Interferometric studies in diffusion. I. Determination of concentration distributions

1950 ◽  
Vol 204 (1078) ◽  
pp. 339-359 ◽  
Keyword(s):  
Refractive Index ◽  
Abrupt Change ◽  
Sudden Change ◽  
Small Range ◽  
Component Systems ◽  
Different Temperatures ◽  
Two Component Systems ◽  
Index Curve ◽  
And Diffusion

An interferometer technique for the quantitative study of swelling and diffusion in transparent high polymers and a method of determining the concentration distribution from the fringe system have been developed. The concentration—distance curves in the system chloroform-stretched cellulose acetate have been determined at two different temperatures with a view to estimating activation energies over a range of concentrations. The curves are found to consist of two almost linear portions with a considerable and abrupt change of gradient taking place over a small range of concentration. A corresponding sudden change of gradient has been observed in other systems. Considerable experimental difficulties were met in determining the refractive index and density curves for the two component systems, which were required by the method. Eventually a refractive index curve was constructed with the help of data obtained by several approaches.

The influence of oxygen pressure on lead oxidation kinetics

1980 ◽  
Vol 33 (3) ◽  
pp. 471 ◽  
Author(s):  
GA Hope
Keyword(s):  
Refractive Index ◽  
Pressure Dependence ◽  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Abrupt Change ◽  
Oxide Interface ◽  
Positive Dependence ◽  
Different Temperatures ◽  
Lead Films ◽  
Lead Oxidation

The dependence of the oxidation rate of lead films on the pressure of oxygen was investigated by ellipsometric and resistance techniques for oxygen pressures between 200 Pa and 100 kPa and in the temperature range 323-423 K. Measurements of the pressure dependence were obtained by studying the change in oxidation rate following an abrupt change in pressure. The results of all experiments indicated a small positive dependence, though significant variations in the values were observed both with extent of oxidation, and between experiments conducted at different temperatures. During the first few minutes of the reaction an unusual trend was noted in the observed kinetics which could be interpreted as being due to absorption of oxygen, by the metal close to the metal-oxide interface, resulting in changes to the metal conductivity and the refractive index, determined by ellipsometry, of the lead substrate.

THE CRITICAL TEMPERATURES AND PRESSURES OF THE THREE TWO-COMPONENT SYSTEMS COMPRISED OF CARBON DIOXIDE, METHYL ETHER AND PROPYLENE

1932 ◽  
Vol 6 (5) ◽  
pp. 458-470 ◽  
Author(s):  
C. A. Winkler ◽  
O. Maass
Keyword(s):  
Carbon Dioxide ◽  
Methyl Ether ◽  
Critical Temperatures ◽  
Compound Formation ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
First Time ◽  
Three Components

The so-called critical temperatures and critical pressures for two-component systems are defined. For the first time three two-component systems have been investigated, involving three components taken two at a time. The three components were propylene, methyl ether and carbon dioxide. An experimental technique involving several new features is described. Accuracy in the determination of both critical temperatures and pressures is claimed. The system sulphur dioxide-methyl ether was also examined and the conclusions of previous investigators regarding compound formation confirmed. The results of the other three systems are analyzed and a theoretical discussion of these results reserved for a later publication.

Determination of 2V from one extinction curve and its related n0 curve

1963 ◽  
Vol 33 (263) ◽  
pp. 679-692 ◽  
Author(s):  
N. Joel
Keyword(s):  
Refractive Index ◽  
Extinction Curve ◽  
Biaxial Crystal ◽  
Principal Axes ◽  
Index Curve ◽  
Constant Refractive Index

SummaryFrom the extinction curve of a biaxial crystal mounted on a spindle stage (or one-axis stage goniometer), the related n0 curve can be derived and drawn on the stereogram. The n0 curve is the equivibration curve—or constant-refractive-index curve—that goes through the projection P0 of the spindle-stage axis. After the principal diameters (maximum 2η and minimum 2ζ) of the no curve have been measured, the angle 2V may be calculated by means of the formula cos V = sin ζ/sin η. This method can also be used for determining—or refining—the directions of the principal axes α, β, γ.

scholarly journals Measurement of Wavelength and Temperature-Dependent Optical Properties of Thermochromic Pigments

2017 ◽  
Vol 72 (2) ◽  
pp. 297-304 ◽  
Author(s):  
Jianying Hu ◽  
Xiong (Bill) Yu
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Transition Temperature ◽  
Optical Constants ◽  
Temperature Dependent ◽  
Thermochromic Material ◽  
Different Temperatures ◽  
Cubic Polynomial ◽  
Thermochromic Pigment

Thermochromic material is a substance that is capable of changing reversibly the color as the temperature rises. Therefore, the optical spectrum of thermochromic material is responsive to the environmental temperature. In this study, the temperature-dependent optical constants of thermochromic pigments over the wavelength of 350–1800 nm were investigated. Three kinds of thermochromic pigments featured with black, blue, and red colors at room temperature were suspended in water and the light reflection and transmission of the suspensions at different temperatures were measured by a multifunctional spectrophotometer. It was found that below the transition temperature of thermochromic material, the refractive index was 2.1–2.5, 2.2–2.6, and 2.0–2.4 over the wavelength range of 350–1800 nm for black, blue, and red thermochromic pigment, respectively, while above the transition temperature it reached 2.3–2.7, 2.4–2.9, and 2.4–2.7, respectively. It was also observed that the relationship between refractive index of thermochromic pigment and wavelength follows the cubic polynomial function. Furthermore, the extinction coefficient is in the range of 1 × 10−5–1.2 × 10−4 for all thermochromic pigments and remains approximately stable at different temperatures. The determination of optical constants of thermochromic pigments provides essential parameters in the modeling of light scattering and absorption by pigment particles to further fine-tune the optical properties of thermochromic coating.

The Determination of Concentrations in the Ultracentrifugation of Two‐Component Systems

1954 ◽  
Vol 22 (3) ◽  
pp. 555-559 ◽  
Author(s):  
R. Trautman ◽  
V. N. Schumaker ◽  
W. F. Harrington ◽  
H. K. Schachman
Keyword(s):  
Component Systems ◽  
Two Component ◽  
Two Component Systems

Development of Experimental Set for Determination of Refractive Index of Liquid Using Optical Fiber

2016 ◽  
Vol 675-676 ◽  
pp. 722-725
Author(s):  
Tewarit Khanmolee ◽  
Kheamrutai Thamaphat ◽  
Pichet Limsuwan
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Water Temperature ◽  
Fiber Optics ◽  
Output Voltage ◽  
Fiber Optic ◽  
School Class ◽  
High School Class ◽  
Different Temperatures

The construction of an experimental set for measurement of refractive index of liquids using fiber optics has been described in this work. The experimental set is aimed for demonstration in physics high school class. A prototype fabricated in laboratory composes of plastic-clad-plastic (PCP) optical fiber with the length of 50 cm, fiber optic transmitter diode, fiber optic phototransistor detector, and liquid container. The diameter and refractive index of the core of PCP optical fiber were 1 mm and 1.492, respectively. The thickness and refractive index of fiber cladding were 1.2 mm and 1.417, respectively. The fiber cladding surface at the central region was removed approximately 5 cm long to form a sensor area. This sensor area was inserted into a cylindrical glass which acted as the container. One end of the fiber was connected to the transmitter diode with a wavelength of 660 nm, and the other end was connected to the detector. A digital multimeter was used to measure an output voltage from the detector. In this work, the effect of water temperature on its refractive index was determined. The results showed that the water refractive index decreased with increasing water temperature and result in the increase of measured output voltage. Furthermore, it was found that the output voltage measured at different temperatures of water depends linearly on water refractive index.

The refractive index dispersion and polarization of gases

1936 ◽  
Vol 156 (887) ◽  
pp. 144-157 ◽  
Keyword(s):  
Refractive Index ◽  
Dipole Moments ◽  
Refractive Index Dispersion ◽  
Electronic Polarization ◽  
Empirical Basis ◽  
Infra Red ◽  
Different Temperatures ◽  
Dielectric Coefficient ◽  
Zero Frequency

In recent years, values of the refractive index of liquids, and sometimes of gases, have been extensively used for determining dipole-moments. Measurements of dielectric coefficients give the sum of the orientation, electronic and atomic polarizations P 0 + P e +P a , while the electronic polarization P e can be calculated approximately from the refractive index. If the dispersion is known, P e should be given with some accuracy by calculating the refractive index at zero frequency. In order to obtain P 0 , it is necessary to know P a , a quantity which has only been determined for a few substances, the infra-red spectrum of which has been examined in detail. It is, however, often assumed that P a is negligible or, at least, small in comparison with P e . In some cases, an approximation on an empirical basis has been made by assuming that P a is proportional to P e , or that P a + P e is equal to the value of P e when calculated from the refractive index for the yellow sodium line. Such assumptions can hardly be regarded as satisfactory. In liquids, determination of the polarization is complicated by the necessity of employing a solvent, but, with gases, no such difficulty exists. P a can therefore be determined with some accuracy by measuring the refraction for different wave-lengths, and the dielectric coefficient at different temperatures. Numerous measurements of the refractive index of the commoner gases have been made, but the results of different observers are not always in agreement and frequently the dispersion has not been determined. The dielectric coefficient of the same sample of gas seems never to have been measured.

Quantitative Assessment of Soluble Fibrin in Plasma by Affinity Chromatography – A Comparative Study with desAA-Fibrin, desAABB-Fibrin and Fibrinogen

1985 ◽  
Vol 54 (02) ◽  
pp. 533-538 ◽  
Author(s):  
Wilfried Thiel ◽  
Ulrich Delvos ◽  
Gert Müller-Berghaus
Keyword(s):  
Affinity Chromatography ◽  
Calcium Ions ◽  
Quantitative Assessment ◽  
Fluid Phase ◽  
Soluble Fibrin ◽  
Binding Characteristics ◽  
Different Temperatures ◽  
Immobilized Proteins ◽  
Sepharose 4B

SummaryA quantitative determination of soluble fibrin in plasma was carried out by affinity chromatography. For this purpose, desAA-fibrin and fibrinogen immobilized on Sepharose 4B were used at the stationary side whereas batroxobin-induced 125I-desAA-fibrin or thrombin-induced 125I-desAABB-fibrin mixed with plasma containing 131I-fibrinogen represented the fluid phase. The binding characteristics of these mixtures to the immobilized proteins were compared at 20° C and 37° C. Complete binding of both types of fibrin to the immobilized desAA-fibrin was always seen at 20° C as well as at 37° C. However, binding of soluble fibrin was accompanied by substantial binding of fibrinogen that was more pronounced at 20° C. Striking differences depending on the temperature at which the affinity chromatography was carried out, were documented for the fibrinogen-fibrin interaction. At 20° C more than 90% of the applied desAA-fibrin was bound to the immobilized fibrinogen whereas at 37° C only a mean of 17% were retained at the fibrinogen-Sepharose column. An opposite finding with regard to the tested temperature was made with the desAABB-fibrin. Nearly complete binding to insolubilized fibrinogen was found at 37° C (95%) but only 58% of the desAABB-fibrin were bound at 20° C. The binding patterns did not change when the experiments were performed in the presence of calcium ions. The opposite behaviour of the two types of soluble fibrin to immobilized fibrinogen at the different temperatures, together with the substantial binding of fibrinogen in the presence of soluble fibrin to insolubilized fibrin in every setting tested, devaluates affinity chromatography as a tool in the quantitative assessment of soluble fibrin in patients’ plasma.

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