A direct investigation of lattice relaxation at a crystal surface by optical transforms of surface profile images

1989 ◽  
Vol 22 (6) ◽  
pp. 592-600 ◽  
Author(s):  
J. Harada ◽  
M. Takata ◽  
H. Miyatake ◽  
H. Koyama
Keyword(s):  
Crystal Surface ◽  
Surface Profile ◽  
Lattice Relaxation ◽  
Optical Diffraction ◽  
Wafer Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Surface Modulation ◽  
Diffraction Patterns

Rod-shaped scattering, referred to as crystal truncation rod (CTR) scattering in X-ray diffraction, can also be observed in optical diffraction patterns obtained from the surface profile image of high-resolution electron micrographs. The characteristics of the CTR scattering are shown to be in agreement with those observed by X-ray scattering. With this technique, information about the lattice relaxation of the image of surfaces or interface boundaries observed in the electron microscope (EM) can be easily obtained and the lattice spacing of a GaAs crystal is shown to be shrunk at the interface boundary between the (001) surface and the amorphous oxide layer. This is precisely opposite to the effect observed for an Si (001) wafer surface. Several effects of surface modulation on CTR scattering are demonstrated using an optical diffractometer and masks of the f.c.c. lattice.

Optical diffraction studies of myofibrillar structure

1971 ◽  
Vol 261 (837) ◽  
pp. 201-208 ◽  
Keyword(s):  
Electron Micrographs ◽  
Focal Length ◽  
Optical Diffraction ◽  
Myofibrillar Proteins ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
Optical Filtering ◽  
X Ray ◽  
The Subject ◽  
Diffraction Patterns

We have used the techniques of optical diffraction and optical filtering to study electron micrographs of myofibrils and of paracrystals of myofibrillar proteins. The optical diffraction patterns provide information about periodic structure in the micrographs, and sometimes may reveal periodicities not apparent to the eye. We compare the optical diffraction patterns with the X-ray diffraction patterns obtained from living muscle, and this comparison can assist our interpretation of both the X-ray diffraction patterns and the electron micrographs. The optical diffractometer we have used is essentially similar to those described by Taylor & Lipson (1964), and by Klug & DeRosier (1966). The apparatus incorporates several refinements to facilitate operation. The recombining lens has a focal length, f , of about 1 m, and is placed so that the recombined image is formed at 2 f and has the same size as the subject. The diffraction subjects are not usually the electron micrographs themselves but copies on film. The film is of more uniform optical thickness than the glass electron micrograph, and is less fragile. Moreover, a set of films of varying contrast can be made from one micrograph.

scholarly journals An electron microscopic and optical diffraction analysis of the structure of Limulus telson muscle thick filaments.

1982 ◽  
Vol 92 (2) ◽  
pp. 443-451 ◽  
Author(s):  
R W Kensler ◽  
R J Levine
Keyword(s):  
Electron Microscopy ◽  
Diffraction Analysis ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Cross Bridges

Long, thick filaments (greater than 4.0 micrometer) rapidly and gently isolated from fresh, unstimulated Limulus muscle by an improved procedure have been examined by electron microscopy and optical diffraction. Images of negatively stained filaments appear highly periodic with a well-preserved myosin cross-bridge array. Optical diffraction patterns of the electron micrographs show a wealth of detail and are consistent with a myosin helical repeat of 43.8 nm, similar to that observed by x-ray diffraction. Analysis of the optical diffraction patterns, in conjunction with the appearance in electron micrographs of the filaments, supports a model for the filament in which the myosin cross-bridges are arranged on a four-stranded helix, with 12 cross-bridges per turn or each helix, thus giving an axial repeat every third level of cross-bridges (43.8 nm).

Three-dimensional optical transforms

1961 ◽  
Vol 264 (1318) ◽  
pp. 339-354 ◽  
Keyword(s):  
Fourier Transforms ◽  
Three Dimensional ◽  
Polarized Light ◽  
Continuous Phase ◽  
Optical Diffraction ◽  
X Ray Diffraction ◽  
Circularly Polarized Light ◽  
X Ray ◽  
Half Wave ◽  
Diffraction Patterns

In recent years optical diffraction patterns have been used to assist in the solution of certain X-ray diffraction problems. The most useful technique—which is based partly on the properties of Fourier transforms and partly on optical experiments—is usually known as the optical-transform technique. It has, however, so far been confined to problems involving the projection of crystal structures on to a plane. The present work is aimed at extending the application to full three-dimensional structures. It is shown that this is most simply achieved by controlling the relative phases of beams of light; a method of phase control using circularly polarized light and half-wave plates of mica is described. The theory of the method, experimental details, and the demonstration of its validity are given. In order to gain experience in the use of three-dimensional optical transforms for solving X-ray diffraction problems a known structure has been examined, and the results of this work are included. Although this work has been primarily concerned with applications to X-ray diffraction, it is thought that the method of continuous phase changing, which is simple and linear, may find uses in other fields.

Interfacial reaction products and film orientation in YBa2Cu3O7−x on zirconia substrates with and without CeO2 buffer layers

1993 ◽  
Vol 8 (11) ◽  
pp. 2785-2798 ◽  
Author(s):  
G.L. Skofronick ◽  
A.H. Carim ◽  
S.R. Foltyn ◽  
R.E. Muenchausen
Keyword(s):  
Interfacial Reaction ◽  
High Resolution Electron Microscopy ◽  
Buffer Layers ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
Resolution Electron ◽  
Ybco Superconductors ◽  
Diffraction Patterns

Thick film (1.2 μm) YBCO superconductors grown by pulsed laser deposition on unbuffered and CeO2-buffered single crystal (001)-oriented yttria-stabilized zirconia (YSZ) substrates have been investigated. YBCO and YSZ react to form BaZrO3 (BZO), whereas YBCO and CeO2 react to form BaCeO3. Reaction phases were examined by θ-2θ and four-circle x-ray diffraction and high resolution electron microscopy. Three orientation relationships identified for the unbuffered films were (i) (001)YBCO ‖ (011)BZO ‖ (001)YSZ with [110]YBCO ‖ [100]BZO ‖ [100]YSZ, (ii) (001)YBCO ‖ (001)BZO ‖ (001)YSZ with [110]YBCO ‖ [100]BZO ‖ [100]YSZ, and (iii) (001)YBCO ‖ (001)BZO ‖ (001)YSZ with [100]YBCO ‖ [100]BZO ‖ [100]YSZ. The results suggest that for films grown at typical deposition temperatures, YBCO epitaxy is established before the interfacial reaction occurs. The presence of BaCeO3 in buffered films grown at high temperatures (790 °C) was confirmed by θ-2θ scans and selected area diffraction patterns.

scholarly journals Frog skeletal muscle thick filaments are three-stranded.

1983 ◽  
Vol 96 (6) ◽  
pp. 1797-1802 ◽  
Author(s):  
R W Kensler ◽  
M Stewart
Keyword(s):  
Skeletal Muscle ◽  
Optical Diffraction ◽  
Layer Line ◽  
X Ray Diffraction ◽  
Computer Image Analysis ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Meridional Reflection ◽  
Vertebrate Skeletal Muscle

A procedure has been developed for isolating and negatively staining vertebrate skeletal muscle thick filaments that preserves the arrangement of the myosin crossbridges. Electron micrographs of these filaments showed a clear periodicity associated with crossbridges with an axial repeat of 42.9 nm. Optical diffraction patterns of these images showed clear layer lines and were qualitatively similar to published x-ray diffraction patterns, except that the 1/14.3-nm meridional reflection was somewhat weaker. Computer image analysis of negatively stained images of these filaments has enabled the number of strands to be established unequivocally. Both reconstructed images from layer line data and analysis of the phases of the inner maxima of the first layer line are consistent only with a three-stranded structure and cannot be reconciled with either two- or four-stranded models.

Crystal Structures Of L-Nb205 AND L-Ta205

1977 ◽  
Vol 35 ◽  
pp. 188-189
Author(s):  
Sumio Iijima
Keyword(s):  
Electron Microscope ◽  
Complex Nature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Unit Cells ◽  
System 2 ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Phase Relationships

Although structures of tantalum pentoxides have been extensively studied, they have not been fully understood because of the complex nature of their X-ray diffraction patterns. In this study we made some observations on crystals of L-Ta2O5 and L-Nb2O5 using a high resolution electron microscope. The latter structure has been believed to be isostructural with L-Ta2O5. The samples were prepared by Dr. Roth at NBS and were parts of the products used for determining phase relationships in niobium pentoxides (1) and the Ta2O5-Ta2WO8 system (2).According to the X-ray data both structures have orthorhombic unit cells with a = 6.2, b = 29.3, c = 3.9Å. The structures are based on the U03-type and the b spacings are nearly 8 times those of the subcell. Electron diffraction (E.D.) patterns of L-Nb2O5 and L-Ta3O5 crystals showing a*-b* reciprocal sections confirmed generally the results of X-ray works (Figs, la and lc).

Structure determination of inorganic structures by HREM, Cip, and electron diffraction

1993 ◽  
Vol 51 ◽  
pp. 1204-1205
Author(s):  
Xiaodong Zou ◽  
V.G. Zubkov ◽  
Gunnar Svensson ◽  
Sven Hovmöller
Keyword(s):  
Image Processing ◽  
Electron Diffraction ◽  
Ccd Camera ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Diffraction Patterns ◽  
The Fourier Transform

High resolution electron microscopy (HREM) combined with crystallographic image processing (CIP) is becoming a powerful technique for solving inorganic structures. With the image processing systems CRISP and ELD, running on a personal computer, this technique can be easily established in other laboratories. HREM images and electron diffraction patterns are digitized by a CCD camera and transferred into a PC. Phases and amplitudes are extracted from the Fourier transform of the HREM images. For thin crystals of metal oxides, the phases obtained by HREM and CIP inside the Scherzer resolution of the microscope are identical to the x-ray structure factor phases.Electron diffraction extends to much higher resolution than EM images (beyond 1 Å). The quality of the amplitudes is also higher than that from images, since ED data is not affected by the contract transfer function (CTF). Amplitudes extracted by ELD are close to x-ray diffraction amplitudes (within 30%).

Development of an in-situ X-ray diffraction system for observation of electrodeposition of metallic layers

1998 ◽  
Vol 5 (3) ◽  
pp. 935-936 ◽  
Author(s):  
Muneyuki Imafuku ◽  
Masao Kurosaki ◽  
Koichi Kawasaki
Keyword(s):  
Crystal Surface ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Image Plate ◽  
Initial Stage ◽  
Diffraction Patterns ◽  
Dynamic Phenomena ◽  
A Current

In order to study the dynamic phenomena of electrodeposition of metallic layers, an in situ X-ray diffraction system has been newly developed using an electrochemical cell and an image-plate detector. Electrodeposition of Zn on an Fe(100) single-crystal surface with a current density at 0.5 A cm−2 was demonstrated in this study. Time-resolved diffraction patterns were obtained by scanning the image plate. It was found that Zn(101) layers were mainly formed from the initial stage of deposition and grew continuously on this substrate. Growth of other layers, such as Zn(103), Zn(110) and Zn(102), were also detected. On the other hand, Zn(100) and Zn(002) were not observed under this condition.

Identification of a new trace 114R SiC by HREM

1999 ◽  
Vol 55 (2) ◽  
pp. 255-257 ◽  
Author(s):  
X. Y. Yang ◽  
G. Y. Shi ◽  
X. M. Meng ◽  
H. L. Huang ◽  
Y. K. Wu
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Matrix Model ◽  
High Resolution Electron Microscopy ◽  
Stacking Sequence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Diffraction Patterns

Using electron diffraction patterns and high-resolution electron microscopy (HREM), a trace 114R SiC in commercial α-SiC powder (mainly 6H SiC according to X-ray diffraction) has been discovered. In a hexagonal unit cell its stacking sequence is [(33)4(34)2]3, the periodicity along the c axis is 286.14 Å and a = b = 3.073 Å. 114R belongs to the structure series of (33) n34(33) m34 predicted theoretically by Pandey & Krishna [Mater. Sci. Eng. (1975), 20, 243–249] on the basis of the faulted matrix model.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

Sign in / Sign up

Export Citation Format

Share Document