• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.308-309
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• 2008

We have proposed a high performance liquid crystal display using two thin film transistors (TFTs) for the large size TFT-LCD desirably 42inch WXGA panel for TVs. The device generates stronger electric fields to reorient liquid crystals than that in the conventional IPS device because the voltages with opposite polarity with respect to the common electrode are applied to each finger-type electrode. As a result, the operation voltage of 2Tr-IPS mode can be decreased and the transmittance can be increased compared to conventional IPS device. Consequently, the 2Tr-IPS has all the advantages over conventional IPS from large size point of view.

• Journal of Information Display
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• 제10권4호
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• pp.175-179
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• 2009

As the physical properties of nematic liquid crystals vary with respect to temperature, the performances of liquid crystal displays (LCDs) are highly dependent on temperature. Additionally, it is well known that the electro-optic characteristics of LCDs, such as transmittance and threshold voltage, also rely on the LCD switching modes. The temperature dependence of the electro-optic characteristics of the wide-viewing-angle LCD modes, such as in-plane switching (IPS), multidomain vertical alignment by patterned electrode (PVA), and fringe-field switching (FFS), have been studied, and the results showed that the FFS mode has lower temperature dependence compared to the IPS and PVA modes. Since the liquid crystal (LC) reorients in different ways in each mode, this result is associated with the temperature dependence of LC's bend and twist elastic constants, and also with the position of the main reorientation, either in the middle or on the surface of the LC layer.

• Applied Microscopy
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• 제40권3호
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• pp.155-162
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• 2010

뼈는 단계별 (hierarchical) 구조를 가진 복합 재료이며 독특한 구조와 기계적 특성 때문에 재료공학 분야에서 많이 연구되어져 왔다. 뼈는 주로 hydroxyapatite, 콜라겐과 물로 구성된 층판형 유 무기 재료 복합체이다. 주요 무기물로써 hydroxyapatite로 잘 알려진 calcium phosphate를 통하여 뼈는 특유의 강도를 유지하게 된다. 본 실험에서는 광학 현미경(LM)과 투과전자현미경(TEM)을 이용하여 토끼와 닭 대퇴골의 구조를 연구하였다. 구성물질 분석은 대퇴골의 calcium, potassium, oxygen 분포 변화를 알아보는데 이용하였다. 실험은 두 구조 범위에 중점을 두었다: micro scale에서 치밀골의 배열을, nano scale에서 콜라겐 섬유와 apatite 결정을 관찰하였다. Micro scale에서 닭과 토끼 대퇴골 구조의 뚜렷한 차이점이 발견되었다. Nano scale에서는 apatite 결정의 모양과 크기 그리고 콜라겐의 배열을 비교 분석하였다. 그 결과 토끼와 닭은 종이 다름에도 불구하고 nano scale에서는 화학성분과 구조가 매우 유사한 것으로 나타났다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.243-252
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• 2002

We propose a new concept: that of photonic crystal phosphors (PCPs) for display and phosphor related applications. It is well known that microcavities with dimensions comparable to the emitting wavelength strongly enhance light-matter interactions, resulting in a significant increase in spontaneous emission rate, which can be directly translated into enhancement in phosphor efficiency. In recent simulations we have demonstrated that when a microcavity is formed in a nano-phosphor structure, the luminescence band is modified, and can be made spectrally sharp and tunable by engineering the geometry/material properties of the cavity and the surrounding photonic crystal lattice. New phosphor material structures based on photonic crystals are proposed. Applications to thin film EL phosphors and particle phosphors are discussed. Additionally, economic methods of synthesizing and incorporating PCPs into current display applications are proposed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.106-107
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• 2007

We fabricated anodic aluminium oxides (AAO) on Si and sapphire substrates from the electrochemical reactions of thin AI films in an aqueous solution of oxalic acid. The thin AI films have deposited on Si and Sapphire substructure by using E-beam evaporation and thermal evaporation, respectively. The formation of AAO structures has investigated from FE-SEM measurement image and showed randomly distributed phase of nanoholes instead of the periodic lattice of photonic crystals. The AAO structure on sapphire shows the double layers of nanoholes.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.610-613
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• 2009

New rod-disc liquid crystal (LC) molecule RD12 (12 is the number of carbon atoms between the rod and disc mesogenic liquid crystals) was synthesized via the chemical attachment of six cyanobiphenly calamitic mesogens linked to the triphenyl discotic mesogen with six alkyl chain linkage. Aligning characteristics associated with homogenous alignment is investigated at first and then field-dependent molecular reorientation under a vertical electric field is studied. Interestingly, they show abnormal slow molecular transition from initiate state (no electric field condition) to certain voltage. In this condition, we observe the molecular competition during reorientation. However, once a tilting direction of disk molecules are defined, the frustration is not observed anymore. The origin of this phenomenon is explained with a suggested model for the first time.

• 분석과학
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• 제21권1호
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• pp.58-63
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• 2008

수열합성법으로 합성 제조한 TMA-A 제올라이트 내부에 이온교환법을 이용하여 나노 사이즈의 ZnO 결정을 성공적으로 담지하였다. TMA-A 제올라이트의 최적 합성 조성비로는 $Al(i-pro)_3$ : 2.2 TEOS : 2.4 TMAOH : 0.3 NaOH : 200 $H_2O$로 된 용액이었다. ZnO를 담지시킨 TMA-A 제올라이트의 합성을 위하여 0.3g의TMA-A 제올라이트와 5몰의 $ZnCl_2$ 용액을 사용하였다. ZnO 결정를 담지시킨 TMA-A 제올라이트의결정화 과정을 X-ray diffraction (XRD)를 이용하여 분석하였다. 담지된 나노 크기의 ZnO결정과 TMA-A 제올라이트의 결정성을 투과전자현미경과 고배율 투과전자현미경으로 평가하였다. 담지된 ZnO 나노 결정의 크기는 3~5 nm이었으며, 합성된 TMA-A 제올라이트의 크기는 60~100 nm 이었다. FT-IR분석으로 열처리 전 및 열처리 후 ZnO결정를 담지시킨 TMA-A 제올라이트의 결합구조를 확인하였으며, ZnO 및 TMA-A 제올라이트의 흡수 스펙트럼을 비교 평가하였다. 또한, 자외선분광기의 측정에서, ZnO결정를 담지한 TMA-A 제올라이트가 330~260 nm과 260~230 nm 두 파장의 범위에서 형광학적인 특성을 나타내었다.

• Advances in nano research
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• 제2권1호
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• pp.69-76
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• 2014

We have obtained opal-like photonic crystals based on opals and inverted opals exhibiting a shift of the selective reflection band toward longer and shorter wavelengths with respect to the diffraction band of the initial opal consisting of $SiO_2$ spheres. The contribution of frames forming three-dimensional periodic structures and that of fillers to the spectral arrangement of the diffraction bands has been determined.

• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 동계학술발표회 논문집
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• pp.155-156
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• 2006

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2007년도 학술발표회 논문집
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• pp.31-34
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• 2007

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