An assessment of high voltage electron microscopy (HVEM). An invited review
TL;DR: High voltage electron microscopy (HVEM) has been extensively applied in the field of materials science as discussed by the authors, covering the study of heavy metals, ceramics and minerals, large-scale structures, dynamic processes and radiation damage.
About: This article is published in Materials Science and Engineering.The article was published on 1977-04-01. It has received 1700 citations till now. The article focuses on the topics: High voltage electron microscopy & Scanning transmission electron microscopy.
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TL;DR: The most promising nanoscale fillers are layered silicate nanoclays such as montmorillonite and kaolinite as mentioned in this paper, which can provide active and/or smart properties to food packaging systems.
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Abstract: Nanocomposites, a high performance material exhibit unusual property combinations and unique design possibilities. With an estimated annual growth rate of about 25% and fastest demand to be in engineering plastics and elastomers, their potential is so striking that they are useful in several areas ranging from packaging to biomedical applications. In this unified overview the three types of matrix nanocomposites are presented underlining the need for these materials, their processing methods and some recent results on structure, properties and potential applications, perspectives including need for such materials in future space mission and other interesting applications together with market and safety aspects. Possible uses of natural materials such as clay based minerals, chrysotile and lignocellulosic fibers are highlighted. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors of the aerospace, automotive, electronics and biotechnology industries.
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TL;DR: In this article, rate theory equations for the spatially averaged interstitial and vacancy concentrations in irradiated materials containing sessile dislocation loops, deformation dislocations, voids and coherent or incoherent precipitates are derived.
592 citations
TL;DR: In this paper, the velocities of unpinned edge dislocations in 3¼% silicon-iron have been measured as a function of stress over a range of five orders of magnitude in velocity from 10−7 cm/sec to 10−2 cm /sec.
Abstract: A method has been developed whereby the velocity of motion of fresh dislocations introduced into a crystal by scratching the surface may be measured as a function of stress. The velocities of unpinned edge dislocations in 3¼% silicon‐iron have been measured as a function of stress over a range of five orders of magnitude in velocity from 10−7 cm/sec to 10−2 cm/sec. The velocity has been found to be very sensitive to the applied stress in this velocity range. Measurements of velocity as a function of stress have been made for four temperatures in the range 78°K to 373°K. It has been found that over this range of temperature the yield stress changes with temperature in the same way as the stress to produce a constant velocity of dislocation motion. From the result it is concluded that the rise in yield stress at low temperatures exhibited by this silicon iron is due primarily to an increase in the lattice resistance to dislocation motion and not to an increase in the Cottrell locking force. Preliminary expe...
383 citations
238 citations
TL;DR: In this article, the authors analyzed the origin and growth mechanism of the dislocation network in Ga1−xAlxAs-GaAs-DH lasers and found that the growth process is characterized by successive climb of a dislocation crossing the n−Ga1−alxAs, p−GaAs, and p•GaAs layers in the stripe area, leading to the formation of a three-dimensional dislocation dipole network.
Abstract: The rapid degradation phenomenon in Ga1−xAlxAs–GaAs DH lasers has been associated with the growth of a dislocation network during the device operation. The nature of these defects has been analyzed by transmission electron microscopy in an effort to understand their origin and growth mechanism. The propagation of the dislocation network is found to take place by successive climb of a dislocation crossing the n‐Ga1−xAlxAs, p‐GaAs, and p‐Ga1−xAlxAs layers in the stripe area. The climb process leads to the formation of a three‐dimensional dislocation dipole network which extends through the three epitaxial layers and remains confined to the stripe area. A tentative model which discusses the network growth process is presented. The source of the very large vacancy concentration involved in the climb process has been attributed to the interfaces between the binary and ternary layers. The fast climb rate has been related to large drift forces acting on the vacancies during the device operation. The dominant drift forces are thought to be electrical and elastic in nature.
160 citations
TL;DR: In this paper, the relationship between the particle size and the size of the cavity nucleated at the particle is discussed as is the frequency of cavities as a function of particle dimensions and interparticle spacing.
133 citations