Application of Phase-Shifting Method in Speckle Interferomtery to Measurement of Micro-Scale Displacement

Baek, Tae-Hyun,Kim, Myung-Soo The Korean Society for Nondestructive Testing 2006 한국비파괴검사학회지 Vol.26 No.3

Speckle interferometry with phase-shifting method has been applied to measurement of micro-scale displacement through optical signal processing. Four-step phase-shifting method by PZT is used to measure out-of-plane displacement in spot-welded cantilever and results of optical experiments are comparable to those of FEM. Phase-shifting method using Fourier transform by PZT is applied to measurement of in-plane displacement on rectangular steel plate with a circular hole. The results of optical experiment agree well with theoretical calculation. New phase-shifting method in speckle interferometry has been implemented with a quarter wave plate. In-plane displacement of specimen is measured by the new phase-shifting method. Results of optical experiment show that the quarter wave plate can be used for phase-shifting method that is cheap and easy to use in speckle interferometry.

Rapid 3D Shape Measurement using Sine Pattern in Phase-Shifting Projection Method

Seung-Sin Kim,Byeong-Mook Chung 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.8

The accuracy and speed of measurement are very important in a 3D measurement system using a DLP projector and a camera. In order to increase the accuracy, the measurement area is divided as small as possible by using a gray code. When the width of the pattern becomes narrower, the square pattern appears as a sine wave, making further division difficult. The sine wave shown here can be subdivided into a range of 2π using the phase-shifting method. This method is the most widely used measurement method called the SBM so far. It is a simple method to increase the accuracy by using gray codes with a short pitch, but there is a problem that the measuring time is lengthened due to an increase in the number of camera shots. In order to reduce the number, it is necessary to use fewer gray codes by using a long-period sine wave in the phase-shifting method. However, if the sine pattern is directly projected, an ideal sine wave cannot be obtained due to the gamma effect, so it is necessary to appropriately modify the fringe pattern and redesign. In this paper, we propose a method to compensate for the gamma eff ect in a sine pattern and show that an ideal sine wave can be generated even with a long periodic phase-shifting method. When the measuring speed and accuracy of the proposed method were compared with the SBM, it was confirmed through experiments that the measuring speed was increased by 25% at the same accuracy and the accuracy of the reference plane was improved by 7 times at the same speed.

Review on the Determination of Frumkin, Langmuir, and Temkin Adsorption Isotherms at Electrode/Solution Interfaces Using the Phase-Shift Method and Correlation Constants

( Jinyoung Chun ),( Jang H. Chun ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.6

This review article described the electrochemical Frumkin, Langmuir, and Temkin adsorption isotherms of over-potentially deposited hydrogen (OPD H) and deuterium (OPD D) for the cathodic H₂ and D₂ evolution reactions (HER, DER) at Pt, Ir, Pt-Ir alloy, Pd, Au, and Re/normal (H₂O) and heavy water (D₂O) solution interfaces. The Frum-kin, Langmuir, and Temkin adsorption isotherms of intermediates (OPD H, OPD D, etc.) for sequential reactions (HER, DER, etc.) at electrode/solution interfaces are determined using the phase-shift method and correlation constants, which have been suggested and developed by Chun et al. The basic procedure of the phase-shift method, the Frumkin, Lang-muir, and Temkin adsorption isotherms of OPD H and OPD D and related electrode kinetic and thermodynamic param-eters, i.e., the fractional surface coverage (0 ≤ θ ≤ 1) vs. potential (E) behavior (θ vs. E), equilibrium constant (K), interaction parameter (g), standard Gibbs energy (ΔG_θ˚) of adsorption, and rate (r) of change of ΔG_θ˚ with θ (0 ≤ θ ≤ 1), at the interfaces are briefly interpreted and summarized. The phase-shift method and correlation constants are useful and effective techniques to determine the Frumkin, Langmuir, and Temkin adsorption isotherms and related electrode kinetic and thermodynamic parameters (θ vs. E, K, g, ΔG_θ˚, r) at electrode/solution interfaces.

Determination of Adsorption Isotherms of Hydrogen on Zirconium in Sulfuric Acid Solution Using the Phase-Shift Method and Correlation Constants

천장호,천진영 한국전기화학회 2009 한국전기화학회지 Vol.12 No.1

The phase-shift method and correlation constants, i.e., the unique electrochemical impedance spectroscopy (EIS) techniques for studying the linear relationship between the behavior (−ϕ vs. E) of the phase shift (90° ≥ -ϕ≥ 0°) for the optimum intermediate frequency and that (θ vs. E) of the fractional surface coverage (0 ≤ θ ≤ 1), have been proposed and verified to determine the Langmuir, Frumkin, and Temkin adsorption isotherms of H and related electrode kinetic and thermodynamic parameters at noble metal (alloy)/aqueous solution interfaces. At a Zr/0.2 M H2SO4 aqueous solution interface, the Frumkin and Temkin adsorption isotherms (θ vs. E), equilibrium constants (K = 1.401 × 10-17 exp(-3.5θ) mol-1 for the Frumkin and K = 1.401 × 10-16 exp(-8.1θ) mol-1 for the Temkin adsorption isotherm), interaction parameters (g = 3.5 for the Frumkin and g = 8.1 for the Temkin adsorption isotherm), rates of change of the standard free energy (r = 8.7 kJ mol-1 for g = 3.5 and r = 20 kJ mol-1 for g = 8.1) of H with θ, and standard free energies (96.13≤ΔG<수식> ≤ 104.8 kJ mol-1 for K= 1.401 × 10-17 exp(-3.5θ) mol-1 and 0 ≤ θ ≤ 1 and 94.44 < ΔG<수식> < 106.5 kJ mol-1 for K= 1.401×10-16 exp(-8.1θ) mol-1 and 0.2 < θ < 0.8) of H are determined using the phase-shift method and correlation constants. At 0.2 < θ < 0.8, the Temkin adsorption isotherm correlating with the Frumkin adsorption isotherm, and vice versa, is readily determined using the correlation constants. The phase-shift method and correlation constants are probably the most accurate, useful, and effective ways to determine the adsorption isotherms of H and related electrode kinetic and thermodynamic parameters at highly corrosion-resistant metal/aqueous solution interfaces.

The Phase-Shift Method for the Langmuir Adsorption Isotherms of Electroadsorbed Hydrogens for the Cathodic H₂ Evolution Reactions at the Poly-Pt Electrode Interfaces

천장호,전상규,이재항,Chun, Jang H.,Jeon, Sang K.,Lee, Jae H. The Korean Electrochemical Society 2002 한국전기화학회지 Vol.5 No.3

순환전압전류 및 교류임피던스 기법을 이용하여 다결정 Pt/0.5M $H_2SO_4$ 및 0.5M LiOH수용액 계면에서 저전위 수소흡착(UPD H) 과 전위 수소흡착(OPD H)에 관한 Langmuir 흡착등온식 $({\theta}\;vs.\;E)$ 을 연구조사 하였다. 계면에서 치적중간주파수일 때 위상이동$(0^{\circ}{\leq}{-\phi}{\leq}90^{\circ})$ 거동은 표면피복율$(1{\geq}{\theta}{\geq}0)$ 거동에 정확하게 상응한다. 위상이 동 방법 즉 최적중간주파수일 때 위상이동 변화$({-\phi}\;vs.\;E)$는 계면에서 음극 $H_2$ 발생 반응에 관한 UPD H와 OPDH의 Langmuir흡착등온식을 결정할 수 있는 새로운 전기화학적 방법으로 사용할 수 있다 다결정 Pt/0.5M $H_2SO_4$ 수용액 계면에서 OPD H의 흡착평형상수(K)와 표준자유에너지$({\Delta}G_{ads})$는 각각 $2.1\times10^{-4}$와 21.0kJ/mol 이다. 다결정 Pt/0.5M LiOH 수용액 계면에서 K는 음전위(E)에 따라 2.7 (UPD H)에서 $6.2\times10^{-6}$ (OPD H) 또는 $6.2\times10^{-6}$(OPD H)에서 2.7 (UPD H)로 전이한다. 유사하게 ${\Delta}G_{ads}$는 E에 따라 -2.5kJ/mol (UPD H)에서 29.7kJ/mol (OPD H)또는 29.7kJ/mol (OPD H)에서 -2.5kJ/mol (UPD H)로 전이한다. K와 ${\Delta}G_{ads}$의 전이는 다결정 Pt전극 표면의 상이한 UPD H와 OPD H의 흡착부위에 기인한다. 다결정 Pt전극 계면에서 UPD H와 OPD H는 음극 $H_2$ 발생 반응에 따른 순차적 과정이 아니라, 수소 흡착부위 자체에 따른 독립적 과정이다. UPD H와 OPD H의 기준은 음극 $H_2$발생 반응과 전위가 아니라, 수소 흡착부위와 과정이다. 수용액에서 음극 $H_2$발생 반응에는 다결정 Pt선 전극이 단결정 Pt(100)원반 전극보다 더 효율적이고 유용하다 위상이동 방법은 열역학적 방법과 상충적이 아니라, 보완적이다. The Langmuir adsorption isotherms of the under-potentially deposited hydrogen (UPD H) and the over-potentially deposited hydrogen (OPD H) at the poly-Pt/0.5M $H_2SO_4$ and 0.5 M LiOH aqueous electrolyte interfaces have been studied using cyclic voltammetric and ac impedance techniques. The behavior of the phase shift $(0^{\circ}{\leq}{-\phi}{\leq}90^{\circ})$ for the optimum intermediate frequency corresponds well to that of the fractional surface coverage $(1{\geq}{\theta}{\geq}0)$ at the interfaces. The phase-shift method, i.e., the phase-shift profile $({-\phi}\;vs.\;E)$ for the optimum intermediate frequency, can be used as a new electrochemical method to determine the Langmuir adsorption isotherms $({\theta}\;vs.\;E)$ of the UPD H and the OPD H for the cathodic $H_2$ evolution reactions at the interfaces. At the poly-Pt/0.5M $H_2SO_4$ aqueous electrolyte interface, the equilibrium constant (K) and the standard free energy $({\Delta}G_{ads})$ of the OPD H are $2.1\times10^{-4}$ and 21.0kJ/mol, respectively. At the poly-Pt/0.5M LiOH aqueous electrolyte interface, K transits from 2.7(UPD H) to $6.2\times10^{-6}$ (OPD H) depending on the cathode potential (E) and vice versa. Similarly, ${\Delta}G_{ads}$ transits from -2.5kJ/mol (UPD H) to 29.7kJ/mol (OPD H) depending on I and vice versa. The transition of K and ${\Delta}G_{ads}$ is attributed to the two distinct adsorption sites of the UPD H and the OPD H on the poly-Pt surface. The UPD H and the OPD H on the poly-Pt surface are the independent processes depending on the H adsorption sites themselves rather than the sequential processes for the cathodic $H_2$ evolution reactions. The criterion of the UPD H and the OPD H is the H adsorption sites and processes rather than the $H_2$ evolution reactions and potentials. The poly-Pt wire electrode is more efficient and useful than the Pt(100) disc electrode for the cathodic $H_2$ evolution reactions in the aqueous electrolytes. The phase-shift method is well complementary to the thermodynamic method rather than conflicting.

위상이동 방법에 의한 Pd/LiOH 전해질 계면의 전극속도론적 패러미터 해설

천장호,문경현,조성칠,손광철,Chun Jang Ho,Mun Kyeong Hyeon,Cho Sung Chil,Son Kwang Chul 한국전기화학회 1999 한국전기화학회지 Vol.2 No.2

위상이동 방법을 이용하여 Pd/0.5 M LiOH전해질 계면의 전극속도론적 패러미터를 정성적으로 해석하였다. 위상이동$(\phi)$은 음전위(E<0) 주파수(f)에 따르며, Pd음극에 흡착된 수소원자$(H_{ads})$의 표면피복율$(\theta)$ 반비례한다. 중간주파수 (10 Hz)에서 위상이동 변화$(\phi\;vs.\;E)$는 Frumkin흡착등온식$(\theta\;vs.\;E)$의 계산 및 도시에 사용할 수 있는 실험적인 방법이다. Pd/0.5 M LiOH전해질 계면에서 $1>{\theta}>0$에 따른 흡착자유에너지변화율(r),흡착평형상수(K),표준자유에너지$({\Delta}G_{\theta})$는 각각 22.3kJ/mol, $3.7\times10^{-3}<K<30,\;13.9>{\Delta}G_{\theta}>-8.4kJ/mol$이다. 1<K<30 또는 $0.38>\theta>0$ 범위에서 수소원자 흡수에 기인한 에너지 방출 즉 발열반응이 Pd음극에서 있다. 전극속도론적 패러미터$(r,\;K,\;{\Delta}G_{\theta}$는 표면피복율$({\theta})$ 또는 위상이동$(\phi)$에 따른다. The electrode kinetic parameters at the Pd/0.5 M LiOH electrolyte interface have been qualitatively studied using the phase-shift method. The phase shift $(\phi)$ depends on both the cathode potential (E>0) and frequency (f), and $\theta$ is inversely proportional to the fractional surface coverage $\theta$. At an intermediate frequency (10 Hz), the phase-shift profile $(\phi\;vs.\;E)$ can be related to the fractional surface coverage $(\theta\;vs.\;E)$. The phase-shift method can be used to estimate or plot the Frumkin adsorption isotherm. The rate (r) of change of the free energy of adsorption with $({\theta})$ is 22.3 kJ/mol. The equilibrium constant (K) for adsorption and the standard free energy $({\Delta}G_{\theta})$ of the adsorbed hydrogen atom $(H_{ads})$ are $3.7\times10^{-3}<K<30,\;13.9>{\Delta}G_{\theta}>-8.4kJ/mol$, respectively. For 1<K<30 or $0.38>\theta>0$, the energy liberation or the exothermic reaction for hydrogen adsorption at the Pd cathode can be occurred. The electrode kinetic parameters $(r,\;K,\;{\Delta}G_{\theta}$ depend on the fractional surface coverage $({\theta})$ or the phase shift $(\phi)$.

자동 위상 이동을 이용한 계통 연계형 태양광 발전 시스템의 고립운전 검출기법

윤중혁,김흥근,최종우,소정훈,유권종 전력전자학회 2007 전력전자학회 논문지 Vol.12 No.2

Islanding of PV systems occurs when the utility grid is removed but the PV systems continue to operate and provide power to local loads. Islanding is one of the serious problems in an electric power system connected with dispersed power sources. This can present safety hazards and the possibility of damage to other electric equipments. In the passive method, the voltage and frequency of PCC are measured and it determines islanding phenomena if their values excess the allowed limits. If the real and reactive power of RLC load and those of the PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding operation in the region where the passive method can not detect it. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new islanding detection method using automatic phase-shift is proposed and its validity is verified through the simulation and experimental results. 계통 연계형 태양광 발전 시스템이 정전 혹은 사고 등으로 계통으로부터 분리되었을 때 태양광 발전 시스템이 배전선 부하를 떠맡아 운전을 계속하는 현상을 고립운전이라 하는데 이런 상태가 지속되면 선로 유지보수자의 안전사고를 야기할 수 있으며 전기설비에 나쁜 영향을 줄 수도 있다. 수동 검출법은 연계점(PCC:Point of Common Coupling)의 전압이나 주파수를 측정하여 한계치를 벗어나면 고립운전으로 판단하는데 RLC 부하의 유효전력과 무효전력이 각각 PV 시스템의 유효전력, 무효전력과 서로 비슷하면 검출할 수 없다. 이 경우 고립운전을 검출하기 위한 다양한 능동 검출법이 제안되었으며 가장 효과적인 방법은 미국 샌디아 연구실(Sandia National Lab)에서 제안한 SFS법(Sandia Frequency Shift method)이다. 본 논문에서는 자동 위상 이동을 이용한 새로운 능동 검출기법을 제안하고 Matlab 시뮬레이션과 실험을 통하여 타당성을 검증하였다.

Improvement of PS Measurement by Phase Compensation Method and Profile Fitting Method in White Light Phase Shifting Interferometry

Dong Hun Ku,Sun Mi Lee,Ha Na Roh,Tai-Wook Kim,Heui Jae Pahk 한국광학회 2018 Current Optics and Photonics Vol.2 No.4

In this paper, methods for decreasing mismeasurement by z-axis vibration in interferometry are proposed with the goal of improving measurement performance. The samples’ 3D height data is acquired by a phase compensation method which eliminates error components due to vibration. Also, the shape of the PS (Photo Spacer) is fitted to sigmoid function and remodeled by using its 3D height data and its CD (Critical Dimension) by subpixel level edge detection. The standard step height sample is measured at sinusoidal vibration of 2~20 Hz frequency and 50 nm amplitude to test improvement of measurement performance. Height repeatability (3σ) of a standard step height sample measurement is improved by more than 40% on average. Three types of PSs are also measured during vibration in the manufacturing process. Reliability of PS height and CD is within 1% in all cases. And repeatability of PS height and CD measurement is improved to a maximum of 65%. Stable measurement is possible during vibration in the manufacturing process by using a phase compensation method and a profile fitting method.

A Hybrid Stress Measurement Using only x-displacements by Phase Shifting Method with Fourier Transform (PSM/FT) in Laser Speckle Interferometry and Least Squares Method

백태현,Thomas J. Rudolphi 한국정밀공학회 2010 International Journal of Precision Engineering and Vol.11 No.1

Stress measurement around the edge of a circular hole at the center of a tensile-loaded plate was performed using an improved hybrid method. Phase-shifting method by Fourier transformation (PSM/FT) in laser speckle interferometry was utilized to measure micro-scale displacement of points away from the edge of the hole. Using few x-displacement and location data only, least-squares method integrated with a Laurent series representation of the stress function and local collocation was used to do reliable stress evaluation on the hole boundary. Traction-free conditions are satisfied at the geometric discontinuity using conformal mapping and analytic continuation. The results of the present improved hybrid method agree well with that of finite element method using commercial software, ABAQUS. Different values of number of term (m) in the complex stress functions were tested to see its effect. In the comparison between input x-displacement data and calculated the hybrid method is effective with an error below 1% in all values of m. On the other hand, it came out that at point of high stress concentration (θ =90°), well-comparable results was attained at decreasing value of m. The best value of m is consistently known to be equal to 1 which results are accurate by less than one percent. Results showed that the method is accurate and reliable as compared with the widely-used ABAQUS.

Measurement of Stress Distribution around a Circular Hole in a Plate under Bending Moment using Phase-shifting Method with Reflective PhotoelasticArrangement

Jie Cheng(정걸),Tae Geun Park(박태근),Tae Hyun Baek(백태현) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

Reflective photoelasticity is a widely used full-field technique for accurately measuring surface strains to determine the stresses in a part or structure during static or dynamic testing. Photoelastic phase-shifting method can be used for the determination of the phase values of isochromatics and isoclinics. Conventional Babinet-soleil compensation method and photoelastic phase-shifting technique were utilized to analyze a specimen with a triangle hole and a circular hole under bending. Three groups of results were obtained by conventional compensation method, 8-step phase-shifting method with reflective-type photoelastic arrangement and FEM (ABAQUS) simulation, respectively. They agree with each other relatively well considering experiment error. The reliability of this combined method can both improve and extend the two conventional methods to be applied to more new fields of stress analysis.