1,721,039 research outputs found
White Light Channeled Spectrum Interferometry for the On-line Surface Inspection
No full textIn the industries making high volume as well as large area foil products and flexible electronics, the deposition and patterning of multi-layer thin films on large area substrates is often involved in the manufacturing processes. For these types of product, the films must be uniform and largely perfect across most of the area of the foil. To achieve a high product yield, the key challenge is to inspect the foil surface at production speed as well as have the sufficient resolution to detect the defects resulting from the coating and patterning processes. After the effective inspection, further process like local repair technique can be applied to remove the defects.
We present a white light channeled spectrum interferometry (WLCSI) method that is effective for applications in on-line surface inspection because it can obtain a surface profile in a single shot. It has an advantage over existing spectral interferometry techniques by using cylindrical lenses as the objective lens in a Michelson interferometric configuration to enable the measurement of long profiles. The adjustable profile length in our experimental setup, determined by the NA of the illuminating system and the aperture of cylindrical lenses, is up to 10 mm. By translating the tested sample during the measurement procedure, fast and large-scale on-line surface inspection can be achieved.
The performance of the WLCSI was evaluated experimentally by measuring step heights. The measuring results closely align with the calibrated specifications given by the manufacturer as well as the measurement results by the other commercial instrument, which demonstrate that the proposed WLCSI could be applied to production line like the R2R surface inspection, where only defects on the film surface are concerned in terms of the quality control
In-Situ Surface Inspection Using White Light Channelled Spectrum Interferometer
No full textWe introduce a new environmentally robust optical interferometry system
for fast surface profile measurement. The proposed white light channelled spectrum
Interferometer (WLCSI) is effective for applications in on-line surface inspection
because it can obtain a surface profile in a single shot. Compared to the traditional
spectral interferometry techniques, cylindrical lens is used in the Michelson
interferometric objective of our system to achieve the measurement of long profiles.
Combined with a modern high speed CCD camera, general-purpose graphics
processing unit (GPGPU) and multi-core processors computing technology, large
dynamic measurement with a high signal-to-noise ratio is realized. The designed
prototype of WLCSI is presented and its performance was evaluated experimentally
by measuring two surface samples. The measuring results closely align with the
calibrated specifications given by the manufacturer as well as the measurement results
by the other commercial instrument, which shows that the proposed WLCSI could be
applied to production line like the roll-to-toll (R2R) surface inspection where only
defects on the film surface are concerned in terms of the quality contro
Spectral Domain Low- Coherence Interferometry for On-line Surface Inspection
Full text linkWe present an on-line surface measurement technique based on spectral domain low-coherence
interferometry (SD-LCI), which can obtain a one dimensional surface profile with just one shot. This technique has an advantage over existing spectral interferometry in the large scale measurement up to 10 mm in length along the tested surface by using a cylindrical lenses based interferometic objective. In this SD-LCI system, the white light interferogram is spectrally decomposed by a spectrometer to determine the phase, which is encoded as a function of wavenumber along the chromaticity axis. After the phase of the channelled spectral signals is calculated at all wavelengths
simultaneously, the optical path difference (OPD) is determined as the slope of the phase versus
wavenumber. By adding a lateral scanning or rotating the cylindrical lenses, large-scale areal
measurement is achieved as well. The experimental details of measurements on two surface samples
are presented and discussed in this paper
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Nonclassical Spin-Multiplexing Metasurfaces Enabled Multifunctional Meta-Scope
No full textDielectric metasurfaces have emerged as attractive devices for advanced imaging systems because of their high efficiency, ability of wavefront manipulation, and lightweight. The classical spin-multiplexing metasurfaces can only provide two orthogonal circular polarization channels and require high phase contrast which limits their applications. Here, metasurfaces with arbitrary three independent channels are demonstrated by proposing a nonclassical spin-multiplexing approach exploring the low refractive index meta-atoms. A zoom microscope with on-axis tri-foci and a synchronous achiral-chiral microscope with in-plane tri-foci based on silicon nitride metasurfaces are experimentally demonstrated. Based on the on-axis tri-foci metasurface, singlet zoom imaging with three magnifications and a broadband response (blue to red) based on a single metasurface is first demonstrated. A compact microscope (meta-scope) consisting of two metasurfaces with three magnifications of 9.5, 10, and 29X with diffraction-limited resolutions is further constructed, respectively. Utilizing the in-plane tri-foci metasurface, a singlet microscope with three achiral-chiral channels is demonstrated. It offers a magnification of 53X and a diffraction-limited resolution, enabling simultaneous imaging of an object's achiral and chiral properties. Our multifunctional metasurfaces and meta-scope approaches could boost the applications in biological imaging and machine vision.</p
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