Profile Reconstruction and Quantitative Detection of Planar Defects with Composite-mode Total Focusing Method (CTFM)

2021 ◽  
pp. 102518
Author(s):  
S.J. Jin ◽  
C.F. Liu ◽  
S.Q. Shi ◽  
L. Lin ◽  
Z.B. Luo
Keyword(s):  
Quantitative Detection ◽  
Planar Defects ◽  
Profile Reconstruction ◽  
Composite Mode

Generation of 4H and 6H Structures During the Hexagonal-Rhombohedral Transformation in Dy2Co17

1975 ◽  
Vol 33 ◽  
pp. 38-39
Author(s):  
C. W. Allen ◽  
D. L. Kuruzar
Keyword(s):  
Elevated Temperatures ◽  
Layer Structure ◽  
Transition Element ◽  
Temperature Structure ◽  
Allotropic Transformation ◽  
Layer Plane ◽  
Planar Defects ◽  
Topologically Close Packed ◽  
Transformation Mechanisms ◽  
Shear Transformation

The rare earth/transition element intermetallics R2T17 are essentially topologically close packed phases for which layer structure models have already been presented. Many of these compounds are known to undergo allotropic transformation of the type at elevated temperatures. It is not unexpected that shear transformation mechanisms are involved in view of the layering character of the structures. The transformations are evidently quite sluggish, illustrated in furnace cooled Dy2Co17 by the fact that only rarely has the low temperature rhombohedral form been seen. The more usual structures observed so far in furnace cooled alloys include 4H and 6H in Dy2Co17 (Figs. 1 and 2) . In any event it is quite clear that the general microstructure is very complicated as a consequence of the allotropy, illustrated in Fig. 3. Numerous planar defects in the layer plane orientation are evident as are non-layer plane defects inherited from a high temperature structure.

Planar defects in ordered (Ga,In)P

1988 ◽  
Vol 46 ◽  
pp. 902-903
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Diffraction ◽  
Vapor Phase ◽  
Growth Direction ◽  
High Density ◽  
Ordered Structure ◽  
Planar Defects ◽  
Diffraction Patterns ◽  
Ternary Semiconductors ◽  
Anion Species ◽  
Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

Point and planar defects in the iron sulfide compounds Fe1-xS

1984 ◽  
Vol 42 ◽  
pp. 434-435
Author(s):  
Thao A. Nguyen
Keyword(s):  
Low Temperatures ◽  
Direct Evidence ◽  
Iron Sulfide ◽  
Planar Defects ◽  
Selective Area ◽  
Vacancy Ordering ◽  
Different Types ◽  
Lattice Images ◽  
The Subject ◽  
Beam Lattice

It is well known that the large deviations from stoichiometry in iron sulfide compounds, Fe1-xS (0≤x≤0.125), are accommodated by iron vacancies which order and form superstructures at low temperatures. Although the ordering of the iron vacancies has been well established, the modes of vacancy ordering, hence superstructures, as a function of composition and temperature are still the subject of much controversy. This investigation gives direct evidence from many-beam lattice images of Fe1-xS that the 4C superstructure transforms into the 3C superstructure (Fig. 1) rather than the MC phase as previously suggested. Also observed are an intrinsic stacking fault in the sulfur sublattice and two different types of vacancy-ordering antiphase boundaries. Evidence from selective area optical diffractograms suggests that these planar defects complicate the diffraction pattern greatly.

Nano-probe x-ray analysis and high-resolution imaging on planar defects in high-pressure synthesized infinite-layer superconductor

1994 ◽  
Vol 52 ◽  
pp. 728-729
Author(s):  
Y. Y. Wang ◽  
H. Zhang ◽  
V. P. Dravid ◽  
H. Zhang ◽  
L. D. Marks ◽  
...  
Keyword(s):  
High Pressure ◽  
High Resolution ◽  
Atomic Structure ◽  
Emission Spectra ◽  
High Resolution Electron Microscopy ◽  
Planar Defects ◽  
X Ray ◽  
Infinite Layer ◽  
Resolution Electron ◽  
Resolution Imaging

Azuma et al. observed planar defects in a high pressure synthesized infinitelayer compound (i.e. ACuO2 (A=cation)), which exhibits superconductivity at ~110 K. It was proposed that the defects are cation deficient and that the superconductivity in this material is related to the planar defects. In this report, we present quantitative analysis of the planar defects utilizing nanometer probe xray microanalysis, high resolution electron microscopy, and image simulation to determine the chemical composition and atomic structure of the planar defects. We propose an atomic structure model for the planar defects.Infinite-layer samples with the nominal chemical formula, (Sr1-xCax)yCuO2 (x=0.3; y=0.9,1.0,1.1), were prepared using solid state synthesized low pressure forms of (Sr1-xCax)CuO2 with additions of CuO or (Sr1-xCax)2CuO3, followed by a high pressure treatment.Quantitative x-ray microanalysis, with a 1 nm probe, was performed using a cold field emission gun TEM (Hitachi HF-2000) equipped with an Oxford Pentafet thin-window x-ray detector. The probe was positioned on the planar defects, which has a 0.74 nm width, and x-ray emission spectra from the defects were compared with those obtained from vicinity regions.

Contrasts of planar defects in reflection electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 1004-1005
Author(s):  
Feng Tsai ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Surface Defects ◽  
Practical Importance ◽  
Theoretical Treatment ◽  
Crystal Surfaces ◽  
Planar Defects ◽  
Surface Steps ◽  
Surface Reconstructions ◽  
Domain Boundaries ◽  
Reflection Electron Microscopy

Reflection electron microscopy (REM) has been used to study surface defects such as surface steps, dislocations emerging on crystal surfaces, and surface reconstructions. However, only a few REM studies have been reported about the planar defects emerging on surfaces. The interaction of planar defects with surfaces may be of considerable practical importance but so far there seems to be only one relatively simple theoretical treatment of the REM contrast and very little experimental evidence to support its predications. Recently, intersections of both 90° and 180° ferroelectric domain boundaries with BaTiO3 crystal surfaces have been investigated by Tsai and Cowley with REM.The REM observations of several planar defects, such as stacking faults and domain boundaries have been continued by the present authors. All REM observations are performed on a JEM-2000FX transmission electron microscope. The sample preparations may be seen somewhere else. In REM, the incident electron beam strikes the surface of a crystal with a small glancing angle.

Reconstruction of complex shaped crack from ECT signals based on a fast forward solver using an advanced multi-media element

2020 ◽  
Vol 64 (1-4) ◽  
pp. 621-629
Author(s):  
Yingsong Zhao ◽  
Cherdpong Jomdecha ◽  
Shejuan Xie ◽  
Zhenmao Chen ◽  
Pan Qi ◽  
...  
Keyword(s):  
Coefficient Matrix ◽  
Crack Edge ◽  
Numerical Accuracy ◽  
Gauss Point ◽  
Current Testing ◽  
Efficient Simulation ◽  
Shaped Crack ◽  
Multi Media ◽  
Profile Reconstruction ◽  
Crack Profile

In this paper, the conventional database type fast forward solver for efficient simulation of eddy current testing (ECT) signals is upgraded by using an advanced multi-media finite element (MME) at the crack edge for treating inversion of complex shaped crack. Because the analysis domain is limited at the crack region, the fast forward solver can significantly improve the numerical accuracy and efficiency once the coefficient matrices of the MME can be properly calculated. Instead of the Gauss point classification, a new scheme to calculate the coefficient matrix of the MME is proposed and implemented to upgrade the ECT fast forward solver. To verify its efficiency and the feasibility for reconstruction of complex shaped crack, several cracks were reconstructed through inverse analysis using the new MME scheme. The numerical results proved that the upgraded fast forward solver can give better accuracy for simulating ECT signals, and consequently gives better crack profile reconstruction.

Therapeutic efficacy of some extracts of hot pepper fruits (Capsicum annuum) and Sumac seeds (Rhus coriaria) on the growth of some isolated dermatophytes species

2018 ◽  
Vol 1 (3) ◽  
pp. 52-62
Author(s):  
Sara Omran ◽  
Abdulghani Alsamarai ◽  
Firas Razzzaq
Keyword(s):  
Antifungal Activity ◽  
Fungal Infection ◽  
Aqueous Extract ◽  
Plant Extracts ◽  
Therapeutic Efficacy ◽  
Diffusion Method ◽  
Quantitative Detection ◽  
Hot Pepper ◽  
Alcoholic Extract ◽  
Dermatology Clinic

Background: Fungal infections are one of the common skin diseases with difficulty in their treatment approach. The present efficient drugs for fungal infection are limited. Aim: To determine the therapeutic efficacy of plant extracts as alternative antifungal agents. Materials and methods: 100 clinical samples [68 from female and 32 from male] were collected during the period from March to July 2017 from subjects attending Dermatology Clinic in Salah Uldean General Hospital. Fungal infection was diagnosed with using KOH wet preparation. Fungal species identified by using conventional approach. The active ingredients existing in the plant extracts were detected and analyzed through qualitative and quantitative detection technique of chemical compounds using a high performance liquid chromatographic device (HPLC). Agar diffusion method was used to determine antifungal activity of plant extracts. Results: Direct microscopic examination showed that there were (75%) positive samples, while culture shows (67%) positive samples. The isolated dermatophytes belong to Epidermophyoton, Microsporum, and Trichophyton genus. The predominant dermatophytes were T. rubrum (25%) species. The highest frequency of infection was in the age group of 11-20 years. The sensitivity of the tested fungi to the aqueous and alcoholic plant extracts varies. Alcoholic extract of the hot pepper plant was more effective as antifungal than the aqueous extract of the same plant. However, aqueous hot pepper extracts was more effective against T. mentagrophyte than that of alcoholic extract. Additionally, alcoholic Sumac extract shows higher efficacy that aqueous extract. Conclusion: Hot pepper and Sumac extracts show antifungal activity against Microsporum canis, Trichophyton rubrum and T. mentagrophyte.

Quantitative detection and imaging of soot particles by laser induced incandescence

1997 ◽  
Author(s):  
K. McManus ◽  
M. Allen ◽  
W. Rawlins ◽  
K. McManus ◽  
M. Allen ◽  
...  
Keyword(s):  
Quantitative Detection ◽  
Soot Particles ◽  
Laser Induced Incandescence
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