摘要:

Nine rectangular prisms of hydro‐thermally‐grown synthetic quartz crystals with 900 atomic ppm H+were loaded in compression at 1400 bars stress and temperatures between 403 and 764°C. Theaandcdirections were at 45° to the compression direction, and the slip system[0001]appears to operate over the entire range of temperatures. The strain vs. time curves were sigmoidal in shape; an incubation stage of accelerating creep rates was followed by a hardening stage in which creep rates decreased with time. The creep rate (⋵) vs. temperature (T) data were found to fit very well an Arrehenius law of the formA exp (−E* / RT)where E* is the activation energy for creep. E* is 38.9 ± 2.1 kcal/mole in the α field and 14.3 ± 4.7 kcal/mole in the β field. An offset in the maximum strain rates occurs at the transition temperature, with the β phase creeping at less than half the rate of the α phase. It is suggested that the changes in creep parameters are due to the effects of the inversion on the rates of oxygen diffusion associated with the dissolved water, which hydrolytically weakens the crystals. The α‐β transformation involves rather subtle structural changes. No bond breaking occurs and the change in density is rather small. The transformations responsible for the transition zone of the mantle are reconstructive (involving extensive bond breaking and complete atomic reorganization) and the density changes are large. Thus the potential for large effects of these transformations on creep propert

ISSN:0094-8276    

DOI:10.1029/GL004i003p00097

年代:1977

数据来源: WILEY

摘要:

Data are provided on the May 1976 northern hemispheric background concentrations of 13 halocarbons, SF6, and N2O. A model is developed that permits an easy comparison of atmospheric lifetimes, emissions, and ambient concentrations. Our measurements indicate that atmospheric levels of CCl2F2(F12) and CCl3F(F11) are consistent with an average residence time of 50 (±33) and 36 (±8) years respectively. The tropospheric lifetimes of reactive species such as CH3CCl3, CHCl3, and C2Cl4are found to be 7.2 (±1.2), 1.7 (±0.4), and 0.4 (±0.1) years respectively. These longer lifetimes of tropospherically reactive species are inconsistent with the existing knowledge of atmospheric chemistry. Our conservative analysis of atmospheric halocarbon data shows that average HO concentrations must be 2 to 6 × 105HO/ml instead of the accepted range of 10 to 30 × 105HO/ml. These lower HO values tend to resolve the apparent discrepancies in the biospheric budgets and distribution of chlorinated hydrocarbons and CO. The tropospheric and stratospheric implications of reduced HO levels are dis

ISSN:0094-8276    

DOI:10.1029/GL004i003p00101

年代:1977

数据来源: WILEY

摘要:

Spectral analysis of winter temperatures in Tokyo from 1443‐1970, based to 1870 on Lake Suwa freezing dates and since then on observations, shows significant contributions to variance in the 2.1, 3.0, 10.9 and 21.7 years bands. Consecutive thirty year means show very little variation. The coldest period was between 1489 and 1528. There is no notable variation during the so‐called Maunder sunspot mini

ISSN:0094-8276    

DOI:10.1029/GL004i003p00105

年代:1977

数据来源: WILEY

摘要:

High resolution energy spectra of the flux of precipitating photoelectrons which arise from solar illumination of the area near the magnetic conjugate point have been measured with the Photoelectron Spectrometer Experiment on the Atmosphere Explorer C Spacecraft. Conjugate photoelectrons have been observed when the spacecraft was well away from the terminator at local solar zenith angles up to 160°. The shape of the observed electron energy spectrum is almost identical to that reported for high altitude photoelectron spectra from the Atmosphere Explorer E Spacecraft by Doering et al., 1976. Identification of the residual spectral features in the energy spectra of the conjugate photoelectrons shows that to within the experimental uncertainty of ± 1 eV, the photoelectrons from the magnetic conjugate point have not experienced any acceleration. The magnitude of the observed conjugate photoelectron flux varies considerably between passes, but in some cases the 250 km flux has been observed to be as much as half of the magnitude of the escaping photoelectron flux at 300 km near the sunlit conjugate point. Observations of the precipitating and backscattered flux provide a direct measurement of the low energy (10 eV ‐ 60 eV) electron alb

ISSN:0094-8276    

DOI:10.1029/GL004i003p00109

年代:1977

数据来源: WILEY

摘要:

The radio beacon signals on 40 MHz, and 140 MHz and 360 MHz from ATS‐6 satellite at 34°E longitude, received at Ootacamund, India (11.43°N, 76.70°E, dip 4°N) are found to have intense scintillations during daytime on some occasions. These daytime scintillation events are not associated with the q type of sporadic E layer as seen at Kodaikanal (10.23°N, 77.49°E, 3.5N) but are due to the intense ionisation patches in the E region indicated by occurrence on the ionograms of the non q type i.e. either high or flat type of sporadic E layer which either shows multiple reflections or blankets the higher refl

ISSN:0094-8276    

DOI:10.1029/GL004i003p00113

年代:1977

数据来源: WILEY

摘要:

Infrared solar observations made by balloon at 27.9 km altitude in April 1976, and from the ground station of the Jungfraujoch, Switzerland, in October 1976, have confirmed the presence of hydrofluoric acid in the upper stratosphere. An average value of (3.6 ± .7) × 10−10ppv has been deduced for the concentration of HF above 27.9 km. The comparison between the ground‐and the balloon observations tends to indicate that over 50% of the total atmospheric HF is located above 25 km alt

ISSN:0094-8276    

DOI:10.1029/GL004i003p00117

年代:1977

数据来源: WILEY

摘要:

Some theories of Jovian decametric and Terrestrial kilometric radiations require that the emissions escape at the plasma frequency in the magnetospheres of these planets. This requirement creates difficulties in explaining a number of characteristics of these radiations. It seems that the problems may be overcome by invoking wave‐wave interaction between Z‐mode waves, and it is suggested that an estimate of Saturn's magnetic field on the basis of the observed hectometric radiation could be errone

ISSN:0094-8276    

DOI:10.1029/GL004i003p00121

年代:1977

数据来源: WILEY

摘要:

It is shown that the lower‐hybrid‐drift instability can be unstable over a large region of the magnetotail where collisionless reconnection is expected to occur. For typical quiescent tail parameters the instability threshold is much lower than the ion acoustic instability. Preliminary considerations indicate that it can produce anomalous resistivity substantially larger than classical, reconnection rates of the order 10−1VA, electromagnetic noise is the frequency range ωLH<ω ≪ Ωeand field aligned relativistic elect

ISSN:0094-8276    

DOI:10.1029/GL004i003p00125

年代:1977

数据来源: WILEY