30,468 research outputs found
Low Voltage Floating Gate MOS Transistor Based Four-Quadrant Multiplier
This paper presents a four-quadrant multiplier based on square-law characteristic of floating gate MOSFET (FGMOS) in saturation region. The proposed circuit uses square-difference identity and the differential voltage squarer proposed by Gupta et al. to implement the multiplication function. The proposed multiplier employs eight FGMOS transistors and two resistors only. The FGMOS implementation of the multiplier allows low voltage operation, reduced power consumption and minimum transistor count. The second order effects caused due to mobility degradation, component mismatch and temperature variations are discussed. Performance of the proposed circuit is verified at ±0.75 V in TSMC 0.18 µm CMOS, BSIM3 and Level 49 technology by using Cadence Spectre simulator
Spin-charge and spin-orbital coupling effects on spin dynamics in ferromagnetic manganites
Correlation-induced spin-charge and spin-orbital coupling effects on spin
dynamics in ferromagnetic manganites are calculated with realistic parameters
in order to provide a quantitative comparison with experimental results for
spin stiffness, magnon dispersion, magnon damping, anomalous zone-boundary
magnon softening, and Curie temperature. The role of orbital degeneracy,
orbital ordering, and orbital correlations on spin dynamics in different doping
regimes is highlighted.Comment: 19 pages, 9 figure
Relationship between Horizontal Flow Velocity and Cell Lifetime for Supergranulation
A study of 50 supergranular cells obtained from SOHO Dopplergrams was
undertaken in order to investigate the relationship between the lifetime ()
and the horizontal flow velocity () of the cells. For this sample we find
that the two parameters are correlated with a relation and
is identified with the eddy turn-over time. This is in agreement with the
turbulent convective model of the solar atmosphere where the velocity spectrum
of supergranular field given by '' can be identified with
the Kolmogorov spectrum for the eddy size .Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
High Spectral Purity, Narrow Linewidth Laser Transmitter for Dial Measurements
A laser transmission with very high degree of spectral purity was described. Amplified Spontaneous Emission (ASE) dependence on the oscillator energy and the detuning away from the gain curve center are demonstrated. The effects of both finite laser linewidth and spectral purity on humidity measurements are experimentally demonstrated
Progress of research on water vapor lidar
Research is summarized on applications of stimulated Raman scattering (SRS) of laser light into near infrared wavelengths suitable for atmospheric monitoring. Issues addressed are conversion efficiency, spectral purity, optimization of operating conditions, and amplification techniques. A Raman cell was developed and built for the laboratory program, and is now available to NASA-Langley, either as a design or as a completed cell for laboratory or flight applications. The Raman cell has been approved for flight in NASA's DC-8 aircraft. The self-seeding SRS technique developed here is suggested as an essential improvement for tunable near-IR DIAL applications at wavelengths of order 1 micrometer or greater
Using indirect methods to understand the impact of forced migration on long-term under-five mortality.
Despite the large numbers of displaced persons and the often-lengthy periods of displacement, little is known about the impact of forced migration on long-term under-five mortality. This paper looks at the Brass Method (and adaptations of this method) and the Preceding Birth Technique in combination with a classification of women by their migration and reproductive histories, in order to study the impact of forced migration on under-five mortality. Data came from the Demography of Forced Migration Project, a study on mortality, fertility and violence in the refugee and host populations of Arua District, Uganda and Yei River District, Sudan. Results indicate that women who did not migrate in a situation of conflict and women who repatriated before the age of 15, had children with the highest under-five mortality rates compared with women who were currently refugees and women who repatriated after the age of 15
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