• International Journal of Precision Engineering and Manufacturing
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• 제1권2호
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• pp.105-114
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• 2000

An output feedback control (OFC) is presented for a linear stochastic system with known disturbance and applied to a flexible spacecraft for the reduction of residual vibration while allowing the natural deflection during operation. By converting the tracking problem into regulator problem, the OFC minimizes the expected value of a guadratic objective function composing of error stats which always remain on the intersection of sliding hypersurfaces. For the numerical evaluation with a flexible spacecraft, a large slewing maneuver strategy is devised with a tracking model for nominal trajectory and start-cost-stop strategy for economical maneuver in conjunction with the input shaping technique. The performance and efficacy of the proposed control scheme are illustrated with the comparison of different maneuver strategies.

• 광산업정보
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• 통권4호
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• pp.44-47
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• 2001

• 광산업정보
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• 통권34호
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• pp.12-17
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• 2006

대만은 광산업 분야를 OE(Optoelectronics Components, FPD(Flat Panel Display), Optical Storage, Optical Lens Components & Laser Applications, OFC(Optical Fiber Communications, Optical Input & Output Devices 등 6개 대분류로 나누고 있으며 수년간 중점적으로 육성해 온 분야는 OE 및 FPD와 관련이 큰 LED 분야이다.

• 대한기계학회논문집B
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• 제40권9호
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• pp.589-596
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• 2016

최근 들어 작동유체가 액체 상태를 유지하며 흡열 과정이 일어나는 증기동력사이클인 유기플래시 사이클이 제안되었다. 본 연구에서는 재생을 이용한 수정 유기플래시 사이클을 제안하고 현열 형태의 저온 열원을 사용하는 시스템의 열역학적 성능 해석을 수행하였으며 작동유체나 플래시 온도가 순생산 동력이나 열효율 등 시스템의 성능에 미치는 영향을 체계적으로 분석하고 논의하였다. 해석 결과는 시스템의 순생산동력은 플래시 온도에 대해 최대값을 갖지만 열효율은 플래시 온도에 따라 상승함을 보여준다. 재생 사이클은 기존의 유기플래시 사이클에 비해 시스템 열효율이 높고 저온 열원의 동력 변환에 있어 성능 개선을 위한 잠재성을 보여준다.

• 한국초전도ㆍ저온공학회논문지
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• 제4권1호
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• pp.30-34
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• 2002

In this Paper, Insulation of current lead in the conduction-cooled DC reactor for the 1.2kV class 3 high-Tc superconducting fault current limiter(SFCL) is studied. Thermal link which conducts heat energy but insulates electrical energy is selected as a insulating device for the current lead in the conduction-cooled Superconducting DC reactor. It consists of oxide free copper(OFC) sheets, Polyimide films, glass fiberglass reinforced Plastics (GFRP) plates and interfacing material such an indium or thermal compound. Through the test of dielectric strength in L$N_2$, polyimide film thickness of 125 ${\mu}{\textrm}{m}$ is selected as a insulating material. Electrical insulation and heat conduction are contrary to each other. Because of low heat conductivity of insulator and contact area between electrical insulator and heat conductor, thermal resistance of conduction-cooled system is increased. For the reducing of thermal resistance and the reliable contact between Polyimide and OFC, thermal compound or indium can be used As thermal compound layer is weak layer in electrical field, indium is finally selected for the reducing of thermal resistance. Thermal link is successfully passed the test. The testing voltage was AC 2.5kVrms and the testing time was 1 hour.

• 대한금속재료학회지
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• 제47권2호
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• pp.121-128
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• 2009

The strain, microstructure and mechanical properties through thickness of an oxygen free copper(OFC) processed by differential speed rolling(DSR) were investigated in detail. The OFC sample with thickness of 1 mm was rolled to 35% reduction at ambient temperature without lubrication changing the differential speed ratio from 1.0:1 to 2.2:1. The shear strain introduced by the conventional rolling showed positive values at positions of upper roll side and negative values at positions of lower roll side. However, it showed zero or positive values at all positions for the samples rolled by the DSR. The effects of strain distribution through thickness of the coper sheets on microstructure, texture and mechanical properties are discussed in the present study.

• 한국도로학회논문집
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• 제8권2호
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• pp.23-30
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• 2006

상온아스팔트 혼합물은 생산공정이나 시공 중에 naphtha나 kerosene을 사용하는 컷백 아스팔트와 같이 환경오염물질을 생성하지 않고 골재와 아스팔트 바인더를 가열하지 않기 때문에 가열아스팔트 혼합물에 비하여 환경친화적이며 경제적이다. 그러나 일반적으로 상온아스팔트 혼합물은 가열아스팔트 혼합물에 비해 내구성이나 수분민감성에서 미흡한 점이 많다. 본 연구에서는 상온아스팔트의 수분민감성과 내구성을 증진시킬 수 있는 섬유보강 상온아스팔트 혼합물(FEAM)에 대한 평가를 하였다. 최적 유화아스팔트량(OEC), 최적함수량(OWC) 그리고 최적 섬유보강제 첨가량(OFC)를 결정하기 위해서 마샬배합설계를 수정 개발하였다. 최적의 섬유보강 상온아스팔트 혼합물과 일반 상온아스팔트 혼합물을 제작하여 마샬안정도 시험, 간접인장강도 시험 및 회복탄성계수 시험을 실시하였고 그 결과를 가열아스팔트 혼합물의 결과와 비교하였다. 결과로 FEAM과 EAM 모두 마샬배합설계 기준으로 중간 교통량에 충분한 것으로 판명되었다. 또한 섬유보강에 의하여 일반 상온아스팔트 혼합물의 수분민감성과 내구성이 증진하는 효과도 얻을 수 있는 것으로 판명되었다

• 광산업정보
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• 통권33호
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• pp.10-13
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• 2006

세계 최대 광관련전문전시회인 Photonics WEST2006이 지난 2006년 1월 24일부터 26일까지 미국 산호세 컨벤션센터에서 성황리에 개최되었다. 북미지역에서 OFC/NFOEC보다 주목받고 있는 전시회로써, 올해에는 전년도 보다 규모가 확대되어 1,100여개 업체가 참가하였으며, 7개 워크샵과 80개의 테크니컬프로그램 및 8개 시장동향 분석세미나가 개최되어, 전세계의 광산업 시장 동향 및 선진기술을 엿볼 수 있었다. 특히 이번 전시회는 SPIE(국제광기술학회)의 원만한 운영요령이 돋보인 세계최대의 광관련 전문전시회였다.

• 대한인간공학회지
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• 제33권5호
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• pp.377-386
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• 2014

Objective: In this study, we used resting-state fMRI data to map differences in functional connectivity between a comprehensive set of 8 distinct cortical and subcortical brain regions in healthy controls and Internet addicts. We also investigated the relationship between resting state connectivity strength and the level of psychopathology (ex. score of internet addiction scale and score of Barratt impulsiveness scale). Background: There is a lot of evidence of relationship between Internet addiction and impaired inhibitory control. Clinical evidence suggests that Internet addicts have a high level of impulsivity as measured by behavioral task of response inhibition and a self report questionnaire. Method: 15 Internet addicts and 15 demographically similar non-addicts participated in the current resting-state fMRI experiment. For the connectivity analysis, regions of interests (ROIs) were defined based on the previous studies of addictions. Functional connectivity assessment for each subject was obtained by correlating time-series across the ROIs, resulting in $8{\times}8$ matrixs for each subject. Within-group, functional connectivity patterns were observed by entering the z maps of the ROIs of each subject into second-level one sample t test. Two sample t test was also performed to examine between group differences. Results: Between group, the analysis revealed that the connectivity in between the orbito frontal cortex and inferior parietal cortex, between orbito frontal cortex and putamen, between the orbito frontal cortex and anterior cingulate cortex, between the insula and anterior cingulate cortex, and between amydgala and insula was significantly stronger in control group than in the Internet addicts, while the connectivity in between the orbito frontal cortex and insula showed stronger negative correlation in the Internet addicts relative to control group (p < 0.001, uncorrected). No significant relationship between functional connectivity strength and current degree of Internet addiction and degree of impulsitivy was seen. Conclusion: This study found that Internet addicts had declined connectivity strength in the orbitofrontal cortex (OFC) and other regions (e.g., ACC, IPC, and insula) during resting-state. It may reflect deficits in the OFC function to process information from different area in the corticostriatal reward network. Application: The results might help to develop theoretical modeling of Internet addiction for Internet addiction discrimination.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제10권2호
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• pp.117-128
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• 2007

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE mediated hypersensitivity disorder, which is associated with mainly gastrointestinal symptoms and has a delayed onset. The vomiting and/or diarrheal symptoms of FPIES typically begin in the first month of life in association with a failure to thrive, metabolic acidosis, and shock. Therefore, the differential diagnosis of FPIES and neonatal or infantile sepsis-like illnesses or gastroenteritis is difficult. The early recognition of indexes of suspicion for FPIES may help in the diagnosis and treatment of this disorder. The diagnosis of FPIES is generally made through clinical practice and food-specific IgE test findings are typically negative in this condition. Therefore, oral cow's milk challenge (OCC) remains the valid diagnostic standard for FPIES. An investigation of positive OCC outcomes helps to find out a diagnostic algorithm of criteria of a positive challenge in FPIES. Moreover, it has not been clearly determined in infantile FPIES when $1^{st}$ follow up-oral food challenge (FU-OFC) should be performed, with what kind of food protein (e.g., cow's milk, soy), and how much protein should be administered. Hence, to prevent the risk of inappropriate FU-OFC or accidental exposure and achieve appropriate dietary management, it is necessary to identify tolerance rates to major foods under the careful follow up of infantile FPIES patients. On the other hand, small intestinal enteropathy with villous atrophy is observed in FPIES and this enteropathy seems to be in part induced by both of epithelial apoptosis and intercellular junctional complex breakdown. The purpose of this report is to introduce an update on diagnostic and therapeutic approaches in FPIES and suggest the possible histopathological evidences in this disorder.