scholarly journals Simulating Boundary Region Plasma Instabilities.

2021 ◽  
Author(s):  
Lucas Beving ◽  
Matthew Hopkins ◽  
Scott Baalrud
Keyword(s):  
Boundary Region ◽  
Plasma Instabilities ◽  
Region Plasma

scholarly journals Spectral fluctuation analysis of ionospheric inhomogeneities over Brazilian territory Part II: E-F valley region plasma instabilities

2019 ◽  
Vol 64 (8) ◽  
pp. 1592-1599 ◽  
Author(s):  
J. Neelakshi ◽  
Reinaldo R. Rosa ◽  
Siomel Savio ◽  
Francisco C. de Meneses ◽  
Stephan Stephany ◽  
...  
Keyword(s):  
Fluctuation Analysis ◽  
Plasma Instabilities ◽  
Region Plasma

The Effect of Specimen Thickness and Probe Size on Aem Analysis of Cr-Depletion Profiles in Sensitized Stainless Steel

1982 ◽  
Vol 40 ◽  
pp. 518-519
Author(s):  
E. L. Hall
Keyword(s):  
Grain Boundaries ◽  
Boundary Region ◽  
Chromium Concentration ◽  
Foil Thickness ◽  
Specimen Thickness ◽  
Probe Size ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Sensitization Process ◽  
Compositional Gradients

Sensitization in stainless steels is caused by the formation of chromium-rich M23C6 carbides at grain boundaries, which depletes the adjacent matrix and boundary region of chromium, and hence leads to rapid intergranular attack. To fully understand the sensitization process, and to test the accuracy of theories proposed to model this process, it is necessary to obtain very accurate measurements of the chromium concentration at grain boundaries in sensitized specimens. Quantitative X-ray spectroscopy in the analytical electron microscope (AEM) enables the chromium concentration profile across these boundaries to be studied directly; however, it has been shown that a strong effect of foil thickness and electron probe size may be present in the analysis of rapidly-changing compositional gradients. The goal of this work is to examine these effects.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

2D carrier Density Mapping Using SNDM-dC/dV and dC/dz of SiC Power MOSFET

2019 ◽  
Author(s):  
Jing-jiang Yu ◽  
T. Yamaoka ◽  
T. Aiso ◽  
K. Watanabe ◽  
Y. Shikakura ◽  
...  
Keyword(s):  
Carrier Density ◽  
Environmental Control ◽  
Boundary Region ◽  
Power Mosfet ◽  
Dopant Profiling ◽  
Density Mapping ◽  
Resolution Observation ◽  
Develop Software ◽  
20 Nm ◽  
High Resolution Observation

Abstract Scanning nonlinear dielectric microscopy is continuously developed as an AFM-derived method for 2D dopant profiling of semiconductor devices. In this paper, the authors apply 2D carrier density mapping to Si and SiC and succeed a high resolution observation of the SiC planar power MOSFET. Furthermore, they develop software that combines dC/dV and dC/dz images and expresses both density and polarity in a single distribution image. The discussion provides the details of AFM experiments that were conducted using a Hitachi environmental control AFM5300E system. The results indicated that the carrier density decreases in the boundary region between n plus source and p body. The authors conclude that although the resolutions of dC/dV and dC/dz are estimated to be 20 nm or less and 30 nm or less, respectively, there is a possibility that the resolution can be further improved by using a sharpened probe.

scholarly journals Vp/Vs tomography in the southern California plate boundary region using body and surface wave traveltime data

2018 ◽  
Vol 216 (1) ◽  
pp. 609-620 ◽  
Author(s):  
Hongjian Fang ◽  
Huajian Yao ◽  
Haijiang Zhang ◽  
Clifford Thurber ◽  
Yehuda Ben-Zion ◽  
...  
Keyword(s):  
Surface Wave ◽  
Southern California ◽  
Plate Boundary ◽  
Boundary Region

scholarly journals Decratonization by rifting enables orogenic reworking and transcurrent dispersal of old terranes in NE Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carlos E. Ganade ◽  
Roberto F. Weinberg ◽  
Fabricio A. Caxito ◽  
Leonardo B. L. Lopes ◽  
Lucas R. Tesser ◽  
...  
Keyword(s):  
Shear Zones ◽  
Boundary Region ◽  
The North ◽  
Pan African ◽  
Juvenile Material ◽  
Oceanic Basin ◽  
Borborema Province ◽  
Isotopic Model ◽  
Late Neoproterozoic

AbstractDispersion and deformation of cratonic fragments within orogens require weakening of the craton margins in a process of decratonization. The orogenic Borborema Province, in NE Brazil, is one of several Brasiliano/Pan-African late Neoproterozoic orogens that led to the amalgamation of Gondwana. A common feature of these orogens is that a period of extension and opening of narrow oceans preceded inversion and collision. For the case of the Borborema Province, the São Francisco Craton was pulled away from its other half, the Benino-Nigerian Shield, during an intermittent extension event between 1.0–0.92 and 0.9–0.82 Ga. This was followed by inversion of an embryonic and confined oceanic basin at ca. 0.60 Ga and transpressional orogeny from ca. 0.59 Ga onwards. Here we investigate the boundary region between the north São Francisco Craton and the Borborema Province and demonstrate how cratonic blocks became physically involved in the orogeny. We combine these results with a wide compilation of U–Pb and Nd-isotopic model ages to show that the Borborema Province consists of up to 65% of strongly sheared ancient rocks affiliated with the São Francisco/Benino-Nigerian Craton, separated by major transcurrent shear zones, with only ≈ 15% addition of juvenile material during the Neoproterozoic orogeny. This evolution is repeated across a number of Brasiliano/Pan-African orogens, with significant local variations, and indicate that extension weakened cratonic regions in a process of decratonization that prepared them for involvement in the orogenies, that led to the amalgamation of Gondwana.

scholarly journals Fuzzy Covering-Based Three-Way Clustering

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Dandan Yang
Keyword(s):  
Nearest Neighbor ◽  
Structural Information ◽  
Boundary Region ◽  
Global Perspective ◽  
Semantic Interpretation ◽  
Entropy Theory ◽  
Fuzzy Similarity ◽  
Fuzzy Similarity Relation ◽  
The Universe ◽  
Better Than

This paper investigates the three-way clustering involving fuzzy covering, thresholds acquisition, and boundary region processing. First of all, a valid fuzzy covering of the universe is constructed on the basis of an appropriate fuzzy similarity relation, which helps capture the structural information and the internal connections of the dataset from the global perspective. Due to the advantages of valid fuzzy covering, we explore the valid fuzzy covering instead of the raw dataset for RFCM algorithm-based three-way clustering. Subsequently, from the perspective of semantic interpretation of balancing the uncertainty changes in fuzzy sets, a method of partition thresholds acquisition combining linear and nonlinear fuzzy entropy theory is proposed. Furthermore, boundary regions in three-way clustering correspond to the abstaining decisions and generate uncertain rules. In order to improve the classification accuracy, the k-nearest neighbor (kNN) algorithm is utilized to reduce the objects in the boundary regions. The experimental results show that the performance of the proposed three-way clustering based on fuzzy covering and kNN-FRFCM algorithm is better than the compared algorithms in most cases.

Pressure Waves in Microscopic Simulations of Laser Ablation Leonid

1998 ◽  
Vol 538 ◽  
Author(s):  
V. Zhigilei ◽  
Barbara J. Garrison
Keyword(s):  
Boundary Condition ◽  
Laser Ablation ◽  
Laser Energy ◽  
Scale Up ◽  
Boundary Region ◽  
Dynamics Simulation ◽  
Pressure Waves ◽  
Absorption Region ◽  
Organic Solids ◽  
Direct Laser

AbstractLaser ablation of organic solids is a complex collective phenomenon that includes processes occurring at different length and time scales. A mesoscopic breathing sphere model developed recently for molecular dynamics simulation of laser ablation and damage of organic solids has significantly expanded the length-scale (up to hundreds of nanometers) and the time-scale (up to nanoseconds) of the simulations. The laser induced buildup of a high pressure within the absorbing volume and generation of the pressure waves propagating from the absorption region poses an additional challenge for molecular-level simulation. A new dynamic boundary condition is developed to minimize the effects of the reflection of the wave from the boundary of the computational cell. The boundary condition accounts for the laser induced pressure wave propagation as well as the direct laser energy deposition in the boundary region.

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