Since the discovery of fading X-rays from Gamma-Ray Bursts (GRBs) with BeppoSAX (Piro et al. 1997, Costa et al. 1997), world-wide follow-up observations in optical band have achieved the fruitful results. The case of GRB 970228, there was an optical transient, coincides with the BeppoSAX position and faded (Paradijs et al. 1997, Sahu et al. 1997). These optical observations also confirmed the extended component, which was associated with the optical transient. The new transient are fading with a power-law function in time and the later observation of HST confirmed the extended emission is stable (Fruchter et al. 1997). This extended object seems to be a distant galaxy and strongly suggests to be the host.

The complex radio source Sgr A is embedded in a region near our Galactic Center. The dynamical center of our Galaxy is considered to be Sgr A*, the compact non-thermal radio source. Dynamical mass within ~0.1 pc from Sgr A* has been estimated to be ~ 3×106 M⊙. This places Sgr A* to be a candidate of a massive blackhole (Eckart and Genzel, 1997 and reference therein).

We made a search of quiescent X-ray counterparts of two Gamma-Ray Bursts (GRBs), GRB930131 and GRB940217. These GRBs were detected with BATSE, EGRET, COMPTEL on board CGRO together with the GRB detector on Ulysses spacecraft, then they were localized in small error regions. These observations showed that the bursts were remarkably bright accompanying delayed high energy gamma-rays. ASCA observations have found a single X-ray source for each GRB on the possible location determined with the above instruments.

In the previous work, it is reported that the Spin-Seebeck effect (SSE), which refer to the generation of a spin current from a temperature gradient, can be enhanced by Fe interface treatment. Here, we investigated the Fe thickness (d Fe ) dependency of spin-Seebeck voltage (V SSE ) and mixing conductance (g r ) in Pt/Fe/Bi:YIG/SGGG system. As a result, magnitude of V SSE had a peak at d Fe ≓ 1 ML (monolayer , ≓ 0.3 mm), and also increase of g r was saturated at this point. It suggests that V SSE increase with increasing g r when d Fe is smaller than 1.0 ML. For the case in which d Fe is larger than 1.0ML, however, V SSE decreases due to a spin current decay in Fe layer with a constant g r . These experimental results are consistent with previous theoretical works.

Recently, the issue of sustainable resource management has been increasingly recognized. Economic growth of human activity is associated with a rapid rise in the use of resources in our economy, and society has a potential environmental impact. The UNEP International Resource Panel (IRP) pointed out the importance of decoupling resource use and negative environmental impacts from economic activity (UNEP IRP 2011). In order to optimize the material cycles and increase resource efficiency, material flow analysis (MFA) is a powerful tool to understand the resource consumption and material cycle in the national economy. In this study, we present the results of global material flow analysis of nickel, which is one of the important resources for reducing energy use and CO2 emission in our society, and discuss the importance and possibility of controlling its resource logistics. This study also introduces the challenge of identifying the land-use changes in nickel mining sites by a remote-sensing technique, and knowledge to increase the resource efficiency in metal recycling based on the metallurgical thermodynamic approach. The results indicated the importance of recovery of nickel in recycling policies for end-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies and implementation of designs for recycling/disassembly at the manufacturing phase are needed. Possible solutions include development of sorting processes for steel scrap and introduction of easier methods for identifying the composition of secondary resources. Recovery of steel scrap with a high alloy content will reduce primary inputs of alloying elements and contribute to more efficient resource use.

We describe the current, 9-spacecraft Interplanetary Network (IPN). The IPN detects about 325 gamma-ray bursts per year, of which about 100 are not localized by any other missions. We give some examples of how the data, which are public, can be utilized.

In this study, aluminized, boronized, chromized and siliconized gray cast iron plate specimens were prepared, and their microstructures and tribological properties were investigated. The surfaces of the aluminized, boronized, chromized and siliconized specimens mainly consisted of FeAl, Fe2B, (Cr, Fe)23C6 and FeSi phases, respectively. Also, the surface of the boronized specimen exhibited the highest microvickers hardness of all the specimens. The aluminized, boronized and chromized specimens exhibited friction coefficients as low as the non-coated specimens when sliding against AISI 52100 steel ball specimens in poly-alpha-olefin. In addition, the boronized and chromized specimens exhibited much higher wear resistance than the non-coated specimens.

Using an ab initio density functional theory (DFT), we study thin film electronic properties of topological insulators (TIs) based on ternary compounds of Tl (thallium) and Bi (bismuth). We consider TlBiX2 (X=Se, Te) and Bi2X2Y (X, Y=Se, Te) compounds. Here we discuss the nature of surface states, their locations in the Brillouin Zone (BZ) and their interactions within the bulk region. Our calculations suggest a critical film thickness to maintain the Dirac cone which is smaller than that in binary Bi-based compounds. Atomic relaxations are found to affect the Dirac cone in some of these compounds. We discuss the penetration depth of surface states into the bulk region.

The nodal SDW order parameter on a cylindrical Fermi surface is thought to create the Dirac cone in the metallic ground state of iron pnictides and iron chalcogenides. Confirming appearance of the Dirac cone in DFT-GGA solutions of FeSe, we discuss origin of the bulk SDW order parameter in the stacked two-dimensional electronic system. In a layered system with vanishingly small inter-layer single-particle hopping processes, the exchange channels derived for the inter-plane magnetic interaction is the super-exchange counterpart of the two-particle Coulomb scattering for the pair-hopping channel in the layered superconductivity. The fluctuation reference method of the multi-reference density functional theory concludes existence of the inter-layer super-exchange interaction by the Coulomb off-diagonal elements among orbitals in the semi-metallic band structure. Thus a proof of 2D nature of the third generation Dirac cone in iron pnictides induced by SDW also promotes understanding of the high-temperature superconductivity.

This study determined the prevalence and antimicrobial susceptibility of Salmonella isolated from broiler flocks in Japan. Caecal dropping samples were collected from 288 broiler flocks between November 2007 and February 2010. Salmonella was prevalent in 248 (86·1%) broiler flocks. The top three serovars were S. Infantis, S. Manhattan and S. Schwarzengrund. S. Infantis was found in all regions tested in this study. However, S. Manhattan and S. Schwarzengrund were frequently found only in the western part of Japan. High antimicrobial resistance rates were observed against oxytetracycline (90·2%), dihydrostreptomycin (86·7%) and ampicillin (36·5%), and 258 (90·5%) of 285 isolates were resistant to two or more antimicrobial agents. Interestingly, 26·3% of isolates were resistant to ceftiofur, especially 38·1% of S. Infantis isolates, although its use in broilers has not been approved in Japan. This study showed that Salmonella is highly prevalent (86·1%) in Japanese broiler flocks, that 90·5% of Salmonella isolates were multidrug-resistant, and that S. Infantis frequently exhibited resistance to cephalosporin antimicrobial agents.

Human salmonellosis cases, particularly those caused by Salmonella Enteritidis, have been closely linked to egg consumption. This epidemiological survey was conducted to determine the baseline Salmonella prevalence and identify the risk factors for Salmonella prevalence in laying-hen farms in Japan. Caecal excrement samples and dust samples were obtained from 400 flocks in 338 laying-hen farms. Salmonella was identified in 20·7% of the farms and 19·5% of the flocks. The prevalence of Salmonella was significantly higher in flocks reared in windowless houses than in those reared in open houses. In addition, the risk of Salmonella presence was significantly higher when the windowless house farms implemented induced moulting or in-line egg processing. Efforts to reduce human salmonellosis in Japan should continue to focus on the establishment of control measures in laying-hen farms, especially those with windowless houses implementing induced moulting and equipped with in-line egg processing.

Electroabsorption spectroscopy of well-identified index-defined semiconducting carbon nanotubes is reported. The measurement of high definition electroabsorption spectra allows direct indexation with unique nanotube chirality. Results show that at least for a limited range of diameters, electroabsorption is directly proportional to the exciton binding energy of nanotubes. Electroabsorption is a powerful technique which directly probes into carbon nanotube excitonic states, and may become a useful tool for in situ study of excitons in future nanotube-based photonic devices such as electroabsorption modulators.

Magnetic properties of Co-doped rutile (Ti1-xCoxO2) film in combinatorial composition-spread form have been surveyed by means of a Scanning Superconducting-quantum-interference-device Microscope (SSM). As a consequence, we found magnetic domains in the spatial regions with x>0.05 without external field, giving strong evidence for ferromagnetism with finite spontaneous magnetization. The magnetic moment was monotonously increased with increasing doping level x from 0.05 to ∼ 0.13. On the other hand, it was almost unchanged for x > ∼ 0.13, suggesting that Co does not dissolve into rutile film beyond x ∼ 0.13. The SSM results on the rutile Ti0.95Co0.05O2 thin films with different thickness showed that the magnetic moment is proportional to film thickness, leading to a conclusion that the presently observed ferromagnetism does not result from Co or Co-based oxide particles on the film surface.

Diluted magnetic semiconductor (DMS) possesses charge and spin degrees of freedom leading to their interplay promising for novel devices. DMSs based on II-VI and III-V compound semiconductors have been extensively studied so far. Recently, the oxide semiconductors doped with transition metal magnetic impurity have attracted much attention for the possible high ferromagnetic Curie temperature. Here, we overview recent studies of the transparent oxide based DMSs, ZnO, TiO2, and SnO2 doped with 3d transition metals, by using the combinatorial materials synthesis and the high throughput screening.

In this study, the near-surface regions of air-exposed thin GaN layers deposited by hydride vapour phase (HVPE) epitaxy on 6H-SiC substrates have been examined. Chemical-state identification and in-depth elemental distribution profiles are evaluated using angle-resolved X-ray photoelectron spectroscopy (ARXPS) and secondary ion mass spectroscopy (SIMS). The epilayers show a high degree of chemical purity as determined by XPS and SIMS. Low temperature photoluminescence (PL) were performed and is dominated by donor-acceptor pairs (DAP) emission. Layer thickness was measured to be ∼ 600-700 nm and an abrupt, well-defined heterointerface is observed using scanning electron microscopy (SEM) and SIMS.

The arsenic dose dependence of electrical properties for implanted samples at 500°C and subsequently annealed at 1600°C for 30min has been investigated to derivate the activation energies of the arsenic donors in silicon carbide. Hall effect measurements were performed between 20K and 773K. Hall carrier concentration of implanted sample with high dose of 7×1015 cm−2 is independence of temperature, which indicates the formation of implanted layer with metallic conduction. For the sample with low dose of 1×1014 cm−2, the experimental Hall mobility varies directly as T3/2 below 80K and as T−3/2 above 150K. The activation energies of arsenic donors determined from the implanted sample with low dose using a least-squares fit of the charge neutrality equation are 66.8 meV for hexagonal site and 127.0 meV for cubic site, respectively.

n-type 3C-SiC was heteroepitaxially grown on n-type Si(100) substrates using HMDS (hexamethyldisilane) and characterized by DLTS (deep level transient spectroscopy) measurements. In order to investigate relationship of defect density with epilayer thickness, epilayers with various thicknesses were grown. Relatively thin (<1.0μm thick) epilayers were found to contain defects with energy levels distributed in a wide energy range, while relatively thick (>2.2μm thick) epilayers contain a defect with an activation energy of 0.25eV. This defect level is slightly shallower than that in 3C-SiC grown by SiH4 and C3H8 (∼0.3eV).