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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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Molecular Phylogeny and Evolution of Two Rhacophorus Species Endemic to Mainland Japan

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Asian Herpetological Research 2019年第2期10卷 86-104页

作者： Masafumi MATSUI Yasuhiro KAWAHARA Kanto NISHIKAWA Seiji IKEDA Koshiro ETO Yusuke mizuno Graduate School of Human and Environmental Studies Kyoto UniversityYoshida Nihonmatsu-choSakyo-kuKyoto 606-8501Japan Hagi City Museum Horiuchi 355HagiYamaguchi 758-0057Japan Hiroshima University Museum Kagamiyama 1-1-1Higashi Hiroshima CityHiroshima 739-8524Japan Kitakyushu Museum of Natural History and Human History Higashida 2-4-1Yahatahigashi-kuKitakyushuFukuoka 805-0071Japan Takahari 4-1002 Meito-kuNagoya 465-0061Japan

We conducted molecular phylogenetic analyses of Japanese Rhacophorus species, especially of R. schlegelii and R. arboreus from the mainland, based on samples encompassing their known distribution ranges, and discussed about evolutionary history of Rhacophorus species within Japan. The common ancestor of Japanese Rhacophorus, except for R. owstoni from southern Ryukyus, was estimated to have diverged from a lineage occurring mainly in China about 7 MYBP. Both R. schlegelii and R. arboreus are genetically largely divergent between regions of eastern and western Japan, and this seems to have been promoted mainly by retreat to refugia. Retreats of the two species to different refugia sometimes in the past seem to have led restricted distribution of R. schlegelii in eastern and R. arboreus in western Japan, and brought their intraspecific variation patterns in morphology and breeding habit.

关键词： glacial period mitochondrial DNA differentiation refugia Rhacophorus arboreus Rhacophorus schlegelii

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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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Acute respiratory distress syndrome associated with severe ulcerative colitis

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World Journal of Gastroenterology 2010年第19期16卷 2440-2442页

作者： Shiho Sagara Yasuo Horie Yumiko Anezaki hideaki Miyazawa Masahiro Iizuka Health Care Center Akita Red Cross Hospital Akita 010-0001 Japan Department of Internal Medicine Akita University School of Medicine Akita 010-8543 Japan Department of Surgery Akita University School of Medicine Akita 010-8543 Japan

Various extraintestinal manifestations including pulmonary abnormalities have been reported in patients with ulcerative colitis. Acute respiratory distress syndrome (ARDS) is a serious and fatal pulmonary manifestation. We have experienced a 67-year-old male patient with ARDS associated with a severe type of ulcerative colitis (UC). Severe dyspnea symptoms occurred during the treatment of UC in a previous hospital and the patient was transferred to our hospital on June 27, 2007. Both blood and sputa cultures for bacteria and fungi were negative. Cytomega-lovirus antigenemia was also not detected. From the clinical and radiological [Chest X-ray, computed tomography (CT)] findings, the patient was diagnosed with ARDS on the basis of the def inition of ARDS developed by the European-American Consensus Conference on ARDS. Both colonic inflammations and ARDS symptoms of the patient were resistant to any medical treatment includingcorticosteroids and antibiotics. However, ARDS symptoms were dramatically improved after surgical colectomy. We believe that severe colonic inflammation from UC was closely associated with the onset of ARDS of the patient. Our case report suggests that a severe type of ulcerative colitis might be taken into consideration as one of the predisposing factors of ARDS.

关键词： Acute respiratory distress syndrome Ulcerative colitis Inflammatory bowel disease Extra-intestinal manifestation

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Quantitative Analysis of the Removal Ratio of Fine Particles in Water by Gas Bubbling

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Journal of Iron and Steel Research International 2011年第S2期18卷 331-334页

作者： Masafumi Miyazaki hideaki Yamamura Satoru Mineta Takehiko Toh Environment & Process Technology Center Technical Development Bureau Nippon Steel Corp. Japan Advanced Technology Research Lab. Technical Development Bureau Nippon Steel Corp. Japan

Removal of non-metallic inclusions in molten steel is important from the viewpoint of improvement of quality, property and yield of the products. As a removal method of inclusions from molten metal, gas bubble flotation adhering inclusions is well known. Gas bubbling is particularly effective for the removal of fine inclusions. Water model experiment is reported the quantitative analysis of the removal ratio of dispersed particles removed from water by gas bubbles.

关键词： inclusion gas bubble water model experiment removal constant collision attachment

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Inflammatory fibroid polyp occurring in the transverse colon diagnosed by endoscopic biopsy

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World Journal of Gastroenterology 2007年第27期13卷 3765-3766页

作者： Shoji Hirasaki Minoru Matsubara Fusao Ikeda hideaki Taniguchi Seiyuu Suzuki Second Department of Internal Medicine Sumitomo Besshi Hospital 3-1 Ohji-cho Niihama 792-8543 Japan

A case of an inflammatory fibroid polyp occurring in the transverse colon and diagnosed by endoscopic biopsy is reported. The patient was an 82-year-old man who visited our hospital for further evaluation of occult blood in stool. The Colonoscopy revealed a small, red, and peduncular polyp, about 6 mm in diameter, in the transverse colon. Histological examination of the biopsy specimen obtained from the polyp revealed proliferation of fibroblasts and infiltration of inflammatory cells such as plasma cells and eosinophils. This polyp was diagnosed as an inflammatory fibroid polyp, which can appear in many different locations throughout gastrointestinal tract, though still rare in the transverse colon.

关键词： Inflammatory fibroid polyp Colonoscopy Inflammation Type Ⅱ pit pattern

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Control of Snow Falling Flow around NACA0015 Blade using a Plasma Electrode with Weather Resistant Design

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Journal of Thermal Science 2022年第1期31卷 72-81页

作者： MATSUDA Hisashi CHIBA Takahiro YAGAMI Masaki TAJIMA Yusuke WATANABE Nobuyoshi SATO hideaki TAKEYAMA Masafumi Hokkaido University of Science Hokkaido 006-8585Japan Asahi Rubber Inc. Saitama 330-0801Japan

The plasma actuation (PA) effect on the snow falling flow was investigated using a plasma electrode with weather resistant design and the natural snow wind facility of the Hokkaido University of Science. NACA0015 test blade with chord length c of 300 mm was used. Wind tunnel tests were carried out under the angle of the attack of the blade was fixed at 15 degrees, and the main flow velocity is U=5 m/s. PIV (Particle image velocimetry) measurements were conducted on various PA conditions using natural dry snowflakes as a tracer. When the actuator was driven under the condition of the fundamental frequency of F=50 kHz, and the pulsed modulated frequency f of fc/U=1 and Duty ratio (Ratio of plasma ON time to pulse duration time) =1%, movement of snowflakes was controlled the most effectively tested. It was clarified that the fundamental frequency of PA also affects the control of snow flow. Under snowfall conditions, the weather resistant designed plasma electrode has suffered no damage and operated successfully.

关键词： plasma actuator weather resistant design snow falling flow control experiment PIV

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Management of gastric and duodenal neuroendocrine tumors

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World Journal of Gastroenterology 2016年第30期22卷 6817-6828页

作者： Yuichi Sato Satoru Hashimoto Ken-ichi mizuno Manabu Takeuchi Shuji Terai Department of Gastroenterology Niigata University Graduate School of Medical and Dental Sciences Division of Endoscopy Niigata University Medical and Dental Hospital

Gastrointestinal neuroendocrine tumors (GI-NETs) are rare neoplasms, like all NETs. However, the incidence of GI-NETS has been increasing in recent years. Gastric NETs (G-NETs) and duodenal NETs (D-NETs) are the common types of upper GI-NETs based on tumor location. G-NETs are classified into three distinct subgroups: type I, II, and III. Type I G-NETs, which are the most common subtype (70%-80% of all G-NETs), are associated with chronic atrophic gastritis, including autoimmune gastritis and Helicobacter pylori associated atrophic gastritis. Type II G-NETs (5%-6%) are associated with multiple endocrine neoplasia type 1 and Zollinger-Ellison syndrome (MEN1-ZES). Both type I and II G-NETs are related to hypergastrinemia, are small in size, occur in multiple numbers, and are generally benign. In contrast, type III G-NETs (10%-15%) are not associated with hypergastrinemia, are large-sized single tumors, and are usually malignant. Therefore, surgical resection and chemotherapy are generally necessary for type III G-NETs, while endoscopic resection and follow-up, which are acceptable for the treatment of most type I and II G-NETs, are only acceptable for small and well differentiated type III G-NETs. D-NETs include gastrinomas (50%-60%), somatostatin-producing tumors (15%), nonfunctional serotonin-containing tumors (20%), poorly differentiated neuroendocrine carcinomas (< 3%), and gangliocytic paragangliomas (< 2%). Most D-NETs are located in the first or second part of the duodenum, with 20% occurring in the periampullary region. Therapy for D-NETs is based on tumor size, location, histological grade, stage, and tumor type. While endoscopic resection may be considered for small nonfunctional D-NETs (G1) located in the higher papilla region, surgical resection is necessary for most other D-NETs. However, there is no consensus regarding the ideal treatment of D-NETs.

关键词： Gastric neuroendocrine tumors Duodenal neuroendocrine tumors Classification Endoscopic treatment Endoscopic submucosal dissection

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Modified magnetic resonance angiography of the liver using sensitivity encoding in comparison with digital subtraction angiography and CT arterial portography

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Hepatobiliary & Pancreatic Diseases International 2005年第2期4卷 185-191页

作者： Masahiko Fujii hideaki Kawamitsu Kazuro Sugimura First Affiliated Hospital Zhejiang University School of Medicine Hangzhou 310003 China Division of Ra diology Kobe Graduate School of Medicine Hyogo 6500017 Japan

BACKGROUND: Over 355 patients have received ortho- topic liver transplantation ( OLT) at this hospital since 1993. Preoperative imaging studies of both hepatic vessels and parenchyma in these recipients bettered surgical plan- ning or even precluded the necessity of surgery. Here we report our preliminary results of modified magnetic reso- nance angiography ( MRA ) using sensitivity encoding ( SENSE) through comparative study with conventional digital subtraction angiography (DSA) and CT arterial por- tography (CTAP). METHODS: Sixteen patients with suspected liver diseases were included in the study. All of them received both dy- namic MRI of the liver using SENSE and digital DSA with CTAP within a two-week interval. The four-phase MRA was reconstructed from source images of the coronal dy- namic study. The arterial phase of the modified MRA was compared with DSA in the evaluation of hepatic arteries and the portal phase compared with CT portography recon- structed from source images of CTAP. In dynamic study of the liver, a fixed dose (20 ml) of contrast medium and scan timing were used. RESULTS: The main branches and variations of the hepatic arterial system were well shown on the modified MRA, al- though the marginal branches of hepatic arteries were of poor quality. The figures of portal veins on MRA were as clear as or superior to those of CTAP. In addition, the su- prarenal inferior vena cava (IVC) was well demonstrated on MRA and/or non contrast-enhanced coronal balanced fast-field echo (b-FFE) scan sequence in most cases. MRI detected most parenchymal lesions of the liver and hemo- dynamics of these lesions could be evaluated on source ima- ges of the modified MRA. MRI/MRA also serendipitously revealed several extrahepatic disease entities or variations that were not found on DSA/CTAP. CONCLUSIONS: The modified MRA using SENSE is a cost-effective modality of examination for the demonstra- tion of the whole hepatic vascular system. Combined with MRI, it has t

关键词： orthotopic liver transplantation magnetic resonance imaging magnetic resonance angiography digital subtraction angiography

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Two -Dimensional Wavelength Selective Diffraction by High-Order Three-Dimensional Composite Grating

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光学学报 2003年第S1期23卷 295-296页

作者： Kohji Furuhashi hideaki Okayama Hirochika Nakajima School of Science and Technology Waseda University 3-4-1 Ohkubo Shinjyuku-ku Tokyo 169-8555 JapanSchool of Science and Technology Waseda University 3-4-1 Ohkubo Shinjyuku-ku Tokyo 169-8555 JapanOCC Oki Electric Industry Co. Ltd.School of Science and Technology Waseda University 3-4-1 Ohkubo Shinjyuku-ku Tokyo 169-8555 Japan

We propose a wavelength selective diffraction using reflectors placed on three-dimensional grid cross points. Different wavelengths are separated into spots distributed in two-dimensional plane. Compact device with hi... 详细信息

关键词： into with as by Dimensional Wavelength Selective Diffraction by High-Order Three-Dimensional Composite Grating Two high

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