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1

High-Resolution Autoradiography  

NASA Technical Reports Server (NTRS)

This investigation was made to adapt wet-process autoradiography to metallurgical samples to obtain high resolution of segregated radioactive elements in microstructures. Results are confined to development of the technique, which was perfected to a resolution of less than 10 microns. The radioactive samples included carbon-14 carburized iron and steel, nickel-63 electroplated samples, a powder product containing nickel-63, and tungsten-185 in N-155 alloy.

Towe, George C; Gomberg, Henry J; Freemen, J W

1955-01-01

2

High Resolution Quantitative Auto-Radiography to determine microscopic distributions of B-10 in neutron capture therapy  

E-print Network

The success of Boron Neutron Capture Therapy (BNCT) is heavily dependent on the microscopic distribution of B-10 in tissue. High Resolution Quantitative Auto-Radiography (HRQAR) is a potentially valuable analytical tool ...

Harris, Thomas C. (Thomas Cameron)

2006-01-01

3

Light microscopic localization of angiotensin II binding sites in canine medulla using high resolution autoradiography.  

PubMed

Angiotensin II (Ang II) produces dose-related, site-specific cardiovascular effects in the canine and rat dorsal medulla. Our previous studies suggested that Ang II binding sites are associated with presynaptic vagal afferent fibers in the nucleus tractus solitarii (nTS) and vagal efferent neurons in the dorsal motor nucleus of the vagus (dmnX). High resolution autoradiography now establishes the relationship of putative Ang II receptors to the cytoarchitecture of these nuclei. Sections of the canine medulla oblongata were processed for film or emulsion autoradiography with 0.3-1 nM 125I-Ang II. Quantitative densitometry of films before and after processing sections for emulsion coating confirmed no selective alteration in labeling. In emulsion coated sections, dense labeling was seen over the majority of the large perikarya and surrounding neuropil in the ventral dmnX. Bands of label overlaid vagal efferent fibers coursing ventrolaterally to exit the medulla. In the nTS, Ang II binding was restricted to regions with heavy vagal afferent innervation. In the dorsal nTS, label was distributed over both cell bodies and neuropil, with highest density capping the solitary tract. In the medial nTS, label was concentrated over perikarya, with scattered grains over the intervening neuropil. The discrete subnuclear association of Ang II binding sites in the dorsal medulla with vagal cells and fibers documents that Ang II receptors are present on both afferent vagal fibers and intrinsic medullary neurons, and reveals an anatomical substrate for the autonomic effects of Ang II in this region. PMID:1473015

Szigethy, E M; Barnes, K L; Diz, D I

1992-12-01

4

Recent technologic developments on high-resolution beta imaging systems for quantitative autoradiography and double labeling applications  

Microsoft Academic Search

Two novel beta imaging systems, particularly interesting in the field of radiopharmacology and molecular biology research, were developed these last years. (1) a beta imager was derived from research conducted by Pr Charpak at CERN. This parallel plate avalanche chamber is a direct detection system of ? radioactivity, which is particularly adapted for qualitative and quantitative autoradiography. With this detector,

N. Barthe; K. Chatti; P. Coulon; B. Basse-Cathalinat

2004-01-01

5

High resolution track etch autoradiography  

DOEpatents

A detector assembly is disclosed for use in obtaining alpha-track autoradiographs, the detector assembly including a substantially boron-free substrate; a detector layer deposited on the substantially boron-free substrate, the detector layer being capable of recording alpha particle tracks and exhibiting evidence of the alpha tracks in response to being exposed to an etchant, the detector layer being less than about 2 microns thick; and a protective layer deposited on the detector layer, the protective layer being resistant to the etchant and having a thickness of about 0.5 to 1 microns. 13 figures.

Solares, G.; Zamenhof, R.G.

1994-12-27

6

Real-time quantitative ex vivo direct autoradiography with 10 ?m pixel resolution.  

PubMed

We present three new autoradiography methods to map positron emission rate of a bio-specimen slice with high resolution. One is based on LBNL scientific charge coupled device (CCD) and the other two are based on conventional CCDs. High conversion efficiency (100k e-h pairs / 0.5 MeV positron) and low dark current (1.75 10(-4) e-/pix/sec) can be achieved using the LBNL CCD. The theoretical calculations and preliminary experiments show that an 86 ?m spatial resolution can be achieved when imaging a 100 ?m thick tissue soaked with (18)F which produce higher energy positron. The main disadvantage of the LBNL CCD we tested is that a very low operating temperature is required to eliminate dark current. This dramatically increases the system cost. In addition, the integration time of the CCD needs to be short enough to avoid overlapping of the positron trajectories. Conventional CCDs have lower conversion efficiency (2k e-h pairs / 0.5 MeV positron) and higher dark current (200 e-/pix/sec), but are more cost-efficient and the requirement for the readout frequency is much lower. The conversion efficiency of the conventional CCD imager can be improved by 17 times by inserting a 100 ?m layer of phosphor between the sample and the imager. However, the light emitted from the phosphor screen will be ~100 ?m diameter, which severely degrades the spatial resolution. A high readout frequency is also required to avoid the overlapping. The CCD systems designed in this study will be used to map positron emission rate of bio-specimens such as cancerous tissues acquired in regular biopsy procedure. They can also be used to corroborate tracer kinetic modeling at a cellular level. PMID:22255772

Peng, Q; Holland, S E; Choong, W S; Budinger, T F; Moses, W W

2011-01-01

7

Resolution-limiting factors in 2-deoxyglucose autoradiography. I. Factors other than diffusion.  

PubMed

We measured the extent to which factors other than the diffusion of the radioactive label during tissue preparation limits the spatial resolving power of 2-deoxyglucose (2-DG) autoradiography. Radioactive swept frequency gratings were created using microcircuit lithography. The gratings consisted of alternating equal width radioactive and non-radioactive bars in groups of narrowing bar width (effective range 500-20 mum). The vertical thickness of the gratings ranged from 2.25 to 20 mum. The isotope in the radioactive bars was either 14C or 3H. A variety of X-ray films were exposed to these gratings and the resulting images scanned with microdensitometers or video digitizers to determine the fall off in image contrast (dark-bar values minus light-bar values) as a function of the number of dark bars (lines) per millimeter. The power of the isotope was the resolution limiting factor. Grating thickness and type of film made little difference. The limit of resolution with 14C was 10 lines/mm; with 3H, it was 25 lines/mm. The microdensitometer itself is apt to be a resolution limiting factor; the resolving power of those commonly used in autoradiography is unlikely to exceed 10 lines/mm. From measurements of the steepness of gray-matter to white-matter transitions in the image from a tissue section, we conclude that the resolution in the image is no worse than 1.6-3.2 lines/mm. Either the isotope or diffusion of the 2-DG during tissue preparation must be the factor that limits resolution. PMID:6871678

Gallistel, C R; Nichols, S

1983-05-16

8

Whole-body and microscopic autoradiography to determine tissue distribution of biopharmaceuticals -- target discoveries with receptor micro-autoradiography engendered new concepts and therapies for vitamin D.  

PubMed

Information about the distribution of biopharmaceuticals is basic for understanding their actions. Tissue and cellular localization is a key to function. Autoradiography with radiolabeled compounds has provided valuable information with both low resolution whole-body macro-autoradiography and high resolution microscopic autoradiography (micro-autoradiography). Whole-body macro-autoradiography is a uniform and expedient single method approach, providing convenient dose- and time-related overviews with data similar to those obtained with conventional bioassays - and therefore widely used. However, whole-body macro-autoradiography, like common bioassays, has limitations. High specificity-low capacity sites of binding and deposition frequently remain unrecognized. Lack of cellular resolution can cause false negatives and provide misleading results (e.g., false blood-brain barrier). For micro-autoradiography, different methods are advertised in the literature. Most of them are, however, unsuited for drug localization because of inadequate resolution and frequent artifacts. Most drugs interact with their receptors non-covalently by weak electrostatic forces. Therefore, translocation and loss can occur during tissue preparation. This has complicated the use of micro-autoradiography. Receptor micro-autoradiography has overcome these complications and is a method of choice. It has been validated through several diffusible compounds with known localization, extensively applied. It has contributed numerous discoveries, followed by new concepts and therapies. Pictorial evidence in this review indicates that cellular information is essential, a 'sine qua non' for meaningful drug distribution studies. High resolution cellular microscopic information obtained from autoradiography requires tissue dissection and the necessary precautions for preserving pristine in vivo drug deposition. Receptor micro-autoradiography fulfils these requirements. It reveals crucial information at the subcellular level that cannot currently be obtained with any other type of autoradiography or spectrometric imaging. PMID:23391491

Stumpf, Walter E

2013-07-01

9

Analytical autoradiography  

Microsoft Academic Search

Autoradiography techniques applied in the field of material technology are discussed. Consideration is given to the choice of radionuclides introduced into or induced in the analyzed materials as well as the methods involved, the nuclear reactions taking place, and the methods for the detection of ionizing particles. Examples are presented of the application of the method, including studies of the

Iu. F. Babikova; A. A. Gusakov; V. M. Minaev; G. G. Riabova

1985-01-01

10

Skin research and drug localization with receptor microscopic autoradiography  

Microsoft Academic Search

For the localization of drugs and related functional characterization, cellular-subcellular resolution can be achieved with radiolabelled compounds of high specific activity and receptor microscopic autoradiography, which is the method of choice for high-resolution qualitative and quantitative imaging. Detailed information together with integrative surveys can be obtained which is impossible with other methods. The history of discoveries of drug targets testifies

Walter E. Stumpf; Naohiko Hayakawa; Hans-Juergen Bidmon

2007-01-01

11

High-Resolution Paleoclimatology  

Microsoft Academic Search

\\u000a High resolution paleoclimatology involves studies of natural archives as proxies for past climate variations at a temporal\\u000a scale that is comparable to that of instrumental data. In practice, this generally means annually resolved records, from tree\\u000a rings, ice cores, banded corals, laminated speleothems and varved sediments. New analytical techniques offer many unexplored\\u000a avenues of research in high resolution paleoclimatology. However,

Raymond S. Bradley

12

Quantitative receptor autoradiography  

SciTech Connect

Quantitative receptor autoradiography addresses the topic of technical and scientific advances in the sphere of quantitative autoradiography. The volume opens with a overview of the field from a historical and critical perspective. Following is a detailed discussion of in vitro data obtained from a variety of neurotransmitter systems. The next section explores applications of autoradiography, and the final two chapters consider experimental models. Methodological considerations are emphasized, including the use of computers for image analysis.

Boast, C.A.; Snowhill, E.W.; Altar, C.A.

1986-01-01

13

Effects of high-dose fenfluramine treatment on monoamine uptake sites in rat brain: assessment using quantitative autoradiography.  

PubMed

Fenfluramine is an amphetamine derivative that in humans is used primarily as an anorectic agent in the treatment of obesity. In rats, subchronic high-dose d,l-fenfluramine treatment (24 mg/kg subcutaneously, twice daily for 4 days) causes long-lasting decreases in brain serotonin (5HT), its metabolite 5-hydroxyindoleacetic acid, and high-affinity 5HT uptake sites. Moreover, this high-dose treatment regimen causes both selective long-lasting decreases in fine-caliber 5HT-immunoreactive axons and appearance of other 5HT-immunoreactive axons with morphology characteristic of degenerating axons. Determination of the potential neurotoxic effects of fenfluramine treatment using immunohistochemistry is limited from the perspectives that staining is difficult to quantify and that it relies on presence of the antigen (in this case 5HT), and the 5HT-depleting effects of fenfluramine are well known. In the present study, we used quantitative in vitro autoradiography to assess, in detail, the density and regional distribution of [3H]paroxetine-labeled 5HT and [3H]mazindol-labeled catecholamine uptake sites in response to the high-dose fenfluramine treatment described above. Because monoamine uptake sites are concentrated on monoamine-containing nerve terminals, decreases in uptake site density would provide a quantitative assessment of potential neurotoxicity resulting from this fenfluramine treatment regimen. Marked decreases in densities of [3H]paroxetine-labeled 5HT uptake sites occurred in brain regions in which fenfluramine treatment decreased the density of 5HT-like immunostaining when compared to saline-treated control rats. These included cerebral cortex, caudate putamen, hippocampus, thalamus, and medial hypothalamus. Smaller, but nonetheless significant, decreases in density of [3H]paroxetine-labeled 5HT uptake sites were noted in brain regions in which partial sparing of 5HT-like immunoreactive fibers had been reported following fenfluramine treatment, specifically septum, lateral hypothalamus, and amygdala. In contrast, [3H]mazindol autoradiography revealed that total catecholamine (i.e., dopamine and norepinephrine) uptake sites in cerebral cortex, caudate putamen, and locus coeruleus, areas in which [3H]paroxetine-labeled 5HT uptake sites were significantly decreased, were unaffected by this fenfluramine treatment. These data support the hypothesis that subchronic, high-dose fenfluramine treatment causes selective degeneration of 5HT axons in rat brain. Since pharmacokinetic studies show that the dosing regimen used in this study exposes rat brain to concentrations of fenfluramine that are approximately 600 times greater than those resulting from the therapeutic oral dose, caution must be exercised in extrapolating these data to humans. PMID:2144664

Appel, N M; Mitchell, W M; Contrera, J F; De Souza, E B

1990-01-01

14

High resolution drift chambers  

SciTech Connect

High precision drift chambers capable of achieving less than or equal to 50 ..mu..m 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.

Va'vra, J.

1985-07-01

15

Effects of high-dose fenfluramine treatment on monoamine uptake sites in rat brain: Assessment using quantitative autoradiography  

SciTech Connect

Fenfluramine is an amphetamine derivative that in humans is used primarily as an anorectic agent in the treatment of obesity. In rats, subchronic high-dose d,l-fenfluramine treatment (24 mg/kg subcutaneously, twice daily for 4 days) causes long-lasting decreases in brain serotonin (5HT), its metabolite 5-hydroxyindoleacetic acid, and high-affinity 5HT uptake sites. Moreover, this high-dose treatment regimen causes both selective long-lasting decreases in fine-caliber 5HT-immunoreactive axons and appearance of other 5HT-immunoreactive axons with morphology characteristic of degenerating axons. Determination of the potential neurotoxic effects of fenfluramine treatment using immunohistochemistry is limited from the perspectives that staining is difficult to quantify and that it relies on presence of the antigen (in this case 5HT), and the 5HT-depleting effects of fenfluramine are well known. In the present study, we used quantitative in vitro autoradiography to assess, in detail, the density and regional distribution of (3H)paroxetine-labeled 5HT and (3H)mazindol-labeled catecholamine uptake sites in response to the high-dose fenfluramine treatment described above. Because monoamine uptake sites are concentrated on monoamine-containing nerve terminals, decreases in uptake site density would provide a quantitative assessment of potential neurotoxicity resulting from this fenfluramine treatment regimen. Marked decreases in densities of (3H)paroxetine-labeled 5HT uptake sites occurred in brain regions in which fenfluramine treatment decreased the density of 5HT-like immunostaining when compared to saline-treated control rats. These included cerebral cortex, caudate putamen, hippocampus, thalamus, and medial hypothalamus.

Appel, N.M.; Mitchell, W.M.; Contrera, J.F.; De Souza, E.B. (NIDA Addiction Research Center, Baltimore, MD (USA))

1990-01-01

16

High-Resolution Lorentz Microscopy  

Microsoft Academic Search

High-resolution Lorentz micrographs of magnetic films can be obtained with a commercial electron microscope if it is properly modified. A high-resolution picture of a cross-tie wall is presented as an example of such micrographs.

Mitchell S. Cohen; K. J. HARTE

1968-01-01

17

High resolution ultrasonic densitometer  

NASA Astrophysics Data System (ADS)

The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indiction, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks.

Dress, W. B.

1983-11-01

18

High resolution ultrasonic densitometer  

SciTech Connect

The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks.

Dress, W.B.

1983-01-01

19

High resolution ultrasonic densitometer  

SciTech Connect

The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. Methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid are examined. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks.

Dress, W.B.

1983-01-01

20

High resolution time interval meter  

DOEpatents

Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

Martin, A.D.

1986-05-09

21

High Resolution Doppler Imager  

NASA Technical Reports Server (NTRS)

This report summarizes the accomplishments of the High Resolution Doppler Imager (HRDI) on UARS spacecraft during the period 4/l/96 - 3/31/99. During this period, HRDI operation, data processing, and data analysis continued, and there was a high level of vitality in the HRDI project. The HRDI has been collecting data from the stratosphere, mesosphere, and lower thermosphere since instrument activation on October 1, 1991. The HRDI team has stressed three areas since operations commenced: 1) operation of the instrument in a manner which maximizes the quality and versatility of the collected data; 2) algorithm development and validation to produce a high-quality data product; and 3) scientific studies, primarily of the dynamics of the middle atmosphere. There has been no significant degradation in the HRDI instrument since operations began nearly 8 years ago. HRDI operations are fairly routine, although we have continued to look for ways to improve the quality of the scientific product, either by improving existing modes, or by designing new ones. The HRDI instrument has been programmed to collect data for new scientific studies, such as measurements of fluorescence from plants, measuring cloud top heights, and lower atmosphere H2O.

Hays, Paul B.

1999-01-01

22

Betacam: a commercial approach to ?-autoradiography  

NASA Astrophysics Data System (ADS)

Autoradiography is a well established imaging modality in Biology and Medicine. This aims to measure the location and concentration of labelled molecules within thin tissue sections. The brain is the most anatomically complex organ and identification of neuroanatomical structures is still a challenge particularly when small animals are used for pre-clinical trials. High spatial resolution and high sensitivity are therefore necessary. This work shows the performance and ability of a prototype commercial system, based on a Charged-Couple Device (CCD), to accurately obtain detailed functional information in brain Autoradiography. The sample is placed in contact with the detector enabling direct detection of ?- particles in silicon, and the system is run in a range of quasi-room temperatures (17-22 C) under stable conditions by using a precision temperature controller. Direct detection of ?- particles with low energy down to ~5 keV from 3[H] is possible using this room temperature approach. The CCD used in this work is an E2V CCD47-20 frame-transfer device which removes the image smear arising in conventional full-frame imaging devices. The temporal stability of the system has been analyzed by exposing a set of 14[C] calibrated microscales for different periods of time, and measuring the stability of the resultant sensitivity and background noise. The thermal performance of the system has also been analyzed in order to demonstrate its capability of working in other life science applications, where higher working temperatures are required. Once the performance of the system was studied, a set of experiments with biological samples, labelled with typical ?- radioisotopes, such as 3[H], has been carried out to demonstrate its application in life sciences.

Cabello, J.; Holland, A.; Holland, K.; Bailey, A.; Kitchen, I.; Wells, K.

2009-02-01

23

High resolution telescope  

DOEpatents

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activites. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

Massie, Norbert A. (San Ramon, CA); Oster, Yale (Danville, CA)

1992-01-01

24

Gravitational instability with high resolution  

NASA Technical Reports Server (NTRS)

A series of very high resolution simulations have been performed for gravitational clustering in two dimensions. It is shown that mass resolution, achieved by having large numbers of particles, is as important as spatial resolution. New objects arising inside pancakes are found, which are coherent with structure on much larger scales. The evolution of structure in hierarchical clustering models with a sufficiently flat power spectrum includes pancake-like structures, confirming the presence of filaments in cold dark matter universes.

Melott, Adrian L.; Shandarin, Sergei F.

1989-01-01

25

A high resolution TDC subsystem  

Microsoft Academic Search

A high resolution TDC subsystem was developed at the Institute for Nuclear Physics in Mainz. The TDC chip offers a time resolution of less than 300 ps and a programmable measurement range from O to 16 ?sec. The time measurement is done with a new, purely digital counting method. The chip can be operated in common start or common stop

R. Geiges; K. Merle

1994-01-01

26

Double label autoradiography--an improvement  

SciTech Connect

A convenient method for double-label autoradiography is described that uses an aqueous mountant, Gelutol (polyvinyl alcohol), which keeps the gelatin spacer in the final autoradiograph permanently swollen to a thickness of around 18 microns in contrast to its 5 microns thickness during exposure of the autoradiograph. This greatly improves optical discrimination between upper and lower layers without the loss of sensitivity or resolution that would result if a 18 microns spacer were used during exposure.

Wynford-Thomas, D.; LaMontagne, A.; Prescott, D.M.

1986-10-01

27

High resolution underwater acoustic imaging  

Microsoft Academic Search

A high resolution underwater imaging system using sparse array technology has been developed and tested in turbid waters around Australia. High resolution 3D imaging implies many voxels. The present system can image 103103410 3 voxels although faster images can be obtained by zooming to a smaller volume of interest. With 3D images, precise dimensions of complex shapes such as pipe

I. S. F. Jones

1999-01-01

28

High resolution, high speed ultrahigh vacuum microscopy  

Microsoft Academic Search

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

Helmut Poppa

2004-01-01

29

Enhanced High Resolution RBS System  

SciTech Connect

Improvements in full spectrum resolution with the second NEC high resolution RBS system are summarized. Results for 50 A ring TiN/HfO films on Si yielding energy resolution on the order of 1 keV are also presented. Detector enhancements include improved pulse processing electronics, upgraded shielding for the MCP/RAE detector, and reduced noise generated from pumping. Energy resolution measurements on spectra front edge coupled with calculations using 0.4mStr solid angle show that beam energy spread at 400 KeV from the Pelletron registered accelerator is less than 100 eV. To improve user throughput, magnet control has been added to the automatic data collection. Depth profiles derived from experimental data are discussed. For the thin films profiled, depth resolutions were on the Angstrom level with the non-linear energy/channel conversions ranging from 100 to 200 eV.

Pollock, Thomas J.; Hass, James A.; Klody, George M. [National Electrostatics Corp., Middleton, Wisconsin, U. S. A. 53562-0310 (United States)

2011-06-01

30

High Resolution Doppler Lidar  

NASA Technical Reports Server (NTRS)

This Grant supported the development of an incoherent lidar system to measure winds and aerosols in the lower atmosphere. During this period the following activities occurred: (1) an active feedback system was developed to improve the laser frequency stability; (2) a detailed forward model of the instrument was developed to take into account many subtle effects, such as detector non-linearity; (3) a non-linear least squares inversion method was developed to recover the Doppler shift and aerosol backscatter without requiring assumptions about the molecular component of the signal; (4) a study was done of the effects of systematic errors due to multiple etalon misalignment. It was discovered that even for small offsets and high aerosol loadings, the wind determination can be biased by as much as 1 m/s. The forward model and inversion process were modified to account for this effect; and (5) the lidar measurements were validated using rawinsonde balloon measurements. The measurements were found to be in agreement within 1-2 m/s.

1996-01-01

31

Berkeley High-Resolution Ball  

SciTech Connect

Criteria for a high-resolution ..gamma..-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 ..gamma..-ray energy and multiplicity, as well as the angular pattern of the ..gamma.. 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 /sup 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.

Diamond, R.M.

1984-10-01

32

Using high resolution displays for high resolution cardiac data  

E-print Network

, and annotation, focusing on two datasets from a project addressing the individual histo-anatomy of a rabbit heart, UK Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK display of data from high resolution MRI scanning of a rabbit heart and subsequent histolog- ical imaging

Brodlie, Ken

33

High resolution radar clutter statistics  

Microsoft Academic Search

The generalized compound probability density function (GC-pdf) is presented for modeling high resolution radar clutter. In particular, the model is used to describe deviation of the speckle component from the Rayleigh to Weibull or other pdfs with longer tails. The GC-pdf is formed using the generalized gamma (G?) pdf to describe both the speckle and the modulation component of the

V. ANASTASSOPOULOS; G. A. Lampropoulos; A. Drosopoulos; N. Rey

1999-01-01

34

Advanced very high resolution radiometer  

NASA Technical Reports Server (NTRS)

The advanced very high resolution radiometer development program is considered. The program covered the design, construction, and test of a breadboard model, engineering model, protoflight model, mechanical structural model, and a life test model. Special bench test and calibration equipment was also developed for use on the program.

1976-01-01

35

High resolution optical DNA mapping  

NASA Astrophysics Data System (ADS)

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.

Baday, Murat

36

High-resolution color images of Io  

NASA Technical Reports Server (NTRS)

Color versions of the highest resolution Voyager images of Io were produced by combining the low resolution color images with the high resolution, clear filter images. High resolution versions of the orange, blue, and violet filter images are produced by: orange = high-res clear * low-res orange / low-res clear blue = high-res clear * low-res blue / low-res clear violet = high-res clear * low-res violet / low-res clear. The spectral responses of the high and low resolution clear filter images cancel, leaving the color, while the spatial frequencies of the two low resolution images cancel, leaving the high resolution.

Mcewen, A. S.; Soderblom, L. A.

1984-01-01

37

High resolution tomographic instrument development  

SciTech Connect

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.

Not Available

1992-08-01

38

High resolution tomographic instrument development  

SciTech Connect

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.

Not Available

1992-01-01

39

High Resolution Scanning Reflectarray Antenna  

NASA Technical Reports Server (NTRS)

The present invention provides a High Resolution Scanning Reflectarray Antenna (HRSRA) for the purpose of tracking ground terminals and space craft communication applications. The present invention provides an alternative to using gimbaled parabolic dish antennas and direct radiating phased arrays. When compared to a gimbaled parabolic dish, the HRSRA offers the advantages of vibration free steering without incurring appreciable cost or prime power penalties. In addition, it offers full beam steering at a fraction of the cost of direct radiating arrays and is more efficient.

Romanofsky, Robert R. (Inventor); Miranda, Felix A. (Inventor)

2000-01-01

40

High-Resolution Imaging Spectrometer  

NASA Technical Reports Server (NTRS)

Earth resources observed in greater detail. High-Resolution Imaging Spectrometer, undergoing development for use in NASA's Earth Observing System, measures reflectance of Earth's surface in visible and near-infrared wavelengths. From an orbit around Earth, instrument scans surface of Earth in 200 wavelength bands simultaneously. Produces images enabling identification of minerals in rocks and soils, important algal pigments in oceans and inland waters, changes in spectra associated with biochemistry of plant canopies, compositions of atmospheric aerosols, sizes of grains in snow, and contamination of snow by impurities that absorb visible light.

Dozier, Jeff; Goetz, Alexander F. H.

1990-01-01

41

High resolution time interval counter  

NASA Technical Reports Server (NTRS)

In recent years, we have developed two types of high resolution, multi-channel time interval counters. In the NIST two-way time transfer MODEM application, the counter is designed for operating primarily in the interrupt-driven mode, with 3 start channels and 3 stop channels. The intended start and stop signals are 1 PPS, although other frequencies can also be applied to start and stop the count. The time interval counters used in the NIST Frequency Measurement and Analysis System are implemented with 7 start channels and 7 stop channels. Four of the 7 start channels are devoted to the frequencies of 1 MHz, 5 MHz or 10 MHz, while triggering signals to all other start and stop channels can range from 1 PPS to 100 kHz. Time interval interpolation plays a key role in achieving the high resolution time interval measurements for both counters. With a 10 MHz time base, both counters demonstrate a single-shot resolution of better than 40 ps, and a stability of better than 5 x 10(exp -12) (sigma(sub chi)(tau)) after self test of 1000 seconds). The maximum rate of time interval measurements (with no dead time) is 1.0 kHz for the counter used in the MODEM application and is 2.0 kHz for the counter used in the Frequency Measurement and Analysis System. The counters are implemented as plug-in units for an AT-compatible personal computer. This configuration provides an efficient way of using a computer not only to control and operate the counters, but also to store and process measured data.

Zhang, Victor S.; Davis, Dick D.; Lombardi, Michael A.

1995-01-01

42

High Resolution Timing with Low Resolution Clocks A Microsecond Resolution Timer for Sun Workstations  

E-print Network

High Resolution Timing with Low Resolution Clocks and A Microsecond Resolution Timer for Sun for Sun 3 and Sun 4 workstations1. One can measure average service times without a high resolution clock?" 1. Introduction - Who Needs a Microsecond Clock Beginning with its Sun 3 workstations, Sun

Melvin, Stephen

43

High resolution, high speed ultrahigh vacuum microscopy  

NASA Astrophysics Data System (ADS)

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 spectroscopy, ultraviolet photoelectron spectroscopy, Auger electron spectroscopy, low-energy electron diffraction, temperature programmed desorption, high-resolution electron energy-loss and Fourier-transform infrared spectroscopies, and others. Material systems ranging from atomic layers of metals and semiconductors to biology related depositions are being investigated. In the case of biological materials, however, strict limitations to high-resolution applications are imposed by electron radiation damage considerations.

Poppa, Helmut

2004-09-01

44

Ultra-high resolution AMOLED  

NASA Astrophysics Data System (ADS)

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 19201200 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.

Wacyk, Ihor; Prache, Olivier; Ghosh, Amal

2011-06-01

45

High-resolution slug testing.  

PubMed

The hydraulic conductivity (K) variation has important ramifications for ground water flow and the transport of contaminants in ground water. The delineation of the nature of that variation can be critical to complete characterization of a site and the planning of effective and efficient remedial measures. Site-specific features (such as high-conductivity zones) need to be quantified. Our alluvial field site in the Kansas River valley exhibits spatial variability, very high conductivities, and nonlinear behavior for slug tests in the sand and gravel aquifer. High-resolution, multilevel slug tests have been performed in a number of wells that are fully screened. A general nonlinear model based on the Navier-Stokes equation, nonlinear frictional loss, non-Darcian flow, acceleration effects, radius changes in the wellbore, and a Hvorslev model for the aquifer has been used to analyze the data, employing an automated processing system that runs within the Excel spreadsheet program. It is concluded that slug tests can provide the necessary data to identify the nature of both horizontal and vertical K variation in an aquifer and that improved delineation or higher resolution of K structure is possible with shorter test intervals. The gradation into zones of higher conductivity is sharper than seen previously, and the maximum conductivity observed is greater than previously measured. However, data from this project indicate that well development, the presence of fines, and the antecedent history of the well are important interrelated factors in regard to slug-test response and can prevent obtaining consistent results in some cases. PMID:15819943

Zemansky, G M; McElwee, C D

2005-01-01

46

Autoradiography and the Cell Cycle.  

ERIC Educational Resources Information Center

Outlines the stages of a cell biology "pulse-chase" experiment in which the students apply autoradiography techniques to learn about the concept of the cell cycle. Includes (1) seed germination and plant growth; (2) radioactive labeling and fixation of root tips; (3) feulgen staining of root tips; (4) preparation of autoradiograms; and (5)

Jones, C. Weldon

1992-01-01

47

High Resolution, High Frame Rate Video Technology  

NASA Technical Reports Server (NTRS)

Papers and working group summaries presented at the High Resolution, High Frame Rate Video (HHV) Workshop are compiled. HHV system is intended for future use on the Space Shuttle and Space Station Freedom. The Workshop was held for the dual purpose of: (1) allowing potential scientific users to assess the utility of the proposed system for monitoring microgravity science experiments; and (2) letting technical experts from industry recommend improvements to the proposed near-term HHV system. The following topics are covered: (1) State of the art in the video system performance; (2) Development plan for the HHV system; (3) Advanced technology for image gathering, coding, and processing; (4) Data compression applied to HHV; (5) Data transmission networks; and (6) Results of the users' requirements survey conducted by NASA.

1990-01-01

48

High Resolution Nanoimprint for Nanophotonics  

E-print Network

resolution fabrication technique for SERS-active devices. The objective of this research is to explore the application of nanoimprint lithography in SERS-active devices. This work begins with two issues of nanoimprint lithography: mold fabrication...

Jiang, Youwei

2014-04-28

49

FEATURE COMPILATION FROM HIGH RESOLUTION SATELLITE IMAGERY  

Microsoft Academic Search

The high quality level that high resolution satellite images have reached in the last years has proved that these images could be a useful data source for the production of orthophoto and different mapping products. To test the capabilities of high resolution imagery, a study has been implemented in Glba?i near Ankara. 12 ground control points were revised and signalized

V. O. Ataka; M. O. Altan

50

High resolution amorphous silicon radiation detectors  

DOEpatents

A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n-type, intrinsic, p-type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography. 18 figs.

Street, R.A.; Kaplan, S.N.; Perez-Mendez, V.

1992-05-26

51

High-spatial-resolution remote sensing  

Microsoft Academic Search

Recent developments in high-spatial-resolution remote sensing have created a wide array of potential new forestry applications. High spatial resolution imagery allows a tree-scale of analysis, in which individual trees and their attributes are the focus of interest. This tree-scale remote sensing contrasts with the traditional community-scale remote sensing of medium resolution sensors such as Landsat. A variety of approaches have

Tomas Brandtberg; Timothy Warner

52

Extremely high resolution fiber temperature sensor  

Microsoft Academic Search

A novel medical temperature sensor using two fiber Bragg gratings is presented. The experimental results demonstrate this sensor can employ as high as 0.01 degree(s)C resolution. It is expected that with interpolation, this sensor can achieve the resolution as high as 0.001 degree(s)C.

Shyh-Lin Tsao; Bih-Chyun Yeh

1998-01-01

53

A study of Cs-137 spatial distribution in soil thin sections by digital autoradiography  

NASA Astrophysics Data System (ADS)

Recent studies have proved autoradiography to have high potential in detection of radiation in particles including geological objects [1-3]. We applied digital autoradiography based on usage of image plates to study Cs-137 microdistribution in thin sections of the podzolic sandy soil typical for the Chernobyl remote impact zone 25 years after the accident. The zone is noted for contamination of the so-called condensation type where the contribution of the "hot" fuel particles has been comparatively low. The initial 137Cs contamination level of the study plot approximated 40 Ci/km2. According to the soil core data twenty five years after the accident the main portion of cesium radioisotopes is still concentrated in the 10-20 cm thick surface layer. Thin sections have been prepared from the top 0-10 cm soil layer of the soil profile located on the shoulder of the relatively steep northern slope of the forested hill formed on the Iput river terrace ca 20 km to the east of the town of Novozybkov, Bryansk region. Undisturbed soil sample was impregnated with epoxy resin, then dissected in vertical triplicates and polished to obtain open surface. Autoradiography of the thin sections has clearly shown different patterns of Cs-137 distribution related to its concentration in organic material and on the surface of soil particles. High sensitivity and resolution of the applied technique enables to reveal concentration and dispersion zones on microscale level. Soil micro-morphology has shown to be helpful in deciphering soil components and properties responsible for Cs-137 retention in the soil top layer. References 1. Mihoko Hareyama, Noriyoshi Tsuchiya, Masahiro Takebe and Tadashi Chida. Two-dimensional measurement of natural radioactivity of granitic rocks by photostimulated luminescence technique Geochemical Journal, 2000, 34, 1- 9. 2. Zeissler C. J., R. M. Lindstrom, J. P. McKinley. Radioactive particle analysis by digital autoradiography. Journal of Radioanalytical and Nuclear Chemistry, 2001, 248, 2, 407-412. 3. Daniel Rufer and Frank Preusser. Potential of autoradiography to detect spatially resolved radiation patterns in the context of trapped charge dating. Geochronometria, 2009, 34, 1-13.

Korobova, Elena; Dogadkin, Nikolay; Shiryaev, Andrey; Kolotov, Vladimir; Turkov, Victor

2013-04-01

54

Identifying chromatin interactions at high spatial resolution  

E-print Network

This thesis presents two computational approaches for identifying chromatin interactions at high spatial resolution from ChIA-PET data. We introduce SPROUT which is a hierarchical probabilistic model that discovers high ...

Reeder, Christopher Campbell

2014-01-01

55

Single particle analysis at high resolution.  

PubMed

Electron cryomicroscopy (cryo-EM) and single particle analysis is emerging as a powerful technique for determining the 3D structure of large biomolecules and biomolecular assemblies in close to their native solution environment. Over the last decade, this technology has improved, first to sub-nanometer resolution, and more recently beyond 0.5 nm resolution. Achieving sub-nanometer resolution is now readily approachable on mid-range microscopes with straightforward data processing, so long as the target specimen meets some basic requirements. Achieving resolutions beyond 0.5 nm currently requires a high-end microscope and careful data acquisition and processing, with much more stringent specimen requirements. This chapter will review and discuss the methodologies for determining high-resolution cryo-EM structures of nonvirus particles to sub-nanometer resolution and beyond, with a particular focus on the reconstruction strategy implemented in the EMAN software suite. PMID:20888963

Cong, Yao; Ludtke, Steven J

2010-01-01

56

Fabrication of high-resolution micropolarizer arrays  

E-print Network

, as in iodide-doped polyvinyl alcohol PVA films. For example, potassium io- dide (KI3) diffusion into stretched@echo.phs.uiuc.edu Abstract. Procedures for creating high-resolution polarization filter ar- rays using multilayer polyvinyl alcohol (PVA) films are described. Two state polarization filter arrays with 25 m resolution and three

Guo, Junpeng

57

High-Resolution Plots of Trigonometric Functions.  

ERIC Educational Resources Information Center

Provides computer programs (for Apple microcomputers) for drawing (in high resolution graphics) a three-leaved rose, concentric circles, circumscribed and inscribed astroids. Sample output and discussions of the mathematics involved in the programs are included. (JN)

Stick, Marvin E.; Stick, Michael J.

1985-01-01

58

High-Resolution X-Ray Telescopes  

NASA Technical Reports Server (NTRS)

Fundamental needs for future x-ray telescopes: a) Sharp images => excellent angular resolution. b) High throughput => large aperture areas. Generation-X optics technical challenges: a) High resolution => precision mirrors & alignment. b) Large apertures => lots of lightweight mirrors. Innovation needed for technical readiness: a) 4 top-level error terms contribute to image size. b) There are approaches to controlling those errors. Innovation needed for manufacturing readiness. Programmatic issues are comparably challenging.

ODell, Stephen L.; Brissenden, Roger J.; Davis, William; Elsner, Ronald F.; Elvis, Martin; Freeman, Mark; Gaetz, Terry; Gorenstein, Paul; Gubarev, Mikhail V.

2010-01-01

59

14C autoradiography with a novel wafer scale CMOS Active Pixel Sensor  

NASA Astrophysics Data System (ADS)

14C autoradiography is a well established technique for structural and metabolic analysis of cells and tissues. The most common detection medium for this application is film emulsion, which offers unbeatable spatial resolution due to its fine granularity but at the same time has some limiting drawbacks such as poor linearity and rapid saturation. In recent years several digital detectors have been developed, following the technological transition from analog to digital-based detection systems in the medical and biological field. Even so such digital systems have been greatly limited by the size of their active area (a few square centimeters), which have made them unsuitable for routine use in many biological applications where sample areas are typically ~ 10-100 cm2. The Multidimensional Integrated Intelligent Imaging (MI3-Plus) consortium has recently developed a new large area CMOS Active Pixel Sensor (12.8 cm 13.1 cm). This detector, based on the use of two different pixel resolutions, is capable of providing simultaneously low noise and high dynamic range on a wafer scale. In this paper we will demonstrate the suitability of this detector for routine beta autoradiography in a comparative approach with widely used film emulsion.

Esposito, M.; Anaxagoras, T.; Larner, J.; Allinson, N. M.; Wells, K.

2013-01-01

60

A high-resolution phantom for MRI.  

PubMed

Assessment of spatial resolution is an important step to test the performance of new sequence techniques-especially ultrafast techniques with dedicated k-space trajectories or interpolation algorithms. Measurement of the modulation transfer function (MTF) is a rather difficult procedure, but using suitable resolution phantoms allows a simple visual evaluation of spatial resolution. In contrast to commonly used test objects with a very restricted number of resolution patterns we developed a phantom containing resolution patterns from 0.1 to 1.5 mm in steps of 0.1 mm. One resolution pattern consists of five parallel Plexiglas strips with the distance of the strips being equal to their thickness. Together with a Plexiglas cuboid the resolution patterns are mounted on a Plexiglas plate on the bottom of the cylindrical phantom. An aqueous solution of manganese chloride is used to fill the phantom. High resolution cross sections (pixel size: 50 microm) through the resolution patterns were measured to confirm the correct dimensions of the phantom. To verify the appropriateness of the 0.1 and 0.2 mm stacks micro-CT images with a pixel size of 25 microm were acquired additionally for both patterns. Besides visual inspection evaluation of the profile function of signal intensity across the stacks demonstrates that the resolution patterns are sufficiently correct. T(1)-weighted SE sequences with slightly different pixel sizes as well as T(1)- and T(2*)- weighted gradient echo sequences were applied to demonstrate some possible applications of this phantom. In conclusion, the proposed phantom is well suited to assess the spatial resolution qualitatively (i.e., visually) and quantitatively over a wide range in steps of 0.1 mm. PMID:11551732

Fellner, C; Mller, W; Georgi, J; Taubenreuther, U; Fellner, F A; Kalender, W A

2001-07-01

61

High resolution schemes for hyperbolic conservation laws  

Microsoft Academic Search

A class of new explicit second order accurate finite difference schemes for the computation of weak solutions of hyperbolic conservation laws is presented. These highly nonlinear schemes are obtained by applying a nonoscillatory first order accurate scheme to an apppropriately modified flux function. The so-derived second order accurate schemes achieve high resolution while preserving the robustness of the original nonoscillatory

A. Harten

1983-01-01

62

High-Resolution PET Detector. Final report  

SciTech Connect

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.

Karp, Joel

2014-03-26

63

High spectral resolution reflectance spectroscopy of minerals  

USGS Publications Warehouse

The reflectance spectra of minerals are studied as a function of spectral resolution in the range from 0.2 to 3.0 ??m. Selected absorption bands were studied at resolving powers (??/????) as high as 2240. At resolving powers of approximately 1000, many OH-bearing minerals show diagnostic sharp absorptions at the resolution limit. At low resolution, some minerals may not be distinguishable, but as the resolution is increased, most can be easily identified. As the resolution is increased, many minerals show fine structure, particularly in the OH-stretching overtone region near 1.4 ??m. The fine structure can enhance the ability to discriminate between minerals, and in some cases the fine structure can be used to determine elemental composition. The study shows that high-resolution reflectance spectroscopy of minerals may prove to be a very important tool in the laboratory, in the field using field-portable spectrometers, from aircraft, and from satellites looking at Earth or other planetary surfaces. -from Authors

Clark, R.N.; King, T.V.V.; Klejwa, M.; Swayze, G.A.; Vergo, N.

1990-01-01

64

High Spatial Resolution Thermal Satellite Technologies  

NASA Technical Reports Server (NTRS)

This document in the form of viewslides, reviews various low-cost alternatives to high spatial resolution thermal satellite technologies. There exists no follow-on to Landsat 7 or ASTER high spatial resolution thermal systems. This document reviews the results of the investigation in to the use of new technologies to create a low-cost useful alternative. Three suggested technologies are examined. 1. Conventional microbolometer pushbroom modes offers potential for low cost Landsat Data Continuity Mission (LDCM) thermal or ASTER capability with at least 60-120 ground sampling distance (GSD). 2. Backscanning could produce MultiSpectral Thermal Imager performance without cooled detectors. 3. Cooled detector could produce hyperspectral thermal class system or extremely high spatial resolution class instrument.

Ryan, Robert

2003-01-01

65

High-resolution Raman scattering in oligonucleotides  

NASA Astrophysics Data System (ADS)

The high-resolution spectra of short single-stranded oligonucleotides have been measured by the high-sensitivity nonresonant Raman scattering method using the example of the system d(20 G, 20 T), where G is guanine and T is thymine. The samples under study have been prepared by the chemical synthesis using the solid-phase amidophosphite method on an automatic synthesizer. It has been shown that the spectra observed in the frequency range of 500-1500 cm-1 can be sufficient for the resolution of spectral components corresponding to vibrations of individual oligonucleotide molecules, which contain a large number of atoms in the unit cell.

Bairamov, F. B.; Poloskin, E. D.; Chernev, A. L.; Toporov, V. V.; Dubina, M. V.; Lashkul, A.; Lahderanta, E.; Lipsanen, H.; Bairamov, B. Kh.

2014-06-01

66

Single shot high resolution digital holography.  

PubMed

We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise. PMID:23481715

Khare, Kedar; Ali, P T Samsheer; Joseph, Joby

2013-02-11

67

RAPID DAMAGE ASSESSMENT FROM HIGH RESOLUTION IMAGERY  

SciTech Connect

Disaster impact modeling and analysis uses huge volumes of image data that are produced immediately following a natural or an anthropogenic disaster event. Rapid damage assessment is the key to time critical decision support in disaster management to better utilize available response resources and accelerate recovery and relief efforts. But exploiting huge volumes of high resolution image data for identifying damaged areas with robust consistency in near real time is a challenging task. In this paper, we present an automated image analysis technique to identify areas of structural damage from high resolution optical satellite data using features based on image content.

Vijayaraj, Veeraraghavan [ORNL; Bright, Eddie A [ORNL; Bhaduri, Budhendra L [ORNL

2008-01-01

68

ELECTRONICS UPGRADE OF HIGH RESOLUTION MASS SPECTROMETERS  

SciTech Connect

High resolution mass spectrometers are specialized systems that allow researchers to determine the exact mass of samples to four significant digits by using magnetic and electronic sector mass analyzers. Many of the systems in use today at research laboratories and universities were designed and built more than two decades ago. The manufacturers of these systems have abandoned the support for some of the mass spectrometers and parts to power and control them have become scarce or obsolete. The Savannah River National Laboratory has been involved in the upgrade of the electronics and software for these legacy machines. The Electronics Upgrade of High Resolution Mass Spectrometers consists of assembling high-end commercial instrumentation from reputable manufacturers with a minimal amount of customization to replace the electronics for the older systems. By taking advantage of advances in instrumentation, precise magnet control can be achieved using high resolution current sources and continuous feedback from a high resolution hall-effect probe. The custom equipment include a precision voltage divider/summing amplifier chassis, high voltage power supply chassis and a chassis for controlling the voltage emission for the mass spectrometer source tube. The upgrade package is versatile enough to interface with valve control, vacuum and other instrumentation. Instrument communication is via a combination of Ethernet and traditional IEEE-488 GPIB protocols. The system software upgrades include precision control, feedback and spectral waveform analysis tools.

Mcintosh, J; Joe Cordaro, J

2008-03-10

69

High Resolution Supply Chain Management Resolution of the polylemma of production by  

E-print Network

High Resolution Supply Chain Management ­ Resolution of the polylemma of production by information.Stich@fir.rwth-aachen.de Abstract. High Resolution Supply Chain Management (HRSCM) aims to stop the trend of continuously increasing). "High Resolution Supply Chain Management" focuses to solve the dilemma be- tween a high grade

Paris-Sud XI, Université de

70

High-resolution fiber-fed spectrographs  

Microsoft Academic Search

We analyze the properties of high-resolution spectrographs fed from the telescope through optical fiber links. We report the\\u000a results of tests performed with the fiber-fed spectrograph that we developed for 12 m telescopes.

V. E. Panchuk; M. V. Yushkin; M. V. Yakopov

2011-01-01

71

High resolution optical fiber print head  

Microsoft Academic Search

A high resolution printing head for a line printer using photographic recording medium has a plurality of modules connected to form a two dimensional printing array. Each module has three fiber optic ribbons bonded together to form a staggered array of fibers. An apertured mask is photolithographically attached to the two dimensional array so that there is one aperture positioned

M. J. Meier

1986-01-01

72

High-resolution Sidescan Sonar Towfish  

USGS Multimedia Gallery

Mikhail Malin, visiting IBIW scientist, prepares to deploy a high-resolution sidescan sonar towfish below Bagnell Dam on the Osage River. The CERC and IBIW collaborated with the Missouri Cooperative Fish and Wildlife Research Unit at the University of Missouri to assess the distribution of pad...

73

High-resolution isofield mapping in magnetocardiography  

Microsoft Academic Search

SummaryA possible clinical application of a high-resolution magnetic isofield contour mapping technique in cardiography is discussed. Preliminary results are presented in applying this technique to patients with recent myocardial infarction. The patients could be divided into two classes; one of them contains patients with electrical late potentials as a subclass.

S. N. Ern; R. R. Fenici; H.-D. Hahlbohm; W. Jaszczuk; H. P. Lehmann; M. Masselli

1983-01-01

74

High-Resolution, Two-Wavelength Pyrometer  

NASA Technical Reports Server (NTRS)

Modified two-color pyrometer measures temperatures of objects with high spatial resolution. Image focused on hole 0.002 in. (0.05 mm) in diameter in brass sheet near end of bundle, causing image to be distributed so fibers covered by defocused radiation from target. Pinhole ensures radiation from only small part of target scene reaches detector, thus providing required spatial resolution. By spreading radiation over bundle, pinhole ensures entire active area of detectors utilized. Produces signal as quiet as conventional instruments but with only 1/64 input radiation.

Bickler, Donald B.; Henry, Paul K.; Logiurato, D. Daniel

1989-01-01

75

A Portable, High Resolution, Surface Measurement Device  

NASA Technical Reports Server (NTRS)

A high resolution, portable, surface measurement device has been demonstrated to provide micron-resolution topographical plots. This device was specifically developed to allow in-situ measurements of defects on the Space Shuttle Orbiter windows, but is versatile enough to be used on a wide variety of surfaces. This paper discusses the choice of an optical sensor and then the decisions required to convert a lab bench optical measurement device into an ergonomic portable system. The necessary trade-offs between performance and portability are presented along with a description of the device developed to measure Orbiter window defects.

Ihlefeld, Curtis M.; Burns, Bradley M.; Youngquist, Robert C.

2012-01-01

76

High resolution schemes for hyperbolic conservation laws  

NASA Technical Reports Server (NTRS)

A class of new explicit second order accurate finite difference schemes for the computation of weak solutions of hyperbolic conservation laws is presented. These highly nonlinear schemes are obtained by applying a nonoscillatory first order accurate scheme to an appropriately modified flux function. The so-derived second order accurate schemes achieve high resolution while preserving the robustness of the original nonoscillatory first order accurate scheme. Numerical experiments are presented to demonstrate the performance of these new schemes.

Harten, A.

1983-01-01

77

Constructing a WISE High Resolution Galaxy Atlas  

NASA Technical Reports Server (NTRS)

After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 micron, 4.6 micron, 12 micron, and 22 micron. We have begun a dedicated WISE High Resolution Galaxy Atlas project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we summarize the deconvolution techniques used to significantly improve the spatial resolution of WISE imaging, specifically designed to study the internal anatomy of nearby galaxies. As a case study, we present results for the galaxy NGC 1566, comparing the WISE enhanced-resolution image processing to that of Spitzer, Galaxy Evolution Explorer, and ground-based imaging. This is the first paper in a two-part series; results for a larger sample of nearby galaxies are presented in the second paper.

Jarrett, T. H.; Masci, F.; Tsai, C. W.; Petty, S.; Cluver, M.; Assef, Roberto J.; Benford, D.; Blain, A.; Bridge, C.; Donoso, E.; Eisenhardt, P.; Fowler, J.; Koribalski, B.; Lake, S.; Neill, James D.; Seibert, M.; Stanford, S.; Wright, E.

2012-01-01

78

HIRIS - The High Resolution Imaging Spectrometer  

NASA Technical Reports Server (NTRS)

The High-Resolution Imaging Spectrometer (HIRIS) is a JPL facility instrument designed for NASA's Earth Observing System (Eos).It will have 10-nm wide spectral bands from 0.4-2.5 microns at 30 m spatial resolution over a 30 km swath. The spectral resolution allows identification of many minerals in rocks and soils, important algal pigments in oceans and inland waters, spectral changes associated with plant canopy biochemistry, composition of atmospheric aerosols, and grain size of snow and its contamination by absorbing impurities. The bands wil have 12-bit quantization over a dynamic range suitable for bright targets, such as snow. For targets of low brightness, such as water bodies, image-motion compensation will allow gains up to a factor of eight to increase signal-to-noise ratios. In the 824-km orbit altitude proposed for Eos, the crosstrack pointing capability will allow 4-5 views during a 16-day revisit cycle.

Dozier, Jeff

1988-01-01

79

High-resolution reconstruction for terahertz imaging.  

PubMed

We present a high-resolution (HR) reconstruction model and algorithms for terahertz imaging, taking advantage of super-resolution methodology and algorithms. The algorithms used include projection onto a convex sets approach, iterative backprojection approach, Lucy-Richardson iteration, and 2D wavelet decomposition reconstruction. Using the first two HR reconstruction methods, we successfully obtain HR terahertz images with improved definition and lower noise from four low-resolution (LR) 2224 terahertz images taken from our homemade THz-TDS system at the same experimental conditions with 1.0mm pixel. Using the last two HR reconstruction methods, we transform one relatively LR terahertz image to a HR terahertz image with decreased noise. This indicates potential application of HR reconstruction methods in terahertz imaging with pulsed and continuous wave terahertz sources. PMID:25607865

Xu, Li-Min; Fan, Wen-Hui; Liu, Jia

2014-11-20

80

High-Resolution Photoelectron and Photoionization Spectroscopy  

NASA Astrophysics Data System (ADS)

Since its development in the late 1950s and early 1960s, photoelectron spectroscopy has established itself as an important method to study the electronic structure of molecules, their photoionization dynamics, and the structure and dynamics of molecular cations. In recent years, and particularly since the development of pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectroscopy, considerable progress has been made in the resolution that can be achieved by photoelectron spectroscopy. This progress relies on the systematic exploitation of the unusual physical properties of high Rydberg states and enables one today to resolve the rotational structure in the photoelectron spectra of even large molecules and the hyperfine structure in the photoelectron spectra of small molecules. This talk will begin with a brief historical review of photoelectron spectroscopy. Then, the relationship between photoelectron spectroscopy, photoionization spectroscopy and the spectroscopy of high Rydberg states will be discussed. It will be explained how this relationship is currently exploited to improve the resolution achievable by PFI-ZEKE photoelectron spectroscopy. Then, the physical principles that are at the heart of the latest methods related to high-resolution photoelectron spectroscopy will be described together with their fundamental limitations. Depending on the resolution and the spectral range needed to address a specific scientific problem, a choice can be made between several different methods with spectral resolutions ranging from 30 GHz to better than 1 MHz. The talk will summarize the current state of the art in gas-phase photoelectron spectroscopy and be illustrated by several examples, primarily taken from the research in my group, in which photoelectron spectroscopy has contributed to answer questions concerning the structure and dynamics of small-sized molecular cations. F. I. Vilesov, B. C. Kurbatov, and N. Terrenin, Soviet Phys. (Doklady) 6, 490 (1961) D. W. Turner and M. I. Al-Jobory, J. Chem. Phys. 37, 3007 (1962) G. Reiser, W. Habenicht, K. Mller-Dethlefs and E. W. Schlag, Chem. Phys. Lett. 152, 119 (1988) F. Merkt, S. Willitsch and U. Hollenstein, High-resolution photoelectron spectroscopy, in: Handbook of high-resolution spectroscopy, eds. M. Quack and F. Merkt (Wiley, Chichester, 2011), Vol. III, pp 1617-1654

Merkt, F.

2012-06-01

81

High resolution, large area, high energy x-ray tomography  

SciTech Connect

An x-ray tomography system is being developed for high resolution inspection of large objects. The goal is to achieve 25 micron resolution over object sizes that are tens of centimeters in extent. Typical objects will be metal in composition and therefore high energy, few MeV x-rays will be required. A proof-of-principle system with a limited field of view has been developed. Preliminary results are presented.

Trebes, J.E.; Dolan, K.W.; Haddad, W.S.; Haskins, J.J.; Lerche, R.A.; Logan, C.M.; Perkins, D.E.; Schneberk, D.J.; Rikard, R.D.

1997-08-01

82

High-resolution flurescence spectroscopy in immunoanalysis  

SciTech Connect

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.

Grubor, Nenad M.

2005-05-01

83

High Resolution Two-Dimensional Electrophoresis of Proteins*  

PubMed Central

Summary A technique has been developed for the separation of proteins by two-dimensional polyacrylamide gel electrophoresis. Due to its resolution and sensitivity, this technique is a powerful tool for the analysis and detection of proteins from complex biological sources. Proteins are separated according to isoelectric point by isoelectric focusing in the first dimension, and according to molecular weight by sodium dodecyl sulfate electrophoresis in the second dimension. Since these two parameters are unrelated, it is possible to obtain an almost uniform distribution of protein spots across a two-dimensional gel. This technique has resolved 1100 different components from Escherichia coli and should be capable of resolving a maximum of 5000 proteins. A protein containing as little as one disintegration per min of either 14C or 35S can be detected by autoradiography. A protein which constitutes 10?4 to 10?5% of the total protein can be detected and quantified by autoradiography. The reproducibility of the separation is sufficient to permit each spot on one separation to be matched with a spot on a different separation. This technique provides a method for estimation (at the described sensitivities) of the number of proteins made by any biological system. This system can resolve proteins differing in a single charge and consequently can be used in the analysis of in vivo modifications resulting in a change in charge. Proteins whose charge is changed by missense mutations can be identified. A detailed description of the methods as well as the characteristics of this system are presented. PMID:236308

O'Farrell, Patrick H.

2010-01-01

84

New high resolution solar telescope GREGOR  

Microsoft Academic Search

The 1.5m solar telescope GREGOR is being constructed at Tenerife, Spain. Its purpose is to observe with high spatial and spectral resolution small-scale dynamic magnetic features on the Sun. The telescope is completely open with retractable dome and actively cooled primary mirror made of silicon carbide to minimize thermal effects on the image quality. After completion it will be one

R. Volkmer; O. von der Lhe; F. Kneer; J. Staude; H. Balthasar; T. Berkefeld; P. Caligari; M. Collados; C. Halbgewachs; F. Heidecke; A. Hofmann; M. Klvaa; M. Sobotka; H. Nicklas; E. Popow; K. G. Puschmann; W. Schmidt; D. Soltau; K. Strassmeier; A. D. Wittmann

2007-01-01

85

High-resolution spectroscopy of M subdwarfs  

NASA Astrophysics Data System (ADS)

We present a UVES/VLT high-resolution spectroscopic analysis of M subdwarfs (sdM), which have opacities different from those of normal dwarfs. Our atlas covers the optical region from 6400 up to the near infrared at 9000 . We present spectral details of cool atmospheres at very high-resolution (R 40 000) and compare the spectra with the recent BT-Settl model atmosphere. We derived metallicities based on the best fit of synthetic spectra to the observed spectra. Thanks to the high resolution of our spectra, we perform a detailed comparison of lines profile of individual elements such as Fe I, Ca II, Ti I, Na I, K I and are able to determine accurate metallicities of these stars which can be later linked to their kinematical properties. Our comparison shows that molecular features like TiO, VO and CaH, and atomic features like Fe I, Ti I, Na I, are very well reproduced by the model.

Rajpurohit, A. S.; Reyl, C.; Schultheis, M.; Allard, F.; Scholz, R.; Homeier, D.

86

Obtaining high resolution XUV coronal images  

NASA Technical Reports Server (NTRS)

Photographs obtained during three flights of an 11 inch diameter normal incident soft X-ray (wavelength 63.5 A) telescope are analyzed and the data are compared to the results expected from tests of the mirror surfaces. Multilayer coated X ray telescopes have the potential for 0.01 arcsec resolution, and there is optimism that such high quality mirrors can be built. Some of the factors which enter into the performance actually achieved in practice are as follows: quality of the mirror substrate, quality of the multilayer coating, and number of photons collected. Measurements of multilayer mirrors show that the actual performance achieved in the solar X-ray images demonstrates a reduction in the scattering compared to that calculated from the topography of the top surface of the multilayer. In the brief duration of a rocket flight, the resolution is also limited by counting statistics from the number of photons collected. At X-ray Ultraviolet (XUV) wavelengths from 171 to 335 A the photon flux should be greater than 10(exp 10) ph/sec, so that a resolution better than 0.1 arcsec might be achieved, if mirror quality does not provide a limit first. In a satellite, a large collecting area will be needed for the highest resolution.

Golub, L.; Spiller, E.

1992-01-01

87

Moderate resolution spectrophotometry of high redshift quasars  

NASA Technical Reports Server (NTRS)

A uniform set of photometry and high signal-to-noise moderate resolution spectroscopy of 33 quasars with redshifts larger than 3.1 is presented. The sample consists of 17 newly discovered quasars (two with redshifts in excess of 4.4) and 16 sources drawn from the literature. The objects in this sample have r magnitudes between 17.4 and 21.4; their luminosities range from -28.8 to -24.9. Three of the 33 objects are broad absorption line quasars. A number of possible high redshift damped Ly-alpha systems were found.

Schneider, Donald P.; Schmidt, Maarten; Gunn, James E.

1991-01-01

88

The High Resolution Array (HiRA).  

NASA Astrophysics Data System (ADS)

A new High Resolution Array (HiRA) is being constructed for experiments with rare isotope beams at the NSCL. It consists of twenty independent strip detector telescopes, which offer considerable flexibility in experimental setup. Each telescope is composed of two silicon strip detectors, 4 CsI(Tl) detectors and the necessary electronics, which includes a custom designed ASIC for the silicon strip detector readout. The thicknesses of the silicon detectors were selected to optimize the energy resolution for light particle detection over a wide range of particle energies. One of the silicon strip detectors is double-sided; the charge collected in orthogonal strips on opposite sides of this detector provide an x and y coordinate for each event in the telescope. The 1.9mm pitch in these detectors allows an approximate angular resolution of +/- .1 deg at a distance of 60cm. The silicon detectors are followed by 4 CsI(Th) scintillation detectors for detection of more energetic particles. High angular accuracy is needed for many proposed experiments with the array. This will be achieved with a semi-automated alignment procedure that utilizes a laser based optical triangulation sensor and precision stepper motor driven rotational stages.

Nett, B.; van Goethem; Lynch; Wallace; de Souza; Caraley; Davin; Viola; Alfaro-Molina; Hudan; Ryder; Yanez; Elson; Engel; Sobatka; Moroni

2002-10-01

89

The High Resolution Array HiRA  

NASA Astrophysics Data System (ADS)

A large solid angle, segmented, position sensitive, high-resolution array is being constructed for nuclear structure, astrophysics and reaction studies with radioactive ion beams. The array consists of 20 Silicon-Silicon-CsI(Tl) telescopes, each composed of a 65 um thick strip detector (DE1), a 1.5 mm thick silicon strip detector (DE2) and a 4 cm thick CsI(Tl) scintillator read out by a PIN diode (E). It will cover an laboratory angular range from 5 to 28 deg with angular resolution +- 0.16 deg. In this talk, details of the design and of the science that can be studied with the new array will be discussed. This work was supported by the National Science Foundation under Grant No. PHY-99-77707.

van Goethem, Marc-Jan; Caraley, A.; Charity, R. J.; Desouza, R. T.; Hosmer, P.; Lynch, William; Moroni, A.; Sobotka, L. G.; Verde, G.; Viola, V. E.; Wallace, M.

2000-10-01

90

Computer synthesis of high resolution electron micrographs  

NASA Technical Reports Server (NTRS)

Specimen damage, spherical aberration, low contrast and noisy sensors combine to prevent direct atomic viewing in a conventional electron microscope. The paper describes two methods for obtaining ultra-high resolution in biological specimens under the electron microscope. The first method assumes the physical limits of the electron objective lens and uses a series of dark field images of biological crystals to obtain direct information on the phases of the Fourier diffraction maxima; this information is used in an appropriate computer to synthesize a large aperture lens for a 1-A resolution. The second method assumes there is sufficient amplitude scatter from images recorded in focus which can be utilized with a sensitive densitometer and computer contrast stretching to yield fine structure image details. Cancer virus characterization is discussed as an illustrative example. Numerous photographs supplement the text.

Nathan, R.

1976-01-01

91

Applied high resolution digital control for universal precision systems  

E-print Network

This thesis describes the design and characterization of a high-resolution analog interface for dSPACE digital control systems and a high-resolution, high-speed data acquisition and control system. These designs are intended ...

Gawlik, Aaron John

2008-01-01

92

High resolution rainfall measurements around a high rise building  

Microsoft Academic Search

A number of disdrometers (acoustic rain gauge) has been placed around a high rise building on a place where variation in spatial distribution of precipitation is expected, to show the advantage of high resolution rainfall measurements in a urban area. The standard recommendation for the placement of a rain gauge is that the gauge is positioned at a distance corresponding

Stijn de Jong; Nick van de Giesen; Rolf Hut

2010-01-01

93

Operating mode of high pressure straws with high spatial resolution  

NASA Astrophysics Data System (ADS)

The article presents results of studying the operating mode of thin-walled drift tubes (straws) at flushing it with a high-pressure gas mixture, which allowed obtaining extremely high spatial resolution for straw detectors. The results of studying the radiation ageing of straws operating in this mode are also described.

Davkov, K. I.; Myalkovskiy, V. V.; Peshekhonov, V. D.; Cholakov, V. D.

2014-05-01

94

Effective Use of High-Resolution Models  

NSDL National Science Digital Library

High-resolution models have transitioned from research into forecast operations, helping forecasters utilize additional mesoscale information after accounting for the inherent unpredictability of many small-scale phenomena. This module covers the major capabilities and limitations of models run without a convective parameterization using grid spacings of around 4 km or less. Model forecast interpretation issues are discussed, including introducing convective mode diagnostics such as updraft helicity and interpreting the forecast as an event prediction rather than as a precise point forecast. Many examples are shown and twenty interactions engage the reader throughout the module.

Comet

2010-06-15

95

Detailed Mitochondrial Phenotyping by High Resolution Metabolomics  

PubMed Central

Mitochondrial phenotype is complex and difficult to define at the level of individual cell types. Newer metabolic profiling methods provide information on dozens of metabolic pathways from a relatively small sample. This pilot study used top-down metabolic profiling to determine the spectrum of metabolites present in liver mitochondria. High resolution mass spectral analyses and multivariate statistical tests provided global metabolic information about mitochondria and showed that liver mitochondria possess a significant phenotype based on gender and genotype. The data also show that mitochondria contain a large number of unidentified chemicals. PMID:22412977

Roede, James R.; Park, Youngja; Li, Shuzhao; Strobel, Frederick H.; Jones, Dean P.

2012-01-01

96

High Resolution Spectroscopy with Submillimeter-Wave  

NASA Astrophysics Data System (ADS)

In order to explain the characteristic features of planetary atmosphere, detection and precise measurements of environmentally important gases such as CO, CIO, No becomes necessary. Since most of the polyatomic molecules have (ro-vibrational) transitions in submillimeter region 100 ?-1000?), probing in this wavelength region is vital. The specific rotational and vibrational states are the result of interactions between different atoms in the molecule. Since each molecule has a unique arrangement of atoms, it has an exclusive submillimeter signature. We are developing a portable heterodyne receiver system at Physical Research Laboratory, Ahmedabad to perform high-resolution spectroscopy in this wavelength region.

Kumar, Vinay; Dave, Hemant

2003-03-01

97

Photoplethysmographic imaging of high spatial resolution  

PubMed Central

We present a new method of formation photoplethysmographic images with high spatial resolution from video recordings of a living body in the reflection geometry. The method (patent pending) is based on lock-in amplification of every pixel of the recorded video frames. A reference function required for synchronous detection of cardiovascular pulse waves is formed from the same frames. The method is featured by ability to visualize dynamic changes in cardiovascular pulse wave during the cardiac (or respiratory) cycle. We demonstrate that the system is capable to detect the minimal irritations of the body such as gentle scratching of the skin by own finger. PMID:21483621

Kamshilin, Alexei A.; Miridonov, Serguei; Teplov, Victor; Saarenheimo, Riku; Nippolainen, Ervin

2011-01-01

98

Photoplethysmographic imaging of high spatial resolution.  

PubMed

We present a new method of formation photoplethysmographic images with high spatial resolution from video recordings of a living body in the reflection geometry. The method (patent pending) is based on lock-in amplification of every pixel of the recorded video frames. A reference function required for synchronous detection of cardiovascular pulse waves is formed from the same frames. The method is featured by ability to visualize dynamic changes in cardiovascular pulse wave during the cardiac (or respiratory) cycle. We demonstrate that the system is capable to detect the minimal irritations of the body such as gentle scratching of the skin by own finger. PMID:21483621

Kamshilin, Alexei A; Miridonov, Serguei; Teplov, Victor; Saarenheimo, Riku; Nippolainen, Ervin

2011-01-01

99

New high resolution solar telescope GREGOR  

NASA Astrophysics Data System (ADS)

The 1.5m solar telescope GREGOR is being constructed at Tenerife, Spain. Its purpose is to observe with high spatial and spectral resolution small-scale dynamic magnetic features on the Sun. The telescope is completely open with retractable dome and actively cooled primary mirror made of silicon carbide to minimize thermal effects on the image quality. After completion it will be one of the most powerful solar telescopes. This paper presents a general overview of the telescope characteristics and the current status.

Volkmer, R.; von der Lhe, O.; Kneer, F.; Staude, J.; Balthasar, H.; Berkefeld, T.; Caligari, P.; Collados, M.; Halbgewachs, C.; Heidecke, F.; Hofmann, A.; Klvaa, M.; Sobotka, M.; Nicklas, H.; Popow, E.; Puschmann, K. G.; Schmidt, W.; Soltau, D.; Strassmeier, K.; Wittmann, A. D.

100

High resolution extremity CT for biomechanics modeling  

SciTech Connect

With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

1995-09-23

101

High resolution millimeter-wave imaging sensor  

NASA Technical Reports Server (NTRS)

A scanning 3-mm radiometer is described that has been built for use on a small aircraft to produce real time high resolution images of the ground when atmospheric conditions such as smoke, dust, and clouds make IR and visual sensors unusable. The sensor can be used for a variety of remote sensing applications such as measurements of snow cover and snow water equivalent, precipitation mapping, vegetation type and extent, surface moisture and temperature, and surface thermal inertia. The advantages of millimeter waves for cloud penetration and the ability to observe different physical phenomena make this system an attractive supplement to visible and IR remote sensing systems.

Wilson, W. J.; Howard, R. J.; Parks, G. S.

1985-01-01

102

High resolution detection system of capillary electrophoresis  

NASA Astrophysics Data System (ADS)

The capillary electrophoresis (CE) with laser induced fluorescence detection (LIFD) system was founded according to confocal theory. The 3-D adjustment of the exciting and collecting optical paths was realized. The photomultiplier tube (PMT) is used and the signals are processed by a software designed by ourselves. Under computer control, high voltage is applied to appropriate reservoirs and to inject and separate DNA samples respectively. Two fluorescent dyes Thiazole Orange (TO) and SYBR Green I were contrasted. With both of the dyes, high signals-to-noise images were obtained with the CE-LIFD system. The single-bases can be distinguished from the electrophoretogram and high resolution of DNA sample separation was obtained.

Wang, Jie; Wang, Li Qiang; Shi, Yan; Zheng, Hua; Lu, Zu Kang

2007-12-01

103

Efficient Compression of High Resolution Climate Data  

NASA Astrophysics Data System (ADS)

resolution climate data can be massive. Those data can consume a huge amount of disk space for storage, incur significant overhead for outputting data during simulation, introduce high latency for visualization and analysis, and may even make interactive visualization and analysis impossible given the limit of the data that a conventional cluster can handle. These problems can be alleviated by with effective and efficient data compression techniques. Even though HDF5 format supports compression, previous work has mainly focused on employ traditional general purpose compression schemes such as dictionary coder and block sorting based compression scheme. Those compression schemes mainly focus on encoding repeated byte sequences efficiently and are not well suitable for compressing climate data consist mainly of distinguished float point numbers. We plan to select and customize our compression schemes according to the characteristics of high-resolution climate data. One observation on high resolution climate data is that as the resolution become higher, values of various climate variables such as temperature and pressure, become closer in nearby cells. This provides excellent opportunities for predication-based compression schemes. We have performed a preliminary estimation of compression ratios of a very simple minded predication-based compression ratio in which we compute the difference between current float point number with previous float point number and then encoding the exponent and significance part of the float point number with entropy-based compression scheme. Our results show that we can achieve higher compression ratios between 2 and 3 in lossless compression, which is significantly higher than traditional compression algorithms. We have also developed lossy compression with our techniques. We can achive orders of magnitude data reduction while ensure error bounds. Moreover, our compression scheme is much more efficient and introduces much less overhead compared to traditaion compression algorithms. Our compression algorithms can also be parallelized easily. We have intergrated our compression algorithms to several simple climate analysis applications. We have carefully pipelined the applications so that the overhead introduced by compression does not undermine the advantage of reducing I/O overhead from compression. Our experimental results show that we improve end-to-end application performance as well as reduce storage requirements with compression.

Yin, J.; Schuchardt, K. L.

2011-12-01

104

Crusta: Visualizing High-resolution Global Data  

NASA Astrophysics Data System (ADS)

Virtual globes have become indispensable tools for visualizing, understanding and presenting data from Earth and other planetary bodies. The scientific community has invested much effort into exploiting existing globes to their fullest potential by refining and adapting their capabilities to better satisfy specific needs. For example, Google Earth provides users with the ability to view hillshade images derived from airborne LiDAR data such as the 2007 Northern California GeoEarthScope data. However, because most available globes were not designed with the specific needs of geoscientists in mind, shortcomings are becoming increasingly evident in geoscience applications such as terrain visualization. In particular, earth scientists struggle to visualize digital elevation models with both high spatial resolution (0.5 - 1 square meters per sample) and large extent (>2000 square kilometers), such as those obtained with airborne LiDAR. To address the specific earth science need of real-time terrain visualization of LiDAR data, we are developing Crusta as part of a close collaboration involving earth and computer scientists. Crusta is a new virtual globe that differs from widely used globes by both providing accurate global data representation and the ability to easily visualize custom topographic and image data. As a result, Crusta enables real-time, interactive visualization of high resolution digital elevation data spanning thousands of square kilometers, such as the complete 2007 Northern California GeoEarthScope airborne LiDAR data set. To implement an accurate data representation and avoid distortion of the display at the poles, where other projections have singularities, Crusta represents the globe as a thirty-sided polyhedron. Each side of this polyhedron can be subdivided to an arbitrarily fine grid on the surface of the globe, which allows Crusta to accommodate input data of arbitrary resolution ranging from global (e.g., Blue Marble) to local (e.g., a tripod LiDAR survey). Use of the GDAL library facilitates importing a number of data formats into the Crusta-specific, multi-scale hierarchies that enable interactive visualization on platforms ranging from laptops to immersive geowalls and caves. In addition to the underlying data representation, we also designed Crusta to be dynamic. The shading of the terrain surface is computed in real-time and on the fly when a user manipulates the viewpoint. Likewise, Crusta allows dynamic adjustment of the vertical exaggeration for the display of the globe's surface over an unlimited range of scales. The combination of these two effects greatly improves the perception of shape in high-resolution digital elevation data, critically enhancing the observation of minute details within the context of larger areas

Bernardin, T. S.; Kreylos, O.; Bowles, C. J.; Cowgill, E.; Hamann, B.; Kellogg, L. H.

2009-12-01

105

High Resolution Powder Diffraction and Structure Determination  

SciTech Connect

It is clear that high-resolution synchrotrons X-ray powder diffraction is a very powerful and convenient tool for material characterization and structure determination. Most investigations to date have been carried out under ambient conditions and have focused on structure solution and refinement. The application of high-resolution techniques to increasingly complex structures will certainly represent an important part of future studies, and it has been seen how ab initio solution of structures with perhaps 100 atoms in the asymmetric unit is within the realms of possibility. However, the ease with which temperature-dependence measurements can be made combined with improvements in the technology of position-sensitive detectors will undoubtedly stimulate precise in situ structural studies of phase transitions and related phenomena. One challenge in this area will be to develop high-resolution techniques for ultra-high pressure investigations in diamond anvil cells. This will require highly focused beams and very precise collimation in front of the cell down to dimensions of 50 {micro}m or less. Anomalous scattering offers many interesting possibilities as well. As a means of enhancing scattering contrast it has applications not only to the determination of cation distribution in mixed systems such as the superconducting oxides discussed in Section 9.5.3, but also to the location of specific cations in partially occupied sites, such as the extra-framework positions in zeolites, for example. Another possible application is to provide phasing information for ab initio structure solution. Finally, the precise determination of f as a function of energy through an absorption edge can provide useful information about cation oxidation states, particularly in conjunction with XANES data. In contrast to many experiments at a synchrotron facility, powder diffraction is a relatively simple and user-friendly technique, and most of the procedures and software for data analysis are familiar to laboratory diffractionists. This is reflected in the fact that there are already dedicated instruments for powder diffraction at a number of synchrotrons sources, including the NSLS, the Synchrotrons Radiation Source, Daresbury, the Photon Factory, Tsukuba and HASYLAB. In addition, most general purpose beamlines can be adapted for powder diffraction experiments fairly easily. Dedicated beamlines are also planned or under consideration at the next generation of synchrotrons sources, the European Synchrotron Radiation Facility, Grenoble, the Advanced Photon Source, Argonne, and the SPring-8 machine at Harima. These will be high brilliance sources with a much harder radiation spectrum that will offer many new possibilities for powder diffraction experiments, especially at energies above 10 keV.

Cox, D. E.

1999-04-23

106

High resolution multimodal clinical ophthalmic imaging system  

PubMed Central

We developed a multimodal adaptive optics (AO) retinal imager which is the first to combine high performance AO-corrected scanning laser ophthalmoscopy (SLO) and swept source Fourier domain optical coherence tomography (SSOCT) imaging modes in a single compact clinical prototype platform. Such systems are becoming ever more essential to vision research and are expected to prove their clinical value for diagnosis of retinal diseases, including glaucoma, diabetic retinopathy (DR), age-related macular degeneration (AMD), and retinitis pigmentosa. The SSOCT channel operates at a wavelength of 1 m for increased penetration and visualization of the choriocapillaris and choroid, sites of major disease activity for DR and wet AMD. This AO system is designed for use in clinical populations; a dual deformable mirror (DM) configuration allows simultaneous low- and high-order aberration correction over a large range of refractions and ocular media quality. The system also includes a wide field (33 deg.) line scanning ophthalmoscope (LSO) for initial screening, target identification, and global orientation, an integrated retinal tracker (RT) to stabilize the SLO, OCT, and LSO imaging fields in the presence of lateral eye motion, and a high-resolution LCD-based fixation target for presentation of visual cues. The system was tested in human subjects without retinal disease for performance optimization and validation. We were able to resolve and quantify cone photoreceptors across the macula to within ~0.5 deg (~100-150 m) of the fovea, image and delineate ten retinal layers, and penetrate to resolve features deep into the choroid. The prototype presented here is the first of a new class of powerful flexible imaging platforms that will provide clinicians and researchers with high-resolution, high performance adaptive optics imaging to help guide therapies, develop new drugs, and improve patient outcomes. PMID:20589021

Mujat, Mircea; Ferguson, R. Daniel; Patel, Ankit H.; Iftimia, Nicusor; Lue, Niyom; Hammer, Daniel X.

2010-01-01

107

Infrared spectroscopic imaging with high spatial resolution and high sensitivity  

NASA Astrophysics Data System (ADS)

Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) is a very sensitive imaging technique for the characterization of molecular films. In order to achieve a spatial resolution close to the diffraction limit a very small pinhole which acts as a point-source has to be used. However, such a small pinhole, the typical diameter would be app. 100 ?m, may reduces dramatically the intensity of the infrared beam. Using a common FTIR spectrometer the spatial resolution is mainly limited by the brilliance of the globar infrared source. Therefore, an improvement in lateral resolution requires a more brilliant light source. The free electron laser (FEL) is such a high brilliant infrared source. The combination of the FEL with the PM-IRRAS imaging system is a new approach to capture spectroscopic images with an excellent spatial resolution close to the diffraction limit. PM-IRRAS images of a self assembly monolayer of phosphonic acid molecules onto a microstructures gold / aluminum oxide surface where characterized. The spectroscopic image exhibits a spatial resolution of app. 5 ?m. An evaluation of characteristic absorbance bands of the phosphate group reveals that phosphonic acid molecules bound with a high degree of orientation but differently at the gold and aluminum oxide surfaces. However, the spectroscopic image reveals also several domains of disordering across the surface. Such domains have a dimension of only few micrometers and can be identified in a high resolved PM-IRRAS image.

Sablinskas, Valdas; Steiner, Gerald; Ceponkus, Justinas; Salzer, Reiner

2008-02-01

108

High-Resolution Scintimammography: A Pilot Study  

SciTech Connect

This study evaluated a novel high-resolution breast-specific gamma camera (HRBGC) for the detection of suggestive breast lesions. Methods: Fifty patients (with 58 breast lesions) for whom a scintimammogram was clinically indicated were prospectively evaluated with a general-purpose gamma camera and a novel HRBGC prototype. The results of conventional and high-resolution nuclear studies were prospectively classified as negative (normal or benign) or positive (suggestive or malignant) by 2 radiologists who were unaware of the mammographic and histologic results. All of the included lesions were confirmed by pathology. Results: There were 30 benign and 28 malignant lesions. The sensitivity for detection of breast cancer was 64.3% (18/28) with the conventional camera and 78.6% (22/28) with the HRBGC. The specificity with both systems was 93.3% (28/30). For the 18 nonpalpable lesions, sensitivity was 55.5% (10/18) and 72.2% (13/18) with the general-purpose camera and the HRBGC, respectively. For lesions 1 cm, 7 of 15 were detected with the general-purpose camera and 10 of 15 with the HRBGC. Four lesions (median size, 8.5 mm) were detected only with the HRBGC and were missed by the conventional camera. Conclusion: Evaluation of indeterminate breast lesions with an HRBGC results in improved sensitivity for the detection of cancer, with greater improvement shown for nonpalpable and 1-cm lesions.

Rachel F. Brem; Joelle M. Schoonjans; Douglas A. Kieper; Stan Majewski; Steven Goodman; Cahid Civelek

2002-07-01

109

Common high-resolution MMW scene generator  

NASA Astrophysics Data System (ADS)

The development of a modularized millimeter wave (MMW) target and background high resolution scene generator is reported. The scene generator's underlying algorithms are applicable to both digital and real-time hardware-in-the-loop (HWIL) simulations. The scene generator will be configurable for a variety of MMW and multi-mode sensors employing state of the art signal processing techniques. At present, digital simulations for MMW and multi-mode sensor development and testing are custom-designed by the seeker vendor and are verified, validated, and operated by both the vendor and government in simulation-based acquisition. A typical competition may involve several vendors, each requiring high resolution target and background models for proper exercise of seeker algorithms. There is a need and desire by both the government and sensor vendors to eliminate costly re-design and re-development of digital simulations. Additional efficiencies are realized by assuring commonality between digital and HWIL simulation MMW scene generators, eliminating duplication of verification and validation efforts.

Saylor, Annie V.; McPherson, Dwight A.; Satterfield, H. DeWayne; Sholes, William J.; Mobley, Scott B.

2001-08-01

110

High Resolution Spectroscopy of Rocket Triggered Lightning  

NASA Astrophysics Data System (ADS)

In the Summer of 2012, optical spectra of rocket triggered lightning return strokes were recorded at the International Center for Lightning Research and Testing in north-central Florida. The spectra were recorded with a Phantom v710 high speed CMOS camera running at 670 kfps (kiloframes per second) with a 1 microsecond exposure time and a Princeton ProEM high speed CCD camera running at over 1,000 kfps with a 0.5 microsecond exposure time. Three separate volume phase holographic grisms were used during the study and were sensitive in the spectral ranges of 3800-6200 Angstroms, 6400-6700 Angstroms, 7600-7900 Angstroms. The first had a spectral resolution of 5 Angstroms, allowing the separation of singly ionized nitrogen multiplets. These spectra were recorded 50m above the ground with 0.65 m vertical field of view. The second and third spectrometers were recorded with the Princeton ProEM camera and had a resolution of 0.5 Angstroms. These spectra were recorded 50m above ground with 0.06 m vertical field of view. The evolution of important lines in the spectral ranges such as singly ionized nitrogen lines (including spatially resolved 4630 Angstrom multiplet), H-alpha, and a resolved 7774 Angstrom Neutral oxygen triplet will all be presented. The opacity of the lightning channel as well as number density, temperature, and conductivity, will be discussed along with channel base current.

Walker, T. D.; Christian, H. J.

2012-12-01

111

High Resolution Spectroscopy to Support Atmospheric Measurements  

NASA Technical Reports Server (NTRS)

The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as carbon dioxide, water vapor, ozone, methane, and carbon monoxide, to name a few. Measurements were made using the NASA Langley Tunable Diode Laser Spectrometer System (TDL) and several Fourier Transform Spectrometer Systems (FTS) around the globe. The results from these studies made remarkable improvements in the line positions and intensities for several molecules, particularly ozone and carbon dioxide in the 2 to 17-micrometer spectral region. Measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced line shift coefficients for infrared transitions of ozone, methane, and water vapor were also performed. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon-and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields.

Benner, D. Chris; Venkataraman, Malathy Devi

2000-01-01

112

High Resolution Spectroscopy to Support Atmospheric Measurements  

NASA Technical Reports Server (NTRS)

The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as carbon dioxide, water vapor, ozone, methane, and carbon monoxide, to name a few. Measurements were made using the NASA Langley Tunable Diode Laser Spectrometer System (TDL) and several Fourier Transform Spectrometer Systems (FTS) around the globe. The results from these studies made remarkable improvements in the line positions and intensities for several molecules, particularly ozone and carbon dioxide in the 2 to 17-micrometer spectral region. Measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced line shift coefficients for infrared transitions of ozone, methane, and water vapor were also performed. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon- and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields.

Benner, D. Chris; Venkataraman, Malathy Devi

2000-01-01

113

High Resolution Spectroscopy to Support Atmospheric Measurements  

NASA Technical Reports Server (NTRS)

Spectroscopic parameters (such as line position, intensity, broadening and shifting coefficients and their temperature dependences, line mixing coefficients etc.) for various molecular species of atmospheric interest are determined. In order to achieve these results, infrared spectra of several molecular bands are obtained using high-resolution recording instruments such as tunable diode laser spectrometer and Fourier transform spectrometers. Using sophisticated analysis routines (Multispectrum nonlinear least squares technique) these high-resolution infrared spectra are processed to determine the various spectral line parameters that are cited above. Spectra were taken using the McMath-Pierce Fourier transform spectrometer (FTS) at the National Solar Observatory on Kitt Peak, Arizona as well as the Bruker FTS at the Pacific Northwest National Laboratory (PNNL) at Richland, Washington. Most of the spectra are acquired not only at room temperature, but also at several different cold temperatures. This procedure is necessary to study the variation of the spectral line parameters as a function of temperature in order to simulate the Earth's and other planetary atmospheric environments. Depending upon the strength or weakness of the various bands recorded and analyzed, the length(s) of the absorption cells in which the gas samples under study are kept varied from a few centimeters up to several meters and the sample temperatures varied from approximately +30 C to -63 C. Research on several infrared bands of various molecular species and their isotopomers are undertaken. Those studies are briefly described.

Venkataraman, Malathy Devi

2003-01-01

114

The High Resolution Fly's Eye Project  

NASA Astrophysics Data System (ADS)

The High Resolution Fly's Eye (HiRes) is under construction at Dugway, Utah. It measures the longitudinal development profiles of cosmic ray air showers by means of atmospheric scintillation light which is produced in proportion to the number of shower particles at each atmospheric depth. The new detector has greater sensitivity and higher resolution than the former Utah Fly's Eye because its mirrors collect 2.3 times as much light, the pixel solid angle has been reduced by 1/25, and signals will be measured with flash ADC electronics. A 14-mirror prototype has operated for 3 years, measuring air showers in coincidence with the CASA/MIA detector arrays and also with the Fly'e Eye II detector. HiRes is designed to measure extremely high energy cosmic ray air showers stereoscopically, and a set of such stereo events has been collected during the past year using a second prototype of 4 mirror units located at a distance of 12.6 km from the 14-mirror prototype. Laser pulses and vertical flashers have proved useful for evaluating the detector's performance and for studying the variability of atmospheric aerosol concentrations. The HiRes collaboration includes the University of Adelaide, Columbia University, the University of Illinois, and the University of Utah.

Sommers, Paul

1996-05-01

115

High-resolution noncontact atomic force microscopy.  

PubMed

Progress in nanoscience and nanotechnology requires tools that enable the imaging and manipulation of matter at the atomic and molecular scale. During the last two decades or so, scanning probe-based techniques have proven to be particularly versatile in this regard. Among the various probe-based approaches, atomic force microscopy (AFM) stands out in many ways, including the total number of citations and the breadth of possible applications, ranging from materials characterization to nanofabrication and biological studies. However, while nanometer scale operation in different environments became routine, atomic resolution imaging remained elusive for a long time. The reason for this initial deficiency was that contact with the sample blunts atomically sharp tips, which are mandatory for successful atomic resolution imaging. This problem was overcome in the mid-1990s with the introduction of noncontact atomic force microscopy (NC-AFM), which represents a version of AFM where the cantilever is oscillated close to the sample surface without actually 'touching' it. This allows the preservation of the atomic sharpness of the tip while interaction-induced changes in the cantilever's resonance frequency are used to quantify the tip-sample distance. Since then, progress has been steady and includes the development of commercial instruments as well as the addition of many new capabilities beyond imaging, such as the identification and manipulation of individual atoms. A series of annual international conferences, starting in Osaka in 1998, have contributed significantly to this outstanding performance. The program of the most recent conference from this series, held in Madrid on 15-19 September 2008, reflects the maturity of this field, with an increasing number of groups developing strong activities that involve novel approaches and applications covering areas well beyond the original vacuum-based imaging. In this special issue of Nanotechnology we present a selection of original papers authored by many of the leading groups in the field with the goal of providing a well-balanced overview on the state-of-the-art in this rapidly evolving field. These papers, many of which are based on notable presentations given during the Madrid conference, feature highlights such as (1) the development of sophisticated force spectroscopy procedures that are able to map the complete 3D tip-sample force field on different surfaces; (2) the considerable resolution improvement of Kelvin probe force microscopy (reaching, in some cases, the atomic scale), which is accompanied by a thorough, quantitative understanding of the contrast observed; (3) the perfecting of atomic resolution imaging on insulating substrates, which helps reshape our microscopic understanding of surface properties and chemical activity of these surfaces; (4) the description of instrumental and methodological developments that pave the way to the atomic-scale characterization of magnetic and electronic properties of nanostructures, and last but not least (5) the extension of dynamic imaging modes to high-resolution operation in liquids, ultimately achieving atomic resolution. The latter developments are already having a significant impact in the highly competitive field of biological imaging under physiological conditions. This special issue of Nanotechnology would not have been possible without the highly professional support from Nina Couzin, Amy Harvey, Alex Wotherspoon and the entire Nanotechnology team at IOP Publishing. We are thankful for their help in pushing this project forward. We also thank the authors who have contributed their excellent original articles to this issue, the referees whose comments have helped make the issue an accurate portrait of this rapidly moving field, and the entire NC-AFM community that continues to drive NC-AFM to new horizons. PMID:19531843

Prez, Rubn; Garca, Ricardo; Schwarz, Udo

2009-07-01

116

Ultra-high resolution computed tomography imaging  

DOEpatents

A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

Paulus, Michael J. (Knoxville, TN); Sari-Sarraf, Hamed (Knoxville, TN); Tobin, Jr., Kenneth William (Harriman, TN); Gleason, Shaun S. (Knoxville, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

2002-01-01

117

DISLOCATION IMAGES IN HIGH RESOLUTION SCANNING ELECTRON MICROSCOPY  

E-print Network

in the high resolution scanning electron microscope with conventional filament have been obtained The previous article presented arguments for deve- loping scanning electron. microscope techniques385 DISLOCATION IMAGES IN HIGH RESOLUTION SCANNING ELECTRON MICROSCOPY R. M. STERN Department

Paris-Sud XI, Université de

118

Trade-offs between Angular and Spatial Resolution in High Angular Resolution Diffusion Imaging  

E-print Network

Trade-offs between Angular and Spatial Resolution in High Angular Resolution Diffusion Imaging? HARDI is one of Q-space imaging techniques for resolving complex fiber geometries. Where fibers cross linearly registered to a high-resolution single subject template, the Colin27, using 9-parameter

Thompson, Paul

119

High-resolution modelling of meteoroid ablation  

NASA Astrophysics Data System (ADS)

Context. The structure and composition of meteoroids is of great interest because of the insight it provides into their parent asteroids and comets. Aims: Recently acquired, high-resolution video measurements of meteors will be used to evaluate two models of meteoroid ablation. Methods: Ten meteors were observed with the Canadian Automated Meteor Observatory (CAMO), which uses pairs of mirrors to track meteors telescopically in the sky with a resolution of up to 3 meters per pixel. Two meteoroid ablation models were used to fit the wide-field light curves and deceleration measurements of the meteors, and the wakes predicted by each model were compared to the wakes measured in the telescopic system. Results: Both models produced satisfactory fits to the wide field measurements, but both were very poor at predicting the narrow field brightness profiles of the meteors. Conclusions: Models of meteoroid fragmentation in the atmosphere need significant improvement to match observations. Data from the CAMO observatory mirror systems provide significant constraints and can be used in the development of a new model of meteoroid ablation.

Campbell-Brown, M. D.; Borovi?ka, J.; Brown, P. G.; Stokan, E.

2013-09-01

120

High Resolution Laser Spectroscopy of Rhodium Monobromide.  

NASA Astrophysics Data System (ADS)

The rhodium monobromide molecule, RhBr, has been created in our laser ablation pulsed jet apparatus by ablating a rhodium target rod in the presence of 1% CH_3Br seeded in He. A low-resolution survey spectrum from 415 to 850 nm indicated the presence of a number of bands belonging to RhBr. Thirteen of these band systems, mainly in the blue spectral region, have been recorded at high resolution with our cw dye laser. In addition, dispersed fluorescence spectra have been obtained for these bands. Not all of the bands have been fully analyzed to date, however, from those analyzed, the RhBr ground state has been determined to have ?=2 consistent with the isovalent RhCl molecule which has a ^3?_2 ground state. Vibrational and rotational analysis yields the following ground state parameters for the two isotopologues, Rh79Br and Rh81Br: ?''=260 Cm-1, B''(Rh79Br)=0.0655 Cm-1, and B''(Rh81Br)=0.0646 Cm-1. Further ground and excited state parameters will be presented at the conference. S. A. Shepard, A. G. Adam, R. Li, and W. J. Balfour J. Mol. Spectrosc. 234, 99-105 (2005)

Adam, A. G.; Allen, T. F.; Downie, L. E.; Granger, A. D.; Linton, C.; Tokaryk, D. W.

2011-06-01

121

Clementine High Resolution Camera Mosaicking Project  

NASA Technical Reports Server (NTRS)

This report constitutes the final report for NASA Contract NASW-5054. This project processed Clementine I high resolution images of the Moon, mosaicked these images together, and created a 22-disk set of compact disk read-only memory (CD-ROM) volumes. The mosaics were produced through semi-automated registration and calibration of the high resolution (HiRes) camera's data against the geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic produced by the US Geological Survey (USGS). The HiRes mosaics were compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution nadir-looking observations. The images were spatially warped using the sinusoidal equal-area projection at a scale of 20 m/pixel for sub-polar mosaics (below 80 deg. latitude) and using the stereographic projection at a scale of 30 m/pixel for polar mosaics. Only images with emission angles less than approximately 50 were used. Images from non-mapping cross-track slews, which tended to have large SPICE errors, were generally omitted. The locations of the resulting image population were found to be offset from the UV/Vis basemap by up to 13 km (0.4 deg.). Geometric control was taken from the 100 m/pixel global and 150 m/pixel polar USGS Clementine Basemap Mosaics compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Radiometric calibration was achieved by removing the image nonuniformity dominated by the HiRes system's light intensifier. Also provided are offset and scale factors, achieved by a fit of the HiRes data to the corresponding photometrically calibrated UV/Vis basemap, that approximately transform the 8-bit HiRes data to photometric units. The sub-polar mosaics are divided into tiles that cover approximately 1.75 deg. of latitude and span the longitude range of the mosaicked frames. Images from a given orbit are map projected using the orbit's nominal central latitude. Polar mosaics are tiled into squares 2250 pixels on a side, which spans approximately 2.2 deg. Two mosaics are provided for each pole: one corresponding to data acquired while periapsis was in the south, the other while periapsis was in the north. The CD-ROMs also contain ancillary data files that support the HiRes mosaic. These files include browse images with UV/Vis context stored in a Joint Photographic Experts Group (JPEG) format, index files ('imgindx.tab' and 'srcindx.tab') that tabulate the contents of the CD, and documentation files.

1998-01-01

122

Genetic Analysis of High Angular Resolution Diffusion Images (HARDI)  

E-print Network

Genetic Analysis of High Angular Resolution Diffusion Images (HARDI) Liang Zhan1 , Alex D. Leow2 adult twins (29 identical and 29 fraternal twin pairs) with high-angular resolution diffusion imaging of variations in fiber integrity and connectivity in large human populations. Keywords: High-Angular Resolution

Thompson, Paul

123

High Resolution Infrared Spectroscopy in Astronomy  

Microsoft Academic Search

Infrared Spectroscopy at a resolution of a few km\\/s allows to study rotational-vibrational transitions of many abundant molecules as well as important atomic lines in a multitude of interesting astrophysical environments. The ESO VLT will shortly be equipped with two unique infrared spectrometers which combine spectral resolution with spatial resolutions of = 0.2 arcsec:

H. U. Kufl; A. Moorwood

2003-01-01

124

High resolution analysis of satellite gradiometry  

NASA Technical Reports Server (NTRS)

Satellite gravity gradiometry is a technique now under development which, by the middle of the next decade, may be used for the high resolution charting from space of the gravity field of the earth and, afterwards, of other planets. Some data analysis schemes are reviewed for getting detailed gravity maps from gradiometry on both a global and a local basis. It also presents estimates of the likely accuracies of such maps, in terms of normalized spherical harmonics expansions, both using gradiometry alone and in combination with data from a Global Positioning System (GPS) receiver carried on the same spacecraft. It compares these accuracies with those of current and future maps obtained from other data (conventional tracking, satellite-satellite tracking, etc.), and also with the spectra of various signals of geophysical interest.

Colombo, O. L.

1989-01-01

125

High resolution color band pyrometer ratioing  

NASA Technical Reports Server (NTRS)

The sensing head of a two-color band ratioing pyrometer of a known type using a fiber optic cable to couple radiation to dual detector photodiodes is improved to have high spatial resolution by focusing the radiation received through an objective lens (i.e., by focusing the image of a target area) onto an opaque sheet spaced in front of the input end of the fiber optic cable. A two-mil hole in that sheet then passes radiation to the input end of the cable. The detector has two channels, one for each color band, with an electronic-chopper stabilized current amplifier as the input stage followed by an electronic-chopper stabilized voltage amplifier.

Bickler, Donald B. (Inventor); Henry, Paul K. (Inventor); LoGiurato, D. Daniel (Inventor)

1989-01-01

126

Absolute, high-resolution optical position encoder  

NASA Astrophysics Data System (ADS)

Modern computer-controlled manufacturing machinery requires the absolute and highly accurate measurement of the linear position. Such an absolute, optical linear position encoder is described here. It is based on the transilluminance of a glass scale with an inexpensive light-emitting diode. The scale has two code tracks, one based on a pseudo-random binary sequence for the coarse determination of position and another periodic code for accurate fine-position measurement. A single-lens telecentric optical system images the code tracks in a mechanically insensitive way onto a custom photodetector. This special detector IC is capable of determining the components of the (complex) Fourier transform for the spatial frequency of the periodic code. The absolute optical position encoder shows a resolution of 10 nm andan absolute accuracy of better than 100 nm over short distances, verified with a commercial laser interferometer.

Engelhardt, Kai; Seitz, Peter

1996-01-01

127

Absolute, high-resolution optical position encoder.  

PubMed

Modern computer-controlled manufacturing machinery requires the absolute and highly accurate measurement of the linear position. Such an absolute, optical linear position encoder is described here. It is based on the transilluminance of a glass scale with an inexpensive light-emitting diode. The scale has two code tracks, one based on a pseudo-random binary sequence for the coarse determination of position and another periodic code for accurate fine-position measurement. A single-lens telecentric optical system images the code tracks in a mechanically insensitive way onto a custom photodetector. This special detector IC is capable of determining the components of the (complex) Fourier transform for the spatial frequency of the periodic code. The absolute optical position encoder shows a resolution of 10 nm and an absolute accuracy of better than 100 nm over short distances, verified with a commercial laser interferometer. PMID:21069000

Engelhardt, K; Seitz, P

1996-01-01

128

Potential High Resolution Dosimeters For MRT  

NASA Astrophysics Data System (ADS)

Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow (25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 ?m microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy/s, micron resolution and a dose range over several orders of magnitude. This paper will give an overview of all dosimeters tested in the past at the ESRF with their advantages and drawbacks. These detectors comprise: Ionization chambers, Alanine Dosimeters, MOSFET detectors, Gafchromic films, Radiochromic polymers, TLDs, Polymer gels, Fluorescent Nuclear Track Detectors (Al2O3:C, Mg single crystal detectors), OSL detectors and Floating Gate-based dosimetry system. The aim of such a comparison shall help with a decision on which of these approaches is most suitable for high resolution dose measurements in MRT. The principle of these detectors will be presented including a comparison for some dosimeters exposed with the same irradiation geometry, namely a 11 cm5 field size with microbeam exposures at the surface, 0.1 cm and 1 cm in depth of a PMMA phantom. For these test exposures, the most relevant irradiation parameters for future clinical trials have been chosen: 50 micron FWHM and 400 micron c-t-c distance. The experimental data are compared with Monte Carlo calculations.

Bruer-Krisch, E.; Rosenfeld, A.; Lerch, M.; Petasecca, M.; Akselrod, M.; Sykora, J.; Bartz, J.; Ptaszkiewicz, M.; Olko, P.; Berg, A.; Wieland, M.; Doran, S.; Brochard, T.; Kamlowski, A.; Cellere, G.; Paccagnella, A.; Siegbahn, E. A.; Prezado, Y.; Martinez-Rovira, I.; Bravin, A.; Dusseau, L.; Berkvens, P.

2010-07-01

129

Potential High Resolution Dosimeters For MRT  

SciTech Connect

Microbeam Radiation Therapy (MRT) uses highly collimated, quasi-parallel arrays of X-ray microbeams of 50-600 keV, produced by 2nd and 3rd generation synchrotron sources, such as the National Synchrotron Light Source (NSLS) in the U.S., and the European Synchrotron Radiation Facility (ESRF) in France, respectively. High dose rates are necessary to deliver therapeutic doses in microscopic volumes, to avoid spreading of the microbeams by cardiosynchronous movement of the tissues. A small beam divergence and a filtered white beam spectrum in the energy range between 30 and 250 keV results in the advantage of steep dose gradients with a sharper penumbra than that produced in conventional radiotherapy. MRT research over the past 20 years has allowed a vast number of results from preclinical trials on different animal models, including mice, rats, piglets and rabbits. Microbeams in the range between 10 and 100 micron width show an unprecedented sparing of normal radiosensitive tissues as well as preferential damage to malignant tumor tissues. Typically, MRT uses arrays of narrow ({approx}25-100 micron-wide) microplanar beams separated by wider (100-400 microns centre-to-centre, c-t-c) microplanar spaces. We note that thicker microbeams of 0.1-0.68 mm used by investigators at the NSLS are still called microbeams, although some invesigators in the community prefer to call them minibeams. This report, however, limits it discussion to 25-100 {mu}m microbeams. Peak entrance doses of several hundreds of Gy are surprisingly well tolerated by normal tissues. High resolution dosimetry has been developed over the last two decades, but typical dose ranges are adapted to dose delivery in conventional Radiation Therapy (RT). Spatial resolution in the sub-millimetric range has been achieved, which is currently required for quality assurance measurements in Gamma-knife RT. Most typical commercially available detectors are not suitable for MRT applications at a dose rate of 16000 Gy/s, micron resolution and a dose range over several orders of magnitude. This paper will give an overview of all dosimeters tested in the past at the ESRF with their advantages and drawbacks. These detectors comprise: Ionization chambers, Alanine Dosimeters, MOSFET detectors, Gafchromic registered films, Radiochromic polymers, TLDs, Polymer gels, Fluorescent Nuclear Track Detectors (Al{sub 2}O{sub 3}:C, Mg single crystal detectors), OSL detectors and Floating Gate-based dosimetry system. The aim of such a comparison shall help with a decision on which of these approaches is most suitable for high resolution dose measurements in MRT. The principle of these detectors will be presented including a comparison for some dosimeters exposed with the same irradiation geometry, namely a 1x1 cm{sup 5} field size with microbeam exposures at the surface, 0.1 cm and 1 cm in depth of a PMMA phantom. For these test exposures, the most relevant irradiation parameters for future clinical trials have been chosen: 50 micron FWHM and 400 micron c-t-c distance. The experimental data are compared with Monte Carlo calculations.

Braeuer-Krisch, E.; Brochard, T.; Prezado, Y.; Bravin, A.; Berkvens, P. [European Synchrotron Radiation Facility (ESRF), 6 rue Horowitz, BP220, F-38043 Grenoble (France); Rosenfeld, A.; Lerch, M.; Petasecca, M. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522 (Australia); Akselrod, M.; Sykora, J.; Bartz, J. [Landauer, Inc., Stillwater Crystal Growth Division, Stillwater OK, 74074 (United States); Ptaszkiewicz, M.; Olko, P. [Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Department of Radiation Physics and Dosimetry, ul. Radzikowskiego 152, PL 31-342 Krakow (Poland); Berg, A.; Wieland, M. [Medizinische Universitaet Wien, Zentrum f. Biomedizinische Technik und Physik (Austria); Doran, S. [Department of Physics, University of Surrey, Guildford (United Kingdom); Kamlowski, A. [Bruker Biospin, Rheinstetten (Germany); Cellere, G. [DEI, Department of Information Engineering, via Gradenigo, 6/B, 35131 PADOVA (Italy) and Applied Materials Baccini Via Postumia Ovest, 244, 31050 San Biagio di Callalta, Treviso; Paccagnella, A. [DEI, Department of Information Engineering, via Gradenigo, 6/B, 35131 PADOVA (Italy); Siegbahn, E. A. [Department of Medical Physics, Karolinska Universitetssjukhuset, 17176 Stockholm (Sweden)

2010-07-23

130

Improved methods for high resolution electron microscopy  

SciTech Connect

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.

Taylor, J.R.

1987-04-01

131

Minimally invasive diagnostic imaging using high resolution Optical Coherence Tomography  

E-print Network

Advances in medical imaging have given researchers unprecedented capabilities to visualize, characterize and understand biological systems. Optical Coherence Tomography (OCT) is a high speed, high resolution imaging technique ...

Herz, Paul Richard, 1972-

2004-01-01

132

High Resolution Airborne Shallow Water Mapping  

NASA Astrophysics Data System (ADS)

In order to meet the requirements of the European Water Framework Directive (EU-WFD), authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim) a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length) of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river bed was achieved throughout the project. During the data processing meshes for multiple purposes like monitoring sediment transport or accumulation and hydro-dynamic numeric modeling were generated. The meshes were professionally conditioned considering the adherence of, both, geometric and physical mesh quality criterions. Whereas the research is focused on the design and implementation of monitoring database structures, the airborne hydrographic data are also made available for classical processing means (cross sections, longitudinal section).

Steinbacher, F.; Pfennigbauer, M.; Aufleger, M.; Ullrich, A.

2012-07-01

133

A low noise, high resolution silicon temperature sensor  

Microsoft Academic Search

High resolution temperature measurement is essential for determination of blood perfusion in biomaterials. A compact, low noise, high resolution temperature sensor designed for use in an invasive tissue property measurement probe is presented. The circuit is based on traditional proportional-to-absolute-temperature (PTAT) principles. A feedback technique is used to improve linearity and reduce noise. Data from test chips shows temperature resolution

Kenneth S. Szajda; Charles G. Sodini; H. Frederick Bowman

1996-01-01

134

18F-FDG positron autoradiography with a particle counting silicon pixel detector.  

PubMed

We report on tests of a room-temperature particle counting silicon pixel detector of the Medipix2 series as the detector unit of a positron autoradiography (AR) system, for samples labelled with (18)F-FDG radiopharmaceutical used in PET studies. The silicon detector (1.98 cm(2) sensitive area, 300 microm thick) has high intrinsic resolution (55 microm pitch) and works by counting all hits in a pixel above a certain energy threshold. The present work extends the detector characterization with (18)F-FDG of a previous paper. We analysed the system's linearity, dynamic range, sensitivity, background count rate, noise, and its imaging performance on biological samples. Tests have been performed in the laboratory with (18)F-FDG drops (37-37 000 Bq initial activity) and ex vivo in a rat injected with 88.8 MBq of (18)F-FDG. Particles interacting in the detector volume produced a hit in a cluster of pixels whose mean size was 4.3 pixels/event at 11 keV threshold and 2.2 pixels/event at 37 keV threshold. Results show a sensitivity for beta(+) of 0.377 cps Bq(-1), a dynamic range of at least five orders of magnitude and a lower detection limit of 0.0015 Bq mm(-2). Real-time (18)F-FDG positron AR images have been obtained in 500-1000 s exposure time of thin (10-20 microm) slices of a rat brain and compared with 20 h film autoradiography of adjacent slices. The analysis of the image contrast and signal-to-noise ratio in a rat brain slice indicated that Poisson noise-limited imaging can be approached in short (e.g. 100 s) exposures, with approximately 100 Bq slice activity, and that the silicon pixel detector produced a higher image quality than film-based AR. PMID:18923198

Russo, P; Lauria, A; Mettivier, G; Montesi, M C; Marotta, M; Aloj, L; Lastoria, S

2008-11-01

135

18F-FDG positron autoradiography with a particle counting silicon pixel detector  

NASA Astrophysics Data System (ADS)

We report on tests of a room-temperature particle counting silicon pixel detector of the Medipix2 series as the detector unit of a positron autoradiography (AR) system, for samples labelled with 18F-FDG radiopharmaceutical used in PET studies. The silicon detector (1.98 cm2 sensitive area, 300 m thick) has high intrinsic resolution (55 m pitch) and works by counting all hits in a pixel above a certain energy threshold. The present work extends the detector characterization with 18F-FDG of a previous paper. We analysed the system's linearity, dynamic range, sensitivity, background count rate, noise, and its imaging performance on biological samples. Tests have been performed in the laboratory with 18F-FDG drops (37-37 000 Bq initial activity) and ex vivo in a rat injected with 88.8 MBq of 18F-FDG. Particles interacting in the detector volume produced a hit in a cluster of pixels whose mean size was 4.3 pixels/event at 11 keV threshold and 2.2 pixels/event at 37 keV threshold. Results show a sensitivity for ?+ of 0.377 cps Bq-1, a dynamic range of at least five orders of magnitude and a lower detection limit of 0.0015 Bq mm-2. Real-time 18F-FDG positron AR images have been obtained in 500-1000 s exposure time of thin (10-20 m) slices of a rat brain and compared with 20 h film autoradiography of adjacent slices. The analysis of the image contrast and signal-to-noise ratio in a rat brain slice indicated that Poisson noise-limited imaging can be approached in short (e.g. 100 s) exposures, with ~100 Bq slice activity, and that the silicon pixel detector produced a higher image quality than film-based AR.

Russo, P.; Lauria, A.; Mettivier, G.; Montesi, M. C.; Marotta, M.; Aloj, L.; Lastoria, S.

2008-11-01

136

Stapes model using high-resolution ?CT  

NASA Astrophysics Data System (ADS)

Understanding the biomechanics of the middle ear is important for surgical reconstructions. As the output of the middle ear, the stapes plays a key role in transferring acoustic vibrations to the cochlea. In order to develop anatomically-based mathematical models, which are needed to improve our understanding of stapes dynamics, detailed morphometry of the stapes is required. High-resolution micro-CT imaging techniques were used to generate three-dimensional reconstructions of cadaveric temporal bones from 5 species commonly used in experimental middle ear research: the chinchilla, human (relatively mid-frequency hearing limit), cat, guinea pig, and gerbil (relatively high-frequency hearing limit). From the standard discretizations of micro-CT images and corresponding 3-D volume reconstructions, the centers of mass, principle axes, stapes head areas and stapes footplate areas were calculated. Mechanical relationships were estimated between the capitulum area and the footplate area and inter-species comparisons were performed between the cross-sectional shapes of the anterior and posterior crura. Quantitative dynamic properties were estimated from the rigid body motion calculations. The parameters estimated in this study will be useful for building biocomputational models of the stapes for a variety of species.

Baek, Jong Dae; Puria, Sunil

2008-02-01

137

Feasibility study of an avalanche photodiode readout for a high resolution PET with nsec time resolution  

Microsoft Academic Search

A feasibility study for a high resolution positron emission tomograph, based on 9.544 mm3 LSO crystals viewed by 3 mm diameter avalanche photodiodes, has been carried out. Using a Na22 source we determined a spatial resolution of 2.30.1 mm, an energy resolution around 15 % and a time resolution of 2.6 nsec. Possible configurations for larger scale tests and a

C. Schmelz; S. M. Bradbury; I. Holl; E. Lorenz; D. Renker; S. Ziegler

1995-01-01

138

High-resolution optical fiber reflectometry techniques  

Microsoft Academic Search

This paper reviews optical reflectometry techniques that are capable of achieving spatial resolutions of less than 1 cm. Advantages and disadvantages of these techniques are discussed. A white light interferometry technique known as optical low-coherence reflectometry is emphasized. This technique has been used to obtain spatial resolutions on the order of tens of microns and reflection sensitivities as low as

Wayne V. Sorin

1993-01-01

139

High-resolution colorimetric imaging of paintings  

Microsoft Academic Search

With the aim of providing a digital electronic replacement for conventional photography of paintings, a scanner has been constructed based on a 3000 X 2300 pel resolution camera which is moved precisely over a 1 meter square area. Successive patches are assembled to form a mosaic which covers the whole area at c. 20 pels\\/mm resolution, which is sufficient to

Kirk Martinez; John Cupitt; David R. Saunders

1993-01-01

140

Single sensor processing to obtain high resolution color component signals  

NASA Technical Reports Server (NTRS)

A method for generating color video signals representative of color images of a scene includes the following steps: focusing light from the scene on an electronic image sensor via a filter having a tri-color filter pattern; producing, from outputs of the sensor, first and second relatively low resolution luminance signals; producing, from outputs of the sensor, a relatively high resolution luminance signal; producing, from a ratio of the relatively high resolution luminance signal to the first relatively low resolution luminance signal, a high band luminance component signal; producing, from outputs of the sensor, relatively low resolution color component signals; and combining each of the relatively low resolution color component signals with the high band luminance component signal to obtain relatively high resolution color component signals.

Glenn, William E. (Inventor)

2010-01-01

141

The High Resolution Tropospheric Ozone Residual  

NASA Technical Reports Server (NTRS)

The co-flight of the MLS stratospheric limb sounder and the Ozone Monitoring Instrument (OMI) provides the capability of computing the Tropospheric Ozone Residual (TOR) in much greater detail [Ziemke et al., 2006]. Using forward trajectory calculations of MLS ozone measurements combined with OMI column ozone we have developed a high horizontal resolution tropospheric ozone residual (HTOR) which can provide even more detail than the standard TOR product. HTOR is especially useful for extra-tropical studies of tropospheric ozone transport. We find that both the Pacific pollution corridor (East Asia to Alaska) and the Atlantic pollution corridor (North America east coast to Europe) are also preferred locations for strat-trop folds leading to systematic overestimates of pollution amounts. In fact, fold events appear to dominate extra-tropical Northern Hemisphere day-to-day maps of HTOR. Model estimates of the tropospheric column are in reasonable agreement with the HTOR amounts when offsets due to different tropopause height calculations are taken into consideration.

Schoeberl, Mark R.

2006-01-01

142

The High Resolution Array (HiRA)  

NASA Astrophysics Data System (ADS)

A High Resolution Array consisting of 20 strip detectors telescopes is being constructed by a collaboration consisting of scientists at Michigan State University, Indiana University, Washington University, Southern Illinois University and INFN Milano. Each telescope in the array contains two silicon strip detectors backed by 4 CsI(Tl) crystals. The front silicon is 65 microns thick and is segmented into 32 strips with a 1.9 mm pitch. The second silicon is 1.5 mm thick and is segmented into 32 strips on the front and the back sides. The strips on the front and back are perpendicular allowing each telescope to be segmented into 1024 pixels. The 4 CsI(Tl) crystals in each telescope are 4 cm thick; each backs one quarter of the solid angle of the telescope. To reduce the cost of electronic readout, an ASIC is being developed that contains the pre-amplifiers, shapers, discriminators, TAC's, and sample and hold circuits required to read out 32 silicon strip channels. The chip has a large dynamic range (10-100 MeV), and multiple readout modes. The different elements of the detector will be discussed in detail. Work supported by the NSF, grant NSF-PHY-01-10253

Wallace, M. S.; van Goethem, M. J.; Nett, B. E.; Oostdyk, D.; Lynch, W. G.; Tsang, M. B.; de Souza, Rt.; Caraley, A. L.; Davin, B. P.; Sobotka, L. G.; Charity, Rj; Elson, J.; Engel, G.; Moroni, A.

2002-10-01

143

High resolution scanning electron microscopy of plasmodesmata.  

PubMed

Symplastic transport occurs between neighbouring plant cells through functionally and structurally dynamic channels called plasmodesmata (PD). Relatively little is known about the composition of PD or the mechanisms that facilitate molecular transport into neighbouring cells. While transmission electron microscopy (TEM) provides 2-dimensional information about the structural components of PD, 3-dimensional information is difficult to extract from ultrathin sections. This study has exploited high-resolution scanning electron microscopy (HRSEM) to reveal the 3-dimensional morphology of PD in the cell walls of algae, ferns and higher plants. Varied patterns of PD were observed in the walls, ranging from uniformly distributed individual PD to discrete clusters. Occasionally the thick walls of the giant alga Chara were fractured, revealing the surface morphology of PD within. External structures such as spokes, spirals and mesh were observed surrounding the PD. Enzymatic digestions of cell wall components indicate that cellulose or pectin either compose or stabilise the extracellular spokes. Occasionally, the PD were fractured open and desmotubule-like structures and other particles were observed in their central regions. Our observations add weight to the argument that Chara PD contain desmotubules and are morphologically similar to higher plant PD. PMID:21626150

Brecknock, Sarah; Dibbayawan, Teresa P; Vesk, Maret; Vesk, Peter A; Faulkner, Christine; Barton, Deborah A; Overall, Robyn L

2011-10-01

144

High resolution EUV monochromator/spectrometer  

DOEpatents

This invention is related to a monochromator which employs a spherical mirror, a traveling plane mirror with simultaneous rotation, and a varied spacing plane grating. The divergent beam from the entrance slit is converged by the spherical mirror located at the various positions in the monochromator depending of the inventive system. To provide the meaningful diffraction efficiencies and to reduce unwanted higher order lights, the deviation angle subtending the incidence and diffraction beams for the plane grating is varied with the position of the traveling plane mirror with simultaneous rotation located in the front or back of the plane grating with wavelength scanning. The outgoing beam from the monochromator goes through the fixed exit slit and has same beam direction regardless of the scanning wavelength. The combination of properly designed motions of the plane mirror and novel varied-spacing parameters of the inventive plane grating corrects the aberrations and focuses the monochromatic spectral image on the exit slit, enabling measurements at high spectral resolution. 10 figs.

Koike, Masako

1996-06-18

145

High resolution EUV monochromator/spectrometer  

DOEpatents

This invention is related to a monochromator which employs a spherical mirror, a traveling plane mirror with simultaneous rotation, and a varied spacing plane grating. The divergent beam from the entrance slit is converged by the spherical mirror located at the various positions in the monochromator depending of the inventive system. To provide the meaningful diffraction efficiencies and to reduce unwanted higher order lights, the deviation angle subtending the incidence and diffraction beams for the plane grating is varied with the position of the traveling plane mirror with simultaneous rotation located in the front or back of the plane grating with wavelength scanning. The outgoing beam from the monochromator goes through the fixed exit slit and has same beam direction regardless of the scanning wavelength. The combination of properly designed motions of the plane mirror and novel varied-spacing parameters of the inventive plane grating corrects the aberrations and focuses the monochromatic spectral image on the exit slit, enabling measurements at high spectral resolution.

Koike, Masako (Moraga, CA)

1996-01-01

146

Intracellular membrane traffic at high resolution  

PubMed Central

I. Abstract Membrane traffic between organelles is essential for a multitude of processes that maintain cell homeostasis. Many steps in these tightly regulated trafficking pathways take place in microdomains on the membranes of organelles, which require analysis at nanometer resolution. Electron Microscopy (EM) can visualize these processes in detail and is mainly responsible for our current view of morphology on the subcellular level. This review discusses how EM can be applied to solve many questions of intracellular membrane traffic, with a focus on the endosomal system. We describe the expansion of the technique from purely morphological analysis to cryo-immuno-EM, Correlative Light Electron Microscopy (CLEM) and 3D electron tomography. In this review we go into some technical details of these various techniques. Furthermore, we provide a full protocol for immunolabeling on Lowicryl sections of high-pressure frozen cells as well as a detailed description of a simple CLEM method that can be applied to answer many membrane trafficking questions. We believe that these EM-based techniques are important tools to expand our understanding of the molecular details of endosomal sorting and intracellular membrane traffic in general. PMID:20869541

van Weering, Jan R.T.; Brown, Edward; Sharp, Thomas H.; Mantell, Judith; Cullen, Peter J.

2014-01-01

147

High-resolution imaging using endoscopic holography  

NASA Astrophysics Data System (ADS)

Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help to their control. 1.

Bjelkhagen, Hans I.

1990-08-01

148

Holographic high-resolution endoscopic image recording  

NASA Astrophysics Data System (ADS)

Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help

Bjelkhagen, Hans I.

1991-03-01

149

High vertical resolution crosswell seismic imaging  

DOEpatents

A method for producing high vertical resolution seismic images from crosswell data is disclosed. In accordance with one aspect of the disclosure, a set of vertically spaced, generally horizontally extending continuous layers and associated nodes are defined within a region between two boreholes. The specific number of nodes is selected such that the value of a particular characteristic of the subterranean region at each of the nodes is one which can be determined from the seismic data. Once values are established at the nodes, values of the particular characteristic are assigned to positions between the node points of each layer based on the values at node within that layer and without regard to the values at node points within any other layer. A seismic map is produced using the node values and the assigned values therebetween. In accordance with another aspect of the disclosure, an approximate model of the region is established using direct arrival traveltime data. Thereafter, the approximate model is adjusted using reflected arrival data. In accordance with still another aspect of the disclosure, correction is provided for well deviation. An associated technique which provides improvements in ray tracing is also disclosed.

Lazaratos, Spyridon K. (Houston, TX)

1999-12-07

150

High-resolution ophthalmic imaging system  

DOEpatents

A system for providing an improved resolution retina image comprising an imaging camera for capturing a retina image and a computer system operatively connected to the imaging camera, the computer producing short exposures of the retina image and providing speckle processing of the short exposures to provide the improved resolution retina image. The system comprises the steps of capturing a retina image, producing short exposures of the retina image, and speckle processing the short exposures of the retina image to provide the improved resolution retina image.

Olivier, Scot S. (Livermore, CA); Carrano, Carmen J. (Livermore, CA)

2007-12-04

151

High resolution fire risk mapping in Italy  

NASA Astrophysics Data System (ADS)

The high topographic and vegetation heterogeneity makes Italy vulnerable to forest fires both in the summer and in winter. In particular, northern regions are predominantly characterized by a winter fire regime, mainly due to frequent extremely dry winds from the north, while southern and central regions and the large islands are characterized by a severe summer fire regime, because of the higher temperatures and prolonged lack of precipitation. The threat of wildfires in Italy is not confined to wooded areas as they extend to agricultural areas and urban-forest interface areas. The agricultural and rural areas, in the last century, have been gradually abandoned, especially in areas with complex topography. Many of these areas were subject to reforestation, leading to the spread of pioneer species mainly represented by Mediterranean conifer, which are highly vulnerable to fire. Because of the frequent spread of fire, these areas are limited to the early successional stages, consisting mainly of shrub vegetation; its survival in the competition with the climax species being ensured by the spread of fire itself. Due to the frequency of fire ignition almost entirely man caused the time between fires on the same area is at least an order of magnitude less than the time that would allow the establishment of forest climax species far less vulnerable to fire. In view of the limited availability of fire risk management resources, most of which are used in the management of national and regional air services, it is necessary to precisely identify the areas most vulnerable to fire risk. The few resources available can thus be used on a yearly basis to mitigate problems in the areas at highest risk by defining a program of forest management interventions, which is expected to make a significant contribution to the problem in a few years' time. The goal of such detailed planning is to dramatically reduce the costs associated with water bombers fleet management and fire extinguishing actions, leaving more resources to improve safety in areas at risk. With the availability of fire perimeters mapped over a period spanning from 5 to 10 years, depending by the region, a procedure was defined in order to assess areas at risk with high spatial resolution (900 m2) based on objective criteria by observing past fire events. The availability of fire perimeters combined with a detailed knowledge of topography and land cover allowed to understand which are the main features involved in forest fire occurrences and their behaviour. The seasonality of the fire regime was also considered, partitioning the analysis in two macro season (November- April and May- October). In addition, the total precipitation obtained from the interpolation of 30 years-long time series from 460 raingauges and the average air temperature obtained downscaling 30 years ERA-INTERIM data series were considered. About 48000 fire perimeters which burnt about 5500 km2 were considered in the analysis. The analysis has been carried out at 30 m spatial resolution. Some important considerations relating to climate and the territorial features that characterize the fire regime at national level contribute to better understand the forest fire phenomena. These results allow to define new strategies for forest fire prevention and management extensible to other geographical areas.

Fiorucci, Paolo; Biondi, Guido; Campo, Lorenzo; D'Andrea, Mirko

2014-05-01

152

High Spatial Resolution Commercial Satellite Imaging Product Characterization  

NASA Technical Reports Server (NTRS)

NASA Stennis Space Center's Remote Sensing group has been characterizing privately owned high spatial resolution multispectral imaging systems, such as IKONOS, QuickBird, and OrbView-3. Natural and man made targets were used for spatial resolution, radiometric, and geopositional characterizations. Higher spatial resolution also presents significant adjacency effects for accurate reliable radiometry.

Ryan, Robert E.; Pagnutti, Mary; Blonski, Slawomir; Ross, Kenton W.; Stnaley, Thomas

2005-01-01

153

High Resolution Scintillating Fiber Gamma Ray Detectors For Medical Imaging  

Microsoft Academic Search

High spatial and time resolution gamma ray detectors have been developed using plastic 'scintillating fibers coupled to position sensitive vacuum photomultipliers under development. These detectors can significantly improve the spatial resolution, time resolution, and efficiency of both SPECT and PET, extend the application of these technologies into new fields of medical research, and improve currently existing methods of medical diagnosis.

M. Atac; D. B. Cline; R. C. Chancy; E. J. Fenyves; G. Hademenos; P. P. Antich; M. D. Petroff

1990-01-01

154

Comparison of 3D Maximum A Posteriori and Filtered Backprojection algorithms for high resolution animal imaging in microPET  

SciTech Connect

We have evaluated the performance of two three dimensional reconstruction algorithms with data acquired from microPET, a high resolution tomograph dedicated to small animal imaging. The first was a linear filtered-backprojection algorithm (FBP) with reprojection of the missing data and the second was a statistical maximum-aposteriori probability algorithm (MAP). The two algorithms were evaluated in terms of their resolution performance, both in phantoms and in vivo. Sixty independent realizations of a phantom simulating the brain of a baby monkey were acquired, each containing 3 million counts. Each of these realizations was reconstructed independently with both algorithms. The ensemble of the sixty reconstructed realizations was used to estimate the standard deviation as a measure of the noise for each reconstruction algorithm. More detail was recovered in the MAP reconstruction without an increase in noise relative to FBP. Studies in a simple cylindrical compartment phantom demonstrated improved recovery of known activity ratios with MAP. Finally in vivo studies also demonstrated a clear improvement in spatial resolution using the MAP algorithm. The quantitative accuracy of the MAP reconstruction was also evaluated by comparison with autoradiography and direct well counting of tissue samples and was shown to be superior.

Chatziioannou, A.; Qi, J.; Moore, A.; Annala, A.; Nguyen, K.; Leahy, R.M.; Cherry, S.R.

2000-01-01

155

High time-resolution sprite observations  

NASA Astrophysics Data System (ADS)

Imaging sprites at 10,000 fps have revealed new details about their temporal development. TV observations show a highly structured central body with downward tendrils and upward branches. But rather than being leaders, as suggested by the long streaks in the TV recordings, tendrils and branches are actually formed by spatially compact streamer heads moving at velocities up to 0.3 c. In an individual sprite event the downward moving streamer heads start first forming the tendrils; later, and from a lower altitude and from existing luminous sprite structures, upward moving streamer heads may appear to form the branches. If there are no upward moving streamer heads the event would be classified as a C-sprite, otherwise it would be a carrot sprite. Following the streamer head activity we see afterglow in which little or no temporal and spatial activity is present. The streamer heads are very bright and they appear to be point sources, i.e. their spatial dimensions are less than our 100-200 m image resolution. Streamer head modeling indicates a scale size of ~25 m in which case the brightness would be in the range 1-100 GR. Other models predict volume emission rates leading to a streamer head spatial scale size in the 10 to 100 m range. Our observations conclusively show the downward and upward propagating streamer heads to be separated in time and space. This is in contrast to a number of models in which both down and up going streamer heads emanates from the origin of the process. We frequently see old sprites re-appear in response to new activity suggesting that sprite activity leaves some imprint on the background atmosphere. Given the very large brightness of the streamer heads it would not be surprising if sprite activity initiates chemical processes that could locally affect the composition of the atmosphere, but whether this affects the mesosphere on a larger scale remains uncertain.

Stenbaek-Nielsen, H. C.; McHarg, G. G.

2007-12-01

156

High Resolution Sensor for Nuclear Waste Characterization  

SciTech Connect

Gamma ray spectrometers are an important tool in the characterization of radioactive waste. Important requirements for gamma ray spectrometers used in this application include good energy resolution, high detection efficiency, compact size, light weight, portability, and low power requirements. None of the available spectrometers satisfy all of these requirements. The goal of the Phase I research was to investigate lanthanum halide and related scintillators for nuclear waste clean-up. LaBr3:Ce remains a very promising scintillator with high light yield and fast response. CeBr3 is attractive because it is very similar to LaBr3:Ce in terms of scintillation properties and also has the advantage of much lower self-radioactivity, which may be important in some applications. CeBr3 also shows slightly higher light yield at higher temperatures than LaBr3 and may be easier to produce with high uniformity in large volume since it does not require any dopants. Among the mixed lanthanum halides, the light yield of LaBrxI3-x:Ce is lower and the difference in crystal structure of the binaries (LaBr3 and LaI3) makes it difficult to grow high quality crystals of the ternary as the iodine concentration is increased. On the other hand, LaBrxCl3-x:Ce provides excellent performance. Its light output is high and it provides fast response. The crystal structures of the two binaries (LaBr3 and LaCl3) are very similar. Overall, its scintillation properties are very similar to those for LaBr3:Ce. While the gamma-ray stopping efficiency of LaBrxCl3-x:Ce is lower than that for LaBr3:Ce (primarily because the density of LaCl3 is lower than that of LaBr3), it may be easier to grow large crystals of LaBrxCl3-x:Ce than LaBr3:Ce since in some instances (for example, CdxZn1-xTe), the ternary compounds provide increased flexibility in the crystal lattice. Among the new dopants, Eu2+ and Pr3+, tried in LaBr3 host crystals, the Eu2+ doped samples exhibited low light output. This was mostly because a large fraction of light was emitted via very slow decay components (>50 ?¯??­s) and as a result was not included in the light estimation performed using gamma-ray spectroscopy where the typical amplifier integration time used is <12 ?¯??­s. The origin of these slow component(s) is most likely related to the presence of defects caused by charge imbalance in the crystals. The charge imbalance occurs when the Eu2+ ions replace the La3+ ions in crystal lattice. This charge neutrality can be restored by codoping the Eu2+ doped LaBr3 crystals with ions such as Hf4+. The Pr3+ doped LaBr3 crystals provided exciting results. They exhibited very high light yield (85,000 photons/MeV) and good energy resolution. While the decay time of LaBr3:Pr is much slower than that for LaBr3:Ce, it is fast enough for many nuclear waste cleanup applications. Furthermore, it should be possible to increase the speed of LaBr3:Pr by adjusting its Pr3+ concentration. The most exciting feature of LaBr3:Pr is that it emits in red-region and is therefore, well suited for silicon photodiode readout. In fact, LaBr3:Pr is the brightest scintillator in the red-region and its light yield is ~15% higher than the light yield of LaBr3 doped with Ce. Overall, the Phase I research has been very successful and has lead to better understanding of the lanthanum halide and related scintillators. It has also opened up some promising avenues to optimize the performance of these exciting scintillators. Based on the Phase I results, we have clearly demonstrated the feasibility of the proposed approach.

Mr. Kanai Shah; Mr. William Higgins; Dr. Edgar V. Van Loef

2006-01-23

157

High resolution bragg focusing optics for synchrotron monochromators and analyzers  

SciTech Connect

A number of different applications for high resolution Bragg Focusing Optics are reviewed. Applications include Sagittal Focusing, Energy Dispersive optics for x-ray absorption and diffraction, a curved analyzer-multichannel detector method for efficient acquisition of powder and small angle scattering data, the use of Backscattering Analyzers for very high resolution inelastic scattering, and curved crystals for high energy applications.

Knapp, G.S.; Beno, M.A.; Gofron, K.J.

1997-07-01

158

High-energy resolution, high-angular acceptance crystal monochromator  

SciTech Connect

The design principles, construction and characterization of a 4- bounce dispersive crystal monochromator is discussed. This monochromator is designed to reduce the bandpass of synchrotron radiation to 10--50 meV level, without sacrificing angular acceptance. This is achieved by combining an asymmetrically-cut, low order reflection with a symmetrically-cut, high order reflection in a nested configuration. This monochromator is being used as a beam conditioner for nuclear resonant scattering of synchrotron radiation to produce x-rays with [mu]eV[minus]neV resolution in the hard x-ray regime.

Toellner, T.S.; Mooney, T.; Alp, E.E. (Argonne National Lab., IL (United States)); Shastri, S. (Cornell Univ., Ithaca, NY (United States). Dept. of Applied Physics)

1992-06-01

159

High-energy resolution, high-angular acceptance crystal monochromator  

SciTech Connect

The design principles, construction and characterization of a 4- bounce dispersive crystal monochromator is discussed. This monochromator is designed to reduce the bandpass of synchrotron radiation to 10--50 meV level, without sacrificing angular acceptance. This is achieved by combining an asymmetrically-cut, low order reflection with a symmetrically-cut, high order reflection in a nested configuration. This monochromator is being used as a beam conditioner for nuclear resonant scattering of synchrotron radiation to produce x-rays with {mu}eV{minus}neV resolution in the hard x-ray regime.

Toellner, T.S.; Mooney, T.; Alp, E.E. [Argonne National Lab., IL (United States); Shastri, S. [Cornell Univ., Ithaca, NY (United States). Dept. of Applied Physics

1992-06-01

160

High resolution, high rate x-ray spectrometer  

DOEpatents

It is an object of the invention to provide a pulse processing system for use with detected signals of a wide dynamic range which is capable of very high counting rates, with high throughput, with excellent energy resolution and a high signal-to-noise ratio. It is a further object to provide a pulse processing system wherein the fast channel resolving time is quite short and substantially independent of the energy of the detected signals. Another object is to provide a pulse processing system having a pile-up rejector circuit which will allow the maximum number of non-interfering pulses to be passed to the output. It is also an object of the invention to provide new methods for generating substantially symmetrically triangular pulses for use in both the main and fast channels of a pulse processing system.

Goulding, F.S.; Landis, D.A.

1983-07-14

161

High spatial resolution restoration of IRAS images  

NASA Technical Reports Server (NTRS)

A general technique to improve the spatial resolution of the IRAS AO data was developed at The Aerospace Corporation using the Maximum Entropy algorithm of Skilling and Gull. The technique has been applied to a variety of fields and several individual AO MACROS. With this general technique, resolutions of 15 arcsec were achieved in 12 and 25 micron images and 30 arcsec in 60 and 100 micron images. Results on galactic plane fields show that both photometric and positional accuracy achieved in the general IRAS survey are also achieved in the reconstructed images.

Grasdalen, Gary L.; Inguva, R.; Dyck, H. Melvin; Canterna, R.; Hackwell, John A.

1990-01-01

162

High Resolution Velocity Structure in Eastern Turkey  

SciTech Connect

We investigate the crustal and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet and form a complex tectonic structure. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provided a unique opportunity for studying the high resolution velocity structure. Zor et al. found an average 46 km thick crust in Anatolian plateau using six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver function alone with many-layered parameterization may result in an apparent depth-velocity tradeoff. In order to improve previous velocity model, we employed the joint inversion method with many layered parameterization of Julia et al. (2000) to the ETSE receiver functions. In this technique, the receiver function and surface-wave observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. We consider azimuthal changes of receiver functions and have stacked them into different groups. We calculated the receiver functions using iterative time-domain deconvolution technique and surface wave group velocity dispersion curves between 10-100 sec. We are making surface wave dispersion measurements at the ETSE stations and have incorporated them into a regional group velocity model. Preliminary results indicate a strong trend in the long period group velocity in the northeast. This indicates slow upper mantle velocities in the region consistent with Pn, Sn and receiver function results. We started with both the 1-D model that is obtained with the 12 tones dam explosion shot data recorded by ETSE network and the existing receiver function inversion results. In fact, we observe that the inversion results are independent at the starting model and converges well to the same final model. We don't observe a significant change at the first order discontinuities of model (e.g. Moho depth), but we obtain better defined depths to low velocity layers.

Pasyanos, M; Gok, R; Zor, E; Walter, W

2004-09-03

163

High-Resolution, Single-Molecule  

E-print Network

, fluorescence reso- nance energy transfer, magnetic tweezers, atomic force microscopy, and optical traps-8700/07/0609-0171$20.00 Key Words optical trap, fluorescence, AFM, force clamp, magnetic tweezers Abstract Many biologically of Force on Molecular Motion and Resolution . . . . . . . . 177 Magnetic Tweezers

Woodside, Michael

164

10B concentration evaluation in autoradiography images by optical density measurements  

Microsoft Academic Search

The quantification and analysis of the tracks forming the autoradiography image of a tissue section is essential for the measurement of particle emitter concentration and distribution (e.g. 10B) in the sample. Conventional counting techniques cannot be used when track density is high because of track overlapping. A densitometry supported by image analysis method suitable for these cases has been developed.

A. Portu; G. Saint Martin; D. Brandizzi; O. A. Bernaola; R. L. Cabrini

2011-01-01

165

High Resolution Monochromatic X-Ray Tomography Using Synchrotron Radiation  

Microsoft Academic Search

We have improved the spatial resolution of X-ray computed tomographic (CT) images using monochromatic synchrotron radiation and a high resolution X-ray sensing pickup tube as a two-dimensional detector. The developed CT imaging system was used to observe nondestructively fine structures, such as cracks, and the chemical component distribution in a ceramic. A high resolution of 10 mum was obtained. The

Tatsumi Hirano; Katsuhisa Usami

1989-01-01

166

Drugs in the brain--cellular imaging with receptor microscopic autoradiography.  

PubMed

For cell and tissue localization of drugs, receptor microscopic autoradiography is reviewed, including its development history, multiple testing, extensive applications and significant discoveries. This sensitive high-resolution imaging method is based on the use of radiolabeled compounds (esp. tagged with (3)H or (125)I), preservation through freezing of in vivo localization of tissue constituents, cutting thin frozen sections, and close contact with the recording nuclear emulsion. After extensive testing of the utility of this method, the distribution of radiolabeled compounds has been identified and characterized for estradiol, progestagens, adrenal steroids, thyroid hormone, ecdysteroids, vitamin D, retinoic acid, metabolic indicators glucose and 2-deoxyglucose, as well as extracellular space indicators. Target cells and associated tissues have been characterized with special stains, fluorescing compounds, or combined autoradiography-immunocytochemistry with antibodies to dopamine-beta-hydroxylase, GABA, enkephalin, specific receptor proteins, or other cellular products. Blood-brain barrier and brain entries via capillary endothelium, ependyma, or circumventricular recess organs have been visualized for (3)H-dexamethasone, (210)Pb lead, and (3)H-1,25(OH)(2) vitamin D(3). With this histopharmacologic approach, cellular details and tissue integrative overviews can be assessed in the same preparation. As a result, information has been gained that would have been difficult or impossible otherwise. Maps of brain drug distribution have been developed and relevant target circuits have been recognized. Examples include the stria terminalis that links septal-amygdaloid-thalamic-hypothalamic structures and telencephalic limbic system components which extend as the periventricular autonomic-neuroendocrine ABC (Allocortex-Brainstem-Circuitry) system into the mid- and hindbrain. Discoveries with radiolabeled substances challenged existing paradigms, engendering new concepts and providing seminal incentives for further research toward understanding drug actions. Most notable are discoveries made during the 1980s with vitamin D in the brain together with over 50 target tissues that challenged the century-old doctrine of vitamin D's main role as 'the calcitropic hormone', when the new data made it apparent that the main biological function of this multifunctional sunshine hormone rather is maintenance of life and adapting vital functions to the solar environment. In the brain, vitamin D, in close relation to sex and adrenal steroids, participates in the regulation of the secretion of neuro-endocrines, such as, serotonin, dopamine, nerve growth factor, acetyl choline, with importance in prophylaxis and therapy of neuro-psychiatric disorders. Histochemical imaging with high cellular-subcellular resolution is necessary for obtaining detailed information, as this review indicates. New spectrometric methods, like MALDI-MSI, are unlikely to furnish the same information as receptor microautoradiography does, but can provide important correlative molecular information. PMID:22240062

Stumpf, Walter E

2012-03-01

167

Resolution improvement using tapered fiber for a high resolution PET block detector  

Microsoft Academic Search

A tapered fiber optical plate (tapered fiber) is a fiber optical plate in which input size and output size is different. A tapered fiber can magnify the light photon image with low light loss. The tapered fiber may be a useful component for a high resolution positron emission tomograph (PET) block detector. Thus, investigations on resolution improvement were performed by

S. Yamamoto

1998-01-01

168

Exchange Bias Systems studied by High Resolution Quantitative Magnetic Force  

E-print Network

Exchange Bias Systems studied by High Resolution Quantitative Magnetic Force Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2 Introduction to Quantitative MFM 12 2.1 Magnetic Force Microscope study F/AF heterostructure-samples by VSM and quantitative, high resolution MFM. MFM works in magnetic

Amrhein, Valentin

169

Advances in high-resolution imaging from underwater vehicles  

Microsoft Academic Search

Large area mapping at high resolution underwater continues to be constrained by the mismatch between available navigation as compared to sensor accuracy. In this paper we present advances that exploit consistency and redundancy within local sensor measurements to build high resolution optical and acoustic maps that are a consistent representation of the environment.

We present our work in the context of

Hanumant Singh; Christopher Roman; Oscar Pizarro; Ryan Eustice

2005-01-01

170

High-resolution radar imagery of the Mirage III aircraft  

Microsoft Academic Search

High-resolution radar imagery has attracted increasing interest in recent years. As more radars are endowed with a high-resolution capability, target classification will become a regular system function. In order to classify an aircraft using radar, one must have an understanding of how the radar imagery relates to the physical aircraft. This paper illustrates the more important radar backscattering features on

A. Zyweck; R. E. Bogner

1994-01-01

171

HETEROGENEOUS CLUTTER MODEL FOR HIGH RESOLUTION POLARIMETRIC SAR DATA PROCESSING  

E-print Network

HETEROGENEOUS CLUTTER MODEL FOR HIGH RESOLUTION POLARIMETRIC SAR DATA PROCESSING G. Vasile1 , F a new estimation scheme for optimally deriving clutter parameters with high resolution POLSAR data. The heterogeneous clutter in POLSAR data is described by the Spherically Invariant Random Vectors model. Three

Paris-Sud XI, Université de

172

High resolution x-ray microscope  

SciTech Connect

The authors present x-ray images of grid meshes and biological material obtained using a microspot x-ray tube with a multilayer optic and a 92-element parabolic compound refractive lens (CRL) made of a plastic containing only hydrogen and carbon. Images obtained using this apparatus are compared with those using an area source with a spherical lens and a spherical lens with multilayer condenser. The authors found the best image quality using the multilayer condenser with a parabolic lens, compared to images with a spherical lens and without the multilayer optics. The resolution was measured using a 155-element parabolic CRL and a multilayer condenser with the microspot tube. The experiment demonstrates about 1.1 {mu}m resolution.

Gary, C. K.; Park, H.; Lombardo, L. W.; Piestrup, M. A.; Cremer, J. T.; Pantell, R. H.; Dudchik, Y. I. [Adelphi Technology, Inc. 981-B Industrial Road, San Carlos, California 94070 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Institute of Applied Physics Problems, Kurchatova 7, Minsk 220064 (Belarus)

2007-04-30

173

The high resolution spaghetti hadron calorimeter  

NASA Astrophysics Data System (ADS)

It is proposed to build a prototype for a hadron calorimeter with scintillating plastic fibers as active material. The absorber material is lead. Provided that these components are used in the appropriate volume ratio, excellent performance may be expected, e.g., an energy resolution of 30%/rtE for jet detection. The proposed design offers additional advantages compared to the classical sandwich calorimeter structures in terms of granularity, hermiticity, uniformity, compactness, readout, radiation resistivity, stability, and calibration.

Jenni, P.; Sonderegger, P.; Paar, H. P.; Wigmans, R.

174

High resolution, high bandwidth global shutter CMOS area scan sensors  

NASA Astrophysics Data System (ADS)

Global shuttering, sometimes also known as electronic shuttering, enables the use of CMOS sensors in a vast range of applications. Teledyne DALSA Global shutter sensors are able to integrate light synchronously across millions of pixels with microsecond accuracy. Teledyne DALSA offers 5 transistor global shutter pixels in variety of resolutions, pitches and noise and full-well combinations. One of the recent generations of these pixels is implemented in 12 mega pixel area scan device at 6 um pitch and that images up to 70 frames per second with 58 dB dynamic range. These square pixels include microlens and optional color filters. These sensors also offer exposure control, anti-blooming and high dynamic range operation by introduction of a drain and a PPD reset gate to the pixel. The state of the art sense node design of Teledyne DALSA's 5T pixel offers exceptional shutter rejection ratio. The architecture is consistent with the requirements to use stitching to achieve very large area scan devices. Parallel or serial digital output is provided on these sensors using on-chip, column-wise analog to digital converters. Flexible ADC bit depth combined with windowing (adjustable region of interest, ROI) allows these sensors to run with variety of resolution/bandwidth combinations. The low power, state of the art LVDS I/O technology allows for overall power consumptions of less than 2W at full performance conditions.

Faramarzpour, Naser; Sonder, Matthias; Li, Binqiao

2013-10-01

175

Survey of currently available high-resolution raster graphics systems  

NASA Technical Reports Server (NTRS)

Presented are data obtained on high-resolution raster graphics engines currently available on the market. The data were obtained through survey responses received from various vendors and also from product literature. The questionnaire developed for this survey was basically a list of characteristics desired in a high performance color raster graphics system which could perform real-time aircraft simulations. Several vendors responded to the survey, with most reporting on their most advanced high-performance, high-resolution raster graphics engine.

Jones, Denise R.

1987-01-01

176

DSCOVR High Time Resolution Solar Wind Measurements  

NASA Technical Reports Server (NTRS)

The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.

Szabo, Adam

2012-01-01

177

High resolution integral holography using Fourier ptychographic approach.  

PubMed

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. PMID:25607162

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

2014-12-29

178

High-resolution studies of atmospheric IR emission spectra  

NASA Technical Reports Server (NTRS)

Atmospheric emission spectra obtained with two different spectrometer systems are presented. The first system (the BOMEM Michelson interferometer) is designed for emission work. Spectra were obtained under adverse conditions in the Antarctic, and are still of good absolute accuracy. The second system (a modified Bruker Instruments IFS120 very high spectral resolution interferometer) demonstrates the sensitivity that can be achieved even at higher spectral resolution. This system shows that mid-IR atmospheric emission spectra can be obtained with a good SNR in a reasonable length of time at a relatively high resolution. A properly designed high resolution system should achieve high accuracy, sensitivity, and resolution, thereby permitting measurements of many atmospheric constituents when solar spectra cannot be obtained.

Murcray, F. J.; Murcray, F. H.; Goldman, A.; Blatherwick, R. D.; Murcray, D. G.

1991-01-01

179

Design of a high resolution scintillator based SPECT detector (SPECTatress)  

NASA Astrophysics Data System (ADS)

SPECT scanners using multi-pinhole collimators benefit from compact detectors having a high spatial resolution. Such detectors can be placed closer to the collimator and perpendicular to the pinhole axis (thereby limiting DOI spatial resolution degradation). Current clinical gamma ray cameras have a large area and a poor spatial resolution.This proceeding describes the architecture of SPECTatress, a compact high resolution gamma camera. The main components (PMT and scintillator) are presented, a brief overview of the read-out electronics is given and a first measurement using the center-of-gravity (COG) event-positioning algorithm is shown.The result of this measurement indicates a good spatial resolution (1.75 mm FWHM) in the center of the detector. Further research has to be done on the event-positioning algorithm to extend the usable detector area and to enhance the spatial resolution.

Deprez, Karel; van Holen, Roel; Vandenberghe, Stefaan; Staelens, Steven

2011-08-01

180

Modelling high resolution RS data with the aid of coarse resolution data and ancillary data  

NASA Astrophysics Data System (ADS)

In environmental applications, the data have a large variety of resolutions carrying information at different scales. Various approaches have been used to include in models information from sources at different scales combining multi-resolution products in order to integrate the spatio-temporal variability of sub-pixel pattern. A methodology is proposed for the integration of the results obtained with a geostatistical downscaling algorithm, based on block-to-point-kriging, in a General Additive Models interpolation framework to enhance the spatio-temporal resolution of remote sensing data. This allows a good reproduction of the overall spatial pattern of the target images and of their local values. The developed framework was tested using MODIS land surface temperature (LST) with the thermal band of Landsat in a situation of high contamination of clouds for the high resolution dataset. The method proved to be flexible and able to blend data from different sensors maintaining the finer spatial structure of the higher resolution data. The method combines strengths from different approaches: (1) it uses of information held in covariates to provide more accurate results; (2) it is applicable to a variety of remote sensing products as the method does not rely on predetermined functional relationships; (3) it can cope with cloud-rich high resolution images as only a subset of high resolution pixels is needed. This approach is general and can be used with numerous combinations of high and low resolution images, such as MODIS-derived variables, using related band ratios from Landsat or other higher resolution sensors. This approach is a valuable addition to space-time measuring and modelling of ecosystems functions from remote sensing.

Poggio, Laura; Gimona, Alessandro

2013-08-01

181

High resolution airborne geophysics at hazardous waste disposal sites  

SciTech Connect

In 1994, a high resolution helicopter geophysical survey was conducted over portions of the Oak Ridge Reservation, Tennessee. The 1800 line kilometer survey included multi-frequency electromagnetic and magnetic sensors. The areas covered by the high resolution portion of the survey were selected on the basis of their importance to the environmental restoration effort and on data obtained from the reconnaissance phase of the airborne survey in which electromagnetic, magnetic, and radiometric data were collected over the entire Oak Ridge Reservation in 1992--1993. The high resolution phase had lower sensor heights, more and higher EM frequencies, and tighter line spacings than did the reconnaissance survey. When flying over exceptionally clear areas, the high resolution bird came within a few meters of the ground surface. Unfortunately, even sparse trees and power or phone lines could prevent the bird from being towed safely at low altitude, and over such areas it was more usual for it to be flown at about the same altitude as the bird in the reconnaissance survey, about 30m. Even so, the magnetometers used in the high resolution phase were 20m closer to the ground than in the reconnaissance phase because they were mounted on the tail of the bird rather than on the tow cable above the bird. The EM frequencies used in the high resolution survey ranged from 7400Hz to 67000Hz. Only the horizontal coplanar loop configuration was used in the high resolution flyovers.

Beard, L.P.; Nyquist, J.E.; Doll, W.E. [Oak Ridge National Lab., TN (United States); Chong Foo, M.; Gamey, T.J. [Aerodat, Inc., Mississauga, Ontario (Canada)

1995-06-01

182

Very high resolution spectroscopy of high Rydberg states  

NASA Astrophysics Data System (ADS)

Atomic and molecular Rydberg states in the range of principal quantum number n=100-500 have unusual properties: The classical orbits are extremely large (diameter larger than 1 ? m); the Rydberg electron is very weakly bound (by less than 1 meV); moreover, atoms and molecules in high Rydberg states are extremely sensitive to their environment and respond strongly to even small perturbations such as those induced by weak (stray) electric fields or particles located in their vicinity (T.F. Gallagher, Rydberg atoms) (Cambridge University Press, Cambridge, 1994),Rydberg states of atoms and molecules, Eds. R.F. Stebbings and F.B. Dunning (Cambridge University Press, Cambridge, 1983). The unusual properties of high Rydberg states are at the origin of the success of several new spectroscopic techniques, such as pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectroscopy and mass-analysed theshold ionization (MATI) spectroscopy, that have been developed recently to study molecular ions (K. Mller- Dethlefs and E. W. Schlag, Ann. Rev. Phys. Chem.) 42, 109 (1991), F. Merkt Ann. Rev. Phys. Chem. 48, 675 (1997). These techniques, which are used in an increasing number of laboratories, rely on the pulsed field ionization of high Rydberg states (n=100-500) located immediately below successive ionization thresholds in a molecule. Although possible impacts of uncontrolled external perturbations on the appearance of PFI-ZEKE spectra have been inferred recently (W.A. Chupka, J. Chem. Phys.) 98 4520 (1993), F. Merkt and R.N. Zare, J. Chem. Phys. 101 3495 (1994), these remain very difficult to assess: The experimental efforts needed to reduce, or at least quantify, the effects of stray electric fields and external perturbations on Rydberg states beyond n=100 are considerable and have not even been attempted so far by PFI-ZEKE and MATI spectroscopists. To fill in this gap, a new instrument has been developed to obtain very high resolution (250 kHz) spectra of molecular and atomic Rydberg states in the range of principal quantum number n=30-300 using a double resonance technique. Key components of the instrument are a high-resolution, broadly tunable (10-20 eV) extreme ultraviolett (XUV) laser system and a frequency stabilized source of millimeter waves. Selected results illustrating the capabilities of this instrument will be presented. First, a simple procedure (M. T. Frey, X. Ling, B. G. Lindsay, K. A. Smith and F. B. Dunning, Rev. Sci. Instrum.) 64 3649 (1993), based on the analysis of spectral line shifts of high Rydberg states as a function of electric field strength, is used to measure stray electric fields with an absolute accuracy of 50 ? V/cm and to subsequently compensate them, enabling the reduction of stray electric fields to less than 50 ?V/cm. Second, the analysis of spectral line shapes as a function of laser power is used to obtain distributions of electric field strengths as a function of the ion concentration in the experimental volume. Third, fully resolved Stark maps of high Rydberg states of krypton are obtained at n? 100 below the ^2P_3/2 ionization threshold. Finally, high precision measurement of the fine-structure splittings in p, d and f Rydberg states of the argon and the krypton atoms are reported. The hyperfine structure in high Rydberg states of the ^83Kr isotope has also been fully resolved. The implications of these results for PFI-ZEKE and MATI spectroscopy will be discussed.

Merkt, F.

1998-05-01

183

Wide-field, high-resolution Fourier ptychographic microscopy  

NASA Astrophysics Data System (ADS)

We report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field, high-resolution complex sample image. By adopting a wavefront correction strategy, the FPM method can also correct for aberrations and digitally extend a microscope's depth of focus beyond the physical limitations of its optics. As a demonstration, we built a microscope prototype with a resolution of 0.78 m, a field of view of ~120 mm2 and a resolution-invariant depth of focus of 0.3 mm (characterized at 632 nm). Gigapixel colour images of histology slides verify successful FPM operation. The reported imaging procedure transforms the general challenge of high-throughput, high-resolution microscopy from one that is coupled to the physical limitations of the system's optics to one that is solvable through computation.

Zheng, Guoan; Horstmeyer, Roarke; Yang, Changhuei

2013-09-01

184

Wide-field, high-resolution Fourier ptychographic microscopy.  

PubMed

In this article, we report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field, high-resolution complex sample image. By adopting a wavefront correction strategy, the FPM method can also correct for aberrations and digitally extend a microscope's depth-of-focus beyond the physical limitations of its optics. As a demonstration, we built a microscope prototype with a resolution of 0.78 ?m, a field-of-view of ~120 mm(2), and a resolution-invariant depth-of-focus of 0.3 mm (characterized at 632 nm). Gigapixel colour images of histology slides verify FPM's successful operation. The reported imaging procedure transforms the general challenge of high-throughput, high-resolution microscopy from one that is coupled to the physical limitations of the system's optics to one that is solvable through computation. PMID:25243016

Zheng, Guoan; Horstmeyer, Roarke; Yang, Changhuei

2013-09-01

185

[Development of a high resolution simultaneous microwave plasma torch spectrometer].  

PubMed

A unique high resolution simultaneous microwave plasma torch (MPT) atomic emission spectrometer was developed and studied preliminarily. Some advanced technologies were applied to the spectrometer, such as echelle grating, UV-intensified CCD array detector, adjustable microwave generator, and water cooling system for the generator, etc. The detection limits of the spectrometer for some elements were determined, the spectral resolution and pixel resolution of the spectrometer were calculated, and an analysis of a practical sample was carried out. The preliminary results demonstrate that such simultaneous spectrometer has advantages of saving sample and time, possessing high sensitivity and resolution, and low-cost for the purchase and maintenance. Taking analytical figures of merit into consideration, the high resolution simultaneous MPT spectrometer will have extended application areas and greater competition potential as compared with sequential MPT spectrometers. PMID:18260435

Jiang, Jie; Huan, Yan-Fu; Jin, Wei; Feng, Guo-Dong; Fei, Qiang; Cao, Yan-Bo; Jin, Qin-Han

2007-11-01

186

High Resolution Multimode Fiber Image Recovery  

NASA Technical Reports Server (NTRS)

The research emphasis is on developing a cost-effective method of recovering image information from small, closely confined spaces using multimode fibers. The state-of-the-art good quality-viewing fiber, which can currently be used for performing this function, is a 0.5 mm diameter bundle containing 6000 pixels at a cost of $10,000 per fiber bundle. However, these fiber bundles are very fragile and can easily break during surgical use, thereby making instrument reliability and replacement cost,a major impediment to their routine use in many applications. The advantage of working with a single multimode fiber is that it is significantly less expensive and mechanically more robust. In addition, careful choice of numerical aperture allows a higher image resolution (roughly 750,000 pixels) with a 0.5 mm diameter multimode fiber.

Jackson, Deborah

2000-01-01

187

Galileo high-resolution encoder system  

NASA Astrophysics Data System (ADS)

The Galileo National Telescope (TNG) is a 3.6 meter Alt-Az telescope installed at the Astronomical Observatory of the Roque de Los Muchachos in La Palma, Canary Islands (Spain). The TNG motion control system, designed and realized by the Technology Working Group (TWG), is completely digital because of the versatility of this system topology. In a digital control system using an encoder as transducer means to have a digital feedback signal, therefore directly comparable with the reference without any conversion that is essential with other kinds of transducers. In the following the Galileo telescope (TNG) encoder system with its control electronics and the management software are described. It has been realized by a collaboration between the Heidenhain Company and the TWG. The TNG encoder system, at the state of the art, has one of the highest performances in the telescopes field, in terms of resolution, accuracy, readout time, reliability.

Mancini, Dario; Cascone, Enrico; Schipani, Pietro

1997-09-01

188

A high resolution global scale groundwater model  

NASA Astrophysics Data System (ADS)

As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and also supplies water for agricultural and industrial activities. During times of drought, the large natural groundwater storage provides a buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a transient global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Drr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013) combined with information about e.g. aquifer thickness and presence of less permeable, impermeable, and semi-impermeable layers. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. We validated simulated groundwater heads with observations, from North America and Australia, resulting in a coefficient of determination of 0.8 and 0.7 respectively. This shows that it is feasible to build a global groundwater model using best available global information, and estimated water table depths are within acceptable accuracy in many parts of the world.

de Graaf, I. E.; Sutanudjaja, E.; Van Beek, L. P.; Bierkens, M. F.

2013-12-01

189

High-resolution imaging using ultrasound-modulated optical tomography  

Microsoft Academic Search

We present an implementation of ultrasound-modulated optical tomography that has the potential to provide high resolution images of tissue structures at a penetration depth of several millimeters. Light and pulsed ultrasound are focused on an approximately 100 mum wide area below the sample surface. With this configuration, the length of the ultrasonic pulses determines the axial resolution, and the lateral

Sava Sakadzic; Konstantin Maslov; Jun Li; Vikram K. Kinra; Lihong V. Wang

2004-01-01

190

A high resolution scintillating fiber gamma-ray telescope  

Microsoft Academic Search

Scintillating fibers coupled to position sensitive photomultipliers have good angular precision and good energy resolution in detecting gamma-rays. Scintillating fibers stacked up into scintillating fiber planes U, V and W that are rotated by 60 angle relative to each other and coupled to position sensitive photomultipliers can be used as high resolution imaging gamma-ray detectors. With this arrangement the Compton

M. Atac; D. B. Cline; E. J. Fenyves; R. C. Chaney; H. Hammack

1989-01-01

191

HIGH-RESOLUTION SEISMIC TOMOGRAPHY BASED ON COHERENT WAVE TECHNOLOGIES  

Microsoft Academic Search

A brand-new high-resolution seismic tomography method is presented. In spite of its great achievements, conventional seismic tomography, which is based on travel time data, has been suffering from low resolution. As an alternative, we have been trying an active seismic tomography based on accurate harmonic wave. Our source is an oscillator that is an eccentric mass driven by a servomotor.

Hiromichi Higashihara; Masayuki Saeki; Zeng WeiJian

192

Mapping cognitive brain function with modern high-resolution electroencephalography  

Microsoft Academic Search

High temporal resolution is necessary to resolve the rapidly changing patterns of brain activity that underlie mental function. While electroencephalography (EEG) provides temporal resolution in the millisecond range, which would seem to make it an ideal complement to other imaging modalities, traditional EEG technology and practice provides insufficient spatial detail to identify relationships between brain electrical events and structures and

Alan Gevins; Harrison Leong; Michael E. Smith; Jian Le; Robert Du

1995-01-01

193

High spectral resolution multiplex CARS spectroscopy using chirped pulses  

Microsoft Academic Search

A simple technique for achieving high spectral resolution coherent anti-Stokes Raman scattering (CARS) spectra with a femtosecond laser system is presented. A linearly chirped and stretched (?10 ps) pump pulse generates CARS signal only when overlapped in time with the Stokes pulse (90 fs), creating a `temporal slit' that defines the spectral resolution of the technique. Multiplex CARS spectra for

K. P. Knutsen; J. C. Johnson; A. E. Miller; P. B. Petersen; R. J. Saykally

2004-01-01

194

A HIGH RESOLUTION FULL EARTH DISK MODEL FOR MICROWAVE  

E-print Network

A HIGH RESOLUTION FULL EARTH DISK MODEL FOR MICROWAVE OBSERVATIONS FROM GEO Boon H Lim1 transfer model that also accounts for the propagation and viewing geometries from GEO. The resulting model simulates full disk microwave images with the highest known resolution. The model can be used in concert

Ruf, Christopher

195

Ultrastable reference pulser for high-resolution spectrometers  

NASA Technical Reports Server (NTRS)

Solid-state double-pulse generator for a high resolution semiconductor detector meets specific requirements for resolution /0.05 percent/, amplitude range /0.1-13 MeV/, and repetition rate /0.1-1000 pulses per second/. A tag pulse is generated in coincidence with each reference pulse.

Brenner, R.; Lenkszus, F. R.; Sifter, L. L.; Strauss, M. G.

1970-01-01

196

Cheetah: A high frame rate, high resolution SWIR image camera  

NASA Astrophysics Data System (ADS)

A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 ?m] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

2008-10-01

197

Sensitivity of urban hydrodynamic modelling to high resolution radar rainfall  

NASA Astrophysics Data System (ADS)

Since the early 90's, the need to improve the spatial and temporal resolution of rainfall estimates has been emphasised. Urban hydrological applications require high resolution rainfall inputs matching rapid response times of such catchments. With the advent of new radar technology, urban hydrologists nowadays have access to highly accurate rainfall estimates to drive their models. High resolution rainfall products are provided by dual polarimetric X-band radars, which retrieve rainfall rates at 1 min temporal resolution and 30 m spatial resolution. This study attempts to characterise sensitivity of hydrologic response to high resolution weather radar rainfall input for hydrodynamic models at urban scale. Spatial resolutions of both rainfall input and hydrologic units are of the order of 100 meters. Rainfall rates derived from X-band polarimetric weather radar are used as input into a detailed hydrodynamic sewer model for an urban catchment in Rotterdam, The Netherlands. Rainfall data of two storms, one convective and one stratiform, at different spatial resolutions, are used to analyse the effect of precipitation data resolution on simulated in-sewer water levels as well as runoff peaks. Dimensionless parameters are derived to analyse the effect of rainfall resolution in relation to storm and catchment properties. Simulation results are first analysed in relation to 'storm redistribution' induced by spatial precipitation sampling: storm correlation distance is compared to rainfall resolution and the effect on hydrodynamic model results is discussed. Sensitivity of hydrodynamic model results to storm redistribution will be discussed for varying positions throughout the catchment and dependent on localisation of convective storm cells.

Bruni, Guendalina; Reinoso, Ricardo; van de Giesen, Nick; Clemens, Francois; ten Veldhuis, Marie-Claire

2014-05-01

198

Resolution analysis of high-resolution marine seismic data acquired off Yeosu, Korea  

NASA Astrophysics Data System (ADS)

High-resolution marine seismic surveys have been conducted for the mineral exploration and engineering purpose survey. To improve the quality of high-resolution seismic data, small-scaled multi-channel seismic techniques are used. In this study, we designed high-resolution marine seismic survey using a small airgun and an 8-channel streamer cable and analyzed the resolution of the seismic data related to acquisition and processing parameters. The field survey was conducted off Yeosu, Korea where the stratified thin sedimentary layers are deposited. We used a 30 in3 airgun and an 8-channel streamer cable with a 5 m group interval. We shoot the airgun with a 5 m shot interval and recorded digital data with a 0.1 ms sample interval and 1 s record length. The offset between the source and the first channel was 20 m. We processed the acquired data with simple procedure such as gain recovery, deconvolution, digital filtering, CMP sorting, NMO correction, static correction and stacking. To understand the effect of the acquisition parameters on the vertical and horizontal resolution, we resampled the acquired data using various sample intervals and CMP intervals and produced seismic sections. The analysis results show that the detailed subsurface structures can be imaged with good resolution and continuity using acquisition parameters with a sample interval shorter than 0.2 ms and a CMP interval shorter than 2.5 m. A high-resolution marine 8-channel airgun seismic survey using appropriate acquisition and processing parameters can be effective in imaging marine subsurface structure with a high resolution. This study is a part of a National Research Laboratory (NRL) project and a part of an Energy Technology Innovation (ETI) Project of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), funded by the Ministry of Trade, Industry and Energy (MOTIE). The authors thank the officers and crew of the R/V Tamhae II for their efforts in the field survey.

Lee, Ho-Young; Kim, Wonsik; Koo, Nam-Hyung; Park, Keun-Pil; Yoo, Dong-Geun; Kang, Dong-Hyo; Kim, Young-Gun; Seo, Gab-Seok; Hwang, Kyu-Duk

2014-05-01

199

A high resolution global scale groundwater model  

NASA Astrophysics Data System (ADS)

As the world's largest accessible source of freshwater, groundwater plays a vital role in satisfying the basic needs of human society. It serves as a primary source of drinking water and supplies water for agricultural and industrial activities. During times of drought, groundwater storage provides a large natural buffer against water shortage and sustains flows to rivers and wetlands, supporting ecosystem habitats and biodiversity. Yet, the current generation of global scale hydrological models (GHMs) do not include a groundwater flow component, although it is a crucial part of the hydrological cycle. Thus, a realistic physical representation of the groundwater system that allows for the simulation of groundwater head dynamics and lateral flows is essential for GHMs that increasingly run at finer resolution. In this study we present a global groundwater model with a resolution of 5 arc-minutes (approximately 10 km at the equator) using MODFLOW (McDonald and Harbaugh, 1988). With this global groundwater model we eventually intend to simulate the changes in the groundwater system over time that result from variations in recharge and abstraction. Aquifer schematization and properties of this groundwater model were developed from available global lithological maps and datasets (Drr et al., 2005; Gleeson et al., 2010; Hartmann and Moosdorf, 2013), combined with our estimate of aquifer thickness for sedimentary basins. We forced the groundwater model with the output from the global hydrological model PCR-GLOBWB (van Beek et al., 2011), specifically the net groundwater recharge and average surface water levels derived from routed channel discharge. For the parameterization, we relied entirely on available global datasets and did not calibrate the model so that it can equally be expanded to data poor environments. Based on our sensitivity analysis, in which we run the model with various hydrogeological parameter settings, we observed that most variance in groundwater depth is explained by variation in saturated conductivity, and, for the sediment basins, also by variation in recharge. We validated simulated groundwater heads with piezometer heads (available from www.glowasis.eu), resulting in a coefficient of determination for sedimentary basins of 0.92 with regression constant of 0.8. This shows the used method is suitable to build a global groundwater model using best available global information, and estimated water table depths are within acceptable accuracy in many parts of the world.

de Graaf, Inge; Sutanudjaja, Edwin; van Beek, Rens; Bierkens, Marc

2014-05-01

200

Method for obtaining a high resolution protein map starting from a low resolution map.  

PubMed Central

A method is described for estimating the phases of high resolution single-crystal diffraction data from proteins, by using as a starting point a set of low resolution phases (about 3 A) derived by multiple isomorphous replacement (or other) methods. The method consists in refining by least-squares the positions and thermal parameters of a set of dummy atoms placed in the initial low resolution electron density map, so as to minimize the discrepancy between the calculated scattering intensities and the scattering intensities observed in the high resolution data set. Phases calculated from these refined atomic positions are used to extend the resolution and to improve the quality of the electron density map. The success of the method depends on a new least-squares algorithm that has a radius of convergence of about 0.75 A. This large radius of convergence, together with the severe restrictions placed on the initial positions of the dummy atoms by the requirement that they lie within limited regions of the isomorphous electron density map, and the constraint imposed by the polymeric nature of a polypeptide chain account for the success of the method. The method has been successfully used to phase the structure factors of 2-zinc insulin at a resolution of 2 A and 1.5 A, starting from a set of isomorphous phases at 3-A resolution. PMID:268634

Agarwal, R C; Isaacs, N W

1977-01-01

201

Ultra-high resolution and high-brightness AMOLED  

NASA Astrophysics Data System (ADS)

As part of its continuing effort to improve both the resolution and optical performance of AMOLED microdisplays, eMagin has recently developed an SXGA (128031024) microdisplay under a US Army RDECOM CERDEC NVESD contract that combines the world's smallest OLED pixel pitch with an ultra-high brightness green OLED emitter. This development is aimed at next-generation HMD systems with "see-through" and daylight imaging requirements. The OLED pixel array is built on a 0.18-micron CMOS backplane and contains over 4 million individually addressable pixels with a pixel pitch of 2.7 8.1 microns, resulting in an active area of 0.52 inches diagonal. Using both spatial and temporal enhancement, the display can provide over 10-bits of gray-level control for high dynamic range applications. The new pixel design also enables the future implementation of a full-color QSXGA (2560 RGB 2048) microdisplay in an active area of only 1.05 inch diagonal. A low-power serialized low-voltage-differential-signaling (LVDS) interface is integrated into the display for use as a remote video link for tethered systems. The new SXGA backplane has been combined with the high-brightness green OLED device developed by eMagin under an NVESD contract. This OLED device has produced an output brightness of more than 8000fL with all pixels on; lifetime measurements are currently underway and will presented at the meeting. This paper will describe the operational features and first optical and electrical test results of the new SXGA demonstrator microdisplay.

Wacyk, Ihor; Ghosh, Amal; Prache, Olivier; Draper, Russ; Fellowes, Dave

2012-06-01

202

Utilizing high resolution and reconfigurable patterns in combination with inkjet printing to produce high performance circuits  

NASA Astrophysics Data System (ADS)

Inkjet printing on pre-fabricated high-resolution substrate is developed to improve the operational speed of printed organic transistors. The high-resolution features are designed to define transistor critical dimensions, while maintaining the flexibility to incorporate different circuit constructions. Logic gate and ring oscillator circuits fabricated by inkjet printing on the high-resolution substrate are demonstrated, to show that the same high resolution pattern can be adapted for constructing different electronic circuits.

Mei, P.; Ng, T. N.; Lujan, R. A.; Schwartz, D. E.; Kor, S.; Krusor, B. S.; Veres, J.

2014-09-01

203

Sensitivity study of reliable, high-throughput resolution metricsfor photoresists  

SciTech Connect

The resolution of chemically amplified resists is becoming an increasing concern, especially for lithography in the extreme ultraviolet (EUV) regime. Large-scale screening and performance-based down-selection is currently underway to identify resist platforms that can support shrinking feature sizes. Resist screening efforts, however, are hampered by the absence of reliable resolution metrics that can objectively quantify resist resolution in a high-throughput fashion. Here we examine two high-throughput metrics for resist resolution determination. After summarizing their details and justifying their utility, we characterize the sensitivity of both metrics to two of the main experimental uncertainties associated with lithographic exposure tools, namely: limited focus control and limited knowledge of optical aberrations. For an implementation at EUV wavelengths, we report aberration and focus limited error bars in extracted resolution of {approx} 1.25 nm RMS for both metrics making them attractive candidates for future screening and down-selection efforts.

Anderson, Christopher N.; Naulleau, Patrick P.

2007-07-30

204

A temperature-compensated high spatial resolution distributed strain sensor  

Microsoft Academic Search

We propose and demonstrate a scheme which utilizes the temperature dependence of spontaneous Raman scattering to provide temperature compensation for a high spatial resolution Brillouin frequency-based strain sensor.

Mohammad Belal; Yuh Tat Cho; Morten Ibsen; Trevor P. Newson

2010-01-01

205

Absolute shape measurements using high-resolution optoelectronic holography methods  

E-print Network

Absolute shape measurements using high- resolution optoelectronic holography methods Cosme Furlong optoelectronic holography (OEH) methodology is described. This description addresses apparatus and analysis holography; shape and deformation measurements; surface tiling. Paper SM-26 received July 30, 1999; revised

Furlong, Cosme

206

High Resolution CryoFESEM of Microbial Surfaces  

NASA Astrophysics Data System (ADS)

The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at [minus sign]125C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to cracking of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.

Erlandsen, Stanley; Lei, Ming; Martin-Lacave, Ines; Dunny, Gary; Wells, Carol

2003-08-01

207

Infrared Land Surface Remote Sensing using High Spectral Resolution Observations  

NASA Astrophysics Data System (ADS)

The authors will describe results of combining high spectral resolution infrared observations with high spatial resolution observations to provide an improved assessment of land surface characteristics. In particular, the high spectral resolution observations of the airborne Scanning-High-resolution Interferometer Sounder (S-HIS)and NPOESS Airborne Sounder Testbed - Interferometer (NAST-I) will be used to derive land surface temperature and infrared emissivity measurements. The MODIS Airborne Simulator (MAS) observations will be used to quantify the sub-pixel land surface variability. Ground truth observations from the Atmospheric Emitted Radiance Interferometer will be presented. The remote sensing techniques will be extended to the satellite based observations of the Interferometeric Monitor for greenhouse Gases (IMG) as well as to simulations of the AIRS and MODIS measurements from the NASA EOS Aqua platform.

Knuteson, R.; Deslover, D.; Larar, A.; Osborne, B.; Revercomb, H.; Short, J.; Smith, W.; Tanamachi, R.

208

Development of a high-resolution alpha camera  

Microsoft Academic Search

We have developed and tested a high-resolution alpha camera. The alpha camera consists of a thin CaF2(Eu) scintillator, a tapered fiber optics plate (tapered fiber), a position-sensitive photomultiplier tube (PSPMT) and a position calculation circuit. Though this configuration was originally planned as a high-resolution beta camera for direct measurement of positron distribution over brain surface of animals, we found that,

Seiichi Yamamoto; Takao Iida; Iwao Kanno

1997-01-01

209

AVHRR/1-FM Advanced Very High Resolution Radiometer  

NASA Technical Reports Server (NTRS)

The advanced very high resolution radiometer is discussed. The program covers design, construction, and test of a breadboard model, engineering model, protoflight model, mechanical/structural model, and a life test model. Special bench test and calibration equipment was developed for use on the program. The flight model program objectives were to fabricate, assemble and test four of the advanced very high resolution radiometers along with a bench cooler and collimator.

1979-01-01

210

Geiger-mode Avalanche Photodiodes for High Time Resolution Astrophysics  

Microsoft Academic Search

Geiger-mode Avalanche Photodiodes (GM-APDs) are establishing themselves as potential candidates for the broad temporal range\\u000a covered in high time resolution astrophysics (HTRA). These detectors have already been employed in astronomical instrumentation\\u000a and significant results have been obtained to date. Their high time resolution and quantum efficiency make these single photon\\u000a event counting detectors ideal for observations of stochastic phenomena, and

Don Phelan; Alan P. Morrison

2008-01-01

211

A high resolution SPECT detector based on thin continuous LYSO.  

PubMed

Single-photon emission computed tomography (SPECT) detectors with improved spatial resolution can be used to build multi-pinhole SPECT systems that have a higher sensitivity or a higher spatial resolution. In order to improve the spatial resolution we investigate the performance of a 2mm thick continuous Lutetium Yttrium Orthosilicate (LYSO) scintillator and compare it to the performance of a 5mm thick continuous NaI(Tl) scintillator. The advantages of LYSO are its high stopping power and its non-hygroscopicity. Drawbacksare the lower light output and the intrinsic radioactivity. The hypothesis of this study is that such a thin LYSO scintillator will have a small light spread and, as a consequence, will also have an improved spatial resolution when coupled to a Hamamatsu H8500 position sensitive photomultiplier tube. To optimize the spatial resolution and the useful detector area we used a mean nearest neighbor event-positioning method. Beam source measurements ((99m)Tc, 140keV) were done to investigate the energy resolution and the spatial resolution of both detectors. The effect of the intrinsic radioactivity of the LYSO scintillator in the energy window was quantified. The mean energy resolution is 9.3% for the NaI(Tl) scintillator and 21.3% for the LYSO scintillator. The LYSO spectrum shows an X-ray escape peak which decreases the detection efficiency with 9.1%. The spatial resolution of the LYSO detector (0.93mm full width at half maximum (FWHM)) is superior to the spatial resolution of the NaI(Tl) detector (1.37mm FWHM). The intrinsic radioactivity in the energy window (42% window centered at 140keV) is low (125.6 cps, 0.024 cps?mm(-3)). LYSO is a promising scintillator for small-animal SPECT imaging, where spatial resolution is more important than energy resolution. PMID:24334315

Deprez, Karel; Van Holen, Roel; Vandenberghe, Stefaan

2014-01-01

212

High-resolution noise radar using slow ADC  

NASA Astrophysics Data System (ADS)

Conventional digital signal processing scheme in noise radars has some limitations related to combination of high resolution and high dynamic range. Those limitations are caused by a tradeoff in performance of currently available ADCs: the faster is ADC the smaller is its depth (number of bits) available. Depth of the ADC determines relation between the smallest and highest observable signals and thus limits its dynamic range. In noise radar with conventional processing the sounding and reference signals are to be digitized at intermediate frequency band and to be processed digitally. The power spectrum bandwidth of noise signal which can be digitized with ADC depends on its sampling rate. The bandwidth of radar signal defines range resolution of any radar: the wider the spectrum the better the resolution. Actually this is the main bottleneck of high resolution Noise Radars: conventional processing doesn't enable to get both high range resolution and high dynamic range. In the paper we present a way to go around this drawback by changing signal processing ideology in noise radar. We present results of our consideration and design of high resolution Noise Radar which uses slow ADCs. The design is based upon generation of both probing and reference signals digitally and realization of their cross-correlation in an analog correlator. The output of the correlator is a narrowband signal that requires rather slow ADC to be sampled which nowadays may give up to 130 dB dynamic range.

Lukin, Konstantin; Vyplavin, Pavlo; Zemlyanyi, Oleg; Lukin, Sergiy; Palamarchuk, Volodymyr

2011-06-01

213

High-resolution Urban Image Classification Using Extended Features  

SciTech Connect

High-resolution image classification poses several challenges because the typical object size is much larger than the pixel resolution. Any given pixel (spectral features at that location) by itself is not a good indicator of the object it belongs to without looking at the broader spatial footprint. Therefore most modern machine learning approaches that are based on per-pixel spectral features are not very effective in high- resolution urban image classification. One way to overcome this problem is to extract features that exploit spatial contextual information. In this study, we evaluated several features in- cluding edge density, texture, and morphology. Several machine learning schemes were tested on the features extracted from a very high-resolution remote sensing image and results were presented.

Vatsavai, Raju [ORNL] [ORNL

2011-01-01

214

High resolution RGB color line scan camera  

NASA Astrophysics Data System (ADS)

A color line scan camera family which is available with either 6000, 8000 or 10000 pixels/color channel, utilizes off-the-shelf lenses, interfaces with currently available frame grabbers, includes on-board pixel by pixel offset correction, and is configurable and controllable via RS232 serial port for computer controlled or stand alone operation is described in this paper. This line scan camera is based on an available 8000 element monochrome line scan camera designed by AOA for OEM use. The new color version includes improvements such as better packaging and additional user features which make the camera easier to use. The heart of the camera is a tri-linear CCD sensor with on-chip color balancing for maximum accuracy and pinned photodiodes for low lag response. Each color channel is digitized to 12 bits and all three channels are multiplexed together so that the resulting camera output video is either a 12 or 8 bit data stream at a rate of up to 24Megpixels/sec. Conversion from 12 to 8 bit, or user-defined gamma, is accomplished by on board user-defined video look up tables. The camera has two user-selectable operating modes; lows speed, high sensitivity mode or high speed, reduced sensitivity mode. The intended uses of the camera include industrial inspection, digital archiving, document scanning, and graphic arts applications.

Lynch, Theodore E.; Huettig, Fred

1998-04-01

215

High resolution studies of deep earth structure  

NASA Astrophysics Data System (ADS)

Recent advances in seismic tomography has imaged major deep structure in the lower mantle. The ring of fast velocities originally derived from global long-period inversions has been resolved into interspersed sheet-like structure which appears to be old slabs. Beneath some of the structure, there are high velocity zones (HVZ) with variable thickness approaching the core mantle boundary (CMB). Seismic data recorded on TERRAscope and Berkeley Digital Seismic Network are used to study the HVZ beneath Central America. Modeling these waveforms (P, SV and SH) constitutes a major portion of this thesis. Two modeling strategies were employed in the thesis: (1) Assume a "Lay type" D ? with a sharp velocity discontinuity; (2) Assume an upper transition zone approaching D?, and a lower transition zone approaching the CMB (old slabs). Our preferred model following strategy (1) (Chapter 2) has an S discontinuity 200 km above the CMB with 3% jump and a negative gradient in the D? layer. In Chapter 4 the ULVZ beneath Iceland and Africa are addressed. The major phases used to study the ULVZ are SKS and SPdiffKS which travels along the CMB as P at both the core entry (SPdiffKS) and exit (SKPdiffS) locations. A major structure beneath Iceland (SKPdiffS) as identified from data recorded on stations in Northern Europe appears to be shaped like a dome, 80 km high, 200 km wide with a 10% drop in P and S velocities. The data for Africa is less complete but highly anomalous. Shear wave record sections across Africa and Europe containing the cross-over from S to SKS and extended core-phases (75 to 120) are presented from deep South American events. By studying the various branches of the core phases PKP, it has become quite clear that North-South paths in the inner-core appear faster than East-West paths Moreover, the broadband seismograms associated with these paths are distinct. The reason for this difference is not known but suggests a lower (anisotropic) inner-core with an upper (isotropic) inner-core which may have variable thickness. Modeling of long period and broadband data for such structures is, also, addressed in Chapter 5 of this thesis. (Abstract shortened by UMI.)

Ding, Xiaoming

1998-11-01

216

High Resolution Recombination Measurements of Stored Ions  

SciTech Connect

The accuracy obtained in electron-ion recombination experiments at storage rings has reached a level which allows strenuous tests of theoretical models and the ability to derive accurate, and useful, information for applications such as plasma modeling and diagnostics. Here we present two such recombination experiments performed at the heavy ion storage ring CRYRING. First, we investigated the possibility to derive a temperature dependent plasma rate coefficient for Na-like Ni, which has been observed in emission lines from active solar regions and laboratory plasmas. Second, we determined the 2s1/2-2p1/2 energy splitting in Li-like Kr. Such a highly charged ion exhibits large QED contributions ({approx}1.5 eV) which are difficult to represent in theoretically calculations. The experimental value for the splitting was determined to within 8 meV while the theoretically determined value is only accurate to within 19 meV.

Fogle, M.; Ekloew, N.; Lindroth, E.; Madzunkov, S.; Mohamed, T.; Schuch, R.; Tokman, M. [Department of Atomic Physics, Stockholm University, Alba Nova (SCFAB), SE106 91 Stockholm (Sweden); Badnell, N. [Department of Physics and Applied Physics, University of Strathclyde, G4 0NG Glasglow (United Kingdom)

2003-08-26

217

High-resolution gravity model of Venus  

NASA Technical Reports Server (NTRS)

The anomalous gravity field of Venus shows high correlation with surface features revealed by radar. We extract gravity models from the Doppler tracking data from the Pioneer Venus Orbiter by means of a two-step process. In the first step, we solve the nonlinear spacecraft state estimation problem using a Kalman filter-smoother. The Kalman filter has been evaluated through simulations. This evaluation and some unusual features of the filter are discussed. In the second step, we perform a geophysical inversion using a linear Bayesian estimator. To allow an unbiased comparison between gravity and topography, we use a simulation technique to smooth and distort the radar topographic data so as to yield maps having the same characteristics as our gravity maps. The maps presented cover 2/3 of the surface of Venus and display the strong topography-gravity correlation previously reported. The topography-gravity scatter plots show two distinct trends.

Reasenberg, R. D.; Goldberg, Z. M.

1992-01-01

218

Quantifying and containing the curse of high resolution coronal imaging  

E-print Network

Future missions such as Solar Orbiter (SO), InterHelioprobe, or Solar Probe aim at approaching the Sun closer than ever before, with on board some high resolution imagers (HRI) having a subsecond cadence and a pixel area of about $(80km)^2$ at the Sun during perihelion. In order to guarantee their scientific success, it is necessary to evaluate if the photon counts available at these resolution and cadence will provide a sufficient signal-to-noise ratio (SNR). We perform a first step in this direction by analyzing and characterizing the spatial intermittency of Quiet Sun images thanks to a multifractal analysis. We identify the parameters that specify the scale-invariance behavior. This identification allows next to select a family of multifractal processes, namely the Compound Poisson Cascades, that can synthesize artificial images having some of the scale-invariance properties observed on the recorded images. The prevalence of self-similarity in Quiet Sun coronal images makes it relevant to study the ratio between the SNR present at SoHO/EIT images and in coarsened images. SoHO/EIT images thus play the role of 'high resolution' images, whereas the 'low-resolution' coarsened images are rebinned so as to simulate a smaller angular resolution and/or a larger distance to the Sun. For a fixed difference in angular resolution and in Spacecraft-Sun distance, we determine the proportion of pixels having a SNR preserved at high resolution given a particular increase in effective area. If scale-invariance continues to prevail at smaller scales, the conclusion reached with SoHO/EIT images can be transposed to the situation where the resolution is increased from SoHO/EIT to SO/HRI resolution at perihelion.

Vronique Delouille; Pierre Chainais; Jean-Franois Hochedez

2008-08-22

219

High-resolution climate simulation of the last glacial maximum  

SciTech Connect

The climate of the last glacial maximum (LGM) is simulated with a high-resolution atmospheric general circulation model, the NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. The purpose of the study is to assess whether there are significant benefits from the higher resolution simulation compared to the lower resolution simulation associated with the role of topography. The LGM simulations were forced with modified CLIMAP sea ice distribution and sea surface temperatures (SST) reduced by 1 C, ice sheet topography, reduced CO{sub 2}, and 21,000 BP orbital parameters. The high-resolution model captures modern climate reasonably well, in particular the distribution of heavy precipitation in the tropical Pacific. For the ice age case, surface temperature simulated by the high-resolution model agrees better with those of proxy estimates than does the low-resolution model. Despite the fact that tropical SSTs were only 2.1 C less than the control run, there are many lowland tropical land areas 4-6 C colder than present. Comparison of T170 model results with the best constrained proxy temperature estimates (noble gas concentrations in groundwater) now yield no significant differences between model and observations. There are also significant upland temperature changes in the best resolved tropical mountain belt (the Andes). We provisionally attribute this result in part as resulting from decreased lateral mixing between ocean and land in a model with more model grid cells. A longstanding model-data discrepancy therefore appears to be resolved without invoking any unusual model physics. The response of the Asian summer monsoon can also be more clearly linked to local geography in the high-resolution model than in the low-resolution model; this distinction should enable more confident validation of climate proxy data with the high-resolution model. Elsewhere, an inferred salinity increase in the subtropical North Atlantic may have significant implications for ocean circulation changes during the LGM. A large part of the Amazon and Congo Basins are simulated to be substantially drier in the ice age - consistent with many (but not all) paleo data. These results suggest that there are considerable benefits derived from high-resolution model regarding regional climate responses, and that observationalists can now compare their results with models that resolve geography at a resolution comparable to that which the proxy data represent.

Erickson III, David J [ORNL

2008-01-01

220

High-resolution climate simulation of the last glacial maximum  

NASA Astrophysics Data System (ADS)

The climate of the last glacial maximum (LGM) is simulated with a high-resolution atmospheric general circulation model, the NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. The purpose of the study is to assess whether there are significant benefits from the higher resolution simulation compared to the lower resolution simulation associated with the role of topography. The LGM simulations were forced with modified CLIMAP sea ice distribution and sea surface temperatures (SST) reduced by 1C, ice sheet topography, reduced CO2, and 21,000 BP orbital parameters. The high-resolution model captures modern climate reasonably well, in particular the distribution of heavy precipitation in the tropical Pacific. For the ice age case, surface temperature simulated by the high-resolution model agrees better with those of proxy estimates than does the low-resolution model. Despite the fact that tropical SSTs were only 2.1C less than the control run, there are many lowland tropical land areas 4 6C colder than present. Comparison of T170 model results with the best constrained proxy temperature estimates (noble gas concentrations in groundwater) now yield no significant differences between model and observations. There are also significant upland temperature changes in the best resolved tropical mountain belt (the Andes). We provisionally attribute this result in part as resulting from decreased lateral mixing between ocean and land in a model with more model grid cells. A longstanding model-data discrepancy therefore appears to be resolved without invoking any unusual model physics. The response of the Asian summer monsoon can also be more clearly linked to local geography in the high-resolution model than in the low-resolution model; this distinction should enable more confident validation of climate proxy data with the high-resolution model. Elsewhere, an inferred salinity increase in the subtropical North Atlantic may have significant implications for ocean circulation changes during the LGM. A large part of the Amazon and Congo Basins are simulated to be substantially drier in the ice ageconsistent with many (but not all) paleo data. These results suggest that there are considerable benefits derived from high-resolution model regarding regional climate responses, and that observationalists can now compare their results with models that resolve geography at a resolution comparable to that which the proxy data represent.

Kim, Seong-Joong; Crowley, Thomas J.; Erickson, David J.; Govindasamy, Bala; Duffy, Phillip B.; Lee, Bang Yong

2008-07-01

221

High-resolution quantitative imaging of mammalian and bacterial cells using stable isotope mass spectrometry  

PubMed Central

Background Secondary-ion mass spectrometry (SIMS) is an important tool for investigating isotopic composition in the chemical and materials sciences, but its use in biology has been limited by technical considerations. Multi-isotope imaging mass spectrometry (MIMS), which combines a new generation of SIMS instrument with sophisticated ion optics, labeling with stable isotopes, and quantitative image-analysis software, was developed to study biological materials. Results The new instrument allows the production of mass images of high lateral resolution (down to 33 nm), as well as the counting or imaging of several isotopes simultaneously. As MIMS can distinguish between ions of very similar mass, such as 12C15N- and 13C14N-, it enables the precise and reproducible measurement of isotope ratios, and thus of the levels of enrichment in specific isotopic labels, within volumes of less than a cubic micrometer. The sensitivity of MIMS is at least 1,000 times that of 14C autoradiography. The depth resolution can be smaller than 1 nm because only a few atomic layers are needed to create an atomic mass image. We illustrate the use of MIMS to image unlabeled mammalian cultured cells and tissue sections; to analyze fatty-acid transport in adipocyte lipid droplets using 13C-oleic acid; to examine nitrogen fixation in bacteria using 15N gaseous nitrogen; to measure levels of protein renewal in the cochlea and in post-ischemic kidney cells using 15N-leucine; to study DNA and RNA co-distribution and uridine incorporation in the nucleolus using 15N-uridine and 81Br of bromodeoxyuridine or 14C-thymidine; to reveal domains in cultured endothelial cells using the native isotopes 12C, 16O, 14N and 31P; and to track a few 15N-labeled donor spleen cells in the lymph nodes of the host mouse. Conclusion MIMS makes it possible for the first time to both image and quantify molecules labeled with stable or radioactive isotopes within subcellular compartments. PMID:17010211

Lechene, Claude; Hillion, Francois; McMahon, Greg; Benson, Douglas; Kleinfeld, Alan M; Kampf, J Patrick; Distel, Daniel; Luyten, Yvette; Bonventre, Joseph; Hentschel, Dirk; Park, Kwon Moo; Ito, Susumu; Schwartz, Martin; Benichou, Gilles; Slodzian, Georges

2006-01-01

222

High-resolution Real-Time Radiography (RTR) system design  

NASA Astrophysics Data System (ADS)

A high-resolution real-time radiography (RTR) system was designed for aerospace component X-ray inspections in the 20 to 300 kV range. Particulate and glass X-ray converters, image intensifiers, and video camera components were performance tested for resolution greater than 10 lp/mm, dynamic range greater than 1000, contrast sensitivity of 1 percent, and image size of 12 x12 in. A breadboard RTR system, constructed with optimized components, produced 1024 x 1024 pixels per image with 8 bits per pixel. Computer controlled optical zooming achieved horizontal fields of view from 12.8 to 0.5 in. and corresponding resolutions of 3 to 80 pixels mm. Conceptual high-resolution RTR prototype systems were designed using the test results.

Klynn, L. M.; Barry, R. C.; Barker, M. D.; Bueno, C.; Maple, T. G.

1987-07-01

223

Performance of a High Resolution Cavity Beam Position Monitor System  

SciTech Connect

It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

2006-12-18

224

High-spectral-resolution multiplex CARS spectroscopy using chirped pulses  

NASA Astrophysics Data System (ADS)

A novel technique for achieving high spectral resolution with a femtosecond laser system is presented. Transform-limited 800 nm, 90 femtosecond (fs) pulses pass off two gratings, stretching the pulse in time to a pulse width of several picoseconds due to an induced linear temporal chirp directly proportional to the grating separation. This chirped pulse is the degenerate pump (?P) and probe (?p) pulse for the CARS experiment. When overlapped in time with the 1050 nm, 90 fs transform-limited Stokes (?S) pulse, only a fraction of the chirped ?p pulse generates the CARS signal, thereby creating a temporal slit that defines the spectral resolution of the technique. Spectra for liquid methanol and liquid isooctane are presented, with ~6 cm-1 spectral resolution achieved for isooctane. Resonance enhancement and the mechanism of achieving high spectral resolution are shown by adjusting the ?S wavelength and ?p delay relative to the ?S pulse.

Knutsen, Kelly P.; Johnson, Justin C.; Miller, Abigail E.; Petersen, Poul B.; Saykally, Richard J.

2004-06-01

225

A Pipeline for High Resolution Radio Images  

NASA Astrophysics Data System (ADS)

The VLBA Calibrator Survey (VCS) is a database of ~2200 extragalactic radio sources evenly distributed on the sky between declinations of -40 and +90 degrees. In addition to providing a list of potential phase and bandpass calibrators for science observations, the very high astrometric accuracy of the VCS has also proven enormously useful in establishing and refining the International Celestial Reference Frame (ICRF). Using the VLBA at 2.3 and 8.4 GHz, we have recently begun a new epoch of snapshot observations of ~2400 compact VCS sources. Here, we present the preliminary results of a project, conducted with the Common Astronomy Software Applications package (CASA), to design and implement an imaging pipeline for these observations . This pipeline provides images of the sources that are useful for determining their quality as VLBA calibrators and for potentially revealing details that might make them scientifically interesting in their own right. As the observations of this survey are still in progress, we present preliminary images of a few of the sources that have been observed thus far. When completed, these observations will allow significant improvements in the next generation ICRF.

Thomas, Brianna P.; Peck, Alison B.; Hodge, Jacqueline; Beasley, Anthony J.; VCS Team

2015-01-01

226

High spectral resolution image of Barnacle Bill  

NASA Technical Reports Server (NTRS)

The rover Sojourner's first target for measurement by the Alpha-Proton-Xray Spectrometer (APXS) was the rock named Barnacle Bill, located close to the ramp down which the rover made its egress from the lander. The full spectral capability of the Imager for Mars Pathfinder (IMP), consisting of 13 wavelength filters, was used to characterize the rock's surface. The measured area is relatively dark, and is shown in blue. Nearby on the rock surface, soil material is trapped in pits (shown in red).

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

1997-01-01

227

High-resolution numerical simulations for galaxy formation  

E-print Network

Understanding of the structure evolution in the Universe has been greatly advanced with a rapid progress in high-resolution cosmological simulations. In this contribution, we report a new set of cosmological simulations with $512^3$ ($\\sim 1.4\\times 10^8$) particles in a simulation box of $100\\mpc$. With this unprecedented resolution, we have successfully overcomed the over-merging problem while retaining a cosmological volume size that is crucial for the statistical analysis. The simulations are being applied to studying important astrophysical problems that are sensitive to the simulation resolution.

Y. P. Jing; Yasushi Suto

2002-01-10

228

High spectral resolution multiplex CARS spectroscopy using chirped pulses  

NASA Astrophysics Data System (ADS)

A simple technique for achieving high spectral resolution coherent anti-Stokes Raman scattering (CARS) spectra with a femtosecond laser system is presented. A linearly chirped and stretched (10 ps) pump pulse generates CARS signal only when overlapped in time with the Stokes pulse (90 fs), creating a `temporal slit' that defines the spectral resolution of the technique. Multiplex CARS spectra for liquid methanol and liquid isooctane are presented, demonstrating a spectral resolution of better than 5 cm -1. This new chirped (c-CARS) technique should prove useful for chemically-selective imaging applications, as it significantly reduces the non-resonant background contribution.

Knutsen, K. P.; Johnson, J. C.; Miller, A. E.; Petersen, P. B.; Saykally, R. J.

2004-04-01

229

Statistical properties of multifrequency high-range-resolution sea reflections  

Microsoft Academic Search

The statistical properties of multifrequency high-range-resolution, low-grazing-angle measurements of sea clutter are presented. It is shown that the compound form of the K-distribution provides an excellent description for measurements made at S, X and J bands for all the radar range resolutions employed (0.375 m to 15 m). It is also shown that the K-distribution shape parameter tends to decrease

T. Hair; T. Lee; C. J. Baker

1991-01-01

230

The Suzaku High Resolution X-Ray Spectrometer  

Microsoft Academic Search

The X-Ray Spectrometer (XRS) has been designed to provide the Suzaku Observatory with non-dispersive, high-resolution X-ray spectroscopy. As designed, the instrument covers the energy range 0.3 to 12keV, which encompasses the most diagnostically rich part of the X-ray band. The sensor consists of a 32-channel array of X-ray microcalorimeters, each with an energy resolution of about 6eV. The very low

Richard L. Kelley; Kazuhisa Mitsuda; Christine A. Allen; Petar Arsenovic; Michael D. Audley; Thomas G. Bialas; Kevin R. Boyce; Robert F. Boyle; Susan R. Breon; Gregory V. Brown; Jean Cottam; Michael J. Dipirro; Ryuichi Fujimoto; Tae Furusho; Keith C. Gendreau; Gene G. Gochar; Oscar Gonzalez; Masayuki Hirabayashi; Stephen S. Holt; Hajime Inoue; Manabu Ishida; Yoshitaka Ishisaki; Carol S. Jones; Ritva Keski-Kuha; Caroline A. Kilbourne; Dan McCammon; Umeyo Morita; S. Harvey Moseley; Brent Mott; Katsuhiro Narasaki; Yoshiaki Ogawara; Takaya Ohashi; Naomi Ota; John S. Panek; F. Scott Porter; Aristides Serlemitsos; Peter J. Shirron; Gary A. Sneiderman; Andrew E. Szymkowiak; Yoh Takei; June L. Tveekrem; Stephen M. Volz; Mikio Yamamoto; Noriko Y. Yamasaki

2007-01-01

231

High-resolution optical imaging of magnetic-domain structures  

Microsoft Academic Search

High-resolution optical techniques for imaging magnetic domains in ferromagnetic materials such as confocal microscopy and scanning near-field optical microscopy (SNOM) are reviewed. The imaging capabilities of different techniques and image formation are discussed in the case of in-plane as well as out-of-plane magnetic anisotropy in different illumination configurations. It is shown that the magnetooptical resolution of near-field measurements depends on

Wayne Dickson; Satoshi Takahashi; Robert Pollard; Ron Atkinson; Anatoly V. Zayats

2005-01-01

232

An all-fiber high resolution fiber grating concentration sensor  

Microsoft Academic Search

An all-fiber high resolution optical fiber grating concentration sensor has been studied theoretically and experimentally. A long period grating is used as the sensor head and a wavelength matched fiber Bragg grating is used as an interrogator to convert wavelength into intensity encoded information for interrogation. A concentration resolution of 0.104g\\/L for NaCl solution is realized in experiment. The all-fiber

Yage Zhan; Jun Luo; Hua Wu; Muhuo Yu

233

High-resolution global upper mantle structure and plate tectonics  

Microsoft Academic Search

A global high-resolution S wave velocity model RG5.5 is obtained for the upper 500 km of Earth's mantle using a 5 x 5 deg equal-area block parameterization. The data set consists of some 18,000 seismograms associated with 971 events with magnitudes larger than 5.5. Fundamental modes are used with periods from 75 to 250 s. The horizontal resolution length is

Yu-Shen Zhang; Toshiro Tanimoto

1993-01-01

234

A microfluidic high-resolution NMR flow probe.  

PubMed

A microfluidic high-resolution NMR flow probe based on a novel stripline detector chip is demonstrated. This tool is invaluable for the in situ monitoring of reactions performed in microreactors. As an example, the acetylation of benzyl alcohol with acetyl chloride was monitored. Because of the uncompromised (sub-Hz) resolution, this probe holds great promise for metabolomics studies, as shown by an analysis of 600 nL of human cerebrospinal fluid. PMID:19320484

Bart, Jacob; Kolkman, Ard J; Oosthoek-de Vries, Anna Jo; Koch, Kaspar; Nieuwland, Pieter J; Janssen, Hans J W G; van Bentum, Jan P J M; Ampt, Kirsten A M; Rutjes, Floris P J T; Wijmenga, Sybren S; Gardeniers, Han J G E; Kentgens, Arno P M

2009-04-15

235

Infrared emission high spectral resolution atlas of the stratospheric limb  

SciTech Connect

An atlas of high resolution infrared emission spectra identifies a number of gaseous atmospheric features significant to stratospheric chemistry in the 770--900- and 1100--1360-cm/sup -1/ regions at six zenith angles from 86.7 to 95.1/sup 0/. A balloon-borne Michelson interferometer was flown to obtain /similar to/0.03-cm/sup -1/ resolution spectra. Two 10-cm/sup -1/ extracts are presented here.

Maquire, W.C.; Kunde, V.G.; Herath, L.W.

1989-03-15

236

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

PubMed

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 1.2נ1.2mm(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 (?) 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 2mm in nearly all positions within the FOV without resolution recovery, reaching around 2.5mm in some locations, they fell below 1.8mm 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. PMID:24986422

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

2014-11-01

237

Isotope specific resolution recovery image reconstruction in high resolution PET imaging  

SciTech Connect

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 recovery image reconstruction. The benefits are expected to be more substantial for more energetic positron emitting isotopes such as Oxygen-15 and Rubidium-82.

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)] [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)] [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)] [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)] [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) [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

238

High resolution photolithography with sub-wavelength grating  

NASA Astrophysics Data System (ADS)

Based on the theory of surface plasmon resonance and the special nano-optical effect of metal/dielectric multilayer composites, we obtained a high-resolution image of a sub-wavelength grating. We discussed multilayer parameters on equal thickness, and achieved sufficient contrast and high intensity through numerical simulation based on the finite element method. By chosen the best scheme, an experimental of multilayer planar lens lithography has been carried out. The main point is the use of metal-dielectric composites to realize high-resolution image under 365-nm polarization light incidence. By controlling the experimental parameters accurately, a fidelity image is recorded on the photoresist.

Zhao, Qing; Liang, Gaofeng; Wang, Changtao; Huang, Xiaoping; Chen, Zexiang; Luo, Xiangang

2014-04-01

239

High resolution BPMS with integrated gain correction system  

SciTech Connect

High resolution beam position monitors (BPM) are an essential tool to achieve and reproduce a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring. The ATF damping ring (DR) BPMs are currently upgraded with new high resolution read-out electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducible beam position readings. The concept and its technical realization, as well as preliminary results of beam studies are presented.

Wendt, M.; Briegel, C.; Eddy, N.; Fellenz, B.; Gianfelice, E.; Prieto, P.; Rechenmacher, R.; Voy, D.; /Fermilab; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba

2009-08-01

240

High-resolution land cover classification using low resolution global data  

NASA Astrophysics Data System (ADS)

A fusion approach is described that combines texture features from high-resolution panchromatic imagery with land cover statistics derived from co-registered low-resolution global databases to obtain high-resolution land cover maps. The method does not require training data or any human intervention. We use an MxN Gabor filter bank consisting of M=16 oriented bandpass filters (0-180) at N resolutions (3-24 meters/pixel). The size range of these spatial filters is consistent with the typical scale of manmade objects and patterns of cultural activity in imagery. Clustering reduces the complexity of the data by combining pixels that have similar texture into clusters (regions). Texture classification assigns a vector of class likelihoods to each cluster based on its textural properties. Classification is unsupervised and accomplished using a bank of texture anomaly detectors. Class likelihoods are modulated by land cover statistics derived from lower resolution global data over the scene. Preliminary results from a number of Quickbird scenes show our approach is able to classify general land cover features such as roads, built up area, forests, open areas, and bodies of water over a wide range of scenes.

Carlotto, Mark J.

2013-05-01

241

Evacuee Compliance Behavior Analysis using High Resolution Demographic Information  

SciTech Connect

The purpose of this study is to examine whether evacuee compliance behavior with route assignments from different resolutions of demographic data would impact the evacuation performance. Most existing evacuation strategies assume that travelers will follow evacuation instructions, while in reality a certain percent of evacuees do not comply with prescribed instructions. In this paper, a comparison study of evacuation assignment based on Traffic Analysis Zones (TAZ) and high resolution LandScan USA Population Cells (LPC) were conducted for the detailed road network representing Alexandria, Virginia. A revised platform for evacuation modeling built on high resolution demographic data and activity-based microscopic traffic simulation is proposed. The results indicate that evacuee compliance behavior affects evacuation efficiency with traditional TAZ assignment, but it does not significantly compromise the efficiency with high resolution LPC assignment. The TAZ assignment also underestimates the real travel time during evacuation, especially for high compliance simulations. This suggests that conventional evacuation studies based on TAZ assignment might not be effective at providing efficient guidance to evacuees. From the high resolution data perspective, traveler compliance behavior is an important factor but it does not impact the system performance significantly. The highlight of evacuee compliance behavior analysis should be emphasized on individual evacuee level route/shelter assignments, rather than the whole system performance.

Lu, Wei [ORNL] [ORNL; Han, Lee [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Liu, Cheng [ORNL] [ORNL; Tuttle, Mark A [ORNL] [ORNL; Bhaduri, Budhendra L [ORNL] [ORNL

2014-01-01

242

[Pulmonary lesion of paraquat poisoning on high resolution CT].  

PubMed

It is well known that paraquat causes severe organ-toxicity and pulmonary damage. We observed the progress of a patient who survived paraquat poisoning, and we recorded the changes in the lung by high resolution CT. The patient was a 35-year-old man who attempted suicide by paraquat (Guramoxone 100 ml) ingestion. At the time of hospitalization, there was no respiratory involvement. Five days after ingestion, an X-ray examination showed only indistinct vascularity of both lung fields, but high resolution CT showed increased density in the central part of both lung fields. According to the clinical progress after ingestion, mediastinal and subcutaneous emphysema were noted by chest X-ray examination. On the other hand, severe interstitial pneumonia progression of severe lung fibrosis with a decrease in lung volume and interstitial pulmonary emphysema in addition to mediastinal, subcutaneous emphysema were seen by high resolution CT. High resolution CT is useful for detecting morphologic change and diagnosing clinical stages. Observing the course of changes by high resolution CT is useful for deciding the course of clinical therapy, and we have no hesitation in affirming that it should be used in such cases. PMID:2330462

Kageyama, J; Satoh, K; Kawase, Y; Kojima, K; Tamai, T; Ohkawa, M; Tanabe, M; Shirakawa, Y; Oguri, K

1990-03-01

243

Studying Thermoelectric Oxides using High-Resolution Scanning Transmission Electron Figure 4: a) Atomic resolution Z-  

E-print Network

Studying Thermoelectric Oxides using High-Resolution Scanning Transmission Electron Microscopy 0 the environmental impact, and deliver energy continuously, such as thermo-electric power generation, have often been overlooked. Thermo-electric (TE) power applications offer a potentially cheap, pollution- and maintenance

Ben-Arie, Jezekiel

244

High-resolution and broadband all-fiber spectrometers  

E-print Network

High-resolution and broadband all-fiber spectrometers BRANDON REDDING,1 MANSOOR ALAM,2 MARTIN transmission with minimal loss. In turn, the ubiquity of high-quality, low-cost fibers has enabled a number of additional applications, including fiber sensors, fiber lasers, and imaging fiber bundles. Recently, we

Cao, Hui

245

High resolution underwater fiber optic threat detection system  

Microsoft Academic Search

Current underwater protection systems are complex expensive devices consisting of multiple electronic sensing elements. The detection and identification of divers and small submerged watercraft requires very high image resolution. The high price of an array of conventional piezoelectric transducers and associated electronic components makes this solution feasible for localized implementations, but the protection of large stretches of coastline requires a

Alexander Berger; Shalmon Hermesh; Eugene Durets; Lothar U. Kempen

2006-01-01

246

Development of high resolution TDC ASICs at GSI  

Microsoft Academic Search

Based on the long experience on high precision time measurement systems at GSI the GSI ASIC design group is developing a new TDC ASIC for CBM one of the next generation large scale experiments at GSI. The main requirement on the TDC is the high timing resolution < 20 ps. The data acquisition architecture has to be event driven. Two

Holger Flemming; Harald Deppe

2007-01-01

247

A high resolution computed tomographic system for industrial applications  

Microsoft Academic Search

This paper describes the development of a high-resolution computed tomography system designed especially for industrial examinations. This system has been used to examine aircraft engine turbine blades for dimensional accuracy, high-performance ceramics for density distributions and defects, and components from the automotive industry. Results of these measurements are presented.

W. Nuding; R. Grimm; R. Link; H. Wiacker; John J. Munro III

1989-01-01

248

Infrared spectroscopic imaging with high spatial resolution and high sensitivity  

Microsoft Academic Search

Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) is a very sensitive imaging technique for the characterization of molecular films. In order to achieve a spatial resolution close to the diffraction limit a very small pinhole which acts as a point-source has to be used. However, such a small pinhole, the typical diameter would be app. 100 mum, may reduces dramatically

Valdas Sablinskas; Gerald Steiner; Justinas Ceponkus; Reiner Salzer

2008-01-01

249

Lynx: A High-Resolution Synthetic Aperture Radar  

SciTech Connect

Lynx is a high resolution, synthetic aperture radar (SAR) that has been designed and built by Sandia National Laboratories in collaboration with General Atomics (GA). Although Lynx may be operated on a wide variety of manned and unmanned platforms, it is primarily intended to be fielded on unmanned aerial vehicles. In particular, it may be operated on the Predator, I-GNAT, or Prowler II platforms manufactured by GA Aeronautical Systems, Inc. The Lynx production weight is less than 120 lb. and has a slant range of 30 km (in 4 mm/hr rain). It has operator selectable resolution and is capable of 0.1 m resolution in spotlight mode and 0.3 m resolution in stripmap mode. In ground moving target indicator mode, the minimum detectable velocity is 6 knots with a minimum target cross-section of 10 dBsm. In coherent change detection mode, Lynx makes registered, complex image comparisons either of 0.1 m resolution (minimum) spotlight images or of 0.3 m resolution (minimum) strip images. The Lynx user interface features a view manager that allows it to pan and zoom like a video camera. Lynx was developed under corporate finding from GA and will be manufactured by GA for both military and commercial applications. The Lynx system architecture will be presented and some of its unique features will be described. Imagery at the finest resolutions in both spotlight and strip modes have been obtained and will also be presented.

Doerry, A.W.; Hensley, W.H.; Pace, F.; Stence, J.; Tsunoda, S.I.; Walker, B.C.; Woodring, M.

1999-03-08

250

High-resolution Climate Simulation of the Last Glacial Maximum  

NASA Astrophysics Data System (ADS)

The climate of the last glacial maximum (LGM) is simulated with a high-resolution atmospheric general circulation model of NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. LGM simulations were forced with the reconstructed CLIMAP sea surface temperatures and sea ice distribution, ice sheet topography, reduced CO2, and orbital parameters. The high-resolution model captures modern climate reasonably well, in particular the distribution of heavy precipitation in the tropical Pacific. The response of the Asian summer monsoon is larger in the high-resolution model than in the low-resolution version of the model associated with a larger thermal response due to a better representation of topography of the Tibetan Plateau. The westerly jet splitting around the Laurentide ice sheet persists with the lower elevated ice sheet. In the LGM simulation, the western part of U.S. is wetter in consistent with proxy evidence. The eastern rim of U.S. is also wetter, especially in winter. While the Amazon is simulated to be drier in the LGM, the western and central South America appears to be wetter, as is the eastern Africa. A dramatic cooling is simulated in the northern North Atlantic and northern Europe due to the presence of ice sheet and the extension of sea ice. Overall, the high-resolution model capture detailed regional climate features over lands and its simulations are in a broad agreement with observational proxy evidence.

Kim, S.; Crowley, T. J.; Erickson, D. J.; Givindasamy, B.; Duffy, P.; Lee, B.

2006-12-01

251

High spectral resolution measurements for the ARM Program  

SciTech Connect

This report focuses on the design and fabrication of high spectral resolution FTIR (Fourier Transform Infrared) instrumentation for the CART sites of the Atmospheric Radiation Measurement (ARM) Program. The ultimate objective of this grant is to develop three different types of instruments, named the AERI, AERI-X, and SORT. The Atmospheric Emitted Radiance Interferometer (AERI) is the simplest. It will be available for early deployment at the first ARM site and will be deployable at several locations in the extended network to give horizontal coverage. The AERI will be an 0.5 cm{sup {minus}1} resolution instrument, which measures accurately calibrated radiance spectra for radiation studies and for remote sensing of atmospheric state variables. The AERI-X and the SORTI are higher spectral resolution instruments for obtaining the highest practical resolution for spectroscopy at the ARM central sites. The AERI-X, like the AERI will measure atmospheric emitted radiance, but with resolutions as high as 0.1 cm{sup {minus}1}. The Solar Radiance Transmission Interferometer will measure the total transmission of the atmosphere by tracking the sun through changes in atmospheric air mass. The large solar signal makes it practical for this instrument to offer the ultimate in spectral resolution, about 0.002 cm{sup {minus}1}.

Revercomb, H.E.

1992-05-22

252

High-resolution adaptive optics test bed for vision science  

NASA Astrophysics Data System (ADS)

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.

Wilks, Scott C.; Thompson, Charles A.; Olivier, Scot S.; Bauman, Brian J.; Flath, Laurence M.; Silva, Dennis A.; Sawvel, Robert M.; Barnes, Thomas B.; Werner, John S.

2002-02-01

253

High-resolution structure of viruses from random diffraction snapshots  

E-print Network

The advent of the X-ray Free Electron Laser (XFEL) has made it possible to record diffraction snapshots of biological entities injected into the X-ray beam before the onset of radiation damage. Algorithmic means must then be used to determine the snapshot orientations and thence the three-dimensional structure of the object. Existing Bayesian approaches are limited in reconstruction resolution typically to 1/10 of the object diameter, with the computational expense increasing as the eighth power of the ratio of diameter to resolution. We present an approach capable of exploiting object symmetries to recover three-dimensional structure to high resolution, and thus reconstruct the structure of the satellite tobacco necrosis virus to atomic level. Our approach offers the highest reconstruction resolution for XFEL snapshots to date, and provides a potentially powerful alternative route for analysis of data from crystalline and nanocrystalline objects.

Hosseinizadeh, A; Dashti, A; Fung, R; D'Souza, R M; Ourmazd, A

2014-01-01

254

Investigating the uncertainty in multi-fiber estimation in High Angular Resolution Diffusion Imaging  

E-print Network

-values. Keywords: High Angular Resolution Diffusion Imaging, Tensor Distribution Function, multi-fiberInvestigating the uncertainty in multi-fiber estimation in High Angular Resolution Diffusion between scanning time and angular precision in High Angular Resolution Diffusion Imaging (HARDI

Thompson, Paul

255

HRSC: the High Resolution Stereo Camera of Mars Express  

NASA Astrophysics Data System (ADS)

The High Resolution Stereo Camera (HRSC), originally developed for the Russian-led Mars-96 mission, was selected as part of the Orbiter payload for ESA's Mars Express mission. The HRSC is a pushbroom scanning instrument with nine CCD line detectors mounted in parallel in the focal plane. Its unique feature is the ability to obtain near-simultaneous imaging data of a specific site at high resolution, with along-track triple stereo, four colours and five different phase angles, thus avoiding any time-dependent variations of the observational conditions. An additional Super-Resolution Channel (SRC) - a framing device - will yield nested images in the metre-resolution range for detailed photogeologic studies. The spatial resolution from the nominal periapsis altitude of 250 km will be 10 m px-1, with an image swath of 53 km, for the HRSC and 2.3 m px-1 for the SRC. During the mission's nominal operational lifetime of 1 martian year (2 Earth years) and assuming an average HRSC data transfer share of 40%, it will be possible to cover at least 50% of the martian surface at a spatial resolution of ?15 m px-1. More than 70% of the surface can be observed at a spatial resolution of ?30 m px-1, while more than 1% will be imaged at better than 2.5 m px-1. The HRSC will thus close the gap between the medium- to low-resolution coverage and the very high-resolution images of the Mars Observer Camera on the Mars Global Surveyor mission and the in situ observations and measurements by landers. The HRSC will make a major contribution to the study of martian geosciences, with special emphasis on the evolution of the surface in general, the evolution of volcanism, and the role of water throughout martian history. The instrument will obtain images containing morphologic and topographic information at high spatial and vertical resolution, allowing the improvement of the cartographic base down to scales of 1:50000. The experiment will also address atmospheric phenomena and atmosphere-surface interactions, and will provide urgently needed support for current and furture lander missions as well as for exobiological studies. The goals of HRSC on Mars Express will not be met by any other planned mission or instrument.

Neukum, G.; Jaumann, R.

2004-08-01

256

High-Resolution and Microscopic Imaging at High Field  

Microsoft Academic Search

The goal of improved spatial resolution in magnetic resonance imaging for better visualization of finer and finer structural\\u000a details in the body is driven by a long tradition of microscopy in conventional anatomy. Centuries of anatomical studies have\\u000a underscored the success with which the study of function and dysfunction can be complemented by the study of normal and pathological\\u000a structure.

Lawrence L. Wald; Bruce Fischl; Bruce R. Rosen

257

High resolution single-shot EPI at 7T  

Microsoft Academic Search

ObjectiveSingle-shot echo planar imaging (EPI) acquisitions at 7T are challenging due to increased distortions, signal dropouts, RF-power\\u000a requirements, and reduced T2*. This study developed and tested pulse sequence and protocol modifications required to allow\\u000a high resolution EPI for whole brain functional neuroimaging.\\u000a \\u000a \\u000a \\u000a Materials and methodsUsing geometric distortion correction methods, modified fat saturation, and parallel imaging, we acquired high resolution\\u000a single-shot

Oliver Speck; J. Stadler; M. Zaitsev

2008-01-01

258

High-resolution low-dose scanning transmission electron microscopy  

PubMed Central

During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM. PMID:19915208

Buban, James P.; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D.; Stahlberg, Henning

2010-01-01

259

HIRES: the high resolution spectrograph for the E-ELT  

NASA Astrophysics Data System (ADS)

The current instrumentation plan for the E-ELT foresees a High Resolution Spectrograph conventionally indicated as HIRES. Shaped on the study of extra-solar planet atmospheres, Pop-III stars and fundamental physical constants, HIRES is intended to embed observing modes at high-resolution (up to R=150000) and large spectral range (from the blue limit to the K band) useful for a large suite of science cases that can exclusively be tackled by the E-ELT. We present in this paper the solution for HIRES envisaged by the "HIRES initiative", the international collaboration established in 2013 to pursue a HIRES on E-ELT.

Zerbi, F. M.; Bouchy, F.; Fynbo, J.; Maiolino, R.; Piskunov, N.; Rebolo Lopez, R.; Santos, N.; Strassmeier, K.; Udry, S.; Vanzi, L.; Riva, M.; Basden, A.; Boisse, I.; Bonfils, X.; Buscher, D.; Cabral, A.; Dimarcantonio, P.; Di Varano, I.; Henry, D.; Monteiro, M.; Morris, T.; Murray, G.; Oliva, Ernesto; Parry, I.; Pepe, F.; Quirrenbach, A.; Rasilla, J. L.; Rees, P.; Stempels, E.; Valenziano, L.; Wells, M.; Wildi, F.; Origlia, L.; Allende Prieto, C.; Chiavassa, A.; Cristiani, S.; Figueira, P.; Gustafsson, B.; Hatzes, A.; Haehnelt, M.; Heng, K.; Israelian, G.; Kochukhov, O.; Lovis, C.; Marconi, A.; Martins, C. J. A. P.; Noterdaeme, P.; Petitjean, P.; Puzia, T.; Queloz, D.; Reiners, A.; Zoccali, M.

2014-08-01

260

Theoretical Problems in High Resolution Solar Physics, 2  

NASA Technical Reports Server (NTRS)

The Science Working Group for the High Resolution Solar Observatory (HRSO) laid plans beginning in 1984 for a series of workshops designed to stimulate a broadbased input from the scientific community to the HRSO mission. These workshops have the dual objectives of encouraging an early start on the difficult theoretical problems in radiative transfer, magnetohydrodynamics, and plasma physics that will be posed by the HRSO data, and maintaining current discussions of results in high resolution solar studies. This workshop was the second in the series. The workshop format presented invited review papers during the formal sessions and contributed poster papers for discussions during open periods. Both are presented.

Athay, G. (editor); Spicer, D. S. (editor)

1987-01-01

261

High Resolution Urban Feature Extraction for Global Population Mapping using High Performance Computing  

SciTech Connect

The advent of high spatial resolution satellite imagery like Quick Bird (0.6 meter) and IKONOS (1 meter) has provided a new data source for high resolution urban land cover mapping. Extracting accurate urban regions from high resolution images has many applications and is essential to the population mapping efforts of Oak Ridge National Laboratory's (ORNL) LandScan population distribution program. This paper discusses an automated parallel algorithm that has been implemented on a high performance computing environment to extract urban regions from high resolution images using texture and spectral features

Vijayaraj, Veeraraghavan [ORNL; Bright, Eddie A [ORNL; Bhaduri, Budhendra L [ORNL

2007-01-01

262

High-resolution imaging of the supercritical antisolvent process  

Microsoft Academic Search

A high-magnification and high-resolution imaging technique was developed for the supercritical fluid antisolvent (SAS) precipitation process. Visualizations of the jet injection, flow patterns, droplets, and particles were obtained in a high-pressure vessel for polylactic acid and budesonide precipitation in supercritical CO2. The results show two regimes for particle production: one where turbulent mixing occurs in gas-like plumes, and another where

Philip W. Bell; Amendi P. Stephens; Christopher B. Roberts; Steve R. Duke

2005-01-01

263

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

264

Performance of the high-resolution SX700/II monochromator  

NASA Astrophysics Data System (ADS)

This article reports on the high-resolution performance of the grazing-incidence plane grating monochromator SX700/II, installed at BESSY by the Freie Universitt Berlin, in the photon energy range from about 40 to 900 eV. The high resolving power up to 10 000 achieved with this monochromator is based on improving the figure error of the ellipsoidal focusing mirror, on reducing the vertical dimension of the beam source, and on employing a 5-?m exit slit. We report on high-resolution gas-phase studies in the double-excitation region of He, as well as at core-excitation thresholds of Ne, Ar, Kr, and Xe in the photon-energy range from ?45 eV to ?900 eV. In addition, high-resolution core-excitation spectra at the K thresholds of C, N, and O are presented for gas-phase CO, N2, and O2. In all cases, high-n Rydberg states and/or vibrational sidebands of the electronic excitations were resolved. The various contributions to the present instrumental linewidths are discussed as well as the prospects for further improvements in resolution with this monochromator.

Domke, M.; Mandel, T.; Puschmann, A.; Xue, C.; Shirley, D. A.; Kaindl, G.; Petersen, H.; Kuske, P.

1992-01-01

265

High-Resolution Infrared Spectroscopy with Synchrotron Sources  

SciTech Connect

Most applications of synchrotron radiation lie in the ultraviolet and X-ray region, but it also serves as a valuable continuum source of infrared (IR) light which is much brighter (i.e. more highly directional) than that from normal thermal sources. The synchrotron brightness advantage was originally exploited for high spatial resolution spectroscopy of condensed-phase samples. But it is also valuable for high spectral resolution of gas-phase samples, particularly in the difficult far-IR (terahertz) range (1/{lambda} {approx} 10-1000 cm{sup -1}). Essentially, the synchrotron replaces the usual thermal source in a Fourier transform IR spectrometer, giving a increase of up to two (or even more) orders of magnitude in signal at very high-resolution. Following up on pioneering work in Sweden (MAX-lab) and France (LURE), a number of new facilities have recently been constructed for high-resolution gas-phase IR spectroscopy. In the present paper, this new field is reviewed. The advantages and difficulties associated with synchrotron IR spectroscopy are outlined, current and new facilities are described, and past, present, and future spectroscopic results are summarized.

McKellar, A.

2010-01-01

266

Remote Measurements of the Atmosphere with High Spatial Resolution  

NASA Astrophysics Data System (ADS)

Global atmosphere-ocean models are now operating at 3.5 km resolution and mesoscale weather prediction models operating at 1.7 km resolution have been used for the analysis of hurricanes. One can expect that weather prediction models will operate at resolutions better than 5 km during the coming decade. Microwave sensors have contributed valuable information about rainfall and sea surface winds. The Precipitation Radar (PR) onboard the Tropical Rainfall Measuring Mission (TRMM) can address this need. However it may be nearing the end of its life, and its replacement by the Global Precipitation Measurement (GPM) mission is expected no earlier than 2013. Recently the four Italian Cosmo-SkyMed, and the German Terra-SAR X-band synthetic aperture radars (SARs) have displayed rain distributions with resolution better than 0.5 km. The Quickscat also now provides distributions of rainfall and sea surface winds with 2.5 km resolution. We will describe rainfall retrieval algorithms, show rainfall distributions retrieved from Terra-SAR, and discuss errors in those measurements. We will also describe multi-frequency radar measurements of sea surface winds and rainfall during hurricanes. Although most remotely sensed rainfall and wind data can be expected to be obtained from satellites, unmanned aerial vehicles (UAVs) with one week cruising duration and ~180 kg payloads flying at 18 km height may become attractive platforms from which severe weather can be tracked with high resolution.

Weinman, J. A.; Marzano, F. S.; Mugnai, A.

2009-09-01

267

High resolution photoabsorption spectroscopy at the carbon K-Edge  

NASA Astrophysics Data System (ADS)

Using plane grating, ellipsoidal mirror, grazing incidence monochromators at the storage ring BESSY, a resolution of ? 150meV was achieved for a photon energy of 285 eV. This high energy resolution considerably extends the range of possible studies using core level Spectroscopy. Some of the new opportunities are illustrated at the C K edge by resolving the vibrational fine structure of condensed C2H4 multilayers in the (1s-1, ?*) state by means of photoabsorption spectroscopy. For the sake of comparison with other high resolution instruments, the vibrational fine structure of condensed N2 multilayers at the N K edge ( 400eV) was also measured, yielding a resolving power of 3000.

Arvanitis, D.; Rabus, H.; Domke, M.; Puschmann, A.; Comelli, G.; Petersen, H.; Trger, L.; Lederer, T.; Kaindl, G.; Baberschke, K.

1989-10-01

268

High Resolution Coherent Three-Dimensional Spectroscopy of Iodine  

NASA Astrophysics Data System (ADS)

The heavy congestion found in many one-dimensional spectra can make it difficult to study many transitions. A new coherent three-dimensional spectroscopic technique has been developed to eliminate the kind of congestion commonly seen in high resolution electronic spectra. The molecule used for this test was Iodine. A well-characterized transition (X to B) was used to determine which four wave mixing process or processes were responsible for the peaks in the resulting multidimensional spectrum. The resolution of several peaks that overlap in a coherent 2D spectrum can be accomplished by using a higher dimensional (3D) spectroscopic method. This talk will discuss strategies for finding spectroscopic constants using this high resolution coherent 3D spectroscopic method.

House, Zuri R.; Wells, Thresa A.; Chen, Peter C.; Strangfeld, Benjamin R.

2013-06-01

269

High Resolution VUV Spectrometer at the INDUS-1 Synchrotron Source  

SciTech Connect

An indigenously developed high-resolution vacuum ultraviolet (VUV) spectrometer has recently been commissioned at the INDUS-1 Synchrotron Source, Indore, India for carrying out spectroscopic research of atomic and molecular gases. The spectrometer uses a 6.65-meter concave grating in off-plane Eagle mounting and a photomultiplier tube (PMT) for recording the intensity profile of various spectral lines. Experimental performance of the spectrometer has been tested using laboratory sources and 1200 grooves/mm and 4800 grooves/mm concave gratings. Wavelength resolutions of 0.08 Aa and 0.01 Aa have been achieved when 1200 grooves/mm and 4800 grooves/mm concave gratings have been mounted successfully in the spectrometer. The instrument has been integrated with the high resolution VUV beamline at INDUS-1 and its performance is being evaluated with synchrotron radiation.

Das, Nimai C.; Shukla, Ram P.; Udupa, Dinesh V.; Sahoo, Naba K.; Bhattacharyya, Dibyendu; Sunanda, K.; Saraswathy, P. [Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai -400 085 (India)

2007-01-19

270

Resonant Double Photoionization of Li Studied with High Energy Resolution  

NASA Astrophysics Data System (ADS)

Employing monochromatized synchrotron radiation of the new VLS-PGM beamline at the Synchrotron Radiation Center (SRC), we have measured with high energy resolution the relative photoionization cross-sections for the formation of Li^+ and Li^2+ ions between 148 and 161 eV photon energy. This energy region is characterized by double and triple excitations that lead to strong enhancements in the cross sections, particularly in the Li^2+ cross section. In an earlier study performed by Huang et al. only a moderate energy resolution was used. Our high-resolution data exhibit a dramatic resonance structure in the double-to-single ionization ratio not seen before. M.-T. Huang, R. Wehlitz, Y. Azuma, L. Pibida, I.A. Sellin, J.W. Cooper, M. Koide, H. Ishijima, and T. Nagata, Phys. Rev. A 59, 3397 (1999)

Wehlitz, R.; Jurani?, P. N.

2006-05-01

271

Portable electro-mechanically cooled high-resolution germanium detector  

NASA Astrophysics Data System (ADS)

We have integrated a small, highly-reliable, electro-mechanical cryo-cooler with a high-resolution germanium detector for portable/field applications. The system weighs 6.8 kg and requires 40 watts of power to operate once the detector is cooled to its operating temperature. The detector is a 500 mm(exp 2) by 20-mm thick low-energy configuration that gives a full-width at half maximum (FWHM) energy resolution of 523 eV at 122 keV, when cooled with liquid nitrogen. The energy resolution of the detector, when cooled with the electro-mechanical cooler, is 570 eV at 122 keV. We have field tested this system in measurements of plutonium and uranium for isotopic and enrichment information using the MGA and MGAU analysis programs without any noticeable effects on the results.

Neufeld, K. W.; Ruhter, W. D.

1995-05-01

272

High Resolution Muon Computed Tomography at Neutrino Beam Facilities  

E-print Network

X-ray computed tomography (CT) has an indispensable role in constructing 3D images of objects made from light materials. However, limited by absorption coefficients, X-rays cannot deeply penetrate materials such as copper and lead. Here we show via simulation that muon beams can provide high resolution tomographic images of dense objects and of structures within the interior of dense objects. The effects of resolution broadening from multiple scattering diminish with increasing muon momentum. As the momentum of the muon increases, the contrast of the image goes down and therefore requires higher resolution in the muon spectrometer to resolve the image. The variance of the measured muon momentum reaches a minimum and then increases with increasing muon momentum. The impact of the increase in variance is to require a higher integrated muon flux to reduce fluctuations. The flux requirements and level of contrast needed for high resolution muon computed tomography are well matched to the muons produced in the pion decay pipe at a neutrino beam facility and what can be achieved for momentum resolution in a muon spectrometer. Such an imaging system can be applied in archaeology, art history, engineering, material identification and whenever there is a need to image inside a transportable object constructed of dense materials.

Burkhant Suerfu; Christopher G. Tully

2015-01-28

273

A compact high-resolution X-ray powder diffractometer  

PubMed Central

A new powder diffractometer operating in transmission mode is described. It can work as a rapid very compact instrument or as a high-resolution instrument, and the sample preparation is simplified. The incident beam optics create pure Cu K?1 radiation, giving rise to peak widths of ?0.1 in 2? in compact form with a sample-to-detector minimum radius of 55?mm, reducing to peak widths of <0.05 in high-resolution mode by increasing the detector radius to 240?mm. The resolution of the diffractometer is shown to be governed by a complex mixture of angular divergence, sample size, diffraction effects and the dimensions of the detector pixels. The data can be collected instantaneously, which combined with trivial sample preparation and no sample alignment, makes it a suitable method for very rapid phase identification. As the detector is moved further from the sample, the angular step from the pixel dimension is reduced and the resolution improves significantly for very detailed studies, including structure determination and analysis of the microstructure. The advantage of this geometry is that the resolution of the diffractometer can be calculated precisely and the instrumental artefacts can be analysed easily without a sample present. The performance is demonstrated with LaB6 and paracetamol, and a critical appraisal of the uncertainties in the measurements is presented. The instantaneous data collection offers possibilities in dynamic experiments. PMID:24282331

Fewster, Paul F.; Trout, David R. D.

2013-01-01

274

Exploring for subtle traps with high-resolution paleogeographic maps  

Microsoft Academic Search

High-resolution paleogeographic maps depicting the depositional history of the Reklaw 1 interval provide a basis for prospecting for subtle traps in the updip Reklaw trend in south Texas. The Reklaw 1 interval began with sand being carried southwest by longshore currents to form the barrier bar that forms the reservoir in Atkinson field. The hydrocarbons are trapped by the updip

T. B. Bulling; J. A. Breyer

1988-01-01

275

HIGH RESOLUTION FORWARD AND INVERSE EARTHQUAKE MODELING ON TERASCALE COMPUTERS  

E-print Network

motion during earthquakes in such large basins as Los Angeles. This problem is of great importanceHIGH RESOLUTION FORWARD AND INVERSE EARTHQUAKE MODELING ON TERASCALE COMPUTERS VOLKAN AKC¸ ELIK, JULIO L ´OPEZ¶, DAVID O'HALLARON , TIANKAI TU, AND JOHN URBANIC Abstract. For earthquake simulations

Shewchuk, Jonathan

276

High-resolution microscopy and early-stage precipitation kinetics  

NASA Astrophysics Data System (ADS)

Experimental work by high-resolution microscopy is summarized to check nucleation kinetics in solid/solid phase transformations in alloys; in particular, the NiAl, CuCo, and CuTi systems are discussed. Recent theoretical work makes it possible to analyze decomposition kinetics also in the more general case that nucleation, growth, and Ostwald ripening are concomitant processes.

Haasen, P.; Wagner, R.

1992-07-01

277

April 8, 2003 Flow Textures: High Resolution Flow Visualization  

E-print Network

1 April 8, 2003 Flow Textures: High Resolution Flow Visualization Gordon Erlebacher, Bruno Jobard, and Daniel Weiskopf To appear in the Handbook of Visualization, Academic Press, late 2003. Editors: Chris the development of a growing num- ber of visualization techniques to better understand their spatio

Erlebacher, Gordon

278

Septum Orbitale: High-Resolution MR in Orbital Anatomy  

Microsoft Academic Search

PURPOSE: The purpose of this study was to ascertain whether MR imaging, with the use of a surface coil, can accurately show small intraorbital structures; in particular, the septum orbitale. METHODS: Examinations of 26 patients who underwent unilateral orbital high-resolution MR imaging for different indications were evaluated to differentiate the septum orbitale from related structures, such as the aponeurosis of

N. Hosten; B. Sander; C. Zwicker; R. Felix

279

Fabrication of Probes for High Resolution Optical Microscopy  

E-print Network

Fabrication of Probes for High Resolution Optical Microscopy Physics 564 Applied Optics Professor is ~/2--for an imaging system that uses visible light. NSOM uses a metal coated aluminum fiber optic tip of the image plane. Thus the tip of the fiber has to be very close to the object being imaged. This close

La Rosa, Andres H.

280

High-resolution tunable fiber Bragg grating filter  

Microsoft Academic Search

High resolution tunable optical filters are important in dense wavelength division multiplexing (DWDM) applications as channel spacing in optical communications systems can be as low as 0.4nm. The bandwidth of the filter must be narrow, to prevent filtering neighbouring channels. In this paper, a simple, low cost technique for the tuning of the Bragg wavelength of the FBG filter with

Chia M. Tay; Khay M. Tan; Swee C. Tjin; Chi Chiu Chan; Nam Quoc Ngo; Xinyong Dong

2004-01-01

281

Overshooting Convection from High-resolution NEXRAD Observations  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1 Tropopause Calculation Validation . . . . . . . . . . . . . . . . . . . 11 4.2 Radar Coverage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5... by NOAA. Black box designates the geographical area encompassed in this study. 6 4.1 Comparison of ERA-Interim high-resolution calculated tropopause height to NOAA balloon sonde tropopause height. Red lines denote a 1 km boundary around perfect agreement...

Solomon, David

2014-01-09

282

Optical Design of the Submillimeter High Angular Resolution Camera (SHARC)  

Microsoft Academic Search

The optical and mechanical design and performance of the Submillimeter High Angular Resolution Camera (SHARC) is described. The camera currently operates with a monolithic 24-pixel linear bolometer array in the 350 and 450 micron atmospheric windows at the Caltech Submillimeter Observatory (CSO). The design extends the techniques of geometric optics employed in optical and near-infrared cameras to submillimeter wavelengths. Using

T. R. Hunter; D. J. Benford; E. Serabyn

1996-01-01

283

Greenland Observed at High Resolution by the Seasat Scatterometer  

E-print Network

-scale variations in arctic ice and facilitate our understanding of global climate change. INTRODUCTI0N The SeasatGreenland Observed at High Resolution by the Seasat Scatterometer D.G. Long', P.J. Hardin2, and RA to SASS data for the study of Greenland's ice sheet. We present a time series of the radar backscatter

Long, David G.

284

High energy-resolution inelastic x-ray scattering  

SciTech Connect

A brief review is presented of various aspects of high energy-resolution inelastic x-ray scattering based on synchrotron sources. We show what kinematical advantages are provided by the photon probe and propose mirror and monochromator designs to achieve an optically efficient beam line for inelastic x-ray scattering.

Hastings, J.B.; Moncton, D.E.; Fujii

1984-01-01

285

Workshop on high-resolution, large-acceptance spectrometers  

SciTech Connect

The purpose of the Workshop on High-Resolution, Large-Acceptance Spectrometers was to provide a means for exchange of information among those actively engaged in the design and construction of these new spectrometers. Thirty-seven papers were prepared for the data base.

Zeidman, B. (ed.)

1981-01-01

286

HIGH RESOLUTION VERTICLE PROFILES OF PH IN RECENT SEDIMENTS  

EPA Science Inventory

High resolution (0.1 cm sampling interval) profiles of pH were obtained from some recent estuarine (Long Island Sound, Chesapeake Bay) and freshwater (Lake Erie) sediments and from laboratory microcosms containing homogenized Lake Erie sediment (both with and without tubificid ol...

287

Development of high accuracy and resolution geoid and gravity maps  

NASA Technical Reports Server (NTRS)

Precision satellite to satellite tracking can be used to obtain high precision and resolution maps of the geoid. A method is demonstrated to use data in a limited region to map the geopotential at the satellite altitude. An inverse method is used to downward continue the potential to the Earth surface. The method is designed for both satellites in the same low orbit.

Gaposchkin, E. M.

1986-01-01

288

Shallow water High Resolution Bathymetric Side Scan Sonar  

Microsoft Academic Search

With about 2 years' work, the Instituted of Acoustic, Chinese Academy of Sciences (IACAS) and the Teledyne RD Technology (Shanghai) Inc. (RDT) have developed the Shallow water High Resolution Bathymetric Side Scan Sonar (SBSSS). It is mainly composed of sonar deck control unit, sonar housing (include electronic unit and watertight pod) and two sonar arrays. The SBSSS can obtain the

Xiaodong Liu; Weiqing Zhu; Changle Fang; Wen Xu; Fangsheng Zhang; Yujia Sun

2007-01-01

289

High resolution measurements in liquid metal by focused ultrasonic wave  

Microsoft Academic Search

High spatial resolution measurements in molten zinc at temperatures more than 600 C are performed using a focused ultrasonic pulse-echo technique with clad metallic buffer rods. The focused ultrasonic waves are generated by a spherical acoustic lens which is fabricated at the end of the buffer rod. In order to evaluate its focussing ability, several experiments are carried out in

I. Ihara; C.-K. Jen; D. Ramos Frana

2000-01-01

290

Galactic nuclei and quasars at high angular resolution  

NASA Astrophysics Data System (ADS)

Astrophysics and cosmology progress expected from high angular resolution observations in the optical and ultraviolet ranges is discussed. Gravitational lenses, gas and star motions in active nuclei; physics of jets; determination of the mass of individual compact objects in the dark halos of galaxies, and estimation of the fraction of the mass of the Universe which is in baryonic form are mentioned.

Ulrich, M. H.

1987-08-01

291

High-Resolution Land Use and Land Cover Mapping  

USGS Publications Warehouse

As the Nation?s population grows, quantifying, monitoring, and managing land use becomes increasingly important. The U.S. Geological Survey (USGS) has a long heritage of leadership and innovation in land use and land cover (LULC) mapping that has been the model both nationally and internationally for over 20 years. At present, the USGS is producing high-resolution LULC data for several watershed and urban areas within the United States. This high-resolution LULC mapping is part of an ongoing USGS Land Cover Characterization Program (LCCP). The four components of the LCCP are global (1:2,000,000-scale), national (1:100,000-scale), urban (1:24,000-scale), and special projects (various scales and time periods). Within the urban and special project components, the USGS Rocky Mountain Mapping Center (RMMC) is collecting historical as well as contemporary high-resolution LULC data. RMMC?s high-resolution LULC mapping builds on the heritage and success of previous USGS LULC programs and provides LULC information to meet user requirements.

U.S. Geological Survey

1999-01-01

292

Pulmonary Gaucher's disease: High-resolution computed tomographic features  

Microsoft Academic Search

CT findings in pulmonary Gaucher's disease have not been previously reported. Chest radiograph of a patient with pulmonary involvement in type I Gaucher's disease proven by biopsy showed linear and reticulo-nodular opacities. High-resolution CT demonstrated thickening of the interlobular septa and between four and six small nodules within secondary lobules, probably each corresponding to an acinus.

A. Tunaci; Y. M. Berkmen; E. Gkmen

1995-01-01

293

Lung findings on high resolution CT in early ankylosing spondylitis  

Microsoft Academic Search

Objective: Ankylosing spondylitis (AS) is a chronic inflammatory disease mainly affecting the axial skeleton and pulmonary involvement is a well known feature of the disease. The aim of this study was to investigate the pulmonary high resolution computed tomography (HRCT) findings of patients with early AS. The relationship between pulmonary function tests (PFT) and HRCT findings was also determined. Subjects

Adem Kiris; Salih Ozgocmen; Ercan Kocakoc; Ozge Ardicoglu; Erkin Ogur

2003-01-01

294

High resolution image processing of geophysical data with diffraction tomography  

Microsoft Academic Search

This paper presents a method of detection and imaging that has as its input the data collected from the most commonly employed geophysical tools. The method makes use of the Generalized Projection Slice Theorem (GPST) in the analysis of these data to yield results ranging from greatly improved detection to high resolution images of subsurface features and buried objects. Detection

A. J. Witten; W. C. King; J. R. Ursic

1992-01-01

295

High Resolution Digital Imaging of Paintings: The Vasari Project.  

ERIC Educational Resources Information Center

Describes VASARI (the Visual Art System for Archiving and Retrieval of Images), a project funded by the European Community to show the feasibility of high resolution colormetric imaging directly from paintings. The hardware and software used in the system are explained, storage on optical disks is described, and initial results are reported. (five

Martinez, Kirk

1991-01-01

296

Plant respirometer enables high resolution of oxygen consumption rates  

NASA Technical Reports Server (NTRS)

Plant respirometer permits high resolution of relatively small changes in the rate of oxygen consumed by plant organisms undergoing oxidative metabolism in a nonphotosynthetic state. The two stage supply and monitoring system operates by a differential pressure transducer and provides a calibrated output by digital or analog signals.

Foster, D. L.

1966-01-01

297

HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS  

SciTech Connect

This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

SCHOFIELD JS

2007-10-04

298

High-resolution, multi-scale modeling of watershed hydrology  

E-print Network

High-resolution, multi-scale modeling of watershed hydrology CUAHSI Cyber Seminar October 3, 2003 and Distributed Modeling in a Hydrologic Observatory Assistant Professor of Hydrology Department of Earth and Environmental Science New Mexico Institute of Mining and Technology #12;2 Real and Virtual Hydrologic

Vivoni, Enrique R.

299

High-resolution elasticity imaging for tissue engineering  

Microsoft Academic Search

An elasticity microscope provides high resolution images of tissue elasticity. With this instrument, it may be possible to monitor cell growth and tissue development in tissue engineering. To test this hypothesis, elasticity micrographs were obtained in two model systems commonly used for tissue engineering. In the first, strain images of a tissue-engineered smooth muscle sample clearly identified a several hundred

N. Abraham Cohn; B.-S. Kim; R. Q. Erkamp; D. J. Mooney; S. Y. Emelianov; A. R. Skovoroda; M. O'Donnell

2000-01-01

300

Measuring Suspended Sediments Using High Resolution Acoustic Velocimeters  

E-print Network

Slade OASIS Field Work Funded by ONR #12;Benefits of Using Acoustics to Study Marine ParticlesMeasuring Suspended Sediments Using High Resolution Acoustic Velocimeters Clementina R. Russo to composition than optics, y p p #12;Acoustic Velocimeters for Mass Analysis Acoustic Velocimeter Bistatic

Boss, Emmanuel S.

301

High resolution bone mineral densitometry with a gamma camera  

NASA Technical Reports Server (NTRS)

A technique by which the regional distribution of bone mineral can be determined in bone samples from small animals is described. The technique employs an Anger camera interfaced to a medical computer. High resolution imaging is possible by producing magnified images of the bone samples. Regional densitometry of femurs from oophorectomised and bone mineral loss.

Leblanc, A.; Evans, H.; Jhingran, S.; Johnson, P.

1983-01-01

302

Nanoparticle delivery Nanofountain-Probe-Based High-Resolution Patterning  

E-print Network

Nanoparticle delivery Nanofountain-Probe-Based High-Resolution Patterning and Single-Cell Injection therapeutics and drug delivery. However, developing future nanoscale devices and arrays that harness and continuous delivery via microfluidic components. To address this, two modes of controlled delivery

Espinosa, Horacio D.

303

High-spectral-resolution multiplex CARS spectroscopy using chirped pulses  

Microsoft Academic Search

A novel technique for achieving high spectral resolution with a femtosecond laser system is presented. Transform-limited 800 nm, 90 femtosecond (fs) pulses pass off two gratings, stretching the pulse in time to a pulse width of several picoseconds due to an induced linear temporal chirp directly proportional to the grating separation. This chirped pulse is the degenerate pump (omegaP) and

Kelly P. Knutsen; Justin C. Johnson; Abigail E. Miller; Poul B. Petersen; Richard J. Saykally

2004-01-01

304

High Resolution Methods and Adaptive Refinement for Tsunami Propagation and  

E-print Network

High Resolution Methods and Adaptive Refinement for Tsunami Propagation and Inundation. David L volume methods and adaptive refinement for the shallow water equations in the context of tsunami modeling contexts, however, tsunami modeling presents some unique challenges that must be overcome. We describe some

LeVeque, Randy

305

Performance of the WIYN high-resolution infrared camera  

Microsoft Academic Search

We present the design overview and on-telescope performance of the WIYN High Resolution Infrared Camera (WHIRC). As a dedicated near-infrared (0.8-2.5 mum) camera on the WIYN Tip-Tilt Module (WTTM), WHIRC will provide near diffraction-limited imaging with a typical FWHM of ~0.25\\

Margaret Meixner; Stephen Smee; Ryan L. Doering; Robert H. Barkhouser; Todd Miller; Joseph Orndoff; Patricia Knezek; Edward Churchwell; Gregg Scharfstein; Jeff Percival; David Mills; Charles Corson

2008-01-01

306

Solar magnetic field strength determinations from high spatial resolution filtergrams  

Microsoft Academic Search

Circularly polarized images with high spatial resolution (better than 1 arcsec) of a solar active region, obtained with a tunable filter in the wings of Fe I 5247.1 A and Fe I 5250.2 A, have been analyzed in terms of the magnetic line ratio technique introduced by Stenflo (1973). Whenever a measurable amount of polarization is present, the distribution of

C. U. Keller; J. O. Stenflo; S. K. Solanki; T. D. Tarbell

1990-01-01

307

High-resolution SPECT using multi-pinhole collimation  

Microsoft Academic Search

We present a novel SPECT imaging technique for small animal research based on multi-pinhole collimation. This new method is an extension of single-pinhole tomography and combines high-resolution with increased system sensitivity. This paper describes the multi-pinhole imaging system and its characterization on simulated and measured phantom data.

N. U. Schramm; G. Ebel; U. Engeland; T. Schurrat; M. Behe; T. M. Behr

2002-01-01

308

A High-Resolution Single Nucleotide Polymorphism Genetic Map  

E-print Network

, Jordana Tzenova Bell1 , Richard R. Copley1 , Martin S. Taylor1 , Robert W. Williams2 , Richard Mott1, 2 Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America High-resolution genetic maps are required for mapping complex traits

Nachman, Michael

309

Optical diffraction tomography for high resolution live cell imaging  

E-print Network

Optical diffraction tomography for high resolution live cell imaging Yongjin Sung1 , Wonshik Choi1 diffraction tomography for quantitative 3D mapping of refractive index in live biological cells. Using in live cells, we apply optical diffraction tomography based on the Rytov approximation. In this way

Fang-Yen, Christopher

310

Application of superlattice multipliers for high-resolution terahertz spectroscopy.  

PubMed

Frequency multipliers based on superlattice (SL) devices as nonlinear elements have been developed as radiation sources for a terahertz (THz) laboratory spectrometer. Input frequencies of 100 and 250 GHz from backward wave oscillators have been multiplied up to the 11th harmonic, producing usable frequencies up to 2.7 THz. Even at these high frequencies the output power is sufficient for laboratory spectroscopy. Comparisons to conventional high-resolution microwave spectroscopy methods reveal several superior features of this new device such as very high line frequency accuracies, broadband tunability, high output power levels at odd harmonics of the input frequency up to high orders, and a robust applicability. PMID:17477648

Endres, C P; Lewen, F; Giesen, T F; Schlemmer, S; Paveliev, D G; Koschurinov, Y I; Ustinov, V M; Zhucov, A E

2007-04-01

311

High-Resolution MRI of Intracranial Atherosclerotic Disease  

PubMed Central

Intracranial atherosclerotic disease (ICAD) causes up to 10% of all ischemic strokes, and the rate of recurrent vascular ischemic events is very high. Important predictors of vulnerability in atherosclerotic plaques include the degree of stenosis and the underlying plaque morphology. Vascular wall MRI can provide information about wall structures and atherosclerotic plaque components. High-resolution (HR)-MRI in ICAD poses a greater challenge in the neurologic fields, because a high in-plane resolution and a high signal-to-noise ratio are required for vessel wall imaging of ICAD. Until now, plaque imaging of ICAD has focused on assessing the presence of a plaque and evaluating the plaque load. Going forward, evaluation of plaque vulnerability through analysis of imaging characteristics will be a critical area of research. This review introduces the acquisition protocol for HR-MRI in ICAD and the current issues associated with imaging. PMID:24644529

Kwak, Hyo-Sung; Jahng, Geon-Ho; Lee, Han Na

2014-01-01

312

Statistical properties of multifrequency high-range-resolution sea reflections  

NASA Astrophysics Data System (ADS)

The statistical properties of multifrequency high-range-resolution, low-grazing-angle measurements of sea clutter are presented. It is shown that the compound form of the K-distribution provides an excellent description for measurements made at S, X and J bands for all the radar range resolutions employed (0.375 m to 15 m). It is also shown that the K-distribution shape parameter tends to decrease as the illuminated patch is made smaller, corresponding to an increase in spikiness of the backscatter. This change in shape parameter appears to be a function of the underlying modulation with the speckle component remaining largely unchanged.

Hair, T.; Lee, T.; Baker, C. J.

1991-04-01

313

Developments in high resolution NMR of inorganic solids  

SciTech Connect

From the foundations laid by the pioneering work of J.S. Waugh at M.I.T., a number of advances in resolution and sensitivity have contributed to modem solid state nuclear magnetic resonance (NMR) and its applications to materials science. Among the recent developments at Berkeley aimed at high resolution spectroscopy in solids are multiple-quantum NMR, cross polarization of quadrupoles, multiple-axis spinning methods, zero field magnetic resonance and optically pumped xenon NMR of surfaces. Following the lecture we shall hear an update on the condition of Hartmann and Hahn.

Pines, A. [Lawrence Berkeley National Lab., CA (United States)

1996-12-31

314

Solutions on high-resolution multiple configuration system sensors  

NASA Astrophysics Data System (ADS)

For aim to achieve an improved resolution in modern image domain, a method of continuous zoom multiple configuration, with a core optics is attempt to establish model by novel principle on energy transfer and high accuracy localization, by which the system resolution can be improved with a level in nano meters. A comparative study on traditional vs modern methods can demonstrate that the dialectical relationship and their balance is important, among Merit function, Optimization algorithms and Model parameterization. The effect of system evaluated criterion that MTF, REA, RMS etc. can support our arguments qualitatively.

Liu, Hua; Ding, Quanxin; Guo, Chunjie; Zhou, Liwei

2014-11-01

315

Measurement of stratospheric HBr using high resolution far infrared spectroscopy  

Microsoft Academic Search

Far infrared spectral features of HBr have been observed in the stratospheric emission spectrum using a balloon borne high resolution Fourier transform spectrometer equipped with a high sensitivity detector specially designed for this purpose. The value of 1.6+\\/-0.6 parts per trillion in volume for the HBr mixing ratio has been retrieved, from the global-fit analysis of 121 spectra, in the

M. Carlotti; P. A. R. Ade; B. Carli; P. Ciarpallini; U. Cortesi; M. J. Griffin; G. Lepri; F. Mencaraglia; A. G. Murray; I. G. Nolt; J. H. Park; J. V. Radostitz

1995-01-01

316

High-resolution schemes for hyperbolic conservation laws  

NASA Technical Reports Server (NTRS)

A class of new explicit second order accurate finite difference schemes for the computation of weak solutions of hyperbolic conservation laws is presented. These highly nonlinear schemes are obtained by applying a nonoscillatory first order accurae scheme to an appropriately modified flux function. The so derived second order accurate schemes achieve high resolution while preserving the robustness of the original nonoscillatory first order accurate scheme.

Harten, A.

1982-01-01

317

A New Bandgap Reference for High-Resolution Data Converters  

Microsoft Academic Search

In this paper, a CMOS bandgap reference (BGR) for high-resolution data-converters is proposed and analyzed. The proposed BGR circuit is derived and modified from a recently developed low-voltage BGR. It combines two different branches of conventional BGR into one PMOS transistor, avoiding the matching requirement of the current mirror. The low temperature-susceptible current is used to generate high and low

Chenchang Zhan; Wei Wang; Xiaofang Zhou; Dian Zhou

2007-01-01

318

Topics in high resolution spectroscopy of stored ions  

NASA Astrophysics Data System (ADS)

Recent developments in stored ion spectroscop are discussed with emphasis on the following aspects: (i) Very high resolution experiments. (ii) Precision spectroscopy of one-electron ions. (iii) Measurement of the magnetic moment of the bound electron. (iv) Feasibility of external ion injection to extend ion storage techniques to highly charged and possibly radioactive ions. The question of what can be learned from these experiments about nuclear structure and quantum electrodynamical contributions to the hyperfine interaction and the atomic Zeeman effect is addressed.

Schuessler, H. A.

1985-08-01

319

High-resolution Imaging Techniques for the Assessment of Osteoporosis  

PubMed Central

Synopsis The importance of assessing the bones microarchitectural make-up in addition to its mineral density in the context of osteoporosis has been emphasized in a number of publications. The high spatial resolution required to resolve the bones microstructure in a clinically feasible scan time is challenging. Currently, the best suited modalities meeting these requirements in vivo are high-resolution peripheral quantitative imaging (HR-pQCT) and magnetic resonance imaging (MRI). Whereas HR-pQCT is limited to peripheral skeleton regions like the wrist and ankle, MRI can also image other sites like the proximal femur but usually with lower spatial resolution. In addition Multidetector-CT has been used for high-resolution imaging of trabecular bone structure, however, the radiation dose is a limiting factor. This article provides an overview of the different modalities, technical requirements and recent developments in this emerging field. Details regarding imaging protocols as well as image post-processing methods for bone structure quantification are discussed. PMID:20609895

Krug, Roland; Burghardt, Andrew J.; Majumdar, Sharmila; Link, Thomas M.

2010-01-01

320

Photoacoustic lymphatic imaging with high spatial-temporal resolution  

NASA Astrophysics Data System (ADS)

Despite its critical function in coordinating the egress of inflammatory and immune cells out of tissues and maintaining fluid balance, the causative role of lymphatic network dysfunction in pathological settings is still understudied. Engineered-animal models and better noninvasive high spatial-temporal resolution imaging techniques in both preclinical and clinical studies will help to improve our understanding of different lymphatic-related pathologic disorders. Our aim was to take advantage of our newly optimized noninvasive wide-field fast-scanning photoacoustic (PA) microcopy system to coordinately image the lymphatic vasculature and its flow dynamics, while maintaining high resolution and detection sensitivity. Here, by combining the optical-resolution PA microscopy with a fast-scanning water-immersible microelectromechanical system scanning mirror, we have imaged the lymph dynamics over a large field-of-view, with high spatial resolution and advanced detection sensitivity. Depending on the application, lymphatic vessels (LV) were spectrally or temporally differentiated from blood vessels. Validation experiments were performed on phantoms and in vivo to identify the LV. Lymphatic flow dynamics in nonpathological and pathological conditions were also visualized. These results indicate that our newly developed PA microscopy is a promising tool for lymphatic-related biological research.

Martel, Catherine; Yao, Junjie; Huang, Chih-Hsien; Zou, Jun; Randolph, Gwendalyn J.; Wang, Lihong V.

2014-11-01

321

High resolution characterization of plasmon resonances in silver nanostructures  

NASA Astrophysics Data System (ADS)

In this work, we use the iterative Richardson-Lucy (RL) deconvolution to further increase the energy resolution of electron energy loss spectra of surface plasmon resonances (SPR) in silver nanostructures. We obtain a record e_ective energy resolution of 10 meV after 500 iterations for spectral features below 1 eV. We extract energy- _ltered maps of SPR of a nanorod at energies down to 0.25 eV, corresponding to the mid-infrared region on the electromagnetic spectrum. And we are able to identify hydrid-SPR peaks separated by only 70 meV from two nano-squares with a gap of 100 nm between them, demonstrating that the RL deconvolution applied to spectra acquired with a monochromator is a useful tool to characterize plasmonic structures at low energies with high energy resolution.

Bellido, Edson P.; Rossouw, David; Botton, Gianluigi A.

2014-09-01

322

Bayesian Peptide Peak Detection for High Resolution TOF Mass Spectrometry  

PubMed Central

In this paper, we address the issue of peptide ion peak detection for high resolution time-of-flight (TOF) mass spectrometry (MS) data. A novel Bayesian peptide ion peak detection method is proposed for TOF data with resolution of 10 00015 000 full width at half-maximum (FWHW). MS spectra exhibit distinct characteristics at this resolution, which are captured in a novel parametric model. Based on the proposed parametric model, a Bayesian peak detection algorithm based on Markov chain Monte Carlo (MCMC) sampling is developed. The proposed algorithm is tested on both simulated and real datasets. The results show a significant improvement in detection performance over a commonly employed method. The results also agree with experts visual inspection. Moreover, better detection consistency is achieved across MS datasets from patients with identical pathological condition. PMID:21544266

Zhang, Jianqiu; Zhou, Xiaobo; Wang, Honghui; Suffredini, Anthony; Zhang, Lin; Huang, Yufei; Wong, Stephen

2011-01-01

323

High resolution grazing incidence telescopes for the EUV-regime  

NASA Astrophysics Data System (ADS)

With the aim of building high-resolution grazing incidence telescopes for the EUV regime, much work has been done over the past two decades to improve the angular resolution of an X-ray mirror and to understand its point spread function. Based on the performance data of the best X-ray optics (ATMS-054), Einstein-Observatory, MPI, EXOSAT), the requirements for building an EUV telescope with sub-arcsec angular resolution are estimated, and problem areas in manufacturing these telescopes are discussed. In particular, the effect of an imperfect mirror system on imaging quality is discussed, with consideration to both surface microroughness and macroscopic manufacturing tolerances. Finally, values of optical fabrication tolerances for existing X-ray mirrors are given, and means of improving these values are outlined

Aschenbach, B.

1981-12-01

324

Spatial resolution effects on the assessment of evapotranspiration in olive orchards using high resolution thermal imagery  

NASA Astrophysics Data System (ADS)

The use of remote sensing techniques for estimating surface energy balance and water consumption has significantly improved the characterization of the agricultural systems by determining accurate information about crop evapotranspiration and stress, mainly for extensive crops. However the use of these methodologies for woody crops has been low due to the difficulty in the accurate characterization of these crops, mainly caused by a coarse resolution of the imagery provided by the most widely used satellites (such as Landsat 5 and 7). The coarse spatial resolution provided by these satellite sensors aggregates into a single pixel the tree crown, sunlit and shaded soil components. These surfaces can each exhibit huge differences in temperature, albedo and vegetation indexes calculated in the visible, near infrared and short-wave infrared regions. Recent studies have found that the use of energy balance approaches can provide useful results for non-homogeneous crops (Santos et al., 2012) but detailed analysis is required to determine the effect of the spatial resolution and the aggregation of the scene components in these heterogeneous canopies. In this study a comparison between different spatial resolutions has been conducted using images from Landsat 7 (with thermal resolution of 60m) and from an airborne thermal (with resolution of 80 cm) flown over olive orchards at different dates coincident with the Landsat overpass. The high resolution thermal imagery was resampled at different scales to generate images with spatial resolution ranging from 0.8 m up to 120m (thermal resolution for Landsat 5 images). The selection of the study area was made to avoid those areas with missing Landsat 7 data caused by SLC-off gaps. The selected area has a total area of around 2500 ha and is located in Southern Spain, in the province of Malaga. The selected area is mainly cultivated with olive orchards with different crop practices (rainfed, irrigated, high density, young and adult olive, etc.). The METRIC surface energy balance approach (Allen et al., 2007) was applied for evapotranspiration assessment using the data provided by Landsat 7 and using the images from the airborne flights for three days during the summer of 2012. The flights and the Landsat 7 dates were coincident in order to avoid any difference in temperature or crop characteristic. The application of METRIC was made using detailed information from the olive orchards (mainly evapotranspiration and stress indexes) at different spatial resolutions to determine the errors generated by the aggregation process required when satellite images are considered in these studies. Recommendations are given on how to decompose the bulk surface temperature of Landsat into the component crown and soil (shaded and sunlit) components. References Allen RG, Tasumi M, Trezza R (2007) Satellite-based energy balance for mapping evapotranspiration with internalized calibration (METRIC) - Model. Journal of Irrigation and Drainage Engineering ASCE 133(4):380-394 Santos C, Lorite IJ, Allen RG, Tasumi M (2012) Aerodynamic Parameterization of the Satellite-Based Energy Balance (METRIC) Model for ET Estimation in Rainfed Olive Orchards of Andalusia, Spain. Water Resources Management 26:3267-3283

Santos, Cristina; Zarco-Tejada, Pablo J.; Lorite, Ignacio J.; Allen, Richard G.

2013-04-01

325

High-resolution imaging by multiple-image deconvolution  

NASA Astrophysics Data System (ADS)

Image deconvolution is a powerful tool for improving the quality of images corrupted by blurring and noise. However, in some cases, the imaging system is affected by anisotropic resolution, i. e. the resolution depends on the direction in the imaging plane or volume. Such a distortion cannot be corrected by image deconvolution. One example, from Astronomy, is the Large Binocular Telescope (LBT) under construction on the top of Mount Graham (Arizona). A second example, from Microscopy, is the confocal microscope. In both cases, the situation can be improved if different images of the same target can be detected by rotating the instrument or by rotating the target. Then the problem arises of obtaining a unique high-resolution image from different images taken at different orientation angles. Such a problem is called multiple-image deconvolution. In this paper, after a brief illustration of the two examples mentioned above, the problem of multiple-image deconvolution is formulated and preliminarily investigated in a continuous setting (all directions are available), showing that, while resolution is anisotropic in the multiple images, it becomes isotropic in the reconstructed image. Next, methods and algorithms for the solution of the problem are presented and their accuracy illustrated by means of the results of a few numerical experiments. Finally, the possibility of a further improvement of resolution by means of super-resolving methods is briefly discussed and demonstrated.

Bertero, M.; Boccacci, P.; Desider, G.; Vicidomini, G.

2006-10-01

326

Performance characterization of a new high resolution PET scintillation detector  

PubMed Central

Performance of a new high resolution PET detection concept is presented. In this new concept, annihilation radiation enters the scintillator detectors edge-on. Each detector module comprises two 8 8 LYSO scintillator arrays of 0.91 0.91 1 mm3 crystals coupled to two position-sensitive avalanche photodiodes (PSAPDs) mounted on a flex circuit. Appropriate crystal segmentation allows the recording of all three spatial coordinates of the interaction(s) simultaneously with submillimeter resolution. We report an average energy resolution of 14.6 1.7% for 511 keV photons at FWHM. Coincident time resolution was determined to be 2.98 0.13 ns FWHM on average. The coincidence point spread function (PSF) has an average FWHM of 0.837 0.049 mm (using a 500 ?m spherical source) and is uniform across the arrays. Both PSF and coincident time resolution degrade when Compton interactions are included in the data. Different blurring factors were evaluated theoretically, resulting in a calculated PSF of 0.793 mm, in good agreement with the measured value. PMID:20844332

Foudray, A M K; Olcott, P D

2013-01-01

327

Deep-towed High Resolution multichannel seismic imaging  

NASA Astrophysics Data System (ADS)

High Resolution (220-1050 Hz) seismic acquisition performed in deep water using deep-towed systems provides unrivalled lateral resolution when compared to conventional surface seismic. The lateral resolution of these acquisitions is controlled by the width of the first Fresnel zone, taking advantage of their positions close to the sea bottom. No current existing deep towed equipment can benefit from seismic imaging processing techniques to improve this resolution as a consequence of positioning inaccuracies. The technological developments of a digital deep-towed multichannel streamer are presented with a particular attention to positioning: each hydrophone incorporates a pitch, roll and heading sensor in order to monitor the constant deformation of the streamer in operation. The sea trials took place in July 2013 in the Mediterranean Sea. Pre-stack depth migration applied to the deep-towed multichannel data illustrates the potential of this emerging methodology in terms of penetration (12 dB improvement in Signal/Noise) and lateral resolution (mean signal wavelength: 3 m) when compared with deep-towed single-channel acquisition.

Marsset, B.; Menut, E.; Ker, S.; Thomas, Y.; Regnault, J.-P.; Leon, P.; Martinossi, H.; Artzner, L.; Chenot, D.; Dentrecolas, S.; Spychalski, B.; Mellier, G.; Sultan, N.

2014-11-01

328

High resolution meteorological modellingof the Inn Valley atmosphere, Part I  

NASA Astrophysics Data System (ADS)

Orography and local meteorology play a major role in Alpine valleys, as they are linked with valley and slope wind systems, stagnation and recirculation, temperature inversions and turbulence. Thus, they have a strong influence of transport and dilution of pollutants in the valley, affecting human health, and sound propagation. Shallow stable layers at the valley floor and low wind speed conditions, especially in autumn and winter, trap pollutants and thus cause unfavourable dispersion conditions , possibly leading to exceedances of air pollution limits. Moreover, under certain synoptic conditions such as persistent high-pressure systems inversion conditions prevail for days. Emissions may accumulate in the valley from day to day and thus critical levels of pollutants may be reached. With the current computer capabilities, numerical meteorological models and particle dispersion models are powerful tools to investigate such situations and their impact on emission-side measures. However, alpine valleys and other complex topographical areas require very high resolutions to ensure accurate representation of the physical processes. Typically, the highest resolutions used nowadays in episodic simulations with models such as, e.g., RAMS, WRF, or MM5, are around 1 km. This still smooths the orography, cutting the peaks and raising the valley bottoms. In this work a comparison of the simulation of the valley atmosphere with two meteorological models, MM5 and WRF, with high horizontal (0.6 km to 0.2 km) and vertical resolutions (35 to 39 half-s levels) is carried out for selected scenarios in which levels of pollutants exceeded air pollution limits. For a better representation of the orography SRTM 3" topography data is used in MM5 for resolutions below 1 km (~ resolution of SRTM 30" data), WRF will be tested only with SRTM 30" due to computational time constraints. The evolution of the valley atmosphere is studied using different PBL schemes available in the models as well as land-use representations. Rawinsonde data of the Innsbruck airport station and observation data of Innsbruck University and Patscherkofel will be used for comparison. These high-resolution simulations are very demanding in computational terms. Therefore, an evaluation of the computer demands of each of the simulations is also carried out. In order to asses the influence of this high resolution meteorological modelling on air quality conditions, further work with a dispersion model/chemistry model will be carried out and compared to observations (see contribution by Arnold et al., this session).

Schicker, I.; Arnold, D.; Seibert, P.

2009-09-01

329

Ultra-high resolution mass spectroscopy of boron cluster ions  

NASA Astrophysics Data System (ADS)

Boron clusters have recently received considerable attention as a possible solution to the throughput dilemma associated with ultra-low energy (sub keV) p-type source drain extension implants required by cutting edge complimentary metal-oxide semiconductor (CMOS) technology. Boron cluster ion beams contain many masses due to the binomial distribution of the two naturally occurring isotopes (masses 10 and 11) of boron. The broadness of the mass distribution peak in the dispersive plane is further complicated by a plurality of ion states, due to the varying number of hydrogen atoms remaining attached to the borohydride molecule when it is ionized. The B18Hx+ cluster ion mass spectrum from an electron impact ionization source will be analyzed in detail. An ultra-high resolution mass spectrum, exhibiting 1 AMU resolution of a mass 220 cluster ion will be shown. It will be compared to high-resolution spectra of decaborane (B 10H 14) cluster ions obtained from natural abundance decaborane and from isotopically enriched material. The deconvolution of the binominal distribution from ion states present in the cluster ion beam reveals the hydrogen distribution function. The hydrogen distribution functions as well as the binomial distributions will be presented and discussed. Physical models will be presented that explain the origin of hydrogen distribution function for these high mass borohydride cluster ions. This ultra-high mass resolution is usually unavailable to the ion implant community, however our 120 mass analyzing magnet and the extremely low emittance of the ion beam extracted from the ClusterIon source coupled with a variable width beam defining aperture and variable width mass defining slits allow for superior mass resolution.

Jacobson, Dale; Horsky, Thomas; Krull, Wade; Milgate, Bob

2005-08-01

330

Multiplex Amplicon Genotyping by High-Resolution Melting  

PubMed Central

High-resolution amplicon melting is a simple method for genotyping that uses only generic PCR primers and a saturating DNA dye. Multiplex amplicon genotyping has previously been reported in a single color, but two instruments were required: a carousel-based rapid cycler and a high-resolution melting instrument for capillaries. Manual transfer of capillaries between instruments and sequential melting of each capillary at 0.1C/s seriously limited the throughput. In this report, a single instrument that combines rapid-cycle real-time PCR with high-resolution melting [LightScanner-32 (LS-32), Idaho Technology, Salt Lake City, UT] was used for multiplex amplicon genotyping. The four most common mutations associated with thrombophilia, F5 (factor V Leiden 1691G>A), F2 (prothrombin 20210G>A), and methylenetetrahydrofolate reductase (MTHFR; 1298A>C and 677C>T) were genotyped in a single homogeneous assay with internal controls to adjust for minor chemistry and instrument variation. Forty temperature cycles required 9.2 min, and each capillary required 2.2 min by melting at 0.3C/s, 3 the prior rate. Sample volume was reduced from 20 ?l to 10 ?l. In a blinded study of 109 samples (436 genotypes), complete concordance with standard assays was obtained. In addition, the rare variant MTHFR 1317T>C was genotyped correctly when present. The LS-32 simplifies more complex high-resolution melting assays by reducing hands-on manipulation, total time of analysis, and reagent cost while maintaining the resolution necessary for multiplex amplicon genotyping. PMID:19568454

Seipp, Michael T.; Durtschi, Jacob D.; Voelkerding, Karl V.; Wittwer, Carl T.

2009-01-01

331

Laserwire: A high resolution non-invasive beam profiling diagnostic  

NASA Astrophysics Data System (ADS)

A laserwire is a non-invasive, high resolution particle beam size monitor based on Compton scattering that is required for future planned colliders and can also be used to estimate the size of the source in wakefield acceleration experiments. We present recent results from the high resolution laserwire transverse electron beam diagnostic installed at the Accelerator Test Facility 2 (ATF2) electron accelerator at KEK in Japan. Full characterisation of the propagation of the 150 mJ, 77 ps laser beam is used to deconvolve the transverse laserwire profile demonstrating the successful measurement of 1 ?m scale vertical electron beam sizes, even with extreme aspect ratios. We also present progress in the development of high energy photonic crystal fibre based laser systems for laserwire measurements at megahertz repetition rates, suitable for intra-train scanning for planned accelerators such as the International Linear Collider, or beam size measurement in laser or particle driven plasma accelerators.

Corner, L.; Aryshev, A.; Blair, G. A.; Boogert, S. T.; Karataev, P.; Kruchinin, K.; Nevay, L. J.; Terunuma, N.; Urakawa, J.; Walczak, R.

2014-03-01

332

High-resolution ultrasonic imaging using an etalon detector array  

PubMed Central

A photoacoustic imaging system was built and tested to demonstrate the feasibility of high-resolution low-noise ultrasonic imaging based on parallel detection using polymer etalons. Its capability of detecting ultrasound at different elements simultaneously in the optical end was verified by imaging three 49 ?m beads. An average noise-equivalent pressure of 3.6 kPa over 50 MHz for 50 ?m diameter detection elements in a two-dimensional array with a diameter of 1.35 mm and a detection bandwidth of 75 MHz at 3 dB was measured. These results demonstrate the potential of polymer etalons for high-frame-rate high-resolution three-dimensional photoacoustic and ultrasound pulse-echo imaging. PMID:19529842

Huang, Sheng-Wen; Hou, Yang; Ashkenazi, Shai; ODonnell, Matthew

2008-01-01

333

Coronal Heating and the Need for High-Resolution Observations  

NASA Technical Reports Server (NTRS)

Despite excellent progress in recent years in understanding coronal heating, there remain many crucial questions that are still unanswered. Limitations in the observations are one important reason. Both theoretical and observational considerations point to the importance of small spatial scales, impulsive energy release, strong dynamics, and extreme plasma nonuniformity. As a consequence, high spatial resolution, broad temperature coverage, high temperature fidelity, and sensitivity to velocities and densities are all critical observational parameters. Current instruments lack one or more of these properties, and this has led to considerable ambiguity and confusion. In this talk, I will discuss recent ideas about coronal heating and emphasize that high spatial resolution observations, especially spectroscopic observations, are needed to make major progress on this important problem.

Klimchuk, James A.

2008-01-01

334

High Resolution Optical Spectra of HBC 722 After Outburst  

NASA Astrophysics Data System (ADS)

We report the results of our high resolution optical spectroscopic monitoring campaign (? = 3800 - 8800 , R = 30000 - 45000) of the new FU Orionis-type object HBC 722. We observed HBC 722 with the BOES 1.8-m telescope between November 26 and December 29, 2010, and FU Orionis itself on January 26, 2011. We detect a number of previously unreported high-resolution K I and Ca II lines beyond 7500 . We resolve the H? and Ca II line profiles into three velocity components, which we attribute to both disk and outflow. The increased accretion during outburst can heat the disk to produce the relatively narrow absorption feature and launch outflows appearing as high velocity blue and red-shifted broad features.

Lee, Jeong-Eun; Kang, Wonseok; Lee, Sang-Gak; Sung, Hyun-Il; Lee, Byeong-Cheol; Sung, Hwankyung Sung; Green, Joel D.; Jeon, Young-Beom

2011-04-01

335

Imaging collagen type I fibrillogenesis with high spatiotemporal resolution.  

PubMed

Fibrillar collagens, such as collagen type I, belong to the most abundant extracellular matrix proteins and they have received much attention over the last five decades due to their large interactome, complex hierarchical structure and high mechanical stability. Nevertheless, the collagen self-assembly process is still incompletely understood. Determining the real-time kinetics of collagen type I formation is therefore pivotal for better understanding of collagen type I structure and function, but visualising the dynamic self-assembly process of collagen I on the molecular scale requires imaging techniques offering high spatiotemporal resolution. Fast and high-speed scanning atomic force microscopes (AFM) provide the means to study such processes on the timescale of seconds under near-physiological conditions. In this study we have applied fast AFM tip scanning to study the assembly kinetics of fibrillar collagen type I nanomatrices with a temporal resolution reaching eightseconds for a frame size of 500nm. By modifying the buffer composition and pH value, the kinetics of collagen fibrillogenesis can be adjusted for optimal analysis by fast AFM scanning. We furthermore show that amplitude-modulation imaging can be successfully applied to extract additional structural information from collagen samples even at high scan rates. Fast AFM scanning with controlled amplitude modulation therefore provides a versatile platform for studying dynamic collagen self-assembly processes at high resolution. PMID:25486377

Stamov, Dimitar R; Stock, Erik; Franz, Clemens M; Jhnke, Torsten; Haschke, Heiko

2015-02-01

336

High-resolution ionization detector and array of such detectors  

DOEpatents

A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.

McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)

2001-01-16

337

High energy resolution scintillators for nuclear nonproliferation applications  

NASA Astrophysics Data System (ADS)

The detection of ionizing radiation is important in numerous applications related to national security ranging from the detection and identification of fissile materials to the imaging of cargo containers. A key performance criterion is the ability to reliably identify the specific gamma-ray signatures of radioactive elements, and energy resolution approaching 2% at 662 keV is required for this task. In this work, we present discovery and development of new high energy resolution scintillators for gamma-ray detection. The new ternary halide scintillators belong to the following compositional families: AM2X5:Eu, AMX3, and A2MX4:Eu (A = Cs, K; M = Ca, Sr, Ba; X = Br, I) as well as mixed elpasolites Cs2NaREBr3I3:Ce (RE = La, Y). Using thermal analysis, we confirmed their congruent melting and determined crystallization and melting points. Using the Bridgman technique, we grew 6, 12 and 22 mm diameter single crystals and optimized the Eu concentration to obtain the best scintillation performance. Pulse-height spectra under gamma-ray excitation were recorded in order to measure scintillation light output, energy resolution and light output nonproportionality. The KSr2I5:Eu 4% showed the best combination of excellent crystal quality obtained at fast pulling rates and high light output of ~95,000 photons/MeV with energy resolution of 2.4% at 662 keV.

Zhuravleva, M.; Melcher, C. L.; Stand, L.; Lindsey, A.; Wei, H.; Hobbs, C.; Koschan, M.

2014-09-01

338

From high- to super-resolution mass spectrometry.  

PubMed

High-resolution mass spectrometry (MS) is indispensable for the molecular-level analysis of biological and environmental samples with great intra- and inter-molecular complexity. Here, we summarize developments in Fourier transform mass spectrometry (FTMS), the flagship of high-resolution MS techniques, accomplished in our laboratory. Particularly, we describe the recent and envisioned progress in structural analysis of: i) isolated large proteins and their simple mixtures, with a focus on monoclonal antibodies, via top-down, middle-down, and extended bottom-up mass spectrometry; ii) complex protein mixtures and proteomes via extended bottom-up proteomics; and iii) crude oil fractions and similar complex molecular mixtures. Despite the unequivocal success in molecular structural analysis, the demonstrated results clearly indicate that the compromise between MS acquisition speed (throughput) and achievable resolution level inhibits further advances of MS applications in the areas related to life, environmental, and material sciences. To further advance beyond state-of-the-art FTMS capabilities in these areas, we present the technique of super-resolution mass spectrometry that has been pioneered by our laboratory. PMID:24801850

Tsybin, Yury O

2014-01-01

339

Toshiba TDF-500 High Resolution Viewing And Analysis System  

NASA Astrophysics Data System (ADS)

A high resolution, operator interactive, medical viewing and analysis system has been developed by Toshiba and Bio-Imaging Research. This system provides many advanced features including high resolution displays, a very large image memory and advanced image processing capability. In particular, the system provides CRT frame buffers capable of update in one frame period, an array processor capable of image processing at operator interactive speeds, and a memory system capable of updating multiple frame buffers at frame rates whilst supporting multiple array processors. The display system provides 1024 x 1536 display resolution at 40Hz frame and 80Hz field rates. In particular, the ability to provide whole or partial update of the screen at the scanning rate is a key feature. This allows multiple viewports or windows in the display buffer with both fixed and cine capability. To support image processing features such as windowing, pan, zoom, minification, filtering, ROI analysis, multiplanar and 3D reconstruction, a high performance CPU is integrated into the system. This CPU is an array processor capable of up to 400 million instructions per second. To support the multiple viewer and array processors' instantaneous high memory bandwidth requirement, an ultra fast memory system is used. This memory system has a bandwidth capability of 400MB/sec and a total capacity of 256MB. This bandwidth is more than adequate to support several high resolution CRT's and also the fast processing unit. This fully integrated approach allows effective real time image processing. The integrated design of viewing system, memory system and array processor are key to the imaging system. It is the intention to describe the architecture of the image system in this paper.

Roberts, Barry; Kakegawa, M.; Nishikawa, M.; Oikawa, D.

1988-06-01

340

Towards Ultra-High Resolution Models of Climate and Weather  

SciTech Connect

We present a speculative extrapolation of the performance aspects of an atmospheric general circulation model to ultra-high resolution and describe alternative technological paths to realize integration of such a model in the relatively near future. Due to a superlinear scaling of the computational burden dictated by stability criterion, the solution of the equations of motion dominate the calculation at ultra-high resolutions. From this extrapolation, it is estimated that a credible kilometer scale atmospheric model would require at least a sustained ten petaflop computer to provide scientifically useful climate simulations. Our design study portends an alternate strategy for practical power-efficient implementations of petaflop scale systems. Embedded processor technology could be exploited to tailor a custom machine designed to ultra-high climate model specifications at relatively affordable cost and power considerations. The major conceptual changes required by a kilometer scale climate model are certain to be difficult to implement. Although the hardware, software, and algorithms are all equally critical in conducting ultra-high climate resolution studies, it is likely that the necessary petaflop computing technology will be available in advance of a credible kilometer scale climate model.

Wehner, Michael; Oliker, Leonid; Shalf, John

2007-01-01

341

Adaptive optics with pupil tracking for high resolution retinal imaging.  

PubMed

Adaptive optics, when integrated into retinal imaging systems, compensates for rapidly changing ocular aberrations in real time and results in improved high resolution images that reveal the photoreceptor mosaic. Imaging the retina at high resolution has numerous potential medical applications, and yet for the development of commercial products that can be used in the clinic, the complexity and high cost of the present research systems have to be addressed. We present a new method to control the deformable mirror in real time based on pupil tracking measurements which uses the default camera for the alignment of the eye in the retinal imaging system and requires no extra cost or hardware. We also present the first experiments done with a compact adaptive optics flood illumination fundus camera where it was possible to compensate for the higher order aberrations of a moving model eye and in vivo in real time based on pupil tracking measurements, without the real time contribution of a wavefront sensor. As an outcome of this research, we showed that pupil tracking can be effectively used as a low cost and practical adaptive optics tool for high resolution retinal imaging because eye movements constitute an important part of the ocular wavefront dynamics. PMID:22312577

Sahin, Betul; Lamory, Barbara; Levecq, Xavier; Harms, Fabrice; Dainty, Chris

2012-02-01

342

High Resolution, Real-Time Interferometer for Coherent Beam Combination  

NASA Astrophysics Data System (ADS)

Piston errors introduced during the pumping of high energy amplifiers in the laser chains are estimated to produce significant distortion and dramatically reduce the intensity of the combined beam resulted from the Coherent Beam Combination (CBC) of ultra intense short pulses. For monitoring the phase and optical path shift, we developed a high resolution real time interferometer. Based on the code counting method, the device is suitable for high speed/real time measurements and is immune to vibrations which might appear in the laser system. The device consists of an analog stage which generates the counting code, later processed by the microprocessor unit (CPU). The analog stage ensures 20 nm resolution, 2 m/s optical path variation speed measurements and has low sensitivity to variations of quadrature signals amplitude. The CPU is based on a complex programmable logic device (CPLD), with 8 ns processing time of the signals. The algorithm provides simultaneously measurements with increasing speed for lower resolution (20 nm at 2 m/s, 40 nm at 4 m/s and 80 nm at 8 m/s), making the system fault tolerant at high speed fluctuations of the optical path. The device contains also a digital-to-analog converter stage, making the instrument suitable for implementation of closed loop control.

Simion, Sandel; Blanaru, Constantin; Ursescu, Daniel

2010-04-01

343

High-Resolution Infrared Spectroscopy of Ge_2C_3  

NASA Astrophysics Data System (ADS)

Carbon-rich systems are of great importance in diverse areas of research like material science as well as astro- and structural chemistry. Despite this relevance, our knowledge of smaller cluster units is still fragmentary, particularly with respect to investigations at high-spectral resolution in the gas phase. Unequivocal assignment of spectral features to their molecular carriers is critically dependent on predictions from high-level quantum-chemical calculations. In turn, high-resolution studies provide useful information to assess the predictive power of quantum-chemical methods. This is particularly interesting for cluster systems harboring heavy elements for which so far relatively little is known from experiment. With this contribution, we would like to present a recent gas-phase study of a polyatomic germanium-carbon cluster, linear Ge_2C_3 (Ge=C=C=C=Ge), which was previously studied in an Ar matrix. The cluster was produced through laser ablation of germanium-graphite sample rods and observed in a free jet at wavelengths around 5?m. Additionally, quantum-chemical calculations of Ge_2C_3 were performed at the CCSD(T) level of theory. The production and observation of Ge_2C_3 suggests that many more binary clusters should be amenable to high-resolution spectroscopic techniques not only in the infrared but also in the microwave region. D. L. Robbins, C. M. L. Rittby, and W. R. M. Graham, J. Chem. Phys. 114, 3570 (2001).

Thorwirth, S.; Lutter, V.; Schlemmer, S.; Giesen, T. F.; Gauss, J.

2013-06-01

344

High Resolution Melting Applications for Clinical Laboratory Medicine  

PubMed Central

Separation of the two strands of DNA with heat (melting) is a fundamental property of DNA that is conveniently monitored with fluorescence. Conventional melting is performed after PCR on any real-time instrument to monitor product purity (dsDNA dyes) and sequence (hybridization probes). Recent advances include high-resolution instruments and saturating DNA dyes that distinguish many different species. For example, mutation scanning (identifying heterozygotes) by melting is closed-tube and has similar or superior sensitivity and specificity compared to methods that require physical separation. With high resolution melting, SNPs can be genotyped without probes and more complex regions can be typed with unlabeled hybridization probes. Highly polymorphic HLA loci can be melted to establish sequence identity for transplantation matching. Simultaneous genotyping with one or more unlabeled probes and mutation scanning of the entire amplicon can be performed at the same time in the same tube, vastly decreasing or eliminating the need for re-sequencing in genetic analysis. High-resolution PCR product melting is homogeneous, closed-tube, rapid (15 min), non-destructive and does not require covalently-labeled fluorescent probes. In the clinical laboratory, it is an ideal format for in-house testing, with minimal cost and time requirements for new assay development. PMID:18502416

Erali, Maria; Voelkerding, Karl V.; Wittwer, Carl T.

2008-01-01

345

Multiparameter Flow Cytometry: Advances in High Resolution Analysis  

PubMed Central

Over the past 40 years, flow cytometry has emerged as a leading, application-rich technology that supports high-resolution characterization of individual cells which function in complex cellular networks such as the immune system. This brief overview highlights advances in multiparameter flow cytometric technologies and reagent applications for characterization and functional analysis of cells modulating the immune network. These advances significantly support high-throughput and high-content analyses and enable an integrated understanding of the cellular and molecular interactions that underlie complex biological systems. PMID:23700394

O'Donnell, Erika A; Ernst, David N

2013-01-01

346

High-resolution imaging of the supercritical antisolvent process  

NASA Astrophysics Data System (ADS)

A high-magnification and high-resolution imaging technique was developed for the supercritical fluid antisolvent (SAS) precipitation process. Visualizations of the jet injection, flow patterns, droplets, and particles were obtained in a high-pressure vessel for polylactic acid and budesonide precipitation in supercritical CO2. The results show two regimes for particle production: one where turbulent mixing occurs in gas-like plumes, and another where distinct droplets were observed in the injection. Images are presented to demonstrate the capabilities of the method for examining particle formation theories and for understanding the underlying fluid mechanics, thermodynamics, and mass transport in the SAS process.

Bell, Philip W.; Stephens, Amendi P.; Roberts, Christopher B.; Duke, Steve R.

2005-06-01

347

Proceedings of the 2004 High Spatial Resolution Commercial Imagery Workshop  

NASA Technical Reports Server (NTRS)

Topics covered include: NASA Applied Sciences Program; USGS Land Remote Sensing: Overview; QuickBird System Status and Product Overview; ORBIMAGE Overview; IKONOS 2004 Calibration and Validation Status; OrbView-3 Spatial Characterization; On-Orbit Modulation Transfer Function (MTF) Measurement of QuickBird; Spatial Resolution Characterization for QuickBird Image Products 2003-2004 Season; Image Quality Evaluation of QuickBird Super Resolution and Revisit of IKONOS: Civil and Commercial Application Project (CCAP); On-Orbit System MTF Measurement; QuickBird Post Launch Geopositional Characterization Update; OrbView-3 Geometric Calibration and Geopositional Accuracy; Geopositional Statistical Methods; QuickBird and OrbView-3 Geopositional Accuracy Assessment; Initial On-Orbit Spatial Resolution Characterization of OrbView-3 Panchromatic Images; Laboratory Measurement of Bidirectional Reflectance of Radiometric Tarps; Stennis Space Center Verification and Validation Capabilities; Joint Agency Commercial Imagery Evaluation (JACIE) Team; Adjacency Effects in High Resolution Imagery; Effect of Pulse Width vs. GSD on MTF Estimation; Camera and Sensor Calibration at the USGS; QuickBird Geometric Verification; Comparison of MODTRAN to Heritage-based Results in Vicarious Calibration at University of Arizona; Using Remotely Sensed Imagery to Determine Impervious Surface in Sioux Falls, South Dakota; Estimating Sub-Pixel Proportions of Sagebrush with a Regression Tree; How Do YOU Use the National Land Cover Dataset?; The National Map Hazards Data Distribution System; Recording a Troubled World; What Does This-Have to Do with This?; When Can a Picture Save a Thousand Homes?; InSAR Studies of Alaska Volcanoes; Earth Observing-1 (EO-1) Data Products; Improving Access to the USGS Aerial Film Collections: High Resolution Scanners; Improving Access to the USGS Aerial Film Collections: Phoenix Digitizing System Product Distribution; System and Product Characterization: Issues Approach; Innovative Approaches to Analysis of Lidar Data for the National Map; Changes in Imperviousness near Military Installations; Geopositional Accuracy Evaluations of QuickBird and OrbView-3: Civil and Commercial Applications Project (CCAP); Geometric Accuracy Assessment: OrbView ORTHO Products; QuickBird Radiometric Calibration Update; OrbView-3 Radiometric Calibration; QuickBird Radiometric Characterization; NASA Radiometric Characterization; Establishing and Verifying the Traceability of Remote-Sensing Measurements to International Standards; QuickBird Applications; Airport Mapping and Perpetual Monitoring Using IKONOS; OrbView-3 Relative Accuracy Results and Impacts on Exploitation and Accuracy Improvement; Using Remotely Sensed Imagery to Determine Impervious Surface in Sioux Falls, South Dakota; Applying High-Resolution Satellite Imagery and Remotely Sensed Data to Local Government Applications: Sioux Falls, South Dakota; Automatic Co-Registration of QuickBird Data for Change Detection Applications; Developing Coastal Surface Roughness Maps Using ASTER and QuickBird Data Sources; Automated, Near-Real Time Cloud and Cloud Shadow Detection in High Resolution VNIR Imagery; Science Applications of High Resolution Imagery at the USGS EROS Data Center; Draft Plan for Characterizing Commercial Data Products in Support of Earth Science Research; Atmospheric Correction Prototype Algorithm for High Spatial Resolution Multispectral Earth Observing Imaging Systems; Determining Regional Arctic Tundra Carbon Exchange: A Bottom-Up Approach; Using IKONOS Imagery to Assess Impervious Surface Area, Riparian Buffers and Stream Health in the Mid-Atlantic Region; Commercial Remote Sensing Space Policy Civil Implementation Update; USGS Commercial Remote Sensing Data Contracts (CRSDC); and Commercial Remote Sensing Space Policy (CRSSP): Civil Near-Term Requirements Collection Update.

2006-01-01

348

High-resolution array processing using implicit eigenvector weighting techniques  

SciTech Connect

Many high-resolution bearing estimators require the explicit calculation of the eigenvectors and eigenvalues of the cross-spectral matrix of the sensor outputs. Once the eigenvectors have been calculated, various different estimators can be derived by altering the eigenvalues to give a re-weighing of the eigenvectors. For example, in the MUSIC method the eigenvalues corresponding to those eigenvectors in the noise subspace are set to unity, while the eigenvalues corresponding to those eigenvectors in the signal subspace are set to zero. These weighing functions are reminiscent of ideal filter responses in analog filter theory, where practical filters are designed by using polynomial approximations to the ideal desired response. In this paper, the approximation theory developed for filter design is used to derive high-resolution bearing estimators that do not require explicit calculation of the eigenvectors.

Steele, A.K. (Maritime Systems Div., Weapons Systems Research Lab., Defense Science and Technology Organization, Salisbury, SA 5108 (AU)); Byrne, C.L. (Dept. of Mathematics, Univ. of Lowell, Lowell, MA (US))

1990-01-01

349

Turbine component casting core with high resolution region  

DOEpatents

A hollow turbine engine component with complex internal features can include a first region and a second, high resolution region. The first region can be defined by a first ceramic core piece formed by any conventional process, such as by injection molding or transfer molding. The second region can be defined by a second ceramic core piece formed separately by a method effective to produce high resolution features, such as tomo lithographic molding. The first core piece and the second core piece can be joined by interlocking engagement that once subjected to an intermediate thermal heat treatment process thermally deform to form a three dimensional interlocking joint between the first and second core pieces by allowing thermal creep to irreversibly interlock the first and second core pieces together such that the joint becomes physically locked together providing joint stability through thermal processing.

Kamel, Ahmed; Merrill, Gary B.

2014-08-26

350

HIGH SPATIAL RESOLUTION OBSERVATIONS OF LOOPS IN THE SOLAR CORONA  

SciTech Connect

Understanding how the solar corona is structured is of fundamental importance to determine how the Sun's upper atmosphere is heated to high temperatures. Recent spectroscopic studies have suggested that an instrument with a spatial resolution of 200 km or better is necessary to resolve coronal loops. The High Resolution Coronal Imager (Hi-C) achieved this performance on a rocket flight in 2012 July. We use Hi-C data to measure the Gaussian widths of 91 loops observed in the solar corona and find a distribution that peaks at about 270 km. We also use Atmospheric Imaging Assembly data for a subset of these loops and find temperature distributions that are generally very narrow. These observations provide further evidence that loops in the solar corona are often structured at a scale of several hundred kilometers, well above the spatial scale of many proposed physical mechanisms.

Brooks, David H.; Ugarte-Urra, Ignacio [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Winebarger, Amy R. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States)

2013-08-01

351

High-Resolution Multisensor Infrastructure Inspection with Unmanned Aircraft Systems  

NASA Astrophysics Data System (ADS)

This paper reports on the investigations made at Fraunhofer Institute for Non-Destructive Testing (IZFP) where different rotary wing micro UAS have been used to scan infrastructures including bridges and monuments at high resolutions for remote damage assessment and monitoring purposes. The aerial pictures taken at high speed and frequency have then been stitched together to obtain full 2D and 3D building reconstructions at a resolution allowing damages and cracking to be observed still in the millimeter range. With these ultra hi-res building reconstruction models a specific data base could be created for each object in order to provide extensive information for long term evaluation and life cycle management. The UAS also have been equipped with sensors for damage size estimation, which combined with an image processing software developed to allow automatic cracking pattern recognition could be used for further analysis.

Eschmann, C.; Kuo, C.-M.; Kuo, C.-H.; Boller, C.

2013-08-01

352

High Resolution Scanning Electron Microscopy of Cells Using Dielectrophoresis  

PubMed Central

Ultrastructural analysis of cells can reveal valuable information about their morphological, physiological, and biochemical characteristics. Scanning electron microscopy (SEM) has been widely used to provide high-resolution images from the surface of biological samples. However, samples need to be dehydrated and coated with conductive materials for SEM imaging. Besides, immobilizing non-adherent cells during processing and analysis is challenging and requires complex fixation protocols. In this work, we developed a novel dielectrophoresis based microfluidic platform for interfacing non-adherent cells with high-resolution SEM at low vacuum mode. The system enables rapid immobilization and dehydration of samples without deposition of chemical residues over the cell surface. Moreover, it enables the on-chip chemical stimulation and fixation of immobilized cells with minimum dislodgement. These advantages were demonstrated for comparing the morphological changes of non-budding and budding yeast cells following Lyticase treatment. PMID:25089528

Tang, Shi-Yang; Zhang, Wei; Soffe, Rebecca; Nahavandi, Sofia; Shukla, Ravi; Khoshmanesh, Khashayar

2014-01-01

353

Ultra-high resolution, absolute position sensors for cryostatic applications  

NASA Astrophysics Data System (ADS)

Recent advances in new technology, optical pattern recognition encoders at NASA have resulted in high speed, reliable, compact position sensors for use in cryostatic space flight mechanisms. New encoder scale patterns and image processing algorithms combine with digital signal processors (DSP) and field programmable gate array (FPGA) logic elements to enable encoders with conversion rates in excess of 1.5 kHz (suitable for high speed servo motion control for mechanisms), linear resolutions of less than 10 nm, and angular resolutions in the single digit milli-arcseconds in relatively compact packages. Fiber optic light guides allow encoders to function in cryostats with extremely low power dissipation. Ambient test data for fiber optic configurations suitable for cryogenic environments are presented. Cryostatic test capabilities under development are discussed. Potential applications exist for NGST and other infrared and sub-millimeter missions, such as fine guidance sensing, attitude control, mirror segment position sensing, and mirror scanning.

Leviton, Douglas B.; Frey, Brad

2003-03-01

354

Space to Think: Large, High-Resolution Displays for Sensemaking  

SciTech Connect

Space supports human cognitive abilities in a myriad of ways. The note attached to the side of the monitor, the papers spread out on the desk, diagrams scrawled on a whiteboard, and even the keys left out on the counter are all examples of using space to recall, reveal relationships, and think. Technological advances have made it possible to construct large display environments in which space has real meaning. This paper examines how increased space affects the way displays are regarded and used within the context of the cognitively demanding task of sensemaking. A study was conducted observing analysts using a prototype large, high-resolution display to solve an analytic problem. This paper reports on the results of this study and suggests a number of potential design criteria for future sensemaking tools developed for large, high-resolution displays.

Andrews, Christopher P.; Endert, Alexander; North, Chris

2010-05-05

355

Measuring Large-Scale Social Networks with High Resolution  

PubMed Central

This paper describes the deployment of a large-scale study designed to measure human interactions across a variety of communication channels, with high temporal resolution and spanning multiple yearsthe Copenhagen Networks Study. Specifically, we collect data on face-to-face interactions, telecommunication, social networks, location, and background information (personality, demographics, health, politics) for a densely connected population of 1 000 individuals, using state-of-the-art smartphones as social sensors. Here we provide an overview of the related work and describe the motivation and research agenda driving the study. Additionally, the paper details the data-types measured, and the technical infrastructure in terms of both backend and phone software, as well as an outline of the deployment procedures. We document the participant privacy procedures and their underlying principles. The paper is concluded with early results from data analysis, illustrating the importance of multi-channel high-resolution approach to data collection. PMID:24770359

Stopczynski, Arkadiusz; Sekara, Vedran; Sapiezynski, Piotr; Cuttone, Andrea; Madsen, Mette My; Larsen, Jakob Eg; Lehmann, Sune

2014-01-01

356

High resolution 4-dimension imaging of metanephric embryonic kidney morphogenesis  

PubMed Central

High resolution three-dimensional imaging of fixed embryonic kidney tissues has advanced considerably in the past decade. Here we developed a new process for imaging whole metanephric organ culture at cell resolution in three dimensions over time. This technique combines the use of the newly available generation of infrared optimized long working distance high numerical aperture objectives and multiphoton fluorescence microscopy with a new system for vital staining of metanephric organ cultures with bodipy ceramide. This allows all cells in the organ culture to be visualized over time, enabling detailed observation of tissue morphogenesis. Thus, our method offers a powerful new approach for visualizing and understanding early events in renal development and for extending observations made in genetically manipulated models. PMID:23325081

Clendenon, Sherry G.; Ward, Heather H.; Dunn, Kenneth W.; Bacallao, Robert

2013-01-01

357

High-resolution dot-matrix hologram generation  

NASA Astrophysics Data System (ADS)

Holography is a technique that enables us to permanently record three-dimensional (3D) colour pictures. Owing to their sub-micron structure, holograms are remarkable safety devices that are very difficult to counterfeit. Dot-matrix technology, which is one of the commonly used methods, is a substantial obstacle to all types of fraudulent activities. This kind of hologram is mainly used for the purpose of protection against forgery of cheques, cards, passports, etc. Such a high-resolution technique also enables the engineering of 2D and 3D structures, potentially leading to the construction of metamaterials. In this paper, we describe high-resolution holographic structures obtained by dot-matrix devices of novel construction.

Zarkov, Boban; Gruji?, Duan; Panteli?, Dejan

2012-05-01

358

Airborne laser scanning for high-resolution mapping of Antarctica  

NASA Astrophysics Data System (ADS)

In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

359

Effective Area of the AXAF High Resolution Camera (HRC)  

NASA Technical Reports Server (NTRS)

The AXAF High-Resolution Camera (HRC) was calibrated at NASA MSFC's X-Ray Calibration Facility (XRCF) during 1997 March and April. We have undertaken an analysis of the HRC effective area using all data presently available from the XRCF. We discuss our spectral fitting of the beam-normalization detectors (BNDs), our method of removing higher order contamination lines present in the spectra, and corrections for beam non-uniformities. We apply a model of photon absorption depth in order to fit a smooth curve to the quantum efficiency of the detector. This is then combined with the most recent model of the AXAF High-Resolution Mirror Assembly (HRMA) to determine the ensemble effective area versus energy for the HRC. We also address future goals and concerns.

Patnaude, Daniel; Pease, Deron; Donnelly, Hank; Juda, Mike; Jones, Christine; Murray, Steve; Zombeck, Martin; Kraft, Ralph; Kenter, Almus; Meehan, Gary; Meehan, Gary; Swartz, Doug; Elsner, Ron

1998-01-01

360

High Spatial Resolution Remotely Sensed Data for Ecosystem Characterization  

NSDL National Science Digital Library

This peer-reviewed resource from Bioscience magazine presents technical aspects of remote sensing for images at high spatial resolution. Characterization of ecosystem structure, diversity, and function is increasingly desired at finer spatial and temporal scales than have been derived in the past. Many ecological applications require detailed data representing large spatial extents, but these data are often unavailable or are impractical to gather using field-based techniques. Remote sensing offers an option for collecting data that can represent broad spatial extents with detailed attribute characterizations. Remotely sensed data are also appropriate for use in studies across spatial scales, in conjunction with field-collected data. This article presents the pertinent technical aspects of remote sensing for images at high spatial resolution (i.e., with a pixel size of 16 square meters or less), existing and future options for the processing and analysis of remotely sensed data, and attributes that can be estimated with these data for forest ecosystems.

MICHAEL A. WULDER, RONALD J. HALL, NICHOLAS C. COOPS, and STEVEN E. FRANKLIN (;)

2004-06-01

361

High resolution reservoir geological modelling using outcrop information  

SciTech Connect

This is China`s first case study of high resolution reservoir geological modelling using outcrop information. The key of the modelling process is to build a prototype model and using the model as a geological knowledge bank. Outcrop information used in geological modelling including seven aspects: (1) Determining the reservoir framework pattern by sedimentary depositional system and facies analysis; (2) Horizontal correlation based on the lower and higher stand duration of the paleo-lake level; (3) Determining the model`s direction based on the paleocurrent statistics; (4) Estimating the sandbody communication by photomosaic and profiles; (6) Estimating reservoir properties distribution within sandbody by lithofacies analysis; and (7) Building the reservoir model in sandbody scale by architectural element analysis and 3-D sampling. A high resolution reservoir geological model of Youshashan oil field has been built by using this method.

Zhang Changmin; Lin Kexiang; Liu Huaibo [Jianghan Petroleum Institute, Hubei (China)] [and others

1997-08-01

362

High-speed and high-resolution heterodyne interferometer  

NASA Astrophysics Data System (ADS)

In conventional heterodyne interferometer it Is necessary to provide a high-beat frequency laser when measurement for a high-speed target Is required1 . But use of the high-beat frequency laser makes the " nanometerdivisions" difficult. We have developed a novel interferometer system that has a sufficient response to high-speed movement of the target without Increase of the laser beat frequency. In this work a two frequency laser light passes through the same optical path of the interferometer so that two conjugate beat signals are obtained. By processing the multiple beat signals with a newly developed signal processor the above methodological contradiction is solved. l. OPTICS FOR LINEAR DISTANCE MEASUREMENT Optical system of the interferometer Is shown In Flg. l in which two frequency lights Fl and F2 (freq. f and f2) of orthogonally linear-polarized components of a two mode laser are used. A reference beat signal R (freq. r ) is generated from Fl and F2. Fl and F2 are passed through exactly the same path of the interferometer. A half power of Fl and F2 Is reflected and the rest Is transmitted In the beam splitter ( BS ). Polarization direction of the reflected beam is rotated for ir/2 after passing the X/4 plate twice. The transmitted beam Is reflected by a moving mirror (MM) mounted on the moving target so that frequency of the reflected beam Is shifted by Doppler

Yokoyama, Shuko; Nishihara, I.; Okamoto, A.; Araki, Tsutomu; Suzuki, Norihito

1990-07-01

363

High resolution microwave spectrometer sounder (HIMSS), volume 1, book 1  

NASA Technical Reports Server (NTRS)

The following topics are presented with respect to the high resolution microwave spectrometer sounder (HIMSS) that is to be used as an instrument for NASA's Earth Observing System (EOS): (1) an instrument overview; (2) an instrument description; (3) the instrument's conceptual design; (4) technical risks and offsets; (5) instrument reliability; (6) commands and telemetry; (7) mass and power budgets; (8) integration and test program; (9) program implementation; and (10) phase CD schedule.

1990-01-01

364

A compound representation of high resolution sea clutter  

Microsoft Academic Search

Measurements of sea clutter at low grazing angles using high resolution radar show that the probability density function, p(x), of envelope detected clutter is not Rayleigh. Based on time averaged sea clutter recordings, a compound form of p(x) is proposed leading to the K distribution for the overall p(x). This model is then used to explain both the non Rayleigh

K. D. Ward

1980-01-01

365

High spectral resolution remote sensing of canopy chemistry  

NASA Technical Reports Server (NTRS)

Near infrared laboratory spectra have been used for many years to determine nitrogen and lignin concentrations in plant materials. In recent years, similar high spectral resolution visible and infrared data have been available via airborne remote sensing instruments. Using data from NASA's Airborne visible/Infrared Imaging Spectrometer (AVIRIS) we attempt to identify spectral regions correlated with foliar chemistry at the canopy level in temperate forests.

Aber, John D.; Martin, Mary E.

1995-01-01

366

High-Resolution Inset Head-Mounted Display  

Microsoft Academic Search

A novel approach to inset superimposition in a high-resolution head-mounted display ~HMD! is pre- sented. The approach is innovative in its use of optoelectronic, nonmechanical devices in place of scanning mechanical devices commonly adopted previously. A paraxial layout of the overall HMD system is presented, and the benefit of employing hybrid refractive-diffractive optics for the optical component that generates the

Jannick P. Rolland; Akitoshi Yoshida; Larry D. Davis; John H. Reif

1998-01-01

367

Local structure in perovskite relaxor ferroelectrics: high-resolution 93  

E-print Network

Local structure in perovskite relaxor ferroelectrics: high-resolution 93 Nb 3QMAS NMR Donghua H in capacitors, sensors, actuators, and transduc- ers [1,2]. Most relaxors have ABO3 pseudo-perovskite structure to paraelectric phase transition [4]. In PSN-type perovskites, for example PbSc1=2Ta1=2O3 (PST), the 1:1 long

Vold, Robert

368

A high resolution scintillating fiber gamma-ray-telescope  

Microsoft Academic Search

The design of a large-area gamma-ray detector with high angular and energy resolution for space-based experiments, using scintillating fibers and recently developed position-sensitive photomultiplier tubes, is presented. The structural and functional characteristics of the telescope instruments, a Compton-pair production converter, gas drift time projection chamber (TPC), and calorimeter, are given. It is concluded that with this design the Compton electron

M. Atac; D. B. Cline; E. J. Fenyves; R. C. Chaney

1989-01-01

369

A high resolution analog fiber optics data communications system  

Microsoft Academic Search

A high resolution fiber optics communications system (FOCS) for analog signals has been designed, built, and tested. The system consists of a small transmitter and receiver pair and an optical wave guide. A combination of voltage-to-frequency-to-voltage and pulse width modulation is used to reconstruct a plus or minus 10 volt analog output signal from an identical plus or minus 10

G. J. Grimes; D. R. Stevens

1976-01-01

370

High resolution fiber optic interferometer: FY94 final report  

Microsoft Academic Search

Objective is a field, on-line high resolution spectrometer system capable of resolving the optical emission from actinide isotopes in an inductively coupled plasma. AOTF (acousto-optic tunable filter) and FFP (fiber optic Fabry-Perot) were combined in this spectrometer, using bulk optical materials. The AOTF-FFP system was tested on U-235\\/U-238 and RCRA metals. Future development is described; a commercialization plan is attached.

D. P. Baldwin; D. S. Zamzow

1994-01-01

371

High resolution fiber laser sensor for hydrostatic pressure  

Microsoft Academic Search

Polarimetric fiber laser sensors are attractive due to their frequency encoded output, which does not require any referencing, and their potential for high resolution. Both Fabry-Perot and distributed feedback fiber (DFB) laser sensors have been investigated for the measurement of strain, uniaxial pressure and magnetic fields (H.K. Kim et al, 1993; G.A. Ball et al, 1993; H.K. Kim et al,

A. Frank; K. Haroud; E. Rochat; K. Bohnert; H. Brandle

2002-01-01

372

Enceladus Heat Flow from High Spatial Resolution Thermal Emission Observations  

NASA Astrophysics Data System (ADS)

We estimate the total power radiated from Enceladus' tiger stripes, using Cassini CIRS observations with spatial resolution high enough to separate the active tiger stripe emission from the background. The resulting radiated power, 4.2 GW (to which should be added 0.5 GW of plume latent heat and possible inter-stripe emission), is lower than previous estimates based on the integrated south polar emission, though still higher than expected from steady-state tidal heating.

Spencer, J. R.; Howett, C. J. A.; Verbiscer, A.; Hurford, T. A.; Segura, M.; Spencer, D. C.

2013-09-01

373

High resolution fourier transform infrared spectrum of difluoroethyne, FCCF.  

NASA Astrophysics Data System (ADS)

Difluoroethyne, monitored by FTIR spectroscopy, has been prepared in the vapour phase by vacuum pyrolysis and photolysis of difluoromaleic anhydride and pyrolysis of 3-bromo-3,3-difluoropropanoic trifluoroacetic anhydride. The infrared spectrum of difluoroethyne has been assigned at both low and high resolution and wavenumber values for all five fundamentals estimated. Difluoropropadienone was observed as a pyrolysis product and difluorocyclopropenone as a photolysis product.

McNaughton, Don; Elmes, Patricia

1992-04-01

374

High-resolution sonography of the abnormal cranial suture  

Microsoft Academic Search

Objective. The purpose of this investigation is to elucidate the sonographic features of abnormal major cranial sutures. Materials and methods. Eight excised synostosed suture specimens were evaluated. The high-resolution sonographic appearance was correlated with\\u000a the histological section, plain radiographs, CT and MRI. Diastatic and molded sutures were also evaluated with sonography\\u000a and compared with the normal cranial suture appearance. Results.

Don Soboleski; Ben Mussari; Deb McCloskey; Eric Sauerbrei; Franco Espinosa; Al Fletcher

1998-01-01

375

GEOMETRIC VALIDATION OF TERRASAR-X HIGH-RESOLUTION PRODUCTS  

Microsoft Academic Search

Switzerland's diversity of flat, rolling and Alpine terrain makes it ideal territory for geometric validation studies. We describe here two parallel investigations of TerraSAR-X (TSX) high-resolution data: geometric validation and estimation of the tropospheric path delay using measurements of corner reflectors (CRs) placed at different altitudes but nearly identical ranges. Geometric validation was conducted using products from the spotlight and

Adrian Schubert; Michael Jehle; David Small; Erich Meier

376

Evaluating high resolution SPOT 5 satellite imagery for crop identification  

Microsoft Academic Search

High resolution satellite imagery offers new opportunities for crop monitoring and assessment. A SPOT 5 image acquired in May 2006 with four spectral bands (green, red, near-infrared, and short-wave infrared) and 10-m pixel size covering intensively cropped areas in south Texas was evaluated for crop identification. Two images with pixel sizes of 20m and 30m were also generated from the

Chenghai Yang; James H. Everitt; Dale Murden

2011-01-01

377

Need for high resolution in VUV Rydberg state spectroscopy  

NASA Technical Reports Server (NTRS)

The paper emphasizes the necessity of high energy resolution (resolving powers greater than 100,000) in VUV spectroscopic determinations of atomic and molecular Rydberg electronic structures. Attention is given to spectral observations of Rydberg levels in Ge I near the 4p 2P(0)1/2 limit, in Sr I near the 4d 2D3/2 limit, and in diatomic hydrogen halides (especially H I) below the X2Pi3/2 limit.

Ginter, M. L.; Ginter, D. S.; Brown, C. M.

1980-01-01

378

Pointed telescope subassembly for the UARS High Resolution Doppler Imager  

NASA Technical Reports Server (NTRS)

The Pointed Telescope Subassembly (PTS) consists of a telescope, its Coude relay optics, a two axis gimbal mechanism, and a cover/caging device. These components, their mechanisms, the requirements, and some of the trade-offs leading to the final design are described. The PTS supplies light to the interferometer of the High Resolution Doppler Imager to be used to study upper atmospheric wind velocity.

Renken, Robert D.

1987-01-01

379

High-Resolution, Real-time 3D Shape Acquisition  

Microsoft Academic Search

In this paper we describe a high-resolution, real-time 3D shape acquisition system based on structured light techniques. This system uses a color pattern whose RGB channels are coded with either sinusoidal or trapezoidal fringe patterns. When projected by a modified DLP projector (color filters removed), this color pattern results in three grayscale patterns projected sequentially at a frequency of 240

Song Zhang; Peisen Huang

2004-01-01

380

High-Resolution Wind Measurements for Offshore Wind Energy Development  

NASA Technical Reports Server (NTRS)

A mathematical transform, called the Rosette Transform, together with a new method, called the Dense Sampling Method, have been developed. The Rosette Transform is invented to apply to both the mean part and the fluctuating part of a targeted radar signature using the Dense Sampling Method to construct the data in a high-resolution grid at 1-km posting for wind measurements over water surfaces such as oceans or lakes.

Nghiem, Son V.; Neumann, Gregory

2011-01-01

381

High-resolution structure of hair-cell tip links  

Microsoft Academic Search

Transduction-channel gating by hair cells apparently requires a gating spring, an elastic element that transmits force to the channels. To determine whether the gating spring is the tip link, a filament interconnecting two stereocilia along the axis of mechanical sensitivity, we examined the tip link's structure at high resolution by using rapid-freeze, deep-etch electron microscopy. We found that the tip

Bechara Kachar; Marianne Parakkal; Mauricio Kurc; Yi-Dong Zhao; Peter G. Gillespie

2000-01-01

382

HRSC: the High Resolution Stereo Camera of Mars Express  

Microsoft Academic Search

The High Resolution Stereo Camera (HRSC), originally developed for the Russian-led Mars-96 mission, was selected as part of the Orbiter payload for ESA's Mars Express mission. The HRSC is a pushbroom scanning instrument with nine CCD line detectors mounted in parallel in the focal plane. Its unique feature is the ability to obtain near-simultaneous imaging data of a specific site

G. Neukum; R. Jaumann

2004-01-01

383

Performance of the WIYN high-resolution infrared camera  

Microsoft Academic Search

The WIYN High Resolution Infrared Camera (WHIRC) has been a general-use instrument at the WIYN telescope on Kitt Peak since 2008. WHIRC is a near-infrared (0.8 - 2.5 mum) camera with a filter complement of J, H, Ks broadband and 10 narrowband filters, utilizing a 2048 2048 HgCdTe array from Raytheon's VIRGO line, developed for the VISTA project. The

Margaret Meixner; Stephen Smee; Ryan L. Doering; Robert H. Barkhouser; Todd Miller; Joseph Orndorff; Patricia Knezek; Edward Churchwell; Gregg Scharfstein; Jeffrey Percival; David Mills; Charles Corson; Richard Joyce; Brian Ferguson; Masaaki Otsuka

2010-01-01

384

Amorphous Silicon as Semiconductor Material for High Resolution LAPS  

E-print Network

Amorphous Silicon as Semiconductor Material for High Resolution LAPS Werner Moritz1 , Tatsuo-insulator- semiconductor (MIS) structures based on amorphous silicon (a-Si) prepared as a thin layer on transparent glass-substrate Amorphous silicon -4 -2 0 2 4 0,2 0,4 0,6 0,8 1,0 photocurrenta.u. gate voltage/V 600µm x 600µm area scan

Moritz, Werner

385

Spectral analysis of high resolution temperature profiles in the stratosphere  

SciTech Connect

The authors present in this paper one of the first high resolution analysis of temperature profiles measured in the lower stratosphere. The temperature fluctuations level is shown to depend only on the static stability. Moreover, in the 12-1,500 m vertical wavelength range, the temperature spectrum has a mean slope around - 2.3, a value significantly above the - 3 saturated model value.

Cot, C.; Barat, J. (Service d' Aeronomie du CNRS, Verrieres le Buisson (France))

1989-10-01

386

High-resolution optical imaging of the 'Frosty Leo' nebula  

NASA Technical Reports Server (NTRS)

High-resolution optical images have been obtained of IRAS 09371 + 1212 (the 'Frosty Leo' nebula). The images were taken with the Dominion Astrophysical Observatory/Canada-France-Hawaii Telescope (DAO/CFHT) High-Resolution Camera using broadband V and I filters and with an intermediate-band H-alpha filter. The red filters, particularly H-alpha show that the bipolar nebula is surrounded by a nearly spherical envelope of material approximately 30 sec in diameter. The high-resolution images allow a detailed study of changes in the nebular morphology with wavelength. The ansae remain stationary with wavelength, whereas the positions of the lobes and the position angle of the disk change with wavelength from the optical to the near infrared. These results suggest that the ejection process is colliminated by the disk, which has been processing with time. The possibility that the Frosty Leo nebula is not a post-asymptotic giant branch (AGB) star but a pre-main-sequence object formed in isolation from interstellar clouds is discussed.

Langill, Philip P.; Kwok, Sun; Hrivnak, Bruce J.

1994-01-01

387

High resolution ultrasonic spectroscopy system for nondestructive evaluation  

NASA Technical Reports Server (NTRS)

With increased demand for high resolution ultrasonic evaluation, computer based systems or work stations become essential. The ultrasonic spectroscopy method of nondestructive evaluation (NDE) was used to develop a high resolution ultrasonic inspection system supported by modern signal processing, pattern recognition, and neural network technologies. The basic system which was completed consists of a 386/20 MHz PC (IBM AT compatible), a pulser/receiver, a digital oscilloscope with serial and parallel communications to the computer, an immersion tank with motor control of X-Y axis movement, and the supporting software package, IUNDE, for interactive ultrasonic evaluation. Although the hardware components are commercially available, the software development is entirely original. By integrating signal processing, pattern recognition, maximum entropy spectral analysis, and artificial neural network functions into the system, many NDE tasks can be performed. The high resolution graphics capability provides visualization of complex NDE problems. The phase 3 efforts involve intensive marketing of the software package and collaborative work with industrial sectors.

Chen, C. H.

1991-01-01

388

Quantification of Murine Pancreatic Tumors by High Resolution Ultrasound  

PubMed Central

Summary Ultrasonography is a powerful imaging modality that enables non-invasive, real time visualization of abdominal organs and tissues. This technology may be adapted for use in mice through the utilization of higher frequency transducers, allowing for extremely high resolution imaging of the mouse pancreas. This technique is particularly well-suited to pancreas imaging due to the ultrasonographic properties of the normal mouse pancreas, easily accessible imaging planes for the head and tail of the mouse pancreas, and the comparative difficulty in imaging the mouse pancreas with other technologies. A suite of measurements tools is available to characterize the normal and diseased states of tissues. Of particular utility for cancer applications is the ability to use tomography to construct a 3D tumor volume, enabling longitudinal imaging studies to track tumor development, or response to therapies. Here, we describe a detailed method for performing high resolution ultrasound to detect and measure pancreatic lesions in a genetically engineered mouse model of pancreatic ductal using the VisualSonics Vevo2100 High Resolution Ultrasound System. The method includes preparation of the animal for imaging, 2D and 3D image acquisition, and post-acquisition analysis of tumors volumes. The combined procedure has been utilized extensively by our group and others for the preclinical evaluation of novel therapeutic agents in the treatment of pancreatic ductal adenocarcinoma (14). PMID:23359158

Sastra, Stephen A.; Olive, Kenneth P.

2013-01-01

389

High Resolution Cluster Pressure Profile Measurements with MUSTANG and Bolocam  

NASA Astrophysics Data System (ADS)

Accurate high-resolution intracluster medium (ICM) pressure profiles will help further constrain cosmological parameters as well as baryonic physics in the cores of clusters of galaxies. MUSTANG, a 90 GHz bolometer array on the Green Bank Telescope (GBT) is among the highest resolution (9' FWHM) instruments at 90 GHz, and is among the best instruments to observe the ICM given its sensitivity. We present results from a sub-sample of the Cluster Lensing And Supernova with Hubble (CLASH) clusters of galaxies observed with both MUSTANG and Bolocam. Bolocam, a 150 GHz bolometer array on the CSO with 58' FWHM, and MUSTANG data probe different, and highly complementary, angular (size) scales. We jointly fit spherical electron pressure profiles to the two datasets and find that the addition of the high resolution MUSTANG data can considerably improve constraints on the pressure profiles. A major asset of our fitting algorithm is the ability to uniquely fit for contaminants such as point sources, and thus allowing us to determine the signal from the underlying ICM. We compare our best fit profiles to X-ray determined pressure profiles (provided by ACCEPT), where we find good agreement. Finally we investigate the implications of our results and describe ongoing work to extend this analysis to the full set of CLASH clusters viewable by the GBT, and to obtain even better results with the MUSTANG-1.5 camera

Romero, Charles; Mason, Brian S.; Sayers, Jack; Young, Alexander; Dicker, Simon; Mroczkowski, Tony; Reese, Erik D.; Sarazin, Craig L.; Czakon, Nicole G.; Devlin, Mark J.; Korngut, Phillip

2015-01-01

390

Regional High Resolution Reanalysis Covered European North East Shelf  

NASA Astrophysics Data System (ADS)

Mercator-Ocean has developed a regional forecasting system at 1/12 resolution over the North East Atlantic (IBI: Iberia, Biscay and Irish), taking advantage of the recent developments in NEMO. This regional forecasting system uses boundary conditions from the Mercator-Ocean global reanalysis (GLORYS: Global Ocean ReanalYses and Simulations). The assimilation component of the Mercator Ocean system, is based on a reduced-order Kalman filter (the SEEK or Singular Extended Evolutive Kalman filter). An IAU method (Incremental Analysis Updates) is used to apply the increments in the system. The error statistics are represented in a sub-space spanned by a small number of dominant 3D error directions. The data assimilation system allows to constrain the model in a multivariate way with Sea Surface Temperature (AVHRR + Multi-satellite High resolution), together with all available satellite Sea Level Anomalies, and with in situ observations from the CORA-03 data base, including ARGO floats temperature and salinity measurements. This reanalysis covers the period from January 2002 to December 2009. In this presentation, the results obtained with this reanalysis system (1/12) are compared to the GLORYS ones. A special focus will be made on the gain thanks to the higher resolution of the model and higher resolution of the SST assimilated in this reanalysis.

Bourdalle-Badie, R.; Benkiran, M.; Chanut, J.; Drillet, Y.; Reffray, G.

2011-12-01

391

High energy resolution, high angular acceptance crystal monochromator  

DOEpatents

A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut ({alpha}=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5--30 keV) of synchrotron radiation down to the {micro}eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator. 7 figs.

Alp, E.E.; Mooney, T.M.; Toellner, T.

1996-06-04

392

Analyzing Multi-Fiber Reconstruction in High Angular Resolution Diffusion Imaging using the Tensor Distribution Function  

E-print Network

Analyzing Multi-Fiber Reconstruction in High Angular Resolution Diffusion Imaging using the Tensor. Index Terms-- High Angular Resolution Diffusion Imaging, Tensor Distribution Function, multi-fiber protocols with higher angular and radial resolutions, such as the high- angular resolution diffusion imaging

Thompson, Paul

393

High-resolution free-electron laser spectroscopy  

SciTech Connect

The broad and continuous turnability of the rf linac-driven free-electron laser (FEL), coupled with its high power picosecond time structure, has greatly enhanced the research capabilities in the field of infrared spectroscopy. However, the duration of the optical pulses is often too long to probe ultrafast processes, and the spectral structure of the optical beam, with closely spaced longitudinal modes in a bandwidth determined by the Fourier transform of the short pulses, poses a significant limitation for experiments requiring high spectral resolution. The temporal resolution can be improved by operating the FEL with electron pulses whose energy varies linearly with time; the resulting optical pulses possess substantial frequency chirps and are susceptible to pulse compression in an external dispersive delay line. The spectral resolution can be enhanced by using an intracavity Michelson interferometer to couple successive optical pulses so that they build up from noise with a definite phase relationship; the longitudinal modes in the output beam are then separated by the rf frequency of the linac and can be individually filtered for applications in high resolution spectroscopy. This dissertation develops small signal analyses for each of these modes of operation, and reports the results of numerical pulse propagation simulations whose parameters were chosen to guide the design of feasible experiments on the Mark III FEL. Chirp-pulse simulations using modest energy chirps have demonstrated a x15 compression ratio at saturated power levels for 3.4 ps optical pulses at 3.35 [mu]m, and coupled pulse simulations have indicated substantial longitudinal mode reduction on microsecond time scales. The author also developed a derivation of FEL coupled mode equations using conventional mode locked laser theory, and solved them numerically in the frequency domain. Finally, the author reports the first operation of a Michelson mirror resonator on the Mark III FEL.

Szarmes, E.B.

1992-01-01

394

Operation Castle. Project 18. 3. High-resolution spectroscopy  

SciTech Connect

The high-resolution work undertaken at Castle with three spectrographs of relatively high dispersion is described and analyzed. Profitable results were obtained from the spectra taken with the JACO 21-foot Wadsworth-mount spectrograph, mainly the highest violet cutoff to date and a very predominant NO/sub 2/ spectrum in absorption. There is a definite indication that the NO/sub 2/ exists in a state of excitation above that observed at ordinary room temperature. The observation as a function of time of the formation NO/sub 2/, which conceivably can be formed in different ways during different intervals of the explosion, would be of great interest.

Beck, C.A.; Campbell, J.H.

1985-09-01

395

High resolution upgrade of the ATF damping ring BPM system  

SciTech Connect

A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility (ATF) damping ring has been accomplished in its first stage, carried out by a KEK/FNAL/SLAC collaboration under the umbrella of the global ILC R&D effort. The upgrade consists of a high resolution, high reproducibility read-out system, based on analog and digital downconversion techniques, digital signal processing, and also tests a new automatic gain error correction schema. The technical concept and realization, as well as preliminary results of beam studies are presented.

Terunuma, N.; Urakawa, J.; /KEK, Tsukuba; Frisch, J.; May, J.; McCormick, D.; Nelson, J.; Seryi, A.; Smith, T.; Woodley, M.; /SLAC; Briegel, C.; Dysert, R.; /Fermilab

2008-05-01

396

High-Resolution and Animal Imaging Instrumentation and Techniques  

NASA Astrophysics Data System (ADS)

During the last decade we have observed a growing interest in "in vivo" imaging techniques for small animals. This is due to the necessity of studying biochemical processes at a molecular level for pharmacology, genetic, and pathology investigations. This field of research is usually called "molecular imaging."Advances in biological understanding have been accompanied by technological advances in instrumentation and techniques and image-reconstruction software, resulting in improved image quality, visibility, and interpretation. The main technological challenge is then the design of systems with high spatial resolution and high sensitivity.

Belcari, Nicola; Guerra, AlbertoDel

397

High-Resolution Protein Structure Determination by Serial Femtosecond Crystallography  

PubMed Central

Structure determination of proteins and other macromolecules has historically required the growth of high-quality crystals sufficiently large to diffract x-rays efficiently while withstanding radiation damage. We applied serial femtosecond crystallography (SFX) using an x-ray free-electron laser (XFEL) to obtain high-resolution structural information from microcrystals (less than 1 micrometer by 1 micrometer by 3 micrometers) of the well-characterized model protein lysozyme. The agreement with synchrotron data demonstrates the immediate relevance of SFX for analyzing the structure of the large group of difficult-to-crystallize molecules. PMID:22653729

Boutet, Sbastien; Lomb, Lukas; Williams, Garth J.; Barends, Thomas R. M.; Aquila, Andrew; Doak, R. Bruce; Weierstall, Uwe; DePonte, Daniel P.; Steinbrener, Jan; Shoeman, Robert L.; Messerschmidt, Marc; Barty, Anton; White, Thomas A.; Kassemeyer, Stephan; Kirian, Richard A.; Seibert, M. Marvin; Montanez, Paul A.; Kenney, Chris; Herbst, Ryan; Hart, Philip; Pines, Jack; Haller, Gunther; Gruner, Sol M.; Philipp, Hugh T.; Tate, Mark W.; Hromalik, Marianne; Koerner, Lucas J.; van Bakel, Niels; Morse, John; Ghonsalves, Wilfred; Arnlund, David; Bogan, Michael J.; Caleman, Carl; Fromme, Raimund; Hampton, Christina Y.; Hunter, Mark S.; Johansson, Linda C.; Katona, Gergely; Kupitz, Christopher; Liang, Mengning; Martin, Andrew V.; Nass, Karol; Redecke, Lars; Stellato, Francesco; Timneanu, Nicusor; Wang, Dingjie; Zatsepin, Nadia A.; Schafer, Donald; Defever, James; Neutze, Richard; Fromme, Petra; Spence, John C. H.; Chapman, Henry N.; Schlichting, Ilme

2013-01-01

398

High Resolution Continuous Flow Analysis System for Polar Ice Cores  

NASA Astrophysics Data System (ADS)

In the last decades, Continuous Flow Analysis (CFA) technology for ice core analyses has been developed to reconstruct the past changes of the climate system 1), 2). Compared with traditional analyses of discrete samples, a CFA system offers much faster and higher depth resolution analyses. It also generates a decontaminated sample stream without time-consuming sample processing procedure by using the inner area of an ice-core sample.. The CFA system that we have been developing is currently able to continuously measure stable water isotopes 3) and electrolytic conductivity, as well as to collect discrete samples for the both inner and outer areas with variable depth resolutions. Chemistry analyses4) and methane-gas analysis 5) are planned to be added using the continuous water stream system 5). In order to optimize the resolution of the current system with minimal sample volumes necessary for different analyses, our CFA system typically melts an ice core at 1.6 cm/min. Instead of using a wire position encoder with typical 1mm positioning resolution 6), we decided to use a high-accuracy CCD Laser displacement sensor (LKG-G505, Keyence). At the 1.6 cm/min melt rate, the positioning resolution was increased to 0.27mm. Also, the mixing volume that occurs in our open split debubbler is regulated using its weight. The overflow pumping rate is smoothly PID controlled to maintain the weight as low as possible, while keeping a safety buffer of water to avoid air bubbles downstream. To evaluate the system's depth-resolution, we will present the preliminary data of electrolytic conductivity obtained by melting 12 bags of the North Greenland Eemian Ice Drilling (NEEM) ice core. The samples correspond to different climate intervals (Greenland Stadial 21, 22, Greenland Stadial 5, Greenland Interstadial 5, Greenland Interstadial 7, Greenland Stadial 8). We will present results for the Greenland Stadial -8, whose depths and ages are between 1723.7 and 1724.8 meters, and 35.520 to 35.636 kyr b2k 7), respectively. The results show the conductivity measured upstream and downstream of the debubbler. We will calculate the depth resolution of our system and compare it with earlier studies. 1) Bigler at al, "Optimization of High-Resolution Continuous Flow Analysis For Transient Climate Signals in Ice Cores". Environ. Sci. Technol. 2011, 45, 4483-4489 2) Kaufmann et al, "An Improved Continuous Flow Analysis System for High Resolution Field Measurements on Ice Cores". Environmental Environ. Sci. Technol. 2008, 42, 8044-8050 3) Gkinis, V., T. J. Popp, S. J. Johnsen and T, Blunier, 2010: A continuous stream flash evaporator for the calibration of an IR cavity ring down spectrometer for the isotopic analysis of water. Isotopes in Environmental and Health Studies, 46(4), 463-475. 4) McConnell et al, "Continuous ice-core chemical analyses using inductively coupled plasma mass spectrometry. Environ. Sci. Technol. 2002, 36, 7-11 5) Rhodes et al, "Continuous methane measurements from a late Holocene Greenland ice core : Atmospheric and in-situ signals" Earth and Planetary Science Letters. 2013, 368, 9-19 6) Breton et al, "Quantifying Signal Dispersion in a Hybrid Ice Core Melting System". Environ. Sci. Technol. 2012, 46, 11922-11928 7) Rasmussen et al, " A first chronology for the NEEM ice core". Climate of the Past. 2013, 9, 2967--3013

Dallmayr, Remi; Azuma, Kumiko; Yamada, Hironobu; Kjr, Helle Astrid; Vallelonga, Paul; Azuma, Nobuhiko; Takata, Morimasa

2014-05-01

399

Spatial-temperature high resolution map for early cancer diagnosis  

NASA Astrophysics Data System (ADS)

Heat is one of the most important parameters of living beings. Skin temperature is not the same on the entire body and so, a thermal signature can be got. Infrared map on serial imaging can constitute an early sign of an abnormality. Thermography detects changes in tissue that appear before and accompany many diseases including cancer. As this map has a better resolution an early cancer diagnosis can be done. The temperature of neoplasic tissue is different up to 1.5 C than that of the healthy tissue as a result of the specific metabolic rate. The infrared camera images show very quickly the heat transferred by radiation. A lot of factors disturb the temperature conversion to pixel intensity. A sensitive temperature sensor with a 10 Mpixels video camera, showing its spatial position, and a computer fusion program were used for the map with high spatial-temperature resolution. A couple of minutes are necessary to get a high resolution map. The asymmetry and borders were the main parameters analyzed. The right cancer diagnosis was for about 78.4% of patients with thyroid cancer, and more than 89.6% from patients with breast cancer. In the near future, the medical prognosis will be improved by fractal analysis.

Gavriloaia, Gheorghe V.; Hurduc, Anca; Ghimigean, Ana-Maria; Fumarel, Radu

2009-02-01

400

High-resolution manometry changes our views of gastrointestinal motility.  

PubMed

High-resolution manometry using catheters with 36 solid-state sensors spaced 1cm apart has already become an established technique for esophageal manometry where it has replaced water-perfused and station pull-through manometry. Spatiotemporal plots with color coding of pressure have greatly facilitated the analysis of esophageal peristalsis. Although suitable for the length of the esophagus, the solid-state catheter is insufficient for the study of longer segments of the gastrointestinal tract. A new technique with fiber-optic sensors has made it possible to construct catheters with 72-144 sensors. Studies of colonic motility have revealed that the most common motor pattern of the colon is a peristaltic contraction that travels 7-10cm in the retrograde direction. Earlier studies using low-resolution manometry with 7-45cm between sensors led us to erroneous conclusions regarding direction and frequency of contractions and they largely missed both antegrade and retrograde contractions traveling short distances. Fiber-optic high-resolution manometry holds promise for greatly improving our understanding of gut motor physiology and hopefully also our understanding of patients with symptoms of disordered gut motility. PMID:24073826

Lindberg, G

2013-10-01

401

A New Thermal Method for High-resolution Aquifer Characterization  

NASA Astrophysics Data System (ADS)

Spatial variations in flow and transport properties play an important role in solute movement in aquifer systems. A major challenge has been to develop field methods that allow information about these variations to be obtained at the resolution needed to characterize transport in heterogeneous formations. Recently, we have developed a new thermal method that holds considerable promise for obtaining high-resolution information about aquifer structure and, potentially, groundwater flux in an efficient fashion. This new approach, which is based on Raman scattering distributed temperature sensing along fiber optic cables deployed below the water table, was applied to a field site located in the floodplain of the Kansas River in the central United States. Results indicate that the temperature profiles obtained using this method are remarkably consistent with hydraulic conductivity (K) estimates obtained through other means at the same location and provide new insights into the factors controlling the relatively large K variations observed within the sand and gravel aquifer at this site. The temperature profiles were significantly changed when a nearby pump was turned on, particularly in the vicinity of the vertical interval of the pump intake, demonstrating the convergence of groundwater flow on the pump intake. The high resolution possible with distributed temperature sensing enables this new method to provide a more detailed representation of aquifer dynamics and structure than previous approaches.

Liu, G.; Knobbe, S.; Butler, J. J.; Reboulet, E. C.

2011-12-01

402

Live CLEM Imaging to Analyze Nuclear Structures at High Resolution.  

PubMed

Fluorescence microscopy (FM) and electron microscopy (EM) are powerful tools for observing molecular components in cells. FM can provide temporal information about cellular proteins and structures in living cells. EM provides nanometer resolution images of cellular structures in fixed cells. We have combined FM and EM to develop a new method of correlative light and electron microscopy (CLEM), called "Live CLEM." In this method, the dynamic behavior of specific molecules of interest is first observed in living cells using fluorescence microscopy (FM) and then cellular structures in the same cell are observed using electron microscopy (EM). Following image acquisition, FM and EM images are compared to enable the fluorescent images to be correlated with the high-resolution images of cellular structures obtained using EM. As this method enables analysis of dynamic events involving specific molecules of interest in the context of specific cellular structures at high resolution, it is useful for the study of nuclear structures including nuclear bodies. Here we describe Live CLEM that can be applied to the study of nuclear structures in mammalian cells. PMID:25555577

Haraguchi, Tokuko; Osakada, Hiroko; Koujin, Takako

2015-01-01

403

High-resolution tomographic interferometry of optical phase elements  

NASA Astrophysics Data System (ADS)

Decades ago tomographic interferometry was successfully applied to the measurement of phase objects in a large scale. Recently the application field was extended to nearly micro scale, for example optical fibers. Nevertheless, the geometry of tested objects was usually relatively simple and the spatial resolution at the level of several microns was always a barrier. In this paper we investigate the possibility of tomographic reconstruction of complex phase objects by means of tomographic interferometry. The analyses have been performed on the photonic crystal fiber, which is not only a high-resolution object, but additionally contains periodic structures. The influences of the following factors are investigated: proper matching of the immersion liquid, mechanical imperfections of the rotation, geometry of the fiber, polarization of the illumination beam and type of reconstruction algorithm. In addition to experimental results, the numerical simulation of wavefront propagation through the fiber is performed. According to the results, the high - resolution reconstruction of the three-dimensional refractive index distribution in the object containing a periodic structure is possible, however limited by several conditions, as described in the paper.

Gorski, W.; Rafler, S.; Osten, W.

2007-06-01

404

Carbonic Anhydrase and Osteoclasts: Localization by Labeled Inhibitor Autoradiography  

Microsoft Academic Search

Autoradiography with tritiated acetazolamide indicates that osteoclasts of the hen and chick contain concentrations of carbonic anhydrase which are similar to those in pancreatic acinar cells. Grain counts of osteoblasts and osteocytes were not different from background. Thus, a sufficient quantity of carbonic anhydrase seems to be present in osteoclasts to be of physiological importance in bone resorption.

Carol V. Gay; Werner J. Mueller

1974-01-01

405

Nanogate - A Nanosecond Gated Image Intensifier with High Gain and High Resolution  

Microsoft Academic Search

The investigation of luminous phenomena with two-dimensional resolution in space and resolution in time requires electro-optical devices which can be gated for very short time intervals. Image intensifiers are presently mainly used for this purpose. They are available either as image intensifiers with microchannel plates or as image intensifier diodes. Due to secondary electron multiplication, microchannel plate intensifiers have high

W. Pfeiffer; D. Wittmer

1984-01-01

406

High-Resolution, Wide-Field-of-View Scanning Telescope  

NASA Technical Reports Server (NTRS)

A proposed telescope would afford high resolution over a narrow field of view (<0.10 ) while scanning over a total field of view nominally 16 wide without need to slew the entire massive telescope structure. The telescope design enables resolution of a 1-m-wide object in a 50- km-wide area of the surface of the Earth as part of a 200-km-wide area field of view monitored from an orbit at an altitude of 700 km. The conceptual design of this telescope could also be adapted to other applications both terrestrial and extraterrestrial in which there are requirements for telescopes that afford both wide- and narrow-field capabilities. In the proposed telescope, the scanning would be effected according to a principle similar to that of the Arecibo radio telescope, in which the primary mirror is stationary with respect to the ground and a receiver is moved across the focal surface of the primary mirror. The proposed telescope would comprise (1) a large spherical primary mirror that would afford high resolution over a narrow field of view and (2) a small displaceable optical relay segment that would be pivoted about the center of an aperture stop to effect the required scanning (see figure). Taken together, both comprise a scanning narrow-angle telescope that does not require slewing the telescope structure. In normal operation, the massive telescope structure would stare at a fixed location on the ground. The inner moveable relay optic would be pivoted to scan the narrower field of view over the wider one, making it possible to retain a fixed telescope orientation, while obtaining high-resolution images over multiple target areas during an interval of 3 to 4 minutes in the intended orbit. The pivoting relay segment of the narrow-angle telescope would include refractive and reflective optical elements, including two aspherical mirrors, to counteract the spherical aberration of the primary mirror. Overall, the combination of the primary mirror and the smaller relay optic would provide narrow-angle, diffraction-limited high resolution at a wavelength of 500 nm.

Sepulveda, Cesar; Wilson, Robert; Seshadri, Suresh

2007-01-01

407

High-resolution ultrasound imaging of the eye a review  

PubMed Central

This report summarizes the physics, technology and clinical application of ultrasound biomicroscopy (UBM) of the eye, in which frequencies of 35 MHz and above provide over a threefold improvement in resolution compared with conventional ophthalmic ultrasound systems. UBM allows imaging of anatomy and pathology involving the anterior segment, including regions obscured by overlying optically opaque anatomic or pathologic structures. UBM provides diagnostically significant information in conditions such as glaucoma, cysts and neoplasms, trauma and foreign bodies. UBM also can provide crucial biometric information regarding anterior segment structures, including the cornea and its constituent layers and the anterior and posterior chambers. Although UBM has now been in use for over 15 years, new technologies, including transducer arrays, pulse encoding and combination of ultrasound with light, offer the potential for significant advances in high-resolution diagnostic imaging of the eye. PMID:19138310

Silverman, Ronald H

2009-01-01

408

High-resolution microendoscope for the detection of cervical neoplasia.  

PubMed

Cervical cancer causes 275,000 deaths each year with 85 % of these deaths occurring in the developing world. One of the primary reasons for the concentration of deaths in developing countries is a lack of effective screening methods suited for the infrastructure of these countries. In order to address this need, we have developed a high-resolution microendoscope (HRME). The HRME is a fiber-based fluorescence microscope with subcellular resolution. Using the vital stain proflavine, we are able to image cell nuclei in vivo and evaluate metrics such as nuclear-to-cytoplasmic ratio, critical to identifying precancerous epithelial regions. In this chapter, we detail the materials and methods necessary to build this system from commercially available parts. PMID:25626555

Grant, Benjamin D; Schwarz, Richard A; Quang, Timothy; Schmeler, Kathleen M; Richards-Kortum, Rebecca

2015-01-01

409

Novolak resin design concept for high-resolution positive resists  

NASA Astrophysics Data System (ADS)

A new novolak-type photoresist which is applicable to excimer laser lithography has been developed. This resist consists of a naphthoquinonediazide-4-sulfonyl ester(NQD-4) and branched novolak resins, which are synthesized in an excess formalin/m-cresol molar ratio (1approximately equals 2) condition. The branched novolak resin-NQD-4 pendent resist (BNP resist) has about two times higher sensitivity than a conventional novolak resist (PR-1024MB) and exhibits clearly a surface development induction, which affords higher (gamma) -values. Copolymerization of hydroquinone (HQ) improves the sensitivity, resist profile, and mask linearity of the BNP resist. The BNP-HQ resist has a resolution capability of 0.35 micrometers lines and spaces with a KrF excimer laser sensitivity of about 170 mJ/cm2. Therefore, our design concept of novolak resin is applicable to high resolution positive resists and especially to excimer resists.

Noguchi, Tsutomu; Tomita, Hidemi

1991-06-01

410

A high resolution spectrometer for EUV/FUV wavelengths  

NASA Astrophysics Data System (ADS)

The authors have considered various designs for a high resolution spaceborne spectrometer for point-source astronomy in the 400 - 1200 wavelength region. Their designs utilize as the primary collecting optic a 1-meter normal incidence primary mirror of 1arcsec quality. The authors find the most efficient design to be a multiple Rowland circle spectrograph, with four toroidal gratings each intercepting a fraction of the beam from the primary mirror. The specific parameters of the design (line densities, detector size and pixel size, etc.) are dependent on the drift rate of the space platform. The authors present a design optimized for an uncorrected drift of 4arcsec. This design delivers a resolution of 3000 - 4000 and an effective area (including detector quantum efficiency) of 1 to 6.5 square centimeters across the bandpass.

Hurwitz, Mark; Bowyer, Stuart

1986-01-01

411

High-resolution mapping of motor vehicle carbon dioxide emissions  

NASA Astrophysics Data System (ADS)

fuel-based inventory for vehicle emissions is presented for carbon dioxide (CO2) and mapped at various spatial resolutions (10 km, 4 km, 1 km, and 500 m) using fuel sales and traffic count data. The mapping is done separately for gasoline-powered vehicles and heavy-duty diesel trucks. Emission estimates from this study are compared with the Emissions Database for Global Atmospheric Research (EDGAR) and VULCAN. All three inventories agree at the national level within 5%. EDGAR uses road density as a surrogate to apportion vehicle emissions, which leads to 20-80% overestimates of on-road CO2 emissions in the largest U.S. cities. High-resolution emission maps are presented for Los Angeles, New York City, San Francisco-San Jose, Houston, and Dallas-Fort Worth. Sharp emission gradients that exist near major highways are not apparent when emissions are mapped at 10 km resolution. High CO2 emission fluxes over highways become apparent at grid resolutions of 1 km and finer. Temporal variations in vehicle emissions are characterized using extensive day- and time-specific traffic count data and are described over diurnal, day of week, and seasonal time scales. Clear differences are observed when comparing light- and heavy-duty vehicle traffic patterns and comparing urban and rural areas. Decadal emission trends were analyzed from 2000 to 2007 when traffic volumes were increasing and a more recent period (2007-2010) when traffic volumes declined due to recession. We found large nonuniform changes in on-road CO2 emissions over a period of ~5 years, highlighting the importance of timely updates to motor vehicle emission inventories.

McDonald, Brian C.; McBride, Zoe C.; Martin, Elliot W.; Harley, Robert A.

2014-05-01

412

Tensor Distribution Function in Multiple Shell High Angular Resolution Diffusion Imaging  

E-print Network

Tensor Distribution Function in Multiple Shell High Angular Resolution Diffusion Imaging Liang Zhan ODF plot, while high b shell data has partial information loss in the fiber crossing region, Wedeen VJ. High angular resolution diffusion imaging re

Thompson, Paul

413

ON THE IMPACT OF SUPER RESOLUTION WSR-88D DOPPLER RADAR DATA ASSIMILATION ON HIGH RESOLUTION NUMERICAL MODEL FORECASTS  

SciTech Connect

Assimilation of radar velocity and precipitation fields into high-resolution model simulations can improve precipitation forecasts with decreased 'spin-up' time and improve short-term simulation of boundary layer winds (Benjamin, 2004 & 2007; Xiao, 2008) which is critical to improving plume transport forecasts. Accurate description of wind and turbulence fields is essential to useful atmospheric transport and dispersion results, and any improvement in the accuracy of these fields will make consequence assessment more valuable during both routine operation as well as potential emergency situations. During 2008, the United States National Weather Service (NWS) radars implemented a significant upgrade which increased the real-time level II data resolution to 8 times their previous 'legacy' resolution, from 1 km range gate and 1.0 degree azimuthal resolution to 'super resolution' 250 m range gate and 0.5 degree azimuthal resolution (Fig 1). These radar observations provide reflectivity, velocity and returned power spectra measurements at a range of up to 300 km (460 km for reflectivity) at a frequency of 4-5 minutes and yield up to 13.5 million point observations per level in super-resolution mode. The migration of National Weather Service (NWS) WSR-88D radars to super resolution is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current operational mesoscale model domains utilize grid spacing several times larger than the legacy data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of super resolution reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution is investigated here to determine the impact of the improved data resolution on model predictions.

Chiswell, S

2009-01-11

414

High Resolution Energetic X-ray Imager (HREXI)  

NASA Astrophysics Data System (ADS)

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 nIR telescope in spece, will enable GRBs to be used as probes of the formation of the first stars and structure in the Universe. HREXI on its own, with broad bandwidth and high spectral and spatial resolution, will extend both Galactic surveys for obscured young supernova remnants (44Ti sources) and for transients, black holes and flaring AGN and TDEs well at greatly increased sensitivity and spatial/spectral resolution than has been done with Swift or INTEGRAL. If the HREXI-1 technology is developed in the first year of this proposed effort, it could be used on the upcoming Brazil-US MIRAX telescope on the Lattes satellite, scheduled for a 2018 launch with imaging detector planes to be provided (under contract) by our group. Finally, the 3D stacking technology development proposed here for imaging detector arrays has broad application to Wide Field soft X-ray imaging, to CMB polarization mode (B mode) imaging detectors with very high detector-pixel count, and to Homeland Security.

Grindlay, Jonathan

415

A high-resolution bedrock map for the Antarctic Peninsula  

NASA Astrophysics Data System (ADS)

Glaciers on the Antarctic Peninsula show a high sensitivity to changed climatic and oceanic conditions and are expected to significantly contribute to sea-level rise over the next decades. So far, the best bedrock data set for the region is the recently released Bedmap2 providing ice thickness on a 1 km grid. Whereas for large-scale ice sheet modelling the spatial resolution provided by Bedmap2 is sufficient, detailed considerations of surface mass balance, ice flow and grounding line dynamics of Antarctic Peninsula glaciers necessitate the application of models that are able to cope with the high spatial variability of the governing processes. For ice flow models used to predict future glacier response to climate change and/or ice shelf break-off, a high-resolution bedrock topography is required as an essential boundary condition. Here, we derive a complete bedrock data set for the Antarctic Peninsula north of 70S on a 100 m grid. We further develop an established method to invert surface topography using simple ice dynamic modelling to obtain distributed ice thickness. Our approach makes use of a high-resolution digital elevation model, catchment boundaries for all glaciers of the Peninsula, and RACMO-based surface mass balance data. The results are constrained with all available thickness measurements from Operation IceBridge and gridded ice flow speeds for the entire study region. The new data set resolves the rugged subglacial topography in great detail, indicates deeply incised troughs with thicknesses of up to 1500 m, and shows that 32% of the ice volume is grounded below sea level. The Antarctic Peninsula has the potential to raise global sea level by 71.95.8 mm. In comparison to Bedmap2 we find a significantly higher mean ice thickness (+47%) which is attributed to the approach used to calculate thickness in regions not covered with direct measurements. Our high-resolution bedrock data set offers new possibilities for studying the contribution of the Antarctic Peninsula to sea-level rise with state-of-the-art glacier models.

Huss, Matthias; Farinotti, Daniel

2014-05-01

416

Computational analysis of high resolution unsteady airloads for rotor aeroacoustics  

NASA Technical Reports Server (NTRS)

The study of helicopter aerodynamic loading for acoustics applications requires the application of efficient yet accurate simulations of the velocity field induced by the rotor's vortex wake. This report summarizes work to date on the development of such an analysis, which builds on the Constant Vorticity Contour (CVC) free wake model, previously implemented for the study of vibratory loading in the RotorCRAFT computer code. The present effort has focused on implementation of an airload reconstruction approach that computes high resolution airload solutions of rotor/rotor-wake interactions required for acoustics computations. Supplementary efforts on the development of improved vortex core modeling, unsteady aerodynamic effects, higher spatial resolution of rotor loading, and fast vortex wake implementations have substantially enhanced the capabilities of the resulting software, denoted RotorCRAFT/AA (AeroAcoustics). Results of validation calculations using recently acquired model rotor data show that by employing airload reconstruction it is possible to apply the CVC wake analysis with temporal and spatial resolution suitable for acoustics applications while reducing the computation time required by one to two orders of magnitude relative to that required by direct calculations. Promising correlation with this body of airload and noise data has been obtained for a variety of rotor configurations and operating conditions.

Quackenbush, Todd R.; Lam, C.-M. Gordon; Wachspress, Daniel A.; Bliss, Donald B.

1994-01-01

417

High-resolution and broadband all-fiber spectrometers  

E-print Network

The development of optical fibers has revolutionized telecommunications by enabling long-distance broad-band transmission with minimal loss. In turn, the ubiquity of high-quality low-cost fibers enabled a number of additional applications, including fiber sensors, fiber lasers, and imaging fiber bundles. Recently, we showed that a mutlimode optical fiber can also function as a spectrometer by measuring the wavelength-dependent speckle pattern formed by interference between the guided modes. Here, we reach a record resolution of 1 pm at wavelength 1500 nm using a 100 meter long multimode fiber, outperforming the state-of-the-art grating spectrometers. we also achieved broad-band operation with a 4 cm long fiber, covering 400 nm - 750 nm with 1 nm resolution. The fiber spectrometer, consisting of the fiber which can be coiled to a small volume and a monochrome camera that records the speckle pattern, is compact, lightweight, and low cost while providing ultrahigh resolution, broad bandwidth and low loss.

Redding, Brandon; Seifert, Martin; Cao, Hui

2014-01-01

418

Single-molecule high-resolution imaging with photobleaching  

PubMed Central

Conventional light microscopy is limited in its resolving power by the Rayleigh limit to length scales on the order of 200 nm. On the other hand, spectroscopic techniques such as fluorescence resonance energy transfer cannot be used to measure distances >10 nm, leaving a gap in the ability of optical techniques to measure distances on the 10- to 100-nm scale. We have previously demonstrated the ability to localize single dye molecules to a precision of 1.5 nm with subsecond time resolution. Here we locate the position of two dyes and determine their separation with 5-nm precision, using the quantal photobleaching behavior of single fluorescent dye molecules. By fitting images both before and after photobleaching of one of the dyes, we may localize both dyes simultaneously and compute their separation. Hence, we have circumvented the Rayleigh limit and achieved nanometer-scale resolution. Specifically, we demonstrate the technique by measuring the distance between single fluorophores separated by 1020 nm via attachment to the ends of double-stranded DNA molecules immobilized on a surface. In addition to bridging the gap in optical resolution, this technique may be useful for biophysical or genomic applications, including the generation of super-high-density maps of single-nucleotide polymorphisms. PMID:15096603

Gordon, Matthew P.; Ha, Taekjip; Selvin, Paul R.

2004-01-01

419

Extraction and labeling high-resolution images from PDF documents  

NASA Astrophysics Data System (ADS)

Accuracy of content-based image retrieval is affected by image resolution among other factors. Higher resolution images enable extraction of image features that more accurately represent the image content. In order to improve the relevance of search results for our biomedical image search engine, Open-I, we have developed techniques to extract and label high-resolution versions of figures from biomedical articles supplied in the PDF format. Open-I uses the open-access subset of biomedical articles from the PubMed Central repository hosted by the National Library of Medicine. Articles are available in XML and in publisher supplied PDF formats. As these PDF documents contain little or no meta-data to identify the embedded images, the task includes labeling images according to their figure number in the article after they have been successfully extracted. For this purpose we use the labeled small size images provided with the XML web version of the article. This paper describes the image extraction process and two alternative approaches to perform image labeling that measure the similarity between two images based upon the image intensity projection on the coordinate axes and similarity based upon the normalized cross-correlation between the intensities of two images. Using image identification based on image intensity projection, we were able to achieve a precision of 92.84% and a recall of 82.18% in labeling of the extracted images.

Chachra, Suchet K.; Xue, Zhiyun; Antani, Sameer; Demner-Fushman, Dina; Thoma, George R.

2013-12-01

420

High-resolution retinal imaging with micro adaptive optics system.  

PubMed

Based on the dynamic characteristics of human eye aberration, a microadaptive optics retina imaging system set is established for real-time wavefront measurement and correction. This paper analyzes the working principles of a 127-unit Hartmann-Shack wavefront sensor and a 37-channel micromachine membrane deformable mirror adopted in the system. The proposed system achieves wavefront reconstruction through the adaptive centroid detection method and the mode reconstruction algorithm of Zernike polynomials, so that human eye aberration can be measured accurately. Meanwhile, according to the adaptive optics aberration correction control model, a closed-loop iterative aberration correction algorithm based on Smith control is presented to realize efficient and real-time correction of human eye aberration with different characteristics, and characteristics of the time domain of the system are also optimized. According to the experiment results tested on a USAF 1951 standard resolution target and a living human retina (subject ZHY), the resolution of the system can reach 3.6?LP/mm, and the human eye wavefront aberration of 0.728? (?=785?nm) can be corrected to 0.081? in root mean square (RMS) so as to achieve the diffraction limit (Strehl ratio is 0.866), then high-resolution retina images are obtained. PMID:21833112

Niu, Saisai; Shen, Jianxin; Liang, Chun; Zhang, Yunhai; Li, Bangming

2011-08-01

421

High-resolution retinal imaging with micro adaptive optics system  

NASA Astrophysics Data System (ADS)

Based on the dynamic characteristics of human eye aberration, a microadaptive optics retina imaging system set is established for real-time wavefront measurement and correction. This paper analyzes the working principles of a 127-unit Hartmann--Shack wavefront sensor and a 37-channel micromachine membrane deformable mirror adopted in the system. The proposed system achieves wavefront reconstruction through the adaptive centroid detection method and the mode reconstruction algorithm of Zernike polynomials, so that human eye aberration can be measured accurately. Meanwhile, according to the adaptive optics aberration correction control model, a closed-loop iterative aberration correction algorithm based on Smith control is presented to realize efficient and real-time correction of human eye aberration with different characteristics, and characteristics of the time domain of the system are also optimized. According to the experiment results tested on a USAF 1951 standard resolution target and a living human retina (subject ZHY), the resolution of the system can reach 3.6LP/mm, and the human eye wavefront aberration of 0.728 ? (?=785nm) can be corrected to 0.081 ? in root mean square (RMS) so as to achieve the diffraction limit (Strehl ratio is 0.866), then high-resolution retina images are obtained.

Niu, Saisai; Shen, Jianxin; Liang, Chun; Zhang, Yunhai; Li, Bangming

2011-08-01

422

CSpace high-resolution volumetric 3D display  

NASA Astrophysics Data System (ADS)

We are currently in the process of developing a static-volume 3D display, CSpace display, that has the capability to produce images of much larger size than any other static-volume display currently under development, with up to nearly 800 million voxel resolution. A key component in achieving the size and resolution of the display is the optical system that transfers the pixel data from a standard DMD projection unit to the voxel size required by the display with high contrast and minimal distortion. The current optical system is capable of such performance for only small image sizes, and thus new designs of the optical system must be developed. We report here on the design and testing of a new optical projection system with the intent of achieving performance close to that of a telecentric lens. Theoretical analysis with Zemax allowed selection of appropriate lens size, spacing, and focal length, and identified the need for tilting the assembly to produce the desired beam properties. Experimental analysis using the CSpace prototype showed that the improved beam parameters allowed for higher resolution and brighter images than those previously achieved, though their remains room for further improvement of the design. Heating of the DMD and its housing components were also addressed to minimize heating effects on the optical system. A combination of a thermo-electric cooler and a small fan produced sufficient cooling to stabilize the temperature of the system to acceptable levels.

Refai, Hakki H.; Melnik, George; Willner, Mark

2013-05-01

423

HIRIS - EOS instrument with high spectral and spatial resolution  

NASA Technical Reports Server (NTRS)

The High-Resolution Imaging Spectrometer (HIRIS) is designed for NASA's Earth Observing System (EOS). It will have 10-nm wide spectral bands from 0.4-2.5 microns at 30 m spatial resolution over a 30 km swath. The spectral resolution allows identification of many minerals in rocks and soils, important algal pigments in oceans and inland waters, spectral changes associated with plant canopy biochemistry, composition of atmospheric aerosols, and grain size of snow and contamination by absorbing impurities. The bands will have 12-bit quantization over a dynamic range suitable for bright targets, such as snow. For targets of low brightness, such as water bodies, image-motion compensation will allow gains up to a factor of 8 to increase signal-to-noise ratios. The sensor will be able to point + or - 24 deg crosstrack and +60/-30 deg downtrack. In the 824-km orbit altitude proposed for EOS, the crosstrack pointing capability will allow 4-5 views during a 16-day revisit cycle.

Dozier, Jeff; Goetz, Alexander F. H.

1987-01-01

424

High energy resolution with transparent ceramic garnet scintillators  

NASA Astrophysics Data System (ADS)

Breakthrough energy resolution, R(662keV) < 4%, has been achieved with an oxide scintillator, Cerium-doped Gadolinium Yttrium Gallium Aluminum Garnet, or GYGAG(Ce). Transparent ceramic GYGAG(Ce), has a peak emission wavelength of 550 nm that is better matched to Silicon photodetectors than to standard PMTs. We are therefore developing a spectrometer based on pixelated GYGAG(Ce) on a Silicon photodiode array that can provide R(662 keV) = 3.6%. In comparison, with large 1-2 in3 size GYGAG(Ce) ceramics we obtain R(662 keV) = 4.6% with PMT readout. We find that ceramic GYGAG(Ce) of a given stoichiometric chemical composition can exhibit very different scintillation properties, depending on sintering conditions and post-anneal treatments. Among the characteristics of transparent ceramic garnet scintillators that can be controlled by fabrication conditions are: scintillation decay components and their amplitudes, intensity and duration of afterglow, thermoluminescence glow curve peak positions and amplitudes, integrated light yield, light yield non-proportionality - as measured in the Scintillator Light Yield Non-Proportionality Characterization Instrument (SLYNCI), and energy resolution for gamma spectroscopy. Garnet samples exhibiting a significant fraction of Cerium dopant in the tetravalent valence also exhibit: faster overall scintillation decay, very low afterglow, high light yield, but poor light yield proportionality and degraded energy resolution.

Cherepy, N. J.; Seeley, Z. M.; Payne, S. A.; Beck, P. R.; Swanberg, E. L.; Hunter, S.; Ahle, L.; Fisher, S. E.; Melcher, C.; Wei, H.; Stefanik, T.; Chung, Y.-S.; Kindem, J.

2014-09-01

425

Designing arrays for modern high-resolution methods  

SciTech Connect

A bearing estimation study of seismic wavefields propagating from a strongly heterogeneous media shows that with the high-resolution MUSIC algorithm the bias of the direction estimate can be reduced by adopting a smaller aperture sub-array. Further, on this sub-array, the bias of the MUSIC algorithm is less than those of the MLM and Bartlett methods. On the full array, the performance for the three different methods are comparable. Improvement in bearing estimation in MUSIC with a reduced aperture might be attributed to increased signal coherency in the array. For methods with less resolution, the improved signal coherency in the smaller array is possible being offset by severe loss of resolution and the presence of weak secondary sources. Building upon the characteristics of real seismic wavefields, a design language has been developed to generate, modify, and test other arrays. Eigenstructures of wavefields and arrays have been studied empirically by simulation of a variety of realistic signals. 6 refs., 5 figs.

Dowla, F.U.

1987-10-01

426

Resolution of a High Performance Cavity Beam Positron Monitor System  

SciTech Connect

International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved--ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of +/- 20 microns.

Walston, S.; Chung, C.; Fitsos, P.; Gronberg, J.; /LLNL, Livermore; Ross, M.; /Fermilab; Khainovski, O.; Kolomensky, Y.; Loscutoff, P.; /LBL, Berkeley; Slater, M.; Thomson, M.; Ward, D.; /Cambridge U.; Boogert, S.; /Royal Holloway, U. of London; Vogel, V.; /DESY; Meller, R.; /Cornell U., LNS; Lyapin, A.; Malton, S.; Miller, D.; /University Coll. London; Frisch, J.; Hinton, S.; May, J.; McCormick, D.; /SLAC /Caltech /KEK, Tsukuba

2007-07-06

427

A comparative study of high resolution microscopy imaging modalities using a three-dimensional resolution measure  

PubMed Central

From an acquired image, single molecule microscopy makes possible the determination of the distance separating two closely spaced biomolecules in three-dimensional (3D) space. Such distance information can be an important indicator of the nature of the biomolecular interaction. Distance determination, however, is especially difficult when, for example, the imaged point sources are very close to each other or are located near the focal plane of the imaging setup. In the context of such challenges, we compare the limits of the distance estimation accuracy for several high resolution 3D imaging modalities. The comparisons are made using a Cramer-Rao lower bound-based 3D resolution measure which predicts the best possible accuracy with which a given distance can be estimated. Modalities which separate the detection of individual point sources (e.g., using photoactivatable fluorophores) are shown to provide the best accuracy limits when the two point sources are very close to each other and/or are oriented near parallel to the optical axis. Meanwhile, modalities which implement the simultaneous imaging of the point sources from multiple focal planes perform best when given a near-focus point source pair. We also demonstrate that the maximum likelihood estimator is capable of attaining the limit of the accuracy predicted for each modality. PMID:20052148

Chao, Jerry; Ram, Sripad; Ward, E. Sally; Ober, Raimund J.

2012-01-01

428

High resolution solar observations from first principles to applications  

NASA Astrophysics Data System (ADS)

The expression "high-resolution observations" in Solar Physics refers to the spatial, temporal and spectral domains in their entirety. High-resolution observations of solar fine structure are a necessity to answer many of the intriguing questions related to solar activity. However, a researcher building instruments for high-resolution observations has to cope with the fact that these three domains often have diametrically opposed boundary conditions. Many factors have to be considered in the design of a successful instrument. Modern post-focus instruments are more closely linked with the solar telescopes that they serve than in past. In principle, the quest for high-resolution observations already starts with the selection of the observatory site. The site survey of the Advanced Technology Solar Telescope (ATST) under the stewardship of the National Solar Observatory (NSO) has identified Big Bear Solar Observatory (BBSO) as one of the best sites for solar observations. In a first step, the seeing characteristics at BBSO based on the data collected for the ATST site survey are described. The analysis will aid in the scheduling of high-resolution observations at BBSO as well as provide useful information concerning the design and implementation of a thermal control system for the New Solar Telescope (NST). NST is an off-axis open-structure Gregorian-style telescope with a 1.6 m aperture. NST will be housed in a newly constructed 5/8-sphere ventilated dome. With optics exposed to the surrounding air, NST's open-structure design makes it particularly vulnerable to the effects of enclosure-related seeing. In an effort to mitigate these effects, the initial design of a thermal control system for the NST dome is presented. The goal is to remediate thermal related seeing effects present within the dome interior. The THermal Control System (THCS) is an essential component for the open-telescope design of NST to work. Following these tasks, a calibration routine for the polarization optics for the Visible-light Imaging Magnetograph (VIM) is presented. VIM uses a set of two Liquid Crystal Variable Retarders (LCVRs) as the main components of its Stokes analyzer. Calibration of these components is a crucial step in providing reliable polarimetric measurements of the Sun using VIM. On 2007 July 15, using the Dunn Solar Telescope (DST) at the National Solar Observatory at Sacramento Peak (NSO/SP), New Mexico, the first polarimetric measurements using VIM were made. As a final step, illustrating an application of high-resolution solar observations, the results of a two-dimensional time-series acquired on 2006 June 11, using the DST at NSOP is presented. The data is used in a study of upflow events that are observed to occur in the Halpha 656.3 nm and Na D2 589.0 nm chromospheric absorption lines.

Verdoni, Angelo P.

2009-10-01

429

WINKLER - An imaging high resolution gamma-ray spectrometer  

NASA Astrophysics Data System (ADS)

The WINKLER high-resolution gamma-ray spectrometer was originally developed to fly on a high-altitude aircraft. Following the discovery of Supernova 1987A in the Large Magellanic Cloud, arrangements were made to perform balloon-borne observations of this event. The instrument was quickly adapted to fit on a gondola furnished by NASA/MSFC in a collaborative effort and was flown in a series of three successful flights from Alice Springs, Australia. The second flight on October 29-31, 1987 resulted in the first high-resolution detection of the 847-keV line emission from the decay of 56Co and provided definitive confirmation of the explosive nucleosynthesis process. WINKLER comprises an array of nine coaxial n-type germanium detectors which are housed in a common vaccuum cryostat and surrounded by an NaI(Tl) scintillator shield that suppresses Compton interactions and gamma-ray background. Gamma-ray images are obtained with a rotational modulation collimator system attached to the spectrometer. Collimator holes in the upper section of the shield define the angular field of view of the instrument to 22 deg FWHM. The energy range of the spectrometer is 20 eV to 8 MeV, and the composite energy resolution from all detectors is 1.5 keV at 100 keV and about 2.5 keV at 1.33 MeV. The total frontal area of the sensor array is 214 cm2 with a volume of 1177 cm3, providing sufficient detection sensitivity for gamma-ray astronomy as well as for land-based applications such as treaty verification monitoring.

Nakano, G. H.; Sandie, W. G.; Kilner, J. R.; Pang, F.; Imai, B. B.

1991-04-01

430

A High Resolution Radar Survey of the Lunar Near Side  

NASA Astrophysics Data System (ADS)

Since 2005 we have been using the Arecibo 13 cm transmitting system and the 100 m Green Bank Telescope (GBT) in a bi-static radar configuration for multi-polarization imaging of the lunar surface at resolutions as fine as 20 m. A circularly polarized wave is transmitted and the echo received in both senses of received circular polarization, allowing imaging in the full Stokes polarization parameters of the reflected signal. The initial objective was the South Pole region, with emphasis on high-resolution images of possible landing sites and polarimetric analysis of putative ice deposits (D. Campbell et al, 2006 Nature, 443, 835). A byproduct of this work was a method for clearly identifying secondary craters from Tycho via their circular polarization ratio signature (K. Wells et al, 2006, DPS abst). Subsequent observations have concentrated on studies of pyroclastic deposits including potentially resource-rich areas such as the Aristarchus plateau, where the radar's ability to probe the sub-surface has allowed the subsurface rock distribution to be investigated (B. Campbell et al, 2008, Geology, 36, 135; Carter et al, 2007 LPSC Conf. 38, Houston, Texas). We have begun a systematic mapping program that will image most of the near side of the Moon in the full Stokes parameters. The initial product is a large area image of the south-polar region at 20 m resolution, with one look (see http://arecibo.tc.cornell.edu/lunarimages/default.aspx). To reduce the required observation time to an acceptable level, subsequent images will be at 80 m resolution, four looks. The results will be made available through the PDS. We acknowledge the NASA Planetary Astronomy program for partial support of this work and NAIC and NRAO for making Arecibo and the GBT available for the observations.

Campbell, Donald B.; Campbell, B. A.; Carter, L. M.; Ghent, R. R.; Nolan, M. C.; Wells, K. S.

2008-09-01

431

Wide-Field-of-View, High-Resolution, Stereoscopic Imager  

NASA Technical Reports Server (NTRS)

A device combines video feeds from multiple cameras to provide wide-field-of-view, high-resolution, stereoscopic video to the user. The prototype under development consists of two camera assemblies, one for each eye. One of these assemblies incorporates a mounting structure with multiple cameras attached at offset angles. The video signals from the cameras are fed to a central processing platform where each frame is color processed and mapped into a single contiguous wide-field-of-view image. Because the resolution of most display devices is typically smaller than the processed map, a cropped portion of the video feed is output to the display device. The positioning of the cropped window will likely be controlled through the use of a head tracking device, allowing the user to turn his or her head side-to-side or up and down to view different portions of the captured image. There are multiple options for the display of the stereoscopic image. The use of head mounted displays is one likely implementation. However, the use of 3D projection technologies is another potential technology under consideration, The technology can be adapted in a multitude of ways. The computing platform is scalable, such that the number, resolution, and sensitivity of the cameras can be leveraged to improve image resolution and field of view. Miniaturization efforts can be pursued to shrink the package down for better mobility. Power savings studies can be performed to enable unattended, remote sensing packages. Image compression and transmission technologies can be incorporated to enable an improved telepresence experience.

Prechtl, Eric F.; Sedwick, Raymond J.

2010-01-01

432

High resolution modeling of the cusp density anomaly  

NASA Astrophysics Data System (ADS)

The Earth's magnetospheric cusp provides direct access of energetic particles to the thermosphere causing an ionization anomaly. The energy from these particles along with Joule heating, and ion drag forcing play a direct role in determining the neutral density structure in the cusp region. Measurements by the CHAMP (390-460 km altitudes) have shown a region of strong enhanced density attributed to upwelling caused by the combination of particle and Joule heating. The Streak mission (325-123 km) observed a relative depletion in density in the cusp which was attributed to soft particle precipitation not being adequate to cause upwelling at the lower altitudes sampled by Streak and relatively harder precipitation in adjacent areas. Recent attempts to model the cusp density anomaly with Global Circulation Models (GCM) have focused on extreme cases with forcing extending over latitudinal cusp widths of 4 degrees or more which are at the extreme upper end of the observations. Even at one degree latitudinal resolution the cusp features are marginally captured. More typical cusps widths of 1-2 degrees in latitude require finer resolution to resolve. We use a high-resolution numerical model of the thermosphere to simulate the atmospheric response to the relevant forcing by realistically specifying the particle heating, Joule heating, and ion drag forcing to examine the dependence of the magnitude of the cusp density anomaly and the corresponding wind structure on the characteristics of the forcing in the cusp. We ran simulations for cusp widths of 4 and 2 degrees latitude using a model resolution of 20 km. We found that reducing the cusp width by half reduced the density response in the cusp by half, but that the wind response was only slightly decreased. We compare the model results to CHAMP and Streak observations and assess the relative contributions of these mechanisms in explaining the distinctive features of the observations. Acknowledgements: This research was supported by The Aerospace Corporation's Technical Investment program

Brinkman, D. G.; Walterscheid, R. L.; Clemmons, J. H.

2013-12-01

433

Reconfigurable Pointing Control for High Resolution Space Spectroscopy  

NASA Technical Reports Server (NTRS)

In this paper, a pointing control performance criteria is established to support high resolution space spectroscopy. Results indicate that these pointing requirements are very stringent, and would typically be difficult to meet using standard 3-axis spacecraft control. To resolve this difficulty, it is shown that performance can be significantly improved using a reconfigurable control architecture that switches among a small bank of detuned Kalman filters. The effectiveness of the control reconfiguration approach is demonstrated by example on the Space Infra, Red Telescope Facility (SIRTF) pointing system, in support of the Infrared Spectrograph (IRS) payload.

Bayard, David S.; Kia, Tooraj; vanCleve, Jeffrey

1997-01-01

434

High time resolution studies of binary x ray pulsars  

NASA Technical Reports Server (NTRS)

This report covers the period September 1, 1992 through August 1, 1993 for NASA grant NAG 5-1260 through the Astrophysics Data Program (ADP), for the project 'High Time Resolution Studies of Binary X-ray Pulsars'. During the past 11 months, we have concentrated on scientific analysis of the data, and have had to reanalyze several data sets, due to a newly discovered error in the unpacking of the count rate data. This error has now been corrected, but may have caused us to miss some scientific results, so we have gone back and reanalyzed the affected data sets, as well as continuing our analysis of other objects.

Cominsky, Lynn R.

1992-01-01

435

A compound representation of high resolution sea clutter  

NASA Astrophysics Data System (ADS)

Measurements of sea clutter at low grazing angles using high resolution radar show that the probability density function, p(x), of envelope detected clutter is not Rayleigh. Based on time averaged sea clutter recordings, a compound form of p(x) is proposed leading to the K distribution for the overall p(x). This model is then used to explain both the non Rayleigh nature of the clutter and also the correlation properties for fixed frequency and frequency agile radar returns. Illustrations are given of applications to signal processing performance calculations along with some results for a fixed threshold.

Ward, K. D.

1980-09-01

436

High Resolution Coude Echelle Spectroscopy of IX Per  

NASA Astrophysics Data System (ADS)

High resolution (R = 45000) Coude-Echelle spectra of IX Per has been obtained at TB?TAK National Observatory (TUG) of Turkey. IX Per has been known to be a single lined (SB1) spectroscopic binary having chromospheric activity. However, analyzed spectra of IX Per by KOREL disentangling method indicated that the system is a double lined (SB2) spectroscopic binary. Weaker lines from the secondary are discovered on the decomposed spectra. A preliminary orbit indicates that the mass ratio of the system is 0.64. The light contribution of the secondary is up to 10% in investigated spectral region. Circular orbit is sufficient to explain radial velocity variations.

Ak, N. Filiz; Eker, Z.; Ak, H.; Kk, I.

2009-02-01

437

Applied high resolution geophysical methods: Offshore geoengineering hazards  

SciTech Connect

This book is an examination of the purpose, methodology, equipment, and data interpretation of high-resolution geophysical methods, which are used to assess geological and manmade engineering hazards at offshore construction locations. It is a state-of-the-art review. Contents: 1. Introduction. 2. Maring geophysics, an overview. 3. Marine geotechnique, an overview. 4. Echo sounders. 5. Side scan sonar. 6. Subbottom profilers. 7. Seismic sources. 8. Single-channel seismic reflection systems. 9. Multifold acquisition and digital processing. 10. Marine magnetometers. 11. Marine geoengineering hazards. 12. Survey organization, navigation, and future developments. Appendix. Glossary. References. Index.

Trabant, P.K.

1984-01-01

438

High-order centered difference methods with sharp shock resolution  

NASA Technical Reports Server (NTRS)

In this paper we consider high-order centered finite difference approximations of hyperbolic conservation laws. We propose different ways of adding artificial viscosity to obtain sharp shock resolution. For the Riemann problem we give simple explicit formulas for obtaining stationary one and two-point shocks. This can be done for any order of accuracy. It is shown that the addition of artificial viscosity is equivalent to ensuring the Lax k-shock condition. We also show numerical experiments that verify the theoretical results.

Gustafsson, Bertil; Olsson, Pelle

1994-01-01

439

A High Resolution Microprobe Study of EETA79001 Lithology C  

NASA Technical Reports Server (NTRS)

Antarctic meteorite EETA79001 has received substantial attention for possibly containing a component of Martian soil in its impact glass (Lithology C) [1]. The composition of Martian soil can illuminate near-surface processes such as impact gardening [2] and hydrothermal and volcanic activity [3,4]. Impact melts in meteorites represent our most direct samples of Martian regolith. We present the initial findings from a high-resolution electron microprobe study of Lithology C from Martian meteorite EETA79001. As this study develops we aim to extract details of a potential soil composition and to examine Martian surface processes using elemental ratios and correlations.

Schrader, Christian M.; Cohen, B. A.; Donovan, J. J.; Vicenzi, E. P.

2010-01-01

440

Clickstream data yields high-resolution maps of science  

SciTech Connect

Intricate maps of science have been created from citation data to visualize the structure of scientific activity. However, most scientific publications are now accessed online. Scholarly web portals record detailed log data at a scale that exceeds the number of all existing citations combined. Such log data is recorded immediately upon publication and keeps track of the sequences of user requests (clickstreams) that are issued by a variety of users across many different domains. Given these advantagees of log datasets over citation data, we investigate whether they can produce high-resolution, more current maps of science.

Bollen, Johan [Los Alamos National Laboratory; Van De Sompel, Herbert [Los Alamos National Laboratory; Hagberg, Aric [Los Alamos National Laboratory; Bettencourt, Luis [Los Alamos National Laboratory; Chute, Ryan [Los Alamos National Laboratory; Rodriguez, Marko A [Los Alamos National Laboratory; Balakireva, Lyudmila [Los Alamos National Laboratory

2009-01-01