scholarly journals A new reconstruction approach in diffraction ultrasound tomography: Combine transmission mode with reflection mode tomography

2010 ◽  
Vol 7 ◽  
pp. 51-56 ◽  
Author(s):  
Ning He ◽  
Jinxu Tao ◽  
Shijun Xua
Keyword(s):  
Transmission Mode ◽  
Reflection Mode ◽  
Ultrasound Tomography

Liquid Crystal Photonics: Optical Switching and Image Storage by Means of Azobenzene Liquid-Crystal Films

1996 ◽  
Vol 425 ◽  
Author(s):  
A. Shishido ◽  
O. Tsutsumi ◽  
T. Ikeda
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Optical Switching ◽  
Transmission Mode ◽  
Mode Analysis ◽  
Reflection Mode ◽  
Image Storage ◽  
Liquid Crystal Films ◽  
Crystal Films ◽  
One Year

AbstractOptical switching and image storage were explored by means of azobenzene liquid crystals (LCs). Azobenzene derivatives with monomeric and polymeric forms were prepared, which show nematic LC phase in the trans form while no LC phase in the cis form. On pulse irradiation at 355 nm, which causes trans-cis isomerization of the azobenzene moiety, these azobenzene LC films underwent nematic (N) to isotropic (1) phase transition in 100 ˜ 200 μs as probed by change in transmittance of a He-Ne laser through crossed polarizers (transmission-mode analysis) or change in reflectivity at the interface between the sample and glass substrate (reflection-mode analysis). In the reflection-mode analysis, the decay was faster than that observed in the transmission-mode analysis. The N phase recovered through the cis-trans thermal backisomerization process in the transmission-mode analysis, while it was restored through diffusion of the cis form, followed by reorientation of the trans form which replaced the cis form in the interface region, in the reflection-mode analysis. The photochemical N-I phase transition was also induced in 200 μs below Tg of the polymer azobenzene LC. Image could be stored into the polymer azobenzene LC film on photoirradiation to bring about the N-I phase transition and the stored image remained unchanged even after one year when it was kept below Tg of the polymer.

Arterial audiophotoplethysmography

Phlebologie ◽  
2003 ◽  
Vol 32 (03) ◽  
pp. 68-75
Author(s):  
B. Lambotte ◽  
C. El Gammal ◽  
V. Blazek ◽  
S. El Gammal
Keyword(s):  
Blood Pressure ◽  
Systolic Pressure ◽  
Arterial Disease ◽  
Transmission Mode ◽  
Reflection Mode ◽  
Pressure Cuff ◽  
Significant Difference ◽  
Peripheral Arterial ◽  
Audio Output

SummaryBackground: Digital blood pressure is an important prognostic parameter in peripheral arterial disease. However, it is rarely determined in clinical routine because the methods available are too cumbersome. Patients and methods: Arterial audiophotoplethysmography (APPG) uses an in-built audio output. The systolic pressure corresponds to the reappearance of a pulssynchrone beep during deflation of the pressure cuff (25 mm wide on fingers and toes) after suprasystolic inflation. Measurements can be performed either in transmission or reflection mode. 50 healthy volunteers (age: 23-75 years) were examined in supine position. Blood pressure was taken at the A. brachialis, A. ulnaris, A. radialis, A. poplitea, A. tibialis anterior and posterior using ultrasound Doppler (USD), at the A. brachialis, fingers 1-5, A. poplitea and toes 1-3 using APPG. Results: Regarding the A. brachialis and poplitea, we found an excellent correlation between values obtained by USD and APPG in transmission mode (r: 0.92-0.99), the correlation with the reflection mode-values was slightly lower (r: 0.81- 0.93). The values obtained in reflection mode were significantly lower than in transmission mode (average 5.2 mmHg on the arms, 12.9 mmHg on the legs). Finger pressure was identical with A. brachialis-pressure. Toe/- brachial index was 0.81-0.86 (transmission) and 0.72- 0.78 (reflection). No significant difference was found between any of the fingers, respectively the toes. Conclusions: APPG is a reliable method for determination of digital blood pressure, which can be easily performed. Measurements in transmission mode should be preferred.

Geometrical factors for correction of intensities in Seemann–Bohlin diffractometry

1993 ◽  
Vol 8 (1) ◽  
pp. 7-13
Author(s):  
R. Černý ◽  
V. Kupčík
Keyword(s):  
Titanium Nitride ◽  
Measured Data ◽  
Transmission Mode ◽  
Reflection Mode ◽  
Final Test ◽  
Detector Distance ◽  
Geometrical Factors ◽  
Nitride Layers ◽  
Mode A ◽  
Variable Efficiency

The correct formulas for geometrical factors for correction of diffracted intensities in Seemann-Bohlin diffractometry were tested. A Huber 653 goniometer, gold and titanium nitride layers, white tin, and rutile as specimens were used in the reflection mode. A Huber 642 goniometer and olivine as a specimen were used in the transmission mode. It was found that, due to a variable specimen-detector distance during 2θ scan, the variable efficiency of the Soller slits in the diffracted beam must be taken into account. The model describing this effect analytically is presented. As a final test the structures of white tin, rutile, and olivine were refined from the measured data corrected for different factors.

An improved design for an Scanning Tunnelling Microscope (STM) for use in a Transmission Electron Microscope (TEM)

1991 ◽  
Vol 49 ◽  
pp. 384-385
Author(s):  
W.K. Lo ◽  
J.C.H. Spence
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Mechanical Stability ◽  
Scanning Tunnelling Microscope ◽  
Reflection Mode ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Improved Design

An improved design for a combination Scanning Tunnelling Microscope/TEM specimen holder is presented. It is based on earlier versions which have been used to test the usefulness of such a device. As with the earlier versions, this holder is meant to replace the standard double-tilt specimen holder of an unmodified Philips 400T TEM. It allows the sample to be imaged simultaneously by both the STM and the TEM when the TEM is operated in the reflection mode (see figure 1).The resolution of a STM is determined by its tip radii as well as its stability. This places strict limitations on the mechanical stability of the tip with respect to the sample. In this STM the piezoelectric tube scanner is rigidly mounted inside the endcap of the STM holder. The tip coarse approach to the sample (z-direction) is provided by an Inchworm which is located outside the TEM vacuum.

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