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IEEE NW Russia Young Researchers in Electrical and Electronic engineering conference (EIConRusNW)

作者： A. S. Evseenkov S. A. Tarasov I. A. Lamkin A. v. Solomonov S. Yu. Kurin Saint-Petersburg Electrotechnical University “LETI” St. Petersburg Russia Nitride Crystals Ltd St. Petersburg Russia

The Uv LED heterostructures have been obtained by HvPE approach and investigated by XRD, AFM and PL methods. The experiment shows that the peak wavelength of Uv LEDs is in the range of 360-365 nm with FWHM of 10-13 nm. At operating current of 20 mA the active region temperature Tj is 43 °C, the output optical power and efficiency - 1.14 mW and 1.46 %, respectively. It is presented a model based on corpuscular Monte Carlo method in order to calculate the light extraction index. The simulation results allow us to propose the ways to increase the efficiency of Uv LEDs by 3-4 times: surface interfaces texturing, optimization of the design of heterostructures, and the use of lenses.

关键词： Light emitting diodes Gallium nitride Indexes Epitaxial growth RNA Power lasers Photonics

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Afocal viewport optics for underwater imaging 15

Afocal viewport optics for underwater imaging

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conference on current developments in Lens design and optical engineering Xv

作者： Slater, Dan 1352 Dorothea Rd La Habra Hts CA 90631 USA

ISBN: (纸本)9781628412192

A conventional camera can be adapted for underwater use by enclosing it in a sealed waterproof pressure housing with a viewport. The viewport, as an optical interface between water and air needs to consider both the camera and water optical characteristics while also providing a high pressure water seal. Limited hydrospace visibility drives a need for wide angle viewports. Practical optical interfaces between seawater and air vary from simple flat plate windows to complex water contact lenses. This paper first provides a brief overview of the physical and optical properties of the ocean environment along with suitable optical materials. This is followed by a discussion of the characteristics of various afocal underwater viewport types including flat windows, domes and the Ivanoff corrector lens, a derivative of a Galilean wide angle camera adapter. Several new and interesting optical designs derived from the Ivanoff corrector lens are presented including a pair of very compact afocal viewport lenses that are compatible with both in water and in air environments and an afocal underwater hyper-hemispherical fisheye lens.

关键词： Afocal lens design underwater photography water contact lens Ivanoff corrector lens dome port hyperhemispherical fisheye lens

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Numerical simulation for horizontal subsurface flow constructed wetlands: A short review including geothermal effects and solution bounding in biodegradation procedures

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AIP conference Proceedings 2016年第1期1773卷

作者： K. Liolios v. Tsihrintzis P. Angelidis K. Georgiev I. Georgiev Institute of Information and Communication Technologies Bulgarian Academy of Sciences Sofia Bulgaria Department of Infrastructure and Surveying Engineering School of Rural and Surveying Engineering National Technical University of Athens Athens Greece Laboratory of Hydraulics and Hydraulic Works Department of Civil Engineering Democritus University of Thrace Xanthi Greece Institute of Mathematics and Informatics Bulgarian Academy of Sciences Sofia Bulgaria

current developments on modeling of groundwater flow and contaminant transport and removal in the porous media of Horizontal Subsurface Flow Constructed Wetlands (HSF CWs) are first reviewed in a short way. The two usual environmental engineering approaches, the black-box and the process-based one, are briefly presented. Next, recent research results obtained by using these two approaches are briefly discussed as application examples, where emphasis is given to the evaluation of the optimal design and operation parameters concerning HSF CWs. For the black-box approach, the use of Artificial Neural Networks is discussed for the formulation of models, which predict the removal performance of HSF CWs. A novel mathematical prove is presented, which concerns the dependence of the first-order removal coefficient on the Temperature and the Hydraulic Residence Time. For the process-based approach, an application example is first discussed which concerns procedures to evaluate the optimal range of values for the removal coefficient, dependent on either the Temperature or the Hydraulic Residence Time. This evaluation is based on simulating available experimental results of pilot-scale units operated in Democritus University of Thrace, Xanthi, Greece. Further, in a second example, a novel enlargement of the system of Partial Differential Equations is presented, in order to include geothermal effects. Finally, in a third example, the case of parameters uncertainty concerning biodegradation procedures is considered and the use of upper and a novel approach is presented, which concerns the upper and the lower solution bound for the practical draft design of HSF CWs.

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design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye 15

Design and analysis of an adaptive lens that mimics the perf...

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conference on current developments in Lens design and optical engineering Xv

作者： Santiago-Alvarado, Agustin Cruz-Felix, Angel S. Iturbide-Jimenez, F. Martinez-Lopez, M. Ramirez-Como, M. Armengol-Cruz, v. vasquez-Baez, I. Mixteca Technol Univ Huajuapan De Leon 69000 Oax Mexico

ISBN: (纸本)9781628412192

Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.;this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks (R). We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO (R).

关键词： Solid elastic lens tunable lens crystalline lens PDMS

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Multi-aperture microoptical system for close-up imaging 15

Multi-aperture microoptical system for close-up imaging

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conference on current developments in Lens design and optical engineering Xv

作者： Berlich, Rene Brueckner, Andreas Leitel, Robert Oberdoerster, Alexander Wippermann, Frank Braeuer, Andreas Fraunhofer Inst Appl Opt & Precis Engn D-07745 Jena Germany

ISBN: (纸本)9781628412192

Modern applications in biomedical imaging, machine vision and security engineering require close-up optical systems with high resolution. Combined with the need for miniaturization and fast image acquisition of extended object fields, the design and fabrication of respective devices is extremely challenging. Standard commercial imaging solutions rely on bulky setups or depend on scanning techniques in order to meet the stringent requirements. Recently, our group has proposed a novel, multi-aperture approach based on parallel image transfer in order to overcome these constraints. It exploits state of the art microoptical manufacturing techniques on wafer level in order to create a compact, cost-effective system with a large field of view. However, initial prototypes have so far been subject to various limitations regarding their manufacturing, reliability and applicability. In this work, we demonstrate the optical design and fabrication of an advanced system, which overcomes these restrictions. In particular, a revised optical design facilitates a more efficient and economical fabrication process and inherently improves system reliability. An additional customized front side illumination module provides homogeneous white light illumination over the entire field of view while maintaining a high degree of compactness. Moreover, the complete imaging assembly is mounted on a positioning system. In combination with an extended working range, this allows for adjustment of the system's focus location. The final optical design is capable of capturing an object field of 36x24 mm(2) with a resolution of 150 cycles/mm. Finally, we present experimental results of the respective prototype that demonstrate its enhanced capabilities.

关键词： Multi-aperture imaging microoptics multi-channel optical design image sensors

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Synthesis, characterization and properties of yellow-light-emitting polyethers containing bis(styryl)anthracene units

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AIP conference Proceedings 2015年第1期1646卷 129-137页

作者： M. Gioti C. Pitsalidis A. K. Andreopoulou E. Mparmpoutsis L. Tzounis J. K. Kallitsis S. Logothetidis Laboratory for Thin Films-Nanosystems and Nanometrology (LTFN) Physics Department Aristotle University of Thessaloniki GR-54124 Thessaloniki Greece Department of Chemistry University of Patras University Campus Rio-Patras GR26504 Greece and Foundation for Research and Technology Hellas Institute of Chemical Engineering Sciences (FORTH/ICE-HT) Platani Str. Patras GR26504 Greece Department of Chemistry University of Patras University Campus Rio-Patras GR26504 Greece

Aromatic aliphatic polyethers containing bis(styryl)anthracene units in the main chain separated by flexible spacer of 11 (AND52) or 12 (AND53) methylene units, were synthesized and characterized aiming to be applied as emitting materials in polymer light emitting diode (PLED) devices. The polymers are soluble in common organic solvents and have average molecular weight of about 15kDa. Differentiations owing to an odd-even number of methylene units (χ=11 vs χ=12) are observed in their optical properties in solid state. Thin films as well as PLED devices were fabricated via conventional spin-coating process. Initially, various parameters have been investigated concerning the solubility of the polymers, the effect of film thickness on the electrical properties, and their thermal stability. The optical properties of the two polymers were investigated by NIR-vis-far Uv spectroscopic ellipsometry (SE). The accurate determination of the thickness and the optical constants (refractive index and dielectric function as a function of wavelength) were derived. These provide substantial insights into the final design of the optimum final multi-layer structure of the PLEDs, if we take into account that the external quantum efficiency (EQE) of electroluminescence (EL) strongly depends on the optical interference of the beams of emitted light that have been multiply reflected from the layer interfaces. The morphological characterization of the AND52 and AND53 polymeric thin films was carried out using atomic force microscopy (AFM), while current density-voltage (J-v) characteristics of the devices were studied by electrical measurements. The single PLED devices were switched on at relatively low operation voltages, showing the potential as backplanes for active matrix PLED applications. In this perspective, it can be assumed that further studies of the presented materials will enable the development of flexible PLEDs with the possibility to scale up their dimensions for bigger act

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Impact of electromagnetic fields on human vestibular system and standing balance: pilot results and future developments

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IOP conference Series: Materials Science and engineering 2016年第1期120卷

作者： A Allen S villard M Corbacio D Goulet M Plante M Souques F Deschamps G Ostiguy J Lambrozo A W Thomas A Legros Human Threshold Research Group - Bioelectromagnetics Imaging Program Lawson Health Research Institute London ON N6A 4V2 Canada School of Kinesiology Western University London ON N6A 3K7 Canada Department of Medical Biophysics Western University London ON N6A 3K7 Canada Hydro-Québec Montreal QC H2Z 1A4 Canada Service des études médicales EDF Paris France Service Environnement Réseaux RTE Paris France Department of Medical Imaging Western University London ON N6A 3K7 Canada To whom any correspondence should be addressed.

Although studies have found that extremely low-frequency (ELF, < 300 Hz) magnetic fields (MF) can modulate human standing balance, the acute effects of electromagnetic fields on standing balance have not been systematically investigated. This work aims to establish the threshold for acute standing balance modulation during ELFMF exposure. One hundred volunteers will be exposed to transcranial electric stimulations (Direct current - DC and Alternating current - AC, 1 mA) and ELFMF (0 to 160 Hz, 0 to 100 mT). The displacement of their center of pressure will be collected and analyzed as an indicator of vestibular performance. During pilot testing (n=6), we found increased lateral sway with DC, and to a lesser extent, AC exposure. The ELFMF exposure system still needs to be adapted to allow meaningful results. Future protocol design will test for possible effects due to exposures in the radiofrequency range (i.e. above 3 kHz). These results will contribute to the literature documenting exposure guidelines aiming to protect workers and the general public.

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The Role of Margin in Link design and Optimization

The Role of Margin in Link Design and Optimization

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IEEE Aerospace conference

作者： K. Cheung Jet Propulsion Laboratory

ISBN: (纸本)9781479953813

Link analysis is a system engineering process in the design, development, and operation of communication systems and networks. Link models that are mathematical abstractions representing the useful signal power and the undesirable noise and attenuation effects (including weather effects if the signal path transverses through the atmosphere) that are integrated into the link budget calculation that provides the estimates of signal power and noise power at the receiver. Then the link margin is applied which attempts to counteract the fluctuations of the signal and noise power to ensure reliable data delivery from transmitter to receiver. (Link margin is dictated by the link margin policy or requirements.) A simple link budgeting approach assumes link parameters to be deterministic values typically adopted a rule-of-thumb policy of 3 dB link margin. This policy works for most S- and X-band links due to their insensitivity to weather effects. But for higher frequency links like Ka-band, Ku-band, and optical communication links, it is unclear if a 3 dB link margin would guarantee link closure. Statistical link analysis that adopted the 2-σ or 3-σ link margin incorporates link uncertainties in the σ calculation. (The Deep Space Network (DSN) link margin policies are 2-σ for downlink and 3-σ for uplink.) The link reliability can therefore be quantified statistically even for higher frequency links. However in the current statistical link analysis approach, link reliability is only expressed as the likelihood of exceeding the signal-to-noise ratio (SNR) threshold that corresponds to a given bit-error-rate (BER) or frame-error-rate (FER) requirement. The method does not provide the true BER or FER estimate of the link with margin, or the required signal-to-noise ratio (SNR) that would meet the BER or FER requirement in the statistical sense. In this paper, we perform in-depth analysis on the relationship between BER/FER requirement, operating SNR, and coding performance curv

关键词： Signal to noise ratio Bit error rate Receivers Encoding Meteorology

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A Method for Selecting Affordable System Concepts: A Case Application to Naval Ship design

A Method for Selecting Affordable System Concepts: A Case Ap...

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conference on Systems engineering Research

作者： Schaffner, Michael A. Ross, Adam M. Rhodes, Donna H. MIT SEAri Cambridge MA 02139 USA

The current defense acquisition environment includes much uncertainty regarding future budgets, political developments, and global geopolitical events. With affordability of systems now mandated by the US Department of Defense, it is imperative to ensure that future acquisitions will be feasible from their inception given resource considerations, and can remain feasible given various future perturbations of those resources. This paper introduces a method for early conceptual development (inception) of major defense systems and demonstrates the method's application to a case study of a hypothetical naval ship acquisition. The results of the application and the implications of the method for system development are discussed. (C) 2014 The Authors. Published by Elsevier B.v.

关键词： affordability systems engineering tradespace exploration utility expense epoch era

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Proof-of-concept demonstration of a miniaturized multi-resolution refocusing imaging system using an electrically tunable lens 15

Proof-of-concept demonstration of a miniaturized multi-resol...

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conference on current developments in Lens design and optical engineering Xv

作者： Smeesters, L. Belay, G. Y. Ottevaere, H. Meuret, Y. vervaeke, M. van Erps, J. Thienpont, H. Vrije Univ Brussel Fac Engn Dept Appl Phys & Photon TONA Brussels Photon Team B PHOT B-1050 Brussels Belgium

ISBN: (纸本)9781628412192

Refocusing multi-channel imaging systems are nowadays commercially available only in bulky and expensive designs. Compact wafer-level multi-channel imaging systems have until now only been published without refocusing mechanisms, since classical refocusing concepts could not be integrated in a miniaturized configuration. This lack of refocusing capabilities limits the depth-of-field of these imaging designs and therefore their application in practical systems. We designed and characterized a wafer-level two-channel multi-resolution refocusing imaging system, based on an electrically tunable liquid lens and a design that can be realized with wafer-level mass-manufacturing techniques. One wide field-of-view channel (2x40 degrees) gives a general image of the surroundings with a lower angular resolution (0.078 degrees), whereas the high angular resolution channel (0.0098 degrees) provides a detailed image of a small region of interest with a much narrower field-of-view (2x7.57 degrees). The latter high resolution imaging channel contains the tunable lens and therefore the refocusing capability. The performances of this high resolution imaging channel were experimentally characterized in a proof-of-concept demonstrator. The experimental and simulated depth-of-field and resolving power correspond well. Moreover, we are able to obtain a depth-of-field from 0.25m until infinity, which is a significant improvement of the current state-of-the-art static multi-channel imaging systems, which show a depth-of-field from 9m until infinity. Both the high resolution and wide field-of-view imaging channels show a diffraction-limited image quality. The designed wafer-level two-channel imaging system can form the basis of an advanced three-dimensional stacked image sensor, where different image processing algorithms can be simultaneously applied to the different images on the image sensor.

关键词： lens system design adaptive optics tunable lens refocusing imaging systems modulation transfer function miniature camera optics proof-of-concept demonstration

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