Simultaneous use of polarization microscopy and dark field techniques in the study of microorganisms

2021 ◽  
Author(s):  
Zdeněk Žižka
Keyword(s):  
Dark Field ◽  
Polarization Microscopy ◽  
Field Techniques ◽  
Simultaneous Use

On Distinguishing between Small Vacancy and Interstitial Dislocation Loops Using a Non-Conventional Weak Beam Dark Field Technique

1975 ◽  
Vol 33 ◽  
pp. 166-167
Author(s):  
Wei-Kuo Wu
Keyword(s):  
Habit Plane ◽  
Dark Field ◽  
Dislocation Loops ◽  
Bright Field ◽  
Burgers Vector ◽  
Field Techniques ◽  
Field Technique ◽  
The Core ◽  
Weak Beam ◽  
Image Width

It is well known that both the burgers vector and the habit plane of dislocation loops are needed in order to determine their type, e.g. vacancy or interstitial. The conventional bright field and dark field techniques give a dislocation image width ⋍300Å or an image shift from the core position even larger than the true size of a small dislocation loop. This makes loop type determination very difficult.In this paper, the newly developed weak beam dark field technique, which decreases the effective extinction distance, ξg, has been used to reduce the dislocation image width (∽1/3 ξg), so that the shape (habit plane) and loop types of small dislocation loops (<500Å) can be determined unambiguously.

Tetragonal precipitation in the system Y2O3-ZrO2

1983 ◽  
Vol 41 ◽  
pp. 58-59
Author(s):  
V. Lanteri ◽  
A. H. Heuer ◽  
T. E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Tetragonal Phase ◽  
Dark Field ◽  
Stabilized Zirconia ◽  
Two Phase ◽  
Field Techniques ◽  
Transmission Electron ◽  
Habit Planes

The major applications of partially stabilized zirconia (PSZ) concern materials in which the microstructures are in the two phase regions (cubic-tetragonal or cubic-monoclinic). The aim of this paper is to discuss the occurrence of tetragonal precipitation in yttria-PSZ. Despite the similarity with other doped zirconia alloys (Mg-PSZ, Ca-PSZ), the shape, the habit planes and mechanisms of precipitation are found to be different for Y-PSZ. Single crystals, obtained from skull melting, with composition 8w%-Y2O3 were examined by transmission electron microscopy (TEM) and the tetragonal phase was imaged using standard dark field techniques.

On dark field techniques in transmission electron microscopy

1975 ◽  
Vol 1 (1) ◽  
pp. 67-78 ◽  
Author(s):  
K. Shirota ◽  
T. Yamamoto ◽  
T. Yanaka ◽  
O. Vingsbo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dark Field ◽  
Field Techniques ◽  
Transmission Electron

Hrem Structural Studies of TbFeCo Thin Films

1989 ◽  
Vol 151 ◽  
Author(s):  
Z. G. Li ◽  
David J. Smith ◽  
K. Sickafus
Keyword(s):  
Thin Films ◽  
High Resolution Electron Microscopy ◽  
Dark Field ◽  
Structural Studies ◽  
Bright Field ◽  
Experimental Conditions ◽  
Field Techniques ◽  
Resolution Electron ◽  
Top View ◽  
Deposition Conditions

ABSTRACTThe microstructure of TbFeCo thin films prepared under different deposition conditions has been observed in crosssection and top-view using high-resolution electron microscopy, as well as conventional bright-field and dark-field techniques. A comparison has been made with FeCo thin films prepared under identical experimental conditions. Very fine microcrystals (sizes 2–5nm) were observed in the basically amorphous TbFeCo thin films whereas much larger crystals (sizes 20–50nm) were visible in the primarily crystalline FeCo thin films. It was also found that the size of the nanocrystals in the TbFeCo films depended upon the argon partial pressure during deposition.

Confocal scanning dark-field polarization microscopy

1994 ◽  
Vol 33 (7) ◽  
pp. 1274 ◽  
Author(s):  
S. Kimura ◽  
T. Wilson
Keyword(s):  
Dark Field ◽  
Polarization Microscopy ◽  
Field Polarization ◽  
Confocal Scanning

scholarly journals Analysis of the Nanoparticle Dispersion and Its Effect on the Crystalline Microstructure in Carbon-Additivated PA12 Feedstock Material for Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3312
Author(s):  
Tim Hupfeld ◽  
Alexander Sommereyns ◽  
Farbod Riahi ◽  
Carlos Doñate-Buendía ◽  
Stan Gann ◽  
...  
Keyword(s):  
Rapid Development ◽  
Dark Field ◽  
Polarization Microscopy ◽  
Powder Bed Fusion ◽  
Nanoparticle Dispersion ◽  
Laser Powder Bed Fusion ◽  
Scanning Calorimetry ◽  
Powder Bed ◽  
Manufacturing Technologies ◽  
Feedstock Material

Driven by the rapid development of additive manufacturing technologies and the trend towards mass customization, the development of new feedstock materials has become a key aspect. Additivation of the feedstock with nanoparticles is a possible route for tailoring the feedstock material to the printing process and to modify the properties of the printed parts. This study demonstrates the colloidal additivation of PA12 powder with laser-synthesized carbon nanoparticles at >95% yield, focusing on the dispersion of the nanoparticles on the polymer microparticle surface at nanoparticle loadings below 0.05 vol%. In addition to the descriptors “wt%” and “vol%”, the descriptor “surf%” is discussed for characterizing the quantity and quality of nanoparticle loading based on scanning electron microscopy. The functionalized powders are further characterized by confocal dark field scattering, differential scanning calorimetry, powder rheology measurements (avalanche angle and Hausner ratio), and regarding their processability in laser powder bed fusion (PBF-LB). We find that heterogeneous nucleation is induced even at a nanoparticle loading of just 0.005 vol%. Finally, analysis of the effect of low nanoparticle loadings on the final parts’ microstructure by polarization microscopy shows a nanoparticle loading-dependent change of the dimensions of the lamellar microstructures within the printed part.

Utilizing Dark Field Electron Microscopy to Produce Lantern Slides

1974 ◽  
Vol 32 ◽  
pp. 116-117
Author(s):  
J. N. Meador ◽  
C. N. Sun ◽  
H. J. White
Keyword(s):  
Electron Microscope ◽  
Electron Micrographs ◽  
Dark Field ◽  
Limiting Factor ◽  
Clinical Laboratories ◽  
Field Electron ◽  
Time Element ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dark Field Micrographs

The electron microscope is being utilized more and more in clinical laboratories for pathologic diagnosis. One of the major problems in the utilization of the electron microscope for diagnostic purposes is the time element involved. Recent experimentation with rapid embedding has shown that this long phase of the process can be greatly shortened. In rush cases the making of projection slides can be eliminated by taking dark field electron micrographs which show up as a positive ready for use. The major limiting factor for use of dark field micrographs is resolution. However, for conference purposes electron micrographs are usually taken at 2.500X to 8.000X. At these low magnifications the resolution obtained is quite acceptable.

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

Evaluation of the dark field method for large association of spread DNA

1978 ◽  
Vol 36 (2) ◽  
pp. 190-191
Author(s):  
Douglas C. Barker
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Mitochondrial Dna ◽  
Extraction Method ◽  
Field Method ◽  
Dark Field ◽  
Kinetoplast Dna ◽  
Field Electron ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A number of satisfactory methods are available for the electron microscopy of nicleic acids. These methods concentrated on fragments of nuclear, viral and mitochondrial DNA less than 50 megadaltons, on denaturation and heteroduplex mapping (Davies et al 1971) or on the interaction between proteins and DNA (Brack and Delain 1975). Less attention has been paid to the experimental criteria necessary for spreading and visualisation by dark field electron microscopy of large intact issociations of DNA. This communication will report on those criteria in relation to the ultrastructure of the (approx. 1 x 10-14g) DNA component of the kinetoplast from Trypanosomes. An extraction method has been developed to eliminate native endonucleases and nuclear contamination and to isolate the kinetoplast DNA (KDNA) as a compact network of high molecular weight. In collaboration with Dr. Ch. Brack (Basel [nstitute of Immunology), we studied the conditions necessary to prepare this KDNA Tor dark field electron microscopy using the microdrop spreading technique.

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