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第十二届全国流体力学学术会议

作者： Vinod Ashok Thale Mostafa Abouelsoud marie-jean thoraval State key Laboratory for strength and vibration of mechanical structure International Center for Applied Mechanics School of Aerospace Xian Jiaotong University Mechanical engineering department Faculty of Engineering South Valley University

The impact of an air-liquid compound drop onto a liquid surface was investigated numerically, focusing on the vertical counter-jet emerging from the bottom of the bubble during impact. We systematically changed the depth of the liquid pool, bubble size and position, and liquid viscosity to observe their influences on the maximum jet velocity. It is observed that the jetting is strongly attenuated by the deformable liquid pool compared to the impact on a solid surface. In addition, a mathematical model was proposed to explain the jetting mechanism and how it is affected by the different parameters.

关键词： Air-in-liquid compound Drop VOF-simulation Drop Impact

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Hele-Shaw装置中单一气泡近竖直壁面上升过程实验研究

Hele-Shaw装置中单一气泡近竖直壁面上升过程实验研究

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第十二届全国流体力学学术会议

作者：菅振向诗评 Abderrahmane Kherbeche marie-jean thoraval 西安交通大学航天航空学院工程力学系机械结构强度与振动国家重点实验室国际应用力学中心 Université Paris-Est Laboratoire Géomatériaux et Environnement(EA4508)UPEM

本文利用高速摄像实验技术研究了二维Hele-Shaw装置中单一气泡近竖直壁面上升过程,建立了考虑附加质量效应的力平衡方程,查清了气泡几何及动力学特征量的时间演化规律,揭示了壁面对气泡上升动力学过程的影响机制。利用流变液,观察到了... 详细信息

本文利用高速摄像实验技术研究了二维Hele-Shaw装置中单一气泡近竖直壁面上升过程,建立了考虑附加质量效应的力平衡方程,查清了气泡几何及动力学特征量的时间演化规律,揭示了壁面对气泡上升动力学过程的影响机制。利用流变液,观察到了气泡上升过程清晰尾迹结构。实验中发现,气泡被释放后首先竖直上升,然后开始之字形摆动,并逐渐远离壁面。从尾迹结构的时空演化角度来看,气泡释放后首先形成直线尾迹,随后在气泡后部形成附着对称涡对,然后漩涡脱落触发之字形摆动,并最终形成卡门涡街,竖直壁面导致近壁区复杂尾迹结构的产生。

关键词：气泡 Hele-Shaw 壁面尾迹卡门涡街

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On the dynamics of air filament contraction

On the dynamics of air filament contraction

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第十一届全国流体力学学术会议

作者：邓鹏菅振 marie-jean thoraval 西安交通大学航天航空学院国际应用力学中心

The contraction of an air filament surrounded by liquid is studied by direct numerical simulation with the open source code Basilisk.A steady air filament will contract under the action of surface *** dynamics will depend on the Ohnesorge number and the aspect ratio of the *** contraction velocity will increase to a maximum and then *** to capillary instability,the long filament will break up into *** maximum contraction velocity and time needed to attain the maximum velocity and time for breakup have different scaling in function of the Ohnesorge number.A transition from capillary-inertia scaling to capillary-viscous scaling is *** filament can contract into a bubble or break up into multiple bubbles,the fate is depended by Ohnesorge number and aspect ratio of *** short filament and highly viscous filament,they will not break *** filament with low Ohnesorge number,the oscillation of the final bubble can shed vortex into the liquid,forming a vortex ring.A phase diagram is developed to elucidate the breakup length threshold for different Ohnesorge number.

关键词： drops and bubbles

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Vorticity effects in drop impact

Vorticity effects in drop impact

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第九届全国流体力学学术会议

作者： marie-jean thoraval Sigurdur T.THORODDSEN International Center for Applied Mechanics State Key Laboratory for Strength and Vibration of Mechanical StructuresXi'an Jiaotong University Division of Physical Sciences and Engineering & Clean Combustion Research Center King Abdullah University of Science and Technology(KAUST)

The impact of drop on a liquid pool can entrap bubbles and splash smaller *** bubbles can dissolve and transfer gas into the pool,while the droplets can generate *** studies on drop impacts have neglected the effect of vorticity on the *** were able to reproduce the large scale dynamics of the drop entering the ***,recent results have demonstrated that the vorticity produced at the air-liquid interface plays a critical role in explaining the complex dynamics of splashing and air *** focus here on the dynamics of the air bubble entrapped just after contact between the drop and the *** show the role of vorticity in producing a large range of different bubble shape,including toroidal bubbles,and bubbles containing a liquid droplet

关键词： Drop impact Air Entrapment Splashing Vorticity Vortex Ring

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液滴撞击固体壁面导致飞溅的机理研究

液滴撞击固体壁面导致飞溅的机理研究

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第十届全国流体力学学术会议

作者：菅振 Christophe Josserand Stephane Popinet Pascal Ray Stephane Zaleski marie-jean thoraval 西安交通大学航天航空学院机械结构强度与振动国家重点实验室国际应用力学中心 Sorbonne Universites UPMC Universite Paris 06CNRSUMR 7190Institut Jean Le Rond d'Alembert LadHyX CNRSEcole PolytechniqueUMR 7646

液滴撞击现象广泛存在于土壤侵蚀、雾化及喷墨印刷等自然现象和工业应用中。由于实验中液体和气体间密度及粘度比数值较大,理论分析时通常忽略气体对液滴撞击的影响。最新的实验结果表明,仅通过降低气体压强就可完全消除液滴撞击导致的... 详细信息

液滴撞击现象广泛存在于土壤侵蚀、雾化及喷墨印刷等自然现象和工业应用中。由于实验中液体和气体间密度及粘度比数值较大,理论分析时通常忽略气体对液滴撞击的影响。最新的实验结果表明,仅通过降低气体压强就可完全消除液滴撞击导致的飞溅现象,气体也是液滴飞溅现象的决定性因素。本文通过基于开源代码Gerris的数值模拟方法研究液滴撞击过程中气体对飞溅现象的影响。本文计算结果表明,气体主要通过液滴下气体层粘性效应所致的缓冲作用影响飞溅过程,同时气体的惯性效应也对飞溅现象产生影响。根据液滴接触固体壁面前是否会产生射流,本文提出了两种不同的飞溅机理,通过系统性改变气体粘度和密度值得到了液滴飞溅模式的转换相图。

关键词：液滴撞击飞溅气体 Gerris 体积分数法

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液滴撞击液池所致被捕获空气盘的动力学研究

液滴撞击液池所致被捕获空气盘的动力学研究

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第十一届全国流体力学学术会议

作者：菅振 Murad Ali Channa Abderrahmane Kherbeche Hossain Chizari Sigurdur T.Thoroddsen marie-jean thoraval 西安交通大学航天航空学院机械结构强度与振动国家重点实验室国际应用力学中心 Division of Physical Sciences and Engineering King Abdullah University of Science and Technology(KAUST)

液滴撞击液池过程中,一定量空气在液滴与液池间被捕获并形成空气圆盘,最终收缩为中心气泡。本文采用高速摄像实验技术和高精度数值模拟研究不同物性和撞击条件下,被捕获空气圆盘的收缩过程。揭示了被捕获空气圆盘收缩为中心气泡的动力... 详细信息

液滴撞击液池过程中,一定量空气在液滴与液池间被捕获并形成空气圆盘,最终收缩为中心气泡。本文采用高速摄像实验技术和高精度数值模拟研究不同物性和撞击条件下,被捕获空气圆盘的收缩过程。揭示了被捕获空气圆盘收缩为中心气泡的动力学过程,发现了生成单一气泡、生成环状气泡、垂直分裂为两个子气泡等空气盘收缩的不同模态;定义了基于被捕获空气层平均厚度的局部Ohnesorge数Ohe,构建了基于Re数和We数的模态演化参数空间,建立了基于Ohe数的被捕获空气圆盘不同收缩模态间相互转化的无量纲标度率;提出了气泡垂直分裂的机理解释,发现对于低Ohe数的情况,被捕获空气层收缩过程中产生的涡脱落现象能阻止气泡的垂直分裂,并使气泡沿液滴撞击反方向上升或对抗浮力下降。

关键词：液滴撞击气泡气体捕获空气盘涡脱落

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Large Bubble Entrainment in Drop Impact on a Pool

Large Bubble Entrainment in Drop Impact on a Pool

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第十四届全国物理力学学术会议

作者： thoraval marie-jean LI Yang-Fan THORODDSEN Sigurdur T International Center for Applied Mechanics State Key Laboratory for Strength and Vibration of Mechanical StructuresXi'an Jiaotong University Mechanical Engineering National University of Singapore Division of Physical Sciences and Engineering & Clean Combustion Research Center King Abdullah University of Science and Technology(KAUST)

A drop impacting onto a pool of the same liquid can entrap air bubbles in many different ways.A peculiar entrapment was observed by Pumphrey and Elmore and remained unexplained until *** a small range of *** cavity produced by the impacting drop spreads radially in a dish-shape and then closes to entrap a bubble larger than the *** demonstrate that this large bubble entrapment is caused by a vortex ring produced at the highly curved air-liquid interface during the impact of the *** combine experiments and numerical simulations to show that the vortex ring pulls on the interface on the side of the cavity to stretch it radially,explaining the shape of the *** show that this type of bubble entrapment is only observed for prolate drops,*** elongated.A strong vortex ring is necessary to produce the large bubble entrapment,as a stronger vortex ring will lead to a stronger pulling on the ***,the strength of the vortex ring is not enough to explain the large bubble ***,flatter drops produce a stronger vortex ring,but do not entrap a large *** that case,the stronger vortex ring interacts strongly with the pool surface and self-destruct earlier,before being able to deform the cavity below the pool *** the strength of the vortex ring,its dynamics also plays a critical role in the large bubble *** dynamics of the vortex ring and its distance to the interface are strongly affected by the shape of the drop,explaining why the large bubble entrapment can be observed only for prolate *** observations also explain why the strongest and most penetrating vortex rings emerging from drop impacts are not produced by oblate drops but by more prolate drop shapes,as had been observed in previous *** regular bubble entrapment is caused by the hydrostatic pressure due to *** can be verified easily by removing gravity in the numerical *** is not the case for

关键词： insulating engineering ceramics electrical discharge machining temperature gradient thermal stress numerical simulation

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Role of immunosuppression and tumor differentiation in predicting recurrence after liver transplantation for hepatocellular carcinoma: A multicenter study of 412 patients

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World Journal of Gastroenterology 2006年第45期12卷 7319-7325页

作者： Thomas Decaens Franoise Roudot-thoraval Solange Bresson-Hadni Carole Meyer jean Gugenheim Francois Durand Pierre-Henri Bernard Olivier Boillot Philippe Compagnon Yvon Calmus jean Hardwigsen Christian Ducerf Georges Philippe Pageaux Sébastien Dharancy Olivier Chazouillères Daniel Cherqui Christophe Duvoux Service d'Hépatologie et de Gastroentérologie AP-HP Hpital Henri Mondor Créteil Unité INSERM 581 France Département de Santé Publique AP-HP Hpital Henri Mondor Créteil France Service d’Hépatologie Hpital Jean Minjoz Besanon France Service de Transplantation Hpital HautefeuilleStrasbourg France Service de Chirurgie Digestive Hpital L’Ar-chet 2 Nice France Service d’Hépatologie AP-HP Hpital Beau-jon Clichy France Service d’Hépatologie et de Gastroentéro-logie H?pital Pellegrin Bordeaux France Service de Chirurgie Digestive Hpital Edouard Herriot Lyon France Service de Chirurgie Digestive Hpital Ponchaillou Rennes France Service de Chirurgie Digestive AP-HP HpitalCochin Paris France Service de Chirurgie Digestive Hpital laConception Marseille France Service de Chirurgie Digestive Hpital de laCroix Rousse Lyon France Fédération Médico-Chirurgicale deMaladies de l’Appareil Digestif Hpital Saint-Eloi MontpellierFrance Service d’Hépatologie et de Gastroentérologie H?pital Claude Huriez Lille France Service d’Hépatologie AP-HP Hpital SAntoine Paris France Service de Chirurgie Générale et Digestive APHP Hopital Henri Mondor Créteil France

AIM: To assess pre-orthotopic liver transplantation (OLT) factors that could be evaluated pre-operatively or con- trolled post-operatively associated with hepatocellular carcinoma (HCC) recurrence and disease-free survival after liver transplantation (LT).METHODS: Four hundred and twelve patients trans- planted for HCC between 1988 and 1998 in 14 French centers, who survived the postoperative period were studied. Kaplan Meier estimates were calculated for 24 variables potentially associated with recurrence of HCC. Uni- and multivariate analyses were conducted to iden- tify independent predictors of recurrence. RESULTS: Overall 5-year disease-free survival was 57.1%. By univariate analysis, variables associated with disease-free survival were: presence of cirrhosis (P = 0.001), etiology of liver disease (P = 0.03), α fetoprotein level ( 2000; P 2N; P = 0.02), the number of nodules (1, 2-3 or ≥ 4; P = 0.02), maximal diameter of the largest nodule ( 5 cm; P 10 cm; P < 0.0001), bi- lobar location (P = 0.01), preoperative portal thrombosis (P < 0.0001), peri-operative treatment of the tumor (P = 0.002) and chemoembolization (P = 0.03), tumor differentiation (P = 0.01), initial type of calcineurin inhibitor (P = 0.003), the use of antilymphocyte antibodies (P = 0.02), rejection episodes (P = 0.003) and period of LT (P < 0.0001). By multivariate analysis, 6 variables were independently associated with HCC recurrence: maximal diameter of the largest nodule (P < 0.0001), time of LT (P < 0.0001), tumor differentiation (P < 0.0001), use of anti-lymphocyte antibody (ATG) or anti-CD3 antibody (OKT3) (P = 0.005), preoperative portal thrombosis (P = 0.06) and the number of nodules (P = 0.06). CONCLUSION: This study identif ies immunosuppression, through the use of ATG or OKT3, as a predictive factor of tumor re

关键词：免疫抑制肝细胞癌肝移植分化

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激素治疗酒精性肝炎的新预测因素:低度脂肪变性和门脉血流显著改变

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世界核心医学期刊文摘（胃肠病学分册） 2005年第5期1卷 32-32页

作者： Duvoux C. Radier C. Roudot-thoraval F. 李翔 Serv. d’Hepatol./de Gastroenterol. Unite de Transplantation Hepatique Hpital Henri Mondor 51 Ave. Marechal Lattre de Tassigny 94010 Créteil France Dr

The aim of this study was to assess the prevalence and prognostic value of major alterations of portal flow in patients with steroid-treated alcoholic hepatitis. Fifty patients with severe, histologically proven alcoholic hepatitis were enrolled. Clinical data, liver test results, and hepatic Doppler ultrasound findings were collected at inclusion and at month 2. Patients were followed for 1 year or until death. Major changes in portal flow were defined as reversed or alternating flow in the portal trunk and/or in intrahepatic portal branches. Changes in portal flow were observed in 24 (48.0%) of 50 and 17 (39.5%) of 43 patients at inclusion and month 2, respectively. Univariate analysis showed that age older than 50 years, steatosis less than 20%on initial liver biopsy, presence of major changes in portal flow, Child-Turcotte-Pugh score higher than 12, factor V level higher than 45%, and hepatofugal splenic blood flow were associated with a lower 1-year survival. Cox regression analysis showed that steatosis < 20%(relative hazard [RH] = 9.3, P = .0009) and major changes in portal flow (RH = 3.1,P= .04), were independently associated with poor survival. In conclusion, major changes in portal flow are frequent in patients with severe alcoholic hepatitis. Altered portal flow and steatosis < 20%are new prognostic factors in steroid-treated alcoholic hepatitis and must be taken into account in patient management.

关键词：酒精性肝炎脂肪变性肝内门静脉多普勒超声检查预测价值单变量分析相对风险中门临床资料

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每日吸食大麻是慢性丙型肝炎患者肝纤维化进展的危险因素

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世界核心医学期刊文摘（胃肠病学分册） 2005年第10期1卷 39-39页

作者： Hézode C. Roudot-thoraval F. Nguyen S. A. Mallat 李翔 Service d'Hépatologie et de Gastroentér-ologie Centre Hospitalier Universitaire Henri Mondor 51 ave. Marechal Lattre Tassigny 94010 Créteil Cedex France

Cannabinoids present in Cannabis sativa (marijuana) exert biological effects via cannabinoid receptors CB1 and CB2. We recently demonstrated that CB1 and CB2 receptors regulate progression of experimental liver fibrosis. We therefore investigated the impact of cannabis smoking on fibrosis progression rate in patients with chronic hepatitis C (CHC). Two hundred seventy consecutive untreated patients with CHC of known duration undergoing liver biopsy were studied. Demographic, epidemiological,metabolic, and virological data were recorded, and detailed histories of cannabis, alcohol, and tobacco use over the span of hepatitis C virus infection were obtained. Fibrosis stage, steatosis, and activity grades were scored according to Metavir system. Patientswere categorized as noncannabis users (52.2%), occasional users (14.8%), or daily users (33.0%), and the relationship between cannabis use and fibrosis progression rate (FPR) or fibrosis stage was assessed. On multivariate analysis, six factors were independently related to a FPR greater than 0.074 (median value of the cohort): daily cannabis use (OR = 3.4 [1.5-7.4]), Metavir activity grade A2 or higher (OR = 5.4 [2.9-10.3]), age at contamination of more than 40 years (OR = 10.5 [3.0-37.1]), genotype 3 (OR = 3.4 [1.5-7.7]), excessive alcohol intake (OR = 2.2 [1.1-4.5]), and steatosis (OR = 2.0 [1.0-4.1]). Daily cannabis use was also an independent predictor of a rapid FPR ( >0.15) (OR = 3.6 [1.5-7.5]). Finally, severe fibrosis (≥F3) was also predicted by daily cannabis use (OR = 2.5 [1.1-5.6]; P = .034), independently of Metavir activity grade, excessive alcohol intake, age at liver biopsy, steatosis, and tobacco smoking. In conclusion, daily cannabis smoking is significantly associated with fibrosis progression during CHC. Patients with ongoing CHC should be advised to refrain from regular cannabis use.

关键词：慢性丙型肝炎肝纤维化肝组织活检脂肪变性详细病史活动程度研究人群进展率人口统计学吸食者

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