18,596 research outputs found

    The global characteristics of atmosphere emissions in the lower thermosphere and their aeronomic implications

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    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

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    Night-time photometer measurements of ozone concentration at high altitud

    Analytic structure of Bloch functions for linear molecular chains

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    This paper deals with Hamiltonians of the form H=-{\bf \nabla}^2+v(\rr), with v(\rr) periodic along the zz direction, v(x,y,z+b)=v(x,y,z)v(x,y,z+b)=v(x,y,z). The wavefunctions of HH are the well known Bloch functions \psi_{n,\lambda}(\rr), with the fundamental property ψn,λ(x,y,z+b)=λψn,λ(x,y,z)\psi_{n,\lambda}(x,y,z+b)=\lambda \psi_{n,\lambda}(x,y,z) and ∂zψn,λ(x,y,z+b)=λ∂zψn,λ(x,y,z)\partial_z\psi_{n,\lambda}(x,y,z+b)=\lambda \partial_z\psi_{n,\lambda}(x,y,z). We give the generic analytic structure (i.e. the Riemann surface) of \psi_{n,\lambda}(\rr) and their corresponding energy, En(λ)E_n(\lambda), as functions of λ\lambda. We show that En(λ)E_n(\lambda) and ψn,λ(x,y,z)\psi_{n,\lambda}(x,y,z) are different branches of two multi-valued analytic functions, E(λ)E(\lambda) and ψλ(x,y,z)\psi_\lambda(x,y,z), with an essential singularity at λ=0\lambda=0 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

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    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

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    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

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    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

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    Application of numerical integration procedures to restricted three-body proble

    Operations and single particle interferometry

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    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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