Rates for parallax-shifted microlensing events from ground-based observations of the galactic bulge

International Nuclear Information System (INIS)

Buchalter, A.; Kamionkowski, M.

1997-01-01

The parallax effect in ground-based microlensing (ML) observations consists of a distortion to the standard ML light curve arising from the Earth's orbital motion. This can be used to partially remove the degeneracy among the system parameters in the event timescale, t 0 . In most cases, the resolution in current ML surveys is not accurate enough to observe this effect, but parallax could conceivably be detected with frequent follow-up observations of ML events in progress, providing the photometric errors are small enough. We calculate the expected fraction of ML events where the shape distortions will be observable by such follow-up observations, adopting Galactic models for the lens and source distributions that are consistent with observed microlensing timescale distributions. We study the dependence of the rates for parallax-shifted events on the frequency of follow-up observations and on the precision of the photometry. For example, we find that for hourly observations with typical photometric errors of 0.01 mag, 6% of events where the lens is in the bulge, and 31% of events where the lens is in the disk (or ∼10% of events overall), will give rise to a measurable parallax shift at the 95% confidence level. These fractions may be increased by improved photometric accuracy and increased sampling frequency. While long-duration events are favored, the surveys would be effective in picking out such distortions in events with timescales as low as t 0 ∼20 days. We study the dependence of these fractions on the assumed disk mass function and find that a higher parallax incidence is favored by mass functions with higher mean masses. Parallax measurements yield the reduced transverse speed, v, which gives both the relative transverse speed and lens mass as a function of distance. We give examples of the accuracies with which v may be measured in typical parallax events. (Abstract Truncated)

An International Parallax Campaign to Measure Distance to the Moon and Mars

Science.gov (United States)

Cenadelli, D.; Zeni, M.; Bernagozzi, A.; Calcidese, P.; Ferreira, L.; Hoang, C.; Rijsdijk, C.

2009-01-01

Trigonometric parallax is a powerful method to work out the distance of celestial bodies, and it was used in the past to measure the distance of the Moon, Venus, Mars and nearby stars. We set up an observation campaign for high school and undergraduate students with the purpose to measure both the Moon's and Mars' parallax. To have a large enough…

Analysis of the diffraction effects for a multi-view autostereoscopic three-dimensional display system based on shutter parallax barriers with full resolution

Science.gov (United States)

Meng, Yang; Yu, Zhongyuan; Jia, Fangda; Zhang, Chunyu; Wang, Ye; Liu, Yumin; Ye, Han; Chen, Laurence Lujun

2017-10-01

A multi-view autostereoscopic three-dimensional (3D) system is built by using a 2D display screen and a customized parallax-barrier shutter (PBS) screen. The shutter screen is controlled dynamically by address driving matrix circuit and it is placed in front of the display screen at a certain location. The system could achieve densest viewpoints due to its specially optical and geometric design which is based on concept of "eye space". The resolution of 3D imaging is not reduced compared to 2D mode by using limited time division multiplexing technology. The diffraction effects may play an important role in 3D display imaging quality, especially when applied to small screen, such as iPhone screen etc. For small screen, diffraction effects may contribute crosstalk between binocular views, image brightness uniformity etc. Therefore, diffraction effects are analyzed and considered in a one-dimensional shutter screen model of the 3D display, in which the numerical simulation of light from display pixels on display screen through parallax barrier slits to each viewing zone in eye space, is performed. The simulation results provide guidance for criteria screen size over which the impact of diffraction effects are ignorable, and below which diffraction effects must be taken into account. Finally, the simulation results are compared to the corresponding experimental measurements and observation with discussion.

OGLE-2012-bLG-0950Lb: the First Planet Mass Measurement From Only Microlens Parallax and Lens Flux

Science.gov (United States)

Koshimoto, N.; Udalski, A.; Beaulieu, J. P.; Sumi, T.; Bennett, D. P.; Bond, I. A.; Rattenbury, N.; Fukui, A.; Bhattacharya, A.; Suzuki, D.

2016-01-01

We report the discovery of a microlensing planet OGLE-2012-BLG-0950Lb with a planet/host mass ratio Periapsis Approx. = 2 x10(exp. -4). A long term distortion detected in both MOA and OGLE light curve can be explained by themicrolens parallax due to the Earths orbital motion around the Sun. Although the finite source effect is not detected, we obtain the lens flux by the high resolution Keck AO observation. Combining the microlens parallax and the lens flux reveal the nature of the lens: a planet with mass of M(sub p) = 35(+17/-)M compared to Earth is orbiting around an M-dwarf with mass of M(sub host) = 0.56(+0.12/-0.16) M compared to the Sun with a planet-host projected separation of r1 = 2.7(+0.6/-0.7) au located at Luminosity Distance = 3.0(+0.8/-1.1) kpc from us. This is the first mass measurement from only microlens parallax and the lens flux without the finite source effect. In the coming space observation-era with Spitzer, K2, Euclid, and WFIRST, we expect many such events for which we will not be able to measure any finite source effect. This work demonstrates an ability of mass measurements in such events.

Parallax handling of image stitching using dominant-plane homography

Science.gov (United States)

Pang, Zhaofeng; Li, Cheng; Zhao, Baojun; Tang, Linbo

2015-10-01

In this paper, we present a novel image stitching method to handle parallax in practical application. For images with significant amount of parallax, the more effective approach is to align roughly and globally the overlapping regions and then apply a seam-cutting method to composite naturally stitched images. It is well known that images can be modeled by various planes result from the projective parallax under non-ideal imaging condition. The dominant-plane homography has important advantages of warping an image globally and avoiding some local distortions. The proposed method primarily addresses large parallax problem through two steps: (1) selecting matching point pairs located on the dominant plane, by clustering matching correspondences and then measuring the cost of each cluster; and (2) in order to obtain a plausible seam, edge maps of overlapped area incorporation arithmetic is adopted to modify the standard seam-cutting method. Furthermore, our approach is demonstrated to achieve reliable performance of handling parallax through a mass of experimental comparisons with state-of-the-art methods.

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

Energy Technology Data Exchange (ETDEWEB)

Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

2014-05-15

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

International Nuclear Information System (INIS)

Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

2014-01-01

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

Isotope specific resolution recovery image reconstruction in high resolution PET imaging.

Science.gov (United States)

Kotasidis, Fotis A; Angelis, Georgios I; Anton-Rodriguez, Jose; Matthews, Julian C; Reader, Andrew J; Zaidi, Habib

2014-05-01

Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The

Fall speed measurement and high-resolution multi-angle photography of hydrometeors in free fall

OpenAIRE

T. J. Garrett; C. Fallgatter; K. Shkurko; D. Howlett

2012-01-01

We describe here a new instrument for imaging hydrometeors in free fall. The Multi-Angle Snowflake Camera (MASC) captures high-resolution photographs of hydrometeors from three angles while simultaneously measuring their fall speed. Based on the stereoscopic photographs captured over the two months of continuous measurements obtained at a high altitude location within the Wasatch Front in Utah, we derive statistics for fall speed, hydrometeor size, shape, orientation and asp...

Possible Relativistic Definitions of Parallax, Proper Motion and Radial Velocity

National Research Council Canada - National Science Library

Klioner, S

2000-01-01

.... In this paper, the authors briefly describe a relativistic model of space-based optical positional observations valid at a high level of accuracy, and suggest definitions of parallax, proper motion...

FTIR free-jet set-up for the high resolution spectroscopic investigation of condensable species

Science.gov (United States)

Georges, R.; Bonnamy, A.; Benidar, A.; Decroi, M.; Boissoles, J.

2002-05-01

An existing experimental set-up combining Fourier transform infrared (FTIR) spectroscopy and free-jet cooling has been modified significantly to allow high resolution studies of the spectrum of monomer species which are liquid under standard conditions. Evaporation of the liquid samples is controlled by a condenser apparatus which is described. A supersonic planar expansion issuing from a narrow aperture is preferred for its very high cooling rate. Such an expansion, probed with a pitot tube, has a zone of limited temperature gradient close to the nozzle exit. The continuum isentropic model appears well suited to describing the thermodynamic properties of the flow up to a high number of nozzle diameters downstream. High resolution spectra of benzene and methanol have been recorded in the 3 µm wavelength range, and their analysis demonstrates a well defined rotational temperature in the 20-25 K range.

Accurate Mass Measurements for Planetary Microlensing Events Using High Angular Resolution Observations

Directory of Open Access Journals (Sweden)

Jean-Philippe Beaulieu

2018-04-01

Full Text Available The microlensing technique is a unique method to hunt for cold planets over a range of mass and separation, orbiting all varieties of host stars in the disk of our galaxy. It provides precise mass-ratio and projected separations in units of the Einstein ring radius. In order to obtain the physical parameters (mass, distance, orbital separation of the system, it is necessary to combine the result of light curve modeling with lens mass-distance relations and/or perform a Bayesian analysis with a galactic model. A first mass-distance relation could be obtained from a constraint on the Einstein ring radius if the crossing time of the source over the caustic is measured. It could then be supplemented by secondary constraints such as parallax measurements, ideally by using coinciding ground and space-born observations. These are still subject to degeneracies, like the orbital motion of the lens. A third mass-distance relation can be obtained thanks to constraints on the lens luminosity using high angular resolution observations with 8 m class telescopes or the Hubble Space Telescope. The latter route, although quite inexpensive in telescope time is very effective. If we have to rely heavily on Bayesian analysis and limited constraints on mass-distance relations, the physical parameters are determined to 30–40% typically. In a handful of cases, ground-space parallax is a powerful route to get stronger constraint on masses. High angular resolution observations will be able to constrain the luminosity of the lenses in the majority of the cases, and in favorable circumstances it is possible to derive physical parameters to 10% or better. Moreover, these constraints will be obtained in most of the planets to be discovered by the Euclid and WFIRST satellites. We describe here the state-of-the-art approaches to measure lens masses and distances with an emphasis on high angular resolution observations. We will discuss the challenges, recent results and

Secular Extragalactic Parallax and Geometric Distances with Gaia Proper Motions

Science.gov (United States)

Paine, Jennie; Darling, Jeremiah K.

2018-06-01

The motion of the Solar System with respect to the cosmic microwave background (CMB) rest frame creates a well measured dipole in the CMB, which corresponds to a linear solar velocity of about 78 AU/yr. This motion causes relatively nearby extragalactic objects to appear to move compared to more distant objects, an effect that can be measured in the proper motions of nearby galaxies. An object at 1 Mpc and perpendicular to the CMB apex will exhibit a secular parallax, observed as a proper motion, of 78 µas/yr. The relatively large peculiar motions of galaxies make the detection of secular parallax challenging for individual objects. Instead, a statistical parallax measurement can be made for a sample of objects with proper motions, where the global parallax signal is modeled as an E-mode dipole that diminishes linearly with distance. We present preliminary results of applying this model to a sample of nearby galaxies with Gaia proper motions to detect the statistical secular parallax signal. The statistical measurement can be used to calibrate the canonical cosmological “distance ladder.”

Applications of high-resolution spatial discretization scheme and Jacobian-free Newton–Krylov method in two-phase flow problems

International Nuclear Information System (INIS)

Zou, Ling; Zhao, Haihua; Zhang, Hongbin

2015-01-01

Highlights: • Using high-resolution spatial scheme in solving two-phase flow problems. • Fully implicit time integrations scheme. • Jacobian-free Newton–Krylov method. • Analytical solution for two-phase water faucet problem. - Abstract: The majority of the existing reactor system analysis codes were developed using low-order numerical schemes in both space and time. In many nuclear thermal–hydraulics applications, it is desirable to use higher-order numerical schemes to reduce numerical errors. High-resolution spatial discretization schemes provide high order spatial accuracy in smooth regions and capture sharp spatial discontinuity without nonphysical spatial oscillations. In this work, we adapted an existing high-resolution spatial discretization scheme on staggered grids in two-phase flow applications. Fully implicit time integration schemes were also implemented to reduce numerical errors from operator-splitting types of time integration schemes. The resulting nonlinear system has been successfully solved using the Jacobian-free Newton–Krylov (JFNK) method. The high-resolution spatial discretization and high-order fully implicit time integration numerical schemes were tested and numerically verified for several two-phase test problems, including a two-phase advection problem, a two-phase advection with phase appearance/disappearance problem, and the water faucet problem. Numerical results clearly demonstrated the advantages of using such high-resolution spatial and high-order temporal numerical schemes to significantly reduce numerical diffusion and therefore improve accuracy. Our study also demonstrated that the JFNK method is stable and robust in solving two-phase flow problems, even when phase appearance/disappearance exists

Three-dimensional visualization of geographical terrain data using temporal parallax difference induction

Science.gov (United States)

Mayhew, Christopher A.; Mayhew, Craig M.

2009-02-01

Vision III Imaging, Inc. (the Company) has developed Parallax Image Display (PIDTM) software tools to critically align and display aerial images with parallax differences. Terrain features are rendered obvious to the viewer when critically aligned images are presented alternately at 4.3 Hz. The recent inclusion of digital elevation models in geographic data browsers now allows true three-dimensional parallax to be acquired from virtual globe programs like Google Earth. The authors have successfully developed PID methods and code that allow three-dimensional geographical terrain data to be visualized using temporal parallax differences.

Motion robust high resolution 3D free-breathing pulmonary MRI using dynamic 3D image self-navigator.

Science.gov (United States)

Jiang, Wenwen; Ong, Frank; Johnson, Kevin M; Nagle, Scott K; Hope, Thomas A; Lustig, Michael; Larson, Peder E Z

2018-06-01

To achieve motion robust high resolution 3D free-breathing pulmonary MRI utilizing a novel dynamic 3D image navigator derived directly from imaging data. Five-minute free-breathing scans were acquired with a 3D ultrashort echo time (UTE) sequence with 1.25 mm isotropic resolution. From this data, dynamic 3D self-navigating images were reconstructed under locally low rank (LLR) constraints and used for motion compensation with one of two methods: a soft-gating technique to penalize the respiratory motion induced data inconsistency, and a respiratory motion-resolved technique to provide images of all respiratory motion states. Respiratory motion estimation derived from the proposed dynamic 3D self-navigator of 7.5 mm isotropic reconstruction resolution and a temporal resolution of 300 ms was successful for estimating complex respiratory motion patterns. This estimation improved image quality compared to respiratory belt and DC-based navigators. Respiratory motion compensation with soft-gating and respiratory motion-resolved techniques provided good image quality from highly undersampled data in volunteers and clinical patients. An optimized 3D UTE sequence combined with the proposed reconstruction methods can provide high-resolution motion robust pulmonary MRI. Feasibility was shown in patients who had irregular breathing patterns in which our approach could depict clinically relevant pulmonary pathologies. Magn Reson Med 79:2954-2967, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

SPACE-BASED MICROLENS PARALLAX OBSERVATION AS A WAY TO RESOLVE THE SEVERE DEGENERACY BETWEEN MICROLENS-PARALLAX AND LENS-ORBITAL EFFECTS

Energy Technology Data Exchange (ETDEWEB)

Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Soszyński, I.; Skowron, J.; Mróz, P.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Wyrzykowski, Ł.; Pawlak, M. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Lee, C.-U.; Gould, A.; Chung, S.-J.; Kim, S.-L.; Cha, S.-M. [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Bozza, V. [Dipartimento di Fisica “E. R. Caianiello”, Uńiversitá di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (Italy); Albrow, M. D. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch 8020 (New Zealand); Jung, Y. K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138 (United States); Collaboration: OGLE Collaboration; KMTNet Collaboration; and others

2016-08-10

In this paper, we demonstrate the severity of the degeneracy between the microlens-parallax and lens-orbital effects by presenting the analysis of the gravitational binary-lens event OGLE-2015-BLG-0768. Despite the obvious deviation from the model based on the linear observer motion and the static binary, it is found that the residual can be almost equally well explained by either the parallactic motion of the Earth or the rotation of the binary-lens axis, resulting in the severe degeneracy between the two effects. We show that the degeneracy can be readily resolved with the additional data provided by space-based microlens parallax observations. By enabling us to distinguish between the two higher-order effects, space-based microlens parallax observations will not only make it possible to accurately determine the physical lens parameters but also to further constrain the orbital parameters of binary lenses.

Balanced steady-state free precession with parallel imaging gives distortion-free fMRI with high temporal resolution.

Science.gov (United States)

Chappell, Michael; Håberg, Asta K; Kristoffersen, Anders

2011-01-01

Research on the functions of the human brain requires that functional magnetic resonance imaging (MRI) moves towards producing images with less distortion and higher temporal and spatial resolution. This study compares passband balanced steady-state free precession (bSSFP) acquisitions with and without parallel imaging (PI) to investigate whether combining PI with this pulse sequence is a viable option for functional MRI. Such a novel combination has the potential to offer the distortion-free advantages of bSSFP with the reduced acquisition time of PI. Scans were done on a Philips 3T Intera, using the installed bSSFP pulse sequence, both with and without the sensitivity encoding (SENSE) PI option. The task was a visual flashing checkerboard, and the viewing window covered the visual cortex. Sensitivity comparisons with and without PI were done using the same manually drawn region of interest for each time course of the subject, and comparing the z-score summary statistics: number of voxels with z>2.3, the mean of those voxels, their 90th percentile and their maximum value. We show that PI greatly improves the temporal resolution in bSSFP, reducing the volume acquisition time by more than half in this study to 0.67 s with 3-mm isotropic voxels. At the same time, a statistically significant increase was found for the maximum z-score using bSSFP with PI as compared to without it (P=.02). This improvement can be understood in terms of physiological noise, as demonstrated by noise measurements. This produces observed increases in the overall temporal signal to noise of the functional time series, giving greater sensitivity to functional activations with PI. This study demonstrates for the first time the possibility of combining PI with bSSFP to achieve distortion-free functional images without loss of sensitivity and with high temporal resolution. Copyright © 2011 Elsevier Inc. All rights reserved.

Integration time for the perception of depth from motion parallax.

Science.gov (United States)

Nawrot, Mark; Stroyan, Keith

2012-04-15

The perception of depth from relative motion is believed to be a slow process that "builds-up" over a period of observation. However, in the case of motion parallax, the potential accuracy of the depth estimate suffers as the observer translates during the viewing period. Our recent quantitative model for the perception of depth from motion parallax proposes that relative object depth (d) can be determined from retinal image motion (dθ/dt), pursuit eye movement (dα/dt), and fixation distance (f) by the formula: d/f≈dθ/dα. Given the model's dynamics, it is important to know the integration time required by the visual system to recover dα and dθ, and then estimate d. Knowing the minimum integration time reveals the incumbent error in this process. A depth-phase discrimination task was used to determine the time necessary to perceive depth-sign from motion parallax. Observers remained stationary and viewed a briefly translating random-dot motion parallax stimulus. Stimulus duration varied between trials. Fixation on the translating stimulus was monitored and enforced with an eye-tracker. The study found that relative depth discrimination can be performed with presentations as brief as 16.6 ms, with only two stimulus frames providing both retinal image motion and the stimulus window motion for pursuit (mean range=16.6-33.2 ms). This was found for conditions in which, prior to stimulus presentation, the eye was engaged in ongoing pursuit or the eye was stationary. A large high-contrast masking stimulus disrupted depth-discrimination for stimulus presentations less than 70-75 ms in both pursuit and stationary conditions. This interval might be linked to ocular-following response eye-movement latencies. We conclude that neural mechanisms serving depth from motion parallax generate a depth estimate much more quickly than previously believed. We propose that additional sluggishness might be due to the visual system's attempt to determine the maximum dθ/dα ratio

Cut-free LK quasi-polynomially simulates resolution

OpenAIRE

Arai, Noriko

1998-01-01

In this paper, the relative efficiency of two propositional systems is studied: resolution and cut-free LK in DAG. We give an upper bound for translation of resolution refutation to cut-free LK proofs. The best upper bound known was 2.

Optical layout of autostereoscopic display that simultaneously reproduces two views each with full-screen resolution.

Science.gov (United States)

Ezhov, Vasily

2014-12-20

Traditional 60 Hz autostereoscopic displays with static amplitude parallax barriers have a half of full-screen resolution in each of the two displayed views of a 3D scene. The known 120 Hz autostereoscopic displays with dynamic amplitude parallax barriers have full-screen resolution but are characterized by essential light intensity losses and crosstalk in each of displayed views. The recently proposed autostereoscopic displays with simultaneous reproducing two image elements in each display pixel and with a polarization parallax barrier have full-screen resolution. However, the existing optical layout of these displays does not provide optimum operating conditions for the polarization parallax barrier creating a tendency to degrade the contrast and color characteristics. This paper presents a new optical layout characterized by the rearrangement of optical components of the previous layout. In this approach, the highlighted problems are addressed without any trade-offs. Through informal subjective visual tests, this proposal is found to provide good contrast and good color balance in the output image.

Hubble Space Telescope Trigonometric Parallax of Polaris B, Companion of the Nearest Cepheid

Science.gov (United States)

Bond, Howard E.; Nelan, Edmund P.; Remage Evans, Nancy; Schaefer, Gail H.; Harmer, Dianne

2018-01-01

Polaris, the nearest and brightest Cepheid, is a potential anchor point for the Leavitt period–luminosity relation. However, its distance is a matter of contention, with recent advocacy for a parallax of ∼10 mas, in contrast with the Hipparcos measurement of 7.54 ± 0.11 mas. We report an independent trigonometric parallax determination, using the Fine Guidance Sensors (FGS) on the Hubble Space Telescope. Polaris itself is too bright for FGS, so we measured its eighth-magnitude companion Polaris B, relative to a network of background reference stars. We converted the FGS relative parallax to absolute, using estimated distances to the reference stars from ground-based photometry and spectral classification. Our result, 6.26 ± 0.24 mas, is even smaller than that found by Hipparcos. We note other objects for which Hipparcos appears to have overestimated parallaxes, including the well-established case of the Pleiades. We consider possible sources of systematic error in the FGS parallax, but find no evidence they are significant. If our “long” distance is correct, the high luminosity of Polaris indicates that it is pulsating in the second overtone of its fundamental mode. Our results raise several puzzles, including a long pulsation period for Polaris compared to second-overtone pulsators in the Magellanic Clouds, and a conflict between the isochrone age of Polaris B (∼2.1 Gyr) and the much younger age of Polaris A. We discuss possibilities that B is not a physical companion of A, in spite of the strong evidence that it is, or that one of the stars is a merger remnant. These issues may be resolved when Gaia provides parallaxes for both stars. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

International Nuclear Information System (INIS)

Wu, Pei-Hsin; Chung, Hsiao-Wen; Tsai, Ping-Huei; Wu, Ming-Long; Chuang, Tzu-Chao; Shih, Yi-Yu; Huang, Teng-Yi

2013-01-01

Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm 3 achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm 3 voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm 3 to 0.43 × 0.43 × 2 mm 3 has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain

High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

Energy Technology Data Exchange (ETDEWEB)

Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

2013-12-15

Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

Accuracy analysis of exterior orientation elements on vertical parallax in POS-supported aerial photogrammetry

Science.gov (United States)

Wu, Zhenli; Yuan, Xiuxiao

2009-10-01

This paper analyzes the effect of exterior orientation elements on vertical parallax, especially using the orientation parameters of aerial images obtained by a POS (Positioning and Orientation System) after calibration. Firstly, based on the theory of analytical relative orientation of consecutive photo connection, the exterior orientation elements can be easily translated to relative orientation elements. Then, the formula of vertical parallax can be deduced. The results of vertical parallax in left image space coordinate system are compared with the results calculated in the image coordinate system which are parallel to those of the object coordinate system. The validity and feasibility of the mathematical model are tested using two sets of actual data at different images scales. Finally, the differences between the effects of exterior orientation parameters on vertical parallax are compared using exterior orientation parameters obtained by traditional bundle block adjustment and by a POS after calibrated. And how the single element of exterior orientation effected on vertical parallax and how they worked together are analyzed. The empirical results indicate that the effects of different elements of exterior orientation on vertical parallax are different, all exterior orientation parameters can be affected by each other, so the overall effect of vertical parallax accuracy can be restricted by all exterior orientation parameters.

Parallax adjustment algorithm based on Susan-Zernike moments

Science.gov (United States)

Deng, Yan; Zhang, Kun; Shen, Xiaoqin; Zhang, Huiyun

2018-02-01

Precise parallax detection through definition evaluation and the adjustment of the assembly position of the objective lens or the reticle are important means of eliminating the parallax of the telescope system, so that the imaging screen and the reticle are clearly focused at the same time. An adaptive definition evaluation function based on Susan-Zernike moments is proposed. First, the image is preprocessed by the Susan operator to find the potential boundary edge. Then, the Zernike moments operator is used to determine the exact region of the reticle line with sub-pixel accuracy. The image definition is evaluated only in this related area. The evaluation function consists of the gradient difference calculated by the Zernike moments operator. By adjusting the assembly position of the objective lens, the imaging screen and the reticle will be simultaneously in the state of maximum definition, so the parallax can be eliminated. The experimental results show that the definition evaluation function proposed in this paper has the advantages of good focusing performance, strong anti-interference ability compared with the other commonly used definition evaluation functions.

A high resolution EELS study of free-carrier variations in H2+/H+ bombarded (100)GaAs

International Nuclear Information System (INIS)

Dubois, L.H.; Schwartz, G.P.

1984-01-01

High resolution electron energy loss spectroscopy (EELS) has been used to examine whether thermal recovery of the near-surface free-carrier concentration in Te-doped (100) GaAs is accomplished following low energy (250--1500 eV) hydrogen ion bombardment. For hydrogen ion impact energies below 500 eV, the nominal bulk free-carrier density is recovered by annealing at 725 K for 2 h. For comparable ion doses, the net free-carrier concentration decreases monotonically at higher impact energies under similar annealing conditions. The threshold for damage retention occurs close to the value of transmitted energy which is necessary to create either a Ga or an As interstitial point defect

Parallaxes and Proper Motions From the MCCormick Observatory: List 47

Science.gov (United States)

Ianna, Philip A.; Patterson, Richard J.; Swain, Melanie A.

1996-01-01

Trigonometric parallaxes and proper motions are presented for 32 late-type stars observed photographically with the Leander McCormick 67 cm refractor. Eighteen of the stars have no previously published parallaxes. Twenty one of the stars are K and M dwarfs identified by Vyssotsky and his collaborators. The list includes several x-ray luminous M dwarfs, a rapidly rotating spotted flare star, and two astrometric binaries.

New Parallaxes and a Convergence Analysis for the TW Hya Association

Science.gov (United States)

Donaldson, J. K.; Weinberger, A. J.; Gagné, J.; Faherty, J. K.; Boss, A. P.; Keiser, S. A.

2016-12-01

The TW Hya Association (TWA) is a nearby stellar association with an age of ˜5-10 Myr. This is an important age for studying the late stages of star and planet formation. We measure the parallaxes of 14 candidate members of TWA. That brings to 38 the total number of individual stars with fully measured kinematics, I.e., proper motion, radial velocity, and parallax, to describe their motions through the Galaxy. We analyze these kinematics to search for convergence to a smaller volume in the past, but we find that the association is never much more compact than it is at present. We show that it is difficult to measure traceback ages for associations such as TWA that have expected velocity dispersions of 1-2 km s-1 with typical measurement uncertainties. We also use our stellar distances and pre-main-sequence evolutionary tracks to find the average age of the association of 7.9 ± 1.0 Myr. Additionally, our parallax measurement of TWA 32 indicates that it should be considered a bona fide member of TWA. Two new candidate members have high membership probabilities, and we assign them TWA numbers: TWA 45 for 2MASS J11592786-4510192 and TWA 46 for 2MASS J12354615-4115531.

Whole-organ atlas imaged by label-free high-resolution photoacoustic microscopy assisted by a microtome

Science.gov (United States)

Wong, Terence T. W.; Zhang, Ruiying; Hsu, Hsun-Chia; Maslov, Konstantin I.; Shi, Junhui; Chen, Ruimin; Shung, K. Kirk; Zhou, Qifa; Wang, Lihong V.

2018-02-01

In biomedical imaging, all optical techniques face a fundamental trade-off between spatial resolution and tissue penetration. Therefore, obtaining an organelle-level resolution image of a whole organ has remained a challenging and yet appealing scientific pursuit. Over the past decade, optical microscopy assisted by mechanical sectioning or chemical clearing of tissue has been demonstrated as a powerful technique to overcome this dilemma, one of particular use in imaging the neural network. However, this type of techniques needs lengthy special preparation of the tissue specimen, which hinders broad application in life sciences. Here, we propose a new label-free three-dimensional imaging technique, named microtomy-assisted photoacoustic microscopy (mPAM), for potentially imaging all biomolecules with 100% endogenous natural staining in whole organs with high fidelity. We demonstrate the first label-free mPAM, using UV light for label-free histology-like imaging, in whole organs (e.g., mouse brains), most of them formalin-fixed and paraffin- or agarose-embedded for minimal morphological deformation. Furthermore, mPAM with dual wavelength illuminations is also employed to image a mouse brain slice, demonstrating the potential for imaging of multiple biomolecules without staining. With visible light illumination, mPAM also shows its deep tissue imaging capability, which enables less slicing and hence reduces sectioning artifacts. mPAM could potentially provide a new insight for understanding complex biological organs.

Planning for shallow high resolution seismic surveys

CSIR Research Space (South Africa)

Fourie, CJS

2008-11-01

Full Text Available of the input wave. This information can be used in conjunction with this spreadsheet to aid the geophysicist in designing shallow high resolution seismic surveys to achieve maximum resolution and penetration. This Excel spreadsheet is available free from...

New Parallaxes for the Upper Scorpius OB Association

Science.gov (United States)

Donaldson, J. K.; Weinberger, A. J.; Gagné, J.; Boss, A. P.; Keiser, S. A.

2017-11-01

Upper Scorpius is a subgroup of the nearest OB association, Scorpius-Centaurus. Its young age makes it an important association to study star and planet formation. We present parallaxes to 52 low-mass stars in Upper Scorpius, 28 of which have full kinematics. We measure ages of the individual stars by combining our measured parallaxes with pre-main-sequence evolutionary tracks. We find a significant difference in the ages of stars with and without circumstellar disks. The stars without disks have a mean age of 4.9 ± 0.8 Myr and those with disks have an older mean age of 8.2 ± 0.9 Myr. This somewhat counterintuitive result suggests that evolutionary effects in young stars can dominate their apparent ages. We also attempt to use the 28 stars with full kinematics (I.e., proper motion, radial velocity (RV), and parallax) to trace the stars back in time to their original birthplace to obtain a trackback age. As expected, given the large measurement uncertainties on available RV measurements, we find that measurement uncertainties alone cause the group to diverge after a few Myr.

Mixel camera--a new push-broom camera concept for high spatial resolution keystone-free hyperspectral imaging.

Science.gov (United States)

Høye, Gudrun; Fridman, Andrei

2013-05-06

Current high-resolution push-broom hyperspectral cameras introduce keystone errors to the captured data. Efforts to correct these errors in hardware severely limit the optical design, in particular with respect to light throughput and spatial resolution, while at the same time the residual keystone often remains large. The mixel camera solves this problem by combining a hardware component--an array of light mixing chambers--with a mathematical method that restores the hyperspectral data to its keystone-free form, based on the data that was recorded onto the sensor with large keystone. A Virtual Camera software, that was developed specifically for this purpose, was used to compare the performance of the mixel camera to traditional cameras that correct keystone in hardware. The mixel camera can collect at least four times more light than most current high-resolution hyperspectral cameras, and simulations have shown that the mixel camera will be photon-noise limited--even in bright light--with a significantly improved signal-to-noise ratio compared to traditional cameras. A prototype has been built and is being tested.

Fall speed measurement and high-resolution multi-angle photography of hydrometeors in free fall

Directory of Open Access Journals (Sweden)

T. J. Garrett

2012-11-01

Full Text Available We describe here a new instrument for imaging hydrometeors in free fall. The Multi-Angle Snowflake Camera (MASC captures high-resolution photographs of hydrometeors from three angles while simultaneously measuring their fall speed. Based on the stereoscopic photographs captured over the two months of continuous measurements obtained at a high altitude location within the Wasatch Front in Utah, we derive statistics for fall speed, hydrometeor size, shape, orientation and aspect ratio. From a selection of the photographed hydrometeors, an illustration is provided for how the instrument might be used for making improved microwave scattering calculations. Complex, aggregated snowflake shapes appear to be more strongly forward scattering, at the expense of reduced back-scatter, than heavily rimed graupel particles of similar size.

A cloud mask methodology for high resolution remote sensing data combining information from high and medium resolution optical sensors

Science.gov (United States)

Sedano, Fernando; Kempeneers, Pieter; Strobl, Peter; Kucera, Jan; Vogt, Peter; Seebach, Lucia; San-Miguel-Ayanz, Jesús

2011-09-01

This study presents a novel cloud masking approach for high resolution remote sensing images in the context of land cover mapping. As an advantage to traditional methods, the approach does not rely on thermal bands and it is applicable to images from most high resolution earth observation remote sensing sensors. The methodology couples pixel-based seed identification and object-based region growing. The seed identification stage relies on pixel value comparison between high resolution images and cloud free composites at lower spatial resolution from almost simultaneously acquired dates. The methodology was tested taking SPOT4-HRVIR, SPOT5-HRG and IRS-LISS III as high resolution images and cloud free MODIS composites as reference images. The selected scenes included a wide range of cloud types and surface features. The resulting cloud masks were evaluated through visual comparison. They were also compared with ad-hoc independently generated cloud masks and with the automatic cloud cover assessment algorithm (ACCA). In general the results showed an agreement in detected clouds higher than 95% for clouds larger than 50 ha. The approach produced consistent results identifying and mapping clouds of different type and size over various land surfaces including natural vegetation, agriculture land, built-up areas, water bodies and snow.

Ages of Globular Clusters from HIPPARCOS Parallaxes of Local Subdwarfs

Science.gov (United States)

Gratton, Raffaele G.; Fusi Pecci, Flavio; Carretta, Eugenio; Clementini, Gisella; Corsi, Carlo E.; Lattanzi, Mario

1997-12-01

We report here initial but strongly conclusive results for absolute ages of Galactic globular clusters (GGCs). This study is based on high-precision trigonometric parallaxes from the HIPPARCOS satellite coupled with accurate metal abundances ([Fe/H], [O/Fe], and [α/Fe]) from high-resolution spectroscopy for a sample of about thirty subdwarfs. Systematic effects due to star selection (Lutz-Kelker corrections to parallaxes) and the possible presence of undetected binaries in the sample of bona fide single stars are examined, and appropriate corrections are estimated. They are found to be small for our sample. The new data allow us to reliably define the absolute location of the main sequence (MS) as a function of metallicity. These results are then used to derive distances and ages for a carefully selected sample of nine globular clusters having metallicities determined from high-dispersion spectra of individual giants according to a procedure totally consistent with that used for the field subdwarfs. Very precise and homogeneous reddening values have also been independently determined for these clusters. Random errors for our distance moduli are +/-0.08 mag, and systematic errors are likely of the same order of magnitude. These very accurate distances allow us to derive ages with internal errors of ~12% (+/-1.5 Gyr). The main results are: 1. HIPPARCOS parallaxes are smaller than corresponding ground-based measurements, leading, in turn, to longer distance moduli (~0.2 mag) and younger ages (~2.8 Gyr). 2. The distance to NGC 6752 derived from our MS fitting is consistent with that determined using the white dwarf cooling sequence. 3. The relation between the zero-age HB (ZAHB) absolute magnitude and metallicity for the nine program clusters is MV(ZAHB)=(0.22+/-0.09)([Fe/H]+1.5)+(0.49+/-0.04) . This relation is fairly consistent with some of the most recent theoretical models. Within quoted errors, the slope is in agreement with that given by the Baade-Wesselink (BW

THE INFLUENCE OF SPATIAL RESOLUTION ON NONLINEAR FORCE-FREE MODELING

Energy Technology Data Exchange (ETDEWEB)

DeRosa, M. L.; Schrijver, C. J. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover St. B/252, Palo Alto, CA 94304 (United States); Wheatland, M. S.; Gilchrist, S. A. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia); Leka, K. D.; Barnes, G. [NorthWest Research Associates, 3380 Mitchell Ln., Boulder, CO 80301 (United States); Amari, T.; Canou, A. [CNRS, Centre de Physique Théorique de l’École Polytechnique, F-91128, Palaiseau Cedex (France); Thalmann, J. K. [Institute of Physics/IGAM, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Valori, G. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Wiegelmann, T. [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077, Göttingen (Germany); Malanushenko, A. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Sun, X. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Régnier, S. [Department of Mathematics and Information Sciences, Faculty of Engineering and Environment, Northumbria University, Newcastle-Upon-Tyne, NE1 8ST (United Kingdom)

2015-10-01

The nonlinear force-free field (NLFFF) model is often used to describe the solar coronal magnetic field, however a series of earlier studies revealed difficulties in the numerical solution of the model in application to photospheric boundary data. We investigate the sensitivity of the modeling to the spatial resolution of the boundary data, by applying multiple codes that numerically solve the NLFFF model to a sequence of vector magnetogram data at different resolutions, prepared from a single Hinode/Solar Optical Telescope Spectro-Polarimeter scan of NOAA Active Region 10978 on 2007 December 13. We analyze the resulting energies and relative magnetic helicities, employ a Helmholtz decomposition to characterize divergence errors, and quantify changes made by the codes to the vector magnetogram boundary data in order to be compatible with the force-free model. This study shows that NLFFF modeling results depend quantitatively on the spatial resolution of the input boundary data, and that using more highly resolved boundary data yields more self-consistent results. The free energies of the resulting solutions generally trend higher with increasing resolution, while relative magnetic helicity values vary significantly between resolutions for all methods. All methods require changing the horizontal components, and for some methods also the vertical components, of the vector magnetogram boundary field in excess of nominal uncertainties in the data. The solutions produced by the various methods are significantly different at each resolution level. We continue to recommend verifying agreement between the modeled field lines and corresponding coronal loop images before any NLFFF model is used in a scientific setting.

Refinement procedure for the image alignment in high-resolution electron tomography

International Nuclear Information System (INIS)

Houben, L.; Bar Sadan, M.

2011-01-01

High-resolution electron tomography from a tilt series of transmission electron microscopy images requires an accurate image alignment procedure in order to maximise the resolution of the tomogram. This is the case in particular for ultra-high resolution where even very small misalignments between individual images can dramatically reduce the fidelity of the resultant reconstruction. A tomographic-reconstruction based and marker-free method is proposed, which uses an iterative optimisation of the tomogram resolution. The method utilises a search algorithm that maximises the contrast in tomogram sub-volumes. Unlike conventional cross-correlation analysis it provides the required correlation over a large tilt angle separation and guarantees a consistent alignment of images for the full range of object tilt angles. An assessment based on experimental reconstructions shows that the marker-free procedure is competitive to the reference of marker-based procedures at lower resolution and yields sub-pixel accuracy even for simulated high-resolution data. -- Highlights: → Alignment procedure for electron tomography based on iterative tomogram contrast optimisation. → Marker-free, independent of object, little user interaction. → Accuracy competitive with fiducial marker methods and suited for high-resolution tomography.

View synthesis using parallax invariance

Science.gov (United States)

Dornaika, Fadi

2001-06-01

View synthesis becomes a focus of attention of both the computer vision and computer graphics communities. It consists of creating novel images of a scene as it would appear from novel viewpoints. View synthesis can be used in a wide variety of applications such as video compression, graphics generation, virtual reality and entertainment. This paper addresses the following problem. Given a dense disparity map between two reference images, we would like to synthesize a novel view of the same scene associated with a novel viewpoint. Most of the existing work is relying on building a set of 3D meshes which are then projected onto the new image (the rendering process is performed using texture mapping). The advantages of our view synthesis approach are as follows. First, the novel view is specified by a rotation and a translation which are the most natural way to express the virtual location of the camera. Second, the approach is able to synthesize highly realistic images whose viewing position is significantly far away from the reference viewpoints. Third, the approach is able to handle the visibility problem during the synthesis process. Our developed framework has two main steps. The first step (analysis step) consists of computing the homography at infinity, the epipoles, and thus the parallax field associated with the reference images. The second step (synthesis step) consists of warping the reference image into a new one, which is based on the invariance of the computed parallax field. The analysis step is working directly on the reference views, and only need to be performed once. Examples of synthesizing novel views using either feature correspondences or dense disparity map have demonstrated the feasibility of the proposed approach.

DISTANCE SCALE ZERO POINTS FROM GALACTIC RR LYRAE STAR PARALLAXES

Energy Technology Data Exchange (ETDEWEB)

Benedict, G. Fritz; McArthur, Barbara E.; Barnes, Thomas G. [McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Feast, Michael W. [Centre for Astrophysics, Cosmology and Gravitation, Astronomy Department, University of Cape Town, Rondebosch 7701 (South Africa); Harrison, Thomas E. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Bean, Jacob L.; Kolenberg, Katrien [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Menzies, John W.; Laney, C. D. [South African Astronomical Observatory, Observatory 7935 (South Africa); Chaboyer, Brian [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Fossati, Luca [Department of Physics and Astronomy, Open University, Milton Keynes MK7 6AA (United Kingdom); Nesvacil, Nicole [Institute of Astronomy, University of Vienna, A-1180 Vienna (Austria); Smith, Horace A. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Kochukhov, Oleg [Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Nelan, Edmund P.; Taylor, Denise [STScI, Baltimore, MD 21218 (United States); Shulyak, D. V. [Institute of Astrophysics, Georg-August-University, Friedrich-Hund-Platz 1, D-37077 Goettingen (Germany); Freedman, Wendy L. [The Observatories, Carnegie Institution of Washington, Pasadena, CA 91101 (United States)

2011-12-15

We present new absolute trigonometric parallaxes and proper motions for seven Population II variable stars-five RR Lyr variables: RZ Cep, XZ Cyg, SU Dra, RR Lyr, and UV Oct; and two type 2 Cepheids: VY Pyx and {kappa} Pav. We obtained these results with astrometric data from Fine Guidance Sensors, white-light interferometers on Hubble Space Telescope. We find absolute parallaxes in milliseconds of arc: RZ Cep, 2.12 {+-} 0.16 mas; XZ Cyg, 1.67 {+-} 0.17 mas; SU Dra, 1.42 {+-} 0.16 mas; RR Lyr, 3.77 {+-} 0.13 mas; UV Oct, 1.71 {+-} 0.10 mas; VY Pyx, 6.44 {+-} 0.23 mas; and {kappa} Pav, 5.57 {+-} 0.28 mas; an average {sigma}{sub {pi}}/{pi} = 5.4%. With these parallaxes, we compute absolute magnitudes in V and K bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias. Using these RR Lyrae variable star absolute magnitudes, we then derive zero points for M{sub V} -[Fe/H] and M{sub K} -[Fe/H]-log P relations. The technique of reduced parallaxes corroborates these results. We employ our new results to determine distances and ages of several Galactic globular clusters and the distance of the Large Magellanic Cloud. The latter is close to that previously derived from Classical Cepheids uncorrected for any metallicity effect, indicating that any such effect is small. We also discuss the somewhat puzzling results obtained for our two type 2 Cepheids.

CCD Parallaxes for 309 Late-type Dwarfs and Subdwarfs

Energy Technology Data Exchange (ETDEWEB)

Dahn, Conard C.; Harris, Hugh C.; Subasavage, John P.; Ables, Harold D.; Guetter, Harry H.; Harris, Fred H.; Luginbuhl, Christian B.; Monet, Alice B.; Monet, David G.; Munn, Jeffrey A.; Pier, Jeffrey R.; Stone, Ronald C.; Vrba, Frederick J.; Walker, Richard L.; Tilleman, Trudy M. [US Naval Observatory, Flagstaff Station, 10391 W. Naval Observatory Road, Flagstaff, AZ 86005-8521 (United States); Canzian, Blaise J. [L-3 Communications/Brashear, 615 Epsilon Drive, Pittsburgh, PA 15238-2807 (United States); Henden, Arne H. [AAVSO, Cambridge, MA 02138 (United States); Leggett, S. K. [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, HI 96720 (United States); Levine, Stephen E., E-mail: jsubasavage@nofs.navy.mil [Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001-4499 (United States)

2017-10-01

New, updated, and/or revised CCD parallaxes determined with the Strand Astrometric Reflector at the Naval Observatory Flagstaff Station are presented. Included are results for 309 late-type dwarf and subdwarf stars observed over the 30+ years that the program operated. For 124 of the stars, parallax determinations from other investigators have already appeared in the literature and we compare the different results. Also included here are new or updated VI photometry on the Johnson–Kron-Cousins system for all but a few of the faintest targets. Together with 2MASS JHK{sub s} near-infrared photometry, a sample of absolute magnitude versus color and color versus color diagrams are constructed. Because large proper motion was a prime criterion for targeting the stars, the majority turn out to be either M-type subdwarfs or late M-type dwarfs. The sample also includes 50 dwarf or subdwarf L-type stars, and four T dwarfs. Possible halo subdwarfs are identified in the sample based on tangential velocity, subluminosity, and spectral type. Residuals from the solutions for parallax and proper motion for several stars show evidence of astrometric perturbations.

Fabrication of perforated isoporous membranes via a transfer-free strategy: enabling high-resolution separation of cells.

Science.gov (United States)

Ou, Yang; Lv, Chang-Jiang; Yu, Wei; Mao, Zheng-Wei; Wan, Ling-Shu; Xu, Zhi-Kang

2014-12-24

Thin perforated membranes with ordered pores are ideal barriers for high-resolution and high-efficiency selective transport and separation of biological species. However, for self-assembled thin membranes with a thickness less than several micrometers, an additional step of transferring the membranes onto porous supports is generally required. In this article, we present a facile transfer-free strategy for fabrication of robust perforated composite membranes via the breath figure process, and for the first time, demonstrate the application of the membranes in high-resolution cell separation of yeasts and lactobacilli without external pressure, achieving almost 100% rejection of yeasts and more than 70% recovery of lactobacilli with excellent viability. The avoidance of the transfer step simplifies the fabrication procedure of composite membranes and greatly improves the membrane homogeneity. Moreover, the introduction of an elastic triblock copolymer increases the interfacial strength between the membrane and the support, and allows the preservation of composite membranes in a dry state. Such perforated ordered membranes can also be applied in other size-based separation systems, enabling new opportunities in bioseparation and biosensors.

Probing interferometric parallax with interplanetary spacecraft

Science.gov (United States)

Rodeghiero, G.; Gini, F.; Marchili, N.; Jain, P.; Ralston, J. P.; Dallacasa, D.; Naletto, G.; Possenti, A.; Barbieri, C.; Franceschini, A.; Zampieri, L.

2017-07-01

We describe an experimental scenario for testing a novel method to measure distance and proper motion of astronomical sources. The method is based on multi-epoch observations of amplitude or intensity correlations between separate receiving systems. This technique is called Interferometric Parallax, and efficiently exploits phase information that has traditionally been overlooked. The test case we discuss combines amplitude correlations of signals from deep space interplanetary spacecraft with those from distant galactic and extragalactic radio sources with the goal of estimating the interplanetary spacecraft distance. Interferometric parallax relies on the detection of wavefront curvature effects in signals collected by pairs of separate receiving systems. The method shows promising potentialities over current techniques when the target is unresolved from the background reference sources. Developments in this field might lead to the construction of an independent, geometrical cosmic distance ladder using a dedicated project and future generation instruments. We present a conceptual overview supported by numerical estimates of its performances applied to a spacecraft orbiting the Solar System. Simulations support the feasibility of measurements with a simple and time-saving observational scheme using current facilities.

Psychophysical evidence for auditory motion parallax.

Science.gov (United States)

Genzel, Daria; Schutte, Michael; Brimijoin, W Owen; MacNeilage, Paul R; Wiegrebe, Lutz

2018-04-17

Distance is important: From an ecological perspective, knowledge about the distance to either prey or predator is vital. However, the distance of an unknown sound source is particularly difficult to assess, especially in anechoic environments. In vision, changes in perspective resulting from observer motion produce a reliable, consistent, and unambiguous impression of depth known as motion parallax. Here we demonstrate with formal psychophysics that humans can exploit auditory motion parallax, i.e., the change in the dynamic binaural cues elicited by self-motion, to assess the relative depths of two sound sources. Our data show that sensitivity to relative depth is best when subjects move actively; performance deteriorates when subjects are moved by a motion platform or when the sound sources themselves move. This is true even though the dynamic binaural cues elicited by these three types of motion are identical. Our data demonstrate a perceptual strategy to segregate intermittent sound sources in depth and highlight the tight interaction between self-motion and binaural processing that allows assessment of the spatial layout of complex acoustic scenes.

High resolution beam profiling of X-ray free electron laser radiation by polymer imprint development.

Science.gov (United States)

Rösner, Benedikt; Döring, Florian; Ribič, Primož R; Gauthier, David; Principi, Emiliano; Masciovecchio, Claudio; Zangrando, Marco; Vila-Comamala, Joan; De Ninno, Giovanni; David, Christian

2017-11-27

High resolution metrology of beam profiles is presently a major challenge at X-ray free electron lasers. We demonstrate a characterization method based on beam imprints in poly (methyl methacrylate). By immersing the imprints formed at 47.8 eV into organic solvents, the regions exposed to the beam are removed similar to resist development in grayscale lithography. This allows for extending the sensitivity of the method by more than an order of magnitude compared to the established analysis of imprints created solely by ablation. Applying the Beer-Lambert law for absorption, the intensity distribution in a micron-sized focus can be reconstructed from one single shot with a high dynamic range, exceeding 10 3 . The procedure described here allows for beam characterization at free electron lasers revealing even faint beam tails, which are not accessible when using ablation imprint methods. We demonstrate the greatly extended dynamic range on developed imprints taken in focus of conventional Fresnel zone plates and spiral zone plates producing beams with a topological charge.

Gaia Data Release 1. Testing parallaxes with local Cepheids and RR Lyrae stars

NARCIS (Netherlands)

Gaia Collaboration, [Unknown; Clementini, G.; Eyer, L.; Ripepi, V.; Marconi, M.; Muraveva, T.; Garofalo, A.; Sarro, L. M.; Palmer, M.; Luri, X.; Molinaro, R.; Rimoldini, L.; Szabados, L.; Musella, I.; Anderson, R. I.; Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A.; Vallenari, A.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; van Leeuwen, F.; Walton, N. A.; Aerts, C.; Arenou, F.; Cropper, M.; Drimmel, R.; Høg, E.; Katz, D.; Lattanzi, M. G.; O'Mullane, W.; Grebel, E. K.; Holland, A. D.; Huc, C.; Passot, X.; Perryman, M.; Bramante, L.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Hernández, J.; Jean-Antoine-Piccolo, A.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Ordóñez-Blanco, D.; Panuzzo, P.; Portell, J.; Richards, P. J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Torra, J.; Els, S. G.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Lock, T.; Mercier, E.; Altmann, M.; Andrae, R.; Astraatmadja, T. L.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Busso, G.; Carry, B.; Cellino, A.; Cowell, S.; Creevey, O.; Cuypers, J.; Davidson, M.; De Ridder, J.; de Torres, A.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Frémat, Y.; García-Torres, M.; Gosset, E.; Halbwachs, J.-L.; Hambly, N. C.; Harrison, D. L.; Hauser, M.; Hestroffer, D.; Hodgkin, S. T.; Huckle, H. E.; Hutton, A.; Jasniewicz, G.; Jordan, S.; Kontizas, M.; Korn, A. J.; Lanzafame, A. C.; Manteiga, M.; Moitinho, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J.-M.; Recio-Blanco, A.; Robin, A. C.; Siopis, C.; Smith, M.; Smith, K. W.; Sozzetti, A.; Thuillot, W.; van Reeven, W.; Viala, Y.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aguado, J. J.; Allan, P. M.; Allasia, W.; Altavilla, G.; Álvarez, M. A.; Alves, J.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Antón, S.; Arcay, B.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Barache, C.; Barata, C.; Barbier, A.; Barblan, F.; Barrado y Navascués, D.; Barros, M.; Barstow, M. A.; Becciani, U.; Bellazzini, M.; Bello García, A.; Belokurov, V.; Bendjoya, P.; Berihuete, A.; Bianchi, L.; Bienaymé, O.; Billebaud, F.; Blagorodnova, N.; Blanco-Cuaresma, S.; Boch, T.; Bombrun, A.; Borrachero, R.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Breddels, M. A.; Brouillet, N.; Brüsemeister, T.; Bucciarelli, B.; Burgess, P.; Burgon, R.; Burlacu, A.; Busonero, D.; Buzzi, R.; Caffau, E.; Cambras, J.; Campbell, H.; Cancelliere, R.; Cantat-Gaudin, T.; Carlucci, T.; Carrasco, J. M.; Castellani, M.; Charlot, P.; Charnas, J.; Chiavassa, A.; Clotet, M.; Cocozza, G.; Collins, R. S.; Costigan, G.; Crifo, F.; Cross, N. J. G.; Crosta, M.; Crowley, C.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; De Cat, P.; de Felice, F.; de Laverny, P.; De Luise, F.; De March, R.; de Souza, R.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Distefano, E.; Dolding, C.; Dos Anjos, S.; Drazinos, P.; Durán, J.; Dzigan, Y.; Edvardsson, B.; Enke, H.; Evans, N. W.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernández-Hernández, J.; Fernique, P.; Fienga, A.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fouesneau, M.; Fraile, E.; Fraser, M.; Fuchs, J.; Gai, M.; Galleti, S.; Galluccio, L.; Garabato, D.; García-Sedano, F.; Garralda, N.; Gavras, P.; Gerssen, J.; Geyer, R.; Gilmore, G.; Girona, S.; Giuffrida, G.; Gomes, M.; González-Marcos, A.; González-Núñez, J.; González-Vidal, J. J.; Granvik, M.; Guerrier, A.; Guillout, P.; Guiraud, J.; Gúrpide, A.; Gutiérrez-Sánchez, R.; Guy, L. P.; Haigron, R.; Hatzidimitriou, D.; Haywood, M.; Heiter, U.; Helmi, A.; Hobbs, D.; Hofmann, W.; Holl, B.; Holland, G.; Hunt, J. A. S.; Hypki, A.; Icardi, V.; Irwin, M.; Jevardat de Fombelle, G.; Jofré, P.; Jonker, P. G.; Jorissen, A.; Julbe, F.; Karampelas, A.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Koubsky, P.; Krone-Martins, A.; Kudryashova, M.; Bachchan, R. K.; Lacoste-Seris, F.; Lanza, A. F.; Lavigne, J.-B.; Le Poncin-Lafitte, C.; Lebreton, Y.; Lebzelter, T.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lemaitre, V.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; Löffler, W.; López, M.; Lorenz, D.; MacDonald, I.; Magalhães Fernandes, T.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marinoni, S.; Marrese, P. M.; Marschalkó, G.; Marshall, D. J.; Martín-Fleitas, J. M.; Martino, M.; Mary, N.; Matijevič, G.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Miranda, B. M. H.; Molina, D.; Molinaro, M.; Molnár, L.; Moniez, M.; Montegriffo, P.; Mor, R.; Mora, A.; Morbidelli, R.; Morel, T.; Morgenthaler, S.; Morris, D.; Mulone, A. F.; Narbonne, J.; Nelemans, G.; Nicastro, L.; Noval, L.; Ordénovic, C.; Ordieres-Meré, J.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Parsons, P.; Pecoraro, M.; Pedrosa, R.; Pentikäinen, H.; Pichon, B.; Piersimoni, A. M.; Pineau, F.-X.; Plachy, E.; Plum, G.; Poujoulet, E.; Prša, A.; Pulone, L.; Ragaini, S.; Rago, S.; Rambaux, N.; Ramos-Lerate, M.; Ranalli, P.; Rauw, G.; Read, A.; Regibo, S.; Reylé, C.; Ribeiro, R. A.; Riva, A.; Rixon, G.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Segransan, D.; Shih, I.-C.; Smareglia, R.; Smart, R. L.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Süveges, M.; Surdej, J.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Tingley, B.; Trager, S. C.; Turon, C.; Ulla, A.; Utrilla, E.; Valentini, G.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Varadi, M.; Vecchiato, A.; Veljanoski, J.; Via, T.; Vicente, D.; Vogt, S.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Weingrill, K.; Wevers, T.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Zucker, S.; Zurbach, C.; Zwitter, T.; Alecu, A.; Allen, M.; Allende Prieto, C.; Amorim, A.; Anglada-Escudé, G.; Arsenijevic, V.; Azaz, S.; Balm, P.; Beck, M.; Bernstein, H.-H.; Bigot, L.; Bijaoui, A.; Blasco, C.; Bonfigli, M.; Bono, G.; Boudreault, S.; Bressan, A.; Brown, S.; Brunet, P.-M.; Bunclark†, P.; Buonanno, R.; Butkevich, A. G.; Carret, C.; Carrion, C.; Chemin, L.; Chéreau, F.; Corcione, L.; Darmigny, E.; de Boer, K. S.; de Teodoro, P.; de Zeeuw, P. T.; Delle Luche, C.; Domingues, C. D.; Dubath, P.; Fodor, F.; Frézouls, B.; Fries, A.; Fustes, D.; Fyfe, D.; Gallardo, E.; Gallegos, J.; Gardiol, D.; Gebran, M.; Gomboc, A.; Gómez, A.; Grux, E.; Gueguen, A.; Heyrovsky, A.; Hoar, J.; Iannicola, G.; Isasi Parache, Y.; Janotto, A.-M.; Joliet, E.; Jonckheere, A.; Keil, R.; Kim, D.-W.; Klagyivik, P.; Klar, J.; Knude, J.; Kochukhov, O.; Kolka, I.; Kos, J.; Kutka, A.; Lainey, V.; LeBouquin, D.; Liu, C.; Loreggia, D.; Makarov, V. V.; Marseille, M. G.; Martayan, C.; Martinez-Rubi, O.; Massart, B.; Meynadier, F.; Mignot, S.; Munari, U.; Nguyen, A.-T.; Nordlander, T.; O'Flaherty, K. S.; Ocvirk, P.; Olias Sanz, A.; Ortiz, P.; Osorio, J.; Oszkiewicz, D.; Ouzounis, A.; Park, P.; Pasquato, E.; Peltzer, C.; Peralta, J.; Péturaud, F.; Pieniluoma, T.; Pigozzi, E.; Poels†, J.; Prat, G.; Prod'homme, T.; Raison, F.; Rebordao, J. M.; Risquez, D.; Rocca-Volmerange, B.; Rosen, S.; Ruiz-Fuertes, M. I.; Russo, F.; Serraller Vizcaino, I.; Short, A.; Siebert, A.; Silva, H.; Sinachopoulos, D.; Slezak, E.; Soffel, M.; Sosnowska, D.; Straižys, V.; ter Linden, M.; Terrell, D.; Theil, S.; Tiede, C.; Troisi, L.; Tsalmantza, P.; Tur, D.; Vaccari, M.; Vachier, F.; Valles, P.; Van Hamme, W.; Veltz, L.; Virtanen, J.; Wallut, J.-M.; Wichmann, R.; Wilkinson, M. I.; Ziaeepour, H.; Zschocke, S.

2017-01-01

Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims: In order to test these first parallax

METHODS OF STEREO PAIR IMAGES FORMATION WITH A GIVEN PARALLAX VALUE

Directory of Open Access Journals (Sweden)

Viktoriya G. Chafonova

2014-11-01

Full Text Available Two new complementary methods of stereo pair images formation are proposed. The first method is based on finding the maximum correlation between the gradient images of the left and right frames. The second one implies the finding of the shift between two corresponding key points of images for a stereo pair found by a detector of point features. These methods give the possibility to set desired values of vertical and horizontal parallaxes for the selected object in the image. Application of these methods makes it possible to measure the parallax values for the objects on the final stereo pair in pixels and / or the percentage of the total image size. It gives the possibility to predict the possible excesses in parallax values while stereo pair printing or projection. The proposed methods are easily automated after object selection, for which a predetermined value of the horizontal parallax will be exposed. Stereo pair images superposition using the key points takes less than one second. The method with correlation application requires a little bit more computing time, but makes it possible to control and superpose undivided anaglyph image. The proposed methods of stereo pair formation can find their application in programs for editing and processing images of a stereo pair, in the monitoring devices for shooting cameras and in the devices for video sequence quality assessment

Trigonometric parallaxes of star forming regions in the Scutum spiral arm

International Nuclear Information System (INIS)

Sato, M.; Wu, Y. W.; Immer, K.; Zhang, B.; Sanna, A.; Brunthaler, A.; Menten, K. M.; Reid, M. J.; Dame, T. M.

2014-01-01

We report measurements of trigonometric parallaxes for six high-mass star-forming regions in the Scutum spiral arm of the Milky Way as part of the BeSSeL Survey. Combining our measurements with 10 previous measurements from the BeSSeL Survey yields a total sample of 16 sources in the Scutum arm with trigonometric parallaxes in the Galactic longitude range from 5° to 32°. Assuming a logarithmic spiral model, we estimate a pitch angle of 19.°8 ± 3.°1 for the Scutum arm, which is larger than pitch angles reported for other spiral arms. The high pitch angle of the arm may be due to the arm's proximity to the Galactic bar. The Scutum arm sources show an average peculiar motion of 4 km s –1 slower than the Galactic rotation and 8 km s –1 toward the Galactic center. While the direction of this non-circular motion has the same sign as determined for sources in other spiral arms, the motion toward the Galactic center is greater for the Scutum arm sources.

European training network on full-parallax imaging (Conference Presentation)

Science.gov (United States)

Martínez-Corral, Manuel; Saavedra, Genaro

2017-05-01

Current displays are far from truly recreating visual reality. This requires a full-parallax display that can reproduce radiance field emanated from the real scenes. The develop-ment of such technology will require a new generation of researchers trained both in the physics, and in the biology of human vision. The European Training Network on Full-Parallax Imaging (ETN-FPI) aims at developing this new generation. Under H2020 funding ETN-FPI brings together 8 beneficiaries and 8 partner organizations from five EU countries with the aim of training 15 talented pre-doctoral students to become future research leaders in this area. In this contribution we will explain the main objectives of the network, and specifically the advances obtained at the University of Valencia.

High spatial and temporal resolution retrospective cine cardiovascular magnetic resonance from shortened free breathing real-time acquisitions.

Science.gov (United States)

Xue, Hui; Kellman, Peter; Larocca, Gina; Arai, Andrew E; Hansen, Michael S

2013-11-14

Cine cardiovascular magnetic resonance (CMR) is challenging in patients who cannot perform repeated breath holds. Real-time, free-breathing acquisition is an alternative, but image quality is typically inferior. There is a clinical need for techniques that achieve similar image quality to the segmented cine using a free breathing acquisition. Previously, high quality retrospectively gated cine images have been reconstructed from real-time acquisitions using parallel imaging and motion correction. These methods had limited clinical applicability due to lengthy acquisitions and volumetric measurements obtained with such methods have not previously been evaluated systematically. This study introduces a new retrospective reconstruction scheme for real-time cine imaging which aims to shorten the required acquisition. A real-time acquisition of 16-20s per acquired slice was inputted into a retrospective cine reconstruction algorithm, which employed non-rigid registration to remove respiratory motion and SPIRiT non-linear reconstruction with temporal regularization to fill in missing data. The algorithm was used to reconstruct cine loops with high spatial (1.3-1.8 × 1.8-2.1 mm²) and temporal resolution (retrospectively gated, 30 cardiac phases, temporal resolution 34.3 ± 9.1 ms). Validation was performed in 15 healthy volunteers using two different acquisition resolutions (256 × 144/192 × 128 matrix sizes). For each subject, 9 to 12 short axis and 3 long axis slices were imaged with both segmented and real-time acquisitions. The retrospectively reconstructed real-time cine images were compared to a traditional segmented breath-held acquisition in terms of image quality scores. Image quality scoring was performed by two experts using a scale between 1 and 5 (poor to good). For every subject, LAX and three SAX slices were selected and reviewed in the random order. The reviewers were blinded to the reconstruction approach and acquisition protocols and

Artifact free T2*-weighted imaging at high spatial resolution using segmented EPI sequences

International Nuclear Information System (INIS)

Heiler, Patrick Michael; Schad, Lothar Rudi; Schmitter, Sebastian

2010-01-01

The aim of this work was the development of novel measurement techniques that acquire high resolution T2 * -weighted datasets in measurement times as short as possible without suffering from noticeable blurring and ghosting artifacts. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences. One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging. For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1.5, leading to an SNR increase by approximately √2. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting. Assuming sequence parameters as feasible for fMRI experiments, artifact free T2 * -weighted images with a matrix size of 256 x 256 leading to an in-plane resolution in the submillimeter range can be obtained in about 2 s per slice. (orig.)

VISIDEP™: visual image depth enhancement by parallax induction

Science.gov (United States)

Jones, Edwin R.; McLaurin, A. P.; Cathey, LeConte

1984-05-01

The usual descriptions of depth perception have traditionally required the simultaneous presentation of disparate views presented to separate eyes with the concomitant demand that the resulting binocular parallax be horizontally aligned. Our work suggests that the visual input information is compared in a short-term memory buffer which permits the brain to compute depth as it is normally perceived. However, the mechanism utilized is also capable of receiving and processing the stereographic information even when it is received monocularly or when identical inputs are simultaneously fed to both eyes. We have also found that the restriction to horizontally displaced images is not a necessary requirement and that improvement in image acceptability is achieved by the use of vertical parallax. Use of these ideas permit the presentation of three-dimensional scenes on flat screens in full color without the encumbrance of glasses or other viewing aids.

Refinement procedure for the image alignment in high-resolution electron tomography.

Science.gov (United States)

Houben, L; Bar Sadan, M

2011-01-01

High-resolution electron tomography from a tilt series of transmission electron microscopy images requires an accurate image alignment procedure in order to maximise the resolution of the tomogram. This is the case in particular for ultra-high resolution where even very small misalignments between individual images can dramatically reduce the fidelity of the resultant reconstruction. A tomographic-reconstruction based and marker-free method is proposed, which uses an iterative optimisation of the tomogram resolution. The method utilises a search algorithm that maximises the contrast in tomogram sub-volumes. Unlike conventional cross-correlation analysis it provides the required correlation over a large tilt angle separation and guarantees a consistent alignment of images for the full range of object tilt angles. An assessment based on experimental reconstructions shows that the marker-free procedure is competitive to the reference of marker-based procedures at lower resolution and yields sub-pixel accuracy even for simulated high-resolution data. Copyright © 2011 Elsevier B.V. All rights reserved.

A Probabilistic Approach to Fitting Period–luminosity Relations and Validating Gaia Parallaxes

Energy Technology Data Exchange (ETDEWEB)

Sesar, Branimir; Fouesneau, Morgan; Bailer-Jones, Coryn A. L.; Gould, Andy; Rix, Hans-Walter [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Price-Whelan, Adrian M., E-mail: bsesar@mpia.de [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2017-04-01

Pulsating stars, such as Cepheids, Miras, and RR Lyrae stars, are important distance indicators and calibrators of the “cosmic distance ladder,” and yet their period–luminosity–metallicity (PLZ) relations are still constrained using simple statistical methods that cannot take full advantage of available data. To enable optimal usage of data provided by the Gaia mission, we present a probabilistic approach that simultaneously constrains parameters of PLZ relations and uncertainties in Gaia parallax measurements. We demonstrate this approach by constraining PLZ relations of type ab RR Lyrae stars in near-infrared W 1 and W 2 bands, using Tycho- Gaia Astrometric Solution (TGAS) parallax measurements for a sample of ≈100 type ab RR Lyrae stars located within 2.5 kpc of the Sun. The fitted PLZ relations are consistent with previous studies, and in combination with other data, deliver distances precise to 6% (once various sources of uncertainty are taken into account). To a precision of 0.05 mas (1 σ ), we do not find a statistically significant offset in TGAS parallaxes for this sample of distant RR Lyrae stars (median parallax of 0.8 mas and distance of 1.4 kpc). With only minor modifications, our probabilistic approach can be used to constrain PLZ relations of other pulsating stars, and we intend to apply it to Cepheid and Mira stars in the near future.

Stress Free Multilayer Coating for High Resolution X-ray Mirrors

Data.gov (United States)

National Aeronautics and Space Administration — Most of X-ray optics research and development in the US is to build a high resolution, large collecting area and light-weight optic, namely an soft X-ray mirror for...

A full-parallax 3D display with restricted viewing zone tracking viewer's eye

Science.gov (United States)

Beppu, Naoto; Yendo, Tomohiro

2015-03-01

The Three-Dimensional (3D) vision became widely known as familiar imaging technique now. The 3D display has been put into practical use in various fields, such as entertainment and medical fields. Development of 3D display technology will play an important role in a wide range of fields. There are various ways to the method of displaying 3D image. There is one of the methods that showing 3D image method to use the ray reproduction and we focused on it. This method needs many viewpoint images when achieve a full-parallax because this method display different viewpoint image depending on the viewpoint. We proposed to reduce wasteful rays by limiting projector's ray emitted to around only viewer using a spinning mirror, and to increase effectiveness of display device to achieve a full-parallax 3D display. We propose a method by using a tracking viewer's eye, a high-speed projector, a rotating mirror that tracking viewer (a spinning mirror), a concave mirror array having the different vertical slope arranged circumferentially (a concave mirror array), a cylindrical mirror. About proposed method in simulation, we confirmed the scanning range and the locus of the movement in the horizontal direction of the ray. In addition, we confirmed the switching of the viewpoints and convergence performance in the vertical direction of rays. Therefore, we confirmed that it is possible to realize a full-parallax.

A High-Resolution Stopwatch for Cents

Science.gov (United States)

Gingl, Z.; Kopasz, K.

2011-01-01

A very low-cost, easy-to-make stopwatch is presented to support various experiments in mechanics. The high-resolution stopwatch is based on two photodetectors connected directly to the microphone input of a sound card. Dedicated free open-source software has been developed and made available to download. The efficiency is demonstrated by a free…

Augmented reality glass-free three-dimensional display with the stereo camera

Science.gov (United States)

Pang, Bo; Sang, Xinzhu; Chen, Duo; Xing, Shujun; Yu, Xunbo; Yan, Binbin; Wang, Kuiru; Yu, Chongxiu

2017-10-01

An improved method for Augmented Reality (AR) glass-free three-dimensional (3D) display based on stereo camera used for presenting parallax contents from different angle with lenticular lens array is proposed. Compared with the previous implementation method of AR techniques based on two-dimensional (2D) panel display with only one viewpoint, the proposed method can realize glass-free 3D display of virtual objects and real scene with 32 virtual viewpoints. Accordingly, viewers can get abundant 3D stereo information from different viewing angles based on binocular parallax. Experimental results show that this improved method based on stereo camera can realize AR glass-free 3D display, and both of virtual objects and real scene have realistic and obvious stereo performance.

Artifact free T2{sup *}-weighted imaging at high spatial resolution using segmented EPI sequences

Energy Technology Data Exchange (ETDEWEB)

Heiler, Patrick Michael; Schad, Lothar Rudi [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Schmitter, Sebastian [German Cancer Research Center, Heidelberg (Germany). Dept. of Medical Physics in Radiology

2010-07-01

The aim of this work was the development of novel measurement techniques that acquire high resolution T2{sup *}-weighted datasets in measurement times as short as possible without suffering from noticeable blurring and ghosting artifacts. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences. One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging. For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1.5, leading to an SNR increase by approximately {radical}2. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting. Assuming sequence parameters as feasible for fMRI experiments, artifact free T2{sup *}-weighted images with a matrix size of 256 x 256 leading to an in-plane resolution in the submillimeter range can be obtained in about 2 s per slice. (orig.)

Novel Geometrical Concept of a High Performance Brain PET Scanner Principle, Design and Performance Estimates

CERN Document Server

Séguinot, Jacques; Chesi, Enrico Guido; Joram, C; Mathot, S; Weilhammer, P; Chamizo-Llatas, M; Correia, J G; Ribeiro da Silva, M; Garibaldi, F; De Leo, R; Nappi, E; Corsi, F; Dragone, A; Schoenahl, F; Zaidi, H

2006-01-01

We present the principle, a possible implementation and performance estimates of a novel geometrical concept for a high resolution positron emission tomograph. The concept, which can for example be implemented in a brain PET device, promisses to lead to an essentially parallax free 3D image reconstruction with excellent spatial resolution and constrast, uniform over the complete field of view. The key components are matrices of long axially oriented scintillator crystals which are read out at both extremities by segmented Hybrid Photon Detectors. We discuss the relevant design considerations for a 3D axial PET camera module, motivate parameter and material choices, and estimate its performance in terms of spatial and energy resolution. We support these estimates by Monte Carlo simulations and in some cases by first experimental results. From the performance of a camera module, we extrapolate to the reconstruction resolution of a 3D axial PET scanner in a semi-analytical way and compare it to an existing state...

The Galactic Distribution of Planets via Spitzer Microlensing Parallax

Science.gov (United States)

Gould, Andrew; Yee, Jennifer; Carey, Sean; Shvartzvald, Yossi

2018-05-01

We will measure the Galactic distribution of planets by obtaining 'microlens parallaxes' of about 200 events, including 3 planetary events, from the comparison of microlens lightcurves observed from Spitzer and Earth, which are separated by >1.5 AU in projection. The proposed observations are part of a campaign that we have conducted with Spitzer since 2014. The planets expected to be identified in this campaign when combined with previous work will yield a first statistically significant measurement of the frequency of planets in the Galactic bulge versus the Galactic disk. As we have demonstrated in three previous programs, the difference in these lightcurves yields both the 'microlens parallax' (ratio of the lens-source relative parallax) to the Einstein radius, and the direction of lens-source relative motion. For planetary events, this measurement directly yields the mass and distance of the planet. This proposal is significantly more sensitive to planets than previous work because it takes advantage of the KMTNet observing strategy that covers >85 sq.deg t >0.4/hr cadence, 24/7 from 3 southern observatories and a alert system KMTNet is implementing for 2019. This same observing program also provides a unique probe of dark objects. It will yield an improved measurement of the isolated-brown-dwarf mass function. Thirteen percent of the observations will specifically target binaries, which will probe systems with dark components (brown dwarfs, neutron stars, black holes) that are difficult or impossible to investigate by other methods. The observations and methods from this work are a test bed for WFIRST microlensing.

New Target for an Old Method: Hubble Measures Globular Cluster Parallax

Science.gov (United States)

Hensley, Kerry

2018-05-01

Measuring precise distances to faraway objects has long been a challenge in astrophysics. Now, one of the earliest techniques used to measure the distance to astrophysical objects has been applied to a metal-poor globular cluster for the first time.A Classic TechniqueAn artists impression of the European Space Agencys Gaia spacecraft. Gaia is on track to map the positions and motions of a billion stars. [ESA]Distances to nearby stars are often measured using the parallax technique tracing the tiny apparent motion of a target star against the background of more distant stars as Earth orbits the Sun. This technique has come a long way since it was first used in the 1800s to measure the distance to stars a few tens of light-years away; with the advent of space observatories like Hipparcos and Gaia, parallax can now be used to map the positions of stars out to thousands of light-years.Precise distance measurements arent only important for setting the scale of the universe, however; they can also help us better understand stellar evolution over the course of cosmic history. Stellar evolution models are often anchored to a reference star cluster, the properties of which must be known precisely. These precise properties can be readily determined for young, nearby open clusters using parallax measurements. But stellar evolution models that anchor on themore-distant, ancient, metal-poor globular clusters have been hampered by theless-precise indirect methods used tomeasure distance to these faraway clusters until now.Top: An image of NGC 6397 overlaid with the area scanned by Hubble (dashed green) and the footprint of the camera (solid green). The blue ellipse represents the parallax motion of a star in the cluster, exaggerated by a factor of ten thousand. Bottom: An example scan from this field. [Adapted from Brown et al. 2018]New Measurement to an Old ClusterThomas Brown (Space Telescope Science Institute) and collaborators used the Hubble Space Telescope todetermine the

Study of DOI resolution and imaging resolution of a PET device

International Nuclear Information System (INIS)

Saha, Lipika; Saitoh, Kazumi; Kobayashi, Shigeharu

2004-01-01

As a recent trend of DOI measurement for the PET, a simple method of utilizing the light attenuation properties of scintillation materials has been paid attention. We have studied the DOI resolutions for less expensive materials as BGO in both the bench test and the simulation by GEANT4.0. By comparison with both the results, we have recognized the importance of removing the multiple Compton absorption events to obtain the better DOI information. The simulation results for the imaging resolution suggested that its deterioration attributes to the parallax error as well as the systematic displacement inherent in the present method of 3D-reconstruction

THE ABSOLUTE MAGNITUDE OF RRc VARIABLES FROM STATISTICAL PARALLAX

International Nuclear Information System (INIS)

Kollmeier, Juna A.; Burns, Christopher R.; Thompson, Ian B.; Preston, George W.; Crane, Jeffrey D.; Madore, Barry F.; Morrell, Nidia; Prieto, José L.; Shectman, Stephen; Simon, Joshua D.; Villanueva, Edward; Szczygieł, Dorota M.; Gould, Andrew; Sneden, Christopher; Dong, Subo

2013-01-01

We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 242 RRc variables selected from the All Sky Automated Survey for which high-quality light curves, photometry, and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey. We find that M V,RRc = 0.59 ± 0.10 at a mean metallicity of [Fe/H] = –1.59. This is to be compared with previous estimates for RRab stars (M V,RRab = 0.76 ± 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, M V,RRc = 0.27 ± 0.17). We find the bulk velocity of the halo relative to the Sun to be (W π , W θ , W z ) = (12.0, –209.9, 3.0) km s –1 in the radial, rotational, and vertical directions with dispersions (σ W π ,σ W θ ,σ W z ) = (150.4, 106.1, 96.0) km s -1 . For the disk, we find (W π , W θ , W z ) = (13.0, –42.0, –27.3) km s –1 relative to the Sun with dispersions (σ W π ,σ W θ ,σ W z ) = (67.7,59.2,54.9) km s -1 . Finally, as a byproduct of our statistical framework, we are able to demonstrate that UCAC2 proper-motion errors are significantly overestimated as verified by UCAC4

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

Science.gov (United States)

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

2015-04-14

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

Gaia Data Release 1. Testing the parallaxes with local Cepheids and RR Lyrae stars

OpenAIRE

Gaia Collaboration; Clementini, G.; Eyer, L.; Ripepi, V.; Marconi, M.; Muraveva, T.; Garofalo, A.; Sarro, L. M.; Palmer, M.; Luri, X.; Molinaro, R.; Rimoldini, L.; Szabados, L.; Musella, I.; Anderson, R. I.

2017-01-01

Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the HIPPARCOS and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims. In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, which involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with l...

The nature of parallax microlensing events towards the Galactic bulge

NARCIS (Netherlands)

Smith, MC; Belokurov, [No Value; Evans, NW; Mao, SD; An, JH

2005-01-01

Perhaps as many as 30 parallax microlensing events are known, thanks to the efforts of the Massive Compact Halo Object (MACHO), Optical Gravitational Lensing Experiment (OGLE), Experience pour la Recherche d'Objets Sombres (EROS) and Microlensing Observations in Astrophysics (MOA) experiments

LFQuant: a label-free fast quantitative analysis tool for high-resolution LC-MS/MS proteomics data.

Science.gov (United States)

Zhang, Wei; Zhang, Jiyang; Xu, Changming; Li, Ning; Liu, Hui; Ma, Jie; Zhu, Yunping; Xie, Hongwei

2012-12-01

Database searching based methods for label-free quantification aim to reconstruct the peptide extracted ion chromatogram based on the identification information, which can limit the search space and thus make the data processing much faster. The random effect of the MS/MS sampling can be remedied by cross-assignment among different runs. Here, we present a new label-free fast quantitative analysis tool, LFQuant, for high-resolution LC-MS/MS proteomics data based on database searching. It is designed to accept raw data in two common formats (mzXML and Thermo RAW), and database search results from mainstream tools (MASCOT, SEQUEST, and X!Tandem), as input data. LFQuant can handle large-scale label-free data with fractionation such as SDS-PAGE and 2D LC. It is easy to use and provides handy user interfaces for data loading, parameter setting, quantitative analysis, and quantitative data visualization. LFQuant was compared with two common quantification software packages, MaxQuant and IDEAL-Q, on the replication data set and the UPS1 standard data set. The results show that LFQuant performs better than them in terms of both precision and accuracy, and consumes significantly less processing time. LFQuant is freely available under the GNU General Public License v3.0 at http://sourceforge.net/projects/lfquant/. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-Resolution Adaptive Optics Test-Bed for Vision Science

International Nuclear Information System (INIS)

Wilks, S.C.; Thomspon, C.A.; Olivier, S.S.; Bauman, B.J.; Barnes, T.; Werner, J.S.

2001-01-01

We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed

Improved High Resolution Models of Subduction Dynamics: Use of transversely isotropic viscosity with a free-surface

Science.gov (United States)

Liu, X.; Gurnis, M.; Stadler, G.; Rudi, J.; Ratnaswamy, V.; Ghattas, O.

2017-12-01

Dynamic topography, or uncompensated topography, is controlled by internal dynamics, and provide constraints on the buoyancy structure and rheological parameters in the mantle. Compared with other surface manifestations such as the geoid, dynamic topography is very sensitive to shallower and more regional mantle structure. For example, the significant dynamic topography above the subduction zone potentially provides a rich mine for inferring the rheological and mechanical properties such as plate coupling, flow, and lateral viscosity variations, all critical in plate tectonics. However, employing subduction zone topography in the inversion study requires that we have a better understanding of the topography from forward models, especially the influence of the viscosity formulation, numerical resolution, and other factors. One common approach to formulating a fault between the subducted slab and the overriding plates in viscous flow models assumes a thin weak zone. However, due to the large lateral variation in viscosity, topography from free-slip numerical models typically has artificially large magnitude as well as high-frequency undulations over subduction zone, which adds to the difficulty in making comparisons between model results and observations. In this study, we formulate a weak zone with the transversely isotropic viscosity (TI) where the tangential viscosity is much smaller than the viscosity in the normal direction. Similar with isotropic weak zone models, TI models effectively decouple subducted slabs from the overriding plates. However, we find that the topography in TI models is largely reduced compared with that in weak zone models assuming an isotropic viscosity. Moreover, the artificial `tooth paste' squeezing effect observed in isotropic weak zone models vanishes in TI models, although the difference becomes less significant when the dip angle is small. We also implement a free-surface condition in our numerical models, which has a smoothing

Parallaxes of southern extremely cool objects (parsec). II. Spectroscopic follow-up and parallaxes of 52 targets

Energy Technology Data Exchange (ETDEWEB)

Marocco, F.; Andrei, A. H.; Jones, H. R. A.; Pinfield, D. J.; Clarke, J. R. A.; Lucas, P. W. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Smart, R. L.; Sozzetti, A.; Bucciarelli, B. [INAF/Osservatorio Astrofisico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese (Italy); Day-Jones, A. C. [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Penna, J. L. [Observatório Nacional/MCT, R. Gal. José Cristino 77, CEP20921-400 RJ (Brazil)

2013-12-01

We present near-infrared spectroscopy for 52 ultracool dwarfs, including two newly discovered late-M dwarfs, one new late-M subdwarf candidate, three new L, and four new T dwarfs. We also present parallaxes and proper motions for 21 of them. Four of the targets presented here have previous parallax measurements, while all the others are new values. This allow us to populate further the spectral sequence at early types (L0-L4). Combining the astrometric parameters with the new near-infrared spectroscopy presented here, we are able to investigate further the nature of some of the objects. In particular, we find that the peculiar blue L1 dwarf SDSS J133148.92–011651.4 is a metal-poor object, likely a member of the galactic thick disk. We discover a new M subdwarf candidate, 2MASS J20115649–6201127. We confirm the low-gravity nature of EROS-MP J0032–4405, DENIS-P J035726.9–441730, and 2MASS J22134491–2136079. We present two new metal-poor dwarfs: the L4pec 2MASS J19285196–4356256 and the M7pec SIPS2346–5928. We also determine the effective temperature and bolometric luminosity of the 21 targets with astrometric measurements, and we obtain a new polynomial relation between effective temperature and near-infrared spectral type. The new fit suggests a flattening of the sequence at the transition between M and L spectral types. This could be an effect of dust formation, which causes a more rapid evolution of the spectral features as a function of the effective temperature.

THE ABSOLUTE MAGNITUDE OF RRc VARIABLES FROM STATISTICAL PARALLAX

Energy Technology Data Exchange (ETDEWEB)

Kollmeier, Juna A.; Burns, Christopher R.; Thompson, Ian B.; Preston, George W.; Crane, Jeffrey D.; Madore, Barry F.; Morrell, Nidia; Prieto, José L.; Shectman, Stephen; Simon, Joshua D.; Villanueva, Edward [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Szczygieł, Dorota M.; Gould, Andrew [Department of Astronomy, The Ohio State University, 4051 McPherson Laboratory, Columbus, OH 43210 (United States); Sneden, Christopher [Department of Astronomy, University of Texas at Austin, TX 78712 (United States); Dong, Subo [Institute for Advanced Study, 500 Einstein Drive, Princeton, NJ 08540 (United States)

2013-09-20

We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 242 RRc variables selected from the All Sky Automated Survey for which high-quality light curves, photometry, and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey. We find that M{sub V,RRc} = 0.59 ± 0.10 at a mean metallicity of [Fe/H] = –1.59. This is to be compared with previous estimates for RRab stars (M{sub V,RRab} = 0.76 ± 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, M{sub V,RRc} = 0.27 ± 0.17). We find the bulk velocity of the halo relative to the Sun to be (W{sub π}, W{sub θ}, W{sub z} ) = (12.0, –209.9, 3.0) km s{sup –1} in the radial, rotational, and vertical directions with dispersions (σ{sub W{sub π}},σ{sub W{sub θ}},σ{sub W{sub z}}) = (150.4, 106.1, 96.0) km s{sup -1}. For the disk, we find (W{sub π}, W{sub θ}, W{sub z} ) = (13.0, –42.0, –27.3) km s{sup –1} relative to the Sun with dispersions (σ{sub W{sub π}},σ{sub W{sub θ}},σ{sub W{sub z}}) = (67.7,59.2,54.9) km s{sup -1}. Finally, as a byproduct of our statistical framework, we are able to demonstrate that UCAC2 proper-motion errors are significantly overestimated as verified by UCAC4.

Parallax visualization of full motion video using the Pursuer GUI

Science.gov (United States)

Mayhew, Christopher A.; Forgues, Mark B.

2014-06-01

In 2013, the Authors reported to the SPIE on the Phase 1 development of a Parallax Visualization (PV) plug-in toolset for Wide Area Motion Imaging (WAMI) data using the Pursuer Graphical User Interface (GUI).1 In addition to the ability to PV WAMI data, the Phase 1 plug-in toolset also featured a limited ability to visualize Full Motion video (FMV) data. The ability to visualize both WAMI and FMV data is highly advantageous capability for an Electric Light Table (ELT) toolset. This paper reports on the Phase 2 development and addition of a full featured FMV capability to the Pursuer WAMI PV Plug-in.

Gaia Data Release 1. Testing parallaxes with local Cepheids and RR Lyrae stars

Science.gov (United States)

Gaia Collaboration; Clementini, G.; Eyer, L.; Ripepi, V.; Marconi, M.; Muraveva, T.; Garofalo, A.; Sarro, L. M.; Palmer, M.; Luri, X.; Molinaro, R.; Rimoldini, L.; Szabados, L.; Musella, I.; Anderson, R. I.; Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A.; Vallenari, A.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; van Leeuwen, F.; Walton, N. A.; Aerts, C.; Arenou, F.; Cropper, M.; Drimmel, R.; Høg, E.; Katz, D.; Lattanzi, M. G.; O'Mullane, W.; Grebel, E. K.; Holland, A. D.; Huc, C.; Passot, X.; Perryman, M.; Bramante, L.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Hernández, J.; Jean-Antoine-Piccolo, A.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Ordóñez-Blanco, D.; Panuzzo, P.; Portell, J.; Richards, P. J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Torra, J.; Els, S. G.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Lock, T.; Mercier, E.; Altmann, M.; Andrae, R.; Astraatmadja, T. L.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Busso, G.; Carry, B.; Cellino, A.; Cowell, S.; Creevey, O.; Cuypers, J.; Davidson, M.; De Ridder, J.; de Torres, A.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Frémat, Y.; García-Torres, M.; Gosset, E.; Halbwachs, J.-L.; Hambly, N. C.; Harrison, D. L.; Hauser, M.; Hestroffer, D.; Hodgkin, S. T.; Huckle, H. E.; Hutton, A.; Jasniewicz, G.; Jordan, S.; Kontizas, M.; Korn, A. J.; Lanzafame, A. C.; Manteiga, M.; Moitinho, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J.-M.; Recio-Blanco, A.; Robin, A. C.; Siopis, C.; Smith, M.; Smith, K. W.; Sozzetti, A.; Thuillot, W.; van Reeven, W.; Viala, Y.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aguado, J. J.; Allan, P. M.; Allasia, W.; Altavilla, G.; Álvarez, M. A.; Alves, J.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Antón, S.; Arcay, B.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Barache, C.; Barata, C.; Barbier, A.; Barblan, F.; Barrado y Navascués, D.; Barros, M.; Barstow, M. A.; Becciani, U.; Bellazzini, M.; Bello García, A.; Belokurov, V.; Bendjoya, P.; Berihuete, A.; Bianchi, L.; Bienaymé, O.; Billebaud, F.; Blagorodnova, N.; Blanco-Cuaresma, S.; Boch, T.; Bombrun, A.; Borrachero, R.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Breddels, M. A.; Brouillet, N.; Brüsemeister, T.; Bucciarelli, B.; Burgess, P.; Burgon, R.; Burlacu, A.; Busonero, D.; Buzzi, R.; Caffau, E.; Cambras, J.; Campbell, H.; Cancelliere, R.; Cantat-Gaudin, T.; Carlucci, T.; Carrasco, J. M.; Castellani, M.; Charlot, P.; Charnas, J.; Chiavassa, A.; Clotet, M.; Cocozza, G.; Collins, R. S.; Costigan, G.; Crifo, F.; Cross, N. J. G.; Crosta, M.; Crowley, C.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; De Cat, P.; de Felice, F.; de Laverny, P.; De Luise, F.; De March, R.; de Souza, R.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Distefano, E.; Dolding, C.; Dos Anjos, S.; Drazinos, P.; Durán, J.; Dzigan, Y.; Edvardsson, B.; Enke, H.; Evans, N. W.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernández-Hernández, J.; Fernique, P.; Fienga, A.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fouesneau, M.; Fraile, E.; Fraser, M.; Fuchs, J.; Gai, M.; Galleti, S.; Galluccio, L.; Garabato, D.; García-Sedano, F.; Garralda, N.; Gavras, P.; Gerssen, J.; Geyer, R.; Gilmore, G.; Girona, S.; Giuffrida, G.; Gomes, M.; González-Marcos, A.; González-Núñez, J.; González-Vidal, J. J.; Granvik, M.; Guerrier, A.; Guillout, P.; Guiraud, J.; Gúrpide, A.; Gutiérrez-Sánchez, R.; Guy, L. P.; Haigron, R.; Hatzidimitriou, D.; Haywood, M.; Heiter, U.; Helmi, A.; Hobbs, D.; Hofmann, W.; Holl, B.; Holland, G.; Hunt, J. A. S.; Hypki, A.; Icardi, V.; Irwin, M.; Jevardat de Fombelle, G.; Jofré, P.; Jonker, P. G.; Jorissen, A.; Julbe, F.; Karampelas, A.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Koubsky, P.; Krone-Martins, A.; Kudryashova, M.; Bachchan, R. K.; Lacoste-Seris, F.; Lanza, A. F.; Lavigne, J.-B.; Le Poncin-Lafitte, C.; Lebreton, Y.; Lebzelter, T.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lemaitre, V.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; Löffler, W.; López, M.; Lorenz, D.; MacDonald, I.; Magalhães Fernandes, T.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marinoni, S.; Marrese, P. M.; Marschalkó, G.; Marshall, D. J.; Martín-Fleitas, J. M.; Martino, M.; Mary, N.; Matijevič, G.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Miranda, B. M. H.; Molina, D.; Molinaro, M.; Molnár, L.; Moniez, M.; Montegriffo, P.; Mor, R.; Mora, A.; Morbidelli, R.; Morel, T.; Morgenthaler, S.; Morris, D.; Mulone, A. F.; Narbonne, J.; Nelemans, G.; Nicastro, L.; Noval, L.; Ordénovic, C.; Ordieres-Meré, J.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Parsons, P.; Pecoraro, M.; Pedrosa, R.; Pentikäinen, H.; Pichon, B.; Piersimoni, A. M.; Pineau, F.-X.; Plachy, E.; Plum, G.; Poujoulet, E.; Prša, A.; Pulone, L.; Ragaini, S.; Rago, S.; Rambaux, N.; Ramos-Lerate, M.; Ranalli, P.; Rauw, G.; Read, A.; Regibo, S.; Reylé, C.; Ribeiro, R. A.; Riva, A.; Rixon, G.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Segransan, D.; Shih, I.-C.; Smareglia, R.; Smart, R. L.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Süveges, M.; Surdej, J.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Tingley, B.; Trager, S. C.; Turon, C.; Ulla, A.; Utrilla, E.; Valentini, G.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Varadi, M.; Vecchiato, A.; Veljanoski, J.; Via, T.; Vicente, D.; Vogt, S.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Weingrill, K.; Wevers, T.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Zucker, S.; Zurbach, C.; Zwitter, T.; Alecu, A.; Allen, M.; Allende Prieto, C.; Amorim, A.; Anglada-Escudé, G.; Arsenijevic, V.; Azaz, S.; Balm, P.; Beck, M.; Bernstein, H.-H.; Bigot, L.; Bijaoui, A.; Blasco, C.; Bonfigli, M.; Bono, G.; Boudreault, S.; Bressan, A.; Brown, S.; Brunet, P.-M.; Bunclark, P.; Buonanno, R.; Butkevich, A. G.; Carret, C.; Carrion, C.; Chemin, L.; Chéreau, F.; Corcione, L.; Darmigny, E.; de Boer, K. S.; de Teodoro, P.; de Zeeuw, P. T.; Delle Luche, C.; Domingues, C. D.; Dubath, P.; Fodor, F.; Frézouls, B.; Fries, A.; Fustes, D.; Fyfe, D.; Gallardo, E.; Gallegos, J.; Gardiol, D.; Gebran, M.; Gomboc, A.; Gómez, A.; Grux, E.; Gueguen, A.; Heyrovsky, A.; Hoar, J.; Iannicola, G.; Isasi Parache, Y.; Janotto, A.-M.; Joliet, E.; Jonckheere, A.; Keil, R.; Kim, D.-W.; Klagyivik, P.; Klar, J.; Knude, J.; Kochukhov, O.; Kolka, I.; Kos, J.; Kutka, A.; Lainey, V.; LeBouquin, D.; Liu, C.; Loreggia, D.; Makarov, V. V.; Marseille, M. G.; Martayan, C.; Martinez-Rubi, O.; Massart, B.; Meynadier, F.; Mignot, S.; Munari, U.; Nguyen, A.-T.; Nordlander, T.; O'Flaherty, K. S.; Ocvirk, P.; Olias Sanz, A.; Ortiz, P.; Osorio, J.; Oszkiewicz, D.; Ouzounis, A.; Park, P.; Pasquato, E.; Peltzer, C.; Peralta, J.; Péturaud, F.; Pieniluoma, T.; Pigozzi, E.; Poels, J.; Prat, G.; Prod'homme, T.; Raison, F.; Rebordao, J. M.; Risquez, D.; Rocca-Volmerange, B.; Rosen, S.; Ruiz-Fuertes, M. I.; Russo, F.; Serraller Vizcaino, I.; Short, A.; Siebert, A.; Silva, H.; Sinachopoulos, D.; Slezak, E.; Soffel, M.; Sosnowska, D.; Straižys, V.; ter Linden, M.; Terrell, D.; Theil, S.; Tiede, C.; Troisi, L.; Tsalmantza, P.; Tur, D.; Vaccari, M.; Vachier, F.; Valles, P.; Van Hamme, W.; Veltz, L.; Virtanen, J.; Wallut, J.-M.; Wichmann, R.; Wilkinson, M. I.; Ziaeepour, H.; Zschocke, S.

2017-09-01

Context. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). Aims: In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, which involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with literature estimates and derived new period-luminosity (PL), period-Wesenheit (PW) relations for classical and Type II Cepheids and infrared PL, PL-metallicity (PLZ), and optical luminosity-metallicity (MV-[Fe/H]) relations for the RR Lyrae stars, with zero points based on TGAS. Methods: Classical Cepheids were carefully selected in order to discard known or suspected binary systems. The final sample comprises 102 fundamental mode pulsators with periods ranging from 1.68 to 51.66 days (of which 33 with σϖ/ϖimpressive. Conclusions: TGAS parallaxes bring a significant added value to the previous Hipparcos estimates. The relations presented in this paper represent the first Gaia-calibrated relations and form a work-in-progress milestone report in the wait for Gaia-only parallaxes of which a first solution will become available with Gaia Data Release 2 (DR2) in 2018. Full Tables A.1-A.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/A79

Parallax barrier engineering for image quality improvement in an autostereoscopic 3D display.

Science.gov (United States)

Kim, Sung-Kyu; Yoon, Ki-Hyuk; Yoon, Seon Kyu; Ju, Heongkyu

2015-05-18

We present a image quality improvement in a parallax barrier (PB)-based multiview autostereoscopic 3D display system under a real-time tracking of positions of a viewer's eyes. The system presented exploits a parallax barrier engineered to offer significantly improved quality of three-dimensional images for a moving viewer without an eyewear under the dynamic eye tracking. The improved image quality includes enhanced uniformity of image brightness, reduced point crosstalk, and no pseudoscopic effects. We control the relative ratio between two parameters i.e., a pixel size and the aperture of a parallax barrier slit to improve uniformity of image brightness at a viewing zone. The eye tracking that monitors positions of a viewer's eyes enables pixel data control software to turn on only pixels for view images near the viewer's eyes (the other pixels turned off), thus reducing point crosstalk. The eye tracking combined software provides right images for the respective eyes, therefore producing no pseudoscopic effects at its zone boundaries. The viewing zone can be spanned over area larger than the central viewing zone offered by a conventional PB-based multiview autostereoscopic 3D display (no eye tracking). Our 3D display system also provides multiviews for motion parallax under eye tracking. More importantly, we demonstrate substantial reduction of point crosstalk of images at the viewing zone, its level being comparable to that of a commercialized eyewear-assisted 3D display system. The multiview autostereoscopic 3D display presented can greatly resolve the point crosstalk problem, which is one of the critical factors that make it difficult for previous technologies for a multiview autostereoscopic 3D display to replace an eyewear-assisted counterpart.

A comparison of Hipparcos parallaxes with planetary nebulae spectroscopic distances

NARCIS (Netherlands)

Pottasch, [No Value; Acker, A

1998-01-01

The Hipparcos satellite has measured the parallax of a small sample of planetary nebulae. In this paper we consider the results for 3 planetary nebulae (PN) for which spectroscopic distances have also been determined from stellar gravities. These gravities in turn have been derived from profile

Image Registration Algorithm Based on Parallax Constraint and Clustering Analysis

Science.gov (United States)

Wang, Zhe; Dong, Min; Mu, Xiaomin; Wang, Song

2018-01-01

To resolve the problem of slow computation speed and low matching accuracy in image registration, a new image registration algorithm based on parallax constraint and clustering analysis is proposed. Firstly, Harris corner detection algorithm is used to extract the feature points of two images. Secondly, use Normalized Cross Correlation (NCC) function to perform the approximate matching of feature points, and the initial feature pair is obtained. Then, according to the parallax constraint condition, the initial feature pair is preprocessed by K-means clustering algorithm, which is used to remove the feature point pairs with obvious errors in the approximate matching process. Finally, adopt Random Sample Consensus (RANSAC) algorithm to optimize the feature points to obtain the final feature point matching result, and the fast and accurate image registration is realized. The experimental results show that the image registration algorithm proposed in this paper can improve the accuracy of the image matching while ensuring the real-time performance of the algorithm.

Picometer-resolution dual-comb spectroscopy with a free-running fiber laser.

Science.gov (United States)

Zhao, Xin; Hu, Guoqing; Zhao, Bofeng; Li, Cui; Pan, Yingling; Liu, Ya; Yasui, Takeshi; Zheng, Zheng

2016-09-19

Dual-comb spectroscopy holds the promise as real-time, high-resolution spectroscopy tools. However, in its conventional schemes, the stringent requirement on the coherence between two lasers requires sophisticated control systems. By replacing control electronics with an all-optical dual-comb lasing scheme, a simplified dual-comb spectroscopy scheme is demonstrated using one dual-wavelength, passively mode-locked fiber laser. Pulses with a intracavity-dispersion-determined repetition-frequency difference are shown to have good mutual coherence and stability. Capability to resolve the comb teeth and a picometer-wide optical spectral resolution are demonstrated using a simple data acquisition system. Energy-efficient, free-running fiber lasers with a small comb-tooth-spacing could enable low-cost dual-comb systems.

Coma-free alignment of high resolution electron microscopes with the aid of optical diffractograms

International Nuclear Information System (INIS)

Zemlin, F.; Weiss, K.; Schiske, P.; Kunath, W.; Herrmann, K.-H.

1978-01-01

Alignment by means of current commutating and defocusing of the objective does not yield the desired rotational symmetry of the imaging pencils. This was found while aligning a transmission electron microscope with a single field condenser objective. A series of optical diffractograms of micrographs taken under the same tilted illumination yet under various azimuths have been arranged in a tableau, wherein strong asymmetry is exhibited. Quantitative evaluation yields the most important asymmetric aberration to be the axial coma, which becomes critical when a resolution better than 5 A 0 is obtained. The tableau also allows an assessment of the three-fold astigmatism. A procedure has been developed which aligns the microscope onto the coma-free and dispersion-free pencil axis and does not rely on current communication. The procedure demands equal appearance of astigmatic carbon film images produced under the same tilt yet diametrical azimuth. (Auth.)

High spatial resolution free-breathing 3D late gadolinium enhancement cardiac magnetic resonance imaging in ischaemic and non-ischaemic cardiomyopathy: quantitative assessment of scar mass and image quality.

Science.gov (United States)

Bizino, Maurice B; Tao, Qian; Amersfoort, Jacob; Siebelink, Hans-Marc J; van den Bogaard, Pieter J; van der Geest, Rob J; Lamb, Hildo J

2018-04-06

To compare breath-hold (BH) with navigated free-breathing (FB) 3D late gadolinium enhancement cardiac MRI (LGE-CMR) MATERIALS AND METHODS: Fifty-one patients were retrospectively included (34 ischaemic cardiomyopathy, 14 non-ischaemic cardiomyopathy, three discarded). BH and FB 3D phase sensitive inversion recovery sequences were performed at 3T. FB datasets were reformatted into normal resolution (FB-NR, 1.46x1.46x10mm) and high resolution (FB-HR, isotropic 0.91-mm voxels). Scar mass, scar edge sharpness (SES), SNR and CNR were compared using paired-samples t-test, Pearson correlation and Bland-Altman analysis. Scar mass was similar in BH and FB-NR (mean ± SD: 15.5±18.0 g vs. 15.5±16.9 g, p=0.997), with good correlation (r=0.953), and no bias (mean difference ± SD: 0.00±5.47 g). FB-NR significantly overestimated scar mass compared with FB-HR (15.5±16.9 g vs 14.4±15.6 g; p=0.007). FB-NR and FB-HR correlated well (r=0.988), but Bland-Altman demonstrated systematic bias (1.15±2.84 g). SES was similar in BH and FB-NR (p=0.947), but significantly higher in FB-HR than FB-NR (pFB-NR (pFB-HR than FB-NR (p<0.01). Navigated free-breathing 3D LGE-CMR allows reliable scar mass quantification comparable to breath-hold. During free-breathing, spatial resolution can be increased resulting in improved sharpness and reduced scar mass. • Navigated free-breathing 3D late gadolinium enhancement is reliable for myocardial scar quantification. • High-resolution 3D late gadolinium enhancement increases scar sharpness • Ischaemic and non-ischaemic cardiomyopathy patients can be imaged using free-breathing LGE CMR.

Testing parallaxes with local Cepheids and RR Lyrae stars

Czech Academy of Sciences Publication Activity Database

Clementini, G.; Eyer, L.; Ripepi, V.; Marconi, M.; Muraveva, T.; Garofalo, A.; Sarro, L.M.; Palmer, M.; Luri, X.; Koubský, Pavel; Votruba, Viktor

2017-01-01

Roč. 605, September (2017), A79/1-A79/29 E-ISSN 1432-0746 R&D Projects: GA MŠk(CZ) LG15010 Grant - others:ESA(XE) ESA-PECS project no. 98058 Institutional support: RVO:67985815 Keywords : astrometry * parallaxes * stars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample

International Nuclear Information System (INIS)

Subasavage, John P.; Harris, Hugh C.; Dahn, Conard C.; Jao, Wei-Chun; Lépine, Sébastien; Henry, Todd J.; Ianna, Philip A.; Bergeron, P.; Dufour, P.; Dunlap, Bart H.; Barlow, Brad N.; Margheim, Steven J.

2017-01-01

We present 114 trigonometric parallaxes for 107 nearby white dwarf (WD) systems from both the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI) and the U. S. Naval Observatory Flagstaff Station (NOFS) parallax programs. Of these, 76 parallaxes for 69 systems were measured by the CTIOPI program and 38 parallaxes for as many systems were measured by the NOFS program. A total of 50 systems are confirmed to be within the 25-pc horizon of interest. Coupled with a spectroscopic confirmation of a common proper-motion companion to a Hipparcos star within 25 pc as well as confirmation parallax determinations for two WD systems included in the recently released Tycho Gaia Astrometric Solution catalog, we add 53 new systems to the 25-pc WD sample—a 42% increase. Our sample presented here includes four strong candidate halo systems, a new metal-rich DAZ WD, a confirmation of a recently discovered nearby short-period ( P  = 2.85 hr) double degenerate, a WD with a new astrometric perturbation (long period, unconstrained with our data), and a new triple system where the WD companion main-sequence star has an astrometric perturbation ( P  ∼ 1.6 year).

The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample

Energy Technology Data Exchange (ETDEWEB)

Subasavage, John P.; Harris, Hugh C.; Dahn, Conard C. [U.S. Naval Observatory, 10391 West Naval Observatory Road, Flagstaff, AZ 86005-8521 (United States); Jao, Wei-Chun; Lépine, Sébastien [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302-4106 (United States); Henry, Todd J.; Ianna, Philip A. [RECONS Institute, Chambersburg, PA 17201 (United States); Bergeron, P.; Dufour, P. [Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7 (Canada); Dunlap, Bart H. [University of North Carolina at Chapel Hill, Dept. of Physics and Astronomy, Chapel Hill, NC 27599 (United States); Barlow, Brad N. [Department of Physics, High Point University, One University Parkway, High Point, NC 27268 (United States); Margheim, Steven J., E-mail: jsubasavage@nofs.navy.mil [Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile)

2017-07-01

We present 114 trigonometric parallaxes for 107 nearby white dwarf (WD) systems from both the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI) and the U. S. Naval Observatory Flagstaff Station (NOFS) parallax programs. Of these, 76 parallaxes for 69 systems were measured by the CTIOPI program and 38 parallaxes for as many systems were measured by the NOFS program. A total of 50 systems are confirmed to be within the 25-pc horizon of interest. Coupled with a spectroscopic confirmation of a common proper-motion companion to a Hipparcos star within 25 pc as well as confirmation parallax determinations for two WD systems included in the recently released Tycho Gaia Astrometric Solution catalog, we add 53 new systems to the 25-pc WD sample—a 42% increase. Our sample presented here includes four strong candidate halo systems, a new metal-rich DAZ WD, a confirmation of a recently discovered nearby short-period ( P  = 2.85 hr) double degenerate, a WD with a new astrometric perturbation (long period, unconstrained with our data), and a new triple system where the WD companion main-sequence star has an astrometric perturbation ( P  ∼ 1.6 year).

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

Directory of Open Access Journals (Sweden)

Vamsi Kiran Adhikarla

2015-04-01

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

The Parallax of the Red Hypergiant VX Sgr with Accurate Tropospheric Delay Calibration

Science.gov (United States)

Xu, Shuangjing; Zhang, Bo; Reid, Mark J.; Menten, Karl M.; Zheng, Xingwu; Wang, Guangli

2018-05-01

We report astrometric results of VLBI phase-referencing observations of 22 GHz H2O masers emission toward the red hypergiant VX Sgr, one of most massive and luminous red hypergiant stars in our Galaxy, using the Very Long Baseline Array. A background source, J1820‑2528, projected 4.°4 from the target VX Sgr, was used as the phase reference. For the low decl. of these sources, such a large separation normally would seriously degrade the relative astrometry. We use a two-step method of tropospheric delay calibration, which combines the VLBI geodetic-block (or Global Positioning System) calibration with an image-optimization calibration, to obtain a trigonometric parallax of 0.64 ± 0.04 mas, corresponding to a distance of {1.56}-0.10+0.11 kpc. The measured proper motion of VX Sgr is 0.36 ± 0.76 and ‑2.92 ± 0.78 mas yr‑1 in the eastward and northward directions. The parallax and proper motion confirms that VX Sgr belong to the Sgr OB1 association. Rescaling bolometric luminosities in the literature to our parallax distance, we find that the luminosity of VX Sgr is (1.95 ± 0.62) × 105 L ⊙, where the uncertainty is dominated by differing photometry measurements.

TRIGONOMETRIC PARALLAXES AND PROPER MOTIONS OF 134 SOUTHERN LATE M, L, AND T DWARFS FROM THE CARNEGIE ASTROMETRIC PLANET SEARCH PROGRAM

Energy Technology Data Exchange (ETDEWEB)

Weinberger, Alycia J.; Boss, Alan P.; Keiser, Sandra A. [Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Anglada-Escudé, Guillem [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London, E1 4NS (United Kingdom); Thompson, Ian B. [Carnegie Observatories, Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101-1292 (United States); Burley, Gregory [National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)

2016-07-01

We report trigonometric parallaxes for 134 low-mass stars and brown dwarfs, of which 38 have no previously published measurement and 79 more have improved uncertainties. Our survey focused on nearby targets, so 119 are closer than 30 pc. Of the 38 stars with new parallaxes, 14 are within 20 pc and seven are likely brown dwarfs (spectral types later than L0). These parallaxes are useful for studies of kinematics, multiplicity, and spectrophotometric calibration. Two objects with new parallaxes are confirmed as young stars with membership in nearby young moving groups: LP 870-65 in AB Doradus and G 161-71 in Argus. We also report the first parallax for the planet-hosting star GJ 3470; this allows us to refine the density of its Neptune-mass planet. T-dwarf 2MASS J12590470-4336243, previously thought to lie within 4 pc, is found to be at 7.8 pc, and the M-type star 2MASS J01392170-3936088 joins the ranks of nearby stars as it is found to be within 10 pc. Five stars that are overluminous and/or too red for their spectral types are identified and deserve further study as possible young stars.

TRIGONOMETRIC PARALLAXES AND PROPER MOTIONS OF 134 SOUTHERN LATE M, L, AND T DWARFS FROM THE CARNEGIE ASTROMETRIC PLANET SEARCH PROGRAM

International Nuclear Information System (INIS)

Weinberger, Alycia J.; Boss, Alan P.; Keiser, Sandra A.; Anglada-Escudé, Guillem; Thompson, Ian B.; Burley, Gregory

2016-01-01

We report trigonometric parallaxes for 134 low-mass stars and brown dwarfs, of which 38 have no previously published measurement and 79 more have improved uncertainties. Our survey focused on nearby targets, so 119 are closer than 30 pc. Of the 38 stars with new parallaxes, 14 are within 20 pc and seven are likely brown dwarfs (spectral types later than L0). These parallaxes are useful for studies of kinematics, multiplicity, and spectrophotometric calibration. Two objects with new parallaxes are confirmed as young stars with membership in nearby young moving groups: LP 870-65 in AB Doradus and G 161-71 in Argus. We also report the first parallax for the planet-hosting star GJ 3470; this allows us to refine the density of its Neptune-mass planet. T-dwarf 2MASS J12590470-4336243, previously thought to lie within 4 pc, is found to be at 7.8 pc, and the M-type star 2MASS J01392170-3936088 joins the ranks of nearby stars as it is found to be within 10 pc. Five stars that are overluminous and/or too red for their spectral types are identified and deserve further study as possible young stars.

High-resolution structure of the native histone octamer

International Nuclear Information System (INIS)

Wood, Christopher M.; Nicholson, James M.; Lambert, Stanley J.; Chantalat, Laurent; Reynolds, Colin D.; Baldwin, John P.

2005-01-01

The high-resolution (1.90 Å) model of the native histone octamer allows structural comparisons to be made with the nucleosome-core particle, along with an identification of a likely core-histone binding site. Crystals of native histone octamers (H2A–H2B)–(H4–H3)–(H3′–H4′)–(H2B′–H2A′) from chick erythrocytes in 2 M KCl, 1.35 M potassium phosphate pH 6.9 diffract X-rays to 1.90 Å resolution, yielding a structure with an R work value of 18.7% and an R free of 22.2%. The crystal space group is P6 5 , the asymmetric unit of which contains one complete octamer. This high-resolution model of the histone-core octamer allows further insight into intermolecular interactions, including water molecules, that dock the histone dimers to the tetramer in the nucleosome-core particle and have relevance to nucleosome remodelling. The three key areas analysed are the H2A′–H3–H4 molecular cluster (also H2A–H3′–H4′), the H4–H2B′ interaction (also H4′–H2B) and the H2A′–H4 β-sheet interaction (also H2A–H4′). The latter of these three regions is important to nucleosome remodelling by RNA polymerase II, as it is shown to be a likely core-histone binding site, and its disruption creates an instability in the nucleosome-core particle. A majority of the water molecules in the high-resolution octamer have positions that correlate to similar positions in the high-resolution nucleosome-core particle structure, suggesting that the high-resolution octamer model can be used for comparative studies with the high-resolution nucleosome-core particle

THE HAWAII INFRARED PARALLAX PROGRAM. II. YOUNG ULTRACOOL FIELD DWARFS

Energy Technology Data Exchange (ETDEWEB)

Liu, Michael C. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Dupuy, Trent J. [The University of Texas at Austin, Department of Astronomy, 2515 Speedway C1400, Austin, TX 78712 (United States); Allers, Katelyn N., E-mail: mliu@ifa.hawaii.edu [Department of Physics and Astronomy, Bucknell University, Lewisburg, PA 17837 (United States)

2016-12-10

We present a large, uniform analysis of young (≈10–150 Myr) ultracool dwarfs, based on new high-precision infrared (IR) parallaxes for 68 objects. We find that low-gravity (vl-g) late-M and L dwarfs form a continuous sequence in IR color–magnitude diagrams, separate from the field population and from current theoretical models. These vl-g objects also appear distinct from young substellar (brown dwarf and exoplanet) companions, suggesting that the two populations may have a different range of physical properties. In contrast, at the L/T transition, young, old, and spectrally peculiar objects all span a relatively narrow range in near-IR absolute magnitudes. At a given spectral type, the IR absolute magnitudes of young objects can be offset from ordinary field dwarfs, with the largest offsets occurring in the Y and J bands for late-M dwarfs (brighter than the field) and mid-/late-L dwarfs (fainter than the field). Overall, low-gravity (vl-g) objects have the most uniform photometric behavior, while intermediate gravity (int-g) objects are more diverse, suggesting a third governing parameter beyond spectral type and gravity class. We examine the moving group membership for all young ultracool dwarfs with parallaxes, changing the status of 23 objects (including 8 previously identified planetary-mass candidates) and fortifying the status of another 28 objects. We use our resulting age-calibrated sample to establish empirical young isochrones and show a declining frequency of vl-g objects relative to int-g objects with increasing age. Notable individual objects in our sample include high-velocity (≳100 km s{sup −1}) int-g objects, very red late-L dwarfs with high surface gravities, candidate disk-bearing members of the MBM20 cloud and β  Pic moving group, and very young distant interlopers. Finally, we provide a comprehensive summary of the absolute magnitudes and spectral classifications of young ultracool dwarfs, using a combined sample of 102�

DISTANCE AND KINEMATICS OF THE TW HYDRAE ASSOCIATION FROM PARALLAXES

Energy Technology Data Exchange (ETDEWEB)

Weinberger, Alycia J.; Boss, Alan P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Anglada-Escude, Guillem, E-mail: weinberger@dtm.ciw.edu [Institut fuer Astrophysik, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

2013-01-10

From common proper motion and signatures of youth, researchers have identified about 30 members of a putative TW Hydrae Association. Only four of these had parallactic distances from Hipparcos. We have measured parallaxes and proper motions for 14 primary members. We combine these with literature values of radial velocities to show that the Galactic space motions of the stars, with the exception of TWA 9 and 22, are parallel and do not indicate convergence at a common formation point sometime in the last few million years. The space motions of TWA 9 and 22 do not agree with the others and indicate that they are not TWA members. The median parallax is 18 mas or 56 pc. We further analyze the stars' absolute magnitudes on pre-main-sequence evolutionary tracks and find a range of ages with a median of 10.1 Myr and no correlation between age and Galactic location. The TWA stars may have formed from an extended and filamentary molecular cloud but are not necessarily precisely coeval.

KEPLER-LIKE MULTI-PLEXING FOR MASS PRODUCTION OF MICROLENS PARALLAXES

Energy Technology Data Exchange (ETDEWEB)

Gould, Andrew [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Horne, Keith, E-mail: gould@astronomy.ohio-state.edu, E-mail: kdh1@st-andrews.ac.uk [SUPA, University of St Andrews, School of Physics and Astronomy, North Haugh, St Andrews, KY16 9SS (United Kingdom)

2013-12-20

We show that a wide-field Kepler-like satellite in solar orbit could obtain microlens parallaxes for several thousand events per year that are identified from the ground, yielding masses and distances for several dozen planetary events. This is roughly an order of magnitude larger than previously considered narrow-angle designs. Such a satellite would, in addition, roughly double the number of planet detections (and mass/distance determinations). It would also yield a trove of brown-dwarf binaries with masses, distances, and (frequently) full orbits, enable new probes of the stellar mass function, and identify isolated black-hole candidates. We show that the actual Kepler satellite, even with degraded pointing, can demonstrate these capabilities and make substantial initial inroads into the science potential. We discuss several ''Deltas'' to the Kepler satellite aimed at optimizing microlens parallax capabilities. Most of these would reduce costs. The wide-angle approach advocated here has only recently become superior to the old narrow-angle approach, due to the much larger number of ground-based microlensing events now being discovered.

KEPLER-LIKE MULTI-PLEXING FOR MASS PRODUCTION OF MICROLENS PARALLAXES

International Nuclear Information System (INIS)

Gould, Andrew; Horne, Keith

2013-01-01

We show that a wide-field Kepler-like satellite in solar orbit could obtain microlens parallaxes for several thousand events per year that are identified from the ground, yielding masses and distances for several dozen planetary events. This is roughly an order of magnitude larger than previously considered narrow-angle designs. Such a satellite would, in addition, roughly double the number of planet detections (and mass/distance determinations). It would also yield a trove of brown-dwarf binaries with masses, distances, and (frequently) full orbits, enable new probes of the stellar mass function, and identify isolated black-hole candidates. We show that the actual Kepler satellite, even with degraded pointing, can demonstrate these capabilities and make substantial initial inroads into the science potential. We discuss several ''Deltas'' to the Kepler satellite aimed at optimizing microlens parallax capabilities. Most of these would reduce costs. The wide-angle approach advocated here has only recently become superior to the old narrow-angle approach, due to the much larger number of ground-based microlensing events now being discovered

Kepler-like Multi-plexing for Mass Production of Microlens Parallaxes

Science.gov (United States)

Gould, Andrew; Horne, Keith

2013-12-01

We show that a wide-field Kepler-like satellite in solar orbit could obtain microlens parallaxes for several thousand events per year that are identified from the ground, yielding masses and distances for several dozen planetary events. This is roughly an order of magnitude larger than previously considered narrow-angle designs. Such a satellite would, in addition, roughly double the number of planet detections (and mass/distance determinations). It would also yield a trove of brown-dwarf binaries with masses, distances, and (frequently) full orbits, enable new probes of the stellar mass function, and identify isolated black-hole candidates. We show that the actual Kepler satellite, even with degraded pointing, can demonstrate these capabilities and make substantial initial inroads into the science potential. We discuss several "Deltas" to the Kepler satellite aimed at optimizing microlens parallax capabilities. Most of these would reduce costs. The wide-angle approach advocated here has only recently become superior to the old narrow-angle approach, due to the much larger number of ground-based microlensing events now being discovered.

Exploring the η Aquila System: Another Cepheid Parallax and Further Evidence for a Tertiary

Science.gov (United States)

Benedict, George Frederick; Barnes, Thomas G.; Evans, Nancy; Cochran, William; McArthur, Barbara E.; Harrison, Thomas E.

2018-01-01

We report progress towards a re-analysis of Hubble Space Telescope Fine Guidance Sensor astrometric data, originally acquired to determine a parallax for and absolute magnitudes of the classical Cepheid, η Aquila. This object was not included in past Cepheid Period-Luminosity Relation (PLR) work (Benedict et al. 2007, AJ, 133, 1810), because we had an insufficient number of epochs with which to establish a suspected and complicating companion orbit. Our new investigation is considerably aided by including a significant number of radial velocity measures (RV) from six sources, including new, high-quality Hobby-Eberly Telescope spectra. We first derive a 12 Fourier coefficient description of the Cepheid pulsation, solving for velocity offsets required to bring the six RV data sets into coincidence. We next model the RV residuals to that fit with an orbit. The resulting orbit has very high eccentricity. The astrometric residuals show only a very small perturbation, consistent with a prediction from the spectroscopic orbit. We finally include that orbit in a combined astrometry and radial velocity model. This modeling, similar to that presented in Benedict and Harrison (2017, AJ, 153, 258) yields a parallax, allowing inclusion of η Aquila in a PLR. It also establishes a Cepheid/companion mass ratio for the early-type star companion identified in IUE spectra (Evans 1991, ApJ, 372, 597).

Improved Resolution Optical Time Stretch Imaging Based on High Efficiency In-Fiber Diffraction.

Science.gov (United States)

Wang, Guoqing; Yan, Zhijun; Yang, Lei; Zhang, Lin; Wang, Chao

2018-01-12

Most overlooked challenges in ultrafast optical time stretch imaging (OTSI) are sacrificed spatial resolution and higher optical loss. These challenges are originated from optical diffraction devices used in OTSI, which encode image into spectra of ultrashort optical pulses. Conventional free-space diffraction gratings, as widely used in existing OTSI systems, suffer from several inherent drawbacks: limited diffraction efficiency in a non-Littrow configuration due to inherent zeroth-order reflection, high coupling loss between free-space gratings and optical fibers, bulky footprint, and more importantly, sacrificed imaging resolution due to non-full-aperture illumination for individual wavelengths. Here we report resolution-improved and diffraction-efficient OTSI using in-fiber diffraction for the first time to our knowledge. The key to overcome the existing challenges is a 45° tilted fiber grating (TFG), which serves as a compact in-fiber diffraction device offering improved diffraction efficiency (up to 97%), inherent compatibility with optical fibers, and improved imaging resolution owning to almost full-aperture illumination for all illumination wavelengths. 50 million frames per second imaging of fast moving object at 46 m/s with improved imaging resolution has been demonstrated. This conceptually new in-fiber diffraction design opens the way towards cost-effective, compact and high-resolution OTSI systems for image-based high-throughput detection and measurement.

Three ancient halo subgiants: precise parallaxes, compositions, ages, and implications for globular clusters , ,

Energy Technology Data Exchange (ETDEWEB)

VandenBerg, Don A. [Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, B.C., V8W 2Y2 (Canada); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Nelan, Edmund P. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Nissen, P. E. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Schaefer, Gail H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Harmer, Dianne, E-mail: vandenbe@uvic.ca, E-mail: heb11@psu.edu, E-mail: nelan@stsci.edu, E-mail: pen@phys.au.dk, E-mail: schaefer@chara-array.org, E-mail: diharmer@noao.edu [National Optical Astronomy Observatories, 950 North Cherry Avenue, Tucson, AZ 85726 (United States)

2014-09-10

The most accurate ages for the oldest stars are those obtained for nearby halo subgiants because they depend almost entirely on just the measured parallaxes and absolute oxygen abundances. In this study, we have used the Fine Guidance Sensors on the Hubble Space Telescope to determine trigonometric parallaxes, with precisions of 2.1% or better, for the Population II subgiants HD 84937, HD 132475, and HD 140283. High quality spectra have been used to derive their surface abundances of O, Fe, Mg, Si, and Ca, which are assumed to be 0.1-0.15 dex less than their initial abundances due to the effects of diffusion. Comparisons of isochrones with the three subgiants on the (log T {sub eff}, M{sub V} ) diagram yielded ages of 12.08 ± 0.14, 12.56 ± 0.46, and 14.27 ± 0.38 Gyr for HD 84937, HD 132475, and HD 140283, in turn, where each error bar includes only the parallax uncertainty. The total uncertainty is estimated to be ∼ ± 0.8 Gyr (larger in the case of the near-turnoff star HD 84937). Although the age of HD 140283 is greater than the age of the universe as inferred from the cosmic microwave background by ∼0.4-0.5 Gyr, this discrepancy is at a level of <1σ. Nevertheless, the first Population II stars apparently formed very soon after the Big Bang. (Stellar models that neglect diffusive processes seem to be ruled out as they would predict that HD 140283 is ∼1.5 Gyr older than the universe.) The field halo subgiants appear to be older than globular clusters of similar metallicities: if distances close to those implied by the RR Lyrae standard candle are assumed, M 92 and M 5 are younger than HD 140283 and HD 132475 by ∼1.5 and ∼1.0 Gyr, respectively.

High-Resolution Reciprocal Space Mapping for Characterizing Deformation Structures

DEFF Research Database (Denmark)

Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, Bo

2014-01-01

With high-angular resolution three-dimensional X-ray diffraction (3DXRD), quantitative information is gained about dislocation structures in individual grains in the bulk of a macroscopic specimen by acquiring reciprocal space maps. In high-resolution 3D reciprocal space maps of tensile......-deformed copper, individual, almost dislocation-free subgrains are identified from high-intensity peaks and distinguished by their unique combination of orientation and elastic strain; dislocation walls manifest themselves as a smooth cloud of lower intensity. The elastic strain shows only minor variations within...... dynamics is followed in situ during varying loading conditions by reciprocal space mapping: during uninterrupted tensile deformation, formation of subgrains is observed concurrently with broadening of Bragg reflections shortly after the onset of plastic deformation. When the traction is terminated, stress...

Conflict Resolution Performance in an Experimental Study of En Route Free Maneuvering Operations

Science.gov (United States)

Doble, Nathan A.; Barhydt, Richard; Hitt, James M., II

2005-01-01

NASA has developed a far-term air traffic management concept, termed Distributed Air/Ground Traffic Management (DAG-TM). One component of DAG-TM, En Route Free Maneuvering, allows properly trained flight crews of equipped autonomous aircraft to assume responsibility for separation from other autonomous aircraft and from Instrument Flight Rules (IFR) aircraft. Ground-based air traffic controllers continue to separate IFR traffic and issue flow management constraints to all aircraft. To examine En Route Free Maneuvering operations, a joint human-in-the-loop experiment was conducted in summer 2004 at the NASA Ames and Langley Research Centers. Test subject pilots used desktop flight simulators to resolve traffic conflicts and adhere to air traffic flow constraints issued by subject controllers. The experimental airspace integrated both autonomous and IFR aircraft at varying traffic densities. This paper presents a subset of the En Route Free Maneuvering experimental results, focusing on airborne and ground-based conflict resolution, and the effects of increased traffic levels on the ability of pilots and air traffic controllers to perform this task. The results show that, in general, increases in autonomous traffic do not significantly impact conflict resolution performance. In addition, pilot acceptability of autonomous operations remains high throughout the range of traffic densities studied. Together with previously reported findings, these results continue to support the feasibility of the En Route Free Maneuvering component of DAG-TM.

Software-Based Adjustment of Mobile Autostereoscopic Graphics Using Static Parallax Barriers

DEFF Research Database (Denmark)

Paprocki, Martin Marko; Krog, Kim Srirat; Kristoffersen, Morten Bak

2012-01-01

We show that the autostereoscopic display of stereoscopic images using a static parallax barrier can be improved by adapting the rendering to the angle under which the user is looking at a mobile display; thus, ghosting artifacts and depth reversals can often be avoided even if the user tilts the...

Label-free cellular structure imaging with 82 nm lateral resolution using an electron-beam excitation-assisted optical microscope.

Science.gov (United States)

Fukuta, Masahiro; Masuda, Yuriko; Inami, Wataru; Kawata, Yoshimasa

2016-07-25

We present label-free and high spatial-resolution imaging for specific cellular structures using an electron-beam excitation-assisted optical microscope (EXA microscope). Images of the actin filament and mitochondria of stained HeLa cells, obtained by fluorescence and EXA microscopy, were compared to identify cellular structures. Based on these results, we demonstrated the feasibility of identifying label-free cellular structures at a spatial resolution of 82 nm. Using numerical analysis, we calculated the imaging depth region and determined the spot size of a cathodoluminescent (CL) light source to be 83 nm at the membrane surface.

High-resolution X-ray television and high-resolution video recorders

International Nuclear Information System (INIS)

Haendle, J.; Horbaschek, H.; Alexandrescu, M.

1977-01-01

The improved transmission properties of the high-resolution X-ray television chain described here make it possible to transmit more information per television image. The resolution in the fluoroscopic image, which is visually determined, depends on the dose rate and the inertia of the television pick-up tube. This connection is discussed. In the last few years, video recorders have been increasingly used in X-ray diagnostics. The video recorder is a further quality-limiting element in X-ray television. The development of function patterns of high-resolution magnetic video recorders shows that this quality drop may be largely overcome. The influence of electrical band width and number of lines on the resolution in the X-ray television image stored is explained in more detail. (orig.) [de

Longitudinal profile diagnostic scheme with subfemtosecond resolution for high-brightness electron beams

Directory of Open Access Journals (Sweden)

G. Andonian

2011-07-01

Full Text Available High-resolution measurement of the longitudinal profile of a relativistic electron beam is of utmost importance for linac based free-electron lasers and other advanced accelerator facilities that employ ultrashort bunches. In this paper, we investigate a novel scheme to measure ultrashort bunches (subpicosecond with exceptional temporal resolution (hundreds of attoseconds and dynamic range. The scheme employs two orthogonally oriented deflecting sections. The first imparts a short-wavelength (fast temporal resolution horizontal angular modulation on the beam, while the second imparts a long-wavelength (slow angular kick in the vertical dimension. Both modulations are observable on a standard downstream screen in the form of a streaked sinusoidal beam structure. We demonstrate, using scaled variables in a quasi-1D approximation, an expression for the temporal resolution of the scheme and apply it to a proof-of-concept experiment at the UCLA Neptune high-brightness injector facility. The scheme is also investigated for application at the SLAC NLCTA facility, where we show that the subfemtosecond resolution is sufficient to resolve the temporal structure of the beam used in the echo-enabled free-electron laser. We employ beam simulations to verify the effect for typical Neptune and NLCTA parameter sets and demonstrate the feasibility of the concept.

Research on key technology of yacht positioning based on binocular parallax

Science.gov (United States)

Wang, Wei; Wei, Ping; Liu, Zengzhi

2016-10-01

Yacht has become a fashionable way for entertainment. However, to obtain the precise location of a yacht docked at a port has become one of the concerns of a yacht manager. To deal with this issue, we adopt a positioning method based on the principle of binocular parallax and background difference in this paper. Binocular parallax uses cameras to get multi-dimensional perspective of the yacht based on geometric principle of imaging. In order to simplify the yacht localization problem, we install LED light indicator as the key point on a yacht. And let it flash at a certain frequency during day time and night time. After getting the distance between the LED and the cameras, locating the yacht is easy. Compared with other traditional positioning methods, this method is simpler and easier to implement. In this paper, we study the yacht positioning method using the LED indicator. Simulation experiment is done for a yacht model in the distance of 3 meters. The experimental result shows that our method is feasible and easy to implement with a small 15% positioning error.

Novel geometrical concept of a high-performance brain PET scanner. Principle, design and performance estimates

International Nuclear Information System (INIS)

Seguinot, J.; Braem, A.; Chesi, E.

2006-01-01

We present the principle, a possible implementation and performance estimates of a novel geometrical concept for a high-resolution positron emission tomograph. The concept, which can be for example implemented in a brain PET device, promises to lead to an essentially parallax-free 3D image reconstruction with excellent spatial resolution and contrast, uniform over the complete field of view. The key components are matrices of long axially oriented scintillator crystals which are read out at both extremities by segmented Hybrid Photon Detectors. We discuss the relevant design considerations for a 3D axial PET camera module, motivate parameter and material choices, and estimate its performance in terms of spatial and energy resolution. We support these estimates by Monte Carlo simulations and in some cases by first experimental results. From the performance of a camera module, we extrapolate to the reconstruction resolution of a 3D axial PET scanner in a semi-analytical way and compare it to an existing state-of-the art brain PET device. We finally describe a dedicated data acquisition system, capable to fully exploit the advantages of the proposed concept

Far-field high resolution effects and manipulating of electromagnetic waves based on transformation optics

Science.gov (United States)

Ji, XueBin; Zang, XiaoFei; Li, Zhou; Shi, Cheng; Chen, Lin; Cai, Bin; Zhu, YiMing

2015-05-01

Based on the transformation optics (TO) and the effective medium theory (EMT), a new illusion media with homogeneous and isotropic materials is proposed to realize the far-field high resolution effects. When two point sources with the separation distance of λ0 / 4 are covered with the illusion media (λ0 is the free-space wavelength), the corresponding far-field pattern is equivalent to the case of two point sources with the separation distance larger than λ0 / 2 in free space, leading to the far-field high resolution effects (in free space, the separation distance of λ0 / 4 is less than half-wavelength, and thus the two point sources cannot be distinguished from each other). Furthermore, such illusion media can be applied to design tunable high-directivity antenna and an angle-dependent floating carpet cloak. Full wave simulations are carried out to verify the performance of our device.

OGLE-2016-BLG-0168 Binary Microlensing Event: Prediction and Confirmation of the Microlens Parallax Effect from Space-based Observations

Energy Technology Data Exchange (ETDEWEB)

Shin, I.-G.; Yee, J. C.; Jung, Y. K. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Udalski, A.; Skowron, J.; Mróz, P.; Soszyński, I.; Poleski, R.; Szymański, M. K.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M. [Warsaw University Observatory, Al. Ujazdowskie 4,00-478 Warszawa (Poland); Novati, S. Calchi [IPAC, Mail Code 100-22, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Han, C. [Department of Physics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Albrow, M. D. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch 8020 (New Zealand); Gould, A. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Chung, S.-J.; Hwang, K.-H.; Ryu, Y.-H. [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-Gu, Daejeon 34055 (Korea, Republic of); Collaboration: OGLE Collaboration; KMTNet Group; Spitzer Team; and others

2017-11-01

The microlens parallax is a crucial observable for conclusively identifying the nature of lens systems in microlensing events containing or composed of faint (even dark) astronomical objects such as planets, neutron stars, brown dwarfs, and black holes. With the commencement of a new era of microlensing in collaboration with space-based observations, the microlens parallax can be routinely measured. In addition, space-based observations can provide opportunities to verify the microlens parallax measured from ground-only observations and to find a unique solution to the lensing light-curve analysis. Furthermore, since most space-based observations cannot cover the full light curves of lensing events, it is also necessary to verify the reliability of the information extracted from fragmentary space-based light curves. We conduct a test based on the microlensing event OGLE-2016-BLG-0168, created by a binary lens system consisting of almost equal mass M-dwarf stars, to demonstrate that it is possible to verify the microlens parallax and to resolve degeneracies using the space-based light curve even though the observations are fragmentary. Since space-based observatories will frequently produce fragmentary light curves due to their short observing windows, the methodology of this test will be useful for next-generation microlensing experiments that combine space-based and ground-based collaboration.

Ultra-high-resolution inelastic X-ray scattering at high-repetition-rate self-seeded X-ray free-electron lasers

Energy Technology Data Exchange (ETDEWEB)

Chubar, Oleg [Brookhaven National Laboratory, Upton, NY 11973 (United States); Geloni, Gianluca [European X-ray Free-Electron Laser, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Kocharyan, Vitali [Deutsches Elektronen-Synchrotron, 22761 Hamburg (Germany); Madsen, Anders [European X-ray Free-Electron Laser, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Saldin, Evgeni; Serkez, Svitozar [Deutsches Elektronen-Synchrotron, 22761 Hamburg (Germany); Shvyd’ko, Yuri, E-mail: shvydko@aps.anl.gov [Argonne National Laboratory, Argonne, IL 60439 (United States); Sutter, John [Diamond Light Source Ltd, Didcot OX11 0DE (United Kingdom)

2016-02-12

This article explores novel opportunities for ultra-high-resolution inelastic X-ray scattering (IXS) at high-repetition-rate self-seeded XFELs. These next-generation light sources are promising a more than three orders of magnitude increase in average spectral flux compared with what is possible with storage-ring-based radiation sources. In combination with the advanced IXS spectrometer described here, this may become a real game-changer for ultra-high-resolution X-ray spectroscopies, and hence for the studies of dynamics in condensed matter systems. Inelastic X-ray scattering (IXS) is an important tool for studies of equilibrium dynamics in condensed matter. A new spectrometer recently proposed for ultra-high-resolution IXS (UHRIX) has achieved 0.6 meV and 0.25 nm{sup −1} spectral and momentum-transfer resolutions, respectively. However, further improvements down to 0.1 meV and 0.02 nm{sup −1} are required to close the gap in energy–momentum space between high- and low-frequency probes. It is shown that this goal can be achieved by further optimizing the X-ray optics and by increasing the spectral flux of the incident X-ray pulses. UHRIX performs best at energies from 5 to 10 keV, where a combination of self-seeding and undulator tapering at the SASE-2 beamline of the European XFEL promises up to a 100-fold increase in average spectral flux compared with nominal SASE pulses at saturation, or three orders of magnitude more than what is possible with storage-ring-based radiation sources. Wave-optics calculations show that about 7 × 10{sup 12} photons s{sup −1} in a 90 µeV bandwidth can be achieved on the sample. This will provide unique new possibilities for dynamics studies by IXS.

Pyrosequencing™ : A one-step method for high resolution HLA typing

Directory of Open Access Journals (Sweden)

Marincola Francesco M

2003-11-01

Full Text Available Abstract While the use of high-resolution molecular typing in routine matching of human leukocyte antigens (HLA is expected to improve unrelated donor selection and transplant outcome, the genetic complexity of HLA still makes the current methodology limited and laborious. Pyrosequencing™ is a gel-free, sequencing-by-synthesis method. In a Pyrosequencing reaction, nucleotide incorporation proceeds sequentially along each DNA template at a given nucleotide dispensation order (NDO that is programmed into a pyrosequencer. Here we describe the design of a NDO that generates a pyrogram unique for any given allele or combination of alleles. We present examples of unique pyrograms generated from each of two heterozygous HLA templates, which would otherwise remain cis/trans ambiguous using standard sequencing based typing (SBT method. In addition, we display representative data that demonstrate long read and linear signal generation. These features are prerequisite of high-resolution typing and automated data analysis. In conclusion Pyrosequencing is a one-step method for high resolution DNA typing.

The roles of visual parallax and edge attraction in the foraging behaviour of the butterfly Papilio xuthus.

Science.gov (United States)

Stewart, Finlay J; Kinoshita, Michiyo; Arikawa, Kentaro

2015-06-01

Several examples of insects using visual motion to measure distance have been documented, from locusts peering to gauge the proximity of prey, to honeybees performing visual odometry en route between the hive and a flower patch. However, whether the use of parallax information is confined to specialised behaviours like these or represents a more general purpose sensory capability, is an open question. We investigate this issue in the foraging swallowtail butterfly Papilio xuthus, which we trained to associate a target presented on a monitor with a food reward. We then tracked the animal's flight in real-time, allowing us to manipulate the size and/or position of the target in a closed-loop manner to create the illusion that it is situated either above or below the monitor surface. Butterflies are less attracted to (i.e. slower to approach) targets that appear, based on motion parallax, to be more distant. Furthermore, we found that the number of abortive descent manoeuvres performed prior to the first successful target approach varies according to the depth of the virtual target, with expansion and parallax cues having effects of opposing polarity. However, we found no evidence that Papilio modulate the kinematic parameters of their descents according to the apparent distance of the target. Thus, we argue that motion parallax is used to identify a proximal target object, but that the subsequent process of approaching it is based on stabilising its edge in the 2D space of the retina, without estimating its distance. © 2015. Published by The Company of Biologists Ltd.

No-Reference Stereoscopic IQA Approach: From Nonlinear Effect to Parallax Compensation

Directory of Open Access Journals (Sweden)

Ke Gu

2012-01-01

Full Text Available The last decade has seen a booming of the applications of stereoscopic images/videos and the corresponding technologies, such as 3D modeling, reconstruction, and disparity estimation. However, only a very limited number of stereoscopic image quality assessment metrics was proposed through the years. In this paper, we propose a new no-reference stereoscopic image quality assessment algorithm based on the nonlinear additive model, ocular dominance model, and saliency based parallax compensation. Our studies using the Toyama database result in three valuable findings. First, quality of the stereoscopic image has a nonlinear relationship with a direct summation of two monoscopic image qualities. Second, it is a rational assumption that the right-eye response has the higher impact on the stereoscopic image quality, which is based on a sampling survey in the ocular dominance research. Third, the saliency based parallax compensation, resulted from different stereoscopic image contents, is considerably valid to improve the prediction performance of image quality metrics. Experimental results confirm that our proposed stereoscopic image quality assessment paradigm has superior prediction accuracy as compared to state-of-the-art competitors.

The solar neighborhood. XXXIII. Parallax results from the CTIOPI 0.9 m program: trigonometric parallaxes of Nearby low-mass active and young systems

International Nuclear Information System (INIS)

Riedel, Adric R.; Cruz, Kelle L.; Finch, Charlie T.; Henry, Todd J.; Jao, Wei-Chun; White, Russel J.; Gies, Douglas R.; Dieterich, Sergio B.; Winters, Jennifer G.; Davison, Cassy L.; Subasavage, John P.; Malo, Lison; Rodriguez, David R.; Nelan, Edmund P.; Blunt, Sarah C.; Rice, Emily L.; Ianna, Philip A.

2014-01-01

We present basic observational data and association membership analysis for 45 young and active low-mass stellar systems from the ongoing Research Consortium On Nearby Stars photometry and astrometry program at the Cerro Tololo Inter-American Observatory. Most of these systems have saturated X-ray emission (log (L X /L bol ) > –3.5) based on X-ray fluxes from the ROSAT All-Sky Survey, and many are significantly more luminous than main-sequence stars of comparable color. We present parallaxes and proper motions, Johnson-Kron-Cousins VRI photometry, and multiplicity observations from the CTIOPI program on the CTIO 0.9 m telescope. To this we add low-resolution optical spectroscopy and line measurements from the CTIO 1.5 m telescope, and interferometric binary measurements from the Hubble Space Telescope Fine Guidance Sensors. We also incorporate data from published sources: JHK S photometry from the Two Micron All Sky Survey point source catalog, X-ray data from the ROSAT All-Sky Survey, and radial velocities from literature sources. Within the sample of 45 systems, we identify 21 candidate low-mass pre-main-sequence members of nearby associations, including members of β Pictoris, TW Hydrae, Argus, AB Doradus, two ambiguous ≈30 Myr old systems, and one object that may be a member of the Ursa Major moving group. Of the 21 candidate young systems, 14 are newly identified as a result of this work, and six of those are within 25 pc of the Sun.

Identification/quantification of free and bound phenolic acids in peel and pulp of apples (Malus domestica) using high resolution mass spectrometry (HRMS).

Science.gov (United States)

Lee, Jihyun; Chan, Bronte Lee Shan; Mitchell, Alyson E

2017-01-15

Free and bound phenolic acids were measured in the pulp and peel of four varieties of apples using high resolution mass spectrometry. Twenty-five phenolic acids were identified and included: 8 hydroxybenzoic acids, 11 hydroxycinnamic acids, 5 hydroxyphenylacetic acids, and 1 hydoxyphenylpropanoic acid. Several phenolics are tentatively identified for the first time in apples and include: methyl gallate, ethyl gallate, hydroxy phenyl acetic acid, three phenylacetic acid isomers, 3-(4-hydroxyphenyl)propionic acid, and homoveratric acid. With exception of chlorogenic and caffeic acid, most phenolic acids were quantified for the first time in apples. Significant varietal differences (pacids were higher in the pulp as compared to apple peel (dry weight) in all varieties. Coumaroylquinic, protocatechuic, 4-hydroxybenzoic, vanillic and t-ferulic acids were present in free forms. With exception of chlorogenic acid, all other phenolic acids were present only as bound forms. Copyright © 2016 Elsevier Ltd. All rights reserved.

ANL high resolution injector

International Nuclear Information System (INIS)

Minehara, E.; Kutschera, W.; Hartog, P.D.; Billquist, P.

1985-01-01

The ANL (Argonne National Laboratory) high-resolution injector has been installed to obtain higher mass resolution and higher preacceleration, and to utilize effectively the full mass range of ATLAS (Argonne Tandem Linac Accelerator System). Preliminary results of the first beam test are reported briefly. The design and performance, in particular a high-mass-resolution magnet with aberration compensation, are discussed. 7 refs., 5 figs., 2 tabs

On temporal correlations in high-resolution frequency counting

OpenAIRE

Dunker, Tim; Hauglin, Harald; Rønningen, Ole Petter

2016-01-01

We analyze noise properties of time series of frequency data from different counting modes of a Keysight 53230A frequency counter. We use a 10 MHz reference signal from a passive hydrogen maser connected via phase-stable Huber+Suhner Sucoflex 104 cables to the reference and input connectors of the counter. We find that the high resolution gap-free (CONT) frequency counting process imposes long-term correlations in the output data, resulting in a modified Allan deviation that is characteristic...

PARALLAXES AND PROPER MOTIONS OF ULTRACOOL BROWN DWARFS OF SPECTRAL TYPES Y AND LATE T

International Nuclear Information System (INIS)

Marsh, Kenneth A.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Wright, Edward L.; Cushing, Michael C.; Skrutskie, Michael F.; Eisenhardt, Peter R.

2013-01-01

We present astrometric measurements of 11 nearby ultracool brown dwarfs of spectral types Y and late-T, based on imaging observations from a variety of space-based and ground-based telescopes. These measurements have been used to estimate relative parallaxes and proper motions via maximum likelihood fitting of geometric model curves. To compensate for the modest statistical significance (∼ tan , assumed similar to that implied by previous observations of T dwarfs. Our estimated distances are therefore somewhat dependent on that assumption. Nevertheless, the results have yielded distances for five of our eight Y dwarfs and all three T dwarfs. Estimated distances in all cases are ∼> 3 pc. In addition, we have obtained significant estimates of V tan for two of the Y dwarfs; both are –1 , consistent with membership in the thin disk population. Comparison of absolute magnitudes with model predictions as a function of color shows that the Y dwarfs are significantly redder in J – H than predicted by a cloud-free model.

Solving phase appearance/disappearance two-phase flow problems with high resolution staggered grid and fully implicit schemes by the Jacobian-free Newton–Krylov Method

Energy Technology Data Exchange (ETDEWEB)

Zou, Ling; Zhao, Haihua; Zhang, Hongbin

2016-04-01

The phase appearance/disappearance issue presents serious numerical challenges in two-phase flow simulations. Many existing reactor safety analysis codes use different kinds of treatments for the phase appearance/disappearance problem. However, to our best knowledge, there are no fully satisfactory solutions. Additionally, the majority of the existing reactor system analysis codes were developed using low-order numerical schemes in both space and time. In many situations, it is desirable to use high-resolution spatial discretization and fully implicit time integration schemes to reduce numerical errors. In this work, we adapted a high-resolution spatial discretization scheme on staggered grid mesh and fully implicit time integration methods (such as BDF1 and BDF2) to solve the two-phase flow problems. The discretized nonlinear system was solved by the Jacobian-free Newton Krylov (JFNK) method, which does not require the derivation and implementation of analytical Jacobian matrix. These methods were tested with a few two-phase flow problems with phase appearance/disappearance phenomena considered, such as a linear advection problem, an oscillating manometer problem, and a sedimentation problem. The JFNK method demonstrated extremely robust and stable behaviors in solving the two-phase flow problems with phase appearance/disappearance. No special treatments such as water level tracking or void fraction limiting were used. High-resolution spatial discretization and second- order fully implicit method also demonstrated their capabilities in significantly reducing numerical errors.

The importance of vertical resolution in the free troposphere for modeling intercontinental plumes

Science.gov (United States)

Zhuang, Jiawei; Jacob, Daniel J.; Eastham, Sebastian D.

2018-05-01

Chemical plumes in the free troposphere can preserve their identity for more than a week as they are transported on intercontinental scales. Current global models cannot reproduce this transport. The plumes dilute far too rapidly due to numerical diffusion in sheared flow. We show how model accuracy can be limited by either horizontal resolution (Δx) or vertical resolution (Δz). Balancing horizontal and vertical numerical diffusion, and weighing computational cost, implies an optimal grid resolution ratio (Δx / Δz)opt ˜ 1000 for simulating the plumes. This is considerably higher than current global models (Δx / Δz ˜ 20) and explains the rapid plume dilution in the models as caused by insufficient vertical resolution. Plume simulations with the Geophysical Fluid Dynamics Laboratory Finite-Volume Cubed-Sphere Dynamical Core (GFDL-FV3) over a range of horizontal and vertical grid resolutions confirm this limiting behavior. Our highest-resolution simulation (Δx ≈ 25 km, Δz ≈ 80 m) preserves the maximum mixing ratio in the plume to within 35 % after 8 days in strongly sheared flow, a drastic improvement over current models. Adding free tropospheric vertical levels in global models is computationally inexpensive and would also improve the simulation of water vapor.

Effects of the Environment Temperature on the Characteristic of Parallax Ping Ultrasonic Sensor

Directory of Open Access Journals (Sweden)

Tony Stănescu

2014-12-01

Full Text Available This paper presents some characteristics of the Parallax PING ultrasonic sensor and the way the environmental temperature affects them. The used sensor functions at 40 KHz. There is also presented the experimental test setup and the authors’ conclusions on the functioning of the sensor at various temperatures.

ASTROMETRY WITH THE HUBBLE SPACE TELESCOPE: TRIGONOMETRIC PARALLAXES OF PLANETARY NEBULA NUCLEI NGC 6853, NGC 7293, ABELL 31, AND DeHt 5

International Nuclear Information System (INIS)

Benedict, G. Fritz; McArthur, Barbara E.; Napiwotzki, Ralf; Harrison, Thomas E.; Harris, Hugh C.; Nelan, Edmund; Bond, Howard E.; Patterson, Richard J.; Ciardullo, Robin

2009-01-01

We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1r and FGS 3, white-light interferometers on the Hubble Space Telescope. Proper motions, spectral classifications and VJHKT 2 M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, σ π /π = 5%. Derived distances are: d NGC6853 = 405 +28 -25 pc, d NGC7293 = 216 +14 -12 pc, d Abell31 = 621 +91 -70 pc, and d DeHt5 = 345 +19 -17 pc. These PNNi distances are all smaller than previously derived from spectroscopic analyses of the central stars. To obtain absolute magnitudes from these distances requires estimates of interstellar extinction. We average extinction measurements culled from the literature, from reddening based on PNNi intrinsic colors derived from model SEDs, and an assumption that each PNN experiences the same rate of extinction as a function of distance as do the reference stars nearest (in angular separation) to each central star. We also apply Lutz-Kelker bias corrections. The absolute magnitudes and effective temperatures permit estimates of PNNi radii through both the Stefan-Boltzmann relation and Eddington fluxes. Comparing absolute magnitudes with post-AGB models provides mass estimates. Masses cluster around 0.57 M odot , close to the peak of the white dwarf mass distribution. Adding a few more PNNi with well-determined distances and masses, we compare all the PNNi with cooler white

Ultrahigh-resolution imaging of the human brain with phase-cycled balanced steady-state free precession at 7 T.

Science.gov (United States)

Zeineh, Michael M; Parekh, Mansi B; Zaharchuk, Greg; Su, Jason H; Rosenberg, Jarrett; Fischbein, Nancy J; Rutt, Brian K

2014-05-01

The objectives of this study were to acquire ultra-high resolution images of the brain using balanced steady-state free precession (bSSFP) at 7 T and to identify the potential utility of this sequence. Eight volunteers participated in this study after providing informed consent. Each volunteer was scanned with 8 phase cycles of bSSFP at 0.4-mm isotropic resolution using 0.5 number of excitations and 2-dimensional parallel acceleration of 1.75 × 1.75. Each phase cycle required 5 minutes of scanning, with pauses between the phase cycles allowing short periods of rest. The individual phase cycles were aligned and then averaged. The same volunteers underwent scanning using 3-dimensional (3D) multiecho gradient recalled echo at 0.8-mm isotropic resolution, 3D Cube T2 at 0.7-mm isotropic resolution, and thin-section coronal oblique T2-weighted fast spin echo at 0.22 × 0.22 × 2.0-mm resolution for comparison. Two neuroradiologists assessed image quality and potential research and clinical utility. The volunteers generally tolerated the scan sessions well, and composite high-resolution bSSFP images were produced for each volunteer. Rater analysis demonstrated that bSSFP had a superior 3D visualization of the microarchitecture of the hippocampus, very good contrast to delineate the borders of the subthalamic nucleus, and relatively good B1 homogeneity throughout. In addition to an excellent visualization of the cerebellum, subtle details of the brain and skull base anatomy were also easier to identify on the bSSFP images, including the line of Gennari, membrane of Liliequist, and cranial nerves. Balanced steady-state free precession had a strong iron contrast similar to or better than the comparison sequences. However, cortical gray-white contrast was significantly better with Cube T2 and T2-weighted fast spin echo. Balanced steady-state free precession can facilitate ultrahigh-resolution imaging of the brain. Although total imaging times are long, the individually short

The solar neighborhood. XXXIII. Parallax results from the CTIOPI 0.9 m program: trigonometric parallaxes of Nearby low-mass active and young systems

Energy Technology Data Exchange (ETDEWEB)

Riedel, Adric R.; Cruz, Kelle L. [Department of Physics and Astronomy, Hunter College, The City University of New York, 695 Park Avenue, New York, NY 10065 (United States); Finch, Charlie T. [Astrometry Department, U.S. Naval Observatory, Washington, DC 20392 (United States); Henry, Todd J.; Jao, Wei-Chun; White, Russel J.; Gies, Douglas R.; Dieterich, Sergio B.; Winters, Jennifer G.; Davison, Cassy L. [Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States); Subasavage, John P. [United States Naval Observatory, Flagstaff, AZ 86001 (United States); Malo, Lison [Département de Physique et Observatoire du Mont-Megantic, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, QC H3C 3J7 (Canada); Rodriguez, David R. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Las Condes, Santiago (Chile); Nelan, Edmund P. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Blunt, Sarah C.; Rice, Emily L. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Ianna, Philip A., E-mail: ar494@hunter.cuny.edu [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)

2014-04-01

We present basic observational data and association membership analysis for 45 young and active low-mass stellar systems from the ongoing Research Consortium On Nearby Stars photometry and astrometry program at the Cerro Tololo Inter-American Observatory. Most of these systems have saturated X-ray emission (log (L{sub X} /L {sub bol}) > –3.5) based on X-ray fluxes from the ROSAT All-Sky Survey, and many are significantly more luminous than main-sequence stars of comparable color. We present parallaxes and proper motions, Johnson-Kron-Cousins VRI photometry, and multiplicity observations from the CTIOPI program on the CTIO 0.9 m telescope. To this we add low-resolution optical spectroscopy and line measurements from the CTIO 1.5 m telescope, and interferometric binary measurements from the Hubble Space Telescope Fine Guidance Sensors. We also incorporate data from published sources: JHK{sub S} photometry from the Two Micron All Sky Survey point source catalog, X-ray data from the ROSAT All-Sky Survey, and radial velocities from literature sources. Within the sample of 45 systems, we identify 21 candidate low-mass pre-main-sequence members of nearby associations, including members of β Pictoris, TW Hydrae, Argus, AB Doradus, two ambiguous ≈30 Myr old systems, and one object that may be a member of the Ursa Major moving group. Of the 21 candidate young systems, 14 are newly identified as a result of this work, and six of those are within 25 pc of the Sun.

Sparsity-Based Pixel Super Resolution for Lens-Free Digital In-line Holography.

Science.gov (United States)

Song, Jun; Leon Swisher, Christine; Im, Hyungsoon; Jeong, Sangmoo; Pathania, Divya; Iwamoto, Yoshiko; Pivovarov, Misha; Weissleder, Ralph; Lee, Hakho

2016-04-21

Lens-free digital in-line holography (LDIH) is a promising technology for portable, wide field-of-view imaging. Its resolution, however, is limited by the inherent pixel size of an imaging device. Here we present a new computational approach to achieve sub-pixel resolution for LDIH. The developed method is a sparsity-based reconstruction with the capability to handle the non-linear nature of LDIH. We systematically characterized the algorithm through simulation and LDIH imaging studies. The method achieved the spatial resolution down to one-third of the pixel size, while requiring only single-frame imaging without any hardware modifications. This new approach can be used as a general framework to enhance the resolution in nonlinear holographic systems.

The importance of vertical resolution in the free troposphere for modeling intercontinental plumes

Directory of Open Access Journals (Sweden)

J. Zhuang

2018-05-01

Full Text Available Chemical plumes in the free troposphere can preserve their identity for more than a week as they are transported on intercontinental scales. Current global models cannot reproduce this transport. The plumes dilute far too rapidly due to numerical diffusion in sheared flow. We show how model accuracy can be limited by either horizontal resolution (Δx or vertical resolution (Δz. Balancing horizontal and vertical numerical diffusion, and weighing computational cost, implies an optimal grid resolution ratio (Δx ∕ Δzopt ∼ 1000 for simulating the plumes. This is considerably higher than current global models (Δx ∕ Δz ∼ 20 and explains the rapid plume dilution in the models as caused by insufficient vertical resolution. Plume simulations with the Geophysical Fluid Dynamics Laboratory Finite-Volume Cubed-Sphere Dynamical Core (GFDL-FV3 over a range of horizontal and vertical grid resolutions confirm this limiting behavior. Our highest-resolution simulation (Δx ≈ 25 km, Δz  ≈  80 m preserves the maximum mixing ratio in the plume to within 35 % after 8 days in strongly sheared flow, a drastic improvement over current models. Adding free tropospheric vertical levels in global models is computationally inexpensive and would also improve the simulation of water vapor.

Developmental approach towards high resolution optical coherence tomography for glaucoma diagnostics

Science.gov (United States)

Kemper, Björn; Ketelhut, Steffi; Heiduschka, Peter; Thorn, Marie; Larsen, Michael; Schnekenburger, Jürgen

2018-02-01

Glaucoma is caused by a pathological rise in the intraocular pressure, which results in a progressive loss of vision by a damage to retinal cells and the optical nerve head. Early detection of pressure-induced damage is thus essential for the reduction of eye pressure and to prevent severe incapacity or blindness. Within the new European Project GALAHAD (Glaucoma Advanced, Label free High Resolution Automated OCT Diagnostics), we will develop a new low-cost and high-resolution OCT system for the early detection of glaucoma. The device is designed to improve diagnosis based on a new system of optical coherence tomography. Although OCT systems are at present available in ophthalmology centres, high-resolution devices are extremely expensive. The novelty of the new Galahad system is its super wideband light source to achieve high image resolution at a reasonable cost. Proof of concept experiments with cell and tissue Glaucoma test standards and animal models are planned for the test of the new optical components and new algorithms performance for the identification of Glaucoma associated cell and tissue structures. The intense training of the software systems with various samples should result in a increased sensitivity and specificity of the OCT software system.

Rapid profiling of antimicrobial compounds characterising B. subtilis TR50 cell-free filtrate by high-performance liquid chromatography coupled to high-resolution Orbitrap™ mass spectrometry.

Science.gov (United States)

Monaci, Linda; Quintieri, Laura; Caputo, Leonardo; Visconti, Angelo; Baruzzi, Federico

2016-01-15

Several Bacillus strains, typically isolated from different food sources, represent renowned producers of a multitude of low and high molecular weight compounds, including lipopeptides and macrolactones, with an importance for their antimicrobial activity. The high homology shared by many of these compounds also occurring as closely related isoforms poses a challenge in their prompt detection. Identification and structural elucidation is generally achieved by matrix-assisted laser desorption/ionization (MALDI) or liquid chromatography (LC) coupled to mass spectrometry (MS) after a pre-fractionation and/or purification step of the extract. In this paper we report the application of a method based on LC separation and high-resolution Orbitrap™-based MS for the rapid screening of raw filtrate of the strain Bacillus subtilis TR50 endowed with antimicrobial activity, without requiring any sample pre-treatment. Upon direct analysis of the cell-free filtrate of Bacillus subtilis TR50 by high-resolution mass spectrometry (HRMS), different compounds families, that proved to exert a remarked antimicrobial activity against several foodborne pathogens, can be readily displayed along the chromatographic run. Among them, three different classes were identified and characterized belonging to the iturin, fengycin and surfactin groups. The high resolving power and accurate mass accuracy provided by the HRMS system in use ensured an enhanced selectivity compared to other mass spectrometers. In addition, after activation of the HCD cell, the HR-MS/MS spectra can provide insights in the structural elucidation of several compounds. The acquisition of HRMS spectra of raw filtrates of subtilis strains allows untargeted analysis of the major classes of compounds produced to be performed, thus facilitating identification of other unknown bioactive molecules after retrospective analysis. These features make this approach a fast tool applicable to the rapid screening and further

High-resolution in-source laser spectroscopy in perpendicular geometry

Energy Technology Data Exchange (ETDEWEB)

Heinke, R., E-mail: reinhard.heinke@uni-mainz.de; Kron, T. [Universität Mainz, Institut für Physik (Germany); Raeder, S. [Helmholtz-Institut Mainz (Germany); Reich, T.; Schönberg, P. [Universität Mainz, Institut für Kernchemie (Germany); Trümper, M.; Weichhold, C.; Wendt, K. [Universität Mainz, Institut für Physik (Germany)

2017-11-15

Operation of the novel laser ion source unit LIST (Laser Ion Source and Trap), operating at the on-line radioactive ion beam facility ISOLDE at CERN allowed for the production of ultra-pure beams of exotic isotopes far-off stability as well as direct isobar-free laser spectroscopy, giving access to the study of atomic and nuclear properties of so far inaccessible nuclides. We present a specific upgrade and adaption of the LIST targeted for high resolution spectroscopy with a Doppler-reduced perpendicular atom - laser beam geometry. With this PI-LIST (Perpendicularly Illuminated Laser Ion Source and Trap) setup, experimental linewidths below 100 MHz could be demonstrated in optical laser spectroscopy off-line, applying a pulsed injection-locked high repetition rate Ti:sapphire laser. A dual repeller configuration ensured highest suppression of isobaric interferences and almost background-free measurements on small samples in the order of 10{sup 11} atoms.

Quasar Parallax: a Method for Determining Direct Geometrical Distances to Quasars

OpenAIRE

Elvis, Martin; Karovska, Margarita

2002-01-01

We describe a novel method to determine direct geometrical distances to quasars that can measure the cosmological constant, Lambda, with minimal assumptions. This method is equivalent to geometric parallax, with the `standard length' being the size of the quasar broad emission line region (BELR) as determined from the light travel time measurements of reverberation mapping. The effect of non-zero Lambda on angular diameter is large, 40% at z=2, so mapping angular diameter distances vs. redshi...

Automated Segmentation of High-Resolution Photospheric Images of Active Regions

Science.gov (United States)

Yang, Meng; Tian, Yu; Rao, Changhui

2018-02-01

Due to the development of ground-based, large-aperture solar telescopes with adaptive optics (AO) resulting in increasing resolving ability, more accurate sunspot identifications and characterizations are required. In this article, we have developed a set of automated segmentation methods for high-resolution solar photospheric images. Firstly, a local-intensity-clustering level-set method is applied to roughly separate solar granulation and sunspots. Then reinitialization-free level-set evolution is adopted to adjust the boundaries of the photospheric patch; an adaptive intensity threshold is used to discriminate between umbra and penumbra; light bridges are selected according to their regional properties from candidates produced by morphological operations. The proposed method is applied to the solar high-resolution TiO 705.7-nm images taken by the 151-element AO system and Ground-Layer Adaptive Optics prototype system at the 1-m New Vacuum Solar Telescope of the Yunnan Observatory. Experimental results show that the method achieves satisfactory robustness and efficiency with low computational cost on high-resolution images. The method could also be applied to full-disk images, and the calculated sunspot areas correlate well with the data given by the National Oceanic and Atmospheric Administration (NOAA).

Simple 3-D stimulus for motion parallax and its simulation.

Science.gov (United States)

Ono, Hiroshi; Chornenkyy, Yevgen; D'Amour, Sarah

2013-01-01

Simulation of a given stimulus situation should produce the same perception as the original. Rogers et al (2009 Perception 38 907-911) simulated Wheeler's (1982, PhD thesis, Rutgers University, NJ) motion parallax stimulus and obtained quite different perceptions. Wheeler's observers were unable to reliably report the correct direction of depth, whereas Rogers's were. With three experiments we explored the possible reasons for the discrepancy. Our results suggest that Rogers was able to see depth from the simulation partly due to his experience seeing depth with random dot surfaces.

Design considerations for a high-spatial-resolution positron camera with dense-drift-space MWPC's

International Nuclear Information System (INIS)

Del Guerra, A.; Perez-Mendez, V.; Schwartz, G.; Nelson, W.R.

1982-10-01

A multiplane Positron Cameris is proposed, made of six MWPC modules arranged to form the lateral surface of a hexagonal prism. Each module (50 x 50 cm 2 ) has a 2 cm thick lead-glass tube converter on both sides of a MWPC pressurized to 2 atm. Experimental measurements are presented to show how to reduce the parallax error by determining in which of the two converter layers the photon has interacted. The results of a detailed Monte Carlo calculation for the efficiency of this type of converter are shown to be in excellent agreement with the experimental measurements. The expected performance of the Positron Camera is presented: a true coincidence rate of 56,000 counts/s (with an equal accidental coincidence rate and a 30% Compton scatter contamination) and a spatial resolution better than 5.0 mm (FWHM) for a 400 μ Ci point-like source embedded in a 10 cm radius water phantom

The Solar Neighborhood. XLII. Parallax Results from the CTIOPI 0.9 m Program—Identifying New Nearby Subdwarfs Using Tangential Velocities and Locations on the H–R Diagram

Science.gov (United States)

Jao, Wei-Chun; Henry, Todd J.; Winters, Jennifer G.; Subasavage, John P.; Riedel, Adric R.; Silverstein, Michele L.; Ianna, Philip A.

2017-11-01

Parallaxes, proper motions, and optical photometry are presented for 51 systems consisting of 37 cool subdwarf and 14 additional high proper motion systems. Thirty-seven systems have parallaxes reported for the first time, 15 of which have proper motions of at least 1″ yr‑1. The sample includes 22 newly identified cool subdwarfs within 100 pc, of which three are within 25 pc, and an additional five subdwarfs from 100 to 160 pc. Two systems—LSR 1610-0040 AB and LHS 440 AB—are close binaries exhibiting clear astrometric perturbations that will ultimately provide important masses for cool subdwarfs. We use the accurate parallaxes and proper motions provided here, combined with additional data from our program and others, to determine that effectively all nearby stars with tangential velocities greater than 200 km s‑1 are subdwarfs. We compare a sample of 167 confirmed cool subdwarfs to nearby main sequence dwarfs and Pleiades members on an observational Hertzsprung–Russell diagram using M V versus (V ‑ K s ) to map trends of age and metallicity. We find that subdwarfs are clearly separated for spectral types K5–M5, indicating that the low metallicities of subdwarfs set them apart in the H–R diagram for (V ‑ K s ) = 3–6. We then apply the tangential velocity cutoff and the subdwarf region of the H–R diagram to stars with parallaxes from Gaia Data Release 1 and the MEarth Project to identify a total of 29 new nearby subdwarf candidates that fall clearly below the main sequence.

Ultra-high resolution protein crystallography

International Nuclear Information System (INIS)

Takeda, Kazuki; Hirano, Yu; Miki, Kunio

2010-01-01

Many protein structures have been determined by X-ray crystallography and deposited with the Protein Data Bank. However, these structures at usual resolution (1.5< d<3.0 A) are insufficient in their precision and quantity for elucidating the molecular mechanism of protein functions directly from structural information. Several studies at ultra-high resolution (d<0.8 A) have been performed with synchrotron radiation in the last decade. The highest resolution of the protein crystals was achieved at 0.54 A resolution for a small protein, crambin. In such high resolution crystals, almost all of hydrogen atoms of proteins and some hydrogen atoms of bound water molecules are experimentally observed. In addition, outer-shell electrons of proteins can be analyzed by the multipole refinement procedure. However, the influence of X-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. In this review, we summarize refinement procedures, current status and perspectives for ultra high resolution protein crystallography. (author)

Astrometry with Hubble Space Telescope Fine Guidance Sensor 3: The Parallax of the Cataclysmic Variable RW Triangulum

Science.gov (United States)

McArthur, B. E.; Benedict, G. F.; Lee, J.; Lu, C.-L.; van Altena, W. F.; Deliyannis, C. P.; Girard, T.; Fredrick, L. W.; Nelan, E.; Duncombe, R. L.; Hemenway, P. D.; Jefferys, W. H.; Shelus, P. J.; Franz, O. G.; Wasserman, L. H.

1999-07-01

RW Triangulum (RW Tri) is a 13th magnitude nova-like cataclysmic variable star with an orbital period of 0.2319 days (5.56 hr). Infrared observations of RW Tri indicate that its secondary is most likely a late-K dwarf (Dhillon). Past analyses predicted a distance of 270 pc, derived from a blackbody fit to the spectrum of the central part of the disk (Rutten, van Paradijs, & Tinbergen). Recently completed Hubble Space Telescope Fine Guidance Sensor interferometric observations allow us to determine the first trigonometric parallax to RW Tri. This determination puts the distance of RW Tri at 341-31+38, one of the most distant objects with a direct parallax measurement. We compare our result with methods previously employed to estimate distances to cataclysmic variables.

On the optical stability of high-resolution transmission electron microscopes

International Nuclear Information System (INIS)

Barthel, J.; Thust, A.

2013-01-01

In the recent two decades the technique of high-resolution transmission electron microscopy experienced an unprecedented progress through the introduction of hardware aberration correctors and by the improvement of the achievable resolution to the sub-Ångström level. The important aspect that aberration correction at a given resolution requires also a well defined amount of optical stability has received little attention so far. Therefore we investigate the qualification of a variety of high-resolution electron microscopes to maintain an aberration corrected optical state in terms of an optical lifetime. We develop a comprehensive statistical framework for the estimation of the optical lifetime and find remarkably low values between tens of seconds and a couple of minutes. Probability curves are introduced, which inform the operator about the chance to work still in the fully aberration corrected state. - Highlights: • We investigate the temporal stability of optical aberrations in HRTEM. • We develop a statistical framework for the estimation of optical lifetimes. • We introduce plots showing the success probability for aberration-free work. • Optical lifetimes in sub-Ångström electron microscopy are surprisingly low. • The success of aberration correction depends strongly on the optical stability

Super-resolution biomolecular crystallography with low-resolution data.

Science.gov (United States)

Schröder, Gunnar F; Levitt, Michael; Brunger, Axel T

2010-04-22

X-ray diffraction plays a pivotal role in the understanding of biological systems by revealing atomic structures of proteins, nucleic acids and their complexes, with much recent interest in very large assemblies like the ribosome. As crystals of such large assemblies often diffract weakly (resolution worse than 4 A), we need methods that work at such low resolution. In macromolecular assemblies, some of the components may be known at high resolution, whereas others are unknown: current refinement methods fail as they require a high-resolution starting structure for the entire complex. Determining the structure of such complexes, which are often of key biological importance, should be possible in principle as the number of independent diffraction intensities at a resolution better than 5 A generally exceeds the number of degrees of freedom. Here we introduce a method that adds specific information from known homologous structures but allows global and local deformations of these homology models. Our approach uses the observation that local protein structure tends to be conserved as sequence and function evolve. Cross-validation with R(free) (the free R-factor) determines the optimum deformation and influence of the homology model. For test cases at 3.5-5 A resolution with known structures at high resolution, our method gives significant improvements over conventional refinement in the model as monitored by coordinate accuracy, the definition of secondary structure and the quality of electron density maps. For re-refinements of a representative set of 19 low-resolution crystal structures from the Protein Data Bank, we find similar improvements. Thus, a structure derived from low-resolution diffraction data can have quality similar to a high-resolution structure. Our method is applicable to the study of weakly diffracting crystals using X-ray micro-diffraction as well as data from new X-ray light sources. Use of homology information is not restricted to X

High resolution solar observations

International Nuclear Information System (INIS)

Title, A.

1985-01-01

Currently there is a world-wide effort to develop optical technology required for large diffraction limited telescopes that must operate with high optical fluxes. These developments can be used to significantly improve high resolution solar telescopes both on the ground and in space. When looking at the problem of high resolution observations it is essential to keep in mind that a diffraction limited telescope is an interferometer. Even a 30 cm aperture telescope, which is small for high resolution observations, is a big interferometer. Meter class and above diffraction limited telescopes can be expected to be very unforgiving of inattention to details. Unfortunately, even when an earth based telescope has perfect optics there are still problems with the quality of its optical path. The optical path includes not only the interior of the telescope, but also the immediate interface between the telescope and the atmosphere, and finally the atmosphere itself

High speed, High resolution terahertz spectrometers

International Nuclear Information System (INIS)

Kim, Youngchan; Yee, Dae Su; Yi, Miwoo; Ahn, Jaewook

2008-01-01

A variety of sources and methods have been developed for terahertz spectroscopy during almost two decades. Terahertz time domain spectroscopy (THz TDS)has attracted particular attention as a basic measurement method in the fields of THz science and technology. Recently, asynchronous optical sampling (AOS)THz TDS has been demonstrated, featuring rapid data acquisition and a high spectral resolution. Also, terahertz frequency comb spectroscopy (TFCS)possesses attractive features for high precision terahertz spectroscopy. In this presentation, we report on these two types of terahertz spectrometer. Our high speed, high resolution terahertz spectrometer is demonstrated using two mode locked femtosecond lasers with slightly different repetition frequencies without a mechanical delay stage. The repetition frequencies of the two femtosecond lasers are stabilized by use of two phase locked loops sharing the same reference oscillator. The time resolution of our terahertz spectrometer is measured using the cross correlation method to be 270 fs. AOS THz TDS is presented in Fig. 1, which shows a time domain waveform rapidly acquired on a 10ns time window. The inset shows a zoom into the signal with 100ps time window. The spectrum obtained by the fast Fourier Transformation (FFT)of the time domain waveform has a frequency resolution of 100MHz. The dependence of the signal to noise ratio (SNR)on the measurement time is also investigated

DOI resolution measurement and error analysis with LYSO and APDs

International Nuclear Information System (INIS)

Lee, Chae-hun; Cho, Gyuseong

2008-01-01

Spatial resolution degradation in PET occurs at the edge of Field Of View (FOV) due to parallax error. To improve spatial resolution at the edge of FOV, Depth-Of-Interaction (DOI) PET has been investigated and several methods for DOI positioning were proposed. In this paper, a DOI-PET detector module using two 8x4 array avalanche photodiodes (APDs) (Hamamatsu, S8550) and a 2 cm long LYSO scintillation crystal was proposed and its DOI characteristics were investigated experimentally. In order to measure DOI positions, signals from two APDs were compared. Energy resolution was obtained from the sum of two APDs' signals and DOI positioning error was calculated. Finally, an optimum DOI step size in a 2 cm long LYSO were suggested to help to design a DOI-PET

Length-extension resonator as a force sensor for high-resolution frequency-modulation atomic force microscopy in air.

Science.gov (United States)

Beyer, Hannes; Wagner, Tino; Stemmer, Andreas

2016-01-01

Frequency-modulation atomic force microscopy has turned into a well-established method to obtain atomic resolution on flat surfaces, but is often limited to ultra-high vacuum conditions and cryogenic temperatures. Measurements under ambient conditions are influenced by variations of the dew point and thin water layers present on practically every surface, complicating stable imaging with high resolution. We demonstrate high-resolution imaging in air using a length-extension resonator operating at small amplitudes. An additional slow feedback compensates for changes in the free resonance frequency, allowing stable imaging over a long period of time with changing environmental conditions.

Limiting liability via high resolution image processing

Energy Technology Data Exchange (ETDEWEB)

Greenwade, L.E.; Overlin, T.K.

1996-12-31

The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

High-Resolution Sonars: What Resolution Do We Need for Target Recognition?

Directory of Open Access Journals (Sweden)

Pailhas Yan

2010-01-01

Full Text Available Target recognition in sonar imagery has long been an active research area in the maritime domain, especially in the mine-counter measure context. Recently it has received even more attention as new sensors with increased resolution have been developed; new threats to critical maritime assets and a new paradigm for target recognition based on autonomous platforms have emerged. With the recent introduction of Synthetic Aperture Sonar systems and high-frequency sonars, sonar resolution has dramatically increased and noise levels decreased. Sonar images are distance images but at high resolution they tend to appear visually as optical images. Traditionally algorithms have been developed specifically for imaging sonars because of their limited resolution and high noise levels. With high-resolution sonars, algorithms developed in the image processing field for natural images become applicable. However, the lack of large datasets has hampered the development of such algorithms. Here we present a fast and realistic sonar simulator enabling development and evaluation of such algorithms.We develop a classifier and then analyse its performances using our simulated synthetic sonar images. Finally, we discuss sensor resolution requirements to achieve effective classification of various targets and demonstrate that with high resolution sonars target highlight analysis is the key for target recognition.

The origin of RX J1856.5-3754 and RX J0720.4-3125 - updated using new parallax measurements

Science.gov (United States)

Tetzlaff, N.; Eisenbeiss, T.; Neuhäuser, R.; Hohle, M. M.

2011-10-01

RX J1856.5-3754 and RX J0720.4-3125 are the only young isolated radio-quiet neutron stars (NSs) for which trigonometric parallaxes were measured. Due to detection of their thermal emission in X-rays, they are important to study NS cooling and to probe theoretical cooling models. Hence, a precise determination of their age is essential. Recently, new parallax measurements of RX J1856.5-3754 and RX J0720.4-3125 were obtained. Considering that NSs may originate from binary systems that got disrupted due to an asymmetric supernova, we attempt to identify runaway stars which may have been former companions to the NS progenitors. Such an identification would strongly support a particular birth scenario with time and place. We trace back each NS, runaway star and the centres of possible birth associations (assuming that most NSs are ejected directly from their parent association) to find close encounters. The kinematic age is then given by the time since the encounter. We use Monte Carlo simulations to account for observational uncertainties and evaluate the outcome statistically. Using the most recent parallax measurement of 8.16 ± 0.80 mas for RX J1856.5-3754 by Walter et al., we find that it originated in the Upper Scorpius association 0.46 ± 0.05 Myr ago. This kinematic age is slightly larger than the value we reported earlier (0.3 Myr) using the old parallax value of 5.6 ± 0.6 mas by Kaplan. Our result is strongly supported by its current radial velocity which we predict to be 6+19- 20 km s-1. This implies an inclination angle to the line of sight of 88°± 6° consistent with estimates by van Kerkwijk & Kulkarni from the bow shock. No suitable runaway star was found to be a potential former companion of RX J1856.5-3754. Making use of a recent parallax measurement for RX J0720.4-3125 of 3.6 ± 1.6 mas by Eisenbeiss, we find that this NS was possibly born in Trumpler 10 0.85 ± 0.15 Myr ago. This kinematic age is somewhat larger than the one obtained using the old

Motion video analysis using planar parallax

Science.gov (United States)

Sawhney, Harpreet S.

1994-04-01

Motion and structure analysis in video sequences can lead to efficient descriptions of objects and their motions. Interesting events in videos can be detected using such an analysis--for instance independent object motion when the camera itself is moving, figure-ground segregation based on the saliency of a structure compared to its surroundings. In this paper we present a method for 3D motion and structure analysis that uses a planar surface in the environment as a reference coordinate system to describe a video sequence. The motion in the video sequence is described as the motion of the reference plane, and the parallax motion of all the non-planar components of the scene. It is shown how this method simplifies the otherwise hard general 3D motion analysis problem. In addition, a natural coordinate system in the environment is used to describe the scene which can simplify motion based segmentation. This work is a part of an ongoing effort in our group towards video annotation and analysis for indexing and retrieval. Results from a demonstration system being developed are presented.

Ultra-high resolution optical coherence tomography for encapsulation quality inspection

KAUST Repository

Czajkowski, Jakub

2011-08-28

We present the application of ultra-high resolution optical coherence tomography (UHR-OCT) in evaluation of thin, protective films used in printed electronics. Two types of sample were investigated: microscopy glass and organic field effect transistor (OFET) structure. Samples were coated with thin (1-3 μm) layer of parylene C polymer. Measurements were done using experimental UHR-OCT device based on a Kerr-lens mode locked Ti: sapphire femtosecond laser, photonic crystal fibre and modified, free-space Michelson interferometer. Submicron resolution offered by the UHR-OCT system applied in the study enables registration of both interfaces of the thin encapsulation layer. Complete, volumetric characterisation of protective layers is presented, demonstrating possibility to use OCT for encapsulation quality inspection. © Springer-Verlag 2011.

Compressed sensing cine imaging with high spatial or high temporal resolution for analysis of left ventricular function.

Science.gov (United States)

Goebel, Juliane; Nensa, Felix; Schemuth, Haemi P; Maderwald, Stefan; Gratz, Marcel; Quick, Harald H; Schlosser, Thomas; Nassenstein, Kai

2016-08-01

To assess two compressed sensing cine magnetic resonance imaging (MRI) sequences with high spatial or high temporal resolution in comparison to a reference steady-state free precession cine (SSFP) sequence for reliable quantification of left ventricular (LV) volumes. LV short axis stacks of two compressed sensing breath-hold cine sequences with high spatial resolution (SPARSE-SENSE HS: temporal resolution: 40 msec, in-plane resolution: 1.0 × 1.0 mm(2) ) and high temporal resolution (SPARSE-SENSE HT: temporal resolution: 11 msec, in-plane resolution: 1.7 × 1.7 mm(2) ) and of a reference cine SSFP sequence (standard SSFP: temporal resolution: 40 msec, in-plane resolution: 1.7 × 1.7 mm(2) ) were acquired in 16 healthy volunteers on a 1.5T MR system. LV parameters were analyzed semiautomatically twice by one reader and once by a second reader. The volumetric agreement between sequences was analyzed using paired t-test, Bland-Altman plots, and Passing-Bablock regression. Small differences were observed between standard SSFP and SPARSE-SENSE HS for stroke volume (SV; -7 ± 11 ml; P = 0.024), ejection fraction (EF; -2 ± 3%; P = 0.019), and myocardial mass (9 ± 9 g; P = 0.001), but not for end-diastolic volume (EDV; P = 0.079) and end-systolic volume (ESV; P = 0.266). No significant differences were observed between standard SSFP and SPARSE-SENSE HT regarding EDV (P = 0.956), SV (P = 0.088), and EF (P = 0.103), but for ESV (3 ± 5 ml; P = 0.039) and myocardial mass (8 ± 10 ml; P = 0.007). Bland-Altman analysis showed good agreement between the sequences (maximum bias ≤ -8%). Two compressed sensing cine sequences, one with high spatial resolution and one with high temporal resolution, showed good agreement with standard SSFP for LV volume assessment. J. Magn. Reson. Imaging 2016;44:366-374. © 2016 Wiley Periodicals, Inc.

Porous carbon-free SnSb anodes for high-performance Na-ion batteries

Science.gov (United States)

Choi, Jeong-Hee; Ha, Choong-Wan; Choi, Hae-Young; Seong, Jae-Wook; Park, Cheol-Min; Lee, Sang-Min

2018-05-01

A simple melt-spinning/chemical-etching process is developed to create porous carbon-free SnSb anodes. Sodium ion batteries (SIBs) incorporating these anodes exhibit excellent electrochemical performances by accomodating large volume changes during repeated cycling. The porous carbon-free SnSb anode produced by the melt-spinning/chemical-etching process shows a high reversible capacity of 481 mAh g-1, high ICE of 80%, stable cyclability with a high capacity retention of 99% after 100 cycles, and a fast rate capability of 327 mAh g-1 at 4C-rate. Ex-situ X-ray diffraction and high resolution-transmission electron microscopy analyses demonstrate that the synthesized porous carbon-free SnSb anodes involve the highly reversible reaction with sodium through the conversion and recombination reactions during sodiation/desodiation process. The novel and simple melt-spinning/chemical-etching synthetic process represents a technological breakthrough in the commercialization of Na alloy-able anodes for SIBs.

Map-based trigonometric parallaxes of open clusters - The Pleiades

Science.gov (United States)

Gatewood, George; Castelaz, Michael; Han, Inwoo; Persinger, Timothy; Stein, John

1990-01-01

The multichannel astrometric photometer and Thaw refractor of the University of Pittsburgh's Allegheny Observatory have been used to determine the trigonometric parallax of the Pleiades star cluster. The distance determined, 150 with a standard error of 18 parsecs, places the cluster slightly farther away than generally accepted. This suggests that the basis of many estimations of the cosmic distance scale is approximately 20 percent short. The accuracy of the determination is limited by the number and choice of reference stars. With careful attention to the selection of reference stars in several Pleiades regions, it should be possible to examine differences in the photometric and trigonometric modulus at a precision of 0.1 magnitudes.

Pinhole diffraction holography for fabrication of high-resolution Fresnel zone plates.

Science.gov (United States)

Sarkar, Sankha S; Solak, Harun H; David, Christian; van der Veen, J Friso

2014-01-27

Fresnel zone plates (FZPs) play an essential role in high spatial resolution x-ray imaging and analysis of materials in many fields. These diffractive lenses are commonly made by serial writing techniques such as electron beam or focused ion beam lithography. Here we show that pinhole diffraction holography has potential to generate FZP patterns that are free from aberrations and imperfections that may be present in alternative fabrication techniques. In this presented method, FZPs are fabricated by recording interference pattern of a spherical wave generated by diffraction through a pinhole, illuminated with coherent plane wave at extreme ultraviolet (EUV) wavelength. Fundamental and practical issues involved in formation and recording of the interference pattern are considered. It is found that resolution of the produced FZP is directly related to the diameter of the pinhole used and the pinhole size cannot be made arbitrarily small as the transmission of EUV or x-ray light through small pinholes diminishes due to poor refractive index contrast found between materials in these spectral ranges. We also find that the practical restrictions on exposure time due to the light intensity available from current sources directly imposes a limit on the number of zones that can be printed with this method. Therefore a trade-off between the resolution and the FZP diameter exists. Overall, we find that this method can be used to fabricate aberration free FZPs down to a resolution of about 10 nm.

An Efficient Bundle Adjustment Model Based on Parallax Parametrization for Environmental Monitoring

Science.gov (United States)

Chen, R.; Sun, Y. Y.; Lei, Y.

2017-12-01

With the rapid development of Unmanned Aircraft Systems (UAS), more and more research fields have been successfully equipped with this mature technology, among which is environmental monitoring. One difficult task is how to acquire accurate position of ground object in order to reconstruct the scene more accurate. To handle this problem, we combine bundle adjustment method from Photogrammetry with parallax parametrization from Computer Vision to create a new method call APCP (aerial polar-coordinate photogrammetry). One impressive advantage of this method compared with traditional method is that the 3-dimensional point in space is represented using three angles (elevation angle, azimuth angle and parallax angle) rather than the XYZ value. As the basis for APCP, bundle adjustment could be used to optimize the UAS sensors' pose accurately, reconstruct the 3D models of environment, thus serving as the criterion of accurate position for monitoring. To verity the effectiveness of the proposed method, we test on several UAV dataset obtained by non-metric digital cameras with large attitude angles, and we find that our methods could achieve 1 or 2 times better efficiency with no loss of accuracy than traditional ones. For the classical nonlinear optimization of bundle adjustment model based on the rectangular coordinate, it suffers the problem of being seriously dependent on the initial values, making it unable to converge fast or converge to a stable state. On the contrary, APCP method could deal with quite complex condition of UAS when conducting monitoring as it represent the points in space with angles, including the condition that the sequential images focusing on one object have zero parallax angle. In brief, this paper presents the parameterization of 3D feature points based on APCP, and derives a full bundle adjustment model and the corresponding nonlinear optimization problems based on this method. In addition, we analyze the influence of convergence and

CAN THE MASSES OF ISOLATED PLANETARY-MASS GRAVITATIONAL LENSES BE MEASURED BY TERRESTRIAL PARALLAX?

Energy Technology Data Exchange (ETDEWEB)

Freeman, M.; Botzler, C. S.; Bray, J. C.; Cherrie, J. M.; Rattenbury, N. J. [Department of Physics, University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Philpott, L. C. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada); Abe, F.; Muraki, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Albrow, M. D. [Department of Physics and Astronomy, University of Canterbury, P.O. Box 4800, Christchurch 8020 (New Zealand); Bennett, D. P. [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Bond, I. A. [Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330 (New Zealand); Christie, G. W.; Natusch, T. [Auckland Observatory, PO Box 180, Royal Oak, Auckland 1345 (New Zealand); Dionnet, Z. [Université d' Orsay, bat 470, F-91400 Orsay (France); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Han, C. [Department of Physics, Chungbuk National University, 410 Seongbong-Rho, Hungduk-Gu, Chongju 371-763 (Korea, Republic of); Heyrovský, D. [Institute of Theoretical Physics, Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague (Czech Republic); McCormick, J. M. [Farm Cove Observatory, 2/24 Rapallo Place, Pakuranga, Auckland 2012 (New Zealand); Moorhouse, D. M. [Kumeu Observatory, Kumeu (New Zealand); Skowron, J., E-mail: mfre070@aucklanduni.ac.nz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478, Warszawa (Poland); and others

2015-02-01

Recently Sumi et al. reported evidence for a large population of planetary-mass objects (PMOs) that are either unbound or orbit host stars in orbits ≥10 AU. Their result was deduced from the statistical distribution of durations of gravitational microlensing events observed by the MOA collaboration during 2006 and 2007. Here we study the feasibility of measuring the mass of an individual PMO through microlensing by examining a particular event, MOA-2011-BLG-274. This event was unusual as the duration was short, the magnification high, the source-size effect large, and the angular Einstein radius small. Also, it was intensively monitored from widely separated locations under clear skies at low air masses. Choi et al. concluded that the lens of the event may have been a PMO but they did not attempt a measurement of its mass. We report here a re-analysis of the event using re-reduced data. We confirm the results of Choi et al. and attempt a measurement of the mass and distance of the lens using the terrestrial parallax effect. Evidence for terrestrial parallax is found at a 3σ level of confidence. The best fit to the data yields the mass and distance of the lens as 0.80 ± 0.30 M {sub J} and 0.80 ± 0.25 kpc respectively. We exclude a host star to the lens out to a separation ∼40 AU. Drawing on our analysis of MOA-2011-BLG-274 we propose observational strategies for future microlensing surveys to yield sharper results on PMOs including those down to super-Earth mass.

Berkeley High-Resolution Ball

International Nuclear Information System (INIS)

Diamond, R.M.

1984-10-01

Criteria for a high-resolution γ-ray system are discussed. Desirable properties are high resolution, good response function, and moderate solid angle so as to achieve not only double- but triple-coincidences with good statistics. The Berkeley High-Resolution Ball involved the first use of bismuth germanate (BGO) for anti-Compton shield for Ge detectors. The resulting compact shield permitted rather close packing of 21 detectors around a target. In addition, a small central BGO ball gives the total γ-ray energy and multiplicity, as well as the angular pattern of the γ rays. The 21-detector array is nearly complete, and the central ball has been designed, but not yet constructed. First results taken with 9 detector modules are shown for the nucleus 156 Er. The complex decay scheme indicates a transition from collective rotation (prolate shape) to single- particle states (possibly oblate) near spin 30 h, and has other interesting features

Development and test of a high-resolution detector for synchrotron radiation imaging; Entwicklung und Test eines hochaufloesenden Detektors zur Bildgebung mit Synchrotronstrahlung

Energy Technology Data Exchange (ETDEWEB)

Ruebsamen, Oliver

2011-07-01

For medical imaging with x-rays, especially coronary angiography in vivo, high position resolution detectors are needed, thereby being able to deliver a contrast better than 1% and a readout speed faster than milliseconds. Since coronary angiography uses a contrast agent like iodine or gadolinium, high energy photons up to 51 keV are needed for imaging. The k-edge subtraction method allows visualizing small vessels because of the sharp jump of absorption at the k-edge of the contrast agent and the almost constant absorption of the surrounding tissue and bone, as well as the measurement of the concentration of the contrast agent to explore heart dynamics. Various detectors and detector materials are in use or development to match these conditions. Solid state Si-, Ge-, CdZnTe-, CdMnTe- or CdTe-seminconductor detectors are used or tested for imaging, each of them having different physical and/or technical problems which prevent to meet the required specifications. These problems are low absorption efficiency (Si) and reduced position resolution if scintillators are used, cooling and poor resolution (Ge) and charge spread along many pixels and technical problems to manufacture a detector chip (CdZnTe, CdMnTe, CdTe). The approach made in this work is a gas filled ionization chamber, built as a integrating line detector. In general, ionization chambers always suffer from poor absorption efficiency, but this can be overcome using the noble Gases Ar, Kr or Xe at very high gas pressures around 50 bar and relatively long (in the range of cm) anode strips. This design is critical for parallax effects, so an x-ray beam with a very small beam divergence is needed. This requirement in combination with the desired contrast and timing resolution can only be achieved by synchrotron light sources of the third generation, like the DORIS ring at DESY, Hamburg or the ESR in Grenoble. A different problem of ionization chambers is fluorescence photons, which produce a background signal

Three-dimensional true FISP for high-resolution imaging of the whole brain

International Nuclear Information System (INIS)

Schmitz, B.; Hagen, T.; Reith, W.

2003-01-01

While high-resolution T1-weighted sequences, such as three-dimensional magnetization-prepared rapid gradient-echo imaging, are widely available, there is a lack of an equivalent fast high-resolution sequence providing T2 contrast. Using fast high-performance gradient systems we show the feasibility of three-dimensional true fast imaging with steady-state precession (FISP) to fill this gap. We applied a three-dimensional true-FISP protocol with voxel sizes down to 0.5 x 0.5 x 0.5 mm and acquisition times of approximately 8 min on a 1.5-T Sonata (Siemens, Erlangen, Germany) magnetic resonance scanner. The sequence was included into routine brain imaging protocols for patients with cerebrospinal-fluid-related intracranial pathology. Images from 20 patients and 20 healthy volunteers were evaluated by two neuroradiologists with respect to diagnostic image quality and artifacts. All true-FISP scans showed excellent imaging quality free of artifacts in patients and volunteers. They were valuable for the assessment of anatomical and pathologic aspects of the included patients. High-resolution true-FISP imaging is a valuable adjunct for the exploration and neuronavigation of intracranial pathologies especially if cerebrospinal fluid is involved. (orig.)

High-resolution inner-shell spectroscopies of free atoms and molecules using soft-x-ray beamlines at the third-generation synchrotron radiation sources

International Nuclear Information System (INIS)

Ueda, Kiyoshi

2003-01-01

This article reviews the current status of inner-shell spectroscopies of free atoms and molecules using high-resolution soft-x-ray monochromators installed in the soft-x-ray beamlines at the third-generation synchrotron radiation facilities. Beamlines and endstations devoted to atomic and molecular inner-shell spectroscopies and various types of experimental techniques, such as ion yield spectroscopy, resonant photoemission spectroscopy and multiple-coincidence momentum imaging, are described. Experimental results for K-shell excitation of Ne, O K-shell excitation of H 2 O and CO 2 , C K-shell excitation and ionization of CO 2 and B K-shell excitation of BF 3 , obtained at beamline 27SU of SPring-8 in Japan, are discussed as examples of atomic and molecular inner-shell spectroscopies using the third-generation synchrotron radiation sources. (topical review)

A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.

Science.gov (United States)

Ratzlaff, Michael; Nawrot, Mark

2016-09-01

The visual system uses an extraretinal pursuit eye movement signal to disambiguate the perception of depth from motion parallax. Visual motion in the same direction as the pursuit is perceived nearer in depth while visual motion in the opposite direction as pursuit is perceived farther in depth. This explanation of depth sign applies to either an allocentric frame of reference centered on the fixation point or an egocentric frame of reference centered on the observer. A related problem is that of depth order when two stimuli have a common direction of motion. The first psychophysical study determined whether perception of egocentric depth order is adequately explained by a model employing an allocentric framework, especially when the motion parallax stimuli have common rather than divergent motion. A second study determined whether a reversal in perceived depth order, produced by a reduction in pursuit velocity, is also explained by this model employing this allocentric framework. The results show than an allocentric model can explain both the egocentric perception of depth order with common motion and the perceptual depth order reversal created by a reduction in pursuit velocity. We conclude that an egocentric model is not the only explanation for perceived depth order in these common motion conditions. © The Author(s) 2016.

High-resolution characterization of sequence signatures due to non-random cleavage of cell-free DNA.

Science.gov (United States)

Chandrananda, Dineika; Thorne, Natalie P; Bahlo, Melanie

2015-06-17

High-throughput sequencing of cell-free DNA fragments found in human plasma has been used to non-invasively detect fetal aneuploidy, monitor organ transplants and investigate tumor DNA. However, many biological properties of this extracellular genetic material remain unknown. Research that further characterizes circulating DNA could substantially increase its diagnostic value by allowing the application of more sophisticated bioinformatics tools that lead to an improved signal to noise ratio in the sequencing data. In this study, we investigate various features of cell-free DNA in plasma using deep-sequencing data from two pregnant women (>70X, >50X) and compare them with matched cellular DNA. We utilize a descriptive approach to examine how the biological cleavage of cell-free DNA affects different sequence signatures such as fragment lengths, sequence motifs at fragment ends and the distribution of cleavage sites along the genome. We show that the size distributions of these cell-free DNA molecules are dependent on their autosomal and mitochondrial origin as well as the genomic location within chromosomes. DNA mapping to particular microsatellites and alpha repeat elements display unique size signatures. We show how cell-free fragments occur in clusters along the genome, localizing to nucleosomal arrays and are preferentially cleaved at linker regions by correlating the mapping locations of these fragments with ENCODE annotation of chromatin organization. Our work further demonstrates that cell-free autosomal DNA cleavage is sequence dependent. The region spanning up to 10 positions on either side of the DNA cleavage site show a consistent pattern of preference for specific nucleotides. This sequence motif is present in cleavage sites localized to nucleosomal cores and linker regions but is absent in nucleosome-free mitochondrial DNA. These background signals in cell-free DNA sequencing data stem from the non-random biological cleavage of these fragments. This

High-Resolution PET Detector. Final report

International Nuclear Information System (INIS)

Karp, Joel

2014-01-01

The objective of this project was to develop an understanding of the limits of performance for a high resolution PET detector using an approach based on continuous scintillation crystals rather than pixelated crystals. The overall goal was to design a high-resolution detector, which requires both high spatial resolution and high sensitivity for 511 keV gammas. Continuous scintillation detectors (Anger cameras) have been used extensively for both single-photon and PET scanners, however, these instruments were based on NaI(Tl) scintillators using relatively large, individual photo-multipliers. In this project we investigated the potential of this type of detector technology to achieve higher spatial resolution through the use of improved scintillator materials and photo-sensors, and modification of the detector surface to optimize the light response function.We achieved an average spatial resolution of 3-mm for a 25-mm thick, LYSO continuous detector using a maximum likelihood position algorithm and shallow slots cut into the entrance surface

GENERATION OF HIGH RESOLUTION AND HIGH PRECISION ORTHORECTIFIED ROAD IMAGERY FROM MOBILE MAPPING SYSTEM

Directory of Open Access Journals (Sweden)

M. Sakamoto

2012-07-01

Full Text Available In this paper, a novel technique to generate a high resolution and high precision Orthorectified Road Imagery (ORI by using spatial information acquired from a Mobile Mapping System (MMS is introduced. The MMS was equipped with multiple sensors such as GPS, IMU, odometer, 2-6 digital cameras and 2-4 laser scanners. In this study, a Triangulated Irregular Network (TIN based approach, similar to general aerial photogrammetry, was adopted to build a terrain model in order to generate ORI with high resolution and high geometric precision. Compared to aerial photogrammetry, there are several issues that are needed to be addressed. ORI is generated by merging multiple time sequence images of a short section. Hence, the influence of occlusion due to stationary objects, such as telephone poles, trees, footbridges, or moving objects, such as vehicles, pedestrians are very significant. Moreover, influences of light falloff at the edges of cameras, tone adjustment among images captured from different cameras or a round trip data acquisition of the same path, and time lag between image exposure and laser point acquisition also need to be addressed properly. The proposed method was applied to generate ORI with 1 cm resolution, from the actual MMS data sets. The ORI generated by the proposed technique was more clear, occlusion free and with higher resolution compared to the conventional orthorectified coloured point cloud imagery. Moreover, the visual interpretation of road features from the ORI was much easier. In addition, the experimental results also validated the effectiveness of proposed radiometric corrections. In occluded regions, the ORI was compensated by using other images captured from different angles. The validity of the image masking process, in the occluded regions, was also ascertained.

Southern high-velocity stars

International Nuclear Information System (INIS)

Augensen, H.J.; Buscombe, W.

1978-01-01

Using the model of the Galaxy presented by Eggen, Lynden-Bell and Sandage (1962), plane galactic orbits have been calculated for 800 southern high-velocity stars which possess parallax, proper motion, and radial velocity data. The stars with trigonometric parallaxes were selected from Buscombe and Morris (1958), supplemented by more recent spectroscopic data. Photometric parallaxes from infrared color indices were used for bright red giants studied by Eggen (1970), and for red dwarfs for which Rodgers and Eggen (1974) determined radial velocities. A color-color diagram based on published values of (U-B) and (B-V) for most of these stars is shown. (Auth.)

High resolution imaging detectors and applications

CERN Document Server

Saha, Swapan K

2015-01-01

Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in astronomical observations, and since the explanation of the photoelectric effect by Albert Einstein, the technology has evolved rather fast. The present-day technology has made it possible to develop large-format complementary metal oxide–semiconductor (CMOS) and charge-coupled device (CCD) array mosaics, orthogonal transfer CCDs, electron-multiplication CCDs, electron-avalanche photodiode arrays, and quantum-well infrared (IR) photon detectors. The requirements to develop artifact-free photon shot noise-limited images are higher sensitivity and quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions, and higher spectral bandwidth. This book aims to address such systems, technologies and design, evaluation and calibration, control...

Irrational free field resolutions for W(sl(n)) and extended Sugawara construction

International Nuclear Information System (INIS)

Niedermaier, M.

1991-03-01

The existence of Miura-type free field realizations is established for the extended conformal algebras W(sl(n)) at irrational values of the screening parameter. The problem of the 'closure' of the algebra is reduced to a finite dimensional quantum group problem. The structure of the Fock space resolution and the character formulae are obtained for the irreducible modules. They are shown to be isomorphic to the space of sl(n) singlets in sl(n) affine affine level 1 modules. The isomorphism is given by the Φβγ free field realization of sl(n). (orig.)

High resolution sequence stratigraphy in China

International Nuclear Information System (INIS)

Zhang Shangfeng; Zhang Changmin; Yin Yanshi; Yin Taiju

2008-01-01

Since high resolution sequence stratigraphy was introduced into China by DENG Hong-wen in 1995, it has been experienced two development stages in China which are the beginning stage of theory research and development of theory research and application, and the stage of theoretical maturity and widely application that is going into. It is proved by practices that high resolution sequence stratigraphy plays more and more important roles in the exploration and development of oil and gas in Chinese continental oil-bearing basin and the research field spreads to the exploration of coal mine, uranium mine and other strata deposits. However, the theory of high resolution sequence stratigraphy still has some shortages, it should be improved in many aspects. The authors point out that high resolution sequence stratigraphy should be characterized quantitatively and modelized by computer techniques. (authors)

Development of AMS high resolution injector system

International Nuclear Information System (INIS)

Bao Yiwen; Guan Xialing; Hu Yueming

2008-01-01

The Beijing HI-13 tandem accelerator AMS high resolution injector system was developed. The high resolution energy achromatic system consists of an electrostatic analyzer and a magnetic analyzer, which mass resolution can reach 600 and transmission is better than 80%. (authors)

Full parallax three-dimensional computer generated hologram with occlusion effect using ray casting technique

International Nuclear Information System (INIS)

Zhang, Hao; Tan, Qiaofeng; Jin, Guofan

2013-01-01

Holographic display is capable of reconstructing the whole optical wave field of a three-dimensional (3D) scene. It is the only one among all the 3D display techniques that can produce all the depth cues. With the development of computing technology and spatial light modulators, computer generated holograms (CGHs) can now be used to produce dynamic 3D images of synthetic objects. Computation holography becomes highly complicated and demanding when it is employed to produce real 3D images. Here we present a novel algorithm for generating a full parallax 3D CGH with occlusion effect, which is an important property of 3D perception, but has often been neglected in fully computed hologram synthesis. The ray casting technique, which is widely used in computer graphics, is introduced to handle the occlusion issue of CGH computation. Horizontally and vertically distributed rays are projected from each hologram sample to the 3D objects to obtain the complex amplitude distribution. The occlusion issue is handled by performing ray casting calculations to all the hologram samples. The proposed algorithm has no restriction on or approximation to the 3D objects, and hence it can produce reconstructed images with correct shading effect and no visible artifacts. Programmable graphics processing unit (GPU) is used to perform parallel calculation. This is made possible because each hologram sample belongs to an independent operation. To demonstrate the performance of our proposed algorithm, an optical experiment is performed to reconstruct the 3D scene by using a phase-only spatial light modulator. We can easily perceive the accommodation cue by focusing our eyes on different depths of the scene and the motion parallax cue with occlusion effect by moving our eyes around. The experiment result confirms that the CGHs produced by our algorithm can successfully reconstruct 3D images with all the depth cues.

Resolution enhancement of low quality videos using a high-resolution frame

NARCIS (Netherlands)

Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

2006-01-01

This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of

Statistical parallaxes and the fundamental distance scale

International Nuclear Information System (INIS)

Clube, S.V.M.; Dawe, J.A.

1980-01-01

The statistical parallax technique of Paper I is used to derive an absolute magnitude of = 1.0 +- 0.25 mag for the set of 59 high ΔS RR Lyrae stars of Clube and Jones. Taken in conjunction with the kinematical properties of RR Lyrae variables and other field stars, this magnitude leads to the following values for the principal galactic constants: R 0 = approximately 7 +- 1 kpc, A = approximately 16 +- 3 km s -1 kpc -1 , B = approximately -20 +- 5 km s -1 kpc -1 and theta 0 = approximately 250 +- 40 km s -1 . The technique is also applied to Wielen's set of 45 Cepheids and no correction of the galactic Cepheid distance scale based on cluster members is found to be necessary. These sets of results are consistent if, as has been shown elsewhere, the kinematic model used to analyse the motions of young stars takes account of radial motions in the Galaxy. The distances to the Magellanic Clouds given by RR Lyraes and Cepheids are in conflict however. Although the evidence suggesting a general similarity of halo RR Lyraes in our Galaxy and the Magellanic Clouds is not absolutely conclusive, it is suggested that the conflict may be resolved by use of a colour term in the P-L-C relation for Cepheids which is much less than that adopted by Sandage and Tammann. The conclusions are in general accord with recent proposals seeking to increase the Hubble constant to around 80 km s -1 Mpc -1 . (author)

High resolution, high speed ultrahigh vacuum microscopy

International Nuclear Information System (INIS)

Poppa, Helmut

2004-01-01

The history and future of transmission electron microscopy (TEM) is discussed as it refers to the eventual development of instruments and techniques applicable to the real time in situ investigation of surface processes with high resolution. To reach this objective, it was necessary to transform conventional high resolution instruments so that an ultrahigh vacuum (UHV) environment at the sample site was created, that access to the sample by various in situ sample modification procedures was provided, and that in situ sample exchanges with other integrated surface analytical systems became possible. Furthermore, high resolution image acquisition systems had to be developed to take advantage of the high speed imaging capabilities of projection imaging microscopes. These changes to conventional electron microscopy and its uses were slowly realized in a few international laboratories over a period of almost 40 years by a relatively small number of researchers crucially interested in advancing the state of the art of electron microscopy and its applications to diverse areas of interest; often concentrating on the nucleation, growth, and properties of thin films on well defined material surfaces. A part of this review is dedicated to the recognition of the major contributions to surface and thin film science by these pioneers. Finally, some of the important current developments in aberration corrected electron optics and eventual adaptations to in situ UHV microscopy are discussed. As a result of all the path breaking developments that have led to today's highly sophisticated UHV-TEM systems, integrated fundamental studies are now possible that combine many traditional surface science approaches. Combined investigations to date have involved in situ and ex situ surface microscopies such as scanning tunneling microscopy/atomic force microscopy, scanning Auger microscopy, and photoemission electron microscopy, and area-integrating techniques such as x-ray photoelectron

A high resolution solar atlas for fluorescence calculations

Science.gov (United States)

Hearn, M. F.; Ohlmacher, J. T.; Schleicher, D. G.

1983-01-01

The characteristics required of a solar atlas to be used for studying the fluorescence process in comets are examined. Several sources of low resolution data were combined to provide an absolutely calibrated spectrum from 2250 A to 7000A. Three different sources of high resolution data were also used to cover this same spectral range. The low resolution data were then used to put each high resolution spectrum on an absolute scale. The three high resolution spectra were then combined in their overlap regions to produce a single, absolutely calibrated high resolution spectrum over the entire spectral range.

Electron Temperatures in W51 Complex from High Resolution, Low ...

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... We have made continuum radio observations of these HII regions of the W51 complex at 240, 610, 1060 and 1400 MHz using GMRT with lower resolution (20'' × 15'') at the lowest frequency. The observed spectra of the prominent thermal subcomponents of W51 have been fitted to a free-free emission ...

High-resolution SPECT for small-animal imaging

International Nuclear Information System (INIS)

Qi Yujin

2006-01-01

This article presents a brief overview of the development of high-resolution SPECT for small-animal imaging. A pinhole collimator has been used for high-resolution animal SPECT to provide better spatial resolution and detection efficiency in comparison with a parallel-hole collimator. The theory of imaging characteristics of the pinhole collimator is presented and the designs of the pinhole aperture are discussed. The detector technologies used for the development of small-animal SPECT and the recent advances are presented. The evolving trend of small-animal SPECT is toward a multi-pinhole and a multi-detector system to obtain a high resolution and also a high detection efficiency. (authors)

All solution-processed high-resolution bottom-contact transparent metal-oxide thin film transistors

International Nuclear Information System (INIS)

Park, Sung Kyu; Kim, Yong-Hoon; Han, Jeong-In

2009-01-01

We report all solution-processed high-resolution bottom-contact indium-gallium-zinc-oxide (IGZO) thin film transistors (TFTs) using a simple surface patterning and dip-casting process. High-resolution nanoparticulate Ag source/drain electrodes and a sol-gel processed IGZO semiconductor were deposited by a simple dip-casting along with a photoresist-free, non-relief-pattern lithographic process. The deposited Ag and IGZO solution can be steered into the desired hydrophilic areas by a low surface energy self-assembled monolayer, resulting in source/drain electrodes and semiconducting layer, respectively. The all solution-processed bottom-contact IGZO TFTs including a channel length of 10 μm typically showed a mobility range 0.05-0.2 cm 2 V -1 s -1 with an on/off ratio of more than 10 6 .

Noise-free high-efficiency photon-number-resolving detectors

International Nuclear Information System (INIS)

Rosenberg, Danna; Lita, Adriana E.; Miller, Aaron J.; Nam, Sae Woo

2005-01-01

High-efficiency optical detectors that can determine the number of photons in a pulse of monochromatic light have applications in a variety of physics studies, including post-selection-based entanglement protocols for linear optics quantum computing and experiments that simultaneously close the detection and communication loopholes of Bell's inequalities. Here we report on our demonstration of fiber-coupled, noise-free, photon-number-resolving transition-edge sensors with 88% efficiency at 1550 nm. The efficiency of these sensors could be made even higher at any wavelength in the visible and near-infrared spectrum without resulting in a higher dark-count rate or degraded photon-number resolution

A SIMULTANEOUS MULTI-PROBE DETECTION LABEL-FREE OPTICAL-RESOLUTION PHOTOACOUSTIC MICROSCOPY TECHNIQUE BASED ON MICROCAVITY TRANSDUCER

Directory of Open Access Journals (Sweden)

YONGBO WU

2013-07-01

Full Text Available We demonstrate the feasibility of simultaneous multi-probe detection for an optical-resolution photoacoustic microscopy (OR-PAM system. OR-PAM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth. OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules. However, given the inadequate absorption of some biomolecules, detection sensitivity at the same incident intensity requires improvement. In this study, a modulated continuous wave with power density less than 3 mW/cm2 (1/4 of the ANSI safety limit excited the weak photoacoustic (PA signals of biological cells. A microcavity transducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid; air pressure variation is inversely proportional to cavity volume at the same temperature increase. Considering that a PA wave expands in various directions, detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio. Therefore, we employ four detectors to acquire tiny PA signals simultaneously. Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.

High resolution time integration for SN radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2009-01-01

First-order, second-order, and high resolution time discretization schemes are implemented and studied for the discrete ordinates (S N ) equations. The high resolution method employs a rate of convergence better than first-order, but also suppresses artificial oscillations introduced by second-order schemes in hyperbolic partial differential equations. The high resolution method achieves these properties by nonlinearly adapting the time stencil to use a first-order method in regions where oscillations could be created. We employ a quasi-linear solution scheme to solve the nonlinear equations that arise from the high resolution method. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second-order and high resolution converged to the same solution as the first-order with better convergence rates. High resolution is more accurate than first-order and matches or exceeds the second-order method

High tracking resolution detectors. Final Technical Report

International Nuclear Information System (INIS)

Vasile, Stefan; Li, Zheng

2010-01-01

High-resolution tracking detectors based on Active Pixel Sensor (APS) have been valuable tools in Nuclear Physics and High-Energy Physics research, and have contributed to major discoveries. Their integration time, radiation length and readout rate is a limiting factor for the planed luminosity upgrades in nuclear and high-energy physics collider-based experiments. The goal of this program was to demonstrate and develop high-gain, high-resolution tracking detector arrays with faster readout, and shorter radiation length than APS arrays. These arrays may operate as direct charged particle detectors or as readouts of high resolution scintillating fiber arrays. During this program, we developed in CMOS large, high-resolution pixel sensor arrays with integrated readout, and reset at pixel level. Their intrinsic gain, high immunity to surface and moisture damage, will allow operating these detectors with minimal packaging/passivation requirements and will result in radiation length superior to APS. In Phase I, we designed and fabricated arrays with calorimetric output capable of sub-pixel resolution and sub-microsecond readout rate. The technical effort was dedicated to detector and readout structure development, performance verification, as well as to radiation damage and damage annealing.

Geomorphology and vegetation mapping the ice-free terrains of the Western Antarctic Peninsula region using very high resolution imagery from an UAV

Science.gov (United States)

Vieira, G.; Mora, C.; Pina, P.; Bandeira, L.; Hong, S. G.

2014-12-01

The West Antarctic Peninsula (WAP) is one of the Earth's regions with a fastest warming signal since the 1950's with an increase of over +2.5 ºC in MAAT. Significant changes have been reported for glaciers, ice-shelves, sea-ice and also for the permafrost environment. Mapping and monitoring the ice-free areas of the WAP has been until recently limited by the available aerial photo surveys, but also by the scarce high resolution satellite imagery (e.g. QuickBird, WorldView, etc.) that are seriously constrained by the high cloudiness of the region. Recent developments in Unmanned Aerial Vehicles (UAV's), which have seen significant technological advances and price reduction in the last few years, allow for its systematical use for mapping and monitoring in remote environments. In the framework of projects PERMANTAR-3 (PTDC/AAG-GLO/3908/2012 - FCT) and 3DAntártida (Ciência Viva), we complement traditional terrain surveying and mapping, satellite remote sensing (SAR and optical) and D-GPS deformation monitoring, with the application of an UAV. In this communication, we present the results from the application of a Sensefly ebee UAV in mapping the vegetation and geomorphological processes (e.g. sorted circles), as well as for digital elevation model generation in a test site in Barton Pen., King George Isl.. The UAV is a lightweight (ci. 700g) aircraft, with a 96 cm wingspan, which is portable and easy to transport. It allows for up to 40 min flight time, with application of RGB or NIR cameras. We have tested the ebee successfully with winds up to 10 m/s and obtained aerial photos with a ground resolution of 4 cm/pixel. The digital orthophotomaps, high resolution DEM's together with field observations have allowed for deriving geomorphological maps with unprecedented detail and accuracy, providing new insight into the controls on the spatial distribution of geomorphological processes. The talk will focus on the first results from the field surveys of February and

Ultra high resolution tomography

Energy Technology Data Exchange (ETDEWEB)

Haddad, W.S.

1994-11-15

Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

A Simple Approach for Obtaining High Resolution, High Sensitivity ¹H NMR Metabolite Spectra of Biofluids with Limited Mass Supply

Energy Technology Data Exchange (ETDEWEB)

Hu, Jian Zhi; Rommereim, Donald N.; Wind, Robert A.; Minard, Kevin R.; Sears, Jesse A.

2006-11-01

A simple approach is reported that yields high resolution, high sensitivity ¹H NMR spectra of biofluids with limited mass supply. This is achieved by spinning a capillary sample tube containing a biofluid at the magic angle at a frequency of about 80Hz. A 2D pulse sequence called ¹H PASS is then used to produce a high-resolution ¹H NMR spectrum that is free from magnetic susceptibility induced line broadening. With this new approach a high resolution ¹H NMR spectrum of biofluids with a volume less than 1.0 µl can be easily achieved at a magnetic field strength as low as 7.05T. Furthermore, the methodology facilitates easy sample handling, i.e., the samples can be directly collected into inexpensive and disposable capillary tubes at the site of collection and subsequently used for NMR measurements. In addition, slow magic angle spinning improves magnetic field shimming and is especially suitable for high throughput investigations. In this paper first results are shown obtained in a magnetic field of 7.05T on urine samples collected from mice using a modified commercial NMR probe.

Sub-GHz-resolution C-band Nyquist-filtering interleaver on a high-index-contrast photonic integrated circuit.

Science.gov (United States)

Zhuang, Leimeng; Zhu, Chen; Corcoran, Bill; Burla, Maurizio; Roeloffzen, Chris G H; Leinse, Arne; Schröder, Jochen; Lowery, Arthur J

2016-03-21

Modern optical communications rely on high-resolution, high-bandwidth filtering to maximize the data-carrying capacity of fiber-optic networks. Such filtering typically requires high-speed, power-hungry digital processes in the electrical domain. Passive optical filters currently provide high bandwidths with low power consumption, but at the expense of resolution. Here, we present a passive filter chip that functions as an optical Nyquist-filtering interleaver featuring sub-GHz resolution and a near-rectangular passband with 8% roll-off. This performance is highly promising for high-spectral-efficiency Nyquist wavelength division multiplexed (N-WDM) optical super-channels. The chip provides a simple two-ring-resonator-assisted Mach-Zehnder interferometer, which has a sub-cm2 footprint owing to the high-index-contrast Si3N4/SiO2 waveguide, while manifests low wavelength-dependency enabling C-band (> 4 THz) coverage with more than 160 effective free spectral ranges of 25 GHz. This device is anticipated to be a critical building block for spectrally-efficient, chip-scale transceivers and ROADMs for N-WDM super-channels in next-generation optical communication networks.

A high resolution portable spectroscopy system

International Nuclear Information System (INIS)

Kulkarni, C.P.; Vaidya, P.P.; Paulson, M.; Bhatnagar, P.V.; Pande, S.S.; Padmini, S.

2003-01-01

Full text: This paper describes the system details of a High Resolution Portable Spectroscopy System (HRPSS) developed at Electronics Division, BARC. The system can be used for laboratory class, high-resolution nuclear spectroscopy applications. The HRPSS consists of a specially designed compact NIM bin, with built-in power supplies, accommodating a low power, high resolution MCA, and on-board embedded computer for spectrum building and communication. A NIM based spectroscopy amplifier and a HV module for detector bias are integrated (plug-in) in the bin. The system communicates with a host PC via a serial link. Along-with a laptop PC, and a portable HP-Ge detector, the HRPSS offers a laboratory class performance for portable applications

3D high spectral and spatial resolution imaging of ex vivo mouse brain

International Nuclear Information System (INIS)

Foxley, Sean; Karczmar, Gregory S.; Domowicz, Miriam; Schwartz, Nancy

2015-01-01

Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T 2 * -weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T 2 * and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm 3 and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T 2 * -weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in the water resonance that is not

Counterbalancing hydrodynamic sample distortion effects increases resolution of free-flow zone electrophoresis.

Science.gov (United States)

Weber, G; Bauer, J

1998-06-01

On fractionation of highly heterogeneous protein mixtures, optimal resolution was achieved by forcing proteins to migrate through a preestablished pH gradient, until they entered a medium with a pH similar but not equal to their pIs. For this purpose, up to seven different media were pumped through the electrophoresis chamber so that they were flowing adjacently to each other, forming a pH gradient declining stepwise from the cathode to the anode. This gradient had a sufficiently strong band-focusing effect to counterbalance sample distortion effects of the flowing medium as proteins approached their isoelectric medium closer than 0.5 pH units. Continuous free-flow zone electrophoresis (FFZE) with high throughput capability was applicable if proteins did not precipitate or aggregate in these media. If components of heterogeneous protein mixtures had already started to precipitate or aggregate, in a medium with a pH exceeding their pI by more than 0.5 pH units, the application of interval modus and media forming flat pH gradients appeared advantageous.

Metallic magnetic calorimeters for high resolution X-ray spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Krantz, M.; Hengstler, D.; Geist, J.; Schoetz, C.; Hassel, K.; Hendricks, S.; Keller, M.; Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C. [Heidelberg Univ. (Germany). KIP

2015-07-01

We develop microfabricated, energy dispersive particle detector arrays based on metallic magnetic calorimeters (MMCs) for high resolution X-ray spectroscopy to challenge bound-state QED calculations. Our MMCs are operated at about T=30 mK and use a paramagnetic temperature sensor, read-out by a SQUID, to measure the energy deposited by single X-ray photons. We discuss the physics of MMCs, the detector performance and the cryogenic setups for two different detector arrays. We present their microfabrication layouts with focus on challenges like the heatsinking of each pixel of the detector and the overhanging absorbers. The maXs-20 detector is a linear 1x8-pixel array with excellent linearity in its designated energy range up to 20 keV and unsurpassed energy resolution of 1.6 eV for 6 keV x-rays. MaXs-20 operated in a highly portable pulse tube cooled ADR setup has already been used at the EBIT facilities of the MPI-K for new reference measurements of V-like and Ti-like tungsten. The maXs-30 detector currently in development is a 8x8-pixel 2d-array with an active detection area of 16 mm{sup 2} and is designed to detect X-rays up to 50 keV with a designated energy resolution below 5 eV. MaXs-30 will be operated in a cryogen free 3He/4He-dilution refrigerator at the tip of a 40 cm long cold finger at T=20 mK.

High Resolution Elevation Contours

Data.gov (United States)

Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

Energy Technology Data Exchange (ETDEWEB)

Zeng, Ying-Xu [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); Mjøs, Svein Are, E-mail: svein.mjos@kj.uib.no [Department of Chemistry, University of Bergen, PO Box 7803, N-5020 Bergen (Norway); David, Fabrice P.A. [Bioinformatics and Biostatistics Core Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) and Swiss Institute of Bioinformatics (SIB), Lausanne (Switzerland); Schmid, Adrien W. [Proteomics Core Facility, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

2016-03-31

Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

Extension of least squares spectral resolution algorithm to high-resolution lipidomics data

International Nuclear Information System (INIS)

Zeng, Ying-Xu; Mjøs, Svein Are; David, Fabrice P.A.; Schmid, Adrien W.

2016-01-01

Lipidomics, which focuses on the global study of molecular lipids in biological systems, has been driven tremendously by technical advances in mass spectrometry (MS) instrumentation, particularly high-resolution MS. This requires powerful computational tools that handle the high-throughput lipidomics data analysis. To address this issue, a novel computational tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. The algorithm features the customized generation of a lipid compound library and mass spectral library, which covers the major lipid classes such as glycerolipids, glycerophospholipids and sphingolipids. Next, the algorithm performs least squares resolution of spectra and chromatograms based on the theoretical isotope distribution of molecular ions, which enables automated identification and quantification of molecular lipid species. Currently, this methodology supports analysis of both high and low resolution MS as well as liquid chromatography-MS (LC-MS) lipidomics data. The flexibility of the methodology allows it to be expanded to support more lipid classes and more data interpretation functions, making it a promising tool in lipidomic data analysis. - Highlights: • A flexible strategy for analyzing MS and LC-MS data of lipid molecules is proposed. • Isotope distribution spectra of theoretically possible compounds were generated. • High resolution MS and LC-MS data were resolved by least squares spectral resolution. • The method proposed compounds that are likely to occur in the analyzed samples. • The proposed compounds matched results from manual interpretation of fragment spectra.

Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

Science.gov (United States)

Zhu, Wei; Gould, Andrew

2016-06-01

Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.

Improved methods for high resolution electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Taylor, J.R.

1987-04-01

Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

Ultra-high resolution coded wavefront sensor

KAUST Repository

Wang, Congli

2017-06-08

Wavefront sensors and more general phase retrieval methods have recently attracted a lot of attention in a host of application domains, ranging from astronomy to scientific imaging and microscopy. In this paper, we introduce a new class of sensor, the Coded Wavefront Sensor, which provides high spatio-temporal resolution using a simple masked sensor under white light illumination. Specifically, we demonstrate megapixel spatial resolution and phase accuracy better than 0.1 wavelengths at reconstruction rates of 50 Hz or more, thus opening up many new applications from high-resolution adaptive optics to real-time phase retrieval in microscopy.

Controlling laser-induced jet formation for bioprinting mesenchymal stem cells with high viability and high resolution

International Nuclear Information System (INIS)

Ali, Muhammad; Pages, Emeline; Ducom, Alexandre; Fontaine, Aurelien; Guillemot, Fabien

2014-01-01

Laser-assisted bioprinting is a versatile, non-contact, nozzle-free printing technique which has demonstrated high potential for cell printing with high resolution. Improving cell viability requires determining printing conditions which minimize shear stress for cells within the jet and cell impact at droplet landing. In this context, this study deals with laser-induced jet dynamics to determine conditions from which jets arise with minimum kinetic energies. The transition from a sub-threshold regime to jetting regime has been associated with a geometrical parameter (vertex angle) which can be harnessed to print mesenchymal stem cells with high viability using slow jet conditions. Finally, hydrodynamic jet stability is also studied for higher laser pulse energies which give rise to supersonic but turbulent jets. (paper)

High resolution data acquisition

Science.gov (United States)

Thornton, Glenn W.; Fuller, Kenneth R.

1993-01-01

A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

High resolution time integration for Sn radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2008-01-01

First order, second order and high resolution time discretization schemes are implemented and studied for the S n equations. The high resolution method employs a rate of convergence better than first order, but also suppresses artificial oscillations introduced by second order schemes in hyperbolic differential equations. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second order and high resolution converged to the same solution as the first order with better convergence rates. High resolution is more accurate than first order and matches or exceeds the second order method. (authors)

Structure of high-resolution NMR spectra

CERN Document Server

Corio, PL

2012-01-01

Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

Label-free cell-cycle analysis by high-throughput quantitative phase time-stretch imaging flow cytometry

Science.gov (United States)

Mok, Aaron T. Y.; Lee, Kelvin C. M.; Wong, Kenneth K. Y.; Tsia, Kevin K.

2018-02-01

Biophysical properties of cells could complement and correlate biochemical markers to characterize a multitude of cellular states. Changes in cell size, dry mass and subcellular morphology, for instance, are relevant to cell-cycle progression which is prevalently evaluated by DNA-targeted fluorescence measurements. Quantitative-phase microscopy (QPM) is among the effective biophysical phenotyping tools that can quantify cell sizes and sub-cellular dry mass density distribution of single cells at high spatial resolution. However, limited camera frame rate and thus imaging throughput makes QPM incompatible with high-throughput flow cytometry - a gold standard in multiparametric cell-based assay. Here we present a high-throughput approach for label-free analysis of cell cycle based on quantitative-phase time-stretch imaging flow cytometry at a throughput of > 10,000 cells/s. Our time-stretch QPM system enables sub-cellular resolution even at high speed, allowing us to extract a multitude (at least 24) of single-cell biophysical phenotypes (from both amplitude and phase images). Those phenotypes can be combined to track cell-cycle progression based on a t-distributed stochastic neighbor embedding (t-SNE) algorithm. Using multivariate analysis of variance (MANOVA) discriminant analysis, cell-cycle phases can also be predicted label-free with high accuracy at >90% in G1 and G2 phase, and >80% in S phase. We anticipate that high throughput label-free cell cycle characterization could open new approaches for large-scale single-cell analysis, bringing new mechanistic insights into complex biological processes including diseases pathogenesis.

High-resolution multi-slice PET

International Nuclear Information System (INIS)

Yasillo, N.J.; Chintu Chen; Ordonez, C.E.; Kapp, O.H.; Sosnowski, J.; Beck, R.N.

1992-01-01

This report evaluates the progress to test the feasibility and to initiate the design of a high resolution multi-slice PET system. The following specific areas were evaluated: detector development and testing; electronics configuration and design; mechanical design; and system simulation. The design and construction of a multiple-slice, high-resolution positron tomograph will provide substantial improvements in the accuracy and reproducibility of measurements of the distribution of activity concentrations in the brain. The range of functional brain research and our understanding of local brain function will be greatly extended when the development of this instrumentation is completed

High resolution NMR spectroscopy of synthetic polymers in bulk

International Nuclear Information System (INIS)

Komorski, R.A.

1986-01-01

The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

3D high spectral and spatial resolution imaging of ex vivo mouse brain

Energy Technology Data Exchange (ETDEWEB)

Foxley, Sean, E-mail: sean.foxley@ndcn.ox.ac.uk; Karczmar, Gregory S. [Department of Radiology, University of Chicago, Chicago, Illinois 60637 (United States); Domowicz, Miriam [Department of Pediatrics, University of Chicago, Chicago, Illinois 60637 (United States); Schwartz, Nancy [Department of Pediatrics, Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637 (United States)

2015-03-15

Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T{sub 2}{sup *}-weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T{sub 2}{sup *} and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm{sup 3} and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T{sub 2}{sup *}-weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in

High resolution integral holography using Fourier ptychographic approach.

Science.gov (United States)

Li, Zhaohui; Zhang, Jianqi; Wang, Xiaorui; Liu, Delian

2014-12-29

An innovative approach is proposed for calculating high resolution computer generated integral holograms by using the Fourier Ptychographic (FP) algorithm. The approach initializes a high resolution complex hologram with a random guess, and then stitches together low resolution multi-view images, synthesized from the elemental images captured by integral imaging (II), to recover the high resolution hologram through an iterative retrieval with FP constrains. This paper begins with an analysis of the principle of hologram synthesis from multi-projections, followed by an accurate determination of the constrains required in the Fourier ptychographic integral-holography (FPIH). Next, the procedure of the approach is described in detail. Finally, optical reconstructions are performed and the results are demonstrated. Theoretical analysis and experiments show that our proposed approach can reconstruct 3D scenes with high resolution.

Trigonometric parallaxes of high mass star forming regions: the structure and kinematics of the Milky Way

Energy Technology Data Exchange (ETDEWEB)

Reid, M. J.; Dame, T. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Menten, K. M.; Brunthaler, A.; Wu, Y.; Zhang, B.; Sanna, A.; Sato, M.; Choi, Y. K.; Immer, K. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Zheng, X. W. [Department of Astronomy, Nanjing University Nanjing 210093 (China); Xu, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Hachisuka, K. [Shanghai Astronomical Observatory, 80 Nandan Rd., Shanghai (China); Moscadelli, L. [Arcetri Observatory, Firenze (Italy); Rygl, K. L. J. [European Space Agency (ESA-ESTEC), Keplerlaan 1, P.O. Box 299, 2200 AG, Noordwijk (Netherlands); Bartkiewicz, A. [Centre for Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland)

2014-03-10

Over 100 trigonometric parallaxes and proper motions for masers associated with young, high-mass stars have been measured with the Bar and Spiral Structure Legacy Survey, a Very Long Baseline Array key science project, the European VLBI Network, and the Japanese VLBI Exploration of Radio Astrometry project. These measurements provide strong evidence for the existence of spiral arms in the Milky Way, accurately locating many arm segments and yielding spiral pitch angles ranging from about 7° to 20°. The widths of spiral arms increase with distance from the Galactic center. Fitting axially symmetric models of the Milky Way with the three-dimensional position and velocity information and conservative priors for the solar and average source peculiar motions, we estimate the distance to the Galactic center, R {sub 0}, to be 8.34 ± 0.16 kpc, a circular rotation speed at the Sun, Θ{sub 0}, to be 240 ± 8 km s{sup –1}, and a rotation curve that is nearly flat (i.e., a slope of –0.2 ± 0.4 km s{sup –1} kpc{sup –1}) between Galactocentric radii of ≈5 and 16 kpc. Assuming a 'universal' spiral galaxy form for the rotation curve, we estimate the thin disk scale length to be 2.44 ± 0.16 kpc. With this large data set, the parameters R {sub 0} and Θ{sub 0} are no longer highly correlated and are relatively insensitive to different forms of the rotation curve. If one adopts a theoretically motivated prior that high-mass star forming regions are in nearly circular Galactic orbits, we estimate a global solar motion component in the direction of Galactic rotation, V {sub ☉} = 14.6 ± 5.0 km s{sup –1}. While Θ{sub 0} and V {sub ☉} are significantly correlated, the sum of these parameters is well constrained, Θ{sub 0} + V {sub ☉} = 255.2 ± 5.1 km s{sup –1}, as is the angular speed of the Sun in its orbit about the Galactic center, (Θ{sub 0} + V {sub ☉})/R {sub 0} = 30.57 ± 0.43 km s{sup –1} kpc{sup –1}. These parameters improve the accuracy

ChelomEx: Isotope-assisted discovery of metal chelates in complex media using high-resolution LC-MS.

Science.gov (United States)

Baars, Oliver; Morel, François M M; Perlman, David H

2014-11-18

Chelating agents can control the speciation and reactivity of trace metals in biological, environmental, and laboratory-derived media. A large number of trace metals (including Fe, Cu, Zn, Hg, and others) show characteristic isotopic fingerprints that can be exploited for the discovery of known and unknown organic metal complexes and related chelating ligands in very complex sample matrices using high-resolution liquid chromatography mass spectrometry (LC-MS). However, there is currently no free open-source software available for this purpose. We present a novel software tool, ChelomEx, which identifies isotope pattern-matched chromatographic features associated with metal complexes along with free ligands and other related adducts in high-resolution LC-MS data. High sensitivity and exclusion of false positives are achieved by evaluation of the chromatographic coherence of the isotope pattern within chromatographic features, which we demonstrate through the analysis of bacterial culture media. A built-in graphical user interface and compound library aid in identification and efficient evaluation of results. ChelomEx is implemented in MatLab. The source code, binaries for MS Windows and MAC OS X as well as test LC-MS data are available for download at SourceForge ( http://sourceforge.net/projects/chelomex ).

High-spatial resolution and high-spectral resolution detector for use in the measurement of solar flare hard x rays

International Nuclear Information System (INIS)

Desai, U.D.; Orwig, L.E.

1988-01-01

In the areas of high spatial resolution, the evaluation of a hard X-ray detector with 65 micron spatial resolution for operation in the energy range from 30 to 400 keV is proposed. The basic detector is a thick large-area scintillator faceplate, composed of a matrix of high-density scintillating glass fibers, attached to a proximity type image intensifier tube with a resistive-anode digital readout system. Such a detector, combined with a coded-aperture mask, would be ideal for use as a modest-sized hard X-ray imaging instrument up to X-ray energies as high as several hundred keV. As an integral part of this study it was also proposed that several techniques be critically evaluated for X-ray image coding which could be used with this detector. In the area of high spectral resolution, it is proposed to evaluate two different types of detectors for use as X-ray spectrometers for solar flares: planar silicon detectors and high-purity germanium detectors (HPGe). Instruments utilizing these high-spatial-resolution detectors for hard X-ray imaging measurements from 30 to 400 keV and high-spectral-resolution detectors for measurements over a similar energy range would be ideally suited for making crucial solar flare observations during the upcoming maximum in the solar cycle

High resolution photoelectron spectroscopy

International Nuclear Information System (INIS)

Arko, A.J.

1988-01-01

Photoelectron Spectroscopy (PES) covers a very broad range of measurements, disciplines, and interests. As the next generation light source, the FEL will result in improvements over the undulator that are larger than the undulater improvements over bending magnets. The combination of high flux and high inherent resolution will result in several orders of magnitude gain in signal to noise over measurements using synchrotron-based undulators. The latter still require monochromators. Their resolution is invariably strongly energy-dependent so that in the regions of interest for many experiments (h upsilon > 100 eV) they will not have a resolving power much over 1000. In order to study some of the interesting phenomena in actinides (heavy fermions e.g.) one would need resolving powers of 10 4 to 10 5 . These values are only reachable with the FEL

High resolution x-ray lensless imaging by differential holographic encoding

Energy Technology Data Exchange (ETDEWEB)

Zhu, D.; Guizar-Sicairos, M.; Wu, B.; Scherz, A.; Acremann, Y.; Tylisczcak, T.; Fischer, P.; Friedenberger, N.; Ollefs, K.; Farle, M.; Fienup, J. R.; Stohr, J.

2009-11-02

X-ray free electron lasers (X-FEL{sub s}) will soon offer femtosecond pulses of laterally coherent x-rays with sufficient intensity to record single-shot coherent scattering patterns for nanoscale imaging. Pulse trains created by splitand-delay techniques even open the door for cinematography on unprecedented nanometer length and femtosecond time scales. A key to real space ultrafast motion pictures is fast and reliable inversion of the recorded reciprocal space scattering patterns. Here we for the first time demonstrate in the x-ray regime the power of a novel technique for lensless high resolution imaging, previously suggested by Guizar-Sicairos and Fienup termed holography with extended reference by autocorrelation linear differential operation, HERALD0. We have achieved superior resolution over conventional x-ray Fourier transform holography (FTH) without sacrifices in SNR or significant increase in algorithmic complexity. By combining images obtained from individual sharp features on an extended reference, we further show that the resolution can be even extended beyond the reference fabrication limits. Direct comparison to iterative phase retrieval image reconstruction and images recorded with stateof- the-art zone plate microscopes is presented. Our results demonstrate the power of HERALDO as a favorable candidate for robust inversion of single-shot coherent scattering patterns.

High-Resolution X-Ray Lensless Imaging by Differential Holographic Encoding

Energy Technology Data Exchange (ETDEWEB)

Zhu, Diling [Stanford Univ., CA (United States). Dept. of Applied Physics; SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Inst. for Material and Energy Science; Guizar-Sicairos, Manuel [Univ. of Rochester, NY (United States). Inst. of Optics; Wu, Benny [Stanford Univ., CA (United States). Dept. of Applied Physics; SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Inst. for Material and Energy Science; Scherz, Andreas [SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Inst. for Material and Energy Science; Acremann, Yves [SLAC National Accelerator Lab., Menlo Park, CA (United States). Photon Ultrafast Laser Science and Engineering Inst. (PULSE); Tyliszczak, Tolek [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Fischer, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Center for X-ray Optics; Friedenberger, Nina [Universitat Duisburg-Essen (Germany). Dept. of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE); Ollefs, Katharina [Universitat Duisburg-Essen (Germany). Dept. of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE); Farle, Michael [Universitat Duisburg-Essen (Germany). Dept. of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE); Fienup, James R. [Univ. of Rochester, NY (United States). Inst. of Optics; Stöhr, Joachim [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source (LCLS)

2010-07-01

X-ray free electron lasers (X-FELs) will soon offer femtosecond pulses of laterally coherent x-rays with sufficient intensity to record single-shot coherent scattering patterns for nanoscale imaging. Pulse trains created by split and- delay techniques even open the door for cinematography on unprecedented nanometer length and femtosecond time scales. A key to real space ultrafast motion pictures is fast and reliable inversion of the recorded reciprocal space scattering patterns. Here we for the first time demonstrate in the x-ray regime the power of a novel technique for lensless high resolution imaging, previously suggested by Guizar-Sicairos and Fienup termed holography with extended reference by autocorrelation linear differential operation, HERALD0. We have achieved superior resolution over conventional x-ray Fourier transform holography (FTH) without sacrifices in SNR or significant increase in algorithmic complexity. By combining images obtained from individual sharp features on an extended reference, we further show that the resolution can be even extended beyond the reference fabrication limits. Direct comparison to iterative phase retrieval image reconstruction and images recorded with state of-the-art zone plate microscopes is presented. Our results demonstrate the power of HERALDO as a favorable candidate for robust inversion of single-shot coherent scattering patterns.

Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals

Energy Technology Data Exchange (ETDEWEB)

Stoupin, Stanislav; Shvyd' ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey [Advanced Photon Source, Argonne National Laboratory, Illinois 60439 (United States)

2012-02-15

We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

Magnetic Particle Imaging for High Temporal Resolution Assessment of Aneurysm Hemodynamics.

Directory of Open Access Journals (Sweden)

Jan Sedlacik

Full Text Available The purpose of this work was to demonstrate the capability of magnetic particle imaging (MPI to assess the hemodynamics in a realistic 3D aneurysm model obtained by additive manufacturing. MPI was compared with magnetic resonance imaging (MRI and dynamic digital subtraction angiography (DSA.The aneurysm model was of saccular morphology (7 mm dome height, 5 mm cross-section, 3-4 mm neck, 3.5 mm parent artery diameter and connected to a peristaltic pump delivering a physiological flow (250 mL/min and pulsation rate (70/min. High-resolution (4 h long 4D phase contrast flow quantification (4D pc-fq MRI was used to directly assess the hemodynamics of the model. Dynamic MPI, MRI, and DSA were performed with contrast agent injections (3 mL volume in 3 s through a proximally placed catheter.4D pc-fq measurements showed distinct pulsatile flow velocities (20-80 cm/s as well as lower flow velocities and a vortex inside the aneurysm. All three dynamic methods (MPI, MRI, and DSA also showed a clear pulsation pattern as well as delayed contrast agent dynamics within the aneurysm, which is most likely caused by the vortex within the aneurysm. Due to the high temporal resolution of MPI and DSA, it was possible to track the contrast agent bolus through the model and to estimate the average flow velocity (about 60 cm/s, which is in accordance with the 4D pc-fq measurements.The ionizing radiation free, 4D high resolution MPI method is a very promising tool for imaging and characterization of hemodynamics in human. It carries the possibility of overcoming certain disadvantages of other modalities like considerably lower temporal resolution of dynamic MRI and limited 2D characteristics of DSA. Furthermore, additive manufacturing is the key for translating powerful pre-clinical techniques into the clinic.

High-resolution regional climate model evaluation using variable-resolution CESM over California

Science.gov (United States)

Huang, X.; Rhoades, A.; Ullrich, P. A.; Zarzycki, C. M.

2015-12-01

Understanding the effect of climate change at regional scales remains a topic of intensive research. Though computational constraints remain a problem, high horizontal resolution is needed to represent topographic forcing, which is a significant driver of local climate variability. Although regional climate models (RCMs) have traditionally been used at these scales, variable-resolution global climate models (VRGCMs) have recently arisen as an alternative for studying regional weather and climate allowing two-way interaction between these domains without the need for nudging. In this study, the recently developed variable-resolution option within the Community Earth System Model (CESM) is assessed for long-term regional climate modeling over California. Our variable-resolution simulations will focus on relatively high resolutions for climate assessment, namely 28km and 14km regional resolution, which are much more typical for dynamically downscaled studies. For comparison with the more widely used RCM method, the Weather Research and Forecasting (WRF) model will be used for simulations at 27km and 9km. All simulations use the AMIP (Atmospheric Model Intercomparison Project) protocols. The time period is from 1979-01-01 to 2005-12-31 (UTC), and year 1979 was discarded as spin up time. The mean climatology across California's diverse climate zones, including temperature and precipitation, is analyzed and contrasted with the Weather Research and Forcasting (WRF) model (as a traditional RCM), regional reanalysis, gridded observational datasets and uniform high-resolution CESM at 0.25 degree with the finite volume (FV) dynamical core. The results show that variable-resolution CESM is competitive in representing regional climatology on both annual and seasonal time scales. This assessment adds value to the use of VRGCMs for projecting climate change over the coming century and improve our understanding of both past and future regional climate related to fine

Section on High Resolution Optical Imaging (HROI)

Data.gov (United States)

Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

OGLE-2015-BLG-0196: GROUND-BASED GRAVITATIONAL MICROLENS PARALLAX CONFIRMED BY SPACE-BASED OBSERVATION

Energy Technology Data Exchange (ETDEWEB)

Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Soszyński, I.; Skowron, J.; Mróz, P.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Pawlak, M. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, A.; Zhu, Wei; Fausnaugh, M.; Gaudi, B. S. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Beichman, C. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Novati, S. Calchi [Dipartimento di Fisica “E. R. Caianiello,” Uńiversitá di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (Italy); Carey, S. [Spitzer Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Bryden, C. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Collaboration: OGLE Collaboration; Spitzer Microlensing Team; and others

2017-01-01

In this paper, we present an analysis of the binary gravitational microlensing event OGLE-2015-BLG-0196. The event lasted for almost a year, and the light curve exhibited significant deviations from the lensing model based on the rectilinear lens-source relative motion, enabling us to measure the microlens parallax. The ground-based microlens parallax is confirmed by the data obtained from space-based microlens observations using the Spitzer telescope. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined up to the twofold degeneracy, u {sub 0} < 0 and u {sub 0} > 0, solutions caused by the well-known “ecliptic” degeneracy. It is found that the binary lens is composed of two M dwarf stars with similar masses, M {sub 1} = 0.38 ± 0.04 M {sub ⊙} (0.50 ± 0.05 M {sub ⊙}) and M {sub 2} = 0.38 ± 0.04 M {sub ⊙} (0.55 ± 0.06 M {sub ⊙}), and the distance to the lens is D {sub L} = 2.77 ± 0.23 kpc (3.30 ± 0.29 kpc). Here the physical parameters outside and inside the parentheses are for the u {sub 0} < 0 and u {sub 0} > 0 solutions, respectively.

High angular resolution at LBT

Science.gov (United States)

Conrad, A.; Arcidiacono, C.; Bertero, M.; Boccacci, P.; Davies, A. G.; Defrere, D.; de Kleer, K.; De Pater, I.; Hinz, P.; Hofmann, K. H.; La Camera, A.; Leisenring, J.; Kürster, M.; Rathbun, J. A.; Schertl, D.; Skemer, A.; Skrutskie, M.; Spencer, J. R.; Veillet, C.; Weigelt, G.; Woodward, C. E.

2015-12-01

High angular resolution from ground-based observatories stands as a key technology for advancing planetary science. In the window between the angular resolution achievable with 8-10 meter class telescopes, and the 23-to-40 meter giants of the future, LBT provides a glimpse of what the next generation of instruments providing higher angular resolution will provide. We present first ever resolved images of an Io eruption site taken from the ground, images of Io's Loki Patera taken with Fizeau imaging at the 22.8 meter LBT [Conrad, et al., AJ, 2015]. We will also present preliminary analysis of two data sets acquired during the 2015 opposition: L-band fringes at Kurdalagon and an occultation of Loki and Pele by Europa (see figure). The light curves from this occultation will yield an order of magnitude improvement in spatial resolution along the path of ingress and egress. We will conclude by providing an overview of the overall benefit of recent and future advances in angular resolution for planetary science.

A method for generating high resolution satellite image time series

Science.gov (United States)

Guo, Tao

2014-10-01

There is an increasing demand for satellite remote sensing data with both high spatial and temporal resolution in many applications. But it still is a challenge to simultaneously improve spatial resolution and temporal frequency due to the technical limits of current satellite observation systems. To this end, much R&D efforts have been ongoing for years and lead to some successes roughly in two aspects, one includes super resolution, pan-sharpen etc. methods which can effectively enhance the spatial resolution and generate good visual effects, but hardly preserve spectral signatures and result in inadequate analytical value, on the other hand, time interpolation is a straight forward method to increase temporal frequency, however it increase little informative contents in fact. In this paper we presented a novel method to simulate high resolution time series data by combing low resolution time series data and a very small number of high resolution data only. Our method starts with a pair of high and low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and then projected onto the high resolution data plane and assigned to each high resolution pixel according to the predefined temporal change patterns of each type of ground objects. Finally the simulated high resolution data is generated. A preliminary experiment shows that our method can simulate a high resolution data with a reasonable accuracy. The contribution of our method is to enable timely monitoring of temporal changes through analysis of time sequence of low resolution images only, and usage of costly high resolution data can be reduces as much as possible, and it presents a highly effective way to build up an economically operational monitoring solution for agriculture, forest, land use investigation

Fabrication of thin TEM sample of ionic liquid for high-resolution ELNES measurements

Energy Technology Data Exchange (ETDEWEB)

Miyata, Tomohiro, E-mail: tomo-m@iis.u-tokyo.ac.jp; Mizoguchi, Teruyasu, E-mail: teru@iis.u-tokyo.ac.jp

2017-07-15

Investigation of the local structure, ionic and molecular behavior, and chemical reactions at high spatial resolutions in liquids has become increasingly important. Improvements in these areas help to develop efficient batteries and improve organic syntheses. Transmission electron microscopy (TEM) and scanning-TEM (STEM) have excellent spatial resolution, and the electron energy-loss near edge structure (ELNES) measured by the accompanied electron energy-loss spectroscopy (EELS) is effective to analyze the liquid local structure owing to reflecting the electronic density of states. In this study, we fabricate a liquid-layer-only sample with thickness of single to tens nanometers using an ionic liquid. Because the liquid film has a thickness much less than the inelastic mean free path (IMFP) of the electron beam, the fine structure of the C-K edge electron energy loss near edge structure (ELNES) can be measured with sufficient resolution to allow meaningful analysis. The ELNES spectrum from the thin liquid film has been interpreted using first principles ELNES calculations. - Highlights: • A fabrication method of thin liquid film samples for STEM-EELS observations is proposed. • The thickness of the fabricated thin liquid film is about 10 nm. • An ELNES is measured from the thin liquid with a high energy resolution. • The peaks of the ELNES are interpreted using first principles calculations.

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

Science.gov (United States)

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

2011-06-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99 m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional “straight-cut” (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera.

Science.gov (United States)

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G; Nagarkar, Vivek V

2011-06-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Resolution enhancement of low-quality videos using a high-resolution frame

Science.gov (United States)

Pham, Tuan Q.; van Vliet, Lucas J.; Schutte, Klamer

2006-01-01

This paper proposes an example-based Super-Resolution (SR) algorithm of compressed videos in the Discrete Cosine Transform (DCT) domain. Input to the system is a Low-Resolution (LR) compressed video together with a High-Resolution (HR) still image of similar content. Using a training set of corresponding LR-HR pairs of image patches from the HR still image, high-frequency details are transferred from the HR source to the LR video. The DCT-domain algorithm is much faster than example-based SR in spatial domain 6 because of a reduction in search dimensionality, which is a direct result of the compact and uncorrelated DCT representation. Fast searching techniques like tree-structure vector quantization 16 and coherence search1 are also key to the improved efficiency. Preliminary results on MJPEG sequence show promising result of the DCT-domain SR synthesis approach.

Ultrafast secondary emission x-ray imaging detectors

International Nuclear Information System (INIS)

Akkerman, A.; Gibrekhterman, A.; Majewski, S.

1991-07-01

Fast high accuracy, x-ray imaging at high photon flux can be achieved when coupling thin solid convertors to gaseous electron multipliers, operating at low gas pressures. Secondary electron emitted from the convertor foil are multiplied in several successive amplification elements. The obvious advantage of solid x-ray detectors, as compared to gaseous conversion, are the production of parallax-free images and the fast (subnanoseconds) response. These x-ray detectors have many potential applications in basic and applied research. Of particular interest is the possibility of an efficient and ultrafast high resolution imaging of transition radiation,with a reduced dE/dx background. We present experimental results on the operation of the secondary emission x-ray (SEX) detectors, their detection efficiency, localization and time resolution. The experimental work is accompanied by mathematical modelling and computer simulation of transition radiation detectors based on CsI transition radiation convertors. (author)

SPITZER AS A MICROLENS PARALLAX SATELLITE: MASS MEASUREMENT FOR THE OGLE-2014-BLG-0124L PLANET AND ITS HOST STAR

Energy Technology Data Exchange (ETDEWEB)

Udalski, A.; Skowron, J.; Kozłowski, S.; Poleski, R.; Pietrukowicz, P.; Pietrzyński, G.; Szymański, M. K.; Mróz, P.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Gould, A.; Zhu, W.; Pogge, R. W. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Carey, S. [Spitzer Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Han, C. [Department of Physics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Calchi Novati, S. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)

2015-02-01

We combine Spitzer and ground-based observations to measure the microlens parallax vector π{sub E}, and thus the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. The planet and star have masses of m ∼ 0.5 M {sub jup} and M ∼ 0.7 M {sub ☉} and are separated by a ∼ 3.1 AU in projection. The main source of uncertainty in all of these numbers (approximately 30%, 30%, and 20%) is the relatively poor measurement of the Einstein radius θ{sub E}, rather than uncertainty in π{sub E}, which is measured with 2.5% precision. This compares to 22% based on OGLE data alone, implying that the Spitzer data provide not only a substantial improvement in the precision of the π{sub E} measurement, but also the first independent test of a ground-based π{sub E} measurement.

High-Resolution Mass Spectrometers

Science.gov (United States)

Marshall, Alan G.; Hendrickson, Christopher L.

2008-07-01

Over the past decade, mass spectrometry has been revolutionized by access to instruments of increasingly high mass-resolving power. For small molecules up to ˜400 Da (e.g., drugs, metabolites, and various natural organic mixtures ranging from foods to petroleum), it is possible to determine elemental compositions (CcHhNnOoSsPp…) of thousands of chemical components simultaneously from accurate mass measurements (the same can be done up to 1000 Da if additional information is included). At higher mass, it becomes possible to identify proteins (including posttranslational modifications) from proteolytic peptides, as well as lipids, glycoconjugates, and other biological components. At even higher mass (˜100,000 Da or higher), it is possible to characterize posttranslational modifications of intact proteins and to map the binding surfaces of large biomolecule complexes. Here we review the principles and techniques of the highest-resolution analytical mass spectrometers (time-of-flight and Fourier transform ion cyclotron resonance and orbitrap mass analyzers) and describe some representative high-resolution applications.

USGS High Resolution Orthoimagery Collection - Historical - National Geospatial Data Asset (NGDA) High Resolution Orthoimagery

Data.gov (United States)

U.S. Geological Survey, Department of the Interior — USGS high resolution orthorectified images from The National Map combine the image characteristics of an aerial photograph with the geometric qualities of a map. An...

Diamond x-ray optics: Transparent, resilient, high-resolution, and wavefront preserving

International Nuclear Information System (INIS)

Shvyd’ko, Yuri; Blank, Vladimir; Terentyev, Sergey

2017-01-01

Diamond features a unique combination of outstanding physical properties perfect for numerous x-ray optics applications, where traditional materials such as silicon fail to perform. In the last two decades, impressive progress has been achieved in synthesizing diamond with high crystalline perfection, in manufacturing efficient, resilient, high-resolution, wavefront-preserving diamond optical components, and in implementing them in cutting-edge x-ray instruments. Diamond optics are essential for tailoring x-rays to the most challenging needs of x-ray research. Furthermore, they are becoming vital for the generation of fully coherent hard x-rays by seeded x-ray free-electron lasers. In this article, we review progress in manufacturing flawless diamond crystal components and their applications in diverse x-ray optical devices, such as x-ray monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, bent-crystal spectrographs, and windows.

High throughput screening of ligand binding to macromolecules using high resolution powder diffraction

Science.gov (United States)

Von Dreele, Robert B.; D'Amico, Kevin

2006-10-31

A process is provided for the high throughput screening of binding of ligands to macromolecules using high resolution powder diffraction data including producing a first sample slurry of a selected polycrystalline macromolecule material and a solvent, producing a second sample slurry of a selected polycrystalline macromolecule material, one or more ligands and the solvent, obtaining a high resolution powder diffraction pattern on each of said first sample slurry and the second sample slurry, and, comparing the high resolution powder diffraction pattern of the first sample slurry and the high resolution powder diffraction pattern of the second sample slurry whereby a difference in the high resolution powder diffraction patterns of the first sample slurry and the second sample slurry provides a positive indication for the formation of a complex between the selected polycrystalline macromolecule material and at least one of the one or more ligands.

Design and performance of a high resolution, low latency stripline beam position monitor system

Science.gov (United States)

Apsimon, R. J.; Bett, D. R.; Blaskovic Kraljevic, N.; Burrows, P. N.; Christian, G. B.; Clarke, C. I.; Constance, B. D.; Dabiri Khah, H.; Davis, M. R.; Perry, C.; Resta López, J.; Swinson, C. J.

2015-03-01

A high-resolution, low-latency beam position monitor (BPM) system has been developed for use in particle accelerators and beam lines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system was tested with electron beams in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. It consists of three stripline BPMs instrumented with analogue signal-processing electronics and a custom digitizer for logging the data. The design of the analogue processor units is presented in detail, along with measurements of the system performance. The processor latency is 15.6 ±0.1 ns . A single-pass beam position resolution of 291 ±10 nm has been achieved, using a beam with a bunch charge of approximately 1 nC.

Texton-based super-resolution for achieving high spatiotemporal resolution in hybrid camera system

Science.gov (United States)

Kamimura, Kenji; Tsumura, Norimichi; Nakaguchi, Toshiya; Miyake, Yoichi

2010-05-01

Many super-resolution methods have been proposed to enhance the spatial resolution of images by using iteration and multiple input images. In a previous paper, we proposed the example-based super-resolution method to enhance an image through pixel-based texton substitution to reduce the computational cost. In this method, however, we only considered the enhancement of a texture image. In this study, we modified this texton substitution method for a hybrid camera to reduce the required bandwidth of a high-resolution video camera. We applied our algorithm to pairs of high- and low-spatiotemporal-resolution videos, which were synthesized to simulate a hybrid camera. The result showed that the fine detail of the low-resolution video can be reproduced compared with bicubic interpolation and the required bandwidth could be reduced to about 1/5 in a video camera. It was also shown that the peak signal-to-noise ratios (PSNRs) of the images improved by about 6 dB in a trained frame and by 1.0-1.5 dB in a test frame, as determined by comparison with the processed image using bicubic interpolation, and the average PSNRs were higher than those obtained by the well-known Freeman’s patch-based super-resolution method. Compared with that of the Freeman’s patch-based super-resolution method, the computational time of our method was reduced to almost 1/10.

Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers

Energy Technology Data Exchange (ETDEWEB)

Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder

2012-07-01

The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.

Tycho- Gaia Astrometric Solution Parallaxes and Proper Motions for Five Galactic Globular Clusters

Energy Technology Data Exchange (ETDEWEB)

Watkins, Laura L.; Van der Marel, Roeland P., E-mail: lwatkins@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD 21218 (United States)

2017-04-20

We present a pilot study of Galactic globular cluster (GC) proper motion (PM) determinations using Gaia data. We search for GC stars in the Tycho- Gaia Astrometric Solution (TGAS) catalog from Gaia Data Release 1 (DR1), and identify five members of NGC 104 (47 Tucanae), one member of NGC 5272 (M3), five members of NGC 6121 (M4), seven members of NGC 6397, and two members of NGC 6656 (M22). By taking a weighted average of member stars, fully accounting for the correlations between parameters, we estimate the parallax (and, hence, distance) and PM of the GCs. This provides a homogeneous PM study of multiple GCs based on an astrometric catalog with small and well-controlled systematic errors and yields random PM errors similar to existing measurements. Detailed comparison to the available Hubble Space Telescope ( HST ) measurements generally shows excellent agreement, validating the astrometric quality of both TGAS and HST . By contrast, comparison to ground-based measurements shows that some of those must have systematic errors exceeding the random errors. Our parallax estimates have uncertainties an order of magnitude larger than previous studies, but nevertheless imply distances consistent with previous estimates. By combining our PM measurements with literature positions, distances, and radial velocities, we measure Galactocentric space motions for the clusters and find that these also agree well with previous analyses. Our analysis provides a framework for determining more accurate distances and PMs of Galactic GCs using future Gaia data releases. This will provide crucial constraints on the near end of the cosmic distance ladder and provide accurate GC orbital histories.

Immersion Gratings for Infrared High-resolution Spectroscopy

Science.gov (United States)

Sarugaku, Yuki; Ikeda, Yuji; Kobayashi, Naoto; Kaji, Sayumi; Sukegawa, Takashi; Sugiyama, Shigeru; Nakagawa, Takao; Arasaki, Takayuki; Kondo, Sohei; Nakanishi, Kenshi; Yasui, Chikako; Kawakita, Hideyo

2016-10-01

High-resolution spectroscopy in the infrared wavelength range is essential for observations of minor isotopologues, such as HDO for water, and prebiotic organic molecules like hydrocarbons/P-bearing molecules because numerous vibrational molecular bands (including non-polar molecules) are located in this wavelength range. High spectral resolution enables us to detect weak lines without spectral line confusion. This technique has been widely used in planetary sciences, e.g., cometary coma (H2O, CO, and organic molecules), the martian atmosphere (CH4, CO2, H2O and HDO), and the upper atmosphere of gas giants (H3+ and organic molecules such as C2H6). Spectrographs with higher resolution (and higher sensitivity) still have a potential to provide a plenty of findings. However, because the size of spectrographs scales with the spectral resolution, it is difficult to realize it.Immersion grating (IG), which is a diffraction grating wherein the diffraction surface is immersed in a material with a high refractive index (n > 2), provides n times higher spectral resolution compared to a reflective grating of the same size. Because IG reduces the size of spectrograph to 1/n compared to the spectrograph with the same spectral resolution using a conventional reflective grating, it is widely acknowledged as a key optical device to realize compact spectrographs with high spectral resolution.Recently, we succeeded in fabricating a CdZnTe immersion grating with the theoretically predicted diffraction efficiency by machining process using an ultrahigh-precision five-axis processing machine developed by Canon Inc. Using the same technique, we completed a practical germanium (Ge) immersion grating with both a reflection coating on the grating surface and the an AR coating on the entrance surface. It is noteworthy that the wide wavelength range from 2 to 20 um can be covered by the two immersion gratings.In this paper, we present the performances and the applications of the immersion

Fabrication and characterization of free-standing, high-line-density transmission gratings for the vacuum UV to soft X-ray range

NARCIS (Netherlands)

Goh, S.J.; Bastiaens, Hubertus M.J.; Vratzov, B.; Huang, Qiushi; Bijkerk, Frederik; Boller, Klaus J.

2015-01-01

We present state-of-the-art high resolution transmission gratings, applicable for spectroscopy in the vacuum ultraviolet (VUV) and the soft X-ray (SRX) wavelength range, fabricated with a novel process using ultraviolet based nano imprint lithography (UV-NIL). Free-standing, high-line-density

High resolution tomographic instrument development

International Nuclear Information System (INIS)

1992-01-01

Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational

High resolution tomographic instrument development

Energy Technology Data Exchange (ETDEWEB)

1992-08-01

Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

High resolution tomographic instrument development

Energy Technology Data Exchange (ETDEWEB)

1992-01-01

Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

High-resolution boundary conditions of an old ice target near Dome C, Antarctica

Science.gov (United States)

Young, Duncan A.; Roberts, Jason L.; Ritz, Catherine; Frezzotti, Massimo; Quartini, Enrica; Cavitte, Marie G. P.; Tozer, Carly R.; Steinhage, Daniel; Urbini, Stefano; Corr, Hugh F. J.; van Ommen, Tas; Blankenship, Donald D.

2017-08-01

A high-resolution (1 km line spacing) aerogeophysical survey was conducted over a region near the East Antarctic Ice Sheet's Dome C that may hold a 1.5 Myr climate record. We combined new ice thickness data derived from an airborne coherent radar sounder with unpublished data that was in part unavailable for earlier compilations, and we were able to remove older data with high positional uncertainties. We generated a revised high-resolution digital elevation model (DEM) to investigate the potential for an old ice record in this region, and used laser altimetry to confirm a Cryosat-2 derived DEM for inferring the glaciological state of the candidate area. By measuring the specularity content of the bed, we were able to find an additional 50 subglacial lakes near the candidate site, and by Doppler focusing the radar data, we were able to map out the roughness of the bed at length scales of hundreds of meters. We find that the primary candidate region contains elevated rough topography interspersed with scattered subglacial lakes and some regions of smoother bed. Free subglacial water appears to be restricted from bed overlain by ice thicknesses of less than 3000 m. A site near the ice divide was selected for further investigation. The high resolution of this ice thickness data set also allows us to explore the nature of ice thickness uncertainties in the context of radar geometry and processing.

High resolution Neutron and Synchrotron Powder Diffraction

International Nuclear Information System (INIS)

Hewat, A.W.

1986-01-01

The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

High resolution (transformers.

Science.gov (United States)

Garcia-Souto, Jose A; Lamela-Rivera, Horacio

2006-10-16

A novel fiber-optic interferometric sensor is presented for vibrations measurements and analysis. In this approach, it is shown applied to the vibrations of electrical structures within power transformers. A main feature of the sensor is that an unambiguous optical phase measurement is performed using the direct detection of the interferometer output, without external modulation, for a more compact and stable implementation. High resolution of the interferometric measurement is obtained with this technique (transformers are also highlighted.

High-resolution wavefront control of high-power laser systems

International Nuclear Information System (INIS)

Brase, J.; Brown, C.; Carrano, C.; Kartz, M.; Olivier, S.; Pennington, D.; Silva, D.

1999-01-01

Nearly every new large-scale laser system application at LLNL has requirements for beam control which exceed the current level of available technology. For applications such as inertial confinement fusion, laser isotope separation, laser machining, and laser the ability to transport significant power to a target while maintaining good beam quality is critical. There are many ways that laser wavefront quality can be degraded. Thermal effects due to the interaction of high-power laser or pump light with the internal optical components or with the ambient gas are common causes of wavefront degradation. For many years, adaptive optics based on thing deformable glass mirrors with piezoelectric or electrostrictive actuators have be used to remove the low-order wavefront errors from high-power laser systems. These adaptive optics systems have successfully improved laser beam quality, but have also generally revealed additional high-spatial-frequency errors, both because the low-order errors have been reduced and because deformable mirrors have often introduced some high-spatial-frequency components due to manufacturing errors. Many current and emerging laser applications fall into the high-resolution category where there is an increased need for the correction of high spatial frequency aberrations which requires correctors with thousands of degrees of freedom. The largest Deformable Mirrors currently available have less than one thousand degrees of freedom at a cost of approximately $1M. A deformable mirror capable of meeting these high spatial resolution requirements would be cost prohibitive. Therefore a new approach using a different wavefront control technology is needed. One new wavefront control approach is the use of liquid-crystal (LC) spatial light modulator (SLM) technology for the controlling the phase of linearly polarized light. Current LC SLM technology provides high-spatial-resolution wavefront control, with hundreds of thousands of degrees of freedom, more

Objective-lens-free Fiber-based Position Detection with Nanometer Resolution in a Fiber Optical Trapping System.

Science.gov (United States)

Ti, Chaoyang; Ho-Thanh, Minh-Tri; Wen, Qi; Liu, Yuxiang

2017-10-13

Position detection with high accuracy is crucial for force calibration of optical trapping systems. Most existing position detection methods require high-numerical-aperture objective lenses, which are bulky, expensive, and difficult to miniaturize. Here, we report an affordable objective-lens-free, fiber-based position detection scheme with 2 nm spatial resolution and 150 MHz bandwidth. This fiber based detection mechanism enables simultaneous trapping and force measurements in a compact fiber optical tweezers system. In addition, we achieved more reliable signal acquisition with less distortion compared with objective based position detection methods, thanks to the light guiding in optical fibers and small distance between the fiber tips and trapped particle. As a demonstration of the fiber based detection, we used the fiber optical tweezers to apply a force on a cell membrane and simultaneously measure the cellular response.

High resolution optical DNA mapping

Science.gov (United States)

Baday, Murat

Many types of diseases including cancer and autism are associated with copy-number variations in the genome. Most of these variations could not be identified with existing sequencing and optical DNA mapping methods. We have developed Multi-color Super-resolution technique, with potential for high throughput and low cost, which can allow us to recognize more of these variations. Our technique has made 10--fold improvement in the resolution of optical DNA mapping. Using a 180 kb BAC clone as a model system, we resolved dense patterns from 108 fluorescent labels of two different colors representing two different sequence-motifs. Overall, a detailed DNA map with 100 bp resolution was achieved, which has the potential to reveal detailed information about genetic variance and to facilitate medical diagnosis of genetic disease.

The influence of photon depth of interaction and non-collinear spread of annihilation photons on PET image spatial resolution

International Nuclear Information System (INIS)

Sanchez-Crespo, Alejandro; Larsson, Stig A.

2006-01-01

The quality of PET imaging is impaired by parallax errors. These errors produce misalignment between the projected location of the true origin of the annihilation event and the line of response determined by the coincidence detection system. Parallax errors are due to the varying depths of photon interaction (DOI) within the scintillator and the non-collinear (NC) emission of the annihilation photons. The aim of this work was to address the problems associated with the DOI and the NC spread of annihilation photons and to develop a quantitative model to assess their impact on image spatial resolution losses for various commonly used scintillators and PET geometries. A theoretical model based on Monte Carlo simulations was developed to assess the relative influence of DOI and the NC spread of annihilation photons on PET spatial resolution for various scintillator materials (BGO, LSO, LuAP, GSO, NaI) and PET geometries. The results demonstrate good agreement between simulated, experimental and published overall spatial resolution for some commercial systems, with maximum differences around 1 mm in both 2D and 3D mode. The DOI introduces an impairment of non-stationary spatial resolution along the radial direction, which can be very severe at peripheral positions. As an example, the radial spatial resolution loss due to DOI increased from 1.3 mm at the centre to 6.7 mm at 20 cm from the centre of a BGO camera with a 412-mm radius in 2D mode. Including the NC, the corresponding losses were 3.0 mm at the centre and 7.3 mm 20 cm from the centre. Without a DOI detection technique, it seems difficult to improve PET spatial resolution and increase sensitivity by reducing the detector ring radius or by extending the detector in the axial direction. Much effort is expended on the design and configuration of smaller detector elements but more effort should be devoted to the DOI complexity. (orig.)

High-Resolution Electronics: Spontaneous Patterning of High-Resolution Electronics via Parallel Vacuum Ultraviolet (Adv. Mater. 31/2016).

Science.gov (United States)

Liu, Xuying; Kanehara, Masayuki; Liu, Chuan; Sakamoto, Kenji; Yasuda, Takeshi; Takeya, Jun; Minari, Takeo

2016-08-01

On page 6568, T. Minari and co-workers describe spontaneous patterning based on the parallel vacuum ultraviolet (PVUV) technique, enabling the homogeneous integration of complex, high-resolution electronic circuits, even on large-scale, flexible, transparent substrates. Irradiation of PVUV to the hydrophobic polymer surface precisely renders the selected surface into highly wettable regions with sharply defined boundaries, which spontaneously guides a metal nanoparticle ink into a series of circuit lines and gaps with the widths down to a resolution of 1 μm. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High resolution UV spectroscopy and laser-focused nanofabrication

NARCIS (Netherlands)

Myszkiewicz, G.

2005-01-01

This thesis combines two at first glance different techniques: High Resolution Laser Induced Fluorescence Spectroscopy (LIF) of small aromatic molecules and Laser Focusing of atoms for Nanofabrication. The thesis starts with the introduction to the high resolution LIF technique of small aromatic

High-resolution spectrometer at PEP

International Nuclear Information System (INIS)

Weiss, J.M.; HRS Collaboration.

1982-01-01

A description is presented of the High Resolution Spectrometer experiment (PEP-12) now running at PEP. The advanced capabilities of the detector are demonstrated with first physics results expected in the coming months

High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy

International Nuclear Information System (INIS)

Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R.; Murshudov, Garib N.; Short, Judith M.; Scheres, Sjors H.W.; Henderson, Richard

2013-01-01

unbiased FSC from the two curves, even when a substantial amount of overfitting is present. The approach is software independent. The user is therefore completely free to use any established method or novel combination of methods, provided the HR-noise test is carried out in parallel. Applying this procedure to cryoEM images of beta-galactosidase shows how overfitting varies greatly depending on the procedure, but in the best case shows no overfitting and a resolution of ∼6 Å. (382 words) - Highlights: • A new method to validate 3D cryoEM maps of biological structures is described. • High-resolution noise substitution is a tool to measure the amount of overfitting of noise in single particle cryoEM. • A reliable, unbiased resolution estimation can be obtained even when some overfitting is present. • Structure of beta-galactosidase at ∼6 Å resolution is determined by cryoEM

High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy

Energy Technology Data Exchange (ETDEWEB)

Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R.; Murshudov, Garib N.; Short, Judith M.; Scheres, Sjors H.W.; Henderson, Richard, E-mail: rh15@mrc-lmb.cam.ac.uk

2013-12-15

unbiased FSC from the two curves, even when a substantial amount of overfitting is present. The approach is software independent. The user is therefore completely free to use any established method or novel combination of methods, provided the HR-noise test is carried out in parallel. Applying this procedure to cryoEM images of beta-galactosidase shows how overfitting varies greatly depending on the procedure, but in the best case shows no overfitting and a resolution of ∼6 Å. (382 words) - Highlights: • A new method to validate 3D cryoEM maps of biological structures is described. • High-resolution noise substitution is a tool to measure the amount of overfitting of noise in single particle cryoEM. • A reliable, unbiased resolution estimation can be obtained even when some overfitting is present. • Structure of beta-galactosidase at ∼6 Å resolution is determined by cryoEM.

Kinetic energy spectra, vertical resolution and dissipation in high-resolution atmospheric simulations.

Science.gov (United States)

Skamarock, W. C.

2017-12-01

We have performed week-long full-physics simulations with the MPAS global model at 15 km cell spacing using vertical mesh spacings of 800, 400, 200 and 100 meters in the mid-troposphere through the mid-stratosphere. We find that the horizontal kinetic energy spectra in the upper troposphere and stratosphere does not converge with increasing vertical resolution until we reach 200 meter level spacing. Examination of the solutions indicates that significant inertia-gravity waves are not vertically resolved at the lower vertical resolutions. Diagnostics from the simulations indicate that the primary kinetic energy dissipation results from the vertical mixing within the PBL parameterization and from the gravity-wave drag parameterization, with smaller but significant contributions from damping in the vertical transport scheme and from the horizontal filters in the dynamical core. Most of the kinetic energy dissipation in the free atmosphere occurs within breaking mid-latitude baroclinic waves. We will briefly review these results and their implications for atmospheric model configuration and for atmospheric dynamics, specifically that related to the dynamics associated with the mesoscale kinetic energy spectrum.

Development of a 1 GS/s high-resolution transient recorder

CERN Document Server

Bartknecht, S; Herrmann, F; Königsmann, K; Lauser, L; Schill, C; Schopferer, S; Wollny, H

2009-01-01

With present-day detectors in high energy physics one is often faced with short analog pulses of a few nanoseconds length which may cover large dynamic ranges. In many experiments both amplitude and timing information have to be measured with high accuracy. Additionally, the data rate per readout channel can reach several MHz, which makes high demands on the separation of pile-up pulses. For such applications we have built the GANDALF transient recorder with a resolution of 12bit@1GS/s and an analog bandwidth of 500 MHz. Signals are digitized and processed by fast algorithms to extract pulse arrival times and amplitudes in real-time and to generate experiment trigger signals. With up to 16 analog channels, deep memories and a high data rate interface, this 6U-VME64x/VXS module is not only a dead-time free digitization unit but also has huge numerical capabilities provided by the implementation of a Virtex5-SXT FPGA. Fast algorithms implemented in the FPGA may be used to disentangle possible pile-up pulses and...

Requirements on high resolution detectors

Energy Technology Data Exchange (ETDEWEB)

Koch, A. [European Synchrotron Radiation Facility, Grenoble (France)

1997-02-01

For a number of microtomography applications X-ray detectors with a spatial resolution of 1 {mu}m are required. This high spatial resolution will influence and degrade other parameters of secondary importance like detective quantum efficiency (DQE), dynamic range, linearity and frame rate. This note summarizes the most important arguments, for and against those detector systems which could be considered. This article discusses the mutual dependencies between the various figures which characterize a detector, and tries to give some ideas on how to proceed in order to improve present technology.

High-resolution clean-sc

NARCIS (Netherlands)

Sijtsma, P.; Snellen, M.

2016-01-01

In this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak,

A constructive approach to minimal free resolutions of path ideals of trees

Directory of Open Access Journals (Sweden)

Rachelle R. Bouchat

2017-01-01

Full Text Available For a rooted tree $\\Gamma$, we consider path ideals of $\\Gamma$, which are ideals that are generated by all directed paths of a fixed length in $\\Gamma$. In this paper, we provide a combinatorial description of the minimal free resolution of these path ideals. In particular, we provide a class of subforests of $\\Gamma$ that are in one-to-one correspondence with the multi-graded Betti numbers of the path ideal as well as providing a method for determining the projective dimension and the Castelnuovo-Mumford regularity of a given path ideal.

High-resolution MR imaging of the knee at 3 T

Energy Technology Data Exchange (ETDEWEB)

Niitsu, M.; Nakai, T.; Ikeda, K.; Tang, G.Y.; Yoshioka, H.; Itai, Y. [Tsukuba Univ., Ibaraki (Japan). Dept. of Radiology

2000-07-01

In order to examine the practical feasibility of using a 3.0-T MR unit to obtain high-quality, high-resolution images of the knee joint, one human cadaveric and 5 porcine knees were imaged with the 3.0-T unit. Sets of T1-weighted spin echo images were obtained with in-plane resolution of 0.195x0.39 mm and an acquisition time of approximately 5 min. Two porcine knees were also imaged with the 1.0-T unit with an identical imaging protocol and the signal-to-noise (S/N) ratios were measured on images at 3 T and 1 T. The 3-T MR system provided detailed delineation of the knees. Deep layers of the medial collateral ligament and associated fine fibers beneath the medial and lateral collateral ligament were demarcated. We observed precise demonstration of the tibial attachment of the anterior cruciate ligament, irregularity of the meniscal free edge, and conjoint tendon formation together with the lateral collateral ligament and the biceps femoris tendon. Compared to the 1-T unit, the S/N ratio with the 3-T unit was increased by a factor of 1.39 to 1.72. Due to the potential advantage of obtaining detailed images, the 3-T MR system suggests a practical utility for fine demonstration of the knee morphology.

High-resolution MR imaging of the knee at 3 T

International Nuclear Information System (INIS)

Niitsu, M.; Nakai, T.; Ikeda, K.; Tang, G.Y.; Yoshioka, H.; Itai, Y.

2000-01-01

In order to examine the practical feasibility of using a 3.0-T MR unit to obtain high-quality, high-resolution images of the knee joint, one human cadaveric and 5 porcine knees were imaged with the 3.0-T unit. Sets of T1-weighted spin echo images were obtained with in-plane resolution of 0.195x0.39 mm and an acquisition time of approximately 5 min. Two porcine knees were also imaged with the 1.0-T unit with an identical imaging protocol and the signal-to-noise (S/N) ratios were measured on images at 3 T and 1 T. The 3-T MR system provided detailed delineation of the knees. Deep layers of the medial collateral ligament and associated fine fibers beneath the medial and lateral collateral ligament were demarcated. We observed precise demonstration of the tibial attachment of the anterior cruciate ligament, irregularity of the meniscal free edge, and conjoint tendon formation together with the lateral collateral ligament and the biceps femoris tendon. Compared to the 1-T unit, the S/N ratio with the 3-T unit was increased by a factor of 1.39 to 1.72. Due to the potential advantage of obtaining detailed images, the 3-T MR system suggests a practical utility for fine demonstration of the knee morphology

Full-parallax 3D display from stereo-hybrid 3D camera system

Science.gov (United States)

Hong, Seokmin; Ansari, Amir; Saavedra, Genaro; Martinez-Corral, Manuel

2018-04-01

In this paper, we propose an innovative approach for the production of the microimages ready to display onto an integral-imaging monitor. Our main contribution is using a stereo-hybrid 3D camera system, which is used for picking up a 3D data pair and composing a denser point cloud. However, there is an intrinsic difficulty in the fact that hybrid sensors have dissimilarities and therefore should be equalized. Handled data facilitate to generating an integral image after projecting computationally the information through a virtual pinhole array. We illustrate this procedure with some imaging experiments that provide microimages with enhanced quality. After projection of such microimages onto the integral-imaging monitor, 3D images are produced with great parallax and viewing angle.

IMPROVING VERTICAL AND LATERAL RESOLUTION BY STRETCH-FREE, HORIZON-ORIENTED IMAGING

Directory of Open Access Journals (Sweden)

Pérez Gabriel

2006-12-01

Full Text Available The pre-stack Kirchhoff migration is implemented for delivering wavelet stretch-free imaged data, if the migration is (ideally limited to the wavelet corresponding to a target horizon. Avoiding wavelet stretch provides long-offset imaged data, far beyond what is reached in conventional migration and results in images from the target with improved vertical and lateral resolution and angular illumination. Increasing the range of imaged offsets also increases the sensitivity to event-crossing, velocity errors and anisotropy. These issues must be addressed to fully achieve the greatest potential of this technique. These ideas are further illustrated with a land survey seismic data application in Texas, U.S.

Design and performance of a high resolution, low latency stripline beam position monitor system

Directory of Open Access Journals (Sweden)

R. J. Apsimon

2015-03-01

Full Text Available A high-resolution, low-latency beam position monitor (BPM system has been developed for use in particle accelerators and beam lines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system was tested with electron beams in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK in Japan. It consists of three stripline BPMs instrumented with analogue signal-processing electronics and a custom digitizer for logging the data. The design of the analogue processor units is presented in detail, along with measurements of the system performance. The processor latency is 15.6±0.1  ns. A single-pass beam position resolution of 291±10  nm has been achieved, using a beam with a bunch charge of approximately 1 nC.

High Resolution Robust GPS-free Localization for Wireless Sensor Networks and its Applications

KAUST Repository

Mirza, Mohammed

2011-12-12

In this thesis we investigate the problem of robustness and scalability w.r.t. estimating the position of randomly deployed motes/nodes of a Wireless Sensor Network (WSN) without the help of Global Positioning System (GPS) devices. We propose a few applications of range independent localization algorithms that allow the sensors to actively determine their location with high resolution without increasing the complexity of the hardware or any additional device setup. In our first application we try to present a localized and centralized cooperative spectrum sensing using RF sensor networks. This scheme collaboratively sense the spectrum and localize the whole network efficiently and with less difficulty. In second application we try to focus on how efficiently we can localize the nodes, to detect underwater threats, without the use of beacons. In third application we try to focus on 3-Dimensional localization for LTE systems. Our performance evaluation shows that these schemes lead to a significant improvement in localization accuracy compared to the state-of-art range independent localization schemes, without requiring GPS support.

Gamma-ray spectrometer system with high efficiency and high resolution

International Nuclear Information System (INIS)

Moss, C.E.; Bernard, W.; Dowdy, E.J.; Garcia, C.; Lucas, M.C.; Pratt, J.C.

1983-01-01

Our gamma-ray spectrometer system, designed for field use, offers high efficiency and high resolution for safeguards applications. The system consists of three 40% high-purity germanium detectors and a LeCroy 3500 data acquisition system that calculates a composite spectrum for the three detectors. The LeCroy 3500 mainframe can be operated remotely from the detector array with control exercised through modems and the telephone system. System performance with a mixed source of 125 Sb, 154 Eu, and 155 Eu confirms the expected efficiency of 120% with the overall resolution showing little degradation over that of the worst detector

Whole grain gluten-free egg-free high protein pasta

Science.gov (United States)

The USDA food guide recommends that at least ½ of all the grains eaten should be whole grains. The FDA allows food Health Claim labels for food containing 51% whole gains and 11 g of dietary fiber. This is the only report demonstrating innovative whole grain, high protein, gluten-free, egg-free past...

High resolution metric imaging payload

Science.gov (United States)

Delclaud, Y.

2017-11-01

Alcatel Space Industries has become Europe's leader in the field of high and very high resolution optical payloads, in the frame work of earth observation system able to provide military government with metric images from space. This leadership allowed ALCATEL to propose for the export market, within a French collaboration frame, a complete space based system for metric observation.

High-resolution X-ray diffraction studies of multilayers

DEFF Research Database (Denmark)

Christensen, Finn Erland; Hornstrup, Allan; Schnopper, H. W.

1988-01-01

High-resolution X-ray diffraction studies of the perfection of state-of-the-art multilayers are presented. Data were obtained using a triple-axis perfect-crystal X-ray diffractometer. Measurements reveal large-scale figure errors in the substrate. A high-resolution triple-axis set up is required...

Scalable Algorithms for Large High-Resolution Terrain Data

DEFF Research Database (Denmark)

Mølhave, Thomas; Agarwal, Pankaj K.; Arge, Lars Allan

2010-01-01

In this paper we demonstrate that the technology required to perform typical GIS computations on very large high-resolution terrain models has matured enough to be ready for use by practitioners. We also demonstrate the impact that high-resolution data has on common problems. To our knowledge, so...

High resolution NMR imaging using a high field yokeless permanent magnet.

Science.gov (United States)

Kose, Katsumi; Haishi, Tomoyuki

2011-01-01

We measured the homogeneity and stability of the magnetic field of a high field (about 1.04 tesla) yokeless permanent magnet with 40-mm gap for high resolution nuclear magnetic resonance (NMR) imaging. Homogeneity was evaluated using a 3-dimensional (3D) lattice phantom and 3D spin-echo imaging sequences. In the central sphere (20-mm diameter), peak-to-peak magnetic field inhomogeneity was about 60 ppm, and the root-mean-square was 8 ppm. We measured room temperature, magnet temperature, and NMR frequency of the magnet simultaneously every minute for about 68 hours with and without the thermal insulator of the magnet. A simple mathematical model described the magnet's thermal property. Based on magnet performance, we performed high resolution (up to [20 µm](2)) imaging with internal NMR lock sequences of several biological samples. Our results demonstrated the usefulness of the high field small yokeless permanent magnet for high resolution NMR imaging.

High resolution NMR imaging using a high field yokeless permanent magnet

International Nuclear Information System (INIS)

Kose, Katsumi; Haishi, Tomoyuki

2011-01-01

We measured the homogeneity and stability of the magnetic field of a high field (about 1.04 tesla) yokeless permanent magnet with 40-mm gap for high resolution nuclear magnetic resonance (NMR) imaging. Homogeneity was evaluated using a 3-dimensional (3D) lattice phantom and 3D spin-echo imaging sequences. In the central sphere (20-mm diameter), peak-to-peak magnetic field inhomogeneity was about 60 ppm, and the root-mean-square was 8 ppm. We measured room temperature, magnet temperature, and NMR frequency of the magnet simultaneously every minute for about 68 hours with and without the thermal insulator of the magnet. A simple mathematical model described the magnet's thermal property. Based on magnet performance, we performed high resolution (up to [20 μm] 2 ) imaging with internal NMR lock sequences of several biological samples. Our results demonstrated the usefulness of the high field small yokeless permanent magnet for high resolution NMR imaging. (author)

Progress in high-resolution x-ray holographic microscopy

International Nuclear Information System (INIS)

Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

1987-07-01

Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs

Progress in high-resolution x-ray holographic microscopy

Energy Technology Data Exchange (ETDEWEB)

Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

1987-07-01

Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs.

High-resolution spectroscopy of gases for industrial applications

DEFF Research Database (Denmark)

Fateev, Alexander; Clausen, Sønnik

High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing...... databases (e.g. HITRAN, HITEMP or CDSD) can normally be used for absorption spectra calculations at limited temperature/pressure ranges. Therefore experimental measurements of absorption/transmission spectra gases (e.g. CO2, H2O or SO2) at high-resolution and elevated temperatures are essential both...... for analysis of complex experimental data and further development of the databases. High-temperature gas cell facilities available at DTU Chemical Engineering are presented and described. The gas cells and high-resolution spectrometers allow us to perform high-quality reference measurements of gases relevant...

High-resolution of particle contacts via fluorophore exclusion in deep-imaging of jammed colloidal packings

Science.gov (United States)

Kyeyune-Nyombi, Eru; Morone, Flaviano; Liu, Wenwei; Li, Shuiqing; Gilchrist, M. Lane; Makse, Hernán A.

2018-01-01

Understanding the structural properties of random packings of jammed colloids requires an unprecedented high-resolution determination of the contact network providing mechanical stability to the packing. Here, we address the determination of the contact network by a novel strategy based on fluorophore signal exclusion of quantum dot nanoparticles from the contact points. We use fluorescence labeling schemes on particles inspired by biology and biointerface science in conjunction with fluorophore exclusion at the contact region. The method provides high-resolution contact network data that allows us to measure structural properties of the colloidal packing near marginal stability. We determine scaling laws of force distributions, soft modes, correlation functions, coordination number and free volume that define the universality class of jammed colloidal packings and can be compared with theoretical predictions. The contact detection method opens up further experimental testing at the interface of jamming and glass physics.

[Examination of upper abdominal region in high spatial resolution diffusion-weighted imaging using 3-Tesla MRI].

Science.gov (United States)

Terada, Masaki; Matsushita, Hiroki; Oosugi, Masanori; Inoue, Kazuyasu; Yaegashi, Taku; Anma, Takeshi

2009-03-20

The advantage of the higher signal-to-noise ratio (SNR) of 3-Tesla magnetic resonance imaging (3-Tesla) has the possibility of contributing to the improvement of high spatial resolution without causing image deterioration. In this study, we compared SNR and the apparent diffusion coefficient (ADC) value with 3-Tesla as the condition in the diffusion-weighted image (DWI) parameter of the 1.5-Tesla magnetic resonance imaging (1.5-Tesla) and we examined the high spatial resolution images in the imaging method [respiratory-triggering (RT) method and breath free (BF) method] and artifact (motion and zebra) in the upper abdominal region of DWI at 3-Tesla. We have optimized scan parameters based on phantom and in vivo study. As a result, 3-Tesla was able to obtain about 1.5 times SNR in comparison with the 1.5-Tesla, ADC value had few differences. Moreover, the RT method was effective in correcting the influence of respiratory movement in comparison with the BF method, and image improvement by the effective acquisition of SNR and reduction of the artifact were provided. Thus, DWI of upper abdominal region was a useful sequence for the high spatial resolution in 3-Tesla.

Towards high-resolution positron emission tomography for small volumes

International Nuclear Information System (INIS)

McKee, B.T.A.

1982-01-01

Some arguments are made regarding the medical usefulness of high spatial resolution in positron imaging, even if limited to small imaged volumes. Then the intrinsic limitations to spatial resolution in positron imaging are discussed. The project to build a small-volume, high resolution animal research prototype (SHARP) positron imaging system is described. The components of the system, particularly the detectors, are presented and brief mention is made of data acquisition and image reconstruction methods. Finally, some preliminary imaging results are presented; a pair of isolated point sources and 18 F in the bones of a rabbit. Although the detector system is not fully completed, these first results indicate that the goals of high sensitivity and high resolution (4 mm) have been realized. (Auth.)

High-resolution X-ray crystal structure of bovine H-protein using the high-pressure cryocooling method

International Nuclear Information System (INIS)

Higashiura, Akifumi; Ohta, Kazunori; Masaki, Mika; Sato, Masaru; Inaka, Koji; Tanaka, Hiroaki; Nakagawa, Atsushi

2013-01-01

Using the high-pressure cryocooling method, the high-resolution X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. This is the first ultra-high-resolution structure obtained from a high-pressure cryocooled crystal. Recently, many technical improvements in macromolecular X-ray crystallography have increased the number of structures deposited in the Protein Data Bank and improved the resolution limit of protein structures. Almost all high-resolution structures have been determined using a synchrotron radiation source in conjunction with cryocooling techniques, which are required in order to minimize radiation damage. However, optimization of cryoprotectant conditions is a time-consuming and difficult step. To overcome this problem, the high-pressure cryocooling method was developed (Kim et al., 2005 ▶) and successfully applied to many protein-structure analyses. In this report, using the high-pressure cryocooling method, the X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. Structural comparisons between high- and ambient-pressure cryocooled crystals at ultra-high resolution illustrate the versatility of this technique. This is the first ultra-high-resolution X-ray structure obtained using the high-pressure cryocooling method

High resolution drift chambers

International Nuclear Information System (INIS)

Va'vra, J.

1985-07-01

High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

Development of hybrid low-pressure MSGC neutron detectors

International Nuclear Information System (INIS)

Gebauer, B.; Alimov, S.S.; Klimov, A.Yu.; Levchanovski, F.V.; Litvinenko, E.I.; Nikiforov, A.S.; Prikhodko, V.I.; Richter, G.; Rogov, V.; Schulz, Ch.; Shashkin, V.I.; Wilhelm, M.; Wilpert, Th.

2004-01-01

For very high rate and resolution time-resolved experiments at next generation pulsed spallation neutron sources like ESS large-area hybrid low-pressure micro-strip gas chamber detectors are being developed. Due to their thin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of ∼100 μm and 8 cps. This will open up novel applications based on time-of-flight (TOF) and single-event detection with very high dynamic range, replacing integrating CCD and image plate detectors, e.g. in radiography/tomography, TOF Laue diffraction, single crystal diffraction and focusing low-Q SANS. In this conference report new results concerning the technical realization of this detector system are reported in conjunction with a brief summary of the detector principle and with reference to earlier results

High resolution neutron spectroscopy for helium isotopes

International Nuclear Information System (INIS)

Abdel-Wahab, M.S.; Klages, H.O.; Schmalz, G.; Haesner, B.H.; Kecskemeti, J.; Schwarz, P.; Wilczynski, J.

1992-01-01

A high resolution fast neutron time-of-flight spectrometer is described, neutron time-of-flight spectra are taken using a specially designed TDC in connection to an on-line computer. The high time-of-flight resolution of 5 ps/m enabled the study of the total cross section of 4 He for neutrons near the 3/2 + resonance in the 5 He nucleus. The resonance parameters were determined by a single level Breit-Winger fit to the data. (orig.)

A high-resolution regional reanalysis for Europe

Science.gov (United States)

Ohlwein, C.

2015-12-01

Reanalyses gain more and more importance as a source of meteorological information for many purposes and applications. Several global reanalyses projects (e.g., ERA, MERRA, CSFR, JMA9) produce and verify these data sets to provide time series as long as possible combined with a high data quality. Due to a spatial resolution down to 50-70km and 3-hourly temporal output, they are not suitable for small scale problems (e.g., regional climate assessment, meso-scale NWP verification, input for subsequent models such as river runoff simulations). The implementation of regional reanalyses based on a limited area model along with a data assimilation scheme is able to generate reanalysis data sets with high spatio-temporal resolution. Within the Hans-Ertel-Centre for Weather Research (HErZ), the climate monitoring branch concentrates efforts on the assessment and analysis of regional climate in Germany and Europe. In joint cooperation with DWD (German Meteorological Service), a high-resolution reanalysis system based on the COSMO model has been developed. The regional reanalysis for Europe matches the domain of the CORDEX EURO-11 specifications, albeit at a higher spatial resolution, i.e., 0.055° (6km) instead of 0.11° (12km) and comprises the assimilation of observational data using the existing nudging scheme of COSMO complemented by a special soil moisture analysis with boundary conditions provided by ERA-Interim data. The reanalysis data set covers the past 20 years. Extensive evaluation of the reanalysis is performed using independent observations with special emphasis on precipitation and high-impact weather situations indicating a better representation of small scale variability. Further, the evaluation shows an added value of the regional reanalysis with respect to the forcing ERA Interim reanalysis and compared to a pure high-resolution dynamical downscaling approach without data assimilation.

High-resolution cranial ultrasound in the shaken-baby syndrome

Energy Technology Data Exchange (ETDEWEB)

Chen, C.Y.; Chin, S.C.; Lee, C.C.; Lee, K.W. [Dept. of Radiology, Tri-Service General Hospital and National Defence Medical Centre, Taipei, Taiwan (Taiwan); Huang, C.C. [Dept. of Paediatrics, National Cheng Kung University Hospital, Tainan (Taiwan); Zimmerman, R.A. [Dept. of Radiology, Children' s Hospital of Philadelphia, PA (United States); Yuh, Y.S.; Chen, S.J. [Dept. of Paediatrics, Tri-Service General Hospital and National Defence Medical Centre, Neihu, Taipei (Taiwan)

2001-08-01

With limited near-field resolution and accessible acoustic windows, sonography has not been advocated for assessing central nervous system injuries in the shaken-baby syndrome. Our purpose was to correlate high-resolution ultrasonographic characteristics of central nervous system injuries in whiplash injuries and the shaken-baby-syndrome with MRI and CT. Ultrasonographic images of 13 infants, aged 2-12 months, with whiplash or shaking cranial trauma were reviewed and compared with MRI in 10 and CT in 10. Five patients had serial ultrasonography and MRI or CT follow-up from 1 to 4 months after the initial injury. With ultrasonography we identified 20 subdural haematomas. MRI and CT in 15 of these showed that four were hyperechoic in the acute stage, three were mildly echogenic in the subacute stage, and that one subacute and seven chronic lesions were echo-free. Five patients had acute focal or diffuse echogenic cortical oedema which evolved into subacute subcortical hyperechoic haemorrhage in four, and well-defined chronic sonolucent cystic or noncystic encephalomalacia was seen at follow-up in two. Using ultrasonography we were unable to detect two posterior cranial fossa subdural haematomas or subarachnoid haemorrhage in the basal cisterns in three cases, but did show blood in the interhemispheric cistern and convexity sulci in two. Ultrasonography has limitations in demonstrating abnormalities remote from the high cerebral convexities but may be a useful adjunct to CT and MRI in monitoring the progression of central nervous system injuries in infants receiving intensive care. (orig.)

High-resolution cranial ultrasound in the shaken-baby syndrome

International Nuclear Information System (INIS)

Chen, C.Y.; Chin, S.C.; Lee, C.C.; Lee, K.W.; Huang, C.C.; Zimmerman, R.A.; Yuh, Y.S.; Chen, S.J.

2001-01-01

With limited near-field resolution and accessible acoustic windows, sonography has not been advocated for assessing central nervous system injuries in the shaken-baby syndrome. Our purpose was to correlate high-resolution ultrasonographic characteristics of central nervous system injuries in whiplash injuries and the shaken-baby-syndrome with MRI and CT. Ultrasonographic images of 13 infants, aged 2-12 months, with whiplash or shaking cranial trauma were reviewed and compared with MRI in 10 and CT in 10. Five patients had serial ultrasonography and MRI or CT follow-up from 1 to 4 months after the initial injury. With ultrasonography we identified 20 subdural haematomas. MRI and CT in 15 of these showed that four were hyperechoic in the acute stage, three were mildly echogenic in the subacute stage, and that one subacute and seven chronic lesions were echo-free. Five patients had acute focal or diffuse echogenic cortical oedema which evolved into subacute subcortical hyperechoic haemorrhage in four, and well-defined chronic sonolucent cystic or noncystic encephalomalacia was seen at follow-up in two. Using ultrasonography we were unable to detect two posterior cranial fossa subdural haematomas or subarachnoid haemorrhage in the basal cisterns in three cases, but did show blood in the interhemispheric cistern and convexity sulci in two. Ultrasonography has limitations in demonstrating abnormalities remote from the high cerebral convexities but may be a useful adjunct to CT and MRI in monitoring the progression of central nervous system injuries in infants receiving intensive care. (orig.)

MRI of Retinal Free Radical Production With Laminar Resolution In Vivo

Science.gov (United States)

Berkowitz, Bruce A.; Lewin, Alfred S.; Biswal, Manas R.; Bredell, Bryce X.; Davis, Christopher; Roberts, Robin

2016-01-01

Purpose Recent studies have suggested the hypothesis that quench-assisted 1/T1 magnetic resonance imaging (MRI) measures free radical production with laminar resolution in vivo without the need of a contrast agent. Here, we test this hypothesis further by examining the spatial and detection sensitivity of quench-assisted 1/T1 MRI to strain, age, or retinal cell layer-specific genetic manipulations. Methods We studied: adult wild-type mice; mice at postnatal day 7 (P7); cre dependent retinal pigment epithelium (RPE)-specific MnSOD knockout mice; doxycycline-treated Sod2flox/flox mice lacking the cre transgene; and α-transducin knockout (Gnat1−/−) mice on a C57Bl/6 background. Transretinal 1/T1 profiles were mapped in vivo in the dark without or with antioxidant treatment, or followed by light exposure. We calibrated profiles spatially using optical coherence tomography. Results Dark-adapted RPE-specific MnSOD knockout mice had greater than normal 1/T1 in the RPE and outer nuclear layers that was corrected to wild-type levels by antioxidant treatment. Dark and light Gnat1−/− mice also had greater than normal outer retinal 1/T1 values. In adult wild-type mice, dark values of 1/T1 in the ellipsoid region and in the outer segment were suppressed by 13 minutes of light. By 29 minutes of light, 1/T1 reduction extended to the outer nuclear layer. Gnat1−/− mice demonstrated a faster light-evoked suppression of 1/T1 values in the outer retina. In P7 mice, transretinal 1/T1 profiles were the same in dark and light. Conclusions Quench-assisted MRI has the laminar resolution and detection sensitivity to evaluate normal and pathologic production of free radicals in vivo. PMID:26886890

Development Of High-Resolution Mechanical Spectroscopy, HRMS: Status And Perspectives. HRMS Coupled With A Laser Dilatometer

Directory of Open Access Journals (Sweden)

Magalas L.B.

2015-09-01

Full Text Available Recent achievements in the development of low-frequency high-resolution mechanical spectroscopy (HRMS are briefly reported. It is demonstrated that extremely low values of the loss angle, ϕ, (tanϕb = 1×10−5 can be measured as a function of frequency, and the precision in estimation of the dynamic modulus is better than 1×10−5 in arbitrary units. Three conditions must be fulfilled to obtain high resolution in subresonant and resonant mechanical loss measurements: (1 noise in stress and elastic strain signals must be lower than 70 dB, (2 high quality of stress and strain signals must be tested both in the frequency- and time-domains, and (3 the estimation of the mechanical loss and modulus must be verified by at least two different computing methods operating in the frequency- and time-domains. It is concluded that phase measurements in the subresonant domain are no longer determined by precision in estimation of the loss angle. Recent developments in high-resolution resonant mechanical loss measurements stem from the application of advanced nonparametric and parametric computing methods and algorithms to estimate the logarithmic decrement and the elastic modulus from exponentially damped free decaying oscillations embedded in experimental noise.

A computational atlas of the hippocampal formation using ex vivo, ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI

DEFF Research Database (Denmark)

Iglesias, Juan Eugenio; Augustinack, Jean C.; Nguyen, Khoa

2015-01-01

level using ultra-high resolution, ex vivo MRI. Fifteen autopsy samples were scanned at 0.13 mm isotropic resolution (on average) using customized hardware. The images were manually segmented into 13 different hippocampal substructures using a protocol specifically designed for this study; precise...... datasets with different types of MRI contrast. The results show that the atlas and companion segmentation method: 1) can segment T1 and T2 images, as well as their combination, 2) replicate findings on mild cognitive impairment based on high-resolution T2 data, and 3) can discriminate between Alzheimer......'s disease subjects and elderly controls with 88% accuracy in standard resolution (1 mm) T1 data, significantly outperforming the atlas in FreeSurfer version 5.3 (86% accuracy) and classification based on whole hippocampal volume (82% accuracy)....

Automated data processing of high-resolution mass spectra

DEFF Research Database (Denmark)

Hansen, Michael Adsetts Edberg; Smedsgaard, Jørn

of the massive amounts of data. We present an automated data processing method to quantitatively compare large numbers of spectra from the analysis of complex mixtures, exploiting the full quality of high-resolution mass spectra. By projecting all detected ions - within defined intervals on both the time...... infusion of crude extracts into the source taking advantage of the high sensitivity, high mass resolution and accuracy and the limited fragmentation. Unfortunately, there has not been a comparable development in the data processing techniques to fully exploit gain in high resolution and accuracy...... infusion analyses of crude extract to find the relationship between species from several species terverticillate Penicillium, and also that the ions responsible for the segregation can be identified. Furthermore the process can automate the process of detecting unique species and unique metabolites....

Brown dwarf distances and atmospheres: Spitzer Parallaxes and the Keck/NIRSPEC upgrade

Science.gov (United States)

Martin, Emily C.

2018-01-01

Advances in infrared technology have been essential towards improving our understanding of the solar neighborhood, revealing a large population of brown dwarfs, which span the mass regime between planets and stars. My thesis combines near-infrared (NIR) spectroscopic and astrometric analysis of nearby low-mass stars and brown dwarfs with instrumentation work to upgrade the NIRSPEC instrument for the Keck II Telescope. I will present results from a program using Spitzer/IRAC data to measure precise locations and distances to 22 of the coldest and closest brown dwarfs. These distances allow us to constrain absolute physical properties, such as mass, radius, and age, of free-floating planetary-mass objects through comparison to atmospheric and evolutionary models. NIR spectroscopy combined with the Spitzer photometry reveals a detailed look into the atmospheres of brown dwarfs and gaseous extrasolar planets. Additionally, I will discuss the improvements we are making to the NIRSPEC instrument at Keck. NIRSPEC is a NIR echelle spectrograph, capable of R~2000 and R~25,000 observations in the 1-5 μm range. As part of the upgrade, I performed detector characterization, optical design of a new slit-viewing camera, mechanical testing, and electronics design. NIRSPEC’s increased efficiency will allow us to obtain moderate- and high-resolution NIR spectra of objects up to a magnitude fainter than the current NIRSPEC design. Finally, I will demonstrate the utility of a NIR laser frequency comb as a high-resolution calibrator. This new technology will revolutionize precision radial velocity measurements in the coming decade.

Achieving sensitive, high-resolution laser spectroscopy at CRIS

Energy Technology Data Exchange (ETDEWEB)

Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

2017-11-15

The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

Simultaneous Confocal Scanning Laser Ophthalmoscopy Combined with High-Resolution Spectral-Domain Optical Coherence Tomography: A Review

Directory of Open Access Journals (Sweden)

Verônica Castro Lima

2011-01-01

Full Text Available We aimed to evaluate technical aspects and the clinical relevance of a simultaneous confocal scanning laser ophthalmoscope and a high-speed, high-resolution, spectral-domain optical coherence tomography (SDOCT device for retinal imaging. The principle of confocal scanning laser imaging provides a high resolution of retinal and choroidal vasculature with low light exposure. Enhanced contrast, details, and image sharpness are generated using confocality. The real-time SDOCT provides a new level of accuracy for assessment of the angiographic and morphological correlation. The combined system allows for simultaneous recordings of topographic and tomographic images with accurate correlation between them. Also it can provide simultaneous multimodal imaging of retinal pathologies, such as fluorescein and indocyanine green angiographies, infrared and blue reflectance (red-free images, fundus autofluorescence images, and OCT scans (Spectralis HRA + OCT; Heidelberg Engineering, Heidelberg, Germany. The combination of various macular diagnostic tools can lead to a better understanding and improved knowledge of macular diseases.

High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy.

Science.gov (United States)

Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R; Murshudov, Garib N; Short, Judith M; Scheres, Sjors H W; Henderson, Richard

2013-12-01

Three-dimensional (3D) structure determination by single particle electron cryomicroscopy (cryoEM) involves the calculation of an initial 3D model, followed by extensive iterative improvement of the orientation determination of the individual particle images and the resulting 3D map. Because there is much more noise than signal at high resolution in the images, this creates the possibility of noise reinforcement in the 3D map, which can give a false impression of the resolution attained. The balance between signal and noise in the final map at its limiting resolution depends on the image processing procedure and is not easily predicted. There is a growing awareness in the cryoEM community of how to avoid such over-fitting and over-estimation of resolution. Equally, there has been a reluctance to use the two principal methods of avoidance because they give lower resolution estimates, which some people believe are too pessimistic. Here we describe a simple test that is compatible with any image processing protocol. The test allows measurement of the amount of signal and the amount of noise from overfitting that is present in the final 3D map. We have applied the method to two different sets of cryoEM images of the enzyme beta-galactosidase using several image processing packages. Our procedure involves substituting the Fourier components of the initial particle image stack beyond a chosen resolution by either the Fourier components from an adjacent area of background, or by simple randomisation of the phases of the particle structure factors. This substituted noise thus has the same spectral power distribution as the original data. Comparison of the Fourier Shell Correlation (FSC) plots from the 3D map obtained using the experimental data with that from the same data with high-resolution noise (HR-noise) substituted allows an unambiguous measurement of the amount of overfitting and an accompanying resolution assessment. A simple formula can be used to calculate an

An atlas of high-resolution IRAS maps on nearby galaxies

Science.gov (United States)

Rice, Walter

1993-01-01

An atlas of far-infrared IRAS maps with near 1 arcmin angular resolution of 30 optically large galaxies is presented. The high-resolution IRAS maps were produced with the Maximum Correlation Method (MCM) image construction and enhancement technique developed at IPAC. The MCM technique, which recovers the spatial information contained in the overlapping detector data samples of the IRAS all-sky survey scans, is outlined and tests to verify the structural reliability and photometric integrity of the high-resolution maps are presented. The infrared structure revealed in individual galaxies is discussed. The atlas complements the IRAS Nearby Galaxy High-Resolution Image Atlas, the high-resolution galaxy images encoded in FITS format, which is provided to the astronomical community as an IPAC product.

Development of high speed integrated circuit for very high resolution timing measurements

International Nuclear Information System (INIS)

Mester, Christian

2009-10-01

A multi-channel high-precision low-power time-to-digital converter application specific integrated circuit for high energy physics applications has been designed and implemented in a 130 nm CMOS process. To reach a target resolution of 24.4 ps, a novel delay element has been conceived. This nominal resolution has been experimentally verified with a prototype, with a minimum resolution of 19 ps. To further improve the resolution, a new interpolation scheme has been described. The ASIC has been designed to use a reference clock with the LHC bunch crossing frequency of 40 MHz and generate all required timing signals internally, to ease to use within the framework of an LHC upgrade. Special care has been taken to minimise the power consumption. (orig.)

Development of high speed integrated circuit for very high resolution timing measurements

Energy Technology Data Exchange (ETDEWEB)

Mester, Christian

2009-10-15

A multi-channel high-precision low-power time-to-digital converter application specific integrated circuit for high energy physics applications has been designed and implemented in a 130 nm CMOS process. To reach a target resolution of 24.4 ps, a novel delay element has been conceived. This nominal resolution has been experimentally verified with a prototype, with a minimum resolution of 19 ps. To further improve the resolution, a new interpolation scheme has been described. The ASIC has been designed to use a reference clock with the LHC bunch crossing frequency of 40 MHz and generate all required timing signals internally, to ease to use within the framework of an LHC upgrade. Special care has been taken to minimise the power consumption. (orig.)

High-resolution MRI in detecting subareolar breast abscess.

Science.gov (United States)

Fu, Peifen; Kurihara, Yasuyuki; Kanemaki, Yoshihide; Okamoto, Kyoko; Nakajima, Yasuo; Fukuda, Mamoru; Maeda, Ichiro

2007-06-01

Because subareolar breast abscess has a high recurrence rate, a more effective imaging technique is needed to comprehensively visualize the lesions and guide surgery. We performed a high-resolution MRI technique using a microscopy coil to reveal the characteristics and extent of subareolar breast abscess. High-resolution MRI has potential diagnostic value in subareolar breast abscess. This technique can be used to guide surgery with the aim of reducing the recurrence rate.

Recent applications of gas chromatography with high-resolution mass spectrometry.

Science.gov (United States)

Špánik, Ivan; Machyňáková, Andrea

2018-01-01

Gas chromatography coupled to high-resolution mass spectrometry is a powerful analytical method that combines excellent separation power of gas chromatography with improved identification based on an accurate mass measurement. These features designate gas chromatography with high-resolution mass spectrometry as the first choice for identification and structure elucidation of unknown volatile and semi-volatile organic compounds. Gas chromatography with high-resolution mass spectrometry quantitative analyses was previously focused on the determination of dioxins and related compounds using magnetic sector type analyzers, a standing requirement of many international standards. The introduction of a quadrupole high-resolution time-of-flight mass analyzer broadened interest in this method and novel applications were developed, especially for multi-target screening purposes. This review is focused on the development and the most interesting applications of gas chromatography coupled to high-resolution mass spectrometry towards analysis of environmental matrices, biological fluids, and food safety since 2010. The main attention is paid to various approaches and applications of gas chromatography coupled to high-resolution mass spectrometry for non-target screening to identify contaminants and to characterize the chemical composition of environmental, food, and biological samples. The most interesting quantitative applications, where a significant contribution of gas chromatography with high-resolution mass spectrometry over the currently used methods is expected, will be discussed as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel intra-operative, high-resolution atrial mapping approach.

Science.gov (United States)

Yaksh, Ameeta; van der Does, Lisette J M E; Kik, Charles; Knops, Paul; Oei, Frans B S; van de Woestijne, Pieter C; Bekkers, Jos A; Bogers, Ad J J C; Allessie, Maurits A; de Groot, Natasja M S

2015-12-01

A new technique is demonstrated for extensive high-resolution intra-operative atrial mapping that will facilitate the localization of atrial fibrillation (AF) sources and identification of the substrate perpetuating AF. Prior to the start of extra-corporal circulation, a 8 × 24-electrode array (2-mm inter-electrode distance) is placed subsequently on all the right and left epicardial atrial sites, including Bachmann's bundle, for recording of unipolar electrograms during sinus rhythm and (induced) AF. AF is induced by high-frequency pacing at the right atrial free wall. A pacemaker wire stitched to the right atrium serves as a reference signal. The indifferent pole is connected to a steal wire fixed to subcutaneous tissue. Electrograms are recorded by a computerized mapping system and, after amplification (gain 1000), filtering (bandwidth 0.5-400 Hz), sampling (1 kHz) and analogue to digital conversion (16 bits), automatically stored on hard disk. During the mapping procedure, real-time visualization secures electrogram quality. Analysis will be performed offline. This technique was performed in 168 patients of 18 years and older, with coronary and/or structural heart disease, with or without AF, electively scheduled for cardiac surgery and a ventricular ejection fraction above 40 %. The mean duration of the entire mapping procedure including preparation time was 9 ± 2 min. Complications related to the mapping procedure during or after cardiac surgery were not observed. We introduce the first epicardial atrial mapping approach with a high resolution of ≥1728 recording sites which can be performed in a procedure time of only 9±2 mins. This mapping technique can potentially identify areas responsible for initiation and persistence of AF and hopefully can individualize both diagnosis and therapy of AF.

Photoionization of Ar2 at high resolution

International Nuclear Information System (INIS)

Dehmer, P.M.

1982-01-01

The relative photoionization cross section of Ar 2 was determined at a resolution of 0.07 A in the wavelength region from 800 to 850 A using a new photoionization mass spectrometer that combines a high intensity helium continuum lamp with a free supersonic molecular beam source. In the region studied, the photoionization cross section is dominated by autoionization of molecular Rydberg states, and the structure is diffuse owing to the combined effects of autoionization and predissociation. The molecular photoionization spectrum is extremely complex and shows little resemblence either to the corresponding atomic spectrum (indicating that the spectrum of the dimer is not simply a perturbed atomic spectrum) or to the molecular absorption spectrum at longer wavelengths. The regular vibrational progressions seen at longer wavelengths are absent above the first ionization potential. Detailed spectroscopic analysis is possible for only a small fraction of the observed features; however, vibrational intervals of 50--100 cm -1 suggest that some of the Rydberg states have B 2 Pi/sub 3/2g/ ionic cores. A comparison of the absorption and photoionization spectra shows that, at wavelengths shorter than approx.835 A, many of the excited states decay via mechanisms other than autoionization

Multi-resolution voxel phantom modeling: a high-resolution eye model for computational dosimetry.

Science.gov (United States)

Caracappa, Peter F; Rhodes, Ashley; Fiedler, Derek

2014-09-21

Voxel models of the human body are commonly used for simulating radiation dose with a Monte Carlo radiation transport code. Due to memory limitations, the voxel resolution of these computational phantoms is typically too large to accurately represent the dimensions of small features such as the eye. Recently reduced recommended dose limits to the lens of the eye, which is a radiosensitive tissue with a significant concern for cataract formation, has lent increased importance to understanding the dose to this tissue. A high-resolution eye model is constructed using physiological data for the dimensions of radiosensitive tissues, and combined with an existing set of whole-body models to form a multi-resolution voxel phantom, which is used with the MCNPX code to calculate radiation dose from various exposure types. This phantom provides an accurate representation of the radiation transport through the structures of the eye. Two alternate methods of including a high-resolution eye model within an existing whole-body model are developed. The accuracy and performance of each method is compared against existing computational phantoms.

High-resolution intravital microscopy.

Directory of Open Access Journals (Sweden)

Volker Andresen

Full Text Available Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy--the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and

High-Resolution Intravital Microscopy

Science.gov (United States)

Andresen, Volker; Pollok, Karolin; Rinnenthal, Jan-Leo; Oehme, Laura; Günther, Robert; Spiecker, Heinrich; Radbruch, Helena; Gerhard, Jenny; Sporbert, Anje; Cseresnyes, Zoltan; Hauser, Anja E.; Niesner, Raluca

2012-01-01

Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy - the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning) while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs) of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and developmental biology

Preliminary results from a high-pressure imaging spectroscopic proportional counter

International Nuclear Information System (INIS)

Hall, C.J.; Bazzano, A.; Lewis, R.A.; Parker, B.; Ubertini, P.; Worgan, J.S.

1992-01-01

A new type of high-pressure proportional counter, with both spatial resolution and spectroscopic capabilities is being jointly developed by the Istituto di Astrofisica Spaziale (CNR), Frascati, Italy and the SERC Daresbury Laboratory, Warrington, UK. The characteristics of the detector can be optimized for the particular requirement of the experiment, either for x-ray astronomy observations from space, or for the high count rate applications associated with a synchrotron light source. In its baseline configuration, the detector is filled to 5 bar with a xenon/quench gas mixture and will be sensitive over the energy range 5 keV to 150 keV (2.5 to 0.08 A). The positional resolution will range from 500 μm at the lower energies to around 1 mm at the higher end of the energy range. The current prototype has a sensitive area of 200x200 mm. The final version is hoped to have an area closer to 425x425 mm. The very small photon absorption length in the higher pressure gas allows the parallax effect, a feature of 1 atmosphere detectors, to be greatly reduced. The timing resolution (150 ns) of the detector enables both a high-rate capability and the possibility of the escape gate technique to achieve higher spectral resolution at energies > the Xe K edge. Preliminary results are presented showing the spectral and positional resolution for the prototype detector

Hyper-resolution urban flood modeling using high-resolution radar precipitation and LiDAR data

Science.gov (United States)

Noh, S. J.; Lee, S.; Lee, J.; Seo, D. J.

2016-12-01

Floods occur most frequently among all natural hazards, often causing widespread economic damage and loss of human lives. In particular, urban flooding is becoming increasingly costly and difficult to manage with a greater concentration of population and assets in urban centers. Despite of known benefits for accurate representation of small scale features and flow interaction among different flow domains, which have significant impact on flood propagation, high-resolution modeling has not been fully utilized due to expensive computation and various uncertainties from model structure, input and parameters. In this study, we assess the potential of hyper-resolution hydrologic-hydraulic modeling using high-resolution radar precipitation and LiDAR data for improved urban flood prediction and hazard mapping. We describe a hyper-resolution 1D-2D coupled urban flood model for pipe and surface flows and evaluate the accuracy of the street-level inundation information produced. For detailed geometric representation of urban areas and for computational efficiency, we use 1 m-resolution topographical data, processed from LiDAR measurements, in conjunction with adaptive mesh refinement. For street-level simulation in large urban areas at grid sizes of 1 to 10 m, a hybrid parallel computing scheme using MPI and openMP is also implemented in a high-performance computing system. The modeling approach developed is applied for the Johnson Creek Catchment ( 40 km2), which makes up the Arlington Urban Hydroinformatics Testbed. In addition, discussion will be given on availability of hyper-resolution simulation archive for improved real-time flood mapping.

Analysis of the impact of spatial resolution on land/water classifications using high-resolution aerial imagery

Science.gov (United States)

Enwright, Nicholas M.; Jones, William R.; Garber, Adrienne L.; Keller, Matthew J.

2014-01-01

Long-term monitoring efforts often use remote sensing to track trends in habitat or landscape conditions over time. To most appropriately compare observations over time, long-term monitoring efforts strive for consistency in methods. Thus, advances and changes in technology over time can present a challenge. For instance, modern camera technology has led to an increasing availability of very high-resolution imagery (i.e. submetre and metre) and a shift from analogue to digital photography. While numerous studies have shown that image resolution can impact the accuracy of classifications, most of these studies have focused on the impacts of comparing spatial resolution changes greater than 2 m. Thus, a knowledge gap exists on the impacts of minor changes in spatial resolution (i.e. submetre to about 1.5 m) in very high-resolution aerial imagery (i.e. 2 m resolution or less). This study compared the impact of spatial resolution on land/water classifications of an area dominated by coastal marsh vegetation in Louisiana, USA, using 1:12,000 scale colour-infrared analogue aerial photography (AAP) scanned at four different dot-per-inch resolutions simulating ground sample distances (GSDs) of 0.33, 0.54, 1, and 2 m. Analysis of the impact of spatial resolution on land/water classifications was conducted by exploring various spatial aspects of the classifications including density of waterbodies and frequency distributions in waterbody sizes. This study found that a small-magnitude change (1–1.5 m) in spatial resolution had little to no impact on the amount of water classified (i.e. percentage mapped was less than 1.5%), but had a significant impact on the mapping of very small waterbodies (i.e. waterbodies ≤ 250 m2). These findings should interest those using temporal image classifications derived from very high-resolution aerial photography as a component of long-term monitoring programs.

Spatial and molecular resolution of diffuse malignant mesothelioma heterogeneity by integrating label-free FTIR imaging, laser capture microdissection and proteomics

Science.gov (United States)

Großerueschkamp, Frederik; Bracht, Thilo; Diehl, Hanna C.; Kuepper, Claus; Ahrens, Maike; Kallenbach-Thieltges, Angela; Mosig, Axel; Eisenacher, Martin; Marcus, Katrin; Behrens, Thomas; Brüning, Thomas; Theegarten, Dirk; Sitek, Barbara; Gerwert, Klaus

2017-03-01

Diffuse malignant mesothelioma (DMM) is a heterogeneous malignant neoplasia manifesting with three subtypes: epithelioid, sarcomatoid and biphasic. DMM exhibit a high degree of spatial heterogeneity that complicates a thorough understanding of the underlying different molecular processes in each subtype. We present a novel approach to spatially resolve the heterogeneity of a tumour in a label-free manner by integrating FTIR imaging and laser capture microdissection (LCM). Subsequent proteome analysis of the dissected homogenous samples provides in addition molecular resolution. FTIR imaging resolves tumour subtypes within tissue thin-sections in an automated and label-free manner with accuracy of about 85% for DMM subtypes. Even in highly heterogeneous tissue structures, our label-free approach can identify small regions of interest, which can be dissected as homogeneous samples using LCM. Subsequent proteome analysis provides a location specific molecular characterization. Applied to DMM subtypes, we identify 142 differentially expressed proteins, including five protein biomarkers commonly used in DMM immunohistochemistry panels. Thus, FTIR imaging resolves not only morphological alteration within tissue but it resolves even alterations at the level of single proteins in tumour subtypes. Our fully automated workflow FTIR-guided LCM opens new avenues collecting homogeneous samples for precise and predictive biomarkers from omics studies.

Image Quality in High-resolution and High-cadence Solar Imaging

Science.gov (United States)

Denker, C.; Dineva, E.; Balthasar, H.; Verma, M.; Kuckein, C.; Diercke, A.; González Manrique, S. J.

2018-03-01

Broad-band imaging and even imaging with a moderate bandpass (about 1 nm) provides a photon-rich environment, where frame selection (lucky imaging) becomes a helpful tool in image restoration, allowing us to perform a cost-benefit analysis on how to design observing sequences for imaging with high spatial resolution in combination with real-time correction provided by an adaptive optics (AO) system. This study presents high-cadence (160 Hz) G-band and blue continuum image sequences obtained with the High-resolution Fast Imager (HiFI) at the 1.5-meter GREGOR solar telescope, where the speckle-masking technique is used to restore images with nearly diffraction-limited resolution. The HiFI employs two synchronized large-format and high-cadence sCMOS detectors. The median filter gradient similarity (MFGS) image-quality metric is applied, among others, to AO-corrected image sequences of a pore and a small sunspot observed on 2017 June 4 and 5. A small region of interest, which was selected for fast-imaging performance, covered these contrast-rich features and their neighborhood, which were part of Active Region NOAA 12661. Modifications of the MFGS algorithm uncover the field- and structure-dependency of this image-quality metric. However, MFGS still remains a good choice for determining image quality without a priori knowledge, which is an important characteristic when classifying the huge number of high-resolution images contained in data archives. In addition, this investigation demonstrates that a fast cadence and millisecond exposure times are still insufficient to reach the coherence time of daytime seeing. Nonetheless, the analysis shows that data acquisition rates exceeding 50 Hz are required to capture a substantial fraction of the best seeing moments, significantly boosting the performance of post-facto image restoration.

Smartphone microendoscopy for high resolution fluorescence imaging

Directory of Open Access Journals (Sweden)

Xiangqian Hong

2016-09-01

Full Text Available High resolution optical endoscopes are increasingly used in diagnosis of various medical conditions of internal organs, such as the cervix and gastrointestinal (GI tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this paper, we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 μm. Images collected from ex vivo, in vitro and in vivo samples using the device are also presented. The compact and cost-effective smartphone microendoscope may be envisaged as a powerful tool for detecting pre-cancerous lesions of internal organs in low and middle-income countries (LMICs.

Microlensing and Its Degeneracy Breakers: Parallax, Finite Source, High-Resolution Imaging, and Astrometry

Directory of Open Access Journals (Sweden)

Chien-Hsiu Lee

2017-07-01

Full Text Available First proposed by Paczynski in 1986, microlensing has been instrumental in the search for compact dark matter as well as discovery and characterization of exoplanets. In this article, we provide a brief history of microlensing, especially on the discoveries of compact objects and exoplanets. We then review the basics of microlensing and how astrometry can help break the degeneracy, providing a more robust determination of the nature of the microlensing events. We also outline prospects that will be made by on-going and forth-coming experiments/observatories.

High resolution mid-infrared spectroscopy based on frequency upconversion

DEFF Research Database (Denmark)

Dam, Jeppe Seidelin; Hu, Qi; Tidemand-Lichtenberg, Peter

2013-01-01

signals can be analyzed. The obtainable frequency resolution is usually in the nm range where sub nm resolution is preferred in many applications, like gas spectroscopy. In this work we demonstrate how to obtain sub nm resolution when using upconversion. In the presented realization one object point...... high resolution spectral performance by observing emission from hot water vapor in a butane gas burner....

Climate change and high-resolution whole-building numerical modelling

NARCIS (Netherlands)

Blocken, B.J.E.; Briggen, P.M.; Schellen, H.L.; Hensen, J.L.M.

2010-01-01

This paper briefly discusses the need of high-resolution whole-building numerical modelling in the context of climate change. High-resolution whole-building numerical modelling can be used for detailed analysis of the potential consequences of climate change on buildings and to evaluate remedial

New approach to 3-D, high sensitivity, high mass resolution space plasma composition measurements

International Nuclear Information System (INIS)

McComas, D.J.; Nordholt, J.E.

1990-01-01

This paper describes a new type of 3-D space plasma composition analyzer. The design combines high sensitivity, high mass resolution measurements with somewhat lower mass resolution but even higher sensitivity measurements in a single compact and robust design. While the lower resolution plasma measurements are achieved using conventional straight-through time-of-flight mass spectrometry, the high mass resolution measurements are made by timing ions reflected in a linear electric field (LEF), where the restoring force that an ion experiences is proportional to the depth it travels into the LEF region. Consequently, the ion's equation of motion in that dimension is that of a simple harmonic oscillator and its travel time is simply proportional to the square root of the ion's mass/charge (m/q). While in an ideal LEF, the m/q resolution can be arbitrarily high, in a real device the resolution is limited by the field linearity which can be achieved. In this paper we describe how a nearly linear field can be produced and discuss how the design can be optimized for various different plasma regimes and spacecraft configurations

High resolution CT of the chest

Energy Technology Data Exchange (ETDEWEB)

Barneveld Binkhuysen, F H [Eemland Hospital (Netherlands), Dept. of Radiology

1996-12-31

Compared to conventional CT high resolution CT (HRCT) shows several extra anatomical structures which might effect both diagnosis and therapy. The extra anatomical structures were discussed briefly in this article. (18 refs.).

Methodology of high-resolution photography for mural condition database

Science.gov (United States)

Higuchi, R.; Suzuki, T.; Shibata, M.; Taniguchi, Y.

2015-08-01

Digital documentation is one of the most useful techniques to record the condition of cultural heritage. Recently, high-resolution images become increasingly useful because it is possible to show general views of mural paintings and also detailed mural conditions in a single image. As mural paintings are damaged by environmental stresses, it is necessary to record the details of painting condition on high-resolution base maps. Unfortunately, the cost of high-resolution photography and the difficulty of operating its instruments and software have commonly been an impediment for researchers and conservators. However, the recent development of graphic software makes its operation simpler and less expensive. In this paper, we suggest a new approach to make digital heritage inventories without special instruments, based on our recent our research project in Üzümlü church in Cappadocia, Turkey. This method enables us to achieve a high-resolution image database with low costs, short time, and limited human resources.

Grid-free compressive beamforming

DEFF Research Database (Denmark)

Xenaki, Angeliki; Gerstoft, Peter

2015-01-01

sparsity on a continuous optimization variable. The DOA estimation problem with infinitely many unknowns, i.e., source locations and amplitudes, is solved over a few optimization variables with semidefinite programming. The grid-free CS reconstruction provides high-resolution imaging even with non...

Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment

International Nuclear Information System (INIS)

Li, Guang; Wei, Jie; Kadbi, Mo; Moody, Jason; Sun, August; Zhang, Shirong; Markova, Svetlana; Zakian, Kristen; Hunt, Margie; Deasy, Joseph O.

2017-01-01

Purpose: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. Methods and Materials: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board–approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm"3) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm"3). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. Results: Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (<0.05). The detected motion differences between TR-4DMRI and 3D cine were −0.2 ± 0.5 mm (phantom) and −0.2 ± 1.9 mm (diaphragms). Conclusion: Super-resolution TR-4DMRI has been

Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment

Energy Technology Data Exchange (ETDEWEB)

Li, Guang, E-mail: lig2@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Wei, Jie [Department of Computer Science, City College of New York, New York, New York (United States); Kadbi, Mo [Philips Healthcare, MR Therapy Cleveland, Ohio (United States); Moody, Jason; Sun, August; Zhang, Shirong; Markova, Svetlana; Zakian, Kristen; Hunt, Margie; Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States)

2017-06-01

Purpose: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. Methods and Materials: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board–approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm{sup 3}) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm{sup 3}). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. Results: Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (<0.05). The detected motion differences between TR-4DMRI and 3D cine were −0.2 ± 0.5 mm (phantom) and −0.2 ± 1.9 mm (diaphragms). Conclusion: Super-resolution TR-4

High-Resolution MRI in Rectal Cancer

International Nuclear Information System (INIS)

Dieguez, Adriana

2010-01-01

High-resolution MRI is the best method of assessing the relation of the rectal tumor with the potential circumferential resection margin (CRM). Therefore it is currently considered the method of choice for local staging of rectal cancer. The primary surgery of rectal cancer is total mesorectal excision (TME), which plane of dissection is formed by the mesorectal fascia surrounding mesorectal fat and rectum. This fascia will determine the circumferential margin of resection. At the same time, high resolution MRI allows adequate pre-operative identification of important prognostic risk factors, improving the selection and indication of therapy for each patient. This information includes, besides the circumferential margin of resection, tumor and lymph node staging, extramural vascular invasion and the description of lower rectal tumors. All these should be described in detail in the report, being part of the discussion in the multidisciplinary team, the place where the decisions involving the patient with rectal cancer will take place. The aim of this study is to provide the information necessary to understand the use of high resolution MRI in the identification of prognostic risk factors in rectal cancer. The technical requirements and standardized report for this study will be describe, as well as the anatomical landmarks of importance for the total mesorectal excision (TME), as we have said is the surgery of choice for rectal cancer. (authors) [es

High resolution humidity, temperature and aerosol profiling with MeteoSwiss Raman lidar

Science.gov (United States)

Dinoev, Todor; Arshinov, Yuri; Bobrovnikov, Sergei; Serikov, Ilya; Calpini, Bertrand; van den Bergh, Hubert; Parlange, Marc B.; Simeonov, Valentin

2010-05-01

Meteorological services rely, in part, on numerical weather prediction (NWP). Twice a day radiosonde observations of water vapor provide the required data for assimilation but this time resolution is insufficient to resolve certain meteorological phenomena. High time resolution temperature profiles from microwave radiometers are available as well but have rather low vertical resolution. The Raman LIDARs are able to provide temperature and humidity profiles with high time and range resolution, suitable for NWP model assimilation and validation. They are as well indispensible tools for continuous aerosol profiling for high resolution atmospheric boundary layer studies. To improve the database available for direct meteorological applications the Swiss meteo-service (MeteoSwiss), the Swiss Federal Institute of Technology in Lausanne (EPFL) and the Swiss National Science Foundation (SNSF) initiated a project to design and build an automated Raman lidar for day and night vertical profiling of tropospheric water vapor with the possibility to further upgrade it with an aerosol and temperature channels. The project was initiated in 2004 and RALMO (Raman Lidar for meteorological observations) was inaugurated in August 2008 at MeteoSwiss aerological station at Payerne. RALMO is currently operational and continuously profiles water vapor mixing ratio, aerosol backscatter ratio and aerosol extinction. The instrument is a fully automated, self-contained, eye-safe Raman lidar operated at 355 nm. Narrow field-of-view multi-telescope receiver and narrow band detection allow day and night-time vertical profiling of the atmospheric humidity. The rotational-vibrational Raman lidar responses from water vapor and nitrogen are spectrally separated by a high-throughput fiber coupled diffraction grating polychromator. The elastic backscatter and pure-rotational Raman lidar responses (PRR) from oxygen and nitrogen are spectrally isolated by a double grating polychromator and are used to

High-resolution coherent three-dimensional spectroscopy of Br2.

Science.gov (United States)

Chen, Peter C; Wells, Thresa A; Strangfeld, Benjamin R

2013-07-25

In the past, high-resolution spectroscopy has been limited to small, simple molecules that yield relatively uncongested spectra. Larger and more complex molecules have a higher density of peaks and are susceptible to complications (e.g., effects from conical intersections) that can obscure the patterns needed to resolve and assign peaks. Recently, high-resolution coherent two-dimensional (2D) spectroscopy has been used to resolve and sort peaks into easily identifiable patterns for molecules where pattern-recognition has been difficult. For very highly congested spectra, however, the ability to resolve peaks using coherent 2D spectroscopy is limited by the bandwidth of instrumentation. In this article, we introduce and investigate high-resolution coherent three-dimensional spectroscopy (HRC3D) as a method for dealing with heavily congested systems. The resulting patterns are unlike those in high-resolution coherent 2D spectra. Analysis of HRC3D spectra could provide a means for exploring the spectroscopy of large and complex molecules that have previously been considered too difficult to study.

High resolution gamma-ray spectroscopy at high count rates with a prototype High Purity Germanium detector

Science.gov (United States)

Cooper, R. J.; Amman, M.; Vetter, K.

2018-04-01

High-resolution gamma-ray spectrometers are required for applications in nuclear safeguards, emergency response, and fundamental nuclear physics. To overcome one of the shortcomings of conventional High Purity Germanium (HPGe) detectors, we have developed a prototype device capable of achieving high event throughput and high energy resolution at very high count rates. This device, the design of which we have previously reported on, features a planar HPGe crystal with a reduced-capacitance strip electrode geometry. This design is intended to provide good energy resolution at the short shaping or digital filter times that are required for high rate operation and which are enabled by the fast charge collection afforded by the planar geometry crystal. In this work, we report on the initial performance of the system at count rates up to and including two million counts per second.

Detectors for high resolution dynamic pet

International Nuclear Information System (INIS)

Derenzo, S.E.; Budinger, T.F.; Huesman, R.H.

1983-05-01

This report reviews the motivation for high spatial resolution in dynamic positron emission tomography of the head and the technical problems in realizing this objective. We present recent progress in using small silicon photodiodes to measure the energy deposited by 511 keV photons in small BGO crystals with an energy resolution of 9.4% full-width at half-maximum. In conjunction with a suitable phototube coupled to a group of crystals, the photodiode signal to noise ratio is sufficient for the identification of individual crystals both for conventional and time-of-flight positron tomography

Special issue on high-resolution optical imaging

Science.gov (United States)

Smith, Peter J. S.; Davis, Ilan; Galbraith, Catherine G.; Stemmer, Andreas

2013-09-01

The pace of development in the field of advanced microscopy is truly breath-taking, and is leading to major breakthroughs in our understanding of molecular machines and cell function. This special issue of Journal of Optics draws attention to a number of interesting approaches, ranging from fluorescence and imaging of unlabelled cells, to computational methods, all of which are describing the ever increasing detail of the dynamic behaviour of molecules in the living cell. This is a field which traditionally, and currently, demonstrates a marvellous interplay between the disciplines of physics, chemistry and biology, where apparent boundaries to resolution dissolve and living cells are viewed in ever more clarity. It is fertile ground for those interested in optics and non-conventional imaging to contribute high-impact outputs in the fields of cell biology and biomedicine. The series of articles presented here has been selected to demonstrate this interdisciplinarity and to encourage all those with a background in the physical sciences to 'dip their toes' into the exciting and dynamic discoveries surrounding cell function. Although single molecule super-resolution microscopy is commercially available, specimen preparation and interpretation of single molecule data remain a major challenge for scientists wanting to adopt the techniques. The paper by Allen and Davidson [1] provides a much needed detailed introduction to the practical aspects of stochastic optical reconstruction microscopy, including sample preparation, image acquisition and image analysis, as well as a brief description of the different variants of single molecule localization microscopy. Since super-resolution microscopy is no longer restricted to three-dimensional imaging of fixed samples, the review by Fiolka [2] is a timely introduction to techniques that have been successfully applied to four-dimensional live cell super-resolution microscopy. The combination of multiple high-resolution techniques

A Concept of Multi-Mode High Spectral Resolution Lidar Using Mach-Zehnder Interferometer

Directory of Open Access Journals (Sweden)

Jin Yoshitaka

2016-01-01

Full Text Available In this paper, we present the design of a High Spectral Resolution Lidar (HSRL using a laser that oscillates in a multi-longitudinal mode. Rayleigh and Mie scattering components are separated using a Mach-Zehnder Interferometer (MZI with the same free spectral range (FSR as the transmitted laser. The transmitted laser light is measured as a reference signal with the same MZI. By scanning the MZI periodically with a scanning range equal to the mode spacing, we can identify the maximum Mie and the maximum Rayleigh signals using the reference signal. The cross talk due to the spectral width of each laser mode can also be estimated.

High Resolution Thermometry for EXACT

Science.gov (United States)

Panek, J. S.; Nash, A. E.; Larson, M.; Mulders, N.

2000-01-01

High Resolution Thermometers (HRTs) based on SQUID detection of the magnetization of a paramagnetic salt or a metal alloy has been commonly used for sub-nano Kelvin temperature resolution in low temperature physics experiments. The main applications to date have been for temperature ranges near the lambda point of He-4 (2.177 K). These thermometers made use of materials such as Cu(NH4)2Br4 *2H2O, GdCl3, or PdFe. None of these materials are suitable for EXACT, which will explore the region of the He-3/He-4 tricritical point at 0.87 K. The experiment requirements and properties of several candidate paramagnetic materials will be presented, as well as preliminary test results.

High temperature and high resolution uv photoelectron spectroscopy using supersonic molecular beams

International Nuclear Information System (INIS)

Wang, Lai-Sheng; Reutt-Robey, J.E.; Niu, B.; Lee, Y.T.; Shirley, D.A.

1989-07-01

A high temperature molecular beam source with electron bombardment heating has been built for high resolution photoelectron spectroscopic studies of high temperature species and clusters. This source has the advantages of: producing an intense, continuous, seeded molecular beam, eliminating the interference of the heating mechanism from the photoelectron measurement. Coupling the source with our hemispherical electron energy analyzer, we can obtain very high resolution HeIα (584 angstrom) photoelectron spectra of high temperature species. Vibrationally-resolved photoelectron spectra of PbSe, As 2 , As 4 , and ZnCl 2 are shown to demonstrate the performance of the new source. 25 refs., 8 figs., 1 tab

Development and Performance Verification of the GANDALF High-Resolution Transient Recorder System

CERN Document Server

Bartknecht, Stefan; Herrmann, Florian; Königsmann, Kay; Lauser, Louis; Schill, Christian; Schopferer, Sebastian; Wollny, Heiner

2011-01-01

With present-day detectors in high energy physics one often faces fast analog pulses of a few nanoseconds length which cover large dynamic ranges. In many experiments both amplitude and timing information have to be measured with high accuracy. Additionally, the data rate per readout channel can reach several MHz, which leads to high demands on the separation of pile-up pulses. For an upgrade of the COMPASS experiment at CERN we have designed the GANDALF transient recorder with a resolution of 12bit@1GS/s and an analog bandwidth of 500\\:MHz. Signals are digitized with high precision and processed by fast algorithms to extract pulse arrival times and amplitudes in real-time and to generate trigger signals for the experiment. With up to 16 analog channels, deep memories and a high data rate interface, this 6U-VME64x/VXS module is not only a dead-time free digitization unit but also has huge numerical capabilities provided by the implementation of a Virtex5-SXT FPGA. Fast algorithms implemented in the FPGA may b...

Ribbon scanning confocal for high-speed high-resolution volume imaging of brain.

Directory of Open Access Journals (Sweden)

Alan M Watson

Full Text Available Whole-brain imaging is becoming a fundamental means of experimental insight; however, achieving subcellular resolution imagery in a reasonable time window has not been possible. We describe the first application of multicolor ribbon scanning confocal methods to collect high-resolution volume images of chemically cleared brains. We demonstrate that ribbon scanning collects images over ten times faster than conventional high speed confocal systems but with equivalent spectral and spatial resolution. Further, using this technology, we reconstruct large volumes of mouse brain infected with encephalitic alphaviruses and demonstrate that regions of the brain with abundant viral replication were inaccessible to vascular perfusion. This reveals that the destruction or collapse of large regions of brain micro vasculature may contribute to the severe disease caused by Venezuelan equine encephalitis virus. Visualization of this fundamental impact of infection would not be possible without sampling at subcellular resolution within large brain volumes.

A full-sky, high-resolution atlas of galactic 12 μm dust emission with WISE

International Nuclear Information System (INIS)

Meisner, Aaron M.; Finkbeiner, Douglas P.

2014-01-01

We describe our custom processing of the entire Wide-field Infrared Survey Explorer (WISE) 12 μm imaging data set, and present a high-resolution, full-sky map of diffuse Galactic dust emission that is free of compact sources and other contaminating artifacts. The principal distinctions between our resulting co-added images and the WISE Atlas stacks are our removal of compact sources, including their associated electronic and optical artifacts, and our preservation of spatial modes larger than 1.°5. We provide access to the resulting full-sky map via a set of 430 12.°5 × 12.°5 mosaics. These stacks have been smoothed to 15'' resolution and are accompanied by corresponding coverage maps, artifact images, and bit-masks for point sources, resolved compact sources, and other defects. When combined appropriately with other mid-infrared and far-infrared data sets, we expect our WISE 12 μm co-adds to form the basis for a full-sky dust extinction map with angular resolution several times better than Schlegel et al.

High resolution tsunami inversion for 2010 Chile earthquake

Directory of Open Access Journals (Sweden)

T.-R. Wu

2011-12-01

Full Text Available We investigate the feasibility of inverting high-resolution vertical seafloor displacement from tsunami waveforms. An inversion method named "SUTIM" (small unit tsunami inversion method is developed to meet this goal. In addition to utilizing the conventional least-square inversion, this paper also enhances the inversion resolution by Grid-Shifting method. A smooth constraint is adopted to gain stability. After a series of validation and performance tests, SUTIM is used to study the 2010 Chile earthquake. Based upon data quality and azimuthal distribution, we select tsunami waveforms from 6 GLOSS stations and 1 DART buoy record. In total, 157 sub-faults are utilized for the high-resolution inversion. The resolution reaches 10 sub-faults per wavelength. The result is compared with the distribution of the aftershocks and waveforms at each gauge location with very good agreement. The inversion result shows that the source profile features a non-uniform distribution of the seafloor displacement. The highly elevated vertical seafloor is mainly concentrated in two areas: one is located in the northern part of the epicentre, between 34° S and 36° S; the other is in the southern part, between 37° S and 38° S.

High resolution tsunami inversion for 2010 Chile earthquake

Science.gov (United States)

Wu, T.-R.; Ho, T.-C.

2011-12-01

We investigate the feasibility of inverting high-resolution vertical seafloor displacement from tsunami waveforms. An inversion method named "SUTIM" (small unit tsunami inversion method) is developed to meet this goal. In addition to utilizing the conventional least-square inversion, this paper also enhances the inversion resolution by Grid-Shifting method. A smooth constraint is adopted to gain stability. After a series of validation and performance tests, SUTIM is used to study the 2010 Chile earthquake. Based upon data quality and azimuthal distribution, we select tsunami waveforms from 6 GLOSS stations and 1 DART buoy record. In total, 157 sub-faults are utilized for the high-resolution inversion. The resolution reaches 10 sub-faults per wavelength. The result is compared with the distribution of the aftershocks and waveforms at each gauge location with very good agreement. The inversion result shows that the source profile features a non-uniform distribution of the seafloor displacement. The highly elevated vertical seafloor is mainly concentrated in two areas: one is located in the northern part of the epicentre, between 34° S and 36° S; the other is in the southern part, between 37° S and 38° S.

TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. II. CEP A AND NGC 7538

International Nuclear Information System (INIS)

Moscadelli, L.; Reid, M. J.; Menten, K. M.; Brunthaler, A.; Xu, Y.; Zheng, X. W.

2009-01-01

We report trigonometric parallaxes for the sources NGC 7538 and Cep A, corresponding to distances of 2.65 +0.12 -0.11 and 0.70 +0.04 -0.04 kpc, respectively. The distance to NGC 7538 is considerably smaller than its kinematic distance and places it in the Perseus spiral arm. The distance to Cep A is also smaller than its kinematic distance and places it in the L ocalarm or spur. Combining the distance and proper motions with observed radial velocities gives the location and full space motion of the star-forming regions. We find significant deviations from circular galactic orbits for these sources: both sources show large peculiar motions (greater than 10 km s -1 ) counter to galactic rotation and NGC 7538 has a comparable peculiar motion toward the Galactic center.

Validation of ERS-1 and high-resolution satellite gravity with in-situ shipborne gravity over the Indian offshore regions: Accuracies and implications to subsurface modeling

Digital Repository Service at National Institute of Oceanography (India)

Chatterjee, S.; Bhattacharyya, R.; Michael, L.; Krishna, K.S.; Majumdar, T.J.

Geoid and gravity anomalies derived from satellite altimetry are gradually gaining importance in marine geoscientific investigations. Keeping this in mind, we have validated ERS-1 (168 day repeat) altimeter data and very high-resolution free...

Concept for a new high resolution high intensity diffractometer

Energy Technology Data Exchange (ETDEWEB)

Stuhr, U [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

A concept of a new time-of-flight powder-diffractometer for a thermal neutral beam tube at SINQ is presented. The design of the instrument optimises the contradictory conditions of high intensity and high resolution. The high intensity is achieved by using many neutron pulses simultaneously. By analysing the time-angle-pattern of the detected neutrons an assignment of the neutrons to a single pulse is possible. (author) 3 figs., tab., refs.

THE BROWN DWARF KINEMATICS PROJECT (BDKP). III. PARALLAXES FOR 70 ULTRACOOL DWARFS

International Nuclear Information System (INIS)

Faherty, Jacqueline K.; Shara, Michael M.; Cruz, Kelle L.; Burgasser, Adam J.; Walter, Frederick M.; Van der Bliek, Nicole; West, Andrew A.; Vrba, Frederick J.; Anglada-Escudé, Guillem

2012-01-01

We report parallax measurements for 70 ultracool dwarfs (UCDs) including 11 late-M, 32 L, and 27 T dwarfs. In this sample, 14 M and L dwarfs exhibit low surface gravity features, 6 are close binary systems, and 2 are metal-poor subdwarfs. We combined our new measurements with 114 previously published UCD parallaxes and optical-mid-IR photometry to examine trends in spectral-type/absolute magnitude, and color-color diagrams. We report new polynomial relations between spectral type and M JHK . Including resolved L/T transition binaries in the relations, we find no reason to differentiate between a 'bright' (unresolved binary) and a 'faint' (single source) sample across the L/T boundary. Isolating early T dwarfs, we find that the brightening of T0-T4 sources is prominent in M J where there is a [1.2-1.4] mag difference. A similar yet dampened brightening of [0.3-0.5] mag happens at M H and a plateau or dimming of [–0.2 to –0.3] mag is seen in M K . Comparison with evolutionary models that vary gravity, metallicity, and cloud thickness verifies that for L into T dwarfs, decreasing cloud thickness reproduces brown dwarf near-IR color-magnitude diagrams. However we find that a near constant temperature of 1200 ±100 K along a narrow spectral subtype of T0-T4 is required to account for the brightening and color-magnitude diagram of the L-dwarf/T-dwarf transition. There is a significant population of both L and T dwarfs which are red or potentially 'ultra-cloudy' compared to the models, many of which are known to be young indicating a correlation between enhanced photospheric dust and youth. For the low surface gravity or young companion L dwarfs we find that 8 out of 10 are at least [0.2-1.0] mag underluminous in M JH and/or M K compared to equivalent spectral type objects. We speculate that this is a consequence of increased dust opacity and conclude that low surface gravity L dwarfs require a completely new spectral-type/absolute magnitude polynomial for analysis.

THE BROWN DWARF KINEMATICS PROJECT (BDKP). III. PARALLAXES FOR 70 ULTRACOOL DWARFS

Energy Technology Data Exchange (ETDEWEB)

Faherty, Jacqueline K.; Shara, Michael M.; Cruz, Kelle L. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034 (United States); Burgasser, Adam J. [Center of Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, CA 92093 (United States); Walter, Frederick M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Van der Bliek, Nicole [CTIO/National Optical Astronomy Observatory (Chile); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Ave Boston, MA 02215 (United States); Vrba, Frederick J. [US Naval Observatory, Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002 (United States); Anglada-Escude, Guillem, E-mail: jfaherty@amnh.org [Department of Terrestrial Magnetism, Carnegie Institution of Washington 5241 Broad Branch Road, NW, Washington, DC 20015 (United States)

2012-06-10

We report parallax measurements for 70 ultracool dwarfs (UCDs) including 11 late-M, 32 L, and 27 T dwarfs. In this sample, 14 M and L dwarfs exhibit low surface gravity features, 6 are close binary systems, and 2 are metal-poor subdwarfs. We combined our new measurements with 114 previously published UCD parallaxes and optical-mid-IR photometry to examine trends in spectral-type/absolute magnitude, and color-color diagrams. We report new polynomial relations between spectral type and M{sub JHK}. Including resolved L/T transition binaries in the relations, we find no reason to differentiate between a 'bright' (unresolved binary) and a 'faint' (single source) sample across the L/T boundary. Isolating early T dwarfs, we find that the brightening of T0-T4 sources is prominent in M{sub J} where there is a [1.2-1.4] mag difference. A similar yet dampened brightening of [0.3-0.5] mag happens at M{sub H} and a plateau or dimming of [-0.2 to -0.3] mag is seen in M{sub K} . Comparison with evolutionary models that vary gravity, metallicity, and cloud thickness verifies that for L into T dwarfs, decreasing cloud thickness reproduces brown dwarf near-IR color-magnitude diagrams. However we find that a near constant temperature of 1200 {+-}100 K along a narrow spectral subtype of T0-T4 is required to account for the brightening and color-magnitude diagram of the L-dwarf/T-dwarf transition. There is a significant population of both L and T dwarfs which are red or potentially 'ultra-cloudy' compared to the models, many of which are known to be young indicating a correlation between enhanced photospheric dust and youth. For the low surface gravity or young companion L dwarfs we find that 8 out of 10 are at least [0.2-1.0] mag underluminous in M{sub JH} and/or M{sub K} compared to equivalent spectral type objects. We speculate that this is a consequence of increased dust opacity and conclude that low surface gravity L dwarfs require a completely new

Volumetric expiratory high-resolution CT of the lung

International Nuclear Information System (INIS)

Nishino, Mizuki; Hatabu, Hiroto

2004-01-01

We developed a volumetric expiratory high-resolution CT (HRCT) protocol that provides combined inspiratory and expiratory volumetric imaging of the lung without increasing radiation exposure, and conducted a preliminary feasibility assessment of this protocol to evaluate diffuse lung disease with small airway abnormalities. The volumetric expiratory high-resolution CT increased the detectability of the conducting airway to the areas of air trapping (P<0.0001), and added significant information about extent and distribution of air trapping (P<0.0001)

Developing Visual Editors for High-Resolution Haptic Patterns

DEFF Research Database (Denmark)

Cuartielles, David; Göransson, Andreas; Olsson, Tony

2012-01-01

In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit high...... resolution haptic patterns so that they translate naturally to the user’s haptic experience. To solve this question we have developed and tested several visual editors...

High resolution SETI: Experiences and prospects

Science.gov (United States)

Horowitz, Paul; Clubok, Ken

Megachannel spectroscopy with sub-Hertz resolution constitutes an attractive strategy for a microwave search for extraterrestrial intelligence (SETI), assuming the transmission of a narrowband radiofrequency beacon. Such resolution matches the properties of the interstellar medium, and the necessary Doppler corrections provide a high degree of interference rejection. We have constructed a frequency-agile receiver with an FFT-based 8 megachannel digital spectrum analyzer, on-line signal recognition, and multithreshold archiving. We are using it to conduct a meridian transit search of the northern sky at the Harvard-Smithsonian 26-m antenna, with a second identical system scheduled to begin observations in Argentina this month. Successive 400 kHz spectra, at 0.05 Hz resolution, are searched for features characteristic of an intentional narrowband beacon transmission. These spectra are centered on guessable frequencies (such as λ21 cm), referenced successively to the local standard of rest, the galactic barycenter, and the cosmic blackbody rest frame. This search has rejected interference admirably, but is greatly limited both in total frequency coverage and sensitivity to signals other than carriers. We summarize five years of high resolution SETI at Harvard, in the context of answering the questions "How useful is narrowband SETI, how serious are its limitations, what can be done to circumvent them, and in what direction should SETI evolve?" Increasingly powerful signal processing hardware, combined with ever-higher memory densities, are particularly relevant, permitting the construction of compact and affordable gigachannel spectrum analyzers covering hundreds of megahertz of instantaneous bandwidth.

The high-resolution regional reanalysis COSMO-REA6

Science.gov (United States)

Ohlwein, C.

2016-12-01

Reanalyses gain more and more importance as a source of meteorological information for many purposes and applications. Several global reanalyses projects (e.g., ERA, MERRA, CSFR, JMA9) produce and verify these data sets to provide time series as long as possible combined with a high data quality. Due to a spatial resolution down to 50-70km and 3-hourly temporal output, they are not suitable for small scale problems (e.g., regional climate assessment, meso-scale NWP verification, input for subsequent models such as river runoff simulations). The implementation of regional reanalyses based on a limited area model along with a data assimilation scheme is able to generate reanalysis data sets with high spatio-temporal resolution. Within the Hans-Ertel-Centre for Weather Research (HErZ), the climate monitoring branch concentrates efforts on the assessment and analysis of regional climate in Germany and Europe. In joint cooperation with DWD (German Meteorological Service), a high-resolution reanalysis system based on the COSMO model has been developed. The regional reanalysis for Europe matches the domain of the CORDEX EURO-11 specifications, albeit at a higher spatial resolution, i.e., 0.055° (6km) instead of 0.11° (12km) and comprises the assimilation of observational data using the existing nudging scheme of COSMO complemented by a special soil moisture analysis with boundary conditions provided by ERA-Interim data. The reanalysis data set covers the past 20 years. Extensive evaluation of the reanalysis is performed using independent observations with special emphasis on precipitation and high-impact weather situations indicating a better representation of small scale variability. Further, the evaluation shows an added value of the regional reanalysis with respect to the forcing ERA Interim reanalysis and compared to a pure high-resolution dynamical downscaling approach without data assimilation.

SRS station 16.3: high-resolution applications

CERN Document Server

Murphy, B M; Golshan, M; Moore, M; Reid, J; Kowalski, G

2001-01-01

Station 16.3 is a high-resolution X-ray diffraction beamline at Daresbury Laboratory Synchrotron Radiation Source. The data presented demonstrate the high-resolution available on the station utilising the recently commissioned four-reflection Si 1 1 1 monochromator and three-reflection Si 1 1 1 analyser. For comparison, a reciprocal space map of the two-bounce Si 1 1 1 monochromator and two-bounce analyser is also shown. Operation of the station is illustrated with examples for silicon, and for diamond. Lattice parameter variations were measured with accuracies in the part per million range and lattice tilts at the arc second level (DuMond, Phys. Rev. 52 (1937) 872).

High-resolution X-ray crystal structure of bovine H-protein using the high-pressure cryocooling method.

Science.gov (United States)

Higashiura, Akifumi; Ohta, Kazunori; Masaki, Mika; Sato, Masaru; Inaka, Koji; Tanaka, Hiroaki; Nakagawa, Atsushi

2013-11-01

Recently, many technical improvements in macromolecular X-ray crystallography have increased the number of structures deposited in the Protein Data Bank and improved the resolution limit of protein structures. Almost all high-resolution structures have been determined using a synchrotron radiation source in conjunction with cryocooling techniques, which are required in order to minimize radiation damage. However, optimization of cryoprotectant conditions is a time-consuming and difficult step. To overcome this problem, the high-pressure cryocooling method was developed (Kim et al., 2005) and successfully applied to many protein-structure analyses. In this report, using the high-pressure cryocooling method, the X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. Structural comparisons between high- and ambient-pressure cryocooled crystals at ultra-high resolution illustrate the versatility of this technique. This is the first ultra-high-resolution X-ray structure obtained using the high-pressure cryocooling method.

Resolution-recovery-embedded image reconstruction for a high-resolution animal SPECT system.

Science.gov (United States)

Zeraatkar, Navid; Sajedi, Salar; Farahani, Mohammad Hossein; Arabi, Hossein; Sarkar, Saeed; Ghafarian, Pardis; Rahmim, Arman; Ay, Mohammad Reza

2014-11-01

The small-animal High-Resolution SPECT (HiReSPECT) is a dedicated dual-head gamma camera recently designed and developed in our laboratory for imaging of murine models. Each detector is composed of an array of 1.2 × 1.2 mm(2) (pitch) pixelated CsI(Na) crystals. Two position-sensitive photomultiplier tubes (H8500) are coupled to each head's crystal. In this paper, we report on a resolution-recovery-embedded image reconstruction code applicable to the system and present the experimental results achieved using different phantoms and mouse scans. Collimator-detector response functions (CDRFs) were measured via a pixel-driven method using capillary sources at finite distances from the head within the field of view (FOV). CDRFs were then fitted by independent Gaussian functions. Thereafter, linear interpolations were applied to the standard deviation (σ) values of the fitted Gaussians, yielding a continuous map of CDRF at varying distances from the head. A rotation-based maximum-likelihood expectation maximization (MLEM) method was used for reconstruction. A fast rotation algorithm was developed to rotate the image matrix according to the desired angle by means of pre-generated rotation maps. The experiments demonstrated improved resolution utilizing our resolution-recovery-embedded image reconstruction. While the full-width at half-maximum (FWHM) radial and tangential resolution measurements of the system were over 2 mm in nearly all positions within the FOV without resolution recovery, reaching around 2.5 mm in some locations, they fell below 1.8 mm everywhere within the FOV using the resolution-recovery algorithm. The noise performance of the system was also acceptable; the standard deviation of the average counts per voxel in the reconstructed images was 6.6% and 8.3% without and with resolution recovery, respectively. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

High-resolution electron microscopy of advanced materials

Energy Technology Data Exchange (ETDEWEB)

Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

1997-11-01

This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

High Resolution PET with 250 micrometer LSO Detectors and Adaptive Zoom

International Nuclear Information System (INIS)

Cherry, Simon R.; Qi, Jinyi

2012-01-01

There have been impressive improvements in the performance of small-animal positron emission tomography (PET) systems since their first development in the mid 1990s, both in terms of spatial resolution and sensitivity, which have directly contributed to the increasing adoption of this technology for a wide range of biomedical applications. Nonetheless, current systems still are largely dominated by the size of the scintillator elements used in the detector. Our research predicts that developing scintillator arrays with an element size of 250 (micro)m or smaller will lead to an image resolution of 500 (micro)m when using 18F- or 64Cu-labeled radiotracers, giving a factor of 4-8 improvement in volumetric resolution over the highest resolution research systems currently in existence. This proposal had two main objectives: (i) To develop and evaluate much higher resolution and efficiency scintillator arrays that can be used in the future as the basis for detectors in a small-animal PET scanner where the spatial resolution is dominated by decay and interaction physics rather than detector size. (ii) To optimize one such high resolution, high sensitivity detector and adaptively integrate it into the existing microPET II small animal PET scanner as a 'zoom-in' detector that provides higher spatial resolution and sensitivity in a limited region close to the detector face. The knowledge gained from this project will provide valuable information for building future PET systems with a complete ring of very high-resolution detector arrays and also lay the foundations for utilizing high-resolution detectors in combination with existing PET systems for localized high-resolution imaging.

Achieving High Resolution Timer Events in Virtualized Environment.

Science.gov (United States)

Adamczyk, Blazej; Chydzinski, Andrzej

2015-01-01

Virtual Machine Monitors (VMM) have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service). Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

Compact and high-resolution optical orbital angular momentum sorter

Directory of Open Access Journals (Sweden)

Chenhao Wan

2017-03-01

Full Text Available A compact and high-resolution optical orbital angular momentum (OAM sorter is proposed and demonstrated. The sorter comprises a quadratic fan-out mapper and a dual-phase corrector positioned in the pupil plane and the Fourier plane, respectively. The optical system is greatly simplified compared to previous demonstrations of OAM sorting, and the performance in resolution and efficiency is maintained. A folded configuration is set up using a single reflective spatial light modulator (SLM to demonstrate the validity of the scheme. The two phase elements are implemented on the left and right halves of the SLM and connected by a right-angle prism. Experimental results demonstrate the high resolution of the compact OAM sorter, and the current limit in efficiency can be overcome by replacing with transmissive SLMs and removing the beam splitters. This novel scheme paves the way for the miniaturization and integration of high-resolution OAM sorters.

High resolution X-ray scattering techniques for studying the sliding CDWS distortions, in NbSe sub 3

CERN Document Server

Rideau, D; Currat, R; Requardt, H; Nad, F Y; Lorenzo, J E; Brazovskii, S; Detlefs, C; Grübel, G

2001-01-01

The phase gradient in a sliding-charge density wave (CDW), which is observable as a longitudinal shift, q propor to partial deriv phi/partial deriv x, of the CDW satellite peak position, is due to the conversion free-electrons CDW-condensate, at the current electrodes. Using high resolution X-ray scattering techniques and time-resolved techniques, we monitor, on thin NbSe sub 3 whiskers, the shift, q(x), and its relaxation, q(t), upon switching off the current.

High resolution manometry findings in patients with esophageal epiphrenic diverticula.

Science.gov (United States)

Vicentine, Fernando P P; Herbella, Fernando A M; Silva, Luciana C; Patti, Marco G

2011-12-01

The pathophysiology of esophageal epiphrenic diverticula is still uncertain even though a concomitant motility disorder is found in the majority of patients in different series. High resolution manometry may allow detection of motor abnormalities in a higher number of patients with esophageal epiphrenic diverticula compared with conventional manometry. This study aims to evaluate the high resolution manometry findings in patients with esophageal epiphrenic diverticula. Nine individuals (mean age 63 ± 10 years, 4 females) with esophageal epiphrenic diverticula underwent high resolution manometry. A single diverticulum was observed in eight patients and multiple diverticula in one. Visual analysis of conventional tracings and color pressure plots for identification of segmental abnormalities was performed by two researchers experienced in high resolution manometry. Upper esophageal sphincter was normal in all patients. Esophageal body was abnormal in eight patients; lower esophageal sphincter was abnormal in seven patients. Named esophageal motility disorders were found in seven patients: achalasia in six, diffuse esophageal spasm in one. In one patient, a segmental hypercontractile zone was noticed with pressure of 196 mm Hg. High resolution manometry demonstrated motor abnormalities in all patients with esophageal epiphrenic diverticula.

Constraining Stochastic Parametrisation Schemes Using High-Resolution Model Simulations

Science.gov (United States)

Christensen, H. M.; Dawson, A.; Palmer, T.

2017-12-01

Stochastic parametrisations are used in weather and climate models as a physically motivated way to represent model error due to unresolved processes. Designing new stochastic schemes has been the target of much innovative research over the last decade. While a focus has been on developing physically motivated approaches, many successful stochastic parametrisation schemes are very simple, such as the European Centre for Medium-Range Weather Forecasts (ECMWF) multiplicative scheme `Stochastically Perturbed Parametrisation Tendencies' (SPPT). The SPPT scheme improves the skill of probabilistic weather and seasonal forecasts, and so is widely used. However, little work has focused on assessing the physical basis of the SPPT scheme. We address this matter by using high-resolution model simulations to explicitly measure the `error' in the parametrised tendency that SPPT seeks to represent. The high resolution simulations are first coarse-grained to the desired forecast model resolution before they are used to produce initial conditions and forcing data needed to drive the ECMWF Single Column Model (SCM). By comparing SCM forecast tendencies with the evolution of the high resolution model, we can measure the `error' in the forecast tendencies. In this way, we provide justification for the multiplicative nature of SPPT, and for the temporal and spatial scales of the stochastic perturbations. However, we also identify issues with the SPPT scheme. It is therefore hoped these measurements will improve both holistic and process based approaches to stochastic parametrisation. Figure caption: Instantaneous snapshot of the optimal SPPT stochastic perturbation, derived by comparing high-resolution simulations with a low resolution forecast model.

High-resolution flood modeling of urban areas using MSN_Flood

Directory of Open Access Journals (Sweden)

Michael Hartnett

2017-07-01

Full Text Available Although existing hydraulic models have been used to simulate and predict urban flooding, most of these models are inadequate due to the high spatial resolution required to simulate flows in urban floodplains. Nesting high-resolution subdomains within coarser-resolution models is an efficient solution for enabling simultaneous calculation of flooding due to tides, surges, and high river flows. MSN_Flood has been developed to incorporate moving boundaries around nested domains, permitting alternate flooding and drying along the boundary and in the interior of the domain. Ghost cells adjacent to open boundary cells convert open boundaries, in effect, into internal boundaries. The moving boundary may be multi-segmented and non-continuous, with recirculating flow across the boundary. When combined with a bespoke adaptive interpolation scheme, this approach facilitates a dynamic internal boundary. Based on an alternating-direction semi-implicit finite difference scheme, MSN_Flood was used to hindcast a major flood event in Cork City resulting from the combined pressures of fluvial, tidal, and storm surge processes. The results show that the model is computationally efficient, as the 2-m high-resolution nest is used only in the urban flooded region. Elsewhere, lower-resolution nests are used. The results also show that the model is highly accurate when compared with measured data. The model is capable of incorporating nested sub-domains when the nested boundary is multi-segmented and highly complex with lateral gradients of elevation and velocities. This is a major benefit when modelling urban floodplains at very high resolution.

Reproducible high-resolution multispectral image acquisition in dermatology

Science.gov (United States)

Duliu, Alexandru; Gardiazabal, José; Lasser, Tobias; Navab, Nassir

2015-07-01

Multispectral image acquisitions are increasingly popular in dermatology, due to their improved spectral resolution which enables better tissue discrimination. Most applications however focus on restricted regions of interest, imaging only small lesions. In this work we present and discuss an imaging framework for high-resolution multispectral imaging on large regions of interest.

High Resolution Energetic X-ray Imager (HREXI)

Science.gov (United States)

Grindlay, Jonathan

We propose to design and build the first imaging hard X-ray detector system that incorporates 3D stacking of closely packed detector readouts in finely-spaced imaging arrays with their required data processing and control electronics. In virtually all imaging astronomical detectors, detector readout is done with flex connectors or connections that are not vertical but rather horizontal , requiring loss of focal plane area. For high resolution pixel detectors needed for high speed event-based X-ray imaging, from low energy applications (CMOS) with focusing X-ray telescopes, to hard X-ray applications with pixelated CZT for large area coded aperture telescopes, this new detector development offers great promise. We propose to extend our previous and current APRA supported ProtoEXIST program that has developed the first large area imaging CZT detectors and demonstrated their astrophysical capabilities on two successful balloon flight to a next generation High Resolution Energetic X-ray Imager (HREXI), which would incorporate microvia technology for the first time to connect the readout ASIC on each CZT crystal directly to its control and data processing system. This 3-dimensional stacking of detector and readout/control system means that large area (>2m2) imaging detector planes for a High Resolution Wide-field hard X-ray telescope can be built with initially greatly reduced detector gaps and ultimately with no gaps. This increases detector area, efficiency, and simplicity of detector integration. Thus higher sensitivity wide-field imagers will be possible at lower cost. HREXI will enable a post-Swift NASA mission such as the EREXS concept proposed to PCOS to be conducted as a future MIDEX mission. This mission would conduct a high resolution (<2 arcmin) , broad band (5 200 keV) hard X-ray survey of black holes on all scales with ~10X higher sensitivity than Swift. In the current era of Time Domain Astrophysics, such a survey capability, in conjunction with a n

High-resolution investigations of edge effects in neutron imaging

International Nuclear Information System (INIS)

Strobl, M.; Kardjilov, N.; Hilger, A.; Kuehne, G.; Frei, G.; Manke, I.

2009-01-01

Edge enhancement is the main effect measured by the so-called inline or propagation-based neutron phase contrast imaging method. The effect has originally been explained by diffraction, and high spatial coherence has been claimed to be a necessary precondition. However, edge enhancement has also been found in conventional imaging with high resolution. In such cases the effects can produce artefacts and hinder quantification. In this letter the edge effects at cylindrical shaped samples and long straight edges have been studied in detail. The enhancement can be explained by refraction and total reflection. Using high-resolution imaging, where spatial resolutions better than 50 μm could be achieved, refraction and total reflection peaks - similar to diffraction patterns - could be separated and distinguished.

Ultra-high resolution AMOLED

Science.gov (United States)

Wacyk, Ihor; Prache, Olivier; Ghosh, Amal

2011-06-01

AMOLED microdisplays continue to show improvement in resolution and optical performance, enhancing their appeal for a broad range of near-eye applications such as night vision, simulation and training, situational awareness, augmented reality, medical imaging, and mobile video entertainment and gaming. eMagin's latest development of an HDTV+ resolution technology integrates an OLED pixel of 3.2 × 9.6 microns in size on a 0.18 micron CMOS backplane to deliver significant new functionality as well as the capability to implement a 1920×1200 microdisplay in a 0.86" diagonal area. In addition to the conventional matrix addressing circuitry, the HDTV+ display includes a very lowpower, low-voltage-differential-signaling (LVDS) serialized interface to minimize cable and connector size as well as electromagnetic emissions (EMI), an on-chip set of look-up-tables for digital gamma correction, and a novel pulsewidth- modulation (PWM) scheme that together with the standard analog control provides a total dimming range of 0.05cd/m2 to 2000cd/m2 in the monochrome version. The PWM function also enables an impulse drive mode of operation that significantly reduces motion artifacts in high speed scene changes. An internal 10-bit DAC ensures that a full 256 gamma-corrected gray levels are available across the entire dimming range, resulting in a measured dynamic range exceeding 20-bits. This device has been successfully tested for operation at frame rates ranging from 30Hz up to 85Hz. This paper describes the operational features and detailed optical and electrical test results for the new AMOLED WUXGA resolution microdisplay.

Generalized Nonlinear Chirp Scaling Algorithm for High-Resolution Highly Squint SAR Imaging.

Science.gov (United States)

Yi, Tianzhu; He, Zhihua; He, Feng; Dong, Zhen; Wu, Manqing

2017-11-07

This paper presents a modified approach for high-resolution, highly squint synthetic aperture radar (SAR) data processing. Several nonlinear chirp scaling (NLCS) algorithms have been proposed to solve the azimuth variance of the frequency modulation rates that are caused by the linear range walk correction (LRWC). However, the azimuth depth of focusing (ADOF) is not handled well by these algorithms. The generalized nonlinear chirp scaling (GNLCS) algorithm that is proposed in this paper uses the method of series reverse (MSR) to improve the ADOF and focusing precision. It also introduces a high order processing kernel to avoid the range block processing. Simulation results show that the GNLCS algorithm can enlarge the ADOF and focusing precision for high-resolution highly squint SAR data.

Generalized Nonlinear Chirp Scaling Algorithm for High-Resolution Highly Squint SAR Imaging

Directory of Open Access Journals (Sweden)

Tianzhu Yi

2017-11-01

Full Text Available This paper presents a modified approach for high-resolution, highly squint synthetic aperture radar (SAR data processing. Several nonlinear chirp scaling (NLCS algorithms have been proposed to solve the azimuth variance of the frequency modulation rates that are caused by the linear range walk correction (LRWC. However, the azimuth depth of focusing (ADOF is not handled well by these algorithms. The generalized nonlinear chirp scaling (GNLCS algorithm that is proposed in this paper uses the method of series reverse (MSR to improve the ADOF and focusing precision. It also introduces a high order processing kernel to avoid the range block processing. Simulation results show that the GNLCS algorithm can enlarge the ADOF and focusing precision for high-resolution highly squint SAR data.

MEASURING THE UNDETECTABLE: PROPER MOTIONS AND PARALLAXES OF VERY FAINT SOURCES

International Nuclear Information System (INIS)

Lang, Dustin; Hogg, David W.; Jester, Sebastian; Rix, Hans-Walter

2009-01-01

The near future of astrophysics involves many large solid-angle, multi-epoch, multiband imaging surveys. These surveys will, at their faint limits, have data on a large number of sources that are too faint to be detected at any individual epoch. Here, we show that it is possible to measure in multi-epoch data not only the fluxes and positions, but also the parallaxes and proper motions of sources that are too faint to be detected at any individual epoch. The method involves fitting a model of a moving point source simultaneously to all imaging, taking account of the noise and point-spread function (PSF) in each image. By this method it is possible to measure the proper motion of a point source with an uncertainty close to the minimum possible uncertainty given the information in the data, which is limited by the PSF, the distribution of observation times (epochs), and the total signal-to-noise in the combined data. We demonstrate our technique on multi-epoch Sloan Digital Sky Survey (SDSS) imaging of the SDSS Southern Stripe (SDSSSS). We show that with our new technique we can use proper motions to distinguish very red brown dwarfs from very high-redshift quasars in these SDSS data, for objects that are inaccessible to traditional techniques, and with better fidelity than by multiband imaging alone. We rediscover all 10 known brown dwarfs in our sample and present nine new candidate brown dwarfs, identified on the basis of significant proper motion.

Human enamel structure studied by high resolution electron microscopy

International Nuclear Information System (INIS)

Wen, S.L.

1989-01-01

Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

HIGH-RESOLUTION RADIO OBSERVATIONS OF THE REMNANT OF SN 1987A AT HIGH FREQUENCIES

International Nuclear Information System (INIS)

Zanardo, Giovanna; Staveley-Smith, L.; Potter, T. M.; Ng, C.-Y.; Gaensler, B. M.; Manchester, R. N.; Tzioumis, A. K.

2013-01-01

We present new imaging observations of the remnant of Supernova (SN) 1987A at 44 GHz, performed in 2011 with the Australia Telescope Compact Array (ATCA). The 0.''35 × 0.''23 resolution of the diffraction-limited image is the highest achieved to date in high-dynamic range. We also present a new ATCA image at 18 GHz derived from 2011 observations, which is super-resolved to 0.''25. The flux density is 40 ± 2 mJy at 44 GHz and 81 ± 6 mJy at 18 GHz. At both frequencies, the remnant exhibits a ring-like emission with two prominent lobes, and an east-west brightness asymmetry that peaks on the eastern lobe. A central feature of fainter emission appears at 44 GHz. A comparison with previous ATCA observations at 18 and 36 GHz highlights higher expansion velocities of the remnant's eastern side. The 18-44 GHz spectral index is α = –0.80 (S ν ∝ν α ). The spectral index map suggests slightly steeper values at the brightest sites on the eastern lobe, whereas flatter values are associated with the inner regions. The remnant morphology at 44 GHz generally matches the structure seen with contemporaneous X-ray and Hα observations. Unlike the Hα emission, both the radio and X-ray emission peaks on the eastern lobe. The regions of flatter spectral index align and partially overlap with the optically visible ejecta. Simple free-free absorption models suggest that emission from a pulsar wind nebula or a compact source inside the remnant may now be detectable at high frequencies or at low frequencies if there are holes in the ionized component of the ejecta.

High resolution backscattering instruments

International Nuclear Information System (INIS)

Coldea, R.

2001-01-01

The principle of operation of indirect-geometry time-of-flight spectrometers are presented, including the IRIS at the ISIS spallation neutron source. The key features that make those types of spectrometers ideally suited for low-energy spectroscopy are: high energy resolution over a wide dynamic range, and simultaneous measurement over a large momentum transfer range provided by the wide angular detector coverage. To exemplify these features are discussed of single-crystal experiments of the spin dynamics in the two-dimensional frustrated quantum magnet Cs 2 CuCl 4 . (R.P.)

Parameter-free extraction of EMCD from an energy-filtered diffraction datacube using multivariate curve resolution

International Nuclear Information System (INIS)

Muto, S.; Tatsumi, K.; Rusz, J.

2013-01-01

We present a parameter-free method of extraction of the electron magnetic circular dichroism spectra from energy-filtered diffraction patterns measured on a crystalline specimen. The method is based on a multivariate curve resolution technique. The main advantage of the proposed method is that it allows extraction of the magnetic signal regardless of the symmetry and orientation of the crystal, as long as there is a sufficiently strong magnetic component of the signal in the diffraction plane. This method essentially overcomes difficulties in extraction of the EMCD signal caused by complexity of dynamical diffraction effects. - Highlights: ► New method of extraction of EMCD signal using statistical methods (multivariate curve resolution). ► EMCD can be extracted quantitatively regardless of symmetry of crystal or its orientation. ► First principles simulation of EFDIF datacube, including dynamical diffraction effects

Using Adobe Acrobat to create high-resolution line art images.

Science.gov (United States)

Woo, Hyoun Sik; Lee, Jeong Min

2009-08-01

The purpose of this article is to introduce a method for using Adobe Acrobat to make high-resolution and high-quality line art images. High-resolution and high-quality line art images for radiology journal submission can be generated using Adobe Acrobat as a steppingstone, and the customized PDF conversion settings can be used for converting hybrid images, including both bitmap and vector components.

High-resolution axial MR imaging of tibial stress injuries

Directory of Open Access Journals (Sweden)

Mammoto Takeo

2012-05-01

Full Text Available Abstract Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries.

High-resolution axial MR imaging of tibial stress injuries

Science.gov (United States)

2012-01-01

Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries. PMID:22574840

High-resolution esophageal pressure topography for esophageal motility disorders

OpenAIRE

Hashem Fakhre Yaseri; Gholamreza Hamsi; Tayeb Ramim

2016-01-01

Background: High-resolution manometer (HRM) of the esophagus has become the main diagnostic test in the evaluation of esophageal motility disorders. The development of high-resolution manometry catheters and software displays of manometry recordings in color-coded pressure plots have changed the diagnostic assessment of esophageal disease. The first step of the Chicago classification described abnormal esophagogastric junction deglutitive relaxation. The latest classification system, proposed...

Quantitation of Acrylamide in Foods by High-Resolution Mass Spectrometry

NARCIS (Netherlands)

Troise, A.D.; Fogliano, Vincenzo

2016-01-01

The use of liquid chromatography high-resolution mass spectrometry (LC-HRMS) and direct analysis real-time high-resolution mass spectrometry (DART-HRMS) defines a new scenario in the analysis of thermal-induced toxicants, such as acrylamide. Several factors contribute to the definition of the

Fast generation of Fresnel holograms based on multirate filtering.

Science.gov (United States)

Tsang, Peter; Liu, Jung-Ping; Cheung, Wai-Keung; Poon, Ting-Chung

2009-12-01

One of the major problems in computer-generated holography is the high computation cost involved for the calculation of fringe patterns. Recently, the problem has been addressed by imposing a horizontal parallax only constraint whereby the process can be simplified to the computation of one-dimensional sublines, each representing a scan plane of the object scene. Subsequently the sublines can be expanded to a two-dimensional hologram through multiplication with a reference signal. Furthermore, economical hardware is available with which sublines can be generated in a computationally free manner with high throughput of approximately 100 M pixels/second. Apart from decreasing the computation loading, the sublines can be treated as intermediate data that can be compressed by simply downsampling the number of sublines. Despite these favorable features, the method is suitable only for the generation of white light (rainbow) holograms, and the resolution of the reconstructed image is inferior to the classical Fresnel hologram. We propose to generate holograms from one-dimensional sublines so that the above-mentioned problems can be alleviated. However, such an approach also leads to a substantial increase in computation loading. To overcome this problem we encapsulated the conversion of sublines to holograms as a multirate filtering process and implemented the latter by use of a fast Fourier transform. Evaluation reveals that, for holograms of moderate size, our method is capable of operating 40,000 times faster than the calculation of Fresnel holograms based on the precomputed table lookup method. Although there is no relative vertical parallax between object points at different distance planes, a global vertical parallax is preserved for the object scene as a whole and the reconstructed image can be observed easily.

High-spin research with HERA [High Energy-Resolution Array

International Nuclear Information System (INIS)

Diamond, R.M.

1987-06-01

The topic of this report is high spin research with the High Energy Resolution Array (HERA) at Lawrence Berkeley Laboratory. This is a 21 Ge detector system, the first with bismuth germanate (BGO) Compton suppression. The array is described briefly and some of the results obtained during the past year using this detector facility are discussed. Two types of studies are described: observation of superdeformation in the light Nd isotopes, and rotational damping at high spin and excitation energy in the continuum gamma ray spectrum

Ultra high resolution soft x-ray tomography

International Nuclear Information System (INIS)

Haddad, W.S.; Trebes, J.E.; Goodman, D.M.

1995-01-01

Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were separated by ∼5μm. A series of nine 2-D images of the object were recorded at angles between -50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3-D image by means of an algebraic reconstruction technique (ART) algorithm. A transverse resolution of ∼1000 Angstrom was observed. Artifacts in the reconstruction limited the overall depth resolution to ∼6000 Angstrom, however some features were clearly reconstructed with a depth resolution of ∼1000 Angstrom. A specially modified ART algorithm and a constrained conjugate gradient (CCG) code were also developed as improvements over the standard ART algorithm. Both of these methods made significant improvements in the overall depth resolution bringing it down to ∼1200 Angstrom overall. Preliminary projection data sets were also recorded with both dry and re-hydrated human sperm cells over a similar angular range

Ultra high resolution soft x-ray tomography

International Nuclear Information System (INIS)

Haddad, W.S.; Trebes, J.E.; Goodman, D.M.; Lee, H.R.; McNulty, I.; Zalensky, A.O.

1995-01-01

Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were separated by ∼5 microm. A series of nine 2-D images of the object were recorded at angles between -50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3-D image by means of an algebraic reconstruction technique (ART) algorithm. A transverse resolution of ∼ 1,000 angstrom was observed. Artifacts in the reconstruction limited the overall depth resolution to ∼ 6,000 angstrom, however some features were clearly reconstructed with a depth resolution of ∼ 1,000 angstrom. A specially modified ART algorithm and a constrained conjugate gradient (CCG) code were also developed as improvements over the standard ART algorithm. Both of these methods made significant improvements in the overall depth resolution, bringing it down to ∼ 1,200 angstrom overall. Preliminary projection data sets were also recorded with both dry and re-hydrated human sperm cells over a similar angular range

High-resolution 3D imaging of polymerized photonic crystals by lab-based x-ray nanotomography with 50-nm resolution

Science.gov (United States)

Yin, Leilei; Chen, Ying-Chieh; Gelb, Jeff; Stevenson, Darren M.; Braun, Paul A.

2010-09-01

High resolution x-ray computed tomography is a powerful non-destructive 3-D imaging method. It can offer superior resolution on objects that are opaque or low contrast for optical microscopy. Synchrotron based x-ray computed tomography systems have been available for scientific research, but remain difficult to access for broader users. This work introduces a lab-based high-resolution x-ray nanotomography system with 50nm resolution in absorption and Zernike phase contrast modes. Using this system, we have demonstrated high quality 3-D images of polymerized photonic crystals which have been analyzed for band gap structures. The isotropic volumetric data shows excellent consistency with other characterization results.

High-resolution nuclear magnetic resonance studies of proteins.

Science.gov (United States)

Jonas, Jiri

2002-03-25

The combination of advanced high-resolution nuclear magnetic resonance (NMR) techniques with high-pressure capability represents a powerful experimental tool in studies of protein folding. This review is organized as follows: after a general introduction of high-pressure, high-resolution NMR spectroscopy of proteins, the experimental part deals with instrumentation. The main section of the review is devoted to NMR studies of reversible pressure unfolding of proteins with special emphasis on pressure-assisted cold denaturation and the detection of folding intermediates. Recent studies investigating local perturbations in proteins and the experiments following the effects of point mutations on pressure stability of proteins are also discussed. Ribonuclease A, lysozyme, ubiquitin, apomyoglobin, alpha-lactalbumin and troponin C were the model proteins investigated.

High-resolution CT of the lungs: Anatomic-pathologic correlation

International Nuclear Information System (INIS)

Stein, M.G.; Webb, W.R.; Finkbeiner, W.; Gamsu, G.

1986-01-01

The interpretation of thin-section (1.5-mm), high-resolution CT scans of the lungs has been limited by lack of direct radiologic and pathologic correlation. The author scanned fresh inflated isolated lungs from ten healthy and five diseased subjects using thin-section, high-resolution techniques. The lungs were then fixed by inflation with endobronchial Formalin. Gough sections (1 mm thick) were obtained at the same levels as the CT scans. In healthy subjects, secondary lobules were identified by the presence of visible interlobular septa and central arterioles. In some patients with disease, septal thickening was visible. In patients with honeycombing cystic areas of destroyed lung were seen, along with areas of fibrosis. Emphysema was well evaluated. Thin-section, high-resolution CT can define lung architecture and may resolve mild changes of the interstitium

High-resolution x-ray imaging using a structured scintillator

Energy Technology Data Exchange (ETDEWEB)

Hormozan, Yashar, E-mail: hormozan@kth.se; Sychugov, Ilya; Linnros, Jan [Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, Kista, Stockholm SE-16440 (Sweden)

2016-02-15

Purpose: In this study, the authors introduce a new generation of finely structured scintillators with a very high spatial resolution (a few micrometers) compared to conventional scintillators, yet maintaining a thick absorbing layer for improved detectivity. Methods: Their concept is based on a 2D array of high aspect ratio pores which are fabricated by ICP etching, with spacings (pitches) of a few micrometers, on silicon and oxidation of the pore walls. The pores were subsequently filled by melting of powdered CsI(Tl), as the scintillating agent. In order to couple the secondary emitted photons of the back of the scintillator array to a CCD device, having a larger pixel size than the pore pitch, an open optical microscope with adjustable magnification was designed and implemented. By imaging a sharp edge, the authors were able to calculate the modulation transfer function (MTF) of this finely structured scintillator. Results: The x-ray images of individually resolved pores suggest that they have been almost uniformly filled, and the MTF measurements show the feasibility of a few microns spatial resolution imaging, as set by the scintillator pore size. Compared to existing techniques utilizing CsI needles as a structured scintillator, their results imply an almost sevenfold improvement in resolution. Finally, high resolution images, taken by their detector, are presented. Conclusions: The presented work successfully shows the functionality of their detector concept for high resolution imaging and further fabrication developments are most likely to result in higher quantum efficiencies.

Science with High Spatial Resolution Far-Infrared Data

Science.gov (United States)

Terebey, Susan (Editor); Mazzarella, Joseph M. (Editor)

1994-01-01

The goal of this workshop was to discuss new science and techniques relevant to high spatial resolution processing of far-infrared data, with particular focus on high resolution processing of IRAS data. Users of the maximum correlation method, maximum entropy, and other resolution enhancement algorithms applicable to far-infrared data gathered at the Infrared Processing and Analysis Center (IPAC) for two days in June 1993 to compare techniques and discuss new results. During a special session on the third day, interested astronomers were introduced to IRAS HIRES processing, which is IPAC's implementation of the maximum correlation method to the IRAS data. Topics discussed during the workshop included: (1) image reconstruction; (2) random noise; (3) imagery; (4) interacting galaxies; (5) spiral galaxies; (6) galactic dust and elliptical galaxies; (7) star formation in Seyfert galaxies; (8) wavelet analysis; and (9) supernova remnants.

High-resolution magnetic resonance imaging reveals nuclei of the human amygdala: manual segmentation to automatic atlas

DEFF Research Database (Denmark)

Saygin, Z M; Kliemann, D; Iglesias, J. E.

2017-01-01

The amygdala is composed of multiple nuclei with unique functions and connections in the limbic system and to the rest of the brain. However, standard in vivo neuroimaging tools to automatically delineate the amygdala into its multiple nuclei are still rare. By scanning postmortem specimens at high...... resolution (100-150µm) at 7T field strength (n = 10), we were able to visualize and label nine amygdala nuclei (anterior amygdaloid, cortico-amygdaloid transition area; basal, lateral, accessory basal, central, cortical medial, paralaminar nuclei). We created an atlas from these labels using a recently...... developed atlas building algorithm based on Bayesian inference. This atlas, which will be released as part of FreeSurfer, can be used to automatically segment nine amygdala nuclei from a standard resolution structural MR image. We applied this atlas to two publicly available datasets (ADNI and ABIDE...

Textural Segmentation of High-Resolution Sidescan Sonar Images

National Research Council Canada - National Science Library

Kalcic, Maria; Bibee, Dale

1995-01-01

.... The high resolution of the 455 kHz sonar imagery also provides much information about the surficial bottom sediments, however their acoustic scattering properties are not well understood at high frequencies...

High-resolution computed tomography findings in pulmonary Langerhans cell histiocytosis

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Rosana Souza [Universidade Federal do Rio de Janeiro (HUCFF/UFRJ), RJ (Brazil). Hospital Universitario Clementino Fraga Filho. Unit of Radiology; Capone, Domenico; Ferreira Neto, Armando Leao [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

2011-07-15

Objective: The present study was aimed at characterizing main lung changes observed in pulmonary Langerhans cell histiocytosis by means of high-resolution computed tomography. Materials and Methods: High-resolution computed tomography findings in eight patients with proven disease diagnosed by open lung biopsy, immunohistochemistry studies and/or extrapulmonary manifestations were retrospectively evaluated. Results: Small rounded, thin-walled cystic lesions were observed in the lung of all the patients. Nodules with predominantly peripheral distribution over the lung parenchyma were observed in 75% of the patients. The lesions were diffusely distributed, predominantly in the upper and middle lung fields in all of the cases, but involvement of costophrenic angles was observed in 25% of the patients. Conclusion: Comparative analysis of high-resolution computed tomography and chest radiography findings demonstrated that thinwalled cysts and small nodules cannot be satisfactorily evaluated by conventional radiography. Because of its capacity to detect and characterize lung cysts and nodules, high-resolution computed tomography increases the probability of diagnosing pulmonary Langerhans cell histiocytosis. (author)

High-Temperature Lead-Free Solder Alternatives: Possibilities and Properties

DEFF Research Database (Denmark)

High-temperature solders have been widely used as joining materials to provide stable interconnections that resist a severe thermal environment and also to facilitate the drive for miniaturization. High-lead containing solders have been commonly used as high-temperature solders. The development...... of high-temperature lead-free solders has become an important issue for both the electronics and automobile industries because of the health and environmental concerns associated with lead usage. Unfortunately, limited choices are available as high-temperature lead-free solders. This work outlines...... the criteria for the evaluation of a new high-temperature lead-free solder material. A list of potential ternary high-temperature lead-free solder alternatives based on the Au-Sn and Au-Ge systems is proposed. Furthermore, a comprehensive comparison of the high-temperature stability of microstructures...

A Forward-Looking High-Resolution GPR System

National Research Council Canada - National Science Library

Kositsky, Joel; Milanfar, Peyman

1999-01-01

A high-resolution ground penetrating radar (GPR) system was designed to help define the optimal radar parameters needed for the efficient standoff detection of buried and surface-laid antitank mines...

Advances in Computational High-Resolution Mechanical Spectroscopy HRMS Part I: Logarithmic Decrement

International Nuclear Information System (INIS)

Majewski, M; Magalas, L B; Piłat, A

2012-01-01

The comparison between different methods used to compute the logarithmic decrement in high-resolution mechanical spectroscopy (HRMS) is analyzed. The performance of parametric OMI method (Optimization in Multiple Intervals) and interpolated discrete Fourier transform (IpDFT) methods are investigated as a function of the sampling frequency used to digitize free decaying oscillations in low-frequency resonant mechanical spectrometers. It is clearly demonstrated that a new Yoshida-Magalas (YM) method is the most powerful IpDFT-based method which outperforms the standard Yoshida (Y) method and other DFT-based methods. Four IpDFT methods and the OMI method are carefully analyzed as a function of the sampling frequency. The results presented in this work clearly show that the relative error in the estimation of the logarithmic decrement depends both on the length of free decaying signal and on the sampling frequency. The effect of the sampling frequency was not yet reported in the literature. The performance of different methods used in the computations of the logarithmic decrement can be listed in the following order: (1) the OMI, (2) the Yoshida-Magalas YM, (3) the Yoshida-Magalas YMC, and finally (4) the Yoshida Y.

Accelerated high-resolution photoacoustic tomography via compressed sensing

Science.gov (United States)

Arridge, Simon; Beard, Paul; Betcke, Marta; Cox, Ben; Huynh, Nam; Lucka, Felix; Ogunlade, Olumide; Zhang, Edward

2016-12-01

Current 3D photoacoustic tomography (PAT) systems offer either high image quality or high frame rates but are not able to deliver high spatial and temporal resolution simultaneously, which limits their ability to image dynamic processes in living tissue (4D PAT). A particular example is the planar Fabry-Pérot (FP) photoacoustic scanner, which yields high-resolution 3D images but takes several minutes to sequentially map the incident photoacoustic field on the 2D sensor plane, point-by-point. However, as the spatio-temporal complexity of many absorbing tissue structures is rather low, the data recorded in such a conventional, regularly sampled fashion is often highly redundant. We demonstrate that combining model-based, variational image reconstruction methods using spatial sparsity constraints with the development of novel PAT acquisition systems capable of sub-sampling the acoustic wave field can dramatically increase the acquisition speed while maintaining a good spatial resolution: first, we describe and model two general spatial sub-sampling schemes. Then, we discuss how to implement them using the FP interferometer and demonstrate the potential of these novel compressed sensing PAT devices through simulated data from a realistic numerical phantom and through measured data from a dynamic experimental phantom as well as from in vivo experiments. Our results show that images with good spatial resolution and contrast can be obtained from highly sub-sampled PAT data if variational image reconstruction techniques that describe the tissues structures with suitable sparsity-constraints are used. In particular, we examine the use of total variation (TV) regularization enhanced by Bregman iterations. These novel reconstruction strategies offer new opportunities to dramatically increase the acquisition speed of photoacoustic scanners that employ point-by-point sequential scanning as well as reducing the channel count of parallelized schemes that use detector arrays.

A Very High Spatial Resolution Detector for Small Animal PET

International Nuclear Information System (INIS)

Kanai Shah, M.S.

2007-01-01

Positron Emission Tomography (PET) is an in vivo analog of autoradiography and has the potential to become a powerful new tool in imaging biological processes in small laboratory animals. PET imaging of small animals can provide unique information that can help in advancement of human disease models as well as drug development. Clinical PET scanners used for human imaging are bulky, expensive and do not have adequate spatial resolution for small animal studies. Hence, dedicated, low cost instruments are required for conducting small animal studies with higher spatial resolution than what is currently achieved with clinical as well as dedicated small animal PET scanners. The goal of the proposed project is to investigate a new all solid-state detector design for small animal PET imaging. Exceptionally high spatial resolution, good timing resolution, and excellent energy resolution are expected from the proposed detector design. The Phase I project was aimed at demonstrating the feasibility of producing high performance solid-state detectors that provide high sensitivity, spatial resolution, and timing characteristics. Energy resolution characteristics of the new detector were also investigated. The goal of the Phase II project is to advance the promising solid-state detector technology for small animal PET and determine its full potential. Detectors modules will be built and characterized and finally, a bench-top small animal PET system will be assembled and evaluated

Strengthening IAEA safeguards using high-resolution commercial satellite imagery

International Nuclear Information System (INIS)

Zhang Hui

2001-01-01

Full text: In May 1997, the IAEA Board of Governors adopted the Additional Safeguards Protocol to improve its ability to detect the undeclared production of fissile material. This new strengthened safeguards system has opened the door for the IAEA to use of all types of information, including the potential use of commercial satellite imagery. We have therefore been investigating the feasibility of strengthening IAEA safeguards using commercial satellite imagery. Based on our analysis on a number of one-meter resolution IKONOS satellite images of military nuclear production facilities at nuclear states including Russia, China, India, Pakistan and Israel, we found that the new high-resolution commercial satellite imagery would play a new and valuable role in strengthening IAEA safeguards. Since 1999, images with a resolution of one meter have been available commercially from Space Imaging's IKONOS satellite. One-meter images from other companies are expected to enter the market soon. Although still an order of magnitude less capable than military imaging satellites, the capabilities of these new high-resolution commercial satellites are good enough to detect and identify the major visible characteristics of nuclear production facilities and sites. Unlike the classified spy satellite photos limited to few countries, the commercial satellite imagery is commercially available to anyone who wants to purchase it. Therefore, the new commercial satellite open a new chance that each state, international organizations, and non-governmental groups could use the commercial images to play a more proactive role in monitoring the nuclear activities in related countries and verifying the compliance of non-proliferation agreements. This could help galvanize support for intensified efforts to slow the pace of nuclear proliferation. To produce fissile materials (plutonium and highly enriched uranium) for weapons, a country would operate dedicated plutonium-production reactors and the

Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions

Directory of Open Access Journals (Sweden)

K. Yu

2016-04-01

Full Text Available Formation of ozone and organic aerosol in continental atmospheres depends on whether isoprene emitted by vegetation is oxidized by the high-NOx pathway (where peroxy radicals react with NO or by low-NOx pathways (where peroxy radicals react by alternate channels, mostly with HO2. We used mixed layer observations from the SEAC4RS aircraft campaign over the Southeast US to test the ability of the GEOS-Chem chemical transport model at different grid resolutions (0.25°  ×  0.3125°, 2°  ×  2.5°, 4°  ×  5° to simulate this chemistry under high-isoprene, variable-NOx conditions. Observations of isoprene and NOx over the Southeast US show a negative correlation, reflecting the spatial segregation of emissions; this negative correlation is captured in the model at 0.25°  ×  0.3125° resolution but not at coarser resolutions. As a result, less isoprene oxidation takes place by the high-NOx pathway in the model at 0.25°  ×  0.3125° resolution (54 % than at coarser resolution (59 %. The cumulative probability distribution functions (CDFs of NOx, isoprene, and ozone concentrations show little difference across model resolutions and good agreement with observations, while formaldehyde is overestimated at coarse resolution because excessive isoprene oxidation takes place by the high-NOx pathway with high formaldehyde yield. The good agreement of simulated and observed concentration variances implies that smaller-scale non-linearities (urban and power plant plumes are not important on the regional scale. Correlations of simulated vs. observed concentrations do not improve with grid resolution because finer modes of variability are intrinsically more difficult to capture. Higher model resolution leads to decreased conversion of NOx to organic nitrates and increased conversion to nitric acid, with total reactive nitrogen oxides (NOy changing little across model resolutions. Model concentrations in the

Processing method for high resolution monochromator

International Nuclear Information System (INIS)

Kiriyama, Koji; Mitsui, Takaya

2006-12-01

A processing method for high resolution monochromator (HRM) has been developed at Japanese Atomic Energy Agency/Quantum Beam Science Directorate/Synchrotron Radiation Research unit at SPring-8. For manufacturing a HRM, a sophisticated slicing machine and X-ray diffractometer have been installed for shaping a crystal ingot and orienting precisely the surface of a crystal ingot, respectively. The specification of the slicing machine is following; Maximum size of a diamond blade is φ 350mm in diameter, φ 38.1mm in the spindle diameter, and 2mm in thickness. A large crystal such as an ingot with 100mm in diameter, 200mm in length can be cut. Thin crystal samples such as a wafer can be also cut using by another sample holder. Working distance of a main shaft with the direction perpendicular to working table in the machine is 350mm at maximum. Smallest resolution of the main shaft with directions of front-and-back and top-and-bottom are 0.001mm read by a digital encoder. 2mm/min can set for cutting samples in the forward direction. For orienting crystal faces relative to the blade direction adjustment, a one-circle goniometer and 2-circle segment are equipped on the working table in the machine. A rotation and a tilt of the stage can be done by manual operation. Digital encoder in a turn stage is furnished and has angle resolution of less than 0.01 degrees. In addition, a hand drill as a supporting device for detailed processing of crystal is prepared. Then, an ideal crystal face can be cut from crystal samples within an accuracy of about 0.01 degrees. By installation of these devices, a high energy resolution monochromator crystal for inelastic x-ray scattering and a beam collimator are got in hand and are expected to be used for nanotechnology studies. (author)

High-resolution coded-aperture design for compressive X-ray tomography using low resolution detectors

Science.gov (United States)

Mojica, Edson; Pertuz, Said; Arguello, Henry

2017-12-01

One of the main challenges in Computed Tomography (CT) is obtaining accurate reconstructions of the imaged object while keeping a low radiation dose in the acquisition process. In order to solve this problem, several researchers have proposed the use of compressed sensing for reducing the amount of measurements required to perform CT. This paper tackles the problem of designing high-resolution coded apertures for compressed sensing computed tomography. In contrast to previous approaches, we aim at designing apertures to be used with low-resolution detectors in order to achieve super-resolution. The proposed method iteratively improves random coded apertures using a gradient descent algorithm subject to constraints in the coherence and homogeneity of the compressive sensing matrix induced by the coded aperture. Experiments with different test sets show consistent results for different transmittances, number of shots and super-resolution factors.

Towards high resolution polarisation analysis using double polarisation and ellipsoidal analysers

CERN Document Server

Martin-Y-Marero, D

2002-01-01

Classical polarisation analysis methods lack the combination of high resolution and high count rate necessary to cope with the demand of modern condensed-matter experiments. In this work, we present a method to achieve high resolution polarisation analysis based on a double polarisation system. Coupling this method with an ellipsoidal wavelength analyser, a high count rate can be achieved whilst delivering a resolution of around 10 mu eV. This method is ideally suited to pulsed sources, although it can be adapted to continuous sources as well. (orig.)

A robust object-based shadow detection method for cloud-free high resolution satellite images over urban areas and water bodies

Science.gov (United States)

Tatar, Nurollah; Saadatseresht, Mohammad; Arefi, Hossein; Hadavand, Ahmad

2018-06-01

Unwanted contrast in high resolution satellite images such as shadow areas directly affects the result of further processing in urban remote sensing images. Detecting and finding the precise position of shadows is critical in different remote sensing processing chains such as change detection, image classification and digital elevation model generation from stereo images. The spectral similarity between shadow areas, water bodies, and some dark asphalt roads makes the development of robust shadow detection algorithms challenging. In addition, most of the existing methods work on pixel-level and neglect the contextual information contained in neighboring pixels. In this paper, a new object-based shadow detection framework is introduced. In the proposed method a pixel-level shadow mask is built by extending established thresholding methods with a new C4 index which enables to solve the ambiguity of shadow and water bodies. Then the pixel-based results are further processed in an object-based majority analysis to detect the final shadow objects. Four different high resolution satellite images are used to validate this new approach. The result shows the superiority of the proposed method over some state-of-the-art shadow detection method with an average of 96% in F-measure.

Coastal and Inland Water Applications of High Resolution Optical Satellite Data from Landsat-8 and Sentinel-2

Science.gov (United States)

Vanhellemont, Q.

2016-02-01

Since the launch of Landsat-8 (L8) in 2013, a joint NASA/USGS programme, new applications of high resolution imagery for coastal and inland waters have become apparent. The optical imaging instrument on L8, the Operational Land Imager (OLI), is much improved compared to its predecessors on L5 and L7, especially with regards to SNR and digitization, and is therefore well suited for retrieving water reflectances and derived parameters such as turbidity and suspended sediment concentration. In June 2015, the European Space Agency (ESA) successfully launched a similar instrument, the MultiSpectral Imager (MSI), on board of Sentinel-2A (S2A). Imagery from both L8 and S2A are free of charge and publicly available (S2A starting at the end of 2015). Atmospheric correction schemes and processing software is under development in the EC-FP7 HIGHROC project. The spatial resolution of these instruments (10-60 m) is a great improvement over typical moderate resolution ocean colour sensors such as MODIS and MERIS (0.25 - 1 km). At higher resolution, many more lakes, rivers, ports and estuaries are spatially resolved, and can thus now be studied using satellite data, unlocking potential for mandatory monitoring e.g. under European Directives such as the Marine Strategy Framework Directive and the Water Framework Directive. We present new applications of these high resolution data, such as monitoring of offshore constructions, wind farms, sediment transport, dredging and dumping, shipping and fishing activities. The spatial variability at sub moderate resolution (0.25 - 1 km) scales can be assessed, as well as the impact of sub grid scale variability (including ships and platforms used for validation) on the moderate pixel retrieval. While the daily revisit time of the moderate resolution sensors is vastly superior to those of the high resolution satellites, at the equator respectively 16 and 10 days for L8 and S2A, the low revisit times can be partially mitigated by combining data

Demonstration of a large-size horizontal light-field display based on the LED panel and the micro-pinhole unit array

Science.gov (United States)

Yang, Le; Sang, Xinzhu; Yu, Xunbo; Liu, Boyang; Liu, Li; Yang, Shenwu; Yan, Binbin; Du, Jingyan; Gao, Chao

2018-05-01

A 54-inch horizontal-parallax only light-field display based on the light-emitting diode (LED) panel and the micro-pinhole unit array (MPUA) is demonstrated. Normally, the perceived 3D effect of the three-dimensional (3D) display with smooth motion parallax and abundant light-field information can be enhanced with increasing the density of viewpoints. However, the density of viewpoints is inversely proportional to the spatial display resolution for the conventional integral imaging. Here, a special MPUA is designed and fabricated, and the displayed 3D scene constructed by the proposed horizontal light-field display is presented. Compared with the conventional integral imaging, both the density of horizontal viewpoints and the spatial display resolution are significantly improved. In the experiment, A 54-inch horizontal light-field display with 42.8° viewing angle based on the LED panel with the resolution of 1280 × 720 and the MPUA is realized, which can provide natural 3D visual effect to observers with high quality.

Ultra-high resolution HLA genotyping and allele discovery by highly multiplexed cDNA amplicon pyrosequencing

Directory of Open Access Journals (Sweden)

Lank Simon M

2012-08-01

Full Text Available Abstract Background High-resolution HLA genotyping is a critical diagnostic and research assay. Current methods rarely achieve unambiguous high-resolution typing without making population-specific frequency inferences due to a lack of locus coverage and difficulty in exon-phase matching. Achieving high-resolution typing is also becoming more challenging with traditional methods as the database of known HLA alleles increases. Results We designed a cDNA amplicon-based pyrosequencing method to capture 94% of the HLA class I open-reading-frame with only two amplicons per sample, and an analogous method for class II HLA genes, with a primary focus on sequencing the DRB loci. We present a novel Galaxy server-based analysis workflow for determining genotype. During assay validation, we performed two GS Junior sequencing runs to determine the accuracy of the HLA class I amplicons and DRB amplicon at different levels of multiplexing. When 116 amplicons were multiplexed, we unambiguously resolved 99%of class I alleles to four- or six-digit resolution, as well as 100% unambiguous DRB calls. The second experiment, with 271 multiplexed amplicons, missed some alleles, but generated high-resolution, concordant typing for 93% of class I alleles, and 96% for DRB1 alleles. In a third, preliminary experiment we attempted to sequence novel amplicons for other class II loci with mixed success. Conclusions The presented assay is higher-throughput and higher-resolution than existing HLA genotyping methods, and suitable for allele discovery or large cohort sampling. The validated class I and DRB primers successfully generated unambiguously high-resolution genotypes, while further work is needed to validate additional class II genotyping amplicons.

Transistor reset preamplifier for high-rate high-resolution spectroscopy

International Nuclear Information System (INIS)

Landis, D.A.; Cork, C.P.; Madden, N.W.; Goulding, F.S.

1981-10-01

Pulsed transistor reset of high resolution charge sensitive preamplifiers used in cooled semiconductor spectrometers can sometimes have an advantage over pulsed light reset systems. Several versions of transistor reset spectrometers using both silicon and germanium detectors have been built. This paper discusses the advantages of the transistor reset system and illustrates several configurations of the packages used for the FET and reset transistor. It also describes the preamplifer circuit and shows the performance of the spectrometer at high rates

Constructing a WISE High Resolution Galaxy Atlas

Science.gov (United States)

Jarrett, T. H.; Masci, F.; Tsai, C. W.; Petty, S.; Cluver, M.; Assef, Roberto J.; Benford, D.; Blain, A.; Bridge, C.; Donoso, E.;

High resolution spectroscopy in the microwave and far infrared

Science.gov (United States)

Pickett, Herbert M.

1990-01-01

High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

High resolution and high speed positron emission tomography data acquisition

International Nuclear Information System (INIS)

Burgiss, S.G.; Byars, L.G.; Jones, W.F.; Casey, M.E.

1986-01-01

High resolution positron emission tomography (PET) requires many detectors. Thus, data collection systems for PET must have high data rates, wide data paths, and large memories to histogram the events. This design uses the VMEbus to cost effectively provide these features. It provides for several modes of operation including real time sorting, list mode data storage, and replay of stored list mode data

Ultra high spatial and temporal resolution breast imaging at 7T.

Science.gov (United States)

van de Bank, B L; Voogt, I J; Italiaander, M; Stehouwer, B L; Boer, V O; Luijten, P R; Klomp, D W J

2013-04-01

There is a need to obtain higher specificity in the detection of breast lesions using MRI. To address this need, Dynamic Contrast-Enhanced (DCE) MRI has been combined with other structural and functional MRI techniques. Unfortunately, owing to time constraints structural images at ultra-high spatial resolution can generally not be obtained during contrast uptake, whereas the relatively low spatial resolution of functional imaging (e.g. diffusion and perfusion) limits the detection of small lesions. To be able to increase spatial as well as temporal resolution simultaneously, the sensitivity of MR detection needs to increase as well as the ability to effectively accelerate the acquisition. The required gain in signal-to-noise ratio (SNR) can be obtained at 7T, whereas acceleration can be obtained with high-density receiver coil arrays. In this case, morphological imaging can be merged with DCE-MRI, and other functional techniques can be obtained at higher spatial resolution, and with less distortion [e.g. Diffusion Weighted Imaging (DWI)]. To test the feasibility of this concept, we developed a unilateral breast coil for 7T. It comprises a volume optimized dual-channel transmit coil combined with a 30-channel receive array coil. The high density of small coil elements enabled efficient acceleration in any direction to acquire ultra high spatial resolution MRI of close to 0.6 mm isotropic detail within a temporal resolution of 69 s, high spatial resolution MRI of 1.5 mm isotropic within an ultra high temporal resolution of 6.7 s and low distortion DWI at 7T, all validated in phantoms, healthy volunteers and a patient with a lesion in the right breast classified as Breast Imaging Reporting and Data System (BI-RADS) IV. Copyright © 2012 John Wiley & Sons, Ltd.

High-Resolution X-ray Emission and X-ray Absorption Spectroscopy

NARCIS (Netherlands)

Groot, F.M.F. de

2000-01-01

In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and reso-nant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption

High-resolution flurescence spectroscopy in immunoanalysis

Energy Technology Data Exchange (ETDEWEB)

Grubor, Nenad M. [Iowa State Univ., Ames, IA (United States)

2005-01-01

The work presented in this dissertation combines highly sensitive and selective fluorescence line-narrowing spectroscopy (FLNS) detection with various modes of immunoanalytical techniques. It has been shown that FLNS is capable of directly probing molecules immunocomplexed with antibodies, eliminating analytical ambiguities that may arise from interferences that accompany traditional immunochemical techniques. Moreover, the utilization of highly cross-reactive antibodies for highly specific analyte determination has been demonstrated. Finally, they demonstrate the first example of the spectral resolution of diastereomeric analytes based on their interaction with a cross-reactive antibody.

Analysis and Application of High Resolution Numerical Perturbation Algorithm for Convective-Diffusion Equation

International Nuclear Information System (INIS)

Gao Zhi; Shen Yi-Qing

2012-01-01

The high resolution numerical perturbation (NP) algorithm is analyzed and tested using various convective-diffusion equations. The NP algorithm is constructed by splitting the second order central difference schemes of both convective and diffusion terms of the convective-diffusion equation into upstream and downstream parts, then the perturbation reconstruction functions of the convective coefficient are determined using the power-series of grid interval and eliminating the truncated errors of the modified differential equation. The important nature, i.e. the upwind dominance nature, which is the basis to ensuring that the NP schemes are stable and essentially oscillation free, is firstly presented and verified. Various numerical cases show that the NP schemes are efficient, robust, and more accurate than the original second order central scheme

A computational atlas of the hippocampal formation using ex vivo, ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI.

Science.gov (United States)

Iglesias, Juan Eugenio; Augustinack, Jean C; Nguyen, Khoa; Player, Christopher M; Player, Allison; Wright, Michelle; Roy, Nicole; Frosch, Matthew P; McKee, Ann C; Wald, Lawrence L; Fischl, Bruce; Van Leemput, Koen

2015-07-15

Automated analysis of MRI data of the subregions of the hippocampus requires computational atlases built at a higher resolution than those that are typically used in current neuroimaging studies. Here we describe the construction of a statistical atlas of the hippocampal formation at the subregion level using ultra-high resolution, ex vivo MRI. Fifteen autopsy samples were scanned at 0.13 mm isotropic resolution (on average) using customized hardware. The images were manually segmented into 13 different hippocampal substructures using a protocol specifically designed for this study; precise delineations were made possible by the extraordinary resolution of the scans. In addition to the subregions, manual annotations for neighboring structures (e.g., amygdala, cortex) were obtained from a separate dataset of in vivo, T1-weighted MRI scans of the whole brain (1mm resolution). The manual labels from the in vivo and ex vivo data were combined into a single computational atlas of the hippocampal formation with a novel atlas building algorithm based on Bayesian inference. The resulting atlas can be used to automatically segment the hippocampal subregions in structural MRI images, using an algorithm that can analyze multimodal data and adapt to variations in MRI contrast due to differences in acquisition hardware or pulse sequences. The applicability of the atlas, which we are releasing as part of FreeSurfer (version 6.0), is demonstrated with experiments on three different publicly available datasets with different types of MRI contrast. The results show that the atlas and companion segmentation method: 1) can segment T1 and T2 images, as well as their combination, 2) replicate findings on mild cognitive impairment based on high-resolution T2 data, and 3) can discriminate between Alzheimer's disease subjects and elderly controls with 88% accuracy in standard resolution (1mm) T1 data, significantly outperforming the atlas in FreeSurfer version 5.3 (86% accuracy) and

Development of a high-resolution cavity-beam position monitor

Directory of Open Access Journals (Sweden)

Yoichi Inoue

2008-06-01

Full Text Available We have developed a high-resolution cavity-beam position monitor (BPM to be used at the focal point of the ATF2, which is a test beam line that is now being built to demonstrate stable orbit control at ∼nanometer resolution. The design of the cavity structure was optimized for the Accelerator Test Facility (ATF beam in various ways. For example, the cavity has a rectangular shape in order to isolate two dipole modes in orthogonal directions, and a relatively thin gap that is less sensitive to trajectory inclination. A two stage homodyne mixer with highly sensitive electronics and phase-sensitive detection was also developed. Two BPM blocks, each containing two cavity BPMs, were installed in the existing ATF beam line using a rigid support frame. After testing the basic characteristics, we measured the resolution using three BPMs. The system demonstrated 8.7 nm position resolution over a dynamic range of 5  μm.

Development of a high-resolution cavity-beam position monitor

Science.gov (United States)

Inoue, Yoichi; Hayano, Hitoshi; Honda, Yosuke; Takatomi, Toshikazu; Tauchi, Toshiaki; Urakawa, Junji; Komamiya, Sachio; Nakamura, Tomoya; Sanuki, Tomoyuki; Kim, Eun-San; Shin, Seung-Hwan; Vogel, Vladimir

2008-06-01

We have developed a high-resolution cavity-beam position monitor (BPM) to be used at the focal point of the ATF2, which is a test beam line that is now being built to demonstrate stable orbit control at ˜nanometer resolution. The design of the cavity structure was optimized for the Accelerator Test Facility (ATF) beam in various ways. For example, the cavity has a rectangular shape in order to isolate two dipole modes in orthogonal directions, and a relatively thin gap that is less sensitive to trajectory inclination. A two stage homodyne mixer with highly sensitive electronics and phase-sensitive detection was also developed. Two BPM blocks, each containing two cavity BPMs, were installed in the existing ATF beam line using a rigid support frame. After testing the basic characteristics, we measured the resolution using three BPMs. The system demonstrated 8.7 nm position resolution over a dynamic range of 5μm.

Optimized computational imaging methods for small-target sensing in lens-free holographic microscopy

Science.gov (United States)

Xiong, Zhen; Engle, Isaiah; Garan, Jacob; Melzer, Jeffrey E.; McLeod, Euan

2018-02-01

Lens-free holographic microscopy is a promising diagnostic approach because it is cost-effective, compact, and suitable for point-of-care applications, while providing high resolution together with an ultra-large field-of-view. It has been applied to biomedical sensing, where larger targets like eukaryotic cells, bacteria, or viruses can be directly imaged without labels, and smaller targets like proteins or DNA strands can be detected via scattering labels like micro- or nano-spheres. Automated image processing routines can count objects and infer target concentrations. In these sensing applications, sensitivity and specificity are critically affected by image resolution and signal-to-noise ratio (SNR). Pixel super-resolution approaches have been shown to boost resolution and SNR by synthesizing a high-resolution image from multiple, partially redundant, low-resolution images. However, there are several computational methods that can be used to synthesize the high-resolution image, and previously, it has been unclear which methods work best for the particular case of small-particle sensing. Here, we quantify the SNR achieved in small-particle sensing using regularized gradient-descent optimization method, where the regularization is based on cardinal-neighbor differences, Bayer-pattern noise reduction, or sparsity in the image. In particular, we find that gradient-descent with sparsity-based regularization works best for small-particle sensing. These computational approaches were evaluated on images acquired using a lens-free microscope that we assembled from an off-the-shelf LED array and color image sensor. Compared to other lens-free imaging systems, our hardware integration, calibration, and sample preparation are particularly simple. We believe our results will help to enable the best performance in lens-free holographic sensing.

Classification of high resolution satellite images

OpenAIRE

Karlsson, Anders

2003-01-01

In this thesis the Support Vector Machine (SVM)is applied on classification of high resolution satellite images. Sveral different measures for classification, including texture mesasures, 1st order statistics, and simple contextual information were evaluated. Additionnally, the image was segmented, using an enhanced watershed method, in order to improve the classification accuracy.

High-resolution and high-throughput multichannel Fourier transform spectrometer with two-dimensional interferogram warping compensation

Science.gov (United States)

Watanabe, A.; Furukawa, H.

2018-04-01

The resolution of multichannel Fourier transform (McFT) spectroscopy is insufficient for many applications despite its extreme advantage of high throughput. We propose an improved configuration to realise both performance using a two-dimensional area sensor. For the spectral resolution, we obtained the interferogram of a larger optical path difference by shifting the area sensor without altering any optical components. The non-linear phase error of the interferometer was successfully corrected using a phase-compensation calculation. Warping compensation was also applied to realise a higher throughput to accumulate the signal between vertical pixels. Our approach significantly improved the resolution and signal-to-noise ratio by factors of 1.7 and 34, respectively. This high-resolution and high-sensitivity McFT spectrometer will be useful for detecting weak light signals such as those in non-invasive diagnosis.

A new method for high-resolution characterization of hydraulic conductivity

Science.gov (United States)

Liu, Gaisheng; Butler, J.J.; Bohling, Geoffrey C.; Reboulet, Ed; Knobbe, Steve; Hyndman, D.W.

2009-01-01

A new probe has been developed for high-resolution characterization of hydraulic conductivity (K) in shallow unconsolidated formations. The probe was recently applied at the Macrodispersion Experiment (MADE) site in Mississippi where K was rapidly characterized at a resolution as fine as 0.015 m, which has not previously been possible. Eleven profiles were obtained with K varying up to 7 orders of magnitude in individual profiles. Currently, high-resolution (0.015-m) profiling has an upper K limit of 10 m/d; lower-resolution (???0.4-m) mode is used in more permeable zones pending modifications. The probe presents a new means to help address unresolved issues of solute transport in heterogeneous systems. Copyright 2009 by the American Geophysical Union.

Evaluation of a High-Resolution Regional Reanalysis for Europe

Science.gov (United States)

Ohlwein, C.; Wahl, S.; Keller, J. D.; Bollmeyer, C.

2014-12-01

Reanalyses gain more and more importance as a source of meteorological information for many purposes and applications. Several global reanalyses projects (e.g., ERA, MERRA, CSFR, JMA9) produce and verify these data sets to provide time series as long as possible combined with a high data quality. Due to a spatial resolution down to 50-70km and 3-hourly temporal output, they are not suitable for small scale problems (e.g., regional climate assessment, meso-scale NWP verification, input for subsequent models such as river runoff simulations). The implementation of regional reanalyses based on a limited area model along with a data assimilation scheme is able to generate reanalysis data sets with high spatio-temporal resolution. Within the Hans-Ertel-Centre for Weather Research (HErZ), the climate monitoring branch concentrates efforts on the assessment and analysis of regional climate in Germany and Europe. In joint cooperation with DWD (German Meteorological Service), a high-resolution reanalysis system based on the COSMO model has been developed. The regional reanalysis for Europe matches the domain of the CORDEX EURO-11 specifications, albeit at a higher spatial resolution, i.e., 0.055° (6km) instead of 0.11° (12km) and comprises the assimilation of observational data using the existing nudging scheme of COSMO complemented by a special soil moisture analysis with boundary conditions provided by ERA-Interim data. The reanalysis data set covers 6 years (2007-2012) and is currently extended to 16 years. Extensive evaluation of the reanalysis is performed using independent observations with special emphasis on precipitation and high-impact weather situations indicating a better representation of small scale variability. Further, the evaluation shows an added value of the regional reanalysis with respect to the forcing ERA Interim reanalysis and compared to a pure high-resolution dynamical downscaling approach without data assimilation.

High resolution satellite imagery : from spies to pipeline management

Energy Technology Data Exchange (ETDEWEB)

Adam, S. [Canadian Geomatic Solutions Ltd., Calgary, AB (Canada); Farrell, M. [TransCanada Transmission, Calgary, AB (Canada)

2000-07-01

The launch of Space Imaging's IKONOS satellite in September 1999 has opened the door for corridor applications. The technology has been successfully implemented by TransCanada PipeLines in mapping over 1500 km of their mainline. IKONOS is the world's first commercial high resolution satellite which collects data at 1-meter black/white and 4-meter multi-spectral. Its use is regulated by the U.S. government. It is the best source of high resolution satellite image data. Other sources include the Indian Space Agency's IRS-1 C/D satellite and the Russian SPIN-2 which provides less reliable coverage. In addition, two more high resolution satellites may be launched this year to provide imagery every day of the year. IKONOS scenes as narrow as 5 km can be purchased. TransCanada conducted a pilot study to determine if high resolution satellite imagery is as effective as ortho-photos for identifying population structures within a buffer of TransCanada's east line right-of-way. The study examined three unique segments where residential, commercial, industrial and public features were compared. It was determined that IKONOS imagery is as good as digital ortho-photos for updating structures from low to very high density areas. The satellite imagery was also logistically easier than ortho-photos to acquire. This will be even more evident when the IKONOS image archives begins to grow. 4 tabs., 3 figs.

High resolution radar satellite imagery analysis for safeguards applications

Energy Technology Data Exchange (ETDEWEB)

Minet, Christian; Eineder, Michael [German Aerospace Center, Remote Sensing Technology Institute, Department of SAR Signal Processing, Wessling, (Germany); Rezniczek, Arnold [UBA GmbH, Herzogenrath, (Germany); Niemeyer, Irmgard [Forschungszentrum Juelich, Institue of Energy and Climate Research, IEK-6: Nuclear Waste Management and Reactor Safety, Juelich, (Germany)

2011-12-15

For monitoring nuclear sites, the use of Synthetic Aperture Radar (SAR) imagery shows essential promises. Unlike optical remote sensing instruments, radar sensors operate under almost all weather conditions and independently of the sunlight, i.e. time of the day. Such technical specifications are required both for continuous and for ad-hoc, timed surveillance tasks. With Cosmo-Skymed, TerraSARX and Radarsat-2, high-resolution SAR imagery with a spatial resolution up to 1m has recently become available. Our work therefore aims to investigate the potential of high-resolution TerraSAR data for nuclear monitoring. This paper focuses on exploiting amplitude of a single acquisition, assessing amplitude changes and phase differences between two acquisitions, and PS-InSAR processing of an image stack.

Effects of display resolution and size on primary diagnosis of chest images using a high-resolution electronic work station

International Nuclear Information System (INIS)

Fuhrman, C.R.; Cooperstein, L.A.; Herron, J.; Good, W.F.; Good, B.; Gur, D.; Maitz, G.; Tabor, E.; Hoy, R.J.

1987-01-01

To evaluate the acceptability of electronically displayed planar images, the authors have a high-resolution work station. This system utilizes a high-resolution film digitizer (100-micro resolution) interfaced to a mainframe computer and two high-resolution (2,048 X 2,048) display devices (Azuray). In a clinically simulated multiobserver blind study (19 cases and five observers) a prodetermined series of reading sessions is stored on magnetic disk and is transferred to the displays while the preceding set of images is being reviewed. Images can be linearly processed on the fly into 2,000 X 2,000 full resolution, 1,000 X 1,000 minified display, or 1,000 X 1,000 interpolated for full-size display. Results of the study indicate that radiologists accept but do not like significant minification (more than X2), and they rate 2,000 X 2,000 images as having better diagnostic quality than 1,000 X 1,000 images

High-resolution phylogenetic microbial community profiling

Energy Technology Data Exchange (ETDEWEB)

Singer, Esther; Coleman-Derr, Devin; Bowman, Brett; Schwientek, Patrick; Clum, Alicia; Copeland, Alex; Ciobanu, Doina; Cheng, Jan-Fang; Gies, Esther; Hallam, Steve; Tringe, Susannah; Woyke, Tanja

2014-03-17

The representation of bacterial and archaeal genome sequences is strongly biased towards cultivated organisms, which belong to merely four phylogenetic groups. Functional information and inter-phylum level relationships are still largely underexplored for candidate phyla, which are often referred to as microbial dark matter. Furthermore, a large portion of the 16S rRNA gene records in the GenBank database are labeled as environmental samples and unclassified, which is in part due to low read accuracy, potential chimeric sequences produced during PCR amplifications and the low resolution of short amplicons. In order to improve the phylogenetic classification of novel species and advance our knowledge of the ecosystem function of uncultivated microorganisms, high-throughput full length 16S rRNA gene sequencing methodologies with reduced biases are needed. We evaluated the performance of PacBio single-molecule real-time (SMRT) sequencing in high-resolution phylogenetic microbial community profiling. For this purpose, we compared PacBio and Illumina metagenomic shotgun and 16S rRNA gene sequencing of a mock community as well as of an environmental sample from Sakinaw Lake, British Columbia. Sakinaw Lake is known to contain a large age of microbial species from candidate phyla. Sequencing results show that community structure based on PacBio shotgun and 16S rRNA gene sequences is highly similar in both the mock and the environmental communities. Resolution power and community representation accuracy from SMRT sequencing data appeared to be independent of GC content of microbial genomes and was higher when compared to Illumina-based metagenome shotgun and 16S rRNA gene (iTag) sequences, e.g. full-length sequencing resolved all 23 OTUs in the mock community, while iTags did not resolve closely related species. SMRT sequencing hence offers various potential benefits when characterizing uncharted microbial communities.

Spitzer Trigonometric Parallaxes of L, T, and Y Dwarfs: Complementing Gaia's Optically-selected Census of Nearby Stars

Science.gov (United States)

Kirkpatrick, J. Davy; Smart, Richard; Marocco, Federico; Martin, Emily; Faherty, Jacqueline; Tinney, Christopher; Cushing, Michael; Beichman, Charles; Gelino, Christopher; Schneider, Adam; Wright, Edward; Lowrance, Patrick; Ingalls, James

2018-05-01

We now find ourselves at a moment in history where a parallax-selected census of nearby objects from the hottest A stars to the coldest Y dwarfs is almost a reality. With the release of Gaia DR2 in April of this year, we will be able to extract a volume-limited sample of stars out to 20 pc down to a spectral type of L5. Extending the census to colder types is much more difficult but nonetheless possible and essential. Ground-based astrometric monitoring of some of these colder dwarfs can be done with deep infrared detections on moderate to large (4+ meter) telescopes, but given the amount of time needed, only a portion of the colder objects believed to lie within 20 pc has been monitored. Our prior Spitzer observations have already enabled direct distance measures for T6 through Y dwarfs, but many 20-pc objects with spectral types between L5 and T5.5 have still not been astrometrically monitored, leaving a hole in our knowledge of this important all-sky sample. Spitzer Cycle 14 observations of modest time expenditure can rectify this problem by providing parallaxes for the 150+ objects remaining. Analysis of the brown dwarfs targeted by Spitzer is particularly important because it will provide insight into the low-mass cutoff of star formation, the shape of the mass function as inferred from the observed temperature distribution, the binary fraction of near-equal mass doubles, and the prevalence of extremely young (low-gravity) and extremely old (low metallicity) objects within the sample - all of which can be used to test and further refine model predictions of the underlying mass function.

Analysis strategies for high-resolution UHF-fMRI data.

Science.gov (United States)

Polimeni, Jonathan R; Renvall, Ville; Zaretskaya, Natalia; Fischl, Bruce

2018-03-01

Functional MRI (fMRI) benefits from both increased sensitivity and specificity with increasing magnetic field strength, making it a key application for Ultra-High Field (UHF) MRI scanners. Most UHF-fMRI studies utilize the dramatic increases in sensitivity and specificity to acquire high-resolution data reaching sub-millimeter scales, which enable new classes of experiments to probe the functional organization of the human brain. This review article surveys advanced data analysis strategies developed for high-resolution fMRI at UHF. These include strategies designed to mitigate distortion and artifacts associated with higher fields in ways that attempt to preserve spatial resolution of the fMRI data, as well as recently introduced analysis techniques that are enabled by these extremely high-resolution data. Particular focus is placed on anatomically-informed analyses, including cortical surface-based analysis, which are powerful techniques that can guide each step of the analysis from preprocessing to statistical analysis to interpretation and visualization. New intracortical analysis techniques for laminar and columnar fMRI are also reviewed and discussed. Prospects for single-subject individualized analyses are also presented and discussed. Altogether, there are both specific challenges and opportunities presented by UHF-fMRI, and the use of proper analysis strategies can help these valuable data reach their full potential. Copyright © 2017 Elsevier Inc. All rights reserved.

High-field/ high-frequency EPR study on stable free radicals formed in sucrose by gamma-irradiation.

Science.gov (United States)

Georgieva, Elka R; Pardi, Luca; Jeschke, Gunnar; Gatteschi, Dante; Sorace, Lorenzo; Yordanov, Nicola D

2006-06-01

The EPR spectrum of sucrose irradiated by high-energy radiation is complex due to the presence of more than one radical species. In order to decompose the spectrum and elucidate the radical magnetic parameters a high-field (HF(-)EPR) study on stable free radicals in gamma-irradiated polycrystalline sucrose (table sugar) was performed at three different high frequencies--94, 190 and 285 GHz as well as at the conventional X-band. We suggest a presence of three stable radicals R1, R2 and R3 as the main radical species. Due to the increase of g-factor resolution at high fields the g-tensors of these radicals could be extracted by accurate simulations. The moderate g-anisotropy suggests that all three radicals are carbon-centred. Results from an earlier ENDOR study on X-irradiated sucrose single crystals (Vanhaelewyn et al., Appl Radiat Isot, 52, 1221 (2000)) were used for analyzing of the spectra in more details. It was confirmed that the strongest hyperfine interaction has a relatively small anisotropy, which indicates either the absence of alpha-protons or a strongly distorted geometry of the radicals.

Measuring the hydrogen/deuterium exchange of proteins at high spatial resolution by mass spectrometry

DEFF Research Database (Denmark)

Rand, Kasper Dyrberg; Zehl, Martin; Jørgensen, Thomas J D

2014-01-01

, and eventually all of the protecting hydrogen bonds will transiently break as the protein-according to thermodynamic principles-cycles through partially unfolded states that correspond to excited free energy levels. As a result, all of the backbone amides will eventually become temporarily solvent....../dysfunction and conformational dynamics requires in many cases higher resolution and ultimately single-residue resolution. In this Account, we summarize our efforts to achieve single-residue deuterium levels in proteins by electron-based or laser-induced gas-phase fragmentation methods. A crucial analytical requirement...

A simple and high-resolution stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks

International Nuclear Information System (INIS)

Wang, Zongjie; Parker, Benjamin; Samanipour, Roya; Kim, Keekyoung; Abdulla, Raafa; Ghosh, Sanjoy

2015-01-01

Bioprinting is a rapidly developing technique for biofabrication. Because of its high resolution and the ability to print living cells, bioprinting has been widely used in artificial tissue and organ generation as well as microscale living cell deposition. In this paper, we present a low-cost stereolithography-based bioprinting system that uses visible light crosslinkable bioinks. This low-cost stereolithography system was built around a commercial projector with a simple water filter to prevent harmful infrared radiation from the projector. The visible light crosslinking was achieved by using a mixture of polyethylene glycol diacrylate (PEGDA) and gelatin methacrylate (GelMA) hydrogel with eosin Y based photoinitiator. Three different concentrations of hydrogel mixtures (10% PEG, 5% PEG + 5% GelMA, and 2.5% PEG + 7.5% GelMA, all w/v) were studied with the presented systems. The mechanical properties and microstructure of the developed bioink were measured and discussed in detail. Several cell-free hydrogel patterns were generated to demonstrate the resolution of the solution. Experimental results with NIH 3T3 fibroblast cells show that this system can produce a highly vertical 3D structure with 50 μm resolution and 85% cell viability for at least five days. The developed system provides a low-cost visible light stereolithography solution and has the potential to be widely used in tissue engineering and bioengineering for microscale cell patterning. (paper)

A simple and high-resolution stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks.

Science.gov (United States)

Wang, Zongjie; Abdulla, Raafa; Parker, Benjamin; Samanipour, Roya; Ghosh, Sanjoy; Kim, Keekyoung

2015-12-22

Bioprinting is a rapidly developing technique for biofabrication. Because of its high resolution and the ability to print living cells, bioprinting has been widely used in artificial tissue and organ generation as well as microscale living cell deposition. In this paper, we present a low-cost stereolithography-based bioprinting system that uses visible light crosslinkable bioinks. This low-cost stereolithography system was built around a commercial projector with a simple water filter to prevent harmful infrared radiation from the projector. The visible light crosslinking was achieved by using a mixture of polyethylene glycol diacrylate (PEGDA) and gelatin methacrylate (GelMA) hydrogel with eosin Y based photoinitiator. Three different concentrations of hydrogel mixtures (10% PEG, 5% PEG + 5% GelMA, and 2.5% PEG + 7.5% GelMA, all w/v) were studied with the presented systems. The mechanical properties and microstructure of the developed bioink were measured and discussed in detail. Several cell-free hydrogel patterns were generated to demonstrate the resolution of the solution. Experimental results with NIH 3T3 fibroblast cells show that this system can produce a highly vertical 3D structure with 50 μm resolution and 85% cell viability for at least five days. The developed system provides a low-cost visible light stereolithography solution and has the potential to be widely used in tissue engineering and bioengineering for microscale cell patterning.

Contextually guided very-high-resolution imagery classification with semantic segments

Science.gov (United States)

Zhao, Wenzhi; Du, Shihong; Wang, Qiao; Emery, William J.

2017-10-01

Contextual information, revealing relationships and dependencies between image objects, is one of the most important information for the successful interpretation of very-high-resolution (VHR) remote sensing imagery. Over the last decade, geographic object-based image analysis (GEOBIA) technique has been widely used to first divide images into homogeneous parts, and then to assign semantic labels according to the properties of image segments. However, due to the complexity and heterogeneity of VHR images, segments without semantic labels (i.e., semantic-free segments) generated with low-level features often fail to represent geographic entities (such as building roofs usually be partitioned into chimney/antenna/shadow parts). As a result, it is hard to capture contextual information across geographic entities when using semantic-free segments. In contrast to low-level features, "deep" features can be used to build robust segments with accurate labels (i.e., semantic segments) in order to represent geographic entities at higher levels. Based on these semantic segments, semantic graphs can be constructed to capture contextual information in VHR images. In this paper, semantic segments were first explored with convolutional neural networks (CNN) and a conditional random field (CRF) model was then applied to model the contextual information between semantic segments. Experimental results on two challenging VHR datasets (i.e., the Vaihingen and Beijing scenes) indicate that the proposed method is an improvement over existing image classification techniques in classification performance (overall accuracy ranges from 82% to 96%).

Geographic Resolution Issues in RAM Transport Risk Analysis

International Nuclear Information System (INIS)

Mills, G.S.; Neuhauser, K.S.

2000-01-01

Transport risk analyses based on the RADTRAN code have been met with continual demands for increased spatial resolution of variations in population densities and other parameters employed in the calculation of risk estimates for transport of radioactive material (RAM). With the advent of geographic information systems (GISs) large quantities of data required to describe transport routes, which may extend to hundreds of kilometers, with high resolution (e.g. 1 km segments) can be handled without inordinate expense. This capability has raised a question concerning the maximum resolution of available input data and compatibility with RADTRAN computational models. Quantitative examinations are presented of spatial resolution issues in the calculation of incident-free doses and accident dose risks. For incident-free calculations, the effect of decreasing route-segment length on accuracy, in view of the model employed, is examined, and means of reducing total data input to the RADTRAN calculations, without loss of meaningful resolution of population concentrations, are presented. In the case of accident-risk calculations, the ability to detail population density under very large dispersal plumes permits comparison of plume modelling to actual data. In both types of calculations, meaningful limits to geographic extent are suggested. (author)

Ring artifact correction for high-resolution micro CT

International Nuclear Information System (INIS)

Kyriakou, Yiannis; Prell, Daniel; Kalender, Willi A

2009-01-01

In high-resolution micro CT using flat detectors (FD), imperfect or defect detector elements may cause concentric-ring artifacts due to their continuous over- or underestimation of attenuation values, which often disturb image quality. We here present a dedicated image-based ring artifact correction method for high-resolution micro CT, based on median filtering of the reconstructed image and working on a transformed version of the reconstructed images in polar coordinates. This post-processing method reduced ring artifacts in the reconstructed images and improved image quality for phantom and in in vivo scans. Noise and artifacts were reduced both in transversal and in multi-planar reformations along the longitudinal axis. (note)

Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C61-butyric acid methyl ester

OpenAIRE

Lazzerini, GM; Paterno, GM; Tregnago, G; Treat, N; Stingelin, N; Yacoot, A; Cacialli, F

2016-01-01

We report high-resolution, traceable atomic force microscopymeasurements of high-quality, solvent-free single crystals of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). These were grown by drop-casting PCBM solutions onto the spectrosil substrates and by removing the residual solvent in a vacuum. A home-built atomic force microscope featuring a plane mirror differential optical interferometer, fiber-fed from a frequency-stabilized laser (emitting at 632.8???nm), was used to measure the cr...

Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C-61-butyric acid methyl ester

OpenAIRE

Lazzerini, G. M.; Paterno, G. M.; Tregnago, G.; Treat, N.; Stingelin, N.; Yacoot, A.; Cacialli, F.

2016-01-01

We report high-resolution, traceable atomic force microscopymeasurements of high-quality, solvent-free single crystals of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). These were grown by drop-casting PCBM solutions onto the spectrosil substrates and by removing the residual solvent in a vacuum. A home-built atomic force microscope featuring a plane mirror differential optical interferometer, fiber-fed from a frequency-stabilized laser (emitting at 632.8 nm), was used to measure the crys...

Digital approach to high-resolution pulse processing for semiconductor detectors

International Nuclear Information System (INIS)

Georgiev, A.; Buchner, A.; Gast, W.; Lieder, R.M.

1992-01-01

A new design philosophy for processing signals produced by high resolution, large volume semiconductor detectors is described. These detectors, to be used in the next generation of spectrometer arrays for nuclear research (i.e. EUROBALL, etc.), present a set of problems like resolution degradation due to charge trapping and ballistic defect effects, low resolution at a high count rate, poor long term stability, etc. To solve these problems, a new design approach has been developed, including reconstruction of the event charge, providing a pure triangular residual function, and suppressing low frequency noise. 5 refs., 4 figs

Digital approach to high-resolution pulse processing for semiconductor detectors

Energy Technology Data Exchange (ETDEWEB)

Georgiev, A [Sofia Univ. (Bulgaria); Buchner, A [Forschungszentrum Rossendorf (Germany); Gast, W; Lieder, R M [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Stein, J [Target System Electronic GmbH, Solingen, (Germany)

1992-08-01

A new design philosophy for processing signals produced by high resolution, large volume semiconductor detectors is described. These detectors, to be used in the next generation of spectrometer arrays for nuclear research (i.e. EUROBALL, etc.), present a set of problems like resolution degradation due to charge trapping and ballistic defect effects, low resolution at a high count rate, poor long term stability, etc. To solve these problems, a new design approach has been developed, including reconstruction of the event charge, providing a pure triangular residual function, and suppressing low frequency noise. 5 refs., 4 figs.

Evidence for radiation induced crosslinking in polytetrafluoroethylene by means of high-resolution solid-state 19F high-speed MAS NMR

International Nuclear Information System (INIS)

Katoh, Etsuko; Sugisawa, Hisashi; Oshima, Akihiro; Tabata, Yoneho; Seguchi, Tadao; Yamazaki, Toshimasa

1999-01-01

Radiation effects on molecular structure of polytetrafluoroethylene (PTFE) were studied by high-resolution solid-state 19 F high speed magic angle spinning (HS MAS) NMR spectroscopy. Samples used for the NMR studies were prepared by electron beam irradiation of PTFE with a wide range of irradiation doses from 0.5-10 MGy in the molten state at 340 deg. C under oxygen-free atmosphere. While the non-irradiated PTFE displayed only an intense peak of the internal CF 2 , several new signals corresponding to CF 3 , CF 2 and CF groups were observed for the PTFE which was high temperature irradiated at 340 deg. C in oxygen-free atmosphere (hti-PTFE). Intensities of these new signals increased with an increase of irradiation dose. The present solid-state 19 F HS MAS NMR studies provide not only the first experimental evidence regarding the existence of crosslinking structure in hti-PTFE, directly detected as the CF signal, but also the crosslinking density which can be estimated from a proportion of the CF versus total fluorine signal intensities. The higher the irradiation dose, the higher the crosslinking density; hti-PTFE with 10 MGy contains one crosslinking site per approximately 24 CF 2 groups, while the hti-PTFE with 5 MGy contains one crosslinking site per approximately 36 CF 2 groups. Further, G value of crosslinking (G(x)) was estimated from the signal intensities of 19 F HS MAS NMR spectra. The highest G(x)-value, 1.85, was observed for the 2MGy hti-PTFE sample, suggesting that crosslinking of PTFE is formed most efficaciously with 2 MGy irradiation in the molten state at 340 deg. C under oxygen-free atmosphere

High Resolution Insights into Snow Distribution Provided by Drone Photogrammetry

Science.gov (United States)

Redpath, T.; Sirguey, P. J.; Cullen, N. J.; Fitzsimons, S.

2017-12-01

Dynamic in time and space, New Zealand's seasonal snow is largely confined to remote alpine areas, complicating ongoing in situ measurement and characterisation. Improved understanding and modeling of the seasonal snowpack requires fine scale resolution of snow distribution and spatial variability. The potential of remotely piloted aircraft system (RPAS) photogrammetry to resolve spatial and temporal variability of snow depth and water equivalent in a New Zealand alpine catchment is assessed in the Pisa Range, Central Otago. This approach yielded orthophotomosaics and digital surface models (DSM) at 0.05 and 0.15 m spatial resolution, respectively. An autumn reference DSM allowed mapping of winter (02/08/2016) and spring (10/09/2016) snow depth at 0.15 m spatial resolution, via DSM differencing. The consistency and accuracy of the RPAS-derived surface was assessed by comparison of snow-free regions of the spring and autumn DSMs, while accuracy of RPAS retrieved snow depth was assessed with 86 in situ snow probe measurements. Results show a mean vertical residual of 0.024 m between DSMs acquired in autumn and spring. This residual approximated a Laplace distribution, reflecting the influence of large outliers on the small overall bias. Propagation of errors associated with successive DSMs saw snow depth mapped with an accuracy of ± 0.09 m (95% c.l.). Comparing RPAS and in situ snow depth measurements revealed the influence of geo-location uncertainty and interactions between vegetation and the snowpack on snow depth uncertainty and bias. Semi-variogram analysis revealed that the RPAS outperformed systematic in situ measurements in resolving fine scale spatial variability. Despite limitations accompanying RPAS photogrammetry, this study demonstrates a repeatable means of accurately mapping snow depth for an entire, yet relatively small, hydrological basin ( 0.5 km2), at high resolution. Resolving snowpack features associated with re-distribution and preferential

Enhancing GIS Capabilities for High Resolution Earth Science Grids

Science.gov (United States)

Koziol, B. W.; Oehmke, R.; Li, P.; O'Kuinghttons, R.; Theurich, G.; DeLuca, C.

2017-12-01

Applications for high performance GIS will continue to increase as Earth system models pursue more realistic representations of Earth system processes. Finer spatial resolution model input and output, unstructured or irregular modeling grids, data assimilation, and regional coordinate systems present novel challenges for GIS frameworks operating in the Earth system modeling domain. This presentation provides an overview of two GIS-driven applications that combine high performance software with big geospatial datasets to produce value-added tools for the modeling and geoscientific community. First, a large-scale interpolation experiment using National Hydrography Dataset (NHD) catchments, a high resolution rectilinear CONUS grid, and the Earth System Modeling Framework's (ESMF) conservative interpolation capability will be described. ESMF is a parallel, high-performance software toolkit that provides capabilities (e.g. interpolation) for building and coupling Earth science applications. ESMF is developed primarily by the NOAA Environmental Software Infrastructure and Interoperability (NESII) group. The purpose of this experiment was to test and demonstrate the utility of high performance scientific software in traditional GIS domains. Special attention will be paid to the nuanced requirements for dealing with high resolution, unstructured grids in scientific data formats. Second, a chunked interpolation application using ESMF and OpenClimateGIS (OCGIS) will demonstrate how spatial subsetting can virtually remove computing resource ceilings for very high spatial resolution interpolation operations. OCGIS is a NESII-developed Python software package designed for the geospatial manipulation of high-dimensional scientific datasets. An overview of the data processing workflow, why a chunked approach is required, and how the application could be adapted to meet operational requirements will be discussed here. In addition, we'll provide a general overview of OCGIS

A Non-hydrostatic Atmospheric Model for Global High-resolution Simulation

Science.gov (United States)

Peng, X.; Li, X.

2017-12-01

A three-dimensional non-hydrostatic atmosphere model, GRAPES_YY, is developed on the spherical Yin-Yang grid system in order to enforce global high-resolution weather simulation or forecasting at the CAMS/CMA. The quasi-uniform grid makes the computation be of high efficiency and free of pole problem. Full representation of the three-dimensional Coriolis force is considered in the governing equations. Under the constraint of third-order boundary interpolation, the model is integrated with the semi-implicit semi-Lagrangian method using the same code on both zones. A static halo region is set to ensure computation of cross-boundary transport and updating Dirichlet-type boundary conditions in the solution process of elliptical equations with the Schwarz method. A series of dynamical test cases, including the solid-body advection, the balanced geostrophic flow, zonal flow over an isolated mountain, development of the Rossby-Haurwitz wave and a baroclinic wave, are carried out, and excellent computational stability and accuracy of the dynamic core has been confirmed. After implementation of the physical processes of long and short-wave radiation, cumulus convection, micro-physical transformation of water substances and the turbulent processes in the planetary boundary layer include surface layer vertical fluxes parameterization, a long-term run of the model is then put forward under an idealized aqua-planet configuration to test the model physics and model ability in both short-term and long-term integrations. In the aqua-planet experiment, the model shows an Earth-like structure of circulation. The time-zonal mean temperature, wind components and humidity illustrate reasonable subtropical zonal westerly jet, meridional three-cell circulation, tropical convection and thermodynamic structures. The specific SST and solar insolation being symmetric about the equator enhance the ITCZ and tropical precipitation, which concentrated in tropical region. Additional analysis and

Computer simulation of high resolution transmission electron micrographs: theory and analysis

International Nuclear Information System (INIS)

Kilaas, R.

1985-03-01

Computer simulation of electron micrographs is an invaluable aid in their proper interpretation and in defining optimum conditions for obtaining images experimentally. Since modern instruments are capable of atomic resolution, simulation techniques employing high precision are required. This thesis makes contributions to four specific areas of this field. First, the validity of a new method for simulating high resolution electron microscope images has been critically examined. Second, three different methods for computing scattering amplitudes in High Resolution Transmission Electron Microscopy (HRTEM) have been investigated as to their ability to include upper Laue layer (ULL) interaction. Third, a new method for computing scattering amplitudes in high resolution transmission electron microscopy has been examined. Fourth, the effect of a surface layer of amorphous silicon dioxide on images of crystalline silicon has been investigated for a range of crystal thicknesses varying from zero to 2 1/2 times that of the surface layer

Close-range airborne Structure-from-Motion Photogrammetry for high-resolution beach morphometric surveys: Examples from an embayed rotating beach

Science.gov (United States)

Brunier, Guillaume; Fleury, Jules; Anthony, Edward J.; Gardel, Antoine; Dussouillez, Philippe

2016-05-01

points, we obtained a mean vertical accuracy less than ± 10 cm, with a maximum of 20 cm in marginal sectors with sparse vegetation and in the lower intertidal zone where water-saturated surfaces generated lower-resolution data as a result of a lack of coherence between photographs. The overall results show that SfM photogrammetry is a robust tool for beach morphological and sediment budget surveys. Our SfM workflow enabled the discrimination of beach surface features at a scale of a few tens of centimetres despite the low textural contrasts exhibited by the quartz beach sand and the relatively uniform upper beach topography, as well as the calculation of beach sediment budgets. 66,000 m³ of sand were removed from the northern sector of the beach, of which 22,000 m³ were transferred to the southern sector in the course of rotation. Finally, we briefly highlight: (1) the advantages of SfM photogrammetry compared to other high-resolution survey methods, (2) the advantages and disadvantages of, respectively, a microlight aircraft and an unmanned aerial vehicle (UAV) in undertaking SfM photogrammetry, and (3) areas of potential future improvement of the SfM workflow technique. These concern more extensive cross-shore deployment of ground control points to reduce possible tilt, and oblique cross-shore photography to improve parallax.

Alignment and Distortion-Free Integration of Lightweight Mirrors into Meta-Shells for High-Resolution Astronomical X-Ray Optics

Science.gov (United States)

Chan, Kai-Wing; Zhang, William W.; Schofield, Mark J.; Numata, Ai; Mazzarella, James R.; Saha, Timo T.; Biskach, Michael P.; McCelland, Ryan S.; Niemeyer, Jason; Sharpe, Marton V.;

Application of MCM image construction to IRAS comet observations

Science.gov (United States)

Schlapfer, Martin F.; Walker, Russell G.

1994-01-01

There is a wealth of IRAS comet data, obtained in both the survey and pointed observations modes. However, these measurements have remained largely untouched due to difficulties in removing instrumental effects from the data. We have developed a version of the Maximum Correlation Method for Image Construction algorithm (MCM) which operates in the moving coordinate system of the comet and properly treats both real cometary motion and apparent motion due to spacecraft parallax. This algorithm has been implemented on a 486/33 PC in FORTRAN and IDL codes. Preprocessing of the IRAS CRDD includes baseline removal, deglitching, and removal of long tails due to dielectric time constants of the detectors. The resulting images are virtually free from instrumental effects and have the highest possible spatial resolution consistent with the data sampling. We present examples of high resolution IRAS images constructed from survey observations of Comets P/Tempel 1 and P/Tempel 2, and pointed observations of IRAS-Araki-Alcock.

Bio-inspired nano-photodiode for Low Light, High Resolution and crosstalk-free CMOS image sensing

KAUST Repository

Saffih, Faycal

2011-05-01

Previous attempts have been devoted to mimic biological vision intelligence at the architectural system level. In this paper, a novel imitation of biological visual system intelligence is suggested, at the device level with the introduction of novel photodiode morphology. The proposed bio-inspired nanorod photodiode puts the depletion region length on the path of the incident photon instead of on its width, as the case is with the planar photodiodes. The depletion region has a revolving volume to increase the photodiode responsivity, and thus its photosensitivity. In addition, it can virtually boost the pixel fill factor (FF) above the 100% classical limit due to decoupling of its vertical sensing area from its limited planar circuitry area. Furthermore, the suggested nanorod photodiode photosensitivity is analytically proven to be higher than that of the planar photodiode. We also show semi-empirically that the responsivity of the suggested device varies linearly with its height; this important feature has been confirmed using Sentaurus simulation. The proposed nano-photorod is believed to meet the increasingly stringent High-Resolution-Low-Light (HRLL) detection requirements of the camera-phone and biomedical imaging markets. © 2011 IEEE.

Manifold learning based ECG-free free-breathing cardiac CINE MRI.

Science.gov (United States)

Usman, Muhammad; Atkinson, David; Kolbitsch, Christoph; Schaeffter, Tobias; Prieto, Claudia

2015-06-01

To present and validate a manifold learning (ML)-based method that can estimate both cardiac and respiratory navigator signals from electrocardiogram (ECG)-free free-breathing cardiac magnetic resonance imaging (MRI) data to achieve self-gated retrospective CINE reconstruction. In this work the use of the ML method is demonstrated for 2D cardiac CINE to achieve both cardiac and respiratory self-gating without the need of an external navigator or ECG signal. This is achieved by sequentially applying ML to two sets of retrospectively reconstructed real-time images with differing temporal resolutions. A 1D cardiac signal is estimated by applying ML to high temporal resolution real-time images reconstructed from the acquired data. Using the estimated cardiac signal, a 1D respiratory signal was obtained by applying the ML method to low temporal resolution images reconstructed from the same acquired data for each cardiac cycle. Data were acquired in five volunteers with a 2D golden angle radial trajectory in a balanced steady-state free precession (b-SSFP) acquisition. The accuracy of the estimated cardiac signal was calculated as the standard deviation of the temporal difference between the estimated signal and the recorded ECG. The correlation between the estimated respiratory signal and standard pencil beam navigator signal was evaluated. Gated CINE reconstructions (20 cardiac phases per cycle, temporal resolution ∼30 msec) using the estimated cardiac and respiratory signals were qualitatively compared against conventional ECG-gated breath-hold CINE acquisitions. Accurate cardiac signals were estimated with the proposed method, with an error standard deviation in comparison to ECG lower than 20 msec. Respiratory signals estimated with the proposed method achieved a mean cross-correlation of 94% with respect to standard pencil beam navigator signals. Good quality visual scores of 2.80 ± 0.45 (scores from 0, bad, to 4, excellent quality) were observed for the