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International Journal of Biomathematics 2012年第1期5卷 127-155页

作者： YUKIHIKO NAKATA yoichi ENATSU YOSHIAKI MUROYA Basque Center for Applied Mathematics Mazarredo 14 E-48009BilbaoSpain Department of Pure and Applied Mathematics Waseda University3-4-10hkubo Shinjuku-ku Tokyo169-8555Japan Department of Mathematics Waseda University 3-4-1 Ohkubo Shinjuku-ku Tokyo 169-8555Japan

We study global asymptotic stability for an SIS epidemic model with maturation delay proposed by K. Cooke, P. van den Driessche and X. Zou, Interaction of maturation delay and nonlinear birth in population and epidemic models, J. Math. Biol. 39（4）（1999） 332-352. It is assumed that the population has a nonlinear birth term and disease causes death of infective individuals. By using a monotone iterative method, we establish sufficient conditions for the global stability of an endemic equilibrium when it exists dependently on the monotone property of the birth rate function. Based on the analysis, we further study the model with two specific birth rate functions BI（N） = be-aN and B3（N） = A/N ＋ c, where N denotes the total population. For each model, we obtain the disease induced death rate which guarantees the global stability of the endemic equilibrium and this gives a positive answer for an open problem by X. Q. Zhao and X. Zou, Threshold dynamics in a delayed SIS epidemic model, J. Math. Anal. Appl. 257（2）（2001） 282-291.

关键词： SIS epidemic models nonlinear birth rate function disease induced deathrate global asymptotic stability the basic reproduction number permanence.

Effect of Rotational Speed on the Stability of Two Rotating Side-by-side Circular Cylinders at Low Reynolds Number

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Journal of Thermal Science 2018年第2期27卷 125-134页

作者： DOU Huashu ZHANG Shuo YANG Hui SETOGUCHI Toshiaki KINOUE yoichi Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech University Department of Mechanical Engineering Saga University

Flow around two rotating side-by-side circular cylinders of equal diameter D is numerically studied at the Rey- nolds number 40〈 Re 〈200 and various rotation rate 8i. The incoming flow is assumed to be two-dimensional laminar flow. The governing equations are the incompressible Navier-Stokes equations and solved by the finite volume method （FVM）. The ratio of the center-to-center spacing to the cylinder diameter is T/D=2. The objective of the present work is to investigate the effect of rotational speed and Reynolds number on the stability of the flow. The simulation results are compared with the experimental data and a good agreement is achieved. The stability of the flow is analyzed by using the energy gradient theory, which produces the energy gradient function K to identify the region where the flow is the most prone to be destabilized and the degree of the destabilization. Numerical results reveal that K is the most significant at the separated shear layers of the cylinder pair. With Re in- creases, the length of the wake is shorter and the vortex shedding generally exhibits a symmetrical distribution for θi〈θcrit. It is also shown that the unsteady vortex shedding can be suppressed by rotating the cylinders in the counter-rotating mode.

关键词： numerical simulation rotating circular cylinders stability vortex interactions energy gradient theory

Effects of hydraulic retention time on nitrification activities and population dynamics of a conventional activated sludge system

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Frontiers of Environmental Science & Engineering 2013年第1期7卷 43-48页

作者： Hongyan LI Yu ZHANG Min YANG yoichi KAMAGATA State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Research Institute of Genome-based Biofactory National Institute of Advanced Industrial Science and Technology Sapporo 062-8517 Japan

The effects of hydraulic retention time (HRT) on the nitrification activities and population dynamics of a conventional activated sludge system fed with synthetic inorganic wastewater were investigated over a period of 260 days. When the HRT was gradually decreased from 30 to 5 h, the specific ammonium-oxidizing rates (SAOR) varied between 0.32 and 0.45 kg (kg mixed liquor suspended solids (MLSS)·d) , and the specific nitrate-forming rates (SNFR) increased from 0.11 to 0.50 kg (kg MLSS·d) , showing that the decrease in HRT led to a significant increase in the nitrite oxidation activity. According to fluorescence in situ hybridization (FISH) analysis results, the proportion of ammonia-oxidizing bacteria (AOBs) among the total bacteria decreased from 33% to 15% with the decrease in HRT, whereas the fraction of nitrite-oxidizing bacteria (NOBs), particularly the fast-growing sp., increased significantly (from 4% to 15% for NOBs and from 1.5% to 10.6% for sp.) with the decrease in HRT, which was in accordance with the changes in SNFR. A short HRT favored the relative growth of NOBs, particularly the fast-growing sp., in the conventional activated sludge system.

关键词： ammonia-oxidizing bacteria hydraulic retention time nitrification activity nitrite-oxidizing bacteria population dynamics

Vortices within the Separation Region in a Decelerating Channel Flow (Effect of Inlet Velocity Gradient)

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Journal of Thermal Science 2005年第4期14卷 341-345页

作者： yoichi KINOUE Toshiaki SETOGUCHI Mohammad MAMUN Norimasa SHIOMI Kenji KANEKO Department of Mechanical Engineering Saga University1HonjoSaga840-8502Japan

An experimental investigation was made into three-dimensional separated flow and the vortices within the flow separation in a decelerating channel flow generated by the suction from a porous side wall. The flows along the side and bottom walls were visualized by the surface tuft method. The turbulent internal flow was measured by the split-film probe to investigate the turbulent flow including the reverse flow. In the flow visualization for the strong decelerating flow （the suction flow ratio：0.8）, two typical flow patterns appear alternatively. One is that the flow near the bottom wall separates more upstream than the flow near the top wall and a clockwise vortex can be seen in the separation region. Another is the reversal flow pattern with a counterclockwise vortex. By the turbulent flow measurement using the split-film probe, two peaks of turbulence level are observed for the strong decelerating flow case. These peaks can be related with two flow patterns mentioned above.

关键词： vortices within the separation decelerating channel flow turbulent flow split-film probe

Saturated hydraulic conductivity of compacted bentonite-sand mixtures before and after gas migration in artificial seawater

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第1期15卷 216-226页

作者： Yasutaka Watanabe Shingo Yokoyama Misato Shimbashi yoichi Yamamoto Takahiro Goto Sustainable System Research Laboratory Central Research Institute of Electric Power IndustryChibaJapan Science and Technology Department Nuclear Waste Management Organization of JapanTokyoJapan

To understand the self-healing property of an engineered barrier for radioactive waste disposal,the hydraulic conductivity of compacted bentoniteesand mixtures saturated with artificial seawater(SW)before and after gas migration was ***-and Ca-bentonites were mixed with fine sand at a ratio of 70%bentonite in dry *** aspects were considered during the experiment:the hydraulic conductivity of the specimen that was resaturated after gas migration and the distribution of water content immediately after gas migration to study gas migration *** gas migrated through the entire cross-section of the specimen,and gas breakthrough occurred in the equilibrium swelling pressure range ***,the gas flow rate reached a sufficient large value when the gas pressure was approximately twice the equilibrium axial pressure(the sum of swelling and confining pressures),which excluded the back *** the gas migration pathway was not visible when the specimen was observed immediately after gas migration,the water content distribution showed that several parts of the specimen with lower water content were connected in the direction of gas *** resaturation,the change in permeability was within a limited rangedtwo to three times larger than that before gas migration for each type of bentonite in *** slight change suggests that gas migration creates a pore structure that cannot be sealed via crystalline swelling of montmorillonite in SW,even if highly compacted bentonite is used under a constant-volume condition.

关键词： Bentonite Gas migration Hydraulic conductivity Seawater(SW) Self-healing

In the Mountain's Shadow: Japan's Silk Reelers Blazed an Asian Path of Economic Development

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Journal of Mountain Science 2004年第2期1卷 183-191页

作者： yoichi Shimatsu The founding faculty member of the Journalism and Media Studies Centre at The University of Hong Kong Lecturer in English-language news reporting at the School of Journalism and Communication at Tsinghua University in Beijing China

Exploring the history of the silk-reeling industry in Chichibu, Japan, this paper challenges the prevalent representation of mountain communities as marginal economic peripheries of the metropolitan center or as reservoirs of poverty and backwardness. Mountain districts were the cradle of an Asian 搃ndustrious?revolution that led to Japan抯 modernization. The highland-based silk-reeling producers pioneered an autonomous Asian model of industrial development, which competed successfully against the capital-intensive system introduced from the West into coastal cities. The export strength of silk-producing households in upland villages overturns the claim that Japan抯 economic miracle was based on the introduction of Western technology and administrative systems. To the contrary, the Asian-style management practices and labor standards developed by the silk producers were transferred to a succession of other industries. These indigenous practices account for the rise of Japanese industry in world markets. The clash between the two opposing models of modernization resulted in modern Japan抯 first major civil conflict, the Chichibu Rebellion of 1884, a legacy that has major implications for today抯 recession-mired Japan as well as for developing countries striving for an alternative path to economic development.

关键词： Mountain economics silk industry Japanese economic history Asian development

New approaches for archaeal genome-guided cultivation

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Science China Earth Sciences 2021年第10期64卷 1658-1673页

作者： Yinzhao WANG yoichi KAMAGATA Meng LI Feifei HAN Fengping WANG Xiang XIAO State Key Laboratory of Microbial Metabolism School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China Bioproduction Research Institute National Institute of Advanced Industrial Science and Technology(AIST)Tsukuba 310-8555Japan Shenzhen Key Laboratory of Marine Microbiome Engineering Institute for Advanced StudyShenzhen 518052China Department of Surgery Massachusetts General Hospital and Harvard Medical SchoolBoston MA 02114USA School of Oceanography Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Ocean Engineering Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Archaea,one of the three domains of life along with Bacteria and Eukarya,contains ancient life forms such as methanogen that are observed today on Earth,and one lineage Asgard archaea is also considered the closest ancestor of ***,with the development of interdisciplinary studies from Earth and Life sciences,archaeal organisms are considered to play pivotal roles in geochemical cycling in ***,our understanding of the attributes,origin and evolution,geochemical and ecological functions of Archaea is hampered by the scarcity of archaeal isolates,which has represented a challenge to researchers for the last 40 ***-independent sequencing and phylogenomic analyses have demonstrated a considerable diversity of Archaea with more than 20 novel ***,only four archaeal phyla have cultured representatives,leaving large gaps in our knowledge of the metabolic capabilities and ecological functions of the majority of archaeal strains identified exclusively by DNA *** this review,we summarize the discovery and development of archaeal research,highlight the knowledge gap between uncultured and cultured archaeal microbes,and call on the importance of devoting greater research efforts to archaeal ***,we outlined new ideas and strategic approaches,namely,(1)genome-based methods,(2)microbial network information-based methods,(3)genome-scale model-guided methods,and(4)machine learning methods,to enable the cultivation of uncultivated archaeal microbes using accumulated high-throughput sequencing data.

关键词： Archaea Cultivation Next-generation sequencing Uncultured archaea Genome Metabolic network

Does Property Right Transformation Improve Township and Village Enterprises Performance?

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China & World Economy 2006年第1期14卷 85-101页

作者： Zhixiong Du yoichi Izumida Professor Rural Development Institute Chinese Academy of Social Sciences Beijing China Professor Lab of Rural Finance Department of Agricultural and Resource Economics the University of Tokyo Tokyo Japan.

To date, few observations have been made about the performance improvement that resulted from the property right transformation of the collective-owned township and village enterprises （TVE） in the middle of 1990s. Using data collected from a questionnaire survey on the privatized TVE and their employees, the present paper provides some empirical evidence about this topic, and the analysis＇ suggests that property right transformation has had a positive impact on sample enterprises ＇performance, including business improvement, employment expansion, incremental investment and contributions to government revenues＇. The present study concludes that, from a transient viewpoint, the property right transformation has not distorted local governments＇ intentions to establish TVE in earlier years.

关键词： property right transformation township and village enterprises performance improvement

Three Dimensional Separation with Spiral-Focus in a Decelerating Duct Flow (Effect of Asymmetric Inlet Boundary Layer Thickness)

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Journal of Thermal Science 2003年第1期12卷 27-32页

作者： yoichi Kinoue Toshiaki Setoguchi Kenji Kaneko Mamun Mohammad Masahiro Inoue Department of Mechanical Engineering Saga University 1Department of Mechanical Engineering Saga University 1Department of Mechanical Engineering Saga University 1Department of Mechanical Engineering Saga University 1Department Honjo Saga 840-8502 Japan Honjo Saga 840-8502 Japan Honjo Saga 840-8502 Japan Honjo Saga 840-8502 Japanof Mechanical Engineering Science Kyushu University 6-10-1Hakozaki Higashi-ku Fukuoka 812-8581Japan

An experimental apparatus was developed to study the three dimensional separated flow with spiral-foci. The internal decelerating flow was generated by the air suction from a side wall to produce the separation on an opposite-side wall. The relation between the upstream boundary layer and the generation of spiral-foci in the separation region was observed by a tuft method. As a result, it was clarified that the spiral-focus type separation could be produced on the side wall and its behavior was closely related to the vortices supplied into the separation region from the boundary layer developing along top wall or bottom one.

关键词： three dimensional separation spiral-focus decelerating duct flow.

Flow Fields with Vortex in a Small Semi-open Axial Fan

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Journal of Thermal Science 2009年第4期18卷 294-300页

作者： Norimasa. Shiomi yoichi Kinoue Ying zi Jin Toshiaki Setoguchi Kenji Kaneko Department of Mechanical Engineering Saga University 1 Honjo-machi Saga 840-8502 Japan Institute of Mechatronics Zhejiang Sci-Tech University Xiasha Higher Educational Zone Hangzhou 310018 China

In order to clarify the effect of tip clearance （TC） size on fan performance and the flow field at rotor outlet in a small semi-open axial fan, the experimental investigation was carried out. The tip diameter of test fan rotor was 180mm and test TC sizes were lmm （TC=1mm） and 4mm （TC=4mm）. Fan characteristics tests were carried out for two cases of TC size and three-dimensional velocity fields at rotor outlet were measured using a single slant hot-wire probe at four flow-rate conditions. As a result, it was found that the pressure - flow-rate characteristics curves for two cases showed almost the same tendency. However, the ensemble averaged velocity profiles along radial measurement stations of TC-4mm largely changed compared with that of TC=1mm in cases of small flow-rate condition. From the phase-locked averaging results, it was also found that the vortex existed in the rotor outlet flow field of high flow-rate condition for each TC case. Compared with the vortices for TC=1mm and TC=4mm, the vortex for TC=4mm was stronger than that for TC=1mm.

关键词： fan semi-open type vortex tip clearance