 60) in the laser-irradiated regions. Thus, it becomes feasible to form 3D micro-fluidic and photonic crystal structures in transparent glass-like materials using this approach. In addition, preliminary results on microstructuring of rubber are presented.
A Microstructurally controlled γ(TiAl)-based alloy containing β(bcc) has shown remarkable tensile properties at high temperatures. It exhibits over 450% tensile elongation at 1473K. The strain rate sensitivity factors are calculated to be over 0.3 above 1273K. A specific texture is not observed from transmission X-ray photograph. TEM observation reveals that the precipitated β phase located at grain boundaries elongates uniformly along γ grain boundaries and causes large ductility. We propose β/γ dual phase alloys as high temperature deformable materials.
Rutherford backscattering (RBS) analysis of small-sized structures, fabricated by laser chemical vapor deposition (LCVD) with a focused laser beam and ion implantation with a focused ion beam (FIB), has been performed by a microprobe with focused 1.5 MeV helium ions. Micro-RBS spectra and RBS-mapping images revealed a local distribution of masklessly deposited Mo layers on GaAs and local doses of masklessly implanted Au atoms in Si.
Gas cluster ions contain tens, hundreds or even more than thousands of atoms or molecules as ionized particles. It has been shown that the bombarding effects of gas cluster ions on solid surfaces are quite different from those by monomer ions and involve unique material processing characteristics. In order to make clear the bombarding effects, a study of surface modification of sapphire by Ar and CO2 gas cluster ion beams has been performed.
Thickness of the damaged layer and surface roughness produced on sapphire depends strongly on cluster ion energy. Damage layer thickness on a sapphire surface bombarded by 150 keV clusters with average size of about 3000 atoms was 40Å. No significant difference was observed in IR transmittance after cluster bombardment. Mechanical properties of sapphire surfaces can be changed by cluster irradiation at a dose of 1011 ions/cm2.
Gas cluster ion beam equipment (max. voltage 30kV) for sputtering has been developed. Cluster ion beams from gaseous materials such as Ar, O2, N2 and compound materials such as SF6, N2O, CO2 can be generated by expanding them through a Laval nozzle into a high-vacuum region. With this equipment sputtering process fundamentals have been studied. One of the unique characteristics of gas cluster ion bombardment is lateral sputtering. This is shown experimentally by measuring the angular distribution of sputtered atoms and is predicted by molecular dynamics simulation. Dependencies of sputtering yield (10-1000 times higher than for the monomer ion case) on cluster ion size and on ion beam energy for different substrate surfaces have been obtained. Examples of surface smoothing (typically less than 1 nm average roughness) on metals, semiconductors and insulators and of surface cleaning are presented.
The Re oxide films were deposited on quartz glasses by RF reactive sputtering from a Re metal target. The lowest resistivity was observed in the film in-situ annealed at 200°C in Ar atmosphere and showed the order of 10-4 Ω cm of which the value was still about 10 times as large as that of a single crystal ReO3. The temperature dependence of the resistivity revealed a metallic behavior. A superconductivity did not take place in the bilayered film of ReO3 / NdBa2Cu3O6. In the interface region the resistivity minimum probably caused by the Kondo effect was observed in the neighborhood of 120K.