Temat: resonance frequency

Skocz do pozycji: 1.

Tytuł:: Multicomponent ceramic materials on the basis of PZT for the production of piezoelectric resonators
Autorzy:: Bochenek, D.
Surowiak, Z.
Gavrilyachenko, S. V.
Kupriyanov, M. F.
Tematy:: PZT
piezoelectric transducers
resonance frequency
thermal stability; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/176898.pdf Link otwiera się w nowym oknie
Opis:: Investigations on the influence of the PbTiO₃ content on the crystalline and domain structure of PZT-based four-component solid solutions have been performed. It has been shown that there is a close relation between the structure and temperature stability of the resonance frequency (f_r) of the fabricated piezoceramic transducers. Better and more stable results have been obtained by doping and modifying the basic chemical composition obtaining Pb(Zr_1-x Ti_x)O₃. The compositions with minimal Δ f_r / f_r, within the temperature range T = 213–358 K (in relation to room temperature T_r = 293 K), exhibited (i) the smallest internal friction (Q^-1_m), (ii) the highest mechanical quality (Q_m), (iii) high values of spontaneous deformation of the elementary cell (δ_T and δ_Re), (iv) the complex a-c-domain structure in the tetragonal phase (T) and the simple domain structure in the rhombohedral phase (Re). The practical result of the present work was the fabrication of piezoceramic electric band filters exhibiting Δ f_r / f_r < 0.2% and a high mechanical quality factor (Q_m = 3225).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Flexoelectric and surface effects on a cracked piezoelectric nanobeam: Analytical resonant frequency response
Autorzy:: Bastanfar, M
Hosseini, S.A.H.
Sourki, R.
Khosravi, F.
Tematy:: flexoelectricity
surface effects
imperfections
resonance frequency
nanobeam; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/140249.pdf Link otwiera się w nowym oknie
Opis:: A nanoscale beam model containing defect under the piezoelectricity considering the surface effects and flexoelectricity is established on the framework of Euler-Bernoulli theory. The governing equations of motion and related boundary conditions are derived by using Hamilton’s principle. The imperfect nanobeam is modeled by dividing the beam into two separate parts that are connected by a rotational and a longitude spring at the defect location. Analytical results on the free vibration response of the imperfect piezoelectric nanobeam exhibit that the flexoelectricity and the surface effects are sensitive to the boundary conditions, defect position, and geometry of the nanobeam. Numerical results are provided to predict the mechanical behavior of a weakened piezoelectric nanobeam considering the flexoelectric and surface effects. It is also revealed that the voltage, defect severity, and piezoelectric material have a critical role on the resonance frequency. The work is envisaged to underline the influence of surface effects and flexoelectricity on the free vibration of a cracked piezoelectric nanobeam for diverse boundary conditions. It should be mentioned, despite our R. Sourkiprevious works, an important class of piezoelectric materials used nowadays and called piezoelectric ceramics is considered in the current study.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Design and Analysis of Circular Slotted Microstrip Patch Antenna
Autorzy:: Bhattacharyya, Kaustubh
Thangjam, Rupanda
Goswami, Sivaranjan
Sarmah, Kumaresh
Baruah, Sunandan
Tematy:: impedance matching
microstrip
resonance frequency
complementary
split ring resonators; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/963802.pdf Link otwiera się w nowym oknie
Opis:: This paper presents a novel complementary CPWfed slotted microstrip patch antenna for operation at 2.4 GHz, 5.2 GHz and 6.3 GHz frequencies. The primary structure consists of the complementary split ring resonator slots on a patch and the design is fabricated on FR-4 epoxy substrate with substrate thickness of 1.6 mm. The described structure lacks the presence of a ground plane and makes use of a number of circular complementary SRRs along with rectangular slots on the radiating patch. The structure provides a wide bandwidth of around 390 MHz, 470 MHz and 600 MHz at the three bands with return losses of -11.5 dB, -24.3996dB and -24.4226 dB, respectively. The inclusion of the rectangular slots in the CSRR based slot antenna with stairecase structure improved the performance with respect to return loss.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Acoustic Estimation of Resonance Frequency and Sonodestruction of SonoVue Microbubbles
Autorzy:: Jurkonis, R.
Lamanauskas, N.
Šatkauskas, S.
Tematy:: SonoVue
microbubble
loss of amplitude
attenuation coefficients
resonance frequency
sonodestruction; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/178018.pdf Link otwiera się w nowym oknie
Opis:: Acoustic properties of ultrasound (US) contrast agent microbubbles (MB) highly influence sonoporation efficiency and intracellular drug and gene delivery. In this study we propose an acoustic method to monitor passive and excited MBs in a real time. MB monitoring system consisted of two separate transducers. The first transducer delivered over an interval of 1 s US pulses (1 MHz, 1% duty cycle, 100 Hz repetition frequency) with stepwise increased peak negative pressure (PNP), while the second one continuously monitored acoustic response of SonoVue MBs. Pulse echo signals were processed according to the substitution method to calculate attenuation coefficient spectra and loss of amplitude. During US exposure at 50–100 kPa PNP we observed a temporal increase in loss of amplitude which coincided with the US delivery. Transient increase in loss of amplitude vanished at higher PNP values. At higher PNP values loss of amplitude decreased during the US exposure indicating MB sonodestruction. Analysis of transient attenuation spectra revealed that attenuation coefficient was maximal at 1.5 MHz frequency which is consistent with resonance frequency of SonoVue MB. The method allows evaluation of the of resonance frequency of MB, onset and kinetics of MB sonodestruction.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: A Clamped Bar Model for the Sompoton Vibrator
Autorzy:: Wong, T. H.
Dayou, J.
Ngu, M. C. D.
Hang, J. H. W.
Liew, W. Z. H.
Tematy:: vibrator
clamped bar
single degree of freedom system
exact analysis
resonance frequency; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/176855.pdf Link otwiera się w nowym oknie
Opis:: The sompoton is one of famous traditional musical instruments in Sabah. This instrument consists of several parts with the vibrator being the most important one. In this paper, the vibrator is modeled as a clamped bar with a uniformly distributed mass. By means of this model, the fundamental frequency is analyzed with the use of an equivalent single degree of freedom system (SDOF) and exact analysis. The vibrator is made of aluminum in different sizes and is excited using a constant air jet to obtain its fundamental resonance frequency. The fundamental frequency obtained from the experimental measurement is compared with the theoretical values calculated based on the equivalent SDOF and exact analysis theories. It is found that the exact analysis gives a closer value to the experimental results as compared to the SDOF system. Although both the experimental and theoretical results exhibit the same trend, they are different in magnitude. To overcome the differences in both theories, a correction factor is added to account for the production errors.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Antenna Design based on Meander Line Technique to be applied to RFID tag
Autorzy:: González, Ricardo Meneses
Peralta, Laura Montes
Tematy:: loop antenna
meander line technique
resonance frequency
parasitic elements
RFID tag antenna; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1190179.pdf Link otwiera się w nowym oknie
Opis:: This work describes the design and implementation of an antenna based on meander line technique and ended in circular structures and two parasitic element acting as reflectors, in order to be applied as 915 MHz UHF RFID tag antenna. In order to determine the performance of varying design parameters on impedance, resonance frequency, radiation pattern, etc., HFSS simulation software has been used and experimental tests under an anechoic chamber have been applied. The achieved results show the feasibility of the designed antenna.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: A semiclassical model for a laser field inside an optical cavity
Autorzy:: Priyashanka, K. M.
Wijewardena Gamalath, K. A. I. L.
Tematy:: Semi classical theory
cavity electric field
population inversion
pump parameter
resonance frequency
threshold population; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1194053.pdf Link otwiera się w nowym oknie
Opis:: Treating the laser medium quantum mechanically and the laser electric field classically, a mathematical model was developed to study a laser field inside a single mode optical cavity by numerical and analytical techniques. The simulations for threshold population, population inversion and average population with electric field frequency for 500 kHz resonance frequency of the atom are presented. The gain coefficient and the pump parameter with the frequency of the cavity electric field for 1000 kHz resonance frequency of the atom were simulated. The threshold population is a minimum when the frequency of electric field is equal to the resonance frequency of the atom. The population inversion varies sinusoidal with time and the frequency of the electric field and is a maximum at the threshold frequency of the atom. The saturated laser intensity at steady state increases linearly with the pump parameter and for larger values of the pump parameter, a smaller time is needed to reach the saturation of the laser field.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Application of numerical analysis in dynamic state diagnosis of the machine with a shock character of operation
Analiza numeryczna w diagnozowaniu stanu dynamicznego maszyn o udarowym charakterze pracy
Autorzy:: Zachwieja, J.
Tematy:: model numeryczny
diagnozowanie
częstotliwość rezonansowa
drgania konstrukcji
wibroizolacja
numerical methods
diagnostics
resonance frequency
structure vibrations
vibration isolation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Powiązania:: https://bibliotekanauki.pl/articles/329414.pdf Link otwiera się w nowym oknie
Opis:: Numerical analysis is a basic tool for the engineer. Over the years many methods have been developed which turned out to be more or less universal in applications. In the approach to the problem of machine vibration damping based on the machine model, many approximate calculation methods must be used or combined so as to benefit from their advantages and eliminate possible weak points. The hybrid method, developed as a combination of a deformable finite elements method and the dynamics of multi-link systems, was used in the study as one of the tools for vibrating screen's dynamic state diagnostic. The exemplary application of numerical modelling to the issue of multidirectional optimization of an effective machine vibration isolation at the design stage is presented.
Analiza numeryczna stanowi podstawowe narzędzie inżyniera. Na przestrzeni lat powstało wiele metod, które okazały się w zastosowaniach mniej lub bardziej uniwersalne. Podejście do zagadnienie tłumienia drgań maszyny w oparciu o jej model wymaga stosowania wielu metod obliczeń przybliżonych lub ich łączenia w sposób umożliwiający wykorzystanie zalet każdej z nich oraz wyeliminowanie ewentualnych wad. Metoda hybrydowa powstała z połączenia metody odkształcalnych elementów skończonych i dynamiki układów wieloczłonowych została wykorzystana w pracy jako jedno z narzędzi diagnozowania stanu dynamicznego przesiewacza wibracyjnego. Pokazany został przykład zastosowania modelowania numerycznego do zagadnienie wielokierunkowej optymalizacji przy opracowaniu skutecznej wibroizolacji maszyny.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Предупреждение осложнений имплантации на этапе первичной фиксации имплантата
Prevention of complications of implantation at primary implant fixation
Autorzy:: Vakulenko, V.I.
Goncharenko, E.V.
Schneider, S.A.
Kovshar, I.P.
Tematy:: ортопантомография
конусно-лучевая компьютерная томография
частотнорезонансный анализ.
ортопантомографія
конусно-променева комп'ютерна томографія
частотнорезонансний аналіз.
orthopantomography
cone-beam computer tomography
resonance-frequency analysis; Pokaż więcej
Wydawca:: Uniwersytet Kazimierza Wielkiego w Bydgoszczy
Powiązania:: https://bibliotekanauki.pl/articles/1032533.pdf Link otwiera się w nowym oknie
Opis:: Статья посвящена оптимизации планирования имплантации с целью снижения осложнений на этапе первичной фиксации имплантата. Сравнивались такие методики диагностики в имплантологии, как ортопантомография и конусно-лучевая компьютерная томография. Для определения механической стабильности имплантата использовался частотно-резонансный анализ.
The article is devoted to optimization of implant planning in order to reduce complications in primary fixation of the implant. Such diagnostic techniques in implantology as orthopantomography and cone-beam computed tomography were compared. The resonancefrequency analysis was used to determine the mechanical stability of the implant.
Стаття присвячена оптимізації планування імплантації з метою зниження ускладнень на етапі первинної фіксації імплантату. Порівнювалися такі методики діагностики в імплантології, як ортопантомографія і конусно-променева комп'ютерна томографія. Для визначення механічної стабільності імплантату використовувався частотно-резонансний аналіз.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Preparation and Characterization of a Novel Coordination Compound [K(18-crown-6)][N(NO2)2]
Autorzy:: Lu, Zhimeng
Ren, Xiaoting
He, Jinxuan
Tematy:: low-frequency resonance technology
[K(18C6)][N(NO2)2]
coordination compound structure; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/27788036.pdf Link otwiera się w nowym oknie
Opis:: Low-frequency resonance technology is a promising technology for mixing or manufacturing energetic materials, and has been a hot topic in the field of material preparation. In this paper, we describe the first use of low-frequency resonance technology for the synthesis of new compounds and for performing innovative research. The coordination compound, [K(18-crown-6)][N(NO2)2] ([K(18C6)][N(NO2)2]), was first prepared by using a conventional slow solvent evaporation method over 10 days. The crystal structure of this compound was characterized by single crystal X-ray diffraction (SXD) and revealed that [K(18C6)][N(NO2)2] belongs to the monoclinic system, in which the space group is P21/c. The main intermolecular interactions in [K(18C6)][N(NO2)2] are the K–O coordination bonds and C–H...O hydrogen bonds. The crystallographic parameters are a = 8.5032(2) Å, b = 14.4060(4) Å, c = 8.1708(2) Å, β = 101.896(2), V = 979.40(4) Å3, Z = 2, ρ = 1.388 g·cm–3. The coordination compound [K(18C6)][N(NO2)2] was then prepared by low-frequency resonance technology in only 65 min. The results of X-ray powder diffraction (PXRD), differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR) showed that low-frequency resonance technology can successfully and efficiently prepare [K(18C6)] [N(NO2)2]. Compared to potassium dinitramide (KDN), [K(18C6)][N(NO2)2] has unique characteristics.
Dostawca treści:: Biblioteka Nauki

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