14,516 research outputs found
Some results concerning the principal airglow lines as measured from the OGO-II satellite
OGO-II satellite measurement of principal airglow line
The global characteristics of atmosphere emissions in the lower thermosphere and their aeronomic implications
The green line of atomic oxygen and the Herzberg bands of molecular oxygen as observed from the OGO-4 airglow photometer are discussed in terms of their spatial and temporal distributions and their relation to the atomic oxygen content in the lower thermosphere. Daily maps of the distribution of emissions show considerable structure (cells, patches, and bands) with appreciable daily changes. When data are averaged over periods of several days in length, the resulting patterns have occasional tendencies to follow geomagnetic parallels. The Seasonal variations are characterized by maxima in both the Northern and Southern Hemispheres in October, with the Northern Hemisphere having substantially higher emission rates. Formulae are derived relating the vertical column emission rates of the green line and the Herzberg bands to the atomic oxygen peak density. Global averages for the time period for these data (August 1967 to January 1968), when converted to maximum atomic oxygen densities near 95 km, have a range of 2.0 x 10 to the 11th power/cu cm 2.7 x 10 to the 11th power/cu cm
A night-time measurement of ozone above 40 km
Night-time photometer measurements of ozone concentration at high altitud
Behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming
The behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming has been studied principally by use of data from the airglow photometers on the OGO-4 satellite. It was found that during the late stages of a major warming, both emissions increase appreciably, with the sodium emission returning to normal levels prior to the decrease in hydroxyl emission. The emission behaviors are attributed to temperature and density variations from 70 to 94 km, and a one-dimensional hydrostatic model for that altitude range is used to calculate the effects on the emissions and on the mesospheric ozone densities
Analytic structure of Bloch functions for linear molecular chains
This paper deals with Hamiltonians of the form H=-{\bf \nabla}^2+v(\rr),
with v(\rr) periodic along the direction, . The
wavefunctions of are the well known Bloch functions
\psi_{n,\lambda}(\rr), with the fundamental property
and
. We give the generic analytic structure
(i.e. the Riemann surface) of \psi_{n,\lambda}(\rr) and their corresponding
energy, , as functions of . We show that
and are different branches of two multi-valued
analytic functions, and , with an essential
singularity at and additional branch points, which are generically
of order 1 and 3, respectively. We show where these branch points come from,
how they move when we change the potential and how to estimate their location.
Based on these results, we give two applications: a compact expression of the
Green's function and a discussion of the asymptotic behavior of the density
matrix for insulating molecular chains.Comment: 13 pages, 11 figure
The application of a numerical integration procedure developed by erwin fehlberg to the restricted problem of three bodies
Application of numerical integration procedures to restricted three-body proble
The stratcom 8 effort
The ozone-nitrogen oxides ultraviolent flux interactions were investigated to obtain data on stratospheric photochemistry. The balloon, rocket, and aircraft operations are described along with the instruments, parameter measurements, and payloads
Propagators weakly associated to a family of Hamiltonians and the adiabatic theorem for the Landau Hamiltonian with a time-dependent Aharonov-Bohm flux
We study the dynamics of a quantum particle moving in a plane under the
influence of a constant magnetic field and driven by a slowly time-dependent
singular flux tube through a puncture. The known adiabatic results do not cover
these models as the Hamiltonian has time dependent domain. We give a meaning to
the propagator and prove an adiabatic theorem. To this end we introduce and
develop the new notion of a propagator weakly associated to a time-dependent
Hamiltonian.Comment: Title and Abstract changed, will appear in Journal of Mathematical
Physic
A VLSI design for a systolic Viterbi decoder
A systolic Viterbi decoder for convolutional codes is developed. This decoder uses the trace-back method to reduce the amount of data needed to be stored in registers. It is shown that this new algorithm requires a smaller chip size and achieves a faster decoding time than other existing methods
Resonances Width in Crossed Electric and Magnetic Fields
We study the spectral properties of a charged particle confined to a
two-dimensional plane and submitted to homogeneous magnetic and electric fields
and an impurity potential. We use the method of complex translations to prove
that the life-times of resonances induced by the presence of electric field are
at least Gaussian long as the electric field tends to zero.Comment: 3 figure
- …