Modelling and Numerical Analysis for High Frequency Characteristics of Laminated Galfenol Based on Eddy-Current

2014 ◽  
Author(s):  
Yimin Tan ◽  
Zuguang Zhang ◽  
Jean Zu
Keyword(s):  
Eddy Current ◽  
High Frequency ◽  
Power Efficiency ◽  
Maxwell Equations ◽  
High Strain ◽  
Ferromagnetic Material ◽  
Frequency Characteristics ◽  
Frequency Range ◽  
Critical Criterion ◽  
The Relationship

Galfenol, a novel magnetostrictive and ferromagnetic material, has been employed in various applications because of the material’s outstanding mechanical properties. For high frequency applications, the energy loss of eddy-current is a critical criterion because this loss not only reduces the power efficiency for Galfenol material, but also rapidly generates large amounts of heat that can destabilize the system. While laminating ferromagnetic material has been proved to be an effective way that minimises eddy-current, the objective of this research is to investigate the laminated Galfenol material’s plausibility in high frequency applications. For the prescribed geometry, an accurate model for the generated eddy-current is derived based on the Maxwell equations. Combining a built magnetic coupled dynamic model, the relationship between the strain response and the applied magnetic field is derived under high frequency conditions. The simulative results of the laminated Galfenol rods are compared to those rods without laminations. The comparison shows that the laminated Galfenol rod exhibits a milder hysteresis than the non-laminated Galfenol rod. Furthermore, the laminated Galfenol rod is able to maintain a high strain output with a broader frequency range compared to the non-laminated Galfenol rod. This work proves that laminating Galfenol rods are capable of restricting the generation of eddy-current and improving high frequency characteristics significantly.

The Noise Characteristics Research in Subway Cars

2014 ◽  
Vol 1051 ◽  
pp. 431-434
Author(s):  
Jian Hui Tian ◽  
Lian Jian ◽  
Bing Li
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Noise Spectrum ◽  
Frequency Range ◽  
Noise Characteristics ◽  
Spectrum Distribution ◽  
Spectrum Characteristics ◽  
Relationship Of ◽  
The Relationship

The noise of different points in four sections of Shenzhen subway was tested by this paper. Real-time SPL and noise spectrum distribution curves at bogie were given, while the equivalent SPL curve was also shown. The relationship of subway speed and noise SPL was investigated. The regular of noise spectrum characteristics and SPL was obtained. The results show that the noise SPL increases with the increase of the speed. Looking from the frequency range, the frequency corresponding to larger noise SPL amplitude mainly concentrates in the lower frequency while the subway stopping, the frequency corresponding to larger noise SPL amplitude mainly concentrates in high frequency while the subway running.

scholarly journals UHF PD Experiments on Real Power Transformer and its Frequency Characteristics Results

2016 ◽  
Vol 6 (1) ◽  
pp. 906-912
Author(s):  
H. Fan ◽  
J. Hu ◽  
H. Liu ◽  
Y. Yin ◽  
M. Danikas
Keyword(s):  
High Frequency ◽  
Power Transformer ◽  
Detection System ◽  
Wavelet Packet ◽  
Low Frequency ◽  
Recognition System ◽  
Frequency Range ◽  
Real Power ◽  
The Relationship ◽  
Detection And Recognition

A number of methods have been used in partial discharge (PD) detection and recognition. Among these methods, ultra-high frequency (UHF) detection and recognition based on a single signal have attracted much attention. In this paper, a UHF PD detection system is built, and samples are acquired through experiments on a real power transformer. The received signal is decomposed into different frequency ranges through wavelet packet decomposition (WPD). In each frequency range, a pattern recognition neural network is built, and then the relationship between the information in that frequency range and PD type is described. By comparing the recognition accuracy of these networks, frequency range selection is optimized. In this specific case (the specific transformer, PD sources, and UHF sensors), results show that low frequency (156.25 MHz to 312.5 MHz) and high frequency ranges (1093.75 MHz to 1250 MHz) contain the most information for recognition. If a PD detection recognition system is to be designed, then the performance around these frequency ranges should be given attention.

Improvement in the Acoustic Characteristics of the Micro Speaker by Changing Thickness and Foaming Ratio of the Diaphragm

2013 ◽  
Vol 718-720 ◽  
pp. 1310-1315
Author(s):  
Takeshi Nomoto ◽  
Takeru Moriuchi ◽  
Toru Fujii
Keyword(s):  
Fem Analysis ◽  
Cellular Phone ◽  
Frequency Characteristics ◽  
Experimental Result ◽  
Frequency Range ◽  
Acoustic Characteristics ◽  
Aluminum Sheets ◽  
Magnet Coil ◽  
Natural Frequency Analysis ◽  
The Relationship

The typical speaker for cellular phone is composed of magnet, coil, base-film and diaphragm with a structure that laminated a foam sheet and aluminum sheets. A heterogeneous foam sheet which has an uneven elastic modulus was used for a conventional diaphragm, and it reduced an acoustic performance of a conventional speaker. Recently a homogeneous and thin foam sheet was newly developed. The purpose of this study is to improve the acoustic characteristics of the micro speaker by changing thickness and foaming ratio of the newly developed foam sheet. Frequency characteristics and sound pressure level (SPL) were measured by changing foaming ratio of the foam sheet from 2.5 to 5.0 and thickness of the foam sheet from 0.15 mm to 0.30 mm. To clarify the relationship between the design parameter of foam sheet and the frequency characteristics of the micro speaker, natural frequency analysis using finite element method (FEM) was performed. The result of FEM analysis was also compared with the experimental result using a laser doppler velocimetry sensor. It was found that the widest reproducible frequency range was obtained when the foam sheet was used 0.30 mm of thickness and 5.0 of foaming ratio. The reproducible frequency range spread out 15% in comparison with that of a conventional micro speaker.

Core Losses Separation of Amorphous Alloy Core

2016 ◽  
Vol 849 ◽  
pp. 91-94
Author(s):  
Shan Hong Li ◽  
Li Jun Li ◽  
De Ren Li ◽  
Zhi Chao Lu
Keyword(s):  
Amorphous Alloy ◽  
Eddy Current ◽  
High Frequency ◽  
Low Frequency ◽  
Eddy Current Loss ◽  
Hysteresis Loss ◽  
Frequency Range ◽  
Current Loss ◽  
Core Losses ◽  
Additional Loss

In this paper, the core losses of Fe80Si9B11, Fe78Si9B13 amorphous alloy cores were separated to investigate the behaviors of hysteresis loss, eddy current loss and additional loss in high frequency range. The results showed that the losses of amorphous alloy core were mainly composed of hysteresis loss in low frequency. With the increase of frequency, eddy current loss increased drastically compared with the hysteresis loss, the eddy current loss was greater than the hysteresis loss when the frequency was higher than 5 kHz and 6 kHz for amorphous alloy with the composition of Fe78Si9B13 and Fe80Si9B11, respectively. The eddy current loss proportion in total loss increased with the increment of frequency.

scholarly journals Circuits and architectures for high frequency synthesizer in CMOS

2021 ◽  
Author(s):  
Nawreen Rashid Khan
Keyword(s):  
High Frequency ◽  
Power Efficiency ◽  
Delay Line ◽  
Pulse Generator ◽  
Frequency Synthesizer ◽  
Total Power ◽  
60 Ghz ◽  
Frequency Range ◽  
Frequency Tracking ◽  
Locking Range

This thesis proposes a novel architecture for high frequency synthesizer design focusing mainly on the 60 GHz frequency range. It consists of a PLL cascaded to an ILO. In order to generate narrow pulses and to relax the multiplication ration of the ILO, a DLL with a pulse generator is used. Passive delay line stacked on top of LC VCO is used for power efficiency and replica-biasing technique of frequency tracking is used for increasing the locking range of ILO. The synthesizer operates at 50 GHz with a phase noise of -98, -117 and -128 dBc/Hz at 1 MHz, 10 MHz and 40 MHz respectively. The total power consumed by the frequency synthesizer from 1.2 V supply is 57 mW. To have channel selection capability, fractional PLL may be used. A novel fractional PLL architecture is also proposed which de-couples the residual jitter from the PLL bandwidth.

scholarly journals Circuits and architectures for high frequency synthesizer in CMOS

2021 ◽  
Author(s):  
Nawreen Rashid Khan
Keyword(s):  
High Frequency ◽  
Power Efficiency ◽  
Delay Line ◽  
Pulse Generator ◽  
Frequency Synthesizer ◽  
Total Power ◽  
60 Ghz ◽  
Frequency Range ◽  
Frequency Tracking ◽  
Locking Range

This thesis proposes a novel architecture for high frequency synthesizer design focusing mainly on the 60 GHz frequency range. It consists of a PLL cascaded to an ILO. In order to generate narrow pulses and to relax the multiplication ration of the ILO, a DLL with a pulse generator is used. Passive delay line stacked on top of LC VCO is used for power efficiency and replica-biasing technique of frequency tracking is used for increasing the locking range of ILO. The synthesizer operates at 50 GHz with a phase noise of -98, -117 and -128 dBc/Hz at 1 MHz, 10 MHz and 40 MHz respectively. The total power consumed by the frequency synthesizer from 1.2 V supply is 57 mW. To have channel selection capability, fractional PLL may be used. A novel fractional PLL architecture is also proposed which de-couples the residual jitter from the PLL bandwidth.

Reliability of the Minimum Masking Level as Outcome Variable in Tinnitus Clinical Research

2020 ◽  
Vol 29 (3) ◽  
pp. 429-435
Author(s):  
Patricia C. Mancini ◽  
Richard S. Tyler ◽  
Hyung Jin Jun ◽  
Tang-Chuan Wang ◽  
Helena Ji ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Frequency ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Outcome Variable ◽  
Reliable Estimate ◽  
Moderate Correlation ◽  
Trained Subjects ◽  
The Relationship ◽  
Minimum Intensity

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2–3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation ( r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Comparison of In-the-Ear and Over-the-Ear Hearing Aid Fittings

1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Comparative Evaluation ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Aid Fitting ◽  
The Difference ◽  
Functional Gain ◽  
The Relationship

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.

HIGH FREQUENCY OHMIC LOSSES IN TERAHERTZ FREQUENCY RANGE CW KLYNOTRONS

2017 ◽  
Vol 76 (10) ◽  
pp. 929-940 ◽  
Author(s):  
Yu. S. Kovshov ◽  
S. S. Ponomarenko ◽  
S. A. Kishko ◽  
A. A. Likhachev ◽  
S. A. Vlasenko ◽  
...  
Keyword(s):  
High Frequency ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Ohmic Losses
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