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Self-excited oscillation of spinning solar sails utilizing solar radiation pressure

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Astrodynamics 2020年第3期4卷 177-192页

作者： yuki takao Osamu Mori Jun'ichiro Kawaguchi Department of Aeronautics and A stronautics The University of TokyoTokyo 113-8654Japan Institute of Space and Astronartical Science Japan Aerospace Exploration AgencySagamihara 252-5210Japan

The present paper proposes a control method to excite spinning solar sail membranes for three-dimensional *** optical property switching,the input is given as the change in magnitude of the solar radiation *** resonance point of this system varies with the vibration state due to its nonlinearity and the change in equilibrium *** deal with this,a state feedback control law that automatically tracks the resonance point is developed in the present *** proposed method enables decentralized control of the actuators on the sail,each of which determines the control input independently using only the information of vibration *** proposed method is validated using numerical *** results show that the nonlinear system behaves differently from the linear system,and the vibration grows using the decentralized control regardless of resonance point variation.

关键词： solar sail solar radiation pressure vibration mode self-excited oscillation mechanical resonance decentralized control

Improvement of sail storage and deployment mechanism for spin-type solar power sail

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Astrodynamics 2020年第3期4卷 223-231页

作者： Osamu Mori Nobukatsu Okuizumi Toshihiro Chujo yuki takao Institute of Space and A stronautical Science Japan A erospace Exploration AgencySagamihara 252-5210Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan Department of Aeronautics and Astronautics the University of TokyoTokyo 113-8654Japan

Deployable membrane structures are expected to be used for large area space structures,such as solar propulsion sails,magnetoplasma sails,drag-deorbiting sails,membrane antennas,and solar power *** are lightweight and can be compactly stored at *** achievement of the Japan Aerospace Exploration Agency(JAXA)was the successful deployment of a 200 m2 sail using centrifugal force in the IKAROS mission,which was the first solar propulsion sail-craft in *** has long been studying the technology of spin deployment of sail membranes,and is currently planning the spin deployment of a class sail larger than 2000 m2 as the next step in the development of the IK AROS *** paper discusses the unexpected behaviors during on-orbit sail deployment by IKAROS,as well as problems with the sail holding method,and proposes an improved sail storage structure and deployment mechanism for the OKEANOS mission.

关键词： solar sail solar power sail storage deployment IKAROS OKEANOS

Solar power sail mission of OKEANOS

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Astrodynamics 2020年第3期4卷 233-248页

作者： Osamu Mori Jun Matsumoto Toshihiro Chujo Masanori Matsushita Hideki Kato Takanao Saiki Yuichi Tsuda Jun'ichiro Kawaguchi Fuyuto Terui Yuya Mimasu Go Ono Naoko Ogawa yuki takao yuki Kubo Kaoru Ohashi Ahmed Kiyoshi Sugihara Tatsuaki Okada Takahiro Iwata Hajime Yano Japan Aerospace Exploration Agency Sagarmihara 252-5210Japan Tokyo Institute of Technology Tokyo 152-8550Japan The University of Tokyo Tokyo 113-8654Japan Patchedconics LLCSagarmihara 252-5210Japan

The solar power sail is an original Japanese concept in which electric power is generated by thin-film solar cells attached on the solar sail *** Aerospace Exploration Agency(JAXA)successfully demonstrated the world’s first solar power sail technology through IKAROS(Interplanetary Kite-craft Accelerated by Radiation of the Sun)mission in *** demonstrated photon propulsion and power generation using thin-film solar cells during its interplanetary *** up,solar power sails can generate enough power to drive high specific impulse ion thrusters in the outer planetary *** this concept,we propose a landing or sample return mission to directly explore a Jupiter Trojan asteroid using solar power sail-craft OKEANOS(Oversize Kite-craft for Exploration and AstroNautics in the Outer Solar System).After rendezvousing with a Trojan asteroid,a lander separates from OKEANOS to collect samples,and perform in-situ analyses in three proposed mission sequences,including sending samples back to *** paper proposes a system design for OKEANOS and includes analyses of the latest mission.

关键词： solar power sail Trojan asteroid landing in-situ analysis outer solar system OKEANOS

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 *** decades,conventional cancer treatments used a one-size-fits-all approach,overlooking the intricate genetic variations that drive *** emergence of cancer genomics has ushered in a new era of personalized and targeted cancer *** Human Genome Project,which was launched in 1990 and completed in 2003。

关键词： cancer Cancer annually

Psychological potential field and human eye fixation on binary line-drawing images: A comparative experimental study

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Computational Visual Media 2020年第2期6卷 205-214页

作者： Naoyuki Awano yuki Hayashi Osaka University of Economics OsakaOsaka533-8533Japan Osaka Prefecture University SakaiOsaka599-8531Japan

Quantitatively evaluating the psychological and perceptual effects of objects is an important issue,but is difficult. In cognitive studies, the psychological potential field(PPF), which represents psychological intensities in vision and can be calculated by applying computational algorithms to digital images, may help with this issue. Although studies have reported using the PPF to evaluate psychological effects, such as impressions, detailed investigations on how the PPF represents psychological perception and its limitations have not yet been performed. Another relevant tool is the fixation map, which visualizes human eye fixations;this map is generated from actual measurements acquired by eye-tracking and does not represent psychological effects directly. Although the PPF and the fixation map are based on visual imaging, they have never been compared. In this paper, we do so for the first time, using psychological and perceptual properties of line-drawing images. The results demonstrate the difference between these methods, including their representation of different properties with respect to visual perception. Moreover, the similarity between the two methods highlights the possibility of assessing perceptual phenomena such as categorization and cognition of objects based on human vision.

关键词： psychological potential field(PPF) eye fixation eye-tracking visual perception line drawing

Regulation of Vascular Development by CLE Peptide-receptor Systems

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Journal of Integrative Plant Biology 2010年第1期52卷 8-16页

作者： yuki Hirakawa yuki Kondo Hiroo Fukuda Department of Biological Sciences Graduate School of ScienceThe University of Tokyo

Cell division and differentiation of stem cells are controlled by non- cell-autonomous signals in higher organisms. The plant vascular meristem is a stem-cell tissue comprising procambial cells that produce xylem cells on one side and phloem cells on the other side. Recent studies have revealed that TDIF （tracheary element differentiation inhibitory factor）/CLE41/CLE44 peptide signal controls the procambial cell fate in a non-cell-autonomous manner. TDIF produced in and secreted from phloem cells is perceived by TDR/PXY, a leucine-rich repeat receptor kinase located in the plasma membrane of procambial cells. This signal suppresses xylem cell differentiation of procambial cells and promotes their proliferation. In addition to TDIF, some other CLE peptides play roles in vascular development. Here, we summarize recent advances in CLE signaling governing vascular development.

关键词： TDIF Regulation of Vascular Development by CLE Peptide-receptor Systems

Visualization study on the coarse graining DEM for large-scale N gas-solid flow systems

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Particuology 2021年第6期19卷 24-33页

作者： yuki Mori Mikio Sakai Department of Nuclear Engineering and Management School of EngineeringThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan Resilience Engineering Research Center School of EngineeringThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan

Gas-solid flows are ubiquitous in industrial *** coupled model of the discrete element method(DEM)and computational fluid dynamics(CFD)is one of the techniques for the simulation of the gas-solid *** enhance the applicability of the DEM-CFD method,the coarse graining DEM has been developed to simulate large-scale powder *** coarse graining DEM is a scaling law model and hence can simulate large-scale systems using a smaller number of particles than the actual *** the coarse graining DEM enables to effectively simulate large-scale powder systems on a single PC,visualized image is lack of reality due to reduced spatial *** a novel visualization method is developed to produce realistic *** the proposed technique,the virtual particles are located by considering the motion and location of the coarse grain *** show the adequacy of the proposed method,two types of visualization based on the computational results are made:a blow-up of powder due to injected gas flow and a spouted *** these systems,the visualized images are shown to be improved by the proposed visualization *** effectiveness of the proposed method is proved by the agreement of the images based on the calculation results between the standard DEM-CFD method and coarse graining DEM.

关键词： DEM-CFD method Coarse graining DEM Computer graphics

Pseudogap,Fermi arc,and Peierls-insulating phase induced by 3D-2D crossover in monolayer VSe2

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Nano Research 2019年第1期12卷 165-169页

作者： yuki Umemoto Katsuaki Sugawara yuki Nakata Takashi Takahashi Takafumi Sato Department of Physics Tohoku UniversitySendai 980-8578Japan WPI-Advanced Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Center for Spintronics Research Network Tohoku UniversitySendai 980-8577Japan

One of important challenges in condensed-matter physics is to realize new quantum states of matter by manipulating the dimensionality of materials,as represented by the discovery of high-temperature superconductivity in atomic-layer pnictides and room-temperature quantum Hall effect in *** sition-metal dichalcogenides(TMDs)provide a fertile platform for exploring novel quantum phenomena accompanied by the dimensionality change,since they exhibit a variety of electronic/magnetic states owing to quantum *** we report an anomalous metal-i nsulator transition in duced by three-dimensional(3D)-two-dimensional(2D)crossover in mono layer 1T-VSe2 grown on bilayer *** observed a complete insulating state with a finite energy gap on the entire Fermi surface in monolayer 1T-VSe2 at low temperatures,in sharp contrast to metallic nature of *** surprisingly,monolayer 1T-VSe2 exhibits a pseudogap with Fermi arc at temperatures above the charge-density-wave temperature,showing a close resemblanee to high-temperature *** similarity suggests a common underlying physics between two apparently different systems,pointing to the importance of charge/spin fluctuations to create the novel electronic states,such as pseudogap and Fermi arc,in these materials.

关键词： transition-metal dichalchogenides 1T-VSe2 charge density wave electronic states pseudogap Fermi arc

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 *** 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 ***,controlling them becomes challenging due to their large number of inputs,leading previous researchers to impose strong constraints to limit their potential control *** study focuses on novel attitude control techniques for transformable spacecraft under *** developed two methods,namely,joint angle optimization to obtain arbitrary SRP force and torque,and momentum damping control driven by joint angle *** 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 *** validity of our proposed method is confirmed through numerical *** 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