scholarly journals Effects of flat sweep frequency and pulsed ultrasound on the activity, conformation and microstructure of mushroom polyphenol oxidase

2022 ◽  
pp. 105908
Author(s):  
Baoguo Xu ◽  
Jianan Chen ◽  
Bimal Chitrakar ◽  
Hongyan Li ◽  
Jing Wang ◽  
...  
Keyword(s):  
Polyphenol Oxidase ◽  
Pulsed Ultrasound ◽  
Sweep Frequency

scholarly journals Preparation of tuna skin collagen-chitosan composite film improved by sweep frequency pulsed ultrasound technology

2021 ◽  
pp. 105880
Author(s):  
Wenjuan Qu ◽  
Tiantian Guo ◽  
Xinxin Zhang ◽  
Yuting Jin ◽  
Bo Wang ◽  
...  
Keyword(s):  
Composite Film ◽  
Pulsed Ultrasound ◽  
Sweep Frequency ◽  
Skin Collagen ◽  
Ultrasound Technology ◽  
Chitosan Composite

Record Wear Studies by Scanning Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 364-365
Author(s):  
M.D. Coutts ◽  
E.R. Levin ◽  
J.G. Woodward
Keyword(s):  
Electron Microscopy ◽  
Constant Velocity ◽  
Peak Velocity ◽  
Great Depth ◽  
Depth Of Focus ◽  
Sweep Frequency ◽  
Transmission Electron ◽  
Test Record ◽  
Lateral Mode ◽  
Scanning Electron

While record grooves have been studied by transmission electron microscopy with replica techniques, and by optical microscopy, the former are cumbersome and restricted and the latter limited by lack of depth of focus and resolution at higher magnification. With its great depth of focus and ease in specimen manipulation, the scanning electron microscope is admirably suited for record wear studies.A special RCA sweep frequency test record was used with both lateral and vertical modulation bands. The signal is a repetitive, constant-velocity sweep from 2 to 20 kHz having a duration and repetitive rate of approximately 0.1 sec. and a peak velocity of 5.5 cm/s.A series of different pickups and numbers of plays were used on vinyl records. One centimeter discs were then cut out, mounted and coated with 200 Å of gold to prevent charging during examination. Wear studies were made by taking micrographs of record grooves having 1, 10 and 50 plays with each stylus and comparing with typical “no-play” grooves. Fig. 1 shows unplayed grooves in a vinyl pressing with sweep-frequency modulation in the lateral mode.

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