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Visible light responsive photocatalysts developed by substitution with metal cations aiming at artificial photosynthesis

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Frontiers in Energy 2021年第3期15卷 568-576页

作者： yuichi YAMAGUCHI Akihiko KUDO Department of Applied Chemistry Faculty of ScienceTokyo University of ScienceTokyo 162-8601Japan

To solve resource,energy,and environmental issues,development of sustainable clean energy system is strongly *** recent years,hydrogen has been paid much attention to as a clean *** hydrogen production by water splitting using a photocatalyst as artificial photosynthesis is a promising method to solve these *** utilization of visible light comprised of solar light is essential for practical *** strategies,i.e.,doping,control of valence band,and formation of solid solution are often utilized as the useful methods to develop visible light responsive *** minireview introduces the recent work on visible-light-driven photocatalysts developed by substitution with metal cations of those strategies.

关键词： visible light responsive photocatalyst water splitting artificial photosynthesis:metal ion substitution

A combination of tides and nontidal variations in ocean bottom pressure may generate interannual slip fluctuations in the transition zone along a subduction plate interface

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Geodesy and Geodynamics 2023年第1期14卷 43-51页

作者： Yoshiyuki Tanaka Hiromu sakaue Masayuki kano suguru Yabe Department of Earth and Planetary science The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan Graduate school of science Tohoku University6-3Aramaki-aza-aobaAoba-kuSendai980-8578Japan Geological survey of Japan National Institute of Advanced Industrial Science and Technology(AIST)Tsukuba Central 71-1-1 HigashiTsukubaIbaraki 305-8567Japan

The tidal triggering of earthquakes has been studied for many *** discovery of slow earthquakes in the early 2000s,including slow slip,has urged scientists to investigate the tidal responses of these earthquakes due to their sensitivity to weak stress *** studies have shown that slow earthquakes correlate with diurnal and semidiurnal tides and seasonal variations in surface loads more clearly than ordinary ***,little is known about long-term responses to external *** this paper,based on a widely accepted frictional law for faults,a mechanism is proposed by which nontidal variations in ocean bottom pressure,when combined with tides,pro mote the occurrence of slow *** slow earthquakes accompany a slip on the plate interface,this mechanism allows one to estimate slip modulations.A one-degree-of-freedom slip model is constructed and applied to Ise Bay in the Tonankai region of southwestern Japan,where large-scale ocean mass redistributions have *** model calculated with parameters determined from the observation of tectonic tremors is quantitatively consistent with the slip during 1997-2013 inferred from GNss data,suggesting that the decrease in the sea-level change in approximately 2006 could cause the accele ration of a slip observed after *** result implies that the decreases in sea level in approximately 1996 and 2014 could also cause subsequent slip *** three slip acceleration periods temporally coincide with the increases in background seismicity in a shallower portion of the plate *** changes in seismicity are common to shallow earthquakes in the Tokai area,and a similar model can reproduce *** studies are expected to reveal causality between shallow earthquakes and long-term slip fluctuations based on modeling that considers changes in the frictional property along the plate interface.

关键词： Tides Ocean bottom pressure slow earthquake seismicity Kuroshio current

Preface to the special Issue on recent advances in the study of Equatorial Plasma Bubbles and Ionospheric scintillation

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Earth and Planetary Physics 2021年第5期5卷 365-367页

作者： yuichi Otsuka Luca spogli s.Tulasi Ram GuoZhu Li Institute for space-Earth Environmental Research Nagoya UniversityJapan Istituto Nazionale di Geofisicae Vulcanologia Italy Indian Institute of Geomagnetism India Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

The 2 nd Equatorial Plasma Bubble(EPB)workshop,funded by the Institute of Geology and Geophysics,Chinese Academy of sciences,and the National Natural science Foundation of China,took place in Beijing,China during september 13–15,*** EPB workshop belongs to a conference series that began in 2016 in Nagoya,Japan at the Institute for space-Earth Environmental Research,Nagoya University,resulting in a special issue of Progress in Earth and Planetary science that focused on *** main goal of the series is to organize in-depth discussion by scientists working on ionospheric irregularities,and solve the scientific challenges in EPB and ionospheric scintillation *** 2 nd EPB workshop gathered almost 60 scientists from seven countries.A total of 20 invited and contributing papers focusing on ionospheric irregularities and scintillations were *** we briefly comment on 10 papers included in this special issue.

关键词： equatorial plasma bubble ionospheric irregularity and scintillation plasma instability 2nd EPB workshop

Analytical study of performance evaluation for seismic retrofitting of reinforced concrete building using 3D dynamic nonlinear finite element analysis

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 291-302页

作者： yuichi sato shinichi Kajihara Yoshio Kaneko Department of Architecture and Architectural Engineering Kyoto University Technology Center Taisei Corporation

This paper presents three-dimensional finite element （FE） analyses of an all-frame model of a three-story reinforced concrete （RC） building damaged in the 1999 Taiwan Chi-Chi Earthquake. Non-structural brick walls of the building acted as a seismic resistant element although their contributions were neglected in the design. Hence, the entire structure of a typical frame was modeled and static and dynamic nonlinear analyses were conducted to evaluate the contributions of the brick walls. However, the results of the analyses were considerably overestimated due to coarse mesh discretizations, which were unavoidable due to limited computer resources. This study corrects the overestimations by modifying （1） the tensile strengths and （2） shear stiffness reduction factors of concrete and brick. The results indicate that brick walls improve frame strength although shear failures are caused in columns shortened by spandrel walls. Then, the effectiveness of three types of seismic retrofits is evaluated. The maximum drift of the first floor is reduced by 89.3%, 94.8%, and 27.5% by steel-confined, FuI1-RC, and Full-brick models, respectively. Finally, feasibility analyses of models with soils were conducted. The analyses indicated that the soils elongate the natural period of building models although no significant differences were observed.

关键词： reinforced concrete 1999 Taiwan Chi-Chi earthquake nonlinear finite element analysis seismic retrofit brick wall

star-Like Factors with Large Components

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Journal of the Operations Research society of China 2015年第1期3卷 81-88页

作者： Yao Zhang Gui-Ying Yan Mikio kano Academy of Mathematics and systems science Chinese Academy of SciencesBeijing 100190China Department of Computer and Information sciences Ibaraki UniversityHitachiIbaraki 316-8511Japan

A star-factor of a graph G is a spanning subgraph of G in which every component is a *** and saito(Discret Math 312:2005-2008,2012)showed that a graph G satisfying iso(G−s)≤|s|/m for every s⊂V(G)contains a{K1,t:m≤t≤2m}-factor,where iso(G−s)denotes the number of isolated vertices in G−*** they conjectured that a graph G satisfying iso(G−s)≤|s|/m for every s⊂V(G)actually contains a({K1,t:m≤t≤2m−1}∪{K2m+1})-*** this paper,we show that this conjecture is true.

关键词： star-factor Component Isolated vertex

QUADRANT ANALYsIs OF BUBBLE INDUCED VELOCITY FLUCTUATIONs IN A TRANsITIONAL BOUNDARY LAYER

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Journal of Hydrodynamics 2009年第1期21卷 93-99页

作者： HUANG Jian MURAI yuichi YAMAMOTO Fujio Graduate school of Engineering Fiber Amenity Engineering Course University of Fukui Bunkyo 3-9-1 Fukui 910-8507 Japan Division of Energy and Environment system School of Engineering Hokkaido University Sapporo Japan Graduate school of Engineering University of Fukui Bunkyo 3-9-1 Fukui 910-8507 Japan

Our previous study showed that the frictional drag decreases with increasing void fraction at Re〉1300, while it increases at Re 〈 1000. Decomposition of the Reynolds shear stress also implied that bubbles induce isotropy of turbulence. In order to confirm our previous analysis and to further investigate flow fields in the vicinity of bubbles, we analyze velocity fluctuations on the quadrant space in the streamwise and transverse directions （u′-v′ plane）. Here, we focus on two specific Reynolds numbers （at Re≈900 and ≈1410, which are close to the laminar-to-turbulent transition regime） and discuss bubble effects on sweep （u′〉 0, v′〈 0 ） and ejection （u′〈 0, v′〉 0） events as a function of the Reynolds number. We also illustrate velocity fluctuations in the vicinity of an individual bubble and a swarm of bubbles on the u′- v′ coordinates. The results show that a bubble swarm suppresses the velocity fluctuations at Re≈1410.

关键词： bubbly channel flow Particle Tracking Velocimetry (PTV) quadrant analysis velocity fluctuation boundary layer,laminar-to-turbulent transition

TEsTING k-EDGE-CONNECTIVITY OF DIGRAPHs

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Journal of systems science & Complexity 2010年第1期23卷 91-101页

作者： yuichi YOsHIDA.HiroI TO school of Informatics Kyoto University

This paper presents an algorithm that tests whether a given degree-bounded digraph is k-edge-connected or E-far from k-edge-connectivity. This is the first testing algorithm for k-edge- connectivity of digraphs whose running time is independent of the number of vertices and edges. A digraph of n vertices with degree bound d is ε-far from k-edge-connectivity if at least εdn edges have to be added or deleted to make the digraph k-edge-connected, preserving the degree bound. Given a constant error parameter ε and a degree bound d, our algorithm always accepts all k-edge-connected digraphs and reiects all digraphs that is ε-far from k-edge-connectivity with orobabilitv at least 2/*** runs in O（d（εd^-c）^k logεd^-1O）（c〉1 is a constant）time when input digraphs are restricted to be （k-1）-edge connected and runs in O（d（εd^-ck）^klogεd^-kO）（c〉1 is a constant）time for general digraphs.

关键词： Digraph graph k-edge-connectivity property testing.

Ensemble learning framework for landslide susceptibility mapping:Different basic classifier and ensemble strategy

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Geoscience Frontiers 2023年第6期14卷 170-190页

作者： Taorui Zeng Liyang Wu Dario Peduto Thomas Glade yuichi s.Hayakawa Kunlong Yin Institute of Geological survey China University of GeosciencesWuhan 430074China ENGAGE—Geomorphic systems and Risk Research Department of Geography and Regional ResearchUniversity of Vienna1010 ViennaAustria Faculty of Engineering China University of GeosciencesWuhanChina Department of Civil Engineering University of Salerno84084 SalernoFiscianoItaly Faculty of Environmental Earth science Hokkaido UniversityHokkaido 060-0810Japan

The application of ensemble learning models has been continuously improved in recent landslide susceptibility research,but most studies have no unified ensemble ***,few papers have discussed the applicability of the ensemble learning model in landslide susceptibility mapping at the township *** study aims at defining a robust ensemble framework that can become the benchmark method for future research dealing with the comparison of different ensemble *** this purpose,the present work focuses on three different basic classifiers:decision tree(DT),support vector machine(sVM),and multi-layer perceptron neural network model(MLPNN)and two homogeneous ensemble models such as random forest(RF)and extreme gradient boosting(XGBoost).The hierarchical construction of deep ensemble relied on two leading ensemble technologies(i.e.,homogeneous/heterogeneous model ensemble and bagging,boosting,stacking ensemble strategy)to provide a more accurate and effective spatial probability of landslide *** selected study area is Dazhou town,located in the Jurassic red-strata area in the Three Gorges Reservoir Area of China,which is a strategic economic area currently characterized by widespread landslide *** on a long-term field investigation,the inventory counting thirty-three slow-moving landslide polygons was *** results show that the ensemble models do not necessarily perform better;for instance,the Bagging based DT-sVM-MLPNNXGBoost model performed worse than the single XGBoost *** the eleven tested models,the stacking based RF-XGBoost model,which is a homogeneous model based on bagging,boosting,and stacking ensemble,showed the highest capability of predicting the landslide-affected ***,the factor behaviors of DT,sVM,MLPNN,RF and XGBoost models reflected the characteristics of slow-moving landslides in the Three Gorges reservoir area,wherein unfavorable lithological conditions and intense human engineering activitie

关键词： Three Gorges Reservoir Area Landslide susceptibility mapping Ensemble learning framework Uncertainty research

Multiplication formulas for Kubert functions

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Frontiers of Mathematics in China 2014年第1期9卷 101-109页

作者： Hailong LI Jing MA yuichi URAMATsU Department of Mathematics Weinan Teachers' University Weinan 714000 China school of Mathematics Jilin University Changchun 130012 China Graduate school of Advanced Technology Kinki University Iizuka Fukuoka 820-8555 Japan

The aim of this paper is two folds. First, we shall prove a general reduction theorem to the spannenintegral of products of （generalized） Kubert functions. second, we apply the special case of Carlitz＇s theorem to the elaboration of earlier results on the mean values of the product of Dirichlet L-functions at integer arguments. Carlitz＇s theorem is a generalization of a classical result of Nielsen in 1923. Regarding the reduction theorem, we shall unify both the results of Carlitz （for sums） and Mordell （for integrals）, both of which are generalizations of preceding results by Frasnel, Landau, Mikolas, and Romanoff et al. These not only generalize earlier results but also cover some recent results. For example, Beck＇s lamma is the same as Carlitz＇s result, while some results of Maier may be deduced from those of Romanoff. To this end, we shall consider the stiletjes integral which incorporates both sums and integrals. Now, we have an expansion of the sum of products of Bernoulli polynomials that we may apply it to elaborate on the results of afore-mentioned papers and can supplement them by related results.

关键词： Kubert function multiplication formula integral formula Bernoulli polynomial mean value