Solar Radiations in the 4–6 Metre Radio Wave-Length Band

1946 ◽  
pp. 166-167
Author(s):  
J. S. Hey
Keyword(s):  
Radio Wave ◽  
Wave Length

VARIATION OF METEOR ECHO RATES WITH RADAR SYSTEM PARAMETERS

1951 ◽  
Vol 29 (5) ◽  
pp. 403-426 ◽  
Author(s):  
D. W. R. McKinley
Keyword(s):  
Radio Wave ◽  
Wave Length ◽  
Radar System ◽  
Antenna Gain ◽  
Scattering Pattern ◽  
Magnitude Distribution ◽  
System Parameters ◽  
Transmitter Power ◽  
Meteor Trail ◽  
Strong Filter

Observations made with crossed-polarization radar system systems do not support the suggestion that the ionized meteor trail may act as a strong filter–polarizer of the incident radio wave. Experiments have been carried out to determine the variation of normal meteor echo rates with transmitter power, antenna gain, and radio wave length, and all confirm Lovell's scattering formula, provided that account is taken of the effective broadening of the scattering pattern of the meteor trail with increasing wave length. The limiting sensitivity of the 9.22 m. 200 kw. radar is determined to be about 9th magnitude. During a strong visual shower the observed increase in visual rates and low-power radar rates, compared to high-power radar rates, is explained by assuming that the magnitude distribution of the shower meteors differs from the normal nonshower distribution.

METEOR ECHO DURATION AND RADIO WAVE LENGTH

1953 ◽  
Vol 31 (7) ◽  
pp. 1121-1135 ◽  
Author(s):  
D. W. R. McKinley
Keyword(s):  
Radio Wave ◽  
Short Duration ◽  
Wave Length ◽  
The Other ◽  
Radar Echoes ◽  
Radio Equipment ◽  
Straight Lines

The durations of radar echoes from meteors have been observed simultaneously on 9.22 m. and 5.35 m., and also on 9.22 m. and 2.83 m. The ratio of durations on two wave lengths decreases with increasing duration by a factor of two over the observed range, deviating significantly from the accepted square law of wave length. Plotting the log of the ratio against the log of the duration yields two straight lines of different slopes, one in the short-duration range and the other applying to the longer echoes. General empirical formulae are developed to predict the echo duration on one radio equipment in terms of the duration of the same echo recorded by another apparatus of different sensitivity and wave length.

Solar Radiations in the 4–6 Metre Radio Wave-Length Band

Nature ◽  
1946 ◽  
Vol 157 (3976) ◽  
pp. 47-48 ◽  
Author(s):  
J. S. HEY
Keyword(s):  
Radio Wave ◽  
Wave Length

Solar Radiations in the 4–6 Metre Radio Wave-Length Band

Nature ◽  
1946 ◽  
Vol 157 (3976) ◽  
pp. 48-48 ◽  
Author(s):  
F. J. M. STRATTON
Keyword(s):  
Radio Wave ◽  
Wave Length

scholarly journals The optical and electrical non-invasive methods of measurement for glucose concentration in biological liquids

2021 ◽  
Vol 2140 (1) ◽  
pp. 012039
Author(s):  
Y K Zhexenbayev ◽  
T D Bulembayev ◽  
A V Gorst ◽  
K V Zavyalova ◽  
A S Mironchev ◽  
...  
Keyword(s):  
Radio Wave ◽  
Glucose Concentration ◽  
Optical Method ◽  
Near Field ◽  
Wave Length ◽  
Optical Methods ◽  
Field Zone ◽  
Bidistilled Water ◽  
Body Tissues ◽  
Field Sensor

Abstract The article describes the radio-wave and optical methods of determining glucose concentration. The radio-wave method is based on the use of a sensor with a resonant frequency that is displayed when in contact with highly lossy materials and with an extended near-field zone in the resonance area. The optical method is based on studying the influence of glucose concentration (0–20 mmol/l) in bidistilled water on absorption spectra in the range of 190-1000 nm. The article presents the results of the experimental test of the near-field sensor with the pre-produced biological media imitating the human body tissues, and the results of the optical method demonstrate the possibility to measure the concentration with the use of an optical emitter with a wave length of 830 nm.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes

1990 ◽  
Vol 48 (1) ◽  
pp. 202-203
Author(s):  
H. Rose
Keyword(s):  
Spherical Aberration ◽  
Wave Length ◽  
Electron Wave ◽  
Optical Lens ◽  
Resolution Electron ◽  
Rotationally Symmetric ◽  
Electron Microscopes ◽  
The Cost ◽  
Imaging Performance ◽  
Acceleration Voltage

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

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