A feasible electrostatic corrector (ECO) is outlined and the principle of the electrostatic correction is elucidated by means of a light-optical analogue. The ECO compensates for the chromatic and the spherical aberration of charged-particle lenses and reduces the resolution limit of a special LVSEM (low-voltage scanning electron microscope) from 6 nm to 1.4 nm. The geometry of the electrodes of the corrector is optimized with respect to the chromatic correction, the maximum strength of the electric field, and the residual higher-order aberrations which limit the resolution. In addition the stability criteria of the electric power supplies are discussed in detail.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1093/jmicro/50.5.383 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Description of changes in chemical bonding along the pathways of chemical reactions by deformation of the molecular electrostatic potential.
J Mol Model
January 2025
Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Krakow, Poland.
Context: The analysis of the changes in the electronic structure along intrinsic reaction coordinate (IRC) paths for model reactions: (i) ethylene + butadiene cycloaddition, (ii) prototype SN2 reaction Cl + CH3Cl, (iii) HCN/CNH isomerization assisted by water, (iv) CO + HF → C(O)HF was performed, in terms of changes in the deformation density (Δr) and the deformation of MEP (ΔMEP). The main goal was to further examine the utility of the ΔMEP as a descriptor of chemical bonding, and to compare the pictures resulting from Δr and ΔMEP. Both approaches clearly show that the main changes in the electronic structure occur in the TS region.
View Article and Find Full Text PDFEffects of Patch Potentials in Electrostatic Double-Layer Forces.
Phys Rev Lett
December 2024
Department of Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
We study the effects of patch potentials in the electrostatic double-layer force. In the limit of small potentials, we derive an analytic expression where the force is additive in terms of the Fourier components of the potential. Moreover, each term has a contribution of the same form as the standard double-layer force with an effective Debye length.
View Article and Find Full Text PDFOn machine learnability of local contributions to interatomic potentials from density functional theory calculations.
Sci Rep
December 2024
Department of Physics, Shahid Beheshti University, Tehran, 1983969411, Iran.
Machine learning interatomic potentials, as a modern generation of classical force fields, take atomic environments as input and predict the corresponding atomic energies and forces. We challenge the commonly accepted assumption that the contribution of an atom can be learned from the short-range local environment of that atom. We employ density functional theory calculations to quantify the decay of the induced electron density and electrostatic potential in response to local perturbations throughout insulating, semiconducting and metallic samples of different dimensionalities.
View Article and Find Full Text PDFGold nanoclusters-based dual-mode ratiometric sensing system for selective and sensitive detection of paraquat.
Talanta
December 2024
Macau Centre for Research and Development in Chinese Medicine, State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, 999078, China. Electronic address:
Unreasonable or illegal utilization of pesticides may lead to pollution of agricultural products, especially with some persistent but effective pesticides. Hence, there is an urgent need to develop sensitive and rapid methods for pesticide detection to ensure the safety of agricultural products. Herein, a dual-mode ratiometric sensing system utilizing two gold nanoclusters (G/R-AuNCs) was designed and constructed for paraquat (PQ) detection, a typical, highly toxic, widely used pesticide.
View Article and Find Full Text PDFRedox potential tuning by calcium ions in a novel c-type cytochrome from an anammox organism.
J Biol Chem
December 2024
Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany. Electronic address:
The electrochemical potentials of redox-active proteins need to be tuned accurately to the correct values for proper biological function. Here we describe a diheme cytochrome c with high heme redox potentials of about +350 mV, despite having a large overall negative charge which typically reduces redox potentials. High resolution crystal structures, spectroelectrochemical measurements and high-end computational methods show how this is achieved: each heme iron has a calcium cation positioned next to it at a distance of only 6.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!