WorldWideScience

Sample records for incident light fields

  1. Time-dependent scattering of incident light of various wavelengths in ferrofluids under external magnetic field

    Science.gov (United States)

    Jin, Jingyu; Song, Dongxing; Geng, Jiafeng; Jing, Dengwei

    2018-02-01

    Ferrofluids can exhibit the anisotropic thermodynamic properties under magnetic fields. The dynamic optical properties of ferrofluids in the presence of magnetic fields are of particular interest due to their potential application as various optical devices. Although time-dependent light scattering by ferrofluids have been extensively studied, the effect of wavelength of incident light have been rarely considered. Here, for the first time, we investigated both the time- and wavelength-dependent light scattering in water based ferrofluids containing Fe3O4 nanoparticles under an external magnetic field. The field-induced response behavior of the prepared ferrofluid samples was determined and verified first by thermal conductivity measurement and numerical simulation. Double-beam UV-Vis spectrophotometer was employed to record the temporal evolution of transmitted intensity of incident light of various wavelengths passing through the ferrofluid sample and propagating parallel to the applied field. As expected, the light intensity decreases to a certain value right after the field is turned on due to the thermal fluctuation induced disorder inside the flexible particle chains. Then the light intensity further decreases with time until the appearance of a minimum at time τ0 followed by an inversed increase before finally reaches equilibrium at a particular time. More importantly, the characteristic inversion time τ0 was found to follow a power law increase with the wavelength of incident light (τ0 ∼ λα, where α = 2.07). A quantitative explanation for the wavelength dependence of characteristic time was proposed based on the finite-difference time-domain (FDTD) method. The simulation results are in good agreement with our experimental observations. The time-dependent light scattering in ferrofluids under different incident wavelengths was rationalized by considering both the coarsening process of the particle chains and the occurrence of resonance within the

  2. Theory and analysis of a large field polarization imaging system with obliquely incident light.

    Science.gov (United States)

    Lu, Xiaotian; Jin, Weiqi; Li, Li; Wang, Xia; Qiu, Su; Liu, Jing

    2018-02-05

    Polarization imaging technology provides information about not only the irradiance of a target but also the polarization degree and angle of polarization, which indicates extensive application potential. However, polarization imaging theory is based on paraxial optics. When a beam of obliquely incident light passes an analyser, the direction of light propagation is not perpendicular to the surface of the analyser and the applicability of the traditional paraxial optical polarization imaging theory is challenged. This paper investigates a theoretical model of a polarization imaging system with obliquely incident light and establishes a polarization imaging transmission model with a large field of obliquely incident light. In an imaging experiment with an integrating sphere light source and rotatable polarizer, the polarization imaging transmission model is verified and analysed for two cases of natural light and linearly polarized light incidence. Although the results indicate that the theoretical model is consistent with the experimental results, the theoretical model distinctly differs from the traditional paraxial approximation model. The results prove the accuracy and necessity of the theoretical model and the theoretical guiding significance for theoretical and systematic research of large field polarization imaging.

  3. Effects of a power and photon energy of incident light on near-field etching properties

    Science.gov (United States)

    Yatsui, T.; Saito, H.; Nishioka, K.; Leuschel, B.; Soppera, O.; Nobusada, K.

    2017-12-01

    We developed a near-field etching technique for realizing an ultra-flat surfaces of various materials and structures. To elucidate the near-field etching properties, we have investigated the effects of power and the photon energy of the incident light. First, we established theoretically that an optical near-field with photon energy lower than the absorption edge of the molecules can induce molecular vibrations. We used nanodiamonds to study the power dependence of the near-field etching properties. From the topological changes of the nanodiamonds, we confirmed the linear-dependence of the etching volume with the incident power. Furthermore, we studied the photon energy dependence using TiO2 nanostriped structures, which revealed that a lower photon energy results in a lower etching rate.

  4. Generation of an incident focused light pulse in FDTD.

    Science.gov (United States)

    Capoğlu, Ilker R; Taflove, Allen; Backman, Vadim

    2008-11-10

    A straightforward procedure is described for accurately creating an incident focused light pulse in the 3-D finite-difference time-domain (FDTD) electromagnetic simulation of the image space of an aplanatic converging lens. In this procedure, the focused light pulse is approximated by a finite sum of plane waves, and each plane wave is introduced into the FDTD simulation grid using the total-field/scattered-field (TF/SF) approach. The accuracy of our results is demonstrated by comparison with exact theoretical formulas.

  5. Light Field Photography A Survey

    Directory of Open Access Journals (Sweden)

    M Zulkifl Hasan

    2017-01-01

    Full Text Available In this survey author will be discussing about light field photography its importance techniques used in it to have an excellent output from the normal cameras. Light field photography has become an emerging area due to its refocusing of digital image and 3D reconstruction. Reconstruction of image tells us about its high resolution and refocusing is used to clear the blur image.1

  6. Light field morphing using 2D features.

    Science.gov (United States)

    Wang, Lifeng; Lin, Stephen; Lee, Seungyong; Guo, Baining; Shum, Heung-Yeung

    2005-01-01

    We present a 2D feature-based technique for morphing 3D objects represented by light fields. Existing light field morphing methods require the user to specify corresponding 3D feature elements to guide morph computation. Since slight errors in 3D specification can lead to significant morphing artifacts, we propose a scheme based on 2D feature elements that is less sensitive to imprecise marking of features. First, 2D features are specified by the user in a number of key views in the source and target light fields. Then the two light fields are warped view by view as guided by the corresponding 2D features. Finally, the two warped light fields are blended together to yield the desired light field morph. Two key issues in light field morphing are feature specification and warping of light field rays. For feature specification, we introduce a user interface for delineating 2D features in key views of a light field, which are automatically interpolated to other views. For ray warping, we describe a 2D technique that accounts for visibility changes and present a comparison to the ideal morphing of light fields. Light field morphing based on 2D features makes it simple to incorporate previous image morphing techniques such as nonuniform blending, as well as to morph between an image and a light field.

  7. Beebook: light field mapping app

    Science.gov (United States)

    De Donatis, Mauro; Di Pietro, Gianfranco; Rinnone, Fabio

    2014-05-01

    In the last decade the mobile systems for field digital mapping were developed (see Wikipedia for "Digital geologic mapping"), also against many skeptic traditional geologists. Until now, hardware was often heavy (tablet PC) and software sometime difficult also for expert GIS users. At present, the advent of light tablet and applications makes things easier, but we are far to find a whole solution for a complex survey like the geological one where you have to manage complexities such information, hypothesis, data, interpretation. Beebook is a new app for Android devices, has been developed for fast ad easy mapping work in the field trying to try to solve this problem. The main features are: • off-line raster management, GeoTIFF ed other raster format using; • on-line map visualisation (Google Maps, OSM, WMS, WFS); • SR management and conversion using PROJ.4; • vector file mash-up (KML and SQLite format); • editing of vector data on the map (lines, points, polygons); • augmented reality using "Mixare" platform; • export of vector data in KML, CSV, SQLite (Spatialite) format; • note: GPS or manual point inserting linked to other application files (pictures, spreadsheet, etc.); • form: creation, edition and filling of customized form; • GPS: status control, tracker and positioning on map; • sharing: synchronization and sharing of data, forms, positioning and other information can be done among users. The input methods are different from digital keyboard to fingers touch, from voice recording to stylus. In particular the most efficient way of inserting information is the stylus (or pen): field geologists are familiar with annotation and sketches. Therefore we suggest the use of devices with stylus. The main point is that Beebook is the first "transparent" mobile GIS for tablet and smartphone deriving from previous experience as traditional mapping and different previous digital mapping software ideation and development (MapIT, BeeGIS, Geopaparazzi

  8. Face Liveness Detection Using a Light Field Camera

    Directory of Open Access Journals (Sweden)

    Sooyeon Kim

    2014-11-01

    Full Text Available A light field camera is a sensor that can record the directions as well as the colors of incident rays. This camera is widely utilized from 3D reconstruction to face and iris recognition. In this paper, we suggest a novel approach for defending spoofing face attacks, like printed 2D facial photos (hereinafter 2D photos and HD tablet images, using the light field camera. By viewing the raw light field photograph from a different standpoint, we extract two special features which cannot be obtained from the conventional camera. To verify the performance, we compose light field photograph databases and conduct experiments. Our proposed method achieves at least 94.78% accuracy or up to 99.36% accuracy under different types of spoofing attacks.

  9. Characterization of Partially Polarized Light Fields

    CERN Document Server

    Martínez-Herrero, Rosario; Piquero, Gemma

    2009-01-01

    Polarization involves the vectorial nature of light fields. In current applications of optical science, the electromagnetic description of light with its vector features has been shown to be essential: In practice, optical radiation also exhibits randomness and spatial non-uniformity of the polarization state. Moreover, propagation through photonic devices can alter the correlation properties of the light field, resulting in changes in polarization. All these vectorial properties have been gaining importance in recent years, and they are attracting increasing attention in the literature. This is the framework and the scope of the present book, which includes the authors’ own contributions to these issues.

  10. Demise of light cone field theory

    International Nuclear Information System (INIS)

    Hagen, C.R.

    1977-01-01

    It is shown that the massive spin one-half field is noncovariant in two dimensional light cone coordinates. It is shown that spin one-half is noncovariant in four dimensions as well. It is concluded that since the case of the spin one-half field is an absolute necessity if one is to build a world containing fermions. It seems safe to infer that light cone quantization cannot be useful in the quark binding problem as currently conceived. It is suggested that further work on light cone quantization be focused solely upon the questions of consistency as discussed rather than on applications to model building. 9 references

  11. Light-field-driven currents in graphene

    Science.gov (United States)

    Higuchi, Takuya; Heide, Christian; Ullmann, Konrad; Weber, Heiko B.; Hommelhoff, Peter

    2017-10-01

    The ability to steer electrons using the strong electromagnetic field of light has opened up the possibility of controlling electron dynamics on the sub-femtosecond (less than 10-15 seconds) timescale. In dielectrics and semiconductors, various light-field-driven effects have been explored, including high-harmonic generation, sub-optical-cycle interband population transfer and the non-perturbative change of the transient polarizability. In contrast, much less is known about light-field-driven electron dynamics in narrow-bandgap systems or in conductors, in which screening due to free carriers or light absorption hinders the application of strong optical fields. Graphene is a promising platform with which to achieve light-field-driven control of electrons in a conducting material, because of its broadband and ultrafast optical response, weak screening and high damage threshold. Here we show that a current induced in monolayer graphene by two-cycle laser pulses is sensitive to the electric-field waveform, that is, to the exact shape of the optical carrier field of the pulse, which is controlled by the carrier-envelope phase, with a precision on the attosecond (10-18 seconds) timescale. Such a current, dependent on the carrier-envelope phase, shows a striking reversal of the direction of the current as a function of the driving field amplitude at about two volts per nanometre. This reversal indicates a transition of light-matter interaction from the weak-field (photon-driven) regime to the strong-field (light-field-driven) regime, where the intraband dynamics influence interband transitions. We show that in this strong-field regime the electron dynamics are governed by sub-optical-cycle Landau-Zener-Stückelberg interference, composed of coherent repeated Landau-Zener transitions on the femtosecond timescale. Furthermore, the influence of this sub-optical-cycle interference can be controlled with the laser polarization state. These coherent electron dynamics in

  12. The Fresnel Zone Light Field Spectral Imager

    Science.gov (United States)

    2017-03-23

    detection efficiency for weak signals . Additionally, further study should be done on spectral calibration methods for a FZLFSI. When dealing with weak ... detection assembly. The different image formation planes for each wavelength are constructed synthetically through processing the collected light ...a single micro-lens image. This character- istic also holds for wavelengths other than the design wavelength. 36 modified light field PSF is detected

  13. Incident Light Frequency-Based Image Defogging Algorithm

    Directory of Open Access Journals (Sweden)

    Wenbo Zhang

    2017-01-01

    Full Text Available To solve the color distortion problem produced by the dark channel prior algorithm, an improved method for calculating transmittance of all channels, respectively, was proposed in this paper. Based on the Beer-Lambert Law, the influence between the frequency of the incident light and the transmittance was analyzed, and the ratios between each channel’s transmittance were derived. Then, in order to increase efficiency, the input image was resized to a smaller size before acquiring the refined transmittance which will be resized to the same size of original image. Finally, all the transmittances were obtained with the help of the proportion between each color channel, and then they were used to restore the defogging image. Experiments suggest that the improved algorithm can produce a much more natural result image in comparison with original algorithm, which means the problem of high color saturation was eliminated. What is more, the improved algorithm speeds up by four to nine times compared to the original algorithm.

  14. Magnetic field sensor for isotropically sensing an incident magnetic field in a sensor plane

    Science.gov (United States)

    Pant, Bharat B. (Inventor); Wan, Hong (Inventor)

    2001-01-01

    A magnetic field sensor that isotropically senses an incident magnetic field. This is preferably accomplished by providing a magnetic field sensor device that has one or more circular shaped magnetoresistive sensor elements for sensing the incident magnetic field. The magnetoresistive material used is preferably isotropic, and may be a CMR material or some form of a GMR material. Because the sensor elements are circular in shape, shape anisotropy is eliminated. Thus, the resulting magnetic field sensor device provides an output that is relatively independent of the direction of the incident magnetic field in the sensor plane.

  15. Light field imaging and application analysis in THz

    Science.gov (United States)

    Zhang, Hongfei; Su, Bo; He, Jingsuo; Zhang, Cong; Wu, Yaxiong; Zhang, Shengbo; Zhang, Cunlin

    2018-01-01

    The light field includes the direction information and location information. Light field imaging can capture the whole light field by single exposure. The four-dimensional light field function model represented by two-plane parameter, which is proposed by Levoy, is adopted in the light field. Acquisition of light field is based on the microlens array, camera array and the mask. We calculate the dates of light-field to synthetize light field image. The processing techniques of light field data include technology of refocusing rendering, technology of synthetic aperture and technology of microscopic imaging. Introducing the technology of light field imaging into THz, the efficiency of 3D imaging is higher than that of conventional THz 3D imaging technology. The advantages compared with visible light field imaging include large depth of field, wide dynamic range and true three-dimensional. It has broad application prospects.

  16. Measurement of incident sound power using near field acoustic holography

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Tiana Roig, Elisabet

    2009-01-01

    ; and it has always been regarded as impossible to measure the sound power that is incident on a wall directly. This paper examines a new method of determining this quantity from sound pressure measurements at positions on the wall using ‘statistically optimised near field acoustic holography’ (SONAH...

  17. Light front field theory: an advanced primer

    International Nuclear Information System (INIS)

    Martinovic, L.

    2007-01-01

    We present an elementary introduction to quantum field theory formulated in terms of Dirac's light front variables. In addition to general principles and methods, a few more specific topics and approaches based on the author's work will be discussed. Most of the discussion deals with massive two-dimensional models formulated in a finite spatial volume starting with a detailed comparison between quantization of massive free fields in the usual field theory and the light front (LF) quantization. We discuss basic properties such as relativistic invariance and causality. After the LF treatment of the soluble Federbush model, a LF approach to spontaneous symmetry breaking is explained and a simple gauge theory - the massive Schwinger model in various gauges is studied. A LF version of bosonization and the massive Thirring model are also discussed. A special chapter is devoted to the method of discretized light cone quantization and its application to calculations of the properties of quantum solitons. The problem of LF zero modes is illustrated with the example of the two/dimensional Yukawa model. Hamiltonian perturbation theory in the LF formulation is derived and applied to a few simple processes to demonstrate its advantages. As a byproduct, it is shown that the LF theory cannot be obtained as a 'light-like' limit of the usual field theory quantized on a initial space-like surface. A simple LF formulation of the Higgs mechanism is then given Since our intention was to provide a treatment of the light front quantization accessible to postgradual students, an effort was made to discuss most of the topics pedagogically and number of technical details and derivations are contained in the appendices (Author)

  18. Light-front quantization of field theory

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Prem P. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1996-07-01

    Some basic topics in Light-Front (LF) quantized field theory are reviewed. Poincare algebra and the LF spin operator are discussed. The local scalar field theory of the conventional framework is shown to correspond to a non-local Hamiltonian theory on the LF in view of the constraint equations on the phase space, which relate the bosonic condensates to the non-zero modes. This new ingredient is useful to describe the spontaneous symmetry breaking on the LF. The instability of the symmetric phase in two dimensional scalar theory when the coupling constant grows is shown in the LF theory renormalized to one loop order. Chern-Simons gauge theory, regarded to describe excitations with fractional statistics, is quantized in the light-cone gauge and a simple LF Hamiltonian obtained which may allow us to construct renormalized theory of anyons. (author). 20 refs.

  19. Light-front quantization of field theory

    International Nuclear Information System (INIS)

    Srivastava, Prem P.

    1996-07-01

    Some basic topics in Light-Front (LF) quantized field theory are reviewed. Poincare algebra and the LF spin operator are discussed. The local scalar field theory of the conventional framework is shown to correspond to a non-local Hamiltonian theory on the LF in view of the constraint equations on the phase space, which relate the bosonic condensates to the non-zero modes. This new ingredient is useful to describe the spontaneous symmetry breaking on the LF. The instability of the symmetric phase in two dimensional scalar theory when the coupling constant grows is shown in the LF theory renormalized to one loop order. Chern-Simons gauge theory, regarded to describe excitations with fractional statistics, is quantized in the light-cone gauge and a simple LF Hamiltonian obtained which may allow us to construct renormalized theory of anyons. (author). 20 refs

  20. Laser light absorption and harmonic generation due to self-generated magnetic fields

    International Nuclear Information System (INIS)

    Kruer, W.L.; Estabrook, K.G.

    1977-01-01

    It is shown that self-generated magnetic fields can play a significant role in laser light absorption. Even normally incident light will then be resonantly absorbed. Computer simulations and theoretical estimates for this absorption and the concomitant harmonic generation are given for parameters characteristic of some recent experiments

  1. Incidence, risk factors, and morphology in operating microscope light retinopathy

    International Nuclear Information System (INIS)

    Khwarg, S.G.; Linstone, F.A.; Daniels, S.A.; Isenberg, S.J.; Hanscom, T.A.; Geoghegan, M.; Straatsma, B.R.

    1987-01-01

    A review of 135 consecutive cataract operations identified ten cases (7.4%) of operating microscope light retinopathy. Ophthalmoscopically, these light retinopathy lesions appeared as a focal pigment epithelial change with varying degrees of pigment clumping in the center. Fluorescein angiography accentuated the lesion by demonstrating a sharply demarcated transmission defect, occasionally with multiple satellite lesions. The shape of the lesion matched the shape of the illuminating source of the particular operating microscope used during the surgery. The most significant risk factor associated with the production of these light retinopathy lesions was prolonged operating time. Mean total operating time for the ten patients with light retinopathy was 51 minutes longer than for those without (P less than .0001). Other significant associated factors were the presence of diabetes mellitus (P less than .03), younger age (P less than .05), and the use of hydrochlorothiazide (P less than .04)

  2. Resonance broadening in an intense light field

    International Nuclear Information System (INIS)

    Andreev, S.P.; Lisitsa, V.S.

    1977-01-01

    Collisions of identical atoms in a strong resonance radiation field E 0 cosωt, for which the atomic oscillation period is comparable to the collision time of the atoms, are considered. The problem is treated in terms of the simplest two-level atomic model. The problem of light absorption in such collisions is reduced to the problem of inelastic transitions in a three-level compound system of two atoms and an electromagnetic field. Corresponding probabilities and inelastic scattering integral cross sections for transitions between energy levels in such a system are calculated for two extreme cases- the impact (rapid collisions) and the static one (slow collisions). In the general case the cross sections depend nonlinearly on Esub(0). For small Esub(0) as compared to a certain critical Esub(0)* the results are similar to those of the well-known linear theory of resonance broadening. For Esub(0)>>Esub(0)* the absorption in the line wing is found to decrease (with increase of Esub(0)-the medium becomes more ''transparent''). The kinetics of light absorption in the medium of identical atoms with constant absorption capacity is analysed

  3. Goos-Hänchen shift of partially coherent light fields in epsilon-near-zero metamaterials

    Science.gov (United States)

    Ziauddin; Chuang, You-Lin; Qamar, Sajid; Lee, Ray-Kuang

    2016-05-01

    The Goos-Hänchen (GH) shifts in the reflected light are investigated both for p and s polarized partial coherent light beams incident on epsilon-near-zero (ENZ) metamaterials. In contrary to the coherent counterparts, the magnitude of GH shift becomes non-zero for p polarized partial coherent light beam; while GH shift can be relatively large with a small degree of spatial coherence for s polarized partial coherent beam. Dependence on the beam width and the permittivity of ENZ metamaterials is also revealed for partial coherent light fields. Our results on the GH shifts provide a direction on the applications for partial coherent light sources in ENZ metamaterials.

  4. Visual verification of linac light and radiation fields coincidence

    International Nuclear Information System (INIS)

    Monti, Angelo F.; Frigerio, Milena; Frigerio, Giovanna

    2003-01-01

    X-ray and light field alignment evaluation is carried out during linac quality assurance programs. In this paper, we compare the size of the light field measured by a photodiode and by a more traditional visual observation with the size of the x-ray field. The comparison between actual light field size, measured with the photodiode, and light field size measured by human eye allow us to verify the reliability of human eye in the evaluation of this parameter. The visual field is always larger than real light field; however, it agrees better with the x-ray field. It matches the light field if we take into account the 25% (± 1%) of the decrement line of the maximum central lightening; however, this method simulates better the actual field employed in radiation treatments

  5. Three-dimensional polarization states of monochromatic light fields.

    Science.gov (United States)

    Azzam, R M A

    2011-11-01

    The 3×1 generalized Jones vectors (GJVs) [E(x) E(y) E(z)](t) (t indicates the transpose) that describe the linear, circular, and elliptical polarization states of an arbitrary three-dimensional (3-D) monochromatic light field are determined in terms of the geometrical parameters of the 3-D vibration of the time-harmonic electric field. In three dimensions, there are as many distinct linear polarization states as there are points on the surface of a hemisphere, and the number of distinct 3-D circular polarization states equals that of all two-dimensional (2-D) polarization states on the Poincaré sphere, of which only two are circular states. The subset of 3-D polarization states that results from the superposition of three mutually orthogonal x, y, and z field components of equal amplitude is considered as a function of their relative phases. Interesting contours of equal ellipticity and equal inclination of the normal to the polarization ellipse with respect to the x axis are obtained in 2-D phase space. Finally, the 3×3 generalized Jones calculus, in which elastic scattering (e.g., by a nano-object in the near field) is characterized by the 3-D linear transformation E(s)=T E(i), is briefly introduced. In such a matrix transformation, E(i) and E(s) are the 3×1 GJVs of the incident and scattered waves and T is the 3×3 generalized Jones matrix of the scatterer at a given frequency and for given directions of incidence and scattering.

  6. Application of the weighted total field-scattering field technique to 3D-PSTD light scattering model

    Science.gov (United States)

    Hu, Shuai; Gao, Taichang; Liu, Lei; Li, Hao; Chen, Ming; Yang, Bo

    2018-04-01

    PSTD (Pseudo Spectral Time Domain) is an excellent model for the light scattering simulation of nonspherical aerosol particles. However, due to the particularity of its discretization form of the Maxwell's equations, the traditional Total Field/Scattering Field (TF/SF) technique for FDTD (Finite Differential Time Domain) is not applicable to PSTD, and the time-consuming pure scattering field technique is mainly applied to introduce the incident wave. To this end, the weighted TF/SF technique proposed by X. Gao is generalized and applied to the 3D-PSTD scattering model. Using this technique, the incident light can be effectively introduced by modifying the electromagnetic components in an inserted connecting region between the total field and the scattering field region with incident terms, where the incident terms are obtained by weighting the incident field by a window function. To optimally determine the thickness of connection region and the window function type for PSTD calculations, their influence on the modeling accuracy is firstly analyzed. To further verify the effectiveness and advantages of the weighted TF/SF technique, the improved PSTD model is validated against the PSTD model equipped with pure scattering field technique in both calculation accuracy and efficiency. The results show that, the performance of PSTD seems to be not sensitive to variation of window functions. The number of the connection layer required decreases with the increasing of spatial resolution, where for spatial resolution of 24 grids per wavelength, a 6-layer region is thick enough. The scattering phase matrices and integral scattering parameters obtained by the improved PSTD show an excellent consistency with those well-tested models for spherical and nonspherical particles, illustrating that the weighted TF/SF technique can introduce the incident precisely. The weighted TF/SF technique shows higher computational efficiency than pure scattering technique.

  7. Light robotics: a new field of research

    DEFF Research Database (Denmark)

    Engay, Einstom; Chouliara, Manto; Bañas, Andrew

    2018-01-01

    After years of working on light-driven trapping and manipulation, we can see that a confluence of developments is now ripe for the emergence of a new area that can contribute to nanobiophotonics - Light Robotics - which combines advances in microfabrication and optical micromanipulation together...... with intelligent control ideas from robotics, wavefront engineering and information optics. In the Summer 2017 we are publishing a 482 pages edited Elsevier book volume covering the fundamental aspects needed for Light Robotics including optical trapping systems, microfabrication and microassembly as well...... as underlying theoretical principles and experimental illustrations for optimizing optical forces and torques for Light Robotics...

  8. Measuring incident light on grape clusters using photosensitive paper and image analysis

    International Nuclear Information System (INIS)

    Price, S.F.; Schuette, M.L.; Tassie, E.

    1995-01-01

    Digital imaging and analysis was used to quantify and characterize the light exposure patterns of photosensitive paper tubes placed in representative cluster positions in two grape (Vitis vinifera L.) canopies: a minimally pruned and a vertically trained canopy. Blue pixel values of the captured images had a negative correlation with the log of irradiance from an integrating quantum sensor (r2 = 0.9308). The spectral response of the photosensitive paper was not measured. Histograms of incident light distribution on individual paper tubes were developed using imaging software. Histograms were able to quantify the distribution of incident light on individual tubes and were clearly related to the tube's exposure in the canopy. Average population curves of pixel light distribution of 20 tubes in each canopy were able to differentiate the typical cluster light environment in the two canopies. Tubes in the minimally pruned canopy had a larger proportion of their surface exposed to irradiances > 50 micromoles.s-1 m-2 and 65% higher average irradiance than the vertical canopy. Image analysis of photosensitive paper appears to be a workable method to record the distribution of incident light in plant canopies and may have utility in a range of ecological studies

  9. Light Field Rendering for Head Mounted Displays using Pixel Reprojection

    DEFF Research Database (Denmark)

    Hansen, Anne Juhler; Klein, Jákup; Kraus, Martin

    2017-01-01

    Light field displays have advantages over traditional stereoscopic head mounted displays, for example, because they can overcome the vergence-accommodation conflict. However, rendering light fields can be a heavy task for computers due to the number of images that have to be rendered. Since much ...

  10. External Mask Based Depth and Light Field Camera

    Science.gov (United States)

    2013-12-08

    External mask based depth and light field camera Dikpal Reddy NVIDIA Research Santa Clara, CA dikpalr@nvidia.com Jiamin Bai University of California...passive depth acquisition technology is illustrated by the emergence of light field camera companies like Lytro [1], Raytrix [2] and Pelican Imaging

  11. High Incidence of Breast Cancer in Light-Polluted Areas with Spatial Effects in Korea.

    Science.gov (United States)

    Kim, Yun Jeong; Park, Man Sik; Lee, Eunil; Choi, Jae Wook

    2016-01-01

    We have reported a high prevalence of breast cancer in light-polluted areas in Korea. However, it is necessary to analyze the spatial effects of light polluted areas on breast cancer because light pollution levels are correlated with region proximity to central urbanized areas in studied cities. In this study, we applied a spatial regression method (an intrinsic conditional autoregressive [iCAR] model) to analyze the relationship between the incidence of breast cancer and artificial light at night (ALAN) levels in 25 regions including central city, urbanized, and rural areas. By Poisson regression analysis, there was a significant correlation between ALAN, alcohol consumption rates, and the incidence of breast cancer. We also found significant spatial effects between ALAN and the incidence of breast cancer, with an increase in the deviance information criterion (DIC) from 374.3 to 348.6 and an increase in R2 from 0.574 to 0.667. Therefore, spatial analysis (an iCAR model) is more appropriate for assessing ALAN effects on breast cancer. To our knowledge, this study is the first to show spatial effects of light pollution on breast cancer, despite the limitations of an ecological study. We suggest that a decrease in ALAN could reduce breast cancer more than expected because of spatial effects.

  12. Twisted-Light-Ion Interaction: The Role of Longitudinal Fields

    Science.gov (United States)

    Quinteiro, G. F.; Schmidt-Kaler, Ferdinand; Schmiegelow, Christian T.

    2017-12-01

    The propagation of light beams is well described using the paraxial approximation, where field components along the propagation direction are usually neglected. For strongly inhomogeneous or shaped light fields, however, this approximation may fail, leading to intriguing variations of the light-matter interaction. This is the case of twisted light having opposite orbital and spin angular momenta. We compare experimental data for the excitation of a quadrupole transition in a single trapped 40Ca+ ion from Schmiegelow et al. [Nat. Commun. 7, 12998 (2016), 10.1038/ncomms12998] with a complete model where longitudinal components of the electric field are taken into account. Our model matches the experimental data and excludes by 11 standard deviations the approximation of a complete transverse field. This demonstrates the relevance of all field components for the interaction of twisted light with matter.

  13. Plasmonic Light Scattering in Textured Silicon Solar Cells with Indium Nanoparticles from Normal to Non-Normal Light Incidence

    Directory of Open Access Journals (Sweden)

    Wen-Jeng Ho

    2017-07-01

    Full Text Available In this study, we sought to improve the light trapping of textured silicon solar cells using the plasmonic light scattering of indium nanoparticles (In NPs of various dimensions. The light trapping modes of textured-silicon surfaces with and without In NPs were investigated at an angle of incidence (AOI ranging from 0° to 75°. The optical reflectance, external quantum efficiency (EQE, and photovoltaic performance were first characterized under an AOI of 0°. We then compared the EQE and photovoltaic current density-voltage (J-V as a function of AOI in textured silicon solar cells with and without In NPs. We observed a reduction in optical reflectance and an increase in EQE when the cells textured with pyramidal structures were coated with In NPs. We also observed an impressive increase in the average weighted external quantum efficiency (∆EQEw and short-circuit current-density (∆Jsc in cells with In NPs when illuminated under a higher AOI. The ∆EQEw values of cells with In NPs were 0.37% higher than those without In NPs under an AOI of 0°, and 3.48% higher under an AOI of 75°. The ∆Jsc values of cells with In NPs were 0.50% higher than those without In NPs under an AOI of 0°, and 4.57% higher under an AOI of 75°. The application of In NPs clearly improved the light trapping effects. This can be attributed to the effects of plasmonic light-scattering over the entire wavelength range as well as an expanded angle of incident light.

  14. The Light Field Attachment: Turning a DSLR into a Light Field Camera Using a Low Budget Camera Ring

    KAUST Repository

    Wang, Yuwang; Liu, Yebin; Heidrich, Wolfgang; Dai, Qionghai

    2016-01-01

    camera. From an algorithmic point of view, the high-quality light field mode is made possible by a new light field super-resolution method that first improves the spatial resolution and image quality of the side cameras and then interpolates additional

  15. Anti-glare LED lamps with adjustable illumination light field.

    Science.gov (United States)

    Chen, Yung-Sheng; Lin, Chung-Yi; Yeh, Chun-Ming; Kuo, Chie-Tong; Hsu, Chih-Wei; Wang, Hsiang-Chen

    2014-03-10

    We introduce a type of LED light-gauge steel frame lamp with an adjustable illumination light field that does not require a diffusion plate. Base on the Monte Carlo ray tracing method, this lamp has a good glare rating (GR) of 17.5 at 3050 lm. Compared with the traditional LED light-gauge steel frame lamp (without diffusion plate), the new type has low GR. The adjustability of the illumination light field could improve the zebra effect caused by the inadequate illumination light field of the lamp. Meanwhile, we adopt the retinal image analysis to discuss the influence of GR on vision. High GR could reflect stray light on the retinal image, which will reduce vision clarity and hasten the feeling of eye fatigue.

  16. Influence of incident light wavelength on time jitter of fast photomultipliers

    International Nuclear Information System (INIS)

    Moszynski, M.; Vacher, J.

    1977-01-01

    The study of the single photoelectron time resolution as a function of the wavelength of the incident light was performed for a 56 CVP photomultiplier having an S-1 photocathode. The light flash from the XP22 light emitting diode generator was passed through passband filters and illuminated the 5 mm diameter central part of the photocathode. A significant increase of the time resolution above 30% was observed when the wavelength of the incident light was changed from 790 nm to 580 nm. This gives experimental evidence that the time jitter resulting from the spread of the initial velocity of photoelectrons is proportional to the square root of the maximal initial energy of photoelectrons. Based on this conclusion the measured time jitter of C31024, RCA8850 and XP2020 photomultipliers with the use of the XP22 light emitting diode at 560 nm light wavelength was recalculated to estimate the time jitter at 400 nm near the maximum of the photocathode sensitivity. It shows an almost twice larger time spread at 400 nm for the C31024 and RCA8850 with a high gain first dynode and an about 1.5 times larger time spread for the XP2020 photomultiplier, than those measured at 560 nm. (Auth.)

  17. Light distribution analysis of optical fibre probe-based near-field optical tweezers using FDTD

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B H; Yang, L J; Wang, Y [School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Heilongjiang, Harbin, 150001 (China)], E-mail: richelaw@163.com

    2009-09-01

    Optical fibre probe-based near-field optical tweezers overcomes the diffraction limit of conventional optical tweezers, utilizing strong mechanical forces and torque associated with highly enhanced electric fields to trap and manipulate nano-scale particles. Near-field evanescent wave generated at optical fibre probe decays rapidly with the distance that results a significant reduced trapping volume, thus it is necessary to analyze the near-field distribution of optical fibre probe. The finite difference time domain (FDTD) method is applied to characterize the near-field distribution of optical fibre probe. In terms of the distribution patterns, depolarization and polarization, the near-field distributions in longitudinal sections and cross-sections of tapered metal-coated optical fibre probe are calculated. The calculation results reveal that the incident polarized wave becomes depolarized after exiting from the nano-scale aperture of probe. The near-field distribution of the probe is unsymmetrical, and the near-field distribution in the cross-section vertical to the incident polarized wave is different from that in the cross-section parallel to the incident polarized wave. Moreover, the polarization of incident wave has a great impact on the light intensity distribution.

  18. Near-field photometry for organic light-emitting diodes

    Science.gov (United States)

    Li, Rui; Harikumar, Krishnan; Isphording, Alexandar; Venkataramanan, Venkat

    2013-03-01

    Organic Light Emitting Diode (OLED) technology is rapidly maturing to be ready for next generation of light source for general lighting. The current standard test methods for solid state lighting have evolved for semiconductor sources, with point-like emission characteristics. However, OLED devices are extended surface emitters, where spatial uniformity and angular variation of brightness and colour are important. This necessitates advanced test methods to obtain meaningful data for fundamental understanding, lighting product development and deployment. In this work, a near field imaging goniophotometer was used to characterize lighting-class white OLED devices, where luminance and colour information of the pixels on the light sources were measured at a near field distance for various angles. Analysis was performed to obtain angle dependent luminous intensity, CIE chromaticity coordinates and correlated colour temperature (CCT) in the far field. Furthermore, a complete ray set with chromaticity information was generated, so that illuminance at any distance and angle from the light source can be determined. The generated ray set is needed for optical modeling and design of OLED luminaires. Our results show that luminance non-uniformity could potentially affect the luminaire aesthetics and CCT can vary with angle by more than 2000K. This leads to the same source being perceived as warm or cool depending on the viewing angle. As OLEDs are becoming commercially available, this could be a major challenge for lighting designers. Near field measurement can provide detailed specifications and quantitative comparison between OLED products for performance improvement.

  19. Light field reconstruction robust to signal dependent noise

    Science.gov (United States)

    Ren, Kun; Bian, Liheng; Suo, Jinli; Dai, Qionghai

    2014-11-01

    Capturing four dimensional light field data sequentially using a coded aperture camera is an effective approach but suffers from low signal noise ratio. Although multiplexing can help raise the acquisition quality, noise is still a big issue especially for fast acquisition. To address this problem, this paper proposes a noise robust light field reconstruction method. Firstly, scene dependent noise model is studied and incorporated into the light field reconstruction framework. Then, we derive an optimization algorithm for the final reconstruction. We build a prototype by hacking an off-the-shelf camera for data capturing and prove the concept. The effectiveness of this method is validated with experiments on the real captured data.

  20. Light Field Rendering for Head Mounted Displays using Pixel Reprojection

    DEFF Research Database (Denmark)

    Hansen, Anne Juhler; Klein, Jákup; Kraus, Martin

    2017-01-01

    of the information of the different images is redundant, we use pixel reprojection from the corner cameras to compute the remaining images in the light field. We compare the reprojected images with directly rendered images in a user test. In most cases, the users were unable to distinguish the images. In extreme...... cases, the reprojection approach is not capable of creating the light field. We conclude that pixel reprojection is a feasible method for rendering light fields as far as quality of perspective and diffuse shading is concerned, but render time needs to be reduced to make the method practical....

  1. Estimating photosynthetic radiation use efficiency using incident light and photosynthesis of individual leaves.

    Science.gov (United States)

    Rosati, A; Dejong, T M

    2003-06-01

    It has been theorized that photosynthetic radiation use efficiency (PhRUE) over the course of a day is constant for leaves throughout a canopy if leaf nitrogen content and photosynthetic properties are adapted to local light so that canopy photosynthesis over a day is optimized. To test this hypothesis, 'daily' photosynthesis of individual leaves of Solanum melongena plants was calculated from instantaneous rates of photosynthesis integrated over the daylight hours. Instantaneous photosynthesis was estimated from the photosynthetic responses to photosynthetically active radiation (PAR) and from the incident PAR measured on individual leaves during clear and overcast days. Plants were grown with either abundant or scarce N fertilization. Both net and gross daily photosynthesis of leaves were linearly related to daily incident PAR exposure of individual leaves, which implies constant PhRUE over a day throughout the canopy. The slope of these relationships (i.e. PhRUE) increased with N fertilization. When the relationship was calculated for hourly instead of daily periods, the regressions were curvilinear, implying that PhRUE changed with time of the day and incident radiation. Thus, linearity (i.e. constant PhRUE) was achieved only when data were integrated over the entire day. Using average PAR in place of instantaneous incident PAR increased the slope of the relationship between daily photosynthesis and incident PAR of individual leaves, and the regression became curvilinear. The slope of the relationship between daily gross photosynthesis and incident PAR of individual leaves increased for an overcast compared with a clear day, but the slope remained constant for net photosynthesis. This suggests that net PhRUE of all leaves (and thus of the whole canopy) may be constant when integrated over a day, not only when the incident PAR changes with depth in the canopy, but also when it varies on the same leaf owing to changes in daily incident PAR above the canopy. The

  2. New light field camera based on physical based rendering tracing

    Science.gov (United States)

    Chung, Ming-Han; Chang, Shan-Ching; Lee, Chih-Kung

    2014-03-01

    Even though light field technology was first invented more than 50 years ago, it did not gain popularity due to the limitation imposed by the computation technology. With the rapid advancement of computer technology over the last decade, the limitation has been uplifted and the light field technology quickly returns to the spotlight of the research stage. In this paper, PBRT (Physical Based Rendering Tracing) was introduced to overcome the limitation of using traditional optical simulation approach to study the light field camera technology. More specifically, traditional optical simulation approach can only present light energy distribution but typically lack the capability to present the pictures in realistic scenes. By using PBRT, which was developed to create virtual scenes, 4D light field information was obtained to conduct initial data analysis and calculation. This PBRT approach was also used to explore the light field data calculation potential in creating realistic photos. Furthermore, we integrated the optical experimental measurement results with PBRT in order to place the real measurement results into the virtually created scenes. In other words, our approach provided us with a way to establish a link of virtual scene with the real measurement results. Several images developed based on the above-mentioned approaches were analyzed and discussed to verify the pros and cons of the newly developed PBRT based light field camera technology. It will be shown that this newly developed light field camera approach can circumvent the loss of spatial resolution associated with adopting a micro-lens array in front of the image sensors. Detailed operational constraint, performance metrics, computation resources needed, etc. associated with this newly developed light field camera technique were presented in detail.

  3. Metrology and Alignment of Light Weight Grazing Incidence X-Ray Mirrors

    Science.gov (United States)

    Zhang, William; Content, David; Petre, Robert; Saha, Timo

    2000-01-01

    Metrology and alignment of light weight X-ray optics have been a challenge for two reasons: (1) that the intrinsic mirror quality and distortions caused by handling can not be easily separated, and (2) the diffraction limits of the visible light become a severe problem at the order of one arc-minute. Traditional methods of using a normal incident pencil or small parallel beam which monitors a tiny fraction of the mirror in question at a given time can not adequately monitor those distortions. We are developing a normal incidence setup that monitors a large fraction, if not the whole, of the mirror at any given time. It will allow us to align thin X-ray mirrors to-an accuracy of a few arc seconds or to a limit dominated by the mirror intrinsic quality.

  4. Investigation and modeling of the effects of light spectrum and incident angle on the growth of Chlorella vulgaris in photobioreactors.

    Science.gov (United States)

    Souliès, Antoine; Legrand, Jack; Marec, Hélène; Pruvost, Jérémy; Castelain, Cathy; Burghelea, Teodor; Cornet, Jean-François

    2016-03-01

    An in-depth investigation of how various illumination conditions influence microalgal growth in photobioreactors (PBR) has been presented. Effects of both the light emission spectrum (white and red) and the light incident angle (0° and 60°) on the PBR surface were investigated. The experiments were conducted in two fully controlled lab-scale PBRs, a torus PBR and a thin flat-panel PBR for high cell density culture. The results obtained in the torus PBR were used to build the kinetic growth model of Chlorella vulgaris taken as a model species. The PBR model was then applied to the thin flat-panel PBR, which was run with various illumination conditions. Its detailed representation of local rate of photon absorption under various conditions (spectral calculation of light attenuation, incident angle influence) enabled the model to take into account all the tested conditions with no further adjustment. This allowed a detailed investigation of the coupling between radiation field and photosynthetic growth. Effects of all the radiation conditions together with pigment acclimation, which was found to be relevant, were investigated in depth. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:247-261, 2016. © 2016 American Institute of Chemical Engineers.

  5. Light trapping for emission from a photovoltaic cell under normally incident monochromatic illumination

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Iizuka, Hideo; Mizuno, Shintaro; Hasegawa, Kazuo; Ichikawa, Tadashi; Ito, Hiroshi; Kajino, Tsutomu [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Ichiki, Akihisa; Motohiro, Tomoyoshi [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

    2014-09-28

    We have theoretically demonstrated a new light-trapping mechanism to reduce emission from a photovoltaic (PV) cell used for a monochromatic light source, which improves limiting conversion efficiency determined by the detailed balance. A multilayered bandpass filter formed on the surface of a PV cell has been found to prevent the light generated inside by radiative recombination from escaping the cell, resulting in a remarkable decrease of the effective solid angle for the emission. We have clarified a guide to design a suitable configuration of the bandpass filter and achieved significant reduction of the emission. The resultant gain in monochromatic conversion efficiency in the radiative limit due to the optimally designed 18-layerd bandpass filters is as high as 6% under normally incident 1064 nm illumination of 10 mW/cm²~ 1 kW/cm², compared with the efficiency for the perfect anti-reflection treatment to the surface of a conventional solar cell.

  6. The Light Field Attachment: Turning a DSLR into a Light Field Camera Using a Low Budget Camera Ring

    KAUST Repository

    Wang, Yuwang

    2016-11-16

    We propose a concept for a lens attachment that turns a standard DSLR camera and lens into a light field camera. The attachment consists of 8 low-resolution, low-quality side cameras arranged around the central high-quality SLR lens. Unlike most existing light field camera architectures, this design provides a high-quality 2D image mode, while simultaneously enabling a new high-quality light field mode with a large camera baseline but little added weight, cost, or bulk compared with the base DSLR camera. From an algorithmic point of view, the high-quality light field mode is made possible by a new light field super-resolution method that first improves the spatial resolution and image quality of the side cameras and then interpolates additional views as needed. At the heart of this process is a super-resolution method that we call iterative Patch- And Depth-based Synthesis (iPADS), which combines patch-based and depth-based synthesis in a novel fashion. Experimental results obtained for both real captured data and synthetic data confirm that our method achieves substantial improvements in super-resolution for side-view images as well as the high-quality and view-coherent rendering of dense and high-resolution light fields.

  7. Influence of local field on spontaneous light emission by nanoparticles

    DEFF Research Database (Denmark)

    Keller, Ole; Lozovski, V.; Iezhokin, I.

    2009-01-01

    moment of transition that takes local-field effects into account. The effective dipole moment depends on the particle shape and size. Therefore, dipole radiation depends on those parameters too. The direction patterns of light emission by cubic particles have been calculated. The particles have been......A self-consistent approach based on the local-field concept has been proposed to calculate the direction patterns of light emission by nanoparticles with various shapes. The main idea of the method consists in constructing self-consistent equations for the electromagnetic field at any point...... of the system. The solution of the equations brings about relationships between the local field at an arbitrary point in the system and the external long-wave field via the local-field factor. The latter connects the initial moment of optical dipole transition per system volume unit and the effective dipole...

  8. Light cone sum rules in nonabelian gauge field theory

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, S [Bern Univ. (Switzerland). Inst. fuer Theoretische Physik

    1981-03-24

    The author examines, in the context of nonabelian gauge field theory, the derivation of the light cone sum rules which were obtained earlier on the assumption of dominance of canonical singularity in the current commutator on the light cone. The retarded scaling functions appearing in the sum rules are numbers known in terms of the charges of the quarks and the number of quarks and gluons in the theory. Possible applications of the sum rules are suggested.

  9. 3D reconstruction based on light field images

    Science.gov (United States)

    Zhu, Dong; Wu, Chunhong; Liu, Yunluo; Fu, Dongmei

    2018-04-01

    This paper proposed a method of reconstructing three-dimensional (3D) scene from two light field images capture by Lytro illium. The work was carried out by first extracting the sub-aperture images from light field images and using the scale-invariant feature transform (SIFT) for feature registration on the selected sub-aperture images. Structure from motion (SFM) algorithm is further used on the registration completed sub-aperture images to reconstruct the three-dimensional scene. 3D sparse point cloud was obtained in the end. The method shows that the 3D reconstruction can be implemented by only two light field camera captures, rather than at least a dozen times captures by traditional cameras. This can effectively solve the time-consuming, laborious issues for 3D reconstruction based on traditional digital cameras, to achieve a more rapid, convenient and accurate reconstruction.

  10. Light-front field theory in the description of hadrons

    Science.gov (United States)

    Ji, Chueng-Ryong

    2017-03-01

    We discuss the use of light-front field theory in the descriptions of hadrons. In particular, we clarify the confusion in the prevailing notion of the equivalence between the infinite momentum frame and the light-front dynamics and the advantage of the light-front dynamics in hadron physics. As an application, we present our recent work on the flavor asymmetry in the proton sea and identify the presence of the delta-function contributions associated with end-point singularities arising from the chiral effective theory calculation. The results pave the way for phenomenological applications of pion cloud models that are manifestly consistent with the chiral symmetry properties of QCD.

  11. Stray light field dependence for large astronomical space telescopes

    Science.gov (United States)

    Lightsey, Paul A.; Bowers, Charles W.

    2017-09-01

    aspect ratio of the tubular baffle length to PM diameter. Additional analysis has been done to examine the stray light implications for the fields near the image of a bright source. This near field stray light is shown to be dependent on the Bidirectional Reflectance Distribution Function (BRDF) characteristics of the mirrors in the optical train. The near field stray light contribution is dominated by those mirrors closer to the focal plane compared to the contributions from the PM and SM. Hence the near field stray light is independent of the exterior telescope baffle geometry. Contributions from self-emission from the telescope have been compared to natural background for telescopes operating at infrared wavelengths.

  12. Real-time Image Generation for Compressive Light Field Displays

    International Nuclear Information System (INIS)

    Wetzstein, G; Lanman, D; Hirsch, M; Raskar, R

    2013-01-01

    With the invention of integral imaging and parallax barriers in the beginning of the 20th century, glasses-free 3D displays have become feasible. Only today—more than a century later—glasses-free 3D displays are finally emerging in the consumer market. The technologies being employed in current-generation devices, however, are fundamentally the same as what was invented 100 years ago. With rapid advances in optical fabrication, digital processing power, and computational perception, a new generation of display technology is emerging: compressive displays exploring the co-design of optical elements and computational processing while taking particular characteristics of the human visual system into account. In this paper, we discuss real-time implementation strategies for emerging compressive light field displays. We consider displays composed of multiple stacked layers of light-attenuating or polarization-rotating layers, such as LCDs. The involved image generation requires iterative tomographic image synthesis. We demonstrate that, for the case of light field display, computed tomographic light field synthesis maps well to operations included in the standard graphics pipeline, facilitating efficient GPU-based implementations with real-time framerates.

  13. Light pressure of time-dependent fields in plasmas

    International Nuclear Information System (INIS)

    Zeidler, A.; Schnabl, H.; Mulser, P.

    1985-01-01

    An expression of the light pressure Pi is derived for the case of a nearly monochromatic electromagnetic wave with arbitrarily time-dependent amplitude. Thereby Pi is defined as the time-averaged force density exerted on a plasma by the wave. The resulting equations are valid for both transverse and longitudinal waves. The light pressure turns out to consist of two components: the well-known gradient-type term and a new nonstationary solenoidal term. This is true for warm as well as cold plasmas. The importance of the new term for the generation of static magnetic fields is shown, and a model in which shear forces may result is given. Formulas for the nonstationary light pressure developed previously are discussed

  14. Light-front field theory in the description of hadrons

    Directory of Open Access Journals (Sweden)

    Ji Chueng-Ryong

    2017-01-01

    Full Text Available We discuss the use of light-front field theory in the descriptions of hadrons. In particular, we clarify the confusion in the prevailing notion of the equivalence between the infinite momentum frame and the light-front dynamics and the advantage of the light-front dynamics in hadron physics. As an application, we present our recent work on the flavor asymmetry in the proton sea and identify the presence of the delta-function contributions associated with end-point singularities arising from the chiral effective theory calculation. The results pave the way for phenomenological applications of pion cloud models that are manifestly consistent with the chiral symmetry properties of QCD.

  15. Intracluster light at the Frontier - II. The Frontier Fields Clusters

    Science.gov (United States)

    Montes, Mireia; Trujillo, Ignacio

    2018-02-01

    Multiwavelength deep observations are a key tool to understand the origin of the diffuse light in clusters of galaxies: the intracluster light (ICL). For this reason, we take advantage of the Hubble Frontier Fields (HFF) survey to investigate the properties of the stellar populations of the ICL of its six massive intermediate redshift (0.3 1015 M⊙) clusters is formed by the stripping of MW-like objects that have been accreted at z < 1, in agreement with current simulations. We do not find any significant increase in the fraction of light of the ICL with cosmic time, although the redshift range explored is narrow to derive any strong conclusion. When exploring the slope of the stellar mass density profile, we found that the ICL of the HFF clusters follows the shape of their underlying dark matter haloes, in agreement with the idea that the ICL is the result of the stripping of galaxies at recent times.

  16. Controlling optical properties of periodic gold nanoparticle arrays by changing the substrate, topologic shapes of nanoparticles, and polarization direction of incident light

    International Nuclear Information System (INIS)

    Ting, Li; Li, Yu; Zhi-Xin, Lu; Gang, Song; Kai, Zhang

    2011-01-01

    The effects of various parameters including thickness and dielectric constants of substrates, shapes of nanoparticles, and polarization direction of incident light, on the extinction spectra of periodic gold nanoparticle arrays are investigated by the full-vectorial three-dimensional (3D) finite difference time domain (FDTD) method. The calculated results show that the substrate affects the extinction spectra by coupling the fields co-excited by the substrate and gold nanoparticles. Extinction spectra are influenced by the shapes of the nanoparticles, but there are no obvious changes in extinction spectra for similar shapes. The polarization direction of incident light has a great influence on the extinction spectra. The implications of these results are discussed. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Control of the electromagnetic drag using fluctuating light fields

    Science.gov (United States)

    Pastor, Víctor J. López; Marqués, Manuel I.

    2018-05-01

    An expression for the electromagnetic drag force experienced by an electric dipole in a light field consisting of a monochromatic plane wave with polarization and phase randomly fluctuating is obtained. The expression explicitly considers the transformations of the field and frequency due to the Doppler shift and the change of the polarizability response of the electric dipole. The conditions to be fulfilled by the polarizability of the dipole in order to obtain a positive, a null, and a negative drag coefficient are analytically determined and checked against numerical simulations for the dynamics of a silver nanoparticle. The theoretically predicted diffusive, superdiffusive, and exponentially accelerated dynamical regimes are numerically confirmed.

  18. Higgs mechanism in light-front quantized field theory

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, P P

    1993-12-31

    The spontaneous symmetry breaking of continuous symmetry in light-front quantized scalar field theory is studied following the standard Dirac procedure for constrained dynamical systems. A non-local constraint is found to follow. The values of the constant backgrounds fields (zero modes) at the tree level, as a consequence, are shown to given by minimizing the light-front energy. The zero modes are shown to commute with the non-zero ones and the isovector built from them is seen to characterize a (non-perturbative) vacuum state and the corresponding physical sector. The infinite degeneracy of the vacuum is described by the continuum of the allowed orientations of this background isovector in the isospin space. The symmetry generators in the quantized field theory annihilate the vacuum is contrast to the case of equal-time quantization. Not all of them are conserved and the conserved ones determine the surviving symmetry of the quantum theory Lagrangian. The criteria for determining the background isovector and the counting of the number of Goldstone bosons goes as in the equal-time case. A demonstration in favour of the absence of Goldstone bosons in two dimensions is also found. Finally, is extended to an understanding of the Higgs mechanism in light-front frame. (author). 13 refs.

  19. Improved depth estimation with the light field camera

    Science.gov (United States)

    Wang, Huachun; Sang, Xinzhu; Chen, Duo; Guo, Nan; Wang, Peng; Yu, Xunbo; Yan, Binbin; Wang, Kuiru; Yu, Chongxiu

    2017-10-01

    Light-field cameras are used in consumer and industrial applications. An array of micro-lenses captures enough information that one can refocus images after acquisition, as well as shift one's viewpoint within the sub-apertures of the main lens, effectively obtaining multiple views. Thus, depth estimation from both defocus and correspondence are now available in a single capture. And Lytro.Inc also provides a depth estimation from a single-shot capture with light field camera, like Lytro Illum. This Lytro depth estimation containing many correct depth information can be used for higher quality estimation. In this paper, we present a novel simple and principled algorithm that computes dense depth estimation by combining defocus, correspondence and Lytro depth estimations. We analyze 2D epipolar image (EPI) to get defocus and correspondence depth maps. Defocus depth is obtained by computing the spatial gradient after angular integration and correspondence depth by computing the angular variance from EPIs. Lytro depth can be extracted from Lyrto Illum with software. We then show how to combine the three cues into a high quality depth map. Our method for depth estimation is suitable for computer vision applications such as matting, full control of depth-of-field, and surface reconstruction, as well as light filed display

  20. Higgs mechanism in light-front quantized field theory

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1992-01-01

    The spontaneous symmetry breaking of continuous symmetry in light-front quantized scalar field theory is studied following the standard Dirac procedure for constrained dynamical systems. A non-local constraint is found to follow. The values of the constant backgrounds fields (zero modes) at the tree level, as a consequence, are shown to given by minimizing the light-front energy. The zero modes are shown to commute with the non-zero ones and the isovector built from them is seen to characterize a (non-perturbative) vacuum state and the corresponding physical sector. The infinite degeneracy of the vacuum is described by the continuum of the allowed orientations of this background isovector in the isospin space. The symmetry generators in the quantized field theory annihilate the vacuum is contrast to the case of equal-time quantization. Not all of them are conserved and the conserved ones determine the surviving symmetry of the quantum theory Lagrangian. The criteria for determining the background isovector and the counting of the number of Goldstone bosons goes as in the equal-time case. A demonstration in favour of the absence of Goldstone bosons in two dimensions is also found. Finally, is extended to an understanding of the Higgs mechanism in light-front frame. (author). 13 refs

  1. Depth estimation of complex geometry scenes from light fields

    Science.gov (United States)

    Si, Lipeng; Wang, Qing

    2018-01-01

    The surface camera (SCam) of light fields gathers angular sample rays passing through a 3D point. The consistency of SCams is evaluated to estimate the depth map of scene. But the consistency is affected by several limitations such as occlusions or non-Lambertian surfaces. To solve those limitations, the SCam is partitioned into two segments that one of them could satisfy the consistency constraint. The segmentation pattern of SCam is highly related to the texture of spatial patch, so we enforce a mask matching to describe the shape correlation between segments of SCam and spatial patch. To further address the ambiguity in textureless region, a global method with pixel-wise plane label is presented. Plane label inference at each pixel can recover not only depth value but also local geometry structure, that is suitable for light fields with sub-pixel disparities and continuous view variation. Our method is evaluated on public light field datasets and outperforms the state-of-the-art.

  2. A comparison of the quality of image acquisition between the incident dark field and sidestream dark field video-microscopes

    NARCIS (Netherlands)

    E. Gilbert-Kawai; J. Coppel (Jonny); V. Bountziouka (Vassiliki); C. Ince (Can); D. Martin (Daniel)

    2016-01-01

    markdownabstract__Background__ The ‘Cytocam’ is a third generation video-microscope, which enables real time visualisation of the in vivo microcirculation. Based upon the principle of incident dark field (IDF) illumination, this hand held computer-controlled device was designed to address the

  3. A comparison of the quality of image acquisition between the incident dark field and sidestream dark field video-microscopes

    NARCIS (Netherlands)

    Gilbert-Kawai, Edward; Coppel, Jonny; Bountziouka, Vassiliki; Ince, Can; Martin, Daniel; Ahuja, V.; Aref-Adib, G.; Burnham, R.; Chisholm, A.; Clarke, K.; Coates, D.; Coates, M.; Cook, D.; Cox, M.; Dhillon, S.; Dougall, C.; Doyle, P.; Duncan, P.; Edsell, M.; Edwards, L.; Evans, L.; Gardiner, P.; Grocott, M.; Gunning, P.; Hart, N.; Harrington, J.; Harvey, J.; Holloway, C.; Howard, D.; Hurlbut, D.; Imray, C.; Jonas, M.; van der Kaaij, J.; Khosravi, M.; Kolfschoten, N.; Levett, D.; Luery, H.; Luks, A.; Martin, D.; McMorrow, R.; Meale, P.; Mitchell, K.; Montgomery, H.; Morgan, G.; Morgan, J.; Murray, A.; Mythen, M.; Newman, S.; O'Dwyer, M.; Pate, J.

    2016-01-01

    Background: The 'Cytocam' is a third generation video-microscope, which enables real time visualisation of the in vivo microcirculation. Based upon the principle of incident dark field (IDF) illumination, this hand held computer-controlled device was designed to address the technical limitations of

  4. Linux malware incident response an excerpt from malware forensic field guide for Linux systems

    CERN Document Server

    Malin, Cameron H; Aquilina, James M

    2013-01-01

    Linux Malware Incident Response is a ""first look"" at the Malware Forensics Field Guide for Linux Systems, exhibiting the first steps in investigating Linux-based incidents. The Syngress Digital Forensics Field Guides series includes companions for any digital and computer forensic investigator and analyst. Each book is a ""toolkit"" with checklists for specific tasks, case studies of difficult situations, and expert analyst tips. This compendium of tools for computer forensics analysts and investigators is presented in a succinct outline format with cross-references to suppleme

  5. Light depolarization induced by metallic tips in apertureless near-field optical microscopy and tip-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gucciardi, P G [CNR-Istituto per i Processi Chimico-Fisici, sezione Messina, Salita Sperone, Contrada Papardo, I-98158 Faro Superiore, Messina (Italy); Lopes, M; Deturche, R; Julien, C; Barchiesi, D; Chapelle, M Lamy de la [Institut Charles Delaunay-CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de Technologie de Troyes, 12 rue Marie Curie, BP2060, 10010 Troyes (France)

    2008-05-28

    We have investigated the depolarization effects of light scattered by sharp tips used for apertureless near-field optical microscopy. Dielectric and metal coated tips have been investigated and depolarization factors between 5 and 30% have been measured, changing as a function of the incident light polarization and of the tip shape. The experimental results are in good agreement with theoretical calculations performed by the finite element method, giving a near-field depolarization factor close to 10%. The effect of depolarization has been investigated in polarized tip-enhanced Raman spectroscopy (TERS) experiments; the depolarization gives rise to forbidden Raman modes in Si crystals.

  6. Sky light polarization detection with linear polarizer triplet in light field camera inspired by insect vision.

    Science.gov (United States)

    Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Liu, Zejin

    2015-10-20

    Stable information of a sky light polarization pattern can be used for navigation with various advantages such as better performance of anti-interference, no "error cumulative effect," and so on. But the existing method of sky light polarization measurement is weak in real-time performance or with a complex system. Inspired by the navigational capability of a Cataglyphis with its compound eyes, we introduce a new approach to acquire the all-sky image under different polarization directions with one camera and without a rotating polarizer, so as to detect the polarization pattern across the full sky in a single snapshot. Our system is based on a handheld light field camera with a wide-angle lens and a triplet linear polarizer placed over its aperture stop. Experimental results agree with the theoretical predictions. Not only real-time detection but simple and costless architecture demonstrates the superiority of the approach proposed in this paper.

  7. Spin light of neutrino in matter and electromagnetic fields

    International Nuclear Information System (INIS)

    Lobanov, A.; Studenikin, A.

    2003-01-01

    A new type of electromagnetic radiation by a neutrino with non-zero magnetic (and/or electric) moment moving in background matter and electromagnetic field is considered. This radiation originates from the quantum spin flip transitions and we have named it as 'spin light of neutrino' (SLν). The neutrino initially unpolarized beam (equal mixture of ν L and ν R ) can be converted to the totally polarized beam composed of only ν R by the neutrino spin light in matter and electromagnetic fields. The quasi-classical theory of this radiation is developed on the basis of the generalized Bargmann-Michel-Telegdi equation. The considered radiation is important for environments with high effective densities, n, because the total radiation power is proportional to n 4 . The spin light of neutrino, in contrast to the Cherenkov or transition radiation of neutrino in matter, does not vanish in the case of the refractive index of matter is equal to unit. The specific features of this new radiation are: (i) the total power of the radiation is proportional to γ 4 , and (ii) the radiation is beamed within a small angle δθ∼γ -1 , where γ is the neutrino Lorentz factor. Applications of this new type of neutrino radiation to astrophysics, in particular to gamma-ray bursts, and the early universe should be important

  8. Spatial and Angular Resolution Enhancement of Light Fields Using Convolutional Neural Networks

    Science.gov (United States)

    Gul, M. Shahzeb Khan; Gunturk, Bahadir K.

    2018-05-01

    Light field imaging extends the traditional photography by capturing both spatial and angular distribution of light, which enables new capabilities, including post-capture refocusing, post-capture aperture control, and depth estimation from a single shot. Micro-lens array (MLA) based light field cameras offer a cost-effective approach to capture light field. A major drawback of MLA based light field cameras is low spatial resolution, which is due to the fact that a single image sensor is shared to capture both spatial and angular information. In this paper, we present a learning based light field enhancement approach. Both spatial and angular resolution of captured light field is enhanced using convolutional neural networks. The proposed method is tested with real light field data captured with a Lytro light field camera, clearly demonstrating spatial and angular resolution improvement.

  9. Laser speckle contrast imaging using light field microscope approach

    Science.gov (United States)

    Ma, Xiaohui; Wang, Anting; Ma, Fenghua; Wang, Zi; Ming, Hai

    2018-01-01

    In this paper, a laser speckle contrast imaging (LSCI) system using light field (LF) microscope approach is proposed. As far as we known, it is first time to combine LSCI with LF. To verify this idea, a prototype consists of a modified LF microscope imaging system and an experimental device was built. A commercially used Lytro camera was modified for microscope imaging. Hollow glass tubes with different depth fixed in glass dish were used to simulate the vessels in brain and test the performance of the system. Compared with conventional LSCI, three new functions can be realized by using our system, which include refocusing, extending the depth of field (DOF) and gathering 3D information. Experiments show that the principle is feasible and the proposed system works well.

  10. Free-Free Transitions in the Presence of Laser Fields at Very Low Incident Electron Energy

    Science.gov (United States)

    Bhatia, A. K.; Sinha, Chandana

    2010-01-01

    We study the free-free transition in electron-hydrogenic systems in ground state in presence of an external laser field at very loud incident energies. The laser field is treated classically while the collision dynamics is treated quantum mechanically. The laser field is chosen to be monochromatic, linearly polarized and homogeneous. The incident electron is considered to be dressed by the laser in a nonperturbative manner by choosing a Volkov wave function for it. The scattering weave function for the electron is solved numerically by taking into account the effect of the electron exchange, short-range as well as of the long-range interactions to get the S and P wave phase shifts while for the higher angular momentum phase shifts the exchange approximation has only been considered. We calculate the laser assisted differential cross sections (LADCS) for the aforesaid free-free transition process for single photon absorption/emission. The laser intensity is chosen to be much less than the atomic field intensity. A strong suppression is noted in the LADCS as compared to the field free (FF) cross sections. Unlike the FF ones, the LADCS exhibit some oscillations having a distinct maximum at a low value of the scattering angle depending on the laser parameters as well as on the incident energies.

  11. Robust sky light polarization detection with an S-wave plate in a light field camera.

    Science.gov (United States)

    Zhang, Wenjing; Zhang, Xuanzhe; Cao, Yu; Liu, Haibo; Liu, Zejin

    2016-05-01

    The sky light polarization navigator has many advantages, such as low cost, no decrease in accuracy with continuous operation, etc. However, current celestial polarization measurement methods often suffer from low performance when the sky is covered by clouds, which reduce the accuracy of navigation. In this paper we introduce a new method and structure based on a handheld light field camera and a radial polarizer, composed of an S-wave plate and a linear polarizer, to detect the sky light polarization pattern across a wide field of view in a single snapshot. Each micro-subimage has a special intensity distribution. After extracting the texture feature of these subimages, stable distribution information of the angle of polarization under a cloudy sky can be obtained. Our experimental results match well with the predicted properties of the theory. Because the polarization pattern is obtained through image processing, rather than traditional methods based on mathematical computation, this method is less sensitive to errors of pixel gray value and thus has better anti-interference performance.

  12. Influence of pump-field scattering on nonclassical-light generation in a photonic-band-gap nonlinear planar waveguide

    International Nuclear Information System (INIS)

    Perina, Jan Jr.; Sibilia, Concita; Tricca, Daniela; Bertolotti, Mario

    2005-01-01

    Optical parametric process occurring in a nonlinear planar waveguide can serve as a source of light with nonclassical properties. The properties of the generated fields are substantially modified by scattering of the nonlinearly interacting fields in a photonic-band-gap structure inside the waveguide. A general quantum model of linear operator amplitude corrections to the amplitude mean values and its numerical analysis provide conditions for efficient squeezed-light generation as well as generation of light with sub-Poissonian photon-number statistics. The destructive influence of phase mismatch of the nonlinear interaction can fully be compensated using a suitable photonic-band-gap structure inside the waveguide. Also an increase of the signal-to-noise ratio of the incident optical field can be reached in the waveguide

  13. Management of In-Field Patient Tracking and Triage by Using Near-Field Communication in Mass Casualty Incidents.

    Science.gov (United States)

    Cheng, Po-Liang; Su, Yung-Cheng; Hou, Chung-Hung; Chang, Po-Lun

    2017-01-01

    Near field communications (NFC) is an emerging technology that may potentialy assist with disaster management. A smartphone-based app was designed to help track patient flow in real time. A table-drill was held as a brief evaluation and it showed significant imporvement in both efficacy and accuracy of patient management. It is feasible to use NFC-embedded smartphones to clarify the ambiguous and chaotic patient flow in a mass casualty incident.

  14. Magnetic field effect in organic light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Niedermeier, Ulrich

    2009-12-14

    The discovery of a magnetic field dependent resistance change of organic light emitting diodes (OLEDs) in the year 2003 has attracted considerable scientific and industrial research interest. However, despite previous progress in the field of organic spin-electronics, the phenomenon of the ''organic magnetoresistance (OMR) effect'' is not yet completely understood. In order to improve the understanding of the microscopic mechanisms which ultimately cause the OMR effect, experimental investigations as well as theoretical considerations concerning the OMR are addressed in this thesis. In polymer-based OLED devices the functional dependencies of the OMR effect on relevant parameters like magnetic field, operating voltage, operating current and temperature are investigated. Based on these results, previously published models for potential OMR mechanisms are critically analyzed and evaluated. Finally, a concept for the OMR effect is favored which suggests magnetic field dependent changes of the spin state of electron-hole pairs as being responsible for changes in current flow and light emission in OLEDs. In the framework of this concept it is possible to explain all results from own measurements as well as results from literature. Another important finding made in this thesis is the fact that the value of the OMR signal in the investigated OLED devices can be enhanced by appropriate electrical and optical conditioning processes. In particular, electrical conditioning causes a significant enhancement of the OMR values, while at the same time it has a negative effect on charge carrier transport and optical device characteristics. These results can be explained by additional results from charge carrier extraction measurements which suggest that electrical conditioning leads to an increase in the number of electronic trap states inside the emission layer of the investigated OLED devices. The positive influence of trap states on the OMR effect is

  15. Light field moment imaging with the ptychographic iterative engine

    Directory of Open Access Journals (Sweden)

    Zhilong Jiang

    2014-10-01

    Full Text Available The recently developed Light Field Moment Imaging (LMI is adopted to show the stereoscopic structure of the sample studied in Coherent Diffractive Imaging (CDI, where 3D image were always generated with complicated experimental procedure such as the rotation of the sample and time-consuming computation. The animation of large view angle can be generated with LMI very quickly, and the 3D structure of sample can be shown vividly. This method can find many applications for the coherent diffraction imaging with x-ray and electron beams, where a glimpse of the hierarchical structure required and the quick and simple 3D view of object is sufficient. The feasibility of this method is demonstrated theoretically and experimentally with a recently developed CDI method called Ptychographic Iterative Engine.

  16. Optical Implementation of Non-locality with Coherent Light Fields for Quantum Communication

    OpenAIRE

    Lee, Kim Fook

    2008-01-01

    Polarization correlations of two distant observers are observed by using coherent light fields based on Stapp's formulation of nonlocality. Using a 50/50 beam splitter transformation, a vertically polarized coherent light field is found to be entangled with a horizontally polarized coherent noise field. The superposed light fields at each output port of the beam splitter are sent to two distant observers, where the fields are interfered and manipulated at each observer by using a quarter wave...

  17. Thermal inflation with a thermal waterfall scalar field coupled to a light spectator scalar field

    Science.gov (United States)

    Dimopoulos, Konstantinos; Lyth, David H.; Rumsey, Arron

    2017-05-01

    A new model of thermal inflation is introduced, in which the mass of the thermal waterfall field is dependent on a light spectator scalar field. Using the δ N formalism, the "end of inflation" scenario is investigated in order to ascertain whether this model is able to produce the dominant contribution to the primordial curvature perturbation. A multitude of constraints are considered so as to explore the parameter space, with particular emphasis on key observational signatures. For natural values of the parameters, the model is found to yield a sharp prediction for the scalar spectral index and its running, well within the current observational bounds.

  18. Evaluation of Alternative Field Buses for Lighting ControlApplications

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Ed; Rubinstein, Francis

    2005-03-21

    The Subcontract Statement of Work consists of two major tasks. This report is the Final Report in fulfillment of the contract deliverable for Task 1. The purpose of Task 1 was to evaluate existing and emerging protocols and standards for interfacing sensors and controllers for communicating with integrated lighting control systems in commercial buildings. The detailed task description follows: Task 1. Evaluate alternative sensor/field buses. The objective of this task is to evaluate existing and emerging standards for interfacing sensors and controllers for communicating with integrated lighting control systems in commercial buildings. The protocols to be evaluated will include at least: (1) 1-Wire Net, (2) DALI, (3) MODBUS (or appropriate substitute such as EIB) and (4) ZigBee. The evaluation will include a comparative matrix for comparing the technical performance features of the different alternative systems. The performance features to be considered include: (1) directionality and network speed, (2) error control, (3) latency times, (4) allowable cable voltage drop, (5) topology, and (6) polarization. Specifically, Subcontractor will: (1) Analyze the proposed network architecture and identify potential problems that may require further research and specification. (2) Help identify and specify additional software and hardware components that may be required for the communications network to operate properly. (3) Identify areas of the architecture that can benefit from existing standards and technology and enumerate those standards and technologies. (4) Identify existing companies that may have relevant technology that can be applied to this research. (5) Help determine if new standards or technologies need to be developed.

  19. Parameterized source term in the diffusion approximation for enhanced near-field modeling of collimated light

    Science.gov (United States)

    Jia, Mengyu; Wang, Shuang; Chen, Xueying; Gao, Feng; Zhao, Huijuan

    2016-03-01

    Most analytical methods for describing light propagation in turbid medium exhibit low effectiveness in the near-field of a collimated source. Motivated by the Charge Simulation Method in electromagnetic theory as well as the established discrete source based modeling, we have reported on an improved explicit model, referred to as "Virtual Source" (VS) diffuse approximation (DA), to inherit the mathematical simplicity of the DA while considerably extend its validity in modeling the near-field photon migration in low-albedo medium. In this model, the collimated light in the standard DA is analogously approximated as multiple isotropic point sources (VS) distributed along the incident direction. For performance enhancement, a fitting procedure between the calculated and realistic reflectances is adopted in the nearfield to optimize the VS parameters (intensities and locations). To be practically applicable, an explicit 2VS-DA model is established based on close-form derivations of the VS parameters for the typical ranges of the optical parameters. The proposed VS-DA model is validated by comparing with the Monte Carlo simulations, and further introduced in the image reconstruction of the Laminar Optical Tomography system.

  20. Self-consistent Optomechanical Dynamics and Radiation Forces in Thermal Light Fields

    International Nuclear Information System (INIS)

    Sonnleitner, M.

    2014-01-01

    We discuss two different aspects of the mechanical interaction between neutral matter and electromagnetic radiation.The first part addresses the complex dynamics of an elastic dielectric deformed by optical forces. To do so we use a one-dimensional model describing the medium by an array of beam splitters such that the interaction with the incident waves can be described with a transfer-matrix approach. Since the force on each individual beam splitter is known we thus obtain the correct volumetric force density inside the medium. Sending a light field through an initially homogeneous dielectric then results in density modulations which in turn alter the optical properties of this medium.The second part is concerned with mechanical light-effects on atoms in thermal radiation fields. At hand of a generic setup of an atom interacting with a hot sphere emitting blackbody radiation we show that the emerging gradient force may surpass gravity by several orders of magnitude. The strength of the repulsive scattering force strongly depends on the spectrum of the involved atoms and can be neglected in some setups. A special emphasis lies on possible implications on astrophysical scenarios where the interactions between heated dust and atoms, molecules or nanoparticles are of crucial interest. (author) [de

  1. Concept of dual-resolution light field imaging using an organic photoelectric conversion film for high-resolution light field photography.

    Science.gov (United States)

    Sugimura, Daisuke; Kobayashi, Suguru; Hamamoto, Takayuki

    2017-11-01

    Light field imaging is an emerging technique that is employed to realize various applications such as multi-viewpoint imaging, focal-point changing, and depth estimation. In this paper, we propose a concept of a dual-resolution light field imaging system to synthesize super-resolved multi-viewpoint images. The key novelty of this study is the use of an organic photoelectric conversion film (OPCF), which is a device that converts spectra information of incoming light within a certain wavelength range into an electrical signal (pixel value), for light field imaging. In our imaging system, we place the OPCF having the green spectral sensitivity onto the micro-lens array of the conventional light field camera. The OPCF allows us to acquire the green spectra information only at the center viewpoint with the full resolution of the image sensor. In contrast, the optical system of the light field camera in our imaging system captures the other spectra information (red and blue) at multiple viewpoints (sub-aperture images) but with low resolution. Thus, our dual-resolution light field imaging system enables us to simultaneously capture information about the target scene at a high spatial resolution as well as the direction information of the incoming light. By exploiting these advantages of our imaging system, our proposed method enables the synthesis of full-resolution multi-viewpoint images. We perform experiments using synthetic images, and the results demonstrate that our method outperforms other previous methods.

  2. Ultraviolet refractometry using field-based light scattering spectroscopy

    Science.gov (United States)

    Fu, Dan; Choi, Wonshik; Sung, Yongjin; Oh, Seungeun; Yaqoob, Zahid; Park, YongKeun; Dasari, Ramachandra R.; Feld, Michael S.

    2010-01-01

    Accurate refractive index measurement in the deep ultraviolet (UV) range is important for the separate quantification of biomolecules such as proteins and DNA in biology. This task is demanding and has not been fully exploited so far. Here we report a new method of measuring refractive index using field-based light scattering spectroscopy, which is applicable to any wavelength range and suitable for both solutions and homogenous objects with well-defined shape such as microspheres. The angular scattering distribution of single microspheres immersed in homogeneous media is measured over the wavelength range 260 to 315 nm using quantitative phase microscopy. By least square fitting the observed scattering distribution with Mie scattering theory, the refractive index of either the sphere or the immersion medium can be determined provided that one is known a priori. Using this method, we have measured the refractive index dispersion of SiO2 spheres and bovine serum albumin (BSA) solutions in the deep UV region. Specific refractive index increments of BSA are also extracted. Typical accuracy of the present refractive index technique is ≤0.003. The precision of refractive index measurements is ≤0.002 and that of specific refractive index increment determination is ≤0.01 mL/g. PMID:20372622

  3. Controlling radiation fields in siemans designed light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Riess, R.; Marchl, T. [Siemens Power Generation Group, Erlangen (Germany)

    1995-03-01

    An essential item for the control of radiation fields is the minimization of the use of satellites in the reactor systems of Light Water Reactors (LWRs). A short description of the qualification of Co-replacement materials will be followed by an illustration of the locations where these materials were implemented in Siemens designed LWRs. Especially experiences in PWRs show the immense influence of reduction of cobalt sources on dose rate buildup. The corrosion and the fatique and wear behavior of the replacement materials has not created concern up to now. A second tool to keep occupational radiation doses at a low level in PWRs is the use of the modified B/Li-chemistry. This is practized in Siemens designed plants by keeping the Li level at a max. value of 2 ppm until it reaches a pH (at 300{degrees}C) of {approximately}7.4. This pH is kept constant until the end of the cycle. The substitution of cobalt base alloys and thus the removal of the Co-59 sources from the system had the largest impact on the radiation levels. Nonetheless, the effectiveness of the coolant chemistry should not be neglected either. Several years of successful operation of PWRs with the replacement materials resulted in an occupational radiation exposure which is below 0.5 man-Sievert/plant and year.

  4. Atomic displacement distributions for light energetic atoms incident on heavy atom targets

    International Nuclear Information System (INIS)

    Brice, D.K.

    1975-01-01

    The depth distributions of atomic displacements produced by 4 to 100 keV H, D, and He ions incident on Cr, Mo, and W targets have been calculated using a sharp displacement threshold, E/sub d/ = 35 eV, and a previously described calculational procedure. These displacement depth distributions have been compared with the depth distributions of energy deposited into atomic processes to determine if a proportionality (modified Kinchin--Pease relationship) can be established. Such a relationship does exist for He ions and D ions incident on these metals at energies above 4 keV and 20 keV, respectively. For H ions the two distributions have significantly different shapes at all incident energies considered

  5. Analysis of recent incidents of on-field violence in sport: legal decisions and additional considerations from psychology.

    Science.gov (United States)

    Kerr, John H

    2009-01-01

    This article focuses on two recent incidents of serious on-field violence in sports and the legal consequences for those involved. The two incidents occurred in Dutch football (soccer) and became infamous owing to the nature of the violent incidents and widespread media coverage. The legal outcomes of these two incidents are described, and some of the difficulties that legal authorities face in considering assaults on the sports field are discussed. A new way of categorizing such violent incidents and the motivation behind them, based on an established psychological theory [reversal theory, Apter, 1982, 2001] is proposed. Taken along with the other points made in this article, being aware of when and how individuals cross the boundaries between play and anger, power or thrill violence may provide an additional perspective to making informed decisions about illegal violent acts on the sports field. Copyright 2008 Wiley-Liss, Inc.

  6. Fourier-transform ghost imaging with pure far-field correlated thermal light

    International Nuclear Information System (INIS)

    Liu Honglin; Shen Xia; Han Shensheng; Zhu Daming

    2007-01-01

    Pure far-field correlated thermal light beams are created with phase grating, and Fourier-transform ghost imaging depending only on the far-field correlation is demonstrated experimentally. Theoretical analysis and the results of experimental investigation of this pure far-field correlated thermal light are presented. Applications which may be exploited with this imaging scheme are discussed

  7. Questions Students Ask: Why Not Bend Light with an Electric Field?

    Science.gov (United States)

    Van Heuvelen, Alan

    1983-01-01

    In response to a question, "Why not use a magnetic or electric field to deflect light?," reviews the relation between electric charge and electric/magnetic fields. Discusses the Faraday effect, (describing matter as an intermediary in the rotation of the place of polarization) and other apparent interactions of light with electric/magnetic fields.…

  8. Laser warning receiver to identify the wavelength and angle of arrival of incident laser light

    Science.gov (United States)

    Sinclair; Michael B.; Sweatt, William C.

    2010-03-23

    A laser warning receiver is disclosed which has up to hundreds of individual optical channels each optically oriented to receive laser light from a different angle of arrival. Each optical channel has an optical wedge to define the angle of arrival, and a lens to focus the laser light onto a multi-wavelength photodetector for that channel. Each multi-wavelength photodetector has a number of semiconductor layers which are located in a multi-dielectric stack that concentrates the laser light into one of the semiconductor layers according to wavelength. An electrical signal from the multi-wavelength photodetector can be processed to determine both the angle of arrival and the wavelength of the laser light.

  9. Exotic behavior of molecules in intense laser light fields. New research directions

    Energy Technology Data Exchange (ETDEWEB)

    Yamanouchi, Kaoru [Tokyo Univ., Department of Chemistry, Tokyo (Japan)

    2002-08-01

    The recent investigation of the dynamical behavior of molecules and clusters in intense laser fields has afforded us invaluable opportunities to understand fundamentals of the interaction between molecular species and light fields as well as to manipulate molecules and their dynamical pathways by taking advantage of characteristics of coherent ultrashort laser light fields. In the present report, new directions of this rapidly growing interdisciplinary research fields called molecular science in intense laser fields are discussed by referring to our recent studies. (author)

  10. The Light-Field of Microbenthic Communities - Radiance Distribution and Microscale Optics of Sandy Coastal Sediments Rid A-1977-2009

    DEFF Research Database (Denmark)

    KUHL, M.; JØRGENSEN, BB

    1994-01-01

    radiance distribution. Comparison of light fields in wet and dry quartz sand showed that the lower refractive index of air than of water caused a more forward-biased scattering in wet sand. Light penetration was therefore deeper and surface irradiance reflectance was lower in wet sand than in dry sand......The light field in coastal sediments was investigated at a spatial resolution of 0.2-0.5 mm by spectral measurements (450-850 nm) of field radiance and scalar irradiance using fiber-optic microprobes. Depth profiles of field radiance were measured with radiance microprobes at representative angles...... relative to vertically incident collimated light in rinsed quartz sand and in a coastal sandy sediment colonized by microalgae. Upwelling and downwelling components of irradiance and scalar irradiance were calculated from the radiance distributions. Calculated total scalar irradiance agreed well...

  11. A "Light Meal" Three Hours Preoperatively Decreases the Incidence of Gastro-Esophageal Reflux in Dogs.

    Science.gov (United States)

    Savvas, Ioannis; Raptopoulos, Dimitrios; Rallis, Timoleon

    Emerging evidence from veterinary and medical clinical research shows that reducing preoperative fasting time may reduce the incidence of gastro-esophageal reflux (GER) intraoperatively. In order to evaluate the effect of two different preoperative fasting times on the incidence of GER during general anesthesia, 120 dogs were randomly assigned to two groups: administration of canned food 3 h before premedication (group C3, n = 60) and administration of canned food 10 h before premedication (group C10, n = 60). The animals were premedicated with propionyl-promazine. Anesthesia was induced with thiopental sodium and maintained with halothane. A pH electrode was introduced into the esophagus, and the esophageal pH was constantly monitored. Esophageal pH of less than 4 or greater than 7.5 was taken as an indication of GER. Three of the 60 dogs of group C3 and 12 of the 60 dogs of group C10 experienced a GER episode, the difference being statistically significant (P = .025). Feeding the dog 3 h before anesthesia at a half daily rate reduces significantly the incidence of GER during anesthesia, compared to the administration of the same amount and type of food 10 h before anesthesia. The administration of a half daily dose of an ordinary canine diet may be useful in clinical practice.

  12. Light Scattering Studies of Organic Field Effect Transistors

    Science.gov (United States)

    Adil, Danish

    Organic semiconductors hold a great promise of enabling new technology based on low cost and flexible electronic devices. While much work has been done in the field of organic semiconductors, the field is still quite immature when compared to that of traditional inorganic based devices. More work is required before the full potential of organic field effect transistors (OFETs), organic light emitting diodes (OLEDs), and organic photovoltaics (OPVs) is realized. Among such work, a further development of diagnostic tools that characterize charge transport and device robustness more efficiently is required. Charge transport in organic semiconductors is limited by the nature of the metal-semiconductor interfaces where charge is injected into the semiconductor film and the semiconductor-dielectric interface where the charge is accumulated and transported. This, combined with that fact that organic semiconductors are especially susceptible to having structural defects induced via oxidation, charge transport induced damage, and metallization results in a situation where a semiconductor film's ability to conduct charge can degrade over time. This degradation manifests itself in the electrical device characteristics of organic based electronic devices. OFETs, for example, may display changes in threshold voltage, lowering of charge carrier mobilities, or a decrease in the On/Off ratio. All these effects sum together to result in degradation in device performance. The work begins with a study where matrix assisted pulsed laser deposition (MAPLE), an alternative organic semiconductor thin film deposition method, is used to fabricate OFETs with improved semiconductor-dielectric interfaces. MAPLE allows for the controlled layer-by-layer growth of the semiconductor film. Devices fabricated using this technique are shown to exhibit desirable characteristics that are otherwise only achievable with additional surface treatments. MAPLE is shown to be viable alternative to other

  13. Laser Light-field Fusion for Wide-field Lensfree On-chip Phase Contrast Microscopy of Nanoparticles

    Science.gov (United States)

    Kazemzadeh, Farnoud; Wong, Alexander

    2016-12-01

    Wide-field lensfree on-chip microscopy, which leverages holography principles to capture interferometric light-field encodings without lenses, is an emerging imaging modality with widespread interest given the large field-of-view compared to lens-based techniques. In this study, we introduce the idea of laser light-field fusion for lensfree on-chip phase contrast microscopy for detecting nanoparticles, where interferometric laser light-field encodings acquired using a lensfree, on-chip setup with laser pulsations at different wavelengths are fused to produce marker-free phase contrast images of particles at the nanometer scale. As a proof of concept, we demonstrate, for the first time, a wide-field lensfree on-chip instrument successfully detecting 300 nm particles across a large field-of-view of ~30 mm2 without any specialized or intricate sample preparation, or the use of synthetic aperture- or shift-based techniques.

  14. Estimation of the light field inside photosynthetic microorganism cultures through Mittag-Leffler functions at depleted light conditions

    Science.gov (United States)

    Fuente, David; Lizama, Carlos; Urchueguía, Javier F.; Conejero, J. Alberto

    2018-01-01

    Light attenuation within suspensions of photosynthetic microorganisms has been widely described by the Lambert-Beer equation. However, at depths where most of the light has been absorbed by the cells, light decay deviates from the exponential behaviour and shows a lower attenuation than the corresponding from the purely exponential fall. This discrepancy can be modelled through the Mittag-Leffler function, extending Lambert-Beer law via a tuning parameter α that takes into account the attenuation process. In this work, we describe a fractional Lambert-Beer law to estimate light attenuation within cultures of model organism Synechocystis sp. PCC 6803. Indeed, we benchmark the measured light field inside cultures of two different Synechocystis strains, namely the wild-type and the antenna mutant strain called Olive at five different cell densities, with our in silico results. The Mittag-Leffler hyper-parameter α that best fits the data is 0.995, close to the exponential case. One of the most striking results to emerge from this work is that unlike prior literature on the subject, this one provides experimental evidence on the validity of fractional calculus for determining the light field. We show that by applying the fractional Lambert-Beer law for describing light attenuation, we are able to properly model light decay in photosynthetic microorganisms suspensions.

  15. Heating nuclei with light ions at GeV incident energies

    International Nuclear Information System (INIS)

    Pollacco, E.C.; Brzychczyk, J.; Volant, C.; Legrain, R.; Nalpas, L.; Bracken, D.S.; Kwiatkowski, K.; Morley, K.B.; Foxford, E.R.; Viola, V.E.; Yoder, N.R.

    1996-03-01

    Hot nuclei are studied, where through an appropriate choice of incident channel and event selection, dynamical effects are attenuated and multifragmentation is limited. Three preparatory results are discussed, the 3 He(1.8 GeV) + nat Ag can be described using and intranuclear cascade, INC, model; through a suitable selection of events a limit of the excitation energy that a nucleus can absorb without breaking into large pieces is given, it is shown, that corresponding alpha decay is consistent with an, evaporative process. (K.A.)

  16. Effect of a microwave field on the cascade arc light emission

    NARCIS (Netherlands)

    Gerasimov, N.T.; Rosado, R.J.; Schram, D.C.

    1977-01-01

    The effect of a pulsed microwave field on the integral light emission from the argon plasma of a DC atmospheric-pressure cascade arc is investigated experimentally. An intensive light pulse and oscillations of light emission at frequencies of the order of 10 kHz are observed. The shape and amplitude

  17. The electronics in fluorescent bulbs and light emitting diodes (LED), rather than ultraviolet radiation, cause increased malignant melanoma incidence in indoor office workers and tanning bed users.

    Science.gov (United States)

    Milham, Samuel; Stetzer, Dave

    2018-07-01

    The epidemiology of cutaneous malignant melanoma (CMM) has a number of facets that do not fit with sunlight and ultraviolet light as the primary etiologic agents. Indoor workers have higher incidence and mortality rates of CMM than outdoor workers; CMM occurs in body locations never exposed to sunlight; CMM incidence is increasing in spite of use of UV blocking agents and small changes in solar radiation. Installation of two new fluorescent lights in the milking parlor holding area of a Minnesota dairy farm in 2015 caused an immediate drop in milk production. This lead to measurement of body amperage in humans exposed to modern non-incandescent lighting. People exposed to old and new fluorescent lights, light emitting diodes (LED) and compact fluorescent lights (CFL) had body amperage levels above those considered carcinogenic. We hypothesize that modern electric lighting is a significant health hazard, a carcinogen, and is causing increasing CMM incidence in indoor office workers and tanning bed users. These lights generate dirty electricity (high frequency voltage transients), radio frequency (RF) radiation, and increase body amperage, all of which have been shown to be carcinogenic. This could explain the failure of ultraviolet blockers to stem the malignant melanoma pandemic. Tanning beds and non-incandescent lighting could be made safe by incorporating a grounded Faraday cage which allows passage of ultraviolet and visible light frequencies and blocks other frequencies. Modern electric lighting should be fabricated to be electrically clean. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Scattered-field FDTD and PSTD algorithms with CPML absorbing boundary conditions for light scattering by aerosols

    International Nuclear Information System (INIS)

    Sun, Wenbo; Videen, Gorden; Fu, Qiang; Hu, Yongxiang

    2013-01-01

    As fundamental parameters for polarized-radiative-transfer calculations, the single-scattering phase matrix of irregularly shaped aerosol particles must be accurately modeled. In this study, a scattered-field finite-difference time-domain (FDTD) model and a scattered-field pseudo-spectral time-domain (PSTD) model are developed for light scattering by arbitrarily shaped dielectric aerosols. The convolutional perfectly matched layer (CPML) absorbing boundary condition (ABC) is used to truncate the computational domain. It is found that the PSTD method is generally more accurate than the FDTD in calculation of the single-scattering properties given similar spatial cell sizes. Since the PSTD can use a coarser grid for large particles, it can lower the memory requirement in the calculation. However, the Fourier transformations in the PSTD need significantly more CPU time than simple subtractions in the FDTD, and the fast Fourier transform requires a power of 2 elements in calculations, thus using the PSTD could not significantly reduce the CPU time required in the numerical modeling. Furthermore, because the scattered-field FDTD/PSTD equations include incident-wave source terms, the FDTD/PSTD model allows for the inclusion of an arbitrarily incident wave source, including a plane parallel wave or a Gaussian beam like those emitted by lasers usually used in laboratory particle characterizations, etc. The scattered-field FDTD and PSTD light-scattering models can be used to calculate single-scattering properties of arbitrarily shaped aerosol particles over broad size and wavelength ranges. -- Highlights: • Scattered-field FDTD and PSTD models are developed for light scattering by aerosols. • Convolutional perfectly matched layer absorbing boundary condition is used. • PSTD is generally more accurate than FDTD in calculating single-scattering properties. • Using same spatial resolution, PSTD requires much larger CPU time than FDTD

  19. Estimating Photosynthetic Radiation Use Efficiency Using Incident Light and Photosynthesis of Individual Leaves

    OpenAIRE

    ROSATI, A.; DEJONG, T. M.

    2003-01-01

    It has been theorized that photosynthetic radiation use efficiency (PhRUE) over the course of a day is constant for leaves throughout a canopy if leaf nitrogen content and photosynthetic properties are adapted to local light so that canopy photosynthesis over a day is optimized. To test this hypothesis, ‘daily’ photosynthesis of individual leaves of Solanum melongena plants was calculated from instantaneous rates of photosynthesis integrated over the daylight hours. Instantaneous photosynthes...

  20. Light-cone AdS/CFT-adapted approach to AdS fields/currents, shadows, and conformal fields

    Energy Technology Data Exchange (ETDEWEB)

    Metsaev, R.R. [Department of Theoretical Physics, P.N. Lebedev Physical Institute, Leninsky prospect 53, Moscow 119991 (Russian Federation)

    2015-10-16

    Light-cone gauge formulation of fields in AdS space and conformal field theory in flat space adapted for the study of AdS/CFT correspondence is developed. Arbitrary spin mixed-symmetry fields in AdS space and arbitrary spin mixed-symmetry currents, shadows, and conformal fields in flat space are considered on an equal footing. For the massless and massive fields in AdS and the conformal fields in flat space, simple light-cone gauge actions leading to decoupled equations of motion are found. For the currents and shadows, simple expressions for all 2-point functions are also found. We demonstrate that representation of conformal algebra generators on space of currents, shadows, and conformal fields can be built in terms of spin operators entering the light-cone gauge formulation of AdS fields. This considerably simplifies the study of AdS/CFT correspondence. Light-cone gauge actions for totally symmetric arbitrary spin long conformal fields in flat space are presented. We apply our approach to the study of totally antisymmetric (one-column) and mixed-symmetry (two-column) fields in AdS space and currents, shadows, and conformal fields in flat space.

  1. Automated and observer based light field indicator edge evaluation in diagnostic X-ray equipment

    OpenAIRE

    Bottaro, Márcio; Nagy, Balázs Vince; Soares, Fernanda Cristina Salvador; Rosendo, Danilo Cabral

    2017-01-01

    Abstract Introduction To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and naïve human observers were asked to mark the light field edge according t...

  2. Three Dimensional Imaging of Cold Atoms in a Magneto Optical Trap with a Light Field Microscope

    Science.gov (United States)

    2017-09-14

    with a Light Field Microscope Gordon E. Lott Follow this and additional works at: https://scholar.afit.edu/etd Part of the Atomic, Molecular and......https://scholar.afit.edu/etd/774 THREE-DIMENSIONAL IMAGING OF COLD ATOMS IN A MAGNETO-OPTICAL TRAP WITH A LIGHT FIELD MICROSCOPE DISSERTATION Gordon E

  3. Diagnosis and incidence risk of clinical canine monocytic ehrlichiosis under field conditions in Southern Europe.

    Science.gov (United States)

    René-Martellet, Magalie; Lebert, Isabelle; Chêne, Jeanne; Massot, Raphaël; Leon, Marta; Leal, Ana; Badavelli, Stefania; Chalvet-Monfray, Karine; Ducrot, Christian; Abrial, David; Chabanne, Luc; Halos, Lénaïg

    2015-01-06

    Canine Monocytic Ehrlichiosis (CME), due to the bacterium Ehrlichia canis and transmitted by the brown dog tick Rhipicephalus sanguineus, is a major tick-borne disease in southern Europe. In this area, infections with other vector-borne pathogens (VBP) are also described and result in similar clinical expression. The aim of the present study was to evaluate the incidence risk of clinical CME in those endemic areas and to assess the potential involvement of other VBP in the occurrence of clinical and/or biological signs evocative of the disease. The study was conducted from April to November 2011 in veterinary clinics across Italy, Spain and Portugal. Sick animals were included when fitting at least three clinical and/or biological criteria compatible with ehrlichiosis. Serological tests (SNAP®4Dx, SNAP®Leish tests, Idexx, USA) and diagnostic PCR for E. canis, Anaplasma platys, Anaplasma phagocytophilum, Babesia spp, Hepatozoon canis and Leishmania infantum detection were performed to identify the etiological agents. Ehrlichiosis was considered when three clinical and/or biological suggestive signs were associated with at least one positive paraclinical test (serology or PCR). The annual incidence risk was calculated and data were geo-referenced for map construction. The probabilities of CME and other vector-borne diseases when facing clinical and/or biological signs suggestive of CME were then evaluated. A total of 366 dogs from 78 veterinary clinics were enrolled in the survey. Among them, 99 (27%) were confirmed CME cases, which allowed an estimation of the average annual incidence risk of CME amongst the investigated dog population to be 0.08%. Maps showed an increasing gradient of CME incidence risk from northern towards southern areas, in particular in Italy. It also suggested the existence of hot-spots of infections by VBP in Portugal. In addition, the detection of other VBP in the samples was common and the study demonstrated that a dog with clinical signs

  4. Field assessment of a model tuberculosis outbreak response plan for low-incidence areas

    Directory of Open Access Journals (Sweden)

    Pascopella Lisa

    2007-10-01

    Full Text Available Abstract Background For a regional project in four low-incidence states, we designed a customizable tuberculosis outbreak response plan. Prior to dissemination of the plan, a tuberculosis outbreak occurred, presenting an opportunity to perform a field assessment of the plan. The purpose of the assessment was to ensure that the plan included essential elements to help public health professionals recognize and respond to outbreaks. Methods We designed a semi-structured questionnaire and interviewed all key stakeholders involved in the response. We used common themes to assess validity of and identify gaps in the plan. A subset of participants provided structured feedback on the plan. Results We interviewed 11 public health and six community stakeholders. The assessment demonstrated that (1 almost all of the main response activities were reflected in the plan; (2 the plan added value by providing a definition of a tuberculosis outbreak and guidelines for communication and evaluation. These were areas that lacked written protocols during the actual outbreak response; and (3 basic education about tuberculosis and the interpretation and use of genotyping data were important needs. Stakeholders also suggested adding to the plan questions for evaluation and a section for specific steps to take when an outbreak is suspected. Conclusion An interactive field assessment of a programmatic tool revealed the value of a systematic outbreak response plan with a standard definition of a tuberculosis outbreak, guidelines for communication and evaluation, and response steps. The assessment highlighted the importance of education and training for tuberculosis in low-incidence areas.

  5. A new framework for interactive quality assessment with application to light field coding

    Science.gov (United States)

    Viola, Irene; Ebrahimi, Touradj

    2017-09-01

    In recent years, light field has experienced a surge of popularity, mainly due to the recent advances in acquisition and rendering technologies that have made it more accessible to the public. Thanks to image-based rendering techniques, light field contents can be rendered in real time on common 2D screens, allowing virtual navigation through the captured scenes in an interactive fashion. However, this richer representation of the scene poses the problem of reliable quality assessments for light field contents. In particular, while subjective methodologies that enable interaction have already been proposed, no work has been done on assessing how users interact with light field contents. In this paper, we propose a new framework to subjectively assess the quality of light field contents in an interactive manner and simultaneously track users behaviour. The framework is successfully used to perform subjective assessment of two coding solutions. Moreover, statistical analysis performed on the results shows interesting correlation between subjective scores and average interaction time.

  6. Free-Free Transitions in the Presence of Laser Fields and Debye Potential at Very Low Incident Electron Energies

    Science.gov (United States)

    Bhatia, Anand

    2012-01-01

    We study the free-free transition in electron-helium ion in the ground state and embedded in a Debye potential in the presence of an external laser field at very low incident electron energies. The laser field is treated classically while the collision dynamics is treated quantum mechanically. The laser field is chosen as monochromatic, linearly polarized and homogeneous. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing Volkov wave function for it. The scattering wave function for the incident electron on the target embedded in a Debye potential is solved numerically by taking into account the effect of electron exchange. We calculate the laser-assisted differential and total cross sections for free-free transition for absorption/emission of a single photon or no photon exchange. The results will be presented at the conference.

  7. Comparison of the incidence, nature and cause of injuries sustained on dirt field and artificial turf field by amateur football players

    Directory of Open Access Journals (Sweden)

    Kordi Ramin

    2011-02-01

    Full Text Available Abstract Background Data on the incidence, nature, severity and cause of match football injuries sustained on dirt field are scarce. The objectives of this study was to compare the incidence, nature, severity and cause of match injuries sustained on dirt field and artificial turf field by amateur male football players. Methods A prospective two-cohort design was employed. Participants were 252 male football players (mean age 27 years, range 18-43 in 14 teams who participated in a local championship carried on a dirt field and 216 male football players (mean age 28 years, range 17-40 in 12 teams who participated in a local championship carried on a artificial turf field in the same zone of the city. Injury definitions and recording procedures were compliant with the international consensus statement for epidemiological studies of injuries in football. Results The overall incidence of match injuries for men was 36.9 injuries/1000 player hours on dirt field and 19.5 on artificial turf (incidence rate ratio 1.88; 95% CI 1.19-3.05. Most common injured part on dirt field was ankle (26.7% and on artificial turf was knee (24.3%. The most common injury type in the dirt field was skin injuries (abrasion and laceration and in the artificial turf was sprain and ligament injury followed by haematoma/contusion/bruise. Most injuries were acute (artificial turf 89%, dirt field 91% and resulted from player-to-player contact (artificial turf 59.2%, dirt field 51.4%. Most injuries were slight and minimal in dirt field cohort but in artificial turf cohort the most injuries were mild. Conclusions There were differences in the incidence and type of football match injuries sustained on dirt field and artificial turf.

  8. Comparison of the incidence, nature and cause of injuries sustained on dirt field and artificial turf field by amateur football players.

    Science.gov (United States)

    Kordi, Ramin; Hemmati, Farajollah; Heidarian, Hamid; Ziaee, Vahid

    2011-02-09

    Data on the incidence, nature, severity and cause of match football injuries sustained on dirt field are scarce. The objectives of this study was to compare the incidence, nature, severity and cause of match injuries sustained on dirt field and artificial turf field by amateur male football players. A prospective two-cohort design was employed. Participants were 252 male football players (mean age 27 years, range 18-43) in 14 teams who participated in a local championship carried on a dirt field and 216 male football players (mean age 28 years, range 17-40) in 12 teams who participated in a local championship carried on a artificial turf field in the same zone of the city. Injury definitions and recording procedures were compliant with the international consensus statement for epidemiological studies of injuries in football. The overall incidence of match injuries for men was 36.9 injuries/1000 player hours on dirt field and 19.5 on artificial turf (incidence rate ratio 1.88; 95% CI 1.19-3.05).Most common injured part on dirt field was ankle (26.7%) and on artificial turf was knee (24.3%). The most common injury type in the dirt field was skin injuries (abrasion and laceration) and in the artificial turf was sprain and ligament injury followed by haematoma/contusion/bruise.Most injuries were acute (artificial turf 89%, dirt field 91%) and resulted from player-to-player contact (artificial turf 59.2%, dirt field 51.4%).Most injuries were slight and minimal in dirt field cohort but in artificial turf cohort the most injuries were mild. There were differences in the incidence and type of football match injuries sustained on dirt field and artificial turf.

  9. Light-induced gauge fields for ultracold atoms

    Science.gov (United States)

    Goldman, N.; Juzeliūnas, G.; Öhberg, P.; Spielman, I. B.

    2014-12-01

    Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms.

  10. Light-induced gauge fields for ultracold atoms

    International Nuclear Information System (INIS)

    Goldman, N; Juzeliūnas, G; Öhberg, P; Spielman, I B

    2014-01-01

    Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms. (review article)

  11. Quantum memory for nonstationary light fields based on controlled reversible inhomogeneous broadening

    International Nuclear Information System (INIS)

    Kraus, B.; Tittel, W.; Gisin, N.; Nilsson, M.; Kroell, S.; Cirac, J. I.

    2006-01-01

    We propose a method for efficient storage and recall of arbitrary nonstationary light fields, such as, for instance, single photon time-bin qubits or intense fields, in optically dense atomic ensembles. Our approach to quantum memory is based on controlled, reversible, inhomogeneous broadening and relies on a hidden time-reversal symmetry of the optical Bloch equations describing the propagation of the light field. We briefly discuss experimental realizations of our proposal

  12. High-Field Magnetization of Light Rare-Earth Metals

    DEFF Research Database (Denmark)

    McEwen, K.A.; Cock, G.J.; Roeland, L.W.

    1973-01-01

    The magnetization of single crystals of Eu, Sm, Nd, Pr, and Pr-Nd alloys has been measured in fields up to 37 T (370 kG). The results give new information on the magnetic properties of these metals. Of particular interest is a first-order transition from a nonmagnetic to a metamagnetic phase...... in double-hexagonal close-packed Pr, due to the crossing of crystal-field levels, when a field of about 32 T is applied in the hard direction at low temperatures....

  13. Light-like tachyon condensation in open string field theory

    Czech Academy of Sciences Publication Activity Database

    Hellerman, S.; Schnabl, Martin

    2013-01-01

    Roč. 2013, č. 4 (2013), s. 1-34 ISSN 1126-6708 Institutional support: RVO:68378271 Keywords : string field theory * tachyon condensation Subject RIV: BE - Theoretical Physics Impact factor: 5.618, year: 2012

  14. Testing Chameleon Theories with Light Propagating through a Magnetic Field

    OpenAIRE

    Brax, P.; van de Bruck, C.; Davis, A. C.; Mota, D. F.; Shaw, D. J.

    2007-01-01

    It was recently argued that the observed PVLAS anomaly can be explained by chameleon field theories in which large deviations from Newton's law can be avoided. Here we present the predictions for the dichroism and the birefringence induced in the vacuum by a magnetic field in these models. We show that chameleon particles behave very differently from standard axion-like particles (ALPs). We find that, unlike ALPs, the chameleon particles are confined within the experimental set-up. As a conse...

  15. Two-stream instability for a light ion beam-plasma system with external magnetic field

    International Nuclear Information System (INIS)

    Okada, T.; Tazawa, H.

    1992-12-01

    For inertial confinement fusion, a focused light ion beam (LIB) is required to propagate stably through a chamber to a target. We have pointed out that the applied external magnetic field is important for LIB propagation. To investigate the influence of the external magnetic field on the LIB propagation, we analysed the electrostatic dispersion relation of magnetized light ion beam-plasma system. The particle in-cell (PIC) simulation results are presented for a light ion beam-plasma system with external magnetic field. (author)

  16. Constraints and Hamiltonian in light-front quantized field theory

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1993-01-01

    Self-consistent hamiltonian formulation of scalar theory on the null plane is constructed and quantized following the Dirac procedure. The theory contains also constraint equations which would give, if solved, to a nonlocal Hamiltonian. In contrast to the equal-time formulation we obtain a different description of the spontaneous symmetry breaking in the continuum and the symmetry generators are found to annihilate the light-front vacuum. Two examples are given where the procedure cannot be applied self-consistently. The corresponding theories are known to be ill-defined from the equal-time quantization. (author)

  17. Modulation of horizontal cell receptive fields in the light adapted goldfish retina

    NARCIS (Netherlands)

    Verweij, J.; Kamermans, M.; van den Aker, E. C.; Spekreijse, H.

    1996-01-01

    In the isolated goldfish retina, 700 nm background illumination increases the horizontal cell receptive field size, as measured with 565 nm slits of light, but decreases the receptive field size, when measured with 660 nm slits. These background-induced changes in receptive field size are absent

  18. Atomic and Free Electrons in a Strong Light Field

    International Nuclear Information System (INIS)

    Fedorov, Mikhail V.

    1998-02-01

    This book presents and describes a series of unusual and striking strong-field phenomena concerning atoms and free electrons. Some of these phenomena are: multiphoton stimulated Bremsstrahlung, free-electron lasers, ave-packet physics, above-threshold ionization, and strong-field stabilization in Rydberg atoms. The theoretical foundations and causes of the phenomena are described in detail, with all the approximations and derivations discussed. All the known and relevant experiments are described oo, and their results are compared with those of the existing theoretical models. An extensive general theoretical introduction gives a good basis for subsequent parts of the book and is an independent and self-sufficient description of the most efficient theoretical methods of the strong-field and multiphoton physics. This book can serve as a textbook for graduate students

  19. Radiation of Electron in the Field of Plane Light Wave

    International Nuclear Information System (INIS)

    Zelinsky, A.; Drebot, I.V.; Grigorev, Yu.N.; Zvonareva, O.D.; Tatchyn, R.

    2006-01-01

    Results of integration of a Lorentz equation for a relativistic electron moving in the field of running, plane, linear polarized electromagnetic wave are presented in the paper. It is shown that electron velocities in the field of the wave are almost periodic functions of time. For calculations of angular spectrum of electron radiation intensity expansion of the electromagnetic field in a wave zone into generalized Fourier series was used. Expressions for the radiation intensity spectrum are presented in the paper. Derived results are illustrated for electron and laser beam parameters of NSC KIPT X-ray generator NESTOR. It is shown that for low intensity of the interacting electromagnetic wave the results of energy and angular spectrum calculations in the frame of classical electrodynamics completely coincide with calculation results produced using quantum electrodynamics. Simultaneously, derived expressions give possibilities to investigate dependence of energy and angular Compton radiation spectrum on phase of interaction and the interacting wave intensity

  20. Globally and locally supersymmetric effective theories for light fields

    CERN Document Server

    Brizi, Leonardo; Scrucca, Claudio A

    2009-01-01

    We reconsider the general question of how to characterize most efficiently the low-energy effective theory obtained by integrating out heavy modes in globally and locally supersymmetric theories. We consider theories with chiral and vector multiplets and identify the conditions under which an approximately supersymmetric low-energy effective theory can exist. These conditions translate into the requirements that all the derivatives, fermions and auxiliary fields should be small in units of the heavy mass scale. They apply not only to the matter sector, but also to the gravitational one if present, and imply in that case that the gravitino mass should be small. We then show how to determine the unique exactly supersymmetric theory that approximates this effective theory at the lowest order in the counting of derivatives, fermions and auxiliary fields, by working both at the superfield level and with component fields. As a result we give a simple prescription for integrating out heavy superfields in an algebrai...

  1. Testing chameleon theories with light propagating through a magnetic field

    International Nuclear Information System (INIS)

    Brax, Philippe; Bruck, Carsten van de; Davis, Anne-Christine; Mota, David F.; Shaw, Douglas

    2007-01-01

    It was recently argued that the observed PVLAS anomaly can be explained by chameleon field theories in which large deviations from Newton's law can be avoided. Here we present the predictions for the dichroism and the birefringence induced in the vacuum by a magnetic field in these models. We show that chameleon particles behave very differently from standard axionlike particles (ALPs). We find that, unlike ALPs, the chameleon particles are confined within the experimental setup. As a consequence, the birefringence is always bigger than the dichroism in PVLAS-type experiments

  2. Atomic and free electrons in a strong light field

    CERN Document Server

    Fedorov, Mikhail V

    1997-01-01

    This book presents and describes a series of unusual and striking strong-field phenomena concerning atoms and free electrons. Some of these phenomena are: multiphoton stimulated bremsstrahlung, free-electron lasers, wave-packet physics, above-threshold ionization, and strong-field stabilization in Rydberg atoms. The theoretical foundations and causes of the phenomena are described in detail, with all the approximations and derivations discussed. All the known and relevant experiments are described too, and their results are compared with those of the existing theoretical models.An extensive ge

  3. Light-cone gauge approach to arbitrary spin fields, currents and shadows

    International Nuclear Information System (INIS)

    Metsaev, R R

    2014-01-01

    Totally symmetric arbitrary spin fields in AdS space, conformal fields, conformal currents, and shadow fields in flat space are studied. Light-cone gauge formulations for such fields, currents and shadows are obtained. Use of the Poincaré parametrization of AdS space and ladder operators allows us to treat fields in flat and AdS spaces on an equal footing. Light-cone gauge realization of relativistic symmetries for fields, currents and shadows is also obtained. The light-cone gauge formulation for fields is obtained by using the gauge invariant Lagrangian which is presented in terms of modified de Donder divergence, while the light-cone gauge formulation for currents and shadows is obtained by using the gauge invariant approach to currents and shadows. This allows us to demonstrate explicitly how the ladder operators entering the gauge invariant formulation of fields, currents and shadows manifest themselves in the light-cone gauge formulation for fields, currents and shadows. (paper)

  4. The Cytocam video microscope. A new method for visualising the microcirculation using Incident Dark Field technology.

    Science.gov (United States)

    Hutchings, Sam; Watts, Sarah; Kirkman, Emrys

    2016-01-01

    We report a new microcirculatory assessment device, the Braedius Cytocam, an Incident Dark Field (IDF) video microscope, and compare it with a precursor device utilising side stream dark field (SDF) imaging. Time matched measurements were made with both devices from the sublingual microcirculation of pigs subjected to traumatic injury and hemorrhagic shock at baseline and during a shock phase. Images were analysed for vessel density, microcirculatory flow and image quality. There were no differences in density or flow data recorded from the two devices at baseline [TVD IDF 14.2 ± 2.4/TVD SDF 13.2 ± 2.0, p 0.17] [MFI IDF 3 (2.8-3.0)/MFI SDF 3 (2.9-3.0), p 0.36] or during the shock state [TVD IDF 11.64 ± 3.3/TVD SDF 11.4 ± 4.0 p = 0.98] [MFI IDF 1.9 (0.6-2.7)/MFI SDF 1.7 (0.3-2.6) p 0.55]. Bland and Altman analysis showed no evidence of significant bias. Vessel contrast was significantly better with the IDF device for both capillaries [17.1 ± 3.9 (IDF) v 3.4 ± 3.6 (SDF), p = 0.0006] and venules [36.1 ± 11.4 (IDF) v 26.4 ± 7.1 (SDF) p 0.014] The Braedius Cytocam showed comparable vessel detection to a precursor device during both baseline and low flow (shock) states.

  5. A finite element propagation model for extracting normal incidence impedance in nonprogressive acoustic wave fields

    Science.gov (United States)

    Watson, Willie R.; Jones, Michael G.; Tanner, Sharon E.; Parrott, Tony L.

    1995-01-01

    A propagation model method for extracting the normal incidence impedance of an acoustic material installed as a finite length segment in a wall of a duct carrying a nonprogressive wave field is presented. The method recasts the determination of the unknown impedance as the minimization of the normalized wall pressure error function. A finite element propagation model is combined with a coarse/fine grid impedance plane search technique to extract the impedance of the material. Results are presented for three different materials for which the impedance is known. For each material, the input data required for the prediction scheme was computed from modal theory and then contaminated by random error. The finite element method reproduces the known impedance of each material almost exactly for random errors typical of those found in many measurement environments. Thus, the method developed here provides a means for determining the impedance of materials in a nonprogressirve wave environment such as that usually encountered in a commercial aircraft engine and most laboratory settings.

  6. Effect of air flow, panel curvature, and internal pressurization on field-incidence transmission loss

    Science.gov (United States)

    Koval, L. R.

    1976-01-01

    In the context of sound transmission through aircraft fuselage panels, equations for the field-incidence transmission loss (TL) of a single-walled panel are derived that include the effects of external air flow, panel curvature, and internal fuselage pressurization. Flow is shown to provide a modest increase in TL that is uniform with frequency up to the critical frequency. The increase is about 2 dB at Mach number M = 0.5, and about 3.5 dB at M = 1. Above the critical frequency where TL is damping controlled, the increase can be slightly larger at certain frequencies. Curvature is found to stiffen the panel, thereby increasing the TL at low frequencies, but also to introduce a dip at the 'ring frequency' of a full cylinder having the same radius as the panel. Pressurization appears to produce a slight decrease in TL throughout the frequency range, and also slightly shifts the dips at the critical frequency and at the ring frequency.

  7. Exploiting the return on experience of incidents in the field of industrial radiography

    International Nuclear Information System (INIS)

    Bataille, C.; Crouail, P.; Gauron, C.; Abela, G.; Martin, E.

    2008-01-01

    After a presentation of the RELIR network (a French system of return on experience on radiological incidents), the aim of which is to collect typical incidents in different activity sectors (industry, medicine, veterinary, research, teaching, transports) in order to report them during professional training sessions, the authors briefly present some new files which have been recently produced. They deal with incidents due to a failing marking-out, intentional marking overstepping during non destructive testing, incomplete evacuation of the exclusion zone during non destructive testing and irradiation of an operator during a gamma-graphic shot, incident during a training session

  8. Integrated vehicle-based safety systems light-vehicle field operational test key findings report.

    Science.gov (United States)

    2011-01-01

    "This document presents key findings from the light-vehicle field operational test conducted as part of the Integrated Vehicle-Based Safety Systems program. These findings are the result of analyses performed by the University of Michigan Transportat...

  9. Integrated vehicle-based safety systems light-vehicle field operational test, methodology and results report.

    Science.gov (United States)

    2010-12-01

    "This document presents the methodology and results from the light-vehicle field operational test conducted as part of the Integrated Vehicle-Based Safety Systems program. These findings are the result of analyses performed by the University of Michi...

  10. Integrated vehicle-based safety systems (IVBSS) : light vehicle platform field operational test data analysis plan.

    Science.gov (United States)

    2009-12-22

    This document presents the University of Michigan Transportation Research Institutes plan to : perform analysis of data collected from the light vehicle platform field operational test of the : Integrated Vehicle-Based Safety Systems (IVBSS) progr...

  11. Nonlinear magneto-optical rotation with modulated light in tilted magnetic fields

    International Nuclear Information System (INIS)

    Pustelny, S.; Gawlik, W.; Rochester, S. M.; Kimball, D. F. Jackson; Yashchuk, V. V.; Budker, D.

    2006-01-01

    Larmor precession of laser-polarized atoms contained in antirelaxation-coated cells, detected via nonlinear magneto-optical rotation (NMOR), is a promising technique for a new generation of ultrasensitive atomic magnetometers. For magnetic fields directed along the light propagation direction, resonances in NMOR appear when linearly polarized light is frequency or amplitude modulated at twice the Larmor frequency. Because the frequency of these resonances depends on the magnitude but not the direction of the field, they are useful for scalar magnetometry. Additional NMOR resonances at the Larmor frequency appear when the magnetic field is tilted away from the light propagation direction in the plane defined by the light propagation and polarization vectors. These resonances, studied both experimentally and with a density matrix calculation in the present work, offer a convenient method of achieving additional information about a direction of the magnetic field

  12. Ray calibration and phase mapping for structured-light-field 3D reconstruction.

    Science.gov (United States)

    Cai, Zewei; Liu, Xiaoli; Peng, Xiang; Gao, Bruce Z

    2018-03-19

    In previous work, we presented a structured light field (SLF) method combining light field imaging with structured illumination to perform multi-view depth measurement. However, the previous work just accomplishes depth rather than 3D reconstruction. In this paper, we propose a novel active method involving ray calibration and phase mapping, to achieve SLF 3D reconstruction. We performed the ray calibration for the first time to determine each light field ray with metric spatio-angular parameters, making the SLF realize multi-view 3D reconstruction. Based on the ray parametric equation, we further derived the phase mapping in the SLF that spatial coordinates can be directly mapped from phase. A flexible calibration strategy was correspondently designed to determine mapping coefficients for each light field ray, achieving high-efficiency SLF 3D reconstruction. Experimental results demonstrated that the proposed method was suitable for high-efficiency multi-view 3D reconstruction in the SLF.

  13. Generalized laws of refraction that can lead to wave-optically forbidden light-ray fields.

    Science.gov (United States)

    Courtial, Johannes; Tyc, Tomáš

    2012-07-01

    The recent demonstration of a metamaterial phase hologram so thin that it can be classified as an interface in the effective-medium approximation [Science 334, 333 (2011)] has dramatically increased interest in generalized laws of refraction. Based on the fact that scalar wave optics allows only certain light-ray fields, we divide generalized laws of refraction into two categories. When applied to a planar cross section through any allowed light-ray field, the laws in the first category always result in a cross section through an allowed light-ray field again, whereas the laws in the second category can result in a cross section through a forbidden light-ray field.

  14. Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

    NARCIS (Netherlands)

    Zendejas, Dominguez J.; Koppenhoefer, J.; Saglia, R.; Birkby, J.L.; Hodgkin, S.; Kovács, G.; Pinfield, D.; Sipocz, B.; Barrado, D.; Bender, R.; Burgo, del C.; Cappetta, M.; Martín, E.; Nefs, B.; Riffeser, A.; Steele, P.

    2013-01-01

    The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light

  15. Field study of visual and biological light conditions of independently-living elderly people

    NARCIS (Netherlands)

    Aarts, M.P.J.; Westerlaken, A.C.

    2005-01-01

    A field study was carried out to learn more about the influence of light on the lives of elderly people . The results should lead to the development and design of a light concept for elderly people that will improve their everyday health and well-being. Methods: Ninetyone independently-living

  16. Globally and locally supersymmetric effective theories for light fields

    International Nuclear Information System (INIS)

    Brizi, Leonardo; Gomez-Reino, Marta; Scrucca, Claudio A.

    2009-01-01

    We reconsider the general question of how to characterize most efficiently the low-energy effective theory obtained by integrating out heavy modes in globally and locally supersymmetric theories. We consider theories with chiral and vector multiplets and identify the conditions under which an approximately supersymmetric low-energy effective theory can exist. These conditions translate into the requirements that all the derivatives, fermions and auxiliary fields should be small in units of the heavy mass scale. They apply not only to the matter sector, but also to the gravitational one if present, and imply in that case that the gravitino mass should be small. We then show how to determine the unique exactly supersymmetric theory that approximates this effective theory at the lowest order in the counting of derivatives, fermions and auxiliary fields, by working both at the superfield level and with component fields. As a result we give a simple prescription for integrating out heavy superfields in an algebraic and manifestly supersymmetric way, which turns out to hold in the same form both for globally and locally supersymmetric theories, meaning that the process of integrating out heavy modes commutes with the process of switching on gravity. More precisely, for heavy chiral and vector multiplets one has to impose respectively stationarity of the superpotential and the Kaehler potential.

  17. Linked and knotted beams of light, conservation of helicity and the flow of null electromagnetic fields

    International Nuclear Information System (INIS)

    Irvine, William T M

    2010-01-01

    Maxwell's equations allow for some remarkable solutions consisting of pulsed beams of light which have linked and knotted field lines. The preservation of the topological structure of the field lines in these solutions has previously been ascribed to the fact that the electric and magnetic helicities, a measure of the degree of linking and knotting between field lines, are conserved. Here we show that the elegant evolution of the field is due to the stricter condition that the electric and magnetic fields be everywhere orthogonal. The field lines then satisfy a 'frozen field' condition and evolve as if they were unbreakable filaments embedded in a fluid. The preservation of the orthogonality of the electric and magnetic field lines is guaranteed for null, shear-free fields such as the ones considered here by a theorem of Robinson. We calculate the flow field of a particular solution and find it to have the form of a Hopf fibration moving at the speed of light in a direction opposite to the propagation of the pulsed light beam, a familiar structure in this type of solution. The difference between smooth evolution of individual field lines and conservation of electric and magnetic helicities is illustrated by considering a further example in which the helicities are conserved, but the field lines are not everywhere orthogonal. The field line configuration at time t = 0 corresponds to a nested family of torus knots but unravels upon evolution.

  18. A covariant formulation of the relativistic Hamiltonian theory on the light cone (fields with spin)

    International Nuclear Information System (INIS)

    Atakishiev, N.M.; Mir-Kasimov, R.M.; Nagiyev, Sh.M.

    1978-01-01

    A Hamiltonian formulation of quantum field theory on the light cone, developed earlier, is extended to the case of particles with spin. The singularities accompanying each field theory in light-front variables are removed by the introduction of an infinite number of counterterms of a new type, which can be included into the interaction Hamiltonian. A three-dimensional diagram technique is formulated, which is applied to calculate the fermion self-energy in the lowest order of perturbation theory

  19. Enhancing the performance of the light field microscope using wavefront coding.

    Science.gov (United States)

    Cohen, Noy; Yang, Samuel; Andalman, Aaron; Broxton, Michael; Grosenick, Logan; Deisseroth, Karl; Horowitz, Mark; Levoy, Marc

    2014-10-06

    Light field microscopy has been proposed as a new high-speed volumetric computational imaging method that enables reconstruction of 3-D volumes from captured projections of the 4-D light field. Recently, a detailed physical optics model of the light field microscope has been derived, which led to the development of a deconvolution algorithm that reconstructs 3-D volumes with high spatial resolution. However, the spatial resolution of the reconstructions has been shown to be non-uniform across depth, with some z planes showing high resolution and others, particularly at the center of the imaged volume, showing very low resolution. In this paper, we enhance the performance of the light field microscope using wavefront coding techniques. By including phase masks in the optical path of the microscope we are able to address this non-uniform resolution limitation. We have also found that superior control over the performance of the light field microscope can be achieved by using two phase masks rather than one, placed at the objective's back focal plane and at the microscope's native image plane. We present an extended optical model for our wavefront coded light field microscope and develop a performance metric based on Fisher information, which we use to choose adequate phase masks parameters. We validate our approach using both simulated data and experimental resolution measurements of a USAF 1951 resolution target; and demonstrate the utility for biological applications with in vivo volumetric calcium imaging of larval zebrafish brain.

  20. LC-lens array with light field algorithm for 3D biomedical applications

    Science.gov (United States)

    Huang, Yi-Pai; Hsieh, Po-Yuan; Hassanfiroozi, Amir; Martinez, Manuel; Javidi, Bahram; Chu, Chao-Yu; Hsuan, Yun; Chu, Wen-Chun

    2016-03-01

    In this paper, liquid crystal lens (LC-lens) array was utilized in 3D bio-medical applications including 3D endoscope and light field microscope. Comparing with conventional plastic lens array, which was usually placed in 3D endoscope or light field microscope system to record image disparity, our LC-lens array has higher flexibility of electrically changing its focal length. By using LC-lens array, the working distance and image quality of 3D endoscope and microscope could be enhanced. Furthermore, the 2D/3D switching ability could be achieved if we turn off/on the electrical power on LClens array. In 3D endoscope case, a hexagonal micro LC-lens array with 350um diameter was placed at the front end of a 1mm diameter endoscope. With applying electric field on LC-lens array, the 3D specimen would be recorded as from seven micro-cameras with different disparity. We could calculate 3D construction of specimen with those micro images. In the other hand, if we turn off the electric field on LC-lens array, the conventional high resolution 2D endoscope image would be recorded. In light field microscope case, the LC-lens array was placed in front of the CMOS sensor. The main purpose of LC-lens array is to extend the refocusing distance of light field microscope, which is usually very narrow in focused light field microscope system, by montaging many light field images sequentially focusing on different depth. With adjusting focal length of LC-lens array from 2.4mm to 2.9mm, the refocusing distance was extended from 1mm to 11.3mm. Moreover, we could use a LC wedge to electrically shift the optics axis and increase the resolution of light field.

  1. Measurement of the sound power incident on the walls of a reverberation room with near field acoustic holography

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Tiana Roig, Elisabet

    2010-01-01

    area; and it has always been regarded as impossible to measure the sound power that is incident on a wall directly. This paper examines a new method of determining this quantity from sound pressure measurements at positions on the wall using 'statistically optimised near field acoustic holography...

  2. Recent advances in head-mounted light field displays for virtual and augmented reality (Conference Presentation)

    Science.gov (United States)

    Hua, Hong

    2017-02-01

    Head-mounted light field displays render a true 3D scene by sampling either the projections of the 3D scene at different depths or the directions of the light rays apparently emitted by the 3D scene and viewed from different eye positions. They are capable of rendering correct or nearly correct focus cues and addressing the very well-known vergence-accommodation mismatch problem in conventional virtual and augmented reality displays. In this talk, I will focus on reviewing recent advancements of head-mounted light field displays for VR and AR applications. I will demonstrate examples of HMD systems developed in my group.

  3. Electric dipole moments of light nuclei in effective field theory

    Energy Technology Data Exchange (ETDEWEB)

    Bsaisou, Jan; Liebig, Susanna; Minossi, David [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany); Hanhart, Christoph; Nogga, Andreas; Vries, Jordy de; Wirzba, Andreas [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich (Germany); JARA - Forces and Matter Experiments, Forschungszentrum Juelich (Germany); Meissner, UlfG. [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich (Germany); JARA - Forces and Matter Experiments, Forschungszentrum Juelich (Germany); Helmholtz-Institut fuer Strahlen und Kernphysik, Universitaet Bonn (Germany)

    2014-07-01

    Electric dipole moments (EDMs) break parity (P) and time-reversal (T) symmetry and thus, by the CPT-theorem, CP-symmetry. Once measured, they will be unambiguous signs of new physics since CP-violation from the standard mechanism predicts EDMs that are experimentally inaccessible in the foreseeable future. We calculate within the framework of effective field theory the two-nucleon contributions to the EDMs of the deuteron, helion, and triton induced by P- and T-violating terms that arise from the QCD θ-term or dimension-6 sources of physics beyond the Standard Model (SM). We demonstrate what insights into physics beyond the SM can be gained from a suitable combination of measurements and, if needed, supplementary lattice QCD calculations.

  4. Field evaluation of a new light trap for phlebotomine sand flies.

    Science.gov (United States)

    Gaglio, Gabriella; Napoli, Ettore; Falsone, Luigi; Giannetto, Salvatore; Brianti, Emanuele

    2017-10-01

    Light traps are one of the most common attractive method for the collection of nocturnal insects. Although light traps are generally referred to as "CDC light traps", different models, equipped with incandescent or UV lamps, have been developed. A new light trap, named Laika trap 3.0, equipped with LED lamps and featured with a light and handy design, has been recently proposed into the market. In this study we tested and compared the capture performances of this new trap with those of a classical light trap model under field conditions. From May to November 2013, a Laika trap and a classical light trap were placed biweekly in an area endemic for sand flies. A total of 256 sand fly specimens, belonging to 3 species (Sergentomyia minuta, Phlebotomus perniciosus, Phlebotomus neglectus) were collected during the study period. The Laika trap captured 126 phlebotomine sand flies: P. perniciosus (n=38); S. minuta (n=88), a similar number of specimens (130) and the same species were captured by classical light trap which collected also 3 specimens of P. neglectus. No significant differences in the capture efficiency at each day of trapping, neither in the number of species or in the sex of sand flies were observed. According to results of this study, the Laika trap may be a valid alternative to classical light trap models especially when handy design and low power consumption are key factors in field studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Automated and observer based light field indicator edge evaluation in diagnostic X-ray equipment

    Directory of Open Access Journals (Sweden)

    Márcio Bottaro

    Full Text Available Abstract Introduction To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and naïve human observers were asked to mark the light field edge according to their own determination. Different interpretations of the contrast were then calculated and compared. Results In contrast to automated measurements of edge definition and detection, measurements by human observers showed large inter-observer variation independent of their training with X-ray equipment. Different contrast calculations considering the different edge definitions gave very different contrast values. Conclusion As the main conclusion, we propose a more exact edge definition of the X-ray light field, corresponding well to the average human observer’s edge determination. The new edge definition method with automated systems would reduce human variability in edge determination. Such errors could potentially affect the approval of X-ray equipment, and also increase the radiation dose. The automated measurement based on human observers’ edge definition and the corresponding contrast calculation may lead to a more precise light field calibration, which enables reduced irradiation doses on radiology patients.

  6. Automated and observer based light field indicator edge evaluation in diagnostic X-ray equipment

    International Nuclear Information System (INIS)

    Bottaro, Marcio; Nagy, Balazs Vince; Soares, Fernanda Cristina Salvador; Rosendo, Danilo Cabral

    2017-01-01

    Introduction: To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods: Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and naive human observers were asked to mark the light field edge according to their own determination. Different interpretations of the contrast were then calculated and compared. Results: In contrast to automated measurements of edge definition and detection, measurements by human observers showed large inter-observer variation independent of their training with X-ray equipment. Different contrast calculations considering the different edge definitions gave very different contrast values. Conclusion: As the main conclusion, we propose a more exact edge definition of the X-ray light field, corresponding well to the average human observer's edge determination. The new edge definition method with automated systems would reduce human variability in edge determination. Such errors could potentially affect the approval of X-ray equipment, and also increase the radiation dose. The automated measurement based on human observers’ edge definition and the corresponding contrast calculation may lead to a more precise light field calibration, which enables reduced irradiation doses on radiology patients. (author)

  7. Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

    Directory of Open Access Journals (Sweden)

    Vamsi Kiran Adhikarla

    2015-04-01

    Full Text Available This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  8. Automated and observer based light field indicator edge evaluation in diagnostic X-ray equipment

    Energy Technology Data Exchange (ETDEWEB)

    Bottaro, Marcio; Nagy, Balazs Vince; Soares, Fernanda Cristina Salvador; Rosendo, Danilo Cabral, E-mail: marcio@iee.usp.br [Universidade de Sao Paulo (USP), SP (Brazil); Optics and Engineering Informatics, Budapest University of Technology and Economics, Budapest (Hungary)

    2017-04-15

    Introduction: To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods: Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and naive human observers were asked to mark the light field edge according to their own determination. Different interpretations of the contrast were then calculated and compared. Results: In contrast to automated measurements of edge definition and detection, measurements by human observers showed large inter-observer variation independent of their training with X-ray equipment. Different contrast calculations considering the different edge definitions gave very different contrast values. Conclusion: As the main conclusion, we propose a more exact edge definition of the X-ray light field, corresponding well to the average human observer's edge determination. The new edge definition method with automated systems would reduce human variability in edge determination. Such errors could potentially affect the approval of X-ray equipment, and also increase the radiation dose. The automated measurement based on human observers’ edge definition and the corresponding contrast calculation may lead to a more precise light field calibration, which enables reduced irradiation doses on radiology patients. (author)

  9. Exploring direct 3D interaction for full horizontal parallax light field displays using leap motion controller.

    Science.gov (United States)

    Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

    2015-04-14

    This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  10. Near-Infrared to Visible Organic Upconversion Devices Based on Organic Light-Emitting Field Effect Transistors.

    Science.gov (United States)

    Li, Dongwei; Hu, Yongsheng; Zhang, Nan; Lv, Ying; Lin, Jie; Guo, Xiaoyang; Fan, Yi; Luo, Jinsong; Liu, Xingyuan

    2017-10-18

    The near-infrared (NIR) to visible upconversion devices have attracted great attention because of their potential applications in the fields of night vision, medical imaging, and military security. Herein, a novel all-organic upconversion device architecture has been first proposed and developed by incorporating a NIR absorption layer between the carrier transport layer and the emission layer in heterostructured organic light-emitting field effect transistors (OLEFETs). The as-prepared devices show a typical photon-to-photon upconversion efficiency as high as 7% (maximum of 28.7% under low incident NIR power intensity) and millisecond-scale response time, which are the highest upconversion efficiency and one of the fastest response time among organic upconversion devices as referred to the previous reports up to now. The high upconversion performance mainly originates from the gain mechanism of field-effect transistor structures and the unique advantage of OLEFETs to balance between the photodetection and light emission. Meanwhile, the strategy of OLEFETs also offers the advantage of high integration so that no extra OLED is needed in the organic upconversion devices. The results would pave way for low-cost, flexible and portable organic upconversion devices with high efficiency and simplified processing.

  11. Evanescent field: A potential light-tool for theranostics application

    Science.gov (United States)

    Polley, Nabarun; Singh, Soumendra; Giri, Anupam; Pal, Samir Kumar

    2014-03-01

    A noninvasive or minimally invasive optical approach for theranostics, which would reinforce diagnosis, treatment, and preferably guidance simultaneously, is considered to be major challenge in biomedical instrument design. In the present work, we have developed an evanescent field-based fiber optic strategy for the potential theranostics application in hyperbilirubinemia, an increased concentration of bilirubin in the blood and is a potential cause of permanent brain damage or even death in newborn babies. Potential problem of bilirubin deposition on the hydroxylated fiber surface at physiological pH (7.4), that masks the sensing efficacy and extraction of information of the pigment level, has also been addressed. Removal of bilirubin in a blood-phantom (hemoglobin and human serum albumin) solution from an enhanced level of 77 μM/l (human jaundice >50 μM/l) to ˜30 μM/l (normal level ˜25 μM/l in human) using our strategy has been successfully demonstrated. In a model experiment using chromatography paper as a mimic of biological membrane, we have shown efficient degradation of the bilirubin under continuous monitoring for guidance of immediate/future course of action.

  12. Crystal fields at light rare-earth ions in Y and Lu

    DEFF Research Database (Denmark)

    Touborg, P.; Nevald, Rolf; Johansson, Torben

    1978-01-01

    Crystal-field parameters have been deduced for the light rare-earth solutes Ce, Pr, and Nd in Y or Lu hosts from measurements of the paramagnetic susceptibilities. In the analysis all multiplets in the lowest LS term were included. For a given host, crystal-field parameters divided by Stevens fac...

  13. Dynamic generation and coherent control of beating stationary light pulses by a microwave coupling field in five-level cold atoms

    Science.gov (United States)

    Bao, Qian-Qian; Zhang, Yan; Cui, Cui-Li; Meng, Shao-Ying; Fang, You-Wei; Tian, Xue-Dong

    2018-04-01

    We propose an efficient scheme for generating and controlling beating stationary light pulses in a five-level atomic sample driven into electromagnetically induced transparency condition. This scheme relies on an asymmetrical procedure of light storage and retrieval tuned by two counter-propagating control fields where an additional coupling field, such as the microwave field, is introduced in the retrieval stage. A quantum probe field, incident upon such an atomic sample, is first transformed into spin coherence excitation of the atoms and then retrieved as beating stationary light pulses exhibiting a series of maxima and minima in intensity due to the alternative constructive and destructive interference. It is convenient to control the beating stationary light pulses just by manipulating the intensity and detuning of the additional microwave field. This interesting phenomenon involves in fact the coherent manipulation of dark-state polaritons and could be explored to achieve the efficient temporal splitting of stationary light pulses and accurate measurement of the microwave intensity.

  14. Radiative transfer modeling of upwelling light field in coastal waters

    International Nuclear Information System (INIS)

    Sundarabalan, Balasubramanian; Shanmugam, Palanisamy; Manjusha, Sadasivan

    2013-01-01

    Numerical simulations of the radiance distribution in coastal waters are a complex problem, but playing a growingly important role in optical oceanography and remote sensing applications. The present study attempts to modify the Inherent Optical Properties (IOPs) to allow the phase function to vary with depth, and the bottom boundary to take into account a sloping/irregular surface and the effective reflectance of the bottom material. It then uses the Hydrolight numerical model to compute Apparent Optical Properties (AOPs) for modified IOPs and bottom boundary conditions compared to the default values available in the standard Hydrolight model. The comparison of the profiles of upwelling radiance simulated with depth-dependent IOPs as well as modified bottom boundary conditions for realistic cases of coastal waters off Point Calimere of southern India shows a good match between the simulated and measured upwelling radiance profile data, whereas there is a significant drift between the upwelling radiances simulated from the standard Hydrolight model (with default values) and measured data. Further comparison for different solar zenith conditions at a coastal station indicates that the upwelling radiances simulated with the depth-dependent IOPs and modified bottom boundary conditions are in good agreement with the measured radiance profile data. This simulation captures significant changes in the upwelling radiance field influenced by the bottom boundary layer as well. These results clearly emphasize the importance of using realistic depth-dependent IOPs as well as bottom boundary conditions as input to Hydrolight in order to obtain more accurate AOPs in coastal waters. -- Highlights: ► RT model with depth-dependent IOPs and modified bottom boundary conditions provides accurate L u profiles in coastal waters. ► The modified phase function model will be useful for coastal waters. ► An inter-comparison with measured upwelling radiance gives merits of the

  15. Lighting.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  16. Extreme field limits in the interaction of laser light with ultrarelativistic electrons

    Energy Technology Data Exchange (ETDEWEB)

    Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kando, M.; Kiriyama, H.; Koga, J.; Kondo, K.; Kotaki, H.; Pirozhkov, A.; Bulanov, S. S.; Zhidkov, A.; Chen, P.; Neely, D.; Kato, Y.; Narozhny, N. B.; Korn, G. [Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); University of California, Berkeley, CA 94720 (United States); Osaka University, Osaka 565-0871 (Japan); National Taiwan University, Taipei 10617, Taiwan (China); Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202 (Japan); Moscow Engineering Physics Institute (State University), Moscow 115409 (Russian Federation); Max-Planck-Institut fuer Quantenoptik, Garching 85748 (Germany) and ELI Beamline Facility, Institute of Physics, CAS, Prague 18221 (Czech Republic)

    2012-07-11

    The critical electric field of quantum electrodynamics is so strong that it produces electron-positron pairs from vacuum, converting the energy of light into matter. This field has become feasible through the construction of extremely high power lasers or/and with the sophisticated use of nonlinear processes in relativistic plasmas. A feasibility of the experiments on the collision of laser light and high intensity electromagnetic pulses, generated by relativistic flying mirrors, with relativistic electrons for the studying of extreme field limits in the nonlinear interaction of electromagnetic waves is discussed.

  17. Field-based dynamic light scattering microscopy: theory and numerical analysis.

    Science.gov (United States)

    Joo, Chulmin; de Boer, Johannes F

    2013-11-01

    We present a theoretical framework for field-based dynamic light scattering microscopy based on a spectral-domain optical coherence phase microscopy (SD-OCPM) platform. SD-OCPM is an interferometric microscope capable of quantitative measurement of amplitude and phase of scattered light with high phase stability. Field-based dynamic light scattering (F-DLS) analysis allows for direct evaluation of complex-valued field autocorrelation function and measurement of localized diffusive and directional dynamic properties of biological and material samples with high spatial resolution. In order to gain insight into the information provided by F-DLS microscopy, theoretical and numerical analyses are performed to evaluate the effect of numerical aperture of the imaging optics. We demonstrate that sharp focusing of fields affects the measured diffusive and transport velocity, which leads to smaller values for the dynamic properties in the sample. An approach for accurately determining the dynamic properties of the samples is discussed.

  18. Electromagnetically Induced Transparency and Absorption of A Monochromatic Light Controlled by a Radio Frequency Field

    International Nuclear Information System (INIS)

    Cai Xun-Ming

    2015-01-01

    Electromagnetically induced transparency and absorption of a monochromatic light controlled by a radio frequency field in the cold multi-Zeeman-sublevel atoms are theoretically investigated. These Zeeman sublevels are coupled by a radio frequency (RF) field. Both electromagnetically induced transparency and electromagnetically induced absorption can be obtained by tuning the frequency of RF field for both the linear polarization and elliptical polarization monochromatic lights. When the transfer of coherence via spontaneous emission from the excited state to the ground state is considered, electromagnetically induced absorption can be changed into electromagnetically induced transparency with the change of intensity of radio field. The transparency windows controlled by the RF field can have potential applications in the magnetic-field measurement and quantum information processing. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  19. A code to determine the energy distribution, the incident energy and the flux of a beam of light ions into a stack of foils

    International Nuclear Information System (INIS)

    Sonzogni, A.A.; Romo, A.S.M.A.; Frosch, W.R.; Nassiff, S.J.

    1992-01-01

    The stacked-foil technique is one of the most used methods to obtain excitation functions of nuclear reactions using light ions as projectiles. The purpose of this program is the calculation of the energy of the beam in the stack, as well as to obtain the incident energy and the flux of the beam by using monitor excitation functions. (orig.)

  20. Photon polarization tensor in the light front field theory at zero and finite temperatures

    International Nuclear Information System (INIS)

    Silva, Charles da Rocha; Perez, Silvana; Strauss, Stefan

    2012-01-01

    Full text: In recent years, light front quantized field theories have been successfully generalized to finite temperature. The light front frame was introduced by Dirac , and the quantization of field theories on the null-plane has found applications in many branches of physics. In order to obtain the thermal contribution, we consider the hard thermal loop approximation. This technique was developed by Braaten and Pisarski for the thermal quantum field theory at equal times and is particularly useful to extract the leading thermal contributions to the amplitudes in perturbative quantum field theories. In this work, we consider the light front quantum electrodynamics in (3+1) dimensions and evaluate the photon polarization tensor at one loop for both zero and finite temperatures. In the first case, we apply the dimensional regularization method to extract the finite contribution and find the transverse structure for the amplitude in terms of the light front coordinates. The result agrees with one-loop covariant calculation. For the thermal corrections, we generalize the hard thermal loop approximation to the light front and calculate the dominant temperature contribution to the polarization tensor, consistent with the Ward identity. In both zero as well as finite temperature calculations, we use the oblique light front coordinates. (author)

  1. Method and apparatus for sensing a desired component of an incident magnetic field using magneto resistive elements biased in different directions

    Science.gov (United States)

    Pant, Bharat B. (Inventor); Wan, Hong (Inventor)

    1999-01-01

    A method and apparatus for sensing a desired component of a magnetic field using an isotropic magnetoresistive material. This is preferably accomplished by providing a bias field that is parallel to the desired component of the applied magnetic field. The bias field is applied in a first direction relative to a first set of magnetoresistive sensor elements, and in an opposite direction relative to a second set of magnetoresistive sensor elements. In this configuration, the desired component of the incident magnetic field adds to the bias field incident on the first set of magnetoresistive sensor elements, and subtracts from the bias field incident on the second set of magnetoresistive sensor elements. The magnetic field sensor may then sense the desired component of the incident magnetic field by simply sensing the difference in resistance of the first set of magnetoresistive sensor elements and the second set of magnetoresistive sensor elements.

  2. Magnetic-field-driven localization of light in a cold-atom gas.

    Science.gov (United States)

    Skipetrov, S E; Sokolov, I M

    2015-02-06

    We discover a transition from extended to localized quasimodes for light in a gas of immobile two-level atoms in a magnetic field. The transition takes place either upon increasing the number density of atoms in a strong field or upon increasing the field at a high enough density. It has many characteristic features of a disorder-driven (Anderson) transition but is strongly influenced by near-field interactions between atoms and the anisotropy of the atomic medium induced by the magnetic field.

  3. Double-layered liquid crystal light shutter for control of absorption and scattering of the light incident to a transparent display device

    Science.gov (United States)

    Huh, Jae-Won; Yu, Byeong-Hun; Shin, Dong-Myung; Yoon, Tae-Hoon

    2015-03-01

    Recently, a transparent display has got much attention as one of the next generation display devices. Especially, active studies on a transparent display using organic light-emitting diodes (OLEDs) are in progress. However, since it is not possible to obtain black color using a transparent OLED, it suffers from poor visibility. This inevitable problem can be solved by using a light shutter. Light shutter technology can be divided into two types; light absorption and scattering. However, a light shutter based on light absorption cannot block the background image perfectly and a light shutter based on light scattering cannot provide black color. In this work we demonstrate a light shutter using two liquid crystal (LC) layers, a light absorption layer and a light scattering layer. To realize a light absorption layer and a light scattering layer, we use the planar state of a dye-doped chiral nematic LC (CNLC) cell and the focal-conic state of a long-pitch CNLC cell, respectively. The proposed light shutter device can block the background image perfectly and show black color. We expect that the proposed light shutter can increase the visibility of a transparent display.

  4. Magnetic-field-dependent slow light in strontium atom-cavity system

    Science.gov (United States)

    Liu, Zeng-Xing; Wang, Bao; Kong, Cui; Xiong, Hao; Wu, Ying

    2018-03-01

    Realizing and controlling a long-lived slow light is of fundamental importance in physics and may find applications in quantum router and quantum information processing. In this work, we propose a feasible scheme to realize the slow light in a strontium atom-cavity system, in which the value of group delay can be continuously adjusted within a range of different Zeeman splittings and vacuum Rabi frequencies by varying the applied static magnetic field and the atom number instead of a strong coherent field. In our scheme, the major limitations of the slow-light structure, namely, dispersion and loss, can be effectively resolved, and so our scheme may help to achieve the practical application of slow light relevant to the optical communication network.

  5. Lighting

    Data.gov (United States)

    Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...

  6. Split-field FDTD method for oblique incidence study of periodic dispersive metallic structures.

    Science.gov (United States)

    Baida, F I; Belkhir, A

    2009-08-15

    The study of periodic structures illuminated by a normally incident plane wave is a simple task that can be numerically simulated by the finite-difference time-domain (FDTD) method. On the contrary, for off-normal incidence, a widely modified algorithm must be developed in order to bypass the frequency dependence appearing in the periodic boundary conditions. After recently implementing this FDTD algorithm for pure dielectric materials, we here extend it to the study of metallic structures where dispersion can be described by analytical models. The accuracy of our code is demonstrated through comparisons with already-published results in the case of 1D and 3D structures.

  7. On lamps, walls, and eyes: the spectral radiance field and the evaluation of light pollution indoors

    OpenAIRE

    Bará, Salvador; Escofet, Jaume

    2017-01-01

    Light plays a key role in the regulation of different physiological processes, through several visual and non-visual retinal phototransduction channels whose basic features are being unveiled by recent research. The growing body of evidence on the significance of these effects has sparked a renewed interest in the determination of the light field at the entrance pupil of the eye in indoor spaces. Since photic interactions are strongly wavelength-dependent, a significant effort is being devote...

  8. Effect of very high magnetic field on the optical properties of firefly light emitter oxyluciferin

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Weihang; Nakamura, Daisuke [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Wang, Yu [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences (China); Mochizuki, Toshimitsu [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, 2-2-9 Machiike-dai, Koriyama, Fukushima 963-0215 (Japan); Akiyama, Hidefumi [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Takeyama, Shojiro, E-mail: takeyama@issp.u-tokyo.ac.jp [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

    2015-09-15

    Magnetic field effect on enzymatic reactions is under intensive study in the past decades. Recently, it was reported that firefly bioluminescence was suppressed and red-shifted significantly when exposed to external magnetic field. However in this work, by means of selective excitation, we confirmed that emission properties of firefly light emitter “oxyluciferin” are completely immune to external magnetic field of up to 53 T. These findings pose strong contrast to existing relevant results. Potential reasons for the discrepancies found and the underlying physics towards the understanding of firefly bioluminescence were discussed. - Highlights: • Effect of ultra-high magnetic field on the optical properties of firefly light emitter oxyluciferin was reported. • Emission properties of oxyluciferin were confirmed to be immune to external high magnetic fields up to 53 T. • .Potential reasons for the discrepancies between our results and previous reports and the underlying physics were discussed.

  9. Phase microscopy using light-field reconstruction method for cell observation.

    Science.gov (United States)

    Xiu, Peng; Zhou, Xin; Kuang, Cuifang; Xu, Yingke; Liu, Xu

    2015-08-01

    The refractive index (RI) distribution can serve as a natural label for undyed cell imaging. However, the majority of images obtained through quantitative phase microscopy is integrated along the illumination angle and cannot reflect additional information about the refractive map on a certain plane. Herein, a light-field reconstruction method to image the RI map within a depth of 0.2 μm is proposed. It records quantitative phase-delay images using a four-step phase shifting method in different directions and then reconstructs a similar scattered light field for the refractive sample on the focus plane. It can image the RI of samples, transparent cell samples in particular, in a manner similar to the observation of scattering characteristics. The light-field reconstruction method is therefore a powerful tool for use in cytobiology studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. A 360-degree floating 3D display based on light field regeneration.

    Science.gov (United States)

    Xia, Xinxing; Liu, Xu; Li, Haifeng; Zheng, Zhenrong; Wang, Han; Peng, Yifan; Shen, Weidong

    2013-05-06

    Using light field reconstruction technique, we can display a floating 3D scene in the air, which is 360-degree surrounding viewable with correct occlusion effect. A high-frame-rate color projector and flat light field scanning screen are used in the system to create the light field of real 3D scene in the air above the spinning screen. The principle and display performance of this approach are investigated in this paper. The image synthesis method for all the surrounding viewpoints is analyzed, and the 3D spatial resolution and angular resolution of the common display zone are employed to evaluate display performance. The prototype is achieved and the real 3D color animation image has been presented vividly. The experimental results verified the representability of this method.

  11. Nanocrystalline silicon as the light emitting material of a field emission display device

    International Nuclear Information System (INIS)

    Biaggi-Labiosa, A; Sola, F; Resto, O; Fonseca, L F; Gonzalez-BerrIos, A; Jesus, J De; Morell, G

    2008-01-01

    A nanocrystalline Si-based paste was successfully tested as the light emitting material in a field emission display test device that employed a film of carbon nanofibers as the electron source. Stable emission in the 550-850 nm range was obtained at 16 V μm -1 . This relatively low field required for intense cathodoluminescence (CL) from the PSi paste may lead to longer term reliability of both the electron emitting and the light emitting materials, and to lower power consumption. Here we describe the synthesis, characterization, and analyses of the light emitting nanostructured Si paste and the electron emitting C nanofibers used for building the device, including x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The corresponding spectra and field emission curves are also shown and discussed

  12. Udder diseases in dairy cows — field observations on incidence, somatic and environmental factors, and control

    Directory of Open Access Journals (Sweden)

    Hannu Saloniemi

    1980-03-01

    Full Text Available The incidence of udder diseases and the predisposing factors were examined in 32 herds, in a total of 500 cows. During a 3-year-period 0.32 cases of clinical mastitis occurred per cow per annum. Subclinical mastitis was detected in 61.2 % of the cows during one year. The average incidence based on a single sampling was 36.5 %. In order to obtain reliable information on the udder health of a herd the occurrence of both clinical and subclinical mastitis must be followed. Clinical cases, both those treated by a veterinarian on a farm visit and those treated by the owner according to phone prescription must be filed statistically. In this study the incidence of mastitis as reported by owner was only half of that actually detected. The incidence of teat injuries requiring veterinary treatment was 0.03 cases per cow per annum. The diagnosis »presence of bacteria» obtained from a milk sample examination using Nordic methods means according to this study in most cases the probable occurrence of infection and mastitis. Scoring of observations made from udder health, and indexes based on these scores prove to be good tools when studying relationships between udder diseases and predisposing factors. Of the somatic factors the age of the cow, stage of lactation, the distance of the rear teats from the stall floor and the position of the teats influence the incidence of mastitis. Therefore, these factors must be taken into consideration in preventive work, especially in the culling of cows. Neither teat shape nor milkability had any connection with the incidence of udder diseases. With regard to the factors in the production environment the incidence of clinical mastitis was influenced especially by the function of the milking machine. Diurnal changes in temperature, when exceeding5 degrees centigrade, increased the occurrence of mastitis. The use of a thermohygrograph is proposed in preventive work. Because of the small number of the herds only in few

  13. Light

    DEFF Research Database (Denmark)

    Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

    2004-01-01

    This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

  14. Importance of holographic light in the emerging field of mind-body healing

    Science.gov (United States)

    Booth, Roberta

    2000-10-01

    Healing with color has been researched and documented worldwide for centuries. Every single part of the brain and every cell in the body is effected by light. Chinese and Russian scientists demonstrated that the acupuncture meridians transmit light. Dr. Peter Mandel, German chiropractic physician and acupuncturist, states that the acupuncture points are especially sensitive to electromagnetic waves within the spectrum of visible light and microwave energy, and all cells constantly emit and absorb small pockets of electromagnetic radiation or light, called biophotons. The harmony or disharmony of cells has been documented. Kirlian photography, to photography the aura was invented by Russians Semyon and Valentina Kirlian. Photo therapy and light research are being practiced worldwide. In the United States, Dr. Jacob Lieberman has written an influential book Light Medicine of the Future. In 1992 the first Light Years Ahead conference was held. (#5 1996) Dr. Brian Breiling and Dr. Lee Hartley brought together experts in the field to discuss the many potentials of light therapy. My present research in this area has focused on narrow band frequencies through the use of holography. Its therapeutic applications of color healing in this research are both critical and fundamental. My current work, The Chakras, seven reflection holograms on silver halide, relate to the wheels of light described in the earliest recorded Indian history. I will discus the chakras, this ancient metaphysical system under the new light of popular western metaphors and visionary art, how the chakras relate to the seven colors of the rainbow, the electromagnetic waves, and the connection to color holography in healing light therapy. I will be citing concurrent research in color healing, and the important areas of research that are necessary to have significant impact on future directions. Holography in the future will constitute a major frontier in discovery.

  15. Universal enveloping algebras of Toda field theories and the light-cone asymmetry parameter

    International Nuclear Information System (INIS)

    Itoyama, H.; Moxhay, P.

    1990-01-01

    The generators of the universal enveloping algebras in Toda field theories associated with Lie algebras are constructed. These form spectrum-generating algebras of the system which survive the constraints acting on the larger current algebra structure. It is found that the same generators fail to be a symmetry in the case of affine Toda field theory despite their close relationship with Mandelstam's soliton operators. We introduce the light-cone asymmetry parameter; its significance and utility are demonstrated. (orig.)

  16. Computational study of jet interaction flow field with and without incidence

    International Nuclear Information System (INIS)

    Asif, M.; Zahir, S.; Khan, M.A.

    2004-01-01

    The objective was to study the interaction of a side jet with the incoming supersonic flow and hypersonic flow. Qualitatively same Cp trends have been obtained as found experimentally. Also in aerodynamic coefficients side jet interaction results in additional pitching moment which is because of the high pressure region in upstream of the jet and a low pressure region in the downstream of the jet. Also jet interaction results in the rise in the lift coefficient. Whereas in the incidence case, simulation has been performed for the hypersonic flows over a biconic body with supersonic lateral jet at Mach 9.7 and incidence of 0 o to incidence of -12 o and 12 o . The results obtained were compared with the experimental and CFD code CFL3D results. PAK-3D over predicts the surface pressure as compared to the CFL3D and experimental results, whereas the qualitative trends are the same. Finally the integrated aerodynamic force coefficients were compared with CFL3D predicted results. (author)

  17. Deep inelastic lepton-nucleus scattering from the light-cone quantum field theory

    International Nuclear Information System (INIS)

    Boqiang Ma; Ji Sun

    1990-01-01

    We show that for deep inelastic lepton-nucleus scattering, the conditions which validate the impulse approximation are hardly satisfied when using ordinary instant form dynamics in the rest frame of the nucleus, whereas they are well satisfied when using instant form dynamics in the infinite-momentum frame, or using light-front form dynamics in an ordinary frame. Therefore a reliable theoretical treatment of deep inelastic lepton-nucleus scattering should be performed in the time-ordered perturbation theory in the infinite-momentum frame, or its equivalent, the light-cone perturbation theory in an ordinary frame. To this end, we extend the light-cone quantum field theory to the baryon-meson field to establish a relativistic composite model of nuclei. We then apply the impulse approximation to deep inelastic lepton-nucleus scattering in this model.(author)

  18. Quenching of light flickering in synthetic guanine crystals in aqueous solutions under strong static magnetic fields

    Science.gov (United States)

    Mootha, A.; Takanezawa, Y.; Iwasaka, M.

    2018-05-01

    The present study focused on the vibration of micro crystal particles of guanine due to Brownian motion. The organic particle has a refractive index of 1.83 and caused a flickering of light. To test the possibility of using magnetic properties under wet conditions, changes in the frequency of particle vibration by applying magnetic fields were investigated. At first, we found that the exposure at 5 T inhibited the flickering light intensities and the particle vibration slightly decreased. Next, we carried out a high speed camera measurement of the Brownian motion of the particle with a time resolution of 100 flame per second (fps) with and without magnetic field exposures. It was revealed that the vibrational speed of synthetic particles was enhanced at 500 mT. Detailed analyses of the particle vibration by changing the direction of magnetic fields versus the light source revealed that the Brownian motion's vibrational frequency was entrained under magnetic fields at 500 mT, and an increase in vibration speed to 20Hz was observed. Additional measurements of light scattering fluctuation using photo-detector and analyses on auto-correlation also confirmed this speculation. The studied Brownian vibration may be influenced by the change in mechanical interactions between the vibration particles and surrounding medium. The discovered phenomena can be applied for molecular and biological interactions in future studies.

  19. Light field intensification induced by nanoinclusions in optical thin-films

    International Nuclear Information System (INIS)

    Zhu Zhiwu; Cheng Xiangai; Huang Liangjin; Liu Zejin

    2012-01-01

    Inclusions even in tens of nanometers scale (nanoinclusion) can cause electric field intensifications locally in an optical thin-film when irradiated by laser. It was modeled by using finite element analysis, and the dependences of local light field on complex refractive index, diameter and embedded depth of the nanoinclusion were simulated. In addition, the average light intensity inside the nanodefect was calculated as well as the energy deposition rate. The modeling results show that extinction coefficient of a nanoinclusion has more significant effects on local light field than real part of the refractive index. A light intensification as large as 4× can occur owing to a metallic nanoinclusion and the peaks of electric field distribution locating on the boundary of the particulate. Energy deposition rate, reflecting the behavior of laser induced damage to the thin-film, is found to have the highest value at a certain extinction coefficient, instead of the state that, for a defect, a higher extinction coefficient causes a higher speed of laser absorption. And when this coefficient is relatively small, the energy deposition rate grows linearly with it. Finally, regarding high absorptive nanoinclusions, the larger can induce stronger laser intensification and higher average of energy deposition rate, whereas no significant difference is made by low absorptive nanoinclusions of different sizes.

  20. Light-induced space-charge fields for the structuration of dielectric materials

    International Nuclear Information System (INIS)

    Eggert, H.A.

    2006-11-01

    Light-induced space-charge fields in lithium-niobate crystals are used for patterning of dielectric materials. This includes tailored ferroelectric domains in the bulk of the crystal, different sorts of micro and nanoparticles on a crystal surface, as well as poling of electrooptic chromophores. A stochastical model is introduced, which can describe the spatial inhomogeneous domain inversion. (orig.)

  1. Photometric light curves for ten rapidly rotating stars in Alpha Persei, the Pleiades, and the field

    Science.gov (United States)

    Prosser, Charles F.; Schild, Rudolph E.; Stauffer, John R.; Jones, Burton F.

    1993-01-01

    We present the results from a photometric monitoring program of ten rapidly rotating stars observed during 1991 using the FLWO 48-in. telescope. Brightness variations for an additional six cluster stars observed with the Lick 40-in. telescope are also given. The periods and light curves for seven Alpha Persei members, two Pleiades members, and one naked T Tauri field star are reported.

  2. LFNet: A Novel Bidirectional Recurrent Convolutional Neural Network for Light-Field Image Super-Resolution.

    Science.gov (United States)

    Wang, Yunlong; Liu, Fei; Zhang, Kunbo; Hou, Guangqi; Sun, Zhenan; Tan, Tieniu

    2018-09-01

    The low spatial resolution of light-field image poses significant difficulties in exploiting its advantage. To mitigate the dependency of accurate depth or disparity information as priors for light-field image super-resolution, we propose an implicitly multi-scale fusion scheme to accumulate contextual information from multiple scales for super-resolution reconstruction. The implicitly multi-scale fusion scheme is then incorporated into bidirectional recurrent convolutional neural network, which aims to iteratively model spatial relations between horizontally or vertically adjacent sub-aperture images of light-field data. Within the network, the recurrent convolutions are modified to be more effective and flexible in modeling the spatial correlations between neighboring views. A horizontal sub-network and a vertical sub-network of the same network structure are ensembled for final outputs via stacked generalization. Experimental results on synthetic and real-world data sets demonstrate that the proposed method outperforms other state-of-the-art methods by a large margin in peak signal-to-noise ratio and gray-scale structural similarity indexes, which also achieves superior quality for human visual systems. Furthermore, the proposed method can enhance the performance of light field applications such as depth estimation.

  3. Formation of temperature fields in doped anisotropic crystals under spatially inhomogeneous light beams passing through them

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, E. V.; Markelov, A. S.; Trushin, V. N., E-mail: trushin@phys.unn.ru; Chuprunov, E. V. [Nizhni Novgorod State University (Russian Federation)

    2013-12-15

    The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.

  4. Near-field imaging of out-of-plane light scattering in photonic crystal slabs

    DEFF Research Database (Denmark)

    Volkov, Valentyn; Bozhevolnyi, Sergey; Taillaert, Dirk

    2003-01-01

    A collection scanning near-field optical microscope (SNOM) is used to image the propagating of light at telecommunication wavelengths (1520-1570 nm) along photonic crystal (PC) slabs, which combine slab waveguides with in-plane PCs consisting of one- and two-dimensional gratings. The efficient out...

  5. On lamps, walls, and eyes: The spectral radiance field and the evaluation of light pollution indoors

    Science.gov (United States)

    Bará, Salvador; Escofet, Jaume

    2018-01-01

    Light plays a key role in the regulation of different physiological processes, through several visual and non-visual retinal phototransduction channels whose basic features are being unveiled by recent research. The growing body of evidence on the significance of these effects has sparked a renewed interest in the determination of the light field at the entrance pupil of the eye in indoor spaces. Since photic interactions are strongly wavelength-dependent, a significant effort is being devoted to assess the relative merits of the spectra of the different types of light sources available for use at home and in the workplace. The spectral content of the light reaching the observer eyes in indoor spaces, however, does not depend exclusively on the sources: it is partially modulated by the spectral reflectance of the walls and surrounding surfaces, through the multiple reflections of the light beams along all possible paths from the source to the observer. This modulation can modify significantly the non-visual photic inputs that would be produced by the lamps alone, and opens the way for controlling-to a certain extent-the subject's exposure to different regions of the optical spectrum. In this work we evaluate the expected magnitude of this effect and we show that, for factorizable sources, the spectral modulation can be conveniently described in terms of a set of effective filter-like functions that provide useful insights for lighting design and light pollution assessment. The radiance field also provides a suitable bridge between indoor and outdoor light pollution studies.

  6. Incidence of viruses in fescue (Festuca sp.) seed production fields in the Willamette Valley in 2016

    Science.gov (United States)

    Tall Fescue seed production fields of Western Oregon were sampled and tested for the presence or absence of three viruses, Barley yellow dwarf virus (BYDV) -MAV and -PAV, and Cereal yellow dwarf virus (CYDV). There was no BYDV-MAV detected in any of the Fescue seed fields. The BYDV-PAV occurred in ...

  7. Orthogonal decomposition of a optical random field using a spatial modulator of light of liquid crystal

    International Nuclear Information System (INIS)

    Velez Juarez, Esteban; Rodriguez Garciapinna, Jorge L.; Ostrovsky, Andrey S.

    2016-01-01

    A technique for experimental determining the coherent-mode structure of electromagnetic field is proposed. This technique is based on the coherence measurements of the field in some reference basis and represents a nontrivial vector generalization of the dual-mode field correlation method recently reported by F. Ferreira and M. Belsley. The justifiability and efficiency of the proposed technique is illustrated by an example of determining the coherent-mode structure of some specially generated and experimentally characterized secondary electromagnetic source using a spatial modulator of light of liquid crystal (SLM-LC). (Author)

  8. A detailed comparison of single-camera light-field PIV and tomographic PIV

    Science.gov (United States)

    Shi, Shengxian; Ding, Junfei; Atkinson, Callum; Soria, Julio; New, T. H.

    2018-03-01

    This paper conducts a comprehensive study between the single-camera light-field particle image velocimetry (LF-PIV) and the multi-camera tomographic particle image velocimetry (Tomo-PIV). Simulation studies were first performed using synthetic light-field and tomographic particle images, which extensively examine the difference between these two techniques by varying key parameters such as pixel to microlens ratio (PMR), light-field camera Tomo-camera pixel ratio (LTPR), particle seeding density and tomographic camera number. Simulation results indicate that the single LF-PIV can achieve accuracy consistent with that of multi-camera Tomo-PIV, but requires the use of overall greater number of pixels. Experimental studies were then conducted by simultaneously measuring low-speed jet flow with single-camera LF-PIV and four-camera Tomo-PIV systems. Experiments confirm that given a sufficiently high pixel resolution, a single-camera LF-PIV system can indeed deliver volumetric velocity field measurements for an equivalent field of view with a spatial resolution commensurate with those of multi-camera Tomo-PIV system, enabling accurate 3D measurements in applications where optical access is limited.

  9. Inverse Doppler shift and control field as coherence generators for the stability in superluminal light

    Science.gov (United States)

    Ghafoor, Fazal; Bacha, Bakht Amin; Khan, Salman

    2015-05-01

    A gain-based four-level atomic medium for the stability in superluminal light propagation using control field and inverse Doppler shift as coherence generators is studied. In regimes of weak and strong control field, a broadband and multiple controllable transparency windows are, respectively, identified with significantly enhanced group indices. The observed Doppler effect for the class of high atomic velocity of the medium is counterintuitive in comparison to the effect of the class of low atomic velocity. The intensity of each of the two pump fields is kept less than the optimum limit reported in [M. D. Stenner and D. J. Gauthier, Phys. Rev. A 67, 063801 (2003), 10.1103/PhysRevA.67.063801] for stability in the superluminal light pulse. Consequently, superluminal stable domains with the generated coherence are explored.

  10. The incidence of breast cancer following mantle field radiation therapy as a function of dose and technique

    International Nuclear Information System (INIS)

    Tinger, Alfred; Wasserman, Todd H.; Klein, Eric E.; Miller, Elizabeth A.; Roberts, Tracy; Piephoff, James V.; Kucik, Nancy A.

    1997-01-01

    Purpose: There is an increased incidence of breast cancer following mantle field radiation therapy for Hodgkin's disease (HD). We reviewed the experience at the Mallinckrodt Institute of Radiology (MIR) for radiation factors related to the development of breast cancer after mantle field radiation therapy for HD. Methods: The radiation therapy records of 152 women treated with mantle field irradiation for HD at MIR between 1966-1985 were reviewed for the development of breast cancer and treatment-related factors. All patients had a minimum of 5 years of follow-up. The treatment era (1966-1974 vs. 1975-1985), stage of HD, mediastinal dose, axillary dose, maximum dose from the anterior field (anterior d max dose), the anterior-posterior:posterior-anterior (AP:PA) ratio, age at the time of treatment, length of follow-up, and history of splenectomy were analyzed as possible contributing factors for the development of breast cancer. The observed number of breast cancers was compared to the expected number based on age-adjusted incidences from the Connecticut Tumor Registry. Results: Ten breast cancers occurred in the population. Eight involved an upper outer quadrant. In a multivariate analysis, the development of breast cancer was significantly associated with axillary dose. Patients in the early treatment era were at an increased risk for the development of breast cancer due to high anterior d max and breast doses from weighting the fields anteriorly on a low energy linear accelerator. The use of current radiation therapy techniques was not related to an increased risk of breast cancer with a median follow-up of 13 years. Conclusions: A high dose to the axilla and the anterior d max point is significantly associated with the development of breast cancer after mantle field irradiation for HD. Efforts to protect the breast from high doses will likely lessen the increased risk of breast cancer in women treated with radiation therapy for HD

  11. Hard Thermal Loop approximation in the Light Front Quantum Field Theory

    International Nuclear Information System (INIS)

    Silva, Charles da Rocha; Perez, Silvana

    2011-01-01

    Full text: In this paper we generalize the Hard Thermal Loop approximation (HTL) for the Thermal Light Front Quantum Field Theory. This technique was developed by Braaten e Pisarski [PRL. 63 (1989) 1129, Nucl. Phys. B337 (1990) 569], for the Thermal Quantum Field Theory at equal time and is particularly useful to solve problems of convergence of the amplitudes within Quantum Chromodynamics, caused by the inherently nonperturbative behavior. The HTL approximation satisfies simple Ward identities, is ultraviolet finite and gauge independent. Here we use the light front generalized coordinates (GLFC) proposed by one of us (V. S. Alves, Ashok Das, e Silvana Perez [PRD. 66, (2002) 125008]) and analyze the one loop amplitudes for the λφ3 theory and the Quantum Electrodynamics in (3+1) dimensions at finite temperature in the HTL approximation. For the scalar theory, we evaluate the two-point function, recovering the usual dispersion relations. We also analyze the rotational invariance of the model. We then consider the Quantum Electrodynamics in (3+1) dimensions and calculate the polarization tensor and the vertex function at finite temperature in the HTL approximation. In future, our interest will be to apply the Generalized Light Front formalism to understand the confinement mechanism which occurs in the Quantum Chromodynamics. There is an expectation that the Light Front Quantum Field Theory formalism is more appropriate to study this problems. (author)

  12. Hard Thermal Loop approximation in the Light Front Quantum Field Theory

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Charles da Rocha [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Belem, PA (Brazil); Universidade Federal do Para (UFPA), Belem, PA (Brazil); Perez, Silvana [Universidade Federal do Para (UFPA), Belem, PA (Brazil)

    2011-07-01

    Full text: In this paper we generalize the Hard Thermal Loop approximation (HTL) for the Thermal Light Front Quantum Field Theory. This technique was developed by Braaten e Pisarski [PRL. 63 (1989) 1129, Nucl. Phys. B337 (1990) 569], for the Thermal Quantum Field Theory at equal time and is particularly useful to solve problems of convergence of the amplitudes within Quantum Chromodynamics, caused by the inherently nonperturbative behavior. The HTL approximation satisfies simple Ward identities, is ultraviolet finite and gauge independent. Here we use the light front generalized coordinates (GLFC) proposed by one of us (V. S. Alves, Ashok Das, e Silvana Perez [PRD. 66, (2002) 125008]) and analyze the one loop amplitudes for the {lambda}{phi}3 theory and the Quantum Electrodynamics in (3+1) dimensions at finite temperature in the HTL approximation. For the scalar theory, we evaluate the two-point function, recovering the usual dispersion relations. We also analyze the rotational invariance of the model. We then consider the Quantum Electrodynamics in (3+1) dimensions and calculate the polarization tensor and the vertex function at finite temperature in the HTL approximation. In future, our interest will be to apply the Generalized Light Front formalism to understand the confinement mechanism which occurs in the Quantum Chromodynamics. There is an expectation that the Light Front Quantum Field Theory formalism is more appropriate to study this problems. (author)

  13. A Comparison Between Magnetic Field Effects in Excitonic and Exciplex Organic Light-Emitting Diodes

    Science.gov (United States)

    Sahin Tiras, Kevser; Wang, Yifei; Harmon, Nicholas J.; Wohlgenannt, Markus; Flatte, Michael E.

    In flat-panel displays and lighting applications, organic light emitting diodes (OLEDs) have been widely used because of their efficient light emission, low-cost manufacturing and flexibility. The electrons and holes injected from the anode and cathode, respectively, form a tightly bound exciton as they meet at a molecule in organic layer. Excitons occur as spin singlets or triplets and the ratio between singlet and triplet excitons formed is 1:3 based on spin degeneracy. The internal quantum efficiency (IQE) of fluorescent-based OLEDs is limited 25% because only singlet excitons contribute the light emission. To overcome this limitation, thermally activated delayed fluorescent (TADF) materials have been introduced in the field of OLEDs. The exchange splitting between the singlet and triplet states of two-component exciplex systems is comparable to the thermal energy in TADF materials, whereas it is usually much larger in excitons. Reverse intersystem crossing occurs from triplet to singlet exciplex state, and this improves the IQE. An applied small magnetic field can change the spin dynamics of recombination in TADF blends. In this study, magnetic field effects on both excitonic and exciplex OLEDs will be presented and comparison similarities and differences will be made.

  14. Diffraction of ultracold fermions by quantized light fields: Standing versus traveling waves

    International Nuclear Information System (INIS)

    Meiser, D.; Search, C.P.; Meystre, P.

    2005-01-01

    We study the diffraction of quantum-degenerate fermionic atoms off of quantized light fields in an optical cavity. We compare the case of a linear cavity with standing-wave modes to that of a ring cavity with two counterpropagating traveling wave modes. It is found that the dynamics of the atoms strongly depends on the quantization procedure for the cavity field. For standing waves, no correlations develop between the cavity field and the atoms. Consequently, standing-wave Fock states yield the same results as a classical standing wave field while coherent states give rise to a collapse and revivals in the scattering of the atoms. In contrast, for traveling waves the scattering results in quantum entanglement of the radiation field and the atoms. This leads to a collapse and revival of the scattering probability even for Fock states. The Pauli exclusion principle manifests itself as an additional dephasing of the scattering probability

  15. Smart Fluid System Dually Responsive to Light and Electric Fields: An Electrophotorheological Fluid.

    Science.gov (United States)

    Yoon, Chang-Min; Jang, Yoonsun; Noh, Jungchul; Kim, Jungwon; Jang, Jyongsik

    2017-10-24

    Electrophotorheological (EPR) fluids, whose rheological activity is dually responsive to light and electric fields (E fields), is formulated by mixing photosensitive spiropyran-decorated silica (SP-sSiO 2 ) nanoparticles with zwitterionic lecithin and mineral oil. A reversible photorheological (PR) activity of the EPR fluid is developed via the binding and releasing mechanism of lecithin and merocyanine (MC, a photoisomerized form of SP) under ultraviolet (UV) and visible (VIS) light applications. Moreover, the EPR fluid exhibits an 8-fold higher electrorheological (ER) performance compared to the SP-sSiO 2 nanoparticle-based ER fluid (without lecithin) under an E field, which is attributed to the enhanced dielectric properties facilitated by the binding of the lecithin and SP molecules. Upon dual application of UV light and an E field, the EPR fluid exhibits high EPR performance (ca. 115.3 Pa) that far exceeds its separate PR (ca. 0.8 Pa) and ER (ca. 57.5 Pa) activities, because of the synergistic contributions of the PR and ER effects through rigid and fully connected fibril-like structures. Consequently, this study offers a strategy on formulation of dual-stimuli responsive smart fluid systems.

  16. Light radiation through a transparent cathode plate with single-walled carbon nanotube field emitters

    International Nuclear Information System (INIS)

    Jang, E.S.; Goak, J.C.; Lee, H.S.; Lee, S.H.; Han, J.H.; Lee, C.S.; Sok, J.H.; Seo, Y.H.; Park, K.S.; Lee, N.S.

    2010-01-01

    In the conventional carbon nanotube backlight units (CNT-BLUs), light passes through the phosphor-coated anode glass plate, which thus faces closely the thin film transistor (TFT) backplate of a liquid crystal display panel. This configuration makes heat dissipation structurally difficult because light emission and heat generation occur simultaneously at the anode. We propose a novel configuration of a CNT-BLU where the cathode rather than the anode faces the TFT backplate by turning it upside down. In this design, light passes through the transparent cathode glass plate while heating occurs at the anode. We demonstrated a novel design of CNT-BLU by fabricating transparent single-walled CNT field emitters on the cathode and by coating a reflecting metal layer on the anode. This study hopefully provides a clue to solve the anode-heating problem which would be inevitably confronted for high-luminance and large-area CNT-BLUs.

  17. Virus incidence in orchardgrass (Dactylis glomerata L.) seed production fields in the Willamette Valley

    Science.gov (United States)

    A survey was conducted over the course of three years (2014-2016) for the presence of Barley yellow dwarf virus (BYDV-MAV and BYDV-PAV), Cereal yellow dwarf virus (CYDV-RPV), and Cocksfoot mottle virus (CfMV) in orchardgrass (Dactylis glomerata) fields in the Willamette Valley, Oregon. There was an ...

  18. Relationships between Fusarium population structure, soil nutrient status and disease incidence in field-grown asparagus

    NARCIS (Netherlands)

    Yergeau, E.; Sommerville, D.W.; Maheux, E.; Vujanovic, V.; Hamel, C.; Whalen, J.K.; St-Arnaud, M.

    2006-01-01

    Fusarium species cause important diseases in many crops. Lack of knowledge on how Fusarium species and strains interact with their environment hampers growth management strategies to control root diseases. A field experiment involving asparagus as host plant and three phosphorus fertilization levels

  19. A spatial ecology study on the effects of field conditions and crop rotation on the incidence of Plectris aliena (Coleoptera: Scarabaeidae) grub damage to sweetpotato roots.

    Science.gov (United States)

    Brill, Nancy L; Osborne, Jason; Abney, Mark R

    2013-10-01

    A farmscape study was conducted in commercial sweetpotato (Ipomoea batatas (L.) Lam) fields in Columbus County, NC, in 2010 and 2011 to investigate the effects of the following field conditions: soil drainage class, soil texture, field size, border habitat, land elevation, and the previous year's crop rotation on the incidence of damage caused by Plectris aliena Chapman (Coleoptera:Scarabaeidae) larval feeding. Soil drainage and crop rotation significantly affected the incidence of damage to roots, with well drained soils having a low estimated incidence of damaged roots (0.004) compared with all other drainage classes (0.009-0.011 incidence of damaged roots). Fields with soybeans [Glycine max (L.) Merr] planted the preceding year had the highest incidence of root damage (0.15) compared with all other crops. The effects of border habitats, which were adjacent to grower fields where roots were sampled, showed that as the location of the roots was closer to borders of soybean (planted the year before) or grass fields, the chance of damage to roots decreased. Results indicate that growers can use crop rotation as a management technique and avoid planting sweetpotatoes the year after soybeans to reduce the incidence of P. aliena larval feeding on sweetpotato roots. Environmental conditions such as fields with poor drainage and certain border habitats may be avoided, or selected, by growers to reduce risk of damage to roots by P. aliena.

  20. Ab initio Hamiltonian approach to light nuclei and quantum field theory

    International Nuclear Information System (INIS)

    Vary, James P.

    2009-01-01

    A basis-function approach that has proven successful for solving the nonrelativistic strongly interacting nuclear many-body problem and appears promising for solving relativistic field theory in a light-front Hamiltonian framework is presented. Both conventional nuclear manybody theory and light-front field theory face common issues within the Hamiltonian approach - i.e. how to; (1) define the Hamiltonian; (2) renormalize to a finite space; (3) solve for non-perturbative observables, preserving as many symmetries as possible; and (4) take the continuum limit. Each of these challenges requires a substantial undertaking but appears solvable. Advances in computational physics, both algorithms and parallel computers, have proven essential to the recent progress. I will present results that illustrate the recent advances and indicate the path forward to ever more realistic applications

  1. Near-field Light Scattering Techniques for Measuring Nanoparticle-Surface Interaction Energies and Forces.

    Science.gov (United States)

    Schein, Perry; Ashcroft, Colby K; O'Dell, Dakota; Adam, Ian S; DiPaolo, Brian; Sabharwal, Manit; Shi, Ce; Hart, Robert; Earhart, Christopher; Erickson, David

    2015-08-15

    Nanoparticles are quickly becoming commonplace in many commercial and industrial products, ranging from cosmetics to pharmaceuticals to medical diagnostics. Predicting the stability of the engineered nanoparticles within these products a priori remains an important and difficult challenge. Here we describe our techniques for measuring the mechanical interactions between nanoparticles and surfaces using near-field light scattering. Particle-surface interfacial forces are measured by optically "pushing" a particle against a reference surface and observing its motion using scattered near-field light. Unlike atomic force microscopy, this technique is not limited by thermal noise, but instead takes advantage of it. The integrated waveguide and microfluidic architecture allow for high-throughput measurements of about 1000 particles per hour. We characterize the reproducibility of and experimental uncertainty in the measurements made using the NanoTweezer surface instrument. We report surface interaction studies on gold nanoparticles with 50 nm diameters, smaller than previously reported in the literature using similar techniques.

  2. A method for the real-time construction of a full parallax light field

    Science.gov (United States)

    Tanaka, Kenji; Aoki, Soko

    2006-02-01

    We designed and implemented a light field acquisition and reproduction system for dynamic objects called LiveDimension, which serves as a 3D live video system for multiple viewers. The acquisition unit consists of circularly arranged NTSC cameras surrounding an object. The display consists of circularly arranged projectors and a rotating screen. The projectors are constantly projecting images captured by the corresponding cameras onto the screen. The screen rotates around an in-plane vertical axis at a sufficient speed so that it faces each of the projectors in sequence. Since the Lambertian surfaces of the screens are covered by light-collimating plastic films with vertical louver patterns that are used for the selection of appropriate light rays, viewers can only observe images from a projector located in the same direction as the viewer. Thus, the dynamic view of an object is dependent on the viewer's head position. We evaluated the system by projecting both objects and human figures and confirmed that the entire system can reproduce light fields with a horizontal parallax to display video sequences of 430x770 pixels at a frame rate of 45 fps. Applications of this system include product design reviews, sales promotion, art exhibits, fashion shows, and sports training with form checking.

  3. Discrete gravity as a topological field theorywith light-like curvature defects

    Energy Technology Data Exchange (ETDEWEB)

    Wieland, Wolfgang [Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada)

    2017-05-29

    I present a model of discrete gravity as a topological field theory with defects. The theory has no local degrees of freedom and the gravitational field is trivial everywhere except at a number of intersecting null surfaces. At these null surfaces, the gravitational field can be singular, representing a curvature defect propagating at the speed of light. The underlying action is local and it is studied in both its Lagrangian and Hamiltonian formulation. The canonically conjugate variables on the null surfaces are a spinor and a spinor-valued two-surface density, which are coupled to a topological field theory for the Lorentz connection in the bulk. I discuss the relevance of the model for non-perturbative approaches to quantum gravity, such as loop quantum gravity, where similar variables have recently appeared as well.

  4. Effects of light guide and magnetic field on the characteristics of the short time measuring system

    International Nuclear Information System (INIS)

    Yamada, Yoshihiro; Ohira, Kyozo

    1977-01-01

    In order to construct the nuclear life-time measurement apparatus with good energy and time resolution, consisting of DuMond type beta-ray spectrometer and plastic scintillator, experimental studies are carried out for the effects of light guide and magnetic field on the time resolution, and for the effects of μ-metal shielding on the energy resolution. It has been found that all these effects could be practically diminished. (auth.)

  5. Near-field imaging of light propagation in photonic crystal waveguides: Explicit role of Bloch harmonics

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Volkov, V.S.; Søndergaard, Thomas

    2002-01-01

    We employ a collection scanning near-field optical microscope (SNOM) to image the propagation of light at telecommunication wavelengths along straight and bent regions of silicon-on-insulator photonic crystal waveguides (PCWs) formed by removing a single row of holes in the triangular 410-nm...... the interference between a quasihomogeneous background field and Bloch harmonics of the PCW mode, we account for spatial frequency spectra of the intensity variations and determine the propagation constant of the PCW mode at 1520 nm. The possibilities and limitations of SNOM imaging for the characterization...

  6. The effect of air flow, panel curvature, and internal pressurization on field-incidence transmission loss. [acoustic propagation through aircraft fuselage

    Science.gov (United States)

    Koval, L. R.

    1975-01-01

    In the context of sound transmission through aircraft fuselage panels, equations for the field-incidence transmission loss (TL) of a single-walled panel are derived that include the effects of external air flow, panel curvature, and internal fuselage pressurization. These effects are incorporated into the classical equations for the TL of single panels, and the resulting double integral for field-incidence TL is numerically evaluated for a specific set of parameters.

  7. SVBRDF-Invariant Shape and Reflectance Estimation from a Light-Field Camera.

    Science.gov (United States)

    Wang, Ting-Chun; Chandraker, Manmohan; Efros, Alexei A; Ramamoorthi, Ravi

    2018-03-01

    Light-field cameras have recently emerged as a powerful tool for one-shot passive 3D shape capture. However, obtaining the shape of glossy objects like metals or plastics remains challenging, since standard Lambertian cues like photo-consistency cannot be easily applied. In this paper, we derive a spatially-varying (SV)BRDF-invariant theory for recovering 3D shape and reflectance from light-field cameras. Our key theoretical insight is a novel analysis of diffuse plus single-lobe SVBRDFs under a light-field setup. We show that, although direct shape recovery is not possible, an equation relating depths and normals can still be derived. Using this equation, we then propose using a polynomial (quadratic) shape prior to resolve the shape ambiguity. Once shape is estimated, we also recover the reflectance. We present extensive synthetic data on the entire MERL BRDF dataset, as well as a number of real examples to validate the theory, where we simultaneously recover shape and BRDFs from a single image taken with a Lytro Illum camera.

  8. Light

    CERN Document Server

    Robertson, William C

    2003-01-01

    Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...

  9. Near-field diffraction of laser light by dielectric corner step

    Science.gov (United States)

    Stafeev, S.; Kotlyar, V.; Kovalev, A.

    2014-01-01

    The diffraction of a linearly polarized plane wave by a corner dielectric microstep of height equals of two incident wavelengths was studied using finite-difference time domain method and near-field scanning optical microscopy. It was shown that the corner step generates an elongated region of enhanced intensity, termed as a curved laser microjet. The curved laser microjet has a length of about DOF = 9.5λ and the smallest diameter FWHM = (1.94+/-0.15)λ at distance z = 5.5λ.

  10. Incidence of malignant lymphoma in adolescents and young adults in the 58 counties of California with varying synthetic turf field density.

    Science.gov (United States)

    Bleyer, Archie; Keegan, Theresa

    2018-04-01

    Case reports of cancer among soccer players raised concerns that the crumb rubber infill in synthetic turf fields may cause malignant lymphoma. One prior epidemiologic study on the topic found no association. An ecologic evaluation of county-level incidence of lymphomas by race/ethnicity and socioeconomic status for the state of California with data obtained from the National Cancer Institute Surveillance, Epidemiology, and End Results Program. Synthetic turf field density by county was obtained from the Synthetic Turf Council. During 2000-2013, 7214 14- to 30-year-old Californians were diagnosed with malignant lymphoma. Annual lymphoma county incidence trends were not associated with the county-level synthetic turf field density. None of 20 sub-analyses by race/ethnicity, sex and county median household income indicated a correlation of lymphoma incidence with synthetic turf field density. In California, there was no evidence at the county-level that synthetic turf fields are associated with an increased incidence of lymphoma in adolescents and young adults. Our findings in the state with the greatest number of such fields and a large, diverse patient population are consistent with those of a prior study observing no association between individual-level exposures to turf fields and cancer incidence. Avoidance of synthetic turf fields for fear of increased cancer risk is not warranted. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Red light sensitive heterojunction organic field-effect transistors based on neodymium phthalocyanine as photosensitive layer

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Wenli; Tang, Yu [Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, South Tianshui Road 222#, Lanzhou 730000 (China); Yao, Bo [Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, South Tianshui Road 222#, Lanzhou 730000 (China); Department of Physics, Shaoxing University, Shaoxing 312000 (China); Zhou, Maoqing; Luo, Xiao; Li, Yao; Zhong, Junkang; Sun, Lei [Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, South Tianshui Road 222#, Lanzhou 730000 (China); Peng, Yingquan, E-mail: yqpeng@lzu.edu.cn [Institute of Microelectronics, School of Physical Science and Technology, Lanzhou University, South Tianshui Road 222#, Lanzhou 730000 (China); Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, South Tianshui Road 222#, Lanzhou 730000 (China)

    2015-08-31

    Compared with organic photodiodes, photoresponsive organic field-effect transistors (photOFETs) exhibit higher sensitivity and lower noise. The performance of photOFETs based on conventional single layer structure is generally poor due to the low carrier mobility of the active channel materials. We demonstrate a high performance photOFET operating in red light with a structure of C60/neodymium phthalocyanine (NdPc{sub 2}) planar heterojunction. PhotOFETs based on single-layer NdPc{sub 2} and C60/NdPc{sub 2} heterojunction (denoted as NdPc{sub 2}-photOFETs and C60/NdPc{sub 2}-photOFETs, respectively) were fabricated and characterized. It is concluded that the photOFETs with heterojunction structure showed superior performance compared to that of single layer photOFETs. And for red light with a wavelength of 655 nm, C60/NdPc{sub 2}-photOFETs exhibited a large photoresponsivity of ~ 0.8 A/W, which is approximately 62 times larger than that of NdPc{sub 2}-photOFETs under the same conditions. The high performance of C60/NdPc{sub 2}-photOFETs is attributed to its high light absorption coefficient, high exciton dissociation efficiency and high carrier mobility. - Highlights: • The mobility of light-sensitive organic materials is generally low. • We fabricated C60/NdPc{sub 2} photoresponsive organic field-effect transistors (photOFETs). • The performance of C60/NdPc{sub 2} photOFETs is superior than single-layer NdPc{sub 2} photOFETs. • C60/NdPc{sub 2} photOFETs exhibited a large photoresponsivity of ~ 0.8 A/W for red light.

  12. Laboratory and field measurements of enantiomeric monoterpene emissions as a function of chemotype, light and temperature

    Science.gov (United States)

    Song, W.; Staudt, M.; Bourgeois, I.; Williams, J.

    2014-03-01

    Plants emit significant amounts of monoterpenes into the earth's atmosphere, where they react rapidly to form a multitude of gas phase species and particles. Many monoterpenes exist in mirror-image forms or enantiomers. In this study the enantiomeric monoterpene profile for several representative plants (Quercus ilex L., Rosmarinus officinalis L., and Pinus halepensis Mill.) was investigated as a function of chemotype, light and temperature both in the laboratory and in the field. Analysis of enantiomeric monoterpenes from 19 Quercus ilex individuals from Southern France and Spain revealed four regiospecific chemotypes (genetically fixed emission patterns). In agreement with previous work, only Quercus ilex emissions increased strongly with light. However, for all three plant species no consistent enantiomeric variation was observed as a function of light, and the enantiomeric ratio of α-pinene was found to vary by less than 20% from 100 and 1000 μmol m-2 s-1 PAR (photosynthetically active radiation). The rate of monoterpene emission increased with temperature from all three plant species, but little variation in the enantiomeric distribution of α-pinene was observed with temperature. There was more enantiomeric variability between individuals of the same species than could be induced by either light or temperature. Field measurements of α-pinene enantiomer mixing ratios in the air, taken at a Quercus ilex forest in Southern France, and several other previously reported field enantiomeric ratio diel cycle profiles are compared. All show smoothly varying diel cycles (some positive and some negative) even over changing wind directions. This is surprising in comparison with variations of enantiomeric emission patterns shown by individuals of the same species.

  13. Exploring the Impact of Natural Light Exposure on Sleep of Healthy Older Adults: A Field Study

    Directory of Open Access Journals (Sweden)

    Mariëlle P. J. Aarts

    2018-05-01

    Full Text Available Studies among people with dementia demonstrated that the sleep quality and rhythm improves significantly when people are exposed to ambient bright light. Since almost half of the healthy older people also indicate to suffer from chronic sleep disorders, the question arises whether ambient bright light can be beneficial to healthy older people. Particularly the effect on sleep/wake rhythm in relation to the exposure to natural light is the focus. It was hypothesised that the sleep quality would be worse in winter due to a lower daylight dose than in summer due to the lower illuminance and exposure duration. A field study was conducted to examine the relationship between daylight exposure and sleep quality in 14 healthy older adults living independently in their own dwellings in the Netherlands. All participants were asked to take part of the study both during the summer period as well as during the winter period. Therefore, they had to wear an actigraph for five consecutive days which measured sleep, activity and light exposure. Results confirmed that people were significantly longer exposed to high illumination levels (>1000 lx in summer than in winter. Sleep quality measures, however, did not differ significantly between summer and winter. A significant, positive correlation was found between exposure duration to high illuminance from daylight during the day and the sleep efficiency the following night in summer, implying that being exposed to high illuminance for a longer time period has a positive effect on sleep efficiency for the individual data. There was also a tendency of less frequent napping in case of longer exposure duration to light for both seasons. Sleep quality does not differ between summer and winter but is related to the duration of the exposure to bright light the day prior to the night.

  14. Incidence of 'Candidatus Liberibacter asiaticus'-Infected Plants Among Citrandarins as Rootstock and Scion Under Field Conditions.

    Science.gov (United States)

    Boava, Leonardo Pires; Sagawa, Cíntia Helena Duarte; Cristofani-Yaly, Mariângela; Machado, Marcos Antonio

    2015-04-01

    Huanglongbing (HLB), caused by the bacterium 'Candidatus Liberibacter' spp., is currently one of the most serious diseases of citrus plants and has caused substantial economic losses. Thus far, there is no source of genetic resistance to HLB in the genus Citrus or its relatives. However, several studies have reported Poncirus trifoliata and some of its hybrids to be more tolerant to the disease. The main objective of this study was to report differences in the incidence of 'Ca. L. asiaticus' infection in citrandarin plants, hybrids from Sunki mandarin (Citrus sunki (Hayata) hort. ex Tanaka), and trifoliate orange Rubidoux (P. trifoliata (L.) Raf.)), after conducting an extensive survey under field conditions. These hybrid plants were established for approximately 7 years in an area with a high incidence of 'Ca. L. asiaticus'-infected plants. We selected two experimental areas (area A and area B), located approximately 10 m apart. Area A consists of Pera sweet orange (C. sinensis (L.) Osb.) grafted onto 56 different citrandarin rootstocks. Area B consists of citrandarin scions grafted onto Rangpur lime (C. limonia Osb.) rootstock. Bacteria in the leaves and roots were detected using real-time quantitative polymerase chain reaction. The incidence of 'Ca. L. asiaticus'-infected plants was 92% in area A and 14% in area B. Because infected plants occurred in both areas, we examined whether the P. trifoliata hybrid rootstock influenced HLB development and also determined the distribution of 'Ca. L. asiaticus' in Citrus tree tissues. Although this survey does not present evidence regarding the resistance of P. trifoliata and its hybrids in relation to bacteria or psyllids, future investigation, mainly using the most promising hybrids for response to 'Ca. L. asiaticus', will help us to understand the probable mechanism of defense or identifying compounds in P. trifoliata and its hybrids that are very important as strategy to combat HLB. Details of these results are

  15. Automated measurement of spatial preference in the open field test with transmitted lighting.

    Science.gov (United States)

    Kulikov, Alexander V; Tikhonova, Maria A; Kulikov, Victor A

    2008-05-30

    New modification of the open field was designed to improve automation of the test. The main innovations were: (1) transmitted lighting and (2) estimation of probability to find pixels associated with an animal in the selected region of arena as an objective index of spatial preference. Transmitted (inverted) lighting significantly ameliorated the contrast between an animal and arena and allowed to track white animals with similar efficacy as colored ones. Probability as a measure of preference of selected region was mathematically proved and experimentally verified. A good correlation between probability and classic indices of spatial preference (number of region entries and time spent therein) was shown. The algorithm of calculation of probability to find pixels associated with an animal in the selected region was implemented in the EthoStudio software. Significant interstrain differences in locomotion and the central zone preference (index of anxiety) were shown using the inverted lighting and the EthoStudio software in mice of six inbred strains. The effects of arena shape (circle or square) and a novel object presence in the center of arena on the open field behavior in mice were studied.

  16. Incidence of micronuclei in human peripheral blood lymphocytes exposed to modulated and unmodulated 2450 MHz radiofrequency fields.

    Science.gov (United States)

    Vijayalaxmi; Reddy, Abhishek B; McKenzie, Raymond J; McIntosh, Robert L; Prihoda, Thomas J; Wood, Andrew W

    2013-10-01

    Peripheral blood samples from four healthy volunteers were collected and aliquots were exposed in vitro for 2 h to either (i) modulated (wideband code division multiple access, WCDMA) or unmodulated continuous wave (CW) 2450 MHz radiofrequency (RF) fields at an average specific absorption rate of 10.9 W/kg or (ii) sham-exposed. Aliquots of the same samples that were exposed in vitro to an acute dose of 1.5 Gy ionizing gamma-radiation (GR) were used as positive controls. Half of the aliquots were treated with melatonin (Mel) to investigate if such treatment offers protection to the cells from the genetic damage, if any, induced by RF and GR. The cells in all samples were cultured for 72 h and the lymphocytes were examined to determine the extent of genetic damage assessed from the incidence of micronuclei (MN). The results indicated the following: (i) the incidence of MN was similar in incubator controls, and those exposed to RF/sham and Mel alone; (ii) there were no significant differences between WCDMA and CW RF exposures; (iii) positive control cells exposed to GR alone exhibited significantly increased MN; and (iv) Mel treatment had no effect on cells exposed to RF and sham, while such treatment significantly reduced the frequency of MN in GR-exposed cells. Copyright © 2013 Wiley Periodicals, Inc.

  17. Light-pressure-induced nonlinear dispersion of a laser field interacting with an atomic gas

    International Nuclear Information System (INIS)

    Grimm, R.; Mlynek, J.

    1990-01-01

    We report on detailed studies of the effect of resonant light pressure on the optical response of an atomic gas to a single monochromatic laser field. In this very elementary situation of laser spectroscopy, the redistribution of atomic velocities that is induced by spontaneous light pressure leads to a novel contribution to the optical dispersion curve of the medium. This light-pressure-induced dispersion phenomenon displays a pronounced nonlinear dependence on the laser intensity. Moreover, for a given intensity, its strength is closely related to the laser beam diameter. As most important feature, this light-pressure-induced dispersion displays an even symmetry with respect to the optical detuning from line center. As a result, the total Doppler-broadened dispersion curve of the gas can become asymmetric, and a significant shift of the dispersion line center can occur. In addition to a detailed theoretical description of the phenomenon, we report on its experimental investigation on the λ=555.6 nm 1 S 0 - 3 P 1 transition in atomic ytterbium vapor with the use of frequency-modulation spectroscopy. The experimental findings are in good quantitative agreement with theoretical predictions

  18. SOUND TRANSMISSION LOSS OF A DOUBLE-LEAF PARTITION WITH MICRO-PERFORATED PLATE INSERTION UNDER DIFFUSE FIELD INCIDENCE

    Directory of Open Access Journals (Sweden)

    A. Putra

    2013-06-01

    Full Text Available In noise control applications, a double-leaf partition has been applied widely as a lightweight structure for noise insulation, such as in car doors, train bodies, and aircraft fuselages. Unfortunately, the insulation performance deteriorates significantly at mass-air-mass resonance due to coupling between the panels and the air in the gap. This paper investigates the effect of a micro-perforated panel (MPP, inserted in the conventional double-panel partition, on sound transmission loss at troublesome resonant frequencies. It is found that the transmission loss improves at this resonance if the MPP is located at a distance of less than half that of the air gap. A mathematical model is derived for the diffuse field incidence of acoustic loading.

  19. Response of the 'patient dose calibrator' chamber for incident positions and sizes of X-ray fields

    International Nuclear Information System (INIS)

    Oliveira, Cassio M.; Abrantes, Marcos Eugenio S.; Ferreira, Flavia C. Bastos; Lacerda, Marco A. de Souza; Alonso, Thessa C.; Silva, Teogenes A. da; Oliveira, Paulo Marcio C.

    2009-01-01

    The evaluation of patient doses is an important tool for optimizing radiodiagnostic medical procedures with conventional X-ray equipment and for improving the quality of the radiographic image. The Patient Dose Calibrator (PDC) chamber is a dosimetric instrument that is used in the evaluation of the air kerma-area product (P KA ) quantity aiming the reduction of patient doses. The objective this work was to study the P KA variation caused by different field incident positions and sizes of the X-ray beam on the PDC chamber. Results showed that the PDC chamber has repeatability lower than 0.6%, beam position dependence of 3% and linearity response within ± 6%; these characteristics are to be taken into account during evaluation of the radiological protection conditions of conventional x-ray equipment. (author)

  20. Light

    CERN Document Server

    Ditchburn, R W

    1963-01-01

    This classic study, available for the first time in paperback, clearly demonstrates how quantum theory is a natural development of wave theory, and how these two theories, once thought to be irreconcilable, together comprise a single valid theory of light. Aimed at students with an intermediate-level knowledge of physics, the book first offers a historical introduction to the subject, then covers topics such as wave theory, interference, diffraction, Huygens' Principle, Fermat's Principle, and the accuracy of optical measurements. Additional topics include the velocity of light, relativistic o

  1. Illuminating the hidden sector of string theory by shining light through a magnetic field

    International Nuclear Information System (INIS)

    Abel, S.A.; Khoze, V.V.

    2006-08-01

    It has recently been shown that the observation by the PVLAS collaboration of an anomalously large rotation of the polarization plane of light in the presence of a magnetic field in vacuum may originate from pair production of light, m f ∝0.1 eV, millicharged, Q f ∝3 x 10 -6 e, fermions. Such millicharges arise generically from kinetic-mixing in theories containing at least two U(1) gauge factors. In this letter, we point out that the required multiple U(1) factors, the size of kinetic-mixing, and suitable matter representations to explain the PVLAS data occur very naturally in the context of realistic extensions of the Standard Model (SM) of elementary particle physics based on string theory. (orig.)

  2. Coherent scattering of three-level atoms in the field of a bichromatic standing light wave

    International Nuclear Information System (INIS)

    Pazgalev, A.S.; Rozhdestvenskii, Yu.V.

    1996-01-01

    We discuss the coherent scattering of three-level atoms in the field of two standing light waves for two values of the spatial shift. In the case of a zero spatial shift and equal frequency detunings of the standing waves, the problem of scattering of a three-level atoms is reduced to scattering of an effectively two-level atom. For the case of an exact resonance between the waves and transitions we give expressions for the population probability of the states of the three-level atom obtained in the short-interaction-time approximation. Depending on the initial population distribution over the states, different scattering modes are realized. In particular, we show that there can be initial conditions for which the three-level system does not interact with the field of the standing waves, with the result that there is no coherent scattering of atoms. In the case of standing waves shifted by π/2, there are two types of solution, depending on the values of the frequency detuning. For instance, when the light waves are detuned equally we give the exact solution for arbitrary relationships between the detuning and the standing wave intensities valid for any atom-field interaction times. The case of 'mirror' detunings and shifted standing waves is studied only numerically

  3. THE EFFECT OF MAGNETIC FIELD ON THE EFFICIENCY OF A SILICON SOLAR CELL UNDER AN INTENSE LIGHT CONCENTRATION

    Directory of Open Access Journals (Sweden)

    Zoungrana Martial

    2017-06-01

    Full Text Available This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cell illuminated by an intense light concentration: external load electric power, conversion efficiency, fill factor, external optimal charge load. Due to the high photogeneration of carrier in intense light illumination mode, in addition of magnetic field, we took into account the carrier gradient electric field in the base of the solar cell. Taking into account this electric field and the applied magnetic field in our model led to new analytical expressions of the continuity equation, the photocurrent and the photovoltage.

  4. Understanding the Role of Critical Incidents in Relation to Self-Efficacy during Course-Embedded Preservice Teacher Field Experiences: A Qualitative Study

    Science.gov (United States)

    Epperly, Anna C.

    2017-01-01

    This qualitative, collective case study documented the development of the self-efficacy beliefs of special education preservice candidates during one semester of a course-embedded field experience in a small, private, faith-based university in the Midwest. Interviews of candidates regarding critical incidents in field experiences as documented by…

  5. Optical design and development of a snapshot light-field laryngoscope

    Science.gov (United States)

    Zhu, Shuaishuai; Jin, Peng; Liang, Rongguang; Gao, Liang

    2018-02-01

    The convergence of recent advances in optical fabrication and digital processing yields a generation of imaging technology-light-field (LF) cameras which bridge the realms of applied mathematics, optics, and high-performance computing. Herein for the first time, we introduce the paradigm of LF imaging into laryngoscopy. The resultant probe can image the three-dimensional shape of vocal folds within a single camera exposure. Furthermore, to improve the spatial resolution, we developed an image fusion algorithm, providing a simple solution to a long-standing problem in LF imaging.

  6. Atomic wavefunctions probed through strong-field light-matter interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mairesse, Y; Villeneuve, D M; Corkum, P B; Dudovich, N [Natl Res Council Canada, Ottawa, ON K1A 0R6 (Canada); Shafir, D; Dudovich, N [Weizmann Inst Sci, Dept Phys Complex Syst, IL-76100 Rehovot, (Israel); Mairesse, Y [Univ Bordeaux 1, CELIA, CNRS, UMR 5107, CEA, F-33405 Talence (France)

    2009-07-01

    Strong-field light-matter interactions can encode the spatial properties of the electronic wavefunctions that contribute to the process. In particular, the broadband harmonic spectra, measured for a series of molecular alignments, can be used to create a tomographic reconstruction of molecular orbitals. Here, we present an extension of the tomography approach to systems that cannot be naturally aligned. We demonstrate this ability by probing the two-dimensional properties of atomic wavefunctions. By manipulating an electron-ion re-collision process, we are able to resolve the symmetry of the atomic wavefunction with high contrast. (authors)

  7. Light absorption in disordered semiconductors with a random coulomb-type field

    International Nuclear Information System (INIS)

    Arbuzov, Yu.D.; Evdokimov, V.M.; Kolenkin, M.Yu.

    1988-01-01

    A method is proposed for the formulation of an asymptotic series for the light absorption coefficient in disordered semiconductors with a random field of the Coulomb type. It is shown that the series is obtained by expanding the exponent of an exponential function in powers of a parameter proportional to (E g - ℎω) -1/3 , where E g is the band gap of the semiconductor, and ℎω is the photon energy. The first three terms of the series are calculated in explicit form

  8. Collapse and Revival of an Atomic Beam Interacting with a Coherent State Light Field

    International Nuclear Information System (INIS)

    Ben, Li; Jing-Biao, Chen

    2009-01-01

    We report on the phenomena of the periodic spontaneous collapse and revival in the dynamics of an atomic beam interacting with a single-mode and coherent-state light field. Conventional collapse and revival by Eberly et al. [Phys. Rev. Lett. 44 (1980) 1323] are presented in the case of the evolution with time of the population inversion. Here, we study the evolution with coupling strength of population inversion. We define the collapse and revival coupling strengths as characteristic parameters to describe the above collapse and revival. Furthermore, we present the analytic formulas for the population inversion, the collapse and revival coupling strengths

  9. Uranium isotope separation by magnetic field gradient and visible light acting in a liquid medium

    International Nuclear Information System (INIS)

    Borges, O.N.

    1985-01-01

    The literature shows that excited uranyl can assume the ''singlet'' and ''triplet'' states, with different magnetic properties. In an aqueous medium, without organic complexity (to hamper dismutation), the action of light reduces uranyl to U(V), which is a radical -ion that can assume the ''doublet'' and ''quartet'' states, also with different magnetic properties. Due to the different constants of velocity of uranium 235 and 238 in the reduction of excited uranyl and in the oxidation of U(V) to UO 2 2+ , there is the probability of forming an isotopic gradient, in the aqueous solution, subjected to a magnetic field gradient, with consequent appropriate extraction. 6 refs

  10. Light up my day : a between-group test of dynamic lighting effects on office workers' wellbeing in the field

    NARCIS (Netherlands)

    Smolders, K.C.H.J.; Kort, de Y.A.W.; Yener, A.K.; Oztürk, L.D.

    2009-01-01

    Dynamic lighting is designed to have positive effects on wellbeing and performance. However, whether these effects are detectable and stable over time when employed in actual work settings has not been thoroughly investigated. We explore whether beneficial effects of dynamic lighting indeed hold up

  11. Quantitative and Isolated Measurement of Far-Field Light Scattering by a Single Nanostructure

    Science.gov (United States)

    Kim, Donghyeong; Jeong, Kwang-Yong; Kim, Jinhyung; Ee, Ho-Seok; Kang, Ju-Hyung; Park, Hong-Gyu; Seo, Min-Kyo

    2017-11-01

    Light scattering by nanostructures has facilitated research on various optical phenomena and applications by interfacing the near fields and free-propagating radiation. However, direct quantitative measurement of far-field scattering by a single nanostructure on the wavelength scale or less is highly challenging. Conventional back-focal-plane imaging covers only a limited solid angle determined by the numerical aperture of the objectives and suffers from optical aberration and distortion. Here, we present a quantitative measurement of the differential far-field scattering cross section of a single nanostructure over the full hemisphere. In goniometer-based far-field scanning with a high signal-to-noise ratio of approximately 27.4 dB, weak scattering signals are efficiently isolated and detected under total-internal-reflection illumination. Systematic measurements reveal that the total and differential scattering cross sections of a Au nanorod are determined by the plasmonic Fabry-Perot resonances and the phase-matching conditions to the free-propagating radiation, respectively. We believe that our angle-resolved far-field measurement scheme provides a way to investigate and evaluate the physical properties and performance of nano-optical materials and phenomena.

  12. eLISA Telescope In-field Pointing and Scattered Light Study

    Science.gov (United States)

    Livas, J.; Sankar, S.; West, G.; Seals, L.; Howard, J.; Fitzsimons, E.

    2017-05-01

    The orbital motion of the three spacecraft that make up the eLISA Observatory constellation causes long-arm line of sight variations of approximately ± one degree over the course of a year. The baseline solution is to package the telescope, the optical bench, and the gravitational reference sensor (GRS) into an optical assembly at each end of the measurement arm, and then to articulate the assembly. An optical phase reference is exchanged between the moving optical benches with a single mode optical fiber (“backlink” fiber). An alternative solution, referred to as in-field pointing, embeds a steering mirror into the optical design, fixing the optical benches and eliminating the backlink fiber, but requiring the additional complication of a two-stage optical design for the telescope. We examine the impact of an in-field pointing design on the scattered light performance.

  13. Improvement of Lighting Uniformity and Phosphor Life in Field Emission Lamps Using Carbon Nanocoils

    Directory of Open Access Journals (Sweden)

    Kun-Ju Chung

    2015-01-01

    Full Text Available The lighting performances and phosphor degradation in field emission lamps (FELs with two different kinds of cathode materials—multiwalled carbon nanotubes (MWCNTs and carbon nanocoils (CNCs—were compared. The MWCNTs and CNCs were selectively synthesized on 304 stainless steel wire substrates dip-coated with nanosized Pd catalysts by controlling the growth temperature in thermal chemical vapor deposition, and the film uniformity can be optimized by adjusting the growth time. FELs were successfully fabricated by assembling these cathode filaments with a glass bulb-type anode. The FEL with the CNC cathode showed much higher lighting uniformity and light-spot density and a lower current at the same voltage than that with the MWCNT cathode filament, and its best luminous efficiency was as high as 75 lm/W at 8 kV. We also found that, for P22, the phosphor degradation can be effectively suppressed by replacing MWCNTs with CNCs in the cathode, due to the much larger total bright spot area and hence much lower current density loading on the anode.

  14. The Φ4-field theory with O(N) symmetry quantified on the light cone

    International Nuclear Information System (INIS)

    Lacroix-Borderies, A.

    1994-09-01

    Quantization on the light cone proceeds through quantization of constraints Hamiltonian systems. A theory on the light cone is characterized by a trivial vacuum. Hence conventional non perturbative vacuum effects are transferred from the ground state to the filed operators which acquires a specific component, the zero mode. The 1/N expansion is applied to the scalar field theory with O(N) symmetry in the framework of light cone quantization. In the symmetric phase a genuine systematic method is established to build up zero mode operators, order by order in 1/√N. This method was not feasible in the conventional approach beyond the 1/N correction. Order by order in 1/√N-1, the method is extended to the broken symmetric phase. First, the equation of motion and constraints have been renormalized to the second order in the expansion in 1/N - 1. The renormalization of diverging contributions to 2- and 4- points functions is treated in a covariant way. The presence of zero modes lead to a non-perturbative renormalization. (authors). 62 refs

  15. Magnetic Modes in Rare Earth Perovskites: A Magnetic-Field-Dependent Inelastic Light Scattering study.

    Science.gov (United States)

    Saha, Surajit; Cao, Bing-Chen; Motapothula, M; Cong, Chun-Xiao; Sarkar, Tarapada; Srivastava, Amar; Sarkar, Soumya; Patra, Abhijeet; Ghosh, Siddhartha; Ariando; Coey, J M D; Yu, Ting; Venkatesan, T

    2016-11-15

    Here, we report the presence of defect-related states with magnetic degrees of freedom in crystals of LaAlO 3 and several other rare-earth based perovskite oxides using inelastic light scattering (Raman spectroscopy) at low temperatures in applied magnetic fields of up to 9 T. Some of these states are at about 140 meV above the valence band maximum while others are mid-gap states at about 2.3 eV. No magnetic impurity could be detected in LaAlO 3 by Proton-Induced X-ray Emission Spectroscopy. We, therefore, attribute the angular momentum-like states in LaAlO 3 to cationic/anionic vacancies or anti-site defects. Comparison with the other rare earth perovskites leads to the empirical rule that the magnetic-field-sensitive transitions require planes of heavy elements (e.g. lanthanum) and oxygen without any other light cations in the same plane. These magnetic degrees of freedom in rare earth perovskites with useful dielectric properties may be tunable by appropriate defect engineering for magneto-optic applications.

  16. Analysis of optically variable devices using a photometric light-field approach

    Science.gov (United States)

    Soukup, Daniel; Å tolc, Svorad; Huber-Mörk, Reinhold

    2015-03-01

    Diffractive Optically Variable Image Devices (DOVIDs), sometimes loosely referred to as holograms, are popular security features for protecting banknotes, ID cards, or other security documents. Inspection, authentication, as well as forensic analysis of these security features are still demanding tasks requiring special hardware tools and expert knowledge. Existing equipment for such analyses is based either on a microscopic analysis of the grating structure or a point-wise projection and recording of the diffraction patterns. We investigated approaches for an examination of DOVID security features based on sampling the Bidirectional Reflectance Distribution Function (BRDF) of DOVIDs using photometric stereo- and light-field-based methods. Our approach is demonstrated on the practical task of automated discrimination between genuine and counterfeited DOVIDs on banknotes. For this purpose, we propose a tailored feature descriptor which is robust against several expected sources of inaccuracy but still specific enough for the given task. The suggested approach is analyzed from both theoretical as well as practical viewpoints and w.r.t. analysis based on photometric stereo and light fields. We show that especially the photometric method provides a reliable and robust tool for revealing DOVID behavior and authenticity.

  17. Integration of real-time 3D capture, reconstruction, and light-field display

    Science.gov (United States)

    Zhang, Zhaoxing; Geng, Zheng; Li, Tuotuo; Pei, Renjing; Liu, Yongchun; Zhang, Xiao

    2015-03-01

    Effective integration of 3D acquisition, reconstruction (modeling) and display technologies into a seamless systems provides augmented experience of visualizing and analyzing real objects and scenes with realistic 3D sensation. Applications can be found in medical imaging, gaming, virtual or augmented reality and hybrid simulations. Although 3D acquisition, reconstruction, and display technologies have gained significant momentum in recent years, there seems a lack of attention on synergistically combining these components into a "end-to-end" 3D visualization system. We designed, built and tested an integrated 3D visualization system that is able to capture in real-time 3D light-field images, perform 3D reconstruction to build 3D model of the objects, and display the 3D model on a large autostereoscopic screen. In this article, we will present our system architecture and component designs, hardware/software implementations, and experimental results. We will elaborate on our recent progress on sparse camera array light-field 3D acquisition, real-time dense 3D reconstruction, and autostereoscopic multi-view 3D display. A prototype is finally presented with test results to illustrate the effectiveness of our proposed integrated 3D visualization system.

  18. Rate Constants of PSII Photoinhibition and its Repair, and PSII Fluorescence Parameters in Field Plants in Relation to their Growth Light Environments.

    Science.gov (United States)

    Miyata, Kazunori; Ikeda, Hiroshi; Nakaji, Masayoshi; Kanel, Dhana Raj; Terashima, Ichiro

    2015-09-01

    The extent of photoinhibition of PSII is determined by a balance between the rate of photodamage to PSII and that of repair of the damaged PSII. It has already been indicated that the rate constants of photodamage (kpi) and repair (krec) of the leaves differ depending on their growth light environment. However, there are no studies using plants in the field. We examined these rate constants and fluorescence parameters of several field-grown plants to determine inter-relationships between these values and the growth environment. The kpi values were strongly related to the excess energy, EY, of the puddle model and non-regulated energy dissipation, Y(NO), of the lake model, both multiplied by the photosynthetically active photon flux density (PPFD) level during the photoinhibitory treatment. In contrast, the krec values corrected against in situ air temperature were very strongly related to the daily PPFD level. The plants from the fields showed higher NPQ than the chamber-grown plants, probably because these field plants acclimated to stronger lightflecks than the averaged growth PPFD. Comparing chamber-grown plants and the field plants, we showed that kpi is determined by the incident light level and the photosynthetic capacities such as in situ rate of PSII electron transport and non-photochemical quenching (NPQ) [e.g. Y(NO)×PPFD] and that krec is mostly determined by the growth light and temperature levels. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Magnetic field generation by circularly polarized laser light and inertial plasma confinement in a miniature 'Magnetic Bottle' induced by circularly polarized laser light

    International Nuclear Information System (INIS)

    Kolka, E.

    1993-07-01

    A new concept of hot plasma confinement in a miniature magnetic bottle induced by circularly polarized laser light is suggested in this work. Magnetic fields generated by circularly polarized laser light may be of the order of megagauss. In this configuration the circularly polarized laser light is used to get confinement of a plasma contained in a good conductor vessel. The poloidal magnetic field induced by the circularly polarized laser and the efficiency of laser absorption by the plasma are calculated in this work. The confinement in this scheme is supported by the magnetic forces and the Lawson criterion for a DT plasma might be achieved for number density n=5*10 21 cm -3 and confinement time τ= 20 nsec. The laser and the plasma parameters required to get an energetic gain are calculated. (authors)

  20. How diffusivity, thermocline and incident light intensity modulate the dynamics of deep chlorophyll maximum in Tyrrhenian Sea.

    Directory of Open Access Journals (Sweden)

    Davide Valenti

    Full Text Available During the last few years theoretical works have shed new light and proposed new hypotheses on the mechanisms which regulate the spatio-temporal behaviour of phytoplankton communities in marine pelagic ecosystems. Despite this, relevant physical and biological issues, such as effects of the time-dependent mixing in the upper layer, competition between groups, and dynamics of non-stationary deep chlorophyll maxima, are still open questions. In this work, we analyze the spatio-temporal behaviour of five phytoplankton populations in a real marine ecosystem by using a one-dimensional reaction-diffusion-taxis model. The study is performed, taking into account the seasonal variations of environmental variables, such as light intensity, thickness of upper mixed layer and profiles of vertical turbulent diffusivity, obtained starting from experimental findings. Theoretical distributions of phytoplankton cell concentration was converted in chlorophyll concentration, and compared with the experimental profiles measured in a site of the Tyrrhenian Sea at four different times (seasons of the year, during four different oceanographic cruises. As a result we find a good agreement between theoretical and experimental distributions of chlorophyll concentration. In particular, theoretical results reveal that the seasonal changes of environmental variables play a key role in the phytoplankton distribution and determine the properties of the deep chlorophyll maximum. This study could be extended to other marine ecosystems to predict future changes in the phytoplankton biomass due to global warming, in view of devising strategies to prevent the decline of the primary production and the consequent decrease of fish species.

  1. WOW: light print, light propel, light point

    Science.gov (United States)

    Glückstad, Jesper; Bañas, Andrew; Aabo, Thomas; Palima, Darwin

    2012-10-01

    We are presenting so-called Wave-guided Optical Waveguides (WOWs) fabricated by two-photon polymerization and capable of being optically manipulated into any arbitrary orientation. By integrating optical waveguides into the structures we have created freestanding waveguides which can be positioned anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation. In a broader context, this research shows that optically trapped micro-fabricated structures can potentially help bridge the diffraction barrier. This structure-mediated paradigm may be carried forward to open new possibilities for exploiting beams from far-field optics down to the sub-wavelength domain.

  2. Quantum field kinetics of QCD quark-gluon transport theory for light-cone dominated processes

    CERN Document Server

    Kinder-Geiger, Klaus

    1996-01-01

    A quantum kinetic formalism is developed to study the dynamical interplay of quantum and statistical-kinetic properties of non-equilibrium multi-parton systems produced in high-energy QCD processes. The approach provides the means to follow the quantum dynamics in both space-time and energy-momentum, starting from an arbitrary initial configuration of high-momentum quarks and gluons. Using a generalized functional integral representation and adopting the `closed-time-path' Green function techniques, a self-consistent set of equations of motions is obtained: a Ginzburg-Landau equation for a possible color background field, and Dyson-Schwinger equations for the 2-point functions of the gluon and quark fields. By exploiting the `two-scale nature' of light-cone dominated QCD processes, i.e. the separation between the quantum scale that specifies the range of short-distance quantum fluctuations, and the kinetic scale that characterizes the range of statistical binary inter- actions, the quantum-field equations of ...

  3. Direct imaging of phase objects enables conventional deconvolution in bright field light microscopy.

    Directory of Open Access Journals (Sweden)

    Carmen Noemí Hernández Candia

    Full Text Available In transmitted optical microscopy, absorption structure and phase structure of the specimen determine the three-dimensional intensity distribution of the image. The elementary impulse responses of the bright field microscope therefore consist of separate absorptive and phase components, precluding general application of linear, conventional deconvolution processing methods to improve image contrast and resolution. However, conventional deconvolution can be applied in the case of pure phase (or pure absorptive objects if the corresponding phase (or absorptive impulse responses of the microscope are known. In this work, we present direct measurements of the phase point- and line-spread functions of a high-aperture microscope operating in transmitted bright field. Polystyrene nanoparticles and microtubules (biological polymer filaments serve as the pure phase point and line objects, respectively, that are imaged with high contrast and low noise using standard microscopy plus digital image processing. Our experimental results agree with a proposed model for the response functions, and confirm previous theoretical predictions. Finally, we use the measured phase point-spread function to apply conventional deconvolution on the bright field images of living, unstained bacteria, resulting in improved definition of cell boundaries and sub-cellular features. These developments demonstrate practical application of standard restoration methods to improve imaging of phase objects such as cells in transmitted light microscopy.

  4. Field-programmable gate array based controller for multi spot light-addressable potentiometric sensors with integrated signal correction mode

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Carl Frederik; Schusser, Sebastian; Spelthahn, Heiko [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Heinrich-Mussmann-Strasse 1, 52428 Juelich (Germany); Institute of Bio- and Nanosystems (IBN-2), Research Centre Juelich GmbH, 52425 Juelich (Germany); Wagner, Torsten; Yoshinobu, Tatsuo [Tohoku University, Department of Electronic Engineering, 6-6-05 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Schoening, Michael J., E-mail: schoening@fh-aachen.de [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Heinrich-Mussmann-Strasse 1, 52428 Juelich (Germany); Institute of Bio- and Nanosystems (IBN-2), Research Centre Juelich GmbH, 52425 Juelich (Germany)

    2011-11-01

    Highlights: > Flexible up-scalable design of a light-addressable potentiometric sensor set-up. > Utilisation of a field-programmable gate array to address LAPS measurement spots. > Measurements in amplitude-mode and phase-mode for different pH solutions. > Amplitude, phase and frequency behaviour of LAPS for single and multiple light stimulus. > Signal calibration method by brightness control to compensated systematic errors. - Abstract: A light-addressable potentiometric sensor (LAPS) can measure the concentration of one or several analytes at the sensor surface simultaneously in a spatially resolved manner. A modulated light pointer stimulates the semiconductor structure at the area of interest and a responding photocurrent can be read out. By simultaneous stimulation of several areas with light pointers of different modulation frequencies, the read out can be performed at the same time. With the new proposed controller electronic based on a field-programmable gate array (FPGA), it is possible to control the modulation frequencies, phase shifts, and light brightness of multiple light pointers independently and simultaneously. Thus, it is possible to investigate the frequency response of the sensor, and to examine the analyte concentration by the determination of the surface potential with the help of current/voltage curves and phase/voltage curves. Additionally, the ability to individually change the light intensities of each light pointer is used to perform signal correction.

  5. Break up of light ions in the nuclear and Coulomb field of nuclei

    International Nuclear Information System (INIS)

    Srivastava, D.K.

    1985-12-01

    The break up of light ion projectiles in the nuclear and Coulomb field of nuclei is considered. Current theoretical concepts for describing break up processes and their theoretical features are discussed. An alternative method, based on a prior-interaction DWBA, is introduced for the calculation of the direct elastic break up cross sections. This method reveals the role of the internal momentum distribution of the break up fragments and includes corresponding 'finite range' effects. The Coulomb break up of 6 Li is studied on the basis of a quasi-sequential break up approach (following Rybicki and Austern) and results are obtained for very low relative energies of the emerging α-particles and deuteron fragments. The astrophysical interest in these cross sections is noted. A view on further extensions of the break up theory is given. (orig.) [de

  6. Fractional-topological-charge-induced vortex birth and splitting of light fields on the submicron scale

    Science.gov (United States)

    Fang, Yiqi; Lu, Qinghong; Wang, Xiaolei; Zhang, Wuhong; Chen, Lixiang

    2017-02-01

    The study of vortex dynamics is of fundamental importance in understanding the structured light's propagation behavior in the realm of singular optics. Here, combining with the large-angle holographic lithography in photoresist, a simple experiment to trace and visualize the vortex birth and splitting of light fields induced by various fractional topological charges is reported. For a topological charge M =1.76 , the recorded microstructures reveal that although it finally leads to the formation of a pair of fork gratings, these two vortices evolve asynchronously. More interestingly, it is observed on the submicron scale that high-order topological charges M =3.48 and 3.52, respectively, give rise to three and four characteristic forks embedded in the samples with one-wavelength resolution of about 450 nm. Numerical simulations based on orbital angular momentum eigenmode decomposition support well the experimental observations. Our method could be applied effectively to study other structured matter waves, such as the electron and neutron beams.

  7. NICOLAU: compact unit for photometric characterization of automotive lighting from near-field measurements

    Science.gov (United States)

    Royo, Santiago; Arranz, Maria J.; Arasa, Josep; Cattoen, Michel; Bosch, Thierry

    2005-02-01

    The present works depicts a measurement technique intended to enhance the characterization procedures of the photometric emissions of automotive headlamps, with potential applications to any light source emission, either automotive or non-automotive. A CCD array with a precisely characterized optical system is used for sampling the luminance field of the headlamp just a few centimetres in front of it, by combining deflectometric techniques (yielding the direction of the light beams) and photometric techniques (yielding the energy travelling in each direction). The CCD array scans the measurement plane using a self-developed mechanical unit and electronics, and then image-processing techniques are used for obtaining the photometric behaviour of the headlamp in any given plane, in particular in the plane and positions required by current normative, but also on the road, on traffic signs, etc. An overview of the construction of the system, of the considered principle of measurement, and of the main calibrations performed on the unit is presented. First results concerning relative measurements are presented compared both to reference data from a photometric tunnel and from a plane placed 5m away from the source. Preliminary results for the absolute photometric calibration of the system are also presented for different illumination beams of different headlamps (driving and passing beam).

  8. SU-F-T-463: Light-Field Based Dynalog Verification

    International Nuclear Information System (INIS)

    Atwal, P; Ramaseshan, R

    2016-01-01

    Purpose: To independently verify leaf positions in so-called dynalog files for a Varian iX linac with a Millennium 120 MLC. This verification provides a measure of confidence that the files can be used directly as part of a more extensive intensity modulated radiation therapy / volumetric modulated arc therapy QA program. Methods: Initial testing used white paper placed at the collimator plane and a standard hand-held digital camera to image the light and shadow of a static MLC field through the paper. Known markings on the paper allow for image calibration. Noise reduction was attempted with removal of ‘inherent noise’ from an open-field light image through the paper, but the method was found to be inconsequential. This is likely because the environment could not be controlled to the precision required for the sort of reproducible characterization of the quantum noise needed in order to meaningfully characterize and account for it. A multi-scale iterative edge detection algorithm was used for localizing the leaf ends. These were compared with the planned locations from the treatment console. Results: With a very basic setup, the image of the central bank A leaves 15–45, which are arguably the most important for beam modulation, differed from the planned location by [0.38±0.28] mm. Similarly, for bank B leaves 15–45 had a difference of [0.42±0.28] mm Conclusion: It should be possible to determine leaf position accurately with not much more than a modern hand-held camera and some software. This means we can have a periodic and independent verification of the dynalog file information. This is indicated by the precision already achieved using a basic setup and analysis methodology. Currently, work is being done to reduce imaging and setup errors, which will bring the leaf position error down further, and allow meaningful analysis over the full range of leaves.

  9. SU-F-T-463: Light-Field Based Dynalog Verification

    Energy Technology Data Exchange (ETDEWEB)

    Atwal, P; Ramaseshan, R [BC Cancer Agency, Abbotsford, BC (Canada)

    2016-06-15

    Purpose: To independently verify leaf positions in so-called dynalog files for a Varian iX linac with a Millennium 120 MLC. This verification provides a measure of confidence that the files can be used directly as part of a more extensive intensity modulated radiation therapy / volumetric modulated arc therapy QA program. Methods: Initial testing used white paper placed at the collimator plane and a standard hand-held digital camera to image the light and shadow of a static MLC field through the paper. Known markings on the paper allow for image calibration. Noise reduction was attempted with removal of ‘inherent noise’ from an open-field light image through the paper, but the method was found to be inconsequential. This is likely because the environment could not be controlled to the precision required for the sort of reproducible characterization of the quantum noise needed in order to meaningfully characterize and account for it. A multi-scale iterative edge detection algorithm was used for localizing the leaf ends. These were compared with the planned locations from the treatment console. Results: With a very basic setup, the image of the central bank A leaves 15–45, which are arguably the most important for beam modulation, differed from the planned location by [0.38±0.28] mm. Similarly, for bank B leaves 15–45 had a difference of [0.42±0.28] mm Conclusion: It should be possible to determine leaf position accurately with not much more than a modern hand-held camera and some software. This means we can have a periodic and independent verification of the dynalog file information. This is indicated by the precision already achieved using a basic setup and analysis methodology. Currently, work is being done to reduce imaging and setup errors, which will bring the leaf position error down further, and allow meaningful analysis over the full range of leaves.

  10. Circadian rhythms in the incidence of apoptotic cells and number of clonogenic cells in intestinal crypts after radiation using normal and reversed light conditions

    International Nuclear Information System (INIS)

    Ijiri, K.; Potten, C.S.

    1988-01-01

    Variations in the number of radiation-induced morphologically dead or dying cells (apoptotic cells) in the crypts in the small intestine of the mouse have been studied throughout a 24-h period under a normal light regimen. A clear circadian rhythm was displayed in the apoptotic incidence 3 or 6 h after irradiation for each gamma-ray dose studied (range 0.14-9.0 Gy). The most prominent circadian rhythm was obtained after 0.5 Gy. Peak time of day for inducing apoptosis was 06.00-09.00 h, and the trough occurred at 18.00-21.00 h. Some mice were also transferred to a reversed light cycle, and irradiated on different days after transfer. Apoptosis induced by 0.5 Gy or 9.0 Gy, or number of surviving crypts (microcolonies) after 11.0 Gy or 13.0 Gy was examined. The transition point for reversal of circadian rhythm in apoptosis (after 0.5 Gy) occurred 7 days after transfer and the rhythm was reversed by 14 days. The rhythm for crypt survival (i.e. for clonogenic cell radiosensitivity) was disturbed on 1 day and transition point for reversal occurred 3 days after transfer. The rhythm became reversed by 7 days. (author)

  11. Hamiltonian Light-Front Field Theory: Recent Progress and Tantalizing Prospects

    International Nuclear Information System (INIS)

    Vary, J. P.

    2012-01-01

    Fundamental theories, such as quantum electrodynamics and quantum chromodynamics promise great predictive power addressing phenomena over vast scales from the microscopic to cosmic scales. However, new non-perturbative tools are required for physics to span from one scale to the next. I outline recent theoretical and computational progress to build these bridges and provide illustrative results for Hamiltonian Light Front Field Theory. One key area is our development of basis function approaches that cast the theory as a Hamiltonian matrix problem while preserving a maximal set of symmetries. Regulating the theory with an external field that can be removed to obtain the continuum limit offers additional possibilities as seen in an application to the anomalous magnetic moment of the electron. Recent progress capitalizes on algorithm and computer developments for setting up and solving very large sparse matrix eigenvalue problems. Matrices with dimensions of 20 billion basis states are now solved on leadership-class computers for their low-lying eigenstates and eigenfunctions. (author)

  12. Experimental constraints on light scalar field models in cosmology and particle physics (SNLS and CMS experiments)

    International Nuclear Information System (INIS)

    Neveu, Jeremy

    2014-01-01

    The nature of dark energy and dark matter is still unknown today. Light scalar field models have been proposed to explain the late-time accelerated expansion of the Universe and the apparent abundance of non-baryonic matter. In the first part of this thesis, the Galileon theory, a well-posed modified gravity theory preserving the local gravitation thanks to the Vainshtein screening effect, is accurately tested against recent cosmological data. Observational constraints are derived on the model parameters using cosmological distance and growth rate of structure measurements. A good agreement is observed between data and theory predictions. The Galileon theory appears therefore as a promising alternative to the cosmological constant scenario. In the second part, the dark matter question is explored through an extra-dimension theory containing massive and stable scalar fields called Branons. Branon production is searched for in the proton-proton collisions that were collected by the Compact Muon Solenoid experiment in 2012 at the Large Hadron Collider. Events with a single photon and transverse missing energy are selected in this data set and compared to the Standard Model and instrumental background estimates. No signature of new physics is observed, so experimental limits on the Branon model parameters are derived. This thesis concludes with some ideas to reach an unified description of both models in the frame of extra-dimension theories. (author) [fr

  13. Selected Topics in Light Front Field Theory and Applications to the High Energy Phenomena

    Science.gov (United States)

    Kundu, Rajen

    1999-10-01

    In this thesis, we have presented some of the aspects of light-front (LF) field theory through their successful application in the Deep Inelastic Scattering (DIS). We have developed a LFQCD Hamiltonian description of the DIS structure functions starting from Bjorken-Johnson-Low limit of virtual forward Compton scattering amplitude and using LF current commutators. We worked in the LF gauge A^+=0 and used the old-fashioned LFQCD perturbation theory in our calculations. The importance of our work are summarized below. Our approach shares the intution of parton model and addresses directly the structure functions, which are experimental objects, instead of its moments as in OPE method. Moreover, it can potentially incorporate the non-perturbative contents of the structure functions as we have demonstrated by introducing a new factorization scheme. In the context of nucleonic helicity structure, the well known gauge fixed LF helicity operator is shown to provide consistent physical information and helps us defining new relevant structure functions. The anomalous dimensions relevant for the Q^2-evolution of such structure functions are calculated. Our study is important in establishing the equivalance of LF field theory and the usual equal-time one through perturbative calculations of the dressed parton structure functions reproducing the well known results. Also the importance of Gallilean boost symmetry in understanding the correctness of any higher order calculation using (x^+)-ordered LFQCD perturbation theory are emphasized.

  14. Automated x-ray/light field congruence using the LINAC EPID panel

    Energy Technology Data Exchange (ETDEWEB)

    Polak, Wojciech [Department of Medical Physics, Royal Surrey County Hospital, Guildford GU2 7XX (United Kingdom); Department of Medical Physics, Radiotherapy Section, Queen Alexandra Hospital NHS Trust, Portsmouth PO6 3LY (United Kingdom); O' Doherty, Jim [Division of Imaging Sciences and Biomedical Engineering, King' s College London, London SE1 7EH, United Kingdom and Department of Medical Physics, Royal Surrey County Hospital, Guildford GU2 7XX (United Kingdom); Jones, Matt [Department of Medical Physics, Royal Surrey County Hospital, Guildford GU2 7XX (United Kingdom)

    2013-03-15

    Purpose: X-ray/light field alignment is a test described in many guidelines for the routine quality control of clinical linear accelerators (LINAC). Currently, the gold standard method for measuring alignment is through utilization of radiographic film. However, many modern LINACs are equipped with an electronic portal imaging device (EPID) that may be used to perform this test and thus subsequently reducing overall cost, processing, and analysis time, removing operator dependency and the requirement to sustain the departmental film processor. Methods: This work describes a novel method of utilizing the EPID together with a custom inhouse designed jig and automatic image processing software allowing measurement of the light field size, x-ray field size, and congruence between them. The authors present results of testing the method for aS1000 and aS500 Varian EPID detectors for six LINACs at a range of energies (6, 10, and 15 MV) in comparison with the results obtained from the use of radiographic film. Results: Reproducibility of the software in fully automatic operation under a range of operating conditions for a single image showed a congruence of 0.01 cm with a coefficient of variation of 0. Slight variation in congruence repeatability was noted through semiautomatic processing by four independent operators due to manual marking of positions on the jig. Testing of the methodology using the automatic method shows a high precision of 0.02 mm compared to a maximum of 0.06 mm determined by film processing. Intraindividual examination of operator measurements of congruence was shown to vary as much as 0.75 mm. Similar congruence measurements of 0.02 mm were also determined for a lower resolution EPID (aS500 model), after rescaling of the image to the aS1000 image size. Conclusions: The designed methodology was proven to be time efficient, cost effective, and at least as accurate as using the gold standard radiographic film. Additionally, congruence testing can be

  15. Automated x-ray/light field congruence using the LINAC EPID panel

    International Nuclear Information System (INIS)

    Polak, Wojciech; O’Doherty, Jim; Jones, Matt

    2013-01-01

    Purpose: X-ray/light field alignment is a test described in many guidelines for the routine quality control of clinical linear accelerators (LINAC). Currently, the gold standard method for measuring alignment is through utilization of radiographic film. However, many modern LINACs are equipped with an electronic portal imaging device (EPID) that may be used to perform this test and thus subsequently reducing overall cost, processing, and analysis time, removing operator dependency and the requirement to sustain the departmental film processor. Methods: This work describes a novel method of utilizing the EPID together with a custom inhouse designed jig and automatic image processing software allowing measurement of the light field size, x-ray field size, and congruence between them. The authors present results of testing the method for aS1000 and aS500 Varian EPID detectors for six LINACs at a range of energies (6, 10, and 15 MV) in comparison with the results obtained from the use of radiographic film. Results: Reproducibility of the software in fully automatic operation under a range of operating conditions for a single image showed a congruence of 0.01 cm with a coefficient of variation of 0. Slight variation in congruence repeatability was noted through semiautomatic processing by four independent operators due to manual marking of positions on the jig. Testing of the methodology using the automatic method shows a high precision of 0.02 mm compared to a maximum of 0.06 mm determined by film processing. Intraindividual examination of operator measurements of congruence was shown to vary as much as 0.75 mm. Similar congruence measurements of 0.02 mm were also determined for a lower resolution EPID (aS500 model), after rescaling of the image to the aS1000 image size. Conclusions: The designed methodology was proven to be time efficient, cost effective, and at least as accurate as using the gold standard radiographic film. Additionally, congruence testing can be

  16. Automated x-ray/light field congruence using the LINAC EPID panel.

    Science.gov (United States)

    Polak, Wojciech; O'Doherty, Jim; Jones, Matt

    2013-03-01

    X-ray/light field alignment is a test described in many guidelines for the routine quality control of clinical linear accelerators (LINAC). Currently, the gold standard method for measuring alignment is through utilization of radiographic film. However, many modern LINACs are equipped with an electronic portal imaging device (EPID) that may be used to perform this test and thus subsequently reducing overall cost, processing, and analysis time, removing operator dependency and the requirement to sustain the departmental film processor. This work describes a novel method of utilizing the EPID together with a custom inhouse designed jig and automatic image processing software allowing measurement of the light field size, x-ray field size, and congruence between them. The authors present results of testing the method for aS1000 and aS500 Varian EPID detectors for six LINACs at a range of energies (6, 10, and 15 MV) in comparison with the results obtained from the use of radiographic film. Reproducibility of the software in fully automatic operation under a range of operating conditions for a single image showed a congruence of 0.01 cm with a coefficient of variation of 0. Slight variation in congruence repeatability was noted through semiautomatic processing by four independent operators due to manual marking of positions on the jig. Testing of the methodology using the automatic method shows a high precision of 0.02 mm compared to a maximum of 0.06 mm determined by film processing. Intraindividual examination of operator measurements of congruence was shown to vary as much as 0.75 mm. Similar congruence measurements of 0.02 mm were also determined for a lower resolution EPID (aS500 model), after rescaling of the image to the aS1000 image size. The designed methodology was proven to be time efficient, cost effective, and at least as accurate as using the gold standard radiographic film. Additionally, congruence testing can be easily performed for all four cardinal

  17. Nanomagnetic behavior of fullerene thin films in Earth magnetic field in dark and under polarization light influences.

    Science.gov (United States)

    Koruga, Djuro; Nikolić, Aleksandra; Mihajlović, Spomenko; Matija, Lidija

    2005-10-01

    In this paper magnetic fields intensity of C60 thin films of 60 nm and 100 nm thickness under the influence of polarization lights are presented. Two proton magnetometers were used for measurements. Significant change of magnetic field intensity in range from 2.5 nT to 12.3 nT is identified as a difference of dark and polarization lights of 60 nm and 100 nm thin films thickness, respectively. Specific power density of polarization light was 40 mW/cm2. Based on 200 measurement data average value of difference between magnetic intensity of C60 thin films, with 60 nm and 100 nm thickness, after influence of polarization light, were 3.9 nT and 9.9 nT respectively.

  18. Quantum field kinetics of QCD: Quark-gluon transport theory for light-cone-dominated processes

    International Nuclear Information System (INIS)

    Geiger, K.

    1996-01-01

    A quantum-kinetic formalism is developed to study the dynamical interplay of quantum and statistical-kinetic properties of nonequilibrium multiparton systems produced in high-energy QCD processes. The approach provides the means to follow the quantum dynamics in both space-time and energy-momentum, starting from an arbitrary initial configuration of high-momentum quarks and gluons. Using a generalized functional integral representation and adopting the open-quote open-quote closed-time-path close-quote close-quote Green function techniques, a self-consistent set of equations of motions is obtained: a Ginzburg-Landau equation for a possible color background field, and Dyson-Schwinger equations for the two-point functions of the gluon and quark fields. By exploiting the open-quote open-quote two-scale nature close-quote close-quote of light-cone-dominated QCD processes, i.e., the separation between the quantum scale that specifies the range of short-distance quantum fluctuations, and the kinetic scale that characterizes the range of statistical binary interactions, the quantum field equations of motion are converted into a corresponding set of open-quote open-quote renormalization equations close-quote close-quote and open-quote open-quote transport equations.close-quote close-quote The former describe renormalization and dissipation effects through the evolution of the spectral density of individual, dressed partons, whereas the latter determine the statistical occurrence of scattering processes among these dressed partons. The renormalization equations and the transport equations are coupled, and, hence, must be solved self-consistently. This amounts to evolving the multiparton system, from a specified initial configuration, in time and full seven-dimensional phase space, constrained by the Heisenberg uncertainty principle. (Abstract Truncated)

  19. Highly polarized light from stable ordered magnetic fields in GRB 120308A.

    Science.gov (United States)

    Mundell, C G; Kopač, D; Arnold, D M; Steele, I A; Gomboc, A; Kobayashi, S; Harrison, R M; Smith, R J; Guidorzi, C; Virgili, F J; Melandri, A; Japelj, J

    2013-12-05

    After the initial burst of γ-rays that defines a γ-ray burst (GRB), expanding ejecta collide with the circumburst medium and begin to decelerate at the onset of the afterglow, during which a forward shock travels outwards and a reverse shock propagates backwards into the oncoming collimated flow, or 'jet'. Light from the reverse shock should be highly polarized if the jet's magnetic field is globally ordered and advected from the central engine, with a position angle that is predicted to remain stable in magnetized baryonic jet models or vary randomly with time if the field is produced locally by plasma or magnetohydrodynamic instabilities. Degrees of linear polarization of P ≈ 10 per cent in the optical band have previously been detected in the early afterglow, but the lack of temporal measurements prevented definitive tests of competing jet models. Hours to days after the γ-ray burst, polarization levels are low (P < 4 per cent), when emission from the shocked ambient medium dominates. Here we report the detection of P =28(+4)(-4) per cent in the immediate afterglow of Swift γ-ray burst GRB 120308A, four minutes after its discovery in the γ-ray band, decreasing to P = 16(+5)(-4) per cent over the subsequent ten minutes. The polarization position angle remains stable, changing by no more than 15 degrees over this time, with a possible trend suggesting gradual rotation and ruling out plasma or magnetohydrodynamic instabilities. Instead, the polarization properties show that GRBs contain magnetized baryonic jets with large-scale uniform fields that can survive long after the initial explosion.

  20. Effect of light on N2 fixation and net nitrogen release of Trichodesmium in a field study

    Science.gov (United States)

    Lu, Yangyang; Wen, Zuozhu; Shi, Dalin; Chen, Mingming; Zhang, Yao; Bonnet, Sophie; Li, Yuhang; Tian, Jiwei; Kao, Shuh-Ji

    2018-01-01

    Dinitrogen fixation (NF) by marine cyanobacteria is an important pathway to replenish the oceanic bioavailable nitrogen inventory. Light is the key to modulating NF; however, field studies investigating the light response curve (NF-I curve) of NF rate and the effect of light on diazotroph-derived nitrogen (DDN) net release are relatively sparse in the literature, hampering prediction using models. A dissolution method was applied using uncontaminated 15N2 gas to examine how the light changes may influence the NF intensity and DDN net release in the oligotrophic ocean. Experiments were conducted at stations with diazotrophs dominated by filamentous cyanobacterium Trichodesmium spp. in the western Pacific and the South China Sea. The effect of light on carbon fixation (CF) was measured in parallel using the 13C tracer method specifically for a station characterized by Trichodesmium bloom. Both NF-I and CF-I curves showed a Ik (light saturation coefficient) range of 193 to 315 µE m-2 s-1, with light saturation at around 400 µE m-2 s-1. The proportion of DDN net release ranged from ˜ 6 to ˜ 50 %, suggesting an increasing trend as the light intensity decreased. At the Trichodesmium bloom station, we found that the CF / NF ratio was light-dependent and the ratio started to increase as light was lower than the carbon compensation point of 200 µE m-2 s-1. Under low-light stress, Trichodesmium physiologically preferred to allocate more energy for CF to alleviate the intensive carbon consumption by respiration; thus, there is a metabolism tradeoff between CF and NF pathways. Results showed that short-term ( energy associated with the variation in light intensity would be helpful for prediction of the global biogeochemical cycle of N by models involving Trichodesmium blooms.

  1. A cross-platform solution for light field based 3D telemedicine.

    Science.gov (United States)

    Wang, Gengkun; Xiang, Wei; Pickering, Mark

    2016-03-01

    Current telehealth services are dominated by conventional 2D video conferencing systems, which are limited in their capabilities in providing a satisfactory communication experience due to the lack of realism. The "immersiveness" provided by 3D technologies has the potential to promote telehealth services to a wider range of applications. However, conventional stereoscopic 3D technologies are deficient in many aspects, including low resolution and the requirement for complicated multi-camera setup and calibration, and special glasses. The advent of light field (LF) photography enables us to record light rays in a single shot and provide glasses-free 3D display with continuous motion parallax in a wide viewing zone, which is ideally suited for 3D telehealth applications. As far as our literature review suggests, there have been no reports of 3D telemedicine systems using LF technology. In this paper, we propose a cross-platform solution for a LF-based 3D telemedicine system. Firstly, a novel system architecture based on LF technology is established, which is able to capture the LF of a patient, and provide an immersive 3D display at the doctor site. For 3D modeling, we further propose an algorithm which is able to convert the captured LF to a 3D model with a high level of detail. For the software implementation on different platforms (i.e., desktop, web-based and mobile phone platforms), a cross-platform solution is proposed. Demo applications have been developed for 2D/3D video conferencing, 3D model display and edit, blood pressure and heart rate monitoring, and patient data viewing functions. The demo software can be extended to multi-discipline telehealth applications, such as tele-dentistry, tele-wound and tele-psychiatry. The proposed 3D telemedicine solution has the potential to revolutionize next-generation telemedicine technologies by providing a high quality immersive tele-consultation experience. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Light propagation in 2PN approximation in the field of one moving monopole I. Initial value problem

    Science.gov (United States)

    Zschocke, Sven

    2018-03-01

    In this investigation the light propagation in the gravitational field of one arbitrarily moving body with monopole structure is considered in the second post-Newtonian approximation. It is found that the light trajectory depends on the acceleration of the body. Some of these acceleration terms are important in order to get well-defined logarithmic functions with dimensionless arguments, while all the other acceleration terms are negligible on the pico-second level of accuracy in time-delay measurements. The expressions of the observables total light deflection and time delay are determined.

  3. Optical trapping of cold neutral atoms using a two-color evanescent light field around a carbon nanotube

    International Nuclear Information System (INIS)

    Nga, Do Thi; Viet, Nguyen Ai; Nga, Dao Thi Thuy; Lan, Nguyen Thi Phuong

    2014-01-01

    We suggest a new schema of trapping cold atoms using a two-color evanescent light field around a carbon nanotube. The two light fields circularly polarized sending through a carbon nanotube generates an evanescent wave around this nanotube. By evanescent effect, the wave decays away from the nanotube producing a set of trapping minima of the total potential in the transverse plane as a ring around the nanotube. This schema allows capture of atoms to a cylindrical shell around the nanotube. We consider some possible boundary conditions leading to the non-trivial bound state solution. Our result will be compared to some recent trapping models and our previous trapping models.

  4. Perspectives of Light-Front Quantized Field Theory: Some New Results

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Prem P.

    1999-08-13

    A review of some basic topics in the light-front (LF) quantization of relativistic field theory is made. It is argued that the LF quantization is equally appropriate as the conventional one and that they lead, assuming the microcausality principle, to the same physical content. This is confirmed in the studies on the LF of the spontaneous symmetry breaking (SSB), of the degenerate vacua in Schwinger model (SM) and Chiral SM (CSM), of the chiral boson theory, and of the QCD in covariant gauges among others. The discussion on the LF is more economical and more transparent than that found in the conventional equal-time quantized theory. The removal of the constraints on the LF phase space by following the Dirac method, in fact, results in a substantially reduced number of independent dynamical variables. Consequently, the descriptions of the physical Hilbert space and the vacuum structure, for example, become more tractable. In the context of the Dyson-Wick perturbation theory the relevant propagators in the front form theory are causal. The Wick rotation can then be performed to employ the Euclidean space integrals in momentum space. The lack of manifest covariance becomes tractable, and still more so if we employ, as discussed in the text, the Fourier transform of the fermionic field based on a special construction of the LF spinor. The fact that the hyperplanes x{sup {+-}} = 0 constitute characteristic surfaces of the hyperbolic partial differential equation is found irrelevant in the quantized theory; it seems sufficient to quantize the theory on one of the characteristic hyperplanes.

  5. Photosynthetic accessory pigments: evidence for the influence of phycoerythrin on the submarine light field

    International Nuclear Information System (INIS)

    Hoge, F.E.; Swift, R.N.

    1990-01-01

    Oceanic phytoplankton chlorophyll is known to produce a very significant influence on the optical properties of the ocean. The chlorophyll-driven optical properties are in fact so strong as to allow global satellite mapping of the pigment concentration in the upper ocean using upwelled waterleaving radiances. In this paper, extensive experimental evidence is presented to strongly suggest that upwelled water-leaving spectral radiances (and therefore the submarine light field source) also include physical scattering and absorption effects of photosynthetic accessory pigments such as phycoerythrin. In the water column, the presence of phycoerythrin was measured over wide regions of the ocean using well-established airborne laser-induced spectral fluorescence techniques. Active-passive correlation spectroscopy methods revealed that concurrently measured water-leaving spectral radiances in the ∼ 600 nm spectral region were highly correlated with the laser-induced phycoerythrin pigment fluorescence. The analysis was performed on data sets in which the phycoerythrin and chlorophyll fluorescence were not coherent in order to permit the unambiguous evaluation of results. (author)

  6. Light hydrocarbons as redox and temperature indicators in the geothermal field of El Tatio (northern Chile)

    Energy Technology Data Exchange (ETDEWEB)

    Tassi, F. [University of Florence (Italy). Dept. of Earth Sciences; Martinez, C. [University Catolica del Norte, Antofagasta (Chile). Dept. of Earth Science; Vaselli, O. [University of Florence (Italy). Dept. of Earth Sciences; Institute of Geosciences and Earth Resources, Florence (Italy). National Council of Research; Capaccioni, B. [University of Urbino (Italy). Institute of Volcanology and Geochemistry; Viramonte, J. [National University of Salta (Argentina). Institute GEONORTE and CONICET

    2005-11-15

    El Tatio (northern Chile), one of the largest geothermal fields of South America, is presently undergoing a new program of geothermal exploration, after the failure of the first exploration phase in the early 1970s. The geochemical features of the fluid discharges characterizing this system mainly consist of boiling pools and fumaroles, and represent the result of a complex mixing process involving 3 main components: (i) hydrothermal; (ii) atmospheric; (iii) magmatic. Chemical reactions involving light hydrocarbons equilibrate at higher temperature than those directly measured in the geothermal wells and calculated on the basis of the composition of the inorganic gas species. This suggests that in the deeper parts of the hydrothermal system temperatures higher than 300{sup o}C may be achieved. Such results can have a strong impact for the evaluation of the potential resources of this geothermal system. Moreover, the chemical characteristics of the organic gas fraction allow the assessment of the chemical-physical conditions governing the geochemical processes acting on geothermal fluids at depth. (author)

  7. Influence of heterojunction interface on exciplex emission from organic light-emitting diodes under electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shengyi; Zhang, Xiulong; Lou, Zhidong; Hou, Yanbing [Beijing Jiaotong University, Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing (China)

    2008-03-15

    In this paper, electroluminescence from organic light-emitting diodes based on 2-(4'-biphenyl)-5-(4{sup ''}-tert-butylphenyl)-1,3,4-oxadiazole (PBD) and N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) is reported. Based on the exciplex emission from the TPD/PBD interface under high electric fields, the influence of the TPD/PBD interface on exciplex emission was investigated by increasing the number of TPD/PBD interfaces while keeping both the total thickness of the TPD layer and the PBD layer constant in the multiple quantum-wells (MQW) device ITO/TPD/[PBD/TPD]{sub n}/PBD/Al (n is the well number that was varied from 0 to 3). Our experimental data shows that exciplex emission can be enhanced by suitably increasing the well number of this kind of MQW-like device. (orig.)

  8. Spontaneous symmetry breaking of (1+1)-dimensional φ4 theory in light-front field theory

    International Nuclear Information System (INIS)

    Bender, C.M.; Pinsky, S.; van de Sande, B.

    1993-01-01

    We study spontaneous symmetry breaking in (1+1)-dimensional φ 4 theory using the light-front formulation of field theory. Since the physical vacuum is always the same as the perturbative vacuum in light-front field theory the fields must develop a vacuum expectation value through the zero-mode components of the field. We solve the nonlinear operator equation for the zero mode in the one-mode approximation. We find that spontaneous symmetry breaking occurs at λ critical =4π(3+ √3 )μ 2 , which is consistent with the value λ critical =54.27μ 2 obtained in the equal-time theory. We calculate the vacuum expectation value as a function of the coupling constant in the broken phase both numerically and analytically using the δ expansion. We find two equivalent broken phases. Finally we show that the energy levels of the system have the expected behavior for the broken phase

  9. The effects of dynamic lighting on office workers : first-year results of a longitudinal field study

    NARCIS (Netherlands)

    Kort, de Y.A.W.; Smolders, K.C.H.J.; Kort, Y.A.W.; et al, xx

    2009-01-01

    Dynamic lighting is designed to have positive effects on wellbeing and performance. In a field experiment we tested whether these effects are detectable and stable over time when employed in actual work settings. This 2-year study consists of two tranches, one following a monthly alternating

  10. Light-induced space-charge fields for the structuration of dielectric materials; Lichtinduzierte Raumladungsfelder zur Strukturierung dielektrischer Materialien

    Energy Technology Data Exchange (ETDEWEB)

    Eggert, H A

    2006-11-15

    Light-induced space-charge fields in lithium-niobate crystals are used for patterning of dielectric materials. This includes tailored ferroelectric domains in the bulk of the crystal, different sorts of micro and nanoparticles on a crystal surface, as well as poling of electrooptic chromophores. A stochastical model is introduced, which can describe the spatial inhomogeneous domain inversion. (orig.)

  11. May the variable magnetic field and pulse red light induce synergy effects in respiratory burst of neutrophils in vitro?

    International Nuclear Information System (INIS)

    Nawrocka - Bogusz, H; Jaroszyk, F

    2011-01-01

    We investigated the effect of the red light (R) (630 nm), magnetic field (MF) and magnetic field combined with the red light (MF+R) upon reactive oxygen species (ROS) production by neutrophils in vitro. The object of the research was hydrogen peroxide (H 2 O 2 ) formation during neutrophils respiratory burst or within steady-state. Blood from healthy volunteers was used for the purpose of the study. Flow cytometry method, using transformation of DCFH-DA (2'7'-dichlorofluorescin diacetate) to the fluorescent DCF (2'7'-dichlorofluorescin), was used for estimation of hydrogen peroxide production. The variable magnetic field of ELF range of the mean induction equals 26.7(μT), the red light at the energy density of 1.17(J/cm 2 ) and their combination were applied for 30 minutes each. The fundamental frequency of pulses was 180÷ 195 Hz. A statistically significant decrease of H 2 O 2 production by neutrophils was observed. The level of the decrease was in the range of 10-30% and was dependent on the kind of applied physical factors and whether neutrophils were stimulated or not. The observation showed that the variable magnetic field combined with red light do not induce the synergy effect.

  12. Direct characterization of ultraviolet-light-induced refractive index structures by scanning near-field optical microscopy

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Madsen, S.; Hvam, Jørn Märcher

    1998-01-01

    We have applied a reflection scanning near-field optical microscope to directly probe ultraviolet (UV)-light-induced refractive index structures in planar glass samples. This technique permits direct comparison between topography and refractive index changes (10(-5)-10(-3)) with submicrometer...

  13. Structural stability of naphthyl end-capped oligothiophenes in organic field-effect transistors measured by grazing-incidence X-ray diffraction in operando

    DEFF Research Database (Denmark)

    Huss-Hansen, Mathias K.; Lauritzen, Andreas E.; Bikondoa, Oier

    2017-01-01

    We report on microstructural durability of 5,5′-bis(naphth-2-yl)-2,2′-bithiophene (NaT2) in organic field-effect transistors (OFETs) in operando monitored by grazing-incidence X-ray diffraction (GIXRD). NaT2 maintains its monoclinic bulk motif in operating OFETs with a=20.31±0.06 Å, b=6.00±0.01 Å...

  14. Hybrid photonic-plasmonic near-field probe for efficient light conversion into the nanoscale hot spot.

    Science.gov (United States)

    Koshelev, Alexander; Munechika, Keiko; Cabrini, Stefano

    2017-11-01

    In this Letter, we present a design and simulations of the novel hybrid photonic-plasmonic near-field probe. Near-field optics is a unique imaging tool that provides optical images with resolution down to tens of nanometers. One of the main limitations of this technology is its low light sensitivity. The presented hybrid probe solves this problem by combining a campanile plasmonic probe with the photonic layer, consisting of the diffractive optic element (DOE). The DOE is designed to match the plasmonic field at the broad side of the campanile probe with the fiber mode. This makes it possible to optimize the size of the campanile tip to convert light efficiently into the hot spot. The simulations show that the hybrid probe is ∼540 times more efficient compared with the conventional campanile on average in the 600-900 nm spectral range.

  15. Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study

    Directory of Open Access Journals (Sweden)

    Lameese D. Akacem

    2016-11-01

    Full Text Available Light exposure and sleep timing are two factors that influence inter-individual variability in the timing of the human circadian clock. The aim of this study was to quantify the degree to which evening light exposure predicts variance in circadian timing over and above bedtime alone in preschool children. Participants were 21 children ages 4.5–5.0 years (4.7±0.2 years; 9 females. Children followed their typical sleep schedules for 4 days during which time they wore a wrist actigraph to assess sleep timing and a pendant light meter to measure minute-by-minute illuminance levels in lux. On the 5th day, children participated in an in-home dim-light melatonin onset (DLMO assessment. Light exposure in the 2 h before bedtime was averaged and aggregated across the 4 nights preceding the DLMO assessment. Mean DLMO and bedtime were 19:22±01:04 and 20:07±00:46, respectively. Average evening light exposure was 710.1±1418.2 lux. Children with later bedtimes (lights-off time had more delayed melatonin onset times (r=0.61, p=0.002. Evening light exposure was not independently associated with DLMO (r=0.32, p=0.08; however, a partial correlation between evening light exposure and DLMO when controlling for bedtime yielded a positive correlation (r=0.46, p=0.02. Bedtime explained 37.3% of the variance in the timing of DLMO, and evening light exposure accounted for an additional 13.3% of the variance. These findings represent an important step in understanding factors that influence circadian phase in preschool-age children and have implications for understanding a modifiable pathway that may underlie late sleep timing and the development of evening settling problems in early childhood.

  16. Coherence holography by achromatic 3-D field correlation of generic thermal light with an imaging Sagnac shearing interferometer.

    Science.gov (United States)

    Naik, Dinesh N; Ezawa, Takahiro; Singh, Rakesh Kumar; Miyamoto, Yoko; Takeda, Mitsuo

    2012-08-27

    We propose a new technique for achromatic 3-D field correlation that makes use of the characteristics of both axial and lateral magnifications of imaging through a common-path Sagnac shearing interferometer. With this technique, we experimentally demonstrate, for the first time to our knowledge, 3-D image reconstruction of coherence holography with generic thermal light. By virtue of the achromatic axial shearing implemented by the difference in axial magnifications in imaging, the technique enables coherence holography to reconstruct a 3-D object with an axial depth beyond the short coherence length of the thermal light.

  17. Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aiken, Allison [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, Larry K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Andrew [Aerodyne Research, Inc., Billerica, MA (United States); Gorkowski, Kyle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-01

    We deployed Aerodyne Research Inc.’s first Cavity Attenuated Phase Shift extinction (CAPS PMex) monitor (built by Aerodyne) that measures light extinction by using a visible-light-emitting diode (LED) as a light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector in Cape Cod in 2012/13 for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Two-Column Aerosol Project (TCAP). The efficacy of this instrument is based on the fact that aerosols are broadband scatterers and absorbers of light. The input LED is square-wave modulated and passed through the sample cell that distorts it due to exponential decay by aerosol light absorption and scattering; this is measured at the detector. The amount of phase shift of the light at the detector is used to determine the light extinction. This extinction measurement provides an absolute value, requiring no calibration. The goal was to compare the CAPS performance with direct measurements of absorption with ARM’s baseline photoacoustic soot spectrometer (PASS-3) and nephelometer instruments to evaluate its performance.

  18. Effects of shock waves, ultraviolet light, and electric fields from pulsed discharges in water on inactivation of Escherichia coli.

    Science.gov (United States)

    Sun, Bing; Xin, Yanbin; Zhu, Xiaomei; Gao, Zhiying; Yan, Zhiyu; Ohshima, Takayuki

    2018-04-01

    In this work, the bacterial inactivation effects of shock waves, ultraviolet (UV) light, and electric field produced by high-voltage pulsed discharge in liquid with needle-plate configurations were studied. The contributions of each effect on the bacterial killing ratio in the discharge process were obtained individually by modifying reactor type and usage of glass, quartz, and black balloons. The results showed that the location from the discharge center axis significantly influenced the effects of shock waves and electric fields, although the effect of UV light was not affected by the location in the reactor. The effects of shock waves and electric fields were improved by decreasing the distance from the discharge center axis. Under this experimental condition, the effects of shock waves, UV light, and electric fields produced by discharges on bacterial inactivation were approximately 36.1%, 30.8%, 12.7%, respectively. Other contributions seemed to be due to activated species. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Spontaneous symmetry breaking of (1+1)-dimensional φ4 theory in light-front field theory. II

    International Nuclear Information System (INIS)

    Pinsky, S.S.; van de Sande, B.

    1994-01-01

    We discuss spontaneous symmetry breaking of (1+1)-dimensional φ 4 theory in light-front field theory using a Tamm-Dancoff truncation. We show that, even though light-front field theory has a simple vacuum state which is an eigenstate of the full Hamiltonian, the field can develop a nonzero vacuum expectation value. This occurs because the zero mode of the field must satisfy an operator-valued constraint equation. In the context of (1+1)-dimensional φ 4 theory we present solutions to the constraint equation using a Tamm-Dancoff truncation to a finite number of particles and modes. We study the behavior of the zero mode as a function of coupling and Fock space truncation. The zero mode introduces new interactions into the Hamiltonian which breaks the Z 2 symmetry of the theory when the coupling is stronger than the critical coupling. We investigate the energy spectrum in the symmetric and broken phases, show that the theory does not break down in the vicinity of the critical coupling, and discuss the connection to perturbation theory. Finally, we study the spectrum of the field φ and show that, in the broken phase, the field is localized away from φ=0 as one would expect from equal-time calculations. We explicitly show that tunneling occurs

  20. Free-Free Transitions of e-H System Inside a Dense Plasma Irradiated by a Laser Field at Very Low Incident Electron Energies

    Science.gov (United States)

    Bhatia, A. K.; Sinha, C.

    2012-01-01

    The free-free transition is studied for an electron-hydrogen in the ground state at low incident energies in the presence of an external homogenous, monochromatic, and linearly polarized laser-field inside a hot dense plasma.The effect of plasma screening is considered in the Debye-Huckel approximation. The calculations are performed in the soft photon limit, assuming that the plasma frequency is much higher than the laser frequency. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. The space part of the scattering wave function for the electron is solved numerically by taking into account the electron exchange. The laser-assisted differential and total cross sections are calculated for single-photon absorption /emission and no photon exchange in the soft photon limit, the laser intensity being much less than the atomic field intensity. The calculations have been carried out for various values of Debye parameter, ranging from 0.005 to 0.12. A strong suppression is noted in the laser-assisted cross sections as compared to the field-free situation. A significant difference is noted for the singlet and triplet cross sections. The suppression is much more in the triplet states.

  1. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    Directory of Open Access Journals (Sweden)

    Njeh Christopher F

    2012-03-01

    Full Text Available Abstract Background The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. Method A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID or computed radiography (CR. We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Results Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. Conclusion The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence.

  2. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    International Nuclear Information System (INIS)

    Njeh, Christopher F; Caroprese, Blas; Desai, Pushkar

    2012-01-01

    The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID) or computed radiography (CR). We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence

  3. A novel autonomous real-time position method based on polarized light and geomagnetic field

    OpenAIRE

    Wang, Yinlong; Chu, Jinkui; Zhang, Ran; Wang, Lu; Wang, Zhiwen

    2015-01-01

    Many animals exploit polarized light in order to calibrate their magnetic compasses for navigation. For example, some birds are equipped with biological magnetic and celestial compasses enabling them to migrate between the Western and Eastern Hemispheres. The Vikings' ability to derive true direction from polarized light is also widely accepted. However, their amazing navigational capabilities are still not completely clear. Inspired by birds' and Vikings' ancient navigational skills. Here we...

  4. WOW: light print, light propel, light point

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Bañas, Andrew Rafael; Aabo, Thomas

    2012-01-01

    anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light...... propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation...

  5. Per-point and per-field contextual classification of multipolarization and multiple incidence angle aircraft L-band radar data

    Science.gov (United States)

    Hoffer, Roger M.; Hussin, Yousif Ali

    1989-01-01

    Multipolarized aircraft L-band radar data are classified using two different image classification algorithms: (1) a per-point classifier, and (2) a contextual, or per-field, classifier. Due to the distinct variations in radar backscatter as a function of incidence angle, the data are stratified into three incidence-angle groupings, and training and test data are defined for each stratum. A low-pass digital mean filter with varied window size (i.e., 3x3, 5x5, and 7x7 pixels) is applied to the data prior to the classification. A predominately forested area in northern Florida was the study site. The results obtained by using these image classifiers are then presented and discussed.

  6. Incidence and outcome of patients starting renal replacement therapy for end-stage renal disease due to multiple myeloma or light-chain deposit disease: an ERA-EDTA Registry study

    DEFF Research Database (Denmark)

    Tsakiris, D.J.; Stel, V.S.; Finne, P.

    2010-01-01

    Background. Information on demographics and survival of patients starting renal replacement therapy (RRT) for end-stage renal disease (ESRD) due to multiple myeloma (MM) or light-chain deposit disease (LCDD) is scarce. The aim of this study was to describe the incidence, characteristics, causes...... causes (non-MM) was observed overtime. Patient survival on RRT was examined, unadjusted and adjusted for age and gender. Results. Of the 159 637 patients on RRT, 2453 (1.54%) had MM or LCDD. The incidence of RRT for ESRD due to MM or LCDD, adjusted for age and gender, increased from 0.70 pmp in 1986...

  7. Addendum. Relation for the Light Absorption in the Presence of Gravitation Field

    OpenAIRE

    R.Vlokh; M.Kostyrko

    2005-01-01

    We argue for the validity of relation for electromagnetic wave electric field derived by us earlier. It includes an imaginary part responsible for the absorption induced by gravitation field of spherically symmetric mass.

  8. Effective Responder Communication Improves Efficiency and Psychological Outcomes in a Mass Decontamination Field Experiment: Implications for Public Behaviour in the Event of a Chemical Incident

    Science.gov (United States)

    Carter, Holly; Drury, John; Amlôt, Richard; Rubin, G. James; Williams, Richard

    2014-01-01

    The risk of incidents involving mass decontamination in response to a chemical, biological, radiological, or nuclear release has increased in recent years, due to technological advances, and the willingness of terrorists to use unconventional weapons. Planning for such incidents has focused on the technical issues involved, rather than on psychosocial concerns. This paper presents a novel experimental study, examining the effect of three different responder communication strategies on public experiences and behaviour during a mass decontamination field experiment. Specifically, the research examined the impact of social identity processes on the relationship between effective responder communication, and relevant outcome variables (e.g. public compliance, public anxiety, and co-operative public behaviour). All participants (n = 111) were asked to visualise that they had been involved in an incident involving mass decontamination, before undergoing the decontamination process, and receiving one of three different communication strategies: 1) ‘Theory-based communication’: Health-focused explanations about decontamination, and sufficient practical information; 2) ‘Standard practice communication’: No health-focused explanations about decontamination, sufficient practical information; 3) ‘Brief communication’: No health-focused explanations about decontamination, insufficient practical information. Four types of data were collected: timings of the decontamination process; observational data; and quantitative and qualitative self-report data. The communication strategy which resulted in the most efficient progression of participants through the decontamination process, as well as the fewest observations of non-compliance and confusion, was that which included both health-focused explanations about decontamination and sufficient practical information. Further, this strategy resulted in increased perceptions of responder legitimacy and increased

  9. Effective responder communication improves efficiency and psychological outcomes in a mass decontamination field experiment: implications for public behaviour in the event of a chemical incident.

    Science.gov (United States)

    Carter, Holly; Drury, John; Amlôt, Richard; Rubin, G James; Williams, Richard

    2014-01-01

    The risk of incidents involving mass decontamination in response to a chemical, biological, radiological, or nuclear release has increased in recent years, due to technological advances, and the willingness of terrorists to use unconventional weapons. Planning for such incidents has focused on the technical issues involved, rather than on psychosocial concerns. This paper presents a novel experimental study, examining the effect of three different responder communication strategies on public experiences and behaviour during a mass decontamination field experiment. Specifically, the research examined the impact of social identity processes on the relationship between effective responder communication, and relevant outcome variables (e.g. public compliance, public anxiety, and co-operative public behaviour). All participants (n = 111) were asked to visualise that they had been involved in an incident involving mass decontamination, before undergoing the decontamination process, and receiving one of three different communication strategies: 1) 'Theory-based communication': Health-focused explanations about decontamination, and sufficient practical information; 2) 'Standard practice communication': No health-focused explanations about decontamination, sufficient practical information; 3) 'Brief communication': No health-focused explanations about decontamination, insufficient practical information. Four types of data were collected: timings of the decontamination process; observational data; and quantitative and qualitative self-report data. The communication strategy which resulted in the most efficient progression of participants through the decontamination process, as well as the fewest observations of non-compliance and confusion, was that which included both health-focused explanations about decontamination and sufficient practical information. Further, this strategy resulted in increased perceptions of responder legitimacy and increased identification with

  10. Effective responder communication improves efficiency and psychological outcomes in a mass decontamination field experiment: implications for public behaviour in the event of a chemical incident.

    Directory of Open Access Journals (Sweden)

    Holly Carter

    Full Text Available The risk of incidents involving mass decontamination in response to a chemical, biological, radiological, or nuclear release has increased in recent years, due to technological advances, and the willingness of terrorists to use unconventional weapons. Planning for such incidents has focused on the technical issues involved, rather than on psychosocial concerns. This paper presents a novel experimental study, examining the effect of three different responder communication strategies on public experiences and behaviour during a mass decontamination field experiment. Specifically, the research examined the impact of social identity processes on the relationship between effective responder communication, and relevant outcome variables (e.g. public compliance, public anxiety, and co-operative public behaviour. All participants (n = 111 were asked to visualise that they had been involved in an incident involving mass decontamination, before undergoing the decontamination process, and receiving one of three different communication strategies: 1 'Theory-based communication': Health-focused explanations about decontamination, and sufficient practical information; 2 'Standard practice communication': No health-focused explanations about decontamination, sufficient practical information; 3 'Brief communication': No health-focused explanations about decontamination, insufficient practical information. Four types of data were collected: timings of the decontamination process; observational data; and quantitative and qualitative self-report data. The communication strategy which resulted in the most efficient progression of participants through the decontamination process, as well as the fewest observations of non-compliance and confusion, was that which included both health-focused explanations about decontamination and sufficient practical information. Further, this strategy resulted in increased perceptions of responder legitimacy and increased

  11. Coherent light from E-field induced quantum coupling of exciton states in superlattice-like quantum wells

    DEFF Research Database (Denmark)

    Lyssenko, V. G.; Østergaard, John Erland; Hvam, Jørn Märcher

    1999-01-01

    Summary form only given. We focus on the ability to control the electronic coupling in coupled quantum wells with external E-fields leading to a strong modification of the coherent light emission, in particular at a bias where a superlattice-like miniband is formed. More specifically, we investig......Summary form only given. We focus on the ability to control the electronic coupling in coupled quantum wells with external E-fields leading to a strong modification of the coherent light emission, in particular at a bias where a superlattice-like miniband is formed. More specifically, we...... investigate a MBE-grown GaAs sample with a sequence of 15 single quantum wells having a successive increase of 1 monolayer in width ranging from 62 A to 102 A and with AlGaAs barriers of 17 Å....

  12. Effect of AC magnetic fields on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ager, D.D.; Radul, J.A.

    1994-01-01

    The ability of 60-Hz magnetic fields to induce genetic damage in Saccharomyces cerevisiae was studied. The frequencies of induced mutation, gene conversion, and reciprocal mitotic crossing over were measured for exposures to 1-millitesla magnetic fields alone or in combination with various preliminary exposures to 254-nm ultraviolet light at intensities of 2-50 J/m 2 . These experiments were performed using a repair-proficient strain as well as a strain incapable of excising ultraviolet-induced thymine dimers. Magnetic field exposures did not induce mutation, gene conversion, or reciprocal mitotic crossing over in either of these strains, nor did the fields influence the frequencies of ultraviolet-induced genetic events. 32 refs., 4 tabs

  13. Light-front quantized field theory (an introduction): spontaneous symmetry breaking. Phase transition in φ4 theory

    International Nuclear Information System (INIS)

    Srivastava, Prem P.

    1994-01-01

    The Dirac procedure is used to construct the Hamiltonian formulation of the scalar field theory on the light-front. The theory is quantized and the mechanism of the spontaneous symmetry breaking in the front form and the instant form dynamics are compared. The phase transition in (φ 4 )2 theory is also discussed and found to be of the second order. (author). 36 refs

  14. Visualizing light with electrons

    Science.gov (United States)

    Fitzgerald, J. P. S.; Word, R. C.; Koenenkamp, R.

    2014-03-01

    In multiphoton photoemission electron microscopy (nP-PEEM) electrons are emitted from surfaces at a rate proportional to the surface electromagnetic field amplitude. We use 2P-PEEM to give nanometer scale visualizations of light of diffracted and waveguide fields around various microstructures. We use Fourier analysis to determine the phase and amplitude of surface fields in relation to incident light from the interference patterns. To provide quick and intuitive simulations of surface fields, we employ two dimensional Fresnel-Kirchhoff integration, a technique based on freely propagating waves and Huygens' principle. We find generally good agreement between simulations and experiment. Additionally diffracted wave simulations exhibit greater phase accuracy, indicating that these waves are well represented by a two dimensional approximation. The authors gratefully acknowledge funding of this research by the US-DOE Basic Science Office under Contract DE-FG02-10ER46406.

  15. Quantitative evaluation of a handheld light microscope for field diagnosis of soil-transmitted helminth infection.

    Science.gov (United States)

    Bogoch, Isaac I; Andrews, Jason R; Speich, Benjamin; Ame, Shaali M; Ali, Said M; Stothard, J Russell; Utzinger, Jürg; Keiser, Jennifer

    2014-12-01

    We evaluated the Newton Nm1, a commercially available handheld light microscope and compared it with conventional light microscopy for the diagnosis of soil-transmitted helminth infections. A total of 91 Kato-Katz thick smears were examined by experienced microscopists and helminth eggs were counted and expressed as eggs per gram of stool (EPG). Mean egg counts were significantly higher with the conventional light microscope (5,190 EPG versus 2,386 EPG for Ascaris lumbricoides; 826 versus 456 for Trichuris trichiura; both P Newton Nm1 microscope may be a useful tool for the detection and quantification of soil-transmitted helminth infection in clinical, epidemiologic, and public health settings. © The American Society of Tropical Medicine and Hygiene.

  16. Light-pollution measurement with the Wide-field all-sky image analyzing monitoring system

    Science.gov (United States)

    Vítek, S.

    2017-07-01

    The purpose of this experiment was to measure light pollution in the capital of Czech Republic, Prague. As a measuring instrument is used calibrated consumer level digital single reflex camera with IR cut filter, therefore, the paper reports results of measuring and monitoring of the light pollution in the wavelength range of 390 - 700 nm, which most affects visual range astronomy. Combining frames of different exposure times made with a digital camera coupled with fish-eye lens allow to create high dynamic range images, contain meaningful values, so such a system can provide absolute values of the sky brightness.

  17. Light Bending by a Coulomb Field and the Aichelburg-Sexl Ultraboost

    Science.gov (United States)

    Kozyulin, M. V.; Silagadze, Z. K.

    2011-01-01

    Gravitational light deflection, predicted by general relativity, is a fascinating phenomenon with numerous important applications in astronomy, astrophysics and cosmology. At first sight, there is no analogous effect in electrodynamics because Maxwell's equations are linear and, therefore, a photon does not interact with the electromagnetic field…

  18. Exploring the impact of natural light exposure on sleep of healthy older adults: a field study

    NARCIS (Netherlands)

    Aarts, M.P.J.; Stapel, J.C.; Schoutens, A.M.C.; van Hoof, J.

    Studies among people with dementia demonstrated that the sleep quality and rhythm improves significantly when people are exposed to ambient bright light. Since almost half of the healthy older people also indicate to suffer from chronic sleep disorders, the question arises whether ambient bright

  19. Photosynthesis, light use efficiency, and yield of reduced-chlorophyll soybean mutants in field conditions

    Science.gov (United States)

    Reducing chlorophyll (chl) content may improve the conversion efficiency of absorbed radiation into biomass (ec) and therefore yield in dense monoculture crops by improving light penetration and distribution within the canopy. Modeling suggests that reducing chl content may also reduce leaf temperat...

  20. Natural light exposure, healthy elderly people and sleep : a field study

    NARCIS (Netherlands)

    Aarts, M.P.J.; Schoutens, A.M.C.; Stapel, J.C.

    2006-01-01

    Among 14 independently living, mobile and healthy elderly people in The Netherlands was conducted to see whether exposure duration of high intensity, natural, light is related to sleep quality, and more general the amplitude of the sleep-wake cycle. The elderly wore for 5 consecutive days in summer

  1. Exploring the impact of natural light exposure on sleep of healthy older adults: A field study

    NARCIS (Netherlands)

    Aarts, M.P.J.; Stapel, J.C.; Schoutens, A.M.C.; Hoof, J. van

    2018-01-01

    Studies among people with dementia demonstrated that the sleep quality and rhythm improves significantly when people are exposed to ambient bright light. Since almost half of the healthy older people also indicate to suffer from chronic sleep disorders, the question arises whether ambient bright

  2. Evaluation of the different levels of variability in the underwater light field of a shallow estuary

    NARCIS (Netherlands)

    Schubert, H.; Sagert, S.; Forster, R.M.

    2001-01-01

    The underwater light climate of a shallow estuary located at the southern coast of the Baltic Sea has been investigated, with special emphasis on the spectral irradiance composition and on short-term irradiance fluctuations caused by vertical mixing and wave focussing. The inherent optical

  3. First Transmitted Hyperspectral Light Measurements and Cloud Properties from Recent Field Campaign Sampling Clouds Under Biomass Burning Aerosol

    Science.gov (United States)

    Leblanc, S.; Redemann, Jens; Shinozuka, Yohei; Flynn, Connor J.; Segal Rozenhaimer, Michal; Kacenelenbogen, Meloe Shenandoah; Pistone, Kristina Marie Myers; Schmidt, Sebastian; Cochrane, Sabrina

    2016-01-01

    We present a first view of data collected during a recent field campaign aimed at measuring biomass burning aerosol above clouds from airborne platforms. The NASA ObseRvations of CLouds above Aerosols and their intEractionS (ORACLES) field campaign recently concluded its first deployment sampling clouds and overlying aerosol layer from the airborne platform NASA P3. We present results from the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR), in conjunction with the Solar Spectral Flux Radiometers (SSFR). During this deployment, 4STAR sampled transmitted solar light either via direct solar beam measurements and scattered light measurements, enabling the measurement of aerosol optical thickness and the retrieval of information on aerosol particles in addition to overlying cloud properties. We focus on the zenith-viewing scattered light measurements, which are used to retrieve cloud optical thickness, effective radius, and thermodynamic phase of clouds under a biomass burning layer. The biomass burning aerosol layer present above the clouds is the cause of potential bias in retrieved cloud optical depth and effective radius from satellites. We contrast the typical reflection based approach used by satellites to the transmission based approach used by 4STAR during ORACLES for retrieving cloud properties. It is suspected that these differing approaches will yield a change in retrieved properties since light transmitted through clouds is sensitive to a different cloud volume than reflected light at cloud top. We offer a preliminary view of the implications of these differences in sampling volumes to the calculation of cloud radiative effects (CRE).

  4. Inelastic electron and light scattering from the elementary electronic excitations in quantum wells: Zero magnetic field

    Directory of Open Access Journals (Sweden)

    Manvir S. Kushwaha

    2012-09-01

    Full Text Available The most fundamental approach to an understanding of electronic, optical, and transport phenomena which the condensed matter physics (of conventional as well as nonconventional systems offers is generally founded on two experiments: the inelastic electron scattering and the inelastic light scattering. This work embarks on providing a systematic framework for the theory of inelastic electron scattering and of inelastic light scattering from the electronic excitations in GaAs/Ga1−xAlxAs quantum wells. To this end, we start with the Kubo's correlation function to derive the generalized nonlocal, dynamic dielectric function, and the inverse dielectric function within the framework of Bohm-Pines’ random-phase approximation. This is followed by a thorough development of the theory of inelastic electron scattering and of inelastic light scattering. The methodological part is then subjected to the analytical diagnoses which allow us to sense the subtlety of the analytical results and the importance of their applications. The general analytical results, which know no bounds regarding, e.g., the subband occupancy, are then specified so as to make them applicable to practicality. After trying and testing the eigenfunctions, we compute the density of states, the Fermi energy, the full excitation spectrum made up of intrasubband and intersubband – single-particle and collective (plasmon – excitations, the loss functions for all the principal geometries envisioned for the inelastic electron scattering, and the Raman intensity, which provides a measure of the real transitions induced by the (laser probe, for the inelastic light scattering. It is found that the dominant contribution to both the loss peaks and the Raman peaks comes from the collective (plasmon excitations. As to the single-particle peaks, the analysis indicates a long-lasting lack of quantitative comparison between theory and experiments. It is inferred that the inelastic electron

  5. Mixing of photons with light pseudoscalars in time-dependent magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Arias, Paola; Arza, Ariel; Gamboa, Jorge [Universidad de Santiago de Chile, Departmento de Fisica, Santiago (Chile)

    2016-11-15

    The effects of an external time-dependent magnetic field in the conversion probability of photon- to axion-like particles are studied. Our findings show that for a certain time regime, the amplitude of the produced axion-like field can be enlarged with respect to the static case, thus enhancing the probability of conversion. (orig.)

  6. Chiral magnetic effect of light

    Science.gov (United States)

    Hayata, Tomoya

    2018-05-01

    We study a photonic analog of the chiral magnetic (vortical) effect. We discuss that the vector component of magnetoelectric tensors plays a role of "vector potential," and its rotation is understood as "magnetic field" of a light. Using the geometrical optics approximation, we show that "magnetic fields" cause an anomalous shift of a wave packet of a light through an interplay with the Berry curvature of photons. The mechanism is the same as that of the chiral magnetic (vortical) effect of a chiral fermion, so that we term the anomalous shift "chiral magnetic effect of a light." We further study the chiral magnetic effect of a light beyond geometric optics by directly solving the transmission problem of a wave packet at a surface of a magnetoelectric material. We show that the experimental signal of the chiral magnetic effect of a light is the nonvanishing of transverse displacements for the beam normally incident to a magnetoelectric material.

  7. The stimulatory effects of caffeine with oseltamivir (Tamiflu) on light-dark behavior and open-field behavior in mice.

    Science.gov (United States)

    Uchiyama, Hidemori; Toda, Akihisa; Imoto, Masumi; Nishimura, Satoko; Kuroki, Hiroaki; Soeda, Shinji; Shimeno, Hiroshi; Watanabe, Shigenori; Eyanagi, Reiko

    2010-01-22

    Abnormal behaviors and death associated with the use of oseltamivir (Tamiflu) have emerged as a major issue in influenza patients taking the drug. Here, we investigated the mechanisms underlying the effects of oseltamivir on the behavior of mice using light-dark and open-field preference tests. Oseltamivir (75 and 150 mg/kg, intraperitoneally (i.p.)) alone affected neither time spent in the open area in the light-dark preference test nor ambulation in the open-field test at 2h post-injection. However, a non-selective adenosine A(1)/A(2) receptor antagonist, caffeine (10mg/kg, i.p.) in combination with oseltamivir (150 mg/kg, i.p.) increased time spent in the open area in the light-dark preference test. This enhancement was not inhibited by a benzodiazepine receptor antagonist, flumazenil (10-20mg/kg, subcutaneously (s.c.)). Enhancement of ambulation in the open-field test was also observed when caffeine (10mg/kg, i.p.) was combined with oseltamivir (150 mg/kg, i.p.). This enhancement was inhibited by a dopamine D(2) receptor antagonist, haloperidol (0.1mg/kg, s.c.). Furthermore, an adenosine A(2) receptor antagonist, SCH58261 (3mg/kg, i.p.) in combination with oseltamivir (150 mg/kg, i.p.) increased ambulation in the open-field test, while an adenosine A(1) receptor antagonist, DPCPX (1-3mg/kg, i.p.) did not. These findings suggest that the actions of oseltamivir may involve the dopamine and adenosine systems. Our findings suggest that due to the interaction between central blockade of adenosine A(2) receptors by caffeine, and oseltamivir-induced behavioral changes, patients being treated with oseltamivir should be closely monitored. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  8. Light-front quantized field theory: (an introduction). Spontaneous symmetry breaking. Phase transition in φ4 theory

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1993-01-01

    The field theory quantized on the light-front is compared with the conventional equal-time quantized theory. The arguments based on the micro causality principle would imply that the light-front field theory may become nonlocal with respect to the longitudinal coordinate even though the corresponding equal-time formulation is local. This is found to be the case for the scalar theory. The conventional instant form theory is sometimes required to be constrained by invoking external physical considerations; the analogous conditions seem to be already built in the theory on the light-front. In spite of the different mechanisms of the spontaneous symmetry breaking in the two forms of dynamics they result in the same physical content. The phase transition in (φ 4 ) 2 theory is also discussed. The symmetric vacuum state for vanishingly small couplings is found to turn into an unstable symmetric one when the coupling is increased and may result in a phase transition of the second order in contrast to the first order transition concluded from the usual variational methods. (author)

  9. Light yield as a function of gas pressure and electric field in gas scintillation proportional counters

    International Nuclear Information System (INIS)

    Favata, F.; Smith, A.; Bavdaz, M.; Kowalski, T.Z.

    1990-01-01

    We have investigated the dependence of the scintillation light output for Xe on gas pressure in the range 0.14-1.4 bar, using a gas scintillation proportional counter, in different experimental configurations. We have compared our work with that of previous workers, and have shown that both our results and the results of previous authors are compatible with the intrinsic light output being independent of gas pressure, with any observed dependence being a pure experimental effect due to the spectral response of the various UV detectors used. We also use our experimental data for determining the ratio between the cross section of the Xe 2 ** +Xe→Xe 2 * +Xe reaction and the rate of the Xe 2 ** →2Xe+γ UV reaction. (orig.)

  10. Angular momentum conservation law in light-front quantum field theory

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Kelly Yu-Ju; Brodsky, Stanley J.; /SLAC /Stanford U.

    2017-03-01

    We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3 , the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.

  11. Spectral absorption of unpolarized light through nano-materials in the absence of a magnetic field

    Directory of Open Access Journals (Sweden)

    Luminosu I.

    2008-01-01

    Full Text Available A study of optical properties, such as light absorption, of a colloidal nano-material, provides information on the biphasic, solid - liquid system microstructure. The nano-material under study is a magnetic liquid (ferrofluid. The disperser agent is petroleum mineral oil and the dispersed material is a brown spar powder (nano-particles. The stabilizer is oleic acid. Light absorption through ferrofluid samples reveals the tendency of solid particles in a colloidal solution to form aggregates. The paper emphasizes the linear dependence between the spectral absorption coefficient, concentration and wavelength. The aggregates cause deviations of the extinction coefficient from values according to the Bouger-Lambert-Beer law. Fe3O4 aggregates sized 58.76 nm are formed in the system. The average number of nano-particles forming aggregates is 6. The magnetic liquid to be studied is secure stable and, thus, trustful in technological and biological applications.

  12. Portable light-emitting diode-based photometer with one-shot optochemical sensors for measurement in the field.

    Science.gov (United States)

    Palma, A J; Ortigosa, J M; Lapresta-Fernández, A; Fernández-Ramos, M D; Carvajal, M A; Capitán-Vallvey, L F

    2008-10-01

    This report describes the electronics of a portable, low-cost, light-emitting diode (LED)-based photometer dedicated to one-shot optochemical sensors. Optical detection is made through a monolithic photodiode with an on-chip single-supply transimpedance amplifier that reduces some drawbacks such as leakage currents, interferences, and parasitic capacitances. The main instrument characteristics are its high light source stability and thermal correction. The former is obtained by means of the optical feedback from the LED polarization circuit, implementing a pseudo-two light beam scheme from a unique light source with a built-in beam splitter. The feedback loop has also been used to adjust the LED power in several ranges. Moreover, the low-thermal coefficient achieved (-90 ppm/degrees C) is compensated by thermal monitoring and calibration function compensation in the digital processing. The hand-held instrument directly gives the absorbance ratio used as the analytical parameter and the analyte concentration after programming the calibration function in the microcontroller. The application of this photometer for the determination of potassium and nitrate, using one-shot sensors with ionophore-based chemistries is also demonstrated, with a simple analytical methodology that shortens the analysis time, eliminating some calibrating solutions (HCl, NaOH, and buffer). Therefore, this compact instrument is suitable for real-time analyte determination and operation in the field.

  13. Light-absorbing Aerosol Properties in the Kathmandu Valley during SusKat-ABC Field Campaign

    Science.gov (United States)

    Kim, S.; Yoon, S.; Kim, J.; Cho, C.; Jung, J.

    2013-12-01

    Light-absorbing aerosols, such as black carbon (BC), are major contributors to the atmospheric heating and the reduction of solar radiation reaching at the earth's surface. In this study, we investigate light-absorption and scattering properties of aerosols (i.e., BC mass concentration, aerosol solar-absorption/scattering efficiency) in the Kathmandu valley during Sustainable atmosphere for the Kathmandu valley (SusKat)-ABC campaign, from December 2012 to February 2013. Kathmandu City is among the most polluted cities in the world. However, there are only few past studies that provide basic understanding of air pollution in the Kathmandu Valley, which is not sufficient for designing effective mitigation measures (e.g., technological, financial, regulatory, legal and political measures, planning strategies). A distinct diurnal variation of BC mass concentration with two high peaks observed during wintertime dry monsoon period. BC mass concentration was found to be maximum around 09:00 and 20:00 local standard time (LST). Increased cars and cooking activities including substantial burning of wood and other biomass in the morning and in the evening contributed to high BC concentration. Low BC concentrations during the daytime can be explain by reduced vehicular movement and cooking activities. Also, the developmements of the boundary layer height and mountain-valley winds in the Kathmandu Valley paly a crucial role in the temproal variation of BC mass concentrations. Detailed radiative effects of light-absorbing aerosols will be presented.

  14. A field demonstration of the efficacy of bioremediation to treat oiled shorelines following the Sea Empress incident

    Energy Technology Data Exchange (ETDEWEB)

    Swannell, R.P.J.; Mitchell, D. [AEA Technology Environment, National Environmental Technology Centre, Culham (United Kingdom); Lethbridge, G. [Texaco Ltd., Environment, Health and Safety, Pembroke (GB)] (and others)

    1999-08-01

    Bioremediation was investigated as a method of treating a mixture of Forties Crude Oil and Heavy Fuel Oil stranded on Bullwell Bay, Milford Haven, UK after the grounding of the Sea Empress in 1996. A randomised block design in triplicate was used to test the efficacy of two bioremediation treatments: a weekly application of mineral nutrient dissolved in sea water and a single application of a slow-release fertiliser. Each treatment supplied an equivalent amount of nitrogen and phosphorus. Concentrations of residual hydrocarbon normalised to the biomarker 17{alpha}(H),21{beta}(H)-hopane showed that after two months the oil was significantly (p<0.001) more biodegraded in the treated plots than in the controls. On average, the oil in the nutrient amended plots was 37% more degraded than that found in the controls. There was no evidence that the bioremediation treatment increased the toxicity of the oiled sediment. The results confirm that bioremediation can be used to treat a mixture of crude and heavy fuel oil on a pebble beach. In particular, the data suggest that the application of a slow-release fertiliser alone may be a cost-effective method of treating low-energy, contaminated shorelines after a spill incident. (Author)

  15. A field demonstration of the efficacy of bioremediation to treat oiled shorelines following the Sea Empress incident

    International Nuclear Information System (INIS)

    Swannell, R.P.J.; Mitchell, D.; Lethbridge, G.

    1999-01-01

    Bioremediation was investigated as a method of treating a mixture of Forties Crude Oil and Heavy Fuel Oil stranded on Bullwell Bay, Milford Haven, UK after the grounding of the Sea Empress in 1996. A randomised block design in triplicate was used to test the efficacy of two bioremediation treatments: a weekly application of mineral nutrient dissolved in sea water and a single application of a slow-release fertiliser. Each treatment supplied an equivalent amount of nitrogen and phosphorus. Concentrations of residual hydrocarbon normalised to the biomarker 17α(H),21β(H)-hopane showed that after two months the oil was significantly (p<0.001) more biodegraded in the treated plots than in the controls. On average, the oil in the nutrient amended plots was 37% more degraded than that found in the controls. There was no evidence that the bioremediation treatment increased the toxicity of the oiled sediment. The results confirm that bioremediation can be used to treat a mixture of crude and heavy fuel oil on a pebble beach. In particular, the data suggest that the application of a slow-release fertiliser alone may be a cost-effective method of treating low-energy, contaminated shorelines after a spill incident. (Author)

  16. Near-field light design with colloidal quantum dots for photonics and plasmonics.

    Science.gov (United States)

    Kress, Stephan J P; Richner, Patrizia; Jayanti, Sriharsha V; Galliker, Patrick; Kim, David K; Poulikakos, Dimos; Norris, David J

    2014-10-08

    Colloidal quantum-dots are bright, tunable emitters that are ideal for studying near-field quantum-optical interactions. However, their colloidal nature has hindered their facile and precise placement at desired near-field positions, particularly on the structured substrates prevalent in plasmonics. Here, we use high-resolution electro-hydrodynamic printing (quantum dots on both flat and structured substrates with a few nanometer precision. We also demonstrate that the autofocusing capability of the printing method enables placement of quantum dots preferentially at plasmonic hot spots. We exploit this control and design diffraction-limited photonic and plasmonic sources with arbitrary wavelength, shape, and intensity. We show that simple far-field illumination can excite these near-field sources and generate fundamental plasmonic wave-patterns (plane and spherical waves). The ability to tailor subdiffraction sources of plasmons with quantum dots provides a complementary technique to traditional scattering approaches, offering new capabilities for nanophotonics.

  17. Computational strong-field quantum dynamics. Intense light-matter interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Dieter (ed.) [Rostock Univ. (Germany). Inst. fuer Physik

    2017-09-01

    This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time dependent Schroedinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.

  18. Computational strong-field quantum dynamics. Intense light-matter interactions

    International Nuclear Information System (INIS)

    Bauer, Dieter

    2017-01-01

    This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time dependent Schroedinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.

  19. Computational strong-field quantum dynamics intense light-matter interactions

    CERN Document Server

    2017-01-01

    This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time-dependent Schrödinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi-configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.

  20. Soybean cyst nematode culture collections and field populations from North Carolina and Missouri reveal high incidences of infection by viruses.

    Science.gov (United States)

    Ruark, Casey L; Koenning, Stephen R; Davis, Eric L; Opperman, Charles H; Lommel, Steven A; Mitchum, Melissa G; Sit, Tim L

    2017-01-01

    Five viruses were previously discovered infecting soybean cyst nematodes (SCN; Heterodera glycines) from greenhouse cultures maintained in Illinois. In this study, the five viruses [ScNV, ScPV, ScRV, ScTV, and SbCNV-5] were detected within SCN greenhouse and field populations from North Carolina (NC) and Missouri (MO). The prevalence and titers of viruses in SCN from 43 greenhouse cultures and 25 field populations were analyzed using qRT-PCR. Viral titers within SCN greenhouse cultures were similar throughout juvenile development, and the presence of viral anti-genomic RNAs within egg, second-stage juvenile (J2), and pooled J3 and J4 stages suggests active viral replication within the nematode. Viruses were found at similar or lower levels within field populations of SCN compared with greenhouse cultures of North Carolina populations. Five greenhouse cultures harbored all five known viruses whereas in most populations a mixture of fewer viruses was detected. In contrast, three greenhouse cultures of similar descent to one another did not possess any detectable viruses and primarily differed in location of the cultures (NC versus MO). Several of these SCN viruses were also detected in Heterodera trifolii (clover cyst) and Heterodera schachtii (beet cyst), but not the other cyst, root-knot, or reniform nematode species tested. Viruses were not detected within soybean host plant tissue. If nematode infection with viruses is truly more common than first considered, the potential influence on nematode biology, pathogenicity, ecology, and control warrants continued investigation.

  1. Optical Co-Incidence Gate | Srinivasulu | African Journal of Science ...

    African Journals Online (AJOL)

    The paper explains Optical co-incidence gate, realized using Unijunction transistors (UJT), Light emitting diodes (LED) and Photo-resistors (LDR), which works on 1.8Vdc instead of 3Vdc. The power dissipation of the designed gate is only 3 mW. This optical gate finds application in the field of Mechatronics, Instrumentation ...

  2. Far-field self-focusing and -defocusing radiation behaviors of the electroluminescent light sources due to negative refraction.

    Science.gov (United States)

    Yin, Yu-Feng; Lin, Yen-Chen; Tsai, Tsung-Han; Shen, Yi-Chun; Huang, Jianjang

    2013-01-15

    In recent years, researchers have demonstrated negative refraction theoretically and experimentally by pumping optical power into photonic crystal (PhC) or waveguide structures. The concept of negative refraction can be used to create a perfect lens that focuses an object smaller than the wavelength. By inserting two-dimensional PhCs into the peripheral of a semiconductor light emitting structure, this study presents an electroluminescent device with negative refraction in the visible wavelength range. This approach produces polarization dependent collimation behavior in far-field radiation patterns. The modal dispersion of negative refraction results in strong group velocity modulation, and self-focusing and -defocusing behaviors are apparent from light extraction. This study further verifies experimental results by using theoretic calculations based on equifrequency contours.

  3. Light Robotics

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    Light Robotics - Structure-Mediated Nanobiophotonics covers the latest means of sculpting of both light and matter for achieving bioprobing and manipulation at the smallest scales. The synergy between photonics, nanotechnology and biotechnology spans the rapidly growing field of nanobiophotonics...

  4. Field-controllable Spin-Hall Effect of Light in Optical Crystals: A Conoscopic Mueller Matrix Analysis.

    Science.gov (United States)

    Samlan, C T; Viswanathan, Nirmal K

    2018-01-31

    Electric-field applied perpendicular to the direction of propagation of paraxial beam through an optical crystal dynamically modifies the spin-orbit interaction (SOI), leading to the demonstration of controllable spin-Hall effect of light (SHEL). The electro- and piezo-optic effects of the crystal modifies the radially symmetric spatial variation in the fast-axis orientation of the crystal, resulting in a complex pattern with different topologies due to the symmetry-breaking effect of the applied field. This introduces spatially-varying Pancharatnam-Berry type geometric phase on to the paraxial beam of light, leading to the observation of SHEL in addition to the spin-to-vortex conversion. A wave-vector resolved conoscopic Mueller matrix measurement and analysis provides a first glimpse of the SHEL in the biaxial crystal, identified via the appearance of weak circular birefringence. The emergence of field-controllable fast-axis orientation of the crystal and the resulting SHEL provides a new degree of freedom for affecting and controlling the spin and orbital angular momentum of photons to unravel the rich underlying physics of optical crystals and aid in the development of active photonic spin-Hall devices.

  5. Soybean cyst nematode culture collections and field populations from North Carolina and Missouri reveal high incidences of infection by viruses.

    Directory of Open Access Journals (Sweden)

    Casey L Ruark

    Full Text Available Five viruses were previously discovered infecting soybean cyst nematodes (SCN; Heterodera glycines from greenhouse cultures maintained in Illinois. In this study, the five viruses [ScNV, ScPV, ScRV, ScTV, and SbCNV-5] were detected within SCN greenhouse and field populations from North Carolina (NC and Missouri (MO. The prevalence and titers of viruses in SCN from 43 greenhouse cultures and 25 field populations were analyzed using qRT-PCR. Viral titers within SCN greenhouse cultures were similar throughout juvenile development, and the presence of viral anti-genomic RNAs within egg, second-stage juvenile (J2, and pooled J3 and J4 stages suggests active viral replication within the nematode. Viruses were found at similar or lower levels within field populations of SCN compared with greenhouse cultures of North Carolina populations. Five greenhouse cultures harbored all five known viruses whereas in most populations a mixture of fewer viruses was detected. In contrast, three greenhouse cultures of similar descent to one another did not possess any detectable viruses and primarily differed in location of the cultures (NC versus MO. Several of these SCN viruses were also detected in Heterodera trifolii (clover cyst and Heterodera schachtii (beet cyst, but not the other cyst, root-knot, or reniform nematode species tested. Viruses were not detected within soybean host plant tissue. If nematode infection with viruses is truly more common than first considered, the potential influence on nematode biology, pathogenicity, ecology, and control warrants continued investigation.

  6. Plasmonic nanoparticle chain in a light field: a resonant optical sail.

    Science.gov (United States)

    Albaladejo, Silvia; Sáenz, Juan José; Marqués, Manuel I

    2011-11-09

    Optical trapping and driving of small objects has become a topic of increasing interest in multidisciplinary sciences. We propose to use a chain made of metallic nanoparticles as a resonant light sail, attached by one end point to a transparent object and propelling it by the use of electromagnetic radiation. Driving forces exerted on the chain are theoretically studied as a function of radiation's wavelength and chain's alignments with respect to the direction of radiation. Interestingly, there is a window in the frequency spectrum in which null-torque equilibrium configuration, with minimum geometric cross section, corresponds to a maximum in the driving force.

  7. All-optical 3D atomic loops generated with Bessel light fields

    International Nuclear Information System (INIS)

    Volke-Sepulveda, Karen; Jauregui, RocIo

    2009-01-01

    The propagation invariance of Bessel beams as well as their transversal structure is used to perform a comparative analysis of their effect on cold atoms for four different configurations and combinations thereof. We show that, even at temperatures for which the classical description of the atom's centre-of-mass motion is valid, the interchange of momentum, energy and orbital angular momentum between light and atoms yields efficient tools for all-optical trapping, transporting and, in general, manipulating the state of motion of cold atoms.

  8. Error sources in the real-time NLDAS incident surface solar radiation and an evaluation against field observations and the NARR

    Science.gov (United States)

    Park, G.; Gao, X.; Sorooshian, S.

    2005-12-01

    The atmospheric model is sensitive to the land surface interactions and its coupling with Land surface Models (LSMs) leads to a better ability to forecast weather under extreme climate conditions, such as droughts and floods (Atlas et al. 1993; Beljaars et al. 1996). However, it is still questionable how accurately the surface exchanges can be simulated using LSMs, since terrestrial properties and processes have high variability and heterogeneity. Examinations with long-term and multi-site surface observations including both remotely sensed and ground observations are highly needed to make an objective evaluation on the effectiveness and uncertainty of LSMs at different circumstances. Among several atmospheric forcing required for the offline simulation of LSMs, incident surface solar radiation is one of the most significant components, since it plays a major role in total incoming energy into the land surface. The North American Land Data Assimilation System (NLDAS) and North American Regional Reanalysis (NARR) are two important data sources providing high-resolution surface solar radiation data for the use of research communities. In this study, these data are evaluated against field observations (AmeriFlux) to identify their advantages, deficiencies and sources of errors. The NLDAS incident solar radiation shows a pretty good agreement in monthly mean prior to the summer of 2001, while it overestimates after the summer of 2001 and its bias is pretty close to the EDAS. Two main error sources are identified: 1) GOES solar radiation was not used in the NLDAS for several months in 2001 and 2003, and 2) GOES incident solar radiation when available, was positively biased in year 2002. The known snow detection problem is sometimes identified in the NLDAS, since it is inherited from GOES incident solar radiation. The NARR consistently overestimates incident surface solar radiation, which might produce erroneous outputs if used in the LSMs. Further attention is given to

  9. Neutrino transition magnetic moments and the solar magnetic field on the light of the Kamland evidence

    CERN Document Server

    Antonelli, V; Picariello, M; Pulido, J; Torrente-Lujan, E

    2003-01-01

    We present here a recopilation of recent results about the possibility of detecting solar electron antineutrinos produced by solar core and convective magnetic fields. These antineutrinos are predicted by spin-flavor oscillations at a significant rate even if this mechanism is not the leading solution to the SNP. Using the recent Kamland results and assuming a concrete model for antineutrino production by spin-flavor precession in the convective zone based on chaotic magnetic fields,we obtain bounds on the flux of solar antineutrinos, on the average conversion neutrino-antineutrino probability and on intrinsic neutrino magnetic moment. In the most conservative case, $\\mu\\lsim 2.5\\times 10^{-11} \\mu_B$ (95% CL). When studying the effects of a core magnetic field, we find in the weak limit a scaling of the antineutrino probability with respect to the magnetic field profile in the sense that the same probability function can be reproduced by any profile with a suitable peak field value. In this way the solar ele...

  10. Free-Free Transitions of the e-H System Inside a Dense Plasma Irradiated by a Laser Field at Very Low Incident-Electron Energies

    Science.gov (United States)

    Bhatia, A. K.; Sinha, C.

    2012-01-01

    The free-free transition is studied for an electron-hydrogen atom in ground state when a low-energy electron (external) is injected into hydrogenic plasma in the presence of an external homogenous, monochromatic, and linearly polarized laser field. The effect of plasma screening is considered in the Debye-Huckel approximation. The calculations are performed in the soft photon limit. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. The space part of the scattering wave function for the electron is solved numerically by taking into account the electron exchange. The laser-assisted differential and total cross sections are calculated for single-photon absorption or emission and no-photon exchange in the soft photon limit, the laser intensity being much less than the atomic field intensity. The calculations have been carried out for various values of Debye parameter, ranging from 0.005 to 0.12. A strong suppression is noted in the laser-assisted cross sections as compared to the field-free situation. A significant difference is noted for the singlet and triplet cross sections. The suppression is much more in the triplet states.

  11. Hidden in the light: Magnetically induced afterglow from trapped chameleon fields

    International Nuclear Information System (INIS)

    Gies, Holger; Mota, David F.; Shaw, Douglas J.

    2008-01-01

    We propose an afterglow phenomenon as a unique trace of chameleon fields in optical experiments. The vacuum interaction of a laser pulse with a magnetic field can lead to a production and subsequent trapping of chameleons in the vacuum chamber, owing to their mass dependence on the ambient matter density. Magnetically induced reconversion of the trapped chameleons into photons creates an afterglow over macroscopic timescales that can conveniently be searched for by current optical experiments. We show that the chameleon parameter range accessible to available laboratory technology is comparable to scales familiar from astrophysical stellar energy-loss arguments. We analyze quantitatively the afterglow properties for various experimental scenarios and discuss the role of potential background and systematic effects. We conclude that afterglow searches represent an ideal tool to aim at the production and detection of cosmologically relevant scalar fields in the laboratory

  12. Induced Light Emission from Quantum Dots: The Directional Near-Field Pattern

    DEFF Research Database (Denmark)

    Iezhokin, Igor; Keller, Ole; Lozovski, Valeri

    2010-01-01

    The optical Lippmann-Schwinger equation, supplemented by the microscopic conductivity tensor, is used to establish a near-field radiation theory for a mesoscopic particle. The present theory deviates from previous ones in that it allows one to take into account the finite size of the particle...... in a selfconsistent local-field calculation. The main result of the basic theory is illustrated by a number of numerical calculations on box-shaped quantum dots keeping only two optically mobile electrons. Particular attendance is paid to the distance and angular dependences of the near-field radiation pattern When...... the distance between the particle and observation point exceeds just a few times the linear dimension of the particle the directional radiation diagrams all become qualitatively identical to those of an electric point-dipole radiator The result of the present theory may be of particular interest for studies...

  13. Investigations into light-front interactions for massless fields (I): non-constructibility of higher spin quartic amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Bengtsson, Anders K.H. [Academy of Textiles, Engineering and Economics, University of Borås,Allégatan 1, SE-50190 Borås (Sweden)

    2016-12-27

    The dynamical commutators of the light-front Poincaré algebra yield first order differential equations in the p{sup +} momenta for the interaction vertex operators. The homogeneous solution to the equation for the quartic vertex is studied. Consequences as regards the constructibility assumption of quartic higher spin amplitudes from cubic amplitudes are discussed. The existence of quartic contact interactions unrelated to cubic interactions by Poincaré symmetry indicates that the higher spin S-matrix is not constructible. Thus quartic amplitude based no-go results derived by BCFW recursion for Minkowski higher spin massless fields may be circumvented.

  14. White-light full-field OCT resolution improvement by image sensor colour balance adjustment: numerical simulation

    International Nuclear Information System (INIS)

    Kalyanov, A L; Lychagov, V V; Ryabukho, V P; Smirnov, I V

    2012-01-01

    The possibility of improving white-light full-field optical coherence tomography (OCT) resolution by image sensor colour balance tuning is shown numerically. We calculated the full-width at half-maximum (FWHM) of a coherence pulse registered by a silicon colour image sensor under various colour balance settings. The calculations were made for both a halogen lamp and white LED sources. The results show that the interference pulse width can be reduced by the proper choice of colour balance coefficients. The reduction is up to 18%, as compared with a colour image sensor with regular settings, and up to 20%, as compared with a monochrome sensor. (paper)

  15. Nonreciprocal propagation of light without external magnetic fields in a semiconductor waveguide isolator with a MnAs layer

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, T. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan) and Japan Science and Techonology Agency, SORST (Japan)]. E-mail: ametomo@hotaka.t.u-tokyo.ac.jp; Shimizu, H. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Japan Science and Techonology Agency, SORST (Japan); Hai, P.N. [Department of Electronic Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Japan Science and Techonology Agency, SORST (Japan); Tanaka, M. [Department of Electronic Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Japan Science and Techonology Agency, SORST (Japan); Nakano, Y. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Japan Science and Techonology Agency, SORST (Japan)

    2007-03-15

    A 1.5-{mu}m, TM-mode waveguide optical isolator was developed for use in photonic integrated circuits. It consists of an InGaAlAs-based optical waveguide with a ferromagnetic MnAs layer and makes use of nonreciprocal propagation loss of light induced by the magnetized MnAs layer. With a large-remanence MnAs layer grown with the Mn-template epitaxy method, the isolator successfully showed an 8.7 dB/mm isolation ratio without external magnetic fields.

  16. Control of electric field in CdZnTe radiation detectors by above-bandgap light

    International Nuclear Information System (INIS)

    Franc, J.; Dědič, V.; Rejhon, M.; Zázvorka, J.; Praus, P.; Touš, J.; Sellin, P. J.

    2015-01-01

    We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states

  17. Control of electric field in CdZnTe radiation detectors by above-bandgap light

    Energy Technology Data Exchange (ETDEWEB)

    Franc, J.; Dědič, V.; Rejhon, M.; Zázvorka, J.; Praus, P. [Institute of Physics of Charles University, Prague (Czech Republic); Touš, J. [Crytur Ltd., Turnov (Czech Republic); Sellin, P. J. [Department of Physics, University of Surrey, Guildford (United Kingdom)

    2015-04-28

    We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states.

  18. Arctic Riverine CDOM and its effects on the Polar Marine Light Field

    Energy Technology Data Exchange (ETDEWEB)

    Orandle, Zoe Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weijer, Wilbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Elliott, Scott M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Shanlin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-28

    It is well-known that CDOM (Chromophoric Dissolved Organic Matter) can have a significant effect on biological activity in the photic zones of aquatic ecosystems. However, the extent of CDOM’s interference with biological activity is not well-known. We examined this issue in great detail in the mixed surface layer of the Arctic Ocean. We studied the impacts of CDOM’s light attenuation on Arctic phytoplankton populations to discover if riverine CDOM’s presence in the Arctic ocean could inhibit and possibly prevent local phytoplankton populations from performing photosynthesis. We incorporated biogeochemistry concepts and data with oceanographic models and calculations to approach the problem. The results showed that riverine CDOM can indeed significantly impact the productivity of phytoplankton populations during the spring and summer months near the major Arctic river mouths we chose to examine. Although our study was detailed and inclusive of many variables, the issue of CDOM’s light attenuation and its effects on phytoplankton populations must be explored on a global scale to help understand if riverine CDOM could prove disastrous for phytoplankton populations.

  19. Incidence, Mechanisms, and Severity of Match-Related Collegiate Men's Soccer Injuries on FieldTurf and Natural Grass Surfaces: A 6-Year Prospective Study.

    Science.gov (United States)

    Meyers, Michael C

    2017-03-01

    Numerous injuries have been attributed to playing on artificial turf. More recently, newer generations of artificial turf have been developed to duplicate the playing characteristics of natural grass. Although artificial turf has been deemed safer than natural grass in some studies, few long-term studies have been conducted comparing match-related collegiate soccer injuries between the 2 playing surfaces. Collegiate male soccer athletes do not experience any difference in the incidence, mechanisms, or severity of match-related injuries between FieldTurf and natural grass. Cohort study; Level of evidence, 2. Male soccer athletes from 11 universities were evaluated over 6 seasons. Demographic features and predictors included player position, cleat design, player weight, turf age, and environmental factors. Outcomes of interest included injury incidence, injury category, time loss, injury mechanism and situation, type of injury, injury grade and anatomic location, injury severity, head and lower extremity trauma, and elective medical procedures. All match-related injuries were evaluated by the attending head athletic trainer and team physicians on site and subsequently in the physician's office when further follow-up and treatment were deemed necessary. In sum, 765 collegiate games were evaluated for match-related soccer injuries sustained on FieldTurf or natural grass during 6 seasons. Overall, 380 team games (49.7%) were played on FieldTurf versus 385 team games (50.3%) played on natural grass. A total of 722 injuries were documented, with 268 (37.1%) occurring on FieldTurf and 454 (62.9%) on natural grass. Multivariate analysis per 10 team games indicated a significant playing surface effect: F 2,720 = 7.260, P = .001. A significantly lower total injury incidence rate (IIR) of 7.1 (95% CI, 6.6-7.5) versus 11.8 (95% CI, 11.3-12.2; P < .0001) and lower rate of substantial injuries, 0.7 (95% CI, 0.5-1.0) versus 1.9 (95% CI, 1.5-2.3; P < .03), were documented on Field

  20. High-efficiency and flexible generation of vector vortex optical fields by a reflective phase-only spatial light modulator.

    Science.gov (United States)

    Cai, Meng-Qiang; Wang, Zhou-Xiang; Liang, Juan; Wang, Yan-Kun; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2017-08-01

    The scheme for generating vector optical fields should have not only high efficiency but also flexibility for satisfying the requirements of various applications. However, in general, high efficiency and flexibility are not compatible. Here we present and experimentally demonstrate a solution to directly, flexibly, and efficiently generate vector vortex optical fields (VVOFs) with a reflective phase-only liquid crystal spatial light modulator (LC-SLM) based on optical birefringence of liquid crystal molecules. To generate the VVOFs, this approach needs in principle only a half-wave plate, an LC-SLM, and a quarter-wave plate. This approach has some advantages, including a simple experimental setup, good flexibility, and high efficiency, making the approach very promising in some applications when higher power is need. This approach has a generation efficiency of 44.0%, which is much higher than the 1.1% of the common path interferometric approach.

  1. High-field strong-focusing undulator designs for X-ray Linac Coherent Light Source (LCLS) applications

    International Nuclear Information System (INIS)

    Caspi, S.; Schlueter, R.; Tatchyn, R.

    1995-01-01

    Linac-driven X-Ray Free Electron Lasers (e.g., Linac Coherent Light Sources (LCLSs)), operating on the principle of single-pass saturation in the Self-Amplified Spontaneous Emission (SASE) regime typically require multi-GeV beam energies and undulator lengths in excess of tens of meters to attain sufficient gain in the 1 angstrom--0.1 angstrom range. In this parameter regime, the undulator structure must provide: (1) field amplitudes B 0 in excess of 1T within periods of 4cm or less, (2) peak on-axis focusing gradients on the order of 30T/m, and (3) field quality in the 0.1%--0.3% range. In this paper the authors report on designs under consideration for a 4.5--1.5 angstrom LCLS based on superconducting (SC), hybrid/PM, and pulsed-Cu technologies

  2. APPLICATION OF LIGHT EMITTING DIODE IRRADIATION IN SURGERY AND OTHER FIELDS OF MEDICINE

    Directory of Open Access Journals (Sweden)

    Iskander Mukhamedovich Baybekov

    2017-05-01

    Full Text Available Goal. To study the experience of using Light Emitting Diode (LED in surgery and other areas of medicine. Methods and methodology. The methodological basis is the analysis of literature, synthesis of the results of experimental and clinical studies, as well as a modern interpretation of the mechanisms of action of low-intensity laser radiation and LED effects on the body. Special attention is paid to the experience of clinical and morphological studies LED of impacts at the Republican specialized center of surgery named academician V. Vahidov of the Ministry of health of the Republic of Uzbekistan. Results. Comparative features of LED and lasers, such as stimulation of reparative processes, their influence on healing of skin wounds and sternum after sternotomy, red blood cells and microcirculation are discussed. Conclusion. It has been suggested that LED is a worthy alternative to lasers. Their use is advisable in complex treatment of surgical diseases.

  3. Detection of ultraviolet Cherenkov light from high energy cosmic ray atmospheric showers: A field test

    International Nuclear Information System (INIS)

    Bartoli, B.; Peruzzo, L.; Sartori, G.; Bedeschi, F.; Bertolucci, E.; Mariotti, M.; Menzione, A.; Ristori, L.; Stefanini, A.; Zetti, F.; Scribano, A.; Budinich, M.; Liello, F.

    1991-01-01

    We present the results of a test with a prototype apparatus aimed to detect the ultraviolet Cherenkov light in the wavelenght range 2000-2300A, emitted by high energy cosmic ray showers. The system consists of a gas proportional chamber, with TMAE vapour as the photosensitive element, placed on the focal plane of a 1.5 m diameter parabolic mirror. The test was done during the summer of 1989 with cosmic ray showers seen in coincidence with the EAS-TOP experiment, an extended atmospheric shower charged particle array now being exploited at Campo Imperatore, 1900 m above sea level, on top of the Gran Sasso underground Laboratory of INFN. The results were positive and show that a full scale ultraviolet Cherenkov experiment with good sensitivity, angular resolution and virtually no background from moonlight or even daylight can be envisaged. (orig.)

  4. Means to improve light source productivity: from proof of concept to field implementation

    Science.gov (United States)

    Rausa, E.; Cacouris, T.; Conley, W.; Jackson, M.; Luo, S.; Murthy, S.; Rechtsteiner, G.; Steiner, K.

    2016-03-01

    Light source technological performance is key to enabling chipmaker yield and production success. Just as important is ensuring that performance is consistent over time to help maintain as high an uptime as possible on litho-cells (scanner and track combination). While it is common to see average tool uptime of over 99% based on service intervention time, we will show that there are opportunities to improve equipment availability through a multifaceted approach that can deliver favorable results and significantly improve on the actual production efficiency of equipment. The majority of chipmakers are putting light source data generated by tools such as Cymer OnLine (COL), OnPulse Plus, and SmartPulse to good use. These data sets, combined with in-depth knowledge of the equipment, makes it possible to draw powerful conclusions that help increase both chip manufacturing consistency as well as equipment productivity. This discussion will focus on the latter, equipment availability, and how data analysis can help increase equipment availability for Cymer customers. There are several types of opportunities for increasing equipment availability, but in general we can focus on two primary categories: 1) scheduled downtime and 2) unscheduled downtime. For equipment that is under control of a larger entity, as the laser is to the scanner, there are additional categories related to either communication errors or better synchronization of events that can maximize overall litho-cell efficiency. In this article we will focus on general availability without highlighting the specific cause of litho-cell (laser, scanner and track). The goal is to increase equipment available time with a primary focus is on opportunities to minimize errors and variabilities.

  5. Comparison of Light Interception and Field Photosynthesis between Vertically and Horizontally Trained Watermelon [Citrullus lanatus (Thunb.) Matsum. et Nakai] Plants

    International Nuclear Information System (INIS)

    Watanabe, S.; Nakano, Y.; Okano, K.

    2001-01-01

    The light-interception characteristics and field photosynthetic rates of individual leaves were compared between vertically and horizontally trained watermelon plants to determine why the former produced smaller fruit than the latter. The planting density of the vertically trained plants was 3 times greater than that of the horizontally trained plants, because in the former the shoots were trained upward, whereas the latter were spread on the ground. Although the amount of solar radiation received by the upper leaves was similar in both plots, significantly less light was received by the middle and lower leaves of the vertically trained plants than by those of the horizontally trained ones. In the vertically trained plants, the photosynthetic rate was high at the upper leaves and decreased gradually with lower leaf positions. The photosynthetic rate in the horizontally trained plants was generally high, but the difference in the rate among leaves in different positions varied. We conclude that the main reason for the lighter fruits on the vertically trained watermelon plants is that the middle and lower leaves received less light because of shading compared with horizontally grown vines

  6. Light extinction method for diagnostics of particles sizes formed in magnetic field

    Science.gov (United States)

    Myshkin, Vyacheslav; Izhoykin, Dmitry; Grigoriev, Alexander; Gamov, Denis; Leonteva, Daria

    2018-03-01

    The results of laser diagnostics of dispersed particles formed upon cooling of Zn vapor are presented. The radiation attenuation in the wavelength range 420-630 nm with a step of 0.3 nm was registered. The attenuation coefficients spectral dependence was processed using known algorithms for integral equation solving. The 10 groups of 8 attenuation coefficients were formed. Each group was processed taking with considering of previous decisions. After processing of the 10th group of data, calculations were repeated from the first one. Data of the particles sizes formed in a magnetic field of 0, 44 and 76 mT are given. A model of physical processes in a magnetic field is discussed.

  7. Incidence and Identification of Root-Knot Nematode in Plastic-House Fields of Central Area of Korea

    Directory of Open Access Journals (Sweden)

    Hyoung Rai Ko

    2017-12-01

    Full Text Available To investigate occurrence of root-knot nematode (RKN in plastic house of central area of Korea, 132 soil samples were collected in cucumber, water melon, tomato, red pepper and strawberry fields from 2013 to 2015. Among 132 soil samples, 65 soil samples (49% were infested with RKN and mean density of RKN was 178 second-stage juveniles per 100 cm³ soil (min. 1 ~ max. 3,947. The frequency of RKN by regional was the highest in Chuncheon with 80%, followed by Cheonan (68%, Nonsan (36%, Buyeo (33% and Yesan (30%. The frequency of RKN by crops was the highest in tomato with 83%, followed by cucumber (61%, strawberry (41%, red pepper (30%, watermelon (26%. To identify the species of RKN, fifteen populations were selected for representative populations. As a phylogenetic analysis of 15 populations, southern root-knot nematode (Meloidogyne incognita, peanut root-knot nematode (M. arenaria and northern root-knot nematode (M. hapla were identified with 47%, 20% and 33% ratio, respectively. In crops, M. incognita, M. arenaria and M. hapla were detected in tomato, M. incognita and M. arenaria were detected in cucumber and watermelon, and M. hapla was detected in strawberry and lettuce. Thus, there should be a continuous management to major species of each crops to prevent dispersal of RKN damages.

  8. DEM RECONSTRUCTION USING LIGHT FIELD AND BIDIRECTIONAL REFLECTANCE FUNCTION FROM MULTI-VIEW HIGH RESOLUTION SPATIAL IMAGES

    Directory of Open Access Journals (Sweden)

    F. de Vieilleville

    2016-06-01

    Full Text Available This paper presents a method for dense DSM reconstruction from high resolution, mono sensor, passive imagery, spatial panchromatic image sequence. The interest of our approach is four-fold. Firstly, we extend the core of light field approaches using an explicit BRDF model from the Image Synthesis community which is more realistic than the Lambertian model. The chosen model is the Cook-Torrance BRDF which enables us to model rough surfaces with specular effects using specific material parameters. Secondly, we extend light field approaches for non-pinhole sensors and non-rectilinear motion by using a proper geometric transformation on the image sequence. Thirdly, we produce a 3D volume cost embodying all the tested possible heights and filter it using simple methods such as Volume Cost Filtering or variational optimal methods. We have tested our method on a Pleiades image sequence on various locations with dense urban buildings and report encouraging results with respect to classic multi-label methods such as MIC-MAC, or more recent pipelines such as S2P. Last but not least, our method also produces maps of material parameters on the estimated points, allowing us to simplify building classification or road extraction.

  9. A study of effects of electrode contacts on performance of organic-based light-emitting field-effect transistors

    Science.gov (United States)

    Kim, Dae-Kyu; Choi, Jong-Ho

    2018-02-01

    Herein is presented a comparative performance analysis of heterojunction organic-based light-emitting field-effect transistors (OLEFETs) with symmetric (Au only) and asymmetric (Au and LiF/Al) electrode contacts. The devices had a top source-drain contact with long-channel geometry and were produced by sequentially depositing p-type pentacene and n-type N,N‧-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (P13) using a neutral cluster beam deposition apparatus. The spectroscopic, structural and morphological properties of the organic thin films were examined using photoluminescence (PL) spectroscopy, X-ray diffraction (XRD) method, laser scanning confocal and atomic force microscopy (LSCM, AFM). Based upon the growth of high-quality, well-packed crystalline thin films, the devices demonstrated ambipolar field-effect characteristics, stress-free operational stability, and light emission under ambient conditions. Various device parameters were derived from the fits of the observed characteristics. The hole mobilities were nearly equal irrespective of the electrode contacts, whereas the electron mobilities of the transistors with LiF/Al drain electrodes were higher due to the low injection barrier. For the OLEFETs with symmetric electrodes, electroluminescence (EL) occurred only in the vicinity of the hole-injecting electrode, whereas for the OLEFETs with asymmetric electrodes, the emission occurred in the vicinity of both hole- and electron-injecting electrodes. By tuning the carrier injection and transport through high- and low-work function metals, the hole-electron recombination sites could be controlled. The operating conduction and light emission mechanism are discussed with the aid of EL images obtained using a charge-coupled device (CCD) camera.

  10. Influence of light waves on the thermoelectric power under large magnetic field in III-V, ternary and quaternary materials

    Energy Technology Data Exchange (ETDEWEB)

    Ghatak, K.P. [Department of Electronic Science, The University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Bhattacharya, S. [Post Graduate Department of Computer Science, St. Xavier' s College, 30 Park Street, Kolkata 700 016 (India); Pahari, S. [Department of Administration, Jadavpur University, Kolkata 700 032 (India); De, D. [Department of Computer Science and Engineering, West Bengal University of Technology, B. F. 142, Sector I, Salt Lake, Kolkata 700 064 (India); Ghosh, S.; Mitra, M. [Department of Electronics and Telecommunication Engineering, Bengal Engineering and Science University, Howrah 711 103 (India)

    2008-04-15

    We study theoretically the influence of light waves on the thermoelectric power under large magnetic field (TPM) for III-V, ternary and quaternary materials, whose unperturbed energy-band structures, are defined by the three-band model of Kane. The solution of the Boltzmann transport equation on the basis of this newly formulated electron dispersion law will introduce new physical ideas and experimental findings in the presence of external photoexcitation. It has been found by taking n-InAs, n-InSb, n-Hg{sub 1-x}Cd{sub x}Te and n-In{sub 1-x}Ga{sub x}As{sub y}P{sub 1-y} lattice matched to InP as examples that the TPM decreases with increase in electron concentration, and increases with increase in intensity and wavelength, respectively in various manners. The strong dependence of the TPM on both light intensity and wavelength reflects the direct signature of light waves that is in direct contrast as compared with the corresponding bulk specimens of the said materials in the absence of external photoexcitation. The rate of change is totally band-structure dependent and is significantly influenced by the presence of the different energy-band constants. The well-known result for the TPM for nondegenerate wide-gap materials in the absence of light waves has been obtained as a special case of the present analysis under certain limiting conditions and this compatibility is the indirect test of our generalized formalism. Besides, we have also suggested the experimental methods of determining the Einstein relation for the diffusivity:mobility ratio, the Debye screening length and the electronic contribution to the elastic constants for materials having arbitrary dispersion laws. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  11. Biophysical controls on light response of net CO2 exchange in a winter wheat field in the North China Plain.

    Directory of Open Access Journals (Sweden)

    Xiaojuan Tong

    Full Text Available To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE, CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (P max was 46.6 ± 4.0 µmol CO2 m(-2 s(-1 and initial light use efficiency (α 0.059 ± 0.006 µmol µmol(-1 in April-May, two or three times as high as those in March. Stepwise multiple linear regressions showed that P max increased with the increase in leaf area index (LAI, canopy conductance (g c and air temperature (T a but declined with increasing vapor pressure deficit (VPD (P25°C or VPD>1.1-1.3 kPa, NEE residual increased with the increase in T a and VPD (P<0.001, indicating that temperature and water stress occurred. When g c was more than 14 mm s(-1 in March and May and 26 mm s(-1 in April, the NEE residuals decline disappeared, or even turned into an increase in g c (P<0.01, implying shifts from stomatal limitation to non-stomatal limitation on NEE. Although the differences between sunny and cloudy sky conditions were unremarkable for light response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003-2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales.

  12. Electric dipole moments of light nuclei in chiral effective field theory

    International Nuclear Information System (INIS)

    Bsaisou, Jan

    2014-01-01

    Analysis (NDA) estimates of the coupling constants. These estimates prove to be sufficient to reveal certain hierarchies of coupling constants. The different hierarchies of coupling constants translate into different hierarchies of the nuclear contributions to the EDMs of light nuclei. We calculate within the framework of ChPT the two-nucleon contributions to the EDM of the deuteron up to and including next-to-next-to leading order and the two-nucleon contributions to the EDMs of the helion ( 3 He nucleus) and the triton ( 3 H nucleus) up to and including next-to-leading order. These computations comprise thorough investigations of the uncertainties of the results from the P- and T-violating component as well as the P- and T-conserving component of the nuclear potential. We present quantitative predictions of the nuclear contributions to the EDMs of the deuteron, the helion and the triton induced by the QCD θ-term as functions of anti θ with well-defined uncertainties. The EDM predictions for the effective dimension-six sources are given as function of the yet unknown LECs with NDA estimates. We present several strategies to falsify the QCD θ-term as a relevant source of P and T violation by a suitable combination of measurements of several light nuclei and, if needed, supplementary lattice QCD input. If the QCD θ-term fails these tests, one or several of the effective dimension-six sources encoding physics beyond the Standard Model are most likely the source(s) of P and T violation. We demonstrate how particular effective dimension-six sources can be tested by EDM measurements of light nuclei with eventually supplementary Lattice QCD input.

  13. Electric dipole moments of light nuclei in chiral effective field theory

    Energy Technology Data Exchange (ETDEWEB)

    Bsaisou, Jan

    2014-04-25

    Dimensional Analysis (NDA) estimates of the coupling constants. These estimates prove to be sufficient to reveal certain hierarchies of coupling constants. The different hierarchies of coupling constants translate into different hierarchies of the nuclear contributions to the EDMs of light nuclei. We calculate within the framework of ChPT the two-nucleon contributions to the EDM of the deuteron up to and including next-to-next-to leading order and the two-nucleon contributions to the EDMs of the helion ({sup 3}He nucleus) and the triton ({sup 3}H nucleus) up to and including next-to-leading order. These computations comprise thorough investigations of the uncertainties of the results from the P- and T-violating component as well as the P- and T-conserving component of the nuclear potential. We present quantitative predictions of the nuclear contributions to the EDMs of the deuteron, the helion and the triton induced by the QCD θ-term as functions of anti θ with well-defined uncertainties. The EDM predictions for the effective dimension-six sources are given as function of the yet unknown LECs with NDA estimates. We present several strategies to falsify the QCD θ-term as a relevant source of P and T violation by a suitable combination of measurements of several light nuclei and, if needed, supplementary lattice QCD input. If the QCD θ-term fails these tests, one or several of the effective dimension-six sources encoding physics beyond the Standard Model are most likely the source(s) of P and T violation. We demonstrate how particular effective dimension-six sources can be tested by EDM measurements of light nuclei with eventually supplementary Lattice QCD input.

  14. Effect of farmyard manure after methane fermentation in the light of field experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kuzelewski, L; Pentkowski, A

    1961-01-01

    Yard manure after CH/sub 4/ fermentation was compared with manure kept in a manure pit with respect to composition and the effect on the crop, in both pot and field experiments. CH/sub 4/ fermentation reduced N losses of fresh manure and made for more easily assimilable N compounds. However, the first year and after-effects on crops of both types of manure were the same. No differences were noted for fermented manure due to ploughing over as compared to mere spreading on the soil.

  15. Derivation of sum rules for quark and baryon fields. [light-like charges

    Energy Technology Data Exchange (ETDEWEB)

    Bongardt, K [Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Theoretische Kernphysik

    1978-08-21

    In an analogous way to the Weinberg sum rules, two spectral-function sum rules for quark and baryon fields are derived by means of the concept of lightlike charges. The baryon sum rules are valid for the case of SU/sub 3/ as well as for SU/sub 4/ and the one-particle approximation yields a linear mass relation. This relation is not in disagreement with the normal linear GMO formula for the baryons. The calculated masses of the first resonance states agree very well with the experimental data.

  16. Superposition of number and squeezed states of the quantized light field

    International Nuclear Information System (INIS)

    De Brito, A.L.; Marques, G.A.; Baseia, B.; Dias, H.

    1998-01-01

    A recent paper in the literature (Mod. Phys. Lett. B, 9 (1995) 1673) introduced the Intermediate Number Squeezed State (INSS) of the quantized radiation field interpolating between the number state (n) and the squeezed-coherent state (z, α), exhibiting various nonclassical properties. Here, it's introduced an alternative state, interpolating between those limiting states and show that nonclassical effects in this new intermediate state can be greater than those exhibited by the INSS, depending on the values of the interpolating parameters. Although constituting an application of a general approach (Nuovo Cimento D, 18 (1996) 425), it concludes another case in the literature (Phys. Scr., 55 (1997) 179) as a particularisation of this

  17. 3D study in modelling in static regime of a bi facial polycrystalline solar cell under intense light and under a constant magnetic field

    International Nuclear Information System (INIS)

    ZOUNGRANA Martial

    2010-01-01

    In this work we propose a three-dimensional (3D) study of magnetic field, light concentration and electron gradient concentration electric field respective influences on bi facial polycrystalline silicon solar cell behaviour. The hold account of these parameters in our study leads to the new expressions of continuity equations, electric and electronic parameters. On the basis of these equations, grain size, grain boundary recombination velocity, magnetic field and light intensity effects on carriers density, photocurrent, photovoltage, electric and electronic parameters are analysed. We finally propose an equivalent electric model of bi facial polycrystalline silicon solar cell under magnetic field. According to this model, electric parameters expressions was established (shunt and series resistances, space charge zone capacity ) and we study magnetic field, grain size, grain boundary recombination velocity and light concentration influences on these parameters.(Author) [fr

  18. The effect of blue-enriched white light on cognitive performances and sleepiness of night-shift workers: A field study.

    Science.gov (United States)

    Motamedzadeh, Majid; Golmohammadi, Rostam; Kazemi, Reza; Heidarimoghadam, Rashid

    2017-08-01

    Night-shift works are basically accompanied by reduced cognitive performance, sleepiness, and higher possibility for human error and related incidents. It is therefore crucial to improve individuals' performance and alertness in sensitive places like industries' control room with the ultimate goal of increasing efficiency and reducing the number of possible incidents. Previous research has indicated that blue light is a critical cue for entraining circadian rhythm. As a result, the present study was an attempt to investigate whether blue-enriched white light illumination was a practical strategy to decrease sleepiness and improve cognitive performance during night shifts. The study, which adopted a before-after interventional design, was conducted among 30 control room staff members of petrochemical industry. After baseline assessments under existing lighting conditions, every participant was exposed to two new lighting conditions (namely, 17,000K and 6500K blue-enriched white light), each lasting for a week. Assessments were conducted again at the end of these treatments. In order to measure the subjective sleepiness, Karolinska Sleepiness Scale (KSS) was utilized. Subjects also performed the Conners' Continuous Performance Test II (CPT-II) and 1-back test in order to gauge their cognitive performance, and melatonin assessment was carried out using salivary and Eliza technique. The data was analyzed using two-way repeated measure ANOVA. The results indicated that, compared to normal lighting conditions, participants' sleepiness and melatonin rhythm significantly declined when they were exposed to blue-enriched white light. Furthermore, the experimental condition had a significant effect on the reduction of working memory errors. It also decreased omission errors and the reaction time during the sustained attention task. Thus, using blue-enriched white light may be a proper ergonomic strategy for improving performance and alertness, especially during night, in

  19. Crystal field effect in light actinide dioxides and oxychalcogenides - a unified phenomenological description

    Energy Technology Data Exchange (ETDEWEB)

    Gajek, Z. E-mail: gajek@int.pan.wroc.pl

    2004-05-01

    The electronic properties of the actinide ions in the series of semi-conducting, antiferromagnetic compounds: dioxides, AnO{sub 2} and oxychalcogenides, AnOY, where An=U, Np and Y=S, Se, are re-examined from the point of view of the consistency of the crystal field (CF) model. The discussion is based on the supposition that the effective metal-ligand interaction solely determines the net CF effect in non-metallic compounds. The main question we address here is, whether a reliable, consistent description of the CF effect in terms of the intrinsic parameters can be achieved for this particular family of compounds. Encouraging calculations reported previously for the AnO{sub 2} and UOY series serve as a reference data in the present estimation of electronic structure parameters for neptunium oxychalcogenides.

  20. Crystal field effect in light actinide dioxides and oxychalcogenides-a unified phenomenological description

    Science.gov (United States)

    Gajek, Z.

    2004-05-01

    The electronic properties of the actinide ions in the series of semi-conducting, antiferromagnetic compounds: dioxides, AnO2 and oxychalcogenides, AnOY, where An=U, Np and Y=S, Se, are re-examined from the point of view of the consistency of the crystal field (CF) model. The discussion is based on the supposition that the effective metal-ligand interaction solely determines the net CF effect in non-metallic compounds. The main question we address here is, whether a reliable, consistent description of the CF effect in terms of the intrinsic parameters can be achieved for this particular family of compounds. Encouraging calculations reported previously for the AnO2 and UOY series serve as a reference data in the present estimation of electronic structure parameters for neptunium oxychalcogenides.

  1. Crystal field effect in light actinide dioxides and oxychalcogenides - a unified phenomenological description

    International Nuclear Information System (INIS)

    Gajek, Z.

    2004-01-01

    The electronic properties of the actinide ions in the series of semi-conducting, antiferromagnetic compounds: dioxides, AnO 2 and oxychalcogenides, AnOY, where An=U, Np and Y=S, Se, are re-examined from the point of view of the consistency of the crystal field (CF) model. The discussion is based on the supposition that the effective metal-ligand interaction solely determines the net CF effect in non-metallic compounds. The main question we address here is, whether a reliable, consistent description of the CF effect in terms of the intrinsic parameters can be achieved for this particular family of compounds. Encouraging calculations reported previously for the AnO 2 and UOY series serve as a reference data in the present estimation of electronic structure parameters for neptunium oxychalcogenides

  2. Surgical lighting

    NARCIS (Netherlands)

    Knulst, A.J.

    2017-01-01

    The surgical light is an important tool for surgeons to create and maintain good visibility on the surgical task. Chapter 1 gives background to the field of (surgical) lighting and related terminology. Although the surgical light has been developed strongly since its introduction a long time ago,

  3. Comparison and correction of the light sensor output from 48 wearable light exposure devices by using a side-by-side field calibration method

    DEFF Research Database (Denmark)

    Markvart, Jakob; Hansen, Åse Marie; Christoffersen, Jens

    2015-01-01

    Measurement of personal light exposures and activity has gained popularity in studies of the circadian rhythm and its effects on human health. Calibration of a batch of measuring devices may be needed, especially before initiating interventional studies, but manufactory calibration of devices...... illuminance only to a minor degree and light source-specific calibration may therefore be needed in some cases. Moreover, light responses were found to vary between devices by up to 60%. Implications are that the results of light effects on health issues in studies using Actiwatches are blurred...

  4. A review on organic spintronic materials and devices: I. Magnetic field effect on organic light emitting diodes

    Directory of Open Access Journals (Sweden)

    Rugang Geng

    2016-06-01

    Full Text Available Organic spintronics is an emerging and potential platform for future electronics and display due to the intriguing properties of organic semiconductors (OSCs. For the past decade, studies have focused on three types of organic spintronic phenomena: (i magnetic field effect (MFE in organic light emitting diodes (OLEDs, where spin mixing between singlet and triplet polaron pairs (PP can be influenced by an external magnetic field leading to organic magnetoresistive effect (OMAR; (ii magnetoresistance (MR in organic spin valves (OSVs, where spin injection, transport, manipulation, and detection have been demonstrated; and (iii magnetoelectroluminescence (MEL bipolar OSVs or spin-OLEDs, where spin polarized electrons and holes are simultaneously injected into the OSC layer, leading to the dependence of electroluminescence intensity on relative magnetization of the electrodes. In this first of two review papers, we present major experimental results on OMAR studies and current understanding of OMAR using several spin dependent processes in organic semiconductors. During the discussion, we highlight some of the outstanding challenges in this promising research field. Finally, we provide an outlook on the future of organic spintronics.

  5. Probing different regimes of strong field light-matter interaction with semiconductor quantum dots and few cavity photons

    Science.gov (United States)

    Hargart, F.; Roy-Choudhury, K.; John, T.; Portalupi, S. L.; Schneider, C.; Höfling, S.; Kamp, M.; Hughes, S.; Michler, P.

    2016-12-01

    In this work we present an extensive experimental and theoretical investigation of different regimes of strong field light-matter interaction for cavity-driven quantum dot (QD) cavity systems. The electric field enhancement inside a high-Q micropillar cavity facilitates exceptionally strong interaction with few cavity photons, enabling the simultaneous investigation for a wide range of QD-laser detuning. In case of a resonant drive, the formation of dressed states and a Mollow triplet sideband splitting of up to 45 μeV is measured for a mean cavity photon number ≤slant 1. In the asymptotic limit of the linear AC Stark effect we systematically investigate the power and detuning dependence of more than 400 QDs. Some QD-cavity systems exhibit an unexpected anomalous Stark shift, which can be explained by an extended dressed 4-level QD model. We provide a detailed analysis of the QD-cavity systems properties enabling this novel effect. The experimental results are successfully reproduced using a polaron master equation approach for the QD-cavity system, which includes the driving laser field, exciton-cavity and exciton-phonon interactions.

  6. Cognition, Information Fields and Hologenomic Entanglement: Evolution in Light and Shadow

    Directory of Open Access Journals (Sweden)

    William B. Miller

    2016-05-01

    Full Text Available As the prime unification of Darwinism and genetics, the Modern Synthesis continues to epitomize mainstay evolutionary theory. Many decades after its formulation, its anchor assumptions remain fixed: conflict between macro organic organisms and selection at that level represent the near totality of any evolutionary narrative. However, intervening research has revealed a less easily appraised cellular and microbial focus for eukaryotic existence. It is now established that all multicellular eukaryotic organisms are holobionts representing complex collaborations between the co-aligned microbiome of each eukaryote and its innate cells into extensive mixed cellular ecologies. Each of these ecological constituents has demonstrated faculties consistent with basal cognition. Consequently, an alternative hologenomic entanglement model is proposed with cognition at its center and conceptualized as Pervasive Information Fields within a quantum framework. Evolutionary development can then be reconsidered as being continuously based upon communication between self-referential constituencies reiterated at every scope and scale. Immunological reactions support and reinforce self-recognition juxtaposed against external environmental stresses.

  7. Precise prediction for the light MSSM Higgs-boson mass combining effective field theory and fixed-order calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, Henning; Hollik, Wolfgang [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Munich (Germany)

    2016-09-15

    In the Minimal Supersymmetric Standard Model heavy superparticles introduce large logarithms in the calculation of the lightest CP-even Higgs-boson mass. These logarithmic contributions can be resummed using effective field theory techniques. For light superparticles, however, fixed-order calculations are expected to be more accurate. To gain a precise prediction also for intermediate mass scales, the two approaches have to be combined. Here, we report on an improvement of this method in various steps: the inclusion of electroweak contributions, of separate electroweakino and gluino thresholds, as well as resummation at the NNLL level. These improvements can lead to significant numerical effects. In most cases, the lightest CP-even Higgs-boson mass is shifted downwards by about 1 GeV. This is mainly caused by higher-order corrections to the MS top-quark mass. We also describe the implementation of the new contributions in the code FeynHiggs. (orig.)

  8. Monitoring the Erosion of Hydrolytically-Degradable Nanogels via Multiangle Light Scattering Coupled to Asymmetrical Flow Field-Flow Fractionation

    Science.gov (United States)

    Smith, Michael H.; South, Antoinette B.; Gaulding, Jeffrey C.; Lyon, L. Andrew

    2009-01-01

    We describe the synthesis and characterization of degradable nanogels that display bulk erosion under physiologic conditions (pH = 7.4, 37 °C). Erodible poly(N-isopropylmethacrylamide) nanogels were synthesized by copolymerization with N,O-(dimethacryloyl)hydroxylamine, a cross-linker previously used in the preparation of non-toxic and biodegradable bulk hydrogels. To monitor particle degradation, we employed multiangle light scattering and differential refractometry detection following asymmetrical flow field-flow fractionation. This approach allowed the detection of changes in nanogel molar mass and topology as a function of both temperature and pH. Particle erosion was evident from both an increase in nanogel swelling and a decrease in scattering intensity as a function of time. Following these analyses, the samples were recovered for subsequent characterization by direct particle tracking, which yields hydrodynamic size measurements and enables number density determination. Additionally, we confirmed the conservation of nanogel stimuli-responsivity through turbidity measurements. Thus, we have demonstrated the synthesis of degradable nanogels that erode under conditions and on timescales that are relevant for many drug delivery applications. The combined separation and light scattering detection method is demonstrated to be a versatile means to monitor erosion and should also find applicability in the characterization of other degradable particle constructs. PMID:20000662

  9. Magnetic field enhanced electroluminescence in organic light emitting diodes based on electron donor-acceptor exciplex blends

    Science.gov (United States)

    Baniya, Sangita; Basel, Tek; Sun, Dali; McLaughlin, Ryan; Vardeny, Zeev Valy

    2016-03-01

    A useful process for light harvesting from injected electron-hole pairs in organic light emitting diodes (OLED) is the transfer from triplet excitons (T) to singlet excitons (S) via reverse intersystem crossing (RISC). This process adds a delayed electro-luminescence (EL) emission component that is known as thermally activated delayed fluorescence (TADF). We have studied electron donor (D)/acceptor(A) blends that form an exciplex manifold in which the energy difference, ΔEST between the lowest singlet (S1) and triplet (T1) levels is relatively small (exciplex blend is enhanced up to 40% by applying a relatively weak magnetic field of 50 mT at ambient. Moreover the MEL response is activated with activation energy similar that of the EL emission. This suggests that the large magneto-EL originates from an additional spin-mixing channel between singlet and triplet states of the generated exciplexes, which is due to TADF. We will report on the MEL dependencies on the temperature, bias voltage, and D-A materials for optimum OLED performance. Supported by SAMSUNG Global Research Outreach (GRO) program, and also by the NSF-Material Science & Engineering Center (MRSEC) program at the University of Utah (DMR-1121252).

  10. Application of support vector regression for optimization of vibration flow field of high-density polyethylene melts characterized by small angle light scattering

    Science.gov (United States)

    Xian, Guangming

    2018-03-01

    In this paper, the vibration flow field parameters of polymer melts in a visual slit die are optimized by using intelligent algorithm. Experimental small angle light scattering (SALS) patterns are shown to characterize the processing process. In order to capture the scattered light, a polarizer and an analyzer are placed before and after the polymer melts. The results reported in this study are obtained using high-density polyethylene (HDPE) with rotation speed at 28 rpm. In addition, support vector regression (SVR) analytical method is introduced for optimization the parameters of vibration flow field. This work establishes the general applicability of SVR for predicting the optimal parameters of vibration flow field.

  11. Cavity Attenuated Phase Shift (CAPS) Method for Airborne Aerosol Light Extinction Measurement: Instrument Validation and First Results from Field Deployment

    Science.gov (United States)

    Petzold, A.; Perim de Faria, J.; Berg, M.; Bundke, U.; Freedman, A.

    2015-12-01

    Monitoring the direct impact of aerosol particles on climate requires the continuous measurement of aerosol optical parameters like the aerosol extinction coefficient on a regular basis. Remote sensing and ground-based networks are well in place (e.g., AERONET, ACTRIS), whereas the regular in situ measurement of vertical profiles of atmospheric aerosol optical properties remains still an important challenge in quantifying climate change. The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System; www.iagos.org) responds to the increasing requests for long-term, routine in situ observational data by using commercial passenger aircraft as measurement platform. However, scientific instrumentation for the measurement of atmospheric constituents requires major modifications before being deployable aboard in-service passenger aircraft. Recently, a compact and robust family of optical instruments based on the cavity attenuated phase shift (CAPS) technique has become available for measuring aerosol light extinction. While this technique was successfully deployed for ground-based atmospheric measurements under various conditions, its suitability for operation aboard aircraft in the free and upper free troposphere still has to be demonstrated. In this work, the modifications of a CAPS PMex instrument for measuring aerosol light extinction on aircraft, the results from subsequent laboratory tests for evaluating the modified instrument prototype, and first results from a field deployment aboard a research aircraft will be covered. In laboratory studies, the instrument showed excellent agreement (deviation CAPS PMex instrument response within 10% deviation. During the field deployment, aerosol extinction coefficients and associated aerosol size distributions have been measured and will be presented as comparison studies between measured and calculated data.

  12. Wheelchair incidents

    NARCIS (Netherlands)

    Drongelen AW van; Roszek B; Hilbers-Modderman ESM; Kallewaard M; Wassenaar C; LGM

    2002-01-01

    This RIVM study was performed to gain insight into wheelchair-related incidents with powered and manual wheelchairs reported to the USA FDA, the British MDA and the Dutch Center for Quality and Usability Research of Technical Aids (KBOH). The data in the databases do not indicate that incidents with

  13. Direct monitoring of erythrocytes aggregation under the effect of the low-intensity magnetic field by measuring light transmission at wavelength 800 nm

    Science.gov (United States)

    Elblbesy, Mohamed A.

    2017-12-01

    Interacting electromagnetic field with the living organisms and cells became of the great interest in the last decade. Erythrocytes are the most common types of the blood cells and have unique rheological, electrical, and magnetic properties. Aggregation is one of the important characteristics of the erythrocytes which has a great impact in some clinical cases. The present study introduces a simple method to monitor the effect of static magnetic field on erythrocytes aggregation using light transmission. Features were extracted from the time course curve of the light transmission through the whole blood under different intensities of the magnetic field. The findings of this research showed that static magnetic field could influence the size and the rate of erythrocytes aggregation. The strong correlations confirmed these results between the static magnetic field intensity and both the time of aggregation and sedimentation of erythrocytes. From this study, it can be concluded that static magnetic field can be used to modify the mechanisms of erythrocytes aggregation.

  14. Control of ascorbic acid synthesis and accumulation and glutathione by the incident light red/far red ratio in Phaseolus vulgaris leaves.

    Science.gov (United States)

    Bartoli, Carlos G; Tambussi, Eduardo A; Diego, Fanello; Foyer, Christine H

    2009-01-05

    The effects of red/far red (R/FR) ratios on leaf ascorbate (AA) and glutathione (GSH) accumulation were examined in common bean (Phaseolus vulgaris L.). Growth under low R/FR ratios resulted in a "shade" phenotype and much lower leaf AA and GSH contents than high (R/FR) ratios. Photosynthesis rates were unaffected by changes in the R/FR ratio but leaf respiration rates, pyridine nucleotide pools and antioxidant enzyme activities were decreased under the low R/FR regime. The GSH pool changed slowly in response to altered R/FR ratios but leaf ascorbate acclimated over a single photoperiod. We conclude that light quality signals, particularly R/FR ratios, are important regulators of antioxidant synthesis and accumulation. These acclimatory changes are an early response to changing light environment.

  15. Preparation of Ag deposited TiO2 (Ag/TiO2) composites and investigation on visible-light photocatalytic degradation activity in magnetic field

    Science.gov (United States)

    Zhang, L.; Ma, C. H.; Wang, J.; Li, S. G.; Li, Y.

    2014-12-01

    In this study, Ag deposited TiO2 (Ag/TiO2) composites were prepared by three different methods (Ultraviolet Irradiation Deposition (UID), Vitamin C Reduction (VCR) and Sodium Borohydride Reduction (SBR)) for the visible-light photocatalytic degradation of organic dyes in magnetic field. And then the prepared Ag deposited TiO2 (Ag/TiO2) composites were characterized physically by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The visible-light photocatalytic activities of these three kinds of Ag deposited TiO2 (Ag/TiO2) composites were examined and compared through the degradation of several organic dyes under visible-light irradiation in magnetic field. In addition, some influence factors such as visible-light irradiation time, organic dye concentration, revolution speed, magnetic field intensity and organic dye kind on the visible-light photocatalytic activity of Ag deposited TiO2 (Ag/TiO2) composite were reviewed. The research results showed that the presence of magnetic field significantly enhanced the visible-light photocatalytic activity of Ag deposited TiO2 (Ag/TiO2) composites and then contributed to the degradation of organic dyes.

  16. Increasing incidence of diabetes after gestational diabetes

    DEFF Research Database (Denmark)

    Lauenborg, Jeannet; Hansen, Torben; Jensen, Dorte Møller

    2004-01-01

    To study the incidence of diabetes among women with previous diet-treated gestational diabetes mellitus (GDM) in the light of the general increasing incidence of overweight and diabetes and to identify risk factors for the development of diabetes.......To study the incidence of diabetes among women with previous diet-treated gestational diabetes mellitus (GDM) in the light of the general increasing incidence of overweight and diabetes and to identify risk factors for the development of diabetes....

  17. Near field of an oscillating electric dipole and cross-polarization of a collimated beam of light: Two sides of the same coin

    Science.gov (United States)

    Aiello, Andrea; Ornigotti, Marco

    2014-09-01

    We address the question of whether there exists a hidden relationship between the near-field distribution generated by an oscillating electric dipole and the so-called cross-polarization of a collimated beam of light. We find that the answer is affirmative by showing that the complex field distributions occurring in both cases have a common physical origin: the requirement that the electromagnetic fields must be transverse.

  18. The effect of line damping, magneto-optics and parasitic light on the derivation of sunspot vector magnetic fields

    Science.gov (United States)

    Skumanich, A.; Lites, B. W.

    1985-01-01

    The least square fitting of Stokes observations of sunspots using a Milne-Eddington-Unno model appears to lead, in many circumstances, to various inconsistencies such as anomalously large doppler widths and, hence, small magnetic fields which are significantly below those inferred solely from the Zeeman splitting in the intensity profile. It is found that the introduction of additional physics into the model such as the inclusion of damping wings and magneto-optic birefrigence significantly improves the fit to Stokes parameters. Model fits excluding the intensity profile, i.e., of both magnitude as well as spectral shape of the polarization parameters alone, suggest that parasitic light in the intensity profile may also be a source of inconsistencies. The consequences of the physical changes on the vector properties of the field derived from the Fe I lambda 6173 line for the 17 November 1975 spot as well as on the thermodynamic state are discussed. A Doppler width delta lambda (D) - 25mA is bound to be consistent with a low spot temperature and microturbulence, and a damping constant of a = 0.2.

  19. Analysis of light scattering from human breast tissue using a custom dual-optical scanning near-field optical microscope.

    Science.gov (United States)

    Kyle, Jennifer Reiber; Kyle, Michael D; Raghavan, Ravi; Budak, Gurer; Ozkan, Cengiz S; Ozkan, Mihrimah

    2011-03-01

    In this paper we introduce a custom scanning near-field optical microscope (SNOM) that simultaneously collects reflection and transmission near-field images along with topography. This dual-optical SNOM uses a bent probe, which allows for axial reflection imaging, accurate surface scanning, and easy identification of topographic artifacts. Using this novel dual-optical SNOM, we image desiccated and non-desiccated human breast epithelial tissue. By comparing the simultaneous SNOM images, we isolate the effects of tissue morphology and variations in refractive indices on the forward- and back-scattering of light from the tissue. We find that the reduction in back-scattering from tissue, relative to the glass slide, is caused by dense packing of the scattering sites in the cytoplasm (morphology) in the desiccated tissue and a thin-film of water adhering to the glass slide (refractive index) in the non-desiccated tissue sample. Our work demonstrates the potential of our customized dual-optical SNOM system for label-free tissue diagnostics. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. SU-F-T-486: A Simple Approach to Performing Light Versus Radiation Field Coincidence Quality Assurance Using An Electronic Portal Imaging Device (EPID)

    Energy Technology Data Exchange (ETDEWEB)

    Herchko, S; Ding, G [Vanderbilt University, Nashville, TN (United States)

    2016-06-15

    Purpose: To develop an accurate, straightforward, and user-independent method for performing light versus radiation field coincidence quality assurance utilizing EPID images, a simple phantom made of readily-accessible materials, and a free software program. Methods: A simple phantom consisting of a blocking tray, graph paper, and high-density wire was constructed. The phantom was used to accurately set the size of a desired light field and imaged on the electronic portal imaging device (EPID). A macro written for use in ImageJ, a free image processing software, was then use to determine the radiation field size utilizing the high density wires on the phantom for a pixel to distance calibration. The macro also performs an analysis on the measured radiation field utilizing the tolerances recommended in the AAPM Task Group #142. To verify the accuracy of this method, radiochromic film was used to qualitatively demonstrate agreement between the film and EPID results, and an additional ImageJ macro was used to quantitatively compare the radiation field sizes measured both with the EPID and film images. Results: The results of this technique were benchmarked against film measurements, which have been the gold standard for testing light versus radiation field coincidence. The agreement between this method and film measurements were within 0.5 mm. Conclusion: Due to the operator dependency associated with tracing light fields and measuring radiation fields by hand when using film, this method allows for a more accurate comparison between the light and radiation fields with minimal operator dependency. Removing the need for radiographic or radiochromic film also eliminates a reoccurring cost and increases procedural efficiency.

  1. SU-F-T-486: A Simple Approach to Performing Light Versus Radiation Field Coincidence Quality Assurance Using An Electronic Portal Imaging Device (EPID)

    International Nuclear Information System (INIS)

    Herchko, S; Ding, G

    2016-01-01

    Purpose: To develop an accurate, straightforward, and user-independent method for performing light versus radiation field coincidence quality assurance utilizing EPID images, a simple phantom made of readily-accessible materials, and a free software program. Methods: A simple phantom consisting of a blocking tray, graph paper, and high-density wire was constructed. The phantom was used to accurately set the size of a desired light field and imaged on the electronic portal imaging device (EPID). A macro written for use in ImageJ, a free image processing software, was then use to determine the radiation field size utilizing the high density wires on the phantom for a pixel to distance calibration. The macro also performs an analysis on the measured radiation field utilizing the tolerances recommended in the AAPM Task Group #142. To verify the accuracy of this method, radiochromic film was used to qualitatively demonstrate agreement between the film and EPID results, and an additional ImageJ macro was used to quantitatively compare the radiation field sizes measured both with the EPID and film images. Results: The results of this technique were benchmarked against film measurements, which have been the gold standard for testing light versus radiation field coincidence. The agreement between this method and film measurements were within 0.5 mm. Conclusion: Due to the operator dependency associated with tracing light fields and measuring radiation fields by hand when using film, this method allows for a more accurate comparison between the light and radiation fields with minimal operator dependency. Removing the need for radiographic or radiochromic film also eliminates a reoccurring cost and increases procedural efficiency.

  2. Experimental cross sections for light-charged particle production induced by neutrons with energies between 25 and 65 MeV incident on aluminum

    International Nuclear Information System (INIS)

    Benck, S.; Slypen, I.; Meulders, J.P.; Corcalciuc, V.

    2001-01-01

    Experimental double-differential cross sections (d 2 σ/dΩdE) for fast neutron-induced proton, deuteron, triton, and alpha-particle production on aluminum are reported, at several incident neutron energies between 25 and 65 MeV, for outgoing particle energies above the experimental energy thresholds. Angular distributions were measured at laboratory angles between 20 deg. and 160 deg. . Reliable extrapolated spectra are derived for very forward (2.5 deg. and 10 deg. ) and very backward angles (170 deg. and 177.5 deg. ). Based on these experimental data, energy-differential (dσ/dE), angle-differential (dσ/dΩ), and total production cross sections (σ T ) are reported for each outgoing particle

  3. Light particle production in spallation reactions induced by protons of 0.8-2.5 GeV incident kinetic energy

    International Nuclear Information System (INIS)

    Herbach, Claus-Michael; Enke, Michael; Boehm, Andreas

    2002-01-01

    Absolute production cross sections have been measured simultaneously for neutrons and light charged particles in 0.8-2.5 GeV proton induced spallation reactions for a series of target nuclei from aluminum up to uranium. The high detection efficiency both for neutral and charged evaporative particles provides an event-wise access to the amount of projectile energy dissipated into nuclear excitation. Various intra nuclear cascade plus evaporation models have been confronted with the experimental data showing large discrepancies for hydrogen and helium production. (author)

  4. Deciphering biodegradation effects on light hydrocarbons in crude oils using their stable carbon isotopic composition: a case study from the Gullfaks oil field, offshore Norway

    OpenAIRE

    Andrea Vieth-Hillebrand [Vieth; Heinz Wilkes

    2006-01-01

    Compound-specific isotope analysis has become an important tool in environmental studies and is an especially powerful way to evaluate biodegradation of hydrocarbons. Here, carbon isotope ratios of light hydrocarbons were used to characterise in-reservoir biodegradation in the Gullfaks oil field, offshore Norway. Increasing biodegradation, as characterised, for example, by increasing concentration ratios of Pr/n-C17 and Ph/n-C18, and decreasing concentrations of individual light hydrocarbons ...

  5. The Effect of an Offset Polar Cap Dipolar Magnetic Field on the Modeling of the Vela Pulsar's Gamma-Ray Light Curves

    Science.gov (United States)

    Barnard, M.; Venter, C.; Harding, A. K.

    2016-01-01

    We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole B-fields (the latter is characterized by a parameter epsilon), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. The offset-PC dipole B-field mimics deviations from the static dipole (which corresponds to epsilon equals 0). In addition to constant-emissivity geometric models, we also considered a slot gap (SG) E-field associated with the offset-PC dipole B-field and found that its inclusion leads to qualitatively different light curves. Solving the particle transport equation shows that the particle energy only becomes large enough to yield significant curvature radiation at large altitudes above the stellar surface, given this relatively low E-field. Therefore, particles do not always attain the radiation-reaction limit. Our overall optimal light curve fit is for the retarded vacuum dipole field and OG model, at an inclination angle alpha equals 78 plus or minus 1 degree and observer angle zeta equals 69 plus 2 degrees or minus 1 degree. For this B-field, the TPC model is statistically disfavored compared to the OG model. For the static dipole field, neither model is significantly preferred. We found that smaller values of epsilon are favored for the offset-PC dipole field when assuming constant emissivity, and larger epsilon values favored for variable emissivity, but not significantly so. When multiplying the SG E-field by a factor of 100, we found improved light curve fits, with alpha and zeta being closer to best fits from independent studies, as well as curvature radiation reaction at lower altitudes.

  6. Demonstration of a large-size horizontal light-field display based on the LED panel and the micro-pinhole unit array

    Science.gov (United States)

    Yang, Le; Sang, Xinzhu; Yu, Xunbo; Liu, Boyang; Liu, Li; Yang, Shenwu; Yan, Binbin; Du, Jingyan; Gao, Chao

    2018-05-01

    A 54-inch horizontal-parallax only light-field display based on the light-emitting diode (LED) panel and the micro-pinhole unit array (MPUA) is demonstrated. Normally, the perceived 3D effect of the three-dimensional (3D) display with smooth motion parallax and abundant light-field information can be enhanced with increasing the density of viewpoints. However, the density of viewpoints is inversely proportional to the spatial display resolution for the conventional integral imaging. Here, a special MPUA is designed and fabricated, and the displayed 3D scene constructed by the proposed horizontal light-field display is presented. Compared with the conventional integral imaging, both the density of horizontal viewpoints and the spatial display resolution are significantly improved. In the experiment, A 54-inch horizontal light-field display with 42.8° viewing angle based on the LED panel with the resolution of 1280 × 720 and the MPUA is realized, which can provide natural 3D visual effect to observers with high quality.

  7. Properties of light transition radiation of 660 MeV proton inclined incidence (γ=1.7) on a thick nickel plate. II

    International Nuclear Information System (INIS)

    Zrelov, V.P.; Pavlovic, P.; Ruzicka, J.

    1975-01-01

    The basic properties of transition radiation in the visible fraction of the spectrum have been calculated for 660 MeV protons (γ=1.7) obliquely incident on a thick nickel plate in vacuum. The angular distributions of the summary radiation (i.e. the sums of radiations of various polarizations) both 'forward' and 'backward' for different azimuthal planes are presented in tables and diagrams for different particle inclination angles to the separation boundary. The examples of angular distributions of radiation having various polarizations (at the inclination angle of 45 0 ) show that they differ considerably. The spectra of summary radiation are of a monotonous character. The calculations have shown that in a relativistic case the forward radiation is concentrated near the direction of particle motion and backward radiation moves in an opposite direction with respect to that of the particle inclination. The dependence of the total yield of forward and backward transition radiations upon the particle inclination angle is approximately cos 2 psi. (Auth.)

  8. Investigating the effect of personalized dynamic light scenarios on the desk and on the eye : a field study

    NARCIS (Netherlands)

    de Kort, Y.A.W.; Smolders, K.C.H.J.; de Bruijn, R.

    2016-01-01

    Research issue Research on non-image forming effects of light have indicated that optimal light settings are crucial not only for vision, but also for a healthy entrainment of the biological clock and momentary alertness and vitality. This means that in future we should be formulating lighting

  9. Light curve solutions and study of roles of magnetic fields in period variations of the UV Leo system

    Directory of Open Access Journals (Sweden)

    D Manzoori

    2009-12-01

    Full Text Available The solutions of photometric BV light curves for the Algol like system UV Leo were obtained using Wilson-Devinney code. The physical and orbital parameters along with absolute dimensions of the system were determined. It has been found that to best fit the V light curve of the system, assumptions of three dark spots were necessary two on the secondary and one on the primary. The absolute visual magnitudes (Mv of the individual components i.e., primary and secondary were estimated to 4.41 and 4.43, respectively, through the color curve analysis. The period analysis of the system presented elsewhere, indicated a cyclic period change of 12 yr duration, which was attributed to magnetic activity cycle, as a main cause of period variation in the system, through the Applegate mechanism. To verify the Applegate model I preformed calculations of some related parameters barrowed from Apllegate and Kalimeris. Values of all the calculated parameters were in accordance to those obtained for similar systems by Applegate. The differential magnitudes Δ B and Δ V, along with corresponding values of Δ(B-V color index. The cyclic variations in brightness are quite clear. There are three predictions of Applegate's theory concerning effects of cyclic magnetic changes on the period variations, which can be checked through the observations, these are as follows: I The long term variations in mean brightness (at outside of eclipses and cyclic changes of orbital period, vary with the same period. II The active star gets bluer as it gets brightened and/or the brightness and color variations are to be in phase. III Changes in luminosity due to changes in quadrupole moment should be of the order 0.1 mag. All the above mentioned predictions of Applegate’s theory are verified. These results combined with cyclic character of P(E presented elsewhere and also consistency of parameters which are obtained in this paper, led me to conclude that one the main causes of period

  10. Effect of the electric field during annealing of organic light emitting diodes for improving its on/off ratio.

    Science.gov (United States)

    Sharma, Rahul K; Katiyar, Monica; Rao, I V Kameshwar; Unni, K N Narayanan; Deepak

    2016-01-28

    If an organic light emitting diode is to be used as part of a matrix addressed array, it should exhibit low reverse leakage current. In this paper we present a method to improve the on/off ratio of such a diode by simultaneous application of heat and electric field post device fabrication. A green OLED with excellent current efficiency was seen to be suffering from a poor on/off ratio of 10(2). After examining several combinations of annealing along with the application of a reverse bias voltage, the on/off ratio of the same device could be increased by three orders of magnitude, specifically when the device was annealed at 80 °C under reverse bias (-15 V) followed by slow cooling also under the same bias. Simultaneously, the forward characteristics of the device were relatively unaffected. The reverse leakage in the OLED is mainly due to the injection of minority carriers in the hole transport layer (HTL) and the electron transport layer (ETL), in this case, of holes in tris-(8-hydroxyquinoline)aluminum(Alq3) and electrons in 4,4',4''-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA). Hence, to investigate these layers adjacent to the electrodes, we fabricated their single layer devices. The possibility of bulk traps present adjacent to electrodes providing states for injection was ruled out after estimating the trap density both before and after the reverse biased annealing. The temperature independent current in reverse bias ruled out the possibility of thermionic injection. The origin of the reverse bias current is attributed to the availability of interfacial hole levels in Alq3 at the cathode work function level in the as-fabricated device; the suppression of the same being attributed to the fact that these levels in Alq3 are partly removed after annealing under an electric field.

  11. Incidents analysis

    International Nuclear Information System (INIS)

    Francois, P.

    1996-01-01

    We undertook a study programme at the end of 1991. To start with, we performed some exploratory studies aimed at learning some preliminary lessons on this type of analysis: Assessment of the interest of probabilistic incident analysis; possibility of using PSA scenarios; skills and resources required. At the same time, EPN created a working group whose assignment was to define a new approach for analysis of incidents on NPPs. This working group gave thought to both aspects of Operating Feedback that EPN wished to improve: Analysis of significant incidents; analysis of potential consequences. We took part in the work of this group, and for the second aspects, we proposed a method based on an adaptation of the event-tree method in order to establish a link between existing PSA models and actual incidents. Since PSA provides an exhaustive database of accident scenarios applicable to the two most common types of units in France, they are obviously of interest for this sort of analysis. With this method we performed some incident analyses, and at the same time explores some methods employed abroad, particularly ASP (Accident Sequence Precursor, a method used by the NRC). Early in 1994 EDF began a systematic analysis programme. The first, transient phase will set up methods and an organizational structure. 7 figs

  12. Incidents analysis

    Energy Technology Data Exchange (ETDEWEB)

    Francois, P

    1997-12-31

    We undertook a study programme at the end of 1991. To start with, we performed some exploratory studies aimed at learning some preliminary lessons on this type of analysis: Assessment of the interest of probabilistic incident analysis; possibility of using PSA scenarios; skills and resources required. At the same time, EPN created a working group whose assignment was to define a new approach for analysis of incidents on NPPs. This working group gave thought to both aspects of Operating Feedback that EPN wished to improve: Analysis of significant incidents; analysis of potential consequences. We took part in the work of this group, and for the second aspects, we proposed a method based on an adaptation of the event-tree method in order to establish a link between existing PSA models and actual incidents. Since PSA provides an exhaustive database of accident scenarios applicable to the two most common types of units in France, they are obviously of interest for this sort of analysis. With this method we performed some incident analyses, and at the same time explores some methods employed abroad, particularly ASP (Accident Sequence Precursor, a method used by the NRC). Early in 1994 EDF began a systematic analysis programme. The first, transient phase will set up methods and an organizational structure. 7 figs.

  13. Continuous control of light group velocity from subluminal to superluminal propagation with a standing-wave coupling field in a Rb vapor cell

    International Nuclear Information System (INIS)

    Bae, In-Ho; Moon, Han Seb

    2011-01-01

    We present the continuous control of the light group velocity from subluminal to superluminal propagation with an on-resonant standing-wave coupling field in the 5S 1/2 -5P 1/2 transition of the Λ-type system of 87 Rb atoms. When a coupling field was changed from a traveling-wave to a standing-wave field by adjusting the power of a counterpropagating coupling field, the probe pulse propagation continuously transformed from subluminal propagation, due to electromagnetically induced transparency with the traveling-wave coupling field, to superluminal propagation, due to narrow enhanced absorption with the standing-wave coupling field. The group velocity of the probe pulse was measured to be approximately 0.004c to -0.002c as a function of the disparity between the powers of the copropagating and the counterpropagating coupling fields.

  14. Study of novel junctionless Ge n-Tunneling Field-Effect Transistors with lightly doped drain (LDD) region

    Science.gov (United States)

    Liu, Xiangyu; Hu, Huiyong; Wang, Bin; Wang, Meng; Han, Genquan; Cui, Shimin; Zhang, Heming

    2017-02-01

    In this paper, a novel junctionless Ge n-Tunneling Field-Effect Transistors (TFET) structure is proposed. The simulation results show that Ion = 5.5 × 10-5A/μm is achieved. The junctionless device structure enhances Ion effectively and increases the region where significant BTBT occurs, comparing with the normal Ge-nTEFT. The impact of the lightly doped drain (LDD) region is investigated. A comparison of Ion and Ioff of the junctionless Ge n-TFET with different channel doping concentration ND and LDD doping concentration NLDD is studied. Ioff is reduced 1 order of magnitude with the optimized ND and NLDD are 1 × 1018cm-3 and 1 × 1017 cm-3, respectively. To reduce the gate induced drain leakage (GIDL) current, the impact of the sloped gate oxide structure is also studied. By employing the sloped gate oxide structure, the below 60 mV/decade subthreshold swing S = 46.2 mV/decade is achieved at Ion = 4.05 × 10-5A/μm and Ion/Ioff = 5.7 × 106.

  15. Physics at the precipice. The perfection of the unified field theory and the renaissance of the light ether

    International Nuclear Information System (INIS)

    Lichtinger, Manfred

    2010-01-01

    In the first part of the book the author summarizes the present status of modern and classical physics and shows that the contemporary theories ans laws exhibit certain deficiencies and lead to inconsistencies. Partly these deficiencies are removed by relativity theories and quantum theories, but in the other part they concern also the modern theories of the special and general relativity, the big bang, the quantum mechanics, and the quantum gravity. So many objections exist against the relativity theories and the modern cosmology, in which the big bang occupies a central role. To resolve these inconsistencies the author has taken as goal and constructs for this in the second part of the book in a first step three extensions of the conventional GRT, a quantum gravitation theory, a unification of all interactions, and a systematic extension of Einstein's theory of gravitation to arbitrarily high-order nonlinear terms. In a second step he replaces the general relativity by to gravitational theories in the Minkowski space, which leave the special relativity theory unaffected.Because also they exhibit still certain deficiencies, he developes in a third step a ether gravitational theory, a renaissance of the classical light-ether theory, which he then extends finally to the everlasting field theory, which is able to solve nearly all problems presented in the first part of the book.

  16. Height increment of beech and maple depending on the amount of incident light in the Badin primeval forest; Vyskovy prirastok buka a javora v zavislosti od mnozstva dopadajuceho svetla v pralese Badin

    Energy Technology Data Exchange (ETDEWEB)

    Havasova, M [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra regionalnej geografie, 84215 Bratislava (Slovakia)

    2012-04-25

    Processed study is devoted to a dependency of height increase of natural regeneration of beech and maple in Badin primeval forest . In selected site discontinuities there were chosen 2 tran-sects 1 m in width and oriented towards East - West and North - South, passing through the centre of the discontinuity. Heights of beech and maple individuals, as well as the rate of their annual increase (for 2010) were measured there. These data were then transformed to the values of reduced elevation gain. The amount of incident radiation was measured by hemispherical photographs, and we set the values of direct (DSF) and indirect sunlight (ISF). Globally, a negative effect of direct sunlight on the height growth of beech was shown. For height growth of maple no significant effect of different values of ISF or DFS was demonstrated, Justas well as no tran-sect orientation. Beech reached higher gains than maple. Overall bigger gains of the ground wood were achieved on the north side of the discontinuity. Height increment of beech and maple depending on the amount of incident light in the Badin primeval forest. (author)

  17. Involved field radiotherapy (IFRT) versus elective nodal irradiation (ENI) for locally advanced non-small cell lung cancer: a meta-analysis of incidence of elective nodal failure (ENF).

    Science.gov (United States)

    Li, Ruijian; Yu, Liang; Lin, Sixiang; Wang, Lina; Dong, Xin; Yu, Lingxia; Li, Weiyi; Li, Baosheng

    2016-09-21

    The use of involved field radiotherapy (IFRT) has generated concern about the increasing incidence of elective nodal failure (ENF) in contrast to elective nodal irradiation (ENI). This meta-analysis aimed to provide more reliable and up-to-date evidence on the incidence of ENF between IFRT and ENI. We searched three databases for eligible studies where locally advanced non-small cell lung cancer (NSCLC) patients received IFRT or ENI. Outcome of interest was the incidence of ENF. The fixed-effects model was used to pool outcomes across the studies. There were 3 RCTs and 3 cohort studies included with low risk of bias. There was no significant difference in incidence of ENF between IFRT and ENI either among RCTs (RR = 1.38, 95 % CI: 0.59-3.25, p = 0.46) or among cohort studies (RR = 0.99, 95 % CI: 0.46-2.10, p = 0.97). There was also no significant difference in incidence of ENF between IFRT and ENI when RCTs and cohort studies were combined (RR = 1.15, 95 % CI: 0.65-2.01, p = 0.64). I 2 of test for heterogeneity was 0 %. This meta-analysis provides more reliable and stable evidence that there is no significant difference in incidence of ENF between IFRT and ENI.

  18. Hole-exciton interaction induced high field decay of magneto-electroluminescence in Alq{sub 3}-based organic light-emitting diodes at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tingting; Holford, D. F.; Gu, Hang; Kreouzis, T. [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zhang, Sijie, E-mail: Sijie.zhang@scu.edu.cn, E-mail: w.gillin@qmul.ac.uk [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Gillin, W. P., E-mail: Sijie.zhang@scu.edu.cn, E-mail: w.gillin@qmul.ac.uk [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China)

    2016-01-11

    The magnetic field effects on the electroluminescence of aluminium tris-(8-hydroxyqinoline) (Alq{sub 3}) based organic light emitting diodes have been investigated by varying the electron/hole ratio in the emissive layer. Experimental results reveal that a negative high field effect in the magneto-electroluminescence (MEL) can be found in devices with very low triplet exciton concentration at room temperature. This suggests triplet-triplet annihilation cannot be used to explain the negative high field MEL in the Alq{sub 3} system. Our results suggest that hole-exciton interaction may be the origin of the negative high field MEL and also, in parallel with this interaction, there is also the more common positive high field process occurring which has been tentatively attributed to electron-exciton interactions. The competition between these different processes decides the final shape of the MEL at high fields.

  19. Hole-exciton interaction induced high field decay of magneto-electroluminescence in Alq3-based organic light-emitting diodes at room temperature

    Science.gov (United States)

    Zhang, Tingting; Holford, D. F.; Gu, Hang; Kreouzis, T.; Zhang, Sijie; Gillin, W. P.

    2016-01-01

    The magnetic field effects on the electroluminescence of aluminium tris-(8-hydroxyqinoline) (Alq3) based organic light emitting diodes have been investigated by varying the electron/hole ratio in the emissive layer. Experimental results reveal that a negative high field effect in the magneto-electroluminescence (MEL) can be found in devices with very low triplet exciton concentration at room temperature. This suggests triplet-triplet annihilation cannot be used to explain the negative high field MEL in the Alq3 system. Our results suggest that hole-exciton interaction may be the origin of the negative high field MEL and also, in parallel with this interaction, there is also the more common positive high field process occurring which has been tentatively attributed to electron-exciton interactions. The competition between these different processes decides the final shape of the MEL at high fields.

  20. Theoretical analysis of multiple quantum-well, slow-light devices under applied external fields using a fully analytical model in fractional dimension

    Energy Technology Data Exchange (ETDEWEB)

    Kohandani, R; Kaatuzian, H [Photonics Research Laboratory, Electrical Engineering Department, AmirKabir University of Technology, Hafez Ave., Tehran (Iran, Islamic Republic of)

    2015-01-31

    We report a theoretical study of optical properties of AlGaAs/GaAs multiple quantum-well (MQW), slow-light devices based on excitonic population oscillations under applied external magnetic and electric fields using an analytical model for complex dielectric constant of Wannier excitons in fractional dimension. The results are shown for quantum wells (QWs) of different width. The significant characteristics of the exciton in QWs such as exciton energy and exciton oscillator strength (EOS) can be varied by application of external magnetic and electric fields. It is found that a higher bandwidth and an appropriate slow-down factor (SDF) can be achieved by changing the QW width during the fabrication process and by applying magnetic and electric fields during device functioning, respectively. It is shown that a SDF of 10{sup 5} is obtained at best. (slowing of light)

  1. Light propagation in the gravitational field of N arbitrarily moving bodies in the 1.5PN approximation for high-precision astrometry

    Science.gov (United States)

    Zschocke, Sven

    2016-05-01

    High-precision astrometry on sub-micro-arcsecond level in angular resolution requires accurate determination of the trajectory of a light-signal from the celestial light source through the gravitational field of the Solar System toward the observer. In this investigation the light trajectory in the gravitational field of N moving bodies is determined in the 1.5 post-Newtonian approximation. In the approach presented two specific issues of particular importance are accounted for: (1) According to the recommendations of International Astronomical Union, the metric of the Solar System is expressed in terms of intrinsic mass-multipoles and intrinsic spin-multipoles of the massive bodies, allowing for arbitrary shape, inner structure and rotational motion of the massive bodies of the Solar System. (2) The Solar System bodies move along arbitrary world lines which can later be specified by Solar System ephemeris. The presented analytical solution for light trajectory is a primary requirement for extremely high-precision astrometry on sub-micro-arcsecond level of accuracy and associated massive computations in astrometric data reduction. An estimation of the numerical magnitude for time delay and light deflection of the leading multipoles is given.

  2. A search for light gluinos, and, Heavy quark effective field theory and B-physics with applications to the collider detector at Fermilab

    International Nuclear Information System (INIS)

    Cakir, M.B.

    1993-01-01

    In the first part of this dissertation a search for light gluinos in the 0(1 GeV) region - especially in radiative decays of vector quarkonia - is presented. It is shown that light gluinos have not been excluded by experiments to date. In fact some evidence contrary to that fact is presented. In the second part the recent Heavy Quark Effective Field Theory methods are used in calculating rare decays of vector and pseudoscalar mesons of b-quarks. Applications to the Collider Detector at Fermilab environment are discussed

  3. Influence of Solid Target Reflectivity and Incident Angle on Depolarization Ratio and Reflected Energy from Polarized Lights: Experimental Results of the May 2008 Field Trial

    Science.gov (United States)

    2009-11-01

    enviromental targets . . . . . . . . . . . . 45 Figure 25: Relative reectivity of environmental targets . . . . . . . . . . . . 46 Figure 26: Relationship...Environmental targets and position of the center . . . . . . . . . . 41 Table 11: Depolarization ratio of enviromental targets...42 Table 12: Relative reectivity results of enviromental targets . . . . . . . . . 42 Table 13: Sand papers and position of the center

  4. Near-field collimation of light carrying orbital angular momentum with bull's-eye-assisted plasmonic coaxial waveguides.

    Science.gov (United States)

    Pu, Mingbo; Ma, Xiaoliang; Zhao, Zeyu; Li, Xiong; Wang, Yanqin; Gao, Hui; Hu, Chenggang; Gao, Ping; Wang, Changtao; Luo, Xiangang

    2015-07-10

    The orbital angular momentum (OAM) of light, as an emerging hotspot in optics and photonics, introduces many degrees of freedom for applications ranging from optical communication and quantum processing to micromanipulation. To achieve a high degree of integration, optical circuits for OAM light are essential, which are, however, challenging in the optical regime owing to the lack of well-developed theory. Here we provide a scheme to guide and collimate the OAM beam at the micro- and nano-levels. The coaxial plasmonic slit was exploited as a naturally occurring waveguide for light carrying OAM. Concentric grooves etched on the output surface of the coaxial waveguide were utilized as a plasmonic metasurface to couple the OAM beam to free space with greatly increased beam directivity. Experimental results at λ = 532 nm validated the novel transportation and collimating effect of the OAM beam. Furthermore, dynamic tuning of the topological charges was demonstrated by using a liquid crystal spatial light modulator (SLM).

  5. Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

    Science.gov (United States)

    Lee, Dukhyung; Kim, Dai-Sik

    2016-01-01

    We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

  6. Self-action of continuous laser radiation and Pearcey diffraction in a water suspension with light-absorbing particles

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya.; Maksimyak, P. P.

    2014-01-01

    -diffraction of the incident light, here being strongly sensitive to the medium position with respect to the focus. This technique, based on the complex spatial structure of both the incident and the diffracted fields, can be employed for the detection and measurement of weak non-linearities....

  7. Assessment of mouse anxiety-like behavior in the light-dark box and open-field arena: role of equipment and procedure.

    Science.gov (United States)

    Kulesskaya, Natalia; Voikar, Vootele

    2014-06-22

    Light-dark box and open field are conventional tests for assessment of anxiety-like behavior in the laboratory mice, based on approach-avoidance conflict. However, except the basic principles, variations in the equipment and procedures are very common. Therefore, contribution of certain methodological issues in different settings was investigated. Three inbred strains (C57BL/6, 129/Sv, DBA/2) and one outbred stock (ICR) of mice were used in the experiments. An effect of initial placement of mice either in the light or dark compartment was studied in the light-dark test. Moreover, two tracking systems were applied - position of the animals was detected either by infrared sensors in square box (1/2 dark) or by videotracking in rectangular box (1/3 dark). Both approaches revealed robust and consistent strain differences in the exploratory behavior. In general, C57BL/6 and ICR mice showed reduced anxiety-like behavior as compared to 129/Sv and DBA/2 strains. However, the latter two strains differed markedly in their behavior. DBA/2 mice displayed high avoidance of the light compartment accompanied by thigmotaxis, whereas the hypoactive 129 mice spent a significant proportion of time in risk-assessment behavior at the opening between two compartments. Starting from the light side increased the time spent in the light compartment and reduced the latency to the first transition. In the open field arena, black floor promoted exploratory behavior - increased time and distance in the center and increased rearing compared to white floor. In conclusion, modifications of the apparatus and procedure had significant effects on approach-avoidance behavior in general whereas the strain rankings remained unaffected. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. [Effect of genotype and day or night time of testing on mice behavior in the light-dark box and the open-field tests].

    Science.gov (United States)

    Morozova, M V; Kulikov, A V

    2010-01-01

    The light-dark box (LDB) and the open-field (OF) tests are widespread experimental models for studying locomotion and anxiety in laboratory rats and mice. The fact that rodents are nocturnal animals and more active at night raises a critical question of whether behavioral experiments carried out in the light phase are methodologically correct. Parameters of behavior of four mouse strains (C57BL/6J, DBA2/J, AKR/J and CBA/LacJ) in the light-dark box and open-field tests in the light and dark phases were compared. No significant influence of the phase of testing on anxiety in LDB and OF tests was revealed. In the OF test CBA mice showed increased locomotor activity, whereas AKR and C57BL/6 mice showed increased defecation in the dark phase. It was concluded that: 1) the phase of testing is not crucial for the expression of anxiety in LDB and OF; 2) the sensitivity to the phase of testing depends on the genotype; 3) the indices of behavior in the genotypes sensitive to the phase of testing (locomotion in the CBA and defecation in the AKR and C57BL/6 mouse strains) are increased in the dark phase.

  9. Producing Light Oil from a Frozen Reservoir: Reservoir and Fluid Characterization of Umiat Field, National Petroleum Reserve, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Hanks, Catherine

    2012-12-31

    Umiat oil field is a light oil in a shallow, frozen reservoir in the Brooks Range foothills of northern Alaska with estimated oil-in-place of over 1 billion barrels. Umiat field was discovered in the 1940’s but was never considered viable because it is shallow, in the permafrost, and far from any transportation infrastructure. The advent of modern drilling and production techniques has made Umiat and similar fields in northern Alaska attractive exploration and production targets. Since 2008 UAF has been working with Renaissance Alaska Inc. and, more recently, Linc Energy, to develop a more robust reservoir model that can be combined with rock and fluid property data to simulate potential production techniques. This work will be used to by Linc Energy as they prepare to drill up to 5 horizontal wells during the 2012-2013 drilling season. This new work identified three potential reservoir horizons within the Cretaceous Nanushuk Formation: the Upper and Lower Grandstand sands, and the overlying Ninuluk sand, with the Lower Grandstand considered the primary target. Seals are provided by thick interlayered shales. Reserve estimates for the Lower Grandstand alone range from 739 million barrels to 2437 million barrels, with an average of 1527 million bbls. Reservoir simulations predict that cold gas injection from a wagon-wheel pattern of multilateral injectors and producers located on 5 drill sites on the crest of the structure will yield 12-15% recovery, with actual recovery depending upon the injection pressure used, the actual Kv/Kh encountered, and other geologic factors. Key to understanding the flow behavior of the Umiat reservoir is determining the permeability structure of the sands. Sandstones of the Cretaceous Nanushuk Formation consist of mixed shoreface and deltaic sandstones and mudstones. A core-based study of the sedimentary facies of these sands combined with outcrop observations identified six distinct facies associations with distinctive permeability

  10. Assessing anxiety in C57BL/6J mice: a pharmacological characterization of the open-field and light/dark tests.

    Science.gov (United States)

    Heredia, Luis; Torrente, Margarita; Colomina, María T; Domingo, José L

    2014-01-01

    In order to assess anxiety in mammals various tests and species are currently available. These current assays measure changes in anxiety-like behaviors. The open-field and the light/dark are anxiety tests based on the spontaneous behavior of the animals, with C57BL/6J mice being a frequently used strain in behavioral studies. However, the suitability of this strain as a choice in anxiety studies has been questioned. In this study, we performed two pharmacological characterizations of this strain in both the open-field and the light/dark tests. We examined the changes in the anxiety-like behaviors of C57BL/6J mice exposed to chlordiazepoxide (CDP), an anxiolytic drug, at doses of 5 and 10 mg/kg, picrotoxine (PTX), an anxiogenic drug, at doses of 0.5 and 1 mg/kg, and methylphenidate (MPH), a psychomotor stimulant drug, at doses of 5 and 10 mg/kg, in a first experiment. In a second experiment, we tested CDP at 2.5 mg/kg, PTX at 2 mg/kg and MPH at 2.5 mg/kg. Results showed an absence of anxiolytic-like effects of CDP in open-field and light/dark tests. Light/dark test was more sensitive to the anxiogenic effects of PTX than the open-field test. Finally, a clear anxiogenic effect of MPH was observed in the two tests. Although C57BL/6J mice could not be a sensitive model to study anxiolytic effects in pharmacological or behavioral interventions, it might be a suitable model to test anxiogenic effects. Further studies are necessary to corroborate these results. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Structure-based optics of centric diatom frustules: modulation of the in vivo light field for efficient diatom photosynthesis.

    Science.gov (United States)

    Goessling, Johannes W; Su, Yanyan; Cartaxana, Paulo; Maibohm, Christian; Rickelt, Lars F; Trampe, Erik C L; Walby, Sandra L; Wangpraseurt, Daniel; Wu, Xia; Ellegaard, Marianne; Kühl, Michael

    2018-07-01

    The optical properties of diatom silicate frustules inspire photonics and nanotechnology research. Whether light interaction with the nano-structure of the frustule also affects diatom photosynthesis has remained unclear due to lack of information on frustule optical properties under more natural conditions. Here we demonstrate that the optical properties of the frustule valves in water affect light harvesting and photosynthesis in live cells of centric diatoms (Coscinodiscus granii). Microscale cellular mapping of photosynthesis around localized spot illumination demonstrated optical coupling of chloroplasts to the valve wall. Photonic structures of the three-layered C. granii valve facilitated light redistribution and efficient photosynthesis in cell regions distant from the directly illuminated area. The different porous structure of the two sides of the valve exhibited photon trapping and forward scattering of blue light enhancing photosynthetic active radiation inside the cell. Photonic structures of diatom frustules thus alter the cellular light field with implications on diatom photobiology. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  12. A series approximation model for optical light transport and output intensity field distribution in large aspect ratio cylindrical scintillation crystals

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, Benjamin John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-09

    A series approximation has been derived for the transport of optical photons within a cylindrically symmetric light pipe and applied to the task of evaluating both the origin and angular distribution of light reaching the output plane. This analytic expression finds particular utility in first-pass photonic design applications since it may be evaluated at a very modest computational cost and is readily parameterized for relevant design constraints. It has been applied toward quantitative exploration of various scintillation crystal preparations and their impact on both quantum efficiency and noise, reproducing sensible dependencies and providing physical justification for certain gamma ray camera design choices.

  13. Evolution of the field quantum entropy and entanglement in a system of multimode light field interacting resonantly with a two-level atom through N_j-degenerate N~Σ-photon process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.

  14. Near-field collimation of light carrying orbital angular momentum with bull’s-eye-assisted plasmonic coaxial waveguides

    Science.gov (United States)

    Pu, Mingbo; Ma, Xiaoliang; Zhao, Zeyu; Li, Xiong; Wang, Yanqin; Gao, Hui; Hu, Chenggang; Gao, Ping; Wang, Changtao; Luo, Xiangang

    2015-07-01

    The orbital angular momentum (OAM) of light, as an emerging hotspot in optics and photonics, introduces many degrees of freedom for applications ranging from optical communication and quantum processing to micromanipulation. To achieve a high degree of integration, optical circuits for OAM light are essential, which are, however, challenging in the optical regime owing to the lack of well-developed theory. Here we provide a scheme to guide and collimate the OAM beam at the micro- and nano-levels. The coaxial plasmonic slit was exploited as a naturally occurring waveguide for light carrying OAM. Concentric grooves etched on the output surface of the coaxial waveguide were utilized as a plasmonic metasurface to couple the OAM beam to free space with greatly increased beam directivity. Experimental results at λ = 532 nm validated the novel transportation and collimating effect of the OAM beam. Furthermore, dynamic tuning of the topological charges was demonstrated by using a liquid crystal spatial light modulator (SLM).

  15. fields

    Directory of Open Access Journals (Sweden)

    Brad J. Arnold

    2014-07-01

    Full Text Available Surface irrigation, such as flood or furrow, is the predominant form of irrigation in California for agronomic crops. Compared to other irrigation methods, however, it is inefficient in terms of water use; large quantities of water, instead of being used for crop production, are lost to excess deep percolation and tail runoff. In surface-irrigated fields, irrigators commonly cut off the inflow of water when the water advance reaches a familiar or convenient location downfield, but this experience-based strategy has not been very successful in reducing the tail runoff water. Our study compared conventional cutoff practices to a retroactively applied model-based cutoff method in four commercially producing alfalfa fields in Northern California, and evaluated the model using a simple sensor system for practical application in typical alfalfa fields. These field tests illustrated that the model can be used to reduce tail runoff in typical surface-irrigated fields, and using it with a wireless sensor system saves time and labor as well as water.

  16. Study of the two body dissociation of light nuclei in nuclear fields. Progress report, January 1, 1976--December 31, 1976

    International Nuclear Information System (INIS)

    Kirk, P.N.; Huggett, R.W.

    The object of the experiment is to measure the frequency with which nucleons within a parent nucleus coalesce into clusters. The experiment is being carried out at the Bevatron with heavy ion beams of 2.1 GeV kinetic energy per nucleon. The extracted heavy ion beam is directed onto a target in which many interactions occur. The interactions of interest are those in which the incident nucleus fragments into two daughter nuclei. These events are selected from the background by scintillation counters and associated fast electronics

  17. Calculated Hanle transmission and absorption spectra of the 87Rb D1 line with residual magnetic field for arbitrarily polarized light

    International Nuclear Information System (INIS)

    Noh, Heung-Ryoul; Moon, Han Seb

    2010-01-01

    This paper reports a theoretical study on the transmission spectra of an arbitrarily polarized laser beam through a rubidium cell with or without a buffer gas in Hanle-type coherent population trapping (CPT). This study examined how laser polarization, transverse magnetic field, and collisions with buffer gas affects the spectrum. The transmission spectrum due to CPT and the absorption spectrum due to the level crossing absorption (LCA) were calculated according to the laser polarization. The results show that the LCA is strongly dependent on the transverse magnetic field and interaction time of the atoms with a laser light via collisions with the buffer gas. In addition, the spectral shape of the calculated Hanle spectrum is closely related to the direction between the (stray) transverse magnetic field and polarization of the laser.

  18. Effect of 60-Hz magnetic fields on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae.

    Science.gov (United States)

    Ager, D D; Radul, J A

    1992-12-01

    The purpose of this study was to examine the effect of extremely low frequency (ELF) magnetic fields on the induction of genetic damage. In general, mutational studies involving ELF magnetic fields have proven negative. However, studies examining sister-chromatid exchange and chromosome aberrations have yielded conflicting results. In this study, we have examined whether 60-Hz magnetic fields are capable of inducing mutation or mitotic recombination in the yeast Saccharomyces cerevisiae. In addition we determined whether magnetic fields were capable of altering the genetic response of S. cerevisiae to UV (254 nm). We measured the frequencies of induced mutation, gene conversion and reciprocal mitotic crossing-over for exposures to magnetic fields alone (1 mT) or in combination with various UV exposures (2-50 J/m2). These experiments were performed using a repair-proficient strain (RAD+), as well as a strain of yeast (rad3) which is incapable of excising UV-induced thymine dimers. Magnetic field exposures did not induce mutation, gene conversion or reciprocal mitotic crossing-over in either of these strains, nor did the fields influence the frequencies of UV-induced genetic events.

  19. Radiation damage of light guide fibers in gamma radiation field - on-line monitoring of absorption centers formation

    International Nuclear Information System (INIS)

    Blaha, J.; Simane, C.; Finger, M.; Slunecka, M.; Finger, M. Jr.; Sluneckova, V.; Janata, A.; Vognar, M.; Sulc, M.

    2004-01-01

    The kinetics of radiation-induced changes of absorption coefficient was studied by online transmission spectra measurement for two different Kuraray light guide fibers. The samples were irradiated by bremsstrahlung gamma radiation, dose rates were from 2 Gy/s to 25 Gy/s. The kinetic coefficients both for absorption centers formation and for recovery processes were calculated. Good agreement of experimental data and simple one-short-lived absorption center model were received for radiation-hard light guide Kuraray (KFC). The more complicated process was observed on Kuraray (PSM) clear fiber. It was caused by the reaction of the oxygen dissolved in fiber and created radicals. The results are very useful for prediction of an optical fibers response in conditions of new nuclear and particle physics experiments. (author)

  20. Time-resolved ultraviolet near-field scanning optical microscope for characterizing photoluminescence lifetime of light-emitting devices.

    Science.gov (United States)

    Park, Kyoung-Duck; Jeong, Hyun; Kim, Yong Hwan; Yim, Sang-Youp; Lee, Hong Seok; Suh, Eun-Kyung; Jeong, Mun Seok

    2013-03-01

    We developed a instrument consisting of an ultraviolet (UV) near-field scanning optical microscope (NSOM) combined with time-correlated single photon counting, which allows efficient observation of temporal dynamics of near-field photoluminescence (PL) down to the sub-wavelength scale. The developed time-resolved UV NSOM system showed a spatial resolution of 110 nm and a temporal resolution of 130 ps in the optical signal. The proposed microscope system was successfully demonstrated by characterizing the near-field PL lifetime of InGaN/GaN multiple quantum wells.

  1. Investigations of reactions between pure refractory metals and light gases with the field ion microscope and atom probe

    International Nuclear Information System (INIS)

    Krautz, E.; Haiml, G.

    1989-01-01

    The initial stages of selected reactions of the refractory metals tungsten, niobium and tantalum with hydrogen, oxygen, nitrogen and methane have been studied with the field ion microscope in atomic resolution whereby the composition of single net planes converages and surface zones could absolutely be analyzed with the atom probe by using field desorption under defined conditions at low temperatures. 14 refs., 9 figs. (Author)

  2. Effect of interdiffusion and external magnetic field on electronic states and light absorption in Gaussian-shaped double quantum ring

    Science.gov (United States)

    Aziz-Aghchegala, V. L.; Mughnetsyan, V. N.; Kirakosyan, A. A.

    2018-02-01

    The effect of interdiffusion and magnetic field on confined states of electron and heavy hole as well as on interband absorption spectrum in a Ga1-xAlxAs/GaAs Gaussian-shaped double quantum ring are investigated. It is shown that both interdiffusion and magnetic field lead to the change of the charge carriers' quantum states arrangement by their energies. The oscillating behavior of the electron ground state energy as a function of magnetic field induction gradually disappears with the increase of diffusion parameter due to the enhanced tunneling of electron to the central region of the ring. For the heavy hole the ground state energy oscillations are not observable in the region of the values of magnetic field induction B = 0 - 10 T . For considered transitions both the magnetic field and the interdiffusion lead to a blue-shift of the absorption spectrum and to decreasing of the absorption intensity. The obtained results indicate on the opportunity of purposeful manipulation of energy states and absorption spectrum of a Gaussian-shaped double quantum ring by means of the post growth annealing and the external magnetic field.

  3. Utilization of Field Enhancement in Plasmonic Waveguides for Subwavelength Light-Guiding, Polarization Handling, Heating, and Optical Sensing.

    Science.gov (United States)

    Dai, Daoxin; Wu, Hao; Zhang, Wei

    2015-10-09

    Plasmonic nanostructures have attracted intensive attention for many applications in recent years because of the field enhancement at the metal/dielectric interface. First, this strong field enhancement makes it possible to break the diffraction limit and enable subwavelength optical waveguiding, which is desired for nanophotonic integrated circuits with ultra-high integration density. Second, the field enhancement in plasmonic nanostructures occurs only for the polarization mode whose electric field is perpendicular to the metal/dielectric interface, and thus the strong birefringence is beneficial for realizing ultra-small polarization-sensitive/selective devices, including polarization beam splitters, and polarizers. Third, plasmonic nanostructures provide an excellent platform of merging electronics and photonics for some applications, e.g., thermal tuning, photo-thermal detection, etc. Finally, the field enhancement at the metal/dielectric interface helps a lot to realize optical sensors with high sensitivity when introducing plasmonic nanostrutures. In this paper, we give a review for recent progresses on the utilization of field enhancement in plasmonic nanostructures for these applications, e.g., waveguiding, polarization handling, heating, as well as optical sensing.

  4. Utilization of Field Enhancement in Plasmonic Waveguides for Subwavelength Light-Guiding, Polarization Handling, Heating, and Optical Sensing

    Directory of Open Access Journals (Sweden)

    Daoxin Dai

    2015-10-01

    Full Text Available Plasmonic nanostructures have attracted intensive attention for many applications in recent years because of the field enhancement at the metal/dielectric interface. First, this strong field enhancement makes it possible to break the diffraction limit and enable subwavelength optical waveguiding, which is desired for nanophotonic integrated circuits with ultra-high integration density. Second, the field enhancement in plasmonic nanostructures occurs only for the polarization mode whose electric field is perpendicular to the metal/dielectric interface, and thus the strong birefringence is beneficial for realizing ultra-small polarization-sensitive/selective devices, including polarization beam splitters, and polarizers. Third, plasmonic nanostructures provide an excellent platform of merging electronics and photonics for some applications, e.g., thermal tuning, photo-thermal detection, etc. Finally, the field enhancement at the metal/dielectric interface helps a lot to realize optical sensors with high sensitivity when introducing plasmonic nanostrutures. In this paper, we give a review for recent progresses on the utilization of field enhancement in plasmonic nanostructures for these applications, e.g., waveguiding, polarization handling, heating, as well as optical sensing.

  5. X-ray and visible light transmission as two-dimensional, full-field moisture-sensing techniques: A preliminary comparison

    International Nuclear Information System (INIS)

    Tidwell, V.C.; Glass, R.J.

    1992-01-01

    Two independent high-resolution moisture-sensing techniques, x-ray absorption and light transmission, have been developed for use in two-dimensional, thin-slab experimental systems. The techniques yield full-field measurement capabilities with exceptional resolution of moisture content in time and space. These techniques represent powerful tools for the experimentalist to investigate processes governing unsaturated flow and transport through fractured and nonfractured porous media. Evaluation of these techniques has been accomplished by direct comparison of data obtained by means of the x-ray and light techniques as well as comparison with data collected by gravimetric and gamma-ray densitometry techniques. Results show excellent agreement between data collected by the four moisture-content measurement techniques. This program was established to support the Yucca Mountain Site Characterization Project

  6. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    Science.gov (United States)

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  7. Far field photoluminescence imaging of single AlGaN nanowire in the sub-wavelength scale using confinement of polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Sivadasan, A.K.; Dhara, Sandip [Nanomaterials and Sensors Section, Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam (India); Sardar, Manas [Theoretical Studies Section, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2017-03-15

    Till now the nanoscale focusing and imaging in the sub-diffraction limit is achieved mainly with the help of plasmonic field enhancement by confining the light assisted with noble metal nanostructures. Using far field imaging technique, we have recorded polarized spectroscopic photoluminescence (PL) imaging of a single AlGaN nanowire (NW) of diameter ∝100 nm using confinement of polarized light. It is found that the PL from a single NW is influenced by the proximity to other NWs. The PL intensity is proportional to 1/(l x d), where l and d are the average NW length and separation between the NWs, respectively. We suggest that the proximity induced PL intensity enhancement can be understood by assuming the existence of reasonably long lived photons in the intervening space between the NWs. A nonzero non-equilibrium population of such photons may cause stimulated emission leading to the enhancement of PL emission with the intensity proportional to 1/(l x d). The enhancement of PL emission facilitates far field spectroscopic imaging of a single semiconductor AlGaN NW of sub-wavelength dimension. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Phenotyping of field-grown wheat in the UK highlights contribution of light response of photosynthesis and flag leaf longevity to grain yield.

    Science.gov (United States)

    Carmo-Silva, Elizabete; Andralojc, P John; Scales, Joanna C; Driever, Steven M; Mead, Andrew; Lawson, Tracy; Raines, Christine A; Parry, Martin A J

    2017-06-15

    Improving photosynthesis is a major target for increasing crop yields and ensuring food security. Phenotyping of photosynthesis in the field is critical to understand the limits to crop performance in agricultural settings. Yet, detailed phenotyping of photosynthetic traits is relatively scarce in field-grown wheat, with previous studies focusing on narrow germplasm selections. Flag leaf photosynthetic traits, crop development, and yield traits were compared in 64 field-grown wheat cultivars in the UK. Pre-anthesis and post-anthesis photosynthetic traits correlated significantly and positively with grain yield and harvest index (HI). These traits included net CO2 assimilation measured at ambient CO2 concentrations and a range of photosynthetic photon flux densities, and traits associated with the light response of photosynthesis. In most cultivars, photosynthesis decreased post-anthesis compared with pre-anthesis, and this was associated with decreased Rubisco activity and abundance. Heritability of photosynthetic traits suggests that phenotypic variation can be used to inform breeding programmes. Specific cultivars were identified with traits relevant to breeding for increased crop yields in the UK: pre-anthesis photosynthesis, post-anthesis photosynthesis, light response of photosynthesis, and Rubisco amounts. The results indicate that flag leaf longevity and operating photosynthetic activity in the canopy can be further exploited to maximize grain filling in UK bread wheat. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  9. Strong Transverse Photosphere Magnetic Fields and Twist in Light Bridge Dividing Delta Sunspot of Active Region 12673

    OpenAIRE

    Wang, Haimin; Yurchyshyn, Vasyl; Liu, Chang; Ahn, Kwangsu; Toriumi, Shin; Cao, Wenda

    2018-01-01

    Solar Active Region (AR) 12673 is the most flare productive AR in the solar cycle 24. It produced four X-class flares including the X9.3 flare on 06 September 2017 and the X8.2 limb event on 10 September. Sun and Norton (2017) reported that this region had an unusual high rate of flux emergence, while Huang et al. (2018) reported that the X9.3 flare had extremely strong white-light flare emissions. Yang at al. (2017) described the detailed morphological evolution of this AR. In this report, w...

  10. Soil spectral measurements in the field: problems and solutions in light of the GEO-CARDEL project

    Science.gov (United States)

    Dor, E. Ben; Granot, Amihai

    2017-09-01

    The GEO-CRADEL project aims to establish several knowhow for GEO applications. One of them is food security in which soil spectroscopy plays a major role. To that end we had developed a new assembly for measuring surface reflectance in the field. This was done in order to fill the gap between laboratory and field soil spectral measurements. This device, named SoilPRO (SP) can be connected to any field spectrometer fiber's tip and used to measure representative and undisturbed surfaces of different soil types. The SoilPRO's performance was evaluated against laboratory measurements under optimal conditions and demonstrated high performance in the field. As the SP measurement is not dependent on main factors such as the sun's radiation, atmospheric variations, operator stability or measurement geometry, and it does not disturb the surface being measured, its measurement can be used with laboratory soil spectral data (SSL). To that end the SSL that is generated under the GEO-CARDEL project is now can be used for agro- application in the field.

  11. Experimental irradiation of the rat ureter: The effects of field size and the presence of contrast medium on incidence and latency of hydronephrosis

    International Nuclear Information System (INIS)

    Knowles, J.F.; Trott, K.R.

    1987-01-01

    Following X-irradiation of a 1.5 cm length of rat ureter, hydronephrosis developed after doses down to 10 Gy. The estimated ED 50 was 11.8 Gy. In the dose range 37.4 Gy to 17.5 Gy there was a significant increase in latency with decreasing dose, but at lower doses the latency did not increase further. Reducing the length of ureter irradiated to 0.5 cm or 0.8 cm caused a decrease in incidence of hydronephrosis and longer latency periods. The ED 50 for rats iradiated to 0.5 cm of ureter was 29.6 Gy. The possibility that secondary radiation produced as a result of interaction between X-radiation and iodinated contrast medium might affect the radiation induction of hydronephrosis was investigated. No difference was found between groups of rats irradiated with or without injection of contrast media. 39 refs.; 4 figs

  12. THE LIGHT CURVE AND INTERNAL MAGNETIC FIELD OF THE MODE-SWITCHING PULSAR PSR B0943+10

    Energy Technology Data Exchange (ETDEWEB)

    Storch, Natalia I.; Lai, Dong [Center for Space Research, Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Ho, Wynn C. G. [Mathematical Sciences and STAG Research Centre, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Bogdanov, Slavko [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Heinke, Craig O. [Department of Physics, University of Alberta, CCIS 4-181, Edmonton, AB, T6G 2E1 (Canada)

    2014-07-10

    A number of radio pulsars exhibit intriguing mode-switching behavior. Recent observations of PSR B0943+10 revealed correlated radio and X-ray mode switches, providing a new avenue for understanding this class of objects. The large X-ray pulse fraction observed during the radio-quiet phase (Q-mode) was previously interpreted as a result of changing obscuration of X-rays by dense magnetosphere plasma. We show that the large X-ray pulse fraction can be explained by including the beaming effect of a magnetic atmosphere, while remaining consistent with the dipole field geometry constrained by radio observations. We also explore a more extreme magnetic field configuration, where a magnetic dipole displaced from the center of the star produces two magnetic polar caps of different sizes and magnetic field strengths. These models are currently consistent with data in radio and X-rays and can be tested or constrained by future X-ray observations.

  13. [National system of protection against electromagnetic fields 0 Hz-300 GHz in the light of current legal regulations].

    Science.gov (United States)

    Aniołczyk, Halina

    2006-01-01

    Exposure to electromagnetic fields (EMF) occurs when man is exposed to the effect of electric, magnetic and electromagnetic fields and contact currents different from those resulting from physiological processes in the organism or other natural phenomena. In Poland, the system of protection against EMF has been functioning for over 35 years. In 2001, when the Minister of Labor and Social Policy issued the regulation introducing the maximum admissible intensities (MAI) for electromagnetic fields and radiation within the range of 0 Hz-300 GHz, the system was directed mainly towards evaluation of exposure to EMF occurring in the occupational environment. The system is linked via MAI values with human protection in the natural environment. In this paper, the background, principles and the range of the national system of protection against EMF and its monitoring are presented. The project of implementation of EU directives, following Poland's accession to the European Union is also discussed.

  14. Influence of thermal light correlations on photosynthetic structures

    Science.gov (United States)

    de Mendoza, Adriana; Manrique, Pedro; Caycedo-Soler, Felipe; Johnson, Neil F.; Rodríguez, Ferney J.; Quiroga, Luis

    2014-03-01

    The thermal light from the sun is characterized by both classical and quantum mechanical correlations. These correlations have left a fingerprint on the natural harvesting structures developed through five billion years of evolutionary pressure, specially in photosynthetic organisms. In this work, based upon previous extensive studies of spatio-temporal correlations of light fields, we hypothesize that structures involving photosensitive pigments like those present in purple bacteria vesicles emerge as an evolutionary response to the different properties of incident light. By using burstiness and memory as measures that quantify higher moments of the photon arrival statistics, we generate photon-time traces. They are used to simulate absorption on detectors spatially extended over regions comparable to these light fields coherence length. Finally, we provide some insights into the connection between these photo-statistical features with the photosynthetic membrane architecture and the lights' spatial correlation. Facultad de Ciencias Uniandes.

  15. Detection of nanoplastics in food by asymmetric flow field-flow fractionation coupled to multi-angle light scattering: possibilities, challenges and analytical limitations

    DEFF Research Database (Denmark)

    Correia, Manuel; Löschner, Katrin

    2018-01-01

    We tested the suitability of asymmetric flow field-flow fractionation (AF4) coupled to multi-angle light scattering (MALS) for detection of nanoplastics in fish. A homogenized fish sample was spiked with 100 nm polystyrene nanoparticles (PSNPs) (1.3 mg/g fish). Two sample preparation strategies...... were tested: acid digestion and enzymatic digestion with proteinase K. Both procedures were found suitable for degradation of the organic matrix. However, acid digestion resulted in large PSNPs aggregates/agglomerates (> 1 μm). The presence of large particulates was not observed after enzymatic...

  16. Effect of field view size and lighting on unique-hue selection using Natural Color System object colors.

    Science.gov (United States)

    Shamey, Renzo; Zubair, Muhammad; Cheema, Hammad

    2015-08-01

    The aim of this study was twofold, first to determine the effect of field view size and second of illumination conditions on the selection of unique hue samples (UHs: R, Y, G and B) from two rotatable trays, each containing forty highly chromatic Natural Color System (NCS) samples, on one tray corresponding to 1.4° and on the other to 5.7° field of view size. UH selections were made by 25 color-normal observers who repeated assessments three times with a gap of at least 24h between trials. Observers separately assessed UHs under four illumination conditions simulating illuminants D65, A, F2 and F11. An apparent hue shift (statistically significant for UR) was noted for UH selections at 5.7° field of view compared to those at 1.4°. Observers' overall variability was found to be higher for UH stimuli selections at the larger field of view. Intra-observer variability was found to be approximately 18.7% of inter-observer variability in selection of samples for both sample sizes. The highest intra-observer variability was under simulated illuminant D65, followed by A, F11, and F2. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Electronic structure and core-level spectra of light actinide dioxides in the dynamical mean-field theory

    Czech Academy of Sciences Publication Activity Database

    Kolorenč, Jindřich; Shick, Alexander; Lichtenstein, A.I.

    2015-01-01

    Roč. 92, č. 8 (2015), "085125-1"-"085125-10" ISSN 1098-0121 R&D Projects: GA ČR GC15-05872J Institutional support: RVO:68378271 Keywords : electronic-structure calculations * dynamical mean-field theory * Mott insulators * actinides * oxides * photoemission Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

  18. Regulatory Guide 1.131: Qualification tests of electric cables, field splices, and connections for light-water-cooled nuclear power plants

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Criterion III, ''Design Control,'' of Appendix B, ''Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plant,'' to 10 CFR Part 50, ''Licensing of Production and Utilization Facilities,'' requires that, where a test program is used to verify the adequacy of a specific design feature, it include suitable qualification testing of a prototype unit under the most adverse design conditions. This regulatory guide describes a method acceptable to the NRC staff for complying with the Commission's regulations with regard to qualification testing of electric cables, field splices, and connections for service in light-water-cooled nuclear power plants to ensure that the cables, field splices, and connections can perform their safety-related functions. The fire test provisions of this guide do not apply to qualification for an installed configuration

  19. [Occupational exposure of welders to ultraviolet and "blue light" radiation emitted during TIG and MMA welding based on field measurements].

    Science.gov (United States)

    Wolska, Agnieszka

    2013-01-01

    The aim of the study was to present the results of welders' occupational exposure to "blue light" and UV radiation carried out at industrial workstations during TIG and MMA welding. Measurements were performed at 13 workstations (TIG welding: 6; MMA welding: 7), at which different welding parameters and materials were used. The radiation level was measured using a wide-range radiometer and a set of detectors, whose spectral responses were adequately fit to particular hazard under study. The measurement points corresponded with the location of eye and hand. The highest values of eye irradiance were found for aluminum TIG welding. Effective irradiance of actinic UV was within the range E(s) = 7.79-37.6 W/m2; UVA total irradiance, E(UVA) = 18-53.1 W/m2 and effective blue-light irradiance E(B) = 35-67 W/m2. The maximum allowance time ranged from 1.7 to 75 s, which means that in some cases even unintentional very short eye exposure can exceed MPE. The influence of welded material and the type of electrode coating on the measured radiation level were evidenced. The exceeded value of MPE for photochemical hazard arising for the eyes and skin was found at all measured workstations. Welders should use appropriately the eye and face protective equipment and avoid direct staring at welding arc when starting an arc-welding operation. Besides, the lack of head and neck skin protection can induce acute and chronic harmful health effects. Therefore, an appropriate wear of personal protective equipment is essential for welders' health.

  20. Occupational exposure of welders to ultraviolet and "blue light" radiation emitted during TIG and MMA welding based on field measuremants

    Directory of Open Access Journals (Sweden)

    Agnieszka Wolska

    2013-02-01

    Full Text Available Background: The aim of the study was to present the results of welders' occupational exposure to "blue light" and UV radiation carried out at industrial workstations during TIG and MMA welding. Materials and methods: Measurements were performed at 13 workstations (TIG welding: 6; MMA welding: 7, at which different welding parameters and materials were used. The radiation level was measured using a wide-range radiometer and a set of detectors, whose spectral responses were adequately fit to particular hazard under study. The measurement points corresponded with the location of eye and hand. Results: The highest values of eye irradiance were found for aluminum TIG welding. Effective irradiance of actinic UV was within the range Es = 7.79-37.6 W/m2; UVA total irradiance, EUVA = 18-53.1 W/m2 and effective blue-light irradiance EB = 35-67 W/m2. The maximum allowance time ranged from 1.7 to 75 s, which means that in some cases even unintentional very short eye exposure can exceed MPE. Conclusions: The influence of welded material and the type of electrode coating on the measured radiation level were evidenced. The exceeded value of MPE for photochemical hazard arising for the eyes and skin was found at all measured workstations. Welders should use appropriately the eye and face protective equipment and avoid direct staring at welding arc when starting an arcwelding operation. Besides, the lack of head and neck skin protection can induce acute and chronic harmful health effects. Therefore, an appropriate wear of personal protective equipment is essential for welders' health. Med Pr 2013;64(1:69–82

  1. A neural network to improve dim-light vision? Dendritic fields of first-order interneurons in the nocturnal bee Megalopta genalis.

    Science.gov (United States)

    Greiner, Birgit; Ribi, Willi A; Warrant, Eric J

    2005-11-01

    Using the combined Golgi-electron microscopy technique, we have determined the three-dimensional dendritic fields of the short visual fibres (svf 1-3) and first-order interneurons or L-fibres (L1-4) within the first optic ganglion (lamina) of the nocturnal bee Megalopta genalis. Serial cross sections have revealed that the svf type 2 branches into one adjacent neural unit (cartridge) in layer A, the most distal of the three lamina layers A, B and C. All L-fibres, except L1-a, exhibit wide lateral branching into several neighbouring cartridges. L1-b shows a dendritic field of seven cartridges in layers A and C, dendrites of L2 target 13 cartridges in layer A, L3 branches over a total of 12 cartridges in layer A and three in layer C and L4 has the largest dendritic field size of 18 cartridges in layer C. The number of cartridges reached by the respective L-fibres is distinctly greater in the nocturnal bee than in the worker honeybee and is larger than could be estimated from our previous Golgi-light microscopy study. The extreme dorso-ventrally oriented dendritic field of L4 in M. genalis may, in addition to its potential role in spatial summation, be involved in edge detection. Thus, we have shown that the amount of lateral spreading present in the lamina provides the anatomical basis for the required spatial summation. Theoretical and future physiological work should further elucidate the roles that this lateral spreading plays to improve dim-light vision in nocturnal insects.

  2. Relativistic dynamics of an electron in a pulse of laser light with propagation along of an external magnetic field

    International Nuclear Information System (INIS)

    Gomez, F.; Ondarza, R.

    2003-01-01

    The exact solution for the movement of a charged particle in the interaction of an electromagnetic pulse elliptically polarized spreading along a static and homogeneous magnetic field is obtained starting from the equation of force. The solution method allows to solve, in terms of the phase, the trajectory of an accelerated particle by a pulse of arbitrary width and modulated by an encircling in Gaussian form. The reported solutions in this work have diverse applications in the laser-plasma interaction physics. (Author)

  3. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    International Nuclear Information System (INIS)

    Meyer, Patricia Froes; Costa, Iris do Ceu Clara; Brandao-Neto, Jose; Medeiros, Aldo da Cunha; Bonelli, Ludmila

    2007-01-01

    Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co) are labeled with technetium-99m ( 99m Tc) are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with 99m Tc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with 99m Tc was performed. Blood not exposed to the physical agents was used(controls). Data showed that the exposure to the different studied sources did not alter significantly (p>0.05) the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with 99m Tc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co. (author)

  4. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Patricia Froes; Costa, Iris do Ceu Clara; Brandao-Neto, Jose; Medeiros, Aldo da Cunha [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-graduacao em Ciencias da Saude; Santos-Filho, Sebastiao David; Adenilson de Souza da Fonseca; Bernardo-Filho, Mario [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Lab. de Radiofarmacia Experimental; Ariel Ronzio, Oscar [Universidad de Buenos Aires (Argentina); Bonelli, Ludmila [Universidade Salgado de Oliveira, Belo Horizonte, MG (Brazil)

    2007-09-15

    Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co) are labeled with technetium-99m ({sup 99m}Tc) are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with {sup 99m}Tc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with {sup 99m}Tc was performed. Blood not exposed to the physical agents was used(controls). Data showed that the exposure to the different studied sources did not alter significantly (p>0.05) the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with {sup 99m}Tc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co. (author)

  5. Experimental study on the 4H-SiC-based VDMOSFETs with lightly doped P-well field-limiting rings termination

    Science.gov (United States)

    He, Yan Jing; Lv, Hong Liang; Tang, Xiao Yan; Song, Qing Wen; Zhang, Yi Meng; Han, Chao; Zhang, Yi Men; Zhang, Yu Ming

    2017-03-01

    A lightly doped P-well field-limiting rings (FLRs) termination on 4H-SiC vertical double-implanted metal-oxide-semiconductor field-effect transistors (VDMOSFETs) has been investigated. Based on the simulation, the proposed termination applied to 4H-SiC VDMOSFET could achieve an almost same breakdown voltage (BV) and have the advantage of lower ion-implantation damage comparing with P+ FLRs termination. Meanwhile, this kind of termination also reduces the difficulty and consumption of fabrication process. 4H-SiC VDMOSFETs with lightly doped P-well (FLRs) termination have been fabricated on 10 μm thick epi-layer with nitrogen doping concentration of 6.2 × 1015 cm-3. The maximum breakdown voltage of the 4H-SiC VDMOSFETs has achieved as high as 1610 V at a current of 15 μA, which is very close to the simulated result of 1643 V and about 90% of the plane parallel breakdown voltage of 1780 V. It is considered that P-well FLRs termination is an effective, robust and process-tolerant termination structure suitable for 4H-SiC VDMOSFET.

  6. Improvement in the performance of graphene nanoribbon p-i-n tunneling field effect transistors by applying lightly doped profile on drain region

    Science.gov (United States)

    Naderi, Ali

    2017-12-01

    In this paper, an efficient structure with lightly doped drain region is proposed for p-i-n graphene nanoribbon field effect transistors (LD-PIN-GNRFET). Self-consistent solution of Poisson and Schrödinger equation within Nonequilibrium Green’s function (NEGF) formalism has been employed to simulate the quantum transport of the devices. In proposed structure, source region is doped by constant doping density, channel is an intrinsic GNR, and drain region contains two parts with lightly and heavily doped doping distributions. The important challenge in tunneling devices is obtaining higher current ratio. Our simulations demonstrate that LD-PIN-GNRFET is a steep slope device which not only reduces the leakage current and current ratio but also enhances delay, power delay product, and cutoff frequency in comparison with conventional PIN GNRFETs with uniform distribution of impurity and with linear doping profile in drain region. Also, the device is able to operate in higher drain-source voltages due to the effectively reduced electric field at drain side. Briefly, the proposed structure can be considered as a more reliable device for low standby-power logic applications operating at higher voltages and upper cutoff frequencies.

  7. Light scattering reviews 8 radiative transfer and light scattering

    CERN Document Server

    Kokhanovsky, Alexander A

    2013-01-01

    Light scattering review (vol 8) is aimed at the presentation of recent advances in radiative transfer and light scattering optics. The topics to be covered include: scattering of light by irregularly shaped particles suspended in atmosphere (dust, ice crystals), light scattering by particles much larger as compared the wavelength of incident radiation, atmospheric radiative forcing, astrophysical radiative transfer, radiative transfer and optical imaging in biological media, radiative transfer of polarized light, numerical aspects of radiative transfer.

  8. Hybrid active layers from a conjugated polymer and inorganic nanoparticles for organic light emitting devices with emission colour tuned by electric field

    Energy Technology Data Exchange (ETDEWEB)

    Aleshin, Andrey N; Alexandrova, Elena L; Shcherbakov, Igor P [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 26, Polytechnicheskaya Str., St Petersburg 194021 (Russian Federation)], E-mail: aleshin@transport.ioffe.ru

    2009-05-21

    We report on the investigation of the electrical and optical properties of hybrid active layers for organic devices consisting of a conjugated polymer MEH-PPV mixed with ZnO and Si nanoparticles. The effect of an electric field on the photoluminescence (PL) from a MEH-PPV : ZnO composite film is studied. We have found that in the absence of an electric field PL emission from the MEH-PPV : ZnO composites have two main maxima in the blue-red regions. Three additional minor PL maxima attributed to the exciplex states were found at {approx}420-480 nm. Application of a voltage bias to planar electrodes significantly suppresses the blue emission. Generation of excited states in the MEH-PPV : ZnO structures implies the presence of several radiative recombination mechanisms with the formation of polymer-nanoparticle complexes including exciplex states and charge transfer between the polymer and nanoparticles that can be controlled by an electric field. This effect provides the possibility to tune by an electric field the emission colour of organic light emitting diodes by combining an efficient emission from both organic/inorganic materials involved.

  9. Hybrid active layers from a conjugated polymer and inorganic nanoparticles for organic light emitting devices with emission colour tuned by electric field

    International Nuclear Information System (INIS)

    Aleshin, Andrey N; Alexandrova, Elena L; Shcherbakov, Igor P

    2009-01-01

    We report on the investigation of the electrical and optical properties of hybrid active layers for organic devices consisting of a conjugated polymer MEH-PPV mixed with ZnO and Si nanoparticles. The effect of an electric field on the photoluminescence (PL) from a MEH-PPV : ZnO composite film is studied. We have found that in the absence of an electric field PL emission from the MEH-PPV : ZnO composites have two main maxima in the blue-red regions. Three additional minor PL maxima attributed to the exciplex states were found at ∼420-480 nm. Application of a voltage bias to planar electrodes significantly suppresses the blue emission. Generation of excited states in the MEH-PPV : ZnO structures implies the presence of several radiative recombination mechanisms with the formation of polymer-nanoparticle complexes including exciplex states and charge transfer between the polymer and nanoparticles that can be controlled by an electric field. This effect provides the possibility to tune by an electric field the emission colour of organic light emitting diodes by combining an efficient emission from both organic/inorganic materials involved.

  10. A non-local-thermodynamic equilibrium formulation of the transport equation for polarized light in the presence of weak magnetic fields. Doctoral thesis

    International Nuclear Information System (INIS)

    McNamara, D.J.

    1977-01-01

    The present work is motivated by the desire to better understand solar magnetism. Just as stellar astrophysics and radiative transfer have been coupled in the history of research in physics, so too has the study of radiative transfer of polarized light in magnetic fields and solar magnetism been a history of mutual growth. The Stokes parameters characterize the state of polarization of a beam of radiation. The author considers the changes in polarization, and therefore in the Stokes parameters, due to the transport of a beam through an optically thick medium in a weak magnetic field. The transport equation is derived from a general density matrix equation of motion. This allows the possibility of interference effects arising from the mixing of atomic sublevels in a weak magnetic field to be taken into account. The statistical equilibrium equations are similarly derived. Finally, the coupled system of equations is presented, and the order of magnitude of the interference effects, shown. Collisional effects are not considered. The magnitude of the interference effects in magnetic field measurements of the sun may be evaluated

  11. Light Water Reactor Sustainability Program: Computer-based procedure for field activities: results from three evaluations at nuclear power plants

    International Nuclear Information System (INIS)

    2014-01-01

    Nearly all activities that involve human interaction with the systems of a nuclear power plant are guided by procedures. The paper-based procedures (PBPs) currently used by industry have a demonstrated history of ensuring safety; however, improving procedure use could yield tremendous savings in increased efficiency and safety. One potential way to improve procedure-based activities is through the use of computer-based procedures (CBPs). Computer-based procedures provide the opportunity to incorporate context driven job aids, such as drawings, photos, just-in-time training, etc into CBP system. One obvious advantage of this capability is reducing the time spent tracking down the applicable documentation. Additionally, human performance tools can be integrated in the CBP system in such way that helps the worker focus on the task rather than the tools. Some tools can be completely incorporated into the CBP system, such as pre-job briefs, placekeeping, correct component verification, and peer checks. Other tools can be partly integrated in a fashion that reduces the time and labor required, such as concurrent and independent verification. Another benefit of CBPs compared to PBPs is dynamic procedure presentation. PBPs are static documents which limits the degree to which the information presented can be tailored to the task and conditions when the procedure is executed. The CBP system could be configured to display only the relevant steps based on operating mode, plant status, and the task at hand. A dynamic presentation of the procedure (also known as context-sensitive procedures) will guide the user down the path of relevant steps based on the current conditions. This feature will reduce the user's workload and inherently reduce the risk of incorrectly marking a step as not applicable and the risk of incorrectly performing a step that should be marked as not applicable. As part of the Department of Energy's (DOE) Light Water Reactors Sustainability Program

  12. Polysaccharide characterization by hollow-fiber flow field-flow fractionation with on-line multi-angle static light scattering and differential refractometry.

    Science.gov (United States)

    Pitkänen, Leena; Striegel, André M

    2015-02-06

    Accurate characterization of the molar mass and size of polysaccharides is an ongoing challenge, oftentimes due to architectural diversity but also to the broad molar mass (M) range over which a single polysaccharide can exist and to the ultra-high M of many polysaccharides. Because of the latter, many of these biomacromolecules experience on-column, flow-induced degradation during analysis by size-exclusion and, even, hydrodynamic chromatography (SEC and HDC, respectively). The necessity for gentler fractionation methods has, to date, been addressed employing asymmetric flow field-flow fractionation (AF4). Here, we introduce the coupling of hollow-fiber flow field-flow fractionation (HF5) to multi-angle static light scattering (MALS) and differential refractometry (DRI) detection for the analysis of polysaccharides. In HF5, less stresses are placed on the macromolecules during separation than in SEC or HDC, and HF5 can offer a higher sensitivity, with less propensity for system overloading and analyte aggregation, than generally found in AF4. The coupling to MALS and DRI affords the determination of absolute, calibration-curve-independent molar mass averages and dispersities. Results from the present HF5/MALS/DRI experiments with dextrans, pullulans, and larch arabinogalactan were augmented with hydrodynamic radius (RH) measurements from off-line quasi-elastic light scattering (QELS) and by RH distribution calculations and fractogram simulations obtained via a finite element analysis implementation of field-flow fractionation theory by commercially available software. As part of this study, we have investigated analyte recovery in HF5 and also possible reasons for discrepancies between calculated and simulated results vis-à-vis experimentally determined data. Published by Elsevier B.V.

  13. States of maximum polarization for a quantum light field and states of a maximum sensitivity in quantum interferometry

    International Nuclear Information System (INIS)

    Peřinová, Vlasta; Lukš, Antonín

    2015-01-01

    The SU(2) group is used in two different fields of quantum optics, the quantum polarization and quantum interferometry. Quantum degrees of polarization may be based on distances of a polarization state from the set of unpolarized states. The maximum polarization is achieved in the case where the state is pure and then the distribution of the photon-number sums is optimized. In quantum interferometry, the SU(2) intelligent states have also the property that the Fisher measure of information is equal to the inverse minimum detectable phase shift on the usual simplifying condition. Previously, the optimization of the Fisher information under a constraint was studied. Now, in the framework of constraint optimization, states similar to the SU(2) intelligent states are treated. (paper)

  14. Next Generation Light Robotics

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    Light Robotics is a new field of research where ingredients from photonics, nanotechnology and biotechnology are put together in new ways to realize light-driven robotics at the smallest scales to solve major challenges primarily within the nanobio-domain but not limited hereto. Exploring the full...... potential of this new ‘drone-like’ light-printed, light-driven, light-actuated micro- and nano-robotics in challenging geometries requires a versatile and real-time reconfigurable light addressing that can dynamically track a plurality of tiny tools in 3D to ensure real-time continuous light...

  15. Low-field microwave absorption and magnetoresistance in iron nanostructures grown by electrodeposition on n-type lightly doped silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Felix, J.F. [Universidade Federal de Viçosa-UFV, Departamento de Física, 36570-900 Viçosa, MG (Brazil); Universidade de Brasília-UnB, Instituto de Física, Núcleo de Física Aplicada, 70910-900 Brasília, DF (Brazil); Figueiredo, L.C. [Universidade de Brasília-UnB, Instituto de Física, Núcleo de Física Aplicada, 70910-900 Brasília, DF (Brazil); Mendes, J.B.S. [Universidade Federal de Viçosa-UFV, Departamento de Física, 36570-900 Viçosa, MG (Brazil); Morais, P.C. [Universidade de Brasília-UnB, Instituto de Física, Núcleo de Física Aplicada, 70910-900 Brasília, DF (Brazil); Huazhong University of Science and Technology, School of Automation, 430074 Wuhan (China); Araujo, C.I.L. de., E-mail: dearaujo@ufv.br [Universidade de Brasília-UnB, Instituto de Física, Núcleo de Física Aplicada, 70910-900 Brasília, DF (Brazil)

    2015-12-01

    In this study we investigate magnetic properties, surface morphology and crystal structure in iron nanoclusters electrodeposited on lightly doped (100) n-type silicon substrates. Our goal is to investigate the spin injection and detection in the Fe/Si lateral structures. The samples obtained under electric percolation were characterized by magnetoresistive and magnetic resonance measurements with cycling the sweeping applied field in order to understand the spin dynamics in the as-produced samples. The observed hysteresis in the magnetic resonance spectra, plus the presence of a broad peak in the non-saturated regime confirming the low field microwave absorption (LFMA), were correlated to the peaks and slopes found in the magnetoresistance curves. The results suggest long range spin injection and detection in low resistive silicon and the magnetic resonance technique is herein introduced as a promising tool for analysis of electric contactless magnetoresistive samples. - Highlights: • Electrodeposition of Fe nanostructures on high resistive silicon substrates. • Spin polarized current among clusters through Si suggested by isotropic magnetoresistance. • Low field microwave absorption arising from the sample shape anisotropy. • Contactless magnetoresistive device characterization by resonance measurements.

  16. Effective suppression of efficiency droop in GaN-based light-emitting diodes: role of significant reduction of carrier density and built-in field

    Science.gov (United States)

    Yoo, Yang-Seok; Na, Jong-Ho; Son, Sung Jin; Cho, Yong-Hoon

    2016-10-01

    A critical issue in GaN-based high power light-emitting diodes (LEDs) is how to suppress the efficiency droop problem occurred at high current injection while improving overall quantum efficiency, especially in conventional c-plane InGaN/GaN quantum well (QW), without using complicated bandgap engineering or unconventional materials and structures. Although increasing thickness of each QW may decrease carrier density in QWs, formation of additional strain and defects as well as increased built-in field effect due to enlarged QW thickness are unavoidable. Here, we propose a facile and effective method for not only reducing efficiency droop but also improving quantum efficiency by utilizing c-plane InGaN/GaN QWs having thinner barriers and increased QW number while keeping the same single well thickness and total active layer thickness. As the barrier thickness decreases and the QW number increases, both internal electric field and carrier density within QWs are simultaneously reduced without degradation of material quality. Furthermore, we found overall improved efficiency and reduced efficiency droop, which was attributed to the decrease of the built-in field and to less influence by non-radiative recombination processes at high carrier density. This simple and effective approach can be extended further for high power ultraviolet, green, and red LEDs.

  17. The effects of extreme low frequency pulsed electromagnetic field on bone mineral density and incidence of fractures in patients with end - stage renal disease on dialysis - three year follow up study

    Directory of Open Access Journals (Sweden)

    Rakočević-Hrnjak Aleksandra

    2018-01-01

    Full Text Available Background/Aim. A variety of physical therapy options has been developed for the treatment of musculoskeletal disorders including those characterized with low bone mineral density (BMD. Extreme low frequency pulsed electromagnetic field (ELF-PEMF can accelerate bone formation. Patients with end stage of renal disease (ESRD are predisposed to high incidence of fractures due to bone disorder with multifactorial pathogenesis. Vitamin D, calcium supplements, antiresorptive and anabolic drugs in those patients have changed pharmacodynamics and pharmacokinetics and have minimal or limited effects. The aim of this study was to assess the effectiveness of long-term ELF-PEMF therapy applied in concordance with physical exercise on bone mass, incidence of new bone fractures and parathyroid hormone concentrations in ESRD patients on dialysis. Methods. In this 3-year prospective clinical trial, 151 patients with ESRD on dialysis program were subjected to treatment with ELF-PEMF (18 Hz, 2 mT applied during 40 min after 10 consecutive dialysis procedures, 4 times through one year (120 treatments in total during three years together with kinesitherapy (study group or only with kinesitherapy (control group on the voluntary basis. Results. Total of 124 patients have completed the study. In the study group (n = 54, regardless of sex, significant improvements of BMD, T-score and Z-score on both lumbar spine and femoral neck were achieved after 3-year treatment with ELF-PEMF. In the control group (n = 70, significant decreases of BMD, T-score and Z-score as well as the higher incidence of new bone fractures were recorded. Conclusion. ELF-PEMF could be a convenient and safe non-pharmacological therapeutic strategy for fracture prevention in nephrology practices.

  18. Light intensity modulation by coccoliths of Emiliania huxleyi as a micro-photo-regulator

    Science.gov (United States)

    Mizukawa, Yuri; Miyashita, Yuito; Satoh, Manami; Shiraiwa, Yoshihiro; Iwasaka, Masakazu

    2015-09-01

    In this study, we present experimental evidence showing that coccoliths have light-scattering anisotropy that contributes to a possible control of solar light exposure in the ocean. Changing the angle between the incident light and an applied magnetic field causes differences in the light-scattering intensities of a suspension of coccoliths isolated from Emiliania huxleyi. The magnetic field effect is induced by the diamagnetic torque force directing the coccolith radial plane perpendicular to the applied magnetic fields at 400 to 500 mT. The developed technique reveals the light-scattering anisotropies in the 3-μm-diameter floating coccoliths by orienting themselves in response to the magnetic fields. The detached coccolith scatters radially the light incident to its radial plane. The experimental results on magnetically oriented coccoliths show that an individual coccolith has a specific direction of light scattering, although the possible physiological effect of the coccolith remains for further study, focusing on the light-scattering anisotropies of coccoliths on living cells.

  19. Combining asymmetrical flow field-flow fractionation with light-scattering and inductively coupled plasma mass spectrometric detection for characterization of nanoclay used in biopolymer nanocomposites

    DEFF Research Database (Denmark)

    Schmidt, Bjørn; Petersen, Jens Højslev; Koch, C. Bender

    2009-01-01

    mechanical and barrier properties and be more suitable for a wider range of food-packaging applications. Natural or synthetic clay nanofillers are being investigated for this purpose in a project called NanoPack funded by the Danish Strategic Research Council. In order to detect and characterize the size...... of clay nanoparticulates, an analytical system combining asymmetrical flow field-flow fractionation (AF4) with multi-angle light-scattering detection (MALS) and inductively coupled plasma mass spectrometry (ICP-MS) is presented. In a migration study, we tested a biopolymer nanocomposite consisting...... of polylactide (PLA) with 5% Cloisite®30B (a derivatized montmorillonite clay) as a filler. Based on AF4-MALS analyses, we found that particles ranging from 50 to 800 nm in radius indeed migrated into the 95% ethanol used as a food simulant. The full hyphenated AF4-MALS-ICP-MS system showed, however, that none...

  20. The effect of electric field strength on electroplex emission at the interface of NPB/PBD organic light-emitting diodes

    Science.gov (United States)

    Zhao, De-Wei; Xu, Zheng; Zhang, Fu-Jun; Song, Shu-Fang; Zhao, Su-Ling; Wang, Yong; Yuan, Guang-Cai; Zhang, Yan-Fei; Xu, Hong-Hua

    2007-02-01

    Organic light-emitting diode (OLED) based on two kinds of blue emission materials N, N'-bis(1-naphthyl)- N, N'-diphenyl-l,l'-diphenyl-4,4'-diamine (NPB) and 2-(4-biphenylyl)-5(4- tert-butyl-phenyl)-1,3,4-oxadiazole (PBD) was fabricated. There is only one emission peak in photoluminescence (PL) spectrum which originates from NPB exciton emission. And the electroluminescence (EL) emission peaks have an apparent red-shift with the increase of driving voltage. The red-shift emission from exciplex emission could be ruled out. Thus, by the method of Gaussian fitting it should be ascribed to the overlap of exciton emission and electroplex emission which occurs at the interface between NPB and PBD. The formation of the electroplex emission under high electric field is analyzed.

  1. State of the Art, Trends and Future of Bluetooth Low Energy, Near Field Communication and Visible Light Communication in the Development of Smart Cities

    Science.gov (United States)

    Cerruela García, Gonzalo; Luque Ruiz, Irene; Gómez-Nieto, Miguel Ángel

    2016-01-01

    The current social impact of new technologies has produced major changes in all areas of society, creating the concept of a smart city supported by an electronic infrastructure, telecommunications and information technology. This paper presents a review of Bluetooth Low Energy (BLE), Near Field Communication (NFC) and Visible Light Communication (VLC) and their use and influence within different areas of the development of the smart city. The document also presents a review of Big Data Solutions for the management of information and the extraction of knowledge in an environment where things are connected by an “Internet of Things” (IoT) network. Lastly, we present how these technologies can be combined together to benefit the development of the smart city. PMID:27886087

  2. State of the Art, Trends and Future of Bluetooth Low Energy, Near Field Communication and Visible Light Communication in the Development of Smart Cities.

    Science.gov (United States)

    Cerruela García, Gonzalo; Luque Ruiz, Irene; Gómez-Nieto, Miguel Ángel

    2016-11-23

    The current social impact of new technologies has produced major changes in all areas of society, creating the concept of a smart city supported by an electronic infrastructure, telecommunications and information technology. This paper presents a review of Bluetooth Low Energy (BLE), Near Field Communication (NFC) and Visible Light Communication (VLC) and their use and influence within different areas of the development of the smart city. The document also presents a review of Big Data Solutions for the management of information and the extraction of knowledge in an environment where things are connected by an "Internet of Things" (IoT) network. Lastly, we present how these technologies can be combined together to benefit the development of the smart city.

  3. Energy transfer between surface-immobilized light-harvesting chlorophyll a/b complex (LHCII) studied by surface plasmon field-enhanced fluorescence spectroscopy (SPFS).

    Science.gov (United States)

    Lauterbach, Rolf; Liu, Jing; Knoll, Wolfgang; Paulsen, Harald

    2010-11-16

    The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCII potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCII to be immobilized on a solid surface. In a previous study we showed the immobilization of recombinant LHCII on functionalized gold surfaces via a 6-histidine tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Förster energy transfer between immobilized LHCII on a functionalized surface have been analyzed by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCII.

  4. Portable, universal, and visual ion sensing platform based on the light emitting diode-based self-referencing-ion selective field-effect transistor.

    Science.gov (United States)

    Zhang, Xiaowei; Han, Yanchao; Li, Jing; Zhang, Libing; Jia, Xiaofang; Wang, Erkang

    2014-02-04

    In this work, a novel and universal ion sensing platform was presented, which enables the visual detection of various ions with high sensitivity and selectivity. Coaxial potential signals (millivolt-scale) of the sample from the self-referencing (SR) ion selective chip can be transferred into the ad620-based amplifier with an output of volt-scale potentials. The amplified voltage is high enough to drive a light emitting diode (LED), which can be used as an amplifier and indicator to report the sample information. With this double amplification device (light emitting diode-based self-referencing-ion selective field-effect transistor, LED-SR-ISFET), a tiny change of the sample concentration can be observed with a distinguishable variation of LED brightness by visual inspection. This LED-based luminescent platform provided a facile, low-cost, and rapid sensing strategy without the need of additional expensive chemiluminescence reagent and instruments. Moreover, the SR mode also endows this device excellent stability and reliability. With this innovative design, sensitive determination of K(+), H(+), and Cl(-) by the naked eye was achieved. It should also be noticed that this sensing strategy can easily be extended to other ions (or molecules) by simply integrating the corresponding ion (or molecule) selective electrode.

  5. Influence of the substrate platform on the opto-electronic properties of multi-layer organic light-emitting field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Generali, Gianluca; Capelli, Raffaella; Toffanin, Stefano; Muccini, Michele [Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna (Italy); Dinelli, Franco, E-mail: g.generali@bo.ismn.cnr.it, E-mail: m.muccini@bo.ismn.cnr.it [Consiglio Nazionale delle Ricerche (CNR), INO U.O.S. ' A. Gozzini' Area della Ricerca di Pisa - S. Cataldo, via Moruzzi 1, I-56124 Pisa (Italy)

    2011-06-08

    In this paper, we present a study of the effects of the influence of the substrate platform on the properties of a three-layer vertical hetero-junction made of thin films of {alpha}, {omega}-diperfluorohexyl-4T (DHF4T), a blend of tris(8-hydroxyquinoline)aluminium (Alq3) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) and {alpha}, {omega}-dihexyl-quaterthiophene (DH4T). The hetero-junction represents the active component of an organic light-emitting transistor (OLET). The substrate platforms investigated in this study are glass/indium-tin-oxide/poly(methyl-methacrylate) (PMMA) and Si{sup ++}/silicon oxide (SiO{sub 2})/PMMA. The first platform is almost completely transparent to light and therefore is very promising for use in OLET applications. The second one has been chosen for comparison as it employs standard microelectronic materials, i.e. Si{sup ++}/SiO{sub 2}. We show how different gate materials and structure can affect the relevant field-effect electrical characteristics, such as the charge mobility and threshold voltage. By means of an atomic force microscopy analysis, a systematic study has been made in order to correlate the morphology of the active layers with the electrical properties of the devices.

  6. Harvesting Triplet Excitons with Exciplex Thermally Activated Delayed Fluorescence Emitters toward High Performance Heterostructured Organic Light-Emitting Field Effect Transistors.

    Science.gov (United States)

    Song, Li; Hu, Yongsheng; Liu, Zheqin; Lv, Ying; Guo, Xiaoyang; Liu, Xingyuan

    2017-01-25

    The utilization of triplet excitons plays a key role in obtaining high emission efficiency for organic electroluminescent devices. However, to date, only phosphorescent materials have been implemented to harvest the triplet excitons in the organic light-emitting field effect transistors (OLEFETs). In this work, we report the first incorporation of exciplex thermally activated delayed fluorescence (TADF) emitters in heterostructured OLEFETs to harvest the triplet excitons. By developing a new kind of exciplex TADF emitter constituted by m-MTDATA (4,4',4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine) as the donor and OXD-7 (1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazo-5-yl]benzene) as the acceptor, an exciton utilization efficiency of 74.3% for the devices was achieved. It is found that the injection barrier between hole transport layer and emission layer as well as the ratio between donor and acceptor would influence the external quantum efficiency (EQE) significantly. Devices with a maximum EQE of 3.76% which is far exceeding the reported results for devices with conventional fluorescent emitters were successfully demonstrated. Moreover, the EQE at high brightness even outperformed the result for organic light-emitting diode based on the same emitter. Our results demonstrate that the exciplex TADF emitters can be promising candidates to develop OLEFETs with high performance.

  7. 1. Safety in operation: The challenges and the fields of action. 2. Incident and accident management in PWR plants ''The French approach''

    International Nuclear Information System (INIS)

    Debes, M.

    1992-01-01

    The French standardization pressurized water reactor facilities currently consist of 51 standardized units, 34 of 900 MW and 17 of 1300 MW. For EDF, safety and quality in operation constitute a unique challenge: An economic challenge: the nuclear facilities account for 75% of the power generated in France and ensure the competitiveness of its price, both for domestic consumers and on the international markets, an environmental challenge: both to limit actual and potential radioactive releases associated with operation of the nuclear facilities, and to avoid releases of combustion gases associated with the use of fossil fuels, a public relations challenge: to improve the image and the confidence of the public associated with nuclear generation. Safety in operation dependence primarily on the quality of the design and construction of the nuclear units. But it also depends on technical, human and organizational factors specific to the operation of the units, which play an essential role in maintaining and increasing operating safety. After a brief review of the safety results of the facilities and of the main themes which contribute to safety in operation, a description is given of the principal fields involved and of the main current orientations

  8. Influence of a weak field of pulsed DC electricity on the behavior and incidence of injury in adult Steelhead and Pacific Lamprey

    Science.gov (United States)

    Mesa, Matthew G.; Copeland, Elizabeth S.

    2009-01-01

    Predation by pinnipeds, such as California sea lions Zalophus californianus, Pacific harbor seals Phoca vitulina, and Stellar sea lions Eumetopias jubatus on adult Pacific salmon Oncorhynchus spp in the lower Columbia River has become a serious concern for fishery managers trying to conserve and restore runs of threatened and endangered fish. As a result, Smith-Root, Incorporated (SRI; Vancouver, Washington), manufacturers of electrofishing and closely-related equipment, proposed a project to evaluate the potential of an electrical barrier to deter marine mammals and reduce the amount of predation on adult salmonids (SRI 2007). The objectives of their work were to develop, deploy, and evaluate a passive, integrated sonar and electric barrier that would selectively inhibit the upstream movements of marine mammals and reduce predation, but would not injure pinnipeds or impact anadromous fish migrations. However, before such a device could be deployed in the field, concerns by regional fishery managers about the potential effects of such a device on the migratory behavior of Pacific salmon, steelhead O. mykiss, Pacific lampreys Entoshpenus tridentata, and white sturgeon Acipenser transmontanus, needed to be addressed. In this report, we describe the results of laboratory research designed to evaluate the effects of prototype electric barriers on adult steelhead and Pacific lampreys.

  9. Regional comparison of cancer incidence

    International Nuclear Information System (INIS)

    Obralic, N.; Gavrankapetanovic, F.; Dizdarevic, Z.; Duric, O.; Sisic, F.; Selak, I.; Balta, S.; Nakas, B.

    2004-01-01

    Background. Due to specific war and post-war situation in Balkan region, differences in the number, type, development, biological course, treatment of malignant tumours and its outcome are possible. In order to perceive the situation realistically, it is necessary to gather continuously exact data about malignant tumours and compare them with the data from other European and world countries.The aim of the study was to collect and analyse the data on cancer incidence in the region of Sarajevo city, which represents a symbol of difficult times in the recent past, and to compare it to the incidence in the neighbouring countries. Patients and methods. Data on all newly diagnosed cancer cases, permanent residents of Sarajevo Canton, in the years 1999 and 2000 were collected. Crude incidence rate has been calculated according to the years observed, gender and localizations of the disease The data were compared to the cancer registries of Slovenia and Croatia and were observed in the light of specific local situation. Results. The crude cancer incidence of all sites but skin was the highest in both years and by both genders in Croatia. The incidence of the most common tumours (lung and breast cancer) was similar in all three countries. The differences in the incidence between both genders in the Sarajevo canton were registered in laryngeal and urinary bladder cancer, as well as in bone and cartilage sarcoma. Cervical cancer had extremely high incidence and was high up on the incidence list in the Sarajevo canton, which correlates with the data in developing countries. The incidence of other tumours in the post-war period is reaching expected numbers. Conclusions. It is difficult to identify whether the war and post-war stress, irregular and insufficient nutrition during and after the siege of the city of Sarajevo or some other factor influenced the cancer incidence among exposed population. The prevalence of smoking in the whole region is extremely high, in Bosnia and

  10. Light scattering by surface phonons in crystals

    International Nuclear Information System (INIS)

    Albuquerque, E.L. de

    1981-01-01

    A theory of inelastic light scattering by surface acoustic phonons in homogeneous crystals is presented. The Green functions are determined by the use of a classical linear response method and used to evaluate the Brillouin cross section. The acoustic modes are found from solutions to the acoustical-wave equation and boundary conditions appropriated. Two light-scattering mechanisms, namely the surface corrugation and bulk elasto-optic effect are analyzed by deriving optical fields which satisfy both the acousto-optically driven wave equation and the electromagnetic boundary conditions. No restrictions are imposed concerning the angle of incidence of the light. Some representative computed Brillouin lineshapes are also presented and their features discussed. (Author) [pt

  11. Light scattering by surface phonons in crystals

    International Nuclear Information System (INIS)

    Albuquerque, D.L.

    1980-01-01

    Theory of inelastic light scattering by surface acoustic phonons homogeneous crystals is presented. The Green functions are determined by the use of a classical linear response method and used to evaluate the Brillouin cross section. The acoustic modes are found from solutions to the acoustical-wave equation and boundary conditions appropriated. Two light-scattering mechanisms, amely the surface corrugation and bulk elasto-optic effect are analyzed by deriving optical fields which satisfy both the acousto-optically driven wave equation and the electromagnetic boundary conditions. No restrictions are imposed concerning the angle of incidence of the light. Some representative computed Brillouin ineshapes are also presented and their features discussed. (author) [pt

  12. Evaluation of the conditions of operation of X-ray equipment as regards the coincidence between light field, radiation field and the central ray alignment in radiology services of the Recife, Brazil

    International Nuclear Information System (INIS)

    Oliveira, Claudia F.M.; Silva, Iran J.O.; Lopes Filho, Ferdinand J.; Morais, Carolinne S.; Junior, Claudio L.R.

    2014-01-01

    This paper aims at considering the need for constant evaluation of diagnostic radiology equipment and the fact that this issue be part of the radiology technologist's tasks, develop skills in radiology technologist through applying quality control tests, as regards the assessment of coincidence between the light field and the radiation field and the alignment of the radiation beam of medical X-ray equipment in radiology services in the city of Recife. For the tests, the procedures by national protocols of Quality Control Tests were adopted - QCT and the Medical Radiodiagnosis Manual. The instruments used to check the alignment of the central ray was an acrylic cylinder with steel balls of 0.8 mm diameter located in the upper and lower base separated by a distance of 15 cm, a chassis loaded with film, tape and level bubble. The results show that the tested devices are in good condition for diagnostic radiology, with regard to both the radiation field to be exposed as well as the image quality for a more accurate diagnosis, which guarantees the individual radiological protection

  13. Light pollution : working paper

    NARCIS (Netherlands)

    Lechner, Stefan; Arns, Marieke

    2013-01-01

    Light pollution is one of the fastest growing and most pervasive of environmental pollution (Chepesiuk, 2009). In the last couple of years, a lot of research has been done about the effects of light pollution. The interest in light pollution has been growing in many fields of science, extending from

  14. Architectural Physics: Lighting.

    Science.gov (United States)

    Hopkinson, R. G.

    The author coordinates the many diverse branches of knowledge which have dealt with the field of lighting--physiology, psychology, engineering, physics, and architectural design. Part I, "The Elements of Architectural Physics", discusses the physiological aspects of lighting, visual performance, lighting design, calculations and measurements of…

  15. Polarization Patterns of Transmitted Celestial Light under Wavy Water Surfaces

    Directory of Open Access Journals (Sweden)

    Guanhua Zhou

    2017-03-01

    Full Text Available This paper presents a model to describe the polarization patterns of celestial light, which includes sunlight and skylight, when refracted by wavy water surfaces. The polarization patterns and intensity distribution of refracted light through the wave water surface were calculated. The model was validated by underwater experimental measurements. The experimental and theoretical values agree well qualitatively. This work provides a quantitative description of the repolarization and transmittance of celestial light transmitted through wave water surfaces. The effects of wind speed and incident sources on the underwater refraction polarization patterns are discussed. Scattering skylight dominates the polarization patterns while direct solar light is the dominant source of the intensity of the underwater light field. Wind speed has an influence on disturbing the patterns under water.

  16. Ultraviolet light imaging technology and applications

    Science.gov (United States)

    Yokoi, Takane; Suzuki, Kenji; Oba, Koichiro

    1991-06-01

    Demands on the high-quality imaging in ultraviolet (UV) light region have been increasing recently, especially in fields such as forensic investigations, laser experiments, spent fuel identification, and so on. Important requirements on the UV imaging devices in such applications are high sensitivity, excellent solar blindness, and small image distortion, since the imaging of very weak UV images are usually carried out under natural sunlight or room illuminations and the image data have to be processed to produce useful two-dimensional quantitative data. A new photocathode has been developed to meet these requirements. It is specially made of RbTe on a sapphire window and its quantum efficiency is as high as 20% with the solar blindness of 10,000. The tube is specially designed to meet UV light optics and to minimize image distortion. It has an invertor type image intensifier tube structure and intensifies the incident UV light up to approximately 10,000 times. The distortion of the output image is suppressed less than 1.8%, because of a specially designed electron optic lens system. The device has shown excellent results in the observation of such objects as fingerprints and footprints in forensic investigations, the Cherenkov light produced by the spent fuels stored in a cooling water pool in the nuclear power station, and UV laser beam path in excimer laser experiments. Furthermore, many other applications of the UV light imaging will be expected in various fields such as semiconductors, cosmetics, and electrical power.

  17. Structural dynamics of phenylisothiocyanate in the light-absorbing excited states: Resonance Raman and complete active space self-consistent field calculation study

    International Nuclear Information System (INIS)

    Ouyang, Bing; Xue, Jia-Dan; Zheng, Xuming; Fang, Wei-Hai

    2014-01-01

    The excited state structural dynamics of phenyl isothiocyanate (PITC) after excitation to the light absorbing S 2 (A′), S 6 (A′), and S 7 (A′) excited states were studied by using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The UV absorption bands of PITC were assigned. The vibrational assignments were done on the basis of the Fourier transform (FT)-Raman and FT-infrared measurements, the density-functional theory computations, and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohexane, acetonitrile, and methanol solvents were, respectively, obtained at 299.1, 282.4, 266.0, 252.7, 228.7, 217.8, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PITC. The results indicated that the structural dynamics in the S 2 (A′), S 6 (A′), and S 7 (A′) excited states were very different. The conical intersection point CI(S 2 /S 1 ) were predicted to play important role in the low-lying excited state decay dynamics. Two major decay channels were predicted for PITC upon excitation to the S 2 (A′) state: the radiative S 2,min → S 0 transition and the nonradiative S 2 → S 1 internal conversion via CI(S 2 /S 1 ). The differences in the decay dynamics between methyl isothiocyanate and PITC in the first light absorbing excited state were discussed. The role of the intersystem crossing point ISC(S 1 /T 1 ) in the excited state decay dynamics of PITC is evaluated

  18. Aerosol and cloud properties derived from hyperspectral transmitted light in the southeast Atlantic sampled during field campaign deployments in 2016 and 2017

    Science.gov (United States)

    LeBlanc, S. E.; Redemann, J.; Flynn, C. J.; Segal-Rosenhaimer, M.; Kacenelenbogen, M. S.; Shinozuka, Y.; Pistone, K.; Karol, Y.; Schmidt, S.; Cochrane, S.; Chen, H.; Meyer, K.; Ferrare, R. A.; Burton, S. P.; Hostetler, C. A.; Hair, J. W.

    2017-12-01

    We present aerosol and cloud properties collected from airborne remote-sensing measurements in the southeast Atlantic during the recent NASA ObseRvations of CLouds above Aerosols and their intEractionS (ORACLES) field campaign. During the biomass burning seasons of September 2016 and August 2017, we sampled aerosol layers which overlaid marine stratocumulus clouds off the southwestern coast of Africa. We sampled these aerosol layers and the underlying clouds from the NASA P3 airborne platform with the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR). Aerosol optical depth (AOD), along with trace gas content in the atmospheric column (water vapor, NO2, and O3), is obtained from the attenuation in the sun's direct beam, measured at the altitude of the airborne platform. Using hyperspectral transmitted light measurements from 4STAR, in conjunction with hyperspectral hemispheric irradiance measurements from the Solar Spectral Flux Radiometers (SSFR), we also obtained aerosol intensive properties (asymmetry parameter, single scattering albedo), aerosol size distributions, cloud optical depth (COD), cloud particle effective radius, and cloud thermodynamic phase. Aerosol intensive properties are retrieved from measurements of angularly resolved skylight and flight level spectral albedo using the inversion used with measurements from AERONET (Aerosol Robotic Network) that has been modified for airborne use. The cloud properties are obtained from 4STAR measurements of scattered light below clouds. We show a favorable initial comparison of the above-cloud AOD measured by 4STAR to this same product retrieved from measurements by the MODIS instrument on board the TERRA and AQUA satellites. The layer AOD observed above clouds will also be compared to integrated aerosol extinction profile measurements from the High Spectral Resolution Lidar-2 (HSRL-2).

  19. Quantitative characterization of gold nanoparticles by field-flow fractionation coupled online with light scattering detection and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Schmidt, Bjørn; Loeschner, Katrin; Hadrup, Niels; Mortensen, Alicja; Sloth, Jens J; Koch, Christian Bender; Larsen, Erik H

    2011-04-01

    An analytical platform coupling asymmetric flow field-flow fractionation (AF(4)) with multiangle light scattering (MALS), dynamic light scattering (DLS), and inductively coupled plasma mass spectrometry (ICPMS) was established and used for separation and quantitative determination of size and mass concentration of nanoparticles (NPs) in aqueous suspension. Mixtures of three polystyrene (PS) NPs between 20 and 100 nm in diameter and mixtures of three gold (Au) NPs between 10 and 60 nm in diameter were separated by AF(4). The geometric diameters of the separated PS NPs and the hydrodynamic diameters of the Au and PS NPs were determined online by MALS and DLS, respectively. The three separated Au NPs were quantified by ICPMS and recovered at 50-95% of the injected masses, which ranged between approximately 8-80 ng of each nanoparticle size. Au NPs adhering to the membrane in the separation channel was found to be a major cause for incomplete recoveries. The lower limit of detection (LOD) ranged between 0.02 ng Au and 0.4 ng Au, with increasing LOD by increasing nanoparticle diameter. The analytical platform was applied to characterization of Au NPs in livers of rats, which were dosed with 10 nm, 60 nm, or a mixture of 10 and 60 nm nanoparticles by intravenous injection. The homogenized livers were solubilized in tetramethylammonium hydroxide (TMAH), and the recovery of Au NPs from the livers amounted to 86-123% of their total Au content. In spite of successful stabilization with bovine serum albumin even in alkaline medium, separation of the Au NPs by AF(4) was not possible due to association with undissolved remains of the alkali-treated liver tissues as demonstrated by electron microscopy images.

  20. Light scattering by soap films

    NARCIS (Netherlands)

    Vrij, A.

    A theory is constructed describing the scattering from a liquid film (e.g., a soap film) of a light beam polarized normal to the plane of incidence. This scattering is due to the small irregular corrugations caused by thermal motion. The interference of the reflected incident beam with its multiple

  1. USING COORDINATED OBSERVATIONS IN POLARIZED WHITE LIGHT AND FARADAY ROTATION TO PROBE THE SPATIAL POSITION AND MAGNETIC FIELD OF AN INTERPLANETARY SHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Ming; Feng, Xueshang; Liu, Ying D. [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing (China); Davies, Jackie A.; Harrison, Richard A. [Rutherford-Appleton Laboratory (RAL) Space, Harwell Oxford (United Kingdom); Owens, Mathew J.; Davis, Chris J., E-mail: mxiong@spacweather.ac.cn [Reading University, Reading (United Kingdom)

    2013-11-01

    Coronal mass ejections (CMEs) can be continuously tracked through a large portion of the inner heliosphere by direct imaging in visible and radio wavebands. White light (WL) signatures of solar wind transients, such as CMEs, result from Thomson scattering of sunlight by free electrons and therefore depend on both viewing geometry and electron density. The Faraday rotation (FR) of radio waves from extragalactic pulsars and quasars, which arises due to the presence of such solar wind features, depends on the line-of-sight magnetic field component B{sub ∥} and the electron density. To understand coordinated WL and FR observations of CMEs, we perform forward magnetohydrodynamic modeling of an Earth-directed shock and synthesize the signatures that would be remotely sensed at a number of widely distributed vantage points in the inner heliosphere. Removal of the background solar wind contribution reveals the shock-associated enhancements in WL and FR. While the efficiency of Thomson scattering depends on scattering angle, WL radiance I decreases with heliocentric distance r roughly according to the expression I∝r {sup –3}. The sheath region downstream of the Earth-directed shock is well viewed from the L4 and L5 Lagrangian points, demonstrating the benefits of these points in terms of space weather forecasting. The spatial position of the main scattering site r{sub sheath} and the mass of plasma at that position M{sub sheath} can be inferred from the polarization of the shock-associated enhancement in WL radiance. From the FR measurements, the local B{sub ∥sheath} at r{sub sheath} can then be estimated. Simultaneous observations in polarized WL and FR can not only be used to detect CMEs, but also to diagnose their plasma and magnetic field properties.

  2. Incident Information Management Tool

    CERN Document Server

    Pejovic, Vladimir

    2015-01-01

    Flaws of\tcurrent incident information management at CMS and CERN\tare discussed. A new data\tmodel for future incident database is\tproposed and briefly described. Recently developed draft version of GIS-­‐based tool for incident tracking is presented.

  3. Compact plane illumination plugin device to enable light sheet fluorescence imaging of multi-cellular organisms on an inverted wide-field microscope.

    Science.gov (United States)

    Guan, Zeyi; Lee, Juhyun; Jiang, Hao; Dong, Siyan; Jen, Nelson; Hsiai, Tzung; Ho, Chih-Ming; Fei, Peng

    2016-01-01

    We developed a compact plane illumination plugin (PIP) device which enabled plane illumination and light sheet fluorescence imaging on a conventional inverted microscope. The PIP device allowed the integration of microscope with tunable laser sheet profile, fast image acquisition, and 3-D scanning. The device is both compact, measuring approximately 15 by 5 by 5 cm, and cost-effective, since we employed consumer electronics and an inexpensive device molding method. We demonstrated that PIP provided significant contrast and resolution enhancement to conventional microscopy through imaging different multi-cellular fluorescent structures, including 3-D branched cells in vitro and live zebrafish embryos. Imaging with the integration of PIP greatly reduced out-of-focus contamination and generated sharper contrast in acquired 2-D plane images when compared with the stand-alone inverted microscope. As a result, the dynamic fluid domain of the beating zebrafish heart was clearly segmented and the functional monitoring of the heart was achieved. Furthermore, the enhanced axial resolution established by thin plane illumination of PIP enabled the 3-D reconstruction of the branched cellular structures, which leads to the improvement on the functionality of the wide field microscopy.

  4. Disentangling overlapping high-field EPR spectra of organic radicals: Identification of light-induced polarons in the record fullerene-free solar cell blend PBDB-T:ITIC

    Science.gov (United States)

    Van Landeghem, Melissa; Maes, Wouter; Goovaerts, Etienne; Van Doorslaer, Sabine

    2018-03-01

    We present a combined high-field EPR and DFT study of light-induced radicals in the bulk heterojunction blend of PBDB-T:ITIC, currently one of the highest efficiency non-fullerene donor:acceptor combinations in organic photovoltaics. We demonstrate two different approaches for disentangling the strongly overlapping high-field EPR spectra of the positive and negative polarons after charge separation: (1) relaxation-filtered field-swept EPR based on the difference in T1 spin-relaxation times and (2) field-swept EDNMR-induced EPR by exploiting the presence of 14N hyperfine couplings in only one of the radical species, the small molecule acceptor radical. The approach is validated by light-induced EPR spectra on related blends and the spectral assignment is underpinned by DFT computations. The broader applicability of the spectral disentangling methods is discussed.

  5. Disentangling overlapping high-field EPR spectra of organic radicals: Identification of light-induced polarons in the record fullerene-free solar cell blend PBDB-T:ITIC.

    Science.gov (United States)

    Van Landeghem, Melissa; Maes, Wouter; Goovaerts, Etienne; Van Doorslaer, Sabine

    2018-03-01

    We present a combined high-field EPR and DFT study of light-induced radicals in the bulk heterojunction blend of PBDB-T:ITIC, currently one of the highest efficiency non-fullerene donor:acceptor combinations in organic photovoltaics. We demonstrate two different approaches for disentangling the strongly overlapping high-field EPR spectra of the positive and negative polarons after charge separation: (1) relaxation-filtered field-swept EPR based on the difference in T 1 spin-relaxation times and (2) field-swept EDNMR-induced EPR by exploiting the presence of 14 N hyperfine couplings in only one of the radical species, the small molecule acceptor radical. The approach is validated by light-induced EPR spectra on related blends and the spectral assignment is underpinned by DFT computations. The broader applicability of the spectral disentangling methods is discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Light Sources and Lighting Circuits

    Science.gov (United States)

    Honda, Hisashi; Suwa, Takumi; Yasuda, Takeo; Ohtani, Yoshihiko; Maehara, Akiyoshi; Okada, Atsunori; Komatsu, Naoki; Mannami, Tomoaki

    means of using filler gas with a higher atomic weight. Regarding fluorescent lamps, studies and developments for longer operating life and improvement in the lumen maintenance factor for the straight-type and circular-type fluorescent lamps were actively pursued. Regarding self-ballasted fluorescent lamps, the main stream of development was aimed at reducing lamp size and increasing energy conservation, and the development of new products that took advantage of these features proceeded. In regard to LED light sources, basic research and product development, including new application development, were vigorously implemented. In basic research, studies were reported, not only on efficacy improvements through optimization of the LED chips, phosphor layers, and packaging technology, but also on photometry, colorimetry, and visual psychology. In the field of application, applications were studied for general lighting sources and also for a wide range of fields, such as automotive headlights and visible light communication. Also, many academic conferences and exhibitions were held domestically and overseas, and the high level of interest suggests high expectations for this next-generation light source. Regarding HID lamps, there was much activity in research and development and in the commercialization of the ceramic metal halide lamp product, and products were commercialized with features such as higher efficiency (130 lm/W) and higher color rendering properties (R9 ≥ 90). In the high-pressure sodium lamps, there were many study reports concerning plant growth and insect pest control using its low insect-attracting characteristics. With high-pressure mercury lamps, there were many reports on reducing lamp size and increasing intensity for use as a light source for projectors.

  7. Light Trapping with Silicon Light Funnel Arrays

    Directory of Open Access Journals (Sweden)

    Ashish Prajapati

    2018-03-01

    Full Text Available Silicon light funnels are three-dimensional subwavelength structures in the shape of inverted cones with respect to the incoming illumination. Light funnel (LF arrays can serve as efficient absorbing layers on account of their light trapping capabilities, which are associated with the presence of high-density complex Mie modes. Specifically, light funnel arrays exhibit broadband absorption enhancement of the solar spectrum. In the current study, we numerically explore the optical coupling between surface light funnel arrays and the underlying substrates. We show that the absorption in the LF array-substrate complex is higher than the absorption in LF arrays of the same height (~10% increase. This, we suggest, implies that a LF array serves as an efficient surface element that imparts additional momentum components to the impinging illumination, and hence optically excites the substrate by near-field light concentration, excitation of traveling guided modes in the substrate, and mode hybridization.

  8. Asymmetric Flow Field Flow Fractionation of Aqueous C60 Nanoparticles with Size Determination by Dynamic Light Scattering and Quantification by Liquid Chromatography Atmospheric Pressure Photo-Ionization Mass Spectrometry

    Science.gov (United States)

    A size separation method was developed for aqueous C60 fullerene aggregates (aqu/C60) using asymmetric flow field flow fractionation (AF4) coupled to a dynamic light scattering detector in flow through mode. Surfactants, which are commonly used in AF4, were avoided as they may al...

  9. Waves in periodic medium. Atomic matter waves in light crystals

    International Nuclear Information System (INIS)

    Oberthaler, M. K.

    1997-07-01

    This work deals with the propagation of matter waves inside a periodic potential. In analogy to photon optics a potential can be described by a refractive index for matter waves. A real potential leads to a refractive spatial structure while an imaginary potential leads to an absorptive structure. A general theoretical description is given in the framework of Floquet theory. The equivalent approach of dynamical diffraction theory will be treated in detail. The analytic solution for weak potentials are given in a general form so that they are applicable for every kind of wave and medium. For our experiments an open two level atom (metastable Argon) propagating inside a standing light wave was used. Detuning the frequency of the light wave from the atomic resonance leads to a real (refractive) periodic potential. Tuning the laser exact on resonance gives rise to a pure imaginary (absorptive) periodic potential. In analogy to solid state crystals in X-ray and neutron optics we call a standing light wave a light crystal. Tuning the standing light field on resonance we demonstrated experimentally the Borrmann effect. This effect describes the increase of the total transmission through a crystal for Bragg incidence. Furthermore, we confirmed that this effect is coherent and that a sinusoidal wave field is formed inside the crystal. The nodes of the wave field were found to coincide with the maxima of absorption. For a detuned standing light field a refractive crystal was realized, for which the expected Pendelloesung effect was demonstrated. In this case the maximum of the wave field inside the crystal was found at the steepest gradient of the potential as predicted by dynamical diffraction theory. Superposing an absorptive and a refractive light crystal a complex light crystal was realized. With such a crystal the violation of Friedel's law was demonstrated in a very clear way. (author)

  10. Diel Variation of Biogenic Volatile Organic Compound Emissions- A field Study in the Sub, Low and High Arctic on the Effect of Temperature and Light

    Science.gov (United States)

    Lindwall, Frida; Faubert, Patrick; Rinnan, Riikka

    2015-01-01

    Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs) may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography- mass spectrometry. Five different arctic vegetation communities were examined: high arctic heaths dominated by Salix arctica and Cassiope tetragona, low arctic heaths dominated by Salix glauca and Betula nana and a subarctic peatland dominated by the moss Warnstorfia exannulata and the sedge Eriophorum russeolum. We also addressed how climate warming affects the 24-hour emission and how the daytime emissions respond to sudden darkness. The emissions from the high arctic sites were lowest and had a strong diel variation with almost no emissions during night-time. The low arctic sites as well as the subarctic site had a more stable release of BVOCs during the 24-hour period with night-time emissions in the same range as those during the day. These results warn against overlooking the night period when considering arctic emissions. During the day, the quantity of BVOCs and the number of different compounds emitted was higher under ambient light than in darkness. The monoterpenes α-fenchene, α -phellandrene, 3-carene and α-terpinene as well as isoprene were absent in dark measurements during the day. Warming by open top chambers increased the emission rates both in the high and low arctic sites, forewarning higher emissions in a future warmer climate in the Arctic. PMID:25897519

  11. Diel Variation of Biogenic Volatile Organic Compound Emissions--A field Study in the Sub, Low and High Arctic on the Effect of Temperature and Light.

    Science.gov (United States)

    Lindwall, Frida; Faubert, Patrick; Rinnan, Riikka

    2015-01-01

    Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs) may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography-mass spectrometry. Five different arctic vegetation communities were examined: high arctic heaths dominated by Salix arctica and Cassiope tetragona, low arctic heaths dominated by Salix glauca and Betula nana and a subarctic peatland dominated by the moss Warnstorfia exannulata and the sedge Eriophorum russeolum. We also addressed how climate warming affects the 24-hour emission and how the daytime emissions respond to sudden darkness. The emissions from the high arctic sites were lowest and had a strong diel variation with almost no emissions during night-time. The low arctic sites as well as the subarctic site had a more stable release of BVOCs during the 24-hour period with night-time emissions in the same range as those during the day. These results warn against overlooking the night period when considering arctic emissions. During the day, the quantity of BVOCs and the number of different compounds emitted was higher under ambient light than in darkness. The monoterpenes α-fenchene, α-phellandrene, 3-carene and α-terpinene as well as isoprene were absent in dark measurements during the day. Warming by open top chambers increased the emission rates both in the high and low arctic sites, forewarning higher emissions in a future warmer climate in the Arctic.

  12. Extraction of hyaluronic acid (HA) from rooster comb and characterization using flow field-flow fractionation (FlFFF) coupled with multiangle light scattering (MALS).

    Science.gov (United States)

    Kang, Dong Young; Kim, Won-Suk; Heo, In Sook; Park, Young Hun; Lee, Seungho

    2010-11-01

    Hyaluronic acid (HA) was extracted in a relatively large scale from rooster comb using a method similar to that reported previously. The extraction method was modified to simplify and to reduce time and cost in order to accommodate a large-scale extraction. Five hundred grams of frozen rooster combs yielded about 500 mg of dried HA. Extracted HA was characterized using asymmetrical flow field-flow fractionation (AsFlFFF) coupled online to a multiangle light scattering detector and a refractive index detector to determine the molecular size, molecular weight (MW) distribution, and molecular conformation of HA. For characterization of HA, AsFlFFF was operated by a simplified two-step procedure, instead of the conventional three-step procedure, where the first two steps (sample loading and focusing) were combined into one to avoid the adsorption of viscous HA onto the channel membrane. The simplified two-step AsFlFFF yielded reasonably good separations of HA molecules based on their MWs. The weight average MW (M(w) ) and the average root-mean-square (RMS) radius of HA extracted from rooster comb were 1.20×10(6) and 94.7 nm, respectively. When the sample solution was filtered through a 0.45 μm disposable syringe filter, they were reduced down to 3.8×10(5) and 50.1 nm, respectively. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A method of incident angle estimation for high resolution spectral recovery in filter-array-based spectrometers

    Science.gov (United States)

    Kim, Cheolsun; Lee, Woong-Bi; Ju, Gun Wu; Cho, Jeonghoon; Kim, Seongmin; Oh, Jinkyung; Lim, Dongsung; Lee, Yong Tak; Lee, Heung-No

    2017-02-01

    In recent years, there has been an increasing interest in miniature spectrometers for research and development. Especially, filter-array-based spectrometers have advantages of low cost and portability, and can be applied in various fields such as biology, chemistry and food industry. Miniaturization in optical filters causes degradation of spectral resolution due to limitations on spectral responses and the number of filters. Nowadays, many studies have been reported that the filter-array-based spectrometers have achieved resolution improvements by using digital signal processing (DSP) techniques. The performance of the DSP-based spectral recovery highly depends on the prior information of transmission functions (TFs) of the filters. The TFs vary with respect to an incident angle of light onto the filter-array. Conventionally, it is assumed that the incident angle of light on the filters is fixed and the TFs are known to the DSP. However, the incident angle is inconstant according to various environments and applications, and thus TFs also vary, which leads to performance degradation of spectral recovery. In this paper, we propose a method of incident angle estimation (IAE) for high resolution spectral recovery in the filter-array-based spectrometers. By exploiting sparse signal reconstruction of the L1- norm minimization, IAE estimates an incident angle among all possible incident angles which minimizes the error of the reconstructed signal. Based on IAE, DSP effectively provides a high resolution spectral recovery in the filter-array-based spectrometers.

  14. Endoscopic hyperspectral imaging: light guide optimization for spectral light source

    Science.gov (United States)

    Browning, Craig M.; Mayes, Samuel; Rich, Thomas C.; Leavesley, Silas J.

    2018-02-01

    Hyperspectral imaging (HSI) is a technology used in remote sensing, food processing and documentation recovery. Recently, this approach has been applied in the medical field to spectrally interrogate regions of interest within respective substrates. In spectral imaging, a two (spatial) dimensional image is collected, at many different (spectral) wavelengths, to sample spectral signatures from different regions and/or components within a sample. Here, we report on the use of hyperspectral imaging for endoscopic applications. Colorectal cancer is the 3rd leading cancer for incidences and deaths in the US. One factor of severity is the miss rate of precancerous/flat lesions ( 65% accuracy). Integrating HSI into colonoscopy procedures could minimize misdiagnosis and unnecessary resections. We have previously reported a working prototype light source with 16 high-powered light emitting diodes (LEDs) capable of high speed cycling and imaging. In recent testing, we have found our current prototype is limited by transmission loss ( 99%) through the multi-furcated solid light guide (lightpipe) and the desired framerate (20-30 fps) could not be achieved. Here, we report on a series of experimental and modeling studies to better optimize the lightpipe and the spectral endoscopy system as a whole. The lightpipe was experimentally evaluated using an integrating sphere and spectrometer (Ocean Optics). Modeling the lightpipe was performed using Monte Carlo optical ray tracing in TracePro (Lambda Research Corp.). Results of these optimization studies will aid in manufacturing a revised prototype with the newly designed light guide and increased sensitivity. Once the desired optical output (5-10 mW) is achieved then the HIS endoscope system will be able to be implemented without adding onto the procedure time.

  15. Public lighting.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1986-01-01

    The function of public lighting and the relationship between public lighting and accidents are considered briefly as aspects of effective countermeasures. Research needs and recent developments in installation and operational described. Public lighting is an efficient accident countermeasure, but

  16. Light Pollution

    Science.gov (United States)

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  17. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques

    Directory of Open Access Journals (Sweden)

    O. Schmid

    2006-01-01

    Full Text Available Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP, have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ Aethalometer became commercially available, which covers the visible (VIS to near-infrared (NIR spectral range (λ=450–950 nm, and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999. On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering, which is significantly larger than the factors previously reported (~2 for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external as a likely cause. For

  18. Investigations on magnetic field induced optical transparency in magnetic nanofluids

    Science.gov (United States)

    Mohapatra, Dillip Kumar; Philip, John

    2018-02-01

    We study the magnetic field induced optical transparency and its origin in magnetic nanoemulsion of droplets of average size ∼200 nm containing superparamagnetic iron oxide nanoparticles. Beyond a certain volume fraction (Φ > 0.0021) of magnetic nanoemulsion and a critical magnetic field (Hc1), the transmitted light intensity increases drastically and reaches a maximum at another critical magnetic field (Hc2), beyond which the transmitted light intensity decreases and reaches a plateau. Interestingly, the transmitted light intensity at Hc2 is found to increase linearly with Φ and the critical magnetic fields Hc1 and Hc2 follow power law decay with Φ (i.e. Hc ∼ Φ-x), with exponents 0.48 and 0.27, respectively. The light intensity recovers to its initial value when the magnetic field is switched off, indicating the perfect reversibility of the field induced transparency process. The observed straight line scattered patterns above Hc2, on a screen placed perpendicular to the incident beam, confirms the formation of rod like anisotropic nanostructures perpendicular to the direction of light propagation. The magneto-optical measurements in the emulsion confirm that the observed field induced transparency in magnetic emulsions for Φ > 0.0021 is due to the optical birefringence caused by the rod like nanostructures. The reduced birefringence is found to be proportional to the square of the applied magnetic field. This finding offers several possibilities in using magnetic nanofluids in tunable optical devices.

  19. Goos-Hänchen shifts of partially coherent light beams from a cavity with a four-level Raman gain medium

    Science.gov (United States)

    Ziauddin; Lee, Ray-Kuang; Qamar, Sajid

    2016-09-01

    We theoretically investigate spatial and angular Goos-Hänchen (GH) shifts (both negative and positive) in the reflected light for a partial coherent light incident on a cavity. A four-level Raman gain atomic medium is considered in a cavity. The effects of spatial coherence, beam width, and mode index of partial coherent light fields on spatial and angular GH shifts are studied. Our results reveal that a large magnitude of negative and positive GH shifts in the reflected light is achievable with the introduction of partial coherent light fields. Furthermore, the amplitude of spatial (negative and positive) GH shifts are sharply affected by the partial coherent light beam as compared to angular (negative and positive) GH shifts in the reflected light.

  20. Theoretical comparison of light scattering and guided wave coupling in multilayer coated optical components with random interface roughness

    International Nuclear Information System (INIS)

    Elson, J.M.

    1995-01-01

    In this work, we use first-order perturbation theory to calculate and then compare the (1) angular distribution of incident light scattered from a multilayer-coated optical component and (2) the angular distribution of incident light coupled into guided waves supported by the multilayer component. The incident beam is assumed to be a monochromatic plane wave and the scattering/coupling is assumed to be caused by roughness at the interfaces of the optical component. Numerical results show that for high quality (low root mean square roughness) optical components, comparison of the relative amounts of incident energy (1) scattered out of the specular beam and (2) coupled into guided waves are comparable. It follows that the guided wave energy will further contribute to the scattered field via radiative decay or be converted to heat. Thus, this work can help provide an estimation of when guided wave coupling can occur along with the expected magnitude. (orig.)