• 제목/요약/키워드: Electromagnetic tomography

검색결과 55건 처리시간 0.027초

Overview of Various Measurement Tools for Shoulder Kinematics

  • Kim, Doo Sup;On, Myoung Gi;Yeom, Jun Seop
    • Clinics in Shoulder and Elbow
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    • 제20권4호
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    • pp.244-249
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    • 2017
  • Shoulder kinematics is important, as it is associated with shoulder arthropathy and pain mechanisms. Various static and dynamic analysis methods are prevalent for shoulder kinematics. These include 2-dimensional plane x-ray, computed tomography, and magnetic resonance imaging, cadaver study, electromagnetic motion analysis, transcortical bone pins technique, and in vivo 3-dimensional motion analysis. Although these methods provide the value of the shoulder kinematics angle, they are unable to explain why such changes occur. Since each method has its pros and cons, it is important to understand all factors accurately, and to choose a method that best meets the purpose of the researcher.

Development of Korean Male Body Model for Computational Dosimetry

  • Lee, Ae-Kyoung;Choi, Woo-Young;Chung, Min-Suk;Choi, Hyung-Do;Choi, Jae-Ick
    • ETRI Journal
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    • 제28권1호
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    • pp.107-110
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    • 2006
  • The dimensions of the human body vary by age, sex, and race. The internal structure and outer dimensions of a body exposed to an electromagnetic field is important for accurate dosimetry. The average physical size of Korean adult males between the ages 18 to 24 was investigated, and a male volunteer was selected whose physical condition is within the physical standards, ${\pm}5%$. Magnetic resonance images and partially computerized tomography images of the volunteer were acquired. The intervals between the transverse images were 1 mm for the head and 3 mm for the rest of the body. About 30 different tissues were manually classified by an anatomist on the raw images, and the segmented images were implemented in the form of a text file appropriate for numerical formulation.

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A Non-contact Detection Method for Smelting in Submerged Arc Furnace based on Magnetic Field Radiation

  • Liu, WeiLing;Chang, XiaoMing
    • Journal of Magnetics
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    • 제21권2호
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    • pp.204-208
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    • 2016
  • This paper demonstrates the key parameter detection for smelting of submerged arc furnace (SAF) based on magnetic field radiation. A magnetic field radiation model for the inner structure of SAF is established based on relative theory of electromagnetic field. A simple equipment of 3D magnetic field detection system is developed by theoretical derivation and simulation. The experiments are carried out under the environment of industrial field and AC magnetic field generated by electrode currents and molten currents in the furnace is reflected outside of the furnace. The experimental results show that the key parameters of smelting including the position of electrode tip, the length of electric arc, and the liquid level of molten bath can be achieved. The computed tomography for SAF can be realized by the detection for smelting.

정신분열병의 결핍증후군과 비결핍증후군에서 QEEG와 sLORETA를 이용한 비교연구 (Comparing Quantitative EEG and Low Resolution Electromagnetic Tomography Imaging between Deficit Syndrome and Non-Deficit Syndrome of Schizophrenia)

  • 이상은;임선진;이미경;이재원;한규희;이종일;심민영;윤해주;신병학
    • 수면정신생리
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    • 제17권2호
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    • pp.91-99
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    • 2010
  • 목 적: 본 연구는 정신분열병의 결핍증후군과 비결핍증후군이 다른 생물학적 동등성을 가진 독립된 질환일 수 있다는 가설 아래 quantitative EEG와 standardized LORETA (sLORETA)를 이용한 전기생리학적인 방법을 통하여 생물학적 병인을 파악하고자 시도되었다. 방 법: 정신분열병 환자를 대상으로 42명의 뇌파를 비교 분석하였으며 그 중 결핍증후군 환자군은 남자 10명과 여자 11명이었고 비결핍증후군 환자군은 남자 12명, 여자 9명이었다. 주파수 대역은 delta(1.5~4 Hz), theta(4~8 Hz), alpha(8~12 Hz), low beta(12~15 Hz), high beta(15~30 Hz)의 5가지로 분할하였고 EEG LAB을 이용한 파워스펙트럼 분석 및 standardized sLORETA software package를 이용하여 신호원을 국소화 하였다. 결 과: 파워 스펙트럼 분석에서 결핍증후군 집단은 비결핍증후군과 비교하였을 때 전두엽, 두정엽 및 측두엽 영역에서 delta파와 theta파의 유의한 활성도 증가를 보였으며 뇌파 스펙트럼은 간편 정신상태 평정 척도 중 철퇴/지연과 적대/의심 항목의 임상적인 특징과 유의한 상관관계를 보였다. sLORETA분석 결과에서는 배측 전대상피질에서 결핍증후군에서 유의하게 delta파의 활성도가 증가되었다. 결 론: 결핍증후군은 비결핍증후군과는 연관된 뇌 영역이 다를 수 있으며 특히 전두엽 영역의 신경회로 이상이 일차적 음성증상에 영향을 줄 것으로 생각된다.

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유방암 진단 시스템을 위한 정합 액체의 전파 특성에 관한 연구 (Study of Microwave Propagation Characteristics of Matching Liquids for the Microwave Cancer Detection System)

  • 김장렬;;이광재;손성호;전순익
    • 한국전자파학회논문지
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    • 제25권4호
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    • pp.442-450
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    • 2014
  • 본 논문은 피부를 포함하는 유방 모델에서 정합 액체의 전파 특성에 관한 연구 내용이다. 정합 액체의 분석을 위해 6개 타입의 정합 액체를 제안된 1-D 유방 모델에 적용하여 3~6 GHz의 주파수 대역에서 분석 연구를 수행하였다. 균일한 평면파가 1-D 유방 모델 내부의 복합 매질의 경계면에 입사되어 반사/투과되어 나타나는 전파 특성과 각 정합 액체의 전송 선로 손실을 분석하였다. 본 논문에서 연구한 방법은 유방암 진단 시스템, 인체 조직을 이용한 암 진단 분야 및 기타 의료기기 분야에 활용될 수 있으며, 본 논문에서는 유방암 진단 시스템에 적용하였다. 본 연구는 향후 유방암 진단 시스템에 적용될 적절한 정합 액체를 선정하고, 성능을 분석하는데 유용하게 적용될 수 있다.

임펄스 초광대역 레이다를 이용한 점표적의 ISAR 기하 보정 방법 (A Method of ISAR Geometric Calibration for Point Target Using Impulse-Radio UWB)

  • 유지웅;니키틴 콘스탄틴;백인찬;장종훈;가민호
    • 한국전자파학회논문지
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    • 제26권4호
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    • pp.397-403
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    • 2015
  • 본 논문은 임펄스 초광대역 레이다를 이용한 ISAR 영상의 기하보정 방법에 대해 서술하였다. 임펄스 초광대역 레이다는 시간영역에서 신호처리를 하므로 다중 경로, 간섭 문제 등이 일어나지 않는 장점이 있다. 안테나와 대상체 사이의 송수신 신호를 평면파라고 가정하면, ISAR 기하 모델에서 회전축의 중심을 점표적을 이용하여 계산한다. 수신 데이터에서 합성을 수행하기 전, 점표적은 최대 점의 위치를 최소 자승법으로 근사하여 회전축의 중심을 알아낼 수 있다. 이 방법은 대조비가 더 뛰어난 영상을 얻을 수 있었고, 엔트로피도 가장 큰 값을 가질 수 있었다. 이러한 방법은 장비를 최초 작동하거나 주기적으로 사용되어서 회전축의 중심을 보상하여 영상 합성을 할 것이다. 의료나 보안 감시와 같은 고정된 기하를 가지는 영상화 장비에서 유용하게 사용될 것이다.

Study on terahertz (THz) photoconversion technology based on hyperfine energy-level splitting of Positronium (Ps) generated from relativistic electron beams

  • Sun-Hong Min;Chawon Park;Ilsung Cho;Minho Kim;Sukhwal Ma;Won Taek Hwang;Kyeong Min Kim;Seungwoo Park;Min Young Lee;Eun Ju Kim;Kyo Chul Lee;Yong Jin Lee;Bong Hwan Hong
    • 대한방사성의약품학회지
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    • 제6권2호
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    • pp.102-115
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    • 2020
  • In the state of Positronium (Ps), which is an unstable material created by the temporary combination of electrons and positrons, the imaging technology through photo-conversion methodology is emerging as a new research theme under resonance conditions through terahertz electromagnetic waves. Normally, Positronium can be observed in the positron emission computed tomography (PET) process when an unstable, separate state that remains after the pair annihilation of an electron and a positron remains. In this study, terahertz (THz) waves and Cherenkov radiation (CR) are generated using the principle of ponderomotive force in the plasma wake-field acceleration, and electrons and positrons are simultaneously generated by using a relativistic electron beam without using a PET device. We confirm the possibility of Positronium photoconversion technology in terahertz electromagnetic resonance conditions through experimental studies that generate an unstable state. Here, a relativistic electron beam (REB) energy of 0.5 MeV (γ=2) was used, and the terahertz wave frequencies is G-band. Meanwhile, a THz wave mode converting three-stepped axicon lens was used to apply the photoconversion technology. Through this, light emission in the form of a luminescence-converted Bessel beam can be verified. In the future, it can be used complementarily with PET in nuclear medicine in the field of medical imaging.

Critical Enhancement of Photothermal Effect by Integrated Nanocomposites of Gold Nanorods and Iron Oxide on Graphene Oxide

  • Yun, Kum-Hee;Seo, Sun-Hwa;Kim, Bo-Mi;Joe, Ara;Han, Hyo-Won;Kim, Jong-Young;Jang, Eue-Soon
    • Bulletin of the Korean Chemical Society
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    • 제34권9호
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    • pp.2795-2799
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    • 2013
  • Irradiation of gold nanorods (GNRs) with laser light corresponding to the longitudinal surface plasmon oscillation results in rapid conversion of electromagnetic energy into heat, a phenomenon commonly known as the photothermal effect of GNRs. Herein, we propose a facile strategy for increasing the photothermal conversion efficiency of GNRs by integration to form graphene oxide (GO) nanocomposites. Moreover, conjugation of iron oxide (IO) with the GO-GNR nanohybrid allowed magnetic enrichment at a specific target site and the separated GO-IO-GNR assembly was rapidly heated by laser irradiation. The present GO-IO-GNR nanocomposites hold great promise for application in various biomedical fields, including surface enhanced Raman spectroscopy imaging, photoacoustic tomography imaging, magnetic resonance imaging, and photothermal cancer therapy.

뇌자도를 이용한 어휘적 중의성의 처리와 관련된 대뇌 신경활동 분석 (Magnetoencephalographic Study on the cerebral neural activities related to the processing of lexically ambiguous words)

  • 유기순;김준식;정천기;남기춘
    • 대한음성학회:학술대회논문집
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    • 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
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    • pp.59-63
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    • 2007
  • Neuromagnetic fields were recorded from normal 10 subjects to investigate the time course of cerebral neural activation during the resolution of lexical ambiguity. All recordings were made using a whole-head 306-channel MEG (Elekta Neuromag TM Inc., $Vectorview^{TM}$). The observed activity was described by sLORETA (standardized low resolution brain electromagnetic tomography) techniques implemented in CURRY software (Neuroscan). In the results, bilaterally occipito-temporal lobe was activated at 170ms. At 250ms was associated with bilateral temporal lobe during ambiguous condition, whereas in left parietal, temporal lobe on unambiguous condition. The left frontal lobe, temporal lobe were activated at 350ms for all condition. At approximately 430ms, was activated in right frontal, temporal lobe on the resolving ambiguous condition, in left parietal lobe, right temporal lobe on the preserving ambiguous condition. In conclusion, the cerebral activations related to the resolving lexical ambiguity were right frontal lobe and the areas of mountainous ambiguity were left parietal lobe.

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Efficient crosswell EM tomography for monitoring geological sequestration of $CO_2$

  • Lee, Ki-Ha;Kim, Hee-Joon;Song, Yoon-Ho
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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    • pp.321-327
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    • 2003
  • [ $CO_2$ ] sequestration in oil reservoirs can be one of the most effective strategies for long-term removal of greenhouse gas from atmosphere. This paper presents an advantage of the localized nonlinear approximation of integral equation solutions for inverting crosswell electromagnetic data, which are observed as a part of pilot project of $CO_2$ flooding at the Lost Hills oil field in central California, U.S.A. To monitor the migration of $CO_2$, we have used 2-D cylindrically symmetric and 2.5-D tomographic inversion methods. These two schemes produce nearly the same images if the borehole separation is large compared with the skin depth. However, since the borehole separation is much less than five skin depths in this $CO_2$ injection experiment, the 2.5-D model seems to be more reliable than the 2-D model. In fact, the pre-injection 2.5-D image is more successfully compared with induction logs observed in the two wells than the 2-D model. From the time-lapse crosswell imaging, we can confirm the replacement of brine with $CO_2$ makes a decrease of conductivity.

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