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Implementation of a Roughness Element to Trip Transition in Large-eddy Simulation

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j.urnal of Thermal Science 2015年第1期24卷 30-36页

作者： j.Boudet j.-F.Monier F.Gao LMFA Ecole Centrale de Lyon Université de Lyon–UMR CNRS 5509 69134 Ecully Cedex France PhD.Candidate Université de Lyon–UMR CNRS 5509 69134 Ecully Cedex France

In aerodynamics, the laminar or turbulent regime of a boundary layer has a strong influence on friction or heat transfer. In practical applications, it is sometimes necessary to trip the transition to turbulent, and a common way is by use of a roughness element （e.g. a step） on the wall. The present paper is concerned with the numerical im- plementation of such a trip in large-eddy simulations. The study is carried out on a flat-plate boundary layer con- figuration, with Reynolds number Rex=l.3x 106. First, this work brings the opportunity to introduce a practical methodology to assess convergence in large-eddy simulations. Second, concerning the trip implementation, a volume source term is proposed and is shown to yield a smoother and faster transition than a grid step. Moreover, it is easier to implement and more adaptable. Finally, two subgrid-scale models are tested： the WALE model of nic0ud and Ducros （Flow Turbul. Combust., vol. 62, 1999） and the shear-improved Smagorinsky model of Ldv^que et al. （j. Fluid Mech., vol. 570, 2007）. Both models allow transition, but the former appears to yield a faster transition and a better prediction of friction in the turbulent regime.

关键词： large-eddy simulation boundary layer roughness element transition tripping

Recent progress on in situ characterizations of electrochemically intercalated transition metal dichalcogenides

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Nano Research 2019年第9期12卷 2126-2139页

作者： Saj.d Yazdani Milad Yarali j.dy j. Cha Department of Mechanical Engineering and Materials Science Yale UniversityNew HavenCT 06511USA Energy Sciences Institute Yale University West CampusWest HavenCT 06516USA

Layered transition metal dichalcogenides(TMDCs)have been extensively studied owing to their unique physical and chemical *** van der Waals(vdW)interact!ons betwee n the stacki ng layers of TMDCs allow intercalati on of various species including mono vale nt alkali,divale nt alkaline earth and multivale nt metal ions,zero-vale nt transiti on metals,as well as orga nic molecules,all of which can drastically alter fun dame ntal properties of the *** urge to understa nd the phe nomena and the desire to exploit them for applicati ons have inspired a great deal of investigations.A large portion of the mystery has been unveiled over the past decade of intense research;however,many questions remain open and require further *** review is concerned with investigations on structural and electronic evolution of TMDCs drive n by electrochemically con trolled in tercalati ***,we aim to survey the rece nt adva nces and experime ntal platforms for mon itoring the in tercalati on processes in situ by utilizi ng nano *** additi on,several in quiries and prospects are outlined in a broader con text for future ave nues of studies.

关键词： transition metal dichalcogenides electrochemical intercalation in situ characterizations transmission electron microscopy(TEM) magnetotransport measurements

Cerebral magnetic resonance imaging in quiescent Crohn's disease patients with fatigue

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World j.urnal of Gastroenterology 2017年第6期23卷 1018-1029页

作者： Sanne van Erp Ece Ercan Perla Breedveld Lianne Brakenhoff Eidrees Ghariq Sophie Schmid Matthias van Osch Mark van Buchem Bart Emmer j.roen van der Grond Ron Wolterbeek Daniel Hommes Herma Fidder nic van der Wee Tom Huizinga Désirée van der Heij.e Huub Middelkoop Itamar Ronen Andrea van der Meulen-de j.ng Department of Gastroenterology and Hepatology Leiden University Medical Center C.j.Gorter Center Leiden University Medical Center Department of Radiology Leiden University Medical Center Department of Medical Statistics Leiden University Medical Center Center for Inflammatory Bowel Diseases University of California Los Angeles Department of Gastroenterology and Hepatology University Medical Center Utrecht Department of Psychiatry Leiden University Medical Center Department of Rheumatology Leiden University Medical Center Department of Neuropsychology Leiden University Medical Center Department of Radiology Leiden University Medical CenterLeiden

To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI).METHODSMultiple MRI techniques were used to assess cerebral changes in 20 quiescent CD patients with fatigue (defined with at least 6 points out of an 11-point numeric rating scale compared with 17 healthy age and gender matched controls without fatigue. Furthermore, mental status was assessed by cognitive functioning, based on the neuropsychological inventory including the different domains global cognitive functioning, memory and executive functioning and in addition mood and quality of life scores. Cognitive functioning and mood status were correlated with MRI findings in the both study *** glutamate + glutamine (Glx = Glu + Gln) concentrations (P = 0.02) and ratios to total creatine (P = 0.02) were found in CD patients compared with controls. Significant increased Cerebral Blood Flow (P = 0.05) was found in CD patients (53.08 ± 6.14 mL/100 g/min) compared with controls (47.60 ± 8.62 mL/100 g/min). CD patients encountered significantly more depressive symptoms (P 1-weighted analysis. In addition, no correlation was found between mental status and MRI *** work shows evidence for perfusion, neurochemical and mental differences in the brain of CD patients with fatigue compared with healthy controls.

关键词： Magnetic resonance imaging Systemic inflammation Fatigue Crohn’s disease Cognition

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对岩石记录中三角洲和海岸平原的判别

大庆石油学院学报 1989年第4期13卷 1-10页

作者： j.亚历山大周书欣威尔士大学大庆石油学院

三角洲和海岸平原沉积可以通过在一个广阔区域中能足以判明三维相分布和不整合的岩石记录资料来相互区分。这个区别是建立在分布的基础上,而不是基于象过去那种纯理论上的由海相到河流冲积相的变化。对这两类环境沉积物的区别一般是很难... 详细信息

三角洲和海岸平原沉积可以通过在一个广阔区域中能足以判明三维相分布和不整合的岩石记录资料来相互区分。这个区别是建立在分布的基础上,而不是基于象过去那种纯理论上的由海相到河流冲积相的变化。对这两类环境沉积物的区别一般是很难的,甚至是不可能的。如果只是建立在有限资料上,将会导致不准确的结论,甚至可导致错误的相模式,使之引起对地下储层或煤层位置的预测出现问题。作为构造、海平面升降和自循环活动控制海岸平原的相分布模型来说,可被看作是岸线沉积类型之间的统一连续体的端员。以约克盆地中侏罗世的沉积岩为例说明由不确切的定义和不正确相模式的应用可引起的争论。中侏罗世的Ravenscar群在这里被解释为受构造和海平面升降影响的海岸平原沉积。浅海和非海相环境的反复波动被解释为受垂向构造运动和海平面变化引起的,而不是自循环过程所致。

关键词：岩石三角洲海岸平原储层

Intraoperative Periprosthetic Femoral Fractures Related to Austin Moore Hemiarthroplasty—A Retrospective Review of 365 Patients

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Open j.urnal of Orthopedics 2013年第3期3卷 189-192页

作者： j. A. Fernández-Valencia F. Llobet N. Pons I. López-Zabala X. Gallart G. Bori j. Riba Hip Unit at the Department of Orthopaedic Surgery Hospital Clínic University of Barcelona Barcelona Spain.

Intraoperative periprosthetic femoral fractures (IPFF) have been studied extensively for total hip arthroplasties, but not for hemiarthroplasties. Recent series in the literature show an IPFF rate for hemiarthroplasties ranging from 0% to 14%. The present study was designed to determine the prevalence and outcome after IPFF during non-cemented hemiarthroplasty. In addition, the surgical step at higher risk to produce these fractures was evaluated in an attempt to identify strategies that could minimize the prevalence of this complication. We performed an observational study of 365 consecutive patients undergoing and Austin-Moore hemiarthroplasty from 2005 to 2006 at our institution. The institutional IPFF rate was 6.8% (twenty-five out of 365). The moment at which the fracture was detected was collected: 1) intraoperatively and 2) in the postoperative radiological control. The surgical step in which the fracture occurred was collected: 1) neck osteotomy, 2) broaching, 3) prosthesis introduction, and 4) reduction. Results were compared to a control group according to blood transfusion rate, mortality rate and revision surgery rate. The fractures were detected during the surgery in twenty cases (80%);for the five remaining cases the fracture was only detected in the postoperative radiology. For those detected during the surgery, the two most common manouvers in which the fracture occurred was hip reduction (10 cases) and prosthesis introduction (7 cases). The blood transfusion rate, first-month mortality rate and revision surgery rate showed no statistical difference between the two groups (p = 0.3). In the present series, most of IPFF during Austin-Moore hemiarthroplasty implantation, occurred during arthroplasty reduction. Difficulties during this step should lead the surgeon to reconsider if technical mistakes are present and can be solved. However, if fracture occurs, adequate treatment of IPFF should provide satisfactory results without increasing blood transfusi

关键词： Hip Hemiarthroplasty Intraoperative Fracture Complication

Towards a scientific rationale for traditional properties of Chinese medicinal plants: “natures” and “flavors”

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Chinese Herbal Medicines 2019年第3期11卷 258-266页

作者： Li-ping Li Ben-gang Zhang Zhao Zhang Xiao-j.n Li Guo-ping Wang Hai-long Song Cong-zhao Fan Yang-ming j.ang Tuo Wang Hui-hui Zhao Wei-hong Cui j.ang-shan Lai Xiu-lian Chi Xue-ping Wei Chong-ming Wu Yao-dong Qi Hai-tao Liu Pei-gen Xiao Eimear nic Lughadha Christine j.Leon Institute of Remote Sensing and Digital Earth Chinese Academy of SciencesBeijing100101China Institute of Medicinal Plant Development Chinese Academy of Medical SciencesPeking Union Medical CollegeBeijing100193China Xinj.ang Institute of Chinese and Ethnic Medicine Urumqi830002China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing100093China National Resource Center for Chinese Materia Medica China Academy of Chinese Medical SciencesState Key Laboratory Breeding Base of Dao-di HerbsBeijing100700China Conservation Science Department Royal Botanic GardensKewRichmondSurreyTW93AEUK Collections Department Royal Botanic GardensKewRichmondSurreyTW93AEUK

Obj.ctive: According to theory of Chinese medicine property, the ecological environment shapes properties(natures and flavors) of Chinese materia medica(CMM) and there are close relationships between certain natures and flavors. However, to date these observations have not been validated scientifically in the context of the whole flora of a region. The present study aims to address this ***: We collected geographical distributions of 3637 vascular plant species native to the Xinj.ang region of northwest China, of which around 812 are medicinal plants. The CMM property characters of these medicinal plants were also collected. All medicinal plants were then analyzed in the occurrence of their natures(cold, cool, neutral, warm, and hot) and flavors(sweet, bitter, sour, salty, and pungent). Possible correlations between these properties and environmental factors, notably climate, as well as correlations with plant species richness of the wider native flora of Xinj.ang were then investigated using permutation test and ***: Cold species(38.5%) were more numerous than warm(21.0%) and neutral(22.3%), while bitter species(43.3%) were more numerous than pungent(25.6%), sweet(22.4%) and sour(6.7%) ones. Species with bitter flavor were most commonly also cold(48.6%) in nature, sour flavor usually coincided with cold(44.2%) or cool nature(26.0%), whereas pungent or sweet species tended to be warm(34.4%, 28.4%) or neutral(27.8%, 28.4%). The percentages of species of cold/cool nature, bitter flavor were higher in mountainous regions, and the percentages of warm/neutral and pungent/sweet/sour were higher in basins. The percentages of species of cold/cool, bitter were positively correlated with actual evapotranspiration(AET),and also plant species richness but had a bell-shaped relationship with potential evapotranspiration(PET),whereas the inverse situation was shown for warm/neutral and pungent/sweet/sour ***: Analysis of the data in Xinj.ang

关键词： flavor nature Chinese materia medica theory of Chinese medicine property Xinj.ang region

Simultaneous pars plana vitrectomy,panretinal photocoagulation,cryotherapy,and Ahmed valve implantation for neovascular glaucoma

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International j.urnal of Ophthalmology(English edition) 2021年第9期14卷 1396-1401页

作者： Carolina Bernal-Morales Marina Dotti-Boada Alvaro Olate-Perez Manuel j.Navarro-Angulo Laura Pelegrín Marc Figueras-Roca Institut Clínic d’Oftalmologia(ICOF) Hospital ClínicBarcelona 08028Spain August Pi i Sunyer Biomedical Research Institute(IDIBAPS) Barcelona 08028Spain

AIM:To describe and evaluate the efficacy of Ahmed glaucoma valve implantation(AGV)combined with pars plana vitrectomy(PPV)in a single surgical act for the treatment of advanced neovascular glaucoma(NVG).METHODS:Retrospective observational case series included 51 eyes from 50 patients with severe NVG treated with PPV,AGV,and panretinal photocoagulation and/or cryotherapy in a single surgical act during a 13-year period(2005-2018).Preoperative,intraoperative and postoperative data at day 1 and months 1,3,6,21,and 24 were systematically *** of surgical success was stablished at IOP between 6 and 21 mm Hg with or without topical ***:Main indications for surgery were NVG secondary to proliferative diabetic retinopathy(39.2%)and central retinal vein occlusion(37.3%).Mean(±SD)preoperative IOP was 42.0±11.2 mm Hg decreasing to 15.5±7.1 mm Hg at 12 mo and 15.8±9.1 mm Hg at 24 mo of follow *** incidence of success of IOP control was 76.0%at first postoperative month,reaching 88.3%at 6 *** of successful IOP control at long term was 74.4%at 12 mo and 71.4%at 24 *** evisceration for unsuccessful NVG management was required in 1 case(2.0%).CONCLUSION:Combination of AGV implantation and PPV in a single act may be a suitable option for severe forms of NVG in a case-by-case basis for effective IOP control and a complete panretinal photocoagulation.

关键词： neovascular glaucoma Ahmed valve pars plana vitrectomy panretinal photocoagulation cryotherapy

Gyrokinetic simulation of low-n Alfvénic modes in tokamak HL-2A plasmas

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Chinese Physics B 2023年第2期32卷 358-365页

作者：林文浩李继全 j.Garcia S Mazzi Southwestern Institute of Physics Chengdu 610041China CEA IRFM13108Saint-Paul-lez-DuranceFrance EPFL Swiss Plasma CenterLausanneSwitzerland

The turbulence characteristics of plasmas with internal transport barriers in the HL-2A tokamak are analyzed by means of linear gyrokinetic simulations. It is found that turbulence is dominated by the ion temperature gradient(ITG)mode together with large-scale modes characterized by high-frequency electromagnetic fluctuation, which are destabilized by the steep ion temperature gradient in the weak magnetic shear regime. Comparison with solutions of analytical dispersion relations shows that their linear features match well with the beta-induced Alfvén eigenmode branch of the shear Alfvénic spectrum. It is further clarified that the large population of fast ions in these plasmas plays a stabilization role through the dilution mechanism in high-n ITG mode regimes.

关键词： low-n Alfvénic modes fast ions gyrokinetic simulation tokamak

Spin-polarized electron beam generation in the colliding-pulse inj.ction scheme

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Matter and Radiation at Extremes 2023年第6期8卷 49-62页

作者： Zheng Gong Michael j.Quin Simon Bohlen Christoph HKeitel Kristj.n Põder Matteo Tamburini Max-Planck-Institut für Kernphysik Saupfercheckweg 169117 HeidelbergGermany Deutsches Elektronen-Synchrotron DESY Notkestr.8522607 HamburgGermany

Employing colliding-pulse inj.ction has been shown to enable the generation of high-quality electron beams from laser-plasma ***,by using test particle simulations,Hamiltonian analysis,and multidimensional particle-in-cell simulations,we lay the theoretical framework for spin-polarized electron beam generation in the colliding-pulse inj.ction ***,we show that this scheme enables the production of quasi-monoenergetic electron beams in excess of 80%polarization and tens of pC charge with commercial 10-TW-class laser systems.

关键词： polarized scheme enable