نتایج جستجو برای: fourier transform spectroscopy

تعداد نتایج: 294509  

Journal: :Applied optics 2001
D W Keith J A Dykema H Hu L Lapson J G Anderson

The interferometer for emission and solar absorption (INTESA) is an infrared spectrometer designed to study radiative transfer in the troposphere and lower stratosphere from a NASA ER-2 aircraft. The Fourier-transform spectrometer (FTS) operates from 0.7 to 50 mum with a resolution of 0.7 cm(-1). The FTS observes atmospheric thermal emission from multiple angles above and below the aircraft. A ...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2006
R M A Azzam

Simple and explicit expressions for the phase shifts that p- and s-polarized light experience in frustrated total internal reflection (FTIR) and optical tunneling by an embedded low-index thin film are obtained. The differential phase shifts in reflection and transmission deltar, deltat are found to be identical, and the associated ellipsometric parameters psir, psit are governed by a simple re...

Journal: :Analytical chemistry 2001
F Ehrentreich L Sümmchen

Wavelet decompositions of Raman spectra were investigated with respect to their usability for spike removal and denoising of the raw data. It could be shown that those operations should be performed sequentially. Suppression of spikes is not straightforwardly possible by wavelet transformation; however, the wavelet transform may be used to recognize the spikes by their first level detail coeffi...

2006
Jie Dong

High-Definition (HD) videos often contain rich details as well as large homogeneous regions. To exploit such a property, Variable Block-size Transforms (VBT) should be in place so that transform block size can adapt to local activities. In this paper, we propose a 16×16 Integer Cosine Transform (ICT) for HD video coding, which is simple and efficient. This 16×16 ICT is integrated into the AVS Z...

2013
Siriporn Taokaew Sutasinee Seetabhawang Pongpun Siripong Muenduen Phisalaphong

A nanocellulose-gelatin (bacterial cellulose gelatin (BCG)) film was developed by a supplement of gelatin, at a concentration of 1%-10% w/v, in a coconut-water medium under the static cultivation of Acetobacter xylinum. The two polymers exhibited a certain degree of miscibility. The BCG film displayed dense and uniform homogeneous structures. The Fourier transform infrared spectroscopy (FTIR) r...

2017
Chanel Fortier

The application of Fourier Transform (FT) spectroscopy instruments has broadened the knowledge and capabilities of textile researchers to study a host of projects including surface modifications of cotton fibers to impart flame retardant capabilities, monitoring aging effects on ancient cellulosic artifacts (Kavkler et al., 2011; Lojewski et al., 2010), determining the amount of dye fixation to...

2015
M. Dokukin I. Sokolov

Dynamic mechanical spectroscopy (DMS), which allows measuring frequency-dependent viscoelastic properties, is important to study soft materials, tissues, biomaterials, polymers. However, the existing DMS techniques (nanoindentation) have limited resolution when used on soft materials, preventing them from being used to study mechanics at the nanoscale. The nanoindenters are not capable of measu...

1995
B. Widrow M. Ball J. M. McCool S. S. Narayan A. M. Peterson M. J. Narasimha

| Based on the least mean squares (LMS) algorithm , the LMS spectrum analyzer can be used to re-cursively calculate the discrete Fourier transform (DFT) of a sliding window of data. In this paper, we compare the LMS spectrum analyzer with the straightforward non-adaptive implementation of the recursive DFT. In particular , we demonstrate the robustness of the LMS spectrum analyzer to the propag...

Journal: :Optics letters 2009
R L Sandberg D A Raymondson C La-O-Vorakiat A Paul K S Raines J Miao M M Murnane H C Kapteyn W F Schlotter

We present what we believe to be the first implementation of Fourier transform (FT) holography using a tabletop coherent x-ray source. By applying curvature correction to compensate for the large angles inherent in high-NA coherent imaging, we achieve image resolution of 89 nm using high-harmonic beams at a wavelength of 29 nm. Moreover, by combining holography with iterative phase retrieval, w...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2011
J S Medina R Prosmiti P Villarreal G Delgado-Barrio J V Alemán

An approximation to the Fourier transform (FT) of the Kohlrausch function (stretched exponential) with shape parameter 0 < β ≤ 1 is presented by using Havriliak-Negami-like functions. Mathematical expressions to fit their parameters α, γ, and τ, as functions of β (0 < β ≤ 1 and 1 < β < 2) are given, which allows a quick identification in the frequency domain of the corresponding shape factor β....

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