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Impulse Turbine with 3D Guide Vanes for Wave Energy Conversion

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Journal of Thermal Science 2006年第1期15卷 27-30页

作者： Manabu TAKAO Toshiaki SETOGUCHI Kenji KANEKO shuichi nagata Department of Mechanical Engineering Matsue National College of Technology 14-4 Nishiikuma-cho Matsue-shi Shimane 690-8518 Japan Department of Mechanical Engineering Saga University 1 Honjo-machi Saga-shi Saga 840-8502 Japan Institute of Ocean Energy Saga University 1 Honjo-machi Saga-shi Saga 840-8502 Japan

In this study, in order to achieve further improvement of the performance of an impulse turbine with fixed guide vanes for wave energy conversion, the effect of guide vane shape on the performance was investigated by experiment. The investigation was performed by model testing under steady flow condition. As a result, it was found that the efficiency of the turbine with 3D guide vanes are slightly superior to that of the turbine with 2D guide vanes because of the increase of torque by means of 3D guide vane, though pressure drop across the turbine for the 3D case is slightly higher than that for the 2D case.

关键词： fluid machinery impulse turbine guide vane wave energy conversion.

Edgeworth Approximation of a Finite Sample Distribution for an AR(1) Model with Measurement Error

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Open Journal of Statistics 2012年第4期2卷 383-388页

作者： shuichi nagata Department of Mathematical Sciences Kwansei Gakuin University Sanda Japan

In this paper, we consider the finite sample property of the ordinary least squares (OLS) estimator for an AR(1) model with measurement error. We present the Edgeworth approximation for a finite distribution of OLS up to O(T1/2). We introduce an instrumental variable estimator that is consistent in the presence of measurement error. Finally, a simulation study is conducted to assess the theoretical results and to compare the finite sample performances of these estimators.

关键词： Edgeworth Expansion OLS Measurement Error Instrumental Variables Estimator

Experimental Investigation on a Fixed Oscillating Water Column with an Impulse Turbine for Wave Energy Conversion

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Journal of Energy and Power Engineering 2020年第1期14卷 16-25页

作者： Tengen Murakami Yasutaka Imai shuichi nagata Manabu Takao Institute of Ocean Energy Saga University1HonjoSaga 840-8502Japan Department of Mechanical Engineering National Institute of TechnologyMatsue College14-4NishiikumaMatsueShimane 690-8518Japan

A fixed oscillating water column(OWC)-type wave energy converter consists of an air chamber,an air turbine and a *** energy conversion processes are the primary conversion in an air chamber and the secondary conversion of the *** the practical use,it is necessary to develop a design method which can consider the incident wave motion,the motion of the internal free surface affected in the structure such as a partly submerged wall,the fluctuation of air pressure in an air chamber,and the rotation of the air *** here,the authors carried out the wave tank tests using the model OWC equipped with the impulse turbine and a generator to obtain the experimental data needed to make this design *** the result,the efficiencies of the three cases with different speed ratio between generator and turbine,and the effects of the curtain wall depth and the wave length on the energy conversion performance were clarified.

关键词： Impulse turbine oscillating water column primary conversion secondary conversion wave energy

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直叶片动态效应水动力特性实验研究

可再生能源 2021年第1期39卷 137-142页

作者：王利东王龙陈兵永田修一村上天元大连理工大学海洋科学与技术学院辽宁盘锦124221 佐贺大学海洋能研究所佐贺县佐贺市8408502

文章通过水槽实验研究了直叶片在静态以及动态效应下的水动力特性。研究结果表明:在静态分析情况下,在来流加、减速过程中,直叶片的升、阻力系数的变化趋势相同;在动态分析情况下,当来流速度一定,电机转速不同时,直叶片的升、阻力系数... 详细信息

文章通过水槽实验研究了直叶片在静态以及动态效应下的水动力特性。研究结果表明:在静态分析情况下,在来流加、减速过程中,直叶片的升、阻力系数的变化趋势相同;在动态分析情况下,当来流速度一定,电机转速不同时,直叶片的升、阻力系数在不同转速下的变化趋势基本相同;当电机转速一定,来流速度不同时,来流速度对叶片水动力性能的影响具有一致性;与静态分析相比,翼型的动态失速角大于静态失速角,失速延迟现象较为明显。实验结果可为直叶片动态失速现象的研究提供一定的参考价值。

关键词：静态分析动态效应滞环现象水动力性能

Dataset for Beam Commissioning of the Vero4DRT System

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2016年第1期5卷 70-77页

作者： Hideharu Miura shuichi Ozawa Shintaro Tsuda Masahiro Hayata Kiyoshi Yamada Yasushi nagata Hiroshima High-Precision Radiotherapy Cancer Center Hiroshima Japan Department of Radiation Oncology Institute of Biomedical & Health Science Hiroshima University Hiroshima Japan

We present the results of measurements made using the Vero4DRT radiation therapy system, which is not yet widely used, to assist technicians in achieving reliable and safe radiotherapy to the patient. We measured percent depth dose, beam profile, and relative scatter factor under water and air conditions. The Vero4DRT system has a 150 × 150-mm fixed secondary collimator. Its multileaf collimator (MLC) design is a single-focus type, with 30 pairs of 5 mm thick leaves at the isocenter, and produces a maximum field size of 150 × 150 mm. Profile measurements were performed using a 0.016-cm3 ionization chamber (PTW31016 pinpoint chamber;PTW, Freiburg GmbH Germany). A brass build-up cap was used for measurements obtained in air conditions. We present a useful measurement dataset for users of the Vero4DRT system.

关键词： Vero4DRT Beam Characteristic Commissioning

Beam Characteristics at Low Dose Monitor Unit Settings for Vero4DRT

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2015年第4期4卷 284-289页

The stability of delivery of low monitor unit (MU) setting is important especially for step-and-shoot intensity-modulated radiotherapy (IMRT), because the nature of the technique is inherent to repeat beam on/off according to the number of the segments. This study evaluates the dose linearity and profile flatness/symmetry under low MU settings for Vero4DRT, a new linear-accelerator based irradiation system that currently implements step-and-shoot IMRT. To evaluate the dose linearity and flatness/symmetry, the point doses and beam profiles were measured as functions of MU and dose rates. The accuracy of dose delivery depended on the dose rate. Under all dose rates, the dose was linear within 1% above 5 MU and within 2% above 3 MU. The beam symmetry was degraded in-line compared with crossline, although both profiles were symmetric within 2% at all dose settings. The profile flatness was also within 2% above 5 MU at any dose rate and showed no significant variation among the low MU settings. To ensure stable beam delivery without increasing the treatment time of Vero4DRT, we recommend a delivery of 5 MU per segment at a dose rate of 500 MU/min.

关键词： Vero4DRT Step-and-Shoot IMRT Low Monitor Unit Beam Characteristic

Efficacy and safety of sofosbuvir and ledipasvir in Japanese patients aged 75 years or over with hepatitis C genotype 1

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World Journal of Hepatology 2017年第36期9卷 1340-1345页

作者： Yoshinori Ozono Kenji nagata Satoru Hasuike Hisayoshi Iwakiri Kenichi Nakamura Mai Tsuchimochi Yuri Yamada Yuka Takaishi Mitsue Sueta Tadashi Miike Yoshihiro Tahara Shojiro Yamamoto Kotaro Shide Tomonori Hidaka Yoko Kubuki Kazunori Kusumoto Toshimasa Ochiai Junya Kato Naoto Komada shuichi Hirono Kazuo Kuroki Masafumi Shigehira Kazuya Shimoda Department of Gastoroenterology and Hematology Faculty of Medicine University of Miyazaki Department of Liver Disease University of Miyazaki Hospital Department of Internal Medicine Koga General Hospital Department of Internal Medicine National Hospital Organization Miyakonojo Medical Center Department of Internal Medicine Hirono Naika Clinic Department of Internal Medicine Kushima Municipal Hospital Department of Internal Medicine Shigehira Clinic

AIM To evaluate the efficacy and safety of a regimen containing sofosbuvir(SOF) and ledipasvir(LDV) in Japanese patients aged ≥ 75 years with hepatitis C genotype *** This multicenter, retrospective study consisted of 246 Japanese patients with HCV genotype 1 at nine centers in Miyazaki prefecture in Japan. Demographic, clinical, virological, and adverse effects(AE)-related data obtained during and after SOF/LDV therapy were collected from medical records. These patients were divided into two groups, younger(aged < 75 years) and elderly(aged ≥ 75 years). Virological data and AEs were analyzed by age *** The sustained virological response(SVR) rates at 12 wk after treatment were 99.2%, 99.4%, and 98.7% in the overall population and in patients aged < 75 and ≥ 75 years, respectively. Common AEs during therapy were headache, pruritus, constipation, and insomnia. These occurred in fewer than 10% of patients, and their incidence was not significantly different between the younger and elderly groups. Two patients discontinued treatment, one due to a skin eruption and the other due to cerebral bleeding. CONCLUSION Compared with younger patients, elderly patients had a similar virological response and tolerance to SOF/LDV therapy.

关键词： Chronic hepatitis C Sofosbuvir Ledipasvir Sustained virological response Direct acting antivirals