Temperature dependence of pressure broadening of the N = 1− fine structure oxygen line at 118.75 GHz

The absorption profile of the N = 1− fine structure line of oxygen was recorded by a resonator spectrometer at a frequency range of 110-130 GHz at atmospheric pressure and different temperatures ranging from −21 °C up to +22 °C. Analysis of the observed line shape allowed determination of the temperature dependence of the line pressure broadening. The measured value of the temperature exponent is n = 0.74(5) for self-broadening. Consistency of the measurements is supported by simultaneous measurements of the line intensity, the line mixing parameter and the line center frequency, and by comparison of obtained values with previously known data.     

Radio reception

The last few decades saw considerable progress in the methods of reception of radio signals, in particular, in the short-wave part of millimeter wave range. Along with this, or, perhaps, owing to this, some views, concepts, and definitions in the theory of detection and mixing were changed. Consequently, for example, the concepts and the corresponding apparatus developed in the 1950s need at present certain corrections. Below we propose a nonstandard consideration of the detection and mixing processes on the basis of consistent observance of the principle of information theory on the energy character of signal reception and using the time-domain approach when describing the operation of superheterodyne converters. To my teacher in practical radiophysics, professor Izrail’ Lazarevich Bershtein with gratitude. Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 11, pp. 1378–1398, November, 1998.     

Clear-air millimeter-wave scattering

Clear-air millimeter-wave backscattering is observed experimentally by means of a high-power gyrotron generator and a superheterodyne receiver.Institute of Applied Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 10, pp. 942–944, October, 1993.     

Seismoacoustic emission of an oil-producing bed

Results are presented from a study of seismoacoustic emission appearing in an oil-saturated porous geological medium under the acoustic force action in a borehole. It is shown that dynamic nonlinear processes in the producing bed are activated under the internal elastic action on the stratum, changing the energy state of the medium, and this change can be seen as a change in the acoustic emission pattern. The correlation between the high-frequency part of the acoustic emission spectrum and the low-frequency one is found, indicating the development of this process in space at different scale levels.     

Acoustic effects in the deformation of structually inhomogeneous media

The paper demonstrates that during triaxial loading of a core sample of dry sandstone, genetically related frequency ranges form in the waveguide, which are significantly spatially separated, but have a similar dynamics. This is explained by the authors' previously suggested model for the generation of a low-frequency branch of seismic emission as a result of amplitude instability of the seismic envelopes of acoustic oscillations in a structurally inhomogeneous medium.     

Intercomparison of radiation measurements on STS-63

A joint NASA Russia study of the radiation environment inside the Space Shuttle was performed on STS-63. This was the second flight under the Shuttle-Mir Science Program (Phase 1). The Shuttle was launched on 2 February 1995, in a 51.65° inclination orbit and landed at Kennedy Space Center on 11 February 1995, for a total flight duration of 8.27 days. The Shuttle carried a complement of both passive and active detectors distributed throughout the Shuttle volume. The crew exposure varied from 1962 to 2790 μGy with an average of 2265.8 μGy or 273.98 μGy/day. Crew exposures varied by a factor of 1.4, which is higher than usual for STS mission. The flight altitude varied from 314 to 395 km and provided a unique opportunity to obtain dose variation with altitude. Measurements of the average east-west dose variation were made using two active solid state detectors. The dose rate in the Spacehab locker, measured using a tissue equivalent proportional counter (TEPC), was 413.3 μGy/day, consistent with measurements made using thermoluminescent detectors (TLDs) in the same locker. The average quality factor was 2.33, and although it was higher than model calculations, it was consistent with values derived from high temperature peaks in TLDs. The dose rate due to galactic cosmic radiation was 110.6 μGy/day and agreed with model calculations. The dose rate from trapped particles was 302.7 μGy/day, nearly a factor of 2 lower than the prediction of the AP8 model. The neutrons in the intermediate energy range of 1–20 MeV contributed 13 μGy/day and 156 μSv/day, respectively. Analysis of data from the charged particle spectrometer has not yet been completed.     

System for measuring collective scattering spectra for thermonuclear plasma diagnostics

The design and arrangement of a detection system for measuring spectra, using a 140 GHz gyrotron as the probe-radiation source, developed for investigating collective Thomson scattering in plasma are discussed. The measurement procedure and examples of the results obtained are presented. Zh. Tekh. Fiz. 68, 54–62 (August 1998)     

In-flight radiation measurements on STS-60

A joint investigation between the United States and Russia to study the radiation environment inside the Space Shuttle flight STS-60 was carried out as part of the Shuttle-Mir Science Program (Phase 1). This is the first direct comparison of a number of different dosimetric measurement techniques between the two countries. STS-60 was launched on 3 February 1994 in a nearly circular 57 degrees x 353 km orbit with five U.S. astronauts and one Russian cosmonaut for 8.3 days. A variety of instruments provided crew radiation exposure, absorbed doses at fixed locations, neutron fluence and dose equivalent, linear energy transfer (LET) spectra of trapped and galactic cosmic radiation, and energy spectra and angular distribution of trapped protons. In general, there is good agreement between the U.S. and Russian measurements. The AP8 Min trapped proton model predicts an average of 1.8 times the measured absorbed dose. The average quality factor determined from measured lineal energy, y, spectra using a tissue equivalent proportional counter (TEPC), is in good agreement with that derived from the high temperature peak in the 6LiF thermoluminescent detectors (TLDs). The radiation exposure in the mid-deck locker from neutrons below 1 MeV was 2.53 +/- 1.33 microSv/day. The absorbed dose rates measured using a tissue equivalent proportional counter, were 171.1 +/- 0.4 and 127.4 +/- 0.4 microGy/day for trapped particles and galactic cosmic rays, respectively. The combined dose rate of 298.5 +/- 0.82 microGy/day is about a factor of 1.4 higher than that measured using TLDs. The westward longitude drift of the South Atlantic Anomaly (SAA) is estimated to be 0.22 +/- 0.02 degrees/y. We evaluated the effects of spacecraft attitudes on TEPC dose rates due to the highly anisotropic low-earth orbit proton environment. Changes in spacecraft attitude resulted in dose-rate variations by factors of up to 2 at the location of the TEPC.     

Search for hydrocarbons by the method of induced seismoacoustic emission in wells

Regular specific features have been observed for the first time in the response of a fluid-saturated porous medium to a high-intensity seismoacoustic field. Experimental investigations show that the observed behavior can serve as a basis for a new effective complex technology capable of detecting hydrocarbons and water in the near-well zone and selectively restoring the fluid conductivity in oil pools.