Determination of the coefficient of volume expansion for liquids

We present a theoretical method for an approximate determination of the coefficient of volume expansion for liquids at the saturation line. The theory of similarity and the molecular characteristics of the materials serve as the basis for the derivation of quantitative relationships.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 6, pp. 1034–1038, June, 1969.     

Small-angle light scattering spectra of disperse particles suspended in absorbing liquids

The spectra of small-angle light scattering (SALS) by disperse particles suspended in an absorbing liquid have been numerically simulated using the Mie theory and measured in a wavelength range from 190 to 1100 nm. It is established that the SALS spectra contain regions sensitive to the size and polydispersity of particles with radii ranging from 0.4 to 30 μm. Using the joint processing of SALS and transmission spectra measured using a double-beam spectrophotometer with a modified optical scheme, it is possible to determine the parameters of particles suspended in the absorbing liquid. Data for model suspensions of polystyrene latex particles are presented.     

Determination of the momentum distribution of scattering particles from high-Q scattering spectra of a resonance detector neutron spectrometer

We have measured high-Q neutron scattering spectra from various crystaline solids using an eV resonance detector spectrometer, and analyzed the different contributions to the line profile, namely the finite time spread of the neutron pulse, the detector resolution, the finite size of the moderator, sample and detector, the scattering function and multiple scattering processes, by first-principle calculations. The calculated spectra agree well with the experiments. The momentum distribution of scattering particles can be determined from the high-Q limit of the scattering function. However, deviations from this asymptotical form are clearly observed even for momentum transfers around 100 Å⁻¹.     

Determination of size, refractive index, and dispersion of single droplets from wavelength-dependent scattering spectra

Intensities of light scattered in the planes parallel and perpendicular to the polarization plane of the incident light are used to determine the size, refractive index, and dispersion of a single droplet suspended in an electrodynamic balance. Wavelengths of TE- and TM-mode resonances are determined independently with high precision when a ring dye laser is scanned. Resonating wavelengths are matched with theoretical intensity peaks to determine the constants of a dispersion formula and the size that minimizes the difference between observed and calculated wavelengths. The procedure permits the determination of the size and refractive index with relative errors of 3 × 10(-5) and dispersion with an absolute error 2 × 10(-5) over the experimental spectral range.     

Thermodynamics of strong coupling superconductors including the effect of anisotropy

The thermodynamics of several elemental superconductors is computed from isotropic Eliashberg theory formulated on the imaginary frequency axis. A symmary of the available experimental literature is presented and a comparison with theory is given. The small disagreements that are found are all in the direction expected from anisotropy effects. We calculate the effect of a small amount of model anisotropy on the critical temperature, critical field, and high-temperature specific heat from an exact solution of the anisotropic Eliashberg equations. These are the first such results below the critical temperature; unlike previous analytical work, we include retardation, anisotropy in the mass enhancement, and the effect of the Coulomb repulsion in enhancing anisotropy, all of which are significant. We derive a new formula independent of any model anisotropy for the rate of decrease with impurity lifetime of the critical temperature. Finally we demonstrate how the commonly used formulas of Markowitz and Kadanoff and of Clem may give entirely misleading estimates of the gap anisotropy when used to interpret certain experiments.Research supported by the Natural Sciences and Engineering Research Council of Canada.     

The molecular roughness factor from the bulk viscosity coefficient

The translational-rotational coupling factor, or roughness factor, introduced by Chandler, has been evaluated for two types of nonpolar liquids along the saturation line. For the first type (atomic liquids), a universal correlation has been found. For the second type (alkanes), this quantity presents a sharp increase in the neighborhood of the solid-fluid transition for hard spheres. This parameter plays an essential role, since it allows a link to be established between simulation and experimental data.     

Effects of heat-transfer anisotropy in convective streams of liquids and gases

A study is made concerning the anisotropy of thermal conductivity in a medium in a state of strain and concerning the effect of this anisotropy on the heat-transfer characteristics during forced convection.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 25, No. 4, pp. 720–724, October, 1973.     

Viscosity measurement of Newtonian liquids using the complex reflection coefficient

This work presents the implementation of the ultrasonic shear reflectance method for viscosity measurement of Newtonian liquids using wave mode conversion from longitudinal to shear waves and vice versa. The method is based on the measurement of the complex reflection coefficient (magnitude and phase) at a solid-liquid interface. The implemented measurement cell is composed of an ultrasonic transducer, a water buffer, an aluminum prism, a PMMA buffer rod, and a sample chamber. Viscosity measurements were made in the range from 1 to 3.5 MHz for olive oil and for automotive oils (SAE 40, 90, and 250) at 15 and 22.5degC, respectively. Moreover, olive oil and corn oil measurements were conducted in the range from 15 to 30degC at 3.5 and 2.25 MHz, respectively. The ultrasonic measurements, in the case of the less viscous liquids, agree with the results provided by a rotational viscometer, showing Newtonian behavior. In the case of the more viscous liquids, a significant difference was obtained, showing a clear non-Newtonian behavior that cannot be described by the Kelvin-Voigt model.     

Determination of fractional concentrations and exact component spectra by factor analysis of pyrolysis mass spectra of mixtures

Windig, W., McClennen, W.H. and Meuzelaar, H.L.C., 1987. Determination of fractional concentrations and exact component spectra by factor analysis of pyrolysis mass spectra of mixtures. Chemometrics and Intelligent Laboratory Systems, 1: 151–165.Factor analysis of the “correlation around the origin” matrix as applied to (pyrolysis—) mass spectrometry data is described. This approach makes it possible to calculate the spectra of pure components from a data set of mixtures in which these pure components are not present. Further, the fractional concentrations of the components in the mixtures can be calculated. Examples are given of results obtained on data sets consisting of (pyrolysis) mass spectra from biopolymers, jet fuels and technical polymers.     

Definition of the diffusion coefficient in scattering and absorbing media

We revisit the definition of the diffusion coefficient for light transport in scattering and absorbing media. From an asymptotic analysis of the transport equation, we present a novel derivation of the diffusion coefficient, which is restricted neither to low absorption nor to a situation in which the specific intensity is quasi-isotropic. Our result agrees with previous expressions of the diffusion coefficient in the appropriate limit. Using numerical simulations, we discuss the implications of the proper choice of the diffusion coefficient for time-dependent transport.     

Influence of scattering anisotropy on the emission of two-phase media

An approximate solution of the transfer equation in a plane medium with anisotropic scattering is compared with the exact solution. It is shown that the approximate solution agrees well with the exact solution.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 5, pp. 894–896, May, 1978.     

激光光散射法测定聚乳酸分子量及其分子量分布

介绍了一种用于测定聚乳酸分子量及其分布的多角度激光光散射法；给出了该方法的实验步骤及结果。该法以四氢呋喃为溶剂和流动相，凝胶渗透色谱柱为分离体系，结合十八角激光散射仪和示差折光仪等检测器进行联机测量。实验测得合成聚乳酸重均分子量在30000-150000g／mol之间，分子量分布（Mw／Mn）为1.3～1．8。     

Plano-concave microcuvette for measuring the absorption coefficient of highly absorbing liquids

A powerful and simple method based on the use of a plano-concave microcuvette was investigated for measuring the absorption coefficient of highly absorbing liquids. A plano-convex lens put on a plane-parallel plate formed a microcuvette with small, continuously varying thicknesses. This microcuvette was filled with liquid and illuminated by a homogeneous beam. The parabolic variation of the liquid thickness generates a Gaussian spatial intensity distribution behind the cuvette. This Gaussian profile, detected by a CCD camera, was used to determine the absorption coefficient of the liquid. An absorption coefficient as high as 1.54 x 10(4) cm(-1) was measured by use of high-concentration malachite green dye solutions. A comparison of the results with data extrapolated from those of conventional methods showed good agreement.     

Measurements of the Doppler spectra of breaking waves

A number of experiments have been carried out in two large wave tanks with three different radar systems. The radar frequency, grazing angle, azimuth angle, water wavelength, wave steepness and the breaking wave strength were all varied systematically. The velocity of the peak Doppler power spectral density was found to depend on the phase velocity of the breaking wave in the radar line of sight, but was independent of the radar frequency. The spectral width depended on the phase velocity of the wave, but not on the grazing angle used. The peak Doppler power and radar cross-section of the breaking waves was found to scale with the radar wavelength (proplambda_r ^1.5)