A very-wide-band dummy load for measuring power at very-high and ultra-high frequencies

1955 ◽  
Vol 102 (1) ◽  
pp. 96-98 ◽  
Author(s):  
W. Hersch
Keyword(s):  
Wide Band ◽  
High Frequencies ◽  
Dummy Load ◽  
Very High

Chaotic Synchronization in Ultra-Wide-Band Communication and Positioning Systems

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
J. C. Chedjou ◽  
K. Kyamakya ◽  
W. Mathis ◽  
I. Moussa ◽  
A. Fomethe ◽  
...  
Keyword(s):  
Phase Synchronization ◽  
Coupled System ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Analog Simulation ◽  
Positioning Systems ◽  
High Frequencies ◽  
Coupling Parameters ◽  
Very High Frequencies ◽  
Very High

This paper investigates synchronization transitions in a system of coupled Rössler type nonidentical self-sustained chaotic oscillators. The interest in Rössler oscillators is due to their chaotic behavior at very high frequencies. Both phase synchronization and lag synchronization are analyzed numerically considering coupling parameters. It is shown that both types of synchronization can be achieved by monitoring the coupling parameters. The advantage of using one parameter to ensure both types of synchronization is found in practice. Another advantage of monitoring only one resistor is found in the accuracy of results. One resistor is used to predict the boundaries of the control resistor for the occurrence of each type of synchronization. An experimental study of the synchronization is carried out in this paper. An appropriate electronic circuit describing the coupled oscillators is designed and realized. Experimental wave forms in the drive and response systems are obtained and their comparison done to confirm the achievement of synchronization. The analog simulation is advantageous to analyze the behavior of the coupled system at very high frequencies at appropriate time scaling and offers the possibility of using our coupled system for ultra-wide-band applications.

VERY HIGH-ORDER SPATIALLY IMPLICIT SCHEMES FOR COMPUTATIONAL ACOUSTICS ON CURVILINEAR MESHES

2001 ◽  
Vol 09 (04) ◽  
pp. 1259-1286 ◽  
Author(s):  
MIGUEL R. VISBAL ◽  
DATTA V. GAITONDE
Keyword(s):  
Three Dimensional ◽  
Radiation Condition ◽  
Higher Order ◽  
High Order ◽  
High Frequencies ◽  
Decomposition Strategies ◽  
The Impact ◽  
Spurious Modes ◽  
Very High ◽  
Computational Strategy

A high-order compact-differencing and filtering algorithm, coupled with the classical fourth-order Runge–Kutta scheme, is developed and implemented to simulate aeroacoustic phenomena on curvilinear geometries. Several issues pertinent to the use of such schemes are addressed. The impact of mesh stretching in the generation of high-frequency spurious modes is examined and the need for a discriminating higher-order filter procedure is established and resolved. The incorporation of these filtering techniques also permits a robust treatment of outflow radiation condition by taking advantage of energy transfer to high-frequencies caused by rapid mesh stretching. For conditions on the scatterer, higher-order one-sided filter treatments are shown to be superior in terms of accuracy and stability compared to standard explicit variations. Computations demonstrate that these algorithmic components are also crucial to the success of interface treatments created in multi-domain and domain-decomposition strategies. For three-dimensional computations, special metric relations are employed to assure the fidelity of the scheme in highly curvilinear meshes. A variety of problems, including several benchmark computations, demonstrate the success of the overall computational strategy.

An ammeter for very high frequencies

1930 ◽  
Vol 68 (401) ◽  
pp. 556-559
Author(s):  
C.L. Fortescue ◽  
L.A. Moxon
Keyword(s):  
High Frequencies ◽  
Very High Frequencies ◽  
Very High

scholarly journals Idiotypic analysis of potential and available repertoires in the arsonate system.

1984 ◽  
Vol 160 (1) ◽  
pp. 1-11 ◽  
Author(s):  
M Slaoui ◽  
O Leo ◽  
J Marvel ◽  
M Moser ◽  
J Hiernaux ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
B Cells ◽  
Keyhole Limpet Hemocyanin ◽  
High Frequencies ◽  
Specific Subset ◽  
A Minor ◽  
Very High Frequencies ◽  
Very High ◽  
Limiting Dilution

We have shown that, by suitable idiotypic manipulation, BALB/c mice can express the major cross-reactive idiotype (CRI) of A/J mice in response to azophenylarsonate (Ars). In order to know if the CRIA idiotype is present in the potential repertoire of BALB/c before any intentional selection, we used polyclonal activation in vitro and limiting dilution analysis. The readout was done with two monoclonal anti-CRIA antibodies that recognize distinct idiotopes on a CRIA+ A/J germline-encoded monoclonal antibody. We studied the frequency of CRIA+ lipopolysaccharide (LPS)-reactive cells in the spleens of nonimmune and immune A/J mice and in the spleens of naive and manipulated (i.e., producing CRIA+ antibodies) BALB/c mice. A/J and BALB/c naive individuals presented very high frequencies of Ars-specific B cells while the frequency of CRIA+ B cells was only a minor subset (0.5%) of the total Ars-specific subset in the two strains. When A/J mice were immunized with Ars-keyhole limpet hemocyanin, a clear preferential expansion of the CRIA+ minor subset of A/J mice was observed (100x). No such enhancement was observed in BALB/c mice similarly treated. Manipulated BALB/c mice presented a higher frequency of CRIA+ anti-Ars B cells than naive or antigen-immunized BALB/c individuals.

scholarly journals Prediction of noise from wind turbines: theoretical and experimental study

2018 ◽  
pp. 34-41 ◽  
Author(s):  
Carlos Alberto Echeverri-Londoño ◽  
Alice Elizabeth González Fernández
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Sound Pressure ◽  
Prediction Method ◽  
Wide Band ◽  
Propagation Models ◽  
Low Frequencies ◽  
High Frequencies ◽  
Wind Speeds ◽  
Sound Pressure Levels

Several noise propagation models used to calculate the noise produced by wind turbines have been reported. However, these models do not accurately predict sound pressure levels. Most of them have been developed to estimate the noise produced by industries, in which wind speeds are less than 5 m/s, and conditions favor its spread. To date, very few models can be applied to evaluate the propagation of sound from wind turbines and most of these yield inaccurate results. This study presents a comparison between noise levels that were estimated using the prediction method established in ISO 9613 Part 2 and measured levels of noise from wind turbines that are part of a wind farm currently in operation. Differences of up to 56.5 dBZ, with a median of 29.6 dBZ, were found between the estimated sound pressure levels and measured levels. The residual sound pressure levels given by standard ISO 9613 Part 2 for the wind turbines is larger for high frequencies than those for low frequencies. When the wide band equivalent continuous sound pressure level is expressed in dBA, the residual varies between −4.4 dBA and 37.7 dBA, with a median of 20.5 dBA.

A Genetically Marked I Element in Drosophila melanogaster Can Be Mobilized When ORF2 Is Provided in trans

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 267-275
Author(s):  
Isabelle Busseau ◽  
Sophie Malinsky ◽  
Maria Balakireva ◽  
Marie-Christine Chaboissier ◽  
Danielle Teninges ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Reverse Transcriptase ◽  
Germ Line ◽  
Ltr Retrotransposons ◽  
Low Frequencies ◽  
High Frequencies ◽  
In Trans ◽  
Very High Frequencies ◽  
Very High

Abstract I factors in Drosophila melanogaster are non-LTR retrotransposons similar to mammalian LINEs. They transpose at very high frequencies in the germ line of SF females resulting from crosses between reactive females, devoid of active I factors, and inducer males, containing active I factors. The vermilion marked IviP2 element was designed to allow easy phenotypical screening for retrotransposition events. It is deleted in ORF2 and therefore cannot produce reverse transcriptase. IviP2 can be mobilized at very low frequencies by actively transposing I factors in the germ line of SF females. This paper shows that IviP2 can be mobilized more efficiently in the germ line of strongly reactive females in the absence of active I factors, when it is trans-complemented by the product of ORF2 synthesized from the hsp70 heat-shock promoter. This represents a promising step toward the use of marked I elements to study retrotransposition and as tools for mutagenesis.

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