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Analysis of the thermal behavior of photoluminescent optical memory based on CaS:Eu,Sm media

Physical Review B 2005年第19期72卷 195108-195108页

作者： C. Chen K. L. Teo T. C. Chong D. M. Newman J. P. Wu Information Storage Materials Laboratory Department of Electrical and Computer Engineering National University of Singapore 4 Engineering Drive 3 Singapore 117576 and Data Storage Institute 5 Engineering Drive 1 Singapore 117608 School of Engineering Computer Science and Mathematics University of Exeter Exeter EX4 4QF United Kingdom Department of Engineering Queen Mary College University of London London United Kingdom

The temperature dependence of the photoluminescence (PL) and infrared stimulated luminescence (ISL) exhibited by CaS doped with both europium (Eu) and samarium (Sm) ions is reported for temperatures in the range between 100 and 700 K. Behavior indicative of strong electron-phonon coupling is observed in the PL emission of the Eu2+ ion and two processes with activation energies (ΔE1,ΔE2) are recognized in the quenching of the PL intensity. The smaller of these (ΔE2=0.056eV) is identified as the energy separation between Eu2+ excited states and the conduction band of CaS while ΔE1, which has a value of 0.55 eV, is attributed to some intervening quenching state. On the other hand, analysis of the integrated ISL intensity as a function of temperature prompts the conclusion that the separation (Δε) between the lowest excited energy levels of Eu2+ ions and that of Sm2+ ions is approximately 28 meV at low temperature. When it is considered for an optical memory medium, recording experiments performed at different temperatures show the writing process to be more efficient when conducted at higher temperatures rather than lower ones. Moreover, two different time constants, that are themselves linear functions of temperature, are observed to govern the readout process in which electrons trapped at the Sm ions are depleted under continuous (IR) irradiation. Finally, studies of the ISL intensity versus storage time at different temperatures show the reading output to be lowered for longer storage times due to a thermally assisted decay route facilitating the release of electrons trapped at Sm2+ ions back to Eu2+ ions.

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Solid-state lighting: Toward superior illumination

Solid-state lighting: Toward superior illumination

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作者： Shur, Michael S. Žukauskas, Arturas IIEE Japan Department of Electrical Computer and Systems Engineering and Physics Rensselaer Polytechnic Institute Troy NY 12180 United States Institute of Materials Science and Applied Research Vilnius University Vilnius 10222 Lithuania Department of Solid State Electronics United States Department of Physics Applied Physics and Astronomy United States Center for Broadband Data Transport Science and Technology Rensselaer Polytechnic Institute Troy NY United States American Physical Society United States Electrochemical Society United States World Innovation Foundation United States Eta Kappa Nu Electromagnetic Academy Materials Research Society United States American Society for Engineering Education United States SPIE United States American Association for the Advancement of Science United States IEEE Sensor Council United States Institute of Materials Science and Applied Research Lithuania Department of Semiconductor Physics Lithuania Lithuanian Physical Society Lithuania Lithuanian Materials Research Society Lithuania Lithuanian Academy of Sciences Lithuania

Solid-state lighting technology is now emerging as a cost-competitive, energy-efficient alternative to conventional electrical lighting. We review the history of lighting, discuss the benefits and challenges of the solid-state lighting technologies, and compare two approaches for generating white light from solid-state sources based on phosphor LEDs (which could be considered as solid-state replacement of fluorescent tubes) and multichip LED lamps, which offer many advantages, such as chromaticity control, better light quality, and higher efficiency. © 2005 IEEE.

关键词： Solid state devices

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Optical and Current Noise of GaN Based Light Emitting Diodes

Optical and Current Noise of GaN Based Light Emitting Diodes

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International Symposium Semiconductor Device Research (ISDRS)

作者： S. Sawyer S.L. Rumyantsev N. Pala M.S. Shur Yu. Bilenko J.P. Zhang X. Hu A. Lunev J. Deng R. Gaska Department of Electrical Computer and Systems Engineering Center for Broadband Data Transport Science and Technology CII 9017 Rensselaer Polytechnic Institute Troy NY USA Ioffe Physical-Technical Institute of the Russian Academy of Sciences Saint Petersburg Russia Sensor Electronic Technology Inc.orporated Columbia SC USA

Ultraviolet (UV) light emitting diodes (LEDs) are expected to find applications for solid-state lighting, water and air purification, bio-agent detection, and biological fluorescence experiments. For identifying miniscule amounts of hazardous biological pathogens and for the detection of fluorescence from protein molecules excited with the UV light (200-300nm) the light source must exhibit low noise and high stability over tens of minutes. The authors report on the low frequency fluctuations of the current and light intensity of SET UVTOPreg LEDs (fabricated by SET, Inc.) with wavelengths ranging from 265nm to 340nm

关键词： Optical noise Stimulated emission Gallium nitride Light emitting diodes Fluorescence Biomedical optical imaging Solid state lighting Purification Pathogens Proteins

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Journal of Information science and engineering: Editorial notice

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Journal of Information science and engineering 2005年第5期21卷 i-ii页

作者： Lee, Der-Tsai Amato, Nancy M. Chang, Shih-Fu Chen, Homer H. Chen, Tsuhan Hsu, Tsan-Sheng Hwang, Jenq-Neng Kuo, Sy-Yen Kuo, Tei-Wei Li, Chung-Sheng Tokuyama, Takeshi Wing, Jeannette Wu, Tzong-Chen Yen, John Computer Science at Texas A and M University United States Parasol Laboratory United States IEEE Transactions on Parallel and Distributed Systems Computing Research Association's Committee on the Status of Women in Computing Research CRA-W's Distributed Mentor Program United States Department of Electrical Engineering Columbia University United States Lab. United States College of Electrical Engineering and Computer Science National Taiwan University Taiwan IEEE Transactions on Circuits and Systems for Video Technology IEEE Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States ACM ACM SIGACT IEEE Computer Society IICM Austria Research and Development of the Department Multimedia Signal Processing Technical Committee IEEE Signal Processing Society United States IEEE Transactions on Circuits and systems for Video Technology College of Electrical Engineering and Computer Science National Taiwan Ocean University Keelung Taiwan Department of Electrical Engineering National Taiwan University Taiwan Department of Computer Science and Information Engineering National Taiwan University Taipei Taiwan IEEE Technical Committee on Real-Time Systems Computer Science Division IBM T.J. Watson Research Center United States IBM Research Division Graduate School of Information Sciences Tohoku University Japan ACM IPSJ Mathematical Society of Japan Japan Department of Computer Science Computer Science Department Carnegie Mellon University United States National Academies of Science's Computer Science and Telecommunications Board United States Microsoft's Trustworthy Academic Advisory Board Intel Research Pittsburgh's Advisory Board United States Dartmouth's Institute for Security Technology Studies Advisory Committee Canada Sloan Research Fellowships Program Committee United States ACM Taiwan China Information Sciences and Technology Pennsylvania State University United States Laboratory for Intelligent Agents Penn State's School of Info

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Network coding for wireless applications

Network coding for wireless applications

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Unmanned/Unattended Sensors and Sensor Networks II

作者： Lun, Desmond S. Ahmed, Ebad Brothers, L. Reggie DeBardelaben, James A. Effros, Michelle Ho, Tracey Karger, David Koetter, Ralf Lee, Anna MacMullan, Samuel J. Médard, Muriel Zhao, Fang Laboratory for Information and Decision Systems Massachusetts Institute of Technology Cambridge MA 02139 United States DARPA ATO 3701 N. Fairfax Dr. Arlington VA 22203 United States Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Rd. Laurel MD 20769 United States Data Compression Laboratory California Institute of Technology Pasadena CA 91125 United States Department of Electrical Engineering California Institute of Technology Pasadena CA 91125 United States Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology Cambridge MA 02139 United States Coordinated Science Laboratory University of Illinois at Urbana-Champaign Urbana IL 61801 United States Lorenz Research Associates Inc. 4443 Brookfield Corporate Dr. Chantilly VA 20151 United States

The advent of network coding promises to change many aspects of networking. Network coding moves away from the classical approach of networking, which treats networks as akin to physical transportation systems. We overview some of the main features of network coding that are most relevant to wireless networks. In particular, we discuss the fact that random distributed network coding is asymptotically optimal for wireless networks with and without packet erasures. These results are extremely general and allow packet loss correlation, such as may occur in fading wireless channels. The coded network lends itself, for multicast connections, to a cost optimization which not only outperforms traditional routing tree-based approaches, but also lends itself to a distributed implementation and to a dynamic implementation when changing conditions, such as mobility, arise. We illustrate the performance of such optimization methods for energy efficiency in wireless networks and propose some new directions for research in the area.

关键词： Signal encoding

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Design and implementation of algorithm with multichannel load balancing and failover for generic storage area networks 9

Design and implementation of algorithm with multichannel loa...

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9th International Conference on Communications Systems, ICCS 2004

作者： Ng, Kelvin Wang, Wilson Y.H Department of Electrical and Computer Engineering National University of Singapore Singapore Data Storage Institute Agency for Science Teclmology and Research Singapore Singapore

ISBN: (纸本)0780385497

This paper presents the design of an algorithm to provide end-toend multichannel load balancing and failover for generic SANs. A virtual channel is formed by the aggregation of multiple subchannels. This provides scalability as sub-channels can be added or removed when required. Multiple sub-channels also improve the reliability of storage network. By exchanging information between 2 hosts, the algorithm is also able to balance both the transmission and reception load. Additional information can be added to transmitted packets by lowering the MTU value of a virtual network interface. This additional information can be used to identifY the network storage protocol used so as to provide end-to-end multichannel functionality independent of the network storage protocol used. Results have shown that the implementation is able to provide higher throughput with the added benefits of end-to-end load balancing and failover to both HyperSCSI and iSCSI. © 2004 IEEE.

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An automated seamless mosaicing system of multi-charge coupled devices of panchromatic data

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Journal of the Indian Society of Remote Sensing 2004年第1期32卷 103-111页

作者： Ramakrishnan, R. Manthira Moorthi, S. Padmanabhan, N. Gupta, P. Data Products Software Division Signal and Image Processing Group Space Applications Centre (ISRO) Ahmedabad-380 015 India Department of Computer Science and Engineering Indian Institute of Technology Kanpur Kanpur 208 016 India

Panchromatic data of pixel resolution 5.8 m obtained from IRS-IC and IRS-ID satellites proved to be very useful for mapping purposes. One of the popular data product is the 70 km swath mosaic which is covered by a combination of 3 CCD line sensors, each with 4096 pixels. Each CCD-line sensor with different imaging times causes geometric problems of mosaicing three strips data together. In this paper, we propose the details of the design elements of system that caters to the need for accurate and automatic multi strip image registration without any second resampling of the data. The systematic geometric correction grid mapping is improved to facilitate accurate mosaicing by automatic image registration task that makes use of the overlap data within image strips and image registration is achieved up to sub-pixel level.

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TeraHertz detectors based on plasma oscillations in nanometric Silicon Field Effect Transistors

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physica status solidi c 2005年第4期2卷

作者： F. Teppe Y. M. Meziani N. Dyakonova J. Łusakowski F. Bœuf T. Skotnicki D. Maude S. Rumyantsev M. S. Shur W. Knap GES CNRS-Université Montpellier 2 34900 Montpellier France ST Microelectronics BP 16 38921 Crolles France Grenoble High Magnetic Field Laboratory CNRS-MPI 38 450 Grenoble France Center for Broadband Data Transport Science and Technology and Electrical Computer and System Engineering Department Rensselaer Polytechnic Institute Troy New York 121180-3590 USA Ioffe Institute of Russian Academy of Sciences 194021 St. Petersburg Russia

We report on the experiments about detection of the THz radiation by silicon FETs with nanometer gate lengths. The observed photo-responses measured as a function of the gate voltage are all in agreement with the predictions of the Dyakonov-Shur theory. The plasma wave parameters deduced from the experiments allow us to predict also the possibility of resonant detection in THz range by nanometer size silicon devices. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

关键词： 73.20.Mf 85.30.Tv

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Digital processing of position error signal in hard disk drives

Digital processing of position error signal in hard disk dri...

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IEEE Instrumentation and Measurement Technology Conference

作者： A. Al Mamun G.X. Guo K.C. Tan Yimei Liu Department of Electrical & Computer Engineering Singapore Data Storage Institute Agency for Science Technology and Research (ASTAR) Singapore

The hard disk drive (HDD) industry continues to meet the ever growing demand for storage capacity by increasing both the number of tracks on the disk surface and the number of bits recorded per track. Sensing of the position error signal (PES) plays a very important role in the precision and accuracy achieved by the track-following servomechanism. The need for better sensing of the PES made researchers explore different techniques of servo encoding - dual frequency servo burst being one of them. This paper addresses different aspects of decoding the PES from these servo bursts. An algorithm based on the discrete Fourier transform (DFT) is used. Claims are supported by both simulation and experimental data.

关键词： Signal processing Hard disks Servomechanisms Magnetic heads Frequency Magnetic separation Drives data engineering Discrete Fourier transforms Demodulation

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Non-rigid registration algorithm with spatially varying stiffness properties

Non-rigid registration algorithm with spatially varying stif...

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IEEE International Symposium on Biomedical Imaging

作者： V. Duay P.-F. D'Haese Rui Li B.M. Dawant Department of Electrical Engineering and Computer Science Vanderbilt University Nashville USA EPFL Currently with the Signal Processing Institute Lausanne Switzerland

Non-rigid registration algorithms have been proposed over the years to register medical images to each other. One class of applications for these algorithms is the automatic segmentation of structures and substructures using a predefined atlas. But these algorithms have been limited to image volumes without gross abnormalities or pathologies and have thus been of limited use for applications such as the automatic segmentation of radiation sensitive structures for radiation therapy planning. The algorithm we present in this paper is an extension of a non-rigid registration algorithm we have previously developed (the adaptive basis algorithm). This extension permits the use of the algorithm for the automatic segmentation of medical images even when structures have been displaced substantially. The algorithm automatically adjusts the stiffness of the transformation to permit larger displacements over regions that are known to be very compliant and smaller displacements over regions that are known to be less compliant. The stiffness map can be defined once and for all in an atlas. The algorithm has been tested and evaluated on head image volumes with large ventricular enlargements and head image volumes with large space-occupying lesions.

关键词： Signal processing algorithms Image segmentation Lesions Registers Biomedical imaging Biomedical applications of radiation Head Application software Pathology Path planning

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