scholarly journals Гибридный металлополимер как потенциальная активная среда оптоакустического генератора

2022 ◽  
Vol 48 (3) ◽  
pp. 36
Author(s):  
Е.И. Гиршова ◽  
Е.П. Микитчук ◽  
А.В. Белоновский ◽  
К.М. Морозов
Keyword(s):  
Silver Nanoparticles ◽  
Active Medium ◽  
Hybrid Material ◽  
Volume Fraction ◽  
Silver Content ◽  
Thermodynamic Characteristics ◽  
Operating Frequency ◽  
Frequency Range ◽  
Volume Fractions ◽  
Operating Frequency Range

A hybrid material was studied, consisting of polydimethylsiloxane and silver nanoparticles distributed throughout its volume, its optical and thermodynamic characteristics were calculated for different volume fractions of silver content. It is theoretically shown that this material with a volume fraction of silver of about 30% can be used as an active medium for an optoacoustic transducer with an operating frequency range of about 10 MHz.

Extracting Maximum Power in the Presence of Internal Inductance of Electromagnetic Energy Harvesting Systems

2020 ◽  
Author(s):  
Yamini Sharma ◽  
Lei Zuo
Keyword(s):  
Energy Harvesting ◽  
Electromagnetic Energy ◽  
Maximum Power ◽  
Operating Frequency ◽  
Frequency Range ◽  
Low Frequencies ◽  
Internal Inductance ◽  
Piezoelectric Energy ◽  
Operating Frequency Range ◽  
Electromagnetic Energy Harvesting

Abstract In this paper, the effect of internal inductance of electromagnetic generators in the field of energy harvesting is discussed. Electromagnetic energy harvesters are typically operated at low frequencies. This results in the generator internal inductor impedance being significantly less than the generator internal resistance. However, at high frequencies, this inductance can no longer be ignored. Therefore, to maximize the harvested power, the internal inductance must be considered while designing the power electronics. This paper presents two methods to tackle this issue. The first method involves making use of a discrete capacitor which is able to reduce the inductance effect not just at resonant frequency but for the entire operating frequency range. The second method makes use of a concept similar to synchronized switching harvesting on inductors (SSHI) in piezoelectric energy harvesting. A capacitor and switch are added in the electromagnetic energy harvesting circuit to reduce the generator internal inductance effect. This method not only provides the benefit of performing well in the entire operating frequency range but also eliminates the need for precise maximum power tracking techniques, which further helps in reducing the circuit losses. Simulation results show a maximum power output increase of 56%.

PERFORMANCE ANALYSIS OF AN ENGINE MOUNT FEATURING ER FLUIDS AND PIEZOACTUATORS

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3143-3157 ◽  
Author(s):  
S.H. CHOI ◽  
Y.T. CHOI ◽  
S.B. CHOI ◽  
C.C. CHEONG
Keyword(s):  
Electric Field ◽  
Frequency Domain ◽  
Control Technique ◽  
Operating Frequency ◽  
Frequency Range ◽  
Engine Mounts ◽  
Operating Frequency Range ◽  
Engine Mount ◽  
Er Fluids ◽  
Er Fluid

Conventional rubber mounts and various types of passive or semi-active hydraulic engine mounts for a passenger vehicle have their own functional aims on the limited frequency band in the broad engine operating frequency range. In order to achieve high system performance over all frequency ranges of the engine operation, a new type of engine mount featuring electro-rheological(ER) fluids and piezoactuators is proposed in this study. A mathematical model of the proposed engine mount is derived using the bond graph method which is inherently adequate to model the interconnected hydromechanical system. In the low frequency domain, the ER fluid is activated upon imposing an electric field for vibration isolation while the piezoactuator is activated in the high frequency domain. A neuro-control algorithm is utilized to determine control electric field for the ER fluid, and H∞ control technique is adopted for the piezoactuator Comparative works between the proposed and single-actuating(ER fluid only or piezoactuator only) engine mounts are undertaken by evaluating force transmissibility over a wide operating frequency range.

scholarly journals Influence of water content of expanded clay on the reflection coefficient of electromagnetic shild

2021 ◽  
Vol 66 (1) ◽  
pp. 93-100
Author(s):  
T. V. Borbot’ko ◽  
S. E. Savanovich
Keyword(s):  
Reflection Coefficient ◽  
Moisture Content ◽  
Electromagnetic Radiation ◽  
Pore Size ◽  
Operating Frequency ◽  
Reflection Coefficients ◽  
Frequency Range ◽  
Operating Frequency Range ◽  
Influence Of Water ◽  
The Relationship

The regularities of the influence of the moisture content of expanded clay on the values of the reflection coefficient of electromagnetic radiation (EMR) of this material in the frequency range of 1–17 GHz have been established. The relationship between the size of fractions (pore size) of expanded clay and the operating frequency range of the EMR screen samples has been determined. It is shown that a twofold increase in the moisture content of expanded clay with fractions of 1…4 and 10…20 mm provides an extension of the operating frequency range of the EMR shield samples made on the basis of this material, with a decrease in the reflection coefficient of the test samples by 1.7 and 3 times, respectively. It was found that an increase in the moisture content of expanded clay from 19 to 40 % with a decrease in the size of its fractions from 10…20 to 1…4 mm and a pore size from 0.1…0.2 to 0.01…0.06 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 7.7–17.0 GHz, and an increase in the size of expanded clay fractions from 1…4 to 10…20 mm with an increase in the size of its pores from 0.01…0.06 to 0.1…0.2 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 1.0–7.7 GHz. It is shown that the practical use of these regularities makes it possible to form EMR screen samples with reflection coefficients from –2.8 to –22.0 dB in the frequency range 1–17 GHz, which makes it possible to recommend them for use when creating shielded rooms.

scholarly journals Design and Validation of an Antipodal Vivaldi Antenna with Additional Slots

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Marek Dvorsky ◽  
Harihara S. Ganesh ◽  
S. Sadhish Prabhu
Keyword(s):  
Linear Polarization ◽  
Dielectric Substrate ◽  
Substrate Material ◽  
Radiation Efficiency ◽  
Operating Frequency ◽  
Frequency Range ◽  
High Radiation ◽  
Maximum Gain ◽  
Operating Frequency Range ◽  
Vivaldi Antenna

This paper introduces an improved shape of Antipodal Vivaldi Antenna from the normal schematic structure which yields a high radiation gain. We have designed and fabricated the improved structure of Antipodal Vivaldi Antenna with the help of new dielectric substrate ASTRA®MT77 material. We have chosen a unique substrate material to develop our novel Antipodal Vivaldi Antenna because most research has been done on commonly used materials like FR4, RT Duroid, etc. Moreover, ISOLA has significantly good electrical and nonelectrical properties as compared with other substrate materials. The results of the desired antenna were simulated through extensive simulations performed in CST Microwave Studio®. The characteristics of all the antenna parameters are clearly studied and we are successful to achieve closed results between designed as well as experimented Vivaldi Antenna. The simulated antenna achieved a maximum gain of more than 9 dBi whereas the experimental antenna reached around 7 dBi between the operating frequency range from 1 GHz to 13 GHz. The measured prototype antenna provides linear polarization with overall radiation efficiency of more than 90%.

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