Development and Comparison of the Techniques for Solving the Inverse Problem in Photoacoustics

Abstract In this work, theoretically/mathematically simulated (TMS) model is presented for the photoacoustic (PA) frequency response of a semiconductor in a minimum volume PA cell. By analyzing of the TMS model, the influences of thermal diffusivity and linear coefficient of thermal expansion on silicon sample PA frequency response were investigated and two methods were developed for their estimation. The first one is a self consistent inverse procedure (SCIP) for solving the exponential problems of mathematical physics, based on regression. The second one, a well trained three-layer perceptron with back propagation, based upon theory of artificial neural networks (ANN), is developed and presented. These two inverse problem solving concepts are applied to thermo-elastic characterization of silicon, compared and discussed in the domain of semiconductor characterization.

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Developing the Techniques for Solving the Inverse Problem in Photoacoustics

Atoms ◽

10.3390/atoms7010024 ◽

2019 ◽

Vol 7 (1) ◽

pp. 24 ◽

Cited By ~ 6

Author(s):

Mioljub Nesic ◽

Marica Popovic ◽

Slobodanka Galovic

Keyword(s):

Inverse Problem ◽

Modulation Frequency ◽

Back Propagation ◽

Mathematical Physics ◽

Measurement Range ◽

High Accuracy ◽

Parameter Determination ◽

Minimum Volume ◽

Self Consistent

In this work, theoretically/mathematically simulated models are derived for the photoacoustic (PA) frequency response of both volume and surface optically-absorbing samples in a minimum volume PA cell. In the derivation process, the thermal memory influence of both the sample and the air of the gas column are accounted for, as well as the influence of the measurement chain. Within the analysis of the TMS model, the influence of optical, thermal, and elastic properties of the sample was investigated. This analysis revealed that some of the processes, characterized by certain sample properties, exert their dominance only in limited modulation frequency ranges, which are shown to be dependent upon the choice of the sample material and its thickness. Based on the described analysis, two methods are developed for TMS model parameter determination, i.e., sample properties which dominantly influence the PA response in the measurement range: a self-consistent procedure for solving the exponential problems of mathematical physics, and a well-trained three-layer perceptron with back propagation, based upon theory of neural networks. The results of the application of both inverse problem solving methods are compared and discussed. The first method is shown to have the advantage in the number of properties which are determined, while the second one is advantageous in gaining high accuracy in the determination of thermal diffusivity, explicitly. Finally, the execution of inverse PA problem is implemented on experimental measurements performed on macromolecule samples, the results are discussed, and the most important conclusions are derived and presented.

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Characterization of Solid Particle Erosion Resistance of Ductile Metals Based on Their Properties

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239787 ◽

1985 ◽

Vol 107 (3) ◽

pp. 669-678 ◽

Cited By ~ 4

Author(s):

P. V. Rao ◽

D. H. Buckley

Keyword(s):

Surface Energy ◽

Bulk Modulus ◽

Coefficient Of Thermal Expansion ◽

Glass Particle ◽

Atomic Volume ◽

Linear Coefficient ◽

Ductile Metals ◽

Erosion Rates ◽

First Time

This paper presents experimental results pertaining to spherical glass bead and angular crushed glass particle impingement. A concept of energy absorption to explain the failure of material is proposed and is correlated with the erosion characteristics of several pure metals. Analyses of extensive erosion data indicate that the properties—surface energy, specific melting energy, strain energy, melting point, bulk modulus, hardness, atomic volume—and the product of the parameters—linear coefficient of thermal expansion × bulk modulus × temperature rise required for melting, and ultimate resilience × hardness—exhibit the best correlations. The properties of surface energy and atomic volume are suggested for the first time for correlation purposes and are found to correlate well with erosion rates at different angles of impingement. It further appears that both energy and thermal properties contribute to the total erosion.

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Direct CTE Measurement Technique for the MEMS Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.199 ◽

2006 ◽

Vol 326-328 ◽

pp. 199-202 ◽

Cited By ~ 1

Author(s):

Chung Seog Oh ◽

Sung Hoon Choa ◽

Chang Seung Lee ◽

Hak Joo Lee

Keyword(s):

Thin Films ◽

Thermal Expansion ◽

Coefficient Of Thermal Expansion ◽

Test System ◽

Test Method ◽

Linear Coefficient ◽

Aln Film ◽

Certified Value ◽

Plane Displacement

The accurate characterization of linear coefficient of thermal expansion (CTE) of thin films is vital for predicting the thermal stress, which often results in warpage and failure of a MEMS structure. In this paper, special emphasis is placed on the development of novel test method to extend an ISDG (Interferometric Strain/Displacement Gage) technique to the direct and accurate CTE measurement of MEMS materials, AlN and Au. The freestanding AlN and Au films are 1 μm thick and 5 mm wide. Strain is directly measured by a brand-new digital type ISDG with two Cr lines deposited on the specimen while heating a specimen in a furnace. The whole test system is verified first by measuring the CTE for the NIST’s SRM (Standard Reference Material) 736 (Cu) block. The measured CTE is 17.3 με/oC up to 167 oC, which agrees well with the NIST’s certified value. The CTE of Au is 25.4 ± 1.15 με/oC and that of AlN film is 3.77 ± 0.12 με/oC. The in-plane displacement resolution is about 5 nm at the best circumstances.

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Frequency response characterization of hippocampal CA3 dendrites: Opto-current clamp analysis

Neuroscience Research ◽

10.1016/j.neures.2011.07.511 ◽

2011 ◽

Vol 71 ◽

pp. e120

Author(s):

Seiichiro Sakai ◽

Toru Ishizuka ◽

Hiromu Yawo

Keyword(s):

Frequency Response ◽

Current Clamp ◽

Hippocampal Ca3

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Simulation and prediction of optical characterization of casting (Adamantan-Fulgide) thin films using (CTANNs) approach

International Journal of Modern Physics B ◽

10.1142/s0217979219500930 ◽

2019 ◽

Vol 33 (11) ◽

pp. 1950093 ◽

Cited By ~ 1

Author(s):

A. M. A. EL-Barry ◽

D. M. Habashy

Keyword(s):

Experimental Data ◽

Thin Films ◽

Back Propagation ◽

Optical Characterization ◽

Experimental Information ◽

Training Algorithm ◽

Energy Gaps ◽

Resilient Back Propagation ◽

Good Agreement

For reinforcement, the photochromic field and the cooperation between the theoretical and experimental branches of physics, the computational, theoretical artificial neural networks (CTANNs) and the resilient back propagation (R[Formula: see text]) training algorithm were used to model optical characterizations of casting (Admantan-Fulgide) thin films with different concentrations. The simulated values of ANN are in good agreement with the experimental data. The model was also used to predict values, which were not included in the training. The high precision of the model has been constructed. Moreover, the concentration dependence of both the energy gaps and Urbach’s tail were, also tested. The capability of the technique to simulate the experimental information with best accuracy and the foretelling of some concentrations which is not involved in the experimental data recommends it to dominate the modeling technique in casting (Admantan-Fulgide) thin films.

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An inverse problem for the non-self-adjoint matrix Sturm-Liouville operator

Tamkang Journal of Mathematics ◽

10.5556/j.tkjm.50.2019.2735 ◽

2018 ◽

Vol 50 (1) ◽

pp. 71-102 ◽

Cited By ~ 5

Author(s):

Natalia Pavlovna Bondarenko

Keyword(s):

Inverse Problem ◽

Liouville Operator ◽

Finite Interval ◽

Spectral Characteristics ◽

Sufficient Conditions ◽

Adjoint Matrix ◽

Method Of Spectral Mappings ◽

Sturm Liouville ◽

Necessary And Sufficient

The inverse problem of spectral analysis for the non-self-adjoint matrix Sturm-Liouville operator on a finite interval is investigated. We study properties of the spectral characteristics for the considered operator, and provide necessary and sufficient conditions for the solvability of the inverse problem. Our approach is based on the constructive solution of the inverse problem by the method of spectral mappings. The characterization of the spectral data in the self-adjoint case is given as a corollary of the main result.

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Fracture of Be and Its Alloys - Webb Space Telescope Revisited

10.20944/preprints202111.0503.v1 ◽

2021 ◽

Author(s):

Muhammad Musaddique Ali Rafique

Keyword(s):

Near Infrared ◽

Joint Venture ◽

Coefficient Of Thermal Expansion ◽

Infrared Range ◽

Linear Coefficient ◽

Space Telescope ◽

Hexagonal Close Packed ◽

James Webb Space Telescope ◽

Layer Deposition ◽

Slip Planes

NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (α) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.

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