• 방송공학회논문지
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• 제28권1호
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• pp.31-41
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• 2023

재생하고자 하는 3차원 이미지에서 발현되는 빛의 간섭 무늬를 계산하여 얻게 되는 Computer Generated Hologram(CGH)은 본래의 3차원 이미지와 유사관계를 찾기 힘든 형태로 형성되기에 직접적인 초점 위치 혹은 크기 등의 변환이 어려운 것으로 알려져 있다. 본논문은 이러한 문제 중 하나인 다중 평면으로 구성된 3차원 이미지 CGH의 평면별 초점 거리를 변환하는 문제를 해결하는 기술을 제안한다. 제안하는 기술은 CGH로부터 재생되는 3차원 이미지를 여러 각도에서 관측한 2차원 이미지의 집합으로 구성된 Light-Field (LF) 이미지로 변환하고, 관측한 각도별로 이동하는 객체의 위치를 객체 탐지 알고리즘인 YOLOv5(You Only Look Once version 5)로 분석한 뒤, 이를 조절함으로써 초점 거리가 변환된 LF 이미지와 이를 역변환한 결과인 CGH를 생성한다. 해당 기술은 CGH의 픽셀 사이즈가 3.6 ㎛, 해상도가 3840⨯2160인 상황에서 10 cm 거리에 재생되는 상에 적용되어 영상 품질의 큰 손실 없이 약 3 cm 정도의 범위에서 초점 거리를 변환시킬 수 있음을 시뮬레이션 분석과 실제 실험 관측을 통해 확인하였다.

• Imaging Science in Dentistry
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• 제30권2호
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• pp.123-126
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• 2000

Pyogenic granuloma is a overzealous proliferation of a vascular type connective tissue as a result of some minor trauma and is a well circumscribed elevated, pedunculated or sessile benign inflammatory lesion of skin and mucous membrane. The clinical features of pyogenic granuloma are indicative but not specific and nearly all cases of pyogenic granulomas are superficial in nature, and there is little if any mention in the literature of these lesions producing alveolar bone even jaw bone loss. This case is somewhat unique in that the lesion was an obvious histologic pyogenic granuloma; however, it appeared to invade the mandibular bone which resulted in the loss of the adjacent teeth. A 12-year-old boy came to Seoul National University Dental Hospital with chief complaints of left facial swelling. The features obtained were as follows; Plain radiograms showed a large well-circumscribed radiolucent lesion on left mandibular ramus area, which made severe expansion of lingual cortex and displacement of lower left 3rd molar tooth germ. Computed tomograms showed large soft tissue mass involving left masticator space with destruction of left mandibular ramus. Histologically, sections revealed loose edematous stroma with intense infiltration of inflammatory cells and proliferation of vascular channels. Also, there were focal areas of extensive capillary proliferation, bone destruction and peripheral new bone formation.

• 대한핵의학회지
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• 제25권2호
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• pp.237-244
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• 1991

$^{99m}Tc-DMSA$ renal scan has been evaluated not only the renal functional cell mass but also some anatomical structures at a loss of the renal parenchymal function. The author classified a renal morphology of the posterior image of $^{99m}Tc-DMSA$ renal scan as the groups of symmetric and asymmetric morphology, the groups of the large, normal and small sized kidneys, the groups of the central photon defects (PD) which could be noted in a dilated pelvocalyceal system due to obstructive uropathy and the cortical photon defects (CD) due to focal parenchymal lesions or scars after a loss of function and the last groups of the single and multiple CD for a suggestion of the clinical usefulness. Regarding to measurement of normal renal size, the longest size of the kidneys were evaluated with 5 cm of a lead scale on the posterior renal image, and those were decided to the limits beteen 104.1 and 119.4 mm as comparison with the renal size of intravenous pyelogram (IVP) in 59 cases who were underwent $^{99m}Tc-DMSA$ and IVP concommitantly. Among 85 cases of PD in $^{99m}Tc-DMSA$ renal scan, the 61 (71.8%) were cases of a dilated pelvocalyceal system related with obstructive uropathy, meanwhile the 28 (27.0%) of 162 cases with CD were cases of obstructive and infectious uropathy. The probability of a presence of some uropathy in cases of CD were 99.3%, meanwhile that of the presence of CD in cases of some uropathy were 37.9%. Besides, there were some specific anatomical findings such as polycystic kidneys with symmetric enlarged kidneys with multiple CD and the kidneys of chronic renal failure and/or hypertension with symmetric small size in $^{99m}Tc-DMSA$ renal stan.

• 한국식품영양학회지
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• 제15권1호
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• pp.7-11
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• 2002

학령전 아동의 zinc absorption, excretion, balance에 대하여 연구한 결과는 다음과 같다. Zinc absorption은 남자아동의 경우 29.7%, 여자아동의 경우 23.3%, 평균 25.8%로 나타났다. 대상자기 zinc absorption은 zinc intake와는 상관성이 나타나지 않았으며, zinc balance와 유의적 상관(p<0.01)을 보였다. Zinc balance는 남자아동의 경우 평균 3.25mg/day , 여자아동의 경우 1.78mg/day , 평균 2.34mg/day 로 1명의 대상자를 제외하고 모두 positive balance를 보였다. Fecal zinc loss는 평균 6.31mg/day, urinary ziilc loss는 평균 0.16mg/day 였다. zinc intake는 focal zinc loss및 zinc balance에 유의적 영향을 미치는 것으로 나타났으며(p<0.01), urinary zinc는 intake의 영향을 받지 않았다. 우리나라 학령전 아동의 zinc absorption 및 balance 는 양호한 것으로 나타났다. 그러나 이 방면의 연구 자료가 많지 않아, 성장기 아동을 대상으로 한 zinc nutrition에 대한 구체적이고 지속적인 연구가 필요하다.

• Applied Microscopy
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• 제20권1호
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• pp.65-76
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• 1990

The effect of calcium-free reperfusion for 5, 10, and 15 minutes, respectively, followed by continuous reperfusion with normal Tyrode solution containing 1.0mM calcium chloride, after global ischemia in the isolated perfused guinea pig heart by Langendorff techniques was examined with transmission electron microscope. Compared to the nomal Tyrode solution-perfused control hearts, the 5 minute calcium-free-reperfused hearts showed loss or thickening of Z lines, focal sarcolemmal disruption, mitochondrial swelling, clumping of chroma-tin, intracellular fluid accumulation, and some separation of cell junctions, especially the fasciae adherentes. These changes became more severe in the hearts of 10 minute calcium-free reperfusion. Subsarcolemmal larger bleb and near complete separation of cell junctions were noticed. In the 15 minute calcium-free-reperfused hearts, irreversible ultrastructural changes including contraction bands, biazrre mitochondria, and sarcolemmal destruction were widely distributed. The severity of myocardial changes were in accordance with the duration of calcium-free reperfusion. These changes indicate that calcium-free reperfusion regardless of its duration could not salvage the post-ischemic myocardium probably due to development of calcium paradox.

• Archives of Plastic Surgery
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• 제37권3호
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• pp.271-276
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• 2010

Purpose: The purpose is to present an useful and simple surgical method to improve the aging of upper third face in patients with high frontal hairline as well as low frontal hairline. Methods: Forty eight female patients were treated with subcutaneous forehead lift using an anterior hairline incision over 14 years. This surgical technique is performed under direct vision utilizing a beveled incision made 4 to 5 mm into the anterior hairline with subcutaneous dissection, which is continued near to eyebrow, sometimes extended to supraorbital rim to remove corrugator and procerus muscles. In patients with high frontal hairline, excess forehead skin anterior to incision line is removed. On the contrary in the patients with low frontal hairline, scalp posterior to incision line is removed. Results: This technique provided constant and good results with the forty six patients, who were satisfied with eyebrow elevation and removal of wrinkles in forehead and glabellar region. However two patients were undercorrected, and focal alopecia developed in another two patients. One patient complained of pruritus over one year, but subsided spontaneously without any treatment. Temporary paresthesia developed in the forehead and frontal scalp of all cases after operation but permanent sensory loss never occurred in all the patients. Conclusion: Subcutaneous forehead lift using an anterior hairline incision is suggested to be one of the effective surgical methods to improve the aging of upper third face in the patients with high frontal hairline as well as low frontal hairline.

• 한국군사과학기술학회지
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• 제7권4호
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• pp.53-60
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• 2004

In this paper, the radar antenna of navigation radar on helicopter was suggested to Ka-band lens antenna. It is type of the streamlined convex lens to reduce the air resistivity when helicopter was navigated. Although aperture area is smaller than the standard antenna just like horns, the gain is higher and beamwidth is smaller than standard horns. We made the lens by using maximum flare angle of the horn and dielectric constant of the lens. As a result, when aperture diameter was 280mm and focal length was 145mm, the return loss -21.25dB, the gain was 32.2dBi, E and H beamwidth was $1.8^{\circ}$(E-plane), $1.4^{\circ}$(H-plane), nearly $1.5^{\circ}$, and side-lobe level was -18.4 dB(E-plane), -19.5dB(H-plane) lower were presented. So this suggested type can be used for the radar antenna of navigation radar on helicopter, and it will possible just a little some sidelobe suppression by using the choked horn as a feeder horn.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1312-1316
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• 2007

Strip casted and rolled magnesium sheet is become exiting material for car manufacturer, due to its better formability and specific strength compare with conventional extruded sheet. TWB technology was attractive for car body designer, because it saves the weight of the car without strength loss. In this study, the laser welding performance of magnesium sheet was investigated for Mg TWB panel manufacturing. The material was strip casted and rolled magnesium alloy sheet contains 3 wt% Al and 1 wt% Zn (AZ31). Lamp pumped Nd:YAG laser of 2kW was used and its laser light was delivered by optical fiber of 0.6mm core diameter to material surface with focusing optics of 200mm focal length for TWB welding. The microstructure of weld bead was investigated to check internal defects such as inclusion, porosity and cracks. Also mechanical properties and formability were evaluated for press forming of car body. For the results, there was no crack but inclusion or porosity on weld at some conditions.The tensile strength of weld was over 95% of base metal. Inner and outer panel of engine hood were press formed and assembled at elevated temperature.

• 센서학회지
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• 제27권5호
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• pp.300-305
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• 2018

The uncooled microbolometer thermal sensor for low cost and mass volume was designed to target the new infrared market that includes smart device, automotive, energy management, and so on. The microbolometer sensor features 80x60 pixels low-resolution format and enables the use of wafer-level vacuum packaging (WLVP) technology. Read-out IC (ROIC) implements infrared signal detection and offset correction for fixed pattern noise (FPN) using an internal digital to analog convertor (DAC) value control function. A reliable WLVP thermal sensor was obtained with the design of lid wafer, the formation of Au80%wtSn20% eutectic solder, outgassing control and wafer to wafer bonding condition. The measurement of thermal conductance enables us to inspect the internal atmosphere condition of WLVP microbolometer sensor. The difference between the measurement value and design one is $3.6{\times}10-9$ [W/K] which indicates that thermal loss is mainly on account of floating legs. The mean time to failure (MTTF) of a WLVP thermal sensor is estimated to be about 10.2 years with a confidence level of 95 %. Reliability tests such as high temperature/low temperature, bump, vibration, etc. were also conducted. Devices were found to work properly after accelerated stress tests. A thermal camera with visible camera was developed. The thermal camera is available for non-contact temperature measurement providing an image that merged the thermal image and the visible image.

• Journal of Yeungnam Medical Science
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• 제13권2호
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• pp.360-366
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• 1996

Pure primary hepatic rhabdomyosarcoma in adult is very uncommon. There have been only five previous case of primary rhabdomyosarcoma of the adult liver. A case of hepatic rhabdomyosarcoma was diagnosed in a 52 year-old female. She was admitted to the hospital due to the epigastric pain and weight loss. A CT scan of the abdomen showed a large hypodense mass with focal calcification occupies most of the both lobes of the liver. The liver biopsy showed massive liver tumor composed entirely of oval shaped cells showing light microscopic and immunohistochemical evidence of rhabdomyoblastic differentiation. We report a case of hepatic rhabdomyosarcoma with review of literature.