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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 Autoradiography of Escherichia coli Cells Infected with Bacteriophage R17  

PubMed Central

Granboulan, Nicole (Institute de Recherches sur le Cancer, Villejuif, Seine, France), and Richard M. Franklin. High-resolution autoradiography of Escherichia coli cells infected with bacteriophage R17. J. Bacteriol. 91:849–857. 1966.—The ultrastructural alterations in Escherichia coli infected with the RNA bacteriophage R17 were further investigated by means of the technique of high-resolution autoradiography. Tritiated precursors to ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein were employed in separate experiments. A striking inhibition of cellular RNA, DNA, and protein synthesis was noted. Whereas normal RNA synthesis occurs in the nucleoid, in infected cells RNA synthesis is predominantly cytoplasmic, but later in the latent period, and during the stage of active viral growth, the label is localized in a polar region. In the late stages of viral growth, RNA synthesis occurs only around the crystals. Protein synthesis also becomes localized in a polar region, but DNA synthesis remains confined to the nucleoid. Under conditions of chloramphenicol inhibition of viral-coat protein synthesis, RNA label is localized in the paranuclear lesion, providing further indication that RNA forms this fibrillar structure. Images

Granboulan, Nicole; Franklin, Richard M.

1966-01-01

3

High resolution track etch autoradiography  

DOEpatents

A detector assembly 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.

Solares, Guido (Arlington, MA); Zamenhof, Robert G. (Brookline, MA)

1994-01-01

4

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

5

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

6

A sensitive high resolution neutron imaging detector  

NASA Astrophysics Data System (ADS)

We present a two-step method for a high-resolution neutron area detector in which a metal foil with a high absorption cross section acts as a neutron to charged particle converter. After the foil is activated, the neutron field information is transferred from the converter foil to an imaging device by autoradiography. This two-step process using a storage photostimulable phosphor avoids interferences from non-neutron radiation found in the radiation field.

Cheng, Y. T.; Mildner, D. F. R.

2000-11-01

7

High resolution microwave survey  

NASA Astrophysics Data System (ADS)

Research information on radar tracking systems, computer animation of star formation, footage of solar systems, and desert radar equipment and research facilities are contained in this video. Frank Drake, President of SETI (Search for Extraterrestrial Intelligence) Institute is interviewed along with Jill Tarter, NASA's High Resolution Microwave Survey Project Scientist.

Scheibe, J.

1992-09-01

8

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

9

High resolution data acquisition  

DOEpatents

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

Thornton, Glenn W. (Los Alamos, NM); Fuller, Kenneth R. (Los Alamos, NM)

1993-01-01

10

High resolution infrared measurements  

NASA Technical Reports Server (NTRS)

Sample ground based cloud radiance data from a high resolution infrared sensor are shown and the sensor characteristics are presented in detail. The purpose of the Infrared Analysis Measurement and Modeling Program (IRAMMP) is to establish a deterministic radiometric data base of cloud, sea, and littoral terrain clutter to be used to advance the design and development of Infrared Search and Track (IRST) systems as well as other infrared devices. The sensor is a dual band radiometric sensor and its description, together with that of the Data Acquisition System (DAS), are given. A schematic diagram of the sensor optics is shown.

Kessler, B.; Cawley, Robert

1990-01-01

11

High resolution Doppler lidar  

NASA Technical Reports Server (NTRS)

A high resolution lidar system was implemented to measure winds in the lower atmosphere. The wind speed along the line of sight was determined by measuring the Doppler shift of the aerosol backscattered laser signal. The system in its present configuration is stable, and behaves as indicated by theoretical simulations. This system was built to demonstrate the capabilities of the detector system as a prototype for a spaceborne lidar. The detector system investigated consisted of a plane Fabry-Perot etalon, and a 12-ring anode detector. This system is generically similar to the Fabry-Perot interferometer developed for passive wind measurements on board the Dynamics Explorer satellite. That this detector system performs well in a lidar configuration was demonstrated.

Abreu, Vincent J.; Hays, Paul B.; Barnes, John E.

1989-01-01

12

Interferometer. [high resolution  

NASA Technical Reports Server (NTRS)

A high resolution interferometer is described. The interferometer is insensitive to slight misalignment of its elements, avoids channeling in the spectrum, generates a maximum equal path fringe contrast, produces an even two sided interferogram without critical matching of the wedge angles of the beamsplitter and compensator wedges, and is optically phase tunable. The interferometer includes a mirror along the path of each beam component produced by the beamsplitter, for reflecting the beam component from the beamsplitter, for reflecting the beam component from the beamsplitter to a corresponding retroreflector and for reflecting the beam returned by the retroreflector back to the beamsplitter. A wedge located along each beam component path, is large enough to cover the retroreflector, so that each beam component passes through the wedge during movement towards the retroreflector and away therefrom.

Breckinridge, J. B.; Norton, R. H.; Schindler, R. A. (inventors)

1981-01-01

13

High resolution angular sensor  

NASA Astrophysics Data System (ADS)

Specifications for the pointing stabilization system of the large space telescope were used in an investigation of the feasibility of reducing ring laser gyro output quantization to the sub-arc-second level by the use of phase locked loops and associated electronics. Systems analysis procedures are discussed and a multioscillator laser gyro model is presented along with data on the oscillator noise. It is shown that a second order closed loop can meet the measurement noise requirements when the loop gain and time constant of the loop filter are appropriately chosen. The preliminary electrical design is discussed from the standpoint of circuit tradeoff considerations. Analog, digital, and hybrid designs are given and their applicability to the high resolution sensor is examined. the electrical design choice of a system configuration is detailed. The design and operation of the various modules is considered and system block diagrams are included. Phase 1 and 2 test results using the multioscillator laser gyro are included.

Gneses, M. I.; Berg, D. S.

1981-06-01

14

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

15

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

16

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

17

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

18

Analysis of 18F-labelled synthesis products on TLC plates: comparison of radioactivity scanning, film autoradiography, and a phosphoimaging technique.  

PubMed

We compared radioactivity scanning, film autoradiography, and digital photostimulated luminescence (PSL) autoradiography (phosphoimaging technique) in detection of radioactivity on thin-layer chromatography (TLC) plates. TLC combined with radioactivity detection is rapid, simple, and relatively flexible. Here, (18)F-labelled synthesis products were analyzed by TLC and the radioactivity distribution on the plates determined using the three techniques. Radioactivity scanning is appropriate only with good chromatographic resolution and previously validated scanning parameters. Film autoradiography exhibits poor linearity if radioactivity varies greatly. PSL provides high sensitivity and resolution and superior linearity compared with the other methods. PMID:16860561

Kämäräinen, Eeva-Liisa; Haaparanta, Merja; Siitari-Kauppi, Marja; Koivula, Teija; Lipponen, Tiina; Solin, Olof

2006-09-01

19

High Resolution Formaldehyde Photochemistry  

NASA Astrophysics Data System (ADS)

Formaldehyde (HCHO) is the most abundant and most important organic carbonyl compound in the atmosphere. The sources of formaldehyde are the oxidation of methane, isoprene, acetone, and other volatile organic compounds (VOCs); fossil fuel combustion; and biomass burning. The dominant loss mechanism for formaldehyde is photolysis which occurs via two pathways: (R1) HCHO + hv ? HCO + H (R2) HCHO + hv ? H2 + CO The first pathway (R1) is referred to as the radical channel, while the second pathway (R2) is referred to as the molecular channel. The products of both pathways play a significant role in atmospheric chemistry. The CO that is produced in the molecular channel undergoes further oxidation to produce CO2. Under atmospheric conditions, the H atom and formyl radical that are produced in the radical channel undergo rapid reactions with O2 to produce the hydroperoxyl radical (HO2) via (R3) and (R4). (R3) HCO + O2 ? HO2 + CO (R4) H + O2 ? HO2 Thus, for every photon absorbed, the photolysis of formaldehyde can contribute one CO2 molecule to the global greenhouse budget or two HO2 radicals to the tropospheric HOx (OH + HO2) cycle. The HO2 radicals produced during formaldehyde photolysis have also been implicated in the formation of photochemical smog. The HO2 radicals act as radical chain carriers and convert NO to NO2, which ultimately results in the catalytic production of O3. Constraining the yield of HO2 produced via HCHO photolysis is essential for improving tropospheric chemistry models. In this study, both the absorption cross section and the quantum yield of the radical channel (R1) were measured at high resolution over the tropospherically relevant wavelength range 304-330 nm. For the cross section measurements a narrow linewidth Nd:YAG pumped dye laser was used with a multi-pass cell. Partial pressures of HCHO were kept below 0.3 torr. Simultaneous measurement of OH LIF in a flame allowed absolute calibration of the wavelength scale. Pressure broadening in He, O2, N2, and H2O bath gas was also examined. Measurements of the radical yield of HCHO photolysis were conducted by converting the H atom to OH through reaction with NO2 via (R5) and then detecting OH LIF using a Pulsed Laser Photolysis-Pulsed Laser Induced Fluorescence (PLP-PLIF) technique. (R5) H + NO2 ? NO + OH The resulting relative quantum yield was converted to an absolute yield by using Cl2 photolysis (and the subsequent reaction of the Cl atom with HCHO) coupled with a photofragment-LIF variation of the PLP-PLIF technique.

Ernest, C. T.; Bauer, D.; Hynes, A. J.

2010-12-01

20

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

21

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

22

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

23

MicromachinedHigh-Resolution Accelerometers  

Microsoft Academic Search

In this paper, we review the high-resolution, micromachined accelerometers by enunciating the development of their mechanical components, the electronic circuitry and the microfabrication processes. A survey of the literature suggests that the research in this area is mostly focused on improving microfabrication and electronic circuitry. The resolution of the accelerometers is dependent on the sensitivity of the mechanical components as

Girish Krishnan; Chaitanya U. Kshirsagar; G. K. Ananthasuresh; Navakanta Bhat

24

High resolution tomographic instrument development.  

National Technical Information Service (NTIS)

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 th...

1992-01-01

25

High resolution digital delay timer  

DOEpatents

Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

Martin, Albert D. (Los Alamos, NM) [Los Alamos, NM

1988-01-01

26

Very high resolution virtual display  

NASA Astrophysics Data System (ADS)

A virtual display with 1120 X 900 pixel resolution has been constructed using a high density LED array and scanning optics. The display has a field of view of 25 degree(s) X 20 degree(s). The display is small, light weight, and suitable for hand-held or head-mounted use. Pixels appear red on a jet black background. Individual pixel size is 1.3 arc minutes, which is near the resolution limit of the human eye. Pixels appear crisp and sharply defined. Contrast ratio is over 500:1. The paper describes operation of the display in detail, and discusses design tradeoffs encountered in the development of high resolution virtual displays. Extension of this design to other resolutions and field of views is also explored.

Wells, Ben A.

1992-07-01

27

Mars high-resolution mapping  

NASA Technical Reports Server (NTRS)

A series of photomosaics of high-resolution Viking Orbiter images of Mars is being prepared and published to support the Mars 1:500,000 scale geologic mapping program. More than 100 of these photomosaics were made manually, but for the last several years they have all been made digitally. The digital mosaics are published on the Mars Transverse Mercator (MTM) system, and they are also available to the appropriate principal investigators as digital files in the mosaicked digital image model (MDIM) format. The mosaics contain Viking Orbiter images with the highest available resolution: in some areas as high as 10 m/pixel. This resolution, where it exists, will support a 1:100,000 map scale. The full resolution of a mosaic is preserved in a digital file, but conventional lithographic publication of such large-scale inset maps will be done only if required by the geologic map author. When high-resolution images do not full the neatlines of an MTM quadrangle, the medium-resolution (1/256 degrees/pixel, or 231 m/pixel) MDIM is used. The mosaics are tied by image-matching to the planetwide MDIM, in which random errors as large as 5 km (10 mm at 1:500,000 scale) are common; a few much larger, worst-case errors also occur. Because of the distribution of the errors, many large discrepancies appear along the cutlines between frames with very different resolutions. Furthermore, each block of quadrangles is compiled on its own local control system, and adjacent blocks, compiled later, are unlikely to match. Selection of areas to be mapped is based on geologic mapping proposals reviewed and recommended by the Mars 1:500,000 scale geologic mapping review panel. There is no intention to map the entire planet at this scale.

Batson, R. M.; Thomas, P. K.

1991-01-01

28

Image deconvolution in digital autoradiography  

PubMed Central

Digital autoradiography (DAR) is a powerful method to determine quantitatively the “small-scale” (i.e., submillimeter) distribution of a radiotracer within a tissue section. However, the limited spatial resolution of the DAR image, due to blurring by the point spread function (PSF), can result in a poor correlation with tissue histology and immunohistochemistry. The authors attempt to overcome this limitation by recovering the radiotracer distribution by image deconvolution using the Richardson-Lucy algorithm and a measured PSF obtained from a small radioactive source on hydrophobic microscope slide. Simulation studies have shown that the deconvolution algorithm reliably recovers the pixel values corresponding to the radioactivity distributions. As an example, the proposed image restoration approach has been tested with DAR images of different radiolabeled markers on tumor sections obtained from clinical and preclinical animal model studies. Digital autoradiograms following deconvolution show improved sharpness and contrast relative to the unprocessed autoradiograms.

Zhang, Mutian; Chen, Qing; Li, Xiao-Feng; O'Donoghue, Joseph; Ruan, Shutian; Zanzonico, Pat; Ling, C. Clifton; Humm, John L.

2009-01-01

29

High Resolution VHF Meteor Study.  

National Technical Information Service (NTIS)

High resolution, dual-frequency, VHF observations of meteors were conducted during 1964 and 1965 utilizing the DAZZLE radar at Central Bore, South Australia. An abridged description of the radar as it applies to these observations is given and full operat...

R. H. Todd

1966-01-01

30

High-pass resolution perimetry  

Microsoft Academic Search

Review of all available reports comparing high-pass resolution perimetry (HRP) and conventional perimetry in normals and in subjects with different visual disorders reveals closely comparable aspects of sensitivity, specificity, and reliability. HRP shows important advantages concerning variability, test duration, and subject preferences. Drawbacks seem largely limited to somewhat loose renditions of visual field defects of small area and large depth.

Lars FrisÉn

1993-01-01

31

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

32

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

33

High Resolution Time Interval Counter.  

National Technical Information Service (NTIS)

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 channel...

D. D. Davis M. A. Lombardi V. S. Zhang

1994-01-01

34

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

35

High resolution magnetic force microscopy  

NASA Astrophysics Data System (ADS)

Magnetic Force Microscopy (MFM) has become ubiquitous in both fundamental magnetics research and a variety of magnetic technologies. As would be expected for any microscopy there is a continuous push to increase the spatial resolution of MFM. We have used electron beam deposition (EBD) techniques to manufacture high resolution MFM tips. [1] These tips have sufficient resolution to image continuous magnetic field reversals on the order of 30nm (as opposed to the observation of isolated dipoles which can be accomplished with commercial MFM tips). We have used these tips to study the magnetic reversal in CoCr films with a perpendicular anisotropy using in situ applied magnetic fields MFM. This study has revealed partial magnetic reversal within Co rich grains and flux closure between grains. [2] In addition to this study, we have performed high resolution MFM and Landau Lifschitz Gilbert simulations of the magnetic domain structure in Ni dots with a perpendicular anisotropy. The magnetic state of a witness film can be characterized by a stripe domain pattern with a regular period for the magnetization reversal. In the dots, we are able to predict the magnetic state by comparing the dot diameter to the stripe period. [1] Skidmore et al., Appl. Phys. Lett. 71, 3293-95 (1997) [2]. Wastlbauer et al., Appl. Phys. Lett., to be published in Jan. 2000.

Dahlberg, E. Dan

2000-03-01

36

High resolution tomographic instrument development  

NASA Astrophysics Data System (ADS)

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 benefitted 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.

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

Mars high-resolution mapping  

Microsoft Academic Search

A series of photomosaics of high-resolution Viking Orbiter images of Mars is being prepared and published to support the Mars 1:500,000 scale geologic mapping program. More than 100 of these photomosaics were made manually, but for the last several years they have all been made digitally. The digital mosaics are published on the Mars Transverse Mercator (MTM) system, and they

R. M. Batson; P. K. Thomas

1991-01-01

40

High resolution AMS imaging of radiocarbon in biomedical applications  

NASA Astrophysics Data System (ADS)

Radiocarbon has been an important labelling element in biological metabolism studies. By interfacing an accelerator mass spectrometer (AMS) with a scanning microprobe secondary ion source, we have imaged the uptake of radiocarbon labelled metabolic or neurotransmitter amino acids by neurons and glial cells of rats and gerbils at high resolution (1 micron), high sensitivity and in a short time. The biological samples are prepared and sectioned serially at 0.5 ?m thickness using standard histological procedures. The adjacent sections to those used for AMS imaging were either immunolabelled with antibodies to GABA to reveal GABA-containing cells, or stained with toluidine blue to visualise every cell. Therefore, the distribution of radiocarbon revealed by AMS could be matched to that of the cells. By simultaneously measuring the 14C, 13C and 12C signals, we can demonstrate that the localised peaks of radiocarbon could be readily identified and matched to GABA-immunopositive neurons and glial cells by aligning the radiocarbon deficient blood vessels with the vessels in the adjacent histologically stained section. The results revealed the selective uptake of the neurotransmitter, GABA and that of metabolic amino acid, leucine. The technique compares favourably with high resolution autoradiography and provides great potential for improving the analysis of molecular interactions in and between cells.

Jiang, Z. X.; Bronk Ramsey, C.; Hedges, R. E. M.; Somogyi, P.; Roberts, J. D. B.; Cowey, A.

1997-03-01

41

Autoradiography, MALDI-MS, and SIMS-MS Imaging in Pharmaceutical Discovery and Development  

Microsoft Academic Search

Whole-body autoradiography ((WBA) or quantitative WBA (QWBA)), microautoradiography (MARG), matrix-assisted laser desorption\\/ionization\\u000a mass spectrometric imaging (MALDI-MSI), and secondary ion mass spectrometric imaging (SIMS-MSI) are high-resolution, molecular\\u000a imaging techniques used to study the tissue distribution of radiolabeled and nonlabeled compounds in ex vivo, in situ biological samples. WBA, which is the imaging of the whole-body of lab animals, and\\/or their organ

Eric G. Solon; Alain Schweitzer; Markus Stoeckli; Brendan Prideaux

2010-01-01

42

High resolution time interval counter  

DOEpatents

A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured.

Condreva, Kenneth J. (Livermore, CA)

1994-01-01

43

High resolution time interval counter  

DOEpatents

A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured. 3 figs.

Condreva, K.J.

1994-07-26

44

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

45

Method for creating high resolution print media  

US Patent & Trademark Office Database

A method for creating a high resolution print media using a display resolution screen image approval process, web-based ordering, web based checkout and payment, by an unskilled user to create a message of pre-process data and a display resolution image for rendering a high resolution image on a substrate.

2014-04-22

46

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

47

High-resolution breast ultrasonography.  

PubMed

Recent improvements in ultrasonic-scanning now permit solid tumors in the breast as small as 5 mm and cystic lesions of 2mm in size to be detected. The overall accuracy of diagnostic ultrasound is very high, and as more experience is gained by application of newer high-resolution systems this accuracy will improve even further. In certain cases, ultrasonography can detect lesions completely missed by clinical palpation. In some areas such as cystic lesions this modality is far superior to the mammograph and in other situations it complements other diagnostic procedures. Areas of microcalcification may be localized. Cystic lesions of the breast are not easily diagnosed with great accuracy. In our extensive experience over the past 4 years, fibroadenomas generally appear as sharply marginated spherical or lobulated masses with an echopoor center and high through transmission. Carcinoma tends to attenuate sound energy highly and frequently produces a characteristic echo pattern. Fibrous dysplasia appears as a highly echogenic zone which is readily distinguished from other entities. Contact ultrasonography is used to localize the lesion three-dimensionally within the breast for biopsy purposes and to detect the presence of distant metastases. PMID:7215116

Hassani, S N; Bard, R L; Flynn, G S

1980-01-01

48

High resolution, high speed ultrahigh vacuum microscopy  

SciTech Connect

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 [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2004-09-01

49

High resolution polarimetric FMCW radar  

Microsoft Academic Search

The Monash FMCW radar has been successful in detecting and locating defects in natural and man-made dielectrics (eg. defects in sawmill wood), with a range resolution, of 2 cm in wood. The authors show how to improve this resolution and provide polarimetric capability, which is important in anisotropic and optically active materials. The large bandwidth requirement has required a redefinition

A. Z. Tirkel; C. F. Osborne

1993-01-01

50

High resolution optoelectronic retinal prosthesis  

NASA Astrophysics Data System (ADS)

Electronic retinal prostheses seek to restore sight in patients with retinal degeneration by delivering pulsed electric currents to retinal neurons via an array of microelectrodes. Most implants use inductive or optical transmission of information and power to an intraocular receiver, with decoded signals subsequently distributed to retinal electrodes through an intraocular cable. Surgical complexity could be minimized by an "integrated" prosthesis, in which both power and data are delivered directly to the stimulating array without any discrete components or cables. We present here an integrated retinal prosthesis system based on a photodiode array implant. Video frames are processed and imaged onto the retinal implant by a video goggle projection system operating at near-infrared wavelengths (~ 900 nm). Photodiodes convert light into pulsed electric current, with charge injection maximized by specially optimized series photodiode circuits. Prostheses of three different pixel densities (16 pix/mm2, 64 pix/mm2, and 256 pix/mm2) have been designed, simulated, and prototyped. Retinal tissue response to subretinal implants made of various materials has been investigated in RCS rats. The resulting prosthesis can provide sufficient charge injection for high resolution retinal stimulation without the need for implantation of any bulky discrete elements such as coils or tethers. In addition, since every pixel functions independently, pixel arrays may be placed separately in the subretinal space, providing visual stimulation to a larger field of view.

Loudin, Jim; Dinyari, Rostam; Huie, Phil; Butterwick, Alex; Peumans, Peter; Palanker, Daniel

2009-02-01

51

High-resolution infrared imaging  

NASA Astrophysics Data System (ADS)

The hands and mind of an artist are intimately involved in the creative process of image formation, intrinsically making paintings significantly more complex than photographs to analyze. In spite of this difficulty, several years ago the artist David Hockney and I identified optical evidence within a number of paintings that demonstrated artists began using optical projections as early as c1425 - nearly 175 years before Galileo - as aids for producing portions of their images. In the course of our work, Hockney and I developed insights that I have been applying to a new approach to computerized image analysis. Recently I developed and characterized a portable high resolution infrared for capturing additional information from paintings. Because many pigments are semi-transparent in the IR, in a number of cases IR photographs ("reflectograms") have revealed marks made by the artists that had been hidden under paint ever since they were made. I have used this IR camera to capture photographs ("reflectograms") of hundreds of paintings in over a dozen museums on three continents and, in some cases, these reflectograms have provided new insights into decisions the artists made in creating the final images that we see in the visible.

Falco, Charles M.

2010-08-01

52

Planetary Atmospheres at High Resolution  

NASA Astrophysics Data System (ADS)

The long millimeter through submillimeter bands are particularly well suited for studying the wide variety of planetary atmospheres in our solar system. Temperatures ranging from a few 10s to hundreds of degrees, coupled with typically high densities (relative to the ISM) mean that thermal ‘continuum’ emission can be strong and molecular rotational transitions can be well-populated. Large bodies (Jovian and terrestrial planets) can be reasonably well studied by current interferometers such as the Submillimeter Array, IRAM Plateau de Bure Interferometer, and Combined Array for Research in Millimeter-wave Astronomy, yet many smaller bodies with atmospheres can only be crudely studied, primarily due to lack of sensitivity on baselines long enough to well resolve the object. Newly powerful interferometers such as the Atacama Large Millimeter/Submillimeter Array will usher in a new era of planetary atmospheric exploration. The vast sensitivity and spatial resolution of these arrays will increase our ability to image all bodies with extremely fine fidelity (due to the large number of antennas), and for study of smaller objects by resolving their disks into many pixels while providing the sensitivity necessary to detect narrow and/or weak line emission. New science topics will range from detailed mapping of HDO, ClO, and sulfur species in the mesosphere of Venus and PH3 and H2S in the upper tropospheres of the gas and ice giants, high SNR mapping of winds on Mars, Neptune and Titan, down to spectroscopic imaging of volcanic eruptions within the tenuous atmosphere on Io, resolved imaging of CO and other species in the atmosphere of Pluto, and even potentially detection of gases within the plumes of Enceladus.

Gurwell, M.; Butler, B.; Moullet, A.

2013-10-01

53

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

54

High resolution RR interval measurement  

Microsoft Academic Search

R-R interval measurement from digitized ECG signal has an inherent error due to the finite sampling frequency. This error causes distortion of heart rate variability (HRV) power spectrum. Results of implementation of an algorithm designed to increase the resolution of R-R interval measurement are reported. The algorithm first estimates the R-R intervals with a finite resolution accuracy. Then the interval

T. Harel; S. A. Ben-Haim; I. Gath

1993-01-01

55

Signal processing in a high resolution radar  

Microsoft Academic Search

Theory and signal processing of a high resolution radar with a time-bandwidth-product of about 1 million are presented. Limits of range-resolution of two scatterers with unknown distance are described by means of a statistical theory of resolution. The corresponding resolution-filter results in the conventional matched filter for the limiting case of a delta impulse autocorrelation function of the radar signal.

K. Kruecker; D. Perkuhn

1977-01-01

56

High Resolution Satellite Image Orientation Models  

Microsoft Academic Search

\\u000a A few years ago high resolution satellite imagery became available to a limited number of government and defense agencies\\u000a that managed such imagery with highly sophisticated software and hardware tools. Such images became available to civil users\\u000a in 1999 with the launch of Ikonos, the first civil satellite offering a spatial resolution of 1 m. Since then other high resolution

Mattia Crespi; Francesca Fratarcangeli; Francesca Giannone; Francesca Pieralice

57

High resolution laser imaging system.  

PubMed

Computations indicate that a synthetic aperture laser imaging system can provide images with 10-cm resolution at satellite ranges using a 10-W cw laser. When imaging satellites from the ground, the synthetic aperture system reduces atmospheric degradations. The system uses 20-cm diam receiver optics. The low laser power is made possible by using separate transmitter and receiver optics and coded pulses with a 50% transmitter duty cycle. The coded pulses are derived from Hadamard matrices for which there is an efficient algorithm to transform the received data into images. The synthetic aperture yields spatial resolutions independent of range, and the coded pulses result in an effective range dependence of r(-2)2 instead of r(-4). PMID:20555574

Kyle, T G

1989-07-01

58

High-resolution mapping of satellite DNA using biotin-labeled DNA probes  

PubMed Central

We have developed a novel method for high resolution mapping of specific DNA sequences after in situ hybridization. DNA probes, labeled with biotin-nucleotides in conventional nick-translation reactions, are hybridized to cytological preparations and detected with affinity- purified rabbit antibiotin antibodies followed by antibodies to rabbit IgG that are conjugated to fluorescent or enzymatic reagents. Using peroxidase labeled anti-rabbit IgG, we are able to detect and localize specific sequences at both the light and electron microscopic levels. Initial studies were done with repeated DNA sequences previously mapped by light microscope autoradiography to assess the fidelity and resolution of this method. An analysis using biotin-labeled mouse satellite DNA is presented here.

1982-01-01

59

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

60

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.

Street, Robert A. (Palo Alto, CA); Kaplan, Selig N. (El Cerrito, CA); Perez-Mendez, Victor (Berkeley, CA)

1992-01-01

61

High Resolution PDF Measurements on Ag Nanoparticles  

SciTech Connect

The quantitative analysis of structural defects in Ag nanoparticles was addressed in this work. We performed atomic scale structural characterization by a combination of x-ray diffraction (XRD) using the Pair Distribution Function analysis (PDF) and High Resolution Transmission Electron Microscopy (HRTEM). The XRD measurements were performed using an innovative instrumentation setup to provide high resolution PDF patterns.

Rocha, Tulio C. R. [Brazilian Synchrotron Light Laboratory, Laboratorio Nacional de Luz Sincrotron Sincrotron, CP 6192, 13083-971, Campinas SP (Brazil); Universidade Estadual de Campinas (Brazil); Martin, Chris; Kycia, Stefan [University of Guelph (Canada); Zanchet, Daniela [Brazilian Synchrotron Light Laboratory, Laboratorio Nacional de Luz Sincrotron Sincrotron, CP 6192, 13083-971, Campinas SP (Brazil)

2009-01-29

62

High resolution scintillation detector with semiconductor readout  

DOEpatents

A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

Levin, Craig S. (Santa Monica, CA); Hoffman, Edward J. (Los Angeles, CA)

2000-01-01

63

High resolution spectrograph for the Space Telescope  

Microsoft Academic Search

The high resolution spectrograph (HRS) for ultraviolet astronomy with the Space Telescope will provide a spectral resolution of approximately 120,000 over a nominal wavelength range of 110-320 nm, together with a spatial resolution of about 0.25 arc seconds. The two detectors will consist of 512-element Digicons with cesium telluride and cesium iodide photocathodes, respectively. Photoelectrons in transit between the photocathodes

J. C. Brandt; A. Boggess; S. R. Heap; S. P. Maran; A. M. Smith; E. A. Beaver; M. Bottema; J. B. Hutchings; M. A. Jura; J. L. Linsky

1979-01-01

64

SQUID-based high-resolution thermometer  

NASA Astrophysics Data System (ADS)

High-resolution thermometers (HRTs) based on the detection of magnetization changes of a magnetic material using very sensitive superconducting quantum interference device (SQUID) have routinely achieved temperature resolution of 0.1 nK/ Hz at temperatures below 4 K in several laboratories. The resolution of these thermometers has reached the fundamental limit imposed by thermodynamic fluctuations. The principle of operation as well as the theory of the noise are presented. Some recent discoveries using HRT are discussed.

Chui, Talso C. P.

2001-05-01

65

High Resolution TEM Imaging in Ferromagnetic Fe.  

National Technical Information Service (NTIS)

The techniques used to obtain high resolution TEM images of ferromagnetic (bcc) Fe specimens with a JEOL JEM-100 CX microscope are presented. Realignment of the electron optics with the specimen in place gives a resolution of approx. 5 A point-to-point at...

D. M. Follstaedt

1982-01-01

66

High-Resolution Radar via Compressed Sensing  

Microsoft Academic Search

ADAR, sonar and similar imaging systems are in high demand in many civilian, military, and biomedical appli- cations. The resolution of these systems is limited by classical time-frequency uncertainty principles. Using the concepts of compressed sensing, we propose a radically new approach to radar, which under certain conditions provides better time- frequency resolution. In this simplified version of a monostatic,

Matthew A. Herman; Thomas Strohmer

2008-01-01

67

High resolution laser spectroscopy of atomic hydrogen  

Microsoft Academic Search

It is speculated that in the near future very stringent tests of basic physics laws will become possible based on very high resolution laser spectroscopy of atomic hydrogen. By cooling hydrogen atoms below liquid helium temperature, two-photon optical Ramsey spectroscopy will be possible with a resolution of better than 1 part in 1015. (AIP)

R. G. Beausoleil; B. Couillaud; C. J. Foot; E. A. Hildum; D. H. McIntyre

1986-01-01

68

18 F-choline in experimental soft tissue infection assessed with autoradiography and high-resolution PET  

Microsoft Academic Search

For each oncological tracer it is important to know the uptake in non-tumorous lesions. The purpose of this study was to measure the accumulation of fluorine-18 choline (FCH), a promising agent for the evaluation of certain tumour types, in infectious tissue. Unilateral thigh muscle abscesses were induced in five rats by intramuscular injection of 0.1 ml of a bacterial suspension (

Matthias T. Wyss; Bruno Weber; Michael Honer; Nicolas Späth; Simon M. Ametamey; Gerrit Westera; Beata Bode; Achim H. Kaim; Alfred Buck

2004-01-01

69

Quantitative High Resolution Electron Scattering From Polymers.  

National Technical Information Service (NTIS)

This project developed and applied quantitative methods to determine the structure of polymers and polymer-based materials using high spation resolution electron-scattering techniques. The traditional approach to studying polymer morphology using the elec...

M. R. Libera

2004-01-01

70

High-Resolution Preparative Liquid Chromatography.  

National Technical Information Service (NTIS)

Researchers focused on the development of high-resolution preparative liquid chromatography. Novel column packing materials with low compression ratios and small operating pressure drop were discovered. The most promising of these are oriented fibers and ...

R. D. Schwartz

1990-01-01

71

Electronics Upgrade of High Resolution Mass Spectrometers.  

National Technical Information Service (NTIS)

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 labora...

J. Cordaro J. Mcintosh

2008-01-01

72

High Resolution Optical Power Spectrum Analyzer.  

National Technical Information Service (NTIS)

The High Resolution Optical Power Spectrum Analyzer (HOPS) was conceived as a better approach to a large volume optical power spectrum (OPS) scanning of imagery. This approach enables conventional OPS measurement coupled with simplified parallel optical f...

N. Balasubramanian P. S. Considine

1978-01-01

73

High resolution technology for FPD lithography tools  

NASA Astrophysics Data System (ADS)

As the resolution of LCD panels adapted for Smartphone and Tablet PC rapidly becomes higher, the performance needed for lithography tools to produce them also becomes higher than ever. To respond to such needs, we have developed new lithography tools for mass production of high resolution LCD panels. We have executed various exposure tests to evaluate their performance. In this paper, we present the results of these tests. By employing higher NA projection optics, high resolution (2.0?m and under) has been achieved. We also present the effect of special illumination and the difference in profile between kinds of photoresist. Furthermore, we also refer what will be needed for masks and blanks in the next generation. To achieve even higher resolution, it is necessary for masks and blanks to have high flatness, low level of defects and small linewidth error.

Yabu, Nobuhiko; Nagai, Yoshiyuki; Tomura, Satoshi; Yoshikawa, Tomohiro

2013-06-01

74

Fast high-resolution tomographic spectrometry  

SciTech Connect

A tomographic spectral apparatus is described which makes possible measurements in the fast multipass monochromator or single-pass polychromator regimes. The device is constructed using a highly focusing astigmatic monochromator and an electrostatic dissector. High spectral and temporal resolutions are obtained along with relatively small dimensions and high sensitivity. 6 refs.

Veklich, A.N.; Zhovtyanskii, V.A. [T.G. Shevchenko State Univ., Kiev (Ukraine); Kaidalov, S.A.; Pchelov, E.M. [All-Union Scientific-Research Institute for Physical Optics Measurements, Moscow (Russian Federation)

1992-02-01

75

X-ray holography with high resolution  

SciTech Connect

Some primary factors having effects on the resolution in x-ray holography are discussed. The factors in recording x-ray holograms are the x-ray coherent scattering by the specimen, the recording method and the coherence of the x-ray beam. There are two factors in reconstruction of the hologram. One is that the resolution of the detector may be lower than the spatial frequencies of fringes in x-ray holograms. The other is aberrations. Consequently, some conditions of x-ray holography with high resolution are given.

Chen Jianwen; Zhu Peiping; Xiao Tiqiao; Xu Zhizhan [Shanghai Institute of Optics and Fine Mechanics, Academia Sinica, P. O. Box 800216, Shanghai, 201800 (China)

1995-05-01

76

High resolution TEM imaging in ferromagnetic Fe  

SciTech Connect

The techniques used to obtain high resolution TEM images of ferromagnetic (bcc) Fe specimens with a JEOL JEM-100 CX microscope are presented. Realignment of the electron optics with the specimen in place gives a resolution of approx. 5 A point-to-point at 120 keV as demonstrated with images of small (approx. 10 A) He bubbles in Fe. The use of a special pole piece designed to minimize the objective lens magnetic field at the specimen is also discussed.

Follstaedt, D.M.

1982-09-01

77

High-Resolution Radar Imagery of Mars  

Microsoft Academic Search

We present high-resolution radar images of Mars obtained during the 2005 and 2007 oppositions. The images were constructed from long-code delay-Doppler observations made with the Arecibo S-band (13-cm) radar. The average image resolution of 3 km represented a better than order-of-magnitude improvement over pre-upgrade Arecibo imagery of the planet. Images of depolarized reflectivity (an indicator primarily of wavelength-scale surface roughness)

John K. Harmon; M. C. Nolan

2009-01-01

78

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

79

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

80

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

81

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

82

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

83

KRAS: A Danish high resolution airborne SAR  

NASA Astrophysics Data System (ADS)

A C-band high resolution airborne synthetic aperture radar (SAR) is presently being constructed. The main purpose of the project, which is called KRAS, is to develop the knowledge base required to build advanced coherent radars. The design rationale is presented. The design of the radar is based on digital technology to the largest possible degree. This results in a very flexible radar system, with most of the system parameters being software controlled. Variable waveforms of bandwidths larger than 100 MHz and durations up to 20 microsec can be generated. Calibration of the system was also given much consideration, and design principles usually applied in radiometers were implemented. The significant flexibility and the calibration is of major importance since the system is intended for applications ranging from medium resolution wide swath mapping, i.e., sea ice mapping or oil pollution surveillance, to high resolution narrow swath mapping for cartography or reconnaissance.

Madsen, Soren Norvang; Christensen, Erik Lintz; Skou, Niels

1989-01-01

84

High resolution photoelectron imaging of Au2-  

NASA Astrophysics Data System (ADS)

We report high resolution photoelectron spectra of Au2- using a newly built photoelectron imaging apparatus. Vibrationally resolved photoelectron images are obtained for the ground state detachment transition of Au2- at various photon energies (442.80-670.18 nm) at a resolution of 3 cm-1 for low energy electrons. Franck-Condon simulations yield the vibrational temperature of Au2- and the high resolution data yield accurate spectroscopic constants for the ground states of Au2 and Au2-. The electron affinity of Au2 is measured to be 1.9393 +/- 0.0006 eV. A more precise value for the Au2- dissociation energy is also obtained as 1.937 +/- 0.005 eV.

León, Iker; Yang, Zheng; Wang, Lai-Sheng

2013-05-01

85

High resolution photoelectron imaging of Au2(-).  

PubMed

We report high resolution photoelectron spectra of Au2(-) using a newly built photoelectron imaging apparatus. Vibrationally resolved photoelectron images are obtained for the ground state detachment transition of Au2(-) at various photon energies (442.80-670.18 nm) at a resolution of 3 cm(-1) for low energy electrons. Franck-Condon simulations yield the vibrational temperature of Au2(-) and the high resolution data yield accurate spectroscopic constants for the ground states of Au2 and Au2(-). The electron affinity of Au2 is measured to be 1.9393 ± 0.0006 eV. A more precise value for the Au2(-) dissociation energy is also obtained as 1.937 ± 0.005 eV. PMID:23676041

León, Iker; Yang, Zheng; Wang, Lai-Sheng

2013-05-14

86

High-Resolution Model of the Microtubule  

Microsoft Academic Search

A high-resolution model of the microtubule has been obtained by docking the crystal structure of tubulin into a 20 Å map of the microtubule. The excellent fit indicates the similarity of the tubulin conformation in both polymers and defines the orientation of the tubulin structure within the microtubule. Long C-terminal helices form the crest on the outside of the protofilament,

Eva Nogales; Michael Whittaker; Ronald A. Milligan; Kenneth H. Downing

1999-01-01

87

High Resolution Sea Surface Temperature Field Derived.  

National Technical Information Service (NTIS)

A procedure for deriving high resolution sea surface temperature field from digital AVHRR/HRPT data is described. For the purpose of reducing the processing time, only the reflective threshold or near infrared channel is used for selecting data over clear...

S. Zhou W. Chen L. Zhang

1986-01-01

88

Clementine High Resolution Camera Mosaicking Project.  

National Technical Information Service (NTIS)

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...

1998-01-01

89

Sparse and accurate high resolution SAR imaging  

NASA Astrophysics Data System (ADS)

We investigate the usage of an adaptive method, the Iterative Adaptive Approach (IAA), in combination with a maximum a posteriori (MAP) estimate to reconstruct high resolution SAR images that are both sparse and accurate. IAA is a nonparametric weighted least squares algorithm that is robust and user parameter-free. IAA has been shown to reconstruct SAR images with excellent side lobes suppression and high resolution enhancement. We first reconstruct the SAR images using IAA, and then we enforce sparsity by using MAP with a sparsity inducing prior. By coupling these two methods, we can produce a sparse and accurate high resolution image that are conducive for feature extractions and target classification applications. In addition, we show how IAA can be made computationally efficient without sacrificing accuracies, a desirable property for SAR applications where the size of the problems is quite large. We demonstrate the success of our approach using the Air Force Research Lab's "Gotcha Volumetric SAR Data Set Version 1.0" challenge dataset. Via the widely used FFT, individual vehicles contained in the scene are barely recognizable due to the poor resolution and high side lobe nature of FFT. However with our approach clear edges, boundaries, and textures of the vehicles are obtained.

Vu, Duc; Zhao, Kexin; Rowe, William; Li, Jian

2012-05-01

90

High resolution spectroscopy from low altitude satellites  

Microsoft Academic Search

The P 78 1 satellite to be placed in a synchronous polar orbit at an altitude of 550-660 km will carry two identical high resolution spectrometers each consisting of a single (approximately 85 cc) intrinsic germanium IGE detector. The payload also includes a pair of phoswitch scintillators, an array of CdTe detectors and several particle detectors, all of which are

G. H. Nakano; W. L. Imhof

1978-01-01

91

High Resolution Sensor for Nuclear Waste Characterization  

Microsoft Academic Search

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

Kanai Shah; William Higgins; Edgar V. Van Loef

2006-01-01

92

A High-Resolution Stopwatch for Cents  

ERIC Educational Resources Information Center

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

Gingl, Z.; Kopasz, K.

2011-01-01

93

High resolution cytogenetic study in schizophrenia.  

PubMed

A high resolution cytogenetic study was performed on forty unrelated schizophrenic patients defined by DSM-III-R criteria. We have not included cases with mental retardation, severe dysmorphic features or other characteristic symptoms of chromosomal syndromes in our analysis. No recognizable chromosomal abnormality was found. PMID:8839886

Casacchia, M; Brisdelli, F; de Cataldo, S; Rossi, A; d'Alessandro, E

1996-01-01

94

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

95

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

96

Scanning Transmission Electron Microscopy at High Resolution  

PubMed Central

We have shown that a scanning transmission electron microscope with a high brightness field emission source is capable of obtaining better than 3 Å resolution using 30 to 40 keV electrons. Elastic dark field images of single atoms of uranium and mercury are shown which demonstrate this fact as determined by a modified Rayleigh criterion. Point-to-point micrograph resolution between 2.5 and 3.0 Å is found in dark field images of micro-crystallites of uranium and thorium compounds. Furthermore, adequate contrast is available to observe single atoms as light as silver. Images

Wall, J.; Langmore, J.; Isaacson, M.; Crewe, A. V.

1974-01-01

97

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

98

High resolution electron crystallography of protein molecules  

SciTech Connect

Electron diffraction data and high resolution images can now be used to obtain accurate, three-dimensional density maps of biological macromolecules. These density maps can be interpreted by building an atomic-resolution model of the structure into the experimental density. The Cowley-Moodie formalism of dynamical diffraction theory has been used to validate the use of kinematic diffraction theory, strictly the weak phase object approximation, in producing such 3-D density maps. Further improvements in the preparation of very flat specimens and in the retention of diffraction to a resolution of 0.2 nm or better could result in electron crystallography becoming as important a technique as x-ray crystallography currently is for the field of structural molecular biology.

Glaeser, R.M. [California Univ., Berkeley, CA (United States). Dept. of Molecular and Cell Biology]|[Lawrence Berkeley Lab., CA (United States); Downing, K.H. [Lawrence Berkeley Lab., CA (United States)

1993-06-01

99

Constructing a WISE High Resolution Galaxy Atlas  

NASA Astrophysics Data System (ADS)

After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 ?m, 4.6 ?m, 12 ?m, and 22 ?m. 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.; Sheth, K.; Stanford, S.; Wright, E.

2012-08-01

100

Supernova Remnant 1987A at High Resolution  

NASA Astrophysics Data System (ADS)

We present high resolution radio and X-ray observations of supernova remnant 1987A. VLBI imaging at 1.4 and 1.7 GHz taken in 2007 and 2008 with the Australian Long Baseline Array provides the highest resolution radio images of the remnant to date, revealing two extended lobes with an overall morphology consistent with observations at lower resolutions. We find evidence of small-scale features in the radio remnant, which possibly consist of discrete clumps near the inner surface of the shell. These features have spatial extent smaller than 0.2" and contribute less than 13% of the total remnant flux. We also report new X-ray observation taken in 2010 August with the High Resolution Camera onboard the Chandra X-ray Observatory. Comparing to the 2008 April exposure with the same instrument, the remnant flux increased by 43% in the 0.08-10 kev range and the relative brightness of the X-ray lobes around the shell show significant variability. In particular, the western half of shell is now 15% brighter than the eastern half. No central compact object is found in the radio and X-ray images. We compare the detection limits to previous studies and discuss the physical implications. The Australia Long Baseline Array is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

Ng, Chi-Yung; Potter, T. M.; Staveley-Smith, L.; Gaensler, B. M.; Murray, S. S.; Tingay, S.; Phillips, C.; Tzioumis, A. K.; Zanardo, G.

2011-01-01

101

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

102

Compact high-resolution spectral phase shaper  

SciTech Connect

The design and operation of a high-resolution spectral phase shaper with a footprint of only 7x10 cm{sup 2} is presented. The liquid-crystal modulator has 4096 elements. More than 600 independent degrees of freedom can be positioned with a relative accuracy of 1 pixel. The spectral shaping of pulses from a broadband Ti:sapphire laser is verified by a hybrid cross-frequency-resolved optical gating/Grenouille measurement and intensity autocorrelation. We demonstrate the ability to split one pulse into two or more pulses with a programmable delay of more than 8.5 ps. To our knowledge this represents the most compact high resolution device in liquid-crystal modulator-based shaping to this date.

Postma, S.; Walle, P. van der; Offerhaus, H.L.; Hulst, N.F. van [Applied Optics Group, Department of Science and Technology, MESA Institute for Nanotechnology, University of Twente, Enschede (Netherlands)

2005-12-15

103

The other high resolution post accelerator approach  

SciTech Connect

There has been significant discussion in consideration of a high resolution mass separator followed by a RFQ and a linear accelerator as the basic format for IsoSpin Laboratory. There exists another strong possibility-namely a low-resolution mass separator coupled to a cyclotron. The major objection to this approach has been that the conversion from the +1 mass separator beam to a q/m beam of 1/4 to 1/3 is thought to be highly inefficient. Since we are in the fortunate position of having the two expensive components of this system available for tests (an on-line mass separator and an ECR source), we intend to couple these devices to actually measure these efficiencies and to test ideas for improving the efficiency. We present some specifics of this approach.

Moltz, D.M.; Tighe, R.J.; Rowe, M.W.; Ognibene, T.J.; Cerny, J.

1993-05-24

104

High Resolution Mirror Assembly: The Assembly Challenges  

NASA Astrophysics Data System (ADS)

During the integration of the High Resolution Mirror Assembly (HRMA), a continuous learning process was adopted. Each step in the process provided critical insight into how the future assembly would operate. Process development was on-going as more was learned during the assembly effort at ITT. This poster will provide a overview of the lessons learned and the process development that took place to enable the HRMA to meet all performance criteria on-orbit.

Matthews, Gary; Atkinson, Charlie

2009-09-01

105

The first high-resolution DNA "methylome".  

PubMed

Cytosine methylation plays a crucial role in the regulation of gene expression and the control of genome stability in higher eukaryotes. Despite its importance for normal development, the degree and genome-wide distribution of DNA methylation has remained largely unknown. In this issue of Cell, fill this gap by presenting a high-resolution map of DNA methylation in the genome of the flowering plant Arabidopsis. PMID:16990127

Schöb, Hanspeter; Grossniklaus, Ueli

2006-09-22

106

High spatial resolution passive microwave sounding systems  

NASA Technical Reports Server (NTRS)

Two extensive series of flights aboard the ER-2 aircraft were conducted with the MIT 118 GHz imaging spectrometer together with a 53.6 GHz nadir channel and a TV camera record of the mission. Other microwave sensors, including a 183 GHz imaging spectrometer were flown simultaneously by other research groups. Work also continued on evaluating the impact of high-resolution passive microwave soundings upon numerical weather prediction models.

Staelin, D. H.; Rosenkranz, P. W.; Bonanni, P. G.; Gasiewski, A. W.

1986-01-01

107

High-resolution modeling of regional phases  

Microsoft Academic Search

We present a series of techniques developed to decouple source phenomena from propagation effects by modeling regional phases with high resolution. Our trial-and-error approach to obtain 1-D crustal models and 1-D Green's functions is summarized in a set of sensitivity tests, where regional seismograms are decomposed into segments so that the impact of model parameters on each segment is the

Xi Song

1997-01-01

108

High resolution spectroscopy with novel nonlinear devices  

Microsoft Academic Search

Efficient frequency mixing in new non-linear materials, like periodically-poled (PP) crystals, is actually opening new spectral windows to high resolution spectroscopy. This provides additional degrees of freedom for an appropriate selection of the transitions to investigate. Difference frequency generation of radiation in PP-LiNbO3, at a wavelength tunable around 4.3 ?m, has proven to be an extremely sensitive tool for CO2

P. De Natale; P. Cancio; D. Mazzotti; G. Giusfredi; N. Picque

2000-01-01

109

High resolution spectrograph for the Space Telescope  

NASA Technical Reports Server (NTRS)

The high resolution spectrograph (HRS) for ultraviolet astronomy with the Space Telescope will provide a spectral resolution of approximately 120,000 over a nominal wavelength range of 110-320 nm, together with a spatial resolution of about 0.25 arc seconds. The two detectors will consist of 512-element Digicons with cesium telluride and cesium iodide photocathodes, respectively. Photoelectrons in transit between the photocathodes and the diodes within the Digicons can be deflected in two axes with 12-bit resolution. This feature facilitates a design that emphasizes reliability since (once a hermetic seal is opened in orbit), only two moving parts, a grating carrousel and a shutter, are required for regular operation of the HRS. The instrument will be controlled by a computer in the spacecraft. The scientific objectives of the HRS investigation relate to interstellar matter in our own and nearby galaxies, physical processes of stellar mass loss and mass transfer, chemical abundances, bright quasars and Seyfert galaxy nuclei, and solar system phenomena.

Brandt, J. C.; Boggess, A.; Heap, S. R.; Maran, S. P.; Smith, A. M.; Beaver, E. A.; Bottema, M.; Hutchings, J. B.; Jura, M. A.; Linsky, J. L.

1979-01-01

110

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

111

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

112

High resolution infrared image reconstruction using multiple, low resolution, aliased frames  

Microsoft Academic Search

Staring infrared detectors often produce low resolution images. This problem arises simply because the technology does not exist to produce higher resolution arrays with sufficient spatial sampling intervals. A proven approach to combat this difficulty involves recording multiple frames that have been optically shifted onto a high-resolution grid pattern and then combined together into a single high resolution image. This

E. A. Kaltenbacher; Russell C. Hardie

1996-01-01

113

High-Resolution Mapping in Manus Basin  

NASA Astrophysics Data System (ADS)

Near-bottom seafloor mapping with precisely navigated deep submergence vehicles has become increasingly common in a range of oceanographic settings. Recent mapping efforts at deep-water hydrothermal vent sites have resulted in high-resolution (sub-meter) bathymetry datasets that can be used to identify morphological features associated with volcanic, tectonic, and hydrothermal processes. The resolution of these maps, and our ability to accurately quantify the complex morphologic details of hydrothermal structures has been limited by a number of variables including navigational accuracy, sonar settings (e.g. acoustic wavelength, sonar orientation, ping rate), survey parameters (e.g. altitude, speed), data density, and data processing techniques (e.g. gridding algorithms). We present the results of two near-bottom surveys conducted in August 2006 at the PACMANUS (Papua New Guinea-Australia-Canada Manus) hydrothermal field in the eastern Manus Basin of the Bismarck Sea, south of New Ireland, Papua New Guinea. Data were simultaneously acquired with two high-resolution multibeam sonar systems mounted on the Remote Operated Vehicle (ROV) Jason 2. A Simrad SM2000 (200 kHz) multibeam system was mounted in down-looking mode, and an Imagenex DeltaT (675 kHz) multibeam system was mounted on the brow of the vehicle in a forward-looking orientation. Surveys were conducted in parallel survey lines at 15 m altitude (15 m line spacing), and the can be used to generate sub-meter resolution maps of the seafloor. The maps were assembled using a terrain registration algorithm designed to minimize the affects of navigation error. Together, these sonars provide a complementary dataset that allows us to better quantify the 3-dimensional morphological characteristics of complex hydrothermal vent structures. This information can be used to more accurately estimate the volume of hydrothermal deposits, and render a more complete environmental picture that is less hindered by occlusions and poor sonar coverage in highly complex terrain.

Roman, C. N.; Ferrini, V. L.

2006-12-01

114

A new approach to high resolution FISH  

SciTech Connect

Various gene mapping efforts need high resolution ordering of clones. Using fluorescence in situ hybridization (FISH) best resolution has so far been achieved by the methods where the cells have been lysed and the chromatin has been stretched on the slide. This original DIRVISH method can resolve probes located only a few kilobases apart. We describe here another, novel alternative for high resolution FISH mapping. In this method agarose embedded DNA in form of a pulse field gel block is used as a hybridization target. This target is easy to prepare and available in many laboratories dealing with positional cloning. A small piece of PFGE block is melted on a microscope slide, the DNA is stretched and air-dried. In addition to the technical simplicity of the method it also offers possibilities for pretreatments of the target DNA such as cleavage by rare cutting restriction enzymes. The modification has significantly improved the reproducibility, hybridization efficiency and quality of hybridization signals in the stretched DNA. In practice this method has been applied in positional cloning of genes behind two variants of neuronal lipofuscinosis (INCL, Chr 1p and vINCL, Chr 13q). Here we have successfully ordered YACs, cosmid, phage and plasmid clones on genomic DNA facilitating rapid construction of physical maps of the two areas. DNA released from YAC-blocks has also been used as target for ordering cosmid and phage clones within the YAC.

Heiskanen, M.A.; Karhu, R.; Hellsten, E. [National Public Health Institute, Helsinki (Finland)] [and others

1994-09-01

115

PFSS Models and High-Resolution Magnetograms  

NASA Astrophysics Data System (ADS)

Traditionally, Potential Field Source Surface (PFSS) models have used low-degree spherical harmonic transforms to calculate magnetic fields and estimate the large-scale coronal structure. This has been for two reasons; first, low-resolution data restricted the maximum degree of the transforms and second, the global magnetic structures of interest only required a low-degree expansion due to their distance from the photosphere. One of the most important applications of PFSS models has been to determine where open coronal field lines intersect the photosphere. However, the magnetic field near the solar surface is far more structured than can be accurately described by low-degree models. The combination of PFSS models capable of high-degree transforms and data from high-resolution solar imaging facilities is required to accurately determine the photospheric foot-point locations of coronal field lines. We present preliminary results from a new PFSS model that is capable of matching the spatial resolution of the MDI synoptic magnetograms used as input. We compare results to lower-degree models, and show how variations in the maximum spherical harmonic degree (l>1000) affect field line locations at the photosphere. We also discuss the computational difficulties inherent in these calculations.

Bercik, D. J.

2008-05-01

116

High resolution GLAS on the MCIDAS  

NASA Technical Reports Server (NTRS)

The GLAS physical inversion method for analysis of HIRS2/MSU data was implemented on the McIDAS. The method of analysis is identical to that used in processing global retrievals for six months of 1979, with the exception that the McIDAS retrievals are done on a higher spatial resolution, with one sounding attempted in every 4 x 4 array of HIRS2 spots, corresponding to roughly 80 x 80 km at nadir. This 4 x 4 array is further subdivided in 4 2 x 2 arrays with the sounding being performed utilizing all the spots in the single warmest 2 x 2 quadrant as sensed by the 11 micrometer window channel. Whether accurate retrievals can be performed on the high resolution grid without editing was determined. Different retrievals for a synoptic situation was compared and the guess dependence of the high resolution GLAS retrievals were examined. The orbit crossing the central United States at 1/21/79 09257 was studied. Radiosondes at 1200Z were used for comparison.

Susskind, J.; Atlas, R.; Pursch, A.

1984-01-01

117

Comparative Very-High-Resolution VUV Spectroscopy  

NASA Astrophysics Data System (ADS)

Despite their importance to the photochemistry of the terrestrial atmosphere, and many experimental studies, previous characterization of the Schumann-Runge (SR) bands of O2, B3 ? u- <- X3 ?_g^- (v, 0) (1750-2050 Å) has been limited by poor experimental resolution. In addition, our understanding of the SR spectrum is incomplete, many rovibrational transitions in the perturbed region of the spectrum [B(v > 15)] remaining unassigned. We review new very-high-resolution measurements of the O2 photoabsorption cross section in the SR bands. Tunable, narrow-bandwidth background vacuum-ultraviolet (VUV) radiation for the measurements ( 7 × 105 resolving power) was generated by the two-photon-resonant difference-frequency four-wave mixing in Xe of excimer-pumped dye-laser radiation. With the aid of these cross-section measurements, rovibrational and line-shape analyses have led to new insights into the molecular structure and predissociation dynamics of O2. The current VUV laser-spectroscopic measurements are shown to compare favourably with results from two other very-high-resolution experimental techniques, namely laser-induced fluorescence spectroscopy and VUV Fourier-transform spectroscopy, the latter performed using a synchrotron source.

Lewis, B. R.; Gibson, S. T.; Baldwin, K. G. H.; Dooley, P. M.; Waring, K.

118

MAMS - A high spatial resolution multispectral scanner  

NASA Technical Reports Server (NTRS)

The Multispectral Atmospheric Mapping Sensor (MAMS) is an airborne scanner which collects imagery in eight visible and three IR bands, with ground resolution of 100 m at a nominal aircraft altitude of 20 km. The visible channels provide continuous spectral coverage from 0.42 to 1.05 microns, and the IR channels measure upwelling and reflected radiation at combinations of 3.7, 6.5, 11.1, and 12.5 microns. These include channels nearly identical to the Landsat TM channels 1-4, and similar to those on the VISSR Atmospheric Sounder (VAS) and AVHRR instruments. The high spatial resolution permits investigation of surface thermal and atmospheric water vapor structure at scales not available from current stabilities. Significant modifications have been made since engineering flights in 1985 to improve the radiometric performance. The increased data quality and recent multidisciplinary applications of this data are presented.

Atkinson, Robert J.; Jedlovec, Gary J.

1989-01-01

119

Development of a high resolution PET  

SciTech Connect

A high resolution positron emission tomograph (PET) for brain studies has been developed, which consists of 5 detector rings (240 BGO's/ring). New multi-segment photomultiplier tubes (PMT) were adopted to the system with 5 mm wide BGO's. The system is designed to examine a patient sitting or lying down on a chair/bed couch. The functions of PMT auto gain control and real time image display are implemented in the system. The physical performance of the system was evaluated: the spatial resolution is 3.5 mm in the transaxial plane and 5.7 mm in the axial direction, and the total system sensitivity is 109 kcps/{mu}Ci/ml for a 20 cm dia. uniform phantom with a pulse height threshold of 350 keV.

Yamashita, T.; Uchida, H.; Okada, H.; Kurono, T.; Takemori, T.; Watanabe, M.; Shimizu, K.; Yoshikawa, E.; Ohmura, T.; Satoh, N.; Tanaka, E. (Hamamatsu Photonic K.K., 1126-1, Ichino-cho, Hamamatsu 435 (JP)); Nohara, N.; Tomitani, T.; Yamamoto, M.; Murayama, H.; Endo, M. (National Inst. of Radiological Sciences, Chiba (Japan))

1990-04-01

120

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

121

High resolution patterning of silica aerogels  

SciTech Connect

Three-dimensional metallic structures are fabricated with high spatial resolution in silica aerogels. In our method, silica hydrogels are prepared with a standard base-catalyzed route, and exchanged with an aqueous solution typically containing Ag{sup +} ions (1 M) and 2-propanol (0.2 M). The metal ions are reduced photolytically with a table-top ultraviolet lamp, or radiolytically, with a focused X-ray beam. We fabricated dots and lines as small as 30 x 70 {micro}m, protruding for several mm into the bulk of the materials. The hydrogels are eventually supercritically dried to yield aerogels, without any measurable change in the shape and spatial resolution of the lithographed structures. Transmission electron microscopy shows that illuminated regions are composed by Ag clusters with a size of several {micro}m, separated by thin layers of silica.

Bertino, M.F.; Hund, J.F.; Sosa, J.; Zhang, G.; Sotiriou-Leventis, C.; Leventis, N.; Tokuhiro, A.T.; Terry, J. (UMR-MUST); (IIT)

2008-10-30

122

The Universe at High Angular Resolution  

NASA Astrophysics Data System (ADS)

Sub-milliarsecond resolution in the UV-optical domain, combined with the unique spectral diagnostics available at these wavelengths, will be an invaluable resource for many areas of astrophysical research in the 21st century. Increasing the angular resolution to the sub-milliarsecond level will result in an advance of at least two orders of magnitude compared to that provided by HST and will lead to unprecedented opportunities for astrophysical studies of the observable Universe. Simultanous attainment of ultra high resolution and observation of faint objects is technically very difficult, and the inevitable compromises must be driven by the science goals. In this talk I will highlight the potential of these capabilities to address current observational challenges. Examples include direct imaging of inner disk regions and planet forming environments within several stellar radii of YSOs, and of the atmospheric structures in evolved stars; studies of origins of winds and outflows in large variety of sources ranging from stars to AGNs; exploring accretion processes in protostars and in a variety of interacting binaries; improvement of the cosmic distance scale, and others.

Karovska, M.

2004-05-01

123

High resolution thermal denaturation of mammalian DNAs.  

PubMed Central

High resolution melting profiles of different mammalian DNAs are presented. Melting curves of various mammalian DNAs were compared with respect to the degree of asymmetry, first moment, transition breath and Tmi of individual subtransitions. Quantitative comparison of the shape of all melting curves was made. Correlation between phylogenetical relations among mammals and shape of the melting profiles of their DNAs was demonstrated. The difference between multi-component heterogeneity of mammalian DNAs found by optical melting analysis and sedimentation in CsCl-netropsin density gradient is also discussed.

Guttmann, T; Vitek, A; Pivec, L

1977-01-01

124

High-resolution color photographic reproductions  

NASA Astrophysics Data System (ADS)

This paper will describe a fine-art reproduction process that: captures painting information with high-resolution color photographs; scans the information into a 300 megabyte digital file; performs a 3D color calibration in a dedicated hardware color-transform circuit; makes a master positive color transparency and makes a reproduction on polaroid color print film. The master transparency can be used to expose a large number of images. This combines the efficiency of instant photography with the color fidelity of digital color transforms.

McCann, John J.

1997-04-01

125

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.

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

2011-01-01

126

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

127

Future Groundbased High-Resolution IR Spectrometers  

NASA Astrophysics Data System (ADS)

After reviewing generally the current plans for high resolution infrared spectroscopy at large groundbased telescopes I will discuss in more detail the specific instruments under development for the ESO VLT on Paranal mountain in Chile. The first to be installed will be VISIR which will provide a variety of capabilities in the 8-28µm region including echelle spectroscopy at R ~ 30.000 in the 10µm atmospheric window. This will be followed by CRIRES a high resolution pre-dispersed echelle spectrograph designed to reach R ~ 100.000 over the wavelength range 1-5µm. A curvature sensing adaptive optics system feed is used to minimize slit losses and a 4096x512 pixel mosaic of Aladdin InSb array detectors is being developed to maximize the free spectral range covered in each order. Gas cells are being provided for the measurement of high precision radial velocities and a Fresnel rhomb plus Wollaston prism for magnetic Doppler imaging. Installation at the VLT is scheduled during the second half of 2004. I will review briefly some of the science goals of this instrument and discuss its expected capabilities and current development status.

Moorwood, Alan

2005-01-01

128

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

Microsoft Academic Search

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

Karel Deprez; Roel Van Holen; Stefaan Vandenberghe; Steven Staelens

2011-01-01

129

Daily High-Resolution-Blended Analyses for Sea Surface Temperature  

Microsoft Academic Search

Two new high-resolution sea surface temperature (SST) analysis products have been developed using optimum interpolation (OI). The analyses have a spatial grid resolution of 0.25° and a temporal resolution of 1 day. One product uses the Advanced Very High Resolution Radiometer (AVHRR) infrared satellite SST data. The other uses AVHRR and Advanced Microwave Scanning Radiometer (AMSR) on the NASA Earth

Richard W. Reynolds; Thomas M. Smith; Chunying Liu; Dudley B. Chelton; Kenneth S. Casey; Michael G. Schlax

2007-01-01

130

High-resolution Carbon/Carbon Multilayers  

NASA Astrophysics Data System (ADS)

To synthesize X-ray optical multilayers showing both high resolution and high reflectivity, spacer and absorber materials with low absorption coefficients for the desired spectral range are required. Beside the well-known candidates the material system Carbon / Carbon is interesting because of its low absorption coefficient over a wide spectral range and the opportunity, to deposit C-layers with different modifications, i.e. different optical properties. Simulations of C/C multilayers with different period thicknesses d and single layer densities ? show, that reflectivities R (Cu K? ) > 80% and a resolution ??~0.002° can be achieved for C/C layer stacks with d= 3 nm and N= 1000 periods. An advanced large area Pulsed Laser Deposition (LA-PLD) technology was used to deposit C/C multilayers on Si-substrates up to 4" diameter. The carbon film growth conditions for the spacer and absorber layers were optimised by the variation of selected laser parameters like pulse energy and ablation wavelength, to achieve a sufficient density contrast and smooth interfaces. C/C multilayers with period thickness d= 1.1...7.0 nm and more than 500 periods were deposited. The X-ray optical performance of the C/C multilayers was characterized by means of X-ray reflectometry. A reflectivity R > 50 % (CuK?) was measured for C/C multilayers with d= 17.2 nm and N= 106 periods. A peak resolution (??/?) ~ 1.1 % was obtained for a C/C multilayer structure with N= 80 periods and a period thickness d= 1.1nm. Results of TEM investigations indicate a regular morphology as well as smooth interfaces in the C-C layer stacks. Low compressive stresses were determined in C/C multilayers with different period thicknesses using X-ray diffraction techniques.

Baranov, Alexander M.; Dietsch, Reiner; Holz, Thomas; Menzel, Maik; Weissbach, Danny; Scholz, Roland; Melov, Valeri; Schreiber, Juergen

2002-12-01

131

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

132

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 µm 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 µm) 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.

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

2010-01-01

133

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

Pérez, Rubén; García, Ricardo; Schwarz, Udo

2009-07-01

134

High Resolution Spectroscopy of Uranus Near Equinox  

NASA Astrophysics Data System (ADS)

We obtained high resolution optical spectra of Uranus in December 2003, using the 2dcoude spectrograph of the McDonald Observatory 2.7 Harlan Smith Telescope. The spectrograph was configured in the high resolution mode giving a resolving power of 120,000. We obtained spectra of Uranus at the wavelengths of the H2 quadrupole (4-0) S(0) and S(1) lines as well as the CH4 6819 Angstrom feature. The observations were made near Uranus equinox, so on one of the nights we were able to spatially resolve two hemispheres along the spectrograph slit. The motivation behind the observations was to observe changes in the atmospheric structure as the northern hemisphere comes into view and responds to the increasing solar insolation. We present the results of atmospheric radiative transfer modeling to reproduce the observed H2 line profiles. We compare these results with the analyses of similar observations of the northern hemisphere made in 1980, one full Uranus season ago.

Bjerke, Lance; Baines, K. H.; Cochran, W. D.

2007-10-01

135

High resolution observations of Mercury's exosphere  

NASA Astrophysics Data System (ADS)

Before the arrival of Messenger at Mercury in 2008 the only source of information available on Mercury s environment is observations done from ground based observatories These observations provided a now large data set on Mercury s exosphere and in particular of its sodium component originally discovered by Potter et al Science 1985 Two other elements have been discovered in the same way the potassium Potter et al Icarus 1986 and the calcium Bida et al 2000 All this information helped us to much better understand the formation of Mercury s exosphere Moreover it helps to design of the payload of the forthcoming Bepi-Colombo mission High resolution spectroscopy has been obtained on night 29 and 30 october 2005 at the 3 6-m NTT telescope of ESO La Silla Chile using the EMMI instrument in its echelle spectroscopy mode Configuration of Mercury was favourable with an angular diameter of 6 arcseconds and the planet close to quadrature The disk of the planet has been scanned for spatial variation of the exospheric species The large spectral range of EMMI 3850-8550 A and high resolution R 75000 allow simultaneous measurements of the integrated column density of Na and K as well as search for non-identified species of Mercury s exosphere Data will be presented and discussed

Doressoundiram, A.; Leblanc, F.; Foellmi, C.

136

High Resolution BPM for Linear Colliders  

NASA Astrophysics Data System (ADS)

A high resolution Beam Position Monitor (BPM) is necessary for the beam-based alignment systems of high energy and low emittance electron linacs. Such a monitor is developed in the framework of the European CARE/SRF programme, in a close collaboration between DESY and CEA/DSM/DAPNIA. This monitor is a radiofrequency re-entrant cavity, which can be used either at room or cryogenic temperature, in an environment where dust particle contamination has to be avoided, such as superconducting cavities in a cryomodule. A first prototype of a re-entrant BPM has already delivered measurements at 2K. inside the first cryomodule (ACC1) on the TESLA Test Facility 2 (TTF2). The performances of this BPM are analyzed both experimentally and theoretically, and the limitations of this existing system clearly identified. A new cavity and new electronics have been designed in order to improve the position resolution down to 1 ?m and the damping time down to 10 ns.

Simon, C.; Chel, S.; Luong, M.; Napoly, O.; Novo, J.; Roudier, D.; Baboi, N.; Noelle, D.; Mildner, N.; Zapfe, K.; Rouvière, N.

2006-11-01

137

High Resolution Camera for Mapping Titan Surface  

NASA Technical Reports Server (NTRS)

Titan, Saturn's largest moon, has a dense atmosphere and is the only object besides Earth to have stable liquids at its surface. The Cassini/Huygens mission has revealed the extraordinary breadth of geological processes shaping its surface. Further study requires high resolution imaging of the surface, which is restrained by light absorption by methane and scattering from aerosols. The Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft has demonstrated that Titan's surface can be observed within several windows in the near infrared, allowing us to process several regions in order to create a geological map and to determine the morphology. Specular reflections monitored on the lakes of the North Pole show little scattering at 5 microns, which, combined with the present study of Titan's northern pole area, refutes the paradigm that only radar can achieve high resolution mapping of the surface. The present data allowed us to monitor the evolution of lakes, to identify additional lakes at the Northern Pole, to examine Titan's hypothesis of non-synchronous rotation and to analyze the albedo of the North Pole surface. Future missions to Titan could carry a camera with 5 micron detectors and a carbon fiber radiator for weight reduction.

Reinhardt, Bianca

2011-01-01

138

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

139

Limiting liability via high resolution image processing  

SciTech Connect

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

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

1996-12-31

140

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

141

High-Resolution Radar Imagery of Mars  

NASA Astrophysics Data System (ADS)

We present high-resolution radar images of Mars obtained during the 2005 and 2007 oppositions. The images were constructed from long-code delay-Doppler observations made with the Arecibo S-band (13-cm) radar. The average image resolution of 3 km represented a better than order-of-magnitude improvement over pre-upgrade Arecibo imagery of the planet. Images of depolarized reflectivity (an indicator primarily of wavelength-scale surface roughness) show the same bright volcanic flow features seen in earlier imagery, but with much finer detail. A new image of the Elysium region shows fine detail in the radar-bright channels of Athabasca Vallis, Marte Vallis, and Grjota Vallis. The new images of Tharsis and Olympus Mons also show a complex array of radar-bright and radar-dark features. Southern Amazonis exhibits some of the most complex and puzzling radar-bright structure on the planet. Another curiosity is the Chryse/Xanthe/Channels region, where we find some radar-bright features in or adjacent to fluvial chaos structures. Chryse/Xanthe is also the only region of Mars showing radar-bright craters (which are rare on Mars but common on the Moon and Mercury). We also obtained the first delay-Doppler image showing the enhanced backscatter from the residual south polar ice cap. In addition to the depolarized imagery, we were able to make the first delay-Doppler images of the circular polarization ratio (an important diagnostic for surface roughness texture). We find that vast areas of the radar-bright volcanic regions have polarization ratios close to unity. Such high ratios are rare for terrestrial lava flows and only seen for extremely blocky surfaces giving high levels of multiple scattering.

Harmon, John K.; Nolan, M. C.

2009-09-01

142

High Resolution Radar Measurements of Snow Avalanches  

NASA Astrophysics Data System (ADS)

Geophysical mass flows, such as snow avalanches, are a major hazard in mountainous areas and have a significant impact on the infrastructure, economy and tourism of such regions. Obtaining a thorough understanding of the dynamics of snow avalanches is crucial for risk assessment and the design of defensive structures. However, because the underlying physics is poorly understood there are significant uncertainties concerning current models, which are poorly validated due to a lack of high resolution data. Direct observations of the denser core of a large avalanche are particularly difficult, since it is frequently obscured by the dilute powder cloud. We have developed and installed a phased array FMCW radar system that penetrates the powder cloud and directly images the dense core with a resolution of around 1 m at 50 Hz over the entire slope. We present data from recent avalanches at Vallée de la Sionne that show a wealth of internal structure and allow the tracking of individual fronts, roll waves and surges down the slope for the first time. We also show good agreement between the radar results and existing measurement systems that record data at particular points on the avalanche track.

McElwaine, J. N.; Vriend, N. M.; Sovilla, B.; Keylock, C. J.; Brennan, P.; Ash, M.

2012-12-01

143

High Resolution Radar Measurements of Snow Avalanches  

NASA Astrophysics Data System (ADS)

Geophysical mass flows, such as snow avalanches, are a major hazard in mountainous areas and have a significant impact on the infrastructure, economy and tourism of such regions. Obtaining a thorough understanding of the dynamics of snow avalanches is crucial for risk assessment and the design of defensive structures. However, because the underlying physics is poorly understood there are significant uncertainties concerning current models, which are poorly validated due to a lack of high resolution data. Direct observations of the denser core of a large avalanche are particularly difficult, since it is frequently obscured by the dilute powder cloud. We have developed and installed a phased array FMCW radar system that penetrates the powder cloud and directly images the dense core with a resolution of around 1 m at 50 Hz over the entire slope. We present data from recent avalanches at Vallee de la Sionne that show a wealth of internal structure and allow the tracking of individual fronts, roll waves and surges down the slope for the first time. We also show good agreement between the radar results and existing measurement systems that record data at particular points on the avalanche track.

McElwaine, Jim; Sovilla, Betty; Vriend, Nathalie; Brennan, Paul; Ash, Matt; Keylock, Chris

2013-04-01

144

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

145

High resolutions spectroscopy of P/Halley  

NASA Technical Reports Server (NTRS)

High resolution spectra of the coma of P/Halley were obtained on 25 April, 2 May, and 3 May 1986. The self-scanned Digicon detector of the 2.7 m telescope coude spectrograph was used to obtain spectra at a resolution of 0.6A. Results of the observation of the NH (A 3 Pi i yields X 3 Sigma (-)) band near 3360 A are presented. The summed NH spectrum represents the results of 190 min of integration centered on the nucleus of the comet. Eight rotational lines from the P and R branches of the band are detected. The lines from the Q branch are especially weak, and are not obviously resolved in the spectrum. The data are compared with the theoretical emission spectrum of Litvak and Kuiper (1982) and substantial discrepancies are found. These discrepancies are explained through a consideration of the relative timescales for collisions, resonance fluorescence, and radiative decays of the NH molecules in the coma.

Cochran, W. D.

1986-01-01

146

High resolutions spectroscopy of P/Halley  

NASA Astrophysics Data System (ADS)

High resolution spectra of the coma of P/Halley were obtained on 25 April, 2 May, and 3 May 1986. The self-scanned Digicon detector of the 2.7 m telescope coude spectrograph was used to obtain spectra at a resolution of 0.6A. Results of the observation of the NH (A 3 Pi i yields X 3 Sigma (-)) band near 3360 A are presented. The summed NH spectrum represents the results of 190 min of integration centered on the nucleus of the comet. Eight rotational lines from the P and R branches of the band are detected. The lines from the Q branch are especially weak, and are not obviously resolved in the spectrum. The data are compared with the theoretical emission spectrum of Litvak and Kuiper (1982) and substantial discrepancies are found. These discrepancies are explained through a consideration of the relative timescales for collisions, resonance fluorescence, and radiative decays of the NH molecules in the coma.

Cochran, W. D.

1986-12-01

147

A high-resolution microchip optomechanical accelerometer  

NASA Astrophysics Data System (ADS)

The monitoring of acceleration is essential for a variety of applications ranging from inertial navigation to consumer electronics. Typical accelerometer operation involves the sensitive displacement measurement of a flexibly mounted test mass, which can be realized using capacitive, piezo-electric, tunnel-current or optical methods. Although optical detection provides superior displacement resolution, resilience to electromagnetic interference and long-range readout, current optical accelerometers either do not allow for chip-scale integration or utilize relatively bulky test mass sensors of low bandwidth. Here, we demonstrate an optomechanical accelerometer that makes use of ultrasensitive displacement readout using a photonic-crystal nanocavity monolithically integrated with a nanotethered test mass of high mechanical Q-factor. This device achieves an acceleration resolution of 10 µg Hz-1/2 with submilliwatt optical power, bandwidth greater than 20 kHz and a dynamic range of greater than 40 dB. Moreover, the nanogram test masses used here allow for strong optomechanical backaction, setting the stage for a new class of motional sensors.

Krause, Alexander G.; Winger, Martin; Blasius, Tim D.; Lin, Qiang; Painter, Oskar

2012-11-01

148

Clementine High Resolution Camera Mosaicking Project  

NASA Astrophysics Data System (ADS)

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.

1998-10-01

149

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

150

Resolution and Contrast in the Conventional and the Scanning High Resolution Transmission Electron Microscopes.  

National Technical Information Service (NTIS)

The Conventional Electron Microscope (CEM) and the high resolution Scanning Transmission Electron Microscope (STEM) are analysed and compared using a simplified theoretical model and a geometrical optical treatment. The contrast and resolution are numeric...

M. G. R. Thomson

1973-01-01

151

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

152

HYPOLIT, a high resolution fast beam RICH  

NASA Astrophysics Data System (ADS)

A new Cherenkov counter has been designed for on-line tagging of high energy particles, more specifically 270 GeV hyperons in WA89 experiment at CERN. It is equipped with a 6 m focal length spherical mirror and a chromatic corrector. The ring size is reduced by a factor of 8 (adjustable) by means of a set of two conical mirrors. The photon detector is an image intensifier. Its output window is divided in 160 pixels read with photomultipliers via optical fibres. The ring radius is determined electronically and a tagging signal is available in less than 2.5 ?s. HYPOLIT has been tested in a 220 GeV pion beam (50 ?rad divergence). A spatial resolution of 0.125 mm on the radius has been obtained, and the pion—kaon separation was better than 5?.

Ballon, J.; Bérat, C.; Buénerd, M.; Chauvin, J.; Hostachy, J. Y.; Laâmyem, M.; Martin, Ph.; Sghaier, H.; Stassi, P.; Rey-Campagnolle, M.; Touillon, R.; Volkemer, B.

1994-04-01

153

High resolution rocket EUV solar spectrograph.  

NASA Technical Reports Server (NTRS)

The design and performance of an Aerobee 150 rocket-borne solar spectrograph covering a wavelength range of 10 to 385 A are discussed. The spectrograph uses a gold-coated replica concave grating of 3-m radius with 1200 grooves/mm at an angle of incidence of 88 deg. The spectra are recorded on glass photographic plates making possible wavelength determination to 0.003 A if known standard wavelengths occur frequently enough. Special attention to scattered light made possible the photographing of the solar spectrum from 60 to 385 A without using filters to absorb the strong visible and UV sunlight, although the solar spectrum was also recorded through metal foil filters. In the laboratory the spectrograph has been used to record spectra of highly ionized metals with a resolution of 0.03 A or better.

Behring, W. E.; Ugiansky, R. J.; Feldman, U.

1973-01-01

154

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

155

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 1×1 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.

Bräuer-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

156

A new high-resolution TOF technology  

NASA Astrophysics Data System (ADS)

In the framework of the ALICE collaboration we have recently studied the performance of multigap Resistive Plate Chambers operated in avalanche mode and at atmospheric pressure for time-of-flight measurements. The detector provided an overall (detector plus electronics) timing accuracy of 120 ps sigma at an efficiency of 98% for MIPs. The chambers had four gas gaps of 0.3 mm, each limited by a metallised ceramic plate and a glass plate, with an active dimension of 4×4cm 2. The gas mixture contained C 2H 2F 4+5% isobutane+10% SF 6. A few percent of streamer discharges, each releasing about 20 pC, was tolerated without any noticeable inconvenience. This detector opens perspectives of affordable and reliable high granularity large area TOF detectors, with an efficiency and a time resolution comparable to existing scintillator-based TOF technology but with significantly, up to an order of magnitude, lower price per channel.

Fonte, P.; Smirnitski, A.; Williams, M. C. S.

2000-03-01

157

High-Resolution Transcriptome of Human Macrophages  

PubMed Central

Macrophages are dynamic cells integrating signals from their microenvironment to develop specific functional responses. Although, microarray-based transcriptional profiling has established transcriptional reprogramming as an important mechanism for signal integration and cell function of macrophages, current knowledge on transcriptional regulation of human macrophages is far from complete. To discover novel marker genes, an area of great need particularly in human macrophage biology but also to generate a much more thorough transcriptome of human M1- and M1-like macrophages, we performed RNA sequencing (RNA-seq) of human macrophages. Using this approach we can now provide a high-resolution transcriptome profile of human macrophages under classical (M1-like) and alternative (M2-like) polarization conditions and demonstrate a dynamic range exceeding observations obtained by previous technologies, resulting in a more comprehensive understanding of the transcriptome of human macrophages. Using this approach, we identify important gene clusters so far not appreciated by standard microarray techniques. In addition, we were able to detect differential promoter usage, alternative transcription start sites, and different coding sequences for 57 gene loci in human macrophages. Moreover, this approach led to the identification of novel M1-associated (CD120b, TLR2, SLAMF7) as well as M2-associated (CD1a, CD1b, CD93, CD226) cell surface markers. Taken together, these data support that high-resolution transcriptome profiling of human macrophages by RNA-seq leads to a better understanding of macrophage function and will form the basis for a better characterization of macrophages in human health and disease.

Xue, Jia; Staratschek-Jox, Andrea; Vorholt, Daniela; Krebs, Wolfgang; Sommer, Daniel; Sander, Jil; Mertens, Christina; Nino-Castro, Andrea; Schmidt, Susanne V.; Schultze, Joachim L.

2012-01-01

158

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 H2O (water vapor), O3 (ozone), HCN (hydrogen cyanide), CH4 (methane), NO2 (nitrogen dioxide) and CO (carbon monoxide). The data required for the analyses were obtained from two different Fourier Transform Spectrometers (FTS); one of which is located at the National Solar Observatory (NSO) on Kitt Peak, Arizona and the other instrument is located at the Pacific Northwest National Laboratories (PNNL) at Richland, Washington. The data were analyzed using a modified multispectrum nonlinear least squares fitting algorithm developed by Dr. D. Chris Benner of the College of William and Mary. The results from these studies made significant improvements in the line positons and intensities for these molecules. The measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced shift coefficients for hundreds of infrared transitions of HCN, CO3 CH4 and H2O were also performed during this period. 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. The research conducted during the period 2003-2006 has resulted in publications given in this paper. In addition to Journal publications, several oral and poster presentations were given at various Scientific conferences within the United States and abroad.

Venkataraman, Malathy Devi

2006-01-01

159

IMAGE PROCESSING FOR HIGH RESOLUTION SATELLITE AND AERIAL DATA  

Microsoft Academic Search

The last few years have seen the launch of several high- resolution satellites, and many more are planned in the near future. In parallel, new high-resolution CCD cameras for use in aerial photography have been developed. In this paper, we focus on this new optical high-resolution data. We present the challenges arising from the new technology in the introduction, and

Josiane Zerubia

160

Clementine High Resolution Camera Mosaicking Project  

NASA Astrophysics Data System (ADS)

This compact disk (CD) is part of the Clementine I high resolution (HiRes) camera lunar image mosaics developed by Malin Space Science Systems (MSSS). These mosaics were developed through calibration and semi-automated registration against the recently released geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic, which is available through the PDS, as CD-ROM volumes CL_3001-3015. The HiRes mosaics are compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution observations from the HiRes imaging system onboard the Clementine Spacecraft. The geometric control is provided by the U. S. Geological Survey (USGS) Clementine Basemap Mosaic compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Calibration was achieved by removing the image nonuniformity largely caused 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 mosaics on this CD are compiled from polar data (latitudes greater than 80 degrees), and are presented in the stereographic projection at a scale of 30 m/pixel at the pole, a resolution 5 times greater than that (150 m/pixel) of the corresponding UV/Vis polar basemap. This 5:1 scale ratio is in keeping with the sub-polar mosaic, in which the HiRes and UV/Vis mosaics had scales of 20 m/pixel and 100 m/pixel, respectively. The equal-area property of the stereographic projection made this preferable for the HiRes polar mosaic rather than the basemap's orthographic projection. Thus, a necessary first step in constructing the mosaic was the reprojection of the UV/Vis basemap to the stereographic projection. The HiRes polar data can be naturally grouped according to the orbital periapsis, which was in the south during the first half of the mapping mission and in the north during the second half. Images in each group have generally uniform intrinsic resolution, illumination, exposure and gain. Rather than mingle data from the two periapsis epochs, separate mosaics are provided for each, a total of 4 polar mosaics. The mosaics are divided into 100 square tiles of 2250 pixels (approximately 2.2 deg near the pole) on a side. Not all squares of this grid contain HiRes mosaic data, some inevitably since a square is not a perfect representation of a (latitude) circle, others due to the lack of HiRes data. This CD also contains 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. For more information on the contents and organization of the CD volume set refer to the "FILES, DIRECTORIES AND DISK CONTENTS" section of this document. The image files are organized according to NASA's Planetary Data System (PDS) standards. An image file (tile) is organized as a PDS labeled file containing an "image object".

Malin, Michael; Revine, Michael

1998-10-01

161

Clementine High Resolution Camera Mosaicking Project  

NASA Astrophysics Data System (ADS)

This compact disk (CD) is part of the Clementine I high resolution (HiRes) camera lunar image mosaics developed by Malin Space Science Systems (MSSS). These mosaics were developed through calibration and semi-automated registration against the recently released geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic, which is available through the PDS, as CD-ROM volumes CL_3001-3015. The HiRes mosaics are compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution observations from the HiRes imaging system onboard the Clementine Spacecraft. The geometric control is provided by the U.S. Geological Survey (USGS) Clementine Basemap Mosaic compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Calibration was achieved by removing the image nonuniformity largely caused 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 mosaics on this CD are compiled from polar data (latitudes greater than 80 degrees), and are presented in the stereographic projection at a scale of 30 m/pixel at the pole, a resolution 5 times greater than that (150 m/pixel) of the corresponding UV/Vis polar basemap. This 5:1 scale ratio is in keeping with the sub-polar mosaic, in which the HiRes and UV/Vis mosaics had scales of 20 m/pixel and 100 m/pixel, respectively. The equal-area property of the stereographic projection made this preferable for the HiRes polar mosaic rather than the basemap's orthographic projection. Thus, a necessary first step in constructing the mosaic was the reprojection of the UV/Vis basemap to the stereographic projection. The HiRes polar data can be naturally grouped according to the orbital periapsis, which was in the south during the first half of the mapping mission and in the north during the second half. Images in each group have generally uniform intrinsic resolution, illumination, exposure and gain. Rather than mingle data from the two periapsis epochs, separate mosaics are provided for each, a total of 4 polar mosaics. The mosaics are divided into 100 square tiles of 2250 pixels (approximately 2.2 deg near the pole) on a side. Not all squares of this grid contain HiRes mosaic data, some inevitably since a square is not a perfect representation of a (latitude) circle, others due to the lack of HiRes data. This CD also contains 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. For more information on the contents and organization of the CD volume set refer to the "FILES, DIRECTORIES AND DISK CONTENTS" section of this document. The image files are organized according to NASA's Planetary Data System (PDS) standards. An image file (tile) is organized as a PDS labeled file containing an "image object".

Malin, Michael; Revine, Michael

1998-10-01

162

Toward high-resolution optoelectronic retinal prosthesis  

NASA Astrophysics Data System (ADS)

It has been already demonstrated that electrical stimulation of retina can produce visual percepts in blind patients suffering from macular degeneration and retinitis pigmentosa. Current retinal implants provide very low resolution (just a few electrodes), while several thousand pixels are required for functional restoration of sight. We present a design of the optoelectronic retinal prosthetic system that can activate a retinal stimulating array with pixel density up to 2,500 pix/mm2 (geometrically corresponding to a visual acuity of 20/80), and allows for natural eye scanning rather than scanning with a head-mounted camera. The system operates similarly to "virtual reality" imaging devices used in military and medical applications. An image from a video camera is projected by a goggle-mounted infrared LED-LCD display onto the retina, activating an array of powered photodiodes in the retinal implant. Such a system provides a broad field of vision by allowing for natural eye scanning. The goggles are transparent to visible light, thus allowing for simultaneous utilization of remaining natural vision along with prosthetic stimulation. Optical control of the implant allows for simple adjustment of image processing algorithms and for learning. A major prerequisite for high resolution stimulation is the proximity of neural cells to the stimulation sites. This can be achieved with sub-retinal implants constructed in a manner that directs migration of retinal cells to target areas. Two basic implant geometries are described: perforated membranes and protruding electrode arrays. Possibility of the tactile neural stimulation is also examined.

Palanker, Daniel; Huie, Philip; Vankov, Alexander; Asher, Alon; Baccus, Steven

2005-04-01

163

High resolution studies of circumstellar masers  

NASA Astrophysics Data System (ADS)

This thesis describes in detail the observational procedures that we have followed and developed to analyze several research projects organized at Onsala since 1990 to study the regions of SiO maser emission at 43 GHz in the circumstellar envelopes of late-type stars with very high angular resolution. The compact nature of these SiO maser regions has been demonstrated in this work. In fact, we find that they are an order of magnitude smaller than previously reported. As a consequence, they can be studied with the available VLBI instruments. We have used the EVN and VLBA telescopes to produce images of the distribution of the SiO maser features in several sources, in particular R Cassiopeiae and VX Sagittarii. Through this work, we discuss in detail the procedures involved in all the project steps, from the scheduling of the observations to the calibration, imaging, and modelling of the source structure. We compare our results with those of other instruments at different frequencies for the same objects. This thesis also describes the analysis of observations of water masers at 22 GHz in several late-type stars using the VLA. The limited resolution of these observations made us develop a computer program, "FG3", that would search for the maser sources (blended spatially and in frequency) and extract them via 3D least squares fitting to Gaussian functions. This is, to our knowledge, a new approach in this kind of investigations. This program provides information of not only the source structure distribution and kinematics, but also measures parameters that are directly related with the physical conditions in the masing regions. In particular, we conclude by the study of the fitted maser linewidths that water masers in late-type stars are unsaturated, and experiment exponential growth. We are not able to reach a clear conclusion for the SiO masers in the supergiant star VX Sgr, but there are indications that they might be saturated.

Colomer, F.

1996-06-01

164

GaAs pixel radiation detector as an autoradiography tool for genetic studies  

NASA Astrophysics Data System (ADS)

We present an autoradiography tool to be used mainly for genetic studies. It performs a quantitative analysis of radioactivity and can follow a dynamic process. We designed several applications, in particular one aimed at detecting hybridization of radio-labeled DNA fragments with known DNA-probes deposited on a micro-array. The technique is based on GaAs pixel array detector and low threshold, large dynamic range and good sensitivity integrated electronics developed for medical applications, suitable to detect markers (gamma or beta) such as 14C, 35S, 33P, 32P, 125I, even at very low activities. A Monte Carlo simulation of ?- detection in GaAs is presented here in order to study the spatial resolution characteristics of such a system. For several biological applications, the electronics is required to perform at high temperatures (from 37° to 68°): we present here studies of noise and minimum threshold as a function of the temperature.

Bertolucci, E.; Conti, M.; Mettivier, G.; Russo, P.; Amendolia, S. R.; Bisogni, M. G.; Bottigli, U.; Ceccopieri, A.; Ciocci, M. A.; Delogu, P.; Fantacci, M. E.; Maestro, P.; Marzulli, V. M.; Pernigotti, E.; Romeo, N.; Rosso, V.; Stefanini, A.; Stumbo, S.

1999-02-01

165

Clementine High Resolution Camera Mosaicking Project  

NASA Astrophysics Data System (ADS)

This compact disk (CD) is part of the Malin Space Science Systems (MSSS) effort to mosaic Clementine I high resolution (HiRes) camera lunar images. These mosaics were developed through calibration and semi-automated registration against the recently released geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic, which is available through the PDS, as CD-ROM volumes CL_3001-3015. The HiRes mosaics are compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution observations from the HiRes imaging system onboard the Clementine Spacecraft. These mosaics are spatially warped using the sinusoidal equal-area projection at a scale of 20 m/pixel. The geometric control is provided by the 100 m/pixel U.S. Geological Survey (USGS) Clementine Basemap Mosaic compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Calibration was achieved by removing the image nonuniformity largely caused 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 mosaics on this CD were compiled from sub-polar data (latitudes 80 degrees South to 80 degrees North; -80 to +80) within the longitude range 0-30 deg E. The mosaics are divided into tiles that cover approximately 1.75 degrees 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. This CD contains 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. For more information on the contents and organization of the CD volume set refer to the "FILES, DIRECTORIES AND DISK CONTENTS" section of this document. The image files are organized according to NASA's Planetary Data System (PDS) standards. An image file (tile) is organized as a PDS labeled file containing an "image object".

Malin, Michael; Revine, Michael

1998-10-01

166

Clementine High Resolution Camera Mosaicking Project  

NASA Astrophysics Data System (ADS)

This compact disk (CD) is part of the Malin Space Science Systems (MSSS) effort to mosaic Clementine I high resolution (HiRes) camera lunar images. These mosaics were developed through calibration and semi-automated registration against the recently released geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic, which is available through the PDS, as CD-ROM volumes CL_3001-3015. The HiRes mosaics are compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution observations from the HiRes imaging system onboard the Clementine Spacecraft. These mosaics are spatially warped using the sinusoidal equal-area projection at a scale of 20 m/pixel. The geometric control is provided by the 100 m/pixel U. S. Geological Survey (USGS) Clementine Basemap Mosaic compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Calibration was achieved by removing the image nonuniformity largely caused 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 mosaics on this CD were compiled from sub-polar data (latitudes 80 degrees South to 80 degrees North; -80 to +80) within the longitude range 0-30 deg E. The mosaics are divided into tiles that cover approximately 1.75 degrees 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. This CD contains 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. For more information on the contents and organization of the CD volume set refer to the "FILES, DIRECTORIES AND DISK CONTENTS" section of this document. The image files are organized according to NASA's Planetary Data System (PDS) standards. An image file (tile) is organized as a PDS labeled file containing an "image object".

Malin, Michael; Revine, Michael

1998-10-01

167

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

168

Precision rectification of high resolution satellite imagery without ephemeris data  

Microsoft Academic Search

The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetry, Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling. The satellite orbit, position, attitude angles and interior orientation parameters have

Saeid Sadeghian; Mohammad Javad Valadan Zoej; Mahmoud Reza Delavar; Ahmad Abootalebi

2001-01-01

169

High Resolution Modeling of the Gulf of Mexico.  

National Technical Information Service (NTIS)

An advanced, high-resolution numerical ocean model is employed to investigate the dynamics and physical characteristics of the deep and shallow circulation in the Gulf of Mexico. The resolution of the ocean model (approx. 4 kilometers) and revolutionary h...

P. J. Hogan

2005-01-01

170

A New Source of High Resolution Lunar Images: Amateur Astronomers!  

NASA Astrophysics Data System (ADS)

A new source of relatively high-resolution lunar images exists. Amateur astronomers using 8" to 14" telescopes, webcams and stacking software, produce images with resolutions of 300 500 m. Near-terminator images can show unknown small features.

Wood, C. A.; Pau, K. C.; Daversin, B.

2004-03-01

171

High frequency photoacoustic microscopy for high resolution imaging  

Microsoft Academic Search

\\u000a Photoacoustic imaging (also called optoacoustic imaging) is a new hybrid imaging modality which offers tremendous potential\\u000a for research and clinical applications and features main advantages of optical and acoustical techniques. It combines ultrasonic\\u000a resolution with high optical contrast since signal generation is due to light absorption depending on the physiology of the\\u000a examined biological tissue. The acoustic signal reports tissue-specific

W. Bost; F. Stracke; Y. Kohl; M. Fournelle; R. Lemor

172

Design techniques for high-speed, high-resolution comparators  

Microsoft Academic Search

Precision techniques for the design of comparators used in high-performance analog-to-digital converters employing parallel conversion stages are described. Following a review of conventional offset cancellation techniques, circuit designs achieving 12-b resolution in both BiCMOS and CMOS 5-V technologies are presented. The BiCMOS comparator consists of a preamplifier followed by two regenerative stages and achieves an offset of 200 ?V at

Behzad Razavi; Bruce A. Wooley

1992-01-01

173

High spatial resolution probes for neurobiology applications  

NASA Astrophysics Data System (ADS)

Position-sensitive biological neural networks, such as the brain and the retina, require position-sensitive detection methods to identify, map and study their behavior. Traditionally, planar microelectrodes have been employed to record the cell's electrical activity with device limitations arising from the electrode's 2-D nature. Described here is the development and characterization of an array of electrically conductive micro-needles aimed at addressing the limitations of planar electrodes. The capability of this array to penetrate neural tissue improves the electrode-cell electrical interface and allows more complicated 3-D networks of neurons, such as those found in brain slices, to be studied. State-of-the-art semiconductor fabrication techniques were used to etch and passivate conformally the metal coat and fill high aspect ratio holes in silicon. These are subsequently transformed into needles with conductive tips. This process has enabled the fabrication of arrays of unprecedented dimensions: 61 hexagonally close-packed electrodes, ˜200 ?m tall with 60 ?m spacing. Electroplating the tungsten tips with platinum ensure suitable impedance values (˜600 k? at 1 kHz) for the recording of neuronal signals. Without compromising spatial resolution of the neuronal recordings, this array adds a new and exciting dimension to the study of biological neural networks.

Gunning, D. E.; Kenney, C. J.; Litke, A. M.; Mathieson, K.

2009-06-01

174

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

175

Europa Ice Cliffs-High Resolution  

NASA Technical Reports Server (NTRS)

This view of the Conamara Chaos region on Jupiter's moon Europa shows cliffs along the edges of high-standing ice plates. The washboard texture of the older terrain has been broken into plates which are separated by material with a jumbled texture. The cliffs themselves are rough and broadly scalloped, and smooth debris shed from the cliff faces is piled along the base. For scale, the height of the cliffs and size of the scalloped indentations are comparable to the famous cliff face of Mount Rushmore in South Dakota.

This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by the solid state imaging system (camera) on NASA's Galileo spacecraft. North is to the top right of the picture, and the sun illuminates the surface from the east. This image, centered at approximately 8 degrees north latitude and 273 degrees west longitude, covers an area approximately 1.5 kilometers by 4 kilometers (0.9 miles by 2.4 miles). The resolution is 9 meters (30 feet) per picture element.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

1998-01-01

176

High resolution observations of the Evershed flow  

NASA Astrophysics Data System (ADS)

Observations with high spatial resolution of the Evershed effect in a sunspot near the limb are presented. They were obtained with the Gregory Coude Telescope at Observatorio del Teide, Tenerife, and consist of photographic spectrograms in the wavelength region 5160-5180A and corresponding slit-jaw images in white light at various positions of the sunspot image on the slit of the spectrograph. The measurement of the velocity field covers a height range of approximately 100 km to 700 km in the Mg b2 line. The Evershed flow is inhomogeneous at all heights, though decreasing in amplitude with increasing height. We find maximum velocities of 4 km/s at the lowest layer. The flow goes clearly beyond the outer penumbra border. In Mg b2 the Evershed effect is inverse, on average, while at the 500 km level it is not. We suggest that in one fortunate case, with slit orientation parallel to a flow tube, we see siphon flows outward, reaching to the height of the Mg b2 layer and ending in photospheric faculae. The stationarity of the flow on small scales is questioned.

Boerner, P.; Kneer, F.

1992-06-01

177

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

178

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

179

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

180

High Resolution Spectra of Solar Flares  

NASA Astrophysics Data System (ADS)

I discuss high-resolution solar flare spectra from the soft X-ray region through the extreme ultraviolet (EUV) wavelength regions. Spectra of solar flares at these wavelengths have been recorded since the late 1960s, beginning primarily with the NASA Orbiting Solar Observatory (OSO) series of spacecraft. Knowledge of EUV flare spectra took a quantum leap with the NASA Skylab Apollo Telescope Mount spectrographs in the early 1970s. Knowledge of the X-ray spectrum took a similar leap in the 1980s with the US Department of Defense P78-1 spacecraft, the NASA Solar Maximum Mission spacecraft (SMM), and the Japanese Hinotori spacecraft. Investigations of flare X-ray spectra continued with the BCS X-ray spectrometer experiment on the Japanese Yohkoh mission. Recently, EUV solar flare spectroscopy has been extended with the SUMER spectrometer on the ESA SOHO spacecraft. In addition to the above missions, significant contributions were made with instrumentation on a number of other spacecraft, e.g., the Soviet Intercosmos X-ray spectrometers. Our knowledge of the physical conditions in solar flares has been greatly expanded from analyses of X-ray and EUV flare spectra. I will discuss the general characteristics of the flare emission line and continuum spectra, and the physical processes that produce them. I will discuss what we have learned about solar flares from the spectra, and discuss solar flare spectra in terms of spectra expected from other astrophysical sources.

Doschek, G. A.

181

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.

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

2014-01-01

182

High-resolution microwave images of saturn.  

PubMed

An analysis of high-resolution microwave images of Saturn and Saturn's individual rings is presented. Radio interferometric observations of Saturn taken at the Very Large Array in New Mexico at wavelengths of 2 and 6 centimeters reveal interesting new features in both the atmosphere and rings. The resulting maps show an increase in brightness temperature of about 3 K from equator to pole at both wavelengths, while the 6-centimeter map shows a bright band at northern mid-latitudes. The data are consistent with a radiative transfer model of the atmosphere that constrains the well-mixed, fully saturated, NH(3) mixing ratio to be 1.2 x 10(-4) in a region just below the NH(3) clouds, while the observed bright band indicates a 25 percent relative decrease of NH(3) in northern mid-latitudes. Brightness temperatures for the classical rings are presented. Ring brightness shows a variation with azimuth and is linearly polarized at an average value of about 5 percent. The variations in ring polarization suggest that at least 20 percent of the ring brightness is the result of a single scattering process. PMID:17747882

Grossman, A W; Muhleman, D O; Berge, G L

1989-09-15

183

High resolution gas volume change sensor  

SciTech Connect

Changes of gas quantity in a system can be measured either by measuring pressure changes or by measuring volume changes. As sensitive pressure sensors are readily available, pressure change is the commonly used technique. In many physiologic systems, however, buildup of pressure influences the gas exchange mechanisms, thus changing the gas quantity change rate. If one wants to study the gas flow in or out of a biological gas pocket, measurements need to be done at constant pressure. In this article we present a highly sensitive sensor for quantitative measurements of gas volume change at constant pressure. The sensor is based on optical detection of the movement of a droplet of fluid enclosed in a capillary. The device is easy to use and delivers gas volume data at a rate of more than 15 measurements/s and a resolution better than 0.06 {mu}l. At the onset of a gas quantity change the sensor shows a small pressure artifact of less than 15 Pa, and at constant change rates the pressure artifact is smaller than 10 Pa or 0.01% of ambient pressure.

Dirckx, Joris J. J.; Aernouts, Jef E. F.; Aerts, Johan R. M. [Laboratory of Biomedical Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp, Flanders B-2020 (Belgium)

2007-05-15

184

Investigation into High Spectral Resolution Lidar technologies  

NASA Astrophysics Data System (ADS)

The Intergovernmental Panel on Climate Change (IPCC) found in their 2007 report that aerosol radiative forcing contributed larger uncertainties to estimates affecting future climate change than any other radiative forcing factor. Lidar is a tool with which this uncertainty can be reduced, increasing our understanding of the impact of aerosols on climate change. Lidar, or laser radar, is a monostatic active remote sensing technique used to measure aerosols and particulates in the atmosphere, with accuracies comparable to in-situ measurements (Russell 2002). High Spectral Resolution Lidar (HSRL) systems use a narrow band filter to spectrally separate Doppler broadened aerosol and molecular back-scattered return signals, which allows for range resolved profiles of aerosol extinction and backscatter. The narrow band filter is a key component, for which two novel approaches are currently being used: NASA Langley Research Center has implemented a wide-angle Michelson interferometer in the second version of their airborne HSRL, and Montana State University is using a spherical Fabry-Perot interferometer in a ground based HSRL. In this research, a comprehensive comparative analysis of these two interferometric filters is performed, the result of which is a methodology for the design of narrow band filters for HSRL systems. The techniques presented identify the critical components and analyze the performance of each filter based on the spectral and angular properties, as well as the efficiency.

Dawsey, Martha Wallis

185

High-resolution hyperspectral imaging via matrix factorization  

Microsoft Academic Search

Hyperspectral imaging is a promising tool for applications in geosensing, cultural heritage and beyond. However, compared to current RGB cameras, existing hyperspectral cameras are severely limited in spatial resolution. In this paper, we introduce a simple new technique for reconstructing a very high-resolution hyperspectral image from two readily obtained measurements: A lower-resolution hyperspectral image and a high-resolution RGB image. Our

Rei Kawakami; Yasuyuki Matsushita; John Wright; Moshe Ben-Ezra; Yu-Wing Tai; Katsushi Ikeuchi

2011-01-01

186

High-resolution ophthalmic imaging system  

SciTech Connect

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

187

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

188

Fundamental constants and high-resolution spectroscopy  

NASA Astrophysics Data System (ADS)

Absorption-line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine-structure constant, ?, and the proton-to-electron mass ratio, ? = m_p/m_e, as measured in remote regions of the Universe to their value today on Earth. In recent years, some evidence has emerged of small temporal and also spatial variations in ? on cosmological scales which may reach a fractional level of ? 10 ppm (parts per million). We are conducting a Large Programme of observations with the Very Large Telescope's Ultraviolet and Visual Echelle Spectrograph (UVES), and are obtaining high-resolution ({R ? 60 000}) and high signal-to-noise ratio (S/N ? 100) spectra calibrated specifically to study the variations of the fundamental constants. We here provide a general overview of the Large Programme and report on the first results for these two constants, discussed in detail in Molaro et al. (2013) and Rahmani et al. (2013). A stringent bound for ??/? is obtained for the absorber at z_abs = 1.6919 towards HE 2217-2818. The absorption profile is complex with several very narrow features, and is modeled with 32 velocity components. The relative variation in ? in this system is +1.3± 2.4_stat ± 1.0_sys ppm if Al II ? 1670 Å and three Fe II transitions are used, and +1.1 ± 2.6_stat ppm in a slightly different analysis with only Fe II transitions used. This is one of the tightest bounds on ?-variation from an individual absorber and reveals no evidence for variation in ? at the 3-ppm precision level (1? confidence). The expectation at this sky position of the recently-reported dipolar variation of ? is (3.2-5.4)±1.7 ppm depending on dipole model used and this constraint of ??/? at face value is not supporting this expectation but not inconsistent with it at the 3? level. For the proton-to-electron mass ratio the analysis of the H_2 absorption lines of the z_abs ? 2.4018 damped Ly? system towards HE 0027-1836 provides ??/? = (-7.6 ± 8.1_stat ± 6.3_sys) ppm which is also consistent with a null variation. The cross-correlation analysis between individual exposures taken over three years and comparison with almost simultaneous asteroid observations revealed the presence of a possible wavelength dependent velocity drift as well as of inter-order distortions which probably dominate the systematic error and are a significant obstacle to achieve more accurate measurements. Based on observations obtained with UVES at the the 8.2 m Kueyen ESO telescope programme L185.A-0745.

Bonifacio, P.; Rahmani, H.; Whitmore, J. B.; Wendt, M.; Centurion, M.; Molaro, P.; Srianand, R.; Murphy, M. T.; Petitjean, P.; Agafonova, I. I.; D'Odorico, S.; Evans, T. M.; Levshakov, S. A.; Lopez, S.; Martins, C. J. A. P.; Reimers, D.; Vladilo, G.

2014-01-01

189

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

190

High resolution electron spin resonance microscopy.  

PubMed

NMR microscopy is routinely employed in fields of science such as biology, botany, and materials science to observe magnetic parameters and transport phenomena in small scale structures. Despite extensive efforts, the resolution of this method is limited (>10 microm for short acquisition times), and thus cannot answer many key questions in these fields. We show, through theoretical prediction and initial experiments, that ESR microscopy, although much less developed, can improve upon the resolution limits of NMR, and successfully undertake the 1 mum resolution challenge. Our theoretical predictions demonstrate that existing ESR technology, along with advanced imaging probe design (resonator and gradient coils), using solutions of narrow linewidth radicals (the trityl family), should yield 64 x 64 pixels 2D images (with z slice selection) with a resolution of 1 x 1 x 10 microm at approximately 60 GHz in less than 1h of acquisition. Our initial imaging results, conducted by CW ESR at X-band, support these theoretical predictions and already improve upon the previously reported state-of-the-art for 2D ESR image resolution achieving approximately 10 x 10 mum, in just several minutes of acquisition time. We analyze how future progress, which includes improved resonators, increased frequency of measurement, and advanced pulsed techniques, should achieve the goal of micron resolution. PMID:14568522

Blank, Aharon; Dunnam, Curt R; Borbat, Peter P; Freed, Jack H

2003-11-01

191

High Resolution Pulse Compression Imaging Using Super Resolution FM-Chirp Correlation Method (SCM)  

NASA Astrophysics Data System (ADS)

This study addresses the issue of the super-resolution pulse compression technique (PCT) for ultrasound imaging. Time resolution of multiple ultrasonic echoes using the FM-Chirp PCT is limited by the bandwidth of the sweep-frequency. That is, the resolution depends on the sharpness of auto-correlation function. We propose the Super resolution FM-Chirp correlation Method (SCM) and evaluate its performance. This method is based on the multiple signal classification (MUSIC) algorithm. Our simulations were made for the model assuming multiple signals reflected from some scatterers. We confirmed that SCM detects time delay of complicated reflected signals successfully with high resolution.

Fujiwara, M.; Okubo, K.; Tagawa, N.

192

Large Scale, High Resolution, Mantle Dynamics Modeling  

NASA Astrophysics Data System (ADS)

To model the geodynamic evolution of plate convergence, subduction and collision and to allow for a connection to various types of observational data, geophysical, geodetical and geological, we developed a 4D (space-time) numerical mantle convection code. The model is based on a spherical 3D Eulerian fem model, with quadratic elements, on top of which we constructed a 3D Lagrangian particle in cell(PIC) method. We use the PIC method to transport material properties and to incorporate a viscoelastic rheology. Since capturing small scale processes associated with localization phenomena require a high resolution, we spend a considerable effort on implementing solvers suitable to solve for models with over 100 million degrees of freedom. We implemented Additive Schwartz type ILU based methods in combination with a Krylov solver, GMRES. However we found that for problems with over 500 thousend degrees of freedom the convergence of the solver degraded severely. This observation is known from the literature [Saad, 2003] and results from the local character of the ILU preconditioner resulting in a poor approximation of the inverse of A for large A. The size of A for which ILU is no longer usable depends on the condition of A and on the amount of fill in allowed for the ILU preconditioner. We found that for our problems with over 5×105 degrees of freedom convergence became to slow to solve the system within an acceptable amount of walltime, one minute, even when allowing for considerable amount of fill in. We also implemented MUMPS and found good scaling results for problems up to 107 degrees of freedom for up to 32 CPU¡¯s. For problems with over 100 million degrees of freedom we implemented Algebraic Multigrid type methods (AMG) from the ML library [Sala, 2006]. Since multigrid methods are most effective for single parameter problems, we rebuild our model to use the SIMPLE method in the Stokes solver [Patankar, 1980]. We present scaling results from these solvers for 3D spherical models. We also applied the above mentioned method to a high resolution (~ 1 km) 2D mantle convection model with temperature, pressure and phase dependent rheology including several phase transitions. We focus on a model of a subducting lithospheric slab which is subject to strong folding at the bottom of the mantle's D" region which includes the postperovskite phase boundary. For a detailed description of this model we refer to poster [Mantel convection models of the D" region, U17] [Saad, 2003] Saad, Y. (2003). Iterative methods for sparse linear systems. [Sala, 2006] Sala. M (2006) An Object-Oriented Framework for the Development of Scalable Parallel Multilevel Preconditioners. ACM Transactions on Mathematical Software, 32 (3), 2006 [Patankar, 1980] Patankar, S. V.(1980) Numerical Heat Transfer and Fluid Flow, Hemisphere, Washington.

Geenen, T.; Berg, A. V.; Spakman, W.

2007-12-01

193

Microscintigraphy with high resolution collimators and radiographic detectors.  

PubMed

The potential use of high resolution collimators with standard radiographic detectors in place of conventional gamma cameras for high resolution microscintigraphy is presented. Polycapillary multiple hole collimators are shown to provide 10-100 micron scale spatial resolution. A series of images from arrays of 125I brachytherapy seeds in Lucite phantoms display resolution better than 0.1 mm with good sensitivity and a 30 mm field of view. In addition to application to brachytherapy seed localization, such "cellular" level resolution is necessary for high-resolution in vivo imaging in mouse models. The system could also enable the use of a wider variety of isotopes, including much lower photon energy isotopes in nuclear medicine, as the high resolution collimator allows more flexibility in detector constraints. PMID:19292006

Mail, N; MacDonald, C A; Gibson, W M

2009-02-01

194

Microscintigraphy with high resolution collimators and radiographic detectors  

SciTech Connect

The potential use of high resolution collimators with standard radiographic detectors in place of conventional gamma cameras for high resolution microscintigraphy is presented. Polycapillary multiple hole collimators are shown to provide 10-100 micron scale spatial resolution. A series of images from arrays of {sup 125}I brachytherapy seeds in Lucite phantoms display resolution better than 0.1 mm with good sensitivity and a 30 mm field of view. In addition to application to brachytherapy seed localization, such ''cellular'' level resolution is necessary for high-resolution in vivo imaging in mouse models. The system could also enable the use of a wider variety of isotopes, including much lower photon energy isotopes in nuclear medicine, as the high resolution collimator allows more flexibility in detector constraints.

Mail, N.; MacDonald, C. A.; Gibson, W. M. [Center for X-ray Optics, University at Albany, Albany, New York 12222 (United States); X-ray Optical System Inc., East Greenbush, New York 12061 (United States)

2009-02-15

195

MAMS: High resolution atmospheric/surface properties  

NASA Technical Reports Server (NTRS)

The Multispectral Atmospheric Mapping Sensor (MAMS) has been used for a number of investigations over the last 8 years. It has served as the basis for retrieval technique development, for atmospheric process studies, and to retrieve geophysical parameters at the surface (land and ocean). It was used most recently to collect high resolution visible and infrared imagery for the CaPE and STORMFEST experiments during FY91 and FY92. The Wildfire spectrometer (similar to MAMS but with different infrared channels) was also used during STORMFEST. The goals of MAMS during CaPE were: (1) to collect MAMS data to support the overall CaPE science objectives; (2) refine techniques for the retrieval of atmospheric moisture and surface geophysical parameters; (3) map the moisture distributions associated with the sea breeze front over Florida with MAMS ancillary satellite data on a case study basis; (4) identify surface features which may serve as local sources of heat and moisture and influence preferential convective regions over Florida, and (5) process MAMS data and derived relevant geophysical parameters to support other CaPE investigators. For STORMFEST both the MAMS and Wildfire spectrometers were used to collect unique multispectral data to study atmospheric processes. The Wildfire objectives were: (1) to collect high quality Wildfire data in conjunction with other in situ and remote measurements available during the STORMFEST field phase (1 February - 15 March 1992); (2) to develop algorithms to retrieve total ozone content and compare with those from TOMS and HIRS (IR); and (3) along with water vapor imagery, use the ozone data to better understand the 3-dimensional structure and dynamics of jet streaks and frontal systems in a case study investigation. The MAMS objectives were: (1) collect MAMS data to support a GSFC investigation of gravity waves; and (2) process the MAMS data to locate gravity wave features, and produce various moisture products in support of the gravity wave investigation. The research activities over the last year are presented and they focused on analyzing the CaPE data sets and collecting and starting preliminary analysis of the STORMFEST MAMS and Wildfire data.

Jedlovec, Gary J.; Guillory, Anthony R.; Carlson, Grant S.; Atkinson, Robert J.

1993-01-01

196

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

197

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

198

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

199

High Resolution Computed Tomography in Asthma  

PubMed Central

Objectives High-resolution computed tomography (HRCT) can detect the structural abnormalities in asthma. This study attempts to correlate these abnormalities with clinical and pulmonary function test (PFT) data. Methods Consecutive stable asthma patients attending Mubarak Al Kabeer Hospital, Kuwait, were subjected to HRCT during a six month period from July 2004 to December 2004, after initial evaluation and PFT. Results Of the 28 cases, sixteen (57.1%) had moderate, 6 (21.4%) had mild and 6 (21.4%) had severe persistent asthma. Thirteen (46.4%) patients had asthma for 1 to 5 years and 12 (42.9%) were having asthma for >10 years. Bronchial wall thickening (57.1%), bronchiectasis (28.6%), mucoid impaction (17.9%), mosaic attenuation (10.7%), air trapping (78.6%) and plate like atelectasis (21.4%) were noted. Bronchial wall thickening (p=0.044) and bronchiectasis (p=0.063) were most prevalent in males. Ten (35.7%) patients exhibited mild, 9 (32.1%) had moderate and 3 (10.7%) had severe air trapping. The difference in Hounsfield units between expiratory and inspiratory slices (air trapping) when correlated with percent-predicted FEV1 in right upper (r=0.25; p=0.30), left upper (r=0.20; p=0.41), right mid (r=0.15; p=0.53), left mid (r=-0.04; p=0.60), right lower (r=0.04; p=0.86) and left lower zones (r=-0.13; p=0.58) showed no relation. The same when correlated as above with the percent predicted FEF 25-75 did not show any significant association. The presence of air trapping was compared with sex (p=0.640), nationality (p=1.000), disease duration (p=1.000) and severity of symptoms (p=0.581). Conclusion Abnormal HRCT findings are common in asthma; however, air trapping when present was not related to the duration or severity of the illness or to the FEV1.

Khadadah, Mousa; Muquim, Abdulaziz; Roberts, Omolara; Sinan, Tariq; Maradny, Nabil; Lasheen, Ibrahim

2012-01-01

200

High-resolution spectrometrometry/interferometer  

NASA Technical Reports Server (NTRS)

Modified double-pass interferometer has several features that maximize its resolution. Proposed for rocket-borne probes of upper atmosphere, it includes cat's-eye retroreflectors in both arms, wedge-shaped beam splitter, and wedged optical-path compensator. Advantages are full tilt compensation, minimal spectrum "channeling," easy tunability, maximum fringe contrast, and even two-sided interferograms.

Breckinridge, J. B.; Norton, R. H.; Schindler, R. A.

1980-01-01

201

High resolution electron spin resonance microscopy  

Microsoft Academic Search

NMR microscopy is routinely employed in fields of science such as biology, botany, and materials science to observe magnetic parameters and transport phenomena in small scale structures. Despite extensive efforts, the resolution of this method is limited (>10?m for short acquisition times), and thus cannot answer many key questions in these fields. We show, through theoretical prediction and initial experiments,

Aharon Blank; Curt R. Dunnam; Peter P. Borbat; Jack H. Freed

2003-01-01

202

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

203

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

204

Identifying network communities with a high resolution  

NASA Astrophysics Data System (ADS)

Community structure is an important property of complex networks. The automatic discovery of such structure is a fundamental task in many disciplines, including sociology, biology, engineering, and computer science. Recently, several community discovery algorithms have been proposed based on the optimization of a modularity function (Q) . However, the problem of modularity optimization is NP-hard and the existing approaches often suffer from a prohibitively long running time or poor quality. Furthermore, it has been recently pointed out that algorithms based on optimizing Q will have a resolution limit; i.e., communities below a certain scale may not be detected. In this research, we first propose an efficient heuristic algorithm QCUT, which combines spectral graph partitioning and local search to optimize Q . Using both synthetic and real networks, we show that QCUT can find higher modularities and is more scalable than the existing algorithms. Furthermore, using QCUT as an essential component, we propose a recursive algorithm HQCUT to solve the resolution limit problem. We show that HQCUT can successfully detect communities at a much finer scale or with a higher accuracy than the existing algorithms. We also discuss two possible reasons that can cause the resolution limit problem and provide a method to distinguish them. Finally, we apply QCUT and HQCUT to study a protein-protein interaction network and show that the combination of the two algorithms can reveal interesting biological results that may be otherwise undetected.

Ruan, Jianhua; Zhang, Weixiong

2008-01-01

205

EDITORIAL: High-resolution noncontact atomic force microscopy High-resolution noncontact atomic force microscopy  

NASA Astrophysics Data System (ADS)

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.

Pérez, Rubén; García, Ricardo; Schwarz, Udo

2009-06-01

206

Broadband multilayer gratings for a high-resolution EUV spectrograph  

NASA Astrophysics Data System (ADS)

Sounding rocket observations of G191-B2B are planned for 1999 January over the bandpass 256-304 angstrom with a high resolution spectrograph. The optical system implements two diffraction gratings with broadband multilayer coatings in a Wadsworth mount. Since the spectral resolution of the experiment will be signal limited, preliminary reflectivity test on test gratings have been performed to determine how high the resolution might be.

Gunderson, Kurt S.; Green, James C.; Wilkinson, Erik; Barbee, Troy W.

1998-08-01

207

Noise analysis of the high resolution methods in ISAR  

Microsoft Academic Search

Commonly used technique for the inverse synthetic aperture radar (ISAR) signal analysis is a two dimensional Fourier transform. Short time intervals could be used in order to reduce nonstationarity effects. However, resolution of images obtained by using short intervals is highly limited. In this case superresolution techniques, such as Capon, ESPRIT and MUSIC, should be used. All high resolution methods

V. Popovic; Thayananthan Thayaparan; L. Stankovic

2005-01-01

208

BUILDING BOUNDARY EXTRACTION FROM HIGH RESOLUTION IMAGERY AND LIDAR DATA  

Microsoft Academic Search

Building boundary data are necessary for the real estate industry, 3D city models and many other applications. In this study, a novel approach integrated high resolution imagery and Lidar data is proposed for automatically obtaining building boundaries with precise geometric position and details. The high resolution images were used to directly extract the building boundaries with precise geometric position, our

Liang Cheng; Jianya Gong; Xiaoling Chen; Peng Han

209

High Resolution, High Capacity, Spatial Specificity in Perceptual Learning  

PubMed Central

Research of perceptual learning has received significant interest due to findings that training on perceptual tasks can yield learning effects that are specific to the stimulus features of that task. However, recent studies have demonstrated that while training a single stimulus at a single location can yield a high-degree of stimulus specificity, training multiple features, or at multiple locations can reveal a broad transfer of learning to untrained features or stimulus locations. We devised a high resolution, high capacity, perceptual learning procedure with the goal of testing whether spatial specificity can be found in cases where observers are highly trained to discriminate stimuli in many different locations in the visual field. We found a surprising degree of location specific learning, where performance was significantly better when target stimuli were presented at 1 of the 24 trained locations compared to when they were placed in 1 of the 12 untrained locations. This result is particularly impressive given that untrained locations were within a couple degrees of visual angle of those that were trained. Given the large number of trained locations, the fact that the trained and untrained locations were interspersed, and the high-degree of spatial precision of the learning, we suggest that these results are difficult to account for using attention or decision strategies and instead suggest that learning may have taken place for each location separately in retinotopically organized visual cortex.

Le Dantec, Christophe C.; Seitz, Aaron R.

2012-01-01

210

Autoradiography for iodine-125 seeds  

SciTech Connect

To study the interior design of model 6702 and 6711 iodine-125 seeds, contact autoradiographs were performed using mammography film. Improved resolution was obtained using a pin-hole camera with a hole of 0.1 mm [times] 0.1 mm. With these techniques, qualitative determination of the relative activity distribution within each seed was possible. The number of the activated resin spheres and the positions of the centers of these spheres can be exactly determined. A model calculation shows that variations in the arrangement of the activated spheres within a seed have a moderate influence on the dose distribution at source distances below 10 mm. Knowing the exact source configuration may be useful when comparing dose calculations with measured data for model 6702 [sup 125]I seeds which are currently employed in ophthalmic plaque and implant therapy of other tumors. 16 refs., 5 figs., 2 tabs.

Alberti, W.; Divoux, S. (Alfried Krupp Krankenhaus, Essen (Germany)); Pothmann, B.; Tabor, P. (Universitaetsklinikum, Essen (Germany)); Hermann, K.P.; Harder, D. (Universitaet Goettingen (Germany))

1993-04-02

211

Medusae Fossae Formation - High Resolution Image  

NASA Technical Reports Server (NTRS)

An exotic terrain of wind-eroded ridges and residual smooth surfaces are seen in one of the highest resolution images ever taken of Mars from orbit. The Medusae Fossae formation is believed to be formed of the fragmental ejecta of huge explosive volcanic eruptions. When subjected to intense wind-blasting over hundreds of millions of years, this material erodes easily once the uppermost tougher crust is breached. The crust, or cap rock, can be seen in the upper right part of the picture. The finely-spaced ridges are similar to features on Earth called yardangs, which are formed by intense winds plucking individual grains from, and by wind-driven sand blasting particles off, sedimentary deposits.

The image was taken on October 30, 1997 at 11:05 AM PST, shortly after the Mars Global Surveyor spacecraft's 31st closest approach to Mars. The image covers an area 3.6 X 21.5 km (2.2 X 13.4 miles) at 3.6 m (12 feet) per picture element--craters only 11 m (36 feet, about the size of a swimming pool) across can be seen. The best Viking view of the area (VO 1 387S34) has a resolution of 240 m/pixel, or 67 times lower resolution than the MOC frame.

Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

1998-01-01

212

HIGH RESOLUTION PHOTOEMISSION STUDIES OF COMPLEX MATERIALS.  

SciTech Connect

Recent instrumentation developments in photoemission are providing new insights into the physics of complex materials. With increased energy and momentum resolution, it has become possible to examine in detail different contributions to the self-energy or inverse lifetime of the photohole created in the photoexcitation process. Employing momentum distribution and energy distribution curves, a detailed study of the optimally doped cuprate, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}, shows that the material behaves like a non-Fermi liquid with no evidence for the quasi-particles characteristic of a Fermi liquid.

JOHNSON,P.D.; VALLA,T.; FEDOROV,A.; REISFELD,G.; HULBERT,S.L.

1999-10-13

213

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

214

DSCOVR High Time Resolution Solar Wind Measurements  

NASA Astrophysics Data System (ADS)

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, A.

2012-12-01

215

One dimension high range resolution profile of terahertz radar  

NASA Astrophysics Data System (ADS)

Step frequency signal is one of the more commonly used radar signal for high range resolution, it commonly used in radar target recognition. The wavelength of Terahertz signal is shorter than that of the microwave, so it is easy to realize the high range resolution. The paper first introduces the step frequency signal to obtain the one-dimensional distance image, and analyze the principle of high resolution range profiles of step frequency radar. Then, the 0.2THz step frequency radar systems are introduced. Finally, the high resolution range profiles are achieved by the simulation of Matlab. The simulation results show that the step frequency THz radar can reach centimeter level high resolution on stationary targets. For moving targets exist distance divergence and coupling shift. With greater speed, the greater the distortion.

Liang, Meiyan; Zeng, Bangze; Zhang, Cunlin; Zhao, Yuejin

2012-12-01

216

High-resolution X-ray Multilayers  

SciTech Connect

Two new approaches are taken in multilayer fabrication to help bridge the gap in bandwidth between traditional multilayers (1 to 2%) and perfect crystals (0.01%). The first approach is based on creating many layers of low-contrast Al2O3/ B4C materials. The second approach is based on using multilayer structures with a small d-spacing using traditional W/B4C and Mo/B4C materials. With 8 keV x-rays on the Chess A2 beamline, we measured a bandwidth of 0.27% with a reflectivity of 40% and a Darwin width of 17 arc seconds from a 26 A d-spacing multilayer with 800 bi-layers of Al2O3/B4C using the low-contrast approach. On the other hand, the short period approach with a W/B4C multilayer and a 14.8 A d-spacing showed a resolution of 0.5 % and a reflectivity of 58.5%. Two more Mo/B4C samples with d-spacings of 15 A and 20 A showed energy resolutions of 0.25% and 0.52% with corresponding reflectivities of 39% and 66%. Thus we observe that both methods can produce useful x-ray optical components.

Martynov, V.V.; Platonov, Yu. [Osmic Inc., 1900 Taylor Rd., Auburn Hills, MI 48326 (United States); Kazimirov, A. [CHESS, Wilson Laboratory, Cornell University, Ithaca, NY 14853 (United States); Bilderback, D.H. [CHESS, Wilson Laboratory, Cornell University, Ithaca, NY 14853 (United States); School of Applied and Engineering, Clark Hall, Cornell University, Ithaca, NY 14853 (United States)

2004-05-12

217

Guided wave arrays for high resolution inspection.  

PubMed

The paper describes a general approach for processing data from a guided wave transducer array on a plate-like structure. The raw data set from such an array contains time-domain signals from each transmitter-receiver combination. The technique is based on linear superposition of signals in the frequency domain with some amplitude and phase factors and can be applied to any array geometry and any types of array elements. The problem of finding optimal coefficients, which allow the best resolution to be achieved with the minimum number of array elements, is investigated. It is shown that improvements in resolution are obtained at the expense of sensitivity to noise. A method of quantifying this sensitivity is presented. Results are shown that illustrate the application of the technique to a linear array and an array of circular geometry (containing a single ring of elements). Experimental data obtained from a guided wave array containing electromagnetic acoustic transducer elements for exciting and detecting the S0 Lamb wave mode in a 5-mm-thick aluminum plate are processed with different algorithms and the results are discussed. Generalization of the technique for the case of multimode media is suggested. PMID:18177150

Velichko, Alexander; Wilcox, Paul D

2008-01-01

218

High Resolution Chemical Study of ALH84001  

NASA Technical Reports Server (NTRS)

We have studied the chemistry of a sample of the SNC meteorite ALH84001 using an environmental scanning electron microscope (ESEM) with an energy dispersive chemical analytical detector and a focused ion beam secondary ion mass spectrometer (FIB-SIMS). Here we present the chemical data, both spectra and images, from two techniques that do not require sample preparation with a conductive coating, thus eliminating the possibility of preparation-induced textural artifacts. The FIB-SIMS instrument includes a column optimized for SEM with a quadrupole type mass spectrometer. Its spatial and spectral resolution are 20 nm and 0.4 AMU, respectively. The spatial resolution of the ESEM for chemical analysis is about 100 nm. Limits of detection for both instruments are mass dependent. Both the ESEM and the FIB-SIMS instrument revealed contrasting surficial features; crumbled, weathered appearance of the matrix in some regions as well as a rather ubiquitous presence of euhedral halite crystals, often associated with cracks or holes in the surface of the rock. Other halogen elements present in the vicinity of the NaCl crystals include K and Br. In this report, elemental inventories are shown as mass spectra and as X-ray maps.

Conrad, Pamela G.; Douglas, Susanne; Kuhlman, Kimberly R.

2001-01-01

219

High Resolution Mapping of Pluto's Albedo Distribution  

NASA Astrophysics Data System (ADS)

This proposal requests time to map Pluto's albedo distribution, using the highest possible resolution of the CYCLE 4 HST. Maps will be made in several key UV and visible bandpasses. Our scientific objectives are to (a) study the distribution of light and dark areas, (b) make the first disk-resolved estimates of Pluto's limb darkening, and (c) compositional discriminate pure from contaminated frost regions. These objectives have not been previously achievable, but are essential to understanding the surface morphology, volatile transport, and the root cause of Pluto's secular lightcurve variations. It may also be possible to detect evidence of the reported limb haze layer(s) in Pluto's atmosphere. These maps will also provide the first direct check on Pluto maps made through indirect techniques. Owing to Pluto's elliptic orbit, we expect the distribution of albedo to change (on a years-to-decade timescale) as Pluto draws away from perihelion and volatile transport proceeds. The proposed observations will document the albedo state at three rotational epochs near the time of perihelion. These maps will be obtained in two colors, by the FOC. No other astronomical instrument has sufficient resolution to accomplish these important scientific objectives.

Stern, S.

1994-07-01

220

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

221

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

222

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

223

High Spectral Resolution With Multilayer Gratings  

NASA Astrophysics Data System (ADS)

The improvement of spectral resolution brought about by the use of multilayer grating (MG) instead of multilayer mirror (MM) is analyzed. The spectrum of a complex sample containing various elements excited under electron irradiation is studied. This sample is a pellet made by pressing powders of Cu and compounds with Fe and F atoms. The MM is a Mo/B4C periodic multilayer with a period of about 6 nm; for the MG a grating of 1 ?m period has been etched in the MM. It is shown that the MG can easily resolve the F K? and Fe L? emissions, separated by about 30 eV, whereas the MM is unable to give such a performance. A comparison with an EDS (SDD) detector is also given. It is also shown that the MG can improve the detection limit. Finally the role of the slit placed in front of the detector is discussed.

André, J.-M.; Le Guen, K.; Jonnard, P.

2010-04-01

224

The ultra high resolution QuikSCAT product  

Microsoft Academic Search

Although QuikSCAT was originally designed to measure winds at a resolution of 25 km, higher resolution wind and rain products have been developed. The 2.5 km ultra high resolution (UHR) products allow QuikSCAT data to be used for applications involving rain, meso-scale phenomena, and in coastal applications. This paper overviews and unifies the various UHR products and discusses their advantages

Brent A. Williams; Michael P. Owen; David G. Long

2009-01-01

225

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 (Dürr 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

226

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 µm, 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

227

High-Resolution MOC Image of Phobos  

NASA Technical Reports Server (NTRS)

This image of Phobos, the inner and larger of the two moons of Mars, was taken by the Mars Global Surveyor on August 19, 1998. This image shows a close-up of the largest crater on Phobos, Stickney, 10 kilometers (6 miles) in diameter. Individual boulders are visible on the near rim of the crater, and are presumed to be ejecta blocks from the impact that formed Stickney. Some of these boulders are enormous - more than 50 meters (160 feet) across. Also crossing at and near the rim of Stickney are shallow, elongated depressions called grooves. This crater is nearly half the size of Phobos and these grooves may be fractures caused by its formation. Phobos was observed by both the Mars Orbiter Camera (MOC) and Thermal Emission Spectrometer (TES). This image is one of the highest resolution images (4 meters or 13 feet per picture element or pixel) ever obtained of the Martian satellite.

Malin Space Science Systems, Inc. and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Thermal Emission Spectrometer is operated by Arizona State University and was built by Raytheon Santa Barbara Remote Sensing. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

1998-01-01

228

High resolution particle spectroscopy in 208Pb  

NASA Astrophysics Data System (ADS)

By using the Q3D magnetic spectrograph of the Maier-Leibnitz-Laboratorium at München, particle-hole states in 208Pb are investigated. With the reaction 208Pb(p, p') at energies 14 < Ep < 18MeV an instrumental resolution of ?Ep'Ep' = 3 · 10-4 is achieved for protons without energy loss in the target. For lower energies Ep' an exponential tail with a width proportional to the effective target thickness appears. Below Ex = 8.2 MeV more than 250 states in 208Pb are observed. Excitation energies are derived with uncertainties of 0.1 keV for strongly excited states by calibration with known data from Nuclear Data Sheets. 208Pb(p, p') via isobaric analog resonances (IAR) in 209Bi allows to determine the neutron particle-hole components of each state in 208Pb. The selective excitation in an IAR yields the parity for each state. Spin and dominant neutron particle-hole configurations of a state are determined from the mean cross section and the shape of the angular distribution for 208Pb(p, p'). From about 120 particle-hole states predicted by the shell model in 208Pb below Ex = 6.1 MeV, about 50 states with negative parity and 30 states with positive parity are identified.

Heusler, A.; Graw, G.; Hertenberger, R.; Wirth, H.-F.; Faestermann, T.; Krücken, R.; Jolie, J.; Scholl, C.; von Brentano, P.

2011-09-01

229

High resolution CO images of Seyfert Galaxies  

NASA Technical Reports Server (NTRS)

The CO (J = 1-0) emission of three Seyfert galaxies, NGC 3227, NGC 7469, and NGC 5033 was imaged. The CO emission in NGC 3227 and NGC 7469 appears as compact structures centered on the active nuclei, containing substantial fractions of the single-dish flux. In NGC 3227, 10 percent of the CO flux detected by the interferometer is contained within the ionized narrow-line region. The unresolved molecular gas concentrations in the nucleus of NGC 3227 imply a CO mass of 65 million solar masses concentrated within a diameter less than 50 pc. The CO emission in NGC 5033 is not detected at this resolution, implying a CO structure size of 20 to 60 arcsec. Continuum emission at 2.7 mm is not detected in any of the three galaxies. In the center of NGC 7469, the H2 mass is comparable to the dynamical mass. Kinematic studies of the detected gas reveal a rotational motion of the gas in NGC 3227 and NGC 7469, allowing identification of the gas in NGC 7469 with a nuclear starburst. These data are consistent with the idea that interactions between galaxies cause gas to concentrate in their nuclei thereby feeding starburst and Seyfert activity.

Meixner, M.; Puchalsky, R.; Blitz, L.; Wright, M.

1990-01-01

230

Road Extraction from High Resolution Satellite Images  

NASA Astrophysics Data System (ADS)

Roads are significant objects of an infrastructure and the extraction of roads from aerial and satellite images are important for different applications such as automated map generation and change detection. Roads are also important to detect other structures such as buildings and urban areas. In this paper, the road extraction approach is based on Active Contour Models for 1-meter resolution gray level images. Active Contour Models contains Snake Approach. During applications, the road structure was separated as salient-roads, non-salient roads and crossings and extraction of these is provided by using Ribbon Snake and Ziplock Snake methods. These methods are derived from traditional snake model. Finally, various experimental results were presented. Ribbon and Ziplock Snake methods were compared for both salient and non-salient roads. Also these methods were used to extract roads in an image. While Ribbon snake is described for extraction of salient roads in an image, Ziplock snake is applied for extraction of non-salient roads. Beside these, some constant variables in literature were redefined and expressed in a formula as depending on snake approach and a new approach for extraction of crossroads were described and tried.

Özkaya, M.

2012-07-01

231

High-Resolution Fluorometer for Mapping Microscale Phytoplankton Distributions  

PubMed Central

A new high-resolution, in situ profiling fluorometer maps fluorescence distributions with a spatial resolution of 0.5 to 1.5 mm to a depth of 70 m in the open ocean. We report centimeter-scale patterns for phytoplankton distributions associated with gradients exhibiting 10- to 30-fold changes in fluorescence in contrasting marine ecosystems.

Doubell, Mark J.; Seuront, Laurent; Seymour, Justin R.; Patten, Nicole L.; Mitchell, James G.

2006-01-01

232

High-Resolution Urban Image Classification Using Extended Features.  

National Technical Information Service (NTIS)

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 with...

R. R. Vatsavai

2013-01-01

233

Very high resolution optical spectrometry by stimulated Brillouin scattering  

Microsoft Academic Search

In this letter, we demonstrate very high-resolution optical spectrometry based on stimulated Brillouin scattering between a swept-tuned laser and a test optical signal. Measurement principles are presented along with spectral measurements of unmodulated and modulated optical sources showing 0.08-pm resolution and 80-dB dynamic range.

J. M. Subías Domingo; J. Pelayo; F. Villuendas; C. D. Heras; E. Pellejer

2005-01-01

234

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

235

Demonstration of ultra high resolution soft x-ray tomography  

NASA Astrophysics Data System (ADS)

Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows which were separated by ~ 5?m. Depth resolution comparable to the transverse resolution was achieved by recording nine 2-D images of the object at angles between -50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3-D image using an algebraic reconstruction technique (ART) algorithm. We observed a transverse resolution of ~1000 A?. Artifacts in the reconstruction limited the overall depth resolution to ~6000 A?, however some features were clearly reconstructed with a depth resolution of ~1000 A?.

Haddad, W. S.; McNulty, I.; Trebes, J. E.; Anderson, E. H.; Yang, L.; Brase, J. M.

1995-05-01

236

High-resolution spectrographs on medium-diameter telescopes  

NASA Astrophysics Data System (ADS)

The problem of high-resolution spectroscopic observations on telescopes with diameters of D = 0.5-1.5 m is considered. Examples of the optimum technical solutions and survivability of certain telescopes and methods of observation are given in retrospect. Improvements in the technique of spectroscopy allow one to also consider the potential of those instruments that were not originally intended for use in high-resolution spectroscopy. Arguments in favor of using medium-diameter telescopes in modern high-resolution spectroscopy are discussed. This review is connected to the 100th anniversary of the 122-cm telescope of the Crimean Astrophysical Observatory.

Panchuk, V. E.; Klochkova, V. G.

2013-06-01

237

High resolution extreme ultraviolet (EUV) studies of the sun  

NASA Astrophysics Data System (ADS)

We briefly discuss some of the currently unanswered problems in solar astronomy which lend themselves to investigations particularly in the Extreme Ultra Violet (EUV) region of the spectrum. In this context, need of high spatial, spectral and temporal resolution is emphasized for such studies. Finally, after a brief discussion of the EUV instrumentation, a high resolution stigmatic EUV spectroheliometer is described which is currently under development for high resolution studies of the solar chromosphere, transition region and corona. The spectroheliometer will be flown aboard a sounding rocket.

Jain, Surendra K.

1992-01-01

238

High resolution cytogenetic evaluation of couples with recurring fetal wastage.  

PubMed

Both high resolution and routine chromosome analyses were used to study couples with a history of two or more spontaneous abortions in early pregnancy. In the 20 couples studied, two of the women were found to have an inversion. One paracentric inversion, (13)(q13.1q22.3), was apparent on routine analysis. The small pericentric inversion (11)(p11.12q12.3), was only detected by high resolution techniques. Given the low yield and increased cost and effort involved, we do not believe that high resolution studies are justified for screening couples with repeated abortions. PMID:3980017

Yang-Feng, T L; Finley, S C; Finley, W H; Francke, U

1985-01-01

239

High Resolution X-Ray Explorer (HIREX)  

NASA Technical Reports Server (NTRS)

SAO has carried out a study to determine the feasibility of building an orbiting telescope capable of resolving 7 km structure on the Sun. In order to achieve the required imaging the telescope must have a resolution 0.01 arcsec. This fact challenges the state of the art of orbiting telescopes in several areas: mirror figuring; optical metrology; optical mounting; mirror figure control; system alignment; optical stability; observatory pointing; and image stability image stability. The telescope design concept is based on a 0.6m Cassegrain-style telescope with a 240 meter effective focal length. This is achieved with 2 mirrors supported at opposite ends of a 27 m space-deployable boom. The telescope mirrors are coated with multilayers designed to reflect a broad XUV passband. A third, small mirror, near the focal plane performs the function of selecting the narrow band that is finally imaged. Image stabilization to the 0.005 a,rcsec level is achieved by active control of the secondary mirror. The primary mirror is held unadjustably to the spacecraft, its pointing set by the space- craft orientation. The secondary mirror is mounted on a 6-axis stage that permits its position to be changed to align the telescope in space. The stage is intended for intermittent adjustment, both because of its speed of travel, and the TBD alignment procedure. The third mirror is called the TXI (Tuneable X-ray Imager). It is mounted on a gimbal that permits it to be tipped over a 60 degree range, selecting between the individual wavelengths in the initial bandpass. It can also rotated completely out of the way to allow the full, broadband EUV flux to strike the focal plane.

Golub, Leon

1999-01-01

240

A high resolution global scale groundwater model  

NASA Astrophysics Data System (ADS)

Groundwater is the world's largest accessible source of fresh water. It plays a vital role in satisfying needs for drinking water, agriculture and industrial activities. During times of drought groundwater sustains baseflow to rivers and wetlands, thereby supporting ecosystems. Most global scale hydrological models (GHMs) do not include a groundwater flow component, mainly due to lack of geohydrological data at the global scale. For the simulation of lateral flow and groundwater head dynamics a realistic physical representation of the groundwater system is needed, especially for GHMs that run at finer resolution. In this study we present a global scale groundwater model (run at 6' as dynamic steady state) using MODFLOW to construct an equilibrium water table at its natural state as the result of long-term climatic forcing. The aquifer schematization and properties were based on available global datasets of lithology and transmissivities combined with estimated aquifer thickness of an upper unconfined aquifer. The model is forced with outputs from the land-surface model PCR-GLOBWB, specifically with net recharge and surface water levels. A sensitivity analysis, in which the model was run with various parameter settings, showed variation in saturated conductivity causes most of the groundwater level variations. Simulated groundwater heads were validated against reported piezometer observations. The validation showed that groundwater depths are reasonably well simulated for many regions of the world, especially for sediment basins (R2 = 0.95). The simulated regional scale groundwater patterns and flowpaths confirm the relevance of taking lateral groundwater flow into account in GHMs. Flowpaths show inter-basin groundwater flow that can be a significant part of a basins water budget and helps to sustain river baseflow, explicitly during times of droughts. Also important aquifer systems are recharged by inter-basin groundwater flows that positively affect water availability.

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

2014-05-01

241

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 (1280×3×1024) 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

2012-05-01

242

High Resolution X-Ray Explorer (HIREX)  

NASA Technical Reports Server (NTRS)

SAO is involved in a study to determine the feasibility of building an orbiting telescope capable of resolving 7 km structure on the Sun. In order to achieve the required imaging the telescope must have a resolution 0.01 arcsec. This fact challenges the state of the art of orbiting telescopes in several areas: Mirror Figuring; Optical Metrology; Optical Mounting; Mirror Figure Control; System Alignment; Optical Stability; Observatory Pointing; and Image Stability. The telescope design concept is based on a 0.6 m Gregorian-style telescope with a 240 meter effective focal length. This is achieved with 2 mirrors supported at opposite ends of a 35 m space-deployable boom. The telescope mirrors are coated with multilayers designed to reflect a broad XUV passband. A third, small mirror, near the focal plane performs the function of selecting the narrow band that is finally imaged. Image stabilization to the 0.005 arcsec level is achieved by active control of the secondary mirror. The primary mirror is held unadjustably to the spacecraft, its pointing set by the spacecraft orientation. The secondary mirror is mounted on a 6-axis stage that permits its position to be changed to align the telescope in space. The stage is intended for intermittent adjustment, both because of its speed of travel, and the TBD alignment procedure. The third mirror is called the TXI (Tuneable X-ray Imager). It is mounted on a gimbal that permits it to be tipped over a 60 degree range, selecting between the individual wavelengths in the initial bandpass. It can also rotated completely out of the way to allow the full, broadband EUV flux to strike the focal plane. Finally, the focal plane assembly is designed to rotate on the outer edge of a circle centered on the TXI mirror rotation axis. This permits the focal plane to move to the location that the TXI redirects the light once it has been set to a given wavelength response. The Engineering Study is divided into the following areas: Mirror Fabrication and Metrology; Optical Layout-Trade Study between On-axis and Off-axis; Overall System Design; and Pointing Control/Image Stabilization. The observational goals of the mission are described in the Mission Requirements document. The work is being performed to the requirements called out in the Science Requirements document.

Goulb, Leon

1997-01-01

243

High time-resolution sprite observations  

Microsoft Academic Search

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.

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

2007-01-01

244

Twoaxis electromagnetic microscanner for high resolution displays  

Microsoft Academic Search

A novel microelectromechanical systems (MEMS) actuation technique is developed for retinal scanning display and imaging applications allowing effective drive of a two-axes scanning mirror to wide angles at high frequency. Modeling of the device in mechanical and electrical domains, as well as the experimental characterization is described. Full optical scan angles of 65deg and 53deg are achieved for slow (60

Arda D. Yalcinkaya; Hakan Urey; Dean Brown; Tom Montague; Randy Sprague

2006-01-01

245

Techniques for Providing High Spatial Resolution from Radar Altimeters.  

National Technical Information Service (NTIS)

The requirements for making satellite altimeter measurements with high spatial resolution and over a broad swath are reviewed. It is shown that off-nadir altimetry poses very difficult problems in spacecraft pointing and radar echo interpretation, and tha...

H. D. Griffiths C. G. Rapley

1986-01-01

246

The Advanced X-ray Astrophysics Facility high resolution camera  

NASA Astrophysics Data System (ADS)

The HRC (High Resolution Camera) is a photon counting instrument to be flown on the Advanced X-Ray Astrophysics Facility (AXAF). It is a large field of view, high angular resolution, detector for the X-ray telescope. The HRC consists of a CsI coated microchannel plate (MCP) acting as a soft X-ray photocathode, followed by a second MCP for high electronic gain. The MCPs are readout by a crossed grid of resistively coupled wires to provide high spatial resolution along with timing and pulse height data. The instrument will be used in two modes, as a direct imaging detector with a limiting sensitivity of 10 to the -15th ergs/sq cm sec in a 10 to the 5th second exposure, and as a readout for an objective transmission grating providing spectral resolution of several hundreds to thousands.

Murray, Stephen S.; Chappell, Jon H.

247

The very high resolution scanning radiometer of the FY-1  

NASA Astrophysics Data System (ADS)

The very high resolution scanning radiometer of the FY-1 meteorological satellite is considered. Attention is given to detection principles, instrument design, data processing, and operational performance in orbit, and picture quality.

1991-01-01

248

Texture Models for High-Resolution Ocean Microwave Imagery.  

National Technical Information Service (NTIS)

Computer simulations of ocean passive microwave images and texture features are developed in the context of high-resolution radiometric observations. The technique is based on statistical and deterministic characterizations of spatial-variable fields (ima...

V. Raizer

2005-01-01

249

Gabor Segmentation of High Resolution Synthetic Aperture Radar Imagery.  

National Technical Information Service (NTIS)

This thesis investigates the use of Gabor filters and a radial basis function (RBF) network for segmentation of high resolution (1 foot by 1 foot) synthetic aperture radar (SAR) imagery. Processing involved correlation between the SAR imagery and Gabor fu...

M. A. Hazlett

1991-01-01

250

High Angular Resolution Microwave Sensing with Large, Sparse, Random Arrays.  

National Technical Information Service (NTIS)

This document describes progress toward development of a general capability for high resolution microwave surveillance and imaging using large, sparse, self-cohering arrays. During the last five years progress has been made in the following areas: underst...

C. N. Dorny

1983-01-01

251

High Resolution Imaging of Circumstellar Disks at Millimeter Wavelengths  

NASA Technical Reports Server (NTRS)

We summarize progress on our program to use high angular resolution imaging of thermal dust continuum emission at millimeter and submillimeter wavelengths to probe the structure of protoplanetary disks and debris disks around nearby stars.

Wilner, David J.

2004-01-01

252

A high resolution SPECT detector based on thin continuous LYSO  

NASA Astrophysics Data System (ADS)

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 2 mm thick continuous Lutetium Yttrium Orthosilicate (LYSO) scintillator and compare it to the performance of a 5 mm thick continuous NaI(Tl) scintillator. The advantages of LYSO are its high stopping power and its non-hygroscopicity. Drawbacks are 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 (99mTc, 140 keV) 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 (0.93 mm full width at half maximum (FWHM)) is superior to the spatial resolution of the NaI(Tl) detector (1.37 mm FWHM). The intrinsic radioactivity in the energy window (42% window centered at 140 keV) 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.

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

2014-01-01

253

Performance characteristics of high resolution Compton telescopes  

NASA Astrophysics Data System (ADS)

To build upon the goals of the upcoming INTEGRAL mission, the next generation soft gamma -ray (0.2-20 MeV) observatory will require improved sensitivity to continuum and nuclear line emission, while maintaining high spectroscopy to resolve Doppler shifts and broadenings. We present the simulated performance of two germanium Compton telescope (GCT) designs in high Earth orbit conditions. The goal of this work is both to determine realistic sensitivities for the GCTs, as well as determine the geometry which best takes advantage of the spectral, imaging, and stopping power of germanium detectors. We find that a novel Compact design optimizes the sensitivity to both nuclear line and continuum sources, with an effective factor of 2.0 improvement over a Classical design. The Compact GCT would provide an order of magnitude improvement in sensitivity over INTEGRAL.

Boggs, S. E.; Jean, P.

2001-09-01

254

Microbeam X-Ray Standing Wave and High Resolution Diffraction  

SciTech Connect

Post-focusing collimating optics are introduced as a tool to condition X-ray microbeams for the use in high-resolution X-ray diffraction and scattering techniques. As an example, a one-bounce imaging capillary and miniature Si(004) channel-cut crystal were used to produce a microbeam with 10 {mu}m size and an ultimate angular resolution of 2.5 arc sec. This beam was used to measure the strain in semiconductor microstructures by using X-ray high resolution diffraction and standing wave techniques to {delta}d/d < 5x10-4.

Kazimirov, A.; Bilderback, D.H.; Huang, R. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); Sirenko, A. [New Jersey Institute of Technology, Department of Physics, Newark, NJ 07102 (United States)

2004-05-12

255

High-resolution knife-edge laser beam profiling  

Microsoft Academic Search

A knife-edge method for profiling focused and unfocused laser beams with a high spatial resolution is presented. High resolution is achieved by dithering the knife-edge in the scan direction. The method is equivalent to the slit method but with a variable slit width also on a sub-?m scale. A signal-to-noise ratio of 106 : 1 has been demonstrated. The design

W. Plass; R. Maestle; K. Wittig; A. Voss; A. Giesen

1997-01-01

256

Mid-infrared high-resolution spectrograph for SPICA  

Microsoft Academic Search

We present a preliminary optical design and layout for the mid-infrared (4-18 mum) high-resolution spectrograph for SPICA, Japanese next-generation space IR observatory with 3.5 m telescope. MIR high-resolution spectroscopy is a powerful probe to study gas-phase molecules\\/atoms in a variety of astronomical objects. Space observation provides a great opportunity to study many molecular lines especially in between the atmospheric windows.

Naoto Kobayashi; Yuji Ikeda; Hideyo Kawakita; Keigo Enya; Takao Nakagawa; Hirokazu Kataza; Hideo Matsuhara; Yasuhiro Hirahara; Hitoshi Tokoro

2008-01-01

257

Towards a high-resolution global coupled navy prediction system  

Microsoft Academic Search

A fully coupled global atmosphere-ocean prediction system for short-term forecasting has been developed at NRL Monterey at modestly high horizontal resolution (0.5° ocean and 0.75° atmosphere). University and national laboratory partners are performing coupled ice\\/ocean simulations, improving the data assimilation scheme, and running high-resolution ocean simulations with the goal of advancing this prediction system. Sea ice in the 0.4° global

Julie L. McClean; Prasad Thoppil; Detelina Ivanova; Donald Stark; Mathew Maltrud; E. Hunke; P. May; J. Carton; B. Giese

2004-01-01

258

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

259

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

260

Detailed analysis of the TIMES and TIMES0 high-resolution MAS methods for high-resolution proton NMR  

NASA Astrophysics Data System (ADS)

We analyze and compare the specifications of TIMES and TIMES0 proton high-resolution NMR methods for solid-state samples. This comparison is performed in terms of resolution versus magic-angle spinning (MAS) spinning speed, ?R, rf-field amplitude, ?1, and tilt-angle for the effective rf-field, ?p. The chemical-shift and homo-nuclear dipolar scaling factors are calculated for both methods. For all MAS speeds, the best resolution is always observed with rf-field of ?1 ? 120-130 kHz. At slow MAS speed (?R ? 10 kHz), the best resolution is observed for a tilt-angle of ?P ? 90°. At moderate spinning speed (15 ? ?R ? 35 kHz), ?P ? 55° gives the best resolution. At higher MAS speed (?R ? 60 kHz), with TIMES and TIMES0 the best resolution is obtained for ?P ? 40°; but we then recommend TIMES0, owing to its simpler set-up. We also show that in addition to the usual high rf-field regime (?1 ? 120-130 kHz), another low rf-regime (?1 ? 40-50 kHz) exists at MAS speed higher than ?R ? 60 kHz, which also gives a good 1H resolution. This low rf-regime should be useful for multi-dimensional analyses of bio-molecules with 1H detection under high-resolution, in order to limit the heating of the sample.

Lu, Xingyu; Lafon, Olivier; Trébosc, Julien; Thankamony, Aany Sofia Lilly; Nishiyama, Yusuke; Gan, Zhehong; Madhu, P. K.; Amoureux, Jean-Paul

2012-10-01

261

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

262

Multi-Resolution Variational Analysis (MRVA): High-resolution data fusion over global surface  

NASA Astrophysics Data System (ADS)

The Multi-Resolution Variational Analysis method was developed to merge satellite sea surface temperature (SST) measurements with drastically different spatial resolution and coverage. MRVA is a hybrid of the variational analysis technique used commonly in geophysical data interpolation/assimilation and multiresolution analysis technique based on orthonormal wavelet decomposition, where the former addresses the irregular-sampling and uncertainty estimation issues while the latter provides a mathematical framework to control the interpolation scale (internal resolution) for each data set as well as inter-sensor bias corrections. Satellite-based SST data are indeed irregularly-sampled by different sensor types. The microwave (MW) sensors have typically coarser 25-km resolution than the infra-red (IR) sensors which can resolve down to a 1-km scale. However, the IR-based measurements are prone to data voids due to cloud contamination, which does not affect MW sensors nearly as much. Scientific and operational needs for the SST data cover a wide range of spatial and temporal scales. For example, a regional or global mean is often examined over a long time period in climate studies, while SST snapshots of sub-kilometer resolution may be required in biological applications. The focus of the Multi-scale Ultra-high Resolution (MUR) SST analysis project is to produce a high-resolution daily SST field based on the satellite retrieval data to address these variety of needs. The MRVA method was applied to merge these satellite data to produce the MUR SST analysis over a 1-km global grid at a daily frequency. The power spectral density of SST displays a self-similar (power-law) characteristic, and MUR SST shows consistency with this characteristic over a wider range of wavenumber spectrum due to its higher internal resolution. Capability to reproduce such empirical characteristics is a strength of the MRVA technique.

Chin, T. M.

2012-12-01

263

High-resolution imaging using ultrasound-modulated optical tomography  

NASA Astrophysics Data System (ADS)

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 ?m wide area below the sample surface. With this configuration, the length of the ultrasonic pulses determines the axial resolution, and the lateral resolution results from the width of the ultrasonic beam at the focus. Diffuse light reflected from the sample is collected into a fiber and the modulated component is separated from the background by a confocal Fabry-Perot interferometer. Using this setup, high contrast images are obtained of 100 ?m wide pieces of hair that are buried one millimeter below the surface of the tissue-mimicking sample. It is the first time, to the authors' knowledge, that images with such high resolution have been obtained using ultrasound-modulated optical tomography in the reflection mode.

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

2004-07-01

264

Microbeam High Angular Resolution Diffraction Applied to Optoelectronic Devices  

SciTech Connect

Collimating perfect crystal optics in a combination with the X-ray focusing optics has been applied to perform high angular resolution microbeam diffraction and scattering experiments on micron-size optoelectronic devices produced by modern semiconductor technology. At CHESS, we used capillary optics and perfect Si/Ge crystal(s) arrangement to perform X-ray standing waves, high angular-resolution diffraction and high resolution reciprocal space mapping analysis. At the APS, 2ID-D microscope beamline, we employed a phase zone plate producing a beam with the size of 240 nm in the horizontal plane and 350 nm in the vertical (diffraction) plane and a perfect Si (004) analyzer crystal to perform diffraction analysis of selectively grown InGaAsP and InGaAlAs-based waveguides with arc sec angular resolution.

Kazimirov, A.; Bilderback, D. H. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY, 14853 (United States); Sirenko, A. A. [Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Cai, Z.-H.; Lai, B. [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, IL 60439 (United States)

2007-01-19

265

HIGH RESOLUTION ANALOG / DIGITAL POWER SUPPLY CONTROLLER  

SciTech Connect

Corrector magnets for the SPEAR-3 synchrotron radiation source require precision, high-speed control for use with beam-based orbit feedback. A new Controller Analog/Digital Interface card (CANDI) has been developed for these purposes. The CANDI has a 24-bit DAC for current control and three 24-bit {Delta}-{Sigma} ADCs to monitor current and voltages. The ADCs can be read and the DAC updated at the 4 kHz rate needed for feedback control. A precision 16-bit DAC provides on-board calibration. Programmable multiplexers control internal signal routing for calibration, testing, and measurement. Feedback can be closed internally on current setpoint, externally on supply current, or beam position. Prototype and production tests are reported in this paper. Noise is better than 17 effective bits in a 10 mHz to 2 kHz bandwidth. Linearity and temperature stability are excellent.

Medvedko, Evgeny A

2003-05-21

266

Alpha-particle autoradiography in CR-39: The determination of the microdistribution of activity and trace element analysis  

NASA Astrophysics Data System (ADS)

New and elaborate techniques for alpha-particle autoradiography of thick specimens based on the plastic nuclear track detector CR-39 have been developed. These permit a full analysis of both trace element and microdistribution of alpha-active nuclides present. The important features of the techniques are: (1) reliable low level counting down to 10 -15Ci g -1, (2) high resolution alpha-particle spectroscopy in CR-39, (3) determination of the absolute abundance of alpha active nuclides present in the specimen, (4) determination of the distribution of emission with height up to 30 microns above the surface of the autoradiograph, (5) the local determination of the radon diffusion coefficient in the specimen which is needed to calculate the activity levels of 222Rn and daughter nuclei, (6) the analysis of small and large clusters of alpha-particle activity recorded on the autoradiograph. These techniques are briefly discussed.

Peter Fews, A.; Henshaw, Denis L.

267

High-Resolution Presentation Environment Using Multi Displays  

Microsoft Academic Search

In this paper, a high-resolution presentation system using PC clusters and multiple displays for various applications including 3D virtual reality system, large scale geographic presentation and high definition video conference system is introduced. Conventional virtual reality systems use a highend graphics engine and a polyhedral display equipment to realize high immersive VR environment. However, those hardware devices are so expensive

Go Chiba; Tomoyuki Ishida; Yoshitaka Shibata

2008-01-01

268

Dual camera system for acquisition of high resolution images  

NASA Astrophysics Data System (ADS)

Video surveillance is ubiquitous in modern society, but surveillance cameras are severely limited in utility by their low resolution. With this in mind, we have developed a system that can autonomously take high resolution still frame images of moving objects. In order to do this, we combine a low resolution video camera and a high resolution still frame camera mounted on a pan/tilt mount. In order to determine what should be photographed (objects of interest), we employ a hierarchical method which first separates foreground from background using a temporal-based median filtering technique. We then use a feed-forward neural network classifier on the foreground regions to determine whether the regions contain the objects of interest. This is done over several frames, and a motion vector is deduced for the object. The pan/tilt mount then focuses the high resolution camera on the next predicted location of the object, and an image is acquired. All components are controlled through a single MATLAB graphical user interface (GUI). The final system we present will be able to detect multiple moving objects simultaneously, track them, and acquire high resolution images of them. Results will demonstrate performance tracking and imaging varying numbers of objects moving at different speeds.

Papon, Jeremie A.; Broussard, Randy P.; Ives, Robert W.

2007-02-01

269

High-resolution neutron microtomography with noiseless neutron counting detector  

NASA Astrophysics Data System (ADS)

The improved collimation and intensity of thermal and cold neutron beamlines combined with recent advances in neutron imaging devices enable high-resolution neutron radiography and microtomography, which can provide information on the internal structure of objects not achievable with conventional X-ray imaging techniques. Neutron detection efficiency, spatial and temporal resolution (important for the studies of dynamic processes) and low background count rate are among the crucial parameters defining the quality of radiographic images and tomographic reconstructions. The unique capabilities of neutron counting detectors with neutron-sensitive microchannel plates (MCPs) and with Timepix CMOS readouts providing high neutron detection efficiency (˜70% for cold neutrons), spatial resolutions ranging from 15 to 55 ?m and a temporal resolution of ˜1 ?s—combined with the virtual absence of readout noise—make these devices very attractive for high-resolution microtomography. In this paper we demonstrate the capabilities of an MCP-Timepix detection system applied to microtomographic imaging, performed at the ICON cold neutron facility of the Paul Scherrer Institute. The high resolution and the absence of readout noise enable accurate reconstruction of texture in a relatively opaque wood sample, differentiation of internal tissues of a fly and imaging of individual ˜400 ?m grains in an organic powder encapsulated in a ˜700 ?m thick metal casing.

Tremsin, A. S.; McPhate, J. B.; Vallerga, J. V.; Siegmund, O. H. W.; Feller, W. B.; Lehmann, E.; Butler, L. G.; Dawson, M.

2011-10-01

270

A miniature high-resolution accelerometer utilizing electron tunneling  

NASA Technical Reports Server (NTRS)

New methods have been developed to implement high-resolution position sensors based on electron tunneling. These methods allow miniaturization while utilizing the position sensitivity of electron tunneling to give high resolution. A single-element tunneling accelerometer giving a displacement resolution of 0.002 A/sq rt Hz at 10 Hz, corresponding to an acceleration resolution of 5 x 10 exp -8 g/sq rt Hz, is described. A new dual-element tunneling structure which overcomes the narrow bandwidth limitations of a single-element structure is described. A sensor with an operating range of 5 Hz to 10 kHz, which can have applications as an acoustic sensor, is discussed. Noise is analyzed for fundamental thermal vibration of the suspended masses and is compared to electronic noise. It is shown that miniature tunnel accelerometers can achieve resolution such that thermal noise in the suspended masses is the dominant cause of the resolution limit. With a proof mass of order 100 mg, noise analysis predicts limiting resolutions approaching 10 exp -9 g/sq rt Hz in a 300 Hz band and 10 exp -8 g/sq rt Hz at 1 kHz.

Rockstad, Howard K.; Kenny, T. W.; Reynolds, J. K.; Kaiser, W. J.; Vanzandt, T. R.; Gabrielson, Thomas B.

1992-01-01

271

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

272

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

273

Development and Characteristic Evaluation of High Resolution SQUID Magnetometer  

NASA Astrophysics Data System (ADS)

High resolution SQUID magnetometers had previously been developed which was designed for nerves, muscles, slices of brain tissue and small animals. In these SQUID system, diameters of the pickup coil were a few mm and the distances between the pickup coil and the outside surface of the dewer was a few mm. In this study, we developed a super high resolution SQUID magnetometer having higher spatial resolution than previous systems. In this system, diameter of the pickup coil is 200 µm, the distance between the pickup coil and the outside surface of the dewar is 800 µm. The typical system noise in the magnetic shielded room is 2.7pT/?Hz in the frequency from 1Hz to 10kHz. We discuss features of the measurement system and the spatial resolution of this SQUID system using a current source model. It can be discriminated extreme of magnetic field pattern obtained from the meander line of 500 µm interval.

Kobayashi, Koichiro; Hashimoto, Hidehito; Kawakatsu, Masaki; Uchikawa, Yoshinori

274

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 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC, Berkeley /LBL, Berkeley /Cambridge U. /Royal Holloway, U. of London /Cornell U., LNS /LLNL, Livermore /University Coll. London /SLAC /Caltech /KEK, Tsukuba

2007-06-08

275

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

276

Identifying new opportunities for exoplanet characterisation at high spectral resolution  

NASA Astrophysics Data System (ADS)

Context. Recently, there have been a series of detections of molecules in the atmospheres of extrasolar planets using high spectral resolution (R ~ 100 000) observations, mostly using the CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the Very Large Telescope. These measurements are able to resolve molecular bands into individual absorption lines. Observing many lines simultaneously as their Doppler shift changes with time allows the detection of specific molecules in the atmosphere of the exoplanet. Aims: We aim to identify new ways of increasing the planet signal in these kinds of high-resolution observations. First of all, we wish to determine what wavelength settings can best be used to target certain molecules. Furthermore, we want to simulate exoplanet spectra of the day-side and night-side to see whether night-side observations are feasible at high spectral resolution. Methods: We performed simulations of high-resolution CRIRES observations of a planet's thermal emission and transit between 1 and 5 ?m and performed a cross-correlation analysis on these results to assess how well the planet signal can be extracted. These simulations take into account telluric absorption, sky emission, realistic noise levels, and planet-to-star contrasts. We also simulated day-side and night-side spectra at high spectral resolution for planets with and without a day-side temperature inversion, based on the cases of HD 189733b and HD 209458b. Results: Several small wavelength regions in the L-band promise to yield cross-correlation signals from the thermal emission of hot Jupiters of H2O, CH4, CO2, C2H2, and HCN that can exceed those of the current detections by up to a factor of 2-3 for the same integration time. For transit observations, the H-band is also attractive, with the H, K, and L-bands giving cross-correlation signals of similar strength. High-resolution night-side spectra of hot Jupiters can give cross-correlation signals as high as the day-side, or even higher. Conclusions: We show that there are many new possibilities for high-resolution observations of exoplanet atmospheres that have expected planet signals at least as high as those already detected. Hence, high-resolution observations at well-chosen wavelengths and at different phases can improve our knowledge about hot Jupiter atmospheres significantly, already with currently available instrumentation.

de Kok, R. J.; Birkby, J.; Brogi, M.; Schwarz, H.; Albrecht, S.; de Mooij, E. J. W.; Snellen, I. A. G.

2014-01-01

277

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

278

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

279

High-resolution 157-nm laser micromachining of polymers  

Microsoft Academic Search

An Exitech Microstepper exposure tool has been used to laser micromachine a variety of polymeric materials with high resolution at a wavelength of 157 nm. We have demonstrated it is possible to machine thin film materials, different photoresists and fluorine-based polymers with submicron accuracy and resolution. The tool used for this work incorporated a 36x 0.5 NA Schwarzschild lens to

Philipp Gruenewald; Julian S. Cashmore; Jim Fieret; Malcolm C. Gower

2001-01-01

280

Applications of high-resolution remote sensing image data  

NASA Technical Reports Server (NTRS)

There are many situations in which the image resolution of satellite data is insufficient to provide the detail required for resource management and environmental monitoring. This paper will focus on applications of high-resolution (0.4 to 10 m) airborne multispectral and imaging spectrometer data acquired in Canada using the MEIS II multispectral line imager and the PMI imaging spectrometer. Applications discussed will include forestry, mapping, and geobotany.

Strome, W. M.; Leckie, D.; Miller, J.; Buxton, R.

1990-01-01

281

A new paradigm for high resolution 3D lithography  

Microsoft Academic Search

A new gray-scale lithography method and modeling approach are reported, providing a technique for high-resolution 3D micromachining. A double-exposure grayscale technique was developed showing a significant improvement in the vertical resolution compared to single- exposure gray-scale lithography. This technique increased the number of gray-scale height levels from n levels to n levels, which decreased the average step height from 0.19

L. A. Mosher; C. M. Waits; B. Morgan; R. Ghodssi

2008-01-01

282

Ocular Imaging Combining Ultrahigh Resolution and High Speed OCT  

NASA Astrophysics Data System (ADS)

The impact of ultrahigh-resolution and ultrahigh-speed OCT technique on corneal and retinal imaging is shown. The capabilities of advanced OCT system for imaging of the cornea and the thickness determination of the tear film, corneal epithelium, and Bowman's layer over a wide field of view are demonstrated. The high transverse and axial resolution of OCT system allowing one to image individual nerve fiber bundles, the parafoveal capillary network, and individual cone photoreceptors is described.

Schmoll, Tilman; Leitgeb, Rainer A.

283

Mars 1:500k high resolution map bases  

Microsoft Academic Search

The Mars 1:500k map bases are high-resolution black and white digital photomosaics generated to support the Mars Geologic Mapping Program. The Viking Orbiter images are used to map areas of scientific interest. The final products provided to the mapper include a cutline plot indicating image location and resolution, digital files, and a package consisting of a brownline, cronapaque, cronaflex, ozalid,

E. M. Lee; K. Edwards; A. Grecu; B. Redding; A. Wasserman; A. Bennett

1997-01-01

284

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

285

CsI(Na) Scintillation Plate with High Spatial Resolution  

Microsoft Academic Search

A two dimensional CsI(Na) scintillation plate with high spatial resolution has been developed by growing CsI(Na) crystal on a special fiber plate with fiber size of 20 ¿m. The number of photons at the output were 34 photons for 55Fe and 260 photons for 129I respectively. The spatial resolution measured by electron beam excitation showed approximately 30 ¿m of FWHM.

Michihiro Ito; Masahiro Yamaguchi; Koichiro Oba

1987-01-01

286

Studies on the quantitative autoradiography. II. Radioluminography for quantitative autoradiography of 3H.  

PubMed

The process of obtaining 3H-autoradiographic (ARG) images has been expected for a long time. A few X-ray films with no protection layer are commercially available, however, they do not give a reliable image which can be quantitated and can give good contrast. We tried to fabricate a 3H-type sensor which has no protection layer on a highly sensitive sensor, and called it Imaging plate (IP). The IP is composed of one of the specially designed photo-stimulable phosphors containing of BaFX: Eu2+(X = Cl, Br or I) crystals. Results indicated a good contrast and reliable whole-body ARG image of 3H-labelled glucose with trial IP, which has never been obtained with any X-ray films even if these were subjected to a long exposure time. The ARG image can be displayed by either black-and-white hard copy or a colored one with the digital display representing relative intensity of photostimulated luminescence (PSL) without back ground (BG) or relative intensity concentration ((PSL-BG)/S), where S was equivalent to 100 pixels (1 mm2). Similarly to the experimental results of 14C, the linear relationship relative intensity and radioactivity of the 3H standard sources was demonstrated with a very wide range of 10(2) to 10(5) dpm/mg upon the exposure for 7d. Also the relationship between relative intensity and relative exposure (radioactivity x exposure time) was linear within the latitude of relative intensity 10(1) to 10(5) (PSL-BG). The trial IP was particularly effective for the quantitative autoradiography of TLC plates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7735259

Motoji, N; Hayama, E; Shigematsu, A; Tazaki, S; Mori, N; Miyahara, J

1995-01-01

287

Digital pulse processing in high resolution, high throughput, gamma-ray spectroscopy  

Microsoft Academic Search

A new method for processing signals produced by high resolution, large volume semiconductor detectors is described. These detectors, to be used in the next generation of spectrometer arrays for nuclear research (i.e., EUROBALL, etc.), present a set of problems, such as resolution degradation due to charge trapping and ballistic deficit effects, poor resolution at a high count rate, long term

Andrey Georgiev; Werner Gast

1993-01-01

288

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

289

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

290

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

291

High-Resolution Association Mapping of Atherosclerosis Loci in Mice  

PubMed Central

Objective To fine map previously identified quantitative trait loci (QTL) affecting atherosclerosis in mice using association analysis. Methods and Results We recently showed that high-resolution association analysis using common inbred strains of mice is feasible if corrected for population structure. To utilize this approach for atherosclerosis, which requires a sensitizing mutation, we bred human apoB100 transgenic mice with 22 different inbred strains to produce F1 heterozygotes. Mice carrying the dominant transgene were tested for association with high-density SNP maps. Here we focus on high-resolution mapping of the previously described Ath30 locus on Chr 1. As compared to the previous linkage analysis, association improved the resolution of the Ath30 locus by more than an order of magnitude. Using expression quantitative trait locus analysis, we identified one of the genes in the region, Des, as a strong candidate. Conclusions Our high-resolution mapping approach accurately identifies and fine maps known atherosclerosis QTL. These results suggest that high-resolution genome-wide association analysis for atherosclerosis is feasible in mice.

Bennett, Brian J.; Orozco, Luz; Kostem, Emrah; Erbilgin, Ayca; Dallinga, Marchien; Neuhaus, Isaac; Guan, Bo; Wang, Xuping; Eskin, Eleazar; Lusis, Aldons J.

2012-01-01

292

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

293

High-resolution electromagnetic altimetry over the ocean  

Microsoft Academic Search

A pair of coils acting as transmitter and receiver of a harmonic electromagnetic (EM) wave is found to be an excellent high-resolution altimeter at low altitudes over ocean regions. Due to high seawater conductivity, the altimetric determination from a received signal is computationally simple. Experimental results obtained from the Cape Cod Bay area indicate that an EM altimeter may be

I. J. WON

1986-01-01

294

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

295

High Resolution Forward And Inverse Earthquake Modeling on Terascale Computers  

Microsoft Academic Search

For earthquake simulations to play an important role in the reduction of seismic risk, they must be capable of high resolution and high fidelity. We have developed algorithms and tools for earthquake simulation based on multiresolution hexahedral meshes. We have used this capability to carry out 1 Hz simulations of the 1994 Northridge earthquake in the LA Basin using 100

Volkan Akcelik; Jacobo Bielak; George Biros; Ioannis Epanomeritakis; Antonio Fernandez; Omar Ghattas; Eui Joong Kim; Julio C. López; David R. O'Hallaron; Tiankai Tu; John Urbanic

2003-01-01

296

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

297

High-resolution structure of viruses from random diffraction snapshots  

PubMed Central

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 nano-crystalline objects.

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

2014-01-01

298

High-resolution structure of viruses from random diffraction snapshots.  

PubMed

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 nano-crystalline objects. PMID:24914154

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

2014-07-17

299

High-Resolution Room Temperature Spectroscopy with Lanthanum Halides  

SciTech Connect

The most desirable features in a spectroscopic material are high sensitivity and high resolution. Cerium-activated crystals of lanthanum bromide (LaBr{sub 3}:Ce) have higher sensitivity and better spectroscopic resolution than sodium/cesium iodide (NaI/CsI) crystals because of higher density (5.29 g/cm{sup 3}), faster decay time (35 ns), minimal afterglow, and larger (63 000 photons/MeV) and more linear light output (6% nonlinearity over the energy range between 60 and 1332 keV). Of all the recent scintillator materials manufactured to date, LaBr{sub 3}, with cerium activators, is one of the most promising for high-resolution, fast timing techniques as applied to medical image reconstructions or associated particle imaging.

Mukhopadhyay, Sanjoy [Bechtel Nevada (United States)

2005-11-15

300

High-resolution electromagnetic altimetry over the ocean  

NASA Astrophysics Data System (ADS)

A pair of coils acting as transmitter and receiver of a harmonic electromagnetic (EM) wave is found to be an excellent high-resolution altimeter at low altitudes over ocean regions. Due to high seawater conductivity, the altimetric determination from a received signal is computationally simple. Experimental results obtained from the Cape Cod Bay area indicate that an EM altimeter may be superior in resolution to a radar altimeter. Because of its wide beamwidth, the EM altimeter measures the distance to the instantaneous mean sea level and ignores ripples and waves. This may be considered an advantage over a laser altimeter which, despite its high resolution, is susceptible to noise caused by small surface fluctuations (due to its small beamwidth). The method has potential application to determining the sea-ice thickness.

Won, I. J.

1986-04-01

301

The theory and practice of high resolution scanning electron microscopy  

SciTech Connect

Recent advances in instrumentation have produced the first commercial examples of what can justifiably be called High Resolution Scanning Electron Microscopes. The key components of such instruments are a cold field emission gun, a small-gap immersion probe-forming lens, and a clean dry-pumped vacuum. The performance of these microscopes is characterized by several major features including a spatial resolution, in secondary electron mode on solid specimens, which can exceed 1nm on a routine basis; an incident probe current density of the order of 10{sup 6} amps/cm{sup 2}; and the ability to maintain these levels of performance over an accelerating voltage range of from 1 to 30keV. This combination of high resolution, high probe current, low contamination and flexible electron-optical conditions provides many new opportunitites for the application of the SEM to materials science, physics, and the life sciences. 27 refs., 14 figs.

Joy, D.C. (Tennessee Univ., Knoxville, TN (USA) Oak Ridge National Lab., TN (USA))

1990-01-01

302

Hirims: A High Resolution IR Spectrometer Proposed For Juice  

NASA Astrophysics Data System (ADS)

HIRIMS is a high spectral resolution spectrometer proposed for the ESA-led JUICE mission. Its spectral range covers the 2.6- to 4.75-micron window at a sampled spectral resolution power of 10,000. It can operate both in nadir, limb and solar occultation modes. Its scientific objectives comply with the scientific objectives of the JUICE mission: 1. Study the dynamics and the chemistry of Jupiter's atmosphere with an emphasis on the upper and middle atmosphere, its relations with the Jupiter environment; 2. Study the exospheres of the icy Galilean satellites: their sources and sinks, and their relations with the jovian environment; 3. Study the evolution of icy satellites surfaces in a high radiation environment and link the surface composition with interior processes; 4. Monitor Io's activity and atmosphere. The presentation will highlight the unique measurements a high resolution IR spectrometer can perform to address JUICE scientific objectives and investigations.

Fouchet, Thierry; HIRIMS Team

2012-10-01

303

High spatial resolution measurements of ram accelerator gas dynamic phenomena  

NASA Astrophysics Data System (ADS)

High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

1992-07-01

304

Broadband THz high-resolution interferometry using coherent synchrotron radiation  

NASA Astrophysics Data System (ADS)

In storage rings, short electron bunches can produce an intense THz radiation called Coherent Synchrotron Radiation (CSR). The flux of this emission between 250 and 750 GHz is very advantageous for spectroscopy, but intensity fluctuations lead to artifacts in the FTIR spectra and, until now, prevented the use of CSR for high-resolution measurements. At SOLEIL, we found stable CSR conditions for which the signal-to-noise ratio (S/N) allows for measurements at high resolution. Moreover, we developed an artifact correction system, based on a simultaneous detection of the input and the output signals of the interferometer, which allows improving further the signal-to-noise ratio. The stable CSR combined with this ingenious technique allowed us to record for the first time high-resolution FTIR spectra in the sub-THz range, with an exceptional S/N of 100 in a few hours.

Barros, J.; Manceron, L.; Brubach, J.-B.; Evain, C.; Couprie, M.-E.; Tordeux, M.-A.; Labat, M.; Bielawski, S.; Szwaj, C.; Ursu, R.; Roy, P.

2012-10-01

305

High-resolution streaming video integrated with UGS systems  

NASA Astrophysics Data System (ADS)

Imagery has proven to be a valuable complement to Unattended Ground Sensor (UGS) systems. It provides ultimate verification of the nature of detected targets. However, due to the power, bandwidth, and technological limitations inherent to UGS, sacrifices have been made to the imagery portion of such systems. The result is that these systems produce lower resolution images in small quantities. Currently, a high resolution, wireless imaging system is being developed to bring megapixel, streaming video to remote locations to operate in concert with UGS. This paper will provide an overview of how using Wifi radios, new image based Digital Signal Processors (DSP) running advanced target detection algorithms, and high resolution cameras gives the user an opportunity to take high-powered video imagers to areas where power conservation is a necessity.

Rohrer, Matthew

2010-04-01

306

New vacuum solar telescope and observations with high resolution  

NASA Astrophysics Data System (ADS)

The New Vacuum Solar Telescope (NVST) is a one meter vacuum solar telescope that aims to observe fine structures on the Sun. The main goals of NVST are high resolution imaging and spectral observations, including measurements of the solar magnetic field. NVST is the primary ground-based facility used by the Chinese solar research community in this solar cycle. It is located by Fuxian Lake in southwest China, where the seeing is good enough to perform high resolution observations. We first introduce the general conditions at the Fuxian Solar Observatory and the primary science cases of NVST. Then, the basic structures of this telescope and instruments are described in detail. Finally, some typical high resolution data of the solar photosphere and chromosphere are also shown.

Liu, Zhong; Xu, Jun; Gu, Bo-Zhong; Wang, Sen; You, Jian-Qi; Shen, Long-Xiang; Lu, Ru-Wei; Jin, Zhen-Yu; Chen, Lin-Fei; Lou, Ke; Li, Zhi; Liu, Guang-Qian; Xu, Zhi; Rao, Chang-Hui; Hu, Qi-Qian; Li, Ru-Feng; Fu, Hao-Wen; Wang, Feng; Bao, Men-Xian; Wu, Ming-Chan; Zhang, Bo-Rong

2014-06-01

307

High-resolution spectra of dark interstellar clouds  

NASA Astrophysics Data System (ADS)

The paper presents brand new spectra acquired with the aid of the coude echelle spectrometer installed at the coude focus of the 2-m telescope at Terskol Peak. Very high resolution (R =500 000), available since very recently, allows analysis of profile shapes of interstellar absorption spectral features. The latter are either very sharp (if originated in gas atoms or simple molecules) or show very complicated profiles (unidentified diffuse interstellar bands - DIBs). DIBs are believed to originate in complex, carbon-bearing molecules, possibly present in dark interstellar clouds. An analysis of their high-resolution profiles seems to be the most prospective way to identify the carriers of these puzzling spectral features.

Krelowski, J.; Galazutdinov, G.; Musaev, F.

2003-04-01

308

High resolution collimator system for X-ray detector  

DOEpatents

High resolution in an X-ray computerized tomography (CT) inspection system is achieved by using a collimator/detector combination to limit the beam width of the X-ray beam incident on a detector element to the desired resolution width. In a detector such as a high pressure Xenon detector array, a narrow tapered collimator is provided above a wide detector element. The collimator slits have any desired width, as small as a few mils at the top, the slit width is easily controlled, and they are fabricated on standard machines. The slit length determines the slice thickness of the CT image.

Eberhard, Jeffrey W. (Schenectady, NY); Cain, Dallas E. (Scotia, NY)

1987-01-01

309

Design and test of a High-Resolution EUV Spectroheliometer  

NASA Technical Reports Server (NTRS)

The HiRES High-Resolution EUV Spectroheliometer is a sounding rocket instrument yielding very high spatial, spectral, and temporal resolution images of the solar outer atmosphere, on the basis of a 45-cm Gregorian telescope feeding a normal-incidence stigmatic EUV spectrometer with imaging multianode microchannel-array detector system, as well as an IR spectrometer with imaging CCD detector system. Attention is given to the expected performance of this system, including the effects of vibrational misalignments due to the sounding rocket flight environment.

Berger, Thomas E.; Timothy, J. G.; Walker, Arthur B. C., Jr.; Kirby, Helen; Morgan, Jeffrey S.; Jain, Surendra K.; Saxena, Ajay K.; Bhattacharyya, Jagadish C.; Huber, Martin C. E.; Tondello, Giuseppe

1992-01-01

310

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

311

High time resolution laser induced fluorescence in pulsed argon plasma  

SciTech Connect

A submillisecond time resolution laser induced fluorescence (LIF) method for obtaining the temporal evolution of the ion velocity distribution function in pulsed argon plasma is presented. A basic LIF system that employs a continuous laser wave pumping and lock-in aided detection of the subsequent fluorescence radiation is modified by addition of a high frequency acousto-optic modulator to provide measurements of the ion flow velocity and ion temperature in a helicon generated pulsed argon plasma with temporal resolutions as high as 30 {mu}s.

Biloiu, Ioana A.; Sun Xuan; Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

2006-10-15

312

Simulation of imaging effects of very high resolution SAR systems  

NASA Astrophysics Data System (ADS)

Current space borne synthetic aperture radar (SAR) systems are able to provide users with high resolution image data of around one meter. Focusing on systems operating in the X-band, this value is not the end of possible improvements in resolution. There still lies a great potential in an increase of bandwidth of the radar signal itself and also in a significant enlargement of the synthetic aperture. From the technical point of view this certainly is a challenge, but could be possible for future space borne SAR missions already with current state of the art hardware. As a matter of proof TerraSAR-X introduces a new staring spotlight image product that significantly improves the azimuthal resolution to around a quarter of a meter. The technical realization of the very high resolution SAR system is not the only obstacle to overcome. Especially the increase of Doppler bandwidth along the synthetic aperture requests special treatment and considerations in system design from a signal processing's point of view. Challenges like orbital accuracy, tropospheric effects, approximations in SAR processing methods and depth-of-focus issues have to be addressed. In this paper, most of these challenges are studied separately by performing parametric simulations for single point targets and also for complex signatures of an airplane. A comparable SAR parameter set as used by the high resolution sliding spotlight mode and the new staring spotlight mode of TerraSAR-X are used for simulation.

Anglberger, H.; Speck, R.; Suess, H.

2013-10-01

313

High Resolution Simulations of Future Climate in West Africa Using a Variable-Resolution Atmospheric Model  

NASA Astrophysics Data System (ADS)

In previous work demonstrated the application of a var¬iable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM), across a wide range of spatial and time scales to investigate the ability of the model to provide realistic simulations of present-day climate and plausible projections of future climate change over sub-Saharan Africa. By applying the model in stretched-grid mode the versatility of the model dynamics, numerical formulation and physical parameterizations to function across a range of length scales over the region of interest, was also explored. We primarily used CCAM to illustrate the capability of the model to function as a flexible downscaling tool at the climate-change time scale. Here we report on additional long term climate projection studies performed by downscaling at much higher resolutions (8 Km) over an area that stretches from just south of Sahara desert to the southern coast of the Niger Delta and into the Gulf of Guinea. To perform these simulations, CCAM was provided with synoptic-scale forcing of atmospheric circulation from 2.5 deg resolution NCEP reanalysis at 6-hourly interval and SSTs from NCEP reanalysis data uses as lower boundary forcing. CCAM 60 Km resolution downscaled to 8 Km (Schmidt factor 24.75) then 8 Km resolution simulation downscaled to 1 Km (Schmidt factor 200) over an area approximately 50 Km x 50 Km in the southern Lake Chad Basin (LCB). Our intent in conducting these high resolution model runs was to obtain a deeper understanding of linkages between the projected future climate and the hydrological processes that control the surface water regime in this part of sub-Saharan Africa.

Adegoke, J. O.; Engelbrecht, F.; Vezhapparambu, S.

2013-12-01

314

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 (SAR’s) 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 (UAV’s) 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

315

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

316

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

317

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

318

Remote sensing cloud properties from high spectral resolution infrared observations  

NASA Technical Reports Server (NTRS)

A technique for estimating cloud radiative properties (spectral emissivity and reflectivity) in the IR is developed based on observations at a spectral resolution of approximately 0.5/cm. The algorithm uses spectral radiance observations and theoretical calculations of the IR spectra for clear and cloudy conditions along with lidar-determined cloud-base and cloud-top pressure. An advantage of the high spectral resolution observations is that the absorption effects of atmospheric gases are minimized by analyzing between gaseous absorption lines. The technique is applicable to both ground-based and aircraft-based platforms and derives the effective particle size and associated cloud water content required to satisfy, theoretically, the observed cloud IR spectra. The algorithm is tested using theoretical simulations and applied to observations made with the University of Wisconsin's ground-based and NASA ER-2 aircraft High-Resolution Infrared Spectrometer instruments.

Smith, William L.; Ma, Xia L.; Ackerman, Steven A.; Revercomb, H. E.; Knuteson, R. O.

1993-01-01

319

Parallelization and Algorithmic Enhancements of High Resolution IRAS Image Construction  

NASA Technical Reports Server (NTRS)

The Infrared Astronomical Satellite caried out a nearly complete survey of the infrared sky, and the survey data are important for the study of many astrophysical phenomena. However, many data sets at other wavelengths have higher resolutions than that of the co-added IRAS maps, and high resolution IRAS images are strongly desired both for their own information content and their usefulness in correlation. The HIRES program was developed by the Infrared Processing and Analysis Center (IPAC) to produce high resolution (approx. 1') images from IRAS data using the Maximum Correlation Method (MCM). We describe the port of HIRES to the Intel Paragon, a massively parallel supercomputer, other software developments for mass production of HIRES images, and the IRAS Galaxy Atlas, a project to map the Galactic plane at 60 and 100(micro)m.

Cao, Yu; Prince, Thomas A.; Tereby, Susan; Beichman, Charles A.

1996-01-01

320

Detection with high resolution radar - Great promise, big challenge  

NASA Astrophysics Data System (ADS)

An approach to improving the radar sensitivity against low radar-cross-section (RCS) and stealth targets without requiring very large power-aperture products is proposed. The problem of target detection performed by a high-resolution radar is discussed, and it is shown that imaging can improve radar sensitivity by a proper design of both transmitter and receiver. In essence, the technique is regarded as an attempt to achieve a perfect equalization of the composite channel formed by the transmitter, antenna, target response, and receiver. An outline of the design criteria for the optimization of the transmitter and receiver in noise-limited conditions is presented. An assessment of the detection performance of a high-resolution radar and a comparison with a low-resolution radar are made for a simple case involving the use of a coherent pulse train as a radar waveform.

Farina, Alfonso; Studer, Flavio A.

1991-05-01

321

Science with High Spatial Resolution Far-Infrared Data  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

322

Unsupervised Feature Learning for High-Resolution Satellite Image Classification  

SciTech Connect

The rich data provided by high-resolution satellite imagery allow us to directly model geospatial neighborhoods by understanding their spatial and structural patterns. In this paper we explore an unsupervised feature learning approach to model geospatial neighborhoods for classification purposes. While pixel and object based classification approaches are widely used for satellite image analysis, often these approaches exploit the high-fidelity image data in a limited way. In this paper we extract low-level features to characterize the local neighborhood patterns. We exploit the unlabeled feature measurements in a novel way to learn a set of basis functions to derive new features. The derived sparse feature representation obtained by encoding the measured features in terms of the learned basis function set yields superior classification performance. We applied our technique on two challenging image datasets: ORNL dataset representing one-meter spatial resolution satellite imagery representing five land-use categories and, UCMERCED dataset consisting of 21 different categories representing sub-meter resolution overhead imagery. Our results are highly promising and, in the case of UCMERCED dataset we outperform the best results obtained for this dataset. We show that our feature extraction and learning methods are highly effective in developing a detection system that can be used to automatically scan large-scale high-resolution satellite imagery for detecting large-facility.

Cheriyadat, Anil M [ORNL

2013-01-01

323

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.

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

2013-01-01

324

Upcoming challenges in high-resolution CT below 1 ?m  

NASA Astrophysics Data System (ADS)

Besides the pixel size of the detector and the size of the focal spot the resolution of a computed tomography (CT) setup depends especially on the spatial stability of all components. In this publication we present the performance of our sub-?-CT components and the limitations resulting from spatial instability of the system. We will show that it is possible to overcome these limitations and reach resolution in the range of 500 nm. The experimental setup is based on high-resolution imaging detectors, a multifocus X-ray tube and a high-precision manipulation system. Our research contains measurements of the effective focal spot size using a resolution test mask and of the long-term stability of the focal spot position due to thermal expansion of the focusing unit. Also the stability of the X-ray intensity that affects the quality of CT will be corrected by additional bright image correction during the measurement. Due to the measured instabilities correction of the original images is necessary to achieve highest resolution. Solutions and results will be presented.

Salamon, M.; Burtzlaff, S.; Voland, V.; Sukowski, F.; Uhlmann, N.

2009-08-01

325

Environmental high resolution electron microscopy and applications to chemical science  

Microsoft Academic Search

An environmental cell high resolution electron microscope (EHREM) has been developed for in situ studies of dynamic chemical reactions on the atomic scale. It allows access to metastable intermediate phases of catalysts and to sequences of reversible microstructural and chemical development associated with the activation, deactivation and poisoning of a catalyst. Materials transported through air can be restored or recreated

E. D. Boyes; P. L. Gai

1997-01-01

326

High Resolution Spectrum Estimation of FMCW Radar Signals  

Microsoft Academic Search

This paper presents a comparative study of high resolution spectral estimation methods applied to Frequency Modulated Continuous Wave (FMCW) radar data; autoregressive (AR), Prony, and, Eigenanalysis-based methods are briefly reviewed. A comparison of spectral lines detection capabilities between methods for different signal to noise ratio (SNR) and modal amplitudes is made using numerical experiments. Computer simulations have been made using

Michel Bouchard; D. Gingras; Y. de Villers; D. Potvin

1994-01-01

327

INTERVAL CARRIER FREE ELECTROPHORESIS FOR HIGH RESOLUTION PROTEIN PURIFICATION  

Microsoft Academic Search

Interval free flow zone electrophoresis is a new mode of free flow zone electrophoresis (FFZE), which facilitates purification of proteins and other molecular substances at very high resolution. It can be performed in the commercially available free flow electrophoresis (FFE) apparatus Octopus. The specimens are loaded and unloaded as usual with the help of a thin buffer film flowing between

Johann Bauer; Gerhard Weber

1998-01-01

328

High-Resolution Nuclear Magnetic Resonance of Solids.  

ERIC Educational Resources Information Center

Examines recent developments in techniques for obtaining high-resolution nuclear magnetic resonance (NMR) spectra on solid samples, discussing the kinds of applications for which these techniques are well suited. Also discusses the characteristics of NMR of solids and generating magnetization for NMR in solids. (JN)

Maciel, Gary E.

1984-01-01

329

HIGH-RESOLUTION ATMOSPHERIC ENSEMBLE MODELING AT SRNL  

Microsoft Academic Search

The High-Resolution Mid-Atlantic Forecasting Ensemble (HME) is a federated effort to improve operational forecasts related to precipitation, convection and boundary layer evolution, and fire weather utilizing data and computing resources from a diverse group of cooperating institutions in order to create a mesoscale ensemble from independent members. Collaborating organizations involved in the project include universities, National Weather Service offices, and

R. Buckley; D. Werth; S. Chiswell; B. Etherton

2011-01-01

330

High resolution, 2-dimensional shear stress measurements from imaging polarimetry  

Microsoft Academic Search

Here we present a novel method for obtaining high-resolution, 2-dimensional shear stress measurements over aerodynamic surfaces, based upon the dynamic birefringence of a shear sensitive, liquid crystal coating. Air flowing over the surface of a liquid crystal coating causes a measurable change in the birefringence of the coating that is dependent upon the magnitude of the shear stress of the

Fletcher Kimura; Werner Kaminsky; Gamal Khalil; James Riley; James Callis

2004-01-01

331

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

332

The benefits of high resolution mass spectrometry in environmental analysis.  

PubMed

The benefits of high resolution mass spectrometry (HRMS) are well known and widely realized in various applications; however, HRMS is very rarely utilized in environmental GC/MS analyses. It is assumed that low resolution GC/MS provides adequate and reliable results in the majority of cases dealing with priority pollutants and other volatile and semivolatile compounds. As environmental issues become more and more important in modern society and new generations of high resolution and high mass accuracy mass spectrometers become available, it is quite reasonable to expect improvements in sensitivity, reliability and quantity of information provided by GC/MS analyses. This article demonstrates the advantages of high resolution GC/MS for qualitative and quantitative environmental analyses including targeted and non-targeted approaches as well as de novo structural elucidation of analytes not present in commercial libraries. Most of the examples presented here involve the GC/MS analysis of snow samples collected in 2012 and 2013 in Moscow, Russia. PMID:24087826

Lebedev, Albert T; Polyakova, Olga V; Mazur, Dmitry M; Artaev, Viatcheslav B

2013-11-21

333

High Resolution Powder Diffractometer at ISIS: An Introductory Users Guide,  

National Technical Information Service (NTIS)

The manual is intended to fulfill the role of an introductory guide for users of a high resolution powder diffractometer (HRPD). In addition to providing a general overview of the machine, the manual will help users to run the instrument routinely and han...

W. I. F. David D. E. Akporiaye R. M. Ibberson C. C. Wilson

1988-01-01

334

High-resolution imaging using lucky frame selection  

Microsoft Academic Search

This paper reports on progress towards the development of an imaging methodology which has potential for producing high-resolution imagery that has not been degraded by atmospheric turbulence. The technique relies on a well known concept called 'lucky frame selection', although uses a radically different approach. Rather than using an image based metric to determine image quality we have proposed the

S C Woods; J G Burnett; P J Kent; A J Turner

2008-01-01

335

Sun and Nearby Stars: Microwave Observations at High Resolution.  

National Technical Information Service (NTIS)

High-resolution microwave observations are providing new insights into the nature of active regions and eruptions on the sun and nearby stars. The strength, evolution, and structure of magnetic fields in coronal loops can be determined by multiple-wavelen...

K. R. Lang M. R. Kundu

1985-01-01

336

High Resolution Gas Phase Infrared Absorption Spectra of Simple Gases.  

National Technical Information Service (NTIS)

A study has been made of the infrared spectra of simple gases under conditions of very high resolution. Most of the measurements have been made in the spectral region between 2000-400/cm. The molecules which have been studied are CS2, ethylene, methylfluo...

J. Overend

1973-01-01

337

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

338

Measuring snow microstructure and hardness using a high resolution penetrometer  

Microsoft Academic Search

Using a high resolution snow penetrometer we are able to measure snow penetration resistance and snow meso- and microstructure. The variation of the signal is characteristic for different snow types. The penetrometer can be used in the field as well in the laboratory. The range of snow types which can be tested extends from light new snow (50 kg m?3)

Martin Schneebeli; Christine Pielmeier; Jerome B Johnson

1999-01-01

339

HIGH RESOLUTION G-BANDED CHROMOSOMES OF THE MOUSE  

EPA Science Inventory

High resolution G-banded mouse chromosomes were prepared using an actinomycin D and acridine orange pretreatment protocol, resulting in late prophase mouse chromosomes which reveal over twice the number of bands as compared to mid-metaphase. These elongated chromosomes, described...

340

High spatial resolution radar altimetry for global Earth topography mapping  

Microsoft Academic Search

This paper summarises the work performed by Alenia Aerospazio in the design of new radar altimeter systems suitable for high spatial resolution Earth topography observation. The instrument concept proposed is based on the application of synthetic aperture processing and interferometric techniques to a conventional Ku band pulse limited system. The major design features and expected performance are briefly presented

G. Angino; F. Impagnatiello; C. Zelli

1997-01-01

341

High resolution observations of 150 km echoes at Jicamarca  

Microsoft Academic Search

High resolution soundings of equatorial upper E-region echoes at Jicamarca exhibit gravity wave modulated signal intensity distributions and Doppler velocities corresponding to vertical plasma drifts. A gravity wave wind driven interchange instability is suggested as a possible generation mechanism of the field-aligned plasma irregularities responsible for the echoes. The echoes may be utilized in gravity wave studies and in zonal

Erhan Kudeki; Clinton D. Fawcett

1993-01-01

342

High resolution SAR processing using stepped-frequencies  

Microsoft Academic Search

This paper demonstrates a method to produce high resolution SAR images using stepped-frequencies. An advantage of the stepped-frequency approach is the reduction of the instantaneous bandwidth and sampling rate requirements of the radar system, as well as the possibility of skipping frequencies that might be corrupted due to external interfering frequency sources. The technique described involves the construction of a

Richard T. Lord; Michael R. Inggs

1997-01-01

343

Forward-Looking High-Resolution GPR System.  

National Technical Information Service (NTIS)

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

J. Kositsky P. Milanfar

1999-01-01

344

High resolution HAXPES and status of the VOLPE project  

NASA Astrophysics Data System (ADS)

The status of the Volume PhotoEmission (VOLPE) project, now operational at ESRF, is reviewed. Commissioning phase and test experiments confirm that high energy resolution (71 meV at 5934 eV kinetic energy) with truly bulk sensitivity is achievable in Hard X-ray Photoelectron Spectroscopy (HAXPES) experiments.

Panaccione, G.; Cautero, G.; Fondacaro, A.; Grioni, M.; Lacovig, P.; Monaco, G.; Offi, F.; Paolicelli, G.; Sacchi, M.; Stefani, G.; Torelli, P.

2005-07-01

345

Comparison of classification approaches for high-range resolution radar  

Microsoft Academic Search

A radar scattering model was used to provide targets for a classification study of high range resolution radar signatures. Intrinsic dimensionality of these signatures was calculated using kth nearest neighbor information. Two classifier paradigms were implemented, a Gaussian classifier and a synthetic discriminant function classifier. The Gaussian correlation classifier was more robust in the presence of white Gaussian noise while

Clayton V. Stewart; Victor J. Larson; James D. Halsey

1992-01-01

346

High resolution parametric description of slow wave sleep  

Microsoft Academic Search

We propose a new framework for quantitative analysis of sleep EEG, compatible with the traditional analysis, based upon adaptive time–frequency approximation of signals. Using a high resolution description of EEG rhythms and transients in terms of their time occurrence and width, frequency and amplitude, we present a detailed detection and parameterization of delta waves, including also the time occupied by

Piotr J. Durka; Urszula Malinowska; Waldemar Szelenberger; Andrzej Wakarow; Katarzyna J. Blinowska

2005-01-01

347

Application of Classification Models to Pharyngeal High-Resolution Manometry  

ERIC Educational Resources Information Center

Purpose: The authors present 3 methods of performing pattern recognition on spatiotemporal plots produced by pharyngeal high-resolution manometry (HRM). Method: Classification models, including the artificial neural networks (ANNs) multilayer perceptron (MLP) and learning vector quantization (LVQ), as well as support vector machines (SVM), were…

Mielens, Jason D.; Hoffman, Matthew R.; Ciucci, Michelle R.; McCulloch, Timothy M.; Jiang, Jack J.

2012-01-01

348

Scene Classification Using High Spatial Resolution Multispectral Data.  

National Technical Information Service (NTIS)

Spectral imagery has traditionally been an important tool for terrain categorization (TERCAT), High-spatial resolution (8-meter), 4-color MSI data from IKONOS provide a new tool for scene classification, The utility of these data are studied for the purpo...

J. J. Garner

2002-01-01

349

Human enamel structure studied by high resolution electron microscopy  

SciTech Connect

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

Wen, S.L. (Shanghai Institute of Ceramics, Academia Sinica (China))

1989-01-01

350

Object Extraction from High-Resolution Multisensor Image Data  

Microsoft Academic Search

An approach to the combined extraction of linear as well as areal objects from multisensor image data based on a feature- and object-level fusion is proposed. Data source s are high-resolution panchromatic digital orthoimages, multispectral image data, and interferometric SAR data. Rural test areas consisting of a road network, agricultural fields, and small villages were investigated. Road networks are extracted

Olaf Hellwich; Christian Wiedemann

2000-01-01

351

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

352

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

353

CM-SAF high-resolution radiation budget products  

Microsoft Academic Search

In this paper the system employed at the Royal Meteorological Institute of Belgium (RMIB) within the Climate Monitoring Satellite Application Facility (CM-SAF) for the production of Top Of the Atmosphere (TOA) radiation budget components is described. One of the goals of the CM-SAF is to provide consistent TOA and surface radiation budget components and cloud properties at high spatial resolution

Bogdan Nicula; Steven Dewitte; Nicolas Clerbaux

2003-01-01

354

A High Resolution Dynamic Technique of Thermoelectric Power Measurements  

Microsoft Academic Search

A new technique, principally applicable to metals and alloys, has been developed for high resolution absolute thermoelectric power (TEP) and differential thermoelectric power measurements. It utilizes two continuously monitoring dc nanovolt amplifiers, one for the sample couple thermoelectric voltage and the other for a thermocouple voltage proportional to temperature differences developed across the samples. The outputs of these amplifiers are

Donald R. Zrudsky; Alan B. Showalter

1973-01-01

355

High-resolution EUS in children with eosinophilic “allergic” esophagitis  

Microsoft Academic Search

Background: The pathophysiology of dysphagia associated with eosinophilic esophagitis is unknown. This study investigated possible anatomic alterations in children with eosinophilic esophagitis in comparison with healthy children by using high-resolution EUS to precisely measure individual tissue layers of the esophagus. Methods: Children with eosinophilic esophagitis (n = 11) and control children (n = 8) without esophagitis were prospectively evaluated by

Victor L. Fox; Samuel Nurko; Jonathan E. Teitelbaum; Kamran Badizadegan; Glenn T. Furuta

2003-01-01

356

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

357

Ultra high resolution soft x-ray tomography.  

National Technical Information Service (NTIS)

Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were se...

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

1995-01-01

358

High resolution electron–momentum resolved ion coincidence spectroscopy  

Microsoft Academic Search

When molecules are irradiated by x-rays complicated breakup reactions are initiated: inner shell excitation or ionization leads to a cascade of Auger decays resulting in multiple ionization and multiple bond breaks. During the last years high resolution electron - ion coincidence spectroscopy has developed into a standard tool to analyse molecular break-up reaction pathways. If ion pairs or the momenta

G Prümper; X J Liu; H Fukuzawa; K Ueda; V Carravetta; J Harries; Y Tamenori; S Nagaoka

2007-01-01

359

Improvement of sensitivity in high-resolution ERDA  

Microsoft Academic Search

Recently, we have developed a new detector system for a magnetic spectrometer to reduce the background noise in high-resolution Rutherford backscattering spectroscopy. The detector system consists of a MCP detector for ion detection, which has a thin Mylar foil in front of the detector, and an electron detector to detect secondary electrons emitted by the ions upon impact on the

H. Hashimoto; S. Fujita; K. Nakajima; M. Suzuki; K. Sasakawa; K. Kimura

360

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

361

Designing Arrays for Modern High-Resolution Methods.  

National Technical Information Service (NTIS)

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 th...

F. U. Dowla

1987-01-01

362

High-pass resolution perimetry: Central-field neuroretinal correlates  

Microsoft Academic Search

Minimum angles of resolution (MAR) were measured at 0–10 deg horizontal eccentricity in three normal subjects, using high-pass spatial frequency filtered targets, at four different contrast levels. Results were correlated with recent data on human cone and ganglion cell separations in corresponding retinal locations. MARs and cone separations showed a close proportionality through the origin for all contrast levels. Ganglion

Lars Frisén

1995-01-01

363

The accuracy of high resolution winds from QuikSCAT  

Microsoft Academic Search

The accuracy of the high resolution QuikSCAT wind product was quantified using spatially and temporally collocated 10 m equivalent neutral stability winds, calculated from selected NOAA NDBC buoy measurements. Only buoys that had sample correlation higher than 1.5 were used in this validation, a total of 5704 records. The validation followed the Freilich nonlinear statistical analysis approach. This analysis of

Zorana Jelenak; Laurence N. Connor; Paul S. Chang

2002-01-01

364

High-Resolution, Large-Area, Nano Imprint Lithography.  

National Technical Information Service (NTIS)

This document contains results from four different basic research projects under the Phase I of US-Korea NBIT Program (2007-2010). It is the 2nd year results covering research results from 2008-2009. It begins with the fourth report, 'High-resolution, Lar...

K. Kim, M. Jo S. Park, Y. Lee

2009-01-01

365

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

366

Wide swath, high resolution SAR using multiple receive apertures  

Microsoft Academic Search

When one attempts to image a large area while maintaining high resolution, ambiguities often appear. This occurs when the number of pixels exceeds the number of measurements or when the area includes range-Doppler ambiguities. In fact, the number of independent samples obtained by a single-receiver SAR, and consequently the number of pixels that can be unambiguously imaged, is equal to

Nathan Goodman; Devindran Rajakrishna; Jim Stiles

1999-01-01

367

High Resolution Imaging of Circumstellar Disks at Millimeter Wavelengths  

NASA Technical Reports Server (NTRS)

We update progress on our research program to use high angular resolution imaging of thermal dust continuum emission at millimeter and submillimeter wavelengths to probe the structure of protoplanetary disks and debris disks around nearby stars. Observations at these wavelengths are advantageous because the dust emission is generally optically thin and directly proportional to mass, contrast with stellar photospheres is not problematic, and the wavelength dependence provides information on an important regime of grain sizes. We employ several facilities for state-of-the-art high resolution observations, including the Very Large Array (VLA), the Australia Telescope Compact Array (ATCA), the Plateau de Bure Interferometer (PdBI) of the Institut de RadioAstronomie Millimetrique, the Submillimeter Array (SMA) of the Smithsonian Astrophysical Observatory, and the Caltech Submillimeter Observatory (CSO). Many recent highlights of our program were presented in an invited review on High Angular Resolution Studies of Disks- the Millimetre at IAU Symposium 221, Star Formation at High Angular Resolution, in July 2003.

Wilner, David J.

2003-01-01

368

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

369

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

370

High resolution X-ray spectroscopy of massive stars  

NASA Astrophysics Data System (ADS)

This thesis presents studies of high-resolution X-ray spectra of massive stars. Diffraction grating spectrometers onboard the XMM- Newton and Chandra satellite X-ray observatories have revolutionized our understanding of X-ray emission from massive stars, allowing the resolution of individual spectral lines and the study of their Doppler profiles. I discuss the use of line strengths and ratios to constrain temperature distributions, elemental abundances, and distribution of X-ray emitting plasma near a star. I also discuss the interpretation of Doppler profiles in light of their unexpected lack of asymmetry.

Leutenegger, Maurice Andrew

371

High resolution capacitance detection circuit for rotor micro-gyroscope  

NASA Astrophysics Data System (ADS)

Conventional methods for rotor position detection of micro-gyroscopes include common exciting electrodes (single frequency) and common sensing electrodes (frequency multiplex), but they have encountered some problems. So we present a high resolution and low noise pick-off circuit for micro-gyroscopes which utilizes the time multiplex method. The detecting circuit adopts a continuous-time current sensing circuit for capacitance measurement, and its noise analysis of the charge amplifier is introduced. The equivalent output noise power spectral density of phase-sensitive demodulation is 120 nV/Hz1/2. Tests revealed that the whole circuitry has a relative capacitance resolution of 1 × 10-8.

Ren, Ming-Yuan; Zhang, Hai-Feng; Liu, Xiao-Wei; Mao, Zhi-Gang

2014-03-01

372

A High-resolution Reanalysis for the European CORDEX Region  

NASA Astrophysics Data System (ADS)

A High-resolution Reanalysis for the European CORDEX Region Within the Hans-Ertel-Centre for Weather Research (HErZ), the climate monitoring branch concentrates efforts on the assessment and analysis of regional climate in Germany and Europe. In joint cooperation with DWD (German Meteorological Service), a high-resolution reanalysis system based on the COSMO model has been developed. Reanalyses gain more and more importance as a source of meteorological information for many purposes and applications. Several global reanalyses projects (e.g., ERA, MERRA, CSFR, JMA9) produce and verify these data sets to provide time series as long as possible combined with a high data quality. Due to a spatial resolution down to 50-70km and 3-hourly temporal output, they are not suitable for small scale problems (e.g., regional climate assessment, meso-scale NWP verification, input for subsequent models such as river runoff simulations). The implementation of regional reanalyses based on a limited area model along with a data assimilation scheme is able to generate reanalysis data sets with high spatio-temporal resolution. The work presented here focuses on the regional reanalysis for Europe with a domain matching the CORDEX-EURO-11 specifications, albeit at a higher spatial resolution, i.e., 0.055° (6km) instead of 0.11° (12km). The COSMO reanalysis system comprises the assimilation of observational data using the existing nudging scheme of COSMO and is complemented by a special soil moisture analysis and boundary conditions given by ERA-interim data. The reanalysis data set currently covers 6 years (2007-2012). The evaluation of the reanalyses is done using independent observations with special emphasis on precipitation and high-impact weather situations. The development and evaluation of the COSMO-based reanalysis for the CORDEX-Euro domain can be seen as a preparation for joint European activities on the development of an ensemble system of regional reanalyses for Europe.

Bentzien, Sabrina; Bollmeyer, Christoph; Crewell, Susanne; Friederichs, Petra; Hense, Andreas; Keller, Jan; Keune, Jessica; Kneifel, Stefan; Ohlwein, Christian; Pscheidt, Ieda; Redl, Stephanie; Steinke, Sandra

2014-05-01

373

High-resolution observations of rainfall: Potential for scaling studies  

NASA Astrophysics Data System (ADS)

Delft University has developed a new scanning Doppler-polarimetric radar with the particular aim to enable observations at high spatial resolution (a minimum of 3 meter) and high sensitivity. The radar is located on the top of 200 meter high meteorological observation tower at CESAR Observatory. The radar is capable of measuring fog, drizzle and heavier rain. Approximately 50 days per year the radar is located inside low-level water clouds, which enables interesting measurements of the horizontal structures of such clouds. With its high resolution new observational studies of the scaling properties of rainfall structures become possible. The presentation will discuss the radar capabilities and its application to the study of rainfall structures.

Ventura Figueras, J.; Russchenberg, H.

2009-04-01

374

Scalable, flexible and high resolution patterning of CVD graphene.  

PubMed

The unique properties of graphene make it a promising material for interconnects in flexible and transparent electronics. To increase the commercial impact of graphene in those applications, a scalable and economical method for producing graphene patterns is required. The direct synthesis of graphene from an area-selectively passivated catalyst substrate can generate patterned graphene of high quality. We here present a solution-based method for producing patterned passivation layers. Various deposition methods such as ink-jet deposition and microcontact printing were explored, that can satisfy application demands for low cost, high resolution and scalable production of patterned graphene. The demonstrated high quality and nanometer precision of grown graphene establishes the potential of this synthesis approach for future commercial applications of graphene. Finally, the ability to transfer high resolution graphene patterns onto complex three-dimensional surfaces affords the vision of graphene-based interconnects in novel electronics. PMID:24189709

Hofmann, Mario; Hsieh, Ya-Ping; Hsu, Allen L; Kong, Jing

2014-01-01

375

High resolution imaging with multilayer telescopes: resolution performance of the MSSTA II telescopes  

SciTech Connect

The Multi-Spectral Solar Telescope Array (MSSTA) is a sounding rocket-borne observatory composed of a set of normal-incidence multilayer-coated telescopes that obtained selected bandpass spectroheliograms (44 to 1550 Aa) of the solar atmosphere. These spectroheliograms were recorded on specially fabricated XUV and FUV 70-mm Kodak film. Rocket launches of this instrument payload took place in 1991 (MSSTA I) and 1994 (MSSTA II) at the White Sands Missile Test Range in New Mexico, sponsored by the National Aeronautics and Space Administration (NASA) sounding rocket experiment program. Immediately prior to the 1994 launch, visible light focusing tests of each telescope were performed in situ using a 1951 standard Air Force high-resolution test target, to measure optical resolution performance. We determined that the MSSTA II telescopes performed at diffraction-limited resolutions down to 0.70 arcsec at visible wavelengths. Based on these measurements, we calculate an upper bound to the focusing errors that incorporate the sum of all uncorrelated system focus errors that affect resolution performance. Coupling these upper bound estimates with the in-band diffraction limits, surface scattering errors and payload pointing jitter, we demonstrate that 11 of 19 MSSTA II telescopes--having negligible figures of focus errors in comparison to the corresponding visible diffraction limits--performed at sub arcsecond resolution at their operational FUV/EUV/XUV wavelengths during flight. We estimate the in-band performance down to 0.14{+-}0.08 arcsec. (c) 2000 Society of Photo-Optical Instrumentation Engineers.

Martinez-Galarce, Dennis S. [Stanford University, W. W. Hansen Experimental Physics Laboratory, Electrical Engineering Department, Stanford, California 94305-4060 (United States)] [Stanford University, W. W. Hansen Experimental Physics Laboratory, Electrical Engineering Department, Stanford, California 94305-4060 (United States); Walker, Arthur B. C. II [Stanford University, Department of Physics, Department of Applied Physics, Stanford, California 94305-4060 (United States); Gore, David B. [University of Alabama, Department of Physics, Birmingham, Alabama 35294-1170 (United States)] [University of Alabama, Department of Physics, Birmingham, Alabama 35294-1170 (United States); Kankelborg, Charles C. [Montana State University, Department of Physics, Bozeman, Montana (United States)] [Montana State University, Department of Physics, Bozeman, Montana (United States); Hoover, Richard B. [NASA-Marshall Space Flight Center, Space Science Laboratory, ES-52, Huntsville, Alabama 35812 (United States)] [NASA-Marshall Space Flight Center, Space Science Laboratory, ES-52, Huntsville, Alabama 35812 (United States); Barbee, T. W. Jr. [Lawrence Livermore National Lab, P.O. Box 808, Livermore, California 94550 (United States)] [Lawrence Livermore National Lab, P.O. Box 808, Livermore, California 94550 (United States); Boerner, P. F. X. [Stanford University, Department of Physics, Stanford, California 94305-4060 (United States)] [Stanford University, Department of Physics, Stanford, California 94305-4060 (United States)

2000-04-01

376

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

377

Colorado High-resolution Echelle Stellar Spectrograph (CHESS)  

NASA Astrophysics Data System (ADS)

We discuss the design of a new high-efficiency, high-resolution far ultraviolet echelle spectrograph. Our project concentrates on utilizing new technologies for gratings and detectors to reduce the impact of scattered light and maximize quantum efficiency over a large bandpass. This program will enable advances in a vast number of astrophysical subjects. Topics ranging from protoplanetary disks to the intergalactic medium can be addressed by incorporating such a spectrograph into a future, long-duration mission.

Beasley, Matthew; Burgh, Eric; France, Kevin

2010-07-01

378

WINERED: a warm near-infrared high-resolution spectrograph  

Microsoft Academic Search

We are developing a new near-infrared high-resolution (Rmax = 100,000) and high-sensitive spectrograph WINERED, which is specifically customized for short NIR bands at 0.9-1.35 mum. WINERED employs the following two novel approaches in the optical system: (1) portable design with a ZnSe immersion grating and (2) warm optics without any cold stops. These concepts result in several essential advantages as

Yuji Ikeda; Naoto Kobayashi; Sohei Kondo; Chikako Yasui; Kentaro Motohara; Atsushi Minami

2006-01-01

379

WINKLER - An imaging high resolution gamma-ray spectrometer  

Microsoft Academic Search

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

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

1991-01-01

380

WINKLER: An imaging high resolution gamma-ray spectrometer  

Microsoft Academic Search

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

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

1991-01-01

381

Scalable, flexible and high resolution patterning of CVD graphene  

NASA Astrophysics Data System (ADS)

The unique properties of graphene make it a promising material for interconnects in flexible and transparent electronics. To increase the commercial impact of graphene in those applications, a scalable and economical method for producing graphene patterns is required. The direct synthesis of graphene from an area-selectively passivated catalyst substrate can generate patterned graphene of high quality. We here present a solution-based method for producing patterned passivation layers. Various deposition methods such as ink-jet deposition and microcontact printing were explored, that can satisfy application demands for low cost, high resolution and scalable production of patterned graphene. The demonstrated high quality and nanometer precision of grown graphene establishes the potential of this synthesis approach for future commercial applications of graphene. Finally, the ability to transfer high resolution graphene patterns onto complex three-dimensional surfaces affords the vision of graphene-based interconnects in novel electronics.The unique properties of graphene make it a promising material for interconnects in flexible and transparent electronics. To increase the commercial impact of graphene in those applications, a scalable and economical method for producing graphene patterns is required. The direct synthesis of graphene from an area-selectively passivated catalyst substrate can generate patterned graphene of high quality. We here present a solution-based method for producing patterned passivation layers. Various deposition methods such as ink-jet deposition and microcontact printing were explored, that can satisfy application demands for low cost, high resolution and scalable production of patterned graphene. The demonstrated high quality and nanometer precision of grown graphene establishes the potential of this synthesis approach for future commercial applications of graphene. Finally, the ability to transfer high resolution graphene patterns onto complex three-dimensional surfaces affords the vision of graphene-based interconnects in novel electronics. Electronic supplementary information (ESI) available: Detailed materials characterization and experimental procedures. See DOI: 10.1039/c3nr04968j

Hofmann, Mario; Hsieh, Ya-Ping; Hsu, Allen L.; Kong, Jing

2013-12-01

382

High-resolution von Hamos crystal X-ray spectrometer  

NASA Astrophysics Data System (ADS)

A high-resolution von Hamos Bragg crystal X-ray spectrometer is described. The instrument was designed for the study of X-ray emission from low- Z elements and L X-ray spectra of medium to high Z targets induced by photon and particle impact. The construction details and operational characteristics of the spectrometer are presented along with the data illustrating the utility of this facility in different areas of research in atomic physics.

Hoszowska, J.; Dousse, J.-Cl.; Kern, J.; Rhême, Ch.

1996-02-01

383

High-resolution von Hamos crystal X-ray spectrometer  

Microsoft Academic Search

A high-resolution von Hamos Bragg crystal X-ray spectrometer is described. The instrument was designed for the study of X-ray emission from low-Z elements and L X-ray spectra of medium to high Z targets induced by photon and particle impact. The construction details and operational characteristics of the spectrometer are presented along with the data illustrating the utility of this facility

J. Hoszowska; J.-Cl. Dousse; J. Kern; Ch. Rhême

1996-01-01

384

Preliminary optical design of ARIES-High Resolution Echelle Spectrograph  

NASA Astrophysics Data System (ADS)

For the upcoming 3.6m telescope a High Resolution Echelle Spectrograph is being envisaged as the key instrument to meet wide range science goals namely, asteroseismology, exoplanet search, doppler imaging of spotted stars, massive stars, colliding wind binaries and abundance studies etc. These objectives, in turn, result in a series of technical requirements e.g. spectral coverage of 300 nm to 900 nm, spectral resolution ˜60,000, radial velocity stability < 20 ms^{-1} etc. In addition, a temperature controlled environment and flexible but robust operation is also required. The preliminary optical design of the ARIES-High Resolution Echelle Spectrograph (ARIES-HIRES) is based on the white pupil concept. It is a fiber fed spectrograph, which converts F/9 beam from the telescope to F/3.6. An image slicer would be used to slice the image of the fiber exit to achieve high spectral resolution. The use of intermediate folding mirror makes the instrument more compact. Prisms have been used as cross dispersers to achieve more uniform inter order separation. Simultaneous wavelength spectrum would be used to correct the instrument drift. The spectrograph will be mounted on the vibration isolation table kept inside the telescope pier in an isolated environment. The acquisition and guiding unit, atmospheric dispersion corrector, and calibration unit will be part of the instrument.

Pant, Jayshreekar; Pandey, J. C.; Sagar, Ram

385

High-Resolution Angioscopic Imaging During Endovascular Neurosurgery  

PubMed Central

BACKGROUND: Endoluminal optical imaging, or angioscopy, has not seen widespread application during neurointerventional procedures, largely as a result of the poor imaging resolution of existing angioscopes. Scanning fiber endoscopes (SFEs) are a novel endoscopic platform that allows high-resolution video imaging in an ultraminiature form factor that is compatible with currently used distal access endoluminal catheters. OBJECTIVE: To test the feasibility and potential utility of high-resolution angioscopy with an SFE during common endovascular neurosurgical procedures. METHODS: A 3.7-French SFE was used in a porcine model system to image endothelial disruption, ischemic stroke and mechanical thrombectomy, aneurysm coiling, and flow-diverting stent placement. RESULTS: High-resolution, video-rate imaging was shown to be possible during all of the common procedures tested and provided information that was complementary to standard fluoroscopic imaging. SFE angioscopy was able to assess novel factors such as aneurysm base coverage fraction and side branch patency, which have previously not been possible to determine with conventional angiography. CONCLUSION: Endovascular imaging with an SFE provides important information on factors that cannot be assessed fluoroscopically and is a novel platform on which future neurointerventional techniques may be based because it allows for periprocedural inspection of the integrity of the vascular system and the deployed devices. In addition, it may be of diagnostic use for inspecting the vascular wall and postprocedure device evaluation. ABBREVIATIONS: CFB, coherent fiber bundle F, French SFE, scanning fiber endoscope

McVeigh, Patrick Z.; Sacho, Raphael; Weersink, Robert A.; Pereira, Vitor M.; Kucharczyk, Walter; Seibel, Eric J.; Wilson, Brian C.

2014-01-01

386

High-resolution Imaging Techniques for the Assessment of Osteoporosis  

PubMed Central

Synopsis The importance of assessing the bone’s 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 bone’s 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.

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

2010-01-01

387

Advances toward high spectral resolution quantum X-ray calorimetry  

NASA Technical Reports Server (NTRS)

Thermal detectors for X-ray spectroscopy combining high spectral resolution and quantum efficiency have been developed. These microcalorimeters measure the energy released in the absorption of a single photon by sensing the rise in temperature of a small absorbing structure. The ultimate energy resolution of such a device is limited by the thermodynamic power fluctuations in the thermal link between the calorimeter and isothermal bath and can in principle be made as low as 1 eV. The performance of a real device is degraded due to noise contributions such as excess 1/f noise in the thermistor and incomplete conversion of energy into phonons. The authors report some recent advances in thermometry, X-ray absorption and thermalization, fabrication techniques, and detector optimization in the presence of noise. These improvements have resulted in a device with a spectral resolution of 17 eV FWHM, measured at 6 keV.

Moseley, S. H.; Kelley, R. L.; Schoelkopf, R. J.; Szymkowiak, A. E.; Mccammon, D.

1988-01-01

388

Broadband high resolution X-ray spectral analyzer  

DOEpatents

A broad bandwidth high resolution x-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces x-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available x-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for x-ray microanalysis or in research applications such as laboratory and astrophysical x-ray and particle spectroscopy.

Silver, Eric H. (Berkeley, CA); Legros, Mark (Berkeley, CA); Madden, Norm W. (Livermore, CA); Goulding, Fred (Lafayette, CA); Landis, Don (Pinole, CA)

1998-01-01

389

Tuning and scanning control system for high resolution alexandrite lasers  

NASA Technical Reports Server (NTRS)

An alexandrite laser is spectrally narrowed and tuned by the use of three optical elements. Each element provides a successively higher degree of spectral resolution. The digitally controlled tuning and scanning control servo system simultaneously positions all three optical elements to provide continuous high resolution laser spectral tuning. The user may select manual, single, or continuous modes of automated scanning of ranges up to 3.00/cm and at scan rates up to 3.85/cm/min. Scanning over an extended range of up to 9.999/cm may be achieved if the highest resolution optic is removed from the system. The control system is also capable of being remotely operated by another computer or controller via standard RS-232 serial data link.

Smith, James C.; Schwemmer, Geary K.

1988-01-01

390

High-resolution surface photometry of elliptical galaxies  

NASA Technical Reports Server (NTRS)

High-resolution CCD surface photometry profiles have been obtained for a sample of 42 nearby elliptical and SO galaxies as a first step in a program to investigate their central structure and core properties. A comparison of the present profiles to those of other observers shows that the accuracy of the central surface brightnesses is to better than 0.02 mag rms. Central resolution is limited by the atmospheric seeing PSF which is measured for each profile. A hybrid Fourier deconvolution procedure has been developed to correct the surface photometry for seeing in a model-independent way. Tests of the procedure on simulated galaxy images show that intrinsic core radii equal to the seeing FWHM or larger can be recovered from the observations. Application of the deconvolution procedure to the observed galaxies yields surface photometry profiles of slightly sub-arc second resolution.

Lauer, T. R.

1985-01-01

391

Broadband high resolution X-ray spectral analyzer  

DOEpatents

A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

1998-07-07

392

Ultra high resolution soft x-ray tomography  

SciTech Connect

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

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

1995-07-19

393

Cortical Surface Reconstruction from High-Resolution MR Brain Images  

PubMed Central

Reconstruction of the cerebral cortex from magnetic resonance (MR) images is an important step in quantitative analysis of the human brain structure, for example, in sulcal morphometry and in studies of cortical thickness. Existing cortical reconstruction approaches are typically optimized for standard resolution (~1?mm) data and are not directly applicable to higher resolution images. A new PDE-based method is presented for the automated cortical reconstruction that is computationally efficient and scales well with grid resolution, and thus is particularly suitable for high-resolution MR images with submillimeter voxel size. The method uses a mathematical model of a field in an inhomogeneous dielectric. This field mapping, similarly to a Laplacian mapping, has nice laminar properties in the cortical layer, and helps to identify the unresolved boundaries between cortical banks in narrow sulci. The pial cortical surface is reconstructed by advection along the field gradient as a geometric deformable model constrained by topology-preserving level set approach. The method's performance is illustrated on exvivo images with 0.25–0.35?mm isotropic voxels. The method is further evaluated by cross-comparison with results of the FreeSurfer software on standard resolution data sets from the OASIS database featuring pairs of repeated scans for 20 healthy young subjects.

Osechinskiy, Sergey; Kruggel, Frithjof

2012-01-01

394

Characterization of high-resolution HafSOx inorganic resists  

NASA Astrophysics Data System (ADS)

Inorganic resists are of considerable interest for advanced lithography at the nanoscale due to the potential for high resolution, low line width roughness (LWR), and high sensitivity. Historically inorganic resists suffered from low sensitivity, however approaches have been identified to increase sensitivity while maintaining high contrast. An aqueous precursor of Hf(OH)4-2x-2y(O2)x(SO4)y·qH2O (HafSOx) has been demonstrated with excellent sensitivity to EUV and electrons, while still obtaining high resolution and low LWR. In this work, we characterize both HafSOx precursor solutions and spin-coated thin films using high-resolution transmission electron microscopy (HR-TEM) with energy-dispersive X-ray spectroscopy (EDS) elemental analysis. HR-TEM of precursor solutions drop cast onto TEM grids confirmed the presence of nanoscale particles. HR-TEM cross sectional images showed that spin-coated HafSOx films are initially uniform in appearance and composition for thin (12 nm) films, however thicker (30 nm) films display segregation of species leading to multilayer structures. Regardless of film thickness, extended exposure to the high energy TEM electron beam induces significant migration of oxygen species to the Si interface. These species result in the formation of SiOx layers that increase in thickness with an increase in TEM electron beam dose. Sulfate is also very mobile in the films and likely assists in the significant condensation exhibited in completely processed films.

Oleksak, R. P.; Herman, G. S.

2014-04-01

395

High Resolution Topography for Thermal Modeling on Vesta  

NASA Astrophysics Data System (ADS)

For more than a year, NASA's Dawn mission has been providing fascinating data on Vesta. Surface temperatures and thermal parameters are being derived using measurements by the Visual and Infrared Spectrometer (VIR) (Capria et al., 2012). However, the spatial distribution of temperatures is complex due to significant albedo variations over short distance scales and extensive cratering that generates shadows and complex surface features over small spatial scales. This results in VIR pixels that have sub-pixel variations in the temperature that are difficult to deconvolve. Here we report the benefits of using high-resolution topographic modeling when interpreting the thermal component of the VIR observations. Stereo-photoclinometry has been used for years to derive accurate shape models of planetary surfaces. It uses high-resolution images to determine both the surface reflectance and the incidence and emission angles for every pixel of every image. Using this data, we construct both the local surface topography (known as maplets) as well as reflectance values for the Cornelia crater on Vesta (-9.7 Lat, 225 Lon), a fresh crater that has sharp relief and significant variations in albedo. Using this terrain model, we construct high-resolution, time-resolved insolation maps accounting for Bond albedo, incidence angle and shadowing effects of near-by features. From these maps, we calculate the temperature of the surface and subsurface using a 1-D thermal conduction model. This time-resolved model allows us to calculate the temperature at 3 times the spatial resolution for all regions of Cornelia crater at the time when VIR collected its observations. By combining the thermal flux for all the high-resolution points within a single VIR pixel element, we generate a thermal spectrum that accurately models the VIR data because they reflect slope inflections that are generated by sub-pixel temperature variations.

Palmer, Eric; Sykes, M. V.; Gaskell, R. W.; Li, J.

2012-10-01

396

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.

Huang, Sheng-Wen; Hou, Yang; Ashkenazi, Shai; O'Donnell, Matthew

2008-01-01

397

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

398

High-resolution dynamical modelling of the Antarctic stratospheric vortex  

NASA Technical Reports Server (NTRS)

Progress is reported on the high-resolution three-dimensional numerical simulation of flows characteristic of the Antarctic wintertime stratosphere. The numerical model is a modified version of the Reading University sigma-coordinate used previously for tropospheric studies. Physical parameterizations are kept to a minimum in order to concentrate as much computing power as possible on simulating details of the dynamical processes. The major question addressed is whether the features observed in recent high-resolution two-dimensional simulations - namely: (1) the formation of a sharp edge to the vortex (seen in the potential vorticity field), (2) the survival of the polar vortex in a material entity, and (3) the formation of small-scale eddies rough the break-up of tongues of high potential vorticity drawn out from the polar vortex - are realized in three-dimensional simulations.

Haynes, P. H.

1988-01-01

399

High-resolution 3D coherent laser radar imaging  

NASA Astrophysics Data System (ADS)

The Super-resolution Sensor System (S3) program is an ambitious effort to exploit the maximum information a laser-based sensor can obtain. At Lockheed Martin Coherent Technologies (LMCT), we are developing methods of incorporating multi-function operation (3D imaging, vibrometry, polarimetry, aperture synthesis, etc.) into a single device. The waveforms will be matched to the requirements of both hardware (e.g., optical amplifiers, modulators) and the targets being imaged. The first successful demonstrations of this program have produced high-resolution, three-dimensional images at intermediate stand-off ranges. In addition, heavy camouflage penetration has been successfully demonstrated. The resolution of a ladar sensor scales with the bandwidth as dR = c/(2B), with a corresponding scaling of the range precision. Therefore, the ability to achieve large bandwidths is crucial to developing a high-resolution sensor. While there are many methods of achieving the benefit of large bandwidths while using lower bandwidth electronics (e.g., an FMCW implementation), the S3 system produces and detects the full waveform bandwidth, enabling a large set of adaptive waveforms for applications requiring large range search intervals (RSI) and short duration waveforms. This paper highlights the three-dimensional imaging and camo penetration.

Buck, Joseph; Malm, Andrew; Zakel, Andrew; Krause, Brian; Tiemann, Bruce

2007-05-01

400

Embedded registration system for high-resolution Neutron Monitor data  

NASA Astrophysics Data System (ADS)

In the frame of NMDB, the real-time database for high-resolution Neutron Monitor measure-ments, a new registration system for Neutron Monitors has been developed. This embedded system allows to record high-resolution data with typically 1 minute resolution, but is capable to deliver periodic data with a resolution down to a few seconds. It processes the data in real-time and is designed to record data from up to 18 Neutron Monitor tubes, but is easily expandable to 24 or 36 tube configurations. The data is acquired along with the atmospheric pressure, and precisely time-tagged using a GPS clock or the Network Time Protocol. Data is then stored in an embedded relational database and synchronized with an external relational database from where data is further processed and then submitted to NMDB. This cost-effective registration system is an alternative approach to PC based registration systems allowing new and existing Neutron Monitor stations to easily upgrade their station to be fully compatible with the NMDB requirements.

Steigies, Christian; Garcia, Oscar

401

High-resolution teleradiology applications within the hospital  

NASA Astrophysics Data System (ADS)

Many of the commercial applications for teleradiology have involved the transmission of reduced resolution x-ray images over modest bandwidth telecommunications lines for the purpose of making a preliminary diagnosis. In order to study the technical and operational requirements for future teleradiology applications, the authors have focused on the demanding requirements for teleradiology within the hospital and medical center. Applications within the hospital often require x-ray images of primary diagnostic quality transmitted with a minimum of delay. An experimental, high-resolution film scan/print system designed by Health Sciences Division, Eastman Kodak Company, has been developed for installation in a working clinical environment. Images scanned at a spatial resolution of 4K X 5K can be delivered over a fiber optic link to a laser film printer at a rate of two films per minute. Preliminary plans to install this device in a variety of clinical settings have led to rethinking the requirements for automatic film loading, film and patient identification, throughput requirements, and image display formats. As an initial implementation, and application is being developed which allows chest radiographs taken in the admission area to be interpreted at a remote site within the hospital. Images can be viewed on high resolution monitors, or film replicates can be produced on a nearby laser printer. Tight coupling with a radiology information system provides access to relevant diagnostic information including prior radiology reports, and prompt electronic reporting and signature can be accomplished.

Jost, R. Gilbert; Blaine, G. James; Kocher, Thomas E.; Muka, Edward; Whiting, Bruce R.

1991-07-01

402

Dynamics of Solar Fine Structure: Observation with High Spatial Resolution  

NASA Astrophysics Data System (ADS)

The Sun is an ideal object for studying non-magnetic and magnetic processes in cool stars. Here, we focus on fine structures of a few 100 km in the solar atmosphere. Granular overshoot, motions and waves of magnetic elements in the quiet Sun and in plages, etc., all affect the atmospheric structure from the bottom of the photosphere up to the corona and the solar wind. Observations with high spatial resolution are required to reveal the dynamic behaviour and to understand the underlying physical processes. During the past five years, speckle methods have become an excellent tool to obtain images of solar fine structure with diffraction-limited resolution. We demonstrate by some examples how one can gain new insights from speckle interferometry. Likewise, spectroscopy of solar fine structure is also making rapid progress towards high spatial resolution. Our two-dimensional, narrow-band spectrometer (Delta\\lambda = 20-30 mAA ), working with a scanning Fabry-Perot interferometer, proves very powerful in several aspects. We present some results obtained in Na D_2 from the quiet solar chromosphere. Using suitable observing techniques together with image restoration, we aim at achieving diffraction-limited resolution also for narrow-band spectroscopy.

Al, N.; Bendlin, C.; de Boer, C. R.; Denker, C.; Kneer, F.; Schmitt, D.; Volkmer, R.; Wilken, V.

403

High resolution imaging with differential infrared absorption micro-spectroscopy.  

PubMed

Although confocal infrared (IR) absorption micro-spectroscopy is well established for far-field chemical imaging, its scope remains restricted since diffraction limits the spatial resolution to values a little above half the radiation wavelength. Yet, the successful implementations of below-the-diffraction limit far-field fluorescence microscopies using saturated irradiation patterns for example for stimulated-emission depletion and saturated structured-illumination suggest the possibility of using a similar optical patterning strategy for infrared absorption mapping at high resolution. Simulations are used to show that the simple mapping of the difference in transmitted/reflected IR energy between a saturated vortex-shaped beam and a Gaussian reference with a confocal microscope affords the generation of high-resolution vibrational absorption images. On the basis of experimentally relevant parameters, the simulations of the differential absorption scheme reveal a spatial resolution better than a tenth of the wavelength for incident energies about a decade above the saturation threshold. The saturated structured illumination concepts are thus expected to be compatible with the establishment of point-like point-spread functions for measuring the absorbance of samples with a scanning confocal microscope recording the differential transmission/reflection. PMID:24216788

Pita, Isabel; Hendaoui, Nordine; Liu, Ning; Kumbham, Mahendar; Tofail, Syed A M; Peremans, André; Silien, Christophe

2013-11-01

404

High-resolution electron microscopy of advanced materials  

SciTech Connect

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

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

1997-11-01

405

Temporal analysis of all high-resolution Mars imaging products  

NASA Astrophysics Data System (ADS)

A meta-data analysis has been performed of high-resolution imagery that have been acquired over the last four decades from Mars. More specifically, we are interested in two independent image parameters, the time that each image was acquired and the spatial resolution with which the planetary region is mapped in the image. We are only interested in mapping changes in high-resolution images. We use two different upper thresholds to discriminate them from low-resolution images, twenty metres and a hundred metres per pixel. In order to be able to extract semantic information about the temporal and spatial distribution of high-resolution Martian imagery we adopt two grouping strategies. In the first, images are clustered according to the time period (counted in Martian Years) that they were acquired, so as to examine whether sporadic Martian phenomena can be identified (e.g. a new crater) from imagery that depict the same area in different time periods. In the second grouping, images are clustered according to the Martian season that they were acquired, so as to examine whether seasonal Martian phenomena can be identified from imagery that depict the same area during the same season. This analysis supports the hypothesis that there is sufficient coverage for both tasks, since the Martian surface has been mapped at least once in each epoch and more than twice since 2002 and for each season at least 10 % of Martian surface has been mapped at least three times. The resulting maps and graphical plots will be presented will provide additional detail to this report.

Sidiropoulos, P.; Muller, J.-P.

2014-04-01

406

Mixing length controls on high resolution simulations of convective storms  

NASA Astrophysics Data System (ADS)

Convective storms are a crucially important forecasting problem in the UK, not least because of the flooding they can cause. In the last few years many operational weather centres have begun to run at "convection permitting" resolutions, with the UK Met Office currently running a 1.5 km forecast model. While there is evidence that precipitation forecasts at this resolution are more accurate than lower resolution forecasts, it is clear that there are still significant shortcomings in the nature of the simulated convective cells at this resolution. Cells in the model tend to be too large and too intense, and tend not to organise into mesoscale complexes as observed, illustrating our lack of understanding of the nature of small-scale mixing and microphysical processes. The DYMECS (Dynamical and Microphysical Evolution of Convective Storms) project has obtained a large database of convective storm lifecycles by tracking storms with the Chilbolton Advanced Meteorological Radar. Individual storms were tracked on 40 days using a combination of scanning techniques to extract the dynamical and microphysical properties of the storm (such as storm size, vertical velocity, maximum surface rain-rate and hail intensity). In this study we perform simulations of some of the DYMECS cases with the Met Office Unified Model (UM) at horizontal grid lengths ranging from 1.5 km to 200 m, which allows us to apply a statistical approach to evaluate the properties and evolution of the simulated storms over a range of conditions. Here we present results comparing the storm morphology in the model and reality which show that the simulated storms become smaller as resolution increases and that the resolution that fits the observations best changes with the size of the observed cells. We investigate the sensitivity of storm morphology in the model to the mixing length used in the subgrid Smagorinsky mixing scheme. As the subgrid mixing length is decreased, the number of small storms with high area-averaged rain rates increases.

Hanley, Kirsty; Plant, Bob; Lean, Humphrey; Halliwell, Carol; Stein, Thorwald; Hogan, Robin

2013-04-01

407

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

408

Adaptive optics with pupil tracking for high resolution retinal imaging  

PubMed Central

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.

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

2012-01-01

409

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

410

MISTIGRI instrumental concept for high-resolution thermal infrared imaging  

NASA Astrophysics Data System (ADS)

High resolution images in the Thermal infrared provide a way to detect irrigated fields, to measure evapo-transpiration and detect plant water stress. Models and algorithms have largely improved to yield very good results. However the only in-orbit satellites providing high resolution images in the thermal infrared domain (Landsat, Aster) are long beyond their design lifetime. Furthermore, they do not provide frequent acquisitions (1 image every 16 days for Landsat and Aster, while 1 image per couple of days would be required to monitor plant water stress). There is indeed a need for high resolution and high repetitivity thermal infrared data for hydrological applications. CNES carried out a feasibility study of such a mission on a microsatellite. The mission is called MISTIGRI (MicroSatellite for Thermal InfraRed Ground Surface Imaging). The preliminary payload design was performed by Thales Alenia Space for CNES. An instrumental concept was proposed which fulfils the mission requirements. The study addressed both cooled and uncooled solutions, although a micro-bolometer detector was preferred after trade-off. This paper addresses the results of the MISTIGRI payload feasibility study; it presents the mission requirements, the proposed instrumental concept, describes the major subsystems and provides the preliminary performance budgets.

Tintó Garcia-Moreno, F.; Fargant, G.; Guerin, F.; Israbian, C.; Mathieu, J. C.; Michaud, J.; Bardoux, A.; Hagolle, O.; Lagouarde, J. P.

2009-08-01

411

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

412

High range resolution laser scanner with full waveform recording  

NASA Astrophysics Data System (ADS)

This paper describes the development of a high resolution waveform recording laser scanner and presents results obtained with the system. When collecting 3-D data on small objects, high range and transverse resolution is needed. In particular, if the objects are partly occluded by sparse materials such as vegetation, multiple returns from a single laser pulse may limit the image quality. The ability to resolve multiple echoes depends mainly on the laser pulse width and the receiver bandwidth. With the purpose to achieve high range resolution for multiple returns, we have developed a high performance 3-D LIDAR, called HiPer, with a short pulse fibre laser (500 ps), fast detectors (70 ps rise time) and a 20 GS/s oscilloscope for fast sampling. HiPer can acquire the full waveform, which can be used for off-line processing. This paper will describe the LIDAR system and present some image examples. The signal processing will also be described, with some examples from the off-line processing and the benefit of using the complete waveform.

Letalick, Dietmar; Larsson, Håkan; Tolt, Gustav; Allard, Lars; Wollner, Erika; Berglund, Folke

2010-10-01

413

The Astrophysical Plasmadynamic Explorer (APEX): A High Resolution Spectroscopic Observatory  

NASA Astrophysics Data System (ADS)

The dynamics and structure of stellar atmospheres and coronae are complex and strongly bound to the life cycle of stars, from their birth and descent to the main sequence, to their final stages in which the interstellar medium is enriched and stars proceed along various paths to a cooling compact object. Now EUVE, Chandra, and XMM-Newton have moved astronomical spectroscopy into the soft X-ray and EUV wavebands, where hot (105-108 K) plasmas radiate most strongly. High-resolution spectroscopy allows the identification of weak emission lines, the measurement of Doppler shifts and line profiles, and the detection of narrow absorption features. We present a mission concept for APEX (Astrophysical Plasmadynamic Explorer), a SMEX-class instrument that employs multilayer-grating spectrometers to achieve both high effective area and high spectral resolution at ultra-soft X-ray and EUV wavelengths. A prototype instrument has already been built and flown successfully on a sounding rocket. A high-resolution spectrum of the white dwarf G191-B2B was obtained.

Wood, Kent; Cruddace, Raymond; Kowalski, Michael; Yentis, Daryl; Gursky Barbee, Herb, Jr.; Goldstein, William; Kordas, Joseph; Fritz, Gilbert; Barstow, Martin; Bannister, Nigel; Lapington, John

2002-04-01

414

High-resolution 3D digital models of artworks  

NASA Astrophysics Data System (ADS)

The measurement of the shape of an artwork usually requires a high-resolution instrumentation, in order to catch small details such as chisel marks, sculptural relieves, surface cracks, etc. 3D scanning techniques, together with new modeling software tools, allow a high fidelity reproduction of an artwork: these can be applied either to support and document its repair or for the realization of 3D archives and virtual museums. Starting from a high-resolution digital model of an object, a further step could be its reproduction by means of fast-prototyping techniques like stereo-lithography or electro-erosion. This work is aimed at showing the performance of a high-resolution laser scanner devoted to Cultural Heritage applications. The device is portable and very versatile, in order to allow in situ applications, accurate and reliable, so to capture intricate details. This laser profilometer has been used in a few surveys, the most significant of which are the monitoring the various phases of the restoration process of an ellenistic bronze (the Minerva of Arezzo, Florence), the cataloguing of some archaeological findings (from the Grotta della Poesia, Lecce) and the documenting of wooden panels surface conditions (the "Madonna del Cardellino" by Raffaello and "La Tebaide" by Beato Angelico).

Fontana, Raffaella; Gambino, Maria Chiara; Greco, Marinella; Pampaloni, Enrico; Pezzati, Luca; Scopigno, Roberto

2003-10-01

415

Observations of Sprites Using High Spatial and Temporal Resolution Instruments  

NASA Astrophysics Data System (ADS)

In the 15 years since the accidental discovery of optical flashes above thunderstorms [Franz et al, 1990], now commonly termed sprites, the wide variety of spatial and temporal characteristics exhibited by these phenomena has challenged modeling efforts. The highly dynamic and variable structures observed in sprites can be classified either in terms of basic geometric descriptions (``cylinders," ``tendrils," ``branches," etc.) or by their apparent relation to features previously observed in laboratory gas discharges (i.e. ``streamers" and ``diffuse glow"). High-resolution imagery shows that the lower portion of a sprite typically consists of downward branching filaments, or positive streamers, while the middle to upper portions are made up of upward branching filaments, or negative streamers. The topmost part of a sprite is generally amorphous, or diffuse glow. Filamentary structures (streamers) have been observed to range in width from ˜20 - 200 m with the radius having some altitude dependence. Much of the observed streamer and diffuse glow structure can be explained in terms of conventional electrical gas discharge physics. Some features such as beads and low-altitude diffuse glows, however, are currently unexplained by any sprite model. This presentation describes the spatio-temporal characteristics of several sprites with various features as observed by 1) a high-spatial-resolution telescope, previously described in Gerken et al. [2000], with spatial resolution down to tens of meters, and ˜17 ms temporal resolution; and 2) similar events observed by a high-temporal-resolution ``high speed imager" with 1 ms temporal and approximately 300 m spatial resolution, previously described in Stenbaek-Nielsen et al. [2000]. Franz. R. C., R. J. Nemzek, and J. R. Winckler, Television image of a large upward electrical discharge above a thunderstorm, Science, 249, 48, 1990. Gerken, E. A., U. S. Inan, and C. P. Barrington-Leigh, Telescopic imaging of sprites, Geophys. Res. Lett., 27, 2637, 2000. Stenbaek-Nielsen, H. C., D. R. Moudry, E. M. Wescott, D. D. Sentman, and F. T. Sao Sabbas, Sprites and possible mesospheric effects, Geophys. Res. Lett., 27, 3829, 2000.

Gerken, E.; Moudry, D.

2004-12-01

416

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

417

Holographic Imaging: A Versatile Tool for High Angular Resolution Imaging  

NASA Astrophysics Data System (ADS)

Speckle holography can be used to reconstruct high angular resolution images from long series of short exposures if the point spread function (PSF) from each frame can be measured reliably. We show that through use of multiple reference stars and iterative PSF subtraction, we can obtain highly accurate PSFs. The technique is optimised for crowded fields and results in images with excellent cosmetics and high Strehl ratio from the optical to the mid-infrared regimes. With examples from NACO, VISIR, and HAWK-I we show that holography opens up novel and unforeseen possibilities and can be an attractive alternative to adaptive optics.

Schödel, R.; Girard, J. H.

2012-12-01

418

Dual collimation acquisition for high resolution, low noise SPECT  

SciTech Connect

This paper presents Dual Collimation (DC) imaging for SPECT as a technique to improve effective sensitivity with little loss of resolution. For some imaging tasks, DC can overcome the inherent tradeoff between resolution and sensitivity of gamma camera collimators. Simulations were used to investigate the system performance without the expense of collimator fabrication. The author implemented DC for SPECT using simulations of SPECT acquisition using two collimated gamma cameras. Projection data are acquired using two collimators simultaneously: a high sensitivity (HiSen) collimator and a high resolution (HiRes) collimator. Both projection data sets are used to reconstruct a single image using an Inverse Monte Carlo (IMOC) technique with Maximum Likelihood Expectation Maximization (MLEM). Accurate modeling of each collimator is included in the IMOC technique and the reconstructed image is constrained to be consistent with both projection sets. Monte Carlo modeling simulated projection acquisition from two phantoms: a resolution-noise and a cold defect contrast phantom. Projections were simulated for acquisitions of 200K counts with a dual gamma camera HiRes system, yielding 1.9M for an equal time scan using DC (1.8 million counts in the HiSen; 100K in the HiRes). After 300 iterations (10 min), %rms noise decreased for DC (compared to HiRes with equal scan time) by a factor of 7 with an increase in reconstructed line-source width from 9 to 10 mm FWHM. For a 2 cm radius defect, contrast decreased 4% (from 0.90 to 0.86) while contrast-to-noise (CNR) increased 210%. For a1 cm defect, contrast decreased 40% while CNR increased 200%. Thus for a select class of imaging tasks, Dual Collimation for SPECT can provide significant improvements in signal-to-noise with only a modest sacrifice of system resolution and contrast.

Floyd, C.E. Jr.; Munley, M.T.; Tourassi, G.D.; Bowsher, J.E. (Duke Univ., Durham, NC (United States). Dept. of Radiology)

1991-04-01

419

High-resolution diffusion-weighted imaging of the prostate.  

PubMed

OBJECTIVE. The purpose of this study was to evaluate the effect of increasing the spatial resolution of the prostate DWI protocol on image quality and lesion conspicuity. SUBJECTS AND METHODS. Twenty-nine patients with biopsy-proven prostate cancer undergoing MRI examinations were imaged with two diffusion-weighted imaging (DWI) protocols: current standard clinical protocol (6.7 mm(3) voxels) and a new high-resolution protocol (3.1 mm(3) voxels). Diffusion-weighted images were independently and subjectively scored on lesion conspicuity, internal architecture definition, and overall image quality by two radiologists. Average apparent diffusion coefficient (ADC) values were measured in normal tissue and cancerous lesions on both sequences. Reader scores and ADC and contrast values were compared between the two protocols. Cancer ADC values were correlated with Gleason scores. RESULTS. The signal-to-noise ratio of the new high-resolution DWI protocol was 40% lower than that of the standard protocol. The reader scores were higher by 0.73 (range, 0.29-1.16) grades, or 19% (range, 7-32%), on average, for the new protocol, indicating better image quality. The average ADC values were 8% higher with the new protocol, with ADC contrast values between cancer and normal prostate unchanged. There was marginally significant correlation of cancer ADC values with Gleason scores (p = 0.05, r ? -0.36). CONCLUSION. We showed that for DWI of the prostate at 3-7 mm(3) voxel sizes the benefits of higher spatial resolution outweigh the effects of reduced signal-to-noise and contrast-to-noise ratios, potentially improving the sensitivity to small or sparse prostate cancers. Radiologists can consider using higher-spatial-resolution DWI sequences in their practices. PMID:24951199

Medved, Milica; Soylu-Boy, Fatma N; Karademir, Ibrahim; Sethi, Ila; Yousuf, Ambereen; Karczmar, Gregory S; Oto, Aytekin

2014-07-01

420

Sun glint correction of very high spatial resolution images  

NASA Astrophysics Data System (ADS)

Sun glint is often evident in remotely sensed imagery data of very high spatial resolution that depict aquatic environment. The problem occurs when the water surface is not flat and the sun radiation is directly reflected to the sensor affecting the pixel brightness values. The state of water surface, sun position and viewing angle are the main function parameters to estimate glint effect on the images. The removal of glint is compulsory since multispectral bathymetry and bottom types mapping are affected unfavourably. In this paper two widely applied methodologies were investigated towards correcting from sun glint effect optical satellite images of very high spatial resolution. Particularly, the approaches proposed by Lyzenga (1985) and Hedley et al. (2005) were applied on images acquired by Ikonos-2 and Worldview-2. The experimental results indicated the effectiveness of both methods in correcting glint contaminated imagery datasets.

Doxani, G.; Papadopoulou, M.; Lafazani, P.; Tsakiri-Strati, M.; Mavridou, E.

2013-01-01

421

High resolution imaging systems for inertial confinement fusion experiments  

NASA Astrophysics Data System (ADS)

The path to successful inertial confinement fusion (ICF) requires to observe and control the micro balloon deformations. This will be achieved using X-ray microscope among other diagnostics. A high resolution, high energy X-ray microscope involving state-of-the-art toroidal mirrors and multilayer coatings is described. Years of experiments and experience have led to a small-scale X-ray plasma imager that proves the feasibility of all the features required for a LMJ diagnostic: spatial resolution of 5?m, broad bandwidth, millimetric field of view (FOV). Using the feedback given by this diagnostic, a prototype for the Laser MegaJoule (LMJ) experiments has been designed. The experimental results of the first diagnostic and the concepts of the second are discussed.

Dennetiere, D.; Audebert, P.; Bahr, R.; Bole, S.; Bourgade, J. L.; Brannon, B.; Girard, F.; Pien, G.; Troussel, Ph.

2012-10-01

422

High resolution irradiance tailoring using multiple freeform surfaces.  

PubMed

More and more lighting applications require the design of dedicated optics to achieve a given radiant intensity or irradiance distribution. Freeform optics has the advantage of providing such a functionality with a compact design. It was previously demonstrated in [Bäuerle et al., Opt. Exp. 20, 14477-14485 (2012)] that the up-front computation of the light path through the optical system (ray mapping) provides a satisfactory approximation to the problem, and allows the design of multiple freeform surfaces in transmission or in reflection. This article presents one natural extension of this work by introducing an efficient optimization procedure based on the physics of the system. The procedure allows the design of multiple freeform surfaces and can render high resolution irradiance patterns, as demonstrated by several examples, in particular by a lens made of two freeform surfaces projecting a high resolution logo (530 × 160 pixels). PMID:23669912

Bruneton, Adrien; Bäuerle, Axel; Wester, Rolf; Stollenwerk, Jochen; Loosen, Peter

2013-05-01

423

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

424

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

425

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 years—the 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.

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

2014-01-01

426

Fabricating High-Resolution X-Ray Collimators  

NASA Technical Reports Server (NTRS)

A process and method for fabricating multi-grid, high-resolution rotating modulation collimators for arcsecond and sub-arcsecond x-ray and gamma-ray imaging involves photochemical machining and precision stack lamination. The special fixturing and etching techniques that have been developed are used for the fabrication of multiple high-resolution grids on a single array substrate. This technology has application in solar and astrophysics and in a number of medical imaging applications including mammography, computed tomography (CT), single photon emission computed tomography (SPECT), and gamma cameras used in nuclear medicine. This collimator improvement can also be used in non-destructive testing, hydrodynamic weapons testing, and microbeam radiation therapy.

Appleby, Michael; Atkinson, James E.; Fraser, Iain; Klinger, Jill

2008-01-01

427

Dynamical downscaling inter-comparison for high resolution climate reconstruction  

NASA Astrophysics Data System (ADS)

In the scope of the project: "High-resolution Rainfall EroSivity analysis and fORecasTing - RESORT", an evaluation of various methods of dynamic downscaling is presented. The methods evaluated range from the classic method of nesting a regional model results in a global model, in this case the ECMWF reanalysis, to more recently proposed methods, which consist in using Newtonian relaxation methods in order to nudge the results of the regional model to the reanalysis. The method with better results involves using a system of variational data assimilation to incorporate observational data with results from the regional model. The climatology of a simulation of 5 years using this method is tested against observations on mainland Portugal and the ocean in the area of the Portuguese Continental Shelf, which shows that the method developed is suitable for the reconstruction of high resolution climate over continental Portugal.

Ferreira, J.; Rocha, A.; Castanheira, J. M.; Carvalho, A. C.

2012-04-01

428

High Resolution Coherent 3d Spectroscopy of Bromine  

NASA Astrophysics Data System (ADS)

The high resolution gas phase electronic spectrum of bromine is rather congested due to many overlapping vibrational and rotational transitions with similar transition frequencies, and also due to isotopomeric effects. Expansion into the second dimension will remove some of this congestion; however through the implementation of High Resolution Coherent 3D Spectroscopy, the density of peaks is further reduced by at least two orders of magnitude. This allows for the selective examination of a small number of spatially resolved multidimensional bands, separated by vibrational quantum number and by isotopomer, which facilitates the fitting of many rovibrational peaks in bromine. The ability to derive information about the molecular constants for the electronic states involved will be discussed.

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

2013-06-01

429

Coupled Analysis and Visualization of High Resolution Astrophysical Simulations  

NASA Astrophysics Data System (ADS)

Computational physics has benefited from on-going microprocessor innovations, which have enabled larger and larger numerical simulations. One consequence of these technological advancements has been an explosion in the amount of data generated. For many modelers, available software tools and computing resources are proving inadequate for investigation of high-resolution numerical outputs. In this paper we discuss the general problems associated with very large data visualization and analysis and our work on a particular solution to those through the development of VAPOR (open source, available at http://www.vapor.ucar.edu): a desktop application that leverages today's powerful CPUs and GPUs to enable visualization and analysis of terascale data sets using only a commodity PC or laptop. We briefly illustrate VAPOR's utility through the exploration of a high-resolution simulation aimed at understanding the effects of hydrogen ionization on convective dynamics in stellar envelopes.

Rast, M.; Clyne, J.

2008-04-01

430

High-resolution ultrasound imaging of cutaneous lesions  

PubMed Central

High-resolution variable frequency ultrasound imaging is increasingly being used in the noninvasive evaluation of various cutaneous diseases. It plays a complimentary role to physical examination in the assessment of cutaneous lesions. It is the only imaging modality useful in the evaluation of superficial cutaneous lesions that are too small to be evaluated on computed tomography (CT) or magnetic resonance imaging (MRI) and is helpful in reducing invasive procedures like biopsies and fine needle aspirations. In this article, we seek to describe the relevance and basic principles of cutaneous ultrasound, imaging findings of normal skin, current applications of high-resolution ultrasound in the diagnosis and management of various dermatological conditions, along with the features of some commonly encountered lesions.

Mandava, Anitha; Ravuri, Prabhakar Rao; Konathan, Rajyalaxmi

2013-01-01

431