Lorentz–Lorenz Coefficient of Ethane

1974 ◽  
Vol 52 (20) ◽  
pp. 2011-2013 ◽  
Author(s):  
M. Burton ◽  
D. Balzarini
Keyword(s):  
Critical Density ◽  
Index Of Refraction ◽  
Density Range

The index of refraction of ethane at 6328 Å has been measured in the density range 0.02 to 0.36 g/cm3(1 to 200 amagats). The coefficient in the Lorentz–Lorenz expression [Formula: see text] is constant to within 0.5% for the temperature and density range studied. The coefficient [Formula: see text] increases with density reaching a maximum near the critical density and decreases with density for densities larger than the critical density. The critical density has been measured in the same experiment and is 0.2062 ± 0.0003 g/cm3.

Critical constants and density dependence of the Lorenz–Lorentz coefficient for germane

1978 ◽  
Vol 56 (9) ◽  
pp. 1140-1141 ◽  
Author(s):  
P. Palffy-Muhoray ◽  
D. Balzarini
Keyword(s):  
Critical Temperature ◽  
Density Dependence ◽  
Experimental Error ◽  
Critical Density ◽  
Coexistence Curve ◽  
Index Of Refraction ◽  
Density Range ◽  
Temperature Range ◽  
Critical Constants

The index of refraction at 6328 Å has been measured for germane in the density range 0.15 to 0.9 g/cm3. The temperature and density ranges over which measurements are made are near the coexistence curve. The coefficient in the Lorenz–Lorentz expression, [Formula: see text], is constant to within 0.5% within experimental error for the temperature range and density range studied. The coefficient is slightly higher near the critical density. The critical density is measured to be 0.503 g/cm3. The critical temperature is measured to be 38.92 °C.

Density Dependence of Lorentz–Lorenz Coefficient for Sulfur Hexafluoride

1974 ◽  
Vol 52 (20) ◽  
pp. 2007-2010 ◽  
Author(s):  
D. Balzarini ◽  
P. Palffy
Keyword(s):  
High Pressure ◽  
Refractive Index ◽  
Density Dependence ◽  
Sulfur Hexafluoride ◽  
Critical Density ◽  
Small Variation ◽  
Needle Valve ◽  
Density Range ◽  
High Pressure Cell ◽  
Precision Balance

The Lorentz–Lorenz coefficient for sulfur hexafluoride has been measured over the density range 0.1 g/cm3 to 1.3 g/cm3. The critical density has been measured and is 0.736 ± 0.001 g/cm3. Refractive index and density are both measured in the same experiment yielding values of the Lorentz–Lorenz coefficient accurate to 0.05% for densities near critical. The method utilizes a prism-shaped high pressure cell which can be removed from a temperature controlled holder and weighed on a precision balance. The cell is equipped with a needle valve which allows the high pressure gas to be bled out in steps. Refractive index is measured as a function of weight and hence density. Studies of sulfur hexafluoride indicate a small variation of less than 0.5% over the density range covered. A knowledge of the density dependence is necessary for interpretation and verification of the validity of recent experiments near the critical points of pure fluids.

scholarly journals Experimental Studies on Densification and Pressure-Sintering of Ice

1985 ◽  
Vol 6 ◽  
pp. 83-86 ◽  
Author(s):  
Takao Ebinuma ◽  
Norikazu Maeno
Keyword(s):  
Free Surface ◽  
Boundary Diffusion ◽  
Applied Pressure ◽  
Experimental Studies ◽  
Critical Density ◽  
The Other ◽  
Dislocation Creep ◽  
Density Range ◽  
Two Dimensional ◽  
Coordination Numbers

Pressure-sintering experiments of ice particles were carried out at pressures between 0.1 and 2.0 MPa and temperatures between -25 and -9°C. At each experiment, logarithm of the strain rate of densification was proportional to the density, and the slope of proportionality changed at a critical density implying the alternation of predominant densification mechanisms. The critical density varied with applied pressure and temperature, but its variation was restricted between 700 and 750 kg/m3.At densities below the critical density, two-dimensional coordination numbers of constituent particles increased though specific areas of internal free surface were almost constant. The result was explained by the predominant contribution of the process of particle rearrangement in this density range. On the other hand, the contribution of dislocation creep was concluded to be dominant at densities above the critical density; the creep caused by boundary diffusion also contributes especially at higher densities.

scholarly journals Experimental Studies on Densification and Pressure-Sintering of Ice

1985 ◽  
Vol 6 ◽  
pp. 83-86 ◽  
Author(s):  
Takao Ebinuma ◽  
Norikazu Maeno
Keyword(s):  
Free Surface ◽  
Boundary Diffusion ◽  
Applied Pressure ◽  
Experimental Studies ◽  
Critical Density ◽  
The Other ◽  
Dislocation Creep ◽  
Density Range ◽  
Two Dimensional ◽  
Coordination Numbers

Pressure-sintering experiments of ice particles were carried out at pressures between 0.1 and 2.0 MPa and temperatures between -25 and -9°C. At each experiment, logarithm of the strain rate of densification was proportional to the density, and the slope of proportionality changed at a critical density implying the alternation of predominant densification mechanisms. The critical density varied with applied pressure and temperature, but its variation was restricted between 700 and 750 kg/m3. At densities below the critical density, two-dimensional coordination numbers of constituent particles increased though specific areas of internal free surface were almost constant. The result was explained by the predominant contribution of the process of particle rearrangement in this density range. On the other hand, the contribution of dislocation creep was concluded to be dominant at densities above the critical density; the creep caused by boundary diffusion also contributes especially at higher densities.

Interferometric (Fourier-Spectroscopic) Measurement of Electron Energy Distributions

1990 ◽  
Vol 48 (2) ◽  
pp. 110-111 ◽  
Author(s):  
F. Hasselbach ◽  
A. Schäfer
Keyword(s):  
Group Velocity ◽  
Wave Packets ◽  
Index Of Refraction ◽  
Electron Wave ◽  
Fringe Contrast ◽  
Faraday Cage ◽  
Optical Index ◽  
Wien Filter ◽  
Coherent Wave ◽  
Electric And Magnetic Fields

Möllenstedt and Wohland proposed in 1980 two methods for measuring the coherence lengths of electron wave packets interferometrically by observing interference fringe contrast in dependence on the longitudinal shift of the wave packets. In both cases an electron beam is split by an electron optical biprism into two coherent wave packets, and subsequently both packets travel part of their way to the interference plane in regions of different electric potential, either in a Faraday cage (Fig. 1a) or in a Wien filter (crossed electric and magnetic fields, Fig. 1b). In the Faraday cage the phase and group velocity of the upper beam (Fig.1a) is retarded or accelerated according to the cage potential. In the Wien filter the group velocity of both beams varies with its excitation while the phase velocity remains unchanged. The phase of the electron wave is not affected at all in the compensated state of the Wien filter since the electron optical index of refraction in this state equals 1 inside and outside of the Wien filter.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Microspectroscopy Using a Solid Immersion Lens

2001 ◽  
Vol 7 (S2) ◽  
pp. 148-149
Author(s):  
C.D. Poweleit ◽  
J Menéndez
Keyword(s):  
Spatial Resolution ◽  
Focal Plane ◽  
Numerical Aperture ◽  
Normal Incidence ◽  
Spot Size ◽  
Index Of Refraction ◽  
Objective Lens ◽  
Improvement Factor ◽  
Oil Immersion ◽  
Long Time

Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.

Optical properties of a thin layer of the Vanadium dioxide at the metal state

2015 ◽  
Vol 9 (1) ◽  
pp. 2303-2310
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Optical Properties ◽  
Thin Layer ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Cost Of Energy ◽  
Infra Red ◽  
Metal State ◽  
The Cost ◽  
Reversible Phase

The vanadium dioxide VO₂ currently became very motivating for the nanotechnologies’ researchers. It makes party of the intelligent materials because these optical properties abruptly change semiconductor state with metal at a critical  temperature θ = 68°C. This transition from reversible phase is carried out from a monoclinical structure characterizing its semiconductor state at low temperature towards the metal state of this material which becomes tétragonal rutile for  θ ˃ 68°C ; it is done during a few nanoseconds. Several studies were made on this material in a massive state and a thin layer. We will simulate by Maple the constant optics of a thin layer of VO₂ thickness z = 82 nm for the metal state according to the energy ω of the incidental photons in the energy interval: 0.001242 ≤ ω(ev) ≤ 6, from the infra-red (I.R) to the ultra-violet (U.V) so as to be able to control the various technological nano applications, like the detectors I.R or the U.V,  the intelligent windows to  increase  the energy efficiency in the buildings in order to save the cost of energy consumption by electric air-conditioning and the paintings containing nano crystals of this material. The constant optics, which we will simulate, is: the index of refraction, the reflectivity, the transmittivity, the coefficient of extinction, the dielectric functions ԑ₁ real part and  ԑ₂  imaginary part of the permittivity complexes ԑ of this material and the coefficient absorption. 

Optical properties of the Vanadium dioxide

2015 ◽  
Vol 8 (2) ◽  
pp. 2148-2155 ◽  
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Energy Efficiency ◽  
Optical Properties ◽  
Critical Temperature ◽  
Thin Layer ◽  
Dielectric Function ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Practical Utility ◽  
Infra Red

The vanadium dioxide is a material thermo chromium which sees its optical properties changing at the time of the transition from the phase of semiconductor state ↔ metal, at a critical temperature of 68°C. The study of the optical properties of a thin layer of VO₂ thickness 82 nm, such as the dielectric function, the index of refraction, the coefficient ofextinction, the absorption’s coefficient, the reflectivity, the transmittivity, in the photonic spectrum of energy ω located inthe interval: 0.001242 ≤ ω (ev) ≤ 6, enables us to control well its practical utility in various applications, like the intelligentpanes, the photovoltaic, paintings for increasing energy efficiency in buildings, detectors of infra-red (I.R) or ultra-violet(U.V). We will make simulations with Maple and compare our results with those of the literature

Sign in / Sign up

Export Citation Format

Share Document