• 마이크로전자및패키징학회지
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• 제29권4호
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• pp.55-61
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• 2022

다중 암의 동시 진단 기술에 대한 관심이 전 세계적으로 증가하는 추세이며, 진단 난이도를 낮추기 위해 혈액과 같은 미량의 바이오 유체를 이용하여 질병을 진단하는 미세 유체 소자 기반의 액체 생검 기술이 연구되고 있다. 바이오 유체를 이용하여 형광 영상 등을 통해 분석물질의 농도를 측정하는 광학적 바이오 센싱에 있어 민감도를 향상시키기 위한 기술개발이 필요하다. 본 논문에서는 모세관력에 의한 자가구동 기반의 마이크로 채널의 기하학적 구조와 미세 유체 현상만으로 수동적 자기 혈장 분리 기술과 유체 혼합을 통한 분자 인식 활성화 기능을 구현하는 형광 다중 암 진단 센서 플랫폼 구조를 제안하고 설계하였다. 설계된 센서의 혈장 분리부의 성능에 영향을 미치는 파라미터를 확인하기 위해 채널의 수력학적 직경과 종횡비, 유체의 점도를 변수로 설정하여 딘 와류 형성 여부를 시뮬레이션을 통해 확인하였고 최적의 센서 플랫폼 구조를 제시하였다.

• 한국방사선학회논문지
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• 제3권1호
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• pp.17-21
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• 2009

최근 의료진단 분야와 다른 적용분야를 위해 대면적 매트릭스 구조의 엑스선 영상이 활발하게 연구되어 오고 있다. 본 연구에서는, 의료진단을 위한 새로운 평판형 디지털 엑스선 가스 검출기를 제안하고 그에 따른 특성을 검증하고자 한다. 대기압에 반해 가스를 주입하는 어려움 때문에 챔버 형태의 구조로 만들어 질 뿐, 평판형 디지털 엑스선 가스 검출기는 아직 어디에서도 연구된 바 없다. 이에 본 연구에서는 디스플레이 패널 제작 기술을 이용하여 샘플제작을 성공하였다. 실험적인 측정을 위해 만들어진 샘플은 상판에는 유리기판위에 전극, 절연층, 산화마그네슘 보호막을 형성하였으며, 하판에는 엑스선 형광층과 전극을 형성하였다. 누설전류와 엑스선 민감도를 측정하였으며, 전기장에 대한 민감도의 선형성 측정 등의 전기적 특성평가를 실시하였다. 이에 대한 결과로 안정된 누설전류와 엑스선 민감도를 얻었다. 그리고 조사 선량에 따라 좋은 선형성을 보이는 등 넓은 진단 동적영역을 확인할 수 있었다. 이러한 결과로 평판형 엑스선 가스 검출기의 디지털 엑스선 영상 검출기로의 적용 가능성을 확인 할 수 있었다.

• Journal of Oral Medicine and Pain
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• 제42권2호
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• pp.29-34
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• 2017

Purpose: To evaluate aggravating factors of intermittent locking among temporomandibular joint using magnetic resonance imaging (MRI) and diagnostic criteria for temporomandibular disorder (DC/TMD) diagnosis. Methods: A retrospective analysis was conducted of 35 patients with intermittent locking history but normal intra-articular findings between September 2012 and June 2015 in Kyung Hee University Dental Hospital. A standardized DC/TMD assessment was performed on subjects with MRI findings. Clinical findings were assessed on the basis of maximum mouth opening (active & passive), self-reported habits, patients' age, gender, systemic diseases at the initial visit. First, chi square test was used to examine differences with variables and then risk factors for intermittent locking were assessed using multivariate logistic regression. Results: Self-reported bruxism was strongly associated with intermittent locking history. Conclusions: The new DC/TMD protocol is intended for use within any clinical setting and supports the full range of diagnostic activities from screening to definitive evaluation and diagnosis. Self-reported sleep bruxism has been associated with a higher likelihood of intermittent locking. Comorbidity is therefore a factor that must be assessed. It is necessary to consider the amount of contact of the teeth and the duration.

• Journal of Korean Neurosurgical Society
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• 제58권3호
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• pp.242-247
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• 2015

Objective : The purpose of this study is to determine whether the changes of contralateral sensorimotor cortical activation on functional magnetic resonance imaging (fMRI) can predict the neurological outcome among spinal cord injury (SCI) patients when the great toes are stimulated without notice. Methods : This study enrolled a total of 49 patients with SCI and investigated each patient's preoperative fMRI, postoperative fMRI, American Spinal Injury Association (ASIA) score, and neuropathic pain occurrence. Patients were classified into 3 groups according to the change of blood oxygenation level dependent (BOLD) response on perioperative fMRI during proprioceptive stimulation with repetitive passive toe movements : 1) patients with a response of contralateral sensorimotor cortical activation in fMRI were categorized; 2) patients with a response in other regions; and 3) patients with no response. Correlation between the result of fMRI and each parameter was analyzed. Results : In fMRI data, ASIA score was likely to show greater improvement in patients in group A compared to those belonging to group B or C (p<0.001). No statistical significance was observed between the result of fMRI and neuropathic pain (p=0.709). However, increase in neuropathic pain in response to the signal change of the ipsilateral frontal lobe on fMRI was statistically significant (p=0.030). Conclusion : When there was change of BOLD response at the contralateral sensorimotor cortex on perioperative fMRI after surgery, relief of neurological symptoms was highly likely for traumatic SCI patients. In addition, development of neuropathic pain was likely to occur when there was change of BOLD response at ipsilateral frontal lobe.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2361-2369
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• 2020

Compton cameras using large scintillators have been developed for high imaging sensitivity. These scintillator-based Compton cameras, however, mainly due to relatively low energy resolution, suffer from undesired background-radiation signals, especially when radioactive materials' activity is very low or their location is far from the Compton camera. To alleviate this problem for a large-size Compton camera, in the present study, a hybrid-type shielding system was designed that combines an active shield with a veto detector and a passive shield that surrounds the active shield. Then, the performance of the hybrid shielding system was predicted, by Monte Carlo radiation transport simulation using Geant4, in terms of minimum detectable activity (MDA), signal-to-noise ratio (SNR), and image resolution. Our simulation results show that, for the most cases, the hybrid shielding system significantly improves the performance of the large-size Compton camera. For the cases investigated in the present study, the use of the shielding system decreased the MDA by about 1.4, 1.6, and 1.3 times, increased the SNR by 1.2-1.9, 1.1-1.7, and 1.3-2.1 times, and improved the image resolution (i.e., reduced the FWHM) by 7-8, 1-6, and 3-5% for ¹³⁷Cs, ⁶⁰Co, and ¹³¹I point source located at 1-5 m from the imaging system, respectively.

• Clinical and Experimental Pediatrics
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• 제49권5호
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• pp.570-573
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• 2006

대요근은 12번 흉추의 외연면에서 5번 요추까지의 외연면에 걸쳐 기시하여 대퇴골의 소전자에 부착되는 근육으로 고관절의 굴곡에 관여한다. 이는 후복막 기관으로 여러 혈관에서 풍부한 혈류 공급을 받으며, S자 결장, 공장, 충수 돌기, 요관, 대동맥, 신장, 췌장, 척추, 림프선 등 여러 장기와 인접하고 있어 감염의 호발 부위가 된다. 그러나, 요근 농양 발생시, 그 증상이 비특이적이고 건강한 소아에서 드물게 발병하는 이유로 고관절 질환으로 혼돈되기도 하여, 진단과 치료가 지연되는 예가 많다. 저자들은 평소 건강하던 14세 남아가 침대에서 떨어져 경한 우측 둔부 좌상을 입은 이후, 우측 둔부 통증과 발열 및 보행 불능을 호소하여 고관절 이상을 의심해 시행한 자기 공명 영상에서 우연히 우측 요근내 농양을 발견해 항생제 치료를 시행하였던 증례를 경험하였기에 보고하는 바이다.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.139-147
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• 2007

The aim of this study was to evaluate effects of short-tenn repetitive-bilateral excercise on the activation of motor network using functional magnetic resonance imaging (fMRI). The training program was performed at 1 hr/day, 5 days/week during 6 weeks. Fugl-Meyer Assessments (FMA) were performed every two weeks during the training. We compared cerebral and cerebellar cortical activations in two different tasks before and after the training program: (1) the only unaffected hand movement (Task 1); and (2) passive movements of affected hand by the active movement of unaffected hand (Task 2). fMRI was performed at 3T with wrist flexion-extension movement at 1 Hz during the motor tasks. All patients showed significant improvements of FMA scores in their paretic limbs after training. fMRI studies in Task 1 showed that cortical activations decreased in ipsilateral sensorimotor cortex but increased in contralateral sensorimotor cortex and ipsilateral cerebellum. Task 2 showed cortical reorganizations in bilateral sensorimotor cortex, premotor area, supplemetary motor area and cerebellum. Therefore, this study demonstrated that plastic changes of motor network occurred as a neural basis of the improvement subsequent to repetitive-bilateral excercise using the symmetrical upper-limb ann motion trainer.

• 천문학회보
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• 제42권2호
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• pp.75.1-75.1
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• 2017

Ram pressure due to the intracluster medium (ICM) is known to play a crucial role in removing the cool gas content of a galaxy on a short timescale, potentially driving a star forming galaxy to evolve into a red passive population. Although many HI imaging studies find clear evidence of diffuse atomic gas stripping from cluster galaxies, it is still debatable whether the ram pressure can also strip dense molecular gas. NGC 4522, a Virgo spiral, undergoing strong ram pressure stripping, is one of the few cases where extraplanar CO emission together with stripped HI gas and $H{\alpha}$ knots has been identified, providing an ideal laboratory to study the molecular gas stripping event and the extraplanar star formation activity. The aim of this work is to investigate the origin of extraplanar molecular clouds near NGC 4522 (e.g. stripped or forming in situ), and to probe a relation between the molecular gas surface density and the star formation rate (i.e. the Kennicutt-Schmidt law) at sub-kpc scale, especially in the extraplanar space, using ALMA Cycle 3 CO data and $H{\alpha}$ data of NGC 4522. We present the results from our ALMA observations, and discuss possible scenarios for the origin of extraplanar molecular clouds and to characterize the star formation activity associated with stripped gas outside the galactic disk.

• 비파괴검사학회지
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• 제35권5호
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• pp.341-348
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• 2015

능동적 열화상 기법은 재료의 수동적 열적결함에 있어 기존의 적외선 열화상 기법에 비해 우수한 결함 검출능력을 보이는 것으로 알려져 있다. 적외선 비파괴 검사는 지금까지 다양한 검출 기법에 대한 발전이 이루어졌으나 신뢰성에는 다소 의문이 있다. 따라서 본 논문에서는 위상잠금 열화상기법을 적용하여 각각 다른 결함의 크기와 깊이의 인공결함을 갖는 SM45C 시험편을 가지고 제안된 기법을 검증하고, 불확도를 평가하여 위상잠금 열화상 기법을 이용한 결함의 크기측정에 대한 신뢰성을 검토하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.149-152
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• 1999

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about loom underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the way of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. In the hybrid method, both informations of time-delays and power-ratios are coupled together to produce better performance of position estimation. A new acoustic imaging technique has been developed for improving the hybrid method. For each method the sound localization is carried out in three dimensions underground. The minimum distance between the true and estimated origins of the source is 28 m for a search area of radius 250m.