scholarly journals SPECTRAL RESPONSE PREDICTION BASED ON NONLINEAR STEADY-STATE VIBRATION THEORY INCLUDING TORSIONAL MOTION

2012 ◽  
Vol 77 (674) ◽  
pp. 555-564
Author(s):  
Yoshihiro YAMAZAKI ◽  
Kazuhiko KASAI
Keyword(s):  
Steady State ◽  
Spectral Response ◽  
Response Prediction ◽  
Torsional Motion ◽  
Vibration Theory

Spectral response of steady-state photoluminescence from GaAs1-xPx layers grown on a SiGe/Si system

2017 ◽  
Vol 111 (12) ◽  
pp. 121103 ◽  
Author(s):  
Li Wang ◽  
Michael E. Pollard ◽  
Mattias Klaus Juhl ◽  
Brianna Conrad ◽  
Anastasia Soeriyadi ◽  
...  
Keyword(s):  
Steady State ◽  
Spectral Response

The Study of Space Charge Effects by Spectral Response, Steady State Charge Collection and Transient Photocurrents in Thick a-Si:H Pin-Diodes

1996 ◽  
Vol 420 ◽  
Author(s):  
J.-H. Zollondz ◽  
R. Brüggemann ◽  
S. Reynolds ◽  
C. Main ◽  
W. Gao ◽  
...  
Keyword(s):  
Steady State ◽  
Defect Density ◽  
Collection Efficiency ◽  
Spectral Response ◽  
Photon Flux ◽  
Charge Collection ◽  
Internal Variables ◽  
Pin Diodes ◽  
Charge Effects ◽  
Amplification Ratio

AbstractCharge collection, transient photocurrents and collection efficiency under additional bias illumination were used to characterize 3–4 micron thick a-Si:H pin-diodes. The wavelength dependent decrease or increase in the spectral response, depending on the bias flux and absorption depth, is related to the distribution of the electric field, recombination and majority carrier diffusion. At higher photon flux an overshoot in the transient photocurrent after switch-on of steady illumination indicates the time scale for the changes in internal variables. Collection efficiencies under large bias monochromatic photon flux well in excess of the maximum value of 100 % for probe beam generated carriers are observed with a large amplification ratio. These efficiencies sensitively depend both on the applied voltage and the defect density. Numerical modelling reveals the influence of internal variables on the transient and steady state photocurrents under the different illumination conditions.

scholarly journals The Shock Response Prediction of Spacecraft Structure Based on Hybrid FE-SEA Method

2021 ◽  
Vol 11 (18) ◽  
pp. 8490
Author(s):  
Xiong Wang ◽  
Wei Liu ◽  
Xiao Li ◽  
Yi Sun
Keyword(s):  
Steady State ◽  
Frequency Conversion ◽  
Response Spectrum ◽  
Response Prediction ◽  
Test System ◽  
State Theory ◽  
The Novel ◽  
Time Frequency ◽  
Shock Response ◽  
Novel Method

An improved method based on the Hybrid Finite Element-Statistical Energy Analysis (FE-SEA) method and quasi-steady state theory is proposed to predict the response of spacecraft structure during the process of pyrotechnics separation. Firstly, the amplitude–frequency value of shock load is obtained by using time-frequency conversion technology. Then, according to the frequency response characteristics of each part of the spacecraft structure, a more accurate hybrid FE-SEA model is established. The piecewise loading method is used to predict the response of the hybrid model. Finally, the time domain response results are reconstructed, and the shock response spectrum (SRS) is calculated. Based on the test system of simulating pyroshock, the shock experiment of spacecraft structure is conducted. The high frequency and high velocity character of pyroshock could be effectively simulated, and an accurate shock force function could be obtained through the experiment. This indicates that the numerical results are in line with the ones of the experiment. The SRS obtained from experiments and calculations have similar trends and amplitudes. This conclusion verifies the rationality and sufficient accuracy of the novel method in this paper. The novel method presented in this paper greatly improves the computational efficiency. At the same time, it provides theoretical guidance for shock response prediction of spacecraft structure by steady-state methods.

Opto-Electrical Modeling of CMOS Buried Quad Junction Photodetector

2014 ◽  
Vol 605 ◽  
pp. 470-473 ◽  
Author(s):  
S. Feruglio ◽  
Thierry Courcier ◽  
A. Karami ◽  
A. Alexandre-Gauthier ◽  
O. Romain ◽  
...  
Keyword(s):  
Spectral Response ◽  
Intrinsic Noise ◽  
Response Prediction ◽  
Cmos Technology ◽  
Device Structure ◽  
Double Junction ◽  
The Mean ◽  
Dark Currents ◽  
Analytical Expressions ◽  
Good Agreement

A Buried Quad Junction (BQJ) PhotoDetector (PD), composed of four vertically-stacked p-n junctions, has recently been implemented and fabricated in CMOS technology. The detector, providing four different spectral responses, has higher spectral discriminating ability than both conventional Buried Double Junction (BDJ) and Buried Triple Junction (BTJ) detectors. For rapid system design integrating of the BQJ PD, we propose a BQJ SPICE-like model based on the physical properties of the device structure. The analytical expressions of the four BQJ photocurrents have been developed. Dark currents as well as intrinsic noise can also be evaluated by computations. Results have been compared with both TCAD simulations and measurements. Our model shows a good agreement with measurements and the mean relative error on spectral response prediction is between 6 % and 17 % in function of the observed junction.

Novel device for implementation of WDM in the visible spectrum

2012 ◽  
Vol 1438 ◽  
Author(s):  
P. Louro ◽  
M. Vieira ◽  
M. A. Vieira ◽  
V. Silva ◽  
A. Fantoni
Keyword(s):  
Steady State ◽  
Spectral Response ◽  
Visible Spectrum ◽  
Visible Range ◽  
Light Conditions ◽  
Optical Signals ◽  
Novel Device ◽  
Insight Into ◽  
Selective Behavior

ABSTRACTIn this paper we report the use of a device based on two multilayered a-SiC:H/a-Si:H stacked heterostructures to photodetect and demultiplex optical signals of the visible spectrum. Both heterostructures were optimized for the detection of short and long wavelengths within the visible range. The optoelectronic characterization of the device includes spectral response measurements under reverse bias and using different optical steady state light conditions to soak the device. Results show that the device photocurrent signal measured using appropriate steady state optical bias, allows the separate detection of the input transmitted signals which enables the demultiplexing task. A numerical simulation, gives insight into the transduction mechanism to explain the device wavelength selective behavior.

Steady State Response Prediction of General Linear Structures Coupled by Local Nonlinear Elements

1998 ◽  
Vol 120 (3) ◽  
pp. 648-649
Author(s):  
K. Q. Xu ◽  
H. J. Rice
Keyword(s):  
Steady State ◽  
Time Domain ◽  
Response Prediction ◽  
Direct Application ◽  
Time Domain Method ◽  
General Linear ◽  
Short Paper ◽  
Steady State Response ◽  
Linear Structures ◽  
State Response

This short paper is concerned with a direct application of the techniques developed by the authors in two previous publications. It is considered as a “booster” to the existing alternating frequency/time domain method which already has many important advantages over most other methods.

Transient Versus Steady State Measurements on the Transport Properties of a-SI:H Films

1992 ◽  
Vol 258 ◽  
Author(s):  
M. Vieira ◽  
R. Martins ◽  
E. Fortunato ◽  
F. Soares ◽  
L. Guimarães
Keyword(s):  
Steady State ◽  
Transport Properties ◽  
Spectral Response ◽  
Incident Light ◽  
Monochromatic Light ◽  
Optical Excitation ◽  
Effective Lifetime ◽  
Photo Effect ◽  
Transient Measurement

ABSTRACTTransient and steady-state measurements of the ambipolar diffusion length (L*) in undoped a-Si:H films have been carried out through Flying Spot Technique (FST) and Spectral Photovoltage Technique (SPT) using either Schottky or pin structures. The FST is based on the photovoltage response of a monochromatic light that moves with a constant velocity in the interface direction, while in SPT the optical excitation is achieved by changing the absorption coefficient of the incident light and so, the light depth penetration. In FST the additional photo-effect due to the light spot movement allows to infer separately L* and the effective lifetime, (τ*) while in SPT the curve shape of the spectral response allows to estimate the interface behavior and L*. The obtained results reveal that the transient measurement is useful for determining the transport properties of the bulk while the steady technique seems to be more useful to infer the role of the interface on device performances. Limitations of the above techniques will also be reported.

Coupled Lateral-Torsional Vibration of a Gear-Pair System Supported by a Squeeze Film Damper

1993 ◽  
Author(s):  
Chin-Shong Chen ◽  
S. Natsiavas ◽  
Harold D. Nelson
Keyword(s):  
Steady State ◽  
Coupled System ◽  
Squeeze Film ◽  
Gear Pair ◽  
Torsional Motion ◽  
Squeeze Film Damper ◽  
Gear Mesh ◽  
Mass Unbalance ◽  
Steady State Responses ◽  
State Responses

Abstract This paper investigates the coupled lateral-torsional vibration of a gear-pair system supported by a cavitated squeeze film damper (SFD). Both steady state and transient dynamic characteristics of the system are analyzed. In order to gain insight into the dynamics of the system, the free vibration frequencies and modes of the linearized system are first determined. Then, the response of the nonlinear system is examined under mass unbalance and torque excitation. The trigonometric collocation method (TCM) is employed to obtain periodic steady-state responses. Direct integration is also used in order to verify TCM and capture transient response. A comparison of the steady state responses obtained with the present model by first considering only the lateral vibration and then including torsional effects demonstrates the need to include the coupling between lateral and torsional motion. Then, the effect of parameters such as gear mesh stiffness and damping, clearance-to-diameter ratio of the SFD and gear mass unbalance on the steady state response is also presented. It is found that the mass unbalance excites not only lateral-dominated modes of the coupled system but also torsional-dominated modes. Further numerical results show that the modes of the coupled system which are dominated by lateral motion can be attenuated by using a SFD, while the modes dominated by torsional motion can be substantially suppressed by gear mesh damping. Finally, the presence of multiple solutions and complex response is predicted in some frequency ranges.

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