• Journal of the Korean Magnetic Resonance Society
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• v.3 no.2
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• pp.140-148
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• 1999

Using 1H magnetic resonance spectroscopy (MRS), we quantitatively evaluated correlation representing linear relationship between the metabolite peak area ratios associated with poor shimming conditions. The inadequate shimming due to linear shim offsets directly affected overall MR spectral quality as well as peak area for each metabolite. Three major peaks such as N-acetylaspartate (NAA), creatine (Cr,) choline (Cho) were used as a reference for data analysis. Despite considerable variations of metabolite peak area, a significant correlation between the metabolite peak area ratios relative to Cr was established while the correlation between the peak area ratios relative to Cho and NAA was not. The present study suggested that metabolite peak area ratios based on the metabolite of Cr could be an acceptable quantification method even under the poor shimming in clinical MRS examination.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.235-239
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• 2018

Due to the structure with one end closed, the external ear resonance effect in which the high frequency is amplified can be generated, and the sound can be perceived well. The external ear resonance normally has a first peak and a second peak. On average, the first peak has a gain of 18.6 dB at 2620 Hz and the second peak has a gain of 18.2 dB at 4210 Hz. The resonance of the external auditory canal changes with the state of the tympanic membrane, the presence of the ventilation tube, and the structure (length, diameter, shape) of the external auditory canal. A patient with a postauricular meatomastoid cutaneous fistula was admitted to the hospital with a foreign body which is the molding of the hearing aid. After removal of the foreign body, the resonance of the external auditory canal was lost and the subjective sound cognitive ability decreased. In the case of postauricular meatomastoid cutaneous fistula, we confirmed the improvement of sound cognitive ability, the change of pure tone hearing threshold, and the change of the external ear resonance after reconstruction of the ear canal without middle ear reconstruction.

• Investigative Magnetic Resonance Imaging
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• v.7 no.1
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• pp.31-38
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• 2003

Purpose : To analyze the serial changes of proton magnetic resonance (MR) spectra in the abscess and to determine the effect of the antibiotic treatment on the metabolite patterns. Materials and Methods : MR imaging and MR spectroscopy of an experimentally induced abscess were performed sequentially for four weeks at interval of one week in both the control group (n=5) and the antibiotic treatment group (n=5). On MR imaging, the shape and the size of the abscess were analyzed. On MR spectroscopy, the resonance peaks of metabolites were assigned on the basis of reported peaks in the literature. The metabolite ratios measured by using N-acetyl alanine as an external reference and by using lipid as an internal reference were compared in both the control and treatment g roups. Results : The abscesses were seen as cystic masses on MR imaging. On MR spectroscopy, the variable peaks of acetate, succinate and various amino acids, which are the metabolites of infection, were identified in the control and antibiotic treatment groups. The most frequent peak was that of acetate at 1.92ppm (70%). Both the peak ratios of acetate to lipid and acetate to external reference tended to decrease in the treatment group while the ratios did not change significantly in the control group. Conclusion : MR spectroscopy is useful not only for the diagnosis of abscess but also for monitoring the evolution of the abscess by using the acetate peak.

• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.326-333
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• 2013

On $H^1$ MRS (magnetic resonance spectroscopy), malignant tumors show higher concentration of metabolite than benign lesions. Lactate double peak was detected in malignant tumor and endometriosis, and more prominent high concentration was demonstrated in endometriosis. Tuboovarian abscesses and salpingitis do not show prominent peak. Dermoid cysts show high levels of lipid peak. Paratubal cyst and follicular cyst can be showed the lipid peak, however, the concentration of lipid is lower than that of dermoid cyst. $H^1$ MRS of ovarian cystic lesions can give valuable information about the presence of metabolites of ovarian cystic lesions.

• Journal of the Korean Magnetic Resonance Society
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• v.7 no.2
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• pp.74-79
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• 2003

Li[Ni,Mn,Co]O$_2$ electrode has been studied by $\^$7/Li MAS NMR. A sharp resonance at -1 ppm and a very broad resonance at approximately 400 ppm are assigned to the Li ions in Co-only environment and Ni/Mn(Co) environment, respectively, indicating a segragation of Co ions and Ni/Mn ions. Different temperature behavior of the peak position is observed for Co-only environment and Ni/Mn(Co) environment. Oxidation of Ni ions is involved during the entire charging process. At high temperature, a peak narrowing caused by the electron hopping is observed.

• Korean Journal of Optics and Photonics
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• v.33 no.4
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• pp.177-186
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• 2022

The performance of a surface plasmon resonance sensor is evaluated based on the sensitivity (nm/RIU) and sharpness from the full width at half maximum (FWHM) and the peak depth of a resonance peak. These factors are determined by the materials and conformational properties of the sensing structure. In this paper, we investigated an optimized insulator-metal-insulator (IMI) multilayer-based surface plasmon resonance sensor structure to simultaneously achieve high sensitivity, narrow FWHM, and deep peak depth while using gold for the metallic film layer which occurs peak broadening. By adopting the optimized structure, sensitivity of 8,390 nm/RIU, FWHM of 11.92 nm, and a resonance peak depth of 93.1% were achieved for 1.45-1.46 refractive index variation of the sensing layer. With the suggested structure conformation, high sensitivity and resolution of sensing performance can be achieved.

• Journal of Magnetics
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• v.17 no.4
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• pp.245-250
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• 2012

Ferromagnetic resonance and X-ray specular reflectivity measurements were performed on $Ni_{81}Fe_{19}/Ir_{20}Mn_{80}/Co_{90}Fe_{10}$ exchange bias trilayers, which were grown using the pulsed-DC magnetron sputtering technique on Si(100)/$SiO_2$(1000 nm) substrates, to investigate the evolution of the interface roughness and exchange bias and their dependence on the NiFe layer thickness. The interface roughness values of the samples decrease with increasing NiFe thickness. The in-plane ferromagnetic resonance measurements indicate that the exchange bias field and the peak-to-peak line widths of the resonance curves are inversely proportional to the NiFe thickness. Furthermore, both the exchange bias field and the interface roughness show almost the same dependence on the NiFe layer thickness. The out-of plane angular dependent measurements indicate that the exchange bias arises predominantly from a variation of exchange anisotropy due to changes in interfacial structure. The correlation between the exchange bias and the interface roughness is discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.129-133
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• 2005

Vibration transmitted through rolling tire is a major source of road noise in vehicle interior noise on the range of low frequency.($0{\sim}500Hz$) Among various road noises, tire cavity noise has very peak on $200{\sim}250Hz$. And generally it is generated by cavity resonance of tire. In this paper, tire cut-sample is used to calculate the tire cavity frequency. Cavity resonance frequency of tire is measured through vertical/tangential forces at load cell of axle using drum cleat impact. This method is useful to find cavity peak because measured forces do not have complex peaks. And changing the test conditions (air inflation, loads), tire cavity resonance characteristics are identified. Finally, vehicle interior noise is measured as tire/vehicle are changing. As difference of tire vertical force is bigger, interior noise level is higher at cavity frequency. Also we can assume that vehicle sensitivity is important factor at tire cavity noise.

• Current Optics and Photonics
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• v.7 no.1
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• pp.47-53
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• 2023

We propose a centralized passive-optical-network monitoring scheme using the resonance-spectrum properties of a Fabry-Perot cavity based on fiber Bragg gratings. Each cavity consists of two identical uniform fiber Bragg gratings and a varying cavity length or grating length, which can produce a unique single-mode resonance spectrum for the drop-fiber link. The output spectral properties of each cavity can be easily adjusted by the cavity length or the grating length. The resonance spectrum for each cavity is calculated by the transfer-matrix method. To obtain the peak wavelength of the resonance spectrum more accurately, the effective cavity length is introduced. Each drop fiber with a specific resonance spectrum distinguishes between the peak wavelength or linewidth. We also investigate parameters such as reflectivity and bandwidth, which determine the basic performance of the fiber Bragg grating used, and thus the output-spectrum properties of the Fabry-Perot cavity. The feasibility of the proposed scheme is verified using the Optisystem software for a simplified 1 × 8 passive optical network. The proposed scheme provides a simple, effective solution for passive-optical-network monitoring, especially for a high-density network with small end-user distance difference.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.477-480
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• 2004

We studied the characteristics of impedance and electromechanical coupling coefficient in ZnO and AIN thin films by using resonance frequency spectrum method. The response peak of impedance decreased with the decrease of thickness of piezoelectrics, the number of mode of response peak increased with the increase of substrate thickness. An error of $k_{t}^{2}$ estimated from input $k_{t}^{2}$ increased as the thickness of piezoelectrics decreased and the thickness of substrate increased. Also, the error was increased in case of a large acoustic impedance of substrate. It was found that the composite resonator operating in optimized condition could be designed through the resonance frequency spectrum analysis of composited resonator consisted of piezoelectric thin film and substrate.