Tuning Characteristics of DFB Diode Laser and its Application to TDLAS Gas Sensor Design

2014 ◽  
Vol 511-512 ◽  
pp. 173-177 ◽  
Author(s):  
Rong Jun Lu ◽  
De Ming Shen ◽  
Qian Qian Du ◽  
Bao Zhen Huang ◽  
Jian Shu Shi
Keyword(s):  
Diode Lasers ◽  
Modulation Amplitude ◽  
Wavelength Modulation ◽  
Modulation Spectroscopy ◽  
Dynamic Tuning ◽  
Harmonic Components ◽  
Laser Devices ◽  
Current Tuning ◽  
Temperature Dynamic ◽  
Sweep Speed

Static and dynamic tuning characteristics of Distribute Feedback (DFB) diode lasers are investigated with practical laser devices. These characteristics are the basic guidelines for practical TDLAS sensors design. Static tuning characteristics help to select suitable diode lasers from limited available laser devices with specific wavelength and to set an appropriate working current and temperature. Dynamic tuning characteristics decide the sweep speed of current slope in both direct absorb Spectroscopy (DAS) and wavelength modulation Spectroscopy (WMS). Because of nonlinearity in the relation between wavelength and tuning current, the measured spectral line position should be corrected by the dynamic characteristics. For WMS, current tuning efficient and IM/AM (Intense modulation/Amplitude modulation) differential phase could be utilized to optimize laser modulation and harmonic components demodulation.

Heterogeneous Neuronal Responses to Frequency-Modulated Tones in the Primary Auditory Cortex of Awake Cats

2008 ◽  
Vol 100 (3) ◽  
pp. 1622-1634 ◽  
Author(s):  
Ling Qin ◽  
JingYu Wang ◽  
Yu Sato
Keyword(s):  
Receptive Field ◽  
Auditory Cortex ◽  
Response Pattern ◽  
Primary Auditory Cortex ◽  
Neuronal Responses ◽  
Discrete Response ◽  
A Cell ◽  
Pure Tones ◽  
Awake Cats ◽  
Sweep Speed

Previous studies in anesthetized animals reported that the primary auditory cortex (A1) showed homogenous phasic responses to FM tones, namely a transient response to a particular instantaneous frequency when FM sweeps traversed a neuron's tone-evoked receptive field (TRF). Here, in awake cats, we report that A1 cells exhibit heterogeneous FM responses, consisting of three patterns. The first is continuous firing when a slow FM sweep traverses the receptive field of a cell with a sustained tonal response. The duration and amplitude of FM response decrease with increasing sweep speed. The second pattern is transient firing corresponding to the cell's phasic tonal response. This response could be evoked only by a fast FM sweep through the cell's TRF, suggesting a preference for fast FM. The third pattern was associated with the off response to pure tones and was composed of several discrete response peaks during slow FM stimulus. These peaks were not predictable from the cell's tonal response but reliably reflected the time when FM swept across specific frequencies. Our A1 samples often exhibited a complex response pattern, combining two or three of the basic patterns above, resulting in a heterogeneous response population. The diversity of FM responses suggests that A1 use multiple mechanisms to fully represent the whole range of FM parameters, including frequency extent, sweep speed, and direction.

A Study of Melting and Resolidification of Silicon-on-Insulator Structures Formed by Lateral Epitaxy

1985 ◽  
Vol 53 ◽  
Author(s):  
D A Williams ◽  
R A Mcmahon ◽  
D G Hasko ◽  
H Ahmed ◽  
G F Hopper ◽  
...  
Keyword(s):  
Cross Sections ◽  
Silicon On Insulator ◽  
One Dimensional ◽  
Wide Range ◽  
Background Temperature ◽  
Lateral Epitaxy ◽  
Polycrystalline Silicon Films ◽  
Beam Technique ◽  
Sweep Speed

ABSTRACTThe formation of silicon-on-insulator structures, by recrystallising polycrystalline silicon films with a dual electron beam technique, has been studied over a wide range of conditions. The quality of the layers has been assessed by examining cross-sections in the SEM and optical microscopy of the surface after a Secco etch. The range of line powers which gives device-worthy single crystal material becomes greater as the sweep speed increases and as the background temperature is reduced. The extent of melting into the substrate in the seed windows and below the isolating oxide was determined from the movement of an arsenic implant. The experimental results are compared to the predictions from a one dimensional model for the heat flow.

Foveal Flicker Fusion Using a Moving Stimulus

1965 ◽  
Vol 21 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Grant D. Miller ◽  
Duane A. Anderson ◽  
Ernst Simonson
Keyword(s):  
Linear Increase ◽  
Multiple Correlation ◽  
Experimental Conditions ◽  
Flicker Fusion Frequency ◽  
Stimulus Velocity ◽  
Stationary Stimulus ◽  
Moving Stimulus ◽  
The Relationship ◽  
Flicker Fusion ◽  
Sweep Speed

The relationship between stimulus velocity and the critical-flicker-fusion frequency (CFF) of an intermittent visual stimulus was investigated by modulating the sweep-speed and intensity of an oscilloscope beam. When Ss fixated upon a stationary point, CFF showed an approximately linear increase as a function of velocity. Velocity did not, however, influence CFF when S fixated on the moving stimulus. The multiple correlation (.68) between CFF determinations obtained with a stationary stimulus vs those obtained with several different velocities implies that the same mechanisms which determined CFF under the former condition were also operative in the latter. The trend of the bivariate correlations between the average CFF values for isolated pairs of experimental conditions suggests that an additional factor, possibly spatial acuity, may have become progressively dominant as velocities exceeded 1.08°/sec.

Note: X-ray streak camera sweep speed calibration

2010 ◽  
Vol 81 (5) ◽  
pp. 056108 ◽  
Author(s):  
Tuo Zhu ◽  
Jia-Min Yang ◽  
Bo Deng ◽  
Dong Yang ◽  
Xiao-an He ◽  
...  
Keyword(s):  
Streak Camera ◽  
X Ray ◽  
Sweep Speed

Inadvertent placement of a pulmonary artery catheter in the coronary sinus: is it time to increase our sweep speed?

2011 ◽  
Vol 23 (6) ◽  
pp. 492-497 ◽  
Author(s):  
Hamdy Awad ◽  
Shéleste V. Ladson ◽  
Jamie R. Wingate ◽  
Mohamed Abd Eldayem ◽  
Keri J. Hudec ◽  
...  
Keyword(s):  
Pulmonary Artery ◽  
Pulmonary Artery Catheter ◽  
Coronary Sinus ◽  
Sweep Speed

Electrochemical Behavior and Convoluted Voltammetry of Carbon Nanotubes Modified with Anthraquinone

2017 ◽  
Vol 20 (1) ◽  
pp. 025-030 ◽  
Author(s):  
Mohamed A. Ghanem ◽  
Ibrahim S. El-Hallag ◽  
Abdullah M. Al-Mayouf
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Reaction ◽  
Rotating Disk ◽  
Rotating Disk Electrode ◽  
Disk Electrode ◽  
Chemically Modified ◽  
Minor Contribution ◽  
Rotating Disk Electrode Voltammetry ◽  
Constant State ◽  
Sweep Speed

The validity of convolution voltammetry for determination accurate values of diffusion coefficient (D) and electrons number (n) consumed in electrochemical reaction has been explained by applying the technique to a carbon nanotubes chemically modified using func-tional groups of anthraquinone(AQ). The analysis with macrodisk electrode was facilitated due to the presence of minor contribution of nonfaradaic current, so moderate values of sweep speed can be used without subtraction of residual current to quantify the diffusivity of electro-active species.The values of D and nCb were determined simultaneously and demonstrated using convoluted procedure. The ob-tained results indicate that the convolution voltammetry provides advantages over constant state methods (plateau) such as micro-disk electrode voltammetry and rotating disk electrode voltammetry, as it is not limited by the method of diffusion (planar or radial), which remove the limitations of solvent viscosity, geometry of electrode, and voltammetric sweep speed.

Sweep Speed, Time of Exposure, and Perceptual Lag

1980 ◽  
Vol 105 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Michael D. Doran ◽  
Daniel O. Bowman ◽  
James D. Pietrangeli
Keyword(s):  
Sweep Speed

scholarly journals Conductance Quantization Behavior in Pt/SiN/TaN RRAM Device for Multilevel Cell

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1918
Author(s):  
Jongmin Park ◽  
Seungwook Lee ◽  
Kisong Lee ◽  
Sungjun Kim
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Pulse Train ◽  
Conduction Mechanism ◽  
Differential Resistance ◽  
X Ray ◽  
Conductance Quantization ◽  
Negative Differential Resistance Effect ◽  
Memristor Device ◽  
Sweep Speed

In this work, we fabricated a Pt/SiN/TaN memristor device and characterized its resistive switching by controlling the compliance current and switching polarity. The chemical and material properties of SiN and TaN were investigated by X-ray photoelectron spectroscopy. Compared with the case of a high compliance current (5 mA), the resistive switching was more gradual in the set and reset processes when a low compliance current (1 mA) was applied by DC sweep and pulse train. In particular, low-power resistive switching was demonstrated in the first reset process, and was achieved by employing the negative differential resistance effect. Furthermore, conductance quantization was observed in the reset process upon decreasing the DC sweep speed. These results have the potential for multilevel cell (MLC) operation. Additionally, the conduction mechanism of the memristor device was investigated by I-V fitting.

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