scholarly journals The technology of steady electron irradiation of large size industrial products

2016 ◽  
Vol 17 (2) ◽  
pp. 199-203 ◽  
Author(s):  
T.V. Kovalinska ◽  
◽  
I.A. Ostapenko ◽  
V.I. Sakhno
Keyword(s):  
Electron Irradiation ◽  
Industrial Products ◽  
Large Size ◽  
Steady Electron

Borates as Agents for Negative Staining

1975 ◽  
Vol 33 ◽  
pp. 630-631
Author(s):  
William H. Massover
Keyword(s):  
Heavy Metal ◽  
Electron Irradiation ◽  
Heavy Atom ◽  
Amorphous State ◽  
Sodium Tetraborate ◽  
Potassium Sulfate ◽  
Large Size ◽  
Information Agents ◽  
Preliminary Study ◽  
Physical And Chemical

Negatively stained biological specimens generally can reveal information only to the quaternary level of macromolecular ultrastructure. In addition to the damaging influences of electron irradiation (e.g., 1), this limitation is due to such factors as the relatively large size of the staining agents being used, the physical and chemical interactions of the stain with the wet specimens, and the lack of a stable amorphous state in the dried stain. All heavy metal negative stains give much more contrast than is actually needed to reveal and record information; agents containing lighter atoms might provide improved qualities in some of the non-optical aspects while still giving adequate contrast. A preliminary study has shown that aluminum potassium sulfate and sodium tetraborate can function successfully as negative stains despite their lack of any heavy atom content. The tetraborate stain has provided information about ferritin and apoferritin that was not revealed with the usual stains.

Evaluation of single-electron movies of glutamine synthetase molecules

1983 ◽  
Vol 41 ◽  
pp. 280-281
Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel
Keyword(s):  
Electron Microscope ◽  
Glutamine Synthetase ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Structural Changes ◽  
Single Electron ◽  
Continuous Series ◽  
Digital Recording ◽  
Recording Device ◽  
Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

Radiation-Induced Precipitation at Thin Foil Surfaces in Ni-Be Alloys

1982 ◽  
Vol 40 ◽  
pp. 598-599
Author(s):  
T. Mukai ◽  
T. E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Electron Irradiation ◽  
High Vacuum ◽  
Thin Foil ◽  
Homogeneous Precipitation ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Radiation Induced

Radiation-induced homogeneous precipitation in Ni-Be alloys was recently observed by high voltage electron microscopy. A coupling of interstitial flux with solute Be atoms is responsible for the precipitation. The present investigation further shows that precipitation is also induced at thin foil surfaces by electron irradiation under a high vacuum.

Void-Lattice Formation in Natural Fluorite by Electron Irradiation

1976 ◽  
Vol 34 ◽  
pp. 614-615 ◽  
Author(s):  
L.E. Murr
Keyword(s):  
Electron Microscope ◽  
Electron Irradiation ◽  
Heavy Ion ◽  
High Energy ◽  
Stoichiometric Ratio ◽  
Direct Observations ◽  
Transmission Electron ◽  
Anion Vacancies ◽  
Cation And Anion Vacancies ◽  
Lattice Formation

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

Ordering in Ni4Mo by TEM and APFIM

1987 ◽  
Vol 45 ◽  
pp. 214-215
Author(s):  
E.A. Kenik ◽  
T.A. Zagula ◽  
M.K. Miller ◽  
J. Bentley
Keyword(s):  
Electron Irradiation ◽  
Low Temperatures ◽  
Short Range ◽  
Atom Probe ◽  
Range Order ◽  
Considerable Time ◽  
Probe Field ◽  
Disordered Phase ◽  
Transmission Electron ◽  
Diffraction Patterns

The state of long-range order (LRO) and short-range order (SRO) in Ni4Mo has been a topic of interest for a considerable time (see Brooks et al.). The SRO is often referred to as 1½0 order from the apparent position of the diffuse maxima in diffraction patterns, which differs from the positions of the LRO (D1a) structure. Various studies have shown that a fully disordered state cannot be retained by quenching, as the atomic arrangements responsible for the 1½0 maxima are present at temperatures above the critical ordering temperature for LRO. Over 20 studies have attempted to identify the atomic arrangements associated with this state of order. A variety of models have been proposed, but no consensus has been reached. It has also been shown that 1 MeV electron irradiation at low temperatures (∼100 K) can produce the disordered phase in Ni4Mo. Transmission electron microscopy (TEM), atom probe field ion microscopy (APFIM), and electron irradiation disordering have been applied in the current study to further the understanding of the ordering processes in Ni4Mo.

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

Immunoprobe localization in mammalian embryos

1990 ◽  
Vol 48 (3) ◽  
pp. 32-33
Author(s):  
Patricia G. Calarco ◽  
Margaret C. Siebert
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Thin Sections ◽  
Relative Lack ◽  
Large Size ◽  
Mammalian Embryos ◽  
Antigen Localization ◽  
Difficult Challenge ◽  
Lowicryl K4m ◽  
Fertilized Egg

Visualization of preimplantation mammalian embryos by electron microscopy is difficult due to the large size of the ircells, their relative lack of internal structure, and their highly hydrated cytoplasm. For example, the fertilized egg of the mouse is a single cell of approximately 75μ in diameter with little organized cytoskelet on and apaucity ofor ganelles such as endoplasmic reticulum (ER) and Golgi material. Thus, techniques that work well on tissues or cell lines are often not adaptable to embryos at either the LM or EM level.Over several years we have perfected techniques for visualization of mammalian embryos by LM and TEM, SEM and for the pre-embedding localization of antigens. Post-embedding antigenlocalization in thin sections of mouse oocytes and embryos has presented a more difficult challenge and has been explored in LR White, LR Gold, soft EPON (after etching of sections), and Lowicryl K4M. To date, antigen localization has only been achieved in Lowicryl-embedded material, although even with polymerization at-40°C, the small ER vesicles characteristic of embryos are unrecognizable.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

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