scholarly journals Understanding the Structure-Process-Property Balance in PC/PEI blends by Morphology (using Scanning Transmission Electron Microscopy in Field Emission -Scanning Electron Microscopy) and Correlative Deformation Mechanics

2015 ◽  
Vol 21 (S3) ◽  
pp. 613-614 ◽  
Author(s):  
P. Bajaj ◽  
D. Bajaj ◽  
Carl Strom ◽  
H. Zhou ◽  
Kelly Leung
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Scanning Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Deformation Mechanics ◽  
Process Property ◽  
Scanning Electron

Spatial Resolution in Scanning Electron Microscopy and Scanning Transmission Electron Microscopy Without a Specimen Vacuum Chamber

2016 ◽  
Vol 22 (4) ◽  
pp. 754-767 ◽  
Author(s):  
Kayla X. Nguyen ◽  
Megan E. Holtz ◽  
Justin Richmond-Decker ◽  
David A. Muller
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Vacuum Chamber ◽  
Operating Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron

AbstractA long-standing goal of electron microscopy has been the high-resolution characterization of specimens in their native environment. However, electron optics require high vacuum to maintain an unscattered and focused probe, a challenge for specimens requiring atmospheric or liquid environments. Here, we use an electron-transparent window at the base of a scanning electron microscope’s objective lens to separate column vacuum from the specimen, enabling imaging under ambient conditions, without a specimen vacuum chamber. We demonstrate in-air imaging of specimens at nanoscale resolution using backscattered scanning electron microscopy (airSEM) and scanning transmission electron microscopy. We explore resolution and contrast using Monte Carlo simulations and analytical models. We find that nanometer-scale resolution can be obtained at gas path lengths up to 400 μm, although contrast drops with increasing gas path length. As the electron-transparent window scatters considerably more than gas at our operating conditions, we observe that the densities and thicknesses of the electron-transparent window are the dominant limiting factors for image contrast at lower operating voltages. By enabling a variety of detector configurations, the airSEM is applicable to a wide range of environmental experiments including the imaging of hydrated biological specimens and in situ chemical and electrochemical processes.

Preparation of Palm Oil Based Carbon Nanotubes at Various Ferrocene Concentration

2011 ◽  
Vol 364 ◽  
pp. 408-411 ◽  
Author(s):  
M. S. Azmina ◽  
A.B. Suriani ◽  
A.N. Falina ◽  
M. Salina ◽  
J. Rosly ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Palm Oil ◽  
Scanning Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Prominent Peak ◽  
Scanning Electron

In this work, different ferrocene concentration (1.0-8.0 wt%) of bio-hydrocarbon palm oil precursor were utilized to investigate its effect on the characteristics of the produced carbon nanotubes (CNT). The palm oil-ferrocene mixture was vaporized at 450°C and pyrolyzed at 800°C for 30 min time in argon ambient. The CNT were analyzed using field emission scanning electron microscopy, scanning transmission electron microscopy, fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The analysis confirmed different diameter and morphologies of CNT were formed when different ferrocene concentration were used. FTIR spectra show the prominent peak at ~1445, 1736, 2851 and 2925 cm-1that are identified as CNT and C–Hxrespectively.

scholarly journals Cryo-Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)-in-SEM for Bio- and Organo-Mineral Interface Characterization in the Environment

2017 ◽  
Vol 23 (6) ◽  
pp. 1159-1172 ◽  
Author(s):  
Guillaume Wille ◽  
Jennifer Hellal ◽  
Patrick Ollivier ◽  
Annie Richard ◽  
Agnes Burel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Fluorescent Microscopy ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Cryo Scanning Electron Microscopy ◽  
Scanning Electron

AbstractUnderstanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4’,6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy). Fluorescent microscopy revealed that nZVI were embedded in the biofilm structure as aggregates but the resolution was insufficient to observe individual nZVI. Cryo-scanning electron microscopy (SEM) observations showed nZVI aggregates close to bacteria, but it was not possible to confirm direct interactions between nZVI and cell membranes. Scanning transmission electron microscopy in the SEM (STEM-in-SEM) showed that nZVI aggregates could enter the biofilm to a depth of 7–11µm. Bacteria were surrounded by a ring of extracellular polymeric substances (EPS) preventing direct nZVI/membrane interactions. STEM/EDS mapping revealed a co-localization of nZVI aggregates with lectins suggesting a potential role of EPS in nZVI embedding. Thus, the combination of divergent microscopy approaches is a good approach to better understand and characterize biofilm/metal interactions.

An Inexpensive Approach for Bright-Field and Dark-Field Imaging by Scanning Transmission Electron Microscopy in Scanning Electron Microscopy

2014 ◽  
Vol 20 (1) ◽  
pp. 124-132 ◽  
Author(s):  
Binay Patel ◽  
Masashi Watanabe
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Lattice Spacing ◽  
Dark Field ◽  
Bright Field ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron

AbstractScanning transmission electron microscopy in scanning electron microscopy (STEM-in-SEM) is a convenient technique for soft materials characterization. Various specimen-holder geometries and detector arrangements have been used for bright-field (BF) STEM-in-SEM imaging. In this study, to further the characterization potential of STEM-IN-SEM, a new specimen holder has been developed to facilitate direct detection of BF signals and indirect detection of dark-field (DF) signals without the need for substantial instrument modification. DF imaging is conducted with the use of a gold (Au)-coated copper (Cu) plate attached to the specimen holder which directs highly scattered transmitted electrons to an off-axis yttrium-aluminum-garnet (YAG) detector. A hole in the copper plate allows for BF imaging with a transmission electron (TE) detector. The inclusion of an Au-coated Cu plate enhanced DF signal intensity. Experiments validating the acquisition of true DF signals revealed that atomic number (Z) contrast may be achieved for materials with large lattice spacing. However, materials with small lattice spacing still exhibit diffraction contrast effects in this approach. The calculated theoretical fine probe size is 1.8 nm. At 30 kV, in this indirect approach, DF spatial resolution is limited to 3.2 nm as confirmed experimentally.

The Synthesis of Maghemite and Hematite (γ-Fe2O3, α-Fe2O3) Nanospheres

2007 ◽  
Vol 534-536 ◽  
pp. 157-160 ◽  
Author(s):  
M.A. Dar ◽  
S.G. Ansari ◽  
Rizwan Wahab ◽  
Young Soon Kim ◽  
Hyung Shik Shin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Iron Oxide ◽  
Pore Size ◽  
Field Emission ◽  
Sol Gel ◽  
Oxide Powder ◽  
Transmission Electron ◽  
Scanning Electron

Maghemite and hematite nanospheres were synthesized by using the Sol-gel technique. The structural properties of these nanosphere powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM),and pore size distribution.Hematite phase shows crystalline structures.The mean particle size that resulted from BET and XRD analyses were 4.9 nm and 2 nm. The field emission scanning electron microscopy shows iron-oxide powder is composed of nanosized particles, but in nanosized aggregates (agglomeration of particles). It can be seen from transmission electron microscopy that the size of the particles are very small which is in good agreement with the FESEM and the Xray diffraction. TEM and FESEM confirmed that the iron-oxide powder is composed of sizes from 8 nm to 10 nm. The BET and pore size method were employed for specific surface area determination.

scholarly journals Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy

2021 ◽  
Vol 27 (5) ◽  
pp. 943-995
Author(s):  
Jingyue (Jimmy) Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Scanning Transmission Electron Microscopy ◽  
Electron Gun ◽  
Atomic Resolution ◽  
Single Atom ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

Although scanning transmission electron microscopy (STEM) images of individual heavy atoms were reported 50 years ago, the applications of atomic-resolution STEM imaging became wide spread only after the practical realization of aberration correctors on field-emission STEM/TEM instruments to form sub-Ångstrom electron probes. The innovative designs and advances of electron optical systems, the fundamental understanding of electron–specimen interaction processes, and the advances in detector technology all played a major role in achieving the goal of atomic-resolution STEM imaging of practical materials. It is clear that tremendous advances in computer technology and electronics, image acquisition and processing algorithms, image simulations, and precision machining synergistically made atomic-resolution STEM imaging routinely accessible. It is anticipated that further hardware/software development is needed to achieve three-dimensional atomic-resolution STEM imaging with single-atom chemical sensitivity, even for electron-beam-sensitive materials. Artificial intelligence, machine learning, and big-data science are expected to significantly enhance the impact of STEM and associated techniques on many research fields such as materials science and engineering, quantum and nanoscale science, physics and chemistry, and biology and medicine. This review focuses on advances of STEM imaging from the invention of the field-emission electron gun to the realization of aberration-corrected and monochromated atomic-resolution STEM and its broad applications.

High-resolution scanning electron microscopy

1987 ◽  
Vol 45 ◽  
pp. 530-533
Author(s):  
T. Nagatani
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Field Emission ◽  
Scanning Transmission Electron Microscope ◽  
Objective Lens ◽  
Second Development ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron

Although the main development of scanning electron microscopy (SEM) has been accomplished mostly by the Cambridge group and it has not been changed so much for about two decades, it should be noted that there have been two important developments to pursuing high resolution of better than 1nm.Most notably, use of a field emission gun developed by Crewe et al for the scanning transmission electron microscope (STEM) to form a fine electron beam has been most effective in SEMs due to its high brightness and low energy spread. Thus, several models of field emission (FE) SEMs have been developed in the early ’70s and commercialized with a resolution of 2∼3nm at around 30kV.The second development is to use a highly excited objective lens. The specimen has to be set inside the pole-pieces (so-called “in-lens” type).

Sign in / Sign up

Export Citation Format

Share Document