A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Thank you for reading principles of optics electromagnetic theory of propagation interference and diffraction of light. As you may know, people have search hundreds times for their favorite novels like this principles of optics electromagnetic theory of propagation interference and diffraction of light, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some infectious bugs inside their computer.

Principles Of Optics Electromagnetic Theory Of Propagation Interference And Diffraction Of Light

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Microplastic debris (<5 mm) is a prolific environmental pollutant, found worldwide in marine, freshwater and terrestrial ecosystems. Interactions between biota and microplastics are prevalent, and there is growing evidence that microplastics can incite significant health effects in exposed organisms. To date, the methods used to quantify such interactions have varied greatly between studies. Here, we critically review methods for sampling, isolating and identifying microplastics ingested by environmentally and laboratory exposed fish and invertebrates. We aim to draw attention to the strengths and weaknesses of the suite of published microplastic extraction and enumeration techniques. Firstly, we highlight the risk of microplastic losses and accumulation during biotic sampling and storage, and suggest protocols for mitigating contamination in the field and laboratory. We evaluate a suite of methods for extracting microplastics ingested by biota, including dissection, depuration, digestion and density separation. Lastly, we consider the applicability of visual identification and chemical analyses in categorising microplastics. We discuss the urgent need for the standardisation of protocols to promote consistency in data collection and analysis. Harmonized methods will allow for more accurate assessment of the impacts and risks microplastics pose to biota and increase comparability between studies.

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Sampling, isolating and identifying microplastics ingested by fish and invertebrates

Introduction to physical polymer science

A new method is suggested by the complementary use of the interference and scanning electron microscopy to measure the mean refractive indices and birefringence of fibers having irregular trans verse section. '

A Contribution to the Study of Optical Properties of Fibers with Irregular Transverse Sections

Two- and multiple-beam interference fringes are used to measure the refractive index of graded index fibres. A general expression considering the refraction of the beam by the graded index fibre has been derived, from which expressions for homogeneous and skin-core fibres can be obtained. Comparison between the results with the method used when neglecting refraction is dealt with using Philips, LDF (TM) optical fibres and drawn polypropylene. Considering the derived expressions in the refractive index determination gives a correction even when a matching liquid is used, this suggests that the refraction method should be used especially for graded index fibre.

http://iopscience.iop.org/article/10.1088/0963-9659/4/3/004/pdf

On the determination of the refractive index of a fibre. II. Graded index fibre

This paper describes the use of interferometric methods in fibre science. Different techniques of double-beam and multiple-beam microinterferometry are given, together with their application in the investigation of fibre properties. The use of the polarizing microscope in this respect is also given. Double-beam and multiple-beam interferometric methods were applied to determine the mean refractive indices and birefringence of polyester fibres. The results are illustrated by microinterferograms. Accurate results are obtained when considering the area under the interference fringe shift representing the path difference integrated across the fibre. The double-beam interference microscope is a quick method for the determination of the optical properties of fibres. The interference fringes produced from the multiple-beam interferometric methods are extremely sharp and the amount of information in this case is considerable. The fringe displacement in this case is proportional to twice the phase difference introduced by the fibre. Therefore, multiple-beam interferometric methods are much more sensitive than the double-beam methods.

The interferometric methods applied to the studies of fibrous materials

Characterization of the optical-functional properties of a waveguide written by an UV-laser into a planar polymer chip

An analysis of multiple-beam Fizeau fringes crossing fibres with irregular transverse sections is given. The area enclosed under the fringe shift is considered to represent the path difference integrated across the fibre. The method is applied to the determination of refractive indicies and birefringence of dralon fibres. Microinterferograms are given for illustration.

http://iopscience.iop.org/article/10.1088/0022-3727/18/9/008/pdf

A.A. Hamza

Papers

A Contribution to the Study of Optical Properties of Fibers with Irregular Transverse Sections

On the determination of the refractive index of a fibre. II. Graded index fibre

The interferometric methods applied to the studies of fibrous materials

Characterization of the optical-functional properties of a waveguide written by an UV-laser into a planar polymer chip

Multiple-beam interferometric studies on fibres with irregular transverse sections