• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1533-1538
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• 2008

The development of new material systems like Carbon Fiber Reinforced Polymer (CFRP) places ever higher demands on the techniques for non-destructive material characterisation. Image-producing eddy current methods also need to satisfy these demands. Eddy-current imaging of FRP is based on the anisotropic electrical properties of the material investigated. Significant differences in conductivity between carbon fibres, polymer matrix and integrated functional components can be found. The availability of high-resolution sensors enables access to the local distribution of the electromagnetic properties. The static and dynamic procedures for isolating influential characteristics, already in use in eddy-current technology, can now be supplemented by topographical images. The precondition for a successful implementation of the eddy-current procedure is a deeper understanding of the image-generating process which allows correct interpretation of the images obtained.

• Journal of Korean Neurosurgical Society
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• 제52권6호
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• pp.570-573
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• 2012

Avulsion of spinous process, also called Clay-shoveler's fracture, is most prevalent among those engaged in hard physical labor. To the best of the author's knowledge, only one case of multiple spinous process fractures of the upper thoracic spine in a novice golfer has been reported. A 45-year-old female presented with intractable posterior neck pain. The patient experienced a sharp, sudden pain on the neck while swinging a golf club, immediately after the club head struck the ground. Dynamic cervical radiographic findings were C6 and C7 spinous process fractures. Magnetic resonance imaging revealed C6 and C7 spinous process fractures without spinal cord pathology. The patient was treated with pain medications and cervical bracing. The patient's pain gradually improved. The injury mechanism was speculated to be similar to Clay-shoveler's fracture. Lower cervical spinous process fractures can be associated with a golf swing. If the patient complains of long lasting neck pain and has a history of golf activity, further study should be conducted to rule out lower cervical spinous fracture.

• 한국정밀공학회지
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• 제20권4호
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• pp.92-102
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• 2003

To detect electrical faults of a TFT (Thin Film Transistor) panel for the LCD (Liquid Crystal Display), techniques of converting electric field to an image are used One of them is the PDLC (polymer-dispersed liquid crystal) modulator which changes light transmittance under electric field. The advantage of PDLC modulator in the electric field detection is that it can be used without physically contacting the TFT panel surface. Specific pattern signals are applied to the data and gate electrodes of the panel to charge the pixel electrodes and the image sensor detects the change of transmittance of PDLC positioned in proximity distance above the pixel electrodes. The image represents the status of electric field reflected on the PDLC so that the characteristic of the PDLC itself plays an important role to accurately quantify the defects of TFT panel. In this paper, the image of the PDLC modulator caused by the change of electric field of the pixel electrodes on the TFT panel is acquired and how the characteristics of PDLC reflect the change of electric field to the image is analyzed. When the holding time of PDLC is short, better contrast of electric field image can be obtained by changing the instance of applying the driving voltage to the PDLC.

• Nuclear Medicine and Molecular Imaging
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• 제41권4호
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• pp.335-336
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• 2007

Meniscus-like presentation of ulcerating gastric carcinoma on upper gastrointestinal series radiograph was first described in 1921 by Carman and has since been known as a useful differential diagnostic sign in radiology. In 1982 using then newly introduced computed tomography (CT) Widder and Mueller revisited the meniscus sign. Their study was primarily focused on a dynamic assessment of the demonstrability of the meniscus sign that largely depends on the judgment and technical skill of examiner, especially graded compression and patient positioning. One year earlier Balfe et al. assessed the diagnostic reliability of gastric wall thickening as observed on CT scan in adenocarcinoma, lymphoma and leiomyosarcoma and concluded that it is not a reliable finding. In contrast, however, Lee et al. recently emphasized that the wall thickness measurement on CT of exophytic carcinoma, myoma and ulcers was a useful diagnostic means. Thus, it appears that gastric wall thickening or mucosal heave-up is by itself not as reliable as the meniscus sign. The electronic search of world literature failed to disclose earlier report of this sign demonstrated by $^{18}F-FDG$ positron emission tomography and computed tomography (PET/CT). The present communication documents $^{18}F-FDG$ PET/CT finding of the meniscus sign as encountered in a case of ulcerating gastric carcinoma, the histological diagnosis of which was moderately differentiated tubular adenocarcinoma. Unlike most gastric tumors without ulceration that tend to unimpressively accumulate $^{18}F-FDG$ the present case of Borrmann type III gastric carcinoma demonstrated markedly increased $^{18}F-FDG$ uptake.

• 신재생에너지
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• 제3권2호
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• pp.24-30
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• 2007

The transient response of PEMFC (proton exchange membrane fuel cell) is important criteria in the application of PEM fuel cell to real automotive system. In this work, using a transparent unit PEM fuel cell, the transient response and cathode flooding during load change are investigated. The cell voltage is acquired according to the current density change($0.3Acm^2$ to $0.6A/cm^2$) under various stoichiometry conditions and different flooding intensities, Also the cathode gas channel images are obtained by CCD imaging system simultaneously. The different level of undershoots appeared at the moment of load changes under different cathode stoichiometries and flooding intensities. It takes about 1s that the product water comes up onto the flow channel so that oxygen supply is temporarily blocked which causes voltage loss in that "undershoot". The correlation of the dynamic behavior with stoichiometry and cathode flooding is induced from the results of these experiments.

• Journal of the Optical Society of Korea
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• 제18권2호
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• pp.174-179
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• 2014

Since in vitro neural recording and imaging applications based on a surface plasmon resonance (SPR) technique have expanded dramatically in recent years, cytotoxicity assessment to ensure the biosafety and biocompatibility for those applications is crucial. Here, we report the cytotoxicity of the SPR substrate incorporating a flint glass whose refractive index is larger than that of a conventional crown glass. A high refractive index glass substrate is essential in neural signal detection due to the advantages such as high sensitivity and wide dynamic range. From experimental data using primary hippocampal neurons, it is found that a lead-based flint glass is not appropriate as a neural recording template although the neuron cells are not directly attached to the toxic glass. We also demonstrate that the adhesion layer between the glass substrate and the gold film plays an important role in achieving the substrate stability and the cell viability.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.817-818
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• 2006

In Magnetic Resonance Imaging(MRI), the QRS complex of ECG is used as a trigger signal for MRI scan. But, gradient and RF(radio frequency) artifacts which are caused to static and dynamic field in MRI scanner cause interference in the ECG. Also, the signal shape of theses artifacts can be similar to the QRS-complex, causing possible misinterpretation during patient monitoring and false gating of the MRI. In case of using general FIR or IIR band-pass filters for minimizing the artifacts, artifact-reduction-ratio is not excellent. So, an adaptive real-time digital filter is proposed for reduction of noise by gradient and RF(radio frequency) artifacts. The proposed filter for MRI-Gating is based on the noise-canceller with NLMS(Normalized Least Mean Square) algorithm. The reference signals of the adaptive noise canceller are a combination of the noisy three channel ECG signals. In conclusions, the proposed method showed the acceptable quality of ECG signal with sufficient SNR for gating the MRI and possibility of real time implementation.

• Tuberculosis and Respiratory Diseases
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• 제83권3호
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• pp.195-200
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• 2020

The disease concept of interstitial lung disease with idiopathic pulmonary fibrosis at its core has been relied on for many years depending on morphological classification. The separation of non-specific interstitial pneumonia with a relatively good prognosis from usual interstitial pneumonia is also based on the perception that morphology enables predict the prognosis. Beginning with dust-exposed lungs, initially, interstitial pneumonia is classified by anatomical pathology. Diagnostic imaging has dramatically improved the diagnostic technology for surviving patients through the introduction of high-resolution computed tomography scan. And now, with the introduction of therapeutics, the direction of diagnosis is turning. It can be broadly classified into to make known the importance of early diagnosis, and to understand the importance of predicting the speed of progression/deterioration of pathological conditions. For this reason, the insight of "early lesions" has been discussed. There are reports that the presence or absence of interstitial lung abnormalities affects the prognosis. Searching for a biomarker is another prognostic indicator search. However, as is the case with many chronic diseases, pathological conditions that progress linearly are extremely rare. Rather, it progresses while changing in response to environmental factors. In interstitial lung disease, deterioration of respiratory functions most closely reflect prognosis. Treatment is determined by combining dynamic indicators as faithful indicators of restrictive impairments. Reconsidering the history being classified under the disease concept, the need to reorganize treatment targets based on common pathological phenotype is under discussed. What is the disease concept? That aspect changes with the discussion of improving prognosis.

• Investigative Magnetic Resonance Imaging
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• 제14권2호
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• pp.145-150
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• 2010

소아에서 췌장의 악성 종양은 매우 드물게 발생하고 있으며, 특히 악성 신경내분비 종양은 더더욱 드물다. 저자들은 16세 소아 환자에서 발생한 비기능성 악성 신경내분비 종양의 증례를 경험하여 CT와 MRI 소견을 보고하고자 한다. 췌장 두부에서 발생한 고형 종양으로 조영증강 MRI의 문맥기에서 지연기로 갈수록 조영증강이 잘 되고, 주변의 혈관 침습, 총담관 폐색, 림프절병증 등 악성 소견을 동반할 때 췌장의 비기능성 악성 신경내분비 종양을 감별 진단에 포함하여야 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권4호
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• pp.375-385
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• 2016

Given the rapid progress made in understanding the dynamics of an offshore floating body in an ocean environment, the present study aimed to simulate ocean waves in a small-sized wave flume and to observe the motion of a cylindrical floating body placed in an offshore environment. To generate regular ocean waves in a wave flume, we combined a wave generator and a wave absorber. In addition, to precisely visualise the oscillation of the body, a set of light-emitting diode illuminators and a high-speed charge-coupled device camera were installed in the flume. This study also focuses on the spectral analysis of the movement of the floating body. The wave generator and absorbers worked well to simulate stable regular waves. In addition, the simulated waves agreed well with the plane waves predicted by shallow-water theory. As the period of the oncoming waves changed, the movement of the floating body was substantially different when tethered to a tension-leg mooring cable. In particular, when connected to the tension-leg mooring cable, the natural frequency of the floating body appeared suddenly at 0.391 Hz as the wave period increased.