Search

The Japan Atomic Energy Agency has been developing 9Cr-oxide dispersion strengthened (ODS) steel as a fuel cladding material for sodium-cooled fast reactors (SFRs). Previous studies have formulated the creep rupture equation for 650°C–850°C. However, little data have been obtained above 850°C, and no equation has been formulated. This study conducted creep tests to evaluate creep strength at 700°C–1000°C. Two creep test methods, the internal pressure and ring creep tests under development, were used, and the validation of the ring creep test method was conducted. The results showed that 9Cr-ODS steel undergoes almost no strength change due to the matrix's phase transformation, and a single equation can express a creep rupture strength from 700°C to 1000°C. In validating the ring creep test method, analysis clarified the effect of stress concentration on the specimen. Plastic deformation occurs at high initial stress and may lead to early rupture. The results will be essential for future creep testing and evaluation of neutron-irradiated 9Cr-ODS steel. [ABSTRACT FROM AUTHOR]

Metal-carbon composites have recently gained attention as potential hydrogen storage materials. In the present investigation, carbon blacks (CBs) with 0.6 mass %, 4.9 mass %, and 9.3 mass % of Pd were prepared to investigate the cooperative effect together with Pd and CB for hydrogen storage. The hydrogen adsorption isotherms were measured at 77 K, 98 K, 123 K, 148 K, 173 K, 223 K, and 273 K under mild pressures below 1 MPa. The lower temperature gave the higher hydrogen content. Almost all the hydrogen contents of Pd-modified CBs exceeded the sum of the adsorption contents of CB and the occluded amounts of the assumed hydride, PdH0.6. The highest hydrogen content was recorded for Pd 0.6 mass %-modified CB at 77 K. At temperatures above 77 K, CBs with the higher Pd contents adsorbed more hydrogen than Pd 0.6 mass %-modified CB, and they indicated an increase in the absolute values of adsorption enthalpy with the progress of adsorption. Pd was thought to be at first blocking deep potential sites, with accessibility to hydrogen acceptable sites gradually increasing as adsorption progressed. [ABSTRACT FROM AUTHOR]

This study aimed to investigate whether anticipatory cardiorespiratory responses vary depending on the intensity of the subsequent exercise bout, and whether anticipatory cardiorespiratory adjustments contribute importantly to enhancing exercise performance during high‐intensity exercise. Eleven healthy men were provided advance notice of the exercise intensity and a countdown to generate anticipation during 10 min prior to exercise at 0, 50, 80 or 95% maximal work‐rate (Experiment 1). A different group of subjects (n = 15) performed a time to exhaustion trial with or without anticipatory countdown (Experiment 2). In Experiment 1, heart rate (HR), oxygen uptake (VO2) and minute ventilation (VE) during pre‐exercise resting period increased over time and depended on the subsequent exercise intensity. Specifically, there was already a 7.4% increase in HR from more than 5 min prior to the start of exercise at 95% maximal work‐rate, followed by progressively augmented increases of 12.5% between 2 and 3 min before exercise, 24.4% between 0 and 1 min before exercise. In Experiment 2, the initial HR for the first 10 s of exercise in the task with anticipation was 11.4% larger compared to without anticipation (p < 0.01), and the difference in HR between the two conditions decreased in a time‐dependent manner. In contrast, the initial increases in VO2 and VE were significantly lower in the task with anticipation than that without anticipation. The time to exhaustion during high‐intensity exercise was 14.6% longer under anticipation condition compared to no anticipation (135 ± 26 s vs. 119 ± 26 s, p = 0.003). In addition, the enhanced exercise performance correlated positively with increased HR response just before and immediately after exercise onset (p < 0.01). These results showed that anticipatory cardiorespiratory adjustments (feedforward control) via the higher brain that operate before starting exercise may play an important role in minimizing the time delay of circulatory response and enhancing performance after onset of high‐intensity exercise in man. [ABSTRACT FROM AUTHOR]

Ocean sludge seriously exerts significant environmental load to local sea areas and has a negative effect on the marine ecosystem. In this study, the use of fine-bubble technology for the purification of sludge is being investigated. The principle behind this technology is that the bacteria that can degrade sludge are activated by the aerobic conditions induced by the fine-bubbles. Fortunately, one of the authors successfully developed a fine-bubble decomposition system (circulation type) for ocean sludge. Hence, to verify and check the system’s performance it was used and tested in the treatment of sludge that was obtained from Manila Bay and from Funabashi and Hidaka ports, in Japan. Interestingly, the results of the study showed that the system performed very well in treating the sludge. It is noteworthy to mention that through this study, potentially beneficial bacteria isolated from the sludge sample was successfully identified using 16S rRNA gene sequence analysis. [ABSTRACT FROM AUTHOR]

Polluted sludge from the Pasig River generally exerts a very large environmental load to the surrounding area near the vicinity of Laguna de Bay and Manila Bay in the Philippines. Historically, the river was used to be a good route for transportation and an important source of water for the old Spanish Manila. However, the river is now very polluted due to human negligence and industrial development, and biologists consider it unable to sustain aquatic life. Many researchers have conducted studies on the Pasig River, unfortunately, no considerable progress from the point of view of purification process have succeeded. Hence, in this study, the use of fine-bubble technology for the purification of the polluted sludge from the said river is being explored. The critical point in using this technique is on the activation of the bacteria existing in the area using fine bubbles. The sludge is decomposed and purified by activating the aerobic bacteria after creating an aerobic state. In this study, the main objective is to test the performance of the purification system on the sludge and water taken from the Pasig River by comparing the results with the case study conducted in Funabashi Port, Japan. Based on the results of the study, it was established that the use of a circulation-type purification system is very good for it significantly decreased the total nitrogen in the samples from the Pasig River and Funabashi Port. Generally, the said system is considered effective in treating and purifying ocean or river sludge. [ABSTRACT FROM AUTHOR]

DNA coating on dental titanium (Ti) implants is attracting attention due to its osteogenic properties. The aim of the present study was to evaluate in vitro and in vivo bioactivities of a multilayered DNA/protamine (D/P) coating on Ti implant by simulated body fluid (SBF) immersion experiments and implantation experiments into extracted sockets of rat molars. Two types of DNA, 300 base pair (bp) and 7000 bp fragments, were used. Protamine was initially immobilized onto Ti implants using a tresyl chloride-activated method and DNA and protamine were then alternatively deposited after the immobilization of protamine by a layer-by-layer technique. A multilayered D/P-coating was confirmed by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy measurements. The deposition of apatite progressed more on the surfaces of multilayered D/P-coated Ti implants than on those of nontreated Ti implants in SBF immersion experiments. Animal implantation experiments showed that multilayered D/P-coated Ti implants provided a significantly higher bone-to-implant (BIC) contact ratio 3 weeks after implantation. No significant difference was observed in the BIC ratio 9 weeks after implantation. The results of the present study demonstrated that a multilayered D/P-coating promoted new bone formation at the early stages of the bone healing process. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1500-1509, 2016. [ABSTRACT FROM AUTHOR]

Four kinds of ZrVFe alloys with the C14 Laves phase structure had high hydrogen storage capacity under mild pressures, and those alloys would be promising for widespread application such as recovery of hydrogen derived from water splitting. Addition of titanium to ZrVFe lowered hydrogen desorption temperatures through increase of equilibrium pressures. Substitution of ferrovanadium for vanadium did not deteriorate hydrogen occlusion performance of ZrVFe, and provided with lower cost alloys. Another way to reduce the cost would be elimination of purifying step of vanadium prepared by the thermite process, but remaining aluminum proved to bring about lower hydrogen capacity, as evidenced by comparative experiments including a ZrVFe alloy with aluminum intendedly added. Every alloy had fairly good cycling durability except the one contaminated with aluminum. [ABSTRACT FROM AUTHOR]

Thin carbonate-containing hydroxyapatite (CA) films coating partially stabilized zirconia (Y-TZP) were prepared (CA-Y-TZP) to establish a metal-free implant system. CA was coated using a molecular precursor method. The CA film was deposited on the surface of Y-TZP using a precursor solution, which was a mixture of a calcium-ethylenediaminetetraacetic acid (EDTA) complex and phosphate compounds. The deposited CA film was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy measurements. A focus ion beam system technique revealed that the thickness of the CA film was less than 1.0 µm. Biological evaluations of CA-Y-TZP were performed by immersion experiments in simulated body fluid (SBF) and implantation experiments in the tibiae and femoral condyles of rabbits. In the SBF immersion experiment, apatite deposition progressed more on CA-Y-TZP at the early stage of immersion than on Y-TZP without the CA coating. Animal experiments revealed that bone formation on CA-Y-TZP was similar with than on Y-TZP. Histomorphometrical evaluations showed a significantly higher bone-to-implant contact ratio and bone mass on CA-Y-TZP after implantation into the femoral trabecular bone of rabbits. Therefore, CA-Y-TZP appears to be applicable as a metal-free implant. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1277-1288, 2014. [ABSTRACT FROM AUTHOR]

Abstract: The use of micro-arc oxidation titania (MAO TiO2) coatings to modify titanium surfaces improves the biocompatibility of implant surfaces. To obtain hydrophilic MAO TiO2 coating surfaces electric polarization, which induces surface electric fields in the materials and produces surface charges, was performed in this study. Electric polarization of the MAO TiO2 coatings was confirmed by measuring the thermally stimulated depolarization current. After electric polarization treatment the MAO TiO2 coatings did not exhibit any obvious changes in surface roughness, morphology, or phase components. X-ray photoelectron spectroscopy results indicated that electric polarization resulted in oxidation of the cathodic-faced surfaces and reduction of the anodic-faced surfaces. This result suggests that the existence of a concentration gradient of oxide ions/oxygen vacancies produced the stored space charge in the coatings. Reduction of the deionized water contact angle on the polarized MAO TiO2 surfaces was maintained for longer periods compared with the non-polarized surface. Our study demonstrated that metastable electric fields across the MAO TiO2 coating produced by electric polarization made it durably wettable by reducing the interfacial surface tension between the material and water. [Copyright &y& Elsevier]

Abstract: This paper reports on the effect of the amount of Li+ and Sr2+ ions added to a red-emitting phosphor (CaS:Eu2+, Pr3+) on afterglow time upon visible-light irradiation. The afterglow time of CaS:Eu2+, Pr3+ phosphor with Sr2+ ions (initial Sr/Ca atomic ratio of 0.10) was longer than that of the phosphor without Sr2+ ions by 20min. Moreover, the afterglow time of the Ca0.9Sr0.1S:Eu2+, Pr3+ phosphor with Li+ ions increased with an increase in the initial Li/Ca atomic ratio and was 146min for an initial Li/Ca atomic ratio of 0.04. The lattice strain of the phosphor with both Sr2+ and Li+ ions showed a minimum value for this synthetic condition. The trap depths resulting from Li+ ion addition increased by about 0.145eV. By adding both Li+ and Sr2+ ions to the CaS:Eu2+, Pr3+ host, it was possible to improve the afterglow time. [Copyright &y& Elsevier]

Materials that exhibit the photo-induced magnetic-phase transition of titania are receiving significant attention because they can be easily switched between diamagnetism and paramagnetism by UV irradiation. However, it is difficult to store photo-induced titanium (Ti3+) in air because of its easy oxidation upon oxygen exposure. In this study, titania/polycarbonate hybrid films were prepared using linear 1,6-hexanediol (PHMCD), cyclic 1,4-cyclohexanedimethanol (PCHCD), or their copolymerized carbonate oligomers using the sol–gel method. The oxygen permeability of the hybrid film decreased as the ratio of the ring structure increased by a factor of approximately 32 from PHMCD with only the chain structure to PCHCD with only the ring structure. These hybrid films can generate Ti3+ under a UV irradiation of 250 W for 2 h, and the difference in oxygen permeability significantly affected the lifetime of the Ti3+ by a factor of up to 120. In addition, the tensile tests and IR measurements demonstrated that UV irradiation had little effect on the mechanical intensity and matrix chemical structure. Moreover, the magnetic susceptibility of Ti3+ present in PCHCD was confirmed to be 6.2 (10−3 emu/g(titania)) under an external magnetic field of 5 T induced using a superconducting quantum interference device. [ABSTRACT FROM AUTHOR]

Atom-probe technique was applied to analyze three-dimensional dopant distribution in Si substrate of metal-oxide-semiconductor field effect transistor (MOSFET) structure. As a result, three-dimensional As atom distribution implanted in Si was obtained. The quantification of the As atom distribution in a depth direction was confirmed as compared with the one-dimensional distribution measured by secondary ion mass spectroscopy. Moreover, monolayer segregation of As atoms at the interface between gate oxide and Si substrate was clearly observed. This result shows the possibility to clarify discrete dopant distribution in Si substrate related to the characteristic variation of MOSFETs. [ABSTRACT FROM AUTHOR]

Stable structures of hydrogen atoms trapped in a divacancy in tungsten and their binding energies are presented on the basis of first-principle calculations. The hydrogen atoms are favorable sitting in the vicinity of octahedral interstitial sites (O-sites) next to the divacancy. Besides, hydrogen atoms preferentially occupy O-sites located in the center of the divacancy. As hydrogen atoms increases, O-sites located in the periphery of the divacancy are also occupied by the hydrogen atoms. The divacancy in tungsten is energetically unstable, compared with two isolated monovacancies. However, the divacancy is extremely stabilized by the hydrogen atom trapping. The binding energy of the divacancy depends on the sort of the hydrogen isotope. [ABSTRACT FROM AUTHOR]

Abstract Preparation of Eu3+ doped SrAl 12 O 19 phosphor (SrAl 12 O 19 ：Eu3+) using the sol-gel method is described. The effect of the initial Eu/Sr atomic ratio and the reaction temperature on the fluorescence properties of SrAl 12 O 19 ：Eu3+ was investigated. Powder X-ray diffraction was used to characterize the synthesized products and the optical properties were studied by photoluminescence spectrum. From the obtained phosphor, red luminescence resulting from the 5D 0 → 7F 2 transition of the Eu3+ ion as the luminescence center was confirmed. The luminescence properties of SrAl 12 O 19 ：Eu3+ have been investigated by different initial Eu/Sr atomic ratio and optimum atomic ratio of as synthesized phosphors was 0.04. The host crystal synthesized at under 1000℃ was amorphous and at 1100℃ showed crystalline. From the results of EDX, it was confirmed that each element was uniformly dispersed in SrAl 12 O 19 ：Eu3+. In addition, no change in the proportion of the components in SrAl 12 O 19 ：Eu3+ due to the rise in the firing temperature was confirmed. The emission intensity of the crystalline SrAl 12 O 19 ：Eu3+ was lower than that of the amorphous SrAl 12 O 19 ：Eu3+. This was because the excitation spectrum changed with the crystallization of SrAl 12 O 19. These suggested that crystalline of SrAl 12 O 19 affected for fluorescence properties of the obtained phosphor. [ABSTRACT FROM AUTHOR]

Three-dimensional dopant distributions in actual n- and p-channel metal–oxide–semiconductor devices of 65 nm node in two kinds of commercially available products were investigated by atom probe tomography (APT). Detailed and quantitative dopant distributions in gate, gate oxide, and channel regions were successfully obtained by APT. In particular, similarities as well as differences in the dopant distributions of these two devices, which were made by different fabrication processes, were clarified in detail by estimating the dopant concentrations in the grain, at the grain boundary, and at the interface of the polycrystalline Si gate individually. [ABSTRACT FROM AUTHOR]

In order to enhance hydrogen storage capacity of carbonaceous materials through metal modification, FeNiCr-carbon composites were prepared by calcination of Fe, Ni and Cr-containing polyacrylonitrile (PAN) fibers fabricated by electrospinning method. Fe (III), Ni (II) and Cr (III) acetylacetonates (M (acac) n ) were selected as metal sources. Increase of specific surface area and formation of micropores were observed on heat decomposition of M (acac) n particularly through introduction of steam. Maximal hydrogen content, 1.62 mass%, was obtained at 77 K under 0.8 MPa of hydrogen for a FeNiCr-carbon composite, which contained about 15.5 mass% of metals and had specific surface area of 501 m 2 g −1 . The hydrogen content exceeded the hydrogen physisorption limit, 2.34 mass% per 1000 m 2 g −1 , which was calculated on the basis of the commensurate–incommensurate transition with an enhancing factor ρ of 1.126. After hydrogenation at 653 K, no hydrogen desorption peaks were observed for FeNiCr powders derived from M (acac) n , and one peak at 828 K for a carbonaceous sample prepared from unmodified PAN fibers. From the most promising FeNiCr-carbon composite, another peak was recorded at 752 K in addition to the peak at 828 K. The former would be originated from hydrogen on novel sorption sites additionally created on the composite formation. [ABSTRACT FROM AUTHOR]