scholarly journals Nanocarbon mesh in the flame of aromatic compounds

2021 ◽  
Vol 2086 (1) ◽  
pp. 012214
Author(s):  
O V Vasilyeva ◽  
S I Ksenofontov ◽  
A N Lepaev
Keyword(s):  
Chemical Composition ◽  
Aromatic Compounds ◽  
Dispersed Particles ◽  
Unidentified Species ◽  
Pyrotechnic Composition ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Abstract The soot in the flame of the pyrotechnic composition is presented in a variety of shapes and structures. Part of the dispersed particles consists entirely of carbon. The sizes of such particles are in the submicron range. Another part of the particles contains carbon in the form of nanostructures - needles and tubes. A detailed study of the morphology and chemical composition of dispersed particles on optical and scanning electron microscopes showed the existence of yet another unidentified species of particles - tuba. The resulting formations are micron-sized and retain the properties of nanostructures.

The Influence of Various Etchants on the Quantitative Analysis of Microstructure of Mg-Nd Alloy

2013 ◽  
Vol 197 ◽  
pp. 192-197
Author(s):  
Michał Stopyra ◽  
Andrzej Kiełbus
Keyword(s):  
Quantitative Analysis ◽  
Chemical Composition ◽  
Qualitative Analysis ◽  
Significant Influence ◽  
Master Alloy ◽  
Comparison Of Results ◽  
Program Comparison ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The paper presents the results of the influence of various etchants on the quantitative analysis of microstructure of Mg-Nd master alloy. The methodology of quantitative analysis of these alloys’ microstructure were also presented. Qualitative analysis were done using light and scanning electron microscopes, chemical composition was investigated using EDS method. Seven types of etchants were used. Having chosen suitable images, quantitative analysis were done using Met-Ilo program. Comparison of results showed that chosen etchants didn’t make the significant influence on the quantitative analysis results of the microstructure, despite visible dissimilarities.

Current State of Biological High-Resolution Scanning Electron Microscopy

1988 ◽  
Vol 46 ◽  
pp. 180-181 ◽  
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Performance ◽  
Low Voltage ◽  
Backscattered Electrons ◽  
Lens Position ◽  
Low Voltage Operation ◽  
Signal Collection ◽  
Probe Size ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

A new generation of high performance field emission scanning electron microscopes (FSEM) is now commercially available (JEOL 890, Hitachi S 900, ISI OS 130-F) characterized by an "in lens" position of the specimen where probe diameters are reduced and signal collection improved. Additionally, low voltage operation is extended to 1 kV. Compared to the first generation of FSEM (JE0L JSM 30, Hitachi S 800), which utilized a specimen position below the final lens, specimen size had to be reduced but useful magnification could be impressively increased in both low (1-4 kV) and high (5-40 kV) voltage operation, i.e. from 50,000 to 200,000 and 250,000 to 1,000,000 x respectively.At high accelerating voltage and magnification, contrasts on biological specimens are well characterized1 and are produced by the entering probe electrons in the outmost surface layer within -vl nm depth. Backscattered electrons produce only a background signal. Under these conditions (FIG. 1) image quality is similar to conventional TEM (FIG. 2) and only limited at magnifications >1,000,000 x by probe size (0.5 nm) or non-localization effects (%0.5 nm).

Observation of GaAs/AlAs Superlattice Structures in both Secondary and Backscattcred Electron Imaging Modes with an Ultrahigh Resolution Scanning Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 404-405
Author(s):  
K. Ogura ◽  
A. Ono ◽  
S. Franchi ◽  
P.G. Merli ◽  
A. Migliori
Keyword(s):  
Gaas Layer ◽  
Objective Lens ◽  
Superlattice Structure ◽  
Backscattered Electron ◽  
Instrumental Resolution ◽  
Electron Microscopes ◽  
Superlattice Structures ◽  
Electron Imaging ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

In the last few years the development of Scanning Electron Microscopes (SEM), equipped with a Field Emission Gun (FEG) and using in-lens specimen position, has allowed a significant improvement of the instrumental resolution . This is a result of the fine and bright probe provided by the FEG and by the reduced aberration coefficients of the strongly excited objective lens. The smaller specimen size required by in-lens instruments (about 1 cm, in comparison to 15 or 20 cm of a conventional SEM) doesn’t represent a serious limitation in the evaluation of semiconductor process techniques, where the demand of high resolution is continuosly increasing. In this field one of the more interesting applications, already described (1), is the observation of superlattice structures.In this note we report a comparison between secondary electron (SE) and backscattered electron (BSE) images of a GaAs / AlAs superlattice structure, whose cross section is reported in fig. 1. The structure consist of a 3 nm GaAs layer and 10 pairs of 7 nm GaAs / 15 nm AlAs layers grown on GaAs substrate. Fig. 2, 3 and 4 are SE images of this structure made with a JEOL JSM 890 SEM operating at an accelerating voltage of 3, 15 and 25 kV respectively. Fig. 5 is a 25 kV BSE image of the same specimen. It can be noticed that the 3nm layer is always visible and that the 3 kV SE image, in spite of the poorer resolution, shows the same contrast of the BSE image. In the SE mode, an increase of the accelerating voltage produces a contrast inversion. On the contrary, when observed with BSE, the layers of GaAs are always brighter than the AlAs ones , independently of the beam energy.

Discoasters of the Blue Clay (Middle Miocene) of Malta and Gozo

1978 ◽  
Vol 115 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Minoo Hojjatzadeh
Keyword(s):  
Middle Miocene ◽  
The Family ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

SummaryTwenty-three species of the Family Discoasteraceae Vekshina, 1959 recovered from 18 samples of the Blue Clay at Fort Chambray, Gozo, and 31 samples from Fomm-Ir-Rih Bay, Malta, have been studied under light and scanning electron microscopes. Fourteen Middle Miocene species are reviewed, their stratigraphical ranges and importance as marker species discussed. Nine species are described as new. On the basis of the discoaster species present, a Middle Miocene age (NN.6 Discoaster exilis Zone – NN.7 Discoaster kugleri Zone) for the Blue Clay in Malta and Gozo is suggested.

Research on causes of hot-tearing of AA3003 aluminum billet during DC casting process

2021 ◽  
Vol 95 ◽  
pp. 29-37
Author(s):  
Bach Dao Hong ◽  
◽  
Trung Trinh Van
Keyword(s):  
Chemical Composition ◽  
Casting Process ◽  
Direct Chill ◽  
Hot Tearing ◽  
Cast Aluminum ◽  
Allowable Limit ◽  
Chemical Composition Distribution ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Direct Chill Casting Process

AA3003 aluminum alloy made from raw scrap materials that have the advantage of economical use, but hottearing often occurs in the product billets of the direct chill casting process. This study used ANOVA analysis method for determination of chemical composition of AA3003 aluminum billet products to show influence of chemical composition on hot-tearing ability. The evaluation of the microstructure and chemical composition distribution of the elements by optical and scanning electron microscopes combined with energy dispersive spectroscopy showed the existence of impurities such as Cu, Zn, Fe, Pb exceeding the allowable limit in aluminum billets, especially at grain boundary, which can be the main reason for the hot-tearing of cast aluminum billets.

scholarly journals Ultrastructure of cleistothecia and the stages of life cycle of Microsphaera palczewskii by scanning electron microscope

2014 ◽  
Vol 32 (2) ◽  
pp. 275-278
Author(s):  
Joanna Z. Kadłubowska ◽  
Ewa Kalinowska-Kucharska
Keyword(s):  
Electron Microscope ◽  
Life Cycle ◽  
Scanning Electron Microscope ◽  
Scanning Microscopy ◽  
Developmental Cycle ◽  
Central Poland ◽  
Caragana Arborescens ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Several year long investigations of the developmental cycle of <i>Microsphaera palczewskii</i> occurring on the leaves of <i>Caragana arborescens</i> in Central Poland are reported. The material was studied with light and scanning electron microscopes. The scanning microscopy micrographs of the clistothecia and appendages presented in this report are the first micrographs of this species.

scholarly journals Scanning electron microscope fine tuning using four-bar piezoelectric actuated mechanism

2018 ◽  
Vol 69 (1) ◽  
pp. 24-31
Author(s):  
Khaled S. Hatamleh ◽  
Qais A. Khasawneh ◽  
Adnan Al-Ghasem ◽  
Mohammad A. Jaradat ◽  
Laith Sawaqed ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Inverse Kinematic ◽  
Fine Tuning ◽  
Electron Microscopes ◽  
Tuning Strategy ◽  
Scanning Electron Microscopes ◽  
Fine Tune ◽  
Kinematic Solution ◽  
Scanning Electron

Abstract Scanning Electron Microscopes are extensively used for accurate micro/nano images exploring. Several strategies have been proposed to fine tune those microscopes in the past few years. This work presents a new fine tuning strategy of a scanning electron microscope sample table using four bar piezoelectric actuated mechanisms. The introduced paper presents an algorithm to find all possible inverse kinematics solutions of the proposed mechanism. In addition, another algorithm is presented to search for the optimal inverse kinematic solution. Both algorithms are used simultaneously by means of a simulation study to fine tune a scanning electron microscope sample table through a pre-specified circular or linear path of motion. Results of the study shows that, proposed algorithms were able to minimize the power required to drive the piezoelectric actuated mechanism by a ratio of 97.5% for all simulated paths of motion when compared to general non-optimized solution.

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