Simultaneous ultrasonic velocity and sample thickness measurement and application in composites

1992 ◽  
Vol 92 (2) ◽  
pp. 669-675 ◽  
Author(s):  
David K. Hsu ◽  
Michael S. Hughes
Keyword(s):  
Ultrasonic Velocity ◽  
Thickness Measurement ◽  
Sample Thickness

Silicon Fringe Sample Metrology—A Thickness Measurement Technique

2013 ◽  
Author(s):  
Mark Kimball
Keyword(s):  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Measurement Technique ◽  
Thickness Measurement ◽  
Sample Thickness ◽  
Index Of Refraction ◽  
Interference Fringes ◽  
Noncontact Method ◽  
Thickness Variations

Abstract Silicon’s index of refraction has a strong temperature coefficient. This temperature dependence can be used to aid sample thinning procedures used for backside analysis, by providing a noncontact method of measuring absolute sample thickness. It also can remove slope ambiguity while counting interference fringes (used to determine the direction and magnitude of thickness variations across a sample).

Uncertainty Improvements of Metallic Resistivity Measurements by the Four-Point Probe Method

2006 ◽  
Vol 321-323 ◽  
pp. 1470-1474
Author(s):  
Kwang Min Yu ◽  
Jeon Hong Kang ◽  
Han Jun Kim ◽  
Kwon Soo Han ◽  
Je Cheon Ryu
Keyword(s):  
Electrical Resistivity ◽  
Measurement Uncertainty ◽  
Nondestructive Evaluation ◽  
Thickness Measurement ◽  
Sample Thickness ◽  
Probe Method ◽  
Resistivity Method ◽  
Plant Equipment ◽  
Thickness Measurements ◽  
Probe Spacing

Besides well-known destructive methods for material degradation, the electrical resistivity method has been used as one of nondestructive evaluation methods because of easy measurement. To use the method, however, careful geometrical corrections and thickness measurements are required. The high current probe assembly and accurate thickness measurement device were developed to improve overall measurement uncertainty. If dual configuration Four-Point Probe method with the developed devices is used, overall measurement uncertainty of electrical resistivity could be reduced to 0.44 % at 95 % confidence level. Proper selection of the probe spacing matched with sample thickness is very important to determine accurate electrical resistivity. When sample thickness is less than probe spacing, it is expected that dual configuration Four-Point Probe technique can be used in nondestructive evaluation of plant equipment materials.

Measurement of the Inelastic Mean Free Path by EELS Analyses of Submicron Spheres

1990 ◽  
Vol 48 (2) ◽  
pp. 74-75
Author(s):  
Laura A. Bonney
Keyword(s):  
Energy Loss ◽  
Free Path ◽  
Analytical Electron Microscopy ◽  
Mean Free Path ◽  
Thickness Measurement ◽  
Crystal Defects ◽  
Sample Thickness ◽  
Area Of Interest ◽  
Image Position ◽  
Inelastic Mean Free Path

Accurate measurement of sample thickness is important for analytical electron microscopy (AEM) but is often difficult and tedious. Unlike other thickness measurement methods, with electron energy loss spectroscopy (EELS) thickness may be measured in both amorphous and crystalline specimens and at the same location and orientation at which other data is collected in the electron microscope. Thickness values may be obtained from convergent-beam electron diffraction (CBED) data only if the sample is crystalline with large grains of uniform thickness. Sample thickness may be measured from crystal defects projected through the entire foil, but such defects are not always conveniently located in the area of interest. The distance between contamination spots on the upper and lower surfaces of the specimen may be measured, but this is not considered accurate and contamination is not desirable in microanalysis.Sample thickness t may be determined with EELS by the relation:(1)where It is the total intensity in the EEL spectrum, Iz is the intensity in the zero loss peak, and λ is the inelastic mean free path for energy loss of an incident electron in the sample.

scholarly journals THE ACCURACY OF ULTRASONIC THICKNESS MEASUREMENT OF DISTORTED GRAIN STRUCTURE METAL SAMPLES

2017 ◽  
Vol 45 (4) ◽  
pp. 33
Author(s):  
Nada Nađ ◽  
Morana Mihaljević ◽  
Zdenka Keran ◽  
Amalija Horvatić–Novak
Keyword(s):  
Ultrasonic Velocity ◽  
Metal Forming ◽  
Thickness Measurement ◽  
Grain Structure ◽  
Measurement Systems ◽  
The Third ◽  
Specific Direction ◽  
Measurement Results ◽  
Ultrasonic Thickness Measurement ◽  
Ultrasonic Thickness

Thickness measurement is one of the commonly used control measurements in sheet metal forming. Ultrasonic thickness measurement systems demand access to the material only from one side which makes them very useful for this purpose. Distortion of grain structure of the workpiece influences ultrasonic velocity and in that way directly influences ultrasonic thickness measurement. Three different ultrasonic thickness measurement systems are examined on the same working sample. Two systems are defined by standard EN14127. The third system is not defined by the standard and includes previously measured ultrasonic velocity in specific direction of grain elongation. Statistical analysis shows relations between measurement results obtained by all three systems and highlights the third system as the most accurate one.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 504-505
Author(s):  
John F. Mansfield ◽  
Douglas C. Crawford
Keyword(s):  
Electron Microscope ◽  
Video Camera ◽  
Thickness Measurement ◽  
Specimen Thickness ◽  
Crystalline Materials ◽  
Beam Dynamic ◽  
Line Measurement ◽  
On Line ◽  
Image Position ◽  
Convergent Beam

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:Where ξg, is the extinction distance for that reflection and ni is an integer.

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