scholarly journals Charge of clustered microparticles measured in spatial plasma afterglows follows the smallest enclosing sphere model

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. van Minderhout ◽  
J. C. A. van Huijstee ◽  
R. M. H. Rompelberg ◽  
A. Post ◽  
A. T. A. Peijnenburg ◽  
...  
Keyword(s):  
Single Particles ◽  
Particle Cluster ◽  
Perfect Agreement ◽  
Experimental Proof ◽  
Complex Plasma ◽  
Competing Models ◽  
Measured Ratio ◽  
Plasma Afterglow ◽  
Crucial Parameter ◽  
Spherical Microparticles

AbstractThe plasma-induced charge of non-spherical microparticles is a crucial parameter in complex plasma physics, aerosol science and astrophysics. Yet, the literature describes this charge by two competing models, neither of which has been experimentally verified or refuted. Here we offer experimental proof that the charge on a two-particle cluster (doublet) in the spatial afterglow of a low-pressure plasma equals the charge that would be obtained by the smallest enclosing sphere and that it should therefore not be based on its geometrical capacitance but rather on the capacitance of its smallest enclosing sphere. To support this conclusion, the size, mass and charge of single particles (singlets) and doublets are measured with high precision. The measured ratio between the plasma-afterglow-induced charges on doublets and singlets is compared to both models and shows perfect agreement with the predicted ratio using the capacitance of the smallest enclosing sphere, while being significantly dissimilar to the predicted ratio based on the particle’s geometrical capacitance.

scholarly journals Dust-Cloud Dynamics in a Complex Plasma Afterglow

2008 ◽  
Vol 36 (4) ◽  
pp. 1014-1015 ◽  
Author(s):  
L. Couedel ◽  
A.A. Samarian ◽  
M. Mikikian ◽  
L. Boufendi
Keyword(s):  
Dust Cloud ◽  
Complex Plasma ◽  
Cloud Dynamics ◽  
Plasma Afterglow

scholarly journals Dust charge distribution in complex plasma afterglow

2008 ◽  
Vol 84 (3) ◽  
pp. 35002 ◽  
Author(s):  
L. Couëdel ◽  
A. A. Samarian ◽  
M. Mikikian ◽  
L. Boufendi
Keyword(s):  
Charge Distribution ◽  
Complex Plasma ◽  
Dust Charge ◽  
Plasma Afterglow

scholarly journals Influence of the ambipolar-to-free diffusion transition on dust particle charge in a complex plasma afterglow

2008 ◽  
Vol 15 (6) ◽  
pp. 063705 ◽  
Author(s):  
L. Couëdel ◽  
A. A. Samarian ◽  
M. Mikikian ◽  
L. Boufendi
Keyword(s):  
Dust Particle ◽  
Particle Charge ◽  
Free Diffusion ◽  
Complex Plasma ◽  
Plasma Afterglow ◽  
Dust Particle Charge

Dust Cloud Dynamics in Complex Plasma Afterglow

2008 ◽  
Author(s):  
B. Layden ◽  
L. Couëdel ◽  
A. A. Samarian ◽  
M. Mikikian ◽  
S. V. Vladimirov ◽  
...  
Keyword(s):  
Dust Cloud ◽  
Complex Plasma ◽  
Cloud Dynamics ◽  
Plasma Afterglow

Residual Dust Charges in a Complex Plasma Afterglow

2011 ◽  
Vol 39 (11) ◽  
pp. 2764-2765 ◽  
Author(s):  
Brett Layden ◽  
Lénaïc Couedel ◽  
Alexander A. Samarian ◽  
Laïfa Boufendi
Keyword(s):  
Complex Plasma ◽  
Plasma Afterglow

scholarly journals Complex Plasma Afterglow

2009 ◽  
Vol 49 (4-5) ◽  
pp. 235-259 ◽  
Author(s):  
L. Couëdel ◽  
A. Mezeghrane ◽  
A.A. Samarian ◽  
M. Mikikian ◽  
Y. Tessier ◽  
...  
Keyword(s):  
Complex Plasma ◽  
Plasma Afterglow

3-D reconstruction of molecular shape from microcrystal thin sections

1983 ◽  
Vol 41 ◽  
pp. 748-749
Author(s):  
S. Cusack ◽  
J.-C. Jésior
Keyword(s):  
Three Dimensional ◽  
Molecular Shape ◽  
Biological Molecules ◽  
Fourier Space ◽  
Single Particles ◽  
Thin Sections ◽  
Standard Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dimensional Reconstruction

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).

Computer Assisted Image Reconstruction of Oligomer Structure

1976 ◽  
Vol 34 ◽  
pp. 472-473
Author(s):  
A.M. Jones ◽  
A. Max Fiskin
Keyword(s):  
Three Dimensional ◽  
Depth Of Field ◽  
Computer Assisted ◽  
Projection Data ◽  
Two Dimensional ◽  
Single Particles ◽  
Dimensional Reconstruction ◽  
Computer Assisted Image ◽  
The Fourier Transform ◽  
Space Approach

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.

New challenges to image processing posed by cryo-Electron microscopy of single particles

1991 ◽  
Vol 49 ◽  
pp. 422-423
Author(s):  
Joachim Frank
Keyword(s):  
Electron Microscopy ◽  
Phase Contrast ◽  
Particle Orientation ◽  
Single Particles ◽  
Contrast Transfer Function ◽  
Virtual Absence ◽  
Cryo Electron Microscopy ◽  
Spatial Frequencies ◽  
New Challenges ◽  
Particle Images

Compared with images of negatively stained single particle specimens, those obtained by cryo-electron microscopy have the following new features: (a) higher “signal” variability due to a higher variability of particle orientation; (b) reduced signal/noise ratio (S/N); (c) virtual absence of low-spatial-frequency information related to elastic scattering, due to the properties of the phase contrast transfer function (PCTF); and (d) reduced resolution due to the efforts of the microscopist to boost the PCTF at low spatial frequencies, in his attempt to obtain recognizable particle images.

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

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