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...

| 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...

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...

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....

We describe a new type of Fourier transform (FT) interferometer in which the tunable optical delay between the two arms is realized by using a continuously variable slow-light medium instead of a moving arm as in a conventional setup. The spectral resolution of such a FT interferometer exceeds that of a conventional setup of comparable size by a factor equal to the maximum group index of the sl...

The infrared vibration-rotation bands of SeH have been measured in the X(2)Pi ground state using a Fourier transform spectrometer. The bands were observed in a microwave discharge of a mixture of H(2) and Se in the presence of He. The rotational structure of the 1-0, 2-1, 3-2 bands of the X(2)Pi(3/2) spin component and the 1-0 band of X(2)Pi(1/2) spin component has been observed in the 1800-260...

SnCl4/nano-sawdust was prepared as a carbohydrate-based catalyst containing of tin bearing cellulose units. The catalyst was characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDS). The catalyst was applied successfully as a readily available, inexpensive, biodeg...

Alkali metal dimers are very suitable for studying the perturbations and photodissociation dynamics of excited states, since they have many electronic states which absorb light from the near-infrared to ultraviolet region and some of the excited states predissociate to produce excited atoms.‘” The spectroscopy of alkali dimers has recently attracted renewed interest as they are possible candida...

Widely used higher-dimensional Fourier transform (FT) NMR spectroscopy suffers from two major drawbacks: (i) The minimal measurement time of an N-dimensional FT NMR experiment, which is constrained by the need to sample N - 1 indirect dimensions, may exceed by far the measurement time required to achieve sufficient signal-to-noise ratios. (ii) The low resolution in the indirect dimensions sever...

We study the windowed Fourier transform in the framework of Clifford analysis, which we call the Clifford windowed Fourier transform (CWFT). Based on the spectral representation of the Clifford Fourier transform (CFT), we derive several important properties such as shift, modulation, reconstruction formula, orthogonality relation, isometry, and reproducing kernel. We also present an example to ...