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Round Robin Study on the Thermal Conductivity/Diffusivity of a Gold Wire with a Diameter of 30μm Tested via Five Measurement Methods

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Journal of Thermal Science 2022年第4期31卷 1037-1051页

作者： ABE Ryo SEKIMOTO Yuki SAINI Shirkant MIYAZAKI Koji LI Qin-Yi LI Dawei TAKAHASHI Koji YAGI Takashi NAKAMURA Masakazu division of materials science nara institute of science and technologyikoma 630-0192japan department of mechanical and control engineering kyushu institute of technologykitakyushu 804-8550japan department ofaeronautics and astronautics kyushu universityfukuoka819-0395japan international institute for carbon-neutral energy research(wpi-i2cner) kyushu universityfukuoka 819-0395japan national metrology institute of japan national institute of advanced industrial science and technology tsukuba 305-8565japan

Since first establishing thermal measurement techniques for micrometer-scale wires,various methods have been devised and improved upon.However,the uncertainty of different measurements on the same sample has not yet been discussed.In this work,a round robin test was performed to compare the thermal conductivity and thermal diffusivity measurement methods for a fine metal wire.The tested material was a pure gold wire,with a diameter of 30μm.The wire was cut into certain lengths and distributed to four institutions using five different measurement methods:the direct current(DC)self-heating method,the DC heating T-type method,the 3ωmethod for thermal conductivity,the scanning laser heating alternating current(AC)method,and the spot periodic heating radiation thermometry method for thermal diffusivity.After completing the measurements,the reported thermal conductivity and thermal diffusivity at room temperature,i.e.,317 W·m^(-1)·K^(-1)and 128×10^(-6)m^(2)·s^(-1),respectively,were adopted as references for comparison with the measurement results.The advantages and disadvantages of each method are described in terms of the effect of electrical and thermal junctions fabricated on a wire,such as an electrode,a thermocouple,and a heat bath.The knowledge obtained from the tested methods will be useful for selecting and designing a measurement technique for various wire-like materials.

关键词： thermal conductivity thermal diffusivity round robin test microscale wire

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Optimization of body configuration and joint-driven attitude stabilization for transformable spacecraft under solar radiation pressure

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Astrodynamics 2024年第1期8卷 47-60页

作者： yuki Kubo Toshihiro Chujo Institute of Space and Astronautical Science Japan Aerospace Exploration AgencyKanagawa252-5210Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan

The solar sail is one of the most promising space exploration systems due to its theoretically infinite specific impulse achieved through solar radiation pressure(SRP).Recently,researchers have proposed“transformable spacecraft”capable of actively reconfiguring their body configurations using actuatable joints.Transformable spacecraft,if used similarly to solar sails,are expected to significantly enhance orbit and attitude control capabilities owing to their high redundancy in control degrees of freedom.However,controlling them becomes challenging due to their large number of inputs,leading previous researchers to impose strong constraints to limit their potential control capabilities.This study focuses on novel attitude control techniques for transformable spacecraft under SRP.We developed two methods,namely,joint angle optimization to obtain arbitrary SRP force and torque,and momentum damping control driven by joint angle actuation.Our proposed methods are formulated in a general manner and can be applied to any transformable spacecraft comprising front faces that can predominantly receive the SRP on each body.The validity of our proposed method is confirmed through numerical simulations.Our study contributes to making most of the high control redundancy of transformable spacecraft without the need for expendable propellants,thus significantly enhancing the orbit and attitude control capabilities.

关键词： solar sail transformable spacecraft attitude-joint coupled motion attitudestabilization

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Feasible Resolution of Angular Displacement Measurement by an Optical Angle Sensor Based on Laser Autocollimation

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Nanomanufacturing and Metrology 2023年第4期6卷 46-59页

作者： Hyunsung Lim yuki Shimizu Division of Mechanical and Aerospace Engineering Hokkaido UniversitySapporoJapan

The feasible resolution of angular displacement measurement by an optical angle sensor based on laser autocollimation is investigated.Improving the sensor sensitivity while maintaining the noise level of the sensor signal as low as possible is necessary to achieve high-resolution angular displacement measurement.In this paper,the contribution of each component,such as a photodiode,a trans-impedance amplifer,and an analog-to-digital converter in the optical angle sensor,to the noise level of the sensor signal is frst estimated on the basis of theoretical equations.The feasible sensitivity of the optical angle sensor is also estimated in numerical calculations.The sensitivity of a photodiode element at the edge of its photosensitive area is evaluated in experiments to realize the estimation of the angle sensor sensitivity.Experimental results are applied to the numerical calculations.The infuences of the measurement laser beam diameter,the spot diameter of the focused laser beam on the photosensitive area,and the focal length of the collimator objective of the optical angle sensor are also consid-ered in the numerical calculations.Finally,a prototype optical setup is developed.Experiments are performed to demonstrate that a compact optical angle sensor based on laser autocollimation with a collimator objective having a focal length shorter than 100 mm can achieve a resolution beyond 0.001 arc-second with a bandwidth of 1 kHz.This resolution is better than those achieved by commercial autocollimators employing an image sensor or a position-sensitive detector.The industrial contribution of this paper lies in the detailed breakdown of noise components in the readout signal of an angle sensor in a practical condition and the systematic estimation of its feasible resolution as well as its sensitivity.

关键词： Angle measurement Resolution Laser autocollimation Photodiode Signal noise

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Current and future trends in whole genome sequencing in cancer

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Cancer Biology & Medicine 2024年第1期21卷 16-20页

作者： yuki Katsuya Department of Experimental Therapeutics National Cancer Center Hospital5-1-1 TsukijiChuo-kuTokyo 104-0045Japan

Cancer remains a formidable global health challenge affecting millions of lives annually.For decades,conventional cancer treatments used a one-size-fits-all approach,overlooking the intricate genetic variations that drive tumors.The emergence of cancer genomics has ushered in a new era of personalized and targeted cancer therapies.The Human Genome Project,which was launched in 1990 and completed in 2003。

关键词： cancer Cancer annually

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The Distribution of the Oceanic Sea Skaters, <i>Halobates</i>inside and outside the <i>Kuroshio</i>

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Open Journal of Marine Science 2017年第3期7卷 433-444页

作者： Tetsuo Harada yuki Osumi Takero sekimoto Koki Iyota Takashi Shiraki Shiho Takenaka Hitomi Takeuchi Mitsuru Nakajo Toshiki Tamura Laboratory of Environmental Physiology Graduate School of Integrated Arts and Sciences of Human and Nature Kochi University Kochi Japan Laboratory of Science Education Graduate School of Integrated Arts and Sciences of Human and Nature Kochi University Kochi Japan

The purpose of this study was to clarify the distribution of oceanic Halobates in the area of the Kuroshio flowing near the southern shore in the direction of 100° - 120°, and also to compare the population density of Halobates between the area within or outside the area of the Kuroshio and also among seasons. This study was carried out during 8 cruises by R/V TANSEIMARU. The Kuroshio area south of the southern Japan coast (30°00'N - 35°00'N, 130°25'E - 141°04'E) was dominated by H. sericeus, and the averaged population-density of this species was significantly higher inside the Kuroshio than outside this current. On the Kuroshio, H. sericeus was dominant with the population density of 16,396.4 km-2 ± 66,138.4 [26] (Mean ± SD [n]), whereas the density of H. germanus was 8,581.9 km-2 ± 24,443.2 [26]. The two oceanic sea skaters, H. sericeusand H. germanus showed significant seasonal variation in the population density, with significantly higher density in October than other months, whereas there was no such significant October peak in the cosmopolitan oceanic sea skater, H. micans. The results of this study may suggest that H. sericeus could use the Kuroshio as a transportation tool to distribute a wide latitude area of from 10°N to 40°N in the western tropical, subtropical and temperate area in the Pacific Ocean.

关键词： Halobates Oceanic Sea Skaters Population Density Season The Kuroshio

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Laser-assisted direct roller imprinting of large-area microstructured optical surfaces

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Microsystems & Nanoengineering 2024年第1期10卷 257-266页

作者： Keisuke Nagato Ken Takahashi yuki Yajima Masayuki Nakao Department of Mechanical Engineering Graduate School of EngineeringThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan

In this study,a high-throughput fabrication method called laser-assisted direct roller imprinting(LADRI)was developed to lower the cost of nanoimprinting large-area polymer films and to address problems associated with nanoimprinting,namely,microstructural damage and precision in flatness of entire film.With LADRI,the laser directly heats the microstructured surface of the roller mold,which heats and melts the surface of a polymethyl methacrylate(PMMA)film to replicate the microstructures on the mold rapidly.In this study,the effects of laser power density,scanning speed,size of the microstructures,and contact pressure on the replication speed were investigated experimentally.The replication speed increased as the power and scanning speed increased.However,because the film required heating until it filled the entire depth of the microstructure,an appropriate replication speed was necessary.This result was supported by simulation of the temperature distribution inside the mold and the PMMA using transient heat conduction analyses.To demonstrate the applications of LADRI,two different optical surfaces were replicated:an antireflection(AR)structure with conical structures sized several hundred nanometers and a lightextraction structure with a microlens array(MLA)comprising 10μm lenses,for display and illumination,respectively.The replication degree of the MLA was governed by the contact pressure.Polymer flow simulation indicated that the heat conduction and flow speeds of the melted PMMA surface were comparable within several tens of micrometers.In addition,the reflectivity of the AR structure decreased from 4 to 0.5%,and the light intensity of the light-extraction structure increased by a factor of 1.47.

关键词： microstructure roller conduction

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Hemodynamic Profiling Using a Cardiac Index–Systemic Vascular Resistance Plot in Patients with Fontan Circulation

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Congenital Heart Disease 2023年第4期18卷 431-445页

作者： yuki Kawasaki Takeshi Sasaki Daisuke Kobayashi Division of Pediatric Cardiology Osaka City General Hospital Pediatric Medical CenterOsaka5340021Japan Division of Cardiology St.Louis Children’s HospitalDepartment of PediatricsWashington University in St.LouisSt.LouisMO 63130USA

Background: Elevated Fontan pressure (FP) alone cannot fully predict clinical outcomes. We hypothesized thathemodynamic profiling using a cardiac index (CI)-systemic vascular resistance (SVR) plot could characterize clinicalfeatures and predict the prognosis of post-Fontan patients. Methods: We included post-Fontan patients whounderwent cardiac catheterization at age < 10 years. Patients were classified into four categories: A, CI ≥ 3, SVRindex (SVRI) ≥ 20;B, CI < 3, SVRI ≥ 20;C, CI ≥ 3, SVRI < 20;and D, CI < 3, SVRI < 20. The primary outcome wasfreedom from the combined endpoint: new onset of protein-losing enteropathy or plastic bronchitis, heart transplant,and death. Clinical and hemodynamic variables and freedom from the endpoint were compared betweenthe hemodynamic categories and outcome predictors were evaluated. Results: Eighty-three patients wereincluded. Median follow-up was 5.3 years. Category A/B/C/D consisted of 4/15/53/11 patients, respectively. Allthe patients in category A were New York Heart Association I/II and had a significantly lower pulmonary vascularresistance index (PVRI). Patients in category C had lower pulmonary/systemic blood flow. Patients in category Dhad a higher PVRI and had the poorest freedom from the endpoint (44% at 5 years). Elevated FP and category Dwere outcome predictors. Conclusions: CI-SVR plots was a novel adjunctive method for Fontan hemodynamicprofiling.

关键词： Cardiac index systemic vascular resistance perfusion pressure hemodynamic category fontan circulation prognosis

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Description of sand–metal friction behavior based on subloadingfriction model

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Friction 2022年第10期10卷 1660-1675页

作者： Toshiyuki OZAKI yuki YAMAKAWA Masami UENO Koichi HASHIGUCHI Kyushu Electric Engineering Consultants Inc. Fukuoka 810-0005Japan Department of Civil and Environmental Engineering Tohoku UniversitySendai 980-8579Japan University of the Ryukyus Okinawa 903-0213Japan MSC Software Ltd. Tokyo 101-0054Japan Kyushu University Fukuoka 819-0395Japan

A subloading-friction model is formulated to describe the smooth transient variation from static friction to kinetic friction,the recovery to static friction after the sliding velocity decreases,and the accumulation of sliding displacement under the cyclic loading of contact stress.In the past relevant studies,however,the model formulation used for simulations is limited to the hypoelastic-based plasticity framework,and the validation of the model is limited to simulations of the test data for metal-to-metal friction.In this study,the formulation of the subloading-friction model based on a hyperelastic-based plasticity framework is adopted.In the fields of civil,geotechnical,agricultural engineering,and terramechanics,the interaction between soils and metals is critical,as reflected in construction and agricultural machinery,foundation piles,and retaining walls.The validity of the model for describing the friction between various sands and metals is verified by simulations of the experimental data under monotonic and cyclic loadings.

关键词： subloading-friction model sand-metal friction monotonic/cyclic sliding static/kinetic friction

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弘扬体育精神助力少儿体能发展——卡乐咪体能馆2—8岁儿童运动体能

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风采童装 2022年第6期 45-51+44页

作者： yuki

据相关调查，当下青少年身体素质大幅度下滑，其中较严重的问题是肥胖、近视、脊柱侧弯。身体健康问题进一步导致心理问题，而运动成为了解决这些问题的一剂良药。少年强则国家强，孩子是国家的未来和民族的希望，孩子的身体素质是未来...

据相关调查，当下青少年身体素质大幅度下滑，其中较严重的问题是肥胖、近视、脊柱侧弯。身体健康问题进一步导致心理问题，而运动成为了解决这些问题的一剂良药。少年强则国家强，孩子是国家的未来和民族的希望，孩子的身体素质是未来发展的基础。国务院、教育部、国家体育总局颁布了一系列加强青少年儿童体育锻炼的相关文件，教育部在中小学生的考试和日常学习中也增加了体育的比重。

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Psychosis symptoms following aberrant immunity in the brain

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Neural Regeneration Research 2021年第3期16卷 512-513页

作者： Akitoshi Ozaki yuki Yamawaki Gen Ohtsuki Department of Biophysics Kyoto University Graduate School of ScienceKyotoJapan The Hakubi Center for Advanced Research Kyoto UniversityKyotoJapan Department of Drug Discovery Medicine Kyoto University Graduate School of MedicineKyotoJapan

Neuroinflammation in the brain is thought related to the emergence of various psychoses,although the identifying regional significance,the involvement of immune-cells and lymphocytic activity,and ways for the therapeutic recovery are under the effort of researchers.We recently revealed that the cerebellar acute inflammation causes the symptoms manifested in mood disorders or developmental disorders,which were associated with hyperexcitability due to immune-triggered plasticity and the overconnectivity between the inflamed cerebellum and prefrontal cortex(Yamamoto et al.,2019).

关键词： inflammation immunity involvement

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