Quantitative Analysis in High Resolution Transmission Scanning Microscopy

1971 ◽  
Vol 29 ◽  
pp. 24-25
Author(s):  
A. V. Crewe ◽  
J. Wall
Keyword(s):  
Quantitative Analysis ◽  
High Resolution ◽  
Cross Sections ◽  
High Efficiency ◽  
High Spatial Resolution ◽  
Incident Beam ◽  
Quantitative Information ◽  
Additive Functions ◽  
Scanning Microscope ◽  
Scattering Cross Sections

The scanning microscope is ideally suited for gathering quantitative information about an object, since its outputs are voltage signals which are measures of the interactions of the incident beam with the volume of the specimen struck by the beam. These signals vary in real time as the beam scans and can be processed electronically to assign a “number” to each element of the scanned matrix.Elastic and inelastic scattering cross sections have been selected as the two useful numbers to characterize a specimen since both are 1) additive functions of specimen composition, 2) unambiguously measurable with high efficiency, 3) Independent of microscope parameters, and 4) measurable with high spatial resolution (<5Å).

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

scholarly journals High-resolution mapping of the NO<sub>2</sub> spatial distribution over Belgian urban areas based on airborne APEX remote sensing

2017 ◽  
Vol 10 (5) ◽  
pp. 1665-1688 ◽  
Author(s):  
Frederik Tack ◽  
Alexis Merlaud ◽  
Marian-Daniel Iordache ◽  
Thomas Danckaert ◽  
Huan Yu ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Urban Areas ◽  
High Spatial Resolution ◽  
European Space Agency ◽  
Correlation Coefficients ◽  
Time Frame ◽  
Quantitative Information ◽  
Data Sets ◽  
Vertical Column

Abstract. We present retrieval results of tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs), mapped at high spatial resolution over three Belgian cities, based on the DOAS analysis of Airborne Prism EXperiment (APEX) observations. APEX, developed by a Swiss-Belgian consortium on behalf of ESA (European Space Agency), is a pushbroom hyperspectral imager characterised by a high spatial resolution and high spectral performance. APEX data have been acquired under clear-sky conditions over the two largest and most heavily polluted Belgian cities, i.e. Antwerp and Brussels on 15 April and 30 June 2015. Additionally, a number of background sites have been covered for the reference spectra. The APEX instrument was mounted in a Dornier DO-228 aeroplane, operated by Deutsches Zentrum für Luft- und Raumfahrt (DLR). NO2 VCDs were retrieved from spatially aggregated radiance spectra allowing urban plumes to be resolved at the resolution of 60  ×  80 m2. The main sources in the Antwerp area appear to be related to the (petro)chemical industry while traffic-related emissions dominate in Brussels. The NO2 levels observed in Antwerp range between 3 and 35  ×  1015 molec cm−2, with a mean VCD of 17.4 ± 3.7  ×  1015 molec cm−2. In the Brussels area, smaller levels are found, ranging between 1 and 20  ×  1015 molec cm−2 and a mean VCD of 7.7 ± 2.1  ×  1015 molec cm−2. The overall errors on the retrieved NO2 VCDs are on average 21 and 28 % for the Antwerp and Brussels data sets. Low VCD retrievals are mainly limited by noise (1σ slant error), while high retrievals are mainly limited by systematic errors. Compared to coincident car mobile-DOAS measurements taken in Antwerp and Brussels, both data sets are in good agreement with correlation coefficients around 0.85 and slopes close to unity. APEX retrievals tend to be, on average, 12 and 6 % higher for Antwerp and Brussels, respectively. Results demonstrate that the NO2 distribution in an urban environment, and its fine-scale variability, can be mapped accurately with high spatial resolution and in a relatively short time frame, and the contributing emission sources can be resolved. High-resolution quantitative information about the atmospheric NO2 horizontal variability is currently rare, but can be very valuable for (air quality) studies at the urban scale.

scholarly journals Broadband CARS Microscopy

2004 ◽  
Vol 12 (6) ◽  
pp. 38-41 ◽  
Author(s):  
Marcus T. Cicerone ◽  
Tak W. Kee
Keyword(s):  
Raman Scattering ◽  
Optical Microscopy ◽  
Spatial Resolution ◽  
Cross Sections ◽  
High Spatial Resolution ◽  
Natural Form ◽  
Ir Microscopy ◽  
Scattering Cross ◽  
Cars Microscopy ◽  
Scattering Cross Sections

A major challenge in optical microscopy is to develop techniques with high spatial resolution, sensitivity, and chemical specificity. The latter, chemical specificity, is typically achieved through some form of labeling, which has potential to alter the nature of the sample under investigation. Raman or infrared (IR) microscopy can be utilized to image samples in their natural form using molecular vibrations as a contrast mechanism. IR microscopy suffers from spatial resolution issues, and spontaneous Raman microscopy suffers from low scattering cross-sections, so that high laser power is often required, introducing the possibility of sample photo-damage. Scattering cross-sections for Coherent Anti-Stokes Raman Scattering (CARS) are typically several orders of magnitude greater than those of spontaneous Raman Scattering. This, in addition to the high spatial resolution inherent in nonlinear optical microscopy, has led CARS microscopy to begin emerging as a powerful, noninvasive technique for biological and material imaging.

scholarly journals Wide Swath and High Resolution Airborne HyperSpectral Imaging System and Flight Validation

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1667 ◽  
Author(s):  
Dong Zhang ◽  
Liyin Yuan ◽  
Shengwei Wang ◽  
Hongxuan Yu ◽  
Changxing Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
High Efficiency ◽  
High Spatial Resolution ◽  
Imaging System ◽  
High Sensitivity ◽  
Field Of View ◽  
High Spectral Resolution ◽  
Wide Swath

Wide Swath and High Resolution Airborne Pushbroom Hyperspectral Imager (WiSHiRaPHI) is the new-generation airborne hyperspectral imager instrument of China, aimed at acquiring accurate spectral curve of target on the ground with both high spatial resolution and high spectral resolution. The spectral sampling interval of WiSHiRaPHI is 2.4 nm and the spectral resolution is 3.5 nm (FWHM), integrating 256 channels coving from 400 nm to 1000 nm. The instrument has a 40-degree field of view (FOV), 0.125 mrad instantaneous field of view (IFOV) and can work in high spectral resolution mode, high spatial resolution mode and high sensitivity mode for different applications, which can adapt to the Velocity to Height Ratio (VHR) lower than 0.04. The integration has been finished, and several airborne flight validation experiments have been conducted. The results showed the system’s excellent performance and high efficiency.

Pressure and Density Dependence of the CH4 and N2 Raman Lines in an Equimolar CH4/N2 Gas Mixture

1992 ◽  
Vol 46 (3) ◽  
pp. 468-471 ◽  
Author(s):  
D. Fabre ◽  
B. Oksengorn
Keyword(s):  
Quantitative Analysis ◽  
Cross Sections ◽  
Pressure Range ◽  
Internal Field ◽  
Point Of View ◽  
Gas Mixture ◽  
Practical Point ◽  
Peak Areas ◽  
Scattering Cross Sections ◽  
Physical Quantities

Experiments have been performed to determine the variations of the peak area for the CH4 and N2 Raman lines along with their frequency shift and broadening, as a function of pressure and density, in the case of an equimolar CH4/N2 gas mixture. A comparison is made between the relative values of the Raman scattering cross sections for the two species and the values of the internal field term, versus density of the mixture, showing that the density dependences of these physical quantities become more dissimilar as density increases. Moreover, the ratio of the peak areas for the CH4 and N2 Raman lines is found to be constant in the entire pressure range used. From a practical point of view, these results for gas mixtures could be useful in quantitative analysis of fluid inclusions in rocks.

Mapping the Structure of a Hydrated Polymer Blend Using Energy-Loss Spectroscopy in the Cryo-STEM

2004 ◽  
Vol 839 ◽  
Author(s):  
Alioscka Sousa ◽  
Abdelaziz Aitouchen ◽  
Matthew Libera
Keyword(s):  
Spatial Distribution ◽  
Energy Loss ◽  
Polymer Blend ◽  
Cross Sections ◽  
Incident Beam ◽  
Two Phase ◽  
Electron Dose ◽  
Spatially Resolved ◽  
Incident Beam Energy ◽  
Scattering Cross Sections

ABSTRACTWe use electron energy-loss spectroscopy (EELS) in the cryo-STEM to determine the spatial distribution of water in a model frozen-hydrated two-phase polymer blend composed of hydrophilic poly(vinylpyrrolidone) (PVP) and hydrophobic poly(styrene) (PS). We demonstrate that it is possible to directly correlate the water spatial distribution with variations in the underlying polymer morphology. HAADF-STEM imaging of both dry and frozen-hydrated specimens shows weak contrast between the polymer phases but gives no information regarding the composition of these phases and no indication of where water might be localized. Spatially-resolved EELS spectra collected at 100 nm pixel size show that this system is composed of discrete PVP-rich domains dispersed in a continuous PS-rich matrix. The PVP-rich domains were found to be hydrated up to a level of ∼ 23 wt%. We have made our compositional maps fully quantitative, given as mass-fraction maps, by measuring the total inelastic scattering cross-sections per unit mass of water, PVP and PS. This is an important quantity which we have determined for an incident beam energy of 200 keV. Hydrated PVP gives rise to hydrogen evolution when irradiated above an electron dose of 1500 e/nm2 as evidenced from changes in the 13 eV region, and this effect gives rise to dose-limited resolution in these experiments.

Micro-structure studies of the molten binary K3AlF6–Al2O3 system by in situ high temperature Raman spectroscopy and theoretical simulation

2018 ◽  
Vol 5 (8) ◽  
pp. 1861-1868 ◽  
Author(s):  
Nan Ma ◽  
Jinglin You ◽  
Liming Lu ◽  
Jian Wang ◽  
Min Wang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Quantitative Analysis ◽  
Raman Scattering ◽  
Cross Sections ◽  
Micro Structure ◽  
Theoretical Simulation ◽  
Scattering Cross ◽  
Scattering Cross Sections

This work was the first to use normalized Raman scattering cross-sections to carry out quantitative analysis in the melts.

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