Determination of Size Distribution of Elliptical Microvessels from Size Distribution Measurement of Their Section Profiles

2003 ◽  
Vol 228 (1) ◽  
pp. 84-92 ◽  
Author(s):  
R.A. Krasnoperov ◽  
A.N. Gerasimov
Keyword(s):  
Size Distribution ◽  
Three Dimensional ◽  
Axial Ratio ◽  
Minor Radius ◽  
Transmission Electron ◽  
Section Profile ◽  
Ultrathin Sections ◽  
The One ◽  
Major Radius

In transmission electron microscopy, microvessels (MVs) are studied as profiles on ultrathin sections. To determine MV sizes from measurements made on MV profiles, an assumption must be made about MV shape, a circular cylinder being used to approximate the latter on limited lengths. However, this model is irrelevant in case MVs have some flatness. The elliptical cylinder model is preferable, although relationships between the cylinder profile (two-dimensional; 2D) and its true (three-dimensional; 3D) sizes are not yet known. We have obtained the 2D/3D functions that express the relationships between such profile sizes as the minor radius (Y), major radius (X), axial ratio (X/Y), area (S), and perimeter (P) on the one hand, and the corresponding MV sizes (Y0, X0, X0/Y0, S0, and P0) on the other. The 2D/3D functions make it possible to derive elliptical MV sizes from section profile size distributions, probability density functions (PDFs) for the latter being determined. We have applied the 2D/3D functions in studying axial ratios of thyroid hemocapillaries. A factual X/Y frequency histogram has been constructed and fitted by theoretical X/Y PDFs plotted for different sets of capillary sizes. The thyroid capillaries have been revealed to be clustered, 72.7% of them having X0/Y0 ≈ 1.6, 17.6%, X0/Y0 ≈ 1.0. and 9.7%, X0/Y0 ≈ 3.2. The proposed technique is instrumental in precise modeling of microclrculatory network geometry.

scholarly journals Meso-Scale Transmission Electron Microscope Tomography Applied for Wax Distribution in Toner Particles

2013 ◽  
Vol 19 (S5) ◽  
pp. 58-61 ◽  
Author(s):  
Mino Yang ◽  
Jun-Ho Lee ◽  
Hee-Goo Kim ◽  
Euna Kim ◽  
Young-Nam Kwon ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Three Dimensional ◽  
Chromatic Aberration ◽  
Laser Printer ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Z Contrast ◽  
Contrast Image

AbstractDistribution of wax in laser printer toner was observed using an ultra-high-voltage (UHV) and a medium-voltage transmission electron microscope (TEM). As the radius of the wax spans a hundred to greater than a thousand nanometers, its three-dimensional recognition via TEM requires large depth of focus (DOF) for a volumetric specimen. A tomogram with a series of the captured images would allow the determination of their spatial distribution. In this study, bright-field (BF) images acquired with UHV-TEM at a high tilt angle prevented the construction of the tomogram. Conversely, the Z-contrast images acquired by the medium-voltage TEM produced a successful tomogram. The spatial resolution for both is discussed, illustrating that the image degradation was primarily caused by beam divergence of the Z-contrast image and the combination of DOF and chromatic aberration of the BF image from the UHV-TEM.

High-Efficiency Three-Dimensional Visualization of Complex Microstructures via Multidimensional STEM Acquisition and Reconstruction

2020 ◽  
Vol 26 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Kevin G. Field ◽  
Benjamin P. Eftink ◽  
Chad M. Parish ◽  
Stuart A. Maloy
Keyword(s):  
High Efficiency ◽  
3D Visualization ◽  
Accurate Determination ◽  
Three Dimensional ◽  
High Energy ◽  
Scanning Transmission Electron Microscope ◽  
Chromium Steel ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractComplex material systems in which microstructure and microchemistry are nonuniformly dispersed require three-dimensional (3D) rendering(s) to provide an accurate determination of the physio-chemical nature of the system. Current scanning transmission electron microscope (STEM)-based tomography techniques enable 3D visualization but can be time-consuming, so only select systems or regions are analyzed in this manner. Here, it is presented that through high-efficiency multidimensional STEM acquisition and reconstruction, complex point cloud-like microstructural features can quickly and effectively be reconstructed in 3D. The proposed set of techniques is demonstrated, analyzed, and verified for a high-chromium steel with heterogeneously situated features induced using high-energy neutron bombardment.

Synthesis of Layered Titanate Micro/nano-materials for Efficient Pollutant Treatment in Aqueous Media

2011 ◽  
Vol 1309 ◽  
Author(s):  
Y. X. Tang ◽  
Y. K. Lai ◽  
D. G. Gong ◽  
Zhili Dong ◽  
Z. Chen
Keyword(s):  
Aqueous Media ◽  
Three Dimensional ◽  
High Specific Surface Area ◽  
Nano Materials ◽  
Raman Scattering Spectroscopy ◽  
Micro Particles ◽  
Transmission Electron ◽  
Composition And Structure ◽  
Layered Titanate ◽  
The One

ABSTRACTIn this work, the one dimensional (1D) titanate nanotubes (TNT)/nanowires (TNW), bulk titanate micro-particles (TMP), and three dimensional (3D) titanate microsphere particles (TMS) with high specific surface area were synthesized via different approaches. The chemical composition and structure of these products have been characterized by field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM) study and Raman scattering spectroscopy. The as-prepared TMS shows excellent adsorption performance compared with TMP, TNW and TNT when methylene blue (MB) and PbII ions are used as representative organic and inorganic pollutants.

scholarly journals H3PW12O40 Anchored on the Three-Dimensional and Networked SBA-15 as an Efficient and Recyclable Catalyst for Mannich Reaction

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Tengfei Zhang ◽  
Wei Zhang ◽  
Hao Dong ◽  
Qing Liu
Keyword(s):  
Mannich Reaction ◽  
Three Dimensional ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
One Pot ◽  
Solvent Free Condition ◽  
Transmission Electron ◽  
Ft Ir ◽  
The One

Abstract. The three-dimensional and networked SBA-15 (3D-SBA-15) supported phosphotungstic acid (PW) was used as heterogeneous catalyst for the one-pot three-components Mannich reaction at room temperature. The H3PW12O40/3D-SBA-15 catalyst was prepared using an impregnation method and confirmed by series of characterizations such as Fourier-transform infrared spectra (FT-IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 physisorption and thermogravimetric (TG) analysis. 50PW/3D-SBA-15 catalyst with H3PW12O40 loading of 50 wt% showed the highest yield of 93% in 1.8 h for the Mannich reaction of benzaldehyde, aniline and acetophenone under solvent-free condition. A series of β-aminoketone derivatives were synthesized successfully in the presence of this catalyst. In addition, H3PW12O40/3D-SBA-15 catalyst can be easily recovered and reused four times without significant decrease of the activity. This work provides an improved modification of the three-component Mannich reaction in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst and a simple workup procedure.                                                Resumen.  El ácido fosfotungstico (PW) se soportó en sílice SBA-15 (3D-SBA-15) y se usó como catalizador heterogéneo en la reacción de Mannich en un solo paso de tres componentes a temperatura ambiente. El catalizador H3PW12O40/3D-SBA-15 se preparó mediante impregnación y se caracterizó por espectroscopia de infrarrojo (FT-IR), microscopia electrónica de barrido (SEM), microscopía electrónica de transmisión (TEM), difracción de rayos-X (XRD), fisisorción de N2 y análisis termogravimétrico (TG). El catalizador 50PW/3D-SBA-15, con una carga de H3PW12O40 del 50% en peso, mostró el rendimiento más alto del 93% en 1.8 h para la reacción de Mannich entre benzaldehído, anilina y acetofenona, sin disolvente. Se sintetizó una serie de derivados de β-aminocetona en presencia de este catalizador. Además, el catalizador H3PW12O40/3D-SBA-15 puede recuperarse fácilmente y reutilizarse cuatro veces sin pérdida significativa de la actividad. Este trabajo reporta una modificación de la reacción de Mannich de tres componentes bajo condiciones de reacción suaves, perfiles de reacción limpios, pequeña cantidad de catalizador y un procedimiento de tratamiento simple.

An Integrated System for Transmission Electron Microscopy.

2000 ◽  
Vol 6 (S2) ◽  
pp. 280-281
Author(s):  
B. Carragher ◽  
N. Kisseberth ◽  
D. Kriegman ◽  
R.A. Milligan ◽  
C.S. Potter ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Biology ◽  
Three Dimensional ◽  
Digital Camera ◽  
Integrated System ◽  
Macromolecular Assemblies ◽  
Integrative Research ◽  
Transmission Electron ◽  
Electron Density Map

Macromolecular microscopy is becoming an increasingly important tool for structural biology. The development of improved capabilities for three-dimensional electron microscopy is critical for optimal progress in emerging integrative research in molecular cell biology. These techniques currently suffer from several severe disadvantages related to the tremendous time and effort required to acquire and analyze the data.For several years we have been developing software for automated and intelligent acquisition of transmission electron micrographs [1,2,3]. Our overall goal is to develop a system for rapid and routine structure determination of macromolecular assemblies from specimens preserved in vitreous ice. Ultimately we plan to develop an integrated system that can produce an electron density map of a structure within a few hours of inserting a specimen into the electron microscope. With this goal in mind it is essential that the images be acquired using a digital camera rather than film.

Determination of Size Distribution of Dispersed Nanophases and Spaces among them in PVC/MBS Blends by TEM Image Analysis

2011 ◽  
Vol 694 ◽  
pp. 399-402
Author(s):  
Zhen Yu Liu ◽  
Hong Tao Li ◽  
Feng Fu Yin ◽  
Yu Xiang Li ◽  
Yuan Zhang Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Image Analysis ◽  
Size Distribution ◽  
Quantitative Method ◽  
Rubber Blends ◽  
Transmission Electron

The size of dispersed nanophases and spaces among them are important factors effeted on toughness of plastic-rubber blends. In order to determine the size distribution of dispersed nanophases and spaces among them, a quantitative method was established by image analysis and transmission electron microscopy of ultra-thin PVC/MBS slices stained by OsO4. Two PVC/MBS blends samples were determined.

scholarly journals The stability and nonlinear evolution of quasi-geostrophic toroidal vortices

2019 ◽  
Vol 863 ◽  
pp. 60-78 ◽  
Author(s):  
Jean N. Reinaud ◽  
David G. Dritschel
Keyword(s):  
Nonlinear Evolution ◽  
Three Dimensional ◽  
Azimuthal Mode ◽  
Stability Properties ◽  
Central Vortex ◽  
Minor Radius ◽  
Toroidal Vortices ◽  
The Stability ◽  
Major Radius ◽  
Vortex Array

We investigate the linear stability and nonlinear evolution of a three-dimensional toroidal vortex of uniform potential vorticity under the quasi-geostrophic approximation. The torus can undergo a primary instability leading to the formation of a circular array of vortices, whose radius is approximately the same as the major radius of the torus. This occurs for azimuthal instability mode numbers $m\geqslant 3$, on sufficiently thin tori. The number of vortices corresponds to the azimuthal mode number of the most unstable mode growing on the torus. This value of $m$ depends on the ratio of the torus’ major radius to its minor radius, with thin tori favouring high mode $m$ values. The resulting array is stable when $m=4$ and $m=5$ and unstable when $m=3$ and $m\geqslant 6$. When $m=3$ the array has barely formed before it collapses towards its centre with the ejection of filamentary debris. When $m=6$ the vortices exhibit oscillatory staggering, and when $m\geqslant 7$ they exhibit irregular staggering followed by substantial vortex migration, e.g. of one vortex to the centre when $m=7$. We also investigate the effect of an additional vortex located at the centre of the torus. This vortex alters the stability properties of the torus as well as the stability properties of the circular vortex array formed from the primary toroidal instability. We show that a like-signed central vortex may stabilise a circular $m$-vortex array with $m\geqslant 6$.

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