SEARCHING FOR RESERVE FOR EXPANSION OF THE POSSIBILITIES TWO-ENERGY RADIOGRAPHY
Theoretical analysis and experimental studies show that the two-energy detection method not only allows one to detect organics on the background of metal, but also substantially increases (by 3-5 times) the detection ability of the system as a whole, especially if parameters of the S-PD pair are optimized, in particular, when ZnSe(Te) is used in the low-energy circuit. A possibility to distinguish, in principle, between substances with insignificant differences in atomic number has been theoretically proven – by transition to multi-energy radiography. 3Dimaging has been realized using S-PD detector arrays. Results of experimental studies of detector arrays S-PD used for X-ray digital radiography have shown that there exist further possibilities to increase spatial resolution of this system up to 2-3 line pairs per mm.
Determining chemical compositions by the method of multi-energy radiography
A theoretical model of multi-energy radiography is proposed and two approaches—“synthesis” and “analysis”—to studying the structure of objects by this method are considered. It is theoretically proved that the atomic numbers of elements and the other parameters of chemical composition of a sample can be restored from the multichannel absorption data. The multi-energy radiography approach and possible generalizations open wide prospects for both basic experimental investigations and nondestructive testing applications.
Cognitive Correlaretes of Physics Achievement of Some Nigeria Senior Secondary Students
Some cognitive correlates of physics achievement of some Nigeria senior secondary students were considered in the study. Specifically, the study examined the relationship between measures of student’s field independency. Cognitive tasks, formal reasoning and their achievement in physics. Purposive and stratified random sampling techniques were employed to obtain a sample of 524 senior secondary two students from six education zones in Kogi State of Nigeria. Three instruments were used. They are science Reasoning Tasks (SRTs). Group Embedded Figures Test (GEFT) and Physics Achievement Test (PAT). Data analysis using multiple regressions reveals that measures of students’ fields’ independency and cognitive tasks predicted student’s achievement in physics generally. However, only measure of field independency predicted students’ achievement in physics in the higher order cognitive demand questions. Measures of formal reasoning had no significant relationship with students’ achievements in physics generally or in higher order cognitive demand questions in physics. However, the overall relationships between measures of field independency, cognitive tasks, formal reasoning and students’ achievement in physics generally and in higher order cognitive demand questions in physics were both significant. Educational implications of these findings were discussed.