19,251 research outputs found
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
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
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
A VLSI architecture of a binary updown counter
A pipeline binary updown counter with many bits is developed which can be used in a variety of applications. One such application includes the design of a digital correlator for very long baseline interferometry (VLBI). The advantage of the presently conceived approach over the previous techniques is that the number of logic operations involved in the design of the binary updown counter can be reduced substantially. The architecture design using these methods is regular, simple, expandable and, therefore, naturally suitable for VLSI implementation
Some results concerning the principal airglow lines as measured from the OGO-II satellite
OGO-II satellite measurement of principal airglow line
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
Operations and single particle interferometry
Interferometry of single particles with internal degrees of freedom is
investigated. We discuss the interference patterns obtained when an internal
state evolution device is inserted into one or both the paths of the
interferometer. The interference pattern obtained is not uniquely determined by
the completely positive maps (CPMs) that describe how the devices evolve the
internal state of a particle. By using the concept of gluing of CPMs, we
investigate the structure of all possible interference patterns obtainable for
given trace preserving internal state CPMs. We discuss what can be inferred
about the gluing, given a sufficiently rich set of interference experiments. It
is shown that the standard interferometric setup is limited in its abilities to
distinguish different gluings. A generalized interferometric setup is
introduced with the capacity to distinguish all gluings. We also connect to
another approach using the well known fact that channels can be realized using
a joint unitary evolution of the system and an ancillary system. We deduce the
set of all such unitary `representations' and relate the structure of this set
to gluings and interference phenomena.Comment: Journal reference added. Material adde
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