• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.251-251
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• 2012

A lot of studies are undergoing on the magneto-optical (MO) properties of patterned magnetic systems for the reason that they have potential application to information technology such as ultrahigh-speed computing. Moreover, they can be considered as the future candidates for high-density MO storage devices. Not only the technical aspects, but there have been also tremendous interests in studying their properties related to the fundamental physics. The MO Kerr-rotation effects (both in reflected and the diffracted modes) and the magnetic force microscopy (MFM) are very useful techniques to investigate the micromagnetic properties of such periodic structures. Hence, in this study, we report on the MO properties of bilayered Cobalt (Co)/ nickel (Ni) micro-patterned anti-dot arrays. Such a ferromagnetic structure was made by sequentially depositing co (40 nm)/Ni (5 nm) bilayer on a Si substrate. The anti-dot patterning with hole diameter of $1{\mu}m$ was done only on the upper Co layer using photolithography technique, while the Ni underlayer was kept uniform. The longitudinal Kerr rotation (LKR) of the zeroth- and the first-order diffracted beams were measured at an incidence of $30^{\circ}$ by using a photoelastic modulator method. The external magnetic field was applied perpendicularly to the reflected and the diffracted beams using an electromagnet capable of a maximum field of ${\pm}5$ kOe. Significantly, it was observed that the LKR of the first-order diffracted beam is nearly 4 times larger than that of the zeroth-order beam. The simulated results for the hysteresis loops matched qualitatively well with the experimentally obtained ones. In conjunction with the LKR, we also investigated the magnetic-domain structure by using a MFM system, which were analyzed to elucidate the origin of the enhanced MO rotation.

• 센서학회지
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• 제8권2호
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• pp.184-188
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• 1999

Pulsed laser deposition법에 의하여 양질의 PbTe 박막을 다양한 기판온도에 따라 성장시켰다. XRD패턴으로 부터 각 온도에서의 PbTe층들은 결정화가 되어있음을 알 수 있었다. 또한 PbTe 박막의 XRD 피크들은 (h00)의 방향성을 나타내고 있다. Pb의 재증발로 인하여 $400^{\circ}C$이상에서는 PbTe 박막은 결정성의 박막으로 형성되지 않았다. AFM 이미지로부터 박막의 표면은 작은 granular 결정들과 평탄한 매트릭스로 구성되어 있음이 관찰되었다. 기판온도의 증가에 따라 표면의 입자들이 커지는 것을 알 수 있었다. Hall-effect 측정으로부터 $300^{\circ}C$에서 성장한 PbTe 박막의 전기적 특성은 $3.68{\times}10^{18}cm^{-3}$의 캐리어 농도와 $148\;cm^2/Vs$의 Hall 이동도를 나타내었다.

• 인터넷정보학회논문지
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• 제20권6호
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• pp.95-103
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• 2019

최근 1인 가구가 다양한 연령대에서 증가하고 있으며 무연고자의 사망도 점차 증가한다. 1인 가구의 무연고사의 경우 주위에 돌봐줄 사람이 없어 많이 발생하며 최근에는 노인뿐만 아니라 다양한 연령대에서 발생한다. 우리는 혼자 사는 사람의 이상 징후를 탐지하고자 홈 CCTV를 이용한 영상 패턴 알고리즘과 음성을 인식하는 음성 패턴 알고리즘, 움직임 및 요리 등에서 발생하는 먼지를 탐지하는 센서로 먼지 패턴 알고리즘을 연구 및 개발하였다. 개별적으로 제안된 패턴 알고리즘은 탐지 영역을 벗어나게 되면 탐지하지 못하는 단점이 존재한다. 개별 패턴 알고리즘의 성능을 향상시키기 위해 융합 방식을 연구했으며, 다수의 사용자 행동 패턴을 분석하여 그 성능을 검증하였다.

• Archives of Reconstructive Microsurgery
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• 제22권1호
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• pp.29-32
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• 2013

Purpose: Reconstruction of scalp and calvarial defects should provide both aesthetic and functional aspects. The inelastic nature of the scalp and previous surgery or radiation preclude the use of primary closure or a local flap. With development of microsurgical technique, a free tissue transfer is a good option. We use the latissimus dorsi myocutaneous free flap for reconstruction. Materials and Methods: A review of all latissimus dorsi free flap reconstructions performed in nine patients from 2009 to 2012 was conducted. There were six males and three females, ranging in age from seven to 69 years, and nine different regions, including five temporal regions, two occipital regions, and two frontoparietal regions. The flaps ranged in size from $9.0{\times}10.0cm$ to $14.0{\times}15.0cm$. Recipient vessels available for microanastomosis were most often the superficial temporal vessels and two patients had anastomoses to the external carotid artery and internal jugular vein. Results: All flaps survived postoperatively. With a median follow-up period of 14 months, no major complications were noted. However, two patients developed minor wound dehiscence, and a hematoma was observed in one patient. Conclusion: We performed the latissimus dorsi myocutaneous free flap reconstruction, which is one of the most popular reconstructive methods. The latissimus dorsi myocutaneous free flap reconstruction has been proven successful in our patients with satisfactory results. During the long term follow-up period, even though depressions were observed on the defect area in some patients, they were treated successfully with cranioplasty. Therefore, we recommend the latissimus dorsi myocutaneous free flap for reconstruction of scalp and calvarial defects.

• 한국콘텐츠학회논문지
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• 제11권5호
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• pp.84-92
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• 2011

바이오 영상에서 세포 영역의 자동 분할 기술은 생물학자들이 복잡한 세포의 기능을 이해하는데 도움을 주고, 수작업을 통해 세포를 분석하던 일들을 자동적으로 처리해주는 매우 중요한 기술이다. 기존의 멀티채널 영상으로부터 세포핵 및 세포를 분할하는 방법은 DNA 채널을 이용하여 세포핵을 검출하고, 이를 초기 윤곽으로 하여 Actin 채널에서 밝기 기반의 Active Contour 모델을 통해 세포를 분할하는 2 단계의 과정을 거친다. 그러나 세포 분할 과정에서 채널 간 상관성으로 인해 발생하는 세포 내 불균일한 밝기 문제를 고려하지 않은 채, 밝기 기반의 Active Contour 모델을 적용하여 분할의 성능이 저하되는 문제점이 발생한다. 따라서 본 논문에서는 DNA 와 Actin 채널 간 상관성을 고려하여, DNA 채널 정보를 통해 Actin 채널 내부의 밝기를 균일하게 보정함으로써 밝기 기반의 Active Contour 모델이 세포 분할에 잘 적용 될 수 있는 전처리 알고리즘을 제안한다. 실험을 통해 제안 전처리 과정을 거친 세포 분할 방법의 성능이 기존 방법에 비해 객관적, 주관적으로 크게 향상됨을 증명한다.

• Advances in pediatric surgery
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• 제8권1호
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• pp.11-15
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• 2002

This is a 20 year analysis of the problems associated with enterostomy formation, and closure. Forty-three stomas were established in 43 patients: 23 for anorectal malformations, 11 for Hirschsprung's diseases, 4 for necrotizing enterocolitis, 3 for multiple ileal atresias, 1 for volvulus neonatorum with perforation, and 1 for diaphragmatic hernia with colon perforation. Thirty boys and 13 girls were included (mean age 4.8 months). Stoma complications were encountered in 13 patients (30.2 %): stomal prolapse, stenosis, obstruction, paracolic hernia, retraction, dysfunction, and skin excoriation, Four patients (9.3 %) required stomal revision. Occurrence of complications was not related to age and primary disease, but sigmoid colostomy showed lower complication rate than transverse colostomy (20.0 % vs 42.9 %, p<0.05). There were five deaths but, only one (2.3 %) was directly related to the enterostomy complication. Twenty-one stomas were closed in our hospital and complications occurred in seven patients (33.3 %). The most common complication was wound sepsis in 5 children. In conclusion, because the significant morbidity of stomal formation still exists, refinements of the surgical technique seem to be required, Sigmoid loop colostomy is preferred whenever possible.

• 구강회복응용과학지
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• 제22권1호
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• pp.101-110
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• 2006

This study was performed to investigate the surface properties and in vitro biocompatibility of electrochemically oxidized Ti-6Al-7Nb alloy by anodic spark discharge technique. Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed using a regulated DC power supply. The applied voltages were given at 240, 280, 320, and 360 V and current density of $30mA/cm^2$. Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. Samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ during 30 days. The results obtained were summarized as follows; 1. The oxide films were porous with pore size of $1{\sim}5{\mu}m$. The size of micropores increased with increasing the spark forming voltage. 2. The main crystal structure of the anodic oxide film was anatase type as analyzed with thin-film X-ray diffractometery. 3. Needle-like hydroxyapatie (HA) crystals were observed on anodic oxide films after hydrothermal treatment at $300^{\circ}C$ for 2 hours. The precipitation of HA crystals was accelerated with increasing the spark forming voltage. 4. The precipitation of the fine asperity-like HA crystals were observed after being immersed in Hanks' solution at $37^{\circ}C$. The precipitation of HA crystals was accelerated with increasing the spark forming voltage and the time of immersion in Hanks' solution. 5. The Ca/P ration of the precipitated HA layer was equivalent to that of HA crystal as increasing the spark forming voltage and the time of immersion in Hanks' solution.

• 한국세라믹학회지
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• 제54권2호
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• pp.141-149
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• 2017

The influence of the co-additive concentration (0 - 45 wt% with an interval of 5 wt%) of MgO-$TiO_2$ on the phase formation, microstructure and fracture toughness of MgO-$TiO_2$-reinforced dental porcelain nanocomposites derived from a one-step sintering technique were examined using a combination of X-ray diffraction, scanning electron microscopy and Vickers indentation. It was found that MgO-$TiO_2$-reinforced dental porcelain nanocomposites exhibited significantly higher fracture toughness values than those observed in single-additive (MgO or $TiO_2$)-reinforced dental porcelain composites at any given sintering temperature. The amount of MgO-$TiO_2$ as a co-additive was found to be one of the key factors controlling the phase formation, microstructure and fracture toughness of these nanocomposites. It is likely that 30 wt% of MgO-$TiO_2$ as a co-additive is the optimal amount for $MgTi_2O_5$ and $Mg_2SiO_4$ crystalline phase formation to obtain the maximum relative density (96.80%) and fracture toughness ($2.60{\pm}0.07MPa{\cdot}m^{1/2}$) at a sintering temperature of $1000^{\circ}C$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.659-659
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• 2013

Recently, graphene has been intensively studied due to the fascinating physical, chemical and electrical properties. It shows high carrier mobility, high current density, and high thermal conductivity compare with conventional semiconductor materials even it has single atomic thickness. Especially, since graphene has fantastic electrical properties many researchers are believed that graphene will be replacing Si based technology. In order to realize it, we need to prepare the large and uniform graphene. Chemical vapor deposition (CVD) method is the most promising technique for synthesizing large and uniform graphene. Unfortunately, CVD method requires transfer process from metal catalyst. In transfer process, supporting polymer film (Such as poly (methyl methacrylate)) is widely used for protecting graphene. After transfer process, polymer layer is removed by organic solvents. However, it is impossible to remove it completely. These organic residues on graphene surface induce quality degradation of graphene since it disturbs movement of electrons. Thus, in order to get an intrinsic property of graphene completely remove of the organic residues is the most important. Here, we introduce modified wet graphene transfer method without PMMA. First of all, we grow the graphene from Cu foil using CVD method. And then, we deposited several metal films on graphene for transfer layer instead of PMMA. Finally, we fabricate graphene FET devices. Our approaches show low defect density and non-organic residues in comparison with PMMA coated graphene through Raman spectroscopy, SEM and AFM. In addition, clean graphene FET shows intrinsic electrical characteristic and high carrier mobility.

• 대한공간정보학회지
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• 제18권4호
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• pp.109-117
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• 2010

본 논문은 용수공급 2축의 한방향인 공급관리의 효율화를 개선하는 한 방안을 제시하는데 그 궁극적인 목적을 두고 있다. 그 총체적 접근의 일환으로 생활용수 중 상업용수를 대상으로 공간분석 대상지 선정, 센서 설치위치 선정, 센서 및 서버시스템의 설치, 실시간 데이터 모니터링 등의 일련의 과정을 시도했다. 이러한 과정을 거쳐 수집된 실시간 데이터 분석을 통해 요일별, 월별 용수사용 추세패턴 모형을 개발하였다. 또한 개발된 추세패턴 모형과 GIS시스템의 연계방안을 제안하였다. 모형의 신뢰도 향상과 더불어 상기 제시된 접근 및 결과는 물사용 예측행정 및 관리를 위한 주요한 도구의 역할을 수행할 수 있을 것으로 기대된다.