A method for measuring the distribution of photothermal properties of translucent materials based on the combination of phase-locked thermal waves and optical tomography

A translucent material and optical tomography technology, which is applied in color/spectral characteristic measurement, material thermal analysis, scattering characteristic measurement, etc., can solve problems such as the inability to accurately measure the distribution of photothermal characteristics of translucent materials

Active Publication Date: 2020-06-09
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problem that the photothermal characteristic distribution of translucent materials cannot be accurately measured at present, the present invention

Method used

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  • A method for measuring the distribution of photothermal properties of translucent materials based on the combination of phase-locked thermal waves and optical tomography
  • A method for measuring the distribution of photothermal properties of translucent materials based on the combination of phase-locked thermal waves and optical tomography
  • A method for measuring the distribution of photothermal properties of translucent materials based on the combination of phase-locked thermal waves and optical tomography

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specific Embodiment approach 1

[0082] A method for measuring the distribution of photothermal properties of translucent materials based on the combination of phase-locked thermal waves and optical tomography, comprising the following steps:

[0083] Step 1: Material reconstruction physical model such as figure 1 As shown, use LIT technology to identify the position of inclusions in the material; LIT technology is lock-in thermal imaging technology;

[0084] Step 2: Assign the optical and thermal properties of the background material to the inclusions as the initial values ​​of the optical and thermal properties of the inclusions; the optical properties include absorption coefficient and scattering coefficient, and the thermal properties are thermal conductivity;

[0085] Step 3: Invert the absorption coefficient, scattering coefficient and thermal conductivity of the inclusions initially determined in step 1 through the SQP algorithm; the SQP algorithm is a sequential quadratic programming algorithm;

[00...

specific Embodiment approach 2

[0094] The specific process of using LIT technology to identify the position of inclusions in the material in the method for measuring the distribution of photothermal properties of translucent materials based on the combination of phase-locked thermal wave and optical tomography described in this embodiment is as follows:

[0095] Irradiating the material with a sine wave radiation source can obtain a sine wave thermal signal on the surface of the material. The thermal response is determined by the physical properties of the material. The thermal and optical properties of the material are determined according to the measurement signal. The infrared sine wave laser heat flow is expressed by the following formula:

[0096] q laser =q am sin(2πf e t) (1)

[0097] In the formula, q am and f e represent the peak heat flux and frequency of the incident laser, respectively, and t represents the time;

[0098] The discrete correlation algorithm is used to extract the amplitude a...

specific Embodiment approach 3

[0113] The SQP algorithm calculation process required for the process of determining the absorption coefficient, scattering coefficient and thermal conductivity of the inclusions in step 3 described in this embodiment is as follows:

[0114] Consider a nonlinear programming problem of the form:

[0115] min F(x)

[0116] Constraint c i (x)=0i∈E={1,2,...,m e} (20)

[0117] c i (x)≥0i∈I'={m e +1,me +2,...,m}

[0118] In the formula, F(x) is the objective function to be optimized, specifically the objective function F corresponding to the reconstruction of the absorption coefficient and scattering coefficient 1 Or reconstruct the corresponding objective function F of the thermal conductivity 2 ; x represents the parameter to be reconstructed (reconstructed parameter, representing absorption absorption coefficient, scattering coefficient or thermal conductivity); c i Indicates constraints, m, m e Represent the number of total constraints and equality constraints; E repres...

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Abstract

The invention provides a method for measuring photothermal characteristic distribution of a translucent material on the basis of combination of lock-in thermal waves and optical tomography, relates tothe technical field of measurement of photothermal physical properties of the translucent material, and aims to solve the problem that photothermal characteristic distribution of the translucent material cannot be measured accurately at present. The method comprises the following steps: firstly, position of an inclusion in the material is recognized with LIT (lock-in thermography), then the inclusion is endowed with optical and thermal physical properties of a background material, and the properties serve as initial values of optical and thermal physical properties of the inclusion, and preliminarily determined absorption coefficient, scattering coefficient and thermal conductivity coefficient of the inclusion are subjected to inversion with an SQP (sequential quadratic programming) algorithm; photothermal characteristic distribution of the translucent material is finally determined on the basis of an LIT-SQP algorithm for reconstruction of photothermal characteristic distribution ofthe translucent material. The method combines the advantage of the LIT for rapid locating of the inclusion and the advantage of the SQP algorithm for accurate reconstruction of the photothermal characteristics of the material, and is applicable to measurement of photothermal characteristic distribution of the translucent material.

Description

technical field [0001] The invention relates to the technical field of photothermal physical property measurement of translucent materials. Background technique [0002] Translucent materials are widely used in scientific fields such as industrial production, biomedicine, and information communication. The most common translucent materials in daily life are air, water, glass, plastic, and lenses (polyester resin); in the civil industry, such as ceramic component parts of automobile engines; in the aerospace field, in the extreme environment of spacecraft Heat protection ceramic heat insulation protective layer, high temperature resistant components of turbine engines; biological tissues in the field of biomedical research, such as brain tissue, skin, etc., all belong to the category of translucent materials. [0003] Absorption coefficient, scattering coefficient and thermal conductivity are important parameters to characterize the radiative transmission and thermal conduct...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N25/20G01N25/00G01N21/47G01N21/31
CPCG01N21/31G01N21/47G01N25/00G01N25/20
Inventor 齐宏王申领于晓滢孙双成任亚涛阮立明赵春晖
Owner HARBIN INST OF TECH
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