The Experts below are selected from a list of 56526 Experts worldwide ranked by ideXlab platform
Rajendra Singh - One of the best experts on this subject based on the ideXlab platform.
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effect of rapid thermal annealing on barrier height and 1 f noise of ni gan schottky barrier diodes
Applied Physics Letters, 2015Co-Authors: Ashutosh Kumar, V Kumar, Michael Latzel, Silke Christiansen, Rajendra SinghAbstract:Current-voltage (as a function of temperature), capacitance-voltage, and 1/f noise characteristics of Ni/GaN Schottky barrier diodes (SBDs) as function of rapid thermal annealing (RTA) are studied. It is found that RTA treatments of SBDs at 450 °C for 60 s resulted in a significant improvement of ideality factor and Schottky barrier height: the ideality factor decreased from 1.79 to 1.12 and the barrier height increased from 0.94 to 1.13 eV. The Spectral Power Density of current fluctuations in the diode subjected to RTA at 450 °C is found to be two orders of magnitude lower as compared to the as-deposited diode. Improved diode characteristics and decreased 1/f noise in RTA treated (450 °C/60 s) diode are attributed to reduced level of barrier inhomogeneities at the metal-semiconductor interface and explained within the framework of the spatial inhomogeneity model.
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temperature dependence of 1 f noise in ni n gan schottky barrier diode
Journal of Applied Physics, 2012Co-Authors: Ashutosh Kumar, K Asokan, V Kumar, Rajendra SinghAbstract:1/f noise measurements were performed on Ni/n-GaN Schottky barrier diode under forward bias over a wide temperature range from 80 to 300 K. The noise spectra exhibited frequency dependence proportional to 1/f′ with γ varying between 0.8 and 1.1 down to 1 Hz. The Spectral Power Density of current fluctuations, SI, was found to decrease with increase in temperature. Current-voltage (I-V) characteristics of the diodes have been measured, and metal-semiconductor interface was found to be spatially inhomogeneous in the temperature range 80–300 K. The decrease in 1/f noise with increase in temperature is explained within the framework of spatial inhomogeneities model.
Daniel P. Kammen - One of the best experts on this subject based on the ideXlab platform.
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pimavanserin tartrate a 5 ht2a receptor inverse agonist increases slow wave sleep as measured by polysomnography in healthy adult volunteers
Sleep Medicine, 2011Co-Authors: Sonia Ancoliisrael, Kimberly E Vanover, David M. Weiner, Robert E. Davis, Daniel P. KammenAbstract:Abstract Objective Determine the effects of pimavanserin tartrate [ACP-103; N -(4-flurophenylmethyl)- N -(1-methylpiperidin-4-yl)- N ′-(4-(2-methylpropyloxy)phenylmethyl)carbamide], a selective serotonin 5-HT 2A receptor inverse agonist, on slow wave sleep (SWS), other sleep parameters, and attention/vigilance. Methods Forty-five healthy adults were randomized to pimavanserin (1, 2.5, 5, or 20mg) or placebo in a double-blind fashion ( n =9/group). Pimavanserin or placebo was administered once daily in the morning for 13 consecutive days. The effects of pimavanserin were measured after the first dose and again after 13days. Sleep parameters were measured by polysomnography. Effects on attention/vigilance were measured by a continuous performance task. Results Compared to placebo, pimavanserin significantly increased SWS following single and multiple dose administration. Pimavanserin also decreased number of awakenings. PSG variables not affected by pimavanserin included sleep period time, total sleep time, sleep onset latency, number of stage shifts, total time awake, early morning wake, and microarousal index. Changes in sleep architecture parameters, sleep profile parameters, and Spectral Power Density parameters were consistent with a selective increase in SWS. Pimavanserin did not adversely affect performance on the continuous performance test measured in the evening before or morning after polysomnography. Conclusions These data suggest that pimavanserin selectively increases slow wave sleep and decreases awakenings, an effect that does not diminish with repeated administration.
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pimavanserin tartrate a 5 ht2a receptor inverse agonist increases slow wave sleep as measured by polysomnography in healthy adult volunteers
Sleep Medicine, 2011Co-Authors: Sonia Ancoliisrael, Kimberly E Vanover, David M. Weiner, Robert E. Davis, Daniel P. KammenAbstract:Abstract Objective Determine the effects of pimavanserin tartrate [ACP-103; N -(4-flurophenylmethyl)- N -(1-methylpiperidin-4-yl)- N ′-(4-(2-methylpropyloxy)phenylmethyl)carbamide], a selective serotonin 5-HT 2A receptor inverse agonist, on slow wave sleep (SWS), other sleep parameters, and attention/vigilance. Methods Forty-five healthy adults were randomized to pimavanserin (1, 2.5, 5, or 20mg) or placebo in a double-blind fashion ( n =9/group). Pimavanserin or placebo was administered once daily in the morning for 13 consecutive days. The effects of pimavanserin were measured after the first dose and again after 13days. Sleep parameters were measured by polysomnography. Effects on attention/vigilance were measured by a continuous performance task. Results Compared to placebo, pimavanserin significantly increased SWS following single and multiple dose administration. Pimavanserin also decreased number of awakenings. PSG variables not affected by pimavanserin included sleep period time, total sleep time, sleep onset latency, number of stage shifts, total time awake, early morning wake, and microarousal index. Changes in sleep architecture parameters, sleep profile parameters, and Spectral Power Density parameters were consistent with a selective increase in SWS. Pimavanserin did not adversely affect performance on the continuous performance test measured in the evening before or morning after polysomnography. Conclusions These data suggest that pimavanserin selectively increases slow wave sleep and decreases awakenings, an effect that does not diminish with repeated administration.
Pierre-alain Champert - One of the best experts on this subject based on the ideXlab platform.
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High Spectral Power Density supercontinuum generation in a nonlinear fiber amplifier
Optics express, 2007Co-Authors: Paul-henri Pioger, Vincent Couderc, Philippe Leproux, Pierre-alain ChampertAbstract:We present an experimental study on supercontinuum generation with high Spectral Power Density by using a commercial nonlinear fiber amplifier. This new approach consists in the simultaneous combination of the amplification of a pulsed seed signal at 1.06 µm and its peak-Power-induced Spectral broadening as the optical pulse propagates along the amplifying fiber. A 750-nm broadening from 1 µm to 1.75 µm with tunable Spectral Power Density according to the amplifier gain level is obtained. Spectral Power Density in excess of 3 mW/nm is demonstrated.
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1 5 2 0 spl mu m multiwatt continuum generation in dispersion shifted fiber by use of high Power continuous wave fiber source
IEEE Photonics Technology Letters, 2004Co-Authors: Pierre-alain Champert, Vincent Couderc, Alain BarthelemyAbstract:We demonstrated the generation of multiwatt single-mode infrared continuum by using highly nonlinear dispersion-shifted optical fiber pumped by a continuous-wave erbium fiber source. A smooth 1000-nm at -20-dB-wide continuum is demonstrated with a remarkable 450-nm full-width at half-maximum bandwidth. A maximum Spectral Power Density of 4.5 mW/nm is obtained.
Ashutosh Kumar - One of the best experts on this subject based on the ideXlab platform.
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effect of rapid thermal annealing on barrier height and 1 f noise of ni gan schottky barrier diodes
Applied Physics Letters, 2015Co-Authors: Ashutosh Kumar, V Kumar, Michael Latzel, Silke Christiansen, Rajendra SinghAbstract:Current-voltage (as a function of temperature), capacitance-voltage, and 1/f noise characteristics of Ni/GaN Schottky barrier diodes (SBDs) as function of rapid thermal annealing (RTA) are studied. It is found that RTA treatments of SBDs at 450 °C for 60 s resulted in a significant improvement of ideality factor and Schottky barrier height: the ideality factor decreased from 1.79 to 1.12 and the barrier height increased from 0.94 to 1.13 eV. The Spectral Power Density of current fluctuations in the diode subjected to RTA at 450 °C is found to be two orders of magnitude lower as compared to the as-deposited diode. Improved diode characteristics and decreased 1/f noise in RTA treated (450 °C/60 s) diode are attributed to reduced level of barrier inhomogeneities at the metal-semiconductor interface and explained within the framework of the spatial inhomogeneity model.
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temperature dependence of 1 f noise in ni n gan schottky barrier diode
Journal of Applied Physics, 2012Co-Authors: Ashutosh Kumar, K Asokan, V Kumar, Rajendra SinghAbstract:1/f noise measurements were performed on Ni/n-GaN Schottky barrier diode under forward bias over a wide temperature range from 80 to 300 K. The noise spectra exhibited frequency dependence proportional to 1/f′ with γ varying between 0.8 and 1.1 down to 1 Hz. The Spectral Power Density of current fluctuations, SI, was found to decrease with increase in temperature. Current-voltage (I-V) characteristics of the diodes have been measured, and metal-semiconductor interface was found to be spatially inhomogeneous in the temperature range 80–300 K. The decrease in 1/f noise with increase in temperature is explained within the framework of spatial inhomogeneities model.
Steven Ness - One of the best experts on this subject based on the ideXlab platform.
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visible light optical coherence tomography angiography vis octa facilitates local microvascular oximetry in the human retina
Biomedical Optics Express, 2020Co-Authors: Weiye Song, Wenjun Shao, Rongrong Liu, Manishi Desai, Steven NessAbstract:We report herein the first visible light optical coherence tomography angiography (vis-OCTA) for human retinal imaging. Compared to the existing vis-OCT systems, we devised a spectrometer with a narrower bandwidth to increase the Spectral Power Density for OCTA imaging, while retaining the major Spectral contrast in the blood. We achieved a 100 kHz A-line rate, the fastest acquisition speed reported so far for human retinal vis-OCT. We rigorously optimized the imaging protocol such that a single acquisition took < 6 seconds with a field of view (FOV) of 3×7.8 mm2. The angiography enables accurate localization of microvasculature down to the capillary level and thus enables oximetry at vessels < 100 µm in diameter. We demonstrated microvascular hemoglobin oxygen saturation (sO2) at the feeding and draining vessels at the perifoveal region. The longitudinal repeatability was assessed by < 5% coefficient of variation (CV). The unique capabilities of our vis-OCTA system may allow studies on the role of microvascular oxygen in various retinal pathologies.
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visible light optical coherence tomography angiography vis octa and local microvascular retinal oximetry in human retina
bioRxiv, 2020Co-Authors: Weiye Song, Wenjun Shao, Rongrong Liu, Manishi Desai, Steven NessAbstract:We report herein the first visible light optical coherence tomography angiography (vis-OCTA) for human retinal imaging. Compared to the existing vis-OCT systems, we devised a spectrometer with a narrower bandwidth to increase the Spectral Power Density for OCTA imaging, while retaining the major Spectral contrast in the blood. We achieved a 100 kHz A-line rate, the fastest acquisition speed reported so far for human retinal vis-OCT. We rigorously optimized the imaging protocol such that a single acquisition takes <6 seconds with a field of view (FOV) of 3x7.8 mm2. The angiography enables accurate localization of microvasculature down to the capillary level and thus enables oximetry at vessels < 100 m in diameter. We demonstrated microvascular hemoglobin oxygen saturation (sO2) at the feeding and draining vessels at the perifoveal region. The longitudinal repeatability was assessed by <5% coefficient of variation (CV). The unique capabilities of our vis-OCTA system may allow studies on the role of microvascular oxygen in various retinal pathologies.
