scholarly journals Angle resolved Scattering Measurement of Multiple Spherical Particles by Fourier Transform

2021 ◽  
pp. 1-1
Author(s):  
Jian Zhang ◽  
Chengzhuang Zhou ◽  
Xiaolong Li ◽  
Datong Wu
Keyword(s):  
Fourier Transform ◽  
Spherical Particles ◽  
Scattering Measurement

scholarly journals Purification, Characterization, and Self-Assembly of the Polysaccharide from Allium schoenoprasum

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1352
Author(s):  
Fengrui Zhang ◽  
Jun Zheng ◽  
Zeyu Li ◽  
Zixuan Cai ◽  
Fengqiao Wang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Tertiary Structure ◽  
Gel Filtration ◽  
Spherical Particles ◽  
Molar Ratio ◽  
Dynamic Light Scattering Measurement ◽  
Cylindrical Micelles ◽  
Allium Schoenoprasum ◽  
Light Scattering Measurement ◽  
Scattering Measurement

The major polysaccharide component from the stalk of Allium schoenoprasum (AssP) was extracted and purified. Gel filtration chromatography purified AssP exhibited a molecular weight of around 1.7 kDa, which was verified by MALDI-ToF-MS. The monosaccharide analysis revealed its composition as rhamnose: arabinose: galactose: glucose: mannose: fructose with a molar ratio of 0.03:2.46:3.71:3.35:1.00:9.93, respectively. The Congo-red assay indicated that there was no tertiary structure of this polysaccharide, however, it self-assembled into a homogenous nanoparticle with a diameter of ~600 nm as revealed by the dynamic light scattering measurement. The solution behavior of this polysaccharide was simulated. The association of this polysaccharide was both time dependent and concentration dependent. AssP forms spherical particles spontaneously as time passes by, and when the AssP concentration increased, the spherical particles increased their sizes and eventually merged into cylindrical micelles. The diversity of AssP hydrodynamic behavior endowed potential versatility in its future applications.

scholarly journals Acaricidal Activity of Nano-Abamectin Against the Two-Spotted Spider Mite; Tetranychus Urticae Koch (Acari: Tetranychidae)

2019 ◽  
pp. 81-86
Author(s):  
Khaled Y. Abdel-Halim ◽  
Fatma Sh. Kalmosh
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Tetranychus Urticae ◽  
Spider Mite ◽  
Acaricidal Activity ◽  
Spherical Particles ◽  
Transmission Electron ◽  
Soybean Plants ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

The efficiency of prepared nano-abamectin was assayed against two-spotted spider mite, Tetranychus urticae (Koch). Prepared formulation showed spherical particles ranged from 66 to 133 nm under examination of Transmission Electron Microscope (TEM) and same pattern of Fourier Transform Infrared (FTIR) spectrum in comparison of conventional acaricide (Vertimecâ). In laboratory trail, toxicity index at LC50 level confirmed that nano-abamectin was greater toxic to adult female, T. urticae (Koch) with value; 30 than Vertimecâ 1.8% EC. Similarly, nano-abamectin reduced the mite fecundity at levels greater than those of Vertimecâ. Regarding field trail, nano-abamectin at rate of 60 ml/ha showed very toxic effects after 3 day of spraying followed by 7 and 14 days on soybean plants achieving % of mortality; 89.98, 83.80 and 76.90%, respectively. These findings showed that, bioactivity of nano-acaricide were many folds higher than conventional acaricide against mite, T. urticae (Koch). However, the biosafety issues may be also addressed.

Comparison of Calculated and Recorded Electron Energy-Loss Spectra of Aluminium and Carbon

1990 ◽  
Vol 48 (2) ◽  
pp. 64-65
Author(s):  
L. Reimer ◽  
R. Oelgeklaus
Keyword(s):  
Fourier Transform ◽  
Energy Loss ◽  
Electron Energy ◽  
Rotational Symmetry ◽  
Mean Free Path ◽  
Single Scattering ◽  
Specimen Thickness ◽  
Two Dimensional ◽  
Image Position ◽  
Electron Energy Loss

Quantitative electron energy-loss spectroscopy (EELS) needs a correction for the limited collection aperture α and a deconvolution of recorded spectra for eliminating the influence of multiple inelastic scattering. Reversely, it is of interest to calculate the influence of multiple scattering on EELS. The distribution f(w,θ,z) of scattered electrons as a function of energy loss w, scattering angle θ and reduced specimen thickness z=t/Λ (Λ=total mean-free-path) can either be recorded by angular-resolved EELS or calculated by a convolution of a normalized single-scattering function ϕ(w,θ). For rotational symmetry in angle (amorphous or polycrystalline specimens) this can be realised by the following sequence of operations :(1)where the two-dimensional distribution in angle is reduced to a one-dimensional function by a projection P, T is a two-dimensional Fourier transform in angle θ and energy loss w and the exponent -1 indicates a deprojection and inverse Fourier transform, respectively.

STEM Study of Surface Plasmon Excitation in Small Spherical Particles

1990 ◽  
Vol 48 (2) ◽  
pp. 42-43
Author(s):  
Daniel UGARTE
Keyword(s):  
Energy Loss ◽  
Spherical Particles ◽  
Small Particles ◽  
Bulk Materials ◽  
Low Loss ◽  
Plasmon Excitation ◽  
Surface Modes ◽  
Surface Plasmon Excitation ◽  
Analytical Electron ◽  
Analytical Electron Microscope

Small particles exhibit chemical and physical behaviors substantially different from bulk materials. This is due to the fact that boundary conditions can induce specific constraints on the observed properties. As an example, energy loss experiments carried out in an analytical electron microscope, constitute a powerful technique to investigate the excitation of collective surface modes (plasmons), which are modified in a limited size medium. In this work a STEM VG HB501 has been used to study the low energy loss spectrum (1-40 eV) of silicon spherical particles [1], and the spatial localization of the different modes has been analyzed through digitally acquired energy filtered images. This material and its oxides have been extensively studied and are very well characterized, because of their applications in microelectronics. These particles are thus ideal objects to test the validity of theories developed up to now.Typical EELS spectra in the low loss region are shown in fig. 2 and energy filtered images for the main spectral features in fig. 3.

FR-IR Molecular Microanalysis System

1990 ◽  
Vol 48 (2) ◽  
pp. 270-271
Author(s):  
John A. Reffner ◽  
William T. Wihlborg
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Integrated System ◽  
Morphological Examination ◽  
Fully Integrated ◽  
Ir Microscopy ◽  
Normal Functions ◽  
Infrared Microspectroscopy ◽  
Infrared Spectral ◽  
Ft Ir

The IRμs™ is the first fully integrated system for Fourier transform infrared (FT-IR) microscopy. FT-IR microscopy combines light microscopy for morphological examination with infrared spectroscopy for chemical identification of microscopic samples or domains. Because the IRμs system is a new tool for molecular microanalysis, its optical, mechanical and system design are described to illustrate the state of development of molecular microanalysis. Applications of infrared microspectroscopy are reviewed by Messerschmidt and Harthcock.Infrared spectral analysis of microscopic samples is not a new idea, it dates back to 1949, with the first commercial instrument being offered by Perkin-Elmer Co. Inc. in 1953. These early efforts showed promise but failed the test of practically. It was not until the advances in computer science were applied did infrared microspectroscopy emerge as a useful technique. Microscopes designed as accessories for Fourier transform infrared spectrometers have been commercially available since 1983. These accessory microscopes provide the best means for analytical spectroscopists to analyze microscopic samples, while not interfering with the FT-IR spectrometer’s normal functions.

The extended Fourier algorithm: Application in discrete optics and electron holography

1994 ◽  
Vol 52 ◽  
pp. 918-919
Author(s):  
E. Voelkl ◽  
L. F. Allard
Keyword(s):  
Fourier Transform ◽  
Fourier Transforms ◽  
Sampling Rate ◽  
Electron Holography ◽  
Optical Bench ◽  
Fourier Space ◽  
Ccd Cameras ◽  
Simulated Image ◽  
Initial Sampling ◽  
Fourier Algorithm

The conventional discrete Fourier transform can be extended to a discrete Extended Fourier transform (EFT). The EFT allows to work with discrete data in close analogy to the optical bench, where continuous data are processed. The EFT includes a capability to increase or decrease the resolution in Fourier space (thus the argument that CCD cameras with a higher number of pixels to increase the resolution in Fourier space is no longer valid). Fourier transforms may also be shifted with arbitrary increments, which is important in electron holography. Still, the analogy between the optical bench and discrete optics on a computer is limited by the Nyquist limit. In this abstract we discuss the capability with the EFT to change the initial sampling rate si of a recorded or simulated image to any other(final) sampling rate sf.

Sign in / Sign up

Export Citation Format

Share Document