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Experimental study on slender buckling-restrained knee braces with round steel bar cores

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Frontiers of Structural and Civil engineering 2023年第1期17卷 99-121页

作者： Togtokhbuyan MUNKHUNUR Hiroshi TAGAWA Xingchen CHEN graduate school of engineering Hiroshima UniversityHigashi-Hiroshima 739-8527Japan graduate school of Advanced science and engineering Hiroshima UniversityHigashi-Hiroshima 739-8527Japan

This study aimed to investigate a novel slender buckling-restrained knee brace damper (BRKB) for welded and weld-free steel framing systems. The proposed BRKB adopts steel bar cores connected by a central coupler and restrained by tube buckling restrainers with a cover tube supporter. The advantages of the proposed damper include easy assembly compared to conventional buckling restrained braces, and high architectural flexibility for the retrofitting of large-span weld-free or welded steel moment-resisting systems. Specifically, by increasing the number of contraction allowances, undesirable failure mechanisms that are global instability and local buckling of the restrainer ends can be effectively suppressed because the more uniform plastic deformation of the core bar can be achieved longitudinally. In this study, displacement-controlled compression and cyclic loading tests were carried out to investigate the deformation capacities of the proposed BRKBs. Structural performance metrics associated with both loading tests, such as strength capacities, strains at the cover tubes and buckling restrainers, and hysteretic behaviors of the proposed damper under cyclic loads, were measured and discussed. Test results revealed that the geometrical characteristics of the cover tubes and adopted contraction allowances at the dampers play essential roles in their load-bearing capacities.

关键词： weld-free beam-to-column connections moment-resisting frame cyclic and compression loading tests buckling-restrained knee brace cover tube

SiC_p及Al_2O_(3w)增强铸态混杂金属基复合材料的疲劳裂纹扩展机理(英文)

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Transactions of Nonferrous Metals Society of China 2014年第S1期24卷 1-13页

作者： AKM Asif IQBAL Yoshio ARAI Wakako ARAKI graduate school of science and engineering Saitama University Division of Mechanical engineering and science Graduate School of Science and EngineeringSaitama University

研究了一种SiCp及Al2O3w增强铸态混杂金属基复合材料(MMC)的疲劳裂纹扩展(FCG)机理,同时对比研究了Al2O3w增强铸态金属基复合材料和铸态铝合金的疲劳裂纹扩展机理。在研究近临界和裂纹稳定扩展区域的疲劳裂纹扩展(FCG)机理时,发现混杂MM... 详细信息

研究了一种SiCp及Al2O3w增强铸态混杂金属基复合材料(MMC)的疲劳裂纹扩展(FCG)机理,同时对比研究了Al2O3w增强铸态金属基复合材料和铸态铝合金的疲劳裂纹扩展机理。在研究近临界和裂纹稳定扩展区域的疲劳裂纹扩展(FCG)机理时,发现混杂MMC的临界应力强度因子?Kth值高于其他两种材料的?Kth值,说明应力强度因子?K值较低时混杂MMC可以更好地抵抗裂纹扩展。随着?K值的降低,两种MMC在近临界区域显示出相似的FCG机理,即主要由增强相–基体界面的剥离控制,随后由铝基体中空隙的形核与合并控制;在裂纹稳定或中等扩展区域,?K值较高时FCG除了受界面上周期性裂纹扩展引起的增强相–基体界面剥离的影响之外,还显著受到铝基体中疲劳条带的影响。此外,在高?K值下,因为局部失稳断裂机制,可见铝基体中空隙的形核与合并以及SiCp和Al2O3w中的穿晶断裂。对于铸态铝合金,在低?K值下,FCG主要受空隙的形核与合并所控制;在高?K值下,FCG主要受铝晶粒的疲劳条带控制,随后受Si团簇中空隙的形核与合并控制。

关键词：铸态金属基复合材料疲劳裂纹扩展应力强度因子断裂

Platinum–P(BFPy) 3 -catalyzed regioselective diboration of terminal alkynes with (pin)B–B (aam)

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Organic Chemistry Frontiers 2022年第5期9卷 1370-1374页

作者： Ikuo Kageyuki Jialun Li Hiroto Yoshida graduate school of Advanced science and engineering Hiroshima UniversityHigashi-Hiroshima 739-8526Japan

An unsymmetrical diboron,(pin)B–B(aam),is smoothly added across a carbon–carbon triple bond of various terminal alkynes under platinum catalysis,resulting in the regio-and stereoselective formation of cis-vic-diborylalkenes via B(aam)-installation at the terminal carbon.The use of a highly electron-deficient triarylphosphine ligand,P(BFPy)_(3),is indispensable for the regiocontrol,and electron-deficiency in ligands has been proven to be closely correlated with the regioselectivity.

关键词： smoothly catalyzed boron

The early Japanese books reorganization by combining image processing and deep learning

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CAAI Transactions on Intelligence Technology 2022年第4期7卷 627-643页

作者： Bing Lyu Hengyi Li Ami Tanaka Lin Meng graduate school of science and engineering Ritsumeikan UniversityKusatsuShigaJapan College of science and engineering Ritsumeikan UniversityKusatsuShigaJapan

Many early Japanese books record a large amount of information,including historical politics,economics,culture,and so on,which are all valuable legacies.These books are waiting to be reorganized at the moment.However,a large amount of the books are described by Kuzushiji,a type of handwriting cursive script that is no longer in use today and only readable by a few experts.Therefore,researchers are trying to detect and recognise the characters from these books through modern techniques.Unfortunately,the characteristics of the Kuzushiji,such as Connect-Separate-characters and Manyvariation,hinder the modern technique assisted re-organisation.Connect-Separatecharacters refer to the case of some characters connecting each other or one character being separated into unconnected parts,which makes character detection hard.Manyvariation is one of the typical characteristics of Kuzushiji,defined as the case that the same character has several variations even if they are written by the same person in the same book at the same time,which increases the difficulty of character recognition.In this sense,this paper aims to construct an early Japanese book reorganisation system by combining image processing and deep learning techniques.The experimentation has been done by testing two early Japanese books.In terms of character detection,the final Recall,Precision and F-value reaches 79.8%,80.3%,and 80.0%,respectively.The deep learning based character recognition accuracy of Top3 reaches 69.52%,and the highest recognition rate reaches 82.57%,which verifies the effectiveness of our proposal.

关键词： character recognition deep learning image processing Japanese books reorganization Kuzushiji

Removal of estrogens by electrochemical oxidation process

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Journal of Environmental sciences 2014年第6期26卷 1355-1360页

作者： Vo Huu Cong Sota Iwaya Yutaka Sakakibara graduate school of Creative science and engineering Waseda University

Treatments of estrogens such as Estrone （El）, Estradiol （E2） and Ethinylestradiol （EE2） were conducted using an electrolytic reactor equipped with multi-packed granular glassy carbon electrodes. Experimental results showed that El, E2 and EE2 were oxidized in the range of 0.45-0.85 V and were removed through electro-polymerization. Observed data from continuous experiments were in good agreement with calculated results by a mathematical model constructed based on mass transfer limitation. In continuous treatment of trace estrogens （1 μg/L）, 98% of El, E2 and EE2 were stably removed. At high loading rate （100 μg/L）, removal efficiency of E1 was kept around 74%-88% for 21 days, but removal efficiency reduced due to passivation of electrodes. However, removal efficiency was recovered after electrochemical regeneration of electrodes in presence of ozone. Electric energy consumption was observed in the range of 1-2 Wh/m3. From these results, we concluded that the present electrochemical process would be an alternative removal of estrogens.

关键词： electro-polymerization electrode regeneration endocrine disrupting chemicals estrogen granular reactor

Organic photocatalysts:From molecular to aggregate level

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Nano Research 2022年第5期15卷 3835-3858页

作者： Chuxuan Yan Jiaqi Dong Yingzhi Chen Wenjie Zhou Yu Peng Yue Zhang Lu-ning Wang school of Materials science and engineering University of Science and Technology BeijingBeijing 100083China Shunde graduate school of University of science and Technology Beijing Foshan 528399China

Organic semiconductors(OSCs)have the advantages of tunable molecular structures,suitable band gaps,and exceptional optoelectronic properties.The π-π stacking ability of OSCs also leads to appealing molecular stacking structure,function,and stability.So far,organic photocatalysts have engaged in homogeneous or heterogeneous photocatalysis in the form of free molecules,supported molecules,or nanostructures.Meanwhile,researches on organic photocatalysts have expanded from small organic molecules to the organic macromolecules,as well as their various nanostructures and nanocomposites including isolated zero-dimensional(0D),one-dimensional(1D),two-dimensional(2D),three-dimensional(3D)nanostructures,and their combinations.Therefore,many versatile strategies have been explored to improve photocatalytic ability and practicality either from molecular synthetic modification,crystal,or interface engineering.In this review,we first discuss the photophysical and photochemical processes of organic photocatalysts that govern the ultimate photocatalytic efficiency;we then summarize different forms of organic photocatalysts,their rational design strategies,and mechanistic pathways,as well as their applications in H_(2) evolution,CO_(2) reduction,and environmental purification,aiming to highlight the structure/property relationships;we lastly propose ongoing directions and challenges for future development of organic photocatalysts in real use.

关键词： organic photocatalyst homogeneous photocatalysis heterogeneous photocatalysis nanostructure heterostructure

Key-Value Store Coupled with an Operating System for Storing Large-Scale Values

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Computers, Materials & Continua 2022年第11期73卷 3333-3350页

作者： Jeonghwan Im Hyuk-Yoon Kwon graduate school of Data science Seoul National University of Science and TechnologySeoulKorea Department of Industrial engineering Graduate School of Data ScienceResearch Center for Electrical and Information ScienceSeoul National University of Science and TechnologySeoulKorea

The key-value store can provide flexibility of data types because it does not need to specify the data types to be stored in advance and can store any types of data as the value of the key-value pair.Various types of studies have been conducted to improve the performance of the key-value store while maintaining its flexibility.However,the research efforts storing the large-scale values such as multimedia data files(e.g.,images or videos)in the key-value store were limited.In this study,we propose a new key-value store,WR-Store++aiming to store the large-scale values stably.Specifically,it provides a new design of separating data and index by working with the built-in data structure of the Windows operating system and the file system.The utilization of the built-in data structure of the Windows operating system achieves the efficiency of the key-value store and that of the file system extends the limited space of the storage significantly.We also present chunk-based memory management and parallel processing of WR-Store++to further improve its performance in the GET operation.Through the experiments,we show that WR-Store++can store at least 32.74 times larger datasets than the existing baseline key-value store,WR-Store,which has the limitation in storing large-scale data sets.Furthermore,in terms of processing efficiency,we show that WR-Store++outperforms not only WR-Store but also the other state-ofthe-art key-value stores,LevelDB,RocksDB,and BerkeleyDB,for individual key-value operations and mixed workloads.

关键词： Key-value stores large-scale values chunk-based memory management parallel processing

材料基因组工程:一种有前途的高性能金属有机框架研发方法

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science Bulletin 2022年第12期67卷 1197-1200页

作者：薛祥东黄秀兵王戈 Advanced Innovation Center for Materials Genome engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Shunde graduate school University of Science and Technology BeijingShunde 528399China

The“modular”structural features of metal–organic frameworks(MOFs),that is,inorganic nodes and organic ligands that are used as building blocks and assembled according to a certain topology,endow MOFs with an almost... 详细信息

关键词：金属有机框架 inorganic topology

Diffusion and collective motion of rotlets in 2D space

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Chinese Physics B 2020年第6期29卷 37-43页

作者： Daiki Matsunaga Takumi Chodo Takuma Kawai Graduate School of Engineering Science Osaka University5608531 OsakaJapan

We investigate the collective motion of rotlets that are placed in a single plane. Due to the hydrodynamic interactions,the particles move through the two-dimensional(2D) plane and we analyze these diffusive motions. By analyzing the scaling of the values, we predict that the diffusion coefficient scales with φ0.5, the average velocity with φ, and relaxation time of the velocity autocorrelation function with φ-1.5, where φ is the area fraction of the particles. In this paper, we find that the predicted scaling could be seen only when the initial particle position is homogeneous. The particle collective motions are different by starting the simulation from random initial positions, and the diffusion coefficient is the largest at a minimum volume fraction of our parameter range, φ = 0.05. The deviations based on two initial positions can be explained by the frequency of the collision events. The particles collide during their movements and the inter-particle distances gradually increase. When the area fraction is large, the particles will result in relatively homogeneous configurations regardless of the initial positions because of many collision events. When the area fraction is small(φ < 0.25), on the other hand, two initial positions would fall into different local solutions because the rare collision events would not modify the inter-particle distances drastically. By starting from the homogeneous initial positions, the particles show the maximum diffusion coefficient at φ≈ 0.20. The diffusion coefficient starts to decrease from this area fraction because the particles start to collide and hinder each other from a critical fraction ~23%. We believe our current work contributes to a basic understanding of the collective motion of rotating units.

关键词： rotlet diffusion Stokes flow