scholarly journals Modulation Model of High Frequency Band Radar Backscatter by the Internal Wave Based on the Third-Order Statistics

2017 ◽  
Vol 9 (5) ◽  
pp. 501 ◽  
Author(s):  
Pengzhen Chen ◽  
Lei Liu ◽  
Xiaoqing Wang ◽  
Jinsong Chong ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Internal Wave ◽  
Order Statistics ◽  
Frequency Band ◽  
High Frequency ◽  
High Frequency Band ◽  
Third Order ◽  
Radar Backscatter ◽  
The Third ◽  
Modulation Model

Observations on the energy balance of internal waves during JASIN

1983 ◽  
Vol 308 (1503) ◽  
pp. 427-444 ◽  
Keyword(s):  
Internal Wave ◽  
Frequency Band ◽  
Wave Energy ◽  
High Frequency ◽  
Energy Sources ◽  
Buoyancy Frequency ◽  
High Frequency Band ◽  
Local Surface ◽  
Local Mean ◽  
Principal Energy

Depth-integrated horizontal kinetic energy (HKE) in the frequency band 0.1-4 cycles per hour is used to estimate the time variation at one site of internal wave energy over a 40 day period during JASIN 1978. The HKE smoothed over three days varies from 400 to 1500J m -2 . The canonical Garrett-Munk total energy of 3800J m -2 would provide about 1400J m -2 of hke in this high frequency band; a scaled-down estimate based on local mean buoyancy frequency and water depth suggests 450J m -2 . The first part of the record (1 to about 16 August) slowly grows then decays in energy to the record minimum at rates between 0.6 and — 1 mW m -2 , followed by about 11 days of sporadic growth and decay at rates between 3 and — 0.8 mW m -2 to the record maximum, and then a week of fast decay at rates between — 2 and — 1 mW m -2 . A speculative balance of possible energy sources, sinks, and advection/ propagation is discussed. The tentative conclusion is that horizontal shears and wind stress fluctuations are the principal energy sources, the latter possibly via interacting surface waves, and that loss of energy from the internal wave continuum to the near-inertial band may be a major sink of hke. A surprising heuristic correspondence is shown between the amplitude of the local surface wavefield, and the internal wave energy 11 days later.

The SIRIO satellite, 1968––1977: Between scientific engagement and managerial inexperience

2004 ◽  
Vol 34 (2) ◽  
pp. 371-398
Author(s):  
LUCIA ORLANDO
Keyword(s):  
International Economic ◽  
Organizational Structure ◽  
Frequency Band ◽  
High Frequency ◽  
Aerospace Industry ◽  
Space Research ◽  
High Frequency Band ◽  
Political Uncertainty ◽  
The 1960S ◽  
Super High Frequency

ABSTRACT: The story of the first Italian communications satellite, SIRIO, started in 1968, after the failure of the European project for the vector ELDO-PAS. The story up to the launch in 1977 involved the encumbering legacy of the San Marco satellite's success in the 1960s, political uncertainty in Italy, international economic crises of the 1970s, an overtly complex management system, and an inexperienced aerospace industry. Despite these handicaps, SIRIO won the race with its nearest competitor, the European satellite OTS, which had a similar research aim in the super high frequency band. In addition to collecting a large amount of useful data, SIRIO catalyzed the process for developing an improved organizational structure for Italian space research.

Nanoelectromagnetic of the N-doped single wall carbon nanotube in the extremely high frequency band

Nanoscale ◽  
2017 ◽  
Vol 9 (37) ◽  
pp. 14192-14200 ◽  
Author(s):  
B. Aïssa ◽  
M. Nedil ◽  
J. Kroeger ◽  
M. I. Hossain ◽  
K. Mahmoud ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Frequency Band ◽  
Electromagnetic Interference ◽  
High Frequency ◽  
High Electrical Conductivity ◽  
High Frequency Band ◽  
High Demand ◽  
Extremely High Frequency ◽  
Minimal Thickness

Materials offering excellent mechanical flexibility, high electrical conductivity and electromagnetic interference (EMI) attenuation with minimal thickness are in high demand, particularly if they can be easily processed into films.

scholarly journals A Compact Printed Monopole Antenna for WiMAX/WLAN and UWB Applications

2018 ◽  
Vol 10 (12) ◽  
pp. 122 ◽  
Author(s):  
Zubin Chen ◽  
Baijun Lu ◽  
Yanzhou Zhu ◽  
Hao Lv
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Field Work ◽  
Monopole Antenna ◽  
Center Frequency ◽  
High Frequency Band ◽  
Work Requirements ◽  
Printed Monopole Antenna ◽  
Printed Monopole ◽  
Uwb Applications

In this paper, a printed monopole antenna design for WiMAX/WLAN applications in cable-free self-positioning seismograph nodes is proposed. Great improvements were achieved in miniaturizing the antenna and in widening the narrow bandwidth of the high-frequency band. The antenna was fed by a microstrip gradient line and consisted of a triangle, an inverted-F shape, and an M-shaped structure, which was rotated 90° counterclockwise to form a surface-radiating patch. This structure effectively widened the operating bandwidth of the antenna. Excitation led to the generation of two impedance bands of 2.39–2.49 and 4.26–7.99 GHz for a voltage standing wave ratio of less than 2. The two impedance bandwidths were 100 MHz, i.e., 4.08% relative to the center frequency of 2.45 GHz, and 3730 MHz, i.e., 64.31% relative to the center frequency of 5.80 GHz, covering the WiMAX high-frequency band (5.25–5.85 GHz) and the WLAN band (2.4/5.2/5.8). This article describes the design details of the antenna and presents the results of both simulations and experiments that show good agreement. The proposed antenna meets the field-work requirements of cable-less seismograph nodes.

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