Conductivity and noise problem of plasma antennas
Investigation the plasma antenna on the basis of UHF discharge near the second Langmuir resonance (subresonance) is continuing. Measurements are given on the admission of signals. It is provied reducing the thermal and fluctuation noise of UHF discharge compared with metal.
Plasma antennas based on UHF discharge
Studied are the antenna properties of the UHF discharge plasma at the threshold of the resonance of the electron Langmuir frequency with the pump second harmonic. The results of experimental measurements of some characteristics of a plasma antenna-amplifier at the LF range are shown. A mathematical model of a similar antenna, which allows proceeding to a physical model of the distributed parametric amplifier, is built.
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.