• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2006년도 제33회 추계학술대회 발표논문집
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• pp.73-73
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• 2006

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1933-1935
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• 2002

In this paper, we present a study of the structure and electro-optic behavior of hybrid liquid-crystal-silica sphere composite photonic crystals, formed by filling the (26% by volume) void space of fee (face centered cubic) silica opals infiltrated with a nematic liquid crystal. Three dimensional photonic crystals of visible range were fabricated via a self assembly method of silica spheres of submicron diameter. The expected fee structure was confirmed by scanning electron microscopy (SEM) of the dehydrated crystal with glass removed. The photonic crystal exhibited significant electric-field-induced shift of the optical Bragg reflection peak when the liquid crystal has the long molecular axis oriented parallel to the sphere surfaces.

• 한국진공학회지
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• 제2권2호
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• pp.145-151
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• 1993

본 연구에서는 표면 분석 장비에 필요한 초고진공 용기를 설계 제작하였으며, LEED optics를 이용한 AES와 LEED 제어 장비를 설계하여 제작하였다. 제작된 일련의 장비들을 이용하여 LEED optics의 전자에너지 분해능을 측정하고, Pt(111) 표면에 증착된 Ni의 성장양식을 단분자층과 단분자층의 형성모델을 가정하여 증착된 Ni의 두께를 Auger signal의 비로부터 구하였다.

• 한국재료학회지
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• 제22권7호
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• pp.379-383
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• 2012

$TiO_2$ thin films consisting of positively charged poly(diallyldimethylammonium chloride)(PDDA) and negatively charged titanium(IV) bis(ammonium lactato) dihydroxide(TALH) were successfully fabricated on glass beads by a layer-by-layer(LBL) self-assembly method. The glass beads used here showed a positive charge in an acid range and negative charge in an alkaline range. The glass beads coated with the coating sequence of(PDDA/TALH)n showed a change in the surface morphology as a function of the number of bilayers. When the number of bilayers(n) of the(PDDA/TALH) thin film was 20, Ti element was observed on the surface of the coated glass beads. The thin films coated onto the glass beads had a main peak of the (101) crystal face and were highly crystallized with XRD diffraction peaks of anatase-type $TiO_2$ according to an XRD analysis. In addition, the $TiO_2$ thin films showed photocatalytic properties such that they could decompose a methyl orange solution under illumination with UV light. As the number of bilayers of the(PDDA/TALH) thin film increased, the photocatalytic property of the $TiO_2$-coated glass beads increased with the increase in the thin film thickness. The surface morphologies and optical properties of glass beads coated with $TiO_2$ thin films with different coating numbers were measured by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD) and by UV-Vis spectrophotometry(UV-vis).

• Applied Microscopy
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• 제42권2호
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• pp.77-86
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• 2012

배회성거미류인 광릉늑대거미(Arctosa kwangreungensis)를 실험재료로 배후발생에 따른 거미 중추신경계의 형태적 분화와 그 조직학적 변화를 관찰하였다. 식도를 중심으로 위쪽의 식도상신경절과 아래쪽의 식도하신경절이 서로 연결된 구조를 지닌 광릉늑대거미의 중추신경계는 부화가 이루어지는 후기배아 시기 이전에 확립되었고, 전대뇌(protocerebrum) 영역도 구분되었다. 후기배아 단계에서는 시각정보를 수용하는 시엽(optic lobe)의 발달이 미진하였으나 알주머니를 벗어나 본격적인 먹이활동을 시작하는 제2령 시기를 전후하여 성체와 동일한 신경계의 체제가 구축되었다. 후기배아 시기에 관찰된 식도상신경절의 미분화 세포들로부터 시각기 신경절이 발생되었고, 식도하신경절에서는 네 쌍의 부속지 신경절과 복부 신경절이 분화되었다. 또한, 발생 중인 유충의 중추신경계에서는 조직학적 특성이 다른 세 유형의 신경세포들이 관찰되었고, 발생단계에 따라 이들 세포집단의 이동과 분포상의 차이가 확인되었다.

• 한국결정성장학회지
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• 제29권4호
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• pp.143-148
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• 2019

우리는 분자선 에피택시(Molecular Beam Epitaxy) 법을 사용하여 광전기화학적 물분해 수소생산용 고종횡비 GaN 기반 나노와이어를 Si 기판 위에 성공적으로 제작하였다. 주사전자현미경(SEM)과 에너지분산형 분광법(EDX)은 p-GaN:Mg 및 p-InGaN 나노와이어가 고밀도와 함께 수직으로 성장 되었음을 증명하였다. 또한, p-InGaN 나노와이어의 발광 파장을 552 nm에서 590 nm까지의 조절이 가능하다는 것을 확인하였다. 이렇게 제작된 p-InGaN 나노와이어는 태양광을 통해 외부 전위 없이 물분해가 가능한 수소생산용 광촉매로써 매우 유용하게 사용될 수 있다.

• 한국레이저가공학회지
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• 제8권1호
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• pp.27-37
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• 2005

During laser spot welding of the braun tube electron gun, phenomena such as serious spattering and oxidative reaction, etc. were occurred. The spatter occurred from weld pool affects the braun tube, namely it blocks up a very small hole on the shadow mask and causes short circuit between two poles of the electron gun. We guessed that high power density and oxidative reaction are main sources of these problems. So, we studied to prevent and to reduce spatter occurring in spot welding of the braun tube electron gun using pulsed Nd:YAG laser. The characteristics of laser output power was estimated, and the loss of laser energy by optical parameter and spatter was measured by powermeter. The effects of welding parameters, laser defocused distance and incident angle, were investigated on the shape and penetration depth of the laser welded bead in flare and flange joints. From these results, the laser peak power was a major factor to control penetration depth and to occur spatter. It was found that the losses of laser energy by optic parameter and sticked spatter affect seriously laser weldability of thin sheets.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 광학 및 양자전자학 워크샵
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• pp.5-8
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• 1991

New nonliner organic materials have been developed for all-optical signal processing. The organic materials possess many interesting features for this purpose. Unlike inorganic molecules the delocalized $\pi$-electron distribution and intramolecular charge transfer mevhanism allows certain organic molecules to respond highly anharmonically to an external field. In the present paper the origins of nonlinear phenomena, advantages of orgnic materials and structures of organic devices will be discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.377-380
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• 2008

In this work, we measured the spatiotemporal surface charge distribution by the longitudinal electro-optic amplitude modulation method with BSO single crystal to investigate the decay and diffusion characteristics of surface charges in three types of MgO. The speed of decay and diffusion of two different kinds doped MgO is compared with those of pure MgO. The difference in the characteristics of the decay and diffusion between the electron and ion surface charges is investigated separately. We found that the rate of ion decay is the major factor that makes the difference of the temporal variation of wall voltage among different types doped MgO.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 하계학술발표회 논문집
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• pp.329-330
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• 2007

Today some many types of 3D display are developed but that are not possibly multiviewer, multiview and full parallax. Our new research work uses the Quantum optic to develop 3D display. Quantum mechanically, we can think of the first photon making a virtual transition to the second state. If the second photon appears within the lifetime of that state, the absorption sequence to the third level can be completed. When the electron, located in the third state, shifts to the first state, that electron emits one visible photon. We controlled the two invisible lights to draw a pixel in volume.