• Korean Journal of Metals and Materials
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• v.47 no.11
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• pp.748-753
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• 2009

The surface morphology and the surface roughness of n-type SiC induced by wet-treatment using 45% KOH and buffered oxide etchant (BOE-1HF : $6H_2O$) were investigated by atomic force microscopy (AFM). While Si-face of SiC could be etched by alkali solutions such as KOH, acidic solutions such as BOE were hardly able to etch SiC. When the rough SiC samples were used, the surface roughness of etched sample was decreased after wet-treatment regardless of etchant, due to the planarization the of surface by widening of scratches formed by mechanical polishing. It was observed that the initial etching was affected by the energetically unstable sites, such as dangling bond and steps. However, when a relatively smooth sample was used, the surface roughness was rapidly increased after treatment at $180^{\circ}C$ for 1 hr and at room temperature for 4 hr by using KOH solution, resulting from the nano-sized structures such as pores and bumps. This indicates that porous SiC surface can be achieved by using purely chemical treatment.

• Progress in Medical Physics
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• v.25 no.2
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• pp.116-121
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• 2014

Next future, The bio technology will be a rapidly developing. This paper is the scattering beam measurement of the red blood cell (RBC) and the fabrication of the micro cell biochip using the bio micro electro mechanical system (Bio-MEMS) process technology. The Major process method of Bio-MEMS technology was used the buffered oxide etchant (BOE), electro chemical discharge (ECD) and ultraviolet sensitive adhesives (UVSA). All experiments were the 10 times according to the process conditions. The experiment and research are required the ultraviolet expose, the micro fluid current, the cell control and the measurement of the output voltage Vpp (peak to peak) waveform by scattering angles. The transmitting and receiving of the laser beam was used the single mode optical fiber. The principles of the optical properties are as follows. The red blood cells were injected into the micro channel. The single mode optical fiber was inserting in the guide channel. The He-Ne laser beam was focusing in the single mode optical fiber. The transmission He-Ne laser beam is irradiating to the red blood cells. The manufactured guide channel consists of the four inputs and the four outputs. The red blood cell was allowed with the cylinder pump. The output voltage Vpp waveform of the scattering beam was measured with a photo detector. The receiving angle of the output optical fiber is $0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. The magnitude of the output voltage Vpp waveform was measured in the decrease according to increase of the reception angles. The difference of the output voltage Vpp waveform is due differences of the light transmittance of the red blood cells.

• The Journal of the Korean dental association
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• v.21 no.3 s.166
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• pp.195-198
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• 1983

저작, 발음, 미관등 3대기능회복에 주안점을 두어왔던 치과보철학은 근년에 와서 l아 및 그 주위조직, 악골 및 악관절, 저작근육들과 그들을 지배하는 신경계통등 구강악계(stomatognathic system)의 total treatment로 더욱 발전되어 가고 있다. 구강악계를 구성하는 조직들은 각기 독립적으로 저작, 발음, 연하등 그 기능적 행위에 참여하는 것이 아니라 서로 긴밀한 협조와 조화에 의하여 이루어 지기 때문에 어떠한 조직의 잘못된 치료는 한 개의 기능적 단위인 구강악계전체에 영향을 미치게된다. 그러므로 치과수복 치료에 있어서 단순한 인레이로 부터 전구강회복에 이르기까지 이들 보철물들은 기능운동시 다른 조직들과 잘 조화되어야 된다는 것은 당연한 사실이다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2008.05a
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• pp.23.2-23.2
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• 2008

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.70.2-70.2
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• 2020

공생별의 밝기 변화와 분광선 변화에 대한 지속적인 관측과 분석은 공생별 구성원의 구조, 거성으로부터의 질량 이동, 백색왜성 근처에서의 부착원반 형성과 이들의 진화에 대한 중요한 정보를 제공한다. 본 연구에서는 보현산 천문대 1.8-m 망원경과 고분산 에셀분광기 BOES를 이용하여 타 연구자에 의해 하룻밤 새 분광선 변화가 있다고 보고된 공생별 CH Cyg를 중심으로 AG Dra와 EG And의 방출선들에 대한 하룻밤 새 변화 모니터링 관측을 수행하였고, 이 세 공생별의 짧은 시간 내 분광적 변화 양상과 특성을 파악하고자 한다.

• Journal of the Korean Vacuum Society
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• v.13 no.1
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• pp.34-38
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• 2004

Hot embossing master is indispensable for the fabrication of polymeric optical waveguides using hot embossing technology. Sidewall roughness of silicon master is directly related to optical loss of optical waveguides In this paper, a silicon master was fabricated by using a deep-RIE process. Additionally, thermal oxidation followed by oxide removal was carried out to minimize etched Si sidewall roughness. Thermal oxidation and oxide removal were performed with $H_2O_2$ atmosphere at $1050^{\circ}C$ and $NH_4$F:HF=6:l BOE, respectively, for the oxide thickness of 400$\AA$, 1000$\AA$, 3000$\AA$, 4500$\AA$, 5600$\AA$ and 6200$\AA$. The sidewall roughness was characterized by SEM and SPM-AFH measurements. We found that the roughness was improved from 12nm (RMS) to 6nm (RMS) for the scalloped sidewall and from 162nm (RMS) to 39nm (RMS) for the vertical striation sidewall, respectively.

• Polymer(Korea)
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• v.28 no.4
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• pp.298-304
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• 2004

We fabricated a polymer dispersed liquid crystal (PDLC) cell using LC with negative dielectric anisotropy and UV curable monomer exhibiting transparent state initially (called normally transparent (NT)) and studied the electro-optic characteristics. The NT PDLC cell made with the ratio of LC : monomer = 70/30 wt%, curing temperature of 20 $^{\circ}C$ and strong UV intensity of 198 ㎽/$\textrm{cm}^2$ had high contrast ratio and showed good electro-optic characteristics. In this condition, LC is aligned vertically on the substrate due to the vertical alignment layer and the polymer made with the UV exposure does not influence the alignment of the LC much. Therefore, the transmittance at the zero voltage is very high and the scattering state of the cell is good after applying the voltage because LC with negative dielectric anisotropy tries to align perpendicular to the field. And also, the NT PDLC cell showed better viewing angle characteristics than that in the normally scattering (NS) PDLC.

• Fashion & Textile Research Journal
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• v.21 no.3
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• pp.267-276
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• 2019

This study develops 3D-printed-garment collections for a fashion show presentation. A design concept using traditional patterns that consisted of garments regarding the limitation of the printing technology was investigated in order to develop the collection. The structures of the connecting joints of the textile parts which could be easily and sturdily interconnected were invented. Wearability as garments that could be naturally worn on the human body were sought. As a result, four 3D-printed-garments were developed. The 1st garment composed of objects based on a 'Yeon-Dang-Cho'-pattern was constructed as a geometric robe style using a FDM 3D printer and transparent TPU filaments. The 2nd and 3rd 3D-printed-garments composed of an object based on a 'Boe-Sang-Hwa'-pattern was constructed as a distorted one-piece exaggerating the silhouettes of shoulders and waist parts as well as a straight asymmetric tunic style that used the same printer and material as the 1st garment. The last garment composed of an object based on a 'Boe-Sang-Hwa'-pattern printed using a SLA 3D printer and flexible-liquid-resin was constructed attaching the objects on the fabric material by the hot-press machine. The four developed garments were presented in the opening fashion show of 'the 6th International 3D-printing Korea Expo'. This study provides a basic case for related studies to adapt 3D-printing technology in textile pattern development of garment construction.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.251-257
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• 2020

In order to quickly and clearly recognize characters or images through display glass, glare of the glass must be suppressed. In this study, we tried to reduce glare by analyzing changes in glass surface shape and optical properties through etching process. The etching process was performed as a function of concentrations of the etching solutions, BOE and HF. During the etching process, a compound containing F ion was generated on the surface of the glass, forming an irregular pattern in the form of a projection, and thus various optical properties of the glass were changed; reflectance of 2.5~4.6 %, haze of 4.5~6.6 %, transmittance of 77~92 %, and gloss of 82~107 GU. As a result, optimum etching condition was obtained to minimize the loss of other optical properties while suppressing glare of the glass.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2099-2101
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• 2004

본 연구에서 제안하는 마이크로 시스템은 열공압 방식으로 구동되고 제작비용이 저렴한 indium tin oxide (ITO) 및 polydimethylsiloxane (PDMS)로 제작되었다. 제안된 마이크로 밸브와 마이크로 펌프의 구조는 ITO 히터, SU-8 층, PDMS membrane, 그리고 PDMS 채널로 구성 되어 있다. 제안된 마이크로 펌프와 마이크로 밸브는 제작 공정 및 구조가 간단하고 값이 저렴하며, 마이크로 펌프와 마이크로 밸브를 같은 기판 위에 쉽게 직접화할 수 있는 장점을 가진다. 마이크로 밸브의 유량은 채널 폭에 비례하며 밸브가 closing 되는 전력은 채널의 폭과 상관없이 100 mW이다. 마이크로밸브의 ITO 히터의 온-오프에 따라 유량이 매우 잘 제어되었다. 제안된 마이크로 펌프의 경우, 히터의 인가 펄스 전압이 증가함에 따라 유량은 선형적으로 비례 증가함을 관찰할 수 있다. 마이크로 펌프의 최대 유량은 펄스 전압과 duty 비가 55V와 10%일 때 6 Hz에서 78 nl/min이 측정 되었다.