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Effect of bent inlet pipe on the flow instability behavior of centrifugal compressors

Chinese Journal of Aeronautics 2020年第8期33卷 2099-2109页

作者： Zhenzhong SUN Baotong WANG Xinqian ZHENG tomoki kawakubo Hideaki TAMAKI Ryuusuke NUMAKURA Department of Aerodynamics and Thermodynamics Institute for Aero EngineTsinghua UniversityBeijing 100084China Corporate Research&Development IHI CorporationYokohama 235-8501Japan State Key Laboratory of Automotive Safety and Energy School of Vehicle and MobilityTsinghua UniversityBeijing 100084China

Bent inlet pipes are often used in centrifugal compressors due to limited installation space,and an understanding of the effect on compressor stability is essential for safety and *** paper firstly investigates flow instability behaviors in two compressors,one with a straight inlet pipe and the other with an S-shaped bent *** detail,it analyzes the resulting flow fields,instability evolution paths and surge *** results show that the S-shaped pipe obviously affects the flow field at high mass flow rates,while reverse flow mainly influences the flow field at low mass flow *** flow first occurs at certain flow passages with a high pressure difference that is predominantly decided by the volute rather than the S-shaped bent *** addition,centrifugal compressors can tolerate reverse flow to some extent so that surge would not occur immediately if reverse flow occurs unless the reverse flow region extends circumferentially and radially to a sufficiently large *** the S-shaped pipe is not dominant in the creation and extension of reverse flow,it does not exacerbate the stability of the central compressor to a great *** but not least,the S-shaped pipe is noted to delay the occurrence of surge at 90%rotating speed,which suggests the possibility of improving compressor stability with bent inlet *** result differs from the conventional understanding that inlet distortion usually deteriorates compressor stability and emphasizes the particularity of centrifugal compressors.

关键词： Bent pipe Centrifugal compressor Flow field Flow instability Surge boundary

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A novel experimental method to evaluate the impact of volute's asymmetry on the performance of a high pressure ratio turbocharger compressor

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Science China(Technological Sciences) 2012年第6期55卷 1695-1700页

作者： LIN Yun ZHENG XinQian JIN Lei TAMAKI Hideaki kawakubo tomoki State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China IHI Corporation TokyoJapan

All components of a turbocharger compressor are axisymmetric except for the spiral-shaped,gas-collecting overhung *** this paper,a novel experimental method to evaluate the impact of the volute's asymmetry on centrifugal compressor performance is proposed and applied to a high pressure-ratio turbocharger *** method can isolate the impact of the volute's asymmetry on the compressor performance for the first *** prove the considerable impact of the volute's asymmetry on the compressor performance,especially the stability and *** impact of the volute's asymmetry on compressor stability correlates with rotational speed and thus with the pressure ratio,constricting the stable flow range by up to 47 percent and decreasing the maximum efficiency by 4.8 percent at the design *** results provide evidence to exploit the potential of intrinsic non-axisymmetric flow induced by asymmetric volute to improve the performance of turbocharger compressor with a high pressure ratio.

关键词： high pressure-ratio turbocharger centrifugal compressor volute IC engine

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径流涡轮叶片气动激振机制研究

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工程热物理学报 2022年第6期43卷 1503-1511页

作者：潘镭杨名洋 MURAE Shouta SATO Wataru kawakubo tomoki YAMAGATA Akihiro 邓康耀上海交通大学机械与动力工程学院上海200240 Turbomachinery G IHI CorporationYokohama 235-8501

径流涡轮叶片的高周疲劳问题严重威胁涡轮增压器的安全运行。学术界针对有叶涡轮的高周疲劳问题开展了广泛研究,但针对无叶涡轮高周疲劳的研究极少。本文采用单向流固耦合数值方法并结合实验测量,研究无叶涡轮叶片的气动激振机制。结果... 详细信息

径流涡轮叶片的高周疲劳问题严重威胁涡轮增压器的安全运行。学术界针对有叶涡轮的高周疲劳问题开展了广泛研究,但针对无叶涡轮高周疲劳的研究极少。本文采用单向流固耦合数值方法并结合实验测量,研究无叶涡轮叶片的气动激振机制。结果表明,叶片振幅与涡轮负荷成非单调关系,此现象在公开文献中未提及。能量分析表明,叶片吸力面能量的变化趋势是导致振幅与涡轮负荷成非单调关系的直接原因。流场分析进一步表明,叶片吸力面能量变化是由两种涡结构在不同负荷下的相互作用所引起的:叶片前缘的分离涡和叶尖间隙泄漏涡。本研究为设计高可靠性的无叶涡轮提供了理论指导。

关键词：涡轮增压器径流涡轮气动激振叶片振动

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有机工质真实气体的完全气体近似模型及其在径向进气涡轮气动模拟中应用（英文）

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风机技术 2018年第6期60卷 45-52页

作者： tomoki kawakubo Satoshi Ohuchida Turbomachinery and Engine Technology Dept. Product Development Center IHI CorporationShin-Nakahara-cho

Today the Organic Rankine Cycle(ORC) is considered as one of the most promising technologies to recover the power from low-grade heat resources. In order to realize a high performance ORC turbine, the Computational Fluid Dynamics(CFD) is extensively used to simulate the internal flow in the aerodynamic design. But due to the high non-ideality of the working fluid, it is crucial to take the real gas effect into *** the present study, an accurate and reliable method of the perfect gas approximation for an organic working fluid(R245 fa) is developed. At first, the effectiveness of a perfect gas approximation is examined in two-dimensional CFD simulations of a convergent-divergent nozzle. Then the accuracy of the perfect gas approximation, definition of suitable nondimensional performance parameters and effective conversion method between the different gas models are studied in three-dimensional CFD simulations of an ORC radial-inflow turbine.

关键词： Organic Rankine Cycle (ORC) Radial-inflow Turbine Organic Working Fluid Real Gas Effect Perfect Gas Approximation

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Current status and challenges in sentinel node navigation surgery for early gastric cancer

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Chinese Journal of Cancer Research 2021年第2期33卷 150-158页

作者： Satoru Matsuda Tomoyuki Irino Hirofumi kawakubo Hiroya Takeuchi Yuko Kitagawa Department of Surgery Keio University School of MedicineTokyo 160-8582Japan Department of Surgery Hamamatsu University School of MedicineShizuoka 431-3192Japan

As an optimal surgical procedure to accurately evaluate lymph node(LN)metastasis during surgery with minimal surgical resection,we have been developing sentinel node(SN)biopsy for early gastric cancer since the *** institutions from the Japanese Society of Sentinel Node Navigation Surgery(SNNS),including Keio University Hospital,conducted a multicenter prospective trial to validate the SN concept using the dual-tracer method with blue dye and a *** to the results,397 patients were included in the final analysis,and the overall accuracy in detecting LN metastasis using SN biopsy was 99%(383 of 387).Based on the validation study,we are targeting cT1N0 with a primary tumor of≤4 cm in diameter as an indication for SN biopsy for gastric *** are currently running a multicenter nonrandomized phaseⅢtrial to assess the safety and efficacy of SN navigation *** Korean group has reported the result of a multicenter randomized phaseⅢ*** meticulous gastric cancer in the remnant stomach was rescued by subsequent gastrectomy,the disease-specific survival was comparable between the two techniques,implying that SN navigation surgery can be an alternative to standard *** the development of SN biopsy procedure and treatment modalities,the application of SN biopsy will be expanded to achieve an individualized minimally invasive surgery.

关键词： Sentinel node gastric cancer minimally invasive surgery

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Nationwide questionnaire survey on pediatric pancreatic tumors in Japan

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World Journal of Gastrointestinal Oncology 2024年第10期16卷 4166-4176页

作者： Satoshi Makita Hiroo Uchida Motohiro Kano Naonori kawakubo Hiromu Miyake Akihiro Yoneda Tatsuro Tajiri Koji Fukumoto Department of Pediatric Surgery Nagoya University Graduate School of MedicineNagoya 466-8550Japan Department of Pediatric Surgery National Center for Child Health and DevelopmentTokyo 157-8535Japan Department of Pediatric Surgery Reproductive and Developmental MedicineFaculty of Medical SciencesKyushu UniversityFukuoka 819-0395Japan Department of Pediatric Surgery Shizuoka Children’s HospitalShizuoka 420-8660Japan

BACKGROUND Pediatric pancreatic tumors are rare and account for<0.1%of all childhood *** primary treatment for pancreatic tumors is surgical ***,because of the lack of knowledge regarding pediatric pancreatic tumors,no comprehensive treatment plans for pediatric pancreatic tumors have been *** To compared the clinical features,treatment methods,and prognosis of pediatric pancreatic tumors in Japan with those in other *** Questionnaires were sent to 213 pediatric surgical units in *** tumors that were not surgically treated were excluded from the *** primary survey investigated the number of patients aged 0-18 years who underwent pancreatic tumor surgery and the type of tumors managed during the 22-year study period(from January 1,2000 to December 31,2021)by post *** secondary survey assessed the clinical images,treatment methods,and tumor outcomes via *** The primary survey enrolled 228 *** the secondary survey,213 patients were eventually *** most common type of pancreatic tumor was solid pseudopapillary neoplasm(SPN)[n=164(77.0%)],followed by pancreatoblastoma[n=16(7.5%)],pancreatic endocrine tumor[n=14(6.6%)],non-epithelial tumor[n=9(4.2%)],pancreatic tumor[n=7(3.3%)],and metastatic pancreatic tumor[n=3(1.4%)].Overall,123(57.7%)patients underwent distal pancreatectomy,of whom 49 underwent laparoscopic ***-four(20.7%)patients underwent enucleation,of whom eight underwent laparoscopic ***-two(15.0%)patients underwent pancreaticoduodenectomy,of whom one underwent laparoscopic *** patients with SPN,including those with distant metastases and recurrent disease,*** SPN was more common in Japan than in other *** of the histological type,resection is the most effective treatment for pediatric pancreatic tumors.

关键词： Pancreatic tumors Pediatric Nationwide survey Solid pseudopapillary tumors Pancreatoblastoma

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Helicobacter heilmannii sensu stricto-related gastric ulcers:A case report

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World Journal of Gastroenterology 2014年第12期20卷 3376-3382页

作者： Takehisa Matsumoto Masatomo kawakubo Taiji Akamatsu Naohiko Koide Naoko Ogiwara Seiko Kubota Mitsutoshi Sugano Yoshiyuki Kawakami Tsutomu Katsuyama Hiroyoshi Ota Departments of Laboratory Medicine Shinshu University Hospital Endoscopy Center Suzaka HospitalNagano Prefectural Hospital Organization Department of Surgery Nagano Prefectural Kiso Hospital Department of Health and Medical Sciences Shinshu University Graduate School of Medicine Maruko Central Hospital

A spiral bacterium (SH9), morphologically different from Helicobacter pylori (H. pylori), was found in a 62-year-old woman’s gastric mucosa. Gastroscopic examination revealed multiple gastric ulcers near the pyloric ring; mapping gastric biopsy showed mild mononuclear infiltration with large lymphoid follicles in the antrum, without corpus atrophy. Urea breath test and H. pylori culture were negative, but Giemsa staining of biopsies revealed tightly coiled bacteria that immunostained with anti-H. pylori antibody. Sequencing of SH9 16S rRNA and the partial urease A and B subunit genes showed that the former sequence had highest similarity (99%; 1302/1315 bp) to Helicobacter heilmannii (H. heilmannii) sensu stricto (H. heilmannii s.s.) BC1 obtained from a bobcat, while the latter sequence confirmed highest similarity (98.3%; 1467/1493 bp) to H. heilmannii s.s. HU2 obtained from a human. The patient was diagnosed with multiple gastric ulcers associated with H. heilmannii s.s. infection. After triple therapy (amoxicillin, clarithromycin, and lansoprazole) with regimen for eradicating H. pylori, gastroscopy showed ulcer improvement and no H. heilmannii s.s. upon biopsy.

关键词： Helicobacter heilmannii sensu stricto, “ Helicobacter heilmannii” type 2, Gastric ulcers, Urease gene, Non-Helicobacter pylori helicobacters

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Recent advances in endoscopic ultrasonography-guided biliary interventions

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World Journal of Gastroenterology 2015年第32期21卷 9494-9502页

作者： Kazumichi kawakubo Hiroshi Kawakami Masaki Kuwatani Shin Haba Shuhei Kawahata Yoko Abe Yoshimasa Kubota Kimitoshi Kubo Hiroyuki Isayama Naoya Sakamoto Department of Gastroenterology and Hepatology Hokkaido University Graduate School of Medicine Department of Gastroenterology Graduate School of Medicine The University of Tokyo

Interventional endoscopic ultrasonography(EUS) based on EUS-guided fine-needle aspiration has rapidly spread as a minimally invasive procedure. Especially in patients with failed endoscopic retrograde cholangiopancreatography, EUS-guided biliary intervention is reported to be useful as salvage therapy. EUS-guided biliary interventions are carried out using three techniques: EUS-guided bilioenteric anastomosis, EUS-guided rendezvous procedure, and EUS-guided antegrade treatment. Although interventional EUS is not yet a standardized procedure, there have been recent advances in this field that address various biliary diseases. Here, we summarize the indications, techniques, clinical results of previous studies, and future perspectives.

关键词： Endosonography-guided biliary intervention Choledo

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Clinical analysis of high serum IgE in autoimmune pancreatitis

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World Journal of Gastroenterology 2010年第41期16卷 5241-5246页

作者： Kenji Hirano Minoru Tada Hiroyuki Isayama Kazumichi kawakubo Hiroshi Yagioka Takashi Sasaki Hirofumi Kogure Yousuke Nakai Naoki Sasahira Takeshi Tsujino Nobuo Toda Kazuhiko Koike Department of Gastroenterology University of Tokyo 7-3-1 HongoBunkyo-ku Tokyo 113-8655 Japan De-partment of Gastroenterology University of Tokyo 7-3-1 HongoBunkyo-ku Tokyo 113-8655 Japan Department of Gastroenterology JR Tokyo General Hospital Tokyo 151-8528 Japan Department of Gastroenterology Mitsui Memo-rial Hospital Tokyo 101-8643 Japan

AIM: To clarify the clinical significance of high serum IgE in autoimmune pancreatitis (AIP). METHODS: Forty-two AIP patients, whose IgE was measured before steroid treatment, were analyzed. To evaluate the relationship between IgE levels and the disease activity of AIP, we examined (1) Frequency of high IgE (> 170 IU/mL) and concomitant allergic dis-eases requiring treatment; (2) Correlations between IgG, IgG4, and IgE; (3) Relationship between the presence of extrapancreatic lesions and IgE; (4) Re-lationship between clinical relapse and IgE in patients treated with steroids, and (5) Transition of IgE before and after steroid treatment. RESULTS: IgE was elevated in 36/42 (86%) *** allergic disease was observed in seven patients (allergic rhinitis in three, bronchial asthma in three, and urticaria in one). There were no signifi-cant correlations between IgG, IgG4, and IgE (r = -0.168 for IgG, and r = -0.188 for IgG4). There was no significant difference in IgE in the patients with and without extrapancreatic lesions (526 ± 531 IU/mL vs 819 ± 768 IU/mL, P = 0.163), with and without clini-cal relapse (457 ± 346 IU/mL vs 784 ± 786 IU/mL, P = 0.374). There was no significant difference in IgE between before and after steroid treatment (723 ± 744 IU/mL vs 673 ± 660 IU/mL, P = 0.633). CONCLUSION: Although IgE does not necessarily reflect the disease activity, IgE might be useful for the diagnosis of AIP in an inactive stage.

关键词： IgE IgG4 IgG Autoimmune pancreatitis

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Effect of age on aortic atherosclerosis

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Journal of Geriatric Cardiology 2013年第2期10卷 135-140页

作者： Michael A. Chen Miwa kawakubo Patrick M. Colletti Dongxiang Xu Laurie LaBree Dustin Robert Detrano Stanley P Azen Nathan D. Wong Xue-Qiao Zhao Department of Medicine Division of Cardiology Harborview Medical Center/University of Washington 325 9th Avenue Box 359748 Seattle WA 98104 USA Department of Preventive Medicine Division of Biostatistics Keck School of Medicine of the University of Southern California 2001 N Soto Street SSB 201A M/C 9234 Los Angeles CA 90089-9237 USA Department of Radiology Keck School of Medicine of the University of Southern California1 1500 San Pablo Street Second Floor Imaging Los Angeles CA 90033 USA Department of Radiology University of Washington School of Medicine Box 357115 1959 Pacific Street RR-215 Seattle WA 98195-7117 USA Department of Radiological Sciences University of California Irvine School of Medicine 101 the City Drive South Route 140 Orange CA 92868 USA Department of Medicine UC Irvine School of Medicine 333 City Blvd. West Suite 400 Orange CA 92868-3298 USA

Objective To examine the association of atherosclerosis burden in the survivors of an asymptomatic elderly cohort study and its relationship to other coronary risk factors (specifically, age) by evaluating aortic atherosclerotic wall burden by magnetic resonance imaging (MRI). Methods A total of 312 participants in an ongoing observational cohort study underwent cardiac and descending thoracic aorta imaging by MRI. Maximum wall thickness was measured and the mean wall thickness ***/outer wall ratio was used as a normalized wall index (NWI) adjusted for artery size difference among participants. Percent wall volume (PWV) was calculated as NWI ×*** In this asymptomatic cohort (mean age: 76 years), the mean (SD) aortic wall area andwall thicknesswere 222 ±45 mm2 and 2.7 ±0.4 mm, respectively. Maximum wall thickness was 3.4 ±0.6 mm, and PWV was 32% ±4%. Women appeared to have smaller wall area,but after correcting for their smaller artery size, had significantly higher PWV than men (P = 0.03). Older age was associatedwith larger wall area (P = 0.04 for trend) with similar PWVs. However, there were no statistically significant associations between standard risk factors,Framingham global risk, or metabolic syndrome status, therapy for cholesterol or hypertension, coronary or aortic calcium score, and the aortic wall burden. Aortic calcificationwas associated with coronary calcification. Conclusions Asymptomatic elderly in this cohort had a greater descending thoracic aortic wall volume that correlated with age, andwomen had a significantly increased PWV compared to men. In these survivors, the atherosclerotic aortic wall burden was not significantly associated with traditional risk factors or with coronary or aortic calcium scores or coronary calcium progression. Results suggest that age, or as yet unidentified risk factor(s), may be responsible for the increase in atherosclerosis.

关键词： Aging Aortic atherosclerosis Atherosclerotic risk factors Magnetic resonance imaging

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