• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.303-303
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• 2007

Photo-imageable thick-film lithography technology was developed for the fabrication of embedded passives such as inductors and capacitors. In this study, photo-imageable dielectric and conductor pastes have apoted a negative type. Sodalime glass wafer, alumina substrate and zero-shrinkage LTCC green tapes were used as substrates. In result, The lithographic patterns were designed as lines and spaces for conductor material, or via-holes for ceramic, LTCC, materials. The scattering and reflection of UV-beam on the substrate had negative effects on fine patterning. The patterning performance was varied with the exposing and developing process conditions, and also varied with the substrate materials. Fine resolution of less then $50/50{\mu}m$ in line and space was obtained, which is difficult in screen printing method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.617-620
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• 1999

To reduce the consumption of chemicals and ultra pure water(UPW) in cleaning process used in device manufacturing, we proposed wet processes that use electrolytic ionized water(EIW), which is generated by electrolysis of a diluted electrolyte solution or UPW and systemically investicate the EIW\`s characteristics. EIW\`s pH values are increased in cathode chamber and decreased in anode chamber according to the electrolysis time and its varied ratio is reduced with time increasement. The variation of pH and ORP is increased accordin to the applied voltage until critical voltage. But more than that voltage, the variation is decreased because of ion\`s scattering effect. When electrolyte is added, the effects of electrolysis is increased because electrolyte acts as catalyst. But when the density of electrolyte is increased more than critical value, ion\`s flowage is obstructed and the effects of electrolysis is decreased.

• Bulletin of the Korean Chemical Society
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• 제16권10호
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• pp.957-968
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• 1995

Generalized Multichannel Quantum Defect theory (MQDT) was implemented to the vibrational predissociation of triatomic van der Waals molecules in the previous paper [Bull. Korean Chem. Soc, 12, 228 (1991)]. Implementation was limited to the calculation of the scattering matrix. It is now extended to the calculation of the predissociation spectra and the final rotational distribution of the photofragment. The comparison of the results with those obtained by other methods, such as Golden-rule type calculation, infinite order sudden approximation (IOS), and close-coupling method, shows that the implementation is successful despite the fact that transition dipole moments show more energy dependence than other quantum defect parameters. Examination of the short-range channel basis functions shows that they resemble angle-like functions and provide the validity of the IOS approximation. Besides the validity of the latter, only a few angles are found to play the major role in photodissociation. In addition to the implementation of MQDT, more progress in MQDT itself is made and reported here.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.73-80
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• 2013

In the process of lithography using ultra violet light sources for semiconductor devices, most of defects are made by sub-micrometer pollutants generated at photochemical reactions. We proposed and developed a novel vibration-insensitive on-axis interferometer with a sub-micrometer lateral resolution by using the interference between two beams: one scattered from defects and the other reflected from a reference area without defects. The proposed system was successfully demonstrated to detect a small Al defect of 0.5 ${\mu}m$ diameter within the inspection time of less than 30 minutes over the area of the photo-mask which is 6 inch by 6 inch square.

• 한국게임학회 논문지
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• 제21권4호
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• pp.109-116
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• 2021

In this paper, we considered that recently 3D game characters have been almost alike realistic expression because of a great mathematical computation and efficient techniques on GPU hardware. We presented the rendering technique and analysis for 3D game characters to simulate and render mathematical approach model from recent researches to perform the game engine for the surface reflection of lighting model. We compare our approach with the existing variant rendering techniques here using Open GL shader language on game engine. The experimental result will be provided the view-dependent visual appearance of variant and effective modeling characters for realistic expression using existing methods on the GPU for effective simulations and rendering process. Since there are many operations that are used redundantly while performing mathematical operations, the necessary functions and requirements have been to compute in advance.

• Current Optics and Photonics
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• 제5권6호
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• pp.617-626
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• 2021

A parallel Monte Carlo photon migration algorithm for graphics processing units that implements an improved load-balancing strategy is presented. Conventional parallel Monte Carlo photon migration algorithms suffer from a computational bottleneck due to their reliance on a simple load-balancing strategy that does not take into account the different length of the mean free paths of the photons. In this paper, path-partition load balancing is proposed to eliminate this computational bottleneck based on a mathematical formula that parallelizes the photon path tracing process, which has previously been considered non-parallelizable. The performance of the proposed algorithm is tested using three-dimensional photon migration simulations of a human skin model.

• 천문학회보
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• 제46권2호
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• pp.56.3-56.3
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• 2021

In a ΛCDM universe, most galaxies are believed to evolve by mergers and accretions. The debris resulting from such processes remains faint and/or diffuse structures, such as tidal streams and stellar halos. Although these structures are a good indicator of the recent mass assembly history of galaxies, they have the disadvantage of being difficult to observe due to their low surface brightness (LSB). To recover these LSB features by reducing the photometric uncertainties introduced by the optics system, we attempt to develop an optimized telescope, called a linear astigmatism free-three mirror system, that minimizes the loss and scattering of light within the telescope. With that prototype, we observe NGC 5907, known as a nearby galaxy with a fabulous loop structure(s), to inspect its performance. After a dedicated data reduction process, including flat-fielding with dark sky flat and sky subtraction, our observation reaches a 1σ surface brightness limit of μlim,r ≃ 28.3 mag arcsec-2 in 10×10 arcsec boxes. We finally identify a single tidal stream that is likely the remnant of a nearly disrupted galaxy. This finding emphasizes that the capability of LSB detection with our telescope is comparable to that of much larger telescopes.

• 자원리싸이클링
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• 제24권3호
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• pp.34-43
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• 2015

철강 산업에서의 원재료는 생산성, 품질, 가격경쟁력에 결정적인 역할을 하고 있다. 철강제품의 원재료를 함철부산물로 활용한다면, 함철부산물을 처리하기 위한 비용 및 환경오염문제를 해결할 뿐만 아니라 가격경쟁력을 높일 수 있다. 함철부산물들은 대부분 작읍입도를 가지고 있어서, 제강공정 내에 직접 투입하게 되면 열 유동 및 원료 비산 등의 문제가 발생하게 된다. 이러한 문제점을 해결하고 추가적인 환원을 유도하기 위해 철원에 탄재를 혼합한 뒤 단괴를 성형하여 제강공정 내에 투입하는 방법이 연구되고 있다. 본 연구에서는 함철부산물에 탄재를 혼합하여 단괴를 성형하는 방법에 대해 연구하였다. 함철부산물, 탄재, 융제, 바인더에 따른 CCBI (carbon composite briquette iron)의 성형성 및 압축강도를 확인하였다.

• 대한기계학회논문집B
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• 제28권12호
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• pp.1557-1566
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• 2004

A flame extinction phenomenon is a typical unsteady process in combustion. Flame extinction is characterized by various physical phenomena, such as convection, diffusion, and the production of heat and mass. Flame extinction can be achieved by either increasing the strain rate or curvature, by diluting an inert gas or inhibitor, or by increasing the thermal or radiant energy loss. Though the extinction is an inherently transient process, steady and quasi-steady approaches have been used as useful tools for understanding the flame extinction phenomenon. Recently, unsteady characteristics of flames have been studied by many researchers, and various attempts have been made to understand unsteady flame behavior, by using various extinction processes. Representative parameters for describing flame, such as flame temperature, important species related to reactions, and chemi-luminescence of the flame have been used as criterions of flame extinction. In these works, verification of each parameter and establishing the proper criterions of the extinction has been very important. In this study, a time-dependent flame temperature and an OH radical concentration were measured using optical methods, and the instantaneous change of the flame luminosity was also measured using a high-speed ICCD (HICCD) camera. We compare the unsteady extinction points obtained by three different methods, and we discuss transient characteristics of maximum flame temperature and OH radical distribution near the extinction limit.

• 한국재료학회지
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• 제11권2호
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• pp.104-114
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• 2001

Zr-Sn-Nb 합금의 재결정에 미치는 Nb과 Sn의 첨가영향을 연구하기 위해 냉간압연한 시편을 $300^{\circ}C$~75$0^{\circ}C$의 온도구간에서 열처리한 후에 미소경도와 TEP (Thermoelectric Power)를 측정하여 재결정 거동을 조사하였으며 광학현미경, 주사전자 현미경 (SEM), 투과전자현미경 (TEM)으로 미세조직을 관찰하였다 미소경도 및 미세조직의 분석 결과에 따르면, Nb과 Sn의 첨가에 의해 재결정 활성화 에너지가 증가하여 재결정이 지연되었으며, 재결정 완료 이후의 결정립 성장도 억제되었음을 관찰하였다. Zr내의 고용도가 매우 낮은 Nb의 첨가는 석출물을 쉽게 형성하는 반면에 고용도가 비교적 큰 Sn은 기지상 내에 대부분 고용되어 석출물의 양이 매우 작았으나, Sn 첨가에 의한 재결정의 지연 효과가 더욱 컸다. Nb보다 Sn의 첨가가 Zr 합금의 재결정 거동을 효과적으로 지연시킨 것은 고용도가 높은 SR에 의한 치환형 고용체 형성과정에서 발생된 응력장이 전위의 이동을 효과적으로 억제했기 때문으로 생각된다. 한편, 회복과 재결정이 진행됨에 따라 전자 산란인자의 감소로 TEP는 증가하였으며, 재결정이 완료되면 TEP의 포화가 발생하였다. 석출물의 형성은 석출물 주변의 용질농도 감소로 인한 전자 산란인자의 감소에 기인하여 TEP의 증가를 가져왔다