• Title/Summary/Keyword: resonance energy

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Models and Experiments for the Main Topologies of MRC-WPT Systems

  • Yang, Mingbo;Wang, Peng;Guan, Yanzhi;Yang, Zhenfeng
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1694-1706
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    • 2017
  • Models and experiments for magnetic resonance coupling wireless power transmission (MRC-WPT) topologies such as the chain topology and branch topology are studied in this paper. Coupling mode theory based energy resonance models are built for the two topologies. Complete energy resonance models including input items, loss coefficients, and coupling coefficients are built for the two topologies. The storage and the oscillation model of the resonant energy are built in the time domain. The effect of the excitation item, loss item, and coupling coefficients on MRC systems are provided in detail. By solving the energy oscillation time domain model, distance enhancing models are established for the chain topology, and energy relocating models are established for the branch topology. Under the assumption that there are no couplings between every other coil or between loads, the maximum transmission capacity conditions are found for the chain topology, and energy distribution models are established for the branch topology. A MRC-WPT experiment was carried out for the verification of the above model. The maximum transmission distance enhancement condition for the chain topology, and the energy allocation model for the branch topology were verified by experiments.

Triplet Excitation Energy Transfer in Choleic Acid Crystals

  • Kook, Seong-Keun
    • Bulletin of the Korean Chemical Society
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    • v.28 no.12
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    • pp.2409-2413
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    • 2007
  • Time resolved phosphorescence of Dibromobenzophenone (DBBP) choleic acid crystal was observed at 4.2 K as functions of excitation energy and delay time. The experimental results reveal that the energy transfer efficiency is dependent on the excitation energy, i.e. the density of acceptors sites. As the excitation energy or delay time increases, the resonance phosphorescence does not broaden and shift gradually, rather a broad luminescence band develops about 290 cm?1 to lower energy of the resonance phosphorescence. The observation implies that energy transfer from high to low energy sites in this system is controlled by emission of phonons or vibrons. The data of time resolved experiments were analyzed in terms of a mechanism involving direct donor-acceptor excitation transport by exchange coupling. It was concluded that an isotropic twodimensional exchange interaction topology is consistent with energy transfer in this system.

The Comparative Study on the Characteristics of Thermoacoustic Laser According to Shapes of Resonance Tube (공명 튜브의 기하학적 형상에 따른 열음향 레이저의 특성 비교 연구)

  • Kim, Nam-Jin;An, Eoung-Jin;Oh, Won-Jong;Oh, Seung-Jin;Chun, Wongee
    • Journal of Energy Engineering
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    • v.21 no.2
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    • pp.133-137
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    • 2012
  • Among various clean energy technologies, the solar energy technology has been widely used in various fields such as photovoltaic power generation and solar water/space heating. These days, special attention is drawn on its conversion into acoustic energy along with waste heat as a means to promote clean energy utilization. This work was carried out to investigate the possibility of converting solar energy into acoustic waves, especially, its performance characteristics for a single resonance tube (20.2 mm in ID). Variations are made for the stack length and its position as well as power supply. For a resonance tube of 200mm, an average sound pressure of 114.5 dB was measured with a stack length of 25.6mm at 5cm from the closed end. When the power supply was increased to 35W, an average sound pressure of 117.29 dB was detected with a frequency of 500Hz. There was an increase in frequency, 630 Hz (115.7dB), with a shorter resonance tube of 150mm.

CdS Nanoparticles as Efficient Fluorescence Resonance Energy Transfer Donors for Various Organic Dyes in an Aqueous Solution

  • Ock, Kwang-Su;Ganbold, Erdene-Ochir;Jeong, Sae-Ro-Mi;Seo, Ji-Hye;Joo, Sang-Woo
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3610-3613
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    • 2011
  • CdS nanoparticles (NPs) were synthesized in an aqueous phase in order to investigate their spectral behaviors as efficient fluorescence resonance energy transfer (FRET) donors for various organic dye acceptors. Our prepared CdS NPs exhibiting strong and broad emission spectra between 480-520 nm were able to transfer energy in a wide wavelength region from green to red fluorescence dyes. Rhodamine 6G (Rh6G), rhodamine B (RhB), and sulforhodamine 101 acid (Texas red) were tested as acceptors of the energy transfer from the CdS NPs. The three dyes and synthesized CdS NPs exhibited good FRET behaviors as acceptors and donors, respectively. Energy transfers from the CdS NPs and organic Cy3 dye were compared to the same acceptor Texas red dye at different concentrations. Our prepared CdS NPs appeared to exhibit better FRET behaviors comparable to those of the Cy3 dye. These CdS NPs in an aqueous solution may be efficient FRET donors for various organic dyes in a wide wavelength range between green and red colors.

Analysis of the Effect of Small-Bore Piping Resonance Frequency on Defect of Welding Area (용접부의 결함이 소구경배관의 공진 주파수에 미치는 영향 분석)

  • Yoon, Min Soo;Song, Ki O;Lee, Jae Min;Ha, Seung Woo;Cho, Sun Young
    • Journal of the Korean Society of Safety
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    • v.33 no.5
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    • pp.9-14
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    • 2018
  • The piping system of a nuclear power plant plays a role of transferring high energy fluid to equipment and various devices. The safety and soundness of these piping systems are very closely related to the operability of the power plant. In the case of a welded part of a small diameter pipe, it may grow as a microcrack due to a lack of penetration, and it may grow to a size that affects the safety of the pipe due to the influence of mechanical vibration and fatigue load. Resonance refers to an increase in energy as the natural frequency of an object coincides with the frequency applied to the external force. When this resonance occurs, the frequency is the resonance frequency. In this study, when defects exist in the welds of small diameter pipe, the natural frequency of the pipe changes and resonance may occur. Since these resonances are likely to cause fatigue damage to the piping, resonance frequency changes due to the size and shape of the defects are analyzed and evaluated. As a result of the vibration test, the resonance frequency tended to decrease as the depth of the defect deepened, and the influence was larger when the defect existed at the bottom of the top of the trough. Also, it was confirmed that the Transverse cracks had an effect on the resonance frequency in the presence of the cracks in the weld bead, compared to the longitudinal cracks. As a result of this study, it is expected that the cause of the defect and the condition of the pipe can be monitored because the resonance frequency tendency according to the shape of the crack is analyzed.

Calculation of Energy Dependent Neutron Correction Coefficient Ratios of Natural Rhodium in Energy Region from 0.003 to 100 eV

  • Lee, Sam-Yol
    • Journal of the Korean Society of Radiology
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    • v.2 no.3
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    • pp.33-35
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    • 2008
  • In the neutron capture experiment and calculation, the neutron absorption and scattering are very important. Especially these effects are conspicuous in the resonance energy region and below the thermal energy region. In the present study, we obtained energy dependent neutron absorption ratios of natural rhodium in energy region from 0.003 to 100 eV by MCNP-4B Code. The coefficients for neutron absorption was calculated for several types of thickness. In the lower energy region, neutron absorption is larger than higher region, because of large capture cross section (1/v). Furthermore it seems very different neutron absorption in the large resonance energy region. These results are very useful to decide the thickness of sample and shielding materials.

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NEUTRON INDUCED CROSS SECTION DATA FOR IR-191 AND IR-193

  • Lee, Yong-Deok;Lee, Young-Ouk
    • Nuclear Engineering and Technology
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    • v.38 no.8
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    • pp.803-808
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    • 2006
  • The neutron induced nuclear cross section data for Ir-191 and Ir-193 were calculated and evaluated from unresolved resonance energy to 20MeV. The energy-dependent optical model potential parameters were determined based on the experimental data and applied up to 20MeV. A spherical optical model, a statistical model in an equilibrium energy region, and a multistep direct and multistep compound model in a pre-equilibrium energy region were used in the calculations. The direct capture model enhanced the fast neutron capture in the pre-equilibrium energy. The theoretically calculated cross sections were compared with the experimental data and the evaluated files. The calculations were found to be in good agreement with the experiment data. The evaluated cross section results were compiled with the ENDF-6 format. The fast energy results will be merged with the resonance parts to create a full evaluation library. The improvement of the neutron-induced cross section data will contribute to an increase in the efficiency of the production of Ir-192 as a radiation source.

Pulsed Electron Paramagnetic Resonance Application on the Photoinduced Charge Separation of Alkylphenothiazine Derivatives in Molecular Assemblies

  • Kang, Young-Soo;Park, Chan-Young
    • Journal of the Korean Magnetic Resonance Society
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    • v.4 no.2
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    • pp.82-90
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    • 2000
  • Photoinduced charge separation of alkylphenothiazines in molecular assemblies such as positively, negatively and neutrally charged micelle interface results in the paramagnetic phenothiazine cation radical. This was studied as a model system for the light energy conversion into chemical energy. The photoproduced phenothaizne cation radical was identified and its amount was quantized with electron spin resonance (ESR). The microenvironment of photoproduced cation radical was studied with pulsed-ESR. Such a charge separation is enhanced by the optimization of various structural factors of the molecular assemblies. The structural factors of molecular assemblies have focused on the interface charge, interface structure with different headgroups and interfacial perturbation by disolving interface active organic additives.

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Determination of Alpha Defect Center in the Nature Using EPR Spectroscopy

  • Cho, Young-Hwan;Hyun, Sung-Pil;Pilsoo Hahn
    • Journal of the Korean Magnetic Resonance Society
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    • v.5 no.1
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    • pp.13-18
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    • 2001
  • Natural alpha radiation produced a stable defect center to certain minerals. Electron Paramagnetic Resonance(EPR) spectroscopy is a powerful tool f3r quantifying this defect center. EPR method has been applied to trace alpha-radiation effect around the uranium ore deposit. The results show that EPR technique can be used to measure rapidly and nondestructively the defect center produced by natural alpha radiation. In general, a good correlation was achieved between defect center concentration and actinide elements(U, Th). These results imply that the concentration of defect center is dependent on the alpha radiation dose over long time scale.

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Integrated design method of suction muffler in compressor (압축기 흡입 머플러 통합적 설계 방안)

  • Wang, Semyung;Oh, Seungjae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.771-772
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    • 2014
  • In this paper, the integrated design method of suction muffler in compressor was studied. There are three things to consider when designing this. First, the transmission loss was maximized to consider the noise reduction. Second, dissipation energy of fluid flow was minimized for energy efficiency. Finally, acoustical resonance frequency of suction muffler was controlled because energy efficiency can be increased by supercharging of refrigerant. Therefore, suction muffler was designed to have the specific resonance frequency. The input impedance was used for designing target acoustical resonance frequency. Topology optimization was used for optimization method.

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