Journal articles: 'Light pulser'

1

Ponikvar, D. "A Simple Subnanosecond Light Pulser." IEEE Transactions on Nuclear Science 59, no. 6 (December 2012): 3218–20. http://dx.doi.org/10.1109/tns.2012.2220979.

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Clark, P. J. "The BaBar calorimeter light pulser system." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 461, no. 1-3 (April 2001): 348–50. http://dx.doi.org/10.1016/s0168-9002(00)01241-9.

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Lubsandorzhiev, B. K., and Y. E. Vyatchin. "Studies of ``Kapustinsky's'' light pulser timing characteristics." Journal of Instrumentation 1, no. 06 (June 21, 2006): T06001. http://dx.doi.org/10.1088/1748-0221/1/06/t06001.

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Kapustinsky, J. S., R. M. DeVries, N. J. DiGiacomo, W. E. Sondheim, J. W. Sunier, and H. Coombes. "A fast timing light pulser for scintillation detectors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 241, no. 2-3 (December 1985): 612–13. http://dx.doi.org/10.1016/0168-9002(85)90622-9.

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Grummer, A., M. R. Hoeferkamp, and S. Seidel. "A radiation tolerant light pulser for particle physics applications." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 883 (March 2018): 29–32. http://dx.doi.org/10.1016/j.nima.2017.11.020.

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Rongen, M., and M. Schaufel. "Design and evaluation of a versatile picosecond light pulser." Journal of Instrumentation 13, no. 06 (June 5, 2018): P06002. http://dx.doi.org/10.1088/1748-0221/13/06/p06002.

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Ciholas, M. E., and P. M. Wilt. "A pulser circuit for measuring the speed of light." American Journal of Physics 55, no. 9 (September 1987): 853–54. http://dx.doi.org/10.1119/1.15011.

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Zabierowski, J., and J. Rachowski. "The Light-Pulser Monitoring System for the WASA detector facility." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 606, no. 3 (July 2009): 411–18. http://dx.doi.org/10.1016/j.nima.2009.05.010.

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Benulis, C. A., and W. K. McFarlane. "A light pulser system for testing photomultiplier-based counter systems." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 240, no. 1 (October 1985): 135–38. http://dx.doi.org/10.1016/0168-9002(85)90396-1.

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Margulies, S., and J. Ozelis. "A Fast VUV Light Pulser for Testing Ring-Imaging Cerenkov Counters." IEEE Transactions on Nuclear Science 33, no. 1 (1986): 306–9. http://dx.doi.org/10.1109/tns.1986.4337106.

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Fyodorov, A., M. Korzhik, A. Lopatik, and O. Missevitch. "LED light pulser for high precision monitoring of the scintillation calorimeter energy scale." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 413, no. 2-3 (August 1998): 352–56. http://dx.doi.org/10.1016/s0168-9002(98)00275-7.

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Berger, J., M. Bermond, P. Besson, J. Favier, H. Pessard, and M. Poulet. "Photomultiplier gain monitoring at the one percent level with a blue light pulser." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 279, no. 1-2 (July 1989): 343–49. http://dx.doi.org/10.1016/0168-9002(89)91104-2.

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Kato, Chihiro, Akira Yoneda, Kazuoki Munakata, Takashi Imai, and Tsuyoshi Kohno. "Test of Two-Dimensional Position Sensitive Silicon Detector for Cosmic Ray Telescope by a Light Pulser." Japanese Journal of Applied Physics 30, Part 1, No. 12A (December 15, 1991): 3549–50. http://dx.doi.org/10.1143/jjap.30.3549.

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Mickaliger, Mitchell B., Ben W. Stappers, Cees G. Bassa, and Aldus G. Fletcher. "1,000,000 Giant Pulses from the Crab Pulsar." Proceedings of the International Astronomical Union 13, S337 (September 2017): 380–81. http://dx.doi.org/10.1017/s174392131700922x.

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AbstractThe Crab pulsar was first detected soon after the discovery of pulsars, and has long been studied for its unique traits. One of these traits, giant pulses that can be upwards of 1000 times brighter than the average pulse, was key to the Crab’s initial detection. Giant pulses are only seen in a few pulsars, and their energy distributions distinguish them from normal pulsed emission. There have been many studies over a period of decades to measure the power-law slope of these energy distributions, which provide insight into the possible emission mechanism of these giant pulses.The 42-foot telescope at Jodrell Bank Observatory monitors the Crab pulsar on a daily basis. We have single-pulse data dating back to 2012, containing roughly 1,000,000 giant pulses, the largest sample of Crab giant pulses to date. This large set of giant pulses allows us to do a range of science, including pulse-width studies and in-depth studies of giant-pulse energy distributions. The latter are particularly interesting, as close inspection of the high-energy tail of the energy distribution allows us to investigate the detectability of extragalactic giant-pulsing pulsars. Also, by calculating rates from these energy distributions, we may be able to shed light on a possible link between Fast Radio Bursts and giant pulses.

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Tomasevic, I. "The effect of intense light pulses on the sensory quality and instrumental color of meat from different animal breeds." Biotehnologija u stocarstvu 31, no. 2 (2015): 273–81. http://dx.doi.org/10.2298/bah1502273t.

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Intense light pulses (ILP) are an emerging processing technology, which has a potential to decontaminate food products. The light generated by ILP lamps consists of a continuum broadband spectrum from deep UV to the infrared, especially rich in UV range below 400 nm, which is germicidal. Evaluation of the effect of intense light pulses (ILP) on sensory quality of meat, game and poultry was performed using two kinds of red meat (beef and pork), two kinds of poultry (chicken and turkey) and three game meat samples (deer, rabbit and kangaroo). All the samples were treated with 1 and 5 light pulses (pulse duration of 300 ?s and pulse intensity of 3.4 J/cm2) at a rate of one pulse per 2 seconds. Sensory quality changes induced by intense light pulses were different and depended on animal species, type of meat and ILP dose applied. Only the odour of all the meat, poultry and game samples suffered significant changes after the pulsed light treatment. Of all kinds of meat investigated only turkey received scores below the good quality grade after the treatment. Instrumental colour values remained unaffected in chicken and rabbit meat samples while higher doses of ILP significantly compromised both redness and yellowness only in pork and turkey meat.

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Rowan, N. J., S. J. MacGregor, J. G. Anderson, R. A. Fouracre, L. McIlvaney, and O. Farish. "Pulsed-Light Inactivation of Food-Related Microorganisms." Applied and Environmental Microbiology 65, no. 3 (March 1, 1999): 1312–15. http://dx.doi.org/10.1128/aem.65.3.1312-1315.1999.

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ABSTRACT The effects of high-intensity pulsed-light emissions of high or low UV content on the survival of predetermined populations ofListeria monocytogenes, Escherichia coli,Salmonella enteritidis, Pseudomonas aeruginosa,Bacillus cereus, and Staphylococcus aureus were investigated. Bacterial cultures were seeded separately on the surface of tryptone soya-yeast extract agar and were reduced by up to 2 or 6 log10 orders with 200 light pulses (pulse duration, ∼100 ns) of low or high UV content, respectively (P < 0.001).

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Canal, M. M., and H. D. Piggins. "Resetting of the hamster circadian system by dark pulses." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 290, no. 3 (March 2006): R785—R792. http://dx.doi.org/10.1152/ajpregu.00548.2005.

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Circadian rhythms of animals are reset by exposure to light as well as dark; however, although the parameters of photic entrainment are well characterized, the phase-shifting actions of dark pulses are poorly understood. Here, we determined the tonic and phasic effects of short (0.25 h), moderate (3 h), and long (6–9 h) duration dark pulses on the wheel-running rhythms of hamsters in constant light. Moderate- and long-duration dark pulses phase dependently reset behavioral rhythms, and the magnitude of these phase shifts increased as a function of the duration of the dark pulse. In contrast, the 0.25-h dark pulses failed to evoke consistent effects at any circadian phase tested. Interestingly, moderate- and long-dark pulses elevated locomotor activity (wheel-running) on the day of treatment. This induced wheel-running was highly correlated with phase shift magnitude when the pulse was given during the subjective day. This, together with the finding that animals pulsed during the subjective day are behaviorally active throughout the pulse, suggests that both locomotor activity and behavioral activation play an important role in the phase-resetting actions of dark pulses. We also found that the robustness of the wheel-running rhythm was weakened, and the amount of wheel-running decreased on the days after exposure to dark pulses; these effects were dependent on pulse duration. In summary, similarly to light, the resetting actions of dark pulses are dependent on both circadian phase and stimulus duration. However, dark pulses appear more complex stimuli, with both photic and nonphotic resetting properties.

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Wang, Juntao, Yuanyuan Qi, Junchao Lu, Xiaodong Li, and Junfei Wang. "Optimization of high-power Er/Yb co-doped fiber amplifiers for dual-band pulse amplification." Modern Physics Letters B 32, no. 22 (August 7, 2018): 1850263. http://dx.doi.org/10.1142/s0217984918502639.

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In this paper, high-power pulse-pumped erbium–ytterbium co-doped fiber amplifiers (EYDFAs) for simultaneous amplification of low-repetition rate pulses in the 1.0 [Formula: see text]m and 1.5 [Formula: see text]m bands are numerically investigated. The influences of the peak power and pulse-width of the pump and time delay between the pump and signal pulses on the performance of the amplifier are systematically analyzed. The results show that a pulse-pumped EYDFA is capable of simultaneously amplifying dual-band pulses. The optimal pulse-width of the pump is mainly determined by the allowable power of the backward Yb amplified spontaneous emission (ASE). By simply adjusting the time delay between the pump and signal pulses, the power ratio of the dual-band signals can be easily changed. Such kind of dual-band-pulsed EYDFAs have great potential applications in fields such as the generation of visible or mid-infrared light by nonlinear frequency conversion, counter stealth Lidar, etc.

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Wang, Min, Jie Chen, Niu Liu, and Ya Wang. "Inter-Pulse Spectroscopy Based on Room-Temperature Pulsed Quantum-Cascade Laser for N₂O Detection." Applied Mechanics and Materials 128-129 (October 2011): 607–10. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.607.

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Mid-infrared lasers are very suitable for high-sensitive trace-gases detection for their wavelengths cover the fundamental absorption lines of most gases. Quantum-cascade (QC) lasers have been demonstrated to be ideal light sources with its special power, tuning and capability of operating in room-temperature. All these merits make it appropriate for the high resolution spectrum analysis. The absorption spectrum monitoring technology based on the QC laser pulsed operating in the room temperature, combining with the strong absorption of the gas molecule in the basic frequency, has become an effective way to monitor the trace gas with the characteristic of high sensitivity, good selectivity and fast response. In this paper, the inter-pulse spectroscopy based on a room-temperature distributed-feedback pulsed QC laser was introduced. Our approach to trace gas monitoring with QC lasers relies on short current pulses which are designed to produce even shorter light pulses. Each pulse corresponds to a single point in a spectrum. The N2O absorption spectrum centered at 2178.2cm-1was also obtained.

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Harding, Alice K., Mark S. Strickman, Carl Gwinn, P. McCulloch, and D. Moffet. "RXTE Observations of the Vela Pulsar: The X-ray-Optical Connection." International Astronomical Union Colloquium 177 (2000): 331–34. http://dx.doi.org/10.1017/s025292110005990x.

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AbstractWe report on our analysis of a 300 ks observation of the Vela pulsar with the Rossi X-Ray Timing Explorer (RXTE). The double-peaked, pulsed emission at 2 - 30 keV, which we had previously detected during a 93 ks observation, is confirmed with much improved statistics. There is now clear evidence, both in the spectrum and the light curve, that the emission in the RXTE band is a blend of two separate components. The spectrum of the harder component connects smoothly with the OSSE, COMPTEL and EGRET spectrum and the peaks in the light curve are in phase coincidence with those of the high-energy light curve. The spectrum of the softer component is consistent with an extrapolation to the pulsed optical flux, and the second RXTE pulse is in phase coincidence with the second optical peak. In addition, we see a peak in the 2-8 keV RXTE pulse profile at the radio phase.

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PÉTRI, JÉRÔME, and JOHN G. KIRK. "PULSED HIGH-ENERGY EMISSION AND PHASE-RESOLVED SPECTRA BY INVERSE COMPTON SCATTERING IN A PULSAR STRIPED WIND." International Journal of Modern Physics D 17, no. 10 (September 2008): 1969–76. http://dx.doi.org/10.1142/s0218271808013649.

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To date, seven gamma-ray pulsars are known, showing pulsed emission up to tens of GeV and associated light-curves with a double-pulse structure. We study this pulsed high-energy emission in the framework of the striped wind model. By numerical integration of the time-dependent emissivity in the current sheets, we compute the phase-dependent spectral variability of the inverse Compton radiation. Several light curves and spectra are presented. The pulses are a direct consequence of relativistic beaming. Our model is able to explain some of the high-energy (10 MeV–10 GeV) spectral features and behavior of several gamma-ray pulsars, such as Geminga and Vela.

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Tokuda, T., T. Matsui, and H. Yano. "Effects of light and food on plasma leptin concentrations in ewes." Animal Science 71, no. 2 (October 2000): 235–42. http://dx.doi.org/10.1017/s1357729800055065.

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AbstractPlasma leptin concentration shows pulsatility and diurnal rhythm in humans. However, there are few reports concerning the 24-h profile of circulating leptin levels in ruminants. Five crossbred ewes were housed in metabolism cages under a 1-h light-dark cycle. The ewes were offered alfalfa hay daily to meet their energy requirement. Blood samples were collected at 15-min intervals for 24 h. Plasma leptin concentrations were determined using a radioimmunoassay and the profile of plasma leptin levels was analysed by the PULSAR algorithmic program for detecting pulse. Plasma leptin concentration changed in a pulsatile fashion. The mean leptin concentration was 2·93 ng/ml. The mean pulse frequency was 4·8 pulses per day and the mean pulse amplitude was 0·67 ng/ml with an average pulse length of 1:13 h. Plasma leptin level was not affected by feeding or lighting cycle. These results indicate that plasma leptin level in sheep shows pulsatility but diurnal rhythm is not exhibited.

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Vimont, Allison, Ismaïl Fliss, and Julie Jean. "Efficacy and Mechanisms of Murine Norovirus Inhibition by Pulsed-Light Technology." Applied and Environmental Microbiology 81, no. 8 (February 13, 2015): 2950–57. http://dx.doi.org/10.1128/aem.03840-14.

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ABSTRACTPulsed light is a nonthermal processing technology recognized by the FDA for killing microorganisms on food surfaces, with cumulative fluences up to 12 J cm−2. In this study, we investigated its efficacy for inactivating murine norovirus 1 (MNV-1) as a human norovirus surrogate in phosphate-buffered saline, hard water, mineral water, turbid water, and sewage treatment effluent and on food contact surfaces, including high-density polyethylene, polyvinyl chloride, and stainless steel, free or in an alginate matrix. The pulsed-light device emitted a broadband spectrum (200 to 1,000 nm) at a fluence of 0.67 J cm−2per pulse, with 2% UV at 8 cm beneath the lamp. Reductions in viral infectivity exceeded 3 log10in less than 3 s (5 pulses; 3.45 J cm−2) in clear suspensions and on clean surfaces, even in the presence of alginate, and in 6 s (11 pulses; 7.60 J cm−2) on fouled surfaces except for stainless steel (2.6 log10). The presence of protein or bentonite interfered with viral inactivation. Analysis of the morphology, the viral proteins, and the RNA integrity of treated MNV-1 allowed us to elucidate the mechanisms involved in the antiviral activity of pulsed light. Pulsed light appeared to disrupt MNV-1 structure and degrade viral protein and RNA. The results suggest that pulsed-light technology could provide an effective alternative means of inactivating noroviruses in wastewaters, in clear beverages, in drinking water, or on food-handling surfaces in the presence or absence of biofilms.

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Pyslar, I. V., V. V. Brailovsky, M. G. Rozhdestvenska, and M. M. Ivanchuk. "CAPABILITIES OF APPLYING VISIBLE LIGHT RAYS IN THE SYSTEMS OF HIDDEN INFORMATION TRANSMITTING." «System analysis and applied information science», no. 1 (June 12, 2018): 27–36. http://dx.doi.org/10.21122/2309-4923-2018-1-27-36.

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Security In the paper some aspects of visible light pulses using for hidden information transmitting are considered. We have investigated perception of the human vision to visual light pulses which have different power and frequency. It is established that pulsed light source becomes invisible at certain ratio of radiating light stream and ambient light level (background lighting (BL)). For example, in the case of background lighting E = 400 lx light pulses following with frequency 50 Hz are invisible when their power is less than 0.12 W. In the paper we represented experimental frequency dependence of the power of light pulses which are invisible for human eye at BL preset level.To eliminate the influence of distracting and masking factors (for example, BL pulsations) we offer to choose LED matrixes powered by stabilized adjustable DC power supply unit as an optimal BL source. Based on experimental data about current and temperature dependences of light stream power and LED matrix radiation spectra we developed a method of assignment of BL level by changing LED current. Approximating equation for dependence of light stream quantity versus LED current in the case of thermostatting is obtained. Temperature self-regulation effect of the heater, which has positive temperature coefficient of resistance, can satisfactorily solve the problem of temperature stabilization of LED background lighting source. In the case of thermostat heater made from material with positive temperature coefficient of resistance 0.48 K-1 the change of LED matrix temperature was 7 times less than without thermostat.To provide research in wide frequency and duration ranges of pulse sequences (10–3–103 Hz and 10–7–1 s) a pulse generator was developed and made using microcontroller PIC18F2550.

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Main, Robert, and Marten H. van Kerkwijk. "Mapping the Emission Location of the Crab Pulsar’s Giant Pulses." Proceedings of the International Astronomical Union 13, S337 (September 2017): 83. http://dx.doi.org/10.1017/s1743921317009176.

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AbstractThe Crab pulsar has a striking radio profile, dominated by two pulse components (the main pulse and interpulse) which are comprised of giant pulses. These pulses are randomly occurring, they extend to extremely high flux densities, and are closely aligned with emission across the entire electromagnetic spectrum. The Crab, like many pulsars, exhibits scintillation – a pattern in frequency and time arising from interfering scattered images. The pattern varies with location, with the physical scale over which it changes by order unity corresponding to the spatial resolution of the scattering surface. For the Crab, the scattering is in the nebula and the estimated spatial resolution is of order the light cylinder radius. Comparing scintillation spectra of the two components, we infer a difference in physical location of the same order.

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Demirci, A., and L. Panico. "Pulsed Ultraviolet Light." Food Science and Technology International 14, no. 5 (October 2008): 443–46. http://dx.doi.org/10.1177/1082013208098816.

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Pulsed Ultraviolet (UV)-Light is an emerging processing technology, which has a potential to decontaminate food products. The light generated by pulsed UV lamps consists of a continuum broadband spectrum from deep UV to the infrared, especially rich in UV range below 400 nm, which is germicidal. In pulsed UV-light system, UV-light is pulsed several times per second and each pulse lasts between 100 ns and 2ms. The pulsed UV-light has a modest energy input which can yield high peak power dissipation. Many researchers have demonstrated the effectiveness of pulsed UV-light on microbial loads on food surfaces. In this paper, various applications of pulsed UV-light treatment of foods found in the literature as well as future research needs will be discussed.

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Sang, Pil, Junseok Heo, Hui Park, and Hyoung Baac. "Photoacoustic Energy Sensor for Nanosecond Optical Pulse Measurement." Sensors 18, no. 11 (November 11, 2018): 3879. http://dx.doi.org/10.3390/s18113879.

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We demonstrate a photoacoustic sensor capable of measuring high-energy nanosecond optical pulses in terms of temporal width and energy fluence per pulse. This was achieved by using a hybrid combination of a carbon nanotube-polydimethylsiloxane (CNT-PDMS)-based photoacoustic transmitter (i.e., light-to-sound converter) and a piezoelectric receiver (i.e., sound detector). In this photoacoustic energy sensor (PES), input pulsed optical energy is heavily absorbed by the CNT-PDMS composite film and then efficiently converted into an ultrasonic output. The output ultrasonic pulse is then measured and analyzed to retrieve the input optical characteristics. We quantitatively compared the PES performance with that of a commercial thermal energy meter. Due to the efficient energy transduction and sensing mechanism of the hybrid structure, the minimum-measurable pulsed optical energy was significantly lowered, ~157 nJ/cm2, corresponding to 1/760 of the reference pyroelectric detector. Moreover, despite the limited acoustic frequency bandwidth of the piezoelectric receiver, laser pulse widths over a range of 6–130 ns could be measured with a linear relationship to the ultrasound pulse width of 22–153 ns. As CNT has a wide electromagnetic absorption spectrum, the proposed pulsed sensor system can be extensively applied to high-energy pulse measurement over visible through terahertz spectral ranges.

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Andriychuk, V. A., M. S. Nakonechny, Y. M. Osadtsa, and Y. O. Filiuk. "BEHAVIOR OF LED LIGHT SOURCES IN PULSE POWER." Tekhnichna Elektrodynamika 2021, no. 1 (January 14, 2021): 68–72. http://dx.doi.org/10.15407/techned2021.01.068.

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The researches results of the energy and dynamic characteristics for FYL-3014 and ARPL-1W LEDs with different spectral radiation when voltage rectangular pulses feds to LEDs are presented in the paper. On the basis of obtained oscilograms it is established that electrical circuits of pulsed supply of the LEDs contain hidden reactive elements of inductive and capacitive nature. The substitution schemes are proposed for these circuits and their parameters have been determined. In substitution schemes that are proposed for these circuits the LED is represented by a parallel RC link, the active component of which is determined by the heterojunction's active region resistance, and the reactive one by a capacity that is equal diffuse capacity of transition. On the basis of analysis of obtained transient processes equations for these circles it established the attenuation coefficient's dependence on the resistance of the heterojunction's active region. The influence of pulse frequency on the LEDs energy efficiency has been investigated. It is established that the maximum pulse frequency of the FYL-3014 and ARPL-1W LEDs is equal 700 kHz. References 12, figures 6.

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Jiang, Jianwei, Shaojuan Liu, Chunlei Wang, and Hongyan Zhang. "Overcoming Multidrug Resistance by On-Demand Intracellular Release of Doxorubicin and Verapamil." Journal of Nanomaterials 2018 (May 31, 2018): 1–7. http://dx.doi.org/10.1155/2018/3568190.

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Multidrug resistance (MDR) is one of the major obstacles to the successful application of cancer chemotherapy. Herein, we developed light-responsive doxorubicin-and-verapamil-coencapsulated gold liposomes to overcome MDR. Upon ns-pulsed laser irradiation, the highly confined thermal effect increased the permeability of the phospholipid bilayer, triggering the release of doxorubicin and verapamil, leading to high concentrations in cells. Free verapamil efficiently inhibited the membrane multidrug resistance proteins (MRPs), while the high concentration of doxorubicin saturated MRPs, thus overcoming MDR. We showed that nanosecond- (ns-) pulsed laser- (532 nm, 6 ns) induced doxorubicin release from gold liposomes depended on laser fluence and pulse number. More than 58% of the doxorubicin was released with a 10-pulse irradiation (100 mJ/cm2). Furthermore, ns laser pulses also liberated doxorubicin from endocytosed gold liposomes into the cytosol in MDA-MB-231-R cancer cells. The cytotoxicity of doxorubicin coencapsulated with verapamil was significantly enhanced upon laser irradiation. This study suggested that light-triggered on-demand release of chemotherapeutic agents and MRP inhibitors could be used advantageously to overcome multidrug resistance.

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SHIMAMURA, AKI, ARRI PRIIMAGI, JUN-ICHI MAMIYA, MOTOI KINOSHITA, TOMIKI IKEDA, and ATSUSHI SHISHIDO. "PHOTOINDUCED BENDING UPON PULSED IRRADIATION IN AZOBENZENE-CONTAINING CROSSLINKED LIQUID-CRYSTALLINE POLYMERS." Journal of Nonlinear Optical Physics & Materials 20, no. 04 (December 2011): 405–13. http://dx.doi.org/10.1142/s0218863511006200.

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We have investigated the photoresponsive behavior of homogeneously aligned low-azobenzene-concentration crosslinked liquid-crystalline polymers. We compared the thermal contraction and photocontraction of the films, and show that upon UV irradiation, they bend efficiently towards the actinic light source. The photoinduced bending is studied both under continuous-wave irradiation and irradiation with nanosecond pulses. Pulsed irradiation revealed that the photomechanical response can take place within sub-millisecond time scale, and that even a single laser pulse can cause the sample to bend.

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Neimash, V. B., A. O. Goushcha, L. L. Fedorenko, P. Ye Shepelyavyi, V. V. Strelchuk, A. S. Nikolenko, M. V. Isaiev, and A. G. Kuzmich. "Role of Laser Power, Wavelength, and Pulse Duration in Laser Assisted Tin-Induced Crystallization of Amorphous Silicon." Journal of Nanomaterials 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/1243685.

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This work describes tin-induced crystallization of amorphous silicon studied with Raman spectroscopy in thin-film structures Si-Sn-Si irradiated with pulsed laser light. We have found and analyzed dependencies of the nanocrystals’ size and concentration on the laser pulse intensity for 10 ns and 150 μm duration laser pulses at the wavelengths of 535 nm and 1070 nm. Efficient transformation of the amorphous silicon into a crystalline phase during the 10 ns time interval of the acting laser pulse in the 200 nm thickness films of the amorphous silicon was demonstrated. The results were analyzed theoretically by modeling the spatial and temporal distribution of temperature in the amorphous silicon sample within the laser spot location. Simulations confirmed importance of light absorption depth (irradiation wavelength) in formation and evolution of the temperature profile that affects the crystallization processes in irradiated structures.

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Choi, Eunmi, and Sunggyu Pyo. "Effect of Pulsed Light Irradiation on Patterning of Reduction Graphene Oxide-Graphene Oxide Interconnects for Power Devices." Coatings 11, no. 9 (August 30, 2021): 1042. http://dx.doi.org/10.3390/coatings11091042.

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Reduction graphene oxide (r-GO) lines on graphene oxide (GO) films can be prepared by a photocatalytic reduction and photothermal reduction method. A mechanism of partial GO reduction by pulsed photon energy is identified for preparing patterned rGO-GO films. The photocatalytic reduction method efficiently reduces GO at low photon energies. The successful production of a patterned rGO-GO film without damage by the photo thermal reduction method is possible when an energy density of 6.0 or 6.5 J/m2 per pulse is applied to a thin GO film (thickness: 0.45 μm). The lowest resistance obtained for a photo-reduced rGO line is 0.9 kΩ sq−1. The GO-TiO2 pattern fabricated on the 0.23 μm GO-TiO2 composite sheet through the energy density of each pulse is 5.5 J/m2 for three pulses.

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Mandal, Ronit, Xanyar Mohammadi, Artur Wiktor, Anika Singh, and Anubhav Pratap Singh. "Applications of Pulsed Light Decontamination Technology in Food Processing: An Overview." Applied Sciences 10, no. 10 (May 22, 2020): 3606. http://dx.doi.org/10.3390/app10103606.

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Consumers of the 21st century tend to be more aware and demand safe as well as nutritionally balanced food. Unfortunately, conventional thermal processing makes food safe at the cost of hampering nutritional value. The food industry is trying to develop non-thermal processes for food preservation. Pulsed light (PL) is one such emerging non-thermal food processing method that can decontaminate food products or food contact surfaces using white light. Exposure to intense light pulses (in infrared, visible, and ultraviolet (UV) regions) causes the death of microbial cells, rendering the food safe at room temperature. PL technology is an excellent and rapid method of disinfection of product surfaces and is increasingly being used for food surfaces and packaging decontamination, enabling the minimal processing of food. This paper aims to give an overview of the latest trends in pulsed light research, discuss principles of pulse generation, and review applications of various PL systems for the inactivation of microorganisms in vitro, in various food products, and on food contact surfaces. Effects of PL on food quality, challenges of the process, and its prospects are presented.

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Karaca, Emine Esra, Özlem Evren Kemer, and Dilay Özek. "Intense regulated pulse light for the meibomian gland dysfunction." European Journal of Ophthalmology 30, no. 2 (December 4, 2018): 289–92. http://dx.doi.org/10.1177/1120672118817687.

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Purpose: To assess the effect of intense regulated pulse light (E-Eye; E-Swin, France) on the treatment of meibomian gland dysfunction. Setting: Health Sciences University, Ankara Numune Training and Research Hospital, Department of Ophthalmology. Methods: A total of 26 patients underwent intense pulsed light treatment (E-Eye; E-Swin), with homogeneously sequenced five light pulses delivered to one eye at 1, 15, and 45 days following baseline evaluation. At each visit, subjective clinical parameters (ocular surface disease index questionnaire and standard patient evaluation of eye dryness questionnaire) and objective clinical parameters (Schirmer I test scores, tear break-up times, Oxford grading, lid margin abnormality score, secretion quality and expressibility degree) were recorded. The subjective and objective parameters at Days 15 and 45 were compared with baseline values. Results: Patients underwent three sessions of intense pulsed light treatment. Schirmer test and tear break-up time improved significantly from baseline to Day (D) 45 (8.53 ± 4.31 mm vs 12.6 ± 3.14 mm, 4.53 ± 1.33 sn vs 11.07 ± 2.87 sn, p = 0.003 and p < 0.001). Ocular surface disease index and standard patient evaluation of eye dryness scores improved from baseline to D15 and baseline to D45 (all with p < 0.05). All the subjects reported reduced symptoms by D45. There were no cases of adverse ocular effects. There was no significant change in Oxford grading, lid margin abnormality score, secretion quality, and expressibility degree. Conclusions: Intense regulated pulse light seems a safe treatment procedure for meibomian gland dysfunction, improving tear film quality and reducing symptoms of dry eye.

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Bai, Yeran, Delong Zhang, Lu Lan, Yimin Huang, Kerry Maize, Ali Shakouri, and Ji-Xin Cheng. "Ultrafast chemical imaging by widefield photothermal sensing of infrared absorption." Science Advances 5, no. 7 (July 2019): eaav7127. http://dx.doi.org/10.1126/sciadv.aav7127.

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Infrared (IR) imaging has become a viable tool for visualizing various chemical bonds in a specimen. The performance, however, is limited in terms of spatial resolution and imaging speed. Here, instead of measuring the loss of the IR beam, we use a pulsed visible light for high-throughput, widefield sensing of the transient photothermal effect induced by absorption of single mid-IR pulses. To extract these transient signals, we built a virtual lock-in camera synchronized to the visible probe and IR light pulses with precisely controlled delays, allowing submicrosecond temporal resolution determined by the probe pulse width. Our widefield photothermal sensing microscope enabled chemical imaging at a speed up to 1250 frames/s, with high spectral fidelity, while offering submicrometer spatial resolution. With the capability of imaging living cells and nanometer-scale polymer films, widefield photothermal microscopy opens a new way for high-throughput characterization of biological and material specimens.

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Sakamoto, Akira, Hiromi Okamoto, and Mitsuo Tasumi. "Observation of Picosecond Transient Raman Spectra by Asynchronous Fourier Transform Raman Spectroscopy." Applied Spectroscopy 52, no. 1 (January 1998): 76–81. http://dx.doi.org/10.1366/0003702981942357.

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Asynchronous Fourier transform (FT) Raman spectroscopy with 100 picosecond time resolution has been developed. A signal-processing assembly required for time-resolved and transient Raman measurements consists of a picosecond Nd:YLF laser system, a gate circuit, and a low-pass filter, and it can be attached to any conventional continuous-scan FT-Raman spectrophotometer. The principle of signal processing employed in this method is almost the same as that of asynchronous pulsed-laser-excited FT-Raman spectroscopy. This method does not require synchronization between Raman excitation by probe laser pulses and sampling by the analog-to-digital converter. Transient Raman spectra have been obtained from the first excited singlet state of three anthracene derivatives in cyclohexane solutions and photoexcited poly( p-phenylenevinylene) [(C6H4CH=CH) n] by using 351 nm light (pulse width ã 70 ps) for photoexcitation and 1053 nm light (pulse width ã 100 ps) for Raman excitation.

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Шашкин, И. С., А. Ю. Лешко, Д. Н. Николаев, В. В. Шамахов, Н. А. Рудова, К. В. Бахвалов, А. В. Лютецкий, et al. "Излучательные характеристики мощных полупроводниковых лазеров (1060 нм) с узким мезаполосковым контактом на основе асимметричных гетероструктур AlGaAs/GaAs с широким волноводом." Физика и техника полупроводников 54, no. 4 (2020): 408. http://dx.doi.org/10.21883/ftp.2020.04.49149.9333.

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Light characteristics of narrow-stripe lasers (5.5 m) based on asymmetric AlGaAs/GaAs heterostructures are studied. It was shown that the maximum optical power achieved under continuous-wave (CW) operation is limited by thermal heating and reaches 1695 mW at a current of 2350 mA at +25°C, and the maximum efficiency reaches 54.8 %. By reducing the operating temperature to -8°C, we were able to increase the maximum power to 2 W. A peak power of 2930 mW was obtained under pulsed operation (pulse width 240 ns, amplitude 4230 mA). It is shown there is a region of an “optical dip” in the power profile with a low-efficiency lasing of a train of pulses of sub-ns duration under pulsed operation.

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ABDULRAHMAN, Hayder J., and Suzan B. MOHAMMED. "DEVELOPMENT OF ULTRA-SHORT HIGH INTENSITY LASERS FOR THE VISIBLE SPECTRA RANGE." Periódico Tchê Química 17, no. 35 (July 20, 2020): 739–52. http://dx.doi.org/10.52571/ptq.v17.n35.2020.63_abdulrahman_pgs_739_752.pdf.

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Ultra-short laser pulses are particularly suitable for processing micro tools made of ultra-hard and dielectric materials. Ultra-short laser pulses provide a contact-free and precise fabrication of heat-sensitive materials such as visible spectra range. Visible spectra range has unique properties, which makes it an essential material in the tool, jewelry, and semiconductor industries. The processing of visible spectra range by ultra-short laser pulses is complex, as visible and near-infrared light is generally not absorbed. However, the intensity of ultra-short laser pulses is extremely high, so that the absorption scales nonlinearly with the intensity and, thus, visible or near-infrared light can be absorbed. The complexity also results from many partially interdependent process variables, such as the repetition rate, pulse overlap, track overlap, and scan speed. Excellent knowledge of the process is, therefore, essential for the production of micro tools. To make the laser processing accessible to a broader user field, the operator can be supported by a computer-aided design (CAD). The aim of this research was to the modeling of an ultra-short high-intensity laser for the visible spectra range in different environments of the angle of incidence, scanning speed, pulse, and track overlap. The experimental process included ultra-short pulsed laser processing of visible spectra range and surface analysis concerning modifications and ablation of the ultra-short laser. Ablation volumes were analyzed for single pulses, multi-pulses, and pockets. Pump-probe experiments reveal transient optical properties such as transmission or reflectivity. It was concluded that ultraviolet laser pulses are best suited to induce damage or modifications to visible spectra range surfaces. Additionally, shorter wavelengths have further advantages such as potentially longer Rayleigh lengths and smaller spot sizes.

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Lee, T. M., and S. E. Labyak. "Free-running rhythms and light- and dark-pulse phase response curves for diurnal Octodon degus (Rodentia)." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 273, no. 1 (July 1, 1997): R278—R286. http://dx.doi.org/10.1152/ajpregu.1997.273.1.r278.

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Only rarely have precise, short-duration light pulses been used to generate phase response curves (PRCs) in diurnal mammals as done for nocturnal mammals, and a dark-pulse PRC has never been generated for a diurnal mammal. In addition, the relationship between free-running rhythms in different light intensities and PRCs has not been explored in diurnal mammals. We examined these relationships in Octodon degus, a diurnal hystricomorph rodent. Male degus lengthened the circadian period (tau) and duration of daily activity (alpha) after an increase in light intensity from 0 (DD) to 250 lx, and tau was furthered lengthened when light intensity increased from 580 to 5,800 lx. To generate a light-pulse PRC, degus were housed in DD and exposed to 20-min light pulses (250 lx) and phase shifts recorded across the circadian day. Two different PRCs were generated in response to 20-min light pulses. The majority of animals produced significant phase delays between circadian time (CT) 0 and CT 6, phase advances between CT 13 and CT 22, and a nonsignificant response period between CT 8 and CT 13. Two animals produced a PRC devoid of significant phase delays, producing only significant phase advances between CT 17 and CT 24. To generate a dark-pulse PRC, animals were moved to LL (580 lx) and exposed to 1-h dark pulses. After dark pulses degus produced significant phase delays between CT 20 and CT 8, advances from CT 10 to CT 17, and nonsignificant responses between CT 18 and CT 20. This is the first report of a PRC to dark-pulse stimuli for a diurnal mammal. Thus light- and dark-pulse PRCs can be generated in a comparable way to those of nocturnal rodents, and we conclude that nocturnal and diurnal rodents use similar photic signals to produce somewhat different PRCs.

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Afriani, Sherli Wahyuni Dwi, Ibnu Ziad, and Suroso Suroso. "Rancang Bangun Alat Monitoring Pulsa Listrik Rumah Tinggal Berbasis Raspberry Pi Dengan Notifikasi Sms Dan E-mail." Jurasik (Jurnal Riset Sistem Informasi dan Teknik Informatika) 4, no. 1 (July 17, 2019): 89. http://dx.doi.org/10.30645/jurasik.v4i1.121.

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In this design presents the design of electric pulse monitoring devices in residential homes. This tool is designed using the Raspberry Pi as a microprosessor. In the design process, this tool uses a light sensor (Light Dependent Resistor) to read the change of lights from green to red on the electric token, Camera Pi NoIR to take pictures of electric pulses, and SIM 800 to send SMS notifications. With the programming language used in the design of this tool is Language C. In monitoring the use of electric pulses, this tool is also designed to be able to send notifications automatically when the use of electric pulses has reached the minimum limit. Notifications sent will be received in the form of sms and email by the homeowner. It is expected that this tool can provide convenience to homeowners to monitor the use of electric pulses from a distance when the house is empty.

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Kirilyuk, Andrei, Alexey V. Kimel, and Theo Rasing. "Controlling spins with light." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, no. 1951 (September 28, 2011): 3631–45. http://dx.doi.org/10.1098/rsta.2011.0168.

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The interaction of sub-picosecond laser pulses with magnetically ordered materials has developed into an extremely exciting research topic in modern magnetism. From the discovery of sub-picosecond demagnetization over a decade ago to the recent demonstration of magnetization reversal by a single 40 fs laser pulse, the manipulation of spins by ultrashort laser pulses has become a fundamentally challenging topic with a potentially high impact for future spintronics, data storage and manipulation, and quantum computation. We have recently demonstrated that one can generate ultrashort and very strong (teslas) magnetic field pulses via the so-called inverse Faraday effect. Such optically induced magnetic field pulses provide unprecedented means for the generation, manipulation and coherent control of spins on very short time scales. The basic ideas behind these so-called opto-magnetic effects will be discussed and illustrated with recent results, demonstrating the various possibilities of this new field of femto-magnetism.

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Lu, Jinsheng, Qiang Li, Cheng-Wei Qiu, Yu Hong, Pintu Ghosh, and Min Qiu. "Nanoscale Lamb wave–driven motors in nonliquid environments." Science Advances 5, no. 3 (March 2019): eaau8271. http://dx.doi.org/10.1126/sciadv.aau8271.

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Achieving light-driven motions in nonliquid environments presents formidable challenges, because microsized objects experience strong dry adhesion and intend to be stuck to contact surfaces with great tenacity. Here, in air and vacuum, we show rotary locomotion of a micrometer-sized metal plate with ~30 nm thickness, revolving around a microfiber. This motor is powered by pulsed light guided into the fiber as a coordinated consequence of an optically excited Lamb wave on the plate and favorable configuration of plate-fiber geometry. The motor, actuated by designed light pulses, crawls stepwise with subnanometer locomotion resolution. Furthermore, we can control the rotation velocity and step resolution by varying the repetition rate and pulse power, respectively. A light-actuated micromirror scanning with 0.001° resolution is then demonstrated on the basis of this motor. It offers unprecedented application potential for integrated micro-opto-electromechanical systems, outer-space all-optical precision mechanics and controls, and laser scanning for miniature lidar systems.

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Seto, Keisuke, Takayoshi Kobayashi, and Eiji Tokunaga. "Noise cancellation of white pulsed light with pulse-to-pulse observation of probe and reference pulses in spectral pump/probe measurement." Journal of Physics Communications 4, no. 12 (January 5, 2021): 125009. http://dx.doi.org/10.1088/2399-6528/abd33f.

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Zhang, Guoqing, Xiuxiu Gao, and Lina Liu. "Influences of signal processing methods on photon number resolving capability of multi-pixel photon counter." International Journal of Quantum Information 14, no. 08 (December 2016): 1650046. http://dx.doi.org/10.1142/s0219749916500465.

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Influences of signal processing methods on photon number resolving capability of multi-pixel photon counter (MPPC) were studied in this work. Results show that the photon number resolving (PNR) capability of MPPC can be greatly improved by waveform integration of the avalanche pulses of MPPC, relative to the histograms of the output pulse amplitudes. Up to 47 photon-equivalent peaks can be distinguished in the PNR spectrum with pulsed light repetition frequency of 80[Formula: see text]MHz and 5[Formula: see text]ns time gate. The analog to digital converter (ADC) in oscilloscope with more bit resolution may be beneficial for the PNR of MPPC.

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Kawazoe, Tadashi, Naoki Wada, and Motoichi Ohtsu. "Emission Spectral Control of a Silicon Light Emitting Diode Fabricated by Dressed-Photon-Phonon Assisted Annealing Using a Short Pulse Pair." Advances in Optical Technologies 2014 (July 6, 2014): 1–8. http://dx.doi.org/10.1155/2014/958327.

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We fabricated a high-efficiency infrared light emitting diode (LED) via dressed-photon-phonon (DPP) assisted annealing of a p-n homojunctioned bulk Si crystal. The center wavelength in the electroluminescence (EL) spectrum of this LED was determined by the wavelength of a CW laser used in the DPP-assisted annealing. We have proposed a novel method of controlling the EL spectral shape by additionally using a pulsed light source in order to control the number of phonons for the DPP-assisted annealing. In this method, the Si crystal is irradiated with a pair of pulses having an arrival time difference between them. The number of coherent phonons created is increased (reduced) by tuning (detuning) this time difference. A Si-LED was subjected to DPP-assisted annealing using a 1.3 μm (hν=0.94 eV) CW laser and a mode-locked pulsed laser with a pulse width of 17 fs. When the number of phonons was increased, the EL emission spectrum broadened toward the high-energy side by 200 meV or more. The broadening towards the low-energy side was reduced to 120 meV.

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Leloup, Jean-Christophe, and Albert Goldbeter. "A molecular explanation for the long-term suppression of circadian rhythms by a single light pulse." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 280, no. 4 (April 1, 2001): R1206—R1212. http://dx.doi.org/10.1152/ajpregu.2001.280.4.r1206.

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With the use of a molecular model for circadian rhythms in Drosophila based on transcriptional regulation, we show how a single, critical pulse of light can permanently suppress circadian rhythmicity, whereas a second light pulse can restore the abolished rhythm. The phenomena occur via the pulsatile induction of either protein degradation or gene expression in conditions in which a stable steady state coexists with stable circadian oscillations of the limit cycle type. The model indicates that suppression by a light pulse can only be accounted for by assuming that the biochemical effects of such a pulse much outlast its actual duration. We determine the characteristics of critical pulses suppressing the oscillations as a function of the phase at which the rhythm is perturbed. The model predicts how the amplitude and duration of the biochemical changes induced by critical pulses vary with this phase. The results provide a molecular, dynamic explanation for the long-term suppression of circadian rhythms observed in a variety of organisms in response to a single light pulse and for the subsequent restoration of the rhythms by a second light pulse.

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Puchý, Viktor, František Kováč, Ivan Petryshynets, and Ladislav Falat. "Effect of Microsecond Pulse Laser Modification on Electromagnetic Properties of Grain Oriented Silicon Steel." Materials Science Forum 891 (March 2017): 214–18. http://dx.doi.org/10.4028/www.scientific.net/msf.891.214.

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A microsecond pulsed laser beam was used to local magnetic domain modification of electrical grain oriented silicon steel. It was carried out using three different laser pulse regimes: a single pulse laser regime, a multipulse laser regime and a multipulse laser regime with modulation of laser pulses. The laser processing variables were pulse energy and and number of pulses. The samples were tested for nanohardness and coercivity before and after laser treatment. Light optical microscopy, scanning electron microscopy and magnetic force microscopy were used to observe the cross-sectional profile, surface of the samples, and magnetic domain visualization, respectively. The local laser treatment of grain oriented silicon steel surface has been studied in terms of its influence on the magnetic domains and coercivity. It was found that laser-modified samples showed coercivity improvement in comparison to the non-treated samples. The most significant improvement in coercivity was obtained in the modulated multipulse regime and negligible improvement in the single pulse laser regime. Three main effects responsible for the observed improvement were identified, namely: magnetic domain refinement, influence of number of laser pulses and shape of laser HAZ profile. The present work highlights on differences in the magnetic domain structure, microstructure of the laser modified material and basic electromagnetic and mechanical properties. In present study, the pulse laser surface processing was presented as a useful energy efficient alternative to other techniques e.g. mechanical scribing, electrical discharge scribing, plasma jet scribing, etc. The refined magnetic domains in electrosteels are responsible for the observed low coercivity, which indicates perspective application of the investigated laser modified steels in the power transformer cores with lower core losses.

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Tang, Anisia P. S., and K. S. Cheng. "Thermal X-Ray Pulses Resulting From Pulsar Glitches." International Astronomical Union Colloquium 177 (2000): 441–42. http://dx.doi.org/10.1017/s0252921100060255.

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AbstractThe non-spherical symmetric and exact thermal evolution model is used to calculate the transient thermal response to pulsar glitches. The three ways of energy release originated from glitches, namely the ‘shell’, ‘ring’ and ‘spot’ cases are compared. The ‘ring’ case is always the middle one in terms of the response time, the response duration and the intensity of the response. Taking the relativistic light bending effect and the rotational effect into consideration, the X-ray light curves resulting from the thermal response to the glitches are calculated. Only the ‘spot’ case produces modulative X-rays. Different sets of parameters result in different evolution patterns of light curves. This is thus a good method to determine the equations of state for pulsars.

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Li, Wenhai, Xiaoyi Bao, V. P. Kalosha, Liang Chen, and Ming-Jun Li. "Using Nonuniform Fiber to Generate Slow Light via SBS." Research Letters in Optics 2008 (2008): 1–4. http://dx.doi.org/10.1155/2008/253634.

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The data pulse delay based on slow light induced by stimulated Brillouin scattering (SBS) in a nonuniform dispersion decreasing fiber (DDF) is demonstrated experimentally, and the distortions of data pulses at different beat frequencies are studied. We found that a delay exceeding a pulse width can be achieved at particular beat frequency, and the DDF has larger delay versus gain slope coefficient with much better output pulse quality than single-mode fiber.

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Cudemos, E., A. Izquier, M. S. Medina-Martínez, and V. M. Gómez-López. "Effects of shading and growth phase on the microbial inactivation by pulsed light." Czech Journal of Food Sciences 31, No. 2 (April 18, 2013): 189–93. http://dx.doi.org/10.17221/145/2012-cjfs.

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Pulsed light is an emerging technology that kills microorganisms using pulses of an intense broad-spectrum light. This work aimed to determine the effect of population density and microbial growth phase on its microbicidal efficacy.  To this, Pseudomonas fluorescens cultures were grown, diluted to different population densities, flashed, plated, incubated, and enumerated, Also, cultures of P. fluorescens, Bacillus cereus, and Saccharomyces cerevisiae were taken at different growth phases, diluted to the same population density, flashed, plated, incubated, and enumerated. Microbial inactivation was lower at high densities, probably as the consequence of the shading effect, and higher at the exponential phase. This study sets the background information useful for scientists and industrial implementation. The population density and growth phase must be taken into account in the planning experiments and comparing the literature. On the industrial scale, heavily contaminated solids are not suitable for pulsed light (PL) treatment; while liquids should receive several PL flashes under the flow conditions that assure that all microorganisms receive a PL treatment, that should be also designed in function of the growth phase of the microbial contaminant.

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Journal articles on the topic 'Light pulser'

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