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分层空调下高大焊接厂房双扩散对流

中南大学学报（自然科学版） 2016年第4期47卷 1447-1458页

作者：王沨枫刘志强 christoph van treeck 王汉青唐文武寇广孝中南大学能源科学与工程学院湖南长沙410083 Faculty of Civil Engineering RWTH Aachen Universityaachen52074 湖南工业大学土木工程学院湖南株洲412008

利用计算流体力学技术并结合现场实测分析分层空调系统设计关键参数如送风量、送风速度及分层高度等对某高大焊接厂房室内双扩散对流及通风空调效果和效率的影响。同时,还分析高大焊接厂房分层通风空调系统的适用性。研究结果表明：厂... 详细信息

利用计算流体力学技术并结合现场实测分析分层空调系统设计关键参数如送风量、送风速度及分层高度等对某高大焊接厂房室内双扩散对流及通风空调效果和效率的影响。同时,还分析高大焊接厂房分层通风空调系统的适用性。研究结果表明：厂房下部风口排风比宜取为75%;送风量安全系数Ks可取为2.5~4.0;提高送风速度、下部排风口底部安装高度及降低分层高度均无法有效提升厂房通风空调效果和效率;各工况下厂房室内流体运动、热、质输运为双扩散混合或自然对流,焊接表面Nusselt数及Sherwood数基本不变;当厂房焊接烟尘散发量大时,分层空调节能性是一大挑战。将焊接热和污染源简化为稳态散发的条缝形热和污染面源,室内焊接烟尘质量浓度模拟值与实测值较好地吻合,相对误差为11.2%。

关键词：计算流体力学现场实测分层空调双扩散对流

Self-assembled formation of long, thin, and uncoalesced GaN nanowires on crystalline TiN films

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Nano Research 2018年第1期11卷 565-576页

作者： David van treeck Gabriele Calabrese Jelle J. W. Goertz Vladimir M. Kaganer Oliver Brandt Sergio Fernandez-Garrido, Lutz Geelhaar PauI-Drude-lnstitut f~r Festk6rperelektronik Leibniz-lnstitut im Forschungsverbund Berlin e.V. Hausvogteiplatz 5-7 I 0117 Berlin Germany

We investigate in detail the self-assembled nucleation and growth of vertically oriented GaN nanowires by molecular beam epitaxy on crystalline TiN films. We demonstrate that this type of substrate allows for the growth of long and thin GaN nanowires that do not suffer from coalescence, a problem common to the growth on Si and other substrates. Only beyond a certain nanowire length that depends on the nanowire density and exceeds here 1.5 bun, coalescence takes place by bundling, i.e. the same process as on Si. By analyzing the nearest neighbor distance distribution, we identify the diffusion-induced repulsion of neighboring nanowires as the main mechanism limiting nanowire density during nucleation on TiN. Since on Si the final density is determined by shadowing of the impinging molecular beams by existing nanowires, it is the difference in adatom surface diffusion that enables the formation of nanowire ensembles with reduced density on TiN. These nanowire ensembles combine properties that make them a promising basis for the growth of core-shell heterostructures.

关键词： nanocolumn gallium nitride nucleation metal substrate coalescence core-shell

Hyperactive learning for data-driven interatomic potentials

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npj Computational Materials 2023年第1期9卷 599-612页

作者： Cas van der Oord Matthias Sachs Dávid Péter Kovács christoph Ortner Gábor Csányi University of Cambridge Cambridge CB21PZUK University of Birmingham Birmingham B152TTUK University of British Columbia VancouverBC V6T 1Z2Canada

Data-driven interatomic potentials have emerged as a powerful tool for approximating ab initio potential energy *** most time-consuming step in creating these interatomic potentials is typically the generation of a suitable training *** aid this process hyperactive learning(HAL),an accelerated active learning scheme,is presented as a method for rapid automated training database *** adds a biasing term to a physically motivated sampler(*** dynamics)driving atomic structures towards uncertainty in turn generating unseen or valuable training *** proposed HAL framework is used to develop atomic cluster expansion(ACE)interatomic potentials for the AlSi10 alloy and polyethylene glycol(PEG)polymer starting from roughly a dozen initial *** HAL generated ACE potentials are shown to be able to determine macroscopic properties,such as melting temperature and density,with close to experimental accuracy.

关键词： starting generating consuming

Megacolon in adulthood after surgical treatment of Hirschsprung's disease in early childhood

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World Journal of Gastroenterology 2005年第36期11卷 5742-5745页

作者： christoph R.Werner Gisela Stoltenburg-Didinger Henning Weidemann christoph Benckert Marco Schmidtmann Ivo R.van der Voort Viola Andresen Burghard F.Klapp Peter Neuhaus Bertram Wiedenmann Hubert Mnnikes Department of Medicine Division of Hepatology and Gastroenterology Charite Campus Virchow-Klinikum Universitatsmedizin Berlin Augustenburger Platz 1 13353 Berlin Germany Department of Neuropathology Charité Campus Virchow-Klinikum Universittsmedizin Berlin Augustenburger Platz 1 13353 Berlin Germany Department of General Visceral and Transplantation Surgery Charité Campus Virchow-Klinikum Universittsmedizin Berlin Augustenburger Platz 1 13353 Berlin Germany Department of Medicine Division of Psychosomatic Medicine and Psychotherapy Charité Campus Virchow-Klinikum Universittsmedizin Berlin Augustenburger Platz 1 13353 Berlin Germany Department of Medicine Division of Hepatology and Gastroenterology Charité Campus Virchow-Klinikum Universittsmedizin Berlin Augustenburger Platz 113353 Berlin Germany

Hirschsprung＇s disease （HD） is a disorder associated with congenital malformation of the enteric nervous system with segmental aganglionosis. Prevailing therapy includes a resection of the affected part of the bowel, However, patients often do not obtain complete functional improvement after surgical treatment. We present the case of a 25-year-old woman who had surgical treatment of lid in early childhood. After that procedure she had clinical features of constipation for years in the end, passing of stool once a week, requiring laxatives and enemas. We diagnosed an incomplete resection of the aganglionic bowel via rectal biopsy and resected the remaining aganglionic segment. Two months after surgery the patient＇s bowel function improved to a frequency of 1-4 stools per day. We conclude that regular follow-up is required to identify lid patients with persistent alterations of bowel function after surgery. In patients presenting with constipation, recognition of a remaining aganglionic segment or other alterations of the enteric nervous system should be aimed at in an early stage. 2005 The WJG Press and Elsevier Inc. All rights reserved

关键词： Hirschsprung's disease Megacolon Surgicaltreatment Constipation

Performant implementation of the atomic cluster expansion(PACE)and application to copper and silicon

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npj Computational Materials 2021年第1期7卷 878-889页

作者： Yury Lysogorskiy Cas van der Oord Anton Bochkarev Sarath Menon Matteo Rinaldi Thomas Hammerschmidt Matous Mrovec Aidan Thompson Gábor Csányi christoph Ortner Ralf Drautz ICAMS Ruhr-Universität BochumBochumGermany Engineering Laboratory University of CambridgeCambridgeUK Center for Computing Research Sandia National LaboratoriesAlbuquerqueNMUSA Department of Mathematics University of British ColumbiaVancouverBCCanada

The atomic cluster expansion is a general polynomial expansion of the atomic energy in multi-atom basis *** we implement the atomic cluster expansion in the performant C++code PACE that is suitable for use in large-scale atomistic *** briefly review the atomic cluster expansion and give detailed expressions for energies and forces as well as efficient algorithms for their *** demonstrate that the atomic cluster expansion as implemented in PACE shifts a previously established Pareto front for machine learning interatomic potentials toward faster and more accurate ***,general purpose parameterizations are presented for copper and silicon and evaluated in *** show that the Cu and Si potentials significantly improve on the best available potentials for highly accurate large-scale atomistic simulations.

关键词： functions expansion cluster

2050年前土地利用变化的轨迹:基于全球农业经济模式比较的视角

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世界农业 2014年第10期 119-127页

作者： christoph Schmitz Hans van Meijl 赵冉不详北京中绿田源农业发展有限公司

改变农业土地的利用对环境服务有重要意义。本文第一次提出了把全球农业经济模式与相应的人口、GDP和生物物理收益率进行全面的综合比较。通过比较提出,1在不同的社会经济和气候变化中,将有多少农田会被利用。2不同的模式结果又该如何... 详细信息

改变农业土地的利用对环境服务有重要意义。本文第一次提出了把全球农业经济模式与相应的人口、GDP和生物物理收益率进行全面的综合比较。通过比较提出,1在不同的社会经济和气候变化中,将有多少农田会被利用。2不同的模式结果又该如何来解释？这个比较包括4个部分和6个如何模拟潜在的可种用土地的供应和金额的不同的一般均衡模式。笔者分析了2种不同的社会经济情景和3个气候情景（恒定的气候）。大多数模式（70%）反映从2005—2050年（在恒定的气候条件下）耕地将同比增长10%-25%,而只有一个模式反映是减少的。从一些模式中可以看出,牧场的扩大,减少了自然植被的进一步恢复。通过所有的模式,可以看出,大部分的耕地扩张发生在南美洲和非洲撒哈拉以南地区。通常,模式结果的最大差异与土地扩张的不同成本、内生生产力的响应和潜在耕地的假设有关。

关键词：土地利用变化模型比对土地利用模式用地扩张

Endoscopic ultrasound elastography for evaluation of lymph nodes and pancreatic masses:A multicenter study

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World Journal of Gastroenterology 2009年第13期15卷 1587-1593页

作者： Marc Giovannini Botelberge Thomas Bories Erwan Pesenti Christian Caillol Fabrice Esterni Benjamin Monges Geneviève Arcidiacono Paolo Deprez Pierre Yeung Robert Schimdt Walter Schrader Hanz Szymanski Carl Dietrich christoph Eisendrath Pierre van Laethem Jean-Luc Devière Jacques Vilmann Peter Saftoiu Andrian Endoscopy Unit Paoli-Calmettes Institute Department of Pathology Paoli-Calmettes Institute Endosonography Unit Gastroenterology and Gastrointestinal Endoscopy UnitSan Raffaele Hospital Division of Gastroenterology University Hospital Saint-Luc Department of MedicineⅠ University Hospital Department of Internal Medicine 2 Caritas-KrankenhausBad Mergentheim Division of Gastroenterology Erasme Hospital Department of Surgical Gastroenterology Gentofte University Hospital

AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph ***:A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass(n=121) or lymph node(n=101).The classification as benign or malignant,based on the real time elastography pattern,was compared with the classif ication based on the B-mode EUS images and with the fi nal diagnosis obtained by EUS-guided fi ne needle aspiration(EUS-FNA) and/or by surgical *** interobserver study was ***:The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%,respectively,compared to 92.3% and 68.9%,respectively,for the conventional B-mode *** sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%,respectively,compared to 78.6% and 50.0%,respectively,for the B-mode *** kappa coefficient was 0.785 for the pancreatic masses and 0.657 for the lymph ***:EUS elastography is superior compared to conventional B-mode imaging and appears to be able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivity,specificity and *** might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes.

关键词： Endoscopic ultrasound Elasticity coefficient Elastography Pancreatic mass Lymph node

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公司风险管理法律原则的风险

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商法界论集 2022年第2期 151-179页

作者： christoph van der Elst 沈朝晖李凌霜清华大学法学院

公司治理准则与公司法包含内部控制与风险管理的条款。首先,本文分析西欧五国这些相关条款的前沿状况。五国范围内,监管框架的模式不是单一的,它跨越了德国Frühwarnsystem模式、法国董事会主席的内部控制报告、荷兰董事会的内部控制陈... 详细信息

公司治理准则与公司法包含内部控制与风险管理的条款。首先,本文分析西欧五国这些相关条款的前沿状况。五国范围内,监管框架的模式不是单一的,它跨越了德国Frühwarnsystem模式、法国董事会主席的内部控制报告、荷兰董事会的内部控制陈述、欧盟公司治理陈述与英国的稳健风险管理原则。其次,本文分析在过去的十年,房地产投资基金的样本公司是如何把内部控制与风险管理的规则与原则落实到实践中的。分析表明:尽管风险评估,特别是非财务风险的影响评估,与控制行为仍然有很大的提升空间,但是,风险的识别、财务风险的管理与对风险的反应已经发展到一个高级阶段。这些证据表明,监管与立法驱动了风险管理的实践。有一些内部控制的国别特色消弭了,出现融合迹象。最后一节讨论实证研究的法律政策含义:在监管不断完善与公司创新实践的背景下,出现了新的风险。第一,法律的强制要求,加上公司完全遵守最佳实践的渴望,创造了一种张力:是介于(1)风险管理框架的基本假设——(仅仅)提供基本的保障与(2)管理、明显控制所有(实质)风险的(报告的)前沿状况二者之间的张力。第二,存在一种两极分化的风险:在相关公司机关的风险管理责任分配方面,有很大的进展;但在法律其他领域,特别是责任机制领域,则止步不前。

关键词：风险管理内部控制公司治理公司法公司实践公司报告

Validation of a discrete element model using magnetic resonance measurements

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Particuology 2009年第4期7卷 297-306页

作者： christoph R.Müller Stuart A.Scott Daniel J.Holland Belinda C.Clarke Andrew J.Sederman John S.Dennis Lynn F.Gladden Department of Chemical Engineering and Biotechnology University of CambridgePembroke StreetCambridge CB2 3RAUnited Kingdom

The discrete element model （DEM） is a very promising modelling strategy for two-phase granular systems. However, owing to a lack of experimental measurements, validation of numerical simulations of two-phase granular systems is still an important issue. In this study, a small two-dimensional gas- fluidized bed was simulated using a discrete element model. The dimensions of the simulated bed were 44mm × 10mm × 120 mm and the fluidized particles had a diameter dp = 1.2 mm and density ρp = 1000 kg/m^3. The comparison between DEM simulations and experiments are performed on the basis of time-averaged voidage maps. The drag-law of Beetstra et al. [Beetstra, R., van der Hoef, M.A., ＆ Kuipers,J. A. M. （2007b）. Drag force of intermediate Reynolds number flow past mono- and bidispersed arrays of spheres. AIChE Journal, 53,489-501 ] seems to give the best results. The simulations are fairly insensitive to the coefficient of restitution and the coefficient of friction as long as some route of energy dissipation during particle-particle and particle-wall contact is provided. Changing the boundary condition of the gas phase at the side-walls from zero-slip to full-slip does not affect the simulation results. Care is to be taken that the cell sizes are chosen so that a reasonable number of particles can be found in a fluid cell.

关键词： Discrete element modelling Magnetic resonance imaging Voidage Gas-fluidized beds