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Sample records for acquisition single-shot turbo

  1. Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

    NASA Astrophysics Data System (ADS)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-01-01

    A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p < 0.05). In addition, the presence of artifacts, the image clarity and the overall image quality were excellent at TE = 128 msec (p < 0.05). In abdominal MRI, the breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

  2. Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

    PubMed Central

    Chan, Queenie; Wáng, Yì-Xiáng J.

    2016-01-01

    Background Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion. Methods A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms. Results Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression. Conclusions A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods. PMID:27190769

  3. Reference-free unwarping of single-shot spatiotemporally encoded MRI using asymmetric self-refocused echoes acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Chen, Song; Zhong, Jianhui; Chen, Zhong

    2015-05-01

    This paper presents a phase evolution rewinding algorithm for correcting the geometric and intensity distortions in single-shot spatiotemporally encoded (SPEN) MRI with acquisition of asymmetric self-refocused echo trains. Using the field map calculated from the phase distribution of the source image, the off-resonance induced phase errors are successfully rewound through deconvolution. The alias-free partial Fourier transform reconstruction helps improve the signal-to-noise ratio of the field maps and the output images. The effectiveness of the proposed algorithm was validated through 7 T MRI experiments on a lemon, a water phantom, and in vivo rat head. SPEN imaging was evaluated using rapid acquisition by sequential excitation and refocusing (RASER) which produces uniform T2 weighting. The results indicate that the new technique can more robustly deal with the cases in which the images obtained with conventional single-shot spin-echo EPI are difficult to be restored due to serious field variations.

  4. A single-shot, multiwavelength electro-optic data-acquisition system for inertial confinement fusion applications (invited)

    SciTech Connect

    Donaldson, W. R.; Zhao, C.; Ji, L.; Roides, R. G.; Miller, K.; Beeman, B.

    2012-10-15

    Electro-optic data-acquisition systems encode the output from voltage-history diagnostics onto optical signals. The optical signals can propagate long distances over fiber-optic links without degrading the bandwidth of the encoded signal while protecting the recording electronics from overvoltage damage. The sinusoidal response and tolerance to high-input voltages of the Mach-Zehnder modulator used for the encoding leads to the additional advantage of a high dynamic range and a reduced need for manually swapping attenuators. We have demonstrated a single-shot, electro-optic data-acquisition system with a 600:1 dynamic range. This system provides optical isolation and a bandwidth of 6 GHz. The prototype system uses multiple optical wavelengths to allow for the multiplexing of up to eight signals onto one photodetector.

  5. Enhancement of BOLD-contrast sensitivity by single-shot multi-echo functional MR imaging.

    PubMed

    Posse, S; Wiese, S; Gembris, D; Mathiak, K; Kessler, C; Grosse-Ruyken, M L; Elghahwagi, B; Richards, T; Dager, S R; Kiselev, V G

    1999-07-01

    Improved data acquisition and processing strategies for blood oxygenation level-dependent (BOLD)-contrast functional magnetic resonance imaging (fMRI), which enhance the functional contrast-to-noise ratio (CNR) by sampling multiple echo times in a single shot, are described. The dependence of the CNR on T2*, the image encoding time, and the number of sampled echo times are investigated for exponential fitting, echo summation, weighted echo summation, and averaging of correlation maps obtained at different echo times. The method is validated in vivo using visual stimulation and turbo proton echoplanar spectroscopic imaging (turbo-PEPSI), a new single-shot multi-slice MR spectroscopic imaging technique, which acquires up to 12 consecutive echoplanar images with echo times ranging from 12 to 213 msec. Quantitative T2*-mapping significantly increases the measured extent of activation and the mean correlation coefficient compared with conventional echoplanar imaging. The sensitivity gain with echo summation, which is computationally efficient provides similar sensitivity as fitting. For all data processing methods sensitivity is optimum when echo times up to 3.2 T2* are sampled. This methodology has implications for comparing functional sensitivity at different magnetic field strengths and between brain regions with different magnetic field inhomogeneities.

  6. Enhancement of BOLD-contrast sensitivity by single-shot multi-echo functional MR imaging.

    PubMed

    Posse, S; Wiese, S; Gembris, D; Mathiak, K; Kessler, C; Grosse-Ruyken, M L; Elghahwagi, B; Richards, T; Dager, S R; Kiselev, V G

    1999-07-01

    Improved data acquisition and processing strategies for blood oxygenation level-dependent (BOLD)-contrast functional magnetic resonance imaging (fMRI), which enhance the functional contrast-to-noise ratio (CNR) by sampling multiple echo times in a single shot, are described. The dependence of the CNR on T2*, the image encoding time, and the number of sampled echo times are investigated for exponential fitting, echo summation, weighted echo summation, and averaging of correlation maps obtained at different echo times. The method is validated in vivo using visual stimulation and turbo proton echoplanar spectroscopic imaging (turbo-PEPSI), a new single-shot multi-slice MR spectroscopic imaging technique, which acquires up to 12 consecutive echoplanar images with echo times ranging from 12 to 213 msec. Quantitative T2*-mapping significantly increases the measured extent of activation and the mean correlation coefficient compared with conventional echoplanar imaging. The sensitivity gain with echo summation, which is computationally efficient provides similar sensitivity as fitting. For all data processing methods sensitivity is optimum when echo times up to 3.2 T2* are sampled. This methodology has implications for comparing functional sensitivity at different magnetic field strengths and between brain regions with different magnetic field inhomogeneities. PMID:10398954

  7. Method and device for measuring single-shot transient signals

    DOEpatents

    Yin, Yan

    2004-05-18

    Methods, apparatus, and systems, including computer program products, implementing and using techniques for measuring multi-channel single-shot transient signals. A signal acquisition unit receives one or more single-shot pulses from a multi-channel source. An optical-fiber recirculating loop reproduces the one or more received single-shot optical pulses to form a first multi-channel pulse train for circulation in the recirculating loop, and a second multi-channel pulse train for display on a display device. The optical-fiber recirculating loop also optically amplifies the first circulating pulse train to compensate for signal losses and performs optical multi-channel noise filtration.

  8. Single-shot T1 mapping using simultaneous acquisitions of spin- and stimulated-echo-planar imaging (2D ss-SESTEPI).

    PubMed

    Shi, Xianfeng; Kim, Seong-Eun; Jeong, Eun-Kee

    2010-09-01

    The conventional stimulated-echo NMR sequence only measures the longitudinal component while discarding the transverse component, after tipping up the prepared magnetization. This transverse magnetization can be used to measure a spin echo, in addition to the stimulated echo. Two-dimensional single-shot spin- and stimulated-echo-planar imaging (ss-SESTEPI) is an echo-planar-imaging-based single-shot imaging technique that simultaneously acquires a spin-echo-planar image and a stimulated-echo-planar image after a single radiofrequency excitation. The magnitudes of the spin-echo-planar image and stimulated-echo-planar image differ by T(1) decay and diffusion weighting for perfect 90 degrees radiofrequency and thus can be used to rapidly measure T(1). However, the spatial variation of amplitude of radiofrequency field induces uneven splitting of the transverse magnetization for the spin-echo-planar image and stimulated-echo-planar image within the imaging field of view. Correction for amplitude of radiofrequency field inhomogeneity is therefore critical for two-dimensional ss-SESTEPI to be used for T(1) measurement. We developed a method for amplitude of radiofrequency field inhomogeneity correction by acquiring an additional stimulated-echo-planar image with minimal mixing time, calculating the difference between the spin echo and the stimulated echo and multiplying the stimulated-echo-planar image by the inverse functional map. Diffusion-induced decay is corrected by measuring the average diffusivity during the prescanning. Rapid single-shot T(1) mapping may be useful for various applications, such as dynamic T(1) mapping for real-time estimation of the concentration of contrast agent in dynamic contrast enhancement MRI.

  9. Development of a single-shot CCD-based data acquisition system for time-resolved X-ray photoelectron spectroscopy at an X-ray free-electron laser facility

    PubMed Central

    Oura, Masaki; Wagai, Tatsuya; Chainani, Ashish; Miyawaki, Jun; Sato, Hiromi; Matsunami, Masaharu; Eguchi, Ritsuko; Kiss, Takayuki; Yamaguchi, Takashi; Nakatani, Yasuhiro; Togashi, Tadashi; Katayama, Tetsuo; Ogawa, Kanade; Yabashi, Makina; Tanaka, Yoshihito; Kohmura, Yoshiki; Tamasaku, Kenji; Shin, Shik; Ishikawa, Tetsuya

    2014-01-01

    In order to utilize high-brilliance photon sources, such as X-ray free-electron lasers (XFELs), for advanced time-resolved photoelectron spectroscopy (TR-PES), a single-shot CCD-based data acquisition system combined with a high-resolution hemispherical electron energy analyzer has been developed. The system’s design enables it to be controlled by an external trigger signal for single-shot pump–probe-type TR-PES. The basic performance of the system is demonstrated with an offline test, followed by online core-level photoelectron and Auger electron spectroscopy in ‘single-shot image’, ‘shot-to-shot image (image-to-image storage or block storage)’ and ‘shot-to-shot sweep’ modes at soft X-ray undulator beamline BL17SU of SPring-8. In the offline test the typical repetition rate for image-to-image storage mode has been confirmed to be about 15 Hz using a conventional pulse-generator. The function for correcting the shot-to-shot intensity fluctuations of the exciting photon beam, an important requirement for the TR-PES experiments at FEL sources, has been successfully tested at BL17SU by measuring Au 4f photoelectrons with intentionally controlled photon flux. The system has also been applied to hard X-ray PES (HAXPES) in ‘ordinary sweep’ mode as well as shot-to-shot image mode at the 27 m-long undulator beamline BL19LXU of SPring-8 and also at the SACLA XFEL facility. The XFEL-induced Ti 1s core-level spectrum of La-doped SrTiO3 is reported as a function of incident power density. The Ti 1s core-level spectrum obtained at low power density is consistent with the spectrum obtained using the synchrotron source. At high power densities the Ti 1s core-level spectra show space-charge effects which are analysed using a known mean-field model for ultrafast electron packet propagation. The results successfully confirm the capability of the present data acquisition system for carrying out the core-level HAXPES studies of condensed matter induced by the

  10. Development of a single-shot CCD-based data acquisition system for time-resolved X-ray photoelectron spectroscopy at an X-ray free-electron laser facility.

    PubMed

    Oura, Masaki; Wagai, Tatsuya; Chainani, Ashish; Miyawaki, Jun; Sato, Hiromi; Matsunami, Masaharu; Eguchi, Ritsuko; Kiss, Takayuki; Yamaguchi, Takashi; Nakatani, Yasuhiro; Togashi, Tadashi; Katayama, Tetsuo; Ogawa, Kanade; Yabashi, Makina; Tanaka, Yoshihito; Kohmura, Yoshiki; Tamasaku, Kenji; Shin, Shik; Ishikawa, Tetsuya

    2014-01-01

    In order to utilize high-brilliance photon sources, such as X-ray free-electron lasers (XFELs), for advanced time-resolved photoelectron spectroscopy (TR-PES), a single-shot CCD-based data acquisition system combined with a high-resolution hemispherical electron energy analyzer has been developed. The system's design enables it to be controlled by an external trigger signal for single-shot pump-probe-type TR-PES. The basic performance of the system is demonstrated with an offline test, followed by online core-level photoelectron and Auger electron spectroscopy in 'single-shot image', 'shot-to-shot image (image-to-image storage or block storage)' and `shot-to-shot sweep' modes at soft X-ray undulator beamline BL17SU of SPring-8. In the offline test the typical repetition rate for image-to-image storage mode has been confirmed to be about 15 Hz using a conventional pulse-generator. The function for correcting the shot-to-shot intensity fluctuations of the exciting photon beam, an important requirement for the TR-PES experiments at FEL sources, has been successfully tested at BL17SU by measuring Au 4f photoelectrons with intentionally controlled photon flux. The system has also been applied to hard X-ray PES (HAXPES) in `ordinary sweep' mode as well as shot-to-shot image mode at the 27 m-long undulator beamline BL19LXU of SPring-8 and also at the SACLA XFEL facility. The XFEL-induced Ti 1s core-level spectrum of La-doped SrTiO3 is reported as a function of incident power density. The Ti 1s core-level spectrum obtained at low power density is consistent with the spectrum obtained using the synchrotron source. At high power densities the Ti 1s core-level spectra show space-charge effects which are analysed using a known mean-field model for ultrafast electron packet propagation. The results successfully confirm the capability of the present data acquisition system for carrying out the core-level HAXPES studies of condensed matter induced by the XFEL. PMID:24365935

  11. Development of a single-shot CCD-based data acquisition system for time-resolved X-ray photoelectron spectroscopy at an X-ray free-electron laser facility.

    PubMed

    Oura, Masaki; Wagai, Tatsuya; Chainani, Ashish; Miyawaki, Jun; Sato, Hiromi; Matsunami, Masaharu; Eguchi, Ritsuko; Kiss, Takayuki; Yamaguchi, Takashi; Nakatani, Yasuhiro; Togashi, Tadashi; Katayama, Tetsuo; Ogawa, Kanade; Yabashi, Makina; Tanaka, Yoshihito; Kohmura, Yoshiki; Tamasaku, Kenji; Shin, Shik; Ishikawa, Tetsuya

    2014-01-01

    In order to utilize high-brilliance photon sources, such as X-ray free-electron lasers (XFELs), for advanced time-resolved photoelectron spectroscopy (TR-PES), a single-shot CCD-based data acquisition system combined with a high-resolution hemispherical electron energy analyzer has been developed. The system's design enables it to be controlled by an external trigger signal for single-shot pump-probe-type TR-PES. The basic performance of the system is demonstrated with an offline test, followed by online core-level photoelectron and Auger electron spectroscopy in 'single-shot image', 'shot-to-shot image (image-to-image storage or block storage)' and `shot-to-shot sweep' modes at soft X-ray undulator beamline BL17SU of SPring-8. In the offline test the typical repetition rate for image-to-image storage mode has been confirmed to be about 15 Hz using a conventional pulse-generator. The function for correcting the shot-to-shot intensity fluctuations of the exciting photon beam, an important requirement for the TR-PES experiments at FEL sources, has been successfully tested at BL17SU by measuring Au 4f photoelectrons with intentionally controlled photon flux. The system has also been applied to hard X-ray PES (HAXPES) in `ordinary sweep' mode as well as shot-to-shot image mode at the 27 m-long undulator beamline BL19LXU of SPring-8 and also at the SACLA XFEL facility. The XFEL-induced Ti 1s core-level spectrum of La-doped SrTiO3 is reported as a function of incident power density. The Ti 1s core-level spectrum obtained at low power density is consistent with the spectrum obtained using the synchrotron source. At high power densities the Ti 1s core-level spectra show space-charge effects which are analysed using a known mean-field model for ultrafast electron packet propagation. The results successfully confirm the capability of the present data acquisition system for carrying out the core-level HAXPES studies of condensed matter induced by the XFEL.

  12. Single shot line-field optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Liu, Chih-Hao; Schill, Alexander; Singh, Manmohan; Wu, Chen; Li, Jiasong; Han, Zhaolong; Raghunathan, Raksha; Kazemi, Tina; Nair, Achuth; Hsu, Thomas; Larin, Kirill V.

    2016-03-01

    Elastic wave imaging optical coherence elastography (EWI-OCE) is an emerging technique that can quantify local biomechanical properties of tissues. However, long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate a noncontact single shot line-field OCE technique using a line-field interferometer and an air-pulse delivery system. The spatial-temporal elastic wave propagation profile was acquired in a single shot and used to quantify the elastic wave group velocity in tissue. Results on tissue-mimicking phantoms and chicken breast muscle agreed well with mechanical compression testing, demonstrating that the presented method can effectively reduce the OCE acquisition time to a few milliseconds in biological application.

  13. Ultrafast single-shot measurement of optical Kerr effect based on supercontinuum pulse.

    PubMed

    Zhang, Jian; Liu, Shenye; Yi, Tao; Wu, Xingzhi; Song, Yinglin; Zhang, Ben; Zhong, Quanjie

    2016-04-01

    We present an ultrafast single-shot measurement method for the optical Kerr effect based on a polarization gating technique. The advantages of this single-shot technique are demonstrated via a 26-ps chirped supercontinuum pulse used to measure the optical Kerr effect for three transparent organic liquids. The single-shot measurement results agree well with those of the time-resolved optical Kerr gate method, as regards both time and intensity. This method facilitates real-time observation of ultrafast optical Kerr responses of samples and simultaneous high-time-resolution data acquisition at ∼260 fs. We demonstrate that the single-shot measurement method is potentially a powerful tool for investigating the optical Kerr effects of unstable samples, and for application to high-power laser systems. PMID:27131661

  14. Ultrafast single-shot measurement of optical Kerr effect based on supercontinuum pulse

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Liu, Shenye; Yi, Tao; Wu, Xingzhi; Song, Yinglin; Zhang, Ben; Zhong, Quanjie

    2016-04-01

    We present an ultrafast single-shot measurement method for the optical Kerr effect based on a polarization gating technique. The advantages of this single-shot technique are demonstrated via a 26-ps chirped supercontinuum pulse used to measure the optical Kerr effect for three transparent organic liquids. The single-shot measurement results agree well with those of the time-resolved optical Kerr gate method, as regards both time and intensity. This method facilitates real-time observation of ultrafast optical Kerr responses of samples and simultaneous high-time-resolution data acquisition at ˜260 fs. We demonstrate that the single-shot measurement method is potentially a powerful tool for investigating the optical Kerr effects of unstable samples, and for application to high-power laser systems.

  15. Spectrally resolving single-shot polarimeter.

    PubMed

    Knitter, Sebastian; Hellwig, Tim; Kues, Michael; Fallnich, Carsten

    2011-08-15

    We demonstrate a spectrally resolving single-shot polarimeter. The system consists of a commercial imaging spectrograph, modified by a birefringent wedge and a segmented polarizer. The physical operating principle and limitations of the apparatus as well as preliminary polarimetric measurements on the emission of random lasers are reported. PMID:21847155

  16. Diffusion weighted inner volume imaging of lumbar disks based on turbo-STEAM acquisition.

    PubMed

    Hiepe, Patrick; Herrmann, Karl-Heinz; Ros, Christian; Reichenbach, Jürgen R

    2011-09-01

    A magnetic resonance imaging (MRI) technique for diffusion weighted imaging (DWI) is described which, in contrast to echo planar imaging (EPI), is insensitive to off-resonance effects caused by tissue susceptibility differences, magnetic field inhomogeneities, or chemical shifts. The sequence combines a diffusion weighted (DW) spin-echo preparation and a stimulated echo acquisition mode (STEAM) module. Inner volume imaging (IVI) allows reduced rectangular field-of-view (FoV) in the phase encode direction, while suppressing aliasing artifacts that are usually the consequence of reduced FoVs. Sagittal turbo-STEAM images of the lumbar spine were acquired at 3.0T with 2.0 × 2.0 mm² in-plane resolution and 7 mm slice thickness with acquisition times of 407 ms per image. To calculate the apparent diffusion coefficient (ADC) in lumbar intervertebral disks (IVDs), the DW gradients were applied in three orthogonal gradient directions with b-values of 0 and 300 s/mm². For initial assessment of the ADC of normal and abnormal IVDs a pilot study with 8 subjects was performed. Mean ADC values of all normal IVDs were (2.27±0.40)×10⁻³ mm²/s and (1.89±0.34)×10⁻³ mm²/s for turbo-STEAM IVI and SE-EPI acquisition, respectively. Corresponding mean ADC values, averaged over all abnormal disks, were (1.93±0.39)×10⁻³ mm²/s and (1.51±0.46)×10⁻³ mm²/s, respectively, indicating a substantial ADC decrease (p<0.001).

  17. Dual echelon femtosecond single-shot spectroscopy

    SciTech Connect

    Shin, Taeho; Wolfson, Johanna W.; Teitelbaum, Samuel W.; Kandyla, Maria; Nelson, Keith A.

    2014-08-15

    We have developed a femtosecond single-shot spectroscopic technique to measure irreversible changes in condensed phase materials in real time. Crossed echelons generate a two-dimensional array of time-delayed pulses with one femtosecond probe pulse. This yields 9 ps of time-resolved data from a single laser shot, filling a gap in currently employed measurement methods. We can now monitor ultrafast irreversible dynamics in solid-state materials or other samples that cannot be flowed or replenished between laser shots, circumventing limitations of conventional pump-probe methods due to sample damage or product buildup. Despite the absence of signal-averaging in the single-shot measurement, an acceptable signal-to-noise level has been achieved via background and reference calibration procedures. Pump-induced changes in relative reflectivity as small as 0.2%−0.5% are demonstrated in semimetals, with both electronic and coherent phonon dynamics revealed by the data. The optical arrangement and the space-to-time conversion and calibration procedures necessary to achieve this level of operation are described. Sources of noise and approaches for dealing with them are discussed.

  18. Optical encryption in single shot digital holography

    NASA Astrophysics Data System (ADS)

    Lin, Ching-Yang; Chen, Gu-Liang; Kuo, Ming-Kuei; Chang, Chi-Ching; Yau, Hon-Fai

    2007-09-01

    We propose a novel optical encryption approach using a lenticular lens array (LLA) as a deterministic phase modulator and the single-shot digital holographic scheme. In the proposed scheme, the input amplitude image is encrypted and interferes with the reference wave phase, which is modulated by a LLA, then recorded holographically by a digital CCD camera to form an encrypted hologram. A decryption key is obtained from the key hologram using numerical reconstruction. The image is decrypted using a digital holographic approach after which the encrypted hologram is multiplying the numerical reconstructed key for decryption. The experimental results show that only an encrypted hologram is needed. Moreover with this approach, the decryption procedure can be rapidly accomplished using a personal computer, presenting a decrypted image of satisfactory image quality. Finally the selective sensitivity of the key rotation is also investigated.

  19. SNR-optimized phase-sensitive dual-acquisition turbo spin echo imaging: a fast alternative to FLAIR.

    PubMed

    Lee, Hyunyeol; Park, Jaeseok

    2013-07-01

    Phase-sensitive dual-acquisition single-slab three-dimensional turbo spin echo imaging was recently introduced, producing high-resolution isotropic cerebrospinal fluid attenuated brain images without long inversion recovery preparation. Despite the advantages, the weighted-averaging-based technique suffers from noise amplification resulting from different levels of cerebrospinal fluid signal modulations over the two acquisitions. The purpose of this work is to develop a signal-to-noise ratio-optimized version of the phase-sensitive dual-acquisition single-slab three-dimensional turbo spin echo. Variable refocusing flip angles in the first acquisition are calculated using a three-step prescribed signal evolution while those in the second acquisition are calculated using a two-step pseudo-steady state signal transition with a high flip-angle pseudo-steady state at a later portion of the echo train, balancing the levels of cerebrospinal fluid signals in both the acquisitions. Low spatial frequency signals are sampled during the high flip-angle pseudo-steady state to further suppress noise. Numerical simulations of the Bloch equations were performed to evaluate signal evolutions of brain tissues along the echo train and optimize imaging parameters. In vivo studies demonstrate that compared with conventional phase-sensitive dual-acquisition single-slab three-dimensional turbo spin echo, the proposed optimization yields 74% increase in apparent signal-to-noise ratio for gray matter and 32% decrease in imaging time. The proposed method can be a potential alternative to conventional fluid-attenuated imaging.

  20. Coupled metric learning for single-shot versus single-shot person reidentification

    NASA Astrophysics Data System (ADS)

    Li, Wei; Wu, Yang; Mukunoki, Masayuki; Minoh, Michihiko

    2013-02-01

    Person reidentification tackles the problem of building a correspondence between different images of the same person captured by distributed cameras. To date, attempts to solve this problem have focused on either feature representation or learning methods. Usually, the greater the number of the samples for each person, the better the reidentification performance is. However, in the real world, we may not be able to acquire enough samples to give acceptable performance. Here, we focus on the so-called "single-shot versus single-shot" problem: matching one image of a person to another. Because of the extremely small sample class size, there is limited scope to statistically weaken the empirical risk for hand-crafted feature representation. Therefore, we resort to metric learning methods, such as the ranking-specialized metric learning to rank (MLR) and the classification-based maximally collapsing metric learning (MCML). Taking advantage of the complementarity between them, we propose a novel "coupled metric learning" approach. This searches for the optimal linear projection for the original feature space using MCML before minimizing the ranking loss via MLR. Experiments on widely used benchmark datasets show encouraging results.

  1. A single-shot optical linear polarimeter for asteroid studies

    NASA Astrophysics Data System (ADS)

    Pernechele, C.; Abe, L.; Bendjoya, P.; Cellino, A.; Massone, G.; Rivet, J. P.; Tanga, P.

    2012-09-01

    Polarimetric studies of minor Solar System bodies are useful to access physical parameters, such as albedo and diameter, which are both important and difficult to derive by other techniques. Current activities in this field are limited since most instruments adopted in recent observing campaigns involve photomultipliers detectors. These sensors are suitable for observations of objects with fast polarization variations, but usually suffer from low quantum efficiency. This severely limits the number of accessible targets. For asteroids, the polarization evolves slowly enough to allow more sensitive albeit slower detectors (CCD-based polarimeters). However, polarimetric measurement accuracy may be hampered with usual "sequential" polarimeters. Indeed, retarder plate swapping time, readout and exposure time add up. Consequently, the time laps between complementary polarization measurements (some minutes) may be non-negligible in some cases, compared to the evolution time of the polarization parameters. Moreover, polarimetric accuracy may also be limited by airmass variations between complementary exposures. We are developing a new "single-shot" CCD polarimeter based on a "double-Wollaston" configuration already described in literature [9][10]. This allows simultaneous acquisition of the three Stokes parameters I, Q, U without any moving parts. So, the linear polarization degree can be measured accurately, even for targets with fast polarization and/or airmass variations. Presently, the polarization analyzer is in calibration phase, and will be installed soon at the F/12.5 Cassegrain focus of the West telescope at the "Centre Pédagogique Planète et Univers" facility (C2PU, Observatoire de la Côte d'Azur, Plateau de Calern, France).

  2. Single-shot positron annihilation lifetime spectroscopy with LYSO scintillators

    NASA Astrophysics Data System (ADS)

    Alonso, A. M.; Cooper, B. S.; Deller, A.; Cassidy, D. B.

    2016-08-01

    We have evaluated the application of a lutetium yttrium oxyorthosilicate (LYSO) based detector to single-shot positron annihilation lifetime spectroscopy. We compare this detector directly with a similarly configured PbWO4 scintillator, which is the usual choice for such measurements. We find that the signal to noise ratio obtained using LYSO is around three times higher than that obtained using PbWO4 for measurements of Ps excited to longer-lived (Rydberg) levels, or when they are ionized soon after production. This is due to the much higher light output for LYSO (75% and 1% of NaI for LYSO and PbWO4 respectively). We conclude that LYSO is an ideal scintillator for single-shot measurements of positronium production and excitation performed using a low-intensity pulsed positron beam.

  3. Single shot cell irradiations with laser-driven protons

    SciTech Connect

    Humble, N.; Schmid, T. E.; Zlobinskaya, O.; Wilkens, J. J.; Allinger, K.; Hilz, P.; Ma, W.; Reinhardt, S.; Bin, J.; Kiefer, D.; Schreiber, J.; Drexler, G. A.; Friedl, A.

    2013-07-26

    Ion beams are relevant for radiobiological studies in basic research and for application in tumor therapy. Here we present a method to generate nanosecond proton bunches with single shot doses of up to 7 Gray by a tabletop high-power laser. Although in their infancy, laser-ion accelerators allow studying fast radiobiological processes at small-scale laboratories as exemplarily demonstrated by measurements of the relative biological effectiveness of protons in human tumor cells.

  4. Non-contact single shot elastography using line field low coherence holography

    PubMed Central

    Liu, Chih-Hao; Schill, Alexander; Wu, Chen; Singh, Manmohan; Larin, Kirill V.

    2016-01-01

    Optical elastic wave imaging is a powerful technique that can quantify local biomechanical properties of tissues. However, typically long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate non-contact single shot elastographic holography using a line-field interferometer integrated with an air-pulse delivery system. The propagation of the air-pulse induced elastic wave was imaged in real time, and required a single excitation for a line-scan measurement. Results on tissue-mimicking phantoms and chicken breast muscle demonstrated the feasibility of this technique for accurate assessment of tissue biomechanical properties with an acquisition time of a few milliseconds using parallel acquisition. PMID:27570694

  5. Non-contact single shot elastography using line field low coherence holography.

    PubMed

    Liu, Chih-Hao; Schill, Alexander; Wu, Chen; Singh, Manmohan; Larin, Kirill V

    2016-08-01

    Optical elastic wave imaging is a powerful technique that can quantify local biomechanical properties of tissues. However, typically long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate non-contact single shot elastographic holography using a line-field interferometer integrated with an air-pulse delivery system. The propagation of the air-pulse induced elastic wave was imaged in real time, and required a single excitation for a line-scan measurement. Results on tissue-mimicking phantoms and chicken breast muscle demonstrated the feasibility of this technique for accurate assessment of tissue biomechanical properties with an acquisition time of a few milliseconds using parallel acquisition. PMID:27570694

  6. Single-shot fluctuations in waveguided high-harmonic generation.

    PubMed

    Goh, S J; Tao, Y; van der Slot, P J M; Bastiaens, H J M; Herek, J; Biedron, S G; Danailov, M B; Milton, S V; Boller, K-J

    2015-09-21

    For exploring the application potential of coherent soft x-ray (SXR) and extreme ultraviolet radiation (XUV) provided by high-harmonic generation, it is important to characterize the central output parameters. Of specific importance are pulse-to-pulse (shot-to-shot) fluctuations of the high-harmonic output energy, fluctuations of the direction of the emission (pointing instabilities), and fluctuations of the beam divergence and shape that reduce the spatial coherence. We present the first single-shot measurements of waveguided high-harmonic generation in a waveguided (capillary-based) geometry. Using a capillary waveguide filled with Argon gas as the nonlinear medium, we provide the first characterization of shot-to-shot fluctuations of the pulse energy, of the divergence and of the beam pointing. We record the strength of these fluctuations vs. two basic input parameters, which are the drive laser pulse energy and the gas pressure in the capillary waveguide. In correlation measurements between single-shot drive laser beam profiles and single-shot high-harmonic beam profiles we prove the absence of drive laser beam-pointing-induced fluctuations in the high-harmonic output. We attribute the main source of high-harmonic fluctuations to ionization-induced nonlinear mode mixing during propagation of the drive laser pulse inside the capillary waveguide. PMID:26406689

  7. Optimization of a single-shot EPI sequence for diffusion imaging of the human spinal cord

    NASA Astrophysics Data System (ADS)

    Rossi, Cristina; Boss, Andreas; Steidle, Guenter; Martirosian, Petros; Klose, Uwe; Capuani, Silvia; Maraviglia, Bruno; Claussen, Claus D.; Schick, Fritz

    2007-03-01

    Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are established techniques of magnetic resonance widely used for the characterization of the cerebral tissue. Despite the successful application in the brain, diffusion-weighted single-shot echo-planar-imaging (EPI) of the spinal cord is hindered by the need for highly-resolved spatial encoding in an area of strong magnetic field inhomogeneities, and the shortness of transverse relaxation time. The major aim of this study was the optimization of a reliable single-shot EPI sequence for DTI of the spinal cord at 1.5T. Ten healthy volunteers participated in the study (mean age=28.4+/-3.1). A single-shot EPI sequence with double spinecho diffusion preparation and nominal in-plane resolution of 0.9x0.9mm2 was optimized with regard to cerebrospinal fluid artifacts, and contrast-to-noise ratio between gray matter (GM) and white matter (WM). The effective sequence resolution was evaluated on a phantom. A cardiac-pulse gated sequence with optimal matrix size (read x phase=64x32) and b-value (700s/mm2) allowed for the acquisition of highly-resolved images of the spinal cord (effective in-plane resolution=1.1mm). Preliminary results on two healthy volunteers showed that the butterfly-shaped GM is clearly recognizable in the reconstructed fractional anisotropy (FA) maps. Measured WM FA values were 0.698+/-0.076 and 0.756+/-0.046. No significant differences were found in the mean diffusivity computed in the WM as compared to the GM areas. Optimized spinal cord diffusion imaging provided promising preliminary results on healthy volunteers. The application of the proposed protocol in the assessment of neurological disorders may allow for improved characterization of healthy and impaired WM and GM.

  8. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface.

    PubMed

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-01-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging.

  9. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

    NASA Astrophysics Data System (ADS)

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-06-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging.

  10. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface.

    PubMed

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-01-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging. PMID:27246668

  11. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

    PubMed Central

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-01-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging. PMID:27246668

  12. Single-Shot Fault-Tolerant Quantum Error Correction

    NASA Astrophysics Data System (ADS)

    Bombín, Héctor

    2015-07-01

    Conventional quantum error correcting codes require multiple rounds of measurements to detect errors with enough confidence in fault-tolerant scenarios. Here, I show that for suitable topological codes, a single round of local measurements is enough. This feature is generic and is related to self-correction and confinement phenomena in the corresponding quantum Hamiltonian model. Three-dimensional gauge color codes exhibit this single-shot feature, which also applies to initialization and gauge fixing. Assuming the time for efficient classical computations to be negligible, this yields a topological fault-tolerant quantum computing scheme where all elementary logical operations can be performed in constant time.

  13. Single-shot afocal three-dimensional microscopy.

    PubMed

    Feldkhun, Daniel; Wagner, Kelvin H

    2016-08-01

    Fourier-basis agile structured illumination sensing (F-BASIS) employs acousto-optically synthesized moving interference patterns, sparse RF-encoded aperture synthesis, nonredundant spatiotemporal frequency multiplexing, and single-pixel detection to measure dense clouds of three-dimensional (3D) Fourier samples without scanning, enabling high-speed focus-free volume microscopy. We present 3D fluorescence imaging results using F-BASIS, including an unprecedented wide-field single-shot volumetric measurement in under 10 ms. The unique capabilities provided by F-BASIS could prove instrumental for capturing fleeting dynamic processes such as neuron signaling in 3D.

  14. Single-shot afocal three-dimensional microscopy.

    PubMed

    Feldkhun, Daniel; Wagner, Kelvin H

    2016-08-01

    Fourier-basis agile structured illumination sensing (F-BASIS) employs acousto-optically synthesized moving interference patterns, sparse RF-encoded aperture synthesis, nonredundant spatiotemporal frequency multiplexing, and single-pixel detection to measure dense clouds of three-dimensional (3D) Fourier samples without scanning, enabling high-speed focus-free volume microscopy. We present 3D fluorescence imaging results using F-BASIS, including an unprecedented wide-field single-shot volumetric measurement in under 10 ms. The unique capabilities provided by F-BASIS could prove instrumental for capturing fleeting dynamic processes such as neuron signaling in 3D. PMID:27472599

  15. Image/video encryption using single shot digital holography

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyu; Tang, Chen; Zhu, Xinjun; Li, Biyuan; Wang, Linlin; Yan, Xiusheng

    2015-05-01

    We propose a method for image/video encryption that combines double random-phase encoding in the Fresnel domain with a single shot digital holography. In this method, a complex object field can be reconstructed with only single frame hologram based on a constrained optimization method. The system without multiple shots and Fourier lens is simple, and allows to dynamically encrypt information. We test the proposed method on a computer simulated image, a grayscale image and a video in AVI format. Also we investigate the quality of the decryption process and the performance against noise attacks. The experimental results demonstrate the performance of the method.

  16. Single-shot detection of bacterial endospores via coherent Raman spectroscopy

    PubMed Central

    Pestov, Dmitry; Wang, Xi; Ariunbold, Gombojav O.; Murawski, Robert K.; Sautenkov, Vladimir A.; Dogariu, Arthur; Sokolov, Alexei V.; Scully, Marlan O.

    2008-01-01

    Recent advances in coherent Raman spectroscopy hold exciting promise for many potential applications. For example, a technique, mitigating the nonresonant four-wave-mixing noise while maximizing the Raman-resonant signal, has been developed and applied to the problem of real-time detection of bacterial endospores. After a brief review of the technique essentials, we show how extensions of our earlier experimental work [Pestov D, et al. (2007) Science 316:265–268] yield single-shot identification of a small sample of Bacillus subtilis endospores (≈104 spores). The results convey the utility of the technique and its potential for “on-the-fly” detection of biohazards, such as Bacillus anthracis. The application of optimized coherent anti-Stokes Raman scattering scheme to problems requiring chemical specificity and short signal acquisition times is demonstrated. PMID:18184801

  17. In vivo single-shot 13C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding

    PubMed Central

    Schmidt, Rita; Laustsen, Christoffer; Dumez, Jean-Nicolas; Kettunen, Mikko I.; Serrao, Eva M.; Marco-Rius, Irene; Brindle, Kevin M.; Ardenkjaer-Larsen, Jan Henrik; Frydman, Lucio

    2016-01-01

    Hyperpolarized metabolic imaging is a growing field that has provided a tool for analyzing metabolism, particularly in cancer. Given the short life times of the hyperpolarized signal, fast and effective spectroscopic imaging methods compatible with dynamic metabolic characterizations are necessary. Several approaches have been customized for hyperpolarized 13C MRI, including CSI with a center-out k-space encoding, EPSI, and spectrally selective pulses in combination with spiral EPI acquisitions. Recent studies have described the potential of single-shot alternatives based on spatiotemporal encoding (SPEN) principles, to derive chemical-shift images within a sub-second period. By contrast to EPSI, SPEN does not require oscillating acquisition gradients to deliver chemical-shift information: its signal encodes both spatial as well as chemical shift information, at no extra cost in experimental complexity. SPEN MRI sequences with slice-selection and arbitrary excitation pulses can also be devised, endowing SPEN with the potential to deliver single-shot multi-slice chemical shift images, with a temporal resolution required for hyperpolarized dynamic metabolic imaging. The present work demonstrates this with initial in vivo results obtained from SPEN-based imaging of pyruvate and its metabolic products, after injection of hyperpolarized [1-13C]pyruvate. Multi-slice chemical-shift images of healthy rats were obtained at 4.7 T in the region of the kidney, and 4D (2D spatial, 1D spectral, 1D temporal) data sets were obtained at 7 T from a murine lymphoma tumor model. PMID:24486720

  18. In vivo single-shot 13C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding

    NASA Astrophysics Data System (ADS)

    Schmidt, Rita; Laustsen, Christoffer; Dumez, Jean-Nicolas; Kettunen, Mikko I.; Serrao, Eva M.; Marco-Rius, Irene; Brindle, Kevin M.; Ardenkjaer-Larsen, Jan Henrik; Frydman, Lucio

    2014-03-01

    Hyperpolarized metabolic imaging is a growing field that has provided a new tool for analyzing metabolism, particularly in cancer. Given the short life times of the hyperpolarized signal, fast and effective spectroscopic imaging methods compatible with dynamic metabolic characterizations are necessary. Several approaches have been customized for hyperpolarized 13C MRI, including CSI with a center-out k-space encoding, EPSI, and spectrally selective pulses in combination with spiral EPI acquisitions. Recent studies have described the potential of single-shot alternatives based on spatiotemporal encoding (SPEN) principles, to derive chemical-shift images within a sub-second period. By contrast to EPSI, SPEN does not require oscillating acquisition gradients to deliver chemical-shift information: its signal encodes both spatial as well as chemical shift information, at no extra cost in experimental complexity. SPEN MRI sequences with slice-selection and arbitrary excitation pulses can also be devised, endowing SPEN with the potential to deliver single-shot multi-slice chemical shift images, with a temporal resolution required for hyperpolarized dynamic metabolic imaging. The present work demonstrates this with initial in vivo results obtained from SPEN-based imaging of pyruvate and its metabolic products, after injection of hyperpolarized [1-13C]pyruvate. Multi-slice chemical-shift images of healthy rats were obtained at 4.7 T in the region of the kidney, and 4D (2D spatial, 1D spectral, 1D temporal) data sets were obtained at 7 T from a murine lymphoma tumor model.

  19. Single-shot ultrafast tomographic imaging by spectral multiplexing

    NASA Astrophysics Data System (ADS)

    Matlis, N. H.; Axley, A.; Leemans, W. P.

    2012-10-01

    Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

  20. Terahertz single-shot quadrature phase-shifting interferometry.

    PubMed

    Földesy, Péter

    2012-10-01

    A single-shot quadrature phase-shifting interferometry architecture is presented that is applicable to antenna coupled detector technologies. The method is based on orthogonally polarized object and reference beams and on linear and circular polarization sensitive antennas in space-division multiplexing. The technique can be adapted to two-, three-, and four-step and Gabor holography recordings. It is also demonstrated that the space-division multiplexing does not necessarily cause sparse sampling. A sub-THz detector array is presented containing multiple on-chip antennas and FET plasma wave detectors implemented in a 90 nm complementary metal-oxide semiconductor technology. As an example, two-step phase-shifting reconstruction results are given at 360 GHz. PMID:23027273

  1. Single-shot, optical-phase-insensitive interferometry with BECs

    NASA Astrophysics Data System (ADS)

    Griffin, Paul; Robertson, Billy; MacKellar, Andrew; Halket, James; Arnold, Aidan; Riis, Erling

    2016-05-01

    Atom interferometers allow the measurement of forces through detection of the differential phase shifts induced in the atomic wavefunction by the interaction. The atomic phase can then be readout against a lab-frame reference, typically the spatial phase of an optical standing wave. This readout is a leading limitation to practical measurement, requiring long temporal stability of the optical phase, without which the resolution of the atomic signal can be lost. We have built an atom interferometer that is inherently insensitive to the phase noise of the readout system. Here, we will describe new features developed in our Bose-Einstein condensate system, including tuneable, high-fidelity, symmetric atomic-beamsplitters through a multi-pulse Kapitza-Dirac scheme. We use an atomic homodyne detection that transfers the atomic phase into a temporal atomic beat-note, and show how the entire interferometric signal can be readout in a single shot. Results from the system include measurement of small-angle projection of the gravitational force, as well as the sensitivity of the atomic phase to gradients of magnetic fields.

  2. Single shot embedded surface plasmon microscopy with vortex illumination.

    PubMed

    Chow, Terry Wk; Pechprasarn, Suejit; Meng, JingKai; Somekh, Michael G

    2016-05-16

    In previous work we demonstrated how a confocal microscope with a spatial light modulator in the back focal plane could perform accurate measurement of the k-vector of a propagating surface plasmon. This involved forming an embedded interferometer between light incident close to normal incidence (reference beam) and light incident at the angle to excite surface plasmons (sample beam). The signal from the interferometer was extracted by stepping the phase of the reference beam relative to the sample beam using a spatial light modulator; this requires at least 3 phase steps, which limits the speed of operation. To overcome this and extract the same information with a single measurement, we project an azimuthal varying phase between 0 and 2π in the central region of the back focal plane; corresponding to small angles of incidence. This projects a vortex beam as the reference, so that the phase of the reference beam varies with azimuthal angle. By extracting the interference signal from different portions of the reference beam, different phase steps between the reference and the sample are obtained, so all the values required for phase reconstruction can be extracted simultaneously. It is thus possible to obtain the same information with a single shot measurement, at each defocus position, without additional changes to the back focal plane illumination. Results are presented to show that the vortex illuminated sample provides similar results to the phase stepped version, whose values are, in turn, validated with ellipsometry and surface profilometry. PMID:27409900

  3. Dual-wavelength digital holography: single shot calibration

    NASA Astrophysics Data System (ADS)

    Khodadad, Davood; Bergström, Per; Hällstig, Emil; Sjödahl, Mikael

    2014-07-01

    In an on line shape measurement in disturbed environment, use of many wavelengths in order to avoid phase ambiguity may become a problem as it is necessary to acquire all holograms simultaneously due to environmental disturbances. Therefore to make the shape data available the different holograms have to be extracted from a single recorded image in spectral domain. Appropriate cut areas in the Fourier method are therefore of great importance for decoding information carried by different wavelengths. Furthermore using different laser sources, induces aberration and pseudo phase changes which must be compensated. To insure any phase change is only because of the object shape, calibration is therefore indispensable. For this purpose, effects of uncontrolled carrier frequency filtering are discussed. A registration procedure is applied using minimum speckle displacements to find the best cut area to extract and match the interference terms. Both holograms are numerically propagated to a focus plane to avoid any unknown errors. Deviations between a reference known plate and its measurement are found and used for calibration. We demonstrate that phase maps and speckle displacements can be recovered free of chromatic aberrations. To our knowledge, this is the first time that a single shot dual wavelength calibration is reported by defining a criteria to make the spatial filtering automatic avoiding the problems of manual methods. The procedure is shown to give shape accuracy of 35μm with negligible systematic errors using a synthetic wavelength of 1.1 mm.

  4. Time-resolved single-shot terahertz time-domain spectroscopy for ultrafast irreversible processes

    NASA Astrophysics Data System (ADS)

    Zhai, Zhao-Hui; Zhong, Sen-Cheng; Li, Jun; Zhu, Li-Guo; Meng, Kun; Li, Jiang; Liu, Qiao; Peng, Qi-Xian; Li, Ze-Ren; Zhao, Jian-Heng

    2016-09-01

    Pulsed terahertz spectroscopy is suitable for spectroscopic diagnostics of ultrafast events. However, the study of irreversible or single shot ultrafast events requires ability to record transient properties at multiple time delays, i.e., time resolved at single shot level, which is not available currently. Here by angular multiplexing use of femtosecond laser pulses, we developed and demonstrated a time resolved, transient terahertz time domain spectroscopy technique, where burst mode THz pulses were generated and then detected in a single shot measurement manner. The burst mode THz pulses contain 2 sub-THz pulses, and the time gap between them is adjustable up to 1 ns with picosecond accuracy, thus it can be used to probe the single shot event at two different time delays. The system can detect the sub-THz pulses at 0.1 THz-2.5 THz range with signal to noise ratio (SNR) of ˜400 and spectrum resolution of 0.05 THz. System design was described here, and optimizations of single shot measurement of THz pulses were discussed in detail. Methods to improve SNR were also discussed in detail. A system application was demonstrated where pulsed THz signals at different time delays of the ultrafast process were successfully acquired within single shot measurement. This time resolved transient terahertz time domain spectroscopy technique provides a new diagnostic tool for irreversible or single shot ultrafast events where dynamic information can be extracted at terahertz range within one-shot experiment.

  5. Single-shot dual-polarization holography: measurement of the polarization state of a magnetic sample

    NASA Astrophysics Data System (ADS)

    Khodadad, Davood; Amer, Eynas; Gren, Per; Melander, Emil; Hällstig, Emil; Sjödahl, Mikael

    2015-08-01

    In this paper a single-shot digital holographic set-up with two orthogonally polarized reference beams is proposed to achieve rapid acquisition of Magneto-Optical Kerr Effect images. Principles of the method and the background theory for dynamic state of polarization measurement by use of digital holography are presented. This system has no mechanically moving elements or active elements for polarization control and modulation. An object beam is combined with two reference beams at different off-axis angles and is guided to a detector. Then two complex fields (interference terms) representing two orthogonal polarizations are recorded in a single frame simultaneously. Thereafter the complex fields are numerically reconstructed and carrier frequency calibration is done to remove aberrations introduced in multiplexed digital holographic recordings. From the numerical values of amplitude and phase, a real time quantitative analysis of the polarization state is possible by use of Jones vectors. The technique is demonstrated on a magnetic sample that is a lithographically patterned magnetic microstructure consisting of thin permalloy parallel stripes.

  6. Invited Article: Single-shot THz detection techniques optimized for multidimensional THz spectroscopy

    SciTech Connect

    Teo, Stephanie M.; Ofori-Okai, Benjamin K.; Werley, Christopher A.; Nelson, Keith A.

    2015-05-15

    Multidimensional spectroscopy at visible and infrared frequencies has opened a window into the transfer of energy and quantum coherences at ultrafast time scales. For these measurements to be performed in a manageable amount of time, one spectral axis is typically recorded in a single laser shot. An analogous rapid-scanning capability for THz measurements will unlock the multidimensional toolkit in this frequency range. Here, we first review the merits of existing single-shot THz schemes and discuss their potential in multidimensional THz spectroscopy. We then introduce improved experimental designs and noise suppression techniques for the two most promising methods: frequency-to-time encoding with linear spectral interferometry and angle-to-time encoding with dual echelons. Both methods, each using electro-optic detection in the linear regime, were able to reproduce the THz temporal waveform acquired with a traditional scanning delay line. Although spectral interferometry had mediocre performance in terms of signal-to-noise, the dual echelon method was easily implemented and achieved the same level of signal-to-noise as the scanning delay line in only 4.5% of the laser pulses otherwise required (or 22 times faster). This reduction in acquisition time will compress day-long scans to hours and hence provides a practical technique for multidimensional THz measurements.

  7. Single-shot temperature- and pressure-sensitive paint measurements on an unsteady helicopter blade

    NASA Astrophysics Data System (ADS)

    Disotell, Kevin J.; Peng, Di; Juliano, Thomas J.; Gregory, James W.; Crafton, Jim W.; Komerath, Narayanan M.

    2014-02-01

    Unsteady pressure-sensitive paint (PSP) measurements were acquired on an articulated model helicopter rotor of 0.26 m diameter in edgewise flow to simulate forward flight conditions. The rotor was operated at advance ratios (free stream velocity normalized by hover tip speed) of 0.15 and 0.30 at a cycle-averaged tip chord Reynolds number of 1.1 × 105, with collective and longitudinal cyclic pitch inputs of 10° and 2.5°, respectively. A single-shot data acquisition technique allowed a camera to record the paint luminescence after a single pulse of high-energy laser excitation, yielding sufficient signal-to-noise ratio to avoid image averaging. Platinum tetra(pentafluorophenyl) porphyrin (PtTFPP) in a porous polymer/ceramic binder served as the PSP. To address errors caused by image blurring and temperature sensitivity, a previously reported motion deblurring algorithm was implemented and the temperature correction was made using temperature-sensitive paint measurements on a second rotor blade. Instantaneous, unsteady surface pressure maps at a rotation rate of 82 Hz captured different aerodynamic responses between the two sides of the rotor disk and were compared to the nominally steady hover case. Cycle-to-cycle variations in tip unsteadiness on the retreating blade were also observed, causing oblique pressure features which may be linked to three-dimensional stall.

  8. Invited Article: Single-shot THz detection techniques optimized for multidimensional THz spectroscopy

    NASA Astrophysics Data System (ADS)

    Teo, Stephanie M.; Ofori-Okai, Benjamin K.; Werley, Christopher A.; Nelson, Keith A.

    2015-05-01

    Multidimensional spectroscopy at visible and infrared frequencies has opened a window into the transfer of energy and quantum coherences at ultrafast time scales. For these measurements to be performed in a manageable amount of time, one spectral axis is typically recorded in a single laser shot. An analogous rapid-scanning capability for THz measurements will unlock the multidimensional toolkit in this frequency range. Here, we first review the merits of existing single-shot THz schemes and discuss their potential in multidimensional THz spectroscopy. We then introduce improved experimental designs and noise suppression techniques for the two most promising methods: frequency-to-time encoding with linear spectral interferometry and angle-to-time encoding with dual echelons. Both methods, each using electro-optic detection in the linear regime, were able to reproduce the THz temporal waveform acquired with a traditional scanning delay line. Although spectral interferometry had mediocre performance in terms of signal-to-noise, the dual echelon method was easily implemented and achieved the same level of signal-to-noise as the scanning delay line in only 4.5% of the laser pulses otherwise required (or 22 times faster). This reduction in acquisition time will compress day-long scans to hours and hence provides a practical technique for multidimensional THz measurements.

  9. 2D-Omnidirectional Hard-X-Ray Scattering Sensitivity in a Single Shot.

    PubMed

    Kagias, Matias; Wang, Zhentian; Villanueva-Perez, Pablo; Jefimovs, Konstantins; Stampanoni, Marco

    2016-03-01

    X-ray scattering imaging can provide complementary information to conventional absorption based radiographic imaging about the unresolved microstructures of a sample. The scattering signal can be accessed with various methods based on coherent illumination, which span from self-imaging to speckle scanning. The directional sensitivity of the existing real space imaging methods is limited to a few directions on the imaging plane and requires scanning of the optical components, or the rotation of either the sample or the imaging setup, in order to cover the full range of possible scattering directions. In this Letter the authors propose a new method that allows the simultaneous acquisition of scattering images in all possible directions in a single shot. This is achieved by a specialized phase grating and a detector with sufficient spatial resolution to record the generated interference fringe. The structural length scale sensitivity of the system can be tuned by varying its geometry for a fixed grating design. Taking into account ongoing developments in the field of compact x-ray sources that allow high brightness and sufficient spatial coherence, the applicability of omnidirectional scattering imaging in industrial and medical settings is boosted significantly. PMID:26991177

  10. Towards Single-Shot Detection of Bacterial Endospores via Coherent Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pestov, Dmitry; Wang, Xi; Ariunbold, Gombojav; Murawski, Robert; Sautenkov, Vladimir; Sokolov, Alexei; Scully, Marlan

    2007-10-01

    Recent advances in coherent anti-Stokes Raman scattering (CARS) spectroscopy hold exciting promise to make the most out of now readily available ultrafast laser sources. Techniques have been devised to mitigate the nonresonant four-wave-mixing in favor of informative Raman-resonant signal. In particular, a hybrid technique for CARS (see Science 316, 265 (2007)) brings together the advantages of coherent broadband pump-Stokes excitation of molecular vibrations and their time-delayed but frequency-resolved probing via a spectrally narrowed and shaped laser pulse. We apply this technique to the problem of real-time detection of warfare bioagents and report single-shot acquisition of a distinct CARS spectrum from a small volume of B. subtilis endospores (˜10^4 spores), a harmless surrogate for B. anthracis. We study the dependence of the CARS signal on the energy of the ultrashort preparation pulses and find the limit on the pulse energy fluence (˜0.2 J/cm^2), imposed by the laser-induced damage of the spores.

  11. Variable density sampling and non-Cartesian super-resolved reconstruction for spatiotemporally encoded single-shot MRI

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Huang, Jianpan; Zhang, Ting; Li, Jing; Cai, Congbo; Cai, Shuhui

    2016-11-01

    Spatiotemporally encoded (SPEN) single-shot MRI is an emerging ultrafast technique, which is capable of spatially selective acquisition and reduced field-of-view imaging. Compared to uniform sampling, variable density sampling has great potential in reducing aliasing artifacts and improving sampling efficiency. In this study, variable density spiral trajectory and non-Cartesian super-resolved (SR) reconstruction method are developed for SPEN MRI. The gradient waveforms design of spiral trajectory is mathematically described as an optimization problem subjected to the limitations of hardware. Non-Cartesian SR reconstruction with specific gridding method is developed to retrieve a resolution enhanced image from raw SPEN data. The robustness and efficiency of the proposed methods are demonstrated by numerical simulation and various experiments. The results indicate that variable density SPEN MRI can provide better spatial resolution and fewer aliasing artifacts compared to Cartesian counterpart. The proposed methods will facilitate the development of variable density SPEN MRI.

  12. Single-shot compressed ultrafast photography at one hundred billion frames per second.

    PubMed

    Gao, Liang; Liang, Jinyang; Li, Chiye; Wang, Lihong V

    2014-12-01

    The capture of transient scenes at high imaging speed has been long sought by photographers, with early examples being the well known recording in 1878 of a horse in motion and the 1887 photograph of a supersonic bullet. However, not until the late twentieth century were breakthroughs achieved in demonstrating ultrahigh-speed imaging (more than 10(5) frames per second). In particular, the introduction of electronic imaging sensors based on the charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology revolutionized high-speed photography, enabling acquisition rates of up to 10(7) frames per second. Despite these sensors' widespread impact, further increasing frame rates using CCD or CMOS technology is fundamentally limited by their on-chip storage and electronic readout speed. Here we demonstrate a two-dimensional dynamic imaging technique, compressed ultrafast photography (CUP), which can capture non-repetitive time-evolving events at up to 10(11) frames per second. Compared with existing ultrafast imaging techniques, CUP has the prominent advantage of measuring an x-y-t (x, y, spatial coordinates; t, time) scene with a single camera snapshot, thereby allowing observation of transient events with temporal resolution as tens of picoseconds. Furthermore, akin to traditional photography, CUP is receive-only, and so does not need the specialized active illumination required by other single-shot ultrafast imagers. As a result, CUP can image a variety of luminescent--such as fluorescent or bioluminescent--objects. Using CUP, we visualize four fundamental physical phenomena with single laser shots only: laser pulse reflection and refraction, photon racing in two media, and faster-than-light propagation of non-information (that is, motion that appears faster than the speed of light but cannot convey information). Given CUP's capability, we expect it to find widespread applications in both fundamental and applied sciences, including

  13. Single-shot compressed ultrafast photography at one hundred billion frames per second

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Liang, Jinyang; Li, Chiye; Wang, Lihong V.

    2014-12-01

    The capture of transient scenes at high imaging speed has been long sought by photographers, with early examples being the well known recording in 1878 of a horse in motion and the 1887 photograph of a supersonic bullet. However, not until the late twentieth century were breakthroughs achieved in demonstrating ultrahigh-speed imaging (more than 105 frames per second). In particular, the introduction of electronic imaging sensors based on the charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology revolutionized high-speed photography, enabling acquisition rates of up to 107 frames per second. Despite these sensors' widespread impact, further increasing frame rates using CCD or CMOS technology is fundamentally limited by their on-chip storage and electronic readout speed. Here we demonstrate a two-dimensional dynamic imaging technique, compressed ultrafast photography (CUP), which can capture non-repetitive time-evolving events at up to 1011 frames per second. Compared with existing ultrafast imaging techniques, CUP has the prominent advantage of measuring an x-y-t (x, y, spatial coordinates; t, time) scene with a single camera snapshot, thereby allowing observation of transient events with temporal resolution as tens of picoseconds. Furthermore, akin to traditional photography, CUP is receive-only, and so does not need the specialized active illumination required by other single-shot ultrafast imagers. As a result, CUP can image a variety of luminescent--such as fluorescent or bioluminescent--objects. Using CUP, we visualize four fundamental physical phenomena with single laser shots only: laser pulse reflection and refraction, photon racing in two media, and faster-than-light propagation of non-information (that is, motion that appears faster than the speed of light but cannot convey information). Given CUP's capability, we expect it to find widespread applications in both fundamental and applied sciences, including biomedical

  14. Single-shot velocity-map imaging of attosecond light-field control at kilohertz rate

    NASA Astrophysics Data System (ADS)

    Süßmann, F.; Zherebtsov, S.; Plenge, J.; Johnson, Nora G.; Kübel, M.; Sayler, A. M.; Mondes, V.; Graf, C.; Rühl, E.; Paulus, G. G.; Schmischke, D.; Swrschek, P.; Kling, M. F.

    2011-09-01

    High-speed, single-shot velocity-map imaging (VMI) is combined with carrier-envelope phase (CEP) tagging by a single-shot stereographic above-threshold ionization (ATI) phase-meter. The experimental setup provides a versatile tool for angle-resolved studies of the attosecond control of electrons in atoms, molecules, and nanostructures. Single-shot VMI at kHz repetition rate is realized with a highly sensitive megapixel complementary metal-oxide semiconductor camera omitting the need for additional image intensifiers. The developed camera software allows for efficient background suppression and the storage of up to 1024 events for each image in real time. The approach is demonstrated by measuring the CEP-dependence of the electron emission from ATI of Xe in strong (≈1013 W/cm2) near single-cycle (4 fs) laser fields. Efficient background signal suppression with the system is illustrated for the electron emission from SiO2 nanospheres.

  15. Quantitative phase imaging by single-shot Hilbert-Huang phase microscopy.

    PubMed

    Trusiak, Maciej; Mico, Vicente; Garcia, Javier; Patorski, Krzysztof

    2016-09-15

    We propose a novel single-shot Hilbert-Huang transform-based algorithm applied to digital holographic microscopy (DHM) for robust, fast, and accurate single-shot quantitative phase imaging in on-axis and off-axis configurations. Fringe pattern with possible defects and closed fringes are adaptively filtered and accurately phase demodulated using local fringe direction estimation. Experimental validation of the proposed techniques is presented as the DHM study of microbeads and red blood cells phase samples. Obtained results compare very favorably with the Fourier approach (off-axis) and temporal phase shifting (on-axis). PMID:27628393

  16. Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns.

    PubMed

    Loh, N D; Bogan, M J; Elser, V; Barty, A; Boutet, S; Bajt, S; Hajdu, J; Ekeberg, T; Maia, F R N C; Schulz, J; Seibert, M M; Iwan, B; Timneanu, N; Marchesini, S; Schlichting, I; Shoeman, R L; Lomb, L; Frank, M; Liang, M; Chapman, H N

    2010-06-01

    We reconstructed the 3D Fourier intensity distribution of monodisperse prolate nanoparticles using single-shot 2D coherent diffraction patterns collected at DESY's FLASH facility when a bright, coherent, ultrafast x-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the expansion-maximization-compression framework to accommodate unmeasured fluctuations in photon fluence and loss of data due to saturation or background scatter. This work is an important step towards realizing single-shot diffraction imaging of single biomolecules.

  17. Cryptotomography: Reconstructing 3D Fourier Intensities from Randomly Oriented Single-Shot Diffraction Patterns

    NASA Astrophysics Data System (ADS)

    Loh, N. D.; Bogan, M. J.; Elser, V.; Barty, A.; Boutet, S.; Bajt, S.; Hajdu, J.; Ekeberg, T.; Maia, F. R. N. C.; Schulz, J.; Seibert, M. M.; Iwan, B.; Timneanu, N.; Marchesini, S.; Schlichting, I.; Shoeman, R. L.; Lomb, L.; Frank, M.; Liang, M.; Chapman, H. N.

    2010-06-01

    We reconstructed the 3D Fourier intensity distribution of monodisperse prolate nanoparticles using single-shot 2D coherent diffraction patterns collected at DESY’s FLASH facility when a bright, coherent, ultrafast x-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the expansion-maximization-compression framework to accommodate unmeasured fluctuations in photon fluence and loss of data due to saturation or background scatter. This work is an important step towards realizing single-shot diffraction imaging of single biomolecules.

  18. Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns.

    PubMed

    Loh, N D; Bogan, M J; Elser, V; Barty, A; Boutet, S; Bajt, S; Hajdu, J; Ekeberg, T; Maia, F R N C; Schulz, J; Seibert, M M; Iwan, B; Timneanu, N; Marchesini, S; Schlichting, I; Shoeman, R L; Lomb, L; Frank, M; Liang, M; Chapman, H N

    2010-06-01

    We reconstructed the 3D Fourier intensity distribution of monodisperse prolate nanoparticles using single-shot 2D coherent diffraction patterns collected at DESY's FLASH facility when a bright, coherent, ultrafast x-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the expansion-maximization-compression framework to accommodate unmeasured fluctuations in photon fluence and loss of data due to saturation or background scatter. This work is an important step towards realizing single-shot diffraction imaging of single biomolecules. PMID:20867179

  19. Single Shot Spinal Anaesthesia for Caesarean Delivery of Two Achondroplasic Parturients.

    PubMed

    İnan, Gözde; Yayla, Elif; Taş, Ünal; Arık, Esma; Günaydın, Berrin

    2015-08-01

    Because of structural defects in achondroplasia, as one of the dwarfism types, the choice of an anaesthetic technique and management for caesarean delivery presents a challenge. We aimed to discuss our successful single-shot spinal anaesthesia approach for caesarean section for one urgent and one elective achondroplasic parturient based on the literature. PMID:27366513

  20. Single-shot three-dimensional imaging of dilute atomic clouds.

    PubMed

    Sakmann, Kaspar; Kasevich, Mark

    2014-09-15

    Light field microscopy methods together with three-dimensional (3D) deconvolution can be used to obtain single-shot 3D images of atomic clouds. We demonstrate the method using a test setup that extracts 3D images from a fluorescent Rb87 atomic vapor. PMID:26466260

  1. Single-shot three-dimensional imaging of dilute atomic clouds.

    PubMed

    Sakmann, Kaspar; Kasevich, Mark

    2014-09-15

    Light field microscopy methods together with three-dimensional (3D) deconvolution can be used to obtain single-shot 3D images of atomic clouds. We demonstrate the method using a test setup that extracts 3D images from a fluorescent Rb87 atomic vapor.

  2. Broadband pump-probe imaging spectroscopy applicable to ultrafast single-shot events

    NASA Astrophysics Data System (ADS)

    Minami, Yasuo; Yamaki, Hiromoto; Katayama, Ikufumi; Takeda, Jun

    2014-02-01

    We propose a scheme for frequency-resolved single-shot spectroscopy with an echelon mirror. The echelon mirror is employed to generate spatially encoded time delays for the white-light continuum probe beam; it produces a temporal step of 66 fs and an overall time delay of 33 ps. We demonstrate broadband pump-probe imaging spectroscopy and present time-frequency two-dimensional images of the transient absorption of β-carotene between 420 and 630 nm with single-shot detection. The results show that this technique is a powerful tool for observing the ultrafast, broadband transient dynamics of materials that exhibit irreversible reactions or deterioration by laser pulse irradiation.

  3. Single-Shot Rotational Raman Thermometry for Turbulent Flames Using a Low-Resolution Bandwidth Technique

    NASA Technical Reports Server (NTRS)

    Kojima, Jun; Nguyen, Quang-Viet

    2007-01-01

    An alternative optical thermometry technique that utilizes the low-resolution (order 10(exp 1)/cm) pure-rotational spontaneous Raman scattering of air is developed to aid single-shot multiscalar measurements in turbulent combustion studies. Temperature measurements are realized by correlating the measured envelope bandwidth of the pure-rotational manifold of the N2/O2 spectrum with a theoretical prediction of a species-weighted bandwidth. By coupling this thermometry technique with conventional vibrational Raman scattering for species determination, we demonstrate quantitative spatially resolved, single-shot measurements of the temperature and fuel/oxidizer concentrations in a high-pressure turbulent Cf4-air flame. Our technique provides not only an effective means of validating other temperature measurement methods, but also serves as a secondary thermometry technique in cases where the anti-Stokes vibrational N2 Raman signals are too low for a conventional vibrational temperature analysis.

  4. Detection of the spatiotemporal field of a single-shot terahertz pulse based on spectral holography

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Lei; Fei, Yang; Li, Lu-Jie; Wang, Qiang; Zhu, Zhu-Qing

    2014-06-01

    According to electro-optical sampling theory, we propose a new method to detect the spatiotemporal field of a single-shot terahertz pulse by spectral holography for the first time. The single-shot terahertz pulse is coupled into a broadened chirped femtosecond pulse according to electro-optical sampling theory in the detecting system. Then the reference wave and the signal wave are split by Dammann grating and spread into the interference band-pass filter. The filtered sub-waves are at different central-frequencies because of the different incident angles. These sub-waves at different central-frequencies interfere to form sub-holograms, which are recorded in a single frame of a charge coupled device (CCD). The sub-holograms are numerically processed, and the spatiotemporal field distribution of the original terahertz pulse is reconstructed. The computer simulations verify the feasibility of the proposed method.

  5. Frequency-domain single-shot optical frequency comb tomography using VIPA

    NASA Astrophysics Data System (ADS)

    Miyaoka, Takumi; Shioda, Tatsutoshi

    2016-03-01

    Novel two-dimensional single-shot imaging optical system based on Frequency-domain interferometry using a virtually imaged phased array is proposed. The VIPA simultaneously outputs incoherent optical frequency combs (OFCs) whose teeth interval are scanned as a function of its output angle. Teeth intervals of the OFCs only in a reference are spatially swept by using of a VIPA whose advantage compared to an optical resonator. Thus, the single-shot imaging system can be realized with the FSR scanned frequency-domain OFC interference monitored by CCD. This system enable high speed 2-dimensional tomographic image without mechanical moving part. And the axial measurement range is not limited by using multi-order interference that is generated by OFCs interferometry. We will present the operation principle with its confirmed results in terms of both simulation and experiment.

  6. Single-shot optical readout of a quantum bit using cavity quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Sun, Shuo; Waks, Edo

    2016-07-01

    We propose a method to perform single-shot optical readout of a quantum bit (qubit) using cavity quantum electrodynamics. We selectively couple the optical transitions associated with different qubit basis states to the cavity and utilize the change in cavity transmissivity to generate a qubit readout signal composed of many photons. We show that this approach enables single-shot optical readout even when the qubit does not have a good cycling transition, which is required for standard resonance fluorescence measurements. We calculate the probability that the measurement detects the correct qubit state using the example of a quantum-dot spin under various experimental conditions and demonstrate that it can exceed 0.99.

  7. Computed tomography with single-shot dual-energy sandwich detectors

    NASA Astrophysics Data System (ADS)

    Kim, Seung Ho; Youn, Hanbean; Kim, Daecheon; Kim, Dong Woon; Jeon, Hosang; Kim, Ho Kyung

    2016-03-01

    Single-shot dual-energy sandwich detector can produce sharp images because of subtraction of images from two sub-detector layers, which have different thick x-ray converters, of the sandwich detector. Inspired by this observation, the authors have developed a microtomography system with the sandwich detector in pursuit of high-resolution bone-enhanced small-animal imaging. The preliminary results show that the bone-enhanced images reconstructed with the subtracted projection data are better in visibility of bone details than the conventionally reconstructed images. In addition, the bone-enhanced images obtained from the sandwich detector are relatively immune to the artifacts caused by photon starvation. The microtomography with the single-shot dual-energy sandwich detector will be useful for the high-resolution bone imaging.

  8. Broadband Single-Shot Electron Spectrometer for GeV-Class Laser Plasma Based Accelerators

    SciTech Connect

    Nakamura, K.; Wan, W.; Ybarrolaza, N.; Syversrud, D.; Wallig, J.; Leemans, W.P.

    2008-05-01

    Laser-plasma-based accelerators can provide electrons over a broad energy range and/or with large momentum spread. The electron beam energy distribution can be controlled via accurate control of laser and plasma properties, and beams with energies ranging from'0.5 to 1000 MeV have been observed. Measuring these energy distributions in a single shot requires the use of a diagnostic with large momentum acceptance and, ideally, sufficient resolution to accurately measure energy spread in the case of narrow energy spread. Such a broadband single-shot electron magnetic spectrometer for GeV-class laser-plasma-based accelerators has been developed at Lawrence Berkeley National Laboratory. A detailed description of the hardware and the design concept is presented, as well as a performance evaluation of the spectrometer. The spectrometer covered electron beam energies raging from 0.01 to 1.1 GeV in a single shot, and enabled the simultaneous measurement of the laser properties at the exit of the accelerator through the use of a sufficiently large pole gap. Based on measured field maps and 3rd-order transport analysis, a few percent-level resolution and determination of the absolute energy were achieved over the entire energy range. Laser-plasma-based accelerator experiments demonstrated the capability of the spectrometer as a diagnostic and its suitability for such a broadband electron source.

  9. Colliding pulse mode-locked lasers as light sources for single-shot holography

    NASA Astrophysics Data System (ADS)

    Grosse, Doris; Koukourakis, Nektarios; Gerhardt, Nils C.; Schlauch, Tobias; Balzer, Jan C.; Klehr, Andreas; Erbert, Götz; Tränkle, Günther; Hofmann, Martin R.

    2011-05-01

    So far, concepts for three dimensional biomedical imaging rely on scanning in at least one dimension. Single-shot holography1, in contrast, stores three-dimensional information encoded in an electro-magnetic wave scattered back from a sample in one single hologram. Single-shot holography operates with simultaneous recordings of holograms at different wavelengths. While the lateral sample information is stored in the interference patterns of individual holograms, the depth information is obtained from the spectral distribution at each lateral image point, similar to Fourier-domain optical coherence tomography2. Consequently, the depth resolution of the reconstructed image is determined by the bandwidth of the light source, so that a broadband light source is needed to obtain high depth resolution. Additionally, the holographic material, in which the holograms are stored, restricts the useable bandwidth. A thick photorefractive crystal can store several holograms of different wavelengths at once. As the crystal works best when using a source with a discrete spectrum, a light source is needed that has a spectrum with well distinguishable laser lines. In a proof-of-principle experiment, we use colliding pulse mode-locked (CPM)3 laser diodes as light sources with a comb-like spectrum to demonstrate the concept of single-shot holography by storing multiple holograms at the same time in a photorefractive Rh:BaTiO3 crystal.

  10. Single-shot electron bunch length measurements using a spatial electro-optical autocorrelation interferometer

    NASA Astrophysics Data System (ADS)

    Sütterlin, Daniel; Erni, Daniel; Schlott, Volker; Sigg, Hans; Jäckel, Heinz; Murk, Axel

    2010-10-01

    A spatial, electro-optical autocorrelation (EOA) interferometer using the vertically polarized lobes of coherent transition radiation (CTR) has been developed as a single-shot electron bunch length monitor at an optical beam port downstream the 100 MeV preinjector LINAC of the Swiss Light Source. This EOA monitor combines the advantages of step-scan interferometers (high temporal resolution) [D. Mihalcea et al., Phys. Rev. ST Accel. Beams 9, 082801 (2006) and T. Takahashi and K. Takami, Infrared Phys. Technol. 51, 363 (2008)] and terahertz-gating technologies [U. Schmidhammer et al., Appl. Phys. B: Lasers Opt. 94, 95 (2009) and B. Steffen et al., Phys. Rev. ST Accel. Beams 12, 032802 (2009)] (fast response), providing the possibility to tune the accelerator with an online bunch length diagnostics. While a proof of principle of the spatial interferometer was achieved by step-scan measurements with far-infrared detectors, the single-shot capability of the monitor has been demonstrated by electro-optical correlation of the spatial CTR interference pattern with fairly long (500 ps) neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pulses in a ZnTe crystal. In single-shot operation, variations of the bunch length between 1.5 and 4 ps due to different phase settings of the LINAC bunching cavities have been measured with subpicosecond time resolution.

  11. HyperSPASM NMR: A New Approach to Single-Shot 2D Correlations on DNP-Enhanced Samples

    PubMed Central

    Donovan, Kevin J.; Frydman, Lucio

    2016-01-01

    Dissolution DNP experiments are limited to a single or at most a few scan, before the non-Boltzmann magnetization has been. This makes it impractical to record 2D NMR data by conventional, t1-incremented schemes. Here a new approach termed HyperSPASM to establish 2D heteronuclear correlations in a single scan is reported, aimed at dealing with this kind of challenge. The HyperSPASM experiment relies on imposing an amplitude-modulation of the data by a single Δt1 indirect-domain evolution time, and subsequently monitoring the imparted encoding on separate echo and the anti-echo pathway signals within a single continuous acquisition. This is implemented via the use of alternating, switching, coherence selection gradients. As a result of these manipulations the phase imparted by a heteronucleus over its indirect domain evolution can be accurately extracted, and 2D data unambiguously reconstructed with a single-shot excitation. The nature of this sequence makes the resulting experiment particularly well suited for the collecting indirectly-detected HSQC data on hyperpolarized samples. The potential of the ensuing “HyperSPASM” method is exemplified with natural-abundance hyperpolarized correlations on model systems. PMID:23159821

  12. Single-shot digital holographic interferometry using a high power pulsed laser for full field measurement of traveling waves

    NASA Astrophysics Data System (ADS)

    De Greef, Daniël; Dirckx, Joris J. J.

    2012-06-01

    In the past, interferometric holographic techniques have been used extensively to perform full-field, yet timeaveraged analysis of vibrational patterns. When time-resolved information was needed, optical scanning single-point measurement techniques, such as heterodyne interferometric vibrometry, were available. Recently, stroboscopically illuminated digital holography has proven to yield both full-field and time-resolved information of vibrations with nanometer range amplitudes. In this technique, short laser pulses, synchronized to the vibration phase, are recorded. Good results have been achieved for high-frequency vibrations. However, due to the low energy in a single pulse, acquisition time increases for decreasing vibration frequency in order to receive enough energy on the camera, introducing problems such as artifacts due to slow movements of the object or electronic read-out noise. In this work, stroboscopic holography is combined with a high power, frequency doubled pulsed Nd:YAG laser, which produces enough energy in a single pulse to perform single-shot holographic recordings. This new setup allows imaging vibrations ranging from quasi-static deformations to high-frequency vibrations (1 - 20000 Hz), while avoiding the earlier mentioned acquisition issues. The additional challenge is to synchronize the lasers flash tube and Q-switch to the image acquisition and the vibration phase of the measured object. Results of measurements on a stretched circular latex membrane will be presented. The out-of-plane displacement of the membrane is visualized over the entire surface as a function of time, thus providing true four-dimensional information. Extracting the vibration phase map is useful, for instance to reveal travelling waves, which are invisible on time averaged images.

  13. Ultrahigh wavelength range (300nm-2μm) polarization-independent 500gs/s single-shot pulse, all-optical real time oscilloscope

    NASA Astrophysics Data System (ADS)

    Gleyze, Jean-François; Hocquet, Steve; Monnier Bourdin, Dominique; Le Boudec, Patrice; Arnaud, Romain; Chassagne, Bruno; Jolly, Alain; Penninckx, Denis

    2014-03-01

    The development of ultra-broadband oscilloscopes is mainly governed by the needs of future telecom networks. But other applications are requesting the availability of true real-time acquisition oscilloscopes. Systems able to be used in single-shot operation are of prime interest for Inertial Confinement Fusion (ICF) and for the related R&D for plasma physics. We previously demonstrate a single-shot, 100GHz design of an all-optical sampling oscilloscope at 1μm (MULO). This laboratory system has been improved in stability and compactness to make an all-in-one box prototype. More, by the addition of an opto-electro-optics (OEO) sub-system at the input, we developed the ability to use this oscilloscope to analyze an electrical input signal up to 60GHz. This new integrated subset also increases the range of wavelength for optical input signal, from 300nm up to 2μm. Furthermore, it allows the use of inexpensive opto-electronic components at telecom wavelength for this system regardless of the signal to be analysed. In parallel with these improvements, by optimizing the heart of the system, we get a very high sampling rate, up to 500Gs/s and more; this allows considering much higher bandwidths in the future. In this talk, we will present latest developments and integration of this system. It will also allow us to give more details on the innovative OEO sub-system.

  14. High-Dynamic-Range Single-Shot Cross-Correlator Based on an Optical Pulse Replicator

    SciTech Connect

    Dorrer, C.; Bromage, J.; Zuegel, J.D.

    2008-09-05

    The operation of a single-shot cross-correlator based on a pulse replicator is described. The correlator uses a discrete sequence of sampling pulses that are nonlinearly mixed with the pulse under test. The combination of a high reflector and partial reflector replicates an optical pulse by multiple internal reflections and generates a sequence of spatially displaced and temporally delayed sampling pulses. This principle is used in a cross-correlator characterizing optical pulses at 1053 nm. A dynamic range higher than 60 dB is obtained over a temporal range larger than 200 ps.

  15. Single shot, time-resolved measurement of the coherence properties of OCT swept source lasers.

    PubMed

    Butler, T; Slepneva, S; O'Shaughnessy, B; Kelleher, B; Goulding, D; Hegarty, S P; Lyu, H-C; Karnowski, K; Wojtkowski, M; Huyet, G

    2015-05-15

    A novel, time-resolved interferometric technique is presented that allows the reconstruction of the complex electric field output of a swept source laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography (OCT) applications with a spectral width of over 100 nm. The novel analysis allows a time-resolved real-time characterization of the roll-off, optical spectrum, linewidth, and coherence properties of a dynamic, rapidly swept laser source.

  16. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    SciTech Connect

    Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H.J.; Greaves, M.; Weber, C.P.; Falcone, R.W.; Padmore, H. A.; Heimann, P.A.

    2010-02-18

    An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.

  17. Single shot 3 GeV electron transverse emittance with a pepper-pot

    NASA Astrophysics Data System (ADS)

    Thomas, Cyrille; Delerue, Nicolas; Bartolini, Riccardo

    2013-11-01

    We present the first measurement of the transverse emittance of an electron bunch at 3 GeV using the pepper-pot technique. The measurements presented in this paper demonstrate the possibility to use such a method for single shot emittance measurement of high energy particles. This measurement presents also the experimental verification of a previous theoretical study, which was predicting in which condition such a measurement can be done. The method may present some technical limitations which are discussed in view of the application to future very small emittance multi-GeV particle accelerators.

  18. Single-shot spatiotemporal measurements of high-field terahertz pulses

    SciTech Connect

    van Tilborg, Jeroen; Schroeder, Carl; Toth, Csaba; Geddes, Cameron; Esarey, Eric; Leemans, Wim

    2011-06-17

    The electric field profiles of broad-bandwidth coherent terahertz (THz) pulses, emitted by laser-wakefield-accelerated electron bunches, are studied. The near-single-cycle THz pulses are measured with two single-shot techniques in the temporal and spatial domains. Spectra of 0-6 THz and peak fields up to {approx_equal} 0.4 MV cm{sup -1} are observed. The measured field substructure demonstrates the manifestation of spatiotemporal coupling at focus, which affects the interpretation of THz radiation as a bunch diagnostic and in high-field pump-probe experiments.

  19. Single-shot magnetic resonance spectroscopic imaging with partial parallel imaging.

    PubMed

    Posse, Stefan; Otazo, Ricardo; Tsai, Shang-Yueh; Yoshimoto, Akio Ernesto; Lin, Fa-Hsuan

    2009-03-01

    A magnetic resonance spectroscopic imaging (MRSI) pulse sequence based on proton-echo-planar-spectroscopic-imaging (PEPSI) is introduced that measures two-dimensional metabolite maps in a single excitation. Echo-planar spatial-spectral encoding was combined with interleaved phase encoding and parallel imaging using SENSE to reconstruct absorption mode spectra. The symmetrical k-space trajectory compensates phase errors due to convolution of spatial and spectral encoding. Single-shot MRSI at short TE was evaluated in phantoms and in vivo on a 3-T whole-body scanner equipped with a 12-channel array coil. Four-step interleaved phase encoding and fourfold SENSE acceleration were used to encode a 16 x 16 spatial matrix with a 390-Hz spectral width. Comparison with conventional PEPSI and PEPSI with fourfold SENSE acceleration demonstrated comparable sensitivity per unit time when taking into account g-factor-related noise increases and differences in sampling efficiency. LCModel fitting enabled quantification of inositol, choline, creatine, and N-acetyl-aspartate (NAA) in vivo with concentration values in the ranges measured with conventional PEPSI and SENSE-accelerated PEPSI. Cramer-Rao lower bounds were comparable to those obtained with conventional SENSE-accelerated PEPSI at the same voxel size and measurement time. This single-shot MRSI method is therefore suitable for applications that require high temporal resolution to monitor temporal dynamics or to reduce sensitivity to tissue movement.

  20. Direct single-shot phase retrieval from the diffraction pattern of separated objects

    DOE PAGES

    Leshem, Ben; Xu, Rui; Dallal, Yehonatan; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-02-22

    The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction’ experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing themore » phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Lastly, our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects.« less

  1. The LCLS variable-energy hard X-ray single-shot spectrometer.

    PubMed

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10(-5) or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

  2. Single-shot laser pulse reconstruction based on self-phase modulated spectra measurements.

    PubMed

    Anashkina, Elena A; Ginzburg, Vladislav N; Kochetkov, Anton A; Yakovlev, Ivan V; Kim, Arkady V; Khazanov, Efim A

    2016-01-01

    We report a method for ultrashort pulse reconstruction based only on the pulse spectrum and two self-phase modulated (SPM) spectra measured after pulse propagation through thin media with a Kerr nonlinearity. The advantage of this method is that it is a simple and very effective tool for characterization of complex signals. We have developed a new retrieval algorithm that was verified by reconstructing numerically generated fields, such as a complex electric field of double pulses and few-cycle pulses with noises, pedestals and dips down to zero spectral intensity, which is challenging for commonly used techniques. We have also demonstrated a single-shot implementation of the technique for the reconstruction of experimentally obtained pulses. This method can be used for high power laser systems operating in a single-shot mode in the optical, near- and mid-IR spectral ranges. The method is robust, low cost, stable to noise, does not require a priori information, and has no ambiguity related to time direction. PMID:27646027

  3. Single-shot time-resolved THz spectroscopy using non-collinear electro-optic imaging

    NASA Astrophysics Data System (ADS)

    Wang, Zhenyou; Su, Fuhai; Hegmann, Frank A.

    2010-03-01

    We demonstrate a technique for rapid substance identification via single-shot, coherent THz imaging using non-collinear electro-optic sampling. A THz probe pulse generated in ZnTe is transmitted through the sample then focused on a (110) ZnTe detection crystal. An 800nm, 100fs optical pulse employed as a sampling beam passes through the ZnTe detection crystal at an angle of 7^o relative to the THz beam.footnotetextT. Yasuda et al., Opt. Commun. 267, 128 (2006) The THz field induced birefringence is resolved as a variation of the intensity of the sampling pulse transmitted through a crossed polarizer. The modified sampling beam spot is imaged using a CCD camera. Because of the non-collinear geometry, the spatial overlap between the THz field and the optical pulse depends on the temporal position within the THz waveform. Consequently, we obtain high-resolution 2D images of the THz waveform without scanning the relative path length. The resolution of the absorption spectra extracted from wet paper and lactose using the single-shot imaging approach is comparable to the resolution obtained through conventional scanning lock-in measurements. Possible applications for substance detection are discussed.

  4. Single-shot, lifetime-based pressure-sensitive paint for rotating blades

    NASA Astrophysics Data System (ADS)

    Juliano, Thomas J.; Kumar, Pradeep; Peng, Di; Gregory, James W.; Crafton, Jim; Fonov, Sergey

    2011-08-01

    A single-shot, lifetime-based pressure-sensitive paint (PSP) technique is proposed as a pressure sensor for applications requiring high pressure sensitivity on a moving model such as a rotor blade. The method is based on a single pulse of high-energy excitation light and a double-frame exposure on an interline transfer charge-coupled device camera for recording luminescent lifetime. Small pressures can be measured on surfaces that are moving in an aperiodic manner (which precludes phase averaging). Measurements in environments having overall surface pressure gradients as small as 1 kPa show that the technique is capable of accurately resolving small pressure fluctuations. The pressure sensitivity to the oxygen concentration of some commonly available PSP formulations has been investigated with respect to capabilities and limitations of the paints for this single-shot lifetime application. A system with ruthenium-based pressure-sensitive paint, 532 nm wavelength laser and a CCD camera is demonstrated on a 0.126 m diameter propeller rotating at 70 Hz. Pressure data are acquired within a single pulse of excitation light energy, with no image averaging required.

  5. Single-shot volumetric laser induced fluorescence (VLIF) measurements in turbulent flows seeded with iodine.

    PubMed

    Wu, Yue; Xu, Wenjiang; Lei, Qingchun; Ma, Lin

    2015-12-28

    This work reports the experimental demonstration of single-shot visualization of turbulent flows in all three spatial dimensions (3D) based on volumetric laser induced fluorescence (VLIF). The measurements were performed based on the LIF signal of iodine (I2) vapor seeded in the flow. In contrast to established planar LIF (PLIF) technique, the VLIF technique excited the seeded I2 vapor volumetrically by a thick laser slab. The volumetric LIF signals emitted were then simultaneously collected by a total of five cameras from five different orientations, based on which a 3D tomographic reconstruction was performed to obtain the 3D distribution of the I2 vapor in the target flow. Single-shot measurements (with a measurement duration of a few ns) were demonstrated in a 50 mm × 50 mm × 50 mm volume with a nominal spatial resolution of 0.42 mm and an actual resolution of ~0.71 mm in all three dimensions (corresponding to a total of 120 × 120 × 120 voxels). PMID:26832005

  6. Single-shot laser pulse reconstruction based on self-phase modulated spectra measurements

    PubMed Central

    Anashkina, Elena A.; Ginzburg, Vladislav N.; Kochetkov, Anton A.; Yakovlev, Ivan V.; Kim, Arkady V.; Khazanov, Efim A.

    2016-01-01

    We report a method for ultrashort pulse reconstruction based only on the pulse spectrum and two self-phase modulated (SPM) spectra measured after pulse propagation through thin media with a Kerr nonlinearity. The advantage of this method is that it is a simple and very effective tool for characterization of complex signals. We have developed a new retrieval algorithm that was verified by reconstructing numerically generated fields, such as a complex electric field of double pulses and few-cycle pulses with noises, pedestals and dips down to zero spectral intensity, which is challenging for commonly used techniques. We have also demonstrated a single-shot implementation of the technique for the reconstruction of experimentally obtained pulses. This method can be used for high power laser systems operating in a single-shot mode in the optical, near- and mid-IR spectral ranges. The method is robust, low cost, stable to noise, does not require a priori information, and has no ambiguity related to time direction. PMID:27646027

  7. The LCLS variable-energy hard X-ray single-shot spectrometer

    SciTech Connect

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10-5or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

  8. The LCLS variable-energy hard X-ray single-shot spectrometer

    SciTech Connect

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10-5or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

  9. The LCLS variable-energy hard X-ray single-shot spectrometer.

    PubMed

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10(-5) or better. Those performance goals have all been achieved during the commissioning of the HXSSS. PMID:26698039

  10. Single-shot, high-resolution, fiber-based phase-diversity photodetection of optical pulses

    NASA Astrophysics Data System (ADS)

    Dorrer, C.; Waxer, L. J.; Kalb, A.; Hill, E. M.; Bromage, J.

    2016-03-01

    Temporally characterizing optical pulses is an important task when building, optimizing, and using optical sources. Direct photodetection with high-bandwidth photodiodes and real-time oscilloscopes is only adequate for optical pulses longer than ~10 ps; diagnostics based on indirect strategies are required to characterize femtosecond and sub-10-ps coherent sources. Most of these diagnostics are based on nonlinear optics and can be difficult to implement for the single-shot characterization of nonrepetitive events. A temporal diagnostic based on phase diversity is demonstrated in the context of picosecond high-energy laser systems, where single-shot pulse measurements are required for system safety and interpretation of experimental results. A plurality of ancillary optical pulses obtained by adding known amounts of chromatic dispersion to the pulse under test are directly measured by photodetection and processed to reconstruct the input pulse shape. This high-sensitivity (~50-pJ) diagnostic is based on a pulse replicator composed of fiber splitters and delay fibers, making it possible to operate with fiber sources and free-space sources after fiber coupling. Experimental data obtained with a high-bandwidth real-time oscilloscope demonstrate accurate characterization of pulses from a high-energy chirped-pulse amplification system, even for pulses shorter than the photodetection impulse response.

  11. Single-shot magnetic resonance spectroscopic imaging with partial parallel imaging.

    PubMed

    Posse, Stefan; Otazo, Ricardo; Tsai, Shang-Yueh; Yoshimoto, Akio Ernesto; Lin, Fa-Hsuan

    2009-03-01

    A magnetic resonance spectroscopic imaging (MRSI) pulse sequence based on proton-echo-planar-spectroscopic-imaging (PEPSI) is introduced that measures two-dimensional metabolite maps in a single excitation. Echo-planar spatial-spectral encoding was combined with interleaved phase encoding and parallel imaging using SENSE to reconstruct absorption mode spectra. The symmetrical k-space trajectory compensates phase errors due to convolution of spatial and spectral encoding. Single-shot MRSI at short TE was evaluated in phantoms and in vivo on a 3-T whole-body scanner equipped with a 12-channel array coil. Four-step interleaved phase encoding and fourfold SENSE acceleration were used to encode a 16 x 16 spatial matrix with a 390-Hz spectral width. Comparison with conventional PEPSI and PEPSI with fourfold SENSE acceleration demonstrated comparable sensitivity per unit time when taking into account g-factor-related noise increases and differences in sampling efficiency. LCModel fitting enabled quantification of inositol, choline, creatine, and N-acetyl-aspartate (NAA) in vivo with concentration values in the ranges measured with conventional PEPSI and SENSE-accelerated PEPSI. Cramer-Rao lower bounds were comparable to those obtained with conventional SENSE-accelerated PEPSI at the same voxel size and measurement time. This single-shot MRSI method is therefore suitable for applications that require high temporal resolution to monitor temporal dynamics or to reduce sensitivity to tissue movement. PMID:19097245

  12. Single-shot laser pulse reconstruction based on self-phase modulated spectra measurements

    NASA Astrophysics Data System (ADS)

    Anashkina, Elena A.; Ginzburg, Vladislav N.; Kochetkov, Anton A.; Yakovlev, Ivan V.; Kim, Arkady V.; Khazanov, Efim A.

    2016-09-01

    We report a method for ultrashort pulse reconstruction based only on the pulse spectrum and two self-phase modulated (SPM) spectra measured after pulse propagation through thin media with a Kerr nonlinearity. The advantage of this method is that it is a simple and very effective tool for characterization of complex signals. We have developed a new retrieval algorithm that was verified by reconstructing numerically generated fields, such as a complex electric field of double pulses and few-cycle pulses with noises, pedestals and dips down to zero spectral intensity, which is challenging for commonly used techniques. We have also demonstrated a single-shot implementation of the technique for the reconstruction of experimentally obtained pulses. This method can be used for high power laser systems operating in a single-shot mode in the optical, near- and mid-IR spectral ranges. The method is robust, low cost, stable to noise, does not require a priori information, and has no ambiguity related to time direction.

  13. Direct single-shot phase retrieval from the diffraction pattern of separated objects

    PubMed Central

    Leshem, Ben; Xu, Rui; Dallal, Yehonatan; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-01-01

    The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction' experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing the phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects. PMID:26899582

  14. Single-shot femtosecond x-ray diffraction from randomly oriented ellipsoidal nanoparticles

    NASA Astrophysics Data System (ADS)

    Bogan, M. J.; Boutet, S.; Barty, A.; Benner, W. H.; Frank, M.; Lomb, L.; Shoeman, R.; Starodub, D.; Seibert, M. M.; Hau-Riege, S. P.; Woods, B.; Decorwin-Martin, P.; Bajt, S.; Schulz, J.; Rohner, U.; Iwan, B.; Timneanu, N.; Marchesini, S.; Schlichting, I.; Hajdu, J.; Chapman, H. N.

    2010-09-01

    Coherent diffractive imaging of single particles using the single-shot “diffract and destroy” approach with an x-ray free electron laser (FEL) was recently demonstrated. A high-resolution low-noise coherent diffraction pattern, representative of the object before it turns into a plasma and explodes, results from the interaction of the FEL with the particle. Iterative phase retrieval algorithms are used to reconstruct two-dimensional projection images of the object from the recorded intensities alone. Here we describe the first single-shot diffraction data set that mimics the data proposed for obtaining 3D structure from identical particles. Ellipsoidal iron oxide nanoparticles (250nm×50nm) were aerosolized and injected through an aerodynamic lens stack into a soft x-ray FEL. Particle orientation was not controlled with this injection method. We observed that, at the instant the x-ray pulse interacts with the particle, a snapshot of the particle’s orientation is encoded in the diffraction pattern. The results give credence to one of the technical concepts of imaging individual nanometer and subnanometer-sized objects such as single molecules or larger clusters of molecules using hard x-ray FELs and will be used to help develop robust algorithms for determining particle orientations and 3D structure.

  15. Direct single-shot phase retrieval from the diffraction pattern of separated objects.

    PubMed

    Leshem, Ben; Xu, Rui; Dallal, Yehonatan; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-02-22

    The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called 'diffraction before destruction' experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing the phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects.

  16. Single-shot carrier-envelope-phase-tagged ion-momentum imaging of nonsequential double ionization of argon in intense 4-fs laser fields

    SciTech Connect

    Johnson, Nora G.; Herrwerth, O.; Wirth, A.; De, S.; Ben-Itzhak, I.; Lezius, M.; Bergues, B.; Kling, M. F.; Senftleben, A.; Schroeter, C. D.; Moshammer, R.; Ullrich, J.; Betsch, K. J.; Jones, R. R.; Sayler, A. M.; Rathje, T.; Ruehle, K.; Mueller, W.; Paulus, G. G.

    2011-01-15

    Single-shot carrier-envelope-phase (CEP) tagging is combined with a reaction mircoscope (REMI) to investigate CEP-dependent processes in atoms. Excellent experimental stability and data acquisition longevity are achieved. Using this approach, we study the CEP effects for nonsequential double ionization of argon in 4-fs laser fields at 750 nm and an intensity of 1.6x10{sup 14} W/cm{sup 2}. The Ar{sup 2+} ionization yield shows a pronounced CEP dependence which compares well with recent theoretical predictions employing quantitative rescattering theory [S. Micheau et al., Phys. Rev. A 79, 013417 (2009)]. Furthermore, we find strong CEP influences on the Ar{sup 2+} momentum spectra along the laser polarization axis.

  17. Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source

    SciTech Connect

    Ravasio, A.; Gauthier, D.; Billon, M.; Caumes, J-P.; Garzella, D.; Geleoc, M.; Gobert, O.; Hergott, J-F.; Pena, A-M.; Perez, H.; Carre, B.; Maia, F. R. N. C.; Bourhis, E.; Gierak, J.; Madouri, A.; Mailly, D.; Schiedt, B.; Fajardo, M.; Gautier, J.; Zeitoun, P.

    2009-07-10

    Coherent x-ray diffractive imaging is a powerful method for studies on nonperiodic structures on the nanoscale. Access to femtosecond dynamics in major physical, chemical, and biological processes requires single-shot diffraction data. Up to now, this has been limited to intense coherent pulses from a free electron laser. Here we show that laser-driven ultrashort x-ray sources offer a comparatively inexpensive alternative. We present measurements of single-shot diffraction patterns from isolated nano-objects with a single 20 fs pulse from a table-top high-harmonic x-ray laser. Images were reconstructed with a resolution of 119 nm from the single shot and 62 nm from multiple shots.

  18. Single-shot spatially modulated Stokes polarimeter based on a GRIN lens.

    PubMed

    Chang, Jintao; Zeng, Nan; He, Honghui; He, Yonghong; Ma, Hui

    2014-05-01

    A new polarimeter for the simultaneous measurement of all Stokes parameters in a single shot is presented. It consists of only a gradient index (GRIN) lens, a polarizer, an imaging lens, and a CCD, without mechanical movements, electrical signal modulation, or the division of amplitude components. This design takes advantage of the continuous spatial distributions of birefringence value and the fast axis direction of a GRIN lens and derives the state of polarization (SOP) of the incident beam from the characteristic patterns on the CCD images. Tests show that this polarimeter is very accurate even with low-resolution images. It is versatile and adapts to light sources of different wavelengths. It is also very stable, robust, low cost, and simple to use. PMID:24784070

  19. White light single-shot interferometry with colour CCD camera for optical inspection of microsystems

    NASA Astrophysics Data System (ADS)

    Upputuri, Paul Kumar; Pramanik, Manojit; Nandigana, Krishna Mohan; Kothiyal, Mahendra Prasad

    2015-07-01

    White light interferometry is a well-established optical tool for surface metrology of reflective samples. In this work, we discuss a single-shot white light interferometer based on single-chip color CCD camera and Hilbert transformation. The approach makes the measurement dynamic, faster, easier and cost-effective for industrial applications. Here we acquire only one white light interferogram using colour CCD camera and then decompose into its individual components using software. We present a simple Hilbert transformation approach to remove the non-uniform bias associated with the interference signal. The phases at individual wavelengths are calculated using Hilbert transformation. The use of Hilbert transformation introduces phase error which depends on number of fringe cycles. We discuss these errors. Experimental results on reflective micro-scale-samples for surface profiling are presented.

  20. Single-shot lamina thoracic paravertebral block with ketofol for modified radical mastectomy

    PubMed Central

    Rukewe, Ambrose; Afuwape, Oludolapo O; Ugheoke, Austin; Fatiregun, Akinola A

    2016-01-01

    We describe the use of single-shot lamina thoracic paravertebral block (TPVB) with sedation for a 56-year-old female patient who had modified radical mastectomy with axillary clearance. Two years ago, she suffered vocal cord palsy post thyroidectomy, which was managed with tracheostomy. The tracheostomy tube was removed 8 months later, leaving the patient with persistent hoarseness of voice and left vocal cord palsy. She declined general anesthesia and consented for TPVB. The surgery lasted 95 minutes and was successfully completed with TPVB. Her vital signs were stable during the operation. She had low pain scores, minimal opioid use, early alimentation, and no postoperative nausea and vomiting and was discharged early. We present the anesthetic management of this case in our setting, where TPVB under ultrasound guidance and modern drug-delivery systems for sedation are unavailable. PMID:27785098

  1. Single shot speckle and coherence analysis of the hard X-ray free electron laser LCLS.

    PubMed

    Lee, Sooheyong; Roseker, W; Gutt, C; Fischer, B; Conrad, H; Lehmkühler, F; Steinke, I; Zhu, D; Lemke, H; Cammarata, M; Fritz, D M; Wochner, P; Castro-Colin, M; Hruszkewycz, S O; Fuoss, P H; Stephenson, G B; Grübel, G; Robert, A

    2013-10-21

    The single shot based coherence properties of hard x-ray pulses from the Linac Coherent Light Source (LCLS) were measured by analyzing coherent diffraction patterns from nano-particles and gold nanopowder. The intensity histogram of the small angle x-ray scattering ring from nano-particles reveals the fully transversely coherent nature of the LCLS beam with a number of transverse mode 〈Ms〉 = 1.1. On the other hand, the speckle contrasts measured at a large wavevector yields information about the longitudinal coherence of the LCLS radiation after a silicon (111) monochromator. The quantitative agreement between our data and the simulation confirms a mean coherence time of 2.2 fs and a x-ray pulse duration of 29 fs. Finally the observed reduction of the speckle contrast generated by x-rays with pulse duration longer than 30 fs indicates ultrafast dynamics taking place at an atomic length scale prior to the permanent sample damage.

  2. High aspect ratio nanochannel machining using single shot femtosecond Bessel beams

    SciTech Connect

    Bhuyan, M. K.; Courvoisier, F.; Lacourt, P. A.; Jacquot, M.; Salut, R.; Furfaro, L.; Dudley, J. M.

    2010-08-23

    We report high aspect ratio nanochannel fabrication in glass using single-shot femtosecond Bessel beams of sub-3 {mu}J pulse energies at 800 nm. We obtain near-parallel nanochannels with diameters in the range 200-800 nm, and aspect ratios that can exceed 100. An array of 230 nm diameter channels with 1.6 {mu}m pitch illustrates the reproducibility of this approach and the potential for writing periodic structures. We also report proof-of-principle machining of a through-channel of 400 nm diameter in a 43 {mu}m thick membrane. These results represent a significant advance of femtosecond laser ablation technology into the nanometric regime.

  3. Compressive sensing sectional imaging for single-shot in-line self-interference incoherent holography

    NASA Astrophysics Data System (ADS)

    Weng, Jiawen; Clark, David C.; Kim, Myung K.

    2016-05-01

    A numerical reconstruction method based on compressive sensing (CS) for self-interference incoherent digital holography (SIDH) is proposed to achieve sectional imaging by single-shot in-line self-interference incoherent hologram. The sensing operator is built up based on the physical mechanism of SIDH according to CS theory, and a recovery algorithm is employed for image restoration. Numerical simulation and experimental studies employing LEDs as discrete point-sources and resolution targets as extended sources are performed to demonstrate the feasibility and validity of the method. The intensity distribution and the axial resolution along the propagation direction of SIDH by angular spectrum method (ASM) and by CS are discussed. The analysis result shows that compared to ASM the reconstruction by CS can improve the axial resolution of SIDH, and achieve sectional imaging. The proposed method may be useful to 3D analysis of dynamic systems.

  4. Single-shot stand-off chemical identification of powders using random Raman lasing.

    PubMed

    Hokr, Brett H; Bixler, Joel N; Noojin, Gary D; Thomas, Robert J; Rockwell, Benjamin A; Yakovlev, Vladislav V; Scully, Marlan O

    2014-08-26

    The task of identifying explosives, hazardous chemicals, and biological materials from a safe distance is the subject we consider. Much of the prior work on stand-off spectroscopy using light has been devoted to generating a backward-propagating beam of light that can be used drive further spectroscopic processes. The discovery of random lasing and, more recently, random Raman lasing provide a mechanism for remotely generating copious amounts of chemically specific Raman scattered light. The bright nature of random Raman lasing renders directionality unnecessary, allowing for the detection and identification of chemicals from large distances in real time. In this article, the single-shot remote identification of chemicals at kilometer-scale distances is experimentally demonstrated using random Raman lasing. PMID:25114231

  5. Single-shot measurement of the complete temporal intensity and phase of supercontinuum

    NASA Astrophysics Data System (ADS)

    Wong, Tsz Chun; Rhodes, Michelle; Trebino, Rick

    2016-03-01

    We solve the problem of single-shot complete temporal measurement of continuum using cross-correlation frequency-resolved optical gating, achieving the necessary large spectral range using a polarization-gating geometry and the necessary large temporal range by significantly tilting the reference pulse. In addition, we simultaneously cancel the previously unavoidable longitudinal geometrical temporal smearing by using a carefully chosen combination of pulse tilt and beam-crossing angle, thus simultaneously achieving the required temporal resolution. The result is that we are able to make a complete measurement of an individual complex continuum pulse generated in photonic-crystal fiber. By enabling measurement of single optical rogue waves, this technique could provide insight and perhaps even lead to the prediction of when mathematically similar, destructive, oceanic rogue waves may occur.

  6. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator.

    PubMed

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michaël; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W D; Wilson, C M; Delsing, Per; Bylander, Jonas

    2016-01-01

    We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing. PMID:27156732

  7. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    SciTech Connect

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  8. Single-shot electro-optic sampling of coherent transition radiation at the A0 Photoinjector

    SciTech Connect

    Maxwell, T.J.; Ruan, J.; Piot, P.; Thurman-Keup, R.; /Fermilab

    2011-08-01

    Future collider applications and present high-gradient laser plasma wakefield accelerators operating with picosecond bunch durations place a higher demand on the time resolution of bunch distribution diagnostics. This demand has led to significant advancements in the field of electro-optic sampling over the past ten years. These methods allow the probing of diagnostic light such as coherent transition radiation or the bunch wakefields with sub-picosecond time resolution. Potential applications in shot-to-shot, non-interceptive diagnostics continue to be pursued for live beam monitoring of collider and pump-probe experiments. Related to our developing work with electro-optic imaging, we present results on single-shot electro-optic sampling of the coherent transition radiation from bunches generated at the A0 photoinjector.

  9. Single-shot digital holography for fast measuring optical properties of fibers.

    PubMed

    Agour, Mostafa; El-Farahaty, Keremal; Seisa, Eman; Omar, Emam; Sokkar, Taha

    2015-10-01

    We propose a fast method for measuring optical properties, e.g., the refractive index profile and birefringence, of fibers. It is based on recovering the phase distribution of light refracted by a fiber sample at the recording plane from a single-shot digital hologram. During the recovering process, an optimized approach based on the spatial carrier frequency method was utilized. The proposed approach enhances affects that arise from the limited spatial extent of the bandpass filter associated with the implementation of the spatial carrier frequency method. In contrast to the low spatial resolution of off-axis digital holograms, the method ensures the best utilization of the camera support. From the recovered phase information, the optical path difference is measured; thus, the refractive index profile, the mean refractive index, and the birefringence of isotactic polypropylene (IPP) are determined. Experimental results are given for illustration. PMID:26479652

  10. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator

    PubMed Central

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michaël; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    2016-01-01

    We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing. PMID:27156732

  11. Single-shot measurements of plasmons in compressed diamond with an x-ray laser

    SciTech Connect

    Gamboa, E. J.; Fletcher, L. B.; Lee, H. J.; Galtier, E.; Gauthier, M.; Granados, E.; Hastings, J. B.; Glenzer, S. H.; Zastrau, U.; MacDonald, M. J.; Vorberger, J.; Gericke, D. O.

    2015-05-15

    Strong plasmon resonances characteristics of electron density fluctuations have recently been observed in dynamically compressed diamond for the first time at the Linac Coherent Light Source. These experiments observe the forward scattering spectra from 8 keV x-ray pulses at record peak brightness to probe laser-compressed diamond foils at the Matter in Extreme Conditions instrument. We demonstrate single-shot measurements of the x-ray scattering spectrum, which are sensitive to the temperatures and densities of the compressed samples. The inferred values from the inelastic scattering are compared to simulations, finding good agreement with the temperature and demonstrating the need to include solid state effects in the modeling of the plasmon oscillation.

  12. Single-shot electro-optic experiments for electron bunch diagnostics at Tsinghua Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Du, Yingchao; Yan, Lixin; Hua, Jianfei; Zhang, Zhen; Zhou, Zheng; Huang, Wenhui; Tang, Chuanxiang; Li, Ming

    2016-10-01

    The electro-optic (EO) technique detects the Coulomb electric field distribution of relativistic electron bunches to obtain the associated longitudinal profile. This diagnostic method allows the direct time-resolved single-shot measurement and thus the real-time monitoring of the bunch profile and beam arrival time in a non-destructive way with sub-picosecond temporal resolution. In this paper, we report the measurement of the longitudinal profile of an electron bunch through electro-optic spectral decoding detection, in which the bunch profile is encoded into the spectra of the linearly chirped laser pulse. The experimental setup and measurement results of a 40 MeV electron bunch are presented, with a temporal profile length of 527 fs rms (~1.24 ps FWHM) and a beam arrival time jitter of 471 fs rms. Temporal resolution and future experimental improvement are also discussed.

  13. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator

    NASA Astrophysics Data System (ADS)

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michaël; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    2016-05-01

    We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185+/-15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing.

  14. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser.

    PubMed

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-01-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources. PMID:26610328

  15. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  16. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser

    PubMed Central

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-01-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources. PMID:26610328

  17. An aliasing artifacts reducing approach with random undersampling for spatiotemporally encoded single-shot MRI.

    PubMed

    Chen, Lin; Bao, Lijun; Li, Jing; Cai, Shuhui; Cai, Congbo; Chen, Zhong

    2013-12-01

    Compared to the echo planar imaging (EPI), spatiotemporally encoded (SPEN) single-shot MRI holds better immunity to the field inhomogeneity, while retaining comparable spatial and temporal resolutions after the super-resolved reconstruction. Though various reconstruction methods have been proposed, the reconstructed SPEN images usually contain aliasing artifacts because of vast undersampling. A hybrid scheme based on random sampling, singular value decomposition (SVD) and compressed sensing (CS) was introduced to reduce these aliasing artifacts and improve the image quality. The efficiency of this hybrid scheme was demonstrated by numerical simulations and experiments on water phantom and in vivo rat brain. The hybrid scheme provided herein would benefit the SPEN approach in vast undersampling situation.

  18. Theory of single-shot phase contrast imaging in spinor Bose-Einstein condensates.

    PubMed

    Ilo-Okeke, Ebubechukwu O; Byrnes, Tim

    2014-06-13

    We introduce a theoretical framework for single-shot phase contrast imaging (PCI) measurements of spinor Bose-Einstein condensates (BECs). Our model allows for the simple calculation of the quantum backaction resulting from the measurement, and the amount of information that is read out. We find that there is an optimum time Gτ ∼ 1/N for the light-matter interaction (G is the ac Stark shift frequency, N is the number of particles in the BEC), where the maximum amount of information can be read out from the BEC. A universal information-disturbance tradeoff law ε(F)ε(G) ∝ 1/N(2) is found where ε(F) is the amount of backaction and ε(G) is the estimation error. The PCI measurement can also be found to be a direct probe of the quantum fluctuations of the BEC, via the noise of the PCI signal.

  19. A versatile diffractive maskless lithography for single-shot and serial microfabrication

    PubMed Central

    Jenness, Nathan J.; Hill, Ryan T.; Hucknall, Angus; Chilkoti, Ashutosh; Clark, Robert L.

    2010-01-01

    We demonstrate a diffractive maskless lithographic system that is capable of rapidly performing both serial and single-shot micropatterning. Utilizing the diffractive properties of phase holograms displayed on a spatial light modulator, arbitrary intensity distributions were produced to form two and three dimensional micropatterns/structures in a variety of substrates. A straightforward graphical user interface was implemented to allow users to load templates and change patterning modes within the span of a few minutes. A minimum resolution of ~700 nm is demonstrated for both patterning modes, which compares favorably to the 232 nm resolution limit predicted by the Rayleigh criterion. The presented method is rapid and adaptable, allowing for the parallel fabrication of microstructures in photoresist as well as the fabrication of protein microstructures that retain functional activity. PMID:20589036

  20. Single shot near edge x-ray absorption fine structure spectroscopy in the laboratory

    NASA Astrophysics Data System (ADS)

    Mantouvalou, I.; Witte, K.; Martyanov, W.; Jonas, A.; Grötzsch, D.; Streeck, C.; Löchel, H.; Rudolph, I.; Erko, A.; Stiel, H.; Kanngießer, B.

    2016-05-01

    With the help of adapted off-axis reflection zone plates, near edge X-ray absorption fine structure spectra at the C and N K-absorption edge have been recorded using a single 1.2 ns long soft X-ray pulse. The transmission experiments were performed with a laser-produced plasma source in the laboratory rendering time resolved measurements feasible independent on large scale facilities. A resolving power of E/ΔE ˜ 950 at the respective edges could be demonstrated. A comparison of single shot spectra with those collected with longer measuring time proves that all features of the used reference samples (silicon nitrate and polyimide) can be resolved in 1.2 ns. Hence, investigations of radiation sensitive biological specimen become possible due to the high efficiency of the optical elements enabling low dose experiments.

  1. Single-shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator

    NASA Astrophysics Data System (ADS)

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michael; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    We propose and demonstrate a new read-out technique for a superconducting qubit by dispersively coupling it to a Josephson parametric oscillator. We employ a tunable quarter-wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185 +/- ∑ 15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot readout performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing. Support came from the Wallenberg foundation, the European Research Council (ERC), the Royal Swedish Academy of Science (KVA), the European project ScaleQIT, STINT, and Marie Curie CIG.

  2. Design and operation of a hard x-ray transmissive single-shot spectrometer at LCLS

    NASA Astrophysics Data System (ADS)

    Zhu, D.; Cammarata, M.; Feldkamp, J.; Fritz, D. M.; Hastings, J.; Lee, S.; Lemke, H. T.; Robert, A.; Turner, J.; Feng, Y.

    2013-03-01

    We describe the design and operation of a transmissive single-shot spectrometer for the measurement of hard x-ray free electron laser (FEL) source spectrum at the Linac Coherent Light Source (LCLS). The spectrometer was built around a 10 μm thick near-perfect silicon single crystal that was cylindrically bent. Its energy range covered the full FEL bandwidth while its resolution was sufficient for resolving single spectral spikes characteristics of the FELs. Its application will not only greatly facilitate the understanding and optimization of the x-ray FEL sources, but can also serve as an invaluable inline diagnostic tool for experiments where the spectral content of the source plays an important role in data interpretation.

  3. Miniaturized Single-Shot Valve and its Application to the ExoMars Pasteur Payload

    NASA Technical Reports Server (NTRS)

    Muller, Pierre; Henkel, Hartmut; Klinkner, Sabine

    2010-01-01

    Hermetically sealing a gas tank and opening it into tubing under telecommand control is a function required in various space instruments. There are a number of space valves that are power saving, withstand vibration, and do not contaminate the gas. But none of them combines these features with low mass and the ability to withstand temperatures of 130 C during the sterilization process mandatory for planetary missions. In this paper, a novel miniature valve is presented, which is particularly adapted to space applications. It is electrically actuated, utilizing a bimetallic snap-disc that pierces a metallic membrane by a needle pin, thereby opening the valve. The design of this single-shot valve is such that it allows it to withstand a temperature of 130 C and a pressure of 50 bars. The valve is also lightweight (6.62 g) and it requires only 9 W to operate.

  4. Trust Region Methods for the Estimation of a Complex Exponential Decay Model in MRI With a Single-Shot or Multi-Shot Trajectory.

    PubMed

    Hu, Chenxi; Reeves, Stanley J

    2015-11-01

    Joint estimation of spin density R2* decay and OFF-resonance frequency maps is very useful in many magnetic resonance imaging applications. The standard multi-echo approach can achieve high accuracy but requires a long acquisition time for sampling multiple k-space frames. There are many approaches to accelerate the acquisition. Among them, single-shot or multi-shot trajectory-based sampling has recently drawn attention due to its fast data acquisition. However, this sampling strategy destroys the Fourier relationship between k-space and images, leading to a great challenge for the reconstruction. In this paper, we present two trust region methods based on two different linearization strategies for the nonlinear signal model. A trust region is defined as a local area in the variable space where a local linear approximation is trustable. In each iteration, the method minimizes a local approximation within a trust region so that the step size can be kept in a suitable scale. A continuation scheme is applied to reduce the regularization gradually over the parameter maps and facilitates convergence from poor initializations. The two trust region methods are compared with the two other previously proposed methods--the nonlinear conjugate gradients and the gradual refinement algorithm. Experiments based on various synthetic data and real phantom data show that the two trust region methods have a clear advantage in both speed and stability. PMID:26068316

  5. Ultrafast measurements of optical spectral coherence by single-shot time-stretch interferometry.

    PubMed

    Xu, Yiqing; Wei, Xiaoming; Ren, Zhibo; Wong, Kenneth K Y; Tsia, Kevin K

    2016-01-01

    The palette of laser technology has significantly been enriched by the innovations in ultrafast optical pulse generation. Our knowledge of the complex pulse dynamics, which is often highly nonlinear and stochastic in nature, is however limited by the scarcity of technologies that can measure fast variation/fluctuation of the spectral phase (or coherence) and amplitude in real-time, continuously. To achieve this goal, we demonstrate ultrafast interferometry enabled by optical time-stretch for real- time spectral coherence characterization with microsecond-resolution. Accessing the single-shot interferograms continuously, it further reveals the degree of second-order coherence, defined by the cross-spectral density function, at high speed-a capability absent in any existing spectroscopic measurement tools. As the technique can simultaneously measure both the high-speed variations of spectrally resolved coherence and intensity, time-stretch interferometry could create a new arena for ultrafast pulse characterization, especially favorable for probing and understanding the non-repetitive or stochastic dynamics in real-time. PMID:27295560

  6. Correcting surface coil excitation inhomogeneities in single-shot SPatiotemporal ENcoding (SPEN) MRI

    PubMed Central

    Hyacinthe, Jean-Noel; Kunz, Nicolas; Gruetter, Rolf; Comment, Arnaud; Frydman, Lucio

    2016-01-01

    Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences –including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to reduce RF transmit inhomogeneities and thus improve sensitivity and image fidelity. PMID:26363583

  7. Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI.

    PubMed

    Schmidt, Rita; Mishkovsky, Mor; Hyacinthe, Jean-Noel; Kunz, Nicolas; Gruetter, Rolf; Comment, Arnaud; Frydman, Lucio

    2015-10-01

    Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences - including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to compensate for the RF transmit inhomogeneities and thus improve sensitivity and image fidelity.

  8. Improved crystal orientation and physical properties from single-shot XFEL stills.

    PubMed

    Sauter, Nicholas K; Hattne, Johan; Brewster, Aaron S; Echols, Nathaniel; Zwart, Petrus H; Adams, Paul D

    2014-12-01

    X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg's law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.

  9. Improved crystal orientation and physical properties from single-shot XFEL stills

    SciTech Connect

    Sauter, Nicholas K.; Hattne, Johan; Brewster, Aaron S.; Echols, Nathaniel; Zwart, Petrus H.; Adams, Paul D.

    2014-11-28

    X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg's law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.

  10. Single-shot gas-phase thermometry by time-to-frequency mapping of coherence dephasing.

    PubMed

    Yue, Orin; Bremer, Marshall T; Pestov, Dmitry; Gord, James R; Roy, Sukesh; Dantus, Marcos

    2012-08-01

    We demonstrate a single-beam coherent anti-Stokes Raman scattering (CARS) technique for gas-phase thermometry that assesses the species-specific local gas temperature by single-shot time-to-frequency mapping of Raman-coherence dephasing. The proof-of-principle experiments are performed with air in a temperature-controlled gas cell. Impulsive excitation of molecular vibrations by an ultrashort pump/Stokes pulse is followed by multipulse probing of the 2330 cm(-1) Raman transition of N(2). This sequence of colored probe pulses, delayed in time with respect to each other and corresponding to three isolated spectral bands, imprints the coherence dephasing onto the measured CARS spectrum. For calibration purposes, the dephasing rates are recorded at various gas temperatures, and the relationship is fitted to a linear regression. The calibration data are then used to determine the gas temperature and are shown to provide better than 15 K accuracy. The described approach is insensitive to pulse energy fluctuations and can, in principle, gauge the temperature of multiple chemical species in a single laser shot, which is deemed particularly valuable for temperature profiling of reacting flows in gas-turbine combustors.

  11. Single-shot x-ray phase contrast imaging with an algorithmic approach using spectral detection

    NASA Astrophysics Data System (ADS)

    Das, Mini; Park, Chan-Soo; Fredette, Nathaniel R.

    2016-04-01

    X-ray phase contrast imaging has been investigated during the last two decades for potential benefits in soft tissue imaging. Long imaging time, high radiation dose and general measurement complexity involving motion of x-ray optical components have prevented the clinical translation of these methods. In all existing popular phase contrast imaging methods, multiple measurements per projection angle involving motion of optical components are required to achieve quantitatively accurate estimation of absorption, phase and differential phase. Recently we proposed an algorithmic approach to use spectral detection data in a phase contrast imaging setup to obtain absorption, phase and differential phase in a single-step. Our generic approach has been shown via simulations in all three types of phase contrast imaging: propagation, coded aperture and grating interferometry. While other groups have used spectral detector in phase contrast imaging setups, our proposed method is unique in outlining an approach to use this spectral data to simplify phase contrast imaging. In this abstract we show the first experimental proof of our single-shot phase retrieval using a Medipix3 photon counting detector in an edge illumination aperture (also referred to as coded aperture) phase contrast set up as well as for a free space propagation setup. Our preliminary results validate our new transport equation for edge illumination PCI and our spectral phase retrieval algorithm for both PCI methods being investigated. Comparison with simulations also point to excellent performance of Medipix3 built-in charge sharing correction mechanism.

  12. Single-shot gas-phase thermometry by time-to-frequency mapping of coherence dephasing.

    PubMed

    Yue, Orin; Bremer, Marshall T; Pestov, Dmitry; Gord, James R; Roy, Sukesh; Dantus, Marcos

    2012-08-01

    We demonstrate a single-beam coherent anti-Stokes Raman scattering (CARS) technique for gas-phase thermometry that assesses the species-specific local gas temperature by single-shot time-to-frequency mapping of Raman-coherence dephasing. The proof-of-principle experiments are performed with air in a temperature-controlled gas cell. Impulsive excitation of molecular vibrations by an ultrashort pump/Stokes pulse is followed by multipulse probing of the 2330 cm(-1) Raman transition of N(2). This sequence of colored probe pulses, delayed in time with respect to each other and corresponding to three isolated spectral bands, imprints the coherence dephasing onto the measured CARS spectrum. For calibration purposes, the dephasing rates are recorded at various gas temperatures, and the relationship is fitted to a linear regression. The calibration data are then used to determine the gas temperature and are shown to provide better than 15 K accuracy. The described approach is insensitive to pulse energy fluctuations and can, in principle, gauge the temperature of multiple chemical species in a single laser shot, which is deemed particularly valuable for temperature profiling of reacting flows in gas-turbine combustors. PMID:22747235

  13. Single-shot, planar infrared imaging in flames using polarization spectroscopy.

    PubMed

    Sun, Zhiwei; Zetterberg, Johan; Alwahabi, Zeyad; Aldén, Marcus; Li, Zhongshan

    2015-11-16

    Planar infrared visualization of species in flames is challenging due to the severe thermal radiation background and relatively weak fluorescence quantum yields from ro-vibration transitions. In this express, we report imaging of molecular species in a flame via an absorption-based coherent optical method, namely infrared polarization spectroscopy (IRPS). Single-shot, planar imaging of hydrogen fluoride (HF) has been achieved in a premixed CH(4)/O(2) Bunsen flame, being seeded with a small amount of SF(6). The HF molecule was excited through a rovibrational transition at around 2.5 µm, which belongs to the fundamental vibration band. High spatial resolution was guaranteed using an orthorgonal pump-probe geometry, and an effective suppression of thermal background emission was achieved owing to the coherent nature of the demonstrated two-dimensional IRPS. Other advantages, e.g. high temporal resolution and species-specificity, are also features of this laser-based technique, which make it suitable for imaging of non-fluorescent but infrared active gaseous molecules in harsh environments. PMID:26698520

  14. Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI

    NASA Astrophysics Data System (ADS)

    Schmidt, Rita; Mishkovsky, Mor; Hyacinthe, Jean-Noel; Kunz, Nicolas; Gruetter, Rolf; Comment, Arnaud; Frydman, Lucio

    2015-10-01

    Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences - including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to compensate for the RF transmit inhomogeneities and thus improve sensitivity and image fidelity.

  15. Direct single-shot phase retrieval for separated objects (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Leshem, Ben; Xu, Rui; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-03-01

    The phase retrieval problem arises in various fields ranging from physics and astronomy to biology and microscopy. Computational reconstruction of the Fourier phase from a single diffraction pattern is typically achieved using iterative alternating projections algorithms imposing a non-convex computational challenge. A different approach is holography, relying on a known reference field. Here we present a conceptually new approach for the reconstruction of two (or more) sufficiently separated objects. In our approach we combine the constraint the objects are finite as well as the information in the interference between them to construct an overdetermined set of linear equations. We show that this set of equations is guaranteed to yield the correct solution almost always and that it can be solved efficiently by standard numerical algebra tools. Essentially, our method combine commonly used constraint (that the object is finite) with a holographic approach (interference information). It differs from holographic methods in the fact that a known reference field is not required, instead the unknown objects serve as reference to one another (hence blind holography). Our method can be applied in a single-shot for two (or more) separated objects or with several measurements with a single object. It can benefit phase imaging techniques such as Fourier phytography microscopy, as well as coherent diffractive X-ray imaging in which the generation of a well-characterized, high resolution reference beam imposes a major challenge. We demonstrate our method experimentally both in the optical domain and in the X-ray domain using XFEL pulses.

  16. Correcting surface coil excitation inhomogeneities in single-shot SPEN MRI.

    PubMed

    Schmidt, Rita; Mishkovsky, Mor; Hyacinthe, Jean-Noel; Kunz, Nicolas; Gruetter, Rolf; Comment, Arnaud; Frydman, Lucio

    2015-10-01

    Given their high sensitivity and ability to limit the field of view (FOV), surface coils are often used in magnetic resonance spectroscopy (MRS) and imaging (MRI). A major downside of surface coils is their inherent radiofrequency (RF) B1 heterogeneity across the FOV, decreasing with increasing distance from the coil and giving rise to image distortions due to non-uniform spatial responses. A robust way to compensate for B1 inhomogeneities is to employ adiabatic inversion pulses, yet these are not well adapted to all imaging sequences - including to single-shot approaches like echo planar imaging (EPI). Hybrid spatiotemporal encoding (SPEN) sequences relying on frequency-swept pulses provide another ultrafast MRI alternative, that could help solve this problem thanks to their built-in heterogeneous spatial manipulations. This study explores how this intrinsic SPEN-based spatial discrimination, could be used to compensate for the B1 inhomogeneities inherent to surface coils. Experiments carried out in both phantoms and in vivo rat brains demonstrate that, by suitably modulating the amplitude of a SPEN chirp pulse that progressively excites the spins in a direction normal to the coil, it is possible to compensate for the RF transmit inhomogeneities and thus improve sensitivity and image fidelity. PMID:26363583

  17. Improved crystal orientation and physical properties from single-shot XFEL stills

    DOE PAGES

    Sauter, Nicholas K.; Hattne, Johan; Brewster, Aaron S.; Echols, Nathaniel; Zwart, Petrus H.; Adams, Paul D.

    2014-11-28

    X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model themore » diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg's law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.« less

  18. Frequency-Domain Tomography for Single-shot, Ultrafast Imaging of Evolving Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Downer, Michael

    2011-10-01

    Intense laser pulses propagating through plasma create plasma wakefields that often evolve significantly, e.g. by expanding and contracting. However, such dynamics are known in detail only through intensive simulations. Laboratory visualization of evolving plasma wakes in the ``bubble'' regime is important for optimizing and scaling laser-plasma accelerators. Recently snap-shots of quasi-static wakes were recorded using frequency-domain holography (FDH). To visualize the wake's evolution, we have generalized FDH to frequency-domain tomography (FDT), which uses multiple probes propagating at different angles with respect to the pump pulse. Each probe records a phase streak, imprinting a partial record of the evolution of pump-created structures. We then topographically reconstruct the full evolution from all phase streaks. To prove the concept, a prototype experiment visualizing nonlinear index evolution in glass is demonstrated. Four probes propagating at 0, 0.6, 2, 14 degrees to the index ``bubble'' are angularly and temporally multiplexed to a single spectrometer to achieve cost-effective FDT. From these four phase streaks, an FDT algorithm analogous to conventional CT yields a single-shot movie of the pump's self-focusing dynamics.

  19. Ultrafast measurements of optical spectral coherence by single-shot time-stretch interferometry

    PubMed Central

    Xu, Yiqing; Wei, Xiaoming; Ren, Zhibo; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2016-01-01

    The palette of laser technology has significantly been enriched by the innovations in ultrafast optical pulse generation. Our knowledge of the complex pulse dynamics, which is often highly nonlinear and stochastic in nature, is however limited by the scarcity of technologies that can measure fast variation/fluctuation of the spectral phase (or coherence) and amplitude in real-time, continuously. To achieve this goal, we demonstrate ultrafast interferometry enabled by optical time-stretch for real- time spectral coherence characterization with microsecond-resolution. Accessing the single-shot interferograms continuously, it further reveals the degree of second-order coherence, defined by the cross-spectral density function, at high speed-a capability absent in any existing spectroscopic measurement tools. As the technique can simultaneously measure both the high-speed variations of spectrally resolved coherence and intensity, time-stretch interferometry could create a new arena for ultrafast pulse characterization, especially favorable for probing and understanding the non-repetitive or stochastic dynamics in real-time. PMID:27295560

  20. Ultrafast measurements of optical spectral coherence by single-shot time-stretch interferometry

    NASA Astrophysics Data System (ADS)

    Xu, Yiqing; Wei, Xiaoming; Ren, Zhibo; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2016-06-01

    The palette of laser technology has significantly been enriched by the innovations in ultrafast optical pulse generation. Our knowledge of the complex pulse dynamics, which is often highly nonlinear and stochastic in nature, is however limited by the scarcity of technologies that can measure fast variation/fluctuation of the spectral phase (or coherence) and amplitude in real-time, continuously. To achieve this goal, we demonstrate ultrafast interferometry enabled by optical time-stretch for real- time spectral coherence characterization with microsecond-resolution. Accessing the single-shot interferograms continuously, it further reveals the degree of second-order coherence, defined by the cross-spectral density function, at high speed-a capability absent in any existing spectroscopic measurement tools. As the technique can simultaneously measure both the high-speed variations of spectrally resolved coherence and intensity, time-stretch interferometry could create a new arena for ultrafast pulse characterization, especially favorable for probing and understanding the non-repetitive or stochastic dynamics in real-time.

  1. Single shot whole brain imaging using spherical stack of spirals trajectories.

    PubMed

    Assländer, Jakob; Zahneisen, Benjamin; Hugger, Thimo; Reisert, Marco; Lee, Hsu-Lei; LeVan, Pierre; Hennig, Jürgen

    2013-06-01

    MR-encephalography allows the observation of functional signal in the brain at a frequency of 10 Hz, permitting filtering of physiological "noise" and the detection of single event activations. High temporal resolution is achieved by the use of undersampled non-Cartesian trajectories, parallel imaging and regularized image reconstruction. MR-encephalography is based on 3D-encoding, allowing undersampling in two dimensions and providing advantages in terms of signal to noise ratio. Long readout times, which are necessary for single shot whole brain imaging (up to 75 ms), cause off-resonance artifacts. To meet this issue, a spherical stack of spirals trajectory is proposed in this work. By examining the trajectories in local k-space, it is shown that in areas of strong susceptibility gradients spatial information is fundamentally lost, making a meaningful image reconstruction impossible in the affected areas. It is shown that the loss of spatial information is reduced when using a stack of spirals trajectory compared to concentric shells. PMID:23384526

  2. Simultaneous measurement of two ultrashort laser pulses from a single spectrogram in a single shot

    SciTech Connect

    Kane, D.J.; Rodriguez, G.; Taylor, A.J.; Clement, T.S. ||

    1997-04-01

    Frequency-resolved optical gating (FROG) is a technique that produces a spectrogram of an ultrashort laser pulse. The intensity and phase of the ultrashort laser pulse can be determined through solving for the phase of the spectrogram with an iterative, phase-retrieval algorithm. This work presents a new phase-retrieval algorithm that retrieves both the probe and the gate pulses independently by converting the FROG phase-retrieval problem to an eigenvector problem. The new algorithm is robust and general. It is tested theoretically by use of synthetic data sets and experimentally by use of single-shot, polarization-gate FROG. We independently and simultaneously characterize the electric field amplitude and phase of a pulse (probe) that was passed though 200 mm of BK7 glass and the amplitude of an unchanged pulse (gate) from an amplified Ti:sapphire laser. When the effect of the 200 mm of BK7 glass was removed mathematically from the probe, there was good agreement between the measured gate and the calculated, prechirped probe. {copyright} 1997 Optical Society of America

  3. Flexible reduced field of view magnetic resonance imaging based on single-shot spatiotemporally encoded technique

    NASA Astrophysics Data System (ADS)

    Li, Jing; Cai, Cong-Bo; Chen, Lin; Chen, Ying; Qu, Xiao-Bo; Cai, Shu-Hui

    2015-10-01

    In many ultrafast imaging applications, the reduced field-of-view (rFOV) technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporally-encoded (SPEN) method offers an inherent applicability to rFOV imaging. In this study, a flexible rFOV imaging method is presented and the superiority of the SPEN approach in rFOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging (EPI) experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the rFOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest (ROIs) with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474236, 81171331, and U1232212).

  4. Improved crystal orientation and physical properties from single-shot XFEL stills

    PubMed Central

    Sauter, Nicholas K.; Hattne, Johan; Brewster, Aaron S.; Echols, Nathaniel; Zwart, Petrus H.; Adams, Paul D.

    2014-01-01

    X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg’s law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise. PMID:25478847

  5. Improved crystal orientation and physical properties from single-shot XFEL stills

    SciTech Connect

    Sauter, Nicholas K. Hattne, Johan; Brewster, Aaron S.; Echols, Nathaniel; Zwart, Petrus H.; Adams, Paul D.

    2014-12-01

    X-ray free-electron laser crystallography relies on the collection of still-shot diffraction patterns. New methods are developed for optimal modeling of the crystals’ orientations and mosaic block properties. X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg’s law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.

  6. One-dimensional single-shot thermometry in flames using femtosecond-CARS line imaging.

    PubMed

    Kulatilaka, W D; Stauffer, H U; Gord, J R; Roy, S

    2011-11-01

    We report single-laser-shot one-dimensional thermometry in flames using femtosecond coherent anti-Stokes Raman scattering (fs-CARS) line imaging. Fs-CARS enables high-repetition-rate (1-10 kHz), nearly collision-free measurement of temperature and species concentration in reacting flows. Two high-power 800 nm beams are used as the pump and probe beams and a 983 nm beam is used as the Stokes beam for CARS signal generation from the N2Q-branch transitions at ∼2330 cm(-1). The probe beam is frequency-chirped for single-laser-shot imaging. All three laser beams are formed into sheets and crossed in a line which forms the probe region. The resulting 1D line-CARS signal at ∼675 nm is spatially and spectrally resolved and recorded as a two-dimensional (2D) image. Single-shot temperature measurements are demonstrated in flat-field flames up to temperatures exceeding 2000 K, demonstrating the potential of fs-CARS line imaging for high-repetition-rate thermometry in turbulent flames. Such measurements can provide valuable data to validate complex turbulent-combustion models as well as increase the understanding of the spatio-temporal instabilities in practical combustion devices such as modern gas-turbine combustors and augmentors.

  7. Single-shot temporal envelope measurement of ultrashort extreme-UV pulses by spatially encoded transmission gating.

    PubMed

    Chu, Hsu-hsin; Yang, Chi-Hsiang; Liu, Shih-Cheng; Wang, Jyhpyng

    2015-12-28

    Single-shot ultrashort extreme-UV(EUV) pulse waveform measurement is demonstrated by utilizing strong field ionization of H2 gas for transmission gating. A cross-propagating intense near-IR gate pulse ionizes the EUV absorbing H2 molecules into EUV-non-absorbing H2++ (two protons) and creates a time sweep of transmission encoded spatially across the EUV pulse. The temporal envelope is then retrieved from the lopsided spatial profile of the transmitted pulse. This method not only measures EUV temporal envelope for each single shot, but also determines timing jitter and envelope fluctuation statistically, thus is particularly useful for characterizing low-repetition-rate fluctuating EUV/soft x-ray sources. PMID:26832064

  8. Note: Single-shot time-domain spectroscopy and spatial profiling of terahertz pulses from intense laser systems.

    PubMed

    Zhang, T J; Jin, Z; Wakamatsu, S; Hosokai, T; Yugami, N; Kodama, R

    2016-06-01

    Single-shot terahertz time-domain spectroscopy is presented with directly encoded spatial resolution. A single reflective echelon and multiple semi-cylindrical lenses are used to obtain both the temporal waveform and the spatial distribution of the terahertz field. This system can be used to rapidly characterize terahertz pulses generated by high power pulsed laser systems, which themselves suffer from large pulse energy and spectrum fluctuations. PMID:27370502

  9. Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns (CXIDB ID 9)

    DOE Data Explorer

    Loh, Ne-Te Duane

    2011-08-01

    These 2000 single-shot diffraction patterns include were either background-scattering only or hits (background-scattering plus diffraction signal from sub-micron ellipsoidal particles at random, undetermined orientations). Candidate hits were identified by eye, and the remainder were presumed as background. 54 usable, background-subtracted hits in this set (procedure in referenced article) were used to reconstruct the 3D diffraction intensities of the average ellipsoidal particle.

  10. Real-time single-shot measurement and correction of pulse phase and amplitude for ultrafast lasers

    NASA Astrophysics Data System (ADS)

    Pestov, Dmitry; Ryabtsev, Anton; Rasskazov, Gennady; Lozovoy, Vadim V.; Dantus, Marcos

    2014-05-01

    The transition of femtosecond lasers from the laboratory to commercial applications requires real-time automated pulse compression, ensuring optimum performance without assistance. Single-shot phase measurements together with closed-loop optimization based on real-time multiphoton intrapulse interference phase scan are demonstrated. On-the-fly correction of amplitude, as well as second- and third-order phase distortions based on the real-time measurements, is accomplished by a pulse shaper.

  11. Single-shot Zeff dense plasma diagnostic through simultaneous refraction and attenuation measurements with a Talbot–Lau x-ray moiré deflectometer

    DOE PAGES

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2015-03-23

    The Talbot–Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n = 1 - δ + iβ of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both δ and β, which are directly related to the electron density ne and the attenuation coefficient μ, respectively. Since δ and β depend on the effective atomic number Zeff, a map can be obtained from the ratio between phase and absorptionmore » images acquired in a single shot. The Talbot–Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Zeff values of test objects within the 4–12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Zeff mapping of objects does not require previous knowledge of sample length or shape. The determination of Zeff from refraction and attenuation measurements with Moiré deflectometry could be of high interest to various domains of HED research, such as shocked materials and ICF experiments, as well as material science and NDT.« less

  12. Single-shot Z(eff) dense plasma diagnostic through simultaneous refraction and attenuation measurements with a Talbot-Lau x-ray moiré deflectometer.

    PubMed

    Valdivia, M P; Stutman, D; Finkenthal, M

    2015-04-01

    The Talbot-Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n=1-δ+iβ of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both δ and β, which are directly related to the electron density n(e) and the attenuation coefficient μ, respectively. Since δ and β depend on the effective atomic number Z(eff), a map can be obtained from the ratio between phase and absorption images acquired in a single shot. The Talbot-Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Z(eff) values of test objects within the 4-12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Z(eff) mapping of objects does not require previous knowledge of sample length or shape. The determination of Z(eff) from refraction and attenuation measurements with moiré deflectometry could be of high interest to various domains of high energy density research, such as shocked materials and inertial confinement fusion experiments, as well as material science and nondestructive testing.

  13. X-Ray Emission Spectrometer Design with Single-Shot Pump-Probe and Resonant Excitation Capabilities

    SciTech Connect

    Spoth, Katherine; /SUNY, Buffalo /SLAC

    2012-08-28

    Core-level spectroscopy in the soft X-ray regime is a powerful tool for the study of chemical bonding processes. The ultrafast, ultrabright X-ray pulses generated by the Linac Coherent Light Source (LCLS) allow these reactions to be studied in greater detail than ever before. In this study, we investigated a conceptual design of a spectrometer for the LCLS with imaging in the non-dispersive direction. This would allow single-shot collection of X-ray emission spectroscopy (XES) measurements with varying laser pump X-ray probe delay or a variation of incoming X-ray energy over the illuminated area of the sample. Ray-tracing simulations were used to demonstrate how the components of the spectrometer affect its performance, allowing a determination of the optimal final design. These simulations showed that the spectrometer's non-dispersive focusing is extremely sensitive to the size of the sample footprint; the spectrometer is not able to image a footprint width larger than one millimeter with the required resolution. This is compatible with a single shot scheme that maps out the laser pump X-ray probe delay in the non-dispersive direction as well as resonant XES applications at normal incidence. However, the current capabilities of the Soft X-Ray (SXR) beamline at the LCLS do not produce the required energy range in a small enough sample footprint, hindering the single shot resonant XES application at SXR for chemical dynamics studies at surfaces. If an upgraded or future beamline at LCLS is developed with lower monochromator energy dispersion the width can be made small enough at the required energy range to be imaged by this spectrometer design.

  14. Single-shot measurement of the spectral envelope of broad-bandwidth terahertz pulses from femtosecond electron bunches

    SciTech Connect

    van Tilborg, Jeroen; Toth, Csaba; Matlis, Nicholas; Plateau, Guillaume; Leemans, Wim

    2011-06-17

    We present a new approach (demonstrated experimentally and through modeling) to characterize the spectral envelope of a terahertz (THz) pulse in a single shot. The coherent THz pulse is produced by a femtosecond electron bunch and contains information on the bunch duration. The technique, involving a single low-power laser probe pulse, is an extension of the conventional spectral encoding method (limited in time resolution to hundreds of femtoseconds) into a regime only limited in resolution by the laser pulse length (tens of femtoseconds). While only the bunch duration is retrieved (and not the exact charge profile), such a measurement provides a useful and critical parameter for optimization of the electron accelerator.

  15. Real time quantitative phase microscopy based on single-shot transport of intensity equation (ssTIE) method

    NASA Astrophysics Data System (ADS)

    Yu, Wei; Tian, Xiaolin; He, Xiaoliang; Song, Xiaojun; Xue, Liang; Liu, Cheng; Wang, Shouyu

    2016-08-01

    Microscopy based on transport of intensity equation provides quantitative phase distributions which opens another perspective for cellular observations. However, it requires multi-focal image capturing while mechanical and electrical scanning limits its real time capacity in sample detections. Here, in order to break through this restriction, real time quantitative phase microscopy based on single-shot transport of the intensity equation method is proposed. A programmed phase mask is designed to realize simultaneous multi-focal image recording without any scanning; thus, phase distributions can be quantitatively retrieved in real time. It is believed the proposed method can be potentially applied in various biological and medical applications, especially for live cell imaging.

  16. Averaging of Replicated Pulses for Enhanced-Dynamic-Range Single-Shot Measurement of Nanosecond Optical Pulses

    SciTech Connect

    Marciante, J.R.; Donaldson, W.R.; Roides, R.G.

    2007-10-04

    Measuring optical pulse shapes beyond the dynamic range of oscilloscopes is achieved by temporal pulse stacking in a low-loss, passive, fiber-optic network. Optical pulses are averaged with their time-delayed replicas without introducing additional noise or jitter, allowing for high-contrast pulse-shape measurements of single-shot events. A dynamic-range enhancement of three bits is experimentally demonstrated and compared with conventional multi-shot averaging. This technique can be extended to yield an increase of up to seven bits of additional dynamic range over nominal oscilloscope performance.

  17. Toward unsupervised single-shot diffractive imaging of heterogeneous particles using X-ray free-electron lasers.

    PubMed

    Park, Hyung Joo; Loh, N Duane; Sierra, Raymond G; Hampton, Christina Y; Starodub, Dmitri; Martin, Andrew V; Barty, Anton; Aquila, Andrew; Schulz, Joachim; Steinbrener, Jan; Shoeman, Robert L; Lomb, Lukas; Kassemeyer, Stephan; Bostedt, Christoph; Bozek, John; Epp, Sascha W; Erk, Benjamin; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Rudek, Benedikt; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Hauser, Guenter; Holl, Peter; Pedersoli, Emanuele; Liang, Mengning; Hunter, Mark S; Gumprecht, Lars; Coppola, Nicola; Wunderer, Cornelia; Graafsma, Heinz; Maia, Filipe R N C; Ekeberg, Tomas; Hantke, Max; Fleckenstein, Holger; Hirsemann, Helmut; Nass, Karol; Tobias, Herbert J; Farquar, George R; Benner, W Henry; Hau-Riege, Stefan; Reich, Christian; Hartmann, Andreas; Soltau, Heike; Marchesini, Stefano; Bajt, Sasa; Barthelmess, Miriam; Strueder, Lothar; Ullrich, Joachim; Bucksbaum, Philip; Frank, Matthias; Schlichting, Ilme; Chapman, Henry N; Bogan, Michael J; Elser, Veit

    2013-11-18

    Single shot diffraction imaging experiments via X-ray free-electron lasers can generate as many as hundreds of thousands of diffraction patterns of scattering objects. Recovering the real space contrast of a scattering object from these patterns currently requires a reconstruction process with user guidance in a number of steps, introducing severe bottlenecks in data processing. We present a series of measures that replace user guidance with algorithms that reconstruct contrasts in an unsupervised fashion. We demonstrate the feasibility of automating the reconstruction process by generating hundreds of contrasts obtained from soot particle diffraction experiments.

  18. Femtosecond Single-Shot Imaging of Nanoscale Ferromagnetic Order in Co/Pd Multilayers using Resonant X-ray Holography

    SciTech Connect

    Wang, Tianhan; Zhu, Diling; Benny Wu,; Graves, Catherine; Schaffert, Stefan; Rander, Torbjorn; Muller, leonard; Vodungbo, Boris; Baumier, Cedric; Bernstein, David P.; Brauer, Bjorn; Cros, Vincent; Jong, Sanne de; Delaunay, Renaud; Fognini, Andreas; Kukreja, Roopali; Lee, Sooheyong; Lopez-Flores, Victor; Mohanty, Jyoti; Pfau, Bastian; Popescu, 5 Horia

    2012-05-15

    We present the first single-shot images of ferromagnetic, nanoscale spin order taken with femtosecond x-ray pulses. X-ray-induced electron and spin dynamics can be outrun with pulses shorter than 80 fs in the investigated fluence regime, and no permanent aftereffects in the samples are observed below a fluence of 25 mJ/cm{sup 2}. Employing resonant spatially-muliplexed x-ray holography results in a low imaging threshold of 5 mJ/cm{sup 2}. Our results open new ways to combine ultrafast laser spectroscopy with sequential snapshot imaging on a single sample, generating a movie of excited state dynamics.

  19. Toward unsupervised single-shot diffractive imaging of heterogeneous particles using X-ray free-electron lasers.

    PubMed

    Park, Hyung Joo; Loh, N Duane; Sierra, Raymond G; Hampton, Christina Y; Starodub, Dmitri; Martin, Andrew V; Barty, Anton; Aquila, Andrew; Schulz, Joachim; Steinbrener, Jan; Shoeman, Robert L; Lomb, Lukas; Kassemeyer, Stephan; Bostedt, Christoph; Bozek, John; Epp, Sascha W; Erk, Benjamin; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Rudek, Benedikt; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Hauser, Guenter; Holl, Peter; Pedersoli, Emanuele; Liang, Mengning; Hunter, Mark S; Gumprecht, Lars; Coppola, Nicola; Wunderer, Cornelia; Graafsma, Heinz; Maia, Filipe R N C; Ekeberg, Tomas; Hantke, Max; Fleckenstein, Holger; Hirsemann, Helmut; Nass, Karol; Tobias, Herbert J; Farquar, George R; Benner, W Henry; Hau-Riege, Stefan; Reich, Christian; Hartmann, Andreas; Soltau, Heike; Marchesini, Stefano; Bajt, Sasa; Barthelmess, Miriam; Strueder, Lothar; Ullrich, Joachim; Bucksbaum, Philip; Frank, Matthias; Schlichting, Ilme; Chapman, Henry N; Bogan, Michael J; Elser, Veit

    2013-11-18

    Single shot diffraction imaging experiments via X-ray free-electron lasers can generate as many as hundreds of thousands of diffraction patterns of scattering objects. Recovering the real space contrast of a scattering object from these patterns currently requires a reconstruction process with user guidance in a number of steps, introducing severe bottlenecks in data processing. We present a series of measures that replace user guidance with algorithms that reconstruct contrasts in an unsupervised fashion. We demonstrate the feasibility of automating the reconstruction process by generating hundreds of contrasts obtained from soot particle diffraction experiments. PMID:24514385

  20. Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

    PubMed

    Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

    2014-01-01

    Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge.

  1. Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass

    NASA Astrophysics Data System (ADS)

    Garzillo, Valerio; Jukna, Vytautas; Couairon, Arnaud; Grigutis, Robertas; Di Trapani, Paolo; Jedrkiewicz, Ottavia

    2016-07-01

    We investigate the generation of high aspect ratio microstructures across 0.7 mm thick glass by means of single shot Bessel beam laser direct writing. We study the effect on the photoinscription of the cone angle, as well as of the energy and duration of the ultrashort laser pulse. The aim of the study is to optimize the parameters for the writing of a regular microstructure due to index modification along the whole sample thickness. By using a spectrally resolved single pulse transmission diagnostics at the output surface of the glass, we correlate the single shot material modification with observations of the absorption in different portions of the retrieved spectra, and with the absence or presence of spectral modulation. Numerical simulations of the evolution of the Bessel pulse intensity and of the energy deposition inside the sample help us interpret the experimental results that suggest to use picosecond pulses for an efficient and more regular energy deposition. Picosecond pulses take advantage of nonlinear plasma absorption and avoid temporal dynamics effects which can compromise the stationarity of the Bessel beam propagation.

  2. Single-shot dual-wavelength phase reconstruction in off-axis digital holography with polarization-multiplexing transmission.

    PubMed

    Wang, Zhe; Jiang, Zhuqing; Chen, Yifei

    2016-08-01

    A new system for single-shot dual-wavelength digital holographic microscopy with polarization-multiplexing path-shared transmission is presented. The key feature of the optical configuration is that the interference waves of two wavelengths having orthogonal polarization can transmit in the same interferometer paths at the same time, and two polarizers orthogonal to each other are placed in front of the CCD to realize single-shot recording of two holograms. The correlative filtering algorithm of the spatial-frequency spectrum for dual-wavelength digital holograms is reliable and efficient in the dual-wavelength path-shared configuration. The phase reconstruction in dual-wavelength digital holographic imaging is achieved by using this filtering algorithm. The experiment results of phase reconstruction of a groove grating demonstrate the reliability and validity of this optical configuration and the correlative filtering algorithm. This polarization-multiplexing configuration for dual-wavelength digital holography is compact and has more flexibility for the replacement of different-wavelength lasers. PMID:27505390

  3. Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

    PubMed

    Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

    2014-01-01

    Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge. PMID:24786694

  4. Turbo Processing for Speech Recognition.

    PubMed

    Moon, Todd K; Gunther, Jacob H; Broadus, Cortnie; Hou, Wendy; Nelson, Nils

    2014-01-01

    Speech recognition is a classic example of a human/machine interface, typifying many of the difficulties and opportunities of human/machine interaction. In this paper, speech recognition is used as an example of applying turbo processing principles to the general problem of human/machine interface. Speech recognizers frequently involve a model representing phonemic information at a local level, followed by a language model representing information at a nonlocal level. This structure is analogous to the local (e.g., equalizer) and nonlocal (e.g., error correction decoding) elements common in digital communications. Drawing from the analogy of turbo processing for digital communications, turbo speech processing iteratively feeds back the output of the language model to be used as prior probabilities for the phonemic model. This analogy is developed here, and the performance of this turbo model is characterized by using an artificial language model. Using turbo processing, the relative error rate improves significantly, especially in high-noise settings.

  5. Turbo compound engine

    SciTech Connect

    Okada, M.; Sekiyama, S.

    1988-06-07

    A turbo compound engine is described comprising: an engine having an exhaust gas passage and a crankshaft; a power turbine disposed in the exhaust gas passage so as to recover the exhaust gas energy; driving power transmission means for drivingly connecting the power turbine and the crankshaft so as to transmit the driving power; a fluid passage connected to a portion of the exhaust passage which lies between the power turbine and the engine; and fluid passage switching means for closing the exhaust passage upstream of the fluid passage while opening the fluid passage during exhaust braking.

  6. The LHCb Turbo stream

    NASA Astrophysics Data System (ADS)

    Puig, A.

    2016-07-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015-2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  7. Terahertz dielectric response of photoexcited carriers in Si revealed via single-shot optical-pump and terahertz-probe spectroscopy

    SciTech Connect

    Minami, Yasuo; Horiuchi, Kohei; Masuda, Kaisei; Takeda, Jun; Katayama, Ikufumi

    2015-10-26

    We have demonstrated accurate observations of terahertz (THz) dielectric response due to photoexcited carriers in a Si plate via single-shot optical-pump and THz-probe spectroscopy. In contrast to conventional THz time-domain spectroscopy, this spectroscopic technique allows single-shot detection of the THz response of materials at a given delay time between the pump and THz pulses, thereby sufficiently extending the time interval between the pump pulses. As a result, we can accurately measure the dielectric properties of materials, while avoiding artifacts in the response caused by the accumulation of long-lived photoexcited carriers. Using our single-shot scheme, the transmittance of a Si plate was measured in the range of 0.5–2.5 THz with different pump fluences. Based on a Drude model analysis, the optically induced complex dielectric constant, plasma frequency, and damping rate in the THz region were quantitatively evaluated.

  8. Single-shot 3 × 3 beam grating interferometry for self-imaging free extended range wave front sensing.

    PubMed

    Patorski, Krzysztof; Służewski, Łukasz; Trusiak, Maciej

    2016-09-15

    Crossed grating 3×3 beam lateral shear interferometry for extended range wave front sensing is presented. A Fresnel diffraction pattern of two multiplicatively superimposed linear diffraction gratings each generating three diffraction orders is recorded. A simple solution employs a common crossed binary amplitude Ronchi grating with spatial filtering. Digital processing of a single-shot pattern includes separating multidirectional pairs of orthogonal lateral shear interferograms, retrieving second harmonics of their intensity distribution, and calculating shearing phases. Single-frame automatic fringe pattern processing based on the Hilbert-Huang transform is used for this purpose. Using second harmonics extends the aberration measurement range since they encode self-imaging free two-beam interferograms without contrast modulations. Experimental works corroborate the principle and capabilities of the proposed approach. PMID:27628412

  9. Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation.

    PubMed

    Ji, Xu; Jiang, Lan; Li, Xiaowei; Han, Weina; Liu, Yang; Huang, Qiang; Lu, Yongfeng

    2014-10-10

    Formation of the elliptical-shaped craters on a silicon surface is investigated comprehensively using a single shot of a femtosecond laser. It is observed that the ablation craters are elongated along the major axis of the polarization direction, while their orientation is parallel to the polarization direction. The ablation area grows and the morphology of the craters evolves from an ellipse to nearly a circle with increasing fluence. The underlying physical mechanism is revealed through numerical simulations that are based on the finite-difference time-domain technique. It is suggested that the initially formed craters or surface defects lead to the redistribution of the electric field on the silicon surface, which plays a crucial role in the creation of the elliptical-shaped craters. In addition, the field intensity becomes enhanced along the incident laser polarization direction, which determines the elliptical crater orientations. PMID:25322377

  10. Modelling single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources.

    PubMed

    Loch, R A; Sobierajski, R; Louis, E; Bosgra, J; Bijkerk, F

    2012-12-17

    The single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly used multilayer optics and propose new material combinations selected for a high damage threshold. Our study demonstrates that the damage thresholds of multilayer optics can vary over a large range of incidence fluences and can be as high as several hundreds of mJ/cm(2). This strongly suggests that multilayer mirrors are serious candidates for damage resistant optics. Especially, multilayer optics based on Li(2)O spacers are very promising for use in current and future short-wavelength radiation sources.

  11. Single shot spin readout with a cryogenic high-electron-mobility transistor amplifier at sub-Kelvin temperatures

    DOE PAGES

    Tracy, Lisa A.; Luhman, Dwight R.; Carr, Stephen M.; Bishop, Nathaniel C.; Ten Eyck, Gregory A.; Pluym, Tammy; Wendt, Joel R.; Lilly, Michael P.; Carroll, Malcolm S.

    2016-02-08

    We use a cryogenic high-electron-mobility transistor circuit to amplify the current from a single electron transistor, allowing for demonstration of single shot readout of an electron spin on a single P donor in Si with 100 kHz bandwidth and a signal to noise ratio of ~9. In order to reduce the impact of cable capacitance, the amplifier is located adjacent to the Si sample, at the mixing chamber stage of a dilution refrigerator. For a current gain of ~2.7 x 103 the power dissipation of the amplifier is 13 μW, the bandwidth is ~1.3 MHz, and for frequencies above 300more » kHz the current noise referred to input is ≤ 70 fA/√Hz. Furthermore, with this amplification scheme, we are able to observe coherent oscillations of a P donor electron spin in isotopically enriched 28Si with 96% visibility.« less

  12. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    NASA Astrophysics Data System (ADS)

    Mo, M. Z.; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Sokolowski-Tinten, K.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; Makasyuk, I.; Edstrom, S.; McCormick, D.; Jobe, K.; Hast, C.; Glenzer, S. H.; Wang, X.

    2016-11-01

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.

  13. Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation.

    PubMed

    Ji, Xu; Jiang, Lan; Li, Xiaowei; Han, Weina; Liu, Yang; Huang, Qiang; Lu, Yongfeng

    2014-10-10

    Formation of the elliptical-shaped craters on a silicon surface is investigated comprehensively using a single shot of a femtosecond laser. It is observed that the ablation craters are elongated along the major axis of the polarization direction, while their orientation is parallel to the polarization direction. The ablation area grows and the morphology of the craters evolves from an ellipse to nearly a circle with increasing fluence. The underlying physical mechanism is revealed through numerical simulations that are based on the finite-difference time-domain technique. It is suggested that the initially formed craters or surface defects lead to the redistribution of the electric field on the silicon surface, which plays a crucial role in the creation of the elliptical-shaped craters. In addition, the field intensity becomes enhanced along the incident laser polarization direction, which determines the elliptical crater orientations.

  14. Single-shot 3 × 3 beam grating interferometry for self-imaging free extended range wave front sensing.

    PubMed

    Patorski, Krzysztof; Służewski, Łukasz; Trusiak, Maciej

    2016-09-15

    Crossed grating 3×3 beam lateral shear interferometry for extended range wave front sensing is presented. A Fresnel diffraction pattern of two multiplicatively superimposed linear diffraction gratings each generating three diffraction orders is recorded. A simple solution employs a common crossed binary amplitude Ronchi grating with spatial filtering. Digital processing of a single-shot pattern includes separating multidirectional pairs of orthogonal lateral shear interferograms, retrieving second harmonics of their intensity distribution, and calculating shearing phases. Single-frame automatic fringe pattern processing based on the Hilbert-Huang transform is used for this purpose. Using second harmonics extends the aberration measurement range since they encode self-imaging free two-beam interferograms without contrast modulations. Experimental works corroborate the principle and capabilities of the proposed approach.

  15. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun.

    PubMed

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao; Zhang, Jie; Cao, Jianming

    2014-08-01

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5 MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  16. Single-shot thermometry and OH detection via femtosecond fully resonant electronically enhanced CARS (FREE-CARS).

    PubMed

    Wrzesinski, Paul J; Stauffer, Hans U; Schmidt, Jacob B; Roy, Sukesh; Gord, James R

    2016-05-01

    Femtosecond time-resolved, fully resonant electronically enhanced coherent anti-Stokes Raman scattering (FREE-CARS) spectroscopy, incorporating a two-color excitation scheme, is used to demonstrate selective and sensitive gas-phase detection of the hydroxyl (OH) radical in a reacting flow. Spectral resolution of the emitted FREE-CARS signal allows simultaneous detection of temperature and relative OH mole fraction under single-laser-shot conditions in a laminar ethylene-air flame. By comparison to previously reported OH concentration and temperature measurements, we demonstrate excellent single-shot temperature accuracies (∼2% deviation from adiabatic flame temperature) and precisions (∼2% standard deviation), with simultaneous relative OH concentration measurements that demonstrate high detection sensitivity (100-300 ppm). PMID:27128064

  17. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    DOE PAGES

    Mo, M. Z.; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Sokolowski-Tinten, K.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; et al

    2016-08-04

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 µm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined.more » This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime« less

  18. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun

    SciTech Connect

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao Zhang, Jie; Cao, Jianming

    2014-08-15

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5 MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  19. Transverse single-shot cross-correlation scheme for laser pulse temporal measurement via planar second harmonic generation.

    PubMed

    Wang, B; Cojocaru, C; Krolikowski, W; Sheng, Y; Trull, J

    2016-09-19

    We present a novel single-shot cross-correlation technique based on the analysis of the transversally emitted second harmonic generation in crystals with random distribution and size of anti-parallel nonlinear domains. We implement it to the measurement of ultrashort laser pulses with unknown temporal duration and shape. We optimize the error of the pulse measurement by controlling the incident angle and beam width. As novelty and unlike the other well-known cross correlation schemes, this technique can be implemented for the temporal characterization of pulses over a very wide dynamic range (30 fs-1ps) and wavelengths (800-2200 nm), using the same crystal and without critical angular or temperature alignment. PMID:27661955

  20. Single Shot Coherence Properties of the Free-Electron Laser SACLA in the Hard X-ray Regime

    PubMed Central

    Lehmkühler, Felix; Gutt, Christian; Fischer, Birgit; Schroer, Martin A.; Sikorski, Marcin; Song, Sanghoon; Roseker, Wojciech; Glownia, James; Chollet, Mathieu; Nelson, Silke; Tono, Kensuke; Katayama, Tetsuo; Yabashi, Makina; Ishikawa, Tetsuya; Robert, Aymeric; Grübel, Gerhard

    2014-01-01

    We measured the coherence properties of the free-electron laser SACLA on a single shot basis at an X-ray energy of 8 keV. By analysing small-angle X-ray scattering speckle patterns from colloidal dispersions we found a degree of transverse coherence of βt = 0.79 ± 0.09. Taking detector properties into account, we developed a simulation model in oder to determine the degree of coherence from intensity histograms. Finally we calculated a coherence time of τc = 0.1 fs and a pulse duration of 5.2 fs which corresponds with previous predictions. PMID:24913261

  1. Determination of the pulse duration of an x-ray free electron laser using highly resolved single-shot spectra.

    PubMed

    Inubushi, Yuichi; Tono, Kensuke; Togashi, Tadashi; Sato, Takahiro; Hatsui, Takaki; Kameshima, Takashi; Togawa, Kazuaki; Hara, Toru; Tanaka, Takashi; Tanaka, Hitoshi; Ishikawa, Tetsuya; Yabashi, Makina

    2012-10-01

    We determined the pulse duration of x-ray free electron laser light at 10 keV using highly resolved single-shot spectra, combined with an x-ray free electron laser simulation. Spectral profiles, which were measured with a spectrometer composed of an ultraprecisely figured elliptical mirror and an analyzer flat crystal of silicon (555), changed markedly when we varied the compression strength of the electron bunch. The analysis showed that the pulse durations were reduced from 31 to 4.5 fs for the strongest compression condition. The method, which is readily applicable to evaluate shorter pulse durations, provides a firm basis for the development of femtosecond to attosecond sciences in the x-ray region.

  2. Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser

    PubMed Central

    De Ninno, Giovanni; Gauthier, David; Mahieu, Benoît; Ribič, Primož Rebernik; Allaria, Enrico; Cinquegrana, Paolo; Danailov, Miltcho Bojanov; Demidovich, Alexander; Ferrari, Eugenio; Giannessi, Luca; Penco, Giuseppe; Sigalotti, Paolo; Stupar, Matija

    2015-01-01

    Intense ultrashort X-ray pulses produced by modern free-electron lasers (FELs) allow one to probe biological systems, inorganic materials and molecular reaction dynamics with nanoscale spatial and femtoscale temporal resolution. These experiments require the knowledge, and possibly the control, of the spectro-temporal content of individual pulses. FELs relying on seeding have the potential to produce spatially and temporally fully coherent pulses. Here we propose and implement an interferometric method, which allows us to carry out the first complete single-shot spectro-temporal characterization of the pulses, generated by an FEL in the extreme ultraviolet spectral range. Moreover, we provide the first direct evidence of the temporal coherence of a seeded FEL working in the extreme ultraviolet spectral range and show the way to control the light generation process to produce Fourier-limited pulses. Experiments are carried out at the FERMI FEL in Trieste. PMID:26290320

  3. Sub-10 ns single-shot dynamic recording in holographic polymeric medium by nonlinear absorption using excited state absorption process

    NASA Astrophysics Data System (ADS)

    Kamada, Kenji; Satoh, Kazuyuki; Tanaka, Yoshito

    2016-09-01

    Optical recording by a single shot of an 8 ns laser pulse in a dye-doped holographic polymeric medium was demonstrated with a peak power as low as 71 W at a wavelength of 402 nm. Nonlinear absorption triggered by two-photon absorption and enhanced by the succeeding process allows high-speed recording corresponding to 125 Mbps (3.4 times the recording speed of a Blu-ray Disc). The preformed holographic grating in the medium enhanced the readout signal through diffraction, resulting in a signal-to-noise ratio of about 15 dB. The recording capacity was estimated at ca. 80 GB/side for 100 µm/side by recording 20 layers, but that of over TB/side class would be possible for optical optimization. Theoretically, it can be improved to 10 TB/side for 800 µm/side by recording 400 layers.

  4. Turbo marketing through time compression.

    PubMed

    Kotler, P; Stonich, P J

    1991-01-01

    A host of advantages will flow to companies that learn to make and deliver goods and services faster than their competitors. However, four key questions must be answered to determine if a turbo marketing approach is suitable for your company.

  5. Turbo fluid machinery and diffusers

    NASA Technical Reports Server (NTRS)

    Sakurai, T.

    1984-01-01

    The general theory behind turbo devices and diffusers is explained. Problems and the state of research on basic equations of flow and experimental and measuring methods are discussed. Conventional centrifugation-type compressor and fan diffusers are considered in detail.

  6. Measurement of transient acoustic fields using a single-shot pressure-sensitive paint system.

    PubMed

    Disotell, Kevin J; Gregory, James W

    2011-07-01

    A pressure-sensitive paint (PSP) system capable of measuring high-frequency acoustic fields with non-periodic, acoustic-level pressure changes is described. As an optical measurement technique, PSP provides the experimenter with a global distribution of pressure on a painted surface. To demonstrate frequency response and enhanced sensitivity to pressure changes, a PSP system consisting of a polymer∕ceramic matrix binder with platinum tetra(pentafluorophenyl) porphyrin (PtTFPP) as the oxygen probe was applied to a wall inside an acoustic resonance cavity excited at 1.3 kHz. A data acquisition technique based on the luminescent decay lifetime of the oxygen sensors excited by a single pulse of light afforded the ability to capture instantaneous pressure fields with no phase-averaging. Superimposed wave-like structures were observed with a wavelength corresponding to a 4.7% difference from the theoretical value for a sound wave emanating from the speaker. High sound pressure cases upwards of 145 dB (re 20 μPa) exhibited skewed nodal lines attributed to a nonlinear acoustic field. The lowest sound pressure level of 125.4 dB--corresponding to an amplitude of 52.7 Pa, or approximately 0.05% of standard sea-level atmospheric pressure--showed that the paint could resolve the spatial details of the mode shape at the given resonance condition.

  7. Measurement of transient acoustic fields using a single-shot pressure-sensitive paint system

    NASA Astrophysics Data System (ADS)

    Disotell, Kevin J.; Gregory, James W.

    2011-07-01

    A pressure-sensitive paint (PSP) system capable of measuring high-frequency acoustic fields with non-periodic, acoustic-level pressure changes is described. As an optical measurement technique, PSP provides the experimenter with a global distribution of pressure on a painted surface. To demonstrate frequency response and enhanced sensitivity to pressure changes, a PSP system consisting of a polymer/ceramic matrix binder with platinum tetra(pentafluorophenyl) porphyrin (PtTFPP) as the oxygen probe was applied to a wall inside an acoustic resonance cavity excited at 1.3 kHz. A data acquisition technique based on the luminescent decay lifetime of the oxygen sensors excited by a single pulse of light afforded the ability to capture instantaneous pressure fields with no phase-averaging. Superimposed wave-like structures were observed with a wavelength corresponding to a 4.7% difference from the theoretical value for a sound wave emanating from the speaker. High sound pressure cases upwards of 145 dB (re 20 μPa) exhibited skewed nodal lines attributed to a nonlinear acoustic field. The lowest sound pressure level of 125.4 dB—corresponding to an amplitude of 52.7 Pa, or approximately 0.05% of standard sea-level atmospheric pressure—showed that the paint could resolve the spatial details of the mode shape at the given resonance condition.

  8. Measurement of transient acoustic fields using a single-shot pressure-sensitive paint system.

    PubMed

    Disotell, Kevin J; Gregory, James W

    2011-07-01

    A pressure-sensitive paint (PSP) system capable of measuring high-frequency acoustic fields with non-periodic, acoustic-level pressure changes is described. As an optical measurement technique, PSP provides the experimenter with a global distribution of pressure on a painted surface. To demonstrate frequency response and enhanced sensitivity to pressure changes, a PSP system consisting of a polymer∕ceramic matrix binder with platinum tetra(pentafluorophenyl) porphyrin (PtTFPP) as the oxygen probe was applied to a wall inside an acoustic resonance cavity excited at 1.3 kHz. A data acquisition technique based on the luminescent decay lifetime of the oxygen sensors excited by a single pulse of light afforded the ability to capture instantaneous pressure fields with no phase-averaging. Superimposed wave-like structures were observed with a wavelength corresponding to a 4.7% difference from the theoretical value for a sound wave emanating from the speaker. High sound pressure cases upwards of 145 dB (re 20 μPa) exhibited skewed nodal lines attributed to a nonlinear acoustic field. The lowest sound pressure level of 125.4 dB--corresponding to an amplitude of 52.7 Pa, or approximately 0.05% of standard sea-level atmospheric pressure--showed that the paint could resolve the spatial details of the mode shape at the given resonance condition. PMID:21806232

  9. Single-shot real-time characterization of chirped-pulse amplification systems by spectral phase interferometry for direct electric-field reconstruction.

    PubMed

    Dorrer, C; de Beauvoir, B; Le Blanc, C; Ranc, S; Rousseau, J P; Rousseau, P; Chambaret, J P; Salin, F

    1999-11-15

    We characterize chirped-pulse amplification systems by using spectral phase interferometry for direct electric-field reconstruction. For the first time to the authors' knowledge, single-shot real-time operation has been obtained for this technique, leading to a fast and accurate optimization of these systems.

  10. Single-Shot Charge Readout Using a Cryogenic Heterojunction Bipolar Transistor Preamplifier Inline with a Silicon Single Electron Transistor at Millikelvin Temperatures

    NASA Astrophysics Data System (ADS)

    Curry, Matthew; England, Troy; Wendt, Joel; Pluym, Tammy; Lilly, Michael; Carr, Stephen; Carroll, Malcolm

    Single-shot readout is a requirement for many implementations of quantum information processing. The single-shot readout fidelity is dependent on the signal-to-noise-ratio (SNR) and bandwidth of the readout detection technique. Several different approaches are being pursued to enhance read-out including RF-reflectometry, RF-transmission, parametric amplification, and transistor-based cryogenic preamplification. The transistor-based cryogenic preamplifier is attractive in part because of the reduced experimental complexity compared with the RF techniques. Here we present single-shot charge readout using a cryogenic Heterojunction-Bipolar-Transistor (HBT) inline with a silicon SET charge-sensor at millikelvin temperatures. For the relevant range of HBT DC-biasing, the current gain is 100 to 2000 and the power dissipation is 50 nW to 5 μW, with the microfabricated SET and discrete HBT in an integrated package mounted to the mixing chamber stage of a dilution refrigerator. We experimentally demonstrate a SNR of up to 10 with a bandwidth of 1 MHz, corresponding to a single-shot time-domain charge-sensitivity of approximately 10-4 e / √Hz. This measured charge-sensitivity is comparable to the values reported using the RF techniques. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  11. Single-shot Thomson scattering on argon plasmas created by the Microwave Plasma Torch; evidence for a new plasma class

    NASA Astrophysics Data System (ADS)

    van der Mullen, J. J. A. M.; van de Sande, M. J.; de Vries, N.; Broks, B.; Iordanova, E.; Gamero, A.; Torres, J.; Sola, A.

    2007-10-01

    To determine the fine-structure size of plasmas created by a Microwave Plasma Torch (MPT), single-shot Thomson scattering (TS) measurements were performed. The aim was to find a solution for the long-standing discrepancy between experiments and Global Plasma Models (GPMs). Since these GPMs are based on the assumption that (ambipolar) diffusion is the main loss process for charged particles, the diffusion length and thus the fine-structure size should be known with high precision before an appropriate theory-experiment comparison can be carried out. In order to avoid the effect of blurring, which is created during the accumulation of multi-shot TS signals and which obscures the fine-structures, single-shot measurements are indispensable to determine the diffusion length. The results of the present study reveal that the impression created by multi-shot TS that MPT plasmas resemble stable cones is not (always) correct; instead it is found that the plasmas we investigated are tiny filaments that rotate on the mantle of a virtual cone. However, the fine-structure, especially the thickness, of these filaments is not substantially smaller than that of the virtual cone. By applying the theory-experiment comparison to the filament we found that the disagreement is even worse than what we found for the cone. It is therefore inevitable to conclude that the main proposition of the GPM is incorrect. Apparently the plasma is not diffusive in nature; that is, the main loss process of charged particles is not provided by diffusion but by local chemistry. Swirling in a cool nitrogen-containing environment favors the production of molecular ions such as Ar 2+ and N 2+ inside the plasma filament. The destruction of these molecular ions leads to recombination frequencies that are more than a factor 100 larger than what ambipolar diffusion can provide. Thus we are dealing with another plasma class and it is useful to divide plasmas into diffusive and reactive plasmas. The well

  12. Single-shot Raman spectroscopy and time-resolved reflectivity of a shocked TATB-based explosive

    NASA Astrophysics Data System (ADS)

    Hebert, Philippe; Saint-Amans, Charles; Doucet, Michel; de Resseguier, Thibaut

    2015-06-01

    Single-shot Raman spectroscopy experiments under shockwave loading were performed in order to get information on the initiation mechanisms that can lead to sustained detonation of a TATB-based explosive. Shocks up to 30 GPa were generated using a two-stage laser-driven flyer plate generator. The samples were confined by an optical window and shock pressure was maintained for at least 30 ns. Photon Doppler Velocimetry measurements were performed at the explosive/window interface to determine the shock pressure profile. Raman spectra were recorded as a function of shock pressure and the shifts of the principal modes were compared to static high-pressure measurements performed in a diamond anvil cell. Our shock data indicate the role of temperature effects on the H-bonding network present in TATB. Our Raman spectra also show a progressive extinction of the signal which disappears around 9 GPa. High-speed photography images reveal a simultaneous progressive darkening of the sample surface up to total opacity at 9 GPa. Time-resolved reflectivity measurements under shock compression seem to indicate that this opacity is due to a broadening of the absorption spectrum over the entire visible region.

  13. Single-Shot Scalar-Triplet Measurements in High-Pressure Swirl-Stabilized Flames for Combustion Code Validation

    NASA Technical Reports Server (NTRS)

    Kojima, Jun; Nguyen, Quang-Viet

    2007-01-01

    In support of NASA ARMD's code validation project, we have made significant progress by providing the first quantitative single-shot multi-scalar data from a turbulent elevated-pressure (5 atm), swirl-stabilized, lean direct injection (LDI) type research burner operating on CH4-air using a spatially-resolved pulsed-laser spontaneous Raman diagnostic technique. The Raman diagnostics apparatus and data analysis that we present here were developed over the past 6 years at Glenn Research Center. From the Raman scattering data, we produce spatially-mapped probability density functions (PDFs) of the instantaneous temperature, determined using a newly developed low-resolution effective rotational bandwidth (ERB) technique. The measured 3-scalar (triplet) correlations, between temperature, CH4, and O2 concentrations, as well as their PDF s, also provide a high-level of detail into the nature and extent of the turbulent mixing process and its impact on chemical reactions in a realistic gas turbine injector flame at elevated pressures. The multi-scalar triplet data set presented here provides a good validation case for CFD combustion codes to simulate by providing both average and statistical values for the 3 measured scalars.

  14. Irreversible transformation of ferromagnetic ordered stripe domains in single-shot infrared-pump/resonant-x-ray-scattering-probe experiments

    NASA Astrophysics Data System (ADS)

    Bergeard, Nicolas; Schaffert, Stefan; López-Flores, Víctor; Jaouen, Nicolas; Geilhufe, Jan; Günther, Christian M.; Schneider, Michael; Graves, Catherine; Wang, Tianhan; Wu, Benny; Scherz, Andreas; Baumier, Cédric; Delaunay, Renaud; Fortuna, Franck; Tortarolo, Marina; Tudu, Bharati; Krupin, Oleg; Minitti, Michael P.; Robinson, Joe; Schlotter, William F.; Turner, Joshua J.; Lüning, Jan; Eisebitt, Stefan; Boeglin, Christine

    2015-02-01

    The evolution of a magnetic domain structure upon excitation by an intense, femtosecond infrared (IR) laser pulse has been investigated using single-shot based time-resolved resonant x-ray scattering at the x-ray free electron laser LCLS. A well-ordered stripe domain pattern as present in a thin CoPd alloy film has been used as a prototype magnetic domain structure for this study. The fluence of the IR laser pump pulse was sufficient to lead to an almost complete quenching of the magnetization within the ultrafast demagnetization process taking place within the first few hundreds of femtoseconds following the IR laser pump pulse excitation. On longer time scales this excitation gave rise to subsequent irreversible transformations of the magnetic domain structure. Under our specific experimental conditions, it took about 2 ns before the magnetization started to recover. After about 5 ns the previously ordered stripe domain structure had evolved into a disordered labyrinth domain structure. Surprisingly, we observe after about 7 ns the occurrence of a partially ordered stripe domain structure reoriented into a novel direction. It is this domain structure in which the sample's magnetization stabilizes as revealed by scattering patterns recorded long after the initial pump-probe cycle. Using micromagnetic simulations we can explain this observation based on changes of the magnetic anisotropy going along with heat dissipation in the film.

  15. Single-shot T1 mapping of the corpus callosum: a rapid characterization of fiber bundle anatomy.

    PubMed

    Hofer, Sabine; Wang, Xiaoqing; Roeloffs, Volkert; Frahm, Jens

    2015-01-01

    Using diffusion-tensor magnetic resonance imaging and fiber tractography the topographic organization of the human corpus callosum (CC) has been described to comprise five segments with fibers projecting into prefrontal (I), premotor and supplementary motor (II), primary motor (III), and primary sensory areas (IV), as well as into parietal, temporal, and occipital cortical areas (V). In order to more rapidly characterize the underlying anatomy of these segments, this study used a novel single-shot T1 mapping method to quantitatively determine T1 relaxation times in the human CC. A region-of-interest analysis revealed a tendency for the lowest T1 relaxation times in the genu and the highest T1 relaxation times in the somatomotor region of the CC. This observation separates regions dominated by myelinated fibers with large diameters (somatomotor area) from densely packed smaller axonal bundles (genu) with less myelin. The results indicate that characteristic T1 relaxation times in callosal profiles provide an additional means to monitor differences in fiber anatomy, fiber density, and gray matter in respective neocortical areas. In conclusion, rapid T1 mapping allows for a characterization of the axonal architecture in an individual CC in less than 10 s. The approach emerges as a valuable means for studying neocortical brain anatomy with possible implications for the diagnosis of neurodegenerative processes.

  16. Cavity Exciton-Polariton mediated, Single-Shot Quantum Non-Demolition measurement of a Quantum Dot Electron Spin

    NASA Astrophysics Data System (ADS)

    Puri, Shruti; McMahon, Peter; Yamamoto, Yoshihisa

    2014-03-01

    The quantum non-demolition (QND) measurement of a single electron spin is of great importance in measurement-based quantum computing schemes. The current single-shot readout demonstrations exhibit substantial spin-flip backaction. We propose a QND readout scheme for quantum dot (QD) electron spins in Faraday geometry, which differs from previous proposals and implementations in that it relies on a novel physical mechanism: the spin-dependent Coulomb exchange interaction between a QD spin and optically-excited quantum well (QW) microcavity exciton-polaritons. The Coulomb exchange interaction causes a spin-dependent shift in the resonance energy of the polarized polaritons, thus causing the phase and intensity response of left circularly polarized light to be different to that of the right circularly polarized light. As a result the QD electron's spin can be inferred from the response to a linearly polarized probe. We show that by a careful design of the system, any spin-flip backaction can be eliminated and a QND measurement of the QD electron spin can be performed within a few 10's of nanoseconds with fidelity 99:95%. This improves upon current optical QD spin readout techniques across multiple metrics, including fidelity, speed and scalability. National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan.

  17. Single-shot quantum nondemolition measurement of a quantum-dot electron spin using cavity exciton-polaritons

    NASA Astrophysics Data System (ADS)

    Puri, Shruti; McMahon, Peter L.; Yamamoto, Yoshihisa

    2014-10-01

    We propose a scheme to perform single-shot quantum nondemolition (QND) readout of the spin of an electron trapped in a semiconductor quantum dot (QD). Our proposal relies on the interaction of the QD electron spin with optically excited, quantum well (QW) microcavity exciton-polaritons. The spin-dependent Coulomb exchange interaction between the QD electron and cavity polaritons causes the phase and intensity response of left circularly polarized light to be different than that of right circularly polarized light, in such a way that the QD electron's spin can be inferred from the response to a linearly polarized probe reflected or transmitted from the cavity. We show that with careful device design it is possible to essentially eliminate spin-flip Raman transitions. Thus a QND measurement of the QD electron spin can be performed within a few tens of nanoseconds with fidelity ˜99.95%. This improves upon current optical QD spin readout techniques across multiple metrics, including speed and scalability.

  18. Flexible Low-power SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout

    NASA Astrophysics Data System (ADS)

    England, Troy; Lilly, Michael; Curry, Matthew; Carr, Stephen; Carroll, Malcolm

    Fast, low-power quantum state readout is one of many challenges facing quantum information processing. Single electron transistors (SETs) are potentially fast, sensitive detectors for performing spin readout of electrons bound to Si:P donors. From a circuit perspective, however, their output impedance and nonlinear conductance are ill suited to drive the parasitic capacitance of coaxial conductors used in cryogenic environments, necessitating a cryogenic amplification stage. We will introduce two new amplifier topologies that provide excellent gain versus power tradeoffs using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). The AC HBT allows in-situ adjustment of power dissipation during an experiment and can provide gain in the millikelvin temperature regime while dissipating less than 500 nW. The AC Current Amplifier maximizes gain at nearly 800 A/A. We will also show results of using these amplifiers with SETs at 4 K. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000. Flexible Low-power SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout.

  19. Functional imaging with Turbo-CASL: transit time and multislice imaging considerations.

    PubMed

    Lee, Gregory R; Hernandez-Garcia, Luis; Noll, Douglas C

    2007-04-01

    The optimal use of turbo continuous arterial spin labeling (Turbo-CASL) for functional imaging in the presence of activation-induced transit time (TT) changes was investigated. Functional imaging of a bilateral finger-tapping task showed improved sensitivity for Turbo-CASL as compared to traditional CASL techniques for four of six subjects when scanned at an appropriate repetition time (TR). Both experimental and simulation results suggest that for optimal functional sensitivity with Turbo-CASL, the pulse TR should be set to a value that is 100-200 ms less than the resting-state TT. Simulations were also run to demonstrate the differences in TT sensitivity of different slices within a multislice acquisition, and the signal loss that is expected as the number of slices is increased. Despite the lower baseline ASL signal provided by the Turbo-CASL acquisition, one can achieve equal or improved functional sensitivity due in part to the signal enhancement that accompanies the decrease in TT upon activation. Turbo-CASL is thus a promising technique for functional ASL at higher temporal resolution.

  20. Turbo marketing through time compression.

    PubMed

    Kotler, P; Stonich, P J

    1991-01-01

    A host of advantages will flow to companies that learn to make and deliver goods and services faster than their competitors. However, four key questions must be answered to determine if a turbo marketing approach is suitable for your company. PMID:10114516

  1. A Virus in Turbo Pascal.

    ERIC Educational Resources Information Center

    Teleky, Heidi Ann; And Others

    1993-01-01

    Addresses why the authors feel it is not inappropriate to teach about viruses in the how-to, hands-on fashion. Identifies the special features of Turbo Pascal that have to be used for the creation of an effective virus. Defines virus, derives its structure, and from this structure is derived the implemented virus. (PR)

  2. Electrical performance characterisation of single-shot switches in high speed, high voltage and high current applications

    NASA Astrophysics Data System (ADS)

    Podlesak, Michael

    1994-08-01

    The electrical performance characteristics of single-shot closing switches for slapper detonator applications were measured via the discharge of a low impedance transmission line. The switch performance, characterized by its time-dependent resistance behavior, could not be assessed via the more conventional methods of measurement because of high bandwidth requirements at comparatively high levels of voltage and current. Hence, an alternative technique based on a transmission line discharge was devised in which the time-dependent resistance of the switch can be determined from the measured current waveform of the switch, the initial open circuit voltage and the transmission line parameters only. Under certain conditions a simple lossless transmission line formula is sufficient for the calculation of the switch resistance waveform. However, if the transmission line losses cannot be neglected, a correction can be readily implemented through numerical signal processing. The bandwidth of this technique is limited to the bandwidth of the switch current measurement only, which proved to be particularly useful for the measurement of switches for slapper detonator applications where inductive pick-up noise in the switch voltage waveform is large and where high voltage probes of sufficiently high bandwidth are not readily available. In this report, both numerically simulated and experimental examples are given, together with the method of calculation of switch resistance which takes into account practical transmission line losses. It was found that best results are obtained if the magnitude of the switch resistance is of a similar order as the characteristic impedance of the transmission line, or higher.

  3. Feasibility study of a single-shot 3D electron bunch shape monitor with an electro-optic sampling technique

    NASA Astrophysics Data System (ADS)

    Okayasu, Yuichi; Tomizawa, Hiromitsu; Matsubara, Shinichi; Kumagai, Noritaka; Maekawa, Akira; Uesaka, Mitsuru; Ishikawa, Tetsuya

    2013-05-01

    We developed a three-dimensional electron bunch charge distribution (3D-BCD) monitor with single-shot detection, and a spectral decoding based electro-optic (EO) sampling technique for a nondestructive monitor enables real-time reconstruction of the three-dimensional distribution of a bunch charge. We realized three goals by simultaneously probing a number of Pockels EO crystals that surround the electron beam axis with hollow and radial polarized laser pulses. First, we performed a feasibility test as a simple case of a 3D-BCD monitor probing two ZnTe crystals as EO detectors installed on the opposite angle to the electron beam axis and confirmed that we simultaneously obtained both EO signals. Since the adopted hollow probe laser pulse is not only radially polarized but also temporally shifted azimuthally, some disorders in the radial polarization distribution of such a laser pulse were numerically analyzed with a plane-wave expansion method. Based on the above investigations, the 3D-BCD monitor is feasible both in experimental and numerical estimations. Furthermore, we previously developed a femtosecond response organic crystal as a Pockels EO detector and a broadband probe laser (≥350nm in FWHM); the 3D-BCD monitor realizes 30- to 40-fs (FWHM) temporal resolution. Eventually, the monitor is expected to be equipped in such advanced accelerators as XFEL to measure and adjust the electron bunch charge distribution in real time. The 3D-BCD measurement works as a critical tool to provide feedback to seeded FELs.

  4. Demonstration of Single-Shot Picosecond Time-Resolved MeV Electron Imaging Using a Compact Permanent Magnet Quadrupole Based Lens

    NASA Astrophysics Data System (ADS)

    Cesar, D.; Maxson, J.; Musumeci, P.; Sun, Y.; Harrison, J.; Frigola, P.; O'Shea, F. H.; To, H.; Alesini, D.; Li, R. K.

    2016-07-01

    We present the results of an experiment where a short focal length (˜1.3 cm ), permanent magnet electron lens is used to image micron-size features (of a metal sample) with a single shot from an ultrahigh brightness picosecond-long 4 MeV electron beam emitted by a radio-frequency photoinjector. Magnification ratios in excess of 30 × were obtained using a triplet of compact, small gap (3.5 mm), Halbach-style permanent magnet quadrupoles with nearly 600 T /m field gradients. These results pave the way towards single-shot time-resolved electron microscopy and open new opportunities in the applications of high brightness electron beams.

  5. Demonstration of Single-Shot Picosecond Time-Resolved MeV Electron Imaging Using a Compact Permanent Magnet Quadrupole Based Lens.

    PubMed

    Cesar, D; Maxson, J; Musumeci, P; Sun, Y; Harrison, J; Frigola, P; O'Shea, F H; To, H; Alesini, D; Li, R K

    2016-07-01

    We present the results of an experiment where a short focal length (∼1.3  cm), permanent magnet electron lens is used to image micron-size features (of a metal sample) with a single shot from an ultrahigh brightness picosecond-long 4 MeV electron beam emitted by a radio-frequency photoinjector. Magnification ratios in excess of 30× were obtained using a triplet of compact, small gap (3.5 mm), Halbach-style permanent magnet quadrupoles with nearly 600  T/m field gradients. These results pave the way towards single-shot time-resolved electron microscopy and open new opportunities in the applications of high brightness electron beams. PMID:27447510

  6. In vivo single-shot three-dimensionally localized multiple quantum spectroscopy of GABA in the human brain with improved spectral selectivity

    NASA Astrophysics Data System (ADS)

    Choi, In-Young; Lee, Sang-Pil; Shen, Jun

    2005-01-01

    A single-shot multiple quantum filtering method is developed that uses two double-band frequency selective pulses for enhanced spectral selectivity in combination with a slice-selective 90°, a slice-selective universal rotator 90°, and a spectral-spatial pulse composed of two slice-selective universal rotator 45° pulses for single-shot three-dimensional localization. The use of this selective multiple quantum filtering method for C3 and C4 methylene protons of GABA resulted in improved spectral selectivity for GABA and effective suppression of overlapping signals such as creatine and glutathione in each single scan, providing reliable measurements of the GABA doublet in all subjects. The concentration of GABA was measured to be 0.7 ± 0.2 μmol/g (means ± SD, n = 15) in the fronto-parietal region of the human brain in vivo.

  7. Stopping Rules for Turbo Decoders

    NASA Astrophysics Data System (ADS)

    Matache, A.; Dolinar, S.; Pollara, F.

    2000-04-01

    Decoders for turbo codes are iterative in nature, i.e., they have to perform a certain number of iterations before reaching a satisfactory degree of confidence regarding a frame to be decoded. Until now standard turbo decoders have used a fixed number of iterations. In this article, we propose some simple "stopping rules" that can be used to reduce the average number of iterations. This technique offers a trade-off between speed and performance and can provide a significant increase in the average decoding speed while not sacrificing decoder performance. We tested several types of stopping rules for turbo decoders. One type is based on comparing decoded bits (hard bit decisions) with previous decoded bits; a second type is based on comparing reliabilities (soft bit decisions) with a threshold; and a third type uses a cyclic redundancy check (CRC) code applied to hard decoded bits. We simulated turbo decoder performance using these rules (including several variations of t he first two types) and further required that the decoder cease after 20 iterations if the stopping rule is not yet satisfied. Specifically, we analyzed the decoder-error rates and the average number of iterations for each rule. We found that the average number of iterations was roughly between 4 and 7 for a bit signal-to-noise ratio, E_b/N_0, near the "waterfall" threshold, as compared with the 10 fixed iterations used by the current turbo decoder. In addition, the resulting error rates were noticeably lower than those for 10 fixed iterations, and in fact were very nearly equal to the error rates achieved by a decoder using 20 fixed iterations.

  8. Self-acousto-optic modulation and orthogonality violation in the transverse modes of a broad-area Nd-doped yttrium-aluminum-garnet single-shot laser

    SciTech Connect

    Soler Rus, M. Odin; Cabrera-Granado, E.; Guerra Perez, J. M.

    2011-05-15

    Self-acousto-optic Raman-Nath modulation and nonorthogonal transversal modes are found in a broad-area Nd:YAG single-shot laser. The device is free from the thermal-induced effects previously related to orthogonality violation and the acousto-optic modulation comes from a shock wave produced by the discharge of the flash lamps that optically pump the laser. The experimental findings are reproduced by a general model of a class B laser.

  9. Effects of the energy-separation filter on the performance of each detector layer in the sandwich detector for single-shot dual-energy imaging

    NASA Astrophysics Data System (ADS)

    Kim, J.; Kim, D. W.; Kam, S.; Park, E.; Youn, H.; Kim, H. K.

    2016-02-01

    A novel sandwich-style single-shot detector has been built by stacking two indirect-conversion flat-panel detectors for preclinical dual-energy mouse imaging. Although this single-shot method is more immune to motion artifacts compared with the conventional dual-shot method (i.e., fast kVp switching), it may suffer from reduced image quality because of poor spectral separation between the two detectors. Spectral separation can be improved by using an intermediate filter between the two detector layers. Adversely, the filter reduces the number of x-ray photons reaching the rear detector, hence probably increasing image noise. For a better design and practical use of the sandwich detector for single-shot dual-energy imaging, imaging performances of each detector layer in the sandwich detector are investigated for various spectral-separation extents and applied tube voltages. The imaging performances include the modulation-transfer function, the Wiener noise-power spectrum, and the detective quantum efficiency. According to the experimental results, impacts of the intermediate filter on the imaging performances of each detector layer are marginal. The detailed experimental results are shown in this study.

  10. Single-shot single-voxel lactate measurements using FOCI-LASER and a multiple-quantum filter.

    PubMed

    Payne, Geoffrey S; deSouza, Nandita M; Messiou, Christina; Leach, Martin O

    2015-04-01

    Measurement of tissue lactate using (1) H MRS is often confounded by overlap with intense lipid signals at 1.3 ppm. Single-voxel localization using PRESS is also compromised by the large chemical shift displacement between voxels for the 4.1 ppm (-CH) resonance and the 1.3 ppm -CH3 resonance, leading to subvoxels with signals of opposite phase and hence partial signal cancellation. To reduce the chemical shift displacement to negligible proportions, a modified semi-LASER sequence was written ("FOCI-LASER", abbreviated as fLASER) using FOCI pulses to permit high RF bandwidth even with the limited RF amplitude characteristic of clinical MRI scanners. A further modification, MQF-fLASER, includes a selective multiple-quantum filter to detect lactate and reject lipid signals. The sequences were implemented on a Philips 3 T Achieva TX system. In a solution of brain metabolites fLASER lactate signals were 2.7 times those of PRESS. MQF-fLASER lactate was 47% of fLASER (the theoretical maximum is 50%) but still larger than PRESS lactate. In oil, the main 1.3 ppm lipid peak was suppressed to less than 1%. Enhanced suppression was possible using increased gradient durations. The minimum detectable lactate concentration was approximately 0.5 mM. Coherence selection gradients needed to be at the magic angle to avoid large water signals derived from intermolecular multiple-quantum coherences. In pilot patient measurements, lactate peaks were often observed in brain tumours, but not in cervix tumours; lipids were effectively suppressed. In summary, compared with PRESS, the fLASER sequence yields greatly superior sensitivity for direct detection of lactate (and equivalent sensitivity for other metabolites), while the single-voxel single-shot MQF-fLASER sequence surpasses PRESS for lactate detection while eliminating substantial signals from lipids. This sequence will increase the potential for in vivo lactate measurement as a biomarker in targeted anti-cancer treatments as well as

  11. A grating-based single-shot x-ray phase contrast and diffraction method for in vivo imaging

    SciTech Connect

    Bennett, Eric E.; Kopace, Rael; Stein, Ashley F.; Wen Han

    2010-11-15

    Purpose: The purpose of this study is to develop a single-shot version of the grating-based phase contrast x-ray imaging method and demonstrate its capability of in vivo animal imaging. Here, the authors describe the principle and experimental results. They show the source of artifacts in the phase contrast signal and optimal designs that minimize them. They also discuss its current limitations and ways to overcome them. Methods: A single lead grid was inserted midway between an x-ray tube and an x-ray camera in the planar radiography setting. The grid acted as a transmission grating and cast periodic dark fringes on the camera. The camera had sufficient spatial resolution to resolve the fringes. Refraction and diffraction in the imaged object manifested as position shifts and amplitude attenuation of the fringes, respectively. In order to quantify these changes precisely without imposing a fixed geometric relationship between the camera pixel array and the fringes, a spatial harmonic method in the Fourier domain was developed. The level of the differential phase (refraction) contrast as a function of hardware specifications and device geometry was derived and used to guide the optimal placement of the grid and object. Both ex vivo and in vivo images of rodent extremities were collected to demonstrate the capability of the method. The exposure time using a 50 W tube was 28 s. Results: Differential phase contrast images of glass beads acquired at various grid and object positions confirmed theoretical predictions of how phase contrast and extraneous artifacts vary with the device geometry. In anesthetized rats, a single exposure yielded artifact-free images of absorption, differential phase contrast, and diffraction. Differential phase contrast was strongest at bone-soft tissue interfaces, while diffraction was strongest in bone. Conclusions: The spatial harmonic method allowed us to obtain absorption, differential phase contrast, and diffraction images, all from a

  12. Single-shot Zeff dense plasma diagnostic through simultaneous refraction and attenuation measurements with a Talbot–Lau x-ray moiré deflectometer

    SciTech Connect

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2015-03-23

    The Talbot–Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n = 1 - δ + iβ of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both δ and β, which are directly related to the electron density ne and the attenuation coefficient μ, respectively. Since δ and β depend on the effective atomic number Zeff, a map can be obtained from the ratio between phase and absorption images acquired in a single shot. The Talbot–Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Zeff values of test objects within the 4–12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Zeff mapping of objects does not require previous knowledge of sample length or shape. The determination of Zeff from refraction and attenuation measurements with Moiré deflectometry could be of high interest to various domains of HED research, such as shocked materials and ICF experiments, as well as material science and NDT.

  13. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Hering, P.; Brown, S. B.; Curry, C.; Tsui, Y. Y.; Glenzer, S. H.

    2016-11-01

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  14. Wavefront analysis of nonlinear self-amplified spontaneous-emission free-electron laser harmonics in the single-shot regime.

    PubMed

    Bachelard, R; Mercère, P; Idir, M; Couprie, M-E; Labat, M; Chubar, O; Lambert, G; Zeitoun, Ph; Kimura, H; Ohashi, H; Higashiya, A; Yabashi, M; Nagasono, M; Hara, T; Ishikawa, T

    2011-06-10

    The single-shot spatial characteristics of the vacuum ultraviolet self-amplified spontaneous emission of a free electron laser (FEL) is measured at different stages of amplification up to saturation with a Hartmann wavefront sensor. We show that the fundamental radiation at 61.5 nm tends towards a single-mode behavior as getting closer to saturation. The measurements are found in good agreement with simulations and theory. A near diffraction limited wavefront was measured. The analysis of Fresnel diffraction through the Hartmann wavefront sensor hole array also provides some further insight for the evaluation of the FEL transverse coherence, of high importance for various applications.

  15. Pulse shape measurements using single shot-frequency resolved optical gating for high energy (80 J) short pulse (600 fs) laser

    SciTech Connect

    Palaniyappan, S.; Johnson, R.; Shimada, T.; Gautier, D. C.; Letzring, S.; Offermann, D. T.; Fernandez, J. C.; Shah, R. C.; Jung, D.; Hegelich, B. M.; Hoerlein, R.

    2010-10-15

    Relevant to laser based electron/ion accelerations, a single shot second harmonic generation frequency resolved optical gating (FROG) system has been developed to characterize laser pulses (80 J, {approx}600 fs) incident on and transmitted through nanofoil targets, employing relay imaging, spatial filter, and partially coated glass substrates to reduce spatial nonuniformity and B-integral. The device can be completely aligned without using a pulsed laser source. Variations of incident pulse shape were measured from durations of 613 fs (nearly symmetric shape) to 571 fs (asymmetric shape with pre- or postpulse). The FROG measurements are consistent with independent spectral and autocorrelation measurements.

  16. Single-shot analytical assay based on graphene-oxide-modified surface acoustic wave biosensor for detection of single-nucleotide polymorphisms.

    PubMed

    Liu, Xiang; Wang, Jia-Ying; Mao, Xiao-Bing; Ning, Yong; Zhang, Guo-Jun

    2015-09-15

    The combination of a surface acoustic wave (SAW) biosensor with graphene oxide (GO) provides a promising perspective for detecting DNA mutation. The GO-modified SAW biosensor was prepared by conjugating GO onto the SAW chip surface via electrostatic interaction. Afterward, the probe was immobilized on the GO surface, and detection of DNA mutation was realized by hybridization. The hybridization with a variety of targets would yield different mass and conformational changes on the chip surface, causing the different SAW signals in real time. A total of 137 clinical samples were detected by a single-shot analytical assay based on GO-modified SAW biosensor and direct sequencing in parallel. The diagnostic performance (both sensitivity and specificity) of the assay was evaluated with the direct sequencing as a reference testing method. The phase-shift value of three genotypes in 137 clinical samples was significantly different (p < 0.001). Furthermore, testing of diagnostic performance yielded diagnostic sensitivity and specificity of 100% and 88.6% for identifying CT and CC genotype, 98.0% and 96.2% for identifying CT and TT genotype, respectively. The single-shot analytical assay based on the GO-modified SAW biosensor could be exploited as a potential useful tool to identify CYP2D6*10 polymorphisms in clinical practice of personalized medicine.

  17. Drizo protects turbo expander plant

    SciTech Connect

    Frazier, C.W.; Force, J.E.

    1982-01-01

    A triethylene glycol (TEG) unit using Dow's Drizo technology in front of processes was installed in a turbo expander plant owned by Valero Hydrocarbons, San Antonio, Texas. The TEG unit was placed in the process because methanol consumption had run higher than design conditions had predicted; gas flow rates and water content varied widely; and the gas was found to be contaminated considerably with iron sulfide. The TEG unit optimized gas processing by reducing the water content of gas to the system, accepting variable gas flow and water content to smooth out feed gas quality, removing iron sulfide and other contaminants before processing, and being amenable to conversion from other equipment already in existence at other Valero plant locations. The TEG Drizo process provides an azeotropic agent injected into the hot glycol, and the glycol solution is used to reduce residual water content of gas. Details of the equipment and process conversion are given.

  18. Turbo-Brayton Power Converter

    NASA Technical Reports Server (NTRS)

    Breedlove, Jeffrey

    2015-01-01

    Future NASA space missions will require advanced thermal-to-electric power converters that are reliable, efficient, and lightweight. Creare, LLC, is developing a turbo-Brayton power converter that offers high efficiency and specific power. The converter employs gas bearings to provide maintenance free, long-life operation. Discrete components can be packaged to fit optimally with other subsystems, and the converter's continuous gas flow can communicate directly with remote heat sources and heat rejection surfaces without the need for ancillary heat-transfer components and intermediate flow loops. Creare has completed detailed analyses, trade studies, fabrication trials, and preliminary designs for the components and converter assembly. The company is fabricating and testing a breadboard converter.

  19. Cohen's weighted kappa with Turbo Pascal (FORTRAN).

    PubMed

    Reed, J F; Reed, J J

    1992-07-01

    A microcomputer based Turbo Pascal and FORTRAN program for Cohen's weighted kappa (kappa w) is given. Three clinical applications for kappa w are also presented. A typical data file, the Pascal and FORTRAN program listing and corresponding output are given.

  20. Single-Shot Measurement of Temporally-Dependent Polarization State of Femtosecond Pulses by Angle-Multiplexed Spectral-Spatial Interferometry.

    PubMed

    Lin, Ming-Wei; Jovanovic, Igor

    2016-01-01

    We demonstrate that temporally-dependent polarization states of ultrashort laser pulses can be reconstructed in a single shot by use of an angle-multiplexed spatial-spectral interferometry. This is achieved by introducing two orthogonally polarized reference pulses and interfering them with an arbitrarily polarized ultrafast pulse under measurement. A unique calibration procedure is developed for this technique which facilitates the subsequent polarization state measurements. The accuracy of several reconstructed polarization states is verified by comparison with that obtained from an analytic model that predicts the polarization state on the basis of its method of production. Laser pulses with mJ-level energies were characterized via this technique, including a time-dependent polarization state that can be used for polarization-gating of high-harmonic generation for production of attosecond pulses. PMID:27596951

  1. Strategies to improve phase-stability of ultrafast swept source optical coherence tomography for single shot imaging of transient mechanical waves at 16 kHz frame rate

    NASA Astrophysics Data System (ADS)

    Song, Shaozhen; Wei, Wei; Hsieh, Bao-Yu; Pelivanov, Ivan; Shen, Tueng T.; O'Donnell, Matthew; Wang, Ruikang K.

    2016-05-01

    We present single-shot phase-sensitive imaging of propagating mechanical waves within tissue, enabled by an ultrafast optical coherence tomography (OCT) system powered by a 1.628 MHz Fourier domain mode-locked (FDML) swept laser source. We propose a practical strategy for phase-sensitive measurement by comparing the phases between adjacent OCT B-scans, where the B-scan contains a number of A-scans equaling an integer number of FDML buffers. With this approach, we show that micro-strain fields can be mapped with ˜3.0 nm sensitivity at ˜16 000 fps. The system's capabilities are demonstrated on porcine cornea by imaging mechanical wave propagation launched by a pulsed UV laser beam, promising non-contact, real-time, and high-resolution optical coherence elastography.

  2. Single-Shot Measurement of Temporally-Dependent Polarization State of Femtosecond Pulses by Angle-Multiplexed Spectral-Spatial Interferometry

    PubMed Central

    Lin, Ming-Wei; Jovanovic, Igor

    2016-01-01

    We demonstrate that temporally-dependent polarization states of ultrashort laser pulses can be reconstructed in a single shot by use of an angle-multiplexed spatial-spectral interferometry. This is achieved by introducing two orthogonally polarized reference pulses and interfering them with an arbitrarily polarized ultrafast pulse under measurement. A unique calibration procedure is developed for this technique which facilitates the subsequent polarization state measurements. The accuracy of several reconstructed polarization states is verified by comparison with that obtained from an analytic model that predicts the polarization state on the basis of its method of production. Laser pulses with mJ-level energies were characterized via this technique, including a time-dependent polarization state that can be used for polarization-gating of high-harmonic generation for production of attosecond pulses. PMID:27596951

  3. Single-Shot Measurement of Temporally-Dependent Polarization State of Femtosecond Pulses by Angle-Multiplexed Spectral-Spatial Interferometry

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Wei; Jovanovic, Igor

    2016-09-01

    We demonstrate that temporally-dependent polarization states of ultrashort laser pulses can be reconstructed in a single shot by use of an angle-multiplexed spatial-spectral interferometry. This is achieved by introducing two orthogonally polarized reference pulses and interfering them with an arbitrarily polarized ultrafast pulse under measurement. A unique calibration procedure is developed for this technique which facilitates the subsequent polarization state measurements. The accuracy of several reconstructed polarization states is verified by comparison with that obtained from an analytic model that predicts the polarization state on the basis of its method of production. Laser pulses with mJ-level energies were characterized via this technique, including a time-dependent polarization state that can be used for polarization-gating of high-harmonic generation for production of attosecond pulses.

  4. Single Shot Spatial and Temporal Coherence Properties of the SLAC Linac Coherent Light Source in the Hard X-Ray Regime

    NASA Astrophysics Data System (ADS)

    Gutt, C.; Wochner, P.; Fischer, B.; Conrad, H.; Castro-Colin, M.; Lee, S.; Lehmkühler, F.; Steinke, I.; Sprung, M.; Roseker, W.; Zhu, D.; Lemke, H.; Bogle, S.; Fuoss, P. H.; Stephenson, G. B.; Cammarata, M.; Fritz, D. M.; Robert, A.; Grübel, G.

    2012-01-01

    We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time τc=(2.0±1.0)fs. The data suggest a mean x-ray pulse duration of (29±14)fs behind the monochromator for (100±14)fs long electron pulses.

  5. Toward single-shot pure-shift solution 1H NMR by trains of BIRD-based homonuclear decoupling

    NASA Astrophysics Data System (ADS)

    Lupulescu, Adonis; Olsen, Gregory L.; Frydman, Lucio

    2012-05-01

    Achieving homonuclear 1H decoupling remains one of the key challenges in liquid-state NMR. Such spectra would endow a variety of organic and analytical applications with an increased resolution, and would ideally do so even in a one-dimensional format. A number of parallel efforts aimed at achieving this goal using two-dimensional acquisitions have been proposed; approaches demonstrated over recent years include, among others, new modes for achieving purely-absorptive J spectroscopy, the use of spatially-selective manipulations, and exploiting the natural spin dilution afforded by heteronuclei. The present study relies on the latter approach, and explores the use of BIRD pulses distinguishing between protons bonded to 13C from those bonded to 12C, to achieve homonuclear decoupling in a continuous 1D scan. Studies on several representative compounds demonstrate that this goal can be implemented in a robust format, provided that suitable care is also taken to suppress unwanted coherences, of making all manipulations sufficiently broad-banded, and to provide adequate heteronuclear decoupling of the targeted protons. Dependable homonuclear decoupling performance can then be achieved, with minimal line width, fine-tuning, and sensitivity penalties.

  6. An Interactive Concatenated Turbo Coding System

    NASA Technical Reports Server (NTRS)

    Liu, Ye; Tang, Heng; Lin, Shu; Fossorier, Marc

    1999-01-01

    This paper presents a concatenated turbo coding system in which a Reed-Solomon outer code is concatenated with a binary turbo inner code. In the proposed system, the outer code decoder and the inner turbo code decoder interact to achieve both good bit error and frame error performances. The outer code decoder helps the inner turbo code decoder to terminate its decoding iteration while the inner turbo code decoder provides soft-output information to the outer code decoder to carry out a reliability-based soft- decision decoding. In the case that the outer code decoding fails, the outer code decoder instructs the inner code decoder to continue its decoding iterations until the outer code decoding is successful or a preset maximum number of decoding iterations is reached. This interaction between outer and inner code decoders reduces decoding delay. Also presented in the paper are an effective criterion for stopping the iteration process of the inner code decoder and a new reliability-based decoding algorithm for nonbinary codes.

  7. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  8. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  9. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  10. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  11. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  12. Development of single shot soft x-ray contact microscopy system for nano-scale dynamics measurement of living biological specimen

    NASA Astrophysics Data System (ADS)

    Kishimoto, Maki; Kado, Masataka; Ishino, Masahiko; Tamotsu, Satoshi; Yasuda, Keiko; Shinohara, Kunio

    2012-07-01

    We have been developing a picosecond single shot soft x-ray contact microscopy system for observing the nanometer-scale inner structure of the living biological specimen in a hydrated condition. The microscopy system consists of an intense IR pump laser system for generating laser-induced plasma as a soft x-ray source and x-ray microscope chamber. The pump laser system employs OPCPA (Optical Parametric Chirped Pulse Amplification) technique to obtain a high contrast pump laser pulse, and we can generate water-window x-rays effectively by combining it to an ultra-thin metal target. The x-ray microscope chamber is composed of a vacuum chamber, a focusing lens, a metal film target, an in-vacuum type sample holder. The pump laser pulse is focused on the metal film target with a focusing lens. The soft x-rays from the laser-induced plasma illuminates bio-specimens on the PMMA photo resist set in the in-vacuum sample holder. The photo resist is developed and the x-ray transmission image recorded on the photo resist is read out by AFM. We took x-ray images of hydrated Leydig cells from mouse testicle and demonstrated that the developed x-ray microscopy system has a spatial resolution of about 100 nm.

  13. Single-shot readout and relaxation of singlet and triplet states in exchange-coupled 31P electron spins in silicon.

    PubMed

    Dehollain, Juan P; Muhonen, Juha T; Tan, Kuan Y; Saraiva, Andre; Jamieson, David N; Dzurak, Andrew S; Morello, Andrea

    2014-06-13

    We present the experimental observation of a large exchange coupling J ≈ 300 μeV between two (31)P electron spin qubits in silicon. The singlet and triplet states of the coupled spins are monitored in real time by a single-electron transistor, which detects ionization from tunnel-rate-dependent processes in the coupled spin system, yielding single-shot readout fidelities above 95%. The triplet to singlet relaxation time T(1) ≈ 4 ms at zero magnetic field agrees with the theoretical prediction for J-coupled 31P dimers in silicon. The time evolution of the two-electron state populations gives further insight into the valley-orbit eigenstates of the donor dimer, valley selection rules and relaxation rates, and the role of hyperfine interactions. These results pave the way to the realization of two-qubit quantum logic gates with spins in silicon and highlight the necessity to adopt gating schemes compatible with weak J-coupling strengths. PMID:24972221

  14. Non-chromatographic preparation of a bacterially produced single-shot modular virus-like particle capsomere vaccine for avian influenza.

    PubMed

    Wibowo, Nani; Wu, Yang; Fan, Yuanyuan; Meers, Joanne; Lua, Linda H L; Middelberg, Anton P J

    2015-11-01

    Highly pathogenic avian influenza (HPAI) causes significant economic loss, reduced food security and poses an ongoing pandemic threat. Poultry vaccination significantly decreases these problems and recognizes that the health of humans, animals and ecosystems are connected. Low-cost manufacture of poultry vaccine matched quickly to the ever-changing circulating strain is needed for effective vaccination. Here, we re-engineered the process to manufacture bacterially synthesized modular capsomere comprising influenza M2e, previously shown to confer complete protection in challenged mice, for application in poultry. Modular capsomere was prepared using a simplified non-chromatographic salting-out precipitation method and its immunogenicity tested in vivo in poultry. Modular capsomere crudely purified by precipitation (pCapM2e) contained more contaminants than equivalent product purified by chromatography (cCapM2e). Unadjuvanted pCapM2e containing 80 EU of endotoxin per dose was inferior to highly purified and adjuvanted cCapM2e (2 EU per dose). However, addition of adjuvant to pCapM2e resulting in high immunogenicity after only a single dose of vaccination, yet without any local adverse reaction. This finding suggests a strong synergy between adjuvant, antigen and contaminants, and the possible existence of a "Goldilocks" level of contaminants, where high immunogenicity and low reactogenicity can be obtained in a single-shot vaccination. The simplified process offers potential cost and speed advantages to address the needs in influenza poultry vaccination in low-cost veterinary markets.

  15. Reflection, phase and en- face sectional imaging of scattering objects using quasi-single-shot wide-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Anna, Tulsi; Kimura, Satoshi; Mehta, Dalip Singh; Sato, Manabu

    2015-10-01

    We report a quasi-single-shot wide-field optical coherence tomography system that enables to measure the reflection, phase and en- face OCT images from the same setup using the glass jig. The jig consisting of a wedge glass substrate and a glue dot is contacted to the tissue surfaces, and the data within glue dot is used to reduce the phase noise of the interference signal. The reconstructed image size of the object was 4.0 mm × 4.3 mm. The standard deviation (STD) of the phase variation was minimized by 54 % and obtained to be 0.027 rad for the poke tissue. The corresponding STD in optical path length change was measured to be 1.4 nm. The refractive index of the water and poke tissue at the surface is also evaluated as 1.36 and 1.39, respectively, using reflection intensity images. Further, the en- face sectional images of the tissue sample are also measured.

  16. Single-shot gas-phase thermometry using pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering

    NASA Astrophysics Data System (ADS)

    Miller, Joseph D.; Roy, Sukesh; Slipchenko, Mikhail N.; Gord, James R.; Meyer, Terrence R.

    2011-08-01

    High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate single-shot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps to 30 ps. This time delay allows for uncorrected best-fit N2-RCARS temperature measurements with ~1% accuracy. Hence, the hybrid fs/ps RCARS approach can be performed with kHz-rate laser sources while avoiding corrections that can be difficult to predict in unsteady flows.

  17. Single-shot gas-phase thermometry using pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering.

    PubMed

    Miller, Joseph D; Roy, Sukesh; Slipchenko, Mikhail N; Gord, James R; Meyer, Terrence R

    2011-08-01

    High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate single-shot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps to 30 ps. This time delay allows for uncorrected best-fit N2-RCARS temperature measurements with ~1% accuracy. Hence, the hybrid fs/ps RCARS approach can be performed with kHz-rate laser sources while avoiding corrections that can be difficult to predict in unsteady flows.

  18. Measuring single-shot, picosecond optical damage threshold in Ge, Si, and sapphire with a 5.1-μm laser

    DOE PAGES

    Agustsson, R.; Pogorelsky, I.; Arab, E.; Murokh, A.; O"Shea, B.; Ovodenko, A.; Rosenzweig, J.; Solovyov, V.; Tilton, R.

    2015-11-18

    Optical photonic structures driven by picosecond, GW-class lasers are emerging as promising novel sources of electron beams and high quality X-rays. Due to quadratic dependence on wavelength of the laser ponderomotive potential, the performance of such sources scales very favorably towards longer drive laser wavelengths. However, to take full advantage of photonic structures at mid-IR spectral region, it is important to determine optical breakdown limits of common optical materials. To this end, an experimental study was carried out at a wavelength of 5 µm, using a frequency-doubled CO2 laser source, with 5 ps pulse length. Single-shot optical breakdowns were detectedmore » and characterized at different laser intensities, and damage threshold values of 0.2, 0.3, and 7.0 J/cm2, were established for Ge, Si, and sapphire, respectively. As a result, the measured damage threshold values were stable and repeatable within individual data sets, and across varying experimental conditions.« less

  19. A novel technique for single-shot energy-resolved 2D x-ray imaging of plasmas relevant for the inertial confinement fusion

    SciTech Connect

    Labate, L.; Koester, P.; Levato, T.; Gizzi, L. A.

    2012-10-15

    A novel x-ray diagnostic of laser-fusion plasmas is described, allowing 2D monochromatic images of hot, dense plasmas to be obtained in any x-ray photon energy range, over a large domain, on a single-shot basis. The device (named energy-encoded pinhole camera) is based upon the use of an array of many pinholes coupled to a large area CCD camera operating in the single-photon mode. The available x-ray spectral domain is only limited by the quantum efficiency of scientific-grade x-ray CCD cameras, thus extending from a few keV up to a few tens of keV. Spectral 2D images of the emitting plasma can be obtained at any x-ray photon energy provided that a sufficient number of photons had been collected at the desired energy. Results from recent inertial confinement fusion related experiments will be reported in order to detail the new diagnostic.

  20. Measuring single-shot, picosecond optical damage threshold in Ge, Si, and sapphire with a 5.1-μm laser

    SciTech Connect

    Agustsson, R.; Pogorelsky, I.; Arab, E.; Murokh, A.; O"Shea, B.; Ovodenko, A.; Rosenzweig, J.; Solovyov, V.; Tilton, R.

    2015-11-18

    Optical photonic structures driven by picosecond, GW-class lasers are emerging as promising novel sources of electron beams and high quality X-rays. Due to quadratic dependence on wavelength of the laser ponderomotive potential, the performance of such sources scales very favorably towards longer drive laser wavelengths. However, to take full advantage of photonic structures at mid-IR spectral region, it is important to determine optical breakdown limits of common optical materials. To this end, an experimental study was carried out at a wavelength of 5 µm, using a frequency-doubled CO2 laser source, with 5 ps pulse length. Single-shot optical breakdowns were detected and characterized at different laser intensities, and damage threshold values of 0.2, 0.3, and 7.0 J/cm2, were established for Ge, Si, and sapphire, respectively. As a result, the measured damage threshold values were stable and repeatable within individual data sets, and across varying experimental conditions.

  1. Single-shot readout and relaxation of singlet and triplet states in exchange-coupled 31P electron spins in silicon.

    PubMed

    Dehollain, Juan P; Muhonen, Juha T; Tan, Kuan Y; Saraiva, Andre; Jamieson, David N; Dzurak, Andrew S; Morello, Andrea

    2014-06-13

    We present the experimental observation of a large exchange coupling J ≈ 300 μeV between two (31)P electron spin qubits in silicon. The singlet and triplet states of the coupled spins are monitored in real time by a single-electron transistor, which detects ionization from tunnel-rate-dependent processes in the coupled spin system, yielding single-shot readout fidelities above 95%. The triplet to singlet relaxation time T(1) ≈ 4 ms at zero magnetic field agrees with the theoretical prediction for J-coupled 31P dimers in silicon. The time evolution of the two-electron state populations gives further insight into the valley-orbit eigenstates of the donor dimer, valley selection rules and relaxation rates, and the role of hyperfine interactions. These results pave the way to the realization of two-qubit quantum logic gates with spins in silicon and highlight the necessity to adopt gating schemes compatible with weak J-coupling strengths.

  2. Beech T-34C Turbo Mentor

    NASA Technical Reports Server (NTRS)

    1978-01-01

    While most often flown as a photo chase aircraft, the Beech T-34C Turbo Mentor has performed research itself, notably with a laminar flow gloved wing. The aircraft is equipped with a luggage pod under its starboard wing. In 1989, the T-34 was used to sample Space Shuttle exhaust during mission STS-34.

  3. Aerodynamic seal assemblies for turbo-machinery

    SciTech Connect

    Bidkar, Rahul Anil; Wolfe, Christopher; Fang, Biao

    2015-09-29

    The present application provides an aerodynamic seal assembly for use with a turbo-machine. The aerodynamic seal assembly may include a number of springs, a shoe connected to the springs, and a secondary seal positioned about the springs and the shoe.

  4. Hemodynamic evaluation with TURBO BRISK--a rapid phase contrast angiography technique.

    PubMed

    Anayiotos, A S; Kortright, E; Doyle, M; Walsh, E G; Fuisz, A R; Pohost, G M

    2000-01-01

    Hemodynamic imaging by phase contrast angiography was significantly accelerated by selective interpolation and segmentation in k-space using TURBO BRISK. The method was tested in vitro on three independent flowfields, representative of human blood rheology: a straight tube simulating the descending aorta, a curved tube simulating the aortic arch and a two-chamber orifice flow model simulating valvular regurgitation. The results were compared to data obtained by Laser Doppler Velocimetry (LDV) and showed good agreement. For the straight tube, the flow velocity obtained by five TURBO BRISK methods with increasing segmentation factors and corresponding time savings showed good agreement with LDV. For the curved tube, the velocity showed good general agreement with some differences in the decelerating part of the cycle, and in the low-velocity secondary flow structures. The orifice flow evaluation, the most time consuming case, was performed by the control volume method. It showed good agreement with actual flows through the orifice. Data acquisitions for TURBO-4 BRISK could be performed in 20s for each velocity component. The method shows promise for breath-hold acquisitions in clinical applications, including calculation of blood flow volumes through diseased arteries, measurement of blood backflow volumes through dysfunctional heart valves to time valve replacement operations, and evaluation of arterial wall shear stress, an important factor in the genesis of atherosclerosis.

  5. Evaluation of vaccines for H5N1 influenza virus in ferrets reveals the potential for protective single-shot immunization.

    PubMed

    Middleton, Deborah; Rockman, Steven; Pearse, Martin; Barr, Ian; Lowther, Sue; Klippel, Jessica; Ryan, David; Brown, Lorena

    2009-08-01

    As part of influenza pandemic preparedness, policy decisions need to be made about how best to utilize vaccines once they are manufactured. Since H5N1 avian influenza virus has the potential to initiate the next human pandemic, isolates of this subtype have been used for the production and testing of prepandemic vaccines. Clinical trials of such vaccines indicate that two injections of preparations containing adjuvant will be required to induce protective immunity. However, this is a working assumption based on classical serological measures only. Examined here are the dose of viral hemagglutinin (HA) and the number of inoculations required for two different H5N1 vaccines to achieve protection in ferrets after lethal H5N1 challenge. Ferrets inoculated twice with 30 microg of A/Vietnam/1194/2004 HA vaccine with AlPO4, or with doses as low as 3.8 microg of HA with Iscomatrix (ISCOMATRIX, referred to as Iscomatrix herein, is a registered trademark of CSL Limited) adjuvant, were completely protected against death and disease after H5N1 challenge, and the protection lasted at least 15 months. Cross-clade protection was also observed with both vaccines. Significantly, complete protection against death could be achieved with only a single inoculation of H5N1 vaccine containing as little as 15 microg of HA with AlPO4 or 3.8 microg of HA with Iscomatrix adjuvant. Ferrets vaccinated with the single-injection Iscomatrix vaccines showed fewer clinical manifestations of infection than those given AlPO4 vaccines and remained highly active. Our data provide the first indication that in the event of a future influenza pandemic, effective mass vaccination may be achievable with a low-dose "single-shot" vaccine and provide not only increased survival but also significant reduction in disease severity.

  6. Development and demonstration of table-top synchronized fast-scan femtosecond time-resolved spectroscopy system by single-shot scan photo detector array

    NASA Astrophysics Data System (ADS)

    Yabushita, Atsushi; Kao, Chih-Hsien; Lee, Yu-Hsien; Kobayashi, Takayoshi

    2015-07-01

    Ultrafast dynamics is generally studied by pump-probe method with laser pulse, which scans optical delay by motorized stage step by step. Using ultrashort laser pulse shorter than typical molecular vibration periods, the pump-probe measurement can study both of electronic dynamics and vibration dynamics simultaneously. The probe wavelength dependence of the ultrafast electronic and vibration dynamics (UEVD) helps us to distinguish the signal contributions from the dynamics of the electronic ground state and that of the electronic excited states, which elucidates primary reaction mechanism after photoexcitation. Meanwhile, the measurement time of UEVD spectroscopy takes too long time to be used in realistic application. In our previous work, we have developed multi-channel lock-in amplifying (MLA) detectors to study UEVD at all probe wavelengths simultaneously, and synchronized it with laser and fast-scan delay stage to scan the data in five seconds. It enabled us to study UEVD spectroscopy even for photo-fragile materials. However, the home-made MLA detectors required for the measurement is expensive and massive in size and weight, thus not suitable for general researchers in the field of ultrafast time-resolved spectroscopy. In the present work, we have developed a table-top synchronized fast-scan femtosecond time-resolved spectroscopy system using single shot scan line CCD. This system measures time-resolved trace at all probe wavelengths simultaneously in five seconds. The CCD-based fast-scan time-resolved spectroscopy system enables us to study ultrafast dynamics of various materials even biomaterials, which have been thought to be hard or even impossible to be studied in previous methods.

  7. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy.

    PubMed

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-04-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10(13) photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV. PMID:27131669

  8. Nonenhanced peripheral MR-angiography (MRA) at 3 Tesla: evaluation of quiescent-interval single-shot MRA in patients undergoing digital subtraction angiography.

    PubMed

    Wagner, Moritz; Knobloch, Gesine; Gielen, Martin; Lauff, Marie-Teres; Romano, Valentina; Hamm, Bernd; Kröncke, Thomas

    2015-04-01

    Quiescent-interval single-shot MRA (QISS-MRA) is a promising nonenhanced imaging technique for assessment of peripheral arterial disease (PAD). Previous studies at 3 Tesla included only very limited numbers of patients for correlation of QISS-MRA with digital subtraction angiography (DSA) as standard of reference (SOR). The aim of this prospective institutional review board-approved study was to compare QISS-MRA at 3 Tesla with DSA in a larger patient group. Our study included 32 consecutive patients who underwent QISS-MRA, contrast-enhanced MRA (CE-MRA), and DSA. Two readers independently performed a per-segment evaluation of QISS-MRA and CE-MRA for image quality and identification of non-significant stenosis (<50%) versus significant stenosis (50-100%). The final dataset included 1,027 vessel segments. Reader 1 and 2 rated image quality as diagnostic in 96.8 and 98.0% of the vessel segments on QISS-MRA and in 99.3 and 98.4% of the vessel segments on CE-MRA, respectively. DSA was available for 922 segments and detected significant stenosis in 133 segments (14.4%). Consensus reading yielded the following diagnostic parameters for QISS-MRA versus CE-MRA: sensitivity: 83.5% (111/133) versus 82.7% (110/133), p = 0.80; specificity: 93.9% (741/789) versus 95.7% (755/789), p = 0.25; and diagnostic accuracy: 92.4% (852/922) versus 93.8% (865/922), p = 0.35. In conclusion, using DSA as SOR, QISS-MRA and CE-MRA at 3 Tesla showed similar diagnostic accuracy in the assessment of PAD. A limitation of QISS-MRA was the lower rate of assessable vessel segments compared to CE-MRA.

  9. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy.

    PubMed

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-04-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10(13) photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.

  10. Ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using single-shot imaging spectroscopy

    SciTech Connect

    Takeda, Jun Oba, Wataru; Minami, Yasuo; Katayama, Ikufumi; Saiki, Toshiharu

    2014-06-30

    We have observed an irreversible ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using broadband single-shot imaging spectroscopy. The absorbance change that accompanied the ultrafast amorphization was measured via single-shot detection even for laser fluences above the critical value, where a permanent amorphized mark was formed. The observed rise time to reach the amorphization was found to be ∼130–200 fs, which was in good agreement with the half period of the A{sub 1} phonon frequency in the octahedral GeTe{sub 6} structure. This result strongly suggests that the ultrafast amorphization can be attributed to the rearrangement of Ge atoms from an octahedral structure to a tetrahedral structure. Finally, based on the dependence of the absorbance change on the laser fluence, the stability of the photoinduced amorphous phase is discussed.

  11. Turbo codes for deep-space communications

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Pollara, F.

    1995-01-01

    Turbo codes were recently proposed by Berrou, Glavieux, and Thitimajshima, and it has been claimed these codes achieve near-Shannon-limit error correction performance with relatively simple component codes and large interleavers. A required E(b)/N(o) of 0.7 dB was reported for a bit error rate of 10(exp -5), using a rate 1/2 turbo code. However, some important details that are necessary to reproduce these results were omitted. This article confirms the accuracy of these claims, and presents a complete description of an encoder/decoder pair that could be suitable for deep-space applications, where lower rate codes can be used. We describe a new simple method for trellis termination, analyze the effect of interleaver choice on the weight distribution of the code, and introduce the use of unequal rate component codes, which yield better performance.

  12. Turbo Equalization Using Partial Gaussian Approximation

    NASA Astrophysics Data System (ADS)

    Zhang, Chuanzong; Wang, Zhongyong; Manchon, Carles Navarro; Sun, Peng; Guo, Qinghua; Fleury, Bernard Henri

    2016-09-01

    This paper deals with turbo-equalization for coded data transmission over intersymbol interference (ISI) channels. We propose a message-passing algorithm that uses the expectation-propagation rule to convert messages passed from the demodulator-decoder to the equalizer and computes messages returned by the equalizer by using a partial Gaussian approximation (PGA). Results from Monte Carlo simulations show that this approach leads to a significant performance improvement compared to state-of-the-art turbo-equalizers and allows for trading performance with complexity. We exploit the specific structure of the ISI channel model to significantly reduce the complexity of the PGA compared to that considered in the initial paper proposing the method.

  13. Pricing turbo warrants under mixed-exponential jump diffusion model

    NASA Astrophysics Data System (ADS)

    Yu, Jianfeng; Xu, Weidong

    2016-06-01

    Turbo warrant is a special type of barrier options in which the rebate is calculated as another exotic option. In this paper, using Laplace transforms we obtain the valuation of turbo warrant under the mixed-exponential jump diffusion model, which is able to approximate any jump size distribution. The numerical Laplace inversion examples verify that the analytical solutions are accurate. The results of simulation confirm the argument that jump risk should not be ignored in the valuation of turbo warrants.

  14. TurboTech Technical Evaluation Automated System

    NASA Technical Reports Server (NTRS)

    Tiffany, Dorothy J.

    2009-01-01

    TurboTech software is a Web-based process that simplifies and semiautomates technical evaluation of NASA proposals for Contracting Officer's Technical Representatives (COTRs). At the time of this reporting, there have been no set standards or systems for training new COTRs in technical evaluations. This new process provides boilerplate text in response to interview style questions. This text is collected into a Microsoft Word document that can then be further edited to conform to specific cases. By providing technical language and a structured format, TurboTech allows the COTRs to concentrate more on the actual evaluation, and less on deciding what language would be most appropriate. Since the actual word choice is one of the more time-consuming parts of a COTRs job, this process should allow for an increase in quantity of proposals evaluated. TurboTech is applicable to composing technical evaluations of contractor proposals, task and delivery orders, change order modifications, requests for proposals, new work modifications, task assignments, as well as any changes to existing contracts.

  15. Noise suppressor for turbo fan jet engines

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y. (Inventor)

    1983-01-01

    A noise suppressor is disclosed for installation on the discharge or aft end of a turbo fan engine. Within the suppressor are fixed annular airfoils which are positioned to reduce the relative velocity between the high temperature fast moving jet exhaust and the low temperature slow moving air surrounding it. Within the suppressor nacelle is an exhaust jet nozzle which constrains the shape of the jet exhaust to a substantially uniform elongate shape irrespective of the power setting of the engine. Fixed ring airfoils within the suppressor nacelle therefore have the same salutary effects irrespective of the power setting at which the engine is operated.

  16. Turbo-supercharger for internal combustion engine

    SciTech Connect

    Inoue, K.; Suzuki, M.; Narisawa, R.; Terabe, I.; Kubota, O.

    1988-04-05

    A turbo-supercharged motorcycle is described including: a frame; an engine mounted on the frame and having suction pipe defining a suction passage and an exhaust pipe defining an exhaust passage; a turbo-supercharger connected with the engine and comprising; a turbine disposed at an intermediate portion of the exhaust passage for the engine and driven by a gas flowing therein, and a compressor disposed at an intermediate portion of the suction passage for the engine and driven by the turbine; a pre-chamber disposed at the portion of the suction passage which is on the downstream side of the compressor; a branch passage connected to the suction passage at the portion thereof which is upstream of the compressor; a resonance chamber communicated with the suction passage via the branch passage; and a throttle valve disposed in the suction passage downstream of the pre-chamber. The resonance chamber is formed by means for preventing surging positioned at a forward portion of the frame.

  17. Turbo-generator control with variable valve actuation

    SciTech Connect

    Vuk, Carl T.

    2011-02-22

    An internal combustion engine incorporating a turbo-generator and one or more variably activated exhaust valves. The exhaust valves are adapted to variably release exhaust gases from a combustion cylinder during a combustion cycle to an exhaust system. The turbo-generator is adapted to receive exhaust gases from the exhaust system and rotationally harness energy therefrom to produce electrical power. A controller is adapted to command the exhaust valve to variably open in response to a desired output for the turbo-generator.

  18. A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies

    SciTech Connect

    Szlachetko, J.; Nachtegaal, M.; Boni, E. de; Willimann, M.; Safonova, O.; Sa, J.; Smolentsev, G.; Szlachetko, M.; Bergamaschi, A.; Schmitt, B.; David, C.; Luecke, A.; Bokhoven, J. A. van; Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y.; Jagodzinski, P.

    2012-10-15

    We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

  19. A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies.

    PubMed

    Szlachetko, J; Nachtegaal, M; de Boni, E; Willimann, M; Safonova, O; Sa, J; Smolentsev, G; Szlachetko, M; van Bokhoven, J A; Dousse, J-Cl; Hoszowska, J; Kayser, Y; Jagodzinski, P; Bergamaschi, A; Schmitt, B; David, C; Lücke, A

    2012-10-01

    We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

  20. Turbo Pump Fed Micro-Rocket Engine

    NASA Astrophysics Data System (ADS)

    Miotti, P.; Tajmar, M.; Seco, F.; Guraya, C.; Perennes, F.; Soldati, A.; Lang, M.

    2004-10-01

    Micro-satellites (from 10kg up to 100kg) have mass, volume, and electrical power constraints due to their low dimensions. These limitations lead to the lack in currently available active orbit control systems in micro-satellites. Therefore, a micro-propulsion system with a high thrust to mass ratio is required to increase the potential functionality of small satellites. Mechatronic is presently working on a liquid bipropellant micro-rocket engine under contract with ESA (Contract No.16914/NL/Sfe - Micro-turbo-machinery Based Bipropellant System Using MNT). The advances in Mechatronic's project are to realise a micro-rocket engine with propellants pressurised by micro-pumps. The energy for driving the pumps would be extracted from a micro-turbine. Cooling channels around the nozzle would be also used in order to maintain the wall material below its maximum operating temperature. A mass budget comparison with more traditional pressure-fed micro-rockets shows a real benefit from this system in terms of mass reduction. In the paper, an overview of the project status in Mechatronic is presented.

  1. TurboBrayton Cryocooler: A Flight Worthy and Promising Future

    NASA Technical Reports Server (NTRS)

    Gibbon, Judith A.; Swift, Walt L.; Zagarola, Mark V.; DiPirro, Mike; Whitehouse, Paul

    1999-01-01

    A new development in cryocooler technology, a reverse TurboBrayton cycle cryocooler, developed by Creare, Inc. of Hanover, NH, has now been flight tested. This cooler provides high reliability and long life. With no linear moving components common in current flight cryocoolers, the TurboBrayton cooler requires no active control systems to provide a vibration-free signature. The cooler provides first stage cooling for advanced cryogenic systems and serves as a direct replacement for stored cryogen systems with a longer lifetime. Following a successful flight on STS-95, a TurboBrayton cryocooler will be flown on Hubble Space Telescope (HST) in 2000 to provide renewed refrigeration capability for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). The TurboBrayton cycle cooler is a promising technology already being considered for additional flight programs such as Next Generation Space Telescope (NGST) and Constellation X. These future missions require an advanced generation of the cooler that is currently under development to provide cooling at 10K and less. This paper presents an overview of the current generation cooler with recent flight test results and details the current plans and development progress on the next generation TurboBrayton technology for future missions.

  2. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. (a) No person may dispatch or take off a nonturbine or turbo-propeller-powered airplane...

  3. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered airplanes... flight or takeoff a nonturbine or turbo-propeller-powered airplane unless, considering the wind and...

  4. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered airplanes... flight or takeoff a nonturbine or turbo-propeller-powered airplane unless, considering the wind and...

  5. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. (a) No person may dispatch or take off a nonturbine or turbo-propeller-powered airplane...

  6. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. (a) No person may dispatch or take off a nonturbine or turbo-propeller-powered airplane...

  7. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. (a) No person may dispatch or take off a nonturbine or turbo-propeller-powered airplane...

  8. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered airplanes... flight or takeoff a nonturbine or turbo-propeller-powered airplane unless, considering the wind and...

  9. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. (a) No person may dispatch or take off a nonturbine or turbo-propeller-powered airplane...

  10. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered airplanes... flight or takeoff a nonturbine or turbo-propeller-powered airplane unless, considering the wind and...

  11. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Fuel supply: Nonturbine and turbo-propeller... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered airplanes... flight or takeoff a nonturbine or turbo-propeller-powered airplane unless, considering the wind and...

  12. Reduced complexity turbo equalization using a dynamic Bayesian network

    NASA Astrophysics Data System (ADS)

    Myburgh, Hermanus C.; Olivier, Jan C.; van Zyl, Augustinus J.

    2012-12-01

    It is proposed that a dynamic Bayesian network (DBN) is used to perform turbo equalization in a system transmitting information over a Rayleigh fading multipath channel. The DBN turbo equalizer (DBN-TE) is modeled on a single directed acyclic graph by relaxing the Markov assumption and allowing weak connections to past and future states. Its complexity is exponential in encoder constraint length and approximately linear in the channel memory length. Results show that the performance of the DBN-TE closely matches that of a traditional turbo equalizer that uses a maximum a posteriori equalizer and decoder pair. The DBN-TE achieves full convergence and near-optimal performance after small number of iterations.

  13. Bandwidth analysis of all-optical turbo-switch

    NASA Astrophysics Data System (ADS)

    Zhou, Peng; Yang, Xuelin; Hu, Xiaonan; Hu, Weisheng

    2015-01-01

    We propose and develop a frequency-domain model to analyze the bandwidth of all-optical turbo-switch. The model has taken the spatial inhomogeneity of semiconductor optical amplifier (SOA) into consideration for the first time. The simulations based on the model show that the 3-dB bandwidth of turbo-switch could reach up to ~270 GHz when the second SOA is oversaturated. However, the overshoot will be higher, which may result in the distortion of the output signal. There is a trade-off between the bandwidth and the flatness of frequency response characteristics for turbo-switch operation. In addition, the optimum position of the delay-interferometer (DI) is investigated, showing that the level of the overshoot is relatively lower if the DI is placed between the two SOAs.

  14. Transfer function bounds on the performance of turbo codes

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Dolinar, S.; Pollara, F.; Mceliece, R. J.

    1995-01-01

    In this article we apply transfer function bounding techniques to obtain upper bounds on the bit-error rate for maximum likelihood decoding of turbo codes constructed with random permutations. These techniques are applied to two turbo codes with constraint length 3 and later extended to other codes. The performance predicted by these bounds is compared with simulation results. The bounds are useful in estimating the 'error floor' that is difficult to measure by simulation, and they provide insight on how to lower this floor. More refined bounds are needed for accurate performance measures at lower signal-to-noise ratios.

  15. 21. Interior, Turbo Blower Building. Furnaceblowing engines included one Elliot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Interior, Turbo Blower Building. Furnace-blowing engines included one Elliot and two Brown-Boveri steam-drive turbines (shown here). The north end of the building house the plant's machine shop. - Central Furnaces, 2650 Broadway, east bank of Cuyahoga River, Cleveland, Cuyahoga County, OH

  16. Neon turbo-Brayton cycle refrigerator for HTS power machines

    NASA Astrophysics Data System (ADS)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  17. Turtlegraphics: A Comparison of Logo and Turbo Pascal.

    ERIC Educational Resources Information Center

    VanLengen, Craig A.

    1989-01-01

    The integrated compiler of the Turbo Pascal environment allows the execution of a completed program independent of the developed environment and with greater execution speed, in comparison with LOGO. Conversion table of turtle-graphic commands for the two languages is presented. (Author/YP)

  18. Nonlinear bubble nucleation and growth following filament and white-light continuum generation induced by a single-shot femtosecond laser pulse into dielectrics based on consideration of the time scale

    SciTech Connect

    Mizushima, Yuki; Saito, Takayuki

    2015-09-14

    Bubble nucleation and growth following plasma channeling (filament) and white-light continuum in liquid irradiated by a single-shot fs-pulse were experimentally investigated with close observation of the time scale. Making full use of a new confocal system and time-resolved visualization techniques, we obtained evidence suggestive of a major/minor role of the non-linear/thermal effects during the fs-pulse-induced bubble's fountainhead (10{sup −13} s) and growth (10{sup −7} s), which was never observed with the use of the ns-pulse (i.e., optic cavitation). In this context, the fs-pulse-induced bubble is not an ordinary optic cavitation but rather is nonlinear-optic cavitation. We present the intrinsic differences in the dominant-time domain of the fs-pulse and ns-pulse excitation, and intriguingly, a mere hundred femtoseconds' excitation predetermines the size of the bubble appearing several microseconds after irradiation. That is, the nucleation happens temporally beyond a six-order-of-magnitude difference.

  19. Improved time efficiency and accuracy in diffusion tensor microimaging with multiple-echo acquisition

    NASA Astrophysics Data System (ADS)

    Gulani, Vikas; Weber, Thomas; Neuberger, Thomas; Webb, Andrew G.

    2005-12-01

    In high-field NMR microscopy rapid single-shot imaging methods, for example, echo planar imaging, cannot be used for determination of the apparent diffusion tensor (ADT) due to large magnetic susceptibility effects. We propose a pulse sequence in which a diffusion-weighted spin-echo is followed by multiple gradient-echoes with additional diffusion weighting. These additional echoes can be used to calculate the ADT and T2∗ maps. We show here that this results in modest but consistent improvements in the accuracy of ADT determination within a given total data acquisition time. The method is tested on excised, chemically fixed rat spinal cords.

  20. Single-Shot Echo-Planar Diffusion-Weighted MR Imaging at 3T and 1.5T for Differentiation of Benign Vertebral Fracture Edema and Tumor Infiltration

    PubMed Central

    Park, Hee Jin; Rho, Myung Ho; Chung, Eun Chul; Kim, Mi Sung; Kwon, Heon Ju; Youn, In Young

    2016-01-01

    Objective To compare the apparent diffusion coefficient (ADC) value using single-shot echo-planar imaging sequences at 3T and 1.5T for differentiation of benign fracture edema and tumor infiltration of the vertebral body. Materials and Methods A total of 46 spinal examinations were included in the 1.5T MRI group, and a total of 40 spinal examinations were included in the 3T MRI group. The ADC values of the lesion were measured and calculated. The diagnostic performance of the conventional MR image containing sagittal T2-weighted fat saturated image and each diffusion weighted image (DWI) with an ADC value with different b values were evaluated. Results The mean ADC value of the benign lesions was higher than that of the malignant lesions on 1.5T and 3T (p < 0.05). The sensitivity of the diagnostic performance was higher with an additional DWI in both 1.5T and 3T, but the sensitivities were similar with the addition of b values of 400 and 1000. The specificities of the diagnostic performances did not show significant differences (p value > 0.05). The diagnostic accuracies were higher when either of the DWIs (b values of 400 and 1000) was added to routine MR image for 1.5T and 3T. Statistical differences between 1.5T and 3T or between b values of 400 and 1000 were not seen. Conclusion The ADC values of the benign lesions were significantly higher than those of the malignant lesions on 1.5T and 3T. There was no statistically significant difference in the diagnostic performances when either of the DWIs (b values of 400 and 1000) was added to the routine MR image for 1.5T and 3T. PMID:27587948

  1. Performance analysis of optical wireless communication system based on two-fold turbo code

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Huang, Dexiu; Yuan, Xiuhua

    2005-11-01

    Optical wireless communication (OWC) is beginning to emerge in the telecommunications market as a strategy to meet last-mile demand owing to its unique combination of features. Turbo codes have an impressive near Shannon-limit error correcting performance. Twofold turbo codes have been recently introduced as the least complex member of the multifold turbo code family. In this paper, at first, we present the mathematical model of signal and optical wireless channel with fading and bit error rate model with scintillation, then we provide a new turbo code method to use in OWC system, we can obtain a better BER curse of OWC system with twofold turbo code than with common turbo code.

  2. Multiple turbo codes for deep-space communications

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Pollara, F.

    1995-01-01

    In this article, we introduce multiple turbo codes and a suitable decoder structure derived from an approximation to the maximum a posteriori probability (MAP) decision rule, which is substantially different from the decoder for two-code-based encoders. We analyze the effect of interleaver choice on the weight distribution of the code, and we describe simulation results on the improved performance of these new codes.

  3. A Turbo Co/Decoder Implementation for Next Generation DVB-S2

    NASA Astrophysics Data System (ADS)

    Benedetto, S.; Botticchio, T.; Burzigotti, P.; de Gaudenzi, R.; Martiniez, A.; Montorsi, G.; Richichi, F.; Tabacco, P.

    Present work describes the algorithmic design and show the performance of a Turbo Decoder aimed for low Eb/No working points (near Shannon limit) that was purposely design to work in a pragmatic approach with the following constellations QPSK, 8PSK, 16APSK, 16QAM. This Turbo Codec is based on a pure Turbo Codes implementation without the need of additional Reed Solomon Outer Codec.

  4. VLSI design of turbo decoder for integrated communication system on a chip applications

    NASA Technical Reports Server (NTRS)

    Fang, Wai-Chi; Sethuram, Ashwin; Belevi, Kemal

    2003-01-01

    A high-throughput low-power turbo decoder core has been developed for integrated communication system applications such as satellite communications, wireless LAN, digital TV, cable modem, Digital Video Broadcast (DVB), and xDSL systems. The turbo decoder is based on convolutional constituent codes, which outperform all other Forward Error Correction techniques. This turbo decoder core is parameterizable and can be modified easily to fit any size for advanced communication system-on-chip products. The turbo decoder core provides Forward Error Correction of up to 15 Mbits/sec on a 0.13-micron CMOS FPGA prototyping chip at a power of 0.1 watts.

  5. Which is your choice for prolonging the analgesic duration of single-shot interscalene brachial blocks for arthroscopic shoulder surgery? intravenous dexamethasone 5 mg vs. perineural dexamethasone 5 mg randomized, controlled, clinical trial.

    PubMed

    Chun, Eun Hee; Kim, Youn Jin; Woo, Jae Hee

    2016-06-01

    The aim of this study was to compare the effect of intravenous (I.V.) dexamethasone with that of perineural dexamethasone on the prolongation of analgesic duration of single-shot interscalene brachial plexus blocks (SISB) in patients undergoing arthroscopic shoulder surgery. We performed a prospective, randomized, double-blind, placebo-controlled study. Patients undergoing elective arthroscopic shoulder surgery with ultrasound-guided SISB were enrolled and randomized into 2 groups. A total volume of 12 mL of the study drug was prepared with a final concentration of 0.5% ropivacaine. In the I.V. group, patients received SISB using ropivacaine 5 mg mL with normal saline (control) with dexamethasone 5 mg I.V. injection. In the perineural group, patients received SISB using ropivacaine 5 mg mL with dexamethasone 5 mg, with normal saline 1 mL I.V. injection. The primary outcome was the time to the first analgesic request, defined as the time between the end of the operation and the first request of analgesics by the patient. The secondary outcomes included patient satisfaction scores, side effects, and neurological symptoms. Patients were randomly assigned to 1 of the 2 groups using a computer-generated randomization table. An anesthesiologist blinded to the group assignments prepared the solutions for injection. The patients and the investigator participating in the study were also blinded to the group assignments. One hundred patients were randomized. Data were analyzed for 99 patients. One case in the I.V. group was converted to open surgery and was therefore not included in the study. Perineural dexamethasone significantly prolonged analgesic duration (median, standard error: 1080 minutes, 117.5 minutes) compared with I.V. dexamethasone (810 minutes, 48.1 minutes) (P = 0.02). There were no significant differences in side effects, neurological symptoms, or changes in blood glucose values between the 2 groups. Our results show that perineural

  6. Which is your choice for prolonging the analgesic duration of single-shot interscalene brachial blocks for arthroscopic shoulder surgery? intravenous dexamethasone 5 mg vs. perineural dexamethasone 5 mg randomized, controlled, clinical trial

    PubMed Central

    Chun, Eun Hee; Kim, Youn Jin; Woo, Jae Hee

    2016-01-01

    Abstract The aim of this study was to compare the effect of intravenous (I.V.) dexamethasone with that of perineural dexamethasone on the prolongation of analgesic duration of single-shot interscalene brachial plexus blocks (SISB) in patients undergoing arthroscopic shoulder surgery. We performed a prospective, randomized, double-blind, placebo-controlled study. Patients undergoing elective arthroscopic shoulder surgery with ultrasound-guided SISB were enrolled and randomized into 2 groups. A total volume of 12 mL of the study drug was prepared with a final concentration of 0.5% ropivacaine. In the I.V. group, patients received SISB using ropivacaine 5 mg mL−1 with normal saline (control) with dexamethasone 5 mg I.V. injection. In the perineural group, patients received SISB using ropivacaine 5 mg mL−1 with dexamethasone 5 mg, with normal saline 1 mL I.V. injection. The primary outcome was the time to the first analgesic request, defined as the time between the end of the operation and the first request of analgesics by the patient. The secondary outcomes included patient satisfaction scores, side effects, and neurological symptoms. Patients were randomly assigned to 1 of the 2 groups using a computer-generated randomization table. An anesthesiologist blinded to the group assignments prepared the solutions for injection. The patients and the investigator participating in the study were also blinded to the group assignments. One hundred patients were randomized. Data were analyzed for 99 patients. One case in the I.V. group was converted to open surgery and was therefore not included in the study. Perineural dexamethasone significantly prolonged analgesic duration (median, standard error: 1080 minutes, 117.5 minutes) compared with I.V. dexamethasone (810 minutes, 48.1 minutes) (P = 0.02). There were no significant differences in side effects, neurological symptoms, or changes in blood glucose values between the 2 groups. Our results show that

  7. Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition.

    PubMed

    Thomas, Jean-Baptiste; Lapray, Pierre-Jean; Gouton, Pierre; Clerc, Cédric

    2016-01-01

    Multispectral acquisition improves machine vision since it permits capturing more information on object surface properties than color imaging. The concept of spectral filter arrays has been developed recently and allows multispectral single shot acquisition with a compact camera design. Due to filter manufacturing difficulties, there was, up to recently, no system available for a large span of spectrum, i.e., visible and Near Infra-Red acquisition. This article presents the achievement of a prototype of camera that captures seven visible and one near infra-red bands on the same sensor chip. A calibration is proposed to characterize the sensor, and images are captured. Data are provided as supplementary material for further analysis and simulations. This opens a new range of applications in security, robotics, automotive and medical fields. PMID:27367690

  8. Multislice perfusion of the kidneys using parallel imaging: image acquisition and analysis strategies.

    PubMed

    Gardener, Alexander G; Francis, Susan T

    2010-06-01

    Flow-sensitive alternating inversion recovery arterial spin labeling with parallel imaging acquisition is used to acquire single-shot, multislice perfusion maps of the kidney. A considerable problem for arterial spin labeling methods, which are based on sequential subtraction, is the movement of the kidneys due to respiratory motion between acquisitions. The effects of breathing strategy (free, respiratory-triggered and breath hold) are studied and the use of background suppression is investigated. The application of movement correction by image registration is assessed and perfusion rates are measured. Postacquisition image realignment is shown to improve visual quality and subsequent perfusion quantification. Using such correction, data can be collected from free breathing alone, without the need for a good respiratory trace and in the shortest overall acquisition time, advantageous for patient comfort. The addition of background suppression to arterial spin labeling data is shown to reduce the perfusion signal-to-noise ratio and underestimate perfusion.

  9. Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition

    PubMed Central

    Thomas, Jean-Baptiste; Lapray, Pierre-Jean; Gouton, Pierre; Clerc, Cédric

    2016-01-01

    Multispectral acquisition improves machine vision since it permits capturing more information on object surface properties than color imaging. The concept of spectral filter arrays has been developed recently and allows multispectral single shot acquisition with a compact camera design. Due to filter manufacturing difficulties, there was, up to recently, no system available for a large span of spectrum, i.e., visible and Near Infra-Red acquisition. This article presents the achievement of a prototype of camera that captures seven visible and one near infra-red bands on the same sensor chip. A calibration is proposed to characterize the sensor, and images are captured. Data are provided as supplementary material for further analysis and simulations. This opens a new range of applications in security, robotics, automotive and medical fields. PMID:27367690

  10. Performance analysis of turbo decoder on the W-CDMA uplink layer

    NASA Astrophysics Data System (ADS)

    Fang, Xin; Gao, Xiqi; You, XiaoHu

    2001-10-01

    Turbo code is widely noticed as a code that can achieve the performance close to Shannon's limit. Turbo code (k=3) and Convolutional code (k=9) are adopted for channel coding units of WCDMA standard. The Turbo code is expected for the system of high rate data transmission in view of performance and hardware complexity. In this paper, the simulation platform of W-CDMA uplink is developed by the EDA tool-COSSAP. Channel model is M.1225 with 6 fingers model estimated by channel estimator on the Base Station using discontinuous pilot channel with different pilot modes. The BER simulation performance of turbo decoder based on Log-MAP algorithm under frequency selective fading channel is presented in comparison with conventional Viterbi decoder. The simulation results show that in the case of enough accurate estimation of channel parameters, Turbo decoder has better BER performance at high Eb/N0 than conventional Viterbi decoder.

  11. Signal-processing theory for the TurboRogue receiver

    NASA Technical Reports Server (NTRS)

    Thomas, J. B.

    1995-01-01

    Signal-processing theory for the TurboRogue receiver is presented. The signal form is traced from its formation at the GPS satellite, to the receiver antenna, and then through the various stages of the receiver, including extraction of phase and delay. The analysis treats the effects of ionosphere, troposphere, signal quantization, receiver components, and system noise, covering processing in both the 'code mode' when the P code is not encrypted and in the 'P-codeless mode' when the P code is encrypted. As a possible future improvement to the current analog front end, an example of a highly digital front end is analyzed.

  12. Magnevad--the world's smallest magnetic-bearing turbo pump.

    PubMed

    Goldowsky, Michael

    2004-10-01

    The first animal implant of our Magnevad LVAD is scheduled for the fourth quarter of 2003. This is being performed by the George E. Reed Heart Center of Westchester Medical Center and by New York Medical College; both are in Valhalla, NY. This article summarizes 3 years of development of the miniature axial flow LVAD. Our LVAD has new innovations not found in any other turbo pump to minimize thrombus, blood turbulence, flow separation, and the generation of microemboli. The Magnevad is only 25 mL in volume, similar in size to the Micromed & Jarvik 2000 axial flow turbo pumps that have contacting bearings. US Patent 6 527 699 was issued to Gold Medical on March 4, 2003 and World Wide PCT patents are pending. The discussed improvements (patents pending) are designed to minimize flow separation and turbulence, the precursors of microemboli that lodge in end organs. This problem has been largely ignored in the published literature. A new long-term stable miniature ultrasonic position sensor is used for bearing control. It measures the axial position of the rotor to obtain LVAD differential pressure. Differential pressure is used to obtain pulsating flow and automatic physiologic control. The term "fourth generation pump" is being coined for the Magnevad because in addition to being noncontacting, it inherently measures pump differential pressure on which physiologic control can be based.

  13. Advanced Developments for Low Temperature Turbo-Brayton Cryocoolers

    NASA Technical Reports Server (NTRS)

    Nellis, G. F.; McCormick, J. A.; Sixsmith, H.; Zagarola, M. V.; Swift, W. L.; Gibbon, J. A.; Reilly, J. P.; Obenschain, Arthur F. (Technical Monitor)

    2000-01-01

    Turbo-Brayton cryocooler technology that has been space qualified and demonstrated on the NICMOS cryocooler is being adapted for applications with lower cooling loads at lower telqoeratures. The applications include sensor cooling for space platforms and telescopes at temperatures between 4 K and 35 K, where long life and reliable, vibration-free operation are important. This paper presents recent advances in the miniaturization of components that are critical to these systems. Key issues addressed in adapting the NICMOS cryocooler technology to lower temperatures involve reducing parasitic losses when scaling to smaller size machines. Recent advances include the successful design and testing of a small, permanent magnet driven compressor that operates at up to 10,000 rev/sec and the successful demonstration of self acting gas bearings supporting a I mm. diameter shaft. The compressor is important for cryocoolers with input powers between 50 W and 100 W. The miniature shaft and bearing system has applications in compressors and turbines at temperatures from 300 K to 6 K. These two technology milestones are fundamental to achieving exceptional thermodynamic performance from the turboBrayton system in low temperature systems. The paper discusses the development of these components and test results, and presents the implications of their performance on cryocooler systems.

  14. Life and Reliability Characteristics of TurboBrayton Coolers

    NASA Technical Reports Server (NTRS)

    Breedlove, Jeff J.; Zagarola, Mark; Nellis, Greg; Dolan, Frank; Swift, Walt; Gibbon, Judith; Obenschain, Arthur F. (Technical Monitor)

    2000-01-01

    Wear and internal contaminants are two of the primary factors that influence reliable, long-life operation of turbo-Brayton cryocoolers. This paper describes tests that have been conducted and methods that have been developed for turbo-Brayton components and systems to assure reliable operation. The turbomachines used in these coolers employ self-acting gas bearings to support the miniature high-speed shafts, thus providing vibration-free operation. Because the bearings are self-acting, rubbing contact occurs during initial start-up and shutdown of the machines. Bearings and shafts are designed to endure multiple stop/start cycles without producing particles or surface features that would impair the proper operation of the machines. Test results are presented for a variety of turbomachines used in these systems. The tests document extended operating life and start/stop cycling behavior for machines over a range of time and temperature scales. Contaminants such as moisture and other residual gas impurities can be a source of degraded operation if they freeze out in sufficient quantities to block flow passages or if they mechanically affect the operation of the machines. A post-fabrication bakeout procedure has been successfully used to reduce residual internal contamination to acceptable levels in a closed cycle system. The process was developed during space qualification tests on the NICMOS cryocooler. Moisture levels were sampled over a six-month time interval confirming the effectiveness of the technique. A description of the bakeout procedure is presented.

  15. Efficacy of triplet regimen antiemetic therapy for chemotherapy-induced nausea and vomiting (CINV) in bone and soft tissue sarcoma patients receiving highly emetogenic chemotherapy, and an efficacy comparison of single-shot palonosetron and consecutive-day granisetron for CINV in a randomized, single-blinded crossover study.

    PubMed

    Kimura, Hiroaki; Yamamoto, Norio; Shirai, Toshiharu; Nishida, Hideji; Hayashi, Katsuhiro; Tanzawa, Yoshikazu; Takeuchi, Akihiko; Igarashi, Kentaro; Inatani, Hiroyuki; Shimozaki, Shingo; Kato, Takashi; Aoki, Yu; Higuchi, Takashi; Tsuchiya, Hiroyuki

    2015-03-01

    The first aim of this study was to evaluate combination antiemetic therapy consisting of 5-HT3 receptor antagonists, neurokinin-1 receptor antagonists (NK-1RAs), and dexamethasone for multiple high emetogenic risk (HER) anticancer agents in bone and soft tissue sarcoma. The second aim was to compare the effectiveness of single-shot palonosetron and consecutive-day granisetron in a randomized, single-blinded crossover study. A single randomization method was used to assign eligible patients to the palonosetron or granisetron arm. Patients in the palonosetron arm received a palonosetron regimen during the first and third chemotherapy courses and a granisetron regimen during the second and fourth courses. All patients received NK-1RA and dexamethasone. Patients receiving the palonosetron regimen were administered 0.75 mg palonosetron on day 1, and patients receiving the granisetron regimen were administered 3 mg granisetron twice daily on days 1 through 5. All 24 patients in this study received at least 4 chemotherapy courses. A total of 96 courses of antiemetic therapy were evaluated. Overall, the complete response CR rate (no emetic episodes and no rescue medication use) was 34%, while the total control rate (a CR plus no nausea) was 7%. No significant differences were observed between single-shot palonosetron and consecutive-day granisetron. Antiemetic therapy with a 3-drug combination was not sufficient to control chemotherapy-induced nausea and vomiting (CINV) during chemotherapy with multiple HER agents for bone and soft tissue sarcoma. This study also demonstrated that consecutive-day granisetron was not inferior to single-shot palonosetron for treating CINV.

  16. RARE/Turbo Spin Echo Imaging with Simultaneous MultiSlice Wave-CAIPI

    PubMed Central

    Eichner, Cornelius; Bhat, Himanshu; Grant, P. Ellen; Wald, Lawrence L.; Setsompop, Kawin

    2014-01-01

    Purpose To enable highly accelerated RARE/Turbo Spin Echo (TSE) imaging using Simultaneous MultiSlice (SMS) Wave-CAIPI acquisition with reduced g-factor penalty. Methods SMS Wave-CAIPI incurs slice shifts across simultaneously excited slices while playing sinusoidal gradient waveforms during the readout of each encoding line. This results in an efficient k-space coverage that spreads aliasing in all three dimensions to fully harness the encoding power of coil sensitivities. The novel MultiPINS radiofrequency (RF) pulses dramatically reduce the power deposition of multiband (MB) refocusing pulse, thus allowing high MB factors within the Specific Absorption Rate (SAR) limit. Results Wave-CAIPI acquisition with MultiPINS permits whole brain coverage with 1 mm isotropic resolution in 70 seconds at effective MB factor 13, with maximum and average g-factor penalties of gmax=1.34 and gavg=1.12, and without √R penalty. With blipped-CAIPI, the g-factor performance was degraded to gmax=3.24 and gavg=1.42; a 2.4-fold increase in gmax relative to Wave-CAIPI. At this MB factor, the SAR of the MultiBand and PINS pulses are 4.2 and 1.9 times that of the MultiPINS pulse, while the peak RF power are 19.4 and 3.9 times higher. Conclusion Combination of the two technologies, Wave-CAIPI and MultiPINS pulse, enables highly accelerated RARE/TSE imaging with low SNR penalty at reduced SAR. PMID:25640187

  17. Application of TURBO-AE to Flutter Prediction: Aeroelastic Code Development

    NASA Technical Reports Server (NTRS)

    Hoyniak, Daniel; Simons, Todd A.; Stefko, George (Technical Monitor)

    2001-01-01

    The TURBO-AE program has been evaluated by comparing the obtained results to cascade rig data and to prediction made from various in-house programs. A high-speed fan cascade, a turbine cascade, a turbine cascade and a fan geometry that shower flutter in torsion mode were analyzed. The steady predictions for the high-speed fan cascade showed the TURBO-AE predictions to match in-house codes. However, the predictions did not match the measured blade surface data. Other researchers also reported similar disagreement with these data set. Unsteady runs for the fan configuration were not successful using TURBO-AE .

  18. Study on Performance and Internal Flow Condition of Mini Turbo-Pump

    NASA Astrophysics Data System (ADS)

    Shigemitsu, Toru; Fukutomi, Junichiro; Nasada, Ryoichi

    2010-06-01

    Mini turbo-pumps which have a diameter smaller than 100mm are utilized in many fields; automobile radiator pump, artificial heart pump, cooling pump for electric devices, washing machine pump and so on. And the needs for the mini turbo-pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini turbo-pump design is as simple as possible due to the limitation of the precision for manufacture. But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps because of the low Reynolds number and the size effects. Therefore, we started the research of the mini turbo-pump for the purpose of development of high performance mini turbo-pump with simple structure. As a first step of this research, mini turbo-pump with the 46mm rotor diameter was designed based on the conventional design method in order to clarify the problems for the application of conventional method for mini turbo-pump in details. The three dimensional steady numerical flow analysis was conducted with the commercial code (Fluent6.3). The numerical flow analysis was also performed under the condition with and without a tip clearance because the tip clearance influence on the performance and internal flow condition is extremely large for mini turbo-pumps. It was clarified from the numerical results that head of the mini turbo-pump at the designed point without the tip clearance satisfied the designed value head H = 1.2m and the efficiency is about η = 60% which is acceptable value for the centrifugal pump. On the other hand, head and efficiency decreased drastically with the increase of the tip clearance. The flow condition near the tip region was influenced by the leakage flow from the blade tip. And it is observed by the results of the total pressure distributions that the total

  19. Design modification in rotor blade of turbo molecular pump

    NASA Astrophysics Data System (ADS)

    Iqbal, Munawar; Wasy, Abdul; Batani, Dimitri; Rashid, Haris; Lodhi, M. A. K.

    2012-06-01

    Performance of a Turbo Molecular Pump (TMP) is strongly related to the frequency of the rotor. As rpm increases deflection in the rotor blades starts to occur. Therefore, quality of material and blade design has been modified in order to obtain stable performance at higher speed. To reduce the deformation, stiffer material and change in blade design have been calculated. Significant improvement has been achieved in modeling the blade design using CATIA software. The analysis has been performed by ANSYS workbench. It is shown that the modification in the blade design of TMP rotor has reduced the structural deformation up to 66 percent of the deformation produced in the original blade design under the same conditions. Modified design achieved additional 23 percent rpm which increased TMP's efficiency.

  20. Coupled Receiver/Decoders for Low-Rate Turbo Codes

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon; Divsalar, Dariush

    2005-01-01

    been proposed for receiving weak single- channel phase-modulated radio signals bearing low-rate-turbo-coded binary data. Originally intended for use in receiving telemetry signals from distant spacecraft, the proposed receiver/ decoders may also provide enhanced reception in mobile radiotelephone systems. A radio signal of the type to which the proposal applies comprises a residual carrier signal and a phase-modulated data signal. The residual carrier signal is needed as a phase reference for demodulation as a prerequisite to decoding. Low-rate turbo codes afford high coding gains and thereby enable the extraction of data from arriving radio signals that might otherwise be too weak. In the case of a conventional receiver, if the signal-to-noise ratio (specifically, the symbol energy to one-sided noise power spectral density) of the arriving signal is below approximately 0 dB, then there may not be enough energy per symbol to enable the receiver to recover properly the carrier phase. One could solve the problem at the transmitter by diverting some power from the data signal to the residual carrier. A better solution . a coupled receiver/decoder according to the proposal . could reduce the needed amount of residual carrier power. In all that follows, it is to be understood that all processing would be digital and the incoming signals to be processed would be, more precisely, outputs of analog-to-digital converters that preprocess the residual carrier and data signals at a rate of multiple samples per symbol. The upper part of the figure depicts a conventional receiving system, in which the receiver and decoder are uncoupled, and which is also called a non-data-aided system because output data from the decoder are not used in the receiver to aid in recovering the carrier phase. The receiver tracks the carrier phase from the residual carrier signal and uses the carrier phase to wipe phase noise off the data signal. The receiver typically includes a phase-locked loop

  1. Developments in TurboBrayton Technology for Low Temperature Applications

    NASA Technical Reports Server (NTRS)

    Swift, W. L.; Zagarola, M. V.; Nellis, G. F.; McCormick, J. A.; Gibbon, Judy

    1999-01-01

    A single stage reverse Brayton cryocooler using miniature high-speed turbomachines recently completed a successful space shuttle test flight demonstrating its capabilities for use in cooling the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The NICMOS CryoCooler (NCC) is designed for a cooling load of about 8 W at 65 K, and comprises a closed loop cryocooler coupled to an independent cryogenic circulating loop. Future space applications involve instruments that will require 5 mW to 200 mW of cooling at temperatures between 4 K and 10 K. This paper discusses the extension of Turbo-Brayton technology to meet these requirements.

  2. Assessment of Donlee 3000-horsepower TurboFireXL boiler. Technology Installation Review

    SciTech Connect

    2000-05-01

    This 'Technology Installation Review' (TIR) describes the TurboFireXL industrial boiler technology and presents information on existing applications, energy-saving mechanisms, installation requirements, and relevant case studies.

  3. Deep Space Network turbo decoder infusion: enhanced performance and lower decoder complexity

    NASA Technical Reports Server (NTRS)

    Pollara, F.; Andrews, K.

    2002-01-01

    This article describes the effort to deploy turbo decoders in the Deep Space Network to service missions launching in 2003 and later, and the implications of these new capabilities for the design of future missions.

  4. High-performance VLSI architectures for turbo decoders with QPP interleaver

    NASA Astrophysics Data System (ADS)

    Verma, Shivani; Kumar, S.

    2015-04-01

    This paper analyses different VLSI architectures for 3GPP LTE/LTE-advanced turbo decoders for trade-offs in terms of throughput and area requirement. Data flow graphs for standard SISO MAP (maximum a posteriori) turbo decoder, SW - SISO MAP turbo decoder, PW SISO MAP turbo decoder have been presented, thus analysing their performance. Two variants of quadratic permutation polynomial (QPP) interleaver have been proposed which tend to simplify the complexity of 'mod' operator implementation and provide best compromise between area, delay and power dissipation. Implementation of decoder using one variant of QPP interleaver has also been discussed. A novel approach for area optimisation has been proposed to reduce required number of interleavers for parallel window turbo decoder. Multi-port memory has also been used for parallel turbo decoder. To increase the throughput without any effective increase in area complexity, circuit-level pipelining and retiming have been used. Proposed architectures have been synthesised using Synopsys Design Compiler using 45-nm CMOS technology.

  5. Weight distributions for turbo codes using random and nonrandom permutations

    NASA Technical Reports Server (NTRS)

    Dolinar, S.; Divsalar, D.

    1995-01-01

    This article takes a preliminary look at the weight distributions achievable for turbo codes using random, nonrandom, and semirandom permutations. Due to the recursiveness of the encoders, it is important to distinguish between self-terminating and non-self-terminating input sequences. The non-self-terminating sequences have little effect on decoder performance, because they accumulate high encoded weight until they are artificially terminated at the end of the block. From probabilistic arguments based on selecting the permutations randomly, it is concluded that the self-terminating weight-2 data sequences are the most important consideration in the design of constituent codes; higher-weight self-terminating sequences have successively decreasing importance. Also, increasing the number of codes and, correspondingly, the number of permutations makes it more and more likely that the bad input sequences will be broken up by one or more of the permuters. It is possible to design nonrandom permutations that ensure that the minimum distance due to weight-2 input sequences grows roughly as the square root of (2N), where N is the block length. However, these nonrandom permutations amplify the bad effects of higher-weight inputs, and as a result they are inferior in performance to randomly selected permutations. But there are 'semirandom' permutations that perform nearly as well as the designed nonrandom permutations with respect to weight-2 input sequences and are not as susceptible to being foiled by higher-weight inputs.

  6. Compact and High Thrust Air Turbo Ram Engine

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Kitahara, Kazuki; Inukai, Yasuo

    The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.

  7. An Advanced Turbo-Brayton Converter for Radioisotope Power Systems

    NASA Astrophysics Data System (ADS)

    Zagarola, Mark V.; Izenson, Michael G.; Breedlove, Jeffrey J.; O'Connor, George M.; Ketchum, Andrew C.; Jetley, Richard L.; Simons, James K.

    2005-02-01

    Past work has shown that Brayton power converters are an attractive option for high power, long-duration space missions. More recently, Creare has shown that Brayton technology could be scaled with high efficiency and specific power to lower power levels suitable for radioisotope power conversion systems. Creare is currently leading the development of an advanced turbo-Brayton converter under NASA's Prometheus Program. The converter design is based on space-proven cryocooler technologies that have been shown to be safe; to provide long, maintenance-free lifetimes; and to have high reliability, negligible vibration emittance, and low EMI/EMC. The predicted performance of a converter at the beginning of life is greater than 20% (including electronic inefficiencies and overhead) with a converter specific power of greater than 8 We/kg for a test unit and greater than 15 We/kg for a flight unit. The degradation in performance over a 14-year mission lifetime is predicted to be negligible, and the primary life limiting factor is not expected to be an issue for greater than twice the mission duration. Work during the last year focused on the material and fabrication issues associated with a high temperature turbine and a lightweight recuperator, and the performance issues associated with the high-temperature insulation and power conversion electronics. The development of the converter is on schedule. Thermal vacuum testing to demonstrate a technology readiness level of 5 is currently planned for 2006.

  8. Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner

    SciTech Connect

    Cho, Soo-Yong; Cho, Chong-Hyun; Kim, Chaesil

    2008-09-15

    An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is HFC134a and the maximum cooling capacity of experiment apparatus is 32.7 kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio. (author)

  9. 14 CFR 121.645 - Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... airplanes, other than turbo propeller: Flag and supplemental operations. 121.645 Section 121.645 Aeronautics... airplanes, other than turbo propeller: Flag and supplemental operations. (a) Any flag operation within the...-propeller powered airplane) unless, considering wind and other weather conditions expected, it has...

  10. 14 CFR 121.645 - Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... airplanes, other than turbo propeller: Flag and supplemental operations. 121.645 Section 121.645 Aeronautics... airplanes, other than turbo propeller: Flag and supplemental operations. (a) Any flag operation within the...-propeller powered airplane) unless, considering wind and other weather conditions expected, it has...

  11. 14 CFR 121.645 - Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... airplanes, other than turbo propeller: Flag and supplemental operations. 121.645 Section 121.645 Aeronautics... airplanes, other than turbo propeller: Flag and supplemental operations. (a) Any flag operation within the...-propeller powered airplane) unless, considering wind and other weather conditions expected, it has...

  12. 14 CFR 121.645 - Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... airplanes, other than turbo propeller: Flag and supplemental operations. 121.645 Section 121.645 Aeronautics... airplanes, other than turbo propeller: Flag and supplemental operations. (a) Any flag operation within the...-propeller powered airplane) unless, considering wind and other weather conditions expected, it has...

  13. 14 CFR 121.645 - Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... airplanes, other than turbo propeller: Flag and supplemental operations. 121.645 Section 121.645 Aeronautics... airplanes, other than turbo propeller: Flag and supplemental operations. (a) Any flag operation within the...-propeller powered airplane) unless, considering wind and other weather conditions expected, it has...

  14. PURR-TURBO: a novel pulse sequence for longitudinal relaxographic imaging.

    PubMed

    Lee, J H

    2000-05-01

    A novel pulse sequence based on a segmented phase-encoding scheme for measuring the longitudinal relaxation time (T(1)) value of an NMR signal in an imaging context is introduced. This pulse sequence is a hybrid version of the "single-shot" and "one-shot" inversion recovery (IR) snapshot-FLASH methods. These are also known as "multipoint" IR techniques. The new sequence presented here collects multiple k-space rows at each time point during magnetization recovery, rather than the entire dataset (as in a "single-shot" method) or just one row (as in a "one-shot" method). Thus, it reduces the scanning time without significant sacrifice of the small sampling time advantage of the one-shot IR snapshot-FLASH methods. Furthermore, this approach does not require a high-performance gradient system. Here, we demonstrate that a single slice human brain (1)H(2)O T(1) map with a nominal in-plane resolution of less than (1 mm)2can be obtained at 4 T in about 4 min. Published 2000 Wiley-Liss, Inc.

  15. Turbo-supercharger for an internal combustion engine

    SciTech Connect

    Tadokoro, T.; Matsuda, I.

    1988-03-15

    A turbo-supercharged for an engine is described comprising a supercharging compressor located in an intake system of the engine and an exhaust gas turbine located in an exhaust system of the engine for driving the compressor. The turbine includes a turbine casing and a turbine rotor rotatably supported in the turbine casing. The exhaust system of the engine has exhaust pipe means defining an exhaust passage and connected with the turbine casing. The turbine casing has exhaust gas inlet passage means for directing exhaust gas of the engine from the exhaust passage to the turbine rotor. The inlet passage means include at least a first inlet passage and a second inlet passage which are located in a side-by-side relationship with each other, valve means for closing the second inlet passage, characterized by the fact that the first and second inlet passages are opened to the exhaust passage in the exhaust pipe means respectively through first and second inlet ports which are oriented in a direction opposing exhaust gas flow in the exhaust passage. The exhaust pipe means are formed in a portion adjacent to the turbine casing with a sidewardly bulged portion. The valve means includes a valve member adapted for seating on a valve seat formed in a peripheral portion of the second inlet port for closing the second inlet port and swingable arm means for supporting the valve member swingably on the exhaust pipe means so that the valve member can be moved from a closed position seating on the valve seat against the exhaust gas flow to an open position in which the valve member is located substantially in the bulged portion.

  16. 100,000 hour design life of turbo compressor packages

    SciTech Connect

    1998-05-20

    Many turbomachinery manufacturers and operators typically quote 100,000 hours as a design limit for service life of turbo compressor components. The Pipeline Research Committee initiated this study to review the life limiting criteria for certain critical components and determine if the design target of 100,000 hours can be safely and reliably met or extended with special component management practices. The first phase of the project was to select the turbomachinery components that would be included in the review. Committee members were surveyed with a detailed questionnaire designed to identify critical components based on: high hours (e.g. at or approaching 100,000 hours) the most common engine types operated by the member organizations, and the components of greatest concern from a risk and expense point of view. The selection made covers a wide range of engine types that are of interest to most of the committee companies. This selection represents some 78% of the high hour units operated by the committee and includes components from GE Frame 3 and Frame 5, Solar Saturn, Rolls Royce Avon, and Cooper RT56 engines. The report goes into detail regarding the various damage mechanism which can be the main life limiting factor of the component; creep, fatigue, environmental attack, wear and microstructure instability. For each of the component types selected, the study identifies the life limiting criteria and outlines how the components may be managed for extended life. Many of the selected components can be reliably operated beyond 100,000 hours by following the management practices set out in the report.

  17. The TurboLAN project. Phase 1: Protocol choices for high speed local area networks. Phase 2: TurboLAN Intelligent Network Adapter Card, (TINAC) architecture

    NASA Technical Reports Server (NTRS)

    Alkhatib, Hasan S.

    1991-01-01

    The hardware and the software architecture of the TurboLAN Intelligent Network Adapter Card (TINAC) are described. A high level as well as detailed treatment of the workings of various components of the TINAC are presented. The TINAC is divided into the following four major functional units: (1) the network access unit (NAU); (2) the buffer management unit; (3) the host interface unit; and (4) the node processor unit.

  18. Fault diagnostics for turbo-shaft engine sensors based on a simplified on-board model.

    PubMed

    Lu, Feng; Huang, Jinquan; Xing, Yaodong

    2012-01-01

    Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can't be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD) logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient. PMID:23112645

  19. Turbo codes-based image transmission for channels with multiple types of distortion.

    PubMed

    Yao, Lei; Cao, Lei

    2008-11-01

    Product codes are generally used for progressive image transmission when random errors and packet loss (or burst errors) co-exist. However, the optimal rate allocation considering both component codes gives rise to high-optimization complexity. In addition, the decoding performance may be degraded quickly when the channel varies beyond the design point. In this paper, we propose a new unequal error protection (UEP) scheme for progressive image transmission by using rate-compatible punctured Turbo codes (RCPT) and cyclic redundancy check (CRC) codes only. By sophisticatedly interleaving each coded frame, the packet loss can be converted into randomly punctured bits in a Turbo code. Therefore, error control in noisy channels with different types of errors is equivalent to dealing with random bit errors only, with reduced turbo code rates. A genetic algorithm-based method is presented to further reduce the optimization complexity. This proposed method not only gives a better performance than product codes in given channel conditions but is also more robust to the channel variation. Finally, to break down the error floor of turbo decoding, we further extend the above RCPT/CRC protection to a product code scheme by adding a Reed-Solomon (RS) code across the frames. The associated rate allocation is discussed and further improvement is demonstrated.

  20. Fault Diagnostics for Turbo-Shaft Engine Sensors Based on a Simplified On-Board Model

    PubMed Central

    Lu, Feng; Huang, Jinquan; Xing, Yaodong

    2012-01-01

    Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can't be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD) logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient. PMID:23112645

  1. Fault diagnostics for turbo-shaft engine sensors based on a simplified on-board model.

    PubMed

    Lu, Feng; Huang, Jinquan; Xing, Yaodong

    2012-01-01

    Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can't be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD) logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient.

  2. Whole-body turbo STIR MR imaging: controversies and avenues for development.

    PubMed

    Kavanagh, Eoin; Smith, Clare; Eustace, Stephen

    2003-09-01

    The idea of a non-ionizing high-resolution technique to screen the entire body for occult disease is immensely appealing. This article outlines an evolving technique, controversies and clinical application of whole-body scanning using MRI with turbo short tau inversion recovery tissue excitation.

  3. Investigation of Different Constituent Encoders in a Turbo-code Scheme for Reduced Decoder Complexity

    NASA Technical Reports Server (NTRS)

    Kwatra, S. C.

    1998-01-01

    A large number of papers have been published attempting to give some analytical basis for the performance of Turbo-codes. It has been shown that performance improves with increased interleaver length. Also procedures have been given to pick the best constituent recursive systematic convolutional codes (RSCC's). However testing by computer simulation is still required to verify these results. This thesis begins by describing the encoding and decoding schemes used. Next simulation results on several memory 4 RSCC's are shown. It is found that the best BER performance at low E(sub b)/N(sub o) is not given by the RSCC's that were found using the analytic techniques given so far. Next the results are given from simulations using a smaller memory RSCC for one of the constituent encoders. Significant reduction in decoding complexity is obtained with minimal loss in performance. Simulation results are then given for a rate 1/3 Turbo-code with the result that this code performed as well as a rate 1/2 Turbo-code as measured by the distance from their respective Shannon limits. Finally the results of simulations where an inaccurate noise variance measurement was used are given. From this it was observed that Turbo-decoding is fairly stable with regard to noise variance measurement.

  4. Isothermal thermogravimetric data acquisition analysis system

    NASA Technical Reports Server (NTRS)

    Cooper, Kenneth, Jr.

    1991-01-01

    The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

  5. Acquisition strategies

    SciTech Connect

    Zimmer, M.J.; Lynch, P.W. )

    1993-11-01

    Acquiring projects takes careful planning, research and consideration. Picking the right opportunities and avoiding the pitfalls will lead to a more valuable portfolio. This article describes the steps to take in evaluating an acquisition and what items need to be considered in an evaluation.

  6. Pico-coulomb charge measured at BELLA to percent-level precision using a Turbo-ICT

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Mittelberger, D. E.; Gonsalves, A. J.; Daniels, J.; Mao, H.-S.; Stulle, F.; Bergoz, J.; Leemans, W. P.

    2016-03-01

    Precise diagnostics of picocoulomb level particle bunches produced by laser plasma accelerators (LPAs) can be a significant challenge. Without proper care, the small signals associated with such bunches can be dominated by a background generated by laser, target, laser-plasma interaction and particle induced radiation. In this paper, we report on first charge measurements using the newly developed Turbo-ICT for LPAs. We outline the Turbo-ICT working principle, which allows precise sub-picocoulomb measurements even in the presence of significant background signals. A comparison of the Turbo-ICT, a conventional integrating current transformer (ICT) and a scintillating screen (Lanex) was carried out at the Berkeley Lab Laser Accelerator. Results show that the Turbo-ICT can measure sub-picocoulomb charge accurately and has significantly improved noise immunity compared to the ICT.

  7. An evaluation of Turbo Prolog with an emphasis on its application to the development of expert systems

    NASA Technical Reports Server (NTRS)

    Loftin, Richard B.

    1987-01-01

    Turbo Prolog is a recently available, compiled version of the programming language Prolog. Turbo Prolog is designed to provide not only a Prolog compiler, but also a program development environment for the IBM Personal Computer family. An evaluation of Turbo Prolog was made, comparing its features to other versions of Prolog and to the community of languages commonly used in artificial intelligence (AI) research and development. Three programs were employed to determine the execution speed of Turbo Prolog applied to various problems. The results of this evaluation demonstrated that Turbo Prolog can perform much better than many commonly employed AI languages for numerically intensive problems and can equal the speed of development languages such as OPS5+ and CLIPS, running on the IBM PC. Applications for which Turbo Prolog is best suited include those which (1) lend themselves naturally to backward-chaining approaches, (2) require extensive use of mathematics, (3) contain few rules, (4) seek to make use of the window/color graphics capabilities of the IBM PC, and (5) require linkage to programs in other languages to form a complete executable image.

  8. Joint robustness security in optical OFDM access system with Turbo-coded subcarrier rotation.

    PubMed

    Zhang, Lijia; Liu, Bo; Xin, Xiangjun; Wang, Yongjun

    2015-01-12

    This paper proposes a novel robust physical secure method for optical orthogonal frequency division multiplexing (OFDM) access system based on Turbo-coded subcarrier rotation. It can realize a secure communication while keep robustness to channel noise. The subcarrier rotation is controlled by the interleaver module of Turbo coding, which is under the charge of Logistic map. The random puncturing can further enhance the security. The channel feedback can ensure the puncturing module working at a suitable coding rate. A 72.28 Gb/s encrypted 16QAM-OFDM signal is successfully demonstrated in the experiment. The results show robust performance under different channel noise conditions and good resistance to illegal optical network unit (ONU).

  9. A New Turbo-shaft Engine Control Law during Variable Rotor Speed Transient Process

    NASA Astrophysics Data System (ADS)

    Hua, Wei; Miao, Lizhen; Zhang, Haibo; Huang, Jinquan

    2015-12-01

    A closed-loop control law employing compressor guided vanes is firstly investigated to solve unacceptable fuel flow dynamic change in single fuel control for turbo-shaft engine here, especially for rotorcraft in variable rotor speed process. Based on an Augmented Linear Quadratic Regulator (ALQR) algorithm, a dual-input, single-output robust control scheme is proposed for a turbo-shaft engine, involving not only the closed loop adjustment of fuel flow but also that of compressor guided vanes. Furthermore, compared to single fuel control, some digital simulation cases using this new scheme about variable rotor speed have been implemented on the basis of an integrated system of helicopter and engine model. The results depict that the command tracking performance to the free turbine rotor speed can be asymptotically realized. Moreover, the fuel flow transient process has been significantly improved, and the fuel consumption has been dramatically cut down by more than 2% while keeping the helicopter level fight unchanged.

  10. Dynamic angle stability of an industrial turbo generator connected in power system

    NASA Astrophysics Data System (ADS)

    Grouni, S.; Hallak, M.; Aibeche, A.; Ramdani, A.; Bouallegue, K.

    2014-12-01

    This paper deals with the dynamic problem of oscillation and damping on an industrial turbo generator connected to infinite networks. A set of equations that governs the turbo generator connected to infinite bus are written in characteristic form. The power system stabilizer PSS applied in order to solve the problem of damping internal angle and operating power system synchronization. The PSS model described is inspired from Heffron-Philips model is applied on real parameters simulation under Matlab simulink. The results obtained from practical application are advantageous which variations of amplitude and time mitigation oscillations magnitude of electrical and mechanical output variables. This numerical experiment permits to gain more simplicity compared with several methods applied in a real operating prototyping systems. The PSS that is used will improve the dynamic stability.

  11. [Artificial heart--turbo type blood pump for long-term use].

    PubMed

    Akamatsu, Teruaki

    2003-05-01

    Shortage of donor heart for transplantation necessitates long-term artificial assist heart. Turbo-pump is smaller, simpler and cheaper than the pulsatile displacement type pump, but the turbo-pump has defect of thrombus formation at the shaft seal. Our centrifugal pump with magnetically suspended impellers overcomes this defect and is ready for clinical trials now. The structures and functions are described and are compared with the other newly-developed pump of the same kinds with us. And also the pumps of centrifugal type and axial-type, of which impellers are supported by pivots, are reviewed briefly from the stand point for long-term use. Other pumps are referred too: pumps with hydrodynamic bearing and a pump with the shaft seal which is washed and cooled by saline solution.

  12. Structural design and analysis of a Mach zero to five turbo-ramjet system

    NASA Technical Reports Server (NTRS)

    Spoth, Kevin A.; Moses, Paul L.

    1993-01-01

    The paper discusses the structural design and analysis of a Mach zero to five turbo-ramjet propulsion system for a Mach five waverider-derived cruise vehicle. The level of analysis detail necessary for a credible conceptual design is shown. The results of a finite-element failure mode sizing analysis for the engine primary structure is presented. The importance of engine/airframe integration is also discussed.

  13. DESIGN & DEVELOPMENT OF E-TURBO FOR SUV AND LIGHT TRUCK APPLICATIONS

    SciTech Connect

    Balis, C; Middlemass, C; Shahed, SM

    2003-08-24

    The purpose of the project is to develop an electronically controlled, electrically assisted turbocharging system, e-Turbo, for application to SUV and light truck class of passenger vehicles. Earlier simulation work had shown the benefits of e-Turbo system on increasing low-end torque and improving fuel economy. This paper will present further data from the literature to show that advanced turbocharging can enable diesel engine downsizing of 10-30% with 6-17% improvement in fuel economy. This is in addition to the fuel economy benefit that a turbocharged diesel engine offers over conventional gasoline engines. E-Turbo is necessary to get acceptable driving characteristics with downsized diesel engines. As a first step towards the development of this technology for SUV/light truck sized diesel engines (4-6 litre displacement), design concepts and hardware were evaluated for a smaller engine (2 litre displacement). It was felt that design and developments issues could be minimized, the concept proven progressively on the bench, on a small engine and then applied to a large Vee engine (one on each bank). After successful demonstration of the concept, large turbomachinery could be designed and built specifically for larger SUV sized diesel engines. This paper presents the results of development of e-Turbo for a 2 litre diesel engine. A detailed comparison of several electric assist technologies including permanent magnet, six-phase induction and conventional induction motor/generator technology was done. A comparison of switched reluctance motor technology was also done although detailed design was not carried out.

  14. Investigations on the sensitivity of the computer code TURBO-2D

    NASA Astrophysics Data System (ADS)

    Amon, B.

    1994-12-01

    The two-dimensional computer model TURBO-2D for the calculation of two-phase flow was used to calculate the cold injection of fuel into a model chamber. Investigations of the influence of the input parameter on its sensitivity relative to the obtained results were made. In addition to that calculations were performed and compared using experimental injection pressure data and corresponding averaged injection parameter.

  15. Single-shot simulations of dynamics of quantum dark solitons

    NASA Astrophysics Data System (ADS)

    Syrwid, Andrzej; Brewczyk, Mirosław; Gajda, Mariusz; Sacha, Krzysztof

    2016-08-01

    Eigenstates of Bose particles with repulsive contact interactions in one-dimensional space with periodic boundary conditions can be found with the help of the Bethe ansatz. The type II excitation spectrum identified by E. H. Lieb, reproduces the dispersion relation of dark solitons in the mean-field approach. The corresponding eigenstates possess translational symmetry which can be broken in measurements of positions of particles. We analyze emergence of single and double solitons in the course of the measurements and investigate dynamics of the system. In the weak interaction limit, the system follows the mean-field prediction for a short period of time. Long time evolution reveals many-body effects that are related to an increasing uncertainty of soliton positions. In the strong interaction regime particles behave like impenetrable bosons. Then, the probability densities in the configuration space become identical to the probabilities of noninteracting fermions but the wave functions themselves remember the original Bose statistics. Especially, the phase flips that are key signatures of the solitons in the weak interaction limit, can be observed in the time evolution of the strongly interacting bosons.

  16. Implementation of Single-Shot Ellipsometry on Gas Gun Experiments

    NASA Astrophysics Data System (ADS)

    Grant, Sean; Ao, Tommy; Bernstein, Aaron; Davis, Jean-Paul; Ditmire, Todd; Dolan, Daniel; Lin, Jung-Fu; Seagle, Christopher

    2015-06-01

    We have built and implemented a time-resolved ellipsometry diagnostic for dynamic testing at Sandia National Laboratories. This diagnostic measures refractive index of a sample under dynamic conditions with a time resolution of a few nanoseconds. We show and discuss results from our first dynamic experiments on a gas gun. Future work will study geophysical materials under relevant pressure-temperature conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2015-0376 A.

  17. Deterministic phase encoding encryption in single shot digital holography

    NASA Astrophysics Data System (ADS)

    Chen, G.-L.; Yang, W.-K.; Wang, J. C.; Chang, C.-C.

    2008-11-01

    We demonstrate a deterministic phase-encoded encryption system based on the digital holography and adopted a lenticular lens array (LLA) sheet as a phase modulator. In the proposed scheme the holographic patterns of encrypted images are captured digitally by a digital CCD. This work also adopt a novel, simple and effective technique that is used to suppress numerically the major blurring caused by the zero-order image in the numerical reconstruction. The decryption key is acquired as a digital hologram, called the key hologram. Therefore, the retrieval of the original information can be achieved by multiplying the encrypted hologram with a numerical generated phase-encoded wave. The storage and transmission of all holograms can be carried out by all-digital means. Simulation and experimental results demonstrate that the proposed approach can be operated in single procedure only and represent the satisfactory decrypted image. Finally, rotating and shifting the LLA is applied to investigate the tolerance of decryption to demonstrate the feasibility in the holographic encryption, as well as can also be used to provide the higher security.

  18. Single shot telecentricity measurement by Fourier space grid separation.

    PubMed

    Lorbeer, Raoul-Amadeus; Hitzemann, Moritz; Heidrich, Marko; Antonopoulos, Georgios; Ripken, Tammo; Meyer, Heiko

    2015-03-01

    The experimental documentation of the properties of an optical system represents a particular challenge. Besides the measurement of focal quality and field distortions, telecentric systems have to yield a parallel beam propagation direction. In this paper we propose a method to test, document and optimize the telecentricity of a laser scanning system by scanning two crossed polka dot beam splitters at once. By separating both beam splitters in Fourier space we were able to detect tilting angles below 2 · 10(-3) rad for four different laser wavelengths within the same optical system. By this we determined the optimum system parameters for our scanning laser optical tomography (SLOT) setup. PMID:25836878

  19. Performance Analyses of 38 kWe Turbo-Machine Unit for Space Reactor Power Systems

    NASA Astrophysics Data System (ADS)

    Gallo, Bruno M.; El-Genk, Mohamed S.

    2008-01-01

    This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to 45 krpm, variable reactor thermal power and system pressure, and fixed turbine and compressor inlet temperatures of 1144 K and 400 K. The analyses used a detailed turbo-machine model developed at the University of New Mexico that accounts for the various energy losses in the compressor and turbine and the effect of compressibility of the He-Xe (40 mole/g) working fluid with increased flow rate. The model also accounts for the changes in the physical and transport properties of the working fluid with temperature and pressure. Results show that a unit efficiency of 24.5% is achievable at rotation speed of 45 krpm and system pressure of 0.75 MPa, assuming shaft and electrical generator efficiencies of 86.7% and 90%. The corresponding net electric power output of the unit is 38.5 kWe, the flow rate of the working fluid is 1.667 kg/s, the pressure ratio and polytropic efficiency for the compressor are 1.60 and 83.1%, and 1.51 and 88.3% for the turbine.

  20. The Case for Distributed Engine Control in Turbo-Shaft Engine Systems

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Paluszewski, Paul J.; Storey, William; Smith, Bert J.

    2009-01-01

    The turbo-shaft engine is an important propulsion system used to power vehicles on land, sea, and in the air. As the power plant for many high performance helicopters, the characteristics of the engine and control are critical to proper vehicle operation as well as being the main determinant to overall vehicle performance. When applied to vertical flight, important distinctions exist in the turbo-shaft engine control system due to the high degree of dynamic coupling between the engine and airframe and the affect on vehicle handling characteristics. In this study, the impact of engine control system architecture is explored relative to engine performance, weight, reliability, safety, and overall cost. Comparison of the impact of architecture on these metrics is investigated as the control system is modified from a legacy centralized structure to a more distributed configuration. A composite strawman system which is typical of turbo-shaft engines in the 1000 to 2000 hp class is described and used for comparison. The overall benefits of these changes to control system architecture are assessed. The availability of supporting technologies to achieve this evolution is also discussed.

  1. Validation of Heat Transfer and Film Cooling Capabilities of the 3-D RANS Code TURBO

    NASA Technical Reports Server (NTRS)

    Shyam, Vikram; Ameri, Ali; Chen, Jen-Ping

    2010-01-01

    The capabilities of the 3-D unsteady RANS code TURBO have been extended to include heat transfer and film cooling applications. The results of simulations performed with the modified code are compared to experiment and to theory, where applicable. Wilcox s k-turbulence model has been implemented to close the RANS equations. Two simulations are conducted: (1) flow over a flat plate and (2) flow over an adiabatic flat plate cooled by one hole inclined at 35 to the free stream. For (1) agreement with theory is found to be excellent for heat transfer, represented by local Nusselt number, and quite good for momentum, as represented by the local skin friction coefficient. This report compares the local skin friction coefficients and Nusselt numbers on a flat plate obtained using Wilcox's k-model with the theory of Blasius. The study looks at laminar and turbulent flows over an adiabatic flat plate and over an isothermal flat plate for two different wall temperatures. It is shown that TURBO is able to accurately predict heat transfer on a flat plate. For (2) TURBO shows good qualitative agreement with film cooling experiments performed on a flat plate with one cooling hole. Quantitatively, film effectiveness is under predicted downstream of the hole.

  2. Performance Analyses of 38 kWe Turbo-Machine Unit for Space Reactor Power Systems

    SciTech Connect

    Gallo, Bruno M.; El-Genk, Mohamed S.

    2008-01-21

    This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to 45 krpm, variable reactor thermal power and system pressure, and fixed turbine and compressor inlet temperatures of 1144 K and 400 K. The analyses used a detailed turbo-machine model developed at University of New Mexico that accounts for the various energy losses in the compressor and turbine and the effect of compressibility of the He-Xe (40 mole/g) working fluid with increased flow rate. The model also accounts for the changes in the physical and transport properties of the working fluid with temperature and pressure. Results show that a unit efficiency of 24.5% is achievable at rotation speed of 45 krpm and system pressure of 0.75 MPa, assuming shaft and electrical generator efficiencies of 86.7% and 90%. The corresponding net electric power output of the unit is 38.5 kWe, the flow rate of the working fluid is 1.667 kg/s, the pressure ratio and polytropic efficiency for the compressor are 1.60 and 83.1%, and 1.51 and 88.3% for the turbine.

  3. Turbo Codes with Modified Code Matched Interleaver for Coded-Cooperation in Half-Duplex Wireless Relay Networks

    NASA Astrophysics Data System (ADS)

    Ejaz, Saqib; Yang, Feng-Fan

    2015-03-01

    The parallel encoding and decoding structure of turbo codes makes them natural candidate for coded-cooperative scenarios. In this paper, we focus on one of the key components of turbo codes i.e., interleaver, and analyze its effect on the performance of coded-cooperative communication. The impact of an interleaver on the overall performance of cooperative systems depends on the type of an interleaver and its location in the cooperative encoding scheme. We consider code matched interleaver (CMI) as an optimum choice and present its role in a coded-cooperation scenario. The search and convergence of CMI for long interleaver sizes is an issue; therefore, a modification in the search conditions is included without any compromise on the performance of CMI. We also present analytical method to determine maximum S-constraint length for a CMI design. Further, we analyze the performance of two different encoding schemes of turbo codes, i.e., distributed turbo code (DTC) and distributed multiple turbo code (DMTC) after inclusion of CMI. Monte Carlo simulations show that CMI increases the diversity gain relative to other conventional interleavers such as uniform random interleaver. The channel is assumed to be Rayleigh fading among all communication nodes.

  4. Validation of rapid velocity encoded cine imaging of a dynamically complex flow field using turbo block regional interpolation scheme for k space.

    PubMed

    Kortright, E; Doyle, M; Anayiotos, A S; Walsh, E G; Fuisz, A R; Pohost, G M

    2001-02-01

    Block regional interpolation scheme for k space (BRISK) is a sparse sampling approach to allow rapid magnetic resonance imaging of dynamic events. Rapid velocity encoded cine (VEC) imaging with Turbo BRISK is potentially an important clinical diagnostic technique for cardiovascular diseases. Previously we applied BRISK and Turbo BRISK to imaging pulsatile flow in a straight tube. To evaluate the capabilities of Turbo BRISK imaging in more complex dynamic flow fields such as might exist in the human vasculature, an in vitro curved tube model, similar in geometry to the aortic arch, was fabricated and imaged under pulsatile flow conditions. Velocity maps were obtained using conventional VEC and Turbo BRISK (turbo factors 1 through 5). Comparison of the flow fields obtained with each higher order turbo factor showed excellent agreement with conventional VEC with minimal loss of information. Similarly, flow maps showed good agreement with the profiles from a laser Doppler velocimetry model. Turbo-5 BRISK, for example, allowed a 94% savings in imaging time, reducing the conventional imaging time from over 8 min to a near breath-hold imaging period of 31 s. Turbo BRISK shows excellent promise toward the development of a clinical tool to evaluate complex dynamic intravascular flow fields.

  5. An Off-Grid Turbo Channel Estimation Algorithm for Millimeter Wave Communications.

    PubMed

    Han, Lingyi; Peng, Yuexing; Wang, Peng; Li, Yonghui

    2016-01-01

    The bandwidth shortage has motivated the exploration of the millimeter wave (mmWave) frequency spectrum for future communication networks. To compensate for the severe propagation attenuation in the mmWave band, massive antenna arrays can be adopted at both the transmitter and receiver to provide large array gains via directional beamforming. To achieve such array gains, channel estimation (CE) with high resolution and low latency is of great importance for mmWave communications. However, classic super-resolution subspace CE methods such as multiple signal classification (MUSIC) and estimation of signal parameters via rotation invariant technique (ESPRIT) cannot be applied here due to RF chain constraints. In this paper, an enhanced CE algorithm is developed for the off-grid problem when quantizing the angles of mmWave channel in the spatial domain where off-grid problem refers to the scenario that angles do not lie on the quantization grids with high probability, and it results in power leakage and severe reduction of the CE performance. A new model is first proposed to formulate the off-grid problem. The new model divides the continuously-distributed angle into a quantized discrete grid part, referred to as the integral grid angle, and an offset part, termed fractional off-grid angle. Accordingly, an iterative off-grid turbo CE (IOTCE) algorithm is proposed to renew and upgrade the CE between the integral grid part and the fractional off-grid part under the Turbo principle. By fully exploiting the sparse structure of mmWave channels, the integral grid part is estimated by a soft-decoding based compressed sensing (CS) method called improved turbo compressed channel sensing (ITCCS). It iteratively updates the soft information between the linear minimum mean square error (LMMSE) estimator and the sparsity combiner. Monte Carlo simulations are presented to evaluate the performance of the proposed method, and the results show that it enhances the angle detection

  6. An Off-Grid Turbo Channel Estimation Algorithm for Millimeter Wave Communications.

    PubMed

    Han, Lingyi; Peng, Yuexing; Wang, Peng; Li, Yonghui

    2016-09-22

    The bandwidth shortage has motivated the exploration of the millimeter wave (mmWave) frequency spectrum for future communication networks. To compensate for the severe propagation attenuation in the mmWave band, massive antenna arrays can be adopted at both the transmitter and receiver to provide large array gains via directional beamforming. To achieve such array gains, channel estimation (CE) with high resolution and low latency is of great importance for mmWave communications. However, classic super-resolution subspace CE methods such as multiple signal classification (MUSIC) and estimation of signal parameters via rotation invariant technique (ESPRIT) cannot be applied here due to RF chain constraints. In this paper, an enhanced CE algorithm is developed for the off-grid problem when quantizing the angles of mmWave channel in the spatial domain where off-grid problem refers to the scenario that angles do not lie on the quantization grids with high probability, and it results in power leakage and severe reduction of the CE performance. A new model is first proposed to formulate the off-grid problem. The new model divides the continuously-distributed angle into a quantized discrete grid part, referred to as the integral grid angle, and an offset part, termed fractional off-grid angle. Accordingly, an iterative off-grid turbo CE (IOTCE) algorithm is proposed to renew and upgrade the CE between the integral grid part and the fractional off-grid part under the Turbo principle. By fully exploiting the sparse structure of mmWave channels, the integral grid part is estimated by a soft-decoding based compressed sensing (CS) method called improved turbo compressed channel sensing (ITCCS). It iteratively updates the soft information between the linear minimum mean square error (LMMSE) estimator and the sparsity combiner. Monte Carlo simulations are presented to evaluate the performance of the proposed method, and the results show that it enhances the angle detection

  7. Serial-Turbo-Trellis-Coded Modulation with Rate-1 Inner Code

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Pollara, Fabrizio

    2004-01-01

    Serially concatenated turbo codes have been proposed to satisfy requirements for low bit- and word-error rates and for low (in comparison with related previous codes) complexity of coding and decoding algorithms and thus low complexity of coding and decoding circuitry. These codes are applicable to such high-level modulations as octonary phase-shift keying (8PSK) and 16-state quadrature amplitude modulation (16QAM); the signal product obtained by applying one of these codes to one of these modulations is denoted, generally, as serially concatenated trellis-coded modulation (SCTCM). These codes could be particularly beneficial for communication systems that must be designed and operated subject to limitations on bandwidth and power. Some background information is prerequisite to a meaningful summary of this development. Trellis-coded modulation (TCM) is now a well-established technique in digital communications. A turbo code combines binary component codes (which typically include trellis codes) with interleaving. A turbo code of the type that has been studied prior to this development is composed of parallel concatenated convolutional codes (PCCCs) implemented by two or more constituent systematic encoders joined through one or more interleavers. The input information bits feed the first encoder and, after having been scrambled by the interleaver, enter the second encoder. A code word of a parallel concatenated code consists of the input bits to the first encoder followed by the parity check bits of both encoders. The suboptimal iterative decoding structure for such a code is modular, and consists of a set of concatenated decoding modules one for each constituent code connected through an interleaver identical to the one in the encoder side. Each decoder performs weighted soft decoding of the input sequence. PCCCs yield very large coding gains at the cost of a reduction in the data rate and/or an increase in bandwidth.

  8. Small, high-speed bearing technology for cryogenic turbo-pumps

    NASA Technical Reports Server (NTRS)

    Winn, L. W.; Eusepi, M. W.; Smalley, A. J.

    1974-01-01

    The design of 20-mm bore ball bearings is described for cryogenic turbo-machinery applications, operating up to speeds of 120,000 rpm. A special section is included on the design of hybrid bearings. Each hybrid bearing is composed of a ball bearing in series with a conventional pressurized fluid-film journal bearing. Full details are presented on the design of a test vehicle which possesses the capability of testing the above named bearings within the given speed range under externally applied radial and axial loads.

  9. Quiet High Speed Fan (QHSF) Flutter Calculations Using the TURBO Code

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh; Keith, Theo G., Jr.; Min, James B.; Mehmed, Oral

    2006-01-01

    A scale model of the NASA/Honeywell Engines Quiet High Speed Fan (QHSF) encountered flutter wind tunnel testing. This report documents aeroelastic calculations done for the QHSF scale model using the blade vibration capability of the TURBO code. Calculations at design speed were used to quantify the effect of numerical parameters on the aerodynamic damping predictions. This numerical study allowed the selection of appropriate values of these parameters, and also allowed an assessment of the variability in the calculated aerodynamic damping. Calculations were also done at 90 percent of design speed. The predicted trends in aerodynamic damping corresponded to those observed during testing.

  10. Wireless image transmission using turbo codes and optimal unequal error protection.

    PubMed

    Thomos, Nikolaos; Boulgouris, Nikolaos V; Strintzis, Michael G

    2005-11-01

    A novel image transmission scheme is proposed for the communication of set partitioning in hierarchical trees image streams over wireless channels. The proposed scheme employs turbo codes and Reed-Solomon codes in order to deal effectively with burst errors. An algorithm for the optimal unequal error protection of the compressed bitstream is also proposed and applied in conjunction with an inherently more efficient technique for product code decoding. The resulting scheme is tested for the transmission of images over wireless channels. Experimental evaluation clearly demonstrates the superiority of the proposed transmission system in comparison to well-known robust coding schemes.

  11. Syntax acquisition.

    PubMed

    Crain, Stephen; Thornton, Rosalind

    2012-03-01

    Every normal child acquires a language in just a few years. By 3- or 4-years-old, children have effectively become adults in their abilities to produce and understand endlessly many sentences in a variety of conversational contexts. There are two alternative accounts of the course of children's language development. These different perspectives can be traced back to the nature versus nurture debate about how knowledge is acquired in any cognitive domain. One perspective dates back to Plato's dialog 'The Meno'. In this dialog, the protagonist, Socrates, demonstrates to Meno, an aristocrat in Ancient Greece, that a young slave knows more about geometry than he could have learned from experience. By extension, Plato's Problem refers to any gap between experience and knowledge. How children fill in the gap in the case of language continues to be the subject of much controversy in cognitive science. Any model of language acquisition must address three factors, inter alia: 1. The knowledge children accrue; 2. The input children receive (often called the primary linguistic data); 3. The nonlinguistic capacities of children to form and test generalizations based on the input. According to the famous linguist Noam Chomsky, the main task of linguistics is to explain how children bridge the gap-Chomsky calls it a 'chasm'-between what they come to know about language, and what they could have learned from experience, even given optimistic assumptions about their cognitive abilities. Proponents of the alternative 'nurture' approach accuse nativists like Chomsky of overestimating the complexity of what children learn, underestimating the data children have to work with, and manifesting undue pessimism about children's abilities to extract information based on the input. The modern 'nurture' approach is often referred to as the usage-based account. We discuss the usage-based account first, and then the nativist account. After that, we report and discuss the findings of several

  12. Syntax acquisition.

    PubMed

    Crain, Stephen; Thornton, Rosalind

    2012-03-01

    Every normal child acquires a language in just a few years. By 3- or 4-years-old, children have effectively become adults in their abilities to produce and understand endlessly many sentences in a variety of conversational contexts. There are two alternative accounts of the course of children's language development. These different perspectives can be traced back to the nature versus nurture debate about how knowledge is acquired in any cognitive domain. One perspective dates back to Plato's dialog 'The Meno'. In this dialog, the protagonist, Socrates, demonstrates to Meno, an aristocrat in Ancient Greece, that a young slave knows more about geometry than he could have learned from experience. By extension, Plato's Problem refers to any gap between experience and knowledge. How children fill in the gap in the case of language continues to be the subject of much controversy in cognitive science. Any model of language acquisition must address three factors, inter alia: 1. The knowledge children accrue; 2. The input children receive (often called the primary linguistic data); 3. The nonlinguistic capacities of children to form and test generalizations based on the input. According to the famous linguist Noam Chomsky, the main task of linguistics is to explain how children bridge the gap-Chomsky calls it a 'chasm'-between what they come to know about language, and what they could have learned from experience, even given optimistic assumptions about their cognitive abilities. Proponents of the alternative 'nurture' approach accuse nativists like Chomsky of overestimating the complexity of what children learn, underestimating the data children have to work with, and manifesting undue pessimism about children's abilities to extract information based on the input. The modern 'nurture' approach is often referred to as the usage-based account. We discuss the usage-based account first, and then the nativist account. After that, we report and discuss the findings of several

  13. Turbo-Brayton cryocooler technology for low-temperature space applications

    NASA Astrophysics Data System (ADS)

    Zagarola, Mark V.; Breedlove, Jeffrey F.; McCormick, John A.; Swift, Walter L.

    2003-03-01

    High performance, low temperature cryocoolers are being developed for future space-borne telescopes and instruments. To meet mission objectives, these coolers must be compact, lightweight, have low input power, operate reliably for 5-10 years, and produce no disturbances that would affect the pointing accuracy of the instruments. This paper describes progress in the development of turbo-Brayton cryocoolers addressing cooling in the 5 K to 20 K temperature range for loads of up to 300 mW. The key components for these cryocoolers are the miniature, high-speed turbomachines and the high performance recuperative heat exchangers. The turbomachines use gas-bearings to support the low mass, high speed rotors, resulting in negligible vibration and long life. Precision fabrication techniques are used to produce the necessary micro-scale geometric features that provide for high cycle efficiencies at these reduced sizes. Turbo-Brayton cryocoolers for higher temperatures and loads have been successfully developed for space applications. For efficient operation at low temperatures and capacities, advances in the core technologies have been pursued. Performance test results of a new, low poer compressor will be presented, and early cryogenic test results on a low temperature expansion turbine will be discussed. Projections for several low temperature cooler configurations are summarized.

  14. Sub-cooled liquid nitrogen cryogenic system with neon turbo-refrigerator for HTS power equipment

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Hirai, H.; Nara, N.; Ozaki, S.; Hirokawa, M.; Eguchi, T.; Hayashi, H.; Iwakuma, M.; Shiohara, Y.

    2014-01-01

    We developed a prototype sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The system consists of a neon turbo-Brayton refrigerator with a LN sub-cooler and LN circulation pump unit. The neon refrigerator has more than 2 kW cooling power at 65 K. The LN sub-cooler is a plate-fin type heat exchanger and is installed in a refrigerator cold box. In order to carry out the system performance tests, a dummy cryostat having an electric heater was set instead of a HTS power equipment. Sub-cooled LN is delivered into the sub-cooler by the LN circulation pump and cooled within it. After the sub-cooler, sub-cooled LN goes out from the cold box to the dummy cryostat, and comes back to the pump unit. The system can control an outlet sub-cooled LN temperature by adjusting refrigerator cooling power. The refrigerator cooling power is automatically controlled by the turbo-compressor rotational speed. In the performance tests, we increased an electric heater power from 200 W to 1300 W abruptly. We confirmed the temperature fluctuation was about ±1 K. We show the cryogenic system details and performance test results in this paper.

  15. Design and Development of a 200-kW Turbo-Electric Distributed Propulsion Testbed

    NASA Technical Reports Server (NTRS)

    Papathakis, Kurt V.; Kloesel, Kurt J.; Lin, Yohan; Clarke, Sean; Ediger, Jacob J.; Ginn, Starr

    2016-01-01

    The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center (AFRC) (Edwards, California) is developing a Hybrid-Electric Integrated Systems Testbed (HEIST) Testbed as part of the HEIST Project, to study power management and transition complexities, modular architectures, and flight control laws for turbo-electric distributed propulsion technologies using representative hardware and piloted simulations. Capabilities are being developed to assess the flight readiness of hybrid electric and distributed electric vehicle architectures. Additionally, NASA will leverage experience gained and assets developed from HEIST to assist in flight-test proposal development, flight-test vehicle design, and evaluation of hybrid electric and distributed electric concept vehicles for flight safety. The HEIST test equipment will include three trailers supporting a distributed electric propulsion wing, a battery system and turbogenerator, dynamometers, and supporting power and communication infrastructure, all connected to the AFRC Core simulation. Plans call for 18 high performance electric motors that will be powered by batteries and the turbogenerator, and commanded by a piloted simulation. Flight control algorithms will be developed on the turbo-electric distributed propulsion system.

  16. Investigating Second Language Acquisition.

    ERIC Educational Resources Information Center

    Jordens, Peter, Ed.; Lalleman, Josine, Ed.

    Essays in second language acquisition include: "The State of the Art in Second Language Acquisition Research" (Josine Lalleman); "Crosslinguistic Influence with Special Reference to the Acquisition of Grammar" (Michael Sharwood Smith); "Second Language Acquisition by Adult Immigrants: A Multiple Case Study of Turkish and Moroccan Learners of…

  17. Novel high-temperature reactors for in situ studies of three-way catalysts using turbo-XAS.

    PubMed

    Guilera, Gemma; Gorges, Bernard; Pascarelli, Sakura; Vitoux, Hugo; Newton, Mark A; Prestipino, Carmelo; Nagai, Yasutaka; Hara, Naoyuki

    2009-09-01

    Two novel high-temperature reactors for in situ X-ray absorption spectroscopy (XAS) measurements in fluorescence are presented, each of them being optimized for a particular purpose. The powerful combination of these reactors with the turbo-XAS technique used in a dispersive-XAS beamline permits the study of commercial three-way catalysts under realistic gas composition and temporal conditions.

  18. The Effect of Classic and Web Based Educational Application, Applied for Turbo Pascal Lesson, on Student Success Level

    ERIC Educational Resources Information Center

    Bintas, Jale; Barut, Asim

    2008-01-01

    The aim of research is to compare difference between tenth class students and determine their level of success about classic and web based educational applications of Turbo Pascal lesson. This research was applied to 10 A and 10 TLB students of Izmir Karsikaya Anatolian Technical and industrial high school computer department in second term of…

  19. Two high-density recording methods with run-length limited turbo code for holographic data storage system

    NASA Astrophysics Data System (ADS)

    Nakamura, Yusuke; Hoshizawa, Taku

    2016-09-01

    Two methods for increasing the data capacity of a holographic data storage system (HDSS) were developed. The first method is called “run-length-limited (RLL) high-density recording”. An RLL modulation has the same effect as enlarging the pixel pitch; namely, it optically reduces the hologram size. Accordingly, the method doubles the raw-data recording density. The second method is called “RLL turbo signal processing”. The RLL turbo code consists of \\text{RLL}(1,∞ ) trellis modulation and an optimized convolutional code. The remarkable point of the developed turbo code is that it employs the RLL modulator and demodulator as parts of the error-correction process. The turbo code improves the capability of error correction more than a conventional LDPC code, even though interpixel interference is generated. These two methods will increase the data density 1.78-fold. Moreover, by simulation and experiment, a data density of 2.4 Tbit/in.2 is confirmed.

  20. Empirical study of classification process for two-stage turbo air classifier in series

    NASA Astrophysics Data System (ADS)

    Yu, Yuan; Liu, Jiaxiang; Li, Gang

    2013-05-01

    The suitable process parameters for a two-stage turbo air classifier are important for obtaining the ultrafine powder that has a narrow particle-size distribution, however little has been published internationally on the classification process for the two-stage turbo air classifier in series. The influence of the process parameters of a two-stage turbo air classifier in series on classification performance is empirically studied by using aluminum oxide powders as the experimental material. The experimental results show the following: 1) When the rotor cage rotary speed of the first-stage classifier is increased from 2 300 r/min to 2 500 r/min with a constant rotor cage rotary speed of the second-stage classifier, classification precision is increased from 0.64 to 0.67. However, in this case, the final ultrafine powder yield is decreased from 79% to 74%, which means the classification precision and the final ultrafine powder yield can be regulated through adjusting the rotor cage rotary speed of the first-stage classifier. 2) When the rotor cage rotary speed of the second-stage classifier is increased from 2 500 r/min to 3 100 r/min with a constant rotor cage rotary speed of the first-stage classifier, the cut size is decreased from 13.16 μm to 8.76 μm, which means the cut size of the ultrafine powder can be regulated through adjusting the rotor cage rotary speed of the second-stage classifier. 3) When the feeding speed is increased from 35 kg/h to 50 kg/h, the "fish-hook" effect is strengthened, which makes the ultrafine powder yield decrease. 4) To weaken the "fish-hook" effect, the equalization of the two-stage wind speeds or the combination of a high first-stage wind speed with a low second-stage wind speed should be selected. This empirical study provides a criterion of process parameter configurations for a two-stage or multi-stage classifier in series, which offers a theoretical basis for practical production.

  1. Language Acquisition without an Acquisition Device

    ERIC Educational Resources Information Center

    O'Grady, William

    2012-01-01

    Most explanatory work on first and second language learning assumes the primacy of the acquisition phenomenon itself, and a good deal of work has been devoted to the search for an "acquisition device" that is specific to humans, and perhaps even to language. I will consider the possibility that this strategy is misguided and that language…

  2. Performance potential of air turbo-ramjet employing supersonic through-flow fan

    NASA Technical Reports Server (NTRS)

    Kepler, C. E.; Champagne, G. A.

    1989-01-01

    A study was conducted to assess the performance potential of a supersonic through-flow fan in an advanced engine designed to power a Mach-5 cruise vehicle. It included a preliminary evaluation of fan performance requirements and the desirability of supersonic versus subsonic combustion, the design and performance of supersonic fans, and the conceptual design of a single-pass air-turbo-rocket/ramjet engine for a Mach 5 cruise vehicle. The study results showed that such an engine could provide high thrust over the entire speed range from sea-level takeoff to Mach 5 cruise, especially over the transonic speed range, and high fuel specific impulse at the Mach 5 cruise condition, with the fan windmilling.

  3. Computational Aero-acoustics As a Tool For Turbo-machinery Noise Reduction

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.

    2003-01-01

    This talk will provide an overview of the field of computational aero-acoustics and its use in fan noise prediction. After a brief history of computational fluid dynamics, some of the recent developments in computational aero-acoustics will be explored. Computational issues concerning sound wave production, propagation, and reflection in practical turbo-machinery applications will be discussed including: (a) High order/High Resolution Numerical Techniques. (b) High Resolution Boundary Conditions. [c] MIMD Parallel Computing. [d] Form of Governing Equations Useful for Simulations. In addition, the basic design of our Broadband Analysis Stator Simulator (BASS) code and its application to a 2 D rotor wake-stator interaction will be shown. An example of the noise produced by the wakes from a rotor impinging upon a stator cascade will be shown.

  4. Soft-Output Decoding Algorithms in Iterative Decoding of Turbo Codes

    NASA Technical Reports Server (NTRS)

    Benedetto, S.; Montorsi, G.; Divsalar, D.; Pollara, F.

    1996-01-01

    In this article, we present two versions of a simplified maximum a posteriori decoding algorithm. The algorithms work in a sliding window form, like the Viterbi algorithm, and can thus be used to decode continuously transmitted sequences obtained by parallel concatenated codes, without requiring code trellis termination. A heuristic explanation is also given of how to embed the maximum a posteriori algorithms into the iterative decoding of parallel concatenated codes (turbo codes). The performances of the two algorithms are compared on the basis of a powerful rate 1/3 parallel concatenated code. Basic circuits to implement the simplified a posteriori decoding algorithm using lookup tables, and two further approximations (linear and threshold), with a very small penalty, to eliminate the need for lookup tables are proposed.

  5. Theoretical and experimental studies of turbo product code with time diversity in free space optical communication.

    PubMed

    Han, Yaoqiang; Dang, Anhong; Ren, Yongxiong; Tang, Junxiong; Guo, Hong

    2010-12-20

    In free space optical communication (FSOC) systems, channel fading caused by atmospheric turbulence degrades the system performance seriously. However, channel coding combined with diversity techniques can be exploited to mitigate channel fading. In this paper, based on the experimental study of the channel fading effects, we propose to use turbo product code (TPC) as the channel coding scheme, which features good resistance to burst errors and no error floor. However, only channel coding cannot cope with burst errors caused by channel fading, interleaving is also used. We investigate the efficiency of interleaving for different interleaving depths, and then the optimum interleaving depth for TPC is also determined. Finally, an experimental study of TPC with interleaving is demonstrated, and we show that TPC with interleaving can significantly mitigate channel fading in FSOC systems.

  6. Evaluation of large girth LDPC codes for PMD compensation by turbo equalization.

    PubMed

    Minkov, Lyubomir L; Djordjevic, Ivan B; Xu, Lei; Wang, Ting; Kueppers, Franko

    2008-08-18

    Large-girth quasi-cyclic LDPC codes have been experimentally evaluated for use in PMD compensation by turbo equalization for a 10 Gb/s NRZ optical transmission system, and observing one sample per bit. Net effective coding gain improvement for girth-10, rate 0.906 code of length 11936 over maximum a posteriori probability (MAP) detector for differential group delay of 125 ps is 6.25 dB at BER of 10(-6). Girth-10 LDPC code of rate 0.8 outperforms the girth-10 code of rate 0.906 by 2.75 dB, and provides the net effective coding gain improvement of 9 dB at the same BER. It is experimentally determined that girth-10 LDPC codes of length around 15000 approach channel capacity limit within 1.25 dB.

  7. Soft-output decoding algorithms in iterative decoding of turbo codes

    NASA Technical Reports Server (NTRS)

    Benedetto, S.; Montorsi, G.; Divsalar, D.; Pollara, F.

    1996-01-01

    In this article, we present two versions of a simplified maximum a posteriori decoding algorithm. The algorithms work in a sliding window form, like the Viterbi algorithm, and can thus be used to decode continuously transmitted sequences obtained by parallel concatenated codes, without requiring code trellis termination. A heuristic explanation is also given of how to embed the maximum a posteriori algorithms into the iterative decoding of parallel concatenated codes (turbo codes). The performances of the two algorithms are compared on the basis of a powerful rate 1/3 parallel concatenated code. Basic circuits to implement the simplified a posteriori decoding algorithm using lookup tables, and two further approximations (linear and threshold), with a very small penalty, to eliminate the need for lookup tables are proposed.

  8. Use of Xenon Difluoride to Clean Hazardous By-Products in Ion Implanter Source Housings, Turbo Pumps, and Fore-Lines

    SciTech Connect

    Despres, J.; Chambers, B.; Bishop, S.; Kaim, R.; Letaj, S.; Sergi, S.; Sweeney, J.; Tang, Y.; Wilson, S.; Yedave, S.

    2011-01-07

    This paper describes the use of xenon difluoride to clean deposits in the source housing, source turbo pump, and source turbo pump fore-line of ion implanters. Xenon difluoride has previously been shown to be effective in increasing the lifetime of the ion source{sup 1,2} and this paper presents an extension of the technology to other areas within the tool. Process by-products that are deposited in the source housing, turbo pump, and turbo pump fore-line can not only pose productivity issues, in the case of coatings on insulators, but can also be flammable and toxic in the case of deposits formed within the turbo pump and fore-line. The results presented in this paper detail the initial successful examples of using xenon difluoride to clean these deposits.ATMI has shown that xenon difluoride is capable of cleaning an insulator in an ion implanter. Typically during use an insulator will become increasingly coated with deposits that could lead to productivity problems. By introducing xenon difluoride into the source housing the insulator residues were effectively cleaned in-situ, thereby extending the maintenance interval and resulting in significant consumable savings.Similar deposits that form in the turbo pump and fore-line could not only lead to production problems due to turbo pump failure or fore-line build-up, but pose significant health risks during the ex-situ cleaning process. Through internal testing ATMI has shown that xenon difluoride is able to clean phosphorus and germanium deposits located within a turbo pump. Additionally, testing has demonstrated that the turbo pump fore-line can be cleaned in-situ without the need to remove these components, thereby virtually eliminating the possibility of fires. The cleaning reaction progress and by-products were monitored using FTIR spectrometry and thermocouples.In order to efficiently clean the source housing, turbo pump, and turbo pump fore-line xenon difluoride delivery must be optimized. This paper also

  9. Preprocessor that Enables the Use of GridProTM Grids for Unsteady Reynolds-Averaged Navier-Stokes Code TURBO

    NASA Technical Reports Server (NTRS)

    Shyam, Vikram

    2010-01-01

    A preprocessor for the Computational Fluid Dynamics (CFD) code TURBO has been developed and tested. The preprocessor converts grids produced by GridPro (Program Development Company (PDC)) into a format readable by TURBO and generates the necessary input files associated with the grid. The preprocessor also generates information that enables the user to decide how to allocate the computational load in a multiple block per processor scenario.

  10. Operational Safety Assessment of Turbo Generators with Wavelet Rényi Entropy from Sensor-Dependent Vibration Signals

    PubMed Central

    Zhang, Xiaoli; Wang, Baojian; Chen, Xuefeng

    2015-01-01

    With the rapid development of sensor technology, various professional sensors are installed on modern machinery to monitor operational processes and assure operational safety, which play an important role in industry and society. In this work a new operational safety assessment approach with wavelet Rényi entropy utilizing sensor-dependent vibration signals is proposed. On the basis of a professional sensor and the corresponding system, sensor-dependent vibration signals are acquired and analyzed by a second generation wavelet package, which reflects time-varying operational characteristic of individual machinery. Derived from the sensor-dependent signals’ wavelet energy distribution over the observed signal frequency range, wavelet Rényi entropy is defined to compute the operational uncertainty of a turbo generator, which is then associated with its operational safety degree. The proposed method is applied in a 50 MW turbo generator, whereupon it is proved to be reasonable and effective for operation and maintenance. PMID:25894934

  11. Single-carrier frequency-domain turbo equalization without cyclic prefix or zero padding for underwater acoustic communications.

    PubMed

    Wang, Longbao; Tao, Jun; Zheng, Yahong Rosa

    2012-12-01

    A frequency-domain turbo equalization (FDTE) scheme without cyclic prefix (CP) or zero padding is proposed for single-carrier, multiple-input-multiple-output underwater acoustic communication. In the first iteration of the FDTE, the received continuous data stream is divided into consecutive blocks and a combined inter-block-interference (IBI) cancellation and overlapped windowing scheme is used to diagonalize each data block for low-complexity detection in the frequency domain. Since the second iteration, IBI cancellation and CP reconstruction are applied on each block to enable effective symbol detection. This work extends the authors' previous work on frequency-domain hard-decision equalization to soft-decision turbo equalization so that it not only retains high data transmission efficiency, but also improves the bit error rate performance with slightly increased complexity due to multiple iterations. Its feasibility and effectiveness have been tested by field trial data from the ACOMM09 underwater communication experiment. PMID:23231110

  12. Operational safety assessment of turbo generators with wavelet Rényi entropy from sensor-dependent vibration signals.

    PubMed

    Zhang, Xiaoli; Wang, Baojian; Chen, Xuefeng

    2015-04-16

    With the rapid development of sensor technology, various professional sensors are installed on modern machinery to monitor operational processes and assure operational safety, which play an important role in industry and society. In this work a new operational safety assessment approach with wavelet Rényi entropy utilizing sensor-dependent vibration signals is proposed. On the basis of a professional sensor and the corresponding system, sensor-dependent vibration signals are acquired and analyzed by a second generation wavelet package, which reflects time-varying operational characteristic of individual machinery. Derived from the sensor-dependent signals' wavelet energy distribution over the observed signal frequency range, wavelet Rényi entropy is defined to compute the operational uncertainty of a turbo generator, which is then associated with its operational safety degree. The proposed method is applied in a 50 MW turbo generator, whereupon it is proved to be reasonable and effective for operation and maintenance.

  13. Single-carrier frequency-domain turbo equalization without cyclic prefix or zero padding for underwater acoustic communications.

    PubMed

    Wang, Longbao; Tao, Jun; Zheng, Yahong Rosa

    2012-12-01

    A frequency-domain turbo equalization (FDTE) scheme without cyclic prefix (CP) or zero padding is proposed for single-carrier, multiple-input-multiple-output underwater acoustic communication. In the first iteration of the FDTE, the received continuous data stream is divided into consecutive blocks and a combined inter-block-interference (IBI) cancellation and overlapped windowing scheme is used to diagonalize each data block for low-complexity detection in the frequency domain. Since the second iteration, IBI cancellation and CP reconstruction are applied on each block to enable effective symbol detection. This work extends the authors' previous work on frequency-domain hard-decision equalization to soft-decision turbo equalization so that it not only retains high data transmission efficiency, but also improves the bit error rate performance with slightly increased complexity due to multiple iterations. Its feasibility and effectiveness have been tested by field trial data from the ACOMM09 underwater communication experiment.

  14. Q-ball imaging with PROPELLER EPI acquisition.

    PubMed

    Chou, Ming-Chung; Huang, Teng-Yi; Chung, Hsiao-Wen; Hsieh, Tsyh-Jyi; Chang, Hing-Chiu; Chen, Cheng-Yu

    2013-12-01

    Q-ball imaging (QBI) is an imaging technique that is capable of resolving intravoxel fiber crossings; however, the signal readout based on echo-planar imaging (EPI) introduces geometric distortions in the presence of susceptibility gradients. This study proposes an imaging technique that reduces susceptibility distortions in QBI by short-axis PROPELLER EPI acquisition. Conventional QBI and PROPELLER QBI data were acquired from two 3T MR scans of the brains of five healthy subjects. Prior to the PROPELLER reconstruction, residual distortions in single-blade low-resolution b0 and diffusion-weighted images (DWIs) were minimized by linear affine and nonlinear diffeomorphic demon registrations. Subsequently, the PROPELLER keyhole reconstruction was applied to the corrected DWIs to obtain high-resolution PROPELLER DWIs. The generalized fractional anisotropy and orientation distribution function maps contained fewer distortions in PROPELLER QBI than in conventional QBI, and the fiber tracts more closely matched the brain anatomy depicted by turbo spin-echo (TSE) T2-weighted imaging (T2WI). Furthermore, for fixed T(E), PROPELLER QBI enabled a shorter scan time than conventional QBI. We conclude that PROPELLER QBI can reduce susceptibility distortions without lengthening the acquisition time and is suitable for tracing neuronal fiber tracts in the human brain.

  15. FTMP data acquisition environment

    NASA Technical Reports Server (NTRS)

    Padilla, Peter A.

    1988-01-01

    The Fault-Tolerant Multi-Processing (FTMP) test-bed data acquisition environment is described. The performance of two data acquisition devices available in the test environment are estimated and compared. These estimated data rates are used as measures of the devices' capabilities. A new data acquisition device was developed and added to the FTMP environment. This path increases the data rate available by approximately a factor of 8, to 379 KW/S, while simplifying the experiment development process.

  16. Streamlined acquisition handbook

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA has always placed great emphasis on the acquisition process, recognizing it as among its most important activities. This handbook is intended to facilitate the application of streamlined acquisition procedures. The development of these procedures reflects the efforts of an action group composed of NASA Headquarters and center acquisition professionals. It is the intent to accomplish the real change in the acquisition process as a result of this effort. An important part of streamlining the acquisition process is a commitment by the people involved in the process to accomplishing acquisition activities quickly and with high quality. Too often we continue to accomplish work in 'the same old way' without considering available alternatives which would require no changes to regulations, approvals from Headquarters, or waivers of required practice. Similarly, we must be sensitive to schedule opportunities throughout the acquisition cycle, not just once the purchase request arrives at the procurement office. Techniques that have been identified as ways of reducing acquisition lead time while maintaining high quality in our acquisition process are presented.

  17. Quantification of multiple fault parameters in flexible turbo-generator systems with incomplete rundown vibration data

    NASA Astrophysics Data System (ADS)

    Lal, Mohit; Tiwari, Rajiv

    2013-12-01

    A turbo-generator system of the modern rotating machinery consists of the driver and driven shafts, which are coupled through flexible couplings and mounted on flexible bearings. Dynamic characterisation of vital machine elements of such rotating machinery is a challenging problem for reliable and accurate response predictions. In this paper, a key intention is to estimate the bearing and coupling dynamic parameters along with residual unbalances at predefined planes, and the misalignment forces and moments at the coupling based on the rundown vibration data. To tackle a practical difficulty of limited measurements and a numerical difficulty of the conventional dynamic condensation in the development of identification algorithm, a novel condensation technique has been implemented especially to overcome measurement of transverse rotational DOFs. Numerical examples are also presented to show the effectiveness of the proposed method. The measurement noise has been added in numerically simulated responses that are used in the present algorithm to identify the parameters and it is found to be robust. Modelling errors of few physical parameters are also considered and estimates are found to be very good.

  18. Aerodynamic Design and Numerical Analysis of Supersonic Turbine for Turbo Pump

    NASA Astrophysics Data System (ADS)

    Fu, Chao; Zou, Zhengping; Kong, Qingguo; Cheng, Honggui; Zhang, Weihao

    2016-09-01

    Supersonic turbine is widely used in the turbo pump of modern rocket. A preliminary design method for supersonic turbine has been developed considering the coupling effects of turbine and nozzle. Numerical simulation has been proceeded to validate the feasibility of the design method. As the strong shockwave reflected on the mixing plane, additional numerical simulated error would be produced by the mixing plane model in the steady CFD. So unsteady CFD is employed to investigate the aerodynamic performance of the turbine and flow field in passage. Results showed that the preliminary design method developed in this paper is suitable for designing supersonic turbine. This periodical variation of complex shockwave system influences the development of secondary flow, wake and shock-boundary layer interaction, which obviously affect the secondary loss in vane passage. The periodical variation also influences the strength of reflecting shockwave, which affects the profile loss in vane passage. Besides, high circumferential velocity at vane outlet and short blade lead to high radial pressure gradient, which makes the low kinetic energy fluid moves towards hub region and produces additional loss.

  19. Progress Towards a 6-10 K Turbo-Brayton Cryocooler

    NASA Astrophysics Data System (ADS)

    Zagarola, M. V.; Cragin, K. J.; Breedlove, J. J.; Davis, T. M.

    2006-04-01

    Turbomachine-based Brayton (turbo-Brayton) cryocoolers are an ideal option for long-duration space missions. Key attributes inherent to the technology are high reliability, extremely low vibration emittance, and flexible packaging and integration with instruments and spacecraft systems. The first space implementation of the technology was the NICMOS Cryocooler, which is a single-stage unit that was installed on the Hubble Space Telescope in March 2002. This cryocooler provides 7 W of cooling at 70 K and has been operating for 3.3 years (July 2005) without degradation in performance. New developments at Creare are focused on two-stage configurations with load temperatures as low as 6 K. The lower temperatures and loads have required advances in component technologies to meet aggressive targets for cryocooler mass, size and performance. The development of the electronics, compressors and intermediate turboalternator for a 6-10 K cryocooler are complete. This paper summarizes our accomplishments on the completed components, and reviews our progress towards the development of the remaining critical components, a lightweight recuperator and a high performance low temperature turboalternator.

  20. Acquisition of teleological descriptions

    NASA Astrophysics Data System (ADS)

    Franke, David W.

    1992-03-01

    Teleology descriptions capture the purpose of an entity, mechanism, or activity with which they are associated. These descriptions can be used in explanation, diagnosis, and design reuse. We describe a technique for acquiring teleological descriptions expressed in the teleology language TeD. Acquisition occurs during design by observing design modifications and design verification. We demonstrate the acquisition technique in an electronic circuit design.

  1. Quick Ride: Acquisition Overview

    NASA Technical Reports Server (NTRS)

    Adams, W. James

    1999-01-01

    Quick Ride is an outgrowth of rapid spacecraft acquisition. It provides a variety of low-cost, short lead time satellite rides for science instruments. Task order contracts with commercial firms will permit placing a order within 30 days. Secondary objectives include a demonstration of a FAR Part 12 commercial acquisition and the exploration of the use of on-ramps.

  2. Measurement and control system for cryogenic helium gas bearing turbo-expander experimental platform based on Siemens PLC S7-300

    SciTech Connect

    Li, J.; Xiong, L. Y.; Peng, N.; Dong, B.; Liu, L. Q.; Wang, P.

    2014-01-29

    An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. This turbo-expander experimental platform is designed for performance testing and experimental research on Helium turbo-expanders with different sizes from the liquid hydrogen temperature to the room temperature region. A measurement and control system based on Siemens PLC S7-300 for this turbo-expander experimental platform is developed. Proper sensors are selected to measure such parameters as temperature, pressure, rotation speed and air flow rate. All the collected data to be processed are transformed and transmitted to S7-300 CPU. Siemens S7-300 series PLC CPU315-2PN/DP is as master station and two sets of ET200M DP remote expand I/O is as slave station. Profibus-DP field communication is established between master station and slave stations. The upper computer Human Machine Interface (HMI) is compiled using Siemens configuration software WinCC V6.2. The upper computer communicates with PLC by means of industrial Ethernet. Centralized monitoring and distributed control is achieved. Experimental results show that this measurement and control system has fulfilled the test requirement for the turbo-expander experimental platform.

  3. Measurement and control system for cryogenic helium gas bearing turbo-expander experimental platform based on Siemens PLC S7-300

    NASA Astrophysics Data System (ADS)

    Li, J.; Xiong, L. Y.; Peng, N.; Dong, B.; Wang, P.; Liu, L. Q.

    2014-01-01

    An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. This turbo-expander experimental platform is designed for performance testing and experimental research on Helium turbo-expanders with different sizes from the liquid hydrogen temperature to the room temperature region. A measurement and control system based on Siemens PLC S7-300 for this turbo-expander experimental platform is developed. Proper sensors are selected to measure such parameters as temperature, pressure, rotation speed and air flow rate. All the collected data to be processed are transformed and transmitted to S7-300 CPU. Siemens S7-300 series PLC CPU315-2PN/DP is as master station and two sets of ET200M DP remote expand I/O is as slave station. Profibus-DP field communication is established between master station and slave stations. The upper computer Human Machine Interface (HMI) is compiled using Siemens configuration software WinCC V6.2. The upper computer communicates with PLC by means of industrial Ethernet. Centralized monitoring and distributed control is achieved. Experimental results show that this measurement and control system has fulfilled the test requirement for the turbo-expander experimental platform.

  4. STIS target acquisition

    NASA Technical Reports Server (NTRS)

    Kraemer, Steve; Downes, Ron; Katsanis, Rocio; Crenshaw, Mike; McGrath, Melissa; Robinson, Rich

    1997-01-01

    We describe the STIS autonomous target acquisition capabilities. We also present the results of dedicated tests executed as part of Cycle 7 calibration, following post-launch improvements to the Space Telescope Imaging Spectrograph (STIS) flight software. The residual pointing error from the acquisitions are < 0.5 CCD pixels, which is better than preflight estimates. Execution of peakups show clear improvement of target centering for slits of width 0.1 sec or smaller. These results may be used by Guest Observers in planning target acquisitions for their STIS programs.

  5. Interactive knowledge acquisition tools

    NASA Technical Reports Server (NTRS)

    Dudziak, Martin J.; Feinstein, Jerald L.

    1987-01-01

    The problems of designing practical tools to aid the knowledge engineer and general applications used in performing knowledge acquisition tasks are discussed. A particular approach was developed for the class of knowledge acquisition problem characterized by situations where acquisition and transformation of domain expertise are often bottlenecks in systems development. An explanation is given on how the tool and underlying software engineering principles can be extended to provide a flexible set of tools that allow the application specialist to build highly customized knowledge-based applications.

  6. CFD Study of Turbo-Ramjet Interactions in Hypersonic Airbreathing Propulsion System

    NASA Technical Reports Server (NTRS)

    Chang, Ing; Hunter, Louis G.

    1996-01-01

    Advanced airbreathing propulsion systems used in Mach 4-6 mission scenarios, usually involve turbo-ramjet configurations. As the engines transition from turbojet to ramjet, there is an operational envelope where both engines operate simultaneously. In the first phase of our study, an over/under nozzle configuration was analyzed. The two plumes from the turbojet and ramjet interact at the end of a common 2-D cowl, where they both reach an approximate Mach 3.0 condition and then jointly expand to Mach 3.6 at the common nozzle exit plane. For the problem analyzed, the turbojet engine operates at a higher nozzle pressure ratio than the ramjet, causes the turbojet plume overpowers the ramjet plume, deflecting it approximately 12 degrees downward and in turn the turbojet plume is deflected 6 degrees upward. In the process, shocks were formed at the deflections and a shear layer formed at the confluence of the two jets. This particular case was experimentally tested and the data were used to compare with a computational fluid dynamics (CFD) study using the PARC2D code. The CFD results were in good agreement with both static pressure distributions on the cowl separator and on nozzle walls. The thrust coefficients were also in reasonable agreement. In addition, inviscid relationships were developed around the confluence point, where the two exhaust jets meet, and these results compared favorably with the CFD results. In the second phase of our study, a 3-D CFD solution was generated to compare with the 2-D solution. The major difference between the 2-D and 3-D solutions was the interaction of the shock waves, generated by the plume interactions, on the sidewall. When a shock wave interacts with a sidewall and sidewall boundary layer, it is called a glancing shock sidewall interaction. These interactions entrain boundary layer flow down the shockline into a vortical flow pattern. The 3-D plots show the streamlines being entrained down the shockline. The pressure of the flow

  7. Numerical study on the spontaneous condensation flow in an air cryogenic turbo-expander using equilibrium and non-equilibrium models

    NASA Astrophysics Data System (ADS)

    Sun, Wan; Niu, Lu; Chen, Liang; Chen, Shuangtao; Zhang, Xingqun; Hou, Yu

    2016-01-01

    The difficulty of data measurement in cryogenic environments and the complicated mechanism of nucleation process have restricted the design of wet type turbo-expander for cryogenic liquid plants. In this paper, equilibrium and non-equilibrium models are used to model the spontaneous condensation flow in a cryogenic turbo-expander along the main stream passage including nozzle, impeller and diffuser. The comparison shows a distinct difference of the predicted wetness fraction distribution along the streamline between the equilibrium model and the non-equilibrium model. In non-equilibrium model, the distributions of supercooling and nucleation rate along the length of turbo-expander are given for the analysis of flow characteristics. The comparison of outlet wetness fraction with the experimental data is also provided for verification and discussion. Both the effects of the rotation on nucleation and the effects of the nucleation on flow along suction side of the impeller are investigated.

  8. Initial in vivo evaluation of the newly developed axial flow turbo pump with hydrodynamic bearings.

    PubMed

    Tanaka, Hideyuki; Tsukiya, Tomonori; Tatsumi, Eisuke; Mizuno, Toshihide; Hidaka, Tatsuya; Okubo, Takeshi; Osada, Toshiyuki; Miyamoto, Shinji; Taenaka, Yoshiyuki

    2011-03-01

    An implantable, compact rotary blood pump has been newly developed using an axial flow turbo pump with hydrodynamic bearings. The rotating impeller, which is hydrodynamically levitated with the assistance of repulsive magnetic force, has no contact with the inner surface of the pump. To evaluate the hemodynamic performance and biocompatibility, the pump was installed into four calves for up to 90 days. The pump was installed in the left heart bypass fashion, and placed paracorporeally in the first two calves and in the thoracic cavity in the other two calves. All calves received anticoagulation and antiaggregation therapy during the study. Aortic pressure, heart rate and pump-operating parameters were continuously measured. Hematologic and biochemical tests to evaluate anemia, hepato-renal function and the extent of hemolysis were performed on schedule. Each calf was killed at the termination of the experiments, and pathological analysis for the biocompatibility of the pump system was performed, including the thrombi in the device, emboli in the systemic organs and signs of infection. The pump stably produced a flow of 5 l/min. Each calf was supported for 78, 50, 90 and 90 days, respectively, with no incidence of hemorrhage, organ failure or significant hemolysis. No thrombus formation or mechanical wearing was observed inside the pump. There was no evidence of heat injury around the pump. Device-related infections were observed, but the severity of infection was mild in the implant case compared to the paracorporeal case. The pump demonstrated acceptable hemodynamic performance and biocompatibility in the initial in vivo testing.

  9. Quick screening of priority β-agonists in urine using automated TurboFlow™-LC/Exactive mass spectrometry.

    PubMed

    Bernsmann, T; Fürst, P; Godula, M

    2011-10-01

    This paper describes a method for the determination of priority β-agonists in urine based on a fully automated sample preparation procedure using an online TurboFlow™ chromatography clean-up step and determination with Orbitrap™ mass analyser technology. The principle of the method was the enrichment of the β-agonists after enzymatic hydrolysis overnight on a small column packed with a special stationary phase (TurboFlow™) while flushing away sample matrix and interfering compounds. Thereafter, the analytes were transferred onto an analytical column and detected by liquid chromatography/high-resolution mass spectrometry in full-scan mode at a resolution of R = 50,000 FWHM (full width at half maximum) and in higher energy collisional dissociation (HCD) scan mode at a resolving power of 10,000 FWHM. The optimisation of each step of the method, such as selection of the TurboFlow™ and analytical column as well as sample loading and elution parameters were performed using a standard solution containing salbutamol, clenbuterol and mabuterol at a concentration of 100 µg l(-1). The developed automated sample preparation significantly improved the throughput and efficiency of the previously used screening method and it resulted in a considerable reduction in analysis time. Validation experiments including 24 β-agonists in urine gave decision limits (CCα) between 0.05 and 0.35 µg l(-1). The repeatability of analyses for urine samples spiked at 0.5 µg l(-1) was within the range of 5-26% and recoveries for all compounds were within 89-107%.

  10. Computer simulation of the heavy-duty turbo-compounded diesel cycle for studies of engine efficiency and performance

    NASA Technical Reports Server (NTRS)

    Assanis, D. N.; Ekchian, J. A.; Heywood, J. B.; Replogle, K. K.

    1984-01-01

    Reductions in heat loss at appropriate points in the diesel engine which result in substantially increased exhaust enthalpy were shown. The concepts for this increased enthalpy are the turbocharged, turbocompounded diesel engine cycle. A computer simulation of the heavy duty turbocharged turbo-compounded diesel engine system was undertaken. This allows the definition of the tradeoffs which are associated with the introduction of ceramic materials in various parts of the total engine system, and the study of system optimization. The basic assumptions and the mathematical relationships used in the simulation of the model engine are described.

  11. Acquisition signal transmitter

    NASA Technical Reports Server (NTRS)

    Friedman, Morton L. (Inventor)

    1989-01-01

    An encoded information transmitter which transmits a radio frequency carrier that is amplitude modulated by a constant frequency waveform and thereafter amplitude modulated by a predetermined encoded waveform, the constant frequency waveform modulated carrier constituting an acquisition signal and the encoded waveform modulated carrier constituting an information bearing signal, the acquisition signal providing enhanced signal acquisition and interference rejection favoring the information bearing signal. One specific application for this transmitter is as a distress transmitter where a conventional, legislated audio tone modulated signal is transmitted followed first by the acquisition signal and then the information bearing signal, the information bearing signal being encoded with, among other things, vehicle identification data. The acquistion signal enables a receiver to acquire the information bearing signal where the received signal is low and/or where the received signal has a low signal-to-noise ratio in an environment where there are multiple signals in the same frequency band as the information bearing signal.

  12. Defense acquisition programs

    SciTech Connect

    Not Available

    1990-06-01

    The continuing instability in the overall defense budget and the recent changes in Eastern Europe are forcing DOD and the military services to reexamine the need, priority, and annual funding levels for many weapon system acquisition programs. GAO reviewed six weapon system acquisition programs that DOD was scheduled to make an acquisition milestone decision on during fiscal year 1991. Under milestone authorization, up to five years funding can be approved to cover the entire acquisition phase for either full-scale development or full-rate production. This report examines the Non-Line-of-Sight Missile, the Light Helicopter, the MK-50 Torpedo, the Sensor Fuzed Weapon, the Advanced Tactical Fighter, and the Joint Tactical Information Distribution System Class 2 Terminals.

  13. Documentation and knowledge acquisition

    NASA Technical Reports Server (NTRS)

    Rochowiak, Daniel; Moseley, Warren

    1990-01-01

    Traditional approaches to knowledge acquisition have focused on interviews. An alternative focuses on the documentation associated with a domain. Adopting a documentation approach provides some advantages during familiarization. A knowledge management tool was constructed to gain these advantages.

  14. Airborne data acquisition techniques

    SciTech Connect

    Arro, A.A.

    1980-01-01

    The introduction of standards on acceptable procedures for assessing building heat loss has created a dilemma for the contractor performing airborne thermographic surveys. These standards impose specifications on instrumentation, data acquisition, recording, interpretation, and presentation. Under the standard, the contractor has both the obligation of compliance and the requirement of offering his services at a reasonable price. This paper discusses the various aspects of data acquisition for airborne thermographic surveys and various techniques to reduce the costs of this operation. These techniques include the calculation of flight parameters for economical data acquisition, the selection and use of maps for mission planning, and the use of meteorological forecasts for flight scheduling and the actual execution of the mission. The proper consideration of these factors will result in a cost effective data acquisition and will place the contractor in a very competitive position in offering airborne thermographic survey services.

  15. Data acquisition system

    DOEpatents

    Shapiro, Stephen L.; Mani, Sudhindra; Atlas, Eugene L.; Cords, Dieter H. W.; Holbrook, Britt

    1997-01-01

    A data acquisition circuit for a particle detection system that allows for time tagging of particles detected by the system. The particle detection system screens out background noise and discriminate between hits from scattered and unscattered particles. The detection system can also be adapted to detect a wide variety of particle types. The detection system utilizes a particle detection pixel array, each pixel containing a back-biased PIN diode, and a data acquisition pixel array. Each pixel in the particle detection pixel array is in electrical contact with a pixel in the data acquisition pixel array. In response to a particle hit, the affected PIN diodes generate a current, which is detected by the corresponding data acquisition pixels. This current is integrated to produce a voltage across a capacitor, the voltage being related to the amount of energy deposited in the pixel by the particle. The current is also used to trigger a read of the pixel hit by the particle.

  16. HASTE sequence with parallel acquisition and T2 decay compensation: application to carotid artery imaging.

    PubMed

    Zhang, Ling; Kholmovski, Eugene G; Guo, Junyu; Choi, Seong-Eun Kim; Morrell, Glen R; Parker, Dennis L

    2009-01-01

    T2-weighted carotid artery images acquired using the turbo spin-echo (TSE) sequence frequently suffer from motion artifacts due to respiration and blood pulsation. The possibility of using HASTE sequence to achieve motion-free carotid images was investigated. The HASTE sequence suffers from severe blurring artifacts due to signal loss in later echoes due to T2 decay. Combining HASTE with parallel acquisition (PHASTE) decreases the number of echoes acquired and thus effectively reduces the blurring artifact caused by T2 relaxation. Further improvement in image sharpness can be achieved by performing T2 decay compensation before reconstructing the PHASTE data. Preliminary results have shown successful suppression of motion artifacts with PHASTE imaging. The image quality was enhanced relative to the original HASTE image, but was still less sharp than a non-motion-corrupted TSE image.

  17. Performance enhancement of MC-CDMA system through novel sensitive bit algorithm aided turbo multi user detection.

    PubMed

    Kumaravel, Rasadurai; Narayanaswamy, Kumaratharan

    2015-01-01

    Multi carrier code division multiple access (MC-CDMA) system is a promising multi carrier modulation (MCM) technique for high data rate wireless communication over frequency selective fading channels. MC-CDMA system is a combination of code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). The OFDM parts reduce multipath fading and inter symbol interference (ISI) and the CDMA part increases spectrum utilization. Advantages of this technique are its robustness in case of multipath propagation and improve security with the minimize ISI. Nevertheless, due to the loss of orthogonality at the receiver in a mobile environment, the multiple access interference (MAI) appears. The MAI is one of the factors that degrade the bit error rate (BER) performance of MC-CDMA system. The multiuser detection (MUD) and turbo coding are the two dominant techniques for enhancing the performance of the MC-CDMA systems in terms of BER as a solution of overcome to MAI effects. In this paper a low complexity iterative soft sensitive bits algorithm (SBA) aided logarithmic-Maximum a-Posteriori algorithm (Log MAP) based turbo MUD is proposed. Simulation results show that the proposed method provides better BER performance with low complexity decoding, by mitigating the detrimental effects of MAI. PMID:25714917

  18. Prospective Study of Plasmodium vivax Malaria Recurrence after Radical Treatment with a Chloroquine-Primaquine Standard Regimen in Turbo, Colombia.

    PubMed

    Zuluaga-Idárraga, Lina; Blair, Silvia; Akinyi Okoth, Sheila; Udhayakumar, Venkatachalam; Marcet, Paula L; Escalante, Ananias A; Alexander, Neal; Rojas, Carlos

    2016-08-01

    Plasmodium vivax recurrences help maintain malaria transmission. They are caused by recrudescence, reinfection, or relapse, which are not easily differentiated. A longitudinal observational study took place in Turbo municipality, Colombia. Participants with uncomplicated P. vivax infection received supervised treatment concomitantly with 25 mg/kg chloroquine and 0.25 mg/kg/day primaquine for 14 days. Incidence of recurrence was assessed over 180 days. Samples were genotyped, and origins of recurrences were established. A total of 134 participants were enrolled between February 2012 and July 2013, and 87 were followed for 180 days, during which 29 recurrences were detected. The cumulative incidence of first recurrence was 24.1% (21/87) (95% confidence interval [CI], 14.6 to 33.7%), and 86% (18/21) of these events occurred between days 51 and 110. High genetic diversity of P. vivax strains was found, and 12.5% (16/128) of the infections were polyclonal. Among detected recurrences, 93.1% (27/29) of strains were genotyped as genetically identical to the strain from the previous infection episode, and 65.5% (19/29) of infections were classified as relapses. Our results indicate that there is a high incidence of P. vivax malaria recurrence after treatment in Turbo municipality, Colombia, and that a large majority of these episodes are likely relapses from the previous infection. We attribute this to the primaquine regimen currently used in Colombia, which may be insufficient to eliminate hypnozoites. PMID:27185794

  19. Performance enhancement of MC-CDMA system through novel sensitive bit algorithm aided turbo multi user detection.

    PubMed

    Kumaravel, Rasadurai; Narayanaswamy, Kumaratharan

    2015-01-01

    Multi carrier code division multiple access (MC-CDMA) system is a promising multi carrier modulation (MCM) technique for high data rate wireless communication over frequency selective fading channels. MC-CDMA system is a combination of code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). The OFDM parts reduce multipath fading and inter symbol interference (ISI) and the CDMA part increases spectrum utilization. Advantages of this technique are its robustness in case of multipath propagation and improve security with the minimize ISI. Nevertheless, due to the loss of orthogonality at the receiver in a mobile environment, the multiple access interference (MAI) appears. The MAI is one of the factors that degrade the bit error rate (BER) performance of MC-CDMA system. The multiuser detection (MUD) and turbo coding are the two dominant techniques for enhancing the performance of the MC-CDMA systems in terms of BER as a solution of overcome to MAI effects. In this paper a low complexity iterative soft sensitive bits algorithm (SBA) aided logarithmic-Maximum a-Posteriori algorithm (Log MAP) based turbo MUD is proposed. Simulation results show that the proposed method provides better BER performance with low complexity decoding, by mitigating the detrimental effects of MAI.

  20. Performance Enhancement of MC-CDMA System through Novel Sensitive Bit Algorithm Aided Turbo Multi User Detection

    PubMed Central

    Kumaravel, Rasadurai; Narayanaswamy, Kumaratharan

    2015-01-01

    Multi carrier code division multiple access (MC-CDMA) system is a promising multi carrier modulation (MCM) technique for high data rate wireless communication over frequency selective fading channels. MC-CDMA system is a combination of code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). The OFDM parts reduce multipath fading and inter symbol interference (ISI) and the CDMA part increases spectrum utilization. Advantages of this technique are its robustness in case of multipath propagation and improve security with the minimize ISI. Nevertheless, due to the loss of orthogonality at the receiver in a mobile environment, the multiple access interference (MAI) appears. The MAI is one of the factors that degrade the bit error rate (BER) performance of MC-CDMA system. The multiuser detection (MUD) and turbo coding are the two dominant techniques for enhancing the performance of the MC-CDMA systems in terms of BER as a solution of overcome to MAI effects. In this paper a low complexity iterative soft sensitive bits algorithm (SBA) aided logarithmic-Maximum a-Posteriori algorithm (Log MAP) based turbo MUD is proposed. Simulation results show that the proposed method provides better BER performance with low complexity decoding, by mitigating the detrimental effects of MAI. PMID:25714917

  1. Multi-Echo Acquisition of O-Space Data

    PubMed Central

    Galiana, Gigi; Peters, Dana; Tam, Leo; Constable, R. Todd

    2014-01-01

    Purpose Nonlinear gradient encoding methods, such as O-Space imaging, have been shown to provide good images from very few echoes. Acquiring data in a train of spin or gradient echoes is a very flexible way to further speed acquisition time. However, combining these strategies presents significant challenges, both in terms of the contrast and artifacts. We present strategies in both pulse sequence design and image processing to mitigate these effects. Theory and Methods The three strategies include a new echo ordering that takes into account the unique way that O-Space samples the k-space of the image; a new post-processing filter that allows tuning of T2-weighting by emphasizing the contribution of low frequency spatial information at selectable points in space and time; and an offset between linear and nonlinear gradients that makes the central point of each echo unique. Results Simulations indicate that these strategies mitigate artifacts introduced by T2 (or T2*) decay and produce contrast that reflects relaxation at a given TE. Conclusion Turbo spin echo O-Space is theoretically feasible, and the greater undersampling should make it possible to use shorter echo trains for a given scan time. PMID:24459076

  2. Assessment of error propagation in ultraspectral sounder data via JPEG2000 compression and turbo coding

    NASA Astrophysics Data System (ADS)

    Olsen, Donald P.; Wang, Charles C.; Sklar, Dean; Huang, Bormin; Ahuja, Alok

    2005-08-01

    Research has been undertaken to examine the robustness of JPEG2000 when corrupted by transmission bit errors in a satellite data stream. Contemporary and future ultraspectral sounders such as Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder (CrIS), Infrared Atmospheric Sounding Interferometer (IASI), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and Hyperspectral Environmental Suite (HES) generate a large volume of three-dimensional data. Hence, compression of ultraspectral sounder data will facilitate data transmission and archiving. There is a need for lossless or near-lossless compression of ultraspectral sounder data to avoid potential retrieval degradation of geophysical parameters due to lossy compression. This paper investigates the simulated error propagation in AIRS ultraspectral sounder data with advanced source and channel coding in a satellite data stream. The source coding is done via JPEG2000, the latest International Organization for Standardization (ISO)/International Telecommunication Union (ITU) standard for image compression. After JPEG2000 compression the AIRS ultraspectral sounder data is then error correction encoded using a rate 0.954 turbo product code (TPC) for channel error control. Experimental results of error patterns on both channel and source decoding are presented. The error propagation effects are curbed via the block-based protection mechanism in the JPEG2000 codec as well as memory characteristics of the forward error correction (FEC) scheme to contain decoding errors within received blocks. A single nonheader bit error in a source code block tends to contaminate the bits until the end of the source code block before the inverse discrete wavelet transform (IDWT), and those erroneous bits propagate even further after the IDWT. Furthermore, a single header bit error may result in the corruption of almost the entire decompressed granule. JPEG2000 appears vulnerable to bit errors in a noisy channel of

  3. Multi-echo acquisition

    PubMed Central

    Posse, Stefan

    2011-01-01

    The rapid development of fMRI was paralleled early on by the adaptation of MR spectroscopic imaging (MRSI) methods to quantify water relaxation changes during brain activation. This review describes the evolution of multi-echo acquisition from high-speed MRSI to multi-echo EPI and beyond. It highlights milestones in the development of multi-echo acquisition methods, such as the discovery of considerable gains in fMRI sensitivity when combining echo images, advances in quantification of the BOLD effect using analytical biophysical modeling and interleaved multi-region shimming. The review conveys the insight gained from combining fMRI and MRSI methods and concludes with recent trends in ultra-fast fMRI, which will significantly increase temporal resolution of multi-echo acquisition. PMID:22056458

  4. Resolution enhanced T1-insensitive steady-state imaging.

    PubMed

    Derakhshan, Jamal J; Nour, Sherif G; Sunshine, Jeffrey L; Griswold, Mark A; Duerk, Jeffrey L

    2012-08-01

    Resolution enhanced T(1)-insensitive steady-state imaging (RE-TOSSI) is a new MRI pulse sequence for the generation of rapid T(2) contrast with high spatial resolution. TOSSI provides T(2) contrast by using nonequally spaced inversion pulses throughout a balanced steady-state free precession (SSFP) acquisition. In RE-TOSSI, these energy and time intensive adiabatic inversion pulses and associated magnetization preparation are removed from TOSSI after acquisition of the data around the center of k-space. Magnetization evolution simulations demonstrate T(2) contrast in TOSSI as well as reduction in the widening of the point spread function width (by up to a factor of 4) to a near ideal case for RE-TOSSI. Phantom experimentation is used to characterize and compare the contrast and spatial resolution properties of TOSSI, RE-TOSSI, balanced SSFP, Half-Fourier Acquisition Single-Shot Turbo Spin Echo (HASTE), and turbo spin echo and to optimize the fraction of k-space acquired using TOSSI. Comparison images in the abdomen and brain demonstrate similar contrast and improved spatial resolution in RE-TOSSI compared with TOSSI; comparison balanced SSFP, HASTE, and turbo spin echo images are provided. RE-TOSSI is capable of providing high spatial resolution T(2)-weighted images in 1 s or less per image.

  5. Merger and acquisition medicine.

    PubMed

    Powell, G S

    1997-01-01

    This discussion of the ramifications of corporate mergers and acquisitions for employees recognizes that employee adaptation to the change can be a long and complex process. The author describes a role the occupational physician can take in helping to minimize the potential adverse health impact of major organizational change.

  6. Acquisitions List No. 42.

    ERIC Educational Resources Information Center

    Planned Parenthood--World Population, New York, NY. Katherine Dexter McCormick Library.

    The "Acquisitions List" of demographic books and articles is issued every two months by the Katharine Dexter McCormick Library. Divided into two parts, the first contains a list of books most recently acquired by the Library, each one annotated and also marked with the Library call number. The second part consists of a list of annotated articles,…

  7. Acquisitions List No. 43.

    ERIC Educational Resources Information Center

    Planned Parenthood--World Population, New York, NY. Katherine Dexter McCormick Library.

    The "Acquisitions List" of demographic books and articles is issued every two months by the Katharine Dexter McCormick Library. Divided into two parts, the first contains a list of books most recently acquired by the Library, each one annotated and also marked with the Library call number. The second part consists of a list of annotated articles,…

  8. First Language Acquisition.

    ERIC Educational Resources Information Center

    Clark, Eve V.

    This book examines children's acquisition of a first language, the stages they go through, and how they use language as they learn. There are 16 chapters in 4 parts. After chapter 1, "Acquiring Languages: Issues and Questions," Part 1, "Getting Started," offers (2) "In Conversation with Children," (3) "Starting on Language: Perception," (4) "Early…

  9. Telecommunications and data acquisition

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1981-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported. In addition, developments in Earth based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

  10. [Acquisition of arithmetic knowledge].

    PubMed

    Fayol, Michel

    2008-01-01

    The focus of this paper is on contemporary research on the number counting and arithmetical competencies that emerge during infancy, the preschool years, and the elementary school. I provide a brief overview of the evolution of children's conceptual knowledge of arithmetic knowledge, the acquisition and use of counting and how they solve simple arithmetic problems (e.g. 4 + 3). PMID:18198117

  11. Acquisition of Comparison Constructions

    ERIC Educational Resources Information Center

    Hohaus, Vera; Tiemann, Sonja; Beck, Sigrid

    2014-01-01

    This article presents a study on the time course of the acquisition of comparison constructions. The order in which comparison constructions (comparatives, measure phrases, superlatives, degree questions, etc.) show up in English- and German-learning children's spontaneous speech is quite fixed. It is shown to be insufficiently determined by…

  12. Data Acquisition Backend

    SciTech Connect

    Britton Jr., Charles L.; Ezell, N. Dianne Bull; Roberts, Michael

    2013-10-01

    This document is intended to summarize the development and testing of the data acquisition module portion of the Johnson Noise Thermometry (JNT) system developed at ORNL. The proposed system has been presented in an earlier report [1]. A more extensive project background including the project rationale is available in the initial project report [2].

  13. Image Acquisition Context

    PubMed Central

    Bidgood, W. Dean; Bray, Bruce; Brown, Nicolas; Mori, Angelo Rossi; Spackman, Kent A.; Golichowski, Alan; Jones, Robert H.; Korman, Louis; Dove, Brent; Hildebrand, Lloyd; Berg, Michael

    1999-01-01

    Objective: To support clinically relevant indexing of biomedical images and image-related information based on the attributes of image acquisition procedures and the judgments (observations) expressed by observers in the process of image interpretation. Design: The authors introduce the notion of “image acquisition context,” the set of attributes that describe image acquisition procedures, and present a standards-based strategy for utilizing the attributes of image acquisition context as indexing and retrieval keys for digital image libraries. Methods: The authors' indexing strategy is based on an interdependent message/terminology architecture that combines the Digital Imaging and Communication in Medicine (DICOM) standard, the SNOMED (Systematized Nomenclature of Human and Veterinary Medicine) vocabulary, and the SNOMED DICOM microglossary. The SNOMED DICOM microglossary provides context-dependent mapping of terminology to DICOM data elements. Results: The capability of embedding standard coded descriptors in DICOM image headers and image-interpretation reports improves the potential for selective retrieval of image-related information. This favorably affects information management in digital libraries. PMID:9925229

  14. Second Language Acquisition.

    ERIC Educational Resources Information Center

    McLaughlin, Barry; Harrington, Michael

    1989-01-01

    A distinction is drawn between representational and processing models of second-language acquisition. The first approach is derived primarily from linguistics, the second from psychology. Both fields, it is argued, need to collaborate more fully, overcoming disciplinary narrowness in order to achieve more fruitful research. (GLR)

  15. Coordinating Council. Seventh Meeting: Acquisitions

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The theme for this NASA Scientific and Technical Information Program Coordinating Council meeting was Acquisitions. In addition to NASA and the NASA Center for AeroSpace Information (CASI) presentations, the report contains fairly lengthy visuals about acquisitions at the Defense Technical Information Center. CASI's acquisitions program and CASI's proactive acquisitions activity were described. There was a presentation on the document evaluation process at CASI. A talk about open literature scope and coverage at the American Institute of Aeronautics and Astronautics was also given. An overview of the STI Program's Acquisitions Experts Committee was given next. Finally acquisitions initiatives of the NASA STI program were presented.

  16. 78 FR 37164 - Land Acquisitions: Appeals of Land Acquisition Decisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ... the full address. In proposed rule FR Doc. 2013-12708, published in the issue of May 29, 2013, make...; Docket ID: BIA-2013-0005] RIN 1076-AF15 Land Acquisitions: Appeals of Land Acquisition Decisions...

  17. 33. Perimeter acquisition radar building room #320, perimeter acquisition radar ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. Perimeter acquisition radar building room #320, perimeter acquisition radar operations center (PAROC), contains the tactical command and control group equipment required to control the par site. Showing spacetrack monitor console - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

  18. Feasibility study of air-breathing turbo-engines for horizontal take-off and landing space plane

    SciTech Connect

    Minoda, M.; Sakata, K.; Tamaki, T.; Saitoh, T.; Yasuda, A.

    1989-01-01

    Various concepts of air-breathing engines (ABEs) that could be used for a horizontal take-off and landing SSTO vehicle are investigated. The performances (with respect to thrust and the specific fuel consumption) of turboengines based on various technologies, including a turbojet with and without afterburner (TJ), turboramjet, and air-turbo-ram jet engines are compared. The mission capabilities of these ABEs for SSTO and TSTO vehicles is examined in terms of the ratio of the effective remaining weight (i.e., the weight on the orbit) to the take-off gross weight, using two-dimensional flight analysis. It was found that the dry TJ with the turbine inlet temperature 2000 C is one of the most promising candidates for the propulsion system of the SSTO vehicle, because of its small weight and high specific impulse. 6 refs.

  19. Fast nosological imaging using canonical correlation analysis of brain data obtained by two-dimensional turbo spectroscopic imaging.

    PubMed

    Laudadio, Teresa; Martínez-Bisbal, M Carmen; Celda, Bernardo; Van Huffel, Sabine

    2008-05-01

    A new fast and accurate tissue typing technique has recently been successfully applied to prostate MR spectroscopic imaging (MRSI) data. This technique is based on canonical correlation analysis (CCA), a statistical method able to simultaneously exploit the spectral and spatial information characterizing the MRSI data. Here, the performance of CCA is further investigated by using brain data obtained by two-dimensional turbo spectroscopic imaging (2DTSI) from patients affected by glioblastoma. The purpose of this study is to investigate the applicability of CCA when typing tissues of heterogeneous tumors. The performance of CCA is also compared with that of ordinary correlation analysis on simulated as well as in vivo data. The results show that CCA outperforms ordinary correlation analysis in terms of robustness and accuracy.

  20. A study of the effects of disk flexibility on the rotordynamics of the space shuttle main engine turbo-pumps

    NASA Technical Reports Server (NTRS)

    Flowers, George T.

    1989-01-01

    Rotor dynamical analyses are typically performed using rigid disk models. Studies of rotor models in which the effects of disk flexibility were included indicate that is may be an important effect for many systems. This issue is addressed with respect to the Space Shuttle Main Engine high pressure turbo-pumps. Finite element analyses have been performed for a simplified free-free flexible disk rotor model and the modes and frequencies compared to those of a rigid disk model. The simple model was then extended to a more sophisticated HPTOP rotor model and similar results were observed. Equations were developed that are suitable for modifying the current rotordynamical analysis program to account for disk flexibility. Some conclusions are drawn from the results of this work as to the importance of disk flexibility on the HPTOP rotordynamics and some recommendations are given for follow-up research in this area.

  1. [A case of food-dependent-exercise induced anaphylaxis possibly induced by shellfish (Sulculus Supertexta and Turbo Cornutus)].

    PubMed

    Juji, F; Takashima, H; Suko, M; Doi, M; Takaishi, T; Okudaira, H; Ito, K; Miyamoto, T

    1990-11-01

    A 17 years old girl experienced an anaphylactic reaction of urticaria, dyspnea, syncope and hypotension while riding a bicycle 55 minutes after eating shellfish Lapas shellfish which was a-like Sulculus Supertexta (SS). She recovered within several hours after the emergency treatment. Another attack occurred 3 months later while she was running with a dog 30 minutes after eating shellfish (Turbo Cornutus; TC). RAST scores were 4 for Lapas and 2 for TC. RAST inhibition test by ELISA showed a high crose-reaction between keyhole limpet hemocyanin (KLH) and Lapas, and between KLH and TC, while the cross reaction between Lapas and TC was low. Gel chromatography with sephacryl G-200 revealed that both Lapas and TC had several allergens with different molecules which were detected by ELISA. Exercise challenge produced an immediate fall of FEV1 and a significant increase in plasma histamine levels for 45 minutes.

  2. A Lagrangian parcel based mixing plane method for calculating water based mixed phase particle flows in turbo-machinery

    NASA Astrophysics Data System (ADS)

    Bidwell, Colin S.

    2015-05-01

    A method for calculating particle transport through turbo-machinery using the mixing plane analogy was developed and used to analyze the energy efficient engine . This method allows the prediction of temperature and phase change of water based particles along their path and the impingement efficiency and particle impact property data on various components in the engine. This methodology was incorporated into the LEWICE3D V3.5 software. The method was used to predict particle transport in the low pressure compressor of the . The was developed by NASA and GE in the early 1980s as a technology demonstrator and is representative of a modern high bypass turbofan engine. The flow field was calculated using the NASA Glenn ADPAC turbo-machinery flow solver. Computations were performed for a Mach 0.8 cruise condition at 11,887 m assuming a standard warm day for ice particle sizes of 5, 20 and 100 microns and a free stream particle concentration of . The impingement efficiency results showed that as particle size increased average impingement efficiencies and scoop factors increased for the various components. The particle analysis also showed that the amount of mass entering the inner core decreased with increased particle size because the larger particles were less able to negotiate the turn into the inner core due to particle inertia. The particle phase change analysis results showed that the larger particles warmed less as they were transported through the low pressure compressor. Only the smallest 5 micron particles were warmed enough to produce melting with a maximum average melting fraction of 0.18. The results also showed an appreciable amount of particle sublimation and evaporation for the 5 micron particles entering the engine core (22.6 %).

  3. Investigating potential light-duty efficiency improvements through simulation of turbo-compounding and waste-heat recovery systems

    SciTech Connect

    Edwards, Kevin Dean; Wagner, Robert M; Briggs, Thomas E

    2010-01-01

    Modern diesel engines used in light-duty transportation applications have peak brake thermal efficiencies in the range of 40-42% for high-load operation with substantially lower efficiencies at realistic road-load conditions. Thermodynamic energy and exergy analysis reveals that the largest losses from these engines are due to combustion irreversibility and heat loss to the coolant, through the exhaust, and by direct convection and radiation to the environment. Substantial improvement in overall engine efficiency requires reducing or recovering these losses. Unfortunately, much of the heat transfer either occurs at relatively low temperatures resulting in large entropy generation (such as in the air-charge cooler), is transferred to low-exergy flow streams (such as the oil and engine coolant), or is radiated or convected directly to the environment. While there are significant opportunities for recovery from the exhaust and EGR cooler for heavy-duty applications, achieving similar benefits for light-duty applications is complicated by transient, low-load operation at typical driving conditions and competition with the turbocharger and aftertreatment system for the limited thermal resources. We have developed an organic Rankine cycle model using GT-Suite to investigate the potential for efficiency improvement through waste-heat recovery from the exhaust and EGR cooler of a light-duty diesel engine. The model is used to examine the effects of efficiency-improvement strategies such as cylinder deactivation, use of advanced materials and improved insulation to limit ambient heat loss, and turbo-compounding on the steady-state performance of the ORC system and the availability of thermal energy for downstream aftertreatment systems. Results from transient drive-cycle simulations are also presented, and we discuss strategies to address operational difficulties associated with transient drive cycles and balancing the thermal requirements of waste-heat recovery

  4. Data acquisition instruments: Psychopharmacology

    SciTech Connect

    Hartley, D.S. III

    1998-01-01

    This report contains the results of a Direct Assistance Project performed by Lockheed Martin Energy Systems, Inc., for Dr. K. O. Jobson. The purpose of the project was to perform preliminary analysis of the data acquisition instruments used in the field of psychiatry, with the goal of identifying commonalities of data and strategies for handling and using the data in the most advantageous fashion. Data acquisition instruments from 12 sources were provided by Dr. Jobson. Several commonalities were identified and a potentially useful data strategy is reported here. Analysis of the information collected for utility in performing diagnoses is recommended. In addition, further work is recommended to refine the commonalities into a directly useful computer systems structure.

  5. Advanced Data Acquisition Systems

    NASA Technical Reports Server (NTRS)

    Perotti, J.

    2003-01-01

    Current and future requirements of the aerospace sensors and transducers field make it necessary for the design and development of new data acquisition devices and instrumentation systems. New designs are sought to incorporate self-health, self-calibrating, self-repair capabilities, allowing greater measurement reliability and extended calibration cycles. With the addition of power management schemes, state-of-the-art data acquisition systems allow data to be processed and presented to the users with increased efficiency and accuracy. The design architecture presented in this paper displays an innovative approach to data acquisition systems. The design incorporates: electronic health self-check, device/system self-calibration, electronics and function self-repair, failure detection and prediction, and power management (reduced power consumption). These requirements are driven by the aerospace industry need to reduce operations and maintenance costs, to accelerate processing time and to provide reliable hardware with minimum costs. The project's design architecture incorporates some commercially available components identified during the market research investigation like: Field Programmable Gate Arrays (FPGA) Programmable Analog Integrated Circuits (PAC IC) and Field Programmable Analog Arrays (FPAA); Digital Signal Processing (DSP) electronic/system control and investigation of specific characteristics found in technologies like: Electronic Component Mean Time Between Failure (MTBF); and Radiation Hardened Component Availability. There are three main sections discussed in the design architecture presented in this document. They are the following: (a) Analog Signal Module Section, (b) Digital Signal/Control Module Section and (c) Power Management Module Section. These sections are discussed in detail in the following pages. This approach to data acquisition systems has resulted in the assignment of patent rights to Kennedy Space Center under U.S. patent # 6

  6. Data Acquisition Systems

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Technology developed during a joint research program with Langley and Kinetic Systems Corporation led to Kinetic Systems' production of a high speed Computer Automated Measurement and Control (CAMAC) data acquisition system. The study, which involved the use of CAMAC equipment applied to flight simulation, significantly improved the company's technical capability and produced new applications. With Digital Equipment Corporation, Kinetic Systems is marketing the system to government and private companies for flight simulation, fusion research, turbine testing, steelmaking, etc.

  7. First Language Acquisition and Teaching

    ERIC Educational Resources Information Center

    Cruz-Ferreira, Madalena

    2011-01-01

    "First language acquisition" commonly means the acquisition of a single language in childhood, regardless of the number of languages in a child's natural environment. Language acquisition is variously viewed as predetermined, wondrous, a source of concern, and as developing through formal processes. "First language teaching" concerns schooling in…

  8. Complexity in language acquisition.

    PubMed

    Clark, Alexander; Lappin, Shalom

    2013-01-01

    Learning theory has frequently been applied to language acquisition, but discussion has largely focused on information theoretic problems-in particular on the absence of direct negative evidence. Such arguments typically neglect the probabilistic nature of cognition and learning in general. We argue first that these arguments, and analyses based on them, suffer from a major flaw: they systematically conflate the hypothesis class and the learnable concept class. As a result, they do not allow one to draw significant conclusions about the learner. Second, we claim that the real problem for language learning is the computational complexity of constructing a hypothesis from input data. Studying this problem allows for a more direct approach to the object of study--the language acquisition device-rather than the learnable class of languages, which is epiphenomenal and possibly hard to characterize. The learnability results informed by complexity studies are much more insightful. They strongly suggest that target grammars need to be objective, in the sense that the primitive elements of these grammars are based on objectively definable properties of the language itself. These considerations support the view that language acquisition proceeds primarily through data-driven learning of some form.

  9. Second language acquisition.

    PubMed

    Juffs, Alan

    2011-05-01

    Second language acquisition (SLA) is a field that investigates child and adult SLA from a variety of theoretical perspectives. This article provides a survey of some key areas of concern including formal generative theory and emergentist theory in the areas of morpho-syntax and phonology. The review details the theoretical stance of the two different approaches to the nature of language: generative linguistics and general cognitive approaches. Some results of key acquisition studies from the two theoretical frameworks are discussed. From a generative perspective, constraints on wh-movement, feature geometry and syllable structure, and morphological development are highlighted. From a general cognitive point of view, the emergence of tense and aspect marking from a prototype account of inherent lexical aspect is reviewed. Reference is made to general cognitive learning theories and to sociocultural theory. The article also reviews individual differences research, specifically debate on the critical period in adult language acquisition, motivation, and memory. Finally, the article discusses the relationship between SLA research and second language pedagogy. Suggestions for further reading from recent handbooks on SLA are provided. WIREs Cogni Sci 2011 2 277-286 DOI: 10.1002/wcs.106 For further resources related to this article, please visit the WIREs website.

  10. 75 FR 51416 - Defense Federal Acquisition Regulation Supplement; Acquisition of Commercial Items

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ... Defense Acquisition Regulations System 48 CFR Parts 202, 212, and 234 Defense Federal Acquisition Regulation Supplement; Acquisition of Commercial Items AGENCY: Defense Acquisition Regulations System... interim rule that amended the Defense Federal Acquisition Regulation Supplement (DFARS) to...

  11. Smart Acquisition EELS

    NASA Astrophysics Data System (ADS)

    Sader, K.; Schaffer, B.; Vaughan, G.; Wang, P.; Bleloch, A. L.; Brydson, R.; Brown, A.

    2010-07-01

    Electron energy loss (EEL) spectroscopy and high angle annular dark field (HAADF) imaging in aberration-corrected electron microscopes are powerful techniques to determine the chemical composition and structure of materials at atomic resolution. We have implemented Smart Acquisition, a flexible system of scanning transmission electron microsocpy (STEM) beam position control and EELS collection, on two aberration-corrected dedicated cold field emission gun (FEG) STEMs located at SuperSTEM, Daresbury Laboratory. This allows the collection of EEL spectra from spatially defined areas with a much lower electron dose possible than existing techniques such as spectrum imaging.

  12. Late Mitochondrial Acquisition, Really?

    PubMed Central

    Degli Esposti, Mauro

    2016-01-01

    This article provides a timely critique of a recent Nature paper by Pittis and Gabaldón that has suggested a late origin of mitochondria in eukaryote evolution. It shows that the inferred ancestry of many mitochondrial proteins has been incorrectly assigned by Pittis and Gabaldón to bacteria other than the aerobic proteobacteria from which the ancestor of mitochondria originates, thereby questioning the validity of their suggestion that mitochondrial acquisition may be a late event in eukaryote evolution. The analysis and approach presented here may guide future studies to resolve the true ancestry of mitochondria. PMID:27289097

  13. HYPERCP data acquisition system

    SciTech Connect

    Kaplan, D.M.; Luebke, W.R.; Chakravorty, A.

    1997-12-31

    For the HyperCP experiment at Fermilab, we have assembled a data acquisition system that records on up to 45 Exabyte 8505 tape drives in parallel at up to 17 MB/s. During the beam spill, data axe acquired from the front-end digitization systems at {approx} 60 MB/s via five parallel data paths. The front-end systems achieve typical readout deadtime of {approx} 1 {mu}s per event, allowing operation at 75-kHz trigger rate with {approx_lt}30% deadtime. Event building and tapewriting are handled by 15 Motorola MVME167 processors in 5 VME crates.

  14. Data acquisition system

    DOEpatents

    Phillips, David T.

    1979-01-01

    A data acquisition system capable of resolving transient pulses in the subnanosecond range. A pulse in an information carrying medium such as light is transmitted through means which disperse the pulse, such as a fiber optic light guide which time-stretches optical pulses by chromatic dispersion. This time-stretched pulse is used as a sampling pulse and is modulated by the signal to be recorded. The modulated pulse may be further time-stretched prior to being recorded. The recorded modulated pulse is unfolded to derive the transient signal by utilizing the relationship of the time-stretching that occurred in the original pulse.

  15. Acquisition-Management Program

    NASA Technical Reports Server (NTRS)

    Avery, Don E.; Vann, A. Vernon; Jones, Richard H.; Rew, William E.

    1987-01-01

    NASA Acquisition Management Subsystem (AMS) program integrated NASA-wide standard automated-procurement-system program developed in 1985. Designed to provide each NASA installation with procurement data-base concept with on-line terminals for managing, tracking, reporting, and controlling contractual actions and associated procurement data. Subsystem provides control, status, and reporting for various procurement areas. Purpose of standardization is to decrease costs of procurement and operation of automatic data processing; increases procurement productivity; furnishes accurate, on-line management information and improves customer support. Written in the ADABAS NATURAL.

  16. First language acquisition.

    PubMed

    Goodluck, Helen

    2011-01-01

    This article reviews current approaches to first language acquisition, arguing in favor of the theory that attributes to the child an innate knowledge of universal grammar. Such knowledge can accommodate the systematic nature of children's non-adult linguistic behaviors. The relationships between performance devices (mechanisms for comprehension and production of speech), non-linguistic aspects of cognition, and child grammars are also discussed. WIREs Cogn Sci 2011 2 47-54 DOI: 10.1002/wcs.95 For further resources related to this article, please visit the WIREs website.

  17. [Carotid plaque assessment using inversion recovery T1 weighted-3 dimensions variable refocus flip angle turbo spin echo sampling perfection with application optimized contrast using different angle evolutions black blood imaging].

    PubMed

    Inoue, Yuji; Yoneyama, Masami; Nakamura, Masanobu; Ozaki, Satoshi; Ito, Kenjiro; Hiura, Mikio

    2012-01-01

    Vulnerable plaque can be attributed to induction of ischemic symptoms and magnetic resonance imaging of carotid artery is valuable to detect the plaque. Magnetization prepared rapid acquisition with gradient echo (MPRAGE) method could detect hemorrhagic vulnerable plaque as high intensity signal; however, blood flow is not sufficiently masked by this method. The contrast for plaque in T1 weighted image (T1WI) could not be obtained sufficiently with black blood image (BBI) by sampling perfection with application optimized contrast using different angle evolutions (SPACE) method as turbo spin echo (TSE). In addition, an appearance of artifact by slow flow is a problem. Considering these controversial situations in plaque imaging, we examined the modified BBI inversion recovery (IR)-SPACE in which IR was added for SPACE method so that the contrast for plaque in T1WI was optimized. We investigated the application of this method in plaque imaging. As a result of phantom imaging, the contrast for plaque in T1WI was definitely obtained by choosing an appropriate inversion time (TI) for the corresponding repetition time. In clinical cases, blood flow was sufficiently masked by IR-SPACE method and the plaque imaging was clearly obtained in clinical cases to the same extent as MPRAGE method. Since BBI with IR-SPACE method was derived from both IR pulse and flow void effect, this method could obtain the blood flow masking effect definitely. The present study suggested that SPACE method might be applicable to estimate properties of carotid artery plaque.

  18. Assessment of left ventricular myocardial scar in infiltrative and non-ischemic cardiac diseases by free breathing three dimensional phase sensitive inversion recovery (PSIR) TurboFLASH.

    PubMed

    Kino, Aya; Keeling, Aoife N; Farrelly, Cormac T; Sheehan, John J; Davarpanah, Amir H; Weele, Peter J; Zuehldorff, Sven; Carr, James C

    2011-04-01

    The purpose of this study was to compare a navigator gated free breathing 3D Phase Sensitive Inversion Recovery (PSIR) TurboFLASH to an established 2D PSIR TurboFLASH method for detecting myocardial late gadolinium hyperenhanced lesions caused by infiltrative and non-ischemic cardiomyopathy. Under an IRB approved protocol; patients with suspected non-ischemic infiltrative myocardial heart disease were examined on a 1.5T MR scanner for late enhancement after the administration of gadolinium using a segmented 2D PSIR TurboFLASH sequence followed by a navigator-gated 3D PSIR TurboFLASH sequence. Two independent readers analyzed image quality using a four point Likert scale for qualitative analysis (0 = poor, non diagnostic; 1 = fair, diagnostic may be impaired; 2 = good, some artifacts but not interfering in diagnostics, 3 = excellent, no artifacts) and also reported presence or absence of scar. Detected scars were classified based on area and location and also compared quantitatively in volume. Twenty-seven patients were scanned using both protocols. Image quality score did not differ significantly (p = 0.358, Wilcoxon signed rank test) for both technique. Scars were detected in 24 patients. Larger numbers of hyperenhanced scars were detected with 3D PSIR (200) compared to 2D PSIR (167) and scar volume were significant larger in 3D PSIR (p = 0.004). The mean scar volume over all cases was 49.95 cm(3) for 2D PSIR and 70.02 cm(3) for 3D PSIR. The navigator gated free breathing 3D PSIR approach is a suitable method for detecting myocardial late gadolinium hyperenhanced lesions caused by non-ischemic cardiomyopathy due to its complete isotropic coverage of the left ventricle, improving detection of scar lesions compared to 2D PSIR imaging.

  19. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  20. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  1. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  2. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  3. 48 CFR 1034.004 - Acquisition strategy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... “lock in”. (b) The acquisition strategy shall be approved by a chartered interdisciplinary acquisition... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Acquisition strategy. 1034... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 1034.004 Acquisition strategy. (a) A...

  4. 48 CFR 1034.004 - Acquisition strategy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... “lock in”. (b) The acquisition strategy shall be approved by a chartered interdisciplinary acquisition... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Acquisition strategy. 1034... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 1034.004 Acquisition strategy. (a) A...

  5. Data-acquisition systems

    SciTech Connect

    Cyborski, D.R.; Teh, K.M.

    1995-08-01

    Up to now, DAPHNE, the data-acquisition system developed for ATLAS, was used routinely for experiments at ATLAS and the Dynamitron. More recently, the Division implemented 2 MSU/DAPHNE systems. The MSU/DAPHNE system is a hybrid data-acquisition system which combines the front-end of the Michigan State University (MSU) DA system with the traditional DAPHNE back-end. The MSU front-end is based on commercially available modules. This alleviates the problems encountered with the DAPHNE front-end which is based on custom designed electronics. The first MSU system was obtained for the APEX experiment and was used there successfully. A second MSU front-end, purchased as a backup for the APEX experiment, was installed as a fully-independent second MSU/DAPHNE system with the procurement of a DEC 3000 Alpha host computer, and was used successfully for data-taking in an experiment at ATLAS. Additional hardware for a third system was bought and will be installed. With the availability of 2 MSU/DAPHNE systems in addition to the existing APEX setup, it is planned that the existing DAPHNE front-end will be decommissioned.

  6. Unsupervised Language Acquisition

    NASA Astrophysics Data System (ADS)

    de Marcken, Carl

    1996-11-01

    This thesis presents a computational theory of unsupervised language acquisition, precisely defining procedures for learning language from ordinary spoken or written utterances, with no explicit help from a teacher. The theory is based heavily on concepts borrowed from machine learning and statistical estimation. In particular, learning takes place by fitting a stochastic, generative model of language to the evidence. Much of the thesis is devoted to explaining conditions that must hold for this general learning strategy to arrive at linguistically desirable grammars. The thesis introduces a variety of technical innovations, among them a common representation for evidence and grammars, and a learning strategy that separates the ``content'' of linguistic parameters from their representation. Algorithms based on it suffer from few of the search problems that have plagued other computational approaches to language acquisition. The theory has been tested on problems of learning vocabularies and grammars from unsegmented text and continuous speech, and mappings between sound and representations of meaning. It performs extremely well on various objective criteria, acquiring knowledge that causes it to assign almost exactly the same structure to utterances as humans do. This work has application to data compression, language modeling, speech recognition, machine translation, information retrieval, and other tasks that rely on either structural or stochastic descriptions of language.

  7. Development of cooling system for 66/6.9kV-20MVA REBCO superconducting transformers with Ne turbo-Brayton refrigerator and subcooled liquid nitrogen

    NASA Astrophysics Data System (ADS)

    Iwakuma, M.; Adachi, K.; Yun, K.; Yoshida, K.; Sato, S.; Suzuki, Y.; Umeno, T.; Konno, M.; Hayashi, H.; Eguchi, T.; Izumi, T.; Shiohara, Y.

    2015-12-01

    We developed a turbo-Brayton refrigerator with Ne gas as a working fluid for a 3 ϕ- 66/6.9kV-2MVA superconducting transformer with coated conductors which was bath-cooled with subcooled LN2. The two-stage compressor and expansion turbine had non-contact magnetic bearings for a long maintenance interval. In the future, we intend to directly install a heat exchanger into the Glass-Fiber-Reinforced-Plastics cryostat of a transformer and make a heat exchange between the working fluid gas and subcooled LN2. In this paper we investigate the behaviour of subcooled LN2 in a test cryostat, in which heater coils were arranged side by side with a flat plate finned-tube heat exchanger. Here a He turbo-Brayton refrigerator was used as a substitute for a Ne turbo-Brayton one. The pressure at the surface of LN2 in the cryostat was one atmosphere. Just under the LN2 surface, a stationary layer of LN2 was created over the depth of 20 cm and temperature dropped from 77 K to 65 K with depth while, in the lower level than that, a natural convection flow of LN2 was formed and temperature was almost uniform over 1 m depth. The boundary plane between the stationary layer and the natural convection region was visible.

  8. SNAP: Simulating New Acquisition Processes

    NASA Technical Reports Server (NTRS)

    Alfeld, Louis E.

    1997-01-01

    Simulation models of acquisition processes range in scope from isolated applications to the 'Big Picture' captured by SNAP technology. SNAP integrates a family of models to portray the full scope of acquisition planning and management activities, including budgeting, scheduling, testing and risk analysis. SNAP replicates the dynamic management processes that underlie design, production and life-cycle support. SNAP provides the unique 'Big Picture' capability needed to simulate the entire acquisition process and explore the 'what-if' tradeoffs and consequences of alternative policies and decisions. Comparison of cost, schedule and performance tradeoffs help managers choose the lowest-risk, highest payoff at each step in the acquisition process.

  9. Plasmid acquisition in microgravity

    NASA Technical Reports Server (NTRS)

    Juergensmeyer, Margaret A.; Juergensmeyer, Elizabeth A.; Guikema, James A.

    1995-01-01

    In microgravity, bacteria often show an increased resistance to antibiotics. Bacteria can develop resistance to an antibiotic after transformation, the acquisition of DNA, usually in the form of a plasmid containing a gene for resistance to one or more antibiotics. In order to study the capacity of bacteria to become resistant to antibiotics in microgravity, we have modified the standard protocol for transformation of Escherichia coli for use in the NASA-flight-certified hardware package, The Fluid Processing Apparatus (FPA). Here we report on the ability of E. coli to remain competent for long periods of time at temperatures that are readily available on the Space Shuttle, and present some preliminary flight results.

  10. Silicon tracker data acquisition

    SciTech Connect

    Haynes, W.J.

    1997-12-31

    Large particle physics experiments are making increasing technological demands on the design and implementation of real-time data acquisition systems. The LHC will have bunch crossing intervals of 25 nanoseconds and detectors, such as CMS, will contain over 10 million electronic channels. Readout systems will need to cope with 100 kHz rates of 1 MByte-sized events. Over 70% of this voluminous flow will stem from silicon tracker and MSGC devices. This paper describes the techniques currently being harnessed from ASIC devices through to modular microprocessor-based architectures around standards such as VMEbus and PCI. In particular, the experiences gained at the HERA H1 experiment are highlighted where many of the key technological concepts have already been im implemented.

  11. DSPS in data acquisition

    SciTech Connect

    Kirsch, M.; Haeupke, T.; Oelschlaeger, R.; Struck, B.

    1997-12-31

    Off-the-shelf and customized DSP boards in different bus architectures are perfectly suited to act as building blocks for flexible and high performance data acquisition systems. Due to their architecture they can be used to enhance the performance of existing equipment as add ons, as state-of-the-art readout controllers, event builders, on-the-fly data formatters and higher level trigger processors. Applications covering the above mentioned fields with Motorolas 96002 HARC DSP in the DESY HERMES and H1 experiments, at the focal plane polarimeter at KVI and the NIST high flux neutron backscattering spectrometer will be presented. Future possibilities with VME, PCI and PMC boards based on Analog Devices SHARC DSP will be discussed. Systems on the base of Texas Instruments TMS320C6X promise to provide unprecedented performance.

  12. AIROscope stellar acquisition

    NASA Technical Reports Server (NTRS)

    Deboo, G. J.; Parra, G. T.; Hedlund, R. C.

    1974-01-01

    The acquisition system which operates in conjunction with a balloon-borne TV system, boresighted to a telescope is described. It has two main functions, a star field monitor and an offset star tracker. The design of the system was strongly influenced by the TV camera, which uses the same interlaced scanning system as is employed in commercial television broadcasting. To reduce power and bandwidth requirements, the star field information transmitted in our system consists only of the horizontal and vertical coordinates of each star and its brightness. As a star field monitor the system provides video thresholding, camera blemish suppression, coordinate digitization in 3 axes, circuity to recognize as single star the dispersed video signals resulting from one star overlapping adjacent scanning lines and storage of all signals for readout by the telemetry at appropriate times.

  13. Theories of language acquisition.

    PubMed

    Vetter, H J; Howell, R W

    1971-03-01

    Prior to the advent of generative grammar, theoretical approaches to language development relied heavily upon the concepts ofdifferential reinforcement andimitation. Current studies of linguistic acquisition are largely dominated by the hypothesis that the child constructs his language on the basis of a primitive grammar which gradually evolves into a more complex grammar. This approach presupposes that the investigator does not impose his own grammatical rules on the utterances of the child; that the sound system of the child and the rules he employs to form sentences are to be described in their own terms, independently of the model provided by the adult linguistic community; and that there is a series of steps or stages through which the child passes on his way toward mastery of the adult grammar in his linguistic environment. This paper attempts to trace the development of human vocalization through prelinguistic stages to the development of what can be clearly recognized as language behavior, and then progresses to transitional phases in which the language of the child begins to approximate that of the adult model. In the view of the authors, the most challenging problems which confront theories of linguistic acquisition arise in seeking to account for structure of sound sequences, in the rules that enable the speaker to go from meaning to sound and which enable the listener to go from sound to meaning. The principal area of concern for the investigator, according to the authors, is the discovery of those rules at various stages of the learning process. The paper concludes with a return to the question of what constitutes an adequate theory of language ontogenesis. It is suggested that such a theory will have to be keyed to theories of cognitive development and will have to include and go beyond a theory which accounts for adult language competence and performance, since these represent only the terminal stage of linguistic ontogenesis.

  14. 78 FR 49990 - Land Acquisitions: Appeals of Land Acquisition Decisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ...: Comments on the proposed rule published May 29, 2013 (78 FR 32214) must be received by September 3, 2013... 25 CFR 151.12 (78 FR 32214). The proposed rule would remove procedural requirements that are no...; Docket ID: BIA-2013-0005] RIN 1076-AF15 Land Acquisitions: Appeals of Land Acquisition Decisions...

  15. Lexical Acquisition and Acquisition of Initial Voiceless Stops.

    ERIC Educational Resources Information Center

    Tyler, Ann A.; Edwards, Mary Louise

    1993-01-01

    Interaction between lexical acquisition and acquisition of initial voiceless stops (VSs) was studied in two normally developing children by acoustically examining token-by-token accuracy of initial VS targets in different lexical items. Tokens representing the emergence of accurate VS production were restricted to certain words, largely old words…

  16. Single-shot tomographic movies of evolving light-velocity objects

    PubMed Central

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Chang, Yen-Yu; Downer, Michael C.

    2014-01-01

    Tomography—cross-sectional imaging based on measuring radiation transmitted through an object along different directions—enables non-invasive imaging of hidden stationary objects, such as internal bodily organs, from their sequentially measured projections. Here we adapt tomographic methods to visualize—in one laser shot—the instantaneous structure and evolution of a laser-induced object propagating through a transparent Kerr medium. We reconstruct ‘movies’ of a laser pulse’s diffraction, self-focusing and filamentation from phase ‘streaks’ imprinted onto probe pulses that cross the main pulse’s path simultaneously at different angles. Multiple probes are generated and detected compactly and simply, making the system robust, easy to align and adaptable to many problems. Our technique could potentially visualize, for example, plasma wakefield accelerators, optical rogue waves or fast ignitor pulses, light-velocity objects, whose detailed space–time dynamics are known only through intensive computer simulations. PMID:24448430

  17. Coherence-assisted single-shot cooling by quantum absorption refrigerators

    NASA Astrophysics Data System (ADS)

    Mitchison, Mark T.; Woods, Mischa P.; Prior, Javier; Huber, Marcus

    2015-11-01

    The extension of thermodynamics into the quantum regime has received much attention in recent years. A primary objective of current research is to find thermodynamic tasks which can be enhanced by quantum mechanical effects. With this goal in mind, we explore the finite-time dynamics of absorption refrigerators composed of three quantum bits (qubits). The aim of this finite-time cooling is to reach low temperatures as fast as possible and subsequently extract the cold particle to exploit it for information processing purposes. We show that the coherent oscillations inherent to quantum dynamics can be harnessed to reach temperatures that are colder than the steady state in orders of magnitude less time, thereby providing a fast source of low-entropy qubits. This effect demonstrates that quantum thermal machines can surpass classical ones, reminiscent of quantum advantages in other fields, and is applicable to a broad range of technologically important scenarios.

  18. Single shot three-dimensional imaging using an engineered point spread function.

    PubMed

    Berlich, René; Bräuer, Andreas; Stallinga, Sjoerd

    2016-03-21

    A system approach to acquire a three-dimensional object distribution is presented using a compact and cost efficient camera system with an engineered point spread function. The corresponding monocular setup incorporates a phase-only computer-generated hologram in combination with a conventional imaging objective in order to optically encode the axial information within a single two-dimensional image. The object's depth map is calculated using a novel approach based on the power cepstrum of the image. The in-plane RGB image information is restored with an extended depth of focus by applying an adapted Wiener filter. The presented approach is tested experimentally by estimating the three-dimensional distribution of an extended passively illuminated scene. PMID:27136790

  19. Symmetrical Josephson vortex interferometer as an advanced ballistic single-shot detector

    SciTech Connect

    Soloviev, I. I.; Klenov, N. V.; Bakurskiy, S. V.; Pankratov, A. L.; Kuzmin, L. S.

    2014-11-17

    We consider a ballistic detector formed in an interferometer manner which operational principle relies on Josephson vortex scattering at a measurement potential. We propose an approach to symmetrize the detector scheme and explore arising advantages in the signal-to-noise ratio and in the back-action on a measured object by means of recently presented numerical and analytical methods for modeling of a soliton scattering dynamics in the presence of thermal fluctuations. The obtained characteristics for experimentally relevant parameters reveal practical applicability of the considered schemes including possibility of coupling with standard digital rapid single flux quantum circuits.

  20. High-fidelity single-shot three-qubit gates via machine learning

    NASA Astrophysics Data System (ADS)

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C.

    Three-qubit quantum gates play a crucial role in quantum error correction and quantum information processing. Here I discuss how to generate policies for quantum control to design three-qubit gates namely, Toffoli, Controlled-Not-Not and Fredkin gates for an architecture of nearest-neighbor-coupled superconducting artificial atoms. The resulted fidelity for each gate is above the 99.9% which is the threshold fidelity for fault-tolerant quantum computing. We test our policy in the presence of decoherence-induced noise as well as show its robustness under random external noise. The three-qubit gates are designed via our machine learning algorithm called Subspace-Selective Self-Adaptive Differential Evolution (SuSSADE). NSERC, AITF and University of Calgarys Eyes High Fellowship Program.

  1. Comparison of scintillators for single shot imaging of laser accelerated proton beams

    NASA Astrophysics Data System (ADS)

    Cook, Nathan

    2012-03-01

    The application of intense laser pulses incident on specialized targets provides exciting new means for generating energetic beams of protons and ions. Recent work has demonstrated the utility of these beams of particles in a variety of applications, from inertial confinement fusion to radiation therapy. These applications require precise control, and subsequently precise feedback from the beam. Imaging techniques can provide the necessary shot-to-shot characterization to be effective as diagnostics. However, the utility of imaging methods scales with the capability of scintillating materials to emit well characterized and consistent radiation upon irradiance by a charged particle beam. We will discuss three candidates for an ideal diagnostic for MeV range protons and light ions. CsI:Tl^+ and Al2O3:Cr^3+ are two inorganic scintillators which exhibit excellent response to hadrons in this energy range. They are compared with the combination diagnostic micro-channel plate with a P43 phosphor screen, which offers advantages in refresh rate and resolution over direct exposure methods. Ultimately we will determine which candidate performs optimally as part of a robust, inexpensive diagnostic for laser accelerated protons and light ions.

  2. Parametric study on single shot peening by dimensional analysis method incorporated with finite element method

    NASA Astrophysics Data System (ADS)

    Wu, Xian-Qian; Wang, Xi; Wei, Yan-Peng; Song, Hong-Wei; Huang, Chen-Guang

    2012-06-01

    Shot peening is a widely used surface treatment method by generating compressive residual stress near the surface of metallic materials to increase fatigue life and resistance to corrosion fatigue, cracking, etc. Compressive residual stress and dent profile are important factors to evaluate the effectiveness of shot peening process. In this paper, the influence of dimensionless parameters on maximum compressive residual stress and maximum depth of the dent were investigated. Firstly, dimensionless relations of processing parameters that affect the maximum compressive residual stress and the maximum depth of the dent were deduced by dimensional analysis method. Secondly, the influence of each dimensionless parameter on dimensionless variables was investigated by the finite element method. Furthermore, related empirical formulas were given for each dimensionless parameter based on the simulation results. Finally, comparison was made and good agreement was found between the simulation results and the empirical formula, which shows that a useful approach is provided in this paper for analyzing the influence of each individual parameter.

  3. Single-shot titrations and reaction monitoring by slice-selective NMR spectroscopy.

    PubMed

    Niklas, T; Stalke, D; John, M

    2015-01-25

    A new method, based on slice-selective NMR spectroscopy of inhomogeneous mixtures, is introduced to perform NMR titrations and reaction monitoring in a single experiment. The method was applied to the titration of a lithium salt with 12-crown-4, and to the reaction of nBuLi with N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDTA).

  4. Single-shot X-ray phase-contrast imaging using two-dimensional gratings

    SciTech Connect

    Sato, Genta; Itoh, Hidenosuke; Nagai, Kentaro; Nakamura, Takashi; Yamaguchi, Kimiaki; Kondoh, Takeshi; Handa, Soichiro; Ouchi, Chidane; Teshima, Takayuki; Setomoto, Yutaka; Den, Toru

    2012-07-31

    We developed a two-dimensional gratings-based X-ray interferometer that requires only a single exposure for clinical radiography. The interferometer consisted of a checkerboard phase grating for {pi} phase modulation and a latticed amplitude grating. Using a synchrotron radiation source, the phase grating modulates the X-rays and generates a self-image, transformed to a moire fringe by the amplitude grating. To allow use of a conventional X-ray tube, the latticed source grating was installed downstream from the X-ray tube. Differential phase-contrast and scattering images in two orthogonal directions were obtained by Fourier analysis of the single moire fringe image and an absorption image. Results show that characteristic features of soft tissue in two orthogonal directions were clearly shown in the differential phase-contrast images.

  5. Single-shot measurements of the acoustic field of an electrohydraulic lithotripter using a hydrophone array

    PubMed Central

    Alibakhshi, Mohammad A.; Kracht, Jonathan M.; Cleveland, Robin O.; Filoux, Erwan; Ketterling, Jeffrey A.

    2013-01-01

    Piezopolymer-based hydrophone arrays consisting of 20 elements were fabricated and tested for use in measuring the acoustic field from a shock-wave lithotripter. The arrays were fabricated from piezopolymer films and were mounted in a housing to allow submersion into water. The motivation was to use the array to determine how the shot-to-shot variability of the spark discharge in an electrohydraulic lithotripter affects the resulting focused acoustic field. It was found that the dominant effect of shot-to-shot variability was to laterally shift the location of the focus by up to 5 mm from the nominal acoustic axis of the lithotripter. The effect was more pronounced when the spark discharge was initiated with higher voltages. The lateral beamwidth of individual, instantaneous shock waves were observed to range from 1.5 mm to 24 mm. Due to the spatial variation of the acoustic field, the average of instantaneous beamwidths were observed to be 1 to 2 mm narrower than beamwidths determined from traditional single-point measurements that average the pressure measured at each location before computing beamwidth. PMID:23654419

  6. UV-Vis as quantification tool for solubilized lignin following a single-shot steam process.

    PubMed

    Lee, Roland A; Bédard, Charles; Berberi, Véronique; Beauchet, Romain; Lavoie, Jean-Michel

    2013-09-01

    In this short communication, UV/Vis was used as an analytical tool for the quantification of lignin concentrations in aqueous mediums. A significant correlation was determined between absorbance and concentration of lignin in solution. For this study, lignin was produced from different types of biomasses (willow, aspen, softwood, canary grass and hemp) using steam processes. Quantification was performed at 212, 225, 237, 270, 280 and 287 nm. UV-Vis quantification of lignin was found suitable for different types of biomass making this a timesaving analytical system that could lead to uses as Process Analytical Tool (PAT) in biorefineries utilizing steam processes or comparable approaches.

  7. Single-shot calibration of soft x-ray mirrors using a sinusoidal transmission grating.

    PubMed

    Shpilman, Z; Ehrlich, Y; Maman, S; Levy, I; Shussman, T; Oren, G; Zakosky Nueberger, I; Hurvitz, G

    2014-11-01

    Calibration of soft x-ray diagnostics is a challenge due to the lack of laboratory-size calibrated sources. An in situ calibration method for newly developed x-ray mirrors, is presented. The x-ray source is produced by laser-matter interaction, and twin transmission gratings which create two identical dispersion lines. The gratings have a sinusoidal transmission function, which produces a highly precise high-orders free spectrum. An x-ray mirror interacts with one of the dispersion lines, and the mirror efficiency curve as a function of wavelength is extracted. Mirror efficiency shows good agreement with the literature, and evidence of water layer may justify the need of in situ calibration.

  8. Phase noise in pulsed Doppler lidar and limitations on achievable single-shot velocity accuracy

    NASA Technical Reports Server (NTRS)

    Mcnicholl, P.; Alejandro, S.

    1992-01-01

    The smaller sampling volumes afforded by Doppler lidars compared to radars allows for spatial resolutions at and below some sheer and turbulence wind structure scale sizes. This has brought new emphasis on achieving the optimum product of wind velocity and range resolutions. Several recent studies have considered the effects of amplitude noise, reduction algorithms, and possible hardware related signal artifacts on obtainable velocity accuracy. We discuss here the limitation on this accuracy resulting from the incoherent nature and finite temporal extent of backscatter from aerosols. For a lidar return from a hard (or slab) target, the phase of the intermediate frequency (IF) signal is random and the total return energy fluctuates from shot to shot due to speckle; however, the offset from the transmitted frequency is determinable with an accuracy subject only to instrumental effects and the signal to noise ratio (SNR), the noise being determined by the LO power in the shot noise limited regime. This is not the case for a return from a media extending over a range on the order of or greater than the spatial extent of the transmitted pulse, such as from atmospheric aerosols. In this case, the phase of the IF signal will exhibit a temporal random walk like behavior. It will be uncorrelated over times greater than the pulse duration as the transmitted pulse samples non-overlapping volumes of scattering centers. Frequency analysis of the IF signal in a window similar to the transmitted pulse envelope will therefore show shot-to-shot frequency deviations on the order of the inverse pulse duration reflecting the random phase rate variations. Like speckle, these deviations arise from the incoherent nature of the scattering process and diminish if the IF signal is averaged over times greater than a single range resolution cell (here the pulse duration). Apart from limiting the high SNR performance of a Doppler lidar, this shot-to-shot variance in velocity estimates has a practical impact on lidar design parameters. In high SNR operation, for example, a lidar's efficiency in obtaining mean wind measurements is determined by its repetition rate and not pulse energy or average power. In addition, this variance puts a practical limit on the shot-to-shot hard target performance required of a lidar.

  9. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    DOE PAGES

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; et al

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

  10. Single-shot speckle reduction in numerical reconstruction of digitally recorded holograms: comment.

    PubMed

    Maycock, Jonathan; Hennelly, Bryan; McDonald, John

    2015-09-01

    We comment on a recent Letter by Hincapie et al. [Opt. Lett.40, 1623 (2015)], in which the authors proposed a method to reduce the speckle noise in digital holograms. This method was previously published by us in Maycock ["Improving reconstructions of digital holograms," Ph.D. thesis (National University of Ireland, 2012)] and Maycock and Hennelly [Improving Reconstructions of Digital Holograms: Speckle Reduction and Occlusions in Digital Holography (Lambert Academic, 2014)]. We also wish to highlight an important limitation of the method resulting from the superposition of different perspectives of the object/scene, which was not addressed in their Letter. PMID:26368684

  11. A single-shot nanosecond neutron pulsed technique for the detection of fissile materials

    NASA Astrophysics Data System (ADS)

    Gribkov, V.; Miklaszewski, R. A.; Chernyshova, M.; Scholz, M.; Prokopovicz, R.; Tomaszewski, K.; Drozdowicz, K.; Wiacek, U.; Gabanska, B.; Dworak, D.; Pytel, K.; Zawadka, A.

    2012-07-01

    A novel technique with the potential of detecting hidden fissile materials is presented utilizing the interaction of a single powerful and nanosecond wide neutron pulse with matter. The experimental system is based on a Dense Plasma Focus (DPF) device as a neutron source generating pulses of almost mono-energetic 2.45 MeV and/or 14.0 MeV neutrons, a few nanoseconds in width. Fissile materials, consisting of heavy nuclei, are detected utilizing two signatures: firstly by measuring those secondary fission neutrons which are faster than the elastically scattered 2.45 MeV neutrons of the D-D reaction in the DPF; secondly by measuring the pulses of the slower secondary fission neutrons following the pulse of the fast 14 MeV neutrons from the D-T reaction. In both cases it is important to compare the measured spectrum of the fission neutrons induced by the 2.45 MeV or 14 MeV neutron pulse of the DPF with theoretical spectra obtained by mathematical simulation. Therefore, results of numerical modelling of the proposed system, using the MCNP5 and the FLUKA codes are presented and compared with experimental data.

  12. Single-shot betatron source size measurement from a laser-wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Köhler, A.; Couperus, J. P.; Zarini, O.; Jochmann, A.; Irman, A.; Schramm, U.

    2016-09-01

    Betatron radiation emitted by accelerated electrons in laser-wakefield accelerators can be used as a diagnostic tool to investigate electron dynamics during the acceleration process. We analyze the spectral characteristics of the emitted Betatron pattern utilizing a 2D x-ray imaging spectroscopy technique. Together with simultaneously recorded electron spectra and x-ray images, the betatron source size, thus the electron beam radius, can be deduced at every shot.

  13. Investigation of laser induced damage threshold measurement with single-shot on thin films

    NASA Astrophysics Data System (ADS)

    Liu, Zhichao; Zheng, Yi; Pan, Feng; Lin, Qi; Ma, Ping; Wang, Jian

    2016-09-01

    A method for rapid determination of laser induced damage threshold (LIDT) of optical coatings is proposed and investigated in this paper. By use of this method, the LIDT of thin film can be rapidly obtained by only one shot. The modulation of laser beam profile, which is considered as a negative factor in conventional LIDT test, is utilized in this method. Basing on image processing technique, the damage information could be extracted from the comparison between the damage pattern and beam intensity distribution in the test region. The applicability and repeatability of this testing method has been verified on three type reflectors, HfO2/SiO2, HfO2/Al2O3 and Ta2O5/SiO2. In addition, the experimental results showed that appropriate beam size, laser energy and image compression ratio are the key factors to ensure a high accuracy of LIDT.

  14. Single-Shot Smartphone-Based Quantitative Phase Imaging Using a Distorted Grating

    PubMed Central

    Yang, Zhenyu; Zhan, Qiwen

    2016-01-01

    Blood testing has been used as an essential tool to diagnose diseases for decades. Recently, there has been a rapid developing trend in using Quantitative Phase Imaging (QPI) methods for blood cell screening. Compared to traditional blood testing techniques, QPI has the advantage of avoiding dyeing or staining the specimen, which may cause damage to the cells. However, most existing systems are bulky and costly, requiring experienced personnel to operate. This work demonstrates the integration of one QPI method onto a smartphone platform and the application of imaging red blood cells. The adopted QPI method is based on solving the Intensity Transport Equation (ITE) from two de-focused pupil images taken in one shot by the smartphone camera. The device demonstrates a system resolution of about 1 μm, and is ready to be used for 3D morphological study of red blood cells. PMID:27441837

  15. Single-shot observation of optical rogue waves in integrable turbulence using time microscopy

    PubMed Central

    Suret, Pierre; Koussaifi, Rebecca El; Tikan, Alexey; Evain, Clément; Randoux, Stéphane; Szwaj, Christophe; Bielawski, Serge

    2016-01-01

    Optical fibres are favourable tabletop laboratories to investigate both coherent and incoherent nonlinear waves. In particular, exact solutions of the one-dimensional nonlinear Schrödinger equation such as fundamental solitons or solitons on finite background can be generated by launching periodic, specifically designed coherent waves in optical fibres. It is an open fundamental question to know whether these coherent structures can emerge from the nonlinear propagation of random waves. However the typical sub-picosecond timescale prevented—up to now—time-resolved observations of the awaited dynamics. Here, we report temporal ‘snapshots' of random light using a specially designed ‘time-microscope'. Ultrafast structures having peak powers much larger than the average optical power are generated from the propagation of partially coherent waves in optical fibre and are recorded with 250 femtoseconds resolution. Our experiment demonstrates the central role played by ‘breather-like' structures such as the Peregrine soliton in the emergence of heavy-tailed statistics in integrable turbulence. PMID:27713416

  16. A multi-frame soft x-ray pinhole imaging diagnostic for single-shot applications.

    PubMed

    Wurden, G A; Coffey, S K

    2012-10-01

    For high energy density magnetized target fusion experiments at the Air Force Research Laboratory FRCHX machine, obtaining multi-frame soft x-ray images of the field reversed configuration (FRC) plasma as it is being compressed will provide useful dynamics and symmetry information. However, vacuum hardware will be destroyed during the implosion. We have designed a simple in-vacuum pinhole nosecone attachment, fitting onto a Conflat window, coated with 3.2 mg∕cm(2) of P-47 phosphor, and covered with a thin 50-nm aluminum reflective overcoat, lens-coupled to a multi-frame Hadland Ultra intensified digital camera. We compare visible and soft x-ray axial images of translating (~200 eV) plasmas in the FRX-L and FRCHX machines in Los Alamos and Albuquerque.

  17. A multi-frame soft x-ray pinhole imaging diagnostic for single-shot applications

    SciTech Connect

    Wurden, G. A.; Coffey, S. K.

    2012-10-15

    For high energy density magnetized target fusion experiments at the Air Force Research Laboratory FRCHX machine, obtaining multi-frame soft x-ray images of the field reversed configuration (FRC) plasma as it is being compressed will provide useful dynamics and symmetry information. However, vacuum hardware will be destroyed during the implosion. We have designed a simple in-vacuum pinhole nosecone attachment, fitting onto a Conflat window, coated with 3.2 mg/cm{sup 2} of P-47 phosphor, and covered with a thin 50-nm aluminum reflective overcoat, lens-coupled to a multi-frame Hadland Ultra intensified digital camera. We compare visible and soft x-ray axial images of translating ({approx}200 eV) plasmas in the FRX-L and FRCHX machines in Los Alamos and Albuquerque.

  18. Reduction in ignition energy for single-shot microthrusters using pulsedlaser excitation

    NASA Astrophysics Data System (ADS)

    Hansen, William W.; Janson, Siegfried W.; Helvajian, Henry

    2002-09-01

    An experiment has been conducted to compare the ignition energy of an existing digital thruster design between a pulsed electrical and laser excitations. A 355nm Nd-YAG pulsed laser is used to ignite the stored lead styphnate propellant charge. Given the device design, roughly 800 μJ is necessary to ignite a 180 μg charge volume with a 90% probability of ignition. This energy value is considered an upper limit. Under equivalent conditions, roughly 2.4mJ of electrical energy is required to ignite the same volume. The digital thruster concept is one approach to provide a valveless, slap-on propulsion capability for small (1kg mass class) and large satellites (1000kg mass class) to help maintain attitude or control the damping of low frequency oscillations in extended surfaces.

  19. An audit of the haemodynamic and emergence characteristics of single-shot 'ketofol'.

    PubMed

    Grace, R F; Tang, D W; Namel, E

    2015-07-01

    'ketofol', the single-syringe combination of ketamine and propofol (50 mg of ketamine and 90 mg of propofol in a 10 ml syringe) is becoming increasingly popular for short procedures, progressively replacing the more traditional use of ketamine and diazepam in some settings. This audit examined the haemodynamic, emergence and other characteristics of ketofol administration in 42, otherwise fit, women undergoing bilateral post-partum tubal ligation at Vila Central Hospital in Vanuatu. The combination of ketamine and propofol had no clinically important adverse haemodynamic effects. Wake-up from ketofol was favourable, with low rates of nausea and minimal emergence delirium. However, 43% of patients required airway support. For short procedures such as post-partum tubal ligation in fit patients, ketofol appears to have minimal adverse haemodynamic effects and favourable emergence characteristics. PMID:26099764

  20. Single-shot observation of optical rogue waves in integrable turbulence using time microscopy

    NASA Astrophysics Data System (ADS)

    Suret, Pierre; Koussaifi, Rebecca El; Tikan, Alexey; Evain, Clément; Randoux, Stéphane; Szwaj, Christophe; Bielawski, Serge

    2016-10-01

    Optical fibres are favourable tabletop laboratories to investigate both coherent and incoherent nonlinear waves. In particular, exact solutions of the one-dimensional nonlinear Schrödinger equation such as fundamental solitons or solitons on finite background can be generated by launching periodic, specifically designed coherent waves in optical fibres. It is an open fundamental question to know whether these coherent structures can emerge from the nonlinear propagation of random waves. However the typical sub-picosecond timescale prevented--up to now--time-resolved observations of the awaited dynamics. Here, we report temporal `snapshots' of random light using a specially designed `time-microscope'. Ultrafast structures having peak powers much larger than the average optical power are generated from the propagation of partially coherent waves in optical fibre and are recorded with 250 femtoseconds resolution. Our experiment demonstrates the central role played by `breather-like' structures such as the Peregrine soliton in the emergence of heavy-tailed statistics in integrable turbulence.

  1. Single Shot Polarization Characterization of XUV FEL Pulses from Crossed Polarized Undulators

    PubMed Central

    Ferrari, E.; Allaria, E.; Buck, J.; De Ninno, G.; Diviacco, B.; Gauthier, D.; Giannessi, L.; Glaser, L.; Huang, Z.; Ilchen, M.; Lambert, G.; Lutman, A. A.; Mahieu, B.; Penco, G.; Spezzani, C.; Viefhaus, J.

    2015-01-01

    Polarization control is a key feature of light generated by short-wavelength free-electron lasers. In this work, we report the first experimental characterization of the polarization properties of an extreme ultraviolet high gain free-electron laser operated with crossed polarized undulators. We investigate the average degree of polarization and the shot-to-shot stability and we analyze aspects such as existing possibilities for controlling and switching the polarization state of the emitted light. The results are in agreement with predictions based on Gaussian beams propagation. PMID:26314764

  2. Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives

    SciTech Connect

    Whitley, Von H; Mcgrane, Shawn D; Moore, David S; Eakins, Dan E; Bolme, Cindy A

    2009-01-01

    We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, sample quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.

  3. Measuring the intensity and phase of two ultrashort pulses on a single shot

    SciTech Connect

    DeLong, K.W.; Trebino, R.

    1994-12-31

    The method of Frequency-Resolved Optical Gating (FROG) allows one to measure the amplitude and phase of an arbitrary femtosecond pulse on a single laser shot. An extension of this method, which they call Twin Recovery of Excitation E-fields using FROG (TREEFROG) allows one to measure two separate laser pulses. The two dissimilar pulses are used to generate a single ``TREEFROG trace`` from a simple experimental apparatus, and the two pulse electric fields are determined using a modified FROG pulse-retrieval algorithm.

  4. Single shot polarization characterization of XUV FEL pulses from crossed polarized undulators

    SciTech Connect

    Ferrari, E.; Allaria, E.; Buck, J.; De Ninno, G.; Diviacco, B.; Gauthier, D.; Giannessi, L.; Glaser, L.; Huang, Z.; Ilchen, M.; Lambert, G.; Lutman, A. A.; Mahieu, B.; Penco, G.; Spezzani, C.; Viefhaus, J.

    2015-08-28

    Polarization control is a key feature of light generated by short-wavelength free-electron lasers. In this work, we report the first experimental characterization of the polarization properties of an extreme ultraviolet high gain free-electron laser operated with crossed polarized undulators. We research the average degree of polarization and the shot-to-shot stability and we analyze aspects such as existing possibilities for controlling and switching the polarization state of the emitted light. The results are in agreement with predictions based on Gaussian beams propagation.

  5. Single-Shot Smartphone-Based Quantitative Phase Imaging Using a Distorted Grating.

    PubMed

    Yang, Zhenyu; Zhan, Qiwen

    2016-01-01

    Blood testing has been used as an essential tool to diagnose diseases for decades. Recently, there has been a rapid developing trend in using Quantitative Phase Imaging (QPI) methods for blood cell screening. Compared to traditional blood testing techniques, QPI has the advantage of avoiding dyeing or staining the specimen, which may cause damage to the cells. However, most existing systems are bulky and costly, requiring experienced personnel to operate. This work demonstrates the integration of one QPI method onto a smartphone platform and the application of imaging red blood cells. The adopted QPI method is based on solving the Intensity Transport Equation (ITE) from two de-focused pupil images taken in one shot by the smartphone camera. The device demonstrates a system resolution of about 1 μm, and is ready to be used for 3D morphological study of red blood cells.

  6. The chemical modification of the essential groups of beta-N-acetyl-D-glucosaminidase from Turbo cornutus Solander.

    PubMed

    Lin, Jian-Cheng; Chen, Qing-Xi; Shi, Yan; Li, Shao-Wei; Zhao, Hong

    2003-09-01

    The chemical modification of beta-N-acetyl-D-glucosaminidase (EC3.2.1.30) from Turbo cornutus Solander has been first studied. The results demonstrate that the sulfhydryl group of cysteine residues and the hydroxyl group of serine residues are not essential to the enzyme's function. The modification of indole group of tryptophan of the enzyme by N-bromosuccinimide (NBS) can lead to the complete inactivation, accompanying the absorption decreasing at 278 nm and the fluorescence intensity quenching at 335 nm, indicating that tryptophan is essential residue to the enzyme. The modification of amino group of lysine residue by formaldehyde and trinitrobenzenesulfonic acid also inactivates the enzyme completely. The results show that lysine and tryptophan are probably situated in the active site of the enzyme. The modification of the imidazole residue and carboxyl group leads to inactivate incompletely, indicating they are not the composing groups of the enzyme active center, and they are essential for maintaining the enzyme's conformation which is necessary for the catalytic activity of the enzyme.

  7. New online signature acquisition system

    NASA Astrophysics Data System (ADS)

    Oulefki, Adel; Mostefai, Messaoud; Abbadi, Belkacem; Djebrani, Samira; Bouziane, Abderraouf; Chahir, Youssef

    2013-01-01

    We present a nonconstraining and low-cost online signature acquisition system that has been developed to enhance the performances of an existing multimodal biometric authentication system (based initially on both voice and image modalities). A laboratory prototype has been developed and validated for an online signature acquisition.

  8. Language Acquisition, Pidgins and Creoles.

    ERIC Educational Resources Information Center

    Wode, Henning

    1981-01-01

    Suggests that structural universals between different-based pidgins result from universal linguo-cognitive processing strategies which are employed in learning languages. Some of the strategies occur in all types of acquisition, and others are more applicable to L2 type acquisition. Past research is discussed, and some exemplary data are given.…

  9. Handbook of Child Language Acquisition.

    ERIC Educational Resources Information Center

    Ritchie, William C., Ed.; Bhatia, Tej K., Ed.

    This volume provides a comprehensive overview of the major areas of research in the field of child language acquisition. It is divided into seven parts and 19 chapters. Part I is an introduction and overview. Part II covers central issues in the study of child language acquisition, focusing on syntax, including those of innateness, maturation, and…

  10. Knowledge Acquisition in Observational Astronomy.

    ERIC Educational Resources Information Center

    Vosniadou, Stella

    This paper presents findings from research on knowledge acquisition in observational astronomy to demonstrate the kinds of intuitive models children form and to show how these models influence the acquisition of science knowledge. Sixty children of approximate ages 6, 9, and 12 were given a questionnaire to investigate their knowledge of the size,…

  11. 48 CFR 304.7001 - Numbering acquisitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Numbering acquisitions. 304.7001 Section 304.7001 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATIVE MATTERS Acquisition Instrument Identification Numbering System 304.7001 Numbering acquisitions....

  12. 48 CFR 434.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Acquisition strategy. 434.004 Section 434.004 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 434.004 Acquisition strategy. (a) The...

  13. 48 CFR 1034.004 - Acquisition strategy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Acquisition strategy. 1034... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 1034.004 Acquisition strategy. (a) A program manager's acquisition strategy written at the system or investment level in accordance with FAR...

  14. 48 CFR 3034.004 - Acquisition strategy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Acquisition strategy. See (HSAR) 48 CFR 3009.570 for policy applicable to acquisition strategies that consider... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Acquisition strategy. 3034.004 Section 3034.004 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY,...

  15. 48 CFR 234.004 - Acquisition strategy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Acquisition strategy. 234..., DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION 234.004 Acquisition strategy. (1) See 209.570 for policy applicable to acquisition strategies that consider the use of lead...

  16. 48 CFR 234.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Acquisition strategy. 234..., DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION 234.004 Acquisition strategy. (1) See 209.570 for policy applicable to acquisition strategies that consider the use of lead...

  17. 48 CFR 34.004 - Acquisition strategy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Acquisition strategy. 34... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 34.004 Acquisition strategy. The program manager, as specified in agency procedures, shall develop an acquisition strategy tailored to the...

  18. 48 CFR 3034.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Acquisition strategy. See (HSAR) 48 CFR 3009.570 for policy applicable to acquisition strategies that consider... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Acquisition strategy. 3034.004 Section 3034.004 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY,...

  19. 48 CFR 34.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Acquisition strategy. 34... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 34.004 Acquisition strategy. The program manager, as specified in agency procedures, shall develop an acquisition strategy tailored to the...

  20. Ocean Data Acquisition System

    NASA Technical Reports Server (NTRS)

    Johnson, B.; Cavanaugh, J.; Smith, J.; Esaias, W.

    1988-01-01

    The Ocean Data Acquisition System (ODAS) is a low cost instrument with potential commercial application. It is easily mounted on a small aircraft and flown over the coastal zone ocean to remotely measure sea surface temperature and three channels of ocean color information. From this data, chlorophyll levels can be derived for use by ocean scientists, fisheries, and environmental offices. Data can be transmitted to shipboard for real-time use with sea truth measurements, ocean productivity estimates and fishing fleet direction. The aircraft portion of the system has two primary instruments: an IR radiometer to measure sea surface temperature and a three channel visible spectro-radiometer for 460, 490, and 520 nm wavelength measurements from which chlorophyll concentration can be derived. The aircraft package contains a LORAN-C unit for aircraft location information, clock, on-board data processor and formatter, digital data storage, packet radio terminal controller, and radio transceiver for data transmission to a ship. The shipboard package contains a transceiver, packet terminal controller, data processing and storage capability, and printer. Both raw data and chlorophyll concentrations are available for real-time analysis.