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Sample records for superimposed coherent fluxes

  1. Speed and the coherence of superimposed chromatic gratings.

    Science.gov (United States)

    Bosten, J M; Smith, L; Mollon, J D

    2016-05-01

    On the basis of measurements of the perceived coherence of superimposed drifting gratings, Krauskopf and Farell (1990) proposed that motion is analysed independently in different chromatic channels. They found that two gratings appeared to slip if each modulated one of the two 'cardinal' color mechanisms S/(L+M) and L/(L+M). If the gratings were defined along intermediate color directions, observers reported a plaid, moving coherently. We hypothesised that slippage might occur in chromatic gratings if the motion signal from the S/(L+M) channel is weak and equivalent to a lower speed. We asked observers to judge coherence in two conditions. In one, S/(L+M) and L/(L+M) gratings were physically the same speed. In the other, the two gratings had perceptually matched speeds. We found that the relative incoherence of cardinal gratings is the same whether gratings are physically or perceptually matched in speed. Thus our hypothesis was firmly contradicted. In a control condition, observers were asked to judge the coherence of stationary gratings. Interestingly, the difference in judged coherence between cardinal and intermediate gratings remained as strong as it was when the gratings moved. Our results suggest a possible alternative interpretation of Krauskopf and Farell's result: the processes of object segregation may precede the analysis of the motion of chromatic gratings, and the same grouping signals may prompt object segregation in the stationary and moving cases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Coherence properties in superconducting flux qubits

    Energy Technology Data Exchange (ETDEWEB)

    Spilla, Samuele

    2015-02-16

    The research work discussed in this thesis deals with the study of superconducting Josephson qubits. Superconducting qubits are solid-state artificial atoms which are based on lithographically defined Josephson tunnel junctions properties. When sufficiently cooled, these superconducting devices exhibit quantized states of charge, flux or junction phase depending on their design parameters. This allows to observe coherent evolutions of their states. The results presented can be divided into two parts. In a first part we investigate operations of superconducting qubits based on the quantum coherence in superconducting quantum interference devices (SQUID). We explain experimental data which has been observed in a SQUID subjected to fast, large-amplitude modifications of its effective potential shape. The motivations for this work come from the fact that in the past few years there have been attempts to interpret the supposed quantum behavior of physical systems, such as Josephson devices, within a classical framework. Moreover, we analyze the possibility of generating GHZ states, namely maximally entangled states, in a quantum system made out of three Josephson qubits. In particular, we investigate the possible limitations of the GHZ state generation due to coupling to bosonic baths. In the second part of the thesis we address a particular cause of decoherence of flux qubits which has been disregarded until now: thermal gradients, which can arise due to accidental non equilibrium quasiparticle distributions. The reason for these detrimental effects is that heat currents flowing through Josephson tunnel junctions in response to a temperature gradient are periodic functions of the phase difference between the electrodes. The phase dependence of the heat current comes from Andreev reflection, namely an interplay between the quasiparticles which carry heat and the superconducting condensate which is sensitive to the superconducting phase difference. Generally speaking

  3. Spectroscopy and coherent manipulation of single and coupled flux qubits

    International Nuclear Information System (INIS)

    Wu Yu-Lin; Deng Hui; Huang Ke-Qiang; Tian Ye; Yu Hai-Feng; Xue Guang-Ming; Jin Yi-Rong; Li Jie; Zhao Shi-Ping; Zheng Dong-Ning

    2013-01-01

    Measurements of three-junction flux qubits, both single flux qubits and coupled flux qubits, using a coupled direct current superconducting quantum interference device (dc-SQUID) for readout are reported. The measurement procedure is described in detail. We performed spectroscopy measurements and coherent manipulations of the qubit states on a single flux qubit, demonstrating quantum energy levels and Rabi oscillations, with Rabi oscillation decay time T Rabi = 78 ns and energy relaxation time T 1 = 315 ns. We found that the value of T Rabi depends strongly on the mutual inductance between the qubit and the magnetic coil. We also performed spectroscopy measurements on inductively coupled flux qubits. (general)

  4. [Superimposed lichen planus pigmentosus].

    Science.gov (United States)

    Monteagudo, Benigno; Suarez-Amor, Óscar; Cabanillas, Miguel; de Las Heras, Cristina; Álvarez, Juan Carlos

    2014-05-16

    Lichen planus pigmentosus is an uncommon variant of lichen planus that is characterized by the insidious onset of dark brown macules in sun-exposed areas and flexural folds. Superimposed linear lichen planus is an exceedingly rare disorder, but it has been found in both lichen planopilaris and lichen planus types. A 39-year-old woman is presented showing a segmental and linear lichen planus associated with non-segmental lesions meeting all criteria for the diagnosis of superimposed linear planus pigmentosus. The segmental lesions were always more pronounced.

  5. Synchrotron light science: from flux to brightness to coherence

    International Nuclear Information System (INIS)

    Margaritondo, G.

    1998-01-01

    One century after their discovery and first application to radiology, X-rays are finally achieving coherence. The potential impact on radiological imaging is extremely important, with significant social repercussions. These exciting developments are the final product of a revolution initiated in the late 1960's by Gianfranco Chiarotti and a few other pioneers, who first dreamed of using electron accelerators as superior X-rays sources, and then transformed this dream into reality

  6. Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography.

    Science.gov (United States)

    Lee, Jonghwan; Wu, Weicheng; Lesage, Frederic; Boas, David A

    2013-11-01

    As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor microvascular flow dynamics over many capillaries at different depths at the same time.

  7. Insufficiency of avoided crossings for witnessing large-scale quantum coherence in flux qubits

    Science.gov (United States)

    Fröwis, Florian; Yadin, Benjamin; Gisin, Nicolas

    2018-04-01

    Do experiments based on superconducting loops segmented with Josephson junctions (e.g., flux qubits) show macroscopic quantum behavior in the sense of Schrödinger's cat example? Various arguments based on microscopic and phenomenological models were recently adduced in this debate. We approach this problem by adapting (to flux qubits) the framework of large-scale quantum coherence, which was already successfully applied to spin ensembles and photonic systems. We show that contemporary experiments might show quantum coherence more than 100 times larger than experiments in the classical regime. However, we argue that the often-used demonstration of an avoided crossing in the energy spectrum is not sufficient to make a conclusion about the presence of large-scale quantum coherence. Alternative, rigorous witnesses are proposed.

  8. SUPERIMPOSED MESH PLOTTING IN MCNP

    Energy Technology Data Exchange (ETDEWEB)

    J. HENDRICKS

    2001-02-01

    The capability to plot superimposed meshes has been added to MCNP{trademark}. MCNP4C featured a superimposed mesh weight window generator which enabled users to set up geometries without having to subdivide geometric cells for variance reduction. The variance reduction was performed with weight windows on a rectangular or cylindrical mesh superimposed over the physical geometry. Experience with the new capability was favorable but also indicated that a number of enhancements would be very beneficial, particularly a means of visualizing the mesh and its values. The mathematics for plotting the mesh and its values is described here along with a description of other upgrades.

  9. Nerve Fiber Flux Analysis Using Wide-Field Swept-Source Optical Coherence Tomography.

    Science.gov (United States)

    Tan, Ou; Liu, Liang; Liu, Li; Huang, David

    2018-02-01

    To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT). Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions. There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory. Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans. NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.

  10. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    Science.gov (United States)

    Chesca, Boris; John, Daniel; Mellor, Christopher J.

    2015-10-01

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise SΦ1/2 decreases as 1/N1/2. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa2Cu3O7. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for SΦ1/2 between (0.25 and 0.44) μΦ0/Hz1/2 for temperatures in the range (77-83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10-17) mV and (0.3-2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  11. Infantile osteopetrosis with superimposed rickets.

    Science.gov (United States)

    Gonen, Korcan Aysun; Yazici, Zeynep; Gokalp, Gokhan; Ucar, Ayse Kalyoncu

    2013-01-01

    Rickets is a complication of infantile osteopetrosis and pre-treatment recognition of this complication is important. To describe four children with infantile osteopetrosis complicated by rickets (osteopetrorickets) and review the relevant literature. Retrospective chart analysis of four infants with osteopetrorickets and a systematic review of the relevant literature. We saw five children with infantile osteopetrosis, of whom four had superimposed rickets, for a period of 12 years. The review of the literature (including the current four children), yielded 20 children with infantile osteopetrorickets. The children ranged in age from 2 months to 12 months. In all children, hepatosplenomegaly was found. Sixteen (80%) children had visual impairments and eight (40%) children had hearing impairments. Serum calcium-phosphorus product was less than 30 in 18 children (90%). Twelve children (60%) were hypocalcemic and 18 (90%) were hypophosphatemic. In all children, the radiological examination demonstrated diffuse bony sclerosis and metaphyseal splaying and fraying of long bones. Five children (25%) had pathological fracture of extremities and 15 (75%) had rachitic rosary. Rickets as a complication to infantile osteopetrosis is not uncommon. Skeletal roentgenograms are of critical importance in the diagnosis of both osteopetrosis and superimposed rickets.

  12. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: Formation, structure, detachment and impact of flux change

    KAUST Repository

    Dreszer, C.; Wexler, Adam D.; Drusová , S.; Overdijk, T.; Zwijnenburg, Arie; Flemming, Hans Curt; Kruithof, Joop C.; Vrouwenvelder, Johannes S.

    2014-01-01

    Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s-1) and permeate flux (20 L m-2h-1).In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m-2h-1). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure.Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.

  13. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: Formation, structure, detachment and impact of flux change

    KAUST Repository

    Dreszer, C.

    2014-12-01

    Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s-1) and permeate flux (20 L m-2h-1).In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m-2h-1). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure.Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.

  14. Electrical stimulation superimposed onto voluntary muscular contraction.

    Science.gov (United States)

    Paillard, Thierry; Noé, Frédéric; Passelergue, Philippe; Dupui, Philippe

    2005-01-01

    Electrical stimulation (ES) reverses the order of recruitment of motor units (MU) observed with voluntary muscular contraction (VOL) since under ES, large MU are recruited before small MU. The superimposition of ES onto VOL (superimposed technique: application of an electrical stimulus during a voluntary muscle action) can theoretically activate more motor units than VOL performed alone, which can engender an increase of the contraction force. Two superimposed techniques can be used: (i) the twitch interpolation technique (ITT), which consists of interjecting an electrical stimulus onto the muscle nerve; and (ii) the percutaneous superimposed electrical stimulation technique (PST), where the stimulation is applied to the muscle belly. These two superimposed techniques can be used to evaluate the ability to fully activate a muscle. They can thus be employed to distinguish the central or peripheral nature of fatigue after exhausting exercise. In general, whatever the technique employed, the superimposition of ES onto volitional exercise does not recruit more MU than VOL, except with eccentric actions. Nevertheless, the neuromuscular response associated with the use of the superimposed technique (ITT and PST) depends on the parameter of the superimposed current. The sex and the training level of the subjects can also modify the physiological impact of the superimposed technique. Although the motor control differs drastically between training with ES and VOL, the integration of the superimposed technique in training programmes with healthy subjects does not reveal significant benefits compared with programmes performed only with voluntary exercises. Nevertheless, in a therapeutic context, training programmes using ES superimposition compensate volume and muscle strength deficit with more efficiency than programmes using VOL or ES separately.

  15. Progress toward coupled flux qubits with high connectivity and long coherence times

    Science.gov (United States)

    Weber, Steven; Hover, David; Rosenberg, Danna; Samach, Gabriel; Yoder, Jonilyn; Kerman, Andrew; Oliver, William

    The ability to engineer interactions between qubits is essential to all areas of quantum information science. The capability to tune qubit-qubit couplings in situ is desirable for gate-based quantum computing and analog quantum simulation and necessary for quantum annealing. Consequently, tunable coupling has been the subject of several experimental efforts using both transmon qubits and flux qubits. Recently, our group has demonstrated robust and long-lived capacitively shunted (C-shunt) flux qubits. Here, we discuss our efforts to develop architectures for tunably coupling these qubits. In particular, we focus on optimizing the RF SQUID coupler to achieve high connectivity. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) and by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  16. Controlled acceleration of superimposed Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2013-06-01

    Full Text Available spatial light modulator (SLM) to create superimposed, non-canonical, higher-order Bessel beams and a CCD camera to investigate the propagation of the resulting field. It is already known that the intensity profile of the resulting field experiences...

  17. Statistical properties of superimposed stationary spike trains.

    Science.gov (United States)

    Deger, Moritz; Helias, Moritz; Boucsein, Clemens; Rotter, Stefan

    2012-06-01

    The Poisson process is an often employed model for the activity of neuronal populations. It is known, though, that superpositions of realistic, non- Poisson spike trains are not in general Poisson processes, not even for large numbers of superimposed processes. Here we construct superimposed spike trains from intracellular in vivo recordings from rat neocortex neurons and compare their statistics to specific point process models. The constructed superimposed spike trains reveal strong deviations from the Poisson model. We find that superpositions of model spike trains that take the effective refractoriness of the neurons into account yield a much better description. A minimal model of this kind is the Poisson process with dead-time (PPD). For this process, and for superpositions thereof, we obtain analytical expressions for some second-order statistical quantities-like the count variability, inter-spike interval (ISI) variability and ISI correlations-and demonstrate the match with the in vivo data. We conclude that effective refractoriness is the key property that shapes the statistical properties of the superposition spike trains. We present new, efficient algorithms to generate superpositions of PPDs and of gamma processes that can be used to provide more realistic background input in simulations of networks of spiking neurons. Using these generators, we show in simulations that neurons which receive superimposed spike trains as input are highly sensitive for the statistical effects induced by neuronal refractoriness.

  18. Paroxysmal Nocturnal Hemoglobinuria Superimposed with Preeclampsia

    Directory of Open Access Journals (Sweden)

    Mann-Ling Chen

    2006-09-01

    Conclusion: The most frequent causes of PNH-related fetomaternal morbidity and mortality are hemolysis and thrombosis. The situation becomes even more complicated when PNH is superimposed with preeclampsia. Appropriate clinical surveillance, awareness of the potential risks of hemolysis and thrombosis, as well as evaluation of fetal wellbeing are essential.

  19. Tracking the evolution of a coherent magnetic flux rope continuously from the inner to the outer corona

    International Nuclear Information System (INIS)

    Cheng, X.; Ding, M. D.; Guo, Y.; Zhang, J.; Sun, J. Q.; Li, C.; Vourlidas, A.; Liu, Y. D.; Olmedo, O.

    2014-01-01

    The magnetic flux rope (MFR) is believed to be the underlying magnetic structure of coronal mass ejections (CMEs). However, it remains unclear how an MFR evolves into and forms the multi-component structure of a CME. In this paper, we perform a comprehensive study of an extreme-ultraviolet (EUV) MFR eruption on 2013 May 22 by tracking its morphological evolution, studying its kinematics, and quantifying its thermal property. As EUV brightenings begin, the MFR starts to rise slowly and shows helical threads winding around an axis. Meanwhile, cool filamentary materials descend spirally down to the chromosphere. These features provide direct observational evidence of intrinsically helical structure of the MFR. Through detailed kinematical analysis, we find that the MFR evolution has two distinct phases: a slow rise phase and an impulsive acceleration phase. We attribute the first phase to the magnetic reconnection within the quasi-separatrix layers surrounding the MFR, and the much more energetic second phase to the fast magnetic reconnection underneath the MFR. We suggest that the transition between these two phases is caused by the torus instability. Moreover, we identify that the MFR evolves smoothly into the outer corona and appears as a coherent structure within the white-light CME volume. The MFR in the outer corona was enveloped by bright fronts that originated from plasma pile-up in front of the expanding MFR. The fronts are also associated with the preceding sheath region followed by the outmost MFR-driven shock.

  20. [Electroencephalography in delirium superimposed on dementia].

    Science.gov (United States)

    Hanemaaijer, Judith I; Wijnen, Viona J M; van Gool, W A

    2017-09-01

    Recognizing delirium superimposed on pre-existing cognitive impairment or dementia, 'delirium superimposed on dementia' (DSD), is challenging because signs of delirium might be interpreted as symptoms of pre-existing cognitive dysfunction.In this paper, we review the literature on the role of electrencephalography (EEG) in the differential diagnosis of delirium, dementia and DSD.Conventional EEG, applying twenty to thirty electrodes, taking thirty minutes registration, is not feasible in psychogeriatric patients. Recent studies suggest that it is possible to reliably detect delirium using only a limited number of EEG electrodes for a short period of time.With this, use of EEG in the detection of delirium in patients with cognitive impairment or clinically manifest dementia could be possible.

  1. Flux

    DEFF Research Database (Denmark)

    Ravn, Ib

    . FLUX betegner en flyden eller strømmen, dvs. dynamik. Forstår man livet som proces og udvikling i stedet for som ting og mekanik, får man et andet billede af det gode liv end det, som den velkendte vestlige mekanicisme lægger op til. Dynamisk forstået indebærer det gode liv den bedst mulige...... kanalisering af den flux eller energi, der strømmer igennem os og giver sig til kende i vore daglige aktiviteter. Skal vores tanker, handlinger, arbejde, samvær og politiske liv organiseres efter stramme og faste regelsæt, uden slinger i valsen? Eller skal de tværtimod forløbe ganske uhindret af regler og bånd...

  2. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    International Nuclear Information System (INIS)

    Chesca, Boris; John, Daniel; Mellor, Christopher J.

    2015-01-01

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S Φ 1/2 decreases as 1/N 1/2 . Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa 2 Cu 3 O 7 . Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S Φ 1/2 between (0.25 and 0.44) μΦ 0 /Hz 1/2 for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications

  3. Temperature fluctuations superimposed on background temperature change

    International Nuclear Information System (INIS)

    Otto, James; Roberts, J.A.

    2016-01-01

    Proxy data allows the temperature of the Earth to be mapped over long periods of time. In this work the temperature fluctuations for over 200 proxy data sets were examined and from this set 50 sets were analyzed to test for periodic and quasi-periodic fluctuations in the data sets. Temperature reconstructions over 4 different time scales were analyzed to see if patterns emerged. Data were put into four time intervals; 4,000 years, 14,000 years, 1,000,000 years, and 3,000,000 years and analyzed with a goal to understanding periodic and quasi-periodic patterns in global temperature change superimposed on a “background” average temperature change. Quasi-periodic signatures were identified that predate the Industrial Revolution, during much of which direct data on temperature are not available. These data indicate that Earth temperatures have undergone a number of periodic and quasi-periodic intervals that contain both global warming and global cooling cycles. The fluctuations are superimposed on a background of temperature change that has a declining slope during the two periods, pre-ice age and post ice age with a transition about 12,000 BCE. The data are divided into “events” that span the time periods 3,000,000 BCE to “0” CE, 1,000,000 BCE to “0” CE, 12,000 BCE to 2,000 CE and 2,000 BCE to 2,000 CE. An equation using a quasi-periodic (frequency modulated sine waves) patterns was developed to analyze the date sets for quasi-periodic patterns. “Periodicities” which show reasonable agreement with the predictions of Milankovitch and other investigators were found in the data sets.

  4. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

    Energy Technology Data Exchange (ETDEWEB)

    Chesca, Boris, E-mail: B.Chesca@lboro.ac.uk; John, Daniel [Department of Physics, Loughborough University, Loughborough LE11 3TU (United Kingdom); Mellor, Christopher J. [School of Physics and Astronomy, Nottingham University, Nottingham NG7 2RD (United Kingdom)

    2015-10-19

    A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise S{sub Φ}{sup 1/2} decreases as 1/N{sup 1/2}. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa{sub 2}Cu{sub 3}O{sub 7}. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for S{sub Φ}{sup 1/2} between (0.25 and 0.44) μΦ{sub 0}/Hz{sup 1/2} for temperatures in the range (77–83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10–17) mV and (0.3–2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications.

  5. Numerical investigation of edge plasma phenomena in an enhanced D-alpha discharge at Alcator C-Mod: Parallel heat flux and quasi-coherent edge oscillations

    International Nuclear Information System (INIS)

    Russell, D. A.; D’Ippolito, D. A.; Myra, J. R.; LaBombard, B.; Terry, J. L.; Zweben, S. J.

    2012-01-01

    Reduced-model scrape-off layer turbulence (SOLT) simulations of an enhanced D-alpha (EDA) H-mode shot observed in the Alcator C-Mod tokamak were conducted to compare with observed variations in the scrape-off-layer (SOL) width of the parallel heat flux profile. In particular, the role of the competition between sheath- and conduction-limited parallel heat fluxes in determining that width was studied for the turbulent SOL plasma that emerged from the simulations. The SOL width decreases with increasing input power and with increasing separatrix temperature in both the experiment and the simulation, consistent with the strong temperature dependence of the parallel heat flux in balance with the perpendicular transport by turbulence and blobs. The particularly strong temperature dependence observed in the case analyzed is attributed to the fact that these simulations produce SOL plasmas which are in the conduction-limited regime for the parallel heat flux. A persistent quasi-coherent (QC) mode dominates the SOLT simulations and bears considerable resemblance to the QC mode observed in C-Mod EDA operation. The SOLT QC mode consists of nonlinearly saturated wave-fronts located just inside the separatrix that are convected poloidally by the mean flow, continuously transporting particles and energy and intermittently emitting blobs into the SOL.

  6. Modelling snow ice and superimposed ice on landfast sea ice in Kongsfjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    Caixin Wang

    2015-08-01

    Full Text Available Snow ice and superimposed ice formation on landfast sea ice in a Svalbard fjord, Kongsfjorden, was investigated with a high-resolution thermodynamic snow and sea-ice model, applying meteorological weather station data as external forcing. The model shows that sea-ice formation occurs both at the ice bottom and at the snow/ice interface. Modelling results indicated that the total snow ice and superimposed ice, which formed at the snow/ice interface, was about 14 cm during the simulation period, accounting for about 15% of the total ice mass and 35% of the total ice growth. Introducing a time-dependent snow density improved the modelled results, and a time-dependent oceanic heat flux parameterization yielded reasonable ice growth at the ice bottom. Model results suggest that weather conditions, in particular air temperature and precipitation, as well as snow thermal properties and surface albedo are the most critical factors for the development of snow ice and superimposed ice in Kongsfjorden. While both warming air and higher precipitation led to increased snow ice and superimposed ice forming in Kongsfjorden in the model runs, the processes were more sensitive to precipitation than to air temperature.

  7. 4. 7s nearly periodic oscillations superimposed on the solar microwave great burst of 28 March 1976

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, P; Piazza, L R; Raffaelli, J C [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica

    1977-09-01

    An unusual fast oscillation was found superimposed on the solar great burst on 28 March 1976, as measured at 7 GHz. The period of the oscillation was 4.7 +- 0.9 s, defined over the entire duration of the event. The amplitude of the oscillation was proportional to the flux density in the range 50flux units. The degree of circular polarization has not shown any fast periodic time structure.

  8. Additional ion bombardment in PVD processes generated by a superimposed pulse bias voltage

    International Nuclear Information System (INIS)

    Olbrich, W.; Kampschulte, G.

    1993-01-01

    The superimposed pulse bias voltage is a tool to apply an additional ion bombardment during deposition in physical vapour deposition (PVD) processes. It is generated by the combination of a d.c. ground voltage and a higher d.c. pulse voltage. Using a superimposed pulse bias voltage in ion-assisted PVD processes effects an additional all-around ion bombardment on the surface with ions of higher energy. Both metal and reactive or inert-gas ions are accelerated to the surface. The basic principles and important characteristics of this newly developed process such as ion fluxes or deposition rates are shown. Because of pulsing the high voltage, the deposition temperature does not increase much. The adhesion, structure, morphology and internal stresses are influenced by these additional ion impacts. The columnar growth of the deposited films could be suppressed by using the superimposed pulse bias voltage without increasing the deposition temperature. Different metallizations (Cr and Cu) produced by arc and sputter ion plating are investigated. Carbon-fibre-reinforced epoxy are coated with PVD copper films for further treatment in electrochemical processes. (orig.)

  9. Topological Properties of Spatial Coherence Function

    International Nuclear Information System (INIS)

    Ji-Rong, Ren; Tao, Zhu; Yi-Shi, Duan

    2008-01-01

    The topological properties of the spatial coherence function are investigated rigorously. The phase singular structures (coherence vortices) of coherence function can be naturally deduced from the topological current, which is an abstract mathematical object studied previously. We find that coherence vortices are characterized by the Hopf index and Brouwer degree in topology. The coherence flux quantization and the linking of the closed coherence vortices are also studied from the topological properties of the spatial coherence function

  10. Dynamic and static strain gauge using superimposed fiber Bragg gratings

    International Nuclear Information System (INIS)

    Ma, Y C; Yang, Y H; Yang, M W; Li, J M; Tang, J; Liang, T

    2012-01-01

    This paper demonstrates a simple and fast interrogation method for the dynamic and/or static strain gauge using a reflection spectrum from two superimposed fiber Bragg gratings (FBGs). The superimposed FBGs are designed to decrease nonequidistant space of generated a sensing pulse train in a time domain during dynamic strain gauge. By combining centroid finding with smooth filtering methods, both the interrogation speed and accuracy are improved. A four times increase in the interrogation speed of dynamic strain, by generating a 2 kHz optical sensing pulse train from a 500 Hz scanning frequency, is demonstrated experimentally. The interrogation uncertainty and total harmonic distortion characterization of superimposed FBGs are tested and less than 4 pm standard deviation is obtained. (paper)

  11. Selective attention in vision: recognition memory for superimposed line drawings.

    Science.gov (United States)

    Goldstein, E B; Fink, S I

    1981-10-01

    These experiments show that observers can selectively attend to one of two stationary superimposed pictures. If superimposed line drawings are presented to observers who are told to attend to one line drawing in the pair and to ignore the other line drawing in the pair, then a subsequent recognition test in which the pictures are presently singly, the attended picture in each pair is recognized much more frequently than the unattended picture in each pair. This selective recognition occurs both with large (11 degrees-22 degrees) displays in which observers are free to make eye movements during a 3-sec exposure and with small (1 degree) displays in which observers are instructed to fixate steadily on a point during a 1-sec exposure. The results of the steady fixation experiments show that in the absence of eye movements, attention to one of two superimposed stimuli can cause an observer to remember the attended image and not to remember the other, clearly visible, unattended image in a superimposed pair.

  12. Selective Attention in Vision: Recognition Memory for Superimposed Line Drawings.

    Science.gov (United States)

    Goldstein, E. Bruce; Fink, Susan I.

    1981-01-01

    Four experiments show that observers can selectively attend to one of two stationary superimposed pictures. Selective recognition occurred with large displays in which observers were free to make eye movements during a 3-sec exposure and with small displays in which observers were instructed to fixate steadily on a point. (Author/RD)

  13. Tools to Detect Delirium Superimposed on Dementia: A Systematic Review

    Science.gov (United States)

    Morandi, Alessandro; McCurley, Jessica; Vasilevskis, Eduard E.; Fick, Donna M.; Bellelli, Giuseppe; Lee, Patricia; Jackson, James C.; Shenkin, Susan D.; Trabucchi, Marco; Schnelle, John; Inouye, Sharon K.; Ely, Wesley E.; MacLullich, Alasdair

    2012-01-01

    Background Delirium commonly occurs in patients with dementia. Though several tools for detecting delirium exist, it is unclear which are valid in patients with delirium superimposed on dementia. Objectives Identify valid tools to diagnose delirium superimposed on dementia Design We performed a systematic review of studies of delirium tools, which explicitly included patients with dementia. Setting In-hospital patients Participants Studies were included if delirium assessment tools were validated against standard criteria, and the presence of dementia was assessed according to standard criteria that used validated instruments. Measurements PubMed, Embase, and Web of Science databases were searched for articles in English published between January 1960 and January 2012. Results Nine studies fulfilled the selection criteria. Of the total of 1569 patients, 401 had dementia, and 50 had delirium superimposed on dementia. Six delirium tools were evaluated. One studyusing the Confusion Assessment Method (CAM) with 85% patients with dementia showed a high specificity (96–100%) and moderate sensitivity (77%).Two intensive care unit studies that used the CAM for the Intensive Care Unit (CAM-ICU) ICU reported 100% sensitivity and specificity for delirium among 23 dementia patients. One study using electroencephalography reported a sensitivity of 67% and a specificity of 91% among a population with 100% prevalence of dementia. No studies examined potential effects of dementia severity or subtype upon diagnostic accuracy. Conclusions The evidence base on tools for detection of delirium superimposed on dementia is limited, although some existing tools show promise. Further studies of existing or refined tools with larger samples and more detailed characterization of dementia are now required to address the identification of delirium superimposed on dementia. PMID:23039270

  14. Valencia's Palau d'En Bou. Superimposed architectures.

    Directory of Open Access Journals (Sweden)

    Rafael Soler Verdú

    1997-09-01

    Full Text Available The restoration of the Palau díen Bou is a sample of the complexity that arises when practising an intervention on a building with indefinite superimposed architectures, in other words, an accumulation of interventions from different periods and in different styles, but difficult to understand in its original condition. Architect Rafael Soler describes his reading and interpretation of the building during the initial study and the solutions recommended by research that were applied during the restoration stage

  15. Current-voltage characteristics of a superconducting slab under a superimposed small AC magnetic field

    International Nuclear Information System (INIS)

    Matsushita, Teruo; Yamafuji, Kaoru; Sakamoto, Nobuyoshi.

    1977-01-01

    In case of applying superconductors to electric machinery or high intensity field magnets for fusion reactors, the superconductors are generally expected to be sensible to small field fluctuation besides DC magnetic field. The behavior of superconductors in DC magnetic field superimposed with small AC magnetic field has been investigated often experimentally, and the result has been obtained that the critical current at which DC flow voltage begins to appear extremely decreased or disappeared. Some theoretical investigations have been carried out on this phenomenon so far, however, their application has been limited to the region where frequency is sufficiently low or which is close to the critical magnetic field. Purpose of this report is to deal with the phenomenon in more unified way by analyzing the behavior of magnetic flux lines in a superconductor under a superimposed small AC field using the criticalstate model including viscous force. In order to solve the fundamental equation in this report, first the solution has been obtained in the quasi-static state neglecting viscous force, then about the cases that current density J is not more than Jc and J is larger than Jc, concerning the deviation from the quasi-static limit by employing successive approximation. Current-voltage characteristics have been determined by utilizing the above results. This method seems to be most promising at present except the case of extremely high frequency. (Wakatsuki, Y.)

  16. Physicochemical analog for modeling superimposed and coded memories

    Science.gov (United States)

    Ensanian, Minas

    1992-07-01

    The mammalian brain is distinguished by a life-time of memories being stored within the same general region of physicochemical space, and having two extraordinary features. First, memories to varying degrees are superimposed, as well as coded. Second, instantaneous recall of past events can often be affected by relatively simple, and seemingly unrelated sensory clues. For the purposes of attempting to mathematically model such complex behavior, and for gaining additional insights, it would be highly advantageous to be able to simulate or mimic similar behavior in a nonbiological entity where some analogical parameters of interest can reasonably be controlled. It has recently been discovered that in nonlinear accumulative metal fatigue memories (related to mechanical deformation) can be superimposed and coded in the crystal lattice, and that memory, that is, the total number of stress cycles can be recalled (determined) by scanning not the surfaces but the `edges' of the objects. The new scanning technique known as electrotopography (ETG) now makes the state space modeling of metallic networks possible. The author provides an overview of the new field and outlines the areas that are of immediate interest to the science of artificial neural networks.

  17. Investigation of optical currents in coherent and partially coherent vector fields

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Gorsky, M. P.; Maksimyak, P. P.

    2011-01-01

    We present the computer simulation results of the spatial distri-bution of the Poynting vector and illustrate motion of micro and nanopar-ticles in spatially inhomogeneously polarized fields. The influence of phase relations and the degree of mutual coherence of superimposing waves...... by polarization characteristics of an optical field alone, using nanoscale me-tallic particles has been shown experimentally....

  18. Quantum Properties of the Superposition of Two Nearly Identical Coherent States

    Science.gov (United States)

    Othman, Anas; Yevick, David

    2018-04-01

    In this paper, we examine the properties of the state obtained when two nearly identical coherent states are superimposed. We found that this state exhibits many nonclassical properties such as sub-Poissonian statistics, squeezing and a partially negative Wigner function. These and other properties indicate that such states, here termed near coherent states, are significantly closer to coherent states more than the generalized Schrördinger cat states. We finally provide an experimental procedure for generating the near coherent states.

  19. Discharge Characteristic of VHF-DC Superimposed Magnetron Sputtering System

    Science.gov (United States)

    Toyoda, Hirotaka; Fukuoka, Yushi; Fukui, Takashi; Takada, Noriharu; Sasai, Kensuke

    2014-10-01

    Magnetron plasmas are one of the most important tools for sputter deposition of thin films. However, energetic particles from the sputtered target such as backscattered rare gas atoms or oxygen negative ions from oxide targets sometimes induce physical and chemical damages as well as surface roughening to the deposited film surface during the sputtering processes. To suppress kinetic energy of such particles, superposition of RF or VHF power to the DC power has been investigated. In this study, influence of the VHF power superposition on the DC target voltage, which is important factor to determine kinetic energy of high energy particles, is investigated. In the study, 40 MHz VHF power was superimposed to an ITO target and decrease in the target DC voltage was measured as well as deposited film deposition properties such as deposition rate or electrical conductivity. From systematic measurement of the target voltage, it was revealed that the target voltage can be determined by a very simple parameter, i.e., a ratio of VHF power to the total input power (DC and VHF powers) in spite of the DC discharge current. Part of this work was supported by ASTEP, JST.

  20. Superimposed Training-Based Channel Estimation for MIMO Relay Networks

    Directory of Open Access Journals (Sweden)

    Xiaoyan Xu

    2012-01-01

    Full Text Available We introduce the superimposed training strategy into the multiple-input multiple-output (MIMO amplify-and-forward (AF one-way relay network (OWRN to perform the individual channel estimation at the destination. Through the superposition of a group of additional training vectors at the relay subject to power allocation, the separated estimates of the source-relay and relay-destination channels can be obtained directly at the destination, and the accordance with the two-hop AF strategy can be guaranteed at the same time. The closed-form Bayesian Cramér-Rao lower bound (CRLB is derived for the estimation of two sets of flat-fading MIMO channel under random channel parameters and further exploited to design the optimal training vectors. A specific suboptimal channel estimation algorithm is applied in the MIMO AF OWRN using the optimal training sequences, and the normalized mean square error performance for the estimation is provided to verify the Bayesian CRLB results.

  1. Decision making by superimposing information from parallel cognitive channels

    Science.gov (United States)

    Aityan, Sergey K.

    1993-08-01

    A theory of decision making with perception through parallel information channels is presented. Decision making is considered a parallel competitive process. Every channel can provide confirmation or rejection of a decision concept. Different channels provide different impact on the specific concepts caused by the goals and individual cognitive features. All concepts are divided into semantic clusters due to the goals and the system defaults. The clusters can be alternative or complimentary. The 'winner-take-all' concept nodes firing takes place within the alternative cluster. Concepts can be independently activated in the complimentary cluster. A cognitive channel affects a decision concept by sending an activating or inhibitory signal. The complimentary clusters serve for building up complex concepts by superimposing activation received from various channels. The decision making is provided by the alternative clusters. Every active concept in the alternative cluster tends to suppress the competitive concepts in the cluster by sending inhibitory signals to the other nodes of the cluster. The model accounts for a time delay in signal transmission between the nodes and explains decreasing of the reaction time if information is confirmed by different channels and increasing of the reaction time if deceiving information received from the channels.

  2. The Diagnosis of Delirium Superimposed on Dementia: An Emerging Challenge

    Science.gov (United States)

    Morandi, Alessandro; Davis, Daniel; Bellelli, Giuseppe; Arora, Rakesh C.; Caplan, Gideon A.; Kamholz, Barbara; Kolanowski, Ann; Fick, Donna Marie; Kreisel, Stefan; MacLullich, Alasdair; (UK), MRCP; Meagher, David; Neufeld, Karen; Pandharipande, Pratik P.; Richardson, Sarah; Slooter, Arjen J.C.; Taylor, John P.; Thomas, Christine; Tieges, Zoë; Teodorczuk, Andrew; Voyer, Philippe; Rudolph, James L.

    2017-01-01

    Delirium occurring in patients with dementia is referred to as delirium superimposed on dementia (DSD). People who are older with dementia and who are institutionalized are at increased risk of developing delirium when hospitalized. In addition, their prior cognitive impairment makes detecting their delirium a challenge. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Statistical Classification of Diseases and Related Health Problems, 10th Revision are considered the standard reference for the diagnosis of delirium and include criteria of impairments in cognitive processes such as attention, additional cognitive disturbances, or altered level of arousal. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition and the International Statistical Classification of Diseases and Related Health Problems, 10th Revision does not provide guidance regarding specific tests for assessment of the cognitive process impaired in delirium. Importantly, the assessment or inclusion of preexisting cognitive impairment is also not addressed by these standards. The challenge of DSD gets more complex as types of dementia, particularly dementia with Lewy bodies, which has features of both delirium and dementia, are considered. The objective of this article is to critically review key elements for the diagnosis of DSD, including the challenge of neuropsychological assessment in patients with dementia and the influence of particular tests used to diagnose DSD. To address the challenges of DSD diagnosis, we present a framework for guiding the focus of future research efforts to develop a reliable reference standard to diagnose DSD. A key feature of a reliable reference standard will improve the ability to clinically diagnose DSD in facility-based patients and research studies. PMID:27650668

  3. Palatoplasty with flap superimposed in dog - Case report

    Directory of Open Access Journals (Sweden)

    Luis Gustavo Gosuen Gonçalves Dias

    2015-10-01

    Full Text Available ABSTRACT. Gonçalves Dias L.G.G., Gonçalves Dias F.G.G., Ikenaga F.M., Honsho C.S., Souza F.F., Selmi A.L. & Mattos Junior E. [Palatoplasty with flap superimposed in dog - Case report.] Palatoplastia com retalho sobreposto em cão - Relato de caso. Revista Brasileira de Medicina Veterinária, 37(3:179-185, 2015. Curso de Graduação em Medicina Veterinária e Programa de Pós-Graduação Stricto Sensu em Medicina Veterinária de Pequenos Animais, Universidade de Franca, Av. Dr. Armando Salles de Oliveira, 201, Parque Universitário, Cx. Postal 82, Franca, SP 14404-600, Brasil. E-mail: luisgd@unifran.br The oral cleft palate deformities are characterized by disruption in the integrity of the bone and palatal mucosa, having variable extensions and multifactorial etiologic character. Frequently are unnoticed by owners and veterinarians at birth and are diagnosed only when the animal begins to demonstrate clinical respiratory signs. Affected patients have direct communication between the oral and nasal cavity, which can cause aspiration pneumonia and hinder the negative intraoral pressure necessary for the suction of milk, these being factors contributors to the deficit in body growth and death. This paper aimed to highlight important points about this rare oral disease in small animals, moreover, report the case of a dog with cleft palate treated successfully with the technique of overlapping flap palatoplasty.

  4. Optical stress investigations of notched bars with superimposed types of loads

    International Nuclear Information System (INIS)

    Richard, H.A.; Theis, W.

    1982-01-01

    Starting from the notch effect for various types of load, notch stresses are determined by optical methods for superimposed tensile and shearing stress and for superimposed tensile and bending stress. The superimposed stresses are induced by a device developed at the Technical Mechanics Department of Kaiserslautern University; only tensile stress needs to be applied to this testing device. The investigations have shown that in notched bars subject to superimposed tensile and shearing stress, stress increases will be higher than the maximum values of the two types of stress. For superimposed tensile and bending stress, notches on the outer side of the test piece and eccentric notches on the inner side may lead to a considerable stress increase. However, the stress distribution can be improved by an optimum arrangement of notches. (orig.) [de

  5. Coherent Coupled Qubits for Quantum Annealing

    Science.gov (United States)

    Weber, Steven J.; Samach, Gabriel O.; Hover, David; Gustavsson, Simon; Kim, David K.; Melville, Alexander; Rosenberg, Danna; Sears, Adam P.; Yan, Fei; Yoder, Jonilyn L.; Oliver, William D.; Kerman, Andrew J.

    2017-07-01

    Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times limited primarily by the use of large persistent currents Ip. Here, we examine an alternative approach using qubits with smaller Ip and longer coherence times. We demonstrate tunable coupling, a basic building block for quantum annealing, between two flux qubits with small (approximately 50-nA) persistent currents. Furthermore, we characterize qubit coherence as a function of coupler setting and investigate the effect of flux noise in the coupler loop on qubit coherence. Our results provide insight into the available design space for next-generation quantum annealers with improved coherence.

  6. Superimposed disturbance in the ionosphere triggered by spacecraft launches in China

    OpenAIRE

    L. M. He; L. X. Wu; L. X. Wu; S. J. Liu; S. N. Liu

    2015-01-01

    Using GPS dual-frequency observations collected by continuously operating GPS tracking stations in China, superimposed disturbances caused by the integrated action of spacecraft's physical effect and chemical effect on ionosphere during the launches of the spacecrafts Tiangong-1 and Shenzhou-8 in China were firstly determined. The results show that the superimposed disturbance was composed of remarkable ionospheric waves and significant ionospheric depletion emerged after bo...

  7. Coherent detectors

    International Nuclear Information System (INIS)

    Lawrence, C R; Church, S; Gaier, T; Lai, R; Ruf, C; Wollack, E

    2009-01-01

    Coherent systems offer significant advantages in simplicity, testability, control of systematics, and cost. Although quantum noise sets the fundamental limit to their performance at high frequencies, recent breakthroughs suggest that near-quantum-limited noise up to 150 or even 200 GHz could be realized within a few years. If the demands of component separation can be met with frequencies below 200 GHz, coherent systems will be strong competitors for a space CMB polarization mission. The rapid development of digital correlator capability now makes space interferometers with many hundreds of elements possible. Given the advantages of coherent interferometers in suppressing systematic effects, such systems deserve serious study.

  8. Coherent detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, C R [M/C 169-327, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Church, S [Room 324 Varian Physics Bldg, 382 Via Pueblo Mall, Stanford, CA 94305-4060 (United States); Gaier, T [M/C 168-314, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Lai, R [Northrop Grumman Corporation, Redondo Beach, CA 90278 (United States); Ruf, C [1533 Space Research Building, The University of Michigan, Ann Arbor, MI 48109-2143 (United States); Wollack, E, E-mail: charles.lawrence@jpl.nasa.go [NASA/GSFC, Code 665, Observational Cosmology Laboratory, Greenbelt, MD 20771 (United States)

    2009-03-01

    Coherent systems offer significant advantages in simplicity, testability, control of systematics, and cost. Although quantum noise sets the fundamental limit to their performance at high frequencies, recent breakthroughs suggest that near-quantum-limited noise up to 150 or even 200 GHz could be realized within a few years. If the demands of component separation can be met with frequencies below 200 GHz, coherent systems will be strong competitors for a space CMB polarization mission. The rapid development of digital correlator capability now makes space interferometers with many hundreds of elements possible. Given the advantages of coherent interferometers in suppressing systematic effects, such systems deserve serious study.

  9. Superimpose of images by appending two simple video amplifier circuits to color television

    International Nuclear Information System (INIS)

    Kojima, Kazuhiko; Hiraki, Tatsunosuke; Koshida, Kichiro; Maekawa, Ryuichi; Hisada, Kinichi.

    1979-01-01

    Images are very useful to obtain diagnostic informations in medical fields. Also by superimposing two or three images obtained from the same patient, various informations, for example a degree of overlapping and anatomical land mark, which can not be found in only one image, can be often found. In this paper characteristics of our trial color television system for the purpose of superimposing x-ray images and/or radionuclide images are described. This color television system superimposing two images in each different color consists of two monochromatic vidicon cameras and 20 inches conventional color television in which only two simple video amplifier circuits are added. Signals from vidicon cameras are amplified about 40 dB and are directly applied to cathode terminals of color CRT in the television. This system is very simple and economical color displays, and enhance a degree of overlapping and displacement between images. As one of typical clinical applications, pancreas images were superimposed in color by this method. As a result, size and position of pancreas was enhanced. Also x-ray image and radionuclide image were superimposed to find exactly the position of tumors. Furthermore this system was very useful for color display of multinuclides scintigraphy. (author)

  10. Superimpose of images by appending two simple video amplifier circuits to color television

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, K; Hiraki, T; Koshida, K; Maekawa, R [Kanazawa Univ. (Japan). School of Paramedicine; Hisada, K

    1979-09-01

    Images are very useful to obtain diagnostic informations in medical fields. Also by superimposing two or three images obtained from the same patient, various informations, for example a degree of overlapping and anatomical land mark, which can not be found in only one image, can be often found. In this paper characteristics of our trial color television system for the purpose of superimposing x-ray images and/or radionuclide images are described. This color television system superimposing two images in each different color consists of two monochromatic vidicon cameras and 20 inches conventional color television in which only two simple video amplifier circuits are added. Signals from vidicon cameras are amplified about 40 dB and are directly applied to cathode terminals of color CRT in the television. This system is very simple and economical color displays, and enhance a degree of overlapping and displacement between images. As one of typical clinical applications, pancreas images were superimposed in color by this method. As a result, size and position of pancreas was enhanced. Also x-ray image and radionuclide image were superimposed to find exactly the position of tumors. Furthermore this system was very useful for color display of multinuclides scintigraphy.

  11. Diffraction coherence in optics

    CERN Document Server

    Françon, M; Green, L L

    2013-01-01

    Diffraction: Coherence in Optics presents a detailed account of the course on Fraunhofer diffraction phenomena, studied at the Faculty of Science in Paris. The publication first elaborates on Huygens' principle and diffraction phenomena for a monochromatic point source and diffraction by an aperture of simple form. Discussions focus on diffraction at infinity and at a finite distance, simplified expressions for the field, calculation of the path difference, diffraction by a rectangular aperture, narrow slit, and circular aperture, and distribution of luminous flux in the airy spot. The book th

  12. Identification of igneous rocks in a superimposed basin through integrated interpretation dominantly based on magnetic data

    Science.gov (United States)

    LI, S.

    2017-12-01

    Identification of igneous rocks in the basin environment is of great significance to the exploration for hydrocarbon reservoirs hosted in igneous rocks. Magnetic methods are often used to alleviate the difficulties faced by seismic imaging in basins with thick cover and complicated superimposed structures. We present a case study on identification of igneous rocks in a superimposed basin through integrated interpretation based on magnetic and other geophysical data sets. The study area is located in the deepest depression with sedimentary cover of 14,000 m in Huanghua basin, which is a Cenozoic basin superimposed on a residual pre-Cenozoic basin above the North China craton. Cenozoic and Mesozoic igneous rocks that are dominantly intermediate-basic volcanic and intrusive rocks are widespread at depth in the basin. Drilling and seismic data reveal some volcanic units and intrusive rocks in Cenozoic stratum at depths of about 4,000 m. The question remains to identify the lateral extent of igneous rocks in large depth and adjacent areas. In order to tackle the difficulties for interpretation of magnetic data arisen from weak magnetic anomaly and remanent magnetization of igneous rocks buried deep in the superimposed basin, we use the preferential continuation approach to extract the anomaly and magnetic amplitude inversion to image the 3D magnetic units. The resultant distribution of effective susceptibility not only correlates well with the locations of Cenozoic igneous rocks known previously through drilling and seismic imaging, but also identifies the larger scale distribution of Mesozoic igneous rocks at greater depth in the west of the basin. The integrated interpretation results dominantly based on magnetic data shows that the above strategy is effective for identification of igneous rocks deep buried in the superimposed basin. Keywords: Identification of igneous rocks; Superimposed basin; Magnetic data

  13. A dual-wavelength tunable laser with superimposed fiber Bragg gratings

    International Nuclear Information System (INIS)

    Álvarez-Tamayo, R I; Durán-Sánchez, M; Pottiez, O; Ibarra-Escamilla, B; Kuzin, E A; Cruz, J L; Andrés, M V

    2013-01-01

    We report a dual-wavelength tunable fiber laser. The cavity is formed by two superimposed fiber Bragg gratings (FBGs) and a temperature tunable high-birefringence fiber optical loop mirror (FOLM). FBGs with wavelengths of 1548.5 and 1538.5 nm were printed in the same section of a fiber using two different masks. The superimposed FBGs were placed on a mechanical mount that allows stretch or compression of the FBGs. As a result of the FBG strain both lines are shifted simultaneously. Dual-wavelength generation requires a fine adjustment of the cavity loss for both wavelengths. (paper)

  14. Additive non-uniform random sampling in superimposed fiber Bragg grating strain gauge

    International Nuclear Information System (INIS)

    Ma, Y C; Liu, H Y; Yan, S B; Li, J M; Tang, J; Yang, Y H; Yang, M W

    2013-01-01

    This paper demonstrates an additive non-uniform random sampling and interrogation method for dynamic and/or static strain gauge using a reflection spectrum from two superimposed fiber Bragg gratings (FBGs). The superimposed FBGs are designed to generate non-equidistant space of a sensing pulse train in the time domain during dynamic strain gauge. By combining centroid finding with smooth filtering methods, both the interrogation speed and accuracy are improved. A 1.9 kHz dynamic strain is measured by generating an additive non-uniform randomly distributed 2 kHz optical sensing pulse train from a mean 500 Hz triangular periodically changing scanning frequency. (paper)

  15. Additive non-uniform random sampling in superimposed fiber Bragg grating strain gauge

    Science.gov (United States)

    Ma, Y. C.; Liu, H. Y.; Yan, S. B.; Yang, Y. H.; Yang, M. W.; Li, J. M.; Tang, J.

    2013-05-01

    This paper demonstrates an additive non-uniform random sampling and interrogation method for dynamic and/or static strain gauge using a reflection spectrum from two superimposed fiber Bragg gratings (FBGs). The superimposed FBGs are designed to generate non-equidistant space of a sensing pulse train in the time domain during dynamic strain gauge. By combining centroid finding with smooth filtering methods, both the interrogation speed and accuracy are improved. A 1.9 kHz dynamic strain is measured by generating an additive non-uniform randomly distributed 2 kHz optical sensing pulse train from a mean 500 Hz triangular periodically changing scanning frequency.

  16. Glucose clearance in aged trained skeletal muscle during maximal insulin with superimposed exercise

    DEFF Research Database (Denmark)

    Dela, Flemming; Mikines, K J; Larsen, J J

    1999-01-01

    Insulin and muscle contractions are major stimuli for glucose uptake in skeletal muscle and have in young healthy people been shown to be additive. We studied the effect of superimposed exercise during a maximal insulin stimulus on glucose uptake and clearance in trained (T) (1-legged bicycle tra...

  17. Superimposed chirped pulse parameter estimation based on the extended Kalman filter (EKF)

    CSIR Research Space (South Africa)

    Olivier, JC

    2009-05-01

    Full Text Available An extended Kalman filter (EKF) is proposed to estimate the frequencies and chirp rate of multiple superimposed chirped pulses. The estimation problem is a difficult one, where maximum likelyhood methods are very complex especially if more than two...

  18. Resemblance of the properties of superimposed volume holograms to the properties of human memory

    Science.gov (United States)

    Orlov, V. V.

    2006-09-01

    According to current concepts in psychology, a collection of patterns stored in human memory has the property of integrity and contains new information not contained in the individual patterns. It is shown that superimposed volume holograms possess similar properties if the information in them is written by a method that excludes the appearance of crosstalk of the holograms.

  19. Coherence and Sense of Coherence

    DEFF Research Database (Denmark)

    Dau, Susanne

    2014-01-01

    Constraints in the implementation of models of blended learning can be explained by several causes, but in this paper, it is illustrated that lack of sense of coherence is a major factor of these constraints along with the referential whole of the perceived learning environments. The question exa...

  20. Effects of Loaded Squat Exercise with and without Application of Superimposed EMS on Physical Performance

    Directory of Open Access Journals (Sweden)

    Nicolas Wirtz, Christoph Zinner, Ulrike Doermann, Heinz Kleinoeder, Joachim Mester

    2016-03-01

    Full Text Available The aim of the present study was to investigate the effects of a multiple set squat exercise training intervention with superimposed electromyostimulation (EMS on strength and power, sprint and jump performance. Twenty athletes from different disciplines participated and were divided into two groups: strength training (S or strength training with superimposed EMS (S+E. Both groups completed the same training program twice a week over a six week period consisting of four sets of the 10 repetition maximum of back squats. Additionally, the S+E group had EMS superimposed to the squat exercise with simultaneous stimulation of leg and trunk muscles. EMS intensity was adjusted to 70% of individual pain threshold to ensure dynamic movement. Strength and power of different muscle groups, sprint, and vertical jump performance were assessed one week before (pre, one week after (post and three weeks (re following the training period. Both groups showed improvements in leg press strength and power, countermovement and squat jump performance and pendulum sprint (p < 0.05, with no changes for linear sprint. Differences between groups were only evident at the leg curl machine with greater improvements for the S+E group (p < 0.05. Common squat exercise training and squat exercise with superimposed EMS improves maximum strength and power, as well as jumping abilities in athletes from different disciplines. The greater improvements in strength performance of leg curl muscles caused by superimposed EMS with improvements in strength of antagonistic hamstrings in the S+E group are suggesting the potential of EMS to unloaded (antagonistic muscle groups.

  1. Numerical Simulation of Damage during Forging with Superimposed Hydrostatic Pressure by Active Media

    International Nuclear Information System (INIS)

    Behrens, B.-A.; Hagen, T.; Roehr, S.; Sidhu, K. B.

    2007-01-01

    The effective reduction of energy consumption and a reasonable treatment of resources can be achieved by minimizing a component's weight using lightweight metals. In this context, aluminum alloys play a major role. Due to their material-sided restricted formability, the mentioned aluminum materials are difficult to form. The plasticity of a material is ascertained by its maximum forming limit. It is attained, when the deformation causes mechanical damage within the material. Damage of that sort is reached more rapidly, the greater the tensile strength rate in relation to total tension rate. A promising approach of handling these low ductile, high-strength aluminum alloys within a forming process, is forming with a synchronized superposition of comprehensive stress by active media such as by controlling oil pressure. The influence of superimposed hydrostatic pressure on the flow stress was analyzed as well as the formability for different procedures at different hydrostatic pressures and temperature levels. It was observed that flow stress is independent of superimposed hydrostatic pressure. Neither the superimposed pressure has an influence on the plastic deformation, nor does a pressure dependent material hardening due to increasing hydrostatic pressure take place. The formability increases with rising hydrostatic pressure. The relative gain at room temperature and increase of the superimposed pressure from 0 to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore in this paper, based on these experimental observations, it is the intended to develop a numerical simulation in order to predict ductile damage that occurs in the bulk forging process with superimposed hydrostatic pressure based Lemaitre's damage model

  2. Coherent Baryogenesis

    CERN Document Server

    Garbrecht, B; Schmidt, M G; Garbrecht, Bjorn; Prokopec, Tomislav; Schmidt, Michael G.

    2004-01-01

    We propose a new baryogenesis scenario based on coherent production and mixing of different fermionic species. The mechanism is operative during phase transitions, at which the fermions acquire masses via Yukawa couplings to scalar fields. Baryon production is efficient when the mass matrix is nonadiabatically varying, nonsymmetric and when it violates CP and B-L directly, or some other charges that are eventually converted to B-L. We first consider a toy model, which involves two mixing fermionic species, and then a hybrid inflationary scenario embedded in a supersymmetric Pati-Salam GUT. We show that, quite generically, a baryon excess in accordance with observation can result.

  3. Superimposed disturbance in the ionosphere triggered by spacecraft launches in China

    Science.gov (United States)

    He, L. M.; Wu, L. X.; Liu, S. J.; Liu, S. N.

    2015-11-01

    Using GPS dual-frequency observations collected by continuously operating GPS tracking stations in China, superimposed disturbances caused by the integrated action of spacecraft's physical effect and chemical effect on ionosphere during the launches of the spacecrafts Tiangong-1 and Shenzhou-8 in China were firstly determined. The results show that the superimposed disturbance was composed of remarkable ionospheric waves and significant ionospheric depletion emerged after both launches. Meanwhile, we found for the first time that the ionospheric waves were made up of two periods of wave by wavelet analysis. The first period of ∼ 4 min shows one event in the near stations and two sub-events in the few far stations. The second period of ∼ 9 min shows only one event in all the observed stations. Finally, the time characteristics for ionospheric waves and depletions were examined.

  4. Superimposed disturbance in the ionosphere triggered by spacecraft launches in China

    Directory of Open Access Journals (Sweden)

    L. M. He

    2015-11-01

    Full Text Available Using GPS dual-frequency observations collected by continuously operating GPS tracking stations in China, superimposed disturbances caused by the integrated action of spacecraft's physical effect and chemical effect on ionosphere during the launches of the spacecrafts Tiangong-1 and Shenzhou-8 in China were firstly determined. The results show that the superimposed disturbance was composed of remarkable ionospheric waves and significant ionospheric depletion emerged after both launches. Meanwhile, we found for the first time that the ionospheric waves were made up of two periods of wave by wavelet analysis. The first period of ∼ 4 min shows one event in the near stations and two sub-events in the few far stations. The second period of ∼ 9 min shows only one event in all the observed stations. Finally, the time characteristics for ionospheric waves and depletions were examined.

  5. Controlling total spot power from holographic laser by superimposing a binary phase grating.

    Science.gov (United States)

    Liu, Xiang; Zhang, Jian; Gan, Yu; Wu, Liying

    2011-04-25

    By superimposing a tunable binary phase grating with a conventional computer-generated hologram, the total power of multiple holographic 3D spots can be easily controlled by changing the phase depth of grating with high accuracy to a random power value for real-time optical manipulation without extra power loss. Simulation and experiment results indicate that a resolution of 0.002 can be achieved at a lower time cost for normalized total spot power.

  6. Spatial mapping of multi-year superimposed ice on the glacier Kongsvegen, Svalbard

    DEFF Research Database (Denmark)

    Brandt, Ola; Kohler, Jack; Lüthje, Mikael

    2008-01-01

    by GPR. Using the SI spatial depth distribution, we estimate the mean annual accumulation of superimposed ice to be 0.16 +/- 0.06 mw.e.a(-1) (locally up to 0.43 ma(-1) w.e.). This corresponds to similar to 15-33% of the local winter balance and similar to 5-10% of the total winter balance measured since...

  7. The effects of superimposed tilt and lower body negative pressure on anterior and posterior cerebral circulations

    OpenAIRE

    Tymko, Michael M.; Rickards, Caroline A.; Skow, Rachel J.; Ingram?Cotton, Nathan C.; Howatt, Michael K.; Day, Trevor A.

    2016-01-01

    Abstract Steady?state tilt has no effect on cerebrovascular reactivity to increases in the partial pressure of end?tidal carbon dioxide (PETCO 2). However, the anterior and posterior cerebral circulations may respond differently to a variety of stimuli that alter central blood volume, including lower body negative pressure (LBNP). Little is known about the superimposed effects of head?up tilt (HUT; decreased central blood volume and intracranial pressure) and head?down tilt (HDT; increased ce...

  8. Chronic hypertension and the risk for adverse pregnancy outcome after superimposed pre-eclampsia.

    Science.gov (United States)

    Vanek, M; Sheiner, E; Levy, A; Mazor, M

    2004-07-01

    To determine the risk factors and pregnancy outcome of patients with chronic hypertension during pregnancy after controlling for superimposed preeclampsia. A comparison of all singleton term (>36 weeks) deliveries occurring between 1988 and 1999, with and without chronic hypertension, was performed. Stratified analyses, using the Mantel-Haenszel technique, and a multiple logistic regression model were performed to control for confounders. Chronic hypertension complicated 1.6% (n=1807) of all deliveries included in the study (n=113156). Using a multivariable analysis, the following factors were found to be independently associated with chronic hypertension: maternal age >40 years (OR=3.1; 95% CI 2.7-3.6), diabetes mellitus (OR=3.6; 95% CI 3.3-4.1), recurrent abortions (OR=1.5; 95% CI 1.3-1.8), infertility treatment (OR=2.9; 95% CI 2.3-3.7), and previous cesarean delivery (CD; OR=1.8 CI 1.6-2.0). After adjustment for superimposed preeclampsia, using the Mantel-Haenszel technique, pregnancies complicated with chronic hypertension had higher rates of CD (OR=2.7; 95% CI 2.4-3.0), intra uterine growth restriction (OR=1.7; 95% CI 1.3-2.2), perinatal mortality (OR=1.6; 95% CI 1.01-2.6) and post-partum hemorrhage (OR=2.2; 95% CI 1.4-3.7). Chronic hypertension is associated with adverse pregnancy outcome, regardless of superimposed preeclampsia.

  9. Observation and modeling of snow melt and superimposed ice formation on sea ice

    OpenAIRE

    Nicolaus, Marcel; Haas, Christian

    2004-01-01

    Sea ice plays a key role within the global climate system. It covers some 7% of earths surface and processes a strong seasonal cycle. Snow on sea ice even amplifies the importance of sea ice in the coupled atmosphere-ice-ocean system, because it dominates surface properties and energy balance (incl. albedo).Several quantitative observations of summer sea ice and its snow cover show the formation of superimposed ice and a gap layer underneath, which was found to be associated to high standing ...

  10. Experimental Verification and Capacity Prediction of FE-OCDMA Using Superimposed FBG

    Science.gov (United States)

    Ayotte, Simon; Rochette, Martin; Magné, Julien; Rusch, Leslie A.; Larochelle, Sophie

    2005-02-01

    This paper presents the experimental demonstration and simulation results of a frequency-encoded optical code-division multiple-access (FE-OCDMA) system using broad-band incoherent source, superimposed fiber Bragg gratings for encoding/decoding of unipolar m -sequence codes, and balanced detection. The bit-error rate is measured for up to four simultaneous users at 155 and 622 Mb/s. Exploiting the excellent match between simulation and experiment, the paper concludes with a prediction of the potential capacity of an optimized FE-CDMA system.

  11. Properties of DLC coatings deposited by dc and dc with superimposed pulsed vacuum arc

    International Nuclear Information System (INIS)

    Zavaleyev, V.; Walkowicz, J.; Aksyonov, D.S.; Luchaninov, A.A.; Reshetnyak, E.N.; Strel'nitskij, V.E.

    2014-01-01

    Comparative studies of the structure, mechanical and tribological properties of DLC coatings deposited in DC and DC with superimposed high current pulse modes of operation vacuum-arc plasma source with the graphite cathode are presented. Imposition the pulses of high current on DC vacuum-arc discharge allows both increase the deposition rate of DLC coating and reduce the residual compressive stress in the coatings what promotes substantial improvement the adhesion to the substrate. Effect of vacuum arc plasma filtration with Venetian blind filter on the deposition rate and tribological characteristics of the coatings analyzed.

  12. Statistical mechanics of flux lines in high-temperature superconductors

    International Nuclear Information System (INIS)

    Dasgupta, C.

    1992-01-01

    The shortness of the low temperature coherence lengths of high T c materials leads to new mechanisms of pinning of flux lines. Lattice periodic modulations of the order parameters itself acts to pin vortex lines in regions of the unit cell were the order parameter is small. A presentation of flux creep and flux noise at low temperature and magnetic fields in terms of motion of simple metastable defects on flux lines is made, with a calculation of flux lattice melting. 12 refs

  13. Bilateral rapidly destructive arthrosis of the hip joint resulting from subchondral fracture with superimposed secondary osteonecrosis

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Takuaki; Iwamoto, Yukihide [Kyushu University, Department of Orthopaedic Surgery, Fukuoka (Japan); Schneider, Robert [Hospital for Special Surgery, Department of Radiology, New York (United States); Bullough, Peter G. [Hospital for Special Surgery, Department of Laboratory Medicine, New York, NY (United States)

    2010-02-15

    A 57-year-old woman suffered rapid destruction of both hip joints over a 10 months period. At the first visit, her radiographs demonstrated slight joint space narrowing and acetabular cyst formation in both hips. Five months later, joint space narrowing had further progressed, and intra-articular injection of steroid was given in both hips. However, the hip pain gradually became worse. Five months later, both joint spaces had totally disappeared and both femoral heads had undergone massive collapse. At gross examination, both resected femoral heads showed extensive opaque yellow areas consistent with osteonecrosis. Microscopic examination of these areas revealed evidence of both extensive fracture and callus formation, as well as necrosis throughout, indicating that the osteonecrosis observed in this case was a secondary phenomenon superimposed on pre-existing osteoarthritis and subchondral fracture. There were many pseudogranulomatous lesions in the marrow space and necrotic area, where tiny fragments of bone and articular cartilage, surrounded by histiocytes and giant cells, were embedded, such as are typically seen in rapidly destructive arthrosis. No radiologic or morphologic evidence of primary osteonecrosis was noted. This case indicates that at least some cases of rapidly destructive arthritis are the result of subchondral fracture with superimposed secondary osteonecrosis. (orig.)

  14. Bilateral rapidly destructive arthrosis of the hip joint resulting from subchondral fracture with superimposed secondary osteonecrosis

    International Nuclear Information System (INIS)

    Yamamoto, Takuaki; Iwamoto, Yukihide; Schneider, Robert; Bullough, Peter G.

    2010-01-01

    A 57-year-old woman suffered rapid destruction of both hip joints over a 10 months period. At the first visit, her radiographs demonstrated slight joint space narrowing and acetabular cyst formation in both hips. Five months later, joint space narrowing had further progressed, and intra-articular injection of steroid was given in both hips. However, the hip pain gradually became worse. Five months later, both joint spaces had totally disappeared and both femoral heads had undergone massive collapse. At gross examination, both resected femoral heads showed extensive opaque yellow areas consistent with osteonecrosis. Microscopic examination of these areas revealed evidence of both extensive fracture and callus formation, as well as necrosis throughout, indicating that the osteonecrosis observed in this case was a secondary phenomenon superimposed on pre-existing osteoarthritis and subchondral fracture. There were many pseudogranulomatous lesions in the marrow space and necrotic area, where tiny fragments of bone and articular cartilage, surrounded by histiocytes and giant cells, were embedded, such as are typically seen in rapidly destructive arthrosis. No radiologic or morphologic evidence of primary osteonecrosis was noted. This case indicates that at least some cases of rapidly destructive arthritis are the result of subchondral fracture with superimposed secondary osteonecrosis. (orig.)

  15. A System on a Programmable Chip Architecture for Data-Dependent Superimposed Training Channel Estimation

    Directory of Open Access Journals (Sweden)

    Fernando Martín del Campo

    2009-01-01

    with the information, a series of known symbols, whose analysis is used to define the parameters of the filters that remove the distortion of the data. Nevertheless, a part of the available bandwidth has to be destined to these symbols. Until now, no alternative solution has demonstrated to be fully satisfying for commercial use, but one technique that looks promising is superimposed training (ST. This work describes a hybrid software-hardware FPGA implementation of a recent algorithm that belongs to the ST family, known as Data-dependent Superimposed Training (DDST, which does not need extra bandwidth for its training sequences (TS as it adds them arithmetically to the data. DDST also adds a third sequence known as data-dependent sequence, that destroys the interference caused by the data over the TS. As DDST's computational burden is too high for the commercial processors used in mobile systems, a System on a Programmable Chip (SOPC approach is used in order to solve the problem.

  16. Manipulating Quantum Coherence in Solid State Systems

    CERN Document Server

    Flatté, Michael E; The NATO Advanced Study Institute "Manipulating Quantum Coherence in Solid State Systems"

    2007-01-01

    The NATO Advanced Study Institute "Manipulating Quantum Coherence in Solid State Systems", in Cluj-Napoca, Romania, August 29-September 9, 2005, presented a fundamental introduction to solid-state approaches to achieving quantum computation. This proceedings volume describes the properties of quantum coherence in semiconductor spin-based systems and the behavior of quantum coherence in superconducting systems. Semiconductor spin-based approaches to quantum computation have made tremendous advances in the past several years. Coherent populations of spins can be oriented, manipulated and detected experimentally. Rapid progress has been made towards performing the same tasks on individual spins (nuclear, ionic, or electronic) with all-electrical means. Superconducting approaches to quantum computation have demonstrated single qubits based on charge eigenstates as well as flux eigenstates. These topics have been presented in a pedagogical fashion by leading researchers in the fields of semiconductor-spin-based qu...

  17. Driving a mechanical resonator into coherent states via random measurements

    International Nuclear Information System (INIS)

    Garcia, Ll; Wu, L-A; Chhajlany, R W; Li, Y

    2013-01-01

    We propose dynamical schemes to engineer coherent states of a mechanical resonator (MR) coupled to an ancillary, superconducting flux qubit. The flux qubit, when repeatedly projected on to its ground state, drives the MR into a coherent state in probabilistic, albeit heralded fashion. Assuming no operations on the state of the MR during the protocol, coherent states are successfully generated only up to a certain value of the displacement parameter. This restriction can be overcome at the cost of a one-time operation on the initial state of the MR. We discuss the possibility of experimental realization of the presented schemes. (paper)

  18. The behaviour of radionuclides in gas adsorption chromatographic processes with superimposed chemical reactions (chlorides)

    International Nuclear Information System (INIS)

    Eichler, B.

    1996-01-01

    Thermochemical relationships are derived describing the gas adsorption chromatographic transport of carrier-free radionuclides. Especially, complex adsorption processes such as dissociative, associative and substitutive adsorption are dealt with. The comparison of experimental with calculated data allows the determination of the type of adsorption reaction, which is the basis of the respective gas chromatographic process. The behaviour of carrier-free radionuclides of elements Pu, Ce, Ru, Co and Cr in thermochromatographic experiments with chlorinating carrier gases can be described as dissociative adsorption of chlorides in higher oxidation states. The gas adsorption chromatographic transport of Zr with oxygen and chlorine containing carrier gas is shown to be a substitutive adsorption process. The consequences of superimposed chemical reactions on the interpretation of results and the conception of gas adsorption chromatographic experiments with carrier-free radionuclides in isothermal columns and in temperature gradient tubes is discussed. (orig.)

  19. A case of localized juvenile periodontitis: treatment and 3 years follow-up with superimposable radiographs.

    Science.gov (United States)

    Dubrez, B; Baehni, P; Cimasoni, G

    1996-06-01

    A 17-year-old male patient with localized juvenile periodontitis was treated by subgingival instrumentation with full thickness flap on the lower molars, combined with a 3-week course of systemic tetracycline, and a programme of supervised oral hygiene. The treatment was rapidly followed by dramatic clinical and microbiological improvement. However, despite good oral hygiene, gingival inflammation recurred at regular intervals. It was necessary to maintain the clinical results by periodic subgingival instrumentation with an ultrasonic scaler. Healing of alveolar bone was monitored in the lower 1st molar regions over 3 years by using superimposable radiographs. Quantitative analysis of bone density performed with a high-resolution digitalisation technique showed a considerable improvement 1 year after therapy. However, continuous remodelling, probably related to variations in inflammation, occurred during the 3 postoperative years.

  20. Resolving superimposed ground-water contaminant plumes characterized by chromium, nitrate, uranium, and technetium--99

    International Nuclear Information System (INIS)

    Hall, S.H.

    1990-02-01

    Leakage from a liquid waste storage and solar evaporation basin at the Hanford Site in southeastern Washington State has resulted in a ground-water contaminant plume characterized by nitrate, hexavalent chromium, uranium, and technetium-99. The plume is superimposed on a larger, pre-existing plume extending from upgradient sites and having the same suite of contaminants. However, the relative abundance of contaminant species is quite different for each plume source. Thus, characteristic concentration ratios, rather than concentrations of individual species, are used as geochemical tracers, with emphasis on graphical analysis. Accordingly, it has been possible to resolve the boundaries of the smaller plume and to estimate the contribution of each plume to the observed contamination downgradient from the storage basin. 11 refs., 7 figs

  1. Application of Semantic Tagging to Generate Superimposed Information on a Digital Encyclopedia

    Science.gov (United States)

    Garrido, Piedad; Tramullas, Jesus; Martinez, Francisco J.

    We can find in the literature several works regarding the automatic or semi-automatic processing of textual documents with historic information using free software technologies. However, more research work is needed to integrate the analysis of the context and provide coverage to the peculiarities of the Spanish language from a semantic point of view. This research work proposes a novel knowledge-based strategy based on combining subject-centric computing, a topic-oriented approach, and superimposed information. It subsequent combination with artificial intelligence techniques led to an automatic analysis after implementing a made-to-measure interpreted algorithm which, in turn, produced a good number of associations and events with 90% reliability.

  2. The theoretical shear strength of fcc crystals under superimposed triaxial stress

    Energy Technology Data Exchange (ETDEWEB)

    Cerny, M., E-mail: cerny.m@fme.vutbr.cz [Institute of Engineering Physics, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, CZ-616 69 Brno (Czech Republic); Pokluda, J. [Institute of Engineering Physics, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, CZ-616 69 Brno (Czech Republic)

    2010-05-15

    The influence of a triaxial stress applied normally to shear planes and shear direction during affine shear deformation of face-centered cubic crystals on the theoretical shear strength is studied for the <112-bar >{l_brace}111{r_brace} shear system using first-principles methods. The applied relaxation procedure guarantees that the modeled system is subjected to a superposition of shear, normal and in-plane stresses with individually adjustable in-plane and normal stress values. The theoretical shear strengths of individual elements prove to be qualitatively different functions of the superimposed stresses. In the special case of hydrostatic loading, however, these functions are qualitatively uniform. This behavior is discussed in terms of the electronic structure.

  3. Monte Carlo, hypothesis-tests for rare events superimposed on a background

    International Nuclear Information System (INIS)

    Avignone, F.T. III; Miley, H.S.; Padgett, W.J.; Weier, D.W.

    1985-01-01

    We describe two techniques to search for small numbers of counts under a peak of known shape and superimposed on a background with statistical fluctuations. Many comparisons of a single experimental spectrum with computer simulations of the peak and background are made. From these we calculate the probability that y hypothesized counts in the peaks of the simulations, will result in a number larger than that observed in a given energy interval (bin) in the experimental spectrum. This is done for many values of the hypothesized number y. One procedure is very similar to testing a statistical hypothesis and can be analytically applied. Another is presented which is related to pattern recognition techniques and is less sensitive to the uncertainty in the mean. Sample applications to double beta decay data are presented. (orig.)

  4. Cohering power of quantum operations

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Kaifeng, E-mail: bkf@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China); Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Zhang, Lin, E-mail: linyz@zju.edu.cn [Institute of Mathematics, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Junde, E-mail: wjd@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China)

    2017-05-18

    Highlights: • Quantum coherence. • Cohering power: production of quantum coherence by quantum operations. • Study of cohering power and generalized cohering power, and their comparison for differentmeasures of quantum coherence. • Operational interpretation of cohering power. • Bound on cohering power of a generic quantum operation. - Abstract: Quantum coherence and entanglement, which play a crucial role in quantum information processing tasks, are usually fragile under decoherence. Therefore, the production of quantum coherence by quantum operations is important to preserve quantum correlations including entanglement. In this paper, we study cohering power–the ability of quantum operations to produce coherence. First, we provide an operational interpretation of cohering power. Then, we decompose a generic quantum operation into three basic operations, namely, unitary, appending and dismissal operations, and show that the cohering power of any quantum operation is upper bounded by the corresponding unitary operation. Furthermore, we compare cohering power and generalized cohering power of quantum operations for different measures of coherence.

  5. Partially coherent imaging and spatial coherence wavelets

    International Nuclear Information System (INIS)

    Castaneda, Roman

    2003-03-01

    A description of spatially partially coherent imaging based on the propagation of second order spatial coherence wavelets and marginal power spectra (Wigner distribution functions) is presented. In this dynamics, the spatial coherence wavelets will be affected by the system through its elementary transfer function. The consistency of the model with the both extreme cases of full coherent and incoherent imaging was proved. In the last case we obtained the classical concept of optical transfer function as a simple integral of the elementary transfer function. Furthermore, the elementary incoherent response function was introduced as the Fourier transform of the elementary transfer function. It describes the propagation of spatial coherence wavelets form each object point to each image point through a specific point on the pupil planes. The point spread function of the system was obtained by a simple integral of the elementary incoherent response function. (author)

  6. Entangled Coherent States Generation in two Superconducting LC Circuits

    International Nuclear Information System (INIS)

    Chen Meiyu; Zhang Weimin

    2008-01-01

    We proposed a novel pure electronic (solid state) device consisting of two superconducting LC circuits coupled to a superconducting flux qubit. The entangled coherent states of the two LC modes is generated through the measurement of the flux qubit states. The interaction of the flux qubit and two LC circuits is controlled by the external microwave control lines. The geometrical structure of the LC circuits is adjustable and makes a strong coupling between them achievable. This entangled coherent state generator can be realized by using the conventional microelectronic fabrication techniques which increases the feasibility of the experiment.

  7. Validation of Lifetime Prediction of IGBT Modules Based on Linear Damage Accumulation by Means of Superimposed Power Cycling Tests

    DEFF Research Database (Denmark)

    Choi, Ui-Min; Ma, Ke; Blaabjerg, Frede

    2018-01-01

    In this paper, the lifetime prediction of power device modules based on the linear damage accumulation is studied in conjunction with simple mission profiles of converters. Superimposed power cycling conditions, which are called simple mission profiles in this paper, are made based on a lifetime ...... prediction of IGBT modules under power converter applications.......In this paper, the lifetime prediction of power device modules based on the linear damage accumulation is studied in conjunction with simple mission profiles of converters. Superimposed power cycling conditions, which are called simple mission profiles in this paper, are made based on a lifetime...... model in respect to junction temperature swing duration. This model has been built based on 39 power cycling test results of 600-V 30-A three-phase-molded IGBT modules. Six tests are performed under three superimposed power cycling conditions using an advanced power cycling test setup. The experimental...

  8. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between ...... observation sites and the turbulence intensity influence the results. The limitations of the theory are discussed....

  9. Fracture predictions for cracks exposed to superimposed normal and shear stresses

    International Nuclear Information System (INIS)

    Richard, H.A.

    1985-01-01

    The author developed a special device and a fracture mechanics specimen and proposed a procedure for determining the fracture toughness when Mixed Mode and Mode II stresses are applied. This device makes it possible to generate pure normal stresses, superimposed normal and shearing stresses as well as pure shearing stresses in the cross section of the crack in the specimen, as desired. The so-called CTS fracture mechanics specimen has an edge crack. The load is transferred statically determind from the device to the specimen by means of six studs altogether. The experiments described, which were carried out with specimens made of the brittle materials PMMA (Plexiglas) and Araldit B, clearly show that it is possible to evaluate the validity of the individual fracture hypotheses by suitable experiments. It is also found that the fracture behaviour of different materials varies considerably both in quality and quantity. In conclusion, a practice-oriented fracture criterion is indicated which enables a practice-conforming evaluation of Mixed-Mode crack problems, as is shown by way of examples. (orig./HP) [de

  10. Dataset of red light induced pupil constriction superimposed on post-illumination pupil response

    Directory of Open Access Journals (Sweden)

    Shaobo Lei

    2016-09-01

    Full Text Available We collected and analyzed pupil diameter data from of 7 visually normal participants to compare the maximum pupil constriction (MPC induced by “Red Only” vs. “Blue+Red” visual stimulation conditions.The “Red Only” condition consisted of red light (640±10 nm stimuli of variable intensity and duration presented to dark-adapted eyes with pupils at resting state. This condition stimulates the cone-driven activity of the intrinsically photosensitive retinal ganglion cells (ipRGC. The “Blue+Red” condition consisted of the same red light stimulus presented during ongoing blue (470±17 nm light-induced post-illumination pupil response (PIPR, representing the cone-driven ipRGC activity superimposed on the melanopsin-driven intrinsic activity of the ipRGCs (“The Absence of Attenuating Effect of Red light Exposure on Pre-existing Melanopsin-Driven Post-illumination Pupil Response” Lei et al. (2016 [1].MPC induced by the “Red Only” condition was compared with the MPC induced by the “Blue+Red” condition by multiple paired sample t-tests with Bonferroni correction. Keywords: Pupil light reflex, Chromatic pupillometry, Melanopsin, Post-illumination pupil response

  11. Superimposed noninterfering probes to extend the capabilities of phase Doppler anemometry.

    Science.gov (United States)

    Onofri, Fabrice; Lenoble, Anne; Radev, Stefan

    2002-06-20

    We propose using multiple superimposed noninterfering probes (SNIPs) of the same wavelength but different beam angles to extend the capabilities of phase Doppler anemometry. When a particle is moving in a SNIP the Doppler signals that are produced exhibit multiple Doppler frequencies and phase shifts. The resolution of the measurements of particle size (i.e., by fringe spacing and Doppler frequency) increases with beam angle. Then, with the solution proposed, even with only two detectors several measurements of size can be obtained for the same particle with increasing resolution if we consider higher frequencies in the signal. Several optical solutions to produce SNIPs as well as a signal-processing algorithm to treat the multiple-frequency Doppler signals are proposed. Experimental validations of the sizing of spherical and cylindrical particles demonstrate the applicability of this technique for particle measurement. We believe that this new technique can be of great interest when high resolution of size, velocity, and even refractive index is required.

  12. Configurable Transmitter and Systolic Channel Estimator Architectures for Data-Dependent Superimposed Training Communications Systems

    Directory of Open Access Journals (Sweden)

    E. Romero-Aguirre

    2012-01-01

    Full Text Available In this paper, a configurable superimposed training (ST/data-dependent ST (DDST transmitter and architecture based on array processors (APs for DDST channel estimation are presented. Both architectures, designed under full-hardware paradigm, were described using Verilog HDL, targeted in Xilinx Virtex-5 and they were compared with existent approaches. The synthesis results showed a FPGA slice consumption of 1% for the transmitter and 3% for the estimator with 160 and 115 MHz operating frequencies, respectively. The signal-to-quantization-noise ratio (SQNR performance of the transmitter is about 82 dB to support 4/16/64-QAM modulation. A Monte Carlo simulation demonstrates that the mean square error (MSE of the channel estimator implemented in hardware is practically the same as the one obtained with the floating-point golden model. The high performance and reduced hardware of the proposed architectures lead to the conclusion that the DDST concept can be applied in current communications standards.

  13. Optimal Superimposed Training Sequences for Channel Estimation in MIMO-OFDM Systems

    Directory of Open Access Journals (Sweden)

    Ratnam V. Raja Kumar

    2010-01-01

    Full Text Available In this work an iterative time domain Least Squares (LS based channel estimation method using superimposed training (ST for a Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM system over time varying frequency selective fading channels is proposed. The performance of the channel estimator is analyzed in terms of the Mean Square Estimation Error (MSEE and its impact on the uncoded Bit Error Rate (BER of the MIMO-OFDM system is studied. A new selection criterion for the training sequences that jointly optimizes the MSEE and the BER of the OFDM system is proposed. Chirp based sequences are proposed and shown to satisfy the same. These are compared with the other sequences proposed in the literature and are found to yield a superior performance. The sequences, one for each transmitting antenna, offers fairness through providing equal interference in all the data carriers unlike earlier proposals. The effectiveness of the mathematical analysis presented is demonstrated through a comparison with the simulation studies. Experimental studies are carried out to study and validate the improved performance of the proposed scheme. The scheme is applied to the IEEE 802.16e OFDM standard and a case is made with the required design of the sequence.

  14. Reliability of the Superimposed-Burst Technique in Patients With Patellofemoral Pain: A Technical Report.

    Science.gov (United States)

    Norte, Grant E; Frye, Jamie L; Hart, Joseph M

    2015-11-01

    The superimposed-burst (SIB) technique is commonly used to quantify central activation failure after knee-joint injury, but its reliability has not been established in pathologic cohorts. To assess within-session and between-sessions reliability of the SIB technique in patients with patellofemoral pain. Descriptive laboratory study. University laboratory. A total of 10 patients with self-reported patellofemoral pain (1 man, 9 women; age = 24.1 ± 3.8 years, height = 167.8 ± 15.2 cm, mass = 71.6 ± 17.5 kg) and 10 healthy control participants (3 men, 7 women; age = 27.4 ± 5.0 years, height = 173.5 ± 9.9 cm, mass = 78.2 ± 16.5 kg) volunteered. Participants were assessed at 6 intervals spanning 21 days. Intraclass correlation coefficients (ICCs [3,3]) were used to assess reliability. Quadriceps central activation ratio, knee-extension maximal voluntary isometric contraction force, and SIB force. The quadriceps central activation ratio was highly reliable within session (ICC [3,3] = 0.97) and between sessions through day 21 (ICC [3,3] = 0.90-0.95). Acceptable reliability of knee extension (ICC [3,3] = 0.75-0.91) and SIB force (ICC [3,3] = 0.77-0.89) was observed through day 21. The SIB technique was reliable for clinical research up to 21 days in patients with patellofemoral pain.

  15. RF-superimposed DC and pulsed DC sputtering for deposition of transparent conductive oxides

    International Nuclear Information System (INIS)

    Stowell, Michael; Mueller, Joachim; Ruske, Manfred; Lutz, Mark; Linz, Thomas

    2007-01-01

    Transparent conductive oxide films are widely used materials for electronic applications such as flat panel displays and solar cells. The superposition of DC and pulsed DC power by a certain fraction of RF power was applied to deposit indium tin oxide films. This technique allows an additional tuning of different parameters relevant to film growth, and yields high quality films even under kinetically limited conditions. A long-term stable RF/DC process could be realized by using different combinations of standard power supply components, which includes a fully reliable arc handling system for both the RF and DC generators. The effectiveness of the arc handling system is illustrated by the current and voltage behavior recorded for actual arcing events. The resistivity of indium tin oxide films is strongly influenced by the respective sputtering mode. The best resistivity values of 145-148 μΩ cm were obtained by RF-superimposed pulsed DC sputtering at a pulse frequency between 100 and 200 kHz and a substrate temperature as low as 140 deg. C. In addition, the films were extremely smooth with a surface roughness of 1-2.5 nm

  16. NO removal characteristics of a corona radical shower system under DC and AC/DC superimposed operations

    NARCIS (Netherlands)

    Yan, K.; Yamamoto, T.; Kanazawa, S.; Ohkubo, T.; Nomoto, Y.; Chang, Jen-Shih

    2001-01-01

    In this paper, the effects of the applied voltage modes on the positive corona discharge morphology and NO removal characteristics from air streams are experimentally investigated. By using a DC superimposed high frequency AC power supply (10-60 kHz), a uniform streamer corona can be generated,

  17. Comparison of different undulator schemes with superimposed alternating gradients for the VUV-FEL at the TESLA Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Pflueger, J.; Nikitina, Y.M. [DESY/HASYLAB, Hamburg (Germany)

    1995-12-31

    For the VUV-FEL at the TESLA Test Facility an undulator with a total length of 30 m is needed. In this study three different approaches to realize an undulator with a sinusoidal plus a superimposed quadrupolar field were studied with the 3D code MAFIA.

  18. The carbonaceous matter in the uraniferous dequartzified and albitized leucogranite of Saraya (Senegal): an example of superimposed hydrothermal alterations

    International Nuclear Information System (INIS)

    Mouthier, B.

    1988-01-01

    Two superimposed early hydrothermal alterations have been recognized in the Proterozoic Saraya leucogranite. Successively are described a major dequartzification leading to an episyenite infilled with carbonaceous matter and sulfate during an interruption of the system, succeeded by a mobilization of U and other elements during an albitization. A dolomite filling up followed by a silicopotassic feed-back alteration, close down the system [fr

  19. Augmented vascular smooth muscle cell stiffness and adhesion when hypertension is superimposed on aging.

    Science.gov (United States)

    Sehgel, Nancy L; Sun, Zhe; Hong, Zhongkui; Hunter, William C; Hill, Michael A; Vatner, Dorothy E; Vatner, Stephen F; Meininger, Gerald A

    2015-02-01

    Hypertension and aging are both recognized to increase aortic stiffness, but their interactions are not completely understood. Most previous studies have attributed increased aortic stiffness to changes in extracellular matrix proteins that alter the mechanical properties of the vascular wall. Alternatively, we hypothesized that a significant component of increased vascular stiffness in hypertension is due to changes in the mechanical and adhesive properties of vascular smooth muscle cells, and that aging would augment the contribution from vascular smooth muscle cells when compared with the extracellular matrix. Accordingly, we studied aortic stiffness in young (16-week-old) and old (64-week-old) spontaneously hypertensive rats and Wistar-Kyoto wild-type controls. Systolic and pulse pressures were significantly increased in young spontaneously hypertensive rats when compared with young Wistar-Kyoto rats, and these continued to rise in old spontaneously hypertensive rats when compared with age-matched controls. Excised aortic ring segments exhibited significantly greater elastic moduli in both young and old spontaneously hypertensive rats versus Wistar-Kyoto rats. were isolated from the thoracic aorta, and stiffness and adhesion to fibronectin were measured by atomic force microscopy. Hypertension increased both vascular smooth muscle cell stiffness and vascular smooth muscle cell adhesion, and these increases were both augmented with aging. By contrast, hypertension did not affect histological measures of aortic collagen and elastin, which were predominantly changed by aging. These findings support the concept that stiffness and adhesive properties of vascular smooth muscle cells are novel mechanisms contributing to the increased aortic stiffness occurring with hypertension superimposed on aging. © 2014 American Heart Association, Inc.

  20. Dynamic tensile tests with superimposed ultrasonic oscillations for stainless steel type 321 at room temperature

    International Nuclear Information System (INIS)

    Schinke, B.; Malmberg, T.

    1987-01-01

    In recent years various containment codes for Fast Breeder Reactor accidents have been assessed by comparison with explosion tests in water-filled vessels (COVA experiments). Common to the various codes, a systematic underestimation of the circumferential vessel strains was found. In the COVA tests high frequency pressure oscillations in the ultrasonic range were observed and thus it has been conjectured that the phenomenon of ''acoustic softening'' might be relevant in explaining the discrepancies in the strains. To validate this conjecture a hydro-pneumatic tensile test apparatus was developed which allows dynamic tensile testing at room temperature with and without superimposed ultrasonic oscillations. The dynamic tensile tests on the COVA sheet material (stainless steel AISI 321) without ultrasonic insonation show a linear dependence of the flow stress on the logarithm of the strain rate. The results at low strain rates (10 -3 s -1 ) agree favourably with previous measurements but at high rates (50 s -1 ) at 20% lower flow stress is observed. The dynamic tensile tests with continuous and intermittent insonation show the phenomenon of ''acoustic softening'': The average flow stress is reduced by an amount of about half the oscillating amplitude. At high strain rates the reduction is less. A severe ''acoustic softening'' observed by several authors for various metals at low strain rates was not observed. The experimental results were compared with the theory of the superpositon mechanism assuming a rate-independent elastic-plastic and an elastic-viscoplastic constitutive model. Although the rate-independent model is capable to predict qualitatively some of the observed effects, a better description is obtained with the viscoplastic model. The conclusion is that the ''acoustic softening'' of the COVA material is far too small to explain the discrepancies between measured and computed strains found in the containment code validation studies. (orig.)

  1. The effects of superimposed tilt and lower body negative pressure on anterior and posterior cerebral circulations.

    Science.gov (United States)

    Tymko, Michael M; Rickards, Caroline A; Skow, Rachel J; Ingram-Cotton, Nathan C; Howatt, Michael K; Day, Trevor A

    2016-09-01

    Steady-state tilt has no effect on cerebrovascular reactivity to increases in the partial pressure of end-tidal carbon dioxide (PETCO2). However, the anterior and posterior cerebral circulations may respond differently to a variety of stimuli that alter central blood volume, including lower body negative pressure (LBNP). Little is known about the superimposed effects of head-up tilt (HUT; decreased central blood volume and intracranial pressure) and head-down tilt (HDT; increased central blood volume and intracranial pressure), and LBNP on cerebral blood flow (CBF) responses. We hypothesized that (a) cerebral blood velocity (CBV; an index of CBF) responses during LBNP would not change with HUT and HDT, and (b) CBV in the anterior cerebral circulation would decrease to a greater extent compared to posterior CBV during LBNP when controlling PETCO2 In 13 male participants, we measured CBV in the anterior (middle cerebral artery, MCAv) and posterior (posterior cerebral artery, PCAv) cerebral circulations using transcranial Doppler ultrasound during LBNP stress (-50 mmHg) in three body positions (45°HUT, supine, 45°HDT). PETCO2 was measured continuously and maintained at constant levels during LBNP through coached breathing. Our main findings were that (a) steady-state tilt had no effect on CBV responses during LBNP in both the MCA (P = 0.077) and PCA (P = 0.583), and (b) despite controlling for PETCO2, both the MCAv and PCAv decreased by the same magnitude during LBNP in HUT (P = 0.348), supine (P = 0.694), and HDT (P = 0.407). Here, we demonstrate that there are no differences in anterior and posterior circulations in response to LBNP in different body positions. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  2. Quantum information storage using tunable flux qubits

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Matthias; Brito, Frederico; DiVincenzo, David; Farinelli, Matthew; Keefe, George; Ketchen, Mark; Kumar, Shwetank; Milliken, Frank; Rothwell, Mary Beth; Rozen, Jim; Koch, Roger H, E-mail: msteffe@us.ibm.co [IBM Watson Research Center, Yorktown Heights, NY 10598 (United States)

    2010-02-10

    We present details and results for a superconducting quantum bit (qubit) design in which a tunable flux qubit is coupled strongly to a transmission line. Quantum information storage in the transmission line is demonstrated with a dephasing time of T{sub 2}approx2.5 mus. However, energy lifetimes of the qubit are found to be short (approx10 ns) and not consistent with predictions. Several design and material changes do not affect qubit coherence times. In order to determine the cause of these short coherence times, we fabricated standard flux qubits based on a design which was previously successfully used by others. Initial results show significantly improved coherence times, possibly implicating losses associated with the large size of our qubit. (topical review)

  3. Electromagnetic spatial coherence wavelets

    International Nuclear Information System (INIS)

    Castaneda, R.; Garcia-Sucerquia, J.

    2005-10-01

    The recently introduced concept of spatial coherence wavelets is generalized for describing the propagation of electromagnetic fields in the free space. For this aim, the spatial coherence wavelet tensor is introduced as an elementary amount, in terms of which the formerly known quantities for this domain can be expressed. It allows analyzing the relationship between the spatial coherence properties and the polarization state of the electromagnetic wave. This approach is completely consistent with the recently introduced unified theory of coherence and polarization for random electromagnetic beams, but it provides a further insight about the causal relationship between the polarization states at different planes along the propagation path. (author)

  4. Text Coherence in Translation

    Science.gov (United States)

    Zheng, Yanping

    2009-01-01

    In the thesis a coherent text is defined as a continuity of senses of the outcome of combining concepts and relations into a network composed of knowledge space centered around main topics. And the author maintains that in order to obtain the coherence of a target language text from a source text during the process of translation, a translator can…

  5. Coherent Multistatic ISAR Imaging

    NARCIS (Netherlands)

    Dorp, Ph. van; Otten, M.P.G.; Verzeilberg, J.M.M.

    2012-01-01

    This paper presents methods for Coherent Multistatic Radar Imaging for Non Cooperative Target Recognition (NCTR) with a network of radar sensors. Coherent Multistatic Radar Imaging is based on an extension of existing monostatic ISAR algorithms to the multistatic environment. The paper describes the

  6. VCSEL Based Coherent PONs

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee; Rodes, Roberto; Caballero Jambrina, Antonio

    2014-01-01

    We present a review of research performed in the area of coherent access technologies employing vertical cavity surface emitting lasers (VCSELs). Experimental demonstrations of optical transmission over a passive fiber link with coherent detection using VCSEL local oscillators and directly modula...

  7. Pregnancy Outcomes in Women with Preeclampsia Superimposed on Chronic Hypertension with and without Severe Features.

    Science.gov (United States)

    Moussa, Hind N; Leon, Mateo G; Marti, Ana; Chediak, Alissar; Pedroza, Claudia; Blackwell, Sean C; Sibai, Baha M

    2017-03-01

    Objective  The American Congress of Obstetricians and Gynecologists (ACOG) task force on hypertension in pregnancy introduced a new definition of superimposed preeclampsia (SIP) adding severe features (SF) as new criteria to define severe disease. They also recommended that those with SIP be delivered ≥ 37 weeks, whereas those with SF be delivered ≤ 34 weeks. Our aim was to investigate the validity of this new definition by comparing adverse pregnancy outcomes in SIP with (SIP-SF) and without SF (SIP). Study Design  Women with chronic hypertension (CHTN) enrolled in a multicenter trial were studied. SIP was reclassified according to the new definition to SIP and SIP-SF (persistent systolic blood pressure [BP] > 160 or diastolic BP > 110, platelets  70, creatinine > 1.1, or persistent central nervous system/abdominal symptoms). Composite adverse outcomes including rates of indicated preterm birth, abruptio placentae, postpartum hemorrhage, and maternal death were compared by chi-square. Adjustment was done with a multivariate logistic-regression analysis and all statistical tests were two-sided. Results  A total of 216 women (28%) out of 774 with CHTN developed SIP, 87 (11%) had SIP-SF, and 129 (17%) didn't have SF. Baseline characteristics including maternal age, baseline BP, and assignment to low-dose aspirin were similar between groups. Using univariate analysis, the composite adverse outcome was higher among the SIP-SF group ( p  = 0.04), as well as indicated preterm birth ( p  = 0.02), cesarean section ( p  = 0.02), and SGA ( p  = 0.02). After adjustment, composite adverse outcomes were not significantly different between groups. The rate of SGA, however, was higher among SIP-SF (adjusted odds ratio: 3.12, p  = 0.02). Conclusion  The rate of SIP-SF in this study was 11% of all women with CHTN. Surprisingly, pregnancy outcomes were not significantly different in those with and without SF. We suggest a

  8. Thermodynamic limit for coherence-limited solar power conversion

    Science.gov (United States)

    Mashaal, Heylal; Gordon, Jeffrey M.

    2014-09-01

    The spatial coherence of solar beam radiation is a key constraint in solar rectenna conversion. Here, we present a derivation of the thermodynamic limit for coherence-limited solar power conversion - an expansion of Landsberg's elegant basic bound, originally limited to incoherent converters at maximum flux concentration. First, we generalize Landsberg's work to arbitrary concentration and angular confinement. Then we derive how the values are further lowered for coherence-limited converters. The results do not depend on a particular conversion strategy. As such, they pertain to systems that span geometric to physical optics, as well as classical to quantum physics. Our findings indicate promising potential for solar rectenna conversion.

  9. Lumbosacral multiradiculopathy responsive to antibiotic therapy: description of four patients with lumbar spondylosis and a superimposed Lyme disease.

    Science.gov (United States)

    Luigetti, Marco; Vollaro, Stefano; Corbetto, Marzia; Salomone, Gaetano; Dicuonzo, Giordano; Scoppettuolo, Giancarlo; Di Lazzaro, Vincenzo

    2014-12-01

    Lyme disease is a diffuse zoonosis caused by spirochaetes of the Borrelia burgdorferi species complex. Neurological manifestations of the disease, involving central or peripheral nervous system, are common. This study describes four consecutive patients with an MRI-proven lumbosacral spondylosis, who complained of progressive worsening of symptoms in the last months in which serological evaluation suggested a superimposed B. Burgdorferi infection. Four patients, all from the Lazio region, were admitted to the Department of Neurology. Extensive laboratory studies and clinical, anamnestic and neurophysiological evaluation were performed in all cases. In all cases, anamnesis revealed a previous diagnosis of lumbosacral foraminal stenosis. Clinical and neurophysiological findings were consistent with a lumbosacral multiradiculopathy. Considering serological evaluation suggestive of a superimposed B. burgdorferi infection a proper antibiotic therapy was started. All cases showed a marked improvement of symptoms. Clinicians should be aware that in all cases of lumbosacral multiradiculopathy, even if a mechanical cause is documented, B. burgdorferi may be a simply treatable condition.

  10. Theoretical analysis of turbulent transport through the diffuse boundary layer in the dynamic stabilization of superimposed miscible liquids

    International Nuclear Information System (INIS)

    Gerhauser, H.

    1980-02-01

    Two superimposed miscible liquids are separated by a diffuse boundary layer providing a steady transition of density. If the heavy fluid is on top of the light one, Rayleigh-Taylor-instabilities develop and cause a rapid interchange and eventually an intermixing. This process can be subjected to dynamic stabilization by enforcing vertical oscillations upon the whole system. However, since only part of the unstable mode spectrum is completely stabilized, the remaining weakly unstable modes lead to turbulent transport processes through the boundary layer ('anomalous diffusion'), so that only a quasistationary equilibrium is achieved. In the present paper, previous experimental results on the dynamic stabilization of water superimposed by an aqueous ZnJ-solution are theoretically interpreted, and the observed spatial structure as well as the time development of the density profiles are explained. There exists an analogy between these phenomena and turbulent transport processes in tokamak discharges such as the sawtooth oscillations of internal disruptions. (orig.) [de

  11. Scalable coherent interface

    International Nuclear Information System (INIS)

    Alnaes, K.; Kristiansen, E.H.; Gustavson, D.B.; James, D.V.

    1990-01-01

    The Scalable Coherent Interface (IEEE P1596) is establishing an interface standard for very high performance multiprocessors, supporting a cache-coherent-memory model scalable to systems with up to 64K nodes. This Scalable Coherent Interface (SCI) will supply a peak bandwidth per node of 1 GigaByte/second. The SCI standard should facilitate assembly of processor, memory, I/O and bus bridge cards from multiple vendors into massively parallel systems with throughput far above what is possible today. The SCI standard encompasses two levels of interface, a physical level and a logical level. The physical level specifies electrical, mechanical and thermal characteristics of connectors and cards that meet the standard. The logical level describes the address space, data transfer protocols, cache coherence mechanisms, synchronization primitives and error recovery. In this paper we address logical level issues such as packet formats, packet transmission, transaction handshake, flow control, and cache coherence. 11 refs., 10 figs

  12. Measuring coherence with entanglement concurrence

    Science.gov (United States)

    Qi, Xianfei; Gao, Ting; Yan, Fengli

    2017-07-01

    Quantum coherence is a fundamental manifestation of the quantum superposition principle. Recently, Baumgratz et al (2014 Phys. Rev. Lett. 113 140401) presented a rigorous framework to quantify coherence from the view of theory of physical resource. Here we propose a new valid quantum coherence measure which is a convex roof measure, for a quantum system of arbitrary dimension, essentially using the generalized Gell-Mann matrices. Rigorous proof shows that the proposed coherence measure, coherence concurrence, fulfills all the requirements dictated by the resource theory of quantum coherence measures. Moreover, strong links between the resource frameworks of coherence concurrence and entanglement concurrence is derived, which shows that any degree of coherence with respect to some reference basis can be converted to entanglement via incoherent operations. Our work provides a clear quantitative and operational connection between coherence and entanglement based on two kinds of concurrence. This new coherence measure, coherence concurrence, may also be beneficial to the study of quantum coherence.

  13. Experimental study of coherent radiation in the millimeter-wave region at the KURRI-LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Toshiharu [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.

    1996-07-01

    Coherent radiation, i.e., synchrotron radiation, transition radiation, Cherenkov radiation, or Smith-Purcell radiation emitted by short bunches of electrons has been observed in the millimeter-wave region. Properties of coherent radiation are characterized by the coherence effect and the relativistic one. The intensity of coherent radiation is enormously enhanced by several orders of magnitude in comparison with the incoherent radiation and the flux of radiation concentrates around the direction of the electron beam. Coherent radiation is useful as the intense light source in the millimeter-wave region. (author)

  14. Effects of superimposed hydrostatic pressure on flow and fracture of a Zr-Ti-Ni-Cu-Be bulk amorphous alloy

    International Nuclear Information System (INIS)

    Lowhaphandu, P.; Montgomery, S.L.; Lewandowski, J.J.

    1999-01-01

    Recent successes in producing bulk amorphous alloys have renewed interest in this class of materials. Although amorphous metallic alloys have been shown to exhibit strengths in excess of 2.0 GPa, most of the earlier studies on such materials were conducted on tape or ribbon specimens due to the high cooling rates required to achieve the amorphous structure. The primary purpose of this investigation was to determine the effects of superimposed hydrostatic pressure on the flow and fracture behavior of a Zr-Ti-Ni-Cu-Be bulk metallic glass utilizing procedures successfully utilized on a range of structural materials, as reviewed recently. In general, few studies of this type have been conducted on metallic glasses, although thin ribbons (i.e., 300 microm thick) of a Pd-Cu-Si amorphous material tested with superimposed pressure have been reported previously. In particular, the effects of superimposed hydrostatic pressure over levels ranging from 50 MPa to 575 MPa on the flow/fracture behavior of cylindrical tensile specimens were compared to the flow and fracture behavior of identical materials tested in uniaxial tension and compression. It is shown that changes in stress triaxiality, defined as σ m /bar σ, over the range of -0.33 to 0.33 produced a negligible effect on the fracture stress and fracture strain, while the orientation of the macroscopic fracture plane with respect to the loading axis was significantly affected by changes in σ m /bar σ

  15. Association between delirium superimposed on dementia and mortality in hospitalized older adults: A prospective cohort study.

    Directory of Open Access Journals (Sweden)

    Thiago J Avelino-Silva

    2017-03-01

    Full Text Available Hospitalized older adults with preexisting dementia have increased risk of having delirium, but little is known regarding the effect of delirium superimposed on dementia (DSD on the outcomes of these patients. Our aim was to investigate the association between DSD and hospital mortality and 12-mo mortality in hospitalized older adults.This was a prospective cohort study completed in the geriatric ward of a university hospital in São Paulo, Brazil. We included 1,409 hospitalizations of acutely ill patients aged 60 y and over from January 2009 to June 2015. Main variables and measures included dementia and dementia severity (Informant Questionnaire on Cognitive Decline in the Elderly, Clinical Dementia Rating and delirium (Confusion Assessment Method. Primary outcomes were time to death in the hospital and time to death in 12 mo (for the discharged sample. Comprehensive geriatric assessment was performed at admission, and additional clinical data were documented upon death or discharge. Cases were categorized into four groups (no delirium or dementia, dementia alone, delirium alone, and DSD. The no delirium/dementia group was defined as the referent category for comparisons, and multivariate analyses were performed using Cox proportional hazards models adjusted for possible confounders (sociodemographic information, medical history and physical examination data, functional and nutritional status, polypharmacy, and laboratory covariates. Overall, 61% were women and 39% had dementia, with a mean age of 80 y. Dementia alone was observed in 13% of the cases, with delirium alone in 21% and DSD in 26% of the cases. In-hospital mortality was 8% for patients without delirium or dementia, 12% for patients with dementia alone, 29% for patients with delirium alone, and 32% for DSD patients (Pearson Chi-square = 112, p < 0.001. DSD and delirium alone were independently associated with in-hospital mortality, with respective hazard ratios (HRs of 2.14 (95% CI

  16. Possibility of single biomolecule imaging with coherent amplification of weak scattering x-ray photons.

    Science.gov (United States)

    Shintake, Tsumoru

    2008-10-01

    The number of photons produced by coherent x-ray scattering from a single biomolecule is very small because of its extremely small elastic-scattering cross section and low damage threshold. Even with a high x-ray flux of 3 x 10;{12} photons per 100-nm -diameter spot and an ultrashort pulse of 10 fs driven by a future x-ray free electron laser (x-ray FEL), it has been predicted that only a few 100 photons will be produced from the scattering of a single lysozyme molecule. In observations of scattered x rays on a detector, the transfer of energy from wave to matter is accompanied by the quantization of the photon energy. Unfortunately, x rays have a high photon energy of 12 keV at wavelengths of 1A , which is required for atomic resolution imaging. Therefore, the number of photoionization events is small, which limits the resolution of imaging of a single biomolecule. In this paper, I propose a method: instead of directly observing the photons scattered from the sample, we amplify the scattered waves by superimposing an intense coherent reference pump wave on it and record the resulting interference pattern on a planar x-ray detector. Using a nanosized gold particle as a reference pump wave source, we can collect 10;{4}-10;{5} photons in single shot imaging where the signal from a single biomolecule is amplified and recorded as two-dimensional diffraction intensity data. An iterative phase retrieval technique can be used to recover the phase information and reconstruct the image of the single biomolecule and the gold particle at the same time. In order to precisely reconstruct a faint image of the single biomolecule in Angstrom resolution, whose intensity is much lower than that of the bright gold particle, I propose a technique that combines iterative phase retrieval on the reference pump wave and the digital Fourier transform holography on the sample. By using a large number of holography data, the three-dimensional electron density map can be assembled.

  17. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step...... length, step height, and.flux start level. Filtrating 8 kg/m(3) yeast cell suspensions by a vibrating 0.45 x 10(-6) m pore size microfiltration hollow fiber module, critical fluxes from 5.6 x 10(-6) to 1.2 x 10(-5) m/s have been measured using various step lengths from 300 to 1200 seconds. Thus......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  18. Intracoronary optical coherence tomography

    DEFF Research Database (Denmark)

    Tenekecioglu, Erhan; Albuquerque, Felipe N; Sotomi, Yohei

    2017-01-01

    By providing valuable information about the coronary artery wall and lumen, intravascular imaging may aid in optimizing interventional procedure results and thereby could improve clinical outcomes following percutaneous coronary intervention (PCI). Intravascular optical coherence tomography (OCT...

  19. Coherence in Industrial Transformation

    DEFF Research Database (Denmark)

    Jørgensen, Ulrik; Lauridsen, Erik Hagelskjær

    2003-01-01

    The notion of coherence is used to illustrate the general finding, that the impact of environmental management systems and environmental policy is highly dependent of the context and interrelatedness of the systems, procedures and regimes established in society....

  20. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Fercher, A.F.; Andersen, Peter E.

    2017-01-01

    Optical coherence tomography (OCT) is a technique that is used to peer inside a body noninvasively. Tissue structure defined by tissue absorption and scattering coefficients, and the speed of blood flow, are derived from the characteristics of light remitted by the body. Singly backscattered light...... detected by partial coherence interferometry (PCI) is used to synthesize the tomographic image coded in false colors. A prerequisite of this technique is a low time-coherent but high space-coherent light source, for example, a superluminescent diode or a supercontinuum source. Alternatively, the imaging...... technique can be realized by using ultrafast wavelength scanning light sources. For tissue imaging, the light source wavelengths are restricted to the red and near-infrared (NIR) region from about 600 to 1300 nm, the so-called therapeutic window, where absorption (μa ≈ 0.01 mm−1) is small enough. Transverse...

  1. Coherent imaging at FLASH

    International Nuclear Information System (INIS)

    Chapman, H N; Bajt, S; Duesterer, S; Treusch, R; Barty, A; Benner, W H; Bogan, M J; Frank, M; Hau-Riege, S P; Woods, B W; Boutet, S; Cavalleri, A; Hajdu, J; Iwan, B; Seibert, M M; Timneanu, N; Marchesini, S; Sakdinawat, A; Sokolowski-Tinten, K

    2009-01-01

    We have carried out high-resolution single-pulse coherent diffractive imaging at the FLASH free-electron laser. The intense focused FEL pulse gives a high-resolution low-noise coherent diffraction pattern of an object before that object turns into a plasma and explodes. In particular we are developing imaging of biological specimens beyond conventional radiation damage resolution limits, developing imaging of ultrafast processes, and testing methods to characterize and perform single-particle imaging.

  2. Coupled Qubits for Next Generation Quantum Annealing: Improving Coherence

    Science.gov (United States)

    Weber, Steven; Samach, Gabriel; Hover, David; Rosenberg, Danna; Yoder, Jonilyn; Kim, David K.; Kerman, Andrew; Oliver, William D.

    Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times, limited primarily by the use of large persistent currents. Here, we examine an alternative approach, using flux qubits with smaller persistent currents and longer coherence times. We demonstrate tunable coupling, a basic building-block for quantum annealing, between two such qubits. Furthermore, we characterize qubit coherence as a function of coupler setting and investigate the effect of flux noise in the coupler loop on qubit coherence. Our results provide insight into the available design space for next-generation quantum annealers with improved coherence. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) and by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  3. Image-quality degradation in a turbid medium under partially coherent illumination

    International Nuclear Information System (INIS)

    Zardecki, A.; Gerstl, S.A.W.; Tam, W.G.; Embury, J.F.

    1986-01-01

    The image-quality degradation as a result of propagation through a turbid medium is analyzed within the small-angle approximation to the equation of transfer. By using the well-known correspondence between the radiance distribution and the mutual-coherence function, we formulate a factorization assumption for the mutual coherence in order to restrict the class of radiance distributions in the object plane. Depending on the contrast factor, that is, in general, the class of partially coherent light beams. The general formula for the irradiance distribution in the image plane contains the classic result of Hufnagel and Stanley [J. Opt. Soc. Am. 54, 52 (1964)] as a special case. We study the limits of an infinite lens and a Gaussian aperture and investigate in detail the case of a Gaussian beam with a cosinusoidally superimposed signal. The solution in the form of a multiple-scattering series enables us to discuss the signficance of scattering events of higher order

  4. Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

    Science.gov (United States)

    Kumar, Naveen; Dubey, Ashish; Bahrami, Behzad; Venkatesan, S.; Qiao, Qiquan; Kumar, Mukesh

    2018-04-01

    In this work, the energy and flux of high energetic ions were controlled by RF superimposed DC sputtering process to increase the grain size and suppress grain boundary potential with minimum residual stress in Al doped ZnO (AZO) thin film. AZO thin films were deposited at different RF/(RF + DC) ratios by keeping total power same and were investigated for their electrical, optical, structural and nanoscale grain boundaries potential. All AZO thin film showed high crystallinity and orientation along (002) with peak shift as RF/(RF + DC) ratio increased from 0.0, pure DC, to 1.0, pure RF. This peak shift was correlated with high residual stress in as-grown thin film. AZO thin film grown at mixed RF/(RF + DC) of 0.75 showed high electron mobility, low residual stress and large crystallite size in comparison to other AZO thin films. The nanoscale grain boundary potential was mapped using Kelvin Probe Force Microscopy in all AZO thin film and it was observed that carrier mobility is controlled not only by grains size but also by grain boundary potential. The XPS analysis confirms the variation in oxygen vacancies and zinc interstitials which explain the origin of low grain boundaries potential and high carrier mobility in AZO thin film deposited at 0.75 RF/(RF + DC) ratio. This study proposes a new way to control the grain size and grain boundary potential to further tune the optoelectronic-mechanical properties of AZO thin films for next generation flexible and optoelectronic devices.

  5. Hysteresis Bearingless Slice Motors with Homopolar Flux-biasing.

    Science.gov (United States)

    Noh, Minkyun; Gruber, Wolfgang; Trumper, David L

    2017-10-01

    We present a new concept of bearingless slice motor that levitates and rotates a ring-shaped solid rotor. The rotor is made of a semi-hard magnetic material exhibiting magnetic hysteresis, such as D2 steel. The rotor is radially biased with a homopolar permanent-magnetic flux, on which the stator can superimpose 2-pole flux to generate suspension forces. By regulating the suspension forces based on position feedback, the two radial rotor degrees of freedom are actively stabilized. The two tilting degrees of freedom and the axial translation are passively stable due to the reluctance forces from the bias flux. In addition, the stator can generate a torque by superimposing 6- pole rotating flux, which drags the rotor via hysteresis coupling. This 6-pole flux does not generate radial forces in conjunction with the homopolar flux or 2-pole flux, and therefore the suspension force generation is in principle decoupled from the driving torque generation. We have developed a prototype system as a proof of concept. The stator has twelve teeth, each of which has a single phase winding that is individually driven by a linear transconductance power amplifier. The system has four reflective-type optical sensors to differentially measure the two radial degrees of freedom of the rotor. The suspension control loop is implemented such that the phase margin is 25 degrees at the cross-over frequency of 110 Hz. The prototype system can levitate the rotor and drive it up to about 1730 rpm. The maximum driving torque is about 2.7 mNm.

  6. Coupling nitrogen-vacancy centers in diamond to superconducting flux qubits

    DEFF Research Database (Denmark)

    Marcos, D.; Wubs, Martijn; Taylor, J.M.

    2010-01-01

    We propose a method to achieve coherent coupling between nitrogen-vacancy (NV) centers in diamond and superconducting (SC) flux qubits. The resulting coupling can be used to create a coherent interaction between the spin states of distant NV centers mediated by the flux qubit. Furthermore......, the magnetic coupling can be used to achieve a coherent transfer of quantum information between the flux qubit and an ensemble of NV centers. This enables a long-term memory for a SC quantum processor and possibly an interface between SC qubits and light....

  7. Dependence of the frequency spectrum of small amplitude vibrations superimposed on finite deformations of a nonlinear, cylindrical elastic body on residual stress

    KAUST Repository

    Gorb, Yuliya; Walton, Jay R.

    2010-01-01

    We model and analyze the response of nonlinear, residually stressed elastic bodies subjected to small amplitude vibrations superimposed upon large deformations. The problem derives from modeling the use of intravascular ultrasound (IVUS) imaging

  8. Stimulated coherent transition radiation

    International Nuclear Information System (INIS)

    Hung-chi Lihn.

    1996-03-01

    Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed

  9. Advances in the Surface Renewal Flux Measurement Method

    Science.gov (United States)

    Shapland, T. M.; McElrone, A.; Paw U, K. T.; Snyder, R. L.

    2011-12-01

    The measurement of ecosystem-scale energy and mass fluxes between the planetary surface and the atmosphere is crucial for understanding geophysical processes. Surface renewal is a flux measurement technique based on analyzing the turbulent coherent structures that interact with the surface. It is a less expensive technique because it does not require fast-response velocity measurements, but only a fast-response scalar measurement. It is therefore also a useful tool for the study of the global cycling of trace gases. Currently, surface renewal requires calibration against another flux measurement technique, such as eddy covariance, to account for the linear bias of its measurements. We present two advances in the surface renewal theory and methodology that bring the technique closer to becoming a fully independent flux measurement method. The first advance develops the theory of turbulent coherent structure transport associated with the different scales of coherent structures. A novel method was developed for identifying the scalar change rate within structures at different scales. Our results suggest that for canopies less than one meter in height, the second smallest coherent structure scale dominates the energy and mass flux process. Using the method for resolving the scalar exchange rate of the second smallest coherent structure scale, calibration is unnecessary for surface renewal measurements over short canopies. This study forms the foundation for analysis over more complex surfaces. The second advance is a sensor frequency response correction for measuring the sensible heat flux via surface renewal. Inexpensive fine-wire thermocouples are frequently used to record high frequency temperature data in the surface renewal technique. The sensible heat flux is used in conjunction with net radiation and ground heat flux measurements to determine the latent heat flux as the energy balance residual. The robust thermocouples commonly used in field experiments

  10. SAR image effects on coherence and coherence estimation.

    Energy Technology Data Exchange (ETDEWEB)

    Bickel, Douglas Lloyd

    2014-01-01

    Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

  11. Synchronized moving aperture radiation therapy (SMART): superimposing tumor motion on IMRT MLC leaf sequences under realistic delivery conditions

    International Nuclear Information System (INIS)

    Xu Jun; Papanikolaou, Nikos; Shi Chengyu; Jiang, Steve B

    2009-01-01

    Synchronized moving aperture radiation therapy (SMART) has been proposed to account for tumor motions during radiotherapy in prior work. The basic idea of SMART is to synchronize the moving radiation beam aperture formed by a dynamic multileaf collimator (DMLC) with the tumor motion induced by respiration. In this paper, a two-dimensional (2D) superimposing leaf sequencing method is presented for SMART. A leaf sequence optimization strategy was generated to assure the SMART delivery under realistic delivery conditions. The study of delivery performance using the Varian LINAC and the Millennium DMLC showed that clinical factors such as collimator angle, dose rate, initial phase and machine tolerance affect the delivery accuracy and efficiency. An in-house leaf sequencing software was developed to implement the 2D superimposing leaf sequencing method and optimize the motion-corrected leaf sequence under realistic clinical conditions. The analysis of dynamic log (Dynalog) files showed that optimization of the leaf sequence for various clinical factors can avoid beam hold-offs which break the synchronization of SMART and fail the SMART dose delivery. Through comparison between the simulated delivered fluence map and the planed fluence map, it was shown that the motion-corrected leaf sequence can greatly reduce the dose error.

  12. Accuracy of biopsy needle navigation using the Medarpa system - computed tomography reality superimposed on the site of intervention

    International Nuclear Information System (INIS)

    Khan, M. Fawad; Maataoui, Adel; Gurung, Jessen; Schiemann, Mirko; Vogl, Thomas J.; Dogan, Selami; Ackermann, Hanns; Wesarg, Stefan; Sakas, Georgios

    2005-01-01

    The aim of this work was to determine the accuracy of a new navigational system, Medarpa, with a transparent display superimposing computed tomography (CT) reality on the site of intervention. Medarpa uses an optical and an electromagnetic tracking system which allows tracking of instruments, the radiologist and the transparent display. The display superimposes a CT view of a phantom chest on a phantom chest model, in real time. In group A, needle positioning was performed using the Medarpa system. Three targets (diameter 1.5 mm) located inside the phantom were punctured. In group B, the same targets were used to perform standard CT-guided puncturing using the single-slice technique. The same needles were used in both groups (15 G, 15 cm). A total of 42 punctures were performed in each group. Post puncture, CT scans were made to verify needle tip positions. The mean deviation from the needle tip to the targets was 6.65±1.61 mm for group A (range 3.54-9.51 mm) and 7.05±1.33 mm for group B (range 4.10-9.45 mm). No significant difference was found between group A and group B for any target (p>0.05). No significant difference was found between the targets of the same group (p>0.05). The accuracy in needle puncturing using the augmented reality system, Medarpa, matches the accuracy achieved by CT-guided puncturing technique. (orig.)

  13. Early capillary flux homogenization in response to neural activation.

    Science.gov (United States)

    Lee, Jonghwan; Wu, Weicheng; Boas, David A

    2016-02-01

    This Brief Communication reports early homogenization of capillary network flow during somatosensory activation in the rat cerebral cortex. We used optical coherence tomography and statistical intensity variation analysis for tracing changes in the red blood cell flux over hundreds of capillaries nearly at the same time with 1-s resolution. We observed that while the mean capillary flux exhibited a typical increase during activation, the standard deviation of the capillary flux exhibited an early decrease that happened before the mean flux increase. This network-level data is consistent with the theoretical hypothesis that capillary flow homogenizes during activation to improve oxygen delivery. © The Author(s) 2015.

  14. COHERENT Experiment: current status

    International Nuclear Information System (INIS)

    Akimov, D; Belov, V; Bolozdynya, A; Burenkov, A; Albert, J B; Del Valle Coello, M; D’Onofrio, M; Awe, C; Barbeau, P S; Cervantes, M; Becker, B; Cabrera-Palmer, B; Collar, J I; Cooper, R J; Cooper, R L; Cuesta, C; Detwiler, J; Eberhardt, A; Dean, D; Dolgolenko, A G

    2017-01-01

    The COHERENT Collaboration is realizing a long term neutrino physics research program. The main goals of the program are to detect and study elastic neutrino-nucleus scattering (CEνNS). This process is predicted by Standard Model but it has never been observed experimentally because of the very low energy of the recoil nucleus. COHERENT is using different detector technologies: CsI[Na] and NaI scintillator crystals, a single-phase liquid Ar and a Ge detectors. The placement of all the detector setups is in the basement of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The current status of the COHERENT experimental program is presented. (paper)

  15. Dynamic coherent backscattering mirror

    Energy Technology Data Exchange (ETDEWEB)

    Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)

    2016-02-15

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.

  16. Coherence enhanced quantum metrology in a nonequilibrium optical molecule

    Science.gov (United States)

    Wang, Zhihai; Wu, Wei; Cui, Guodong; Wang, Jin

    2018-03-01

    We explore the quantum metrology in an optical molecular system coupled to two environments with different temperatures, using a quantum master equation beyond secular approximation. We discover that the steady-state coherence originating from and sustained by the nonequilibrium condition can enhance quantum metrology. We also study the quantitative measures of the nonequilibrium condition in terms of the curl flux, heat current and entropy production at the steady state. They are found to grow with temperature difference. However, an apparent paradox arises considering the contrary behaviors of the steady-state coherence and the nonequilibrium measures in relation to the inter-cavity coupling strength. This paradox is resolved by decomposing the heat current into a population part and a coherence part. Only the latter, the coherence part of the heat current, is tightly connected to the steady-state coherence and behaves similarly with respect to the inter-cavity coupling strength. Interestingly, the coherence part of the heat current flows from the low-temperature reservoir to the high-temperature reservoir, opposite to the direction of the population heat current. Our work offers a viable way to enhance quantum metrology for open quantum systems through steady-state coherence sustained by the nonequilibrium condition, which can be controlled and manipulated to maximize its utility. The potential applications go beyond quantum metrology and extend to areas such as device designing, quantum computation and quantum technology in general.

  17. Maintaining Web Cache Coherency

    Directory of Open Access Journals (Sweden)

    2000-01-01

    Full Text Available Document coherency is a challenging problem for Web caching. Once the documents are cached throughout the Internet, it is often difficult to keep them coherent with the origin document without generating a new traffic that could increase the traffic on the international backbone and overload the popular servers. Several solutions have been proposed to solve this problem, among them two categories have been widely discussed: the strong document coherency and the weak document coherency. The cost and the efficiency of the two categories are still a controversial issue, while in some studies the strong coherency is far too expensive to be used in the Web context, in other studies it could be maintained at a low cost. The accuracy of these analysis is depending very much on how the document updating process is approximated. In this study, we compare some of the coherence methods proposed for Web caching. Among other points, we study the side effects of these methods on the Internet traffic. The ultimate goal is to study the cache behavior under several conditions, which will cover some of the factors that play an important role in the Web cache performance evaluation and quantify their impact on the simulation accuracy. The results presented in this study show indeed some differences in the outcome of the simulation of a Web cache depending on the workload being used, and the probability distribution used to approximate updates on the cached documents. Each experiment shows two case studies that outline the impact of the considered parameter on the performance of the cache.

  18. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Mogensen, Mette; Themstrup, Lotte; Banzhaf, Christina

    2014-01-01

    Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described as the o......Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described...

  19. Coherent light microscopy

    CERN Document Server

    Ferraro, Pietro; Zalevsky, Zeev

    2011-01-01

    This book deals with the latest achievements in the field of optical coherent microscopy. While many other books exist on microscopy and imaging, this book provides a unique resource dedicated solely to this subject. Similarly, many books describe applications of holography, interferometry and speckle to metrology but do not focus on their use for microscopy. The coherent light microscopy reference provided here does not focus on the experimental mechanics of such techniques but instead is meant to provide a users manual to illustrate the strengths and capabilities of developing techniques. Th

  20. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten

    2016-01-01

    Background During the past decade, politicians and healthcare providers have strived to create a coherent healthcare system across primary and secondary healthcare sectors in Denmark. Nevertheless, elderly patients with chronic diseases (EPCD) continue to report experiences of poor-quality care a...

  1. Coherence in quantum estimation

    Science.gov (United States)

    Giorda, Paolo; Allegra, Michele

    2018-01-01

    The geometry of quantum states provides a unifying framework for estimation processes based on quantum probes, and it establishes the ultimate bounds of the achievable precision. We show a relation between the statistical distance between infinitesimally close quantum states and the second order variation of the coherence of the optimal measurement basis with respect to the state of the probe. In quantum phase estimation protocols, this leads to propose coherence as the relevant resource that one has to engineer and control to optimize the estimation precision. Furthermore, the main object of the theory i.e. the symmetric logarithmic derivative, in many cases allows one to identify a proper factorization of the whole Hilbert space in two subsystems. The factorization allows one to discuss the role of coherence versus correlations in estimation protocols; to show how certain estimation processes can be completely or effectively described within a single-qubit subsystem; and to derive lower bounds for the scaling of the estimation precision with the number of probes used. We illustrate how the framework works for both noiseless and noisy estimation procedures, in particular those based on multi-qubit GHZ-states. Finally we succinctly analyze estimation protocols based on zero-temperature critical behavior. We identify the coherence that is at the heart of their efficiency, and we show how it exhibits the non-analyticities and scaling behavior proper of a large class of quantum phase transitions.

  2. Coherence Multiplex System Topologies

    NARCIS (Netherlands)

    Meijerink, Arjan; Taniman, R.O.; Heideman, G.H.L.M.; van Etten, Wim

    2007-01-01

    Coherence multiplexing is a potentially inexpensive form of optical code-division multiple access, which is particularly suitable for short-range applications with moderate bandwidth requirements, such as access networks, LANs, or interconnects. Various topologies are known for constructing an

  3. Coherent synchrotron radiation

    International Nuclear Information System (INIS)

    Agoh, Tomonori

    2006-01-01

    This article presents basic properties of coherent synchrotron radiation (CSR) with numerical examples and introduces the reader to important aspects of CSR in future accelerators with short bunches. We show interesting features of the single bunch instability due to CSR in storage rings and discuss the longitudinal CSR field via the impedance representation. (author)

  4. Interference due to coherence swapping

    Indian Academy of Sciences (India)

    particle is, its interaction with the beam splitter does not reveal this information .... If one shines a strong linearly polarised monochromatic laser beam, or a quasi .... to be a hindrance to coherence, can be suitably designed to create coherence.

  5. Coherent states in quantum mechanics

    International Nuclear Information System (INIS)

    Rodrigues, R. de Lima; Fernandes Junior, Damasio; Batista, Sheyla Marques

    2001-12-01

    We present a review work on the coherent states is non-relativistic quantum mechanics analysing the quantum oscillators in the coherent states. The coherent states obtained via a displacement operator that act on the wave function of ground state of the oscillator and the connection with Quantum Optics which were implemented by Glauber have also been considered. A possible generalization to the construction of new coherent states it is point out. (author)

  6. Coherent states in quantum mechanics

    CERN Document Server

    Rodrigues, R D L; Fernandes, D

    2001-01-01

    We present a review work on the coherent states is non-relativistic quantum mechanics analysing the quantum oscillators in the coherent states. The coherent states obtained via a displacement operator that act on the wave function of ground state of the oscillator and the connection with Quantum Optics which were implemented by Glauber have also been considered. A possible generalization to the construction of new coherent states it is point out.

  7. Does a global budget superimposed on fee-for-service payments mitigate hospitals' medical claims in Taiwan?

    Science.gov (United States)

    Hsu, Pi-Fem

    2014-12-01

    Taiwan's global budgeting for hospital health care, in comparison to other countries, assigns a regional budget cap for hospitals' medical benefits claimed on the basis of fee-for-service (FFS) payments. This study uses a stays-hospitals-years database comprising acute myocardial infarction inpatients to examine whether the reimbursement policy mitigates the medical benefits claimed to a third-payer party during 2000-2008. The estimated results of a nested random-effects model showed that hospitals attempted to increase their medical benefit claims under the influence of initial implementation of global budgeting. The magnitudes of hospitals' responses to global budgeting were significantly attributed to hospital ownership, accreditation status, and market competitiveness of a region. The results imply that the regional budget cap superimposed on FFS payments provides only blunt incentive to the hospitals to cooperate to contain medical resource utilization, unless a monitoring mechanism attached with the payment system.

  8. Superimposing various biophysical and social scales in a rapidly changing rural area (SW Niger)

    Science.gov (United States)

    Leduc, Christian; Massuel, Sylvain; Favreau, Guillaume; Cappelaere, Bernard; Leblanc, Marc; Bachir, Salifou; Ousmane, Boureïma

    2014-05-01

    transboundary aquifer that extends far beyond the study area, over about 150 000 km2. It is also heterogeneous. Like surface flows, but at a different scale, groundwater flows are marked by a strong endorheism. For example the Dantiandou closed piezometric depression extends over about approximately 5000 km2. These natural closed depressions are explained only by evapotranspiration uptake, weak in absolute terms (a few mm.a-1) but with a very high impact on hydrodynamics because of poor permeability and porosity. Both density of observations and hydraulic continuity of the CT3 aquifer give a fine idea of groundwater changes in the whole area. Human activities, continuously adapting in this poor rural area, add another complexity to the hydrological diversity in surface and ground water. The replacement of the natural vegetation with millet fields and fallow increased the surface runoff, and consequently water accumulation in temporary pools and then CT3 recharge. In the SE part of the study area, the water table has risen up to outcropping in the lowest valley bottoms. These new permanent ponds reflect groundwater while temporary ponds still reflect surface dynamics. This new component of the hydrological landscape induces several consequences, in physical and human dimensions. Evaporation strongly affects the permanent water and increases its salinity while the natural mineralization of groundwater is very low. The easier access to water resources allows a significant development of local gardening, which modifies the social functioning of villages (e.g. land rights between villages and within a village, diversification of crops and sources of income, new sales channels). Different physically based models (for surface and ground water) were built, with a significant discrepancy between their respective quantification of water flows at the region scale. Extrapolation of surface fluxes from the few instrumented catchments to a much larger mosaic of non-instrumented catchments is

  9. Coherent hybrid electromagnetic field imaging

    Science.gov (United States)

    Cooke, Bradly J [Jemez Springs, NM; Guenther, David C [Los Alamos, NM

    2008-08-26

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  10. Magnetic-flux pump

    Science.gov (United States)

    Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

    1966-01-01

    A magnetic flux pump is described for increasing the intensity of a magnetic field by transferring flux from one location to the magnetic field. The device includes a pair of communicating cavities formed in a block of superconducting material, and a piston for displacing the trapped magnetic flux into the secondary cavity producing a field having an intense flux density.

  11. Radon flux measurement methodologies

    International Nuclear Information System (INIS)

    Nielson, K.K.; Rogers, V.C.

    1984-01-01

    Five methods for measuring radon fluxes are evaluated: the accumulator can, a small charcoal sampler, a large-area charcoal sampler, the ''Big Louie'' charcoal sampler, and the charcoal tent sampler. An experimental comparison of the five flux measurement techniques was also conducted. Excellent agreement was obtained between the measured radon fluxes and fluxes predicted from radium and emanation measurements

  12. Coherent hard x-ray focusing optics and applications

    Energy Technology Data Exchange (ETDEWEB)

    Yun, W.B.; Viccaro, P.J.; Chrzas, J.; Lai, B.

    1991-01-01

    Coherent hard x-ray beams with a flux exceeding 10{sup 9} photons/second with a bandwidth of 0.1% will be provided by the undulator at the third generation synchrotron radiation sources such as APS, ESRF, and Spring-8. The availability of such high flux coherent x-ray beams offers excellent opportunities for extending the coherence-based techniques developed in the visible and soft x-ray part of the electromagnetic spectrum to the hard x-rays. These x-ray techniques (e.g., diffraction limited microfocusing, holography, interferometry, phase contrast imaging and signal enhancement), may offer substantial advantages over non-coherence-based x-ray techniques currently used. For example, the signal enhancement technique may be used to enhance an anomalous x-ray or magnetic x-ray scattering signal by several orders of magnitude. Coherent x-rays can be focused to a very small (diffraction-limited) spot size, thus allowing high spatial resolution microprobes to be constructed. The paper will discuss the feasibility of the extension of some coherence-based techniques to the hard x-ray range and the significant progress that has been made in the development of diffraction-limited focusing optics. Specific experimental results for a transmission Fresnel phase zone plate that can focus 8.2 keV x-rays to a spot size of about 2 microns will be briefly discussed. The comparison of measured focusing efficiency of the zone plate with that calculated will be made. Some specific applications of zone plates as coherent x-ray optics will be discussed. 17 refs., 4 figs.

  13. Optical Coherence and Quantum Optics

    CERN Document Server

    Mandel, Leonard

    1995-01-01

    This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topi

  14. Coherent imaging using SACLA

    International Nuclear Information System (INIS)

    Nishino, Yoshinori; Kimura, Takashi; Suzuki, Akihiro; Joti, Yasumasa; Bessho, Yoshitaka

    2017-01-01

    X-ray free-electron lasers (XFELs) with femtosecond pulse duration offer an innovative solution to transcend the spatial resolution limitation in conventional X-ray imaging for biological samples and soft matters by clearing up the radiation damage problem using the “diffraction-before-destruction” strategy. Building on this strategy, the authors are developing a method to image solution sample under controlled environment, pulsed coherent X-ray solution scattering (PCXSS), using XFELs and phase retrieval algorithms in coherent diffractive imaging (CDI). This article describes the basics of PCXSS and examples of PCXSS measurement, for a living cell and self-assemblies of gold nanoparticles, performed by the authors using SACLA. An attempt toward the industrial application of PCXSS is also described. (author)

  15. Coherent dynamics in semiconductors

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    1998-01-01

    enhanced in quantum confined lower-dimensional systems, where exciton and biexciton effects dominate the spectra even at room temperature. The coherent dynamics of excitons are at modest densities well described by the optical Bloch equations and a number of the dynamical effects known from atomic......Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  16. Generalized hypergeometric coherent states

    International Nuclear Information System (INIS)

    Appl, Thomas; Schiller, Diethard H

    2004-01-01

    We introduce a large class of holomorphic quantum states by choosing their normalization functions to be given by generalized hypergeometric functions. We call them generalized hypergeometric states in general, and generalized hypergeometric coherent states in particular, if they allow a resolution of unity. Depending on the domain of convergence of the generalized hypergeometric functions, we distinguish generalized hypergeometric states on the plane, the open unit disc and the unit circle. All states are eigenstates of suitably defined lowering operators. We then study their photon number statistics and phase properties as revealed by the Husimi and Pegg-Barnett phase distributions. On the basis of the generalized hypergeometric coherent states we introduce new analytic representations of arbitrary quantum states in Bargmann and Hardy spaces as well as generalized hypergeometric Husimi distributions and corresponding phase distributions

  17. Updated Magmatic Flux Rate Estimates for the Hawaii Plume

    Science.gov (United States)

    Wessel, P.

    2013-12-01

    Several studies have estimated the magmatic flux rate along the Hawaiian-Emperor Chain using a variety of methods and arriving at different results. These flux rate estimates have weaknesses because of incomplete data sets and different modeling assumptions, especially for the youngest portion of the chain (little or no quantification of error estimates for the inferred melt flux, making an assessment problematic. Here we re-evaluate the melt flux for the Hawaii plume with the latest gridded data sets (SRTM30+ and FAA 21.1) using several methods, including the optimal robust separator (ORS) and directional median filtering techniques (DiM). We also compute realistic confidence limits on the results. In particular, the DiM technique was specifically developed to aid in the estimation of surface loads that are superimposed on wider bathymetric swells and it provides error estimates on the optimal residuals. Confidence bounds are assigned separately for the estimated surface load (obtained from the ORS regional/residual separation techniques) and the inferred subsurface volume (from gravity-constrained isostasy and plate flexure optimizations). These new and robust estimates will allow us to assess which secondary features in the resulting melt flux curve are significant and should be incorporated when correlating melt flux variations with other geophysical and geochemical observations.

  18. Quantum coherence: Reciprocity and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Allahabad-211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India)

    2017-03-18

    Quantum coherence is the outcome of the superposition principle. Recently, it has been theorized as a quantum resource, and is the premise of quantum correlations in multipartite systems. It is therefore interesting to study the coherence content and its distribution in a multipartite quantum system. In this work, we show analytically as well as numerically the reciprocity between coherence and mixedness of a quantum state. We find that this trade-off is a general feature in the sense that it is true for large spectra of measures of coherence and of mixedness. We also study the distribution of coherence in multipartite systems by looking at monogamy-type relation–which we refer to as additivity relation–between coherences of different parts of the system. We show that for the Dicke states, while the normalized measures of coherence violate the additivity relation, the unnormalized ones satisfy the same. - Highlights: • Quantum coherence. • Reciprocity between quantum coherence and mixedness. • Distribution of quantum coherence in multipartite quantum systems. • Additivity relation for distribution of quantum coherence in Dicke and “X” states.

  19. On coherent states

    International Nuclear Information System (INIS)

    Polubarinov, I.V.

    1975-01-01

    A definition of the coherent state representation is given in this paper. In the representation quantum theory equations take the form of classical field theory equations (with causality inherent to the latter) not only in simple cases (free field and interactions with an external current or field), but also in the general case of closed systems of interacting fields. And, conversely, a classical field theory can be transformed into a form of a quantum one

  20. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten

    2016-01-01

    During the past decade, politicians and health care providers have strived to create a coherent health care system across primary and secondary health care systems in Denmark. Nevertheless, elderly patients with chronic diseases (EPCD) continue to report experiences of poor-quality care and lack ...... both nationally and internationally in preparation of health agreements, implementation of new collaboration forms among health care providers, and in improvement of delegation and transfer of information and assignments across sectors in health care....

  1. Spectral coherence in windturbine wakes

    Energy Technology Data Exchange (ETDEWEB)

    Hojstrup, J. [Riso National Lab., Roskilde (Denmark)

    1996-12-31

    This paper describes an experiment at a Danish wind farm to investigate the lateral and vertical coherences in the nonequilibrium turbulence of a wind turbine wake. Two meteorological masts were instrumented for measuring profiles of mean speed, turbulence, and temperature. Results are provided graphically for turbulence intensities, velocity spectra, lateral coherence, and vertical coherence. The turbulence was somewhat influenced by the wake, or possibly from aggregated wakes further upstream, even at 14.5 diameters. Lateral coherence (separation 5m) seemed to be unaffected by the wake at 7.5 diameters, but the flow was less coherent in the near wake. The wake appeared to have little influence on vertical coherence (separation 13m). Simple, conventional models for coherence appeared to be adequate descriptions for wake turbulence except for the near wake situation. 3 refs., 7 figs., 1 tab.

  2. Coherent laser vision system

    International Nuclear Information System (INIS)

    Sebastion, R.L.

    1995-01-01

    The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system

  3. Collision-induced coherence

    International Nuclear Information System (INIS)

    Bloembergen, N.

    1985-01-01

    Collision-induced coherence is based on the elimination of phase correlations between coherent Feynman-type pathways which happen to interfere destructively in the absence of damping for certain nonlinear processes. One consequence is the appearance of the extra resonances in four-wave light mixing experiments, for which the intensity increases with increasing buffer gas pressure. These resonances may occur between a pair of initially unpopulated excited states, or between a pair of initially equally populated ground states. The pair of levels may be Zeeman substrates which became degenerate in zero magnetic field. The resulting collision-enhanced Hanle resonances can lead to very sharp variations in the four-wave light mixing signal as the external magnetic field passes through zero. The theoretical description in terms of a coherence grating between Zeeman substrates is equivalent to a description in terms of a spin polarization grating obtained by collision-enhanced transverse optical pumping. The axis of quantization in the former case is taken perpendicular to the direction of the light beams; in the latter case is taken parallel to this direction

  4. Coherent laser vision system

    Energy Technology Data Exchange (ETDEWEB)

    Sebastion, R.L. [Coleman Research Corp., Springfield, VA (United States)

    1995-10-01

    The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  5. Coherent electron cooling

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  6. Coherent radiation from pulsars

    International Nuclear Information System (INIS)

    Cox, J.L. Jr.

    1979-01-01

    Interaction between a relativistic electrom stream and a plasma under conditions believed to exist in pulsar magnetospheres is shown to result in the simultaneous emission of coherent curvature radiation at radio wavelengths and incoherent curvature radiation at X-ray wavelengths from the same spatial volume. It is found that such a stream can propagate through a plasma parallel to a very strong magnetic field only if its length is less than a critical length L/sub asterisk/ic. Charge induced in the plasma by the stream co-moves with the stream and has the same limitation in longitudinal extent. The resultant charge bunching is sufficient to cause the relatively low energy plasma particles to radiate at radio wavelengths coherently while the relatively high energy stream particles radiate at X-ray wavelengths incoherently as the stream-plasma system moves along curved magnetic field lines. The effective number of coherently radiating particles per bunch is estimated to be approx.10 14 --10 15 for a tupical pulsar

  7. Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system.

    Science.gov (United States)

    Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

    2007-02-01

    We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

  8. Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system

    Science.gov (United States)

    Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

    2007-02-01

    We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

  9. Cyclic steps and superimposed antidune deposits: important elements of coarse-grained deepwater channel-levée complexes

    Science.gov (United States)

    Lang, Joerg; Brandes, Christian; Winsemann, Jutta

    2017-04-01

    The facies distribution and architecture of submarine fans can be strongly impacted by erosion and deposition by supercritical density flows. We present field examples from the Sandino Forearc Basin (southern Central America), where cyclic-step and antidune deposits represent important sedimentary facies of coarse-grained channel-levée complexes. These bedforms occur in all sub-environments of the depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. Large-scale scours (18 to 29 m deep, 18 to 25 m wide, 60 to >120 m long) with an amalgamated infill, comprising massive, normally coarse-tail graded or spaced subhorizontally stratified conglomerates and pebbly sandstones, are interpreted as deposits of the hydraulic-jump zone of cyclic steps. These cyclic steps probably formed during avulsion, when high-density flows were routed into the evolving channel. The large-scale scour fills can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump deposits. Channel fills include repetitive successions deposited by cyclic steps with superimposed antidunes. The hydraulic-jump zone of cyclic-step deposits comprises regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m wide), which are infilled by intraclast-rich conglomerates or pebbly sandstones and display normal coarse-tail grading or backsets. Laterally and vertically these deposits are associated with subhorizontally stratified, low-angle cross-stratified or sinusoidal stratified pebbly sandstones and sandstones (wavelength 0.5 to 18 m), interpreted as representing antidune deposits formed on the stoss-side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called crudely or spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation

  10. High-speed optical coherence tomography by circular interferometric ranging

    Science.gov (United States)

    Siddiqui, Meena; Nam, Ahhyun S.; Tozburun, Serhat; Lippok, Norman; Blatter, Cedric; Vakoc, Benjamin J.

    2018-02-01

    Existing three-dimensional optical imaging methods excel in controlled environments, but are difficult to deploy over large, irregular and dynamic fields. This means that they can be ill-suited for use in areas such as material inspection and medicine. To better address these applications, we developed methods in optical coherence tomography to efficiently interrogate sparse scattering fields, that is, those in which most locations (voxels) do not generate meaningful signal. Frequency comb sources are used to superimpose reflected signals from equispaced locations through optical subsampling. This results in circular ranging, and reduces the number of measurements required to interrogate large volumetric fields. As a result, signal acquisition barriers that have limited speed and field in optical coherence tomography are avoided. With a new ultrafast, time-stretched frequency comb laser design operating with 7.6 MHz to 18.9 MHz repetition rates, we achieved imaging of multi-cm3 fields at up to 7.5 volumes per second.

  11. Intrinsic pinning in superconductors with extremely small coherence lengths

    International Nuclear Information System (INIS)

    Schimmele, L.; Kronmueller, H.; Teichler, H.

    1988-01-01

    By means of a Ginsburg-Landau-type theory which takes into account the discrete lattice structure the variation of the energy ('Peierls potential') of an isolated flux line is calculated when shifted relatively to the crystal lattice. In particular, a primitive cubic lattice is considered with a straight flux line, aligned parallel to a cubic axis. The resulting Peierls potential may lead to intrinsic pinning if the coherence length is smaller than about two nearest neighbour distances. The coherence lengths at low temperatures determined for the recently discovered high T c superconductors of the YBa 2 Cu 3 O 7 class come very close to this value so that intrinsic pinning might possibly be relevant for these superconductors. (author)

  12. Optimization of a coherent soft x-ray beamline for coherent scattering experiments at NSLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro D.; Chubar, O.; Kaznatcheev, K.; Reininger, R.; Sanchez-Hanke, C.; Wang, S.

    2011-08-21

    The coherent soft x-ray and full polarization control (CSX) beamline at the National Synchrotron Light Source - II (NSLS-II) will deliver 1013 coherent photons per second in the energy range of 0.2-2 keV with a resolving power of 2000. The source, a dual elliptically polarizing undulator (EPU), and beamline optics should be optimized to deliver the highest possible coherent flux in a 10-30 {micro}m spot for use in coherent scattering experiments. Using the computer code Synchrotron Radiation Workshop (SRW), we simulate the photon source and focusing optics in order to investigate the conditions which provide the highest usable coherent intensity on the sample. In particular, we find that an intermediate phasing magnet is needed to correct for the relative phase between the two EPUs and that the optimum phase setting produces a spectrum in which the desired wavelength is slightly red-shifted thus requiring a larger aperture than originally anticipated. This setting is distinct from that which produces an on-axis spectrum similar to a single long undulator. Furthermore, partial coherence calculations, utilizing a multiple electron approach, indicate that a high degree of spatial coherence is still obtained at the sample location when such an aperture is used. The aperture size which maximizes the signal-to-noise ratio of a double-slit experiment is explored. This combination of high coherence and intensity is ideally suited for x-ray ptychography experiments which reconstruct the scattering density from micro-diffraction patterns. This technique is briefly reviewed and the effects on the image quality of proximity to the beamline focus are explored.

  13. Clustering of Emerging Flux

    Science.gov (United States)

    Ruzmaikin, A.

    1997-01-01

    Observations show that newly emerging flux tends to appear on the Solar surface at sites where there is flux already. This results in clustering of solar activity. Standard dynamo theories do not predict this effect.

  14. Partially coherent isodiffracting pulsed beams

    Science.gov (United States)

    Koivurova, Matias; Ding, Chaoliang; Turunen, Jari; Pan, Liuzhan

    2018-02-01

    We investigate a class of isodiffracting pulsed beams, which are superpositions of transverse modes supported by spherical-mirror laser resonators. By employing modal weights that, for stationary light, produce a Gaussian Schell-model beam, we extend this standard model to pulsed beams. We first construct the two-frequency cross-spectral density function that characterizes the spatial coherence in the space-frequency domain. By assuming a power-exponential spectral profile, we then employ the generalized Wiener-Khintchine theorem for nonstationary light to derive the two-time mutual coherence function that describes the space-time coherence of the ensuing beams. The isodiffracting nature of the laser resonator modes permits all (paraxial-domain) calculations at any propagation distance to be performed analytically. Significant spatiotemporal coupling is revealed in subcycle, single-cycle, and few-cycle domains, where the partial spatial coherence also leads to reduced temporal coherence even though full spectral coherence is assumed.

  15. Volitional Control of Neuromagnetic Coherence

    Directory of Open Access Journals (Sweden)

    Matthew D Sacchet

    2012-12-01

    Full Text Available Coherence of neural activity between circumscribed brain regions has been implicated as an indicator of intracerebral communication in various cognitive processes. While neural activity can be volitionally controlled with neurofeedback, the volitional control of coherence has not yet been explored. Learned volitional control of coherence could elucidate mechanisms of associations between cortical areas and its cognitive correlates and may have clinical implications. Neural coherence may also provide a signal for brain-computer interfaces (BCI. In the present study we used the Weighted Overlapping Segment Averaging (WOSA method to assess coherence between bilateral magnetoencephalograph (MEG sensors during voluntary digit movement as a basis for BCI control. Participants controlled an onscreen cursor, with a success rate of 124 of 180 (68.9%, sign-test p < 0.001 and 84 out of 100 (84%, sign-test p < 0.001. The present findings suggest that neural coherence may be volitionally controlled and may have specific behavioral correlates.

  16. Coherent quantum logic

    International Nuclear Information System (INIS)

    Finkelstein, D.

    1987-01-01

    The von Neumann quantum logic lacks two basic symmetries of classical logic, that between sets and classes, and that between lower and higher order predicates. Similarly, the structural parallel between the set algebra and linear algebra of Grassmann and Peano was left incomplete by them in two respects. In this work a linear algebra is constructed that completes this correspondence and is interpreted as a new quantum logic that restores these invariances, and as a quantum set theory. It applies to experiments with coherent quantum phase relations between the quantum and the apparatus. The quantum set theory is applied to model a Lorentz-invariant quantum time-space complex

  17. Hadron coherent production

    International Nuclear Information System (INIS)

    Dremin, I.M.

    1981-01-01

    The process of the coherent production of hadrons analogous to Cherenkov radiation of photons is considered. Its appearence and qualitative treatment are possible now because it is known from experiment that the real part of the πp (and pp) forward elastic scattering amplitude is positive at high energies. The threshold behaviour of the process as well as very typical angular and psub(T)-distributions where psub(t)-transverse momentum corresponding to the ring structure of the target diagram at rather large angles and to high-psub(T) jet production are emphasized [ru

  18. Optical coherence refractometry.

    Science.gov (United States)

    Tomlins, Peter H; Woolliams, Peter; Hart, Christian; Beaumont, Andrew; Tedaldi, Matthew

    2008-10-01

    We introduce a novel approach to refractometry using a low coherence interferometer at multiple angles of incidence. We show that for plane parallel samples it is possible to measure their phase refractive index rather than the group index that is usually measured by interferometric methods. This is a significant development because it enables bulk refractive index measurement of scattering and soft samples, not relying on surface measurements that can be prone to error. Our technique is also noncontact and compatible with in situ refractive index measurements. Here, we demonstrate this new technique on a pure silica test piece and a highly scattering resin slab, comparing the results with standard critical angle refractometry.

  19. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  20. Experimental demonstration of an OFDM based visible light communication system using inter-block precoding and superimposed pilots

    Science.gov (United States)

    Zhang, Junwei; Hong, Xuezhi; Liu, Jie; Guo, Changjian

    2018-04-01

    In this work, we investigate and experimentally demonstrate an orthogonal frequency division multiplexing (OFDM) based high speed wavelength-division multiplexed (WDM) visible light communication (VLC) system using an inter-block data precoding and superimposed pilots (DP-SP) based channel estimation (CE) scheme. The residual signal-to-pilot interference (SPI) can be eliminated by using inter-block data precoding, resulting in a significant improvement in estimated accuracy and the overall system performance compared with uncoded SP based CE scheme. We also study the power allocation/overhead problem of the training for DP-SP, uncoded SP and conventional preamble based CE schemes, from which we obtain the optimum signal-to-pilot power ratio (SPR)/overhead percentage for all above cases. Intra-symbol frequency-domain averaging (ISFA) is also adopted to further enhance the accuracy of CE. By using the DP-SP based CE scheme, aggregate data rates of 1.87-Gbit/s and 1.57-Gbit/s are experimentally demonstrated over 0.8-m and 2-m indoor free space transmission, respectively, using a commercially available red, green and blue (RGB) light emitting diode (LED) with WDM. Experimental results show that the DP-SP based CE scheme is comparable to the conventional preamble based CE scheme in term of received Q factor and data rate while entailing a much smaller overhead-size.

  1. Renovascular hypertension in spontaneous hypertensive rats: an experimental model of renal artery stenosis superimposed on essential hypertension.

    Science.gov (United States)

    Rosenthal, T; Bass, A; Grossman, E; Shani, M; Griffel, B; Adar, R

    1987-09-01

    Renovascular hypertension superimposed on essential hypertension, a condition encountered in the elderly, was studied. An experimental animal model consisting of a two-kidney one-clip Goldblatt preparation in the spontaneous hypertensive (SHR) rat, that would simulate this condition, was designed. A 0.25 mm silver clip was placed on the left renal artery of SHR male rats. The same procedure performed on WKY rats served as control. All experiments were performed on low, normal, and rich sodium diet. Systolic blood pressure (BP) was measured by tail-cuff method. Plasma renin concentration (PRC) was determined before and after clipping of the renal artery. Results were as follows: Mean systolic BP increased significantly in clipped rats fed with normal and rich sodium diets. SHR showed an increase from 144 +/- 3 (mean + s.e.m.) to 168 +/- 3 mmHg, and WKY rats showed an increase from 120 +/- 2 to 139 +/- 5 mmHg. There was a two- to threefold rise in PRC. A low-salt diet given prior to clipping prevented the appearance of renovascular hypertension despite a significant rise in PRC. We concluded that renal artery narrowing plays a significant role in the rise of BP in the basically essential type of hypertension.

  2. Persistent 1.5s oscillations superimposed to a solar burst observed at two mm-wavelengths

    International Nuclear Information System (INIS)

    Zodi, A.M.; Kaufmann, P.; Zirin, H.

    1983-05-01

    Long-enduring quasi-periodic oscillations (1.5s) superimposed to a solar burst were by the first time observed simultaneously at two different mm-wayelengths (22 GHz and 44 GHz). The oscillations were present throughout the burst duration (about 10 min), and were delayed at 44 GHz with respect to 22 GHz by 0.3s. The relative amplitude of the oscillation was of about 20 percent at 44 GHz and of about 5 percent at 22 GHz. Interferometer measurements at 10.6 GHz indicated the burst source stable within 1 arcsec. HeD3 line flare indicated two persistent small spots separated by about 10 arcsec. The 22/44 GHz burst position has good correspondence with the HeD3 spots' location. The oscillations display features which appear to distinguish them from ultrafast time structures found in other bursts. One possible interpretation was suggested by assuming a modulation of the gyrosynchrotron emission of trapped electrons by a variable magnetic field on a double burst source, optically thin at 44 GHz and with optical thickness > or equivalent 0.3 at 22 GHz. (Author) [pt

  3. Performance of engine-driven rotary endodontic instruments with a superimposed bending deflection: V. Gates Glidden and Peeso drills.

    Science.gov (United States)

    Brantley, W A; Luebke, N H; Luebke, F L; Mitchell, J C

    1994-05-01

    A laboratory study was performed on Gates Glidden and Peeso drills to determine the incidence of shaft fracture when a bending deflection was superimposed on the rotating drills. Samples of sizes #1 to #6 stainless steel Gates Glidden drills, sizes #1 to #6 stainless steel and carbon steel-type P Peeso drills, and sizes #009 to #023 carbon steel-type B-1 Peeso drills from each of two manufacturers were evaluated with a unique apparatus that applied a 2-mm bending deflection while rotating the instruments. The apparatus did not restrict movement of the bur head during rotation. The test drills were rotated at 2500, 4000, and 7000 revolutions per minute, and the number of revolutions at failure was recorded. Scanning electron microscopic observations established that the stainless steel Gates Glidden and Peeso drills failed by ductile fracture, whereas the carbon steel Peeso drills failed by brittle fracture. Instrument fracture was always near the handpiece shank with this test, and the length of the fractured drills was measured from the working tip. It is recommended that this additional test be adopted to determine fatigue properties of engine-driven rotary endodontic instruments in establishing international performance standards.

  4. Development of a prototype apparatus visualizing on a screen the gamma sources superimposed on the image of the vision field

    Energy Technology Data Exchange (ETDEWEB)

    Imbard, G.; Lemaire, J.E. [CEA Centre d`Etudes de la Vallee du Rhone, 30 - Marcoule (France). Dept. d`Exploitation du Retraitement et de Demantelement; Carcreff, H.; Marchand, L.; Thellier, G. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Reacteurs Experimentaux

    1994-12-31

    Mapping the gamma activity of irradiating zones is often an important prerequisite in dismantling nuclear facilities. The operation is necessary to define a suitable decommissioning strategy before any work begins; it is also required during the procedure to measure the residual activity wherever dose rates are too high to allow human intervention. This report summarizes the work carried out under CEC contract FIED-0055, covering a prototype imaging system designed to display radioactive sources superimposed in real time over a visible light image on a video monitor. This project was developed from an earlier off-line system. The gamma photons are collimated by a double cone system. The imaging system comprises a transparent scintillator bonded to the fiber-optic window of an ultrasensitive camera. The camera was miniaturized to meet specification requirements: with its radiological shielding, the gamma camera weighs 40 kg and is 120 mm in diameter. The processing system is compatible with a realtime camera, and small enough for use at any nuclear. The point-source angular resolution is 1.4 deg. for {sup 60} Co and 0.8 deg. for {sup 137} Cs. The dose rate sensitivity limit is approximately 0.01 mGy.h{sup -1}. Process reliability was confirmed by tests in a high-level radio-metallurgy cell at actual decommissioning site. (authors). 7 figs.

  5. Superimpose methods for uncooled infrared camera applied to the micro-scale thermal characterization of composite materials

    Science.gov (United States)

    Morikawa, Junko

    2015-05-01

    The mobile type apparatus for a quantitative micro-scale thermography using a micro-bolometer was developed based on our original techniques such as an achromatic lens design to capture a micro-scale image in long-wave infrared, a video signal superimposing for the real time emissivity correction, and a pseudo acceleration of a timeframe. The total size of the instrument was designed as it was put in the 17 cm x 28 cm x 26 cm size carrying box. The video signal synthesizer enabled to record a direct digital signal of monitoring temperature or positioning data. The encoded digital signal data embedded in each image was decoded to read out. The protocol to encode/decode the measured data was originally defined. The mixed signals of IR camera and the imposed data were applied to the pixel by pixel emissivity corrections and the pseudo-acceleration of the periodical thermal phenomena. Because the emissivity of industrial materials and biological tissues were usually inhomogeneous, it has the different temperature dependence on each pixel. The time-scale resolution for the periodic thermal event was improved with the algorithm for "pseudoacceleration". It contributes to reduce the noise by integrating the multiple image data, keeping a time resolution. The anisotropic thermal properties of some composite materials such as thermal insulating materials of cellular plastics and the biometric composite materials were analyzed using these techniques.

  6. High-quality and small-capacity e-learning video featuring lecturer-superimposing PC screen images

    Science.gov (United States)

    Nomura, Yoshihiko; Murakami, Michinobu; Sakamoto, Ryota; Sugiura, Tokuhiro; Matsui, Hirokazu; Kato, Norihiko

    2006-10-01

    Information processing and communication technology are progressing quickly, and are prevailing throughout various technological fields. Therefore, the development of such technology should respond to the needs for improvement of quality in the e-learning education system. The authors propose a new video-image compression processing system that ingeniously employs the features of the lecturing scene. While dynamic lecturing scene is shot by a digital video camera, screen images are electronically stored by a PC screen image capturing software in relatively long period at a practical class. Then, a lecturer and a lecture stick are extracted from the digital video images by pattern recognition techniques, and the extracted images are superimposed on the appropriate PC screen images by off-line processing. Thus, we have succeeded to create a high-quality and small-capacity (HQ/SC) video-on-demand educational content featuring the advantages: the high quality of image sharpness, the small electronic file capacity, and the realistic lecturer motion.

  7. Management of pregnancy in pancreas alone transplant recipient complicated with stage-4 chronic renal insufficiency and superimposed pre-eclampsia: Case report and literature review

    Directory of Open Access Journals (Sweden)

    Yung-Shih Lee

    2017-10-01

    Conclusion: Child-bearing in solid organ transplantation recipients has become more promising nowadays, even for a difficult case of pancreas-alone transplant recipient complicated with chronic renal insufficiency and superimposed pre-eclampsia. Thorough antepartum counseling and cautious monitoring of maternal, fetal and graft conditions by multidisciplinary specialties are key to favorable pregnancy outcomes.

  8. Coherent states and rational surfaces

    International Nuclear Information System (INIS)

    Brody, Dorje C; Graefe, Eva-Maria

    2010-01-01

    The state spaces of generalized coherent states associated with special unitary groups are shown to form rational curves and surfaces in the space of pure states. These curves and surfaces are generated by the various Veronese embeddings of the underlying state space into higher dimensional state spaces. This construction is applied to the parameterization of generalized coherent states, which is useful for practical calculations, and provides an elementary combinatorial approach to the geometry of the coherent state space. The results are extended to Hilbert spaces with indefinite inner products, leading to the introduction of a new kind of generalized coherent states.

  9. Regulatory risk coherence

    International Nuclear Information System (INIS)

    Remick, F.J.

    1992-01-01

    As one of the most progressive users of risk assessment in decision making, the US Nuclear Regulatory Commission (NRC) is in a position to play an important role in influencing the development of standard government wide policies for the application of risk assessment in decision making. The NRC, with the support of the nuclear industry, should use the opportunity provided by its experience with risk assessment to actively encourage the adoption of standard national and international health-based safety goals and at the same time accelerate its own efforts to implement the safety goals it has already developed for itself. There are signs of increased recognition of the need for consistency and coherence in the application of risk assessment in government decision making. The NRC and the nuclear industry have recently taken a great step toward establishing a consistant and coherent risk assessment-based culture in the US nuclear industry. As a result of Generic Letter 88-20, which asks each commercial nuclear power plant licensee to perform an individual plant examination by September 1992, for the first time a risk assessment characterizing initiating events in each plant will exist

  10. Ordering states with various coherence measures

    Science.gov (United States)

    Yang, Long-Mei; Chen, Bin; Fei, Shao-Ming; Wang, Zhi-Xi

    2018-04-01

    Quantum coherence is one of the most significant theories in quantum physics. Ordering states with various coherence measures is an intriguing task in quantification theory of coherence. In this paper, we study this problem by use of four important coherence measures—the l_1 norm of coherence, the relative entropy of coherence, the geometric measure of coherence and the modified trace distance measure of coherence. We show that each pair of these measures give a different ordering of qudit states when d≥3. However, for single-qubit states, the l_1 norm of coherence and the geometric coherence provide the same ordering. We also show that the relative entropy of coherence and the geometric coherence give a different ordering for single-qubit states. Then we partially answer the open question proposed in Liu et al. (Quantum Inf Process 15:4189, 2016) whether all the coherence measures give a different ordering of states.

  11. Coherent nonlinear quantum model for composite fermions

    Energy Technology Data Exchange (ETDEWEB)

    Reinisch, Gilbert [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Gudmundsson, Vidar, E-mail: vidar@hi.is [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Manolescu, Andrei [School of Science and Engineering, Reykjavik University, Menntavegur 1, IS-101 Reykjavik (Iceland)

    2014-04-01

    Originally proposed by Read [1] and Jain [2], the so-called “composite-fermion” is a phenomenological quasi-particle resulting from the attachment of two local flux quanta, seen as nonlocal vortices, to electrons situated on a two-dimensional (2D) surface embedded in a strong orthogonal magnetic field. In this Letter this phenomenon is described as a highly-nonlinear and coherent mean-field quantum process of the soliton type by use of a 2D stationary Schrödinger–Poisson differential model with only two Coulomb-interacting electrons. At filling factor ν=1/3 of the lowest Landau level the solution agrees with both the exact two-electron antisymmetric Schrödinger wavefunction and with Laughlin's Jastrow-type guess for the fractional quantum Hall effect, hence providing this latter with a tentative physical justification deduced from the experimental results and based on first principles.

  12. Geometry of spin coherent states

    Science.gov (United States)

    Chryssomalakos, C.; Guzmán-González, E.; Serrano-Ensástiga, E.

    2018-04-01

    Spin states of maximal projection along some direction in space are called (spin) coherent, and are, in many respects, the ‘most classical’ available. For any spin s, the spin coherent states form a 2-sphere in the projective Hilbert space \

  13. Damping of Coherent oscillations

    CERN Document Server

    Vos, L

    1996-01-01

    Damping of coherent oscillations by feedback is straightforward in principle. It has been a vital ingredient for the safe operation of accelerators since a long time. The increasing dimensions and beam intensities of the new generation of hadron colliders impose unprecedented demands on the performance of future systems. The arguments leading to the specification of a transverse feedback system for the CERN SPS in its role as LHC injector and the LHC collider itself are developped to illustrate this. The preservation of the transverse emittance is the guiding principle during this exercise keeping in mind the hostile environment which comprises: transverse impedance bent on developping coupled bunch instabilities, injection errors, unwanted transverse excitation, unavoidable tune spreads and noise in the damping loop.

  14. Quantum information and coherence

    CERN Document Server

    Öhberg, Patrik

    2014-01-01

    This book offers an introduction to ten key topics in quantum information science and quantum coherent phenomena, aimed at graduate-student level. The chapters cover some of the most recent developments in this dynamic research field where theoretical and experimental physics, combined with computer science, provide a fascinating arena for groundbreaking new concepts in information processing. The book addresses both the theoretical and experimental aspects of the subject, and clearly demonstrates how progress in experimental techniques has stimulated a great deal of theoretical effort and vice versa. Experiments are shifting from simply preparing and measuring quantum states to controlling and manipulating them, and the book outlines how the first real applications, notably quantum key distribution for secure communication, are starting to emerge. The chapters cover quantum retrodiction, ultracold quantum gases in optical lattices, optomechanics, quantum algorithms, quantum key distribution, quantum cont...

  15. Integrated coherent matter wave circuits

    International Nuclear Information System (INIS)

    Ryu, C.; Boshier, M. G.

    2015-01-01

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through their electric polarizability. Moreover, the source of coherent matter waves is a Bose-Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry

  16. Reduction of parasitic interferences in digital holographic microscopy by numerically decreased coherence length

    Science.gov (United States)

    Kosmeier, S.; Langehanenberg, P.; von Bally, G.; Kemper, B.

    2012-01-01

    Due to the large coherence length of laser light, optical path length (OPL) resolution in laser based digital holographic microscopy suffers from parasitic interferences caused by multiple reflections within the experimental setup. Use of partially coherent light reduces this drawback but requires precise and stable matching of object and reference arm's OPLs and limits the spatial frequency of the interference pattern in off-axis holography. Here, we investigate if the noise properties of spectrally broadened light sources can be generated numerically. Therefore, holograms are coherently captured at different laser wavelengths and the corresponding reconstructed wave fields are numerically superimposed utilizing variable weightings. Gaussian and rectangular spectral shapes of the so synthesized field are analyzed with respect to the resulting noise level, which is quantified in OPL distributions of a reflective test target. Utilizing a Gaussian weighting, the noise level is found to be similar to the one obtained with the partially coherent light of a superluminescent diode. With a rectangular shaped synthesized spectrum, noise is reduced more efficient than with a Gaussian one. The applicability of the method in label-free cell analysis is demonstrated by quantitative phase contrast images obtained from living cancer cells.

  17. A finite element calculation of flux pumping

    Science.gov (United States)

    Campbell, A. M.

    2017-12-01

    A flux pump is not only a fascinating example of the power of Faraday’s concept of flux lines, but also an attractive way of powering superconducting magnets without large electronic power supplies. However it is not possible to do this in HTS by driving a part of the superconductor normal, it must be done by exceeding the local critical density. The picture of a magnet pulling flux lines through the material is attractive, but as there is no direct contact between flux lines in the magnet and vortices, unless the gap between them is comparable to the coherence length, the process must be explicable in terms of classical electromagnetism and a nonlinear V-I characteristic. In this paper a simple 2D model of a flux pump is used to determine the pumping behaviour from first principles and the geometry. It is analysed with finite element software using the A formulation and FlexPDE. A thin magnet is passed across one or more superconductors connected to a load, which is a large rectangular loop. This means that the self and mutual inductances can be calculated explicitly. A wide strip, a narrow strip and two conductors are considered. Also an analytic circuit model is analysed. In all cases the critical state model is used, so the flux flow resistivity and dynamic resistivity are not directly involved, although an effective resistivity appears when J c is exceeded. In most of the cases considered here is a large gap between the theory and the experiments. In particular the maximum flux transferred to the load area is always less than the flux of the magnet. Also once the threshold needed for pumping is exceeded the flux in the load saturates within a few cycles. However the analytic circuit model allows a simple modification to allow for the large reduction in I c when the magnet is over a conductor. This not only changes the direction of the pumped flux but leads to much more effective pumping.

  18. Compact neutron flux monitor

    International Nuclear Information System (INIS)

    Madhavi, V.; Phatak, P.R.; Bahadur, C.; Bayala, A.K.; Jakati, R.K.; Sathian, V.

    2003-01-01

    Full text: A compact size neutron flux monitor has been developed incorporating standard boards developed for smart radiation monitors. The sensitivity of the monitors is 0.4cps/nV. It has been tested up to 2075 nV flux with standard neutron sources. It shows convincing results even in high flux areas like 6m away from the accelerator in RMC (Parel) for 106/107 nV. These monitors have a focal and remote display, alarm function with potential free contacts for centralized control and additional provision of connectivity via RS485/Ethernet. This paper describes the construction, working and results of the above flux monitor

  19. Flux-induced Nernst effect in low-dimensional superconductors

    International Nuclear Information System (INIS)

    Berger, Jorge

    2017-01-01

    Highlights: • The Nernst effect tells us that the presence of a magnetic field and a temperature gradient in a conductor yields a transverse voltage. • The Nernst effect in superconductors, especially above their critical temperature, has been a hot topic of research during the last decades. • I predict a new effect in which a transverse voltage arises, not because of the magnetic field, but rather because of the magnetic flux enclosed by a loop with non-uniform temperature. - Abstract: A method is available that enables consistent study of the stochastic behavior of a system that obeys purely diffusive evolution equations. This method has been applied to a superconducting loop with nonuniform temperature, with average temperature close to T_c. It is found that a flux-dependent average potential difference arises along the loop, proportional to the temperature gradient and most pronounced in the direction perpendicular to this gradient. The largest voltages were obtained for fluxes close to 0.3Φ_0, average temperatures slightly below the critical temperature, thermal coherence length of the order of the perimeter of the ring, BCS coherence length that is not negligible in comparison to the thermal coherence length, and short inelastic scattering time. This effect is entirely due to thermal fluctuations. It differs essentially from the usual Nernst effect in bulk superconductors, that is induced by magnetic field rather than by magnetic flux. We also study the effect of confinement in a 2D mesoscopic film.

  20. 2-Iminobiotin Superimposed on Hypothermia Protects Human Neuronal Cells from Hypoxia-Induced Cell Damage: An in Vitro Study

    Directory of Open Access Journals (Sweden)

    Karina Zitta

    2018-01-01

    Full Text Available Perinatal asphyxia represents one of the major causes of neonatal morbidity and mortality. Hypothermia is currently the only established treatment for hypoxic-ischemic encephalopathy (HIE, but additional pharmacological strategies are being explored to further reduce the damage after perinatal asphyxia. The aim of this study was to evaluate whether 2-iminobiotin (2-IB superimposed on hypothermia has the potential to attenuate hypoxia-induced injury of neuronal cells. In vitro hypoxia was induced for 7 h in neuronal IMR-32 cell cultures. Afterwards, all cultures were subjected to 25 h of hypothermia (33.5°C, and incubated with vehicle or 2-IB (10, 30, 50, 100, and 300 ng/ml. Cell morphology was evaluated by brightfield microscopy. Cell damage was analyzed by LDH assays. Production of reactive oxygen species (ROS was measured using fluorometric assays. Western blotting for PARP, Caspase-3, and the phosphorylated forms of akt and erk1/2 was conducted. To evaluate early apoptotic events and signaling, cell protein was isolated 4 h post-hypoxia and human apoptosis proteome profiler arrays were performed. Twenty-five hour after the hypoxic insult, clear morphological signs of cell damage were visible and significant LDH release as well as ROS production were observed even under hypothermic conditions. Post-hypoxic application of 2-IB (10 and 30 ng/ml reduced the hypoxia-induced LDH release but not ROS production. Phosphorylation of erk1/2 was significantly increased after hypoxia, while phosphorylation of akt, protein expression of Caspase-3 and cleavage of PARP were only slightly increased. Addition of 2-IB did not affect any of the investigated proteins. Apoptosis proteome profiler arrays performed with cellular protein obtained 4 h after hypoxia revealed that post-hypoxic application of 2-IB resulted in a ≥ 25% down regulation of 10/35 apoptosis-related proteins: Bad, Bax, Bcl-2, cleaved Caspase-3, TRAILR1, TRAILR2, PON2, p21, p27, and phospho

  1. Dependence of the frequency spectrum of small amplitude vibrations superimposed on finite deformations of a nonlinear, cylindrical elastic body on residual stress

    KAUST Repository

    Gorb, Yuliya

    2010-11-01

    We model and analyze the response of nonlinear, residually stressed elastic bodies subjected to small amplitude vibrations superimposed upon large deformations. The problem derives from modeling the use of intravascular ultrasound (IVUS) imaging to interrogate atherosclerotic plaques in vivo in large arteries. The goal of this investigation is twofold: (i) introduce a modeling framework for residual stress that unlike traditional Fung type classical opening angle models may be used for a diseased artery, and (ii) investigate the sensitivity of the spectra of small amplitude high frequency time harmonic vibrations superimposed on a large deformation to the details of the residual stress stored in arteries through a numerical simulation using physiologic parameter values under both low and high blood pressure loadings. The modeling framework also points the way towards an inverse problem using IVUS techniques to estimate residual stress in healthy and diseased arteries. © 2010 Elsevier Ltd. All rights reserved.

  2. International workshop on phase retrieval and coherent scattering. Coherence 2005

    International Nuclear Information System (INIS)

    Nugent, K.A.; Fienup, J.R.; Van Dyck, D.; Van Aert, S.; Weitkamp, T.; Diaz, A.; Pfeiffer, F.; Cloetens, P.; Stampanoni, M.; Bunk, O.; David, C.; Bronnikov, A.V.; Shen, Q.; Xiao, X.; Gureyev, T.E.; Nesterets, Ya.I.; Paganin, D.M.; Wilkins, S.W.; Mokso, R.; Cloetens, P.; Ludwig, W.; Hignette, O.; Maire, E.; Faulkner, H.M.L.; Rodenburg, J.M.; Wu, X.; Liu, H.; Grubel, G.; Ludwig, K.F.; Livet, F.; Bley, F.; Simon, J.P.; Caudron, R.; Le Bolloc'h, D.; Moussaid, A.; Gutt, C.; Sprung, M.; Madsen, A.; Tolan, M.; Sinha, S.K.; Scheffold, F.; Schurtenberger, P.; Robert, A.; Madsen, A.; Falus, P.; Borthwick, M.A.; Mochrie, S.G.J.; Livet, F.; Sutton, M.D.; Ehrburger-Dolle, F.; Bley, F.; Geissler, E.; Sikharulidze, I.; Jeu, W.H. de; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Naryanan, S.; Sinha, S.K.; Lal, J.; Naryanan, S.; Sinha, S.K.; Lal, J.; Robinson, I.K.; Chapman, H.N.; Barty, A.; Beetz, T.; Cui, C.; Hajdu, J.; Hau-Riege, S.P.; He, H.; Stadler, L.M.; Sepiol, B.; Harder, R.; Robinson, I.K.; Zontone, F.; Vogl, G.; Howells, M.; London, R.; Marchesini, S.; Shapiro, D.; Spence, J.C.H.; Weierstall, U.; Eisebitt, S.; Shapiro, D.; Lima, E.; Elser, V.; Howells, M.R.; Huang, X.; Jacobsen, C.; Kirz, J.; Miao, H.; Neiman, A.; Sayre, D.; Thibault, P.; Vartanyants, I.A.; Robinson, I.K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J.; Pfeiffer, F.; Metzger, H.; Zhong, Z.; Bauer, G.; Nishino, Y.; Miao, J.; Kohmura, Y.; Yamamoto, M.; Takahashi, Y.; Koike, K.; Ebisuzaki, T.; Ishikawa, T.; Spence, J.C.H.; Doak, B.

    2005-01-01

    The contributions of the participants have been organized into 3 topics: 1) phase retrieval methods, 2) X-ray photon correlation spectroscopy, and 3) coherent diffraction imaging. This document gathers the abstracts of the presentations and of the posters

  3. International workshop on phase retrieval and coherent scattering. Coherence 2005

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, K.A.; Fienup, J.R.; Van Dyck, D.; Van Aert, S.; Weitkamp, T.; Diaz, A.; Pfeiffer, F.; Cloetens, P.; Stampanoni, M.; Bunk, O.; David, C.; Bronnikov, A.V.; Shen, Q.; Xiao, X.; Gureyev, T.E.; Nesterets, Ya.I.; Paganin, D.M.; Wilkins, S.W.; Mokso, R.; Cloetens, P.; Ludwig, W.; Hignette, O.; Maire, E.; Faulkner, H.M.L.; Rodenburg, J.M.; Wu, X.; Liu, H.; Grubel, G.; Ludwig, K.F.; Livet, F.; Bley, F.; Simon, J.P.; Caudron, R.; Le Bolloc' h, D.; Moussaid, A.; Gutt, C.; Sprung, M.; Madsen, A.; Tolan, M.; Sinha, S.K.; Scheffold, F.; Schurtenberger, P.; Robert, A.; Madsen, A.; Falus, P.; Borthwick, M.A.; Mochrie, S.G.J.; Livet, F.; Sutton, M.D.; Ehrburger-Dolle, F.; Bley, F.; Geissler, E.; Sikharulidze, I.; Jeu, W.H. de; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Naryanan, S.; Sinha, S.K.; Lal, J.; Naryanan, S.; Sinha, S.K.; Lal, J.; Robinson, I.K.; Chapman, H.N.; Barty, A.; Beetz, T.; Cui, C.; Hajdu, J.; Hau-Riege, S.P.; He, H.; Stadler, L.M.; Sepiol, B.; Harder, R.; Robinson, I.K.; Zontone, F.; Vogl, G.; Howells, M.; London, R.; Marchesini, S.; Shapiro, D.; Spence, J.C.H.; Weierstall, U.; Eisebitt, S.; Shapiro, D.; Lima, E.; Elser, V.; Howells, M.R.; Huang, X.; Jacobsen, C.; Kirz, J.; Miao, H.; Neiman, A.; Sayre, D.; Thibault, P.; Vartanyants, I.A.; Robinson, I.K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J.; Pfeiffer, F.; Metzger, H.; Zhong, Z.; Bauer, G.; Nishino, Y.; Miao, J.; Kohmura, Y.; Yamamoto, M.; Takahashi, Y.; Koike, K.; Ebisuzaki, T.; Ishikawa, T.; Spence, J.C.H.; Doak, B

    2005-07-01

    The contributions of the participants have been organized into 3 topics: 1) phase retrieval methods, 2) X-ray photon correlation spectroscopy, and 3) coherent diffraction imaging. This document gathers the abstracts of the presentations and of the posters.

  4. Perturbative coherence in field theory

    International Nuclear Information System (INIS)

    Aldrovandi, R.; Kraenkel, R.A.

    1987-01-01

    A general condition for coherent quantization by perturbative methods is given, because the basic field equations of a fild theory are not always derivable from a Lagrangian. It's seen that non-lagrangian models way have well defined vertices, provided they satisfy what they call the 'coherence condition', which is less stringent than the condition for the existence of a Lagrangian. They note that Lagrangian theories are perturbatively coherent, in the sense that they have well defined vertices, and that they satisfy automatically that condition. (G.D.F.) [pt

  5. Models of coherent exciton condensation

    International Nuclear Information System (INIS)

    Littlewood, P B; Eastham, P R; Keeling, J M J; Marchetti, F M; Simons, B D; Szymanska, M H

    2004-01-01

    That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers

  6. Models of coherent exciton condensation

    Energy Technology Data Exchange (ETDEWEB)

    Littlewood, P B [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Eastham, P R [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Keeling, J M J [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Marchetti, F M [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Simons, B D [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Szymanska, M H [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom)

    2004-09-08

    That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers.

  7. Optimally cloned binary coherent states

    Science.gov (United States)

    Müller, C. R.; Leuchs, G.; Marquardt, Ch.; Andersen, U. L.

    2017-10-01

    Binary coherent state alphabets can be represented in a two-dimensional Hilbert space. We capitalize this formal connection between the otherwise distinct domains of qubits and continuous variable states to map binary phase-shift keyed coherent states onto the Bloch sphere and to derive their quantum-optimal clones. We analyze the Wigner function and the cumulants of the clones, and we conclude that optimal cloning of binary coherent states requires a nonlinearity above second order. We propose several practical and near-optimal cloning schemes and compare their cloning fidelity to the optimal cloner.

  8. How a 10-day heatwave impacts barley grain yield when superimposed onto future levels of temperature and CO2 as single and combined factors

    DEFF Research Database (Denmark)

    Heinz Ingvordsen, Cathrine; Lyngkjær, Michael F.; Peltonen-Sainio, Pirjo

    2018-01-01

    Heatwaves pose a threat to crop production and are predicted to increase in frequency, length and intensity as a consequence of global warming. Future heatwaves will occur in addition to the ongoing increase of mean temperature and CO2. To test effects of heatwaves superimposed to future climate ...... exposure, leading to a strong decline in the harvest index. Our results strongly emphasize the need to produce heatwave resilient cultivars....

  9. Superimposed dual-isotope SPECT using 99mTc-hydroxymethylene diphosphonate and 201Tl-chloride to assess cartilage invasion in laryngohypopharyngeal cancer

    International Nuclear Information System (INIS)

    Nishiyama, Yoshihiro; Yamamoto, Yuka; Yokoe, Koiku; Miyabe, Kazunori; Iwasaki, Takanobu; Toyama, Yoshihiro; Satoh, Katashi; Ohkawa, Motoomi

    2004-01-01

    Cartilage invasion in laryngohypopharyngeal cancer has a significant impact on the choice of treatment modality and outcome of the disease. We examined invasion of cartilage in laryngohypopharyngeal cancer by simultaneous bone and tumor dual-isotope SPECT using 99m Tc-hydroxymethylene diphosphonate and 201 Tl-chloride. Early and delayed simultaneous bone and tumor dual-isotope SPECT were performed on 19 patients with laryngohypopharyngeal cancer. Dual-isotope SPECT images were superimposed to project tumor location from tumor SPECT onto the osseous structures shown by bone SPECT. The presence or absence of cartilage invasion was evaluated histopathologically or by radiological studies such as CT and/or MRI. Histopathological or radiological examination of the cartilage revealed invasion in 5 patients and no invasion in 14 patients. The results of both early and delayed dual-isotope SPECT were exactly the same. Using dual-isotope SPECT, the sensitivity, specificity, and accuracy in detecting cartilage invasion by laryngohypopharyngeal cancer were: 80% (4/5), 92.9% (13/14), and 89.5% (17/19), respectively. Results of the present study suggest that superimposed early bone and tumor dual-isotope SPECT images may be sufficient for the diagnostic evaluation of cartilage invasion by laryngohypopharyngeal cancer. Superimposed dual-isotope SPECT imaging is a useful technique in the evaluation of cartilage invasion in laryngohypopharyngeal cancer. (author)

  10. Pre-eruptive Magnetic Reconnection within a Multi-flux-rope System in the Solar Corona

    Science.gov (United States)

    Awasthi, Arun Kumar; Liu, Rui; Wang, Haimin; Wang, Yuming; Shen, Chenglong

    2018-04-01

    The solar corona is frequently disrupted by coronal mass ejections (CMEs), whose core structure is believed to be a flux rope made of helical magnetic field. This has become a “standard” picture; though, it remains elusive how the flux rope forms and evolves toward eruption. While one-third of the ejecta passing through spacecraft demonstrate a flux-rope structure, the rest have complex magnetic fields. Are they originating from a coherent flux rope, too? Here we investigate the source region of a complex ejecta, focusing on a flare precursor with definitive signatures of magnetic reconnection, i.e., nonthermal electrons, flaring plasma, and bidirectional outflowing blobs. Aided by nonlinear force-free field modeling, we conclude that the reconnection occurs within a system of multiple braided flux ropes with different degrees of coherency. The observation signifies the importance of internal structure and dynamics in understanding CMEs and in predicting their impacts on Earth.

  11. Primary cosmic ray flux

    Energy Technology Data Exchange (ETDEWEB)

    Stanev, Todor

    2001-05-01

    We discuss the primary cosmic ray flux from the point of view of particle interactions and production of atmospheric neutrinos. The overall normalization of the cosmic ray flux and its time variations and site dependence are major ingredients of the atmospheric neutrino predictions and the basis for the derivation of the neutrino oscillation parameters.

  12. Flux cutting in superconductors

    International Nuclear Information System (INIS)

    Campbell, A M

    2011-01-01

    This paper describes experiments and theories of flux cutting in superconductors. The use of the flux line picture in free space is discussed. In superconductors cutting can either be by means of flux at an angle to other layers of flux, as in longitudinal current experiments, or due to shearing of the vortex lattice as in grain boundaries in YBCO. Experiments on longitudinal currents can be interpreted in terms of flux rings penetrating axial lines. More physical models of flux cutting are discussed but all predict much larger flux cutting forces than are observed. Also, cutting is occurring at angles between vortices of about one millidegree which is hard to explain. The double critical state model and its developments are discussed in relation to experiments on crossed and rotating fields. A new experiment suggested by Clem gives more direct information. It shows that an elliptical yield surface of the critical state works well, but none of the theoretical proposals for determining the direction of E are universally applicable. It appears that, as soon as any flux flow takes place, cutting also occurs. The conclusion is that new theories are required. (perspective)

  13. FAME, the Flux Analysis and Modeling Environment

    Directory of Open Access Journals (Sweden)

    Boele Joost

    2012-01-01

    Full Text Available Abstract Background The creation and modification of genome-scale metabolic models is a task that requires specialized software tools. While these are available, subsequently running or visualizing a model often relies on disjoint code, which adds additional actions to the analysis routine and, in our experience, renders these applications suboptimal for routine use by (systems biologists. Results The Flux Analysis and Modeling Environment (FAME is the first web-based modeling tool that combines the tasks of creating, editing, running, and analyzing/visualizing stoichiometric models into a single program. Analysis results can be automatically superimposed on familiar KEGG-like maps. FAME is written in PHP and uses the Python-based PySCeS-CBM for its linear solving capabilities. It comes with a comprehensive manual and a quick-start tutorial, and can be accessed online at http://f-a-m-e.org/. Conclusions With FAME, we present the community with an open source, user-friendly, web-based "one stop shop" for stoichiometric modeling. We expect the application will be of substantial use to investigators and educators alike.

  14. Heat flux microsensor measurements

    Science.gov (United States)

    Terrell, J. P.; Hager, J. M.; Onishi, S.; Diller, T. E.

    1992-01-01

    A thin-film heat flux sensor has been fabricated on a stainless steel substrate. The thermocouple elements of the heat flux sensor were nickel and nichrome, and the temperature resistance sensor was platinum. The completed heat flux microsensor was calibrated at the AEDC radiation facility. The gage output was linear with heat flux with no apparent temperature effect on sensitivity. The gage was used for heat flux measurements at the NASA Langley Vitiated Air Test Facility. Vitiated air was expanded to Mach 3.0 and hydrogen fuel was injected. Measurements were made on the wall of a diverging duct downstream of the injector during all stages of the hydrogen combustion tests. Because the wall and the gage were not actively cooled, the wall temperature reached over 1000 C (1900 F) during the most severe test.

  15. Coherence of light. 2. ed.

    International Nuclear Information System (INIS)

    Perina, J.

    1985-01-01

    This book puts the theory of coherence of light on a rigorous mathematical footing. It deals with the classical and quantum theories and with their inter-relationships, including many results from the author's own research. Particular attention is paid to the detection of optical fields, using the correlation functions, photocount statistics and coherent state. Radiometry with light fields of arbitrary states of coherence is discussed and the coherent state methods are demonstrated by photon statistics of radiation in random and nonlinear media, using the Heisenberg-Langevin and Fokker-Planck approaches to the interaction of radiation with matter. Many experimental and theoretical results are compared. A full list of references to theoretical and experimental literature is provided. The book is intended for researchers and postgraduate students in the fields of quantum optics, quantum electronics, statistical optics, nonlinear optics, optical communication and optoelectronics. (Auth.)

  16. Spin Coherence in Semiconductor Nanostructures

    National Research Council Canada - National Science Library

    Flatte, Michael E

    2006-01-01

    ... dots, tuning of spin coherence times for electron spin, tuning of dipolar magnetic fields for nuclear spin, spontaneous spin polarization generation and new designs for spin-based teleportation and spin transistors...

  17. Soft gluon coherence at LEP

    International Nuclear Information System (INIS)

    Gaidot, A.

    1993-01-01

    After a brief overview of the experimental status on colour coherence at LEP we will focus on two recent approaches to the subject: the sub-jet multiplicities and the azimuthal correlations between pair of particles. (author)

  18. Coherence matrix of plasmonic beams

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Lavrinenko, Andrei

    2013-01-01

    We consider monochromatic electromagnetic beams of surface plasmon-polaritons created at interfaces between dielectric media and metals. We theoretically study non-coherent superpositions of elementary surface waves and discuss their spectral degree of polarization, Stokes parameters, and the for...... of the spectral coherence matrix. We compare the polarization properties of the surface plasmonspolaritons as three-dimensional and two-dimensional fields concluding that the latter is superior....

  19. Coherent systems with multistate components

    International Nuclear Information System (INIS)

    Caldarola, L.

    1980-01-01

    The basic rules of the Boolean algebra with restrictions on variables are briefly recalled. This special type of Boolean algebra allows one to handle fault trees of systems made of multistate (two or more than two states) components. Coherent systems are defined in the case of multistate components. This definition is consistent with that originally suggested by Barlow in the case of binary (two states) components. The basic properties of coherence are described and discussed. Coherent Boolean functions are also defined. It is shown that these functions are irredundant, that is they have only one base which is at the same time complete and irredundant. However, irredundant functions are not necessarily coherent. Finally a simplified algorithm for the calculation of the base of a coherent function is described. In the case that the function is not coherent, the algorithm can be used to reduce the size of the normal disjunctive form of the function. This in turn eases the application of the Nelson algorithm to calculate the complete base of the function. The simplified algorithm has been built in the computer program MUSTAFA-1. In a sample case the use of this algorithm caused a reduction of the CPU time by a factor of about 20. (orig.)

  20. Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Pier Alberto Testoni

    2007-01-01

    Full Text Available Optical coherence tomography (OCT is an optical imaging modality that performs high-resolution, cross-sectional, subsurface tomographic imaging of the microstructure of tissues. The physical principle of OCT is similar to that of B-mode ultrasound imaging, except that it uses infrared light waves rather than acoustic waves. The in vivo resolution is 10–25 times better (about 10 µm than with high-frequency ultrasound imaging, but the depth of penetration is limited to 1–3 mm, depending on tissue structure, depth of focus of the probe used, and pressure applied to the tissue surface. In the last decade, OCT technology has evolved from an experimental laboratory tool to a new diagnostic imaging modality with a wide spectrum of clinical applications in medical practice, including the gastrointestinal tract and pancreatico-biliary ductal system. OCT imaging from the gastrointestinal tract can be done in humans by using narrow-diameter, catheter-based probes that can be inserted through the accessory channel of either a conventional front-view endoscope, for investigating the epithelial structure of the gastrointestinal tract, or a side-view endoscope, inside a standard transparent ERCP (endoscopic retrograde cholangiopancreatography catheter, for investigating the pancreatico-biliary ductal system. The esophagus and esophagogastric junction have been the most widely investigated organs so far; more recently, duodenum, colon, and the pancreatico-biliary ductal system have also been extensively investigated. OCT imaging of the gastrointestinal wall structure is characterized by a multiple-layer architecture that permits an accurate evaluation of the mucosa, lamina propria, muscularis mucosae, and part of the submucosa. The technique may therefore be used to identify preneoplastic conditions of the gastrointestinal tract, such as Barrett's epithelium and dysplasia, and evaluate the depth of penetration of early-stage neoplastic lesions. OCT imaging

  1. Coherent transport through interacting quantum dots

    International Nuclear Information System (INIS)

    Hiltscher, Bastian

    2012-01-01

    The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

  2. Coherent transport through interacting quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Hiltscher, Bastian

    2012-10-05

    The present thesis is composed of four different works. All deal with coherent transport through interacting quantum dots, which are tunnel-coupled to external leads. There a two main motivations for the use of quantum dots. First, they are an ideal device to study the influence of strong Coulomb repulsion, and second, their discrete energy levels can easily be tuned by external gate electrodes to create different transport regimes. The expression of coherence includes a very wide range of physical correlations and, therefore, the four works are basically independent of each other. Before motivating and introducing the different works in more detail, we remark that in all works a diagrammatic real-time perturbation theory is used. The fermionic degrees of freedom of the leads are traced out and the elements of the resulting reduced density matrix can be treated explicitly by means of a generalized master equation. How this equation is solved, depends on the details of the problem under consideration. In the first of the four works adiabatic pumping through an Aharonov-Bohm interferometer with a quantum dot embedded in each of the two arms is studied. In adiabatic pumping transport is generated by varying two system parameters periodically in time. We consider the two dot levels to be these two pumping parameters. Since they are located in different arms of the interferometer, pumping is a quantum mechanical effect purely relying on coherent superpositions of the dot states. It is very challenging to identify a quantum pumping mechanism in experiments, because a capacitive coupling of the gate electrodes to the leads may yield an undesired AC bias voltage, which is rectified by a time dependent conductance. Therefore, distinguishing features of these two transport mechanisms are required. We find that the dependence on the magnetic field is the key feature. While the pumped charge is an odd function of the magnetic flux, the rectified current is even, at least in

  3. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-08-01

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  4. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-09-12

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  5. Intense structures of different momentum fluxes in turbulent channels

    Science.gov (United States)

    Osawa, Kosuke; Jiménez, Javier

    2018-04-01

    The effect of different definitions of the momentum flux on the properties of the coherent structures of the logarithmic region of wall-bounded turbulence is investigated by comparing the structures of intense tangential Reynolds stress with those of the alternative flux proposed in [Jimenez (2016) J. Fluid Mech. 809:585]. Despite the fairly different statistical properties of the two flux definitions, it is found that their intense structures show many similarities, such as the dominance of ‘wall-attached’ objects, and geometric self-similarity. However, the new structures are wider, although not taller, than the classical ones, and include both high- and low-momentum regions within the same object. It is concluded that they represent the same phenomenon as the classical group of a sweep, an ejection, and a roller, which should thus be considered as the fundamental coherent structure of the momentum flux. The present results suggest that the properties of these momentum structures are robust with respect to the definition of the fluxes.

  6. Coherent communication with continuous quantum variables

    Science.gov (United States)

    Wilde, Mark M.; Krovi, Hari; Brun, Todd A.

    2007-06-01

    The coherent bit (cobit) channel is a resource intermediate between classical and quantum communication. It produces coherent versions of teleportation and superdense coding. We extend the cobit channel to continuous variables by providing a definition of the coherent nat (conat) channel. We construct several coherent protocols that use both a position-quadrature and a momentum-quadrature conat channel with finite squeezing. Finally, we show that the quality of squeezing diminishes through successive compositions of coherent teleportation and superdense coding.

  7. Experimental generation of optical coherence lattices

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yahong; Cai, Yangjian, E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Ponomarenko, Sergey A., E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [Department of Electrical and Computer Engineering, Dalhousie University, Halifax, Nova Scotia B3J 2X4 (Canada)

    2016-08-08

    We report experimental generation and measurement of recently introduced optical coherence lattices. The presented optical coherence lattice realization technique hinges on a superposition of mutually uncorrelated partially coherent Schell-model beams with tailored coherence properties. We show theoretically that information can be encoded into and, in principle, recovered from the lattice degree of coherence. Our results can find applications to image transmission and optical encryption.

  8. CIRCE, the Coherent Infrared Center at the ALS

    International Nuclear Information System (INIS)

    Byrd, John M.; De Santis, Stefano; Jung, Jin-Young; Li, Derun; Martin, Michael C.; McKinney, W.; Munson, Dawn; Nishimura, Hiroshi; Robin, David S.; Sannibale, Fernando; Schlueter, Ross; Venturini, Marco; Wan, Weishi; Zolotorev, Max

    2004-01-01

    CIRCE (Coherent InfraRed CEnter) is a proposal for a new electron storage ring to be built at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). The ring design is optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. Among others, CIRCE operation includes three interesting CSR modes: ultra stable, femtosecond laser slicing and broadband bursting. CSR allows CIRCE to generate an extremely high flux in the terahertz frequency region. The many orders of magnitude increase in the intensity over that presently achievable by conventional sources, has the potential to enable new science experiments. The characteristics of CIRCE and of the different modes of operation are described in this paper

  9. A fast radiation-to-coherent light converter

    International Nuclear Information System (INIS)

    Wang, C.L.; Flatley, J.E.; Stewart, P.H.

    1988-01-01

    We have developed a radiation-to-coherent light converter (RCLC) with a monolithically integrated semiconductor chip that consists of a chromium-doped GaAs photoconductor detector modulates the laser diode, which has been biased above the lasing threshold, thus converting a radiation pulse to an electric pulse and then to a light pulse. The laser pulse is then transmitted to a fast recorder through a high-bandwidth optical fiber. In the absence of a single-step x-ray pumped laser, our converter appears to be the first integrated device that can efficiently convert x-ray flux into coherent light. This device has been tested successfully with the 50-ps electron beams of a 17-MeV linear accelerator and with 50-ns x-ray pulses from a Z-pinch plasma source. 2 refs., 9 figs

  10. WEB COHERENCE LEARNING

    Directory of Open Access Journals (Sweden)

    Peter Karlsudd

    2008-09-01

    Full Text Available This article describes a learning system constructed to facilitate teaching and learning by creating a functional web-based contact between schools and organisations which in cooperation with the school contribute to pupils’/students’ cognitive development. Examples of such organisations include science centres, museums, art and music workshops and teacher education internships. With the support of the “Web Coherence Learning” IT application (abbreviated in Swedish to Webbhang developed by the University of Kalmar, the aim is to reinforce learning processes in the encounter with organisations outside school. In close cooperation with potential users a system was developed which can be described as consisting of three modules. The first module, “the organisation page” supports the organisation in simply setting up a homepage, where overarching information on organisation operations can be published and where functions like calendar, guestbook, registration and newsletter can be included. In the second module, “the activity page” the activities offered by the organisation are described. Here pictures and information may prepare and inspire pupils/students to their own activities before future visits. The third part, “the participant page” is a communication module linked to the activity page enabling school classes to introduce themselves and their work as well as documenting the work and communicating with the educators responsible for external activities. When the project is finished, the work will be available to further school classes, parents and other interested parties. System development and testing have been performed in a small pilot study where two creativity educators at an art museum have worked together with pupils and teachers from a compulsory school class. The system was used to establish, prior to the visit of the class, a deeper contact and to maintain a more qualitative continuous dialogue during and after

  11. Continuous magnetic flux pump

    Science.gov (United States)

    Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

    1966-01-01

    A method and means for altering the intensity of a magnetic field by transposing flux from one location to the location desired fro the magnetic field are examined. The device described includes a pair of communicating cavities formed in a block of superconducting material, is dimensioned to be insertable into one of the cavities and to substantially fill the cavity. Magnetic flux is first trapped in the cavities by establishing a magnetic field while the superconducting material is above the critical temperature at which it goes superconducting. Thereafter, the temperature of the material is reduced below the critical value, and then the exciting magnetic field may be removed. By varying the ratios of the areas of the two cavities, it is possible to produce a field having much greater flux density in the second, smaller cavity, into which the flux transposed.

  12. Flux in Tallinn

    Index Scriptorium Estoniae

    2004-01-01

    Rahvusvahelise elektroonilise kunsti sümpoosioni ISEA2004 klubiõhtu "Flux in Tallinn" klubis Bon Bon. Eestit esindasid Ropotator, Ars Intel Inc., Urmas Puhkan, Joel Tammik, Taavi Tulev (pseud. Wochtzchee). Klubiõhtu koordinaator Andres Lõo

  13. Flux shunts for undulators

    International Nuclear Information System (INIS)

    Hoyer, E.; Chin, J.; Hassenzahl, W.V.

    1993-05-01

    Undulators for high-performance applications in synchrotron-radiation sources and periodic magnetic structures for free-electron lasers have stringent requirements on the curvature of the electron's average trajectory. Undulators using the permanent magnet hybrid configuration often have fields in their central region that produce a curved trajectory caused by local, ambient magnetic fields such as those of the earth. The 4.6 m long Advanced Light Source (ALS) undulators use flux shunts to reduce this effect. These flux shunts are magnetic linkages of very high permeability material connecting the two steel beams that support the magnetic structures. The shunts reduce the scalar potential difference between the supporting beams and carry substantial flux that would normally appear in the undulator gap. Magnetic design, mechanical configuration of the flux shunts and magnetic measurements of their effect on the ALS undulators are described

  14. Neutron flux monitor

    International Nuclear Information System (INIS)

    Oda, Naotaka.

    1993-01-01

    The device of the present invention greatly saves an analog processing section such as an analog filter and an analog processing circuit. That is, the device of the present invention comprises (1) a neutron flux detection means for detecting neutron fluxed in the reactor, (2) a digital filter means for dividing signals corresponding to the detected neutron fluxes into predetermined frequency band regions, (3) a calculation processing means for applying a calculation processing corresponding to the frequency band regions to the neutron flux detection signals divided by the digital filter means. With such a constitution, since the neutron detection signals are processed by the digital filter means, the accuracy is improved and the change for the property of the filter is facilitated. Further, when a neutron flux level is obtained, a calculation processing corresponding to the frequency band region can be conducted without the analog processing circuit. Accordingly, maintenance and accuracy are improved by greatly decreasing the number of parts. Further, since problems inherent to the analog circuit are solved, neutron fluxes are monitored at high reliability. (I.S.)

  15. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro.

    1995-01-01

    In a neutron flux monitoring device, there are disposed a neutron flux measuring means for outputting signals in accordance with the intensity of neutron fluxes, a calculation means for calculating a self power density spectrum at a frequency band suitable to an object to be measured based on the output of the neutron flux measuring means, an alarm set value generation means for outputting an alarm set value as a comparative reference, and an alarm judging means for comparing the alarm set value with the outputted value of the calculation means to judge requirement of generating an alarm and generate an alarm in accordance with the result of the judgement. Namely, the time-series of neutron flux signals is put to fourier transformation for a predetermined period of time by the calculation means, and from each of square sums for real number component and imaginary number component for each of the frequencies, a self power density spectrum in the frequency band suitable to the object to be measured is calculated. Then, when the set reference value is exceeded, an alarm is generated. This can reliably prevent generation of erroneous alarm due to neutron flux noises and can accurately generate an alarm at an appropriate time. (N.H.)

  16. Coherent states on Hilbert modules

    International Nuclear Information System (INIS)

    Ali, S Twareque; Bhattacharyya, T; Roy, S S

    2011-01-01

    We generalize the concept of coherent states, traditionally defined as special families of vectors on Hilbert spaces, to Hilbert modules. We show that Hilbert modules over C*-algebras are the natural settings for a generalization of coherent states defined on Hilbert spaces. We consider those Hilbert C*-modules which have a natural left action from another C*-algebra, say A. The coherent states are well defined in this case and they behave well with respect to the left action by A. Certain classical objects like the Cuntz algebra are related to specific examples of coherent states. Finally we show that coherent states on modules give rise to a completely positive definite kernel between two C*-algebras, in complete analogy to the Hilbert space situation. Related to this, there is a dilation result for positive operator-valued measures, in the sense of Naimark. A number of examples are worked out to illustrate the theory. Some possible physical applications are also mentioned.

  17. Progress in coherent laser radar

    Science.gov (United States)

    Vaughan, J. M.

    1986-01-01

    Considerable progress with coherent laser radar has been made over the last few years, most notably perhaps in the available range of high performance devices and components and the confidence with which systems may now be taken into the field for prolonged periods of operation. Some of this increasing maturity was evident at the 3rd Topical Meeting on Coherent Laser Radar: Technology and Applications. Topics included in discussions were: mesoscale wind fields, nocturnal valley drainage and clear air down bursts; airborne Doppler lidar studies and comparison of ground and airborne wind measurement; wind measurement over the sea for comparison with satellite borne microwave sensors; transport of wake vortices at airfield; coherent DIAL methods; a newly assembled Nd-YAG coherent lidar system; backscatter profiles in the atmosphere and wavelength dependence over the 9 to 11 micrometer region; beam propagation; rock and soil classification with an airborne 4-laser system; technology of a global wind profiling system; target calibration; ranging and imaging with coherent pulsed and CW system; signal fluctuations and speckle. Some of these activities are briefly reviewed.

  18. Coherent states in quantum physics

    CERN Document Server

    Gazeau, Jean-Pierre

    2009-01-01

    This self-contained introduction discusses the evolution of the notion of coherent states, from the early works of Schrödinger to the most recent advances, including signal analysis. An integrated and modern approach to the utility of coherent states in many different branches of physics, it strikes a balance between mathematical and physical descriptions.Split into two parts, the first introduces readers to the most familiar coherent states, their origin, their construction, and their application and relevance to various selected domains of physics. Part II, mostly based on recent original results, is devoted to the question of quantization of various sets through coherent states, and shows the link to procedures in signal analysis. Title: Coherent States in Quantum Physics Print ISBN: 9783527407095 Author(s): Gazeau, Jean-Pierre eISBN: 9783527628292 Publisher: Wiley-VCH Dewey: 530.12 Publication Date: 23 Sep, 2009 Pages: 360 Category: Science, Science: Physics LCCN: Language: English Edition: N/A LCSH:

  19. Coherent phonon optics in a chip with an electrically controlled active device.

    Science.gov (United States)

    Poyser, Caroline L; Akimov, Andrey V; Campion, Richard P; Kent, Anthony J

    2015-02-05

    Phonon optics concerns operations with high-frequency acoustic waves in solid media in a similar way to how traditional optics operates with the light beams (i.e. photons). Phonon optics experiments with coherent terahertz and sub-terahertz phonons promise a revolution in various technical applications related to high-frequency acoustics, imaging, and heat transport. Previously, phonon optics used passive methods for manipulations with propagating phonon beams that did not enable their external control. Here we fabricate a phononic chip, which includes a generator of coherent monochromatic phonons with frequency 378 GHz, a sensitive coherent phonon detector, and an active layer: a doped semiconductor superlattice, with electrical contacts, inserted into the phonon propagation path. In the experiments, we demonstrate the modulation of the coherent phonon flux by an external electrical bias applied to the active layer. Phonon optics using external control broadens the spectrum of prospective applications of phononics on the nanometer scale.

  20. Experimental study of coherence vortices: Local properties of phase singularities in a spatial coherence function

    DEFF Research Database (Denmark)

    Wang, W.; Duan, Z.H.; Hanson, Steen Grüner

    2006-01-01

    By controlling the irradiance of an extended quasimonochromatic, spatially incoherent source, an optical field is generated that exhibits spatial coherence with phase singularities, called coherence vortices. A simple optical geometry for direct visualization of coherence vortices is proposed, an...

  1. Flux nucleation in the current-induced resistive state of a constricted type I superconductor

    International Nuclear Information System (INIS)

    Selig, K.P.; Huebener, R.P.

    1981-01-01

    The current-induced resistive state in a constricted type I superconductor is characterized by a train of flux tubes traversing the sample perpendicular to the direction of the applied current following its nucleation at the sample edge. The temporal structure of the nucleation process can be investigated by attempting to synchronize this process with small periodic current pulses superimposed on the direct bias current. The resistive dc voltage is then to be measured as a function of the pulse parameters such as frequency and width. We have performed such experiments at 4.2 K on constricted Pb films of 6--8 μm thickness and 100 μm width. Simultaneously with the electrical measurements the dynamic behavior of the flux tubes was directly observed using a stroboscopic magnetooptical method for magnetic flux detection. Our electrical measurements clearly show how the size of the nucleated flux tubes varies with the direct bias current and the nucleation frequency. The positive wall energy in the Pb films results in a lower limit for this size as expected. The influence of the preceding flux tubes still existing within the constriction upon the flux nucleation process is revealed in detail. All observations can be understood from a consideration of the energy balance during the flux nucleation process

  2. EDITORIAL: Coherent Control

    Science.gov (United States)

    Fielding, Helen; Shapiro, Moshe; Baumert, Thomas

    2008-04-01

    Quantum mechanics, though a probabilistic theory, gives a 'deterministic' answer to the question of how the present determines the future. In essence, in order to predict future probabilities, we need to (numerically) propagate the time-dependent Schrödinger equation from the present to the future. It is interesting to note that classical mechanics of macroscopic bodies, though reputed to be a deterministic theory, does not allow, due to chaos (which unfortunately is more prevalent than integrability), such clear insights into the future. In contrast, small (e.g., atomic, molecular and photonic) systems which are best understood using the tools of quantum mechanics, do not suffer from chaos, rendering the prediction of the probability-distributions of future events possible. The field of quantum control deals with an important modification of this task, namely, it asks: given a wave function in the present, what dynamics, i.e. what Hamiltonian, guarantees a desired outcome or 'objective' in the future? In practice one may achieve this goal of modifying and finding the desired Hamiltonian by introducing external fields, e.g. laser light. It is then possible to reach the objective in a 'trial-and-error' fashion, performed either numerically or in the laboratory. We can guess or build a Hamiltonian, do an experiment, or propagate the initial wave function to the future, compare the result with the desirable objective, and correct the guess for the Hamiltonian until satisfactory agreement with the objective is reached. A systematic way of executing this procedure is the sub-field called 'optimal control'. The trial-and-error method is often very time consuming and rarely provides mechanistic insight. There are situations where analytical solutions exist, rendering the control strategies more transparent. This is especially so when one can identify quantum interferences as the heart of quantum control, the essence of the field called 'coherent control'. The experience

  3. Coherent Waves in Seismic Researches

    Science.gov (United States)

    Emanov, A.; Seleznev, V. S.

    2013-05-01

    Development of digital processing algorithms of seismic wave fields for the purpose of useful event picking to study environment and other objects is the basis for the establishment of new seismic techniques. In the submitted paper a fundamental property of seismic wave field coherence is used. The authors extended conception of coherence types of observed wave fields and devised a technique of coherent component selection from observed wave field. Time coherence and space coherence are widely known. In this paper conception "parameter coherence" has been added. The parameter by which wave field is coherent can be the most manifold. The reason is that the wave field is a multivariate process described by a set of parameters. Coherence in the first place means independence of linear connection in wave field of parameter. In seismic wave fields, recorded in confined space, in building-blocks and stratified mediums time coherent standing waves are formed. In prospecting seismology at observation systems with multiple overlapping head waves are coherent by parallel correlation course or, in other words, by one measurement on generalized plane of observation system. For detail prospecting seismology at observation systems with multiple overlapping on basis of coherence property by one measurement of area algorithms have been developed, permitting seismic records to be converted to head wave time sections which have neither reflected nor other types of waves. Conversion in time section is executed on any specified observation base. Energy storage of head waves relative to noise on basis of multiplicity of observation system is realized within area of head wave recording. Conversion on base below the area of wave tracking is performed with lack of signal/noise ratio relative to maximum of this ratio, fit to observation system. Construction of head wave time section and dynamic plots a basis of automatic processing have been developed, similar to CDP procedure in method of

  4. The Open Flux Problem

    Science.gov (United States)

    Linker, J. A.; Caplan, R. M.; Downs, C.; Riley, P.; Mikic, Z.; Lionello, R.; Henney, C. J.; Arge, C. N.; Liu, Y.; Derosa, M. L.; Yeates, A.; Owens, M. J.

    2017-10-01

    The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.

  5. The Open Flux Problem

    Energy Technology Data Exchange (ETDEWEB)

    Linker, J. A.; Caplan, R. M.; Downs, C.; Riley, P.; Mikic, Z.; Lionello, R. [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Henney, C. J. [Air Force Research Lab/Space Vehicles Directorate, 3550 Aberdeen Avenue SE, Kirtland AFB, NM (United States); Arge, C. N. [Science and Exploration Directorate, NASA/GSFC, Greenbelt, MD 20771 (United States); Liu, Y. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Derosa, M. L. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street B/252, Palo Alto, CA 94304 (United States); Yeates, A. [Department of Mathematical Sciences, Durham University, Durham, DH1 3LE (United Kingdom); Owens, M. J., E-mail: linkerj@predsci.com [Space and Atmospheric Electricity Group, Department of Meteorology, University of Reading, Earley Gate, P.O. Box 243, Reading RG6 6BB (United Kingdom)

    2017-10-10

    The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun’s photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full-disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes (CHs) observed in emission and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both magnetohydrodynamic and potential field source surface solutions using 14 different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding 2010 July. We have found that for all of the model/map combinations, models that have CH areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than CHs observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected CHs for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun’s magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission.

  6. Coherent states for quadratic Hamiltonians

    International Nuclear Information System (INIS)

    Contreras-Astorga, Alonso; Fernandez C, David J; Velazquez, Mercedes

    2011-01-01

    The coherent states for a set of quadratic Hamiltonians in the trap regime are constructed. A matrix technique which allows us to directly identify the creation and annihilation operators will be presented. Then, the coherent states as simultaneous eigenstates of the annihilation operators will be derived, and will be compared with those attained through the displacement operator method. The corresponding wavefunction will be found, and a general procedure for obtaining several mean values involving the canonical operators in these states will be described. The results will be illustrated through the asymmetric Penning trap.

  7. Coherent γ-ray production

    International Nuclear Information System (INIS)

    Bertolotti, M.; Sibilia, C.

    1985-01-01

    In this article the authors discuss a new approach for developing a coherent source of γ-rays. They offer a completely different scheme for development of the source that should overcome most of the problems encountered in ''classical γ-ray lasers,'' and in which the use of inverse Compton scattering of laser radiation onto a relativistic electron beam is made. This kind of interaction has been used to obtain γ-ray photons with good polarization and monochromaticity properties. The authors describe a new geometry of interaction which allows one to obtain coherent emission

  8. Meromorphic flux compactification

    Energy Technology Data Exchange (ETDEWEB)

    Damian, Cesar [Departamento de Ingeniería Mecánica, Universidad de Guanajuato,Carretera Salamanca-Valle de Santiago Km 3.5+1.8 Comunidad de Palo Blanco,Salamanca (Mexico); Loaiza-Brito, Oscar [Departamento de Física, Universidad de Guanajuato,Loma del Bosque No. 103 Col. Lomas del Campestre C.P 37150 León, Guanajuato (Mexico)

    2017-04-26

    We present exact solutions of four-dimensional Einstein’s equations related to Minkoswki vacuum constructed from Type IIB string theory with non-trivial fluxes. Following https://www.doi.org/10.1007/JHEP02(2015)187; https://www.doi.org/10.1007/JHEP02(2015)188 we study a non-trivial flux compactification on a fibered product by a four-dimensional torus and a two-dimensional sphere punctured by 5- and 7-branes. By considering only 3-form fluxes and the dilaton, as functions on the internal sphere coordinates, we show that these solutions correspond to a family of supersymmetric solutions constructed by the use of G-theory. Meromorphicity on functions constructed in terms of fluxes and warping factors guarantees that flux and 5-brane contributions to the scalar curvature vanish while fulfilling stringent constraints as tadpole cancelation and Bianchi identities. Different Einstein’s solutions are shown to be related by U-dualities. We present three supersymmetric non-trivial Minkowski vacuum solutions and compute the corresponding soft terms. We also construct a non-supersymmetric solution and study its stability.

  9. Meromorphic flux compactification

    International Nuclear Information System (INIS)

    Damian, Cesar; Loaiza-Brito, Oscar

    2017-01-01

    We present exact solutions of four-dimensional Einstein’s equations related to Minkoswki vacuum constructed from Type IIB string theory with non-trivial fluxes. Following https://www.doi.org/10.1007/JHEP02(2015)187; https://www.doi.org/10.1007/JHEP02(2015)188 we study a non-trivial flux compactification on a fibered product by a four-dimensional torus and a two-dimensional sphere punctured by 5- and 7-branes. By considering only 3-form fluxes and the dilaton, as functions on the internal sphere coordinates, we show that these solutions correspond to a family of supersymmetric solutions constructed by the use of G-theory. Meromorphicity on functions constructed in terms of fluxes and warping factors guarantees that flux and 5-brane contributions to the scalar curvature vanish while fulfilling stringent constraints as tadpole cancelation and Bianchi identities. Different Einstein’s solutions are shown to be related by U-dualities. We present three supersymmetric non-trivial Minkowski vacuum solutions and compute the corresponding soft terms. We also construct a non-supersymmetric solution and study its stability.

  10. Flux Pinning in Superconductors

    CERN Document Server

    Matsushita, Teruo

    2007-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  11. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Goto, Yasushi; Mitsubori, Minehisa; Ohashi, Kazunori.

    1997-01-01

    The present invention provides a neutron flux monitoring device for preventing occurrence of erroneous reactor scram caused by the elevation of the indication of a start region monitor (SRM) due to a factor different from actual increase of neutron fluxes. Namely, judgement based on measured values obtained by a pulse counting method and a judgment based on measured values obtained by a Cambel method are combined. A logic of switching neutron flux measuring method to be used for monitoring, namely, switching to an intermediate region when both of the judgements are valid is adopted. Then, even if the indication value is elevated based on the Cambel method with no increase of the counter rate in a neutron source region, the switching to the intermediate region is not conducted. As a result, erroneous reactor scram such as 'shorter reactor period' can be avoided. (I.S.)

  12. Formulation of the moiré patterns formed by superimposing of gratings consisting topological defects: moiré technique as a tool in singular optics detections

    International Nuclear Information System (INIS)

    Rasouli, Saifollah; Yeganeh, Mohammad

    2015-01-01

    The use of moiré pattern of superimposition of linear forked gratings (LFGs) and Fresnel zone plates (ZPs) has already been reported for study of different physical effects. In spite of a considerable number of applications, there is no comprehensive formulation for this kind of moiré pattern. In this work, we introduce a new family of ZPs containing topological defects that we named defected ZP (DZP) and we present a very simple, uniform, and comprehensive formulation for the moiré pattern of superimposition of two LFGs, two DZPs, and superimposition of an LFG on a DZP, using the reciprocal vector approach. For the case of the two LFGs superimposition, we show that the resulting moiré pattern has a starlike shape or is a large-scale LFG pattern. In the case in which two DZPs are superimposed, we show that the resulting moiré pattern has three general forms: large-scale DZP pattern, starlike pattern, and large-scale LFG pattern. In the superimposition of an LFG on a DZP, in special conditions a new spiral ZP having a topological defect is produced in which its defect number related to the superimposed gratings structures. The presented formulation has potential applications in singular optics measurements. (paper)

  13. Coherent control of quantum dots

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Lodahl, Peter; Hvam, Jørn Märcher

    In recent years much effort has been devoted to the use of semiconductor quantum dotsystems as building blocks for solid-state-based quantum logic devices. One importantparameter for such devices is the coherence time, which determines the number ofpossible quantum operations. From earlier...

  14. Coherent Radiation of Electron Cloud

    International Nuclear Information System (INIS)

    Heifets, S.

    2004-01-01

    The electron cloud in positron storage rings is pinched when a bunch passes by. For short bunches, the radiation due to acceleration of electrons of the cloud is coherent. Detection of such radiation can be used to measure the density of the cloud. The estimate of the power and the time structure of the radiated signal is given in this paper

  15. Asymmetric Penning trap coherent states

    International Nuclear Information System (INIS)

    Contreras-Astorga, Alonso; Fernandez, David J.

    2010-01-01

    By using a matrix technique, which allows to identify directly the ladder operators, the coherent states of the asymmetric Penning trap are derived as eigenstates of the appropriate annihilation operators. They are compared with those obtained through the displacement operator method.

  16. Coherent dynamics of plasma mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Thaury, C; George, H; Quere, F; Monot, P; Martin, Ph [CEA, DSM, IRAMIS, Serv Photons Atomes and Mol, F-91191 Gif Sur Yvette, (France); Loch, R [Univ Twente, Laser Phys and Nonlinear Opt Grp, Fac Sci and Technol, MESA Inst Nanotechnol, NL-7500 AE Enschede, (Netherlands); Geindre, J P [Ecole Polytech, Lab Pour Utilisat Lasers Intenses, CNRS, F-91128 Palaiseau, (France)

    2008-07-01

    Coherent ultrashort X-ray pulses provide new ways to probe matter and its ultrafast dynamics. One of the promising paths to generate these pulses consists of using a nonlinear interaction with a system to strongly and periodically distort the waveform of intense laser fields, and thus produce high-order harmonics. Such distortions have so far been induced by using the nonlinear polarizability of atoms, leading to the production of atto-second light bursts, short enough to study the dynamics of electrons in matter. Shorter and more intense atto-second pulses, together with higher harmonic orders, are expected by reflecting ultra intense laser pulses on a plasma mirror - a dense (approximate to 10{sup 23} electrons cm{sup -3}) plasma with a steep interface. However, short-wavelength-light sources produced by such plasmas are known to generally be incoherent. In contrast, we demonstrate that like in usual low-intensity reflection, the coherence of the light wave is preserved during harmonic generation on plasma mirrors. We then exploit this coherence for interferometric measurements and thus carry out a first study of the laser-driven coherent dynamics of the plasma electrons. (authors)

  17. Optimally cloned binary coherent states

    DEFF Research Database (Denmark)

    Mueller, C. R.; Leuchs, G.; Marquardt, Ch

    2017-01-01

    their quantum-optimal clones. We analyze the Wigner function and the cumulants of the clones, and we conclude that optimal cloning of binary coherent states requires a nonlinearity above second order. We propose several practical and near-optimal cloning schemes and compare their cloning fidelity to the optimal...

  18. Coherent beam-beam effect

    International Nuclear Information System (INIS)

    Chao, A.W.; Keil, E.

    1979-06-01

    The stability of the coherent beam-beam effect between rigid bunches is studied analytically and numerically for a linear force by evaluating eigenvalues. For a realistic force, the stability is investigated by following the bunches for many revolutions. 4 refs., 13 figs., 2 tabs

  19. Optical coherent control in semiconductors

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher

    2001-01-01

    of quantum control including the recent applications to semiconductors and nanostructures. We study the influence of inhomogeneous broadening in semiconductors on CC results. Photoluminescence (PL) and the coherent emission in four-wave mixing (FWM) is recorded after resonant excitation with phase...

  20. Dialogue Coherence: A Generation Framework

    NARCIS (Netherlands)

    Beun, R.J.; Eijk, R.M. van

    2007-01-01

    This paper presents a framework for the generation of coherent elementary conversational sequences at the speech act level. We will embrace the notion of a cooperative dialogue game in which two players produce speech acts to transfer relevant information with respect to their commitments.

  1. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Honda, M.; Kasahara, K.; Hidaka, K.; Midorikawa, S.

    1990-02-01

    A detailed Monte Carlo simulation of neutrino fluxes of atmospheric origin is made taking into account the muon polarization effect on neutrinos from muon decay. We calculate the fluxes with energies above 3 MeV for future experiments. There still remains a significant discrepancy between the calculated (ν e +antiν e )/(ν μ +antiν μ ) ratio and that observed by the Kamiokande group. However, the ratio evaluated at the Frejus site shows a good agreement with the data. (author)

  2. Coherence for vectorial waves and majorization

    OpenAIRE

    Luis, Alfredo

    2016-01-01

    We show that majorization provides a powerful approach to the coherence conveyed by partially polarized transversal electromagnetic waves. Here we present the formalism, provide some examples and compare with standard measures of polarization and coherence of vectorial waves.

  3. Electron beam instrumentation techniques using coherent radiation

    International Nuclear Information System (INIS)

    Wang, D.X.

    1997-01-01

    Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed

  4. On P-coherent endomorphism rings

    Indian Academy of Sciences (India)

    A ring is called right -coherent if every principal right ideal is finitely presented. Let M R be a right -module. We study the -coherence of the endomorphism ring of M R . It is shown that is a right -coherent ring if and only if every endomorphism of M R has a pseudokernel in add M R ; S is a left -coherent ring if and ...

  5. Active control of divertor heat and particle fluxes in EAST towards advanced steady state operations

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L., E-mail: lwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Dalian University of Technology, Dalian 116024 (China); Guo, H.Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); General Atomics, P. O. Box 85608, San Diego, CA 92186 (United States); Li, J.; Wan, B.N.; Gong, X.Z.; Zhang, X.D.; Hu, J.S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Liang, Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Association EURATOM-FZJ, D-52425 Jülich (Germany); Xu, G.S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zou, X.L. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Loarte, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Maingi, R.; Menard, J.E. [Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States); Luo, G.N.; Gao, X.; Hu, L.Q.; Gan, K.F.; Liu, S.C.; Wang, H.Q.; Chen, R. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); and others

    2015-08-15

    Significant progress has been made in EAST towards advanced steady state operations by active control of divertor heat and particle fluxes. Many innovative techniques have been developed to mitigate transient ELM and stationary heat fluxes on the divertor target plates. It has been found that lower hybrid current drive (LHCD) can lead to edge plasma ergodization, striation of the stationary heat flux and lower ELM transient heat and particle fluxes. With multi-pulse supersonic molecular beam injection (SMBI) to quantitatively regulate the divertor particle flux, the divertor power footprint pattern can be actively modified. H-modes have been extended over 30 s in EAST with the divertor peak heat flux and the target temperature being controlled well below 2 MW/m{sup 2} and 250 °C, respectively, by integrating these new methods, coupled with advanced lithium wall conditioning and internal divertor pumping, along with an edge coherent mode to provide continuous particle and power exhaust.

  6. On Radar Resolution in Coherent Change Detection.

    Energy Technology Data Exchange (ETDEWEB)

    Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    It is commonly observed that resolution plays a role in coherent change detection. Although this is the case, the relationship of the resolution in coherent change detection is not yet defined . In this document, we present an analytical method of evaluating this relationship using detection theory. Specifically we examine the effect of resolution on receiver operating characteristic curves for coherent change detection.

  7. Some remarks on quantum coherence theory

    International Nuclear Information System (INIS)

    Burzynski, A.

    1982-01-01

    This paper is devoted to the basic topics connected with coherence in quantum mechanics and quantum theory of radiation. In particular the formalism of the normal ordered coherence functions in cases of one and many degrees of freedom is described in detail. A few examples illustrate the analysis of the coherence properties of the various quantum states of the field of radiation. (author)

  8. Coherence-driven argumentation to norm consensus

    NARCIS (Netherlands)

    Joseph, S.; Prakken, H.

    2009-01-01

    In this paper coherence-based models are proposed as an alternative to logic-based BDI and argumentation models for the reasoning of normative agents. A model is provided for how two coherence-based agents can deliberate on how to regulate a domain of interest. First a deductive coherence model

  9. Coherent states for polynomial su(2) algebra

    International Nuclear Information System (INIS)

    Sadiq, Muhammad; Inomata, Akira

    2007-01-01

    A class of generalized coherent states is constructed for a polynomial su(2) algebra in a group-free manner. As a special case, the coherent states for the cubic su(2) algebra are discussed. The states so constructed reduce to the usual SU(2) coherent states in the linear limit

  10. Radiation flux measuring device

    International Nuclear Information System (INIS)

    Corte, E.; Maitra, P.

    1977-01-01

    A radiation flux measuring device is described which employs a differential pair of transistors, the output of which is maintained constant, connected to a radiation detector. Means connected to the differential pair produce a signal representing the log of the a-c component of the radiation detector, thereby providing a signal representing the true root mean square logarithmic output. 3 claims, 2 figures

  11. Soluble organic nutrient fluxes

    Science.gov (United States)

    Robert G. Qualls; Bruce L. Haines; Wayne Swank

    2014-01-01

    Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

  12. Flux vacua and supermanifolds

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, Pietro Antonio [CERN, Theory Unit, CH-1211 Geneva, 23 (Switzerland); Marescotti, Matteo [Dipartimento di Fisica Teorica, Universita di Torino, Via Giuria 1, I-10125, Turin (Italy)

    2007-01-15

    As been recently pointed out, physically relevant models derived from string theory require the presence of non-vanishing form fluxes besides the usual geometrical constraints. In the case of NS-NS fluxes, the Generalized Complex Geometry encodes these informations in a beautiful geometrical structure. On the other hand, the R-R fluxes call for supergeometry as the underlying mathematical framework. In this context, we analyze the possibility of constructing interesting supermanifolds recasting the geometrical data and RR fluxes. To characterize these supermanifolds we have been guided by the fact topological strings on supermanifolds require the super-Ricci flatness of the target space. This can be achieved by adding to a given bosonic manifold enough anticommuting coordinates and new constraints on the bosonic sub-manifold. We study these constraints at the linear and non-linear level for a pure geometrical setting and in the presence of p-form field strengths. We find that certain spaces admit several super-extensions and we give a parameterization in a simple case of d bosonic coordinates and two fermionic coordinates. In addition, we comment on the role of the RR field in the construction of the super-metric. We give several examples based on supergroup manifolds and coset supermanifolds.

  13. Flux vacua and supermanifolds

    International Nuclear Information System (INIS)

    Grassi, Pietro Antonio; Marescotti, Matteo

    2007-01-01

    As been recently pointed out, physically relevant models derived from string theory require the presence of non-vanishing form fluxes besides the usual geometrical constraints. In the case of NS-NS fluxes, the Generalized Complex Geometry encodes these informations in a beautiful geometrical structure. On the other hand, the R-R fluxes call for supergeometry as the underlying mathematical framework. In this context, we analyze the possibility of constructing interesting supermanifolds recasting the geometrical data and RR fluxes. To characterize these supermanifolds we have been guided by the fact topological strings on supermanifolds require the super-Ricci flatness of the target space. This can be achieved by adding to a given bosonic manifold enough anticommuting coordinates and new constraints on the bosonic sub-manifold. We study these constraints at the linear and non-linear level for a pure geometrical setting and in the presence of p-form field strengths. We find that certain spaces admit several super-extensions and we give a parameterization in a simple case of d bosonic coordinates and two fermionic coordinates. In addition, we comment on the role of the RR field in the construction of the super-metric. We give several examples based on supergroup manifolds and coset supermanifolds

  14. Atmospheric neutrino fluxes

    International Nuclear Information System (INIS)

    Perkins, D.H.

    1984-01-01

    The atmospheric neutrino fluxes, which are responsible for the main background in proton decay experiments, have been calculated by two independent methods. There are discrepancies between the two sets of results regarding latitude effects and up-down asymmetries, especially for neutrino energies Esub(ν) < 1 GeV. (author)

  15. Flux scaling: Ultimate regime

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Flux scaling: Ultimate regime. With the Nusselt number and the mixing length scales, we get the Nusselt number and Reynolds number (w'd/ν) scalings: and or. and. scaling expected to occur at extremely high Ra Rayleigh-Benard convection. Get the ultimate regime ...

  16. Quantum transport in coupled resonators enclosed synthetic magnetic flux

    International Nuclear Information System (INIS)

    Jin, L.

    2016-01-01

    Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov–Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms. -- Highlights: •The light transport is investigated through ring array of coupled resonators enclosed synthetic magnetic field. •Aharonov–Bohm ring interferometer of arbitrary configuration is investigated. •The half-integer magnetic flux quantum leads to destructive interference and transmission zeros for two-arm at equal length. •Complete transmission is available via tuning synthetic magnetic flux.

  17. Phase retrieval from coherent soft X-ray optics

    International Nuclear Information System (INIS)

    Peele, A.G.; Mancuso, A.P.; Tran, C.Q.; Paterson, D.; McNulty, I.; Hayes, J.P.; Nugent, K.A.

    2005-01-01

    We have recently probed the coherence of soft X-ray flux from a third generation synchrotron source [D. Paterson, B.E. Allman, P.J. McMahon, J. Lin, N. Moldovan, K.A. Nugent, I. McNulty, C.T. Chantler, C.C. Retsch, T.H.K. Irving, D.C. Mancini, Opt. Commun. 195 (2001) 79; C.Q. Tran, A.G. Peele, D. Paterson, A. Roberts, I. McNulty, K.A. Nugent, Opt. Lett. 30 (2005) 204.]. The 1-2 keV radiation exhibits transverse coherence lengths of 60 μm, which means that coherent optical effects may be observed in reasonably sized objects. We present experimental results demonstrating the creation of a phase singularity in a synchrotron beam by passing the beam through a phase mask at similarly low X-ray energies. This complements our earlier work at higher energies and demonstrates that we can now produce phase singularities across a range of energies where we have tested certain intensity-based phase recovery methods. These methods fail when the field contains phase singularities. We describe the X-ray optical vortex and outline its use as a pathological test object for phase retrieval methods. We also present recent progress towards overcoming the problem of phase retrieval in singular optics

  18. Path integrals and coherent states of SU(2) and SU(1,1)

    CERN Document Server

    Inomata, Akira; Kuratsuji, Hiroshi

    1992-01-01

    The authors examine several topical subjects, commencing with a general introduction to path integrals in quantum mechanics and the group theoretical backgrounds for path integrals. Applications of harmonic analysis, polar coordinate formulation, various techniques and path integrals on SU(2) and SU(1, 1) are discussed. Soluble examples presented include particle-flux system, a pulsed oscillator, magnetic monopole, the Coulomb problem in curved space and others.The second part deals with the SU(2) coherent states and their applications. Construction and generalization of the SU(2) coherent sta

  19. Flux-induced Nernst effect in low-dimensional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Jorge, E-mail: jorge.berger@braude.ac.il

    2017-02-15

    Highlights: • The Nernst effect tells us that the presence of a magnetic field and a temperature gradient in a conductor yields a transverse voltage. • The Nernst effect in superconductors, especially above their critical temperature, has been a hot topic of research during the last decades. • I predict a new effect in which a transverse voltage arises, not because of the magnetic field, but rather because of the magnetic flux enclosed by a loop with non-uniform temperature. - Abstract: A method is available that enables consistent study of the stochastic behavior of a system that obeys purely diffusive evolution equations. This method has been applied to a superconducting loop with nonuniform temperature, with average temperature close to T{sub c}. It is found that a flux-dependent average potential difference arises along the loop, proportional to the temperature gradient and most pronounced in the direction perpendicular to this gradient. The largest voltages were obtained for fluxes close to 0.3Φ{sub 0}, average temperatures slightly below the critical temperature, thermal coherence length of the order of the perimeter of the ring, BCS coherence length that is not negligible in comparison to the thermal coherence length, and short inelastic scattering time. This effect is entirely due to thermal fluctuations. It differs essentially from the usual Nernst effect in bulk superconductors, that is induced by magnetic field rather than by magnetic flux. We also study the effect of confinement in a 2D mesoscopic film.

  20. Coherence in electron energy loss spectrometry

    International Nuclear Information System (INIS)

    Schattschneider, P.; Werner, W.S.M.

    2005-01-01

    Coherence effects in electron energy loss spectrometry (EELS) and in energy filtering are largely neglected although they occur frequently due to Bragg scattering in crystals. We discuss how coherence in the inelastically scattered wave field can be described by the mixed dynamic form factor (MDFF), and how it relates to the density matrix of the scattered electrons. Among the many aspects of 'inelastic coherence' are filtered high-resolution images, dipole-forbidden transitions, coherence in plasma excitations, errors in chemical microanalysis, coherent double plasmons, and circular dichroism

  1. Characterisation of dispersive systems using a coherer

    Directory of Open Access Journals (Sweden)

    Nikolić Pantelija M.

    2002-01-01

    Full Text Available The possibility of characterization of aluminium powders using a horizontal coherer has been considered. Al powders of known dimension were treated with a high frequency electromagnetic field or with a DC electric field, which were increased until a dielectric breakdown occurred. Using a multifunctional card PC-428 Electronic Design and a suitable interface between the coherer and PC, the activation time of the coherer was measured as a function of powder dimension and the distance between the coherer electrodes. It was also shown that the average dimension of powders of unknown size could be determined using the coherer.

  2. Quantum coherence and correlations in quantum system

    Science.gov (United States)

    Xi, Zhengjun; Li, Yongming; Fan, Heng

    2015-01-01

    Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we first give an uncertainty-like expression relating the coherence and the entropy of quantum system. This finding allows us to discuss the relations between the entanglement and the coherence. Further, we discuss in detail the relations among the coherence, the discord and the deficit in the bipartite quantum system. We show that, the one-way quantum deficit is equal to the sum between quantum discord and the relative entropy of coherence of measured subsystem. PMID:26094795

  3. Theory of coherent resonance energy transfer

    International Nuclear Information System (INIS)

    Jang, Seogjoo; Cheng, Y.-C.; Reichman, David R.; Eaves, Joel D.

    2008-01-01

    A theory of coherent resonance energy transfer is developed combining the polaron transformation and a time-local quantum master equation formulation, which is valid for arbitrary spectral densities including common modes. The theory contains inhomogeneous terms accounting for nonequilibrium initial preparation effects and elucidates how quantum coherence and nonequilibrium effects manifest themselves in the coherent energy transfer dynamics beyond the weak resonance coupling limit of the Foerster and Dexter (FD) theory. Numerical tests show that quantum coherence can cause significant changes in steady state donor/acceptor populations from those predicted by the FD theory and illustrate delicate cooperation of nonequilibrium and quantum coherence effects on the transient population dynamics.

  4. The global coherence initiative: creating a coherent planetary standing wave.

    Science.gov (United States)

    McCraty, Rollin; Deyhle, Annette; Childre, Doc

    2012-03-01

    The much anticipated year of 2012 is now here. Amidst the predictions and cosmic alignments that many are aware of, one thing is for sure: it will be an interesting and exciting year as the speed of change continues to increase, bringing both chaos and great opportunity. One benchmark of these times is a shift in many people from a paradigm of competition to one of greater cooperation. All across the planet, increasing numbers of people are practicing heart-based living, and more groups are forming activities that support positive change and creative solutions for manifesting a better world. The Global Coherence Initiative (GCI) is a science-based, co-creative project to unite people in heart-focused care and intention. GCI is working in concert with other initiatives to realize the increased power of collective intention and consciousness. The convergence of several independent lines of evidence provides strong support for the existence of a global information field that connects all living systems and consciousness. Every cell in our bodies is bathed in an external and internal environment of fluctuating invisible magnetic forces that can affect virtually every cell and circuit in biological systems. Therefore, it should not be surprising that numerous physiological rhythms in humans and global collective behaviors are not only synchronized with solar and geomagnetic activity, but disruptions in these fields can create adverse effects on human health and behavior. The most likely mechanism for explaining how solar and geomagnetic influences affect human health and behavior are a coupling between the human nervous system and resonating geomagnetic frequencies, called Schumann resonances, which occur in the earth-ionosphere resonant cavity and Alfvén waves. It is well established that these resonant frequencies directly overlap with those of the human brain and cardiovascular system. If all living systems are indeed interconnected and communicate with each other

  5. Operational resource theory of total quantum coherence

    Science.gov (United States)

    Yang, Si-ren; Yu, Chang-shui

    2018-01-01

    Quantum coherence is an essential feature of quantum mechanics and is an important physical resource in quantum information. Recently, the resource theory of quantum coherence has been established parallel with that of entanglement. In the resource theory, a resource can be well defined if given three ingredients: the free states, the resource, the (restricted) free operations. In this paper, we study the resource theory of coherence in a different light, that is, we consider the total coherence defined by the basis-free coherence maximized among all potential basis. We define the distillable total coherence and the total coherence cost and in both the asymptotic regime and the single-copy regime show the reversible transformation between a state with certain total coherence and the state with the unit reference total coherence. Extensively, we demonstrate that the total coherence can also be completely converted to the total correlation with the equal amount by the free operations. We also provide the alternative understanding of the total coherence, respectively, based on the entanglement and the total correlation in a different way.

  6. Stochasticity induced by coherent wavepackets

    International Nuclear Information System (INIS)

    Fuchs, V.; Krapchev, V.; Ram, A.; Bers, A.

    1983-02-01

    We consider the momentum transfer and diffusion of electrons periodically interacting with a coherent longitudinal wavepacket. Such a problem arises, for example, in lower-hybrid current drive. We establish the stochastic threshold, the stochastic region δv/sub stoch/ in velocity space, the associated momentum transfer j, and the diffusion coefficient D. We concentrate principally on the weak-field regime, tau/sub autocorrelation/ < tau/sub bounce/

  7. Entropic cohering power in quantum operations

    Science.gov (United States)

    Xi, Zhengjun; Hu, Ming-Liang; Li, Yongming; Fan, Heng

    2018-02-01

    Coherence is a basic feature of quantum systems and a common necessary condition for quantum correlations. It is also an important physical resource in quantum information processing. In this paper, using relative entropy, we consider a more general definition of the cohering power of quantum operations. First, we calculate the cohering power of unitary quantum operations and show that the amount of distributed coherence caused by non-unitary quantum operations cannot exceed the quantum-incoherent relative entropy between system of interest and its environment. We then find that the difference between the distributed coherence and the cohering power is larger than the quantum-incoherent relative entropy. As an application, we consider the distributed coherence caused by purification.

  8. Design of a flux buffer based on the flux shuttle

    International Nuclear Information System (INIS)

    Gershenson, M.

    1991-01-01

    This paper discusses the design considerations for a flux buffer based on the flux-shuttle concept. Particular attention is given to the issues of flux popping, stability of operation and saturation levels for a large input. Modulation techniques used in order to minimize 1/f noise, in addition to offsets are also analyzed. Advantages over conventional approaches using a SQUID for a flux buffer are discussed. Results of computer simulations are presented

  9. Investigation of ionic movements during anodic oxidation of superimposed metallic layers by the use of Rutherford backscattering techniques and nuclear micro analysis

    International Nuclear Information System (INIS)

    Perriere, J.; Siejka, J.; Rigo, S.

    1980-01-01

    Nuclear micro-analysis by the direct observation of nuclear reactions and of backscattered particles was used to study ionic movements during the anodization of superimposed metallic films (M 1 -M 2 systems). It has been shown that the order of cations is largely preserved during the anodization of Ta-Nb or Al-Nb systems while it is inverted in the case of Nb-Ta and Nb-Al systems. These results are discussed in terms of differences in jump probabilities of atoms. The oxygen movements in these systems were studied by 18 O tracing techniques; the results suggest that a correlation exists between oxygen and cationic migration during anodic oxide growth. The discussion of these results in terms of microscopic transport mechanisms is based on a neighbour to neighbour type propagation process for cationic as well as oxygen movement. (author)

  10. Numerous Sinusoidal and Other EMF Phenomena, At Present and Former Native American Sites, May Be Superimposing Themselves onto Regional Power Grids.

    Science.gov (United States)

    Cadran, Lawrence R.; Mc Leod, Roger D.; Mc Leod, David M.

    2003-10-01

    Periodic electromagnetic field signals (EMF), sometimes noticeable as faint blue-light or other phenomena, frequently are also detected at sites associated with Native Americans. We first noticed this sort of information in the vicinity of Wendell, MA about fourteen years ago. Similar and other signals are apparent at Americas Stonehenge, AS, in North Salem, NH. Connecticut provided our first evidence of superposition of two such waves at the Gungywamp site north of Groton, CT. A Maine location first showed orthogonally oriented trajectories in neighborhoods formerly frequented by Molocket and Metallak and their relatives near Rumford and Rangeley, ME. Florida exhibits similar signals in the vicinity of Hollywood and at Miamis Tequesta instrument, as does a separate site in CT. Powerful thunderstorms in the vicinity of a stone serpent effigy in Ohio cause EMF pulsations. Such signals are possibly superimposing themselves onto power-grids, where frequency changes and system instabilities may occur, according to the elementary physics involved.

  11. Investigation of carbon cathode surface before and after the passage of combined dc vacuum arc with superimposed high-current arc pulses

    International Nuclear Information System (INIS)

    Zavaleyev, V.; Walkowicz, J.; Moszynski, D.

    2016-01-01

    The paper presents the results of studies of carbon cathode surface before and after the passage of the combined DC vacuum-arc with superimposed high-current arc pulses. Investigations of surface morphology of carbon cathode showed, that secondary nuclei of high-density are formed after passing of the combined DC-pulse vacuum-arc, which results in the formation of a globular structures. The phase structure analysis by Raman spectroscopy showed that even at a minimum operation time (5 s) of the combined DC-pulse vacuum-arc broadening of the peaks 1355 and 1583 cm-1 occurs, which means that the carbon cathode surface undergo phase transformation. Results obtained by XPS spectroscopy demonstrate that the globular structures formed on the cathode surface are composed of sp 3 -bonded carbon atoms and carbon-oxygen bonds.

  12. Quantum learning of coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Sentis, Gael [Universitat Autonoma de Barcelona, Fisica Teorica: Informacio i Fenomens Quantics, Barcelona (Spain); Guta, Madalin; Adesso, Gerardo [University of Nottingham, School of Mathematical Sciences, Nottingham (United Kingdom)

    2015-12-15

    We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our setting, a coherent light source is used to illuminate a memory cell and retrieve its encoded bit by determining the quantum state of the reflected signal. We consider a situation where the amplitude of the states produced by the source is not fully known, but instead this information is encoded in a large training set comprising many copies of the same coherent state. We show that an optimal global measurement, performed jointly over the signal and the training set, provides higher successful identification rates than any learning strategy based on first estimating the unknown amplitude by means of Gaussian measurements on the training set, followed by an adaptive discrimination procedure on the signal. By considering a simplified variant of the problem, we argue that this is the case even for non-Gaussian estimation measurements. Our results show that, even in absence of entanglement, collective quantum measurements yield an enhancement in the readout of classical information, which is particularly relevant in the operating regime of low-energy signals. (orig.)

  13. Coherent lattice vibrations in superconductors

    International Nuclear Information System (INIS)

    Kadin, Alan M.

    2008-01-01

    A recent analysis has shown that the pair wavefunction within the BCS theory may be represented in real-space as a spherical electronic orbital (on the scale of the coherence length ξ 0 ) coupled to a standing-wave lattice vibration with wavevector 2k F and a near-resonant phonon frequency. The present paper extends this picture to a coherent pattern of phonon standing-waves on the macroscopic scale, with electrons forming Bloch waves and an energy gap much like those in the classic band theory of crystals. These parallel planes form a diffractive waveguide permitting electron waves to traveling parallel to the planes, corresponding to lossless supercurrent. A similar picture may be extended to unconventional superconductors such as the cuprates, with an array of standing spin waves rather than phonons. Such coherent lattice vibrations should be universal indicators of the superconducting state, and should be observable below T c using X-ray and neutron diffraction techniques. Further implications of this picture are discussed

  14. Quantum learning of coherent states

    International Nuclear Information System (INIS)

    Sentis, Gael; Guta, Madalin; Adesso, Gerardo

    2015-01-01

    We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our setting, a coherent light source is used to illuminate a memory cell and retrieve its encoded bit by determining the quantum state of the reflected signal. We consider a situation where the amplitude of the states produced by the source is not fully known, but instead this information is encoded in a large training set comprising many copies of the same coherent state. We show that an optimal global measurement, performed jointly over the signal and the training set, provides higher successful identification rates than any learning strategy based on first estimating the unknown amplitude by means of Gaussian measurements on the training set, followed by an adaptive discrimination procedure on the signal. By considering a simplified variant of the problem, we argue that this is the case even for non-Gaussian estimation measurements. Our results show that, even in absence of entanglement, collective quantum measurements yield an enhancement in the readout of classical information, which is particularly relevant in the operating regime of low-energy signals. (orig.)

  15. Lobotomy of flux compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Dibitetto, Giuseppe [Institutionen för fysik och astronomi, University of Uppsala,Box 803, SE-751 08 Uppsala (Sweden); Guarino, Adolfo [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,Bern University, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Roest, Diederik [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4 9747 AG Groningen (Netherlands)

    2014-05-15

    We provide the dictionary between four-dimensional gauged supergravity and type II compactifications on T{sup 6} with metric and gauge fluxes in the absence of supersymmetry breaking sources, such as branes and orientifold planes. Secondly, we prove that there is a unique isotropic compactification allowing for critical points. It corresponds to a type IIA background given by a product of two 3-tori with SO(3) twists and results in a unique theory (gauging) with a non-semisimple gauge algebra. Besides the known four AdS solutions surviving the orientifold projection to N=4 induced by O6-planes, this theory contains a novel AdS solution that requires non-trivial orientifold-odd fluxes, hence being a genuine critical point of the N=8 theory.

  16. Physics of magnetic flux ropes

    Science.gov (United States)

    Russell, C. T.; Priest, E. R.; Lee, L. C.

    The present work encompasses papers on the structure, waves, and instabilities of magnetic flux ropes (MFRs), photospheric flux tubes (PFTs), the structure and heating of coronal loops, solar prominences, coronal mass ejections and magnetic clouds, flux ropes in planetary ionospheres, the magnetopause, magnetospheric field-aligned currents and flux tubes, and the magnetotail. Attention is given to the equilibrium of MFRs, resistive instability, magnetic reconnection and turbulence in current sheets, dynamical effects and energy transport in intense flux tubes, waves in solar PFTs, twisted flux ropes in the solar corona, an electrodynamical model of solar flares, filament cooling and condensation in a sheared magnetic field, the magnetopause, the generation of twisted MFRs during magnetic reconnection, ionospheric flux ropes above the South Pole, substorms and MFR structures, evidence for flux ropes in the earth magnetotail, and MFRs in 3D MHD simulations.

  17. From quantum coherence to quantum correlations

    Science.gov (United States)

    Sun, Yuan; Mao, Yuanyuan; Luo, Shunlong

    2017-06-01

    In quantum mechanics, quantum coherence of a state relative to a quantum measurement can be identified with the quantumness that has to be destroyed by the measurement. In particular, quantum coherence of a bipartite state relative to a local quantum measurement encodes quantum correlations in the state. If one takes minimization with respect to the local measurements, then one is led to quantifiers which capture quantum correlations from the perspective of coherence. In this vein, quantum discord, which quantifies the minimal correlations that have to be destroyed by quantum measurements, can be identified as the minimal coherence, with the coherence measured by the relative entropy of coherence. To advocate and formulate this idea in a general context, we first review coherence relative to Lüders measurements which extends the notion of coherence relative to von Neumann measurements (or equivalently, orthonomal bases), and highlight the observation that quantum discord arises as minimal coherence through two prototypical examples. Then, we introduce some novel measures of quantum correlations in terms of coherence, illustrate them through examples, investigate their fundamental properties and implications, and indicate their applications to quantum metrology.

  18. Theory of coherent quantum phase slips in Josephson junction chains with periodic spatial modulations

    Science.gov (United States)

    Svetogorov, Aleksandr E.; Taguchi, Masahiko; Tokura, Yasuhiro; Basko, Denis M.; Hekking, Frank W. J.

    2018-03-01

    We study coherent quantum phase slips which lift the ground state degeneracy in a Josephson junction ring, pierced by a magnetic flux of the magnitude equal to half of a flux quantum. The quantum phase-slip amplitude is sensitive to the normal mode structure of superconducting phase oscillations in the ring (Mooij-Schön modes). These, in turn, are affected by spatial inhomogeneities in the ring. We analyze the case of weak periodic modulations of the system parameters and calculate the corresponding modification of the quantum phase-slip amplitude.

  19. Measurement of coherent $\\pi^{+}$ production in low energy neutrino-Carbon scattering

    CERN Document Server

    Abe, K.

    2016-11-04

    We report the first measurement of the flux-averaged cross section for charged current coherent $\\pi^{+}$ production on carbon for neutrino energies less than 1.5 GeV to a restricted final state phase space region in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso {\\it et al.}, the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. This results contradicts the null results reported by K2K and SciBooNE in a similar neutrino energy region.

  20. Australian methane fluxes

    International Nuclear Information System (INIS)

    Williams, D.J.

    1990-01-01

    Estimates are provided for the amount of methane emitted annually into the atmosphere in Australia for a variety of sources. The sources considered are coal mining, landfill, motor vehicles, natural gas suply system, rice paddies, bushfires, termites, wetland and animals. This assessment indicates that the major sources of methane are natural or agricultural in nature and therefore offer little scope for reduction. Nevertheless the remainder are not trival and reduction of these fluxes could play a significant part in any Australian action on the greenhouse problem. 19 refs., 7 tabs., 1 fig

  1. Statistical intensity variation analysis for rapid volumetric imaging of capillary network flux.

    Science.gov (United States)

    Lee, Jonghwan; Jiang, James Y; Wu, Weicheng; Lesage, Frederic; Boas, David A

    2014-04-01

    We present a novel optical coherence tomography (OCT)-based technique for rapid volumetric imaging of red blood cell (RBC) flux in capillary networks. Previously we reported that OCT can capture individual RBC passage within a capillary, where the OCT intensity signal at a voxel fluctuates when an RBC passes the voxel. Based on this finding, we defined a metric of statistical intensity variation (SIV) and validated that the mean SIV is proportional to the RBC flux [RBC/s] through simulations and measurements. From rapidly scanned volume data, we used Hessian matrix analysis to vectorize a segment path of each capillary and estimate its flux from the mean of the SIVs gathered along the path. Repeating this process led to a 3D flux map of the capillary network. The present technique enabled us to trace the RBC flux changes over hundreds of capillaries with a temporal resolution of ~1 s during functional activation.

  2. Coherent structures and dynamical systems

    Science.gov (United States)

    Jimenez, Javier

    1987-01-01

    Any flow of a viscous fluid has a finite number of degrees of freedom, and can therefore be seen as a dynamical system. A coherent structure can be thought of as a lower dimensional manifold in whose neighborhood the dynamical system spends a substantial fraction of its time. If such a manifold exists, and if its dimensionality is substantially lower that that of the full flow, it is conceivable that the flow could be described in terms of the reduced set of degrees of freedom, and that such a description would be simpler than one in which the existence of structure was not recognized. Several examples are briefly summarized.

  3. Coherent defects in superconducting circuits

    International Nuclear Information System (INIS)

    Mueller, Clemens

    2011-01-01

    The interaction of superconducting circuits with additional quantum systems is a topic that has found extensive study in the recent past. In the limit where the added system are incoherent, this is the standard field of decoherence and the system dynamics can be described by a simple master equation. In the other limit however, when the additional parts are coherent, the resulting time-evolution can become more complicated. In this thesis we have investigated the interaction of superconducting circuits with coherent and incoherent two-level defects. We have shown theoretical calculations characterizing this interaction for all relevant parameter regimes. In the weak coupling limit, the interaction can be described in an effective bath picture, where the TLS act as parts of a large, decohering environment. For strong coupling, however, the coherent dynamics of the full coupled system has to be considered. We show the calculations of the coupled time-evolution and again characterize the interaction by an effective decoherence rate. We also used experimental data to characterize the microscopic origin of the defects and the details of their interaction with the circuits. The results obtained by analyzing spectroscopic data allow us to place strong constraint on several microscopic models for the observed TLS. However, these calculations are not yet fully conclusive as to the physical nature of the TLS. We propose additional experiments to fully characterize the interaction part of the Hamiltonian, thus providing the answer to the question of the physical origin of the coupling. Additionally we have developed a method to directly drive individual defect states via virtual excitation of the qubit. This method allows one to directly probe the properties of single TLS and possibly make use of their superior coherence times for quantum information purposes. The last part of this thesis provided a way for a possible implementation of geometric quantum computation in

  4. Layered Ultrathin Coherent Structures (LUCS)

    International Nuclear Information System (INIS)

    Schuller, I.K.; Falco, C.M.

    1979-01-01

    A new class of superconducting materials, Layered Ultrathin Coherent Structures (LUCS) are described. These materials are produced by sequentially depositing ultrathin layers of materials using high rate magnetron sputtering or thermal evaporation. Strong evidence is presented that layers as thin as 10 A can be prepared in this fashion. Resistivity data indicates that the mean free path is layer thickness limited. A strong disagreement is found between the experimentally measured transition temperatures T/sub c/ and the T/sub c/'s calculated using the Cooper limit approximation. This is interpreted as a change in the band structure or the phonon structure of the material due to layering or to surfaces

  5. Coherent beam-beam effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1992-01-01

    There are two physical pictures that describe the beam-beam interaction in a storage ring collider: The weak-strong and the strong-strong pictures. Both pictures play a role in determining the beam-beam behavior. This review addresses only the strong-strong picture. The corresponding beam dynamical effects are referred to as the coherent beam-beam effects. Some basic knowledge of the weak-strong picture is assumed. To be specific, two beams of opposite charges are considered. (orig.)

  6. Coherence effects in radiative scattering

    International Nuclear Information System (INIS)

    Knoll, J.; Lenk, R.

    1993-03-01

    The bremsstrahl-production of photons in dense matter is reinvestigated using the example of an exactly solvable quantum mechanical model in one space dimension. Coherence phenomena between successive radiative scatterings among the constituents lead to a modification of the production cross section in the medium relative to the incoherent quasi-free prescription used in kinetic models. Analytic expressions for the correction factor have been derived comparing the quantum rates with the corresponding incoherent quasi-free rates. The result has implications for the kinetic description of all kinds of radiative processes in nucleus-nucleus collisions, both on the level of hadron and parton dynamics. (orig.)

  7. Coherently Enhanced Wireless Power Transfer

    OpenAIRE

    Krasnok, Alex; Baranov, Denis G.; Generalov, Andrey; Li, Sergey; Alu, Andrea

    2017-01-01

    Extraction of electromagnetic energy by an antenna from impinging external radiation is at the basis of wireless communications and power transfer (WPT). The maximum of transferred energy is ensured when the antenna is conjugately matched, i.e., when it is resonant and it has an equal coupling with free space and its load, which is not easily implemented in near-field WPT. Here, we introduce the concept of coherently enhanced wireless power transfer. We show that a principle similar to the on...

  8. Experimental coherent control of lasers

    International Nuclear Information System (INIS)

    Gordon, R.; Ramsay, A.J.; Cleaver, J.R.A.; Heberle, A.P.

    2002-01-01

    We experimentally demonstrate coherent control of a laser. A resonant 100-fs optical pulse is injected into a vertical cavity surface emitting laser to introduce a field component with well-defined phase and thereby excite beating oscillations between the transverse lasing modes. By changing the relative phase between two injected pulses, we can enhance or destroy the beating oscillations and select which lasing modes are excited. We discuss resonant pulse injection into lasers and show how mode competition improves controllability by suppressing the phase-sensitive effects of the carriers

  9. Coherent amplification and pulsar phenomena

    International Nuclear Information System (INIS)

    Casperson, L.W.

    1977-01-01

    A modification of the rotating-star model has been developed to interpret the periodic energy bursts from pulsars. This new configuration involves theta-directed oscillation modes in the stellar atmosphere or magnetosphere, and most aspects of the typical pulse characteristics are well accounted for. Gain is provided by resonant interactions with particles trapped in the stellar magnetic field. The most significant feature is the fact that highly directional beaming of the output energy results as a natural consequence of coherence between the radiation fields emerging from various locations about the pulsar; and a localized radiation origin is not required. (Auth.)

  10. Coherent control of plasma dynamics

    Science.gov (United States)

    He, Zhaohan

    2014-10-01

    The concept of coherent control - precise measurement or determination of a process through control of the phase of an applied oscillating field - has been applied to numerous systems with great success. Here, we demonstrate the use of coherent control on plasma dynamics in a laser wakefield electron acceleration experiment. A tightly focused femtosecond laser pulse (10 mJ, 35 fs) was used to generate electron beams by plasma wakefield acceleration in the density down ramp. The technique is based on optimization of the electron beam using a deformable mirror adaptive optical system with an iterative evolutionary genetic algorithm. The image of the electrons on a scintillator screen was processed and used in a fitness function as direct feedback for the optimization algorithm. This coherent manipulation of the laser wavefront leads to orders of magnitude improvement to the electron beam properties such as the peak charge and beam divergence. The laser beam optimized to generate the best electron beam was not the one with the ``best'' focal spot. When a particular wavefront of laser light interacts with plasma, it can affect the plasma wave structures and trapping conditions of the electrons in a complex way. For example, Raman forward scattering, envelope self-modulation, relativistic self-focusing, and relativistic self-phase modulation and many other nonlinear interactions modify both the pulse envelope and phase as the pulse propagates, in a way that cannot be easily predicted and that subsequently dictates the formation of plasma waves. The optimal wavefront could be successfully determined via the heuristic search under laser-plasma conditions that were not known a priori. Control and shaping of the electron energy distribution was found to be less effective, but was still possible. Particle-in-cell simulations were performed to show that the mode structure of the laser beam can affect the plasma wave structure and trapping conditions of electrons, which

  11. Multidimensional coherent spectroscopy made easy

    Energy Technology Data Exchange (ETDEWEB)

    Gundogdu, Kenan; Stone, Katherine W.; Turner, Daniel B. [Department of Chemistry, Massachusetts Institute of Technology, 77 Mass Ave. 6-026 Cambridge, MA 02139 (United States); Nelson, Keith A. [Department of Chemistry, Massachusetts Institute of Technology, 77 Mass Ave. 6-026 Cambridge, MA 02139 (United States)], E-mail: kanelson@mit.edu

    2007-11-15

    We have demonstrated a highly efficient fully coherent 2D spectrometer based on 2D pulse shaping and Fourier beam shaping. The versatility of the design allows one to measure different 2D spectral surfaces consecutively. Easy alignment, inherent phase stability, rotating wave frame detection, and arbitrary waveform generation in all of the beams are important features of this design. We have demonstrated the functionality of the 2D spectrometer by measuring a 2D spectral surface of a GaAs quantum well.

  12. Multidimensional coherent spectroscopy made easy

    International Nuclear Information System (INIS)

    Gundogdu, Kenan; Stone, Katherine W.; Turner, Daniel B.; Nelson, Keith A.

    2007-01-01

    We have demonstrated a highly efficient fully coherent 2D spectrometer based on 2D pulse shaping and Fourier beam shaping. The versatility of the design allows one to measure different 2D spectral surfaces consecutively. Easy alignment, inherent phase stability, rotating wave frame detection, and arbitrary waveform generation in all of the beams are important features of this design. We have demonstrated the functionality of the 2D spectrometer by measuring a 2D spectral surface of a GaAs quantum well

  13. Coherent states in quaternionic quantum mechanics

    Science.gov (United States)

    Adler, Stephen L.; Millard, Andrew C.

    1997-05-01

    We develop Perelomov's coherent states formalism to include the case of a quaternionic Hilbert space. We find that, because of the closure requirement, an attempted quaternionic generalization of the special nilpotent or Weyl group reduces to the normal complex case. For the case of the compact group SU(2), however, coherent states can be formulated using the quaternionic half-integer spin matrices of Finkelstein, Jauch, and Speiser, giving a nontrivial quaternionic analog of coherent states.

  14. Anatomy of a digital coherent receiver

    DEFF Research Database (Denmark)

    Borkowski, Robert; Zibar, Darko; Tafur Monroy, Idelfonso

    2014-01-01

    , orthonormaliation, chromatic dispersion compensation/nonlinear compensation, resampling a nd timing recovery, polarization demultiplexing and equalization, frequency and phase recovery, digital demodulation. We also describe novel subsystems of a digital coherent receiver: modulation format recognition......Digital coherent receivers have gained significant attention in the last decade. The reason for this is that coherent detection, along with digital signal processing (DSP) allows for substantial increase of the channel capacity by employing advanced detection techniques. In this paper, we first...

  15. Laser diode technology for coherent communications

    Science.gov (United States)

    Channin, D. J.; Palfrey, S. L.; Toda, M.

    1989-01-01

    The effect of diode laser characteristics on the overall performance capabilities of coherent communication systems is discussed. In particular, attention is given to optical performance issues for diode lasers in coherent systems, measurements of key performance parameters, and optical requirements for coherent single-channel and multichannel communication systems. The discussion also covers limitations imposed by diode laser optical performance on multichannel system capabilities and implications for future developments.

  16. MESI Cache Coherence Simulator for Teaching Purposes

    OpenAIRE

    Gómez Luna, Juan; Herruzo Gómez, Ezequiel; Benavides Benítez, José Ignacio

    2009-01-01

    Nowadays, the computational systems (multi and uniprocessors) need to avoid the cache coherence problem. There are some techniques to solve this problem. The MESI cache coherence protocol is one of them. This paper presents a simulator of the MESI protocol which is used for teaching the cache memory coherence on the computer systems with hierarchical memory system and for explaining the process of the cache memory location in multilevel cache memory systems. The paper shows a d...

  17. Critical heat flux evaluation

    International Nuclear Information System (INIS)

    Banner, D.

    1995-01-01

    Critical heat flux (CHF) is of importance for nuclear safety and represents the major limiting factors for reactor cores. Critical heat flux is caused by a sharp reduction in the heat transfer coefficient located at the outer surface of fuel rods. Safety requires that this phenomenon also called the boiling crisis should be precluded under nominal or incidental conditions (Class I and II events). CHF evaluation in reactor cores is basically a two-step approach. Fuel assemblies are first tested in experimental loops in order to determine CHF limits under various flow conditions. Then, core thermal-hydraulic calculations are performed for safety evaluation. The paper will go into more details about the boiling crisis in order to pinpoint complexity and lack of fundamental understanding in many areas. Experimental test sections needed to collect data over wide thermal-hydraulic and geometric ranges are described CHF safety margin evaluation in reactors cores is discussed by presenting how uncertainties are mentioned. From basic considerations to current concerns, the following topics are discussed; knowledge of the boiling crisis, CHF predictors, and advances thermal-hydraulic codes. (authors). 15 refs., 4 figs

  18. Neutron flux monitor

    International Nuclear Information System (INIS)

    Seki, Eiji; Tai, Ichiro.

    1984-01-01

    Purpose: To maintain the measuring accuracy and the reponse time within an allowable range in accordance with the change of neutron fluxes in a nuclear reactor pressure vessel. Constitution: Neutron fluxes within a nuclear reactor pressure vessel are detected by detectors, converted into pulse signals and amplified in a range switching amplifier. The amplified signals are further converted through an A/D converter and digital signals from the converter are subjected to a square operation in an square operation circuit. The output from the circuit is inputted into an integration circuit to selectively accumulate the constant of 1/2n, 1 - 1/2n (n is a positive integer) respectively for two continuing signals to perform weighing. Then, the addition is carried out to calculate the integrated value and the addition number is changed by the chane in the number n to vary the integrating time. The integrated value is inputted into a control circuit to control the value of n so that the fluctuation and the calculation time for the integrated value are within a predetermined range and, at the same time, the gain of the range switching amplifier is controlled. (Seki, T.)

  19. Quantum oscillators in the canonical coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, R. de Lima [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Lima, A.F. de; Ferreira, K. de Araujo [Paraiba Univ., Campina Grande, PB (Brazil). Dept. de Fisica; Vaidya, A.N. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica

    2001-11-01

    The main characteristics of the quantum oscillator coherent states including the two-particle Calogero interaction are investigated. We show that these Calogero coherent states are the eigenstates of the second-order differential annihilation operator which is deduced via Wigner-Heisenberg algebraic technique and correspond exactly to the pure uncharged-bosonic states. They posses the important properties of non-orthogonality and completeness. The minimum uncertainty relation for the Wigner oscillator coherent states are investigated. New sets of even and odd coherent states are point out. (author)

  20. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping

    2016-05-18

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  1. Asymmetry and coherence weight of quantum states

    Science.gov (United States)

    Bu, Kaifeng; Anand, Namit; Singh, Uttam

    2018-03-01

    The asymmetry of quantum states is an important resource in quantum information processing tasks such as quantum metrology and quantum communication. In this paper, we introduce the notion of asymmetry weight—an operationally motivated asymmetry quantifier in the resource theory of asymmetry. We study the convexity and monotonicity properties of asymmetry weight and focus on its interplay with the corresponding semidefinite programming (SDP) forms along with its connection to other asymmetry measures. Since the SDP form of asymmetry weight is closely related to asymmetry witnesses, we find that the asymmetry weight can be regarded as a (state-dependent) asymmetry witness. Moreover, some specific entanglement witnesses can be viewed as a special case of an asymmetry witness—which indicates a potential connection between asymmetry and entanglement. We also provide an operationally meaningful coherence measure, which we term coherence weight, and investigate its relationship to other coherence measures like the robustness of coherence and the l1 norm of coherence. In particular, we show that for Werner states in any dimension d all three coherence quantifiers, namely, the coherence weight, the robustness of coherence, and the l1 norm of coherence, are equal and are given by a single letter formula.

  2. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping; Wu, Ying; Lai, Yun

    2016-01-01

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  3. Flux sensitivity of a piecewise normal and superconducting metal loop

    International Nuclear Information System (INIS)

    Buettiker, M.; Klapwijk, T.M.

    1986-01-01

    We consider a loop composed of a superconducting segment and a normal segment with an Aharonov-Bohm flux through the hole of the loop. The normal segment is assumed to be long compared to the superconducting coherence length xi but short compared to a mean inelastic diffusion length. The elementary excitation spectrum of the ground state of this loop is periodic with period hc/2e as long as the superconducting segment is larger than xi. If the superconducting segment length becomes of the order of xi, quasiparticles can tunnel through the superconducting gap and give rise to an excitation spectrum which is periodic with period hc/e. .AE

  4. Coherence in Magnetic Quantum Tunneling

    Science.gov (United States)

    Fernandez, Julio F.

    2001-03-01

    Crystals of single molecule magnets such as Mn_12 and Fe8 behave at low temperatures as a collection of independent spins. Magnetic anisotropy barriers slow down spin-flip processes. Their rate Γ becomes temperature independent at sufficiently low temperature. Quantum tunneling (QT) accounts for this behavior. Currently, spin QT in Mn_12 and Fe8 is assumed to proceed as an incoherent sum of small probability increments that occur whenever a bias field h(t) (arising from hyperfine interactions with nuclear spins) that varies with time t becomes sufficiently small, as in Landau-Zener transitions. Within a two-state model, we study the behavior of a suitably defined coherence time τ_φ and compare it with the correlation time τh for h(t). It turns out that τ_φ >τ_h, when τ_hδ h < hbar, where δ h is the rms deviation of h. We show what effect such coherence has on Γ. Its dependence on a static longitudinal applied field Hz is drastically affected. There is however no effect if the field is swept through resonance.

  5. Enhanced delegated computing using coherence

    Science.gov (United States)

    Barz, Stefanie; Dunjko, Vedran; Schlederer, Florian; Moore, Merritt; Kashefi, Elham; Walmsley, Ian A.

    2016-03-01

    A longstanding question is whether it is possible to delegate computational tasks securely—such that neither the computation nor the data is revealed to the server. Recently, both a classical and a quantum solution to this problem were found [C. Gentry, in Proceedings of the 41st Annual ACM Symposium on the Theory of Computing (Association for Computing Machinery, New York, 2009), pp. 167-178; A. Broadbent, J. Fitzsimons, and E. Kashefi, in Proceedings of the 50th Annual Symposium on Foundations of Computer Science (IEEE Computer Society, Los Alamitos, CA, 2009), pp. 517-526]. Here, we study the first step towards the interplay between classical and quantum approaches and show how coherence can be used as a tool for secure delegated classical computation. We show that a client with limited computational capacity—restricted to an XOR gate—can perform universal classical computation by manipulating information carriers that may occupy superpositions of two states. Using single photonic qubits or coherent light, we experimentally implement secure delegated classical computations between an independent client and a server, which are installed in two different laboratories and separated by 50 m . The server has access to the light sources and measurement devices, whereas the client may use only a restricted set of passive optical devices to manipulate the information-carrying light beams. Thus, our work highlights how minimal quantum and classical resources can be combined and exploited for classical computing.

  6. Coherently Enhanced Wireless Power Transfer

    Science.gov (United States)

    Krasnok, Alex; Baranov, Denis G.; Generalov, Andrey; Li, Sergey; Alù, Andrea

    2018-04-01

    Extraction of electromagnetic energy by an antenna from impinging external radiation is at the basis of wireless communications and wireless power transfer (WPT). The maximum of transferred energy is ensured when the antenna is conjugately matched, i.e., when it is resonant and it has an equal coupling with free space and its load. This condition, however, can be easily affected by changes in the environment, preventing optimal operation of a WPT system. Here, we introduce the concept of coherently enhanced WPT that allows us to bypass this difficulty and achieve dynamic control of power transfer. The approach relies on coherent excitation of the waveguide connected to the antenna load with a backward propagating signal of specific amplitude and phase. This signal creates a suitable interference pattern at the load resulting in a modification of the local wave impedance, which in turn enables conjugate matching and a largely increased amount of extracted energy. We develop a simple theoretical model describing this concept, demonstrate it with full-wave numerical simulations for the canonical example of a dipole antenna, and verify experimentally in both near-field and far-field regimes.

  7. Coherent states: a contemporary panorama Coherent states: a contemporary panorama

    Science.gov (United States)

    Twareque Ali, S.; Antoine, Jean-Pierre; Bagarello, Fabio; Gazeau, Jean-Pierre

    2012-06-01

    Coherent states (CS) of the harmonic oscillator (also called canonical CS) were introduced in 1926 by Schrödinger in answer to a remark by Lorentz on the classical interpretation of the wave function. They were rediscovered in the early 1960s, first (somewhat implicitly) by Klauder in the context of a novel representation of quantum states, then by Glauber and Sudarshan for the description of coherence in lasers. Since then, CS have grown into an extremely rich domain that pervades almost every corner of physics and have also led to the development of several flourishing topics in mathematics. Along the way, a number of review articles have appeared in the literature, devoted to CS, notably the 1985 reprint volume of Klauder and Skagerstam [1], the 1990 review paper by Zhang et al [2], the 1993 Oak Ridge Conference [3] and the 1995 review paper by Ali et al [4]. Textbooks also have been published, among which one might mention the ground breaking text of Perelomov [5] focusing on the group-theoretical aspects, that of Ali et al [6]1 analyzing systematically the mathematical structure beyond the group-theoretical approach and also the relation to wavelet analysis, that of Dodonov and Man'ko [7] mostly devoted to quantum optics, that of Gazeau [8] more oriented towards the physical, probabilistic and quantization aspects, and finally the very recent one by Combescure and Robert [9]. In retrospect, one can see that the development of CS has gone through a two-phase transition. First, the (simultaneous) discovery in 1972 by Gilmore and Perelomov that CS were rooted in group theory, then the realization that CS can be defined in a purely algebraic way, as an eigenvalue problem or by a series expansion (Malkin and Man'ko 1969, Barut and Girardello 1971, Gazeau and Klauder 1999; references to the original articles may be found in the textbooks quoted above). Both facts resulted in an explosive expansion of the CS literature. We thought, therefore, that the time was ripe

  8. 基于视频叠加的心理暗示%Information producing of psychological suggestion based on video superimposing

    Institute of Scientific and Technical Information of China (English)

    郭小一; 老松杨; 张国华

    2012-01-01

    针对未来心理战民意制约、隐式作战等趋势,提出了基于视频叠加的心理暗示(PSBVS)的构想.分析了PSBVS媒体基础、理论基础和方法基础,为实现信息有效编码进而有效影响受众心理,围绕暗示信息生成构建了一个基本的理论框架.研究了主体编码过程、暗示信息视频语义层次结构、受众心理效应过程以及三者之间的关联,针对感知特征层建立了视频叠加的认知参数模型,对参数设置进行了初步分析,提出了视频叠加暗示信息的心理效果模型,力图为信息内容和形式的确定提供一定的依据和支持.除了心理战,PSBVS在广告营销、医疗和教育等领域都具有重要的应用价值.%An idea of psychological suggestion based on video superimposing (PSBVS) was proposed for the trend of public-opinion restriction and covert operation in future psywar. The media basis, theory basis and method basis of PSBVS were analyzed firstly. Then, in order to encode information effectively and impact the psychology of psywar object successfully, a theory frame was established on suggestive information producing. The information coding process, video hiberarchy, and psychological effectiveness process were researched systemically, together with the relationship among them. The cognitive parameter model of video superimposing was constructed for perceptive-feature-level. An effect evaluation model of suggestive information was proposed, which can provide a guidance and feedback to parameter set. A theoretical support was provided for decision of information content and form. Besides psychology warfare, PSBVS has a significant applying value in fields such as commerce advertising, medicare and education.

  9. Nano structured materials studied by coherent X-ray diffraction

    International Nuclear Information System (INIS)

    Gulden, Johannes

    2013-03-01

    Structure determination with X-rays in crystallography is a rapidly evolving field. Crystallographic methods for structure determination are based on the assumptions about the crystallinity of the sample. It is vital to understand the structure of possible defects in the crystal, because they can influence the structure determination. All conventional methods to characterize defects require a modelling through simulated data. No direct methods exist to image the core of defects in crystals. Here a new method is proposed, which will enable to visualize the individual scatterers around and at defects in crystals. The method is based on coherent X-ray scattering. X-rays are perfectly suited since they can penetrate thick samples and buried structures can be investigated Recent developments increased the coherent flux of X-Ray sources such as synchrotrons by orders of magnitude. As a result, the use of the coherent properties of X-rays is emerging as a new aspect of X-ray science. New upcoming and operating X-ray laser sources will accelerate this trend. One new method which has the capacity to recover structural information from the coherently scattered photons is Coherent X-ray Diffraction Imaging (CXDI). The main focus of this thesis is the investigation of the structure and the dynamics of colloidal crystals. Colloidal crystals can be used as a model for atomic crystals in order to understand the growth and defect structure. Despite the large interest in these structures, many details are still unknown.Therefore, it is vital to develop new approaches to measure the core of defects in colloidal crystals. After an introduction into the basics of the field of coherent X-ray scattering, this thesis introduces a novel method, Small Angle Bragg Coherent Diffractive Imaging, (SAB-CDI). This new measurement technique which besides the relevance to colloidal crystals can be applied to a large variety of nano structured materials. To verify the experimental possibilities the

  10. Nano structured materials studied by coherent X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gulden, Johannes

    2013-03-15

    Structure determination with X-rays in crystallography is a rapidly evolving field. Crystallographic methods for structure determination are based on the assumptions about the crystallinity of the sample. It is vital to understand the structure of possible defects in the crystal, because they can influence the structure determination. All conventional methods to characterize defects require a modelling through simulated data. No direct methods exist to image the core of defects in crystals. Here a new method is proposed, which will enable to visualize the individual scatterers around and at defects in crystals. The method is based on coherent X-ray scattering. X-rays are perfectly suited since they can penetrate thick samples and buried structures can be investigated Recent developments increased the coherent flux of X-Ray sources such as synchrotrons by orders of magnitude. As a result, the use of the coherent properties of X-rays is emerging as a new aspect of X-ray science. New upcoming and operating X-ray laser sources will accelerate this trend. One new method which has the capacity to recover structural information from the coherently scattered photons is Coherent X-ray Diffraction Imaging (CXDI). The main focus of this thesis is the investigation of the structure and the dynamics of colloidal crystals. Colloidal crystals can be used as a model for atomic crystals in order to understand the growth and defect structure. Despite the large interest in these structures, many details are still unknown.Therefore, it is vital to develop new approaches to measure the core of defects in colloidal crystals. After an introduction into the basics of the field of coherent X-ray scattering, this thesis introduces a novel method, Small Angle Bragg Coherent Diffractive Imaging, (SAB-CDI). This new measurement technique which besides the relevance to colloidal crystals can be applied to a large variety of nano structured materials. To verify the experimental possibilities the

  11. Optical Coherence Tomography Angiography Features of Iris Racemose Hemangioma in 4 Cases.

    Science.gov (United States)

    Chien, Jason L; Sioufi, Kareem; Ferenczy, Sandor; Say, Emil Anthony T; Shields, Carol L

    2017-10-01

    Optical coherence tomography angiography (OCTA) allows visualization of iris racemose hemangioma course and its relation to the normal iris microvasculature. To describe OCTA features of iris racemose hemangioma. Descriptive, noncomparative case series at a tertiary referral center (Ocular Oncology Service of Wills Eye Hospital). Patients diagnosed with unilateral iris racemose hemangioma were included in the study. Features of iris racemose hemangioma on OCTA. Four eyes of 4 patients with unilateral iris racemose hemangioma were included in the study. Mean patient age was 50 years, all patients were white, and Snellen visual acuity was 20/20 in each case. All eyes had sectoral iris racemose hemangioma without associated iris or ciliary body solid tumor on clinical examination and ultrasound biomicroscopy. By anterior segment OCT, the racemose hemangioma was partially visualized in all cases. By OCTA, the hemangioma was clearly visualized as a uniform large-caliber vascular tortuous loop with intense flow characteristics superimposed over small-caliber radial iris vessels against a background of low-signal iris stroma. The vascular course on OCTA resembled a light bulb filament (filament sign), arising from the peripheral iris (base of light bulb) and forming a tortuous loop on reaching its peak (midfilament) near the pupil (n = 3) or midzonal iris (n = 1), before returning to the peripheral iris (base of light bulb). Intravenous fluorescein angiography performed in 1 eye depicted the iris hemangioma; however, small-caliber radial iris vessels were more distinct on OCTA than intravenous fluorescein angiography. Optical coherence tomography angiography is a noninvasive vascular imaging modality that clearly depicts the looping course of iris racemose hemangioma. Optical coherence tomography angiography depicted fine details of radial iris vessels, not distinct on intravenous fluorescein angiography.

  12. Manipulating quantum coherence of charge states in interacting double-dot Aharonov–Bohm interferometers

    Science.gov (United States)

    Jin, Jinshuang; Wang, Shikuan; Zhou, Jiahuan; Zhang, Wei-Min; Yan, YiJing

    2018-04-01

    We investigate the dynamics of charge-state coherence in a degenerate double-dot Aharonov–Bohm interferometer with finite inter-dot Coulomb interactions. The quantum coherence of the charge states is found to be sensitive to the transport setup configurations, involving both the single-electron impurity channels and the Coulomb-assisted ones. We numerically demonstrate the emergence of a complete coherence between the two charge states, with the relative phase being continuously controllable through the magnetic flux. Interestingly, a fully coherent charge qubit arises at the double-dots electron pair tunneling resonance condition, where the chemical potential of one electrode is tuned at the center between a single-electron impurity channel and the related Coulomb-assisted channel. This pure quantum state of charge qubit could be experimentally realized at the current–voltage characteristic turnover position, where differential conductance sign changes. We further elaborate the underlying mechanism for both the real-time and the stationary charge-states coherence in the double-dot systems of study.

  13. Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Munn, W.I.

    1981-01-01

    The Fast Flux Test Facility (FFTF), located on the Hanford site a few miles north of Richland, Washington, is a major link in the chain of development required to sustain and advance Liquid Metal Fast Breeder Reactor (LMFBR) technology in the United States. This 400 MWt sodium cooled reactor is a three loop design, is operated by Westinghouse Hanford Company for the US Department of Energy, and is the largest research reactor of its kind in the world. The purpose of the facility is three-fold: (1) to provide a test bed for components, materials, and breeder reactor fuels which can significantly extend resource reserves; (2) to produce a complete body of base data for the use of liquid sodium in heat transfer systens; and (3) to demonstrate inherent safety characteristics of LMFBR designs

  14. Utility of circulating IGF-I as a biomarker for assessing body composition changes in men during periods of high physical activity superimposed upon energy and sleep restriction.

    Science.gov (United States)

    Nindl, Bradley C; Alemany, Joseph A; Kellogg, Mark D; Rood, Jennifer; Allison, Steven A; Young, Andrew J; Montain, Scott J

    2007-07-01

    Insulin-like growth factor (IGF)-I is a biomarker that may have greater utility than other conventional nutritional biomarkers in assessing nutritional, health, and fitness status. We hypothesized that the IGF-I system would directionally track a short-term energy deficit and would be more related to changes in body composition than other nutritional biomarkers. Thirty-five healthy men (24 +/- 0.3 yr) underwent 8 days of exercise and energy imbalance. Total and free IGF-I, IGF binding proteins-1, -2, and -3, the acid labile subunit, transferrin, ferritin, retinol binding protein, prealbumin, testosterone, triiodothyronine, thyroxine, and leptin responses were measured. Dual-energy X-ray absorptiometry assessed changes in body mass and composition. Repeated-measures ANOVA, correlation analysis, and receiver operator characteristic curves were used for statistical analyses (P losing >5% body mass. The IGF-I system is an important adjunct in the overall assessment of adaptation to stress imposed by high levels of physical activity superimposed on energy and sleep restriction and is more closely associated with losses in body mass and fat-free mass than other conventional nutritional biomarkers.

  15. Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

    Science.gov (United States)

    Takashima, Keisuke; Kaneko, Toshiro

    2017-06-01

    The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

  16. Neuro-fuzzy computing for vibration-based damage localization and severity estimation in an experimental wind turbine blade with superimposed operational effects

    Science.gov (United States)

    Hoell, Simon; Omenzetter, Piotr

    2016-04-01

    Fueled by increasing demand for carbon neutral energy, erections of ever larger wind turbines (WTs), with WT blades (WTBs) with higher flexibilities and lower buckling capacities lead to increasing operation and maintenance costs. This can be counteracted with efficient structural health monitoring (SHM), which allows scheduling maintenance actions according to the structural state and preventing dramatic failures. The present study proposes a novel multi-step approach for vibration-based structural damage localization and severity estimation for application in operating WTs. First, partial autocorrelation coefficients (PACCs) are estimated from vibrational responses. Second, principal component analysis is applied to PACCs from the healthy structure in order to calculate scores. Then, the scores are ranked with respect to their ability to differentiate different damage scenarios. This ranking information is used for constructing hierarchical adaptive neuro-fuzzy inference systems (HANFISs), where cross-validation is used to identify optimal numbers of hierarchy levels. Different HANFISs are created for the purposes of structural damage localization and severity estimation. For demonstrating the applicability of the approach, experimental data are superimposed with signals from numerical simulations to account for characteristics of operational noise. For the physical experiments, a small scale WTB is excited with a domestic fan and damage scenarios are introduced non-destructively by attaching small masses. Numerical simulations are also performed for a representative fully functional small WT operating in turbulent wind. The obtained results are promising for future applications of vibration-based SHM to facilitate improved safety and reliability of WTs at lower costs.

  17. Flux compactifications and generalized geometries

    International Nuclear Information System (INIS)

    Grana, Mariana

    2006-01-01

    Following the lectures given at CERN Winter School 2006, we present a pedagogical overview of flux compactifications and generalized geometries, concentrating on closed string fluxes in type II theories. We start by reviewing the supersymmetric flux configurations with maximally symmetric four-dimensional spaces. We then discuss the no-go theorems (and their evasion) for compactifications with fluxes. We analyse the resulting four-dimensional effective theories for Calabi-Yau and Calabi-Yau orientifold compactifications, concentrating on the flux-induced superpotentials. We discuss the generic mechanism of moduli stabilization and illustrate with two examples: the conifold in IIB and a T 6 /(Z 3 x Z 3 ) torus in IIA. We finish by studying the effective action and flux vacua for generalized geometries in the context of generalized complex geometry

  18. Flux compactifications and generalized geometries

    Energy Technology Data Exchange (ETDEWEB)

    Grana, Mariana [Service de Physique Theorique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex (France)

    2006-11-07

    Following the lectures given at CERN Winter School 2006, we present a pedagogical overview of flux compactifications and generalized geometries, concentrating on closed string fluxes in type II theories. We start by reviewing the supersymmetric flux configurations with maximally symmetric four-dimensional spaces. We then discuss the no-go theorems (and their evasion) for compactifications with fluxes. We analyse the resulting four-dimensional effective theories for Calabi-Yau and Calabi-Yau orientifold compactifications, concentrating on the flux-induced superpotentials. We discuss the generic mechanism of moduli stabilization and illustrate with two examples: the conifold in IIB and a T{sup 6} /(Z{sub 3} x Z{sub 3}) torus in IIA. We finish by studying the effective action and flux vacua for generalized geometries in the context of generalized complex geometry.

  19. Lunar periodicity in the shell flux of planktonic foraminifera in the Gulf of Mexico

    Science.gov (United States)

    Jonkers, Lukas; Reynolds, Caitlin E.; Richey, Julie N.; Hall, Ian R.

    2015-01-01

    Synchronised reproduction offers clear benefits to planktonic foraminifera – an important group of marine calcifiers – as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 4-year time series (mostly at weekly resolution) from the northern Gulf of Mexico, we show that the shell flux ofGloborotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer, Globigerinoides ruber (both pink and white varieties), Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida and Globigerinita glutinata is characterised by lunar periodicity. However, the lunar rhythm is not present in all size fractions of each species and tends to be more dominant in the flux of larger shells, consistent with reproduction being more prevalent in larger specimens. Lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. In most species peak fluxes occur predominantly around, or just after, full moon. Only G. siphonifera and G. calida show a contrasting pattern with peaks concentrated around new moon. Although the exact cause of the synchronisation remains elusive, our data considerably increase the number of species for which lunar synchronised reproduction is reported and suggest that such reproductive behaviour is common in many species of planktonic foraminifera.

  20. Persistence of radon-222 flux during monsoon at a geothermal zone in Nepal

    International Nuclear Information System (INIS)

    Girault, Frederic; Koirala, Bharat Prasad; Perrier, Frederic; Richon, Patrick; Rajaure, Sudhir

    2009-01-01

    The Syabru-Bensi hydrothermal zone, Langtang region (Nepal), is characterized by high radon-222 and CO 2 discharge. Seasonal variations of gas fluxes were studied on a reference transect in a newly discovered gas discharge zone. Radon-222 and CO 2 fluxes were measured with the accumulation chamber technique, coupled with the scintillation flask method for radon. In the reference transect, fluxes reach exceptional mean values, as high as 8700 ± 1500 g m -2 d -1 for CO 2 and 3400 ± 100 x 10 -3 Bq m -2 s -1 for radon. Gases fluxes were measured in September 2007 during the monsoon and during the dry winter season, in December 2007 to January 2008 and in December 2008 to January 2009. Contrary to expectations, radon and its carrier gas fluxes were similar during both seasons. The integrated flux along this transect was approximately the same for radon, with a small increase of 11 ± 4% during the wet season, whereas it was reduced by 38 ± 5% during the monsoon for CO 2 . In order to account for the persistence of the high gas emissions during monsoon, watering experiments have been performed at selected radon measurement points. After watering, radon flux decreased within 5 min by a factor of 2-7 depending on the point. Subsequently, it returned to its original value, firstly, by an initial partial recovery within 3-4 h, followed by a slow relaxation, lasting around 10 h and possibly superimposed by diurnal variations. Monsoon, in this part of the Himalayas, proceeds generally by brutal rainfall events separated by two- or three-day lapses. Thus, the recovery ability shown in the watering experiments accounts for the observed long-term persistence of gas discharge. This persistence is an important asset for long-term monitoring, for example to study possible temporal variations associated with stress accumulation and release.

  1. Effects of quantum coherence on work statistics

    Science.gov (United States)

    Xu, Bao-Ming; Zou, Jian; Guo, Li-Sha; Kong, Xiang-Mu

    2018-05-01

    In the conventional two-point measurement scheme of quantum thermodynamics, quantum coherence is destroyed by the first measurement. But as we know the coherence really plays an important role in the quantum thermodynamics process, and how to describe the work statistics for a quantum coherent process is still an open question. In this paper, we use the full counting statistics method to investigate the effects of quantum coherence on work statistics. First, we give a general discussion and show that for a quantum coherent process, work statistics is very different from that of the two-point measurement scheme, specifically the average work is increased or decreased and the work fluctuation can be decreased by quantum coherence, which strongly depends on the relative phase, the energy level structure, and the external protocol. Then, we concretely consider a quenched one-dimensional transverse Ising model and show that quantum coherence has a more significant influence on work statistics in the ferromagnetism regime compared with that in the paramagnetism regime, so that due to the presence of quantum coherence the work statistics can exhibit the critical phenomenon even at high temperature.

  2. Information cloning of harmonic oscillator coherent states

    Indian Academy of Sciences (India)

    We show that in the case of unknown harmonic oscillator coherent statesit is possible to achieve what we call perfect information cloning. By this we mean that it is still possible to make arbitrary number of copies of a state which has exactly the same information content as the original unknown coherent state. By making use ...

  3. Coherent acceptability measures in multiperiod models

    NARCIS (Netherlands)

    Roorda, Berend; Schumacher, Hans; Engwerda, Jacob

    2005-01-01

    The framework of coherent risk measures has been introduced by Artzner et al. (1999; Math. Finance 9, 203–228) in a single-period setting. Here, we investigate a similar framework in a multiperiod context. We add an axiom of dynamic consistency to the standard coherence axioms, and obtain a

  4. Quantum Processes Which Do Not Use Coherence

    Directory of Open Access Journals (Sweden)

    Benjamin Yadin

    2016-11-01

    Full Text Available A major signature of quantum mechanics beyond classical physics is coherence, the existence of superposition states. The recently developed resource theory of quantum coherence allows the formalization of incoherent operations—those operations which cannot create coherence. We identify the set of operations which additionally do not use coherence. These are such that coherence cannot be exploited by a classical observer, who measures incoherent properties of the system, to go beyond classical dynamics. We give a physical interpretation in terms of interferometry and prove a dilation theorem, showing how these operations can always be constructed by the system interacting, in an incoherent way, with an ancilla. Such a physical justification is not known for the incoherent operations; thus, our results lead to a physically well-motivated resource theory of coherence. Next, we investigate the implications for coherence in multipartite systems. We show that quantum correlations can be defined naturally with respect to a fixed basis, providing a link between coherence and quantum discord. We demonstrate the interplay between these two quantities in the operations that we study and suggest implications for the theory of quantum discord by relating these operations to those which cannot create discord.

  5. Imaging granulomatous lesions with optical coherence tomography

    DEFF Research Database (Denmark)

    Banzhaf, Christina; Jemec, Gregor B E

    2012-01-01

    To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors.......To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors....

  6. Extracting subsurface fingerprints using optical coherence tomography

    CSIR Research Space (South Africa)

    Akhoury, SS

    2015-02-01

    Full Text Available Subsurface Fingerprints using Optical Coherence Tomography Sharat Saurabh Akhoury, Luke Nicholas Darlow Modelling and Digital Science, Council for Scientific and Industrial Research, Pretoria, South Africa Abstract Physiologists have found... approach to extract the subsurface fingerprint representation using a high-resolution imaging technology known as Optical Coherence Tomography (OCT). ...

  7. Complete destructive interference of partially coherent fields

    NARCIS (Netherlands)

    Gbur, G.J.; Visser, T.D.; Wolf, E.

    2004-01-01

    A three-point source model is used to study the interference of wavefields which are mutually partially coherent. It is shown that complete destructive interference of the fields is possible in such a "three-pinhole interferometer" even if the sources are not fully coherent with respect to each

  8. Martingale characterizations of coherent acceptability measures

    NARCIS (Netherlands)

    Roorda, Berend

    2002-01-01

    The coherent risk framework is linked to martingale valuation by adding hedgeinvariance as a fifth axiom, motivated by the concept of consistent hedging. The resulting subclass, called coherent pre-hedge (CoPr) measures, is characterized by a martingale condition on the test set that underlies a

  9. Heat Flux Instrumentation Laboratory (HFIL)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Heat Flux Instrumentation Laboratory is used to develop advanced, flexible, thin film gauge instrumentation for the Air Force Research Laboratory....

  10. Optical coherence tomography in dermatology

    Science.gov (United States)

    Sattler, Elke; Kästle, Raphaela; Welzel, Julia

    2013-06-01

    Optical coherence tomography (OCT) is a noninvasive diagnostic method that offers a view into the superficial layers of the skin in vivo in real-time. An infrared broadband light source allows the investigation of skin architecture and changes up to a depth of 1 to 2 mm with a resolution between 15 and 3 μm, depending on the system used. Thus OCT enables evaluation of skin lesions, especially nonmelanoma skin cancers and inflammatory diseases, quantification of skin changes, visualization of parasitic infestations, and examination of other indications such as the investigation of nails. OCT provides a quick and useful diagnostic imaging technique for a number of clinical questions and is a valuable addition or complement to other noninvasive imaging tools such as dermoscopy, high-frequency ultrasound, and confocal laser scan microscopy.

  11. Coherent Radiation in Atomic Systems

    Science.gov (United States)

    Sutherland, Robert Tyler

    Over the last century, quantum mechanics has dramatically altered our understanding of light and matter. Impressively, exploring the relationship between the two continues to provide important insights into the physics of many-body systems. In this thesis, we add to this still growing field of study. Specifically, we discuss superradiant line-broadening and cooperative dipole-dipole interactions for cold atom clouds in the linear-optics regime. We then discuss how coherent radiation changes both the photon scattering properties and the excitation distribution of atomic arrays. After that, we explore the nature of superradiance in initially inverted clouds of multi-level atoms. Finally, we explore the physics of clouds with degenerate Zeeman ground states, and show that this creates quantum effects that fundamentally change the photon scattering of atomic ensembles.

  12. Geometry of generalized coherent states

    International Nuclear Information System (INIS)

    Bacry, H.; Centre National de la Recherche Scientifique, 13 - Marseille; Grossmann, A.; Zak, J.

    1975-09-01

    Various attempts have been made to generalize the concept of coherent states (c.s.). One of them, due to Perelomov, seems to be very promising but no restrictive enough. The Perelomov c.s. are briefly reviewed. One shows how his definition gives rise to Radcliffe's c.s. Relationship between the usual and Radcliffe's c.s. can be investigated either from group contraction point of view (Arecchi et al.) or from a physical point of view (with the aid of the Poincare sphere of elliptic polarizations of electromagnetic plane waves). The question of finding complete subsets of c.s. is revisited and an attempt is made to restrict the Perelomov definition [fr

  13. Nuclear structure with coherent states

    CERN Document Server

    Raduta, Apolodor Aristotel

    2015-01-01

    This book covers the essential features of a large variety of nuclear structure properties, both collective and microscopic in nature. Most of results are given in an analytical form thus giving deep insight into the relevant phenomena. Using coherent states as variational states, which allows a description in the classical phase space, or provides the generating function for a boson basis, is an efficient tool to account, in a realistic fashion, for many complex properties. A detailed comparison with all existing nuclear structure models provides readers with a proper framework and, at the same time, demonstrates the prospects for new developments. The topics addressed are very much of current concern in the field. The book will appeal to practicing researchers and, due to its self-contained account, can also be successfully read and used by new graduate students.

  14. QCD jets from coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Curci, G [European Organization for Nuclear Research, Geneva (Switzerland); Greco, M; Srivastava, Y [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati

    1979-11-19

    A recently proposed approach to the problem of infrared and mass singularities in QCD based on the formalism of coherent states, is extended to discuss massless quark and gluon jets. The present results include all leading (ln delta) terms as well as finite terms in the energy loss epsilon, in addition to the usual ln epsilon associated with ln delta. The formulae agree with explicit perturbative calculations, whenever available. Explicit expressions for the total Ksub(T) distributions are given which take into account transverse-momentum conservation. Predictions are also made for the Q/sup 2/ dependence of the mean Ksub(T)/sup 2/ for quark and gluon jets. The jet ksub(T) distributions are extrapolated for low ksub(T) and shown to describe with good accuracy the data for eanti e..-->..qanti q..-->.. hadrons. Numerical predictions are also presented for the forthcoming PETRA, PEP and LEP machines.

  15. Coherence properties of holes subject to a fluctuating spin chirality

    International Nuclear Information System (INIS)

    Wheatley, J.M.; Hong, T.M.

    1991-01-01

    The coherence properties of holes coupled to short-ranged chiral spin fluctuations with a characteristic chiral spin fluctuation time τ ch =ω ch -1 are investigated in two dimensions. At temperatures kT much-lt 4π 2 left-angle φ 2 right-angle -1 ℎω ch hole quasiparticles exist and propagate with a renormalized mass m * /m=1+left-angle φ 2 right-angle ℎ/16πma 0 2 ω ch . $langle phi sup 2 rangle--- is the amplitude of the local fictitious flux fluctuation and a 0 is a lattice cutoff. At temperatures kT much-gt 4π 2 left-angle φ 2 right-angle -1 ℎω ch an effective-mass approximation is invalid and we find that the hole diffuses according to a logarithmic diffusion law in the quasistatic chiral field. The unusual diffusion law is a consequence of the long-ranged nature of the gauge field. The result shows that the holes do not form a coherent quantum fluid in the quasistatic regime

  16. CIRCE: A dedicated storage ring for coherent THz synchrotron radiation

    International Nuclear Information System (INIS)

    Byrd, J.M.; Martin, Michael C.; McKinney, W.R.; Munson, D.V.; Nishimura, H.; Robin, D.S.; Sannibale, F.; Schlueter, R.D.; Thur, W.G.; Jung, J.Y.; Wan, W.

    2003-01-01

    We present the concepts for an electron storage ring dedicated to and optimized for the production of stable coherent synchrotron radiation (CSR) over the far-infrared terahertz wavelength range from 200 mm to about one cm. CIRCE (Coherent InfraRed CEnter) will be a 66 m circumference ring located on top of the ALS booster synchrotron shielding tunnel and using the existing ALS injector. This location provides enough floor space for both the CIRCE ring, its required shielding, and numerous beamlines. We briefly outline a model for CSR emission in which a static bunch distortion induced by the synchrotron radiation field is used to significantly extend the stable CSR emission towards higher frequencies. This model has been verified with experimental CSR results. We present the calculated CIRCE photon flux where a gain of 6-9 orders of magnitude is shown compared to existing far-IR sources. Additionally, the particular design of the dipole vacuum chamber has been optimized to allow an excellent transmission of these far-infrared wavelengths. We believe that the CIRCE source can be constructed for a modest cost

  17. Coherent Diffractive Imaging at LCLS

    Science.gov (United States)

    Schulz, Joachim

    2010-03-01

    Soft x-ray FEL light sources produce ultrafast x-ray pulses with outstanding high peak brilliance. This might enable the structure determination of proteins that cannot be crystallized. The deposited energy would destroy the molecules completely, but owing to the short pulses the destruction will ideally only happen after the termination of the pulse. In order to address the many challenges that we face in attempting molecular diffraction, we have carried out experiments in coherent diffraction from protein nanocrystals at the Linac Coherent Light Source (LCLS) at SLAC. The periodicity of these objects gives us much higher scattering signals than uncrystallized proteins would. The crystals are filtered to sizes less than 2 micron, and delivered to the pulsed X-ray beam in a liquid jet. The effects of pulse duration and fluence on the high-resolution structure of the crystals have been studied. Diffraction patterns are recorded at a repetition rate of 30 Hz with pnCCD detectors. This allows us to take 108,000 images per hour. With 2-mega-pixel-detectors this gives a data-rate of more than 400 GB per hour. The automated sorting and evaluation of hundreds of thousands images is another challenge of this kind of experiments. Preliminary results will be presented on our first LCLS experiments. This work was carried out as part of a collaboration, for which Henry Chapman is the spokesperson. The collaboration consists of CFEL DESY, Arizona State University, SLAC, Uppsala University, LLNL, The University of Melbourne, LBNL, the Max Planck Institute for Medical Research, and the Max Planck Advanced Study Group (ASG) at the CFEL. The experiments were carried out using the CAMP apparatus, which was designed and built by the Max Planck ASG at CFEL. The LCLS is operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

  18. Coherent State Quantization and Moment Problem

    Directory of Open Access Journals (Sweden)

    J. P. Gazeau

    2010-01-01

    Full Text Available Berezin-Klauder-Toeplitz (“anti-Wick” or “coherent state” quantization of the complex plane, viewed as the phase space of a particle moving on the line, is derived from the resolution of the unity provided by the standard (or gaussian coherent states. The construction of these states and their attractive properties are essentially based on the energy spectrum of the harmonic oscillator, that is on natural numbers. We follow in this work the same path by considering sequences of non-negative numbers and their associated “non-linear” coherent states. We illustrate our approach with the 2-d motion of a charged particle in a uniform magnetic field. By solving the involved Stieltjes moment problem we construct a family of coherent states for this model. We then proceed with the corresponding coherent state quantization and we show that this procedure takes into account the circle topology of the classical motion.

  19. Coherent control of photoelectron wavepacket angular interferograms

    International Nuclear Information System (INIS)

    Hockett, P; Wollenhaupt, M; Baumert, T

    2015-01-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light–matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable. (paper)

  20. Coherent control of photoelectron wavepacket angular interferograms

    Science.gov (United States)

    Hockett, P.; Wollenhaupt, M.; Baumert, T.

    2015-11-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light-matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

  1. Higher coherent x-ray laser

    International Nuclear Information System (INIS)

    Hasegawa, Noboru; Nagashima, Keisuke; Kawachi, Tetsuya

    2001-01-01

    X-ray lasers generated by an ultra short pulse laser have advantages such as monochromatic, short pulse duration, small beam divergence, high intensity, and coherence. Spatial coherence is most important for applications, we have investigated the transient collisional excitation (TCE) scheme x-ray laser lasing from Ne-like titanium (31.6 nm), Ne-like silver (13.9 nm) and tin (11.9 nm). However, the spatial coherence was not so good with this scheme. We have been studying to improve the spatial coherence of the x-ray laser and have proposed to use coherent seed light tuned to the x-ray laser wavelength generated from higher harmonics generation (HHG), which is introduced to the x-ray laser medium (Ne-like titanium, Ni-like silver plasmas). We present about the theoretical study of the coupling efficiency HHG light with x-ray laser medium. (author)

  2. KoFlux: Korean Regional Flux Network in AsiaFlux

    Science.gov (United States)

    Kim, J.

    2002-12-01

    AsiaFlux, the Asian arm of FLUXNET, held the Second International Workshop on Advanced Flux Network and Flux Evaluation in Jeju Island, Korea on 9-11 January 2002. In order to facilitate comprehensive Asia-wide studies of ecosystem fluxes, the meeting launched KoFlux, a new Korean regional network of long-term micrometeorological flux sites. For a successful assessment of carbon exchange between terrestrial ecosystems and the atmosphere, an accurate measurement of surface fluxes of energy and water is one of the prerequisites. During the 7th Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) held in Nagoya, Japan on 1-2 October 2001, the Implementation Committee of the Coordinated Enhanced Observing Period (CEOP) was established. One of the immediate tasks of CEOP was and is to identify the reference sites to monitor energy and water fluxes over the Asian continent. Subsequently, to advance the regional and global network of these reference sites in the context of both FLUXNET and CEOP, the Korean flux community has re-organized the available resources to establish a new regional network, KoFlux. We have built up domestic network sites (equipped with wind profiler and radiosonde measurements) over deciduous and coniferous forests, urban and rural rice paddies and coastal farmland. As an outreach through collaborations with research groups in Japan, China and Thailand, we also proposed international flux sites at ecologically and climatologically important locations such as a prairie on the Tibetan plateau, tropical forest with mixed and rapid land use change in northern Thailand. Several sites in KoFlux already begun to accumulate interesting data and some highlights are presented at the meeting. The sciences generated by flux networks in other continents have proven the worthiness of a global array of micrometeorological flux towers. It is our intent that the launch of KoFlux would encourage other scientists to initiate and

  3. Influence of HeartMath quick coherence technique on ...

    African Journals Online (AJOL)

    ... of high psychophysiological coherence, decreased feelings of sadness and increased feelings of peacefulness. Psychophysiological and emotional state findings are discussed in relation to health and sport psychology, theory and practice. Keywords: Biofeedback, physiological coherence, Quick Coherence Technique, ...

  4. From elementary flux modes to elementary flux vectors: Metabolic pathway analysis with arbitrary linear flux constraints

    Science.gov (United States)

    Klamt, Steffen; Gerstl, Matthias P.; Jungreuthmayer, Christian; Mahadevan, Radhakrishnan; Müller, Stefan

    2017-01-01

    Elementary flux modes (EFMs) emerged as a formal concept to describe metabolic pathways and have become an established tool for constraint-based modeling and metabolic network analysis. EFMs are characteristic (support-minimal) vectors of the flux cone that contains all feasible steady-state flux vectors of a given metabolic network. EFMs account for (homogeneous) linear constraints arising from reaction irreversibilities and the assumption of steady state; however, other (inhomogeneous) linear constraints, such as minimal and maximal reaction rates frequently used by other constraint-based techniques (such as flux balance analysis [FBA]), cannot be directly integrated. These additional constraints further restrict the space of feasible flux vectors and turn the flux cone into a general flux polyhedron in which the concept of EFMs is not directly applicable anymore. For this reason, there has been a conceptual gap between EFM-based (pathway) analysis methods and linear optimization (FBA) techniques, as they operate on different geometric objects. One approach to overcome these limitations was proposed ten years ago and is based on the concept of elementary flux vectors (EFVs). Only recently has the community started to recognize the potential of EFVs for metabolic network analysis. In fact, EFVs exactly represent the conceptual development required to generalize the idea of EFMs from flux cones to flux polyhedra. This work aims to present a concise theoretical and practical introduction to EFVs that is accessible to a broad audience. We highlight the close relationship between EFMs and EFVs and demonstrate that almost all applications of EFMs (in flux cones) are possible for EFVs (in flux polyhedra) as well. In fact, certain properties can only be studied with EFVs. Thus, we conclude that EFVs provide a powerful and unifying framework for constraint-based modeling of metabolic networks. PMID:28406903

  5. Measurement of a surface heat flux and temperature

    Science.gov (United States)

    Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

    1994-04-01

    superimposed thin-film pattern of all six layers is presented. The large pads are for connection with pins used to bring the signal out the back of the ceramic. flux measurement, the surface temperature is measured with a platinum resistance layer (RTS). &The resistance of this layer increases with increasing temperature. Therefore, these gages simultaneously measure the surface temperature and heat flux. The demonstrated applications include rocket nozzles, SCRAM jet engines, gas turbine engines, boiling heat transfer, flame experiments, basic fluid heat transfer, hypersonic flight, and shock tube testing. *The laboratory involves using one of these sensors in a small combustion flame. -The sensor is made on a 2.5 cm diameter piece of aluminum nitride ceramic.

  6. Coherent Structures and Spectral Energy Transfer in Turbulent Plasma: A Space-Filter Approach

    Science.gov (United States)

    Camporeale, E.; Sorriso-Valvo, L.; Califano, F.; Retinò, A.

    2018-03-01

    Plasma turbulence at scales of the order of the ion inertial length is mediated by several mechanisms, including linear wave damping, magnetic reconnection, the formation and dissipation of thin current sheets, and stochastic heating. It is now understood that the presence of localized coherent structures enhances the dissipation channels and the kinetic features of the plasma. However, no formal way of quantifying the relationship between scale-to-scale energy transfer and the presence of spatial structures has been presented so far. In the Letter we quantify such a relationship analyzing the results of a two-dimensional high-resolution Hall magnetohydrodynamic simulation. In particular, we employ the technique of space filtering to derive a spectral energy flux term which defines, in any point of the computational domain, the signed flux of spectral energy across a given wave number. The characterization of coherent structures is performed by means of a traditional two-dimensional wavelet transformation. By studying the correlation between the spectral energy flux and the wavelet amplitude, we demonstrate the strong relationship between scale-to-scale transfer and coherent structures. Furthermore, by conditioning one quantity with respect to the other, we are able for the first time to quantify the inhomogeneity of the turbulence cascade induced by topological structures in the magnetic field. Taking into account the low space-filling factor of coherent structures (i.e., they cover a small portion of space), it emerges that 80% of the spectral energy transfer (both in the direct and inverse cascade directions) is localized in about 50% of space, and 50% of the energy transfer is localized in only 25% of space.

  7. Flux trapping in superconducting cavities

    International Nuclear Information System (INIS)

    Vallet, C.; Bolore, M.; Bonin, B.; Charrier, J.P.; Daillant, B.; Gratadour, J.; Koechlin, F.; Safa, H.

    1992-01-01

    The flux trapped in various field cooled Nb and Pb samples has been measured. For ambient fields smaller than 3 Gauss, 100% of the flux is trapped. The consequences of this result on the behavior of superconducting RF cavities are discussed. (author) 12 refs.; 2 figs

  8. Squeezing Flux Out of Fat

    DEFF Research Database (Denmark)

    Gonzalez-Franquesa, Alba; Patti, Mary-Elizabeth

    2018-01-01

    Merging transcriptomics or metabolomics data remains insufficient for metabolic flux estimation. Ramirez et al. integrate a genome-scale metabolic model with extracellular flux data to predict and validate metabolic differences between white and brown adipose tissue. This method allows both metab...

  9. Data Acquisition and Flux Calculations

    DEFF Research Database (Denmark)

    Rebmann, C.; Kolle, O; Heinesch, B

    2012-01-01

    In this chapter, the basic theory and the procedures used to obtain turbulent fluxes of energy, mass, and momentum with the eddy covariance technique will be detailed. This includes a description of data acquisition, pretreatment of high-frequency data and flux calculation....

  10. Solar proton fluxes since 1956

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1977-01-01

    The fluxes of protons emitted during solar flares since 1956 were evaluated. The depth-versus-activity profiles of 56 Co in several lunar rocks are consistent with the solar-proton fluxes detected by experiments on several satellites. Only about 20% of the solar-proton-induced activities of 22 Na and 55 Fe in lunar rocks from early Apollo missions were produced by protons emitted from the sun during solar cycle 20 (1965--1975). The depth-versus-activity data for these radionuclides in several lunar rocks were used to determine the fluxes of protons during solar cycle 19 (1954--1964). The average proton fluxes for cycle 19 are about five times those for both the last million years and for cycle 20. These solar-proton flux variations correlate with changes in sunspot activity

  11. Use of images of ictal-inter-ictal SPECT subtraction superimposed on MRI in pharmaco-resistant partial epilepsies in infants

    International Nuclear Information System (INIS)

    Vera, P.; Kaminska, A.; Cieuta, C.; Mangin, F.; Frouin, V.; Dulac, O.; Chiron, C.

    1997-01-01

    To study the significance of ictal SPECT in the pre-surgical examination of infant epilepsies we have explored 16 infants aged 3 months to 18 years presenting partial pharmaco-resistant epilepsy. All of them have had an ictal SPECT under EEG - video recording than, two days after, an inter-ictal SPECT coupled to a 3D cerebral MRI. The perfusion tracer, the 99m Tc - ECD, was injected in average at 15 seconds after the outset of crisis. The image processing implied a matching of the two SPECT examinations by a 3D rigid superposition method, a normalization and than a inter-ictal-ictal image subtraction. Finally, the subtraction was matched and superimposed on the MRI. The SPECT subtraction image showed one or several centres of ictal hyper-output in 15 patients, while the separated visual ictal and inter-ictal images were contributory in 8 cases only. The 16. infant presented very short crises (<10 sec). In the cases when the outset point of crises could be established clinically (12 cases) and/or on EEG (8 cases) a hyper-output of concordant localization was recorded. In 5 infants who have had an electrocorticography, a concordance was obtained in all the cases except in an infant having very short crises the subtraction image did not show hyper-output. These preliminary results show that the ictal - inter-ictal SPECT subtraction images, adjusted on MRI, appears to be reliable in detecting the outset point of crises in infants and at the same time useful in guiding the positioning of intra-cranial electrodes prior to surgery intervention

  12. An incidental enterocolic lymphocytic phlebitis pattern is seen commonly in the rectal stump of patients with diversion colitis superimposed on inflammatory bowel disease.

    Science.gov (United States)

    Chetty, R; Hafezi, S; Montgomery, E

    2009-05-01

    Enterocolic lymphocytic phlebitis (ELP) is an uncommon cause of bowel pathology and most frequently results in ischaemia. It is characterised by an artery-sparing, venulocentric lymphoid infiltrate that causes a phlebitis and vascular compromise. Rare cases of ELP have been encountered with lymphocytic colitis in the absence of ischaemic bowel change. The present study examined the occurrence of ELP in the setting of diversion colitis and inflammatory bowel disease, as well as in random colectomy specimens. The study cohort comprised the following: 26 completion proctectomy specimens for ulcerative colitis with superimposed diversion colitis in the rectal stump; 3 colectomy specimens for Crohn disease with diversion colitis; 6 colectomy specimens for adenocarcinoma and/or diverticular disease with diversion colitis; 34 resection specimens with ulcerative colitis only; 19 with Crohn disease only; and 100 random colon resection specimens for adenocarcinoma, adenoma, diverticular disease and ischaemia. ELP was present in 18 of the 26 ulcerative colitis cases with diversion colitis, 3/3 Crohn disease cases with diversion colitis, 1/6 cases of diverticular disease with diversion colitis, 6/34 cases of ulcerative colitis without diversion, 2/19 Crohn disease cases without diversion colitis, and only 1 of 100 colectomy cases without inflammatory bowel disease or diversion colitis. ELP occurs most frequently in cases that have been diverted for inflammatory bowel disease. Fewer cases of ELP were noted in cases of inflammatory bowel disease in the absence of diversion colitis. It is postulated that altered bowel flora and immune dysregulation may be pivotal in the causation of this association.

  13. Gene expression profile associated with superimposed non-alcoholic fatty liver disease and hepatic fibrosis in patients with chronic hepatitis C.

    Science.gov (United States)

    Younossi, Zobair M; Afendy, Arian; Stepanova, Maria; Hossain, Noreen; Younossi, Issah; Ankrah, Kathy; Gramlich, Terry; Baranova, Ancha

    2009-10-01

    Hepatic steatosis occurs in 40-70% of patients chronically infected with hepatitis C virus [chronic hepatitis C (CH-C)]. Hepatic steatosis in CH-C is associated with progressive liver disease and a low response rate to antiviral therapy. Gene expression profiles were examined in CH-C patients with and without hepatic steatosis, non-alcoholic steatohepatitis (NASH) and fibrosis. This study included 65 CH-C patients who were not receiving antiviral treatment. Total RNA was extracted from peripheral blood mononuclear cells, quantified and used for one-step reverse transcriptase-polymerase chain reaction to profile 153 mRNAs that were normalized with six 'housekeeping' genes and a reference RNA. Multiple regression and stepwise selection assessed differences in gene expression and the models' performances were evaluated. Models predicting the grade of hepatic steatosis in patients with CH-C genotype 3 involved two genes: SOCS1 and IFITM1, which progressively changed their expression level with the increasing grade of steatosis. On the other hand, models predicting hepatic steatosis in non-genotype 3 patients highlighted MIP-1 cytokine encoding genes: CCL3 and CCL4 as well as IFNAR and PRKRIR. Expression levels of PRKRIR and SMAD3 differentiated patients with and without superimposed NASH only in the non-genotype 3 cohort (area under the receiver operating characteristic curve=0.822, P-value 0.006]. Gene expression signatures related to hepatic fibrosis were not genotype specific. Gene expression might predict moderate to severe hepatic steatosis, NASH and fibrosis in patients with CH-C, providing potential insights into the pathogenesis of hepatic steatosis and fibrosis in these patients.

  14. A general approach to flaw simulation in castings by superimposing projections of 3D models onto real X-ray images

    International Nuclear Information System (INIS)

    Hahn, D.; Mery, D.

    2003-01-01

    In order to evaluate the sensitivity of defect inspection systems, it is convenient to examine simulated data. This gives the possibility to tune the parameters of the inspection method and to test the performance of the system in critical cases. In this paper, a practical method for the simulation of defects in radioscopic images of aluminium castings is presented. The approach simulates only the flaws and not the whole radioscopic image of the object under test. A 3D mesh is used to model a flaw with complex geometry, which is projected and superimposed onto real radioscopic images of a homogeneous object according to the exponential attenuation law for X- rays. The new grey value of a pixel, where the 3D flaw is projected, depends only on four parameters: (a) the grey value of the original X-ray image without flaw; (b) the linear absorption coefficient of the examined material; (c) the maximal thickness observable in the radioscopic image; and (d) the length of the intersection of the 3D flaw with the modelled X-ray beam, that is projected into the pixel. A simulation of a complex flaw modelled as a 3D mesh can be performed in any position of the castings by using the algorithm described in this paper. This allows the evaluation of the performance of defect inspection systems in cases where the detection is known to be difficult. In this paper, we show experimental results on real X-ray images of aluminium wheels, in which 3D flaws like blowholes, cracks and inclusions are simulated

  15. Delirium superimposed on dementia: phenomenological differences between patients with and without behavioral and psychological symptoms of dementia in a specialized delirium unit.

    Science.gov (United States)

    Abengaña, Jennifer; Chong, Mei Sian; Tay, Laura

    2017-03-01

    Overlap between neuropsychiatric symptoms of dementia and delirium complicates diagnosis of delirium superimposed on dementia (DSD). This study sought to examine differences in delirium presentation and outcomes between DSD patients with and without pre-existing behavioral and psychological symptoms of dementia (BPSD). This was a prospective cohort study of older adults with DSD admitted to a specialized delirium unit (December 2010-August 2012). We collected data on demographics, comorbidities, illness severity, delirium precipitants, and cognitive and functional scores. Delirium severity was assessed using Delirium Rating Scale Revised-98 (DRS-R-98) and Cognitive Assessment Method severity score (CAM-sev). Patients were categorized as DSD-BPSD+ and DSD-BPSD- based on elicited behavioral and psychological disturbances. We recruited 174 patients with DSD (84.4 +/-7.4 years) with 37 (21.3%) having BPSD. At presentation, delirium severity and symptom frequency on DRS-R98 were similar, but DSD-BPSD+ more often required only a single precipitant (40.5% vs. 21.9%, p = 0.07), and had significantly longer delirium duration (median days: 7 vs. 5, p delirium resolution, DSD-BPSD+ exhibited significant improvement in sleep-wake disturbances (89.2% vs. 54.1%, p symptoms except motor retardation were improved in DSD-BPSD-. Pharmacological restraint was more prevalent (62.2% vs. 40.1%, p = 0.03), and at higher doses (chlorpromazine equivalents 0.95 +/-1.8 vs. 0.40 +/-1.2, p delirium, with subsequent slower delirium recovery. Aggravation of sleep disturbance, labile affect, and motor agitation should raise suspicion for delirium among these patients.

  16. Modeling coherent errors in quantum error correction

    Science.gov (United States)

    Greenbaum, Daniel; Dutton, Zachary

    2018-01-01

    Analysis of quantum error correcting codes is typically done using a stochastic, Pauli channel error model for describing the noise on physical qubits. However, it was recently found that coherent errors (systematic rotations) on physical data qubits result in both physical and logical error rates that differ significantly from those predicted by a Pauli model. Here we examine the accuracy of the Pauli approximation for noise containing coherent errors (characterized by a rotation angle ɛ) under the repetition code. We derive an analytic expression for the logical error channel as a function of arbitrary code distance d and concatenation level n, in the small error limit. We find that coherent physical errors result in logical errors that are partially coherent and therefore non-Pauli. However, the coherent part of the logical error is negligible at fewer than {ε }-({dn-1)} error correction cycles when the decoder is optimized for independent Pauli errors, thus providing a regime of validity for the Pauli approximation. Above this number of correction cycles, the persistent coherent logical error will cause logical failure more quickly than the Pauli model would predict, and this may need to be combated with coherent suppression methods at the physical level or larger codes.

  17. Long-lived coherence in carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J A; Cannon, E; Van Dao, L; Hannaford, P [ARC Centre of Excellence for Coherent X-ray Science, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Victoria 3122 (Australia); Quiney, H M; Nugent, K A, E-mail: jdavis@swin.edu.a [ARC Centre of Excellence for Coherent X-ray Science, School of Physics, University of Melbourne, Victoria 3010 (Australia)

    2010-08-15

    We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the (S{sub 2}|S{sub 0}) superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

  18. Coherent x-rays from PEP

    International Nuclear Information System (INIS)

    Baird, S.; Nuhn, H.-D.; Tatchyn, R.; Winick, H.; Fisher, A.S.; Gallardo, J.C.; Pellegrini, C.

    1991-01-01

    This paper explores the use of a large-circumference, high-energy, electron-positron collider such as PEP to drive a free-electron laser (FEL), producing high levels of coherent power at short wavelengths. The author consider Self-Amplified Spontaneous Emission (SASE), in which electron bunches with low emittance, high peak current and small energy spread radiate coherently in a single passthrough a long undulator. As the electron beam passes down the undulator, its interaction with the increasingly intense spontaneous radiation causes a bunch density modulation at the optical wavelength, resulting in stimulated emissional growth of coherent power in a single pass. The need for optical-cavity mirrors, which place a lower limit on the wavelength of a conventional FEL oscillator, is avoided. The authors explore various combinations of electron-beam and undulator parameters, as well as special undulator designs and optical klystrons (OK), to reach high average or peak coherent power at wavelengths around 40 angstrom by achieving significant exponential gain or full saturation. Examples are presented for devices that achieve high peak coherent power (up to about 400 MW) with lower average coherent power (about 20 mW) and other devices which produce a few watts of average coherent power

  19. Optical Coherence Tomography of the Aging Kidney.

    Science.gov (United States)

    Andrews, Peter M; Wang, Hsing-Wen; Guo, Hengchang; Anderson, Erik; Falola, Reuben; Chen, Yu

    2016-12-01

    The aging kidney exhibits a progressive decline in renal function with characteristic histopathologic changes and is a risk factor for renal transplant. However, the degree to which the kidney exhibits this decline depends on several factors that vary from one individual to the next. Optical coherence tomography is an evolving noninvasive imaging technology that has recently been used to evaluate acute tubular necrosis of living-human donor kidneys before their transplant. With the increasing use of kidneys from older individuals, it is important to determine whether optical coherence tomography also can distinguish the histopathology associated with aging. In this investigation, we used Munich-Wistar rats to evaluate the ability of optical coherence tomography to detect histopathologic changes associated with aging. Optical coherence tomography observations were correlated with renal function and conventional light microscopic evaluation of these same kidneys. With the onset of severe proteinuria at 10 to 12 months of age, optical coherence tomography revealed tubular necrosis/atrophy, interstitial fibrosis, tubular dilation, and glomerulosclerosis. With a further deterioration in kidney function at 16 to 18 months of age (as indicated by rising creatinine levels), optical coherence tomography revealed more extensive interstitial fibrosis and tubular atrophy, increased tubular dilation with cyst formation and more sclerotic glomeruli. The foregoing observations suggest that optical coherence tomography can be used to detect the histopathology of progressive nephropathy associated with aging.

  20. Exergy of partially coherent thermal radiation

    International Nuclear Information System (INIS)

    Wijewardane, S.; Goswami, Yogi

    2012-01-01

    Exergy of electromagnetic radiation has been studied by a number of researchers for well over four decades in order to estimate the maximum conversion efficiencies of thermal radiation. As these researchers primarily dealt with solar and blackbody radiation, which have a low degree of coherence, they did not consider the partial coherence properties of thermal radiation. With the recent development of surface structures, which can emit radiation with high degree of coherence, the importance of considering the partial coherent properties in exergy calculation has become a necessity as the coherence properties directly influence the entropy of the wave field. Here in this paper we derive an expression for the exergy of quasi-monochromatic radiation using statistical thermodynamics and show that it is identical with the expressions derived using classical thermodynamics. We also present a method to calculate the entropy, thereby the exergy of partially coherent radiation using statistical thermodynamics and a method called matrix treatment of wave field. -- Highlights: ► Considered partial coherence of radiation for the first time to calculate exergy. ► The importance of this method is emphasized with energy conversion examples. ► Derived an expression for the exergy of radiation using statistical thermodynamics. ► Adopted a method to calculate intensity of statistically independent principle wave.

  1. Coherence and correspondence in engineering design

    Directory of Open Access Journals (Sweden)

    Konstantinos V. Katsikopoulos

    2009-03-01

    Full Text Available I show how the coherence/correspondence distinction can inform the conversation about decision methods for engineering design. Some engineers argue for the application of multi-attribute utility theory while others argue for what they call heuristics. To clarify the differences among methods, I first ask whether each method aims at achieving coherence or correspondence. By analyzing statements in the design literature, I argue that utility theory aims at achieving coherence and heuristics aim at achieving correspondence. Second, I ask if achieving coherence always implies achieving correspondence. It is important to provide an answer because while in design the objective is correspondence, it is difficult to assess it, and coherence that is easier to assess is used as a surrogate. I argue that coherence does not always imply correspondence in design and that this is also the case in problems studied in judgment and decision-making research. Uncovering the conditions under which coherence implies, or does not imply, correspondence is a topic where engineering design and judgment and decision-making research might connect.

  2. Long-lived coherence in carotenoids

    International Nuclear Information System (INIS)

    Davis, J A; Cannon, E; Van Dao, L; Hannaford, P; Quiney, H M; Nugent, K A

    2010-01-01

    We use two-colour vibronic coherence spectroscopy to observe long-lived vibrational coherences in the ground electronic state of carotenoid molecules, with decoherence times in excess of 1 ps. Lycopene and spheroidene were studied isolated in solution, and within the LH2 light-harvesting complex extracted from purple bacteria. The vibrational coherence time is shown to increase significantly for the carotenoid in the complex, providing further support to previous assertions that long-lived electronic coherences in light-harvesting complexes are facilitated by in-phase motion of the chromophores and surrounding proteins. Using this technique, we are also able to follow the evolution of excited state coherences and find that for carotenoids in the light-harvesting complex the (S 2 |S 0 ) superposition remains coherent for more than 70 fs. In addition to the implications of this long electronic decoherence time, the extended coherence allows us to observe the evolution of the excited state wavepacket. These experiments reveal an enhancement of the vibronic coupling to the first vibrational level of the C-C stretching mode and/or methyl-rocking mode in the ground electronic state 70 fs after the initial excitation. These observations open the door to future experiments and modelling that may be able to resolve the relaxation dynamics of carotenoids in solution and in natural light-harvesting systems.

  3. A state-space modeling approach to estimating canopy conductance and associated uncertainties from sap flux density data

    Science.gov (United States)

    David M. Bell; Eric J. Ward; A. Christopher Oishi; Ram Oren; Paul G. Flikkema; James S. Clark; David Whitehead

    2015-01-01

    Uncertainties in ecophysiological responses to environment, such as the impact of atmospheric and soil moisture conditions on plant water regulation, limit our ability to estimate key inputs for ecosystem models. Advanced statistical frameworks provide coherent methodologies for relating observed data, such as stem sap flux density, to unobserved processes, such as...

  4. Partial coherence with application to the monotonicity problem of coherence involving skew information

    Science.gov (United States)

    Luo, Shunlong; Sun, Yuan

    2017-08-01

    Quantifications of coherence are intensively studied in the context of completely decoherent operations (i.e., von Neuamnn measurements, or equivalently, orthonormal bases) in recent years. Here we investigate partial coherence (i.e., coherence in the context of partially decoherent operations such as Lüders measurements). A bona fide measure of partial coherence is introduced. As an application, we address the monotonicity problem of K -coherence (a quantifier for coherence in terms of Wigner-Yanase skew information) [Girolami, Phys. Rev. Lett. 113, 170401 (2014), 10.1103/PhysRevLett.113.170401], which is introduced to realize a measure of coherence as axiomatized by Baumgratz, Cramer, and Plenio [Phys. Rev. Lett. 113, 140401 (2014), 10.1103/PhysRevLett.113.140401]. Since K -coherence fails to meet the necessary requirement of monotonicity under incoherent operations, it is desirable to remedy this monotonicity problem. We show that if we modify the original measure by taking skew information with respect to the spectral decomposition of an observable, rather than the observable itself, as a measure of coherence, then the problem disappears, and the resultant coherence measure satisfies the monotonicity. Some concrete examples are discussed and related open issues are indicated.

  5. Current density waves in open mesoscopic rings driven by time-periodic magnetic fluxes

    International Nuclear Information System (INIS)

    Yan Conghua; Wei Lianfu

    2010-01-01

    Quantum coherent transport through open mesoscopic Aharonov-Bohm rings (driven by static fluxes) have been studied extensively. Here, by using quantum waveguide theory and the Floquet theorem we investigate the quantum transport of electrons along an open mesoscopic ring threaded by a time-periodic magnetic flux. We predicate that current density waves could be excited along such an open ring. As a consequence, a net current could be generated along the lead with only one reservoir, if the lead additionally connects to such a normal-metal loop driven by the time-dependent flux. These phenomena could be explained by photon-assisted processes, due to the interaction between the transported electrons and the applied oscillating external fields. We also discuss how the time-average currents (along the ring and the lead) depend on the amplitude and frequency of the applied oscillating fluxes.

  6. Fractional flux excitations and flux creep in a superconducting film

    International Nuclear Information System (INIS)

    Lyuksyutov, I.F.

    1995-01-01

    We consider the transport properties of a modulated superconducting film in a magnetic field parallel to the film. Modulation can be either intrinsic, due to the layered structure of the high-T c superconductors, or artificial, e.g. due to thickness modulation. This system has an infinite set ( >) of pinned phases. In the pinned phase the excitation of flux loops with a fractional number of flux quanta by the applied current j results in flux creep with a generated voltage V ∝ exp[-jo/j[. (orig.)

  7. Coherent and squeezed states in phase space

    International Nuclear Information System (INIS)

    Jannussis, A.; Bartzis, V.; Vlahos, E.

    1990-01-01

    In the present paper, the coherent and the squeezed states in phase space have been studied. From the wave functions of the coherent and the squeezed state, their corresponding Wigner distribution functions are calculated. Especially the calculation of the corresponding Wigner functions for the above states permits the determination of the mean values of position and momentum and thus the Heisenberg uncertainty relation. In fact, from the related results, it is concluded that the uncertainty relation of the coherent and associated squeezed states is the same

  8. Coherence and extensions of stochastic matrices

    Directory of Open Access Journals (Sweden)

    Angelo Gilio

    1995-11-01

    Full Text Available In this paper a review of some general results on coherence of conditional probability assessments is given. Then, a necessary and sufficient condition on coherence of two finite families of discrete conditianal probability distributions, represented by two stochastic matrices P and Q, is obtained. Moreover, the possible extensions of the assessment (P,Q to the marginal distributions are examined and explicit formulas for them are given in some special case. Finally, a general algorithm to check coherence of (P,Q and to derive its extensions is proposed.

  9. Coherent states in quaternionic quantum mechanics

    International Nuclear Information System (INIS)

    Adler, S.L.; Millard, A.C.

    1997-01-01

    We develop Perelomov close-quote s coherent states formalism to include the case of a quaternionic Hilbert space. We find that, because of the closure requirement, an attempted quaternionic generalization of the special nilpotent or Weyl group reduces to the normal complex case. For the case of the compact group SU(2), however, coherent states can be formulated using the quaternionic half-integer spin matrices of Finkelstein, Jauch, and Speiser, giving a nontrivial quaternionic analog of coherent states. copyright 1997 American Institute of Physics

  10. Coherent Lagrangian swirls among submesoscale motions.

    Science.gov (United States)

    Beron-Vera, F J; Hadjighasem, A; Xia, Q; Olascoaga, M J; Haller, G

    2018-03-05

    The emergence of coherent Lagrangian swirls (CLSs) among submesoscale motions in the ocean is illustrated. This is done by applying recent nonlinear dynamics tools for Lagrangian coherence detection on a surface flow realization produced by a data-assimilative submesoscale-permitting ocean general circulation model simulation of the Gulf of Mexico. Both mesoscale and submesoscale CLSs are extracted. These extractions prove the relevance of coherent Lagrangian eddies detected in satellite-altimetry-based geostrophic flow data for the arguably more realistic ageostrophic multiscale flow.

  11. Diffusion tensor optical coherence tomography

    Science.gov (United States)

    Marks, Daniel L.; Blackmon, Richard L.; Oldenburg, Amy L.

    2018-01-01

    In situ measurements of diffusive particle transport provide insight into tissue architecture, drug delivery, and cellular function. Analogous to diffusion-tensor magnetic resonance imaging (DT-MRI), where the anisotropic diffusion of water molecules is mapped on the millimeter scale to elucidate the fibrous structure of tissue, here we propose diffusion-tensor optical coherence tomography (DT-OCT) for measuring directional diffusivity and flow of optically scattering particles within tissue. Because DT-OCT is sensitive to the sub-resolution motion of Brownian particles as they are constrained by tissue macromolecules, it has the potential to quantify nanoporous anisotropic tissue structure at micrometer resolution as relevant to extracellular matrices, neurons, and capillaries. Here we derive the principles of DT-OCT, relating the detected optical signal from a minimum of six probe beams with the six unique diffusion tensor and three flow vector components. The optimal geometry of the probe beams is determined given a finite numerical aperture, and a high-speed hardware implementation is proposed. Finally, Monte Carlo simulations are employed to assess the ability of the proposed DT-OCT system to quantify anisotropic diffusion of nanoparticles in a collagen matrix, an extracellular constituent that is known to become highly aligned during tumor development.

  12. Coherence effects in parton showers

    International Nuclear Information System (INIS)

    Pettersson, U.

    1988-10-01

    A model for gluon emission based on the colour dipole approximation is presented. Gluons are radiated from dipoles that are stretched from one colour charge to the corresponding anti-charge, with probability distribution given by generalizations of the Altarelli-Parisi equations. The model agrees very well with experimental data on e + e - annihilation. For the reaction e + e - -> W + W - -> qq ' QQ ' it is pointed out how to extract information about the QCD vacuum and the confinement mechanism by varying the CM energy. Finally the model is applied to deep inelastic lepton scattering. When a quark is kicked out in the lepton-proton interaction, separation of the colour charges leads to gluon emission. Since the proton remnant is not a pointlike object, coherence conditions lead to an asymmetry between gluons emitted in the forward and in the backward region. The asymmetry is controlled by the energy distribution in the force field. Experimental data are reproduced with a linear energy distribution, which is consistent with the proton behaving as a vortex line in a type II superconductor. (author)

  13. Monte Carlo surface flux tallies

    International Nuclear Information System (INIS)

    Favorite, Jeffrey A.

    2010-01-01

    Particle fluxes on surfaces are difficult to calculate with Monte Carlo codes because the score requires a division by the surface-crossing angle cosine, and grazing angles lead to inaccuracies. We revisit the standard practice of dividing by half of a cosine 'cutoff' for particles whose surface-crossing cosines are below the cutoff. The theory behind this approximation is sound, but the application of the theory to all possible situations does not account for two implicit assumptions: (1) the grazing band must be symmetric about 0, and (2) a single linear expansion for the angular flux must be applied in the entire grazing band. These assumptions are violated in common circumstances; for example, for separate in-going and out-going flux tallies on internal surfaces, and for out-going flux tallies on external surfaces. In some situations, dividing by two-thirds of the cosine cutoff is more appropriate. If users were able to control both the cosine cutoff and the substitute value, they could use these parameters to make accurate surface flux tallies. The procedure is demonstrated in a test problem in which Monte Carlo surface fluxes in cosine bins are converted to angular fluxes and compared with the results of a discrete ordinates calculation.

  14. Coherence and the day-night asymmetry in the solar neutrino flux

    International Nuclear Information System (INIS)

    Dighe, A.S.; Liu, Q.Y.; Smirnov, A.Yu.

    1999-12-01

    We consider the day-night asymmetries predicted by various MSW solutions of the solar neutrino problem. The integration over the neutrino energy, as well as over the production region or over the time intervals of more than a day leads to the averaging of oscillations on the way to the earth. This is equivalent to considering the neutrino state arriving at the surface of the earth as an incoherent mixture of the neutrino mass eigenstates (even if there is no divergence of wavepackets). As a consequence, the regeneration effect inside the earth is incoherent, in contrast with the results in hep-ph/9902435. (author)

  15. Thermal, intermediate and fast neutron flux measurements using activation detectors; Mesure des flux de neutrons thermiques, intermediaires et rapides au moyen de detecteurs par activation

    Energy Technology Data Exchange (ETDEWEB)

    Brisbois, J; Lott, M; Manent, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The problem of neutron flux measurements using activation detectors is studied in the particular case of protection research. It is shown how it possible, it is possible, using a known thermal flux, to organise a coherent calibration system for all the detectors. The rapid neutron detectors are calibrated with respect to a reference detector (phosphorus) in a natural uranium converter; the intermediate neutron detectors with respect to gold in the axial channel of ZOE. This method makes it possible to minimise the errors due to the activation cross-sections. A brief description is given of the counting room of the Pile Safety Study Service, as well of the practical utilisation characteristics of the counters employed. (authors) [French] Le probleme de la mesure des flux de neutrons au moyen de detecteurs par activation est etudie dans le cas particulier des etudes de protections. On montre comment, a partir d'un flux thermique connu, on peut organiser un systeme coherent d'etalonnage de tous les detecteurs. Les detecteurs de neutrons rapides sont etalonnes par rapport a un detecteur de reference (phosphore) dans un convertisseur en uranium naturel; les detecteurs de neutrons intermediaires, par rapport a l'or dans le canal axial de ZOE, Cette methode permet de minimiser les erreurs dues aux sections efficaces d'activation. On decrit sommairement la salle de comptage du Service d'Etudes de Protections de Piles et on indique les caracteristiques d'emploi pratique des detecteurs utilises. (auteurs)

  16. Ptychotomography at DLS Coherence Beamline I13

    Science.gov (United States)

    Kuppili, V. S. C.; Sala, S.; Chalkidis, S.; Wise, A. M.; Parsons, A. D.; Zanette, I.; Rau, C.; Thibault, P.

    2017-06-01

    We describe the implementation and execution of ptychotomography at I13-1, the coherence branchline at Diamond Light Source. The data collection and image reconstruction protocol is demonstrated with the three dimensional reconstruction of a nanoporous gold sample.

  17. Ptychotomography at DLS Coherence Beamline I13

    International Nuclear Information System (INIS)

    Kuppili, V.S.C.; Sala, S.; Chalkidis, S.; Wise, A.M.; Parsons, A.D.; Zanette, I.; Rau, C.; Thibault, P.

    2017-01-01

    We describe the implementation and execution of ptychotomography at I13-1, the coherence branchline at Diamond Light Source. The data collection and image reconstruction protocol is demonstrated with the three dimensional reconstruction of a nanoporous gold sample. (paper)

  18. Managing coherence via put/get windows

    Science.gov (United States)

    Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton on Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Hoenicke, Dirk [Ossining, NY; Ohmacht, Martin [Yorktown Heights, NY

    2011-01-11

    A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

  19. Optical Coherent Receiver Enables THz Wireless Bridge

    DEFF Research Database (Denmark)

    Yu, Xianbin; Liu, Kexin; Zhang, Hangkai

    2016-01-01

    We experimentally demonstrated a 45 Gbit/s 400 GHz photonic wireless communication system enabled by an optical coherent receiver, which has a high potential in fast recovery of high data rate connections, for example, in disaster....

  20. Reaction mechanisms in coherent nuclear photoproduction

    International Nuclear Information System (INIS)

    Lazard, C.

    Nuclear coherent pion photoproduction is studied. Pion rescattering and propagation effects inside nucleus and mesic exchange current effects are discussed. Influence of nuclear wave functions and Fermi motion is presented [fr

  1. Power system coherency and model reduction

    CERN Document Server

    Chow, Joe H

    2014-01-01

    This book provides a comprehensive treatment for understanding interarea modes in large power systems and obtaining reduced-order models using the coherency concept and selective modal analysis method.

  2. Chromatic Dispersion Estimation in Digital Coherent Receivers

    DEFF Research Database (Denmark)

    Soriano, Ruben Andres; Hauske, Fabian N.; Guerrero Gonzalez, Neil

    2011-01-01

    Polarization-diverse coherent demodulation allows to compensate large values of accumulated linear distortion by digital signal processing. In particular, in uncompensated links without optical dispersion compensation, the parameter of the residual chromatic dispersion (CD) is vital to set...

  3. Coherence properties of the radiation from FLASH

    International Nuclear Information System (INIS)

    Schneidmiller, E.A.; Yurkov, M.V.

    2015-02-01

    FLASH is the first free electron laser user facility operating in the vacuum ultraviolet and soft x-ray wavelength range. Many user experiments require knowledge of the spatial and temporal coherence properties of the radiation. In this paper we present an analysis of the coherence properties of the radiation for the fundamental and for the higher odd frequency harmonics. We show that temporal and spatial coherence reach maximum close to the FEL saturation but may degrade significantly in the post-saturation regime. We also find that the pointing stability of short FEL pulses is limited due to the fact that non-azimuthal FEL eigenmodes are not sufficiently suppressed. We discuss possible ways for improving the degree of transverse coherence and the pointing stability.

  4. Programmable and coherent crystallization of semiconductors

    KAUST Repository

    Yu, Liyang; Niazi, Muhammad Rizwan; Ngongang Ndjawa, Guy Olivier; Li, Ruipeng; Kirmani, Ahmad R.; Munir, Rahim; Balawi, Ahmed H.; Laquai, Fré dé ric; Amassian, Aram

    2017-01-01

    and incoherent nucleation events, limiting the ability to control or pattern the microstructure, texture, and functional properties of polycrystalline materials. We present a universal approach that can program the microstructure of materials through the coherent

  5. Restricted Coherent Risk Measures and Actuarial Solvency

    Directory of Open Access Journals (Sweden)

    Christos E. Kountzakis

    2012-01-01

    Full Text Available We prove a general dual representation form for restricted coherent risk measures, and we apply it to a minimization problem of the required solvency capital for an insurance company.

  6. Coherence Phenomena in Coupled Optical Resonators

    Science.gov (United States)

    Smith, D. D.; Chang, H.

    2004-01-01

    We predict a variety of photonic coherence phenomena in passive and active coupled ring resonators. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived, and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. We also demonstrate that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation, and use this result for the analysis of coupled-resonator photon dynamics. Notably, because these effects are predicted directly from coupled-mode theory, they are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators.

  7. Coherence and chaos in condensed matter

    International Nuclear Information System (INIS)

    Bishop, A.R.

    1989-01-01

    This paper discusses the following topics: nonlinearity in condensed matter; coherence and chaos in spatially extended condensed matter systems; nonlinearity and magnetism; and solitons and conducting polymers. 52 refs., 7 figs

  8. Coherent Structures in Numerically Simulated Plasma Turbulence

    DEFF Research Database (Denmark)

    Kofoed-Hansen, O.; Pécseli, H.L.; Trulsen, J.

    1989-01-01

    Low level electrostatic ion acoustic turbulence generated by the ion-ion beam instability was investigated numerically. The fluctuations in potential were investigated by a conditional statistical analysis revealing propagating coherent structures having the form of negative potential wells which...

  9. Overlapped optics induced perfect coherent effects

    Science.gov (United States)

    Li, Jian Jie; Zang, Xiao Fei; Mao, Jun Fa; Tang, Min; Zhu, Yi Ming; Zhuang, Song Lin

    2013-12-01

    For traditional coherent effects, two separated identical point sources can be interfered with each other only when the optical path difference is integer number of wavelengths, leading to alternate dark and bright fringes for different optical path difference. For hundreds of years, such a perfect coherent condition seems insurmountable. However, in this paper, based on transformation optics, two separated in-phase identical point sources can induce perfect interference with each other without satisfying the traditional coherent condition. This shifting illusion media is realized by inductor-capacitor transmission line network. Theoretical analysis, numerical simulations and experimental results are performed to confirm such a kind of perfect coherent effect and it is found that the total radiation power of multiple elements system can be greatly enhanced. Our investigation may be applicable to National Ignition Facility (NIF), Inertial Confined Fusion (ICF) of China, LED lighting technology, terahertz communication, and so on.

  10. Managing coherence via put/get windows

    Science.gov (United States)

    Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton on Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Hoenicke, Dirk [Ossining, NY; Ohmacht, Martin [Yorktown Heights, NY

    2012-02-21

    A method and apparatus for managing coherence between two processors of a two processor node of a multi-processor computer system. Generally the present invention relates to a software algorithm that simplifies and significantly speeds the management of cache coherence in a message passing parallel computer, and to hardware apparatus that assists this cache coherence algorithm. The software algorithm uses the opening and closing of put/get windows to coordinate the activated required to achieve cache coherence. The hardware apparatus may be an extension to the hardware address decode, that creates, in the physical memory address space of the node, an area of virtual memory that (a) does not actually exist, and (b) is therefore able to respond instantly to read and write requests from the processing elements.

  11. Carbon Dioxide Transfer Through Sea Ice: Modelling Flux in Brine Channels

    Science.gov (United States)

    Edwards, L.; Mitchelson-Jacob, G.; Hardman-Mountford, N.

    2010-12-01

    For many years sea ice was thought to act as a barrier to the flux of CO2 between the ocean and atmosphere. However, laboratory-based and in-situ observations suggest that while sea ice may in some circumstances reduce or prevent transfer (e.g. in regions of thick, superimposed multi-year ice), it may also be highly permeable (e.g. thin, first year ice) with some studies observing significant fluxes of CO2. Sea ice covered regions have been observed to act both as a sink and a source of atmospheric CO2 with the permeability of sea ice and direction of flux related to sea ice temperature and the presence of brine channels in the ice, as well as seasonal processes such as whether the ice is freezing or thawing. Brine channels concentrate dissolved inorganic carbon (DIC) as well as salinity and as these dense waters descend through both the sea ice and the surface ocean waters, they create a sink for CO2. Calcium carbonate (ikaite) precipitation in the sea ice is thought to enhance this process. Micro-organisms present within the sea ice will also contribute to the CO2 flux dynamics. Recent evidence of decreasing sea ice extent and the associated change from a multi-year ice to first-year ice dominated system suggest the potential for increased CO2 flux through regions of thinner, more porous sea ice. A full understanding of the processes and feedbacks controlling the flux in these regions is needed to determine their possible contribution to global CO2 levels in a future warming climate scenario. Despite the significance of these regions, the air-sea CO2 flux in sea ice covered regions is not currently included in global climate models. Incorporating this carbon flux system into Earth System models requires the development of a well-parameterised sea ice-air flux model. In our work we use the Los Alamos sea ice model, CICE, with a modification to incorporate the movement of CO2 through brine channels including the addition of DIC processes and ice algae production to

  12. El Naschie's coherence on the subquantum medium

    International Nuclear Information System (INIS)

    Agop, M.; Ioannou, P.D.; Nica, P.; Galusca, G.; Stefan, M.

    2005-01-01

    In the hydrodynamic formulation of the Scale Relativity theory one shows that a stable vortices distribution of bipolaron type induces superconducting pairs by means of the quantum potential. One builds the superconducting fractal by an iterated map and demonstrates that the superconducting pairs results as projections of this fractal. Thus, usual mechanisms (as example the exchange interaction used in the bipolaron theory) are reduced to the coherence on the subquantum medium in a ε (∞) space (El Naschie's coherence)

  13. Coherent Control of Photoelectron Wavepacket Angular Interferograms

    OpenAIRE

    Hockett, Paul; Wollenhaupt, Matthias; Baumert, Thomas

    2015-01-01

    Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the cohere...

  14. Coherent states approach to Penning trap

    International Nuclear Information System (INIS)

    Fernandez, David J; Velazquez, Mercedes

    2009-01-01

    By using a matrix technique, which allows us to identify directly the ladder operators, the Penning trap coherent states are derived as eigenstates of the appropriate annihilation operators. These states are compared with those obtained through the displacement operator. The associated wavefunctions and mean values for some relevant operators in these states are also evaluated. It turns out that the Penning trap coherent states minimize the Heisenberg uncertainty relation

  15. Using nonlocal coherence to quantify quantum correlation

    OpenAIRE

    Pei, Pei; Wang, Wei; Li, Chong; Song, He-Shan

    2010-01-01

    We reexamine quantum correlation from the fundamental perspective of its consanguineous quantum property, the coherence. We emphasize the importance of specifying the tensor product structure of the total state space before discussing quantum correlation. A measure of quantum correlation for arbitrary dimension bipartite states using nonlocal coherence is proposed, and it can be easily generalized to the multipartite case. The quantification of non-entangled component within quantum correlati...

  16. Evidence for color coherence in jet events

    Energy Technology Data Exchange (ETDEWEB)

    CDF Collaboration

    1994-06-01

    Color coherence effects in p{bar p} collisions are observed and studied with CDF, the Collider Detector at the Fermilab Tevatron collider. We demonstrate these effects by measuring spatial correlations between soft and leading jets in multi jet events. Variables sensitive to interference are identified by comparing the data to the predictions of various shower Monte Carlos that are substantially different with respect to the implementation of coherence.

  17. Coherent structures in tokamak plasmas workshop: Proceedings

    International Nuclear Information System (INIS)

    Koniges, A.E.; Craddock, G.G.

    1992-08-01

    Coherent structures have the potential to impact a variety of theoretical and experimental aspects of tokamak plasma confinement. This includes the basic processes controlling plasma transport, propagation and efficiency of external mechanisms such as wave heating and the accuracy of plasma diagnostics. While the role of coherent structures in fluid dynamics is better understood, this is a new topic for consideration by plasma physicists. This informal workshop arose out of the need to identify the magnitude of structures in tokamaks and in doing so, to bring together for the first time the surprisingly large number of plasma researchers currently involved in work relating to coherent structures. The primary purpose of the workshop, in addition to the dissemination of information, was to develop formal and informal collaborations, set the stage for future formation of a coherent structures working group or focus area under the heading of the Tokamak Transport Task Force, and to evaluate the need for future workshops on coherent structures. The workshop was concentrated in four basic areas with a keynote talk in each area as well as 10 additional presentations. The issues of discussion in each of these areas was as follows: Theory - Develop a definition of structures and coherent as it applies to plasmas. Experiment - Review current experiments looking for structures in tokamaks, discuss experimental procedures for finding structures, discuss new experiments and techniques. Fluids - Determine how best to utilize the resource of information available from the fluids community both on the theoretical and experimental issues pertaining to coherent structures in plasmas. Computation - Discuss computational aspects of studying coherent structures in plasmas as they relate to both experimental detection and theoretical modeling

  18. Analytic coherent states for generalized potentials

    International Nuclear Information System (INIS)

    Nieto, M.M.; Simmons, L.M. Jr.

    1978-01-01

    A prescription is given for finding coherent states in generalized potentials. By coherent states is meant states which in time follow the motion that a classical particle would. This prescription is based upon finding those natural classical variables which vary as the sine and the cosine of the classical ω/sub c/t. As an example, the symmetric Rosen--Morse potential is discussed in detail

  19. Coherent states, pseudodifferential analysis and arithmetic

    Science.gov (United States)

    Unterberger, André

    2012-06-01

    Basic questions regarding families of coherent states include describing some constructions of such and the way they can be applied to operator theory or partial differential equations. In both questions, pseudodifferential analysis is important. Recent developments indicate that they can contribute to methods in arithmetic, especially modular form theory. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’.

  20. Gradiometric tunable-gap flux qubits in a circuit QED architecture

    International Nuclear Information System (INIS)

    Schwarz, Manuel Johannes

    2015-01-01

    In circuit quantum electrodynamics or quantum simulation experiments, superconducting quantum bits with long coherence time, high in situ tunability and usually large anharmonicity are required. In contrast to the popular transmon, the gradiometric tunable-gap flux qubit meets all these requirements. We fabricate and characterize such a qubit and demonstrate its first implementation into a transmission line resonator. We show spectroscopy and first time domain results.

  1. Teleportation of a Coherent Superposition State Via a nonmaximally Entangled Coherent Xhannel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ We investigate the problemm of teleportation of a superposition coherent state with nonmaximally entangled coherent channel. Two strategies are considered to complete the task. The first one uses entanglement concentration to purify the channel to a maximally entangled one. The second one teleports the state through the nonmaximally entangled coherent channel directly. We find that the probabilities of successful teleportations for the two strategies are depend on the amplitudes of the coherent states and the mean fidelity of teleportation using the first strategy is always less than that of the second strategy.

  2. Linear algebraic theory of partial coherence: discrete fields and measures of partial coherence.

    Science.gov (United States)

    Ozaktas, Haldun M; Yüksel, Serdar; Kutay, M Alper

    2002-08-01

    A linear algebraic theory of partial coherence is presented that allows precise mathematical definitions of concepts such as coherence and incoherence. This not only provides new perspectives and insights but also allows us to employ the conceptual and algebraic tools of linear algebra in applications. We define several scalar measures of the degree of partial coherence of an optical field that are zero for full incoherence and unity for full coherence. The mathematical definitions are related to our physical understanding of the corresponding concepts by considering them in the context of Young's experiment.

  3. Painlevé IV coherent states

    International Nuclear Information System (INIS)

    Bermudez, David; Contreras-Astorga, Alonso; Fernández C, David J.

    2014-01-01

    A simple way to find solutions of the Painlevé IV equation is by identifying Hamiltonian systems with third-order differential ladder operators. Some of these systems can be obtained by applying supersymmetric quantum mechanics (SUSY QM) to the harmonic oscillator. In this work, we will construct families of coherent states for such subset of SUSY partner Hamiltonians which are connected with the Painlevé IV equation. First, these coherent states are built up as eigenstates of the annihilation operator, then as displaced versions of the extremal states, both involving the related third-order ladder operators, and finally as extremal states which are also displaced but now using the so called linearized ladder operators. To each SUSY partner Hamiltonian corresponds two families of coherent states: one inside the infinite subspace associated with the isospectral part of the spectrum and another one in the finite subspace generated by the states created through the SUSY technique. - Highlights: • We use SUSY QM to obtain Hamiltonians with third-order differential ladder operators. • We show that these systems are related with the Painlevé IV equation. • We apply different definitions of coherent states to these Hamiltonians using the third-order ladder operators and some linearized ones. • We construct families of coherent states for such systems, which we called Painlevé IV coherent states

  4. Painlevé IV coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, David, E-mail: david.bermudez@weizmann.ac.il [Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100 (Israel); Departamento de Física, Cinvestav, A.P. 14-740, 07000 México D.F. (Mexico); Contreras-Astorga, Alonso, E-mail: aloncont@iun.edu [Department of Mathematics and Actuarial Science, Indiana University Northwest, 3400 Broadway, Gary IN 46408 (United States); Departamento de Física, Cinvestav, A.P. 14-740, 07000 México D.F. (Mexico); Fernández C, David J., E-mail: david@fis.cinvestav.mx [Departamento de Física, Cinvestav, A.P. 14-740, 07000 México D.F. (Mexico)

    2014-11-15

    A simple way to find solutions of the Painlevé IV equation is by identifying Hamiltonian systems with third-order differential ladder operators. Some of these systems can be obtained by applying supersymmetric quantum mechanics (SUSY QM) to the harmonic oscillator. In this work, we will construct families of coherent states for such subset of SUSY partner Hamiltonians which are connected with the Painlevé IV equation. First, these coherent states are built up as eigenstates of the annihilation operator, then as displaced versions of the extremal states, both involving the related third-order ladder operators, and finally as extremal states which are also displaced but now using the so called linearized ladder operators. To each SUSY partner Hamiltonian corresponds two families of coherent states: one inside the infinite subspace associated with the isospectral part of the spectrum and another one in the finite subspace generated by the states created through the SUSY technique. - Highlights: • We use SUSY QM to obtain Hamiltonians with third-order differential ladder operators. • We show that these systems are related with the Painlevé IV equation. • We apply different definitions of coherent states to these Hamiltonians using the third-order ladder operators and some linearized ones. • We construct families of coherent states for such systems, which we called Painlevé IV coherent states.

  5. Polarization Sensitive Coherent Raman Measurements of DCVJ

    Science.gov (United States)

    Anderson, Josiah; Cooper, Nathan; Lawhead, Carlos; Shiver, Tegan; Ujj, Laszlo

    2014-03-01

    Coherent Raman spectroscopy which recently developed into coherent Raman microscopy has been used to produce label free imaging of thin layers of material and find the spatial distributions of certain chemicals within samples, e.g. cancer cells.(1) Not all aspects of coherent scattering have been used for imaging. Among those for example are special polarization sensitive measurements. Therefore we have investigated the properties of polarization sensitive CARS spectra of a highly fluorescent molecule, DCVJ.(2) Spectra has been recorded by using parallel polarized and perpendicular polarized excitations. A special polarization arrangement was developed to suppress the non-resonant background scattering from the sample. These results can be used to improve the imaging properties of a coherent Raman microscope in the future. This is the first time coherent Raman polarization sensitive measurements have been used to characterize the vibrational modes of DCVJ. 1: K. I. Gutkowski, et al., ``Fluorescence of dicyanovinyl julolidine in a room temperature ionic liquid '' Chemical Physics Letters 426 (2006) 329 - 333 2: Fouad El-Diasty, ``Coherent anti-Stokes Raman scattering: Spectroscopy and microscopy'' Vibrational Spectroscopy 55 (2011) 1-37

  6. Evaluating Extensions to Coherent Mortality Forecasting Models

    Directory of Open Access Journals (Sweden)

    Syazreen Shair

    2017-03-01

    Full Text Available Coherent models were developed recently to forecast the mortality of two or more sub-populations simultaneously and to ensure long-term non-divergent mortality forecasts of sub-populations. This paper evaluates the forecast accuracy of two recently-published coherent mortality models, the Poisson common factor and the product-ratio functional models. These models are compared to each other and the corresponding independent models, as well as the original Lee–Carter model. All models are applied to age-gender-specific mortality data for Australia and Malaysia and age-gender-ethnicity-specific data for Malaysia. The out-of-sample forecast error of log death rates, male-to-female death rate ratios and life expectancy at birth from each model are compared and examined across groups. The results show that, in terms of overall accuracy, the forecasts of both coherent models are consistently more accurate than those of the independent models for Australia and for Malaysia, but the relative performance differs by forecast horizon. Although the product-ratio functional model outperforms the Poisson common factor model for Australia, the Poisson common factor is more accurate for Malaysia. For the ethnic groups application, ethnic-coherence gives better results than gender-coherence. The results provide evidence that coherent models are preferable to independent models for forecasting sub-populations’ mortality.

  7. Entropy coherent and entropy convex measures of risk

    NARCIS (Netherlands)

    Laeven, R.J.A.; Stadje, M.

    2013-01-01

    We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. Entropy coherent and entropy convex measures of risk are special cases of φ-coherent and φ-convex measures of risk. Contrary to the classical use of coherent and convex

  8. Study protocol for the recreational stimulation for elders as a vehicle to resolve delirium superimposed on dementia (Reserve For DSD trial

    Directory of Open Access Journals (Sweden)

    Leslie Doug

    2011-05-01

    Full Text Available Abstract Background Delirium is a state of confusion characterized by an acute and fluctuating decline in cognitive functioning. Delirium is common and deadly in older adults with dementia, and is often referred to as delirium superimposed on dementia, or DSD. Interventions that treat DSD are not well-developed because the mechanisms involved in its etiology are not completely understood. We have developed a theory-based intervention for DSD that is derived from the literature on cognitive reserve and based on our prior interdisciplinary work on delirium, recreational activities, and cognitive stimulation in people with dementia. Our preliminary work indicate that use of simple, cognitively stimulating activities may help resolve delirium by helping to focus inattention, the primary neuropsychological deficit in delirium. Our primary aim in this trial is to test the efficacy of Recreational Stimulation for Elders as a Vehicle to resolve DSD (RESERVE- DSD. Methods/Design This randomized repeated measures clinical trial will involve participants being recruited and enrolled at the time of admission to post acute care. We will randomize 256 subjects to intervention (RESERVE-DSD or control (usual care. Intervention subjects will receive 30-minute sessions of tailored cognitively stimulating recreational activities for up to 30 days. We hypothesize that subjects who receive RESERVE-DSD will have: decreased severity and duration of delirium; greater gains in attention, orientation, memory, abstract thinking, and executive functioning; and greater gains in physical function compared to subjects with DSD who receive usual care. We will also evaluate potential moderators of intervention efficacy (lifetime of complex mental activities and APOE status. Our secondary aim is to describe the costs associated with RESERVE-DSD. Discussion Our theory-based intervention, which uses simple, inexpensive recreational activities for delivering cognitive stimulation

  9. Conical electromagnetic radiation flux concentrator

    Science.gov (United States)

    Miller, E. R.

    1972-01-01

    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  10. Physics of Magnetic Flux Ropes

    CERN Document Server

    Priest, E R; Lee, L C

    1990-01-01

    The American Geophysical Union Chapman Conference on the Physics of Magnetic Flux Ropes was held at the Hamilton Princess Hotel, Hamilton, Bermuda on March 27–31, 1989. Topics discussed ranged from solar flux ropes, such as photospheric flux tubes, coronal loops and prominences, to flux ropes in the solar wind, in planetary ionospheres, at the Earth's magnetopause, in the geomagnetic tail and deep in the Earth's magnetosphere. Papers presented at that conference form the nucleus of this book, but the book is more than just a proceedings of the conference. We have solicited articles from all interested in this topic. Thus, there is some material in the book not discussed at the conference. Even in the case of papers presented at the conference, there is generally a much more detailed and rigorous presentation than was possible in the time allowed by the oral and poster presentations.

  11. Notes on neutron flux measurement

    International Nuclear Information System (INIS)

    Alcala Ruiz, F.

    1984-01-01

    The main purpose of this work is to get an useful guide to carry out topical neutron flux measurements. Although the foil activation technique is used in the majority of the cases, other techniques, such as those based on fission chambers and self-powered neutron detectors, are also shown. Special interest is given to the description and application of corrections on the measurement of relative and absolute induced activities by several types of detectors (scintillators, G-M and gas proportional counters). The thermal arid epithermal neutron fluxes, as determined in this work, are conventional or effective (West cots fluxes), which are extensively used by the reactor experimentalists; however, we also give some expressions where they are related to the integrated neutron fluxes, which are used in neutron calculations. (Author) 16 refs

  12. Specification of ROP flux shape

    International Nuclear Information System (INIS)

    Min, Byung Joo; Gray, A.

    1997-06-01

    The CANDU 9 480/SEU core uses 0.9% SEU (Slightly Enriched Uranium) fuel. The use f SEU fuel enables the reactor to increase the radial power form factor from 0.865, which is typical in current natural uranium CANDU reactors, to 0.97 in the nominal CANDU 9 480/SEU core. The difference is a 12% increase in reactor power. An additional 5% increase can be achieved due to a reduced refuelling ripple. The channel power limits were also increased by 3% for a total reactor power increase of 20%. This report describes the calculation of neutron flux distributions in the CANDU 9 480/SEU core under conditions specified by the C and I engineers. The RFSP code was used to calculate of neutron flux shapes for ROP analysis. Detailed flux values at numerous potential detector sites were calculated for each flux shape. (author). 6 tabs., 70 figs., 4 refs

  13. Specification of ROP flux shape

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byung Joo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Gray, A [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1997-06-01

    The CANDU 9 480/SEU core uses 0.9% SEU (Slightly Enriched Uranium) fuel. The use f SEU fuel enables the reactor to increase the radial power form factor from 0.865, which is typical in current natural uranium CANDU reactors, to 0.97 in the nominal CANDU 9 480/SEU core. The difference is a 12% increase in reactor power. An additional 5% increase can be achieved due to a reduced refuelling ripple. The channel power limits were also increased by 3% for a total reactor power increase of 20%. This report describes the calculation of neutron flux distributions in the CANDU 9 480/SEU core under conditions specified by the C and I engineers. The RFSP code was used to calculate of neutron flux shapes for ROP analysis. Detailed flux values at numerous potential detector sites were calculated for each flux shape. (author). 6 tabs., 70 figs., 4 refs.

  14. High Flux Isotope Reactor (HFIR)

    Data.gov (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  15. Flux networks in metabolic graphs

    International Nuclear Information System (INIS)

    Warren, P B; Queiros, S M Duarte; Jones, J L

    2009-01-01

    A metabolic model can be represented as a bipartite graph comprising linked reaction and metabolite nodes. Here it is shown how a network of conserved fluxes can be assigned to the edges of such a graph by combining the reaction fluxes with a conserved metabolite property such as molecular weight. A similar flux network can be constructed by combining the primal and dual solutions to the linear programming problem that typically arises in constraint-based modelling. Such constructions may help with the visualization of flux distributions in complex metabolic networks. The analysis also explains the strong correlation observed between metabolite shadow prices (the dual linear programming variables) and conserved metabolite properties. The methods were applied to recent metabolic models for Escherichia coli, Saccharomyces cerevisiae and Methanosarcina barkeri. Detailed results are reported for E. coli; similar results were found for other organisms

  16. Boundary fluxes for nonlocal diffusion

    Science.gov (United States)

    Cortazar, Carmen; Elgueta, Manuel; Rossi, Julio D.; Wolanski, Noemi

    We study a nonlocal diffusion operator in a bounded smooth domain prescribing the flux through the boundary. This problem may be seen as a generalization of the usual Neumann problem for the heat equation. First, we prove existence, uniqueness and a comparison principle. Next, we study the behavior of solutions for some prescribed boundary data including blowing up ones. Finally, we look at a nonlinear flux boundary condition.

  17. Energy flux of hot atoms

    International Nuclear Information System (INIS)

    Wotzak, G.P.; Kostin, M.D.

    1976-01-01

    The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

  18. Flux tubes at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)

    2016-06-07

    The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

  19. P fluxes and exotic branes

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, Davide M. [Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); Riccioni, Fabio [INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); Risoli, Stefano [Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy)

    2016-12-21

    We consider the N=1 superpotential generated in type-II orientifold models by non-geometric fluxes. In particular, we focus on the family of P fluxes, that are related by T-duality transformations to the S-dual of the Q flux. We determine the general rule that transforms a given flux in this family under a single T-duality transformation. This rule allows to derive a complete expression for the superpotential for both the IIA and the IIB theory for the particular case of a T{sup 6}/[ℤ{sub 2}×ℤ{sub 2}] orientifold. We then consider how these fluxes modify the generalised Bianchi identities. In particular, we derive a fully consistent set of quadratic constraints coming from the NS-NS Bianchi identities. On the other hand, the P flux Bianchi identities induce tadpoles, and we determine a set of exotic branes that can be consistently included in order to cancel them. This is achieved by determining a universal transformation rule under T-duality satisfied by all the branes in string theory.

  20. P fluxes and exotic branes

    International Nuclear Information System (INIS)

    Lombardo, Davide M.; Riccioni, Fabio; Risoli, Stefano

    2016-01-01

    We consider the N=1 superpotential generated in type-II orientifold models by non-geometric fluxes. In particular, we focus on the family of P fluxes, that are related by T-duality transformations to the S-dual of the Q flux. We determine the general rule that transforms a given flux in this family under a single T-duality transformation. This rule allows to derive a complete expression for the superpotential for both the IIA and the IIB theory for the particular case of a T 6 /[ℤ 2 ×ℤ 2 ] orientifold. We then consider how these fluxes modify the generalised Bianchi identities. In particular, we derive a fully consistent set of quadratic constraints coming from the NS-NS Bianchi identities. On the other hand, the P flux Bianchi identities induce tadpoles, and we determine a set of exotic branes that can be consistently included in order to cancel them. This is achieved by determining a universal transformation rule under T-duality satisfied by all the branes in string theory.

  1. MULTILEVEL ISCHEMIA IN DISORGANIZATION OF THE RETINAL INNER LAYERS ON PROJECTION-RESOLVED OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

    Science.gov (United States)

    Onishi, Alex C; Ashraf, Mohammed; Soetikno, Brian T; Fawzi, Amani A

    2018-04-10

    To examine the relationship between ischemia and disorganization of the retinal inner layers (DRIL). Cross-sectional retrospective study of 20 patients (22 eyes) with diabetic retinopathy presenting to a tertiary academic referral center, who had DRIL on structural optical coherence tomography (OCT) using Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany) and OCT angiography with XR Avanti (Optovue Inc, Fremont, CA) on the same day. Optical coherence tomography angiography images were further processed to remove flow signal projection artifacts using a software algorithm adapted from recent studies. Retinal capillary perfusion in the superficial capillary plexuses, middle capillary plexuses, and deep capillary plexuses, as well as integrity of the photoreceptor lines on OCT was compared in areas with DRIL to control areas without DRIL in the same eye. Qualitative assessment of projection-resolved OCT angiography of eyes with DRIL on structural OCT demonstrated significant perfusion deficits compared with adjacent control areas (P < 0.001). Most lesions (85.7%) showed superimposed superficial capillary plexus and/or middle capillary plexus nonperfusion in addition to deep capillary plexus nonflow. Areas of DRIL were significantly associated with photoreceptor disruption (P = 0.035) compared with adjacent DRIL-free areas. We found that DRIL is associated with multilevel retinal capillary nonperfusion, suggesting an important role for ischemia in this OCT phenotype.

  2. Modeling the Solar Convective Dynamo and Emerging Flux

    Science.gov (United States)

    Fan, Y.

    2017-12-01

    Significant advances have been made in recent years in global-scale fully dynamic three-dimensional convective dynamo simulations of the solar/stellar convective envelopes to reproduce some of the basic features of the Sun's large-scale cyclic magnetic field. It is found that the presence of the dynamo-generated magnetic fields plays an important role for the maintenance of the solar differential rotation, without which the differential rotation tends to become anti-solar (with a faster rotating pole instead of the observed faster rotation at the equator). Convective dynamo simulations are also found to produce emergence of coherent super-equipartition toroidal flux bundles with a statistically significant mean tilt angle that is consistent with the mean tilt of solar active regions. The emerging flux bundles are sheared by the giant cell convection into a forward leaning loop shape with its leading side (in the direction of rotation) pushed closer to the strong downflow lanes. Such asymmetric emerging flux pattern may lead to the observed asymmetric properties of solar active regions.

  3. Low-frequency excess flux noise in superconducting devices

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, Sebastian; Ferring, Anna; Fleischmann, Andreas; Enss, Christian [Kirchhoff-Institute for Physics, Heidelberg University (Germany)

    2016-07-01

    Low-frequency noise is a rather universal phenomenon and appears in physical, chemical, biological or even economical systems. However, there is often very little known about the underlying processes leading to its occurrence. In particular, the origin of low-frequency excess flux noise in superconducting devices has been an unresolved puzzle for many decades. Its existence limits, for example, the coherence time of superconducting quantum bits or makes high-precision measurements of low-frequency signals using SQUIDs rather challenging. Recent experiments suggest that low-frequency excess flux noise in Josephson junction based devices might be caused by the random reversal of interacting spins in surface layer oxides and in the superconductor-substrate interface. Even if it turns out to be generally correct, the underlying physical processes, i.e. the origin of these spins, their physical nature as well as the interaction mechanisms, have not been resolved so far. In this contribution we discuss recent measurements of low-frequency SQUID noise which we performed to investigate the origin of low-frequency excess flux noise in superconducting devices. Within this context we give an overview of our measurement techniques and link our data with present theoretical models and literature data.

  4. Measurement of the penetration depth and coherence length of MgB2 in all directions using transmission electron microscopy

    DEFF Research Database (Denmark)

    Loudon, J. C.; Yazdi, Sadegh; Kasama, Takeshi

    2015-01-01

    We demonstrate that images of flux vortices in a superconductor taken with a transmission electron microscope can be used to measure the penetration depth and coherence length in all directions at the same temperature and magnetic field. This is particularly useful for MgB2, where these quantities...... vary with the applied magnetic field and values are difficult to obtain at low field or in the c direction. We obtained images of flux vortices from a MgB2 single crystal cut in the ac plane by focused ion beam milling and tilted to 45 degrees. with respect to the electron beam about...... the crystallographic a axis. A new method was developed to simulate these images that accounted for vortices with a nonzero core in a thin, anisotropic superconductor and a simplex algorithm was used to make a quantitative comparison between the images and simulations to measure the penetration depths and coherence...

  5. Ultra-broadband ptychography with self-consistent coherence estimation from a high harmonic source

    Science.gov (United States)

    Odstrčil, M.; Baksh, P.; Kim, H.; Boden, S. A.; Brocklesby, W. S.; Frey, J. G.

    2015-09-01

    With the aim of improving imaging using table-top extreme ultraviolet sources, we demonstrate coherent diffraction imaging (CDI) with relative bandwidth of 20%. The coherence properties of the illumination probe are identified using the same imaging setup. The presented methods allows for the use of fewer monochromating optics, obtaining higher flux at the sample and thus reach higher resolution or shorter exposure time. This is important in the case of ptychography when a large number of diffraction patterns need to be collected. Our microscopy setup was tested on a reconstruction of an extended sample to show the quality of the reconstruction. We show that high harmonic generation based EUV tabletop microscope can provide reconstruction of samples with a large field of view and high resolution without additional prior knowledge about the sample or illumination.

  6. Coherently combining data between detectors for all-sky semi-coherent continuous gravitational wave searches

    International Nuclear Information System (INIS)

    Goetz, E; Riles, K

    2016-01-01

    We present a method for coherently combining short data segments from gravitational-wave detectors to improve the sensitivity of semi-coherent searches for continuous gravitational waves. All-sky searches for continuous gravitational waves from unknown sources are computationally limited. The semi-coherent approach reduces the computational cost by dividing the entire observation timespan into short segments to be analyzed coherently, then combined together incoherently. Semi-coherent analyses that attempt to improve sensitivity by coherently combining data from multiple detectors face a computational challenge in accounting for uncertainties in signal parameters. In this article, we lay out a technique to meet this challenge using summed Fourier transform coefficients. Applying this technique to one all-sky search algorithm called TwoSpect, we confirm that the sensitivity of all-sky, semi-coherent searches can be improved by coherently combining the short data segments, e.g., by up to 42% over a single detector for an all-sky search. For misaligned detectors, however, this improvement requires careful attention when marginalizing over unknown polarization parameters. In addition, care must be taken in correcting for differential detector velocity due to the Earth’s rotation for high signal frequencies and widely separated detectors. (paper)

  7. Identification of individual coherent sets associated with flow trajectories using coherent structure coloring

    Science.gov (United States)

    Schlueter-Kuck, Kristy L.; Dabiri, John O.

    2017-09-01

    We present a method for identifying the coherent structures associated with individual Lagrangian flow trajectories even where only sparse particle trajectory data are available. The method, based on techniques in spectral graph theory, uses the Coherent Structure Coloring vector and associated eigenvectors to analyze the distance in higher-dimensional eigenspace between a selected reference trajectory and other tracer trajectories in the flow. By analyzing this distance metric in a hierarchical clustering, the coherent structure of which the reference particle is a member can be identified. This algorithm is proven successful in identifying coherent structures of varying complexities in canonical unsteady flows. Additionally, the method is able to assess the relative coherence of the associated structure in comparison to the surrounding flow. Although the method is demonstrated here in the context of fluid flow kinematics, the generality of the approach allows for its potential application to other unsupervised clustering problems in dynamical systems such as neuronal activity, gene expression, or social networks.

  8. Flux flow and flux dynamics in high-Tc superconductors

    International Nuclear Information System (INIS)

    Bennett, L.H.; Turchinskaya, M.; Swartzendruber, L.J.; Roitburd, A.; Lundy, D.; Ritter, J.; Kaiser, D.L.

    1991-01-01

    Because high temperature superconductors, including BYCO and BSSCO, are type 2 superconductors with relatively low H(sub c 1) values and high H(sub c 2) values, they will be in a critical state for many of their applications. In the critical state, with the applied field between H(sub c 1) and H(sub c 2), flux lines have penetrated the material and can form a flux lattice and can be pinned by structural defects, chemical inhomogeneities, and impurities. A detailed knowledge of how flux penetrates the material and its behavior under the influence of applied fields and current flow, and the effect of material processing on these properties, is required in order to apply, and to improve the properties of these superconductors. When the applied field is changed rapidly, the time dependence of flux change can be divided into three regions, an initial region which occurs very rapidly, a second region in which the magnetization has a 1n(t) behavior, and a saturation region at very long times. A critical field is defined for depinning, H(sub c,p) as that field at which the hysteresis loop changes from irreversible to reversible. As a function of temperature, it is found that H(sub c,p) is well described by a power law with an exponent between 1.5 and 2.5. The behavior of H(sub c,p) for various materials and its relationship to flux flow and flux dynamics are discussed

  9. Coherence resonance in low-density jets

    Science.gov (United States)

    Zhu, Yuanhang; Gupta, Vikrant; Li, Larry K. B.

    2017-11-01

    Coherence resonance is a phenomenon in which the response of a stable nonlinear system to noise exhibits a peak in coherence at an intermediate noise amplitude. We report the first experimental evidence of coherence resonance in a purely hydrodynamic system, a low-density jet whose variants can be found in many natural and engineering systems. This evidence comprises four parts: (i) the jet's response amplitude increases as the Reynolds number approaches the instability boundary under a constant noise amplitude; (ii) as the noise amplitude increases, the amplitude distribution of the jet response first becomes unimodal, then bimodal, and finally unimodal again; (iii) a distinct peak emerges in the coherence factor at an intermediate noise amplitude; and (iv) for a subcritical Hopf bifurcation, the decay rate of the autocorrelation function exhibits a maximum at an intermediate noise amplitude, but for a supercritical Hopf bifurcation, the decay rate decreases monotonically with increasing noise amplitude. It is clear that coherence resonance can provide valuable information about a system's nonlinearity even in the unconditionally stable regime, opening up new possibilities for its use in system identification and flow control. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

  10. Mismatch removal via coherent spatial relations

    Science.gov (United States)

    Chen, Jun; Ma, Jiayi; Yang, Changcai; Tian, Jinwen

    2014-07-01

    We propose a method for removing mismatches from the given putative point correspondences in image pairs based on "coherent spatial relations." Under the Bayesian framework, we formulate our approach as a maximum likelihood problem and solve a coherent spatial relation between the putative point correspondences using an expectation-maximization (EM) algorithm. Our approach associates each point correspondence with a latent variable indicating it as being either an inlier or an outlier, and alternatively estimates the inlier set and recovers the coherent spatial relation. It can handle not only the case of image pairs with rigid motions but also the case of image pairs with nonrigid motions. To parameterize the coherent spatial relation, we choose two-view geometry and thin-plate spline as models for rigid and nonrigid cases, respectively. The mismatches could be successfully removed via the coherent spatial relations after the EM algorithm converges. The quantitative results on various experimental data demonstrate that our method outperforms many state-of-the-art methods, it is not affected by low initial correct match percentages, and is robust to most geometric transformations including a large viewing angle, image rotation, and affine transformation.

  11. Coherence techniques at extreme ultraviolet wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chang [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    The renaissance of Extreme Ultraviolet (EUV) and soft x-ray (SXR) optics in recent years is mainly driven by the desire of printing and observing ever smaller features, as in lithography and microscopy. This attribute is complemented by the unique opportunity for element specific identification presented by the large number of atomic resonances, essentially for all materials in this range of photon energies. Together, these have driven the need for new short-wavelength radiation sources (e.g. third generation synchrotron radiation facilities), and novel optical components, that in turn permit new research in areas that have not yet been fully explored. This dissertation is directed towards advancing this new field by contributing to the characterization of spatial coherence properties of undulator radiation and, for the first time, introducing Fourier optical elements to this short-wavelength spectral region. The first experiment in this dissertation uses the Thompson-Wolf two-pinhole method to characterize the spatial coherence properties of the undulator radiation at Beamline 12 of the Advanced Light Source. High spatial coherence EUV radiation is demonstrated with appropriate spatial filtering. The effects of small vertical source size and beamline apertures are observed. The difference in the measured horizontal and vertical coherence profile evokes further theoretical studies on coherence propagation of an EUV undulator beamline. A numerical simulation based on the Huygens-Fresnel principle is performed.

  12. Coherence characteristics of light-emitting diodes

    International Nuclear Information System (INIS)

    Mehta, Dalip Singh; Saxena, Kanchan; Dubey, Satish Kumar; Shakher, Chandra

    2010-01-01

    We report the measurement of coherence characteristics of light-emitting diodes (LEDs). Experiments were performed using red and green color LEDs directly illuminating the Young's double slit kept in the far-zone. Fourier transform fringe analysis technique was used for the measurement of the visibility of interference fringes from which the modulus of degree of spectral coherence was determined. Low degree of spectral coherence, typically 0.4 for red and 0.2 for green LED with double-slit separation of 400 μm was observed. A variable slit was then kept in front of the LEDs and the double slit was illuminated with the light coming out of the slit. Experiments were performed with various slit sizes and the visibility of the interference fringes was observed. It was found that visibility of the interference fringes changes drastically in presence of variable slit kept in front of LEDs and a high degree of spectral coherence, typically 0.85 for red and 0.8 for green LED with double-slit separation of 400 μm and rectangular slit opening of 500 μm was observed. The experimental results are compared with the theoretical counterparts. Coherence lengths of both the LEDs were also determined and it was obtained 5.8±2 and 24±4 μm for green and red LEDs, respectively.

  13. Thermality of the Hawking flux

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Matt [School of Mathematics, Statistics, and Operations Research,Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand)

    2015-07-03

    Is the Hawking flux “thermal”? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word “thermal”. The original 1850’s notions of thermality — based on classical thermodynamic reasoning applied to idealized “black bodies” or “lamp black surfaces” — when supplemented by specific basic quantum ideas from the early 1900’s, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but without any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lump of coal), is only approximately Planck-shaped over an explicitly bounded range of frequencies. Standard physics (phase space and adiabaticity effects) explicitly bound the frequency range over which the Hawking flux is approximately Planck-shaped from both above and below — the Hawking flux is certainly not exactly Planckian, and there is no compelling physics reason to assume the Hawking photons are uncorrelated.

  14. Thermality of the Hawking flux

    International Nuclear Information System (INIS)

    Visser, Matt

    2015-01-01

    Is the Hawking flux “thermal”? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word “thermal”. The original 1850’s notions of thermality — based on classical thermodynamic reasoning applied to idealized “black bodies” or “lamp black surfaces” — when supplemented by specific basic quantum ideas from the early 1900’s, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but without any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lump of coal), is only approximately Planck-shaped over an explicitly bounded range of frequencies. Standard physics (phase space and adiabaticity effects) explicitly bound the frequency range over which the Hawking flux is approximately Planck-shaped from both above and below — the Hawking flux is certainly not exactly Planckian, and there is no compelling physics reason to assume the Hawking photons are uncorrelated.

  15. Physics of magnetic flux tubes

    CERN Document Server

    Ryutova, Margarita

    2015-01-01

    This book is the first account of the physics of magnetic flux tubes from their fundamental properties to collective phenomena in an ensembles of flux tubes. The physics of magnetic flux tubes is absolutely vital for understanding fundamental physical processes in the solar atmosphere shaped and governed by magnetic fields. High-resolution and high cadence observations from recent space and  ground-based instruments taken simultaneously at different heights and temperatures not only show the ubiquity of filamentary structure formation but also allow to study how various events are interconnected by system of magnetic flux tubes. The book covers both theory and observations. Theoretical models presented in analytical and phenomenological forms are tailored for practical applications. These are welded with state-of-the-art observations from early decisive ones to the most recent data that open a new phase-space for exploring the Sun and sun-like stars. Concept of magnetic flux tubes is central to various magn...

  16. Field Dependent Coherence Length in the Superclean, High-κ Superconductor CeCoIn5

    International Nuclear Information System (INIS)

    DeBeer-Schmitt, L.; Eskildsen, M. R.; Dewhurst, C. D.; Hoogenboom, B. W.; Petrovic, C.

    2006-01-01

    Using small-angle neutron scattering, we have studied the flux-line lattice (FLL) in the superclean, high-κ superconductor CeCoIn 5 . The FLL undergoes a first-order symmetry and reorientation transition at ∼0.55 T at 50 mK. In addition, the FLL form factor in this material is found to be independent of the applied magnetic field, in striking contrast to the exponential decrease usually observed in superconductors. This result is consistent with a strongly field-dependent coherence length, proportional to the vortex separation

  17. Coherent vector-meson photoproduction with nuclear breakup in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Baltz, Anthony J.; Klein, Spencer R.; Nystrand, Joakim

    2002-01-01

    Relativistic heavy ions are copious sources of virtual photons. The large photon flux gives rise to a substantial photonuclear interaction probability at impact parameters where no hadronic interactions can occur. Multiple photonuclear interactions in a single collision are possible. In this Letter, we use mutual Coulomb excitation of both nuclei as a tag for moderate-impact-parameter collisions. We calculate the cross section for coherent vector-meson production accompanied by mutual excitation and show that the median impact parameter is much smaller than for untagged production. The vector-meson rapidity and transverse-momentum distribution are very different from untagged exclusive vector-meson production

  18. Design of a dedicated beamline for THz coherent synchrotron radiation at UVSOR-III

    International Nuclear Information System (INIS)

    Kimura, Shin-ichi; Nakamura, Eiken; Imura, Keiichiro; Katoh, Masahiro; Hosaka, Masahito; Takahashi, Toshiharu

    2012-01-01

    We report the design of a THz beamline for coherent synchrotron radiation (CSR) at the UVSOR-III very-low-emittance synchrotron radiation light source. The emitted THz-CSR is collected by a three-dimensional 'magic mirror', which is a perfect collecting mirror for bending-magnet radiation with an acceptance angle of 288 mrad (H) × 80 mrad (V). A quasi-monochromatic THz-CSR with an average flux of 104 μW/0.1 % b.w. and a peak power of 120 nJ/pulse/0.1 % b.w. is expected at the beamline.

  19. Anomalous property of coherent bremsstrahlung linear polarization of relativistic electrons in a crystal

    International Nuclear Information System (INIS)

    Lapko, V.P.; Nasonov, N.N.; Truten', V.I.

    1993-01-01

    Polarization and spectral-and-angular properties of γ-radiation of the relativistic electron flux moving in a crystal under uncorrelated collisions with crystal atomic chains, are studied theoretically. Direction of linear polarization of radiation is shown to vary with energy of emitted photon. Reasons of occurrence of this effect are discussed. The results of numerical calculations demonstrating the possibility to form an intensive source of polarized γ-quanta on the basis of coherent radiation of relativistic electrons during low-angular scattering at crystal atom chains, are given

  20. Electron flux during pericyclic reactions in the tunneling limit: Quantum simulation for cyclooctatetraene

    International Nuclear Information System (INIS)

    Hege, Hans-Christian; Manz, Joern; Marquardt, Falko; Paulus, Beate; Schild, Axel

    2010-01-01

    Graphical abstract: In the limit of coherent tunneling, double bond shifting (DBS) of cyclooctatetraene from a reactant (R) to a product (P) is associated with pericyclic electron fluxes from double to single bonds, corresponding to a pincer-motion-type set of arrows in the Lewis structures, each representing a transfer of 0.19 electrons. - Abstract: Pericyclic rearrangement of cyclooctatetraene proceeds from equivalent sets of two reactants to two products. In the ideal limit of coherent tunneling, these reactants and products may tunnel to each other by ring inversions and by double bond shifting (DBS). We derive simple cosinusoidal or sinusoidal time evolutions of the bond-to-bond electron fluxes and yields during DBS, for the tunneling scenario. These overall yields and fluxes may be decomposed into various contributions for electrons in so called pericyclic, other valence, and core orbitals. Pericyclic orbitals are defined as the subset of valence orbitals which describe the changes of Lewis structures during the pericyclic reaction. The quantum dynamical results are compared with the traditional scheme of fluxes of electrons in pericyclic orbitals, as provided by arrows in Lewis structures.

  1. Flux driven turbulence in tokamaks

    International Nuclear Information System (INIS)

    Garbet, X.; Ghendrih, P.; Ottaviani, M.; Sarazin, Y.; Beyer, P.; Benkadda, S.; Waltz, R.E.

    1999-01-01

    This work deals with tokamak plasma turbulence in the case where fluxes are fixed and profiles are allowed to fluctuate. These systems are intermittent. In particular, radially propagating fronts, are usually observed over a broad range of time and spatial scales. The existence of these fronts provide a way to understand the fast transport events sometimes observed in tokamaks. It is also shown that the confinement scaling law can still be of the gyroBohm type in spite of these large scale transport events. Some departure from the gyroBohm prediction is observed at low flux, i.e. when the gradients are close to the instability threshold. Finally, it is found that the diffusivity is not the same for a turbulence calculated at fixed flux than at fixed temperature gradient, with the same time averaged profile. (author)

  2. Methane flux from boreal peatlands

    International Nuclear Information System (INIS)

    Crill, P.; Bartlett, K.; Roulet, N.

    1992-01-01

    The peatlands in the boreal zone (roughly 45 deg - 60 degN) store a significant reservoir of carbon, much of which is potentially available for exchange with the atmosphere. The anaerobic conditions that cause these soils to accumulate carbon also makes wet, boreal peatlands significant sources of methane to the global troposphere. It is estimated that boreal wetlands contribute approximately 19.5 Tg methane per year. The data available on the magnitude of boreal methane emissions have rapidly accumulated in the past twenty years. This paper offers a short review of the flux measured (with range roughly 1 - 2000 mg methane/m2d), considers environmental controls of the flux and briefly discusses how climate change might affect future fluxes

  3. Wide range neutron flux monitor

    International Nuclear Information System (INIS)

    Endo, Yorimasa; Fukushima, Toshiki.

    1983-01-01

    Purpose: To provide a wide range neutron-flux monitor adapted such that the flux monitoring function and alarming function can automatically by shifted from pulse counting system to cambel method system. Constitution: A wide range neutron-flux monitor comprises (la) pulse counting system and (lb) cambel-method system for inputting detection signals from neutron detectors and separating them into signals for the pulse measuring system and the cambel measuring system, (2) overlap detection and calculation circuit for detecting the existence of the overlap of two output signals from the (la) and (lb) systems, and (3) trip circuit for judging the abnormal state of neutron detectors upon input of the detection signals. (Seki, T.)

  4. High heat flux facility GLADIS

    International Nuclear Information System (INIS)

    Greuner, H.; Boeswirth, B.; Boscary, J.; McNeely, P.

    2007-01-01

    The new ion beam facility GLADIS started the operation at IPP Garching. The facility is equipped with two individual 1.1 MW power ion sources for testing actively cooled plasma facing components under high heat fluxes. Each ion source generates heat loads between 3 and 55 MW/m 2 with a beam diameter of 70 mm at the target position. These parameters allow effective testing from probes to large components up to 2 m length. The high heat flux allows the target to be installed inclined to the beam and thus increases the heated surface length up to 200 mm for a heat flux of 15 MW/m 2 in the standard operating regime. Thus the facility has the potential capability for testing of full scale ITER divertor targets. Heat load tests on the WENDELSTEIN 7-X pre-series divertor targets have been successfully started. These tests will validate the design and manufacturing for the production of 950 elements

  5. Heat flux driven ion turbulence

    International Nuclear Information System (INIS)

    Garbet, X.

    1998-01-01

    This work is an analysis of an ion turbulence in a tokamak in the case where the thermal flux is fixed and the temperature profile is allowed to fluctuate. The system exhibits some features of Self-Organized Critical systems. In particular, avalanches are observed. Also the frequency spectrum of the thermal flux exhibits a structure similar to the one of a sand pile automaton, including a 1/f behavior. However, the time average temperature profile is found to be supercritical, i.e. the temperature gradient stays above the critical value. Moreover, the heat diffusivity is lower for a turbulence calculated at fixed flux than a fixed temperature gradient, with the same time average temperature. This behavior is attributed to a stabilizing effect of avalanches. (author)

  6. Ideal flux field dielectric concentrators.

    Science.gov (United States)

    García-Botella, Angel

    2011-10-01

    The concept of the vector flux field was first introduced as a photometrical theory and later developed in the field of nonimaging optics; it has provided new perspectives in the design of concentrators, overcoming standard ray tracing techniques. The flux field method has shown that reflective concentrators with the geometry of the field lines achieve the theoretical limit of concentration. In this paper we study the role of surfaces orthogonal to the field vector J. For rotationally symmetric systems J is orthogonal to its curl, and then a family of surfaces orthogonal to the lines of J exists, which can be called the family of surfaces of constant pseudopotential. Using the concept of the flux tube, it is possible to demonstrate that refractive concentrators with the shape of these pseudopotential surfaces achieve the theoretical limit of concentration.

  7. Flux flow and flux creep in thick films of YBCO. [Y-Ba-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Rickets, J.; Vinen, W.F.; Abell, J.S.; Shields, T.C. (Superconductivity Research Group, Univ. of Birmingham (United Kingdom))

    1991-12-01

    The results are described of new experiments designed to study flux creep and flux flow along a single flux percolation path in thick films of YBCO. The flux flow regime is studied by a four-point resistive technique using pulsed currents, and the flux creep regime by observing the rate at which flux enters a superconducting loop in parallel with the resistance that is associated with the flux percolation path. (orig.).

  8. Reconnection of a Kinking Flux Rope Triggering the Ejection of a Microwave and Hard X-Ray Source. 2. Numerical Modeling

    Science.gov (United States)

    2010-07-14

    apex. The external field is thus mainly poloidal, with the ratio between toroidal and poloidal components at the flux rope apex being Bet/ Bep = 0.075...eruption involved a kink-unstable flux rope that had a high twist of Φ & 6π. This yields a coherent framework to understand the inverse gamma shape...leading to these results has received funding from the European Commission’s Seventh Framework Programme (FP7/2007-2013) under the grant agreement n 218816

  9. Coherence method of identifying signal noise model

    International Nuclear Information System (INIS)

    Vavrin, J.

    1981-01-01

    The noise analysis method is discussed in identifying perturbance models and their parameters by a stochastic analysis of the noise model of variables measured on a reactor. The analysis of correlations is made in the frequency region using coherence analysis methods. In identifying an actual specific perturbance, its model should be determined and recognized in a compound model of the perturbance system using the results of observation. The determination of the optimum estimate of the perturbance system model is based on estimates of related spectral densities which are determined from the spectral density matrix of the measured variables. Partial and multiple coherence, partial transfers, the power spectral densities of the input and output variables of the noise model are determined from the related spectral densities. The possibilities of applying the coherence identification methods were tested on a simple case of a simulated stochastic system. Good agreement was found of the initial analytic frequency filters and the transfers identified. (B.S.)

  10. Color coherence in W + jet events

    International Nuclear Information System (INIS)

    Abbott, B.

    1997-11-01

    We report on preliminary studies of color coherence effects in p anti p collisions, based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron collider, at a center of mass energy √s = 1.8 TeV. Color interference effects are studied by examining particle distribution patterns in W + Jet events. The data are compared to Monte Carlo simulations with different color coherence implementations and to a recent analytic Modified-Leading-Log perturbative calculation based on the Local Parton-Hadron Duality hypothesis. Soft particle radiation is enhanced in the event plane relative to the transverse plane, in agreement with calculations in which the effects of color coherence are fully included

  11. Store-operate-coherence-on-value

    Science.gov (United States)

    Chen, Dong; Heidelberger, Philip; Kumar, Sameer; Ohmacht, Martin; Steinmacher-Burow, Burkhard

    2014-11-18

    A system, method and computer program product for performing various store-operate instructions in a parallel computing environment that includes a plurality of processors and at least one cache memory device. A queue in the system receives, from a processor, a store-operate instruction that specifies under which condition a cache coherence operation is to be invoked. A hardware unit in the system runs the received store-operate instruction. The hardware unit evaluates whether a result of the running the received store-operate instruction satisfies the condition. The hardware unit invokes a cache coherence operation on a cache memory address associated with the received store-operate instruction if the result satisfies the condition. Otherwise, the hardware unit does not invoke the cache coherence operation on the cache memory device.

  12. Coherent states for quantum compact groups

    International Nuclear Information System (INIS)

    Jurco, B.; Stovicek, P.; CTU, Prague

    1996-01-01

    Coherent states are introduced and their properties are discussed for simple quantum compact groups A l , B l , C l and D l . The multiplicative form of the canonical element for the quantum double is used to introduce the holomorphic coordinates on a general quantum dressing orbit. The coherent state is interpreted as a holomorphic function on this orbit with values in the carrier Hilbert space of an irreducible representation of the corresponding quantized enveloping algebra. Using Gauss decomposition, the commutation relations for the holomorphic coordinates on the dressing orbit are derived explicitly and given in a compact R-matrix formulation (generalizing this way the q-deformed Grassmann and flag manifolds). The antiholomorphic realization of the irreducible representations of a compact quantum group (the analogue of the Borel-Weil construction) is described using the concept of coherent state. The relation between representation theory and non-commutative differential geometry is suggested. (orig.)

  13. Coherent states for quantum compact groups

    Energy Technology Data Exchange (ETDEWEB)

    Jurco, B. [European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.; Stovicek, P. [Ceske Vysoke Uceni Technicke, Prague (Czech Republic). Dept. of Mathematics]|[CTU, Prague (Czech Republic). Doppler Inst.

    1996-12-01

    Coherent states are introduced and their properties are discussed for simple quantum compact groups A{sub l}, B{sub l}, C{sub l} and D{sub l}. The multiplicative form of the canonical element for the quantum double is used to introduce the holomorphic coordinates on a general quantum dressing orbit. The coherent state is interpreted as a holomorphic function on this orbit with values in the carrier Hilbert space of an irreducible representation of the corresponding quantized enveloping algebra. Using Gauss decomposition, the commutation relations for the holomorphic coordinates on the dressing orbit are derived explicitly and given in a compact R-matrix formulation (generalizing this way the q-deformed Grassmann and flag manifolds). The antiholomorphic realization of the irreducible representations of a compact quantum group (the analogue of the Borel-Weil construction) is described using the concept of coherent state. The relation between representation theory and non-commutative differential geometry is suggested. (orig.)

  14. Coherent states for quantum compact groups

    CERN Document Server

    Jurco, B

    1996-01-01

    Coherent states are introduced and their properties are discussed for all simple quantum compact groups. The multiplicative form of the canonical element for the quantum double is used to introduce the holomorphic coordinates on a general quantum dressing orbit and interpret the coherent state as a holomorphic function on this orbit with values in the carrier Hilbert space of an irreducible representation of the corresponding quantized enveloping algebra. Using Gauss decomposition, the commutation relations for the holomorphic coordinates on the dressing orbit are derived explicitly and given in a compact R--matrix formulation (generalizing this way the q--deformed Grassmann and flag manifolds). The antiholomorphic realization of the irreducible representations of a compact quantum group (the analogue of the Borel--Weil construction) are described using the concept of coherent state. The relation between representation theory and non--commutative differential geometry is suggested.}

  15. Phase coherence induced by correlated disorder.

    Science.gov (United States)

    Hong, Hyunsuk; O'Keeffe, Kevin P; Strogatz, Steven H

    2016-02-01

    We consider a mean-field model of coupled phase oscillators with quenched disorder in the coupling strengths and natural frequencies. When these two kinds of disorder are uncorrelated (and when the positive and negative couplings are equal in number and strength), it is known that phase coherence cannot occur and synchronization is absent. Here we explore the effects of correlating the disorder. Specifically, we assume that any given oscillator either attracts or repels all the others, and that the sign of the interaction is deterministically correlated with the given oscillator's natural frequency. For symmetrically correlated disorder with zero mean, we find that the system spontaneously synchronizes, once the width of the frequency distribution falls below a critical value. For asymmetrically correlated disorder, the model displays coherent traveling waves: the complex order parameter becomes nonzero and rotates with constant frequency different from the system's mean natural frequency. Thus, in both cases, correlated disorder can trigger phase coherence.

  16. Coherent active polarization control without loss

    Science.gov (United States)

    Ye, Yuqian; Hay, Darrick; Shi, Zhimin

    2017-11-01

    We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.

  17. Coherent active polarization control without loss

    Directory of Open Access Journals (Sweden)

    Yuqian Ye

    2017-11-01

    Full Text Available We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.

  18. Affine coherent states and Toeplitz operators

    Science.gov (United States)

    Hutníková, Mária; Hutník, Ondrej

    2012-06-01

    We study a parameterized family of Toeplitz operators in the context of affine coherent states based on the Calderón reproducing formula (= resolution of unity on L_2( {R})) and the specific admissible wavelets (= affine coherent states in L_2( {R})) related to Laguerre functions. Symbols of such Calderón-Toeplitz operators as individual coordinates of the affine group (= upper half-plane with the hyperbolic geometry) are considered. In this case, a certain class of pseudo-differential operators, their properties and their operator algebras are investigated. As a result of this study, the Fredholm symbol algebras of the Calderón-Toeplitz operator algebras for these particular cases of symbols are described. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’.

  19. Long coherence times for edge spins

    Science.gov (United States)

    Kemp, Jack; Yao, Norman Y.; Laumann, Christopher R.; Fendley, Paul

    2017-06-01

    We show that in certain one-dimensional spin chains with open boundary conditions, the edge spins retain memory of their initial state for very long times, even at infinite temperature. The long coherence times do not require disorder, only an ordered phase. In the integrable Ising and XYZ chains, the presence of a strong zero mode means the coherence time is infinite. When Ising is perturbed by interactions breaking the integrability, the coherence time remains exponentially long in the perturbing couplings. We show that this is a consequence of an edge ‘almost’ strong zero mode that almost commutes with the Hamiltonian. We compute this operator explicitly, allowing us to estimate accurately the plateau value of edge spin autocorrelator.

  20. von Neumann's hypothesis concerning coherent states

    International Nuclear Information System (INIS)

    Zak, J

    2003-01-01

    An orthonormal basis of modified coherent states is constructed. Each member of the basis is an infinite sum of coherent states on a von Neumann lattice. A single state is assigned to each unit cell of area h (Planck constant) in the phase plane. The uncertainties of the coordinate x and the square of the momentum p 2 for these states are shown to be similar to those for the usual coherent states. Expansions in the newly established set are discussed and it is shown that any function in the kq-representation can be written as a sum of two fixed kq-functions. Approximate commuting operators for x and p 2 are defined on a lattice in phase plane according to von Neumann's prescription. (leeter to the editor)

  1. Controlling Casimir force via coherent driving field

    Science.gov (United States)

    Ahmad, Rashid; Abbas, Muqaddar; Ahmad, Iftikhar; Qamar, Sajid

    2016-04-01

    A four level atom-field configuration is used to investigate the coherent control of Casimir force between two identical plates made up of chiral atomic media and separated by vacuum of width d. The electromagnetic chirality-induced negative refraction is obtained via atomic coherence. The behavior of Casimir force is investigated using Casimir-Lifshitz formula. It is noticed that Casimir force can be switched from repulsive to attractive and vice versa via coherent control of the driving field. This switching feature provides new possibilities of using the repulsive Casimir force in the development of new emerging technologies, such as, micro-electro-mechanical and nano-electro-mechanical systems, i.e., MEMS and NEMS, respectively.

  2. Growth of transverse coherence in SASE FELs

    International Nuclear Information System (INIS)

    Kumar, Vinit; Krishnagopal, Srinivas

    2000-01-01

    We introduce the correlation function between the electric field at two different points in the transverse plane as a parameter to quantify the degree of transverse coherence. We also propose a more realistic model for the initialization of the radiation in computer codes used to study SASE FELs. We make these modifications in the code TDA and use it to study the growth of transverse coherence as a function of electron beam size, beam current and transverse emittance. Our results show explicitly that the onset of full transverse coherence in SASE takes place much before the power saturates. With the more realistic model the onset of the exponential growth regime is delayed, and to get a given power from the FEL one needs a longer undulator than would be predicted by the original TDA code

  3. Coherence in the Danish Healthcare System

    DEFF Research Database (Denmark)

    Frederiksen, Jesper; Olivares Bøgeskov, Benjamin Miguel

    2017-01-01

    In this article, we investigate ‘coherence in healthcare’ as a strategy of welfare policy. We conduct our investigation within the theoretical and methodological framework of Scandinavian praxeology, and we construct our empirical data from Danish administrative documents. The tools and terms...... of this tradition are used to generate data from discourse as representations of institutional logics. The aim is to uncover how coherence in healthcare emerges as different strategies in healthcare governance in relation to different institutions seen as positions. Hence, our findings suggest that, although...... the stated aim in policy is to improve coherence in healthcare for the benefit of the patients, various ambiguities within the institutions producing policy tend to maintain a certain order rather than introducing changes. Furthermore, we discuss how this section of the welfare state, examined in relation...

  4. Coherent Bichromatic Force Deflection of Molecules

    Science.gov (United States)

    Kozyryev, Ivan; Baum, Louis; Aldridge, Leland; Yu, Phelan; Eyler, Edward E.; Doyle, John M.

    2018-02-01

    We demonstrate the effect of the coherent optical bichromatic force on a molecule, the polar free radical strontium monohydroxide (SrOH). A dual-frequency retroreflected laser beam addressing the X˜2Σ+↔A˜2Π1 /2 electronic transition coherently imparts momentum onto a cryogenic beam of SrOH. This directional photon exchange creates a bichromatic force that transversely deflects the molecules. By adjusting the relative phase between the forward and counterpropagating laser beams we reverse the direction of the applied force. A momentum transfer of 70 ℏk is achieved with minimal loss of molecules to dark states. Modeling of the bichromatic force is performed via direct numerical solution of the time-dependent density matrix and is compared with experimental observations. Our results open the door to further coherent manipulation of molecular motion, including the efficient optical deceleration of diatomic and polyatomic molecules with complex level structures.

  5. Coherent Synchrotron Radiation: Theory and Simulations

    International Nuclear Information System (INIS)

    Novokhatski, Alexander

    2012-01-01

    The physics of coherent synchrotron radiation (CSR) emitted by ultra-relativistic electron bunches, known since the last century, has become increasingly important with the development of high peak current free electron lasers and shorter bunch lengths in storage rings. Coherent radiation can be described as a low frequency part of the familiar synchrotron radiation in bending magnets. As this part is independent of the electron energy, the fields of different electrons of a short bunch can be in phase and the total power of the radiation will be quadratic with the number of electrons. Naturally the frequency spectrum of the longitudinal electron distribution in a bunch is of the same importance as the overall electron bunch length. The interest in the utilization of high power radiation from the terahertz and far infrared region in the field of chemical, physical and biological processes has led synchrotron radiation facilities to pay more attention to the production of coherent radiation. Several laboratories have proposed the construction of a facility wholly dedicated to terahertz production using the coherent radiation in bending magnets initiated by the longitudinal instabilities in the ring. Existing synchrotron radiation facilities also consider such a possibility among their future plans. There is a beautiful introduction to CSR in the 'ICFA Beam Dynamics Newsletter' N 35 (Editor C. Biscari). In this paper we recall the basic properties of CSR from the theory and what new effects, we can get from the precise simulations of the coherent radiation using numerical solutions of Maxwell's equations. In particular, transverse variation of the particle energy loss in a bunch, discovered in these simulations, explains the slice emittance growth in bending magnets of the bunch compressors and transverse de-coherence in undulators. CSR may play same the role as the effect of quantum fluctuations of synchrotron radiation in damping rings. It can limit the minimum

  6. The flux database concerted action

    International Nuclear Information System (INIS)

    Mitchell, N.G.; Donnelly, C.E.

    1999-01-01

    This paper summarizes the background to the UIR action on the development of a flux database for radionuclide transfer in soil-plant systems. The action is discussed in terms of the objectives, the deliverables and the progress achieved so far by the flux database working group. The paper describes the background to the current initiative and outlines specific features of the database and supporting documentation. Particular emphasis is placed on the proforma used for data entry, on the database help file and on the approach adopted to indicate data quality. Refs. 3 (author)

  7. Methods and applications in high flux neutron imaging

    International Nuclear Information System (INIS)

    Ballhausen, H.

    2007-01-01

    This treatise develops new methods for high flux neutron radiography and high flux neutron tomography and describes some of their applications in actual experiments. Instead of single images, time series can be acquired with short exposure times due to the available high intensity. To best use the increased amount of information, new estimators are proposed, which extract accurate results from the recorded ensembles, even if the individual piece of data is very noisy and in addition severely affected by systematic errors such as an influence of gamma background radiation. The spatial resolution of neutron radiographies, usually limited by beam divergence and inherent resolution of the scintillator, can be significantly increased by scanning the sample with a pinhole-micro-collimator. This technique circumvents any limitations in present detector design and, due to the available high intensity, could be successfully tested. Imaging with scattered neutrons as opposed to conventional total attenuation based imaging determines separately the absorption and scattering cross sections within the sample. For the first time even coherent angle dependent scattering could be visualized space-resolved. New applications of high flux neutron imaging are presented, such as materials engineering experiments on innovative metal joints, time-resolved tomography on multilayer stacks of fuel cells under operation, and others. A new implementation of an algorithm for the algebraic reconstruction of tomography data executes even in case of missing information, such as limited angle tomography, and returns quantitative reconstructions. The setup of the world-leading high flux radiography and tomography facility at the Institut Laue-Langevin is presented. A comprehensive appendix covers the physical and technical foundations of neutron imaging. (orig.)

  8. Coherent diffractive imaging methods for semiconductor manufacturing

    Science.gov (United States)

    Helfenstein, Patrick; Mochi, Iacopo; Rajeev, Rajendran; Fernandez, Sara; Ekinci, Yasin

    2017-12-01

    The paradigm shift of the semiconductor industry moving from deep ultraviolet to extreme ultraviolet lithography (EUVL) brought about new challenges in the fabrication of illumination and projection optics, which constitute one of the core sources of cost of ownership for many of the metrology tools needed in the lithography process. For this reason, lensless imaging techniques based on coherent diffractive imaging started to raise interest in the EUVL community. This paper presents an overview of currently on-going research endeavors that use a number of methods based on lensless imaging with coherent light.

  9. Coherence protection in coupled quantum systems

    Science.gov (United States)

    Cammack, H. M.; Kirton, P.; Stace, T. M.; Eastham, P. R.; Keeling, J.; Lovett, B. W.

    2018-02-01

    The interaction of a quantum system with its environment causes decoherence, setting a fundamental limit on its suitability for quantum information processing. However, we show that if the system consists of coupled parts with different internal energy scales then the interaction of one part with a thermal bath need not lead to loss of coherence from the other. Remarkably, we find that the protected part can remain coherent for longer when the coupling to the bath becomes stronger or the temperature is raised. Our theory will enable the design of decoherence-resistant hybrid quantum computers.

  10. Audio frequency in vivo optical coherence elastography

    Science.gov (United States)

    Adie, Steven G.; Kennedy, Brendan F.; Armstrong, Julian J.; Alexandrov, Sergey A.; Sampson, David D.

    2009-05-01

    We present a new approach to optical coherence elastography (OCE), which probes the local elastic properties of tissue by using optical coherence tomography to measure the effect of an applied stimulus in the audio frequency range. We describe the approach, based on analysis of the Bessel frequency spectrum of the interferometric signal detected from scatterers undergoing periodic motion in response to an applied stimulus. We present quantitative results of sub-micron excitation at 820 Hz in a layered phantom and the first such measurements in human skin in vivo.

  11. Audio frequency in vivo optical coherence elastography

    International Nuclear Information System (INIS)

    Adie, Steven G; Kennedy, Brendan F; Armstrong, Julian J; Alexandrov, Sergey A; Sampson, David D

    2009-01-01

    We present a new approach to optical coherence elastography (OCE), which probes the local elastic properties of tissue by using optical coherence tomography to measure the effect of an applied stimulus in the audio frequency range. We describe the approach, based on analysis of the Bessel frequency spectrum of the interferometric signal detected from scatterers undergoing periodic motion in response to an applied stimulus. We present quantitative results of sub-micron excitation at 820 Hz in a layered phantom and the first such measurements in human skin in vivo.

  12. Topological Coherent Modes in Trapped Bose Gas

    International Nuclear Information System (INIS)

    Yukalov, V.I.; Marzlin, K.-P.; Yukalova, E.P.; Bagnato, V.S.

    2005-01-01

    The report reviews the problem of topological coherent modes, which are nonlinear collective states of Bose-condensed atoms. Such modes can be generated by means of alternating external fields, whose frequencies are in resonance with the transition frequencies between the related modes. The Bose gas with generated topological coherent modes is a collective nonlinear analog of a resonant atom. Such systems exhibit a variety of nontrivial effects, e.g. interference fringes, interference current, mode locking, dynamic transitions, critical phenomena, chaotic motion, harmonic generation, parametric conversion, atomic squeezing, and entanglement production

  13. Connecting coherent structures and strange attractors

    Science.gov (United States)

    Keefe, Laurence R.

    1990-01-01

    A concept of turbulence derived from nonlinear dynamical systems theory suggests that turbulent solutions to the Navier-Stokes equations are restricted to strange attractors, and, by implication, that turbulent phenomenology must find some expression or source in the structure of these mathematical objects. Examples and discussions are presented to link coherent structures to some of the commonly known characteristics of strange attractors. Basic to this link is a geometric interpretation of conditional sampling techniques employed to educe coherent structures that offers an explanation for their appearance in measurements as well as their size.

  14. Coherent Synchrotron Radiation in Storage Rings

    International Nuclear Information System (INIS)

    Venturini, Marco

    2002-01-01

    We take a detour from the main theme of this volume and present a discussion of coherent synchrotron radiation (CSR) in the context of storage rings rather than single-pass systems. Interest in this topic has been revived by a series of measurements carried out at several light source facilities. There is strong evidence that the observed coherent signal is accompanied by a beam instability, possibly driven by CSR itself. In this paper we review a ''self-consistent'' model of longitudinal beam dynamics in which CSR is the only agent of collective forces. The model yields numerical solutions that appear to reproduce the main features of the observations

  15. Dental optical coherence domain reflectometry explorer

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Matthew J. (Livermore, CA); Colston, Jr., Billy W. (Livermore, CA); Sathyam, Ujwal S. (Livermore, CA); Da Silva, Luiz B. (Pleasanton, CA)

    2001-01-01

    A hand-held, fiber optic based dental device with optical coherence domain reflectometry (OCDR) sensing capabilities provides a profile of optical scattering as a function of depth in the tissue at the point where the tip of the dental explorer touches the tissue. This system provides information on the internal structure of the dental tissue, which is then used to detect caries and periodontal disease. A series of profiles of optical scattering or tissue microstructure are generated by moving the explorer across the tooth or other tissue. The profiles are combined to form a cross-sectional, or optical coherence tomography (OCT), image.

  16. Electron dynamics inside short-coherence systems

    International Nuclear Information System (INIS)

    Ferrari, Giulio; Bordone, Paolo; Jacoboni, Carlo

    2006-01-01

    We present theoretical results on electron dynamics inside nanometric systems, where the coherence of the electron ensemble is maintained in a very short region. The contacts are supposed to spoil such a coherence, therefore the interference processes between the carrier wavefunction and the internal potential profile can be affected by the proximity of the contacts. The problem has been analysed by using the Wigner-function formalism. For very short devices, transport properties, such as tunnelling through potential barriers, are significantly influenced by the distance between the contacts

  17. Hilbert W*-modules and coherent states

    International Nuclear Information System (INIS)

    Bhattacharyya, T; Roy, S Shyam

    2012-01-01

    Hilbert C*-module valued coherent states was introduced earlier by Ali, Bhattacharyya and Shyam Roy. We consider the case when the underlying C*-algebra is a W*-algebra. The construction is similar with a substantial gain. The associated reproducing kernel is now algebra valued, rather than taking values in the space of bounded linear operators between two C*-algebras. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)

  18. Coherent reflectivity using white synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Panzner, Tobias; Sant, Tushar; Pietsch, Ullrich [Universitaet Siegen (Germany). Festkoerperphysik

    2008-07-01

    Using coherent white synchrotron radiation in the hard X-ray region for reflectivity experiments one have access to sample properties on a nanometer scale in principle. To extract the wanted information from the performed measurements so called phase retrieval algorithms are necessary. The authors developed a straight forward simulation program based on a spatial limited atomic flat surface to evaluate the influence of different parameters on the coherent scattered signal in the detector plane. These simulations can explain some interesting features of the measurements and shows unexpected results for the influence of the so called illumination function.

  19. Binaural dereverberation based on interaural coherence histograms

    DEFF Research Database (Denmark)

    Westermann, Adam; Buchholz, Jorg M.; Dau, Torsten

    2013-01-01

    A binaural dereverberation algorithm is presented that utilizes the properties of the interaural coherence (IC) inspired by the concepts introduced in Allen et al. [J. Acoust. Soc. Am. 62, 912-915 (1977)]. The algorithm introduces a non-linear sigmoidal coherence-to-gain mapping that is controlled...... of the proposed algorithm was objectively and subjectively evaluated in terms of its impacts on the amount of reverberation and overall quality. A binaural spectral subtraction method based on Lebart et al. [Acta Acust. Acust. 87, 359-366 (2001)] and a binaural version of the original method of Allen et al. were...

  20. Bunch heating by coherent synchrotron radiation

    International Nuclear Information System (INIS)

    Heifets, S.A.; Zolotorev, M.

    1995-10-01

    The authors discuss here effects which define the steady-state rms energy spread of a microbunch in a storage ring. It is implied that the longitudinal microwave instability is controlled by low α lattice. In this case the coherent synchrotron radiation, if exists, may be the main factor defining the bunch temperature. Another effect comes from the fact that a nonlinear momentum compaction of such lattices makes Haissinskii equation not applicable, and the coherent synchrotron radiation may effect not only bunch lengthening but the energy spread as well