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265篇 您的检索式:作者名="Hoefs"
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1Two-fluid modeling of Geldart A particles in gas-fluidized beds显示文摘We have investigated the effect of cohesion and drag models on the bed hydrodynamics of Geldart A particles based on the two-fluid (TF) model. For a high gas velocity U0 = 0.03 m/s, we found a transition from the homogeneous fluidization to bubbling fluidization with an increase of the coefficient C1, which is used to account for the contribution of cohesion to the excess compressibility. Thus cohesion can play a role in the bed expansion of Geldart A particles. Apart from cohesion, we have also investigated the influence of the drag models. When using the Wen and Yu drag correlation with an exponent n = 4.65, we find an under-prediction of the bed expansion at low gas velocities (U0 = 0.009 m/s). When using a larger exponent (n = 9.6), as reported in experimental studies of gas-fluidization, a much better agreement with the experimental bed expansion is obtained. These findings suggest that at low gas velocity, a scale-down of the commonly used drag model is required. On the other hand, a scale-up of the commonly used drag model is necessary at high gas velocity (U0 = 0.2 and 0.06 m/s). We therefore conclude that scaling the drag force represent only an ad hoc way of repairing the deficiencies of the TF model, and that a far more detailed study is required into the origin of the failure of the TF model for simulating fluidized beds of fine powders.M.A. van der Hoef J.A.M. Kuipers 2008Particuology2008,6,6:16
2南苏鲁超高压榴辉岩中罕见的原生高密度盐水溶液包裹体显示文摘在南苏鲁超高压变质带发现了原生高密度流体包裹体. 这种包裹体在超高压榴辉岩的石榴石中呈孤立和小群分布, 冷冻法确定包裹体的低共熔温度≤-52℃, 在重复冷冻-升温的特定阶段, 液相包裹体中出现气泡, 测得液-气均一温度≤-12.5℃, 由此得到流体成分属CaCl2-NaCl-H2O体系, 流体密度为1.27 g/cm3, 在相当于榴辉岩相峰期温度下的压力约为2.4 GPa, 接近超高压变质条件. 这类包裹体在榴辉岩的折返过程中与寄主矿物发生反应, 形成含水硅酸盐矿物, 并使其密度降低, 转变成气液多相包裹体.沈昆 张泽明 A. M. van den Kerkhof 肖益林 许志琴 J. Hoefs 2003科学通报2003,48,10:10
3超高压变质作用过程中的流体岩石相互作用——中国大陆科学钻探工程主孔(0~2050m)岩心的氧同位素证据显示文摘中国大陆科学钻探工程主孔位于苏鲁超高压变质带南部的东海地区。该钻孔 0~ 2 0 5 0m井段钻遇的岩石主要是榴辉岩、正片麻岩、副片麻岩和石榴石橄榄岩。激光原位氧同位素研究表明 ,变质矿物的δ18O值具有显著的不均一性 ,从 - 6 .8‰变化至 + 7.5‰。空间上看 ,从近地表至 10 0 0m深度δ18O值逐渐降低 ,向更深处又逐渐升高。位于钻孔 110 0~ 16 0 0m深度之间的正片麻岩是新元古代花岗岩体 ,该岩体的侵入为表壳岩与低氧同位素大气降水之间的水岩交换作用提供了热源 ,并导致岩体附近的围岩发生了最强烈的水岩蚀变 ,因此具有极低的氧同位素值。研究还显示 ,在厘米尺度内 ,大多数超高压变质矿物之间具有平衡的氧同位素组成 ,所获得的超高压峰期变质温度为 70 0~ 882℃ ,与矿物之间的主元素交换温度计获得的结果基本相同。超高压变形与变质分异、高压退变质作用及其伴生的局部流体活动可能是造成超高压变质矿物氧同位素不平衡的主要原因。研究进一步证明 ,超高压变质岩原岩的异常低氧同位素特征在大陆板块的俯冲与折返过程中得以较好保存 ,在超高压变质前期、同期和后期均没有大规模的透入性流体活动发生。与围岩呈构造接触关系的石榴石橄榄岩具有正常地幔岩的氧同位素成分 。张泽明 肖益林 Jochen HOEFS 高勇军 2004岩石矿物学杂志2004,23,4:6
4COMPUTATIONAL FLUID DYNAMICS FOR DENSE GAS-SOLID FLUIDIZED BEDS: A MULTI-SCALE MODELING STRATEGY显示文摘Dense gas-particle flows are encountered in a variety of industrially important processes for large scale production of fuels, fertilizers and base chemicals. The scale-up of these processes is often problematic and is related to the intrinsic complexities of these flows which are unfortunately not yet fully understood despite significant efforts made in both academic and industrial research laboratories. In dense gas-particle flows both (effective) fluid-particle and (dissipative) particle-particle interactions need to be accounted for because these phenomena to a large extent govern the prevailing flow phenomena, i.e. the formation and evolution of heterogeneous structures. These structures have significant impact on the quality of the gas-solid contact and as a direct consequence thereof strongly affect the performance of the process. Due to the inherent complexity of dense gas-particles flows, we have adopted a multi-scale modeling approach in which both fluid-particle and particle-particle interactions can be properly accounted for. The idea is essentially that fundamental models, taking into account the relevant details of fluid-particle (lattice Boltzmann model) and particle-particle (discrete particle model) interactions, are used to develop closure laws to feed continuum models which can be used to compute the flow structures on a much larger (industrial) scale. Our multi-scale approach (see Fig. 1 ) involves the lattice Boltzmann model, the discrete particle model, the continuum model based on the kinetic theory of granular flow and the discrete bubble model. In this paper we give an overview of the multi-scale modeling strategy, accompanied by illustrative computational results for bubble formation. In addition, areas which need substantial further attention will be highlighted.M. A. van der Hoef M. van Sint Annaland J. A. M. Kuipers 2005China Particuology2005,3,1:4
5Gas–solid interaction force from direct numerical simulation (DNS) of binary systems with extreme diameter ratios显示文摘Fluid-particle systems as commonly encountered in chemical, metallurgical and petroleum industries are mostly polydisperse in nature. However, the relations used to describe fluid-particle interactions are originally derived from monodisperse systems, with ad hoc modifications to account for polydispersity. In previous work it was shown that for bidisperse systems with moderate diameter ratios of 1:2 to 1:4, this approach leads to discrepancies, and a correction factor is needed. In this work we demonstrate that this correction factor also holds for more extreme diameter ratios of 1:5, 1:7 and 1:10, although the force on the large particles is slightly overestimated when using the correction factor. The main origin of the correction is that the void surrounding the large particles becomes less in case of a bidisperse mixture, as compared to a monodisperse system with the same volume fraction. We further investigated this discrepancy by calculating the volume per particle by means of Voronoi tessellation.S. Sarkar S.H.L. Kriebitzsch M.A. van der Hoef J.A.M. Kuipers 2009Particuology2009,7,4:2
6Des-γ-Carboxy Prothrombin and α-Fetoprotein as Biomarkers for the Early Detection of Hepatocellular Carcinoma显示文摘Anna S. Lok Richard K. Sterling James E. Everhart Elizabeth C. Wright John C. Hoefs Adrian M. Di Bisceglie Timothy R. Morgan Hae–Young Kim William M. Lee Herbert L. Bonkovsky Jules L. Dienstag 2010Gastroenterology2010,,2:2
7Review of discrete particle modeling of fluidized beds 显示文摘DEEN N G van SINT ANNALAND M van der HOEF M A 2007Chemical Engineering Science2007,62,1820:1
8Coronary pressure-flow relations as basis for the understanding of coronary physiology显示文摘Tim P. van de Hoef Froukje Nolte M. Cristina Rolandi Jan J. Piek Jeroen P.H.M. van den Wijngaard Jos A.E. Spaan Maria Siebes 2011Journal of Molecular and Cellular Cardiology2011,,:1
9Homo-and heterotetrameric architecture of the epithelial Ca^2+ channels TRPV5 and TRPV6显示文摘Hoenderop J G Voets T Hoefs S 2003Embo J2003,22,4:1
10Primary neuroendocrine tumors of the liver: MRI features in two cases显示文摘Van der Hoef M Crook DW Marincek B 2004Abdom Imaging2004,29,2:1
11Oxygen isotope heterogeneity of the mantle deduced from global 18O systematics of basalts from different geotectonic settings显示文摘Russell S. Harmon Jochen Hoefs 1995Contributions to Mineralogy and Petrology1995,,1:1
12Rate of progression of hepatic fibrosis in patients with chronic hepatitis C:results from the HALT-C Trial显示文摘Hoefs JC Shiffman ML Goodman ZD 0,,:1
13Post-colli- sional granitoids from the Dabieorogen: New evidence for partial melting of a thickened continental crust显示文摘He Yongsheng Li Shuguang Hoefs Jochen 2011Geochimica et Cos- mochimica Acta2011,75,:1
14Impaired coronary autoregulation is associated with long-term fatal events in patients with stable coronary artery disease显示文摘VAN DE HOEF T P BAX M DAMMAN P 2013Circ Cardiovasc Interv2013,6,:1
15Genomic typing of Listeria monocytogenes strains by automated laser fluorescence analysis of amplified fraonent length polymorphism fingerprint patterns显示文摘AARTS H J HAKEMULDER L E VAN HOEF A M 1999lnt J Food Microbiol1999,43,12:1
16CFD study of the minimum bubbling velocity of Geldart A particles in gas- fluidized beds显示文摘Wang J Van der Hoef M A Kuipers J A M 2010Chemieal Engineering Science2010,65,12:1
17Fluid history of UHP metamorphism in Dabie Shan, China: a fluid inclusion and oxygen isotope study on the coesite-bearing eclogite from Bixiling显示文摘Yilin Xiao Jochen Hoefs Alfons M. van den Kerkhof Jens Fiebig Yongfei Zheng 2000Contributions to Mineralogy and Petrology2000,,1:1
18Sr-Nd-Pb iso- topic compositions of Early Cretaceous granitoids from the Dabieo- rogen: Constraints on the recycled lower continental crust 显示文摘He Yongsheng Li Shuguang Hoefs Jochen 2013Lithos2013,,:1
19Carbon and oxygen isotopic covariations in hydrothermal calcites: Theoretical modeling on mixing processes and application to Pb-Zn deposits in the Harz Mountains, Germany显示文摘Zheng Y F Hoefs J 1993Mineral Deposita1993,28,2:1
20Evalu- ation of a self - management programmed for congestive heart failure patients : design of a randomized controlled trial 显示文摘Smeulders ES van Haastregt JC van Hoef EF 2006BMC Health Serv Res2006,6,:1
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