Preferred Orientation of Crystalline Particles within Tablets. I. Method for Measuring Crystalline Particle Orientation within Tablets

AbstractPreferred orientation of clay particles in various clay mounts was measured with an X-ray texture diffractometer. Pole distributions are approximately symmetrical about the normal to the sample. Particle orientation is characterized by standard deviations ranging from 7° for thin sedimented layers, to 20° and more for dry-pressed samples, the latter showing less dependence on particle size. The orientation of the reflecting particles may span a considerable angular range affecting the intensities of diffraction peaks observed on contemporary powder diffractometers, even those with moderate axial divergence. A theory based on the diffractometer geometry was developed to calculate the effect of particle orientation. Results are presented as modified Lorentz factors for orientations deduced from experimental observations. In qualitative X-ray diffractometry of clays, preference must be given to preparation techniques which ensure a high degree of preferred orientation and therefore strong enhancement of basal reflections. In quantitative X-ray diffractometry, the main factor is the reproducibility of particle orientation, and suction and dry pressing are promising methods of sample preparation.

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Review to Grigorii P. Kokhanenko et al. "Scanning Polarization Lidar LOSA-M3: Opportunity for Research of Crystalline Particle Orientation in the Clouds of Upper Layers"

10.5194/amt-2019-326-rc2 ◽

2019 ◽

Author(s):

Anonymous

Keyword(s):

Particle Orientation ◽

Crystalline Particle

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Aluminum Matrix Texture and Particle Characterization in Al-Al3Ti FGMs Produced by a Centrifugal Solid-Particle Method

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.105.415 ◽

2005 ◽

Vol 105 ◽

pp. 415-420 ◽

Cited By ~ 8

Author(s):

P.D. Sequeira ◽

Yoshimi Watanabe ◽

L.A. Rocha

Keyword(s):

Solid Particle ◽

Centrifugal Force ◽

Outer Surface ◽

Volume Fraction ◽

Intermetallic Particle ◽

Outer Region ◽

Aluminum Matrix ◽

Particle Method ◽

Preferred Orientation ◽

Particle Orientation

The centrifugal solid-particle method has proved to be effective in producing functionally graded materials (FGMs). In this study, Al-Al3Ti FGMs, were produced by this centrifugal method, from an Al-5 wt % Ti master alloy. Applied centrifugal forces were 30, 60 and 120G (units of gravity). Samples from the outer surface of each specimen were cut and aluminum matrix texture analyzed by Schulz reflection method. Analysis of the resulting pole figures indicates a preferred orientation along the (200) plane for the aluminum matrix crystals. Furthermore, increasing the applied centrifugal force enhances the orientation effect. Al3Ti platelet orientation and area fraction at the samples’ outer surface along three observation planes were also measured. The Al3Ti platelets in the outer region are orientated perpendicular to the centrifugal force direction along two of the observed planes, also an increase in centrifugal force leads to an increase in orientation in those two planes. The intermetallic particle volume fraction also increases with higher applied centrifugal force, although not significantly. A correlation appears to exist between particle orientation and the preferred orientation of the matrix.

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A novel cryo-electron microscopy support film based on 2D crystal of HFBI protein

10.1101/2021.11.09.467987 ◽

2021 ◽

Author(s):

Hongcheng Fan ◽

Bo Wang ◽

Yan Zhang ◽

Yun Zhu ◽

Bo Song ◽

...

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Electrostatic Interactions ◽

Preferred Orientation ◽

Particle Orientation ◽

Quality Data ◽

Water Interface ◽

Small Proteins ◽

Cryo Electron Microscopy ◽

Air Water Interface

Cryo-electron microscopy (cryo-EM) has become the most powerful tool to resolve the high-resolution structures of biomacromolecules in solution. However, the air-water interface induced preferred orientation, dissociation or denaturation of biomacromolecules during cryo-vitrification is still a major limitation factor for many specimens. To solve this bottleneck, we developed a new type of cryo-EM support film using the 2D crystal of hydrophobin I (HFBI) protein. The HFBI-film utilizes its hydrophilic side to adsorb protein particles via electrostatic interactions and keep air-water interface away, allowing thin-enough ice and high-quality data collection. The particle orientation distribution can be optimized by changing the buffer pH. We, for the first time, solved the cryo-EM structure of catalase (2.28 Å) that exhibited strong preferred orientation using conventional cryo-vitrification protocol. We further proved the HFBI-film is suitable to solve the high-resolution structures of small proteins including aldolase (150 kDa, 3.34 Å) and hemoglobin (64 kDa, 3.6 Å). Our work implied that the HFBI-film will have a wide application in the future to increase the successful rate and efficiency of cryo-EM.

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Scanning polarization lidar LOSA-M3: opportunity for research of crystalline particle orientation in the ice clouds

Atmospheric Measurement Techniques ◽

10.5194/amt-13-1113-2020 ◽

2020 ◽

Vol 13 (3) ◽

pp. 1113-1127

Author(s):

Grigorii P. Kokhanenko ◽

Yurii S. Balin ◽

Marina G. Klemasheva ◽

Sergei V. Nasonov ◽

Mikhail M. Novoselov ◽

...

Keyword(s):

Tilt Angle ◽

Measurement Errors ◽

Polarization State ◽

Angle Measurement ◽

Particle Orientation ◽

Exponential Dependence ◽

Crystalline Particle ◽

Ice Cloud ◽

Horizontal Orientation ◽

First Results

Abstract. The article describes a scanning polarization lidar, LOSA-M3, developed at the V. E. Zuev Institute of Atmospheric Optics, the Siberian Branch of the Russian Academy of Sciences (IAO SB RAS), as part of the common use center “Atmosphere”. The first results of studying the crystalline particle orientation by means of this lidar are presented herein. The main features of the LOSA-M3 lidar are the following: (1) an automatic scanning device, which allows changing the sensing direction in the upper hemisphere at the speed up to 1.5∘ s−1 with the accuracy of the angle measurement setting of at least 1 arcmin, (2) separation of the polarization components of the received radiation that is carried out directly behind the receiving telescope without installing the elements distorting polarization, such as dichroic mirrors and beam splitters, and (3) continuous alternation of the initial polarization state (linear–circular) from pulse to pulse that makes it possible to evaluate some elements of the scattering matrix. For testing lidar performance several series of measurements of the ice cloud structure in the zenith scan mode were carried out in Tomsk in April–June 2018. The results show that the degree of horizontal orientation of particles can vary significantly in different parts of the cloud. The dependence of signal intensity on the tilt angle reflects the distribution of particle deflection relative to the horizontal plane and is well described by the exponential dependence. The values of the cross-polarized component in most cases show a weak decline of intensity with the angle. However, these variations are smaller than the measurement errors. We can conclude that they are practically independent of the tilt angle. In most cases the scattering intensity at the wavelength of 532 nm has a wider distribution than at 1064 nm.

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The Microstructure of Shock-Synthesized Diamond

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006163x ◽

1967 ◽

Vol 25 ◽

pp. 324-325

Author(s):

Lucien F. Trueb

Keyword(s):

Single Crystals ◽

Preferred Orientation ◽

High Magnification ◽

Texture Pattern ◽

Shock Process ◽

New Type ◽

Diffraction Diagram

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.

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Characteristic Geometry and Diffraction Contrast of Dispersed ThO2 Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062750 ◽

1969 ◽

Vol 27 ◽

pp. 168-169

Author(s):

R. J. Horylev ◽

L. E. Murr

Keyword(s):

Dark Field ◽

Particle Orientation ◽

Contrast Effects ◽

Strain Fields ◽

Diffraction Contrast ◽

Dispersed Particles ◽

Field Electron Microscopy ◽

Dark Field Electron ◽

Particle Images ◽

Diffraction Effects

Smith has shown by dark-field electron microscopy of extracted ThO2 particles from TD-nickel (2% ThO2) that they possess single crystal characteristics. It is generally assumed that these particle dispersions are incoherent. However, some diffraction effects associated with the particle images appeared to be similar to coherency strain fields. The present work will demonstrate conclusively that ThO2 dispersed particles in TD-nickel (2% ThO2) and TD-NiCr (2% ThO2, 20% Cr, Ni) are single crystals. Moreover, the diffraction contrast effects are extinction fringes. That is, these effects arise because of the particle orientation with respect to the electron beam and the extinction conditions for various operating reflections The particles are in fact incoherent.

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Existence of Cubic ZrO2 at 300°C on Bulk Zirconium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062749 ◽

1969 ◽

Vol 27 ◽

pp. 166-167

Author(s):

R.A. Ploc

Keyword(s):

Metal Oxide ◽

Metal Substrate ◽

Preferred Orientation ◽

Monoclinic Zirconia ◽

Epitaxial Relationship

The manner in which ZrO2 forms on zirconium at 300°C in air has been discussed in the first reference. In short, monoclinic zirconia nucleates and grows with a preferred orientation relative to the metal substrate. The mode of growth is not well understood since an epitaxial relationship which gives minimum misfit between the zirconium ions in the metal/oxide combination is not realized. The reason may be associated with a thin cubic or tetragonal layer of ZrO2 between the inner oxygen saturated metal and the outer monoclinic zirconia.

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