Yamagata Research Institute of Technology

Yamagata-shi, Japan

Yamagata Research Institute of Technology

Yamagata-shi, Japan
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Saito H.,Yamagata Research Institute of Technology | Jung H.,Nagoya University | Shamoto E.,Nagoya University | Wu T.-C.,Metal Industries Research and Development Center | And 2 more authors.
Precision Engineering | Year: 2017

Elliptical vibration cutting with single-crystalline diamond tools is applied to mirror surface machining of high-alloy steels such as cold work die steels and high-speed tool steels with a hardness of more than 60 HRC. Although practical mirror surface machining of hardened die steels such as Stavax (modified AISI 420) with a hardness of 53 HRC has been realized with the elliptical vibration cutting, lives of single-crystalline diamond tools are not sufficiently long in machining of some high-alloy steels, that may be caused by a large amount of alloy elements. In order to clarify the influence of the alloy elements on the diamond tool damage, the elliptical vibration cutting experiments are conducted on six kinds of high-alloy steels and four kinds of pure metals which are the same as the alloy elements. Mechanical properties of the alloy steels, i.e. difference in hardness between carbides and matrices, and the number of small carbides, are measured, and their influence on the micro-chippings are investigated. The chemical states of the alloy elements in high-alloy steels are analyzed using an X-ray diffraction (XRD) and an electron probe micro analyzer (EPMA), and their influence on the tool wear is discussed. Based on the investigation, a mirror surface machining of DC53, which has a high hardness of 62.2 HRC and the best machinability in the tested high-alloy steels, is demonstrated, and a mirror surface with a roughness of Rt 0.05. μm is obtained successfully. © 2017 Elsevier Inc.

Suga M.,Clair Project JEOL Ltd. | Nishiyama H.,Clair Project JEOL Ltd. | Konyuba Y.,Clair Project JEOL Ltd. | Iwamatsu S.,Yamagata Research Institute of Technology | And 4 more authors.
Ultramicroscopy | Year: 2011

Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100. nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields. © 2011 Elsevier B.V.

Suzuki T.,Yamagata Research Institute of Technology | Kato M.,Yamagata Research Institute of Technology
ECS Transactions | Year: 2012

Ni-based carbon nanotube (CNT) composite coatings have low friction and wear resistance properties improved by codepositing CNTs in the matrix. However, there are some large nodules on the surface of the Ni-CNT composite coatings because of codepositing large CNT aggregates in Ni matrix. The purpose of this study was to improve the surface roughness of the Ni-CNT composite coatings. For the purpose, two kinds of ultrasonic assisted electroplating using bath sonication method or horn sonication method were proposed. As a result, horn sonication method could effectively decrease the nodule on the coating and improve the surface roughness. The surface roughness of 0.1 μm Ra was obtained. Carbon component of the coating formed with bath sonication was 15at%. The component of the coatings formed with horn sonication was 45at%. Horn sonication increased CNTs concentration in the coatings three times compared with bath sonication. © The Electrochemical Society.

Suzuki T.,Yamagata Research Institute of Technology | Kobayashi S.,Yamagata Research Institute of Technology
Electrochimica Acta | Year: 2013

Mechanisms of the Titanium carbide (TiC) layer formation in electrical discharge coating (EDC) using TiC powder electrodes were investigated. We have observed and analyzed the migration and adhesion of TiC powder in single pulse discharges in electrical discharge machining (EDM) as the first step towards elucidating the adhesion mechanism of TiC with the use of TiC powder and high speed steel as the electrodes and workpiece, respectively. The adhesion mechanism of TiC powder was discussed from the shape and composition distribution of the discharge crater and the voltage and current waveforms at the time of discharge. TiC is directly supplied from the electrode to the surface of the workpiece by single pulse discharge without the presence of TiC between the electrodes. When the voltage remains constant during discharge, the melted and resolidified TiC is localized in the crater. When a temporary voltage drop occurs during discharge, the clustered TiC that has maintained its powder form is present in the crater. The temporary voltage drop during discharge occurred by existing the large clustered TiC powder between the electrodes and by the bulge of the crater. The amount of TiC provided from TiC electrodes to TiC layer is smaller than that to high speed steel. The thickness of TiC layer on high speed steel increases and converges some constant value with increasing EDC process time because of the balance of TiC removal and adhesion by a single pulse discharge. © 2013 Elsevier Ltd.

Tobitsuka K.,Yamagata Research Institute of Technology
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2013

La France pear is one of the most popular European pears in Japan. Its typical charms include the fine aroma and the smooth texture. In Japan, Yamagata prefecture is one of the major La France pear-producing areas. To promote new local specialty processed foods and drinks in the Yamagata district, we developed two new food materials made from La France pear. One is a powdered material, "La France powder", and the other is a liquid material, "La France essence". Their beneficial characteristics include their natural and fine aroma. They are currently being utilized in the development of many new processed foods, drinks, etc. In this context, an overview of their development and examples of their applications are presented.

Tamura T.,Japan National Institute of Advanced Industrial Science and Technology | Matsuki T.,Yamagata Research Institute of Technology | Miwa K.,Japan National Institute of Advanced Industrial Science and Technology
Materials Transactions | Year: 2011

It is known that mechanical vibrations which applied during solidification affect microstructure refinement. However, it is not completely understood which factor of vibrations is important for microstructure refinement. Factors of vibrations are frequency, acceleration, velocity and amplitude. In this study, the effect of mechanical vibrations on microstructure refinement of Al-7 mass % Si alloys was investigated systematically. The mechanical vibrations were applied to the melt in an alumina crucible from about 923 K to 863 K, and the crucible was quenched in water at 863 K. As a result, it was found that the velocity of mechanical vibrations corresponding to the vibration energy is important factor for primary crystals refinement. The mechanical vibrations with high velocity regardless of frequency can refine the primary crystals. It is considered that the mechanical vibrations promote heterogeneous nucleation just below the liquidus temperature. © 2011 The Japan Institute of Light Metals.

Saito H.,Yamagata Research Institute of Technology | Jung H.,Nagoya University | Shamoto E.,Nagoya University
Precision Engineering | Year: 2016

Elliptical vibration cutting of hardened die steel with coated carbide tools is examined in this research in order to achieve low-cost high-precision machining. Diamond coated tools are applied because of superior hardness of their polycrystalline diamond coating and its low manufacturing cost. TiN coated tools are also tested, since they are widely used for conventional machining of steels. Machinability of hardened die steel by the elliptical vibration cutting with coated carbide tools is discussed in three aspects in this study, i.e. transferability of cutting edge profile to cut surface, cutting force, and tool life. The transferability is evaluated quantitatively by calculating correlation coefficients of measured roughness profiles. It is clarified that the diamond coated tools have high transferability which leads to diffraction of light on the surface machined at micro-scale pick feed. Total cutting forces including ploughing components are measured at various feed rates, and then shearing components and ploughing components are separated utilizing linear regression. The measured results indicate, for example, that the all forces become considerably smaller only when elliptical vibration is applied to the TiN coated tool without cutting fluid. It is also found that this considerable reduction of forces interestingly corresponds to higher friction coefficient, which is identified from the ploughing components. Tool life tests are carried out by various machining methods, i.e. elliptical vibration/ordinary wet/dry cutting with diamond/TiN coated tools. The result shows, for example, that the flank wear is smallest in the wet elliptical vibration cutting with the diamond coated tool. © 2016 Elsevier Inc.

Hirata M.,Yamagata Research Institute of Technology | Hirata M.,Yamagata University | Ochiai B.,Yamagata University | Endo T.,Kinki University
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2010

Star-shaped poly(phenoxy propylene sulfide) [poly (PPS)] were synthesized by anionic polymerization using a trifunctional initiator (I1) derived from a trifunctional five-membered cyclic dithiocarbonate and benzyl amine. Conditions for the anionic polymerization of PPS were optimized to obtain polymers with desired Mns and narrow MW/Mns. The best catalyst and solvent were DBU and DMF, respectively. The star-shaped structure of the resulting star poly(PPS) was supported by SEC analysis. The refractive indexes (nD) of the star poly (PPS) were relatively high (>1.64). © 2009 Wiley Periodicals, Inc.

Suzuki T.,Yamagata Research Institute of Technology | Konno T.,Just Co.
Precision Engineering | Year: 2014

Ni-based CNT composite (Ni-CNT) coatings were applied for improving the grain bonding strength of electroplated diamond tools. Further, since it is extremely important for the coatings to have good surface roughness for applications to micro-electroplated diamond tools, ultrasonic-vibration stirring was employed for improving the surface roughness of the coatings. The effects of the amount of CNTs in the plating bath on the hardness and grain bonding strength of Ni-CNT coatings were evaluated. Finally, we evaluated the tool life of microelectroplated diamond tools comprising Ni-CNT coatings as the topcoat layers by conducting experiments involving side machining and hole-drilling. The Vickers hardness of Ni-CNT coatings electroplated in a bath that contained more than 1-g/l CNTs exceeded 500 HV. The grain bonding strength can be improved by codepositing CNTs in Ni coatings and was almost 1.3 times in our estimations. In the case of the side machining of glass plates, electroplated diamond tools composed of the Ni-CNT coatings had a tool life approximately eight times longer than that of normal tools. Moreover, micro electroplated diamond tools also had a longer tool life for drilling holes in fused quartz glass. This represents the first experimental verification of the efficacy of Ni-CNT coatings in improving the grain bonding strength. In this manner, we have demonstrated that Ni-CNT coatings are extremely effective for improving the grain bonding strength of electroplated diamond tools. © 2014 Elsevier Inc.

Sugimoto M.,Keio University | Kosekl T.,Yamagata Research Institute of Technology | Hirayama A.,Keio University | Abe S.,Keio University | And 3 more authors.
Journal of Agricultural and Food Chemistry | Year: 2010

The aim of this study was to explore the association between taste and metabolite profiles of Japanese refined sake. Nontarget metabolome analysis was conducted using capillary electrophoresis mass spectrometry. Zatsumi, an unpleasant not clear flavor, and sweetness, bitterness, and sourness were graded by four experienced panelists. Regression models based on support vector regression (SVR) were used to estimate the relationships among sensory evaluation scores and quantified metabolites and visualized as a nonlinear relationship between sensory scores and metabolite components. The SVR model was highly accurate and versatile: the correlation coefficients for whole training data, cross-validation, and separated validation data were 0.86, 0.73, and 0.73, respectively, for zatsumi. Other sensory scores were also analyzed and modeled by SVR. The methodology demonstrated here carries great potential for predicting the relevant parameters and quantitative relationships between charged metabolites and sensory evaluation in Japanese refined sake. © 2009 American Chemical Society.

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