WorldWideScience

Sample records for optics parameters connection

  1. An optical system for controlling ion source parameters

    International Nuclear Information System (INIS)

    Zhang Baifang; Liu Zhenhao; Jiang Yi; Xu Zhengjia

    1999-01-01

    An optical control system used for adjusting the source's parameters of an ion separator is described. There are two slice microcomputers at HV terminal and the ground respectively. These microcomputers communicate each other with the full-duplex mode through two pieces of optical fiber, in which many parameters are time-share transmitted in the form of optical pulse. This system can stabilize the arc current and temperature, adjust and display all parameters and has safe-guard ability. At HV terminal, the optical coupling technique is used for connecting the CPU and the ion source, and at the ground the CPU can communicate with a control microcomputer

  2. Functional connectivity of the rodent brain using optical imaging

    Science.gov (United States)

    Guevara Codina, Edgar

    The aim of this thesis is to apply functional connectivity in a variety of animal models, using several optical imaging modalities. Even at rest, the brain shows high metabolic activity: the correlation in slow spontaneous fluctuations identifies remotely connected areas of the brain; hence the term "functional connectivity". Ongoing changes in spontaneous activity may provide insight into the neural processing that takes most of the brain metabolic activity, and so may provide a vast source of disease related changes. Brain hemodynamics may be modified during disease and affect resting-state activity. The thesis aims to better understand these changes in functional connectivity due to disease, using functional optical imaging. The optical imaging techniques explored in the first two contributions of this thesis are Optical Imaging of Intrinsic Signals and Laser Speckle Contrast Imaging, together they can estimate the metabolic rate of oxygen consumption, that closely parallels neural activity. They both have adequate spatial and temporal resolution and are well adapted to image the convexity of the mouse cortex. In the last article, a depth-sensitive modality called photoacoustic tomography was used in the newborn rat. Optical coherence tomography and laminar optical tomography were also part of the array of imaging techniques developed and applied in other collaborations. The first article of this work shows the changes in functional connectivity in an acute murine model of epileptiform activity. Homologous correlations are both increased and decreased with a small dependence on seizure duration. These changes suggest a potential decoupling between the hemodynamic parameters in resting-state networks, underlining the importance to investigate epileptic networks with several independent hemodynamic measures. The second study examines a novel murine model of arterial stiffness: the unilateral calcification of the right carotid. Seed-based connectivity analysis

  3. Identifying the connective strength between model parameters and performance criteria

    Directory of Open Access Journals (Sweden)

    B. Guse

    2017-11-01

    Full Text Available In hydrological models, parameters are used to represent the time-invariant characteristics of catchments and to capture different aspects of hydrological response. Hence, model parameters need to be identified based on their role in controlling the hydrological behaviour. For the identification of meaningful parameter values, multiple and complementary performance criteria are used that compare modelled and measured discharge time series. The reliability of the identification of hydrologically meaningful model parameter values depends on how distinctly a model parameter can be assigned to one of the performance criteria. To investigate this, we introduce the new concept of connective strength between model parameters and performance criteria. The connective strength assesses the intensity in the interrelationship between model parameters and performance criteria in a bijective way. In our analysis of connective strength, model simulations are carried out based on a latin hypercube sampling. Ten performance criteria including Nash–Sutcliffe efficiency (NSE, Kling–Gupta efficiency (KGE and its three components (alpha, beta and r as well as RSR (the ratio of the root mean square error to the standard deviation for different segments of the flow duration curve (FDC are calculated. With a joint analysis of two regression tree (RT approaches, we derive how a model parameter is connected to different performance criteria. At first, RTs are constructed using each performance criterion as the target variable to detect the most relevant model parameters for each performance criterion. Secondly, RTs are constructed using each parameter as the target variable to detect which performance criteria are impacted by changes in the values of one distinct model parameter. Based on this, appropriate performance criteria are identified for each model parameter. In this study, a high bijective connective strength between model parameters and performance criteria

  4. Performance Parameters for Grid-Connected PV Systems

    Energy Technology Data Exchange (ETDEWEB)

    Marion, B.; Adelstein, J.; Boyle, K.; Hayden, H.; Hammond, B.; Fletcher, T.; Canada, B.; Narang, D.; Shugar, D.; Wenger, H.; Kimber, A.; Mitchell, L.; Rich, G.; Townsend, T.

    2005-02-01

    The use of appropriate performance parameters facilitates the comparison of grid-connected photovoltaic (PV) systems that may differ with respect to design, technology, or geographic location. Four performance parameters that define the overall system performance with respect to the energy production, solar resource, and overall effect of system losses are the following: final PV system yield, reference yield, performance ratio, and PVUSA rating. These performance parameters are discussed for their suitability in providing desired information for PV system design and performance evaluation and are demonstrated for a variety of technologies, designs, and geographic locations. Also discussed are methodologies for determining system a.c. power ratings in the design phase using multipliers developed from measured performance parameters.The use of appropriate performance parameters facilitates the comparison of grid-connected photovoltaic (PV) systems that may differ with respect to design, technology, or geographic location. Four performance parameters that define the overall system performance with respect to the energy production, solar resource, and overall effect of system losses are the following: final PV system yield, reference yield, performance ratio, and PVUSA rating. These performance parameters are discussed for their suitability in providing desired information for PV system design and performance evaluation and are demonstrated for a variety of technologies, designs, and geographic locations. Also discussed are methodologies for determining system a.c. power ratings in the design phase using multipliers developed from measured performance parameters.

  5. Crosstalk performance of integrated optical cross-connects

    NARCIS (Netherlands)

    Herben, C.G.P.; Leijtens, X.J.M.; Maat, D.H.P.; Blok, H.; Smit, M.K.

    1999-01-01

    Crosstalk performance of monolithically integrated multiwavelength optical cross-connects (OXC's) depends strongly on their architecture. In this paper, a semiquantitative analysis of crosstalk in 11 different architectures is presented. Two architectures are analyzed numerically in more detail and

  6. Optical wireless connected objects for healthcare.

    Science.gov (United States)

    Toumieux, Pascal; Chevalier, Ludovic; Sahuguède, Stéphanie; Julien-Vergonjanne, Anne

    2015-10-01

    In this Letter the authors explore the communication capabilities of optical wireless technology for a wearable device dedicated to healthcare application. In an indoor environment sensible to electromagnetic perturbations such as a hospital, the use of optical wireless links can permit reducing the amount of radio frequencies in the patient environment. Moreover, this technology presents the advantage to be secure, low-cost and easy to deploy. On the basis of commercially available components, a custom-made wearable device is presented, which allows optical wireless transmission of accelerometer data in the context of physical activity supervision of post-stroke patients in hospital. Considering patient mobility, the experimental performance is established in terms of packet loss as a function of the number of receivers fixed to the ceiling. The results permit to conclude that optical wireless links can be used to perform such mobile remote monitoring applications. Moreover, based on the measurements obtained with one receiver, it is possible to theoretically determine the performance according to the number of receivers to be deployed.

  7. An Examination Of Fracture Splitting Parameters Of Crackable Connecting Rods

    Directory of Open Access Journals (Sweden)

    Zafer Özdemir

    2000-06-01

    Full Text Available Fracture splitting method is an innovative processing technique in the field of automobile engine connecting rod (con/rod manufacturing. Compared with traditional method, this technique has remarkable advantages. Manufacturing procedures, equipment and tools investment can be decreased and energy consumption reduced remarkably. Furthermore, product quality and bearing capability can also be improved. It provides a high quality, high accuracy and low cost route for producing connecting rods (con/rods. With the many advantages mentioned above, this method has attracted manufacturers attention and has been utilized in many types of con/rod manufacturing. In this article, the method and the advantages it provides, such as materials, notches for fracture splitting, fracture splitting conditions and fracture splitting equipment are discussed in detail. The paper describes an analysis of examination of fracture splitting parameters and optik-SEM fractography of C70S6 crackable connectıng rod. Force and velocity parameters are investigated. That uniform impact force distrubition starting from the starting notch causes brittle and cleavage failure mode is obtained as a result. This induces to decrease the toughness.

  8. Emerging Connections: Quantum & Classical Optics Incubator Program Book

    Energy Technology Data Exchange (ETDEWEB)

    Lesky, Marcia [Optical Society of America, Washington, DC (United States)

    2016-11-06

    The Emerging Connections: Quantum & Classical Optics Incubator was a scientific meeting held in Washington, DC on 6-8 November 2016. This Incubator provided unique and focused experiences and valuable opportunities to discuss advances, challenges and opportunities regarding this important area of research. Quantum optics and classical optics have coexisted for nearly a century as two distinct, but consistent descriptions of light in their respective domains. Recently, a number of detailed examinations of the structure of classical light beams have revealed that effects widely thought to be solely quantum in origin also have a place in classical optics. These new quantum-classical connections are informing classical optics in meaningful ways specifically by expanding understanding of optical coherence. Simultaneously, relationships discovered with classical light beams now also serve as a vehicle to illuminate concepts that no longer solely belong to the quantum realm. Interference, polarization, coherence, complementarity and entanglement are a partial list of elementary notions that now appear to belong to both quantum and classical optics. The goal of this meeting was to bring emerging quantum-classical links into wider view and to indicate directions in which forthcoming and future work would promote discussion and lead to a more unified understanding of optics.

  9. Optical Bloch equations with multiply connected states

    International Nuclear Information System (INIS)

    Stacey, D N; Lucas, D M; Allcock, D T C; Szwer, D J; Webster, S C

    2008-01-01

    The optical Bloch equations, which give the time evolution of the elements of the density matrix of an atomic system subject to radiation, are generalized so that they can be applied when transitions between pairs of states can proceed by more than one stimulated route. The case considered is that for which the time scale of interest in the problem is long compared with that set by the differences in detuning of the radiation fields stimulating via the different routes. It is shown that the Bloch equations then reduce to the standard form of linear differential equations with constant coefficients. The theory is applied to a two-state system driven by two lasers with different intensities and frequencies and to a three-state Λ-system with one laser driving one transition and two driving the second. It is also shown that the theory reproduces well the observed response of a cold 40 Ca + ion when subject to a single laser frequency driving the 4S 1/2 -4P 1/2 transition and a laser with two strong sidebands driving 3D 3/2 -4P 1/2

  10. Planar Large Core Polymer Optical 1x2 and 1x4 Splitters Connectable to Plastic Optical Fiber

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2013-09-01

    Full Text Available We report about new approach to design and fabricate multimode 1 x 2 and 1 x 4 Y optical planar power splitter suitable for low-cost short distance optical network. The splitters were designed by beam propagation method using BeamPROP™ software. The dimensions of the splitters were optimized for connecting standard plastic optical fibre with 1 mm diameter. New Norland Optical Adhesives 1625 glues were used as optical waveguide layers and the design structures were completed by CNC engraving on poly(methyl methacrylate substrate. The best parameters that were achieved with 1x2 splitter were insertion loss around 4.1dB at 650 nm and the coupling ratio 52:48; the best one of the 1x4 splitters had at 650 nm insertion loss around 17.6 dB.

  11. Performance of highly connected photonic switching lossless metro-access optical networks

    Science.gov (United States)

    Martins, Indayara Bertoldi; Martins, Yara; Barbosa, Felipe Rudge

    2018-03-01

    The present work analyzes the performance of photonic switching networks, optical packet switching (OPS) and optical burst switching (OBS), in mesh topology of different sizes and configurations. The "lossless" photonic switching node is based on a semiconductor optical amplifier, demonstrated and validated with experimental results on optical power gain, noise figure, and spectral range. The network performance was evaluated through computer simulations based on parameters such as average number of hops, optical packet loss fraction, and optical transport delay (Am). The combination of these elements leads to a consistent account of performance, in terms of network traffic and packet delivery for OPS and OBS metropolitan networks. Results show that a combination of highly connected mesh topologies having an ingress e-buffer present high efficiency and throughput, with very low packet loss and low latency, ensuring fast data delivery to the final receiver.

  12. Optical properties of electrically connected plasmonic nanoantenna dimer arrays

    Science.gov (United States)

    Zimmerman, Darin T.; Borst, Benjamin D.; Carrick, Cassandra J.; Lent, Joseph M.; Wambold, Raymond A.; Weisel, Gary J.; Willis, Brian G.

    2018-02-01

    We fabricate electrically connected gold nanoantenna arrays of homodimers and heterodimers on silica substrates and present a systematic study of their optical properties. Electrically connected arrays of plasmonic nanoantennas make possible the realization of novel photonic devices, including optical sensors and rectifiers. Although the plasmonic response of unconnected arrays has been studied extensively, the present study shows that the inclusion of nanowire connections modifies the device response significantly. After presenting experimental measurements of optical extinction for unconnected dimer arrays, we compare these to measurements of dimers that are interconnected by gold nanowire "busbars." The connected devices show the familiar dipole response associated with the unconnected dimers but also show a second localized surface plasmon resonance (LSPR) that we refer to as the "coupled-busbar mode." Our experimental study also demonstrates that the placement of the nanowire along the antenna modifies the LSPR. Using finite-difference time-domain simulations, we confirm the experimental results and investigate the variation of dimer gap and spacing. Changing the dimer gap in connected devices has a significantly smaller effect on the dipole response than it does in unconnected devices. On the other hand, both LSPR modes respond strongly to changing the spacing between devices in the direction along the interconnecting wires. We also give results for the variation of E-field strength in the dimer gap, which will be important for any working sensor or rectenna device.

  13. Scaling of the optical parameters for the JAERI tandem accelerator

    International Nuclear Information System (INIS)

    Hanashima, S.; Minehara, E.

    1986-01-01

    A scaling rule of the beam optical parameters was adopted for computer-aided beam transport in the JAERI tandem accelerator. Tests have shown that the computer program can transport a specified beam in a short time using a reference parameter set. Problems of ion source control and accuracy of the optical devices are also discussed

  14. Achievable qualitative parameters of optical wireless links

    Czech Academy of Sciences Publication Activity Database

    Kolka, Z.; Wilfert, O.; Fišer, Ondřej

    2007-01-01

    Roč. 9, č. 8 (2007), s. 2419-2423 ISSN 1454-4164 R&D Projects: GA ČR(CZ) GA102/05/0571 Institutional research plan: CEZ:AV0Z30420517 Keywords : Free-space optical link * Transmission of atmosphere * Optical communication Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.827, year: 2007 http://inoe.inoe.ro/joam/index.php?option=magazine&op=view&idu=838&catid=16

  15. Calculation of Optical Parameters of Liquid Crystals

    Science.gov (United States)

    Kumar, A.

    2007-12-01

    Validation of a modified four-parameter model describing temperature effect on liquid crystal refractive indices is being reported in the present article. This model is based upon the Vuks equation. Experimental data of ordinary and extraordinary refractive indices for two liquid crystal samples MLC-9200-000 and MLC-6608 are used to validate the above-mentioned theoretical model. Using these experimental data, birefringence, order parameter, normalized polarizabilities, and the temperature gradient of refractive indices are determined. Two methods: directly using birefringence measurements and using Haller's extrapolation procedure are adopted for the determination of order parameter. Both approches of order parameter calculation are compared. The temperature dependences of all these parameters are discussed. A close agreement between theory and experiment is obtained.

  16. Macaque accessory optic system: II. Connections with the pretectum

    International Nuclear Information System (INIS)

    Baleydier, C.; Magnin, M.; Cooper, H.M.

    1990-01-01

    Connections of the accessory optic system (AOS) with the pretectum are described in the macaque monkey. Injections of tritiated amino acids in the pretectum demonstrate a major contralateral projection to the dorsal (DTN), lateral (LTN), and medial (MTN) terminal nuclei of the AOS and a sparser projection to the ipsilateral LTN. Injections of retrograde tracers, Fast Blue (FB), or wheat germ agglutinin horseradish peroxidase (WGA-HRP) plus nonconjugated horseradish peroxidase (HRP) in the LTN show that the pretectal-LTN projection originates from two nuclei. The main source of pretectal efferents to the LTN is from the pretectal olivary nucleus (OPN) and is entirely contralateral. This projection, which appears unique to primates, originates from the large multipolar cells of the OPN. In addition to this projection, the nucleus of the optic tract (NOT) projects to the ipsilateral LTN, as in nonprimates. Injection of WGA-HRP in the pretectum shows a reciprocal predominantely ipsilateral projection from the LTN to the pretectum. Retinas were observed after injection of FB in the LTN. The retinal ganglion cells projecting to the AOS are mainly distributed near the fovea and in the nasal region of the contralateral eye, suggesting a nasotemporal pattern of decussation. The demonstration of a direct connection between LTN and OPN forces to a reconsideration of the functional role of the AOS. Previous descriptions of luminance responsive cells in the LTN support a possible participation of this nucleus in the control of the pupillary light reflex

  17. Optical cross-connect circuit using hitless wavelength selective switch.

    Science.gov (United States)

    Goebuchi, Yuta; Hisada, Masahiko; Kato, Tomoyuki; Kokubun, Yasuo

    2008-01-21

    We have proposed and demonstrated the basic elements of a full matrix optical switching circuit (cross-connect circuit) using a hitless wavelength selective switch (WSS). The cross-connect circuits are made of a multi-wavelength channel selective switch consisting of cascaded hitless WSSs, and a multi-port switch. These switching elements are realized through the individual Thermo-Optic (TO) tuning of a series-coupled microring resonator, and can switch arbitrary wavelength channels without blocking other wavelength channels during tuning. We demonstrate a four wavelength selective switch using a parallel topology of double series coupled microring resonators and a three wavelength selective switch using a parallel topology of quadruple series coupled microring resonators. Since the spectrum shape of quadruple series coupled microring is much more box-like than the double series, a high extinction ratio of 39.0-46.6 dB and low switching cross talk of 19.3-24.5 dB were achieved.

  18. Design Parameter Variation of Highly Stressed, Bi-Conal Graphite Electrode Connections through Numerical Simulation

    National Research Council Canada - National Science Library

    Mohammed, Ali

    2000-01-01

    The dissertation delves into the mediation of change effects between geometrical and materially technical design parameters of graphite electrode connections and the optimization of their combinations...

  19. Genetic algorithm approach to thin film optical parameters determination

    International Nuclear Information System (INIS)

    Jurecka, S.; Jureckova, M.; Muellerova, J.

    2003-01-01

    Optical parameters of thin film are important for several optical and optoelectronic applications. In this work the genetic algorithm proposed to solve optical parameters of thin film values. The experimental reflectance is modelled by the Forouhi - Bloomer dispersion relations. The refractive index, the extinction coefficient and the film thickness are the unknown parameters in this model. Genetic algorithm use probabilistic examination of promissing areas of the parameter space. It creates a population of solutions based on the reflectance model and then operates on the population to evolve the best solution by using selection, crossover and mutation operators on the population individuals. The implementation of genetic algorithm method and the experimental results are described too (Authors)

  20. Connecting Global to Local Parameters in Barred Galaxy Models

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Key words. Galaxies: barred—orbits—global and local parameters. .... series near the stable Lagrange point L1, which coincides with the origin. Doing so, .... Toomre, A. 1981, In: The Structure and Evolution of Normal Galaxies, (eds) S. M. Fall,.

  1. Connecting Jacobi elliptic functions with different modulus parameters

    Indian Academy of Sciences (India)

    found in the literature do not involve any change in the modulus parameter m. For ... Here, the right-hand side contains the sum of two terms with arguments separated ...... able thing is that, it is precisely these sums for which Landen formulas, mentioned above ... ematical sciences (Springer-Verlag, New York, 1989) vol. 80.

  2. Fully reconfigurable 2x2 optical cross-connect using tunable wavelength switching modules

    DEFF Research Database (Denmark)

    Liu, Fenghai; Zheng, Xueyan; Pedersen, Rune Johan Skullerud

    2001-01-01

    A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels.......A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels....

  3. Prioritizing connection requests in GMPLS-controlled optical networks

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Koster, A.; Andriolli, N.

    2009-01-01

    We prioritize bidirectional connection requests by combining dynamic connection provisioning with off-line optimization. Results show that the proposed approach decreases wavelength-converter usage, thereby allowing operators to reduce blocking-probably under bulk connection assignment or network...

  4. Analysis of the optical parameters of phase holographic gratings

    Directory of Open Access Journals (Sweden)

    Є.О. Тихонов

    2008-03-01

    Full Text Available  Suitability of 2- wave approximation of the coupled waves theory tor description of holographic phase gratings recorded on photopolymer compound ФПК-488 is proved. Using the basic formulas of the theory, main grating optical parameters - a depth of modulation and finished thickness are not measured immediately are determined.

  5. Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sidek, S. [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia); Medical Imaging Unit, Faculty of Medicine, Universiti Teknologi MARA, Selangor (Malaysia); Ramli, N. [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia); Rahmat, K., E-mail: katt_xr2000@yahoo.com [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia); Ramli, N.M.; Abdulrahman, F. [Department of Ophthalmology, Faculty of Medicine, University Malaya, Kuala Lumpur (Malaysia); Tan, L.K. [Department of Biomedical Imaging, University Malaya, Research Imaging Centre, Faculty of Medicine, University Malaya (Malaysia)

    2014-08-15

    Objectives: To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness. Methods: 3-Tesla DTI was performed on 90 subjects (30 normal, 30 mild glaucoma and 30 severe glaucoma subjects) and the FA and MD of the optic nerve and optic radiation were measured. The categorisation into mild and severe glaucoma was done using the Hodapp–Parrish–Anderson (HPA) classification. RNFL thickness was also assessed on all subjects using OCT. Receiver operating characteristic (ROC) analysis and Spearman's correlation coefficient was carried out. Results: FA and MD values in the optic nerve and optic radiation decreased and increased respectively as the disease progressed. FA at the optic nerve had the highest sensitivity (87%) and specificity (80%). FA values displayed the strongest correlation with RNFL thickness in the optic nerve (r = 0.684, p ≤ 0.001) while MD at the optic radiation showed the weakest correlation with RNFL thickness (r = −0.360, p ≤ 0.001). Conclusions: The high sensitivity and specificity of DTI-derived FA values in the optic nerve and the strong correlation between DTI-FA and RNFL thickness suggest that these parameters could serve as indicators of disease severity.

  6. Glaucoma severity affects diffusion tensor imaging (DTI) parameters of the optic nerve and optic radiation

    International Nuclear Information System (INIS)

    Sidek, S.; Ramli, N.; Rahmat, K.; Ramli, N.M.; Abdulrahman, F.; Tan, L.K.

    2014-01-01

    Objectives: To evaluate whether MR diffusion tensor imaging (DTI) of the optic nerve and optic radiation in glaucoma patients provides parameters to discriminate between mild and severe glaucoma and to determine whether DTI derived indices correlate with retinal nerve fibre layer (RNFL) thickness. Methods: 3-Tesla DTI was performed on 90 subjects (30 normal, 30 mild glaucoma and 30 severe glaucoma subjects) and the FA and MD of the optic nerve and optic radiation were measured. The categorisation into mild and severe glaucoma was done using the Hodapp–Parrish–Anderson (HPA) classification. RNFL thickness was also assessed on all subjects using OCT. Receiver operating characteristic (ROC) analysis and Spearman's correlation coefficient was carried out. Results: FA and MD values in the optic nerve and optic radiation decreased and increased respectively as the disease progressed. FA at the optic nerve had the highest sensitivity (87%) and specificity (80%). FA values displayed the strongest correlation with RNFL thickness in the optic nerve (r = 0.684, p ≤ 0.001) while MD at the optic radiation showed the weakest correlation with RNFL thickness (r = −0.360, p ≤ 0.001). Conclusions: The high sensitivity and specificity of DTI-derived FA values in the optic nerve and the strong correlation between DTI-FA and RNFL thickness suggest that these parameters could serve as indicators of disease severity

  7. Quantum correction and ordering parameter for systems connected by a general point canonical transformation

    International Nuclear Information System (INIS)

    Yeon, Kyu Hwang; Hong, Suc Kyoung; Um, Chung In; George, Thomas F.

    2006-01-01

    With quantum operators corresponding to functions of the canonical variables, Schroedinger equations are constructed for systems corresponding to classical systems connected by a general point canonical transformation. Using the operator connecting quantum states between systems before and after the transformation, the quantum correction term and ordering parameter are obtained

  8. Capturing Revolute Motion and Revolute Joint Parameters with Optical Tracking

    Science.gov (United States)

    Antonya, C.

    2017-12-01

    Optical tracking of users and various technical systems are becoming more and more popular. It consists of analysing sequence of recorded images using video capturing devices and image processing algorithms. The returned data contains mainly point-clouds, coordinates of markers or coordinates of point of interest. These data can be used for retrieving information related to the geometry of the objects, but also to extract parameters for the analytical model of the system useful in a variety of computer aided engineering simulations. The parameter identification of joints deals with extraction of physical parameters (mainly geometric parameters) for the purpose of constructing accurate kinematic and dynamic models. The input data are the time-series of the marker’s position. The least square method was used for fitting the data into different geometrical shapes (ellipse, circle, plane) and for obtaining the position and orientation of revolute joins.

  9. Dome diagnostics system of optical parameters and characteristics of LEDs

    Science.gov (United States)

    Peretyagin, Vladimir S.; Pavlenko, Nikita A.

    2017-09-01

    Scientific and technological progress of recent years in the production of the light emitting diodes (LEDs) has led to the expansion of areas of their application from the simplest systems to high precision lighting devices used in various fields of human activity. However, development and production (especially mass production) of LED lighting devices are impossible without a thorough analysis of its parameters and characteristics. There are many ways and devices for analysis the spatial, energy and colorimetric parameters of LEDs. The most methods are intended for definition only one parameter (for example, luminous flux) or one characteristic (for example, the angular distribution of energy or the spectral characteristics). Besides, devices used these methods are intended for measuring parameters in only one point or plane. This problem can be solved by using a dome diagnostics system of optical parameters and characteristics of LEDs, developed by specialists of the department OEDS chair of ITMO University in Russia. The paper presents the theoretical aspects of the analysis of LED's spatial (angular), energy and color parameters by using mentioned of diagnostics system. The article also presents the results of spatial), energy and color parameters measurements of some LEDs brands.

  10. Parameter study on infilled steel frames with discretely connected precast concrete panels

    NARCIS (Netherlands)

    Teeuwen, P.A.; Kleinman, C.S.; Snijder, H.H.; Hofmeyer, H.; Chan, S.L.

    2009-01-01

    This paper presents a parameter study on infilled steel frames with discretely connected precast concrete infill panels having window openings. In this study, finite element simulations were carried out to study the infilled frame performance by varying several parameters. A recently developed

  11. Electro-optical parameters of bond polarizability model for aluminosilicates.

    Science.gov (United States)

    Smirnov, Konstantin S; Bougeard, Daniel; Tandon, Poonam

    2006-04-06

    Electro-optical parameters (EOPs) of bond polarizability model (BPM) for aluminosilicate structures were derived from quantum-chemical DFT calculations of molecular models. The tensor of molecular polarizability and the derivatives of the tensor with respect to the bond length are well reproduced with the BPM, and the EOPs obtained are in a fair agreement with available experimental data. The parameters derived were found to be transferable to larger molecules. This finding suggests that the procedure used can be applied to systems with partially ionic chemical bonds. The transferability of the parameters to periodic systems was tested in molecular dynamics simulation of the polarized Raman spectra of alpha-quartz. It appeared that the molecular Si-O bond EOPs failed to reproduce the intensity of peaks in the spectra. This limitation is due to large values of the longitudinal components of the bond polarizability and its derivative found in the molecular calculations as compared to those obtained from periodic DFT calculations of crystalline silica polymorphs by Umari et al. (Phys. Rev. B 2001, 63, 094305). It is supposed that the electric field of the solid is responsible for the difference of the parameters. Nevertheless, the EOPs obtained can be used as an initial set of parameters for calculations of polarizability related characteristics of relevant systems in the framework of BPM.

  12. Optic disc size and other parameters from optical coherence tomography in Vietnamese-Americans.

    Science.gov (United States)

    Peng, Pai-Huei; Fu, Sheena; Nguyen, Ngoc; Porco, Travis; Lin, Shan C

    2011-08-01

    To investigate the optic disc parameters by optical coherence tomography (OCT) in Vietnamese with various types of glaucoma. Medical charts of Vietnamese and White patients within a single practice were reviewed. Disc and rim areas by OCT were compared among nonglaucoma controls, different types of glaucoma, and glaucoma suspect. The association of these parameters with demographic and ocular features was evaluated. Data from 1416 Vietnamese and 57 White patients were included. A larger mean disc area was observed in eyes with primary angle-closure glaucoma than in eyes with primary angle-closure and primary angle-closure suspect (both PVietnamese patients with glaucoma and glaucoma suspicion had larger discs than diagnosis-matched Whites (P=0.043 and 0.021, respectively). Vietnamese patients with glaucoma seem to have larger optic discs than White patients. Central corneal thickness had no association with disc area in this study population.

  13. Performance of Series Connected GaAs Photovoltaic Converters under Multimode Optical Fiber Illumination

    Directory of Open Access Journals (Sweden)

    Tiqiang Shan

    2014-01-01

    Full Text Available In many military and industrial applications, GaAs photovoltaic (PV converters are connected in series in order to generate the required voltage compatible with most common electronics. Multimode optical fibers are usually used to carry high-intensity laser and illuminate the series connected GaAs PV converters in real time. However, multimode optical fiber illumination has a speckled intensity pattern. The series connected PV array is extremely sensitive to nonuniform illumination; its performance is limited severely by the converter that is illuminated the least. This paper quantifies the effects of multimode optical fiber illumination on the performance of series connected GaAs PV converters, analyzes the loss mechanisms due to speckles, and discusses the maximum illumination efficiency. In order to describe the illumination dependent behavior detailedly, modeling of the series connected PV array is accomplished based on the equivalent circuit for PV cells. Finally, a series of experiments are carried out to demonstrate the theory analysis.

  14. Optical Fiber Connection Navigation System Using Visible Light Communication in Central Office with Economic Evaluation

    Science.gov (United States)

    Waki, Masaki; Uruno, Shigenori; Ohashi, Hiroyuki; Manabe, Tetsuya; Azuma, Yuji

    We propose an optical fiber connection navigation system that uses visible light communication for an integrated distribution module in a central office. The system realizes an accurate database, requires less skilled work to operate and eliminates human error. This system can achieve a working time reduction of up to 88.0% compared with the conventional work without human error for the connection/removal of optical fiber cords, and is economical as regards installation and operation.

  15. Identification of Synchronous Generator Electric Parameters Connected to the Distribution Grid

    Directory of Open Access Journals (Sweden)

    Frolov M. Yu.

    2017-04-01

    Full Text Available According to modern trends, the power grids with distributed generation will have an open system architecture. It means that active consumers, owners of distributed power units, including mobile units, must have free access to the grid, like when using internet, so it is necessary to have plug and play technologies. Thanks to them, the system will be able to identify the unit type and the unit parameters. Therefore, the main aim of research, described in the paper, was to develop and research a new method of electric parameters identification of synchronous generator. The main feature of the proposed method is that parameter identification is performed while the generator to the grid, so it fits in the technological process of operation of the machine and does not influence on the connection time of the machine. For the implementation of the method, it is not necessary to create dangerous operation modes for the machine or to have additional expensive equipment and it can be used for salient pole machines and round rotor machines. The parameter identification accuracy can be achieved by more accurate account of electromechanical transient process, and making of overdetermined system with many more numbers of equations. Parameter identification will be made with each generator connection to the grid. Comparing data obtained from each connection, the middle values can be find by numerical method, and thus, each subsequent identification will accurate the machine parameters.

  16. Correlation characteristics of optical coherence tomography images of turbid media with statistically inhomogeneous optical parameters

    International Nuclear Information System (INIS)

    Dolin, Lev S.; Sergeeva, Ekaterina A.; Turchin, Ilya V.

    2012-01-01

    Noisy structure of optical coherence tomography (OCT) images of turbid medium contains information about spatial variations of its optical parameters. We propose analytical model of statistical characteristics of OCT signal fluctuations from turbid medium with spatially inhomogeneous coefficients of absorption and backscattering. Analytically predicted correlation characteristics of OCT signal from spatially inhomogeneous medium are in good agreement with the results of correlation analysis of OCT images of different biological tissues. The proposed model can be efficiently applied for quantitative evaluation of statistical properties of absorption and backscattering fluctuations basing on correlation characteristics of OCT images.

  17. Modelling of bio-optical parameters of open ocean waters

    Directory of Open Access Journals (Sweden)

    Vadim N. Pelevin

    2001-12-01

    Full Text Available An original method for estimating the concentration of chlorophyll pigments, absorption of yellow substance and absorption of suspended matter without pigments and yellow substance in detritus using spectral diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance data has been applied to sea waters of different types in the open ocean (case 1. Using the effective numerical single parameter classification with the water type optical index m as a parameter over the whole range of the open ocean waters, the calculations have been carried out and the light absorption spectra of sea waters tabulated. These spectra are used to optimize the absorption models and thus to estimate the concentrations of the main admixtures in sea water. The value of m can be determined from direct measurements of the downward irradiance attenuation coefficient at 500 nm or calculated from remote sensing data using the regressions given in the article. The sea water composition can then be readily estimated from the tables given for any open ocean area if that one parameter m characterizing the basin is known.

  18. An efficient optical architecture for sparsely connected neural networks

    Science.gov (United States)

    Hine, Butler P., III; Downie, John D.; Reid, Max B.

    1990-01-01

    An architecture for general-purpose optical neural network processor is presented in which the interconnections and weights are formed by directing coherent beams holographically, thereby making use of the space-bandwidth products of the recording medium for sparsely interconnected networks more efficiently that the commonly used vector-matrix multiplier, since all of the hologram area is in use. An investigation is made of the use of computer-generated holograms recorded on such updatable media as thermoplastic materials, in order to define the interconnections and weights of a neural network processor; attention is given to limits on interconnection densities, diffraction efficiencies, and weighing accuracies possible with such an updatable thin film holographic device.

  19. Secchi depth analysis using bio-optical parameters measured in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Naik, P.; Bandishte, M.; Desa, E.; Mascarenhas, A.A.M.Q.; Matondkar, S.G.P.

    spatial and temporal variability of Secchi depth and their dependence on the optical properties beam attenuation and diffuse attenuation the biological parameter of Chlorophyll. The in-situ measured inherent and apparent optical properties have been used...

  20. Flow-cytometric identification of vinegars using a multi-parameter analysis optical detection module

    Science.gov (United States)

    Verschooten, T.; Ottevaere, H.; Vervaeke, M.; Van Erps, J.; Callewaert, M.; De Malsche, W.; Thienpont, H.

    2015-09-01

    We show a proof-of-concept demonstration of a multi-parameter analysis low-cost optical detection system for the flowcytometric identification of vinegars. This multi-parameter analysis system can simultaneously measure laser induced fluorescence, absorption and scattering excited by two time-multiplexed lasers of different wavelengths. To our knowledge no other polymer optofluidic chip based system offers more simultaneous measurements. The design of the optofluidic channels is aimed at countering the effects that viscous fingering, air bubbles, and emulsion samples can have on the correct operation of such a detection system. Unpredictable variations in viscosity and refractive index of the channel content can be turned into a source of information. The sample is excited by two laser diodes that are driven by custom made low-cost laser drivers. The optofluidic chip is built to be robust and easy to handle and is reproducible using hot embossing. We show a custom optomechanical holder for the optofluidic chip that ensures correct alignment and automatic connection to the external fluidic system. We show an experiment in which 92 samples of vinegar are measured. We are able to identify 9 different kinds of vinegar with an accuracy of 94%. Thus we show an alternative approach to the classic optical spectroscopy solution at a lowered. Furthermore, we have shown the possibility of predicting the viscosity and turbidity of vinegars with a goodness-of-fit R2 over 0.947.

  1. Soil structure interaction model and variability of parameters in seismic analysis of nuclear island connected building

    International Nuclear Information System (INIS)

    Subramanian, K.V.; Palekar, S.M.; Bavare, M.S.; Mapari, H.A.; Patel, S.C.; Pillai, C.S.

    2005-01-01

    This paper provides salient features of the Soil Structure Interaction analysis of Nuclear Island Connected Building (NICB). The dynamic analysis of NICB is performed on a full 3D model accounting for the probable variation in the stiffness of the founding medium. A range analyses was performed to establish the effect of variability of subgrade parameters on the results of seismic analyses of NICB. This paper presents details of various analyses with respect to the subgrade model, uncertainties in subgrade properties, results of seismic analyses and a study of effect of the variability of parameters on the results of these analyses. The results of this study indicate that the variability of soil parameters beyond a certain value of shear wave velocity does not influence the response and in fact the response marginally diminishes. (authors)

  2. Brain connectivity study of joint attention using frequency-domain optical imaging technique

    Science.gov (United States)

    Chaudhary, Ujwal; Zhu, Banghe; Godavarty, Anuradha

    2010-02-01

    Autism is a socio-communication brain development disorder. It is marked by degeneration in the ability to respond to joint attention skill task, from as early as 12 to 18 months of age. This trait is used to distinguish autistic from nonautistic populations. In this study, diffuse optical imaging is being used to study brain connectivity for the first time in response to joint attention experience in normal adults. The prefrontal region of the brain was non-invasively imaged using a frequency-domain based optical imager. The imaging studies were performed on 11 normal right-handed adults and optical measurements were acquired in response to joint-attention based video clips. While the intensity-based optical data provides information about the hemodynamic response of the underlying neural process, the time-dependent phase-based optical data has the potential to explicate the directional information on the activation of the brain. Thus brain connectivity studies are performed by computing covariance/correlations between spatial units using this frequency-domain based optical measurements. The preliminary results indicate that the extent of synchrony and directional variation in the pattern of activation varies in the left and right frontal cortex. The results have significant implication for research in neural pathways associated with autism that can be mapped using diffuse optical imaging tools in the future.

  3. Assessment of detection limits of fiber-optic distributed temperature sensing for detection of illicit connections

    NARCIS (Netherlands)

    Nienhuis, J.; De Haan, C.; Langeveld, J.G.; Klootwijk, M.; Clemens, F.H.L.R.

    2012-01-01

    Distributed Temperature Sensing (DTS) with fiber-optic cables is a powerful tool to detect illicit connections in storm sewer systems. High frequency temperature measurements along the in-sewer cable create a detailed representation of temperature anomalies due to illicit discharges. The detection

  4. Network analysis of mesoscale optical recordings to assess regional, functional connectivity.

    Science.gov (United States)

    Lim, Diana H; LeDue, Jeffrey M; Murphy, Timothy H

    2015-10-01

    With modern optical imaging methods, it is possible to map structural and functional connectivity. Optical imaging studies that aim to describe large-scale neural connectivity often need to handle large and complex datasets. In order to interpret these datasets, new methods for analyzing structural and functional connectivity are being developed. Recently, network analysis, based on graph theory, has been used to describe and quantify brain connectivity in both experimental and clinical studies. We outline how to apply regional, functional network analysis to mesoscale optical imaging using voltage-sensitive-dye imaging and channelrhodopsin-2 stimulation in a mouse model. We include links to sample datasets and an analysis script. The analyses we employ can be applied to other types of fluorescence wide-field imaging, including genetically encoded calcium indicators, to assess network properties. We discuss the benefits and limitations of using network analysis for interpreting optical imaging data and define network properties that may be used to compare across preparations or other manipulations such as animal models of disease.

  5. Transmission enhancement by deployment of interferometric wavelength converters within all-optical cross connects

    DEFF Research Database (Denmark)

    Poulsen, Henrik Nørskov; Mikkelsen, Benny; Stubkjær, Kristian

    1997-01-01

    Wavelength-division multiplexing (WDM) networks are expected to utilize all-optical cross connects (OXCN) for signal routing. Because a signal path is likely to contain a number of OXCNs, their cascadability is essential. Furthermore, because wavelength converters in the OXCNs improve traffic...

  6. Marine parameters from synergy of optical and radar satellite data

    Science.gov (United States)

    Lehner, S.; Hoja, D.; Schulz-Stellenfleth, J.

    In 2001 the European Space Agency ESA will launch the earth observation satellite ENVISAT. It will carry several instruments that provide new opportunities to measure oceanographic variables. Together, they represent the main measurement techniques of satellite oceanography, and complement each other in an ideal manner. These instruments are to be used in synergy to: Improve the analysis of measured wind and ocean wave fields, and thereby improve weather forecasting at weather centers; Determine the extent and variables of sea ice and develop a five-day sea ice prediction model, to support maritime shipping and offshore activities; Monitor and map sediment and suspended matter transport in coastal regions, especially in areas with large river estuaries, which greatly affects shipping lanes, harbors, and dredging activities; Monitor hydrobiological and bio-geochemical variables related to water quality in coastal regions and large inland waters, which affects ecology, coastal development, aquaculture, drinking water supplies, and tourism. To prepare the oceanographic community to make best use of the ENVISAT sensors in the pre-launch phase, existing algorithms to derive marine parameters are used and validated using data from the ERS SAR, the ERS RA, SeaWiFS and IRS MOS sensors now in operation. Derived products are used to address problems that can best be tackled using the synergy of radar and optical data, such as the effect of surface slicks on radar wind measurements, of sea state on ocean color, of wind and waves on the resuspension of suspended matter, and of wind and waves on sea ice variables.

  7. Variations of aerosol optical depth and Angstrom parameters at a ...

    Indian Academy of Sciences (India)

    In this paper, aerosol optical properties including aerosol optical depth (AOD), Angstrom exponent () and Angstrom turbidity coefficient () have been investigated during December 2009 to October 2010, in a suburban area of Zanjan (36°N, 43°E, 1700 m), in the north–west of Iran, using meteorological and sun ...

  8. Electro-Optical Parameters Of Hairy Rod Polymer/Dimethylformamide System

    International Nuclear Information System (INIS)

    Spasevska, Hristina

    2003-01-01

    Rigid rod polymers are materials with special features, that is the reason why they have large scientific and technological applications like isotropic-nematic and other types of transition. One of the biggest problems that happen while investigation to these polymers, at molecular level, is their poor solubility in most of the common solvents. Solubility gets better if while synthesize junctions flexible side chains, [1]. Remaining polymers belong on one new class - hairy rod polymers and have big potential for their technological applications. Because of their nonlinear optical properties and opportunity for self-organization in super molecular structures (films and fibers), can be used in electronics and telecommunications industry either at display-technologies [2]. That is the main reason why controlling the remaining polymer features and connection of their microscopic and macroscopic characteristics, like an complete characterization (in solutions and solid state) is from essential scientific interest, actually it is an imperative. The polymer POD-2/that is subject of investigation, bellows to hairy rod polymers and it is synthesized for the first time [3] by giving a support to their characterization. Measures on diluted solutions from the system POD-2/dimethylformamide are made by the method electric birefringence, at three temperatures (25, 40 and 55 o C). For different concentrations on system, from obtained electro-optical signals (EOS), dependence on electric birefringence (Δn) against applied electric field (E 2 ), is determined. By investigation of electro-optical effects, especially studding the way of their maintenance and losing, while applying electric square impulses, relaxation time τ o of polymer molecules is calculated. From these parameters, as presented data for EOS rise and decay too, deformational electro-optical effect has been determined. (Author)

  9. PERFORMANCE ANALYSIS OF OPTICAL CDMA SYSTEM USING VC CODE FAMILY UNDER VARIOUS OPTICAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    HASSAN YOUSIF AHMED

    2012-06-01

    Full Text Available The intent of this paper is to study the performance of spectral-amplitude coding optical code-division multiple-access (OCDMA systems using Vector Combinatorial (VC code under various optical parameters. This code can be constructed by an algebraic way based on Euclidian vectors for any positive integer number. One of the important properties of this code is that the maximum cross-correlation is always one which means that multi-user interference (MUI and phase induced intensity noise are reduced. Transmitter and receiver structures based on unchirped fiber Bragg grating (FBGs using VC code and taking into account effects of the intensity, shot and thermal noise sources is demonstrated. The impact of the fiber distance effects on bit error rate (BER is reported using a commercial optical systems simulator, virtual photonic instrument, VPITM. The VC code is compared mathematically with reported codes which use similar techniques. We analyzed and characterized the fiber link, received power, BER and channel spacing. The performance and optimization of VC code in SAC-OCDMA system is reported. By comparing the theoretical and simulation results taken from VPITM, we have demonstrated that, for a high number of users, even if data rate is higher, the effective power source is adequate when the VC is used. Also it is found that as the channel spacing width goes from very narrow to wider, the BER decreases, best performance occurs at a spacing bandwidth between 0.8 and 1 nm. We have shown that the SAC system utilizing VC code significantly improves the performance compared with the reported codes.

  10. Extraction of optical scattering parameters and attenuation compensation in optical coherence tomography images of multi-layered tissue structures

    DEFF Research Database (Denmark)

    Thrane, Lars; Frosz, Michael Henoch; Tycho, Andreas

    2004-01-01

    A recently developed analytical optical coherence tomography (OCT) model [Thrane et al., J. Opt. Soc. Am. A 17, 484 (2000)] allows the extraction of optical scattering parameters from OCT images, thereby permitting attenuation compensation in those images. By expanding this theoretical model, we...... have developed a new method for extracting optical scattering parameters from multilayered tissue structures in vivo. To verify this, we used a Monte Carlo (MC) OCT model as a numerical phantom to simulate the OCT signal for het-erogeneous multilayered tissue. Excellent agreement between the extracted......, and the results hold promise for expanding the functional imaging capabilities of OCT....

  11. Extraction of optical parameters of thin films from spectral measurements for design and optical performance of multilayer structures

    International Nuclear Information System (INIS)

    Muellerova, J.; Jurecka, S.; Kucerova, A.

    2003-01-01

    Optical parameters of a-Si:H and indium tin oxide (ITO) thin films deposited on glass substrates are determined from spectral measurements of reflectance and/or transmittance. It is shown how important the exact knowledge of optical parameters as well as thicknesses of the layers for the design and the optical performance of multilayer structures is. The model of the p-i-n based a:Si-H solar cell with ITO as transparent conductive oxide layer is used for illustrating. The modeling of the solar cell integral reflectance in the spectral region of (650-830) nm is used as a criterion to reverse engineering of a multilayer structure with suppressed reflectance losses. The reflectance of a solar cell is modelled and the simulation of the varying optical parameters of individual layers including their thicknesses is discussed. Besides this,the advantage of using an antireflective layer under ITO is discussed (Authors)

  12. Optical spectral signatures of liquids by means of fiber optic technology for product and quality parameter identification

    Science.gov (United States)

    Mignani, A. G.; Ciaccheri, L.; Mencaglia, A. A.; Diaz-Herrera, N.; Garcia-Allende, P. B.; Ottevaere, H.; Thienpont, H.; Attilio, C.; Cimato, A.; Francalanci, S.; Paccagnini, A.; Pavone, F. S.

    2009-01-01

    Absorption spectroscopy in the wide 200-1700 nm spectral range is carried out by means of optical fiber instrumentation to achieve a digital mapping of liquids for the prediction of important quality parameters. Extra virgin olive oils from Italy and lubricant oils from turbines with different degrees of degradation were considered as "case studies". The spectral data were processed by means of multivariate analysis so as to obtain a correlation to quality parameters. In practice, the wide range absorption spectra were considered as an optical signature of the liquids from which to extract product quality information. The optical signatures of extra virgin olive oils were used to predict the content of the most important fatty acids. The optical signatures of lubricant oils were used to predict the concentration of the most important parameters for indicating the oil's degree of degradation, such as TAN, JOAP anti-wear index, and water content.

  13. Connection Management and Recovery Strategies under Epidemic Network Failures in Optical Transport Networks

    DEFF Research Database (Denmark)

    Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2014-01-01

    The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust...... manner under attacks. This work proposes four policies for failure handling in a connection-oriented optical transport network, under Generalized MultiProtocol Label Switching control plane, and evaluates their performance under multiple correlated large-scale failures. We employ the Susceptible...... of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50% less connections requiring recovery, which translates in improved quality of service to customers....

  14. Variations of aerosol optical depth and Angstrom parameters at a ...

    Indian Academy of Sciences (India)

    E, 1700 m), in the north–west of Iran, using meteorological and sun .... However, a few works have been carried out in the Middle-East region .... 3.1.2 Diurnal behaviour of AOD ... work, showed a prevailing pattern of the optical depth in which ...

  15. Multi-mode optical fibers for connecting space-based spectrometers

    Science.gov (United States)

    Roberts, W. T.; Lindenmisth, C. A.; Bender, S.; Miller, E. A.; Motts, E.; Ott, M.; LaRocca, F.; Thomes, J.

    2017-11-01

    significantly smaller, less massive and less robust. Large core multi-mode optical fibers are often used to accommodate the optical connection of the two separated portions of such instrumentation. In some cases, significant throughput efficiency improvement can be realized by judiciously orienting the strands of multi-fiber cable, close-bunching them to accommodate a tight focus of the optical system on the optical side of the connection, and splaying them out linearly along a spectrometer slit on the other end. For such instrumentation to work effectively in identifying elements and molecules, and especially to produce accurate quantitative results, the spectral throughput of the optical fiber connection must be consistent over varying temperatures, over the range of motion of the optical head (and it's implied optical cable stresses), and over angle-aperture invariant of the total system. While the first two of these conditions have been demonstrated[4], spectral observations of the latter present a cause for concern, and may have an impact on future design of fiber-connected LIBS and Raman spectroscopy instruments. In short, we have observed that the shape of the spectral efficiency curve of a large multi-mode core optical fiber changes as a function of input angle.

  16. A sensitivity analysis approach to optical parameters of scintillation detectors

    International Nuclear Information System (INIS)

    Ghal-Eh, N.; Koohi-Fayegh, R.

    2008-01-01

    In this study, an extended version of the Monte Carlo light transport code, PHOTRACK, has been used for a sensitivity analysis to estimate the importance of different wavelength-dependent parameters in the modelling of light collection process in scintillators

  17. Development of Single Optical Sensor Method for the Measurement Droplet Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ho; Ahn, Tae Hwan; Yun, Byong Jo [Pusan National University, Busan (Korea, Republic of); Bae, Byoung Uhn; Kim, Kyoung Doo [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, we tried to develop single optical fiber probe(S-TOP) sensor method to measure droplet parameters such as diameter, droplet fraction, and droplet velocity and so on. To calibrate and confirm the optical fiber sensor for those parameters, we conducted visualization experiments by using a high speed camera with the optical sensor. To evaluate the performance of the S-TOP accurately, we repeated calibration experiments at a given droplet flow condition. Figure. 3 shows the result of the calibration. In this graph, the x axis is the droplet velocity measured by visualization and the y axis is grd, D which is obtained from S-TOP. In this study, we have developed the single tip optical probe sensor to measure the droplet parameters. From the calibration experiments with high speed camera, we get the calibration curve for the droplet velocity. Additionally, the chord length distribution of droplets is measured by the optical probe.

  18. Development of Single Optical Sensor Method for the Measurement Droplet Parameters

    International Nuclear Information System (INIS)

    Kim, Tae Ho; Ahn, Tae Hwan; Yun, Byong Jo; Bae, Byoung Uhn; Kim, Kyoung Doo

    2016-01-01

    In this study, we tried to develop single optical fiber probe(S-TOP) sensor method to measure droplet parameters such as diameter, droplet fraction, and droplet velocity and so on. To calibrate and confirm the optical fiber sensor for those parameters, we conducted visualization experiments by using a high speed camera with the optical sensor. To evaluate the performance of the S-TOP accurately, we repeated calibration experiments at a given droplet flow condition. Figure. 3 shows the result of the calibration. In this graph, the x axis is the droplet velocity measured by visualization and the y axis is grd, D which is obtained from S-TOP. In this study, we have developed the single tip optical probe sensor to measure the droplet parameters. From the calibration experiments with high speed camera, we get the calibration curve for the droplet velocity. Additionally, the chord length distribution of droplets is measured by the optical probe.

  19. Analysis of the selected optical parameters of filters protecting against hazardous infrared radiation

    OpenAIRE

    Gralewicz, Grzegorz; Owczarek, Grzegorz

    2016-01-01

    The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filters provide more effective blocking of infrared radiation in comparison with the currently used protec...

  20. Performance emulation and parameter estimation for nonlinear fibre-optic links

    DEFF Research Database (Denmark)

    Piels, Molly; Porto da Silva, Edson; Zibar, Darko

    2016-01-01

    Fibre-optic communication systems, especially when operating in the nonlinear regime, generally do not perform exactly as theory would predict. A number of methods for data-based evaluation of nonlinear fibre-optic link parameters, both for accurate performance emulation and optimization...

  1. First Measurements of Higher Order Optics Parameters in the LHC

    CERN Document Server

    Vanbavinckhove, G; Bartolini, R; Calaga, R; Giovannozzi, M; Maclean, E H; Miyamoto, R; Schmidt, F; Tomas, R

    2011-01-01

    Higher order effects can play an important role in the performance of the LHC. Lack of knowledge of these pa- rameters can increase the tune footprint and compromise the beam lifetime. First measurements of these parameters at injection and flattop have been conducted. Detailed sim- ulations are compared to the measurements together with discussions on the measurement limitations.

  2. Quality parameters analysis of optical imaging systems with enhanced focal depth using the Wigner distribution function

    Science.gov (United States)

    Zalvidea; Colautti; Sicre

    2000-05-01

    An analysis of the Strehl ratio and the optical transfer function as imaging quality parameters of optical elements with enhanced focal length is carried out by employing the Wigner distribution function. To this end, we use four different pupil functions: a full circular aperture, a hyper-Gaussian aperture, a quartic phase plate, and a logarithmic phase mask. A comparison is performed between the quality parameters and test images formed by these pupil functions at different defocus distances.

  3. Multilayered analog optical differentiating device: performance analysis on structural parameters.

    Science.gov (United States)

    Wu, Wenhui; Jiang, Wei; Yang, Jiang; Gong, Shaoxiang; Ma, Yungui

    2017-12-15

    Analogy optical devices (AODs) able to do mathematical computations have recently gained strong research interest for their potential applications as accelerating hardware in traditional electronic computers. The performance of these wavefront-processing devices is primarily decided by the accuracy of the angular spectral engineering. In this Letter, we show that the multilayer technique could be a promising method to flexibly design AODs according to the input wavefront conditions. As examples, various Si-SiO 2 -based multilayer films are designed that can precisely perform the second-order differentiation for the input wavefronts of different Fourier spectrum widths. The minimum number and thickness uncertainty of sublayers for the device performance are discussed. A technique by rescaling the Fourier spectrum intensity has been proposed in order to further improve the practical feasibility. These results are thought to be instrumental for the development of AODs.

  4. Physiological Parameter Monitoring from Optical Recordings with a Mobile Phone

    Science.gov (United States)

    Scully, Christopher G.; Lee, Jinseok; Meyer, Joseph; Gorbach, Alexander M.; Granquist-Fraser, Domhnull; Mendelson, Yitzhak

    2012-01-01

    We show that a mobile phone can serve as an accurate monitor for several physiological variables, based on its ability to record and analyze the varying color signals of a fingertip placed in contact with its optical sensor. We confirm the accuracy of measurements of breathing rate, cardiac R-R intervals, and blood oxygen saturation, by comparisons to standard methods for making such measurements (respiration belts, ECGs, and pulse-oximeters, respectively). Measurement of respiratory rate uses a previously reported algorithm developed for use with a pulse-oximeter, based on amplitude and frequency modulation sequences within the light signal. We note that this technology can also be used with recently developed algorithms for detection of atrial fibrillation or blood loss. PMID:21803676

  5. Ring current and auroral electrojets in connection with interplanetary medium parameters during magnetic storm

    Directory of Open Access Journals (Sweden)

    Y. I. Feldstein

    1994-06-01

    Full Text Available The relationship between the auroral electrojet indices (AE and the ring current magnetic field (DR was investigated by observations obtained during the magnetic storm on 1-3 April 1973. During the storm main phase the DR development is accompanied by a shift of the auroral electrojets toward the equator. As a result, the standard AE indices calculated on the basis of data from auroral observatories was substantially lower than the real values (AE'. To determine AE' during the course of a storm main phase data from subauroral magnetic observatories should be used. It is shown that the intensity of the indices (AE' which take into account the shift of the electrojets is increased substantially relative to the standard indices during the storm main phase. AE' values are closely correlated with geoeffective solar wind parameters. A high correlation was obtained between AE' and the energy flux into the ring current during the storm main phase. Analysis of magnetic field variations during intervals with intense southward IMF components demonstrates a decrease of the saturation effect of auroral electrojet currents if subauroral stations magnetic field variations are taken into account. This applies both to case studies and statistical data. The dynamics of the electrojets in connection with the development of the ring current and of magnetospheric substorms can be described by the presence (absence of saturation for minimum (maximum AE index values during a 1-h interval. The ring current magnetic field asymmetry (ASY was calculated as the difference between the maximum and minimum field values along a parallel of latitude at low latitudes. The ASY value is closely correlated with geoeffective solar wind parameters and simultaneously is a more sensitive indicator of IMF Bz variations than the symmetric ring current. ASY increases (decreases faster during the main phase (the recovery phase than DR. The magnetic field decay at low latitudes in the

  6. Brain activation and connectivity of social cognition using diffuse optical imaging

    Science.gov (United States)

    Zhu, Banghe; Godavarty, Anuradha

    2009-02-01

    In the current research, diffuse optical imaging (DOI) is used for the first time towards studies related to sociocommunication impairments, which is a characteristic feature of autism. DOI studies were performed on normal adult volunteers to determine the differences in the brain activation (cognitive regions) in terms of the changes in the cerebral blood oxygenation levels in response to joint and non-joint attention based stimulus (i.e. socio-communicative paradigms shown as video clips). Functional connectivity models are employed to assess the extent of synchronization between the left and right pre-frontal regions of the brain in response to the above stimuli.

  7. Magneto-optic properties and optical parameter of thin MnCo films

    Directory of Open Access Journals (Sweden)

    E Attaran Kakhki

    2009-09-01

    Full Text Available Having precise hysterics loop of thin ferroelectric and ferromagnetic layers for optical switching and optical storages are important. A hysterieses loop can be achieved from a phenomenon call the magneto-optic effect. The magneto-optic effect is the rotation of a linear polarized electromagnetic wave propagated through a ferromagnetic medium. When light is transmitted through a layer of magnetic material the result is called the Faraday effects and in the reflection mode Kerr effect. In the present work we prepared a thin layer of MnxCo3-xO4 (0≤ x ≤ 1 and a binary form of MnO/Co3O4 by the spray pyrolysis method. The films have been characterized by a special set up of magneto-optic hysterics loop plotter containing a polarized He- Ne laser beam and a special electronic circuit. Faraday rotation were measured for these films by hysterics loop plotter and their optical properties were also obtained by spatial software designed for this purpose according to Swane Poel theoretical method. The measurements show that the samples at diluted Mn study has are ferromagnetic and the magneto-optic rotation show a good enhance respect to the single Co layers. Also, the study has shown that the MnCo oxide layer have two different energy gaps and by increasing of Mn this energy decreases and fall to 0.13 eV.

  8. Noninvasive optical monitoring multiple physiological parameters response to cytokine storm

    Science.gov (United States)

    Li, Zebin; Li, Ting

    2018-02-01

    Cancer and other disease originated by immune or genetic problems have become a main cause of death. Gene/cell therapy is a highlighted potential method for the treatment of these diseases. However, during the treatment, it always causes cytokine storm, which probably trigger acute respiratory distress syndrome and multiple organ failure. Here we developed a point-of-care device for noninvasive monitoring cytokine storm induced multiple physiological parameters simultaneously. Oxy-hemoglobin, deoxy-hemoglobin, water concentration and deep-tissue/tumor temperature variations were simultaneously measured by extended near infrared spectroscopy. Detection algorithms of symptoms such as shock, edema, deep-tissue fever and tissue fibrosis were developed and included. Based on these measurements, modeling of patient tolerance and cytokine storm intensity were carried out. This custom device was tested on patients experiencing cytokine storm in intensive care unit. The preliminary data indicated the potential of our device in popular and milestone gene/cell therapy, especially, chimeric antigen receptor T-cell immunotherapy (CAR-T).

  9. Ring current and auroral electrojets in connection with interplanetary medium parameters during magnetic storm

    Directory of Open Access Journals (Sweden)

    Y. I. Feldstein

    Full Text Available The relationship between the auroral electrojet indices (AE and the ring current magnetic field (DR was investigated by observations obtained during the magnetic storm on 1-3 April 1973. During the storm main phase the DR development is accompanied by a shift of the auroral electrojets toward the equator. As a result, the standard AE indices calculated on the basis of data from auroral observatories was substantially lower than the real values (AE'. To determine AE' during the course of a storm main phase data from subauroral magnetic observatories should be used. It is shown that the intensity of the indices (AE' which take into account the shift of the electrojets is increased substantially relative to the standard indices during the storm main phase. AE' values are closely correlated with geoeffective solar wind parameters. A high correlation was obtained between AE' and the energy flux into the ring current during the storm main phase. Analysis of magnetic field variations during intervals with intense southward IMF components demonstrates a decrease of the saturation effect of auroral electrojet currents if subauroral stations magnetic field variations are taken into account. This applies both to case studies and statistical data. The dynamics of the electrojets in connection with the development of the ring current and of magnetospheric substorms can be described by the presence (absence of saturation for minimum (maximum AE index values during a 1-h interval. The ring current magnetic field asymmetry (ASY was calculated as the difference between the maximum and minimum field values along a parallel of latitude at low latitudes. The ASY value is closely correlated with geoeffective solar wind parameters and simultaneously is a more sensitive indicator of IMF Bz variations than the symmetric ring current.

  10. Optical parameters of the tunable Bragg reflectors in squid.

    Science.gov (United States)

    Ghoshal, Amitabh; Demartini, Daniel G; Eck, Elizabeth; Morse, Daniel E

    2013-08-06

    Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryteuthis opalescens. This subcellular, single-stack microspectrophotometry allows for spectral normalization, permitting use of a transfer-matrix model of Bragg reflectance to calculate all the parameters of the Bragg stack-the refractive indices, dimensions and numbers of the lamellae and inter-lamellar spaces. Results of the fitting analyses show that eight or nine pairs of low- and high-index layers typically contribute to the observed reflectivity in live cells, whereas six or seven pairs of low- and high-index layers typically contribute to the reflectivity in chemically fixed cells. The reflectin-containing, high-index lamellae of live cells have a refractive index proportional to the peak reflectivity, with an average of 1.405 ± 0.012 and a maximum around 1.44, while the reflectin-containing lamellae in fixed tissue have a refractive index of 1.413 ± 0.015 suggesting a slight increase of refractive index in the process of fixation. As expected, incremental changes in refractive index contribute to the greatest incremental changes in reflectivity for those Bragg stacks with the most layers. The excursions in dimensions required to tune the measured reflected wavelength from 675 (red) to 425 nm (blue) are a decrease from ca 150 to 80 nm for the high-index lamellae and from ca 120 to 50 nm for the low-index inter-lamellar spaces. Fixation-induced dimensional changes also are quantified, leading us to suggest that further microspectrophotometric analyses of this iridocyte

  11. Reproducibility of Perfusion Parameters of Optic Disc and Macula in Rhesus Monkeys by Optical Coherence Tomography Angiography.

    Science.gov (United States)

    Li, Jing; Yang, Yi-Quan; Yang, Di-Ya; Liu, Xiang-Xiang; Sun, Yun-Xiao; Wei, Shi-Fei; Wang, Ning-Li

    2016-05-05

    Optical coherence tomography (OCT) angiography is a novel technique by which we can detect the local perfusion of fundus directly. The aim of this study was to evaluate the reproducibility of optic disc and macular flow perfusion parameters in rhesus monkeys using OCT angiography. Eighteen healthy monkeys (18 eyes) were subjected to optic disc and macula flow index measurements via a high-speed and high-resolution spectral-domain OCT XR Avanti with a split-spectrum amplitude de-correlation angiography algorithm. Right eye was imaged 3 times during the first examination and once during each of the two following examinations. The intra-visit and inter-visit intraclass correlation coefficients (ICCs) were both determined. The average flow indices of the four optic disc area layers were 0.171 ± 0.009 (optic nerve head), 0.015 ± 0.004 (vitreous), 0.052 ± 0.009 (radial peripapillary capillary), and 0.167 ± 0.011 (choroid). Average flow indices of the four macula area layers were 0.044 ± 0.011 (superficial retina), 0.036 ± 0.011 (deep retina), 0.016 ± 0.009 (outer retina), and 0.155 ± 0.013 (choroid). Intra-visit (ICC value: 0.821-0.954) and inter-visit (ICC value: 0.844-0.899) repeatability were both high. The study is about the reproducibility of optic disc and macular perfusion parameters as measured by OCT angiography in healthy rhesus monkeys. Flow index measurement reproducibility is high for both the optic disc and macula of normal monkey eyes. OCT angiography might be a useful technique to assess changes when examining monkeys with experimental ocular diseases.

  12. Time-domain scanning optical mammography: II. Optical properties and tissue parameters of 87 carcinomas

    International Nuclear Information System (INIS)

    Grosenick, Dirk; Wabnitz, Heidrun; Moesta, K Thomas; Mucke, Joerg; Schlag, Peter M; Rinneberg, Herbert

    2005-01-01

    Within a clinical trial on scanning time-domain optical mammography reported on in a companion publication (part I), craniocaudal and mediolateral projection optical mammograms were recorded from 154 patients, suspected of having breast cancer. Here we report on in vivo optical properties of the subset of 87 histologically validated carcinomas which were visible in optical mammograms recorded at two or three near-infrared wavelengths. Tumour absorption and reduced scattering coefficients were derived from distributions of times of flight of photons recorded at the tumour site employing the model of diffraction of photon density waves by a spherical inhomogeneity, located in an otherwise homogeneous tissue slab. Effective tumour radii, taken from pathology, and tumour location along the compression direction, deduced from off-axis optical scans of the tumour region, were included in the analysis as prior knowledge, if available. On average, tumour absorption coefficients exceeded those of surrounding healthy breast tissue by a factor of about 2.5 (670 nm), whereas tumour reduced scattering coefficients were larger by about 20% (670 nm). From absorption coefficients at 670 nm and 785 nm total haemoglobin concentration and blood oxygen saturation were deduced for tumours and surrounding healthy breast tissue. Apart from a few outliers total haemoglobin concentration was observed to be systematically larger in tumours compared to healthy breast tissue. In contrast, blood oxygen saturation was found to be a poor discriminator for tumours and healthy breast tissue; both median values of blood oxygen saturation are the same within their statistical uncertainties. However, the ratio of total haemoglobin concentration over blood oxygen saturation further improves discrimination between tumours and healthy breast tissue. For 29 tumours detected in optical mammograms recorded at three wavelengths (670 nm, 785 nm, 843 nm or 884 nm), scatter power was derived from transport

  13. Optical absorption in planar graphene superlattice: The role of structural parameters

    Science.gov (United States)

    Azadi, L.; Shojaei, S.

    2018-04-01

    We theoretically studied the optically driven interband transitions in a planar graphene superlattices (PGSL) formed by patterning graphene sheet on laterally hetrostructured substrate as Sio2/hBN. A tunable optical transitions between minibands is observed based on engineering structural parameters. We derive analytically expression for optical absorption from two-band model. Considerable optical absorption is obtained for different ratios between widths of heterostructured substrate and is explained analytically from the view point of wavefunction engineering and miniband dispersion, in details. The role of different statuses of polarization as circular and linear are considered. Our study paves a way toward the control of optical properties of PGSLs to be implemented in optoelectronics devices.

  14. Mode analysis and structure parameter optimization of a novel SiGe-OI rib optical waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Feng Song; Gao Yong; Yang Yuan [Department of Electronic Engineering, Xi' an University of Technology, Xi' an 710048 (China); Feng Yuchun, E-mail: vonfs@yahoo.com.c [Key Laboratories of Optoelectronic Devices and Systems, Shenzhen University, Shenzhen 518060 (China)

    2009-08-15

    The mode of a novel SiGe-OI optical waveguide is analyzed, and its single-mode conditions are derived. The Ge content and structure parameters of SiGe-OI optical waveguides are respectively optimized. Under an operation wavelength of 1300 nm, the structures of SiGe-OI rib optical waveguides are built and analyzed with Optiwave software, and the optical field and transmission losses of the SiGe-OI rib optical waveguides are analyzed. The optimization results show that when the structure parameters H, h, W are respectively 500 nm, 250 nm, 500 nm and the Ge content is 5%, the total power loss of SiGe-OI rib waveguides is 0.3683 dB/cm considering the loss of radiation outside the waveguides and materials, which is less than the traditional value of 0.5 dB/cm. The analytical technique for SiGe-OI optical waveguides and structure parameters computed by this paper are proved to be accurate and computationally efficient compared with the beam propagation method (BPM) and the experimental results. (semiconductor devices)

  15. Effect of the channel electron multiplier connection diagram on its parameters

    International Nuclear Information System (INIS)

    Ajnbund, M.R.

    1976-01-01

    Basic alternatives of connection of a channel electron multiplier are described. A dependence of a gain factor and amplitude resolution of the channel electron multiplier upon its connection diagram is studied. The studies have shown that the maximum gain factor is typical of an open-output circuit where the signal is recorded from the anode of the channel electron multiplier at a potential with respect to the channel outlet. The highest amplitude resolution is inherent in a separate-anode circuit where the loading resistance is connected directly to the channel outlet

  16. Impact of Various Parameters on the Performance of Inter-aircraft Optical Wireless Communication Link

    Science.gov (United States)

    Singh, Mehtab

    2017-12-01

    Optical wireless communication (OWC) systems also known as Free space optics (FSO) are capable of providing high channel bandwidth, high data transmission rates, low power consumption, and high security. OWC links are being considered in different applications such as inter-satellite links, terrestrial links, and inter-aircraft communication links. This paper investigates the impact of different system parameters such as transmission power level, operating wavelength, transmitter pointing error angle, bit transmission rate, atmospheric attenuation, antenna aperture diameter, geometric losses, the responsivity of the photodetector, and link range on the performance of inter-aircraft optical wireless communication link.

  17. Fine-Tuning ADAS Algorithm Parameters for Optimizing Traffic Safety and Mobility in Connected Vehicle Environment

    Science.gov (United States)

    With the development of Connected Vehicle Technology that facilitates wireless communication among vehicles and road-side infrastructure, the Advanced Driver Assistance Systems (ADAS) can be adopted as an effective tool for accelerating traffic safety and mobility optimization at...

  18. Parameter design and experimental study of a bifunctional isolator for optical payload protection and stabilization

    Science.gov (United States)

    Wang, Guang-yuan; Guan, Xin; Cao, Dong-jing; Tang, Shao-fan; Chen, Xiang; Liang, Lu; Zheng, Gang-tie

    2017-11-01

    With the raise of resolution, optical payloads are becoming increasingly sensitive to satellite jitter. An approach where the entire spacecraft is pointed with great accuracy requires sophisticated and expensive bus design. In an effort to lower the overall cost of space missions that require highly stable line-of-sight pointing, a method of separating the bus and the payload with low frequency isolators is proposed. This isolation system can block the transmission of disturbance and allow relatively large bus motion. However, if the isolator is linear then there is a trade-off between isolation and static deflection as the launch and the on-orbit stage have difference requirements on the isolation frequency. Otherwise, an extra locking system should be appended to protect the payload before getting into orbit, as the STABLE isolation system[1] and the MIM isolation system[2] did. To overcome this limitation, an alternative approach is to design a nonlinear isolator with high-static stiffness during launch and low dynamic stiffness on orbit. Several specially designed nonlinear isolators have achieved low dynamic stiffness with large static load capacity. Virgin[3] considered a structure made from a highly deformed elastic element to achieve a softening spring. Platus[4] exploited the buckling of beams under axial load in a specific configuration to achieve a negative stiffness in combination with a positive stiffness, and hence low-dynamic stiffness. Others have achieved the same by connecting linear springs with positive stiffness in parallel with elements of negative stiffness[5] [7]. In the present study, a bifunctional isolator has been developed for optical payloads. The isolator have good performance both during launch and on orbit because of its specially designed nonlinear stiffness and damping. The isolator works in a linear part with low stiffness and small damping ratio under the micro-vibration and microgravity on orbit. The transmissibility

  19. Integrated monitoring of multi-domain backbone connections Operational experience in the LHC optical private network

    CERN Document Server

    Marcu, Patricia; Fritz, Wolfgang; Yampolskiy, Mark; Hommel, Wolfgang

    2011-01-01

    Novel large scale research projects often require cooperation between various different project partners that are spread among the entire world. They do not only need huge computing resources, but also a reliable network to operate on. The Large Hadron Collider (LHC) at CERN is a representative example for such a project. Its experiments result in a vast amount of data, which is interesting for researchers around the world. For transporting the data from CERN to 11 data processing and storage sites, an optical private network (OPN) has been constructed. As the experiment data is highly valuable, LHC defines very high requirements to the underlying network infrastructure. In order to fulfil those requirements, the connections have to be managed and monitored permanently. In this paper, we present the integrated monitoring solution developed for the LHCOPN. We first outline the requirements and show how they are met on the single network layers. After that, we describe, how those single measurements can be comb...

  20. Two-step frequency conversion for connecting distant quantum memories by transmission through an optical fiber

    Science.gov (United States)

    Tamura, Shuhei; Ikeda, Kohei; Okamura, Kotaro; Yoshii, Kazumichi; Hong, Feng-Lei; Horikiri, Tomoyuki; Kosaka, Hideo

    2018-06-01

    Long-distance quantum communication requires entanglement between distant quantum memories. For this purpose, photon transmission is necessary to connect the distant memories. Here, for the first time, we develop a two-step frequency conversion process (from a visible wavelength to a telecommunication wavelength and back) involving the use of independent two-frequency conversion media where the target quantum memories are nitrogen-vacancy centers in diamonds (with an emission/absorption wavelength of 637.2 nm), and experimentally characterize the performance of this process acting on light from an attenuated CW laser. A total conversion efficiency of approximately 7% is achieved. The noise generated in the frequency conversion processes is measured, and the signal-to-noise ratio is estimated for a single photon signal emitted by a nitrogen-vacancy (NV) center. The developed frequency conversion system has future applications via transmission through a long optical fiber channel at a telecommunication wavelength for a quantum repeater network.

  1. The Connective Tissue Components of Optic Nerve Head Cupping in Monkey Experimental Glaucoma Part 1: Global Change

    Science.gov (United States)

    Yang, Hongli; Ren, Ruojin; Lockwood, Howard; Williams, Galen; Libertiaux, Vincent; Downs, Crawford; Gardiner, Stuart K.; Burgoyne, Claude F.

    2015-01-01

    Purpose To characterize optic nerve head (ONH) connective tissue change within 21 monkey experimental glaucoma (EG) eyes, so as to identify its principal components. Methods Animals were imaged three to five times at baseline then every 2 weeks following chronic unilateral IOP elevation, and euthanized early through end-stage confocal scanning laser tomographic change. Optic nerve heads were serial-sectioned, three-dimensionally (3D) reconstructed, delineated, and quantified. Overall EG versus control eye differences were assessed by general estimating equations (GEE). Significant, animal-specific, EG eye change was required to exceed the maximum physiologic intereye differences in six healthy animals. Results Overall EG eye change was significant (P connective tissue components of ONH “cupping” in monkey EG which serve as targets for longitudinally staging and phenotyping ONH connective tissue alteration within all forms of monkey and human optic neuropathy. PMID:26641545

  2. Sensitivity of corneal biomechanical and optical behavior to material parameters using design of experiments method.

    Science.gov (United States)

    Xu, Mengchen; Lerner, Amy L; Funkenbusch, Paul D; Richhariya, Ashutosh; Yoon, Geunyoung

    2018-02-01

    The optical performance of the human cornea under intraocular pressure (IOP) is the result of complex material properties and their interactions. The measurement of the numerous material parameters that define this material behavior may be key in the refinement of patient-specific models. The goal of this study was to investigate the relative contribution of these parameters to the biomechanical and optical responses of human cornea predicted by a widely accepted anisotropic hyperelastic finite element model, with regional variations in the alignment of fibers. Design of experiments methods were used to quantify the relative importance of material properties including matrix stiffness, fiber stiffness, fiber nonlinearity and fiber dispersion under physiological IOP. Our sensitivity results showed that corneal apical displacement was influenced nearly evenly by matrix stiffness, fiber stiffness and nonlinearity. However, the variations in corneal optical aberrations (refractive power and spherical aberration) were primarily dependent on the value of the matrix stiffness. The optical aberrations predicted by variations in this material parameter were sufficiently large to predict clinically important changes in retinal image quality. Therefore, well-characterized individual variations in matrix stiffness could be critical in cornea modeling in order to reliably predict optical behavior under different IOPs or after corneal surgery.

  3. Optimization of Thixoforging Parameters for C70S6 Steel Connecting Rods

    Science.gov (United States)

    Özkara, İsa Metin; Baydoğan, Murat

    2016-11-01

    A microalloyed steel, C70S6, with a solidification interval of 1390-1479 °C, was thixoforged in the semisolid state in a closed die at temperatures in the range 1400-1475 °C to form a 1/7 scaled-down model of a passenger vehicle connecting rod. Die design and an optimized thixoforging temperature eliminated the excessive flash and other problems during forging. Tension test samples from connecting rods thixoforged at the optimum temperature of 1440 °C exhibited nearly the same hardness, yield strength, and ultimate tensile strength as conventional hot forged samples but ductility decreased by about 45% due to grain boundary ferrite network formed during cooling from the thixoforging temperature. Thus, C70S6-grade steel can be thixoforged at 1440 °C to form flash-free connecting rods. This conclusion was also validated using FEA analysis.

  4. Dielectric and electro-optical parameters of two ferroelectric liquid crystals: a comparative study

    International Nuclear Information System (INIS)

    Kumar Misra, Abhishek; Kumar Srivastava, Abhishek; Shukla, J P; Manohar, Rajiv

    2008-01-01

    Dielectric relaxation and an electro-optical study of two ferroelectric liquid crystals having different spontaneous polarizations (Felix 16/100 and Felix 17/000) showing SmC* and SmA phases have been performed in the temperature range 30-80 compfn C. The experimental data have been used to determine different relaxation parameters, viz. distribution parameter, relaxation frequency, dielectric strength and rotational viscosity. The Goldstone mode of dielectric permittivity has been well observed for both the samples under investigation. The activation energy of both the samples has also been determined by the best theoretical fitting of the Arrhenius plot. We have also evaluated the optical response time and anchoring energy coefficients from electro-optical measurement techniques for these samples.

  5. Control of operating parameters of laser ceilometers with the application of fiber optic delay line imitation

    Science.gov (United States)

    Kim, A. A.; Klochkov, D. V.; Konyaev, M. A.; Mihaylenko, A. S.

    2017-11-01

    The article considers the problem of control and verification of the laser ceilometers basic performance parameters and describes an alternative method based on the use of multi-length fiber optic delay line, simulating atmospheric track. The results of the described experiment demonstrate the great potential of this method for inspection and verification procedures of laser ceilometers.

  6. Statistical classifiers on multifractal parameters for optical diagnosis of cervical cancer

    Science.gov (United States)

    Mukhopadhyay, Sabyasachi; Pratiher, Sawon; Kumar, Rajeev; Krishnamoorthy, Vigneshram; Pradhan, Asima; Ghosh, Nirmalya; Panigrahi, Prasanta K.

    2017-06-01

    An augmented set of multifractal parameters with physical interpretations have been proposed to quantify the varying distribution and shape of the multifractal spectrum. The statistical classifier with accuracy of 84.17% validates the adequacy of multi-feature MFDFA characterization of elastic scattering spectroscopy for optical diagnosis of cancer.

  7. Impact of geometrical parameters on the optical properties of negative curvature hollow-core fibers

    International Nuclear Information System (INIS)

    Alagashev, G K; Pryamikov, A D; Kosolapov, A F; Kolyadin, A N; Lukovkin, A Yu; Biriukov, A S

    2015-01-01

    We analyze the impact of geometrical parameters on such important optical characteristics of negative curvature hollow-core fibers (NCHCFs) as waveguide dispersion, waveguide losses and the structure of transmission bands. We consider both theoretically and experimentally the resonance effects and formation of band edges under bending in NCHCFs. (paper)

  8. Pose measurement method with six parameters for microassembly based on an optical micrometer

    Science.gov (United States)

    Ye, Xin; Wang, Qiang; Zhang, Zhi-jing; Sun, Yuan; Zhang, Xiao-feng

    2009-07-01

    This paper presents a new pose measurement method of microminiature parts that is capable of transforming one dimension (1D) contour size obtained by optical micrometer to three dimension (3D) data with six parameters for microassembly. Pose measurement is one of the most important processes for microminiature parts' alignment and insertion in microassembly. During the past few years, researchers have developed their microassembly systems focusing on visual identification to obtain two or three dimension data with no more than three parameters. Scanning electronic microscope (SEM), optical microscope, and stereomicroscope are applied in their systems. However, as structures of microminiature parts become increasingly complex, six parameters to represent their position and orientation are specifically needed. Firstly, The pose measurement model is established based on the introduction of measuring objects and measuring principle of optical micrometer. The measuring objects are microminiature parts with complex 3D structure. Two groups of two dimension (2D) data are gathered at two different measurement positions. Then part pose with 6 parameters is calculated, including 3 position parameters of feature point of the part and 3 orientation parameters of the part axis. Secondly, pose measurement process for a small shaft, vertical orientation determination, and position parameters obtaining are presented. 2D data is gathered by scanning the generatrix of the part, and valid data is extracted and saved in arrays. A vertical orientation criterion is proposed to determine whether the part is parallel to the Z-axis of the coordinate. If not, 2D data will be fixed into a linear equation using least square algorithm. Then orientation parameters are calculated. Center of Part End (CPE) is selected as feature point of the part, and its position parameters are extracted form two group of 2D data. Finally, a fast pose measurement device is developed and representative

  9. Artificial neural networks based estimation of optical parameters by diffuse reflectance imaging under in vitro conditions

    Directory of Open Access Journals (Sweden)

    Mahmut Ozan Gökkan

    2017-01-01

    Full Text Available Optical parameters (properties of tissue-mimicking phantoms are determined through noninvasive optical imaging. Objective of this study is to decompose obtained diffuse reflectance into these optical properties such as absorption and scattering coefficients. To do so, transmission spectroscopy is firstly used to measure the coefficients via an experimental setup. Next, the optical properties of each characterized phantom are input for Monte Carlo (MC simulations to get diffuse reflectance. Also, a surface image for each single phantom with its known optical properties is obliquely captured due to reflectance-based geometrical setup using CMOS camera that is positioned at 5∘ angle to the phantoms. For the illumination of light, a laser light source at 633nm wavelength is preferred, because optical properties of different components in a biological tissue on that wavelength are nonoverlapped. During in vitro measurements, we prepared 30 different mixture samples adding clinoleic intravenous lipid emulsion (CILE and evans blue (EB dye into a distilled water. Finally, all obtained diffuse reflectance values are used to estimate the optical coefficients by artificial neural networks (ANNs in inverse modeling. For a biological tissue it is found that the simulated and measured values in our results are in good agreement.

  10. The effect of laser ablation parameters on optical limiting properties of silver nanoparticles

    Science.gov (United States)

    Gursoy, Irmak; Yaglioglu, Halime Gul

    2017-09-01

    This paper presents the effect of laser ablation parameters on optical limiting properties of silver nanoparticles. The current applications of lasers such as range finding, guidance, detection, illumination and designation have increased the potential of damaging optical imaging systems or eyes temporary or permanently. The applications of lasers introduce risks for sensors or eyes, when laser power is higher than damage threshold of the detection system. There are some ways to protect these systems such as neutral density (nd) filters, shutters, etc. However, these limiters reduce the total amount of light that gets into the system. Also, response time of these limiters may not be fast enough to prevent damage and cause precipitation in performance due to deprivation of transmission or contrast. Therefore, optical limiting filters are needed that is transparent for low laser intensities and limit or block the high laser intensities. Metal nanoparticles are good candidates for such optical limiting filters for ns pulsed lasers or CW lasers due to their high damage thresholds. In this study we investigated the optical limiting performances of silver nanoparticles produced by laser ablation technique. A high purity silver target immersed in pure water was ablated with a Nd:YAG nanosecond laser at 532 nm. The effect of altering laser power and ablation time on laser ablation efficiency of nanoparticles was investigated experimentally and optimum values were specified. Open aperture Zscan experiment was used to investigate the effect of laser ablation parameters on the optical limiting performances of silver nanoparticles in pure water. It was found that longer ablation time decreases the optical limiting threshold. These results are useful for silver nanoparticles solutions to obtain high performance optical limiters.

  11. Contrasting brain patterns of writing-related DTI parameters, fMRI connectivity, and DTI–fMRI connectivity correlations in children with and without dysgraphia or dyslexia

    Science.gov (United States)

    Richards, T.L.; Grabowski, T.J.; Boord, P.; Yagle, K.; Askren, M.; Mestre, Z.; Robinson, P.; Welker, O.; Gulliford, D.; Nagy, W.; Berninger, V.

    2015-01-01

    Based on comprehensive testing and educational history, children in grades 4–9 (on average 12 years) were diagnosed with dysgraphia (persisting handwriting impairment) or dyslexia (persisting word spelling/reading impairment) or as typical writers and readers (controls). The dysgraphia group (n = 14) and dyslexia group (n = 17) were each compared to the control group (n = 9) and to each other in separate analyses. Four brain region seed points (left occipital temporal gyrus, supramarginal gyrus, precuneus, and inferior frontal gyrus) were used in these analyses which were shown in a metaanalysis to be related to written word production on four indicators of white matter integrity and fMRI functional connectivity for four tasks (self-guided mind wandering during resting state, writing letter that follows a visually displayed letter in alphabet, writing missing letter to create a correctly spelled real word, and planning for composing after scanning on topic specified by researcher). For those DTI indicators on which the dysgraphic group or dyslexic group differed from the control group (fractional anisotropy, relative anisotropy, axial diffusivity but not radial diffusivity), correlations were computed between the DTI parameter and fMRI functional connectivity for the two writing tasks (alphabet and spelling) by seed points. Analyses, controlled for multiple comparisons, showed that (a) the control group exhibited more white matter integrity than either the dysgraphic or dyslexic group; (b) the dysgraphic and dyslexic groups showed more functional connectivity than the control group but differed in patterns of functional connectivity for task and seed point; and (c) the dysgraphic and dyslexic groups showed different patterns of significant DTI–fMRI connectivity correlations for specific seed points and written language tasks. Thus, dysgraphia and dyslexia differ in white matter integrity, fMRI functional connectivity, and white matter–gray matter

  12. Contrasting brain patterns of writing-related DTI parameters, fMRI connectivity, and DTI–fMRI connectivity correlations in children with and without dysgraphia or dyslexia

    Directory of Open Access Journals (Sweden)

    T.L. Richards

    2015-01-01

    Full Text Available Based on comprehensive testing and educational history, children in grades 4–9 (on average 12 years were diagnosed with dysgraphia (persisting handwriting impairment or dyslexia (persisting word spelling/reading impairment or as typical writers and readers (controls. The dysgraphia group (n = 14 and dyslexia group (n = 17 were each compared to the control group (n = 9 and to each other in separate analyses. Four brain region seed points (left occipital temporal gyrus, supramarginal gyrus, precuneus, and inferior frontal gyrus were used in these analyses which were shown in a metaanalysis to be related to written word production on four indicators of white matter integrity and fMRI functional connectivity for four tasks (self-guided mind wandering during resting state, writing letter that follows a visually displayed letter in alphabet, writing missing letter to create a correctly spelled real word, and planning for composing after scanning on topic specified by researcher. For those DTI indicators on which the dysgraphic group or dyslexic group differed from the control group (fractional anisotropy, relative anisotropy, axial diffusivity but not radial diffusivity, correlations were computed between the DTI parameter and fMRI functional connectivity for the two writing tasks (alphabet and spelling by seed points. Analyses, controlled for multiple comparisons, showed that (a the control group exhibited more white matter integrity than either the dysgraphic or dyslexic group; (b the dysgraphic and dyslexic groups showed more functional connectivity than the control group but differed in patterns of functional connectivity for task and seed point; and (c the dysgraphic and dyslexic groups showed different patterns of significant DTI–fMRI connectivity correlations for specific seed points and written language tasks. Thus, dysgraphia and dyslexia differ in white matter integrity, fMRI functional connectivity, and white matter–gray matter

  13. Generator Dynamic Model Validation and Parameter Calibration Using Phasor Measurements at the Point of Connection

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhenyu; Du, Pengwei; Kosterev, Dmitry; Yang, Steve

    2013-05-01

    Disturbance data recorded by phasor measurement units (PMU) offers opportunities to improve the integrity of dynamic models. However, manually tuning parameters through play-back events demands significant efforts and engineering experiences. In this paper, a calibration method using the extended Kalman filter (EKF) technique is proposed. The formulation of EKF with parameter calibration is discussed. Case studies are presented to demonstrate its validity. The proposed calibration method is cost-effective, complementary to traditional equipment testing for improving dynamic model quality.

  14. The quantum dynamics of two qubits inside two distant microcavities connected via a single-mode optical fiber

    International Nuclear Information System (INIS)

    Nguyen, Van Hieu; Nguyen, Bich Ha; Duong, Hai Trieu

    2010-01-01

    For application to studying the transmission of quantum information, also called quantum communication, between two identical qubits placed inside two identical single-mode microcavities connected via a single-mode optical fiber, the time evolution of this system is investigated. In the Markovian approximation, the von Neumann equation for its reduced density matrix contains a completely positive linear operator called the Liouvillian operator describing the decoherence of this system due to its interaction with the environment. By using the Linblad formula for the Liouvillian operator, a system of rate equations can be derived. In the special case of resonance between the energy difference of two states in each qubit and the energy of the fiber mode, the rate equations for the system excited up to the first level are solved in first order approximation with respect to the decoherence constants. It is shown that when there is no decoherence, the perfect quantum state transmission between two qubits can take place if the physical parameters of the system satisfy definite conditions. A possible extension to studying the system excited to high energy states is also discussed

  15. SU-E-J-161: Inverse Problems for Optical Parameters in Laser Induced Thermal Therapy

    International Nuclear Information System (INIS)

    Fahrenholtz, SJ; Stafford, RJ; Fuentes, DT

    2014-01-01

    Purpose: Magnetic resonance-guided laser-induced thermal therapy (MRgLITT) is investigated as a neurosurgical intervention for oncological applications throughout the body by active post market studies. Real-time MR temperature imaging is used to monitor ablative thermal delivery in the clinic. Additionally, brain MRgLITT could improve through effective planning for laser fiber's placement. Mathematical bioheat models have been extensively investigated but require reliable patient specific physical parameter data, e.g. optical parameters. This abstract applies an inverse problem algorithm to characterize optical parameter data obtained from previous MRgLITT interventions. Methods: The implemented inverse problem has three primary components: a parameter-space search algorithm, a physics model, and training data. First, the parameter-space search algorithm uses a gradient-based quasi-Newton method to optimize the effective optical attenuation coefficient, μ-eff. A parameter reduction reduces the amount of optical parameter-space the algorithm must search. Second, the physics model is a simplified bioheat model for homogeneous tissue where closed-form Green's functions represent the exact solution. Third, the training data was temperature imaging data from 23 MRgLITT oncological brain ablations (980 nm wavelength) from seven different patients. Results: To three significant figures, the descriptive statistics for μ-eff were 1470 m −1 mean, 1360 m −1 median, 369 m −1 standard deviation, 933 m −1 minimum and 2260 m −1 maximum. The standard deviation normalized by the mean was 25.0%. The inverse problem took <30 minutes to optimize all 23 datasets. Conclusion: As expected, the inferred average is biased by underlying physics model. However, the standard deviation normalized by the mean is smaller than literature values and indicates an increased precision in the characterization of the optical parameters needed to plan MRgLITT procedures. This investigation

  16. Comparison of three optical models and analysis of geometric parameters for parabolic trough solar collectors

    International Nuclear Information System (INIS)

    Liang, Hongbo; You, Shijun; Zhang, Huan

    2016-01-01

    A PTC (parabolic trough solar collector) focuses direct solar radiation reflected by the reflector onto a receiver located on its focal line. The solar flux distribution on the absorber is non-uniform generally, thus it needs to carry out optical simulation to analyze the concentrated flux density and optical performance. In this paper, three different optical models based on ray tracing for a PTC were proposed and compared in detail. They were proved to be feasible and reliable in comparison with other literature. Model 1 was based on MCM (Monte Carlo Method). Model 2 initialized photon distribution with FVM (Finite Volume Method), and calculated reflection, transmission, and absorption by means of MCM. Model 3 utilized FVM to determine ray positions initially, while it changed the photon energy by multiplying reflectivity, transmissivity and absorptivity. The runtime and computation effort of Model 3 were approximately 40% and 60% of that of Model 1 in the present work. Moreover, the simulation result of Model 3 was not affected by the algorithm for generating random numbers, however, it needed to take account of suitable grid configurations for different sections of the system. Additionally, effects of varying the geometric parameters for a PTC on optical efficiency were estimated. Effect of offsetting the absorber in width direction of aperture was greater than that in its normal direction at the same offset distance, which was more obvious with offset distance increasing. Furthermore, absorber offset at the opposite direction of tracking error was beneficial for improving optical performance. The larger rim angle (≤90°) was, the less sensitive optical efficiency was to tracking error for the same aperture width of a PTC. In contrast, a larger aperture width was more sensitive to tracking error for a certain rim angle. - Highlights: • Three different optical models for parabolic trough solar collectors were derived. • Their running time, computation

  17. Exploiting Auto-Collimation for Real-Time Onboard Monitoring of Space Optical Camera Geometric Parameters

    Science.gov (United States)

    Liu, W.; Wang, H.; Liu, D.; Miu, Y.

    2018-05-01

    Precise geometric parameters are essential to ensure the positioning accuracy for space optical cameras. However, state-of-the-art onorbit calibration method inevitably suffers from long update cycle and poor timeliness performance. To this end, in this paper we exploit the optical auto-collimation principle and propose a real-time onboard calibration scheme for monitoring key geometric parameters. Specifically, in the proposed scheme, auto-collimation devices are first designed by installing collimated light sources, area-array CCDs, and prisms inside the satellite payload system. Through utilizing those devices, the changes in the geometric parameters are elegantly converted into changes in the spot image positions. The variation of geometric parameters can be derived via extracting and processing the spot images. An experimental platform is then set up to verify the feasibility and analyze the precision index of the proposed scheme. The experiment results demonstrate that it is feasible to apply the optical auto-collimation principle for real-time onboard monitoring.

  18. Fourier transform infrared imaging and infrared fiber optic probe spectroscopy identify collagen type in connective tissues.

    Directory of Open Access Journals (Sweden)

    Arash Hanifi

    connective tissues, using both imaging and fiber optic methodology. This has great potential for clinical in situ applications for monitoring tissue repair.

  19. Effect of the geometrical parameters of an optical integrator on the unformity of the radiation flux distribution

    International Nuclear Information System (INIS)

    Vishnyakova, T.P.; Klychev, Sh.I.

    1992-01-01

    The use of optical mixers in the optical irradiators of simulators of direct and concentrated solar radiation has been proposed. In this paper, the parameters of an optical mixer are calculated geometrically, and the effect of the parameters of the optical mixer on the unformity of the irradiance distribution η of the radiation flux on the detector is investigated. These investigations show that the light distribution from an optical mixer is close to the characteristics of an ideal uniform emitter within the region from 0 to the limit of α. 5 refs., 4 figs

  20. Comb-like optical transmission spectrum resulting from a four-cornered two-waveguide-connected network

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiangbo, E-mail: xbyang@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006 (China); Song, Huanhuan [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Liu, Timon Chengyi [School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006 (China)

    2013-12-06

    In this Letter a four-cornered two-waveguide-connected network (FCTWCN) is proposed to generate comb-like optical transmission spectrum, where nearest-neighbor nodes are connected by two segments of one-dimensional waveguides. We investigate the band structure and transmission spectrum of electromagnetic waves propagating through FCTWCNs and find that the transmission through a FCTWCN exhibits periodic comb-like characteristic and the range, number and width of continuous equidistant frequency bands can be controlled by adjusting the lengths of the two types of segments. The comb-like frequency bands may be useful for the designing of optical switches, optical narrowband filters, high capacity telecommunications, and multichannel filters, etc.

  1. A new procedure for estimating the cell temperature of a high concentrator photovoltaic grid connected system based on atmospheric parameters

    International Nuclear Information System (INIS)

    Fernández, Eduardo F.; Almonacid, Florencia

    2015-01-01

    Highlights: • Concentrating grid-connected systems are working at maximum power point. • The operating cell temperature is inherently lower than at open circuit. • Two novel methods for estimating the cell temperature are proposed. • Both predict the operating cell temperature from atmospheric parameters. • Experimental results show that both methods perform effectively. - Abstract: The working cell temperature of high concentrator photovoltaic systems is a crucial parameter when analysing their performance and reliability. At the same time, due to the special features of this technology, the direct measurement of the cell temperature is very complex and is usually obtained by using different indirect methods. High concentrator photovoltaic modules in a system are operating at maximum power since they are connected to an inverter. So that, their cell temperature is lower than the cell temperature of a module at open-circuit voltage since an important part of the light power density is converted into electricity. In this paper, a procedure for indirectly estimating the cell temperature of a high concentrator photovoltaic system from atmospheric parameters is addressed. Therefore, this new procedure has the advantage that is valid for estimating the cell temperature of a system at any location of interest if the atmospheric parameters are available. To achieve this goal, two different methods are proposed: one based on simple mathematical relationships and another based on artificial intelligent techniques. Results show that both methods predicts the cell temperature of a module connected to an inverter with a low margin of error with a normalised root mean square error lower or equal than 3.3%, an absolute root mean square error lower or equal than 2 °C, a mean absolute error lower or equal then 1.5 °C, and a mean bias error and a mean relative error almost equal to 0%

  2. Optical, electrical and the related parameters of amorphous Ge-Bi-Se thin films

    International Nuclear Information System (INIS)

    El-Korashy, A.; El-Kabany, N.; El-Zahed, H.

    2005-01-01

    The related optical and electrical parameters of amorphous Ge-Bi-Se thin films were studied. The dependence of optical and electrical properties on the Bi content was observed in most compositions. At Bi >10at% the behavior show a switch from p to n type conduction mechanism. The correlation between the optical band gap E g and the average heats of atomization H s were observed. The results indicated that both the number of topological constant N con and the radial and angular N α , N β valence force constants exhibit the same trend with increasing Bi content. On the other hand, the mean bond energy increases with increasing Bi content to x=15at%. It may be concluded that is a function of the mean coordination number N co , the type of bonds, the degree of cross-linking and the band energy forming the network

  3. Synergistic estimation of surface parameters from jointly using optical and microwave observations in EOLDAS

    Science.gov (United States)

    Timmermans, Joris; Gomez-Dans, Jose; Lewis, Philip; Loew, Alexander; Schlenz, Florian

    2017-04-01

    The large amount of remote sensing data nowadays available provides a huge potential for monitoring crop development, drought conditions and water efficiency. This potential however not been realized yet because algorithms for land surface parameter retrieval mostly use data from only a single sensor. Consequently products that combine different low-level observations from different sensors are hard to find. The lack of synergistic retrieval is caused because it is easier to focus on single sensor types/footprints and temporal observation times, than to find a way to compensate for differences. Different sensor types (microwave/optical) require different radiative transfer (RT) models and also require consistency between the models to have any impact on the retrieval of soil moisture by a microwave instrument. Varying spatial footprints require first proper collocation of the data before one can scale between different resolutions. Considering these problems, merging optical and microwave observations have not been performed yet. The goal of this research was to investigate the potential of integrating optical and microwave RT models within the Earth Observation Land Data Assimilation System (EOLDAS) synergistically to derive biophysical parameters. This system uses a Bayesian data assimilation approach together with observation operators such as the PROSAIL model to estimate land surface parameters. For the purpose of enabling the system to integrate passive microwave radiation (from an ELBARRA II passive microwave radiometer), the Community Microwave Emission Model (CMEM) RT-model, was integrated within the EOLDAS system. In order to quantify the potential, a variety of land surface parameters was chosen to be retrieved from the system, in particular variables that a) impact only optical RT (such as leaf water content and leaf dry matter), b) only impact the microwave RT (such as soil moisture and soil temperature), and c) Leaf Area Index (LAI) that impacts both

  4. Calculation of the Huang-Rhys parameter in spherical quantum dots: the optical deformation potential effect

    International Nuclear Information System (INIS)

    Hamma, M; Miranda, R P; Vasilevskiy, M I; Zorkani, I

    2007-01-01

    An accurate calculation of the exciton-phonon interaction matrix elements and Huang-Rhys parameter for nearly spherical nanocrystals (NCs) of polar semiconductor materials is presented. The theoretical approach is based on a continuum lattice dynamics model and the effective mass approximation for electronic states in the NCs. A strong confinement regime is considered for both excitons and optical phonons, taking into account both the Froehlich-type and optical deformation potential (ODP) mechanisms of the exciton-phonon interaction. The effects of exchange electron-hole interaction and possible hexagonal crystal structure of the underlying material are also taken into account. The theory is applied to CdSe and InP quantum dots. It is shown that the ODP mechanism, almost unimportant for CdSe, dominates the exciton-phonon coupling in small InP dots. The effect of the non-diagonal interaction, not included in the Huang-Rhys parameter, is briefly discussed

  5. Correcting Effect of Therapeutic Doses of Optical Radiation on Hematological Parameters of Blood Irradiated In Vivo

    Science.gov (United States)

    Zalesskaya, G. A.; Laskina, O. V.

    2017-07-01

    We studied the effect of therapeutic doses of optical radiation on the hematological parameters of blood irradiated in vivo: hemoglobin concentration, hematocrit, and the number of erythrocytes in the peripheral blood of patients during courses of extracorporeal, overvein, and intravenous blood irradiation and after treatment. The reversible changes during the procedures were found to differ from the changes obtained after treatment completion. At the end of the treatment course, the hematological parameters had changed in different directions and became higher, the same, or lower than the initial parameters depending on the initial parameters and photoinduced changes in blood oxygenation. A compensatory effect was found for photohemotherapy on oxygen-dependent processes altering the oxygen inflow into cells as well as the generation of active oxygen species and their inhibition by antioxidant systems.

  6. Characterization of PDMS samples with variation of its synthesis parameters for tunable optics applications

    Science.gov (United States)

    Marquez-Garcia, Josimar; Cruz-Félix, Angel S.; Santiago-Alvarado, Agustin; González-García, Jorge

    2017-09-01

    Nowadays the elastomer known as polydimethylsiloxane (PDMS, Sylgard 184), due to its physical properties, low cost and easy handle, have become a frequently used material for the elaboration of optical components such as: variable focal length liquid lenses, optical waveguides, solid elastic lenses, etc. In recent years, we have been working in the characterization of this material for applications in visual sciences; in this work, we describe the elaboration of PDMSmade samples, also, we present physical and optical properties of the samples by varying its synthesis parameters such as base: curing agent ratio, and both, curing time and temperature. In the case of mechanical properties, tensile and compression tests were carried out through a universal testing machine to obtain the respective stress-strain curves, and to obtain information regarding its optical properties, UV-vis spectroscopy is applied to the samples to obtain transmittance and absorbance curves. Index of refraction variation was obtained through an Abbe refractometer. Results from the characterization will determine the proper synthesis parameters for the elaboration of tunable refractive surfaces for potential applications in robotics.

  7. Glaucoma Diagnostic Ability of the Optical Coherence Tomography Angiography Vessel Density Parameters.

    Science.gov (United States)

    Chung, Jae Keun; Hwang, Young Hoon; Wi, Jae Min; Kim, Mijin; Jung, Jong Jin

    2017-11-01

    To investigate the glaucoma diagnostic abilities of vessel density parameters as determined by optical coherence tomography (OCT) angiography in different stages of glaucoma. A total of 113 healthy eyes and 140 glaucomatous eyes were enrolled. Diagnostic abilities of the OCT vessel density parameters in the optic nerve head (ONH), peripapillary, and macular regions were evaluated by calculating the area under the receiver operation characteristic curves (AUCs). AUCs of the peripapillary vessel density parameters and circumpapillary retinal nerve fiber layer (RNFL) thickness were compared. OCT angiography vessel densities in the ONH, peripapillary, and macular regions in the glaucomatous eyes were significantly lower than those in the healthy eyes (P glaucoma detection. The peripapillary vessel density parameters showed similar AUCs with the corresponding sectoral RNFL thickness (P > 0.05). However, in the early stage of glaucoma, the AUCs of the inferotemporal and temporal peripapillary vessel densities were significantly lower than that of the RNFL thickness (P glaucoma diagnostic ability with circumpapillary RNFL thickness, in the early stage, the vessel density parameters showed limited clinical value.

  8. Resting-state functional connectivity assessed with two diffuse optical tomographic systems.

    Science.gov (United States)

    Niu, Haijing; Khadka, Sabin; Tian, Fenghua; Lin, Zi-Jing; Lu, Chunming; Zhu, Chaozhe; Liu, Hanli

    2011-04-01

    Functional near-infrared spectroscopy (fNIRS) is recently utilized as a new approach to assess resting-state functional connectivity (RSFC) in the human brain. For any new technique or new methodology, it is necessary to be able to replicate similar experiments using different instruments in order to establish its liability and reproducibility. We apply two different diffuse optical tomographic (DOT) systems (i.e., DYNOT and CW5), with various probe arrangements to evaluate RSFC in the sensorimotor cortex by utilizing a previously published experimental protocol and seed-based correlation analysis. Our results exhibit similar spatial patterns and strengths in RSFC between the bilateral motor cortexes. The consistent observations are obtained from both DYNOT and CW5 systems, and are also in good agreement with the previous fNIRS study. Overall, we demonstrate that the fNIRS-based RSFC is reproducible by various DOT imaging systems among different research groups, enhancing the confidence of neuroscience researchers and clinicians to utilize fNIRS for future applications.

  9. Growth and optical properties of silver nanostructures obtained on connected anodic aluminum oxide templates

    Science.gov (United States)

    Giallongo, G.; Durante, C.; Pilot, R.; Garoli, D.; Bozio, R.; Romanato, F.; Gennaro, A.; Rizzi, G. A.; Granozzi, G.

    2012-08-01

    Ag nanostructures are grown by AC electrodeposition on anodic alumina oxide (AAO) connected membranes acting as templates. Depending on the thickness of the template and on the voltage applied during the growth process, different Ag nanostructures with different optical properties are obtained. When AAO membranes about 1 μm thick are used, the Ag nanostructures consist in Ag nanorods, at the bottom of the pores, and Ag nanotubes departing from the nanorods and filling the pores almost for the whole length. When AAO membranes about 3 μm thick are used, the nanostructures are Ag spheroids, at the bottom of the pores, and Ag nanowires that do not reach the upper part of the alumina pores. The samples are characterized by angle resolved x-ray photoelectron spectroscopy, scanning electron microscopy and UV-vis and Raman spectroscopies. A simple NaOH etching procedure, followed by sonication in ethanol, allows one to obtain an exposed ordered array of Ag nanorods, suitable for surface-enhanced Raman spectroscopy, while in the other case (3 μm thick AAO membranes) the sample can be used in localized surface plasmon resonance sensing.

  10. Growth and optical properties of silver nanostructures obtained on connected anodic aluminum oxide templates

    International Nuclear Information System (INIS)

    Giallongo, G; Durante, C; Pilot, R; Bozio, R; Gennaro, A; Rizzi, G A; Granozzi, G; Garoli, D; Romanato, F

    2012-01-01

    Ag nanostructures are grown by AC electrodeposition on anodic alumina oxide (AAO) connected membranes acting as templates. Depending on the thickness of the template and on the voltage applied during the growth process, different Ag nanostructures with different optical properties are obtained. When AAO membranes about 1 μm thick are used, the Ag nanostructures consist in Ag nanorods, at the bottom of the pores, and Ag nanotubes departing from the nanorods and filling the pores almost for the whole length. When AAO membranes about 3 μm thick are used, the nanostructures are Ag spheroids, at the bottom of the pores, and Ag nanowires that do not reach the upper part of the alumina pores. The samples are characterized by angle resolved x-ray photoelectron spectroscopy, scanning electron microscopy and UV–vis and Raman spectroscopies. A simple NaOH etching procedure, followed by sonication in ethanol, allows one to obtain an exposed ordered array of Ag nanorods, suitable for surface-enhanced Raman spectroscopy, while in the other case (3 μm thick AAO membranes) the sample can be used in localized surface plasmon resonance sensing. (paper)

  11. Priority design parameters of industrialized optical fiber sensors in civil engineering

    Science.gov (United States)

    Wang, Huaping; Jiang, Lizhong; Xiang, Ping

    2018-03-01

    Considering the mechanical effects and the different paths for transferring deformation, optical fiber sensors commonly used in civil engineering have been systematically classified. Based on the strain transfer theory, the relationship between the strain transfer coefficient and allowable testing error is established. The proposed relationship is regarded as the optimal control equation to obtain the optimal value of sensors that satisfy the requirement of measurement precision. Furthermore, specific optimization design methods and priority design parameters of the classified sensors are presented. This research indicates that (1) strain transfer theory-based optimization design method is much suitable for the sensor that depends on the interfacial shear stress to transfer the deformation; (2) the priority design parameters are bonded (sensing) length, interfacial bonded strength, elastic modulus and radius of protective layer and thickness of adhesive layer; (3) the optimization design of sensors with two anchor pieces at two ends is independent of strain transfer theory as the strain transfer coefficient can be conveniently calibrated by test, and this kind of sensors has no obvious priority design parameters. Improved calibration test is put forward to enhance the accuracy of the calibration coefficient of end-expanding sensors. By considering the practical state of sensors and the testing accuracy, comprehensive and systematic analyses on optical fiber sensors are provided from the perspective of mechanical actions, which could scientifically instruct the application design and calibration test of industrialized optical fiber sensors.

  12. Strain effects on the optical parameters of quantum dots nanocrystals employed in biomedical applications

    International Nuclear Information System (INIS)

    Liaparinos, P.F.

    2014-01-01

    The purpose of this study was to perform the influence of the strain (lattice and radius) effects on the optical parameters of nanocrystals for use in medical imaging instrumentation technology. The present manuscript involved (a) quantum dots (QD) based nanophosphors with particle size 3–5 nm in diameter, (b) dielectric constants (core) of nanophosphors in the range 2–4, and (c) the whole portion of the electromagnetic spectrum visible to the human eye, 400–700 nm. Lattice strain effects on the optical properties were evaluated by the modification of the bulk dielectric function using a Drude–Sommerfeld model for the free or conduction electrons, and a core term representing the bound electrons. The Mie scattering theory, was used to predict the shifted optical parameters. Results showed that (i) lattice stain reduces the real part (n) of refractive index, (ii) the reduction of n becomes higher with the increase of ε core (ω) and (iii) no significant variations on n were observed under the variability of incident light wavelength (400–700 nm). Light wavelength was found to affect significantly the imaginary part (k) of the complex refractive index. In addition, the radius strain (i) decreases the light extinction coefficient, m ext , (ii) increases the anisotropy factor, g and (iii) increases the light absorption probability, p. However, in cases of ε core (ω)=2, radius strain of 5% seems to present slightly higher p values than the cases of radius strain 10%. The present investigation found that the modification on the optical parameters enhances the utilization of quantom-dots luminescent nanomaterial in optical diffusion studies with requirements of high sensitivity (such as nuclear medical imaging modalities) rather than of high light spatial resolution (such as X-ray projection medical imaging systems). -- Highlights: • The strain effects on the optical parameters of quantum dots were examined. • Light wavelength affects significantly the

  13. On optical detection of densely labeled synapses in neuropil and mapping connectivity with combinatorially multiplexed fluorescent synaptic markers.

    Directory of Open Access Journals (Sweden)

    Yuriy Mishchenko

    Full Text Available We propose a new method for mapping neural connectivity optically, by utilizing Cre/Lox system Brainbow to tag synapses of different neurons with random mixtures of different fluorophores, such as GFP, YFP, etc., and then detecting patterns of fluorophores at different synapses using light microscopy (LM. Such patterns will immediately report the pre- and post-synaptic cells at each synaptic connection, without tracing neural projections from individual synapses to corresponding cell bodies. We simulate fluorescence from a population of densely labeled synapses in a block of hippocampal neuropil, completely reconstructed from electron microscopy data, and show that high-end LM is able to detect such patterns with over 95% accuracy. We conclude, therefore, that with the described approach neural connectivity in macroscopically large neural circuits can be mapped with great accuracy, in scalable manner, using fast optical tools, and straightforward image processing. Relying on an electron microscopy dataset, we also derive and explicitly enumerate the conditions that should be met to allow synaptic connectivity studies with high-resolution optical tools.

  14. Connections between borehole geophysical parameters of the quality of cement raw materials

    International Nuclear Information System (INIS)

    Szabo, L.; Illes, A.

    1978-01-01

    The raw materials for the cement industry are prospected - according to the recommendations of national authorities - by geophysical methods, too. These include not the determination of the deposit boundary, but also an estimation of the quality of limestone and clay from the point of cement manufacture. No forerunners of such tests exist, so new methods were elaborated. After 12 years of site tests it was found that the correlation between laboratory quality tests and certain geophysical parameters of clay deposits is fair but less close in case of limestone deposits. (author)

  15. Connecting Majorana phases to the geometric parameters of the Majorana unitarity triangle in a neutrino mass matrix model

    Science.gov (United States)

    Verma, Surender; Bhardwaj, Shankita

    2018-05-01

    We have investigated a possible connection between the Majorana phases and geometric parameters of Majorana unitarity triangle (MT) in two-texture zero neutrino mass matrix. Such analytical relations can, also, be obtained for other theoretical models viz. hybrid textures, neutrino mass matrix with vanishing minors and have profound implications for geometric description of C P violation. As an example, we have considered the two-texture zero neutrino mass model to obtain a relation between Majorana phases and MT parameters that may be probed in various lepton number violating processes. In particular, we find that Majorana phases depend on only one of the three interior angles of the MT in each class of two-texture zero neutrino mass matrix. We have also constructed the MT for class A , B , and C neutrino mass matrices. Nonvanishing areas and nontrivial orientations of these Majorana unitarity triangles indicate nonzero C P violation as a generic feature of this class of mass models.

  16. Retrieving the optical parameters of biological tissues using diffuse reflectance spectroscopy and Fourier series expansions. I. theory and application.

    Science.gov (United States)

    Muñoz Morales, Aarón A; Vázquez Y Montiel, Sergio

    2012-10-01

    The determination of optical parameters of biological tissues is essential for the application of optical techniques in the diagnosis and treatment of diseases. Diffuse Reflection Spectroscopy is a widely used technique to analyze the optical characteristics of biological tissues. In this paper we show that by using diffuse reflectance spectra and a new mathematical model we can retrieve the optical parameters by applying an adjustment of the data with nonlinear least squares. In our model we represent the spectra using a Fourier series expansion finding mathematical relations between the polynomial coefficients and the optical parameters. In this first paper we use spectra generated by the Monte Carlo Multilayered Technique to simulate the propagation of photons in turbid media. Using these spectra we determine the behavior of Fourier series coefficients when varying the optical parameters of the medium under study. With this procedure we find mathematical relations between Fourier series coefficients and optical parameters. Finally, the results show that our method can retrieve the optical parameters of biological tissues with accuracy that is adequate for medical applications.

  17. Optimization of the Hot Forging Processing Parameters for Powder Metallurgy Fe-Cu-C Connecting Rods Based on Finite Element Simulation

    Science.gov (United States)

    Li, Fengxian; Yi, Jianhong; Eckert, Jürgen

    2017-12-01

    Powder forged connecting rods have the problem of non-uniform density distributions because of their complex geometric shape. The densification behaviors of powder metallurgy (PM) connecting rod preforms during hot forging processes play a significant role in optimizing the connecting rod quality. The deformation behaviors of a connecting rod preform, a Fe-3Cu-0.5C (wt pct) alloy compacted and sintered by the powder metallurgy route (PM Fe-Cu-C), were investigated using the finite element method, while damage and friction behaviors of the material were considered in the complicated forging process. The calculated results agree well with the experimental results. The relationship between the processing parameters of hot forging and the relative density of the connecting rod was revealed. The results showed that the relative density of the hot forged connecting rod at the central shank changed significantly compared with the relative density at the big end and at the small end. Moreover, the relative density of the connecting rod was sensitive to the processing parameters such as the forging velocity and the initial density of the preform. The optimum forging processing parameters were determined and presented by using an orthogonal design method. This work suggests that the processing parameters can be optimized to prepare a connecting rod with uniform density distribution and can help to better meet the requirements of the connecting rod industry.

  18. Thermally induced changes of optical and vital parameters in human cancer cells

    Science.gov (United States)

    Dressler, C.; Schwandt, D.; Beuthan, J.; Mildaziene, V.; Zabarylo, U.; Minet, O.

    2010-11-01

    Minimally invasive laser-induced thermotherapy (LITT) presents an alternative method to conventional tumor therapeutically interventions, such as surgery, chemotherapy, radiotherapy or nuclear medicine. Optical tissue characteristics of tumor cells and their heat-induced changes are essential issues for controlling LITT progressions. Therefore, it is indispensable to exactly know the absorption coefficient μa, the scattering coefficient μs and the anisotropy factor g as well as their changes under rising temperatures in order to simulate the treatment parameters successfully. Optical parameters of two different cancer model tissues - breast cancer cells species MX1 and colon cancer cells species CX1 - were measured in the spectral range 400 - 1100 nm as well as in the temperature range 37 - 60°C. The absorption coefficient of both cell species was low throughout the spectral range analyzed, while μs of both species rose with increasing temperatures. The anisotropy factor g however dropped for both tissues with increasing temperatures. Light scatterings inside tissues proceeded continuously forward for all species tested. It was demonstrated that optical tissue properties undergo significant changes along with the vital status of the cells when the temperature increases.

  19. γ - irradiation induced effect on the optical parameters of Cu10 Se90 thin films

    International Nuclear Information System (INIS)

    Abu EL-Fadl, A.; Hafiz, M. M.; Aashour, A.S.; Wakaad, M.M.

    2007-01-01

    The optical constants of Cu 10 SE 90 Chalcogenide films successfully deposited by evaporation coating technique have been measured. The absorption coefficient (a) for the as-deposited or after being γ-irradiation at various doses have been computed in the spectral wavelength range 400-900 nm from the transmittance (T) and reflectance (R) measurements of normally-incident light. Both irradiated and as-prepared films showed direct transition. The direct optical band gaps of the films were found to decrease from 2.017 for as prepared to 1.941 eV for γ-irradiation at 190 kGy doses. The width of the tails of localized states E e were calculated and found to be increasing after γ-irradiation. The effects of the γ-irradiation on the refractive index n and extinction coefficient k were studied. Other optical parameters (ε I , ε 2 were calculated at different γ-irradiation doses the obtained values of both ε 1 and ε 2 were found to be incident light and γ-doses dependent. The effect of γ-irradiation on the high-frequency dielectric constant (ε ∞ ) and carrier concentration (N/m * ) is also studied. The change on the degree of disorder as will as the radiation-induced defect changes applied to explain the radiation effects on nature of optical properties Cu 10 SE 90 glasses

  20. Nonlinear optical parameters of nanocrystalline AZO thin film measured at different substrate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Jilani, Asim, E-mail: asim.jilane@gmail.com [Centre of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-wahab, M.Sh [Centre of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni -Suef University, Beni-Suef (Egypt); Al-ghamdi, Attieh A. [Centre of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Dahlan, Ammar sadik [Department of architecture, faculty of environmental design, King Abdulaziz University, Jeddah (Saudi Arabia); Yahia, I.S. [Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Nano-Science & Semiconductor Labs, Department of Physics, Faculty of Education, Ain Shams University, Roxy, 11757 Cairo (Egypt)

    2016-01-15

    The 2.2 wt% of aluminum (Al)-doped zinc oxide (AZO) transparent and preferential c-axis oriented thin films were prepared by using radio frequency (DC/RF) magnetron sputtering at different substrate temperature ranging from room temperature to 200 °C. For structural analysis, X-ray Diffraction (XRD) and Atomic Force Electron Microscope (AFM) was used for morphological studies. The optical parameters such as, optical energy gap, refractive index, extinction coefficient, dielectric loss, tangent loss, first and third order nonlinear optical properties of transparent films were investigated. High transmittance above 90% and highly homogeneous surface were observed in all samples. The substrate temperature plays an important role to get the best transparent conductive oxide thin films. The substrate temperature at 150 °C showed the growth of highly transparent AZO thin film. Energy gap increased with the increased in substrate temperature of Al doped thin films. Dielectric constant and loss were found to be photon energy dependent with substrate temperature. The change in substrate temperature of Al doped thin films also affect the non-liner optical properties of thin films. The value of χ{sup (3)} was found to be changed with the grain size of the thin films that directly affected by the substrate temperature of the pure and Al doped ZnO thin films.

  1. Theoretical and experimental evaluation of piezo-optic parameters and photoelastic constant in tetragonal PWO.

    Science.gov (United States)

    Natali, Pier Paolo; Montalto, Luigi; Daví, Fabrizio; Mengucci, Paolo; Ciriaco, Andrea; Paone, Nicola; Rinaldi, Daniele

    2018-02-01

    The tetragonal PbWO 4 (PWO) is one of the most important scintillating crystals, being used both in the Compact Muon Solenoid (CMS) experiment at the European Organization for Nuclear Research (CERN) and in the PANDA project at the Facility for Antiproton and Ion Research (FAIR). Light yield and other relevant scintillation properties depend, among many factors, also on the crystal mechanical quality. Accordingly, a detailed knowledge of crystal piezo-optic properties is a mandatory step toward understanding elasto-optic behavior and performing crystal quality control. In this paper, we evaluate for the first time, to the best of our knowledge, by means of both photoelastic and x-ray measurements, some components of the piezo-optic tensor; moreover, when the crystal is acted upon by a uniaxial stress, we obtain an evaluation for the rotation angle of the optic plane under stress as well as the photoelastic constant. These parameters are necessary to detect the residual stresses within the crystal, if any, and to give an overall quality measure. Such a methodology is in general suitable for any tetragonal crystals.

  2. Traffic grooming in WDM optical network with grooming resources at Max Connectivity nodes

    Science.gov (United States)

    Paul, Partha; Rawat, Balbeer Singh; Ghorai, S. K.

    2012-12-01

    In this paper, we propose Max Connectivity grooming in WDM mesh networks under static lightpath connection requests. The grooming and wavelength conversion resources are placed at the nodes having maximum connections. We propose a heuristic genetic algorithm (GA) model to solve grooming, routing and wavelength assignment. The GA algorithm has been used to optimize the cost of grooming and wavelength conversion resources. The blocking probability has been investigated under different lightpath connections. The performance of Max Connectivity grooming has been compared with other grooming policies. Our results indicate the improvement of resource utilization with minimum blocking probability.

  3. Characterization of IP Flows Eligible for Lambda-Connections in Optical Networks

    NARCIS (Netherlands)

    Fioreze, Tiago; Oude Wolbers, Mattijs; van de Meent, R.; Pras, Aiko

    2008-01-01

    The advance on data transmission in optical networks has allowed data forwarding decisions to be taken at multiple levels in the protocol stack (e.g., at network and optical levels). With such capability, big IP flows can be moved from the network level and switched completely at the optical level

  4. CONNECTION BETWEEN DYNAMICALLY DERIVED INITIAL MASS FUNCTION NORMALIZATION AND STELLAR POPULATION PARAMETERS

    International Nuclear Information System (INIS)

    McDermid, Richard M.; Cappellari, Michele; Bayet, Estelle; Bureau, Martin; Davies, Roger L.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Duc, Pierre-Alain; Crocker, Alison F.; Davis, Timothy A.; De Zeeuw, P. T.; Emsellem, Eric; Kuntschner, Harald; Khochfar, Sadegh; Krajnović, Davor; Morganti, Raffaella; Oosterloo, Tom; Naab, Thorsten

    2014-01-01

    We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS 3D project. We study trends between our dynamically derived IMF normalization α dyn ≡ (M/L) stars /(M/L) Salp and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [α/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalization of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of α dyn at a given population parameter. As a result, we find weak α dyn -[α/Fe] and α dyn –Age correlations and no significant α dyn –[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalization via the low-mass star demographics inferred through stellar spectral analysis

  5. CONNECTION BETWEEN DYNAMICALLY DERIVED INITIAL MASS FUNCTION NORMALIZATION AND STELLAR POPULATION PARAMETERS

    Energy Technology Data Exchange (ETDEWEB)

    McDermid, Richard M. [Department of Physics and Astronomy, Macquarie University, Sydney NSW 2109 (Australia); Cappellari, Michele; Bayet, Estelle; Bureau, Martin; Davies, Roger L. [Sub-Department of Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom); Alatalo, Katherine [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Blitz, Leo [Department of Astronomy, Campbell Hall, University of California, Berkeley, CA 94720 (United States); Bois, Maxime [Observatoire de Paris, LERMA and CNRS, 61 Av. de l' Observatoire, F-75014 Paris (France); Bournaud, Frédéric; Duc, Pierre-Alain [Laboratoire AIM Paris-Saclay, CEA/IRFU/SAp- CNRS-Université Paris Diderot, F-91191 Gif-sur-Yvette Cedex (France); Crocker, Alison F. [Ritter Astrophysical Observatory, University of Toledo, Toledo, OH 43606 (United States); Davis, Timothy A.; De Zeeuw, P. T.; Emsellem, Eric; Kuntschner, Harald [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Khochfar, Sadegh [Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Krajnović, Davor [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Morganti, Raffaella; Oosterloo, Tom [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Naab, Thorsten, E-mail: richard.mcdermid@mq.edu.au [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching (Germany); and others

    2014-09-10

    We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS{sup 3D} project. We study trends between our dynamically derived IMF normalization α{sub dyn} ≡ (M/L){sub stars}/(M/L){sub Salp} and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [α/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalization of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of α{sub dyn} at a given population parameter. As a result, we find weak α{sub dyn}-[α/Fe] and α{sub dyn} –Age correlations and no significant α{sub dyn} –[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalization via the low-mass star demographics inferred through stellar spectral analysis.

  6. Connection between Dynamically Derived Initial Mass Function Normalization and Stellar Population Parameters

    Science.gov (United States)

    McDermid, Richard M.; Cappellari, Michele; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

    2014-09-01

    We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS3D project. We study trends between our dynamically derived IMF normalization αdyn ≡ (M/L)stars/(M/L)Salp and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [α/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalization of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of αdyn at a given population parameter. As a result, we find weak αdyn-[α/Fe] and αdyn -Age correlations and no significant αdyn -[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalization via the low-mass star demographics inferred through stellar spectral analysis.

  7. Ellipsometry study of optical parameters of AgIn5S8 crystals

    Science.gov (United States)

    Isik, Mehmet; Gasanly, Nizami

    2015-12-01

    AgIn5S8 crystals grown by Bridgman method were characterized for optical properties by ellipsometry measurements. Spectral dependence of optical parameters; real and imaginary parts of the pseudodielectric function, pseudorefractive index, pseudoextinction coefficient, reflectivity and absorption coefficient were obtained from ellipsometry experiments carried out in the 1.2-6.2 eV range. Direct band gap energy of 1.84 eV was found from the analysis of absorption coefficient vs. photon energy. The oscillator energy, dispersion energy and zero-frequency refractive index, high-frequency dielectric constant values were found from the analysis of the experimental data using Wemple-DiDomenico and Spitzer-Fan models. Crystal structure and atomic composition ratio of the constituent elements in the AgIn5S8 crystal were revealed from structural characterization techniques of X-ray diffraction and energy dispersive spectroscopy.

  8. Ellipsometry study of optical parameters of AgIn{sub 5}S{sub 8} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Isik, Mehmet, E-mail: mehmet.isik@atilim.edu.tr [Department of Electrical and Electronics Engineering, Atilim University, 06836 Ankara (Turkey); Gasanly, Nizami [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Virtual International Scientific Research Centre, Baku State University, 1148 Baku (Azerbaijan)

    2015-12-01

    AgIn{sub 5}S{sub 8} crystals grown by Bridgman method were characterized for optical properties by ellipsometry measurements. Spectral dependence of optical parameters; real and imaginary parts of the pseudodielectric function, pseudorefractive index, pseudoextinction coefficient, reflectivity and absorption coefficient were obtained from ellipsometry experiments carried out in the 1.2–6.2 eV range. Direct band gap energy of 1.84 eV was found from the analysis of absorption coefficient vs. photon energy. The oscillator energy, dispersion energy and zero-frequency refractive index, high-frequency dielectric constant values were found from the analysis of the experimental data using Wemple-DiDomenico and Spitzer-Fan models. Crystal structure and atomic composition ratio of the constituent elements in the AgIn{sub 5}S{sub 8} crystal were revealed from structural characterization techniques of X-ray diffraction and energy dispersive spectroscopy.

  9. Influence of experimental parameters inherent to optical fibers on Quantum Key Distribution, the protocol BB84

    Directory of Open Access Journals (Sweden)

    L. Bouchoucha

    2018-03-01

    Full Text Available In this work, we represent the principle of quantum cryptography (QC that is based on fundamental laws of quantum physics. QC or Quantum Key Distribution (QKD uses various protocols to exchange a secret key between two communicating parties. This research paper focuses and examines the quantum key distribution by using the protocol BB84 in the case of encoding on the single-photon polarization and shows the influence of optical components parameters on the quantum key distribution. We also introduce Quantum Bit Error Rate (QBER to better interpret our results and show its relationship with the intrusion of the eavesdropper called Eve on the optical channel to exploit these vulnerabilities.

  10. Sensitive zone parameters and curvature radius evaluation for polymer optical fiber curvature sensors

    Science.gov (United States)

    Leal-Junior, Arnaldo G.; Frizera, Anselmo; José Pontes, Maria

    2018-03-01

    Polymer optical fibers (POFs) are suitable for applications such as curvature sensors, strain, temperature, liquid level, among others. However, for enhancing sensitivity, many polymer optical fiber curvature sensors based on intensity variation require a lateral section. Lateral section length, depth, and surface roughness have great influence on the sensor sensitivity, hysteresis, and linearity. Moreover, the sensor curvature radius increase the stress on the fiber, which leads on variation of the sensor behavior. This paper presents the analysis relating the curvature radius and lateral section length, depth and surface roughness with the sensor sensitivity, hysteresis and linearity for a POF curvature sensor. Results show a strong correlation between the decision parameters behavior and the performance for sensor applications based on intensity variation. Furthermore, there is a trade-off among the sensitive zone length, depth, surface roughness, and curvature radius with the sensor desired performance parameters, which are minimum hysteresis, maximum sensitivity, and maximum linearity. The optimization of these parameters is applied to obtain a sensor with sensitivity of 20.9 mV/°, linearity of 0.9992 and hysteresis below 1%, which represent a better performance of the sensor when compared with the sensor without the optimization.

  11. Evaluation of third order nonlinear optical parameters of CdS/PVA nanocomposite

    International Nuclear Information System (INIS)

    Sharma, Mamta; Tripathi, S. K.

    2015-01-01

    CdS nanoparticles dispersed in PVA are prepared by Chemical method at room temperature. The nonlinear optical parameters such as nonlinear absorption (β), nonlinear refractive index (n 2 ) and nonlinear susceptibility (χ 3 ) are calculated for this sample by using Z-scan technique. CdS/PVA samples show the two photon absorption mechanism. The third order nonlinear susceptibility is calculated from n 2 and β and is found to be of the order of 10 −7 – 10 −8 m 2 /V 2 . The larger value of third order nonlinear susceptibility is due to dielectric and quantum confinement effect

  12. A real-time measurement system for parameters of live biology metabolism process with fiber optics

    Science.gov (United States)

    Tao, Wei; Zhao, Hui; Liu, Zemin; Cheng, Jinke; Cai, Rong

    2010-08-01

    Energy metabolism is one of the basic life activities of cellular in which lactate, O2 and CO2 will be released into the extracellular environment. By monitoring the quantity of these parameters, the mitochondrial performance will be got. A continuous measurement system for the concentration of O2, CO2 and PH value is introduced in this paper. The system is made up of several small-sized fiber optics biosensors corresponding to the container. The setup of the system and the principle of measurement of several parameters are explained. The setup of the fiber PH sensor based on principle of light absorption is also introduced in detail and some experimental results are given. From the results we can see that the system can measure the PH value precisely suitable for cell cultivation. The linear and repeatable accuracies are 3.6% and 6.7% respectively, which can fulfill the measurement task.

  13. Control of optical transport parameters of 'porous medium – supercritical fluid' systems

    Energy Technology Data Exchange (ETDEWEB)

    Zimnyakov, D A; Ushakova, O V; Yuvchenko, S A [Yuri Gagarin State Technical University of Saratov, Saratov (Russian Federation); Bagratashvili, V N [M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2015-11-30

    The possibility of controlling optical transport parameters (in particular, transport scattering coefficient) of porous systems based on polymer fibres, saturated with carbon dioxide in different phase states (gaseous, liquid and supercritical) has been experimentally studied. An increase in the pressure of the saturating medium leads to a rise of its refractive index and, correspondingly, the diffuse-transmission coefficient of the system due to the decrease in the transport scattering coefficient. It is shown that, in the case of subcritical saturating carbon dioxide, the small-angle diffuse transmission of probed porous layers at pressures close to the saturated vapour pressure is determined by the effect of capillary condensation in pores. The immersion effect in 'porous medium – supercritical fluid' systems, where the fluid pressure is used as a control parameter, is considered. The results of reconstructing the values of transport scattering coefficient of probed layers for different refractive indices of a saturating fluid are presented. (radiation scattering)

  14. Transient radiation responses of optical fibers: influence of MCVD process parameters

    International Nuclear Information System (INIS)

    Girard, Sylvain; Alessi, Antonino; Boukenter, Aziz; Ouerdane, Y.; Marcandella, Claude; Richard, Nicolas; Paillet, Philippe; Gaillardin, Marc; Raine, Melanie

    2012-01-01

    A dedicated set of fibers elaborated via the Modified Chemical Vapor Deposition (MCVD) technique is used to study the influence of composition and drawing parameters on their responses to an X-ray pulse representative of the radiation environments associated with Megajoule class lasers. These canonical fibers were designed to highlight the impact of these parameters on the amplitude and kinetics of the transient pulsed X-ray Radiation Induced Attenuation (RIA) at room temperature. From pre-forms differing by their core composition, three optical fibers were elaborated by varying the tension and speed during the drawing process. No or only slight RIA change results from the tested variations in drawing process parameters of Ge-doped, F-doped, and pure-silica-core fibers. This study reveals that the drawing process is not the main parameter to be optimized in order to enhance the radiation tolerance of MCVD specialty optical fibers for the LMJ harsh environment. From the hardness assurance point of view, a specialty fiber sufficiently tolerant to this environment should be robust against changes in the drawing process. The origins of the RIA observed in the different fibers are discussed on the basis of spectral decomposition of their measured RIA spectra, using sets of defects from the literature and related to the different core dopants. This analysis highlights the limits of the well-known defect set to reproduce the RIA above 1 for Ge-doped fibers whereas self-trapped holes and chlorine-related species seem responsible for the transient responses of pure-silica-core and F-doped fibers. (authors)

  15. CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces

    Science.gov (United States)

    2002-09-30

    CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces Alan W. Decho Department...TITLE AND SUBTITLE CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces 5a. CONTRACT...structures produced by bacteria. Their growth appears to depend on biofilm processes and light distributions ( photosynthesis ). Therefore, the data acquired

  16. Low loss hollow optical-waveguide connection from atmospheric pressure to ultra-high vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Ermolov, A.; Mak, K. F.; Tani, F.; Hölzer, P.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Russell, P. St. J. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Department of Physics, University of Erlangen-Nuremberg, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany)

    2013-12-23

    A technique for optically accessing ultra-high vacuum environments, via a photonic-crystal fiber with a long small hollow core, is described. The small core and the long bore enable a pressure ratio of over 10{sup 8} to be maintained between two environments, while permitting efficient and unimpeded delivery of light, including ultrashort optical pulses. This delivery can be either passive or can encompass nonlinear optical processes such as optical pulse compression, deep UV generation, supercontinuum generation, or other useful phenomena.

  17. Resonance Damping and Parameter Design Method for LCL-LC Filter Interfaced Grid-Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Li, Zipeng; Jiang, Aiting; Shen, Pan

    2016-01-01

    , this paper presents a systematic design method for the LCL-LC filtered grid-connected photovoltaic (PV) system. With this method, controller parameters and the active damping feedback coefficient are easily obtained by specifying the system stability and dynamic performance indices, and it is more convenient......-frequency harmonics attenuation ability, but the resonant problem affects the system stability remarkably. In this paper, active damping based on the capacitor voltage feedback is proposed using the concept of the equivalent virtual impedance in parallel with the capacitor. With the consideration of system delay...... to optimize the system performance according to the predefined satisfactory region. Finally, the simulation results are presented to validate the proposed design method and control scheme....

  18. Ametropia, retinal anatomy, and OCT abnormality patterns in glaucoma. 2. Impacts of optic nerve head parameters

    Science.gov (United States)

    Baniasadi, Neda; Wang, Mengyu; Wang, Hui; Jin, Qingying; Elze, Tobias

    2017-12-01

    Clinicians use retinal nerve fiber layer thickness (RNFLT) measured by optical coherence tomography (OCT) as an adjunct to glaucoma diagnosis. Ametropia is accompanied by changes to the optic nerve head (ONH), which may affect how OCT machines mark RNFLT measurements as abnormal. These changes in abnormality patterns may bias glaucoma diagnosis. Here, we investigate the relationship between OCT abnormality patterns and the following ONH-related and ametropia-associated parameters on 421 eyes of glaucoma patients: optic disc tilt and torsion, central retinal vessel trunk location (CRVTL), and nasal and temporal retinal curvature adjacent to ONH, quantified as nasal/temporal slopes of the inner limiting membrane. We applied multivariate logistic regression with abnormality marks as regressands to 40,401 locations of the peripapillary region and generated spatial maps of locations of false positive/negative abnormality marks independent of glaucoma severity. Effects of torsion and temporal slope were negligible. The effect of tilt could be explained by covariation with ametropia. For CRVTL/nasal slope, abnormality pattern shifts at 7.2%/23.5% of the peripapillary region were detected, respectively, independent of glaucoma severity and ametropia. Therefore, CRVTL and nasal curvature should be included in OCT RNFLT norms. Our spatial location maps may aid clinicians to improve diagnostic accuracy.

  19. New types of 2×2 wavelength-switching blocks for optical cross-connects

    DEFF Research Database (Denmark)

    Liu, Fenghai; Zheng, Xueyan; Pedersen, Rune Johan Skullerud

    2001-01-01

    Two types of modular 2×2 wavelength-switching blocks are proposed in this letter. A 2×2 fixed wavelength-switching block can cross-connect two fixed channels between two fibers, and a 2×2 tunable wavelength-switching block can cross-connect any two channels between two fibers. These modular blocks...

  20. A Novel Artificial Fish Swarm Algorithm for Recalibration of Fiber Optic Gyroscope Error Parameters

    Directory of Open Access Journals (Sweden)

    Yanbin Gao

    2015-05-01

    Full Text Available The artificial fish swarm algorithm (AFSA is one of the state-of-the-art swarm intelligent techniques, which is widely utilized for optimization purposes. Fiber optic gyroscope (FOG error parameters such as scale factors, biases and misalignment errors are relatively unstable, especially with the environmental disturbances and the aging of fiber coils. These uncalibrated error parameters are the main reasons that the precision of FOG-based strapdown inertial navigation system (SINS degraded. This research is mainly on the application of a novel artificial fish swarm algorithm (NAFSA on FOG error coefficients recalibration/identification. First, the NAFSA avoided the demerits (e.g., lack of using artificial fishes’ pervious experiences, lack of existing balance between exploration and exploitation, and high computational cost of the standard AFSA during the optimization process. To solve these weak points, functional behaviors and the overall procedures of AFSA have been improved with some parameters eliminated and several supplementary parameters added. Second, a hybrid FOG error coefficients recalibration algorithm has been proposed based on NAFSA and Monte Carlo simulation (MCS approaches. This combination leads to maximum utilization of the involved approaches for FOG error coefficients recalibration. After that, the NAFSA is verified with simulation and experiments and its priorities are compared with that of the conventional calibration method and optimal AFSA. Results demonstrate high efficiency of the NAFSA on FOG error coefficients recalibration.

  1. A novel artificial fish swarm algorithm for recalibration of fiber optic gyroscope error parameters.

    Science.gov (United States)

    Gao, Yanbin; Guan, Lianwu; Wang, Tingjun; Sun, Yunlong

    2015-05-05

    The artificial fish swarm algorithm (AFSA) is one of the state-of-the-art swarm intelligent techniques, which is widely utilized for optimization purposes. Fiber optic gyroscope (FOG) error parameters such as scale factors, biases and misalignment errors are relatively unstable, especially with the environmental disturbances and the aging of fiber coils. These uncalibrated error parameters are the main reasons that the precision of FOG-based strapdown inertial navigation system (SINS) degraded. This research is mainly on the application of a novel artificial fish swarm algorithm (NAFSA) on FOG error coefficients recalibration/identification. First, the NAFSA avoided the demerits (e.g., lack of using artificial fishes' pervious experiences, lack of existing balance between exploration and exploitation, and high computational cost) of the standard AFSA during the optimization process. To solve these weak points, functional behaviors and the overall procedures of AFSA have been improved with some parameters eliminated and several supplementary parameters added. Second, a hybrid FOG error coefficients recalibration algorithm has been proposed based on NAFSA and Monte Carlo simulation (MCS) approaches. This combination leads to maximum utilization of the involved approaches for FOG error coefficients recalibration. After that, the NAFSA is verified with simulation and experiments and its priorities are compared with that of the conventional calibration method and optimal AFSA. Results demonstrate high efficiency of the NAFSA on FOG error coefficients recalibration.

  2. Photo-induced changes of silicate glasses optical parameters at multi-photon laser radiation absorption

    International Nuclear Information System (INIS)

    Efimov, O.M.; Glebov, L.B.; Mekryukov, A.M.

    1995-01-01

    In this paper the results of investigations of the mechanisms of photo-induced changes of alkali-silicate (crown) and lead-silicate (flint) glasses optical parameters upon the exposure to the intense laser radiation, and the basic regularities of these processes are reported. These investigations were performed in Research Center open-quotes S. I. Vavilov State Optical Instituteclose quotes during last 15 years. The kinetics of stable and unstable CC formation and decay, the effect of widely spread impurity ions on these processes, the characteristics of fundamental and impure luminescence, the kinetics of refractive index change under conditions of multi-photon glass matrix excitation, and other properties are considered. On the basis of analysis of received regularities it was shown that the nonlinear coloration of alkali-silicate glasses (the fundamental absorption edge is nearly 6 eV) takes place only as a result of two-photon absorption. Important efforts were aimed at the detection of three- or more photon matrix ionization of these glasses, but they were failed. However it was established that in the lead silicate glasses the long-wave carriers mobility boundary (> 5.6 eV) is placed considerably higher the fundamental absorption edge (∼ 3.5 eV) of material matrix. This results in that the linear color centers formation in the lead silicate glasses is not observed. The coloration of these glasses arises only from the two- or three-photon matrix ionization, and the excitation occurs through virtual states that are placed in the fundamental absorption region. In the report the available mechanisms of photo-induced changes of glasses optical parameters, and some applied aspects of this problem are discussed

  3. Impact of errors in experimental parameters on reconstructed breast images using diffuse optical tomography.

    Science.gov (United States)

    Deng, Bin; Lundqvist, Mats; Fang, Qianqian; Carp, Stefan A

    2018-03-01

    largest deterioration due to cross-talk between signal channels. However, errors in optical images could be effectively controlled when experimental parameters were properly estimated during data acquisition and accounted for in the image processing procedure. Finally, optical images recovered using structural priors were, in general, less susceptible to experimental errors; however, lesion contrasts were more sensitive to errors when tumor locations were used as a priori info. Findings in this simulation study can provide guidelines for system design and operation in optical breast imaging studies.

  4. Evaluation of the Trajectory Sensitivity Analysis of the DFIG Control Parameters in Response to Changes in Wind Speed and the Line Impedance Connection to the Grid DFIG

    Directory of Open Access Journals (Sweden)

    Mehdi Fooladgar

    2015-01-01

    Full Text Available Economic and environmental conditions often make large stations and transmission lines, restrictions are placed. Small and medium-sized production units connected to existing systems as a strategy is in progress. These units are usually near the center of the load placed and distributed generators (DG famous are the DG are allowed types vary, such as induction generators rack squirrel-connected wind turbines, generators fed induction double mounted wind turbines, fuel cells connected to the system by power electronic converters or synchronous generator connected to the turbine combustion [10]. This way sensitivity analysis in systems of distributed generation (DG is assessed. It is shown that the method can detect the effect of control parameters listed wind turbine connected to a double-fed induction generator (DFIG Badoou the impedance of the changing the speed of on the stability of the transmission line useful system invested. The control parameters of the importance of influencing the behavior of DFIG are divided.

  5. Optical Coherence Tomography Parameters in Morbidly Obese Patients Who Underwent Laparoscopic Sleeve Gastrectomy

    Directory of Open Access Journals (Sweden)

    Berna Dogan

    2016-01-01

    Full Text Available Purpose. To investigate changes in optical coherence tomography parameters in morbidly obese patients who had undergone laparoscopic sleeve gastrectomy (LSG. Methods. A total of 41 eyes of 41 morbidly obese patients (BMI ≥ 40 who had undergone LSG were included in study. The topographic optic disc parameters, central macular thickness (CMT, total macular volume (TMV, and retinal ganglion cell layer (RGCL were measured by spectral-domain optical coherence tomography (SD-OCT. Subfoveal choroidal thickness (SFCT was measured by enhanced deep imaging-optical coherence tomography (EDI-OCT. Results. The mean CMT was 237.4±24.5 μm, 239.3±24.1 μm, and 240.4±24.5 μm preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. The mean TMV was 9.88±0.52 mm3, 9.96±0.56 mm3, and 9.99±0.56 mm3 preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. The mean RGCL was 81.2±6.5 μm, 82.7±6.6 μm, and 82.9±6.5 μm preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. The mean SFCT was 309.8±71.8 μm, 331.0±81.4 μm, and 352.7±81.4 μm preoperatively, 3 months postoperatively, and 6 months postoperatively, respectively (p<0.01. No statistically significant differences were found between the preoperative values and 3- and 6-month postoperative values in rim area (p=0.34, disc area (p=0.64, vertical cup/disc ratio (p=0.39, cup volume (p=0.08, or retinal nerve fiber layer (p=0.90. Conclusions. Morbidly obese patients who undergo LSG experience a statistically significant increase in CMT, TMV, SFCT, and RGCL at 3 months and 6 months after surgery.

  6. Evaluating of Tear Meniscus Parameters with Optical Coherent Tomography in Dry-Eye Patients

    Directory of Open Access Journals (Sweden)

    Gülizar Soyugelen Demirok

    2013-08-01

    Full Text Available Purpose: To evaluate the changes in meniscus parameters with optical coherence tomography (OCT after treatment and consider the correlation between the OCT parameters and dry-eye tests. Material and Method: Thirty-two dry-eye patients and 30 healthy individuals were included. Visual acuities, biomicroscopic evaluation, Schirmer-I test, tear-break-up time (T-BUT, and lower-tear meniscus parameters measured with OCT were evaluated. Ocular surface disease index (OSDI was performed. The measurements were repeated on the 10th day and 1st month of the treatment. Lower tear meniscus height (LTMH, depth (LTMD, area (LTMA and α-angle were measured. The tear meniscus parameters of the dry-eye group were compared with the control group before treatment, and the correlation between the dry-eye tests and OCT measurements were evaluated. The change in the results of the dry-eye tests and OCT measurements with treatment were assessed. Results: There was statistically no significant difference between the age and gender of the patients in groups. Before treatment the mean Schirmer-I test, TBUT and OSDI scores were different. The LTMH and LTMA were higher in the control group. In the dry-eye group before treatment, there was a negative correlation between the OSDI score and OCT parameters, however, no meaningful correlation was observed between any other test and OCT parameters. Although there were no change in LTMD and α-angle with treatment, the 1st month values of LTMH and LTMA were significantly higher from the pre-treatment and 10th day values. Discussion: When diagnosing dry-eye, TBUT and OSDI scores were found to be more effective compared to Schirmer-I test for the diagnosis of dry eye. Although not adequate by itself, tear meniscus parameters measured with OCT, LTMH and LTMA, may be helpful for evaluating the efficacy of treatment, and the correlation of these two parameters with the OSDI score may increase the objectivity while questioning the

  7. IMPACT STUDY OF ANISOTROPIC OPTICAL FIBERS WINDING WITH DIFFERENT TENSION VALUE ON THE H-PARAMETER INVARIANCE DEGREE

    Directory of Open Access Journals (Sweden)

    A. B. Mukhtubayev

    2015-09-01

    Full Text Available Subject of Research. We have investigated the effect of anisotropic optical fibers winding with an elliptical sheath subjecting to stress on the H-parameter invariance degree. This type of optical fiber is used in the manufacture of fiber loop in fiber-optic gyroscopes. Method of Research. The method of research is based on the application of Michelson polarization scanning interferometer as a measuring device. Superluminescent diode with a central wavelength of 1575 nm and a half-width of the spectrum equal to 45 nm is used as a radiation source. The studies were carried out with anisotropic optical fiber with 50 m long elliptical sheath subjecting to stress. The fiber was wound with one layer turn to turn on the coil with a diameter of 18 cm, which is used in the design of fiber-optic gyroscope. The tension force of the optical fiber was controlled during winding on a special machine. Main Results. It was found that at the increase of tension force from 0.05 N to 0.8 H the value of H-parameter increases from 7×10-6 1/m up to 178×10-6 1/m, respectively; i.e. the coupling coefficient of orthogonal modes in the test fiber is being increased. Thus, it is necessary to consider the longitudinal tension force of fiber in the design and manufacture of the fiber-optic sensors of high accuracy class: the less the fiber winding power, the higher invariance degree of distributed H-parameter. The longitudinal tension force of anisotropic optical fiber with elliptical sheath subjecting to stress equal to 0.2 N is recommended in the process of designing fiber-optic gyroscopes. Practical Relevance. The proposed method of Michelson scanning interferometer is usable in the production process for quality determination of the optical fiber winding: no local defects, value controlling of fiber H-parameter.

  8. Phase-only SLM Generating Variable Patterns Applied in Optical Connection

    International Nuclear Information System (INIS)

    Liu, B H; Wu, L Y; Zhang, J

    2006-01-01

    An adaptive optical communication system is proposed. The system sends spatial information by emitting multiple variable laser beams generated from a programmable diffractive optical element (DOE): phase-only liquid crystal Spatial Light Modulator (SLM). Laser beams carrying signals are programmable by an optimal algorithm based on an iterative Fourier transformation algorithm. The system has the advantage in redundancy of signal by the means of broadcast. It can adaptively seek position and transmit information in parallel

  9. Nanoengineered optical urea biosensor for estimating hemodialysis parameters in spent dialysate.

    Science.gov (United States)

    Swati, M; Hase, N K; Srivastava, Rohit

    2010-08-31

    An optical biosensing scheme based on urease encapsulated calcium alginate microspheres which are coated with polyelectrolyte nanofilms predominantly composed of cresol red (CR) dye is demonstrated in this paper. The dye molecules within the nanofilms are deposited via the layer-by-layer (LbL) self-assembly technique on the microspheres and used as the optical transducer. A flow through cell constructed using a cuvette attached to a fiber optic spectrometer was used to determine the response of the biosensor to standard urea solutions of different concentrations. The change in pH and the absorbance ratio was monitored with time and these results were used for measurements of urea concentrations in the spent dialysate fluid. The biological parameters controlling hemodialysis such as dialyzer clearance or Kt/V and percent removed urea (PRU) have also been reported. The results demonstrate that the urea biosensor is pH reversible with a sensitivity of 0.09 pH units/min and is able to detect a change of 0.005 ratio units in urea concentration ranging 0.1-60 mg dL(-1). The response time of the sensor was calculated as 8 min while the detection range of urea covered the levels that are present in the spent dialysate fluid. The results obtained in the analysis of biological samples were in good agreement with those obtained by a reference method, showing no significant differences at a confidence level of 95%. 2010 Elsevier B.V. All rights reserved.

  10. Effect of fabrication parameters on morphological and optical properties of highly doped p-porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Maryam, E-mail: mar.zare@gmail.com [Young Researchers Club, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr (Iran, Islamic Republic of); Shokrollahi, Abbas [Young Researchers Club, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr (Iran, Islamic Republic of); Seraji, Faramarz E. [Optical Communication Group, Iran Telecom Research Center, Tehran (Iran, Islamic Republic of)

    2011-09-01

    Porous silicon (PS) layers were fabricated by anodization of low resistive (highly doped) p-type silicon in HF/ethanol solution, by varying current density, etching time and HF concentration. Atomic force microscopy (AFM) and field emission scanning electron microscope (FESEM) analyses were used to investigate the physical properties and reflection spectrum was used to investigate the optical behavior of PS layers in different fabrication conditions. Vertically aligned mesoporous morphology is observed in fabricated films and with HF concentration higher than 20%. The dependence of porosity, layer thickness and rms roughness of the PS layer on current density, etching time and composition of electrolyte is also observed in obtained results. Correlation between reflectivity and fabrication parameters was also explored. Thermal oxidation was performed on some mesoporous layers that resulted in changes of surface roughness, mean height and reflectivity of the layers.

  11. Evaluation of third order nonlinear optical parameters of CdS/PVA nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Mamta [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160014 (India); Department of Applied Sciences (Physics), UIET, Panjab University, Chandigarh-160014 (India); Tripathi, S. K., E-mail: surya@pu.ac.in, E-mail: surya-tr@yahoo.com [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160014 (India)

    2015-06-24

    CdS nanoparticles dispersed in PVA are prepared by Chemical method at room temperature. The nonlinear optical parameters such as nonlinear absorption (β), nonlinear refractive index (n{sub 2}) and nonlinear susceptibility (χ{sup 3}) are calculated for this sample by using Z-scan technique. CdS/PVA samples show the two photon absorption mechanism. The third order nonlinear susceptibility is calculated from n{sub 2} and β and is found to be of the order of 10{sup −7} – 10{sup −8} m{sup 2}/V{sup 2}. The larger value of third order nonlinear susceptibility is due to dielectric and quantum confinement effect.

  12. Fluctuations of sediments-related optical parameters on a megatidal beach in the Eastern English Channel

    Science.gov (United States)

    Xing, Q.; Schmitt, F.; Loisel, H.

    2009-04-01

    To investigate the influence of turbulence coupled with waves and tides on the re-suspension of sediments, a 4-hour field experiment was conducted on a surf-zone beach near Wimereux, France where is at the Eastern English Channel and characterized by a semi-diurnal megatide (spring tidal range > 8 m). A sensor cluster was fixed 1.5 m above the sea bed when the tidal level was low. The parameters of the particle scattering coefficient and the optical attenuation coefficient were measured as a surrogate of the suspended sediments concentration (SSC), and the water temperature, the pressure, the horizontal 2-D velocity and so on, were also simultaneously measured in a continuous mode at a frequency of 1 Hz. The parameter of pressure was used for monitoring the water level and estimating the variation of surface wave heights by removing the local averages of time series, and the pressure time series show that the experiment started with a water level of about 3.7 m at 10 o'clock and ended with 4.5 m at 14 o'clock, and that the water level reached the highest at about 12 o'clock. The time series of current direction indicate that there was a steady along-coast current with a direction of 218 degrees when the water level almost reached the largest of 6 m, i.e., when the sensors were 4.5 m under the water surface. The particle scattering coefficient and the optical attenuation coefficient exhibit a similar fluctuating trend with a correlation coefficient of 0.85 between them. Although there is a time lag of about 1000 s, a relation between the optical parameters and the square of U is observed, i.e., SSC is a function of U, where U is the vector product of the along-shore and cross-shore velocities (v and u). The cross-shore velocity u fluctuates roughly with a mean of zero, and its variation decreases exponentially with the increase of water level, which is consistent with the common sense that wave orbital motions decrease exponentially with the water depth; the

  13. Size dependent diffusive parameters and tensorial diffusion equations in neutronic models for optically small nuclear systems

    International Nuclear Information System (INIS)

    Premuda, F.

    1983-01-01

    Two lines in improved neutron diffusion theory extending the efficiency of finite-difference diffusion codes to the field of optically small systems, are here reviewed. The firs involves the nodal solution for tensorial diffusion equation in slab geometry and tensorial formulation in parallelepiped and cylindrical gemometry; the dependence of critical eigenvalue from small slab thicknesses is also analitically investigated and finally a regularized tensorial diffusion equation is derived for slab. The other line refer to diffusion models formally unchanged with respect to the classical one, but where new size-dependent RTGB definitions for diffusion parameters are adopted, requiring that they allow to reproduce, in diffusion approach, the terms of neutron transport global balance; the trascendental equation for the buckling, arising in slab, sphere and parallelepiped geometry from the above requirement, are reported and the sizedependence of the new diffusion coefficient and extrapolated end point is investigated

  14. The Diagnosis of Plasma Parameters in Surface Alloying Technique by Optical Emission Spectrometry

    International Nuclear Information System (INIS)

    Fu Yabo; Zhang Yuefei; Chen Qiang; Zhang Guangqiu; Gao Yuan; Wang Jianzhong; Kui Xiaoyun

    2006-01-01

    Electron density (Ne) in a glow discharge plasma for the surface alloying technique is diagnosed by optical emission spectrometry (OES). With CH 4 as the feeding gas, Ne is obtained by comparing the Hβ spectrum according to the Stark broadening effect. It is noticed that Ne varies with the working pressures (30 Pa to 70 Pa) and cathode voltages (500 V to 1000 V), respectively. Due to an abnormal glow discharge, Ne is between 1.71x10 15 /cm 3 to 6.64x10 15 /cm 3 and increases rapidly with working gas pressures and cathode voltages. The results show that OES is a useful method to measure the plasma parameters in a surface alloying glow discharge plasma

  15. Parameters affecting temporal resolution of Time Resolved Integrative Optical Neutron Detector (TRION)

    International Nuclear Information System (INIS)

    Mor, I; Vartsky, D; Bar, D; Feldman, G; Goldberg, M B; Brandis, M; Dangendorf, V; Tittelmeier, K; Bromberger, B; Weierganz, M

    2013-01-01

    The Time-Resolved Integrative Optical Neutron (TRION) detector was developed for Fast Neutron Resonance Radiography (FNRR), a fast-neutron transmission imaging method that exploits characteristic energy-variations of the total scattering cross-section in the E n = 1–10 MeV range to detect specific elements within a radiographed object. As opposed to classical event-counting time of flight (ECTOF), it integrates the detector signal during a well-defined neutron Time of Flight window corresponding to a pre-selected energy bin, e.g., the energy-interval spanning a cross-section resonance of an element such as C, O and N. The integrative characteristic of the detector permits loss-free operation at very intense, pulsed neutron fluxes, at a cost however, of recorded temporal resolution degradation This work presents a theoretical and experimental evaluation of detector related parameters which affect temporal resolution of the TRION system

  16. The limits of the electron optical parameters of asymmetric double pipecol magnetic objective lenses

    International Nuclear Information System (INIS)

    Al-khashab, A. M.; Abas, K. A.

    1997-01-01

    The asymmetrical magnetic electron lens is of great importance for the electron microscopes intended for high resolution. Such lenses are determined not only by its geometric structure and shape parameters but also by the gap width to bore diameter (S/D) of its pole pieces. a systematic investigation has been carried out for asymmetric objective lenses having different bore diameters. The results indicate that the op per h ore diameter of pole piece lens has considerable effects on the electron optical properties. The Comparison between the two sets of the family of asymmetric lenses provides good performance, and suggests that the ratio of the lens gap width to the bore diameters of its pole pieces (S/ D 1 /D 2 =3) are favourable. (authors). 9 refs., 9 figs

  17. Research on the critical parameters initialization of optical PMD compensator in high bit-rate systems

    Science.gov (United States)

    Zhao, Wenyu; Zhang, Haiyi; Ji, Yuefeng; Xu, Daxiong

    2004-05-01

    Based on the proposed polarization mode dispersion (PMD) compensation simulation model and statistical analysis method (Monte-Carlo), the critical parameters initialization of two typical optical domain PMD compensators, which include optical PMD method with fixed compensation differential group delay (DGD) and that with variable compensation DGD, are detailedly investigated by numerical method. In the simulation, the line PMD values are chosen as 3ps, 4ps and 5ps and run samples are set to 1000 in order to achieve statistical evaluation for PMD compensated systems, respectively. The simulation results show that for the PMD value pre-known systems, the value of the fixed DGD compensator should be set to 1.5~1.6 times of line PMD value in order to reach the optimum performance, but for the second kind of PMD compensator, the DGD range of lower limit should be 1.5~1.6 times of line PMD provided that of upper limit is set to 3 times of line PMD, if no effective ways are chosen to resolve the problem of local minimum in optimum process. Another conclusion can be drawn from the simulation is that, although the second PMD compensator holds higher PMD compensation performance, it will spend more feedback loops to look up the optimum DGD value in the real PMD compensation realization, and this will bring more requirements on adjustable DGD device, not only wider adjustable range, but rapid adjusting speed for real time PMD equalization.

  18. Gate-tunable gigantic changes in lattice parameters and optical properties in VO2

    Science.gov (United States)

    Nakano, Masaki; Okuyama, Daisuke; Shibuya, Keisuke; Ogawa, Naoki; Hatano, Takafumi; Kawasaki, Masashi; Arima, Taka-Hisa; Iwasa, Yoshihiro; Tokura, Yoshinori

    2014-03-01

    The field-effect transistor provides an electrical switching function of current flowing through a channel surface by external gate voltage (VG). We recently reported that an electric-double-layer transistor (EDLT) based on vanadium dioxide (VO2) enables electrical switching of the metal-insulator phase transition, where the low-temperature insulating state can be completely switched to the metallic state by application of VG. Here we demonstrate that VO2-EDLT enables electrical switching of lattice parameters and optical properties as well as electrical current. We performed in-situ x-ray diffraction and optical transmission spectroscopy measurements, and found that the c-axis length and the infrared transmittance of VO2 can be significantly modulated by more than 1% and 40%, respectively, by application of VG. We emphasize that these distinguished features originate from the electric-field induced bulk phase transition available with VO2-EDLT. This work was supported by the Japan Society for the Promotion of Science (JSPS) through its ``Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).''

  19. Production of aerosols by optical catapulting: Imaging, performance parameters and laser-induced plasma sampling rate

    International Nuclear Information System (INIS)

    Abdelhamid, M.; Fortes, F.J.; Fernández-Bravo, A.; Harith, M.A.; Laserna, J.J.

    2013-01-01

    Optical catapulting (OC) is a sampling and manipulation method that has been extensively studied in applications ranging from single cells in heterogeneous tissue samples to analysis of explosive residues in human fingerprints. Specifically, analysis of the catapulted material by means of laser-induced breakdown spectroscopy (LIBS) offers a promising approach for the inspection of solid particulate matter. In this work, we focus our attention in the experimental parameters to be optimized for a proper aerosol generation while increasing the particle density in the focal region sampled by LIBS. For this purpose we use shadowgraphy visualization as a diagnostic tool. Shadowgraphic images were acquired for studying the evolution and dynamics of solid aerosols produced by OC. Aluminum silicate particles (0.2–8 μm) were ejected from the substrate using a Q-switched Nd:YAG laser at 1064 nm, while time-resolved images recorded the propagation of the generated aerosol. For LIBS analysis and shadowgraphy visualization, a Q-switched Nd:YAG laser at 1064 nm and 532 nm was employed, respectively. Several parameters such as the time delay between pulses and the effect of laser fluence on the aerosol production have been also investigated. After optimization, the particle density in the sampling focal volume increases while improving the aerosol sampling rate till ca. 90%. - Highlights: • Aerosol generation by optical catapulting has been successfully optimized. • We study the evolution and dynamics of solid aerosols produced by OC. • We use shadowgraphy visualization as a diagnostic tool. • Effects of temporal conditions and laser fluence on the elevation of the aerosol cloud have been investigated. • The observed LIBS sampling rate increased from 50% reported before to approximately 90%

  20. Descriptive parameters of the erythrocyte aggregation phenomenon using a laser transmission optical chip

    Science.gov (United States)

    Toderi, Martín A.; Castellini, Horacio V.; Riquelme, Bibiana D.

    2017-01-01

    The study of red blood cell (RBC) aggregation is of great interest because of its implications for human health. Altered RBC aggregation can lead to microcirculatory problems as in vascular pathologies, such as hypertension and diabetes, due to a decrease in the erythrocyte surface electric charge and an increase in the ligands present in plasma. The process of erythrocyte aggregation was studied in stasis situation (free shear stresses), using an optical chip based on the laser transmission technique. Kinetic curves of erythrocyte aggregation under different conditions were obtained, allowing evaluation and characterization of this process. Two main characteristics of blood that influence erythrocyte aggregation were analyzed: the erythrocyte surface anionic charge (EAC) after digestion with the enzyme trypsin and plasmatic protein concentration in suspension medium using plasma dissolutions in physiological saline with human albumin. A theoretical approach was evaluated to obtain aggregation and disaggregation ratios by syllectograms data fitting. Sensible parameters (Amp100, t) regarding a reduced erythrocyte EAC were determined, and other parameters (AI, M-Index) resulted that are representative of a variation in the plasmatic protein content of the suspension medium. These results are very useful for further applications in biomedicine.

  1. Afferent and Efferent Connections of the Optic Tectum in the Carp (Cyprinus carpio L.)

    NARCIS (Netherlands)

    Luiten, P.G.M.

    1981-01-01

    The afferent and efferent connections of the tectum opticum in the carp (Cyprinus carpio L.) were studied with the HRP method. Following iontophoretic peroxidase injections in several parts of the rectum anterograde transport of the enzyme revealed tectal projections to the lateral geniculate

  2. Demonstration of the frequency modulation of optical signals with a high frequency deviation parameter

    International Nuclear Information System (INIS)

    Shamray, A V; Kozlov, A S; Il'ichev, I V; Petrov, M P

    2008-01-01

    A new type of an integrated optical modulator for the frequency coding of optical signals is developed and fabricated. The modulator operation is based on the original technology of the electric control of a Bragg grating. The frequency modulation of an optical signal with the frequency deviation of 25 GHz is demonstrated experimentally. The modular was used to transfer the ASCII code through an optical fibre. (optical communication)

  3. WDM cross-connect cascade based on all-optical wavelength converters for routing and wavelength slot interchanging using a reduced number of internal wavelengths

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Mikkelsen, Benny; Jørgensen, Bo Foged

    1998-01-01

    interchanging can be used to create a robust and nonblocking OXC. However, for an OXC with n fiber inlets each carrying m wavelengths the OXC requires n×m internal wavelengths, which constrains the size of the cross-connect. In this paper we therefore propose and demonstrate an architecture that uses a reduced......Optical transport layers need rearrangeable wavelength-division multiplexing optical cross-connects (OXCs) to increase the capacity and flexibility of the network. It has previously been shown that a cross-connect based on all-optical wavelength converters for routing as well as wavelength slot...... set of internal wavelengths without sacrificing cross-connecting capabilities. By inserting a partly equipped OXC with the new architecture in a 10-Gbit/s re-circulating loop setup we demonstrate the possibility of cascading up to ten OXCs. Furthermore, we investigate the regenerating effect...

  4. A wideband connection to sperm whales: A fiber-optic, deep-sea hydrophone array

    DEFF Research Database (Denmark)

    Heerfordt, Anders; Møhl, Bertel; Wahlberg, Magnus

    2007-01-01

    A 10-element, 950 m long, vertical hydrophone array based on fiber-optic data transmission has been developed primarily for studying the beam pattern from deep diving cetaceans emitting sonar pulses. The array elements have a configurable sampling rate and resolution with a maximum signal bandwidth...

  5. Spatial light modulators for full cross-connections in optical networks

    Science.gov (United States)

    Juday, Richard D. (Inventor)

    2004-01-01

    A polarization-independent optical switch is disclosed for switching at least one incoming beam from at least one input source to at least one output drain. The switch includes a polarizing beam splitter to split each of the at least one incoming beam into a first input beam and a second input beam, wherein the first input beam and the second input beams are independently polarized; a wave plate optically coupled to the second input beam for converting the polarization of the second input beam to an appropriately polarized second input beam; a beam combiner optically coupled to the first input beam and the modified second input beam, wherein the beam combiner accepts the first input beam and the modified second input beam to produce a combined beam; the combined beam is invariant to the polarization state of the input source's polarization; and a controllable spatial light modulator optically coupled to the combined beam, wherein the combined beam is diffracted by the controllable spatial light modulator to place light at a plurality of output locations.

  6. Dependences of optical properties of spherical two-layered nanoparticles on parameters of gold core and material shell

    International Nuclear Information System (INIS)

    Pustovalov, V.K.; Astafyeva, L.G.; Zharov, V.P.

    2013-01-01

    Modeling of nonlinear dependences of optical properties of spherical two-layered gold core and some material shell nanoparticles (NPs) placed in water on parameters of core and shell was carried out on the basis of the extended Mie theory. Efficiency cross-sections of absorption, scattering and extinction of radiation with wavelength 532 nm by core–shell NPs in the ranges of core radii r 00 =5–40 nm and of relative NP radii r 1 /r 00 =1–8 were calculated (r 1 —radius of two-layered nanoparticle). Shell materials were used with optical indexes in the ranges of refraction n 1 =0.2–1.5 and absorption k 1 =0–3.5 for the presentation of optical properties of wide classes of shell materials (including dielectrics, metals, polymers, vapor shell around gold core). Results show nonlinear dependences of optical properties of two-layered NPs on optical indexes of shell material, core r 00 and relative NP r 1 /r 00 radii. Regions with sharp decrease and increase of absorption, scattering and extinction efficiency cross-sections with changing of core and shell parameters were investigated. These dependences should be taken into account for applications of two-layered NPs in laser nanomedicine and optical diagnostics of tissues. The results can be used for experimental investigation of shell formation on NP core and optical determination of geometrical parameters of core and shell of two-layered NPs. -- Highlights: • Absorption, scattering and extinction of two-layered nanoparticles are studied. • Shell materials change in wide regions of materials (metals, dielectrics, vapor). • Effect of sharp decrease and increase of optical characteristics is established. • Explanation of sharp decreasing and increasing optical characteristics is presented

  7. All-optical functional synaptic connectivity mapping in acute brain slices using the calcium integrator CaMPARI.

    Science.gov (United States)

    Zolnik, Timothy A; Sha, Fern; Johenning, Friedrich W; Schreiter, Eric R; Looger, Loren L; Larkum, Matthew E; Sachdev, Robert N S

    2017-03-01

    The genetically encoded fluorescent calcium integrator calcium-modulated photoactivatable ratiobetric integrator (CaMPARI) reports calcium influx induced by synaptic and neural activity. Its fluorescence is converted from green to red in the presence of violet light and calcium. The rate of conversion - the sensitivity to activity - is tunable and depends on the intensity of violet light. Synaptic activity and action potentials can independently initiate significant CaMPARI conversion. The level of conversion by subthreshold synaptic inputs is correlated to the strength of input, enabling optical readout of relative synaptic strength. When combined with optogenetic activation of defined presynaptic neurons, CaMPARI provides an all-optical method to map synaptic connectivity. The calcium-modulated photoactivatable ratiometric integrator (CaMPARI) is a genetically encoded calcium integrator that facilitates the study of neural circuits by permanently marking cells active during user-specified temporal windows. Permanent marking enables measurement of signals from large swathes of tissue and easy correlation of activity with other structural or functional labels. One potential application of CaMPARI is labelling neurons postsynaptic to specific populations targeted for optogenetic stimulation, giving rise to all-optical functional connectivity mapping. Here, we characterized the response of CaMPARI to several common types of neuronal calcium signals in mouse acute cortical brain slices. Our experiments show that CaMPARI is effectively converted by both action potentials and subthreshold synaptic inputs, and that conversion level is correlated to synaptic strength. Importantly, we found that conversion rate can be tuned: it is linearly related to light intensity. At low photoconversion light levels CaMPARI offers a wide dynamic range due to slower conversion rate; at high light levels conversion is more rapid and more sensitive to activity. Finally, we employed Ca

  8. The need for a single cleaning standard for OEM and OSP fiber optic connections

    Science.gov (United States)

    Forrest, Edward J., Jr.; Blair, Paul

    2009-01-01

    Development of fiber optic communications networks has continued in virtually all geographies of the world. Some calculate that expansion in the USA alone will continue to 2025. After that time there will maintenance, upgrade, and replacement. While some nations are more advanced than others and some enterprises more sophisticated than others, the undeniable reality is that previous networks will, in some fashion or another, include fiber optics. The future need is for speed and reliable bandwidth: lots of it. Decisions will be made based on new concepts that will enable far more data at far faster rates than once considered feasible or necessary. As the consumer enters the market with newly engineered home entertainment systems, additional burdens will be placed on both OEM and OSP. These are not negative challenges, but rather indicators of a new generation of consumers with awareness and demand far more advanced any may have imagined just a few years ago.

  9. Scanning near-field optical microscopy and near-field optical probes: properties, fabrication, and control of parameters

    International Nuclear Information System (INIS)

    Dryakhlushin, V F; Veiko, V P; Voznesenskii, N B

    2007-01-01

    A brief review of modern applications of scanning near-field optical (SNO) devices in microscopy, spectroscopy, and lithography is presented in the introduction. The problem of the development of SNO probes, as the most important elements of SNO devices determining their resolution and efficiency, is discussed. Based on the works of the authors, two different methods for fabricating SNO probes by using the adiabatic tapering of an optical fibre are considered: the laser-heated mechanical drawing and chemical etching. A nondestructive optical method for controlling the nanometre aperture of SNO probes is proposed, substantiated, and tested experimentally. The method is based on the reconstruction of a near-field source with the help of a theoretical algorithm of the inverse problem from the experimental far-filed intensity distribution. Some prospects for a further refinement of the construction and technology of SNO probes are discussed. (optical microscopy)

  10. An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments

    DEFF Research Database (Denmark)

    Tosello, Guido; Haitjema, H.; Leach, R.K.

    2016-01-01

    An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent...

  11. Vectorization of optically sectioned brain microvasculature: learning aids completion of vascular graphs by connecting gaps and deleting open-ended segments.

    Science.gov (United States)

    Kaufhold, John P; Tsai, Philbert S; Blinder, Pablo; Kleinfeld, David

    2012-08-01

    A graph of tissue vasculature is an essential requirement to model the exchange of gasses and nutriments between the blood and cells in the brain. Such a graph is derived from a vectorized representation of anatomical data, provides a map of all vessels as vertices and segments, and may include the location of nonvascular components, such as neuronal and glial somata. Yet vectorized data sets typically contain erroneous gaps, spurious endpoints, and spuriously merged strands. Current methods to correct such defects only address the issue of connecting gaps and further require manual tuning of parameters in a high dimensional algorithm. To address these shortcomings, we introduce a supervised machine learning method that (1) connects vessel gaps by "learned threshold relaxation"; (2) removes spurious segments by "learning to eliminate deletion candidate strands"; and (3) enforces consistency in the joint space of learned vascular graph corrections through "consistency learning." Human operators are only required to label individual objects they recognize in a training set and are not burdened with tuning parameters. The supervised learning procedure examines the geometry and topology of features in the neighborhood of each vessel segment under consideration. We demonstrate the effectiveness of these methods on four sets of microvascular data, each with >800(3) voxels, obtained with all optical histology of mouse tissue and vectorization by state-of-the-art techniques in image segmentation. Through statistically validated sampling and analysis in terms of precision recall curves, we find that learning with bagged boosted decision trees reduces equal-error error rates for threshold relaxation by 5-21% and strand elimination performance by 18-57%. We benchmark generalization performance across datasets; while improvements vary between data sets, learning always leads to a useful reduction in error rates. Overall, learning is shown to more than halve the total error

  12. Electronic polarizability, optical basicity and interaction parameter for Nd2O3 doped lithium-zinc-phosphate glasses

    Science.gov (United States)

    Algradee, M. A.; Sultan, M.; Samir, O. M.; Alwany, A. Elwhab B.

    2017-08-01

    The Nd3+-doped lithium-zinc-phosphate glasses were prepared by means of conventional melt quenching method. X-ray diffraction results confirmed the glassy nature of the studied glasses. The physical parameters such as the density, molar volume, ion concentration, polaron radius, inter-ionic distance, field strength and oxygen packing density were calculated using different formulae. The transmittance and reflectance spectra of glasses were recorded in the wavelength range 190-1200 nm. The values of optical band gap and Urbach energy were determined based on Mott-Davis model. The refractive indices for the studied glasses were evaluated from optical band gap values using different methods. The average electronic polarizability of the oxide ions, optical basicity and an interaction parameter were investigated from the calculated values of the refractive index and the optical band gap for the studied glasses. The variations in the different physical and optical properties of glasses with Nd2O3 content were discussed in terms of different parameters such as non-bridging oxygen and different concentrations of Nd cation in glass system.

  13. Network connectivity enhancement by exploiting all optical multicast in semiconductor ring laser

    Science.gov (United States)

    Siraj, M.; Memon, M. I.; Shoaib, M.; Alshebeili, S.

    2015-03-01

    The use of smart phone and tablet applications will provide the troops for executing, controlling and analyzing sophisticated operations with the commanders providing crucial documents directly to troops wherever and whenever needed. Wireless mesh networks (WMNs) is a cutting edge networking technology which is capable of supporting Joint Tactical radio System (JTRS).WMNs are capable of providing the much needed bandwidth for applications like hand held radios and communication for airborne and ground vehicles. Routing management tasks can be efficiently handled through WMNs through a central command control center. As the spectrum space is congested, cognitive radios are a much welcome technology that will provide much needed bandwidth. They can self-configure themselves, can adapt themselves to the user requirement, provide dynamic spectrum access for minimizing interference and also deliver optimal power output. Sometimes in the indoor environment, there are poor signal issues and reduced coverage. In this paper, a solution utilizing (CR WMNs) over optical network is presented by creating nanocells (PCs) inside the indoor environment. The phenomenon of four-wave mixing (FWM) is exploited to generate all-optical multicast using semiconductor ring laser (SRL). As a result same signal is transmitted at different wavelengths. Every PC is assigned a unique wavelength. By using CR technology in conjunction with PC will not only solve network coverage issue but will provide a good bandwidth to the secondary users.

  14. Investigation on influence parameters in measurements of the optomechanical hole plate using an optical coordinate measuring machine

    DEFF Research Database (Denmark)

    Morace, Renate Erica; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2003-01-01

    This paper describes the results of an experimental investigation on influence parameters in optical coordinate measurements of the optomechanical hole plate. Special attention was paid to the background of the object, which strongly influences the measurement result. Furthermore, it is seen that...... influences, the measurements were all performed with no movements of the axes of the CMM....

  15. Characterization of sub-channel based Málaga atmospheric optical links with real β  parameter

    DEFF Research Database (Denmark)

    López-González, Francisco Javier; Jurado-Navas, Antonio; Garrido-Balsells, José María

    2017-01-01

    A generalization of the Málaga atmospheric optical communications links treated as a finite number of generalized-K distributed sub-channels is analyzed in terms of outage probability and outage rate when its β parameter belongs to the set of real numbers. To the best of the author's knowledge, ...

  16. Thermo-optically tuned photonic resonators with concurrent electrical connection and thermal isolation

    Science.gov (United States)

    Lentine, Anthony L.; Kekatpure, Rohan Deodatta; Zortman, William A.; Savignon, Daniel J.

    2016-06-14

    A photonic resonator system is designed to use thermal tuning to adjust the resonant wavelength of each resonator in the system, with a separate tuning circuit associated with each resonator so that individual adjustments may be made. The common electrical ground connection between the tuning circuits is particularly formed to provide thermal isolation between adjacent resonators by including a capacitor along each return path to ground, where the presence of the capacitor's dielectric material provides the thermal isolation. The use of capacitively coupling necessarily requires the use of an AC current as an input to the heater element (conductor/resistor) of each resonator, where the RMS value of the AC signal is indicative of the amount of heat that is generated along the element and the degree of wavelength tuning that is obtained.

  17. Connections between physical, optical and biogeochemical processes in the Pacific Ocean

    Science.gov (United States)

    Xiu, Peng; Chai, Fei

    2014-03-01

    A new biogeochemical model has been developed and coupled to a three-dimensional physical model in the Pacific Ocean. With the explicitly represented dissolved organic pools, this new model is able to link key biogeochemical processes with optical processes. Model validation against satellite and in situ data indicates the model is robust in reproducing general biogeochemical and optical features. Colored dissolved organic matter (CDOM) has been suggested to play an important role in regulating underwater light field. With the coupled model, physical and biological regulations of CDOM in the euphotic zone are analyzed. Model results indicate seasonal variability of CDOM is mostly determined by biological processes, while the importance of physical regulation manifests in the annual mean terms. Without CDOM attenuating light, modeled depth-integrated primary production is about 10% higher than the control run when averaged over the entire basin, while this discrepancy is highly variable in space with magnitudes reaching higher than 100% in some locations. With CDOM dynamics integrated in physical-biological interactions, a new mechanism by which physical processes affect biological processes is suggested, namely, physical transport of CDOM changes water optical properties, which can further modify underwater light field and subsequently affect the distribution of phytoplankton chlorophyll. This mechanism tends to occur in the entire Pacific basin but with strong spatial variability, implying the importance of including optical processes in the coupled physical-biogeochemical model. If ammonium uptake is sufficient to permit utilization of DOM, that is, UB∗⩾-U{U}/{U}-{(1-r_b)}/{RB}, then bacteria uptake of DOM has the form of FB=(1-r_b){U}/{RB}, bacteria respiration, SB=r_b×U, remineralization by bacteria, EB=UC{UN}/{UC}-{(1-r_b)}/{RB}. If EB > 0, then UB = 0; otherwise, UB = -EB. If there is insufficient ammonium, that is, UB∗CO2 is calculated using the

  18. Connecting optical and X-ray tracers of galaxy cluster relaxation

    Science.gov (United States)

    Roberts, Ian D.; Parker, Laura C.; Hlavacek-Larrondo, Julie

    2018-04-01

    Substantial effort has been devoted in determining the ideal proxy for quantifying the morphology of the hot intracluster medium in clusters of galaxies. These proxies, based on X-ray emission, typically require expensive, high-quality X-ray observations making them difficult to apply to large surveys of groups and clusters. Here, we compare optical relaxation proxies with X-ray asymmetries and centroid shifts for a sample of Sloan Digital Sky Survey clusters with high-quality, archival X-ray data from Chandra and XMM-Newton. The three optical relaxation measures considered are the shape of the member-galaxy projected velocity distribution - measured by the Anderson-Darling (AD) statistic, the stellar mass gap between the most-massive and second-most-massive cluster galaxy, and the offset between the most-massive galaxy (MMG) position and the luminosity-weighted cluster centre. The AD statistic and stellar mass gap correlate significantly with X-ray relaxation proxies, with the AD statistic being the stronger correlator. Conversely, we find no evidence for a correlation between X-ray asymmetry or centroid shift and the MMG offset. High-mass clusters (Mhalo > 1014.5 M⊙) in this sample have X-ray asymmetries, centroid shifts, and Anderson-Darling statistics which are systematically larger than for low-mass systems. Finally, considering the dichotomy of Gaussian and non-Gaussian clusters (measured by the AD test), we show that the probability of being a non-Gaussian cluster correlates significantly with X-ray asymmetry but only shows a marginal correlation with centroid shift. These results confirm the shape of the radial velocity distribution as a useful proxy for cluster relaxation, which can then be applied to large redshift surveys lacking extensive X-ray coverage.

  19. Channel optical waveguides in various silicate glasses - optimalization of their parameters

    Czech Academy of Sciences Publication Activity Database

    Salavcová, Linda; Ondráček, František; Špirková, J.; Míka, M.

    2007-01-01

    Roč. 18, Suppl. 1 (2007), S371-S373 ISSN 0957-4522. [ICOOPMA2006 - International Conference on Optical and Optoelectronic Properties of Materials and Applications /1./. Darwin, 15.07.2006-22.07.2006] R&D Projects: GA ČR(CZ) GA106/05/0706 Institutional research plan: CEZ:AV0Z20670512 Keywords : ion exchange * optical waveguides * optical measurement Subject RIV: JA - Electronics ; Optoelectronic s, Electrical Engineering Impact factor: 0.947, year: 2007

  20. Application of complex geometrical optics to determination of thermal, transport, and optical parameters of thin films by the photothermal beam deflection technique.

    Science.gov (United States)

    Korte, Dorota; Franko, Mladen

    2015-01-01

    In this work, complex geometrical optics is, for what we believe is the first time, applied instead of geometrical or wave optics to describe the probe beam interaction with the field of the thermal wave in photothermal beam deflection (photothermal deflection spectroscopy) experiments on thin films. On the basis of this approach the thermal (thermal diffusivity and conductivity), optical (energy band gap), and transport (carrier lifetime) parameters of the semiconductor thin films (pure TiO2, N- and C-doped TiO2, or TiO2/SiO2 composites deposited on a glass or aluminum support) were determined with better accuracy and simultaneously during one measurement. The results are in good agreement with results obtained by the use of other methods and reported in the literature.

  1. Deformation of the Early Glaucomatous Monkey Optic Nerve Head Connective Tissue after Acute IOP Elevation in 3-D Histomorphometric Reconstructions

    Science.gov (United States)

    Yang, Hongli; Thompson, Hilary; Roberts, Michael D.; Sigal, Ian A.; Downs, J. Crawford

    2011-01-01

    Purpose. To retest the hypothesis that monkey ONH connective tissues become hypercompliant in early experimental glaucoma (EEG), by using 3-D histomorphometric reconstructions, and to expand the characterization of EEG connective tissue deformation to nine EEG eyes. Methods. Trephinated ONH and peripapillary sclera from both eyes of nine monkeys that were perfusion fixed, with one normal eye at IOP 10 mm Hg and the other EEG eye at 10 (n = 3), 30 (n = 3), or 45 (n = 3) mm Hg were serial sectioned, 3-D reconstructed, 3-D delineated, and quantified with 3-D reconstruction techniques developed in prior studies by the authors. Overall, and for each monkey, intereye differences (EEG eye minus normal eye) for each parameter were calculated and compared by ANOVA. Hypercompliance in the EEG 30 and 45 eyes was assessed by ANOVA, and deformations in all nine EEG eyes were separately compared by region without regard for fixation IOP. Results. Hypercompliant deformation was not significant in the overall ANOVA, but was suggested in a subset of EEG 30/45 eyes. EEG eye deformations included posterior laminar deformation, neural canal expansion, lamina cribrosa thickening, and posterior (outward) bowing of the peripapillary sclera. Maximum posterior laminar deformation and scleral canal expansion co-localized to either the inferior nasal or superior temporal quadrants in the eyes with the least deformation and involved both quadrants in the eyes achieving the greatest deformation. Conclusions. The data suggest that, in monkey EEG, ONH connective tissue hypercompliance may occur only in a subset of eyes and that early ONH connective tissue deformation is maximized in the superior temporal and/or inferior nasal quadrants. PMID:20702834

  2. The influence of optical parameters on impurity determinations by IR spectroscopy

    International Nuclear Information System (INIS)

    Lombard, O.J.

    1985-01-01

    The important role of impurities in semiconductor materials is the subject of continuous research. The concentration of interstitial oxygen impurities in silicon are determined with the aid of infrared spectroscopy. The maximum absorption coefficient of the oxygen absorption peak, centered at 9,06 μm, is determined and the impurity concentration is then calculated using a calibration factor. This procedure was evaluated, paying particular attention to those optical parameters which may influence these impurity determinations. A thorough discussion of the theoretical and experimental aspects of infrared spectroscopy in general is followed by an overview of previous experimental work. This lead to some theoretical analysis regarding the influence of the index of refraction, the index of absorption and multiple reflections in the silicon wafer on impurity determinations. This lead to specific experimental investigations. The influence of the surface morphology of samples on impurity determinations was studied by determining the reflectance of silicon surfaces. It was established that the surface reflectance plays a role and that it must be taken into consideration for accurate impurity concentration determinations. The most accurate values for the absorption coefficient due to oxygen in silicon are calculated. This requires that the surface of the silicon wafers must be highly polished for the formula to be valid. Acceptable values for the absorption coefficient of damaged surfaces are obtained if the uncorrected formula is used. Experimental results may deviate as much as 32% from the real impurity concentration if the wrong formula is used to calculate the absorption coefficient of oxygen in silicon at 9,06 μm

  3. Optical mapping of prefrontal brain connectivity and activation during emotion anticipation.

    Science.gov (United States)

    Wang, Meng-Yun; Lu, Feng-Mei; Hu, Zhishan; Zhang, Juan; Yuan, Zhen

    2018-09-17

    Accumulated neuroimaging evidence shows that the dorsal lateral prefrontal cortex (dlPFC) is activated during emotion anticipation. The aim of this work is to examine the brain connectivity and activation differences in dlPFC between the positive, neutral and negative emotion anticipation by using functional near-infrared spectroscopy (fNIRS). The hemodynamic responses were first assessed for all subjects during the performance of various emotion anticipation tasks. And then small-world analysis was performed, in which the small-world network indicators including the clustering coefficient, average path length, average node degree, and measure of small-world index were calculated for the functional brain networks associated with the positive, neutral and negative emotion anticipation, respectively. We discovered that compared to negative and neutral emotion anticipation, the positive one exhibited enhanced brain activation in the left dlPFC. Although the functional brain networks for the three emotion anticipation cases manifested the small-world properties regarding the clustering coefficient, average path length, average node degree, and measure of small-world index, the positive one showed significantly higher clustering coefficient and shorter average path length than those from the neutral and negative cases. Consequently, the small-world network indicators and brain activation in dlPPC were able to distinguish well between the positive, neutral and negative emotion anticipation. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Application effect of hyperbaric oxygen in the patients with optic atrophy and influence for the hemodynamic parameters

    Directory of Open Access Journals (Sweden)

    Kun Zhang

    2015-01-01

    Full Text Available AIM: To observe the application effect of hyperbaric oxygen in the patients with optic atrophy and influence degree for the hemodynamic parameters.METHODS: Fifty patients with optic atrophy in our hospital from January 2012 to January 2014 were objected, they were randomly divided into control group(conventional optic atrophy treatment groupand observation group(conventional treatment and hyperbaric oxygen treatment group, each group was 25 cases. Statistical analysis of two group before and after treatment eyesight, vision acuity, visual field defect and ophthalmic artery, central retinal artery blood flow parameters were undergone.RESULTS: The sight, visual field sensitivity and field vision defect of observation group were all better than those of control group at first, second and third course after the treatment, arteriae ophthalmica and arteriae centralis retinae EDV and PSV were all higher than those of control group, PI and RI were all lower than those of control group were all significant differences(PCONCLUSION: The application effect of hyperbaric oxygen in the patients with optic atrophy is better, and the influence of treatment method for the ocular hemodynamic parameters are more active.

  5. Optical Lattice Bose-Einstein Condensates and the dd Fusion - Iwamura Connection

    Science.gov (United States)

    Chubb, Talbot

    2003-03-01

    My conjecture: LENR dd fusion occurs in PdDx when a subset of the interstitial deuterons occupy tetrahedral sites in a PdDx crystallite. The tetrahedral deuterons(d's), which occupy shallow potential wells, behave as a superfluid, similar to ultracold Na atoms in shallow-well optical traps, as modeled by Jaksch et al.(D. Jaksch, et al, Phys. Rev. Lett., 81, 3108 (1998).) The tetrahedral d's form a deuteron (d) subsystem, which is neutralized by an electron subsystem containing an equal number of electrons. In the superfluid all the properties of each quasiparticle d are partitioned among N_s_i_te equivalent sites. The partitioning of the d point charge reduces the Coulomb self-repulsion within each quasiparticle pair, which causes wave function overlap at large N_s_i_t_e, allowing d-d fusion. Similarly, partitioning of the point charge of each single quasiparticle d reduces the Coulomb repulsion between it and an obstructing impurity atom, which causes wave function overlap between quasiparticle and atom at large N_s_i_t_e, allowing transmutation of the impurity atom. The Iwamura reaction(Y. Iwamura, et al, Japan J. of Appl. Physics, 41A, 4642 (2002).) is 4 ^2D^+_B_l_o_ch + 4 e^-_B_l_o_ch + ^1^3^3Cs arrow ^1^4^1Pr, with the reaction energy incoherently transferred to the lattice.

  6. Determination of basic state parameters and characterization of optical, dielectric and fluorescence properties of calcium boro lactate (CaBL)

    International Nuclear Information System (INIS)

    Vijayalakshmi, A.; Balraj, V.

    2016-01-01

    This paper describes the calculation of basic solid state parameters like penn gap, plasma energy, polarizability and fermi energy for calcium boro lactate single crystal. calcium boro lactate crystals were developed by solution growth method. Single crystal diffraction studies carried out and calculated basic solid state criterion for the CaBL compound. optical nature of these compound explained by using UV-Visible spectrum. Electro-optic behaviour of the crystal explained by dielectric studies. Light emitting properties explained by fluorescence studies. (author)

  7. CHANGE OF CONNECTION BETWEEN MAGNETIC PARAMETERS OF CAST IRON IN COMPARISON WITH STEEL UNDER INFLUENCE OF INTERNAL DEMAGNETIZATION

    Directory of Open Access Journals (Sweden)

    S. G. Sandomirsky

    2014-01-01

    Full Text Available Connection of maximum magnetic permeability µm of cast irons with coercive force Нс and residual magnetism Мr is established in all size of changing of the magnetic characteristics of cast iron. Differences of this connection for steels and cast irons are revealed. Formula for calculation µm of steels by Нс and Мr is corrected for calculation µm of cast irons. As a result of correction the calculation error of cast irons µm is diminished. The results can be used in magnetic structural analysis instead of labor-consuming measurement µm.

  8. Influence of Hub Parameters on Joining Forces and Torque Transmission Output of Plastically-Joined Shaft-Hub-Connections with a Knurled Contact Surface

    Directory of Open Access Journals (Sweden)

    Lukáš Suchý

    2018-04-01

    Full Text Available A knurled interference fit is a machine part connection made by a plastic joining, which includes the advantages of commonly-used shaft-hub-connections. The combination of the friction and form fit, which are responsible for torque transmission, results in a higher power density than conventional connections. In this paper, parameter gaps are bridged with the aim of enhance the design calculation of the knurled interference fit. Experimental investigations on the shaft chamfer angle (100Cr6 and hub-diameter-ratio (AlSi1MgMn were performed. The analytical approaches are developed for calculating the joining force and maximal torque capacity by accounting for experimentally investigated loss of load transmission at high hub-diameter-ratios and high shaft chamfer angles. The presented calculation approach is an accurate tool for the assessment of early machine designs of the knurled interference fit and helps to save from having to perform time-extensive tests.

  9. Evaluation of dysthyroid optic neuropathy using T2-relaxation time of extraocular muscle as parameter

    International Nuclear Information System (INIS)

    Yu, Fumihiko; Maeda, Toshine; Inoue, Toyoko; Inoue, Yoichi

    2001-01-01

    The T2 value of magnetic resonance imaging (MRI) is useful in evaluating the activity of dysthyroid ophthlamopathy. We applied this method in evaluating dysthyroid optic neuropathy in 15 affected eyes of 15 patients. Another group of 40 eyes of 20 patients of dysthyroid opthalmopathy without hypertrophy of extraocular muscles served as control. The T2 value in dysthyroid optic neuropathy significantly decreased following treatment with corticosteroid but the value was still higher than that in control eyes. The findings show that the T2 value of MRI is useful in evaluating the therapeutic effect of dysthyroid optic neuropathy. (author)

  10. Evaluation of dysthyroid optic neuropathy using T2-relaxation time of extraocular muscle as parameter

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Fumihiko; Maeda, Toshine; Inoue, Toyoko; Inoue, Yoichi [Olympia Eye Hospital, Tokyo (Japan)

    2001-11-01

    The T2 value of magnetic resonance imaging (MRI) is useful in evaluating the activity of dysthyroid ophthlamopathy. We applied this method in evaluating dysthyroid optic neuropathy in 15 affected eyes of 15 patients. Another group of 40 eyes of 20 patients of dysthyroid opthalmopathy without hypertrophy of extraocular muscles served as control. The T2 value in dysthyroid optic neuropathy significantly decreased following treatment with corticosteroid but the value was still higher than that in control eyes. The findings show that the T2 value of MRI is useful in evaluating the therapeutic effect of dysthyroid optic neuropathy. (author)

  11. Optical photon transport in powdered-phosphor scintillators. Part II. Calculation of single-scattering transport parameters

    Energy Technology Data Exchange (ETDEWEB)

    Poludniowski, Gavin G. [Joint Department of Physics, Division of Radiotherapy and Imaging, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, United Kingdom and Centre for Vision Speech and Signal Processing (CVSSP), Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Evans, Philip M. [Centre for Vision Speech and Signal Processing (CVSSP), Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2013-04-15

    Purpose: Monte Carlo methods based on the Boltzmann transport equation (BTE) have previously been used to model light transport in powdered-phosphor scintillator screens. Physically motivated guesses or, alternatively, the complexities of Mie theory have been used by some authors to provide the necessary inputs of transport parameters. The purpose of Part II of this work is to: (i) validate predictions of modulation transform function (MTF) using the BTE and calculated values of transport parameters, against experimental data published for two Gd{sub 2}O{sub 2}S:Tb screens; (ii) investigate the impact of size-distribution and emission spectrum on Mie predictions of transport parameters; (iii) suggest simpler and novel geometrical optics-based models for these parameters and compare to the predictions of Mie theory. A computer code package called phsphr is made available that allows the MTF predictions for the screens modeled to be reproduced and novel screens to be simulated. Methods: The transport parameters of interest are the scattering efficiency (Q{sub sct}), absorption efficiency (Q{sub abs}), and the scatter anisotropy (g). Calculations of these parameters are made using the analytic method of Mie theory, for spherical grains of radii 0.1-5.0 {mu}m. The sensitivity of the transport parameters to emission wavelength is investigated using an emission spectrum representative of that of Gd{sub 2}O{sub 2}S:Tb. The impact of a grain-size distribution in the screen on the parameters is investigated using a Gaussian size-distribution ({sigma}= 1%, 5%, or 10% of mean radius). Two simple and novel alternative models to Mie theory are suggested: a geometrical optics and diffraction model (GODM) and an extension of this (GODM+). Comparisons to measured MTF are made for two commercial screens: Lanex Fast Back and Lanex Fast Front (Eastman Kodak Company, Inc.). Results: The Mie theory predictions of transport parameters were shown to be highly sensitive to both grain size

  12. Dependence of loading time on control parameters in a standard vapour—loaded magneto—optical trap

    International Nuclear Information System (INIS)

    Zhang Yi-Chi; Wu Ji-Zhou; Li Yu-Qing; Ma Jie; Wang Li-Rong; Zhao Yan-Ting; Xiao Lian-Tuan; Jia Suo-Tang

    2011-01-01

    Loading time is one of the most important dynamic characteristics of a magneto—optical trap. In this paper, we primarily report on a detailed experimental study of the effects of some magneto—optical trap control parameters on loading time, including the background vacuum pressure, the magnetic field gradient, and the intensities of trapping and repumping lasers. We compare the results with previous theoretical and experimental results, and give qualitative analysis. These experimental investigations offer some useful guidelines to control the loading time of magneto—optical traps. The controllable loading time achieved is helpful to enhance the signal-to-noise ratio of photoassociation spectroscopy, which is remarkably improved from 7 to 28.6. (atomic and molecular physics)

  13. Optical absorption and gamma-radiation-shielding parameter studies of Tm3+-doped multicomponent borosilicate glasses

    Science.gov (United States)

    Lakshminarayana, G.; Sayyed, M. I.; Baki, S. O.; Lira, A.; Dong, M. G.; Kaky, Kawa M.; Kityk, I. V.; Mahdi, M. A.

    2018-05-01

    Different concentrations (0.1‒2.0 mol%) of Tm3+-doped multicomponent borosilicate glasses with 10 mol% Li2O (alkali) or MgO (alkaline) have been synthesized and their optical absorption and radiation shielding features were studied. For both Li2O and MgO series 0.5 mol% Tm3+-doped glass samples, the evaluated Ωλ ( λ = 2, 4, and 6) Judd-Ofelt (JO) intensity parameters from experimental oscillator strengths were used in estimating the radiative transition probabilities ( A R), branching ratios ( β R), and radiative lifetimes ( τ R) for several emission transitions. Using the XCOM software, the mass attenuation coefficients ( µ/ ρ) for all the fabricated glasses were evaluated within the 0.015‒10 MeV energy range. Also, the ( µ/ ρ) values were calculated at 0.356, 0.662, 1.173, and 1.33 MeV photon energies by MCNP5 simulation code and the results were compared with those obtained by XCOM. The ( µ/ ρ) values for Li2O, as well as MgO series glasses, increase with the addition of Tm2O3 and these values for MgO series glasses are slightly higher with respect to Li2O series glasses. From the ( µ/ ρ) values, effective atomic number ( Z eff), half-value layer (HVL), and mean free path (MFP) were calculated and the HVL and MFP results revealed that high-energy photons have more penetration into a glass sample compared to low-energy photons. Further, geometric progression (GP) fitting method was utilized to calculate the exposure buildup factor (EBF) within the 0.015‒15 MeV energy range. The 2.0 mol% Tm2O3-doped glasses show a better ability to attenuate gamma-rays in comparison to other glass samples, so the addition of Tm2O3 content leads to improvement of the shielding efficiency of the prepared glasses.

  14. Two-Dimensional Optical CDMA System Parameters Limitations for Wavelength Hopping/Time-Spreading Scheme based on Simulation Experiment

    Science.gov (United States)

    Kandouci, Chahinaz; Djebbari, Ali

    2018-04-01

    A new family of two-dimensional optical hybrid code which employs zero cross-correlation (ZCC) codes, constructed by the balanced incomplete block design BIBD, as both time-spreading and wavelength hopping patterns are used in this paper. The obtained codes have both off-peak autocorrelation and cross-correlation values respectively equal to zero and unity. The work in this paper is a computer experiment performed using Optisystem 9.0 software program as a simulator to determine the wavelength hopping/time spreading (WH/TS) OCDMA system performances limitations. Five system parameters were considered in this work: the optical fiber length (transmission distance), the bitrate, the chip spacing and the transmitted power. This paper shows for what sufficient system performance parameters (BER≤10-9, Q≥6) the system can stand for.

  15. Global dependence of optical potential parameters for alpha particles with energies up to 80 MeV

    International Nuclear Information System (INIS)

    Kuterbekov, K.A.; Zholdybaev, T.K.; Sadykov, B.M.; Mukhambetzhan, A.; Kukhtina, I.N.; Penionzhkevich, Yu.Eh.

    2002-01-01

    Global (energy and mass) dependences of optical potential for α-particles with energies up to 80 MeV have been received. A Woods-Saxon form factor for macroscopic potential has been used. Energy and mass dependences of the semi-microscopic α-particle potential parameters have been investigated for the first time. In general, a good description of elastic and inelastic differential and total reactions cross sections for different nuclei using the revealed global parameters has been received within the framework of macroscopic and semi-microscopic approaches

  16. 3D refraction correction and extraction of clinical parameters from spectral domain optical coherence tomography of the cornea.

    Science.gov (United States)

    Zhao, Mingtao; Kuo, Anthony N; Izatt, Joseph A

    2010-04-26

    Capable of three-dimensional imaging of the cornea with micrometer-scale resolution, spectral domain-optical coherence tomography (SDOCT) offers potential advantages over Placido ring and Scheimpflug photography based systems for accurate extraction of quantitative keratometric parameters. In this work, an SDOCT scanning protocol and motion correction algorithm were implemented to minimize the effects of patient motion during data acquisition. Procedures are described for correction of image data artifacts resulting from 3D refraction of SDOCT light in the cornea and from non-idealities of the scanning system geometry performed as a pre-requisite for accurate parameter extraction. Zernike polynomial 3D reconstruction and a recursive half searching algorithm (RHSA) were implemented to extract clinical keratometric parameters including anterior and posterior radii of curvature, central cornea optical power, central corneal thickness, and thickness maps of the cornea. Accuracy and repeatability of the extracted parameters obtained using a commercial 859nm SDOCT retinal imaging system with a corneal adapter were assessed using a rigid gas permeable (RGP) contact lens as a phantom target. Extraction of these parameters was performed in vivo in 3 patients and compared to commercial Placido topography and Scheimpflug photography systems. The repeatability of SDOCT central corneal power measured in vivo was 0.18 Diopters, and the difference observed between the systems averaged 0.1 Diopters between SDOCT and Scheimpflug photography, and 0.6 Diopters between SDOCT and Placido topography.

  17. The determination of kinetic parameters of LiF : Mg,Ti from thermal decaying curves of optical absorption bands

    CERN Document Server

    Yazici, A N

    2003-01-01

    In this paper, the thermal bleaching curves (TBCs) of specific optical absorption bands of LiF : Mg,Ti were measured as a function of temperature. The TBCs obtained were analysed to extract the kinetic parameters (the thermal activation energy (E) and the frequency factor (s)) of some TL glow peaks of LiF : Mg,Ti on the basis of the developed first-order kinetic model over a specified temperature region.

  18. Effect of substrate temperature on the optical parameters of thermally evaporated Ge-Se-Te thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Pankaj, E-mail: pks_phy@yahoo.co.i [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 India (India); Katyal, S.C. [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 India (India)

    2009-05-01

    Thin films of Ge{sub 10}Se{sub 90-x}Te{sub x} (x = 0, 10, 20, 30, 40, 50) glassy alloys were deposited at three substrate temperatures (303 K, 363 K and 423 K) using conventional thermal evaporation technique at base pressure of {approx} 10{sup -4} Pa. X-ray diffraction results show that films deposited at 303 K are of amorphous nature while films deposited at 363 K and 423 K are of polycrystalline nature. The optical parameters, refractive index and optical gap have been derived from the transmission spectra (using UV-Vis-NIR spectrophotometer) of the thin films in the spectral region 400-1500 nm. This has been observed that refractive index values remain almost constant while the optical gap is found to decrease considerably with the increase of substrate temperature. The decrease in optical gap is explained on the basis of change in nature of films, from amorphous to polycrystalline state, with the increase of substrate temperature. The optical gap has also been observed to decrease with the increase of Te content.

  19. In-vivo nonlinear optical microscopy (NLOM) of epithelial-connective tissue interface (ECTI) reveals quantitative measures of neoplasia in hamster oral mucosa.

    Science.gov (United States)

    Pal, Rahul; Yang, Jinping; Ortiz, Daniel; Qiu, Suimin; Resto, Vicente; McCammon, Susan; Vargas, Gracie

    2015-01-01

    The epithelial-connective tissue interface (ECTI) plays an integral role in epithelial neoplasia, including oral squamous cell carcinoma (OSCC). This interface undergoes significant alterations due to hyperproliferating epithelium that supports the transformation of normal epithelium to precancers and cancer. We present a method based on nonlinear optical microscopy to directly assess the ECTI and quantify dysplastic alterations using a hamster model for oral carcinogenesis. Neoplastic and non-neoplastic normal mucosa were imaged in-vivo by both multiphoton autofluorescence microscopy (MPAM) and second harmonic generation microscopy (SHGM) to obtain cross-sectional reconstructions of the oral epithelium and lamina propria. Imaged sites were biopsied and processed for histopathological grading and measurement of ECTI parameters. An ECTI shape parameter was calculated based on deviation from the linear geometry (ΔLinearity) seen in normal mucosa was measured using MPAM-SHGM and histology. The ECTI was readily visible in MPAM-SHGM and quantitative shape analysis showed ECTI deformation in dysplasia but not in normal mucosa. ΔLinearity was significantly (p tissue with 87.9% sensitivity and 97.6% specificity, while calculations from histology provided 96.4% sensitivity and 85.7% specificity. Among other quantifiable architectural changes, a progressive statistically significant increase in epithelial thickness was seen with increasing grade of dysplasia. MPAM-SHGM provides new noninvasive ways for direct characterization of ECTI which may be used in preclinical studies to investigate the role of this interface in early transformation. Further development of the method may also lead to new diagnostic approaches to differentiate non-neoplastic tissue from precancers and neoplasia, possibly with other cellular and layer based indicators of abnormality.

  20. Meta-Analysis of the Structural Equation Models' Parameters for the Estimation of Brain Connectivity with fMRI

    Directory of Open Access Journals (Sweden)

    Joan Guàrdia-Olmos

    2018-02-01

    Full Text Available Structural Equation Models (SEM is among of the most extensively applied statistical techniques in the study of human behavior in the fields of Neuroscience and Cognitive Neuroscience. This paper reviews the application of SEM to estimate functional and effective connectivity models in work published since 2001. The articles analyzed were compiled from Journal Citation Reports, PsycInfo, Pubmed, and Scopus, after searching with the following keywords: fMRI, SEMs, and Connectivity.Results: A 100 papers were found, of which 25 were rejected due to a lack of sufficient data on basic aspects of the construction of SEM. The other 75 were included and contained a total of 160 models to analyze, since most papers included more than one model. The analysis of the explained variance (R2 of each model yields an effect of the type of design used, the type of population studied, the type of study, the existence of recursive effects in the model, and the number of paths defined in the model. Along with these comments, a series of recommendations are included for the use of SEM to estimate of functional and effective connectivity models.

  1. High Speed and High Spatial Density Parameter Measurement Using Fiber Optic Sensing Technology

    Science.gov (United States)

    Parker, Allen R. Jr. (Inventor); Chan, Hon Man (Inventor); Richards, William Lance (Inventor); Piazza, Anthony (Inventor); Hamory, Philip J (Inventor)

    2017-01-01

    The present invention is an improved fiber optic sensing system (FOSS) having the ability to provide both high spatial resolution and high frequency strain measurements. The inventive hybrid FOSS fiber combines sensors from high acquisition speed and low spatial resolution Wavelength-Division Multiplexing (WDM) systems and from low acquisition speed and high spatial resolution Optical Frequency Domain Reflection (OFDR) systems. Two unique light sources utilizing different wavelengths are coupled with the hybrid FOSS fiber to generate reflected data from both the WDM sensors and OFDR sensors operating on a single fiber optic cable without incurring interference from one another. The two data sets are then de-multiplexed for analysis, optionally with conventionally-available WDM and OFDR system analyzers.

  2. Evaluation of texture parameters for the quantitative description of multimodal nonlinear optical images from atherosclerotic rabbit arteries

    Energy Technology Data Exchange (ETDEWEB)

    Mostaco-Guidolin, Leila B; Ko, Alex C-T; Popescu, Dan P; Smith, Michael S D; Kohlenberg, Elicia K; Sowa, Michael G [Institute for Biodiagnostics, National Research Council Canada, Winnipeg, R3B 1Y6 (Canada); Shiomi, Masashi [Institute of Experimental Animals, School of Medicine, Kobe University, Kobe 650-0017 (Japan); Major, Arkady [Department Electrical and Computer Engineering, University of Manitoba, E3-559 Engineering Building, Winnipeg, R3T 5V6 (Canada)

    2011-08-21

    The composition and structure of atherosclerotic lesions can be directly related to the risk they pose to the patient. Multimodal nonlinear optical (NLO) microscopy provides a powerful means to visualize the major extracellular components of the plaque that critically determine its structure. Textural features extracted from NLO images were investigated for their utility in providing quantitative descriptors of structural and compositional changes associated with plaque development. Ten texture parameters derived from the image histogram and gray level co-occurrence matrix were examined that highlight specific structural and compositional motifs that distinguish early and late stage plaques. Tonal-texture parameters could be linked to key histological features that characterize vulnerable plaque: the thickness and density of the fibrous cap, size of the atheroma, and the level of inflammation indicated through lipid deposition. Tonal and texture parameters from NLO images provide objective metrics that correspond to structural and biochemical changes that occur within the vessel wall in early and late stage atherosclerosis.

  3. Experimental investigation on local parameter measurement using optical probes in two-phase flow under rolling condition

    International Nuclear Information System (INIS)

    Tian Daogui; Sun Licheng; Yan Changqi; Liu Guoqiang

    2013-01-01

    In order to get more local interfacial information as well as to further comprehend the intrinsic mechanism of two-phase flow under rolling condition, a method was proposed to measure the local parameters by using optical probes under rolling condition in this paper. An experimental investigation of two-phase flow under rolling condition was conducted using the probe fabricated by the authors. It is verified that the probe method is feasible to measure the local parameters in two'-phase flow under rolling condition. The results show that the interfacial parameters distribution near wall region has a distinct periodicity due to the rolling motion. The averaged deviation of the void fraction measured by the probe from that obtained from measured pressure drop is about 8%. (authors)

  4. Latitudinal variations of aerosol optical parameters over South Africa based on MISR satellite data

    CSIR Research Space (South Africa)

    Tesfaye M

    2010-09-01

    Full Text Available The latitudunal variation of the relative weight size distribution and optical properties of aerosols over South Africa is presented here. The study uses 10-years of Multi-angle Imaging SpectroRadiometer (MISR) satellite data, collected over South...

  5. Terahertz (THz) Optical Parameters of Three-Dimensional (3-D) Printing Materials

    Science.gov (United States)

    2017-03-01

    Terahertz (THz), Submillimeter Wave, Imaging 15. NUMBER OF PAGES 16 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED 18...and imaging has become a topic of research as an optical technique to study these materials because THz radiation can penetrate many visibly opaque...2) Three materials, each tinted with two different colors, were measured. The materials were High Impact polystyrene (HIPS

  6. Determination of the optical parameters of a-Si:H thin films ...

    Indian Academy of Sciences (India)

    single-effective oscillator model to the a-Si:H samples to calculate the optical ..... et al [23] and have similar trend as those shown by El-Sayed and Amin [24]. .... [3] K L Chopra, Thin film phenomena (McGraw-Hill Book Company, USA, 1969).

  7. Optical fibre multi-parameter sensing with secure cloud based signal capture and processing

    Science.gov (United States)

    Newe, Thomas; O'Connell, Eoin; Meere, Damien; Yuan, Hongwei; Leen, Gabriel; O'Keeffe, Sinead; Lewis, Elfed

    2016-05-01

    Recent advancements in cloud computing technologies in the context of optical and optical fibre based systems are reported. The proliferation of real time and multi-channel based sensor systems represents significant growth in data volume. This coupled with a growing need for security presents many challenges and presents a huge opportunity for an evolutionary step in the widespread application of these sensing technologies. A tiered infrastructural system approach is adopted that is designed to facilitate the delivery of Optical Fibre-based "SENsing as a Service- SENaaS". Within this infrastructure, novel optical sensing platforms, deployed within different environments, are interfaced with a Cloud-based backbone infrastructure which facilitates the secure collection, storage and analysis of real-time data. Feedback systems, which harness this data to affect a change within the monitored location/environment/condition, are also discussed. The cloud based system presented here can also be used with chemical and physical sensors that require real-time data analysis, processing and feedback.

  8. Using the Change Manager Model for the Hippocampal System to Predict Connectivity and Neurophysiological Parameters in the Perirhinal Cortex

    Science.gov (United States)

    Coward, L. Andrew; Gedeon, Tamas D.

    2016-01-01

    Theoretical arguments demonstrate that practical considerations, including the needs to limit physiological resources and to learn without interference with prior learning, severely constrain the anatomical architecture of the brain. These arguments identify the hippocampal system as the change manager for the cortex, with the role of selecting the most appropriate locations for cortical receptive field changes at each point in time and driving those changes. This role results in the hippocampal system recording the identities of groups of cortical receptive fields that changed at the same time. These types of records can also be used to reactivate the receptive fields active during individual unique past events, providing mechanisms for episodic memory retrieval. Our theoretical arguments identify the perirhinal cortex as one important focal point both for driving changes and for recording and retrieving episodic memories. The retrieval of episodic memories must not drive unnecessary receptive field changes, and this consideration places strong constraints on neuron properties and connectivity within and between the perirhinal cortex and regular cortex. Hence the model predicts a number of such properties and connectivity. Experimental test of these falsifiable predictions would clarify how change is managed in the cortex and how episodic memories are retrieved. PMID:26819594

  9. Estimating resist parameters in optical lithography using the extended Nijboer-Zernike theory

    NARCIS (Netherlands)

    Dirksen, P.; Braat, J.J.M.; Janssen, A.J.E.M.

    2006-01-01

    This study presents an experimental method to determine the resist parameters at the origin of a general blurring of a projected aerial image. The resist model includes the effects of diffusion in the horizontal plane and image blur that originates from a stochastic variation of the focus parameter.

  10. The nonlinear heat equation with state–dependent parameters and its connection to the Burgers’ and the potential Burgers’ equation

    DEFF Research Database (Denmark)

    Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John-Josef

    2014-01-01

    In this work the stability properties of a nonlinear partial differential equation (PDE) with state–dependent parameters is investigated. Among other things, the PDE describes freezing of foodstuff, and is closely related to the (Potential) Burgers’ Equation. We show that for certain forms of coe...

  11. Effect of substrate baking temperature on zinc sulfide and germanium thin films optical parameters

    Science.gov (United States)

    Liu, Fang; Gao, Jiaobo; Yang, Chongmin; Zhang, Jianfu; Liu, Yongqiang; Liu, Qinglong; Wang, Songlin; Mi, Gaoyuan; Wang, Huina

    2016-10-01

    ZnS and Ge are very normal optical thin film materials in Infrared wave. Studying the influence of different substrate baking temperature to refractive index and actual deposition rates is very important to promote optical thin film quality. In the same vacuum level, monitoring thickness and evaporation rate, we use hot evaporation to deposit ZnS thin film materials and use ion-assisted electron beam to deposit Ge thin film materials with different baking temperature. We measure the spectral transmittance with the spectrophotometer and calculate the actual deposition rates and the refractive index in different temperature. With the higher and higher temperature in a particular range, ZnS and Ge refractive index become higher and actual deposition rates become smaller. The refractive index of Ge film material change with baking temperature is more sensitive than ZnS. However, ZnS film actual deposition rates change with baking temperature is more sensitive than Ge.

  12. Optical movie encryption based on a discrete multiple-parameter fractional Fourier transform

    International Nuclear Information System (INIS)

    Zhong, Zhi; Zhang, Yujie; Shan, Mingguang; Wang, Ying; Zhang, Yabin; Xie, Hong

    2014-01-01

    A movie encryption scheme is proposed using a discrete multiple-parameter fractional Fourier transform and theta modulation. After being modulated by sinusoidal amplitude grating, each frame of the movie is transformed by a filtering procedure and then multiplexed into a complex signal. The complex signal is multiplied by a pixel scrambling operation and random phase mask, and then encrypted by a discrete multiple-parameter fractional Fourier transform. The movie can be retrieved by using the correct keys, such as a random phase mask, a pixel scrambling operation, the parameters in a discrete multiple-parameter fractional Fourier transform and a time sequence. Numerical simulations have been performed to demonstrate the validity and the security of the proposed method. (paper)

  13. A hierarchical cluster analysis of normal-tension glaucoma using spectral-domain optical coherence tomography parameters.

    Science.gov (United States)

    Bae, Hyoung Won; Ji, Yongwoo; Lee, Hye Sun; Lee, Naeun; Hong, Samin; Seong, Gong Je; Sung, Kyung Rim; Kim, Chan Yun

    2015-01-01

    Normal-tension glaucoma (NTG) is a heterogenous disease, and there is still controversy about subclassifications of this disorder. On the basis of spectral-domain optical coherence tomography (SD-OCT), we subdivided NTG with hierarchical cluster analysis using optic nerve head (ONH) parameters and retinal nerve fiber layer (RNFL) thicknesses. A total of 200 eyes of 200 NTG patients between March 2011 and June 2012 underwent SD-OCT scans to measure ONH parameters and RNFL thicknesses. We classified NTG into homogenous subgroups based on these variables using a hierarchical cluster analysis, and compared clusters to evaluate diverse NTG characteristics. Three clusters were found after hierarchical cluster analysis. Cluster 1 (62 eyes) had the thickest RNFL and widest rim area, and showed early glaucoma features. Cluster 2 (60 eyes) was characterized by the largest cup/disc ratio and cup volume, and showed advanced glaucomatous damage. Cluster 3 (78 eyes) had small disc areas in SD-OCT and were comprised of patients with significantly younger age, longer axial length, and greater myopia than the other 2 groups. A hierarchical cluster analysis of SD-OCT scans divided NTG patients into 3 groups based upon ONH parameters and RNFL thicknesses. It is anticipated that the small disc area group comprised of younger and more myopic patients may show unique features unlike the other 2 groups.

  14. Spark Plasma Sintering constrained process parameters of sintered silver paste for connection in power electronic modules: Microstructure, mechanical and thermal properties

    Energy Technology Data Exchange (ETDEWEB)

    Alayli, N. [Université Paris 13, Sorbonne Paris Cité, Laboratoire des Sciences des Procédés et des Matériaux, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3407, 99 avenue Jean Baptiste Clément, F-93430 Villetaneuse (France); Université de Versailles-Saint-Quentin-en-Yvelines, Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Centre National de la Recherche Scientifique/INSU, Laboratoire Atmosphères Milieux Observations Spatiales-IPSL, Quartier des Garennes, 11 Boulevard d' Alembert, F-78280 Guyancourt (France); Schoenstein, F., E-mail: frederic.schoenstein@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, Laboratoire des Sciences des Procédés et des Matériaux, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3407, 99 avenue Jean Baptiste Clément, F-93430 Villetaneuse (France); Girard, A. [Office National d' Étude et de Recherches Aérospatiales, Laboratoire d' Étude des Microstructures, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 104, 29 avenue de la Division Leclerc, F-92322 Châtillon (France); and others

    2014-11-14

    Processing parameters of Spark Plasma Sintering (SPS) technique were constrained to process nano sized silver particles bound in a paste for interconnection in power electronic devices. A novel strategy combining debinding step and consolidation processes (SPS) in order to elaborate nano-structured silver bulk material is investigated. Optimum parameters were sought for industrial power electronics packaging from the microstructural and morphological properties of the sintered material. The latter was studied by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) to determine the density and the grain size of crystallites. Two types of samples, termed S1 (bulk) and S2 (multilayer) were elaborated and characterized. They are homogeneous with a low degree of porosity and a good adhesion to the substrate and the process parameters are compatible with industrial constraints. As the experimental results show, the mean crystallite size is between 60 nm and 790 nm with a density between 50% and 92% resulting in mechanical and thermal properties that are better than that of lead free solder. The best SPS sintering parameters, the applied pressure, the temperature and the processing time were determined as being 3 MPa, 300 °C and 1 min respectively when the desizing time of the preprocessing step was kept below 5 min at 150 °C. Using these processing parameters, acceptable for automotive packaging industry, a semi-conductor power chip was successfully connected to a metalized substrate by sintered silver with thermal and electrical properties better than those of current solders and with thermomechanical properties allowing absorption of thermoplastic stresses. - Highlights: • The sintered silver joints have nanometric structure. • The grain growth was controlled by the SPS sintering parameters. • New connection material improve thermal and electrical properties of current solders. • Interconnection's plastic strain can absorb thermo

  15. Large-scale connection between aerosol optical depth and summer monsoon circulation, and precipitation over northeast Asia

    Science.gov (United States)

    Kim, Sang-Woo; Yoon, Soon-Chang; Choi, Suk-Jin; Choi, In-Jin

    2010-05-01

    We investigated the large-scale connection between columnar aerosol loads and summer monsoon circulation, and also the precipitation over northeast Asia using aerosol optical depth (AOD) data obtained from the 8-year MODIS, AERONET Sun/sky radiometer, and precipitation data acquired under the Global Precipitation Climatology Project (GPCP). These high-quality data revealed the large-scale link between AOD and summer monsoon circulation, precipitation in July over northeast Asian countries, and their distinct spatial and annual variabilities. Compared to the mean AOD for the entire period of 2001-2008, the increase of almost 40-50% in the AOD value in July 2005 and July 2007 was found over the downwind regions of China (Yellow Sea, Korean peninsula, and East Sea), with negative precipitation anomalies. This can be attributable to the strong westerly confluent flows, between cyclone flows by continental thermal low centered over the northern China and anti-cyclonic flows by the western North Pacific High, which transport anthropogenic pollution aerosols emitted from east China to aforementioned downwind high AOD regions along the rim of the Pacific marine airmass. In July 2002, however, the easterly flows transported anthropogenic aerosols from east China to the southwestern part of China in July 2002. As a result, the AOD off the coast of China was dramatically reduced in spite of decreasing rainfall. From the calculation of the cross-correlation coefficient between MODIS-derived AOD anomalies and GPCP precipitation anomalies over the period 2001-2008, we found negative correlations over the areas encompassed by 105-115E and 30-35N and by 120-140E and 35-40N (Yellow Sea, Korean peninsula, and East Sea). This suggests that aerosol loads over these regions are easily influenced by the Asian monsoon flow system and associated precipitation.

  16. Lidar inelastic multiple-scattering parameters of cirrus particle ensembles determined with geometrical-optics crystal phase functions.

    Science.gov (United States)

    Reichardt, J; Hess, M; Macke, A

    2000-04-20

    Multiple-scattering correction factors for cirrus particle extinction coefficients measured with Raman and high spectral resolution lidars are calculated with a radiative-transfer model. Cirrus particle-ensemble phase functions are computed from single-crystal phase functions derived in a geometrical-optics approximation. Seven crystal types are considered. In cirrus clouds with height-independent particle extinction coefficients the general pattern of the multiple-scattering parameters has a steep onset at cloud base with values of 0.5-0.7 followed by a gradual and monotonic decrease to 0.1-0.2 at cloud top. The larger the scattering particles are, the more gradual is the rate of decrease. Multiple-scattering parameters of complex crystals and of imperfect hexagonal columns and plates can be well approximated by those of projected-area equivalent ice spheres, whereas perfect hexagonal crystals show values as much as 70% higher than those of spheres. The dependencies of the multiple-scattering parameters on cirrus particle spectrum, base height, and geometric depth and on the lidar parameters laser wavelength and receiver field of view, are discussed, and a set of multiple-scattering parameter profiles for the correction of extinction measurements in homogeneous cirrus is provided.

  17. Interocular symmetry of retinal nerve fiber layer and optic nerve head parameters measured by Cirrus high-definition optical coherence tomography in a normal pediatric population.

    Science.gov (United States)

    Pawar, Neelam; Maheshwari, Devendra; Ravindran, Meenakshi; Ramakrishnan, Renagappa

    2017-10-01

    To determine interocular differences in the retinal nerve fiber layer (RNFL) and optic nerve head (ONH) parameters in a pediatric population using Cirrus high-definition optical coherence tomography (HD-OCT). Seventy normal Indian children aged 5-17 years presenting to the Pediatric Clinic were included in this observational cross-sectional study. All subjects underwent a comprehensive ophthalmologic examination and an evaluation of the RNFL and ONH by Cirrus HD-OCT. Differences between the right and left eyes were calculated and values were compared by means of a paired t-test. Subjects were also divided into two groups based on age (under or over 10 years of age). Interocular differences in RNFL and ONH parameters together with sex and age variations for these differences were determined. The mean age of studied pediatric population was 11.83 ± 3.3 years (range 5-17). Average RNFL thickness was 94.46 ± 8.7 μm (± SD) (range 77-111). Differences in the average RNFL between right and left eyes were not statistically significant (P = 0.060). Superior quadrant RNFL was thicker in the left eye and temporal quadrant was thicker in the right eye. Among ONH parameters, there were no statistically significant differences in any parameters, except vertical cup-disc (CD) ratio which was significant (P = 0.007). The 2.5%-97.5% limits of asymmetry were 9 μm for average RNFL, 0.14 for average CD ratio, and 0.22 for vertical CD ratio. Mean interocular RNFL thickness differences in superior, superior nasal, and temporal superior quadrants were 10.61 (P sex, while only significant differences with age were observed in 12 clock hour sector analysis, mainly in nasal inferior and inferior quadrant. We report the degree of interocular symmetry of RNFL and ONH parameters measured by Cirrus HD-OCT in a healthy pediatric population. The normal interocular RNFL asymmetry should not exceed 9 μm and vertical CD ratio beyond 0.22 should be considered for further investigations. The

  18. The impact of the proportion of nanoparticles to the spherical microparticles of silver on the connection parameters LTJT

    Science.gov (United States)

    Szałapak, J.; Kiełbasiński, K.; Krzemiński, J.; Jakubowska, M.

    2017-08-01

    There are few EU directives restricting use of lead and other hazardous substances in electronics. That leads to ban Pb- Sn alloy from use, the consequence of which is a search for new ways of preparing joints. One of the discussed solutions is using silver particles in Low Temperature Joining Technique (LTJT). This technique allows to use different conducting pastes and lower their sintering temperatures with the use of pressure. The most popular material for the joining tests was silver. Due to its high melting temperature and high pressures needed for lowering the temperature, silver nanoparticles were considered and tested. The temperatures of sintering decreased to 300ºC and the pressures went down from about 40 to less than 10 MPa. Due to unsatisfactory parameters of such joints, the authors prepared mixtures of spherical, submicron-sized silver particles with nanoparticles. Joints were tested for their electrical and shears strength parameters. In this article, the authors show the comparison of different variations of the mixtures with joints prepared only with nanoparticles.

  19. Laser parameters, focusing optics, and side effects in femtosecond laser corneal surgery

    Science.gov (United States)

    Plamann, Karsten; Nuzzo, Valeria; Peyrot, Donald A.; Deloison, Florent; Savoldelli, Michèle; Legeais, Jean-Marc

    2008-02-01

    Nowadays, femtosecond lasers are routinely used in refractive eye surgery. Until recently, commercialised clinical systems were exclusively based on ytterbium or neodymium-doped solid state lasers emitting sub-picosecond pulses at a wavelength of about 1 μm and repetition rates of a few 10 kHz. These systems use pulse energies in the μJ range and focussing optics of NA = 0.3 to 0.5. Recent developments have provided a variety of alternative and equally viable approaches: systems are now available using nJ pulses at high numerical apertures and MHz repetition rates - an approach so far only used for femtosecond cell surgery - and fibre laser technology is now being used for femtosecond laser corneal surgery. Recent research has also provided more insight in side effects occurring in present systems: self focusing phenomena and so far unexplained periodical structures have been observed even at high numerical apertures (NA >> 0.5) and moderate pulse energies. The interaction of femtosecond laser pulses with strongly scattering tissue has been studied in view of extending the application of femtosecond lasers to keratoplasty for opaque corneas and to glaucoma surgery. The use of new laser wavelengths and adaptive optics has been proposed. Despite the reputation of femtosecond surgical systems for their precision, repeatability and the absence of secondary effects or complications, a closer examination reveals the presence of subtle phenomena which merit further investigation. We present three of these phenomena: the influence of optical aberration on the quality of the incision, the occurrence of filamentation effects, and the deposit of microscopic glass fragments when performing penetrating incisions.

  20. Estimating Soil and Vegetation Parameters using Synergies between Optical and Microwave Observations

    Science.gov (United States)

    Timmermans, J.; Gomez-Dans, J. L.; Lewis, P.; Loew, A.; Schlenz, F.; Mathieu, P. P.; Pounder, N. L.; Styles, J.

    2017-12-01

    The large amount of remote sensing data available provides a huge potential for various applications, such as crop monitoring. This potential has not been realized yet because inversion-algorithms mostly use a single sensor approach. Consequently, products that combine different low-level observations from different sensors are hard to find. The difficulty in a multi-sensor approach is that 1) different sensor types (microwave/ optical) require different radiative transfer (RT) models and 2) it require consistency between the models. The goal of this research was to investigate the synergistic potential of integrating optical (Opt) and passive microwave (PM) RT models within the Earth Observation Land Data Assimilation System (EOLDAS). EOLDAS uses a Bayesian data assimilation approach together with observation operators such as PROSAIL to estimate state variables. In order to use PM observations, the Community Microwave Emission Model was integrated into the system. Results show a high potential when both Opt and PM observations are used independently. Using only RapidEye only with SAIL RT model, LAI was estimated with R=0.68, with leaf water content and dry matter having lower correlations |R|<0.4. Results for retrieving soil temperature and leaf area index retrievals using only Elbarra observations were good with respectively R=[0.85, 0.79], and for soil moisture also very good with R=0.73 (focusing on dry-spells of at least 9 days only), and with R=0.89 and R=0.77 for respectively the trend and anomalies. Synergistically using Opt and MW observations also shows good potential. Results show that absolute errors decreased (with RMSE=1.22 and S=0.89), but with lower R=0.59; sparse optical observations only improved part of the temporal domain. This shows that PM observations provide good information for the overall trend of the retrieved LAI due to the regular acquisitions, while Opt observations provides better information of the absolute values of the LAI.

  1. Fiber-Optic Chemiluminescent Biosensors for Monitoring Aqueous Alcohols and Other Water Quality Parameters

    Science.gov (United States)

    Verostko, Charles E. (Inventor); Atwater, James E. (Inventor); Akse, James R. (Inventor); DeHart, Jeffrey L. (Inventor); Wheeler, Richard R. (Inventor)

    1998-01-01

    A "reagentless" chemiluminescent biosensor and method for the determination of hydrogen peroxide, ethanol and D-glucose in water is disclosed. An aqueous stream is basified by passing it through a solid phase base bed. Luminol is then dissolved in the basified effluent at a controlled rate. Oxidation of the luminol is catalyzed by the target chemical to produce emitted light. The intensity of the emitted light is detected as a measure of the target chemical concentration in the aqueous stream. The emitted light can be transmitted by a fiber optic bundle to a remote location from the aqueous stream for a remote reading of the target chemical concentration.

  2. Distributed dual-parameter optical fiber sensor based on cascaded microfiber Fabry-Pérot interferometers

    Science.gov (United States)

    Xiang, Yang; Luo, Yiyang; Zhang, Wei; Liu, Deming; Sun, Qizhen

    2017-04-01

    We propose and demonstrate a distributed fiber sensor based on cascaded microfiber Fabry-Perot interferometers (MFPI) for simultaneous refractive index (SRI) and temperature measurement. By employing MFPI which is fabricated by taper-drawing the center of a uniform fiber Bragg grating (FBG) on standard fiber into a section of microfiber, dual parameters including SRI and temperature can be detected through demodulating the reflection spectrum of the MFPI. Further, wavelength-division-multiplexing (WDM) is applied to realize distributed dual-parameter fiber sensor by using cascaded MFPIs with different Bragg wavelengths. A prototype sensor system with 5 cascaded MFPIs is constructed to experimentally demonstrate the sensing performance.

  3. Calculation of the electronic structure optical transitions and contact hyperfine parameters of interstitial hydrogen in alkaline halogen crystals

    International Nuclear Information System (INIS)

    Maciel, A.K.A.

    1977-03-01

    The electronic structure of the interstitial hydrogen atom in KF, NaCl, KCl, and RbCl cristals has been studied using the self-consistent-field multiple-scattering Xα method. In the present calculation a cluster constituted by the hydrogen atom surrounded by its first anion and cation neighbors in a cubic shell has been used. The optical transition energies and hyperfine contact parameters with the interstitial proton and the first shell nuclei have been evaluated. The agreement obtained with the experimental data and the relative independence of the method under variations of its intrinsic parameters, indicate that this method can be adequate to the study of defects in ionic cristals. (author) [pt

  4. Evaluation of optical remote sensing parameters to improve modeling of gross primary productivity in a heterogeneous agricultural area

    Science.gov (United States)

    Schickling, A.; Damm, A.; Schween, J.; Rascher, U.; Crewell, S.; Wahner, A.

    2011-12-01

    Terrestrial photosynthesis greatly determines plant mediated exchange processes in the vegetation atmosphere system and substantially influences patterns in atmospheric carbon dioxide (CO2) concentrations and water vapor. Therefore, an accurate quantification of photosynthetic CO2 uptake, commonly referred to as gross primary productivity (GPP), is a key parameter to distinguish those atmospheric patterns on various spatio-temporal scales. Remote sensing (RS) offers the unique possibility to determine GPP at different spatial scales ranging from the local to the global scale. Attempts to estimate GPP from RS data focus on the light use efficiency (LUE) concept of Monteith which relates GPP to the absorbed photosynthetically active radiation and the efficiency of plant canopies to utilize the absorbed radiation for photosynthesis. To reliably predict GPP on different spatio-temporal scales LUE has to be linked to optical RS parameters which detect changes in photosynthetic efficiency due to environmental conditions. In this study we evaluated two optical RS parameters, namely the sun-induced fluorescence (Fs) and the photochemical reflectance index (PRI), for their potential to serve as a proxy for LUE. The parameters were derived from two ASD FieldSpec spectrometers which were operated in parallel. During several days one instrument was installed on the ground above the vegetation canopy of either a winter wheat or a sugar beet field. The second instrument was operated from a small research aircraft continuously crossing the observation sites at low altitude (sugar beet fields during the day. Results of this spatio-temporal investigation revealed a significant variability of GPP between different winter wheat fields compared to the within-field variability. In addition to the significant between-field variability of sugar beet the results also showed an increase of the within-field variability in the afternoon. Moreover, for the first time it could be shown that

  5. High performance EUV multilayer structures insensitive to capping layer optical parameters.

    Science.gov (United States)

    Pelizzo, Maria Guglielmina; Suman, Michele; Monaco, Gianni; Nicolosi, Piergiorgio; Windt, David L

    2008-09-15

    We have designed and tested a-periodic multilayer structures containing protective capping layers in order to obtain improved stability with respect to any possible changes of the capping layer optical properties (due to oxidation and contamination, for example)-while simultaneously maximizing the EUV reflection efficiency for specific applications, and in particular for EUV lithography. Such coatings may be particularly useful in EUV lithographic apparatus, because they provide both high integrated photon flux and higher stability to the harsh operating environment, which can affect seriously the performance of the multilayer-coated projector system optics. In this work, an evolutive algorithm has been developed in order to design these a-periodic structures, which have been proven to have also the property of stable performance with respect to random layer thickness errors that might occur during coating deposition. Prototypes have been fabricated, and tested with EUV and X-ray reflectometry, and secondary electron spectroscopy. The experimental results clearly show improved performance of our new a-periodic coatings design compared with standard periodic multilayer structures.

  6. Effect of sputtering parameters on optical and electrical properties of ITO films on PET substrates

    International Nuclear Information System (INIS)

    Tseng, Kun-San; Lo, Yu-Lung

    2013-01-01

    The optical and electrical properties of indium tin oxide (ITO) thin films deposited on flexible polyethylene terephthalate (PET) substrates using a DC magnetron sputtering technique are investigated as a function of the deposition time, the argon flow rate and the target–substrate distance. It is found that all of the ITO films contain a high fraction of amorphous phase. The volume fraction of crystallite precipitates in the amorphous host increases with an increasing deposition time or a reducing argon flow rate. The deposition time and argon flow rate have higher effects on the optical transparency of the ITO films than the target–substrate distance has. Increasing film thickness is not the only reason for the transmittance reduced. It is found that an increase of the extinction coefficient by increasing deposition time or an increase of the refractive index by decreasing argon flow rate also reduces the transmittance of thin film. For a constant deposition time, the resistivity of the ITO films reduces with a reducing argon flow rate or a reducing target–substrate distance. For a constant argon flow rate, a critical value of the deposition time exists at which both the resistivity and the effect of the target–substrate distance are minimized. Finally, it is concluded that the film resistivity has low sensitivity to the target–substrate distance if the best deposition conditions which mostly attain the lowest resistivity are matched.

  7. Effect of sputtering parameters on optical and electrical properties of ITO films on PET substrates

    Science.gov (United States)

    Tseng, Kun-San; Lo, Yu-Lung

    2013-11-01

    The optical and electrical properties of indium tin oxide (ITO) thin films deposited on flexible polyethylene terephthalate (PET) substrates using a DC magnetron sputtering technique are investigated as a function of the deposition time, the argon flow rate and the target-substrate distance. It is found that all of the ITO films contain a high fraction of amorphous phase. The volume fraction of crystallite precipitates in the amorphous host increases with an increasing deposition time or a reducing argon flow rate. The deposition time and argon flow rate have higher effects on the optical transparency of the ITO films than the target-substrate distance has. Increasing film thickness is not the only reason for the transmittance reduced. It is found that an increase of the extinction coefficient by increasing deposition time or an increase of the refractive index by decreasing argon flow rate also reduces the transmittance of thin film. For a constant deposition time, the resistivity of the ITO films reduces with a reducing argon flow rate or a reducing target-substrate distance. For a constant argon flow rate, a critical value of the deposition time exists at which both the resistivity and the effect of the target-substrate distance are minimized. Finally, it is concluded that the film resistivity has low sensitivity to the target-substrate distance if the best deposition conditions which mostly attain the lowest resistivity are matched.

  8. Effect of sputtering parameters on optical and electrical properties of ITO films on PET substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Kun-San [Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lo, Yu-Lung, E-mail: loyl@mail.ncku.edu.tw [Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan (China)

    2013-11-15

    The optical and electrical properties of indium tin oxide (ITO) thin films deposited on flexible polyethylene terephthalate (PET) substrates using a DC magnetron sputtering technique are investigated as a function of the deposition time, the argon flow rate and the target–substrate distance. It is found that all of the ITO films contain a high fraction of amorphous phase. The volume fraction of crystallite precipitates in the amorphous host increases with an increasing deposition time or a reducing argon flow rate. The deposition time and argon flow rate have higher effects on the optical transparency of the ITO films than the target–substrate distance has. Increasing film thickness is not the only reason for the transmittance reduced. It is found that an increase of the extinction coefficient by increasing deposition time or an increase of the refractive index by decreasing argon flow rate also reduces the transmittance of thin film. For a constant deposition time, the resistivity of the ITO films reduces with a reducing argon flow rate or a reducing target–substrate distance. For a constant argon flow rate, a critical value of the deposition time exists at which both the resistivity and the effect of the target–substrate distance are minimized. Finally, it is concluded that the film resistivity has low sensitivity to the target–substrate distance if the best deposition conditions which mostly attain the lowest resistivity are matched.

  9. Electron-optical design parameters for a high-resolution electron monochromator

    International Nuclear Information System (INIS)

    Tanaka, H.; Huebner, R.H.

    1976-01-01

    Detailed design parameters of a new, high-resolution electron monochromator are presented. The design utilizes a hemispherical filter as the energy-dispersing element and combines both cylindrical and aperture electrostatic lenses to accelerate, decelerate, transport, and focus the electron beam from the cathode to the interaction region

  10. Optical programmable metamaterials

    Science.gov (United States)

    Gong, Cheng; Zhang, Nan; Dai, Zijie; Liu, Weiwei

    2018-02-01

    We suggest and demonstrate the concept of optical programmable metamaterials which can configure the device's electromagnetic parameters by the programmable optical stimuli. In such metamaterials, the optical stimuli produced by a FPGA controlled light emitting diode array can switch or combine the resonance modes which are coupled in. As an example, an optical programmable metamaterial terahertz absorber is proposed. Each cell of the absorber integrates four meta-rings (asymmetric 1/4 rings) with photo-resistors connecting the critical gaps. The principle and design of the metamaterials are illustrated and the simulation results demonstrate the functionalities for programming the metamaterial absorber to change its bandwidth and resonance frequency.

  11. Comprehensive Study of Z-Cut Highly Integrated LiNbO3 Optical Modulator with Adjustable Chirp Parameters

    Science.gov (United States)

    Palodiya, Vikram; Raghuwanshi, Sanjeev Kumar

    2017-12-01

    In this paper, the domain inversion is used in a simple fashion to improve the performance of a Z-cut highly integrated LiNbO3 optical modulator (LNOM). The Z-cut modulator having ≤ 3 V switching voltage and bandwidth of 15 GHz for an external modulator in which traveling-wave electrode length L_{m} imposed the modulating voltage, the product of V_π and L_{m} is fixed for a given electro-optic material (EOM). An investigation to achieve a low V_π by both magnitude of the electro-optic coefficient (EOC) for a wide variety of EOMs has been reported. The Sellmeier equation (SE) for the extraordinary index of congruent LiNbO3 is derived. The predictions related to phase matching are accurate between room temperature and 250 °C and wavelength ranging from 0.4 to 5 μm. The SE predicts more accurate refractive indices (RI) at long wavelengths. The different overlaps between the waveguides for the Z-cut structure are shown to yield a chirp parameter that can able to adjust 0-0.7. Theoretical results are perfectly verified by simulated results.

  12. Assessment of quality parameters in grapes during ripening using a miniature fiber-optic near-infrared spectrometer.

    Science.gov (United States)

    Fernández-Novales, Juan; López, María-Isabel; Sánchez, María-Teresa; García-Mesa, José-Antonio; González-Caballero, Virginia

    2009-01-01

    Changes in the chemical properties of wine grapes during ripening were studied using near-infrared (NIR) spectroscopy. A miniature fiber-optic NIR spectrometer system working in transmission mode in the spectral region (700 - 1,060 nm) was evaluated for this purpose. Spectra and analytical data were used to develop partial least square calibration models to quantify changes in the major parameters used to chart ripening in this fruit. NIR spectroscopy provided excellent precision for soluble solid content and for reducing sugars, and good precision for maturity index, while for pH and titratable acidity the miniature NIR spectroscopy instrument proved less accurate. The performance of the instrument in classifying wine grapes by grape type and by irrigation regime was also studied. Percentages of correctly classified samples ranged from 82.7% to 96.2%. The results show that the monitoring of soluble solid content and reducing sugars' changes in wine grape quality parameters during ripening, as well as the classification of grapes, can be performed non-destructively using a miniature fiber-optic NIR spectrometer.

  13. Development of time-resolved optical measurement and diagnostic system for parameters of high current and pulsed electron beam

    International Nuclear Information System (INIS)

    Jiang Xiaoguo; Wang Yuan; Yang Guojun; Xia Liansheng; Li Hong; Zhang Zhuo; Liao Shuqing; Shi Jinshui

    2013-01-01

    The beam parameters measurement is the most important work for the study of linear induction accelerator(LIA). The beam parameters are important to evaluate the character of the beam. The demands of beam parameters measurement are improving while the development of accelerator is improving. The measurement difficulty feature higher time-resolved ability, higher spatial resolution, larger dynamic range and higher intuitionistic view data. The measurement technology of beam spot, beam emittance, beam energy have been developed for the past several years. Some high performance equipment such as high speed framing camera are developed recently. Under this condition, the relative integrated optical measurement and diagnostic system for the beam parameters is developed based on several principles. The system features time-resolved ability of up to 2 ns, high sensitivity and large dynamic range. The processing program is compiled for the data process and the local real-time process is reached. The measurement and diagnostic system has provided full and accurate data for the debug work and has been put into applications. (authors)

  14. Hydrophysical correlation and water mass indication of optical physiological parameters of picophytoplankton in Prydz Bay during autumn 2008.

    Science.gov (United States)

    Zhang, Fang; Ma, Yuxin; Lin, Ling; He, Jianfeng

    2012-12-01

    Flow cytometry (FCM) is efficient in detecting both abundance and optical physiological parameters including cell size and cellular carbon content-side scatter (SSC), carotenoids-green and orange fluorescence (FL1 and FL2), and red fluorescence-chlorophylls (FL3) can be obtained by FCM. The utilization of these physiological parameters in indicating water masses in Prydz Bay was investigated for the first time. Picophytoplankton were very sensitive to hydrophysical changes and present distinct characteristics of water masses: Picophytoplankton in water closer to the Amery Ice Shelf were more affected by salinity than by temperature, while temperature became more important than salinity the nearer the picophytoplankton were to the deep sea. The picophytoplankton dealt with declines in light by increasing the size of cells, which increase the fixation of carbon. This can also be increased by high temperature and salinity. Pure water masses can increase the content of chlorophylls and cellular carbon. Generally, the distributions of all the five parameters at upper water depths were less affected by temperature and salinity than by water masses; and these parameters can be as indicators to Summer Surface Water (SSW), Winter Water (WW) and Continental Shelf Water (CSW). Copyright © 2012 Elsevier B.V. All rights reserved.

  15. [Measurement of plasma parameters in slot microplasma by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Lü, Ying-Hui; Liu, Wei-Yuan; Yue, Han; Lu, Ning; Li, Xin-Chun

    2010-12-01

    Slot microplasma was generated in argon and air mixture by using dielectric barrier discharge device with two parallel water electrodes. The molecular vibrational temperature, molecular rotational temperature and average electron energy of the slot plasma were studied by optical emission spectrum. The molecular vibrational temperature was calculated using the second positive system of nitrogen molecules ( C3 pi(u) --> B3 pi(g)). The molecular rotational temperature was calculated using the first negative system of nitrogen molecular ions ( B 2sigma(u)+ --> X sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391.4 nm) and nitrogen molecules in the excitation level (337.1 nm) emission spectrum line were measured for studying the variations of electron energy. It was found that the molecular vibrational temperature, molecular rotational temperature and average electron energy decrease with gas pressure increasing.

  16. Thermotropic resin systems. Relationships between formulation parameters, material structure and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Resch, Katharina [Polymer Competence Center Leoben GmbH, Leoben (Austria); Wallner, Gernot M. [Univ. of Leoben (Austria)

    2008-07-01

    This paper focuses on a comprehensive characterization of various thermotropic resins under polymer physical aspects. Numerous thermotropic layers were produced under systematic variation of resin base, thermotropic additives and additive concentration. A detailed investigation of optical properties, switching temperature, switching process and residual transmittance was performed with a UV/Vis/NIR spectrophotometer. Switching temperatures are compared with thermal transitions in the material determined by Differential Scanning Calorimetry (DSC). Whereas the different film types show a direct solar transparency between 64 and 83% in the clear state, the direct solar transmittance decreases to values of about 27% to 80% above the switching temperature. In general the thermotropic resins are characterized by a steep and rapid switching process. The switching temperature can be adapted by varying the additives. The comparison of films thermal transitions with the switching performance reveals a good correlation. (orig.)

  17. [Measurement of plasma parameters in cluster hexagon pattern discharge by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Shen, Zhong-Kai; Li, Xin-Chun; Liu, Liang; Lu, Ning; Shang, Jie

    2012-09-01

    The cluster hexagon pattern was obtained in a dielectric barrier discharge in air/argon for the first time. Three plasma parameters, i. e. the molecular vibrational temperature, the molecular rotational temperature and the average electron energy of individual cluster in cluster hexagon pattern discharge, were studied by changing the air content. The molecular vibrational temperature and the molecular rotational temperature were calculated using the second positive band system of nitrogen molecules (C 3IIu --> B 3IIg) and the first negative band system of nitrogen molecular ions (B 2Sigma(u)+ --> Chi2 Sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391. 4 nm) and nitrogen molecules emission spectrum line (337.1 nm) were analyzed for studying the variations of the electron energy. It was found that the three plasma parameters of individual cluster in cluster hexagon pattern increase with air content increasing from 16% to 24%.

  18. Long-term measurements of aerosol optical parameters in Athens, Greece

    Science.gov (United States)

    Paraskevopoulou, Despoina; Liakakou, Eleni; Gerasopoulos, Evangelos; Mihalopoulos, Nikolaos

    2015-04-01

    Aerosol chemical composition was studied in conjunction with its optical properties in the area of Athens Greece. For this purpose, sampling of fine aerosol fraction (PM2,5) took place on a daily basis from August 2010 to April 2013 at an urban background location. The samples are subsequently analyzed for their content in organic (OC) and elemental carbon (EC), major ions and trace metals, resulting in the exercise of chemical mass closure. In parallel, the optical properties of aerosols are recorded using a nephelometer and a particle soot absorption photometer (PSAP), leading to the calculation of scattering (σscat) and absorption (σabs) coefficients, respectively; while single scattering albedo (SSA) and mass scattering and absorption efficiencies are thereinafter calculated. Daily σscat values provide an average of 30.1±3.9 Μm-1 while, the average of σabs is 5.2±1.4 Μm-1. The seasonal cycle of σscat presents maximum during summer and in November, due to long-range transport of aerosol from continental Europe and dust transfer from Africa, respectively. The estimated mass absorption efficiency of EC is estimated to be 8.3±0.2 m2 g-1 for the whole studied period, while the corresponding estimated mass scattering efficiency of PM2.5 is 1.7±0.1 m2 g-1 and does not affected by the presence of dust. The average SSA equals to 0.87±0.11 for the three-year period. On a seasonal basis, SSA presents maximum values during summer that is consistent with the reduction of EC - the main absorbing specie. Finally, the reconstruction of scattering coefficients was performed taking into consideration the measured chemistry of fine aerosol.

  19. Analytical Assessment of the Relationship between 100MWp Large-scale Grid-connected Photovoltaic Plant Performance and Meteorological Parameters

    Science.gov (United States)

    Sheng, Jie; Zhu, Qiaoming; Cao, Shijie; You, Yang

    2017-05-01

    This paper helps in study of the relationship between the photovoltaic power generation of large scale “fishing and PV complementary” grid-tied photovoltaic system and meteorological parameters, with multi-time scale power data from the photovoltaic power station and meteorological data over the same period of a whole year. The result indicates that, the PV power generation has the most significant correlation with global solar irradiation, followed by diurnal temperature range, sunshine hours, daily maximum temperature and daily average temperature. In different months, the maximum monthly average power generation appears in August, which related to the more global solar irradiation and longer sunshine hours in this month. However, the maximum daily average power generation appears in October, this is due to the drop in temperature brings about the improvement of the efficiency of PV panels. Through the contrast of monthly average performance ratio (PR) and monthly average temperature, it is shown that, the larger values of monthly average PR appears in April and October, while it is smaller in summer with higher temperature. The results concluded that temperature has a great influence on the performance ratio of large scale grid-tied PV power system, and it is important to adopt effective measures to decrease the temperature of PV plant properly.

  20. Determination of Morphological Parameters of Supported Gold Nanoparticles: Comparison of AFM Combined with Optical Spectroscopy and Theoretical Modeling versus TEM

    Directory of Open Access Journals (Sweden)

    Frank Hubenthal

    2012-07-01

    Full Text Available The morphology of small gold particles prepared by Volmer–Weber growth on sapphire substrates have been investigated by two different characterization techniques. First, by non-extensive atomic force microscopy (AFM in combination with optical spectroscopy and modeling of the optical properties using a theoretical model, recently developed in our group. Second, by extensive transmission electron microscopy (TEM. Comparing the results obtained with both techniques demonstrate that for small gold nanoparticles within the quasistatic limit, the morphological properties can be precisely determined by an appropriate theoretical modeling of the optical properties in combination with simple AFM measurements. The apparent mean axial ratio of the nanoparticles, i.e., the axial ratio that corresponds to the center frequency of the ensemble plasmon resonance, is obtained easily from the extinction spectrum. The mean size is determined by the nanoparticle number density and the amount of deposited material, measured by AFM and a quartz micro balance, respectively. To extract the most probable axial ratio of the nanoparticle ensemble, i.e., the axial ratio that corresponds to the most probable nanoparticle size in the ensemble, we apply the new theoretical model, which allows to extract the functional dependence of the nanoparticle shape on its size. The morphological parameters obtained with this procedure will be afterwards compared to extensive TEM measurements. The results obtained with both techniques yield excellent agreement. For example, the lateral dimensions of the nanoparticles after deposition of 15.2 × 1015 atoms/cm2 of gold has been compared. While a mean lateral diameter of (13 ± 2 nm has been extracted from AFM, optical spectroscopy and modeling, a value of (12 ± 2 nm is derived from TEM. The consistency of the results demonstrate the precision of our new model. Moreover, since our theoretical model allows to extract the functional

  1. Effect of compositional dependence on physical and optical parameters of Te{sub 17}Se{sub 83−x}Bi{sub x} glassy system

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Pankaj, E-mail: pks_phy@yahoo.co.in [Department of Physics and Materials Science, Jaypee University of Information Technology, Waknaghat, Solan, HP 173234 (India); El-Bana, M.S.; Fouad, S.S. [Nano-Science and Semiconductor Laboratories, Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt); Sharma, Vineet [Department of Physics and Materials Science, Jaypee University of Information Technology, Waknaghat, Solan, HP 173234 (India)

    2016-05-15

    In the present paper we have studied the effect of Bi addition on the physical and optical properties of thermally evaporated Te{sub 17}Se{sub 83−x}Bi{sub x} thin films. With Bi addition the density, mean coordination number, mechanical constraints, glass transition temperature increases. The other parameters theoretical energy gap, lone pair electron, deviation from stoichiometry decreases. Transmission spectra have been taken in the spectral range 400 nm–2500 nm using ultraviolet–visible–near infrared spectrophotometer. The fundamental absorption edge shifts towards longer wavelength with Bi incorporation. Optical energy gap and linear refractive index have been determined using transmission spectra. A good correlation has been drawn between the optical and theoretical parameters. Using linear optical parameters, the nonlinear optical susceptibility and nonlinear refractive index have been estimated. - Highlights: • Physical and optical parameters have been analyzed for Te{sub 17}Se{sub 83−x}Bi{sub x} glassy alloys. • The addition of Bi leads to decrease of average heat of atomization and cohesive energy. • The optical band gap decreases with increasing Bi content. • The third order susceptibility and nonlinear refractive index show an increase with increase in the Bi content.

  2. Gaussian optics calculations of the parameters of a magnetic sector energy analyzer

    International Nuclear Information System (INIS)

    Zaluzec, N.J.

    1978-01-01

    The design of a magnetic deflection system for use as an electron energy loss spectrometer can be a complex process if one takes the most general approach. However, for application to materials research the design process can be reduced to three basic steps. First, the qualitative features of the overall system are defined--i.e., incident electron energy, required resolution, type of magnet, the desired focal properties, etc. Secondly, the design parameters necessary to meet these requirements are calculated using the appropriate equations. Finally, once the magnetic field has been specified, ray-tracing techniques can be employed to verify the system response to the conditions defined in the first two steps. The calculation of the parameters of a uniform field magnetic sector analyzer capable of energy resolutions of 20 ppM or better are considered. Higher resolution is attainable; however, for most materials work, more important considerations are the attainment of double focusing to improve S/N, the minimization of aberrations and the achievement of a flat image plane to facilitate parallel data recording

  3. Simulation of beam-splitter made of metamaterials with angle spatial distribution of constitutive parameters based on transformation optics for THz frequency range

    International Nuclear Information System (INIS)

    Gurvitz, E A; Vozianova, A V; Khodzitsky, M K

    2014-01-01

    New approach to design beam splitter on basis of the transformation optics using angle constitutive parameters distribution of medium was proposed. The beam splitter was numerically simulated by COMSOL Multiphysics for terahertz frequency range. The numerical simulations were carried out for ideal and reduced constitutive parameters of medium for the case of TM plane wave

  4. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  5. An optimized knife-edge method for on-orbit MTF estimation of optical sensors using powell parameter fitting

    Science.gov (United States)

    Han, Lu; Gao, Kun; Gong, Chen; Zhu, Zhenyu; Guo, Yue

    2017-08-01

    On-orbit Modulation Transfer Function (MTF) is an important indicator to evaluate the performance of the optical remote sensors in a satellite. There are many methods to estimate MTF, such as pinhole method, slit method and so on. Among them, knife-edge method is quite efficient, easy-to-use and recommended in ISO12233 standard for the wholefrequency MTF curve acquisition. However, the accuracy of the algorithm is affected by Edge Spread Function (ESF) fitting accuracy significantly, which limits the range of application. So in this paper, an optimized knife-edge method using Powell algorithm is proposed to improve the ESF fitting precision. Fermi function model is the most popular ESF fitting model, yet it is vulnerable to the initial values of the parameters. Considering the characteristics of simple and fast convergence, Powell algorithm is applied to fit the accurate parameters adaptively with the insensitivity to the initial parameters. Numerical simulation results reveal the accuracy and robustness of the optimized algorithm under different SNR, edge direction and leaning angles conditions. Experimental results using images of the camera in ZY-3 satellite show that this method is more accurate than the standard knife-edge method of ISO12233 in MTF estimation.

  6. ZZ-CENPL, Chinese Evaluated Nuclear Parameter Library. ZZ CENPL-DLS, Discrete Level Schemes and Gamma Branching Ratios Library; ZZ CENPL-FBP, Fission Barrier Parameter Library; ZZ CENPL-GDRP, Giant Dipole Resonance Parameter Library; ZZ CENPL-NLD, Nuclear Level Density Parameter Library; ZZ CENPL-MCC, Nuclear Ground State Atomic Masses Library; ZZ CENPL-OMP, Optical Model Parameter Library

    International Nuclear Information System (INIS)

    Su Zongdi

    1995-01-01

    Description of program or function: CENPL - GDRP (Giant Dipole Resonance Parameters for Gamma-Ray): - Format: special format described in documentation; - Nuclides: V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Lu, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, Th, U, Np, Pu. - Origin: Experimental values offered by S.S. Dietrich and B.L. Berman. CENPL - FBP (Fission Barrier Parameter Sub-Library): - Format: special format described in documentation; - Nuclides: (1) 51 nuclei region from Th-230 to Cf-255, (2) 46 nuclei region from Th-229 to Cf-253, (3) 24 nuclei region from Pa-232 to Cf-253; - Origin: (1) Lynn, (2) Analysis of experimental data by Back et al., (3) Ohsawa. CENPL - DLS (Discrete level scheme and branch ratio of gamma decay: - Format: Special format described in documentation; - Origin: ENSDF - BNL. CENPL - NLD (Nuclear Level Density): - Format: Special format described in documentation; - Origin: Huang Zhongfu et al. CENPL - OMP (Optical model parameter sub-library): - Format: special format described in documentation ; - Origin: CENDL, ENDF/B-VI, JENDL-3. CENPL - MC (I) and (II) (Atomic masses and characteristic constants for nuclear ground states) : - Format: Brief table format; - Nuclides: 4760 nuclides ranging from Z=0 A=1 to Z=122 A=318. - Origin: Experimental data and systematic results evaluated by Wapstra, theoretical results calculated by Moller, ENSDF - BNL and Nuclear Wallet Cards. CENPL contains the following six sub-libraries: 1. Atomic Masses and Characteristic Constants for nuclear ground states (MCC). This data consists of calculated and in most cases also measured mass excesses, atomic masses, total binding energies, spins, parities, and half-lives of nuclear ground states, abundances, etc. for 4800 nuclides. 2. Discrete Level Schemes and branching ratios of gamma decay (DLS). The data on nuclear discrete levels are based on the Evaluated

  7. Integration of optical and chemical parameters to improve the particulate matter characterization

    Science.gov (United States)

    Perrone, M. R.; Romano, S.; Genga, A.; Paladini, F.

    2018-06-01

    Integrating nephelometer measurements have been combined with co-located in space and time PM10 and PM1 mass concentration measurements to highlight the benefits of integrating aerosol optical properties with the chemical speciation of PM1 and PM10 samples. Inorganic ions (SO42-, NO3-, NH4+, Cl-, Na+, K+, Mg2+, and Ca2+), metals (Fe, Al, Zn, Ti, Cu, V, Mn, and Cr), and the elemental and organic carbon (EC and OC, respectively) have been monitored to characterize the chemical composition of PM1 and PM10 samples, respectively. The scattering coefficient (σp) at 450 nm, the scattering Ångström coefficient (Å) calculated at the 450-635 nm wavelength pair, and the scattering Ångström coefficient difference (ΔÅ) retrieved from nephelometer measurements have been used to characterize the optical properties of the particles at the surface. The frequency distribution of the Å daily means during the one-year monitoring campaign, performed at a southeastern Italian site, has allowed identifying three main Å variability ranges: Å ≤ 0.8, 0.8 1.2. We found that σp and ΔÅ mean values and the mean chemical composition of the PM1 and PM10 samples varied with the Å variability range. σp and ΔÅ reached the highest (149 Mm-1) and the smallest (0.16) mean value, respectively, on the days characterized by Å > 1.2. EC, SO42-, and NH4+ mean mass percentages also reached the highest mean value on the Å > 1.2 days, representing on average 8.4, 9.8, and 4.2%, respectively, of the sampled PM10 mass and 12.4, 10.6, and 7.7%, respectively, of the PM1 mass. Conversely, σp and ΔÅ mean values were equal to 85 Mm-1 and 0.55, respectively, on the days characterized by Å ≤ 0.8 and the EC, SO42-, and NH4+ mean mass percentages reached smaller values on the Å ≤ 0.8 days, representing 4.5, 6.0, and 1.9% of the PM10 mass and 9.4, 7.3, and 5.8% of the PM1 mass, respectively. Primary and secondary OC (POC and SOC, respectively) contributions also varied with the

  8. Optimal Parameter Selection for Support Vector Machine Based on Artificial Bee Colony Algorithm: A Case Study of Grid-Connected PV System Power Prediction

    Directory of Open Access Journals (Sweden)

    Xiang-ming Gao

    2017-01-01

    Full Text Available Predicting the output power of photovoltaic system with nonstationarity and randomness, an output power prediction model for grid-connected PV systems is proposed based on empirical mode decomposition (EMD and support vector machine (SVM optimized with an artificial bee colony (ABC algorithm. First, according to the weather forecast data sets on the prediction date, the time series data of output power on a similar day with 15-minute intervals are built. Second, the time series data of the output power are decomposed into a series of components, including some intrinsic mode components IMFn and a trend component Res, at different scales using EMD. The corresponding SVM prediction model is established for each IMF component and trend component, and the SVM model parameters are optimized with the artificial bee colony algorithm. Finally, the prediction results of each model are reconstructed, and the predicted values of the output power of the grid-connected PV system can be obtained. The prediction model is tested with actual data, and the results show that the power prediction model based on the EMD and ABC-SVM has a faster calculation speed and higher prediction accuracy than do the single SVM prediction model and the EMD-SVM prediction model without optimization.

  9. Optimal Parameter Selection for Support Vector Machine Based on Artificial Bee Colony Algorithm: A Case Study of Grid-Connected PV System Power Prediction.

    Science.gov (United States)

    Gao, Xiang-Ming; Yang, Shi-Feng; Pan, San-Bo

    2017-01-01

    Predicting the output power of photovoltaic system with nonstationarity and randomness, an output power prediction model for grid-connected PV systems is proposed based on empirical mode decomposition (EMD) and support vector machine (SVM) optimized with an artificial bee colony (ABC) algorithm. First, according to the weather forecast data sets on the prediction date, the time series data of output power on a similar day with 15-minute intervals are built. Second, the time series data of the output power are decomposed into a series of components, including some intrinsic mode components IMFn and a trend component Res, at different scales using EMD. The corresponding SVM prediction model is established for each IMF component and trend component, and the SVM model parameters are optimized with the artificial bee colony algorithm. Finally, the prediction results of each model are reconstructed, and the predicted values of the output power of the grid-connected PV system can be obtained. The prediction model is tested with actual data, and the results show that the power prediction model based on the EMD and ABC-SVM has a faster calculation speed and higher prediction accuracy than do the single SVM prediction model and the EMD-SVM prediction model without optimization.

  10. On-line measurement of mechanical, optical properties and roughness parameters

    Directory of Open Access Journals (Sweden)

    Hartman, H.

    2005-12-01

    Full Text Available On-line measurements become a central importance for the control of production line output. The target is to replace traditional single local destructive quality checks by a continuous survey of the product properties. Other traditional like pyrometric temperature measurements suffer of well-known but non-soluble weakness points. New methods need the unambiguous correlation with the results of traditional testing to be representative for valid proof standards.EKO Stahl GmbH introduces several methods of on-line measurements focused actually on temperature measurement means of FTIR-Spectrometer, prediction of the mechanical properties of steel strips using the information of residual magnetization after a magnetization pulse and optical roughness measurements. The correlation between the results of the new methods and the classical proof processes has been established in a satisfactory manner.

    Las medidas on line van tomando una importancia central para el control de la calidad de la producción . El objetivo es reemplazar las pruebas destructivas puntuales tradicionales por un control continuo de las características del producto. Otros métodos tradicionales, como la medida de la temperatura con pirómetros, adolecen de conocidos pero insolubles puntos débiles. Los nuevos métodos necesitan la correlación inequívoca con los resultados de los métodos corrientes clásicos para obtener la autoridad de un estándar de prueba. La EKO Stahl GmbH ha introducido varios métodos de medidas on line y actualmente concentrados en la medida de la temperatura con espectrómetro FTIR, predicción de las características mecánicas usando la información del magnetismo residual, a partir de un impulso magnético inicial así como la medida óptica de la rugosidad. La correlación entre los resultados de los nuevos métodos y los métodos clásicos ha quedado establecida de manera satisfactoria.

  11. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    International Nuclear Information System (INIS)

    Malinina, A. A.; Malinin, A. N.

    2013-01-01

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10 −14 m 3 /s for a reduced electric field of E/N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λ max = 502 nm) was observed in this experiment

  12. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    Science.gov (United States)

    Malinina, A. A.; Malinin, A. N.

    2013-12-01

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10-14 m3/s for a reduced electric field of E/ N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λmax = 502 nm) was observed in this experiment.

  13. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

    Energy Technology Data Exchange (ETDEWEB)

    Malinina, A. A., E-mail: alexandr_malinin@rambler.ru; Malinin, A. N. [Uzhhorod National University (Ukraine)

    2013-12-15

    Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10{sup −14} m{sup 3}/s for a reduced electric field of E/N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λ{sub max} = 502 nm) was observed in this experiment.

  14. Research on dual-parameter optical fiber sensor based on thin-core fiber and spherical structure

    Science.gov (United States)

    Tong, Zhengrong; Wang, Xue; Zhang, Weihua; Xue, Lifang

    2018-04-01

    A novel dual-parameter optical fiber sensor is proposed and experimentally demonstrated. The proposed sensor is based on a fiber in-line Mach-Zehnder interferometer, which is fabricated by sandwiching a section of thin-core fiber between two spherical structures made of single-mode fibers. The transmission spectrum exhibits the response of the interference between the core and the different cladding modes. Due to the different wavelength shifts of the two selected dips, the simultaneous measurement of temperature and the surrounding refractive index can be achieved. The measured temperature sensitivities are 0.067 nm/°C and 0.050 nm/°C, and the refractive index sensitivities are  -119.9 nm/RIU and  -69.71 nm/RIU, respectively. In addition, the compact size, simple fabrication and cost-effectiveness of the fiber sensor are also advantages.

  15. Validation of Cloud Optical Parameters from Passive Remote Sensing in the Arctic by using the Aircraft Measurements

    Science.gov (United States)

    Chen, H.; Schmidt, S.; Coddington, O.; Wind, G.; Bucholtz, A.; Segal-Rosenhaimer, M.; LeBlanc, S. E.

    2017-12-01

    Cloud Optical Parameters (COPs: e.g., cloud optical thickness and cloud effective radius) and surface albedo are the most important inputs for determining the Cloud Radiative Effect (CRE) at the surface. In the Arctic, the COPs derived from passive remote sensing such as from the Moderate Resolution Imaging Spectroradiometer (MODIS) are difficult to obtain with adequate accuracy owing mainly to insufficient knowledge about the snow/ice surface, but also because of the low solar zenith angle. This study aims to validate COPs derived from passive remote sensing in the Arctic by using aircraft measurements collected during two field campaigns based in Fairbanks, Alaska. During both experiments, ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) and ARISE (Arctic Radiation-IceBridge Sea and Ice Experiment), the Solar Spectral Flux Radiometer (SSFR) measured upwelling and downwelling shortwave spectral irradiances, which can be used to derive surface and cloud albedo, as well as the irradiance transmitted by clouds. We assess the variability of the Arctic sea ice/snow surfaces albedo through these aircraft measurements and incorporate this variability into cloud retrievals for SSFR. We then compare COPs as derived from SSFR and MODIS for all suitable aircraft underpasses of the satellites. Finally, the sensitivities of the COPs to surface albedo and solar zenith angle are investigated.

  16. Retrieval of Optical Parameters From Seawifs Observations Over The Pomme Area (north-est Atlantic): Biogeochemical Applications

    Science.gov (United States)

    Loisel, H.; Nicolas, J.-M.; Merien, D.; Claustre, H.; Sciandra, A.; Becu, G.; Deschamps, P.-Y.

    Since the success of the first ocean color instrument, the Coastal Zone Color Sen- sor (CZCS), the interpretation of ocean color in terms of phytoplankton pigment (the chlorophyll, Chl) is now well recognized. The chlorophyll data, as detected from space, are now currently used to constraint oceanic biological models. New gener- ation of biological models now integrate explicitly 2 or more species of plankton, as well as dissolved organic and particulate matter, DOC and POC, respectively. The as- sessment of such information from the Sea-viewing Wide Field-of-view Sensor and inverse modeling will be discussed. In the frame of the POMME (Programme Océan Multidisciplinaire Méso-Echelle) project we will present the seasonal variability of the absorption, a, the backscattering, bb, and the scattering, b, coefficients as retrieved from SeaWiFS observations over the POMME area. These optical parameters will be compared with in situ measurements made during winter, spring and summer 2001, and biological information derived from these optical properties retrieved at different wavelengths will be presented.

  17. Information content in spectral dependencies of optical unit volume parameters under action of He-Ne laser on blood

    Science.gov (United States)

    Khairullina, Alphiya Y.; Oleinik, Tatiana V.

    1995-01-01

    Our previous works concerned with the development of methods for studying blood and action of low-intensity laser radiation on blood and erythrocyte suspensions had shown the light- scattering methods gave a large body of information on a medium studied due to the methodological relationship between irradiation processes and techniques for investigations. Detail analysis of spectral diffuse reflectivities and transmissivities of optically thick blood layers, spectral absorptivities calculated on this basis over 600 - 900 nm, by using different approximations, for a pathological state owing to hypoxia testifies to the optical significance of not only hemoglobin derivatives but also products of hemoglobin decomposition. Laser action on blood is specific and related to an initial state of blood absorption due to different composition of chromoproteids. This work gives the interpretation of spectral observations. Analysis of spectral dependencies of the exinction coefficient e, mean cosine m of phase function, and parameter Q equals (epsilon) (1-(mu) )H/(lambda) (H - hematocrit) testifies to decreasing the relative index of refraction of erythrocytes and to morphological changes during laser action under pathology owing to hypoxia. The possibility to obtain physical and chemical information on the state of blood under laser action in vivo is shown to be based on the method proposed by us for calculating multilayered structures modeling human organs and on the technical implementation of this method.

  18. Investigation of optical band gap and device parameters of rubrene thin film prepared using spin coating technique

    International Nuclear Information System (INIS)

    Tuğluoğlu, Nihat; Barış, Behzad; Gürel, Hatice; Karadeniz, Serdar; Yüksel, Ömer Faruk

    2014-01-01

    Highlights: • Thin film of rubrene has been deposited by spin coating technique. • The band gap properties of the film were investigated in the range 200–700 nm. • The analysis of the absorption coefficient revealed indirect allowed transition. • The parameters such as barrier height and ideality factor were determined. -- Abstract: Rubrene thin film has been deposited by spin coating technique. The optical band gap properties of rubrene thin film have been investigated in the spectral range 200–700 nm. The results of the absorption coefficient (α) were analyzed in order to determine the optical band gap and Urbach energy of the film. The absorption spectra recorded in the UV–vis region shows two peaks at 250 nm and 300 nm. The analysis of the spectral behavior of the absorption coefficient (α) in the absorption region revealed indirect allowed transition with corresponding energy 2.31 eV. The value of Urbach energy (E U ) was determined to be 1.169 eV. The current–voltage (I–V) characteristics and electrical conduction properties of rubrene/n-Si device fabricated by spin coating method have also been investigated. The I–V characteristic in dark was showed the rectification effect due to the formation of Schottky barrier at rubrene/silicon interface. From analyzing the I-V measurement for the device, the basic device parameters such as barrier height, ideality factor and series resistance were determined. At the low-voltage region, the current conduction in Au/rubrene/n-Si device is ohmic type. The charge transport phenomenon appears to be space charge limited current (SCLC) at higher-voltage regions

  19. Investigation of optical band gap and device parameters of rubrene thin film prepared using spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Tuğluoğlu, Nihat, E-mail: tugluo@gmail.com [Department of Technology, Sarayköy Nuclear Research and Training Center, 06983 Saray, Ankara (Turkey); Barış, Behzad; Gürel, Hatice [Department of Physics, Faculty of Arts and Sciences, Giresun University, Gazipaşa Campus, Giresun 28100 (Turkey); Karadeniz, Serdar [Department of Technology, Sarayköy Nuclear Research and Training Center, 06983 Saray, Ankara (Turkey); Yüksel, Ömer Faruk [Department of Physics, Faculty of Science, Selçuk University, Campus Konya 42075 (Turkey)

    2014-01-05

    Highlights: • Thin film of rubrene has been deposited by spin coating technique. • The band gap properties of the film were investigated in the range 200–700 nm. • The analysis of the absorption coefficient revealed indirect allowed transition. • The parameters such as barrier height and ideality factor were determined. -- Abstract: Rubrene thin film has been deposited by spin coating technique. The optical band gap properties of rubrene thin film have been investigated in the spectral range 200–700 nm. The results of the absorption coefficient (α) were analyzed in order to determine the optical band gap and Urbach energy of the film. The absorption spectra recorded in the UV–vis region shows two peaks at 250 nm and 300 nm. The analysis of the spectral behavior of the absorption coefficient (α) in the absorption region revealed indirect allowed transition with corresponding energy 2.31 eV. The value of Urbach energy (E{sub U}) was determined to be 1.169 eV. The current–voltage (I–V) characteristics and electrical conduction properties of rubrene/n-Si device fabricated by spin coating method have also been investigated. The I–V characteristic in dark was showed the rectification effect due to the formation of Schottky barrier at rubrene/silicon interface. From analyzing the I-V measurement for the device, the basic device parameters such as barrier height, ideality factor and series resistance were determined. At the low-voltage region, the current conduction in Au/rubrene/n-Si device is ohmic type. The charge transport phenomenon appears to be space charge limited current (SCLC) at higher-voltage regions.

  20. Glaucoma Diagnostic Capabilities of Foveal Avascular Zone Parameters Using Optical Coherence Tomography Angiography According to Visual Field Defect Location.

    Science.gov (United States)

    Kwon, Junki; Choi, Jaewan; Shin, Joong Won; Lee, Jiyun; Kook, Michael S

    2017-12-01

    To assess the diagnostic ability of foveal avascular zone (FAZ) parameters to discriminate glaucomatous eyes with visual field defects (VFDs) in different locations (central vs. peripheral) from normal eyes. Totally, 125 participants were separated into 3 groups: normal (n=45), glaucoma with peripheral VFD (PVFD, n=45), and glaucoma with central VFD (CVFD, n=35). The FAZ area, perimeter, and circularity and parafoveal vessel density were calculated from optical coherence tomography angiography images. The diagnostic ability of the FAZ parameters and other structural parameters was determined according to glaucomatous VFD location. Associations between the FAZ parameters and central visual function were evaluated. A larger FAZ area and longer FAZ perimeter were observed in the CVFD group than in the PVFD and normal groups. The FAZ area, perimeter, and circularity were better in differentiating glaucomatous eyes with CVFDs from normal eyes [areas under the receiver operating characteristic curves (AUC), 0.78 to 0.88] than in differentiating PVFDs from normal eyes (AUC, 0.51 to 0.64). The FAZ perimeter had a similar AUC value to the circumpapillary retinal nerve fiber layer and macular ganglion cell-inner plexiform layer thickness for differentiating eyes with CVFDs from normal eyes (all P>0.05, the DeLong test). The FAZ area was significantly correlated with central visual function (β=-112.7, P=0.035, multivariate linear regression). The FAZ perimeter had good diagnostic capability in differentiating glaucomatous eyes with CVFDs from normal eyes, and may be a potential diagnostic biomarker for detecting glaucomatous patients with CVFDs.

  1. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  2. Optical assessment of colored dissolved organic matter and its related parameters in dynamic coastal water systems

    Science.gov (United States)

    Shanmugam, Palanisamy; Varunan, Theenathayalan; Nagendra Jaiganesh, S. N.; Sahay, Arvind; Chauhan, Prakash

    2016-06-01

    Prediction of the curve of the absorption coefficient of colored dissolved organic matter (CDOM) and differentiation between marine and terrestrially derived CDOM pools in coastal environments are hampered by a high degree of variability in the composition and concentration of CDOM, uncertainties in retrieved remote sensing reflectance and the weak signal-to-noise ratio of space-borne instruments. In the present study, a hybrid model is presented along with empirical methods to remotely determine the amount and type of CDOM in coastal and inland water environments. A large set of in-situ data collected on several oceanographic cruises and field campaigns from different regional waters was used to develop empirical methods for studying the distribution and dynamics of CDOM, dissolved organic carbon (DOC) and salinity. Our validation analyses demonstrated that the hybrid model is a better descriptor of CDOM absorption spectra compared to the existing models. Additional spectral slope parameters included in the present model to differentiate between terrestrially derived and marine CDOM pools make a substantial improvement over those existing models. Empirical algorithms to derive CDOM, DOC and salinity from remote sensing reflectance data demonstrated success in retrieval of these products with significantly low mean relative percent differences from large in-situ measurements. The performance of these algorithms was further assessed using three hyperspectral HICO images acquired simultaneously with our field measurements in productive coastal and lagoon waters on the southeast part of India. The validation match-ups of CDOM and salinity showed good agreement between HICO retrievals and field observations. Further analyses of these data showed significant temporal changes in CDOM and phytoplankton absorption coefficients with a distinct phase shift between these two products. Healthy phytoplankton cells and macrophytes were recognized to directly contribute to the

  3. Effects of Various Parameters on Structural and Optical Properties of CBD-Grown ZnS Thin Films: A Review

    Science.gov (United States)

    Sinha, Tarkeshwar; Lilhare, Devjyoti; Khare, Ayush

    2018-02-01

    Zinc sulfide (ZnS) thin films deposited by chemical bath deposition (CBD) technique have proved their capability in a wide area of applications including electroluminescent and display devices, solar cells, sensors, and field emitters. These semiconducting thin films have attracted a much attention from the scientific community for industrial and research purposes. In this article, we provide a comprehensive review on the effect of various parameters on various properties of CBD-grown ZnS films. In the first part, we discuss the historical background of ZnS, its basic properties, and the advantages of the CBD technique. Detailed discussions on the film growth, structural and optical properties of ZnS thin films affected by various parameters, such as bath temperature and concentration, deposition time, stirring speed, complexing agents, pH value, humidity in the environment, and annealing conditions, are also presented. In later sections, brief information about the recent studies and findings is also added to explore the scope of research work in this field.

  4. Investigation of some critical parameters of buffer conditions for the development of quantum dots-based optical sensors

    International Nuclear Information System (INIS)

    Yuan Jipei; Guo Weiwei; Wang Erkang

    2008-01-01

    The unique surface-sensitive properties make quantum dots (QDs) great potential in the development of sensors for various analytes. However, quantum dots are not only sensitive to a certain analyte, but also to the surrounding conditions. The controlled response to analyte may be the first step in the designing of functional quantum dots sensors. In this study, taking the quenching effect of benzoquinone (BQ) on CdTe QDs as model, several critical parameters of buffer solution conditions with potential effect on the sensors were investigated. The pH value and the concentration of sodium citrate in the buffer solution critically influenced the quenching effects of BQ. Dozens folds elevation of the quenching extents were observed with the increase of concentrations of H + and sodium citrate, and the quenching mechanisms were also fundamentally different with the changes of the surrounding buffer solutions. The quenching models were proposed and analyzed at different buffer conditions. Taking pH values for example, QDs quenching obeyed the sphere of effective quenching model with the sphere radii of 8.29 nm at pH 8.0, the linear Stern-Volmer equation with Stern-Volmer constant of 2.0 x 10 3 mol -1 L at pH 7.0, and the two binding site static quenching model at basic conditions. The elucidation of parameters for assay performance was important in the development of QDs-based optical sensors

  5. Determination of the depth-resolved Stokes parameters of light backscattered from turbid media by use of polarization-sensitive optical coherence tomography

    International Nuclear Information System (INIS)

    Boer, J.F. de; Milner, T.E.; Nelson, J.S.

    1999-01-01

    Polarization-sensitive optical coherence tomography (PS-OCT) was used to characterize completely the polarization state of light backscattered from turbid media. Using a low-coherence light source, one can determine the Stokes parameters of backscattered light as a function of optical path in turbid media. To demonstrate the application of this technique we determined the birefringence and the optical axis in fibrous tissue (rodent muscle) and in vivo rodent skin. PS-OCT has potentially useful applications in biomedical optics by imaging simultaneously the structural properties of turbid biological materials and their effects on the polarization state of backscattered light. This method may also find applications in material science for investigation of polarization properties (e.g., birefringence) in opaque media such as ceramics and crystals. copyright 1999 Optical Society of America

  6. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  7. Aerosol optical properties in the southeastern United States in summer – Part 2: Sensitivity of aerosol optical depth to relative humidity and aerosol parameters

    Directory of Open Access Journals (Sweden)

    C. A. Brock

    2016-04-01

    Full Text Available Aircraft observations of meteorological, trace gas, and aerosol properties were made between May and September 2013 in the southeastern United States (US. Regionally representative aggregate vertical profiles of median and interdecile ranges of the measured parameters were constructed from 37 individual aircraft profiles made in the afternoon when a well-mixed boundary layer with typical fair-weather cumulus was present (Wagner et al., 2015. We use these 0–4 km aggregate profiles and a simple model to calculate the sensitivity of aerosol optical depth (AOD to changes in dry aerosol mass, relative humidity, mixed-layer height, the central diameter and width of the particle size distribution, hygroscopicity, and dry and wet refractive index, while holding the other parameters constant. The calculated sensitivity is a result of both the intrinsic sensitivity and the observed range of variation in these parameters. These observationally based sensitivity studies indicate that the relationship between AOD and dry aerosol mass in these conditions in the southeastern US can be highly variable and is especially sensitive to relative humidity (RH. For example, calculated AOD ranged from 0.137 to 0.305 as the RH was varied between the 10th and 90th percentile profiles with dry aerosol mass held constant. Calculated AOD was somewhat less sensitive to aerosol hygroscopicity, mean size, and geometric standard deviation, σg. However, some chemistry–climate models prescribe values of σg substantially larger than we or others observe, leading to potential high biases in model-calculated AOD of  ∼  25 %. Finally, AOD was least sensitive to observed variations in dry and wet aerosol refractive index and to changes in the height of the well-mixed surface layer. We expect these findings to be applicable to other moderately polluted and background continental air masses in which an accumulation mode between 0.1–0.5 µm diameter dominates

  8. PCB 136 Atropselectively Alters Morphometric and Functional Parameters of Neuronal Connectivity in Cultured Rat Hippocampal Neurons via Ryanodine Receptor-Dependent Mechanisms

    Science.gov (United States)

    Yang, Dongren; Kania-Korwel, Izabela; Ghogha, Atefeh; Chen, Hao; Stamou, Marianna; Bose, Diptiman D.; Pessah, Isaac N.; Lehmler, Hans-Joachim; Lein, Pamela J.

    2014-01-01

    We recently demonstrated that polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substitutions sensitize ryanodine receptors (RyRs), and this activity promotes Ca2+-dependent dendritic growth in cultured neurons. Many ortho-substituted congeners display axial chirality, and we previously reported that the chiral congener PCB 136 (2,2′,3,3′,6,6′-hexachlorobiphenyl) atropselectively sensitizes RyRs. Here, we test the hypothesis that PCB 136 atropisomers differentially alter dendritic growth and other parameters of neuronal connectivity influenced by RyR activity. (−)-PCB 136, which potently sensitizes RyRs, enhances dendritic growth in primary cultures of rat hippocampal neurons, whereas (+)-PCB 136, which lacks RyR activity, has no effect on dendritic growth. The dendrite-promoting activity of (−)-PCB 136 is observed at concentrations ranging from 0.1 to 100nM and is blocked by pharmacologic RyR antagonism. Neither atropisomer alters axonal growth or cell viability. Quantification of PCB 136 atropisomers in hippocampal cultures indicates that atropselective effects on dendritic growth are not due to differential partitioning of atropisomers into cultured cells. Imaging of hippocampal neurons loaded with Ca2+-sensitive dye demonstrates that (−)-PCB 136 but not (+)-PCB 136 increases the frequency of spontaneous Ca2+ oscillations. Similarly, (−)-PCB 136 but not (+)-PCB 136 increases the activity of hippocampal neurons plated on microelectrode arrays. These data support the hypothesis that atropselective effects on RyR activity translate into atropselective effects of PCB 136 atropisomers on neuronal connectivity, and suggest that the variable atropisomeric enrichment of chiral PCBs observed in the human population may be a significant determinant of individual susceptibility for adverse neurodevelopmental outcomes following PCB exposure. PMID:24385416

  9. Establishing the functional connectivity of the frontotemporal network in pre-attentive change detection with Transcranial Magnetic Stimulation and event-related optical signal.

    Science.gov (United States)

    Tse, Chun-Yu; Long-Yin, Yip; Lui, Troby Ka-Yan; Xiao, Xue-Zhen; Wang, Yang; Chu, Winnie Chiu Wing; Parks, Nathan Allen; Chan, Sandra Sau-Man; Neggers, Sebastiaan Franciscus Wijnandus

    2018-06-18

    Current theories of pre-attentive deviant detection postulate that before the Superior Temporal Cortex (STC) detects a change, the Inferior Frontal Cortex (IFC) engages in stimulus analysis, which is particularly critical for ambiguous deviations (e.g., deviant preceded by a short train of standards). These theories rest on the assumption that IFC and STC are functionally connected, which has only been supported by correlational brain imaging studies. We examined this functional connectivity assumption by applying Transcranial Magnetic Stimulation (TMS) to disrupt IFC function, while measuring the later STC mismatch response with the event-related optical signal (EROS). EROS can localize brain activity in both spatial and temporal dimensions via measurement of optical property changes associated with neuronal activity, and is inert to the electromagnetic interference produced by TMS. Specifically, the STC mismatch response at 120-180 ms elicited by a deviant preceded by a short standard train when IFC TMS was applied at 80 ms was compared with the STC mismatch responses in temporal control (TMS with 200 ms delay), spatial control (sham TMS at vertex), auditory control (TMS pulse noise only), and cognitive control (deviant preceded by a long standard train) conditions. The STC mismatch response to deviants preceded by the short train was abolished by TMS of the IFC at 80 ms, while the STC responses remained intact in all other control conditions. These results confirm the involvement of the IFC in the STC mismatch response and support a functional connection between IFC and STC. Copyright © 2018. Published by Elsevier Inc.

  10. Highly crystalline p-PbS thin films with tunable optical and hole transport parameters by chemical bath deposition

    International Nuclear Information System (INIS)

    Bai, Rekha; Kumar, Dinesh; Chaudhary, Sujeet; Pandya, Dinesh K.

    2017-01-01

    Lead sulfide (PbS) thin films, consisting of well faceted (up to 400 nm) cubic-nanocrystals and possessing significantly improved opto-electronic parameters essential for photovoltaic applications, are grown by utilizing chemical bath deposition (CBD) technique with bath concentrations of 10–200 mM. X-ray diffraction (XRD) and Raman studies confirm the highly crystalline and pure phase of PbS. FESEM and HRTEM studies show that all the films possess uniform and compact (111) oriented nanocubic morphology. Bath concentration change provides tunability of nanocube size from 100 to 400 nm and the direct optical band gap from 1.50 to 0.94 eV. The PbS films exhibit p-type semiconducting behavior with hitherto unreported concurrent highest mobility of 29.3 cm"2V"−"1s"−"1 and high carrier concentration of ∼10"1"8 cm"−"3 with the lowest room temperature resistivity of 0.26 Ω–cm. The 25 mM and 10 mM films show significant surface plasmon absorption in 1200–2400 nm range making them suitable as efficient infrared absorbers in excitonic and multi-junction solar cells.

  11. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    Science.gov (United States)

    Malinina, A. A.; Malinin, A. N.

    2015-03-01

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λmax = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/ N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10-15 m3/s.

  12. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    Energy Technology Data Exchange (ETDEWEB)

    Malinina, A. A., E-mail: alexandr-malinin@rambler.ru; Malinin, A. N. [Uzhhorod National University (Ukraine)

    2015-03-15

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ{sub max} = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10{sup −15} m{sup 3}/s.

  13. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    International Nuclear Information System (INIS)

    Malinina, A. A.; Malinin, A. N.

    2015-01-01

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ max = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10 −15 m 3 /s

  14. Electronic polarizability, optical basicity and interaction parameter for Nd{sub 2}O{sub 3} doped lithium-zinc-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Algradee, M.A.; Sultan, M.; Samir, O.M.; Alwany, A.E.B. [Ibb University, Department of Physics, Faculty of Science, Ibb (Yemen)

    2017-08-15

    The Nd{sup 3+}-doped lithium-zinc-phosphate glasses were prepared by means of conventional melt quenching method. X-ray diffraction results confirmed the glassy nature of the studied glasses. The physical parameters such as the density, molar volume, ion concentration, polaron radius, inter-ionic distance, field strength and oxygen packing density were calculated using different formulae. The transmittance and reflectance spectra of glasses were recorded in the wavelength range 190-1200 nm. The values of optical band gap and Urbach energy were determined based on Mott-Davis model. The refractive indices for the studied glasses were evaluated from optical band gap values using different methods. The average electronic polarizability of the oxide ions, optical basicity and an interaction parameter were investigated from the calculated values of the refractive index and the optical band gap for the studied glasses. The variations in the different physical and optical properties of glasses with Nd{sub 2}O{sub 3} content were discussed in terms of different parameters such as non-bridging oxygen and different concentrations of Nd cation in glass system. (orig.)

  15. Large Electro-Optic Kerr-Effect in Ionic Liquid Crystals: Connecting Features of Liquid Crystals and Polyelectrolytes.

    Science.gov (United States)

    Schlick, Michael Christian; Kapernaum, Nadia; Neidhardt, Manuel; Wöhrle, Tobias; Stöckl, Yannick; Laschat, Sabine; Gießelmann, Frank

    2018-06-06

    The electro-optic Kerr effect in the isotropic phase of two ionic liquid crystals (ILCs) is investigated and compared to the Kerr effect in non-ionic liquid crystals (LCs) with same phase sequences, namely direct isotropic to hexagonal columnar transitions and direct isotropic to smectic-A transitions. Up to electric field amplitudes of some 106 V m-1, the optical birefringence induced in the isotropic phases follows Kerr's law and strongly increases when the temperature approaches the transition temperature into the particular liquid crystalline phase. Close to the transition, maximum Kerr constants in the order of 10-11 m V-2 are found, which are more than ten times higher than the Kerr constant of nitrobenzene, a strongly dipolar fluid with a huge Kerr effect applied in optical shutters and phase modulators. In comparison to their non-ionic LC counterparts the Kerr effect in ILCs is found to be enhanced in magnitude, but slowed-down in speed, showing rise times in the order of ten milliseconds. These remarkable differences are attributed to the presence of counterion polarization well-known from complex ionic fluids such as polyelectrolytes or ionic micellar solutions. ILCs thus combine the Kerr effect features of liquid crystals and complex ionic fluids. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. HIGH-REDSHIFT DUST OBSCURED GALAXIES: A MORPHOLOGY-SPECTRAL ENERGY DISTRIBUTION CONNECTION REVEALED BY KECK ADAPTIVE OPTICS

    International Nuclear Information System (INIS)

    Melbourne, J.; Matthews, K.; Soifer, B. T.

    2009-01-01

    A simple optical to mid-IR color selection, R - [24]>14, i.e., f ν (24 μm)/f ν (R) ∼> 1000, identifies highly dust obscured galaxies (DOGs) with typical redshifts of z ∼ 2 ± 0.5. Extreme mid-IR luminosities (L IR > 10 12-14 ) suggest that DOGs are powered by a combination of active galactic nuclei (AGNs) and star formation, possibly driven by mergers. In an effort to compare their photometric properties with their rest-frame optical morphologies, we obtained high-spatial resolution (0.''05-0.''1) Keck Adaptive Optics K'-band images of 15 DOGs. The images reveal a wide range of morphologies, including small exponential disks (eight of 15), small ellipticals (four of 15), and unresolved sources (two of 15). One particularly diffuse source could not be classified because of low signal-to-noise ratio. We find a statistically significant correlation between galaxy concentration and mid-IR luminosity, with the most luminous DOGs exhibiting higher concentration and smaller physical size. DOGs with high concentration also tend to have spectral energy distributions (SEDs) suggestive of AGN activity. Thus, central AGN light may be biasing the morphologies of the more luminous DOGs to higher concentration. Conversely, more diffuse DOGs tend to show an SED shape suggestive of star formation. Two of 15 in the sample show multiple resolved components with separations of ∼1 kpc, circumstantial evidence for ongoing mergers.

  17. Performance evaluation of modulation and multiple access schemes in ultraviolet optical wireless connections for two atmosphere thickness cases.

    Science.gov (United States)

    Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris

    2016-08-01

    The exploitation of optical wireless communication channels in a non-line-of-sight regime is studied for point-to-point and networking configurations considering the use of light-emitting diodes. Two environments with different scattering center densities are considered, assuming operation at 265 nm. The bit error rate performance of both pulsed and multicarrier modulation schemes is examined, using numerical approaches. In the networking scenario, a central node only receives data, one node transmits useful data, and the rest of them act as interferers. The performance of the desirable node's transmissions is evaluated. The access to the medium is controlled by a code division multiple access scheme.

  18. Modeling radiative transfer in tropical rainforest canopies: sensitivity of simulated albedo to canopy architectural and optical parameters

    Directory of Open Access Journals (Sweden)

    Sílvia N. M. Yanagi

    2011-12-01

    Full Text Available This study evaluates the sensitivity of the surface albedo simulated by the Integrated Biosphere Simulator (IBIS to a set of Amazonian tropical rainforest canopy architectural and optical parameters. The parameters tested in this study are the orientation and reflectance of the leaves of upper and lower canopies in the visible (VIS and near-infrared (NIR spectral bands. The results are evaluated against albedo measurements taken above the K34 site at the INPA (Instituto Nacional de Pesquisas da Amazônia Cuieiras Biological Reserve. The sensitivity analysis indicates a strong response to the upper canopy leaves orientation (x up and to the reflectivity in the near-infrared spectral band (rNIR,up, a smaller sensitivity to the reflectivity in the visible spectral band (rVIS,up and no sensitivity at all to the lower canopy parameters, which is consistent with the canopy structure. The combination of parameters that minimized the Root Mean Square Error and mean relative error are Xup = 0.86, rVIS,up = 0.062 and rNIR,up = 0.275. The parameterizations performed resulted in successful simulations of tropical rainforest albedo by IBIS, indicating its potential to simulate the canopy radiative transfer for narrow spectral bands and permitting close comparison with remote sensing products.Este estudo avalia a sensibilidade do albedo da superfície pelo Simulador Integrado da Biosfera (IBIS a um conjunto de parâmetros que representam algumas propriedades arquitetônicas e óticas do dossel da floresta tropical Amazônica. Os parâmetros testados neste estudo são a orientação e refletância das folhas do dossel superior e inferior nas bandas espectrais do visível (VIS e infravermelho próximo (NIR. Os resultados são avaliados contra observações feitas no sítio K34 pertencente ao Instituto Nacional de Pesquisas da Amazônia (INPA na Reserva Biológica de Cuieiras. A análise de sensibilidade indica uma forte resposta aos parâmetros de orienta

  19. Fiber optics: A brief introduction

    International Nuclear Information System (INIS)

    Gruchalla, M.E.

    1989-01-01

    A basic introduction into the principles of fiber optics is presented. A review of both the underlying physical principles and the individual elements of typical fiber-optic systems are presented. The optical phenomenon of total internal reflection is reviewed. The basic construction of the optical fiber is presented. Both step-index and graded-index fiber designs are reviewed. Multimode and single-mode fiber constructions are considered and typical performance parameters given. Typical optical-fiber bandwidth and loss characteristics are compared to various common coaxial cables, waveguides, and air transmission. The constructions of optical-fiber cables are reviewed. Both loose-tube and tightly-buffered designs are considered. Several optical connection approaches are presented. Photographs of several representative optical connectors are included. Light Emitting Diode and Laser Diode emitters for fiber-optic applications are reviewed, and some advantages and shortcomings of each are considered. The phenomenon of modal noise is briefly explained. Both PIN and Avalanche photodetectors are reviewed and their performance parameters compared. Methods of data transmission over optical fiber are introduced. Principles of Wavelength, Frequency, and Time Division Multiplexing are briefly presented. The technology of fiber-optic sensors is briefly reviewed with basic principles introduced. The performance of a fiber-optic strain sensor is included as a practical example. 7 refs., 10 figs

  20. Effect of conjugation length on nonlinear optical parameters of anthraquinone dyes investigated using He-Ne laser operating in CW mode

    Science.gov (United States)

    Pramodini, S.; Poornesh, P.

    2014-10-01

    We report the studies on third-order optical nonlinearity and optical limiting of anthraquinone dyes. Z-scan technique was employed to evaluate the nonlinear parameters such as nonlinear absorption coefficient βeff and nonlinear index of refraction n2. Continuous wave He-Ne laser was used as the source of excitation. The estimated values of βeff, n2 and χ(3) are of the order of 10-3 cm/W, 10-5 esu and 10-7 esu respectively. The presence of donor and acceptor groups in the structure results in increase in conjugation length. This resulted in the enhancement of nonlinear optical parameters values of the dye. Multiple diffraction rings were observed when the samples were exposed to laser beam due to thermal lensing. Dyes exhibited good optical limiting behavior under the experimental conditions. The results indicate that the dyes investigated here are materialise as candidates for photonics device applications such as optical power limiters.

  1. Controllable generation and propagation of ultraslow optical solitons via parameters management in a five-level hyper inverted-Y atomic system

    International Nuclear Information System (INIS)

    Si Liugang; Lue Xinyou; Li Jiahua; Hao Xiangying; Wang Meng

    2009-01-01

    The dynamics of generation and propagation of ultraslow optical solitons in a lifetime-broadened five-level hyper inverted-Y atomic system are investigated. Due to the novel absorption and dispersion properties of this system which provide the necessary ingredients for making the probe field propagate nearly transparent in three regimes, the generation of bright or dark optical solitons can be controlled with parameters management by actively manipulating the dispersion, the nonlinearity and the gain (absorption coefficient) via adjusting the corresponding one-, two- and three-photon detunings and the Rabi frequencies.

  2. Influence of deposition parameters on the optical and structural properties of TiO/sub 2/ films produced by reactive dc plasmatron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Schiller, S; Beister, G; Sieber, W; Schirmer, G; Hacker, E

    1981-09-11

    We investigated the variations in the structure and optical properties of TiO/sub 2/ films produced by reactive d.c. plasmatron sputtering with the most important deposition parameters. Over a wide range, the phase composition (ratio of rutile to anatase) and the grain size of the TiO/sub 2/ films can be influenced in a controlled manner by variations in the substrate temperature and the oxygen partial pressure. Because of their high refractive index and low light-scattering losses, plasmatron-sputtered TiO/sub 2/ films are of great interest in the field of optical interference coatings, e.g. for dielectric multilayer stacks.

  3. Microglomerular Synaptic Complexes in the Sky-Compass Network of the Honeybee Connect Parallel Pathways from the Anterior Optic Tubercle to the Central Complex.

    Science.gov (United States)

    Held, Martina; Berz, Annuska; Hensgen, Ronja; Muenz, Thomas S; Scholl, Christina; Rössler, Wolfgang; Homberg, Uwe; Pfeiffer, Keram

    2016-01-01

    While the ability of honeybees to navigate relying on sky-compass information has been investigated in a large number of behavioral studies, the underlying neuronal system has so far received less attention. The sky-compass pathway has recently been described from its input region, the dorsal rim area (DRA) of the compound eye, to the anterior optic tubercle (AOTU). The aim of this study is to reveal the connection from the AOTU to the central complex (CX). For this purpose, we investigated the anatomy of large microglomerular synaptic complexes in the medial and lateral bulbs (MBUs/LBUs) of the lateral complex (LX). The synaptic complexes are formed by tubercle-lateral accessory lobe neuron 1 (TuLAL1) neurons of the AOTU and GABAergic tangential neurons of the central body's (CB) lower division (TL neurons). Both TuLAL1 and TL neurons strongly resemble neurons forming these complexes in other insect species. We further investigated the ultrastructure of these synaptic complexes using transmission electron microscopy. We found that single large presynaptic terminals of TuLAL1 neurons enclose many small profiles (SPs) of TL neurons. The synaptic connections between these neurons are established by two types of synapses: divergent dyads and divergent tetrads. Our data support the assumption that these complexes are a highly conserved feature in the insect brain and play an important role in reliable signal transmission within the sky-compass pathway.

  4. CDOM Optical Properties and Connectivity in the Western Gulf of Alaska, the Unimak Pass and the Southeastern Bering Sea in the Spring During a Cold Year

    Science.gov (United States)

    D'Sa, E. J.; Goes, J. I.; Mouw, C. B.

    2016-02-01

    Flow through the Aleutian Passes connects the North Pacific to the Bering Sea with the Unimak Pass forming an important conduit for the flow of Gulf of Alaska water to the southeastern Bering shelf. While the biophysical properties have been studied for this region, little is known about the dissolved organic matter (DOM) and its optically active chromophoric component (CDOM) which play key roles in ocean color and several biogeochemical and photochemical processes. Dissolved organic carbon (DOC), and CDOM absorption and fluorescence properties were measured at locations in the western Gulf of Alaska, Unimak Pass and the southeastern Bering Sea in spring 2012, a relatively cold year as indicated by hydrographic field and satellite sea surface temperature data. DOC concentrations were on average higher in the western Gulf of Alaska (112.21 ± 20.05 µM) and Unimak Pass (106.14 ± 16.10 µM), than the southeastern Bering Sea shelf (73.28 ± 11.71 µM) suggesting Gulf of Alaska shelf water to be an important source of DOM to the eastern Bering Sea. Overall, CDOM absorption was relatively low while parallel factor (PARAFAC) analysis of DOM fluorescence identified two humic-like (terrestrial and marine) and one protein-like (tryptophan-like) component in the DOM pool. Relationships between the DOM optical properties and the physical regime will be further examined in this study.

  5. Altered Functional Connectivity Following an Inflammatory White Matter Injury in the Newborn Rat: A High Spatial and Temporal Resolution Intrinsic Optical Imaging Study

    Directory of Open Access Journals (Sweden)

    Edgar Guevara

    2017-07-01

    Full Text Available Very preterm newborns have an increased risk of developing an inflammatory cerebral white matter injury that may lead to severe neuro-cognitive impairment. In this study we performed functional connectivity (fc analysis using resting-state optical imaging of intrinsic signals (rs-OIS to assess the impact of inflammation on resting-state networks (RSN in a pre-clinical model of perinatal inflammatory brain injury. Lipopolysaccharide (LPS or saline injections were administered in postnatal day (P3 rat pups and optical imaging of intrinsic signals were obtained 3 weeks later. (rs-OIS fc seed-based analysis including spatial extent were performed. A support vector machine (SVM was then used to classify rat pups in two categories using fc measures and an artificial neural network (ANN was implemented to predict lesion size from those same fc measures. A significant decrease in the spatial extent of fc statistical maps was observed in the injured group, across contrasts and seeds (*p = 0.0452 for HbO2 and **p = 0.0036 for HbR. Both machine learning techniques were applied successfully, yielding 92% accuracy in group classification and a significant correlation r = 0.9431 in fractional lesion volume prediction (**p = 0.0020. Our results suggest that fc is altered in the injured newborn brain, showing the long-standing effect of inflammation.

  6. Optimisation of the parameters of a pump chamber for solid-state lasers with diode pumping by the optical boiler method

    Energy Technology Data Exchange (ETDEWEB)

    Kiyko, V V; Kislov, V I; Ofitserov, E N; Suzdal' tsev, A G [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2015-06-30

    A pump chamber of the optical boiler type for solid-state lasers with transverse laser diode pumping is studied theoretically and experimentally. The pump chamber parameters are optimised using the geometrical optics approximation for the pump radiation. According to calculations, the integral absorption coefficient of the active element at a wavelength of 808 nm is 0.75 – 0.8 and the relative inhomogeneity of the pump radiation distribution over the active element volume is 17% – 19%. The developed pump chamber was used in a Nd:YAG laser. The maximum cw output power at a wavelength of 1064 nm was ∼480 W at the optical efficiency up to 19.6%, which agrees with theoretical estimates. (lasers)

  7. Sex- and habitat-specific movement of an omnivorous semi-terrestrial crab controls habitat connectivity and subsidies: a multi-parameter approach.

    Science.gov (United States)

    Hübner, Lena; Pennings, Steven C; Zimmer, Martin

    2015-08-01

    Distinct habitats are often linked through fluxes of matter and migration of organisms. In particular, intertidal ecotones are prone to being influenced from both the marine and the terrestrial realms, but whether or not small-scale migration for feeding, sheltering or reproducing is detectable may depend on the parameter studied. Within the ecotone of an upper saltmarsh in the United States, we investigated the sex-specific movement of the semi-terrestrial crab Armases cinereum using an approach of determining multiple measures of across-ecotone migration. To this end, we determined food preference, digestive abilities (enzyme activities), bacterial hindgut communities (genetic fingerprint), and the trophic position of Armases and potential food sources (stable isotopes) of males versus females of different sub-habitats, namely high saltmarsh and coastal forest. Daily observations showed that Armases moved frequently between high-intertidal (saltmarsh) and terrestrial (forest) habitats. Males were encountered more often in the forest habitat, whilst gravid females tended to be more abundant in the marsh habitat but moved more frequently. Food preference was driven by both sex and habitat. The needlerush Juncus was preferred over three other high-marsh detrital food sources, and the periwinkle Littoraria was the preferred prey of male (but not female) crabs from the forest habitats; both male and female crabs from marsh habitat preferred the fiddler crab Uca over three other prey items. In the field, the major food sources were clearly vegetal, but males have a higher trophic position than females. In contrast to food preference, isotope data excluded Uca and Littoraria as major food sources, except for males from the forest, and suggested that Armases consumes a mix of C4 and C3 plants along with animal prey. Digestive enzyme activities differed significantly between sexes and habitats and were higher in females and in marsh crabs. The bacterial hindgut community

  8. Development of a computerized system for the storage, retrieval and optimization of optical model parameters for nuclear data computations. Final report for IAEA technical contract No. 7408/RB/TC

    International Nuclear Information System (INIS)

    Avrigeanu, M.; Avrigeanu, V.

    1994-09-01

    A proposal for an optical potential parameter compilation format like-EXFOR system is presented, in total agreement with the structure of EXFOR. With respect to the primary RIPL objectives, an extended subroutine SYSPOT of the widely-used optical model code SCAT2, which is actually a library of global and regional optical potential parameter sets, could be well-suited. A version which allows the use of a great part of published potentials is also given. (Author) 1 Tab., 21 Refs

  9. Analysis of optical band-gap shift in impurity doped ZnO thin films by using nonparabolic conduction band parameters

    International Nuclear Information System (INIS)

    Kim, Won Mok; Kim, Jin Soo; Jeong, Jeung-hyun; Park, Jong-Keuk; Baik, Young-Jun; Seong, Tae-Yeon

    2013-01-01

    Polycrystalline ZnO thin films both undoped and doped with various types of impurities, which covered the wide carrier concentration range of 10 16 –10 21 cm −3 , were prepared by magnetron sputtering, and their optical-band gaps were investigated. The experimentally measured optical band-gap shifts were analyzed by taking into account the carrier density dependent effective mass determined by the first-order nonparabolicity approximation. It was shown that the measured shifts in optical band-gaps in ZnO films doped with cationic dopants, which mainly perturb the conduction band, could be well represented by theoretical estimation in which the band-gap widening due to the band-filling effect and the band-gap renormalization due to the many-body effect derived for a weakly interacting electron-gas model were combined and the carrier density dependent effective mass was incorporated. - Highlights: ► Optical band-gaps of polycrystalline ZnO thin films were analyzed. ► Experimental carrier concentration range covered from 10 16 to 10 21 cm −3 . ► Nonparabolic conduction band parameters were used in theoretical analysis. ► The band-filling and the band-gap renormalization effects were considered. ► The measured optical band-gap shifts corresponded well with the calculated ones

  10. Intrinsic optical signal imaging of the blood volume changes is sufficient for mapping the resting state functional connectivity in the rodent cortex

    Science.gov (United States)

    Kura, Sreekanth; Xie, Hongyu; Fu, Buyin; Ayata, Cenk; Boas, David A.; Sakadžić, Sava

    2018-06-01

    Objective. Resting state functional connectivity (RSFC) allows the study of functional organization in normal and diseased brain by measuring the spontaneous brain activity generated under resting conditions. Intrinsic optical signal imaging (IOSI) based on multiple illumination wavelengths has been used successfully to compute RSFC maps in animal studies. The IOSI setup complexity would be greatly reduced if only a single wavelength can be used to obtain comparable RSFC maps. Approach. We used anesthetized mice and performed various comparisons between the RSFC maps based on single wavelength as well as oxy-, deoxy- and total hemoglobin concentration changes. Main results. The RSFC maps based on IOSI at a single wavelength selected for sensitivity to the blood volume changes are quantitatively comparable to the RSFC maps based on oxy- and total hemoglobin concentration changes obtained by the more complex IOSI setups. Moreover, RSFC maps do not require CCD cameras with very high frame acquisition rates, since our results demonstrate that they can be computed from the data obtained at frame rates as low as 5 Hz. Significance. Our results will have general utility for guiding future RSFC studies based on IOSI and making decisions about the IOSI system designs.

  11. Dependence of Optical Properties of SEL-Deposited Silver Gallium Selenide Thin Films on the On-Line Growth Parameter: Annealing Duration

    International Nuclear Information System (INIS)

    Bhuiyan, M.R.A.; Firoz Hasan, S.M.

    2005-01-01

    Silver gallium selenide (AGS) composite thin films were formed onto ultrasonically and chemically cleaned glass substrates by successive on-line thermal evaporation of individual elements and post-deposition annealing at 300 0 C for various durations in vacuum. The annealing duration was varied between 5 and 20 minutes. The structural and optical properties of the films were ascertained by x-ray diffraction (XRD) and uv-vis-nir spectrophotometry (photon wavelength ranging between 300 and 2500 nm), respectively. The diffractogram indicated that these films were polycrystalline in nature having tetragonal structure with lattice parameters, a ∼ 6.0034 A and c ∼ 10.9165 A. The optical transmittance and reflectance were utilized to compute the absorption coefficient, refractive index and energy gap of the films. Dependence of the optical and structural properties of the films on various annealing durations has been analyzed. The nature of the optical transitions has been direct allowed with band gap energies ranging between 1.713 and 1.757 eV and refractive indices between 1.596 and 3.351 depending on photon energy as well as annealing duration. (authors)

  12. Study of the effect of the deposition parameters on the structural, electric and optical characteristics of polymorphous silicon films prepared by low frequency PECVD

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, M., E-mail: mmoreno@inaoep.mx [Instituto Nacional de Astrofisica, Optica y Electronica, INAOE, Puebla (Mexico); Torres, A. [Instituto Nacional de Astrofisica, Optica y Electronica, INAOE, Puebla (Mexico); Ambrosio, R. [Universidad Autonoma de Ciudad Juarez, Electrical Deparment, Chihuahua (Mexico); Zuniga, C.; Torres-Rios, A.; Monfil, K.; Rosales, P.; Itzmoyotl, A. [Instituto Nacional de Astrofisica, Optica y Electronica, INAOE, Puebla (Mexico)

    2011-10-25

    In this work we present our results on the deposition and characterization of polymorphous silicon (pm-Si:H) films prepared by low frequency plasma enhanced chemical vapor deposition (LF-PECVD). We have studied the effect of the plasma deposition parameters (as the chamber pressure and gas flow rates of SiH{sub 4} and H{sub 2}) on the structural, electric, and optical characteristics of the films. The temperature dependence of conductivity ({sigma}(T)), activation energy (E{sub a}), optical band gap (E{sub g}) and deposition rate (V{sub d}) were extracted for pm-Si:H films deposited at different pressure values and different gas flow rates. We observed that the chamber pressure is an important parameter that has a significant effect on the electric characteristics, and as well on the morphology of the pm-Si:H films (deduced from atomic force microscopy). It was found an optimal pressure range, in order to produce pm-Si:H films with high E{sub a} and room temperature conductivity, {sigma}{sub RT}, which are key parameters for thermal detection applications.

  13. Study of the effect of the deposition parameters on the structural, electric and optical characteristics of polymorphous silicon films prepared by low frequency PECVD

    International Nuclear Information System (INIS)

    Moreno, M.; Torres, A.; Ambrosio, R.; Zuniga, C.; Torres-Rios, A.; Monfil, K.; Rosales, P.; Itzmoyotl, A.

    2011-01-01

    In this work we present our results on the deposition and characterization of polymorphous silicon (pm-Si:H) films prepared by low frequency plasma enhanced chemical vapor deposition (LF-PECVD). We have studied the effect of the plasma deposition parameters (as the chamber pressure and gas flow rates of SiH 4 and H 2 ) on the structural, electric, and optical characteristics of the films. The temperature dependence of conductivity (σ(T)), activation energy (E a ), optical band gap (E g ) and deposition rate (V d ) were extracted for pm-Si:H films deposited at different pressure values and different gas flow rates. We observed that the chamber pressure is an important parameter that has a significant effect on the electric characteristics, and as well on the morphology of the pm-Si:H films (deduced from atomic force microscopy). It was found an optimal pressure range, in order to produce pm-Si:H films with high E a and room temperature conductivity, σ RT , which are key parameters for thermal detection applications.

  14. Optical packet switched design with relaxed maximum hardware parameters and high service-class granularity for flexible switch node dimensioning

    DEFF Research Database (Denmark)

    Nord, Martin

    2004-01-01

    This work proposes a quality of service differentiation algorithm, improving the service class granularity and isolation of our recently presented waveband plane based design. The design aims at overcoming potential hardware limitations and increasing the switch node dimensioning flexibility...... in core networks. Exploiting the wavelength dimension for contention resolution, using partially shared wavelength converter pools, avoids optical buffers and reduces wavelength converter count. These benefits are illustrated by numerical simulations, and are highlighted in a dimensioning study with three...

  15. Influence of sputtering deposition parameters on electrical and optical properties of aluminium-doped zinc oxide thin films for photovoltaic applications

    Directory of Open Access Journals (Sweden)

    Krawczak Ewelina

    2017-01-01

    Full Text Available Transparent Conductive Oxides (TCOs characterized by high visible transmittance and low electrical resistivity play an important role in photovoltaic technology. Aluminum doped zinc oxide (AZO is one of the TCOs that can find its application in thin film solar cells (CIGS or CdTe PV technology as well as in other microelectronic applications. In this paper some optical and electrical properties of ZnO:Al thin films deposited by RF magnetron sputtering method have been investigated. AZO layers have been deposited on the soda lime glass substrates with use of variable technological parameters such as pressure in the deposition chamber, power applied and temperature during the process. The composition of AZO films has been investigated by EDS method. Thickness and refraction index of the deposited layers in dependence on certain technological parameters of sputtering process have been determined by spectroscopic ellipsometry. The measurements of transmittance and sheet resistance were also performed.

  16. Influence of sputtering deposition parameters on electrical and optical properties of aluminium-doped zinc oxide thin films for photovoltaic applications

    Science.gov (United States)

    Krawczak, Ewelina; Agata, Zdyb; Gulkowski, Slawomir; Fave, Alain; Fourmond, Erwann

    2017-11-01

    Transparent Conductive Oxides (TCOs) characterized by high visible transmittance and low electrical resistivity play an important role in photovoltaic technology. Aluminum doped zinc oxide (AZO) is one of the TCOs that can find its application in thin film solar cells (CIGS or CdTe PV technology) as well as in other microelectronic applications. In this paper some optical and electrical properties of ZnO:Al thin films deposited by RF magnetron sputtering method have been investigated. AZO layers have been deposited on the soda lime glass substrates with use of variable technological parameters such as pressure in the deposition chamber, power applied and temperature during the process. The composition of AZO films has been investigated by EDS method. Thickness and refraction index of the deposited layers in dependence on certain technological parameters of sputtering process have been determined by spectroscopic ellipsometry. The measurements of transmittance and sheet resistance were also performed.

  17. [INVITED] Porphyrin-nanoassembled fiber-optic gas sensor fabrication: Optimization of parameters for sensitive ammonia gas detection

    Science.gov (United States)

    Korposh, Sergiy; Kodaira, Suguru; Selyanchyn, Roman; Ledezma, Francisco H.; James, Stephen W.; Lee, Seung-Woo

    2018-05-01

    Highly sensitive fiber-optic ammonia gas sensors were fabricated via layer-by-layer deposition of poly(diallyldimethylammonium chloride) (PDDA) and tetrakis(4-sulfophenyl)porphine (TSPP) onto the surface of the core of a hard-clad multimode fiber that was stripped of its polymer cladding. The effects of film thickness, length of sensing area, and depth of evanescent wave penetration were investigated to clearly understand the sensor performance. The sensitivity of the fiber-optic sensor to ammonia was linear in the concentration range of 0.5-50 ppm and the response and recovery times were less than 3 min, with a limit of detection of 0.5 ppm, when a ten-cycle PDDA/TSPP film was assembled on the surface of the core along a 1 cm-long stripped section of the fiber. The sensor's response towards ammonia was also checked under different relative humidity conditions and a simple statistical data treatment approach, principal component analysis, demonstrated the feasibility of ammonia sensing in environmental relative humidity ranging from dry 7% to highly saturated 80%. Penetration depths of the evanescent wave for the optimal sensor configuration were estimated to be 30 and 33 nm at wavelengths of 420 and 706 nm, which are in a good agreement with the thickness of the 10-cycle deposited film (ca. 30 nm).

  18. Complex of structural roentgenometric and optical parameters of chest X-ray picture for automated fluorograms processing

    International Nuclear Information System (INIS)

    Rodzaevskij, S.A.

    1986-01-01

    The formalized description necessary for the development of algorithms for determination of main object boundaries by the roentgenologic picture during computerized photoroentgenograms processing is drawn up on the basis of the complex of structural roentgenometric parameters of the chest X-ray picture

  19. Influence of gamma ray irradiation and annealing temperature on the optical constants and spectral dispersion parameters of metal-free and zinc tetraphenylporphyrin thin films: A comparative study.

    Science.gov (United States)

    Zeyada, H M; Makhlouf, M M; El-Nahass, M M

    2015-09-05

    In this work, we report on the effect of γ-ray irradiation and annealing temperature on the optical properties of metal-free tetraphenylporphyrin, H2TPP, and zinc tetraphenylporphyrin, ZnTPP, thin films. Thin films of H2TPP and ZnTPP were successfully prepared by the thermal evaporation technique. The optical properties of H2TPP and ZnTPP films were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 2500 nm. The absorption spectra of H2TPP showed four absorption bands, namely the Q, B, N and M bands. The effect of inserting Zn atom into the cavity of porphyrin macrocycle in ZnTPP molecule distorted the Q and B bands, reduced the width of absorption region and influenced the optical constants and dispersion parameters. In all conditions, the type of electron transition is indirect allowed transition. Anomalous dispersion is observed in the absorption region but normal dispersion occurs in the transparent region of spectra. We adopted multi-oscillator model and the single oscillator model to interpret the anomalous and normal dispersion, respectively. We have found that the annealing temperature has mostly the opposite effect of γ-ray irradiation on absorption and dispersion characteristics of these films. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Study of an Impact-Parameter Optical Discriminator to be used for Beauty Search in Fixed-Target Mode~ at~the~LHC

    CERN Multimedia

    2002-01-01

    % RD30 \\\\ \\\\ We propose a research and development of an $^{\\prime}$Optical Trigger$^{\\prime}$ to be used for B-meson selection in a LHC fixed-target experiment. The optical trigger relies on the detection of Cerenkov light produced and trapped in a thin spherical crystal viewed by a fast photodetector. The device is, in principle, sensitive to charged particles with large impact parameter arising from secondary vertices belonging to the B-meson chain, but it is blind to minimum bias events originating in a small target. A full prototype using LiF fluoride crystal in 1992 and the experimental results are in agreement with expectations. Backgrounds due to delta-rays and nuclear interactions are measured to be about 2\\%. A second generation prototype with Sapphire crystal and liquid cladding is developed to improve the sensitivity of the device at very low impact parameters (100~$\\mu$m). A third generation prototype with fiber read-out is also under preparation. To improve further the sensitivity a novel read-o...

  1. Link between optical spectra, crystal-field parameters, and local environments of Eu3+ ions in Eu2O3-doped sodium disilicate glass

    International Nuclear Information System (INIS)

    Qin, T.; Mountjoy, G.; Afify, N. D.; Reid, M. F.; Yeung, Y. Y.; Speghini, A.; Bettinelli, M.

    2011-01-01

    Rare-earth-doped glasses are key materials for optical technology due to the luminescent properties of 4f n ions. The crystal-field model describes the effect of local environment on transitions between 4f electrons. We present a detailed modeling study of the optical spectra of sodium disilicate glass, 33Na 2 O·67SiO 2 , doped with 0.2% and 1.0 mol%Eu 2 O 3 . This study uses very large molecular dynamics models with up to 100 Eu 3+ ions, the superposition model for covalent and overlap effects on crystal-field parameters, and realistic values for homogeneous linewidth broadening. The simulated spectra are in reasonable agreement with experiment. The trends in 7 F J energy levels across different Eu 3+ ion sites have been examined and a very detailed analysis is presented that looks at how features of the spectra are related to features of the local environment of Eu 3+ ions. Increasing the crystal-field strength S total causes the 7 F 0 energy level to decrease and causes the splitting of 7 F J manifolds to increase, and this is due to increasing mixing of 4f wave functions. To a reasonable approximation the crystal-field strength components S k depend on angular positions of ligands independently of distances to ligands. The former are seen to be more significant in determining S k , which are closely related to the rotationally invariant bond-orientational order parameters Q k . The values of S 2 are approximately linear in Q 2 , and the values of Q 2 are higher for fivefold than sixfold coordinated rare-earth ions. These results can be of importance for efforts to enhance the local environment of rare-earth ions in oxide glasses for optical applications.

  2. Assessment of Corneal and Tear Film Parameters in Rheumatoid Arthritis Patients Using Anterior Segment Spectral Domain Optical Coherence Tomography.

    Science.gov (United States)

    El-Fayoumi, Dina; Youssef, Maha Mohamed; Khafagy, Mohamed Mahmoud; Badr El Dine, Nashwa; Gaber, Wafaa

    2018-01-01

    To study the corneal changes in rheumatoid arthritis (RA) patients in vivo, using spectral domain anterior segment optical coherence tomography (AS-OCT). A case-control study was done on 43 RA patients and 40 controls. The disease activity score (DAS28-ESR) was calculated and all participants had lower tear meniscus, corneal thickness, and epithelial thickness evaluation using AS-OCT. The lower tear meniscus height (LTMH) and the lower tear meniscus area (LTMA) were significantly lower in the RA patients than in controls (p < 0.001). RA patients also had a significantly thinner central corneal thickness (p = 0.02) and their epithelium was found to be thinner in the superotemporal peripheral sector. The LTMH and LTMA are significantly reduced in RA patients, despite the absence of clinical diagnosis of dry eye. RA patients have thinner corneal thickness and epithelial thickness than controls, which did not correlate with either disease duration or activity.

  3. Strain tuneable whispering gallery mode resonators in the estimation of the elasto-optic parameters of soft materials

    Science.gov (United States)

    Pissadakis, Stavros; Milenko, Karolina; Aluculesei, Alina; Fytas, George

    2016-04-01

    In this manuscript we present the fabrication and characterization of a novel, polymer whispering gallery modes (WGMs) spherical micro-resonator, formed around the waist of an optical fiber taper. Fiber taper with well attached spheroid works as a cord, fixed on two ends enabling strain application to the resonator body. Controllable elastic elongation of the encapsulated fiber taper causes a change in the shape of the spheroid, which modifies the diameter and directional refractive index of the cavity. These changes influence the wavelength position of the WGMs resonances with a linear blue shift up to 0.6 nm, with corresponding strains up to 700Μɛ. The strain induced WGMs shift with respect to resonator diameter and annealing process is presented and analyzed.

  4. Computational code in atomic and nuclear quantum optics: Advanced computing multiphoton resonance parameters for atoms in a strong laser field

    Science.gov (United States)

    Glushkov, A. V.; Gurskaya, M. Yu; Ignatenko, A. V.; Smirnov, A. V.; Serga, I. N.; Svinarenko, A. A.; Ternovsky, E. V.

    2017-10-01

    The consistent relativistic energy approach to the finite Fermi-systems (atoms and nuclei) in a strong realistic laser field is presented and applied to computing the multiphoton resonances parameters in some atoms and nuclei. The approach is based on the Gell-Mann and Low S-matrix formalism, multiphoton resonance lines moments technique and advanced Ivanov-Ivanova algorithm of calculating the Green’s function of the Dirac equation. The data for multiphoton resonance width and shift for the Cs atom and the 57Fe nucleus in dependence upon the laser intensity are listed.

  5. Validation of two-dimensional and three-dimensional measurements of subpleural alveolar size parameters by optical coherence tomography

    Science.gov (United States)

    Unglert, Carolin I.; Warger, William C.; Hostens, Jeroen; Namati, Eman; Birngruber, Reginald; Bouma, Brett E.; Tearney, Guillermo J.

    2012-12-01

    Optical coherence tomography (OCT) has been increasingly used for imaging pulmonary alveoli. Only a few studies, however, have quantified individual alveolar areas, and the validity of alveolar volumes represented within OCT images has not been shown. To validate quantitative measurements of alveoli from OCT images, we compared the cross-sectional area, perimeter, volume, and surface area of matched subpleural alveoli from microcomputed tomography (micro-CT) and OCT images of fixed air-filled swine samples. The relative change in size between different alveoli was extremely well correlated (r>0.9, Pvolume), and 25% (surface area) on average. We hypothesized that the differences resulted from refraction at the tissue-air interfaces and developed a ray-tracing model that approximates the reconstructed alveolar size within OCT images. Using this model and OCT measurements of the refractive index for lung tissue (1.41 for fresh, 1.53 for fixed), we derived equations to obtain absolute size measurements of superellipse and circular alveoli with the use of predictive correction factors. These methods and results should enable the quantification of alveolar sizes from OCT images in vivo.

  6. Factors affecting measurement of optic parameters by time-resolved near-infrared spectroscopy in breast cancer

    Science.gov (United States)

    Yoshizawa, Nobuko; Ueda, Yukio; Mimura, Tetsuya; Ohmae, Etsuko; Yoshimoto, Kenji; Wada, Hiroko; Ogura, Hiroyuki; Sakahara, Harumi

    2018-02-01

    The purpose of this study was to evaluate the effects of the thickness and depth of tumors on hemoglobin measurements in breast cancer by optical spectroscopy and to demonstrate tissue oxygen saturation (SO2) and reduced scattering coefficient (μs‧) in breast tissue and breast cancer in relation to the skin-to-chest wall distance. We examined 53 tumors from 44 patients. Total hemoglobin concentration (tHb), SO2, and μs‧ were measured by time-resolved spectroscopy (TRS). The skin-to-chest wall distance and the size and depth of tumors were measured by ultrasonography. There was a positive correlation between tHb and tumor thickness, and a negative correlation between tHb and tumor depth. SO2 in breast tissue decreased when the skin-to-chest wall distance decreased, and SO2 in tumors tended to be lower than in breast tissue. In breast tissue, there was a negative correlation between μs‧ and the skin-to-chest wall distance, and μs‧ in tumors was higher than in breast tissue. Measurement of tHb in breast cancer by TRS was influenced by tumor thickness and depth. Although SO2 seemed lower and μs‧ was higher in breast cancer than in breast tissue, the skin-to-chest wall distance may have affected the measurements.

  7. The Contralateral Connections of Optical Pathway in Chick Brain%鸡脑光信息通路的对侧联系

    Institute of Scientific and Technical Information of China (English)

    刘春凌; 胡满; 王鹏; 张利卫; 杨昊; 刘振斌

    2012-01-01

      Purpose:In order to further understand the nerve regulation mechanism in affect of light on chick pro-duction performance so as to provide some theoretical basis for the application on the using of light to improve the chick production performance and on the veterinary nerve surgery, the contralateral connections of optical pathway in chick brain were observed using HRP tracing method. Methods: Small amount of 3% WGA-HRP was injected into Rt in chicken brain using the stereotaxic instrument. After survival period of 30 hours, the chicks were per-fused to fix the animals. The brains were removed and were sectioned by the cryostat. The HRP labeled nervous cells projecting to contralateral side in the optical pathway were tested using TMB method. Results: After injecting WGA-HRP into nucleus rotundus, besides the numerous labled nervous cells in the ipsilateral SGC and SP/IPS of the chicken tectofugal optical pathway, some HRP labeled nervous cells and fibers were also observed in the con-tralateral SGC, SP/IPS and nucleus rotundus. Their number is fewer than those of the ipsilateral side, having smaller distributing area. The locations of the labeled nervous cells and fibers are different with the regions of the contralateral nucleus rotundus. Their labeled extent showed a spindlye shape from the anterior to the posterior part of the nucleus rotundus. Discussion: The results indicated that the ipsilateral projection is the main projection in the tectofugal optical pathway. There are also some contralateral projections in it. The contralateral projections may play a role by assistant and inhibition process. The projection could make the specific units combined and man-aged the messages came from binoculus, being helpful for the cerebrum to gain more exact and overall messages.%  目的:为了进一步阐明光照对鸡生产性能的神经调节机制,为养鸡生产科学利用光照和兽医神经外科学提供一定的理论依据,用 HRP 追踪技术

  8. Random photonic crystal optical memory

    International Nuclear Information System (INIS)

    Wirth Lima Jr, A; Sombra, A S B

    2012-01-01

    Currently, optical cross-connects working on wavelength division multiplexing systems are based on optical fiber delay lines buffering. We designed and analyzed a novel photonic crystal optical memory, which replaces the fiber delay lines of the current optical cross-connect buffer. Optical buffering systems based on random photonic crystal optical memory have similar behavior to the electronic buffering systems based on electronic RAM memory. In this paper, we show that OXCs working with optical buffering based on random photonic crystal optical memories provides better performance than the current optical cross-connects. (paper)

  9. Effect of angle of deposition on micro-roughness parameters and optical properties of HfO{sub 2} thin films deposited by reactive electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Tokas, R.B., E-mail: tokasstar@gmail.com; Jena, S.; Thakur, S.; Sahoo, N.K.

    2016-06-30

    Oblique angle deposited oxide thin films, in which refractive index profiles can be tailored across depth by tuning their microstructure using varying angle of deposition, have opened up new dimensions in fabrication of optical interference devices. Since surface morphology plays an important role for the qualification of these thin film devices for optical or other applications, it is important to investigate morphological properties of obliquely deposited thin films. In the present work, a set of HfO{sub 2} thin films have been deposited at several oblique angles. Morphological parameters of such thin films viz., correlation length, intrinsic roughness, fractal spectral strength, etc., have been determined through suitable modelling of extended power spectral density measured by atomic force microscopy. It has been found that intrinsic roughness and fractal spectral strength show an interesting behaviour with deposition angle and the same has been discussed in the light of atomic shadowing and re-emission and diffusion of ad-atoms. Further refractive index and thickness of such thin films have been estimated from optical transmission spectra through suitable modelling. Refractive index of such thin film varies from 1.93 to 1.37 as the deposition angle varies from normal to glancing angle (80°). Further, refractive index and grain size depict an opposite trend with deposition angle. This variation has been explained in terms of varying film porosity and column slanting with angle of deposition. - Highlights: • HfO{sub 2} thin films deposited at several oblique angles • Film deposited at 80° exhibits the highest grain size and intrinsic roughness (σ). • Fractal strength and σ depict an interesting trend with angle of deposition. • Refractive index and grain size depict an opposite trend with angle of deposition.

  10. Spatial and optical parameters of contrails in the vortex and dispersion regime determined by means of a ground-based scanning lidar

    Energy Technology Data Exchange (ETDEWEB)

    Freudenthaler, V; Homburg, F; Jaeger, H [Fraunhofer-Inst. fuer Atmosphaerische Umweltforschung (IFU), Garmisch-Partenkirchen (Germany)

    1998-12-31

    The spatial growth of individual condensation trails (contrails) of commercial aircrafts in the time range from 15 s to 60 min behind the aircraft is investigated by means of a ground-based scanning backscatter lidar. The growth in width is mainly governed by wind shear and varies between 18 m/min and 140 m/min. The growth of the cross-section varies between 3500 m{sup 2}/min and 25000 m{sup 2}/min. These values are in agreement with results of model calculations and former field measurements. The vertical growth is often limited by boundaries of the humid layer at flight level, but values up to 18 m/min were observed. Optical parameters like depolarization, optical depth and lidar ratio, i.e. the extinction-to-backscatter ratio, have been retrieved from the measurements at a wavelength of 532 nm. The linear depolarization rises from values as low as 0.06 for a young contrail (10 s old) to values around 0.5, typical for aged contrails. The latter indicates the transition from non-crystalline to crystalline particles in persistent contrails within a few minutes. The scatter of depolarization values measured in individual contrails is narrow, independent of the contrails age, and suggests a rather uniform growth of the particles inside a contrail. (author) 18 refs.

  11. Temperature behaviour of optical parameters in (Ag3AsS3)0.3(As2S3)0.7 thin films

    Science.gov (United States)

    Kutsyk, Mykhailo M.; Ráti, Yosyp Y.; Izai, Vitalii Y.; Makauz, Ivan I.; Studenyak, Ihor P.; Kökényesi, Sandor; Komada, Paweł; Zhailaubayev, Yerkin; Smailov, Nurzhigit

    2015-12-01

    (Ag3AsS3)0.3(As2S3)0.7 thin films were deposited onto a quartz substrate by rapid thermal evaporation. The optical transmission spectra of thin films were measured in the temperature range 77-300 K. It is shown that the absorption edge spectra are described by the Urbach rule. The temperature behaviour of absorption spectra was studied, the temperature dependences of energy position of absorption edge and Urbach energy were investigated. The influence of transition from three-dimensional glass to the two-dimensional thin film as well as influence of Ag3AsS3 introduction into As2S3 on the optical parameters of (Ag3AsS3)0.3(As2S3)0.7 were analysed. The spectral and temperature behaviour or refractive index for (Ag3AsS3)0.3(As2S3)0.7 thin film were studied.

  12. Spatial and optical parameters of contrails in the vortex and dispersion regime determined by means of a ground-based scanning lidar

    Energy Technology Data Exchange (ETDEWEB)

    Freudenthaler, V.; Homburg, F.; Jaeger, H. [Fraunhofer-Inst. fuer Atmosphaerische Umweltforschung (IFU), Garmisch-Partenkirchen (Germany)

    1997-12-31

    The spatial growth of individual condensation trails (contrails) of commercial aircrafts in the time range from 15 s to 60 min behind the aircraft is investigated by means of a ground-based scanning backscatter lidar. The growth in width is mainly governed by wind shear and varies between 18 m/min and 140 m/min. The growth of the cross-section varies between 3500 m{sup 2}/min and 25000 m{sup 2}/min. These values are in agreement with results of model calculations and former field measurements. The vertical growth is often limited by boundaries of the humid layer at flight level, but values up to 18 m/min were observed. Optical parameters like depolarization, optical depth and lidar ratio, i.e. the extinction-to-backscatter ratio, have been retrieved from the measurements at a wavelength of 532 nm. The linear depolarization rises from values as low as 0.06 for a young contrail (10 s old) to values around 0.5, typical for aged contrails. The latter indicates the transition from non-crystalline to crystalline particles in persistent contrails within a few minutes. The scatter of depolarization values measured in individual contrails is narrow, independent of the contrails age, and suggests a rather uniform growth of the particles inside a contrail. (author) 18 refs.

  13. Connecting Grammaticalisation

    DEFF Research Database (Denmark)

    Nørgård-Sørensen, Jens; Heltoft, Lars; Schøsler, Lene

    morphological, topological and constructional paradigms often connect to form complex paradigms. The book introduces the concept of connecting grammaticalisation to describe the formation, restructuring and dismantling of such complex paradigms. Drawing primarily on data from Germanic, Romance and Slavic...

  14. Estimation of the effect of radionuclide contamination on Vicia sativa L. induction of chlorophyll fluorescence parameters using "Floratest" optical biosensor

    Science.gov (United States)

    Ruban, Yu.; Illienko, V.; Nesterova, N.; Pareniuk, O.; Shavanova, K.

    2017-12-01

    The presented research was aimed to determine the parameters of chlorophyll fluorescence (IChH) curve induction for Vicia sativa L. that were grown on radionuclide contaminated soils by using "Floratest" fluorometer. Plants were inoculated with 5 species of bacteria that might potentially block radionuclide uptake (Agrobacterium radiobacter IMBB-7246, Azotobacter chroococcum UKMB-6082, A. chroococcum UKMB-6003, Bacillus megaterium UKMB-5724, Rhizobium leguminosarum bv. viceae) and grown in sod-podzolic, chernozem and peat-bog soils, contaminated with 137Cs (4000±340 Bq/kg). As a result of research, it was determined that the most stressful factors for vetch plants are combination of soil radionuclide and presence of Bacillus megaterium UKM B-5724, as the number of inactive chlorophyll increased. In addition, the vetch plants significantly increased fixed level of fluorescence (Fst) under the influence of radioactive contamination in presence of Bacillus megaterium UKM B-5724, indicating inhibition of photosynthetic reactions. Other bacteria showed radioprotective properties in almost all types of soil.

  15. Optimization of digestion parameters for analysing the total sulphur of mine tailings by inductively coupled plasma optical emission spectrometry.

    Science.gov (United States)

    Alam, Raquibul; Shang, Julie Q; Cheng, Xiangrong

    2012-05-01

    The oxidation of sulphidic mine tailings and consequent acid generation poses challenges for the environment. Accurate and precise analysis of sulphur content is necessary for impact assessment and management of mine tailings. Here, the authors aim at developing a rapid and easy digestion procedure, which may analyse and measure the total amount of sulphur in mine tailings by using inductively coupled plasma. For evaluating effects of several variables, the researchers used a univariate (analysis of variance (ANOVA)) strategy and considered factors such as composition of the acid mixture, heating time, and refluxing device to optimize the performance. To do the experiment, the researchers have used two certified reference materials (KZK-1 and RTS-2) and samples of tailings from Musselwhite mine. ANOVA result shows that heating time is the most influencing factor on acid digestion of the reference materials whereas in case of a digestion of tailings sample, hydrochloric acid proved to be the most significant parameter. Satisfactory results between the measured and referenced values are found for all experiments. It is found that the aqua regia (1 ml HNO(3) + 3 ml HCl) digestion of 0.1 g of samples after only 40 min of heating at 95°C produced fast, safe, and accurate analytical results with a recovery of 97% for the selected reference materials.

  16. The potential of computer vision, optical backscattering parameters and artificial neural network modelling in monitoring the shrinkage of sweet potato (Ipomoea batatas L.) during drying.

    Science.gov (United States)

    Onwude, Daniel I; Hashim, Norhashila; Abdan, Khalina; Janius, Rimfiel; Chen, Guangnan

    2018-03-01

    Drying is a method used to preserve agricultural crops. During the drying of products with high moisture content, structural changes in shape, volume, area, density and porosity occur. These changes could affect the final quality of dried product and also the effective design of drying equipment. Therefore, this study investigated a novel approach in monitoring and predicting the shrinkage of sweet potato during drying. Drying experiments were conducted at temperatures of 50-70 °C and samples thicknesses of 2-6 mm. The volume and surface area obtained from camera vision, and the perimeter and illuminated area from backscattered optical images were analysed and used to evaluate the shrinkage of sweet potato during drying. The relationship between dimensionless moisture content and shrinkage of sweet potato in terms of volume, surface area, perimeter and illuminated area was found to be linearly correlated. The results also demonstrated that the shrinkage of sweet potato based on computer vision and backscattered optical parameters is affected by the product thickness, drying temperature and drying time. A multilayer perceptron (MLP) artificial neural network with input layer containing three cells, two hidden layers (18 neurons), and five cells for output layer, was used to develop a model that can monitor, control and predict the shrinkage parameters and moisture content of sweet potato slices under different drying conditions. The developed ANN model satisfactorily predicted the shrinkage and dimensionless moisture content of sweet potato with correlation coefficient greater than 0.95. Combined computer vision, laser light backscattering imaging and artificial neural network can be used as a non-destructive, rapid and easily adaptable technique for in-line monitoring, predicting and controlling the shrinkage and moisture changes of food and agricultural crops during drying. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  17. The role of low light intensity: A step towards understanding the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells

    Science.gov (United States)

    Lojpur, Vesna; Mitrić, Miodrag; Validžić, Ivana Lj

    2018-05-01

    We report here an optic/lens system that we used so far, for cooling the surface of solar cells, the reduction of light intensity and the change of light distribution that reaches the surface of the solar cell. The objective was to improve photovoltaic characteristics under very low light illumination, as well as to understand the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells. It was found that for all so far designed thin-film solar cells made and based on the synthesized Sb2S3, optics/lens system causes an increase in open circuit voltage (VOC) and short circuit current (ISC) and thus the efficiencies of made solar devices. Values of energy gaps for the thin-films made devices were in the range from 1.4 to 2 eV. Improvements of the photovoltaic response of the designed devices are found to be better at the lower light intensity (5% sun), than at higher intensities of light. For the same intensity of light used optic/lens improves the efficiency of the devices, by changing the light distribution. Other processes that are related to the optics/lens system, leading to an increase in ISC and VOC and consequently to an increase in efficiencies of the designed devices, are investigated.

  18. Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography.

    Science.gov (United States)

    Chansangpetch, Sunee; Nguyen, Anwell; Mora, Marta; Badr, Mai; He, Mingguang; Porco, Travis C; Lin, Shan C

    2018-03-01

    To assess the interdevice agreement between swept-source Fourier-domain and time-domain anterior segment optical coherence tomography (AS-OCT). Fifty-three eyes from 41 subjects underwent CASIA2 and Visante OCT imaging. One hundred eighty-degree axis images were measured with the built-in two-dimensional analysis software for the swept-source Fourier-domain AS-OCT (CASIA2) and a customized program for the time-domain AS-OCT (Visante OCT). In both devices, we examined the angle opening distance (AOD), trabecular iris space area (TISA), angle recess area (ARA), anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). Bland-Altman plots and intraclass correlation (ICC) were performed. Orthogonal linear regression assessed any proportional bias. ICC showed strong correlation for LV (0.925) and ACD (0.992) and moderate agreement for ACW (0.801). ICC suggested good agreement for all angle parameters (0.771-0.878) except temporal AOD500 (0.743) and ARA750 (nasal 0.481; temporal 0.481). There was a proportional bias in nasal ARA750 (slope 2.44, 95% confidence interval [CI]: 1.95-3.18), temporal ARA750 (slope 2.57, 95% CI: 2.04-3.40), and nasal TISA500 (slope 1.30, 95% CI: 1.12-1.54). Bland-Altman plots demonstrated in all measured parameters a minimal mean difference between the two devices (-0.089 to 0.063); however, evidence of constant bias was found in nasal AOD250, nasal AOD500, nasal AOD750, nasal ARA750, temporal AOD500, temporal AOD750, temporal ARA750, and ACD. Among the parameters with constant biases, CASIA2 tends to give the larger numbers. Both devices had generally good agreement. However, there were proportional and constant biases in most angle parameters. Thus, it is not recommended that values be used interchangeably.

  19. RPC Calculations for K-forbidden Transitions in {sup 183}W, Evidence for Large Inertial Parameter Connected with High-lying Rotational Bands

    Energy Technology Data Exchange (ETDEWEB)

    Malmskog, S G [AB Atomenergi, Nykoeping (Sweden); Wahlborn, S [Div. of Theore tical Physics, Royal Inst. of Technology Stockholm (Sweden)

    1967-09-15

    Recent measurements have shown that the transitions deexciting the 453 keV 7/2{sup -} level in {sup 183}W to the K = 1/2{sup -} and 3/2{sup -} bands are strongly retarded. The data for B(M1) and B(E2) are analyzed in terms of the RPC model (rotation + particle motion + coupling). With the {delta}K = 1 (Coriolis) coupling, the K-forbidden M1-transitions proceed via admixtures of high-lying 5/2{sup -} bands. A reasonable and unambiguous fit to the data is obtained by varying the strength of the coupling. Allowing for various uncertainties and corrections, one finds that the inertial parameter (the inverse of the coupling constant, i. e. 2J(2{pi}){sup 2}/({Dirac_h}){sup 2} may have values between roughly 1 and 3 times the rigid rotator value of 2J(2{pi}){sup 2}/({Dirac_h}){sup 2}, thus being unexpectedly large. Calculations with the {delta}K=2 coupling were also performed and turn out not to give better agreement with experiment.

  20. A method to obtain the thermal parameters and the photothermal transduction efficiency in an optical hyperthermia device based on laser irradiation of gold nanoparticles.

    Science.gov (United States)

    Sánchez López de Pablo, Cristina; Olmedo, José Javier Serrano; Rosales, Alejandra Mina; Ramírez Hernández, Norma; Del Pozo Guerrero, Francisco

    2014-01-01

    Optical hyperthermia systems based on the laser irradiation of gold nanorods seem to be a promising tool in the development of therapies against cancer. After a proof of concept in which the authors demonstrated the efficiency of this kind of systems, a modeling process based on an equivalent thermal-electric circuit has been carried out to determine the thermal parameters of the system and an energy balance obtained from the time-dependent heating and cooling temperature curves of the irradiated samples in order to obtain the photothermal transduction efficiency. By knowing this parameter, it is possible to increase the effectiveness of the treatments, thanks to the possibility of predicting the response of the device depending on the working configuration. As an example, the thermal behavior of two different kinds of nanoparticles is compared. The results show that, under identical conditions, the use of PEGylated gold nanorods allows for a more efficient heating compared with bare nanorods, and therefore, it results in a more effective therapy.

  1. Early changes in macular optical coherence tomography parameters after Ranibizumab intravitreal injection in patients with exsudative age-related macular degeneration.

    Science.gov (United States)

    de Almeida, Nicole Antunes; de Souza, Osias Francisco

    2018-01-01

    Evaluation of the impact of different macular optical coherence parameters on visual acuity as early as 1 day after injection of ranibizumab in patients with subfoveal exsudative age-related macular degeneration. This was an interventional, non randomized, open label prospective study, where we evaluated 20 eyes of 20 patients affected by exudative age-related macular degeneration. These patients were treated with injections of ranibizumab between February 2013 and January 2015. The primary endpoint of this study was to evaluate the early changes in optical coherence tomography parameters (retinal thickness, central and total retinal volume) and impact on best-corrected visual acuity (BCVA) obtained by logarithm of minimum resolution using ETDRS protocol in patients treated with a single dose intravitreal injection of ranibizumab (0.5 mg/0.05 mL) during the first month of follow. The patients were evaluated on the first day, them at 7 and 30 days after the treatment. The National Eye Institute Visual Functioning Questionnaire was applied during the study period to assess early perception of ranibizumab injection effectiveness. The adverse events were monitored throughout the study. Central retinal thickness values at 1 (464.0 ± 97.8 µm), 7 (379.9 ± 107.8 µm) and 30 days (365.5 ± 95.1 µm) after ranibizumab injection showed a statically significant reduction when compared with baseline results ( P  = 0.01, P  = 0.001, P  = 0.001, respectively). Similar alterations were observed in central and total retinal volume, which were detected early on the first day of evaluation, after the measurement at baseline (central: 0.36 ± 0.07 vs. 0.40 ± 0.10 mm 3 , P  = 0.01; total: 9.62 ± 1.10 vs. 9.99 ± 2.56 mm 3 , P  = 0.002) and remained steady at 7 ( P  = 0.001, P  = 0.002, respectively) and 30 days ( P  = 0.001, P  = 0.004, respectively) with slight variations without losing their gains in these parameters. The best

  2. Optic Nerve Disorders

    Science.gov (United States)

    The optic nerve is a bundle of more than 1 million nerve fibers that carry visual messages. You have one connecting ... retina) to your brain. Damage to an optic nerve can cause vision loss. The type of vision ...

  3. Measurement of optical glasses

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1978-11-01

    The possibilities of measurement of the optical glasses parameters needed in building optical devices especially in lasers devices are presented. In the first chapter the general features of the main optical glasses as well as the modalities of obtaining them are given. Chapter two defines the optical glass parameters, and the third chapter describes the measuring methods of the optical glass parameters. Finally, the conclusions which point out the utilization of this paper are presented. (author)

  4. Making Connections

    Science.gov (United States)

    Pien, Cheng Lu; Dongsheng, Zhao

    2011-01-01

    Effective teaching includes enabling learners to make connections within mathematics. It is easy to accord with this statement, but how often is it a reality in the mathematics classroom? This article describes an approach in "connecting equivalent" fractions and whole number operations. The authors illustrate how a teacher can combine a common…

  5. Optical characteristics and parameters of the plasma of a barrier discharge excited in a mixture of mercury dibromide vapor with nitrogen and helium

    Science.gov (United States)

    Malinina, A. A.; Guivan, N. N.; Shimon, L. L.; Shuaibov, A. K.

    2010-09-01

    Results are presented from experimental and theoretical studies of the optical characteristics and parameters of the plasma of an atmospheric-pressure barrier discharge excited in a HgBr2: N2: He mixture, which was used as the working medium of a small-size (with a radiation area of 8 cm2) exciplex gas-discharge radiation source. The mean radiation power of 87 mW was achieved at the radiation wavelength λmax = 502 nm. The electron energy distribution function, the transport characteristics, the specific energy lost in the processes involving electrons, the electron temperature and density, and the rate constants of elastic and inelastic electron scattering by the components of the working mixture were calculated as functions of the reduced field E/ N. The plasma of a discharge excited in a HgBr2: N2: He mixture can be used as the working medium of a small-size blue-green radiation source. Such a source can find application in biotechnology, photonics, and medicine and can also be used to manufacture gas-discharge display panels.

  6. Comparison of anterior segment parameters and axial length measurements performed on a Scheimpflug device with biometry function and a reference optical biometer.

    Science.gov (United States)

    Muzyka-Woźniak, Maria; Oleszko, Adam

    2018-04-26

    To compare measurements of axial length (AL), corneal curvature (K), anterior chamber depth (ACD) and white-to-white (WTW) distance on a new device combining Scheimpflug camera and partial coherence interferometry (Pentacam AXL) with a reference optical biometer (IOL Master 500). To evaluate differences between IOL power calculations based on the two biometers. Ninety-seven eyes of 97 consecutive cataract or refractive lens exchange patients were examined preoperatively on IOL Master 500 and Pentacam AXL units. Comparisons between two devices were performed for AL, K, ACD and WTW. Intraocular lens (IOL) power targeting emmetropia was calculated with SRK/T and Haigis formulas on both devices and compared. There were statistically significant differences between two devices for all measured parameters (P eyes for Haigis formula and in 62% of eyes for SRK/T formula, with a mean difference within ± 0.5 D for 72 and 86% of eyes, respectively. There were statistically significant differences between AL, K and WTW measurements obtained with the compared biometers. Flatter corneal curvature measurements on Pentacam AXL necessitate formulas optimisation for Pentacam AXL.

  7. Values of some topographic parameters of optic nerve head obtained by Heidelberg retina tomograph II in volunteers and different stage primary open-angle glaucoma patients

    Directory of Open Access Journals (Sweden)

    B. Anguelov

    2013-01-01

    Full Text Available Purpose: То assess the values of the top five topographic parameters of optic nerve head (ONH obtained by Heidelberg retina tomograph (HRT II in volunteers and primary open angle glaucoma (POAG patients with different stage of perimetric changes.Methods: 73 eyes (38 volunteers at the age of 56 years ±13, 11 men and 27 women and 170 eyes (90 patients at the age of 66 years ±12, 33 men and 57 women were examined. We performed the comprehensive ophthalmic examination, standard automated perimetry and measurement of the top five topographic parameters of ONH — rim area, rim volume, cup shape measure, height variation contour и mean RNFL thickness. For the purpose of this study we used HRT II.Results: We determine the values of the investigated topographic parameters of the ONH for healthy volunteers (rim area = 1.68±0.22 mm2, rim volume = 0.44±0.07 mm3, cup shape measure = –0.2±0.06, height variation contour = 0.38±0.08 mm and mean RNFL thickness = 0.24±0.03 mm and for the patients in different perimetric glaucoma stages (early stage: rim area = 1.52±0.47 mm2, rim volume = 0.38±0.17 mm3, cup shape measure = –0.14±0.1, height variation contour = 0.36±0.09 mm and mean RNFL thickness = 0.22±0.11 mm; moderate stage: rim area = 1.21±0.46 mm2, rim volume = 0.27±0.17 mm3, cup shape measure = –0.09±0.1, height variation contour = 0.36±0.17 mm and mean RNFL thickness = 0.16±0.12 mm; severe stage: rim area = 0.97±0.01 mm2, rim volume = 0.18±0.17 mm3, cup shape measure = –0.06±0.1, height variation contour = 0.28±0.11 mm and mean RNFL thickness = 0.17±0.11 mm. Hodapp-Parrish-Anderson (H-P-A ’s staging system includes three separate levels (early, moderate and severe of glaucoma according to visual field defects. Each stage is additionally characterized by the values of the top five topographic parameters of the ONH.Conclusion: Early diagnosis, staging and follow-up of POAG are based on both function and

  8. Establishing Age-Adjusted Reference Ranges for Iris-Related Parameters in Open Angle Eyes with Anterior Segment Optical Coherence Tomography.

    Directory of Open Access Journals (Sweden)

    Jeffrey R Peterson

    Full Text Available Define criteria for iris-related parameters in an adult open angle population as measured with swept source Fourier domain anterior segment optical coherence tomography (ASOCT.Ninety-eight eyes of 98 participants with open angles were included and stratified into 5 age groups (18-35, 36-45, 46-55, 56-65, and 66-79 years. ASOCT scans with 3D mode angle analysis were taken with the CASIA SS-1000 (Tomey Corporation, Nagoya, Japan and analyzed using the Anterior Chamber Analysis and Interpretation software. Anterior iris surface length (AISL, length of scleral spur landmark (SSL to pupillary margin (SSL-to-PM, iris contour ratio (ICR = AISL/SSL-to-PM, pupil radius, radius of iris centroid (RICe, and iris volume were measured. Outcome variables were summarized for all eyes and age groups, and mean values among age groups were compared using one-way analysis of variance. Stepwise regression analysis was used to investigate demographic and ocular characteristic factors that affected each iris-related parameter.Mean (±SD values were 2.24 mm (±0.46, 4.06 mm (±0.27, 3.65 mm (±0.48, 4.16 mm (±0.47, 1.14 (±0.04, 1.51 mm2 (±0.23, and 38.42 μL (±4.91 for pupillary radius, RICe, SSL-to-PM, AISL, ICR, iris cross-sectional area, and iris volume, respectively. Both pupillary radius (P = 0.002 and RICe (P = 0.027 decreased with age, while SSL-to-PM (P = 0.002 and AISL increased with age (P = 0.001. ICR (P = 0.54 and iris volume (P = 0.49 were not affected by age.This study establishes reference values for iris-related parameters in an adult open angle population, which will be useful for future studies examining the role of iris changes in pathologic states.

  9. About Connections

    Directory of Open Access Journals (Sweden)

    Kathleen S Rockland

    2015-05-01

    Full Text Available Despite the attention attracted by connectomics, one can lose sight of the very real questions concerning What are connections? In the neuroimaging community, structural connectivity is ground truth and underlying constraint on functional or effective connectivity. It is referenced to underlying anatomy; but, as increasingly remarked, there is a large gap between the wealth of human brain mapping and the relatively scant data on actual anatomical connectivity. Moreover, connections have typically been discussed as pairwise, point x projecting to point y (or: to points y and z, or more recently, in graph theoretical terms, as nodes or regions and the interconnecting edges. This is a convenient shorthand, but tends not to capture the richness and nuance of basic anatomical properties as identified in the classic tradition of tracer studies. The present short review accordingly revisits connectional weights, heterogeneity, reciprocity, topography, and hierarchical organization, drawing on concrete examples. The emphasis is on presynaptic long-distance connections, motivated by the intention to probe current assumptions and promote discussions about further progress and synthesis.

  10. Fibre-optic communications

    CERN Document Server

    Lecoy, Pierre

    2010-01-01

    This book describes in a comprehensive manner the components and systems of fiber optic communications and networks. The first section explains the theory of multimode and single-mode fibers, then the technological features, including manufacturing, cabling, and connecting. The second section describes the various components (passive and active optical components, integrated optics, opto-electronic transmitters and receivers, and optical amplifiers) used in fiber optic systems. Finally, the optical transmission system design is explained, and applications to optical networks and fiber optic se

  11. Order and chaos in polarized nonlinear optics

    International Nuclear Information System (INIS)

    Holm, D.D.

    1990-01-01

    Methods for investigating temporal complexity in Hamiltonian systems are applied to the dynamics of a polarized optical laser beam propagating as a travelling wave in a medium with cubically nonlinear polarizability (i.e., a Kerr medium). The theory of Hamiltonian systems with symmetry is used to study the geometry of phase space for the optical problem, transforming from C 2 to S 2 x (J,θ), where (J,θ) is a symplectic action-angle pair. The bifurcations of the phase portraits of the Hamiltonian motion on S 2 are classified and shown graphically. These bifurcations create various saddle connections on S 2 as either J (the beam intensity), or the optical parameters of the medium are varied. After this bifurcation analysis, the Melnikov method is used to demonstrate analytically that the saddle connections break and intersect transversely in a Poincare map under spatially periodic perturbations of the optical parameters of the medium. These transverse intersections in the Poincare map imply intermittent polarization switching with extreme sensitivity to initial conditions characterized by a Smale horseshoe construction for the travelling waves of a polarized optical laser pulse. The resulting chaotic behavior in the form of sensitive dependence on initial conditions may have implications for the control and predictability of nonlinear optical polarization switching in birefringent media. 19 refs., 2 figs., 1 tab

  12. Internet Connectivity

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Internet Connectivity. BSNL, SIFY, HCL in Guwahati; only BSNL elsewhere in NE (local player in Shillong). Service poor; All vendors lease BW from BSNL.

  13. Mathematics Connection

    African Journals Online (AJOL)

    MATHEMATICS CONNECTION aims at providing a forum topromote the development of Mathematics Education in Ghana. Articles that seekto enhance the teaching and/or learning of mathematics at all levels of theeducational system are welcome.

  14. HR Connect

    Data.gov (United States)

    US Agency for International Development — HR Connect is the USAID HR personnel system which allows HR professionals to process HR actions related to employee's personal and position information. This system...

  15. The use of polarized deuterons beams and the determination of the optical model parameters; Utilisation de faisceaux de deutons polarises et determination des parametres du modele optique

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-06-15

    A general description of beams of polarized particles in nuclear reactions is studied; the various choices necessary to define the polarization parameters are discussed with regard to their consequences. The frequent occurrence of symmetry plane yields a set of relations among these parameters. The range of these parameters is studied in particular for a beam of particles of spin 1 and with a symmetry plane. Nuclear reactions involving two bodies are described in terms of the helicity formalism. With the use of the adopted set of polarization parameters, the polarization of the final state is studied for a given polarization in the initial state. An optical model for deuterons may consist of a scalar term, an L.S potential and tensor potentials built with the distance between the deuteron and the nucleus, its angular momentum or its relative momentum. Calculations have been made with the first two tensor potentials. Many authors have calculated a potential for deuterons starting from the nucleon-nucleus potential. These calculations are redone taking into account both the S and D waves of the deuteron. The various terms of the potential have been calculated with a set of different intrinsic wave functions. The use of a potential not limited to scalar form yields good fits for cross-sections with nuclear radii which are greater than those necessary with a purely central potential. The experimental results obtained at Saclay for the polarization of deuterons elastically scattered by Ca are not compatible with the existence of an important tensor potential; they can be accounted for by an L.S coupling potential independent of the central potential but with very small radii. (author) [French] La description de faisceaux do particules polarisees dans les reactions nucleaires est etudiee de facon generale; les choix necessaires pour definir les parametres de polarisation sont discutes en fonction de leurs consequences. L'existence tres frequente d'un plan de symetrie

  16. Optical computer switching network

    Science.gov (United States)

    Clymer, B.; Collins, S. A., Jr.

    1985-01-01

    The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

  17. Optical constants, dispersion energy parameters and dielectric properties of ultra-smooth nanocrystalline BiVO4 thin films prepared by rf-magnetron sputtering

    Science.gov (United States)

    Sarkar, S.; Das, N. S.; Chattopadhyay, K. K.

    2014-07-01

    BiVO4 thin films have been prepared through radio frequency (rf) magnetron sputtering of a pre-fabricated BiVO4 target on ITO coated glass (ITO-glass) substrate and bare glass substrates. BiVO4 target material was prepared through solid-state reaction method by heating Bi2O3 and V2O5 mixture at 800 °C for 8 h. The films were characterized by X-ray diffraction, UV-Vis spectroscopy, LCR meter, field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. BiVO4 thin films deposited on the ITO-glass substrate are much smoother compared to the thin films prepared on bare glass substrate. The rms surface roughness calculated from the AFM images comes out to be 0.74 nm and 4.2 nm for the films deposited on the ITO-glass substrate and bare glass substrate for the deposition time 150 min respectively. Optical constants and energy dispersion parameters of these extra-smooth BiVO4 thin films have been investigated in detail. Dielectric properties of the BiVO4 thin films on ITO-glass substrate were also investigated. The frequency dependence of dielectric constant of the BiVO4 thin films has been measured in the frequency range from 20 Hz to 2 MHz. It was found that the dielectric constant increased from 145 to 343 at 20 Hz as the film thickness increased from 90 nm to 145 nm (deposition time increased from 60 min to 150 min). It shows higher dielectric constant compared to the literature value of BiVO4.

  18. Effect of concentration of dispersed organic matter on optical maturity parameters. Interlaboratory results of the organic matter concentration working group of the ICCP

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca Filho, J.G.; Kern, M.L.; Mendonca, J.O. [Palynofacies and Organic Facies Laboratory (LAFO), DEGL, IGEO, UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil); Araujo, C.V.; Menezes, T.R.; Souza, I.V.A.F. [Petrobras R and D Center, Rio de Janeiro (Brazil); Borrego, A.G.; Suarez-Ruiz, I. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain); Cook, A.; Ranasinghe, P. [Keiraville Konsultants Pty. Ltd, NSW (Australia); Flores, D. [University of Porto, Departamento de Geologia (Portugal); Hackley, P. [U.S. Geological Survey, MS 956 National Center Reston, VA (United States); Hower, J.C. [University of Kentucky, Center for Applied Energy Research, Lexington (United States); Kommeren, K. [Shell International Exploration and Production, Rijswijk (Netherlands); Kus, J. [Germany Federal Institute for Geosciences and Natural Resources in Geozentrum, Hannover (Germany); Mastalerz, M. [Indiana Geological Survey, Indiana University, Bloomington (United States); Newman, J. [Newman Energy Research Ltd, Christchurch (New Zealand); Ujiie, Y. [Graduate School of Science and Technology, Hirosaki University (Japan)

    2010-12-01

    The main objective of this work was to study the effect of the kerogen isolation procedures on maturity parameters of organic matter using optical microscopes. This work represents the results of the Organic Matter Concentration Working Group (OMCWG) of the International Committee for Coal and Organic Petrology (ICCP) during the years 2008 and 2009. Four samples have been analysed covering a range of maturity (low and moderate) and terrestrial and marine geological settings. The analyses comprise random vitrinite reflectance measured on both kerogen concentrate and whole rock mounts and fluorescence spectra taken on alginite. Eighteen participants from twelve laboratories from all over the world performed the analyses. Samples of continental settings contained enough vitrinite for participants to record around 50 measurements whereas fewer readings were taken on samples from marine setting. The scatter of results was also larger in the samples of marine origin. Similar vitrinite reflectance values were in general recorded in the whole rock and in the kerogen concentrate. The small deviations of the trend cannot be attributed to the acid treatment involved in kerogen isolation but to reasons related to components identification or to the difficulty to achieve a good polish of samples with high mineral matter content. In samples difficult to polish, vitrinite reflectance was measured on whole rock tended to be lower. The presence or absence of rock fabric affected the selection of the vitrinite population for measurement and this also had an influence in the average value reported and in the scatter of the results. Slightly lower standard deviations were reported for the analyses run on kerogen concentrates. Considering the spectral fluorescence results, it was observed that the {lambda}max presents a shift to higher wavelengths in the kerogen concentrate sample in comparison to the whole-rock sample, thus revealing an influence of preparation methods (acid treatment

  19. Comb-like optical transmission spectra generated from one-dimensional two-segment-connected two-material waveguide networks optimized by genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Yang, Xiangbo, E-mail: xbyang@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006 (China); Lu, Jian; Zhang, Guogang [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Liu, Chengyi Timon [School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006 (China)

    2014-03-01

    In this Letter, a one-dimensional (1D) two-segment-connected two-material waveguide network (TSCTMWN) is designed to produce comb-like frequency passbands, where each waveguide segment is composed of normal and anomalous dispersion materials and the length ratio of sub-waveguide segments is optimized by genetic algorithm (GA). It is found that 66 comb-like frequency passbands are created in the second frequency unit, maximal relative width difference of which is less than 2×10{sup −5}. It may be useful for the designing of dense wavelength division multiplexings (DWDMs) and multi-channel filters, etc., and provide new applications for GA.

  20. Establishing Connectivity

    DEFF Research Database (Denmark)

    Kjær, Poul F.

    Global law settings are characterised by a structural pre-eminence of connectivity norms, a type of norm which differs from coherency or possibility norms. The centrality of connectivity norms emerges from the function of global law, which is to increase the probability of transfers of condensed ...... and human rights can be understood as serving a constitutionalising function aimed at stabilising and facilitating connectivity. This allows for an understanding of colonialism and contemporary global governance as functional, but not as normative, equivalents.......Global law settings are characterised by a structural pre-eminence of connectivity norms, a type of norm which differs from coherency or possibility norms. The centrality of connectivity norms emerges from the function of global law, which is to increase the probability of transfers of condensed...... social components, such as economic capital and products, religious doctrines and scientific knowledge, from one legally structured context to another within world society. This was the case from colonialism and colonial law to contemporary global supply chains and human rights. Both colonial law...

  1. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-01

    The Connected Traveler framework seeks to boost the energy efficiency of personal travel and the overall transportation system by maximizing the accuracy of predicted traveler behavior in response to real-time feedback and incentives. It is anticipated that this approach will establish a feedback loop that 'learns' traveler preferences and customizes incentives to meet or exceed energy efficiency targets by empowering individual travelers with information needed to make energy-efficient choices and reducing the complexity required to validate transportation system energy savings. This handout provides an overview of NREL's Connected Traveler project, including graphics, milestones, and contact information.

  2. Optical XOR gate

    Science.gov (United States)

    Vawter, G. Allen

    2013-11-12

    An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  3. Fiber optic connector

    Science.gov (United States)

    Rajic, Slobodan; Muhs, Jeffrey D.

    1996-01-01

    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled.

  4. Making connections

    NARCIS (Netherlands)

    Marion Duimel

    2007-01-01

    Original title: Verbinding maken; senioren en internet. More and more older people are finding their way to the Internet. Many people aged over 50 who have only recently gone online say that a new world has opened up for them. By connecting to the Internet they have the feeling that they

  5. CMS Connect

    Science.gov (United States)

    Balcas, J.; Bockelman, B.; Gardner, R., Jr.; Hurtado Anampa, K.; Jayatilaka, B.; Aftab Khan, F.; Lannon, K.; Larson, K.; Letts, J.; Marra Da Silva, J.; Mascheroni, M.; Mason, D.; Perez-Calero Yzquierdo, A.; Tiradani, A.

    2017-10-01

    The CMS experiment collects and analyzes large amounts of data coming from high energy particle collisions produced by the Large Hadron Collider (LHC) at CERN. This involves a huge amount of real and simulated data processing that needs to be handled in batch-oriented platforms. The CMS Global Pool of computing resources provide +100K dedicated CPU cores and another 50K to 100K CPU cores from opportunistic resources for these kind of tasks and even though production and event processing analysis workflows are already managed by existing tools, there is still a lack of support to submit final stage condor-like analysis jobs familiar to Tier-3 or local Computing Facilities users into these distributed resources in an integrated (with other CMS services) and friendly way. CMS Connect is a set of computing tools and services designed to augment existing services in the CMS Physics community focusing on these kind of condor analysis jobs. It is based on the CI-Connect platform developed by the Open Science Grid and uses the CMS GlideInWMS infrastructure to transparently plug CMS global grid resources into a virtual pool accessed via a single submission machine. This paper describes the specific developments and deployment of CMS Connect beyond the CI-Connect platform in order to integrate the service with CMS specific needs, including specific Site submission, accounting of jobs and automated reporting to standard CMS monitoring resources in an effortless way to their users.

  6. Combined Multi-Temporal Optical and Radar Parameters for Estimating LAI and Biomass in Winter Wheat Using HJ and RADARSAR-2 Data

    Directory of Open Access Journals (Sweden)

    Xiuliang Jin

    2015-10-01

    Full Text Available Leaf area index (LAI and biomass are frequently used target variables for agricultural and ecological remote sensing applications. Ground measurements of winter wheat LAI and biomass were made from March to May 2014 in the Yangling district, Shaanxi, Northwest China. The corresponding remotely sensed data were obtained from the earth-observation satellites Huanjing (HJ and RADARSAT-2. The objectives of this study were (1 to investigate the relationships of LAI and biomass with several optical spectral vegetation indices (OSVIs and radar polarimetric parameters (RPPs, (2 to estimate LAI and biomass with combined OSVIs and RPPs (the product of OSVIs and RPPs (COSVI-RPPs, (3 to use multiple stepwise regression (MSR and partial least squares regression (PLSR to test and compare the estimations of LAI and biomass in winter wheat, respectively. The results showed that LAI and biomass were highly correlated with several OSVIs (the enhanced vegetation index (EVI and modified triangular vegetation index 2 (MTVI2 and RPPs (the radar vegetation index (RVI and double-bounce eigenvalue relative difference (DERD. The product of MTVI2 and DERD (R2 = 0.67 and RMSE = 0.68, p < 0.01 and that of MTVI2 and RVI (R2 = 0. 68 and RMSE = 0.65, p < 0.01 were strongly related to LAI, and the product of the optimized soil adjusted vegetation index (OSAVI and DERD (R2 = 0.79 and RMSE = 148.65 g/m2, p < 0.01 and that of EVI and RVI (R2 = 0. 80 and RMSE = 146.33 g/m2, p < 0.01 were highly correlated with biomass. The estimation accuracy of LAI and biomass was better using the COSVI-RPPs than using the OSVIs and RPPs alone. The results revealed that the PLSR regression equation better estimated LAI and biomass than the MSR regression equation based on all the COSVI-RPPs, OSVIs, and RPPs. Our results indicated that the COSVI-RPPs can be used to robustly estimate LAI and biomass. This study may provide a guideline for improving the estimations of LAI and biomass of winter wheat

  7. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Aerosol Optical Thickness (AOT) and Aerosol Particle Size Parameter (APSP) Environmental Data Record (EDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of Aerosol Optical Thickness (AOT) from the Visible Infrared Imaging Radiometer...

  8. Connectivity and superconductivity

    CERN Document Server

    Rubinstein, Jacob

    2000-01-01

    The motto of connectivity and superconductivity is that the solutions of the Ginzburg--Landau equations are qualitatively influenced by the topology of the boundaries, as in multiply-connected samples. Special attention is paid to the "zero set", the set of the positions (also known as "quantum vortices") where the order parameter vanishes. The effects considered here usually become important in the regime where the coherence length is of the order of the dimensions of the sample. It takes the intuition of physicists and the awareness of mathematicians to find these new effects. In connectivity and superconductivity, theoretical and experimental physicists are brought together with pure and applied mathematicians to review these surprising results. This volume is intended to serve as a reference book for graduate students and researchers in physics or mathematics interested in superconductivity, or in the Schrödinger equation as a limiting case of the Ginzburg--Landau equations.

  9. Gendered Connections

    DEFF Research Database (Denmark)

    Jensen, Steffen Bo

    2009-01-01

    This article explores the gendered nature of urban politics in Cape Town by focusing on a group of female, township politicians. Employing the Deleuzian concept of `wild connectivity', it argues that these politically entrepreneurial women were able to negotiate a highly volatile urban landscape...... by drawing on and operationalizing violent, male networks — from struggle activists' networks, to vigilante groups and gangs, to the police. The fact that they were women helped them to tap into and exploit these networks. At the same time, they were restricted by their sex, as their ability to navigate...... space also drew on quite traditional notions of female respectability. Furthermore, the article argues, the form of wild connectivity to an extent was a function of the political transition, which destabilized formal structures of gendered authority. It remains a question whether this form...

  10. The Berry's connection

    International Nuclear Information System (INIS)

    Le Tourneux, J.

    1989-01-01

    A course on the Berry's connection is presented. The main steps leading to the Berry's discovery are reviewed and the obtained equations are examined. Some applications of Berry's formulation are presented. They include diatomic molecules, dipole-quadrupole interaction in spherical mucleus and diabolic pair transfer. The experimental results presented are the spectrum of the Na 3 molecule, the propagation of photons in an helical optical fiber and the neutron spin rotation. Non-abelian problems and the Aharonow-Anandan phase are discussed [fr

  11. Accuracy in Optical Information Processing

    Science.gov (United States)

    Timucin, Dogan Aslan

    Low computational accuracy is an important obstacle for optical processors which blocks their way to becoming a practical reality and a serious challenger for classical computing paradigms. This research presents a comprehensive solution approach to the problem of accuracy enhancement in discrete analog optical information processing systems. Statistical analysis of a generic three-plane optical processor is carried out first, taking into account the effects of diffraction, interchannel crosstalk, and background radiation. Noise sources included in the analysis are photon, excitation, and emission fluctuations in the source array, transmission and polarization fluctuations in the modulator, and photoelectron, gain, dark, shot, and thermal noise in the detector array. Means and mutual coherence and probability density functions are derived for both optical and electrical output signals. Next, statistical models for a number of popular optoelectronic devices are studied. Specific devices considered here are light-emitting and laser diode sources, an ideal noiseless modulator and a Gaussian random-amplitude-transmittance modulator, p-i-n and avalanche photodiode detectors followed by electronic postprocessing, and ideal free-space geometrical -optics propagation and single-lens imaging systems. Output signal statistics are determined for various interesting device combinations by inserting these models into the general formalism. Finally, based on these special-case output statistics, results on accuracy limitations and enhancement in optical processors are presented. Here, starting with the formulation of the accuracy enhancement problem as (1) an optimal detection problem and (2) as a parameter estimation problem, the potential accuracy improvements achievable via the classical multiple-hypothesis -testing and maximum likelihood and Bayesian parameter estimation methods are demonstrated. Merits of using proper normalizing transforms which can potentially stabilize

  12. Cosmic Connections

    CERN Document Server

    Ellis, Jonathan Richard

    2003-01-01

    A National Research Council study on connecting quarks with the cosmos has recently posed a number of the more important open questions at the interface between particle physics and cosmology. These questions include the nature of dark matter and dark energy, how the Universe began, modifications to gravity, the effects of neutrinos on the Universe, how cosmic accelerators work, and whether there are new states of matter at high density and pressure. These questions are discussed in the context of the talks presented at this Summer Institute.

  13. Electronic structure optical spectra and contact hyperfine parameters of CoF64- complex in LiF and KMgF3

    International Nuclear Information System (INIS)

    Albuquerque, E.L. de.

    1975-12-01

    The electronic structure, the optical absorption bands and the magnetic hyperfine contact terms have been calculated for CoF 6 4- cluster in LiF and KMgF 3 using the Self-Consistent-Field Multiple-Scattering Xα Method. The results obtained are compared with experiment and indicate that this scheme is convenient to treat such complex problems. (Author) [pt

  14. Magneto-optical and electromagnetic studies of core connectivity and weak-link behaviour in Cu/MgB2 and Ni/MgB2 wires and tapes

    International Nuclear Information System (INIS)

    Polyanskii, A; Beilin, V; Felner, I; Tsindlekht, M I; Yashchin, E; Dul'kin, E; Galstyan, E; Roth, M; Senkowicz, B; Hellstrom, E

    2004-01-01

    Critical current density, ac susceptibility (real part χ' and magneto-optical (MO) imaging were used to characterize round wire and tapes made from pre-reacted MgB 2 powder by the powder-in-tube method. Magnetic susceptibility measurements indicated the existence of large-scale weak-link networks in the cores of as-deformed Ni/MgB 2 and Cu/MgB 2 wires and tapes. As-deformed samples showed a two-step transition in χ' versus T traces as evidence of weak links in the tape core. The first heat treatment (HT) of as-deformed tapes led to a sharp susceptibility transition, very strong connection in the tape core as seen in MO images, and high critical current. A second rolling of an as-sintered tape induced a network of defects in the brittle core and gave rise to χ' curve broadening, but did not result in a two-step transition. These data show that deformation-induced cracks are not the primary source of weak-link behaviour. A large decrease in transport current was also registered in this sample. The second HT, for 30 min, restored the sharp magnetic transition and high transport current. Alternating areas of strong and weak connection in the tape core have been observed on MO images. Fast heating and cooling of the as-deformed tape with no dwell time at the maximum temperature resulted in a strongly linked core with a sharp transition and increased transport current. After fast HT, no mechanical defects were observed in MO images. Such fast transformation could be explained by rapid sintering due to highly strained MgB 2 grains

  15. Optics/Optical Diagnostics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Optics/Optical Diagnostics Laboratory supports graduate instruction in optics, optical and laser diagnostics and electro-optics. The optics laboratory provides...

  16. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  17. Places Connected:

    DEFF Research Database (Denmark)

    Hansen, Annette Skovsted

    This paper argues that development assistance contributed to the globalization of the 20th century by financing truly global networks of people. By focusing on the networks financed by development assistance bound by the national histories of Denmark and Japan, I illustrate how the people who...... experiences of place, however, when it is often the same people who experience many different places? Along with many other so-called donors in the 1950s, Denmark and Japan chose to invest in the education of own and other nationals involved in development and thereby financed personal connections between...... individuals throughout the world. Development assistance , where there are two or three links only between a Bangladeshi farmer, a street child in Sao Paolo and the President of the United States, the Queen of Denmark, or a suburban house wife in Japan, who has never left the Osaka area, but mothered a United...

  18. Optical parameters of ITO/TPD/Alq3/Al luminescent structures, containing arrays of CdSe/ZnS colloidal quantum dots

    Science.gov (United States)

    Mikhailov, I. I.; Tarasov, S. A.; Lamkin, I. A.; Tadtaev, P. O.; Kozlovich, L. I.; Solomonov, A. V.; Stepanov, E. M.

    2016-08-01

    The luminescent organic ITO/TPD/Alq3/Al structures and CdSe/ZnS quantum dots (QD) arrays were created. Electrical and optical properties of the samples were examined. The luminescence of the layers and QD arrays was shown in the range of wavelengths from 400 to 680 nm. Luminescent structures with phosphors corresponding to the emission standards with CRI>98 and with color temperature of 5500 K and 6504 K were created.

  19. Effect of Co doping concentration on structural properties and optical parameters of Co-doped ZnO thin films by sol-gel dip-coating method.

    Science.gov (United States)

    Nam, Giwoong; Yoon, Hyunsik; Kim, Byunggu; Lee, Dong-Yul; Kim, Jong Su; Leem, Jae-Young

    2014-11-01

    The structural and optical properties of Co-doped ZnO thin films prepared by a sol-gel dip-coating method were investigated. X-ray diffraction analysis showed that the thin films were grown with a c-axis preferred orientation. The position of the (002) peak was almost the same in all samples, irrespective of the Co concentration. It is thus clear that Co doping had little effect on the position of the (002) peak. To confirm that Co2+ was substituted for Zn2+ in the wurtzite structure, optical measurements were conducted at room temperature by a UV-visible spectrometer. Three absorption peaks are apparent in the Co-doped ZnO thin films that do not appear for the undoped ZnO thin film. As the Co concentration was increased, absorption related to characteristic Co2+ transitions increased because three absorption band intensities and the area underneath the absorption wells between 500 and 700 nm increased with increasing Co concentration. The optical band gap and static dielectric constant decreased and the Urbach energy and extinction coefficient increased with increasing Co concentration.

  20. Offloading IP Flows onto Lambda-Connections

    NARCIS (Netherlands)

    Fioreze, Tiago; Oude Wolbers, Mattijs; van de Meent, R.; Pras, Aiko

    2007-01-01

    Optical networks are capable of switching IP traffic via lambda connections. In this way, big IP flows that overload the regular IP routing level may be moved to the optical level, where they get better Quality of Service (QoS). At the same time, the IP routing level is off-loaded and can serve

  1. Optical memory

    Science.gov (United States)

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  2. Optical Spectroscopy

    DEFF Research Database (Denmark)

    Thyrhaug, Erling

    The work presented in this thesis is broadly concerned with how complexation reactions and molecular motion can be characterized with the standard techniques in optical spectroscopy. The thesis aims to show a relatively broad range of methods for probing physico-chemical properties in fluorophore...... information about chemical equilibria, kinetics and molecular motion by monitoring changes in optical properties of the system. The five presented research projects are largely unrelated to each other both in aim and in what property is probed, however they are all connected in that they are fluorophore...... reactions by optical spectroscopy. In project 1 simple steady-state absorption and fluorescence spectroscopy is used to determine the stoichiometries and equilibrium constants in the inclusion complex formation between cyclodextrins and derivatives of the water-insoluble oligo(phenylene vinylene) in aqueous...

  3. Influence of composition on optical and dispersion parameters of thermally evaporated non-crystalline Cd{sub 50}S{sub 50−x}Se{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hassanien, A.S., E-mail: a.s.hassanien@gmail.com [Engineering Mathematics and Physics Dept., Faculty of Engineering (Shoubra), Benha University (Egypt); Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia); Akl, Alaa A. [Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia)

    2015-11-05

    Non-crystalline thin films of chalcogenide Cd{sub 50}S{sub 50−x}Se{sub x} system (30 ≤ x ≤ 50) were obtained by thermal evaporation technique onto a pre-cleaned glass substrate at a vacuum of 8.2 × 10{sup −4} Pa. The deposition rate and film thickness were kept constant at about 8 nm/s and 200 nm, respectively. Amorphous/crystalline nature and chemical composition of films have been checked using X-ray diffraction and energy dispersive X-ray spectroscopy (EDX). Optical properties of thin films were investigated and studied using the corrected transmittance, T(λ) and corrected reflectance, R(λ) measurements. Obtained data reveal that, the indirect optical energy gap (E{sub g}) was decreased from 2.21 to 1.57 eV. On the contrary, Urbach energy (band tail width), E{sub U} was found to be increased from 0.29 to 0.45 eV. This behavior is believed to be associated with the increase of Se-content instead of S-content in the thin films of Cd{sub 50}S{sub 50−x}Se{sub x} system. Chemical bond approach model, CBA was used to analyze the obtained values of E{sub g} and E{sub U}. Optical density, skin depth, extinction coefficient, refractive index and optical conductivity of chalcogenide CdSSe thin films were discussed as functions of Se-content. Using Wemple-DiDomenico single oscillator model, the refractive index dispersion and energy parameters and their dependence on Se content were studied. - Highlights: • Amorphous thin films of thickness 200 nm of Cd{sub 50}S{sub 50−x}Se{sub x} (30 ≤ x ≤ 50) have prepared. • Optical properties, indirect optical energy gap and band tail width were studied. • Chemical bond approach, CBA was used to analyze the obtained values of E{sub g} and E{sub U}. • New data of dispersion refractive index parameters were investigated and discussed.

  4. Routing and Disaster Awareness in Optical Networks

    NARCIS (Netherlands)

    Muhammad Iqbal, M.A.F.

    2016-01-01

    Optical networks facilitate the configurations of high-speed network connections with tremendous bandwidth between the optical switches. Optical switches are interconnected by optical fibers that act as the mediums in which data are transferred using lightpaths. Due to the importance of optical

  5. Determination of optical constant and dispersion parameters of Se{sub 75}Sb{sub 10}In{sub 15} thin film characterized by wide band gap

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Elrahman, M.I.; Abu-Sehly, A.A.; El-sonbaty, Sherouk Sh.; Hafiz, M.M. [Assiut University, Physics Department, Faculty of Science, Assiut (Egypt)

    2017-02-15

    Chalcogenide Se{sub 75}Sb{sub 10}In{sub 15} thin films of different thickness (50-300 nm) are deposited using thermal evaporation technique. The thermogram of the chalcogenide bulk Se{sub 75}Sb{sub 10}In{sub 15} is obtained using a differential scanning calorimetry (DSC). The crystallization temperature T{sub c}, peak crystallization temperature T{sub p} and melting temperature T{sub m}, are identified. The X-ray diffraction (XRD) examination indicates the crystallinity of the as-deposited film decreases with increasing of thickness. Optical transmission and reflection spectra are recorded in the wavelength range of the incident photons from 250 to 2500 nm. It is found that the film thickness affects the absorption coefficient, refractive index, extinction coefficient and the width of the tails of localized states in the gap region. The absorption mechanism of the as-deposited films is a direct allowed transition. The optical band gap energy (E{sub g}) decreases from 3.31 to 2.51 eV with increasing the film thickness from 50 to 300 nm. The behavior of E{sub g} is explained on the basis of the structure disorders in the thicker films. The effect of the film thickness on the single-oscillator and dispersion energies is studied by the dispersion analyses of the refractive index. (orig.)

  6. Optical loss analysis and parameter optimization for fan-shaped single-polarization grating coupler at wavelength of 1.3 µm band

    Science.gov (United States)

    Ushida, Jun; Tokushima, Masatoshi; Sobu, Yohei; Shimura, Daisuke; Yashiki, Kenichiro; Takahashi, Shigeki; Kurata, Kazuhiko

    2018-05-01

    Fan-shaped grating couplers (F-GCs) can be smaller than straight ones but are less efficient in general in coupling to single-mode fibers. To find a small F-GC with sufficiently high fiber-coupling characteristics, we numerically compared the dependencies of coupling efficiencies on wavelengths, the starting width of gratings, and misalignment distances among 25, 45, and 60° tapered angles of fan shape by using the three-dimensional finite-difference time domain method. A F-GC with a tapered angle of 25° exhibited the highest performances for all dependencies. The optical loss origins of F-GCs were discussed in terms of the electric field structures in them and scattering at the joint between the fan-shaped slab and channel waveguide. We fabricated an optimized 25° F-GC by using ArF photolithography, which almost exactly reproduced the optical coupling efficiency and radiation angle characteristics that were numerically expected.

  7. Fiber-optic control system for LAE 10 accelerator and pulse radiolysis experimental set

    International Nuclear Information System (INIS)

    Dzwigalski, Z.; Zimek, Z.

    2006-01-01

    The LAE 10 accelerator is used in nanosecond pulse radiolysis experiments as a source of 10 ns pulses of high energy electrons. The accelerator system was elaborated in the years 1991-1993. Inseparable connections of the optical fiber marrow with E/O and O/E converters (executed in welding technique) ensured a high stability of the optical parameters at a very long time. The preparation of connections needed adoption of expensive instrumentation from an optoelectronic laboratory in Warsaw. In presented paper authors describe their own action to improve operation of the LAE 10 accelerator existing in the Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

  8. Optical Multidimensional Switching for Data Center Networks

    OpenAIRE

    Kamchevska, Valerija; Galili, Michael; Oxenløwe, Leif Katsuo; Berger, Michael Stübert

    2017-01-01

    Optical switches are known for the ability to provide high bandwidth connectivity at a relatively low power consumption and low latency. Several recent demonstrations on optical data center architectures confirm the potential for introducing all-optical switching within the data center, thus avoiding power hungry optical-electrical-optical conversions at each node. This Ph.D. thesis focuses precisely on the application of optical technologies in data center networks where optics is not only u...

  9. Influence of the spray pyrolysis seeding and growth parameters on the structure and optical properties of ZnO nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Juan, E-mail: jrodriguez@uni.edu.pe [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31 (Peru); Feuillet, Guy [CEA Grenoble/LETI, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Donatini, Fabrice [Univ. Grenoble Alpes, Inst NEEL, F-38000 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Onna, Diego [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Sanchez, Luis [Facultad de Ciencias, Universidad Nacional de Ingeniería, P.O. Box 31-139, Lima 31 (Peru); Candal, Roberto [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); ECyT, 3iA, Universidad Nacional de San Martín, Martín de Irigoyen N° 3100 (1650), San Martín, Pcia de Buenos Aires (Argentina); Marchi, M. Claudia [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); CMA, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina); Bilmes, Sara A. [DQIAQF-INQUIMAE, FCEyN-Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, 1428 Buenos Aires (Argentina); Chandezon, Frédéric [University Grenoble Alpes, INAC-SPRAM, F-38000 Grenoble (France); CNRS, INAC-SPRAM, F-38000 Grenoble (France); CEA, INAC-SPRAM, F-38000 Grenoble (France)

    2015-02-01

    ZnO nanorods (NRs) were grown on fluorine doped tin oxide (FTO) substrates at low temperatures (90 °C) from Zn{sup 2+} precursors in alkaline media previously seeded with ZnO nanoparticles. These were deposited onto the FTO substrate heated at 350 °C by spray pyrolysis of a Zn acetate solution in a water ethanol mixture. The structure of seeds was tuned by the ethanol to water ratio, Γ, which controls the solvent evaporation rate of drops impinging the substrate. From a detailed characterization using a combination of scanning electron microscopy, X-ray diffraction, UV–visible absorption and cathodoluminescence spectroscopies, the dependence of the morphology and optical properties of the ZnO NRs on the seeding conditions was demonstrated. NRs grown on seeds deposited from solutions with Γ in the 0.03–0.06 range – i.e. when the surface excess of ethanol in the water–ethanol mixture has a maximum – show thinner average diameters and stacking faults due to the presence of zinc blende domains embedded into an overall wurtzite NR. They furthermore exhibit blue-shifted near band edge emission peak and a high deep level emission in cathodoluminescence. All these findings support the use of spray pyrolysis as a simple and reproducible way to control the seeds deposition, influencing the growth, the structure and the optical properties of the final ZnO NRs. - Highlights: • ZnO pyrolytic seeds tuned by the rate of solvent evaporation. • ZnO NRs grown from tuned pyrolytic seed's structure shows diameter dependence. • ZnO NRs show stacking faults due to the presence of zinc blende domains.

  10. Optical Ethernet

    Science.gov (United States)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-09-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. Scope of Submission The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities To submit to this special issue, follow the normal procedure for submission to JON, indicating "Optical Ethernet feature" in the "Comments" field of the online submission form. For all other questions

  11. Grouted Connections with Shear Keys

    DEFF Research Database (Denmark)

    Pedersen, Ronnie; Jørgensen, M. B.; Damkilde, Lars

    2012-01-01

    This paper presents a finite element model in the software package ABAQUS in which a reliable analysis of grouted pile-to-sleeve connections with shear keys is the particular purpose. The model is calibrated to experimental results and a consistent set of input parameters is estimated so that dif...... that different structural problems can be reproduced successfully....

  12. On observation of the downconversion mechanism in Er{sup 3+}/Yb{sup 3+} co-doped tellurite glass using thermal and optical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, M.S.; Santos, F.A. [Universidade Federal da Grande Dourados, Faculdade de Ciências Exatas e Tecnologias, Dourados, MS (Brazil); Yukimitu, K.; Moraes, J.C.S. [Universidade Estadual Paulista, UNESP, Departamento de Física e Química, Av. Brasil, 56, 15385-000 Ilha Solteira, SP (Brazil); Nunes, L.A.O. [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP (Brazil); Andrade, L.H.C. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de Dourados, CP 351, Dourados, MS (Brazil); Lima, S.M., E-mail: smlima@uems.br [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de Dourados, CP 351, Dourados, MS (Brazil)

    2015-01-15

    In this work we report the observed downconversion (DC) mechanism in Er{sup 3+}/Yb{sup 3+}-codoped tellurite glasses (in mol%, 80TeO{sub 2}–10Li{sub 2}O–10TiO{sub 2}). The samples were synthesized by the conventional melt-quenching method and then studied using optical spectroscopy and thermal lens spectroscopy (TLS). These characterizations enabled investigation of the radiative and nonradiative processes involved in energy transfer from erbium to ytterbium. The visible Er{sup 3+} fluorescence intensities decreased as a function of the Yb{sup 3+} concentration, and there was a corresponding increase in the ytterbium emission at around 980 nm. Simultaneously, there was a reduction in the heat-generated due nonradiative decays (∼21%) when ytterbium was added. This temperature change was measured by TLS measurements and the results corroborate with the indicated by spectroscopic interpretation. - Highlights: • Energy transfer from erbium to ytterbium in tellurite glass. • ∼56% of cross-relaxation efficiency from Er{sup 3+} to Yb{sup 3+}. • Downconversion effect in tellurite glasses. • Downconversion effect observation by thermal lens spectroscopy.

  13. GA BASED GLOBAL OPTIMAL DESIGN PARAMETERS FOR ...

    African Journals Online (AJOL)

    Journal of Modeling, Design and Management of Engineering Systems ... DESIGN PARAMETERS FOR CONSECUTIVE REACTIONS IN SERIALLY CONNECTED ... for the process equipments such as chemical reactors used in industries.

  14. Optical materials

    International Nuclear Information System (INIS)

    Poker, D.B.; Ortiz, C.

    1989-01-01

    This book reports on: Diamond films, Synthesis of optical materials, Structure related optical properties, Radiation effects in optical materials, Characterization of optical materials, Deposition of optical thin films, and Optical fibers and waveguides

  15. InP/ZnS quantum-dot-dispersed nematic liquid crystal illustrating characteristic birefringence and enhanced electro-optical parameters

    Science.gov (United States)

    Roy, Aradhana; Pathak, Govind; Herman, Jakub; Inamdar, Sanjeev R.; Srivastava, Atul; Manohar, Rajiv

    2018-03-01

    The present study investigates the influence of InP/ZnS core/shell QDs on various parameters of Nematic LC sample 1832A, based on 4-(4-alkyl-cyclohexyl)benzene isothiocyanates and 4-(4-alkyl-cyclohexyl)biphenyl isothiocyanates. Observations recorded consist of distinguished functioning of birefringence phenomenon along with characteristic response time measurement. Further study of rotational viscosity and splay elastic constant portrays stupendous behavior strengthening the appositeness of the composites for low-charge consumable devices. The addition of 0.2 ml of core/shell QDs producing more than two times faster response and enhanced birefringence at low-temperature range can be employed in development of thermostable photonic devices. In addition, dielectric properties comprising of relative permittivity and conductivity have been reported supporting the outcome of the investigation in applicative LC-based technologies.

  16. Minimum cost connection networks

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tvede, Mich

    In the present paper we consider the allocation of cost in connection networks. Agents have connection demands in form of pairs of locations they want to be connected. Connections between locations are costly to build. The problem is to allocate costs of networks satisfying all connection demands...

  17. Fiber-Optic Monitoring System of Particle Counters

    Directory of Open Access Journals (Sweden)

    A. A. Titov

    2016-01-01

    Full Text Available The article considers development of a fiber-optic system to monitor the counters of particles. Presently, optical counters of particles, which are often arranged at considerable distance from each other, are used to study the saltation phenomenon. For monitoring the counters, can be used electric communication lines.However, it complicates and raises the price of system Therefore, we offered a fiber-optic system and the counter of particles, free from these shortcomings. The difference between the offered counter of particles and the known one is that the input of radiation to the counter and the output of radiation scattering on particles are made by the optical fibers, and direct radiation is entered the optical fiber rather than is delayed by a light trap and can be used for lighting the other counters thereby allowing to use their connection in series.The work involved a choice of the quartz multimode optical fiber for communication, defining the optical fiber and lenses parameters of the counter of particles, and a selection of the radiation source and the photo-detector.Using the theory of light diffraction on a particle, a measuring range of the particle sizes has been determined. The system speed has been estimated, and it has been shown that a range of communication can reach 200km.It should be noted that modulation noise of counters of particles connected in series have the impact on the useful signal. To assess the extent of this influence we have developed a calculation procedure to illustrate that with ten counters connected in series this influence on the signal-to-noise ratio will be insignificant.Thus, it has been shown that the offered fiber-optic system can be used for monitoring the counters of particles across the desertified territories. 

  18. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo

    2015-01-01

    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  19. Retrobulbar diameter of optic nerve in glaucoma

    Directory of Open Access Journals (Sweden)

    Stefanović Ivan

    2009-01-01

    Full Text Available Introduction. The ultrasound diagnostics of the optic nerve includes the analysis of the optic nerve disc (PNO and measuring of its retrobulbar diameter. With B-scan, by Schraeder's method, it is possible to measure very precisely the optic nerve, the pial diameter, the normal values for the pial diameter being 2.8-4.1 mm. In glaucoma, the disease that is most frequently associated with higher intraocular pressure, there comes the destruction of nerve fibres, which can be visualized as the excavation of the optic nerve disc. Objective. In this paper, we were interested in finding whether in glaucoma, and in what phase of the disease, the optic nerve starts growing thinner. Aware of many forms of this very complex disease, we were interested in knowing if the visualization of excavation on the optic nerve disc is related to diminishing of the pial diameter of the retrobulbar nerve part. Methods. There were treated the patients who had already had the diagnosis of glaucoma and the visualized excavation of the optic disc of various dimensions. Echographically, there was measured the thickness of the retrobulbar part of the optic nerve and the finding compared in relation to the excavation of the optic disc. Results. In all eyes with glaucoma, a normal size of the retrobulbar part of the optic nerve was measured, ranging from 3.01 to 3.91 mm with the median of 3.36 mm. Also, by testing the correlation between the thickness of the optic nerve and the excavation of the PNO, by Pearson test, we found that there was no correlation between these two parameters (r=0.109; p>0.05. Conclusion. In the patients with glaucoma, the retrobulbar part of the optic nerve is not thinner (it has normal values, even not in the cases with a totally excavated optic disc. There is no connection between the size of the PNO excavation and the thickness of the retrobulbar part of the optic nerve.

  20. Temperature studies of optical parameters of (Ag3AsS3)0.6(As2S3)0.4 thin films prepared by rapid thermal evaporation and pulse laser deposition

    Science.gov (United States)

    Studenyak, I. P.; Kutsyk, M. M.; Buchuk, M. Yu.; Rati, Y. Y.; Neimet, Yu. Yu.; Izai, V. Yu.; Kökényesi, S.; Nemec, P.

    2016-02-01

    (Ag3AsS3)0.6(As2S3)0.4 thin films were deposited using rapid thermal evaporation (RTE) and pulse laser deposition (PLD) techniques. Ag-enriched micrometre-sized cones (RTE) and bubbles (PLD) were observed on the thin film surface. Optical transmission spectra of the thin films were studied in the temperature range 77-300 K. The Urbach behaviour of the optical absorption edge in the thin films due to strong electron-phonon interaction was observed, the main parameters of the Urbach absorption edge were determined. Temperature dependences of the energy position of the exponential absorption edge and the Urbach energy are well described in the Einstein model. Dispersion and temperature dependences of refractive indices were analysed; a non-linear increase of the refractive indices with temperature was revealed. Disordering processes in the thin films were studied and compared with bulk composites, the differences between the thin films prepared by RTE and PLD were analysed.

  1. DISSECTING HABITAT CONNECTIVITY

    Science.gov (United States)

    abstractConnectivity is increasingly recognized as an important element of a successful reserve design. Connectivity matters in reserve design to the extent that it promotes or hinders the viability of target populations. While conceptually straightforward, connectivity i...

  2. Mixed Connective Tissue Disease

    Science.gov (United States)

    Mixed connective tissue disease Overview Mixed connective tissue disease has signs and symptoms of a combination of disorders — primarily lupus, scleroderma and polymyositis. For this reason, mixed connective tissue disease ...

  3. Undifferentiated Connective Tissue Disease

    Science.gov (United States)

    ... Home Conditions Undifferentiated Connective Tissue Disease (UCTD) Undifferentiated Connective Tissue Disease (UCTD) Make an Appointment Find a Doctor ... by Barbara Goldstein, MD (February 01, 2016) Undifferentiated connective tissue disease (UCTD) is a systemic autoimmune disease. This ...

  4. Intermodal Passenger Connectivity Database -

    Data.gov (United States)

    Department of Transportation — The Intermodal Passenger Connectivity Database (IPCD) is a nationwide data table of passenger transportation terminals, with data on the availability of connections...

  5. Parametric imaging of viscoelasticity using optical coherence elastography

    Science.gov (United States)

    Wijesinghe, Philip; McLaughlin, Robert A.; Sampson, David D.; Kennedy, Brendan F.

    2015-03-01

    We demonstrate imaging of soft tissue viscoelasticity using optical coherence elastography. Viscoelastic creep deformation is induced in tissue using step-like compressive loading and the resulting time-varying deformation is measured using phase-sensitive optical coherence tomography. From a series of co-located B-scans, we estimate the local strain rate as a function of time, and parameterize it using a four-parameter Kelvin-Voigt model of viscoelastic creep. The estimated viscoelastic strain and time constant are used to visualize viscoelastic creep in 2D, dual-parameter viscoelastograms. We demonstrate our technique on six silicone tissue-simulating phantoms spanning a range of viscoelastic parameters. As an example in soft tissue, we report viscoelastic contrast between muscle and connective tissue in fresh, ex vivo rat gastrocnemius muscle and mouse abdominal transection. Imaging viscoelastic creep deformation has the potential to provide complementary contrast to existing imaging modalities, and may provide greater insight into disease pathology.

  6. Formal connections in deformation quantization

    DEFF Research Database (Denmark)

    Masulli, Paolo

    The field of this thesis is deformation quantization, and we consider mainly symplectic manifolds equipped with a star product. After reviewing basics in complex geometry, we introduce quantization, focusing on geometric quantization and deformation quantization. The latter is defined as a star...... characteristic class, and that formal connections form an affine space over the derivations of the star products. Moreover, if the parameter space for the family of star products is contractible, we obtain that any two flat formal connections are gauge equivalent via a self-equivalence of the family of star...

  7. Finite connectivity attractor neural networks

    International Nuclear Information System (INIS)

    Wemmenhove, B; Coolen, A C C

    2003-01-01

    We study a family of diluted attractor neural networks with a finite average number of (symmetric) connections per neuron. As in finite connectivity spin glasses, their equilibrium properties are described by order parameter functions, for which we derive an integral equation in replica symmetric approximation. A bifurcation analysis of this equation reveals the locations of the paramagnetic to recall and paramagnetic to spin-glass transition lines in the phase diagram. The line separating the retrieval phase from the spin-glass phase is calculated at zero temperature. All phase transitions are found to be continuous

  8. Parameter Estimation

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian

    2011-01-01

    of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set......In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....

  9. Research and investigation of a communication chain on optical fiber with a Fabry-Perot power diode for the automotive industry

    Science.gov (United States)

    Bacis, Irina Bristena; Vasile, Alexandru; Ionescu, Ciprian; Marghescu, Cristina

    2016-12-01

    The purpose of this paper is to analyze different power devices - emitters of optical flow, from the point of view of optical coupling, emitted optical powers, optical fiber losses and receiver. The research and characterization of the transmission through a power optical system is done using a computer system specialized for the automotive industry. This system/platform can deliver current pulses that are controlled by a computer through a software (it is possible to set different parameters such as pulse repetition frequency, duty cycle, and current intensity). For the experiments a power Fabry Perot 1035 laser diode operating in pulse with μφ 1055 nm, Ith = 40 mA, and Iop =750 mA was used with a single-mode SFM 128 optical fiber and an EM type optical coupler connected through alignment. Two types of measurements were conducted to demonstrate the usefulness of the experimental structure. In the first case the amplitude of the voltage pulses was measured at the output of an optical detector with receiving diode in a built-in amplifier with a 50 kΩ load resistance. In the second stage measurements were conducted to determine the optical power injected in the optical fiber and received at the reception cell of a power meter. Another parameter of optical coupling that can be measured using the experimental structure is irradiation. This parameter is very important to determine the optimum cutting angle of the fiber for continuity welding.

  10. Optic neuritis

    Science.gov (United States)

    Retro-bulbar neuritis; Multiple sclerosis - optic neuritis; Optic nerve - optic neuritis ... The exact cause of optic neuritis is unknown. The optic nerve carries visual information from your eye to the brain. The nerve can swell when ...

  11. Optical gyroscope

    Science.gov (United States)

    Seifollahi, Alireza

    It is said that future of the world is based on space exploration which leads us to think more about low cost and light weight instruments. Cheap and sensitive instruments should be de-signed and replace the expensive ones. One of the required instruments in space ships is gyroscope controls the direction of space ship. In this article I am going to give an idea to use optical properties in a new gyroscope which will be cheaper as well as more sensitive in com-pare with most of the being used normal gyroscope nowadays. This instrument uses an optical system to measure the angular changes in the direction of a space craft movements in any of the three axels. Any movement, even very small one, will move a crystal bulb which is lashed by some narrow elastic bands in a fixed box surrounded by three optical sources and light meters. Light meters measure the attitude and the angel of changes in the light beams going through the bulb which is related to the amount of changes in the space craft directions. The system will be very sensitive even against movement around its access. As an electro digital device in connection to a Main Process Unit (MPU) it can be used in Stability Augmentation System (SAS) in a space ship. The sensitivity rate of the instrument will be based on the quality and sensitivity of the light meters.

  12. Radiation effects in optical components

    International Nuclear Information System (INIS)

    Friebele, E.J.

    1987-01-01

    This report discusses components of high performance optical devices may be exposed to high energy radiation environments during their lifetime. The effect of these adverse environments depends upon a large number of parameters associated with the radiation (nature, energy, dose, dose rate, etc.) or the system (temperature, optical performance requirements, optical wavelength, optical power, path length, etc.), as well as the intrinsic susceptibility of the optical component itself to degradation

  13. The Influence of Geometrical Parameters in Socket - Pin Connections on the Value of Opening Force / Wpływ Parametrów Geometrycznych W Połączeniach Typu Gniazdo - Trzpień Na Wartość Siły Otwierającej

    Directory of Open Access Journals (Sweden)

    Sadowski T.

    2015-12-01

    Full Text Available The paper presents an analysis of the influence of a number of technological aspects of both the socket and the pin on the value of the force required for joint disconnection. A number of numerical simulations were made in Abaqus program to examine effects of such parameters as: presence of an interference fit, use of spherical latches, application of different rigidity of the pin by making cuts with variable width and length, use of different angles of inclination of the working part of the connection. Models of different simple joints presented in this work, can also operate in large structures forming panels of aircraft structures. For this purpose one of the analyzed geometry of the connection was applied to create a 3-D panel model of the structural element in CAD - SolidWorks program. All analysed models with different geometries were subjected to simulation of opening process. The corresponding critical forces were estimated for the beginning of the failure process. The detailed discussion of all model parameters was included to specify their influence on the whole disconnection of joints. It should be noted that aerospace structures work under complex loading states and further numerical studies are required to extend the presented results.

  14. Nano-spatial parameters from 3D to 2D lattice dimensionality by organic variant in [ZnCl4]- [R]+ hybrid materials: Structure, architecture-lattice dimensionality, microscopy, optical Eg and PL correlations

    Science.gov (United States)

    Kumar, Ajit; Verma, Sanjay K.; Alvi, P. A.; Jasrotia, Dinesh

    2016-04-01

    The nanospatial morphological features of [ZnCl]- [C5H4NCH3]+ hybrid derivative depicts 28 nm granular size and 3D spreader shape packing pattern as analyzed by FESEM and single crystal XRD structural studies. The organic moiety connect the inorganic components through N-H+…Cl- hydrogen bond to form a hybrid composite, the replacement of organic derivatives from 2-methylpyridine to 2-Amino-5-choloropyridine results the increase in granular size from 28nm to 60nm and unit cell packing pattern from 3D-2D lattice dimensionality along ac plane. The change in optical energy direct band gap value from 3.01eV for [ZnCl]- [C5H4NCH3]+ (HM1) to 3.42eV for [ZnCl]- [C5H5ClN2]+ (HM2) indicates the role of organic moiety in optical properties of hybrid materials. The photoluminescence emission spectra is observed in the wavelength range of 370 to 600 nm with maximum peak intensity of 9.66a.u. at 438 nm for (HM1) and 370 to 600 nm with max peak intensity of 9.91 a.u. at 442 nm for (HM2), indicating that the emission spectra lies in visible range. PL excitation spectra depicts the maximum excitation intensity [9.8] at 245.5 nm for (HM1) and its value of 9.9 a.u. at 294 nm, specify the excitation spectra lies in UV range. Photoluminescence excitation spectra is observed in the wavelength range of 280 to 350 nm with maximum peak intensity of 9.4 a.u. at 285.5 nm and 9.9 a.u. at 294 and 297 nm, indicating excitation in the UV spectrum. Single crystal growth process and detailed physiochemical characterization such as XRD, FESEM image analysis photoluminescence property reveals the structure stability with non-covalent interactions, lattice dimensionality (3D-2D) correlations interweaving into the design of inorganic-organic hybrid materials.

  15. Minimum cost connection networks

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tvede, Mich

    2015-01-01

    In the present paper we consider the allocation of costs in connection networks. Agents have connection demands in form of pairs of locations they want to have connected. Connections between locations are costly to build. The problem is to allocate costs of networks satisfying all connection...... demands. We use a few axioms to characterize allocation rules that truthfully implement cost minimizing networks satisfying all connection demands in a game where: (1) a central planner announces an allocation rule and a cost estimation rule; (2) every agent reports her own connection demand as well...... as all connection costs; (3) the central planner selects a cost minimizing network satisfying reported connection demands based on the estimated costs; and, (4) the planner allocates the true costs of the selected network. It turns out that an allocation rule satisfies the axioms if and only if relative...

  16. Intra- and interobserver reliability and intra-catheter reproducibility using frequency domain optical coherence tomography for the evaluation of morphometric stent parameters and qualitative assessment of stent strut coverage

    International Nuclear Information System (INIS)

    Antonsen, Lisbeth; Thayssen, Per; Junker, Anders; Veien, Karsten Tange; Hansen, Henrik Steen; Hansen, Knud Nørregaard; Hougaard, Mikkel; Jensen, Lisette Okkels

    2015-01-01

    Purpose: Frequency-domain optical coherence tomography (FD-OCT) is a high-resolution imaging tool (~ 10–15 μm), which enables near-histological in-vivo images of the coronary vessel wall. The use of the technique is increasing, both for research- and clinical purposes. This study sought to investigate the intra- and interobserver reliability, as well as the intra-catheter reproducibility of quantitative FD-OCT-assessment of morphometric stent parameters and qualitative FD-OCT-evaluation of strut coverage in 10 randomly selected 6-month follow-up Nobori® biolimus-eluting stents (N-BESs). Methods: Ten N-BESs (213 cross sectional areas (CSAs) and 1897 struts) imaged with OCT 6 months post-implantation were randomly selected and analyzed by 2 experienced analysts, and the same 10 N-BESs were analyzed by one of the analysts 3 months later. Further, 2 consecutive pullbacks randomly performed in another 10 N-BESs (219 CSAs and 1860 struts) were independently assessed by one of the analysts. Results: The intraobserver variability with regard to relative difference of mean luminal area and mean stent area at the CSA-level was very low: 0.1% ± 1.4% and 0.5% ± 3.2%. Interobserver variability also proved to be low: − 2.1% ± 3.3% and 2.1% ± 4.6%, and moreover, very restricted intra-catheter variation was observed: 0.02% ± 6.8% and − 0.18% ± 5.2%. The intraobserver-, interobserver- and intra-catheter reliability for the qualitative evaluation of strut coverage was found to be: kappa (κ) = 0.91 (95% confidence interval (CI): 0.88–0.93, p < 0.01), κ = 0.88 (95% CI: 0.85–0.91, p < 0.01), and κ = 0.73 (95% CI: 0.68–0.78, p < 0.01), respectively. Conclusions: FD-OCT is a reproducible and reliable imaging tool for quantitative evaluation of stented coronary segments, and for qualitative assessment of strut coverage. - Highlights: • Frequency-domain optical coherence tomography (FD-OCT) is increasingly adopted in the catherization laboratories. • This

  17. Intra- and interobserver reliability and intra-catheter reproducibility using frequency domain optical coherence tomography for the evaluation of morphometric stent parameters and qualitative assessment of stent strut coverage

    Energy Technology Data Exchange (ETDEWEB)

    Antonsen, Lisbeth, E-mail: Lisbeth.antonsen@rsyd.dk; Thayssen, Per; Junker, Anders; Veien, Karsten Tange; Hansen, Henrik Steen; Hansen, Knud Nørregaard; Hougaard, Mikkel; Jensen, Lisette Okkels

    2015-12-15

    Purpose: Frequency-domain optical coherence tomography (FD-OCT) is a high-resolution imaging tool (~ 10–15 μm), which enables near-histological in-vivo images of the coronary vessel wall. The use of the technique is increasing, both for research- and clinical purposes. This study sought to investigate the intra- and interobserver reliability, as well as the intra-catheter reproducibility of quantitative FD-OCT-assessment of morphometric stent parameters and qualitative FD-OCT-evaluation of strut coverage in 10 randomly selected 6-month follow-up Nobori® biolimus-eluting stents (N-BESs). Methods: Ten N-BESs (213 cross sectional areas (CSAs) and 1897 struts) imaged with OCT 6 months post-implantation were randomly selected and analyzed by 2 experienced analysts, and the same 10 N-BESs were analyzed by one of the analysts 3 months later. Further, 2 consecutive pullbacks randomly performed in another 10 N-BESs (219 CSAs and 1860 struts) were independently assessed by one of the analysts. Results: The intraobserver variability with regard to relative difference of mean luminal area and mean stent area at the CSA-level was very low: 0.1% ± 1.4% and 0.5% ± 3.2%. Interobserver variability also proved to be low: − 2.1% ± 3.3% and 2.1% ± 4.6%, and moreover, very restricted intra-catheter variation was observed: 0.02% ± 6.8% and − 0.18% ± 5.2%. The intraobserver-, interobserver- and intra-catheter reliability for the qualitative evaluation of strut coverage was found to be: kappa (κ) = 0.91 (95% confidence interval (CI): 0.88–0.93, p < 0.01), κ = 0.88 (95% CI: 0.85–0.91, p < 0.01), and κ = 0.73 (95% CI: 0.68–0.78, p < 0.01), respectively. Conclusions: FD-OCT is a reproducible and reliable imaging tool for quantitative evaluation of stented coronary segments, and for qualitative assessment of strut coverage. - Highlights: • Frequency-domain optical coherence tomography (FD-OCT) is increasingly adopted in the catherization laboratories. • This

  18. Scheme for generating the singlet state of three atoms trapped in distant cavities coupled by optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dong-Yang [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Wen, Jing-Ji [College of Foundation Science, Harbin University of Commerce, Harbin, Heilongjiang 150028 (China); Bai, Cheng-Hua; Hu, Shi; Cui, Wen-Xue [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Wang, Hong-Fu, E-mail: hfwang@ybu.edu.cn [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Zhu, Ai-Dong [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Zhang, Shou, E-mail: szhang@ybu.edu.cn [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China)

    2015-09-15

    An effective scheme is proposed to generate the singlet state with three four-level atoms trapped in three distant cavities connected with each other by three optical fibers, respectively. After a series of appropriate atom–cavity interactions, which can be arbitrarily controlled via the selective pairing of Raman transitions and corresponding optical switches, a three-atom singlet state can be successfully generated. The influence of atomic spontaneous decay, photon leakage of cavities and optical fibers on the fidelity of the state is numerically simulated showing that the three-atom singlet state can be generated with high fidelity by choosing the experimental parameters appropriately.

  19. Physical impairment aware transparent optical networks

    Science.gov (United States)

    Antona, Jean-Christophe; Morea, Annalisa; Zami, Thierry; Leplingard, Florence

    2009-11-01

    As illustrated by optical fiber and optical amplification, optical telecommunications have appeared for the last ten years as one of the most promising candidates to increase the transmission capacities. More recently, the concept of optical transparency has been investigated and introduced: it consists of the optical routing of Wavelength Division Multiplexed (WDM) channels without systematic optoelectronic processing at nodes, as long as propagation impairments remain acceptable [1]. This allows achieving less power-consuming, more scalable and flexible networks, and today partial optical transparency has become a reality in deployed systems. However, because of the evolution of traffic features, optical networks are facing new challenges such as demand for higher transmitted capacity, further upgradeability, and more automation. Making all these evolutions compliant on the same current network infrastructure with a minimum of upgrades is one of the main issues for equipment vendors and operators. Hence, an automatic and efficient management of the network needs a control plan aware of the expected Quality of Transmission (QoT) of the connections to set-up with respect to numerous parameters such as: the services demanded by the customers in terms of protection/restoration; the modulation rate and format of the connection under test and also of its adjacent WDM channels; the engineering rules of the network elements traversed with an accurate knowledge of the associated physical impairments. Whatever the method and/or the technology used to collect this information, the issue about its accuracy is one of the main concerns of the network system vendors, because an inaccurate knowledge could yield a sub-optimal dimensioning and so additional costs when installing the network in the field. Previous studies [1], [2] illustrated the impact of this knowledge accuracy on the ability to predict the connection feasibility. After describing usual methods to build

  20. LOOKING FOR A CONNECTION BETWEEN THE Am PHENOMENON AND HYBRID {delta} Sct -{gamma} Dor PULSATION: DETERMINATION OF THE FUNDAMENTAL PARAMETERS AND ABUNDANCES OF HD 114839 AND BD +18 4914

    Energy Technology Data Exchange (ETDEWEB)

    Hareter, M.; Weiss, W. [Department of Astronomy, University of Vienna, Tuerkenschanzstrasse 17, A-1180 Wien (Austria); Fossati, L. [Department of Physics and Astronomy, Open University, Walton Hall, Milton Keynes MK6 7AA (United Kingdom); Suarez, J. C. [Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia S/N, 18008, Granada (Spain); Uytterhoeven, K. [Kiepenheuer-Institut fuer Sonnenphysik, Schoeneckstr. 6, D-79104 Freiburg (Germany); Rainer, M.; Poretti, E., E-mail: hareter@astro.univie.ac.at [INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807, Merate (Saint Lucia) (Italy)

    2011-12-20

    {delta} Sct-{gamma} Dor hybrids pulsate simultaneously in p- and g-modes, which carry information on the structure of the envelope as well as to the core. Hence, they are key objects for investigating A and F type stars with asteroseismic techniques. An important requirement for seismic modeling is small errors in temperature, gravity, and chemical composition. Furthermore, we want to investigate the existence of an abundance indicator typical for hybrids, something that is well established for the roAp stars. Previous to the present investigation, the abundance pattern of only one hybrid and another hybrid candidate has been published. We obtained high-resolution spectra of HD 114839 and BD +18 4914 using the SOPHIE spectrograph of the Observatoire de Haute-Provence and the HARPS spectrograph at ESO La Silla. For each star we determined fundamental parameters and photospheric abundances of 16 chemical elements by comparing synthetic spectra with the observations. We compare our results to that of seven {delta} Sct and nine {gamma} Dor stars. For the evolved BD +18 4914 we found an abundance pattern typical for an Am star, but could not confirm this peculiarity for the less evolved star HD 114839, which is classified in the literature as uncertain Am star. Our result supports the concept of evolved Am stars being unstable. With our investigation we nearly doubled the number of spectroscopically analyzed {delta} Sct-{gamma} Dor hybrid stars, but did not yet succeed in identifying a spectroscopic signature for this group of pulsating stars. A statistically significant spectroscopic investigation of {delta} Sct- {gamma} Dor hybrid stars is still missing, but would be rewarding considering the asteroseismological potential of this group.

  1. LOOKING FOR A CONNECTION BETWEEN THE Am PHENOMENON AND HYBRID δ Sct -γ Dor PULSATION: DETERMINATION OF THE FUNDAMENTAL PARAMETERS AND ABUNDANCES OF HD 114839 AND BD +18 4914

    International Nuclear Information System (INIS)

    Hareter, M.; Weiss, W.; Fossati, L.; Suárez, J. C.; Uytterhoeven, K.; Rainer, M.; Poretti, E.

    2011-01-01

    δ Sct-γ Dor hybrids pulsate simultaneously in p- and g-modes, which carry information on the structure of the envelope as well as to the core. Hence, they are key objects for investigating A and F type stars with asteroseismic techniques. An important requirement for seismic modeling is small errors in temperature, gravity, and chemical composition. Furthermore, we want to investigate the existence of an abundance indicator typical for hybrids, something that is well established for the roAp stars. Previous to the present investigation, the abundance pattern of only one hybrid and another hybrid candidate has been published. We obtained high-resolution spectra of HD 114839 and BD +18 4914 using the SOPHIE spectrograph of the Observatoire de Haute-Provence and the HARPS spectrograph at ESO La Silla. For each star we determined fundamental parameters and photospheric abundances of 16 chemical elements by comparing synthetic spectra with the observations. We compare our results to that of seven δ Sct and nine γ Dor stars. For the evolved BD +18 4914 we found an abundance pattern typical for an Am star, but could not confirm this peculiarity for the less evolved star HD 114839, which is classified in the literature as uncertain Am star. Our result supports the concept of evolved Am stars being unstable. With our investigation we nearly doubled the number of spectroscopically analyzed δ Sct-γ Dor hybrid stars, but did not yet succeed in identifying a spectroscopic signature for this group of pulsating stars. A statistically significant spectroscopic investigation of δ Sct- γ Dor hybrid stars is still missing, but would be rewarding considering the asteroseismological potential of this group.

  2. Inventory parameters

    CERN Document Server

    Sharma, Sanjay

    2017-01-01

    This book provides a detailed overview of various parameters/factors involved in inventory analysis. It especially focuses on the assessment and modeling of basic inventory parameters, namely demand, procurement cost, cycle time, ordering cost, inventory carrying cost, inventory stock, stock out level, and stock out cost. In the context of economic lot size, it provides equations related to the optimum values. It also discusses why the optimum lot size and optimum total relevant cost are considered to be key decision variables, and uses numerous examples to explain each of these inventory parameters separately. Lastly, it provides detailed information on parameter estimation for different sectors/products. Written in a simple and lucid style, it offers a valuable resource for a broad readership, especially Master of Business Administration (MBA) students.

  3. Power inverter with optical isolation

    Science.gov (United States)

    Duncan, Paul G.; Schroeder, John Alan

    2005-12-06

    An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

  4. Electro-optics laboratory evaluation: Deutsch optical waveguide connectors

    Science.gov (United States)

    1980-01-01

    A description of a test program evaluating the performance of an optical waveguide connector system is presented. Both quality and effectiveness of connections made in an optical fiber, performance of the equipment used and applicability of equipment and components to field conditions are reviewed.

  5. Connected vehicle standards.

    Science.gov (United States)

    2016-01-01

    Connected vehicles have the potential to transform the way Americans travel by : allowing cars, buses, trucks, trains, traffic signals, smart phones, and other devices to : communicate through a safe, interoperable wireless network. A connected vehic...

  6. Connecting to Everyday Practices

    DEFF Research Database (Denmark)

    Iversen, Ole Sejer; Smith, Rachel Charlotte

    2012-01-01

    construction and reproduction of cultural heritage creating novel connections between self and others and between past, present and future. We present experiences from a current research project, the Digital Natives exhibition, in which social media was designed as an integral part of the exhibition to connect...... focusing on the connections between audiences practices and the museum exhibition....

  7. Elements of quantum optics

    CERN Document Server

    Meystre, Pierre

    2007-01-01

    Elements of Quantum Optics gives a self-contained and broad coverage of the basic elements necessary to understand and carry out research in laser physics and quantum optics, including a review of basic quantum mechanics and pedagogical introductions to system-reservoir interactions and to second quantization. The text reveals the close connection between many seemingly unrelated topics, such as probe absorption, four-wave mixing, optical instabilities, resonance fluorescence and squeezing. It also comprises discussions of cavity quantum electrodynamics and atom optics. The 4th edition includes a new chapter on quantum entanglement and quantum information, as well as added discussions of the quantum beam splitter, electromagnetically induced transparency, slow light, and the input-output formalism needed to understand many problems in quantum optics. It also provides an expanded treatment of the minimum-coupling Hamiltonian and a simple derivation of the Gross-Pitaevskii equation, an important gateway to rese...

  8. Optical network democratization.

    Science.gov (United States)

    Nejabati, Reza; Peng, Shuping; Simeonidou, Dimitra

    2016-03-06

    The current Internet infrastructure is not able to support independent evolution and innovation at physical and network layer functionalities, protocols and services, while at same time supporting the increasing bandwidth demands of evolving and heterogeneous applications. This paper addresses this problem by proposing a completely democratized optical network infrastructure. It introduces the novel concepts of the optical white box and bare metal optical switch as key technology enablers for democratizing optical networks. These are programmable optical switches whose hardware is loosely connected internally and is completely separated from their control software. To alleviate their complexity, a multi-dimensional abstraction mechanism using software-defined network technology is proposed. It creates a universal model of the proposed switches without exposing their technological details. It also enables a conventional network programmer to develop network applications for control of the optical network without specific technical knowledge of the physical layer. Furthermore, a novel optical network virtualization mechanism is proposed, enabling the composition and operation of multiple coexisting and application-specific virtual optical networks sharing the same physical infrastructure. Finally, the optical white box and the abstraction mechanism are experimentally evaluated, while the virtualization mechanism is evaluated with simulation. © 2016 The Author(s).

  9. Network connectivity value.

    Science.gov (United States)

    Dragicevic, Arnaud; Boulanger, Vincent; Bruciamacchie, Max; Chauchard, Sandrine; Dupouey, Jean-Luc; Stenger, Anne

    2017-04-21

    In order to unveil the value of network connectivity, we formalize the construction of ecological networks in forest environments as an optimal control dynamic graph-theoretic problem. The network is based on a set of bioreserves and patches linked by ecological corridors. The node dynamics, built upon the consensus protocol, form a time evolutive Mahalanobis distance weighted by the opportunity costs of timber production. We consider a case of complete graph, where the ecological network is fully connected, and a case of incomplete graph, where the ecological network is partially connected. The results show that the network equilibrium depends on the size of the reception zone, while the network connectivity depends on the environmental compatibility between the ecological areas. Through shadow prices, we find that securing connectivity in partially connected networks is more expensive than in fully connected networks, but should be undertaken when the opportunity costs are significant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Analysis of Energy Efficiency in Dynamic Optical Networks Employing Solar Energy Sources

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2013-01-01

    The paper presents energy efficient routing in dynamic optical networks, where solar energy sources are employed for the network nodes. Different parameters are evaluated, including the number of nodes that have access to solar energy sources, the different maximum solar output power, traffic type...... and the locations of solar powered nodes. Results show a maximum 39% savings in energy consumption with different increases in connection blocking probability....

  11. Gradient-index optics fundamentals and applications

    CERN Document Server

    Gomez-Reino, Carlos; Bao, Carmen

    2010-01-01

    Gradient-Index (GRIN) optics provides a comprehensive and thorough treatment on fundamentals and applications of light propagation through inhomogeneous media. The book can be used both as a classroom text for students in physics and engineering and as a reference for specialists. A description of the phenomena, components and technology used in GRIN Optics are presented. The relationship to lenses, waveguides, optical connections, spatial solitons and vision is demonstrated. Applications of GRIN components and hybrid structures for optical connections, optical sensing and Talbot effect are analyzed.

  12. Optical Interconnection Via Computer-Generated Holograms

    Science.gov (United States)

    Liu, Hua-Kuang; Zhou, Shaomin

    1995-01-01

    Method of free-space optical interconnection developed for data-processing applications like parallel optical computing, neural-network computing, and switching in optical communication networks. In method, multiple optical connections between multiple sources of light in one array and multiple photodetectors in another array made via computer-generated holograms in electrically addressed spatial light modulators (ESLMs). Offers potential advantages of massive parallelism, high space-bandwidth product, high time-bandwidth product, low power consumption, low cross talk, and low time skew. Also offers advantage of programmability with flexibility of reconfiguration, including variation of strengths of optical connections in real time.

  13. Application of STEM/EELS to Plasmon-Related Effects in Optical Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Camden, Jon [Univ. of Notre Dame, IN (United States). Dept. of Chemistry and Biochemistry

    2017-08-15

    In this project we employed EELS/STEM to understand the near-field enhancements that drive current applications of plasmonic nanostructures. In particular, we explore the connection between optical and electron excitation of plasmon modes in metallic nanostructures: (1) Probing the structural parameters and dielectric properties of multimetallic nanoparticles; (2) Characterization of the near-electric-field enhancements obtained upon excitation of the localized surface plasmon resonance and understand the connection between electron- and photon-driven plasmons; (3) Understanding the behavior of molecules in plasmon-enhanced fields which is essential to emerging applications such as plasmon-assisted catalysis and solar energy harvesting.

  14. Neutron strength functions: the link between resolved resonances and the optical model

    International Nuclear Information System (INIS)

    Moldauer, P.A.

    1980-01-01

    Neutron strength functions and scattering radii are useful as energy and channel radius independent parameters that characterize neutron scattering resonances and provide a connection between R-matrix resonance analysis and the optical model. The choice of R-matrix channel radii is discussed, as are limitations on the accuracies of strength functions. New definitions of the p-wave strength function and scattering radius are proposed. For light nuclei, where strength functions display optical model energy variations over the resolved resonances, a doubly reduced partial neutron width is introduced for more meaningful statistical analyses of widths. The systematic behavior of strength functions and scattering radii is discussed

  15. Study on the Connecting Length of CFRP

    Science.gov (United States)

    Liu, Xiongfei; Li, Yue; Li, Zhanguo

    2018-05-01

    The paper studied the varying mode of shear stress in the connecting zone of CFRP. Using epoxy resin (EP) as bond material, performance of specimens with different connecting length of CFRP was tested to obtain the conclusion. CFRP-confined concrete column was tested subsequently to verify the conclusion. The results show that: (1) The binding properties of modified epoxy resin with CFRP is good; (2) As the connecting length increased, the ultimate tensile strength of CFRP increased as well in the range of the experiment parameters; (3) Tensile strength of CFRP can reach the ultimate strength when the connecting length is 90mm;(4) The connecting length of 90mm of CFRP meet the reinforcement requirements.

  16. Optical terminal requirements for aeronautical multi-hop networks

    Science.gov (United States)

    Karras, Kimon; Marinos, Dimitris; Kouros, Pavlos

    2008-08-01

    High speed free space optical data links are currently finding limited use in military aircraft; however the technology is slowly starting to diffuse to civilian applications, where they could be used to provide a high bandwidth connection. However there are several issues that have to be resolved before the technology is ready for deployment. An important part of these are physical layer issues which deal with the ability to transmit and receive the optical signal reliably, as well as mechanical issues which focus on the construction of high performance, small and lightweight terminals for the optical transceiver. The later in conjunction with the cost of such a terminal create a significant limitation on the number of such equipment that any aircraft might carry on board. This paper attempts to evaluate how various such parameters affect the capability of an aircraft to take part in and help form a mesh network. The study was conducted by modeling the aircraft into a custom built SystemC based simulator tool and evaluating the connectivity achieved for varying several parameters, such as the pointing and acquisition time of the terminal and the number of terminals on board.

  17. Bomb parameters

    International Nuclear Information System (INIS)

    Kerr, George D.; Young, Rebert W.; Cullings, Harry M.; Christry, Robert F.

    2005-01-01

    The reconstruction of neutron and gamma-ray doses at Hiroshima and Nagasaki begins with a determination of the parameters describing the explosion. The calculations of the air transported radiation fields and survivor doses from the Hiroshima and Nagasaki bombs require knowledge of a variety of parameters related to the explosions. These various parameters include the heading of the bomber when the bomb was released, the epicenters of the explosions, the bomb yields, and the tilt of the bombs at time of explosion. The epicenter of a bomb is the explosion point in air that is specified in terms of a burst height and a hypocenter (or the point on the ground directly below the epicenter of the explosion). The current reassessment refines the energy yield and burst height for the Hiroshima bomb, as well as the locations of the Hiroshima and Nagasaki hypocenters on the modern city maps used in the analysis of the activation data for neutrons and TLD data for gamma rays. (J.P.N.)

  18. Optical Performance Monitoring and Signal Optimization in Optical Networks

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal

    2006-01-01

    The thesis studies performance monitoring for the next generation optical networks. The focus is on all-optical networks with bit-rates of 10 Gb/s or above. Next generation all-optical networks offer large challenges as the optical transmitted distance increases and the occurrence of electrical-optical......-electrical regeneration points decreases. This thesis evaluates the impact of signal degrading effects that are becoming of increasing concern in all-optical high-speed networks due to all-optical switching and higher bit-rates. Especially group-velocity-dispersion (GVD) and a number of nonlinear effects will require...... enhanced attention to avoid signal degradations. The requirements for optical performance monitoring features are discussed, and the thesis evaluates the advantages and necessity of increasing the level of performance monitoring parameters in the physical layer. In particular, methods for optical...

  19. Handbook of networking & connectivity

    CERN Document Server

    McClain, Gary R

    1994-01-01

    Handbook of Networking & Connectivity focuses on connectivity standards in use, including hardware and software options. The book serves as a guide for solving specific problems that arise in designing and maintaining organizational networks.The selection first tackles open systems interconnection, guide to digital communications, and implementing TCP/IP in an SNA environment. Discussions focus on elimination of the SNA backbone, routing SNA over internets, connectionless versus connection-oriented networks, internet concepts, application program interfaces, basic principles of layering, proto

  20. Feasibility of using fiber optics for monitoring ground water contaminants

    International Nuclear Information System (INIS)

    Hirschfeld, T.; Deaton, T.; Milanovich, F.; Klainer, S.M.

    1984-06-01

    The report contains the results of the initial feasibility study for a research program undertaken to develop the technology needed to use fiber optics for monitoring groundwater contaminants. The technology appears especially well suited to the requirements of detection monitoring where a few indicator parameters can be measured continuously by sensors placed down small-diameter monitoring wells. Data are generated at a remote, centrally located fluorimeter, connected to the sampling sites by inexpensive optical fibers. The analytical method is laser-induced fluorescence which gives the desired sensitivity. The optrode, a chemical system and/or a mechanical device at the distal end of a fiber optic, furnishes the needed specificity. Various fiber and optrode configurations have been evaluated and their applications to groundwater monitoring are discussed. Feasibility is shown for physical measurements such as temperature, pressure and pH. Chemical detection and quantification of the actinides, inorganic and organic chlorides, sulfates, alcohols, aldehydes, pesticides and tracer materials are presented. Finally, it is shown that the need for smaller diameter wells (as compared to conventional sampling methods), and the ability to make up to 50 unattended in situ measurements, using a reasonably priced centralized fluorometer system connected to the sampling sites by inexpensive optical fibers, results in acceptable economy

  1. 78 FR 55684 - ConnectED Workshop

    Science.gov (United States)

    2013-09-11

    ... tools move everything from homework assignments to testing into the cloud. The workshop will explore possible strategies to connect virtually all of our students to next-generation broadband in a timely, cost-effective way. It will also share promising practices, from NTIA's Broadband Technology Opportunities...

  2. The Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    Young, Stanley

    2017-04-24

    The Connected Traveler project is a multi-disciplinary undertaking that seeks to validate potential for transformative transportation system energy savings by incentivizing energy efficient travel behavior.

  3. Connections: All Issues

    Science.gov (United States)

    Goals Recycling Green Purchasing Pollution Prevention Reusing Water Resources Environmental Management Plateau, and more... Connections Newsletter December 2016 December 2016 Science-themed gifts available at

  4. Critical parameters for ammonia

    International Nuclear Information System (INIS)

    Sato, M.; Masui, G.; Uematsu, M.

    2005-01-01

    (p, ρ, T) measurements and visual observations of the meniscus for ammonia were carried out carefully in the critical region over the range of temperatures: -1 K (T - T c ) 0.04 K, and of densities: -19 kg . m -3 (ρ - ρ c ) 19 kg . m -3 by a metal-bellows volumometer with an optical cell. Vapor pressures were also measured at T = (310, 350, and 400) K. The critical parameters of T c and ρ c were determined based on the results of observation of the critical opalescence. The critical pressure p c was determined from the present measurements at T c on the vapor pressure curve. Comparisons of the critical parameters with values given in the literature are presented

  5. Critical parameters for ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M. [Center for Mechanical Engineering and Applied Mechanics, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan); Masui, G. [Center for Mechanical Engineering and Applied Mechanics, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan); Uematsu, M. [Center for Mechanical Engineering and Applied Mechanics, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan)]. E-mail: uematsu@mech.keio.ac.jp

    2005-09-15

    (p, {rho}, T) measurements and visual observations of the meniscus for ammonia were carried out carefully in the critical region over the range of temperatures: -1 K (T - T {sub c}) 0.04 K, and of densities: -19 kg . m{sup -3} ({rho} - {rho} {sub c}) 19 kg . m{sup -3} by a metal-bellows volumometer with an optical cell. Vapor pressures were also measured at T = (310, 350, and 400) K. The critical parameters of T {sub c} and {rho} {sub c} were determined based on the results of observation of the critical opalescence. The critical pressure p {sub c} was determined from the present measurements at T {sub c} on the vapor pressure curve. Comparisons of the critical parameters with values given in the literature are presented.

  6. Radiation parameters of the X-ray binary A 0535+26=HDE 245770 from the polarization and photometric data

    International Nuclear Information System (INIS)

    Larionov, V.M.

    1987-01-01

    An analysis of Shakhovskay et al's observations of the X-ray binary A 0535+26=HDE 245770 made it possible to distinguish in its radiation the two components connected with the visible star (O9 III) and the accretion disc around the neutron star. The interstellar polarization parameters are in accordance with Serkowski's formula and the observations of the field stars. The IR and optical variability can be explained in terms of variable accretion disc radiation. The intrinsic polarization parameters obtained can be used to predict, in the model proposed, the directions of the polarization vectors in the IR and X-ray bands

  7. Experimental demonstration of a cognitive quality of transmission estimator for optical communication systems

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Aguado, Juan Carlos; Borkowski, Robert

    2012-01-01

    small and not optimized underlying knowledge base, it achieves between 79% and 98.7% successful classifications based on the error vector magnitude (EVM) parameter, and approximately 100% when the classification is based on the optical signal to noise ratio (OSNR).......The impact of physical layer impairments in optical network design and operation has received significant attention in the last years, thereby requiring estimation techniques to predict the quality of transmission (QoT) of optical connections before being established. In this paper, we report...... on the experimental demonstration of a case-based reasoning (CBR) technique to predict whether optical channels fulfill QoT requirements, thus supporting impairment-aware networking. The validation of the cognitive QoT estimator is performed in a WDM 80 Gb/s PDM-QPSK testbed, and we demonstrate that even with a very...

  8. Archives: Mathematics Connection

    African Journals Online (AJOL)

    Items 1 - 9 of 9 ... Archives: Mathematics Connection. Journal Home > Archives: Mathematics Connection. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. 1 - 9 of 9 Items. 2011 ...

  9. Connective Tissue Disorders

    Science.gov (United States)

    ... of connective tissue. Over 200 disorders that impact connective tissue. There are different types: Genetic disorders, such as Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta Autoimmune disorders, such as lupus and scleroderma Cancers, like some types of soft tissue sarcoma Each ...

  10. Geometric phases in astigmatic optical modes of arbitrary order

    International Nuclear Information System (INIS)

    Habraken, Steven J. M.; Nienhuis, Gerard

    2010-01-01

    The transverse spatial structure of a paraxial beam of light is fully characterized by a set of parameters that vary only slowly under free propagation. They specify bosonic ladder operators that connect modes of different orders, in analogy to the ladder operators connecting harmonic-oscillator wave functions. The parameter spaces underlying sets of higher-order modes are isomorphic to the parameter space of the ladder operators. We study the geometry of this space and the geometric phase that arises from it. This phase constitutes the ultimate generalization of the Gouy phase in paraxial wave optics. It reduces to the ordinary Gouy phase and the geometric phase of nonastigmatic optical modes with orbital angular momentum in limiting cases. We briefly discuss the well-known analogy between geometric phases and the Aharonov-Bohm effect, which provides some complementary insights into the geometric nature and origin of the generalized Gouy phase shift. Our method also applies to the quantum-mechanical description of wave packets. It allows for obtaining complete sets of normalized solutions of the Schroedinger equation. Cyclic transformations of such wave packets give rise to a phase shift, which has a geometric interpretation in terms of the other degrees of freedom involved.

  11. Generalized connectivity of graphs

    CERN Document Server

    Li, Xueliang

    2016-01-01

    Noteworthy results, proof techniques, open problems and conjectures in generalized (edge-) connectivity are discussed in this book. Both theoretical and practical analyses for generalized (edge-) connectivity of graphs are provided. Topics covered in this book include: generalized (edge-) connectivity of graph classes, algorithms, computational complexity, sharp bounds, Nordhaus-Gaddum-type results, maximum generalized local connectivity, extremal problems, random graphs, multigraphs, relations with the Steiner tree packing problem and generalizations of connectivity. This book enables graduate students to understand and master a segment of graph theory and combinatorial optimization. Researchers in graph theory, combinatorics, combinatorial optimization, probability, computer science, discrete algorithms, complexity analysis, network design, and the information transferring models will find this book useful in their studies.

  12. Handbook of Brain Connectivity

    CERN Document Server

    Jirsa, Viktor K

    2007-01-01

    Our contemporary understanding of brain function is deeply rooted in the ideas of the nonlinear dynamics of distributed networks. Cognition and motor coordination seem to arise from the interactions of local neuronal networks, which themselves are connected in large scales across the entire brain. The spatial architectures between various scales inevitably influence the dynamics of the brain and thereby its function. But how can we integrate brain connectivity amongst these structural and functional domains? Our Handbook provides an account of the current knowledge on the measurement, analysis and theory of the anatomical and functional connectivity of the brain. All contributors are leading experts in various fields concerning structural and functional brain connectivity. In the first part of the Handbook, the chapters focus on an introduction and discussion of the principles underlying connected neural systems. The second part introduces the currently available non-invasive technologies for measuring struct...

  13. Modeling Structural Brain Connectivity

    DEFF Research Database (Denmark)

    Ambrosen, Karen Marie Sandø

    The human brain consists of a gigantic complex network of interconnected neurons. Together all these connections determine who we are, how we react and how we interpret the world. Knowledge about how the brain is connected can further our understanding of the brain’s structural organization, help...... improve diagnosis, and potentially allow better treatment of a wide range of neurological disorders. Tractography based on diffusion magnetic resonance imaging is a unique tool to estimate this “structural connectivity” of the brain non-invasively and in vivo. During the last decade, brain connectivity...... has increasingly been analyzed using graph theoretic measures adopted from network science and this characterization of the brain’s structural connectivity has been shown to be useful for the classification of populations, such as healthy and diseased subjects. The structural connectivity of the brain...

  14. Nonlinear optics

    International Nuclear Information System (INIS)

    Boyd, R.W.

    1992-01-01

    Nonlinear optics is the study of the interaction of intense laser light with matter. This book is a textbook on nonlinear optics at the level of a beginning graduate student. The intent of the book is to provide an introduction to the field of nonlinear optics that stresses fundamental concepts and that enables the student to go on to perform independent research in this field. This book covers the areas of nonlinear optics, quantum optics, quantum electronics, laser physics, electrooptics, and modern optics

  15. Physical optics

    International Nuclear Information System (INIS)

    Kim Il Gon; Lee, Seong Su; Jang, Gi Wan

    2012-07-01

    This book indicates physical optics with properties and transmission of light, mathematical expression of wave like harmonic wave and cylindrical wave, electromagnetic theory and light, transmission of light with Fermat principle and Fresnel equation, geometrical optics I, geometrical optics II, optical instrument such as stops, glasses and camera, polarized light like double refraction by polarized light, interference, interference by multiple reflections, diffraction, solid optics, crystal optics such as Faraday rotation and Kerr effect and measurement of light. Each chapter has an exercise.

  16. Physical optics

    Energy Technology Data Exchange (ETDEWEB)

    Kim Il Gon; Lee, Seong Su; Jang, Gi Wan

    2012-07-15

    This book indicates physical optics with properties and transmission of light, mathematical expression of wave like harmonic wave and cylindrical wave, electromagnetic theory and light, transmission of light with Fermat principle and Fresnel equation, geometrical optics I, geometrical optics II, optical instrument such as stops, glasses and camera, polarized light like double refraction by polarized light, interference, interference by multiple reflections, diffraction, solid optics, crystal optics such as Faraday rotation and Kerr effect and measurement of light. Each chapter has an exercise.

  17. Quantum optics

    National Research Council Canada - National Science Library

    Agarwal, G. S

    2013-01-01

    .... Focusing on applications of quantum optics, the textbook covers recent developments such as engineering of quantum states, quantum optics on a chip, nano-mechanical mirrors, quantum entanglement...

  18. Optical waveguide demultiplexer

    International Nuclear Information System (INIS)

    Gajdaj, Yu.O.; Maslyukyivs'kij, R.M.; Sirota, A.V.

    2009-01-01

    For channels division in fibre-optical networks with wavelength multiplexing, the planar waveguide together with a prism coupler is offered for using. The planar waveguide fulfils a role of a dispersing unit, and prism coupler is the selector of optical channels. The parameters of the planar waveguide which provide maximal space division of adjacent information channels in networks with coarse wavelength multiplexing are calculated

  19. Physiological parameters

    International Nuclear Information System (INIS)

    Natera, E.S.

    1998-01-01

    The physiological characteristics of man depend on the intake, metabolism and excretion of stable elements from food, water, and air. The physiological behavior of natural radionuclides and radionuclides from nuclear weapons testing and from the utilization of nuclear energy is believed to follow the pattern of stable elements. Hence information on the normal physiological processes occurring in the human body plays an important role in the assessment of the radiation dose received by man. Two important physiological parameters needed for internal dose determination are the pulmonary function and the water balance. In the Coordinated Research Programme on the characterization of Asian population, five participants submitted data on these physiological characteristics - China, India, Japan, Philippines and Viet Nam. During the CRP, data on other pertinent characteristics such as physical and dietary were simultaneously being collected. Hence, the information on the physiological characteristics alone, coming from the five participants were not complete and are probably not sufficient to establish standard values for the Reference Asian Man. Nonetheless, the data collected is a valuable contribution to this research programme

  20. Optical measuring system with an interrogator and a polymer-based single-mode fibre optic sensor system

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to an optical measuring system comprising a polymer-based single-mode fibre-optic sensor system (102), an optical interrogator (101), and an optical arrangement (103) interconnecting the optical interrogator (101) and the polymer-based single-mode fibre-optic sensor...... system (102). The invention further relates to an optical interrogator adapted to be connected to a polymer-based single-mode fibre-optic sensor system via an optical arrangement. The interrogator comprises a broadband light source arrangement (104) and a spectrum analysing arrangement which receives...

  1. Ecological connectivity networks in rapidly expanding cities.

    Science.gov (United States)

    Nor, Amal Najihah M; Corstanje, Ron; Harris, Jim A; Grafius, Darren R; Siriwardena, Gavin M

    2017-06-01

    Urban expansion increases fragmentation of the landscape. In effect, fragmentation decreases connectivity, causes green space loss and impacts upon the ecology and function of green space. Restoration of the functionality of green space often requires restoring the ecological connectivity of this green space within the city matrix. However, identifying ecological corridors that integrate different structural and functional connectivity of green space remains vague. Assessing connectivity for developing an ecological network by using efficient models is essential to improve these networks under rapid urban expansion. This paper presents a novel methodological approach to assess and model connectivity for the Eurasian tree sparrow ( Passer montanus ) and Yellow-vented bulbul ( Pycnonotus goiavier ) in three cities (Kuala Lumpur, Malaysia; Jakarta, Indonesia and Metro Manila, Philippines). The approach identifies potential priority corridors for ecological connectivity networks. The study combined circuit models, connectivity analysis and least-cost models to identify potential corridors by integrating structure and function of green space patches to provide reliable ecological connectivity network models in the cities. Relevant parameters such as landscape resistance and green space structure (vegetation density, patch size and patch distance) were derived from an expert and literature-based approach based on the preference of bird behaviour. The integrated models allowed the assessment of connectivity for both species using different measures of green space structure revealing the potential corridors and least-cost pathways for both bird species at the patch sites. The implementation of improvements to the identified corridors could increase the connectivity of green space. This study provides examples of how combining models can contribute to the improvement of ecological networks in rapidly expanding cities and demonstrates the usefulness of such models for

  2. Ecological connectivity networks in rapidly expanding cities

    Directory of Open Access Journals (Sweden)

    Amal Najihah M. Nor

    2017-06-01

    Full Text Available Urban expansion increases fragmentation of the landscape. In effect, fragmentation decreases connectivity, causes green space loss and impacts upon the ecology and function of green space. Restoration of the functionality of green space often requires restoring the ecological connectivity of this green space within the city matrix. However, identifying ecological corridors that integrate different structural and functional connectivity of green space remains vague. Assessing connectivity for developing an ecological network by using efficient models is essential to improve these networks under rapid urban expansion. This paper presents a novel methodological approach to assess and model connectivity for the Eurasian tree sparrow (Passer montanus and Yellow-vented bulbul (Pycnonotus goiavier in three cities (Kuala Lumpur, Malaysia; Jakarta, Indonesia and Metro Manila, Philippines. The approach identifies potential priority corridors for ecological connectivity networks. The study combined circuit models, connectivity analysis and least-cost models to identify potential corridors by integrating structure and function of green space patches to provide reliable ecological connectivity network models in the cities. Relevant parameters such as landscape resistance and green space structure (vegetation density, patch size and patch distance were derived from an expert and literature-based approach based on the preference of bird behaviour. The integrated models allowed the assessment of connectivity for both species using different measures of green space structure revealing the potential corridors and least-cost pathways for both bird species at the patch sites. The implementation of improvements to the identified corridors could increase the connectivity of green space. This study provides examples of how combining models can contribute to the improvement of ecological networks in rapidly expanding cities and demonstrates the usefulness of such

  3. Management Science, Economics and Finance: A Connection

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); M.J. McAleer (Michael); W.-K. Wong (Wing-Keung)

    2016-01-01

    textabstractThis paper provides a brief review of the connecting literature in management science, economics and finance, and discusses some research that is related to the three disciplines. Academics could develop theoretical models and subsequent econometric models to estimate the parameters in

  4. Connected motorcycle system performance.

    Science.gov (United States)

    2016-01-15

    This project characterized the performance of Connected Vehicle Systems (CVS) on motorcycles based on two key components: global positioning and wireless communication systems. Considering that Global Positioning System (GPS) and 5.9 GHz Dedicated Sh...

  5. Connected vehicle applications : environment.

    Science.gov (United States)

    2016-01-01

    The U.S. Department of Transportation has developed a number of connected vehicle environmental applications, including the Applications for the Environment Real-Time Information Synthesis (AERIS) research program applications and road weather applic...

  6. Connected vehicle applications : safety.

    Science.gov (United States)

    2016-01-01

    Connected vehicle safety applications are designed to increase situational awareness : and reduce or eliminate crashes through vehicle-to-infrastructure, vehicle-to-vehicle, : and vehicle-to-pedestrian data transmissions. Applications support advisor...

  7. IDRC Connect User Guide

    International Development Research Centre (IDRC) Digital Library (Canada)

    Kristina Kamichaitis

    Once an account has been created by IDRC staff, you will receive .... content label in the table to access additional information. Table 3: ... One of the primary functions of IDRC Connect is to enable efficient and automated submission of final.

  8. Connected vehicles and cybersecurity.

    Science.gov (United States)

    2016-01-01

    Connected vehicles are a next-generation technology in vehicles and in infrastructure that will make travel safer, cleaner, and more efficient. The advanced wireless technology enables vehicles to share and communicate information with each other and...

  9. Hydrologically Connected Road Segments

    Data.gov (United States)

    Vermont Center for Geographic Information — Link it ArcGIS Item is HERE.The connectivity layer was created to assist municipalities in preparing for the forthcoming DEC Municipal Roads General Permit in 2018....

  10. IDRC Connect User Guide

    International Development Research Centre (IDRC) Digital Library (Canada)

    Kristina Kamichaitis

    IDRC Extranet home page, which is an umbrella for a number of applications available to IDRC external users. ... IDRC Connect is not formatted for mobile users. ..... Thesis. • Training Material. • Website. • Working Paper. • Workshop Report.

  11. Design issues for semi-passive optical communication devices

    Science.gov (United States)

    Glaser, I.

    2007-09-01

    Optical smart cards are devices containing a retro-reflector, light modulator, and some computing and data storage capabilities to affect semi-passive communication. They do not produce light; instead they modulate and send back light received from a stationary unit. These devices can replace contact-based smart cards as well as RF based ones for applications ranging from identification to transmitting and validating data. Since their transmission is essentially focused on the receiving unit, they are harder to eavesdrop than RF devices, yet need no physical contact or alignment. In this paper we explore optical design issues of these devices and estimate their optical behavior. Specifically, we analyze how these compact devices can be optimized for selected application profiles. Some of the key parameters addressed are effective light efficiency (how much modulated signal can be received by the stationary unit given the amount of light it transmits), range of tilt angles (angle between device surface normal to the line connecting the optical smart card with the stationary unit) through which the device would be effective, and power requirements of the semi-passive unit. In addition, issues concerning compact packaging of this device are discussed. Finally, results of the analysis are employed to produce a comparison of achievable capabilities of these optical smart cards, as opposed to alternative devices, and discuss potential applications were they can be best utilized.

  12. [Connective tissue and inflammation].

    Science.gov (United States)

    Jakab, Lajos

    2014-03-23

    The author summarizes the structure of the connective tissues, the increasing motion of the constituents, which determine the role in establishing the structure and function of that. The structure and function of the connective tissue are related to each other in the resting as well as inflammatory states. It is emphasized that cellular events in the connective tissue are part of the defence of the organism, the localisation of the damage and, if possible, the maintenance of restitutio ad integrum. The organism responds to damage with inflammation, the non specific immune response, as well as specific, adaptive immunity. These processes are located in the connective tissue. Sterile and pathogenic inflammation are relatively similar processes, but inevitable differences are present, too. Sialic acids and glycoproteins containing sialic acids have important roles, and the role of Siglecs is also highlighted. Also, similarities and differences in damages caused by pathogens and sterile agents are briefly summarized. In addition, the roles of adhesion molecules linked to each other, and the whole event of inflammatory processes are presented. When considering practical consequences it is stressed that the structure (building up) of the organism and the defending function of inflammation both have fundamental importance. Inflammation has a crucial role in maintaining the integrity and the unimpaired somato-psychological state of the organism. Thus, inflammation serves as a tool of organism identical with the natural immune response, inseparably connected with the specific, adaptive immune response. The main events of the inflammatory processes take place in the connective tissue.

  13. Quick connect fastener

    Science.gov (United States)

    Weddendorf, Bruce

    1994-01-01

    A quick connect fastener and method of use is presented wherein the quick connect fastener is suitable for replacing available bolts and screws, the quick connect fastener being capable of installation by simply pushing a threaded portion of the connector into a member receptacle hole, the inventive apparatus being comprised of an externally threaded fastener having a threaded portion slidably mounted upon a stud or bolt shaft, wherein the externally threaded fastener portion is expandable by a preloaded spring member. The fastener, upon contact with the member receptacle hole, has the capacity of presenting cylindrical threads of a reduced diameter for insertion purposes and once inserted into the receiving threads of the receptacle member hole, are expandable for engagement of the receptacle hole threads forming a quick connect of the fastener and the member to be fastened, the quick connect fastener can be further secured by rotation after insertion, even to the point of locking engagement, the quick connect fastener being disengagable only by reverse rotation of the mated thread engagement.

  14. Connectivity in river deltas

    Science.gov (United States)

    Passalacqua, P.; Hiatt, M. R.; Sendrowski, A.

    2016-12-01

    Deltas host approximately half a billion people and are rich in ecosystem diversity and economic resources. However, human-induced activities and climatic shifts are significantly impacting deltas around the world; anthropogenic disturbance, natural subsidence, and eustatic sea-level rise are major causes of threat to deltas and in many cases have compromised their safety and sustainability, putting at risk the people that live on them. In this presentation, I will introduce a framework called Delta Connectome for studying connectivity in river deltas based on different representations of a delta as a network. Here connectivity indicates both physical connectivity (how different portions of the system interact with each other) as well as conceptual (pathways of process coupling). I will explore several network representations and show how quantifying connectivity can advance our understanding of system functioning and can be used to inform coastal management and restoration. From connectivity considerations, the delta emerges as a leaky network that evolves over time and is characterized by continuous exchanges of fluxes of matter, energy, and information. I will discuss the implications of connectivity on delta functioning, land growth, and potential for nutrient removal.

  15. EDITORIAL: Optical orientation Optical orientation

    Science.gov (United States)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  16. Generalized fiber Fourier optics.

    Science.gov (United States)

    Cincotti, Gabriella

    2011-06-15

    A twofold generalization of the optical schemes that perform the discrete Fourier transform (DFT) is given: new passive planar architectures are presented where the 2 × 2 3 dB couplers are replaced by M × M hybrids, reducing the number of required connections and phase shifters. Furthermore, the planar implementation of the discrete fractional Fourier transform (DFrFT) is also described, with a waveguide grating router (WGR) configuration and a properly modified slab coupler.

  17. Optical Computing

    OpenAIRE

    Woods, Damien; Naughton, Thomas J.

    2008-01-01

    We consider optical computers that encode data using images and compute by transforming such images. We give an overview of a number of such optical computing architectures, including descriptions of the type of hardware commonly used in optical computing, as well as some of the computational efficiencies of optical devices. We go on to discuss optical computing from the point of view of computational complexity theory, with the aim of putting some old, and some very recent, re...

  18. Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

    Science.gov (United States)

    Woodruff, Steven D.; Mcintyre, Dustin L.

    2016-03-29

    A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

  19. The dynamical complexity of optically injected semiconductor lasers

    International Nuclear Information System (INIS)

    Wieczorek, S.; Krauskopf, B.; Simpson, T.B.; Lenstra, D.

    2005-01-01

    This report presents a modern approach to the theoretical and experimental study of complex nonlinear behavior of a semiconductor laser with optical injection-an example of a widely applied and technologically relevant forced nonlinear oscillator. We show that the careful bifurcation analysis of a rate equation model yields (i) a deeper understanding of already studied physical phenomena, and (ii) the discovery of new dynamical effects, such as multipulse excitability. Different instabilities, cascades of bifurcations, multistability, and sudden chaotic transitions, which are often viewed as independent, are in fact logically connected into a consistent web of bifurcations via special points called organizing centers. This theoretical bifurcation analysis has predictive power, which manifests itself in good agreement with experimental measurements over a wide range of parameters and diversity of dynamics. While it is dealing with the specific system of an optically injected laser, our work constitutes the state-of-the-art in the understanding and modeling of a nonlinear physical system in general

  20. Optical Coherent Receiver Enables THz Wireless Bridge

    DEFF Research Database (Denmark)

    Yu, Xianbin; Liu, Kexin; Zhang, Hangkai

    2016-01-01

    We experimentally demonstrated a 45 Gbit/s 400 GHz photonic wireless communication system enabled by an optical coherent receiver, which has a high potential in fast recovery of high data rate connections, for example, in disaster....

  1. Engineering Optics

    CERN Document Server

    Iizuka, Keigo

    2008-01-01

    Engineering Optics is a book for students who want to apply their knowledge of optics to engineering problems, as well as for engineering students who want to acquire the basic principles of optics. It covers such important topics as optical signal processing, holography, tomography, holographic radars, fiber optical communication, electro- and acousto-optic devices, and integrated optics (including optical bistability). As a basis for understanding these topics, the first few chapters give easy-to-follow explanations of diffraction theory, Fourier transforms, and geometrical optics. Practical examples, such as the video disk, the Fresnel zone plate, and many more, appear throughout the text, together with numerous solved exercises. There is an entirely new section in this updated edition on 3-D imaging.

  2. A systematic framework for functional connectivity measures

    Directory of Open Access Journals (Sweden)

    Huifang Elizabeth Wang

    2014-12-01

    Full Text Available Various methods have been proposed to characterize the functional connectivity between nodes in a network measured with different modalities (electrophysiology, functional magnetic resonance imaging etc.. Since different measures of functional connectivity yield different results for the same dataset, it is important to assess when and how they can be used. In this work, we provide a systematic framework for evaluating the performance of a large range of functional connectivity measures – based upon a comprehensive portfolio of models generating measurable responses. Specifically, we benchmarked 42 methods using 10,000 simulated datasets from 5 different types of generative models with different connectivity structures. Since all functional connectivity methods require the setting of some parameters (window size and number, model order etc., we first optimized these parameters using performance criteria based upon (threshold free ROC analysis. We then evaluated the performance of the methods on data simulated with different types of models. Finally, we assessed the performance of the methods against different levels of signal-to-noise ratios and network configurations. A MATLAB toolbox is provided to perform such analyses using other methods and simulated datasets.

  3. Optical response of bowtie antennas

    Science.gov (United States)

    Guo, Ying-Nan; Pan, Shi; Li, Xu-Feng; Wang, Shuo; Wang, Qiao

    2010-10-01

    Optical properties of bowtie antennas are investigated using a numerical method of finite-difference time-domain (FDTD). The optical response in the antenna feed gap is simulated as functions of its geometry parameters (flare angle, arm length, apex width, thickness, gap dimension, as well as the index of substrate), which provide a clear guideline to exploit such antenna structures in practice.

  4. Optical Storage and Optical Information Held in Taipei, Taiwan on 26-27 July 2000

    National Research Council Canada - National Science Library

    Shieh, H.-P. D

    2000-01-01

    .... In the area of data storage, topics include devices to improve the performance of optical heads, measurement of optical media parameters, new superresolution techniques, three-dimensional memory, and near-field devices...

  5. Electron optics

    CERN Document Server

    Grivet, Pierre; Bertein, F; Castaing, R; Gauzit, M; Septier, Albert L

    1972-01-01

    Electron Optics, Second English Edition, Part I: Optics is a 10-chapter book that begins by elucidating the fundamental features and basic techniques of electron optics, as well as the distribution of potential and field in electrostatic lenses. This book then explains the field distribution in magnetic lenses; the optical properties of electrostatic and magnetic lenses; and the similarities and differences between glass optics and electron optics. Subsequent chapters focus on lens defects; some electrostatic lenses and triode guns; and magnetic lens models. The strong focusing lenses and pris

  6. A super soliton connection

    International Nuclear Information System (INIS)

    Gurses, M.; Oguz, O.

    1985-07-01

    Integrable super non-linear classical partial differential equations are considered. A super s1(2,R) algebra valued connection 1-form is constructed. It is shown that curvature 2-form of this super connection vanishes by virtue of the integrable super equations of motion. A super extension of the AKNS scheme is presented and a class of super extension of the Lax hierarchy and super non-linear Schroedinger equation are found. O(N) extension and the Baecklund transformations of the above super equations are also considered. (author)

  7. Connecting textual segments

    DEFF Research Database (Denmark)

    Brügger, Niels

    2017-01-01

    history than just the years of the emergence of the web, the chapter traces the history of how segments of text have deliberately been connected to each other by the use of specific textual and media features, from clay tablets, manuscripts on parchment, and print, among others, to hyperlinks on stand......In “Connecting textual segments: A brief history of the web hyperlink” Niels Brügger investigates the history of one of the most fundamental features of the web: the hyperlink. Based on the argument that the web hyperlink is best understood if it is seen as another step in a much longer and broader...

  8. Best connected rectangular arrangements

    Directory of Open Access Journals (Sweden)

    Krishnendra Shekhawat

    2016-03-01

    Full Text Available It can be found quite often in the literature that many well-known architects have employed either the golden rectangle or the Fibonacci rectangle in their works. On contrary, it is rare to find any specific reason for using them so often. Recently, Shekhawat (2015 proved that the golden rectangle and the Fibonacci rectangle are one of the best connected rectangular arrangements and this may be one of the reasons for their high presence in architectural designs. In this work we present an algorithm that generates n-4 best connected rectangular arrangements so that the proposed solutions can be further used by architects for their designs.

  9. Multifunctional optical sensor

    NARCIS (Netherlands)

    2010-01-01

    The invention relates to a multifunctional optical sensor, having at least 2 areas which independently react to different input parameters, the sensor comprising a substrate and a polymeric layer comprising polymerized liquid crystal monomers having an ordered morphology, wherein the color, the

  10. Optical Polarizationin Biomedical Applications

    CERN Document Server

    Tuchin, Valery V; Zimnyakov, Dmitry A

    2006-01-01

    Optical Polarization in Biomedical Applications introduces key developments in optical polarization methods for quantitative studies of tissues, while presenting the theory of polarization transfer in a random medium as a basis for the quantitative description of polarized light interaction with tissues. This theory uses the modified transfer equation for Stokes parameters and predicts the polarization structure of multiple scattered optical fields. The backscattering polarization matrices (Jones matrix and Mueller matrix) important for noninvasive medical diagnostic are introduced. The text also describes a number of diagnostic techniques such as CW polarization imaging and spectroscopy, polarization microscopy and cytometry. As a new tool for medical diagnosis, optical coherent polarization tomography is analyzed. The monograph also covers a range of biomedical applications, among them cataract and glaucoma diagnostics, glucose sensing, and the detection of bacteria.

  11. Optical Access Networks

    Science.gov (United States)

    Zheng, Jun; Ansari, Nirwan

    2005-06-01

    Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

  12. Linear optics and quantum maps

    International Nuclear Information System (INIS)

    Aiello, A.; Puentes, G.; Woerdman, J. P.

    2007-01-01

    We present a theoretical analysis of the connection between classical polarization optics and quantum mechanics of two-level systems. First, we review the matrix formalism of classical polarization optics from a quantum information perspective. In this manner the passage from the Stokes-Jones-Mueller description of classical optical processes to the representation of one- and two-qubit quantum operations, becomes straightforward. Second, as a practical application of our classical-vs-quantum formalism, we show how two-qubit maximally entangled mixed states can be generated by using polarization and spatial modes of photons generated via spontaneous parametric down conversion

  13. Connections among quantum logics

    International Nuclear Information System (INIS)

    Lock, P.F.; Hardegree, G.M.

    1985-01-01

    This paper gives a brief introduction to the major areas of work in quantum event logics: manuals (Foulis and Randall) and semi-Boolean algebras (Abbott). The two theories are compared, and the connection between quantum event logics and quantum propositional logics is made explicit. In addition, the work on manuals provides us with many examples of results stated in Part I. (author)

  14. Connectivity measures: a review

    Czech Academy of Sciences Publication Activity Database

    Kindlmann, Pavel; Burel, F.

    2008-01-01

    Roč. 23, č. 1 (2008), s. 879-890 ISSN 0921-2973 R&D Projects: GA MŠk LC06073; GA AV ČR(CZ) IAA6087301 Institutional research plan: CEZ:AV0Z60870520 Keywords : Conservation biology * Habitat fragmentation * Landscape connectivity * Measures * Species extinction Subject RIV: EH - Ecology, Behaviour Impact factor: 2.453, year: 2008

  15. Clip, connect, clone

    DEFF Research Database (Denmark)

    Fujima, Jun; Lunzer, Aran; Hornbæk, Kasper

    2010-01-01

    using three mechanisms: clipping of input and result elements from existing applications to form cells on a spreadsheet; connecting these cells using formulas, thus enabling result transfer between applications; and cloning cells so that multiple requests can be handled side by side. We demonstrate...

  16. A Connective Pedagogy.

    Science.gov (United States)

    Goral, Mary

    2000-01-01

    Our increasingly hurried lifestyle, changes in family structure, and intense economic pressures place stress on children and families. Waldorf education provides an educational environment that alleviates this stress through a connective pedagogy that encompasses continuity of people, curriculum, and instruction; a reverence and respect for the…

  17. Connected vehicle application : safety.

    Science.gov (United States)

    2015-01-01

    Connected vehicle safety applications are designed to increase situational awareness : and reduce or eliminate crashes through vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and vehicle-to-pedestrian (V2P) data transmissions. Applications...

  18. Mathematics Connection: Editorial Policies

    African Journals Online (AJOL)

    Focus and Scope. MATHEMATICS CONNECTION aims at providing a forum to promote the development of Mathematics Education in Ghana. Articles that seek to enhance the teaching and/or learning of mathematics at all levels of the educational system are welcome ...

  19. Making the Connection

    Science.gov (United States)

    Perna, Mark C.

    2006-01-01

    Enrollment marketing is not just about enrollment; it is about creating relationships and serving one's community or target audience for many years. In this article, the author states that the first step in building such relationships is making a connection, and that is what effective marketing is all about. Administrators, teachers and critical…

  20. Connecting numeric models

    International Nuclear Information System (INIS)

    Caremoli, C.; Erhard, P.

    1996-01-01

    Computerized simulation uses calculation codes whose validation is reliable. Reactor simulators should take greater advantage of latest computer technology impact, in particular in the field of parallel processing. Instead of creating more global simulation codes whose validation might be a problem, connecting several existing codes should be a promising solution. (D.L.). 3 figs

  1. From connection to customer

    International Nuclear Information System (INIS)

    Milatz, H.; Soeters, R.

    2001-01-01

    Energy companies can no longer be certain that a customer today will remain a customer tomorrow. They have to work hard to achieve that. They are going from thinking in terms of connections to pampering their customers. Good Customer Relationship Management is a way to achieve a competitive advantage. The whole organisation has to adapt, particularly the customer orientation of employees

  2. Mapping functional connectivity

    Science.gov (United States)

    Peter Vogt; Joseph R. Ferrari; Todd R. Lookingbill; Robert H. Gardner; Kurt H. Riitters; Katarzyna Ostapowicz

    2009-01-01

    An objective and reliable assessment of wildlife movement is important in theoretical and applied ecology. The identification and mapping of landscape elements that may enhance functional connectivity is usually a subjective process based on visual interpretations of species movement patterns. New methods based on mathematical morphology provide a generic, flexible,...

  3. IDRC Connect User Guide

    International Development Research Centre (IDRC) Digital Library (Canada)

    Kristina Kamichaitis

    2 Jul 2015 ... IDRC Connect contribuye a la aplicación de la Política de Acceso abierto de IDRC facilitando ..... Tesis. • Material de capacitación. • Sitio web. • Documento de trabajo ..... incluir planes de estudios, metodologías y manuales.

  4. Display Parameters and Requirements

    Science.gov (United States)

    Bahadur, Birendra

    The following sections are included: * INTRODUCTION * HUMAN FACTORS * Anthropometry * Sensory * Cognitive * Discussions * THE HUMAN VISUAL SYSTEM - CAPABILITIES AND LIMITATIONS * Cornea * Pupil and Iris * Lens * Vitreous Humor * Retina * RODS - NIGHT VISION * CONES - DAY VISION * RODS AND CONES - TWILIGHT VISION * VISUAL PIGMENTS * MACULA * BLOOD * CHOROID COAT * Visual Signal Processing * Pathways to the Brain * Spatial Vision * Temporal Vision * Colour Vision * Colour Blindness * DICHROMATISM * Protanopia * Deuteranopia * Tritanopia * ANOMALOUS TRICHROMATISM * Protanomaly * Deuteranomaly * Tritanomaly * CONE MONOCHROMATISM * ROD MONOCHROMATISM * Using Colour Effectively * COLOUR MIXTURES AND THE CHROMATICITY DIAGRAM * Colour Matching Functions and Chromaticity Co-ordinates * CIE 1931 Colour Space * CIE PRIMARIES * CIE COLOUR MATCHING FUNCTIONS AND CHROMATICITY CO-ORDINATES * METHODS FOR DETERMINING TRISTIMULUS VALUES AND COLOUR CO-ORDINATES * Spectral Power Distribution Method * Filter Method * CIE 1931 CHROMATICITY DIAGRAM * ADDITIVE COLOUR MIXTURE * CIE 1976 Chromaticity Diagram * CIE Uniform Colour Spaces and Colour Difference Formulae * CIELUV OR L*u*v* * CIELAB OR L*a*b* * CIE COLOUR DIFFERENCE FORMULAE * Colour Temperature and CIE Standard Illuminants and source * RADIOMETRIC AND PHOTOMETRIC QUANTITIES * Photopic (Vλ and Scotopic (Vλ') Luminous Efficiency Function * Photometric and Radiometric Flux * Luminous and Radiant Intensities * Incidence: Illuminance and Irradiance * Exitance or Emittance (M) * Luminance and Radiance * ERGONOMIC REQUIREMENTS OF DISPLAYS * ELECTRO-OPTICAL PARAMETERS AND REQUIREMENTS * Contrast and Contrast Ratio * Luminance and Brightness * Colour Contrast and Chromaticity * Glare * Other Aspects of Legibility * SHAPE AND SIZE OF CHARACTERS * DEFECTS AND BLEMISHES * FLICKER AND DISTORTION * ANGLE OF VIEW * Switching Speed * Threshold and Threshold Characteristic * Measurement Techniques For Electro-optical Parameters * RADIOMETRIC

  5. Applied optics

    International Nuclear Information System (INIS)

    Orszag, A.; Antonetti, A.

    1988-01-01

    The 1988 progress report, of the Applied Optics laboratory, of the (Polytechnic School, France), is presented. The optical fiber activities are focused on the development of an optical gyrometer, containing a resonance cavity. The following domains are included, in the research program: the infrared laser physics, the laser sources, the semiconductor physics, the multiple-photon ionization and the nonlinear optics. Investigations on the biomedical, the biological and biophysical domains are carried out. The published papers and the congress communications are listed [fr

  6. A fiber optic link for the remote handling in nuclear environment

    International Nuclear Information System (INIS)

    Breuze, G.; Carnet, B.; Friant, A.; Blanc, F.; Lordet, J.; Boisde, G.

    1988-01-01

    At CEA a R/D program is running to improve performances of servomanipulators used in nuclear fuel reprocessing plants. Present work gives the main environmental parameters (gamma rays exposition, temperature) and shows the basis of the digital link designed to remote-handle such a manipulator. Up to 10 5 Gy behavior of optical fibers and electronic components was studied. Two different optical cables were built, one for the long link (100 m), the second to set in an especially designed winding unwinding wheel. Six way permanent or remote-handle connectors were developed to connect optical interfaces and a leaktight penetration. Measured budget of the link taking into account efficient photoblesching of the pure silica core fiber and influence of gamma rays on the slave interface is presented [fr

  7. Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

    International Nuclear Information System (INIS)

    Fialkov, A.; Loeb, A.

    2016-01-01

    The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we show that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.

  8. Constraining the CMB optical depth through the dispersion measure of cosmological radio transients

    Energy Technology Data Exchange (ETDEWEB)

    Fialkov, A.; Loeb, A., E-mail: anastasia.fialkov@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Institute for Teory and Computation, Harvard University, 60 Garden Street, MS-51, Cambridge, MA, 02138 (United States)

    2016-05-01

    The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we show that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.

  9. Integrated optical circuit comprising a polarization convertor

    NARCIS (Netherlands)

    1998-01-01

    An integrated optical circuit includes a first device and a second device, which devices are connected by a polarization convertor. The polarization convertor includes a curved section of a waveguide, integrated in the optical circuit. The curved section may have several differently curved

  10. Miniature mechanical transfer optical coupler

    Science.gov (United States)

    Abel, Philip [Overland Park, KS; Watterson, Carl [Kansas City, MO

    2011-02-15

    A miniature mechanical transfer (MT) optical coupler ("MMTOC") for optically connecting a first plurality of optical fibers with at least one other plurality of optical fibers. The MMTOC may comprise a beam splitting element, a plurality of collimating lenses, and a plurality of alignment elements. The MMTOC may optically couple a first plurality of fibers disposed in a plurality of ferrules of a first MT connector with a second plurality of fibers disposed in a plurality of ferrules of a second MT connector and a third plurality of fibers disposed in a plurality of ferrules of a third MT connector. The beam splitting element may allow a portion of each beam of light from the first plurality of fibers to pass through to the second plurality of fibers and simultaneously reflect another portion of each beam of light from the first plurality of fibers to the third plurality of fibers.

  11. Analysis of aggregate optical spectra using moments. Application to the purple membrane of halobacterium halobium

    International Nuclear Information System (INIS)

    Hemenger, R.P.

    1978-01-01

    The problem of extracting structural information from the optical spectra of aggregates of molecules interacting through their electronic transitions is studied. One serious difficulty common to all approaches to this problem is that of properly taking into account the effects of molecular vibrations. A series of exact relations derived previously which are correct with regard to molecular vibrations provide a number of independent, explicit connections between aggregate geometrical parameters and moments of experimental spectra. It is shown that, by applying these moment relations to the optical absorption and circular dichroism spectra of simple aggregates, a complete set of equations can be found, i.e., enough equations can be found to solve for all of the geometrical parameters which enter into the expressions for absorption and circular dichroism spectra. This procedure is applied in some detail to the purple membrane of Halobacterium halobium. The results are completely consistent with what is known about its structure

  12. Optical resonances in multilayer structures

    NARCIS (Netherlands)

    Maksimovic, Milan

    2008-01-01

    Theoretical research in optics may be divided in two distinctive but well connected general directions. The first deals with developing new or improving existing mathematical models to describe relevant physics. The second aims to predict new phenomena or applications using established models and

  13. Mapping cell-specific functional connections in the mouse brain using ChR2-evoked hemodynamics (Conference Presentation)

    Science.gov (United States)

    Bauer, Adam Q.; Kraft, Andrew; Baxter, Grant A.; Bruchas, Michael; Lee, Jin-Moo; Culver, Joseph P.

    2017-02-01

    Functional magnetic resonance imaging (fMRI) has transformed our understanding of the brain's functional organization. However, mapping subunits of a functional network using hemoglobin alone presents several disadvantages. Evoked and spontaneous hemodynamic fluctuations reflect ensemble activity from several populations of neurons making it difficult to discern excitatory vs inhibitory network activity. Still, blood-based methods of brain mapping remain powerful because hemoglobin provides endogenous contrast in all mammalian brains. To add greater specificity to hemoglobin assays, we integrated optical intrinsic signal(OIS) imaging with optogenetic stimulation to create an Opto-OIS mapping tool that combines the cell-specificity of optogenetics with label-free, hemoglobin imaging. Before mapping, titrated photostimuli determined which stimulus parameters elicited linear hemodynamic responses in the cortex. Optimized stimuli were then scanned over the left hemisphere to create a set of optogenetically-defined effective connectivity (Opto-EC) maps. For many sites investigated, Opto-EC maps exhibited higher spatial specificity than those determined using spontaneous hemodynamic fluctuations. For example, resting-state functional connectivity (RS-FC) patterns exhibited widespread ipsilateral connectivity while Opto-EC maps contained distinct short- and long-range constellations of ipsilateral connectivity. Further, RS-FC maps were usually symmetric about midline while Opto-EC maps displayed more heterogeneous contralateral homotopic connectivity. Both Opto-EC and RS-FC patterns were compared to mouse connectivity data from the Allen Institute. Unlike RS-FC maps, Thy1-based maps collected in awake, behaving mice closely recapitulated the connectivity structure derived using ex vivo anatomical tracer methods. Opto-OIS mapping could be a powerful tool for understanding cellular and molecular contributions to network dynamics and processing in the mouse brain.

  14. Generalizing optical geometry

    International Nuclear Information System (INIS)

    Jonsson, Rickard; Westman, Hans

    2006-01-01

    We show that by employing the standard projected curvature as a measure of spatial curvature, we can make a certain generalization of optical geometry (Abramowicz M A and Lasota J-P 1997 Class. Quantum Grav. A 14 23-30). This generalization applies to any spacetime that admits a hypersurface orthogonal shearfree congruence of worldlines. This is a somewhat larger class of spacetimes than the conformally static spacetimes assumed in standard optical geometry. In the generalized optical geometry, which in the generic case is time dependent, photons move with unit speed along spatial geodesics and the sideways force experienced by a particle following a spatially straight line is independent of the velocity. Also gyroscopes moving along spatial geodesics do not precess (relative to the forward direction). Gyroscopes that follow a curved spatial trajectory precess according to a very simple law of three-rotation. We also present an inertial force formalism in coordinate representation for this generalization. Furthermore, we show that by employing a new sense of spatial curvature (Jonsson R 2006 Class. Quantum Grav. 23 1)) closely connected to Fermat's principle, we can make a more extensive generalization of optical geometry that applies to arbitrary spacetimes. In general this optical geometry will be time dependent, but still geodesic photons move with unit speed and follow lines that are spatially straight in the new sense. Also, the sideways experienced (comoving) force on a test particle following a line that is straight in the new sense will be independent of the velocity

  15. Supervised hub-detection for brain connectivity

    DEFF Research Database (Denmark)

    Kasenburg, Niklas; Liptrot, Matthew George; Reislev, Nina Linde

    2016-01-01

    , but can smooth discriminative signals in the population, degrading predictive performance. We present a novel hub-detection optimized for supervised learning that both clusters network nodes based on population level variation in connectivity and also takes the learning problem into account. The found......A structural brain network consists of physical connections between brain regions. Brain network analysis aims to find features associated with a parameter of interest through supervised prediction models such as regression. Unsupervised preprocessing steps like clustering are often applied...... hubs are a low-dimensional representation of the network and are chosen based on predictive performance as features for a linear regression. We apply our method to the problem of finding age-related changes in structural connectivity. We compare our supervised hub-detection (SHD) to an unsupervised hub...

  16. Fluidic optics

    Science.gov (United States)

    Whitesides, George M.; Tang, Sindy K. Y.

    2006-09-01

    Fluidic optics is a new class of optical system with real-time tunability and reconfigurability enabled by the introduction of fluidic components into the optical path. We describe the design, fabrication, operation of a number of fluidic optical systems, and focus on three devices, liquid-core/liquid-cladding (L2) waveguides, microfluidic dye lasers, and diffraction gratings based on flowing, crystalline lattices of bubbles, to demonstrate the integration of microfluidics and optics. We fabricate these devices in poly(dimethylsiloxane) (PDMS) with soft-lithographic techniques. They are simple to construct, and readily integrable with microanalytical or lab-on-a-chip systems.

  17. Optical fibres

    CERN Document Server

    Geisler, J; Boutruche, J P

    1986-01-01

    Optical Fibers covers numerous research works on the significant advances in optical fibers, with particular emphasis on their application.This text is composed of three parts encompassing 15 chapters. The first part deals with the manufacture of optical fibers and the materials used in their production. The second part describes optical-fiber connectors, terminals and branches. The third part is concerned with the major optoelectronic components encountered in optical-communication systems.This book will be of value to research scientists, engineers, and patent workers.

  18. Atom optics

    International Nuclear Information System (INIS)

    Balykin, V. I.; Jhe, W.

    1999-01-01

    Atom optics, in analogy to neutron and electron optics, deals with the realization of as a traditional elements, such as lenes, mirrors, beam splitters and atom interferometers, as well as a new 'dissipative' elements such as a slower and a cooler, which have no analogy in an another types of optics. Atom optics made the development of atom interferometer with high sensitivity for measurement of acceleration and rotational possible. The practical interest in atom optics lies in the opportunities to create atom microprobe with atom-size resolution and minimum damage of investigated objects. (Cho, G. S.)

  19. Optical interconnects

    CERN Document Server

    Chen, Ray T

    2006-01-01

    This book describes fully embedded board level optical interconnect in detail including the fabrication of the thin-film VCSEL array, its characterization, thermal management, the fabrication of optical interconnection layer, and the integration of devices on a flexible waveguide film. All the optical components are buried within electrical PCB layers in a fully embedded board level optical interconnect. Therefore, we can save foot prints on the top real estate of the PCB and relieve packaging difficulty reduced by separating fabrication processes. To realize fully embedded board level optical

  20. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q