scholarly journals Method for the Manual Analysis of Moiré Structures in STM images

ChemPhysChem ◽  
2021 ◽  
Author(s):  
Sebastian Günther ◽  
Patrick Zeller ◽  
Bernhard Böller ◽  
Joost Wintterlin
Keyword(s):  
Manual Analysis ◽  
Stm Images

A TEM study of electron tunneling in biological macromolecules

1987 ◽  
Vol 45 ◽  
pp. 140-141
Author(s):  
J. A. Panitz
Keyword(s):  
Stark Effect ◽  
Electron Tunneling ◽  
Imaging Modality ◽  
Tunneling Current ◽  
Biological Species ◽  
Scanning Tunneling ◽  
Biological Macromolecules ◽  
Flat Surfaces ◽  
Virus Particles ◽  
Stm Images

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.

Scanning Tunneling Microscopy of Amorphous Carbon Films

1990 ◽  
Vol 48 (1) ◽  
pp. 318-319
Author(s):  
Mircea Fotino ◽  
D.C. Parks
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Amorphous Carbon ◽  
Carbon Films ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Amorphous Carbon Films ◽  
Image Optimization ◽  
Step Procedure ◽  
Stm Images

In the last few years scanning tunneling microscopy (STM) has made it possible and easily accessible to visualize surfaces of conducting specimens at the atomic scale. Such performance allows the detailed characterization of surface morphology in an increasing spectrum of applications in a wide variety of fields. Because the basic imaging process in STM differs fundamentally from its equivalent in other well-established microscopies, good understanding of the imaging mechanism in STM enables one to grasp the correct information content in STM images. It thus appears appropriate to explore by STM the structure of amorphous carbon films because they are used in many applications, in particular in the investigation of delicate biological specimens that may be altered through the preparation procedures.All STM images in the present study were obtained with the commercial instrument Nanoscope II (Digital Instruments, Inc., Santa Barbara, California). Since the importance of the scanning tip for image optimization and artifact reduction cannot be sufficiently emphasized, as stressed by early analyses of STM image formation, great attention has been directed toward adopting the most satisfactory tip geometry. The tips used here consisted either of mechanically sheared Pt/Ir wire (90:10, 0.010" diameter) or of etched W wire (0.030" diameter). The latter were eventually preferred after a two-step procedure for etching in NaOH was found to produce routinely tips with one or more short whiskers that are essentially rigid, uniform and sharp (Fig. 1) . Under these circumstances, atomic-resolution images of cleaved highly-ordered pyro-lytic graphite (HOPG) were reproducibly and readily attained as a standard criterion for easily recognizable and satisfactory performance (Fig. 2).

Refugees’ dehumanization in the Spanish media: A corpus-assisted study within the semantic preference framework

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Gema Alcaraz-Mármol ◽  
Jorge Soto-Almela
Keyword(s):  
Civil War ◽  
Middle East ◽  
Economic Burden ◽  
Digital Libraries ◽  
Armed Conflicts ◽  
Critical Discourse ◽  
Manual Analysis ◽  
Syrian Civil War ◽  
The Media

AbstractThe dehumanization of migrants and refugees in the media has been the object of numerous critical discourse analyses and metaphor-based studies which have primarily dealt with English written news articles. This paper, however, addresses the dehumanizing language which is used to refer to refugees in a 1.8-million-word corpus of Spanish news articles collected from the digital libraries of El Mundo and El País, the two most widely read Spanish newspapers. Our research particularly aims to explore how the dehumanization of the lemma refugiado is constructed through the identification of semantic preferences. It is concerned with synchronic and diachronic aspects, offering results on the evolution of refugees’ dehumanization from 2010 to 2016. The dehumanizing collocates are determined via a corpus-based analysis, followed by a detailed manual analysis conducted in order to label the different collocates of refugiado semantically and classify them into more specific semantic subsets. The results show that the lemma refugiado usually collocates with dehumanizing words that express, by frequency order, quantification, out-of-control phenomenon, objectification, and economic burden. The analysis also demonstrates that the collocates corresponding to these four semantic subsets are unusually frequent in the 2015–16 period, giving rise to seasonal collocates strongly related to the Syrian civil war and other Middle-East armed conflicts.

scholarly journals Automated analysis of 3D-echocardiography using spatially registered patient-specific CMR meshes

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
D Zhao ◽  
E Ferdian ◽  
GD Maso Talou ◽  
GM Quill ◽  
K Gilbert ◽  
...  
Keyword(s):  
New Zealand ◽  
Interobserver Variability ◽  
Ground Truth ◽  
Automated Analysis ◽  
3D Echocardiography ◽  
Training Data ◽  
Patient Specific ◽  
Manual Analysis ◽  
Lv Mass ◽  
3D Echo

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart Foundation (NHF) of New Zealand Health Research Council (HRC) of New Zealand Artificial intelligence shows considerable promise for automated analysis and interpretation of medical images, particularly in the domain of cardiovascular imaging. While application to cardiac magnetic resonance (CMR) has demonstrated excellent results, automated analysis of 3D echocardiography (3D-echo) remains challenging, due to the lower signal-to-noise ratio (SNR), signal dropout, and greater interobserver variability in manual annotations. As 3D-echo is becoming increasingly widespread, robust analysis methods will substantially benefit patient evaluation.  We sought to leverage the high SNR of CMR to provide training data for a convolutional neural network (CNN) capable of analysing 3D-echo. We imaged 73 participants (53 healthy volunteers, 20 patients with non-ischaemic cardiac disease) under both CMR and 3D-echo (<1 hour between scans). 3D models of the left ventricle (LV) were independently constructed from CMR and 3D-echo, and used to spatially align the image volumes using least squares fitting to a cardiac template. The resultant transformation was used to map the CMR mesh to the 3D-echo image. Alignment of mesh and image was verified through volume slicing and visual inspection (Fig. 1) for 120 paired datasets (including 47 rescans) each at end-diastole and end-systole. 100 datasets (80 for training, 20 for validation) were used to train a shallow CNN for mesh extraction from 3D-echo, optimised with a composite loss function consisting of normalised Euclidian distance (for 290 mesh points) and volume. Data augmentation was applied in the form of rotations and tilts (<15 degrees) about the long axis. The network was tested on the remaining 20 datasets (different participants) of varying image quality (Tab. I). For comparison, corresponding LV measurements from conventional manual analysis of 3D-echo and associated interobserver variability (for two observers) were also estimated. Initial results indicate that the use of embedded CMR meshes as training data for 3D-echo analysis is a promising alternative to manual analysis, with improved accuracy and precision compared with conventional methods. Further optimisations and a larger dataset are expected to improve network performance. (n = 20) LV EDV (ml) LV ESV (ml) LV EF (%) LV mass (g) Ground truth CMR 150.5 ± 29.5 57.9 ± 12.7 61.5 ± 3.4 128.1 ± 29.8 Algorithm error -13.3 ± 15.7 -1.4 ± 7.6 -2.8 ± 5.5 0.1 ± 20.9 Manual error -30.1 ± 21.0 -15.1 ± 12.4 3.0 ± 5.0 Not available Interobserver error 19.1 ± 14.3 14.4 ± 7.6 -6.4 ± 4.8 Not available Tab. 1. LV mass and volume differences (means ± standard deviations) for 20 test cases. Algorithm: CNN – CMR (as ground truth). Abstract Figure. Fig 1. CMR mesh registered to 3D-echo.

Lexicographer’s Lacunas or How to Deal with Missing Representative Dictionary Forms on the Example of Czech

2019 ◽  
Author(s):  
Dominika Kováříková ◽  
Michal Škrabal ◽  
Václav Cvrček ◽  
Lucie Lukešová ◽  
Jiří Milička
Keyword(s):  
Grammatical Category ◽  
Manual Analysis ◽  
Different Types ◽  
Word Forms ◽  
Frequency Threshold

Abstract When compiling a list of headwords, every lexicographer comes across words with an unattested representative dictionary form in the data. This study focuses on how to distinguish between the cases when this form is missing due to a lack of data and when there are some systemic or linguistic reasons. We have formulated lexicographic recommendations for different types of such ‘lacunas’ based on our research carried out on Czech written corpora. As a prerequisite, we calculated a frequency threshold to find words that should have the representative form attested in the data. Based on a manual analysis of 2,700 nouns, adjectives and verbs that do not, we drew up a classification of lacunas. The reasons for a missing dictionary form are often associated with limited collocability and non-preference for the representative grammatical category. Findings on unattested word forms also have significant implications for language potentiality.

Automatic Threat Assessment of Malware Based on Behavior Analysis

2014 ◽  
Vol 644-650 ◽  
pp. 2952-2956
Author(s):  
Jian Guo Jiang ◽  
Xin Jian Ma ◽  
Xin Liang Qiu ◽  
Min Yu ◽  
Chao Liu
Keyword(s):  
Behavior Analysis ◽  
Practical Problem ◽  
Threat Assessment ◽  
Automatic Analysis ◽  
Experimental Result ◽  
Automatic Identification ◽  
Manual Analysis ◽  
Manual Processing

Automatic analysis of malware is a hot topic in recent years. While many methods were proposed it was still a challenge for automatic identification of malware. For example, scoring was commonly used to indicate threat scale of samples, but this metric was given by manual processing in most case. In this paper, a method to automatically generate the score of analyzed sample was proposed. Combine this method and practical problem, we tested up to 639 samples and got a correctness of 97.3%. Experimental result showed that this method could correctly indicate the threat scale of samples. The results of this paper can also offer some tips for manual analysis.

Chiral Molecular Cavities of Calix[4]Crown on Au(111)

2008 ◽  
Vol 8 (11) ◽  
pp. 5702-5707 ◽  
Author(s):  
Ge-Bo Pan ◽  
Jun Luo ◽  
Qi-Yu Zheng ◽  
Li-Jun Wan
Keyword(s):  
Self Assembly ◽  
Chiral Recognition ◽  
Scanning Tunneling ◽  
Racemic Mixture ◽  
Tunneling Microscopy ◽  
Geometrical Structures ◽  
Simple Method ◽  
Ordered Structures ◽  
Ordered Arrays ◽  
Stm Images

Well-ordered arrays of chiral molecular cavities have been constructed by self-assembly of inherently chiral calix[4]crown on Au(111) in 0.1 M HClO4 solution and investigated by scanning tunneling microscopy (STM). The chiral features are clearly observed in high resolution STM images. It is found that the adsorption of the two enantiomers results in the same ordered structures with upright orientation on Au(111). Moreover, only phase separation has been observed for the racemic mixture of the two enantiomers in the experiment. This is mainly due to the weak molecule-substrate interaction as well as asymmetric geometrical structures of the two enantiomers. The present study provides a simple method for construction of ordered arrays of chiral molecular cavities, which are of potential in chemical sensors, chiral recognition, and nonlinear optics.

The Atomic Structure of the UO2 (111) Surface and the Effects of Additional Surface Oxygen Studied by Elevated Temperature STM

1998 ◽  
Vol 05 (01) ◽  
pp. 315-320 ◽  
Author(s):  
C. Muggelberg ◽  
M. R. Castell ◽  
G. A. D. Briggs ◽  
D. T. Goddard
Keyword(s):  
Elevated Temperature ◽  
Atomic Structure ◽  
Uranium Oxide ◽  
The Other ◽  
Surface Oxygen ◽  
Surface Termination ◽  
Sample Bias ◽  
Different Types ◽  
Stm Images ◽  
Mobile Oxygen

The structure of the UO 2+x (111) surface has been investigated by elevated temperature STM. Images of atomic terraces reveal two different types of surface termination. One of them corresponds to the stoichiometric UO 2 (111) surface and can be resolved atomically in empty state images above ~ 1.6 V sample bias. The observed (1 × 1) ordering is thought to be due to uranium states because its occurrence corresponds to the bottom of the empty uranium 5f band. On these terraces mobile oxygen forms a local [Formula: see text] superstructure. The other terrace type observed on top of the UO 2+x (111) surface is thought to be a phase of a higher uranium oxide which has grown epitaxially.

Surface Structures of Phosphorus and Indium on Si(111)

1998 ◽  
Vol 05 (01) ◽  
pp. 69-76
Author(s):  
F. P. Netzer ◽  
L. Vitali ◽  
J. Kraft ◽  
M. G. Ramesy
Keyword(s):  
Elevated Temperature ◽  
Room Temperature ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Diffusion Limited ◽  
Lower Terrace ◽  
Surface Reconstructions ◽  
Low Energy Electron ◽  
Stm Images

The interaction of vapor phase P2 with the [Formula: see text] monolayer surface at room temperature and elevated temperature has been monitored by scanning tunneling microscopy (STM) and spectroscopy (STS) in conjunction with Auger electron spectroscopy and low-energy electron diffraction (LEED). The surface rection can be readily followed by STM because of the very different contrast of the reacted areas in the STM images. The reaction develops around overlayer defects at room temperature and appears to be diffusion-limited, whereas at 300°C the reaction is initiated at the step edges, from which the reaction front progresses onto the lower terrace areas. At elevated temperature several ordered surface reconstructions, showing different STS fingerprints, are detected on the P–In/Si(111) surfaces, which are associated tentatively with P- and Si-terminated structures and an ordered InP phase.

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