Transparent Area Washing Systems for Aircraft

2011 ◽  
Author(s):  
Keyword(s):  
Transparent Area

A Polishless Method For Preparation Of Cross-Sectional Tem Samples

1987 ◽  
Vol 115 ◽  
Author(s):  
J. T. Wetzel ◽  
D. A. Danner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Beam ◽  
Ease Of Use ◽  
Traditional Methods ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Lift Off ◽  
Materials Used ◽  
Transparent Area

ABSTRACTCross-sectional samples for Transmission Electron Microscopy (TEM) have been made without the use of mechanical polishing and ion beam milling. Instead of traditional methods, we have used a combination of electron beam (e-beam) lithography for metal lift-off and reactive ion etching (RIE) to produce TEM samples of selected areas. The sample integrity for handling, dropping and ease of use is excellent, and the large amount of transparent area available for study is nearly 2 orders of magnitude larger than that given by traditional methods. The thickness of the samples is somewhat extreme, on the order of 0.50–1.0μm, but efforts are being made to reduce this dimension in order to make the method applicable to the whole range of materials used in silicon technology.

An Advanced Mechanical Dimpung Technique for the Preparation of TEM Specimens

1990 ◽  
Vol 199 ◽  
Author(s):  
Paul E. Fischione ◽  
James M. Howe
Keyword(s):  
Electron Beam ◽  
Ion Milling ◽  
Cross Sectional ◽  
New Instrumentation ◽  
Mechanical Thinning ◽  
Transparent Area ◽  
Layered Samples

ABSTRACTFor materials that are conducive to pre-thinning by mechanical techniques, a combination of dimpling and ion milling is commonly employed to produce TEM specimens. In order to minimize artifacts induced by ion milling and to provide an increased electron-beam transparent area, new instrumentation for mechanical thinning has been developed. Examples illustrating the utilization of this instrument in the preparation of cross-sectional interfaces from layered samples are discussed.

Misfit dislocations in heteroepitaxial systems with low dislocation density

1978 ◽  
Vol 36 (1) ◽  
pp. 132-133
Author(s):  
W. Hagen ◽  
H. Strunk
Keyword(s):  
Electron Microscopy ◽  
Dislocation Density ◽  
Misfit Dislocations ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Transmission Electron ◽  
Low Dislocation Density ◽  
Heteroepitaxial Layers ◽  
Transparent Area ◽  
Electron Transparent Area

The growth of heteroepitaxial layers causes stress across the interface which in a certain range of layer thickness may he relaxed by the formation of misfit dislocations at the interface. Systematic investigations of such misfit structures by transmission electron microscopy (TEM) have previously heen conducted only on systems with a relatively large misfit parameter f, i.e. with a high dislocation density. However, this case presents difficulties in the analysis because of the complexity of the dense structures.Interfaces containing a low density of misfit dislocations, e.g. heteroepitaxial systems with low misfit, should consequently be investigated. High voltage electron microscopy (HVEM) enables us to study specimens of several μm in thickness and offers decisive advantages over 100 kV TEM: i) generally, specimens can he prepared by thinning the substrate only, ii) thick foils are mechanically stable, which allows the preparation of specimens with an electron transparent area of several mm2.We report here new results on the initial formation of misfit dislocation structures in the heteroepitaxial system Ge on GaAs (f = 0.074%).

HREM applications to industrial products: Observation of thick-film resistors with very large electron transparent area

1992 ◽  
Vol 50 (1) ◽  
pp. 140-141
Author(s):  
Z.G. Li ◽  
P.F. Carcia ◽  
P. Donohue
Keyword(s):  
Thick Film ◽  
Semiconductor Industry ◽  
Milling Process ◽  
Ion Milling ◽  
Secondary Support ◽  
Characterization Of Materials ◽  
Transparent Area ◽  
Electron Transparent Area ◽  
Section Sample

HRTEM is a very powerful tool for structural characterization of materials. However, its role in industry is still very limited and electron microscopy is generally considered as a secondary support technique, although it can uniquely provide microstructural information leading to understanding and improvement of product quality, especially for those materials in the form of films. An example in the semiconductor industry is recendy described by Anderson. He points out that the main concerns of imaging using a conventional cross-section sample preparation method are too small imaged areas, not representative of the product, and artifacts that may be introduced during the ion-milling process. Here we apply HREM to thick film resistors and attempt to overcome these obstacles.

An improved dimpling technique for the preparation of TEM specimens

1990 ◽  
Vol 48 (4) ◽  
pp. 874-875
Author(s):  
P.E. Fischione ◽  
J.M. Howe ◽  
A. Garg
Keyword(s):  
Milling Time ◽  
Ion Beam ◽  
Specimen Thickness ◽  
Trial And Error ◽  
Intervention Trial ◽  
Ion Milling ◽  
Advanced Technique ◽  
Precise Positioning ◽  
New Device ◽  
Transparent Area

Traditional techniques for the preparation of TEM specimens have been electrolytic thinning or a combination of mechanical prethinning (dimpling) and ion-beam milling. The focus of discussion for this paper is an advanced technique for the mechanical dimpling procedure.A new device has been designed so that TEM specimens are consistently produced, thus minimizing the need for intensive operator intervention, trial and error methods, and ion-milling time. This instrument incorporates many of the features utilized in standard dimpling techniques. In addition, it provides the ability to simultaneously rotate and oscillate the specimen, resulting in an increased electron beam transparent area. Actual grinding rates are programmed with a resolution of 0.1 μ.m/min, thus eliminating the reliance on adjustable counterweight systems to control the grinding rate/force. A 40X microscope and movable magnetic specimen mount permit precise positioning that enables the dimple to be located at any point on the specimen. This is illustrated in Fig. 3, where the dimple is positioned on the interface of interest. An integral lamp back lights the specimen so that transparency can be detected without removing the specimen from the instrument. During the preparation process, the actual specimen thickness is continuously indicated on an alphanumeric display.

Preparation of Cross Sectional TEM Samples Using Lithographic Techniques and Reactive Ion Etching

1990 ◽  
Vol 199 ◽  
Author(s):  
Jeffrey T. Wetzel ◽  
K. L. Kavanagh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reactive Ion Etching ◽  
Limited Range ◽  
Ion Milling ◽  
Cross Sectional ◽  
Ion Etching ◽  
Lithographic Patterning ◽  
Transmission Electron ◽  
Transparent Area

ABSTRACTThis paper summarizes methods used to create cross-sectional samples for transmission electron microscopy and introduces another variant of the technique all of which rely upon some combination of lithographic patterning and reactive ion etching. The basic idea pursued in using these techniques was to form, from a preselected location, samples that had a large transparent area without use of mechanical polishing or ion milling. Samples were successfully prepared in this manner, but room for improvement remains due to the limited range of diffraction conditions available for imaging or diffraction pattern formation.

Characteristic cytoplasmic structures in microorganisms utilizing n-butane and 1-butanol

1974 ◽  
Vol 20 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Agnes C. Kormendy ◽  
Morris Wayman
Keyword(s):  
Electron Transport ◽  
Transport System ◽  
Candida Utilis ◽  
Alcohol Oxidation ◽  
Sole Source ◽  
Dense Bodies ◽  
Cytoplasmic Structures ◽  
Electron Carriers ◽  
Transparent Area ◽  
Electron Transparent Area

Intracellular structures were observed in two Arthrobacter spp. and in Candida utilis in media containing n-butane or 1-butanol as the sole source of carbon; these structures were absent in the same organisms grown in the presence of glucose. These substrate-specific structures consisted of electron-dense bodies nearly surrounded by a round electron-transparent area, and connected to the main cytoplasm by a bridge. These structures may represent sites of hydrocarbon or alcohol oxidation, and the name "oxisome" is proposed for them. The microorganisms contained about 8 times as much iron when growing on n-butane as when growing on glucose, and about 3 to 4.5 times as much when growing on 1-butanol. When one of the Arthrobacter sp. was grown on n-butane in the absence of iron, more diffuse and less structured concentrations of electron-dense particles appeared. Extraction of n-butane-grown cells suggests that the electron transport system is different from other known electron carriers.

scholarly journals Self-focusing limits at the laser-plasma interaction for treatment of cataract with nanosecond and picosecond pulses

1992 ◽  
Vol 10 (1) ◽  
pp. 163-178 ◽  
Author(s):  
Rosemarie H. Hora ◽  
Hans G. L. Coster ◽  
Clement J. Walter ◽  
Heinrich Hora
Keyword(s):  
Optical Breakdown ◽  
Laser Pulses ◽  
The Self ◽  
Laser Beams ◽  
Temperature Plasma ◽  
Picosecond Pulses ◽  
Laser Plasma Interaction ◽  
Self Focusing ◽  
Nanosecond Range ◽  
Transparent Area

Laser pulses are focused in the interior of a human eye in areas of opacity to produce there an optical breakdown resulting in a high-temperature plasma, after which the filling up with liquid results in a transparent area. The empirically given limits for Q-switch laser pulses in the nanosecond range and for mode-locked pulses in the picosecond range are analyzed, and it is shown that these limits are below the self-focusing condition of laser beams in plasmas. A further analysis evaluates theoretically where the maximum limits are given in order to provide the parameters for the highest possible pulse energy that avoids damage in the eye by self-focusing.

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