Accurate measurement of the temperature coefficient of the ultrasonic velocity of fused quartz near room temperature

1987 ◽  
Vol 58 (9) ◽  
pp. 1758-1761 ◽  
Author(s):  
S. E. Chen ◽  
Steven W. Meeks ◽  
George C. Johnson ◽  
Andrew C. Tam
Keyword(s):  
Temperature Coefficient ◽  
Ultrasonic Velocity ◽  
Room Temperature ◽  
Fused Quartz

scholarly journals Ferrite-based room temperature negative temperature coefficient printed thermistors

2020 ◽  
Vol 56 (24) ◽  
pp. 1322-1324
Author(s):  
J.R. McGhee ◽  
J.S. Sagu ◽  
D.J. Southee ◽  
P.S.A. Evans ◽  
K.G.U. Wijayantha
Keyword(s):  
Temperature Coefficient ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature

A RECORDING VACUUM THERMOBALANCE

1957 ◽  
Vol 35 (4) ◽  
pp. 374-380 ◽  
Author(s):  
J. G. Hooley
Keyword(s):  
Temperature Coefficient ◽  
Maximum Sensitivity ◽  
Weight Changes ◽  
Dimensional Changes ◽  
Spring Balance ◽  
Fused Quartz

A recording quartz spring balance is described, with which weight changes up to 1000 mg. can be followed linearly on a millivolt recorder for samples weighing up to 10 g. During the recording operation the sample may be under vacuum or pressure and may be heated or cooled. The maximum practical sensitivity is about 20 millivolts per milligram and the over-all error in reading the record is about 1 millivolt. The temperature coefficient of fused quartz springs is reported to be − (1.25 ± 0.02) × 10−4 per degree centigrade in the range 20° to 35 °C.The device could be readily adapted for heavier loads and greater weight changes by using less sensitive springs and could be used for measuring dimensional changes of solids with a maximum sensitivity of at least 2000 mv. per millimeter.

Deposition of Thin Films of Silicon Carbide on Fused Quartz and on Sapphire by Laser Ablation of Ceramic Silicon Carbide Targets

1992 ◽  
Vol 285 ◽  
Author(s):  
L. Rimai ◽  
R. Ager ◽  
J. Hangas ◽  
E. M. Loaothetis ◽  
Nayef Abu-ageel ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Fused Silica ◽  
High Resistivity ◽  
Fused Quartz ◽  
Amorphous Sic ◽  
Very High

ABSTRACTAblation of ceramic silicon carbide with 351 nm excimer radiation was used to depositSIC films on fused silica and on sapphire. For deposition temperatures above 850° C, diffraction shows the films to be crystalline with the [111] axis preferentially oriented normally to the film. Optical spectra show an indirect energy gap at 2.2 eV, near that for the cubic polytype, although the 200 diffractions are absent. Room temperature resistivities range between .02 to .1 Ωcm. Deposition below 600° C yields amorphous SiC with no diffraction bands, low and variable optical band gap and very high resistivity.

Temperature Variation of Principal Moments of Some Polyatomic Crystals

1973 ◽  
Vol 28 (1-2) ◽  
pp. 23-25 ◽  
Author(s):  
O. P. Singhal
Keyword(s):  
Solid State ◽  
Temperature Coefficient ◽  
Single Crystals ◽  
Air Temperature ◽  
Entire Range ◽  
Room Temperature ◽  
Small Variation ◽  
Potassium Chromate ◽  
Absorption Frequency ◽  
Ammonium Dichromate

Principal moments of some of the polyatomic single crystals such as ammonium dichromate, ammonium chromate, potassium chromate and potassium permanganate have been determined from room temperature down to liquid air temperature. These have been found to decrease with the decrease of temperature. This variation is smaller in magnitude. It has been observed that the temperature coefficient of the principal moments has almost the same value over the entire range of temperature. This small variation of paramagnetism has been attributed to the variation of absorption frequency in solid state.

scholarly journals The Room Temperature Elastic Behaviour of CsH2PO4

1985 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
S Prawer ◽  
TF Smith ◽  
TR Finlayson
Keyword(s):  
Elastic Constant ◽  
Young’S Modulus ◽  
Ultrasonic Velocity ◽  
Room Temperature ◽  
Elastic Anisotropy ◽  
Elastic Behaviour ◽  
Dihydrogen Phosphate ◽  
Velocity Measurements ◽  
Constant Matrix ◽  
Linear Compressibility

The components of the elastic constant matrix of monoclinic caesium dihydrogen phosphate (CDP) have been determined using ultrasonic velocity measurements to be Cl1 = 28� 83 � 0 '43, C22 = 26�67 � O� 37, C33 = 65 �45 � 0'48, C44 = 8 .1O� 0,15, Css = 5 �20� 0,24, C66 = 9�17 � 0,22, C12 = 1l'4�3'6, C13 = 42�87�1�58, CIS = 5'13�0'67, C23 = 14�5�4�4, C 2S = 8'4�4'3, C3S = 7�50�0�81 and C46 = -2�25�0�31 GPa. Calculations of the velocity surfaces, ray directions, Young's modulus surfaces and linear compressibility show marked elastic anisotropy, which has been correlated with the chain and layer-like structure of CDP.

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