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A Novel 1.5 $^primeprime$ Quadruple Antenna for Tri-Band GPS Applications

IEEE Antennas and Wireless Propagation Letters 2006年 5卷 224-227页

作者： Y. Zhou S. Koulouridis G. Kiziltas J. L. Volakis Electroscience Laboratory Electrical and Computer Engineering Department Ohio State Uinversity Columbus OH USA Mechatronics Program of the Faculty of Engineering and Natural Sciences Sabanci University Istanbul Turkey

A new global positioning system (GPS) antenna is proposed to cover the three GPS bands (L1, L2, and L5, namely 1575, 1227, and 1176 MHz) with the L5 band to be added after 2006. The developed antenna size is only $1.5^primeprimetimes 1.5^primeprime$ in aperture corresponding to $lambda/7timeslambda/7$ $(lambda=hboxfree hboxspace hboxwavelength)$ and $lambda/13 hboxthick$. Quadrature feeding is employed to ensure right-hand circular polarized (RHCP) radiation. The final miniature antenna exhibits a gain greater than 2 dBi, and to our knowledge this is the smallest such size for circular polarized (CP) operation covering all three bands. Detailed parametric simulations leading to the best design along with measurements for the constructed antenna are presented.

关键词： Global Positioning System Conductors Dielectric substrates Bandwidth Resonance Aperture antennas Polarization Shape Permittivity Antenna measurements

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Bi-Sr-Ca-Cu-O superconducting thin films: Theory and experiment

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Journal of Physics: Conference Series 2006年第1期43卷 277-280页

作者： Yavuz, M. Boybay, M.S. Elbuken, C. Andrews, M.J. Hu, C.R. Ross, J.H. Department of Mechanical Engineering Mechatronics Engineering Program University of Waterloo Waterloo Ont. N2L 3G1 Canada Los Alamos National Lab. Mail Stop B 296 Los Alamos NM 87545 PO Box 1663 United States Department of Physics Texas A and M University College Station TX 77843 United States

The interest of this paper centers on fabrication and characterization and modeling of vortices in high temperature superconducting thin films. As a first step, the magnetic vertices of the superconducting matrix were modeled. As a second, Bi-Sr-Ca-Cu-O thin films were grown using Pulsed Laser Ablation (PLD) on single crystal MgO substrates as magnetic templates for the potential use for Nano and Microelectronic circuits, and were characterized by x-ray diffraction, electron, and atomic force microscopy. The third step (future work) will be observation and pinning of these vortices using Bitter decoration. © 2006 IOP Publishing Ltd.

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Bilateral control with a reflex mechanism on the slave side

Bilateral control with a reflex mechanism on the slave side

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IECON 2005: 31st Annual Conference of IEEE Industrial Electronics Society

作者： Onal, Cagdas Denizel Sabanovic, Asif Sabanci University Faculty of Engineering and Natural Sciences Mechatronics Program Istanbul 34956 Turkey

ISBN: (纸本)0780392523

In this work, we are presenting a sliding mode controller approach for bilateral control. The controller consists of sliding mode force and hybrid (force/position) controllers for master and slave sides, respectively. Main issues such as transparency and time delay have been adressed in the derivation and the implementation of the controller. The approach takes the overall system (unified master and slave sides) as one system and therefore uses the transparency aims of the other approaches as the means for the derivation of the controller. It also makes use of a "reflex mechanism" to protect the slave side and its environment in case of large time delays, which disables the operator to react in time. The effectiveness of the proposed control scheme is evaluated experimentally and a maximum position error of one step increment of the encoder and a maximum torque error of 3 × 10-6Nm are achieved. ©2005 IEEE.

关键词： Control systems

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Optimal distribution of carbon nanotubes in gas sensor design

Optimal distribution of carbon nanotubes in gas sensor desig...

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2005 5th IEEE Conference on Nanotechnology

作者： Eriten, Melih Yesilyurt, Serhat Mechatronics Program Faculty of Engineering and Natural Sciences Sabanci University Istanbul 34956 Turkey

ISBN: (纸本)0780391993

Breakdown voltage is a unique well-known indicator for gases. Previous work indicate that miniaturized gas ionization sensors, which are made up of two electrodes one of which accommodates vertically aligned carbon nanotubes (CNTs), reduce breakdown voltage thanks to electric field concentration at sharp tips. Modeling of the ionization of the breakdown voltage and optimization of CNTs distribution are reported here. Modeling of CNTs for computational simulations creates a common high aspect-ratio problem due to CNT's microscale length and nanoscale diameter. This problem is solved by comparison of several models and validation of the most reliable one. Three dimensional modeling with periodic boundary conditions is proven quite suitable for actual span of CNTs on a SiO2 substrate. Using the model an optimal distribution of CNTs is obtained. ©2005 IEEE.

关键词： Carbon nanotubes

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Real time, dynamic target tracking using image motion

Real time, dynamic target tracking using image motion

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2005 IEEE International Conference on mechatronics, ICM '05

作者： Saeed, Israr Ahmed Khan Afzulpurkar, Nitin V. Industrial System Engineering Asian Institute of Technology Bangkok Thailand Asian Institute of Technology Bangkok Thailand Mechatronics and Microeletronis Program Asian Institute of Technology Thailand

ISBN: (纸本)0780389980

This paper describes the application of real time vision system for dynamic tracking of moving objects, using image motion. The study encompasses experimental development of an Intelligent system that works in ordinary light and is capable of tracking moving objects with unpredictable motion. In this research the task of mobile target tracking using a pan-and-tilt camera is considered with motion-based dynamic target tracking to deal with complex targets (shape and motion pattern unknown). We propose a method based on retrieving the target position in the image from its estimated motion. Our proposed method is based on obtaining a desired 2-D motion field in the image sequence. In this study we link variations of visual features linearly to the camera velocity. Stereovision technique is used to calculate the maximum angular displacement to retrieve the object position in image and to get the direction of motion of the object. The results are obtained in a real time test environment and are discussed. We developed the program in C++ language for linking all the algorithms in one chain. The complete target tracking algorithm works in a real time mode and can be utilized for a number of applications. © 2005 IEEE.

关键词： Tracking (position)

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Optimal distribution of carbon nanotubes in gas sensor design

Optimal distribution of carbon nanotubes in gas sensor desig...

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IEEE Conference on Nanotechnology

作者： M. Eriten S. Yesilyurt Mechatronics Program Faculty of Engineering and Natural Sciences Sabanci University Istanbul Turkey

Breakdown voltage is a unique well-known indicator for gases. Previous work indicate that miniaturized gas ionization sensors, which are made up of two electrodes one of which accommodates vertically aligned carbon nanotubes (CNTs), reduce breakdown voltage thanks to electric field concentration at sharp tips. Modeling of the ionization of the breakdown voltage and optimization of CNTs distribution are reported here. Modeling of CNTs for computational simulations creates a common high aspect-ratio problem due to CNT's microscale length and nanoscale diameter. This problem is solved by comparison of several models and validation of the most reliable one. Three dimensional modeling with periodic boundary conditions is proven quite suitable for actual span of CNTs on a SiO/sub 2/ substrate. Using the model an optimal distribution of CNTs is obtained.

关键词： Carbon nanotubes Gas detectors Ionization Anodes Electric breakdown Temperature sensors Gases Electrodes Magnetic sensors Magnetic resonance imaging

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A mini-baja active suspension modelling using ADAMS/CAR®

A mini-baja active suspension modelling using ADAMS/CAR&reg

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16th IASTED International Conference on Modelling and Simulation

作者： Drivet, Aline Ramírez-Mendoza, Ricardo A. Morales-Menéndez, Rubén Peña, Fernando ITESM Monterrey Campus Mechatronics Engineering Program Ave. Garza Sada Sur # 2501 Monterrey Nuevo León Mexico Center for Innovation in Design and Technology Ave. Garza Sada Sur # 2501 Monterrey Nuevo León Mexico

This paper presents a study of the modelling of a Minibaja vehicle. The full-scale nonlinear model of the vehicle was performed with a commercial software. Additionally, some active suspension control laws have been t... 详细信息

关键词： Computer simulation

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Neural nets modelling for automotive welding process

Neural nets modelling for automotive welding process

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16th IASTED International Conference on Modelling and Simulation

作者： Mendoza, Ricardo A. Ramírez Morales-Menéndez, Rubén Cantú-Ortiz, Francisco J. Mechatronics Engineering Program ITESM Monterrey Campus Av. E. Garza Sada # 2501 64849 Monterrey NL Mexico Center for Innovation in Design and Technology ITESM Monterrey Campus Av. E. Garza Sada# 2501 64849 Monterrey NL Mexico Graduate Studies Office ITESM Monterrey Campus Av. E. Garza Sada # 2501 64849 Monterrey NL Mexico

In this paper the authors study the applicability of Artificial Neural Networks for the modelling of a widely used particular welding process in automotive industry: pulsed gas metal welding process (GMAW-P). Applying this artificial intelligence technology requires the introduction of input and output data to the network. To achieve this, an experiment was designed and performed. The main functions of the proposed model are: to simulate the process for purposes of training operators;to improve welding process performance by identifying regions that are insensible to variations on input parameters;and finally to increase the flexibility of a robotic welding cell. The concrete benefits obtained from the GMAW-P process model development are: optimization of critical variables of the welding process, support for development of virtual process and prototypes, definition of a robust welding procedure, quick response to product change and support in welding training.

关键词： Welding

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Influence of power on the structure and mechanical properties of TiN coatings deposited by rf magnetron

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physica status solidi c 2005年第10期2卷

作者： J. E. Alfonso Fernando Pacheco Álvaro Castro P. J. Torres Physics of Condensed Matter Group Physics Department Universidad Nacional de Colombia Bogotá Centro Internacional de Física (CIF) Bogotá Colombia M. Sc. Program of Materials and Processes Mechanics and Mechatronics Engineering Department Universidad Nacional de Colombia Bogotá

Nitrides of transition metals, such as Ti, attract significant interest since they find a wide field of applications ranging from cutting tools to electronic device applications. Titanium nitride is broadly used as a hard protective coating for tribologic applications and for high temperature structural materials. In this work we present the results obtained in the growth of the titanium nitride (TiN) thin films in reactive phase by rf magnetron technique on AISI 420 steels. The depositions of TiN were carried out at a pressure of 7 × 10 –3 mbar in an atmosphere of N 2 and Ar; we took as study parameter the incident power on the target of Ti (99.9). The films were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The study of XRD showed that films grown with power at 200 W are polycrystalline, while films grown between 350 W and 750 W built the (111) plane of the TiN phase in predominant form and at 800 W there is a change of the growth direction to the (200) plane. The analysis of the Energy Dispersive X-ray Spectroscopy (EDXS) indicated that the films grew stoichiometrically. On the other hand, the hardness tests determined that the films have micro-hardness with values that increased with the power applied to the target; the highest value was 2300 Knoops for the films grown at 500 W. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

关键词： 68.55.Jk 68.55.Nq 68.60.Bs 81.15.Cd

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Influence of the substrate bias voltage on the crystallographic structure and mechanical properties of Ti6Al4V coatings deposited by rf magnetron

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physica status solidi c 2005年第10期2卷

作者： J. E. Alfonso Fernando Pacheco Alvaro Castro P. J. Torres Physics of Condensed Matter Group Physics Department Universidad Nacional de Colombia A.A. 14490 Bogotá DC Colombia Centro Internacional de Física (CIF) A.A. 14490 Bogotá DC Colombia M. Sc. Program of Materials and Processes Mechanics and Mechatronics Engineering Department Universidad Nacional de Colombia A.A. 14490 Bogotá DC Colombia

Physical and mechanical properties of pure titanium are improved when the material is mixed with aluminum and vanadium at specific concentrations. Specifically, the alloy composed by 90% of titanium, 6% of aluminum and 4% of vanadium (Ti-6Al-4V) is highly resistant to fatigue and corrosion titanium and their alloys can be deposited by two techniques: Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD). However, some problems are generated when carbonated steel substrates are used under the CVD technique, mainly because those substrates lost its carbon as a result of the high substrate temperature used during the deposition process. Alternatively, PVD (magnetron sputtering, ion plating) is a low temperature substrate process and also has the advantage that substrate bias can promote structure refinement through resputtering effects. Substrate bias influence on the crystalline structure of Ti6Al4V thin films prepared by rf magnetron sputtering are presented in this work. Samples were grown onto common glass and AISI 420 steel substrates using a Ti6Al4V (99.9 %) target. Substrate bias was varied from –100 V to –200 V. Samples were characterized by X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDXS), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). Thin films stoichiometry were studied by EDX in agreement with the Ti-6Al-4V target. Finally, the studies of the mechanical behavior of the films on steel showed that the hardness increased 1100 Knoop when the bias voltage is raised to –160 V. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

关键词： 68.55.Jk 68.55.Nq 68.60.Bs 81.15.Cd

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