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.

Many-Beam Lattice Images from Thicker Crystals

1978 ◽  
Vol 36 (3) ◽  
pp. 130-139
Author(s):  
S. Iijima
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Complex Oxides ◽  
Crystal Defects ◽  
Planar Defects ◽  
Transmission Electron ◽  
Lattice Images ◽  
The Many ◽  
Atom Configuration ◽  
Beam Lattice

Nearly a decade ago, the usefulness of lattice images for studying crystal defects was reported by Allpress et al. (1969). They analyzed abnormally spaced lattice fringes of crystals of the complex oxides and derived successfully the nature of planar defects occurring on a unit cell scale. Since then the method for studying atom configuration in crystals using high resolution transmission electron microscopy (HRTEM) has been investigated extensively. The studies have involved theoretical calculation of the many-beam lattice images of perfect crystals and applications of the method to solve problems in materials science.

The Defect Structures of Fe9S10

1983 ◽  
Vol 31 ◽  
Author(s):  
Thao A. Nguyen ◽  
Linn W. Hobbs
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stacking Faults ◽  
Defect Structures ◽  
Transmission Electron ◽  
Vacancy Ordering ◽  
Different Types ◽  
Lattice Images ◽  
Antiphase Domains ◽  
Complex Features

ABSTRACTThe defect structures of Fe9S10 have been studied by high-resolution transmission electron microscopy. Lattice images of the 3C and 4C superstructures and at least one other phase, which has not been previously reported, were observed. It has been found that the 4C superstructure transforms into the 3C superstructure rather than the MC phase as previously suggested. Intrinsic stacking faults in the sulfur sublattice and two different types of vacancy-ordering antiphase domains were also observed. Evidence from optical diffratograms of areas containing these defects suggests that complex features in the electron diffraction pattern may be artifactual.

High-Resolution Observation of Twinning in Fe1-XS Crystals

1985 ◽  
Vol 43 ◽  
pp. 224-225 ◽  
Author(s):  
Thao A. Nguyen ◽  
Linn W. Hobbs ◽  
Peter R. Buseck
Keyword(s):  
High Resolution ◽  
Iron Sulfide ◽  
Optical Parameters ◽  
Planar Defects ◽  
Electrical And Magnetic Properties ◽  
Transmission Electron ◽  
Resolution Observation ◽  
Half Angle ◽  
Lattice Images

The ordering of iron vacancies in highly nonstoichiometric iron sulfide compounds (Fe1-xS, 0 ⩽ x ⩽ 0.125) at temperature below 425K give rise to at least two different superstructures and a number of possible planar defect configurations. These ordered iron vacancies and associated planar defects are believed to influence greatly the electrical and magnetic properties of Fe1-xS crystals. Extensive efforts, employing high resolution transmission electron microscopy, to characterize the ordering of iron vacancies and associated planar defects have been carried out by Nguyen and Hobbs, Pierce and Buseck, and Nakazawa, et al. In this paper we report the characterization of twin boundaries in iron sulfide crystal of composition nominally Fe9S10.Many beam lattice images of crushed synthetic Fe9S10 crystals were obtained in a top-entry JEM 200CX transmission electron microscope. Relevant electron optical parameters were Cs = 1.2mm; divergence half-angle α = 0.5mrad; and an objective aperture which allowed electron beams up to 5nm-1 to contribute to the final image.

7-beam lattice images of (110) oriented Ge

1978 ◽  
Vol 36 (1) ◽  
pp. 290-291
Author(s):  
J.R. Parsons ◽  
C.W. Hoelke
Keyword(s):  
Image Features ◽  
Objective Lens ◽  
Lattice Plane ◽  
Lattice Image ◽  
Crystalline Defects ◽  
Transmission Electron ◽  
Lattice Images ◽  
Electron Microscopes ◽  
Structural Aspects ◽  
Beam Lattice

The direct imaging of a crystal lattice has intrigued electron microscopists for many years. What is of interest, of course, is the way in which defects perturb their atomic regularity. There are problems, however, when one wishes to relate aperiodic image features to structural aspects of crystalline defects. If the defect is inclined to the foil plane and if, as is the case with present 100 kV transmission electron microscopes, the objective lens is not perfect, then terminating fringes and fringe bending seen in the image cannot be related in a simple way to lattice plane geometry in the specimen (1).The purpose of the present work was to devise an experimental test which could be used to confirm, or not, the existence of a one-to-one correspondence between lattice image and specimen structure over the desired range of specimen spacings. Through a study of computed images the following test emerged.

Calculation of structure images of crystalline defects

1978 ◽  
Vol 36 (1) ◽  
pp. 282-283
Author(s):  
M.A. O'Keefe ◽  
Sumio Iijima
Keyword(s):  
Diffuse Scattering ◽  
Computing Time ◽  
Continuous Distribution ◽  
Sampling Interval ◽  
Reciprocal Space ◽  
Objective Lens ◽  
Lattice Images ◽  
Slice Method ◽  
Space Cell ◽  
Beam Lattice

We have extended the multi-slice method of computating many-beam lattice images of perfect crystals to calculations for imperfect crystals using the artificial superlattice approach. Electron waves scattered from faulted regions of crystals are distributed continuously in reciprocal space, and all these waves interact dynamically with each other to give diffuse scattering patterns.In the computation, this continuous distribution can be sampled only at a finite number of regularly spaced points in reciprocal space, and thus finer sampling gives an improved approximation. The larger cell also allows us to defocus the objective lens further before adjacent defect images overlap, producing spurious computational Fourier images. However, smaller cells allow us to sample the direct space cell more finely; since the two-dimensional arrays in our program are limited to 128X128 and the sampling interval shoud be less than 1/2Å (and preferably only 1/4Å), superlattice sizes are limited to 40 to 60Å. Apart from finding a compromis superlattice cell size, computing time must be conserved.

Geological Field Sketches and Illustrations

2019 ◽  
Author(s):  
Matthew J. Genge
Keyword(s):  
Cross Sections ◽  
Earth Science ◽  
Three Dimensional ◽  
Worked Examples ◽  
Scientific Publications ◽  
Thin Sections ◽  
Geological Features ◽  
Different Types ◽  
The Subject

Drawings, illustrations, and field sketches play an important role in Earth Science since they are used to record field observations, develop interpretations, and communicate results in reports and scientific publications. Drawing geology in the field furthermore facilitates observation and maximizes the value of fieldwork. Every geologist, whether a student, academic, professional, or amateur enthusiast, will benefit from the ability to draw geological features accurately. This book describes how and what to draw in geology. Essential drawing techniques, together with practical advice in creating high quality diagrams, are described the opening chapters. How to draw different types of geology, including faults, folds, metamorphic rocks, sedimentary rocks, igneous rocks, and fossils, are the subjects of separate chapters, and include descriptions of what are the important features to draw and describe. Different types of sketch, such as drawings of three-dimensional outcrops, landscapes, thin-sections, and hand-specimens of rocks, crystals, and minerals, are discussed. The methods used to create technical diagrams such as geological maps and cross-sections are also covered. Finally, modern techniques in the acquisition and recording of field data, including photogrammetry and aerial surveys, and digital methods of illustration, are the subject of the final chapter of the book. Throughout, worked examples of field sketches and illustrations are provided as well as descriptions of the common mistakes to be avoided.

Many-beam lattice images calculated at 100 kV and 1000 kV

1980 ◽  
Vol 36 (6) ◽  
pp. 1033-1041 ◽  
Author(s):  
M. Tanaka ◽  
B. Jouffrey
Keyword(s):  
Lattice Images ◽  
Beam Lattice

scholarly journals On Understanding the Administrative Law Subject

2020 ◽  
Vol 12 ◽  
pp. 18-20
Author(s):  
Olga N. Ordina ◽  
Keyword(s):  
Public Administration ◽  
Legal Theory ◽  
Administrative Law ◽  
Executive Power ◽  
Legal Science ◽  
Different Types ◽  
Common Concept ◽  
The Subject ◽  
Points Of View ◽  
Definition Of

In the administrative and legal science there is a refinement, change and expansion of the subject of the dynamic branch of administrative law, aimed at eliminating the resulting lag of legal theory from the legal reality. In our view, of the three basic categories that characterize the subject of administrative law, “public administration”, “executive power” and “administrativepublic activity”, the main generalization category is the category “administrative and public activities”. The phenomenon of the subject of administrative law refracts the problems and discussions inherent in the industry as a whole. In view of the existence of different points of view on the subject of administrative law, the legal science has not yet formulated a single definition of it. There is a tendency to overcome the conflict between different types of understanding, to bring together the positions of different concepts of understanding of administrative law in order to form a “universal” concept of it, to develop its common concept.

scholarly journals Characteristics of heat ceramics of Mordovian territory: on the example of the collection of Mordovian republican S. D. Erzia Fine Art Museum

2019 ◽  
Vol 11 (2) ◽  
pp. 222-231
Author(s):  
Andrey S. Barmenkov
Keyword(s):  
Comparative Analysis ◽  
Morphological Analysis ◽  
Fine Art ◽  
Art Museum ◽  
Maximum Extension ◽  
Different Types ◽  
The Subject ◽  
Functional Purpose

Introduction. The article is devoted to the description of pottery ceramics on Mordovian territory. The purpose of the article is to analyze the development of ceramics in Mordovian region. The object of the article is a collection of ceramics of Mordovian republican S.D. Erzia Fine Art Museum, the subject – the main features of the ceramics based on the morphological analysis of its exhibits. Materials and Methods. The material of the study was the results of the research of Russian scholars on ceramics of antiquity and modernity, as well as empirical materials presented by the ceramics funds of Mordovian republican S.D. Erzia Fine Art Museum. One of the main approaches implemented in the article is a comparative analysis of the exhibits based on the color of the shard. It allows the author to systematize utensils according to their functional purpose, and also to make an assumption about the various historical stages of the emergence of different types. Results and Discussion. The article systematizes the variety of forms of ceramics, reveals their quantitative relationships, the prevailing forms, and gives the comparative analysis of the existing forms. The classification of vessels was carried out in accordance with a number of criteria: the height and thickness of the neck, the design of the corolla cut, the diameter of the mouth and the maximum extension of the trunk, which allows one to draw conclusions about the similarity of the collection’s exhibits with other Mordоvian artefacts. Conclusion. It concludes about the existence of a certain standard in the production of ceramic dishes, and on the similarity of the studied ceramics and the collections of Russian monuments. Therefore, it states the preservation of local Mordovian pottery traditions in the course of wide interactions with Russian pottery ceramics.

scholarly journals The Utilization of Mobile Money Services in Small Scale Enterprises:A Case Study

2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Suryakanthi Tangirala ◽  
Samuel Nlondiwa
Keyword(s):  
Mobile Phone ◽  
Service Providers ◽  
Small Scale ◽  
Small Enterprises ◽  
Mobile Money ◽  
Different Types ◽  
The Subject ◽  
Transactional Costs

Mobile money is an electronic wallet service that allows users to store, send and receive money using their mobile phone. This research is an effort to find out the adoption and utilization of mobile money services in small sized enterprises located in Gaborone, Botswana. Inevitably, other aspects such as different types of transactions carried out using mobile money services in small business, customer’s perception on quality of mobile money service providers, impeding factors of mobile money adoption are also studied for wider understanding of the subject. The findings of the study show that small enterprises use mobile money services to carryout transactions but the level of adoption is not significant. The study revealed that transactional costs and connectivity issues are major barriers of adoption of mobile money services. In conclusion the study recommended that the service providers must improve the connectivity issues and reduce transaction charges in order to increase the utilization of mobile money services

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