Results 21 to 30 of about 617,536 (282)

DIPOLE ANTENNAS WITH A SECTOR-SHAPED RADIATION PATTERN [PDF]

Radio Physics and Radio Astronomy
Subject and Purpose. The directivity characteristics of a dipole antenna when it is placed above and parallel to a perfectly conducting screen of rectangular shape are considered, aiming to theoretically study dipole antennas with sector-shaped radiation
M. M. Gorobets, N. P. Yeliseyeva, S. L. Berdnyk, O. M. Horobets   +3 more
doaj   +1 more source

Improving the Directionality of Low-Frequency Acoustic Radiation by a Finite Array of Quadrupolar Sources with Acoustic Metamaterials

Crystals, 2023
Manipulating radiation patterns is challenging, especially at low frequencies. In this paper, we demonstrate that acoustic metamaterials arranged as an array of quadrupoles remarkably improve the directionality of acoustic radiation at low frequencies ...
Qinglei Zeng, Shenlian Gao, Yun Lai, Xiaozhou Liu   +3 more
doaj   +1 more source

Relação entre a precipitação no setor leste do nordeste do Brasil e a temperatura da superfície nos oceanos Atlântico e Pacífico Relationship between the rainfall in eastern Northeast Brazil and the sea surface temperature in the Atlantic and Pacific oceans

Revista Brasileira de Engenharia Agrícola e Ambiental, 2000
Objetivou-se, com este estudo, relacionar a precipitação no setor leste do Nordeste do Brasil (NEB) com a Temperatura da Superfície do Mar (TSM) nos oceanos Atlântico (área do Dipolo) e Pacífico, no período de 1945 a 1985.
Geber Barbosa de A. Moura, José Oribe Rocha de Aragão, Francinete Francis Lacerda, José Zanon de O. Passavante   +3 more
doaj   +1 more source

Fully Planar Dual-Polarized Broadband Antenna for 3G, 4G and Sub 6-GHz 5G Base Stations

IEEE Access, 2020
A fully planar dual polarized radiating element with internal embedded coupled dipoles is presented in this paper. The inclusion of these elements allows achieving three different goals: firstly, an extension of the bandwidth towards lower frequencies ...
Sergio Martin-Anton, Daniel Segovia-Vargas   +1 more
doaj   +1 more source

Dynamic theory of the nuclear collective model [PDF]

, 1964
The rotation-vibration model and the hydrodynamic dipole-oscillation model are unified. A coupling between the dipole oscillations and the quadrupole vibrations is introduced in the adiabatic approximation. The dipole oscillations act as a "driving force"
Danos, Michael, Greiner, Walter
core   +1 more source

Double Giant Dipole Resonance in ^{208}Pb [PDF]

, 1997
Double-dipole excitations in ^{208}Pb are analyzed within a microscopic model explicitly treating 2p2h-excitations. Collective states built from such 2p2h-excitations are shown to appear at about twice the energy of the isovector giant dipole resonance ...
A. Winther, C. A. Bertulani, H. Emling, J. Ritman, J. Wambach, K. Alder, K. Boretzky, Ph. Chomaz, R. Schmidt, S. Mordechai, S. Mordechai, S. Nishizaki, S. Nishizaki, S. Typel, S. Veyssiere, T. Aumann, V. Yu. Ponomarev   +16 more
core   +4 more sources

Test Reduction for Power Density Emitted by Handset mmWave Antenna Arrays

IEEE Access, 2021
The exposure to electromagnetic field (EMF) from phased antenna arrays integrated into wireless devices operating at the millimeter-wave (mmWave) part of the spectrum should be evaluated in terms of power density (PD).
Stanislav Stefanov Zhekov, Kun Zhao, Ondrej Franek, Shuai Zhang   +3 more
doaj   +1 more source

Octahedral Tilt Instability of ReO_3-type Crystals [PDF]

, 2005
The octahedron tilt transitions of ABX_3 perovskite-structure materials lead to an anti-polar (or antiferroelectric) arrangement of dipoles, with the low temperature structure having six sublattices polarized along various crystallographic directions. It
A. M. Glazer, C. Kittel, Clare P. Grey, F. Jona, J. D. Jackson, M. E. Lines, P. M. Woodward, P. M. Woodward, Philip B. Allen, R. C. Shannon, Santanu Chaudhuri, W. Känzig, Yiing-Rei Chen   +12 more
core   +1 more source

Multiple Dipole Source Position and Orientation Estimation Using Non-Invasive EEG-like Signals

Sensors, 2023
The problem of precisely estimating the position and orientation of multiple dipoles using synthetic EEG signals is considered in this paper. After determining a proper forward model, a nonlinear constrained optimization problem with regularization is ...
Saina Namazifard, Kamesh Subbarao
doaj   +1 more source

Dipole-dipole dispersion interactions between neutrons

, 2017
We investigate the long-range interactions between two neutrons utilizing recent data on the neutron static and dynamic electric and magnetic dipole polarizabilities.
Babb, James F., Higa, Renato, Hussein, Mahir S.   +2 more
core   +2 more sources