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Sample records for adiabatic-rectangular pulse train

  1. Training Ultrafast Laser Pulses

    Science.gov (United States)

    Averin, Ruslan; Wells, N.; Todt, M.; Smolnisky, N.; Jastram, N.; Jochim, B.; Gregerson, N.; Wells, E.; Sayler, A.; McKenna, J.; Carnes, K.; Ben-Itzhak, I.; Kling, M. F.

    2009-11-01

    Closed loop control of molecular processes utilizing shaped ultrafast laser pulses has been around for a number of years, yet this type of control has primarily utilized Time of Flight ion yield data for feedback. We present experiments using Velocity Map Imaging (VMI) as the feedback source for the closed loop control. Using VMI allows for pulse optimization not only with respect to the disassociation species but also angular information of the final state. We demonstrate the feasibility of incorporating this kind of feedback into the control loop. Using this technique, we controlled the dissociation branching ratio of CO^+ into C^+ +O or C ^+O^+ and used the VMI information to recover additional information about the control mechanism.

  2. Academic Training - Pulsed SC Magnets

    CERN Multimedia

    Françoise Benz

    2006-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 2, 3, June 29, 30, 31 May, 1, 2 June 11:00-12:00 - Auditorium, bldg 500 Pulsed SC Magnets by M. Wilson Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mech...

  3. Random Pulse Train Spectrum Calculation Unleashed

    OpenAIRE

    Stepanov, Sander; Venetsanopoulos, Anastasios

    2015-01-01

    For the first time the problem of the full solution for the calculation of the power spectrum density of the random pulse train is solved. This well known problem led to a mistaken publication in the past and even its partial solution was considered worthy of publication in a textbook. The little known solution for only the continues random pulse train spectrum is explained by examples and is extended to cover each signal having a discrete spectrum, too. A developed approach is used to derive...

  4. Spectral signature of short attosecond pulse trains

    CERN Document Server

    Mansten, E; Mauritsson, J; Ruchon, T; LHuillier, A; Tate, J; Gaarde, M B; Eckle, P; Guandalini, A; Holler, M; Schapper, F; Gallmann, L; Keller, U

    2008-01-01

    We report experimental measurements of high-order harmonic spectra generated in Ar using a carrier-envelope-offset (CEO) stabilized 12 fs, 800nm laser field and a fraction (less than 10%) of its second harmonic. Additional spectral peaks are observed between the harmonic peaks, which are due to interferences between multiple pulses in the train. The position of these peaks varies with the CEO and their number is directly related to the number of pulses in the train. An analytical model, as well as numerical simulations, support our interpretation.

  5. Power Spectra of Multipath Faded Pulse Trains

    OpenAIRE

    Ridolfi, Andrea; Win, Moe

    2005-01-01

    We address the problem of modeling received pulse trains in a multipath fading channel and of computing their exact spectrum. We propose a model based on point processes. Such model is very general, simple and tractable and it allows to account for various phenomena that affect the transmission. We then give the exact spectrum of the output of such a model. Spectral formula of specific configurations are then derived from a singular general formula, where the various features of the channe...

  6. High-power pulse trains excited by modulated continuous waves

    OpenAIRE

    Wang, Yan; Song, Lijun; Li, Lu; Malomed, Boris A.

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demo...

  7. A Method for Distinguishing Attosecond Single Pulse from Attosecond Pulse Train

    Institute of Scientific and Technical Information of China (English)

    HUO Yi-Ping; ZENG Zhi-Nan; LI Ru-Xin; XU Zhi-Zhan

    2004-01-01

    @@ The driving laser field assisted attosecond soft-extreme-ultraviolet (XUV) photo-ionization was used successfully to measure the duration of the attosecond pulse based on the cross-correlation method. However, this method in principle cannot distinguish a single attosecond pulse from the attosecond pulse train. We propose a technique for directly distinguishing attosecond single pulse from attosecond pulse train based on the photo-ionization of atoms by attosecond XUV pulse in the presence of a two-colour strong laser pulse.

  8. High-power pulse trains excited by modulated continuous waves

    CERN Document Server

    Wang, Yan; Li, Lu; Malomed, Boris A

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demonstrated that the double trains propagate in a robust form, with frequencies shifted by the Raman effect.

  9. Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration

    Science.gov (United States)

    Shalloo, R. J.; Corner, L.; Arran, C.; Cowley, J.; Cheung, G.; Thornton, C.; Walczak, R.; Hooker, S. M.

    2016-09-01

    In multi-pulse laser wakefield acceleration (MP-LWFA) a plasma wave is driven by a train of low-energy laser pulses separated by the plasma period, an approach which offers a route to driving plasma accelerators with high efficiency and at high pulse repetition rates using emerging technologies such as fibre and thin-disk lasers. Whilst these laser technologies are in development, proof-of-principle tests of MP-LWFA require a pulse train to be generated from a single, high-energy ultrafast pulse. Here we demonstrate the generation of trains of up to 7 pulses with pulse separations in the range 150-170 fs from single 40 fs pulses produced by a Ti:sapphire laser.

  10. Krytron switch for single pulse selection from a mode-locked pulse train

    International Nuclear Information System (INIS)

    We present detailed technical data on a Krytron switch circuit which is used for the single pulse selection from a pulse train of a mode-locked laser. Design considerations for the triggering circuit of the Krytron are described and the optimum selections of avalanche transistors are shown. Data on the delay time and life characteristics of Krytron tubes are shown. A very reliable pulse selection from a mode-locked pulse train has been realized. The amplitude variation of the selected pulse was less than +-2.5%. (author)

  11. Short pulse laser train for laser plasma interaction experiments

    International Nuclear Information System (INIS)

    A multiframe, high-time resolution pump-probe diagnostic consisting of a consecutive train of ultrashort laser pulses (∼ps) has been developed for use with a chirped pulse amplification (CPA) system. A system of high quality windows is used to create a series of 1054 nm picosecond-laser pulses which are injected into the CPA system before the pulse stretcher and amplifiers. By adding or removing windows in the pulse train forming optics, the number of pulses can be varied. By varying the distance and thickness of the respective optical elements, the time in between the pulses, i.e., the time in between frames, can be set. In our example application, the CPA pulse train is converted to 527 nm using a KDP crystal and focused into a preformed plasma and the reflected laser light due to stimulated Raman scattering is measured. Each pulse samples different plasma conditions as the plasma evolves in time, producing more data on each laser shot than with a single short pulse probe. This novel technique could potentially be implemented to obtain multiple high-time resolution measurements of the dynamics of physical processes over hundreds of picoseconds or even nanoseconds with picosecond resolution on a single shot

  12. Molecular spinning by a chiral train of short laser pulses

    CERN Document Server

    Floß, Johannes

    2012-01-01

    We provide a detailed theoretical analysis of molecular rotational excitation by a chiral pulse train -- a sequence of linearly polarised pulses with the polarisation direction rotating from pulse to pulse by a controllable angle. Molecular rotation with a preferential rotational sense (clockwise or counter-clockwise) can be excited by this scheme. We show that the directionality of the rotation is caused by quantum interference of different excitation pathways. The chiral pulse train is capable of selective excitation of molecular isotopologues and nuclear spin isomers in a mixture. We demonstrate this using 14N2 and 15N2 as examples for isotopologues, and para- and ortho-nitrogen as examples for nuclear spin isomers.

  13. Time-Grating for the Generation of STUD Pulse Trains

    Science.gov (United States)

    Zheng, Jun; Wang, Shi-Wei; Xu, Jian-Qiu

    2013-04-01

    Spike train of uneven duration or delay (STUD) pulses hold potential for laser-plasma interaction (LPI) control in laser fusion. The technique based on time grating is applied to generate an STUD pulse train. Time grating, a temporal analogy of the diffraction grating, can control the pulse width, shape, and repetition rate easily through the use of electro-optical devices. The pulse width and repetition rate are given by the modulation frequency and depth of the phase modulation function in theory and numerical calculation. The zero-chirped phase modulation is good for the compression effect of the time grating. A principle experiment of two pulses interfering is shown to verify the time grating function.

  14. Monopolar Intracochlear Pulse Trains Selectively Activate the Inferior Colliculus

    OpenAIRE

    Schoenecker, Matthew C.; Bonham, Ben H.; Stakhovskaya, Olga A.; Snyder, Russell L.; Leake, Patricia A.

    2012-01-01

    Previous cochlear implant studies using isolated electrical stimulus pulses in animal models have reported that intracochlear monopolar stimulus configurations elicit broad extents of neuronal activation within the central auditory system—much broader than the activation patterns produced by bipolar electrode pairs or acoustic tones. However, psychophysical and speech reception studies that use sustained pulse trains do not show clear performance differences for monopolar versus bipolar confi...

  15. Femtosecond laser pulse train interaction with dielectric materials

    CERN Document Server

    Caulier, O Dematteo; Chimier, B; Skupin, S; Bourgeade, A; Léger, C Javaux; Kling, R; Hönninger, C; Lopez, J; Tikhonchuk, V; Duchateau, G

    2015-01-01

    We investigate the interaction of trains of femtosecond microjoule laser pulses with dielectric materials by means of a multi-scale model. Our theoretical predictions are directly confronted with experimental observations in soda-lime glass. We show that due to the low heat conductivity, a significant fraction of the laser energy can be accumulated in the absorption region. Depending on the pulse repetition rate, the material can be heated to high temperatures even though the single pulse energy is too low to induce a significant material modification. Regions heated above the glass transition temperature in our simulations correspond very well to zones of permanent material modifications observed in the experiments.

  16. Gating attosecond pulse train generation using multicolor laser fields

    International Nuclear Information System (INIS)

    The process of high-order harmonic generation leads to the production of a train of attosecond-duration extreme ultraviolet (XUV) pulses, with one pulse emitted per optical half-cycle. For attosecond pump-probe experiments, a single, isolated attosecond pulse is preferable, requiring an almost continuous spectrum. We show experimentally and numerically that the addition of a second laser field, and later a third, at a noncommensurate frequency relative to the driving field can modify the subcycle shape of the electric field, leading to the appearance of additional spectral components between the usual odd harmonics and in some cases a quasicontinuum. We perform a parametric study of the frequency ratio between the two first laser fields, the result of which is in good agreement with theoretical selection rules. We also show numerically that using three laser frequencies from an optical parametric amplifier can achieve a single attosecond pulse from a 24-fs laser pulse.

  17. Femtosecond laser pulse train interaction with dielectric materials

    Science.gov (United States)

    Dematteo Caulier, O.; Mishchik, K.; Chimier, B.; Skupin, S.; Bourgeade, A.; Javaux Léger, C.; Kling, R.; Hönninger, C.; Lopez, J.; Tikhonchuk, V.; Duchateau, G.

    2015-11-01

    The interaction of trains of femtosecond microjoule laser pulses with dielectric materials by means of a multi-scale model is investigated. Theoretical predictions are directly confronted with experimental observations in soda-lime glass. It is shown that due to the low heat conductivity, a significant fraction of the laser energy can be accumulated in the absorption region. Depending on the pulse repetition rate, the material can be heated to high temperatures even though the single pulse energy is too low to induce a significant material modification. Regions heated above the glass transition temperature in the simulations correspond very well to zones of permanent material modifications observed in the experiments. It turns out that pulse-to-pulse variations of the laser absorption are negligible and of minor influence to permanent material modifications.

  18. Frequency Stepped Pulse Train Modulated Wind Sensing Lidar

    DEFF Research Database (Denmark)

    Olesen, Anders Sig; Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2011-01-01

    In this paper a wind sensing lidar utilizing a Frequency Stepped Pulse Train (FSPT) is demonstrated. One of the advantages in the FSTP lidar is that it enables direct measurement of wind speed as a function of distance from the lidar. Theoretically the FSPT lidar continuously produces measurement...

  19. Pulse-train control of photofragmentation at constant field energy

    DEFF Research Database (Denmark)

    Tiwari, Ashwani Kumar; Henriksen, Niels Engholm

    2014-01-01

    *←IBr → I + Br, changes as a function of time delay when the two excited wave packets interfere. The underlying mechanisms are analyzed and the change in the branching ratio as a function of time delay is only a reflection of a changing frequency distribution of the pulse train; the branching ratio does...

  20. Hand-held pulse-train-analysis instrument

    International Nuclear Information System (INIS)

    A portable hand-held pulse-train-analysis instrument uses a number-oriented microprocessor sequenced by a single component microprocessor. The incorporation of new CMOS integrated circuits makes possible complex analysis in a small, easily operated, battery-powered unit. The instrument solves an immediate problem with threshold setting of plastic scintillators and promises numerous other applications

  1. Attosecond pulse trains as multi-color coherent control

    CERN Document Server

    Hernández, J V

    2009-01-01

    We present a general description of the interaction between multi-color laser pulses and atoms and molecules, focusing on the experimentally relevant example of infrared (IR) pulses overlapped with attosecond pulse trains (APTs). This formulation reveals explicitly and analytically the role of the delay between the IR pulse and APT as a coherent control parameter. Our formulation also shows the nearly equivalent roles of the delay and the carrier-envelope phase in controlling the interference between different multiphoton pathways. We illustrate these points by investigating the single ionization of He and introduce dressed adiabatic hyperspherical potentials to aid the discussion. We confirm the predictions with a full-dimensional, two-electron solution of the time-dependent Schr\\"odinger equation.

  2. Delaying Trains of Short Light Pulses in WGM Resonators

    Science.gov (United States)

    Matsko, Andrey; Iltchenko, Vladimir; Strekalov, Dmitry; Savchenkov, Anatoliy; Maleki, Lute

    2008-01-01

    Suitably configured whispering-gallery-mode (WGM) optical resonators have been proposed as delay lines for trains of short light pulses. Until now, it has been common practice to implement an optical delay line as a coiled long optical fiber, which is bulky and tends to be noisy. An alternative has been to implement an optical delay line as a coupled-resonator optical waveguide (a chain of coupled optical resonators), which is compact but limits the width of the pulse spectrum to the width of an optical resonance and thereby places a lower limit on the duration of a pulse. In contrast, a delay line according to the proposal could be implemented as a single WGM resonator, and the pulses delayed by the resonator could be so short that their spectral widths could greatly exceed the spectral width of any single resonance. The proposal emerged from theoretical and experimental studies of the propagation of a pulse train in a WGM resonator. An important element of the theoretical study was recognition that the traditional definition of group velocity in effect, the velocity of a single pulse comprising a packet of waves propagating in a medium, the responsivity of which is a monotonous function of frequency does not necessarily apply in the case of a WGM resonator or other medium having a spectrum consisting of discrete resonance peaks at different frequencies. A new definition of group velocity, applicable to a train of pulses propagating in such a medium, was introduced and found to lead to the discovery of previously unknown features of propagation. Notably, it was found that in a micro - sphere optical resonator that supports a suitable combination of WGM modes, the group velocity for a train of light pulses could be positive, zero, or negative. A positive group velocity could be so small that the delay could be much longer than the ring-down time of the resonator; a delay of such great length is impossible for a single pulse interacting with either a linearly

  3. Development of a compact soft X-ray laser using a pulse-train laser. 4

    International Nuclear Information System (INIS)

    Time behaviour of gain coefficients was studied for the two different pulse train-lasers; one is a normal pulse-train, and the other modified one. The duration time of gain is larger for the modified pulse-train laser compared with the normal one. (author)

  4. Femtosecond-pulse-train ionization of Rydberg wave packets

    OpenAIRE

    Simonsen, Sigrid Ina; Sørngård, Stian Astad; Førre, Morten; Hansen, Jan Petter

    2012-01-01

    We calculate, based on first-order perturbation theory, the total and differential ionization probabilities from a dynamic periodic Rydberg wave packet of a given n-shell exposed to a train of femtosecond laser pulses. The total probability is shown to depend crucially on the laser repetition rate: For certain frequencies the ionization probability vanishes, while for others it becomes very large. The origin of this effect is the strong dependence of the ionization probability on ...

  5. Spectral Effects for an Ultrashort Pulse Train Propagating in a Two-Level Atom Medium

    Institute of Scientific and Technical Information of China (English)

    LIU Bing-Xin; GONG Shang-Qing; SONG Xiao-Hong; LI Ru-Xin; XU Zhi-Zhan

    2005-01-01

    @@ We investigate the spectra of a femtosecond pulse train propagating in a resonant two-level atom (TLA) medium.It is found that higher spectral components can be produced even for a 2π femtosecond pulse train. Furthermore,the spectral effects depend crucially on both the relative shift φ and the delay time τ between the successive pulses of the femtosecond pulse train.

  6. Modulated pumping in Cs with picosecond pulse trains

    International Nuclear Information System (INIS)

    Two different experimental arrangements were used for periodic excitation detection of coherence. Cs vapor in a gas cell was resonantly excited on the D2 line by a train of ultrashort light pulses of circular polarization. To reduce transit-time broadening, additional buffer gas was contained in the cell and the light beam from a laser was expanded to a cross section of about 1.5 cm2. The resulting atomic coherence amplitude which was due to the periodic excitation of atoms could then be measured by different means. The experimental set-up is shown which takes advantage of the fact that atomic coherence gives rise to an oscillating optical anisotropy in the sample. The atomic splitting is measured by the 9th harmonic of the injection laser pulse rate with a width of less than 50 Hz. The experiments demonstrate the ultrahigh frequency resolution is possible with optical pulse train interference spectroscopy which allows one to sensitively detect small pressure shifts in the hyperfine frequency caused by buffer gases in the gas cell

  7. Spectrum analysis of all parameter noises in repetition-rate laser pulse train

    Institute of Scientific and Technical Information of China (English)

    Junhua Tang; Yuncai Wang

    2006-01-01

    @@ The theoretical investigation of all parameter noises in repetition-rate laser pulse train was presented. The expression of power spectrum of laser pulse trains with all parameter noises was derived, and the power spectra of pulse trains with different noise parameters were numerically simulated. By comparing the power spectra with and without pulse-width jitter, we noted that pulse-width jitter could not be neglected compared with amplitude noise and timing jitter and contributed a great amount of noise into the power spectrum under the condition that the product of pulse width and angular frequency was larger than 1.

  8. Frequency Stepped Pulse Train Modulated Wind Sensing Lidar

    OpenAIRE

    Olesen, Anders Sig; Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2011-01-01

    In this paper a wind sensing lidar utilizing a Frequency Stepped Pulse Train (FSPT) is demonstrated. One of the advantages in the FSTP lidar is that it enables direct measurement of wind speed as a function of distance from the lidar. Theoretically the FSPT lidar continuously produces measurements as is the case with a CW lidar, but at the same time with a spatial resolution, and without the range ambiguity originating from e.g. clouds. The FSPT lidar utilizes a frequency sweeping source for ...

  9. Transporting Rydberg Electron Wave Packets with Chirped Trains of Pulses

    International Nuclear Information System (INIS)

    A protocol for steering Rydberg electrons towards targeted final states is realized with the aid of a chirped train of half-cycle pulses (HCPs). Its novel capabilities are demonstrated experimentally by transporting potassium atoms excited to the lowest-lying quasi-one-dimensional states in the ni=350 Stark manifold to a narrow range of much higher-n states. We demonstrate that this coherent state transfer is, to a high degree, reversible. The protocol allows for remarkable selectivity and is highly efficient, with typically over 80% of the parent atoms surviving the HCP sequence

  10. Control of molecular rotation with a chiral train of ultrashort pulses

    CERN Document Server

    Zhdanovich, S; Bloomquist, C; Floß, J; Averbukh, I Sh; Hepburn, J W; Milner, V

    2011-01-01

    Trains of ultrashort laser pulses separated by the time of rotational revival (typically, tens of picoseconds) have been exploited for creating ensembles of aligned molecules. In this work we introduce a chiral pulse train - a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. The chirality of such a train, expressed through the period and direction of its polarization rotation, is used as a new control parameter for achieving selectivity and directionality of laser-induced rotational excitation. The method employs chiral trains with a large number of pulses separated on the time scale much shorter than the rotational revival (a few hundred femtosecond), enabling the use of conventional pulse shapers.

  11. Pulse train amplification and regeneration based on semiconductor quantum dots waveguide

    DEFF Research Database (Denmark)

    Chen, Yaohui; Öhman, Filip; Mørk, Jesper

    2008-01-01

    We numerical analyze pulse train amplification up to 200 Gbit/s in quantum dot amplifiers and present regeneration properties with saturable absorber based on semiconductor quantum dot waveguides.......We numerical analyze pulse train amplification up to 200 Gbit/s in quantum dot amplifiers and present regeneration properties with saturable absorber based on semiconductor quantum dot waveguides....

  12. Design and Characteristic Analysis of Multicarrier Chaotic Phase Coded Radar Pulse Train Signal

    Directory of Open Access Journals (Sweden)

    Qiongdan Huang

    2014-01-01

    Full Text Available By introducing phase code into multicarrier orthogonal frequency division multiplex signal, the multicarrier phase coded (MCPC radar signal possesses a good spectrum utilization rate and can achieve a good combination of narrowband and wideband processing. Radar pulse train signal not only reserves the high range resolution of monopulse signal, but also has the same velocity resolution performance as continuous wave signal does. In this study, we use the chaotic biphase code generated by Chebyshev mapping to conduct a phase modulation on MCPC pulse train so as to design two different types of multicarrier chaotic phase coded pulse train signal. The ambiguity functions of the two pulse train signals are compared with that of P4 code MCPC pulse train. In addition, we analyze the influences of subcarrier number, phase-modulated bit number, and period number on the pulse train’s autocorrelation performance. The low probability of intercept (LPI performance of the two signals is also discussed. Simulation results show that the designed pulse train signals have a thumbtack ambiguity function, a periodic autocorrelation side lobe lower than P4 code MCPC pulse train, and excellent LPI performance, as well as the feature of waveform diversity.

  13. Temporal Characterization of individual Harmonics of an attosecond pulse train by THz Streaking

    CERN Document Server

    Ardana-Lamas, F; Stepanov, A; Gorgisyan, I; Juranic, P; Abela, R; Hauri, C P

    2015-01-01

    We report on the global temporal pulse characteristics of individual harmonics in an attosecond pulse train by means of photo-electron streaking in a strong low-frequency transient. The scheme allows direct retrieval of pulse durations and first order chirp of individual harmonics without the need of temporal scanning. The measurements were performed using an intense THz field generated by tilted phase front technique in LiNbO_3 . Pulse properties for harmonics of order 23, 25 and 27 show that the individual pulse durations and linear chirp are decreasing by the harmonic order.

  14. High harmonic attosecond pulse train amplification in a free electron laser

    International Nuclear Information System (INIS)

    It is shown using three-dimensional simulations that the temporal structure of an attosecond pulse train, such as that generated via high harmonic generation in noble gases, may be retained in a free electron laser amplifier through to saturation using a mode-locked optical klystron configuration. At wavelengths of ∼12 nm, a train of attosecond pulses of widths ∼300 as with peak powers in excess of 1 GW are predicted.

  15. Plasma production by a train of nanosecond CO2 laser pulses

    International Nuclear Information System (INIS)

    The first experimental study of the electric fields and currents which accompany the breakdown of air by a train of nanosecond CO2-laser pulses near the surface of an uncharged (copper) target is reported. Bombardment with a train of nanosecond laser pulses leads to a lowering of the threshold for plasma production, to an increase in the efficiency at which energy is transferred to the target, and to the excitation of high-frequency (1 GHz) electric fields and currents. 8 references

  16. Interaction Of CO2 Laser Nanosecond Pulse Train With The Metallic Targets In Optical Breakdown Regime

    Science.gov (United States)

    Apollonov, V. V.; Firsov, K. N.; Konov, V. I.; Nikitin, P. I.; Prokhorov, A. M.; Silenok, A. S.; Sorochenko, V. R.

    1986-11-01

    In the present paper the electric field and currents in the air-breakdown plasma, produced by the train of nanosecond pulses of TEA-002 - regenerative amplifier near the un-charged targets are studied. The breakdown thresholds and the efficiency of plasma-target heat transmission are also measured. The results of numerical calculations made for increasing of the pulse train contrast with respect to the background in a regenerative amplifier are advanced.

  17. Bioacoustical Periodic Pulse Train Signal Detection and Classification using Spectrogram Intensity Binarization and Energy Projection

    OpenAIRE

    Marian POPESCU; Dugan, Peter J.; Pourhomayoun, Mohammad; Risch, Denise; Harold W. Lewis III; Clark, Christopher W.

    2013-01-01

    The following work outlines an approach for automatic detection and recognition of periodic pulse train signals using a multi-stage process based on spectrogram edge detection, energy projection and classification. The method has been implemented to automatically detect and recognize pulse train songs of minke whales. While the long term goal of this work is to properly identify and detect minke songs from large multi-year datasets, this effort was developed using sounds off the coast of Mass...

  18. Pulse-train nonuniformity in an all-fiber ring laser passively mode-locked by nonlinear polarization rotation

    Institute of Scientific and Technical Information of China (English)

    Luo Zhi-Chao; Xu Wen-Cheng; Song Chuang-Xing; Luo Ai-Ping; Chen Wei-Cheng

    2009-01-01

    This paper reports the periodic power variation of the pulse-train in a passively mode-locked soliton fiber ring laser. It can obtain either the uniform or nonuniform pulse-train output by simply rotating the polarization controllers.The experimental results show that the pulse-train nonuniformity is caused by the interaction between the nonuniform polarization states of the soliton pulses and the passive polarizer in the cavity.

  19. Time-resolved reconstruction of dynamical pulse trains using multiheterodyne detection

    Science.gov (United States)

    Butler, T.; Tykalewicz, B.; Goulding, D.; Kelleher, B.; Huyet, Guillaume; Hegarty, S. P.

    2014-05-01

    A technique has been developed for the measurement of pulse trains demonstrating a dynamical behaviour (i.e. not ideally periodic). Existing techniques in this area (e.g. FROG, SPIDER or other heterodyne methods) require very stable pulse trains, or large averaging times, and so are limited when applied to even slowly varying pulse trains. The technique presented involves mixing the comb under test (CUT) with a reference optical frequency comb (OFC) which has a known spectral intensity profile. Mixing these signals on a photodiode results in a series of radio frequency (RF) beat tones. The phase properties of these beat tones can be used to measure the spectral phase between adjacent modes in the CUT, allowing the full complex spectrum of the CUT to be measured simultaneously with one single real time oscilloscope acquisition. With the spectral properties of the comb known, the pulse train can be reconstructed in the temporal domain. By applying this technique to very small sections of the beating signal ( tens of nanoseconds), a time resolved picture of the pulse train behaviour can be obtained. Dynamic signals generated in a LiNbO3 modulator driven by a modulated RF signal have been measured. This technique is well suited to studying the combs produced by mode-locked semiconductor lasers. Quantum dot mode-locked laser combs can be characterised, and pulse train instabilities measured.

  20. Fast simulation and optimization of pulse-train chemical exchange saturation transfer (CEST) imaging

    International Nuclear Information System (INIS)

    Chemical exchange saturation transfer (CEST) MRI has been increasingly applied to detect dilute solutes and physicochemical properties, with promising in vivo applications. Whereas CEST imaging has been implemented with continuous wave (CW) radio-frequency irradiation on preclinical scanners, pulse-train irradiation is often chosen on clinical systems. Therefore, it is necessary to optimize pulse-train CEST imaging, particularly important for translational studies. Because conventional Bloch–McConnell formulas are not in the form of homogeneous differential equations, the routine simulation approach simulates the evolving magnetization step by step, which is time consuming. Herein we developed a computationally efficient numerical solution using matrix iterative analysis of homogeneous Bloch–McConnell equations. The proposed algorithm requires simulation of pulse-train CEST MRI magnetization within one irradiation repeat, with 99% computation time reduction from that of conventional approach under typical experimental conditions. The proposed solution enables determination of labile proton ratio and exchange rate from pulse-train CEST MRI experiment, within 5% from those determined from quantitative CW-CEST MRI. In addition, the structural similarity index analysis shows that the dependence of CEST contrast on saturation pulse flip angle and duration between simulation and experiment was 0.98  ±  0.01, indicating that the proposed simulation algorithm permits fast optimization and quantification of pulse-train CEST MRI. (paper)

  1. Fast simulation and optimization of pulse-train chemical exchange saturation transfer (CEST) imaging.

    Science.gov (United States)

    Xiao, Gang; Sun, Phillip Zhe; Wu, Renhua

    2015-06-21

    Chemical exchange saturation transfer (CEST) MRI has been increasingly applied to detect dilute solutes and physicochemical properties, with promising in vivo applications. Whereas CEST imaging has been implemented with continuous wave (CW) radio-frequency irradiation on preclinical scanners, pulse-train irradiation is often chosen on clinical systems. Therefore, it is necessary to optimize pulse-train CEST imaging, particularly important for translational studies. Because conventional Bloch-McConnell formulas are not in the form of homogeneous differential equations, the routine simulation approach simulates the evolving magnetization step by step, which is time consuming. Herein we developed a computationally efficient numerical solution using matrix iterative analysis of homogeneous Bloch-McConnell equations. The proposed algorithm requires simulation of pulse-train CEST MRI magnetization within one irradiation repeat, with 99% computation time reduction from that of conventional approach under typical experimental conditions. The proposed solution enables determination of labile proton ratio and exchange rate from pulse-train CEST MRI experiment, within 5% from those determined from quantitative CW-CEST MRI. In addition, the structural similarity index analysis shows that the dependence of CEST contrast on saturation pulse flip angle and duration between simulation and experiment was 0.98 ± 0.01, indicating that the proposed simulation algorithm permits fast optimization and quantification of pulse-train CEST MRI. PMID:26020414

  2. Generation of time-dependent ultra-short optical pulse trains in the presence of self-steepening effect

    Institute of Scientific and Technical Information of China (English)

    Zhong Xian-Qiong; Xiang An-Ping

    2009-01-01

    Starting from the extended nonlinear Schrodinger equation in which the self-steepening effect is included, the evolution and the splitting processes of continuous optical wave whose amplitude is perturbed into time related ultra-short optical pulse trains in an optical fibre are numerically simulated by adopting the split-step Fourier algorithm. The results show that the self-steepening effect can cause the characteristic of the pulse trains to vary with time, which is different from the self-steepening-free case where the generated pulse trains consist of single pulses which are identical in width, intensity, and interval, namely when pulses move a certain distance, they turn into the pulse trains within a certain time range. Moreover, each single pulse may split into several sub-pulses. And as timc gocs on, the number of the sub-pulses will decrease gradually and the pulse width and the pulse intcnsity will change too. With the increase of the self-steepening parameter, the distance needed to generate time-dependent pulse trains will shorten. In addition, for a large self-steepening parameter and at the distance where more sub-pulses appear, the corresponding frequency spectra of pulse trains are also wider.

  3. Extraction of pulse repetition intervals from sperm whale click trains for ocean acoustic data mining.

    Science.gov (United States)

    Zaugg, Serge; van der Schaar, Mike; Houégnigan, Ludwig; André, Michel

    2013-02-01

    The analysis of acoustic data from the ocean is a valuable tool to study free ranging cetaceans and anthropogenic noise. Due to the typically large volume of acquired data, there is a demand for automated analysis techniques. Many cetaceans produce acoustic pulses (echolocation clicks) with a pulse repetition interval (PRI) remaining nearly constant over several pulses. Analyzing these pulse trains is challenging because they are often interleaved. This article presents an algorithm that estimates a pulse's PRI with respect to neighboring pulses. It includes a deinterleaving step that operates via a spectral dissimilarity metric. The sperm whale (SW) produces trains with PRIs between 0.5 and 2 s. As a validation, the algorithm was used for the PRI-based identification of SW click trains with data from the NEMO-ONDE observatory that contained other pulsed sounds, mainly from ship propellers. Separation of files containing SW clicks with a medium and high signal to noise ratio from files containing other pulsed sounds gave an area under the receiver operating characteristic curve value of 0.96. This study demonstrates that PRI can be used for the automated identification of SW clicks and that deinterleaving via spectral dissimilarity contributes to algorithm performance. PMID:23363108

  4. Performance investigation of the pulse and Campbelling modes of a fission chamber using a Poisson pulse train simulation code

    Science.gov (United States)

    Elter, Zs.; Jammes, C.; Pázsit, I.; Pál, L.; Filliatre, P.

    2015-02-01

    The detectors of the neutron flux monitoring system of the foreseen French GEN-IV sodium-cooled fast reactor (SFR) will be high temperature fission chambers placed in the reactor vessel in the vicinity of the core. The operation of a fission chamber over a wide-range neutron flux will be feasible provided that the overlap of the applicability of its pulse and Campbelling operational modes is ensured. This paper addresses the question of the linearity of these two modes and it also presents our recent efforts to develop a specific code for the simulation of fission chamber pulse trains. Our developed simulation code is described and its overall verification is shown. An extensive quantitative investigation was performed to explore the applicability limits of these two standard modes. It was found that for short pulses the overlap between the pulse and Campbelling modes can be guaranteed if the standard deviation of the background noise is not higher than 5% of the pulse amplitude. It was also shown that the Campbelling mode is sensitive to parasitic noise, while the performance of the pulse mode is affected by the stochastic amplitude distributions.

  5. Performance investigation of the pulse and Campbelling modes of a fission chamber using a Poisson pulse train simulation code

    Energy Technology Data Exchange (ETDEWEB)

    Elter, Zs. [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 Saint-Paul-lez-Durance (France); Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Göteborg (Sweden); Jammes, C., E-mail: christian.jammes@cea.fr [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 Saint-Paul-lez-Durance (France); Pázsit, I. [Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Göteborg (Sweden); Pál, L. [Centre for Energy Research, Hungarian Academy of Sciences, H-1525 Budapest 114, POB 49 (Hungary); Filliatre, P. [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 Saint-Paul-lez-Durance (France)

    2015-02-21

    The detectors of the neutron flux monitoring system of the foreseen French GEN-IV sodium-cooled fast reactor (SFR) will be high temperature fission chambers placed in the reactor vessel in the vicinity of the core. The operation of a fission chamber over a wide-range neutron flux will be feasible provided that the overlap of the applicability of its pulse and Campbelling operational modes is ensured. This paper addresses the question of the linearity of these two modes and it also presents our recent efforts to develop a specific code for the simulation of fission chamber pulse trains. Our developed simulation code is described and its overall verification is shown. An extensive quantitative investigation was performed to explore the applicability limits of these two standard modes. It was found that for short pulses the overlap between the pulse and Campbelling modes can be guaranteed if the standard deviation of the background noise is not higher than 5% of the pulse amplitude. It was also shown that the Campbelling mode is sensitive to parasitic noise, while the performance of the pulse mode is affected by the stochastic amplitude distributions.

  6. Simulations of drastically reduced SBS with laser pulses composed of a Spike Train of Uneven Duration and Delay (STUD pulses)

    CERN Document Server

    Hüller, Stefan

    2012-01-01

    By comparing the impact of established laser smoothing techniques like Random Phase Plates (RPP) and Smoothing by Spectral Dispersion (SSD) to the concept of "Spike Trains of Uneven Duration and Delay" (STUD pulses) on the amplification of parametric instabilities in laser-produced plasmas, we show with the help of numerical simulations, that STUD pulses can drastically reduce instability growth by orders of magnitude. The simulation results, obtained with the code {\\sc Harmony} in a nonuniformly flowing mm-size plasma for the Stimulated Brillouin Scattering (SBS) instability, show that the efficiency of the STUD pulse technique is due to the fact that successive re-amplification in space and time of parametrically excited plasma waves inside laser hot spots is minimized. An overall mean fluctuation level of ion acoustic waves at low amplitude is established because of the frequent change of the speckle pattern in successive spikes. This level stays orders of magnitude below the levels of ion acoustic waves e...

  7. Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating aluminium alloy plate

    Science.gov (United States)

    Zhang, Wei; Jin, Guangyong; Gu, Xiu-ying

    2014-12-01

    Based on Von Mises yield criterion and elasto-plastic constitutive equations, an axisymmetric finite element model of a Gaussian laser beam irradiating a metal substrate was established. In the model of finite element, the finite difference hybrid algorithm is used to solve the problem of transient temperature field and stress field. Taking nonlinear thermal and mechanical properties into account, transient distributions of temperature field and stress fields generated by the pulse train of long-pulse laser in a piece of aluminium alloy plate were computed by the model. Moreover,distributions as well as histories of temperature and stress fields were obtained. Finite element analysis software COMSOL is used to simulate the Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating 7A04 aluminium alloy plate. By the analysis of the results, it is found that Mises equivalent stress on the target surface distribute within the scope of the center of a certain radius. However, the stress is becoming smaller where far away from the center. Futhermore, the Mises equivalent stress almost does not effect on stress damage while the Mises equivalent stress is far less than the yield strength of aluminum alloy targets. Because of the good thermal conductivity of 7A04 aluminum alloy, thermal diffusion is extremely quick after laser irradiate. As a result, for the multi-pulsed laser, 7A04 aluminum alloy will not produce obvious temperature accumulation when the laser frequency is less than or equal to 10 Hz. The result of this paper provides theoretical foundation not only for research of theories of 7A04 aluminium alloy and its numerical simulation under laser radiation but also for long-pulse laser technology and widening its application scope.

  8. Frequency modulated few-cycle optical pulse trains induced controllable ultrafast coherent population oscillations in three-level atomic systems

    OpenAIRE

    Kumar, Parvendra; Sarma, Amarendra K.

    2012-01-01

    We report a study on the ultrafast coherent population oscillations (UCPO) in two level atoms induced by the frequency modulated few-cycle optical pulse train. The phenomenon of UCPO is investigated by numerically solving the optical Bloch equations beyond the rotating wave approximation. We demonstrate that the quantum state of the atoms and the frequency of UCPO may be controlled by controlling the number of pulses in the pulse trains and the pulse repetition time respectively. Moreover, th...

  9. Broadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period

    Science.gov (United States)

    Lu, Xingyu; Trébosc, Julien; Lafon, Olivier; Carnevale, Diego; Ulzega, Simone; Bodenhausen, Geoffrey; Amoureux, Jean-Paul

    2013-11-01

    We analyze the direct excitation of wide one-dimensional spectra of nuclei with spin I = 1/2 or 1 in rotating solids submitted to pulse trains in the manner of Delays Alternating with Nutations for Tailored Excitation (DANTE), either with one short rotor-synchronized pulse of duration τp in each of K rotor periods (D1K) or with N interleaved equally spaced pulses τp in each rotor period, globally also extending over K rotor periods (DNK). The excitation profile of DNK scheme is a comb of rf-spikelets with NνR = N/TR spacing from the carrier frequency, and a width of each spikelet inversely proportional to the length, KTR, of DNK scheme. Since the individual pulse lengths, τp, are typically of a few hundreds of ns, DNK scheme can readily excite spinning sidebands families covering several MHz, provided the rf carrier frequency is close enough to the resonance frequency of one the spinning sidebands. If the difference of isotropic chemical shifts between distinct chemical sites is less than about 1.35/(KTR), DNK scheme can excite the spinning sidebands families of several sites. For nuclei with I = 1/2, if the homogeneous and inhomogeneous decays of coherences during the DANTE sequence are neglected, the K pulses of a D1K train have a linearly cumulative effect, so that the total nutation angle is θtot = K2πν1τp, where ν1 is the rf-field amplitude. This allows obtaining nearly ideal 90° pulses for excitation or 180° rotations for inversion and refocusing across wide MAS spectra comprising many spinning sidebands. If one uses interleaved DANTE trains DNK with N > 1, only spinning sidebands separated by intervals of NνR with respect to the carrier frequency are observed as if the effective spinning speed was NνR. The other sidebands have vanishing intensities because of the cancellation of the N contributions with opposite signs. However, the intensities of the remaining sidebands obey the same rules as in spectra obtained with νR. With increasing N, the

  10. Noise characterization of a pulse train generated by actively mode-locked lasers

    OpenAIRE

    Eliyahu, Danny; Salvatore, Randal A.; Yariv, Amnon

    1996-01-01

    We analyze the entire power spectrum of pulse trains generated by a continuously operating actively mode-locked laser in the presence of noise. We consider the effect of amplitude, pulse-shape, and timing-jitter fluctuations that are characterized by stationary processes. Effects of correlations between different parameters of these fluctuations are studied also. The nonstationary timing-jitter fluctuations of passively mode-locked lasers and their influence on the power spectrum is discussed...

  11. Analysis of shot noise in the detection of ultrashort optical pulse trains

    OpenAIRE

    Quinlan, Franklyn; Fortier, Tara M.; Jiang, Haifeng; Diddams, Scott A.

    2013-01-01

    We present a frequency domain model of shot noise in the photodetection of ultrashort optical pulse trains using a time-varying analysis. Shot noise-limited photocurrent power spectral densities, signal-to-noise expressions, and shot noise spectral correlations are derived that explicitly include the finite response of the photodetector. It is shown that the strength of the spectral correlations in the shot noise depends on the optical pulse width, and that these correlations can create order...

  12. Cooperative emission of a pulse train in an optically thick scattering medium

    CERN Document Server

    Kwong, C C; Delande, D; Pierrat, R; Wilkowski, D

    2015-01-01

    An optically thick cold atomic cloud emits a coherent flash of light in the forward direction when the phase of an incident probe field is abruptly changed. Due to cooperativity, the duration of this phenomena can be much shorter than the excited lifetime of a single atom and, surprisingly, it weakly depends on the temperature of the gas and on the probe frequency. Repeating periodically the abrupt change of the incident field phase, we generate a forward transmitted train of pulses with short repetition time. It is even possible to quench single atom fluorescence, transferring almost completely the incident power into the pulse train with a high intensity contrast.

  13. Coherent hard x rays from attosecond pulse train-assisted harmonic generation.

    Science.gov (United States)

    Klaiber, Michael; Hatsagortsyan, Karen Z; Müller, Carsten; Keitel, Christoph H

    2008-02-15

    High-order harmonic generation from atomic systems is considered in the crossed fields of a relativistically strong infrared laser and a weak attosecond pulse train of soft x rays. Due to one-photon ionization by the x-ray pulse, the ionized electron obtains a starting momentum that compensates the relativistic drift, which is induced by the laser magnetic field, and allows the electron to efficiently emit harmonic radiation upon recombination with the atomic core in the relativistic regime. This way, short pulses of coherent hard x rays of up to 40 keV energy can be generated. PMID:18278127

  14. Complex Spectra Structure of an Attosecond Pulse Train Driven by Sub-5-fs Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    YUN Chen-Xia; TENG Hao; ZHANG Wei; WANG Li-Feng; ZHAN Min-Jie; HE Xin-Kui; WANG Bing-Bing; WEI Zhi-Yi

    2011-01-01

    We present the observation of the additional spectral components between the odd order harmonics in the harmonic spectrum generated from argon gas driven by sub-5-fs laser pulses.The theoretical analysis shows that the asymmetric laser field in both spatial and temporal domains leads to this complicated spectrum structure of high order harmonics.

  15. Development of an X-ray microscope using a pulse train laser

    International Nuclear Information System (INIS)

    A pulse train laser with energy of 1 J was used to produce high intensity X-ray. We developed a soft X-ray microscope using a laser plasma X-ray source and an X-ray zooming tube. An X-ray image of Cu 2000 mesh was observed. (author)

  16. Observation of Electromagnetically Induced Transparency by a Train of Short Pulses

    Institute of Scientific and Technical Information of China (English)

    YE Cun-Yun

    2004-01-01

    @@ We report the experimental demonstration of electromagnetically induced transparency in hot rubidium (85 Rb)atomic vapour by using an actively mode-locked external cavity diode laser in Littman-Metcalf configuration.We can make opaque resonant transitions transparent to any two optical comb components in the pulse trains which excite atomic coherence in the ground states of 85Rb.

  17. Selective triggering of phase change in dielectrics by femtosecond pulse trains based on electron dynamics control

    Institute of Scientific and Technical Information of China (English)

    Xu Chuan-Cai; Jiang Lan; Leng Ni; Liu Peng-Jun

    2013-01-01

    In this study we experimentally reveal that the phase change mechanism can be selectively triggered by shaping femtosecond pulse trains based on electron dynamics control (EDC),including manipulation of excitations,ionizations,densities,and temperatures of electrons.By designing the pulse energy distribution to adjust the absorptions,excitations,ionizations,and recombinations of electrons,the dominant phase change mechanism experiences transition from nonthermal to thermal process.This phenomenon is observed in quadruple,triple,and double pulses per train ablation of fused silica separately.This opens up possibilities for controlling phase change mechanisms by EDC,which is of great significance in laser processing of dielectrics and fabrication of integrated nano-and micro-optical devices.

  18. Phase Noise and Intensity Noise of the Pulse Train Generated from Mode-locked Lasers in the Demodulation Measurement

    OpenAIRE

    Wu, Kan; Shum, Ping

    2010-01-01

    The phase noise and intensity noise of a pulse train are theoretically analyzed in the demodulation measurement. The effect of pulse asymmetry is discussed for the first time using Fourier series. Experimentally, photodetectors with different bandwidth and incident power levels are compared to achieve minimum pulse distortion.

  19. Simulations of drastically reduced SBS with laser pulses composed of a Spike Train of Uneven Duration and Delay (STUD pulses)

    International Nuclear Information System (INIS)

    By comparing the impact of established laser smoothing techniques like Random Phase Plates (RPP) and Smoothing by Spectral Dispersion (SSD) to the concept of 'Spike Trains of Uneven Duration and Delay' (STUD pulses) on the amplification of parametric instabilities in laser-produced plasmas, we show with the help of numerical simulations, that STUD pulses can drastically reduce instability growth by orders of magnitude. The simulation results, obtained with the code Harmony in a nonuniformly flowing mm-size plasma for the Stimulated Brillouin Scattering (SBS) instability, show that the efficiency of the STUD pulse technique is due to the fact that successive re-amplification in space and time of parametrically excited plasma waves inside laser hot spots is minimized. An overall mean fluctuation level of ion acoustic waves at low amplitude is established because of the frequent change of the speckle pattern in successive spikes. This level stays orders of magnitude below the levels of ion acoustic waves excited in hot spots of RPP and SSD laser beams. (authors)

  20. Simulations of drastically reduced SBS with laser pulses composed of a Spike Train of Uneven Duration and Delay (STUD pulses)

    Science.gov (United States)

    Hüller, Stefan; Afeyan, Bedros

    2013-11-01

    By comparing the impact of established laser smoothing techniques like Random Phase Plates (RPP) and Smoothing by Spectral Dispersion (SSD) to the concept of "Spike Trains of Uneven Duration and Delay" (STUD pulses) on the amplification of parametric instabilities in laser-produced plasmas, we show with the help of numerical simulations, that STUD pulses can drastically reduce instability growth by orders of magnitude. The simulation results, obtained with the code Harmony in a nonuniformly flowing mm-size plasma for the Stimulated Brillouin Scattering (SBS) instability, show that the efficiency of the STUD pulse technique is due to the fact that successive re-amplification in space and time of parametrically excited plasma waves inside laser hot spots is minimized. An overall mean fluctuation level of ion acoustic waves at low amplitude is established because of the frequent change of the speckle pattern in successive spikes. This level stays orders of magnitude below the levels of ion acoustic waves excited in hot spots of RPP and SSD laser beams.

  1. Simulations of drastically reduced SBS with laser pulses composed of a Spike Train of Uneven Duration and Delay (STUD pulses

    Directory of Open Access Journals (Sweden)

    Hüller Stefan

    2013-11-01

    Full Text Available By comparing the impact of established laser smoothing techniques like Random Phase Plates (RPP and Smoothing by Spectral Dispersion (SSD to the concept of “Spike Trains of Uneven Duration and Delay” (STUD pulses on the amplification of parametric instabilities in laser-produced plasmas, we show with the help of numerical simulations, that STUD pulses can drastically reduce instability growth by orders of magnitude. The simulation results, obtained with the code Harmony in a nonuniformly flowing mm-size plasma for the Stimulated Brillouin Scattering (SBS instability, show that the efficiency of the STUD pulse technique is due to the fact that successive re-amplification in space and time of parametrically excited plasma waves inside laser hot spots is minimized. An overall mean fluctuation level of ion acoustic waves at low amplitude is established because of the frequent change of the speckle pattern in successive spikes. This level stays orders of magnitude below the levels of ion acoustic waves excited in hot spots of RPP and SSD laser beams.

  2. A Search for Dying Pulse Trains in Cyg X-1 using RXTE

    CERN Document Server

    Dolan, Joseph F

    2011-01-01

    Dying pulse trains (DPTs) pulses of radiation with decreasing intensity and decreasing intervals between them are predicted by General Relativity to occur from material spiraling into an event horizon after detaching from the last stable orbit in an accretion disk around a black hole. Two events resembling DPTs were detected in 3 hours observation of Cyg X-1 in the far UV using the High Speed Photometer on the Hubble Space Telescope (Dolan 2001). We observed Cyg X-1, a leading candidate for a black hole, with the proportional counter array on RXTE to seek such events in the low-energy X-ray region. No dying pulse trains with a characteristic timescale between pulses of 1 - 40 ms were detected in 10 hours of observation during Cyg X-1s high luminosity state, low luminosity state, and transitions between states, although individual pulses are clearly detectable in data with 1 ms temporal resolution. The 2 sigma upper limit on the rate of DPTs in the X-ray region is less than half the rate reported by Dolan (200...

  3. Coherent hard x-rays from attosecond pulse train-assisted harmonic generation

    OpenAIRE

    Klaiber, Michael; Hatsagortsyan, Karen Z.; Müller, Carsten; Christoph H. Keitel

    2007-01-01

    High-order harmonic generation from atomic systems is considered in the crossed fields of a relativistically strong infrared laser and a weak attosecond-pulse train of soft x-rays. Due to one-photon ionization by the x-ray pulse, the ionized electron obtains a starting momentum that compensates the relativistic drift which is induced by the laser magnetic field, and allows the electron to efficiently emit harmonic radiation upon recombination with the atomic core in the relativistic regime. I...

  4. First observation of multi-pulse X-ray train via multi-collision laser Compton scattering

    International Nuclear Information System (INIS)

    A compact hard X-ray source via laser Compton scattering (LCS) has been developed for biological and medical applications at the National Institute of Advanced Industrial Science and Technology (AIST) in Japan. The multi-collision LCS has been investigated in order to enhance the X-ray yields. The first observation of multi-pulse X-ray train with 6 pulses via the multi-collision LCS has been successfully demonstrated between the multi-bunch electron train with 6 bunches and the multi-pulse Ti:Sa laser train with 6 pulses. The 32 MeV electron train was generated from a Cs2Te photocathode rf gun with a multi-pulse UV laser and the S-band linac. The Ti:Sa laser train was obtained with the chirp pulse amplification (CPA) including the modified regenerative amplifier. The X-ray train with 6 pulses with 12.6 ns spacing was observed with the micro-channel plate (MCP). The maximum energy of the X-ray is analytically estimated to be about 24 keV and the total number of generated photons was calculated to be about 1.8x106 photons/train.

  5. UV pulse trains by α-BBO crystal stacking for the production of THz-rap-rate electron bunches

    Science.gov (United States)

    Yan, Li-Xin; Hua, Jian-Fei; Du, Ying-Chao; Huang, Yuan-Fang; You, Yan; Wang, Dan; Huang, Wen-Hui; Tang, Chuan-Xiang; Tang

    2012-08-01

    Ultrashort electron bunch trains can be used for plasma wake field acceleration (PWFA) to overcome the limit of transformer ratio of a single electron bunch, or high-power terahertz (Thz) radiation production by various radiation mechanisms. Basic facility for high-power THz radiation development based on ultrashort electron beam has been set up at accelerator lab of TUB. Using birefringent crystal serials, ultraviolet (UV) pulse shaping for photocathode radio frequency gun to produce THz-repetition-rate pulse train was realized. Driven by such pulses, ultrashort electron bunch train with picosecond (ps) spacing was obtained for THz production. Measurement of the stacked UV pulse trains was done by difference frequency generation (DFG), and the measured group velocity mismatch of α-BBO crystal at 266.7-nm wavelength was 0.8 ps/mm. This method may also be applied to form ramped electron bunch trains for PWFA.

  6. Studies to assess the effect of pet training aids, specifically remote static pulse systems, on the welfare of domestic dogs: field study of dogs in training

    OpenAIRE

    Cooper, Jonathan; Cracknell, Nina; Hardiman, Jessica; Mills, Daniel

    2013-01-01

    The project had a single aim, namely to assess the impact of use of remote static pulse electric training aids (e-collars) during the training of dogs in comparison to dogs referred for similar behavioural problems but without e-collar training. The specific objective was to use appropriate behavioural and physiological measures to make inferences about the welfare of subjects including their aversion and anxiety during and following training. A secondary objective was to evaluate the efficac...

  7. Subwavelength ripples adjustment based on electron dynamics control by using shaped ultrafast laser pulse trains.

    Science.gov (United States)

    Jiang, Lan; Shi, Xuesong; Li, Xin; Yuan, Yanping; Wang, Cong; Lu, Yongfeng

    2012-09-10

    This study reveals that the periods, ablation areas and orientations of periodic surface structures (ripples) in fused silica can be adjusted by using designed femtosecond (fs) laser pulse trains to control transient localized electron dynamics and corresponding material properties. By increasing the pulse delays from 0 to 100 fs, the ripple periods are changed from ~550 nm to ~255 nm and the orientation is rotated by 90°. The nearwavelength/subwavelength ripple periods are close to the fundamental/second-harmonic wavelengths in fused silica respectively. The subsequent subpulse of the train significantly impacts free electron distributions generated by the previous subpulse(s), which might influence the formation mechanism of ripples and the surface morphology.

  8. Effect of two-channel gastric electrical stimulation with trains of pulses on gastric motility

    Institute of Scientific and Technical Information of China (English)

    Bin Yang; Xiao-Hua Hou; Geng-Qing Song; Jin-Song Liu; Jiande DZ Chen

    2009-01-01

    AIM: To investigate the effect of two-channel gastric electrical stimulation (GES) with trains of pulses on gastric emptying and slow waves. METHODS: Seven dogs implanted with four pairs of electrodes and equipped with a duodenal cannula were involved in this study. Two experiments were performed. The first experiment included a series of sessions in the fasting state with trains of short or long pulses, each lasted 10 min. A 5-min recording without pacing was made between two sessions. The second experiment was performed in three sessions (control, single-channel GES, and two-channel GES). The stimulus was applied via the 1st pair of electrodes for single-channel GES (GES via one pair of electrodes located at 14 cm above the pylorus), and simultaneously via the 1st and 3rd channels for two-channel GES (GES via two pairs of electrodes located at 6 and 14 cm above the pylorus). Gastric liquid emptying was collected every 15 min via the cannula for 90 min. RESULTS: GES with trains of pulses at a pulse width of 4 ms or higher was able to entrain gastric slow waves. Two-channel GES was about 50% more efficient than single-channel GES in entraining gastric slow waves. Two channel but not single-channel GES with trains of pulses was capable of accelerating gastric emptying in healthy dogs. Compared with the control session, two-channel GES significantly increased gastric emptying of liquids at 15 min (79.0% ± 6.4% vs 61.3% ± 6.1%, P < 0.01), 30 min (83.2% ± 6.3 % vs 68.2% ± 6.9%, P < 0.01),60 min (86.9% ± 5.5 % vs 74.1% ± 5.9%, P < 0.01),and 90 min (91.0% ± 3.4% vs 76.5% ± 5.9%, P < 0.01).CONCLUSION: Two-channel GES with trains of pulses accelerates gastric emptying in healthy dogs and may have a therapeutic potential for the treatment of gastric motility disorders.

  9. Method to generate a pulse train of few-cycle coherent radiation

    Science.gov (United States)

    Garcia, Bryant; Hemsing, Erik; Raubenheimer, Tor; Campbell, Lawrence T.; McNeil, Brian W. J.

    2016-09-01

    We develop a method to generate a long pulse train of few-cycle coherent radiation by modulating an electron beam with a high power laser. The large energy modulation disperses the beam in a radiating undulator and leads to the production of phase-locked few-cycle coherent radiation pulses. These pulses are produced at a high harmonic of the modulating laser, and are longitudinally separated by the modulating laser wavelength. We discuss an analytical model for this scheme and investigate the temporal and spectral properties of this radiation. This model is compared with numerical simulation results using the unaveraged code Puffin. We examine various harmful effects and how they might be avoided, as well as a possible experimental realization of this scheme.

  10. Gate-controlled generation of optical pulse trains using individual carbon nanotubes

    OpenAIRE

    Jiang, M; Kumamoto, Y.; Ishii, A; Yoshida, M.; Shimada, T; Kato, Y. K.

    2014-01-01

    In single-walled carbon nanotubes, electron–hole pairs form tightly bound excitons because of limited screening. These excitons display a variety of interactions and processes that could be exploited for applications in nanoscale photonics and optoelectronics. Here we report on optical pulse-train generation from individual air-suspended carbon nanotubes under an application of square-wave gate voltages. Electrostatically induced carrier accumulation quenches photoluminescence, while a voltag...

  11. Wide-Range Temperature Sensors with High-Level Pulse Train Output

    Science.gov (United States)

    Hammoud, Ahmad; Patterson, Richard L.

    2009-01-01

    Two types of temperature sensors have been developed for wide-range temperature applications. The two sensors measure temperature in the range of -190 to +200 C and utilize a thin-film platinum RTD (resistance temperature detector) as the temperature-sensing element. Other parts used in the fabrication of these sensors include NPO (negative-positive- zero) type ceramic capacitors for timing, thermally-stable film or wirewound resistors, and high-temperature circuit boards and solder. The first type of temperature sensor is a relaxation oscillator circuit using an SOI (silicon-on-insulator) operational amplifier as a comparator. The output is a pulse train with a period that is roughly proportional to the temperature being measured. The voltage level of the pulse train is high-level, for example 10 V. The high-level output makes the sensor less sensitive to noise or electromagnetic interference. The output can be read by a frequency or period meter and then converted into a temperature reading. The second type of temperature sensor is made up of various types of multivibrator circuits using an SOI type 555 timer and the passive components mentioned above. Three configurations have been developed that were based on the technique of charging and discharging a capacitor through a resistive element to create a train of pulses governed by the capacitor-resistor time constant. Both types of sensors, which operated successfully over the wide temperature range, have potential use in extreme temperature environments including jet engines and space exploration missions.

  12. Self-stabilizing optical clock pulse-train generator using SOA and saturable absorber for asynchronous optical packet processing.

    Science.gov (United States)

    Nakahara, Tatsushi; Takahashi, Ryo

    2013-05-01

    We propose a novel, self-stabilizing optical clock pulse-train generator for processing preamble-free, asynchronous optical packets with variable lengths. The generator is based on an optical loop that includes a semiconductor optical amplifier (SOA) and a high-extinction spin-polarized saturable absorber (SA), with the loop being self-stabilized by balancing out the gain and absorption provided by the SOA and SA, respectively. The optical pulse train is generated by tapping out a small portion of a circulating seed pulse. The convergence of the generated pulse energy is enabled by the loop round-trip gain function that has a negative slope due to gain saturation in the SOA. The amplified spontaneous emission (ASE) of the SOA is effectively suppressed by the SA, and a backward optical pulse launched into the SOA enables overcoming the carrier-recovery speed mismatch between the SOA and SA. Without external control for the loop gain, a stable optical pulse train consisting of more than 50 pulses with low jitter is generated from a single 10-ps seed optical pulse even with a variation of 10 dB in the seed pulse intensity. PMID:23669927

  13. Transient absorption lineshapes in a dense, laser-dressed Helium target probed by attosecond pulse trains

    Science.gov (United States)

    Liao, Chen-Ting; Timmers, Henry; Sandhu, Arvinder

    2014-05-01

    Attosecond transient absorption is an emerging time-resolved spectroscopic technique to explore electron dynamics in atoms and molecules. In this experimental study, we used extreme ultraviolet (XUV) attosecond pulse trains (APTs) in energy range of 20-25 eV to probe the transient excited-state absorption of an optically thick Helium gas sample under the influence of moderately strong (1-3 TW/cm2) , infrared (IR), femtosecond pump pulse. We found that the resonant absorption lineshapes for Helium 1s2p, 1snp, and continuum states show rich dynamics, evolving between Lorenzian and Fano profiles with phases imposed by IR laser pulse and multi-channel quantum-path interference. Both AC Stark shifts and light-induced states were studied as a function of pump-probe delay and IR intensity. By changing the Helium gas density, we observed the lineshape modification due to the macroscopic propagation effects, which is usually not included in the single-atom response model. We found that the 13th and 15th high harmonics of XUV produce two coupled polarizations, and the relative coherence between these two polarizations changes the absorption even when the IR pulse arrives after a long time (about 500 fs) after the XUV. This work is supported by NSF Grant No. PHY-0955274.

  14. Generation of Intense Narrow-Band Tunable Terahertz Radiation from Highly Bunched Electron Pulse Train

    Science.gov (United States)

    Li, Heting; Lu, Yalin; He, Zhigang; Jia, Qika; Wang, Lin

    2016-07-01

    We present the analysis and start-to-end simulation of an intense narrow-band terahertz (THz) source with a broad tuning range of radiation frequency, using a single-pass free electron laser (FEL) driven by a THz-pulse-train photoinjector. The fundamental radiation frequency, corresponding to the spacing between the electron microbunches, can be easily tuned by varying the spacing time between the laser micropulses. Since the prebunched electron beam is highly bunched at the first several harmonics, with the harmonic generation technique, the radiation frequency range can be further enlarged by several times. The start-to-end simulation results show that this FEL is capable of generating a few tens megawatts power, several tens micro-joules pulse energy, and a few percent bandwidth at the frequencies of 0.5-5 THz. In addition, several practical issues are considered.

  15. Effects of pulse current on endurance exercise and its anti-fatigue properties in the hepatic tissue of trained rats.

    Science.gov (United States)

    Chang, Qi; Miao, Xinfang; Ju, Xiaowei; Zhu, Lvgang; Huang, Changlin; Huang, Tao; Zuo, Xincheng; Gao, Chunfang

    2013-01-01

    Fatigue is synonymous with a wide spectrum of familiar physiological conditions, from pathology and general health, to sport and physical exercise. Strenuous, prolonged exercise training causes fatigue. Although several studies have investigated the effects of electrical stimulation frequency on muscle fatigue, the effects of percutaneous pulse current stimulation on fatigue in the hepatic tissue of trained rats is still unclear. In order to find an effective strategy to prevent fatigue or enhance recovery, the effects of pulse current on endurance exercise and its anti-fatigue properties in exercised rats were studied. Rats were subjected to one, three or five weeks of swimming exercise training. After exercise training, rats in the treated group received daily applications of pulse current. All rats were sacrificed after one, three or five weeks of swimming exercise, and the major biochemical indexes were measured in serum and liver. The results demonstrate that pulse current could prolong the exhaustion swimming time, as well as decrease serum ALT, AST and LD levels and liver MDA content. It also elevated serum LDH activity, liver SOD activity and glycogen content. Furthermore, pulse current increased the expression of Bcl-2 and decreased the expression of Bax. Taken together, these results show that pulse current can elevate endurance capacity and facilitate recovery from fatigue. PMID:24116026

  16. Effects of pulse current on endurance exercise and its anti-fatigue properties in the hepatic tissue of trained rats.

    Directory of Open Access Journals (Sweden)

    Qi Chang

    Full Text Available Fatigue is synonymous with a wide spectrum of familiar physiological conditions, from pathology and general health, to sport and physical exercise. Strenuous, prolonged exercise training causes fatigue. Although several studies have investigated the effects of electrical stimulation frequency on muscle fatigue, the effects of percutaneous pulse current stimulation on fatigue in the hepatic tissue of trained rats is still unclear. In order to find an effective strategy to prevent fatigue or enhance recovery, the effects of pulse current on endurance exercise and its anti-fatigue properties in exercised rats were studied. Rats were subjected to one, three or five weeks of swimming exercise training. After exercise training, rats in the treated group received daily applications of pulse current. All rats were sacrificed after one, three or five weeks of swimming exercise, and the major biochemical indexes were measured in serum and liver. The results demonstrate that pulse current could prolong the exhaustion swimming time, as well as decrease serum ALT, AST and LD levels and liver MDA content. It also elevated serum LDH activity, liver SOD activity and glycogen content. Furthermore, pulse current increased the expression of Bcl-2 and decreased the expression of Bax. Taken together, these results show that pulse current can elevate endurance capacity and facilitate recovery from fatigue.

  17. Nonlinear Fourier transformation spectroscopy of small molecules with intense attosecond pulse train

    International Nuclear Information System (INIS)

    We have developed an attosecond nonlinear molecular spectroscopic method called nonlinear Fourier transformation spectroscopy (NFTS) that uses an intense attosecond pulse train (APT) to induce multiphoton ionization processes. In the NFTS method, in addition to characterization of the temporal profile of attosecond pulses, the nonlinear molecular responses are encoded in the interferometric autocorrelation traces depending on the molecular species, their fragment ions and their kinetic energy distributions. The principle and applicability of the NFTS method are described in this paper along with the numerical simulations. The method is applied to diatomic molecules (N2 , D2 and O2) and polyatomic molecules (CO2, CH4 and SF6). Our results highlight the fact that nonlinear spectroscopic information of molecules in the short wavelength region can be obtained through the irradiation of intense APT by taking advantage of the broad spectral bandwidth of attosecond pulses. The development of the nonlinear spectroscopic method in attoseconds is expected to pave the way to investigate the ultrafast intramolecular electron motion such as ultrafast charge migration and electron correlation. (review article)

  18. Effect of treadmill training on peak expiratory flow rate and resting pulse rate among young adult

    Directory of Open Access Journals (Sweden)

    SUKANYA BARDHAN

    2013-01-01

    Full Text Available The present was designed to find out the effect of treadmill training on peak expiratory flow rate and resting pulse rate among young adult boys. The random group design was adopted for this study. Participants were randomly assigned to experimental and control groups. For this purpose, Ten (N = 10 male students of B.A., B.C.A and B.Com from Post Graduate Government College, Sector-11, Chandigarh aged 19-25 years participate in the study. The subjects were being randomly divided into two groups: A (N = 05; Experimental and B (N = 05; Control. Paired "t" test was employed to identify significant differences between the pretest and post-test mean of the two groups through Medical Calculation Version 12.5. To test the hypotheses, the level of significance was set at 0.05. It is concluded that insignificant difference has been found between pre-test and post test (Experimental Group scores of Peak Expiratory Flow Rate (PEFR among young adult boys. No significant difference has been found between the pre-test and post-test(Control Group scores of Peak Expiratory Flow Rate (PEFR among young adult boys. No significant difference has been found between the pre-test and post-test (Experimental Group scores of Resting Pulse Rate among young adult boys. No significant difference has been found between the pre-test and post-test (Control Group scores of Resting Pulse Rate among young adult boys.

  19. Development of ultrasonic pulse-train Doppler method for velocity profile and flowrate measurement

    Science.gov (United States)

    Wada, Sanehiro; Furuichi, Noriyuki; Shimada, Takashi

    2016-11-01

    We present a novel technique for measuring the velocity profile and flowrate in a pipe. This method, named the ultrasonic pulse-train Doppler method (UPTD), has the advantages of expanding the velocity range and setting the smaller measurement volume with low calculation and instrument costs in comparison with the conventional ultrasonic pulse Doppler method. The conventional method has limited measurement of the velocity range due to the Nyquist sampling theorem. In addition, previous reports indicate that a smaller measurement volume increases the accuracy of the measurement. In consideration of the application of the conventional method to actual flow fields, such as industrial facilities and power plants, the issues of velocity range and measurement volume are important. The UPTD algorithm, which exploits two pulses of ultrasound with a short interval and envelope detection, is proposed. Velocity profiles calculated by this algorithm were examined through simulations and excellent agreement was found in all cases. The influence of the signal-to-noise ratio (SNR) on the algorithm was also estimated. The result indicates that UPTD can measure velocity profiles with high accuracy, even under a small SNR. Experimental measurements were conducted and the results were evaluated at the national standard calibration facility of water flowrate in Japan. Every detected signal forms a set of two pulses and the enveloped line can be observed clearly. The results show that UPTD can measure the velocity profiles over the pipe diameter, even if the velocities exceed the measurable velocity range. The measured flowrates were under 0.6% and the standard deviations for all flowrate conditions were within  ±0.38%, which is the uncertainty of the flowrate measurement estimated in the previous report. In conclusion, UPTD provides superior accuracy and expansion of the velocity range.

  20. Coherent lidar modulated with frequency stepped pulse trains for unambiguous high duty cycle range and velocity sensing in the atmosphere

    DEFF Research Database (Denmark)

    Lindelöw, Per Jonas Petter; Mohr, Johan Jacob

    2007-01-01

    Range unambiguous high duty cycle coherent lidars can be constructed based on frequency stepped pulse train modulation, even continuously emitting systems could be envisioned. Such systems are suitable for velocity sensing of dispersed targets, like the atmosphere, at fast acquisition rates....... The lightwave synthesized frequency sweeper is a suitable generator yielding fast pulse repetition rates and stable equidistant frequency steps. Theoretical range resolution profiles of modulated lidars are presented....

  1. Unified parameter for localization in isotope-selective rotational excitation of diatomic molecules using a train of optical pulses

    OpenAIRE

    Matsuoka, Leo

    2015-01-01

    We obtained a simple theoretical unified parameter for the characterization of rotational population propagation of diatomic molecules in a periodic train of resonant optical pulses. The parameter comprises the peak intensity and interval between the pulses, and the level energies of the initial and final rotational states of the molecule. Using the unified parameter, we can predict the upper and lower boundaries of probability localization on the rotational level network, including the effec...

  2. Electric pulse stimulation of cultured murine muscle cells reproduces gene expression changes of trained mouse muscle.

    Directory of Open Access Journals (Sweden)

    Nathalie Burch

    Full Text Available Adequate levels of physical activity are at the center of a healthy lifestyle. However, the molecular mechanisms that mediate the beneficial effects of exercise remain enigmatic. This gap in knowledge is caused by the lack of an amenable experimental model system. Therefore, we optimized electric pulse stimulation of muscle cells to closely recapitulate the plastic changes in gene expression observed in a trained skeletal muscle. The exact experimental conditions were established using the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha as a marker for an endurance-trained muscle fiber. We subsequently compared the changes in the relative expression of metabolic and myofibrillar genes in the muscle cell system with those observed in mouse muscle in vivo following either an acute or repeated bouts of treadmill exercise. Importantly, in electrically stimulated C2C12 mouse muscle cells, the qualitative transcriptional adaptations were almost identical to those in trained muscle, but differ from the acute effects of exercise on muscle gene expression. In addition, significant alterations in the expression of myofibrillar proteins indicate that this stimulation could be used to modulate the fiber-type of muscle cells in culture. Our data thus describe an experimental cell culture model for the study of at least some of the transcriptional aspects of skeletal muscle adaptation to physical activity. This system will be useful for the study of the molecular mechanisms that regulate exercise adaptation in muscle.

  3. Complete population transfer in a three-state quantum system by a train of pairs of coincident pulses

    OpenAIRE

    Rangelov, Andon A.; Vitanov, Nikolay V.

    2012-01-01

    A technique for complete population transfer between the two end states $\\ket{1}$ and $\\ket{3}$ of a three-state quantum system with a train of $N$ pairs of resonant and coincident pump and Stokes pulses is introduced. A simple analytic formula is derived for the ratios of the pulse amplitudes in each pair for which the maximum transient population $P_2(t)$ of the middle state $\\ket{2}$ is minimized, $P_2^{\\max}=\\sin^2(\\pi/4N)$. It is remarkable that, even though the pulses are on exact reson...

  4. Transformation of the frequency-modulated continuous-wave field into a train of short pulses by resonant filters

    CERN Document Server

    Shakhmuratov, R N

    2016-01-01

    The resonant filtering method transforming frequency modulated radiation field into a train of short pulses is proposed to apply in optical domain. Effective frequency modulation can be achieved by electro-optic modulator or by resonant frequency modulation of the filter with a narrow absorption line. Due to frequency modulation narrow-spectrum CW radiation field is seen by the resonant filter as a comb of equidistant spectral components separated by the modulation frequency. Tuning narrow-bandwidth filter in resonance with $n$-th spectral component of the comb transforms the radiation field into bunches of pulses with $n$ pulses in each bunch. The transformation is explained by the interference of the coherently scattered resonant component of the field with the whole comb. Constructive interference results in formation of pulses, while destructive interference is seen as dark windows between pulses. It is found that the optimal thickness of the resonant filter is several orders of magnitude smaller than the...

  5. Complete population transfer in a three-state quantum system by a train of pairs of coincident pulses

    CERN Document Server

    Rangelov, Andon A

    2012-01-01

    A technique for complete population transfer between the two end states $\\ket{1}$ and $\\ket{3}$ of a three-state quantum system with a train of $N$ pairs of resonant and coincident pump and Stokes pulses is introduced. A simple analytic formula is derived for the ratios of the pulse amplitudes in each pair for which the maximum transient population $P_2(t)$ of the middle state $\\ket{2}$ is minimized, $P_2^{\\max}=\\sin^2(\\pi/4N)$. It is remarkable that, even though the pulses are on exact resonance, $P_2(t)$ is damped to negligibly small values even for a small number of pulse pairs. The population dynamics resembles generalized $\\pi$-pulses for small $N$ and stimulated Raman adiabatic passage for large $N$ and therefore this technique can be viewed as a bridge between these well-known techniques.

  6. Optimal control of laser plasma instabilities using Spike Trains of Uneven Duration and Delay (STUD pulses) for ICF and IFE

    Science.gov (United States)

    Afeyan, Bedros; Hüller, Stefan

    2013-11-01

    An adaptive method of controlling parametric instabilities in laser produced plasmas is proposed. It involves fast temporal modulation of a laser pulse on the fastest instability's amplification time scale, adapting to changing and unknown plasma conditions. These pulses are comprised of on and off sequences having at least one or two orders of magnitude contrast between them. Such laser illumination profiles are called STUD pulses for Spike Trains of Uneven Duration and Delay. The STUD pulse program includes scrambling the speckle patterns spatially in between the laser spikes. The off times allow damping of driven waves. The scrambling of the hot spots allows tens of damping times to elapse before hot spot locations experience recurring high intensity spikes. Damping in the meantime will have healed the scars of past growth. Another unique feature of STUD pulses on crossing beams is that their temporal profiles can be interlaced or staggered, and their interactions thus controlled with an on-off switch and a dimmer.

  7. Optimal control of laser plasma instabilities using Spike Trains of Uneven Duration and Delay (STUD pulses) for ICF and IFE

    CERN Document Server

    Afeyan, Bedros

    2012-01-01

    An adaptive method of controlling parametric instabilities in laser produced plasmas is proposed. It involves fast temporal modulation of a laser pulse on the fastest instability's amplification time scale, adapting to changing and unknown plasma conditions. These pulses are comprised of on and off sequences having at least one or two orders of magnitude contrast between them. Such laser illumination profiles are called STUD pulses for Spike Trains of Uneven Duration and Delay. The STUD pulse program includes scrambling the speckle patterns spatially in between the laser spikes. The off times allow damping of driven waves. The scrambling of the hot spots allows tens of damping times to elapse before hot spot locations experience recurring high intensity spikes. Damping in the meantime will have healed the scars of past growth. Another unique feature of STUD pulses on crossing beams is that their temporal profiles can be interlaced or staggered, and their interactions thus controlled with an on-off switch and ...

  8. Ti:sapphire/KrF hybrid laser system generating trains of subterawatt subpicosecond UV pulses

    International Nuclear Information System (INIS)

    The GARPUN-MTW Ti:sapphire/KrF hybrid laser system is used to investigate different multipass schemes for amplifying trains of ultrashort pulses (USPs) of subpicosecond duration. It is shown that, for an USP repetition period of 3 – 5 ns, which exceeds the gain-medium recovery time (∼2 ns), trains are amplified in the same way as single USPs. Due to this, a train can efficiently extract pump energy from the amplifier and sum energies of individual USPs. The energy of a four-USP train, extracted during four passes through the preamplifier and two passes through the final KrF amplifier (4 + 2 scheme), is saturated at a level of 1.6 J and corresponds to maximum USP peak powers of about 0.6 TW. The energy of amplified spontaneous emission (ASE), on the contrary, rapidly increases at a large total gain length Leff ≈ 6 m and is approximately equal to the USP energy. In the (4 + 1) and (2 + 2) schemes the USP energy decreases only slightly, to Eout = 1.3 and 1.2 J, and the ASE fraction is reduced to about 10% and 3%, respectively. USP self-focusing leads to multiple laser beam filamentation and a 200-fold local increase in the radiation intensity in filaments, to ∼2 × 1011 W cm-2, a level at which the nonlinear loss in the output CaF2 windows of the KrF amplifier, caused by three-photon absorption, nonlinear scattering, and broadening of the radiation spectrum to a value exceeding the gain band of the KrF laser transition, becomes the main factor determining the saturation of the USP output energy. (lasers)

  9. The pulsed linear induction motor concept for high-speed trains

    Energy Technology Data Exchange (ETDEWEB)

    Turman, B.N.; Marder, B.M.; Rohwein, G.J.; Aeschliman, D.P.; Kelley, J.B.; Cowan, M.; Zimmerman, R.M.

    1995-06-01

    The SERAPBIM (SEgmented RAil PHased Induction Motor) concept is a linear induction motor concept which uses rapidly-pulsed magnetic fields and a segmented reaction rail, as opposed to low-frequency fields and continuous reaction rails found in conventional linear induction motors. These improvements give a high-traction, compact, and efficient linear motor that has potential for advanced high speed rail propulsion. In the SERAPBIM concept, coils on the vehicle push against a segmented aluminum rail, which is mounted on the road bed. Current is pulsed as the coils cross an edge of the segmented rail, inducing surface currents which repel the coil. The coils must be pulsed in synchronization with the movement by reaction rail segments. This is provided by a sense-and-fire circuit that controls the pulsing of the power modulators. Experiments were conducted to demonstrate the feasibility of the pulsed induction motor and to collect data that could be used for scaling calculations. A 14.4 kg aluminum plate was accelerated down a 4 m track to speeds of over 15 m/sec with peak thrust up to 18 kN per coilset. For a trainset capable of 200 mph speed, the SERAPHIM concept design is based on coils which are each capable of producing up to 3.5 kN thrust, and 30 coil pairs are mounted on each power car. Two power cars, one at each end of the train, provide 6 MW from two gas turbine prime power units. The thrust is about 210.000 N and is essentially constant up to 200 km/hr since wheel slippage does not limit thrust as with conventional wheeled propulsion. A key component of the SERAPHIM concept is the use of passive wheel-on-rah support for the high speed vehicle. Standard steel wheels are capable of handling over 200 mph. The SERAPHIM cost is comparable to that for steel-wheel high-speed rail, and about 10% to 25% of the projected costs for a comparable Maglev system.

  10. Studies of dark resonances in Rb atoms in the field of light pulse train

    International Nuclear Information System (INIS)

    Dark resonances in 87Rb vapor in the field of a femtosecond laser pulse train have been studied theoretically and experimentally. Three- and four-level schemes of interaction between an 87Rb atom and the field, which are formed by the field-coupled magnetic sublevels of states 2S1=2 and 3P3=2 of the rubidium atom have been analyzed. The position and the shape of the experimentally recorded dark resonance correspond to the results of our calculations. It has been shown that the interaction between rubidium vapor and a polychromatic field allows the signal to be enhanced substantially in comparison with that in the case of bichromatic field.

  11. Quantum path control using attosecond pulse trains via UV-assisted resonance enhance ionization

    Institute of Scientific and Technical Information of China (English)

    李芳; 魏来; 何志聪

    2015-01-01

    We theoretically investigate the quantum path selection in an ultraviolet (UV)-assisted near-infrared field with an UV energy below the ionization threshold. By calculating the ionization probability with different assistant UV frequencies, we find that a resonance-enhanced ionization peak emerges in the region Euvpulse train (APT) centered in the resonance region, we show that the short quantum path can be well selected in the continuum case. By performing the electron trajectory analysis, we have further explained the physical mechanism of the quantum path selection. Moreover, we also demonstrate that in the resonance region, the harmonic emission from the selected paths is more efficient than that with the APT energy above the ionization threshold.

  12. Studies to assess the effect of pet training aids specifically remote static pulse systems on the welfare of domestic dogs

    OpenAIRE

    Cooper, Jonathan; Wright, Hannah; Mills, Daniel; Casey, Rachel; Blackwell, Emily; Van Driel, Katja; Lines, Jeff

    2013-01-01

    This project assessed the welfare of dogs trained with pet training aids, specifically remote static pulse collar systems (e-collars). Previous work has focused on a very limited number of devices in a very limited range of contexts and the evidence of the impact of such devices on dog's overall quality of life is inconclusive. Project AW1402 aimed to assess the physical characteristics of the e-collars and the physiological, behavioural and psychological consequences of their use in dog trai...

  13. Effects of Pulse Current on Endurance Exercise and Its Anti-Fatigue Properties in the Hepatic Tissue of Trained Rats

    OpenAIRE

    Qi Chang; Xinfang Miao; Xiaowei Ju; Lvgang Zhu; Changlin Huang; Tao Huang; Xincheng Zuo; Chunfang Gao

    2013-01-01

    Fatigue is synonymous with a wide spectrum of familiar physiological conditions, from pathology and general health, to sport and physical exercise. Strenuous, prolonged exercise training causes fatigue. Although several studies have investigated the effects of electrical stimulation frequency on muscle fatigue, the effects of percutaneous pulse current stimulation on fatigue in the hepatic tissue of trained rats is still unclear. In order to find an effective strategy to prevent fatigue or en...

  14. Two-photon double ionization of neon using an intense attosecond pulse train

    CERN Document Server

    Manschwetus, B; Campi, F; Maclot, S; Coudert-Alteirac, H; Lahl, J; Wikmark, H; Rudawski, P; Heyl, C M; Farkas, B; Mohamed, T; L'Huillier, A; Johnsson, P

    2016-01-01

    We present the first demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1 $\\mu$J, a central energy of 35 eV and a total bandwidth of $\\sim30$ eV. The APT is focused by broadband optics in a neon gas target to an intensity of $3\\cdot10^{12} $W$\\cdot$cm$^{-2}$. By tuning the photon energy across the threshold for the sequential process the double ionization signal can be turned on and off, indicating that the two-photon double ionization predominantly occurs through a sequential process. The demonstrated performance opens up possibilities for future XUV-XUV pump-probe experiments with attosecond temporal resolution in a photon energy range where it is possible to unravel the dynamics behind direct vs. sequential double ionization and the asso...

  15. EXponentially Converging Eradication Pulse Train (EXCEPT) for solvent-signal suppression in investigations with variable T1 times

    Science.gov (United States)

    Satterfield, Emmalou T.; Pfaff, Annalise R.; Zhang, Wenjia; Chi, Lingyu; Gerald, Rex E.; Woelk, Klaus

    2016-07-01

    Selective presaturation is a common technique for suppressing excessive solvent signals during proton NMR analysis of dilute samples in protic solvents. When the solvent T1 relaxation time constant varies within a series of samples, parameters for the presaturation sequence must often be re-adjusted for each sample. The EXCEPT (EXponentially Converging Eradication Pulse Train) presaturation pulse sequence was developed to eliminate time consuming pulse-parameter re-optimization as long as the variation in the solvent's T1 remains within an order of magnitude. EXCEPT consists of frequency-selective inversion pulses with progressively decreasing interpulse delays. The interpulse delays were optimized to encompass T1 relaxation times ranging from 1 to 10 s, but they can be easily adjusted by a single factor for other ranges that fall within an order of magnitude with respect to T1. Sequences with different numbers of inversion pulses were tested to maximize suppression while minimizing the number of pulses and thus the total time needed for suppression. The EXCEPT-16 experiment, where 16 denotes the number of inversion pulses, was found satisfactory for many standard applications. Experimental results demonstrate that EXCEPT provides effective T1-insensitive solvent suppression as predicted by the theory. The robustness of EXCEPT with respect to changes in solvent T1 allows NMR investigations to be carried out for a series of samples without the need for pulse-parameter re-optimization for each sample.

  16. EXponentially Converging Eradication Pulse Train (EXCEPT) for solvent-signal suppression in investigations with variable T1 times.

    Science.gov (United States)

    Satterfield, Emmalou T; Pfaff, Annalise R; Zhang, Wenjia; Chi, Lingyu; Gerald, Rex E; Woelk, Klaus

    2016-07-01

    Selective presaturation is a common technique for suppressing excessive solvent signals during proton NMR analysis of dilute samples in protic solvents. When the solvent T1 relaxation time constant varies within a series of samples, parameters for the presaturation sequence must often be re-adjusted for each sample. The EXCEPT (EXponentially Converging Eradication Pulse Train) presaturation pulse sequence was developed to eliminate time consuming pulse-parameter re-optimization as long as the variation in the solvent's T1 remains within an order of magnitude. EXCEPT consists of frequency-selective inversion pulses with progressively decreasing interpulse delays. The interpulse delays were optimized to encompass T1 relaxation times ranging from 1 to 10s, but they can be easily adjusted by a single factor for other ranges that fall within an order of magnitude with respect to T1. Sequences with different numbers of inversion pulses were tested to maximize suppression while minimizing the number of pulses and thus the total time needed for suppression. The EXCEPT-16 experiment, where 16 denotes the number of inversion pulses, was found satisfactory for many standard applications. Experimental results demonstrate that EXCEPT provides effective T1-insensitive solvent suppression as predicted by the theory. The robustness of EXCEPT with respect to changes in solvent T1 allows NMR investigations to be carried out for a series of samples without the need for pulse-parameter re-optimization for each sample. PMID:27179454

  17. Propagation of two short laser pulse trains in a $\\Lambda$-type three-level medium under conditions of electromagnetically induced transparency

    CERN Document Server

    Buica, Gabriela

    2014-01-01

    We investigate the dynamics of a pair of short laser pulse trains propagating in a medium consisting of three-level $\\Lambda$-type atoms by numerically solving the Maxwell-Schr\\"odinger equations for atoms and fields. By performing propagation calculations with different parameters, under conditions of electromagnetically induced transparency, we compare the propagation dynamics by a single pair of probe and coupling laser pulses and by probe and coupling laser pulse trains. We discuss the influence of the coupling pulse area, number of pulses, and detunings on the probe laser propagation and realization of electromagnetically induced transparency conditions, as well on the formation of a dark state.

  18. Influence of aerobic exercise training on post-exercise responses of aortic pulse pressure and augmentation pressure in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Nobuhiko eAkazawa

    2015-10-01

    Full Text Available Central arterial blood pressure (BP is more predictive of future cardiovascular events than is brachial BP because it reflects the BP load imposed on the left ventricle with greater accuracy. However, little is known about the effects of exercise training on central hemodynamic response to acute exercise. The purpose of the present study was to determine the influence of an aerobic exercise regimen on the response of aortic BP after a single aerobic exercise in postmenopausal women. Nine healthy postmenopausal women (age: 61 ± 2 years participated in a 12-week aerobic exercise training regimen. Before and after the training, each subjects performed a single bout of cycling at ventilatory thresholds for 30 min. We evaluated the post-exercise aortic BP response, which was estimated via the general transfer function from applanation tonometry. After the initial pre-training aerobic exercise session, aortic BP did not change significantly: however, aortic pulse pressure and augmentation pressure were significantly attenuated after the single aerobic exercise session following the 12-week training regimen. The present study demonstrated that a regular aerobic exercise training regimen induced the post-exercise reduction of aortic pulse pressure and augmentation pressure. Regular aerobic exercise training may enhance post-exercise reduction in aortic BP.

  19. Generation of tailored pulse trains for efficient material processing by a high power MOPA system with birefringence compensation

    International Nuclear Information System (INIS)

    A flash lamp pumped, acousto-optical Q-switched Nd:YAG master oscillator power amplifier (MOPA) system with an average output power of almost 150 W and a beam quality of M2 < 2.5 is developed. The system operates with a 100 Hz repetition rate for the flash lamps. In each pumping pulse a pulse train of 5 to 40 Q-switched laser pulses is generated. The pulse length is from 25 to 150 ns. A high beam quality of the amplified beam is realized by an elaborate amplifier design and a careful alignment of the beam diameter to the amplifier rods. Additionally, the thermally induced birefringence of the amplifiers is compensated by a 90° rotator and an optical image-relay system between two identical amplifier rods, so that a linear polarized laser beam could be achieved with depolarization losses below 2%

  20. Probing with randomly interleaved pulse train bridges the gap between ultrafast pump-probe and nanosecond flash photolysis.

    Science.gov (United States)

    Nakagawa, Tatsuo; Okamoto, Kido; Hanada, Hiroaki; Katoh, Ryuzi

    2016-04-01

    Despite the long-standing importance of transient absorption (TA) spectroscopy, many researchers remain frustrated by the difficulty of measuring the nanosecond range in a wide spectral range. To address this shortcoming, we propose a TA spectrophotometer in which there is no synchronization between a pump pulse and a train of multiple probe pulses from a picosecond supercontinuum light source, termed the randomly-interleaved-pulse-train (RIPT) method. For each pump pulse, many monochromatized probe pulses impinge upon the sample, and the associated pump-probe time delays are determined passively shot by shot with subnanosecond accuracy. By repeatedly pumping with automatically varying time delays, a TA temporal profile that covers a wide dynamic range from subnanosecond to milliseconds is simultaneously obtained. By scanning wavelength, this single, simple apparatus acquires not only wide time range TA profiles, but also broadband TA spectra from the visible through the near-infrared regions. Furthermore, we present a typical result to demonstrate how the RIPT method may be used to correct for fluorescence, which often pollutes TA curves. PMID:27192271

  1. Crater geometry characterization of Al targets irradiated by single pulse and pulse trains of Nd:YAG laser in ambient air and water

    International Nuclear Information System (INIS)

    High intensities laser pulses are capable to generate a crater when irradiating metal targets. In such condition, after each irradiation significant ablation occurs on the target surface and as a result a crater is formed. The crater characterization is very important specifically for some applications such as micromachining. In this paper, the crater formation in metal targets was studied experimentally. The planar aluminum 5052 targets were irradiated by frequency doubled (532 nm), Q-switched Nd:YAG (∼6 ns) laser beam in ambient air and distilled water. A crater was produced after each irradiation and it was characterized by an optical microscope. Different laser intensities as well as pulse trains were applied for crater formation. The effects of laser characteristics in crater geometry were examined. The depth of the craters was measured by optical microscope and the diameter (width) was characterized by processing of the crater image. The results were explained in terms of ablation threshold and plasma shielding. The results show that the crater geometry extremely depends on the laser pulse intensity, the number of laser pulses, and ambient.

  2. Optimal Control of Laser-Plasma Instabilities Using Spike Trains of Uneven Duration and Delay: STUD Pulses

    CERN Document Server

    Afeyan, Bedros

    2013-01-01

    Adaptive methods of laser irradiation of plasmas are proposed consisting of deterministic, `on-off' amplitude modulations in time, and intermittently changing speckle-patterns. These laser pulses consist of a series of picosecond time-scale spikes in a spike train of uneven duration and delay (STUD pulses), in contrast to hydrodynamic-time-scale modulated, multi-nanosecond pulses for laser fusion. Properly designed STUD pulses minimize backscatter and tame any absorptive parametric instability for a given set of plasma conditions, by adjusting the modulation periods, duty cycles and spatial hot-spot-distribution scrambling-rates of the spikes. Traditional methods of beam conditioning are subsumed or surpassed by STUD pulses. In addition, STUD pulses allow an advance in the control of instabilities driven by spatially overlapped laser beams by allowing the spikes of crossing beams to be temporally staggered. When the intensity peaks of one fall within the nulls of its crossing beam, it allows an on-off switch ...

  3. The Study on the Variation of the Cavity Length's Influence on the Output Pulse Train of the Actively Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    LUO Hong-e; TIAN Xiao-jian; GAO Bo

    2005-01-01

    The influence of actively mode-locked Erbium-Doped Fiber Laser(EDFL) cavity length variation on the noises of an optical pulse train is investigated, in theory and in MATLAB simulation. Using a simple model, the noise characteristics of the output pulse train are studied. The results show that the noises of the output pulse train increase with the increasing of the variation of the cavity length. The theory analysis and the simulation results agree well. This result is very significant for us to improve the reliability and the stability of the actively mode-locked fiber laser.

  4. Optical limiting and dynamical two-photon absorption of porphyrin with ruthenium outlying complexes for a picosecond pulse train

    Science.gov (United States)

    Zhang, Yu-Jin; Sun, Yu-Ping; Wang, Chuan-Kui

    2016-01-01

    Propagation and nonlinear optical absorption of a picosecond pulse train in strong reverse saturable absorption (RSA) materials (free-based tetrapyridyl porphyrin H2TPyP with ruthenium (Ru) outlying complexes) are investigated by solving coupled rate equations and field intensity equation. Influence of outlying Ru groups on optical limiting (OL) properties is studied. Propagation of the front subpulses is mainly affected by linear transition between the ground state and the first excited singlet state, while intensity of the latter subpulses is attenuated by the excited state absorption (ESA). These two different absorption mechanisms result in asymmetric distribution of the transmitted pulse. It is shown that effective population transfer time from the ground state to the lowest triplet state and RSA play important roles in the OL performance and pulse shaping. Moreover, our results indicate that the porphyrins studied are ideal optical limiters because of their large ESA cross section and long lifetime of the lowest triplet state. Compounds with the presence of Ru group possess preferable power limiting ability. Ligand group attached to Ru also influences the nonlinear optical absorption of compounds. Special attention has been paid on dynamical two-photon absorption (TPA) cross section which depends crucially on the duration of the subpulse as well as time interval between subpulses. The present study provides a way to modulate nonlinear optical absorption properties of the medium by changing parameters of the pulse train.

  5. Optimal control of laser plasma instabilities using Spike Trains of Uneven Duration and Delay (STUD pulses) for ICF and IFE

    International Nuclear Information System (INIS)

    An adaptive method of controlling parametric instabilities in laser produced plasmas is proposed. It involves fast temporal modulation of a laser pulse on the fastest instability's amplification time scale, adapting to changing and unknown plasma conditions. These pulses are comprised of on and off sequences having at least one or two orders of magnitude contrast between them. Such laser illumination profiles are called STUD pulses for Spike Trains of Uneven Duration and Delay. The STUD pulse program includes scrambling the speckle patterns spatially in between the laser spikes. The off times allow damping of driven waves. The scrambling of the hot spots allows tens of damping times to elapse before hot spot locations experience recurring high intensity spikes. Damping in the meantime will have healed the scars of past growth. Another unique feature of STUD pulses on crossing beams is that their temporal profiles can be interlaced or staggered, and their interactions thus controlled with an on-off switch and a dimmer. (authors)

  6. Gigahertz repetition rate, sub-femtosecond timing jitter optical pulse train directly generated from a mode-locked Yb:KYW laser

    CERN Document Server

    Yang, Heewon; Shin, Junho; Kim, Chur; Choi, Sun Young; Kim, Guang-Hoon; Rotermund, Fabian; Kim, Jungwon

    2014-01-01

    We show that a 1.13-GHz repetition rate optical pulse train with 0.70 fs high-frequency timing jitter (integration bandwidth of 17.5 kHz - 10 MHz, where the measurement instrument-limited noise floor contributes 0.41 fs in 10 MHz bandwidth) can be directly generated from a free-running, single-mode diode-pumped Yb:KYW laser mode-locked by single-walled carbon nanotube (SWCNT)-coated mirrors. To our knowledge, this is the lowest timing jitter optical pulse train with the GHz repetition rate ever measured. If this pulse train is used for direct sampling of 565-MHz signals (Nyquist frequency of the pulse train), the demonstrated jitter level corresponds to the projected effective-number-of-bit (ENOB) of 17.8, which is much higher than the thermal noise limit of 50-ohm load resistance (~14 bits).

  7. A NEW TECHNIQUE OF MEASURING LOW‐POWER PICOSECOND OPTICAL PULSE TRAINS

    OpenAIRE

    Muñoz Zurita, Ana Luz; Shcherbakov, Alexandre S.; Campos Acosta, Joaquín; Gómez Jiménez, Ramón

    2009-01-01

    We present a theoretic approach to the characterization of low‐power bright ultrashort optical pulses with an internal frequency modulation simultaneously in both time and frequency domains. The analysis and computer simulations are applied to studying the capability of Wigner distribution to characterize solitary pulses in practically important case of the sech‐pulses. Then, the simplest two‐beam scanning Michelson interferometer is selected for shaping the field‐strength auto‐correlation fu...

  8. All-optical, transform-limited and high mark-space-ratio soliton pulse train generation using both CDPF ad NOLM

    DEFF Research Database (Denmark)

    Yujun, Qian; Povlsen, Jørn Hedegård; Varming, Poul

    1999-01-01

    Soliton pulse generation from optical beat signal by both CDPF andNOLM is proposed. A transform-limited soliton train with mark-space-ratio(MSR) higher than 1:40 can be obtained at multiples of 10GHz.......Soliton pulse generation from optical beat signal by both CDPF andNOLM is proposed. A transform-limited soliton train with mark-space-ratio(MSR) higher than 1:40 can be obtained at multiples of 10GHz....

  9. PWM调制脉冲序列控制Boost变换器%PWM Modulated Pulse Train Control for Boost Converter

    Institute of Scientific and Technical Information of China (English)

    高玉; 许建平; 秦明; 兰燕妮

    2011-01-01

    提出了开关变换器的PWM调制脉冲序列(Pulse Width Modulated Pulse Train,简称PWM-PT)控制方法.PWM-PT控制通过将开关变换器输出电压与参考电压进行比较,产生PWM调制信号,并根据调制信号的电平相应地选择高功率控制脉冲或低功率控制脉冲实现变换器的控制.以电感电流断续工作模式Boost变换器为例,分析了PWM-PT控制技术的工作原理.分析和实验结果验证了PWM-PT控制的可行性和PWM-PT控制开关变换器优越的瞬态特性.%Pulse width modulated-pulse train(PWM-PT) control method applied to the control of switching mode converter is presented.The error between output voltage and reference voltage of the converter is used to generate the low frequency modulation signal, from which the high or low power control pulse is chosen by PWM-PT controller to achieve the control of the converter. Boost converter in DCM is used as an example to illustrate the operation principle of PWM-PT control technique.The analysis and experimental results verify the feasibility and advantage of PWMPT control technique with better transient response characteristics.

  10. Comparison of RABITT and FROG measurements in the temporal characterization of attosecond pulse trains

    CERN Document Server

    Kim, Kyung Taec; Park, Mi Na; Imran, Tayyab; Umesh, G; Nam, Chang Hee

    2007-01-01

    The attosecond high harmonic pulses obtained from a long Ar-filled gas cell were characterized by two techniques - the reconstruction of attosecond beating by interference of two-photon transition (RABITT) and frequency-resolved optical gating (FROG) methods. The pulse durations obtained by RABITT and FROG methods agreed within 10 %.

  11. A bright attosecond x-ray pulse train generation in a double-laser-driven cone target

    Science.gov (United States)

    Hu, Li-Xiang; Yu, Tong-Pu; Shao, Fu-Qiu; Luo, Wen; Yin, Yan

    2016-06-01

    By using full three-dimensional particle-in-cell and Monte Carlo simulations, we investigate the generation of a high-brightness attosecond x-ray pulse train in a double-laser-driven cone target. The scheme makes use of two lasers: the first high-intensity laser with a laser peak intensity 1.37 × 1020 W/cm2 irradiates the cone and produces overdense attosecond electron bunches; the second counterpropagating weakly relativistic laser with a laser peak intensity 4.932 × 1017 W/cm2 interacts with the produced electron bunches and a bright x-ray pulse train is generated by Thomson backscattering of the second laser off the attosecond electron bunches. It is shown that the photon flux rises by 5 times using the cone target as compared with a normal channel. Meanwhile, the x-ray peak brightness increases significantly from 1.4 × 1021/(s mm2 mrad2 0.1 keV) to 6.0 × 1021/(s mm2 mrad2 0.1 keV), which is much higher than that of the Thomson x-ray source generated from traditional accelerators. We also discuss the influence of the laser and target parameters on the x-ray pulse properties. This compact bright x-ray source may have diverse applications, e.g., the study of electric dynamics and harmonics emission in the atomic scale.

  12. Temporal Shaping of High Peak Power Pulse Trains from a Burst-Mode Laser System

    OpenAIRE

    Jörg Körner; Jürgen Reiter; Joachim Hein; Kaluza, Malte C.

    2015-01-01

    It has been shown in the past that pulsed laser systems operating in the so-called “burst mode” are a beneficial approach to generate high peak power laser pulses at high repetition rates suitable for various applications. So far, most high-energy burst-mode laser systems put great effort into generating a homogeneous energy distribution across the burst duration, e.g., by shaping the pump pulse. In this work, we present a new shaping technique, which is able to produce arbitrary energy distr...

  13. The density broadening in a sodium F=2 condensate detected by a pulse train

    Directory of Open Access Journals (Sweden)

    Jianing Han

    2011-09-01

    Full Text Available The dipole-blockaded sodium clock transition has been detected by high resolution microwave spectroscopy, the multiple-pulse spectroscopy. This spectroscopic technique has been first used to detect the density broadening and shifting in a Sodium Bose Einstein Condensate (BEC by probing the sodium clock-transition. Moreover, by narrowing the pulse-width of the pulses, some of the broadening mechanisms can be partially reduced. The results reported here are essential steps toward the ground-state quantum computing, few-body spectroscopy, spin squeezing and quantum metrology.

  14. Theory of Pulse Train Amplification Without Patterning Effects in Quantum Dot Semiconductor Optical Amplifiers

    DEFF Research Database (Denmark)

    Uskov, Alexander V.; Berg, Tommy Winther; Mørk, Jesper

    2004-01-01

    A theory for pulse amplification and saturation in quantum dot (QD) semiconductor optical amplifiers (SOAs) is developed. In particular, the maximum bit rate at which a data stream of pulses can be amplified without significant patterning effects is investigated. Simple expressions are derived...... that clearly show the dependence of the maximum bit rate on material and device parameters. A comparative analysis of QD, quantum well (QW), and bulk SOAs shows that QD SOAs may have superior properties; calculations predict patterning-free amplification up to bit rates of 150–200 Gb/s with pulse output...

  15. HyperCEST detection of cucurbit[6]uril in whole blood using an ultrashort saturation Pre-pulse train.

    Science.gov (United States)

    Hane, Francis T; Smylie, Peter S; Li, Tao; Ruberto, Julia; Dowhos, Krista; Ball, Iain; Tomanek, Boguslaw; DeBoef, Brenton; Albert, Mitchell S

    2016-07-01

    Xenon based biosensors have the potential to detect and localize biomarkers associated with a wide variety of diseases. The development and nuclear magnetic resonance (NMR) characterization of cage molecules which encapsulate hyperpolarized xenon is imperative for the development of these xenon biosensors. We acquired (129) Xe NMR spectra, and magnetic resonance images and a HyperCEST saturation map of cucurbit[6]uril (CB6) in whole bovine blood. We observed a mean HyperCEST depletion of 84% (n = 5) at a concentration of 5 mM and 74% at 2.5 mM. Additionally, we collected these data using a pulsed HyperCEST saturation pre-pulse train with a SAR of 0.025 W/kg which will minimize any potential RF heating in animal or human tissue. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27071809

  16. Attosecond timing jitter pulse trains from semiconductor saturable absorber mode-locked Cr:LiSAF lasers

    OpenAIRE

    Sennaroğlu, Alphan; Li, Duo; Demirbaş, Ümit; Benedick, Andrew; Fujimoto, James G.; Kaertner, Franz X.

    2012-01-01

    The timing jitter of optical pulse trains from diode-pumped, semiconductor saturable absorber mode-locked femtosecond Cr:LiSAF lasers is characterized by a single-crystal balanced optical cross-correlator with an equivalent sensitivity in phase noise of -235 dBc/Hz. The RMS timing jitter is 30 attoseconds integrated from 10 kHz to 50 MHz, the Nyquist frequency of the 100 MHz repetition rate oscillator. The AM-to-PM conversion induced excess phase noise is calculated and compared with experime...

  17. Effects of picosecond terawatt UV laser beam filamentation and a repetitive pulse train on creation of prolonged plasma channels in atmospheric air

    International Nuclear Information System (INIS)

    Amplitude-modulated UV laser pulse of up to 30 J energy was produced at hybrid Ti:Sapphire/KrF GARPUN-MTW laser facility when a preliminary amplified train of short pulses was injected into unstable resonator cavity of the main e-beam-pumped KrF amplifier. The combined radiation consisted of regeneratively amplified picosecond pulses with subTW peak power overlapped with 100-ns pulse of a free-running lasing. The advantages of combined radiation for production of long-lived prolonged plasma channels in air and HV discharge triggering were demonstrated: photocurrent sustained by modulated pulse is two orders of magnitude higher and HV breakdown distance is twice longer than for a smooth UV pulse. It was found that in contrast to IR radiation multiple filamentation of high-power UV laser beam does not produce extended nonlinear focusing of UV radiation

  18. A new coding concept for fast ultrasound imaging using pulse trains

    DEFF Research Database (Denmark)

    Misaridis, T.; Jensen, Jørgen Arendt

    2002-01-01

    Frame rate in ultrasound imaging can he increased by simultaneous transmission of multiple beams using coded waveforms. However, the achievable degree of orthogonality among coded waveforms is limited in ultrasound, and the image quality degrades unacceptably due to interbeam interference....... In this paper, an alternative combined time-space coding approach is undertaken. In the new method all transducer elements are excited with short pulses and the high time-bandwidth (TB) product waveforms are generated acoustically. Each element transmits a short pulse spherical wave with a constant transmit...

  19. Shaping SHF train of optical picosecond pulses for generating a photoemission in SHF guns

    International Nuclear Information System (INIS)

    The paper analyses a technique of generating optical picosecond pulses (OPP) through laser beam deflection. The OPP generator consists of a laser, deflection system, optical system and amplifier-converter. The technique of OPP generation through laser beam deflection can be successfully used for triggering photoemission in SHF beams. 8 refs., 2 figs

  20. Generation of 10 GHz, 1.9 ps optical pulse train using semiconductor optical amplifier and silica-based highly nonlinear fiber

    International Nuclear Information System (INIS)

    We propose a simple approach to generate a high quality 10 GHz 1.9 ps optical pulse train using a semiconductor optical amplifier and silica-based highly nonlinear fiber. An optical pulse generator based on our proposed scheme is easy to set up with commercially available optical components. A 10 GHz, 1.9 ps optical pulse train is obtained with timing jitter as low as 60 fs over the frequency range 10 Hz–1 MHz. With a wavelength tunable CW laser, a wide wavelength tunable span can be achieved over the entire C band. The proposed optical pulse generator also can operate at different repetition rates from 3 to 10 GHz

  1. Molecular orientation via a dynamically induced pulse-train: Wave packet dynamics of NaI in a static electric field

    DEFF Research Database (Denmark)

    Marquetand, P.; Materny, A.; Henriksen, Niels Engholm;

    2004-01-01

    the charge separation is present, i.e., when the bond-length is large, a strong dipole moment exists and rotational excitation takes place. Upon bond contraction, the then covalently bound molecule does not experience the external field. This scenario repeats itself periodically. Thus, the vibrational...... dynamics causes a situation which is comparable to the interaction of the molecule with a train of pulses where the pulse separation is determined by the vibrational period. (C) 2004 American Institute of Physics....

  2. Cavity-enhanced single frequency synthesis via DFG of mode-locked pulse trains

    OpenAIRE

    Ferrari, Gabriele; Carusotto, Iacopo

    2005-01-01

    We show how to synthesize a CW, single-frequency optical field from the frequency-dispersed, pulsed field of a mode-locked laser. This process, which relies on difference frequency generation in an optical cavity, is efficient and can be considered as an optical rectification. Quantitative estimates for the output power and amplitude noise properties of a realistic system are given. Possible applications to optical frequency synthesis and optical metrology are envisaged.

  3. Safety training and safe operating procedures written for PBFA (Particle Beam Fusion Accelerator) II and applicable to other pulsed power facilities

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, G.L.; Goldstein, S.A.

    1986-12-01

    To ensure that work in advancing pulsed power technology is performed with an acceptably low risk, pulsed power research facilities at Sandia National Laboratories must satisfy general safety guidelines established by the Department of Energy, policies and formats of the Environment, Safety, and Health (ES and H) Department, and detailed procedures formulated by the Pulsed Power Sciences Directorate. The approach to safety training and to writing safe operating procedures, and the procedures presented here are specific to the Particle Beam Fusion Accelerator II (PBFA II) Facility but are applicable as guidelines to other research and development facilities which have similar hazards.

  4. Safety training and safe operating procedures written for PBFA [Particle Beam Fusion Accelerator] II and applicable to other pulsed power facilities

    International Nuclear Information System (INIS)

    To ensure that work in advancing pulsed power technology is performed with an acceptably low risk, pulsed power research facilities at Sandia National Laboratories must satisfy general safety guidelines established by the Department of Energy, policies and formats of the Environment, Safety, and Health (ES and H) Department, and detailed procedures formulated by the Pulsed Power Sciences Directorate. The approach to safety training and to writing safe operating procedures, and the procedures presented here are specific to the Particle Beam Fusion Accelerator II (PBFA II) Facility but are applicable as guidelines to other research and development facilities which have similar hazards

  5. Taking the Pulse of Training Transfer: Instructor Quality and EMT Certification Examination Results

    Science.gov (United States)

    Russ-Eft, Darlene F.; Dickison, Phil; Levine, Roger

    2010-01-01

    The Longitudinal Emergency Medical Technician Attributes and Demographics Study (LEADS) provides a representative sampling of EMTs throughout the United States. The present study adds to the transfer of training literature by examining the relationship between instructor quality and National Registry of Emergency Medical Technicians certification…

  6. IMPACT OF SHORT TERM TRAINING OF ANULOM VILOM PRANAYAM ON BLOOD PRESSURE AND PULSE RATE IN HEALTHY VOLUNTEERS

    Directory of Open Access Journals (Sweden)

    Dandekar Pradnya Deepak

    2013-04-01

    Full Text Available In present scenario, Yoga is becoming most popular science due to its positive effect on health. To achieve preventive, curative and rehabilitative aspects of health, Yoga draws the attention of large group of people. Prana (energy and Ayam (to expand or control form the word Pranayam. Pranayam is a technique to control or expand the energy in body. Practice of Pranayam has been known to modulate cardiac autonomic status with an improvement in cardio-respiratory functions. Keeping this in view, the present study designed to determine whether Anulom- Vilom Pranayam followed by Shawasan has immediate effect on pulse rate, systolic and diastolic blood pressure. Thirty normal healthy subjects aged between 17-20 years, volunteered for this study. All the selected physiological parameters were measured before and after performing ‘Anulom – Vilom Pranayama’ followed by Shawasan for four weeks. Experimental group showed a significant decline in Systolic Blood Pressure (p<0.021. On other hand there was no significant change in Diastolic Blood Pressure and pulse rate, though it showed slight decrease. Our study indicates that, short-term training of ‘Anulom- Vilom Pranayam ‘shows significant decrease in Systolic Blood Pressure. Control of breathing process to make it deep and prolong by doing alternate nostril breathing with slow and rhythmic manner brings about balance in autonomous nervous system. In addition, practice of Anulom- Vilom pranayama for short-term duration could get better parasympathetic control over the heart.

  7. Control of Stimulated Raman Scattering in the Strongly Nonlinear and Kinetic Regime Using Spike Trains of Uneven Duration and Delay: STUD Pulses

    CERN Document Server

    Albright, B J; Afeyan, B

    2013-01-01

    Stimulated Raman scattering (SRS) in its strongly nonlinear, kinetic regime is controlled by a technique of deterministic, strong temporal modulation and spatial scrambling of laser speckle patterns, called Spike Trains of Uneven Duration and Delay (STUD pulses) [B. Afeyan and S. H\\"uller, Phys. Rev. Lett. (submitted)]. Kinetic simulations show that use of STUD pulses may decrease SRS reflectivity by more than an order of magnitude over random-phase-plate (RPP) or induced-spatial-incoherence (ISI) beams of the same average intensity and comparable bandwidth.

  8. High-precision Distribution of Highly-stable Optical Pulse Trains with Sub-10-fs Timing Jitter

    CERN Document Server

    Ning, B; Hou, D; Wu, J T; Li, Z B; Zhao, J Y

    2014-01-01

    High-precision optical pulse trains distribution via fibre links has made huge impacts in many fields. In most published works, the accuracies are still fundamentally limited by some unavoidable noises, such as thermal and shot noise from conventional photodiodes, thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system by using highly-precision phase detector to overcome the limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors to realize optical-electrical conversion and phase measurements, for suppressing the noises and achieving ultra-high accuracy. A 10-km fibre link distribution experiment shows our system provides a residual instability at the level of 4.6*10-15@1-s and 6.1*10-18@10000-s, with an integrated timing jitter as low as 3.8 fs in a bandwidth of 1 Hz to 100 KHz. This low instability and timing jitter makes it possible that our system can be used in the optical clock distri...

  9. Evolutions of Continuous-Wave Perturbed by Pulse and Generation of Ultra-Short Pulse Trains%脉冲扰动下连续波的演化及超短脉冲串产生

    Institute of Scientific and Technical Information of China (English)

    钟先琼; 向安平; 程科; 蔡青

    2011-01-01

    Based on the nonlinear Schr(o)dinger equation and the stepped Fourier method, the shape and spectrum evolutions of continuous-wave perturbed by an optical pulse with Gaussian-typed continuum spectrum in an optical fiber are numerically simulated. The results show that, due to modulation instability in the anomalous dispersion region of the optical fiber, this pulse perturbed continuous-wave can also evolve into high-repetition-rate pulse trains, which is similar to the case of sine perturbed one. Being different from the latter case, however, the generated pulses are not equal to each other in terms of widths, intensities, and intervals. When soliton parameters are too small or the optical wave is in the normal dispersion region, only attenuation oscillation structures instead of pulse trains can be generated. And the characteristics of pulse trains or oscillation structures will vary with the soliton parameters. These evolution characteristics are obviously different from those of conventional sine perturbed continuous-waves and Gaussian optical pulses.%从光纤中非线性薛定谔方程出发,采用分步傅里叶算法数值模拟了具有高斯型连续谱的光脉冲扰动下连续波在光纤中的波形和频谱演化.结果表明,在光纤负色散区,由于调制不稳定性,该脉冲扰动下的连续波也可能像正弦波扰动下的那样演化成高重复率超短脉冲串,但构成脉冲串的各脉冲并不像正弦波扰动时那样等宽、等高、等间距.当孤子参数太小或在正色散区时,则不能形成脉冲串,只能形成衰减的振荡结构.随着孤子参数的不同,超短脉冲串及振荡结构的特点也会不同.这些演化规律与传统正弦光扰动连续波及高斯光脉冲的情形明显不同.

  10. Attosecond control of orbital parity mix interferences and the relative phase of even and odd harmonics in an attosecond pulse train.

    Science.gov (United States)

    Laurent, G; Cao, W; Li, H; Wang, Z; Ben-Itzhak, I; Cocke, C L

    2012-08-24

    We experimentally demonstrate that atomic orbital parity mix interferences can be temporally controlled on an attosecond time scale. Electron wave packets are formed by ionizing argon gas with a comb of odd and even high-order harmonics, in the presence of a weak infrared field. Consequently, a mix of energy-degenerate even and odd parity states is fed in the continuum by one- and two-photon transitions. These interfere, leading to an asymmetric electron emission along the polarization vector. The direction of the emission can be controlled by varying the time delay between the comb and infrared field pulses. We show that such asymmetric emission provides information on the relative phase of consecutive odd and even order harmonics in the attosecond pulse train. PMID:23002742

  11. Bandwidth and repetition rate programmable Nyquist sinc-shaped pulse train source based on intensity modulators and four-wave mixing.

    Science.gov (United States)

    Cordette, S; Vedadi, A; Shoaie, M A; Brès, C-S

    2014-12-01

    We propose and experimentally demonstrate an all-optical Nyquist sinc-shaped pulse train source based on intensity modulation and four-wave mixing. The proposed scheme allows for the tunability of the bandwidth and the full flexibility of the repetition rate in the limit of the electronic bandwidth of the modulators used through the flexible synthesis of rectangular frequency combs. Bandwidth up to 360 GHz at 40 GHz rate and up to 45 frequency lines at 5 GHz rate are demonstrated with 40 GHz modulators.

  12. Methods of Optimal Control of Laser-Plasma Instabilities Using Spike Trains of Uneven Duration and Delay (STUD Pulses)

    Science.gov (United States)

    Afeyan, Bedros

    2013-10-01

    We have recently introduced and extensively studied a new adaptive method of LPI control. It promises to extend the effectiveness of laser as inertial fusion drivers by allowing active control of stimulated Raman and Brillouin scattering and crossed beam energy transfer. It breaks multi-nanosecond pulses into a series of picosecond (ps) time scale spikes with comparable gaps in between. The height and width of each spike as well as their separations are optimization parameters. In addition, the spatial speckle patterns are changed after a number of successive spikes as needed (from every spike to never). The combination of these parameters allows the taming of parametric instabilities to conform to any desired reduced reflectivity profile, within the bounds of the performance limitations of the lasers. Instead of pulse shaping on hydrodynamical time scales, far faster (from 1 ps to 10 ps) modulations of the laser profile will be needed to implement the STUD pulse program for full LPI control. We will show theoretical and computational evidence for the effectiveness of the STUD pulse program to control LPI. The physics of why STUD pulses work and how optimization can be implemented efficiently using statistical nonlinear optical models and techniques will be explained. We will also discuss a novel diagnostic system employing STUD pulses that will allow the boosted measurement of velocity distribution function slopes on a ps time scale in the small crossing volume of a pump and a probe beam. Various regimes from weak to strong coupling and weak to strong damping will be treated. Novel pulse modulation schemes and diagnostic tools based on time-lenses used in both microscope and telescope modes will be suggested for the execution of the STUD pule program. Work Supported by the DOE NNSA-OFES Joint Program on HEDLP and DOE OFES SBIR Phase I Grants.

  13. Pulse!!: a model for research and development of virtual-reality learning in military medical education and training.

    Science.gov (United States)

    Dunne, James R; McDonald, Claudia L

    2010-07-01

    Pulse!! The Virtual Clinical Learning Lab at Texas A&M University-Corpus Christi, in collaboration with the United States Navy, has developed a model for research and technological development that they believe is an essential element in the future of military and civilian medical education. The Pulse!! project models a strategy for providing cross-disciplinary expertise and resources to educational, governmental, and business entities challenged with meeting looming health care crises. It includes a three-dimensional virtual learning platform that provides unlimited, repeatable, immersive clinical experiences without risk to patients, and is available anywhere there is a computer. Pulse!! utilizes expertise in the fields of medicine, medical education, computer science, software engineering, physics, computer animation, art, and architecture. Lab scientists collaborate with the commercial virtual-reality simulation industry to produce research-based learning platforms based on cutting-edge computer technology. PMID:23634475

  14. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete

    2012-01-01

    Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...

  15. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas

    2012-01-01

    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  16. Electroporation adopting trains of biphasic pulses enhances in vitro and in vivo the cytotoxic effect of doxorubicin on multidrug resistant colon adenocarcinoma cells (LoVo).

    Science.gov (United States)

    Meschini, Stefania; Condello, Maria; Lista, Pasquale; Vincenzi, Bruno; Baldi, Alfonso; Citro, Gennaro; Arancia, Giuseppe; Spugnini, Enrico P

    2012-09-01

    Few articles in the literature have focused on electroporation as a strategy to reverse multidrug resistance (MDR) of tumour cells and they are mostly limited to the improved efficacy of bleomycin. We tested the application of trains of biphasic pulses to cell suspensions and to murine xenografts as a strategy to increase the uptake of doxorubicin (DOX) and to enhance its cytotoxicity against chemoresistant cells. The human colon adenocarcinoma cell line LoVo DX, expressing MDR phenotype with high levels of P-glycoprotein (P-gp), has been used. The in vitro and in vivo studies gave the following results: (i) the application of the electric pulses to the cell suspension, immediately before DOX administration, induced a significant increase of drug retention; (ii) confocal microscopy observations showed a remarkable increase of intranuclear accumulation of DOX induced by electroporation; (iii) cell survival assay revealed a decrease of cell viability in the cultures treated with the combination of electroporation and doxorubicin; (iv) scanning electron microscopy observations revealed consistent morphological changes after the combined exposure to electroporation and doxorubicin; (v) in implanted mice the combined treatment induced an evident slowdown on the tumour growth when compared to treatment with DOX alone; (vi) histopathological analysis evidenced tumour destruction and its replacement by scar tissue in the tumours treated with the combination of doxorubicin and electroporation.

  17. Study on Control Pulse Combination and Output Voltage Ripple of Pulse Train Controlled DCM Boost Converter%脉冲序列控制DCM Boost变换器的控制脉冲组合和输出电压纹波研究

    Institute of Scientific and Technical Information of China (English)

    吴志敏; 包伯成; 张希

    2013-01-01

      深入研究了工作于电感电流断续导电模式(discontinuous conduction mode,DCM)的脉冲序列控制Boost变换器,在分析每个开关周期内高、低功率脉冲控制下输出电压变化量的基础上,研究了不同负载下脉冲序列控制DCM Boost变换器在一个功率脉冲循环周期内高、低功率控制脉冲组合方式和输出电压纹波,为脉冲序列控制方案的设计提供了必要的依据。基于PSIM电路仿真,得到了不同负载时的时域波形,仿真结果验证了控制脉冲组合方式、纹波分析结果的正确性及控制方案的可行性。本文的分析方法和研究结论对脉冲序列控制开关变换器的设计和运行具有重要的指导意义。%This paper explores pulse train controlled boost converter operating in discontinuous conduction mode (DCM). By analyzing the output voltage variations under the high and low power pulse controls in each switching cycle, the paper also investigates the high and low power control pulse combinations and output voltage ripples in a power pulse train repetition cycle of pulse train controlled DCM boost converter with different loads are investigated, which provide the necessary basis for the design of pulse train control scheme. By using PSIM circuit simulations, the time-domain waveforms under different loads are obtained. Simulation results verify the correctness of the control pulse combinations and ripple analysis results and the feasibility of the proposed control scheme. The analysis methods and research results in this paper possess important guiding significance in the design and operation of pulse train controlled switching converters.

  18. Chaotic carrier pulse position modulation communication system and method

    Science.gov (United States)

    Abarbanel, Henry D. I.; Larson, Lawrence E.; Rulkov, Nikolai F.; Sushchik, Mikhail M.; Tsimring, Lev S.; Volkovskii, Alexander R.

    2001-01-01

    A chaotic carrier pulse position modulation communication system and method is disclosed. The system includes a transmitter and receiver having matched chaotic pulse regenerators. The chaotic pulse regenerator in the receiver produces a synchronized replica of a chaotic pulse train generated by the regenerator in the transmitter. The pulse train from the transmitter can therefore act as a carrier signal. Data is encoded by the transmitter through selectively altering the interpulse timing between pulses in the chaotic pulse train. The altered pulse train is transmitted as a pulse signal. The receiver can detect whether a particular interpulse interval in the pulse signal has been altered by reference to the synchronized replica it generates, and can therefore detect the data transmitted by the receiver. Preferably, the receiver predicts the earliest moment in time it can expect a next pulse after observation of at least two consecutive pulses. It then decodes the pulse signal beginning at a short time before expected arrival of a pulse.

  19. Compact pulse repetition rate multiplication scheme using micro ring resonator

    DEFF Research Database (Denmark)

    Ji, Hua; Pu, Minhao; Galili, Michael;

    2009-01-01

    A compact repetition rate multiplier using a micro ring resonator is experimentally demonstrated. Combined with an amplitude equalizer, a 40 GHz pulse train is achieved from a 10 GHz input pulse train.......A compact repetition rate multiplier using a micro ring resonator is experimentally demonstrated. Combined with an amplitude equalizer, a 40 GHz pulse train is achieved from a 10 GHz input pulse train....

  20. The coherent artifact in modern pulse measurements

    CERN Document Server

    Ratner, Justin; Wong, Tsz Chun; Bartels, Randy; Trebino, Rick

    2012-01-01

    We simulate multi-shot intensity-and-phase measurements of unstable ultrashort-pulse trains using frequency-resolved-optical-gating (FROG) and spectral phase interferometry for direct electric-field reconstruction (SPIDER). Both techniques fail to reveal the pulse structure. FROG yields the average pulse duration and suggests the instability by exhibiting disagreement between measured and retrieved traces. SPIDER under-estimates the average pulse duration but retrieves the correct average pulse spectral phase. An analytical calculation confirms this behavior.

  1. Digital Communication Using Chaotic Pulse Generators

    CERN Document Server

    Rulkov, N F; Tsimring, L S; Volkovskii, A R; Abarbanel, Henry D I; Larson, L; Yao, K

    1999-01-01

    Utilization of chaotic signals for covert communications remains a very promising practical application. Multiple studies indicated that the major shortcoming of recently proposed chaos-based communication schemes is their susceptibility to noise and distortions in communication channels. In this talk we discuss a new approach to communication with chaotic signals, which demonstrates good performance in the presence of channel distortions. This communication scheme is based upon chaotic signals in the form of pulse trains where intervals between the pulses are determined by chaotic dynamics of a pulse generator. The pulse train with chaotic interpulse intervals is used as a carrier. Binary information is modulated onto this carrier by the pulse position modulation method, such that each pulse is either left unchanged or delayed by a certain time, depending on whether ``0'' or ``1'' is transmitted. By synchronizing the receiver to the chaotic pulse train we can anticipate the timing of pulses corresponding to ...

  2. Dynamic parabolic pulse generation using temporal shaping of wavelength to time mapped pulses.

    Science.gov (United States)

    Nguyen, Dat; Piracha, Mohammad Umar; Mandridis, Dimitrios; Delfyett, Peter J

    2011-06-20

    Self-phase modulation in fiber amplifiers can significantly degrade the quality of compressed pulses in chirped pulse amplification systems. Parabolic pulses with linear frequency chirp are suitable for suppressing nonlinearities, and to achieve high peak power pulses after compression. In this paper, we present an active time domain technique to generate parabolic pulses for chirped pulse amplification applications. Pulses from a mode-locked laser are temporally stretched and launched into an amplitude modulator, where the drive voltage is designed using the spectral shape of the input pulse and the transfer function of the modulator, resulting in the generation of parabolic pulses. Experimental results of pulse shaping with a pulse train from a mode-locked laser are presented, with a residual error of less than 5%. Moreover, an extinction ratio of 27 dB is achieved, which is ideal for chirped pulse amplification applications.

  3. Time shift of pulses due to dispersion slope and nonlinearity

    Energy Technology Data Exchange (ETDEWEB)

    Marcuse, D.; Menyuk, C.R.; Holzloehner, R.

    1999-12-01

    The authors show that the time delay of optical pulses traveling in long fibers is influenced by the dispersion slope and the fiber nonlinearity. Consequently, one or more new pulses that are inserted by add-drop operations into a pulse train that has already traveled a long distance may shift relative to the old pulses. This time shift delays the initial pulses more than the newly inserted ones, so that the newly inserted pulses can leave their time frames, leading to errors.

  4. High-speed pulse-shape generator, pulse multiplexer

    Science.gov (United States)

    Burkhart, Scott C.

    2002-01-01

    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  5. 五阶非线性光纤中连续谱相位扰动下的光传输与脉冲串产生%Propagation of Optical Wave with Phase Perturbed by Continuous Spectrum and Generation of Pulse Trains in Optical Fibers with Quintic Nonlinearity

    Institute of Scientific and Technical Information of China (English)

    钟先琼; 向安平; 程科

    2011-01-01

    According to the extended nonlinear Schr(o)dinger equation including quintic nonlinearity in optical fibers,modulation instability (MI) based generation of high-repetition-rate optical pulse trains is numerically demonstrated by using the optical wave with its phase perturbed by Gaussian-typed continuous spectrum instead of conventional monochromatic one. The results show that,the pulse trains can also be generated due to MI effect like the conventional case.However,being different from the conventional case,the generated pulse trains here consist of limited number of pulses which are generally not equal in width,intensity,and interval.And the pulse number increases with the propagation distance.Moreover,when the other parameters are the same,the positive quintic nonlinearity can make the pulse width and interval shorten,which means that the positive quintic nonlinearity is beneficial to generate higher repetition rate pulse trains.While the negative one takes the opposite.The numerically calculated chirps developed during the generation process of pulse trains indicate that,both the chirps and their variations with the distance are highly nonmonotonic,and the quintic nonlinearity will change both the chirp range and the chirp amount.%根据包含五阶非线性的扩展非线性薛定谔方程,数值研究了高斯型连续谱相位扰动而不是传统单色扰动下基于调制不稳定性的高重复率脉冲串产生.结果表明:脉冲串也能像传统情形那样形成,但却呈现出不同的特性.如脉冲数目有限,且各脉冲的高度、强度及间距不等.脉冲数目随传输距离增加而增加.而五阶非线性能使脉冲宽度和间距变小因而有利于高重复率脉冲串产生,负五阶非线性则相反.对脉冲串形成过程中演变啁啾的数值计算表明,啁啾及其随距离的变化都是高度非单调的,五阶非线性将改变啁啾的范围和量值.

  6. Pulse Voltammetry.

    Science.gov (United States)

    Osteryoung, Janet

    1983-01-01

    Discusses the nature of pulse voltammetry, indicating that its widespread use arises from good sensitivity and detection limits and from ease of application and low cost. Provides analytical and mechanistic applications of the procedure. (JN)

  7. Robot-assisted gait training improves brachial–ankle pulse wave velocity and peak aerobic capacity in subacute stroke patients with totally dependent ambulation

    Science.gov (United States)

    Han, Eun Young; Im, Sang Hee; Kim, Bo Ryun; Seo, Min Ji; Kim, Myeong Ok

    2016-01-01

    Abstract Objective: Brachial–ankle pulse wave velocity (baPWV) evaluates arterial stiffness and also predicts early outcome in stroke patients. The objectives of this study were to investigate arterial stiffness of subacute nonfunctional ambulatory stroke patients and to compare the effects of robot-assisted gait therapy (RAGT) combined with rehabilitation therapy (RT) on arterial stiffness and functional recovery with those of RT alone. Method: The RAGT group (N = 30) received 30 minutes of robot-assisted gait therapy and 30 minutes of conventional RT, and the control group (N = 26) received 60 minutes of RT, 5 times a week for 4 weeks. baPWV was measured and calculated using an automated device. The patients also performed a symptom-limited graded exercise stress test using a bicycle ergometer, and parameters of cardiopulmonary fitness were recorded. Clinical outcome measures were categorized into 4 categories: activities of daily living, balance, ambulatory function, and paretic leg motor function and were evaluated before and after the 4-week intervention. Results: Both groups exhibited significant functional recovery in all clinical outcome measures after the 4-week intervention. However, peak aerobic capacity, peak heart rate, exercise tolerance test duration, and baPWV improved only in the RAGT group, and the improvements in baPWV and peak aerobic capacity were more noticeable in the RAGT group than in the control group. Conclusion: Robot-assisted gait therapy combined with conventional rehabilitation therapy represents an effective method for reversing arterial stiffness and improving peak aerobic capacity in subacute stroke patients with totally dependent ambulation. However, further large-scale studies with longer term follow-up periods are warranted to measure the effects of RAGT on secondary prevention after stroke. PMID:27741123

  8. Computationally intelligent pulsed photoacoustics

    International Nuclear Information System (INIS)

    In this paper, the application of computational intelligence in pulsed photoacoustics is discussed. Feedforward multilayer perception networks are applied for real-time simultaneous determination of the laser beam spatial profile and vibrational-to-translational relaxation time of the polyatomic molecules in gases. Networks are trained and tested with theoretical data adjusted for a given experimental set-up. Genetic optimization has been used for calculation of the same parameters, fitting the photoacoustic signals with a different number of generations. Observed benefits from the application of computational intelligence in pulsed photoacoustics and advantages over previously developed methods are discussed, such as real-time operation, high precision and the possibility of finding solutions in a wide range of parameters, similar to in experimental conditions. In addition, the applicability for practical uses, such as the real-time in situ measurements of atmospheric pollutants, along with possible further developments of obtained results, is argued. (paper)

  9. Attosecond pulse shaping using partial phase matching

    International Nuclear Information System (INIS)

    We propose a method for programmable shaping of the amplitude and phase of the extreme ultraviolet and x-ray attosecond pulses produced by high-order harmonic generation. It overcomes the bandwidth limitations of existing spectral filters and enables removal of the intrinsic attosecond chirp as well as the synthesis of pulse sequences. It is based on partial phase matching using a longitudinally addressable modulation. Although the method is in principle applicable to any form of partial phase matching, we focus on quasi-phase matching using a counterpropagating pulse train. We present simulations of the production of isolated attosecond pulses at 250 eV, including a 31 as transform-limited pulse, tunably chirped pulses and double pulses. (paper)

  10. Laser pulse shaping for high gradient accelerators

    Science.gov (United States)

    Villa, F.; Anania, M. P.; Bellaveglia, M.; Bisesto, F.; Chiadroni, E.; Cianchi, A.; Curcio, A.; Galletti, M.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Gatti, G.; Moreno, M.; Petrarca, M.; Pompili, R.; Vaccarezza, C.

    2016-09-01

    In many high gradient accelerator schemes, i.e. with plasma or dielectric wakefield induced by particles, many electron pulses are required to drive the acceleration of one of them. Those electron bunches, that generally should have very short duration and low emittance, can be generated in photoinjectors driven by a train of laser pulses coming inside the same RF bucket. We present the system used to shape and characterize the laser pulses used in multibunch operations at Sparc_lab. Our system gives us control over the main parameter useful to produce a train of up to five high brightness bunches with tailored intensity and time distribution.

  11. Isotope-selective ionization using four-pulse alignment

    International Nuclear Information System (INIS)

    We have proposed a laser isotope separation method utilizing molecular alignment and non-resonant multiphoton ionization, and demonstrated isotope-selective ionization of 14N2 and 15N2 isotopomers, using one-pulse alignment. In the present work, we used a train of four identical pulses, instead of one pulse, to obtain the higher selectivity. (author)

  12. Single X-Ray Attosecond Pulse Generation by Using Combined Pulses Irradiating on a United Two-Atom System

    Institute of Scientific and Technical Information of China (English)

    CHEN Ji-Gen; LI Chen; CHI Fang-Ping; YANG Yu-Jun

    2007-01-01

    @@ A scheme of a single x-ray attosecond pulse generation from a two-atom system exposed to the combined laser pulses is proposed. Our numerical results show that a single x-ray attosecond pulse rather than a train one can be produced by modulation of ionization.

  13. Training safely, Training safety

    OpenAIRE

    Jianjun Wu; An, M.; Jin, Y.; H. Geng

    2014-01-01

    It is the basic requirement of maritime safety education to guarantee the safety of teaching operation while training the crew's occupation safety capability. Marine Training Center of Shanghai Maritime University has undertaken the practical teaching of "marine survival" for many years and come up with the whole safety procedures of training. Based on the requirements of SOLAS convention and regulations of STCW over crew training, this paper introduces the safety allocation, utilization and ...

  14. Method for pulse to pulse dose reproducibility applied to electron linear accelerators

    International Nuclear Information System (INIS)

    An original method for obtaining programmed beam single shots and pulse trains with programmed pulse number, pulse repetition frequency, pulse duration and pulse dose is presented. It is particularly useful for automatic control of absorbed dose rate level, irradiation process control as well as in pulse radiolysis studies, single pulse dose measurement or for research experiments where pulse-to-pulse dose reproducibility is required. This method is applied to the electron linear accelerators, ALIN-10 of 6.23 MeV and 82 W and ALID-7, of 5.5 MeV and 670 W, built in NILPRP. In order to implement this method, the accelerator triggering system (ATS) consists of two branches: the gun branch and the magnetron branch. ATS, which synchronizes all the system units, delivers trigger pulses at a programmed repetition rate (up to 250 pulses/s) to the gun (80 kV, 10 A and 4 ms) and magnetron (45 kV, 100 A, and 4 ms).The accelerated electron beam existence is determined by the electron gun and magnetron pulses overlapping. The method consists in controlling the overlapping of pulses in order to deliver the beam in the desired sequence. This control is implemented by a discrete pulse position modulation of gun and/or magnetron pulses. The instabilities of the gun and magnetron transient regimes are avoided by operating the accelerator with no accelerated beam for a certain time. At the operator 'beam start' command, the ATS controls electron gun and magnetron pulses overlapping and the linac beam is generated. The pulse-to-pulse absorbed dose variation is thus considerably reduced. Programmed absorbed dose, irradiation time, beam pulse number or other external events may interrupt the coincidence between the gun and magnetron pulses. Slow absorbed dose variation is compensated by the control of the pulse duration and repetition frequency. Two methods are reported in the electron linear accelerators' development for obtaining the pulse to pulse dose reproducibility: the method

  15. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  16. Changes of blood pressure,pulse rate and respiratory rate in submariners following simulated air-breathing 3-50 m fast buoyancy ascent escape training%模拟3~50 m快速上浮脱险训练潜艇艇员血压、脉率和呼吸频率的变化

    Institute of Scientific and Technical Information of China (English)

    姚健; 顾秀良; 方以群; 张和翔; 陈锐勇; 孟淼; 袁恒荣; 王世锋; 马骏; 王海涛

    2010-01-01

    目的 观察模拟快速上浮脱险训练时潜艇艇员生命指征的变化.方法 分别进行了3、10、30、50 m 4个深度69人次的快速上浮脱险训练,于训练前、训练后即刻及出舱后10 min分别测定艇员的血压、脉率和呼吸频率.结果 训练后即刻艇员的收缩压、舒张压、脉率及呼吸频率与进舱前比较,绝大部分指标有所增加,差异有统计学意义(P<0.01).在出舱后10 min各指标基本恢复正常.结论 模拟快速上浮脱险训练可增加艇员血压、脉率和呼吸频率,但均为一过性.本次脱险训练方案是安全可靠的.%Objective To observe effects of simulated air-breathing fast buoyancy ascent escape training on the vital signs of submariners.Methods A series of escape training,totaling 69 man-times were carried out at different depths of 3,10,30 and 50 m.Blood pressure,pulse rate and respiratory rate of the submariners were measured before training.the moment after termination of training and 10 min after surfacing from the escape chamber.Results When compared with those of pre-training,most of the indices concerning systolic pressure,diastolic pressure,pulse rate and respiratory rate of the submariners increased quite significantly,with statistical differences (P<0.01) the moment after termination of training.Nevertheless,the values almost returned to normal,10 minutes after training.Conclusions Simulated air-breathing fast buoyancy ascent could elevate blood pressure,pulse rate and respiratory rate of submariners.However,these changes were all transient.The profile of our submarine escape training proves to be safe and reliable.

  17. Pulse radiolysis

    International Nuclear Information System (INIS)

    This supplement to two bibliographies published in 1970 and 1972 lists 734 references to the literature of pulse radiolysis, arranged under eight broad subject headings. The references were compiled by searching Biological Abstracts, Chemical Abstracts, Nuclear Science Abstracts and the Weekly List of Papers in Radiation Chemistry issued by the Radiation Chemistry Data Center of Notre Dame University. Full bibliographic data is given for papers published in the period 1971 to 1974. A personal author index listing more than 600 authors and a similar number of co-authors is included

  18. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  19. Zeptosecond $\\gamma$-ray pulses

    CERN Document Server

    Klaiber, Michael; Keitel, Christoph H

    2007-01-01

    High-order harmonic generation (HHG) in the relativistic regime is employed to obtain zeptosecond pulses of $\\gamma$-rays. The harmonics are generated from atomic systems in counterpropagating strong attosecond laser pulse trains of linear polarization. In this setup recollisions of the ionized electrons can be achieved in the highly relativistic regime via a reversal of the commonly deteriorating drift and without instability of the electron dynamics such as in a standing laser wave. As a result, coherent attosecond $\\gamma$-rays in the 10 MeV energy range as well as coherent zeptosecond $\\gamma$-ray pulses of MeV photon energy for time-resolved nuclear spectroscopy become feasible.

  20. Language Training: English Training

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Language Training Françoise Benz tel. 73127 language.training@cern.ch General and Professional English Courses The next session will take place: from 1st March to 25 June 2004 (2 weeks break at Easter). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957.

  1. Language Training: English Training

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. LANGUAGE TRAINING Françoise Benz tel. 73127 language.training@cern.ch General and Professional English Courses The next session will take place: from 1st March to 25 June 2004 (2 weeks break at Easter). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957.

  2. Short (~ ns) single pulse FIR (70-500 µm) multi-kW Raman conversion, of a short pulse (~ 25ns) broadband CO2 Laser

    OpenAIRE

    Marchetti, S; Bartalini, S.; Simili, R.; Martinelli, M

    1994-01-01

    In this work a summary of many pulse compressed (< 10ns), FIR, high power, Raman emissions produced by a short pulse (25 ns) broadband (2GHz) CO2 laser is shown. Generally it has been always possible to obtain a single pulse (≈ ns) conversion from a pulse train of a self -mode locked CO2, also if it is not really reproducible. These emissions are interesting in pulsed high field EPR experiments.

  3. Directly driven source of multi-gigahertz, sub-picosecond optical pulses

    Energy Technology Data Exchange (ETDEWEB)

    Messerly, Michael J.; Dawson, Jay W.; Barty, Christopher P.J.; Gibson, David J.; Prantil, Matthew A.; Cormier, Eric

    2015-10-20

    A robust, compact optical pulse train source is described, with the capability of generating sub-picosecond micro-pulse sequences, which can be periodic as well as non-periodic, and at repetition rates tunable over decades of baseline frequencies, from MHz to multi-GHz regimes. The micro-pulses can be precisely controlled and formatted to be in the range of many ps in duration to as short as several fs in duration. The system output can be comprised of a continuous wave train of optical micro-pulses or can be programmed to provide gated bursts of macro-pulses, with each macro-pulse consisting of a specific number of micro-pulses or a single pulse picked from the higher frequency train at a repetition rate lower than the baseline frequency. These pulses could then be amplified in energy anywhere from the nJ to MJ range.

  4. Buck Switching Mode Power Supply Based on Pulse-Train Control Technique Applied to a DC-DC Step-down Power Supply%基于脉冲序列控制技术的降压型开关电源

    Institute of Scientific and Technical Information of China (English)

    侯鑫尧; 倪强

    2011-01-01

    Base on analyzing the principle and working process of pulse-train(PT) control technique,a simple and practical PT controller is designed.PSpice Simulation results of PT controlled buck converter in discontinuous conduction mode(DCM) are performed in this%在分析开关电源脉冲序列(Pulse Train,PT)控制方法的原理和工作过程的基础上,设计了一种简单实用的脉冲序列控制电路。利用PSpice对PT控制DCM Buck变换器进行了仿真研究,并通过实验验证了脉冲序列控制器的可行性和正确性,为PT控制开关电源提供了一种有效的实施方案。

  5. Excimer Laser Pulse Compress With Pulse Feedback

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>To attain a shorter laser pulse, a compressing technique called pulse feedback was developed from the saturation gain switch applied to the amplification in a discharge pumping excimer laser cavity. It can

  6. Optimal laser pulse energy partitioning for air ionization

    CERN Document Server

    Schubert, Elise; Matthews, Mary; Courjaud, Antoine; Kasparian, Jérôme; Wolf, Jean-Pierre

    2016-01-01

    We investigate the pulse partitioning of a 6.3 mJ, 450 fs pulse at 1030 nm to produce plasma channels. At such moderate energies, splitting the energy into several sub-pulses reduces the ionization efficiency and thus does not extend the plasma lifetime. We numerically show that when sufficient energy to produce multifilamentation is available, splitting the pulse temporally in a pulse train increases the gas temperature compared to a filament bundle of the same energy. This could improve the mean free path of the free electrons, therefore enhancing the efficiency of discharge triggering.

  7. LIU 0.5/3000 pulse-periodical linear induction accelerator

    International Nuclear Information System (INIS)

    LIU 0.5/3000 accelerator designed for production of accelerator nanosecond high-current electron beam is described. Its main characteriatics are as follows: electron beam energy in pulse is 50j; electron peak energy - 500 keV; beam pulse power - 15 GW; current amplitude in pulse - 3 kA; beam current duration - 80 ns (at 0.1 level); beam aperture - 8-30cm2; accelerator operates in three modes: single-pulse mode, continuous mode with 50 pulses/s. Succession frequency, mode of pulse train formationfrom 5-10 pulses with equivalent pulse duration in the train up to 200 pulses/s; operating lifetime is ≥ 107 pulses. Accelerator dimensions are 2000x2100x900 mm, its mass - 800 kg

  8. Complex pulsing schemes for high frame rate imaging

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Fink, Mathias; Jensen, Jørgen Arendt

    2002-01-01

    High frame rate ultrasound imaging can be achieved by simultaneous transmission of multiple focused beams along different directions. However, image quality degrades by the interference among beams. An alternative approach is to transmit spherical waves of a basic short pulse with frequency coding...... up to a pulse train. The acoustically generated high time-bandwidth (TB) product waveforms can be compressed by using a filter bank of matched filters one for every beam direction. Matched filtering compresses the pulse train to a single pulse at the scatterer position plus a number of spike axial......B. With the proposed imaging strategy of pulse train excitation, a whole image can be formed with only two emissions, making it possible to obtain high quality images at a frame rate of 20 to 25 times higher than that of conventional phased array imaging...

  9. Language training: French training

    CERN Multimedia

    Françoise Benz

    2005-01-01

    General and Professional French Courses The next session will take place from 30 January to 07 April 2006. These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz : Tel. 73127. Writing Professional Documents in French The next session will take place from 30 January to 07 April 2006. This course is designed for people with a good level of spoken French. Duration: 30 hours Price: 660 CHF (for 8 students) For further information and registration, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz : Tel. 73127. FORMATION EN LANGUES LANGUAGE TRAINING Françoise Benz 73127 language.training@cern.ch

  10. Language Training: French Training

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. LANGUAGE TRAINING Françoise Benz tel. 73127 language.training@cern.ch General and Professional French Courses The next session will take place from 26 April to 02 July 2004. These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: Tel. 73127. Writing Professional Documents in French The next session will take place from 26 April to 02 July 2004. This course is designed for people with a good level...

  11. Language Training: French Training

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. LANGUAGE TRAINING Françoise Benz tel. 73127 language.training@cern.ch General and Professional French Courses The next session will take place from 26 April to 02 July 2004. These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: Tel. 73127. Writing Professional Documents in French The next session will take place from 26 April to 02 July 2004. This course is designed for people with a good level of s...

  12. Periodic dark pulse emission induced by delayed feedback in a quantum well semiconductor laser

    Directory of Open Access Journals (Sweden)

    L. Li

    2012-12-01

    Full Text Available We report the experimental observation of periodic dark pulse emission in a quantum-well semiconductor laser with delayed optical feedback. We found that under appropriate operation conditions the laser can also emit a stable train of dark pulses. The repetition frequency of the dark pulse is determined by the external cavity length. Splitting of the dark pulse was also observed. We speculate that the observed dark pulse is a kind of temporal cavity soliton formed in the laser.

  13. Inductive Pulse Generation

    OpenAIRE

    Lindblom, Adam

    2006-01-01

    Pulsed power generators are a key component in compact systems for generation of high-power microwaves (HPM). HPM generation by virtual cathode devices such as Vircators put high demands on the source. The rise time and the pulse length of the source voltage are two key issues in the generation of HPM radiation. This thesis describes the construction and tests of several inductive high power pulse generators. The pulse generators were designed with the intent to deliver a pulse with fast rise...

  14. Nonlinear 6-fold enhancement of laser drilling efficiency by double pulse mode: prospective in medicine application

    Science.gov (United States)

    Pershina, N. S.; Pershin, S. M.; Cech, M.; Prochazka, I.

    2009-05-01

    The efficiency of laser ablation drilling of metal and dielectric (ceramic, glasses, etc.) samples with single and multiple laser pulses per one laser shot was experimentally studied. The laser is operated on the fundamental (1064 nm) wavelength of Nd:YAG laser with 30 ns pulse length or its second (532 nm) and third (351 nm) harmonics, respectively. The laser shot repletion rate was 1 Hz. The pulses in train were separated by 25-45 μs interval. The crater depth and drilling speed dependence increasing on pulse number in multipulse train was studied. The laser ablation normalized per pulse energy in train dependence is not linear function. The strong ablation enhancement was observed. The optimal (in sense the total pulse energy using) drilling can be obtained with double pulse mode compared with 3 - 5 pulses. Nonlinear more than 6 fold increasing of crater depth produced by the second pulse in train was detected. The mechanism of selective increasing of the second pulse interaction efficiency with the hard target is discussed. Experimental results explained in terms of double pulse mode laser ablation model. Spectroscopy study of laser plasma was observed to confirm discussed model of high efficiency for two laser pulse laser ablation. Efficiency of double pulse mode compared with multipulse mode is discussed to be more perspective for various applications of laser ablation. The medicine (surgery, dentist, ophthalmology and so on) application is the most prospective, for instance, the teeth drilling or glaucoma perforation, can be done with smaller energy value.

  15. Evaluating Training

    Institute of Scientific and Technical Information of China (English)

    Zhang Huanhai; Zhang Lei's

    2008-01-01

    @@ Clause 6.2.2: Competence, Awareness and Training in ISO9001:2000 standard sets the training requirements for organizations. Problems with evaluating the outcomes of training arise during examination and verification.

  16. Language Training: English Training

    CERN Multimedia

    Françoise Benz

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. General and Professional English Courses The next session will take place from 04 October 2004 to 11 February 2005 (3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow, tel. 72957. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be approximately 8 participants in...

  17. DIFFERENTIAL PULSE HEIGHT DISCRIMINATOR

    Science.gov (United States)

    Test, L.D.

    1958-11-11

    Pulse-height discriminators are described, specifically a differential pulse-height discriminator which is adapted to respond to pulses of a band of amplitudes, but to reject pulses of amplitudes greater or less than tbe preselected band. In general, the discriminator includes a vacuum tube having a plurality of grids adapted to cut off plate current in the tube upon the application of sufficient negative voltage. One grid is held below cutoff, while a positive pulse proportional to the amplltude of each pulse is applled to this grid. Another grid has a negative pulse proportional to the amplitude of each pulse simultaneously applied to it. With this arrangement the tube will only pass pulses which are of sufficlent amplitude to counter the cutoff bias but not of sufficlent amplitude to cutoff the tube.

  18. Language training: French training

    CERN Multimedia

    2008-01-01

    General and professional french coursesThe next session will take place from 14 April to 27 June 2008. These courses are open to all persons working on the CERN site and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs Nathalie Dumeaux: Tel. 78144. Writing Professional Documents in French The next session will take place from 14 April to 27 June 2008. This course is designed for people with a good level of spoken French. Duration: 30 hours Price: 660 CHF For further information and registration, please consult our Web pages: http://cern.ch/Training or contact Mrs Nathalie Dumeaux: Tel. 78144.

  19. Pulse-Width Jitter Measurement for Laser Diode Pulses

    Institute of Scientific and Technical Information of China (English)

    TANG Jun-Hua; WANG Yun-Cai

    2006-01-01

    @@ Theoretical analysis and experimental measurement of pulse-width jitter of diode laser pulses are presented. The expression of pulse power spectra with all amplitude jitter, timing jitter and pulse-width jitter is deduced.

  20. Hybrid chirped pulse amplification system

    Science.gov (United States)

    Barty, Christopher P.; Jovanovic, Igor

    2005-03-29

    A hybrid chirped pulse amplification system wherein a short-pulse oscillator generates an oscillator pulse. The oscillator pulse is stretched to produce a stretched oscillator seed pulse. A pump laser generates a pump laser pulse. The stretched oscillator seed pulse and the pump laser pulse are directed into an optical parametric amplifier producing an optical parametric amplifier output amplified signal pulse and an optical parametric amplifier output unconverted pump pulse. The optical parametric amplifier output amplified signal pulse and the optical parametric amplifier output laser pulse are directed into a laser amplifier producing a laser amplifier output pulse. The laser amplifier output pulse is compressed to produce a recompressed hybrid chirped pulse amplification pulse.

  1. Pulse bundles and passive harmonic mode-locked pulses in Tm-doped fiber laser based on nonlinear polarization rotation.

    Science.gov (United States)

    Wang, Xiong; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-03-10

    We demonstrate the nanosecond-level pulses in Tm-doped fiber laser generated by passively harmonic mode-locking. Nonlinear polarization rotation performed by two polarization controllers (PCs) is employed to induce the self-starting harmonic mode-locking. The fundamental repetition rate of the laser is 448.8 kHz, decided by the length of the cavity. Bundles of pulses with up to 17 uniform subpulses are generated due to the split of pulse when the pump power increases and the PCs are adjusted. Continuous harmonic mode-locked pulse trains are obtained with 1st to 6th and even more than 15th order when the positions of the PCs are properly fixed and the pump power is scaled up. The widths of all the uniform individual pulses are mostly 3-5 ns, and pulse with width of 304 ns at fundamental repetition rate can also be generated by adjusting the PCs. Hysteresis phenomenon of the passively harmonic mode-locked pulses' repetition frequency versus pump power is observed. The rather wide 3dB spectral bandwidth of the pulse train (25 nm) indicates that they may resemble noise-like pulses. PMID:24663948

  2. Language Training - French Training

    CERN Multimedia

    2007-01-01

    General and Professional French Courses The next session will take place from 29 January to 30 March 2007. These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz : Tel. 73127. Writing Professional Documents in French The next session will take place from 29 January to 30 March 2007. This course is designed for people with a good level of spoken French. Duration: 30 hours Price: 660 CHF (for 8 students) For further information and registration, please consult our Web pages:   http://cern.ch/Training or contact Mrs. Benz : Tel. 73127. Writing Professional Documents in English The next session will take place from January to June 2007 (break at Easter). This course is designed for people with a good level of spoken English. Duration: 30 hours Price: 660 CHF (for 8 students) Timetable will be fixed after discussion with the students. For registratio...

  3. Language Training: English Training

    CERN Multimedia

    Françoise Benz

    2004-01-01

    La prochaine session se déroulera du 04 octobre 2004 au 11 février 2005 (interruption de 3 semaines à Noël). Ces cours s'adressent à toute personne travaillant au CERN ainsi qu'à leur conjoint. Pour vous inscrire et voir tout le détail des cours proposés, consultez nos pages Web : http://cern.ch/Training Vous pouvez aussi contacter M. Liptow, tél. 72957. General and Professional English Courses The next session will take place from 04 October 2004 to 11 February 2005 (3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow, tel. 72957. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be approximately 8 participants ...

  4. Language Training: English Training

    CERN Multimedia

    Françoise Benz

    2004-01-01

    General and Professional English Courses The next session will take place from 04 October 2004 to 11 February 2005 (3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow, tel. 72957. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be approximately 8 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) For further information, please contact Mr. Liptow, tel. 72957. Date and timetable will be fixed when there are sufficient participants enrolled. FORMATION EN LANGUES LANGUAGE TRAINING Françoise Benz 73127 langua...

  5. Language Training: English Training

    CERN Document Server

    Françoise Benz

    2004-01-01

    General and Professional English Courses The next session will take place from 04 October 2004 to 11 February 2005 (3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow, tel. 72957. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be approximately 8 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) For further information, please contact Mr. Liptow, tel. 72957. Date and timetable will be fixed when there are sufficient participants enrolled. FORMATION EN LANGUES LANGUAGE TRAINING Françoise Benz 73127 languag...

  6. Pulse Pressure in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Jiri Parenica

    2012-02-01

    Full Text Available The review presents basic information about the pulse pressure. The variables related to pulse pressure are briefly explained - arterial stiffness, arterial compliance, pulse wave velocity, pulse pressure amplification and augmentation index. We present some recent trials and observational studies that show the importance of pulse pressure in clinical practice. Briefly the possibilities of influencing the pulse pressure are discussed.

  7. Studies of solid propellant combustion with pulsed radiography

    Science.gov (United States)

    Godai, T.; Tanemura, T.; Fujiwara, T.; Shimizu, M.

    1987-01-01

    Pulsed radiography was applied to observe solid propellant surface regression during rocket motor operation. Using a 150 KV flash X-ray system manufactured by the Field Emission Corporation and two kinds of film suppliers, images of the propellant surface of a 5 cm diameter end burning rocket motor were recorded on film. The repetition frame rate of 8 pulses per second and the pulse train length of 10 pulses are limited by the capability of the power supply and the heat build up within the X-ray tube, respectively. The experiment demonstrated the effectiveness of pulsed radiography for observing solid propellant surface regression. Measuring the position of burning surface images on film with a microdensitometer, quasi-instantaneous burning rate as a function of pressure and the variation of characteristic velocity with pressure and gas stay time were obtained. Other research items to which pulsed radiography can be applied are also suggested.

  8. UV pulse shaping for the photocathode RF gun

    Energy Technology Data Exchange (ETDEWEB)

    Yan Lixin, E-mail: yanlx@mail.tsinghua.edu.cn [Accelerator Laboratory, Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China); Key Laboratory of High Energy Radiation Imaging Fundamental Science for National Defense, Beijing 100084 (China); Du Qiang; Du Yingchao; Hua Jianfei; Huang Wenhui; Tang Chuanxiang [Accelerator Laboratory, Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084 (China); Key Laboratory of High Energy Radiation Imaging Fundamental Science for National Defense, Beijing 100084 (China)

    2011-05-01

    Recently, manipulation with the drive laser plays a significant role in high brightness electron beam production by the photocathode RF gun. The article takes efforts on the temporal shaping of the driving laser for the photocathode RF gun. Method based on pulse stacking by birefringent crystal of {alpha}-BBO serials was tried to directly shape ultraviolet laser pulse. Using four pieces of {alpha}-BBO crystals to separate an input UV pulse with appropriate duration into 16 sub-pulses can form a ps-spaced pulse train suitable for coherent THz production. The group delay dispersion induced by the crystals was also carefully considered. To avoid beam deterioration by long path propagation, imaging relay of the shaped pulse was applied.

  9. Generation of attosecond pulse pair in polar media by chirped few-cycle pulses

    Science.gov (United States)

    Hu, Pidong; Niu, Yueping; Wang, Xiangxin; Gong, Shangqing; Liu, Chengpu

    2016-09-01

    The high-order harmonic generation in a polar medium driven by an initially chirped few-cycle laser pulse is investigated via numerically solving the nonlinear Bloch or Maxwell-Bloch equations based on whether propagation effects are taken into account or not. As a result of the reduction of quantum trajectories number due to the introduction of chirps, an attosecond pulse pair (APP) is generated instead of a general attosecond pulse train. Moreover, the time delay between the two attosecond pulses is tunable. When propagation effects take roles, the peak intensities of the APP can be enhanced at suitable propagation distances without observable duration broadening, and such an enhancement can be modulated by changing medium density.

  10. Training Visions

    Science.gov (United States)

    Training, 2011

    2011-01-01

    In this article, "Training" asks the 2011 winners to give their predictions for what training--either in general or specifically at their companies--will look like in the next five to 10 years. Perhaps their "training visions" will spark some ideas in one's organization--or at least help prepare for what might be coming in the next decade or so.

  11. Pulsed laser machining apparatus

    International Nuclear Information System (INIS)

    Apparatus and method for directing a controlled number of laser pulses onto a work piece to be machined. More specifically, the laser machining apparatus includes an excitable laser and an excitation lamp for continuously exciting the laser to emit a sequence of laser pulses. The application of the laser pulses to the work piece is controlled by an inner-cavity shutter that is opened to permit a precise number of pulses to be directed onto the work piece. The frequency (REP RATE) and pulse width of the laser pulses are controlled by the excitation lamp and, in turn, are set to create a progressive weld of significant depth and structural integrity. In particular there is provided control means for counting the number of laser pulses applied to a machining site of the work piece, whereby a known controllable quantity of energy is imparted to each site. To this end, the counting of the laser pulses begins after the completion of a laser pulse, whereby the actuation of the inner-cavity shutter is not synchronized to the computer but rather to the laser emission so that only whole laser pulses will be applied to the site

  12. Nonlinear pulse compression

    OpenAIRE

    Grün, Alexander

    2014-01-01

    In this thesis I investigate two methods for generating ultrashort laser pulses in spectral regions which are ordinarily difficult to achieve by the existing techniques. These pulses are specially attractive in the study of ultrafast (few femtosecond) atomic and molecular dynamics. The first involves Optical Parametric Amplification (OPA) mediated by four-wave-mixing in gas and supports the generation of ultrashort pulses in the Near-InfraRed (NIR) to the Mid-InfraRed (MIR) spectral regio...

  13. Estimate of pulse-sequence data acquisition system for multi-dimensional measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Yasunori; Sakae, Takeji; Nohtomi, Akihiro; Matoba, Masaru [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering; Matsumoto, Yuzuru

    1996-07-01

    A pulse-sequence data acquisition system has been newly designed and estimated for the measurement of one- or multi-dimensional pulse train coming from radiation detectors. In this system, in order to realize the pulse-sequence data acquisition, the arrival time of each pulse is recorded to a memory of a personal computer (PC). For the multi-dimensional data acquisition with several input channels, each arrival-time data is tagged with a `flag` which indicates the input channel of arriving pulse. Counting losses due to the existence of processing time of the PC are expected to be reduced by using a First-In-First-Out (FIFO) memory unit. In order to verify this system, a computer simulation was performed, Various sets of random pulse trains with different mean pulse rate (1-600 kcps) were generated by using Monte Carlo simulation technique. Those pulse trains were dealt with another code which simulates the newly-designed data acquisition system including a FIFO memory unit; the memory size was assumed to be 0-100 words. And the recorded pulse trains on the PC with the various FIFO memory sizes have been observed. From the result of the simulation, it appears that the system with 3 words FIFO memory unit works successfully up to the pulse rate of 10 kcps without any severe counting losses. (author)

  14. Damage threshold and focusability of mid-infrared free-electron laser pulses gated by a plasma mirror with nanosecond switching pulses

    CERN Document Server

    Wang, Xiaolong; Zen, Heishun; Kii, Toshiteru; Ohgaki, Hideaki

    2013-01-01

    The presence of a pulse train structure of an oscillator-type free-electron laser (FEL) results in the immediate damage of a solid target upon focusing. We demonstrate that the laser-induced damage threshold can be significantly improved by gating the mid-infrared (MIR) FEL pulses with a plasma mirror. Although the switching pulses we employ have a nanosecond duration which does not guarantee the clean wavefront of the gated FEL pulses, the high focusablity is experimentally confirmed through the observation of spectral broadening by a factor of 2.1 when we tightly focus the gated FEL pulses onto the Ge plate.

  15. Language Training - English Training

    CERN Multimedia

    HR Department

    2009-01-01

    General and Professional English Courses The next session will take place: from 2nd March to end of June 2009 (1/2 weeks break at Easter). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Nathalie Dumeaux, tel. 78144. Oral Expression The next session will take place from 2nd March to end of June 2009 (1/2 weeks break at Easter). This course is intended for people with a good knowledge of English who want to enhance their speaking skills. There will be on average of 8 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 30 hours Price: 660 CHF (for a minimum of 8 students) Writing Professional Documents in English The next session will take place from 2nd March to end of June 2009 (1/2 weeks break at Easter). This course is designed for people w...

  16. Language Training - English Training

    CERN Multimedia

    HR Department

    2009-01-01

    General and Professional English Courses The next session will take place: from 2nd March to end of June 2009 (1/2 weeks break at Easter). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Nathalie Dumeaux, tel. 78144. Oral Expression The next session will take place from 2nd March to end of June 2009 (1/2 weeks break at Easter). This course is intended for people with a good knowledge of English who want to enhance their speaking skills. There will be an average of 8 participants per class. Speaking activities will include discussions, meeting simulations, role-plays, etc., depending on the needs of the students. Duration: 30 hours Price: 660 CHF (for a minimum of 8 students) Writing Professional Documents in English The next session will take place from 2nd March to end of June 2009 (1/2 weeks break at Easter). This course is designed for people ...

  17. Opportunities in pulse combustion

    Science.gov (United States)

    Brenchley, D. L.; Bomelburg, H. J.

    1985-10-01

    In most pulse combustors, the combustion occurs near the closed end of a tube where inlet valves operate in phase with the pressure amplitude variations. Thus, within the combustion zone, both the temperature and the pressure oscillate around a mean value. However, the development of practical applications of pulse combustion has been hampered because effective design requires the right combination of the combustor's dimensions, valve characteristics, fuel/oxidizer combination, and flow pattern. Pulse combustion has several additional advantages for energy conversion efficiency, including high combustion and thermal efficiency, high combustion intensity, and high convective heat transfer rates. Also, pulse combustion can be self-aspirating, generating a pressure boost without using a blower. This allows the use of a compact heat exchanger that may include a condensing section and may obviate the need for a chimney. In the last decade, these features have revived interest in pulse combustion research and development, which has resulted in the development of a pulse combustion air heater by Lennox, and a pulse combustion hydronic unit by Hydrotherm, Inc. To appraise this potential for energy savings, a systematic study was conducted of the many past and present attempts to use pulse combustion for practical purposes. The authors recommended areas where pulse combustion technology could possibly be applied in the future and identified areas in which additional R and D would be necessary. Many of the results of the study project derived from a special workshop on pulse combustion. This document highlights the main points of the study report, with particular emphasis on pulse combustion application in chemical engineering.

  18. Control of the polarization of attosecond pulses using a two-color field

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Camilo; Hoffmann, David J; Torres, Ricardo; Chipperfield, Luke E; Marangos, Jonathan P [Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom)], E-mail: camilo@usal.es

    2009-11-15

    Control over the polarization of an attosecond pulse train (APT) is demonstrated theoretically using orthogonally polarized two-color fields. The carrier envelope phase of the two pulses is used as a control parameter to generate both an APT with linear polarization in two nearly perpendicular planes or a train of elliptically polarized pulses of alternating helicity. By using few-cycle driving laser fields an isolated attosecond pulse with elliptical polarization is shown to be generated after selecting the cut-off region of the harmonic spectrum. The control mechanism is explained in terms of classical trajectories.

  19. Optimal Design and Experimental characterisation of short optical pulse compression using CDPF

    DEFF Research Database (Denmark)

    Yujun, Qian; Quist, S.

    1999-01-01

    We present optimal design and experimental characterisation ofoptical pulse compression using a comblike dispersion-profiled fibre(CDPF). A pulse train at 10GHz with puslewidth of 1ps and side-lobesuppression of 30dB can be obtained.......We present optimal design and experimental characterisation ofoptical pulse compression using a comblike dispersion-profiled fibre(CDPF). A pulse train at 10GHz with puslewidth of 1ps and side-lobesuppression of 30dB can be obtained....

  20. BIOLOGICAL EFFECTS OF PULSED SHORT WAVE TREATMENT. AN EXPERIMENTAL STUDY

    OpenAIRE

    Dogaru Gabriela; Crăciun Constantin

    2015-01-01

    Pulsed short waves are short electromagnetic waves emitted as intermittent trains with a fixed duration, separated by free intervals of variable duration. The biological effects of pulsed short waves could be explained according to most of the authors by an activation of cellular enzymatic reactions, a stimulation of energy metabolism, a stimulation of liver function, of adrenal gland function and of the reticulocyte system, changes in cell permeability, by an increase of peripheral blood flo...

  1. Linear induction accelerator and pulse forming networks therefor

    Science.gov (United States)

    Buttram, Malcolm T.; Ginn, Jerry W.

    1989-01-01

    A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities.

  2. Quasi-phase-matching of high harmonic generation using counter-propagating pulses

    OpenAIRE

    O’Keeffe K.; Hooker S. M.

    2013-01-01

    We investigate quasi-phase-matching over a range of harmonic orders using trains of up to 8 uniformly-spaced counter-propagating pulses. For trains of up to 4 pulses the measured enhancement of the harmonic signal scales with the number of pulses N as (N+1)2, as expected. However, for trains with N > 4, no further enhancement of the harmonic signal is observed. The effect is ascribed to changes in the coherence length with the generating medium. The pressure dependence of quasi-phase-matching...

  3. Pulsed Plasma Electron Sources

    Science.gov (United States)

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  4. DogPulse

    DEFF Research Database (Denmark)

    Skovgaard, Christoffer; Thomsen, Josephine Raun; Verdezoto, Nervo;

    2015-01-01

    This paper presents DogPulse, an ambient awareness system to support the coordination of dog walking among family members at home. DogPulse augments a dog collar and leash set to activate an ambient shape-changing lamp and visualize the last time the dog was taken for a walk. The lamp gradually c...

  5. Pulse Shaping Entangling Gates and Error Supression

    Science.gov (United States)

    Hucul, D.; Hayes, D.; Clark, S. M.; Debnath, S.; Quraishi, Q.; Monroe, C.

    2011-05-01

    Control of spin dependent forces is important for generating entanglement and realizing quantum simulations in trapped ion systems. Here we propose and implement a composite pulse sequence based on the Molmer-Sorenson gate to decrease gate infidelity due to frequency and timing errors. The composite pulse sequence uses an optical frequency comb to drive Raman transitions simultaneously detuned from trapped ion transverse motional red and blue sideband frequencies. The spin dependent force displaces the ions in phase space, and the resulting spin-dependent geometric phase depends on the detuning. Voltage noise on the rf electrodes changes the detuning between the trapped ions' motional frequency and the laser, decreasing the fidelity of the gate. The composite pulse sequence consists of successive pulse trains from counter-propagating frequency combs with phase control of the microwave beatnote of the lasers to passively suppress detuning errors. We present the theory and experimental data with one and two ions where a gate is performed with a composite pulse sequence. This work supported by the U.S. ARO, IARPA, the DARPA OLE program, the MURI program; the NSF PIF Program; the NSF Physics Frontier Center at JQI; the European Commission AQUTE program; and the IC postdoc program administered by the NGA.

  6. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    OpenAIRE

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten; Galili, Michael; Peucheret, Christophe

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.

  7. Pulsed energy storage antennas for ionospheric modification

    Directory of Open Access Journals (Sweden)

    R. F. Wuerker

    2005-01-01

    Full Text Available Interesting, "new", very high peak-power pulsed radio frequency (RF antennas have been assembled at the HIPAS Observatory (Alaska, USA and also at the University of California at Los Angeles (UCLA, USA; namely, a pair of quarter wavelength (λ/4 long cylindrical conductors separated by a high voltage spark gap. Such a combination can radiate multi-megawatt RF pulses whenever the spark gap fires. The antenna at HIPAS is 53m long (λ/2 with a central pressurized SF6 spark gap. It is mounted 5 meters (λ/21 above a ground plane. It radiates at 2.85MHz. The two antenna halves are charged to ± high voltages by a Tesla coil. Spark gap voltages of 0.4 MV (at the instant of spark gap closure give peak RF currents of ~1200A which correspond to ~14 MW peak total radiated power, or ~56 MW of Effective Radiated Power (ERP. The RF pulse train is initially square, decaying exponentially in time with Qs of ~50. Two similar but smaller 80-MHz antennas were assembled at UCLA to demonstrate their synchronization with a pulsed laser which fired the spark gaps in the two antennas simultanoeously. These experiments show that one can anticipate a pulsed array of laser synchronized antennas having a coherent Effective Radiated Power (ERP>10GW. One can even reconsider a pulse array radiating at 1.43MHz which corresponds to the electron gyrofrequency in the Earth's magnetic field at ~200km altitude. These "new" pulsed high power antennas are hauntingly similar to the ones used originally by Hertz (1857-1894 during his (1886-1889 seminal verifications of Maxwell's (1864 theory of electrodynamics.

  8. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten;

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  9. Parabolic similariton Yb-fiber laser with triangular pulse evolution

    Science.gov (United States)

    Wang, Sijia; Wang, Lei

    2016-04-01

    We propose a novel mode-locked fiber laser design which features a passive nonlinear triangular pulse formation and self-similar parabolic pulse amplification intra cavity. Attribute to the nonlinear reshaping progress in the passive fiber, a triangular-profiled pulse with negative-chirp is generated and paved the way for rapid and efficient self-similar parabolic evolution in a following short-length high-gain fiber. In the meanwhile, the accompanied significantly compressed narrow spectrum from this passive nonlinear reshaping also gives the promise of pulse stabilization and gain-shaping robustness without strong filtering. The resulting short average intra-cavity pulse duration, low amplified spontaneous emission (ASE) and low intra-cavity power loss are essential for the low-noise operation. Simulations predict this modelocked fiber laser allows for high-energy ultra-short transform-limited pulse generation exceeding the gain bandwidth. The output pulse has a de-chirped duration (full-width at half maximum, FWHM) of 27 fs. In addition to the ultrafast laser applications, the proposed fiber laser scheme can support low-noise parabolic and triangular pulse trains at the same time, which are also attractive in optical pulse shaping, all-optical signal processing and high-speed communication applications.

  10. Repetitive transcranial magnetic stimulator with controllable pulse parameters.

    Science.gov (United States)

    Peterchev, Angel V; Murphy, David L; Lisanby, Sarah H

    2011-06-01

    The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 µs and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency. PMID:21540487

  11. Photonic integrated circuit as a picosecond pulse timing discriminator.

    Science.gov (United States)

    Lowery, Arthur James; Zhuang, Leimeng

    2016-04-18

    We report the first experimental demonstration of a compact on-chip optical pulse timing discriminator that is able to provide an output voltage proportional to the relative timing of two 60-ps input pulses on separate paths. The output voltage is intrinsically low-pass-filtered, so the discriminator forms an interface between high-speed optics and low-speed electronics. Potential applications include timing synchronization of multiple pulse trains as a precursor for optical time-division multiplexing, and compact rangefinders with millimeter dimensions. PMID:27137311

  12. 20-GHz optical pulse source based on cascaded electroabsorption modulators

    Institute of Scientific and Technical Information of China (English)

    Yuanshan Liu; Jianguo Zhang; Wei Zhao

    2007-01-01

    A high-quality low-timing-jitter 20-GHz optical pulse train is generated by using two cascaded sinusoidally driven electroabsorption modulators (EAMs) at very low bias voltage of -0.8 V in conjunction with a tunable distributed feedback (DFB) semiconductor laser. An approximate transform-limited optical pulse,with the pulse width less than 7 ps, the spectral width of 0.3 nm, and the side-mode suppression ratio (SMSR) above 20 dB, is obtained by tuning the optical delay line.

  13. Photonic integrated circuit as a picosecond pulse timing discriminator.

    Science.gov (United States)

    Lowery, Arthur James; Zhuang, Leimeng

    2016-04-18

    We report the first experimental demonstration of a compact on-chip optical pulse timing discriminator that is able to provide an output voltage proportional to the relative timing of two 60-ps input pulses on separate paths. The output voltage is intrinsically low-pass-filtered, so the discriminator forms an interface between high-speed optics and low-speed electronics. Potential applications include timing synchronization of multiple pulse trains as a precursor for optical time-division multiplexing, and compact rangefinders with millimeter dimensions.

  14. Ionisation of Rydberg hydrogen atom near a metal surface by short pulse laser

    Institute of Scientific and Technical Information of China (English)

    Wang Lei; Yang Hai-Feng; Liu Xiao-Jun; Liu Hong-Ping

    2010-01-01

    In the ionisation of Rydberg hydrogen atoms near a metal surface,the electron will escape from the nucleus and arrive at the detector in a time sequence.This probability flux train relies on the initial electron wave packet irradiated by the laser pulse.For simplicity,the laser pulse is usually simplified to a delta function in energy domain,resulting in a sharp initial arrival time with an exponentially decaying tail at the detector.Actually and semiclassically,the initial outgoing wave should be modeled as an ensemble of trajectories propagating away from the atomic core in all directions with a range of launch times and a range of energies.In this case,each pulse in the pulse train is averaged out rather than a sharp profile.We examine how energy and time averaging of the electron wave packet affects the resolution of escaping electron pulses and study the energy dependence of the arrival time for each pulse in the ionisation train.An optimization condition for the laser pulse shape to generate narrow ionisation electron pulse in the train is obtained.The ionisation rates with various excitation energy are calculated also,which show the excitation to higher N Rydberg states will narrow the electron pulse as well.

  15. Amplified reference pulse storage for low-coherence pulsed Doppler lidar.

    Science.gov (United States)

    Shen, Jyi-Lai; Künnemeyer, Rainer

    2006-11-10

    We present a lidar concept for wind-speed measurements, in which a pulsed laser is used as the source for measurement and reference beams. A fraction of the transmitted pulse is stored in a fiber-optic ring resonator with a path length longer than the pulse. The output of the resonator is a pulse train that is used as the reference beam and can be mixed with the Doppler-shifted measurement signal. Because this reference has traveled a distance equivalent to the measurement beam's path length, low-coherence sources can be used. Inserting an erbium-doped fiber amplifier into the resonator ensures that the stored pulses do not decay in amplitude. Experiments prove that 16 reference pulses of sufficiently constant amplitude and stability can be generated. This would correspond to a measurement range of 240 m in free air over which the returned signal is sampled at equal intervals. Velocity measurements of a hard target have been carried out in the range of 1-10 m/s. The Doppler-measured velocities agree with tachometer reference measurements within +/-0.09 m/s. PMID:17068580

  16. Field training

    International Nuclear Information System (INIS)

    Individualized, personal training can be used to increase an employee's awareness of the HSE program. Such training can stimulate personal commitment and provide personal skills that can be utilized for the benefit of the overall HSE effort. But, providing such training within our industry can be a difficult task due to the scheduling, travel arrangements, and cost associated with bringing employees from isolated, remote locations to centrally located training facilities. One method of overcoming these obstacles involves the use of field instructors to provide the training at the many, and varied number of individuals can be reached with minimal disruption to their work scheduling or to their time off. In fact, this type of on-site training is already used by some oil companies and drilling contractors with encouraging results. This paper describes one drilling contractor's experiences with such a training program. The results after eight years how that this program not only can provide and efficient, economical means of employee training, but also can have a direct application to employee motivation regarding a company's HSE effort

  17. [Teacher Training.

    Science.gov (United States)

    Palmatier, Robert A., Ed.

    1977-01-01

    This issue collects three articles concerning reading-teacher training. "Language, Failure, and Panda Bears" by Patricia M. Cunningham calls attention to dialect difficulties in the classroom and provides ideas for teacher training programs and for public schools to solve this problem. William H. Rupley, in "Improving Teacher Effectiveness in…

  18. Operator training

    International Nuclear Information System (INIS)

    The traditional operator job is changing, which among other things has generated a need for better job training. Surprisingly increased process automation has lead to increased operator qualifications, i.e. basic job training but also up-date and rehearsal training within certain fixed intervals. There are several, similar models for instructional system development available in the literature. One model which is of special interest integrates Operator Training development and Man-Machine Interfaces development. The extent to which Systematic Operator Training has been implemented varies with branches and companies. The nuclear power branch is given as an example in the report. This branch probably represents something better than the average among the process industries.(author)

  19. Training Standardization

    International Nuclear Information System (INIS)

    The article describes the benefits of and required process and recommendations for implementing the standardization of training in the nuclear power industry in the United States and abroad. Current Information and Communication Technologies (ICT) enable training standardization in the nuclear power industry. The delivery of training through the Internet, Intranet and video over IP will facilitate this standardization and bring multiple benefits to the nuclear power industry worldwide. As the amount of available qualified and experienced professionals decreases because of retirements and fewer nuclear engineering institutions, standardized training will help increase the number of available professionals in the industry. Technology will make it possible to use the experience of retired professionals who may be interested in working part-time from a remote location. Well-planned standardized training will prevent a fragmented approach among utilities, and it will save the industry considerable resources in the long run. It will also ensure cost-effective and safe nuclear power plant operation

  20. ENGLISH TRAINING

    CERN Document Server

    2003-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. LANGUAGE TRAINING Françoise Benz tel. 73127 language.training@cern.ch PLACES AVAILABLE Writing Professional Documents in English This course is designed for people with a good level of spoken English who need to improve their professional writing (administrative, scientific, technical). Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) Date and timetable will be fixed when there are sufficient participants enrolled. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their sp...

  1. Efficient Pulsed Quadrupole

    CERN Document Server

    Petzenhauser, I.; Spiller, P.; Tenholt, C.

    2016-01-01

    In order to raise the focusing gradient in case of bunched beam lines, a pulsed quadrupole was designed. The transfer channels between synchrotrons as well as the final focusing for the target line are possible applications. The quadrupole is running in a pulsed mode, which means an immense saving of energy by avoiding standby operation. Still the high gradients demand high currents. Hence a circuit had to be developed which is able to recover a significant amount of the pulsing energy for following shots. The basic design of the electrical circuit of the quadrupole is introduced. Furthermore more energy efficient circuits are presented and the limits of adaptability are considered.

  2. Pulse joining cartridges

    Energy Technology Data Exchange (ETDEWEB)

    Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

    2016-08-23

    A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

  3. Amplification of high power picosecond laser pulses in multiatmosphere carbon dioxide amplifier

    International Nuclear Information System (INIS)

    High power ultrashort carbon dioxide laser pulses are useful in the study of molecular vibrations: vibrational relaxation, the exchange of vibrational energy between modes and molecules, etc. However multiatmosphere CO2 lasers are studied less than the other amplifying media. This work is devoted to a systematic theoretical investigation of picosecond pulse amplification by high pressure CO2 amplifier. The new features of this process are connected with the discrete structure of CO2 gain spectrum, phase modulation of input pulses as well as with an electron density wave which follows the powerful IR pulse in gas medium of TE CO2 amplifier. At the linear stage of amplification a short input pulse (τ 20 ps) no pulse formation takes place. A nonsteady-state theory has been developed of electron impact ionization of CO2 laser medium by intense IR picosecond pulses. The electron density wave produced by ionization process follows the laser pulse and can result in pulse envelope distortion and phase modulation. In particular it may cause pulse energy limitation and frequency chirping. The influence of phase modulation on the IR short pulse amplification has also been investigated. It is shown that the input pulse chirp may cause a considerable pulse envelope and frequency oscillatory modulation. It may be used for the generation of pulse trains of terahertz repetition rate which is useful for spectroscopic applications. (author)

  4. Training Attestations

    CERN Multimedia

    HR Department

    2004-01-01

    In the past, paper Training Attestations were printed during the first quarter of a New Year for Staff Members having followed courses and seminars the previous year in the context of CERN's official Training Programmes.  The attestations were sent to Divisional Training Officers (DTO's) for distribution to all Staff Members concerned within their Division. In practise many Staff Members did not find this paper useful, however some expressed a wish to be able to have access to a self-service facility in case of need. This change was discussed by the Joint Training Board (JTB) and with the DTO's during 2003 and was supported. As a consequence, following a collaboration between HR-PMD and IT-AIS, from 2004 onwards paper Training Attestations will no longer be printed and distributed as before. Those requiring a list of training followed in the past can now obtain their attestation directly from the Human Resources Toolkit (HRT) application for all training followed since 1997. https://hrt.cern...

  5. LANGUAGE TRAINING

    CERN Document Server

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. LANGUAGE TRAINING Françoise Benz tel. 73127 language.training@cern.ch FRENCH TRAINING General and Professional French Courses The next session will take place from 26 January to 02 April 2004. These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: Tel. 73127. Writing Professional Documents in French The next session will take place from 26 January to 02 April 2004. This course is designed for people wi...

  6. LANGUAGE TRAINING

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. LANGUAGE TRAINING Françoise Benz tel. 73127 language.training@cern.ch FRENCH TRAINING General and Professional French Courses The next session will take place from 26 January to 02 April 2004. These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz : Tel. 73127. Writing Professional Documents in French The next session will take place from 26 January to 02 April 2004. This course is designed for peop...

  7. Intense pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Kustom, R.L.

    1981-01-01

    Accelerator requirements for pulsed spallation neutron sources are stated. Brief descriptions of the Argonne IPNS-I, the Japanese KENS, Los Alamos Scientific Laboratory WNR/PSR, the Rutherford Laboratory SNS, and the West German SNQ facilities are presented.

  8. Pulse Coil Tester

    Science.gov (United States)

    Simon, Richard A.

    1988-01-01

    Set of relays tested easily and repeatedly. Pulse coil tester causes coil under test to generate transient voltage; waveform indicates condition of coil. Tester accommodates assembly of up to four coils at a time.

  9. A directive pulse antenna

    OpenAIRE

    Titov, A.N.; Titov, A. A.

    2003-01-01

    Using quite general concepts as guidance in the design of an antenna for short pulse transmission and reception, a new type of horn-antenna has been devised. A certain variety of experimental data obtained by the antenna are presented.

  10. Synchronization of Fourier-Synthesized Optical Pulses to a Mode-Locked Optical Clock

    Institute of Scientific and Technical Information of China (English)

    Masaharu; Hyodo; Kazi; Sarwal; Abedin; Noriaki; Onodera; Masayoshi; Watanabe

    2003-01-01

    A Fourier-synthesized 40-GHz optical pulse train was successfully synchronized to an 8-GHz optical clock generated from a mode-locked fiber ring laser. The measured timing jitter of the synchronization was 0.43 ps.

  11. Ultrashort pulse induced nanogratings

    Directory of Open Access Journals (Sweden)

    Nolte Stefan

    2013-11-01

    Full Text Available When intense femtosecond laser pulses are focused into a glass substrate, self-organized periodic nanostructures, so-called nanogratings, are generated in a certain parameter regime. To clarify the ultimate structure of the nanogratings we employed focused ion beam (FIB milling and small angle X-ray scattering (SAXS. The results considerably show that voids are the primary constituents and their number increases with ongoing exposure to laser pulses. Potential applications will be highlighted.

  12. Magnetic Pulse Welding Technology

    OpenAIRE

    Ahmad K. Jassim

    2011-01-01

    In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by weld...

  13. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  14. Repetition rate tunable ultra-short optical pulse generation based on electrical pattern generator

    Institute of Scientific and Technical Information of China (English)

    Xin Fu; Hongming Zhang; Meng Yan; Minyu Yao

    2009-01-01

    @@ An actively mode-locked laser with tunable repetition rate is proposed and experimentally demonstrated based on a programmable electrical pattern generator.By changing the repetition rate of the electrical patterns applied on the in-cavity modulator, the repetition rate of the output optical pulse sequences changes accordingly while the pulse width of the optical pulse train remains almost constant.In other words, the output ultra-short pulse train has a tunable duty cycle.In a proof-of-principle experiment, optical pulses with repetition rates of 10, 5, 2.5 and 1.25 GHz are obtained by adjusting the electrical pattern applied on the in-cavity modulator while their pulse widths remain almost unchanged.

  15. A low-cost programmable pulse generator for physiology and behavior

    Directory of Open Access Journals (Sweden)

    Joshua I Sanders

    2014-12-01

    Full Text Available Precisely timed experimental manipulations of the brain and its sensory environment are often employed to reveal principles of brain function. While complex and reliable pulse trains for temporal stimulus control can be generated with commercial instruments, contemporary options remain expensive and proprietary. We have developed Pulse Pal, an open source device that allows users to create and trigger software-defined trains of voltage pulses with high temporal precision. Here we describe Pulse Pal’s circuitry and firmware, and characterize its precision and reliability. In addition, we supply online documentation with instructions for assembling, testing and installing Pulse Pal. While the device can be operated as a stand-alone instrument, we also provide application programming interfaces in several programming languages. As an inexpensive, flexible and open solution for temporal control, we anticipate that Pulse Pal will be used to address a wide range of instrumentation timing challenges in neuroscience research.

  16. Saturation properties of four-wave mixing between short optical pulses in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.; Diez, S.

    1999-01-01

    Summary form only given. The authors report the first comparison between theory and experiment on the four wave mixing between trains of short pulses in semiconductor optical amplifiers. The theory is able to explain all qualitative features seen in the experiment.......Summary form only given. The authors report the first comparison between theory and experiment on the four wave mixing between trains of short pulses in semiconductor optical amplifiers. The theory is able to explain all qualitative features seen in the experiment....

  17. Strength Training

    Science.gov (United States)

    ... person's own weight to build muscles and strength. Olympic lifting, or powerlifting, which people often think of ... in the group effectively. Here are some basic rules to follow in strength training: Start with body ...

  18. Supervisor training

    DEFF Research Database (Denmark)

    Pedersen, Inge Nygaard

    2015-01-01

    This article fills a gap in knowledge about supervisor training programmes in the field of music therapy in Europe. Sparse research exists which demonstrates evidence of effective professional supervision upon the outcome of music therapy clinical practice. The article has its focus on the experi......This article fills a gap in knowledge about supervisor training programmes in the field of music therapy in Europe. Sparse research exists which demonstrates evidence of effective professional supervision upon the outcome of music therapy clinical practice. The article has its focus...... on the experience of an integrated supervisor training programme offered in Aalborg, Denmark in 2009/2010. In this programme general issues of professional supervision and the application of artistic media as a core element in the supervisory process were Integrated. It is the hope of the author that this article...... will inspire other music therapists to develop supervisor training programmes for professional music therapists and also to undertake further research into professional supervision....

  19. Pulse Extinction Ratio Improvement Using SPM in an SOA for OTDM Systems Applications

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup; Olsson, B.-E.; Blumenthal, D. J.

    2002-01-01

    Improvement of pulse extinction ratio from 15-20 dB to approximately 40 dB of a 10-GHz pulse train is demonstrated using the self-phase modulation-induced spectral shift caused by a semiconductor optical amplifier (SOA). The improvement permits penalty-free optical time-division multiplexing to 40...

  20. Low Current, Long Beam Pulse with SLED

    International Nuclear Information System (INIS)

    The 3 km long linac at the Stanford Linear Accelerator Center (SLAC) is used for fixed target experiments such as E-155, with energies up to 50 GeV. The SLAC Energy Development (SLED) system increase the maximum no-load energy by a factor of 1.6, but it also causes a varying beam energy curve. To provide a long pulse or bunch train for the experiment the energy profile has to be flat. Besides more sophisticated methods such as varying the phase of two klystrons feeding one structure section as proposed in the NLC design, we describe the method used for E-155 in spring of 1997. The desired low charged beam didn't have any significant beam loading, but by inserting a 1800 phase notch during the SLED pulse, a beam pulse of up to 500 ns was achieved. The energy range without compensation would have been 15%, while with compensation the energy spread was reduced to about 0.15%. The phase notch was achieved by triggering a pair of two additional 180d0 phase switches about half a structure fill-time after the SLED pulse was triggered. Simulations are compared with the experimental result

  1. Development of 12-Pulse Regulated Rectifier Circuit for Traction Substation

    OpenAIRE

    Sh. N. Nasirov

    2014-01-01

    The paper proposes a power circuit of a regulated 12-pulse direct current converter and a thyristor control impulse diagram for traction substations providing the best electric power supply of a rolling stock, train traction efficiency,  smooth direction regulation.

  2. High voltage pulse generator

    Science.gov (United States)

    Fasching, George E.

    1977-03-08

    An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

  3. Novel Method of Unambiguous Moving Target Detection in Pulse-Doppler Radar with Random Pulse Repetition Interval

    Directory of Open Access Journals (Sweden)

    Liu Zhen

    2012-03-01

    Full Text Available Blind zones and ambiguities in range and velocity measurement are two important issues in traditional pulse-Doppler radar. By generating random deviations with respect to a mean Pulse Repetition Interval (PRI, this paper proposes a novel algorithm of Moving Target Detection (MTD based on the Compressed Sensing (CS theory, in which the random deviations of the PRIare converted to the Restricted Isometry Property (RIP of the observing matrix. The ambiguities of range and velocity are eliminated by designing the signal parameters. The simulation results demonstrate that this scheme has high performance of detection, and there is no ambiguity and blind zones as well. It can also shorten the coherent processing interval compared to traditional staggered PRI mode because only one pulse train is needed instead of several trains.

  4. Herophilus on pulse

    Directory of Open Access Journals (Sweden)

    Afonasin, Eugene

    2015-01-01

    Full Text Available The first detailed study of the pulse (sphygmology is associated in antiquity with Herophilus (the end of the 4th century BCE, an Alexandrian physician, renowned for his anatomical discoveries. The scholars also attribute to him a discovery of a portable and adjustable water-clock, used for measuring ‘natural’ and ‘unnatural’ pulse and, accordingly, temperature of the patient. In the article we translate the principal ancient evidences and comment upon them. We study both the practical aspects of ancient sphygmology and the theoretical speculations associated with it. Ancient theory of proportion and musical harmony allowed to build a classification of the pulses, but the medical experience did not fit well in the Procrustean bed of this rather simple theory.

  5. Pulsed Artificial Electrojet Generation

    Science.gov (United States)

    Papadopoulos, K.

    2008-12-01

    Traditional techniques for generating low frequency signals in the ULF/ELF range (.1-100 Hz) and rely on ground based Horizontal Electric Dipole (HED) antennas. It is, furthermore, well known that a Vertical Electric Dipole (VED) is by more than 50 dB more efficient than a HED with the same dipole current moment. However, the prohibitively long length of VED antennas in the ELF/ULF range coupled with voltage limitations due to corona discharge in the atmosphere make them totally impracticable. In this paper we discuss a novel concept, inspired by the physics of the equatorial electrojet, that allows for the conversion of a ground based HED to a VED in the E-region of the equatorial ionosphere with current moment comparable to the driving HED. The paper focuses in locations near the dip-equator, where the earth's magnetic is in predominantly in the horizontal direction. The horizontal electric field associated with a pulsed HED drives a large Hall current in the ionospheric E-region, resulting in a vertical current. It is shown that the pulsed vertical current in the altitude range 80-130 km, driven by a horizontal electric field of, approximately, .1 mV/m at 100 km altitude, is of the order of kA. This results in a pulsed VED larger than 106 A-m. Such a pulsed VED will drive ELF/ULF pulses with amplitude in excess of .1 nT at a lateral range larger than few hundred kilometers. This is by three orders of magnitude larger than the one expected by a HED with comparable current moment. The paper will conclude with the description of a sneak-through technique that allows for creating pulsed electric fields in the ionosphere much larger than expected from steady state oscillatory HED antennas.

  6. Pulse Doppler radar

    CERN Document Server

    Alabaster, Clive

    2012-01-01

    This book is a practitioner's guide to all aspects of pulse Doppler radar. It concentrates on airborne military radar systems since they are the most used, most complex, and most interesting of the pulse Doppler radars; however, ground-based and non-military systems are also included. It covers the fundamental science, signal processing, hardware issues, systems design and case studies of typical systems. It will be a useful resource for engineers of all types (hardware, software and systems), academics, post-graduate students, scientists in radar and radar electronic warfare sectors and milit

  7. Millimicrosecond pulse techniques

    CERN Document Server

    Lewis, Ian A D

    1959-01-01

    Millimicrosecond Pulse Techniques, Second Edition focuses on millimicrosecond pulse techniques and the development of devices of large bandwidth, extending down to comparatively low frequencies (1 Mc/s). Emphasis is on basic circuit elements and pieces of equipment of universal application. Specific applications, mostly in the field of nuclear physics instrumentation, are considered. This book consists of eight chapters and opens with an introduction to some of the terminology employed by circuit engineers as well as theoretical concepts, including the laws of circuit analysis, Fourier analysi

  8. Bandpass calibration of a wideband spectrometer using pulse injection

    CERN Document Server

    Patra, Nipanjana; Ekers, Ron; Roberts, Paul

    2015-01-01

    We present a novel time domain concept for determining the bandpass response of a system by injecting a nanosecond pulse and capturing the system voltage output. A pulse of sub-nanosecond duration contains all frequency components with constant amplitude up to 1~GHz. Hence, this method can accurately determine the system bandpass response to a broadband signal. A train of pulses are coherently accumulated providing very high signal-to-noise calibration. The basic concept is demonstrated using a pulse generator-accumulator setup realised in a Bedlam board which is a high speed digital signal processing unit. The same system was used at the Parkes Radio Telescope between 2--13 October 2013 and we demonstrate its powerful diagnostic capability. We also present some initial test data from this experiment.

  9. Relativistic Doppler effect: universal spectra and zeptosecond pulses.

    Science.gov (United States)

    Gordienko, S; Pukhov, A; Shorokhov, O; Baeva, T

    2004-09-10

    We report on a numerical observation of the train of zeptosecond pulses produced by the reflection of a relativistically intense femtosecond laser pulse from the oscillating boundary of an overdense plasma because of the Doppler effect. These pulses promise to become unique experimental and technological tools since their length is of the order of the Bohr radius and the intensity is extremely high proportional, variant 10(19) W/cm(2). We present the physical mechanism, analytical theory, and direct particle-in-cell simulations. We show that the harmonic spectrum is universal: the intensity of nth harmonic scales as 1/n(p) for n<4gamma(2), where gamma is the largest gamma factor of the electron fluid boundary, and p=3 and p=5/2 for the broadband and quasimonochromatic laser pulses, respectively.

  10. Graphene based widely-tunable and singly-polarized pulse generation with random fiber lasers

    CERN Document Server

    Yao, B C; Wang, Z N; Wu, Y; Zhou, J H; Wu, H; Fan, M Q; Cao, X L; Zhang, W L; Chen, Y F; Li, Y R; Churkin, D; Turitsyn, S; Wong, C W

    2015-01-01

    Pulse generation often requires a stabilized cavity and its corresponding mode structure for initial phase-locking. Contrastingly, modeless cavity-free random lasers provide new possibilities for high quantum efficiency lasing that could potentially be widely tunable spectrally and temporally. Pulse generation in random lasers, however, has remained elusive since the discovery of modeless gain lasing. Here we report coherent pulse generation with modeless random lasers based on the unique polarization selectivity and broadband saturable absorption of monolayer graphene. Simultaneous temporal compression of cavity-free pulses are observed with such a polarization modulation, along with a broadly-tunable pulsewidth across two orders of magnitude down to 900 ps, a broadly-tunable repetition rate across three orders of magnitude up to 3 MHz, and a singly-polarized pulse train at 41 dB extinction ratio, about an order of magnitude larger than conventional pulsed fiber lasers. Moreover, our graphene-based pulse for...

  11. French Training

    CERN Multimedia

    Françoise Benz

    2003-01-01

    General and Professional French Courses The next session will take place: from 13 October to 19 December 2003. These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages or contact Mrs. Fontbonne: Tel. 72844. Writing Professional Documents in French This course is designed for people with a good level of spoken French. Duration: 30 hours Price: 660 CHF (for 8 students) For further information and registration, please consult our Web pages or contact Mrs. Fontbonne: Tel. 72844. Language Training Françoise Benz Tel.73127 language.training@cern.ch

  12. LANGUAGE TRAINING

    CERN Multimedia

    2003-01-01

    General and Professional French Courses The next session will take place: from 28 April to 27 June 2003. These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz or Mrs. Fontbonne: Tel. 73127, Mr. Liptow: Tel. 72957. Writing Professional Documents in French This course is designed for people with a good level of spoken French. Duration: 24 hours Price: 528 CHF (for 8 students) For further information and registration, please consult our Web pages: http://cern.ch/Training

  13. Slow and fast light via SBS in optical fibers for short pulses and broadband pump

    Science.gov (United States)

    Kalosha, V. P.; Chen, Liang; Bao, Xiaoyi

    2006-12-01

    Slow-light effect via stimulated Brillouin scattering (SBS) in single-mode optical fibers was considered for short probe pulses of nanosecond duration relevant to Gb/s data streams. Unlike recent estimations of delay versus pump based on steady-state small-signal approximation we have used numerical solution of three-wave equations describing SBS for a realistic fiber length. Both regimes of small signal and pump depletion (gain saturation) were considered. The physical origin of Stokes pulse distortion is revealed which is related to excitation of long-living acoustic field behind the pulse and prevents effective delay control by pump power increase at cw pumping. We have shown different slope of the gain-dependent delay for different pulse durations. Spectrally broadened pumping by multiple cw components, frequency-modulated pump and pulse train were studied for short pulses which allow to obtain large delay and suppress pulse distortion. In the pump-depletion regime of pumping by pulse train, both pulse delay and distortion decrease with increasing pump, and the pulse achieves advancement.

  14. Slow and fast light via SBS in optical fibers for short pulses and broadband pump.

    Science.gov (United States)

    Kalosha, V P; Chen, Liang; Bao, Xiaoyi

    2006-12-25

    Slow-light effect via stimulated Brillouin scattering (SBS) in single-mode optical fibers was considered for short probe pulses of nanosecond duration relevant to Gb/s data streams. Unlike recent estimations of delay versus pump based on steady-state small-signal approximation we have used numerical solution of three-wave equations describing SBS for a realistic fiber length. Both regimes of small signal and pump depletion (gain saturation) were considered. The physical origin of Stokes pulse distortion is revealed which is related to excitation of long-living acoustic field behind the pulse and prevents effective delay control by pump power increase at cw pumping. We have shown different slope of the gain-dependent delay for different pulse durations. Spectrally broadened pumping by multiple cw components, frequency-modulated pump and pulse train were studied for short pulses which allow to obtain large delay and suppress pulse distortion. In the pump-depletion regime of pumping by pulse train, both pulse delay and distortion decrease with increasing pump, and the pulse achieves advancement. PMID:19532161

  15. SNMR pulse sequence phase cycling

    Science.gov (United States)

    Walsh, David O; Grunewald, Elliot D

    2013-11-12

    Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

  16. Far Superior Control of LPI Is Achieved Using STUD Pulses than RPP, SSD, ISI or Pseudo-STUD Pulses

    Science.gov (United States)

    Hueller, Stefan; Afeyan, Bedros

    2011-10-01

    In a series of simulations using a modified and improved version of the code Harmony, we have compared the Brillouin backscattering reflectivity and ion acoustic wave generation in a STUD pulse (Spike Trains of Uneven Duration and Delay), vs more primitive beam smoothing techniques. The less effective techniques considered are RPP, SSD with realistic and exceedingly high bandwidths, ISI and pseudo-STUD pulses. In the latter, there is rapid temporal variation of the laser profile but always for the same RPP pattern in space. In STUD pulses, each laser spike samples a different RPP pattern. Orders of magnitude reduction in IAW generation and nonlinear reflection is observed in the case of STUD pulses compared to all other competitors. The effects of strong coupling, pump depletion and flow gradients are included. Work supported by a DOE NNSA SSAA grant and a DOE OFES Phase I SBIR grant.

  17. Pulse distortion in single-mode fibers. 3: Chirped pulses.

    Science.gov (United States)

    Marcuse, D

    1981-10-15

    The theory of pulse distortion in single-mode fibers is extended to include laser sources that suffer a linear wavelength sweep (chirp) during the duration of the pulse. The transmitted pulse is expressed as a Fourier integral whose spectral function is given by an analytical expression in closed form. The rms width of the transmitted pulse is also expressed in closed form. Numerical examples illustrate the influence of the chirp on the shape and rms width of the pulse. A somewhat paradoxical situation exists. A given input pulse can be made arbitrarily short by a sufficiently large amount of chirping, and, after a given fiber length, this chirped pulse returns to its original width. But at this particular distance an unchirped pulse would be only [equiation] times longer. Thus chirping can improve the rate of data transmission by only 40%.

  18. Pulse distortion in single-mode fibers. 3: Chirped pulses.

    Science.gov (United States)

    Marcuse, D

    1981-10-15

    The theory of pulse distortion in single-mode fibers is extended to include laser sources that suffer a linear wavelength sweep (chirp) during the duration of the pulse. The transmitted pulse is expressed as a Fourier integral whose spectral function is given by an analytical expression in closed form. The rms width of the transmitted pulse is also expressed in closed form. Numerical examples illustrate the influence of the chirp on the shape and rms width of the pulse. A somewhat paradoxical situation exists. A given input pulse can be made arbitrarily short by a sufficiently large amount of chirping, and, after a given fiber length, this chirped pulse returns to its original width. But at this particular distance an unchirped pulse would be only [equiation] times longer. Thus chirping can improve the rate of data transmission by only 40%. PMID:20372221

  19. Lectures on pulsed NMR

    Energy Technology Data Exchange (ETDEWEB)

    Pines, A.

    1986-09-01

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 55 figs.

  20. Downhole pulse tube refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

    1997-12-01

    This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

  1. Analog pulse processor

    Science.gov (United States)

    Wessendorf, Kurt O.; Kemper, Dale A.

    2003-06-03

    A very low power analog pulse processing system implemented as an ASIC useful for processing signals from radiation detectors, among other things. The system incorporates the functions of a charge sensitive amplifier, a shaping amplifier, a peak sample and hold circuit, and, optionally, an analog to digital converter and associated drivers.

  2. Hybrid Chirped Pulse Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, I; Barty, C P J

    2002-05-07

    We present a novel chirped pulse amplification method which combines optical parametric amplification and laser amplification. We have demonstrated this hybrid CPA concept with a combination of beta-barium borate and Ti:sapphire. High-efficiency, multi-terawatt compatible amplification is achieved without gain narrowing and without electro-optic modulators using a simple commercial pump laser.

  3. Power Trains.

    Science.gov (United States)

    Kukuk, Marvin; Mathis, Joe

    This curriculum guide is part of a series designed to teach students about diesel engines. The materials in this power trains guide apply to both on-road and off-road vehicles and include information about chain and belt drives used in tractors and combines. These instructional materials, containing nine units, are written in terms of student…

  4. Language training

    CERN Multimedia

    2006-01-01

    If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Departmental Secretariat or from your DTO (Departmental Training Officer). Applications will be accepted in the order in which they are received. General and Professional English Courses The next session will take place from beginning of October 2006 to beginning of February 2007 (3 weeks break at Christmas).These courses are open to all persons working on the CERN site and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Tessa Osborne, tel.16 23 40. Oral Expression The next session will take place from beginning of October 2006 to beginning of February 2007 (3 weeks break at Christmas).This course is intended for people with a good knowl...

  5. Language training

    CERN Multimedia

    Françoise Benz

    2006-01-01

    If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training'form available from your Departmental Secretariat or from your DTO (Departmental Training Officer). Applications will be accepted in the order in which they are received. General and Professional English Courses The next session will take place from beginning of October 2006 to beginning of February 2007 (3 weeks break at Christmas).These courses are open to all persons working on the CERN site and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Tessa Osborne, tel.16 23 40. Oral Expression The next session will take place from beginning of October 2006 to beginning of February 2007 (3 weeks break at Christmas).This course is intended for people with a goo...

  6. Language Training

    CERN Multimedia

    Françoise Benz

    2005-01-01

    If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Departmental Secretariat or from your DTO (Departmental Training Officer). Applications will be accepted in the order in which they are received. General and Professional English Courses The next session will take place: from end of September 2005 to middle of February 2006 (2/ 3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957. Oral Expression The next session will take place from end of September to December 2005. This course is intended for people with a good knowledge of English who want to practise and maintain the...

  7. Technical Training: Technical Training Seminar

    CERN Multimedia

    2004-01-01

    TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch Monday 9 February 2004 From 10:00 to 12:00 - IT Auditorium - bldg. 31, 3rd floor ANSOFT High-Frequency Seminar David Prestaux, Application Engineer, ANSOFT F-78535 BUC, France This Technical Training seminar will present two Ansoft application products: Ansoft HFSS and Ansoft Designer. Ansoft HFSS makes use of the Finite Element Method (FEM) to calculate field solutions from first principles. It can accurately predict all high-frequency behaviours such as dispersion, mode conversion, and losses due to materials and radiation. Ansoft Designer is a suite of design tools to fully integrate high-frequency, physics-based electromagnetic simulations into a seamless system-level simulation environment. Ansoft Designer uses a simple interface to give complete control over every design task, by a method allowing multiple solvers, Solver on Demand. • Introduction • Overview of the Ansoft Total solution • Ansoft HFSS 9...

  8. Fibre laser with a subterahertz repetition rate of ultrashort pulses in the telecom range

    Science.gov (United States)

    Andrianov, A. V.; Mylnikov, V. M.; Koptev, M. Yu; Muravyev, S. V.; Kim, A. V.

    2016-04-01

    We have investigated a new fibre laser configuration for the generation of ultrashort pulses at a repetition rate far exceeding the fundamental cavity frequency. The laser configuration includes a nonlinear amplifying mirror as an artificial saturable absorber for mode locking and a spectral comb filter for pulse separation stabilisation. Generation of trains and sequences of ultrashort pulses at a repetition rate tunable in the range 8 – 200 GHz has been demonstrated experimentally. The pulses generated by the laser have been shown to retain an ordered, equidistant structure on a nanosecond timescale.

  9. Information Fusing Recognition of Traditional Chinese Medicine (TCM) Pulse State Based on Stochastic Fuzzy Neural Network

    Institute of Scientific and Technical Information of China (English)

    QIN Jian; LIU Hong-jian; DENG Wei; WU Guo-zhen; CHEN Shu-qing; JING Ming-hua

    2005-01-01

    Based on the fuzzy characteristic of the pulse state and syndromes differentiation thinking mode of TCM, an information fusing recognition method of pulse states based on SFNN (Stochastic Fuzzy Neural Network) is presented in this paper. With the learning ability in parameters and structure, SFNN fuses the measurement information of three pulse-state sensors distributed in Cun, Guan,and Chi location of body for the pulse state recognition. The experimental results show that the percentage of correct recognition with new method is higher than that by single-data recognition one, with fewer off-line train numbers.

  10. Recent advances in pulse oximetry

    OpenAIRE

    Cannesson, Maxime; Talke, Pekka

    2009-01-01

    Conventional pulse oximetry uses two wavelengths of light (red and infrared) transmitted through a finger and a photodetector to analyze arterial hemoglobin oxygen saturation and pulse rate. Recent advances in pulse oximetry include: extended analysis of the photo plethysmographic waveform; use of multiple wavelengths of light to quantify methemoglobin, carboxyhemoglobin and total hemoglobin content in blood; and use of electronic processes to improve pulse oximeter signal processing during c...

  11. Sequentially pulsed traveling wave accelerator

    Science.gov (United States)

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  12. Bacterial inactivation using pulsed light

    OpenAIRE

    Elmnasser, Noura; Ritz, Magali; Leroi, Francoise; Orange, Nicole; Bakhrouf, Amina; Federighi, Michel

    2007-01-01

    Pulsed light is a new method intended for the decontamination of food surfaces using short, high frequency pulses of an intense broad spectrum. The effects of broad spectrum pulsed light on the survival of Listeria monocytogenes Scott A, Listeria monocytogenes CNL, Pseudomonas fluorescens MF37 and Photobacterium phosphoreum SF680 populations on agar and in a liquid medium were investigated during this study. The sterilisation system generated 1.5 J cm(-2) per pulse with eight lamps for 300 mu...

  13. Pulsed power for EMP simulators

    International Nuclear Information System (INIS)

    Simulation of nuclear weapons effects has been the main motivation for pulse power development in the US in the last decade. EMP simulation has been responsible for a major class of pulse power systems. A general survey of pulse power techniques is given, focusing of those particularly applicable for EMP simulation. This is followed by brief descriptions of several representative simulators

  14. Design of a pulse stacker

    International Nuclear Information System (INIS)

    A pulse stacker for the 100p sec short laser pulse produced by the Nd-glass laser VULCAN has been designed which has 150p sec between reflections. It was found that three or four plates (i.e. 6-8 surfaces) are needed to generate the approximately equal to 1 nsec pulse required. (U.K.)

  15. Ultrashort Pulses for Far-Field Nanoscopy

    CERN Document Server

    Maurer, Patrick; Romero-Isart, Oriol

    2016-01-01

    The Abbe diffraction limit prevents focusing monochromatic light in the far-field beyond a spot size half its wavelength. For microscopy purposes at the nanoscale, namely nanoscopy, such limit can be circumvented by either using near-fields, which are not diffraction-limited, or, in fluorescence nanoscopy, by manipulating bright and dark states of the fluorescent markers. Here we propose and analyze an alternative approach for far-field nanoscopy based on using coherent polychromatic light, that is, ultrashort pulses. Such pulses have spectral bandwidths comparable, and even larger in the attosecond regime, than a carrier optical frequency. We show that a train of ultrashort pulses can be used to excite markers with nanoscale resolution. In particular, we show that they can be focused to a spot size given by the wavelength associated to its spectral bandwidth and that they can excite a two-level marker with an optical transition. The excitation mechanism is non-conventional for two-level systems, as it relies...

  16. Hemifusion of cells using femtosecond laser pulses

    Science.gov (United States)

    Katchinskiy, Nir; Godbout, Roseline; Goez, Helly R.; Elezzabi, Abdulhakem Y.

    2015-03-01

    Attachment of single cells via hemifusion of cellular membranes using femtosecond laser pulses is reported in this manuscript. This is a method to attach single cells using sub-10 femtosecond laser pulses, with 800 nm central wavelength delivered from a Ti:Sapphire laser is described. A fluorescent dye, Calcein AM, was used to verify that the cell's cytoplasm did not migrate from a dyed cell to a non-dyed cell, in order to ascertain that the cells did not go through cell-fusion process. An optical tweezer was used in order to assess the mechanical integrity of the attached joint membranes. Hemifusion of cellular membranes was successful without initiating full cell fusion. Attachment efficiency of 95% was achieved, while the cells' viability was preserved. The attachment was performed via the delivery of one to two trains of sub-10 femtosecond laser pulses lasting 15 milliseconds each. An ultrafast reversible destabilization of the phospholipid molecules in the cellular membranes was induced due to a laser-induced ionization process. The inner phospholipid cell membrane remained intact during the attachment procedure, and cells' cytoplasm remained isolated from the surrounding medium. The unbounded inner phospholipid molecules bonded to the nearest free phospholipid molecule, forming a joint cellular membrane at the connection point. The cellular membrane hemifusion technique can potentially provide a platform for the creation of engineered tissue and cell cultures.

  17. Sports Training

    Science.gov (United States)

    1988-01-01

    Practitioners of martial arts have long seen a need for a precise method of measuring the power of a karate kick or a boxer's punch in training and competition. Impax sensor is a piezoelectric film less than one thousandth of an inch thick, yet extremely durable. They give out a voltage impulse when struck, the greater the force of impact, the higher the voltage. The impulse is transmitted to a compact electronics package where voltage is translated into a force-pounds reading shown on a digital display. Impax, manufactured by Impulse Technology, Inc. is used by martial arts instructors, practitioners, U.S. Olympic Committee Training Center, football blocking sleds, and boxers as well as police defensive tactics, providing a means of evaluating the performance of recruits.

  18. Language training

    CERN Multimedia

    2008-01-01

    General and Professional French Courses The next session will take place from 14 April to 27 June 2008. These courses are open to all persons working on the CERN site and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs Nathalie Dumeaux: Tel. 78144. Writing Professional Documents in French The next session will take place from 14 April to 27 June 2008. This course is designed for people with a good level of spoken French. Duration: 30 hours. Price: 660 CHF. For further information and registration, please consult our Web pages: http://cern.ch/Training or contact Mrs Nathalie Dumeaux: Tel. 78144.

  19. Language Training

    CERN Multimedia

    HR Department

    Permanence A "permanence" for language Training has been set up. If anyone has a question or requires information on any aspect of English or French training please come to our office 5 4-016 at the following times. Lucette Fournier - French courses Monday 13.30 - 15.30 Tuesday\t10.30 - 12.30 Tessa Osborne - English courses Wednesday\t12.00 - 14.00 Thursday\t11.00 - 13.00   New courses Specific English and French courses - Exam preparation/ We are now offering specific courses in English and French leading to a recognised external examination (e.g. Cambridge, DELF, DALF). If you are interested in following one of these courses and have at least an upper intermediate level of English or French, please enrol through the following link:  English courses French courses Or contact: Tessa Osborne 72957 (English courses) Lucette Fournier 73483 (French courses) Language Training Nathalie Dumeaux Tel. 78144 nathalie.dumeaux@cern.ch

  20. Language Training

    CERN Multimedia

    HR Department

    2009-01-01

    PermanenceA "permanence" for language Training has been set up. If anyone has a question or requires information on any aspect of English or French training please come to our office 5 4-016 at the following times. Lucette Fournier French courses Monday 13.30 - 15.30 Tuesday\t10.30 - 12.30 Tessa Osborne English courses Wednesday\t12.00 - 14.00 Thursday\t11.00 - 13.00 New courses Specific English and French courses - Exam preparation/ We are now offering specific courses in English and French leading to a recognised external examination (e.g. Cambridge, DELF and BULATS). If you are interested in following one of these courses and have at least an upper intermediate level of English or French, please enrol through the following link: http://English courses http://French courses Or contact: Tessa Osborne 72957 (English courses) Lucette Fournier 73483 (French courses) Language Training Nathalie Dumeaux Tel. 78144 mailto:nathalie.dumeaux@cern.ch

  1. Short pulse neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.

    2016-08-02

    Short pulse neutron generators are described herein. In a general embodiment, the short pulse neutron generator includes a Blumlein structure. The Blumlein structure includes a first conductive plate, a second conductive plate, a third conductive plate, at least one of an inductor or a resistor, a switch, and a dielectric material. The first conductive plate is positioned relative to the second conductive plate such that a gap separates these plates. A vacuum chamber is positioned in the gap, and an ion source is positioned to emit ions in the vacuum chamber. The third conductive plate is electrically grounded, and the switch is operable to electrically connect and disconnect the second conductive plate and the third conductive plate. The at least one of the resistor or the inductor is coupled to the first conductive plate and the second conductive plate.

  2. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim

    2011-12-01

    Full Text Available In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by welding dissimilar materials and allowing to welds light and stronger materials together. It can be used to weld metallic with non metallic materials to created mechanical lock on ceramics, polymers, rubbers and composites. It is green process; there is no heat, no radiation, no gas, no smoke and sparks, therefore the emissions are negligible.

  3. Pulsed fusion reactors

    International Nuclear Information System (INIS)

    This summer school specialized in examining specific fusion center systems. Papers on scientific feasibility are first presented: confinement of high-beta plasma, liners, plasma focus, compression and heating and the use of high power electron beams for thermonuclear reactors. As for technological feasibility, lectures were on the theta-pinch toroidal reactors, toroidal diffuse pinch, electrical engineering problems in pulsed magnetically confined reactors, neutral gas layer for heat removal, the conceptual design of a series of laser fusion power plants with ''Saturn'', implosion experiments and the problem of the targets, the high brightness lasers for plasma generation, and topping and bottoming cycles. Some problems common to pulsed reactors were examined: energy storage and transfer, thermomechanical and erosion effects in the first wall and blanket, the problems of tritium production, radiation damage and neutron activation in blankets, and the magnetic and inertial confinement

  4. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1989-01-01

    This is the fifth in a series of contracts and grants exploring the advanced particulate pollution control technology of electron beam precipitation. The chief goal of the current contract is to develop a laboratory scale electron beam precharger using a pulsed electric field to the proof-of-concept stage. Contract tasks leading to the achievement of this goal are generally divided up into two categories: tasks required to bring the Electron Beam Precipitator (EBP) test system up to an operational level for the contract work, and tasks concerning the actual experimental and analytical phase of the study. Not unexpectedly, the early portion of the contract duration will be devoted to the commissioning of the EBP and its many subsystems, while the latter portion will devote itself to testing the new pulsed electron beam precharger.

  5. Micro pulse laser radar

    Science.gov (United States)

    Spinhirne, James D. (Inventor)

    1993-01-01

    An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering is disclosed. The transmitter of the micro pulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited to optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that micropulse lider systems are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

  6. High-order harmonic noise-like pulsing of a passively mode-locked double-clad Er/Yb fibre ring laser

    Science.gov (United States)

    Pottiez, O.; Hernández-García, J. C.; Ibarra-Escamilla, B.; Kuzin, E. A.; Durán-Sánchez, M.; González-García, A.

    2014-11-01

    In this paper, we study noise-like pulse generation in a km-long fibre ring laser including a double-clad erbium-ytterbium fibre and passively mode-locked through nonlinear polarization evolution. Although single noise-like pulsing is only observed at moderate pump power, pulse energies as high as 120 nJ are reached in this regime. For higher pump power, the pulse splits into several noise-like pulses, which then rearrange into a stable and periodic pulse train. Harmonic mode locking from the 2nd to the 48th orders is readily obtained. At pump powers close to the damage threshold of the setup, much denser noise-like pulse trains are demonstrated, reaching harmonic orders beyond 1200 and repetition frequencies in excess of a quarter of a GHz. The mechanisms leading to noise-like pulse breaking and stable high-order harmonic mode locking are discussed.

  7. Measurement of pulse lengthening with pulse energy increase in picosecond Nd:YAG laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Cutolo, A.; Zeni, L.; Berardi, V.; Bruzzese, R.; Solimeno, S.; Spinelli, N.

    1989-03-15

    Taking advantage of a new technique, we have monitored the relative variations of time duration and mode size as a function of the pulse energy for 30-ps-long Nd:YAG laser pulses. In particular, by carrying out a statistical analysis, we have observed that the pulse time duration is an increasing function of the pulse energy, according to the theoretical modeling of passively mode-locked lasers. The measurements can be easily extended to the femtosecond regime.

  8. Pulsed laser microtomograph

    Science.gov (United States)

    Antonov, V. B.; Bonch-Bruevich, A. M.; Vasil'Ev, V. I.; Ionov, L. N.; Nikolaev, S. D.; Starobogatov, I. O.

    1994-12-01

    This paper describes a pulsed laser tomographic apparatus that has been implemented in practice and has a spatial resolution of 2-5 microns in the transverse direction and approximately 70 microns in the probe-radiation propagation direction. Experiments have been performed with model objects. Results have been obtained that confirm the possibility of early diagnosis of skin mycoses that cannot be diagnosed by existing methods.

  9. Twitter's visual pulse

    OpenAIRE

    Hare, Jonathon; Samangooei, Sina; Dupplaw, David; Lewis, Paul H.

    2013-01-01

    Millions of images are tweeted every day, yet very little research has looked at the non-textual aspect of social media communication. In this work we have developed a system to analyse streams of image data. In particular we explore trends in similar, related, evolving or even duplicated visual artefacts in the mass of tweeted image data — in short, we explore the visual pulse of Twitter.

  10. A volcano's pulse

    OpenAIRE

    Loughlin, Sue

    2010-01-01

    Before the 1995 Soufrière Hills eruption began, there had been seismic crises approximately every 30 years since the late 1890s; each crisis lasted months to years and involved thousands of small earthquakes. In 1935, some earthquakes were large enough to cause damage to buildings in the capital Plymouth and there was real concern that an eruption was imminent. These seismic crises were later interpreted as pulses of magma trying, but failing, to reach the surface. A final seis...

  11. Compact pulsed accelerator

    International Nuclear Information System (INIS)

    The formation of fast pulses from a current charged transmission line and opening switch is described. By employing a plasma focus as an opening switch and diode in the prototype device, a proton beam of peak energy 250 keV is produced. The time integrated energy spectrum of the beam is constructed from a Thomson spectrograph. Applications of this device as an inexpensive and portable charged particle accelerator are discussed. 7 refs., 5 figs., 1 tab

  12. Pulse Portraiture: Pulsar timing

    Science.gov (United States)

    Pennucci, Timothy T.; Demorest, Paul B.; Ransom, Scott M.

    2016-06-01

    Pulse Portraiture is a wideband pulsar timing code written in python. It uses an extension of the FFTFIT algorithm (Taylor 1992) to simultaneously measure a phase (TOA) and dispersion measure (DM). The code includes a Gaussian-component-based portrait modeling routine. The code uses the python interface to the pulsar data analysis package PSRCHIVE (ascl:1105.014) and also requires the non-linear least-squares minimization package lmfit (ascl:1606.014).

  13. STUCTURE OF PULSED BED

    Directory of Open Access Journals (Sweden)

    I. A. Bokun

    2014-01-01

    Full Text Available The structure of pulsed layer is proposed which can be suggested as a state of particulates that is blown by intermittent gas flow with speed which has the force to start material moving. Layer during one cycle is in a suspension, falling down and immobile state resulting in changes of particles arrangement as well as ways of gas flowing through layer. Moreover, it allows carrying out effective interphase heat exchange even adamant real granulation.The process of formation of impact flows is considered aw well as their influence on formation of air bubbles in pulsed layer. At startup of air blast the balance between the force of hydro-dynamic resistance is broken, on one side, and forces of gravity, particles inertia and their links with walls on the other side. The layer is transferred in the state of pulsed pseudo-fluidization, and presents gas-disperse mixture, inside of which impulse of pressure increasing is spreading to all sides as pressure waves (compression. These waves are the sources of impact flows’ formation, the force of which is two times more than during the stationary flow.The waves of pressure are divided into weak and strong ones depending on movement velocity within gas-disperse system. Weak waves are moving with a sound speed and strong ones in active phase of pulsed layer are moving over the speed of sound limit within gas-disperse system. The peculiarity of strong wave is that parameters of system (pressure, density and others are changing in discrete steps.The article describes the regime of layer’s falling down in the passive stage of cycle, which begins after finishing of gas impulse action. And suspension layer of moving up granular material is transferred in the state of falling resulting in change of the layer structure.

  14. Pulsed Superconductivity Acceleration

    CERN Document Server

    Liepe, M

    2000-01-01

    The design of the proposed linear collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities, operated in pulsed mode. Within the framework of an international collaboration the TESLA Test Facility (TTF) has been set up at DESY, providing the infrastructure for cavity R&D towards higher gradients. More than 60 nine-cell cavities were tested, accelerating gradients as high as 30 MV/m were measured. In the second production of TTF-cavities the average gradient was measured to be 24.7 MV/m. Two modules, each containing eight resonators, are presently used in the TTF-linac. These cavities are operated in pulsed mode: 0.8 ms constant gradient with up to 10 Hz repetitions rate. We will focus on two aspects: Firstly, the cavity fabrication and treatment is discussed, allowing to reach high gradients. Latest results of single cell cavities will be shown, going beyond 40 MV/m. Secondly, the pulsed mode operation of superconducting cavities is reviewed. This includes Lorentz force detuning, mechanic...

  15. Pulse radiolysis of gases

    International Nuclear Information System (INIS)

    The pulse radiolysis equipment and technique are described and its relevance to atmospheric chemistry is discussed. Pulse radiolysis of a number of different chemical systems have been used to check the validity of the proposed mechanisms: 1) The hydrogen atom yield in the pulse radiolysis of H2 was measured by four independent calibration techniques, using reactions of H with O2, C1NO, and HI. The H atom yield was compared with O2 yields in pure O2 and in O2/SF6 mixtures which lead to a value G(H) = 17.6. The rate constants at room temperature of several reactions were determined. 2) OH radical reactions with tetraalkyllead at room temperature and with ethane, methane, and a series of C1- and F-substituted methanes at 300-400 K were studied. Arrhenius parameters, A and Esub(a), were determined for several reactions. The lifetime of Pb(CH3)4 and Pb(C2H5)4 in ambient air is estimated. CF2C12 was found to be a very efficient third body, M, in the reaction OH + OH + M arrow H2O2 + M. 3) In the H2S systems the HS extinction coefficient at 3242 AA was determined to 9.5 x 102 cm-1 mol-1. Four rate constants at room temperature were determined. (author)

  16. Petawatt pulsed-power accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)

    2010-03-16

    A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

  17. Band-selective radiofrequency pulses

    Science.gov (United States)

    Geen, Helen; Freeman, Ray

    A theoretical treatment is given of the general problem of designing amplitude-modulated radiofrequency pulses that will excite a specified band of frequencies within a high-resolution NMR spectrum with uniform intensity and phase but with negligible excitation elsewhere. First a trial pulse envelope is defined in terms of a finite Fourier series and its frequency-domain profile calculated through the Bloch equations. The result is compared with the desired target profile to give a multidimensional error surface. The method of simulated annealing is then used to find the global minimum on this surface and the result refined by standard gradient-descent optimization. In this manner, a family of new shaped radio-frequency pulses, known as BURP ( band-selective, uniform response, pure-phase) pulses, has been created. These are of two classes—pulses that excite or invert z magnetization and those that act as general-rotation πr/2 or π pulses irrespective of the initial condition of the nuclear magnetization. It was found convenient to design the latter class as amplitude-modulated time-symmetric pulses. Tables of Fourier coefficients and pulse-shape ordinates are given for practical implementation of BURP pulses, together with the calculated frequency-domain responses and experimental verifications. Examples of the application of band-selective pulses in conventional and multidimensional spectroscopy are given. Pure-phase pulses of this type should also find applications in magnetic resonance imaging where refocusing schemes are undesirable.

  18. Quarter-wave pulse tube

    Science.gov (United States)

    Swift, G. W.; Gardner, D. L.; Backhaus, S. N.

    2011-10-01

    In high-power pulse-tube refrigerators, the pulse tube itself can be very long without too much dissipation of acoustic power on its walls. The pressure amplitude, the volume-flow-rate amplitude, and the time phase between them evolve significantly along a pulse tube that is about a quarter-wavelength long. Proper choice of length and area makes the oscillations at the ambient end of the long pulse tube optimal for driving a second, smaller pulse-tube refrigerator, thereby utilizing the acoustic power that would typically have been dissipated in the first pulse-tube refrigerator's orifice. Experiments show that little heat is carried from the ambient heat exchanger to the cold heat exchanger in such a long pulse tube, even though the oscillations are turbulent and even when the tube is compactly coiled.

  19. A training and educational tool for neutron coincidence measurements

    International Nuclear Information System (INIS)

    Neutron coincidence counting techniques are widely used for nuclear safeguards inspection. They are based on the detection of time correlated neutrons created from spontaneous or induced fission of plutonium and some other actinides. IAEA inspectors are trained to know and to use this technique, but it is not easy to illustrate and explain the basics of the neutron coincidence counting. The traditional shift registers or multiplicity counters give only multiplicity distributions and the singles, doubles and triples count rates. Using the list mode method for the recording and evaluation of neutron coincidence data makes it easier to teach this technique. List mode acquisition is a relatively new way to collect data in neutron coincidence counting. It is based on the recording of the follow-up times of neutron pulses originating from a neutron detector into a file. The recorded pulse train can be evaluated with special software after the measurement. Hardware and software for list mode neutron coincidence acquisition have been developed in the Institute of Isotopes and is called a Pulse Train Reader. A system called Virtual Source for replaying pulse trains registered with the list mode device has also been developed. The list mode device and the pulse train 're-player' together build a good educational tool for teaching the basics of neutron coincidence counting. Some features of the follow-up time, multiplicity and Rossi-alpha distributions can be well demonstrated by replaying artificially generated or pre-recorded pulse trains. The choice of real sources is stored on DVD. There is no need to transport and maintain real sources for the training. Virtual sources also give the possibility of investigating rare sources that trainees would not have access to otherwise. (authors)

  20. Technical Training: Technical Training Seminar

    CERN Multimedia

    2004-01-01

    TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch Tuesday 3 February 2004 From 09:00 to 13:30 - Training Centre Auditorium - bldg. 593, room 11 USB (Universal Serial Bus) CYPRESS Seminar Claudia Colombini, Field Application Engineer CYPRESS ActiveComp Electronic GmbH D-85077 MANCHING, Germany As a pioneer in USB, CYPRESS sets the standard for cost-effective solutions without sacrificing functionality, performance or reliability. Having shipped over 200 million USB devices, Cypress is the undisputed market leader and demonstrates unmatched USB expertise. With the industry's broadest selection of USB solutions, Cypress has the right silicon, software and support for every USB application, from Low-speed to High-Speed and USB On-The-Go (OTG). 9:00 - 10:30 Overview of USB systems. USB CYPRESS product overview. Peripherals: Low Speed, Full Speed, High Speed (1.1 and 2.0). Hub Solutions, Embedded Host Solutions, On-The-Go (OTG) and wireless USB. USB Development Tools (first part) 10:30 -...

  1. Single attosecond pulse from terahertz-assisted high-order harmonic generation

    CERN Document Server

    Balogh, Emeric; Dombi, Peter; Fulop, Jozsef A; Farkas, Gyozo; Hebling, Janos; Tosa, Valer; Varju, Katalin; 10.1103/PhysRevA.84.023806

    2011-01-01

    High-order harmonic generation by few-cycle 800 nm laser pulses in neon gas in the presence of a strong terahertz (THz) field is investigated numerically with propagation effects taken into account. Our calculations show that the combination of THz fields with up to 12 fs laser pulses can be an effective gating technique to generate single attosecond pulses. We show that in the presence of the strong THz field only a single attosecond burst can be phase matched, whereas radiation emitted during other half-cycles disappears during propagation. The cutoff is extended and a wide supercontinuum appears in the near-field spectra, extending the available spectral width for isolated attosecond pulse generation from 23 to 93 eV. We demonstrate that phase matching effects are responsible for the generation of isolated attosecond pulses, even in conditions when single atom response yields an attosecond pulse train.

  2. Single attosecond pulse from terahertz-assisted high-order harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Balogh, Emeric [Department of Optics and Quantum Electronics, University of Szeged, H-6701 Szeged (Hungary); Kovacs, Katalin [Department of Optics and Quantum Electronics, University of Szeged, H-6701 Szeged (Hungary); National Institute for R and D of Isotopic and Molecular Technologies, RO-400293 Cluj-Napoca (Romania); Dombi, Peter; Farkas, Gyozo [Research Institute for Solid State Physics and Optics, H-1525 Budapest (Hungary); Fulop, Jozsef A.; Hebling, Janos [Department of Experimental Physics, University of Pecs, H-7624 Pecs (Hungary); Tosa, Valer [National Institute for R and D of Isotopic and Molecular Technologies, RO-400293 Cluj-Napoca (Romania); Varju, Katalin [HAS Research Group on Laser Physics, University of Szeged, H-6701 Szeged (Hungary)

    2011-08-15

    High-order harmonic generation by few-cycle 800 nm laser pulses in neon gas in the presence of a strong terahertz (THz) field is investigated numerically with propagation effects taken into account. Our calculations show that the combination of THz fields with up to 12 fs laser pulses can be an effective gating technique to generate single attosecond pulses. We show that in the presence of the strong THz field only a single attosecond burst can be phase matched, whereas radiation emitted during other half cycles disappears during propagation. The cutoff is extended and a wide supercontinuum appears in the near-field spectra, extending the available spectral width for isolated attosecond pulse generation from 23 to 93 eV. We demonstrate that phase-matching effects are responsible for the generation of isolated attosecond pulses, even in conditions when single-atom response yields an attosecond pulse train.

  3. Media Training

    CERN Document Server

    CERN. Geneva

    2009-01-01

    With the LHC starting up soon, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. The training is open for everybody. Make sure you arrive early enough to get a seat - there are only 200 seats in the Globe. The session will also be webcast: http://webcast.cern.ch/

  4. ACADEMIC TRAINING

    CERN Multimedia

    Françoise Benz

    2002-01-01

    6, 7 May LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Decoding the Human Genome, Scientific basis and ethic and social aspects by S.E. Antonarakis and A. Mauron / Univ. of Geneva Decoding the Human genome is a very up-to-date topic, raising several questions besides purely scientific, in view of the two competing teams (public and private), the ethics of using the results, and the fact that the project went apparently faster and easier than expected. The lecture series will address the following chapters: Scientific basis and challenges, Ethical and social aspects of genomics. Academic Training Françoise Benz Tel. 73127

  5. SELECTING AND TRAINING THE TRAINING OFFICER.

    Science.gov (United States)

    TAYLOR, NANCY

    TO ACHIEVE THE OBJECTIVES OF TRAINING IN INDUSTRY--TECHNICAL AND LIBERAL EDUCATION, SPECIFIC JOB SKILLS, AND THE DEVELOPMENT OF ATTITUDES--THE TRAINING OFFICER MUST KNOW THE COMPANY WITHIN WHICH HE IS WORKING, AS WELL AS MANAGEMENT THEORY AND TRAINING METHODS. THE SELECTION OF TRAINING OFFICERS IS BASED ON A JOB SPECIFICATION, AN OUTGROWTH OF A…

  6. Coiled transmission line pulse generators

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Kenneth Fox (Columbia, MO)

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  7. French training

    CERN Multimedia

    2007-01-01

    The next session will take place from 29 January to 30 March 2007. These courses are open to all persons working on the CERN site, and their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: tel. 73127. Writing Professional Documents in French The next session will take place from 29 January to 30 March 2007. This course is designed for people with a good level of spoken French. Duration: 30 hours Price: 660 CHF (for 8 students) For further information and registration, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: tel. 73127. Writing Professional Documents in English The next session will take place from January to June 2007 (break at Easter). This course is designed for people with a good level of spoken English. Duration: 30 hours Price: 660 CHF (for 8 students) Timetable will be fixed after discussion with the students. For further information and registration, please consu...

  8. English Training

    CERN Multimedia

    2003-01-01

    General and Professional English Courses The next session will take place: from 03 March to 28 June 2003 (2 weeks break at Easter). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: tel.73127 or Mr. Liptow: tel.72957. Writing Professional Documents in English This course is designed for people with a good level of spoken English. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) For registration and further information, please consult our Web pages: http://cern.ch/Training or contact Mrs. Tessa Osborne: Tessa.Osborne@cern. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be approximately 8 participants in a class. Speaking activities will include discussions, meeting simulations, rol...

  9. Language Training

    CERN Document Server

    2003-01-01

    Formation en anglais Cours d'anglais général et professionnel La prochaine session se déroulera: du 06 octobre 2003 au 13 février 2004 (interruption de 3/4 semaines à Noël). Ces cours s'adressent à toute personne travaillant au CERN ainsi qu'à leur conjoint. Pour vous inscrire et voir tout le détail des cours proposés, consultez nos pages Web: http://cern.ch/Training Vous pouvez aussi contacter M. Liptow, tél. 72957. General and Professional English Courses The next session will take place: from 06 October 2003 to 13 February 2004 (3/4 weeks break at Christmas). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957. Writing Professional Documents in English This course is designed for people with a good level of...

  10. Language Training

    CERN Multimedia

    2003-01-01

    Formation en anglais Cours d'anglais général et professionnel La prochaine session se déroulera: du 06 octobre 2003 au 13 février 2004 (interruption de 3/4 semaines à Noël). Ces cours s'adressent à toute personne travaillant au CERN ainsi qu'à leur conjoint. Pour vous inscrire et voir tout le détail des cours proposés, consultez nos pages Web: http://cern.ch/Training Vous pouvez aussi contacter Mme Benz, tél. 73127 ou Mr Liptow, tél. 72957. General and Professional English Courses The next session will take place: from 06 October 2003 to 13 February 2004 (3/4 weeks break at Christmas). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: tel. 73127 or Mr. Liptow: tel. 72957. Writing Professional Documents in English This course is designed for people with a good level of spoken English. Duration: 20 hours (2 hours a week) Price: ...

  11. Language Training

    CERN Multimedia

    2003-01-01

    Formation en anglais Cours d'anglais général et professionnel La prochaine session se déroulera: du 06 octobre 2003 au 13 février 2004 (interruption de 3/4 semaines à Noël). Ces cours s'adressent à toute personne travaillant au CERN ainsi qu'à leur conjoint. Pour vous inscrire et voir tout le détail des cours proposés, consultez nos pages Web: http://cern.ch/Training Vous pouvez aussi contacter Mme Benz, tél. 73127 ou Mr Liptow, tél. 72957. General and Professional English Courses The next session will take place: from 06 October 2003 to 13 February 2004 (3/4 weeks break at Christmas). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: tel. 73127 or Mr. Liptow: tel. 72957. Writing Professional Documents in Engl...

  12. English Training

    CERN Multimedia

    2003-01-01

    General and Professional English Courses The next session will take place: from 03 March to 28 June 2003 (2 weeks break at Easter). These courses are open to all persons working on the Cern site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mrs. Benz: tel.73127 or Mr. Liptow: tel.72957. Writing Professional Documents in English This course is designed for people with a good level of spoken English. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) For registration and further information, please consult our Web pages: http://cern.ch/Training or contact Mrs. Tessa Osborne: Tessa.Osborne@cern. Oral Expression This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be approximately 8 participants in a class. Speaking activities will include discussions, meeting simulations, role-p...

  13. Versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    A description of the sequence of events and the decisions leading to the design of a versatile pulse programmer for pulsed NMR are presented. Background and application information is discussed in order that the reader might better understand the role of the pulse programmer in a NMR spectrometer. Various other design approaches are presented as a basis for comparison. Specifications for this design are proposed, the hardware implementation of the specifications is discussed, and the software operating system is presented

  14. Green Light Pulse Oximeter

    Energy Technology Data Exchange (ETDEWEB)

    Scharf, John Edward (Oldsmar, FL)

    1998-11-03

    A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

  15. Pulse front tilt measurement of femtosecond laser pulses

    Science.gov (United States)

    Dimitrov, Nikolay; Stoyanov, Lyubomir; Stefanov, Ivan; Dreischuh, Alexander; Hansinger, Peter; Paulus, Gerhard G.

    2016-07-01

    In this work we report experimental investigations of an intentionally introduced pulse front tilt on femtosecond laser pulses by using an inverted field correlator/interferometer. A reliable criterion for the precision in aligning (in principle) dispersionless systems for manipulating ultrashort pulses is developed, specifically including cases when the pulse front tilt is a result of a desired spatio-temporal coupling. The results obtained using two low-dispersion diffraction gratings are in good qualitative agreement with the data from a previously developed analytical model and from an independent interferometric measurement.

  16. Carrier-envelope Phase Drift Detection of Picosecond Pulses

    Directory of Open Access Journals (Sweden)

    Cormier E.

    2013-03-01

    Full Text Available A bandwidth-independent, linear and scalable method for carrier-envelope phase drift measurement demonstrated. Our experiments reveal that carrier-envelope phase drift of a picosecond pulse train can be directly obtained from the spectrally resolved interference pattern of a length-stabilized multiple-beam interferometer. The retrieved phase from the pattern correlates well with the strongly CEP-sensitive coupling signal between the frequency combs of the picosecond oscillator and an ultra-high finesse Fabry-Perot interferometer. Our results can lead to the generation of a robust CEP-stabilized seed pulse train for high resolution comb spectroscopy as well as to compact Compton X-ray and gamma-ray sources

  17. Can YAG screen accept LEReC bunch train?

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2016-05-18

    LEReC RF diagnostic beamline is supposed to accept 250 us long pulse trains of 1.6 MeV – 2.6 MeV (kinetic energy) electrons. This beamline is equipped with YAG profile monitor. Since we are interested in observing only the last macro bunch in the train, one of the possibilities is to install a fast kicker and a dedicated dump upstream of the YAG screen (and related diagnostics equipment). This approach is expensive and challenging from engineering point of view. Another possibility is to send the whole pulse train to the YAG screen and to use a fast gated camera (such as Imperex B0610 with trigger jitter under 60ns [1]) to observe the image from the last pulse only. In this paper we study the feasibility of the last approach.

  18. Can YAG screen accept LEReC bunch train?

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2016-05-18

    LEReC RF diagnostic beamline is supposed to accept 250 us long pulse trains of 1.6 MeV – 2.6 MeV (kinetic energy) electrons. This beamline is equipped with YAG profile monitor. Since we are interested in observing only the last macro bunch in the train, one of the possibilities is to install a fast kicker and a dedicated dump upstream of the YAG screen (and related diagnostics equipment). This approach is expensive and challenging from engineering point of view. Another possibility is to send the whole pulse train to the YAG screen and to use a fast gated camera (such as Imperex B0610 with trigger jitter under 60ns) to observe the image from the last pulse only. In this paper we study the feasibility of the last approach.

  19. COMPUTER BASED HEART PULSES MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Ali N. Hamoodi

    2013-05-01

    Full Text Available In this work the measurement and displays of blood oxygen saturation and pulse rate are investigated practically using computer.The analysis involves the variation in blood oxygen saturation ratio and pulse rate. The results obtained are compared with kontron pulse oximeter 7840 device. The value obtained for the same person pulse rate is approximately equal to that obtained by the konton pulse oximeter 7840 device. The sensor used in this work is the finger clip.The advantages of using computer over kontron pulse oximeter 7840 device is that the data of the patient can be saved in the computer for many years and also it can be display at any time so that the doctor get file contains all data for each patient. 

  20. Heat driven pulse pump

    Science.gov (United States)

    Benner, Steve M (Inventor); Martins, Mario S. (Inventor)

    2000-01-01

    A heat driven pulse pump includes a chamber having an inlet port, an outlet port, two check valves, a wick, and a heater. The chamber may include a plurality of grooves inside wall of the chamber. When heated within the chamber, a liquid to be pumped vaporizes and creates pressure head that expels the liquid through the outlet port. As liquid separating means, the wick, disposed within the chamber, is to allow, when saturated with the liquid, the passage of only liquid being forced by the pressure head in the chamber, preventing the vapor from exiting from the chamber through the outlet port. A plurality of grooves along the inside surface wall of the chamber can sustain the liquid, which is amount enough to produce vapor for the pressure head in the chamber. With only two simple moving parts, two check valves, the heat driven pulse pump can effectively function over the long lifetimes without maintenance or replacement. For continuous flow of the liquid to be pumped a plurality of pumps may be connected in parallel.

  1. Compensated pulsed alternator

    International Nuclear Information System (INIS)

    This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak output. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit

  2. Gravitational Pulse Astronomy

    CERN Document Server

    Gould, Andrew

    2010-01-01

    Thompson has recently argued that the Kozai mechanism is primarily responsible for driving white-dwarf binary mergers and so generating type Ia supernovae (SNe). If this is the case, the gravitational wave signal from these systems will be characterized by isolated repeating pulses that are well approximated by parabolic encounters. I show that standard Fourier-based searches would do a very poor job of digging these sources out of the noise, and propose a new type matched filter search, which can improve sensitivity by up to a factor ~30 relative to Fourier. If these eccentric binaries account for even a modest fraction of the observed SN rate, then there should be of order 1 pulse every 20 seconds coming from within 1 kpc, and there should be of order a thousand detectable sources in this same volume. I outline methods of identifying these sources both to remove this very pernicious background to other signals, and to find candidate SN Ia progenitors, and I sketch practical methods to find optical counterpa...

  3. Assembly delay line pulse generators

    CERN Multimedia

    1971-01-01

    Assembly of six of the ten delay line pulse generators that will power the ten kicker magnet modules. One modulator part contains two pulse generators. Capacitors, inductances, and voltage dividers are in the oil tank on the left. Triggered high-pressure spark gap switches are on the platforms on the right. High voltage pulse cables to the kicker magnet emerge under the spark gaps. In the centre background are the assembled master gaps.

  4. Programming Pulse Driven Quantum Computers

    OpenAIRE

    Lloyd, Seth

    1999-01-01

    Arrays of weakly-coupled quantum systems can be made to compute by subjecting them to a sequence of electromagnetic pulses of well-defined frequency and length. Such pulsed arrays are true quantum computers: bits can be placed in superpositions of 0 and 1, logical operations take place coherently, and dissipation is required only for error correction. Programming such computers is accomplished by selecting the proper sequence of pulses.

  5. ACADEMIC TRAINING

    CERN Multimedia

    Françoise Benz

    2002-01-01

    25, 26, 27, 28 February and 1st March from 11.00 to 12.00 hrs - Auditorium, bldg. 500 LECTURE SERIES Neutrino masses and oscillations by A. de Rujula / CERN-TH This course will not cover its subject in the customary way. The emphasis will be on the simple theoretical concepts (helicity, handedness, chirality, Majorana masses) which are obscure in most of the literature, and on the quantum mechanics of oscillations, that ALL books get wrong. Which, hopefully, will not deter me from discussing some of the most interesting results from the labs and from the cosmos. Academic Training Françoise Benz Secretariat Tel. 73127 francoise.benz@cern.ch

  6. English training

    CERN Multimedia

    2003-01-01

    You have a good level of English BUT... You still need to improve your speaking or You have problems writing professional documents Would you like to work in a small group on either of these areas? Then, the following courses are for you! Writing Professional Documents in English The aim of the course is for students to improve their professional writing. Participants will work on technical, scientific or administrative documents depending on the needs of the group. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) Oral Expression The emphasis will be on oral expression with necessary feed-back. Speaking activities will include discussions, meeting simulations, role-plays etc. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) For registration and further information, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957 / Mrs. Tessa Osborne: Tessa.Osborne@cern.ch.

  7. English Training

    CERN Multimedia

    2003-01-01

    You have a good level of English BUT... You still need to improve your speaking or You have problems writing professional documents Would you like to work in a small group on either of these areas? Then, the following courses are for you! Writing Professional Documents in English The aim of the course is for students to improve their professional writing. Participants will work on technical, scientific or administrative documents depending on the needs of the group. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) Oral Expression The emphasis will be on oral expression with necessary feed-back. Speaking activities will include discussions, meeting simulations, role-plays etc. Duration: 20 hours (2 hours a week) Price: 440 CHF (for 8 students) For registration and further information, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957 / Mrs. Tessa Osborne: Tessa.Osborne@cern.ch.

  8. A microsecond pulse radiolysis apparatus

    International Nuclear Information System (INIS)

    A pulse radiolysis system built up in Beijing Radiation Center was described. Using a 5 MeV scanning linac as the pulse radiation source, the system could provide a 2 microsecond width and 200 mA single pulse. The non-interrupt beam monitor was used to monitor the beam current. A kinetic spectrophotometer was chosen to detect the transient optical absorption. A BCM-80A single board computer system with a transient signal recording board was used to record and process the signal and to control the time sequencing. Several pulse radiolysis experiments were carried out in aqueous system and positive results were obtained

  9. Klystron pulse mudulator for linac

    International Nuclear Information System (INIS)

    A highly stable klystron pulse modulator is required in constructing a linac with good beam characteristics. The De-Qing circuit has been used conventionally to stabilize the output of a pulse modulator, but this method can achieve a stability of 1 percent at best, which is far larger than the targeted stability (less than 0.1 percent). The following three types of regulators are available to stabilize the D.C. power source of a pulse modulator: series regulator, shunt regulator and switching regulator. Advantages and disadvantages of these regulators are examined and the shunt regulator is selected because of its simple circuit structure and easy adjustment. The klystron pulse modulator has the features of being able to serve as a component of a large-power pulse klystron, being high in pulse stability (reproducibility), giving good pulse profiles (free from evershoot or undershoot), being small in size, etc. The klystron pulse modulator consists of a power source step-up transfermer, three-phase full-wave rectifying circuit, smoothing circuit, constant voltage control circuit, switching circuit, PFN circuit and pulse transformer. (Nogami, K.)

  10. Pulse oximetry in severe anaemia

    DEFF Research Database (Denmark)

    Ramsing, T; Rosenberg, J

    1992-01-01

    Measurement of arterial oxygen saturation by pulse oximetry was performed in two patients with acute and chronic anaemia (haemoglobin concentrations: 2.9 mmol/l (4.7 g/dl) and 1.9 mmol/l (3.0 g/dl), respectively) using a Radiometer OXI and a Nellcor N-200 pulse oximeter. The two oximeters read...... alternating different values in the two patients. In conclusion, pulse oximeters are able to give a value for oxygen saturation even at extreme anaemia, and when a high value is given, it possibly reflects arterial oxygen saturation. The value of pulse oximetry in severe anaemia is discussed....

  11. "Training Floors" and "Training Ceilings": Metonyms for Understanding Training Trends

    Science.gov (United States)

    Felstead, Alan; Jewson, Nick

    2014-01-01

    This article outlines a conceptual framework for mapping and understanding training trends. It uses the metonyms of floors and ceilings to distinguish between different types of training configurations. The argument is made that the ups and downs of employer reports of training activity are a crude basis on which to make judgements about the…

  12. Nuclear manpower training

    Energy Technology Data Exchange (ETDEWEB)

    Suh, In Suk; Lee, H. Y.; Joe, B. J.; Lee, S. H.; Lee, E. J.; Yoo, B. H.; Seo, K. W.; Lee, W. K.; Jun, H. I.; Yang, K. N.; Kim, Y. J.; Kim, I. H.; Kim, M. Y.; Ju, Y. C.; Hyun, H. Y.; Choi, I. G.; Hong, C. S.; Won, J. Y.; Nam, J. Y.; Lee, H. J.

    1997-01-01

    This report describes the annual results of training courses. the scope and contents are as follows: 1. Regional and interregional training courses 2. Training courses assisted by foreign experts 3. Training courses for nuclear industry personnel 4. Training courses for internal staff-members 5. Training courses under the law. This Nuclear Training Center executed the open-door training courses for 2,400 engineers/scientists from the regulatory body, nuclear industries, research institutes and other related organizations by means of offering 51 training courses during the fiscal year 1996. (author). 23 refs.

  13. Nuclear manpower training

    International Nuclear Information System (INIS)

    This report describes the annual results of training courses. the scope and contents are as follows: 1. Regional and interregional training courses 2. Training courses assisted by foreign experts 3. Training courses for nuclear industry personnel 4. Training courses for internal staff-members 5. Training courses under the law. This Nuclear Training Center executed the open-door training courses for 2,400 engineers/scientists from the regulatory body, nuclear industries, research institutes and other related organizations by means of offering 51 training courses during the fiscal year 1996. (author). 23 refs

  14. Theoretical Studies of the Output Pulse with Variation of the Pumping Pulse for RF Excited CO2 Pulsed Waveguide Laser

    Institute of Scientific and Technical Information of China (English)

    A Rauf; ZHOU Wei; XIN Jian-guo

    2006-01-01

    The behavior of a RF-excited waveguide CO2 laser in the pulse regime is studied theoretically. The output pulse evolution is studied by applying three types of pulses namely the square, sine and the triangular ones as the excitation pulses. The frequency dependence behavior of the output pulse is also presented.

  15. 2011 Training Industry Report

    Science.gov (United States)

    Training, 2011

    2011-01-01

    This article presents "Training" magazine's exclusive analysis of the U.S. training industry, featuring 2011 training expenditures, budgetary allocations, delivery methods, and training priorities. Now in its 30th year, The Industry Report is recognized as the training industry's most trusted source of data on budgets, staffing, and programs. This…

  16. Training from the Start.

    Science.gov (United States)

    Cocheu, Ted

    1990-01-01

    The time to plan training is in the research and development stage of a new product. Seven major steps are online training, process validation, skills certification, development of manufacturing training instructions, skills verification, transfer training, and offline training and certification. (SK)

  17. Management Training in Retailing.

    Science.gov (United States)

    Veness, C. Rosina

    Intended for prospective members of the new Distributive Industrial Training Board in Great Britain, this training guide concentrates on managerial functions in retailing; the selection of trainees; the planning of in-company and external training programs; scheduling and continuity of training; roles of training personnel; and the use of various…

  18. On the applicability of arbitrarily shaped nanosecond laser pulses for high-quality, high-efficiency micromachining

    Science.gov (United States)

    Eiselen, Sasia; Riedel, Sebastian; Schmidt, Michael

    2014-05-01

    Progressive developments in temporal shaping of short laser pulses offer entirely new approaches at influence and investigate laser-matter-interactions. Commonly used parameters for describing the behavior of short or ultrashort pulses or pulse trains are fluence and intensity. However, fluence does not imply any information about the temporal behavior of energy input during specific pulse duration τ while using the pulse intensity as describing parameter is more meaningful. Nevertheless it still is an averaging over pulse duration and no change in intensity can be determined if the temporal pulse shape changes within a certain combination of pulse duration and pulse energy. Using a flexible programmable MOPA fiber laser experimental studies on the impact of temporal energy distribution within one single laser pulse in micro machining applications were therefore carried out. With this laser source a direct modulation of the temporal pulse shape in the nanosecond regime can easily be controlled. Experiments were carried out with moved as well as with un-moved beam resulting in areas and dimples respectively drilling holes. The presented results clearly show that any averaging over pulse duration results in missing information about time-dependent interactions but can at the same time lead to significant differences in ablation results. Thus, resulting surface roughness Sa can be decreased up to 25 % when changing the pulse shape at constant parameters of fluence and pulse peak power at a pulse duration of 30 ns. It can be observed that the combination of an intensity peak and a lower edge within one pulse can lead to increasing ablation efficiency as well as higher ablation quality compared to the commonly used Gaussian-like temporal pulse shape.

  19. Pulse-shaping strategies in short-pulse fiber amplifiers

    International Nuclear Information System (INIS)

    Ultrashort pulse lasers are an important tool in scientific and industrial applications. However, many applications are demanding higher average powers from these ultrashort pulse sources. This can be achieved by combining direct diode pumping with novel gain media designs. In particular, ultrashort pulse fiber lasers are now delivering average powers in the kW range. However, the design of fiber lasers, producing pulses with high peak-powers, is challenging due to the impact of nonlinear effects. To significantly reduce these detrimental effects in ultrashort pulse fiber amplifers, the combination of chirped pulse amplification (CPA) and large mode area fibers is employed. Using these methods, the pulse energy of fiber lasers has been steadily increasing for the past few years. Recently, a fiber-based CPA-system has been demonstrated which produces pulse energies of around 1 mJ. However, both the stretching and the enlargement of the mode area are limited, and therefore, the impact of nonlinearity is still noticed in systems employing such devices. The aim of this thesis is the analysis of CPA-systems operated beyond the conventional nonlinear limit, which corresponds to accumulated nonlinear phase-shifts around 1 rad. This includes a detailed discussion of the influence of the nonlinear effect self-phase modulation on the output pulse of CPA-systems. An analytical model is presented. Emphasis is placed on the design of novel concepts to control the impact of self-phase modulation. Pulse-shaping is regarded as a powerful tool to accomplish this goal. Novel methods to control the impact of SPM are experimentally demonstrated. The design of these concepts is based on the theoretical findings. Both amplitude- and phase-shaping are studied. Model-based phase-shaping is implemented in a state-of-the-art fiber CPA-system. The influence of the polarization state is also highlighted. Additionally, existing techniques and recent advances are put into context. (orig.)

  20. Pulse-shaping strategies in short-pulse fiber amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Schimpf, Damian Nikolaus

    2010-02-09

    Ultrashort pulse lasers are an important tool in scientific and industrial applications. However, many applications are demanding higher average powers from these ultrashort pulse sources. This can be achieved by combining direct diode pumping with novel gain media designs. In particular, ultrashort pulse fiber lasers are now delivering average powers in the kW range. However, the design of fiber lasers, producing pulses with high peak-powers, is challenging due to the impact of nonlinear effects. To significantly reduce these detrimental effects in ultrashort pulse fiber amplifers, the combination of chirped pulse amplification (CPA) and large mode area fibers is employed. Using these methods, the pulse energy of fiber lasers has been steadily increasing for the past few years. Recently, a fiber-based CPA-system has been demonstrated which produces pulse energies of around 1 mJ. However, both the stretching and the enlargement of the mode area are limited, and therefore, the impact of nonlinearity is still noticed in systems employing such devices. The aim of this thesis is the analysis of CPA-systems operated beyond the conventional nonlinear limit, which corresponds to accumulated nonlinear phase-shifts around 1 rad. This includes a detailed discussion of the influence of the nonlinear effect self-phase modulation on the output pulse of CPA-systems. An analytical model is presented. Emphasis is placed on the design of novel concepts to control the impact of self-phase modulation. Pulse-shaping is regarded as a powerful tool to accomplish this goal. Novel methods to control the impact of SPM are experimentally demonstrated. The design of these concepts is based on the theoretical findings. Both amplitude- and phase-shaping are studied. Model-based phase-shaping is implemented in a state-of-the-art fiber CPA-system. The influence of the polarization state is also highlighted. Additionally, existing techniques and recent advances are put into context. (orig.)

  1. Capacitor discharge pulse analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary

    2013-08-01

    Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.

  2. Spaced cognitive training promotes training transfer

    Directory of Open Access Journals (Sweden)

    Zuowei eWang

    2014-04-01

    Full Text Available Cognitive training studies yield wildly inconsistent results. One dimension on which studies vary is the scheduling of training sessions (Morrison & Chein, 2011. In this study, we systematically address whether or not spacing of practice influences training and transfer. We randomly assigned 115 fifth grade children to an active control group or one of four training groups who received working memory training based on a running span task (Zhao et al., 2011. All groups received the same total amount of training: 20 sessions of training with 60 trials for an average of 20 minutes per session. The training was spread across 2 days, 5 days, 10 days, or 20 days. The active control group received 20-minute sessions of math instruction for 20 sessions. Before and after training participants in all five groups performed a single transfer test that assessed fluid intelligence, the Raven's Progressive Matrices Test. Overall, participants in all four training groups improved significantly on the training task (at least partially, as reflected by increased speed. More importantly, the only training group to show significant improvement on the Raven's was the group who had the greatest amount of spacing (20 days group during training and improvement in this group was significantly higher than that of the control group.

  3. Artificial neural network based pulse shape analysis in cryogenic detectors for rare event searches

    International Nuclear Information System (INIS)

    We present a method based on an Artificial Neural Network for a pulse shape analysis in cryogenic detectors. To train the neural network a huge amount of pulses with known properties are necessary. Therefore, a data-driven simulation used to generate these sets is explained. Furthermore, these simulations allow detailed studies, especially of the cut efficiency and the signal purity of the developed cut. First results are presented and compared with the performance of alternative algorithms.

  4. Ultrashort Q-switched pulses from a passively mode-locked distributed Bragg reflector semiconductor laser

    OpenAIRE

    Strain, M; Zanola, M.; Mezosi, G.; Sorel, M.

    2012-01-01

    A compact semiconductor mode-locked laser (MLL) is presented that demonstrates strong passive Q-switched mode-locking over a wide range of drive conditions. The Q-switched frequency is tunable between 1 and 4 GHz for mode-locked pulses widths around 3.5 ps. The maximum ratio of peak to average power of the pulse-train is >120, greatly exceeding that of similarly sized passively MLLs.

  5. Sensitivity to pulse phase duration in cochlear implant listeners: Effects of stimulation mode

    OpenAIRE

    Chatterjee, Monita; Kulkarni, Aditya M.

    2014-01-01

    The objective of this study was to investigate charge-integration at threshold by cochlear implant listeners using pulse train stimuli in different stimulation modes (monopolar, bipolar, tripolar). The results partially confirmed and extended the findings of previous studies conducted in animal models showing that charge-integration depends on the stimulation mode. The primary overall finding was that threshold vs pulse phase duration functions had steeper slopes in monopolar m...

  6. Artificial neural network based pulse shape analysis in cryogenic detectors for rare event searches

    Energy Technology Data Exchange (ETDEWEB)

    Zoeller, Andreas [Physik Department E15, Technische Universitaet Muenchen, 85748 Garching (Germany); Collaboration: CRESST-Collaboration

    2015-07-01

    We present a method based on an Artificial Neural Network for a pulse shape analysis in cryogenic detectors. To train the neural network a huge amount of pulses with known properties are necessary. Therefore, a data-driven simulation used to generate these sets is explained. Furthermore, these simulations allow detailed studies, especially of the cut efficiency and the signal purity of the developed cut. First results are presented and compared with the performance of alternative algorithms.

  7. The chirped-pulse free-electron laser: Final technical report, September 1987--October 1988

    International Nuclear Information System (INIS)

    This is the final report of a theoretical and numerical investigation into the operation of pulsed free-electron lasers in which the electron energy depends on the time of injection into the wiggler. Such energy ''chirping'' over each of a train of electron micropulses injected into an FEL oscillator is expected to give rise to a laser pulse inside the optical resonator with a chirped carrier frequency ω/sub s/(/tau/)

  8. All-fiber high-average power nanosecond-pulsed master-oscillator power amplifier at 2  μm with mJ-level pulse energy.

    Science.gov (United States)

    Wang, Xiong; Jin, Xiaoxi; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2016-03-10

    We present a high-power nanosecond-pulsed Tm-doped fiber amplifier at 1.971 μm based on a master-oscillator power amplifier (MOPA) configuration. When the repetition rate is 500 kHz and the pulse width is 63.3 ns, the average power reaches 238 W, the peak power reaches 7.06 kW, and the pulse energy is 0.477 mJ. When the pulse train's repetition rate is 300 kHz with a pulse width of 63.7 ns, the average power reaches 197 W, the peak power reaches 9.73 kW, and the pulse energy is 0.66 mJ. When the pulse train's repetition rate is 200 kHz with a pulse width of 58.2 ns, the average power reaches 150 W, the peak power reaches 12.1 kW, and the pulse energy is 0.749 mJ. The spectral linewidths of the pulse trains are 0.15, 0.14, and 0.10 nm for 500 kHz repetition rate, 300 kHz repetition rate, and 200 kHz repetition rate, respectively. To the best of our knowledge, this is the first demonstration of high-power nanosecond-pulsed MOPA at 2 μm with the maximum average power reaching 238 W, the maximum peak power reaching 12.1 kW, and the maximum pulse energy reaching 0.749 mJ.

  9. Nonlinear Femtosecond Pulse Reshaping in Waveguide Arrays

    OpenAIRE

    Darren D. Hudson; Shish, Kimberlee; Schibli, Thomas R.; Kutz, J. Nathan; Christodoulides, Demetrios N.; Morandotti, Roberto; Cundiff, Steven T.

    2008-01-01

    We observe nonlinear pulse reshaping of femtosecond pulses in a waveguide array due to coupling between waveguides. Amplified pulses from a mode-locked fiber laser are coupled to an AlGaAs core waveguide array structure. The observed power-dependent pulse reshaping agrees with theory, including shortening of the pulse in the central waveguide.

  10. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy

    2011-09-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  11. Language training

    CERN Document Server

    2006-01-01

    General and Professional English Courses The next session will take place from beginning of October 2006 to beginning of February 2007 (3 weeks break at Christmas).These courses are open to all persons working on the CERN site and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Tessa Osborne, tel.16 23 40. Oral Expression The next session will take place from beginning of October 2006 to beginning of February 2007 (3 weeks break at Christmas).This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be a maximum of 10 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc., depending on the needs of the students. Duration: 30 hours (2 hours a week) Price: 660 CHF (for a minimum of 8 students). Writing Professional Documents in English The next ses...

  12. Language Training

    CERN Document Server

    Françoise Benz

    2005-01-01

    General and Professional English Courses The next session will take place: from end of September 2005 to middle of February 2006 (2/ 3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957. Oral Expression in English The next session will take place from end of September to December 2005. This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be a maximum of 10 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 20 hours Price: 440 CHF (for a minimum of 8 students) Writing Professional Documents in English The next session will take place from end of September 2005 to middle of Febr...

  13. Language training

    CERN Multimedia

    Françoise Benz

    2005-01-01

    General and Professional English Courses The next session will take place: from end of September 2005 to middle of February 2006 (2/ 3 weeks break at Christmas). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957. Oral Expression in English The next session will take place from end of September to December 2005. This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be a maximum of 10 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 20 hours Price: 440 CHF (for a minimum of 8 students) Writing Professional Documents in English The next session will take place from end of September 2005 to middle of Feb...

  14. Language training

    CERN Document Server

    2007-01-01

    General and Professional English Courses The next session will take place from 26 February or 5 March to end of June 2007 (1/2 weeks break at Easter). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Françoise Benz, tel. 73127. Oral Expression The next session will take place from 26 February or 5 March to end of June 2007 (1/2 weeks break at Easter). This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be a maximum of 10 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 30 hours Price: 660 CHF (for a minimum of 8 students). Writing Professional Documents in English The next session will take place from 26 February or...

  15. Language training

    CERN Multimedia

    2007-01-01

    General and Professional English Courses The next session will take place: from 26 February or 5 March to end of June 2007 (1/2 weeks break at Easter). These courses are open to all persons working on the CERN site, and to their spouses. For registration and further information on the courses, please consult our Web pages: http://cern.ch/Training or contact Françoise Benz, tel. 73127. Oral Expression The next session will take place from 26 February or 5 March to end of June 2007 (1/2 weeks break at Easter). This course is intended for people with a good knowledge of English who want to practise and maintain their speaking skills while extending their vocabulary. There will be a maximum of 10 participants in a class. Speaking activities will include discussions, meeting simulations, role-plays etc. depending on the needs of the students. Duration: 30 hours Price: 660 CHF (for a minimum of 8 students). Writing Professional Documents in English The next session will take place from 26 February or 5 M...

  16. Development of reliable 70 T pulsed magnets

    Science.gov (United States)

    Lagutin, A.; Rosseel, K.; Herlach, F.; Vanacken, J.; Bruynseraede, Y.

    2003-12-01

    A capacitor-driven pulsed magnet coil has been designed to generate fields in the 70-75 T range, with a life expectancy of at least 100 pulses, thus qualifying as a '75 T class user magnet'. The bore is 10 mm and the rise time used in our experiments is 4 ms. The coil consists of two coaxial sections: the inner section, where stresses are highest, is made with CuNb microcomposite wire and optimized Zylon reinforcement; the outer section is made with soft copper and glass fibre composite. In the inner section, the stress in each layer is self-contained, while the stresses induced in the outer section are transmitted to a thick shell made from steel and carbon fibre composite. The cross section of the copper wires is adjusted to redistribute the heating evenly between the inner and the outer section. Another innovative design feature is a system for axial compression that can be easily retightened during coil training. Two nearly identical coils were manufactured and tested to 72 T this is a limit imposed due to overheating when using our 10 kV, 0.5 MJ capacitor bank (at an energy of 380 kJ). At 75 T, the calculated von Mises stress in the Zylon composite is 2.6 GPa, well below the UTS of more than 3 GPa, and the CuNb wire is still in an elastic state.

  17. Pulse oximetry for perioperative monitoring

    DEFF Research Database (Denmark)

    Pedersen, Tom; Nicholson, Amanda; Hovhannisyan, Karen;

    2014-01-01

    of perioperative monitoring with pulse oximetry to clearly identify adverse outcomes that might be prevented or improved by its use.The following hypotheses were tested.1. Use of pulse oximetry is associated with improvement in the detection and treatment of hypoxaemia.2. Early detection and treatment...... of perioperative monitoring with pulse oximetry. A single study in general surgery showed that postoperative complications occurred in 10% of participants in the oximetry group and in 9.4% of those in the control group. No statistically significant differences in cardiovascular, respiratory, neurological...... after cardiothoracic surgery; however, routine continuous monitoring did not reduce transfer to an ICU and did not decrease overall mortality. AUTHORS' CONCLUSIONS: These studies confirmed that pulse oximetry can detect hypoxaemia and related events. However, we found no evidence that pulse oximetry...

  18. Pre-earthquake Magnetic Pulses

    CERN Document Server

    Scoville, John; Freund, Friedemann

    2014-01-01

    A semiconductor model of rocks is shown to describe unipolar magnetic pulses, a phenomenon that has been observed prior to earthquakes. These pulses are observable because their extremely long wavelength allows them to pass through the Earth's crust. Interestingly, the source of these pulses may be triangulated to pinpoint locations where stress is building deep within the crust. We couple a semiconductor drift-diffusion model to a magnetic field in order to describe the electromagnetic effects associated with electrical currents flowing within rocks. The resulting system of equations is solved numerically and it is seen that a volume of rock may act as a diode that produces transient currents when it switches bias. These unidirectional currents are expected to produce transient unipolar magnetic pulses similar in form, amplitude, and duration to those observed before earthquakes, and this suggests that the pulses could be the result of geophysical semiconductor processes.

  19. Staff training in organisation

    OpenAIRE

    Vomáčka, Štěpán

    2012-01-01

    This thesis is focused to areas of staff training in organization. The first part summarize general problems of staff training as a part of human resources management and concepts are explained such as motivation to education, human recources management, staff training methods, analyses of staff training needs, methods of development needs identification, staff training planning, corporate staff training, e-learning and evaluation of personnel development results. The second part of this thes...

  20. Experimental investigation of a novel microchip laser producing synchronized dual-frequency laser pulse with an 85 GHz interval

    Science.gov (United States)

    Hu, M.; An, R. D.; Zhang, H.; Huang, Q. F.; Ge, J. H.

    2013-01-01

    A novel self-Q-switched microchip laser is introduced, which can produce synchronized dual-frequency laser pulse trains. By adopting a prepump mechanism, as well as shifting the gain curve and resonance wavelengths, the relative gains of π and σ polarization modes are adjusted, which offers an effective way to finely synchronize the laser pulses. By employing a 0.9 mm length monolithic cavity, a pair of synchronized pulse trains with a frequency separation of 85 GHz (0.32 nm) is achieved, which nearly approaches the gain bandwidth of the laser medium. Another separated cavity with a length of 2.8 mm operates in the same way for further investigation of microwave generation. A radiofrequency signal with frequency of 26.565 GHz is achieved by beat-noting of the synchronized laser pulse trains with 0.1 nm wavelength separation.

  1. Dynamic training devices in CRM training

    Science.gov (United States)

    Lawver, J.

    1984-01-01

    Pilot training effectiveness and flying safety of a seasonal tour flight company are described. The change from single pilot to two pilot operated twin otters is examined. The use of the ATC 810 training device, its possibilities and training capacity is outlined. Problem areas which may arise, emergency system and pilot/passenger interaction are analyzed.

  2. 脉冲序列控制电流断续模式Buck变换器的动力学建模与边界碰撞分岔%Dynamical modeling and border collision bifurcation in pulse train controlled discontinuous conduction mode buck converter

    Institute of Scientific and Technical Information of China (English)

    沙金; 包伯成; 许建平; 高玉

    2012-01-01

    According to the charge variation of output capacitor in a switching cycle, the output voltage variation in a switching cycle can be obtained, from which an approximate discrete-time model of pulse train (PT) controlled buck converter operating in discontinuous conduction mode (DCM) is established. Based on the model, the border-collision bifurcations of the PT controlled DCM buck converter with the variations of the load resistance and the input voltage are studied. By constructing the corresponding iterative map curves, the stabilities of the fixed points, formed by the orbits of period-l, period-2, period-3 and so on, are analyzed, and the mechanisms of border-collision bifurcations of the converter under different operation states are revealed. The analysis results indicate that with the variation of parameters, the PT controlled DCM buck converter always operates in different periodic states, in which the change of the operation mode with periodic state is caused by the border-collision bifurcation and the lyapunov exponent is always less than zero. By using PSIM circuit simulation software, the time domain waveforms and phase portraits under different load resistances are obtained. Experimental results are provided to verify the correctnesses of theoretical analyses and circuit simulations and the feasibility of dynamical modelling.%通过建立一个开关周期内输出电容电荷变化量对应的输出电压变化量,建立了工作于电感电流断续模式(discontinuousconductionmode,DCM)的脉冲序列(pulsetrain,VT)控制Buck变换器的近似离散时间模型,研究了负载电阻及输入电压变化时PT控制DCMBuck变换器的边界碰撞分岔行为.通过构造相应的迭代映射曲线,分别分析了不同负载电阻时阿控制DCMBuck变换器的周期1、周期2和周期3运行轨迹的不动点稳定性,揭示了PT控制DCMBuck变换器在不同周期态时的边界碰撞分岔的形成机理.研究结

  3. Temporal Behaviour of Harmonics from One-Dimensional H2+ in an UltrashortLaser Pulse

    Institute of Scientific and Technical Information of China (English)

    屈卫星; 李儒新; 徐至展; 夏宇兴; 甘明龙

    2001-01-01

    With the method of wavelet transform, we consider the temporal behaviour of high-order harmonic generationfrom one-dimensional H2+ exposed to an ultrashort laser pulse with a duration of tens of femtoseconds. The results, which are calculated by numerically solving the corresponding time-dependent Schrodinger equation with the split-operator method in the non-Born-Oppenheimer approach, show that: (1) the high-order harmonics in the cut-off range emitted as a train of pulses have better coherence than those in the plateau; (2) the harmonics are emitted early in time when the intensity of the laser pulse increases.

  4. High-order-harmonic generation driven by pulses with angular spatial chirp

    Science.gov (United States)

    Hernández-García, Carlos; Jaron-Becker, Agnieszka; Hickstein, Daniel D.; Becker, Andreas; Durfee, Charles G.

    2016-02-01

    We present and analyze a technique to drive high-order harmonics by laser pulses with an angular spatial chirp. Results of our numerical simulations show that each harmonic is emitted with an angular chirp which scales inversely with the harmonic order and leads to additional control of the spatial and temporal resolution of the spectrum. In particular, the use of angular chirp leads to separation of the harmonics in two dimensions where (i) high spectral resolution can be achieved and (ii) the temporal periodicity of the harmonic pulse trains can be controlled. We show that this technique does not require carrier-envelope-phase stabilization when using few-cycle laser pulses.

  5. Fractional high-harmonic combs by attosecond-precision split-spectrum pulse control

    Directory of Open Access Journals (Sweden)

    Laux Martin

    2013-03-01

    Full Text Available Few-cycle laser fields enable pulse-shaping control of high-order harmonic generation by time delaying variable broadband spectral sections. We report the experimental generation of fractional (noninteger high-harmonic combs by the controlled interference of two attosecond pulse trains. Additionally the energy of the high harmonics is strongly tuned with the relative time delay. We quantify the tuning to directly result from the controlled variation of the instantaneous laser frequency at the shaped driver pulse intensity maximum.

  6. Pulse on pulse: modulation and signification in Rafael Lozano-Hemmer's Pulse Room

    Directory of Open Access Journals (Sweden)

    Merete Carlson

    2012-06-01

    Full Text Available This article investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006 by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy of the visitor's beating heart to the flashing of a fragile light bulb, thereby transforming each light bulb into a register of individual life. But at the same time the flashing light bulbs together produce a chaotically flickering light environment composed by various layers of repetitive rhythms, a vibrant and pulsating “room”. Hence, the visitor in Pulse Room is invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic “rhythm of life” and instants of pure material processuality (flickering light bulbs; polyrhythmic layers. Taking our point of departure in a discussion of Gilles Deleuze's concepts of modulation and signaletic material in relation to electronic media, we examine how the complex orchestration of pulsation between signification and material modulation produces a multilayered sense of time and space that is central to the sensory experience of Pulse Room as a whole. Pulse Room is, at the very same time, a relational subject–object intimacy and an all-encompassing immersive environment modulating continuously in real space-time.

  7. Generation of ultrashort radiation pulses by injection locking a regenerative free-electron-laser amplifier

    International Nuclear Information System (INIS)

    We demonstrate how a steady-state train of ultrashort radiation pulses can be produced utilizing a new free-electron laser (FEL) configuration, the injection-locked regenerative klystron amplifier (IRKA). This configuration consists of two elements: (1) a prebuncher, which microbunches the electron beams at the desired output wavelength, and (2) a multipass FEL operated at a very small cavity desynchronism and below the lasing threshold, in the regime of regenerative amplification. The regenerative amplifier is driven by the microbunched electron beam, so that the pulse-to-pulse stability is provided by the pre-buncher. The broad amplification bandwidth of this regenerative amplifier enables generation of ultrashort pulses, much shorter than a slippage length, with high efficiency. The IRKA configuration can produce such ultra-short radiation pulses while avoiding the chaotic dynamics that limits conventional FEL performance. copyright 1997 The American Physical Society

  8. Development of real-time pulse shaping technology in solid-state lasers

    International Nuclear Information System (INIS)

    We developed real-time pulse shaping technology in solid-state lasers for special cutting and welding applications. Our real-time pulse shaping unit has the capabilities of 20 steps variation in laser intensity, 200 steps in laser pulse width, and 16 pulse shape patterns with MOSFET Pulse Width Modulation method. Also, we improved our previous 250 W class Nd:YAG laser system by using this new technology. Many optical parts were localized and lowered much in cost. Only few parts were imported and almost 90% in cost were localized. Also, to accellerate the commercialization by the joint company, the training and transfer of technology were pursued in the joint participation in design and assembly by company researchers from the early stage. Two Nd:YAG lasers have been assembled and will be tested in industrial manufacturing processes to prove the capability of developed Nd:YAG laser with potential users. (Author)

  9. Generation of 10 GHz 2ps Short Laser Pulses Using an Electroabsorption Modulator and Two-Stage Compression

    Institute of Scientific and Technical Information of China (English)

    HUO Li; LOU Cai-Yun; GAO Yi-Zhi

    2005-01-01

    @@ A short pulse generator based on a commercially available bulk material electroabsorption modulator was experimentally demonstrated. By optimizing the length of the dispersion compensation fibre, nearly transform limited pulse was generated. There are a 2-ps-pulsed train with a timing jitter of 650 fs and a repetition rate of 10 GHz obtained with two-stage nonlinear compression. The quality of the pulse was further verified by 4 × 10 Gbit/s optical time-division-multiplexed communication system experiment in which a low demultiplexing power penalty of 0.3 dB was achieved.

  10. Pulse Detonation Engine Modeled

    Science.gov (United States)

    Paxson, Daniel E.

    2001-01-01

    Pulse Detonation Engine Technology is currently being investigated at Glenn for both airbreathing and rocket propulsion applications. The potential for both mechanical simplicity and high efficiency due to the inherent near-constant-volume combustion process, may make Pulse Detonation Engines (PDE's) well suited for a number of mission profiles. Assessment of PDE cycles requires a simulation capability that is both fast and accurate. It should capture the essential physics of the system, yet run at speeds that allow parametric analysis. A quasi-one-dimensional, computational-fluid-dynamics-based simulation has been developed that may meet these requirements. The Euler equations of mass, momentum, and energy have been used along with a single reactive species transport equation, and submodels to account for dominant loss mechanisms (e.g., viscous losses, heat transfer, and valving) to successfully simulate PDE cycles. A high-resolution numerical integration scheme was chosen to capture the discontinuities associated with detonation, and robust boundary condition procedures were incorporated to accommodate flow reversals that may arise during a given cycle. The accompanying graphs compare experimentally measured and computed performance over a range of operating conditions for a particular PDE. Experimental data were supplied by Fred Schauer and Jeff Stutrud from the Air Force Research Laboratory at Wright-Patterson AFB and by Royce Bradley from Innovative Scientific Solutions, Inc. The left graph shows thrust and specific impulse, Isp, as functions of equivalence ratio for a PDE cycle in which the tube is completely filled with a detonable hydrogen/air mixture. The right graph shows thrust and specific impulse as functions of the fraction of the tube that is filled with a stoichiometric mixture of hydrogen and air. For both figures, the operating frequency was 16 Hz. The agreement between measured and computed values is quite good, both in terms of trend and

  11. Technical Training: Technical Training Seminar

    CERN Multimedia

    2004-01-01

    Tuesday 30 March TECHNICAL TRAINING SEMINAR From 9:00 to 12:00 and from 13:00 to 16:00 hrs - Council Chamber, Salle B, Salle des Pas Perdus National Instruments (NI) on Tour 2004 Claudia Jüngel, Evrem Yarkin, Joel Clerc, Hervé Baour / NATIONAL INSTRUMENTS The special event NI on Tour 2004, run in Germany, Austria and Switzerland, will be at CERN on March 30. Technical seminars and free introductory courses will be offered all day long in the Council Chamber, Salle B, and Salle des Pas Perdus (buildings 61 and 503). Technical conferences: 09:00 - 12:00 Data acquisition systems on PCs. Industrial measurement and control techniques. 13:00 - 16:00 Advanced LabVIEW software and PXI instrumentation. Measuring instruments and system components for teststand automation. Introductory courses: 09:00 - 12:00 DIAdem: Data analysis and presentation 13:00 - 16:00 Data acquisition with LabVIEW Language: English and French Free special seminar. Registration is recommended with National Instruments Switzerland (please sp...

  12. Technical Training: Technical Training Seminar

    CERN Multimedia

    2004-01-01

    Tuesday 30 March TECHNICAL TRAINING SEMINAR From 9:00 to 12:00 and from 13:00 to 16:00 hrs - Council Chamber, Salle B, Salle des Pas Perdus National Instruments (NI) on Tour 2004 Claudia Jüngel, Evrem Yarkin, Joel Clerc, Hervé Baour / NATIONAL INSTRUMENTS The special event NI on Tour 2004, run in Germany, Austria and Switzerland, will be at CERN on March 30. Technical seminars and free introductory courses will be offered all day long in the Council Chamber, Salle B, and Salle des Pas Perdus (buildings 61 and 503). Technical conferences: 09:00 - 12:00 Data acquisition systems on PCs. Industrial measurement and control techniques. 13:00 - 16:00 Advanced LabVIEW software and PXI instrumentation. Measuring instruments and system components for teststand automation. Introductory courses: 09:00 - 12:00 DIAdem: Data analysis and presentation 13:00 - 16:00 Data acquisition with LabVIEW Language: English and French Free special seminar. Registration is recommended with National Instruments Swi...

  13. Pulse source requirements for OTDM systems

    DEFF Research Database (Denmark)

    Clausen, Anders; Poulsen, Henrik Nørskov; Oxenløwe, Leif Katsuo;

    2003-01-01

    A simulation model for investigating the impact of incoherent crosstalk due to pulse tail overlapping is proposed. Requirements to pulse width and pulse tail extinction ratio introducing a maximum of 1 dB penalty is extracted.......A simulation model for investigating the impact of incoherent crosstalk due to pulse tail overlapping is proposed. Requirements to pulse width and pulse tail extinction ratio introducing a maximum of 1 dB penalty is extracted....

  14. Bomb pulse biology

    Energy Technology Data Exchange (ETDEWEB)

    Falso, Miranda J. Sarachine [Center for Accelerator Mass Spectrometry, Mail Stop L-397, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States); Buchholz, Bruce A., E-mail: buchholz2@llnl.gov [Center for Accelerator Mass Spectrometry, Mail Stop L-397, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States)

    2013-01-15

    The past decade has seen an explosion in use of the {sup 14}C bomb pulse to do fundamental cell biology. Studies in the 1960s used decay counting to measure tissue turnover when the atmospheric {sup 14}C/C concentration was changing rapidly. Today bulk tissue measurements are of marginal interest since most of the carbon in the tissue resides in proteins, lipids and carbohydrates that turn over rapidly. Specific cell types with specialized functions are the focus of cell turnover investigations. Tissue samples need to be fresh or frozen. Fixed or preserved samples contain petroleum-derived carbon that has not been successfully removed. Cell or nuclear surface markers are used to sort specific cell types, typically by fluorescence-activated cell sorting (FACS). Specific biomolecules need to be isolated with high purity and accelerator mass spectrometry (AMS) measurements must accommodate samples that generally contain less than 40 {mu}g of carbon. Furthermore, all separations must not add carbon to the sample. Independent means such as UV absorbance must be used to confirm molecule purity. Approaches for separating specific proteins and DNA and combating contamination of undesired molecules are described.

  15. Magnetic Alignment of Pulsed Solenoids Using the Pulsed Wire Method

    International Nuclear Information System (INIS)

    A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5 T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 (micro)m. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression experiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 pm of the induction cell axis has been demonstrated.

  16. Magnetic Alignment of Pulsed Solenoids Using the Pulsed Wire Method

    Energy Technology Data Exchange (ETDEWEB)

    Arbelaez, D.; Madur, A.; Lipton, T.M.; Waldron, W.L.; Kwan, J.W.

    2011-04-01

    A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5 T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 {micro}m. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression experiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beam has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 pm of the induction cell axis has been demonstrated.

  17. Giant pulses in Millisecond Pulsars

    CERN Document Server

    Joshi, B C; Lyne, A G; McLaughlin, M; Stairs, I H

    2003-01-01

    Giant pulses (GPs), occasional individual pulses with an intensity 100 times the average intensity, have been detected in four pulsars todate. Their origin is not well understood, but studies suggest a connection between the strength of magnetic field at the light cylinder B_lc and the existence of GPs. Here, we report on detection of significant Large Amplitude Pulses (LAPs) in two more pulsars with high values of B_lc, PSRs J0218+4232 and B1957+20, observed using Giant Meterwave Radio Telescope (GMRT).

  18. Pulsed ultrasonic stir welding method

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  19. Hyper dispersion pulse compressor for chirped pulse amplification systems

    Energy Technology Data Exchange (ETDEWEB)

    Barty, Christopher P. J. (Hayward, CA)

    2011-11-29

    A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.

  20. Dance combined with magnetic pulse stimulates the ability of walk and balance in elder people

    OpenAIRE

    Lu, Tao; Song, Qing-Hua; Xu, Rong-Mei; Guo, Yan-Hua; Wang, Feng; Hu, Jian-Ping; Wang, Yi(Centre for Theoretical Cosmology, DAMTP, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA U.K.); Zhang, Li-Yan

    2015-01-01

    Objective: Observe the treatment effect on elderly people’s waling and balance ability under the stimulation and intervention of waving dance combined with magnetic pulse. Method: 96 elderly people are Involved in the research and the random number table method is divided into observation group and control group; there are 48 people in each group. The control group on the basis of routine daily activities increase waving dance for training treatment; the observation group take training treatm...

  1. Characteristics of preliminary breakdown pulses in positive ground flashes during summer thunderstorms in Sweden

    OpenAIRE

    Dalina Johari; Vernon Cooray; Mahbubur Rahman; Pasan Hettiarachchi; Mohd Muzafar Ismail

    2016-01-01

    This paper presents the characteristics of the preliminary breakdown pulses (PBP) in 51 positive ground flashes recorded during 2014 summer thunderstorms in Sweden. Electric field measurements were conducted remotely using a broadband antenna system (up to 100 MHz) for a recording length of 1 s with 200 ms trigger time. In the analysis, PBP trains were observed in 86% of the cases. Based on the number of trains preceding the first return stroke, the PBP were classified into single and multipl...

  2. Pulse-to-pulse Diagnostics at High Reprate

    Science.gov (United States)

    Green, Bertram; Kovalev, Sergey; Golz, Torsten; Stojanovich, Nikola; Fisher, Alan; Kampfrath, Tobias; Gensch, Michael

    2016-03-01

    Femtosecond level diagnostic and control of sub-picosecond electron bunches is an important topic in modern accelerator research. At the same time new linear electron accelerators based on quasi-CW SRF technology will be the drivers of many future 4th Generation lightsources such as X-ray free electron lasers. A high duty cycle, high stability and online pulse to pulse diagnostic at these new accelerators are crucial ingredients to the success of these large scale facilities. A novel THz based online monitor concept is presented that has the potential to give access to pulse to pulse information on bunch form, arrival time and energy at high repetition rate and down to sub pC charges. We furthermore show experimentally that pulse to pulse arrival time measurements can be used to perform pump-probe experiments with a temporal resolution in the few-fs regime and an exceptional dynamic range. Our scheme has been tested at the superradiant test facility TELBE, but can be readily transferred to other SRF accelerator driven photon sources, such as X-FELs.

  3. Nuclear manpower training

    Energy Technology Data Exchange (ETDEWEB)

    Suh, In Suk; Lee, H. Y.; Lee, E. J.; Yang, K. N.; Jun, H. R.; Seo, K. W.; Lee, S. H.; Kim, Y. J.; Kim, I. H.; Joe, B. J.; Koh, Y. S.; Yoo, B. H.; Kim, M. Y.; Ju, Y. C.; Hyun, H. U.; Choi, I. K.; Hong, C. S.; Won, J. Y.; Nam, J. Y.; Lee, H. J

    1997-12-01

    This report describes the annual results of training courses. The scope and contents are as follows: 1. Education program development of nuclear field 2. International training courses for foreigners 3. Training courses for industry personnel 4. Training courses for R and D staff-members 5. Training courses under the law. The nuclear training center executed 65 training courses for 2,700 engineers/ scientists from the regulatory body, nuclear industries, research institutes and other related organizations during the fiscal year 1997. (author). 18 refs., 3 tabs.

  4. Nuclear manpower training

    International Nuclear Information System (INIS)

    This report describes the annual results of training courses. The scope and contents are as follows: 1. Education program development of nuclear field 2. International training courses for foreigners 3. Training courses for industry personnel 4. Training courses for R and D staff-members 5. Training courses under the law. The nuclear training center executed 65 training courses for 2,700 engineers/ scientists from the regulatory body, nuclear industries, research institutes and other related organizations during the fiscal year 1997. (author). 18 refs., 3 tabs

  5. Training propositional reasoning.

    Science.gov (United States)

    Klauer, K C; Meiser, T; Naumer, B

    2000-08-01

    Two experiments compared the effects of four training conditions on propositional reasoning. A syntactic training demonstrated formal derivations, in an abstract semantic training the standard truth-table definitions of logical connectives were explained, and a domain-specific semantic training provided thematic contexts for the premises of the reasoning task. In a control training, an inductive reasoning task was practised. In line with the account by mental models, both kinds of semantic training were significantly more effective than the control and the syntactic training, whereas there were no significant differences between the control and the syntactic training, nor between the two kinds of semantic training. Experiment 2 replicated this pattern of effects using a different set of syntactic and domain-specific training conditions. PMID:10994233

  6. Training evaluation final report

    Science.gov (United States)

    Sepulveda, Jose A.

    1992-01-01

    In the area of management training, 'evaluation' refers both to the specific evaluation instrument used to determine whether a training effort was considered effective, and to the procedures followed to evaluate specific training requests. This report recommends to evaluate new training requests in the same way new procurement or new projects are evaluated. This includes examining training requests from the perspective of KSC goals and objectives, and determining expected ROI of proposed training program (does training result in improved productivity, through savings of time, improved outputs, and/or personnel reduction?). To determine whether a specific training course is effective, a statement of what constitutes 'good performance' is required. The user (NOT the Training Branch) must define what is 'required level of performance'. This 'model' will be the basis for the design and development of an objective, performance-based, training evaluation instrument.

  7. Pulsed Corona for Sustainable Technology

    International Nuclear Information System (INIS)

    Highly active coronas with a peak power of up to 25 MW p/m corona wire and kJ/liter energy densities in the streamer channels can be produced by pulsed power. Since the voltage pulses are short, full breakdown does not occur even though the discharge currents are hundreds of Amperes. A matched pulsed power source can deposit up to 80% of its electrical energy into such a controlled discharge. Reliable and efficient sources characterized by 100 kV,150 ns wide pulses at 1000 Hz have passed 400 hours of operation. The area of applications is growing: VOC control, hot gas cleanup, water and air purification and sterilization. (author)

  8. Rapidly pulsed helium droplet source

    Energy Technology Data Exchange (ETDEWEB)

    Pentlehner, Dominik; Riechers, Ricarda; Dick, Bernhard; Slenczka, Alkwin [Institute for Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg (Germany); Even, Uzi; Lavie, Nachum; Brown, Raviv; Luria, Kfir [Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv (Israel)

    2009-04-15

    A pulsed valve connected to a closed-cycle cryostat was optimized for producing helium droplets. The pulsed droplet beam appeared with a bimodal size distribution. The leading part of the pulse consists of droplets suitable for doping with molecules. The average size of this part can be varied between 10{sup 4} and 10{sup 6} helium atoms, and the width of the distribution is smaller as compared to a continuous-flow droplet source. The system has been tested in a single pulse mode and at repetition rates of up to 500 Hz with almost constant intensity. The droplet density was found to be increased by more than an order of magnitude as compared to a continuous-flow droplet source.

  9. Next generation Chirped Pulse Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nees, J.; Biswal, S.; Mourou, G. [Univ. Michigan, Center for Ultrafast Optical Science, Ann Arbor, MI (United States); Nishimura, Akihiko; Takuma, Hiroshi

    1998-03-01

    The limiting factors of Chirped Pulse Amplification (CPA) are discussed and experimental results of CPA in Yb:glass regenerative amplifier are given. Scaling of Yb:glass to the petawatt level is briefly discussed. (author)

  10. Generation of atto-second pulses on relativistic mirror plasma

    International Nuclear Information System (INIS)

    When an ultra intense femtosecond laser (I > 1016 W.cm-2) with high contrast is focused on a solid target, the laser field at focus is high enough to completely ionize the target surface during the rising edge of the laser pulse and form a plasma. This plasma is so dense (the electron density is of the order of hundred times the critical density) that it completely reflects the incident laser beam in the specular direction: this is the so-called 'plasma mirror'. When laser intensity becomes very high, the non-linear response of the plasma mirror to the laser field periodically deforms the incident electric field leading to high harmonic generation in the reflected beam. In the temporal domain this harmonic spectrum is associated to a train of atto-second pulses. The goals of my work were to get a better comprehension of the properties of harmonic beams produced on plasma mirrors and design new methods to control theses properties, notably in order to produce isolated atto-second pulses instead of trains. Initially, we imagined and modeled the first realistic technique to generate isolated atto-second on plasma mirrors. This brand new approach is based on a totally new physical effect: 'the atto-second lighthouse effect'. Its principle consists in sending the atto-second pulses of the train in different directions and selects one of these pulses by putting a slit in the far field. Despite its simplicity, this technique is very general and applies to any high harmonic generation mechanism. Moreover, the atto-second lighthouse effect has many other applications (e.g in metrology). In particular, it paves the way to atto-second pump-probe experiments. Then, we studied the spatial properties of these harmonics, whose control and characterization are crucial if one wants to use this source in future application experiments. For instance, we need to control very precisely the harmonic beam divergence in order to achieve the atto-second lighthouse effect and get isolated

  11. Artistic Representation with Pulsed Holography

    Science.gov (United States)

    Ishii, S.

    2013-02-01

    This thesis describes artistic representation through pulsed holography. One of the prevalent practical problems in making holograms is object movement. Any movement of the object or film, including movement caused by acoustic vibration, has the same fatal results. One way of reducing the chance of movement is by ensuring that the exposure is very quick; using a pulsed laser can fulfill this objective. The attractiveness of using pulsed laser is based on the variety of materials or objects that can be recorded (e.g., liquid material or instantaneous scene of a moving object). One of the most interesting points about pulsed holograms is that some reconstructed images present us with completely different views of the real world. For example, the holographic image of liquid material does not appear fluid; it looks like a piece of hard glass that would produce a sharp sound upon tapping. In everyday life, we are unfamiliar with such an instantaneous scene. On the other hand, soft-textured materials such as a feather or wool differ from liquids when observed through holography. Using a pulsed hologram, we can sense the soft touch of the object or material with the help of realistic three-dimensional (3-D) images. The images allow us to realize the sense of touch in a way that resembles touching real objects. I had the opportunity to use a pulsed ruby laser soon after I started to work in the field of holography in 1979. Since then, I have made pulsed holograms of activities, including pouring water, breaking eggs, blowing soap bubbles, and scattering feathers and popcorn. I have also created holographic art with materials and objects, such as silk fiber, fabric, balloons, glass, flowers, and even the human body. Whenever I create art, I like to present the spectator with a new experience in perception. Therefore, I would like to introduce my experimental artwork through those pulsed holograms.

  12. Pulsed feedback defers cellular differentiation.

    Directory of Open Access Journals (Sweden)

    Joe H Levine

    2012-01-01

    Full Text Available Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable "polyphasic" positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a "timer" that operates over timescales much longer than a cell cycle.

  13. Optical pulses, lasers, measuring techniques

    CERN Document Server

    Früngel, Frank B A

    1965-01-01

    High Speed Pulse Technology: Volume II: Optical Pulses - Lasers - Measuring Techniques focuses on the theoretical and engineering problems that result from the capacitor discharge technique.This book is organized into three main topics: light flash production from a capacitive energy storage; signal transmission and ranging systems by capacitor discharges and lasers; and impulse measuring technique. This text specifically discusses the air spark under atmospheric conditions, industrial equipment for laser flashing, and claims for light transmitting system. The application of light impulse sign

  14. Pulsed ultrasonic stir welding system

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  15. Artistic Representation with Pulsed Holography

    International Nuclear Information System (INIS)

    This thesis describes artistic representation through pulsed holography. One of the prevalent practical problems in making holograms is object movement. Any movement of the object or film, including movement caused by acoustic vibration, has the same fatal results. One way of reducing the chance of movement is by ensuring that the exposure is very quick; using a pulsed laser can fulfill this objective. The attractiveness of using pulsed laser is based on the variety of materials or objects that can be recorded (e.g., liquid material or instantaneous scene of a moving object). One of the most interesting points about pulsed holograms is that some reconstructed images present us with completely different views of the real world. For example, the holographic image of liquid material does not appear fluid; it looks like a piece of hard glass that would produce a sharp sound upon tapping. In everyday life, we are unfamiliar with such an instantaneous scene. On the other hand, soft-textured materials such as a feather or wool differ from liquids when observed through holography. Using a pulsed hologram, we can sense the soft touch of the object or material with the help of realistic three-dimensional (3-D) images. The images allow us to realize the sense of touch in a way that resembles touching real objects. I had the opportunity to use a pulsed ruby laser soon after I started to work in the field of holography in 1979. Since then, I have made pulsed holograms of activities, including pouring water, breaking eggs, blowing soap bubbles, and scattering feathers and popcorn. I have also created holographic art with materials and objects, such as silk fiber, fabric, balloons, glass, flowers, and even the human body. Whenever I create art, I like to present the spectator with a new experience in perception. Therefore, I would like to introduce my experimental artwork through those pulsed holograms.

  16. Video Processor for Transponder Pulses

    Science.gov (United States)

    Byrne, F.

    1986-01-01

    Circuit detects interrogation signals from air-traffic-control station and determines whether transponder of airplane should respond. Circuit examines relative magnitudes of first two pulses in three-pulse sequence of interrogation signal. On basis of relative magnitudes, circuit decides whether main lobe of interrogating radar beam is received (response should be generated) or only side lobe received (and interrogation ignored). Circuit simple and inexpensive.

  17. Pulsed power molten salt battery

    Science.gov (United States)

    Argade, Shyam D.

    1992-02-01

    It was concluded that carbon cathodes with chlorine work well. Lithium alloy chlorine at 450 C, 1 atm given high power capability, high energy density, DC + pulsing yields 600 pulses, no initial peak, and can go to red heat without burn-up. Electrochemical performance at the cell and cell stack level out under demanding test regime. Engineering and full prototype development for advancing this technology is warranted.

  18. Training In Diversity Management

    Directory of Open Access Journals (Sweden)

    Sonja Treven

    2011-07-01

    Full Text Available The labor force all around the world is becoming increasingly diverse. Thus, organizations that can manage employee diversity effectively gain a competitive advantage. In such organizations diversity training is a necessity. Diversity training helps managers understand and value individual differences and develop strong diagnostic skills. The paper explores various approaches to training, like awareness-based and skill-based diversity training. A special attention to potential problems that may occur in the process of diversity training is given.

  19. The Toulouse pulsed magnet facility

    International Nuclear Information System (INIS)

    The 'Laboratoire National des Champs Magnetiques Pulses' (LNCMP) is an international user facility providing access to pulsed magnetic fields up to and beyond 60 T. The laboratory disposes of 10 magnet stations equipped with long-pulse magnets operating in the 35-60 T range and a short-pulse system reaching magnetic fields in excess of 70 T. The experimental infrastructure includes various high and low-temperature systems ranging from ordinary flow-type cryostats to dilution refrigerators reaching 50 mK, as well as different types of high-pressure cells. Experimental techniques include magnetization, transport, luminescence, IR-spectroscopy and polarimetry. The LNCMP pursues an extensive in-house research program focussing on all technological and scientific aspects of pulsed magnetic fields. Recent technical developments include the implementation of 60 T rapid-cooling coils, an 80 T prototype, a pulsed dipole magnet for optical investigations of dilute matter and a transportable horizontal access magnet for small angle x-ray scattering experiments. Scientific activities cover a variety of domains, including correlated electron systems, magnetism, semiconductors and nanoscience

  20. Autogenic training as a therapy for adjustment disorder in adolescents

    Directory of Open Access Journals (Sweden)

    Jojić Boris R.

    2005-01-01

    Full Text Available INTRODUCTION Autogenic training is a widespread technique used in psychotherapy. The British school of autogenic training cites a large list of diseases, health states, and life changes, in which autogenic training can be of help. We wanted to explore the application of autogenic training as a therapy for adjustment disorder in adolescents. The sample consisted of a homogeneous group of 31 individuals, with an average age of 17.3±0.2 years, who were diagnosed with adjustment disorder, F 43.2, in accordance with ICD 10 search criteria. OBJECTIVE The aim of our work was to figure out the influence of autogenic training on adjustment disorder, through biophysical and biochemical indicators, and to research the efficacy of autogenic training as a therapy for adjustment disorder in adolescents. METHOD We observed adjustment disorder indicators and their changes in three phases, using initial, final, and control values, which we measured immediately before the beginning, immediately after the completion, and six months after the completion, of the practical course in autogenic training. We measured systolic and diastolic arterial blood pressure, brachial pulse rates, cortisol levels in plasma, cholesterol levels in blood, as well as glucose concentrations. During that period, autogenic training was employed as the sole therapy. RESULTS The study confirmed our preliminary assumptions. The measurements we performed showed that arterial blood pressure, pulse rates, cholesterol and cortisol concentrations, after the application of autogenic training among adolescents suffering from adjustment disorder, were lower than the initial values. They remained lower even six months after the completion of the practical course in autogenic training. CONCLUSION We concluded that autogenic training significantly decreases the values of physiological indicators of adjustment disorder, diminishes the effects of stress in an individual, and eases the adaptation of

  1. Millijoule pulse energy picosecond fiber chirped-pulse amplification system

    Institute of Scientific and Technical Information of China (English)

    Zhi Yang; Xiaohong Hu; Yishan Wang; Wei Zhang; Wei Zhao

    2011-01-01

    @@ The efficient generation of a 1.17-mJ laser pul8e with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally.A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulse8 with hundreds of picosecond widths.Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier, All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR).The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.%The efficient generation of a 1.17-mJ laser pulse with 360 ps duration using an ytterbium (Yb)-doped fiber amplifier chain seeded by a homemade mode-locked fiber laser is demonstrated experimentally. A specially designed figure-of-eight fiber laser acts as the seed source of a chirped-pulse amplification (CPA) system and generates mode-locked pulses with hundreds of picosecond widths. Two kinds of large-mode-area (LMA) double-clad Yb-doped fibers are employed to construct the pre-amplifier and main amplifier. All of the adopted instruments help avoid severe nonlinearity in fibers to raise sub-nanosecond pulse energy with acceptable signal-to-noise ratio (SNR). The output spectrum of this fiber-based CPA system shows that amplified spontaneous emission (ASE) is suppressed to better than 30 dB, and the onset of stimulated Raman scattering is excluded.

  2. Spinal cord stimulation with interleaved pulses: a randomized, controlled trial.

    Science.gov (United States)

    North, Richard B; Kidd, David H; Olin, John; Sieracki, Jeffrey M; Boulay, Marc

    2007-10-01

    Objectives.  The development of multicontact electrodes and programmable, implanted pulse generators has increased the therapeutic success of spinal cord stimulation (SCS) by enhancing the ability to capture and maintain pain/paresthesia overlap. This study sought to determine if interleaved stimulation and/or frequency doubling improves pain/paresthesia overlap in patients with failed back surgery syndrome. Methods.  Using a patient-interactive computer system that quantifies SCS performance and presents stimulation settings in randomized, double-blind fashion, we compared the effect on pain/paresthesia overlap of interleaved stimulation (rapidly interleaved pulse trains using two different contact combinations) vs. standard treatment with a single contact combination, controlling for frequency doubling. Stimulation amplitude (charge per phase, as determined by varying pulse voltage or width) was adjusted to a subjectively comfortable intensity (usage amplitude), which was maintained for all trials in each patient. The number of percutaneous spinal electrodes used (one or two) and the phase angle between interleaved pulses were additional study variables. Results.  Multivariate analysis of 266 test results from 15 patients revealed a statistically significant (p ≤ 0.05) association between increased computer-calculated pain/paresthesia overlap and 1) high- and low-frequency interleaved stimulation using two combinations of contacts and 2) frequency doubling using one combination. We found no significant effect for electrode configuration (single or dual), pulse width matching, or phase angle. Conclusions.  The statistically significant advantages we observed for SCS with interleaved stimulation are explained, at least in part, by the effects of frequency doubling. These findings have important implications for the design and adjustment of pulse generators. PMID:22150894

  3. Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser

    CERN Document Server

    Liu, Ya; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

    2016-01-01

    Dual-comb lasers from which asynchronous ultrashort pulses can be simultaneously generated have recently become an interesting research subject. They could be an intriguing alternative to the current dual-laser optical-frequency-comb source with highly sophisticated electronic control systems. If generated through a common light path traveled by all pulses, the common-mode noises between the spectral lines of different pulse trains could be significantly reduced. Therefore, coherent dual-comb generation from a completely common-path, unidirectional lasing cavity would be an interesting territory to explore. In this paper, we demonstrate such a dual-comb lasing scheme based on a nanomaterial saturable absorber with additional pulse narrowing and broadening mechanisms concurrently introduced into a mode-locked fiber laser. The interactions between multiple soliton formation mechanisms result in unusual bifurcation into two-pulse states with quite different characteristics. Simultaneous oscillation of pulses wit...

  4. Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser.

    Science.gov (United States)

    Liu, Ya; Zhao, Xin; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

    2016-09-19

    Dual-comb lasers simultaneously generating asynchronous ultrashort pulses could be an intriguing alternative to the current dual-laser comb source. When generated through a common light path, the low common-mode noises and good coherence between the pulse trains could be realized. Here we demonstrate the completely common-path, unidirectional dual-comb lasing using a carbon nanotube saturable absorber with additional pulse narrowing and broadening mechanisms. The interactions between multiple soliton formation mechanisms result in bifurcation into unusual two-pulse states with pulses of four-fold bandwidth difference and tens-of-Hz repetition rate difference. Coherence between the pulses is verified by the asynchronous cross-sampling and dual-comb spectroscopy measurements. PMID:27661880

  5. A nanosecond pulsed accelerator facility

    International Nuclear Information System (INIS)

    The operation and performance of a 3-MeV pulsed electrostatic generator producing 1-ns (10-9 s) pulses is described. The system employs terminal pulsing and post-acceleration time-compression to achieve short pulses and high average current. The specifications for this system were based on the following considerations. A 10-μA average beam current represents a reasonable limit based on the ability of a target to dissipate beam power, the 1-ns pulse-length was consistent with other factors such as detector response, energy homogeneity, etc. which determine over-all time resolution, and a repetition rate of 1 MHz/s gives a duty factor consistent with the current capabilities of existing accelerator ion sources. The system consists of a terminal pulsing component which produces pulses of 10 ns in duration by sweeping a beam over an aperture located at the entrance to an accelerator tube. An average output of a current of 10 μA requires a source capable of producing 1 mA of atomic ions. After acceleration this pulse is compressed to 1 ns by the scheme suggested by Mobley. This involves sweeping the beam with proper synchronization across the aperture of a 90o doubly-focusing deflection magnet so that the early portion of the pulse travels through a longer trajectory thani the later portions, thus achieving time compression when the beam is brought to a focus on a suitable target. The radius of beam curvature in the compression magnet is 30 in and the over-all beam divergence at the target is 5o. The choice of these parameters and the effect of the deflection scheme in the beam-energy homogeneity will be discussed. Using existing nanosecond detector techniques, this system has produced over-all system resolutions of 1 ns full-width at half-maximum for both gamma rays and neutrons. It is not yet known what component or components of the system determine the limits on the time resolution of the system. As a facility for investigating neutron inelastic scattering and

  6. High-energy Picosecond Laser Pulse Recirculation for Compton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, I; Anderson, S G; Betts, S M; Brown, C; Gibson, D J; Hartemann, F V; Hernandez, J E; Johnson, M; McNabb, D P; Messerly, M; Pruet, J; Shverdin, M Y; Siders, C W; Tremaine, A M; Barty, C J

    2007-06-12

    Frequency upconversion of laser-generated photons by inverse Compton scattering for applications such as nuclear spectroscopy and gamma-gamma collider concepts on the future ILC would benefit from an increase of average source brightness. The primary obstacle to higher average brightness is the relatively small Thomson scattering cross section. It has been proposed that this limitation can be partially overcome by use of laser pulse recirculation. The traditional approach to laser recirculation entails resonant coupling of low-energy pulse train to a cavity through a partially reflective mirror. Here we present an alternative, passive approach that is akin to 'burst-mode' operation and does not require interferometric alignment accuracy. Injection of a short and energetic laser pulse is achieved by placing a thin frequency converter, such as a nonlinear optical crystal, into the cavity in the path of the incident laser pulse. This method leads to the increase of x-ray/gamma-ray energy proportional to the increase in photon energy in frequency conversion. Furthermore, frequency tunability can be achieved by utilizing parametric amplifier in place of the frequency converter.

  7. Pulse compression and prepulse suppression apparatus

    Science.gov (United States)

    Dane, C.B.; Hackel, L.A.; George, E.V.; Miller, J.L.; Krupke, W.F.

    1993-11-09

    A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

  8. Experimental research on pulse forming based on high-temperature SMES applied in pulsed power

    Science.gov (United States)

    Zhou, Yusheng; Kuang, Jianghua; Tang, Yuejin; Song, Meng; Wei, Bin; Cheng, Shijie; Pan, Yuan

    2009-03-01

    To research the key problems of storage energy and pulse forming in pulsed power, a pulse magnet made of Bi2223/Ag high-temperature superconducting (HTS) tapes applied in pulsed power experiment was developed. After determining electromagnetic characteristics of the magnet, a pulse forming network was designed. HTS magnet was immersed in liquid nitrogen bath, experiments were carried out about discharging pulse current to resistance load based on HTS magnet energy storage (SMES). The results show that pulse current waves were obtained through adjusted circuit construction and magnet parameters by acting delay of switches in the pulse forming network. The technical schemes about pulse forming based on SMES were presented.

  9. Three-Level 48-Pulse STATCOM with Pulse Width Modulation

    Science.gov (United States)

    Singh, Bhim; Srinivas, Kadagala Venkata

    2016-03-01

    In this paper, a new control strategy of a three-level 48-pulse static synchronous compensator (STATCOM) is proposed with a constant dc link voltage and pulse width modulation at fundamental frequency switching. The proposed STATCOM is realized using eight units of three-level voltage source converters (VSCs) to form a three-level 48-pulse STATCOM. The conduction angle of each three-level VSC is modulated to control the ac converter output voltage, which controls the reactive power of the STATCOM. A fuzzy logic controller is used to control the STATCOM. The dynamic performance of the STATCOM is studied for the control of the reference reactive power, the reference terminal voltage and under the switching of inductive and capacitive loads.

  10. Green pulsed lidar-radar emitter based on a multipass frequency-shifting external cavity.

    Science.gov (United States)

    Zhang, Haiyang; Brunel, Marc; Romanelli, Marco; Vallet, Marc

    2016-04-01

    This paper investigates the radio frequency (RF) up-conversion properties of a frequency-shifting external cavity on a laser beam. We consider an infrared passively Q-switched pulsed laser whose intensity modulation results from the multiple round-trips in the external cavity, which contains a frequency shifter. The output beam undergoes optical second-harmonic generation necessary to reach the green wavelength. We model the pulse train using a rate-equation model to simulate the laser pulses, together with a time-delayed interference calculation taking both the diffraction efficiency and the Gaussian beam propagation into account. The predictions are verified experimentally using a diode-pumped Nd:YAG laser passively Q-switched by Cr4+:YAG whose pulse train makes multiple round-trips in a mode-matched external cavity containing an acousto-optic frequency shifter driven at 85 MHz. Second-harmonic generation is realized in a KTP crystal, yielding RF-modulated pulses at 532 nm with a modulation contrast of almost 100%. RF harmonics up to the 6th order (1.020 GHz) are observed in the green output pulses. Such a RF-modulated green laser may find applications in underwater detection and ranging. PMID:27139644

  11. Key technical issues associated with a method of pulse compression. Final technical report

    International Nuclear Information System (INIS)

    Key technical issues for angular multiplexing as a method of pulse compression in a 100 KJ KrF laser have been studied. Environmental issues studied include seismic vibrations man-made vibrations, air propagation, turbulence, and thermal gradient-induced density fluctuations. These studies have been incorporated in the design of mirror mounts and an alignment system, both of which are reported. A design study and performance analysis of the final amplifier have been undertaken. The pulse compression optical train has been designed and assessed as to its performance. Individual components are described and analytical relationships between the optical component size, surface quality, damage threshold and final focus properties are derived. The optical train primary aberrations are obtained and a method for aberration minimization is presented. Cost algorithms for the mirrors, mounts, and electrical hardware are integrated into a cost model to determine system costs as a function of pulse length, aperture size, and spot size

  12. Second-order fractional Talbot effect induced frequency-doubling optical pulse injection for 40 GHz rational-harmonic mode-locking of an SOA fiber laser

    International Nuclear Information System (INIS)

    A second-order fractional Talbot effect induced frequency-doubling of a 10 GHz optical pulse-train is demonstrated to backward injection mode-lock a semiconductor optical amplifier fiber laser (SOAFL) for 40 GHz rational-harmonic mode-locking (RHML). That is, a real all-optical gain-modulation of the SOAFL can be created by injecting such a time-multiplexed but pseudo-frequency-doubled pulse-train into the cavity. The time-multiplexing pulse-train can thus be transformed into a frequency-multiplied pulse-train via cross-gain modulation (XGM). The optical pulse-train at 10 GHz is generated by nonlinearly driving an electro-absorption modulator (EAM), which experiences the second-order fractional Talbot effect after propagating through a 4 km long dispersion compensation fiber (DCF). The DCF not only plays the role of frequency-doubler but also compensates the frequency chirp of the 10 GHz optical pulse-train. The pulsewidth broadening from 22 to 60 ps for initiating the time-domain Talbot effect is simulated by the nonlinear Schrödinger equation. With careful detuning of the RF modulation power of the EAM at 5 dBm, the generated 20 GHz optical pulse-train exhibits a positive frequency chirp with minimum peak-to-peak value of 2 GHz, and the peak-amplitude fluctuation between adjacent pulses is below 1.4%. In comparison with the SOAFL pulse-train repeated at 40 GHz generated by the fourth-order purely RHML process, the optimized second-order fractional Talbot effect in combination with the second-order RHML mechanism significantly enhances the modulation-depth of RHML, thus improving the on/off extinction ratio of the 40 GHz SOAFL pulse-train from 1.8 to 5.6 dB. Such a new scheme also provides a more stable 40 GHz RHML pulse-train from the SOAFL with its timing jitter reducing from 0.51 to 0.23 ps. (paper)

  13. Wide Range SET Pulse Measurement

    Science.gov (United States)

    Shuler, Robert L.; Chen, Li

    2012-01-01

    A method for measuring a wide range of SET pulses is demonstrated. Use of dynamic logic, faster than ordinary CMOS, allows capture of short pulses. A weighted binning of SET lengths allows measurement of a wide range of pulse lengths with compact circuitry. A pulse-length-conservative pulse combiner tree routes SETs from combinational logic to the measurement circuit, allowing SET measurements in circuits that cannot easily be arranged in long chains. The method is applied to add-multiplex combinational logic, and to an array of NFET routing switches, at .35 micron. Pulses are captured in a chain of Domino Logic AND gates. Propagation through the chain is frozen on the trailing edge by dropping low the second "enable" input to the AND gates. Capacitive loading is increased in the latter stages to create an approximately logarithmic weighted binning, so that a broad range of pulse lengths can be captured with a 10 stage capture chain. Simulations show pulses can be captured which are 1/5th the length of those typically captured with leading edge triggered latch methods, and less than the length of those captured with a trailing edge latch method. After capture, the pulse pattern is transferred to an SEU protected shift register for readout. 64 instances of each of two types of logic are used as targets. One is a full adder with a 4 to 1 mux on its inputs. The other is a 4 x 4 NFET routing matrix. The outputs are passed through buffered XNOR comparators to identify pulses, which are merged in a buffered not-nand (OR) tree designed to avoid pulse absorption as much as possible. The output from each of the two test circuits are input into separate pulse measurement circuits. Test inputs were provided so that the circuit could be bench tested and calibrated. A third SET measurement circuit with no inputs was used to judge the contribution from direct hits on the measurement circuit. Heavy ions were used with an LET range from 12 to 176. At LET of 21 and below, the very

  14. Pulse Detonation Engine Test Bed Developed

    Science.gov (United States)

    Breisacher, Kevin J.

    2002-01-01

    A detonation is a supersonic combustion wave. A Pulse Detonation Engine (PDE) repetitively creates a series of detonation waves to take advantage of rapid burning and high peak pressures to efficiently produce thrust. NASA Glenn Research Center's Combustion Branch has developed a PDE test bed that can reproduce the operating conditions that might be encountered in an actual engine. It allows the rapid and cost-efficient evaluation of the technical issues and technologies associated with these engines. The test bed is modular in design. It consists of various length sections of both 2- and 2.6- in. internal-diameter combustor tubes. These tubes can be bolted together to create a variety of combustor configurations. A series of bosses allow instrumentation to be inserted on the tubes. Dynamic pressure sensors and heat flux gauges have been used to characterize the performance of the test bed. The PDE test bed is designed to utilize an existing calorimeter (for heat load measurement) and windowed (for optical access) combustor sections. It uses hydrogen as the fuel, and oxygen and nitrogen are mixed to simulate air. An electronic controller is used to open the hydrogen and air valves (or a continuous flow of air is used) and to fire the spark at the appropriate times. Scheduled tests on the test bed include an evaluation of the pumping ability of the train of detonation waves for use in an ejector and an evaluation of the pollutants formed in a PDE combustor. Glenn's Combustion Branch uses the National Combustor Code (NCC) to perform numerical analyses of PDE's as well as to evaluate alternative detonative combustion devices. Pulse Detonation Engine testbed.

  15. The pulsing CPSD method for subcritical assemblies with pulsed sources

    CERN Document Server

    Ballester, D; Ballester, Daniel; Munoz-Cobo, Jose L.

    2005-01-01

    Stochastic neutron transport theory is applied to the derivation of the two-neutron-detectors cross power spectral density for subcritical assemblies when external pulsed sources are used. A general relationship between the two-detector probability generating functions of the kernel and the source is obtained considering the contribution to detectors statistics of both the pulsed source and the intrinsic neutron source. An expansion in alpha-eigenvalues is derived for the final solution, which permits to take into account the effect of higher harmonics in subcritical systems. Further, expressions corresponding to the fundamental mode approximation are compared with recent results from experiments performed under the MUSE-4 European research project.

  16. Pre-earthquake magnetic pulses

    Directory of Open Access Journals (Sweden)

    J. Scoville

    2014-12-01

    Full Text Available A semiconductor model of rocks is shown to describe unipolar magnetic pulses, a phenomenon that has been observed prior to earthquakes. These pulses are generated deep in the Earth's crust, in and around the Hypocentral volume, days or even weeks before Earthquakes. They are observable at the surface because their extremely long wavelength allows them to pass through kilometers of rock. Interestingly, the source of these pulses may be triangulated to pinpoint locations where stresses are building deep within the crust. We couple a semiconductor drift-diffusion model to a magnetic field in order to describe the electromagnetic effects associated with electrical currents flowing within rocks. The resulting system of equations is solved numerically and it is seen that a volume of rock may act as a diode that produces transient currents when it switches bias. These unidirectional currents are expected to produce transient unipolar magnetic pulses similar in form, amplitude, and duration to those observed before earthquakes, and this suggests that the pulses could be the result of geophysical semiconductor processes.

  17. Effects of cochlear-implant pulse rate and inter-channel timing on channel interactions and thresholds

    Science.gov (United States)

    Middlebrooks, John C.

    2004-07-01

    Interactions among the multiple channels of a cochlear prosthesis limit the number of channels of information that can be transmitted to the brain. This study explored the influence on channel interactions of electrical pulse rates and temporal offsets between channels. Anesthetized guinea pigs were implanted with 2-channel scala-tympani electrode arrays, and spike activity was recorded from the auditory cortex. Channel interactions were quantified as the reduction of the threshold for pulse-train stimulation of the apical channel by sub-threshold stimulation of the basal channel. Pulse rates were 254 or 4069 pulses per second (pps) per channel. Maximum threshold reductions averaged 9.6 dB when channels were stimulated simultaneously. Among nonsimultaneous conditions, threshold reductions at the 254-pps rate were entirely eliminated by a 1966-μs inter-channel offset. When offsets were only 41 to 123 μs, however, maximum threshold shifts averaged 3.1 dB, which was comparable to the dynamic ranges of cortical neurons in this experimental preparation. Threshold reductions at 4069 pps averaged up to 1.3 dB greater than at 254 pps, which raises some concern in regard to high-pulse-rate speech processors. Thresholds for various paired-pulse stimuli, pulse rates, and pulse-train durations were measured to test possible mechanisms of temporal integration.

  18. Determination of Anaerobic Threshold by Monitoring the O2 Pulse Changes in Endurance Cyclists.

    Science.gov (United States)

    Nikooie, Rohollah

    2016-06-01

    Nikooie, R. Determination of anaerobic threshold by monitoring the O2 pulse changes in endurance cyclists. J Strength Cond Res 30(6): 1700-1707, 2016-The purpose of this study was to determine the validity of anaerobic threshold (AnT)-equivalent to the second turn point for lactate (LTP2)-estimation using the O2 pulse changes in highly trained endurance cyclists who do not show heart rate deflection point (HRDP) during incremental testing. Sixteen endurance cyclists (age, 24.8 ± 4.7 years) and fifteen active men (age, 24.8 ± 3.7 years) performed an incremental cycling test to exhaustion. Pulmonary oxygen uptake (V[Combining Dot Above]O2) and other hemodynamic variables, heart rate, and blood lactate concentration were measured continuously throughout the test. O2 pulse anaerobic threshold (O2 pulse-AnT) was defined as the second turn point in O2 pulse-workload curve. LTP2 was considered as gold standard assessment of AnT and was applied to confirm the validity of O2 pulse-AnT. Intraclass correlation coefficients and the Bland-Altman method were used to determine the relationship and agreement between the O2 corresponding to LTP2 and O2 pulse-AnT, respectively. The active men and 68.7% of the endurance cyclists showed HRDP, whereas all subjects showed O2 pulse-AnT during incremental testing. In both groups, the values for V[Combining Dot Above]O2 corresponding to LTP2 were not significantly different from the V[Combining Dot Above]O2 at O2 pulse-AnT. The V[Combining Dot Above]O2 at LTP2 and O2 pulse-AnT were highly correlated (endurance cyclists: R = 0.68; standard error of estimate [SEE] = 3.74 ml·kg·min and active men: R = 0.58; SEE = 2.91 ml·kg·min) and Bland-Altman plot revealed the limit of agreement of O2 at LTP2 and O2 pulse-AnT differences between 5.1 and 8.6 ml·kg·min (95% CI). In summary, results of this study showed that the second turn point in the O2 pulse-workload curve occurs around LTP2. Therefore, using O2 pulse-AnT is recommended for the

  19. Characteristics of Preliminary Breakdown Pulses in Positive Ground Flashes during Summer Thunderstorms in Sweden

    Directory of Open Access Journals (Sweden)

    Dalina Johari

    2016-03-01

    Full Text Available This paper presents the characteristics of the preliminary breakdown pulses (PBP in 51 positive ground flashes recorded during 2014 summer thunderstorms in Sweden. Electric field measurements were conducted remotely using a broadband antenna system (up to 100 MHz for a recording length of 1 s with 200 ms trigger time. In the analysis, PBP trains were observed in 86% of the cases. Based on the number of trains preceding the first return stroke, the PBP were classified into single and multiple train PBP. Characteristics of the first PBP train were determined and based on the initial polarity of the pulses, three types of PBP were identified. Characteristics of the subsequent PBP trains in the multiple train PBP were also analyzed and they were compared with the first PBP train. Based on the conceptual charge cloud configuration, we found that the inverted dipole is consistent with our observation. We also found that PBP in positive ground flashes during summer thunderstorms in Sweden are weak since the average ratios of the PBP peak to the first return stroke peak lie only between 0.21 and 0.26. Possible reasons for no detection of PBP and the different types of PBP observed were also discussed.

  20. Biofeedback Training as Counseling

    Science.gov (United States)

    Danskin, David G.; Walters, E. Dale

    1975-01-01

    Encourages professionals in helping relationships to explore and experience biofeedback training for voluntary self-regulation. A sample biofeedback training program is described. Observations of participants in biofeedback programs are presented. (Author/BW)

  1. Technical training: places available

    CERN Multimedia

    2014-01-01

    If you would like more information on a course, or have any other inquiry/suggestions, please contact Technical.Training@cern.ch. Eva Stern and Elise Romero, Technical Training Administration (Tel: 74924)

  2. Technical training: places available

    CERN Multimedia

    2014-01-01

    If you would like more information on a course, or have any other inquiry/suggestions, please contact Technical.Training@cern.ch. Eva Stern and Marie Lahchimi, Technical Training Administration (Tel: 74924)

  3. Technical training: places available

    CERN Multimedia

    2013-01-01

    If you would like more information on a course, or for any other inquiry/suggestions, please contact Technical.Training@cern.ch. Eva Stern and Elise Romero, Technical Training Administration (Tel: 74924)

  4. Technical training: places available

    CERN Multimedia

    2013-01-01

    If you would like more information on a course, or for any other inquiry/suggestions, please contact Technical.Training@cern.ch. Eva Stern and Elise Romero, Technical Training Administration (Tél : 74924)  

  5. Technical training - places available

    CERN Multimedia

    2013-01-01

    If you would like more information on a course, or have any other inquiry/suggestions, please contact Technical.Training@cern.ch. Eva Stern and Elise Romero, Technical Training Administration (Tel: 74924)

  6. Pulsed liquid microjet for microsurgery

    Science.gov (United States)

    Fletcher, D. A.; Palanker, D. V.

    2001-03-01

    The precision of soft tissue dissection with pulsed lasers in liquid media is typically limited by collateral damage from vapor bubbles created during energy deposition. We present an alternative technique for creating incisions using a pulsed liquid microjet driven by an electric discharge-induced vapor bubble generated inside a micronozzle. We use this technique to create a pulsed jet 30 μm in diameter with a peak velocity of 90 m/s and total ejected volume on the order of 100 pl. Incision tests on a polyacrylamide gel simulating soft tissue show that the width of the cut is comparable to the diameter of the micronozzle and that collateral damage is significantly less than that produced by a vapor bubble not confined by the nozzle.

  7. Radial flow pulse jet mixer

    Science.gov (United States)

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  8. Pulsed neutron sources at Dubna

    International Nuclear Information System (INIS)

    In 1960 the first world repetitively pulsed reactor IBR was put into operation. It was the beginning of the story how fission based pulsed neutron sources at Dubna have survived. The engineers involved have experienced many successes and failures in the course of new sources upgrading to finally come to possess the world's brightest neutron source - IBR-2. The details are being reviewed through the paper. The fission based pulsed neutron sources did not reach their final state as yet- the conceptual views of IBR prospects are being discussed with the goal to double the thermal neutron peak flux (up to 2x1016) and to enhance the cold neutron flux by 10 times (with the present one being as high that of the ISIS cold moderator). (author)

  9. Pulsed discharge production Ar* metastables

    Science.gov (United States)

    Han, Jiande; Heaven, Michael C.; Emmons, Daniel; Perram, Glen P.; Weeks, David E.; Bailey, William F.

    2016-03-01

    The production of relatively high densities of Ar* metastables (>1012 cm-3) in Ar/He mixtures, at total pressures close to 1 atm, is essential for the efficient operation of an optically pumped Ar* laser. We have used emission spectroscopy and diode laser absorption spectroscopy measurements to observe the production and decay of Ar* in a parallel plate pulsed discharge. With discharge pulses of 1 μs duration we find that metastable production is dominated by processes occurring within the first 100 ns of the gas break-down. Application of multiple, closely spaced discharge pulses yields insights concerning conditions that favor metastable production. This information has been combined with time-resolved measurements of voltage and current. The experimental results and preliminary modeling of the discharge kinetics are presented.

  10. Thermal lensing effect of CS2 studied with femtosecond laser pulses.

    Science.gov (United States)

    Li, Yi-Ci; Kuo, Yu-Ting; Huang, Po-Yuan; Yang, Sidney S; Lee, Cheng-I; Wei, Tai-Huei

    2015-10-14

    By chopping 820 nm 18 femtosecond (fs)-laser pulses, continuously generated by a self-mode locked Ti:Al2O3 laser at 82 MHz, into trains with both train-width and train-to-train separation considerably longer than the thermal diffusivity time constant τth of CS2, we conducted Z-scan measurements on it at various times relative to the leading pulse of each train (T's). As a result, we observed negative nonlinear refraction strengthening with T within τth and gradually stabilizing with T exceeding τth. We quantitatively explain the experimental results in terms of the thermal lensing effect. In particular, we attribute the heat generation to non-radiative relaxation of libration excited by individual 18 fs-pulses via stimulated Raman scattering. In contrast to the commonly held view of multi-photon excitation, we propose and verify a new heat-generating mechanism for the thermal lensing effect in CS2. PMID:26246122

  11. Pulsed gate bias control of GaN HEMTs to improve pulse-to-pulse stability in radar applications

    OpenAIRE

    Delprato, Julien; Delias, Arnaud; Medrel, Pierre; Barataud, Denis; Campovecchio, Michel; Neveux, Guillaume; Martin, Audrey; Bouysse, Philippe; Nebus, Jean-Michel; Tolant, C.; Eudeline, P.

    2015-01-01

    A significant improvement is demonstrated in the measured pulse-to-pulse stability of an S-band 6 W GaN high electron mobility transistor (HEMT) power amplifier by generating an appropriate pulse of the gate bias and thus a warm-up drain current just before each radio-frequency (RF) pulse of a periodic and coherent radar burst. The amplitude and the width of this gate bias pulse preceding each periodic RF pulse of the burst are experimentally varied to investigate the trade-off between the im...

  12. Human factors in training

    International Nuclear Information System (INIS)

    The Human Factors concept is a focused effort directed at those activities which require human involvement. Training is, by its nature, an activity totally dependent on the Human Factor. This paper identifies several concerns significant to training situations and discusses how Human Factor awareness can increase the quality of learning. Psychology in the training arena is applied Human Factors. Training is a method of communication represented by sender, medium, and receiver. Two-thirds of this communications model involves the human element directly

  13. Training Recurrent Networks

    DEFF Research Database (Denmark)

    Pedersen, Morten With

    1997-01-01

    Training recurrent networks is generally believed to be a difficult task. Excessive training times and lack of convergence to an acceptable solution are frequently reported. In this paper we seek to explain the reason for this from a numerical point of view and show how to avoid problems when...... training. In particular we investigate ill-conditioning, the need for and effect of regularization and illustrate the superiority of second-order methods for training...

  14. Kalman Filter Neuron Training

    OpenAIRE

    Murase, Haruhiko; KOYAMA, Shuhei; HONAMI, Nobuo; Kuwabara, Takao

    1991-01-01

    An attempt of implementing Kalman filter algorithm in the procedure for training the neural network was made and evaluated. The Kalman filter neuron training program (KNT) was coded. The performance of Kalman filter in KNT was compared to commonly used neuron training algorithm. The study revealed that KNT requires much less calculation time to accomplish neuron training than commonly used other algorithms do. KNT also gave much smaller final error than any other algorithms tested in this study.

  15. Criticality safety training

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, S.K. [Los Alamos National Lab., NM (United States)

    1997-06-01

    Criticality safety training is an important element of the Plutonium Facility safety program at Los Alamos National Laboratory. Training consists of student self-study handbooks and hands-on performance-based training in a mock-up laboratory containing gloveboxes, trolley conveyor system, and self-monitoring instruments. A 10-minute video tape and lecture was presented to describe how training in this area is conducted.

  16. Experimental Study of a Pulsed Ytterbium-Doped Fibre Laser with Fast and Slow Saturable Absorbers in a Linear Cavity

    Institute of Scientific and Technical Information of China (English)

    GAN Yu; XIANG Wang-Hua; ZHOU Xiao-Fang; ZHANG Gui-Zhong; ZHANG Bing; WANG Yong-Gang; MA Xiao-Yu

    2006-01-01

    @@ We present a linear-cavity stretched-pulse fibre laser with mode locking by a nonlinear polarization rotation and by semiconductor saturable-absorber mirrors. A Q-switched mode-locking cw train and a mode-locking pulse train are obtained in the experiment. We investigate the effects of the equivalent fast saturable absorber and the slow saturable absorbers in experiment. It is found that neither the nonlinear polarization evolution effect nor a semiconductor saturable absorber mirror is enough to produce the stable cw mode-locking pulses in this experiment. A nonlinear polarization evolution effect controls the cavity loss to literally carve the pulses;semiconductor saturable absorber mirrors provide the self-restarting and maintain the stability of the modelocking operation.

  17. Pulse compressor with aberration correction

    Energy Technology Data Exchange (ETDEWEB)

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States)

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  18. Pulsed neutron porosity logging system

    International Nuclear Information System (INIS)

    An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations and, during the bursts, the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

  19. High-speed pulse techniques

    CERN Document Server

    Coekin, J A

    1975-01-01

    High-Speed Pulse Techniques covers the many aspects of technique in digital electronics and encompass some of the more fundamental factors that apply to all digital systems. The book describes the nature of pulse signals and their deliberate or inadvertent processing in networks, transmission lines and transformers, and then examines the characteristics and transient performance of semiconductor devices and integrated circuits. Some of the problems associated with the assembly of these into viable systems operating at ultra high speed are also looked at. The book examines the transients and w

  20. Short optical pulse generation at 40 GHz with a bulk electro-absorption modulator packaged device

    Science.gov (United States)

    Langlois, Patrick; Moore, Ronald; Prosyk, Kelvin; O'Keefe, Sean; Oosterom, Jill A.; Betty, Ian; Foster, Robert; Greenspan, Jonathan; Singh, Priti

    2003-12-01

    Short optical pulse generation at 40GHz and 1540nm wavelength is achieved using fully packaged bulk quaternary electro-absorption modulator modules. Experimental results obtained with broadband and narrowband optimized packaged modules are presented and compared against empirical model predictions. Pulse duty cycle, extinction ratio and chirp are studied as a function of sinusoidal drive voltage and detuning between operating wavelength and modulator absorption band edge. Design rules and performance trade-offs are discussed. Low-chirp pulses with a FWHM of ~12ps and sub-4ps at a rate of 40GHz are demonstrated. Optical time-domain demultiplexing of a 40GHz to a 10GHz pulse train is also demonstrated with better than 20dB extinction ratio.

  1. Femtosecond laser microchannels fabrication based on electrons dynamics control using temporally or spatially shaped pulses

    Science.gov (United States)

    Yan, Xueliang; Hu, Jie; Li, Xiaowei; Xia, Bo; Liu, Pengjun; Lu, Yongfeng; Jiang, Lan

    2014-11-01

    With ultrashort pulse durations and ultrahigh power densities, femtosecond laser presents unique advantages of high precision and high quality fabrication of microchannels in transparent materials. In our study, by shaping femtosecond laser pulse energy distribution in temporal or spatial domains, localized transient electrons dynamics and the subsequent processes, such as phase changes, can be controlled, leading to the dramatic increases in the capability of femtosecond laser microchannels fabrication. The temporally shaped femtosecond laser pulse trains can significantly enhance the material removal rate in both water-assisted femtosecond laser drilling and femtosecond laser irradiation followed by chemical etching. Besides, high-aspect-ratio and small-diameter microchannels are drilled by spatially shaped femtosecond laser pulses.

  2. Neuromuscular disruption with ultrashort electrical pulses

    Science.gov (United States)

    Pakhomov, Andrei; Kolb, Juergen F.; Joshi, Ravindra P.; Schoenbach, Karl H.; Dayton, Thomas; Comeaux, James; Ashmore, John; Beason, Charles

    2006-05-01

    Experimental studies on single cells have shown that application of pulsed voltages, with submicrosecond pulse duration and an electric field on the order of 10 kV/cm, causes sudden alterations in the intracellular free calcium concentration, followed by immobilization of the cell. In order to examine electrical stimulation and incapacitation with such ultrashort pulses, experiments on anesthetized rats have been performed. The effect of single, 450 nanosecond monopolar pulses have been compared with that of single pulses with multi-microsecond duration (TASER pulses). Two conditions were explored: 1. the ability to elicit a muscle twitch, and, 2. the ability to suppress voluntary movement by using nanosecond pulses. The second condition is relevant for neuromuscular incapacitation. The preliminary results indicate that for stimulation microsecond pulses are advantageous over nanosecond pulses, whereas for incapacitation, the opposite seems to apply. The stimulation effects seem to scale with electrical charge, whereas the disruption effects don't follow a simple scaling law. The increase in intensity (time of incapacitation) for a given pulse duration, is increasing with electrical energy, but is more efficient for nanosecond than for microsecond pulses. This indicates different cellular mechanisms for incapacitation, most likely subcellular processes, which have been shown to become increasingly important when the pulse duration is shortened into the nanosecond range. If further studies can confirm these initial results, consequences of reduced pulse duration are a reduction in weight and volume of the pulse delivery system, and likely, because of the lower required energy for neuromuscular incapacitation, reduced safety risks.

  3. Training and Learning

    Science.gov (United States)

    Luntley, Michael

    2008-01-01

    Some philosophers of education think that there is a pedagogically informative concept of training that can be gleaned from Wittgenstein's later writings: training as initiation into a form of life. Stickney, in "Training and Mastery of Techniques in Wittgenstein's Later Philosophy: A response to Michael Luntley" takes me to task for ignoring this…

  4. Human Factors in Training

    Science.gov (United States)

    Barshi, Immanuel; Byrne, Vicky; Arsintescu, Lucia; Connell, Erin

    2010-01-01

    Future space missions will be significantly longer than current shuttle missions and new systems will be more complex than current systems. Increasing communication delays between crews and Earth-based support means that astronauts need to be prepared to handle the unexpected on their own. As crews become more autonomous, their potential span of control and required expertise must grow to match their autonomy. It is not possible to train for every eventuality ahead of time on the ground, or to maintain trained skills across long intervals of disuse. To adequately prepare NASA personnel for these challenges, new training approaches, methodologies, and tools are required. This research project aims at developing these training capabilities. By researching established training principles, examining future needs, and by using current practices in space flight training as test beds, both in Flight Controller and Crew Medical domains, this research project is mitigating program risks and generating templates and requirements to meet future training needs. Training efforts in Fiscal Year 09 (FY09) strongly focused on crew medical training, but also began exploring how Space Flight Resource Management training for Mission Operations Directorate (MOD) Flight Controllers could be integrated with systems training for optimal Mission Control Center (MCC) operations. The Training Task addresses Program risks that lie at the intersection of the following three risks identified by the Project: 1) Risk associated with poor task design; 2) Risk of error due to inadequate information; and 3) Risk associated with reduced safety and efficiency due to poor human factors design.

  5. Foundry Industry Training Committee

    Science.gov (United States)

    Industrial Training Journal, 1974

    1974-01-01

    The Foundry Industry Training Committee has encouraged the foundry industry in developing systematic manpower training and development programs at all levels. Features developed include competitions as a technique of standard setting, recommendations for technician training, and a widely used manpower information system. (MW)

  6. Time Use on Trains

    DEFF Research Database (Denmark)

    Bjørner, Thomas

    2016-01-01

    This study explores how travel time is used and how passengers conceptualise travel time in Danish intercity trains and intercity fast trains. The new contribution to the literature this study can offer is in the inclusion of all kinds of passengers in the different compartments to understand train...

  7. 105 W ultra-narrowband nanosecond pulsed laser at 2 μm based on monolithic Tm-doped fiber MOPA.

    Science.gov (United States)

    Wang, Xiong; Jin, Xiaoxi; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2015-02-23

    We present a high power ultra-narrowband pulsed fiber amplifier at 2 μm. A single frequency fiber laser was modulated by a phase modulator and an intensity modulator to serve as the ultra-narrowband pulsed seed laser with a bandwidth of 307 MHz. The pulsed seed laser was amplified by a monolithic Tm-doped fiber master oscillator power amplifier (MOPA). The average output power reaches 105 W with a slope efficiency of 0.41. The output pulse train has a repetition rate of 1 MHz and a pulse width of 66 ns. The output power is limited by the onset of stimulated Brillouin scattering. Higher output power can be achieved by further broadening the linewidth or narrowing the pulse width to several nanoseconds. To the best of our knowledge, this is the first demonstration on a monolithic ultra-narrowband nanosecond pulsed MOPA at 2 μm with an average power exceeding 100 W. PMID:25836461

  8. Dynamic Characterization of Fiber Optical Chirped Pulse Amplification for Sub-ps Pulses

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Rishøj, Lars Søgaard;

    2013-01-01

    We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation.......We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation....

  9. Stimulated Raman scattering effect on femtosecond pulse generation using a parabolic amplification and a pulse compressor

    OpenAIRE

    Soh, Daniel B.S.; Grudinin, A.B.; Nilsson, J.; Y. Jeong; Yoo, S.; Kim, J.; Codemard, C.; Dupriez, P.

    2005-01-01

    An explicit analytical form for the Stokes pulse evolution in parabolic amplification is derived for the first time. In order to achieve efficient pulse compression, the parabolic amplifiers should be operated in the small Stokes pulse regime where the signal pulse is not seriously deteriorated. An analytical expression to obtain the critical fibre length for small Stokes pulse regime is also derived. The pulse compression of the output signal at various fiber lengths also confirms that ...

  10. Knowledge of pulse oximetry among medical and nursing staff

    Directory of Open Access Journals (Sweden)

    Dimitrios Kosmidis

    2007-04-01

    Full Text Available The pulse oximetry is a widely used non invasive method for monitoring the arterial oxygenation. The doctors and the nurses are persons which are in charge for right interpretation of measurements, receiving suitable interventions for the management of patients. Aim: To assess nurses' and doctors' knowledge of pulse oximetry and identify training needs. Material and method: Participants in this study were 376 doctors and nurses from critical and general care settings in seven hospitals in Greece. The data collection was done through a self-administered questionnaire. Frequency of use, critical care experience, and opinions about education needs were included in demographic data. The knowledge test consisted of a 15 item, multiple-choice questionnaire, designed by researchers based on international bibliography. Results: A 70,7% of participants, use pulse oximeter often and 66,3% consider that is very useful in daily clinical practice. 83,7% didn't have some type of past education while more than 81,4% believes that they need further education. The average score for all (on a 15-point scale was 8,5. Ιn particular, the average score for each team had as follows: 10,5±2,7 for the specialized doctors, 9,6±3,1 for residents, 7,8±3,3 for the nurses and 7,4±3,4 for the nurse assistants. Low percentages of right answers were observed mainly in the questions about principles on which the pulse oximetry are based, clinical application and limitations, as well as normal ranges. Conclusion: The comprehension of pulse oximetry is insufficient, mainly in the nursing staff while totally is observed the need for further education.

  11. Ultrafast Relaxation Dynamics of Highly-excited States in N2 Molecules Excited by Femtosecond XUV Pulses

    Directory of Open Access Journals (Sweden)

    Vrakking Marc J.J.

    2013-03-01

    Full Text Available We used velocity-map-imaging to measure electronic and nuclear dynamics in N2 molecules excited by a train of attosecond pulses. A time-to-space mapping of autoionization channel is demonstrated. It is found that the autoionization becomes energetically allowed when the two nuclei are still very close (~ 3 Å and that it can be coherently manipulated by a strong femtosecond infrared pulse.

  12. Radiological worker training

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-10-01

    This Handbook describes an implementation process for core training as recommended in Implementation Guide G441.12, Radiation Safety Training, and as outlined in the DOE Radiological Control Standard (RCS). The Handbook is meant to assist those individuals within the Department of Energy, Managing and Operating contractors, and Managing and Integrating contractors identified as having responsibility for implementing core training recommended by the RCS. This training is intended for radiological workers to assist in meeting their job-specific training requirements of 10 CFR 835. While this Handbook addresses many requirements of 10 CFR 835 Subpart J, it must be supplemented with facility-specific information to achieve full compliance.

  13. Effective mechanic training

    International Nuclear Information System (INIS)

    The need for the training of mechanics is discussed, and the increased interest within the utility industry of placing a similar importance on this training as it has traditionally placed on operator training, is expressed. Effective approaches and techniques are described. Fundamental mechanical maintenance concepts and their practical application are discussed, including the use of supporting video programs. The importance of follow-up practical shop exercise which reinforces classroom instruction is stressed, drawing from practical utility experience. Utilizing success in training as a measure of eligibility for advancement is discussed as well as the interface between training and the company bargaining unit

  14. Training techniques for industry

    International Nuclear Information System (INIS)

    The advantages and disadvantages of commonly used training techniques in relation to cost-effective, prevention-oriented Quality Assurance are examined. Important questions are whether training techniques teach cost effectiveness and whether the techniques are, themselves, cost effective. To answer these questions, criteria for evaluating teaching techniques for cost effectiveness were developd, and then commonly used techniques are evaluated in terms of specific training program objectives. Motivation of personnel is also considered important to the success of a training program, and methods are outlined by which recognition of the academic quality of industrial training can be used as a motivational technique

  15. Radiological worker training

    International Nuclear Information System (INIS)

    This Handbook describes an implementation process for core training as recommended in Implementation Guide G441.12, Radiation Safety Training, and as outlined in the DOE Radiological Control Standard (RCS). The Handbook is meant to assist those individuals within the Department of Energy, Managing and Operating contractors, and Managing and Integrating contractors identified as having responsibility for implementing core training recommended by the RCS. This training is intended for radiological workers to assist in meeting their job-specific training requirements of 10 CFR 835. While this Handbook addresses many requirements of 10 CFR 835 Subpart J, it must be supplemented with facility-specific information to achieve full compliance

  16. Formation of plasma channels in air under filamentation of focused ultrashort laser pulses

    Science.gov (United States)

    Ionin, A. A.; Seleznev, L. V.; Sunchugasheva, E. S.

    2015-03-01

    The formation of plasma channels in air under filamentation of focused ultrashort laser pulses was experimentally and theoretically studied together with theoreticians of the Moscow State University and the Institute of Atmospheric Optics. The influence of various characteristics of ultrashort laser pulses on these plasma channels is discussed. Plasma channels formed under filamentation of focused laser beams with a wavefront distorted by spherical aberration (introduced by adaptive optics) and by astigmatism, with cross-section spatially formed by various diaphragms and with different UV and IR wavelengths, were experimentally and numerically studied. The influence of plasma channels created by a filament of a focused UV or IR femtosecond laser pulse (λ = 248 nm or 740 nm) on characteristics of other plasma channels formed by a femtosecond pulse at the same wavelength following the first one with varied nanosecond time delay was also experimentally studied. An application of plasma channels formed due to the filamentation of focused UV ultrashort laser pulses including a train of such pulses and a combination of ultrashort and long (~100 ns) laser pulses for triggering and guiding long (~1 m) electric discharges is discussed.

  17. Wave equations for pulse propagation

    Science.gov (United States)

    Shore, B. W.

    1987-06-01

    Theoretical discussions of the propagation of pulses of laser radiation through atomic or molecular vapor rely on a number of traditional approximations for idealizing the radiation and the molecules, and for quantifying their mutual interaction by various equations of propagation (for the radiation) and excitation (for the molecules). In treating short-pulse phenomena it is essential to consider coherent excitation phenomena of the sort that is manifest in Rabi oscillations of atomic or molecular populations. Such processes are not adequately treated by rate equations for excitation nor by rate equations for radiation. As part of a more comprehensive treatment of the coupled equations that describe propagation of short pulses, this memo presents background discussion of the equations that describe the field. This memo discusses the origin, in Maxwell's equations, of the wave equation used in the description of pulse propagation. It notes the separation into lamellar and solenoidal (or longitudinal and transverse) and positive and negative frequency parts. It mentions the possibility of separating the polarization field into linear and nonlinear parts, in order to define a susceptibility or index of refraction and, from these, a phase and group velocity.

  18. Pulsed neutron generator for logging

    International Nuclear Information System (INIS)

    A pulsed neutron generator for uranium logging is described. This generator is one component of a prototype uranium logging probe which is being developed by SLA to detect, and assay, uranium by borehole logging. The logging method is based on the measurement of epithermal neutrons resulting from the prompt fissioning of uranium from a pulsed source of 17.6 MeV neutrons. An objective of the prototype probe was that its diameter not exceed 2.75 inches, which would allow its use in conventional rotary drill holes of 4.75-inch diameter. This restriction limited the generator to a maximum 2.375-inch diameter. The performance requirements for the neutron generator specified that it operate with a nominal output of 5 x 106 neutrons/pulse at up to 100 pulses/second for a one-hour period. The development of a neutron generator meeting the preliminary design goals was completed and two prototype models were delivered to SLA. These two generators have been used by SLA to log a number of boreholes in field evaluation of the probe. The results of the field evaluations have led to the recommendation of several changes to improve the probe's operation. Some of these changes will require additional development effort on the neutron generator. It is expected that this work will be performed during 1977. The design and operation of the first prototype neutron generators is described

  19. Ptychographic reconstruction of attosecond pulses

    CERN Document Server

    Lucchini, M; Ludwig, A; Gallmann, L; Keller, U; Feurer, T

    2015-01-01

    We demonstrate a new attosecond pulse reconstruction modality which uses an algorithm that is derived from ptychography. In contrast to other methods, energy and delay sampling are not correlated, and as a result, the number of electron spectra to record is considerably smaller. Together with the robust algorithm, this leads to a more precise and fast convergence of the reconstruction.

  20. Ultrashort-pulse laser machining

    Energy Technology Data Exchange (ETDEWEB)

    Banks, P S; Feit, M D; Nguyen, H T; Perry, M D; Rubenchik, A M; Sefcik, J A; Stuart, B C

    1998-09-01

    A new type of material processing is enabled with ultrashort (t < 10 ps) laser pulses. Cutting, drilling, sculpting of all materials (biologic materials, ceramics, sapphire, silicon carbide, diamond, metals) occurs by new mechanisms that eliminate thermal shock or collateral damage. High-precision machining to submicron tolerances is enabled resulting in high surface quality and negligible heat affected zone.

  1. Ultrashort-pulse lasers machining

    Energy Technology Data Exchange (ETDEWEB)

    Banks, P S; Feit, M D; Nguyen, H T; Perry, M D, Stuart, B C

    1999-01-22

    A new type of material processing is enabled with ultrashort (t < 10 psec) laser pulses. Cutting, drilling, sculpting of all materials (biologic materials, ceramics, sapphire, silicon carbide, diamond, metals) occurs by new mechanisms which eliminate thermal shock or collateral damage. High precision machining to submicron tolerances is enabled resulting in high surface quality and negligible heat affected zone.

  2. Nonparametric estimation of ultrasound pulses

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Leeman, Sidney

    1994-01-01

    An algorithm for nonparametric estimation of 1D ultrasound pulses in echo sequences from human tissues is derived. The technique is a variation of the homomorphic filtering technique using the real cepstrum, and the underlying basis of the method is explained. The algorithm exploits a priori...

  3. Academic Training: Academic Training Lectures-Questionnaire

    CERN Multimedia

    2004-01-01

    ACADEMIC TRAINING Françoise Benz tel. 73127 academic.training@cern.ch SUGGEST AND WIN! Its time to plan the 2004-2005 lecture series. From today until March 19 you have the chance to give your contribution to planning for next year's Academic Training Lecture Series. At the web site: http://cern.ch/Academic.Training/questionnaire you will find questionnaires proposing topics in high energy physics, applied physics and science and society. Answering the questionnaire will help ensure that the selected topics are as close as possible to your interests. In particular requests and comments from students will be much appreciated. To encourage your contribution, the AT Committee will reward one lucky winner with a small prize, a 50 CHF coupon for a book purchase at the CERN bookshop.

  4. Training System for the Expiration Training

    Science.gov (United States)

    Ogoshi, Yasuhiro; Nakai, Akio; Mitsuhashi, Yoshinori; Araki, Chikahiro

    For a speech therapist, the breathing method is one of the important techniques to train a person who has difficulty in speaking. Insufficient number of therapists makes it difficult to apply these breath training methods widely. Therefore, development of a new breath training method will be mandatory. With this reason, a new training system is developed and described in this paper. In this new method, expiration pattern of a speech therapist analyzing through an air flow sensor is constructed into visual graphic image in order to recognize expiration pattern easily. With experimental use of this system to without handicapped trainees, they could successfully imitate trainer's pronunciation easily. A person who has difficulty in speaking will be able to learn easily how to do expiration for speaking through visual pattern.

  5. Production and Characterization of Attosecond Bunch Trains

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Christopher M.S.; Colby, Eric; Ischebeck, Rasmus; McGuinness , Christopher; Nelson, Janice; Noble, Robert; Siemann, Robert H.; Spencer, James; Walz, Dieter; /SLAC; Plettner, Tomas; Byer, Robert L.; /Stanford U.

    2008-06-02

    We report the production of optically spaced attosecond microbunches produced by the inverse Free Electron Laser (IFEL) process. The IFEL is driven by a Ti:sapphire laser synchronized with the electron beam. The IFEL is followed by a magnetic chicane that converts the energy modulation into the longitudinal microbunch structure. The microbunch train is characterized by observing Coherent Optical Transition Radiation (COTR) at multiple harmonics of the bunching. The experimental results are compared with 1D analytic theory showing good agreement. Estimates of the bunching factors are given and correspond to a microbunch length of 350as fwhm. The formation of stable attosecond electron pulse trains marks an important step towards direct laser acceleration.

  6. Cryosurgery with pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    Charlotte S Daniels

    Full Text Available This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused

  7. Computer training aids for nuclear operator training

    International Nuclear Information System (INIS)

    The Royal Navy's Nuclear Propulsion School at HMS SULTAN which is responsible for training all ratings and officers who operate Submarine Pressurised Water Reactor plants, has available a varied selection of classroom simulator training aids as well as purpose built Submarine Manoeuvring Room simulators. The use of these classroom training aids in the twelve months prior to Autumn 1981 is discussed. The advantages and disadvantages of using relatively expensive computer based aids to support classroom instruction for students who do not investigate mathematically the dynamics of the Reactor Plant are identified. The conclusions drawn indicate that for students of limited academic ability the classroom simulators are disproportionately expensive in cost, maintenance load, and instructional time. Secondly, the experience gained in the use of the Manoeuvring Room Simulators to train future operators who have just finished the academic phase of their training is outlined. The possible pitfalls for the instructor are discussed and the lessons learnt, concluding that these simulators provide a valuable substitute for the live plant enabling trainees to be brought up to a common standard and reducing their on job training time to an acceptable level. (author)

  8. Pulse frequency classification based on BP neural network

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; WANG Xu; YANG Dan; FU Rong

    2006-01-01

    In Traditional Chinese Medicine (TCM), it is an important parameter of the clinic disease diagnosis to analysis the pulse frequency. This article accords to pulse eight major essentials to identify pulse type of the pulse frequency classification based on back-propagation neural networks (BPNN). The pulse frequency classification includes slow pulse, moderate pulse, rapid pulse etc. By feature parameter of the pulse frequency analysis research and establish to identify system of pulse frequency features. The pulse signal from detecting system extracts period, frequency etc feature parameter to compare with standard feature value of pulse type. The result shows that identify-rate attains 92.5% above.

  9. Treatment Pulse Application for Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Sun-Seob Choi

    2011-01-01

    Full Text Available Treatment and diagnosis can be made in difficult areas simply by changing the output pulse form of the magnetic stimulation device. However, there is a limitation in the range of treatments and diagnoses of a conventional sinusoidal stimulation treatment pulse because the intensity, width, and form of the pulse must be changed according to the lesion type. This paper reports a multidischarge method, where the stimulation coils were driven in sequence via multiple switching control. The limitation of the existing simple sinusoidal pulse form could be overcome by changing the intensity, width, and form of the pulse. In this study, a new sequential discharge method was proposed to freely alter the pulse width. The output characteristics of the stimulation treatment pulse were examined according to the trigger signal delay applied to the switch at each stage by applying a range of superposition pulses to the magnetic simulation device, which is widely used in industry and medicine.

  10. Exact Solutions to Short Pulse Equation

    Institute of Scientific and Technical Information of China (English)

    FU Zun-Tao; ZHENG Ming-Hua; LIU Shi-Kuo

    2009-01-01

    In this paper, dependent and independent variable transformations are introduced to solve the short pulse equation. It is shown that different kinds of solutions can be obtained to the short pulse equation.

  11. Nature of giant pulses in radio pulsars

    CERN Document Server

    Petrova, S A

    2006-01-01

    Formation of giant radio pulses is attributed to propagation effects in the plasma of pulsar magnetosphere. Induced scattering of radio waves by the plasma particles is found to lead to an efficient redistribution of the radio emission in frequency. With the steep spectrum of pulsar radiation, intensity transfer between the widely spaced frequencies may imply significant narrow-band amplification of the radiation. This may give rise to giant pulses. It is demonstrated that the statistics of giant pulse intensities observed can be reproduced if one take into account pulse-to-pulse fluctuations of the plasma number density and the original intensity. Polarization properties of the strongly amplified pulses, their location in the average pulse window and the origin of the nanostructure of giant pulses are discussed as well.

  12. Dispersion compensation in chirped pulse amplification systems

    Science.gov (United States)

    Bayramian, Andrew James; Molander, William A.

    2014-07-15

    A chirped pulse amplification system includes a laser source providing an input laser pulse along an optical path. The input laser pulse is characterized by a first temporal duration. The system also includes a multi-pass pulse stretcher disposed along the optical path. The multi-pass pulse stretcher includes a first set of mirrors operable to receive input light in a first plane and output light in a second plane parallel to the first plane and a first diffraction grating. The pulse stretcher also includes a second set of mirrors operable to receive light diffracted from the first diffraction grating and a second diffraction grating. The pulse stretcher further includes a reflective element operable to reflect light diffracted from the second diffraction grating. The system further includes an amplifier, a pulse compressor, and a passive dispersion compensator disposed along the optical path.

  13. Developing classification indices for Chinese pulse diagnosis

    CERN Document Server

    Shu, Jian-Jun

    2014-01-01

    Aim: To develop classification criteria for Chinese pulse diagnosis and to objectify the ancient diagnostic technique. Methods: Chinese pulse curves are treated as wave signals. Multidimensional variable analysis is performed to provide the best curve fit between the recorded Chinese pulse waveforms and the collective Gamma density functions. Results: Chinese pulses can be recognized quantitatively by the newly-developed four classification indices, that is, the wave length, the relative phase difference, the rate parameter, and the peak ratio. The new quantitative classification not only reduces the dependency of pulse diagnosis on Chinese physician's experience, but also is able to interpret pathological wrist-pulse waveforms more precisely. Conclusions: Traditionally, Chinese physicians use fingertips to feel the wrist-pulses of patients in order to determine their health conditions. The qualitative theory of the Chinese pulse diagnosis is based on the experience of Chinese physicians for thousands of year...

  14. Linear transformer driver for pulse generation

    Science.gov (United States)

    Kim, Alexander A; Mazarakis, Michael G; Sinebryukhov, Vadim A; Volkov, Sergey N; Kondratiev, Sergey S; Alexeenko, Vitaly M; Bayol, Frederic; Demol, Gauthier; Stygar, William A

    2015-04-07

    A linear transformer driver includes at least one ferrite ring positioned to accept a load. The linear transformer driver also includes a first power delivery module that includes a first charge storage devices and a first switch. The first power delivery module sends a first energy in the form of a first pulse to the load. The linear transformer driver also includes a second power delivery module including a second charge storage device and a second switch. The second power delivery module sends a second energy in the form of a second pulse to the load. The second pulse has a frequency that is approximately three times the frequency of the first pulse. The at least one ferrite ring is positioned to force the first pulse and the second pulse to the load by temporarily isolating the first pulse and the second pulse from an electrical ground.

  15. Mode-locked Yb-doped fiber laser emitting broadband pulses at ultra-low repetition rates

    CERN Document Server

    Bowen, Patrick; Provo, Richard; Harvey, John D; Broderick, Neil G R

    2016-01-01

    We report on an environmentally stable, Yb-doped, all-normal dispersion, mode-locked fibre laser that is capable of creating broadband pulses with ultra-low repetition rates. Specifically, through careful positioning of fibre sections in an all-PM-fibre cavity mode-locked with a nonlinear amplifying loop mirror, we achieve stable pulse trains with repetition rates as low as 506 kHz. The pulses have several nanojules of energy and are compressible down to ultrashort (< 500 fs) durations.

  16. Observation of reflection feedback induced the formation of bright-dark pulse pairs in an optically pumped semiconductor laser.

    Science.gov (United States)

    Tsou, C H; Liang, H C; Huang, K F; Chen, Y F

    2016-06-13

    It is experimentally demonstrated that the tiny reflection feedback can lead the optically pumped semiconductor laser (OPSL) to be operated in a self-mod-locked state with a pulse train of bright-dark pulse pairs. A theoretical model based on the multiple reflections in a phase-locked multi-longitudinal-mode laser is developed to confirm the formation of bright-dark pulse pairs. The present finding can offer an important insight into the temporal dynamics in mode-locked OPSLs. PMID:27410319

  17. Generation of millimeter-wave sub-carrier optical pulse by using a Fabry-Perot interferometer

    Institute of Scientific and Technical Information of China (English)

    Qing Ye; Ronghui Qu; Zujie Fang

    2007-01-01

    A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave (mm-wave) frequency modulation pulse by using a Fabry-Perot interferometer (FPI) for radio-over-fiber (ROF) system.It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot (F-P) cavity, and amplitude decay time and energy transfer efficiency are related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.

  18. Signal recognition efficiencies of artificial neural-network pulse-shape discrimination in HPGe 0νββ-decay searches

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, A.; Cossavella, F.; Majorovits, B.; Palioselitis, D.; Volynets, O. [Max-Planck-Institut fuer Physik, Munich (Germany)

    2015-07-15

    A pulse-shape discrimination method based on artificial neural networks was applied to pulses simulated for different background, signal and signal-like interactions inside a germanium detector. The simulated pulses were used to investigate variations of efficiencies as a function of used training set. It is verified that neural networks are well-suited to identify background pulses in true-coaxial high-purity germanium detectors. The systematic uncertainty on the signal recognition efficiency derived using signal-like evaluation samples from calibration measurements is estimated to be 5 %. This uncertainty is due to differences between signal and calibration samples. (orig.)

  19. Odor detection in Manduca sexta is optimized when odor stimuli are pulsed at a frequency matching the wing beat during flight.

    Directory of Open Access Journals (Sweden)

    Kevin C Daly

    Full Text Available Sensory systems sample the external world actively, within the context of self-motion induced disturbances. Mammals sample olfactory cues within the context of respiratory cycles and have adapted to process olfactory information within the time frame of a single sniff cycle. In plume tracking insects, it remains unknown whether olfactory processing is adapted to wing beating, which causes similar physical effects as sniffing. To explore this we first characterized the physical properties of our odor delivery system using hotwire anemometry and photo ionization detection, which confirmed that odor stimuli were temporally structured. Electroantennograms confirmed that pulse trains were tracked physiologically. Next, we quantified odor detection in moths in a series of psychophysical experiments to determine whether pulsing odor affected acuity. Moths were first conditioned to respond to a target odorant using Pavlovian olfactory conditioning. At 24 and 48 h after conditioning, moths were tested with a dilution series of the conditioned odor. On separate days odor was presented either continuously or as 20 Hz pulse trains to simulate wing beating effects. We varied pulse train duty cycle, olfactometer outflow velocity, pulsing method, and odor. Results of these studies, established that detection was enhanced when odors were pulsed. Higher velocity and briefer pulses also enhanced detection. Post hoc analysis indicated enhanced detection was the result of a significantly lower behavioral response to blank stimuli when presented as pulse trains. Since blank responses are a measure of false positive responses, this suggests that the olfactory system makes fewer errors (i.e. is more reliable when odors are experienced as pulse trains. We therefore postulate that the olfactory system of Manduca sexta may have evolved mechanisms to enhance odor detection during flight, where the effects of wing beating represent the norm. This system may even exploit

  20. Methods for High Power EM Pulse Measurement

    OpenAIRE

    Fiala, P.; Drexler, P.

    2006-01-01

    There are some suitable methods for the measurement of ultra-short solitary electromagnetic pulses that can be generated by high power pulsed generators. The measurement methods properties have to correspond to the fact whether we want to measure pulses of voltage, current or free-space electromagnetic wave. The need for specific measurement methods occurred by the development of high power microwave pulse generator. Applicable methods are presented in this paper. The method utilizing Faraday...

  1. Dynamic pulsing of a MOPA fiber laser

    Science.gov (United States)

    Romero, Rosa; Guerreiro, Paulo T.; Hendow, Sami T.; Salcedo, José R.

    2011-05-01

    Dynamic Pulsing is demonstrated using a pulsed MOPA fiber laser at 1064nm. The output of the MOPA laser is a pulsed profile consisting of a burst of closely spaced pulses. Tests were performed under several materials with pulse bursts ranging from 10ns to 1μs and operating from 500kHz down to single shot. In particular, percussion drilling in stainless steel is demonstrated showing improvements in quality and speed of the process. These profiles allow high flexibility and optimization of the process addressing the specificity of the end application. Dynamic Pulsing allows the same MOPA fiber laser to be used in diverse materials as well as different processes such us marking, drilling, scribing and engraving. The pulsed fiber laser used in this study is a MOPA-DY by Multiwave Photonics. It is based on a modulated seed laser followed by a series of fiber amplifiers and ending with an optically isolated collimator. This pulsed laser model has an output in such a way that each trigger produces a fast burst of pulses, with a repetition frequency within the burst of the order of tens of MHz. Within the burst it is possible to change the number of pulses, the individual pulse profile, burst pulse period and even to generate non-periodic burst pulse separations. The laser allows full freedom for all these combinations. The study here reported compares the impact of pulse peak power, number of pulses within a burst and the pulse burst period, on process quality (heat affected zone, debris, hole uniformity) and drilling yield.

  2. High Power Picosecond Laser Pulse Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  3. Team skills training

    International Nuclear Information System (INIS)

    Numerous reports and articles have been written recently on the importance of team skills training for nuclear reactor operators, but little has appeared on the practical application of this theoretical guidance. This paper describes the activities of the Training and Education Department at GPU Nuclear (GPUN). In 1987, GPUN undertook a significant initiative in its licensed operator training programs to design and develop initial and requalification team skills training. Prior to that time, human interaction skills training (communication, stress management, supervisory skills, etc.) focused more on the individual rather than a group. Today, GPU Nuclear conducts team training at both its Three Mile Island (YMI), PA and Oyster Creek (OC), NJ generating stations. Videotaped feedback is sued extensively to critique and reinforce targeted behaviors. In fact, the TMI simulator trainer has a built-in, four camera system specifically designed for team training. Evaluations conducted on this training indicated these newly acquired skills are being carried over to the work environment. Team training is now an important and on-going part of GPUN operator training

  4. Training needs assessment

    International Nuclear Information System (INIS)

    The one basic requirement which all educators and trainers agree upon as the basis for training is the need. A training need may be described as existing anytime an actual condition differs from a desired condition. In other words, when an employee fails to perform a task according to that person's job description, a training need is established. The training needs assessment process will identify the specific training required to perform a specific, desired task. Training needs must be identified, objectives written and appropriate curriculum developed which targets the specific needs of a job, unit or organization before one can truly say they they have a valid, cost-effective training program. A needs assessment is, therefore, paramount to and the foundation of the training process. The purposes of a training needs assessment are to: 1) Provide a deliberate and orderly process for planning and developing training programs which ensure instructional needs and objectives are met; and 2) Assure that personnel are taught, in a cost-effective way, the knowledge, skills and abilities essential to successful task performance

  5. Complementarity of long pulse and short pulse spallation sources

    International Nuclear Information System (INIS)

    The complementarity of short pulse spallation sources (SPSS) and steady state (CW) reactors is a widely accepted concept. SPSS and long pulse spallation sources (LPSS) are complementary in two ways: a) in their performance in neutron scattering experiments LPSS closely emulate CW reactors. In this respect two facets of the time-of-flight (TOF) monochromator method adequate for LPSS will be discussed: the superiority of the TOF approach to the crystal monochromator method in high resolution powder diffraction, and the novel technique of repetition rate multiplication in TOF spectroscopy, b) LPSS combined with adequate chopper systems can also emulate SPSS in a number of applications. It will be shown that the LPSS method of producing short neutron pulses is more efficient for cold and thermal neutrons (below an energy of about 100 MeV), while SPSS is the more favourable approach for hot, epithermal neutrons, i.e. in the slowing down regime in contrast to the moderated regime. These two aspects of complementarity of LPSS and SPSS lead to the conclusions that for about 75% of the spectrum of neutron scattering experiments as known of today the LPSS approach is the most advantageous one with a feasible neutron intensity exceeding that available at ILL by a factor of about 30, while for the remaining 25% of applications the SPSS technique is superior with a well-known potential of a similar gain over present day performances. (author) 7 figs., 6 refs

  6. Ambient Intelligence Systems for Personalized Sport Training

    Directory of Open Access Journals (Sweden)

    Daniel González-Jiménez

    2010-03-01

    Full Text Available Several research programs are tackling the use of Wireless Sensor Networks (WSN at specific fields, such as e-Health, e-Inclusion or e-Sport. This is the case of the project “Ambient Intelligence Systems Support for Athletes with Specific Profiles”, which intends to assist athletes in their training. In this paper, the main developments and outcomes from this project are described. The architecture of the system comprises a WSN deployed in the training area which provides communication with athletes’ mobile equipments, performs location tasks, and harvests environmental data (wind speed, temperature, etc.. Athletes are equipped with a monitoring unit which obtains data from their training (pulse, speed, etc.. Besides, a decision engine combines these real-time data together with static information about the training field, and from the athlete, to direct athletes’ training to fulfill some specific goal. A prototype is presented in this work for a cross country running scenario, where the objective is to maintain the heart rate (HR of the runner in a target range. For each track, the environmental conditions (temperature of the next track, the current athlete condition (HR, and the intrinsic difficulty of the track (slopes influence the performance of the athlete. The decision engine, implemented by means of (m; s-splines interpolation, estimates the future HR and selects the best track in each fork of the circuit. This method achieves a success ratio in the order of 80%. Indeed, results demonstrate that if environmental information is not take into account to derive training orders, the success ratio is reduced notably.

  7. Ambient Intelligence Systems for Personalized Sport Training

    Science.gov (United States)

    Vales-Alonso, Javier; López-Matencio, Pablo; Gonzalez-Castaño, Francisco J.; Navarro-Hellín, Honorio; Baños-Guirao, Pedro J.; Pérez-Martínez, Francisco J.; Martínez-Álvarez, Rafael P.; González-Jiménez, Daniel; Gil-Castiñeira, Felipe; Duro-Fernández, Richard

    2010-01-01

    Several research programs are tackling the use of Wireless Sensor Networks (WSN) at specific fields, such as e-Health, e-Inclusion or e-Sport. This is the case of the project “Ambient Intelligence Systems Support for Athletes with Specific Profiles”, which intends to assist athletes in their training. In this paper, the main developments and outcomes from this project are described. The architecture of the system comprises a WSN deployed in the training area which provides communication with athletes’ mobile equipments, performs location tasks, and harvests environmental data (wind speed, temperature, etc.). Athletes are equipped with a monitoring unit which obtains data from their training (pulse, speed, etc.). Besides, a decision engine combines these real-time data together with static information about the training field, and from the athlete, to direct athletes’ training to fulfill some specific goal. A prototype is presented in this work for a cross country running scenario, where the objective is to maintain the heart rate (HR) of the runner in a target range. For each track, the environmental conditions (temperature of the next track), the current athlete condition (HR), and the intrinsic difficulty of the track (slopes) influence the performance of the athlete. The decision engine, implemented by means of (m, s)-splines interpolation, estimates the future HR and selects the best track in each fork of the circuit. This method achieves a success ratio in the order of 80%. Indeed, results demonstrate that if environmental information is not take into account to derive training orders, the success ratio is reduced notably. PMID:22294931

  8. REFLECTANCE PULSE OXIMETRY IN FETAL LAMBS

    NARCIS (Netherlands)

    DASSEL, AC; GRAAFF, R; AARNOUDSE, JG; ELSTRODT, JM; HEIDA, P; KOELINK, MH; DEMUL, FF; GREVE, J

    1992-01-01

    Transmission pulse oximetry is used for monitoring in many clinical settings. However, for fetal monitoring during labor and in situations with poor peripheral perfusion, transmission pulse oximetry cannot be used. Therefore, we developed a reflectance pulse oximeter, which uses the relative intensi

  9. <3> OMEGA pulse-forming network

    CERN Multimedia

    1974-01-01

    Adjustement of the 3 W pulse-forming network of the SPS beam dumping system. When charged at 60 kV, this PFN gives 10 kA, 25 ms current pulses, with oscillations, superimposed on the pulse flat top, of an amplitude of +/- 1 Ka.

  10. Double pulse Thomson scattering system at RTP

    NARCIS (Netherlands)

    Beurskens, M. N. A.; Barth, C. J.; Chu, C.C.; Donne, A. J. H.; Herranz, J. A.; Cardozo, N. J. L.; van der Meiden, H. J.; Pijper, F.J.

    1997-01-01

    In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10-800 mu s, max. 2x12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator fo

  11. Perceptions of European stakeholders of pulse fishing

    NARCIS (Netherlands)

    Kraan, M.L.; Trapman, B.K.; Rasenberg, M.M.M.

    2015-01-01

    This research project examines the concerns and questions of European stakeholders about pulse fishing, in order to assess to what extent the knowledge agenda on pulse fishing covers these issues. To get a first impression of the concerns about pulse fishing, and to get an idea of the stakeholders t

  12. A transformer of closely spaced pulsed waveforms

    Science.gov (United States)

    Niedra, J.

    1970-01-01

    Passive circuit, using diodes, transistors, and magnetic cores, transforms the voltage of repetitive positive or negative pulses. It combines a pulse transformer with switching devices to effect a resonant flux reset and can transform various pulsed waveforms that have a nonzero average value and are relatively cosely spaced in time.

  13. Cross cultural training

    Institute of Scientific and Technical Information of China (English)

    王容

    2014-01-01

    Under the background of economic globalization, the globalization of human resources management determines the success of enterprise success or failure, in a sense, human resource is the first resource of the enterprise. Cross-cultural training is the core problems in global human resource management, it can let employees quickly familiar with the company's business and job content, understand the enterprise culture and core idea, to play a huge role in promoting enterprise development. Therefore, strengthen enterprise staff training, improve the comprehensive quality of enterprise personnel has become the urgent problems now in the process of enterprise development. Articles in samsung electronics of South Korea, for example, introduces the samsung especial y cross-cultural training content, training method and training effect. And analysis of cross-cultural training impact in the global business team and establish business relationship.

  14. Language Training: Anglais

    CERN Multimedia

    Françoise Benz

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Writing Professional Documents in English This course is designed for people with a good level of spoken English. Duration: 2 hours a week between 26 April and 1 July 2004. Timetable: Thursdays 12.00 to 14.00 Price: 440 CHF (for 8 students and 20 hours) For registration and further information, please consult our Web pages: http://cern.ch/Training or contact Mr. Liptow: tel. 72957 FORMATION EN LANGUES LANGUAGE TRAINING Françoise Benz 73127 language.training@cern.ch

  15. Safety training news

    CERN Multimedia

    Safety Training, HSE Unit

    2014-01-01

      SELF-RESCUE MASK The "Self-Rescue Mask" face-to-face training course has been replaced by a revised version. This measure concerns both the initial and the refresher course. For personnel who have successfully attended the initial or refresher Self-Rescue Mask training within the last three years, their Self-Rescue Mask training will still be valid.  The course description and registration form can be found in the training catalogue on the Safety Training Service’s website or catalogue. The Self-Rescue Mask training course is a mandatory prerequisite for following the new "Portable ODH Detector" e-learning course.   PORTABLE ODH DETECTOR A new e-learning awareness course, "Portable ODH Detector", is available via the SIR application on CERN’s intranet. Personnel requiring a portable ODH detector of the DRÄGER x-am 5000 type to allowed access th...

  16. Academic Training: String Theory

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 6, 7, 8, 9 and 10 June from 11.00 to 12.00 hrs - Auditorium, bldg. 500 on 6, 7, 8 & 10 June, TH Auditorium, bldg. 4, 3rd floor on 9 June String Theory by C. Johnson / Univ. of Southern California, USA ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt.

  17. CW seeded optical parametric amplifier providing wavelength and pulse duration tunable nearly transform limited pulses.

    Science.gov (United States)

    Hädrich, S; Gottschall, T; Rothhardt, J; Limpert, J; Tünnermann, A

    2010-02-01

    An optical parametric amplifier that delivers nearly transform limited pulses is presented. The center wavelength of these pulses can be tuned between 993 nm and 1070 nm and, at the same time, the pulse duration is varied between 206 fs and 650 fs. At the shortest pulse duration the pulse energy was increased up to 7.2 microJ at 50 kHz repetition rate. Variation of the wavelength is achieved by applying a tunable cw seed while the pulse duration can be varied via altering the pump pulse duration. This scheme offers superior flexibility and scaling possibilities.

  18. Off-resonance effects in (14)N NQR signals from the pulsed spin-locking (PSL) and three-pulse echo sequence; a study for monoclinic TNT.

    Science.gov (United States)

    Smith, John A S; Rowe, Michael D; Althoefer, Kaspar; Peirson, Neil F; Barras, Jamie

    2015-10-01

    In NQR detection applications signal averaging by the summation of rapidly regenerated signals from multiple pulse sequences of the pulsed spin-locking (PSL) type is often used to improve sensitivity. It is important to characterise and if possible minimise PSL sequence off-resonance effects since they can make it difficult to optimise detection performance. We illustrate this with measurements of the variation of the decay time T2e and the amplitude of PSL signal trains with pulse spacing and excitation offset frequency for the 870 kHz ν+(14)N NQR line of monoclinic TNT under carefully stabilised temperature conditions. We have also carried out a similar study of signals from monoclinic TNT and 1H-1,2,3-triazole generated by a three-pulse echo sequence and the results are shown to agree well with a theoretical treatment appropriate to polycrystalline NQR samples such as TNT for which spin I=1, asymmetry parameter η≠0 and T1≫T2. Based on this theory we derive simple models for calculating TNT PSL signal trains and hence the pulse spacing and off-resonance dependence of signal amplitude and T2e which we compare to our experimental data. We discuss the influence of PSL echo summation on off-resonance effects in detected signal intensity and show how a phase-alternated multiple pulse sequence can be used in combination with the PSL sequence to eliminate variation in detection performance due to off-resonance effects.

  19. Pulse Propagation on close conductors

    CERN Document Server

    Dieckmann, A

    2001-01-01

    The propagation and reflection of arbitrarily shaped pulses on non-dispersive parallel conductors of finite length with user defined cross section is simulated employing the discretized telegraph equation. The geometry of the system of conductors and the presence of dielectric material determine the capacities and inductances that enter the calculation. The values of these parameters are found using an iterative Laplace equation solving procedure and confirmed for certain calculable geometries including the line charge inside a box. The evolving pulses and the resulting crosstalk can be plotted at any instant and - in the Mathematica notebook version of this report - be looked at in an animation. As an example a differential pair of microstrips as used in the ATLAS vertex detector is analysed.

  20. Pulsed metallic-plasma generators.

    Science.gov (United States)

    Gilmour, A. S., Jr.; Lockwood, D. L.

    1972-01-01

    A pulsed metallic-plasma generator is described which utilizes a vacuum arc as the plasma source. The arc is initiated on the surface of a consumable cathode which can be any electrically conductive material. Ignition is accomplished by using a current pulse to vaporize a portion of a conductive film on the surface of an insulator separating the cathode from the ignition electrode. The film is regenerated during the ensuing arc. Over 100 million ignition cycles have been accomplished by using four 0.125-in. diameter zinc cathodes operating in parallel and high-density aluminum-oxide insulators. Among the applications being investigated for the generator are metal deposition, vacuum pumping, electric propulsion, and high-power dc arc interruption.