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No. 34 MAR. 2016
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<Feature-Ⅰ>Infrastructure systems -In pursuit of safety and security-
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Advanced Techniques for Analyzing Corrosion Resistance of Steels for Infrastructure
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Dr. Takenori NAKAYAMA
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This paper reviews methods for quantitatively measuring the composition of steel rust by X-ray diffraction using internal standards. Also introduced is a method for evaluating the size of rust particles on the basis of molecular adsorption. Experiments with artificially synthesized rust described here suggest new approaches to improve the corrosion resistance of steels. The atmospheric corrosion phenomena of steels used for infrastructures have been analyzed using the ultra-bright synchrotron radiation generated by SPring-8 and the neutron beam generated by a compact neutron source by RIKEN.
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Steel Plate for Bridges with Long-life Coating (Eco-View)
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Dr. Fumio YUSE, Masahiro MATSUSHITA, Manabu IZUMI
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Kobe Steel has developed new steels which were designed to reduce the life cycle cost of bridges. The newly developed steel plates (Eco-View) showed excellent corrosion resistance in 10-year-exposure test results. The anti-corrosion properties of this newly developed steel (Eco-View), after painting, are better than those of conventional JIS-SM steel plates. Eco-View steel is expected to contribute to the reduction of life cycle costs, because it can prolong the period before repainting, especially in urban areas or, specifically, in harsh corrosive environments.
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Welding Process and Consumables Aimed at Improving Fatigue Strength of Joints
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Minoru MIYATA, Reiichi SUZUKI
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The fatigue of steel structures, an important problem, is mainly attributable to stress concentration and tensile residual stress at their weld toes. In order to improve the fatigue resistance of welds, welding consumables, called low-temperature transformation (LTT) consumables, have been developed and their effectiveness demonstrated. Conventional LTT consumables, however, contain large amounts of Ni, posing problems of high cost, poor mechanical properties and low cracking resistance, which has hindered their widespread use. With this in mind, a study was conducted to replace Ni with Mn, which confirmed that Mn can more effectively improve fatigue resistance than Ni. Two newly developed consumables, "TRUSTARCTM MX-4AD" and "TRUSTARCTM LB-3AD", exploit Mn to improve the crack resistance and reduce cost. When used for additional beads, these welding consumables were confirmed to improve the fatigue resistance as well as or better than other methods such as grinding treatment, a standard method for increasing fatigue strength, or peening treatment, which is becoming widespread.
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Development and On-site Construction of GRID NETTM
-Grid-type Sabo Dam for Debris Flows of Small Boulders-
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Akihiko TAKANO, Hiroshi MORIYAMA, Takanori KAWAMURA,
Takuya SAEKI, Keita KAGOHASHI
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The deployment percentage of sabo dams is insufficient for ensuring the safety and protection of human lives against sediment disasters. Therefore, there is a great need for open-type steel sabo dams that have more than twice the sediment-trapping capacity of closed-type sabo dams. However, due to problems with their debris flow trapping capability and with their construction, open-type steel dams have not been used to counter debris flows comprising mostly of small boulders. To address this problem, we have developed GRID NETTM, a Kobe Steelmanufactured grid-type sabo dam with a mesh of rings attached to the upstream side that is capable of trapping such debris flows, and so far we have constructed four sabo GRID NET dams. This paper describes the development and construction of GRID NET.
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Development and Practical Application of a Sound Absorbing Panel Using Microperforated Aluminum for Shinkansen Tunnel Entrance Hoods
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Ph.D. Takashi HORIUCHI, Kei OGINO, Toshio YOSHIMURA,
Ichiro YAMAGIWA, Yuichi TORIGOE
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A sound absorbing panel for Shinkansen tunnel entrance hoods has been developed using a sound absorbing material featuring microperforated aluminum. The conventional microperforated aluminum material was enhanced in terms of structural strength for use in Shinkansen tunnel entrance hoods. The developed microperforated panel was designed using finite element analysis, and was subjected to strength tests, which demonstrated the high safety standards of the product. It can be applied to the ceiling of entrance hoods installed at tunnel portals of Shinkansen tracks, where it has been shown to dampen noise dramatically.
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"Eco Kyuon" -- Microperforated Sound Absorbing Panel
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Ichiro YAMAGIWA, Masaji HORIO, Shigeharu NAKAOKA,
Takahiro YAMADA
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This paper presents the development of sound absorbing panels utilizing the sound absorption mechanism of microperforated plates and foils. Microperforated plates and foils reduce acoustic energy by generating friction damping and pressure loss from the vibration of acoustically resonating aperture air. Applying this principle, we have developed a method to predictively calculate the sound absorption coefficient and applied it to develop microperforated sound absorbing panel products. A distinct advantage of this method is that these products can be designed with the optimum frequency characteristics for the desired sound absorption coefficient. These products were used to develop rail and road noise barriers that contribute to traffic noise reduction.
An additional purpose of the study was to develop a transparent sound absorbing panel solution. We selected polycarbonate, a clear polymer material, as the film material to which this technology was applied. The challenge was to overcome the drop in sound absorption due to the propensity of the transparent polymer film to intense vibrations. Improved sound absorption performance was successfully achieved by creating several combinations of manufacturable materials, calculations for predicting the sound absorption coefficient and performance verification experiments. Optimization of design elements such as sheet thickness, aperture diameter, and aperture ratio was also critical to achieving the desired performance. Since successful commercial transparent sound absorbing panels are rare, these products hold much promise for broad application in a variety of markets.
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<Feature-Ⅱ> Electronic and Electric technologies
(Advanced Materials and Apparatuses)
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Low Loss Reactor Comprising Dust Core and Copperbelt Coil
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Hiroshi HASHIMOTO, Kyoji ZAITSU, Shumpei HAYASHI, Hiroyuki MITANI,
Dr. Kenichi INOUE
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To achieve the downsizing and weight reduction of voltage boosters for hybrid and electric cars, a voltage boosting reactive coil made by winding a flat, thin copperbelt of about 0.1 to 0.3 mm in thickness was contemplated. The coil was enclosed in a pot-shaped magnetic core made of pure iron powder. Numerical analysis and a model experiment indicated the possibility of making a reactor with a coil having a high-frequency loss that has been reduced to one-third to one-tenth that of conventional reactors and has excellent heat dissipating properties. This technology has enabled the downsizing of the reactor.
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New Roll-to-Roll Sputtering System for Wide Film and Application Examples
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Toshiki SEGAWA, Yoshimitsu IKARI, Naoki OOBA,
Dr. Nobuyuki KAWAKAMI, Dr. Norihiro JIKO, Hiroaki TAO
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A new roll-to-roll sputtering system for wide film substrate is now under development; it is characterized by the connection of unit chambers in the horizontal direction. The new model is an improvement over previous models and is easily disassembled for shipping and assembled for installation; and it has kept the "open chamber concept" of previous models in the way in which the process chamber with sputtering source dynamically moves to the back of the equipment, which allows easy access to the coating zone. It also has sufficient degassing capability, thanks to a specialized degassing chamber unit. This system makes a suitable coating process for touch-panel displays or heat reflective film, etc., where the substrate film is wider. The other R2R coating system models are also introduced.
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Amorphous Oxide Semiconductor Adopting Back-channel-etch Type Thin-film Transistor
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Shinya MORITA, Mototaka OCHI, Dr. Toshihiro KUGIMIYA
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Kobe Steel has developed a new amorphous oxide semiconducting material available for the back-channeletch (BCE) type thin-film transistor (TFT) adapting mass production of flat panel displays. The material has high chemical resistivity for the conventional etchant of Mo/Al source and drain interconnection. It has been shown that good electrical characteristics and high reliability in BCE-TFT can be obtained by means of the additional annealing process to repair back-channel damage on the oxide semiconductor thin film.
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Site Flatness Measurement System with Accuracy of Sub-nanometer Order for Silicon Wafer
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Kazuhiko TAHARA, Hideki MATSUOKA, Noritaka MORIOKA,
Masato KANNAKA
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A new system using a heterodyne interferometer has been developed to measure site flatness with an accuracy of sub-nanometer order for 300 and 450 mm wafers. This system is based on a spiral scan method, which enables the measurement of global flatness and site flatness. It is also possible to measure SFQR and ESFQR with 0.5 nm (s) repeatability in an environment with as much as 5 Gal of floor vibration. This paper outlines the system and describes the experimental results for repeatability concerning global flatness and site flatness. Actual measurements turned out a GBIR of 0.68 nm (s), SFQR of 0.33 nm (s) and ESFQR of 0.39 nm (s). Next, referring to the results of the measurement of actual wafers, it explains how this new system is effective in managing the process.
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Experimental Production, Evaluation and Analysis Technologies for Li-ion Secondary Batteries
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Takayuki TSUBOTA, Takashi ACHIHA, Yoshiki HAYASHI, Dr. Rinun SYU,
Takashi IKEDA, Masato NISHIUCHI
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For Li-ion batteries used in vehicles and largescale load-leveling systems, it is necessary to clarify negative electrode or positive electrode degrades to improve durability and predict battery life. In addition, it is important to clarify the relationship between the configuration factor for internal resistance and the fabrication elements of Li-ion batteries. We therefore investigated the internal resistance determined using electrochemical impedance spectroscopy (EIS), structural changes, chemical bonding states, and the relationship between the deterioration mechanism and the internal resistance in Li-ion batteries. This study demonstrated that a separation analysis of resistance involving the disassembly and re-assembly of a battery is effective for identifying the specific source of degradation. Thus, it is possible to clarify the main factors contributing to the characteristic fading of a battery via internal resistance and degradation analysis.
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Nb3Sn Wire Technology for High-field Superconducting Magnet
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Kazuyoshi SAITO, Kyoji ZAITSU
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Nb3Sn superconducting wires are widely used for highfield superconducting magnets, and the NMR magnet is one of the most successful applications. In order to realize a large Jc (critical current density), which is essential to high-field superconducting magnets, several different types of production methods have been developed, such as the bronze-route method, the powderin-tube method and the internal tin method. This article first reviews those wire production methods and the technique for Jc value enhancement. After that, current developments in the large Jc Nb3Sn superconducting wire of Kobe Steel and Japan Superconductor Technology are described. The magnetic field dependence of Jc values in each manufacturing method is presented and the strong and weak points for the industrial usage of each manufacturing method are also described. An effective guideline for achieving the best superconducting magnet performance is discussed, optimizing the placement of Nb3Sn wire manufactured by each method. The proposed design concept uses PIT method wire for winding the innermost layer and IT method wire for winding the outer layer. This idea could realize an NMR magnet with a high magnetic field and superior cost performance.
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