The Experts below are selected from a list of 10698 Experts worldwide ranked by ideXlab platform
Lei Jiang - One of the best experts on this subject based on the ideXlab platform.
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photoelectric cooperative patterning of liquid permeation on the micro nano hierarchically Structured Mesh film with low adhesion
Nanoscale, 2014Co-Authors: Zhenyan Guo, Xi Zheng, Dongliang Tian, Yanlin Song, Jin Zhai, Xiaofang Zhang, Xiaolin Wang, S X Dou, Lei JiangAbstract:Stimuli-responsive surface wettability has been intensively studied, especially wettability controlled by photoelectric cooperation, which appears to be a trend for more effective surface wetting. In this field, the patterning of controllable surface wettability is still a challenge in the application of liquid-printing techniques because of the high adhesion and high responsive voltage, as well as low mechanical strength, of the substrate. Herein, we have demonstrated the patterning of liquid permeation controlled by photoelectric cooperative wetting on the micro/nano hierarchically Structured ZnO Mesh film. The special micro/nano hierarchically Structured ZnO Mesh is beneficial for lowering adhesion force on the Mesh surface than those of the TiO2/AAO nanopore array films previously reported for the discontinuous tri-phase contact line, in addition to precisely controlled microscale liquid movement with considerably lower threshold voltage for the hierarchical structure. Moreover, the stainless-steel Mesh with different pore sizes as a substrate behaves with higher mechanical strength and lower cost, compared with the anodized Ti Mesh. Thus, this work is promising for accelerating the development of patterned liquid permeation and extending the application of micro/nanofluidic system and micronanoelectronic technology.
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microscale and nanoscale hierarchical Structured Mesh films with superhydrophobic and superoleophilic properties induced by long chain fatty acids
Nanotechnology, 2007Co-Authors: Shutao Wang, Yanlin Song, Lei JiangAbstract:Inspired by the lotus effect, we fabricate new microscale and nanoscale hierarchical Structured copper Mesh films by a simple electrochemical deposition. After modification of the long-chain fatty acid monolayer, these films show superhydrophobic and superoleophilic properties, which could be used for the effective separation of oil and water. The length of the fatty acid chain strongly influences the surface wettability of as-prepared films. It is confirmed that the cooperative effect of the hierarchical structure of the copper film and the nature of the long-chain fatty acid contribute to this unique surface wettability.
Patrick Tamain - One of the best experts on this subject based on the ideXlab platform.
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A penalization technique to model plasma facing components in a tokamak ă with temperature variations
Journal of Computational Physics, 2014Co-Authors: A Paredes, Philippe Ghendrih, Frédéric Schwander, Hugo Bufferand, Guido Ciraolo, Eric Serre, Patrick TamainAbstract:To properly address turbulent transport in the edge plasma region of a ă tokamak, it is mandatory to describe the particle and heat outflow on ă wall components, using an accurate representation of the wall geometry. ă This is challenging for many plasma transport codes, which use a ă Structured Mesh with one coordinate aligned with magnetic surfaces. We ă propose here a penalization technique that allows modeling of particle ă and heat transport using such Structured Mesh, while also accounting for ă geometrically complex plasma-facing components. Solid obstacles are ă considered as particle and momentum sinks whereas ionic and electronic ă temperature gradients are imposed on both sides of the obstacles along ă the magnetic field direction using delta functions (Dirac). Solutions ă exhibit plasma velocities (M = 1) and temperatures fluxes at the ă plasma-wall boundaries that match with boundary conditions usually ă implemented in fluid codes. Grid convergence and error estimates are ă found to be in agreement with theoretical results obtained for neutral ă fluid conservation equations. The capability of the penalization ă technique is illustrated by introducing the non-collisional plasma ă region expected by the kinetic theory in the immediate vicinity of the ă interface, that is impossible when considering fluid boundary ă conditions. Axisymmetric numerical simulations show the efficiency of ă the method to investigate the large-scale transport at the plasma edge ă including the separatrix and in realistic complex geometries while ă keeping a simple Structured grid. (C) 2014 Elsevier Inc. All rights ă reserved.
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A penalization technique to model plasma facing components in a tokamak with temperature variations
Journal of Computational Physics, 2014Co-Authors: A Paredes, Philippe Ghendrih, Frédéric Schwander, Hugo Bufferand, Guido Ciraolo, Eric Serre, Patrick TamainAbstract:To properly address turbulent transport in the edge plasma region of a tokamak, it is mandatory to describe the particle and heat outflow on wall components, using an accurate representation of the wall geometry. This is challenging for many plasma transport codes, which use a Structured Mesh with one coordinate aligned with magnetic surfaces. We propose here a penalization technique that allows modelingof particle and heat transport using such Structured Mesh, while also accounting for geometrically complex plasma-facing components. Solid obstacles are considered as particle and momentum sinks whereas ionic and electronic temperature gradients are imposed on both sides of the obstacles along the magnetic field direction using delta functions (Dirac). Solutions exhibit plasma velocities (M=1) and temperatures fluxes at the plasma–wall boundaries that match with boundary conditions usually implemented in fluid codes. Grid convergence and error estimates are found to be in agreement with theoretical results obtained for neutral fluid conservation equations. The capability of the penalization technique is illustrated by introducing the non-collisional plasma region expected by the kinetic theory in the immediate vicinity of the interface, that is impossible when considering fluid boundary conditions. Axisymmetric numerical simulations show the efficiency of the method to investigate the large-scale transport at the plasma edge including the separatrix and in realistic complex geometries while keeping a simple Structured grid.
Hansjoachim Wuensche - One of the best experts on this subject based on the ideXlab platform.
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fast multi pass 3d point segmentation based on a Structured Mesh graph for ground vehicles
IEEE Intelligent Vehicles Symposium, 2018Co-Authors: Patrick Burger, Hansjoachim WuenscheAbstract:Point-cloud segmentation of 3D LiDAR scans is an important preprocessing task for autonomous vehicles in on-road and especially in off-road scenarios. Clustering point measurements with the same properties into multiple homogeneous regions is a challenging task due to an uneven sampling density and lack of explicit structural information. This paper presents a novel technique to achieve a robust and fast point-cloud segmentation using the characteristic intrinsic sensor pattern. This pattern is characterized by the mounting position of each laser diode. A Structured Mesh graph is created by taking the beam calibration and the chronology of incoming data packets into account. The proposed graph-based, multi-pass point segmentation algorithm compares this pattern with a flat-world model to detect discontinuities and to set label attributes such as obstacle or free space for each vertex. Furthermore, we directly detect missing measurements and therefore generate artificial vertices considering the laser beam intrinsics. Finally, a region-growing algorithm is applied in order to obtain cohesive objects. Experimental results show that we achieve a reliable overall performance and a good trade-off between segmentation quality and runtime of 15ms in rough terrain as well as suburban areas.
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Intelligent Vehicles Symposium - Fast Multi-Pass 3D Point Segmentation Based on a Structured Mesh Graph for Ground Vehicles
2018 IEEE Intelligent Vehicles Symposium (IV), 2018Co-Authors: Patrick Burger, Hansjoachim WuenscheAbstract:Point-cloud segmentation of 3D LiDAR scans is an important preprocessing task for autonomous vehicles in on-road and especially in off-road scenarios. Clustering point measurements with the same properties into multiple homogeneous regions is a challenging task due to an uneven sampling density and lack of explicit structural information. This paper presents a novel technique to achieve a robust and fast point-cloud segmentation using the characteristic intrinsic sensor pattern. This pattern is characterized by the mounting position of each laser diode. A Structured Mesh graph is created by taking the beam calibration and the chronology of incoming data packets into account. The proposed graph-based, multi-pass point segmentation algorithm compares this pattern with a flat-world model to detect discontinuities and to set label attributes such as obstacle or free space for each vertex. Furthermore, we directly detect missing measurements and therefore generate artificial vertices considering the laser beam intrinsics. Finally, a region-growing algorithm is applied in order to obtain cohesive objects. Experimental results show that we achieve a reliable overall performance and a good trade-off between segmentation quality and runtime of 15ms in rough terrain as well as suburban areas.
Weiqun Zhang - One of the best experts on this subject based on the ideXlab platform.
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relativistic hydrodynamic flows using spatial and temporal adaptive Structured Mesh refinement
Astrophysical Journal Supplement Series, 2008Co-Authors: P Wang, Tom Abel, Weiqun ZhangAbstract:Astrophysical relativistic flow problems require high-resolution three-dimensional (3D) numerical simulations. In this paper, we describe a new parallel 3D code for simulations of special relativistic hydrodynamics (SRHD) using both spatially and temporally Structured adaptive Mesh refinement (AMR). We used the method of lines to discretize the SRHD equations spatially and a total variation diminishing (TVD) Runge-Kutta scheme for time integration. For spatial reconstruction, we have implemented piecewise linear method (PLM), piecewise parabolic method (PPM), third-order convex essentially nonoscillatory (CENO) and third- and fifth-order weighted essentially nonoscillatory (WENO) schemes. Flux is computed using either direct flux reconstruction or approximate Riemann solvers including HLL, modified Marquina flux, local Lax-Friedrichs flux formulas, and HLLC. The AMR part of the code is built on top of the cosmological Eulerian AMR code enzo. We discuss the coupling of the AMR framework with the relativistic solvers. Via various test problems, we emphasize the importance of resolution studies in relativistic flow simulations because extremely high resolution is required especially when shear flows are present in the problem. We also present the results of two 3D simulations of astrophysical jets: AGN jets and GRB jets. Resolution study of those two cases further highlights the need of high resolutions to calculate accurately relativistic flow problems.
A Paredes - One of the best experts on this subject based on the ideXlab platform.
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A penalization technique to model plasma facing components in a tokamak ă with temperature variations
Journal of Computational Physics, 2014Co-Authors: A Paredes, Philippe Ghendrih, Frédéric Schwander, Hugo Bufferand, Guido Ciraolo, Eric Serre, Patrick TamainAbstract:To properly address turbulent transport in the edge plasma region of a ă tokamak, it is mandatory to describe the particle and heat outflow on ă wall components, using an accurate representation of the wall geometry. ă This is challenging for many plasma transport codes, which use a ă Structured Mesh with one coordinate aligned with magnetic surfaces. We ă propose here a penalization technique that allows modeling of particle ă and heat transport using such Structured Mesh, while also accounting for ă geometrically complex plasma-facing components. Solid obstacles are ă considered as particle and momentum sinks whereas ionic and electronic ă temperature gradients are imposed on both sides of the obstacles along ă the magnetic field direction using delta functions (Dirac). Solutions ă exhibit plasma velocities (M = 1) and temperatures fluxes at the ă plasma-wall boundaries that match with boundary conditions usually ă implemented in fluid codes. Grid convergence and error estimates are ă found to be in agreement with theoretical results obtained for neutral ă fluid conservation equations. The capability of the penalization ă technique is illustrated by introducing the non-collisional plasma ă region expected by the kinetic theory in the immediate vicinity of the ă interface, that is impossible when considering fluid boundary ă conditions. Axisymmetric numerical simulations show the efficiency of ă the method to investigate the large-scale transport at the plasma edge ă including the separatrix and in realistic complex geometries while ă keeping a simple Structured grid. (C) 2014 Elsevier Inc. All rights ă reserved.
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A penalization technique to model plasma facing components in a tokamak with temperature variations
Journal of Computational Physics, 2014Co-Authors: A Paredes, Philippe Ghendrih, Frédéric Schwander, Hugo Bufferand, Guido Ciraolo, Eric Serre, Patrick TamainAbstract:To properly address turbulent transport in the edge plasma region of a tokamak, it is mandatory to describe the particle and heat outflow on wall components, using an accurate representation of the wall geometry. This is challenging for many plasma transport codes, which use a Structured Mesh with one coordinate aligned with magnetic surfaces. We propose here a penalization technique that allows modelingof particle and heat transport using such Structured Mesh, while also accounting for geometrically complex plasma-facing components. Solid obstacles are considered as particle and momentum sinks whereas ionic and electronic temperature gradients are imposed on both sides of the obstacles along the magnetic field direction using delta functions (Dirac). Solutions exhibit plasma velocities (M=1) and temperatures fluxes at the plasma–wall boundaries that match with boundary conditions usually implemented in fluid codes. Grid convergence and error estimates are found to be in agreement with theoretical results obtained for neutral fluid conservation equations. The capability of the penalization technique is illustrated by introducing the non-collisional plasma region expected by the kinetic theory in the immediate vicinity of the interface, that is impossible when considering fluid boundary conditions. Axisymmetric numerical simulations show the efficiency of the method to investigate the large-scale transport at the plasma edge including the separatrix and in realistic complex geometries while keeping a simple Structured grid.
