• 제목/요약/키워드: Resonance peak

검색결과 446건 처리시간 0.027초

Correlation between Metabolite Peak Area Ratios on the Influence of Poor Shimming by $^1H$ MR Spectroscopy

  • Baik, Hyun-Man;Choe, Bo-Young;Suh, Tae-Suk;Lee, Hyuong-Koo
    • 한국자기공명학회논문지
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    • 제3권2호
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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.

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외이도-유양동-귀뒤바퀴피부 누공환자에서 수술 전, 후의 외이도 공명의 변화 (The Changes of External Ear Resonance after Surgery for Repair of the Postauricular Meato-Mastoid Cutaneous Fistula)

  • 김상준;강명구;정성욱;이동근
    • 임상이비인후과
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    • 제29권2호
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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.

토끼 대퇴부에 유발한 농양의 생체내 수소 자기공명분광법: 치료효과 평가 (In-vivo $^1H$ MR Spectroscopy in Abscessess Induced in Rabbit Thighs: Evaluation of Treatment Effect)

  • 구진모;장기현;이경호;한문희;송인찬
    • Investigative Magnetic Resonance Imaging
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    • 제7권1호
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    • pp.31-38
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    • 2003
  • 목적 : 실험적으로 토끼 대퇴부에 유발한 농양에서 연속적 추적검사를 통하여 MRS 스펙트럼의 특징과 항생제 치료에 따른 대사산물의 변화를 분석하고자 하였다. 대상 및 방법 : 토끼 10마리의 대퇴부에 흰쥐의 대변으로부터 추출한 용액을 주사하여서 농양을 유발시켰고, 대조군 5마리와 항생제 치료군 5마리로 나누어 4주 동안 1주 간격으로 MRI와 MRS로 추적 검사를 하였다 MRI에서는 농양의 모양과 크기를 분석하였으며, 기존 문헌을 참조하여 MRS에서 보이는 대사산물의 스펙트럼을 분류하였다. N-acetyl alanine을 외적기준으로, lipid를 내적기준으로 하여 각 대사산물을 정량 분석하였고, 정량화된 값들이 농양의 시기에 따라 대조군과 치료군 사이에 차이가 있는지를 분석하였다. 결과 : MRI에서 농양 10 예 모두는 낭성 종괴로 보였으며, 크기는 22-77 mm였다. MRS에서는 감염을 시사하는 acetate, succinate와 여러 종류의 아미노산 peak가 대조군, 치료군 모두에서 여러 가지 조합으로 검출되었다. 그 중 1.92 ppm의 acetate(70%)가 가장 흔하게 보였다. Lipid peak에 대한 acetate peak 비율과 외적기준의 peak에 대한 acetate peak 비율은 대조군에서는 시기에 따라 큰 변화가 없는 반면에 치료군에서는 감소하는 경향이 있었다. 결론 : MRS는 농양에서 감염을 시사하는 대사산물을 검출함으로써 진단에 도움을 줄 수 있을 뿐 아니라 acetate peak는 농양의 진행 및 항생제 치료에 의해 영향을 받아서 농양의 활동도 지표로서 유용한 가치가 있을 것으로 사료된다.

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낭성 난소병변의 자기공명분광술 ($H^1$ Magnetic Resonance Spectroscopy of Cystic Ovarian Lesions)

  • 강영혜;김미영;김경태;김윤정;서창해;김준미;황성욱;박성혁;조재영
    • Investigative Magnetic Resonance Imaging
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    • 제17권4호
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    • pp.326-333
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    • 2013
  • $H^1$ 자기공명분광술에서 악성 종양은 양성 병변보다 더 높은 농도의 대사물질들을 보여준다. 락테이트의 이중 첨단점은 악성 종양과 자궁내막증에서 나타났으며, 자궁내막증에서 더 높은 농도를 보였다. 자궁관난소농양과 난관염은 분명한 첨단점이 보이지 않는다. 유피낭종은 높은 수준의 지질 첨단점이 나타난다. 부난관 낭종 및 난포낭도 지질 첨단점을 보일 수 있지만, 지질의 농도는 유피낭종보다 현저히 낮다. $H^1$ 자기공명분광술은 낭성 난소병변의 대사 물 성분에 대한 유용한 정보를 제공할 수 있다.

Solid NMR Studies of Cathode Materials for Rechargeable Li Battery

  • Lee, Young-Joo;Chun, Kyung-Min;Park, Hong-Kyu
    • 한국자기공명학회논문지
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    • 제7권2호
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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.

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생물학적 분석용 IMI 하이브리드 다중레이어 구조 기반 성능 향상된 표면 플라즈몬 공명 센서의 설계 및 특성 분석 (Design and Evaluation of IMI Multilayer Hybrid Structure-based Performance Enhanced Surface Plasmon Resonance Sensor for Biological Analysis)

  • 송혜린;안희상;김규정
    • 한국광학회지
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    • 제33권4호
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    • pp.177-186
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    • 2022
  • 표면 플라즈몬 공명 센서에서 센서의 성능은 민감도(nm/RIU)와 분해능인 공명 픽의 형태에 의해서 결정된다. 이러한 특성은 센서에 활용되는 구조체의 물질과 구조적 특성에 따라 달라진다. 본 연구에서는 insulator-metal-insulator (IMI) 다중 층 구조를 기반으로 한 표면 플라즈몬 공명 센서 구조의 최적화 과정을 통해 센싱 레이어의 굴절률 변화에 대한 높은 민감도 달성과 동시에 좁은 full width at half maximum (FWHM)과 픽의 깊이 이 두 가지의 요소를 기반으로 한 분해능이 큰 공명 픽을 형성하도록 하는 구조를 찾았다. 이 구조를 통해 센싱 레이어의 굴절률이 1.45-1.46 범위에서 변화할 때 FWHM = 11.92 nm, 픽 깊이 93.1%의 공명 픽이 형성되었고 최대 8,390 nm/RIU의 민감도 성능을 확인했다. 특히 금 박막을 활용한 파장 기반의 표면 플라즈몬 센서는 공명 픽의 너비 확장이 발생하나 금 박막을 사용하고도 좁은 FWHM을 달성함에 의의가 있다. 본 연구에서 제안하는 다중 층 설계를 기반으로 한 센서는 미세한 굴절률 변화 값에 대한 높은 민감도와 더불어 높은 분해능을 가지는 파장 기반 표면 플라즈몬 센서로 활용 가능하다.

Ferromagnetic Resonance and X-Ray Reflectivity Studies of Pulsed DC Magnetron Sputtered NiFe/IrMn/CoFe Exchange Bias

  • Oksuzoglu, Ramis Mustafa;Akman, Ozlem;Yildirim, Mustafa;Aktas, Bekir
    • Journal of Magnetics
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    • 제17권4호
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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.

타이어 공동의 공명에 의한 차량 실내음 전달경로 연구 (Study on Interior Noise Transfer Path Analysis by Tire Cavity Resonance)

  • 이상주;강현석
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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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.

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Uniform-fiber-Bragg-grating-based Fabry-Perot Cavity for Passive-optical-network Fault Monitoring

  • Xuan, Zhang;Ning, Ning;Tianfeng, Yang
    • Current Optics and Photonics
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    • 제7권1호
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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.

공진주파수 스펙트럼법을 이용한 압전박막의 특성 평가 (Evaluating Piezoelectric Thin Film Characteristics Using Resonance Spectrum Method)

  • 최준영;장동훈;강성준;윤영섭
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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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.

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