• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1320-1322
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• 2005

Microcrystalline silicon films were deposited on glass substrate by using plasma-enhanced chemical vapor deposition (PECVD) method. The crystalline volume fraction was estimated by means of Raman spectrometer with argon laser as light source. The high hydrogen dilution of silane gas was used for increase in content of crystal silicon phase.

• 대한화장품학회지
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• 제30권3호
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• pp.361-367
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• 2004

본 연구는 poly(methyl methacrylate) (PMMA) 마이크로 입자 내의 상 조절을 통하여 자외선 A 흡수제인 butyl metho-xydibenzoylmethane (BMDM)을 효과적으로 안정화시킨 새로운 자외선 흡수 시스템에 관한 것으로, 마이크로 입자 내의 BMDM의 광학특성을 고분자와의 상 특성에 연관하여 해석함으로써 자외선 A 흡수제의 분자거동과 광 에너지 흡수 거동을 체계적으로 이해하고자 하였다. 본 연구에서는 고분자 마이크로 입자 내에서 BMDM의 상 특성을 제어하여, BMDM의 광 및 열 안정성을 유지하면서 자외선 A를 효과적으로 차단할 수 있었다. 본 연구를 통하여 고분자 마이크로 입자 내에 자외선 흡수제의 상 특성을 조절하는 것이 자외선 흡수제를 함유하는 화장품 제형 내에서 광화학 및 광 안정도를 결정하는 중요한 인자임을 알 수 있었다.

• 시스템엔지니어링학술지
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• 제19권1호
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• pp.79-90
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• 2023

In principle, R&D of general weapons systems are led by companies or government-funded organizations. In terms of project execution, the defense R&D planning system was reorganized to conduct SE-based project management by integrating the naval ship project execution procedure into the general weapon system R&D procedure. The development progress was confirmed according to the guide for SE application of DAPA, and a technical review meeting was proposed to enter into the each next phase in the R&D process. This paper focuses on improvement for technical review in terms of technical management based on system engineering for R&D mounted weapon systems and the naval surface ship project in preliminary design and detailed design. So, the improvement direction for reviewing the entry criteria for the R&D weapons systems of the naval ship and mounted weapons is proposed.

• 센서학회지
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• 제27권3호
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• pp.186-191
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• 2018

Smart textile industries have been precipitously developed and extended to electronic textiles and wearable devices in recent years. In particular, owing to an increasingly aging society, the elderly healthcare field has been highlighted in the smart device industries, and pressure sensors can be utilized in various elderly healthcare products such as flooring, mattress, and vital-sign measuring devices. Furthermore, elderly healthcare products need to be more lightweight and flexible. To fulfill those needs, textile-based pressure sensors is considered to be an attractive solution. In this research, to apply a textile to the second layer using a pressure sensing device, a novel type of conductive textile was fabricated using vapor phase polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). Vapor phase polymerization is suitable for preparing the conductive textile because the reaction can be controlled simply under various conditions and does not need high-temperature processing. The morphology of the obtained PEDOT-conductive textile was observed through the Field Emission Scanning Electron Microscope (FESEM). Moreover, the resistance was measured using an ohmmeter and was confirmed to be adjustable to various resistance ranges depending on the concentration of the oxidant solution and polymerization conditions. A 3-layer 81-point multi-pressure sensor was fabricated using the PEDOT-conductive textile prepared herein. A 3D-viewer program was developed to evaluate the sensitivity and multi-pressure recognition of the textile-based multi-pressure sensor. Finally, we confirmed the possibility that PEDOT-conductive textiles could be utilized by pressure sensors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1046-1048
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• 2002

The increase of triplen harmonics in three-phase four-wire systems leads to overloaded neutral conductor, common-mode noise problems, derating of transformers, and so on. Various compensator has been designed to prevent the problems associated with the triplen harmonics. But these can not protect distribution system effectively because the triplen harmonic source is distributed extensively and distribution system type is diverse. This paper explain the operation and installation of single phase active power filter to eliminate triplen harmonics and then it is verified by simulation.

• 한국분말재료학회지
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• 제25권3호
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• pp.246-250
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• 2018

In this study, we investigate the deformation behavior of $Hf_{44.5}Cu_{27}Ni_{13.5}Nb_5Al_{10}$ metallic glass powder under repeated compressive strain during mechanical milling. High-density (11.0 g/cc) Hf-based metallic glass powders are prepared using a gas atomization process. The relationship between the mechanical alloying time and microstructural change under phase transformation is evaluated for crystallization of the amorphous phase. Planetary mechanical milling is performed for 0, 40, or 90 h at 100 rpm. The amorphous structure of the Hf-based metallic glass powders during mechanical milling is analyzed using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Microstructural analysis of the Hf-based metallic glass powder deformed using mechanical milling reveals a layered structure with vein patterns at the fracture surface, which is observed in the fracture of bulk metallic glasses. We also study the crystallization behavior and the phase and microstructure transformations under isothermal heat treatment of the Hf-based metallic glass.

• 한국재료학회지
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• 제11권2호
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• pp.88-93
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• 2001

$N_2$처리에 의해 Si (001) 기판에 형성된 C49상의 구조를 갖는 에피택셜 $TiSi_2$상의 열적 거동과 결정학적 특성을 X선 회절법 (XRD)과 고분해능 투과전자현미경법 (HRTEM)으로 조사하였다. 에피택결 $C49-TiSi_2$상은 $1000^{\circ}C$ 정도의 고온에서도 안정상인 C54상으로 상변태하지 않고 형태적으로도 고온 특성이 우수하다는 것이 밝혀졌다. HRTEM 결과로부터 에피택결 $TiSi_2$상과 Si 사이의 결정학적 방위관계는 (060) [001]TiSi$_2$//(002) [110]Si임을 알 수 있었고 계면에서의 격자 변형에너지는 misfit 전위의 형성에 의하여 해소되는 것을 확인할 수 있었다. 또한 HRTEM상의 해석과 원자 모델링을 통하여 Si에서 에피택셜 C49-TiSi$_2$상의 형성기구와 C49상의 (020) 면에 존재하는 적층결함을 고찰하였다.

• Nuclear Engineering and Technology
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• 제37권6호
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• pp.511-524
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• 2005

Thermalhydraulic reactor simulation of tomorrow will require a new generation of codes combining at least three scales, the CFD scale in open medium, the component scale and the system scale. DNS will be used as a support for modelling more macroscopic models. NEPTUNE is such a new generation multi-scale platform developed jointly by CEA-DEN and EDF-R&D and also supported by IRSN and FRAMATOME-ANP. The major steps towards the next generation lie in new physical models and improved numerical methods. This paper presents the advances obtained so far in physical modelling for each scale. Macroscopic models of system and component scales include multi-field modelling, transport of interfacial area, and turbulence modelling. Two-phase CFD or CMFD was first applied to boiling bubbly flow for departure from nucleate boiling investigations and to stratified flow for pressurised thermal shock investigations. The main challenges of the project are presented, some selected results are shown for each scale, and the perspectives for future are also drawn. Direct Numerical Simulation tools with Interface Tracking Techniques are also developed for even smaller scale investigations leading to a better understanding of basic physical processes and allowing the development of closure relations for macroscopic and CFD models.

• 대한화장품학회지
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• 제30권2호
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• pp.147-151
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• 2004

본 연구는 다양한 종류의 에멀젼에 전단응력을 가하며 그때 일어나는 에멀젼의 상 변이를 전기, 유변학적 특징을 통해 실시간으로 측정해 보는 것이다. 전기 전도도의 변화는 자체 제작한 JELLI$^{TM}$(Joint Electro-rheometer for Liquid-Liquid Inversion) 칩을 이용하였으며, 동시에 유변물성측정장치(rheometer)를 이용하여 유변물성의 변화를 측정하였다 JELLI$^{TM}$ 칩과 인조 피부를 유변물성측정장치 사이에 장착하고 그 사이에 다양한 종류의 에멀젼을 얇게 발라준 후, 일정한 전단응력을 주며 시간에 따른 저항과 점도 값의 변화를 측정하였다. O/W 제형의 경우 시간에 따라 저항 값이 커지는 경향을 보였으며 저항 값은 내부 상이 많을수록 더 급격한 변화를 나타냈다. 이때의 점도 변화를 보면, 저항 값의 변화가 클수록 점도의 변화도 큼을 볼 수 있었다. 이것은 내부 상의 파괴로 인해 외부의 힘에 저항하는 힘이 약해졌기 때문이라고 예상된다. 이런 결과를 이용하여 전단응력에 의한 에멀젼 상 변이 특성과 정도를 실시간, 정량적 비교할 수 있었다.

• Journal of Information Display
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• 제12권3호
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• pp.115-119
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• 2011

Optically isotropic liquid crystal (LC) mixture such as blue-phase LC and nanostructured LC composites exhibit the advantages of fast response time, high contrast ratio and wide-viewing angle due to the induced birefringence along the horizontal electric field. Utilizing this mixture, a novel single cell gap in-plane switching-type polymer-stabilized blue-phase transflective liquid crystal display by embedding the nanowire grid polarizer as a polarization-dependent reflective polarizer in the R region is proposed. This device can be used as a normal black mode without any quarter-wave plate or patterned in-cell phase retarder. Moreover, the transmittance is identical to the reflectance so that it will be suitable for single gamma driving. Detailed electro-optic performances, such as voltage-dependent light efficiency and viewing angle of the proposed device configuration, are investigated.