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Numerical analysis of cavitation cloud shedding in a submerged water jet

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Journal of Hydrodynamics 2016年第6期28卷 986-993页

作者： Guoyi PENG 杨从新 Yasuyuki OGUMA seiji shimizu Department of Mechanical Engineering College of Engineering Nihon University School of Energy and Power Engineering Lanzhou University of Technology

Focused on the unsteady behavior of high-speed water jets with intensive cavitation a numerical analysis is performed by applying a practical compressible mixture flow bubble cavitation model with a simplified estimation of bubble radius. The mean flow of two-phase mixture is calculated by unsteady Reynolds averaged Navier-Stokes （URANS） for compressible flow and the intensity of cavitation in a local field is evaluated by the volume fraction of gas bubbles whose radius is estimated with a simplified Rayleigh- Plesset equation according to pressure variation of the mean flow field. High-speed submerged water jet issuing from a sheathed sharp-edge orifice nozzle is treated. The periodically shedding of cavitation clouds is captured in a certain reliability compared to experiment data of visualization observation and the capability to capture the unsteadily shedding of cavitation clouds is demonstrated. The results demonstrate that cavitation takes place near the entrance of nozzle throat and cavitation cloud expands consequentially while flowing downstream. Developed bubble clouds break up near the nozzle exit and shed downstream periodically along the shear layer. Under the effect of cavitation bubbles the decay of core velocity is delayed compared to the case of no-cavitation jet.

关键词： cavitation bubble dynamics submerged water jet two-phase flow turbulent flow

Periodic Behavior of Cavitation Cloud Shedding in Submerged Water Jets Issuing from a Sheathed Pipe Nozzle

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Journal of Flow Control, Measurement & Visualization 2018年第1期6卷 15-26页

作者： Guoyi Peng Ayaka Wakui Yasuyuki Oguma seiji shimizu Hong Ji Department of Mechanical Engineering College of Engineering Nihon University Koriyama Japan Graduate School of Engineering Nihon University Koriyama Japan College of Energy and Power Engineering Lanzhou University of Technology Lanzhou China

The behavior of cavitation cloud shedding in submerged water jets issuing from a sheathed pipe nozzle is investigated experimentally by high-speed camera visualization observation. Experiments are carried out under different cavitation numbers decreased to 0.01 with increase of the injection pressure, and the frequency spectrum of cavitation cloud shedding is evaluated by statistical analysis of a sequence of high-speed camera images. Experiments demonstrate that cavitation clouds appear when the cavitation number σ decreases to the level of 0.5-0.7 and developed cavitation clouds shed downstream periodically at multiple frequencies. The low frequency components of cavitation cloud shedding is basically dependent upon the pressure pulsation of plunger pump, which is often employed in various industry application of water jets. However, the high frequency components are closely related to the shedding of vortexes and the collapsing of cavitation clouds, which are dependent on the flow structure of submerged jets and the property of cavitation clouds consisted of numerous bubbles.

关键词： Water Jet Cavitation Cavitation Cloud Visualization Image Analysis

Design and construction of the cooperation support agent for face-to-face class and e-learning

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通讯和计算机（中英文版） 2009年第12期6卷 28-32页

作者： Misako Urakami Masaaki Kunishige seiji shimizu Yasukuni Okataku Nobukazu Yoshioka Oshima National College of Maritime Technology Yamaguchi 742-2193 Japan Chugoku Bureau of Telecommunications Ministry of Internal Affairs and Communications Naka-ku. Hiroshima 730-8795 Japan National Institute of lnformatics Tokyo 101-8430 Japan

Disruption of neuronal actin barrier promotes the entry of disease-implicated proteins to exacerbate amyotrophic lateral sclerosis pathology

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Neural Regeneration Research 2025年第9期20卷 2589-2590页

作者： Mikio shimizu Tatsusada Okuno Department of Neurology Osaka University Graduate School of MedicineSuitaJapan Department of Neurology Osaka General Medical CenterOsakaJapan

Amyotrophic lateral sclerosis(ALS)is a devastating neurological disease characterized by the accumulation of aberrant proteins in motor neurons of the brain and spinal *** with ALS develop skeletal muscle weakness,resulting in death from respiratory paralysis,which usually occurs 2-4 years after clinical onset(Goutman et al.,2022).

关键词： paralysis sclerosis

Neoadjuvant chemotherapy followed by surgery in gastric cancer patients with extensive lymph node metastasis

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World Journal of Clinical Oncology 2015年第6期6卷 291-294页

作者： seiji Ito Yuichi Ito Kazunari Misawa Yasuhiro shimizu Taira Kinoshita Department of Gastroenterological Surgery Aichi Cancer Center Hospital

Gastric cancer with extensive lymph node metastasis(ELM) is usually considered unresectable and is associated with poor outcomes. Cases with clinical enlargement of the para-aortic lymph nodes and/or bulky lymph node enlargement around the celiac artery and its branches are generally dealt with as ELM. A standard treatment for gastric cancer with ELM has yet to be determined. Two phase Ⅱ studies of neoadjuvant chemotherapy followed by surgery showed that neoadjuvant chemotherapy with S-1 plus cisplatin followed by surgical resection with extended lymph node dissection could represent a treatment option for gastric cancer with ELM. However,many clinical questions remain unresolved,including the criteria for diagnosing ELM,optimal regime,number of courses and extent of lymph node dissection.

关键词： Extended lymph node metastasis Gastric cancer Neoadjuvant chemotherapy Gastrectomy Lymph node dissection

FE FORMULATION FOR THE VISCOELASTIC BODY MODELED BY FRACTIONAL CONSTITUTIVE LAW

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Acta Mechanica Sinica 2001年第4期17卷 354-365页

作者：张卫 Nobuyuki shimizu Institute of Applied Mechanics Jinan UniversityGuangzhou 510632China Department of Mechanical Engineering Iwaki Meisei UniversityJapan

This paper presents finite element (FE) formulation of the viscoelastic materials described by fractional constitutive law. The time-domain three-dimensional constitutive equation is constructed. The FE equations are set up by treating the fractional operator as a special case of the hereditary integration. The equations are solved by numerical integration method. The numerical algorithm developed by the authors for Liouville-Riemann's fractional derivative was adopted to formulate FE procedures and extended to solve the more general case of the hereditary integration. The numerical examples were given to show the correctness and effectiveness of the integration algorithm.

关键词： viscoelasticity fractional calculus FEM polymer materials

Image of Ne Trap by a Microwave Cavity

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Chinese Physics Letters 1997年第2期14卷 93-95页

作者： XU Lei Satoshi Oishi Kazuko shimizu Hiroshi Takuma Fujio shimizu Department of Physics Fudan UniversityShanghai 200433 Institute for Laser Science The University of Electro-communicationsChofugaokaChofushiTokyo 182Japan Department of Applied Physics University of TokyoBunkyo-kuTokyo 113Japan

The focusing of Ne metastable atoms trapped in magnetic-optical trap by a microwave cavity was *** cavity was operated at TM010 *** a microwave power of 14W,the Ne trap was imaged to a spot of about 0.25mm(full width ... 详细信息

关键词： microwave Microwave cavity

Gut microbiota in common elderly diseases affecting activities of daily living

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World Journal of Gastroenterology 2018年第42期24卷 4750-4758页

作者： Yukihiro shimizu Gastroenterology center Nanto Municipal Hospital

Gut microbiota are involved in the development or prevention of various diseases such as type 2 diabetes,fatty liver, and malignancy such as colorectal cancer,breast cancer and hepatocellular carcinoma. Alzheimer'sdisease, osteoporosis, sarcopenia, atherosclerotic stroke and cardiovascular disease are major diseases associated with decreased activities of daily living(ADL), especially in elderly people. Recent analyses have revealed the importance of gut microbiota in the control of these diseases. The composition or diversity of these microbiota is different between patients with these conditions and healthy controls, and administration of probiotics or prebiotics has been shown effective in the treatment of these diseases. Gut microbiota may affect distant organs through mechanisms that include regulating the absorption of nutrients and/or the production of microbial metabolites, regulating and interacting with the systemic immune system, and translocating bacteria/bacterial products through disrupted mucosal ***, the gut microbiota may be important regulators in the development of diseases that affect ADL. Although adequate exercise and proper diet are important for preventing these diseases, their combination with interventions that manipulate the composition and/or diversity of gut microbiota could be a promising strategy for maintaining health condition and preserving ADL. This review thus summarizes current understanding of the role of gut microbiota in the development or prevention of diseases closely associated with the maintenance of ADL.

关键词： Probiotics Prebiotics Alzheimer’s disease Osteoporosis Sarcopenia Gut microbiota Cardiovascular disease Cerebrovascular disease

Laser Interference Lithography for Fabrication of Planar Scale Gratings for Optical Metrology

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Nanomanufacturing and Metrology 2021年第1期4卷 3-27页

作者： Yuki shimizu Department of Finemechanics Tohoku University6-6-01Aramaki Aza-AobaAoba-kuSendaiMiyagi 980-8579Japan

Laser interference lithography is an attractive method for the fabrication of a large-area two-dimensional planar scale grating,which can be employed as a scale for multi-axis optical encoders or a diffractive optical element in many types of optical ***,optical configurations such as Lloyd's mirror interferometer based on the division of wavefront method can generate interference fringe fields for the patterning of grating pattern structures at a single exposure in a stable *** the fabrication of a two-dimensional scale grating to be used in a planar/surface encoder,an orthogonal two-axis Lloyd's mirror interferometer,which has been realized through innovation to Lloyd’s mirror interferometer,has been *** addition,the concept of the patterning of the two-dimensional orthogonal pattern structure at a single exposure has been extended to the non-orthogonal two-axis Lloyd’s mirror ***,the optical setup for the non-orthogonal two-axis Lloyd's mirror interferometer has been optimized for the fabrication of a large-area scale *** this review article,principles of generating interference fringe fields for the fabrication of a scale grating based on the interference lithography are reviewed,while focusing on the fabrication of a two-dimensional scale grating for planar/surface *** of the pitch of the fabricated pattern structures,whose accuracy strongly affects the performance of planar/surface encoders,is also an important task to be *** this paper,major methods for the evaluation of a grating pitch are also reviewed.

关键词： Planar scale grating Interference lithography Lloyd’s mirror interferometer Interference fringe