A method to locate spatial distribution of scattering centers from ultrasonic backscatter signal

2019 ◽  
Vol 145 (4) ◽  
pp. 2453-2460
Author(s):  
Fang Chen ◽  
Aijun He ◽  
Sidong Fu ◽  
Xiaozhou Liu ◽  
Yunqing Liu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Backscatter Signal ◽  
Scattering Centers ◽  
Ultrasonic Backscatter

scholarly journals Flaw detection with ultrasonic backscatter signal envelopes

2019 ◽  
Vol 145 (2) ◽  
pp. EL142-EL148 ◽  
Author(s):  
Yongfeng Song ◽  
Christopher M. Kube ◽  
Zuoxiang Peng ◽  
Joseph A. Turner ◽  
Xiongbing Li
Keyword(s):  
Flaw Detection ◽  
Backscatter Signal ◽  
Ultrasonic Backscatter

scholarly journals Variability in Ultrasound Backscatter Induced by Trabecular Microstructure Deterioration in Cancellous Bone

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Xingxing Chou ◽  
Feng Xu ◽  
Ying Li ◽  
Chengcheng Liu ◽  
Dean Ta ◽  
...  
Keyword(s):  
Cancellous Bone ◽  
Fdtd Method ◽  
Bone Microstructure ◽  
Backscatter Coefficient ◽  
Backscatter Signal ◽  
Trabecular Microstructure ◽  
Ultrasound Backscatter ◽  
Ultrasonic Backscatter ◽  
The Relationship ◽  
Difference Time

To determine the relationship between the ultrasonic backscatter parameters and trabecular microstructural variations in cancellous bone, three erosion procedures were performed to simulate various changes in the cancellous bone microstructure. The finite difference time domain (FDTD) method was used to simulate the backscatter signal in cancellous bone. Ultrasonic backscatter properties were derived as functions of the porosity when the ultrasound incident directions were perpendicular and parallel to the major trabeculae direction (MTD), respectively. The variability in the apparent backscatter coefficient (ABC) and apparent integrated backscatter (AIB) due to the trabecular microstructure was revealed. Significant negative correlations between the backscatter parameters (ABC and AIB) and the porosity of the cancellous bone were observed. The simulations showed that the ABC and AIB were influenced by the direction of the trabecular microstructural variations. The linear regressions between the ultrasonic backscatter parameters (ABC and AIB) and the porosity showed significantly different slopes for three erosion procedures when they are ultrasonically perpendicular (for ABC, −1.22 dB, −0.98 dB, and −0.46 dB; for AIB, −0.74 dB, −0.69 dB, and −0.25 dB) and parallel (for ABC, −1.87 dB, −0.69 dB, and −0.51 dB; for AIB, −0.9 dB, −0.5 dB, and −0.34 dB) to the MTD. This paper investigated the relationship between ultrasonic backscatter and cancellous bone microstructure deterioration and indicated that the ultrasonic backscatter could be affected by cancellous bone microstructure deterioration direction.

scholarly journals Measurement and compensation of frequency-dependent attenuation in ultrasonic backscatter signal from cancellous bone

2019 ◽  
Vol 68 (18) ◽  
pp. 184301
Author(s):  
Rui Dong ◽  
Cheng-Cheng Liu ◽  
Xun-Bin Cai ◽  
Liu-Lei Shao ◽  
Bo-Yi Li ◽  
...  
Keyword(s):  
Cancellous Bone ◽  
Backscatter Signal ◽  
Frequency Dependent ◽  
Ultrasonic Backscatter

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

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.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

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