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3-d design and analysis of functional NEMS-gate MOSFETs and SETs

IEEE TRANSACTIONS ON NANOTECHNOLOGY 2007年第2期6卷 218-224页

作者： Pruvost, Benjamin Mizuta, Hiroshi Oda, Shunri Tokyo Inst Technol Quantum Nanoelect Res Ctr Tokyo 1528552 Japan Tokyo Inst Technol Dept Phys Elect Tokyo 15285552 Japan Japan Sci & Technol SORST Tokyo 15285552 Japan

Nanoelectromechanical system (NEMS)-gate metal-oxide-semiconductor field effect transistor (MOSFET) and single-electron transistor (SET) structures are investigated by combining 3-d design and SPICE simulation. First, the metal gate is simulated by using a 3-d simulator, which enables to design realistic 3-d device structures, and its movement is studied for different design parameters. It is demonstrated that a low stiffness design of the structure is essential for a low-voltage actuation. Results are compared with theoretical numerical simulation and a tunable capacitor model is then embedded in a SPICE simulator and coupled either with a transistor model for MOS-NEMS or with a newly developed SET analytical model for SET-NEMS. It is shown that the use of NEMS membrane can add new functionalities to conventional MOSFET and SET, such as very abrupt switching of the current, which can break theoretical limits of MOSFET, or modulation of Coulomb oscillations governing SET characteristics.

关键词： analytical modeling metal-oxide-semiconductor field effect transistor (MOSFET) movable gate nanoelectromechanical system (NEMS) single-electron transistor (SET) 3-d modeling

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d-side:: A facility and workforce planning group multi-criteria decision support system for Johnson Space Center

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COMPUTERS & OPERATIONS RESEARCH 2007年第6期34卷 1646-1673页

作者： Tavana, Madjid Smither, James W. Anderson, Ralph V. La Salle Univ Dept Management Philadelphia PA 19141 USA NASA Lyndon B Johnson Space Ctr Syst Management Off Houston TX 77058 USA

"To understand and protect our home planet, to explore the universe and search for life, and to inspire the next generation of explorers" is NASA's mission. The Systems Management Office at Johnson Space Center (JSC) is searching for methods to effectively manage the Center's resources to meet NASA's mission. d-Side is a group multi-criteria decision support system (GMdSS) developed to support facility decisions at JSC. d-Side uses a series of sequential and structured processes to plot facilities in a three-dimensional (3-d) graph on the basis of each facility's alignment with NASA's mission and goals, the extent to which other facilities are dependent on the facility, and the dollar value of capital investments that have been postponed at the facility relative to the facility's replacement value. A similarity factor rank orders facilities based on their Euclidean distance from Ideal and Nadir points. These similarity factors are then used to allocate capital improvement resources across facilities. We also present a parallel model that can be used to support decisions concerning allocation of human resources investments across workforce units. Finally, we present results from a pilot study where 12 experienced facility managers from NASA used d-Side and the organization's current approach to rank order and allocate funds for capital improvement across 20 facilities. Users evaluated d-Side favorably in terms of ease of use, the quality of the decision-making process, decision quality, and overall value-added. Their evaluations of d-Side were significantly more favorable than their evaluations of the current approach. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： NASA multi-criteria decision making decision support system AHP Euclidean distance 3-d modeling facility planning workforce planning

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Perspective 3-d Euclidean Reconstruction With Varying Camera Parameters

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IEEE TRANSACTIONS ON CIRCUITS ANd SYSTEMS FOR VIdEO TECHNOLOGY 2009年第12期19卷 1793-1803页

作者： Wang, Guanghui Wu, Q. M. Jonathan Univ Windsor Dept Elect & Comp Engn Windsor ON N9B 3P4 Canada

The paper addresses the problem of 3-d Euclidean structure and motion recovery from video sequences based on perspective factorization. It is well known that projective depth recovery and camera calibration are two essential and difficult steps in metric reconstruction. We focus on the difficulties and propose two new algorithms to improve the performance of perspective factorization. First, we propose to initialize the projective depths via a projective structure reconstructed from two views with large camera movement, and optimize the depths iteratively by minimizing reprojection residues. The algorithm is more accurate than previous methods and converges quickly. Second, we propose a self-calibration method based on the Kruppa constraint to deal with more general camera model. The Euclidean structure can be recovered from factorization of the normalized tracking matrix. Extensive experiments on synthetic data and real sequences are performed to validate the proposed method and good improvements are observed.

关键词： Camera self-calibration computer vision 3-d modeling Kruppa constraint matrix factorization structure from motion

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COMPUTERIZEd FIELd-dATA CAPTURE ANd GIS ANALYSIS FOR GENERATION OF CROSS-SECTIONS IN 3-d PERSPECTIVE VIEWS

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COMPUTERS & GEOSCIENCES 1995年第5期21卷 687-701页

作者： SCHETSELAAR, EM International Institute for Aerospace Survey and Earth Sciences P.O. Box 6 7500 AA Enschede The Netherlands

A method for field-data capture and Geographic Information System analysis for representation of cross sections in 3-d is discussed, in which digital storage and management of field-collected structural elements facilitates GIS analytical processing and visualization. Raster-to-point, vector-to-point conversions and spreadsheet calculations were combined in a batch-routine to generate displays of cross sections with projected structural elements stacked in perspective views. The method demonstrates how 2-d GIS software can be exploited for 3-d visualization of geologic structures.

关键词： FIELd-dATA CAPTURE GIS ANALYSIS CROSS SECTIONS 3-d modeling

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geomIO: An Open-Source MATLAB Toolbox to Create the Initial Configuration of 2-d/3-d Thermo-Mechanical Simulations From 2-d Vector drawings

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GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 2019年第3期20卷 1665-1675页

作者： Bauville, A. Baumann, T. S. Japan Agcy Marine Earth Sci & Technol Dept Math & Adv Technol Yokohama Kanagawa Japan Johannes Gutenberg Univ Mainz Inst Geosci Mainz Germany

Creating the initial geometry and temperature configuration of 3-d numerical simulations is a challenging task. Professional tools are expensive. They often have a steep learning curve and do mostly not interface with the numerical simulation software used by the geodynamics and tectonics academic community. There, we developed geometry Input/Output (geomIO), a MATLAB toolbox to create the initial configuration of geological models regarding model geometry and temperature structure. geomIO allows users to create a geo-referenced 3-d volume by drawing multiple 2-d cross sections in a standard vector graphics editor. The volume is then used to assign material properties and set up initial temperature distribution on a set of vertices. In 2-d mode, polygons can also be used to create a triangular mesh. In addition to the standard functionality, the gravity anomaly of any geometry created with geomIO can be calculated. In this paper, we give an overview of the basic functionalities of geomIO. We illustrate the strength of our software with advanced tectonic and geodynamic applications that could not have been performed with currently available free software. Applications include the Himalayan orogen, the Japanese subduction zones, present-day salt diapirs, and small-scale tectonic structures. We describe algorithms and file formats in the supporting information. The toolbox is user-friendly and flexible. Users can use custom pipelines or preset data processing pipelines, so most applications require only a few lines of code. geomIO is distributed under the GNU General Public License and includes an online wiki with tutorials and additional examples. Plain Language Summary Numerical methods are often used to simulate complex physical processes like the deformation of materials. However, creating the initial geometry and temperature configuration of three-dimensional (3-d) numerical simulations is a challenging task. Professional tools are expensive, have a high learning

关键词： 3-d modeling numerical simulation MATLAB toolbox 3-d temperature distribution

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3-d prediction of alloy solidification in the presence of turbulent fow in a vertical direct chill caster with a porous filter near the top

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APPLIEd MATHEMATICAL MOdELLING 2016年第21-22期40卷 9029-9051页

作者： Begum, Latifa Hasan, Mainul McGill Univ Dept Min & Mat Engn MH Wong Bldg3610 Univ St Montreal PQ H3A 0C5 Canada

An industrial size vertical direct Chill (dC) caster fitted with a porous filter above the mold is simulated by developing control volume finite difference based computational fluid dynamics code. Specifically, the 3-d laminar/turbulent melt flow in the sump and mushy zone solidification characteristics in the dC caster are modeled for aluminium alloy AA-1050. To account for the turbulence in the sump a popular version of the low Reynolds number kappa-omega model is employed. A single domain enthalpy-porosity approach is used to account for the solidification heat transfer of the above short solidification range alloy. The melt flows through the stainless steel porous filter placed near the top of the caster is modeled using the Brinkman-Forchheimer extended darcy equation and by invoking the local thermal equilibrium condition between the melt and the porous structure. The verified code is used to study the effects of casting speed and heat transfer coefficient in the metal-mold contact region on various aspects of this casting problem. Sensitivity analysis is also carried out by varying the latent heat of solidification of the said alloy. The predicted results are presented and discussed for the solid-shell thickness, the sump depth, the mushy layer thickness as well as for the temperature and velocity fields. (C) 2016 Elsevier Inc. All rights reserved.

关键词： 3-d modeling Vertical dC caster Turbulent melt flow Rolling ingot Porous filter

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2-d versus 3-d magnetotelluric data interpretation

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SURVEYS IN GEOPHYSICS 2005年第5期26卷 511-543页

作者： Ledo, J Univ Barcelona Dept Geodinam & Geofis E-08028 Barcelona Spain

In recent years, the number of publications dealing with the mathematical and physical 3-d aspects of the magnetotelluric method has increased drastically. However, field experiments on a grid are often impractical and surveys are frequently restricted to single or widely separated profiles. So, in many cases we find ourselves with the following question: is the applicability of the 2-d hypothesis valid to extract geoelectric and geological information from real 3-d environments? The aim of this paper is to explore a few instructive but general situations to understand the basics of a 2-d interpretation of 3-d magnetotelluric data and to determine which data subset (TE-mode or TM-mode) is best for obtaining the electrical conductivity distribution of the subsurface using 2-d techniques. A review of the mathematical and physical fundamentals of the electromagnetic fields generated by a simple 3-d structure allows us to prioritise the choice of modes in a 2-d interpretation of responses influenced by 3-d structures. This analysis is corroborated by numerical results from synthetic models and by real data acquired by other authors. One important result of this analysis is that the mode most unaffected by 3-d effects depends on the position of the 3-d structure with respect to the regional 2-d strike direction. When the 3-d body is normal to the regional strike, the TE-mode is affected mainly by galvanic effects, while the TM-mode is affected by galvanic and inductive effects. In this case, a 2-d interpretation of the TM-mode is prone to error. When the 3-d body is parallel to the regional 2-d strike the TE-mode is affected by galvanic and inductive effects and the TM-mode is affected mainly by galvanic effects, making it more suitable for 2-d interpretation. In general, a wise 2-d interpretation of 3-d magnetotelluric data can be a guide to a reasonable geological interpretation.

关键词： 2-d modeling 3-d modeling magnetotelluric theory

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3-d Analytical Model of Helical Winding PM Machines Including Rotor Eddy Currents

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IEEE TRANSACTIONS ON MAGNETICS 2016年第5期52卷 1-8页

作者： Jumayev, S. Paulides, J. J. H. Boynov, K. O. Pyrhonen, J. Lomonova, E. A. Eindhoven Univ Technol Dept Elect Engn NL-5612 AZ Eindhoven Netherlands Lappeenranta Univ Technol Dept Elect Engn Lappeenranta 53850 Finland

Helical windings (or zigzag windings) are used in a number of applications, however, in electrical machines, mainly employed in low-power, high-speed permanent magnet (PM) brushless dc machines due to the cost effectiveness of the winding type while maintaining reasonable performance. Typically, helical windings are used for low-voltage applications due to their spiral form, which makes them most suitable for a small number of turns. In high-speed electrical machines, such a low number of turns are applicable. It is apparent that high-speed PM machines suffer from rotor eddy-current losses, which in some cases may lead to PM demagnetization due to overheating. The performance of the machine is compromised by these losses;hence, they have to be considered during the design procedure. There are many papers analyzing the magnetic field of these machines employing helical windings;however, none of them present a simple and precise electromagnetic model of a machine with the helical winding. This paper presents an analytical approach to model the resulting 3-d magnetic field of the helical winding, considering eddy currents in the conducting media of the rotor. The model is verified with the 3-d finite-element method by means of comparing magnetic field and rotor eddy-current losses.

关键词： 3-d modeling Faulhaber winding Fourier modeling helical winding rotor eddy currents

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Fast and Accurate Investigation of 2-d Multilayered Photonic Crystals by a 3-d Model Based on the Green's Function

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IEEE JOURNAL OF QUANTUM ELECTRONICS 2010年第11期46卷 1549-1560页

作者： Ciminelli, Caterina Marani, Roberto Armenise, Mario Nicola Politecn Bari Elect & Elect Dept Optoelect Lab I-70125 Bari Italy

In this paper, a 3-d model based on the Green's function for analyzing wave propagation in 2-d guided-wave photonic crystals (PhCs) is proposed. The model allows analysis all the physical effects occurring when a source field propagates in a multilayered structure with a periodic arrangement of scatterers, by taking into account both physical and geometrical parameters. Numerical results for PhC waveguides are compared with those obtained using the well-known finite-difference time-domain algorithm and the 3-d multiple-scattering technique already proposed in the literature, showing a very good agreement and some remarkable advantages, in terms of faster determination of electromagnetic field distributions and band diagrams and capability to analyze both in-plane and out-of-plane scattering losses.

关键词： 3-d modeling Green's function multilayered photonic crystals photonic bandgap waveguide photonic crystals

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Challenging Vertical Turbulence Mixing Schemes in a Tidally Energetic Environment: 1.3-d Shelf-Sea Model Assessment

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JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 2019年第8期124卷 6360-6387页

作者： Luneva, Maria, V Wakelin, Sarah Holt, Jason T. Inall, Mark E. Kozlov, Igor E. Palmer, Matthew R. Toberman, Matthew Zubkova, Evgenia, V Polton, Jeff A. Natl Oceanog Ctr Liverpool Merseyside England Scottish Assoc Marine Sci SAGES Oban Argyll Scotland Russian State Hydrorneteorol Univ Satellite Oceanog Lab St Petersburg Russia RAS Marine Hydrophys Inst Sevastopol Crimea Ukraine

Mixing in the ocean and shelf seas is critical for the vertical distribution of dynamically active properties, such as density and biogeochemical tracers. Eight different decadal simulations are used to assess the skill of vertical turbulent mixing schemes (TMS) in a 3-d regional model of tidally active shelf seas. The TMS differ in the type of stability functions used and in the Ozmidov/deardorff/Galperin limiter of the turbulence length scales. We review the dependence of the critical Richardson and Prandtl numbers to define the "diffusiveness" of the TMS. The skill in representing bias and variability of stratification profiles is assessed with five different metrics: surface and bottom temperatures and pycnocline depth, thickness, and strength. The assessment is made against hydrography from three data sets (28,000 profiles in total). Bottom and surface temperatures are found to be as sensitive to TMS choice as to horizontal resolution or heat flux formulation, as reported in other studies. All TMS underrepresent the pycnocline depth and benthic temperatures. This suggests physical processes are missing from the model, and these are discussed. different TMSs show the best results for different metrics, and there is no outright winner. Simulations coupled with an ecosystem model show the choice of TMS strongly affects the ecosystem behavior: shifting the timing of peak chlorophyll by 1 month, showing regional chlorophyll differences of order 100%, and redistributing the production of chorophyll between the pycnocline and mixed layer.

关键词： turbulence closure assessment 3-d modeling pycnocline mixing

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