scholarly journals Исследование элементарных процессов МOC-гидридной эпитаксии наногетероструктур на основе арсенида галлия методом атомно-силовой микроскопии

2020 ◽  
Vol 90 (5) ◽  
pp. 826
Author(s):  
П.Б. Болдыревский ◽  
Д.О. Филатов ◽  
А.Д. Филатов ◽  
И.А. Казанцева ◽  
М.В. Ревин ◽  
...  
Keyword(s):  
Defect Formation ◽  
Molar Fraction ◽  
Three Dimensional ◽  
Ingaas Layer ◽  
Reduced Pressure ◽  
Force Microscopy ◽  
Elastic Stresses ◽  
Growth Defects ◽  
Atomic Force ◽  
Hydride Epitaxy

Using atomic force microscopy, we studied the elementary processes of growing (Al, Ga, In) As heterostructures on misoriented GaAs (001) substrates by the method of MOC hydride epitaxy under reduced pressure. It was established that the growth of the epitaxial layers of GaAs and AlGaAs occurs according to a layered mechanism with the formation of macrosteps. The growth of pseudomorphic InGaAs / GaAs (001) layers also occurs by a layered mechanism with the formation of macrosteps. However, if the thickness of the pseudomorphic InxGa1-xAs / GaAs (001) layer exceeds a certain critical value depending on the molar fraction of InAs in the composition of the solid solution (x), the formation of growth defects in the form of three-dimensional islands, the density of which increases with increasing thickness, is observed on the surface of the InGaAs layer InGaAs layer. The formation of three-dimensional InGaAs islands is associated with the relaxation of elastic stresses in the pseudomorphic InGaAs / GaAs (001) layer according to the Stranski-Krastanov mechanism. Keywords: gallium arsenide, AlGaAs, InGaAs, MOC hydride epitaxy, defect formation, Stranski-Krastanov mechanism.

Investigation of growth modes of manganese mercury thiocyanate crystal by atomic force microscopy

2006 ◽  
Vol 39 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Y. L. Geng ◽  
D. Xu ◽  
X. Q. Wang ◽  
X. Q. Hou ◽  
W. F. Guo ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Defect Formation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Growth Modes ◽  
First Time ◽  
Cover Up ◽  
Extra Stress

The growth mechanism and defect formation of the {110} faces of manganese mercury thiocyanate crystals were investigated by atomic force microscopy. A dislocation-controlled mechanism and a two-dimensional nucleation mechanism operate simultaneously during growth. Previous observations showed that two-dimensional nuclei appeared at interstep terraces of spiral hillocks. In this work, it is found for the first time that layers of two-dimensional islands cover up the outcrops of screw dislocations. The spiral hillocks grow fast along the 〈114〉 directions, which is probably due to the small interplanar distances of the {114} faces. Two-dimensional islands often appear as pairs of islands of nearly the same size, at the larger step terraces. Crystallization of the liquid inclusions occurs during the separation of the sample from the mother solution. Small three-dimensional islands, in high density, induce extra stress, which subsequently generates after-growth dislocations.

scholarly journals Acoustic subsurface-atomic force microscopy: Three-dimensional imaging at the nanoscale

2021 ◽  
Vol 129 (3) ◽  
pp. 030901
Author(s):  
Hossein J. Sharahi ◽  
Mohsen Janmaleki ◽  
Laurene Tetard ◽  
Seonghwan Kim ◽  
Hamed Sadeghian ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Three Dimensional ◽  
Three Dimensional Imaging ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Membrane fusion studied by colloidal probes

2021 ◽  
Vol 50 (2) ◽  
pp. 223-237 ◽  
Author(s):  
Hannes Witt ◽  
Filip Savić ◽  
Sarah Verbeek ◽  
Jörn Dietz ◽  
Gesa Tarantola ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Optical Tweezers ◽  
Three Dimensional ◽  
Biological Processes ◽  
Supported Membranes ◽  
Supported Bilayers ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Colloidal Probes

AbstractMembrane-coated colloidal probes combine the benefits of solid-supported membranes with a more complex three-dimensional geometry. This combination makes them a powerful model system that enables the visualization of dynamic biological processes with high throughput and minimal reliance on fluorescent labels. Here, we want to review recent applications of colloidal probes for the study of membrane fusion. After discussing the advantages and disadvantages of some classical vesicle-based fusion assays, we introduce an assay using optical detection of fusion between membrane-coated glass microspheres in a quasi two-dimensional assembly. Then, we discuss free energy considerations of membrane fusion between supported bilayers, and show how colloidal probes can be combined with atomic force microscopy or optical tweezers to access the fusion process with even greater detail.

scholarly journals Measuring the Autocorrelation Function of Nanoscale Three-Dimensional Density Distribution in Individual Cells Using Scanning Transmission Electron Microscopy, Atomic Force Microscopy, and a New Deconvolution Algorithm

2017 ◽  
Vol 23 (3) ◽  
pp. 661-667 ◽  
Author(s):  
Yue Li ◽  
Di Zhang ◽  
Ilker Capoglu ◽  
Karl A. Hujsak ◽  
Dhwanil Damania ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Density Distribution ◽  
Scanning Transmission Electron Microscopy ◽  
Mass Density ◽  
Three Dimensional ◽  
Force Microscopy ◽  
Statistical Measures ◽  
Atomic Force ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractEssentially all biological processes are highly dependent on the nanoscale architecture of the cellular components where these processes take place. Statistical measures, such as the autocorrelation function (ACF) of the three-dimensional (3D) mass–density distribution, are widely used to characterize cellular nanostructure. However, conventional methods of reconstruction of the deterministic 3D mass–density distribution, from which these statistical measures can be calculated, have been inadequate for thick biological structures, such as whole cells, due to the conflict between the need for nanoscale resolution and its inverse relationship with thickness after conventional tomographic reconstruction. To tackle the problem, we have developed a robust method to calculate the ACF of the 3D mass–density distribution without tomography. Assuming the biological mass distribution is isotropic, our method allows for accurate statistical characterization of the 3D mass–density distribution by ACF with two data sets: a single projection image by scanning transmission electron microscopy and a thickness map by atomic force microscopy. Here we present validation of the ACF reconstruction algorithm, as well as its application to calculate the statistics of the 3D distribution of mass–density in a region containing the nucleus of an entire mammalian cell. This method may provide important insights into architectural changes that accompany cellular processes.

High-resolution transmission electron microscopic investigations of molybdenum thin films on faceted α-Al2O3

2005 ◽  
Vol 38 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Leonore Wiehl ◽  
Jens Oster ◽  
Michael Huth
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Epitaxial Relationship ◽  
Electron Microscopic ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Α Al2o3 ◽  
Relationship Of

Epitaxially grown Mo films on a faceted corundum (α-Al2O3)mplane were investigated by transmission electron microscopy. Low- and high-resolution images were taken from a cross-section specimen cut perpendicular to the facets. It was possible to identify unambiguously the crystallographic orientation of these facets and explain the considerable deviation (∼10°) of the experimental interfacet angle, as measured with atomic force microscopy (AFM), from the expected value. For the first time, proof is given for a smooth \{10\bar{1}1\} facet and a curvy facet with orientation near to \{10\bar{1}\bar{2}\}. Moreover, the three-dimensional epitaxial relationship of an Mo film on a faceted corundummsurface was determined.

scholarly journals Tip-Based Nanomachining on Thin Films: A Mini Review

2021 ◽  
Author(s):  
Shunyu Chang ◽  
Yanquan Geng ◽  
Yongda Yan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Data Storage ◽  
Three Dimensional ◽  
Maintenance Cost ◽  
Two Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current State ◽  
Two Dimensional Materials

AbstractAs one of the most widely used nanofabrication methods, the atomic force microscopy (AFM) tip-based nanomachining technique offers important advantages, including nanoscale manipulation accuracy, low maintenance cost, and flexible experimental operation. This technique has been applied to one-, two-, and even three-dimensional nanomachining patterns on thin films made of polymers, metals, and two-dimensional materials. These structures are widely used in the fields of nanooptics, nanoelectronics, data storage, super lubrication, and so forth. Moreover, they are believed to have a wide application in other fields, and their possible industrialization may be realized in the future. In this work, the current state of the research into the use of the AFM tip-based nanomachining method in thin-film machining is presented. First, the state of the structures machined on thin films is reviewed according to the type of thin-film materials (i.e., polymers, metals, and two-dimensional materials). Second, the related applications of tip-based nanomachining to film machining are presented. Finally, the current situation of this area and its potential development direction are discussed. This review is expected to enrich the understanding of the research status of the use of the tip-based nanomachining method in thin-film machining and ultimately broaden its application.

scholarly journals Multiscale three-dimensional surface reconstruction and surface roughness of porcine left anterior descending coronary arteries

2019 ◽  
Vol 6 (9) ◽  
pp. 190915 ◽  
Author(s):  
Hanna E. Burton ◽  
Rachael Cullinan ◽  
Kyle Jiang ◽  
Daniel M. Espino
Keyword(s):  
Surface Roughness ◽  
Coronary Arteries ◽  
Medical Devices ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Force Microscopy ◽  
Optical Scanning ◽  
Atomic Force ◽  
Reconstructed Surface ◽  
Dimensional Surface

The aim of this study was to investigate the multiscale surface roughness characteristics of coronary arteries, to aid in the development of novel biomaterials and bioinspired medical devices. Porcine left anterior descending coronary arteries were dissected ex vivo , and specimens were chemically fixed and dehydrated for testing. Surface roughness was calculated from three-dimensional reconstructed surface images obtained by optical, scanning electron and atomic force microscopy, ranging in magnification from 10× to 5500×. Circumferential surface roughness decreased with magnification, and microscopy type was found to influence surface roughness values. Longitudinal surface roughness was not affected by magnification or microscopy types within the parameters of this study. This study found that coronary arteries exhibit multiscale characteristics. It also highlights the importance of ensuring consistent microscopy parameters to provide comparable surface roughness values.

scholarly journals The extruded non-template strand determines the architecture of R-loops

2019 ◽  
Vol 47 (13) ◽  
pp. 6783-6795 ◽  
Author(s):  
Yeraldinne Carrasco-Salas ◽  
Amélie Malapert ◽  
Shaheen Sulthana ◽  
Bastien Molcrette ◽  
Léa Chazot-Franguiadakis ◽  
...  
Keyword(s):  
Single Molecule ◽  
Genome Stability ◽  
Three Dimensional ◽  
Dna Breaks ◽  
Yeast Gene ◽  
Physical Constraints ◽  
Force Microscopy ◽  
Template Strand ◽  
Atomic Force

Abstract Three-stranded R-loop structures have been associated with genomic instability phenotypes. What underlies their wide-ranging effects on genome stability remains poorly understood. Here we combined biochemical and atomic force microscopy approaches with single molecule R-loop footprinting to demonstrate that R-loops formed at the model Airn locus in vitro adopt a defined set of three-dimensional conformations characterized by distinct shapes and volumes, which we call R-loop objects. Interestingly, we show that these R-loop objects impose specific physical constraints on the DNA, as revealed by the presence of stereotypical angles in the surrounding DNA. Biochemical probing and mutagenesis experiments revealed that the formation of R-loop objects at Airn is dictated by the extruded non-template strand, suggesting that R-loops possess intrinsic sequence-driven properties. Consistent with this, we show that R-loops formed at the fission yeast gene sum3 do not form detectable R-loop objects. Our results reveal that R-loops differ by their architectures and that the organization of the non-template strand is a fundamental characteristic of R-loops, which could explain that only a subset of R-loops is associated with replication-dependent DNA breaks.

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