Light filtering devices using background wavelength processing techniques

2012 ◽  
Vol 1426 ◽  
pp. 175-180
Author(s):  
M. A. Vieira ◽  
M. Vieira ◽  
P. Louro ◽  
V. Silva ◽  
A. S. Garção
Keyword(s):  
Steady State ◽  
Physical Model ◽  
Spectral Sensitivity ◽  
Wavelength Range ◽  
Communication Channels ◽  
Light Penetration ◽  
Signal Attenuation ◽  
Pass Filter ◽  
Processing Techniques ◽  
Penetration Depths

ABSTRACTThis paper reports on light filtering devices based on a-SiC:H tandem pi´n/pin heterostructures. The spectral sensitivity is analyzed. Steady state optical bias with different wavelengths, are applied from each front and back sides and the photocurrent is measured. Results show that it is possible to control the sensitivity of the device and to tune a specific wavelength range by combining radiations with complementary light penetration depths. The transfer characteristics effects due to changes in the front and back optical bias wavelength are discussed.Input red, green and blue pulsed communication channels are transmitted together, each one in a specific bit sequence and the multiplex signal is analyzed. By superimposing appropriate background and depending on the channel/background wavelength combinations, the device behaves as a long- or a short- pass filter, producing signal attenuation, or as an amplifier, producing signal gain. A physical model is presented to support the filter properties of the device.

Light-Evoked Electrical Potentials from the Eye and Optic Nerve of Strombus: Response Waveform and Spectral Sensitivity

1974 ◽  
Vol 60 (2) ◽  
pp. 383-396
Author(s):  
HOWARD L. GILLARY
Keyword(s):  
Steady State ◽  
Optic Nerve ◽  
Spectral Sensitivity ◽  
Visual Pigment ◽  
Synaptic Inhibition ◽  
Nerve Fibres ◽  
Electrical Potentials ◽  
Peak Absorption ◽  
Negative Erg ◽  
Sensitivity Studies

1. The cornea-negative ERG of the eye of Strombus exhibited two distinct ‘on’ peaks, a steady state during sustained illumination, and small rhythmic oscillations following the cessation of stimulation. 2. In certain afferent optic nerve fibres, illumination evoked phasic and tonic ‘on’ responses; others, whose activity was inhibited by light, responded with repetitive ‘off’ bursts which tended to occur in phase with the rhythmic ERG oscillations. 3. Spectral sensitivity studies indicate the presence of a single visual pigment with a peak absorption of about 485 nm. 4. The effects on the response of temperature and stimulus intensity and frequency were also examined. 5. The results indicate photo-excitation and synaptic inhibition of the receptors, and excitatory coupling between them.

Penetration by Long Rods

1992 ◽  
Author(s):  
Peter P. Gillis ◽  
Joel W. House ◽  
S. E. Jones
Keyword(s):  
Steady State ◽  
Recent Result ◽  
Substantial Improvement ◽  
Hole Diameter ◽  
Computational Method ◽  
Predictive Capability ◽  
Steady State Analysis ◽  
Post Test ◽  
Post Impact ◽  
Penetration Depths

Abstract This paper relates to the penetration of large, massive targets by long rods where target penetration is accompanied by rod erosion. A principal criticism of previous analyses of this problem by the present authors was the use of post test measurements to furnish input information for calculations. Thus, the analyses had no truly predictive capability. In particular, the profile hole diameter of the experimental target crater was previously employed as a measure of mushroom strain at the penetrator tip. Because this strain value has a significant effect on calculated penetration depths, it is very important to be able to predict it rather than measure it. In this paper a recent result from the analysis of the initial transient penetration phase is used to estimate mushroom strain. This result is incorporated into the previous steady-state analysis to make it predictive. This new theory is the basis for calculations that are compared with previously published experimental results. The degree of agreement is really quite good for a procedure in which there are no adjustable parameters. In any case, the new computational method is certainly a substantial improvement over the previous reliance on post impact information.

Biomimetische Photosysteme zur sakrifiziellen Wasserreduktion / Novel Biomimetic Systems for Visible Light Induced Water Reduction

1993 ◽  
Vol 48 (3) ◽  
pp. 369-386 ◽  
Author(s):  
Stefan Boßmann ◽  
Heinz Dürr ◽  
Eduard Mayer
Keyword(s):  
Steady State ◽  
Visible Light ◽  
Physical Model ◽  
Photochemical Reaction ◽  
Model Systems ◽  
Luminescence Spectroscopy ◽  
Quantum Yields ◽  
Biomimetic Systems ◽  
State Luminescence

Novel microheterogeneous systems for the direct photoreduction of water using visible light in analogy to the photochemical reaction center of Rhodopseudomonas viridis are described in detail. These physical model systems for photosynthesis feature the recently synthesized bisheteroleptic metal complexes [Ru(bpy)2(PP)]Cl2, [Ru(bpy)2(PPB)]Cl2, [Ru(bpy)2(PPB-pCl)]Cl2 and [Ru(bpy)3]Cl2, adsorbed on a negatively charged SiO2—TiO2-colloid, the zwitterionic electron relay PVS and a long-term stable and highly efficient TiO2—Pt-“antenna” catalyst as well as TEOA as sacrificial electron donor.Evidence for the directed absorption of the sensitizers on the SiO2—TiO2-colloid is taken from UV-VIS-measurements, steady-state luminescence-spectroscopy and the quantum yields for PVS-reduction.The hydrogen production in the presence of the SiO2—TiO2-colloid is clearly enhanced and proofs the validity of the underlying concept of physical model systems for photosynthesis.

scholarly journals ɤ-TiAl Alloy: Tensile Creep Deformation Behaviour and Creep Life at 832 °C

2021 ◽  
Author(s):  
Mainak Saha
Keyword(s):  
Steady State ◽  
Creep Deformation ◽  
Original Work ◽  
Single Phase ◽  
Tial Alloy ◽  
Deformation Behaviour ◽  
Steady State Creep ◽  
Tensile Creep ◽  
Creep Life ◽  
Processing Techniques

Creep deformation in single phase ɤ-TiAl alloy manufactured using different processing techniques has been an extensively studied topic since the late 1970s. The present work revisits the original work on understanding the tensile creep deformation behaviour of wrought single-phase ɤ-TiAl alloy by Hayes and Martin [1] and is aimed to develop an understanding of steady state creep. Besides, it is also aimed to investigate the creep life for stress levels of 69.4 and 103.4 MPa at 832 ⁰C using Monkman-Grant [2] approach.

A Spatially Resolved Physical Model for Dynamic Modeling of a Novel Hybrid Reformer-Electrolyzer-Purifier (REP) for Production of Hydrogen

2017 ◽  
Author(s):  
Derek McVay ◽  
Li Zhao ◽  
Jack Brouwer ◽  
Fred Jahnke ◽  
Matt Lambrech
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Steady State ◽  
Fuel Cell ◽  
Physical Model ◽  
Physical Models ◽  
Co2 Removal ◽  
Molten Carbonate ◽  
Spatially Resolved ◽  
Production Of Hydrogen

A molten carbonate electrolysis cell (MCEC) is capable of separating carbon dioxide from methane reformate while simultaneously electrolyzing water. Methane reformate, for this study, primarily consists of carbon dioxide, hydrogen, methane, and a high percentage of water. Carbon dioxide is required for the operation of a MCEC since a carbonate ion is formed and travels from the reformate channel to the sweep gas channel. In this study, a spatially resolved physical model was developed to simulate an MCEC in a novel hybrid reformer electrolyzer purifier (REP) configuration for high purity hydrogen production from methane and water. REP effectively acts as an electrochemical CO2 purifier of hydrogen. In order to evaluate the performance of REP, a dynamic MCEC stack model was developed based upon previous high temperature molten carbonate fuel cell modeling studies carried out at the National Fuel Cell Research Center at the University of California, Irvine. The current model is capable of capturing both steady state performance and transient behavior of an MCEC stack using established physical models originating from first principals. The model was first verified with REP experimental data at steady state which included spatial temperature profiles. Preliminary results show good agreement with experimental data in terms of spatial distribution of temperature, current density, voltage, and power. The combined effect of steam methane reformation (SMR) and water electrolysis with electrochemical CO2 removal results in 96% dry-basis hydrogen at the cathode outlet of the MCEC. Experimental measurements reported 98% dry-basis hydrogen at the cathode outlet.

scholarly journals Dynamics of Excitation and Inhibition in the Light-Adapted Limulus Eye in situ

1971 ◽  
Vol 58 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Marguerite Biederman-Thorson ◽  
John Thorson
Keyword(s):  
Steady State ◽  
Lateral Inhibition ◽  
Low Frequency ◽  
Dynamic Responses ◽  
Relaxation Processes ◽  
Pass Filter ◽  
Generator Potential ◽  
Low Pass Filter ◽  
Low Pass

The dynamics of spike discharge in eccentric cell axons from the in situ lateral eye of Limulus, under small sinusoidal modulation of light to which the eye is adapted, are described over two decades of light intensity and nearly three decades of frequency. Steady-state lateral inhibition coefficients, derived from the very low-frequency response, average 0.04 at three interommatidial spacings. The gain vs. frequency of a singly illuminated ommatidium is described closely from 0.004 to 0.4 cps by the linear transfer function s0.25; this function also accounts approximately for the measured phase leads, the small signal adaptation following small step inputs, and for Pinter's (1966) earlier low-frequency generator potential data. We suggest that such dynamics could arise from a summation in the generator potential of distributed intensity-dependent relaxation processes along the dendrite and rhabdome. Analysis of the dynamic responses of an eccentric cell with and without simultaneously modulated illumination of particular neighbors indicates an effect equivalent to self-inhibition acting via a first-order low-pass filter with time constant 0.42 sec, and steady-state gain near 4.0. The corresponding filters for lateral inhibition required time constants from 0.35 to 1 sec and effective finite delay of 50–90 msec.

Extended near-IR Spectral Sensitivity and Electroluminescence Properties of Silicon Diode Structure with GaSb/Si Composite Layer

2016 ◽  
Vol 247 ◽  
pp. 61-65 ◽  
Author(s):  
Dmitry L. Goroshko ◽  
Alexander V. Shevlyagin ◽  
Evgeniy Anatolievich Chusovitin ◽  
Konstantin N. Galkin ◽  
Igor M. Chernev ◽  
...  
Keyword(s):  
Spectral Sensitivity ◽  
Wavelength Range ◽  
Room Temperature ◽  
Solid Phase ◽  
Composite Layer ◽  
Solid Phase Epitaxy ◽  
Silicon Matrix ◽  
Near Ir ◽  
Wide Wavelength Range ◽  
Integral Sensitivity

An array of GaSb nanocrystallites (NCs) was formed on Si(001) substrate by solid-phase epitaxy at 500 °C. Owing to the embedded GaSb NCs, p+‑Si/NC‑GaSb/n‑Si mesa diode spectral sensitivity has extended up to 1.6 µm at room temperature, and its integral sensitivity has increased by 4–5% in the wavelength range of 1200–1600 nm, as compared to a conventional Si diode. This result was achieved by embedding only 10 nm of GaSb in the form of NCs inside a silicon matrix. In addition, we could obtain a significant electroluminescence (EL) signal at 120 K in a very wide wavelength range from 1.3 to 2.1 µm (0.95–0.59 eV). The EL spectrum has a broad maximum at 1700 nm (0.73 eV). The threshold pumping current density was as low as 0.75 A/cm2.

scholarly journals Identification of Solar Collector Dynamics Using Physical Model-Based Approach

1994 ◽  
Vol 116 (4) ◽  
pp. 755-763 ◽  
Author(s):  
B. J. Huang ◽  
S. B. Wang
Keyword(s):  
Steady State ◽  
System Dynamics ◽  
Physical Model ◽  
Transfer Functions ◽  
Linear Time ◽  
Operating Conditions ◽  
Distributed Model ◽  
Response Analysis ◽  
Linear Perturbation ◽  
Model Parameters

A system dynamics model of flat-plate solar collectors was derived and identified here. A nonlinear physical model was first derived from a two-node concept and energy conservation principle. The model was then approximated by the linear perturbation equations which were Laplace transformed and solved to lead to a distributed model in terms of the transfer functions. A model reduction was further employed to yield a linear time-invariant model with parameters as functions of steady-state operating conditions. The model parameters were identified by a dynamic test with step inputs at various operating conditions using frequency response analysis and model fitting in frequency domain. The identified parameters were then fitted to a function of steady-state mass flowrate mw. Thus, the model can describe the system dynamics behavior under various operating conditions through the identified parameters. The simulations using the model were shown to agree very well with the test results.

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