In-situ absolute measurement method for reference surface error of large aperture interferometer based on oblique incidence

Modern optical engineering requires increasingly sophisticated interferometry methods capable of conducting subnanometer scale measurements of the large aperture, high-precision optical component surfaces. However, the accuracy of interferometry measurement is limited to the accuracy with which the surface of the reference mirror employed in the interferometer system is known, and the influence of gravity-induced deformation cannot be ignored. This is addressed in the present work by proposing a three-flat testing method based on multiposition rotation interference absolute surface measurement technology that combines the basic theory of N-position rotation with the separability of surface wavefront functions into sums of even and odd functions. These functions provide the rotational symmetric components of the wavefront, which then enables the absolute surface to be reconstructed based on the N-position rotation measurements. In addition, we propose a mechanical clamping combined with computational method to compensate for the gravity-induced deformations of the flats in the multiposition rotation absolute measurements. The high precision of the proposed absolute surface measurement method is demonstrated via simulations. The results of laboratory experiments indicate that the combination compensation method provides the high-precision surface reconstruction outcomes. The present work provides an important contribution for supporting the interferometry measurement of large aperture, high-precision optical component surfaces.

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Pb Electrodeposition in the Presence of Chlorine Ions on Cu(100): An in Situ Optical Reflectivity Difference Study

MRS Proceedings ◽

10.1557/proc-781-z4.10 ◽

2003 ◽

Vol 781 ◽

Author(s):

J. Gray ◽

W. Schwarzacher ◽

X.D. Zhu

Keyword(s):

Oblique Incidence ◽

Opposite Sign ◽

Bulk Phase ◽

Phase Layer ◽

Optical Reflectivity ◽

Scan Rate ◽

Different Types ◽

Chlorine Ions ◽

High Overpotentials

AbstractWe studied the initial stages of the electrodeposition of Pb in the presence of chlorine ions on Cu(100), using an oblique-incidence optical reflectivity difference (OIRD) technique. The OI-RD results reveal that immediately following the underpotential deposition (UPD) of the first Pb monolayer, two different types of bulk-phase films grow depending upon the magnitude of overpotential and cyclic voltammetry (CV) scan rate. At low overpotentials and/or slow scan rates, we propose that a bulk-phase Pb film grows on top of the UPD monolayer. At high overpotentials and/or fast scan rates, either a PbO, PbCl2, or a rough Pb bulk-phase layer grows on top of the UPD layer such that the reflectivity difference signal from such a film has an opposite sign.

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A magnetic field in situ measurement method of the heating film in atomic sen

IEEE Sensors Journal ◽

10.1109/jsen.2021.3060081 ◽

2021 ◽

pp. 1-1

Author(s):

Xiaoyang Liang ◽

Xinxiu Zhou ◽

Die Hu ◽

Wenfeng Wu ◽

Yuchen Jia

Keyword(s):

Magnetic Field ◽

Measurement Method ◽

In Situ Measurement

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Trial applications at gymnasiums of in-situ sound absorption measurement method by ensemble averaging technique

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-2729 ◽

2021 ◽

Vol 263 (2) ◽

pp. 4532-4537

Author(s):

Toru Otsuru ◽

Reiji Tomiku ◽

Noriko Okamoto ◽

Siwat Lawanwadeekul

Keyword(s):

Measurement Method ◽

Sound Absorption ◽

Glass Wool ◽

Absorption Measurement ◽

Ensemble Averaging ◽

Averaging Technique ◽

In Situ Conditions ◽

Measurement Consistency ◽

Absorption Characteristics

The authors have been published a series of papers on a measurement method for sound absorption characteristics of materials using ensemble averaging technique, i.e., EA method. The papers' results included measurement mechanisms, measurement uncertainty, and so on. Herein, to examine adaptability, especially in in-situ conditions, the EA method is applied to measure absorption characteristics of materials installed in two gymnasiums. A glass-wool panel with the dimension of 0.5 m by 0.5 m by 0.05 m and with the density of 32 kg m^-3 was brought around and measured to check the measurement consistency. Several measurements were conducted during badminton plays were undergoing. Measured sound absorption coefficients revealed that most results agree well with those measured in reverberation rooms. Certain improvement is necessary for the specimen brought to the in-situ measurement to keep the consistency. The inconsistency is considered to originate from unstable conditions between the specimen and floor.

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An Innovative Virtual Chamber Measurement Method Based on Spatial Domain Cancellation Technique for Radiation Emission In Situ Test

IEEE Transactions on Electromagnetic Compatibility ◽

10.1109/temc.2016.2612401 ◽

2017 ◽

Vol 59 (2) ◽

pp. 342-351 ◽

Cited By ~ 2

Author(s):

Zhong-Hao Lu ◽

Liang Ding ◽

Xiao-Hong Lin ◽

Ming-Tuan Lin

Keyword(s):

Measurement Method ◽

Spatial Domain ◽

Radiation Emission ◽

In Situ Test

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Pengembangan Metode DGT (Diffusive Gradient In Thin Film) dengan Binding Gel Fe-Al-Oksida dan Pengikat Silang N,N’-Methylenebisacrylamide untuk Penyerapan Fosfat dalam Air

Jurnal Kimia VALENSI ◽

10.15408/jkv.v0i0.3597 ◽

2015 ◽

pp. 20-25

Author(s):

Asep Saefumullah ◽

Ratsania Rahmaniati H

Keyword(s):

Thin Film ◽

Thin Films ◽

Small Molecule ◽

Aquatic Environment ◽

Contact Time ◽

Measurement Method ◽

High Concentration ◽

Accurate Analysis ◽

Al Oxide

High concentration of phosphates in the water can lead to eutrophication which leads to uncontrolled growth of algae (algae blooming). It underlies the need for determining the concentration of phosphate in the aquatic environment. However, the concentration of phosphate may change during storage of samples so that an accurate analysis difficult to achieve unless carried out in-situ. DGT (Diffusive Gradient in Thin Films) is an in-situ measurement method developed for measuring phosphate and metal. In this study the use of Fe-Al-Oxide as a binding gel that is expected to bind phosphate with a capacity greater than ferrihydrite. N, N'-methylenebisacrylamide is used as a substitute for commercial DGT Crosslinker as crosslinking for a cheaper price and selective for small molecule. Ferrihydrite-DGT and Fe-Al-Oxide-DGT are tested with a variety of concentrations, pH, and contact time. In both methods DGT found that the pH for phosphate measurements performed at pH 3. Capacity of Fe-Al-Oxide binding gel known to be higher than the ferrihydrite binding gel with result Cferrihydrite-DGT:Cstart is 76% and CFe-Al-Oxide-DGT:Cstart is 82%.DOI :http://dx.doi.org/10.15408/jkv.v0i0.3597

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