Effects of the IVa element addition on the composite-processed superconducting Nb3Sn

The effect of the IVa element addition to the niobium core and that of gallium addition to the matrix on the composition, growth rate and superconducting properties of the composite-processed Nb₃Sn have been studied. The IVa elements added to the niobium core enhance the growth rate of Nb₃Sn, and prevent the grain coarsening of Nb₃Sn. A much larger amount of titanium is incorporated into Nb₃Sn than zirconium or hafnium. T_c shows a slight maximum against the IVa element concentration in the niobium core. J_c at high magnetic fields is more significantly increased by titanium addition than zirconium or hafnium additions. The gallium substitution for tin in the matrix is effective for increasing T_c and J_c in high fields, except for the specimen with Nb-Ti alloy core. The simultaneous addition of hafnium and gallium is most effective for the enhancement of J_c in high fields.     

Mechanical properties of molybdenum neutron-irradiated at a high temperature

Molybdenum specimens prepared by two processes, powder-metallurgy (PM) and electron-beam melting (EB), were irradiated to a fast neutron fluence of 2.74 × 10²⁴n/m² (E_n? 1 MeV) at about 600°C (873 K), and their mechanical properties were studied in detail. It was shown that the degree of irradiation embrittlement in EB-Mo was smaller than that in PM-Mo, which might be caused by stronger grain-boundaries and probably smaller irradiation-hardening in the former. From the relation between the recovery of ductility and microstructural changes in post-irradiation annealed PM-Mo at 800 (1073 K), 1000 (1273 K) and 1200°C (1473 K), it was concluded that the recovery resulted from a decrease of irradiation hardening due to a rearrangement and a disappearance of depleted-zones, dislocation-loops and voids in order with increasing annealing temperature. An anomalous mode of fracture was observed in as-irradiated specimens, which consisted of inhomogeneous deformation, then brittle fracture not at the center but at the root of the deformation neck. This mode was observed in a narrow temperature range near the DBTT. A possible mechanism is discussed.     

Photoinduced superhydrophilic properties of Ti-B binary oxide thin films and their photocatalytic reactivity for the decomposition of NO

Characterizations of Ti-B binary oxide thin films by means of various spectroscopic measurements have shown that Ti-B binary oxide thin films are formed by ultra fine TiO2 nanoparticles. A dramatic decrease in the contact angle of water droplets to 0 degree under ultraviolet (UV) light irradiation and a return to only half of its initial value under dark conditions were observed for the Ti-B binary oxide thin films. Moreover, ultraviolet irradiation of these thin film photocatalysts in the presence of NO led to photocatalytic decomposition of NO into N2 and O2. Especially when the Ti content was low, the size of the primary nanoparticles of the thin films was smaller and the photocatalytic reaction proceeded efficiently with a high selectivity for the formation of N2 and O2 from NO.     

High‐efficiency light‐collection optics for lamp‐based projection TV

Abstract— A new light‐collection optics has been developed that enhances the luminance of projection TV which use lamps as the light source. The conventional optical system consists of an elliptical reflector and a flat‐surface front glass, but these systems cannot sufficiently collect the beams coming from the light source, and they cause loss in the coupling with the light pipe. To solve this problem, we devised a new optical system through a structure of an aspherical reflector and an aspherical front glass. This new optical system concentrates the beams coming from the light source to a smaller point which improves the coupling efficiency. Thus, we have successfully increased the luminance of the projection TV by approximately 10%. This paper reports the design principles of the new optical system and the results of a prototype experiment.     

Informative patches sampling for image classification by utilizing bottom-up and top-down information

In image classification based on bag of visual words framework, image patches used for creating image representations affect the classification performance significantly. However, currently, patches are sampled mainly based on processing low-level image information or just extracted regularly or randomly. These methods are not effective, because patches extracted through these approaches are not necessarily discriminative for image categorization. In this paper, we propose to utilize both bottom-up information through processing low-level image information and top-down information through exploring statistical properties of training image grids to extract image patches. In the proposed work, an input image is divided into regular grids, each of which is evaluated based on its bottom-up information and/or top-down information. Subsequently, every grid is assigned a saliency value based on its evaluation result, so that a saliency map can be created for the image. Finally, patch sampling from the input image is performed on the basis of the obtained saliency map. Furthermore, we propose a method to fuse these two kinds of information. The proposed methods are evaluated on both object categories and scene categories. Experiment results demonstrate their effectiveness.     

Mapping of boreal vegetation of a temperate mountain in China by multitemporal Landsat TM imagery

The Changbai Mountain Natural Reserve (2000 km 2 ), north-east China, is a very important ecosystem representing the temperate biosphere. The cover types were derived by using multitemporal Landsat TM imagery, which was modified with DEM data on the relationship between vegetation distribution and elevation. It was classified into 20 groups by supervised classification. By comparing the results of the classification of different band combinations, bands 4 and 5 of an image from 18 July 1997 and band 3 of an image from 22 October 1997 were used to make a false colour image for the final output, a vegetation map, which showed the best in terms of classification accuracy. The overall accuracy by individual images was less than 70%, while that of the multitemporal classification was higher than 80%. Further, on the basis of the relationship of vegetation distribution and elevation, the accuracy of multitemporal classification was raised from 85.8 to 89.5% by using DEM. Bands 4 and 5 showed a high ability for discriminating cover types. Images acquired in late spring and mid-summer were recognized better than other seasons for cover type identification. NDVI and band ratio of B4/B3 proved useful for cover type discrimination, but were not superior to the original spectral bands. Other band ratios like B5/B4 and B7/B5 were less important for improving classification accuracy. The changes of spectral reflectance and NDVI with season were also analysed with 10 images ranging from 1984 to 1997. Seperability of images in terms of classification accuracy was high in late spring and summer, and decreased towards winter. There were five vegetation zones on the mountain, from the base to the peak: deciduous forest zone, mixed forest zone, conifer forest zone, birch forest zone and tundra zone. Spruce-fir conifer dominated forest was the most dominant vegetation (33%), followed by mixed forest (26%), Korean pine forest (8%) and mountain birch forest (5%).     

Decorrelation of SAR data by urban damages caused by the 1995 Hyogoken-nanbu earthquake

Large part of urban area of around Kobe city were damaged by the 1995 Hyogoken-nanbu earthquake. For detecting the damaged area, the authors computed correlation coefficients from single-look complex ERS-1/SAR data. Two types of correlations, intensity correlation and coherence were computed. Decorrelation was found in the damaged urban built-up area in the data pair of which interval included the earthquake occurrence. The similarity of the decorrelation between the intensity correlation and the coherence indicated that major factor of the decorrelation is closely related to interferometric processes, which results in the change of speckle patterns in the single-look intensity images. A normalized difference was calculated from the correlation coefficients between the data pair including the earthquake occurrence and the pair before the earthquake. The distribution patterns of the pixels for which normalized difference was higher than a threshold showed good correspondence with the result of the ground survey. The result of this study indicates the possibility of detecting urban disasters using the decorrelation of SAR data.     

Creation of 3-D tiny statue by 5-axis control ultraprecision machining

The study deals with the creation of a 3-dimensional (3-D) complicated tiny statue by means of a 5-axis control ultraprecision machining center and a pseudo ball end mill of single crystal diamond. In recent years, 3-D microstructures are required to provide components for micromechanism as well as metal molds and dies. Thus, as an example of complicated 3-D microstructures, a Buddha head of 3 mm in size was created, based on the scanned data of an actual statue. A control program developed in the study enables a diamond tool to feed around the head and to move from the top of the head to the neck not only by 4-axis control but also by 5-axis control to prevent the tool and its holder from colliding with a workpiece. As a result, a tiny Buddha head could be created with high surface quality.     

Molecular imprinting of biotin derivatives and its application to competitive binding assay using nonisotopic labeled ligands

Synthetic biotin-binding polymers were prepared by molecular imprinting. Methacrylic acid (MAA) was copolymerized with ethylene glycol dimethacrylate in the presence of biotin methyl ester (B-Me) in chloroform. Hydrogen-bonding-based complexation of B-Me with MAA generates the binding sites complementary to B-Me after extracting B-Me from the resulting copolymers. Data from NMR titration suggest a one-to-one prepolymerization complex formation of B-Me with MAA in chloroform. A possible complex structure was estimated by docking of the most stable conformers by intermolecular Monte Carlo conformational search under the assumption of a one-to-one association. The selectivity of the imprinted polymers was investigated and an imprinted polymer-based competitive binding assay for B-Me was demonstrated using biotin p-nitrophenyl ester as a nonisotopic-labeled ligand.