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Computer Modeling in Engineering & Sciences 2024年第2期138卷 1237-1258页

作者： daisuke Ishihara Naoto Takayama Department of Intelligent and Control Systems Kyushu Institute of TechnologyIizuka820-8502Japan

In this study, we propose an algorithm selection method based on coupling strength for the partitioned analysis ofstructure-piezoelectric-circuit coupling, which includes two types of coupling or inverse and direct piezoelectriccoupling and direct piezoelectric and circuit coupling. In the proposed method, implicit and explicit formulationsare used for strong and weak coupling, respectively. Three feasible partitioned algorithms are generated, namely(1) a strongly coupled algorithm that uses a fully implicit formulation for both types of coupling, (2) a weaklycoupled algorithm that uses a fully explicit formulation for both types of coupling, and (3) a partially stronglycoupled and partially weakly coupled algorithm that uses an implicit formulation and an explicit formulation forthe two types of coupling, *** examples using a piezoelectric energy harvester,which is a typicalstructure-piezoelectric-circuit coupling problem, demonstrate that the proposed method selects the most costeffectivealgorithm.

关键词： Multiphysics coupling strength partitioned algorithm structure-piezoelectric-circuit coupling strongly coupled algorithm weakly coupled algorithm

Unsteady Behavior of Surge and Rotating Stall in an Axial Flow Compressor

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Journal of Thermal Science 2012年第4期21卷 302-310页

作者： Yutaka OHTA Yutaka FUJITA daisuke MORITA Department of Applied Mechanics and Aerospace Engineering Waseda University 3-4-1 Okubo Shinjuku Graduate Student Graduate School of Science and Engineering Waseda University 3-4-1 Okubo Shinjuku

Unsteady behaviors as well as unsteady cascade flow fields of a single-stage axial flow compressor were experi- mentally investigated by detail measurements of unsteady performance characteristics and casing wall pressure and internal flow velocity fluctuations. The main feature of the test compressor is a capacity tank connected di- rectly to the compressor outlet in series through slits and a concentric duplex pipe, and also jet nozzles in order to inject compressed air toward the rotor tip region. Research attention is focused on the post-stall characteristics of surge and rotating stall which occur simultaneously. When the compressor was connected to the capacity tank, surge was generated with rotating stall in accordance with the capacitance increment of whole compressor system The surge behavior changed irregularly with throttling valve installed behind the compressor, and several types of surge cycles were observed. In addition, the surge cycle changed by jet injection to the rotor tip region. The re- suits suggested that the blockages of the cascade flow which were generated by a stall cell play an important role in deciding the surge behaviors.

关键词： Axial flow compressor Surge Rotating stall Stall cell Jet injection

Deviation of congruent composition in Fe-Pd system

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Rare Metals 2006年第5期25卷 393-398页

作者： Tetsuo Mohri daisuke Hamajima Ying Chen Division of Materials Science and Engineering Graduate School of Engineering Hokkaido University Kita-13 Nishi-8 Kita-ku Sapporo 060-8628Japan Department of Quantum Engineering and System Science Graduate School of Engineering University of Tokyo Hongo 7-3-1 Bunkyo-ku Tokyo113-8656 Japan

The first-principles calculation of the disordered Ll0 phase boundary for the Fe-Pd system is attempted by combining the FLAPW electronic structure total energy calculations and the cluster variation method via the cluster expansion method. The lattice vibration effects are taken into account based on the Debye-Gruneisen model within quasi-harmonic approximation. The transition temperature is reproduced with very high accuracy. However, the experimental congruent composition of disordered L10 phase that significantly deviates from 1.＂ 1 stoichiometry is not reproduced. Fulther calculations are attempted based on the phenomenological Lennard-Jones type pair potential, which is capable of introducing both tetragonality of the Ll0 ordered phase and additional configurational freedom because of the magnetic spins. The prelimi- nary calculations indicate that the tetragonality enhances the stability of the L10 ordered phase and the magnetic contributions also change the transition temperature. Despite these findings, the shift of the congruent composition still remains as a subject that needs further research. The electronic origin of the shifting of the congruent composition is briefly discussed.

关键词： Fe-Pd alloy system order-disorder phenomena phase diagrams ab initio calculation

Dilute long period stacking/order(LPSO)-variant phases along the composition gradient in a Mg-Ho-Cu alloy

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Journal of Magnesium and Alloys 2022年第6期10卷 1573-1580页

作者： Kai Guan daisuke Egusa Eiji Abe Department of Materials Science and Engineering The University of TokyoTokyo 113-8656Japan Research Center for Structural Materials National Institute for Materials ScienceTsukuba 305-0047Japan

We have systematically investigated the microstructures of as-cast Mg_(97.49)Ho_(1.99)Cu_(0.43)Zr_(0.09)alloy by atomic resolution high-angle annular dark field scanning transmission electron microscopy(HAADF-STEM), revealing the coexistence of 18R, 14H and 24R long period stacking/order(LPSO) phases with fully coherent interfaces along step-like composition gradient in a blocky intermetallic compound distributed at grain boundary. The short-range order(SRO) L1_(2)-type Cu_(6)Ho_(8)clusters embedded across AB’C’A-stacking fault layers are directly revealed at atomic scale. Importantly, the order degree of SRO clusters in the present dilute alloy is significant lower than previous 6M and 7M in-plane order reported in ternary Mg-TM(transition metal)-RE(rare earth) alloys, which can be well matched by 9M in-plane order. This directly demonstrates that SRO in-plane L1_(2)-type clusters can be expanded into more dilute composition regions bounded along the definite TM/RE ratio of 3/4. In addition, the estimated chemical compositions of solute enriched stacking fault(SESF) in all LPSO variants are almost identical with the ideal SESF composition of 9M in-plane order, regardless of the type of LPSO phases. The results further support the viewpoint that robust L1_(2)-type TM_(6)RE_(8)clusters play an important role in governing LPSO phase formation.

关键词： Magnesium alloys Long period stacking/order(LPSO)phases Short-range order(SRO)clusters High-angle annular dark field scanning transmission electron microscopy(HAADF-STEM)

Attenuation and Distortion of Compression Waves Propagating in Very Long Tube

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Journal of Thermal Science 2011年第1期20卷 53-57页

作者： Shinya NAKAMURA daisuke SASA Toshiyuki AOKI Graduate School of Engineering Sciences Kyushu UniversityKasugaFukuoka816-8580Japan

A lot of phenomena related to propagating various waves are seen when the high-speed train goes through the tunnel,the gas pipeline is broken due to an accident or the air brake of the wagon *** instance,a compression wave generated ahead of a high-speed train entering a tunnel propagates to the tunnel exit and spouts as a micro pressure wave,which causes an exploding *** order to estimate the magnitude correctly,the mechanism of the attenuation and distortion of a compression wave propagating along a very long tunnel must be understood and the experimental information on these phenomena is *** experimental investigation is carried out to clarify the attenuation and distortion of the propagating compression wave in a very long *** results show that the strength of a compression wave decreases with *** attenuation and distortion of compression waves are affected by the initial waveform of the compression wave and by the unsteady boundary layer induced by the propagating *** shape of a compression wave becomes different with the propagating distance;that is,a shock wave appears just head of a wavefront and an overshoot on pressure distribution is observed behind a shock wave due to the transition of the unsteady boundary layer.

关键词： Propagating Compression Wave Very Long Tube Micro-pressure Wave High-Speed Train

Assessment of physical stress during the perioperative period of endoscopic submucosal dissection

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World Journal of Gastroenterology 2022年第32期28卷 4508-4515页

作者： daisuke Chinda Tadashi Shimoyama Department of Gastroenterology Hirosaki University Graduate School of MedicineHirosaki 036-8562Japan Division of Endoscopy Hirosaki University HospitalHirosaki 036-8563Japan Department of Internal Medicine Aomori General Health Examination CenterAomori 030-0962Japan

The advantage of endoscopic submucosal dissection(ESD)is that it is less invasive than *** is one of the best treatments for older patients as surgery in this age group of patients is ***,it is unclear how much lower the physical stress of ESD is compared with that of ***,objective methods are required to assess physical stress in patients who have undergone *** current review of ESD aimed to summarize the recent advancements in the assessment of physical stress during the perioperative period,focusing on changes in energy metabolism and serum opsonic activity(SOA).Based on metabolic changes,resting energy expenditure(REE)was measured using an indirect *** stress factor calculated from the REE and the basal energy expenditure computed using the Harris-Benedict equation can be used to assess physical *** was assessed using the chemiluminescence method,wherein the use of chemiluminescent probes(i.e.,lucigenin and luminol)allowed quantification of reactive oxygen species generated by *** an auto luminescence analyzer,the results were evaluated based on the maximum light emission and area under the emission *** quantifiable results revealed the minimal invasiveness of ESD.

关键词： Physical stress Endoscopic submucosal dissection Indirect calorimeter Resting energy expenditure Chemiluminescence Serum opsonic activity

Prevalence and characteristics of Kawasaki disease before and during the COVID-19 pandemic

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World Journal of Pediatrics 2021年第2期17卷 215-217页

作者： Rintaro Ono daisuke Hasegawa Department of Pediatrics St.Luke's International Hospital9-1 AkashichoChuo-kuTokyo 104-8560Japan

Kawasaki disease(KD)is a febrile disease with unclear *** far,KD has been considered to be trig-gered,at least in part,by an infection[1].In 2020,corona-virus disease 2019(COVID-19)became a global pandemic and lifestyles changed ***,the preva-lence of common infection has decreased *** epidemiological change prompted us to postulate that major variations of common pediatric infections would affect the incidence of KD.

关键词： prompt characteristics Kawasaki

Impacts of invasive Iris pseudacorus L.(yellow flag) establishing in an abandoned urban pond on native semi-wetland vegetation

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Journal of Integrative Agriculture 2018年第8期17卷 1881-1887页

作者： daisuke Hayasaka Shingo Fujiwara Taizo Uchida Graduate School of Agriculture KINDAI University Faculty of Engineering Kyushu Sangyo University

Iris pseudacorus L., intentionally introduced in Japan as an ornamental plant and to improve aquatic environments, has been declared a noxious species in the Invasive Alien Species Act of Japan due to the suspected high ecological risks to the local species and ecosystems. Although prompt responses to I. pseudacorus have been sought to conserve local biodiversity, knowledge about its invasiveness is lacking. Here, we report the relationship between the establishment of I. pseudacorus and floristic changes in semi-wetland vegetation of an abandoned urban pond(Aoike), Nara City, Nara Prepecture, Japan. In total, 64 vascular plants were recorded in the pond, of which 50 were native species, seven were naturalized non-native, and seven were invasive species. On the other hand, most of these vascular plants(42 species) were grassland species and only several aquatic plants(10 species) were found in this study pond. The number of vascular plant species decreased significantly at quadrats with a coverage of I. pseudacorus above 50%. In addition, tendencies of lower number of native species and concomitant higher number of invasive species were found with increasing coverage of I. pseudacorus. From these results, we suggest that it is important to preferentially manage sites where the coverage of I. pseudacorus is above 50%, in order to preserve the local biodiversity. Additionally, as recommended in the literature, it is essential that the cut reproductive organs are kept submerged under deep water for an effective control of I. pseudacorus.

关键词： biodiversity conservation biological invasions ecological impacts exotic species hydrophytes species traits

Model predictive control for hybrid vehicle ecological driving using traffic signal and road slope information

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Control Theory and Technology 2015年第1期13卷 17-28页

作者： Kaijiang YU Junqi YANG daisuke YAMAGUCHI School of Electrical Engineering and Automation Henan Polytechnic University School of Information Science and Electrical Engineering Kyushu University

This paper presents development of a control system for ecological driving of a hybrid vehicle. Prediction using traffic signal and road slope information is considered to improve the fuel economy. It is assumed that the automobile receives traffic signal information from intelligent transportation systems （ITS）. Model predictive control is used to calculate optimal vehicle control inputs using traffic signal and road slope information. The performance of the proposed method was analyzed through computer simulation results. Both the fuel economy and the driving profile are optimized using the proposed approach. It was observed that fuel economy was improved compared with driving of a typical human driving model.

关键词： Ecological driving model predictive control intelligent transportation systems traffic signal optimal control

Stress-dependent shear wave splitting and permeability in fractured porous rock

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 1-11页

作者： daisuke Katsuki Marte Gutierrez Abdulhadi Almrabat Petroleum Engineering Department Colorado School of Mines Department of Civil and Environmental Engineering Colorado School of Mines

It is well known that shear wave propagates slower across than parallel to a fracture, and as a result, a travelling shear wave splits into two directions when it encounters a fracture. Shear wave splitting and permeability of porous rock core samples having single fracture were experimentally investigated using a high-pressure triaxial cell, which can measure seismic shear wave velocities in two directions mutually perpendicular to the sample axis in addition to the longitudinal compressive wave velocity. A single fracture was created in the samples using a modified Brazilian split test device, where the cylindrical sample edges were loaded on two diametrically opposite lines by sharp guillotines along the sample length. Based on tilt tests and fracture surface profilometry, the method of artificially induced tensile fracture in the sample was found to create repeatable fracture surfaces and morphologies. Seismic velocities of the fractured samples were determined under different levels of stress confinement and fracture shear displacement or mismatch. The effective confining stress was varied from 0.5 MPa to55 MPa, while the fractures were mismatched by 0 mm, 0.45 mm and 1 mm. The degree of matching of the fracture surfaces in the core samples was evaluated using the joint matching coefficient(JMC). Shear wave splitting, as measured by the difference in the magnitudes of shear wave velocities parallel(V_(S1))and perpendicular(V_(S2)) to the fracture, is found to be insensitive to the degree of mismatching of the fracture joint surfaces at 2 MPa, and decreased and approached zero as the effective stress was *** models for the stress-and JMC-dependent shear wave splitting and fractured rock permeability were developed based on the experimental observations. The effects of the joint wall compressive strength(JCS), JMC and stress on the stress dependency of joint aperture were discussed in terms of hydro-mechanical response. Finally, a useful relationship

关键词： Fractured rock Sandstone Stress dependency Shear wave splitting Wave velocity Permeability Fracture stiffness Elastic modulus