Study of thin smectic A samples by a photoacoustic technique

1986 ◽  
Vol 64 (9) ◽  
pp. 1230-1233 ◽  
Author(s):  
G. Louis ◽  
P. Peretti ◽  
J. Billard ◽  
B. Mangeot
Keyword(s):  
Phase Transitions ◽  
Liquid Crystal ◽  
Thermal Diffusivity ◽  
Modulation Frequency ◽  
Rear Surface ◽  
Photoacoustic Signal ◽  
Sample Thickness ◽  
Photoacoustic Technique ◽  
Smectic A

First we recall some experimental results about phase transitions in a thermotropic liquid crystal investigated by means of a photoacoustic technique. Then this paper examines the photoacoustic signal as a function of the sample thickness and the modulation frequency for rear-surface illumination of the smectic A sample. The results are consistent with the McDonald and Wetsel model and lead to the determination of thermal diffusivity.

STUDY OF THERMAL TRANSPORT PARAMETERS IN PbI2 SINGLE CRYSTAL USING A PHOTOACOUSTIC TECHNIQUE

2006 ◽  
Vol 20 (20) ◽  
pp. 1253-1260 ◽  
Author(s):  
D. S. AHLAWAT ◽  
D. MOHAN ◽  
S. K. GHOSHAL ◽  
R. D. SINGH ◽  
MEENAKSHI SHARMA
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Single Crystal ◽  
Characteristic Frequency ◽  
Modulation Frequency ◽  
Thermal Effusivity ◽  
Photoacoustic Signal ◽  
Photoacoustic Technique ◽  
Front Side ◽  
Transport Parameters

The present work discusses the study of the transport properties of the PbI 2 single crystal using an indigenously developed photoacoutistic spectrometer. The amplitude photoacoustic signal, being a function of the modulation frequency of the incident optical beam, has been measured by using the front-side detection configuration. The characteristic frequency (fc) of the single crystal has been found to be 55 Hz. The values of thermal diffusivity, thermal conductivity and thermal effusivity in the case of PbI 2 have been derived experimentally. Their values have been compared with the values reported in a case which studied other materials in the literature. Thermal diffusion lengths have also been calculated at different chopping frequencies from 15 Hz to 90 Hz.

Phase diagram, fluctuations, and phase transitions near the liquid-crystal nematic–smectic-A–smectic-Cmulticritical point

1987 ◽  
Vol 36 (5) ◽  
pp. 2372-2383 ◽  
Author(s):  
L. J. Martínez-Miranda ◽  
A. R. Kortan ◽  
R. J. Birgeneau
Keyword(s):  
Phase Diagram ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Smectic A

Determination of the Coefficients in Landau Free Energy near the Smectic-A-Chiral Smectic-C Transition for the Liquid Crystal MBRA8

1984 ◽  
Vol 108 (1-2) ◽  
pp. 149-155 ◽  
Author(s):  
S. C. Lien ◽  
C. C. Huang ◽  
T. Carlsson ◽  
I. Dahl ◽  
S. T. Lagerwall
Keyword(s):  
Free Energy ◽  
Liquid Crystal ◽  
Smectic A ◽  
Smectic C ◽  
Landau Free Energy

Simultaneous heat capacity and thermal-diffusivity photoacoustic measurement at liquid-crystal phase transitions

1987 ◽  
Vol 9 (7) ◽  
pp. 855-862 ◽  
Author(s):  
M. Marinelli ◽  
U. Zammit ◽  
F. Scudieri ◽  
S. Martellucci ◽  
F. Bloisi ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Thermal Diffusivity ◽  
Crystal Phase ◽  
Liquid Crystal Phase ◽  
Photoacoustic Measurement ◽  
Simultaneous Heat

Dependence of the X-Ray Photoacoustic Signal Intensity of Brass on Sample Thickness and Modulation Frequency

1992 ◽  
Vol 31 (Part 1, No. 8) ◽  
pp. 2648-2649 ◽  
Author(s):  
Taro Toyoda ◽  
Tsutomu Masujima ◽  
Hideaki Shiwaku ◽  
M. Ando
Keyword(s):  
Signal Intensity ◽  
Modulation Frequency ◽  
Photoacoustic Signal ◽  
Sample Thickness ◽  
X Ray
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