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High-temperature corrosion of sintered RE_(2)Si_(2)O_(7)(RE=Yb and Ho)environmental barrier coating materials by volcanic ash

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1628-1638页

作者： Ayahisa Okawa Son Thanh Nguyen Tadachika Nakayama Thi-Mai-Dung Do Hisayuki Suematsu Shu Yin Takuya hasegawa Tsuneo Suzuki takashi Goto Koichi Niihara Institute of Multidisciplinary Research for Advanced Materials Tohoku UniversitySendai 980-8577Japan Department of Creative Engineering National Institute of TechnologyKushiro 084-0916Japan Extreme Energy-Density Research Institute Nagaoka University of TechnologyNagaoka 940-2188Japan Advanced Institute for Materials Research(WPI-AIMR) Tohoku UniversitySendai 980-8577Japan

Rare-earth silicates are promising environmental barrier coatings(EBCs)that can protect SiC_(f)/Si C_(m)substrates in next-genera tion gas turbine ***,RE_(2)Si_(2)O_(7)(RE=Yb and Ho)shows potential as an EBC due to its coefficient of thermal expansion(CTE)compatible with substrates and high resistance to water vapor *** target operating temperature for next-generation tur bine blades is 1400°*** is inevitable during adhesion to molten volcanic ash,and thus,understanding the corrosion behavior o the material is crucial to its *** study investigates the high-temperature corrosion behavior of sintered RE_(2)Si_(2)O_(7)(RE=Yb and Ho).Samples were prepared using a solid-state reaction and hot-press *** were then exposed to volcanic ash at 1400°C for 224,and 48 *** 48 h of exposure,volcanic ash did not react with Yb_(2)Si_(2)O_(7)but penetrated its interior,causing *** Ho_(2)Si_(2)O_(7)was partially dissolved in the molten volcanic ash,forming a reaction zone that prevented volcanic ash melts from penetrating the *** increasing heat treatment time,the reaction zone expanded,and the thickness of the acicular apatite grains increased The Ca:Si ratios in the residual volcanic ash were mostly unchanged for Yb_(2)Si_(2)O_(7)but decreased considerably over time for Ho_(2)Si_(2)O_(7).Th Ca in volcanic ash was consumed and formed apatite,indicating that RE^(3+)ions with large ionic radii(Ho>Yb)easily precipitated apatit from the volcanic ash.

关键词： environmental barrier coating volcanic ash rare-earth disilicate corrosion

Effects of Earth's curvature and radial heterogeneity in dislocation studies:Case studies of the 2008 Wenchuan earthquake and the 2004 Sumatra earthquake

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Earthquake Science 2010年第4期23卷 301-308页

作者： Guangyu Fu Wenke Sun Yoichi Fukuda Shanghua Gao takashi hasegawa Institute of Earthquake Science China Earthquake Administration Beijing 100036 China Department of Geophysics Graduate School of Science Kyoto University Kyoto 606-8502 Japan Laboratory of Computational Geoclynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China

Recently, effects of Earth＇s curvature and radial heterogeneity on coseismic deformations are often investi- gated based on the 2004 Sumatra earthquake. However, such effects are strongly related to earthquake types. As a low dip angle event, the 2004 Sumatra earthquake is not a good seismic case for such a topic since the effects for moderate dip angle events are much bigger. In this study, the half-space and spherical dislocation theories are used, respectively, to calculate co- seismic displacements caused by the 2008 Wenchuan earthquake and the 2004 Sumatra earthquake. Effects of Earth＇s curva- ture and stratification are investigated through the discrepancies of results calculated using the two dislocation theories. Re- sults show that the effects of Earth＇s curvature and stratification for the 2008 Wenchuan earthquake are much larger than those for the 2004 Sumatra earthquake. Ignoring the effects will cause errors up to 100%-200% in far field displacements for a moderate dip angle event like the 2008 Wenchuan earthquake. Such great effects are much bigger than those conclusions of previous studies. Besides, comparison with observations verifies that spherical dislocation theories yield better results than half-space ones in far fields.

关键词： coseismic displacement dislocation theory Earth model

Effects of Gaussian filter in processing GRACE data: Gravity rate of change at Lhasa,southern Tibet

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Science China Earth Sciences 2011年第9期54卷 1378-1385页

作者： SUN WenKe hasegawa takashi ZHANG XinLin FUKUDA Yoichi SHUM C. K. WANG Lei Key Laboratory of Computational Geodynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China Department of Geophysics Kyoto University Japan Earthquake Research Institute The University of Tokyo Japan Division of Geodetic Science School of Earth Sciences The Ohio State University OH 43210-1398 USA

In this paper, the spatial gravity distribution over Tibetan Plateau and the gravity rate of change at Lhasa for different Gaussian filter radii are computed using GRACE data. Results show that the estimate of the gravity rate of change is spatialradius-dependent of the Ganssian filter. The GRACE-estimated gravity rate of change agrees well with the surface measured one. In other words, the GRACE-estimated gravity rate of change has a limited value as that obtained by surface measurement when the spatial filter radius reaches zero. Then numerical simulations are made for different spatial radii of the Gaussian filter to investigate its behaviors when applied to surface signals. Results show that the estimate of a physical signal is filter-radius dependent. If the computing area is equal to or less than the mass area, especially for a uniformly distributed mass, the estimate gives an almost correct result, no matter what filter radius is used. The estimate has large error because of the signal leakage caused by harmonic truncation if the computing area is much bigger than the mass distribution （or inverse for a small mass anomaly）. If a mass anomaly is too small, it is difficult to recover it from space observation unless the filter radius is extremely small. If the computing point （or area） is outside the mass distribution, the estimated result is almost zero, particularly for small filter radii. These properties of the Gaussian filter are helpful in applying GRACE data in different geophysical problems with different spatial position and geometrical size. We further discuss physical sources causing the scalar gravity change at Lhasa. Discussions indicate that the gravity rate of change at Lhasa is not caused by the present-day ice melting （PDIM）（or Little Ice Age, LIA） effect because no ice melting occurs in Lhasa city and nearby. The gravity rate of change is attributable mainly to tectonic deformation associated with the Indian Plate collision. Simultaneous surf

关键词： gravity change GRACE Gaussian filter Tibetan Plateau Lhasa

Corticospinal excitability during motor imagery is diminished by continuous repetition-induced fatigue

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Neural Regeneration Research 2021年第6期16卷 1031-1036页

作者： Akira Nakashima Takefumi Moriuchi Daiki Matsuda takashi hasegawa Jirou Nakamura Kimika Anan Katsuya Satoh Tomotaka Suzuki Toshio Higashi Kenichi Sugawara Department of Rehabilitation Juzenkai HospitalNagasakiJapan Graduate School of Biomedical Sciences Nagasaki UniversityNagasakiJapan School of Rehabilitation Kanagawa University of Human ServicesYokosukaJapan

Application of continuous repetition of motor imagery can improve the performance of exercise ***,there is a lack of more detailed neurophysiological evidence to support the formulation of clear standards for interventions using motor ***,identification of motor imagery intervention time is necessary because it exhibits possible central ***,the purpose of this study was to elucidate the development of fatigue during continuous repetition of motor imagery through objective and subjective *** study involved two *** experiment 1,14 healthy young volunteers were required to imagine grasping and lifting a 1.5-L plastic bottle using the whole *** participant performed the motor imagery task 100 times under each condition with 48 hours interval between two conditions:500 mL or 1500 mL of water in the bottle during the demonstration *** fatigue and a decrease in pinch power appeared under the 1500-mL *** were changes in concentration ability or corticospinal excitability,as assessed by motor evoked potentials,between each set with continuous repetition of motor imagery also under the 1500-mL ***,in experiment 2,12 healthy volunteers were required to perform the motor imagery task 200 times under the 1500-mL *** concentration ability and corticospinal excitability *** is the first study to show that continuous repetition of motor imagery can decrease corticospinal excitability in addition to producing mental *** study was approved by the Institutional Ethics Committee at the Nagasaki University Graduate School of Biomedical and Health Sciences(approval No.18121302)on January 30,2019.

关键词： central nervous system concentration continuous repetition of motor imagery corticospinal excitability mental fatigue motor evoked potential motor imagery muscle fatigue neurophysiology transcranial magnetic stimulation

Assessment of cardiac output in liver transplantation recipients

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Hepatobiliary & Pancreatic Diseases International 2008年第4期7卷 362-366页

作者： Tomohide Hori Chiduru Yamamoto Shintaro Yagi Taku Iida Kentaro Taniguchi takashi hasegawa Koichiro Yamakado Yukinobu Hori Kan Takeda Kazuo Maruyama Shinji Uemoto Department of Hepato-Pancreato-Biliary Surgery and Transplantation Kyoto University Hospital54 Shogoinkawara- choSakyo-kuKyoto606-8507Japan Department of Hepatobiliary Pancreatic Surgery Mie University Hospital2-174 EdobashiTsu CityMie Prefecture514-8507 Japan Department of Anesthesiology and Critical Care Medicine Mie University Graduate School of Medicine2-174 EdobashiTsu CityMie Prefecture514-8507Japan Department of Radiology Mie University Graduate School of Medicine2-174 EdobashiTsu CityMie Prefecture514-8507Japan Nagoya Economic University Graduate School of Law 61-1 UchikuboInuyama City Aichi Prefecture 484-8504Japan

BACKGROUND:Liver cirrhosis causes peculiar systemic hemodynamics,and accurate evaluation of systemic hemodynamic state is important for cirrhotic recipients who underwent living donor liver transplantation(LDLT). We investigated the clinical advantages of a novel non- invasive method for measuring systemic hemodynamic parameters using indocyanine green(ICG). METHODS:Twenty-eight LDLT recipients were evaluated. Simultaneous measurements of cardiac output(CO)using Swan-Ganz catheters and pulse dye densitometry(PDD) were performed every 12 hours after LDLT.A total of 155 sets of simultaneous CO measurements were obtained. RESULTS:The CO values obtained by PDD correlated well with those obtained by the invasive catheter *** addition,none of the recipients developed any side-effects, and we verified the safety of repeated ICG *** is safe,even for repeated use over time in the same recipient. Moreover,PDD can measure the blood volume(BV).CONCLUSIONS:Since the cirrhotic systemic hemody- namics characterized by high CO and large BV remains, even after LDLT,the ability to measure CO and BV in a non-invasive,simple and real-time manner using PDD has advantages for cirrhotic LDLT recipients.

关键词： liver transplantation indocyanine green pulse dye densitometry blood volume cardiac output liver cirrhosis

Stability of cirrhotic systemic hemodynamics ensures sufficient splanchnic blood flow after living-donor liver transplantation in adult recipients with liver cirrhosis

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World Journal of Gastroenterology 2007年第44期13卷 5918-5925页

作者： Tomohide Hori Shintaro Yagi Taku Iida Kentaro Taniguchi Kentaro Yamagiwa Chiduru Yamamoto takashi hasegawa Koichiro Yamakado Takuma Kato Kanako Saito Linan Wang Mie Torii Yukinobu Hori Kan Takeda Kazuo Maruyama Shinji Uemoto Departments of Hepatobiliary Pancreatic Surgery Mie University Hospital 2-174 Edobashi Tsu City Mie Prefecture 514-8507 Japan Department of Cellular and Molecular Immunology Mie University Graduate School of Medicine 2-174 Edobashi Tsu City Mie Prefecture 514-8507 Japan Department of Hepatobiliary Pancreatic and Transplant Surgery Kyoto University Hospital 54 Kawahara-cho Shogoin Sakyo-ku Kyoto 606-8507 Japan Department of Anesthesiology and Critical Care Medicine Mie University Hospital 2-174 Edobashi Tsu City Mie Prefecture 514-8507 Japan Department of Radiology Mie University Hospital 2-174 Edobashi Tsu City Mie Prefecture 514-8507 Japan Department of Medical Oncology and Immunology Mie University Graduate School of Medicine 2-174 Edobashi Tsu City Mie Prefecture 514-8507 Japan Nagoya Economic University Graduate School of Law 61-1 Uchikubo Inuyama City Aichi Prefecture 484-8504 Japan

AIM： To investigate the correlation between systemic hemodynamics and splanchnic circulation in recipients with cirrhosis undergoing living-donor liver transplantation （LDLT）, and to clarify how systemic hemodynamics impact on local graft circulation after LDLT.METHODS： Systemic hemodynamics, indocyanine green （ICG） elimination rate （K,cG） and splanchnic circulation were simultaneously and non-invasively investigated by pulse dye densitometry （PDD） and ultrasound. Accurate estimators of optimal systemic hyperdynamics after LDLT [i.e., balance of cardiac output （CO） to blood volume （BV） and mean transit time （MTT）, defined as the time required for half the administered ICG to pass through an attached PDD sensor in the first circulation] were also measured. Thirty recipients with cirrhosis were divided into two groups based on clinical outcomes corresponding to postoperative graft function.RESULTS： Cirrhotic systemic hyperdynamics characterized by high CO, expanded BV and low total peripheral resistance （TPR） were observed before LDLT. TPR reflecting cirrhotic vascular alterations was slowly restored after LDLT in both groups. Although no significant temporal differences in TPR were detected between the two groups, CO/BV and M＇IT differed significantly. Recipients with good outcomes showed persistent cirrhotic systemic hyperdynamics after LDLT, whereas recipients with poor outcomes presented with unstable cirrhotic systemic hyperdynamics and severely decreased KICG. Systemic hyperdynamic disorders after LDLT impacted on portal venous flow but not hepatic arterial flow.CONCLUSION： We conclude that subtle systemic hyperdynamics disorders impact on splanchnic circulation, and that an imbalance between CO and BV decreases portal venous flow, which results in critical outcomes.

关键词： Cirrhosis Hyperdynamic Portal hypertension Splanchnic Indocyanine green

Causal relationships between physical, mental and social health-related factors among the Japanese elderly: A chronological study

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Health 2012年第3期4卷 133-142页

作者： Motoyuki Yuasa Tanji Hoshi takashi hasegawa Naoko Nakayama Toshihiko Takahashi Sugako Kurimori Naoko Sakurai Graduate School of Medicine Juntendo University Tokyo Japan Graduate School of Nursing Ibaraki Christian University Ibaraki Japan Graduate School of Nursing Keio University Kanagawa Japan Graduate School of Urban System Science Tokyo Metropolitan University Tokyo Japan School of Nursing Tokyo Jikeikai Medical College Tokyo Japan

The World Health Organization defines health as a state of physical, mental and social well being. This study was conducted to explore chronological relationships between physical, mental and social factors. Among urban-dwelling elderly aged 65 years and over, data were collected via a self-report questionnaire in 2001 and 2004. The three health-related latent factors were identified with nine measurement variables by an exploratory factor analysis. A structural equation modeling method was used to analyze underlying relationships among the three factors with a cross-lagged model and a synchronous model. A total of 7,683 individuals aged between 65 and 84 years were analyzed. The three-year prior and current physical health significantly affected social health as well as mental health, and this effect appeared to be stronger in males compared to females. Maintenance of physical health may be crucial to support mental and social health among elderly individuals.

关键词： Physical Health Mental Health Social Health Elderly Japan

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深圳市黄木岗交通枢纽中国深圳市福田区

世界建筑导报 2023年第S2期38卷 22-25页

作者：横尾茂长谷川隆刘超无不详中国铁路设计集团有限公司深圳市建筑设计研究总院有限公司深圳市城市交通规划设计有限公司中国城市规划设计研究院

以车站的升级改造为契机重塑城市黄木岗交通枢纽位于深圳市福田中心西北方向3.5公里处,现有地铁7号线和14号线,承担着周边居民上下班和上下学交通功能的同时,还具有通往深圳市第二人民医院和深圳市体育中心的功能。根据深圳市的地铁线... 详细信息

以车站的升级改造为契机重塑城市黄木岗交通枢纽位于深圳市福田中心西北方向3.5公里处,现有地铁7号线和14号线,承担着周边居民上下班和上下学交通功能的同时,还具有通往深圳市第二人民医院和深圳市体育中心的功能。根据深圳市的地铁线路规划,贯穿东西的24号线将延长至此,届时该站将成为3条地铁线的换乘枢纽站,这将大大提高该地区前往福田中心城区的可达性,从而提升周边地区的土地价值。车站空间不仅需要与之相匹配的品质和规模,周边城市更新的必要性也愈加迫切,这要求该项目能够使车站和街区在彼此的积极影响下共同发展,使整个地区实现高品质的功能更新。

关键词：交通枢纽深圳市福田区功能更新体育中心地铁线路可达性西北方向上下学交通

长持时地震作用下钢结构梁柱节点塑性变形能力

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建筑结构 2015年第11期45卷 1-8页

作者：山田哲焦瑜成原弘之安田聡長谷川隆东京工业大学结构工程研究中心东京理科大学工学院大成建设株式会社技术中心日本建筑研究院

延性破坏是钢框架中梁柱节点最常见的破坏模式之一。目前主要通过试验方法来评价发生延性破坏钢梁的塑性变形能力,其中材料的屈强比、梁的弯矩梯度和梁柱节点的详细构造等都是重要的参数。但是在实际试验中要涵盖所有这些参数是不可能的... 详细信息

延性破坏是钢框架中梁柱节点最常见的破坏模式之一。目前主要通过试验方法来评价发生延性破坏钢梁的塑性变形能力,其中材料的屈强比、梁的弯矩梯度和梁柱节点的详细构造等都是重要的参数。但是在实际试验中要涵盖所有这些参数是不可能的,也是不现实的。此外,影响钢梁塑性变形能力的另一个重要的因素是加载机制。最近几年,长持时地震对结构构件的影响备受关注。长持时地震作用下,钢梁往往承受长时间的低幅循环荷载,然而,目前的试验研究中大多采用各个国家规范推荐的振幅递增加载机制。通过数值分析方法,对长持时地面运动作用下钢梁的塑性变形能力进行评估。

关键词：梁柱节点延性断裂平面内数值分析循环荷载试验塑性变形能力长持时地震作用