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A consistent description of the hydrogen permeation through metal membrane based on hydrogen chemical potential proposed has been explained in detail. The hydrogen flux is proportional to the PCT factor, fPCT, consistently, which reflects the shape of the pressure-composition-isotherm (PCT curve) of the material. In addition, in view of the PCT factor, fPCT, and the ductile-to-brittle transition hydrogen concentration, DBTC, a concept for alloy design with high hydrogen permeability and strong resistance to hydrogen embrittlement has been proposed. In this concept, it is important to design alloy composition with appropriate PCT curve under the given pressure and temperature condition. As an example, V–9 mol% Al alloy has been designed, which exhibits high hydrogen flux without brittle fracture under given condition. Thus, the new consistent description is useful not only for the understanding of the hydrogen permeation property but also for the alloy design.
The effect of arachidonic acid (ARA) intake on asthma risk is unclear. The objective of the present review was to systematically evaluate available observational studies on the relationship between ARA exposure and asthma risk in children and adults. A PubMed search was conducted on 22 October 2013 and seventy-three publications were checked against predefined criteria for eligibility. To identify additional eligible publications, potentially relevant articles were searched from bibliographies of articles on ARA and asthma. A total of 2924 citations were scrutinised. Finally, fourteen articles were included. A quality assessment was conducted based on the reporting and methodological quality. A meta-analysis was not conducted; therefore, a qualitative assessment is presented. Three high-, two medium- and ten low-quality studies were reviewed. Eleven studies, including two high- and two medium-quality studies, did not find a significant association between ARA exposure and asthma risk. In contrast, one high-quality study indicated a significant trend toward reducing asthma risk in children with decreasing maternal ARA intake (Ptrend = 0·025), and one low-quality study reported a significant trend of increasing asthma risk with higher blood ARA levels (Ptrend = 0·007). In two low-quality studies, asthma patients had significantly lower blood ARA levels than controls (both P < 0·05). These studies did not sufficiently demonstrate any relationships between ARA exposure and asthma risk because of the limited number of studies and their methodological limitations. They seem to suggest that ARA exposure is not consistently associated with asthma risk. Nevertheless, further evidence is required to prove or disprove the association.
Epitaxial (001)-, (116)- and pseudo (103)-oriented Sr0.35Bi2.2Ta2O9 (SBT (0.35/2.2/2.0)) films were successfully grown on (001), (110) and (111) SrTiO3 substrates, respectively. High-resolution X-ray diffraction reciprocal space mapping (HRXRD-RSM) measurements and pole figure measurements clearly indicated that the (116)-oriented SBT (0.35/2.2/2.0) film consisted of two growth domains those c-axis are separated 180° apart in in-plane and pseudo (103)-oriented SBT film consisted of three growth domains those c-axis are separated 120° apart in in-plane. Moreover, lattice parameter measurements indicated that SBT films grew in fully relaxed state.
Whisker-originated short in the self-aligned contact (SAC) W polymetal gate was directly observed for the first time. Short points between gate electrodes and poly-Si plugs in the test structure were identified by emission microscope and cross-sectional TEM samples of those points were made by using focused ion beam (FIB).
Whiskers are formed during high-temperature processing such as LP-CVD SiN. We have proposed that NH3 de-oxidation step inserted in the SiN deposition sequence is effective for suppressing whisker growth.  In this study it was also confirmed that 600°C NH 3 pre-flow improved leakage current between gate electrode and contact plugs.
We have investigated a resist-trimming process for SAL601 chemically amplified negative electron beam resist. Ultra-fine SAL601 resist patterns with a width of 16nm were obtained by an isotropic trimming process in oxygen plasma. This pattern resolution in SAL601 could not be obtained through direct electron beam lithography alone. Using the trimmed electron beam resists, we have successfully fabricated ultra-fine poly-silicon patterns of less than 20nm width. We applied this nanolithography technique to fabricating an ultra-small metal-oxide-semiconductor field-effect-transistor (MOSFET) and revealed that this trimming process is a useful method for nanometer-scale silicon device fabrication.
Ablation lithography is based on the photo-decomposition ablation of polymer materials by excimer laser. It is a self-development process, and accordingly possible to reduce the throughput time and manufacturing cost of TFT-LCD. The major alterations from the conventional photolithography are the resist material and the mask. Developing both the technologies and using an experimental exposure& aligner, we fabricated a TFT pattern on 300 × 400 mm2 glass substrate. The result proves the feasibility of EAL as an high throughput lithography suitable for a-Si TFT.
To describe outbreaks of nosocomial influenza infection with molecular methods and to elucidate the viral linkages among outbreak case patients including both inpatients and healthcare workers (HCWs).
A 180-bed acute and long-term care hospital in Japan.
Retrospective observational study of nosocomial outbreaks of infection with influenza A/H3N2. Together with information about onset dates and vaccination history, we obtained nasopharyngeal swab samples from individuals with cases of influenza or influenzalike illness (ILI). The hemagglutinin genes of the recovered viruses were sequenced and compared, along with those of community-circulating strains, for similarity by phylogenetic tree analysis.
The outbreaks occurred from February 26 through April 3, 2007, during the 2006–2007 epidemic season, and they involved 11 patients and 13 HCWs. The 2 outbreaks involved 2 different genotypes of influenza A/H3N2 viruses. These virus variants were closely related to the influenza strains that were circulating in the community during the same epidemic season.
This study showed the dissemination of highly homologous influenza virus variants among inpatients and HCWs within a short period, as a result of nosocomial transmission. These strains were also similar to influenza strains that were circulating in the community.
Interdif fusion of Al and Ga in a Si modulation doped AlAs/GaAs superlattice was studied by photoluminescence technique. The diffusion coefficient of Al and Ga in the modulation doped superlattice is 1/3 to 1/2 of that of uniformly doped superlattice with the same average Si concentration. The dependence of the diffusion coefficient on the average Si concentration is similar to that of uniform doping.
Temperature dependency of the dielectric property of c-axis-oriented SrBi4Ti4O15 films was investigated in a temperature range from 80 to 400 K. c-axis-oriented epitaxial films with the film thickness of 30 and 140 nm were grown on (100)cSrRuO3//(100)SrTiO3 substrates by metal organic chemical vapor deposition (MOCVD). Increasing lattice distortions along the a- and c-axes with decreasing film thickness was ascertained by XRD reciprocal space mapping. However, capacitance change normalized by the capacitance data at 300 K for with temperature was independent of the film thickness; it increased from 80 to 230 K and contrary decreased with increasing the temperature. Especially, the temperature coefficient of capacitance from 230 to 330 K was almost the same. It indicates that dielectric characteristics of these films for the temperature are independent of the film thickness in the actual use. Moreover, the same mesurement for the 120 nm-thick fiber-textured c-axis-oriented SrBi4Ti4O15 film deposited on the (100)cLaNiO3/(111)Pt/TiO2/SiO2/(100)Si substrate was also investigated. Resultant capacitance change with the temperature was basically the same with that of the epitaxial one, even though the temperature at maximum capacitance value was slightly shifted to lower temperature of 200 K. These data suggest that of capacitance change with the temperature was almost independent of the film thickness and the in-plane orientation.
c-axis-oriented epitaxial SrBi2Ta2O9 ultra-thin films were grown by pulse-gas-introduced metalorganic chemical vapor deposition (pulsed-MOCVD) on (100)SrTiO3 single crystal substrates with atomic scale step structure and their growth behavior was investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Minimum growth unit was found to be “ghalf-unit-cell” of SrBi2Ta2O9. Height of steps and width of terraces observed at SrBi2Ta2O9 film surface were in good agreement with those at SrTiO3 substrate surface. This shape transfer was induced by lattice displacement of SrBi2Ta2O9 along c-direction formed at atomic step on SrTiO3 substrate. In-plane growth of half-unit-cell SrBi2Ta2O9 2D-islands striding across the step walls was observed. It was considered to be a special phenomenon for c-axis-oriented films of layer-structured compounds due to their large crystal anisotropy and/or several times larger half-unit-cell height than single step one of SrTiO3.
The first practical shape memory alloy, NITINOL, has a transformation thermal hysteresis(Hs) of about 30K and a monoclinic martensite structure. The first application of this alloy was a pipe coupling. Although various ideas were proposed on thermal actuators, they were not easily industrialized at least partly because the amount of Hs of the binary Ni-Ti alloy was too large. While the reduction of Hs is not so easy as transformation temperature control, the alloy was improved in terms of Hs through the discovery of new martensite phases. The first Hs reduction was realized in a Ni-Ti-Cu alloy. The copper addition changes the martensite structure to orthorhombic and reduces Hs to 10-15K. The alloy was first applied to a thermal actuator in automobile fog-lamps. Subsequently the R-phase transformation was identified in the binary alloy under the combination of cold working and a heat treatment at relatively low temperatures. Hs was further reduced to 2K in the R-phase transformation. The R-phase transformation is also featured by an excellent fatigue life which reaches one million cycles. The small Hs and long repetition life rapidly widened the application field of shape memory actuators. An expansion of Hs up to 100K was also achieved by a combination of fine dispersion of niobium and cold working. At present, the Hs of the Ni-Ti base alloys ranges from 2K to 100K. An appropriate alloy system can be selected according to applications. The binary alloy has found a wider application field in the super elastic application. In this paper, we summarize the progress in the modification of Hs and present recent applications of each transformation.
The compositional distribution of Co-Cr vacuum evaporated films is investigated using the 59Co nuclear magnetic resonance technique. The dependence of the spin-echo spectra of Co-Cr films and powders on Cr concentration is measured. The spectra of the films evaporated at 260°C are found to be similar to those of powder samples with the Cr concentration of approximately 6 at%, although the Cr concentration of the films is between 10 at% and 24 at%. It is concluded that the Cr concentration of the ferromagnetic regions in Co-Cr films remains at 6 at%, although Cr concentration increased to 25 at%. The spin-echo spectra of the films evaporated at 160°C show that the Cr concentration in ferromagnetic regions is slightly higher than that found in the films deposited at 265 °C. This implies that segregation is less developed in the 160°C films The relationship between the magnetic properties and the segregation is also discussed
This paper reports on studies of the leachability of Co–60 and Cs–137 from simulated LWR radwastes solidified with thermosetting resin and evaluates the effects of chemical fixation on leachability. It is concluded that insolubilization by a nickel-ferrocyanide compound offers an effective chemical fixation of these radionuclides and is a recommended pretreating method for radwastes that are to be solidified.
A simple method, floating zone melting vapor, was used for fabricating nanowires of Si-Ge material. Single-crystalline nanowires were successfully synthesized. TEM images of these nanowires indicated that each nanowire consists of an inner single-crystalline core and an outer layer. An observation using high-resolution transmission electron microscopy (HRTEM) showed that almost all nanowires have a similar growth orientation to the crystalline core: . The coexistence of germanium-self-catalyzed and oxide-assisted mechanisms has also been suggested.
a-/b-axis-oriented epitaxial bismuth layer-structured ferroelectric thin films were epitaxially grown on (101)-oriented oxide with rutile structure. The long-range lattice matching between the ferroelectric layer and the bottom rutile layer, particularly the number of rutile units facing one ferroelectric unit and the surface orientation, were discussed for (100)(010)Bi4Ti3O12//(101)TiO2 structure. Cross sectional transmission electron microscope analysis suggests that seven rutile units lie under one a-/b-axis-oriented Bi4Ti3O12 unit with lower misfit dislocation density comparing to eight rutile units by one Bi4Ti3O12 model. Based on this result, the surface orientation at the interface was simulated to give us an appropriate ion alignment model. The titanium layer in the (101)TiO2 structure is most likely to match with the oxygen layer in the a-/b-axis-oriented Bi4Ti3O12 film.
This paper describes studies on high-quality InN growth on sapphire by RF-MBE. Critical procedures to obtain high-quality InN films were investigated and (1) nitridation process of sapphire substrates prior to growth, (2) precise control of V/III ratio and (3) selection of optimum growth temperature were found to be essential. Detailed structural characterizations by XRD, TEM, Raman scattering and EXAFS indicate that InN films obtained in this study have ideal hexagonal wurtzite structure. FWHMs of ω-2Θ mode XRD and E2(high)-phonon-mode of Raman scattering are as small as 28.9 arcsec and 3.2 cm-1, respectively. True band gap energy of InN is also discussed based on optical characterization results obtained from well-characterized hexagonal InN grown in this study. PbS, instead of InGaAs, was used as a detector for PL study in order to solve the problem coming from the cut-off wavelength of InGaAs detector. Based on these systematic studies on structural and optical property characterizations using high-quality InN, true band-gap energy of InN is suggested to be less than 0.67 eV and approximately 0.65 eV at room temperature. Single-crystalline InN films are also successfully grown on Si substrates by a brief nitridation of the Si substrates. Significant improvement of InN crystal quality on Si substrates by the insertion of an AlN buffer layer is also demonstrated.
La-Ni-O films were deposited at deposition temperature ranging from 250 to 540°C by rf magnetron sputter deposition. The effects of deposition temperature and the following heat-treatment condition on the constituent phases and characteristics of LaNiO3 films were investigated. LaNiO3 phase was obtained at the deposition temperature of 250 and 360°C, while La-rich phase of La2NiO4 was appeared above 540°C. Crystalline phases of resultant films after the following heat-treatment strongly depended on the partial pressure of oxygen gas in ambience, i.e., in case of the heat-treatment at 800°C, diffraction peaks originated from LaNiO3 phase disappeared on XRD patterns in pure nitrogen gas ambience, while impurity peaks of NiO appeared in oxygen-excess (>50%) ambience. As a result, LaNiO3 films with high crystallinity and the same lattice parameter as the bulk one were obtained in the deposition at 360°C followed by the heat-treatment at 700°C in air.
Degradation property of aluminum due to hydrogen is studied. Hydrogen is introduced by electrolysis charge in aqueous solution with addition of 0.1 mass % NH4SCN as a hydrogen recombination poison. The amount of hydrogen and its existing state in the material is analyzed by hydrogen desorption curves measured by the thermal desorption spectroscopy. The hydrogen desorption curves of charged aluminum showed two peaks, one at less than 100 °C and the other around 400 °C. The existing state of hydrogen relate to each peaks are identified as weakly trapped solute hydrogen to vacancy and free hydrogen molecule located in cavities that exists in the bulk of the material. Tensile properties are obtained to determine degradation property of the material due to hydrogen. The effect of hydrogen on degradation of charged aluminum is analyzed in terms of interaction between hydrogen and vacancy or dislocation. Solute hydrogen and cavities are found to affect ductility of aluminum, whereas hydrogen molecule in cavities has no effect.
Cubic GaN is successfully grown on β-Ga2O3 by molecular beam epitaxy for the first time. Prior nitridation of the (100) β-Ga2O3 single-crystal substrate by exposure to electron cyclotron resonance nitrogen plasma causes the formation of a surficial (001) c-GaN layer, upon which homo-epitaxial growth of c-GaN can be achieved by radio-frequency molecular beam epitaxy. The epitaxial relationship is confirmed by electron microscopy to be (001) c-GaN // (100) β-Ga2O3,  c-GaN //  β-Ga2O3, and [1-10] c-GaN //  β-Ga2O3.