Determination of the Mean Size of Disordered Regions Induced in Germanium by Fast‐Neutron Bombardment at Low Temperature

1965 ◽  
Vol 36 (11) ◽  
pp. 3450-3452 ◽  
Author(s):  
Nguyen Van Dong
Keyword(s):  
Low Temperature ◽  
Fast Neutron ◽  
Neutron Bombardment ◽  
Mean Size ◽  
The Mean ◽  
Disordered Regions

Determination of the mean size of submicron particles by electron probe microanalysis

1995 ◽  
Vol 24 (1) ◽  
pp. 13-18 ◽  
Author(s):  
A. Berner ◽  
I. Levin ◽  
L. Klinger ◽  
D. G. Brandon
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Submicron Particles ◽  
Mean Size ◽  
The Mean

The Determination of Crystallite Size and Size Distribution from Broadened X-Ray Diffraction Lines

1961 ◽  
Vol 5 ◽  
pp. 94-103 ◽  
Author(s):  
H. F. Quinn ◽  
P. Cherin
Keyword(s):  
Harmonic Analysis ◽  
Size Distribution ◽  
Fourier Coefficients ◽  
Distribution Functions ◽  
Composite Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mean Size ◽  
The Mean

AbstractMagnesium oxide crystallites having mean dimensions in the range of 25–1000 A can be prepared by controlled thermal decomposition of the carbonate.Following some earlier investigations of Birks and Friedman, we have determined the mean size and size distribution of several such MgO samples from the broadened X-ray diffraction lines which they exhibit. Contrary to the procedure of the above investigators, the harmonic analysis due to Stokes has been used to correct for instrumental broadening and values of mean-size and size-distribution functions obtained from the Fourier coefficients by the methods of Warren and Averbach.The results obtained are compared with average sizes and distributions obtained by direct examination of the samples in an electron microscope.A composite sample has been prepared by mixing known quantities of the sample previously studied. The distribution function obtained by harmonic analysis of one diffraction line of the composite sample is compared with the function calculated from the distributions of its components.Conclusions are drawn concerning the significance of the results obtained by the Warren technique: in particular, the average sizes obtained by this method are compared with those given by the approximate method used by Birks and Friedman.

scholarly journals Small iron meteoroids

2019 ◽  
Vol 625 ◽  
pp. A106 ◽  
Author(s):  
David Čapek ◽  
Pavel Koten ◽  
Jiří Borovička ◽  
Vlastimil Vojáček ◽  
Pavel Spurný ◽  
...  
Keyword(s):  
Initial Velocity ◽  
Luminous Efficiency ◽  
Light Curves ◽  
Zenith Distance ◽  
Video Observations ◽  
Wide Range ◽  
Mean Size ◽  
The Mean ◽  
Heliocentric Orbits

Context. A significant fraction of small meteors are produced by iron meteoroids. Their origin and the interaction with the atmosphere have not been well explained up to now. Aims. The goals of the study are to observe faint, slow, low altitude meteors, to identify candidates for iron meteoroids among them, to model their ablation and light curves, and to determine their properties. Methods. Double station video observations were used for the determination of atmospheric trajectories, heliocentric orbits, light curves, and spectra of meteors. Meteors with iron spectra or of suspected iron composition based on beginning heights and light curves were modeled. The immediate removal of liquid iron from the surface as a cloud of droplets with Nukiyama–Tanasawa size distribution and their subsequent vaporization was assumed as the main ablation process on the basis of our previous work. The numerical model has only five parameters: meteoroid initial velocity v∞, zenith distance z, initial mass m∞, mean drop size Ddr, and luminous efficiency τ. The theoretical light curves were compared with the observed ones. Results. The model is able to explain the majority of the selected light curves, and meteoroid parameters that are not directly observable – m∞, Ddr, and τ – are determined. Unlike in most meteor studies, the mass and luminous efficiency are determined independently. Luminous efficiency ranges from 0.08 to 5.8%; it weakly decreases with increasing initial meteoroid mass. No simple dependency on initial velocity was found. The mean size of iron drops depends on the meteoroid velocity. Slower meteoroids can produce drops with a wide range of mean sizes, whereas faster ones are better matched with larger drops with a smaller dispersion of sizes.

A Novel Tick Film Nanocrystalline Y2O3:Eu3+ Phosphor Synthesized by Post-Dispersion Treatment at Low Temperature

2003 ◽  
Vol 789 ◽  
Author(s):  
Sung-Jei Hong ◽  
Min-Gi Kwak ◽  
Dae-Gyu Moon ◽  
Won-Keun Kim ◽  
Jeong-In Han
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Thick Film ◽  
Yttrium Oxide ◽  
Photoluminescence Properties ◽  
Dispersing Agent ◽  
Heat Treated ◽  
Mean Size ◽  
The Mean ◽  
Cubic Structure

ABSTRACTIn this study, a novel thick film nanocrystalline phosphor is synthesized by using postdispersion treatment at low temperature. The post-dispersion treatment is to prevent the agglomeration between the precursors by mixing the organic dispersing agent with them before heat-treatment. The mean size of the particle heat-treated at 500°C is 4nm. Also, europium is uniformly distributed in the yttrium oxide with deviation below 0.5%. The nanocrystalline phosphor is principally composed of cubic structure having preferred orientation of <222>, <440>, and <400>. The photoluminescence properties of the nanocrystalline phosphor characterized with monochrometric systems reveals that the main PL peak is detected at 611 nm, and thick film nanocrystalline phosphor with 15wt% europium exhibits better properties.

Self-Propagating Combustion Synthesis and Characterization of ODS Fe-Base Superalloy Powders

2013 ◽  
Vol 747-748 ◽  
pp. 641-646
Author(s):  
Cun Guang Chen ◽  
Zhi Meng Guo ◽  
Ji Luo ◽  
Wei Wei Yang ◽  
Jun Jie Hao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Combustion Synthesis ◽  
Malic Acid ◽  
Selective Reduction ◽  
Synthesis And Characterization ◽  
Mean Size ◽  
The Mean ◽  
Concentrated Solution ◽  
Base Superalloy

A new method was employed to synthesize nanosized Y2O3 dispersion strengthened Fe-base superalloy powders using self-propagating combustion. A concentrated solution of nitrates of iron and yttrium was used as oxidizer, malic acid as fuel to fabricate Fe2O3/Y2O3 powders at low temperature. Afterwards, uniform and fine Fe/2wt.%Y2O3 powders were obtained by selective reduction with hydrogen, on the surface of which dispersive Y2O3 particles of the mean size of 30 - 50 nm were observed.

Weak Beam Imaging and Diffraction Studies of Stacking Faults in Silicon

1976 ◽  
Vol 34 ◽  
pp. 590-591
Author(s):  
T. Y. Tan ◽  
W. K. Tice
Keyword(s):  
Fast Neutron ◽  
Rapid Determination ◽  
Stacking Faults ◽  
Imaging Method ◽  
Large Reduction ◽  
Dislocation Loops ◽  
Fringe Spacing ◽  
Weak Beam ◽  
Kinematical Theory

In studying ion implanted semiconductors and fast neutron irradiated metals, the need for characterizing small dislocation loops having diameters of a few hundred angstrom units usually arises. The weak beam imaging method is a powerful technique for analyzing these loops. Because of the large reduction in stacking fault (SF) fringe spacing at large sg, this method allows for a rapid determination of whether the loop is faulted, and, hence, whether it is a perfect or a Frank partial loop. This method was first used by Bicknell to image small faulted loops in boron implanted silicon. He explained the fringe spacing by kinematical theory, i.e., ≃l/(Sg) in the fault fringe in depth oscillation. The fault image contrast formation mechanism is, however, really more complicated.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Determination of Plasminogen in Clots and Thrombi

1966 ◽  
Vol 16 (01/02) ◽  
pp. 038-050 ◽  
Author(s):  
Ulla Hedner ◽  
Inga Marie Nilsson ◽  
B Robertson
Keyword(s):  
Mean Value ◽  
Main Mechanism ◽  
Clot Lysis ◽  
Post Mortem ◽  
Digestion Time ◽  
Normal Volunteers ◽  
Casein Solution ◽  
The Mean

SummaryThe plasminogen content was determined by a casein method in plasma and serum from 20 normal volunteers. The mean plasminogen content was found to be 10.1 ACU (the arbitrary caseinolytic unit defined in such a way that using a 3% casein solution and a digestion time of 20 min. at 37°C, 10 ACU gave an extinction of 0.300). No difference between serum and plasma regarding the plasminogen content was found.Plasminogen was determined in drained and drained plus washed clots prepared from 2 ml plasma. The highest values found in the drained clots were 0.9 ACU/clot and 0.2 ACU/clot in the drained plus washed clots.Plasminogen was also determined in drained and drained plus washed clots prepared from plasma with added purified plasminogen. The plasminogen was recovered in the washing fluid. According to these tests, then, purified added plasminogen is washed out of the clots.The plasminogen content of 20 thrombi obtained post mortem was also determined. The mean value was found to be 0.7 ACU/cm thrombus. Judging from our results, the “intrinsic clot lysis theory” is not the main mechanism of clot dissolution.

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