Measurement of self-diffusion coefficients in Li ionic conductors by using the short-lived radiotracer of 8Li

For the effective use of short-lived radioactive beams, soon to be available at the Tokai Radioactive Ion Accelerator Complex, the authors have developed a radiotracer method for diffusion studies in solids. The experimental test was performed by the measurement of the diffusion coefficients of Li in a sample of the compound βLiAl using an α-emitting radiotracer of ⁸Li (T_1/2=0.84 s). It was found that the time-dependent yields of the α particles from the diffusing ⁸Li that was initially implanted in the sample could be used as a measure of the diffusivity of the tracer in a nondestructive way. The method was applied to measure the self-diffusion coefficients of Li in βLiGa, and for investigating how the Li diffusion in the Li ionic conductors is affected by the concentration of atomic defects (i.e., the existence of the atomic vacancies of Li and the defects in Ga sites that are replaced by Li).     

Development of fault cause estimation method for distribution line

We are planning to develop the new Advanced Distribution Automation System (ADAS) equipped with optical communication network and sectionalizer with sensor for more grid reliability and efficiency on maintenance operation. The new system is featured with the function of fault cause or damaged part estimation. The new sectionalizer captures the waveform of electrical line surge originated by fault and the system analyzes the waveform for this function. This paper mainly introduces the system configuration of ADAS and an early stage examination of fault cause estimation technology.     

A reduction method of dynamic false contour utilizing the frame‐rate‐control method with suppression of the side effect on PDPs

Abstract— The plasma‐display panel (PDP) is a type of flat‐panel display that can display a high‐quality image. However, when moving images are displayed, annoying disturbances such as false contour noise occurs. This noise is called dynamic false contour (DFC). To achieve a higher‐quality image, DFC has to be reduced. Therefore, a new method to reduce DFC is proposed. To find a way to reduce DFC, a new evaluation value for it has been defined: the evaluation value of dynamic false contour (EVDFC). This value is defined on the basis of a person's subjective evaluation. By applying this value, the cause that generates DFC can be identified. On the basis of these studies, a new method for reducing DFC by applying frame‐rate control (FRC) with suppression of the side effect is proposed. This improved method can be used to provide high‐quality images.     

Study on high performance ice slurry formed by cooling emulsion in ice storage (discussion on adaptability of emulsion to thermal storage material)

This study focuses on an emulsion as a new thermal storage material for ice storage. Two types of emulsions were formed using an oil–water mixture with a small amount of additive. A silicone, light and lump oils were used. The water contents of the emulsions were 70, 80 and 90%. The additive was an amino group modified silicone oil. No depression of freezing point was observed for the emulsions because of their hydrophobic properties. In order to determine the structure of the emulsions, their electrical resistances were measured. Moreover, components of the liquids separating from the emulsions were analyzed. The results indicated that one emulsion was a W/O type emulsion, while the other was an O/W type. Finally, adaptability of the two emulsions to ice storage was discussed, it was concluded that a high performance ice slurry could be formed by the W/O type emulsion.     

Preparation of a crack-free rough titania coating on stainless steel mesh by electrophoretic deposition

TiO₂ (anatase) coating was prepared on stainless mesh by electrophoretic (EPD) process utilizing an isopropyl alcohol (IPA)-based suspension with submicron TiO₂ powder. When the deposition time was 30 s, a smooth thin coating was obtained. It remained crack-free even after sintering. Coating surface morphology was roughened by UV pre-illumination of the suspension. Photocatalytic decomposition of IPA to acetone and resultant electrochemical reaction at cathode during EPD provides heterogeneous deposition.     

Scanning probe microscopy installed with nanotube probes and nanotube tweezers

We have developed well-controlled processes for the growth and manipulation of carbon nanotubes. The relatively thin multiwalled nanotubes were prepared with high purity by arc discharge with a high gas temperature. In the manipulation of nanotubes, the first crucial process is to prepare a nanotube array, so-called nanotube cartridge. We have found the alternated current electrophoresis of nanotubes by which nanotubes are aligned at the knife-edge of a disposal razor. The second important process is to transfer a nanotube from the nanotube cartridge onto a substrate in a scanning electron microscope. Using this method, we have developed nanotube probes and nanotube tweezers that operate in a scanning probe microscope (SPM). The nanotube probes have been applied for observation of biological samples and industrial samples to clarify their advantages. The nanotube tweezers have been demonstrated for their motion in scanning electron microscope and operated to carry a nanomaterial in a SPM.     

Te concentration dependent photoemission and inverse-photoemission study of FeSe1?xTex

We have characterized the electronic structure of FeSe_1−xTe_x for various x values using soft x-ray photoemission spectroscopy (SXPES), high-resolution photoemission spectroscopy (HRPES) and inverse photoemission spectroscopy (IPES). The SXPES valence band spectral shape shows that the 2 eV feature in FeSe, which was ascribed to the lower Hubbard band in previous theoretical studies, becomes less prominent with increasing x. HRPES exhibits systematic x dependence of the structure near the Fermi level (E_F): its splitting near E_F and filling of the pseudogap in FeSe. IPES shows two features, near E_F and approximately 6 eV above E_F; the former may be related to the Fe 3d states hybridized with chalcogenide p states, while the latter may consist of plane-wave-like and Se d components. In the incident electron energy dependence of IPES, the density of states near E_F for FeSe and FeTe has the Fano lineshape characteristic of resonant behavior. These compounds exhibit different resonance profiles, which may reflect the differences in their electronic structures. By combining the PES and IPES data the on-site Coulomb energy was estimated at 3.5 eV for FeSe.     

A study of reactor neutrino monitoring at the experimental fast reactor JOYO

We carried out a study of neutrino detection at the experimental fast reactor JOYO using a 0.76 tons gadolinium loaded liquid scintillator detector. The detector was set up on the ground level at 24.3 m from the JOYO reactor core of 140 MW thermal power. The measured neutrino event rate from reactor on-off comparison was 1.11±1.24(stat.)±0.46(syst.) events/day. Although the statistical significance of the measurement was not enough, backgrounds in such a compact detector at the ground level were studied in detail and MC simulations were found to describe the data well. A study for improvement of the detector for future such experiments is also shown.     

Production of thin graphite sheets for a high electrical conductivity film by the mechanical delamination of ternary graphite intercalation compounds

Herein we propose a production scheme for conductive films composed of thin graphite sheets with high crystallinity and polymeric resin. The crystalline graphite sheets were successfully produced from natural graphite powder by solution-phase synthesis of graphite intercalation compounds (GICs), following a wet planetary-ball milling under mild conditions. The shear forces in the milling pot lead to a peeling of graphite flakes. Taking into consideration the interlayer bonding force, the delamination should be preferentially done from the expanded GICs interlayer rather than intrinsic graphite one. Some composite films derived from the phenolic resin and flaky graphite sheets displayed much higher electrical conductivities compared to the film from the feed graphite particles. We also demonstrate the stage structure of synthetic GICs affected the film conductivity. The composite films made from exfoliated products of ground (around stage IV) GICs exhibited high electrical conductivity with a small amount of the graphite sheets.