Energy Technology Data Exchange (ETDEWEB)

Papers are presented in the areas of: Medical Technologies; Non-Destructive Evaluation; Applications of Signal/Image Processing; Laser Guide Star and Adaptive Optics; Computational Electromagnetic, Acoustics and Optics; Micro-Impulse Radar Processing; Optical Applications; TANGO Space Shuttle.

UK PubMed Central (United Kingdom)

In vivo two-photon imaging through the pupil of the primate eye has the potential to become a useful tool for functional imaging of the retina. Two-photon excited fluorescence images...Full Text Available

UK PubMed Central (United Kingdom)

The 3-D spectral-domain optical coherence tomography (SD-OCT) images of the retina often do not reflect the true shape of the retina and are distorted differently along the x and y...Full Text Available

Science.gov (United States)

... is the sensor that converts incoming photons into a ... with CCD foundries to acquire such a sensor. ... 2007, Journal of Spacecraft and Rockets, 44, 910 ...

CERN Document Server

The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for a fully automated, ultra-wide-field survey aimed at detecting the prompt optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the HETE-2 and Swift/BAT pointing directions covering a total field of view of 62 degree x 62 degree every 10 secounds using an unfiltered system. This monitoring survey allows exploration of the optical emission before the gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r' system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten simultaneous and one pre-trigger GRB observations. The efficiency of synchronized observation with HETE-2 is four times better than that of Swift. There has been no bright optical emission similar to that from GRB 080319B. The statistical analysis implies that GRB080319B is a rare event. This paper ...

Energy Technology Data Exchange (ETDEWEB)

The present conference on lens design encompasses physical and geometrical optics, diffractive optics, the optimization of optical design, software packages, ray tracing, the use of artificial intelligence, the achromatization of materials, zoom optics, microoptics and GRIN lenses, and IR lens design. Specific issues addressed include diffraction-performance calculations in lens design, the optimization of the optical transfer function, a rank-down method for automatic lens design, applications of quadric surfaces, the correction of aberrations by using HOEs in UV and visible imaging systems, and an all-refractive telescope for intersatellite communications. Also addressed are automation techniques for optics manufacturing, all-reflective phased-array imaging telescopes, the thermal aberration analysis of a Nd:YAG laser, ...

Science.gov (United States)

Sep 3, 2010 ... These higher-quality deformable mirrors will enable diffraction-limited performance for many space-based optical systems such as space-based ...

UK PubMed Central (United Kingdom)

A two-channel optical system has been developed to provide spatially resolved simultaneous imaging of singlet molecular oxygen (¹O₂) phosphorescence and photosensitizer (PS) fluorescence...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

We investigated the efficacy of combined FDG-PET/CT imaging for the diagnosis of small-size uveal melanomas and the feasibility of combining separate, high-resolution (HR) FDG-PET with MRI for its improved localization and detection. Patients, methods: 3 patients with small-size uveal melanomas (0.2-1.5 ml) were imaged on a combined whole-body PET/CT, a HR brain-PET, and a 1.5 T MRI. Static, contrast-enhanced FDG-PET/CT imaging was performed of head and torso with CT contrast enhancement. HR PET imaging was performed in dynamic mode 0-180 min post-injection of FDG. MRI imaging was performed using a high-resolution small-loop-coil placed over the eye in question with T2-3D-TSE and T1-3D-SE with 18 ml Gd-contrast. Patients had their eyes shaded during the scans. Lesion visibility on high-resolution FDGPET images was graded for confidence: 1: none, 2: suggestive, ...

Energy Technology Data Exchange (ETDEWEB)

X-ray diffraction enhanced imaging (DEI) is one of X-ray phase-contrast imaging methods, which is applied to inspect internal structures of weakly absorbing low-Z samples. The key problem of the DEI is how to extract phase information which is expressed by refraction-angle images from a series of DEI images measured in different positions of the rocking curve of the analyzer. Three effective extraction methods are presented in this paper: the statistical geometric-optics-approximation method, the maximum refraction-angle method and the Gaussian curve fitting method. They are compared with the existing methods, such as the D. Chapman's geometric optics approximation method and the multiple-images statistical method. A 2D computer simulation experiment is performed to draw comparisons of these methods. The experimental results prove ...

British Library Electronic Table of Contents (United Kingdom)

Non-linear optics encompasses a range of optical phenomena, including two- and three-photon fluorescence, second harmonic generation (SHG), sum frequency generation (SFG), difference frequency generation (DFG), third harmonic generation (THG), coherent anti-Stokes Raman scattering (CARS), and stimulated Raman scattering (SRS). The combined advantages of using these phenomena for imaging complex pharmaceutical systems include chemical and structural specificities, high optical spatial and temporal resolutions, no requirement for labels, and the ability to image in an aqueous environment. These features make such imaging well suited for a wide range of pharmaceutical and biopharmaceutical investigations, including material and dosage form characterisation, dosage form digestion and drug rele...

Energy Technology Data Exchange (ETDEWEB)

A subsurface imaging system is utilized to test the ability of the spectral polarization difference imaging technique for deep subsurface imaging in tissues. The illumination of the system is derived from compact class III lasers in the red and NIR spectral region and, alternatively, from a white light source and selection of the appropriate illumination wavelength using band-pass optical filters. The experimental results demonstrate detection and imaging of a high-scattering object located up to 1.5 cm underneath the surface of a host chicken tissue.

International Nuclear Information System (INIS)

A photoacoustic (PA) imaging system based on an ultrasonic Fresnel zone plate (FZP) transducer is developed for the purpose of imaging biological tissue. This FZP transducer has a two-zone negative zone plate piezoelectric material pattern, and an optical fibre is integrated with the transducer on the symmetric axis of the zone plates to deliver laser pulses to the sample. The focal characteristic of the FZP transducer is analysed by theoretical prediction and experimental measurement, and the measured results are in good agreement with the predicted results. The limited-field back-projection deconvolution algorithm combined with the coherence-factor weighting technique is used to reconstruct the optical absorption distribution. The experiments were performed with phantoms and the blood vessels of chicken embryo chorioallantoic membrane. The results demonstrate that PA imaging using ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Here we propose a software for the estimation of the occupied area and volume of fungal cultures. This software was developed using a Matlab platform and allows analysis of high-definition images from optical, electronic or atomic force microscopes. In a first step, a single hypha grown on potato dextrose agar was monitored using optical microscopy to estimate the change in occupied area and volume. Weight measurements were carried out to compare them with the estimated volume, revealing a slight difference of less than 1.5%. Similarly, samples from two different solid-state fermentation cultures were analyzed using images from a scanning electron microscope (SEM) and an environmental SEM (ESEM). Occupied area and volume were calculated for both samples, and the results obtained w...

International Nuclear Information System (INIS)

A possible novel application of hard x-ray emitted during laser-plasma interaction was discussed. The authors established an Optical Transform Function to study the joint effect of the spectral distribution and temporal profile of the laser-produced x-ray on x-ray phase imaging. Though the laser-produced x-ray pulse duration is short and incoherent, the analysis confirms that the current x-ray phase imaging theory still holds for laser-produced x-ray phase imaging

International Nuclear Information System (INIS)

ASTROSAT, India's first dedicated astronomy satellite is slated for launch in 2007. The primary science objective of ASTROSAT is to explore the Universe using broad-band instruments covering optical, UV, soft X-ray and hard X-ray studies

Science.gov (United States)

Quantitative metallography is often used to confirm the proper processing of aerospace metallic materials. A microstructural feature of great importance for titanium alloys processed in the alpha-beta phase field is the volume fraction of primary alpha. S...

International Nuclear Information System (INIS)

Based on a recently introduced phase X-ray imaging approach, a dual-detector prototype was developed for in-line X-ray phase imaging and phase retrieval utilizing a micro-focus X-ray source and two computed radiography (CR) cassette detectors. The system was built on a horizontal optical rail to facilitate manual adjustment of the positions of the X-ray source, the sample and the detectors. The novel design of the detector-1 is essential, it detects a portion of radiation to form an attenuation image; allows the rest of radiation to reach the detector-2 to form a phase contrast image, and the two images are used to retrieve a phase map. The two detectors are balanced for optimal phase-retrieval with reasonable radiation dose to the object to be imaged. The system was examined in terms of the linearity, the fractions of the X-ray photons ...

Science.gov (United States)

We present a field-portable lensfree tomographic microscope, which can achieve sectional imaging of a large volume (?20 mm(3)) on a chip with an axial resolution of Hymenolepis nana egg, which is an infectious parasitic flatworm. Achieving a decent three-dimensional spatial resolution, this field-portable on-chip optical tomographic microscope might provide a useful toolset for telemedicine and high-throughput imaging applications in resource-poor settings. PMID:21573311

International Nuclear Information System (INIS)

The determination of optical parameter type in x-ray pelvimetry was performed on 59 subjects using Fuji computed radiography (FCR). Excellent measurable images were obtained at GT (type A), RT (type P), GA (1.6) and RN (2.0). To reduce maternal and fetal exposure to radiation, the doses were progressively decreased to 50%, 25%, 12.5%, 6.3%, that of conventional screen/film system. One-eighth per cent of conventional radiation dose was minimum for FCR at which measurable images could be obtained. Thereby drastically reducing the radiological exposure to both mother and fetus was possible to obtain measurable images in FCR. (author).

CERN Document Server

We present here the preliminary design of ARIES-Devasthal Faint Object Spectrograph and Camera (ADFOSC), which is a multi-mode instrument for both imaging and spectroscopy. ADFOSC is the first-generation instrument to be mounted at the axial port of the Cassegrain focus on our new 3.6m optical telescope to be installed at Devasthal, Nainital. The main design goals of the instrument are : the instrument will have capability of broad- and narrow-band imaging, low-medium resolution spectroscopy, and imaging polarimetry. The operating wavelength range will be from 360 to 1000 nm and the instrument will have remote-control capability.

Energy Technology Data Exchange (ETDEWEB)

Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes Fuji computed radiography (FCR) of Fuji Film for NDT (non-destructive testing). Imaging plate (IP) is a two-dimensional detector of X-ray, and shows higher photographic sensitivity than X-ray film. The output emission of IP provides a good linear relationship to X-ray intensity in a wide intensity range. When this emission can be digitized, the X-ray intensity can be also digitized. IP is applied to NDT as an inspection using X-ray. FCR provides higher photographic sensitivity than the conventional X-ray film method, which results in one-fifth to one-twentieth of irradiation time. Images with stable density can be obtained independent of the intensity. Since IP has a wide dynamic range, the variation of X-ray intensity of 1:500 can be expressed in a single image by single shot. High density record including 1000 images can be done using a 5.25 inch optical disk ...

International Nuclear Information System (INIS)

Objective: To compare pediatric patients with periventricular leukomalacia (PVL) with normal children by using diffusion tensor MR imaging. Methods: Diffusion tensor images were obtained in 15 pediatric patients with PVL and 15 age-matched normal children. Regions of interest were drawn to measure the fractional anisotropy (FA) in bilateral posterior limb of internal capsule, bilateral optic radiation, genu of corpus callosum, and splenium of corpus callosum. The values of PVL patients and normal children were compared using non-dependent samples T-test. Results: The FA values of regions of interest prescribed were significantly lower in PVL patients than in normal children (P<0.01). Conclusion: Diffusion tensor imaging may reveal retard of myelination of fiber tracts in PVL patients. It can be a potential tool in evaluating the brain development of children. (authors)

Science.gov (United States)

We have developed a novel laser ray-tracing method to measure aberrations in optical systems. It consists of delivering narrow laser pencils (by a laser scanner), recording the spots that are formed on the image plane (with a CCD camera), and computing the position of each centroid. This approach could be considered an experimental (approximate) implementation of standard numerical ray tracing. Several tests and experiments, including a direct comparison with a Hartmann-Shack wave-front sensor, provided highly satisfactory results that confirmed the validity of the method and revealed potential advantages. PMID:18073906

Science.gov (United States)

Raytheon's Santa Barbara Remote Sensing (SBRS) division designed and built the MTSAT-1R Japanese Advanced Meteorological Imager for the Japanese Ministry of Transport between March, 1999 and July, 2002. In order to meet the stressing requirements of a geosynchronous orbit, a combination of structural, thermal, and optical (STOP) analyses were used to design and optimize the beryllium three-mirror anastigmat (TMA) telescope. This modeling approach was used to characterize and minimize the thermal distortion around local midnight. On-orbit temperatures and structural deformations were predicted using thermal Desktop/SINDA and PATRAN/NASTRAN software, respectively. The resulting optical performance was evaluated using Raytheon developed HEXAGON software. The telescope design was successfully optimized to attain specified visible channel performance for most of the 24 hour orbit.

CERN Document Server

We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities > 100 mJy at 500 um, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 um data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with Av ~4 to 5 and star formation rates of ~100 M_sun/yr. They have low gas fractions and low dynamical masses compared to 850 um selected galaxies.

Energy Technology Data Exchange (ETDEWEB)

High-spatial-resolution microfocus-based X-ray imaging technology, both real-time and film, has been used to study the thickness variation that occurs in the oxide core of silver-sheathed BSCCO ribbons produced by the powder-in-tube method. This thickness variation (also called ``sausaging``) occurs during incremental rolling and degrades the critical current densities of the ribbons. Using X-ray image data the authors determined the onset and severity of sausaging. Onset occurred at a ribbon thickness of 203 {micro}m, and the severity increased with subsequent rolling reductions. Scanning electron microscopy was used to confirm the X-ray image data. X-ray imaging provides several advantages over more traditional methods for characterizing the superconductors such as optical or scanning electron microscopy. The X-ray imaging provides nondestructive information ...

International Nuclear Information System (INIS)

Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity-several tens of percent-with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo ...

Science.gov (United States)

This is an inquiry-based module created specifically for use with the PhET simulation Geometric Optics. It includes a lesson plan for teaching about convex lenses, step-by-step student directions, and a set of Power Point "clicker" questions for use as warm-up questions or informal assessment. This resource is part of a larger collection of interactive Java simulations for students of physics, developed by the Physics Education Technology project at the University of Colorado.

Energy Technology Data Exchange (ETDEWEB)

To evaluate the usefulness of portable chest radiographs by Fuji computed radiography (FCR) in ICU, FCR radiographs of 56 patients who were admitted to General Intensive Care Unit of Keio University Hospital were compared with the conventional portable images. Because FCR could show two differently processed images in one film and allowed a wide range of image reproduction, visualization of the trachea, bone soft tissues and catheters by FCR was easier than that by the conventional radiography. Repeated radiographs by FCR had similar optical densities and limited exposure errors. Furthermore, radiation was reduced than that of the conventional radiography. In conclusion, FCR is thought to be a useful technique for portable chest radiography in ICU patients. (author).

International Nuclear Information System (INIS)

The optical properties and microstructure of germanium (Ge) films, prepared by ion-assisted deposition (IAD) process, were investigated. The Ge films were deposited on sapphire and silicon substrates, with and without simultaneous Ar+ bombardment. Higher index films, with a refractive index 7.7% larger than that of the single crystalline Ge wafer, were obtained with the IAD process. The density of the IAD film could be 1.5% greater than that of the e-beam film. The results of the heat treatment indicated that the optical and structural properties of the IAD films were more stable. Ge nano-crystallites could be observed under high ion power density, which induced a crystalline structure in the Ge thin films. The average size of the nano-crystallites, as determined from both the X-ray diffraction data and the transmission electron microscopy images, showed that no systematic change had occurred. The results presented in this ...

Science.gov (United States)

Laser devices are currently in widespread use in particular by armed forces for different tasks. Electro-optical sensors as well as unprotected human eyes are extremely sensitive to laser radiation and can be permanently damaged from direct or reflected beams. Laser damage depends on the interaction between the laser beam and the atmosphere in which it traverses. The atmospheric conditions, including the range, terrain features, turbulence, and atmospheric particulates, may alter the laser's effect on different electro-optical devices and systems. When a laser beam passes through the atmosphere the optical turbulence affects the beam. As a result, temporal intensity fluctuations (scintillations) or spatial variations in intensity within a beam cross-section occur. Atmospheric scintillations pose a safety problem because an observer or sensor can be subjected to the risk of a localized irradiance (local focusing effect) much ...

Science.gov (United States)

Endogenous fluorescence provides morphological, spectral, and lifetime contrast that can indicate disease states in tissues. Previous studies have demonstrated that two-photon autofluorescence microscopy (2PAM) can be used for noninvasive, three-dimensional imaging of epithelial tissues down to approximately 150 ?m beneath the skin surface. We report ex-vivo 2PAM images of epithelial tissue from a human tongue biopsy down to 370 ?m below the surface. At greater than 320 ?m deep, the fluorescence generated outside the focal volume degrades the image contrast to below one. We demonstrate that these imaging depths can be reached with 160 mW of laser power (2-nJ per pulse) from a conventional 80-MHz repetition rate ultrafast laser oscillator. To better understand the maximum imaging depths that we can achieve in epithelial tissues, we studied image contrast as a ...

Science.gov (United States)

The purpose of this study was to develop a simple motion measurement system with magnetic resonance (MR) compatibility and safety. The motion measurement system proposed here can measure 5-DoF motion signals without deteriorating the MR images, and it has no effect on the intense and homogeneous main magnetic field, the temporal-gradient magnetic field (which varies rapidly with time), the transceiver radio frequency (RF) coil, and the RF pulse during MR data acquisition. A three-axis accelerometer and a two-axis gyroscope were used to measure 5-DoF motion signals, and Velcro was used to attach a sensor module to a finger or wrist. To minimize the interference between the MR imaging system and the motion measurement system, nonmagnetic materials were used for all electric circuit components in an MR shield room. To remove the effect of RF pulse, an amplifier, modulation circuit, and power supply were located in a shielded case, which was made ...

Science.gov (United States)

... lasers, model switched optical memory elements ... Optical RS flip flop, Acousto-optic switches. ... FLOP CIRCUITS, OPTICAL SWITCHING, NOR GATES ...

British Library Electronic Table of Contents (United Kingdom)

The development of calcium sulfate dihydrate (gypsum) mineral scale in reverse osmosis (RO) membrane desalting was investigated by direct real-time observation of crystal growth. Gypsum scaling studies were conducted in a specially modified plate-and-frame reverse osmosis cell fitted with an optical window, with dark-field membrane lighting arrangement within the membrane cell to enhance crystal boundaries and allow recording of digital surface images magnified through an optical microscope. The evolution of the surface number density (SND) of gypsum crystals resembled a sigmoidal population growth process with an increasing rate of crystal formation at higher solution supersaturation (with respect to gypsum) at the membrane surface. The rate of formation of new crystals declined as the su...

Science.gov (United States)

Optical measurement of the Doppler shift of laser backscatter, using a near-IR, visible, or ultraviolet laser, is potentially more robust and field reliable than coherent, heterodyne measurement with an IR laser. The direct measurement of the displacement of Fabry-Perot interference fringes is possible, but entails expensive, technically challenging, imaging detectors. The 'edge technique' permits Doppler shift measurements with relatively simple detectors and detector electronics, and has been implemented with Fabry-Perot etalons and with atomic line filters. Simple analytical models of the fringe imaging and edge detection techniques are presented, permitting ready calculation of the potential performance of either, for various atmospheric conditions and for various lidar hardware configurations. The predictions of the analytical models are confirmed by computer models, which in turn allow more detailed considerations of ...

British Library Electronic Table of Contents (United Kingdom)

Drosophila melanogaster is a model organism rich in genetic tools to manipulate and identify neural circuits involved in specific behaviors. Here we present a technique for two-photon calcium imaging in the central brain of head-fixed Drosophila walking on an air-supported ball. The ball's motion is tracked at high resolution and can be treated as a proxy for the fly's own movements. We used the genetically encoded calcium sensor, GCaMP3.0, to record from important elements of the motion-processing pathway, the horizontal-system lobula plate tangential cells (LPTCs) in the fly optic lobe. We presented motion stimuli to the tethered fly and found that calcium transients in horizontal-system neurons correlated with robust optomotor behavior during walking. Our technique allows both behavior ...

CERN Document Server

To understand dynamic developmental processes, living tissues must be imaged frequently and for extended periods of time. Root development is extensively studied at cellular resolution to understand basic mechanisms underlying pattern formation and maintenance in plants. Unfortunately, ensuring continuous specimen access, while preserving physiological conditions and preventing photo-damage, poses major barriers to measurements of cellular dynamics in indeterminately growing organs such as plant roots. We present a system that integrates optical sectioning through light sheet fluorescence microscopy with hydroponic culture that enables us to image at cellular resolution a vertically growing Arabidopsis root every few minutes and for several consecutive days. We describe novel automated routines to track the root tip as it grows, track cellular nuclei and identify cell divisions. We demonstrate the system's capabilities by ...

British Library Electronic Table of Contents (United Kingdom)

Luminescent materials are widely used for imaging and sensing owing to their high sensitivity, rapid response and facile detection by many optical technologies. Typically materials must be chemically tailored to achieve intense, photostable fluorescence, oxygen-sensitive phosphorescence or dual emission for ratiometric sensing, often by blending two dyes in a matrix. Dual-emissive materials combining all of these features in one easily tunable molecular platform are desirable, but when fluorescence and phosphorescence originate from the same dye, it can be challenging to vary relative fluorescence/phosphorescence intensities for practical sensing applications. Heavy-atom substitution alone increases phosphorescence by a given, not variable amount. Here, we report a strategy for modulating ...

International Nuclear Information System (INIS)

We will describe recent improvements to the SPEAR reflectometer at the Manuel Lujan Jr. Neutron Scattering Center at Los Alamos. One of the changes consists of wider convergent, incident-beam, collimation to take advantage of optical imaging for specular scattering. In addition, the instrument now views a partially coupled liquid hydrogen moderator as opposed to the decoupled moderator that was previous in-place. While the wavelength distribution is poorer, it matches the time (wavelength) resolution of the reflectometer more closely with the angular resolution. Since the integrated intensity of the partially coupled moderator is higher than the decoupled moderator, we show a similar gain in incident beam flux on the sample without loss of the ability to separate fringes. The increases in intensity from the moderator gain and the improved collimation combine to allow us to measure reflectivities with good statistics down to 10"-"4 in a matter ...

CERN Document Server

Gemini North adaptive optics imaging spectroscopy is presented for the Galactic ultra-compact HII (UCHII) region K3-50A. Data were obtained in the K-band using the Near-infrared Integral Field Spectrograph (NIFS) behind the facility adaptive optics module ALTAIR in natural guide star mode. The NIFS data cube reveals a complex spatial morphology across the 0.1 pc scale of the 3'' UCHII region. Comparison of the nebular emission to Cloudy ionization models shows that the central source must have an effective temperature between about 37000 K and 45000 K with preferred values near 40000 K. Evidence is presented for sharp density variations in the nebula which are interpreted as a clearing of material nearest the central source. High excitation lines of FeIII and SeIV show that the ionization of the nebula clearly changes with distance from the central source. A double lobed kinematic signature (+/- 25 kms) is evident in the Br ...

Energy Technology Data Exchange (ETDEWEB)

This work presents the development of a streak camera 'jitter free' sweep unit synchronized on a femtosecond laser. This application of high voltage photoconductive switches ('High voltage Auston switch') yields subpicosecond resolution for accumulated images on streak camera on a few hundreds micro joule femtosecond laser. Two others applications of these photoconductive switches are studied: - ultrafast optical commutation by a Pockels cell directly driven by a photoconductive switch (rising edge < 100 ps and jitter < 2 ps), - laser pulse energy self-stabilization experimentally proving that driving a Pockels cell by a photoconductive switch can increase the stability of the laser pulse energy from 7 % to 0.7 % rms. Additionally, the application of the acoustic-optical programmable dispersive filter (Dazzler) to the self referenced spectral phase measurement is presented. ...

CERN Document Server

The airborne traffic monitoring system forms a novel technology of detecting vehicle motion. An optical digital camera located on an airborne platform produces a series of images which then are processed to recognized the fixed vehicles. In this way the video data are converted into the time sequence of frames containing the vehicle coordinates. In the present work a three-frame algorithm is developed to identify the succeeding vehicle positions. It is based on finding the neighboring points in the frame sequence characterized by minimal acceleration. To verify and optimize the developed algorithm a ``Virtual Road'' simulator was created. Finally available empirical data are analyzed using the created algorithm.

Energy Technology Data Exchange (ETDEWEB)

Accurate automated alignment of laser beams in the National Ignition Facility (NIF) is essential for achieving extreme temperature and pressure required for inertial confinement fusion. The alignment achieved by the integrated control systems relies on algorithms processing video images to determine the position of the laser beam images in real-time. Alignment images that exhibit wide variations in beam quality require a matched-filter algorithm for position detection. One challenge in designing a matched-filter based algorithm is to construct a filter template that is resilient to variations in imaging conditions while guaranteeing accurate position determination. A second challenge is to process the image as fast as possible. This paper describes the development of a new analytical template that captures key recurring features present in the beam image to ...

Science.gov (United States)

... Abstract : The acousto-optic filter (AOF) is ... for large switch networks. ... FOURIER TRANSFORMATION, OPTICAL SWITCHING, SURFACE ACOUSTIC ...

CERN Document Server

Aims: I have analyzed a sample of seven nearby edge-on galaxies observed in the V and K'-band, in order to infer the properties of the dust distribution. Methods: A radiative transfer model, including scattering, have been used to decompose each image into a stellar disk, a bulge, and a dust disk. The parameters describing the distributions have been obtained through standard X^2 minimization techniques. Results: The dust disks fitted to the V-band images are consistent with previous work in literature: the radial scalelength of dust is larger than that for stars (h_d/h_s ~ 1.5); the dust disk has a smaller vertical scalelength than the stellar (z_d/z_s ~ 1/3); the dust disk is almost transparent when seen face-on (central, face-on, optical depth tau_0 =0.5-1.5). Faster radiative transfer models which neglect scattering can produce equivalent fits, with changes in the derived parameters within the accuracy of full fits ...

Energy Technology Data Exchange (ETDEWEB)

A real-time neutron radiography imaging system has been installed at the Texas A and M University Nuclear Science Center. The system employs a scintillating screen viewed by a low-light TV camera with a front surface mirror placed at 45deg to the neutron beam. The key components of the system are the neutron camera and the image capture and processing unit. The neutron camera uses an NE 426 scintillating screen (ZnS), front surface mirror, remote focus and zoom lens, intensified relay optics (IRO) and monochrome CCD television camera. The image capture and processing unit consists of an IBM PC AT-compatible computer, arithmetic frame grabber, frame processor and high-resolution color monitor. The neutron camera is similar to others using a silicon intensified target (SIT) television camera to provide a TV image of the low-level light from a NE 426 screen. The IRO and CCD camera are ...

International Nuclear Information System (INIS)

There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise ...

International Nuclear Information System (INIS)

Events detected in a shielded plastic scintillation counter occurring in the 26 microsec preceding the arrival of an extensive air shower at ground level with local electron density or = 20 m to the -2 power and the 240 microsec after its arrival have been studied. No significant excess of events (tachyons) arriving in the early time domain have been observed in a sample of 11,585 air shower triggers.

Energy Technology Data Exchange (ETDEWEB)

The measurement of q{sub o} is extremely important for understanding the quantity of matter in our universe. The measurement of q{sub o} using supernovae of type Ia as standard candles is appealing because it requires less modeling than other methods using galaxies. The challenge with using supernovae to measure q{sub o} is in finding enough of them. In order to find supernovas, we have constructed a very popular f/1 camera for the 3.9m Anglo-Australian Telescope. The camera uses reducing optics that put a 17 in. {times} 17 in. field on a 1024 {times} 1024 pixel Thomson CCD. Using this system, we image to 23rd magnitude in five minutes. We have developed a software package that uses image subtraction to find supernovae that are approximately magnitude 22.4 or brighter in these images. One field can be processed every 6.6 minutes on a relatively unloaded VAX 6000-6510. We estimate that this system should ...

Science.gov (United States)

Not Available

CERN Document Server

We present a Hubble Space Telescope image of the FRII radio galaxy 3C 401, obtained at 1.6 microns with the NICMOS camera in which we identify the infrared counterpart of the brightest region of the radio jet. The jet has a complex radio structure and brightens where bending occurs, most likely as a result of relativistic beaming. We analyze archival data in the radio, optical and X-ray bands and we derive its spectral energy distribution. Differently from all of the previously known optical extragalactic jets, the jet in 3C401 is not detected in the X-rays even in a long 48ksec X-ray Chandra exposure and the infrared emission dominates the overall SED. We propose that the dominant radiation mechanism of this jet is synchrotron. The low X-ray emission is then caused by two different effects: i) the lack of any strong external photon field and ii) the shape of the electron distribution. This affects the location of the ...

CERN Document Server

Context. We present a multi-wavelength, high-resolution observational survey of the young binary system Haro 6-10 (GV Tau, IRAS 04263+2426), which is harbouring one of the few known infrared companions. Aims. The primary goal of this project is to determine the physical and geometrical properties of the circumstellar and circumbinary material in the Haro 6-10 system. Methods. High-resolution optical (HST/WFPC2) and near-infrared (VLT/NACO) images in different bands were analysed to investigate the large-scale structures of the material around the binary.Mid-infrared interferometry (VLTI/MIDI) and spectroscopy (TIMMI2 at the 3.6m ESO telescope) were carried out to determine the structure and optical depth of the circumstellar material around the individual components. Results. The multi-wavelength observations suggest that both components of the binary system Haro 6-10 are embedded in a common envelope. The measured ...

DEFF Research Database (Denmark)

The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed a reduced blood oxygenation level dependent (BOLD) signal increase and a greater asymmetry in the visual cortex, compared with controls. The volume of visual cortical activation was significantly correlated to the result of the contrast sensitivity test. The BOLD signal increase correlated significantly to both the results of the contrast sensitivity test ...

Energy Technology Data Exchange (ETDEWEB)

Low-energy focused ion beam (FIB) is a useful tool for shallow doping, gas-assisted etching, and other uses to minimize substrate damage in semiconductor device fabrication. The possibility to form a finely FIB of low energy under 1 keV was suggested in the investigations on the retarding mode in electron optical systems. The abilities of the simplest type of retarding mode FIB column are examined here. The optical properties are calculated for the corresponding model and some images are observed with Ga/sup +/ ion beams <0.3 ..mu..m in diameter for beam energies, 10, 5, and 1 keV, using a retarding mode one-lens FIB system. 1-keV and 100-eV Ga/sup +/ FIB was implanted to Ga/As substrate, and the defects are analyzed by deep-level transient spectroscopy. The defect concentration for 100 eV was < (1)/(5) that for 1000 keV.

CERN Document Server

The BL Lacertae object PKS 1413+135 is associated with a disk dominated galaxy which heavily absorbs the BL Lac nucleus at optical and X-ray wavelengths. It has been argued whether this galaxy is actually the host galaxy of PKS 1413+135 or whether the BL Lac is a background QSO, gravitationally lensed by the apparent host galaxy. We have obtained deep high resolution H-band images of this unusual BL Lac object using the UKIRT IRCAM3. Our observations show that the BL Lac nucleus is centered within < 0.05 arcsec of the galaxy. Based on this result we assess the probability for the lensing scenario and come to the conclusion that the disk galaxy is indeed the host of PKS 1413+135. The galaxy shows peanut-shaped isophotes, suggesting the presence of a central bar which is a common feature of AGN

British Library Electronic Table of Contents (United Kingdom)

Size-controllable Ag nanoparticle ultrathin films, which were fabricated by vacuum deposition method from high purity Ag wire onto cleaned indium tin oxide conducting glass, have different color fabricated by variation of preparation conditions. The UV/Vis spectra showed that optical absorption peak of these Ag nanoparticle films can be tuned in a range from 457nm to >650nm. Scanning electron microscopy images showed that with increasing film thickness Ag particle size was larger. Ag/WO3 composite films were prepared by cathodic electrodeposition of WO3 onto the surface of Ag nanoparticle films. Spectroelectrochemistry and electrochromic properties of the resulting composite films were characterized. It was found that the electrochemical and electrochromatic properties of the composite fil...

CERN Document Server

Dusty primordial disks surrounding young low-mass stars are revealing tracers of stellar and planetary formation. The evolution and lifetime of these disks define the boundary conditions of the mechanisms of planet formation. Stellar companions, however, can significantly change this evolution through their tidal interactions. Stellar evolution and planet formation in binaries have to respond to an environment of truncated, quickly disappearing disks--very different compared to an isolated star environment. In order to investigate details of the influence of binarity on circumstellar disk evolution, we obtained adaptive optics supported near-infrared imaging and spectroscopy of the individual components of 22 low-mass binaries in the well-known Orion Nebula Cluster. Brackett gamma emission, which we detect in several systems, is used as a tracer for the presence of an active accretion disk around each binary component. We find a low fraction of ...

British Library Electronic Table of Contents (United Kingdom)

PurposeTo evaluate pathologic features of the photoreceptors in myopic foveoschisis with the Fourier-domain optical coherence tomography (FD-OCT).DesignObservational case series.MethodsSeventeen eyes of 15 patients with myopic foveoschisis (foveal detachment type, six eyes; foveoschisis type, 11 eyes) were included. We observed the photoreceptor inner and outer segments (IS/OS) and evaluated the morphologic status using FD-OCT. Fundus photographs and time-domain OCT (TD-OCT) images also were obtained.ResultsIS/OS defects, which are uncommon in retinal detachments in eyes with myopia, were seen clearly in five eyes (three eyes [50%] with the foveal detachment type; two eyes [18%] with the foveal schisis type). Fundus photographs showed myopic chorioretinal atrophy in eight study eyes (47%),...

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Multi-kilo-electron-volt x-ray microscopy will be an important laser-produced plasma diagnostic at future megajoule facilities such as the National Ignition Facility (NIF). However, laser energies and plasma characteristics imply that x-ray microscopy will be more challenging at NIF than at existing facilities. We use analytical estimates and numerical ray tracing to investigate several instrumentation options in detail, and we conclude that near-normal-incidence single spherical or toroidal crystals may offer the best general solution for high-energy x-ray microscopy at NIF and similar large facilities. Apertured Kirkpatrick{endash}Baez microscopes using multilayer mirrors may also be good options, particularly for applications requiring one-dimensional imaging over narrow fields of view. {copyright} 1998 Optical Society of America

British Library Electronic Table of Contents (United Kingdom)

A fragmented fossil bone incised with the figure of a proboscidean was recently found at Vero Beach, Florida near the location where Late Pleistocene fauna and human bones were recovered from 1913 to 1916. This engraving may represent the oldest and only existing example of Terminal Pleistocene art depicting a proboscidean in the Americas. Because of the uniqueness, rarity, and potential antiquity of this specimen, caution demanded that a variety of tests be used in an attempt to verify its authenticity. The mineralized bone was identified as mammoth, mastodon, or giant sloth. Rare earth element analysis was consistent with the fossil bone being ancient and originating at or near the Old Vero site (8-IR-9). Forensic analysis suggests the markings on the bone are not recent. Optical microsc...

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An exhaustive compendium of normal and abnormal imaging is presented. The following systems and procedures are illustrated by over 2800 captioned illustrations: liver, spleen, and hepatobiliary imaging; perfusion and ventilation lung imaging; thyroid imaging; salivary gland imaging; bone imaging; brain imaging; radionuclide cisternography; blood flow studies; gallium imaging; nuclear cardiology; and renal imaging. Not included in the atlas are adrenal imaging procedures and emission computed tomography. (ERB)

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The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excess should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} ...

International Nuclear Information System (INIS)

A new dedicated UHV STM for investigations at T#<=#5 K is presented. To achieve such low temperatures and to ensure a high thermal stability, the low-temperature (LT) STM described here has a concentric system of bath cryostats. There are openings for tip and sample exchange at low T, and windows with an infrared radiation shield for optical access, which can both be closed by a door mechanism for LT-STM measurements. Efficient vibration isolation is realized by using spring suspension with eddy current damping. With the 3-d coarse positioning unit any region of interest within 5 mm by 5 mm on the sample is accessible even at 5 K. For short turn-around cycles the sample and tip can both be exchanged at low temperatures. Atomically resolved images of Au(111) at 5 K in UHV demonstrate the excellent performance of this LT STM. As a typical application example the appearance of a charge-density wave on NbSe_2, which occurs below a transition ...

Science.gov (United States)

... The acousto-optic device have a 30 MHz 1 ... coherent systems including compact non-coherent optical ... a relatively simple phase switching approach. ...

Science.gov (United States)

... silicon oxide (BSO), bismuth germanium oxide (BGO), and bismuth titanium oxide (BTO). These crystals are electro-optic, optically active, ...

International Nuclear Information System (INIS)

We present the results of Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) imaging of a sample of 19 high-mass passively evolving galaxies with 1.2 < z < 2, taken primarily from the Gemini Deep Deep Survey (GDDS). Around 80% of galaxies in our GDDS sample have spectra dominated by stars with ages #approx#>1 Gyr. Our rest-frame R-band images show that most of these objects have compact regular morphologies which follow the classical R "1"/"4 law. These galaxies scatter along a tight sequence in the size versus surface brightness parameter space which defines the Kormendy relation. Around one-third (3/10) of the massive red objects in the GDDS sample are extraordinarily compact, with effective radii under 1 kpc. Our NICMOS observations allow the detection of such systems more robustly than is possible with optical (rest-frame UV) data, and while similar systems have been seen at z #approx#> 2, this is ...

International Nuclear Information System (INIS)

We derive stellar masses, ages, and star formation histories (SFHs) of massive early-type galaxies in the z = 1.237 RDCS1252.9-2927 cluster and compare them with those measured in a similarly mass-selected sample of field contemporaries drawn from the Great Observatories Origin Deep Survey South Field. Robust estimates of these parameters are obtained by comparing a large grid of composite stellar population models with 8-9 band photometry in the rest-frame near-ultraviolet, optical, and IR, thus sampling the entire relevant domain of emission of the different stellar populations. Additionally, we present new, deep U-band photometry of both fields, giving access to the critical far-ultraviolet rest frame, in order to empirically constrain the dependence of the most recent star formation processes on the environment. We also analyze the morphological properties of both samples to examine the dependence of their scaling relations on their mass and environment. We ...

Science.gov (United States)

... Biomedical Engineering Optical and Photonic Materials and Devices Fundamental Optical Interactions ... of Texas Medical School OPTICAL AND PHOTONIC MATERIALS AND DEVICES Gary Bjorklund, IBM, Chair Nan ...

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... Abstract : MANY THIN FILM ACOUSTO-OPTIC INTERACTION EXPERIMENTS FOR ... CONVERTERS, AND FOR FAST SWITCHES HAVE BEEN ...

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... Acousto-optic programmable dispersive filters (AOPDF) have been developed for optical signal processing, polarization switching in lasers, and ...

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An integrated mirrorless bistable optical device based on the Mach-Zehnder interferometric optical switch has been proposed and demonstrated experimentally using a Ti:LiNbO3 waveguide. The resulting device is capable of combining more than two of them to realize multifunctional optical devices such as optical multivibrators.

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Conventional radiography has been the accepted nondestructive testing (NDT) method used for many years to either ''accent'' or ''reject'' a field weld in the pipeline industry. However, conventional radiography requires the expense of film, developing chemicals, and manpower for film development. It also normally has a delay of 2 hours or more between when the weld was radiographed and when the radiographic film of the weld is available for interpretation. Over the last few years, a newer approach to performing radiographic testing, called ''realtime'' radiography, has been used in several different types of field inspection operations. The realtime radiography system forms the image with optical imaging in lieu of photographic film. Objectives of this project were: (Task 1) Integration of realtime x-ray system ...

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This library, written in Java, supports input and output of images and metadata (labels) in the

International Nuclear Information System (INIS)

We report on the first measurements of the z-dependent evolution of electron-beam microbunching as revealed through coherent transition radiation (CTR) measurements in a visible self-amplified spontaneous emission free-electron laser experiment. The increase in microbunching was detected by tracking the growth of the visible CTR signals as generated from insertable metal mirrors/foils after each of the last three undulators. The same optical imaging diagnostics that were used to track the z-dependent intensity of the undulator radiation (UR) were also used to track the electron beam/CTR information. Angular distribution, beam size, and intensity data were obtained after each of the last three undulators in the five-undulator series, and spectral information was obtained after the last undulator. The exponential growth rate of the CTR was found to be very similar to that of the UR and consistent with simulations using the code GENESIS.

International Nuclear Information System (INIS)

The present study has examined for #alpha#/#beta#-Ti alloys the relationship between the morphology and crystallography of Widmanstaetten plates of #alpha#-Ti in colonies within a prior grain of #beta#-Ti. Thus, optical metallography, scanning electron microscopy and transmission electron microscopy have been used to characterize the morphological features of the microstructure, whereas orientation-imaging microscopy (OM) and transmission electron microscopy (TEM) have been employed to reveal crystallographic information. It has been discovered that within a prior #beta#-Ti grain, although the growth direction of the Widmanstaetten plates in given colonies may differ by large angles from #alpha#-plates in other colonies, they may exhibit very close crystallographic relationships. For example, inclined #alpha#-plates may share common basal planes and be related by a rotation of #approx#10.5 deg. about the c-axis of the crystals. This phenomenon ...

CERN Document Server

(abridged) We present a study of stellar population of LAEs at z=4.86 in GOODS-N and its flanking field. With the publicly available IRAC data in GOODS-N and further IRAC observations in the flanking fields, we select five LAEs which are not contaminated by neighboring objects in IRAC images and construct their observed SEDs with I_c, z', IRAC 3.6micron, and 4.5micron band photometry. The SEDs cover the rest-frame UV to optical wavelengths. We derive stellar masses, ages, color excesses, and star formation rates of five LAEs using SED fitting method. Assuming the constant star formation history, we find that the stellar masses range from 10^8 to $10^{10} Msun with the median value of 2.5x10^9 Msun. The derived ages range from very young ages (7.4 Myr) to 437 Myr with a median age of 25 Myr. The color excess E(B-V) are between 0.1-0.4 mag. Star formation rates are 55-209 Msun/yr. A comparison of the stellar populations is made between three LAEs ...

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A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed Tomography (X-CT) system are used to determine the flow regime, the instantaneous cross-sectional averaged void fraction, and the time averaged void fraction in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements are obtained for gas flow rates form 0.0 to 30.0 l/min. The flow regimes observed by all three measurement systems via image analysis shows that the results agree well with each other. Both the RTNR and the X-CT systems show that the time averaged and cross-sectional averaged void fraction increases with increasing superficial gas velocity. Time and cross-sectional averaged void fractions determined by the RTNR system agree within 4% with those determined by the high speed X-ray CT technique. (orig.).

CERN Document Server

We have carried out studies on the rheological properties of regenerated silk fibroin (RSF) solution using video microscopy. The degummed silk from the Bombyx mori silkworm was used to prepare RSF solution by dissolving it in calcium nitrate tetrahydrate-methanol solvent. Measurements were carried out by tracking the position of an embedded micron-sized polystyrene bead within the RSF solution through video imaging. The time dependent mean squared displacement (MSD) of the bead in solution and hence, the complex shear modulus of this solution was calculated from the bead's position information. An optical tweezer was used to transport and locate the bead at any desired site within the micro-volume of the sample, to facilitate the subsequent free-bead video analysis. We present here the results of rheological measurements of the silk polymer network in solution over a frequency range, whose upper limit is the frame capture rate of our camera, at ...

CERN Document Server

We report results from a 50 ks XMM-Newton observation of the dust-reddened broad-line quasar FTM 0830+3759 (z=0.413) selected from the FIRST/2MASS Red Quasar survey. For this AGN, a very short 9 ks Chandra exposure had suggested a feature-rich X-ray spectrum and HST images revealed a very disturbed host galaxy morphology. Contrary to classical, optically-selected quasars, the X-ray properties of red (i.e. with J-Ks> 1.7 and R-Ks> 4) broad line quasars are still quite unexplored, although there is a growing consensus that, due to moderate obscuration, these objects can offer a unique view of spectral components typically swamped by the AGN light in normal, blue quasars. The XMM-Newton observation discussed here has definitely confirmed the complexity of the X-ray spectrum revealing the presence of a cold (or mildly-ionized) absorber with Nh ~10^{22} cm^-2 along the line of sight to the nucleus and a Compton reflection component accompanied ...

International Nuclear Information System (INIS)

The present volume on energy and the environment discusses space power requirements, space power systems, space power systems hardware, space radioisotope systems, space solar arrays, space solar cells, space station power, and terrestrial applications of aerospace technology. Attention is given to NASA future space power requirements and issues, the design of a battery charger for the NASA EOS Space Platform, in situ carbon dioxide fixation on Mars, and a preliminary design update of the CRAF/Cassini Power Subsystem. Topics addressed include concentrator testing using projected images, solar power satellites and demonstraton platforms from nonterrestrial materials, a mass sensitivity analysis of lunar orbiting beam power systems, and a power-beaming-based infrastructure for space power. Also discussed are fiber-optic sensors for aerospace electrical measurements, the preliminary design of a mobile lunar power supply, advanced power systems for ...

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By both increasing the optical iris of the video camera and removing the grid in fluoroscopic procedures involved in placement of a Dubbhoff feeding tube, the radiation dose to patients and staff was reduced by five to seven times. An average expected dose to a patient of about 300 mGy per procedure was reduced by two to three times when the grid was removed and by an additional three times when an iris of increased diameter was used. Because Dobbhoff procedures do not involve obtaining a diagnosis, the image degradation was acceptable and did not affect the total exposure times or ability to conduct the procedure. With the grid out, the difference between the mean exposure times of 5.1 minutes in 96 patient studies done with a normal iris opening and 4.0 minutes in 52 studies done with an enlarged iris was not statistically significant. The importance of reducing patient dose is reinforced by the finding that one-third of the patients ...

International Nuclear Information System (INIS)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,#theta#) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

CERN Document Server

We have discovered seven type Ia cluster supernovae (SNe) in the course of the Wise Observatory Optical Transients Search in the fields of galaxy clusters with redshifts between z=0.06 and z=0.2. Two of these events, SN 1998fc in Abell 403 (z=0.10) and SN 2001al in Abell 2122/4 (z = 0.066), have no obvious hosts. Both events appear projected on the halos of the central cD galaxies, but have velocity offsets of 750-2000 km/s relative to those galaxies, suggesting they are not bound to them. We use deep Keck imaging of the locations of the two SNe to put upper limits on the luminosities of possible dwarf hosts, M_R > -14 mag for SN 1998fc and M_R > -11.8 mag for SN 2001al. The fractions of the cluster luminosities in dwarf galaxies fainter than our limits are less than 3 x 10^-3 and 3 x 10^-4, respectively. Thus, 2/7 of the SNe would be associated with less than 3 x 10^-3 of the luminosity attributed to galaxies. We argue, instead, that the ...

Energy Technology Data Exchange (ETDEWEB)

An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

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This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a ...

Science.gov (United States)

This paper describes the design of a test rig, which is used to apply a representative pressure load to a full-scale composite sandwich secondary aircraft structure. A generic panel was designed with features to represent those in the composite sandwich secondary aircraft structure. To provide full-field strain data from the panels, the test rig was designed for use with optical measurement techniques such as thermoelastic stress analysis (TSA) and digital image correlation (DIC). TSA requires a cyclic load to be applied to a structure for the measurement of the strain state; therefore, the test rig has been designed to be mounted on a standard servo-hydraulic test machine. As both TSA and DIC require an uninterrupted view of the surface of the test panel, an important consideration in the design is facilitating the optical access for the two techniques. To aid the test rig design a finite element (FE) model was produced. ...

Energy Technology Data Exchange (ETDEWEB)

During a number of years research and development projects have been made to present methods of monitoring the grate in a grate fired boiler. The monitoring is interesting in order to be able to increase efficiency, increase burn-out of ash, improve the status of emissions, improve transportation of ash and fuel through the furnace, reduce costs for operation and maintenance, handle greater loads etc. Improvement of the combustion has been concentrated to the development of the gas phase combustion. In the past few years the computer development has progressed rapidly and the use of optical monitoring methods have been made possible for monitoring grates. To analyse state of the art of optical grate monitoring systems three different methods have been used, literature search, inquiry where plant owners were asked if they have used grate monitoring systems and if so what experiences they have, and interviews with scientists and users. The ...

Science.gov (United States)

Upon illumination of an optically driven Q-switch 35 over conventional electro- optic, acousto-optic and medium located inside the laser cavity with an ...

UK PubMed Central (United Kingdom)

During formation of the optic projection in astray/robo2 mutant zebrafish, optic axons exhibit rostro-caudal pathfinding errors, ectopic midline crossing and...Full Text Available

DEFF Research Database (Denmark)

Functional magnetic resonance imaging (fMRI) in young children may provide information about the development of the visual cortex, and may have predictive value for later visual performance. The purpose of this study was to evaluate the usefulness of fMRI for examining cerebral processing of vision in very young infants and in infants with brain damage. We examined 15 preterm infants, 12 children suspected of having a cerebral visual impairment and 10 children with a normal visual system, all of whom were either spontaneously asleep or sedated with chloral hydrate. Cortical response to stroboscopic light stimulation could be demonstrated in all technically acceptable data sets from children with a post-menstrual age (PMA) of > 41 weeks, but not in younger infants. Children < 60 weeks PMA showed either a blood oxygenation level-dependent (BOLD) signal increase or decrease, while all older children showed a signal decrease. The activated cortical volumes showed ...

Science.gov (United States)

The Asarco-Mission complex (image left) is an active producer of copper and molybdenum (important in making steel and other metal alloys), ...

International Nuclear Information System (INIS)

Real-time neutron radiography (NTV) has been used for practical applications at the Kyoto University Reactor (KUR). At present, however, the direct image from the TV system is still poor in resolution and low in contrast. In this paper several image improvements are demonstrated, such as a frame summing technique, which are effective in increasing image quality in neutron radiography. Image integration before the A/D converter has a beneficial effect on image quality and the high quality image reveals details invisible in direct images, such as: small holes by a reversed image, defects in a neutron converter screen through a high quality image, a moving object in a contoured image, a slight difference between two low-contrast images by a subtraction ...

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performs Gaussian pyramid operation on an image performs expand pyramid operation on an image mosaic two images using 'reduce' and 'expand' pyramid ...

International Nuclear Information System (INIS)

This paper outlines conceptual framework for safeguards remote sensing, and suggests a strategy for overcoming the challenges to full exploitation of all types of optical satellite imagery. Since the introduction of commercial open-source high-resolution satellite imagery in 1999, it has become an important tool for verification of declarations, baseline mapping, detection and monitoring of changes and investigation of undeclared activities. Its use is still relatively restricted, but there is a growing demand for wider satellite reconnaissance support, and the Satellite Image Analysis Unit (SIAU) has recently been expanded in response. For a number of reasons, IAEA safeguards use of satellite imagery is largely based on visual interpretation by experienced image analysts of high-resolution monochromatic imagery to monitor and characterize buildings and structures on safeguards sites. The very wide range of remote sensing ...

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The first application of optical Stark modulation has been applied to measure spatially precise Stark-modulated IR absorption spectra in a flame.

UK PubMed Central (United Kingdom)

There is a requirement for a noninvasive technique to monitor stem cell differentiation. Several candidates based on optical spectroscopy are discussed in this review: Fourier transform infrared (FTIR)...Full Text Available

UK PubMed Central (United Kingdom)

Purpose. To describe the characteristics of idiopathic macular holes (MH) on optical coherence tomography (OCT) and correlate OCT with clinical assessment. Design....Full Text Available

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... a rotating mirror Q-switch or an acousto-optic Q-switch. The former ... Q-switch up to 2000 pps. The Q-switched output bean, is predominantly ...

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Jan 22, 2004 ... Training and Professional Development Leadership Development Program. GSFC Leadership Development Program Positions. Cryo-Optical ...

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We propose new method of assessment of histological images for medical diagnostics. 2-D image is preprocessed to form 1-D landscapes or 1-D signature of the image contour and then their complexity is...Full Text Available

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This paper describes Image Engine, an object-oriented, microcomputer-based, multimedia database designed to facilitate the storage and retrieval of digitized biomedical still images, video, and text...Full Text Available

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Adaptive image processing is one of the most important techniques in visual information processing, especially in early vision such as image restoration, filtering, enhancement, and segmentation. This work focuses on applications of advanced CI techniques in image processing applications

International Nuclear Information System (INIS)

A real time neutron radiography system has been developed at the University of Michigan Phoenix Memorial Laboratory (PML) and has recently been used to test the imaging capabilities of a neutron imaging device developed by Lixi, Inc. of Downers Grove, Ill. This device uses an input phosphor that is high in gadolinium to generate a light image which is then sent through an intensifier stage to provide images that can be viewed by eye, video camera, or standard 35 mm camera. It was determined that this device provides images of much higher resolution and sensitivity than those obtained with the imaging system currently being used at PML. Using computerized image enhancement techniques, the images obtained with the Lixi neutron imaging device can then be further enhanced or processed to obtain ...

International Nuclear Information System (INIS)

The suitability of MR imaging versus computerized tomography in observation of brain development disorders in children are compared. 13 refs.

International Nuclear Information System (INIS)

Certain radioiodine containing esters useful as brain imaging agents are disclosed. The formula of these compounds are presented.

International Nuclear Information System (INIS)

Certain radioiodine containing amides useful as brain imaging agents are disclosed. The compounds of the subject invention are represented by the formula.

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Described herein is an optical probe (120) for use in characterizing surface defects in wafers, such as semiconductor wafers. The optical probe (120) detects laser light reflected from the surface (124) of the wafer (106) within various ranges of angles. Characteristics of defects in the surface (124) of the wafer (106) are determined based on the amount of reflected laser light detected in each of the ranges of angles. Additionally, a wafer characterization system (100) is described that includes the described optical probe (120).

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This book examines the nonlinear optical properties of laser materials. The physical radiation effects on laser materials are also considered. Topics considered include: nonlinear optical properties; nonlinear and harmonic generation materials; two-photon absorption; nonlinear refractive index; stimulated Raman scattering; radiation damage; crystals; and glasses.

International Nuclear Information System (INIS)

In this study, a miniature fiber-optic radiation detector has been developed using a water-equivalent organic scintillator for electron beam therapy dosimetry. Usually, two kinds of light signals such as fluorescent and Cherenkov lights are generated in a fiber-optic radiation detector when a high-energy electron beam is irradiated. The fluorescent light signal is produced in the scintillator and is transmitted through a plastic optical fiber to a remote light-measuring device such as a PMT or a photodiode. The Cherenkov light could be also produced in the plastic optical fiber itself and be detected by a light-measuring device. Therefore, it could cause problems or limit the accuracy of the detection of a fluorescent light signal that is proportional to dose. The objectives of this study are to measure, characterize and eliminate Cherenkov light generated in a plastic optical fiber ...

International Nuclear Information System (INIS)

Because of limitation on neutron-incident data, it is difficult to obtain global optical model potential for neutrons. In contrast, there are some global optical model potentials for proton in detail. It is interesting to convert the proton-incident global optical potentials into neutron-incident ones. In this study we introduce (N-Z)/A dependent symmetry potential terms into the global proton-incident optical potentials, and then obtain neutron-incident ones. The neutron potentials reproduce total cross sections in an acceptable degree. However, a comparison with potentials proposed by other authors brings about a confused situation in the sign of the symmetry terms. (author).

International Nuclear Information System (INIS)

A fiber optic feedthrough module which comprises a metal sleeve, a fiber optic element extending through the sleeve in spaced relation thereto, and a tandem series of centrally-apertured mating annular sealant bodies of thermoplastic material surrounding the fiber optic element and compressed between it and the sleeve. The module is made by first providing a loose subassembly of a plurality of individual but interfitting sealant bodies on the fiber optic element and then inserting this subassembly into a metal sleeve, following by swaging the whole assembly which eliminates clearances and provides sealed interfaces between the various contacting components. (author).

Energy Technology Data Exchange (ETDEWEB)

Multi-dimensional modelling of two-phase flow requires accurate constitutive relationships for interfacial parameters such as interfacial heat transfer, void fraction distribution, interfacial area, etc. However, existing diagnostic systems for measurement of two-phase flow parameters have difficulty measuring two or three-dimensional void distributions required for determination of interfacial parameters. In this work, a Real-Time Neutron Radiography (RTNR) system is developed for non-intrusive measurement of two-phase flow parameters in nuclear fuel channels at low thermal neutron fluxes (on the order of 10{sup 6}n/cm{sup 2}-s). This advanced radiation technique has the advantage of measuring two-phase flow in 3 1/2 dimensions (x,{integral}dy,t) where the 1/2 dimension refers to an integrated or averaged space dimension. Pipe flow channels, annulus flow channels, MAPLE-type nuclear fuel flow channels, and CANDU-type nuclear fuel flow channels are investigated. Measurements of flow ...

CERN Document Server

The present research scholars are having keen interest in doing their research activities in the area of Data mining all over the world. Especially, [13]Mining Image data is the one of the essential features in this present scenario since image data plays vital role in every aspect of the system such as business for marketing, hospital for surgery, engineering for construction, Web for publication and so on. The other area in the Image mining system is the Content-Based Image Retrieval (CBIR) which performs retrieval based on the similarity defined in terms of extracted features with more objectiveness. The drawback in CBIR is the features of the query image alone are considered. Hence, a new technique called Image retrieval based on optimum clusters is proposed for improving user interaction with image retrieval systems by fully exploiting ...

Energy Technology Data Exchange (ETDEWEB)

In this work, we use lasers to enhance possibilities of laser desorption methods and to optimize coating procedure for capillary electrophoresis (CE). We use several different instrumental arrangements to characterize matrix-assisted laser desorption (MALD) at atmospheric pressure and in vacuum. In imaging mode, 488-nm argon-ion laser beam is deflected by two acousto-optic deflectors to scan plumes desorbed at atmospheric pressure via absorption. All absorbing species, including neutral molecules, are monitored. Interesting features, e.g. differences between the initial plume and subsequent plumes desorbed from the same spot, or the formation of two plumes from one laser shot are observed. Total plume absorbance can be correlated with the acoustic signal generated by the desorption event. A model equation for the plume velocity as a function of time is proposed. Alternatively, the use of a static laser beam for observation enables reliable ...

Energy Technology Data Exchange (ETDEWEB)

In portal images with high energy X-ray (10 MV), it is sometimes difficult to verify the irradiation field because of the low contrast. Especially, in the abdominal and pelvic region, the deterioration of portal image quality is remarkable. To solve this problem, we took portal images using computed radiography (FCR). Also, we develop a technique in which a copper plate (3 mm) and lead foil (0.3 mm) are closely set in the front and rear of the photostimulable phosphor plate (imaging plate), for increased energy absorption. As a result, image quality was very high and we confirmed image improvement using observer performance experiments. We made a special cassette which can closely set metallic plates to imaging plate and load FCR-7000 directly. Therefore, image process becomes simple, and suitable for routine work. In ...

International Nuclear Information System (INIS)

The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. (authors)

International Nuclear Information System (INIS)

Morusin is a pure compound isolated from root bark of Morusaustralis (Moraceae). In this study, we demonstrated that morusin significantly inhibited the growth and clonogenicity of human colorectal cancer HT-29 cells. Apoptosis induced by morusin was characterized by accumulation of cells at the sub-G_1 phase, fragmentation of DNA, and condensation of chromatin. Morusin also inhibited the phosphorylation of IKK-#alpha#, IKK-#beta# and I#kappa#B-#alpha#, increased expression of I#kappa#B-#alpha#, and suppressed nuclear translocation of NF-#kappa#B and its DNA binding activity. Dephosphorylation of NF-#kappa#B upstream regulators PI3K, Akt and PDK1 was also displayed. In addition, activation of caspase-8, change of mitochondrial membrane potential, release of cytochrome c and Smac/DIABLO, and activation of caspase-9 and -3 were observed at the early time point. Downregulation in the expression of Ku70 and XIAP was exhibited afterward. Caspase-8 ...

Energy Technology Data Exchange (ETDEWEB)

Two geriatic male rhesus monkeys were used for the radioisotope imaging in this research. Discussion of the radionuclide, materials, and method used to accomplish the neurologic examination and the results obtained, both during the procedure and confirmation of the results by necropsies were accompanied by color photos of scan images. Results were that the nuclear images provided accurate images of intracranial neoplasia.

Energy Technology Data Exchange (ETDEWEB)

This paper examines the seismic signatures of discrete, finite-length fractures, and outlines an approach for elastic, prestack reverse-time imaging of discrete fractures. The results of this study highlight the importance of incorporating fracture-generated P-S converted waves into the imaging method, and presents an alternate imaging condition that can be used in elastic reverse-time imaging when a direct wave is recorded (e.g., for crosswell and VSP acquisition geometries).

UK PubMed Central (United Kingdom)

The aim of this study was to assess the possibility of digital image analysis of pit-and-fissure discoloration in order to diagnose caries. Digital images showing pit-and-fissure discoloration in 100...Full Text Available

International Nuclear Information System (INIS)

This paper discusses the clinical application and main objective of testicular imaging. The authors present cases that represent a spectrum of the abnormalities which might be detected by testicular imaging, with special attention given to testicular torsion and the acute diseases which may mimic it clinically. Accuracy of the test is noted.

UK PubMed Central (United Kingdom)

PurposeAuto-propagation of anatomical region-of-interests (ROIs) from the planning CT to daily CT is an essential step in image-guided adaptive radiotherapy. The...Full Text Available

UK PubMed Central (United Kingdom)

Multimodality imaging with PET/CT and SPECT/CT has become commonplace in clinical practice and in preclinical and basic medical research. Do other combinations of imaging modalities have a similar...Full Text Available

UK PubMed Central (United Kingdom)

Epifluorescence images of Ca2+ transients elicited by electrical stimulation of single skeletal muscle fibers were studied with fast imaging techniques that take advantage of the large fluorescence...Full Text Available

UK PubMed Central (United Kingdom)

The use of digital wound images would allow remote consultation between patients, physicians, or other caregivers over the Internet. To evaluate the efficacy and validity of digital images for assessment...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Image registrations that are based on similarity measures simply adjust the parameters of an appropriate spatial transformation model until the similarity measure reaches an optimum. The numerous similarity measures that have been proposed in the past are differently sensitive to imaging modality, image content and differences in the image content, selection of the floating and target image, partial image overlap, etc. In this paper, we evaluate and compare 12 similarity measures for the rigid registration. To study the impact of different imaging modalities on the behavior of similarity measures, we have used 16 CT/MR and 6 PET/MR image pairs with known 'gold standard' registrations. The results for the PET/MR registration and for the registration of CT to both rectified and unrectified MR ...

International Nuclear Information System (INIS)

In portal images with high energy X-ray (10 MV), it is sometimes difficult to verify the irradiation field because of the low contrast. Especially, in the abdominal and pelvic region, the deterioration of portal image quality is remarkable. To solve this problem, we took portal images using computed radiography (FCR). Also, we develop a technique in which a copper plate (3 mm) and lead foil (0.3 mm) are closely set in the front and rear of the photostimulable phosphor plate (imaging plate), for increased energy absorption. As a result, image quality was very high and we confirmed image improvement using observer performance experiments. We made a special cassette which can closely set metallic plates to imaging plate and load FCR-7000 directly. Therefore, image process becomes simple, and suitable for routine work. In ...

UK PubMed Central (United Kingdom)

Purpose: Reverse helical cone-beam computed tomography (CBCT) is a scanning configuration for potential applications in image-guided radiation therapy in which an accurate anatomic image...Full Text Available

UK PubMed Central (United Kingdom)

In a new approach to medical computer based education (CBE) students at several U.S. and Canadian health professions schools have been using an optical videodisc under computer control to study basic...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Optical absorptance spectra of A-15 compounds were taken using a calorimetric technique in the range 0.2 eV to 4.0 eV. Thermomodulation spectra were taken on several A-15 sputtered films.

UK PubMed Central (United Kingdom)

The purpose of this study was to determine the thickness of the macula and the retinal nerve fiber layer (RNFL) in Japanese subjects by Stratus optical coherence tomography (OCT), and to compare the...Full Text Available

UK PubMed Central (United Kingdom)

The utility of a two-photon optical fiber fluorescence probe (TPOFF) for sensing and quantifying tumor fluorescent signals was tested in vivo. Xenograft tumors were developed in athymic mice using MCA207...Full Text Available

UK PubMed Central (United Kingdom)

We present a method to make phantoms of coronary arteries for intravascular optical coherence tomography (IV-OCT). The phantoms provide a calibrated OCT response similar to the layered structure of...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The central nervous system is involved in 10-20% of cases in Lyme disease. The neurological symptoms, time course of the disease and imaging findings are multifaceted. We report two patients with cervical radiculitis. Magnetic resonance imaging revealed strong enhancement of the cervical nerve roots on contrast-enhanced T1-weighted images. These imaging patterns of borrelia-associated radiculitis have not been reported before. Knowledge of these imaging features may help to diagnose neuroborreliosis, which presents with non-specific symptoms. (orig.)

Science.gov (United States)

... Tunable semiconductor lasers are essential components for links employing optical frequency modulation (OFM) for enhanced dynamic range or ...

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

Science.gov (United States)

... Abstract : A COMMERCIALLY AVAILABLE CAMOO4 TUNABLE ACOUSTO- OPTIC FILTER HAS BEEN ... OF THE FILTER CAN BE SWITCHED IN 20 ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

... and flashtube. Unfortunately, we had insufficient laser intensity to use the harmonic from a KDP crystal as a monitor. This ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This book describes the uses, coatings, and fabrication of laser materials. Topics considered include: optical waveguide materials; optical storage materials; holographic recording materials; phase conjunction materials; holographic recording materials; phase conjunction materials; laser crystals; laser glasses; quantum counter materials; thin films and coatings; multilayer dielectric coatings; graded-index surfaces and films; optical materials fabrication; fabrication techniques; fabrication procedures for specific materials.

Science.gov (United States)

Aug 25, 2004 ... The Tropical Rainfall Measuring Mission or TRMM satellite provided this image of Typhoon Aere over the western Philippine Sea as it was ...

UK PubMed Central (United Kingdom)

Abstract The authors provide a survey of how images are used in radiation therapy to improve the precision of radiation therapy plans, and delivery of radiation treatment. In contrast...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A method of increasing information content for content-based image retrieval (CBIR) systems includes the steps of providing a CBIR database, the database having an index for a plurality of stored digital images using a plurality of feature vectors, the feature vectors corresponding to distinct descriptive characteristics of the images. A visual similarity parameter value is calculated based on a degree of visual similarity between features vectors of an incoming image being considered for entry into the database and feature vectors associated with a most similar of the stored images. Based on said visual similarity parameter value it is determined whether to store or how long to store the feature vectors associated with the incoming image in the database.

Energy Technology Data Exchange (ETDEWEB)

This paper presents two imaging methods by using cross correlation. The one method images the subsurface by cross-correlation of the observed data and partial derivative seismograms calculated for a guessed model. The other method images the interface by use of cross-correlation of the virtual sources and the back propagated wave fields calculated from the observed data. Experimental tests show that both methods image subsurface interfaces well even if the guessed model is different from the true one. These imaging methods are reverse time migration that we perform cross-correlation as an imaging condition and have an advantage, as compared to conventional waveform inversion method, that images subsurface structure without iterative perturbation of the assumed model. (author). 18 refs., 15 figs.

UK PubMed Central (United Kingdom)

Over the past decade, dramatic increases in computational power and improvement in image analysis algorithms have allowed the development of powerful computer-assisted analytical approaches...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Using a sensitive optical wavelength modulation technique the surface-plasmon excited on a gold grating surface immersed in sulfuric acid is studied at the same time as cyclic voltammetry is undertaken. Because of the optical sensitivity of the modulation technique significant optical effects are observed at potentials well below those at which any gross oxidation effects occur.

Energy Technology Data Exchange (ETDEWEB)

A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field.

CERN Document Server

We propose a scheme able to generate stationary continuous variable entanglement between an optical and a microwave cavity mode by means of their common interaction with a micro-mechanical resonator. We show that when both cavities are intensely driven one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, optical-microwave entanglement is efficiently generated at the expense of microwave-mechanical and opto-mechanical entanglement.

Energy Technology Data Exchange (ETDEWEB)

Digital optical processing (DOP) was conceived to encompass the advantages of both electronic and optical processors, which are parallelism, flexibility, and high accuracy. The authors discuss the concept of parallelism, how it applies to DOP differently than to electronic parallel processing, and other potential advantages in using DOP. A PLZT memory device is described which can perform a series of logic or memory operations. From several of these PLZT devices a DOP is constructed to illustrate some of its programmability features.

CERN Document Server

Ultra-high resolution radiographs can be obtained using synchrotron X-rays. A collaboration team consisting of K-JIST, POSTECH and YUMC has recently commissioned a new beamline (5C1) at Pohang Light Source (PLS) in Korea for medical applications using phase contrast radiology. Relatively simple image acquisition systems were set up on 5C1 beamline, and imaging studies were performed for resolution test patterns, mammographic phantom, and animals. Resolution test patterns and mammographic phantom images showed much better image resolution and quality with the 5C1 imaging system than the mammography system. Both fish and mouse images with 5C1 imaging system also showed much better image resolution with great details of organs and anatomy compared to those obtained with a conventional mammography system. A simple and ...

International Nuclear Information System (INIS)

The authors describe the application of an approximate fuzzy C-means (AFCM) clustering algorithm as a data dimension reduction approach to medical magnetic resonance images (MRI). Image data consisted of one T1-weighted, two T2-weighted, and one T2*-weighted (magnetic susceptibility) image for each cranial study and a matrix of 10 images generated from 10 combinations of TE and TR for each body lymphoma study. All images were obtained with a 1.5 Tesla imaging system (GE Signa). Analyses were performed on over 100 MR image sets with a variety of pathologies. The cluster analysis was operated in an unsupervised mode and computational overhead was minimized by utilizing a table look-up approach without adversely affecting accuracy. Image data were first segmented into 2 coarse clusters, each of which was then subdivided ...

British Library Electronic Table of Contents (United Kingdom)

Plasma polymerization of aniline is carried out in a radiofrequency plasma reactor and the effect of polymerization time is examined in the structural, optical and optoelectronic properties of deposited films. Conjugated structures of polyaniline like films are obtained with unique and broad optical absorption band in the ultraviolet and entire visible region. The width of the absorption band increases and hence the optical band gap decreases with polymerization time. The optical constants are extracted by Swanepoel method and the optical dispersion parameters are determined by employing the Wemple-DiDomenico single oscillator model. The films exhibit similar thermal stability in air and argon atmosphere in the region of interest for optoelectronic applications. The photoluminescence study...

British Library Electronic Table of Contents (United Kingdom)

Until recently, the wavelength-division-multiplexed (WDM) transmission system has reached record capacities and distances due to innovations such as FEC (Forward Error Correction), distributed Raman amplification, new transmission fiber and advanced optical format. Optical-communication systems exclusively employed conventional On-Off Keying signals in either Non-Return-To-Zero (NRZ) or Return-To-Zero (RZ) format. Recently a number of advanced modulation formats have attracted attention. Some of these formats carry information through On-Off-Keying but also modulate the optical phase in order to enhance the robustness of signal to chromatic dispersion, optical filtering and non-linearities. Through extensive sets of simulation results, we showed that it is possible to replace a channel wit...

Energy Technology Data Exchange (ETDEWEB)

We review the recent development of bendable x-ray optics used for focusing of beams of soft and hard x-rays at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory and at the Linac Coherent Light Source (LCLS) x-ray free electron laser (FEL) at the Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory. For simultaneous focusing in the tangential and sagittal directions, two elliptically cylindrical reflecting elements, a Kirkpatrick-Baez (KB) pair, are used. Because fabrication of elliptical surfaces is complicated, the cost of directly fabricated tangential elliptical cylinders is often prohibitive. Moreover, such optics cannot be easily readjusted for use in multiple, different experimental arrangements, e.g. at different focal distances. This is in contrast to flat optics that are simpler to manufacture and easier to measure by conventional interferometry. The tangential figure of ...

KoreaScience (Korea)

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CERN Document Server

We investigate theoretically subwavelength imaging by acoustic metamaterial slabs immersed in the liquid matrix. A near-field subwavelength image formed by evanescent waves is achieved by a designed metamaterial slab with negative mass density and positive modulus. A subwavelength real image is achieved by a designed metamaterial slab with simultaneously negative mass density and modulus. These results are expected to shed some lights on designing novel devices of acoustic metamaterials.

International Nuclear Information System (INIS)

Brief item.

International Nuclear Information System (INIS)

X-ray imaging is a very useful plasma diagnostic method. A theoretical analysis of the x-ray phase imaging in the method based on Fresnel diffraction is given. The authors show it is a linear band pass filter, a property suit for Rayleigh-Taylor (R-T) instability measurement. The evaluation permits the possibility of R-T instability measurement in x-ray phase imaging

Norwegian Open Research Archives (NORA)

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KoreaScience (Korea)

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KoreaScience (Korea)

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