Fine structure of the diffraction image of an edge dislocation in high-resolution section topography

Author(s):  
E. V. Suvorov ◽  
I. A. Smirnova
Author(s):  
K. Ogura ◽  
H. Nishioka ◽  
N. Ikeo ◽  
T. Kanazawa ◽  
J. Teshima

Structural appraisal of thin film magnetic media is very important because their magnetic characters such as magnetic hysteresis and recording behaviors are drastically altered by the grain structure of the film. However, in general, the surface of thin film magnetic media of magnetic recording disk which is process completed is protected by several-nm thick sputtered carbon. Therefore, high-resolution observation of a cross-sectional plane of a disk is strongly required to see the fine structure of the thin film magnetic media. Additionally, observation of the top protection film is also very important in this field.Recently, several different process-completed magnetic disks were examined with a UHR-SEM, the JEOL JSM 890, which consisted of a field emission gun and a high-performance immerse lens. The disks were cut into approximately 10-mm squares, the bottom of these pieces were carved into more than half of the total thickness of the disks, and they were bent. There were many cracks on the bent disks. When these disks were observed with the UHR-SEM, it was very difficult to observe the fine structure of thin film magnetic media which appeared on the cracks, because of a very heavy contamination on the observing area.


2009 ◽  
Vol 5 (H15) ◽  
pp. 401-401
Author(s):  
J. P. Pérez-Beaupuits ◽  
M. Spaans ◽  
M. Hogerheijde ◽  
R. Güsten

AbstractHigh resolution maps of the 12CO J = 6 → 5 line and the [C I]3P2 →3P1 (370 μm) fine-structure transition in the Galactic nebula M17 SW are presented. The maps were obtained using the dual color multiple pixel receiver CHAMP+ on the APEX† telescope.


Although the photosphere is a uniform region for scales greater than the granulation, the fact that the magnetic field strength falls off less sharply than the gas pressure leads to strong magnetic influence at greater heights in the solar atmosphere. This magnetic influence leads to non-uniformity and fine structure in the chromosphere and corona. The existence of such structure has been deduced mostly from measurements of photospheric phenomena; in particular, from measurements of photospheric velocity fields (Leighton, Noyes & Simon 1962) and of photospheric magnetic fields (Bumba & Howard 1965). The determining factor would thus appear to be in the photosphere; but visible effects only are produced in the chromosphere and corona. In recent years, high resolution filter photography has enabled us to recognize different regions of the chromosphere, where qualitatively different structure is associated with distinct magnetic field patterns. This progress has been possible because of better Lyot filters, better films and better observing sites; the spectroheliograph has always been limited for high resolution work by the finite slit width and the difficulty of accurate guiding during the long exposures.


In an earlier paper on the fine structures of the visible lines in the arc spectra of bromine and iodine an attempt was made to estimate the nuclear spin of iodine, and a tentative value of 9/2 was proposed. The iodine arc lines were excited by a high frequency electrodeless discharge in pure iodine vapour and examined with a silvered Fabry-perot interferometer. The fine structures in the arc lines are small, and as the patterns are highly complex and the individual components not very sharp, interpretation was difficult. It was concluded with certainty that the nuclear spin was at least equal to 5/2, but one line in particular suggested a value of 9/2. This was indefinite, and in view of the uncertainty a thorough examination of both the arc and spark spectra of iodine has been undertaken. A preliminary notice has already appeared. The first spark spectrum can be more easily studied than the arc spectrum, since the structure are on a very much bigger scale and more complete resolution can be attained. The present work is concerned with the spark lines excited in a hollow cathode discharge. Fine structures in iodine spark lines were first recorded long ago by Wood and Kimura who excited the lines in a Geissler tube and examined them with a transmission echelon. Murakawa attempted to analyse the fine structure data, but as the source and instrument employed by Wood and Kimura were not able to give the high resolution attained here, the deductions made from these data, although generally correct, are uncertain and require further examination; for many of the line structures are much more complex than as reported by these earlier observers.


1983 ◽  
Vol 270 ◽  
pp. L89 ◽  
Author(s):  
J. W. Cook ◽  
G. E. Brueckner ◽  
J.-D. F. Bartoe

2006 ◽  
Vol 24 (5) ◽  
pp. 1281-1293 ◽  
Author(s):  
R. Sheth ◽  
E. Kudeki ◽  
G. Lehmacher ◽  
M. Sarango ◽  
R. Woodman ◽  
...  

Abstract. Correlation studies performed on data from recent mesospheric experiments conducted with the 50-MHz Jicamarca radar in May 2003 and July 2004 are reported. The study is based on signals detected from a combination of vertical and off-vertical beams. The nominal height resolution was 150 m and spectral estimates were obtained after ~1 min integration. Spectral widths and backscattered power generally show positive correlations at upper mesospheric heights in agreement with earlier findings (e.g., Fukao et al., 1980) that upper mesospheric echoes are dominated by isotropic Bragg scatter. In many instances in the upper mesosphere, a weakening of positive correlation away from layer centers (towards top and bottom boundaries) was observed with the aid of improved height resolution. This finding supports the idea that layer edges are dominated by anisotropic turbulence. The data also suggests that negative correlations observed at lower mesospheric heights are caused by scattering from anisotropic structures rather than reflections from sharp vertical gradients in electron density.


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