检索结果-内蒙古大学图书馆

Formation of grid patterns in an ac-driven electroconvection system

Physical Review E 2020年第6期101卷 062701-062701页

作者： Jong-Hoon Huh Haruki Osoguchi Department of Physics and Information Technology Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Fukuoka 820-8502 Japan

We report the formation mechanism of a unique pattern observed in ac-driven electroconvection of nematic liquid crystals (NLCs), in which many well-organized grid cells are very regularly aggregated in a two-dimensional plane, globally forming a nearly perfect grid pattern (GP). Intuitively, the formation of such a pattern is unpredictable; usually, the perfectly regular normal roll (NR) showing a preferred roll direction is observed in this system by imposing a fixed initial direction of an NLC. The GP was investigated by varying the ac voltage and frequency. To characterize the GP, the density ρGP, the width a and length b of the grids, and the oscillation period TGP of an inner optical pattern of the grids were measured; moreover, the lengths L¯x and L¯y characterizing phase-jump lines (PJLs) in the GP were examined. By taking into account the process of evolution from a fluctuating NR with defects to the GP, the velocity and director fields of the GP are estimated. Furthermore, in comparison with the bimodal mechanism proposed in the earlier study, a possible mechanism for the GP formed by the PJLs is discussed; various routes to GPs depending on the ac frequency are proposed.

关键词： Convection Dissipative dynamics Pattern formation Phase diagrams Liquid crystals

来源：评论

学校读者我要写书评

暂无评论

Characterization of surface anchoring energy of nematic liquid crystals via electrohydrodynamic instability

引用

Physical Review E 2020年第6期101卷 062703-062703页

作者： Dae Geon Ryu Jong-Hoon Huh Young-Ki Kim Jin Seog Gwag Department of Physics Yeungnam University 280 Daehak-Ro Gyeongsan 38541 Republic of Korea Department of Mechanical Information Science and Technology Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka Fukuoka 820–8502 Japan Department of Chemical Engineering Pohang University of Science and Technology 67 Cheongam-ro Pohang Gyeongbuk 37673 Republic of Korea

Herein, a method is proposed to determine the azimuthal anchoring energies of surface liquid crystals (LCs), as they gradually change orientation from a vertical to a horizontal state owing to an increase in the voltage applied to each LC cell. The LC cells are characterized using the direction of the Williams roll pattern related to the midplane LC director of the conduction regime of the electrohydrodynamic convection patterns of LCs. The application of the midplane LC directions, obtained from the direction of the roll patterns, to the Ericksen-Leslie equation produces the precise values of the surface anchoring strength. The hybrid type 90°-twisted nematic LC cell, composed of homeotropic and homogeneous LC alignment layers on the top and bottom substrates, respectively, was used to find the azimuthal anchoring energy of the surface LCs, indicated by voltages at the initially vertically aligned LC state. It was observed that the surface azimuthal anchoring energy on the homeotropic layer increased with an increase in voltage. We expect that the proposed technique may be excellent in terms of ease of use, simplicity, and accuracy because the azimuthal anchoring energy can be visually evaluated through the roll pattern.

关键词： Liquid-liquid interfaces Nematic liquid crystals

来源：评论

学校读者我要写书评

暂无评论

Preliminary Experiments of Series Elastic Actuator Prototype utilizing Mechanical Resonance

Preliminary Experiments of Series Elastic Actuator Prototype...

引用

International Conference on Control, Automation and systems ( ICCAS)

作者： Akihiro Yoshimi Tsuyoshi Mori Jun Kobayashi Graduate School of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka Japan Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka Japan

This study proposes large force generation by a robotic manipulator by means of providing series elastic actuators exploiting mechanical resonance to it instead of powerful actuators. To this end, the authors designed and assembled a prototype of series elastic actuator that resonates at around 1.0 Hz on the basis of its model and identified parameters, and carried out preliminary experiments with it and a load. The prototype actuator consists of a geared DC motor with an encoder and an elastic element. The elastic element is made of two torsion springs so that it can generate torque in both directions. It was confirmed in the preliminary experiments that the prototype actuator resonated at around 0.7 Hz. In addition, in order to prove efficacy of mechanical resonance for large force generation, output torque of the prototype actuator with the elastic element and without it was estimated using their identified physical parameters and dynamics, and compared them. The estimation results showed that the prototype actuator exploiting mechanical resonance generated 2.24 times larger torque than the one without the elastic element.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Heliocentric Distance Dependence of Zodiacal Light Observed by Hayabusa2#

arXiv

引用

arXiv 2023年

作者： Tsumura, Kohji Matsuura, Shuji Sano, Kei Iwata, Takahiro Yano, Hajime Kitazato, Kohei Takimoto, Kohji Yamada, Manabu Morota, Tomokatsu Kouyama, Toru Hayakawa, Masahiko Yokota, Yasuhiro Tatsumi, Eri Matsuoka, Moe Sakatani, Naoya Honda, Rie Kameda, Shingo Suzuki, Hidehiko Cho, Yuichiro Yoshioka, Kazuo Ogawa, Kazunori Shirai, Kei Sawada, Hirotaka Sugita, Seiji Department of Natural Sciences Faculty of Science and Engineering Tokyo City University Tokyo158-8557 Japan Department of Physics School of Science and Technology Kwansei Gakuin University Hyogo669-1337 Japan Department of Space Systems Engineering School of Engineering Kyushu Institute of Technology Fukuoka804-8550 Japan Institute of Space and Astronautical Science Japan Aerospace Exploration Agency Kanagawa252-5210 Japan Department of Space and Astronautical Science The Graduate University of Advanced Studies Kanagawa240-0193 Japan Department of Computer Science and Engineering The University of Aizu Fukushima965-8580 Japan Planetary Exploration Research Center Chiba Institute of Technology Chiba275-0016 Japan Department of Earth and Planetary Science University of Tokyo Tokyo113-0033 Japan Digital Architecture Research Center National Institute of Advanced Industrial Science and Technology Tokyo135-0064 Japan Instituto de Astrofisica de Canarias University of La Laguna Tenerife Spain Geological Survey of Japan National Institute of Advanced Industrial Science and Technology Ibaraki305-8567 Japan Center for Data Science Ehime University Ehime790-8577 Japan Rikkyo University Tokyo171-8501 Japan Meiji University Kanagawa214-8571 Japan Department of Complexity Science and Engineering University of Tokyo Chiba277-8561 Japan JAXA Space Exploration Center Japan Aerospace Exploration Agency Kanagawa252-5210 Japan Kobe University Hyogo657-8501 Japan

Zodiacal light (ZL) is sunlight scattered by interplanetary dust particles (IDPs) at optical wavelengths. The spatial distribution of IDPs in the Solar system may hold an important key to understanding the evolution of the Solar system and material transportation within it. The number density of IDPs can be expressed as n(r) ∼ r−α, and the exponent α ∼ 1.3 was obtained by previous observations from interplanetary space by Helios 1/2 and Pioneer 10/11 in the 1970s and 1980s. However, no direct measurements of α based on ZL observations from interplanetary space outside Earth’s orbit have been performed since then. Here, we introduce initial results for the radial profile of the ZL at optical wavelengths observed over the range 0.76-1.06 au by ONC-T aboard the Hayabusa2# mission in 2021-2022. The ZL brightness we obtained is well reproduced by a model brightness, although there is a small excess of the observed ZL brightness over the model brightness at around 0.9 au. The radial power-law index we obtained is α = 1.30 ± 0.08, which is consistent with previous results based on ZL observations. The dominant source of uncertainty arises from the uncertainty in estimating the diffuse Galactic light (DGL). © 2023, CC BY.

关键词： Orbits

来源：评论

学校读者我要写书评

暂无评论

Population-based Search Relying on Spatial and/or Temporal Scale-free Behaviors of Individuals

Population-based Search Relying on Spatial and/or Temporal S...

引用

IEEE Symposium Series on Computational Intelligence (SSCI)

作者： Zaixiang Zhang Yunhao Zhu Akihiro Fujiwara Kei Ohinishi Graduate School of Computer Science and System Engineering Kyushu Institute of Technology Kawazu Iizuka Fukuoka Japan

ISBN: (数字)9781728124858

ISBN: (纸本)9781728124865

We develop two types of simple population-based search algorithms that model two types of scale-free behaviors of individuals. The scale-free behavior is a particular behavior of individuals of species that search for food not cooperatively but independently. One type of the scale-free behaviors is that a moving distance of an individual from the present food source follows a power low distribution, which is called the spatial scale-free behavior. The other is that a staying duration of an individual at the preset food source follows a power low distribution, which is called the temporal scale-free behavior. We assume static and dynamic problems in which a position of the best food source (the global optimum) is not changed and changed, respectively. In addition, we assume a special event that individuals near the best food source are probabilistically eliminated. We compare the two search algorithms and show that they are complementary with respect to suitable problems. Therefore, we develop a search algorithm that initially includes both types of individuals in a population and evolutionarily adaptively increases an appropriate type of individuals in it. The algorithm is shown to be not the best but work quite well for any problems used.

关键词： Sociology Statistics Search problems Mathematical model Probabilistic logic Adaptation models Optimization

来源：评论

学校读者我要写书评

暂无评论

Fabrication of arrays of the three-dimensional microstructures on a substrate using the combined etching processes

引用

IEEJ Transactions on Sensors and Micromachines 2018年第6期138卷 263-267页

作者： Murakami, Sunao Yamamoto, Shusuke Araki, Kazuhiro Ito, Takahiro Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology 680-4 Kawazu Iizuka Fukuoka820-8502 Japan

Anisotropic etching is a useful processing method for the fabrication of three-dimensional (3D) microstructures on single crystal silicon (SCS) substrates. In this paper, we have fabricated the arrays of 3D convex microstructures using the combined etching process which includes two types of anisotropic etching process. The arrays of the micropillar structures with vertical sidewalls were firstly fabricated on the substrate surface using deep reactive ion etching (D-RIE) of SCS. Furthermore, anisotropic wet etching of the micropillars was performed in the etching solution and the shape of the additionally-etched 3D microstructures was investigated. We have also suggested the potential of the combined etching process to decrease the fabrication time of the arrays of micro pyramid which are usually fabricated using only the anisotropic wet etching of SCS. © 2018 The institute of Electrical Engineers of Japan.

关键词： Wet etching

来源：评论

学校读者我要写书评

暂无评论

Room-Temperature Charge-to-Spin Conversion from Quasi-2D Electron Gas at SrTiO3-Based Interfaces

引用

physica status solidi (RRL) – Rapid Research Letters 2023年第6期17卷

作者： Utkarsh Shashank Angshuman Deka Chen Ye Surbhi Gupta Rohit Medwal Rajdeep Singh Rawat Hironori Asada X. Renshaw Wang Yasuhiro Fukuma Department of Physics and Information Technology Faculty of Computer Science and System Engineering Kyushu Institute of Technology 680-4 Kawazu Iizuka 820-8502 Japan Birck Nanotechnology Center School of Electrical and Computer Engineering Purdue University West Lafayette IN 47907 USA School of Physical and Mathematical Sciences Nanyang Technological University 637616 Singapore Natural Sciences and Science Education National Institute of Education Nanyang Technological University 637616 Singapore Department of Physics Indian Institute of Technology Kanpur Kanpur 208016 India Graduate School of Sciences and Technology for Innovation Yamaguchi University 2-16-1 Tokiwadai Ube 755-8611 Japan School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore Research Center for Neuromorphic AI hardware Kyushu Institute of Technology Kitakyushu 808-0196 Japan

来源：评论

学校读者我要写书评

暂无评论

Prototype Design of Playback and Search system for Lecture Video Content using Google Cloud API

引用

Procedia computer science 2019年 159卷 1517-1526页

作者： Yoshimasa Ohnishi Shin’nosuke Yamaguchi Yoshiki Shimoikura Kazunori Nishino Hideki Kondo Akihiro Hayashi Kyushu Institute of Technology Learning and Teaching Center 680-4 Kawazu Iizuka Fukuoka 820-8502 Japan Kyushu Institute of Technology Faculty of Computer Science and Systems Engineering 680-4 Kawazu Iizuka Fukuoka 820-8502 Japan Kyushu Institute of Technology Institute of Liberal Arts 680-4 Kawazu Iizuka Fukuoka 820-8502 Japan

Recently, it has become possible to easily use video teaching materials in lectures and exercises using high-performance information terminals. In this study, we design and develop playback functions for lecture videos as learning support using a learning management system. The main feature of the proposed system generates keywords from handwritten characters and lecture speech so that learners can search for playback positions related to keywords. Additionally, it becomes possible to create a highly maintainable system in a short development period using speech recognition and still-image recognition functions available on the internet. In this paper, we describe our prototype implementation and present the results of our initial evaluation. The results demonstrate that, regarding the playback of a lecture video, it is possible to use the keyword search function 20–40 min after the lecture video is released. Moreover, we implemented a playback system using a block function on Moodle so that other teaching material in the course could be viewed simultaneously.

关键词： keyword search handwritten characters lecture video internet service Moodle

来源：评论

学校读者我要写书评

暂无评论

Dynamic A-MPDU adaptation method for airtime fairness in channel bonding-ready WLANs

Dynamic A-MPDU adaptation method for airtime fairness in cha...

引用

IEEE Pacific Rim Conference on Communications, computers and Signal Processing

作者： Yusuke Shimizu Daiki Nobayashi Hitomi Tamura Kazuya Tsukamoto Graduate School of Computer Science and System Engineering Kyushu Institute of Technology Fukuoka Japan Faculty of Engineering Kyushu Institute of Technology Fukuoka Japan Graduate School of Engineering Fukuoka Institute of Technology Fukuoka Japan Faculty of Computer Science and Engineering Kyushu Institute of Technology Fukuoka Japan

Channel bonding is a technology to increase the transmission rate by bundling and using multiple continuous channels. However, the communication performance is likely to degrade frequently due to the channel competition caused by the rapid increase of the wireless LAN devices. Dynamic channel bonding is expected to become the mainstream in the future from the viewpoint of efficient channel utilization even under the severe competitive condition. However, since the implementation of the dynamic channel bonding to real PC and simulator is in the preliminary stage, the detailed performance investigation has not been carried out. None of existing studies examines the performance of the dynamic channel bonding at the frame level with CSMA/CA functions under the diverse channel competition condition. In this study, we first examine the performance of the dynamic channel bonding with CSMA/CA functions through theoretical approach (2 M/M/1/K) from the view point of frame level. In addition, we then implement the channel bonding mechanism into the Scenargie simulator and then verify its effectiveness through the comparison between simulation results and theoretical ones. Simulation results show that the dynamic channel bonding is suffering from the performance degradation due to the performance anomaly problem caused by the airtime unfairness, we thus propose a dynamic A-MPDU adaptation method. We showed that our proposed method can maximize throughput while achieving airtime fairness, irrespective of different patterns of channel competition.

关键词：

来源：评论

学校读者我要写书评

暂无评论

An Asynchronous P system Using Branch and Bound for Minimum Graph Coloring

An Asynchronous P System Using Branch and Bound for Minimum ...

引用

International Symposium on Computing and Networking Workshops (CANDARW)

作者： Kotaro Umetsu Akihiro Fujiwara Graduate School of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka Fukuoka Japan

Membrane computing is a computational model based on activity of cells. Using the membrane computing, a number of computationally hard problems have been solved in a polynomial number of steps using an exponential number of membranes. However, the number of membranes denotes the number of cells from practical point of view, and the reduction of the number of membranes must be considered for using the membrane computing in real world. In this paper, we propose an asynchronous P system with branch and bound for reducing the number of membranes. In addition, we evaluate validity of the proposed P system using computational simulations. The experimental results show the validity and efficiency of the proposed P system with branch and bound.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：