scholarly journals A GRAPHIC DETERMINATION OF THE DRIFT CONSTANTS IN DEBYE SCHERRER PHOTOGRAPHS AND THE ACCURATE EVALUATION OF LATTICE CONSTANTS

1980 ◽  
Vol 29 (3) ◽  
pp. 273
Author(s):  
LU XUE-SHAN
Keyword(s):  
Accurate Evaluation ◽  
Lattice Constants ◽  
Graphic Determination

A neutron powder diffraction determination of the thermal expansion tensor of crocoite (PbCrO4) between 60 K and 290 K

1996 ◽  
Vol 60 (403) ◽  
pp. 963-972 ◽  
Author(s):  
Kevin S. Knight
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Powder Diffraction ◽  
Maximum Expansion ◽  
Lattice Constants ◽  
Thermal Expansion Tensor ◽  
Diffraction Determination ◽  
Line Passing ◽  
Neutron Time

AbstractThe thermal expansion tensor of crocoite has been determined from high-resolution neutron time-of-flight powder diffraction data. The temperature dependence of the lattice constants between 4.5 K and 290 K have been fitted to a quasi-harmonic Einstein model, and the temperature dependence of the thermal expansion tensor has been calculated for 60 K ≤ T ≤ 290 K. The magnitudes of the principal expansivities and their orientation exhibit saturation behaviour for temperatures above 300 K. The predicted saturated expansion coefficients are α11 = 33.1(1) × 10−6K−1, α22 = 15.72(3) × 10−6K−1, α33 = 3.36(1) × 10−6K−1, with α22 parallel to b and α11 lying at an angle of −37.86(5)° to c for the P21/n setting of the crystal structure. The direction of maximum expansion is approximately parallel to both and the least-squares line passing through the projection of the chromium atoms on (010). The direction of minimum expansion lies approximately parallel to [101]. No evidence was found for either a structural or magnetic phase transition between 4.5 K and 300 K.

scholarly journals RESEARCH INTO THE METHODS OF ANALYSING THE PRODUCTIVITY INDICATORS OF TRANSPORT TERMINALS

Transport ◽  
2009 ◽  
Vol 24 (3) ◽  
pp. 192-199 ◽  
Author(s):  
Ilona Jaržemskienė
Keyword(s):  
Comparative Analysis ◽  
Functional Dependence ◽  
Data Envelopment ◽  
Analysis Method ◽  
Accurate Evaluation ◽  
Feasible Alternative ◽  
Productivity Indicators ◽  
Insight Into ◽  
Regressive Analysis

The measurement of terminal productivity is the issue of extreme importance to both terminal owners and management and customers. As the sector of transport is highly intensive in terms of investments into the infrastructure, the productivity of a terminal may play a crucial role in competing with other terminals. Productivity is defined in terms of inputs and output. The majority of the available studies, wherein this issue is addressed, are generally focused on the determination of functional dependence between inputs and output using the method of regressive analysis. The present article provides an insight into the Data Envelopment Analysis method as a tool for measuring productivity. This technique enables a rather accurate evaluation of terminal productivity by means of comparative analysis, which, in fact, appears to be the only feasible alternative in cases where statistic data required for performing regressive analysis is lacking.

YLiSn — eine ternäre Verbindung mit verzerrtem Li-Sn-Wurtzitgerüst / YLiSn - a Ternary Compound with Distorted Li - Sn - Wurtzit - Type Lattice

1979 ◽  
Vol 34 (8) ◽  
pp. 1165-1166 ◽  
Author(s):  
Gunter Steinberg ◽  
Hans-Uwe Schuster
Keyword(s):  
Ternary Compound ◽  
Structure Determination ◽  
Space Group ◽  
X Ray ◽  
Lattice Constants ◽  
Type Lattice

The X-ray structure determination of YLiSn showed that Li and Sn form a weakly distorted Wurtzit-type lattice, whose octahedral lacunas are occupied by Y. The lattice constants of the hoxagonally crystallizing compound are a = 929.6 pm and c = 734.6 pm, space group P 63mc, Z = 8

Pseudopotential Calculations of Structural Properties of Solids

1985 ◽  
Vol 63 ◽  
Author(s):  
Marvin L. Cohen
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Vibrational Properties ◽  
Structural Phase Transitions ◽  
Superconducting Properties ◽  
Lattice Constants ◽  
Pseudopotential Calculations ◽  
Pseudopotential Approach ◽  
Cohesive Energies

ABSTRACTThrough the development of a total energy pseudopotential approach, it has become possible to compute structural, electronic, and vibrational properties of solids using only the atomic numbers and atomic masses of the constituent atoms as input. The method has been applied to semiconductors, insulators, and metals; and agreement with experiment for most properties is usually within a few percent.Applications include the determination of lattice constants for specific structural phases, properties of structural phase transitions, cohesive energies, bulk moduli, lattice vibrational spectra, electron-lattice interaction parameters, and electronic and superconducting properties. A recent example is the prediction of superconductivity in highly condensed hexagonal silicon which was subsequently found experimentally.

The change in the pH of the semen of the bull after incubation

1944 ◽  
Vol 34 (2) ◽  
pp. 69-72 ◽  
Author(s):  
James Anderson
Keyword(s):  
Accurate Evaluation ◽  
Clinically Normal ◽  
The Mean ◽  
Phosphate Medium

The mean change in the pH of 134 undiluted ejaculates of clinically normal bulls was –0·302 ± 0·027 after 1 hr. storage at 37°C. The greater the pH. change, the lower was the initial pH and the higher was the initial motility and the number of spermatozoa per c.mm. The greater the decrease in pH the poorer was the motility after incubation. The motility was better maintained in semen diluted with egg-phosphate medium, compared with undiluted semen, which agreed with the smaller pH change in this medium. There was no evidence of a relationship between the pH change and the motility after incubation and the period of time for which a high motility was maintained during storage. It is suggested that the determination of the initial pH and the pH change after 1 hr. incubation may provide a useful and accurate evaluation of the semen of the bull.

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