scholarly journals Quantum confinement and dielectric profiles of colloidal nanoplatelets of halide inorganic and hybrid organic–inorganic perovskites

Nanoscale ◽  
2016 ◽  
Vol 8 (12) ◽  
pp. 6369-6378 ◽  
Author(s):  
Daniel Sapori ◽  
Mikaël Kepenekian ◽  
Laurent Pedesseau ◽  
Claudine Katan ◽  
Jacky Even
Keyword(s):  
High Frequency ◽  
Quantum Confinement ◽  
Three Dimensional ◽  
Two Dimensional ◽  
3D Structures

Quantum confinement as well as high frequencyε∞and staticεsdielectric profiles are described for nanoplatelets of halide inorganic perovskites CsPbX3(X = I, Br, Cl) and hybrid organic–inorganic perovskites (HOP) in two-dimensional (2D) and three-dimensional (3D) structures.

scholarly journals Early Detection of Fetal Abnormality

2013 ◽  
Vol 7 (1) ◽  
pp. 46-50
Author(s):  
Ritsuko K Pooh
Keyword(s):  
Early Detection ◽  
High Frequency ◽  
Obstet Gynecol ◽  
Three Dimensional ◽  
First Trimester ◽  
Two Dimensional ◽  
Fetal Abnormality ◽  
Fetal Abnormalities ◽  
Comprehensive Information ◽  
Vaginal Transducer

ABSTRACT After introduction of high-frequency vaginal transducer, transvaginal two-dimensional ultrasound has established a field of sonoembryology and most of the major fetal abnormalities have been detectable in the first trimester. Three-dimensional ultrasound adds an objective and comprehensive information to two-dimensional sonographic findings. How to cite this article Pooh RK. Early Detection of Fetal Abnormality. Donald School J Ultrasound Obstet Gynecol 2013;7(1):46-50.

scholarly journals Tapered elasticæ as a route for axisymmetric morphing structures

Soft Matter ◽  
2020 ◽  
Vol 16 (33) ◽  
pp. 7739-7750
Author(s):  
Mingchao Liu ◽  
Lucie Domino ◽  
Dominic Vella
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
3D Structures

Transforming flat two-dimensional (2D) sheets into three-dimensional (3D) structures by a combination of careful cutting and applied loads is an emerging manufacturing paradigm; we study how to design the cut pattern to obtain a desired 3D structure.

On the spatio-temporal stability of primary and secondary crossflow vortices in a three-dimensional boundary layer

2002 ◽  
Vol 456 ◽  
pp. 85-111 ◽  
Author(s):  
WERNER KOCH
Keyword(s):  
Saddle Point ◽  
High Frequency ◽  
Wave Packets ◽  
Temporal Stability ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Boundary ◽  
Spatio Temporal ◽  
Secondary Instabilities ◽  
Dimensional Wave

To examine possible links between a global instability and laminar–turbulent breakdown in a three-dimensional boundary layer, the spatio-temporal stability of primary and secondary crossflow vortices has been investigated for the DLR swept-plate experiment. In the absence of any available procedure for the direct verification of pinching for three-dimensional wave packets the alternative saddle-point continuation method has been applied. This procedure is known to give reliable results only in a certain vicinity of the most unstable ray. Therefore, finding no absolute instability by this method does not prove that the flow is absolutely stable. Accordingly, our results obtained this way need to be confirmed experimentally or by numerical simulations. A geometric interpretation of the time-asymptotic saddle-point result explains certain convergence and continuation problems encountered in the numerical wave packet analysis. Similar to previous results, all our three-dimensional wave packets for primary crossflow vortices were found to be convectively unstable.Due to prohibitive CPU time requirements the existing procedure for the verification of pinching for two-dimensional wave packets of secondary high-frequency instabilities could not be implemented. Again saddle-point continuation was used. Surprisingly, all two-dimensional wave packets of high-frequency secondary instabilities investigated were also found to be convectively unstable. This finding was corroborated by recent spatial direct numerical simulations of Wassermann & Kloker (2001) for a similar problem. This suggests that laminar–turbulent breakdown occurs after the high-frequency secondary instabilities enter the nonlinear stage, and spatial marching techniques, such as the parabolized stability equation method, should be applicable for the computation of these nonlinear states.

Transition from Two-Dimensional to Three-Dimensional Quantum Confinement in Semiconductor Quantum Wires/Quantum Dots

Nano Letters ◽  
2007 ◽  
Vol 7 (8) ◽  
pp. 2227-2233 ◽  
Author(s):  
Q. Zhu ◽  
K. F. Karlsson ◽  
E. Pelucchi ◽  
E. Kapon
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Quantum Wires ◽  
Three Dimensional ◽  
Two Dimensional

scholarly journals Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shota Ono
Keyword(s):  
Crystal Structures ◽  
Three Dimensional ◽  
Building Blocks ◽  
Two Dimensional ◽  
3D Structures ◽  
Metallic Element ◽  
Computational Materials ◽  
Dynamics Simulations ◽  
Dimensional Crystal

AbstractSome of the three-dimensional (3D) crystal structures are constructed by stacking two-dimensional (2D) layers. To study whether this geometric concept, i.e., using 2D layers as building blocks for 3D structures, can be applied to computational materials design, we theoretically investigate the dynamical stability of copper-based compounds CuX (a metallic element X) in the B$$_h$$ h and L1$$_1$$ 1 structures constructed from the buckled honeycomb (BHC) structure and in the B2 and L1$$_0$$ 0 structures constructed from the buckled square (BSQ) structure. We demonstrate that (i) if CuX in the BHC structure is dynamically stable, those in the B$$_h$$ h and L1$$_1$$ 1 structures are also stable. Using molecular dynamics simulations, we particularly show that CuAu in the B$$_h$$ h and L1$$_1$$ 1 structures withstand temperatures as high as 1000 K. Although the interrelationship of the metastability between the BSQ and the 3D structures (B2 and L1$$_0$$ 0 ) is not clear, we find that (ii) if CuX in the B2 (L1$$_0$$ 0 ) structure is dynamically stable, that in the L1$$_0$$ 0 (B2) is unstable. This is rationalized by the tetragonal Bain path calculations.

scholarly journals ICONICITY AND VISUAL REPRESENTATIONS IN CHILDRENS’ NARRATIVE

2020 ◽  
pp. 78-106
Author(s):  
Maria Mertzani
Keyword(s):  
Sign Language ◽  
High Frequency ◽  
Mental Representations ◽  
Three Dimensional ◽  
Visual Representations ◽  
Visual Image ◽  
Two Dimensional ◽  
High Activation ◽  
Sign Languages ◽  
Two Dimensional Image

The study examines the creation of a childrens’ visual book based on the reading of an indigenous text story. In particular, it demonstrates that the ratio of labial versus nasal sounds in a text predicts a difference in its meanings, as it is perceived by its readers, signers and non-signers. Texts that have a relatively high frequency of labial sounds are more likely to express high activation, whereas a relatively high frequency of nasal sounds indicates a low activation. These sounds seem to relate to specific mental representations, which are mapped to particular handshapes across sign languages. Thus, the study suggests that the higher frequency of specific phonemes may connect to certain signed representations, which the design of children’s picturebook can take into consideration, since the two- dimensional image can relate to the three-dimensional materialisation of SLs and their constructs. Keywords: picturebook, visual image, Sign Language, indigenous narrative, iconicity.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

A linearity test for thick specimens imaged by HVEM over a 180° angular range

1991 ◽  
Vol 49 ◽  
pp. 552-553
Author(s):  
Yu Liu
Keyword(s):  
Phase Contrast ◽  
Three Dimensional ◽  
Angular Range ◽  
Two Dimensional ◽  
Back Projection ◽  
Line Integral ◽  
Exponential Law ◽  
Transmission Electron ◽  
Absorption Law ◽  
Linearity Test

The image obtained in a transmission electron microscope is the two-dimensional projection of a three-dimensional (3D) object. The 3D reconstruction of the object can be calculated from a series of projections by back-projection, but this algorithm assumes that the image is linearly related to a line integral of the object function. However, there are two kinds of contrast in electron microscopy, scattering and phase contrast, of which only the latter is linear with the optical density (OD) in the micrograph. Therefore the OD can be used as a measure of the projection only for thin specimens where phase contrast dominates the image. For thick specimens, where scattering contrast predominates, an exponential absorption law holds, and a logarithm of OD must be used. However, for large thicknesses, the simple exponential law might break down due to multiple and inelastic scattering.

An Image Reconstruction System Applied to High Voltage Microscopy

1975 ◽  
Vol 33 ◽  
pp. 292-293
Author(s):  
D. E. Johnson
Keyword(s):  
High Voltage ◽  
Prior Information ◽  
Block Diagram ◽  
Three Dimensional ◽  
Real Space ◽  
Two Dimensional ◽  
Efficient Manner ◽  
Fourier Methods ◽  
Tilt Series ◽  
Methods Of Reconstruction

Increased specimen penetration; the principle advantage of high voltage microscopy, is accompanied by an increased need to utilize information on three dimensional specimen structure available in the form of two dimensional projections (i.e. micrographs). We are engaged in a program to develop methods which allow the maximum use of information contained in a through tilt series of micrographs to determine three dimensional speciman structure.In general, we are dealing with structures lacking in symmetry and with projections available from only a limited span of angles (±60°). For these reasons, we must make maximum use of any prior information available about the specimen. To do this in the most efficient manner, we have concentrated on iterative, real space methods rather than Fourier methods of reconstruction. The particular iterative algorithm we have developed is given in detail in ref. 3. A block diagram of the complete reconstruction system is shown in fig. 1.

Sign in / Sign up

Export Citation Format

Share Document