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基于PIV的船首气泡下扫现象试验研究 被引量:2
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作者 张福民 张勇 +2 位作者 魏少鹏 郭春雨 赵庆新 《舰船科学技术》 北大核心 2016年第12期26-29,共4页
以某载人潜水器支持母船为研究对象,通过气泡发生器产生气泡来模拟该船在正常航行时的气泡条件,气泡的位置通过PIV测量系统观测与拍摄,从而捕捉到气泡流的运动轨迹。通过对试验结果的分析,较为有效的显现了气泡下扫以及气泡流迹的现象,... 以某载人潜水器支持母船为研究对象,通过气泡发生器产生气泡来模拟该船在正常航行时的气泡条件,气泡的位置通过PIV测量系统观测与拍摄,从而捕捉到气泡流的运动轨迹。通过对试验结果的分析,较为有效的显现了气泡下扫以及气泡流迹的现象,同时证明了船体邻近水域内气泡流迹并不是简单的水平和垂向速度的合成。 展开更多
关键词 气泡发生器 PIV 下扫 气泡流迹
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转捩边界层中的上喷下扫运动
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作者 陈林 袁湘江 《计算物理》 CSCD 北大核心 2013年第1期53-60,共8页
采用高精度直接数值模拟方法,研究平板可压缩流边界层转捩后期过程中的上喷和下扫运动.模拟结果清楚地显示了边界层转捩过程中的上喷下扫运动的复杂现象,展示与典型涡系及尖峰结构的紧密联系.详细剖析多层次的上喷下扫运动的形成机制,... 采用高精度直接数值模拟方法,研究平板可压缩流边界层转捩后期过程中的上喷和下扫运动.模拟结果清楚地显示了边界层转捩过程中的上喷下扫运动的复杂现象,展示与典型涡系及尖峰结构的紧密联系.详细剖析多层次的上喷下扫运动的形成机制,数值结果证实了实验的新发现,并进行相应的机理分析. 展开更多
关键词 边界层 转捩 上喷 下扫 直接数值模拟
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明渠湍流涡运动尺度分布特性 被引量:10
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作者 张鹏 杨胜发 +2 位作者 胡江 陈阳 幸韵 《水科学进展》 EI CAS CSCD 北大核心 2015年第1期91-98,共8页
为了解明渠湍流涡运动尺度沿水深的分布特征,使用高精度粒子图像测速法水槽试验系统测量充分发展的明渠湍流,利用改进后的功率谱分析方法,对明渠湍流涡运动尺度沿水深分布、上升流、下扫流和平均涡量等进行了分析。结果表明:明渠湍流涡... 为了解明渠湍流涡运动尺度沿水深的分布特征,使用高精度粒子图像测速法水槽试验系统测量充分发展的明渠湍流,利用改进后的功率谱分析方法,对明渠湍流涡运动尺度沿水深分布、上升流、下扫流和平均涡量等进行了分析。结果表明:明渠湍流涡运动尺度大小沿水深增加呈先增大后减小;沿水深增加下扫流比上升流更容易发生;各自水深的顺向涡涡量大于逆向涡涡量,在近壁区平均涡量最大;明渠湍流近壁区产生涡量大、尺度小的涡结构,沿水深增加,涡尺度发展变大,但受水面区下扫流抑制,涡尺度又变小。 展开更多
关键词 明渠 湍流 涡尺度 功率谱 上升流 下扫
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“菊池思想”剖析
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作者 黄祥喜 《现代图书情报技术》 1983年第4期22-26,共5页
关键词 检索词 级位 标识词 提问式 不等价 下扫 不符合条件 LEVEL 通用字符 文献记录
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浸入式水口内壁特征对边界层流场结构和氧化铝夹杂物运动行为的影响 被引量:4
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作者 华承健 王敏 +2 位作者 张孟昀 郑瑞轩 包燕平 《工程科学学报》 EI CSCD 北大核心 2021年第7期925-934,共10页
铝镇静钢液浇注过程中,浸入式水口耐材内壁特征受到钢液侵蚀和夹杂物聚集影响,从近光滑壁面逐渐向多孔耐火材料壁面和含结瘤物的粗糙结瘤壁面转变,壁面形貌的变化影响边界层流场结构和氧化铝夹杂物的输运.采用物理模拟的方法在浸入式水... 铝镇静钢液浇注过程中,浸入式水口耐材内壁特征受到钢液侵蚀和夹杂物聚集影响,从近光滑壁面逐渐向多孔耐火材料壁面和含结瘤物的粗糙结瘤壁面转变,壁面形貌的变化影响边界层流场结构和氧化铝夹杂物的输运.采用物理模拟的方法在浸入式水口模型内壁镶嵌多孔耐火材料结构和含结瘤物耐材壁面结构,结合粒子图像测速技术研究不同特征壁面附近流场边界层.使用MATLAB耦合流场测速结果和氧化铝夹杂物运动数学模型,研究了不同特征壁面的流场边界层中氧化铝夹杂物的运动轨迹.使用象限分析法确定了浸入式水口边界层流场存在上抛和下扫事件.氧化铝夹杂物位于下扫事件区域时,朝向壁面运动,粒径为1μm的氧化铝夹杂物在下扫事件中运动轨迹更接近壁面,增加了沉积的可能性;氧化铝夹杂物位于上抛事件区域时,远离壁面运动.多孔耐火材料壁面和结瘤壁面边界层内氧化铝夹杂物运动幅度大于光滑壁面边界层流场内氧化铝夹杂物运动幅度.壁面状态由近光滑壁面转变为多孔耐火材料和结瘤壁面时,流场边界层中下扫事件平面占比由10.17%增加到39.77%,上抛事件平面占比由32.96%减小到9.24%;同时,流场边界层中下扫事件发生的概率由25.83%增加到28.24%,这将加速氧化铝夹杂物在多孔耐火材料和结瘤壁面的沉积进程. 展开更多
关键词 浸入式水口结瘤 粒子图像测速 边界层 上抛事件 下扫事件 夹杂物运动轨迹
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故郷への旅
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作者 杨舒予 《外语教学》 1982年第2期82-83,73,共3页
列车闇中西走。時時拔黑煤煙窓吹込来变匂漂z列车旅客互见,喋何食。声流行歌放送疲楽旅娱楽気分出谐刀每统俗笥乙 P●k泊。
关键词 列车旅客 声流 行歌 黑煤 达人 简元 人法 老人 私法 下扫
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建国三十五周年记事诗六首
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作者 吴蕴章 《江苏师范大学学报(哲学社会科学版)》 1984年第3期31-31,共1页
关键词 建国 周年 鸭绿江 群英会 纯钢 桃花源 下扫 成灰 正义 开车
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鞭杆对打(五)
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作者 毛明春 《搏击》 2007年第12期45-46,共2页
35、甲提膝弓步下戳、乙上步下扫虚步下压乙方右脚向前一步成弓步,同时右手持鞭由右上向左下扫击甲方的右腿胫部,左手扶于右腕部,目视鞭前端。甲方右腿提起,同时鞭前端向后摆左手接握,目视乙鞭。
关键词 甲方 目视 乙方 右脚 前端 腕部 左手 下扫 左脚 身体
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自卫防身九妙招
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作者 王天增 武兵 《搏击》 2008年第9期38-39,共2页
一、突遇歹徒施暴,歹徒上步进身,用双手掐锁我喉颈时;我疾变应动,用左、右手由外向里夹推其肘处,同时发右下扫踢腿猛踢歹徒前支撑腿内侧,将其踢倒在地,造成重创(图1、2、3)。要点:双手夹推肘有力,下扫踢腿准确,转腰闪身发力,手、脚相合... 一、突遇歹徒施暴,歹徒上步进身,用双手掐锁我喉颈时;我疾变应动,用左、右手由外向里夹推其肘处,同时发右下扫踢腿猛踢歹徒前支撑腿内侧,将其踢倒在地,造成重创(图1、2、3)。要点:双手夹推肘有力,下扫踢腿准确,转腰闪身发力,手、脚相合一致。 展开更多
关键词 歹徒 施暴 要点 发力 肘关节 支撑腿 下扫 自卫防身 踢腿 快速准确
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Enlarged accessory spleen presenting stomach submucosal tumor 被引量:4
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作者 Shunzen Chin Hajime Isomoto +3 位作者 Yohei Mizuta Chun-Yang Wen Saburo Shikuwa Shigeru Kohno 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第11期1752-1754,共3页
A 62-year-old man presented with upper abdominal discomfort underwent upper gastrointestinal endoscopy. Gastroscopy and endoscopic ultrasonography revealed a submucosal tumor (SMT) with homogenous echogenicity origina... A 62-year-old man presented with upper abdominal discomfort underwent upper gastrointestinal endoscopy. Gastroscopy and endoscopic ultrasonography revealed a submucosal tumor (SMT) with homogenous echogenicity originated from extragastric organs. An abdominal contrast-enhanced computed tomography (CT) showed that the well-marginated ovoid mass, approximately 6 cm in diameter, enhanced homogenously to a similar degree as splenic parenchyma. 99mTechnetium sulfur colloid scintigraphy revealed the splenic nature of the mass. A diagnosis of accessory spleen mimicking gastric SMT was made. Subsequent follow-up was uneventful without performing splenectomy. 展开更多
关键词 Accessory spleen ^99mTechnetium sulfur colloid scintigraphy Computed tomography Gastric submucosal tumor
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Endoscopic submucosal dissection for premalignant lesions and noninvasive early gastrointestinal cancers 被引量:23
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作者 Sadettin Hulagu Omer Senturk +16 位作者 Cem Aygun Orhan Kocaman Altay Celebi Tolga Konduk Deniz Koc Goktug Sirin Ugur Korkmaz Ali Erkan Duman Neslihan Bozkurt Gokhan Dindar Tan Attila Yesim Gurbuz Orhan TarcinDivision of Gastroenterology Derince State Hospital Kocaeli 41900 Turkey Cem Kalayci 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第13期1701-1709,共9页
AIM: To investigate the indication, feasibility, safety, and clinical utility of endoscopic submucosal dissection (ESD) in the management of various gastrointestinal pathologies. METHODS: The medical records of 60 con... AIM: To investigate the indication, feasibility, safety, and clinical utility of endoscopic submucosal dissection (ESD) in the management of various gastrointestinal pathologies. METHODS: The medical records of 60 consecutive patients (34 female, 26 male) who underwent ESD at the gastroenterology department of Kocaeli University from 2006-2010 were examined. Patients selected for ESDhad premalignant lesions or non-invasive early cancers of the gastrointestinal tract and had endoscopic and histological diagnoses. Early cancers were considered to be confined to the submucosa, with no lymph node involvement by means of computed tomography and endosonography. RESULTS: Sixty ESD procedures were performed. The indications were epithelial lesions (n = 39) (33/39 adenoma with high grade dysplasia, 6/39 adenoma with low grade dysplasia), neuroendocrine tumor (n = 7), cancer (n = 7) (5/7 early colorectal cancer, 2/7 early gastric cancer), granular cell tumor (n = 3), gastrointestinal stromal tumor (n = 2), and leiomyoma (n = 2). En bloc and piecemeal resection rates were 91.6% (55/60) and 8.3% (5/60), respectively. Complete and incomplete resection rates were 96.6% (58/60) and 3.3% (2/60), respectively. Complications were major bleeding [n = 3 (5%)] and perforations [n = 5 (8.3%)] (4 colon, 1 stomach). Two patients with colonic perforations and two patients with submucosal lymphatic and microvasculature invasion (1 gastric carcinoid tumor, 1 colonic adenocarcinoma) were referred to surgery. During a mean follow-up of 12 mo, 1 patient with adenoma with high grade dysplasia underwent a second ESD procedure to resect a local recurrence. CONCLUSION: ESD is a feasible and safe method for treatment of premalignant lesions and early malignant gastrointestinal epithelial and subepithelial lesions. Successful en bloc and complete resection of lesions yield high cure rates with low recurrence. 展开更多
关键词 Endoscopic submucosal dissection Premalignant gastrointestinal lesion Noninvasive early gastrointestinal cancer Neuroendocrine tumor Gastrointestinal stromal tumor
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A New Method for 3D Finite Element Modeling of Human Mandible Based on CT Data 被引量:1
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作者 于力牛 叶铭 王成焘 《Journal of Donghua University(English Edition)》 EI CAS 2004年第1期29-33,共5页
This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to ... This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to predict the stress and strain distribution in complex bone structures, but its accuracy strongly depends on the precision of input information. In geometric reconstruction, various methods of image processing, geometric modeling and finite element analysis are combined and extended. Emphasis is given to the assignment of the material properties based on the density values computed from CT data. Through this technique, the model with high geometric and material similarities were generated in an easy way. Consequently, the patient-specific FE model from mandible CT data is realized also. 展开更多
关键词 Computed Tomography MANDIBLE Three-Dimensional Finite Element Analysis
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Research of the underground coal bunker clearing robot
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作者 SONG Zhi-an ZHAN Feng +2 位作者 LI Cheng-yin WANG Ze-le ZHANG Shan-lin 《Journal of Coal Science & Engineering(China)》 2010年第1期104-107,共4页
With the long-term use of coal bunker, a certain amount of sticking objects will beformed on its wall, and coal mine clearing robot can replace man in clearing the bunker wall.Also, since it equip with an explosion-pr... With the long-term use of coal bunker, a certain amount of sticking objects will beformed on its wall, and coal mine clearing robot can replace man in clearing the bunker wall.Also, since it equip with an explosion-proof camera, the worker can determine the operationby observing the well-head monitor.Moreover, it cannot work unless it is placed in positionand supported stably, and it has three degrees of freedom: rotating, stretching, and shovelcoal.It is driven by the hydraulic and controlled by PLC.The underground coal mine clearingrobot changs the traditional clearing methods, man does not have to enter the bunker toclear it, which ensures the production safety of coal transportation. 展开更多
关键词 underground coal bunker clearing robot coal bunker coal transport
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用Tomo-TRPIV测量湍流边界层及拟序结构的空间模态 被引量:2
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作者 庄茜 姜楠 《实验力学》 CSCD 北大核心 2018年第3期359-365,共7页
层析时间分辨粒子图像测速(Tomographic Time-Resolved Particle Image Velocimetry,简称Tomo-TRPIV)技术是新近发展起来的一种先进的流体无接触测速技术,能够无干扰地测量流场的三个速度分量的三维空间分布。本文简要介绍了Tomo-TRPI... 层析时间分辨粒子图像测速(Tomographic Time-Resolved Particle Image Velocimetry,简称Tomo-TRPIV)技术是新近发展起来的一种先进的流体无接触测速技术,能够无干扰地测量流场的三个速度分量的三维空间分布。本文简要介绍了Tomo-TRPIV技术的基本原理、测量系统的主要组成和测量的主要步骤以及水槽中平板湍流边界层及其拟序结构的测量结果。实验证明,Tomo-TRPIV技术能够很好地测量平板湍流边界层对数律区的瞬时及平均流场,实验发现,在对数律区,平板湍流边界层中的拟序结构的涡量场主要以空间四极子的形式存在,四极子涡旋相互诱导,产生喷射和下扫等猝发事件,维持湍流边界层的发展演化。 展开更多
关键词 层析时间分辨粒子图像测速技术 湍流边界层 拟序结构 四极子 喷射 下扫 猝发
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A case report of diffuse pneumocephalus induced by sneezing after brain trauma
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作者 ZHANG Yun-xu LIU Iong-xi QIU Xiao-zhong 《Chinese Journal of Traumatology》 CAS CSCD 2013年第4期249-250,共2页
Pneumocephalus is the presence of air in the cranial vault. The common etiologies of pneumocephalus are brain trauma and cranial surgery. We report a case of a 26-year-old man with brain trauma who developed diffuse p... Pneumocephalus is the presence of air in the cranial vault. The common etiologies of pneumocephalus are brain trauma and cranial surgery. We report a case of a 26-year-old man with brain trauma who developed diffuse pneumocephalus after sneezing. CT scan was performed on arrival, and the image showed subarach- noid hemolxhage without pneumocephalus. On the seventh day after a big sneeze brain CT scan was re-performed, which showed pneumocephalus. After another ten days of treatment, the patient was discharged without any symptoms. 展开更多
关键词 PNEUMOCEPHALUS Brain injuries SNEEZING
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