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Acta Mechanica Sinica 2009年第2期25卷 149-160页

作者： M.Saka T.Hasegawa Department of Nanomechanics Tohoku University

Temperature is one of the physical quantifies through which quantitative evaluation of the safety and reliability of industrial products can be achieved, and this has been used widely in practice. Under any environmental condifion, regardless of the size of the object to be inspected, accurate and reliable measurement of temperature is of great practical importance. This review article presents a simple and direct method of temperature measurement, that can be applied to the local areas with difficulty in measuring the temperature by using normal thermometers. In the present article, two different application examples are demonstrated. One addresses the study of the electromigration of solders which are used as bonding metals in electronic devices （micro-structures）. The application of the method to the shaft of a motor used in heavy industrial fields is explained as the second.

关键词： Temperature measurement Chemicalreagents Melting point Temperature distribution

Self-calibration and Compensation of Setting Errors for Surface Profile Measurement of a Microstructured Roll Workpiece

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Chinese Journal of Mechanical Engineering 2014年第1期27卷 14-22页

作者： GAO Wei XU Bin TAKEISHI Toshiki SHIMIZU Yuki ITO So Department of Nanomechanics Tohoku University School of Manufacturing Science and Engineering Sichuan University

Microstructured roll workpieces have been widely used as functional components in the precision industries. Current researches on quality control have focused on surface profile measurement of microstructured roll workpieces, and types of measurement systems and measurement methods have been developed. However, low measurement efficiency and low measurement accuracy caused by setting errors are the common disadvantages for surface profile measurement of microstructured roll workpieces. In order to shorten the measurement time and enhance the measurement accuracy, a method for self-calibration and compensation of setting errors is proposed for surface profile measurement of microstructured roll workpieces. A measurement system is constructed for the measurement, in which a precision spindle is employed to rotate the roll workpiece and an air-bearing displacement sensor with a micro-stylus probe is employed to scan the microstructured surface of the roll workpiece. The resolution of the displacement sensor is 0.14 nm and that of the rotary encoder of the spindle was 0.15r~. Geometrical and mathematical models are established for analyzing the influences of the setting errors of the roll workpiece and the displacement sensor with respect to the axis of the spindle, including the eccentric error of the roll workpiece, the offset error of the sensor axis and the zero point error of the sensor output. Measurement experiments are carded out on a roll workpiece on which periodic microstructures are a period of 133 i^m along the circumferential direction. Experimental results demonstrate the feasibility of the self-compensation method. The proposed method can be used to detect and compensate the setting errors without using any additional accurate artifact.

关键词： measurement profile setting error self-calibration compensation microstructure roll workpiece

Effect of Residual Stress on the Corrosion Behavior of Austenitic Stainless Steel

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Advances in Chemical Engineering and Science 2015年第1期5卷 62-71页

作者： Osamu Takakuwa Hitoshi Soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan

In this paper we demonstrate that the residual stress introduced by several different surface finishes affects the critical current density for passivation and the passive current density in the anodic polarization curve of austenitic stainless steel and that those critical current densities can be reduced by controlling the residual stress by applying a cavitating jet to the backs of specimens. The results show that the current density either increased or decreased depending on the surface finish, and that was decreased by introducing compressive residual stress for all surface finishes.

关键词： Residual Stress Corrosion Passive Film Plarization Stainless Seel

Single and multiple optical switches that use freestanding silicon nanowire waveguide couplers

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Light(Science & Applications) 2012年第1期1卷 92-99页

作者： Yuta Akihama Kazuhiro Hane Department of Nanomechanics Tohoku UniversitySendai 980-0952Japan

Silicon photonic devices consisting of nanowire waveguides are a promising technology for on-chip integration in future optical telecommunication and interconnection systems based on silicon-large scale integration fabrication.However,the accommodation of variable optical components on a chip remains challenging due to the small size of microchips.In this study,we investigated the characteristics of a microelectromechanical silicon nanowire waveguide switch with a gap-variable coupler.Due to its capacitive operation,the proposed waveguide switch consumed negligible power relative to switches that use a thermo-optical effect and carrier injection.The proposed switch was characterized using analyses based on coupled-mode theory for rectangular waveguides,as well as a simulation using the finite difference time domain method.A 2×2 single switch with an improved configuration and a 2×6 multiple switch composed of the 2×2 switches was designed and fabricated by a combination of electron beam lithography,fast-atom beam etching and hydrofluoric acid vapor sacrificial etching.The properties of the switches were measured and evaluated at a wavelength of 1.55 μm.

关键词： microelectromechanical systems optical switch silicon photonics

Towards Raman imaging of centimeter scale tissue areas for real-time opto-molecular visualization of tissue boundaries for clinical applications

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Light(Science & Applications) 2022年第6期11卷 1029-1031页

作者： Oleksii Ilchenko Yurii Pilhun Andrii Kutsyk Technical University of Denmark Department of Health TechnologyCenter for Intelligent Drug Delivery and Sensing Using Microcontainers and NanomechanicsKgsLyngby 2800Denmark Lightnovo ApS Birker?d 3460Denmark Taras Shevchenko National University of Kyiv Department of Quantum Radio PhysicsKyivUkraine Technical University of Denmark Department of Energy Conversion and StorageKgsLyngby 2800Denmark

Raman spectroscopy combined with augmented reality and mixed reality to reconstruct molecular information of tissue surface.

关键词： surface clinical reality

Movement of Dislocations in the Sub-Surface of a Polycrystalline Metal by Cavitation Peening Observed by Transmission Electron Microscopy

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Materials Sciences and Applications 2015年第2期6卷 140-144页

作者： Osamu Takakuwa Akihiko Chiba Hitoshi Soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan Institute for Materials Research Tohoku University Sendai Japan

The impact produced when cavitation bubbles collapse can be utilized to modify surfaces in the same way as shot peening and it is called cavitation peening (CP). CP is one of a number of surface modification techniques used to improve the fatigue strength of metallic materials by introducing compressive residual stress. Although it has been shown by an X-ray diffraction method that CP decreases the micro-strain related to dislocations in the sub-surface of a polycrystalline material, the mechanism for this decrease is unclear. In this paper, the movement of dislocations by CP was observed using transmission electron microscopy (TEM).

关键词： Microstructure Transmission Electron Microscopy Dislocation Surface Modification Cavitation

The Use of Cavitation Peening to Increase the Fatigue Strength of Duralumin Plates Containing Fastener Holes

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Materials Sciences and Applications 2014年第6期5卷 430-440页

作者： Hitoshi Soyama Department of Nanomechanics Tohoku University Sendai Japan

An effective method for improving the fatigue life of Duralumin plates with fastener holes, such as those used in the construction of aircraft, is to introduce a compressive residual stress around the fastener holes. Cavitation peening is a novel peening method that uses the cavitation impact produced when a high-speed water jet is injected into a water-filled chamber. In this paper, Duralumin plate specimens with holes were treated by cavitation peening under various conditions, and the fatigue strength of the specimens was determined using a plate bending fatigue test. It was revealed that a compressive residual stress was introduced not only on surfaces perpendicular to the axis of the cavitating jet but also on the walls of holes which were parallel to this. It was found that a 51% improvement in fatigue strength could be achieved by cavitation peening. Note that this is first report demonstrating an improvement in the fatigue life of Duralumin plates with fastener holes by cavitation peening.

关键词： Fatigue Fastener Hole Duralumin Cavitation Peening Residual Stress

Flexible micro-LED display and its application in Gbps multi-channel visible light communication

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npj Flexible Electronics 2022年第1期6卷 973-979页

作者： Luhing Hu Jaeyong Choi Sumin Hwangbo Do-Hoon Kwon Bongkyun Jang Seunghyeon Ji Jae-Hyun Kim Sang-Kook Han Jong-Hyun Ahn School of Electrical and Electronic Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Nanomechanics Nano-Convergence Mechanical Systems Research DivisionKorea Institute of Machinery&Materials(KIMM)156 Gajeongbuk-roYuseong-guDaejeon 34103Republic of Korea

A flexible full-color micro-LED display with high mechanical robustness was fabricated by printing quantum dots(QDs)on a blue micro-LED array using standard photolithography.The red and green colors yielded from QDs exhibit a better color gamut than conventional color filters.The light conversion efficiency was enhanced by adding TiO2 nanoparticles to the QD-photoresist composite.This full-color micro-LED display was successfully mounted on various unusual substrates such as curved glass,fabrics,and human skin,enabling diverse optoelectronic applications.In addition,wireless multi-channel visible light communication(VLC)based on the wavelength-division-multiplexing orthogonal-frequency-division-multiplexing(WDM-OFDM)technique was demonstrated using a QD-based color micro-LED panel.A high data transmission rate of 1.9 Gbps was successfully obtained owing to the high electrical-optical modulation bandwidth of the QD-based micro-LED panel.

关键词： communication Gbps visible

Estimation of the Yield Stress of Stainless Steel from the Vickers Hardness Taking Account of the Residual Stress

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Journal of Surface Engineered Materials and Advanced Technology 2013年第4期3卷 262-268页

作者： Osamu Takakuwa Yusuke Kawaragi Hitoshi Soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan.

In this paper, a method that uses the Vickers hardness to estimate the yield stress of a metallic material with taking account of residual stress is proposed. Although the yield stress of bulk metal can be evaluated by a tensile test, it cannot be applied to local yield stress varied by surface modification methods, such as the peening technique which introduces high compressive residual stress at the surface. Therefore, to evaluate the local yield stress employing a relatively easy way, the Vickers hardness test was conducted in this paper. Since the Vickers hardness depends on both the residual stress and the yield stress, the relationship between the residual stress and the Vickers hardness was experimentally examined. It was concluded that the yield stress of the surface treated by several peening techniques can be estimated from the Vickers hardness once this has been corrected for residual stress.

关键词： Peening Yield Stress Hardness Residual Stress

Optimizing the Conditions for Residual Stress Measurement Using a Two-Dimensional XRD Method with Specimen Oscillation

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Advances in Materials Physics and Chemistry 2013年第1期3卷 8-18页

作者： Osamu Takakuwa Hitoshi Soyama Department of Nanomechanics Graduate School of Engineering Tohoku University Sendai Japan

In order to optimize the conditions for residual stress measurement using a two-dimensional X-ray diffraction (2D-XRD) in terms of both efficiency and accuracy. The measurements have been conducted on three stainless steel specimens in this study. The three specimens were processed by annealing, a cavitating jet in air and a disc grinder, with each method introducing different residual stresses at the surface. The specimens were oscillated in the ω-direction, representing a right-hand rotation of the specimen about the incident X-ray beam. The range of the oscillation, Δω, was varied and optimum Δω was determined. Moreover, combinations of the tilt angle between the specimen surface normal and the diffraction vector, ψ, with the rotation angle about its surface normal, f, have been studied with a view to find the most optimum condition. The results show that the use of ω oscillations is an effective method for improving analysis accuracy, especially for large grain metals. The standard error rapidly decreased with increasing range of the ω oscillation, especially for the annealed specimen which generated strong diffraction spots due to its large grain size.

关键词： Two-Dimensional XRD Diffraction Ring Oscillation Residual Stress Stainless Steel