Abstract Electron optical experiments on Al foils have revealed individual dislocations in the interior of metal. The arrangement and movement been observed. Most occur boundaries a substructure, diameter subrains being order 1 μ, or more. Tilt-boundaries, networks dislocation nodes resolved. results apply to aluminium recovered at 350°c after heavy deformation by beating; density is 1010/cm2. can be seen move along traces (111) slip planes; motion either rapid slow jerky. Cross-slip screw...

This paper describes a kinematical theory of electron microscope images dislocations observed by transmission in thin crystalline foils. The contrast is essentially phase the Bragg diffracted beams, differences being due to displacements atoms from their positions ideally perfect crystal. explains many characteristic features images, such as dependence on orientation, reversal bright and dark field fact that are generally position width general nature profile, occurrence dotted dislocations,...

The dynamical theory of electron diffraction is developed in a form suitable for the computation images crystal lattice defects such as dislocations observed by transmission microscopy. As shown previous kinematical theory, contrast arises because waves diffracted atoms near defect are changed phase result displacements these from perfect positions. two-beam symmetrical Laue case derived simple principles methods similar to those used Darwin Bragg case. Simultaneous differential equations...

Numerical solutions for the transmitted and diffracted wave intensities when electrons pass through a thin foil containing dislocation, are obtained by use of previously derived formulation dynamical diffraction theory which takes account anomalous absorption effects. The results variety cases physical interest compared with transmission electron micrographs appears capable explaining most observed also confirms many predictions an earlier kinematical about visibility width dislocation...

The two-beam dynamical theory of electron diffraction in absorbing crystals has been applied to explain features bend and thickness extinction contours images stacking faults observed on transmission micrographs metal foils. Inelastic scattering processes affect the intensities elastically scattered waves give rise 4 anomalous ’ (Borrmann) effects. formal takes account these effects phenomenologically by use a complex lattice potential but ignores contribution inelastically electrons image....

Abstract The dynamical theory of electron diffraction is applied to the case a plate-like crystal containing stacking fault. effect fault produce phase difference in waves diffracted by two parts faulted crystal. Expressions for wave functions and corresponding intensities, predicting interference fringes region overlap are derived. It shown that problem one three coherent waves, contrast wedge where only involved. At Bragg reflecting position spacing half extinction distance large...

Abstract A high temperature stage fitted to a Siemens Elmiskop 1 electron microscope has been used study directly the annealing of prismatic dislocation loops in thin foils prepared from quenched and aged bulk specimens aluminium. In range 170-200°c are observed shrink eventually disappear. Observations on dislocations other than also present show that they become smoother while disappearing. The results interpreted terras climb by vacancy emission, case foils, where supersaturation effects...

Further experiments by transmission electron microscopy on thin sections of stainless steel deformed small amounts have enabled extended dislocations to be observed directly. The arrangement and motion whole partial been followed in detail. Many the are found piled up against grain boundaries. Other observations include formation wide stacking faults, interaction with twin boundaries, at edges foils. An estimate is made stacking-fault energy from a consideration stresses present, properties...

Bare soil (BS) identification through satellite remote sensing can potentially play a critical role in understanding and managing properties essential for climate regulation ecosystem services. From 191 papers, this review synthesises advancements BS detection methodologies, such as threshold masking classification algorithms, while highlighting persistent challenges spectral confusion inconsistent validation practices. The analysis reveals an increasing reliance on data applications digital...

Debye–Waller factors and absorptive scattering are given of 44 elemental crystals over the temperature range from 1 to 1000 K or melting temperature, whichever is smaller. The derived experimentally determined phonon density states accuracy these typically 2 3%. Necessary data have also been compiled for an additional 22 which characteristic Debye temperatures known. These can be used estimate factor at any using analytical expression states.

Abstract This paper presents the first international assessment of phosphorus concentrations in groundwater, using data from Republic Ireland, Northern Scotland, England and Wales. Phosphorus is considered to be main limiting nutrient most freshwater ecosystems. Controlling inputs thus key reducing eutrophication managing ecological quality. Very little attention has been paid evaluating transfers via groundwater due long‐held belief that adsorption metal complex formation retain majority...

A robust algorithm and computer program have been developed for the parameterization of elastic absorptive electron atomic scattering factors. The is based on a combined modified simulated-annealing least-squares method, works well fitting both factors with five Gaussians. As an application this program, parameterized all neutral atoms s up to 6 Å−1. Error analysis shows that present results are considerably more accurate than previous analytical fits in terms mean square value deviation...

Abstract Interesting observations of bands contrast on scanning electron micrographs bulk single-crystal specimens reported by Coates (1967) are interpreted in terms anomalous absorption effects similar to those discussed earlier for x-ray emission from thin foils Hirsch et at. (1962). It is shown that the may be considered as 'inverse' channeling patterns. Some possible consequences effect discussed.

Experiments by transmission electron microscopy on thin foils of stainless steel have enabled the interaction dislocations different slip systems to be observed in detail. Interactions are most frequently piled-up groups as a result attractions between and isolated other systems. The combination takes place over short lengths only, leading formation segments resultant dislocation networks. interactions first discussed theoretically terms undissociated then ribbon dislocations. Various...

Abstract The theory of the previous paper is applied to case stacking faults in close packed lattices. Electron optical experiments on thin foils stainless steel are described, results which good agreement with theory.

Abstract The dynamical theory of electron diffraction including a term to take account absorption has been applied explain some contrast anomalies observed at extinction contours and stacking faults on transmission micrographs metal foils. is present phenomenological because the detailed mechanism process not understood. This paper reports preliminary results compares them with observations.

Abstract A high temperature specimen stage has been used to study precipitation in thin foils of Al +4% Cu alloy directly the electron microscope. Precipitates a few hundred Angstroms size am observed form minutes at temperatures ∼250° 300°c. This initial identified by diffraction as θ′ phase, and is found occur e well-defined single orientation with respect matrix. The consistent one those formed bulk material. growth higher larger θ precipitates expense also studied. results show that Mars...

Triclosan (TCS) is a broad-spectrum antimicrobial used in consumer products including toothpaste and hand soap. After being used, TCS washed or rinsed off residuals that are not biodegraded otherwise removed during wastewater treatment can enter the aquatic environment effluents sludges. The environmental exposure toxicity of has been subject various scientific regulatory discussions recent years. There have number publications past 5 y reporting toxicity, fate transport, in-stream...

Widespread pollution of groundwater by nutrients due to 20th century agricultural intensification has been major concern in the developed world for several decades. This paper considers River Thames catchment (UK), where water‐quality monitoring at Hampton (just upstream London) produced continuous records nitrate last 140 years, longest record water chemistry anywhere world. For same period, data are available characterize changes both land use and management an annual scale. A modeling...