A theoretical study on the broad symmetric structure in the stimulated electromagnetic emission spectrum

1995 ◽  
Vol 100 (A2) ◽  
pp. 1639 ◽  
Author(s):  
J. Huang ◽  
S. P. Kuo ◽  
H. L. Zhou
Keyword(s):  
Emission Spectrum ◽  
Theoretical Study ◽  
Electromagnetic Emission ◽  
Symmetric Structure ◽  
Stimulated Electromagnetic Emission

Design and analysis of a novel seven-bar mechanical servo press with dual motors inputs

2016 ◽  
Vol 231 (20) ◽  
pp. 3855-3865
Author(s):  
Chen Liu ◽  
Sheng-Dun Zhao ◽  
Jing-Xiang Li
Keyword(s):  
Metal Forming ◽  
Theoretical Study ◽  
High Capacity ◽  
High Ratio ◽  
Measured Data ◽  
Servo Motor ◽  
Symmetric Structure ◽  
Servo Press ◽  
The Press ◽  
Dynamic Analyses

This paper proposes a novel high capacity servo press system with two servo motor inputs and high ratio force amplifier mechanism for metal forming. First, the press structure was expressed. The force amplifier was made of seven-bar mechanism which possesses quick-return character and high ratio force amplifier. The symmetric structure balanced the force in horizontal direction, and dispersed the forces on two transmission routes. In theoretical study of the new structure, kinematic and dynamic analyses were obtained by examining the geometry of the structure. The performance of press was discussed by example demonstration. Finally, the kinematic experiments and metal forming experiments were carried out on the prototype machine by using grating scale system. The measured data match the theoretical calculation well, which validates the feasibility of this new press mechanism.

Dependence of stimulated electromagnetic emission on the ionosphere and pump wave

1990 ◽  
Vol 95 (A10) ◽  
pp. 17233 ◽  
Author(s):  
T. B. Leyser ◽  
B. Thidé ◽  
H. Derblom ◽  
Å. Hedberg ◽  
B. Lundborg ◽  
...  
Keyword(s):  
Pump Wave ◽  
Electromagnetic Emission ◽  
Stimulated Electromagnetic Emission

scholarly journals An interferometer experiment to explore the aspect angle dependence of stimulated electromagnetic emission spectra

2005 ◽  
Vol 23 (1) ◽  
pp. 55-74 ◽  
Author(s):  
◽  
Yu. Yurik ◽  
La Hoz ◽  
◽  
◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Electromagnetic Emission ◽  
Density Fluctuations ◽  
Spectral Features ◽  
Langmuir Turbulence ◽  
Angular Structure ◽  
Frequency Spectra ◽  
Aspect Angle ◽  
Angle Dependence ◽  
Stimulated Electromagnetic Emission

Abstract. When the Earth's ionosphere is irradiated by a radiofrequency (RF) electromagnetic wave of sufficiently high power density and tuned to match a natural E- or F-region plasma frequency, ionospheric magnetoionic wave modes may be excited and may generate RF electromagnetic sideband waves via nonlinear interactions. These secondary emissions, which may then escape from the ionosphere, have been termed stimulated electromagnetic emission or SEE. The frequency spectra of this radiation has been studied extensively, and a number of characteristic spectral features have been identified and in some cases related to particular plasma processes. The separation in frequency between the RF pump and the harmonics of the local electron gyrofrequency is critical in determining the amount of anomalous absorption suffered by the pump wave and the spectral properties of the stimulated sidebands. The pump can excite electrostatic waves which do not propagate away but can in some cases be observed via radio-wave scattering from the electron density fluctuations associated with them. These enhanced density fluctuations are created by processes commonly referred to as upper-hybrid and Langmuir turbulence. Langmuir turbulence has been the subject of 930-MHz scattering observations with antenna scanning through several pre-selected angles between the geographic and geomagnetic zenith directions, and a preference for pointing angles between the Spitze angle and geomagnetic field-aligned was identified. Other phenomena, such as the generation of enhanced electron temperatures and artificial aurora, have more recently been shown to have special behavior at similar angles, near but apparently not quite at field-aligned. In view of this evidence for angular structure in several pump-induced effects, in light of the rich variety of SEE phenomena strongly dependent on the geomagnetic field via the frequency interval between the pump and the gyrofrequency harmonics, and in view of the not yet understood but complex relationship between electrostatic fluctuations and SEE, it is of interest to investigate experimentally whether a similar angular structure is present in the various spectral features of the SEE signals and to compare the results with radar and other observations of RF-pump-induced effects. To this end we describe a simple two-element radio interferometer designed to search for aspect angle dependence of SEE features. We present an example of the initial data produced by this system, and draw preliminary conclusions based on the example data.

scholarly journals A new upshifted spectral stimulated electromagnetic emission structure, observed between electron cyclotron harmonics

1997 ◽  
Vol 24 (13) ◽  
pp. 1647-1650 ◽  
Author(s):  
V. L. Frolov ◽  
E. N. Ermakova ◽  
L. M. Erukhimov ◽  
G. P. Komrakov ◽  
E. N. Sergeev ◽  
...  
Keyword(s):  
Electromagnetic Emission ◽  
Electron Cyclotron ◽  
Cyclotron Harmonics ◽  
Stimulated Electromagnetic Emission

Two-Component Nature of the Broad Up-shifted Maximum in Stimulated Electromagnetic Emission Spectra

1998 ◽  
Vol 81 (8) ◽  
pp. 1630-1633 ◽  
Author(s):  
V. L. Frolov ◽  
L. M. Ekukhimov ◽  
L. M. Kagan ◽  
G. P. Komrakov ◽  
E. N. Sergeev ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Electromagnetic Emission ◽  
Two Component ◽  
Stimulated Electromagnetic Emission
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