• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.78-80
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the Ultra Violet (UV) curable acrylate layer and MS-31 (MgO:$SiO_2$=3:1wt%) layer was adopted in organic light emitting device (OLEO) to protect organic light emitting materials from penetrations of oxygen and water vapors. The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007gm/m^{2+}day$ at $37.8^{\circ}C$ and 100% RH. This value was within the limited range of the sensitivity of WVTR measurements. And the lifetime of the HTF passivated device became almost three times longer than that of the bare device. The HTF on the OLEO was found to be very effective in protect what from the penetrations of oxygen and moisture.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.159-159
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• 1999

니켈 산화물 박막을 전자비임 증착법으로 기판온도는 RT~25$0^{\circ}C$의 범위에서 제작하였다. 제작시 초기 베이스 압력은 2$\times$10-6mbar로 하고 산소주입후 작업진공도를 3$\times$10-4mbar로 유지하여 증착하였다. 제작시 기판온도에 따라 제작된 시료들은 각각 X선회절장치(XRD)로 막의 구조과 그림과 같이 입방체 구조 또는 팔면체구조를 갖음을 알 수 있었으며 막의 표면형상은 SEM을 이용하여 분석하였다. 각각의 여러 기판온도에 따라 제작된 니켈 산화물 박막의 전기 화학적인 특성을 분석하기 위해 순환전압전류법을 이용하였다. 또한, 전기적인 광학소자로써의 특성을 분석하기 위해 UV-Vis 광분광기를 사용하여 투과율을 측정하여 그 특성을 알아보았다. 순환전압전류법에 의한 각 시료에 대한 박막의 전기화학적 특성은 0.5M KOH 전해질 수용액에서 기판온도가 150~20$0^{\circ}C$로 제작된 니켈 산화물 박막이 다른 온도에서 제작된 시료들보다 높은 전기화학적 안정성을 보임을 알 수 있었다. 마찬가지로 광학적 특성에서 착색과 탈색의 순환과정시 분광광도계에서 나타나는 광투과율을 비교해 보면 100~20$0^{\circ}C$에서 제작된 니켈 산화물 박막이 가역적인 착탈색의 색변화가 현저하게 나타남을 알 수 있었다. 결과적으로 광학적 특성 및 전기화학적 안정성 분석으로 인해 막의수명과 전기적착색 물질의 특성면에서 증착시 기판온도가 150~20$0^{\circ}C$에서 제작된 시료가 가장 내구성면에서 막의 이온 누적이 적고 활성적인 광투과율의 성질을 갖는다는 것이다. 이와같이 니켈산화물 박막제작시 기판온도가 전기적착색물질의 특성과 내구성에 큰 영향을 미침을 분석할 수 있었다.electron Microscopy)과 AFM(Atomim Force microscopy)으로 증착박 표면의 topology와 roughness를 관찰하였다. grain의 크기는 10nm에서 150nm이었고 증착막의 roughness는 4.2nm이었다. 그리고 이 산화막에 전극을 형성하여 유전 상수와 손실률 등을 측정하였다. 이와 같이 plasma를 이용한 3-beam에 의한 증착은 금속의 산화막을 얻는데 유용한 기술로 광학 재료 및 유전 재료의 개발 및 연구에 많이 사용될 것으로 기대된다.소분압 조건에서 RuO2의 형성을 관찰하였으며, 이것은 열역학적인 계산을 통해서 잘 설명할 수 있었다.0$\mu\textrm{m}$, 코일간의 간격은 100$\mu\textrm{m}$였다. 제조된 박막 인덕터는 5MHz에서 1.0$\mu$H의 인덕턴스를 나타내었으며 dc current dervability는 100mA까지 유지되었다. CeO2 박막과 Si 사이의 결함때문이라고 사료된다.phology 관찰결과 Ge 함량이 높은 박막의 입계가 다결정 Si의 입계에 비해 훨씬 큰 것으로 나타났으며 근 값도 증가하는 것으로 나타났다. 포유동물 세포에 유전자 발현벡터로써 사용할 수 있음으로 post-genomics시대에 다양한 종류의 단백질 기능연구에 맡은 도움이 되리라 기대한다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상 분사기술의 최적

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.619-619
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• 2009

Recently, silica nanostructures are widely used in various applicationary areas such as chemical sensors, biosensors, nano-fillers, markers, catalysts, and as a substrate for quantum dots etc, because of their excellent physical, chemical and optical properties. Additionally, these days, semiconductor silica and silicon with high purity is a key challenge because of their metallurgical grade silicon (MG-Si) exhibit purity of about 99% produced by an arc discharge method with high cast. Tremendous efforts are being paid towards this direction to reduce the cast of high purity silicon for generation of photovoltaic power as a solar cell. In this direction, which contains a small amount of impurities, which can be further purified by acid leaching process. In this regard, initially the low cast rice-husk was cultivated from local rice field and washed well with high purity distilled water and were treated with acid leaching process (1:10 HCl and $H_2O$) to remove the atmospheric dirt and impurity. The acid treated rice-husk was again washed with distilled water and dried in an oven at $60^{\circ}C$. The dried rice-husk was further annealed at different temperatures (620 and $900^{\circ}C$) for the formation of silica nanospheres. The confirmation of silica was observed by the X-ray diffraction pattern and X-ray photoelectron spectroscopy. The morphology of obtained nanostructures were analyzed via Field-emission scanning electron microscope(FE-SEM) and Transmission electron microscopy(TEM) and it reveals that the size of each nanosphares is about 50-60nm. Using the Inductively coupled plasma mass spectrometry(ICP-MS), Silica was analyzed for the amount of impurities.

• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.277-284
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• 2013

Carbon coils could be synthesized using $C_2H_2/H_2$ as source gases and $SF_6$ as an incorporated additive gas under thermal chemical vapor deposition system. The Ni layer on the $SiO_2$ substrate was used as a catalyst for the formation of the carbon coils. The characteristics (formation densities, morphologies, and geometries) of the as-grown carbon coils on the substrate with or without the $H_2$ plasma pretreatment process were investigated. By the relatively short time (1 minute) $H_2$ plasma pretreatment on the Ni catalyst layered-substrate prior to the carbon coils synthesis reaction, the dominant formation of the carbon microcoils on the substrate could be achieved. After the relatively long time (30 minutes) $H_2$ plasma pretreatment process, on the other hand, we could obtain the noble-shaped geometrical nanostructures, namely the formation of the numerous carbon nanocoils along the growth of the carbon microcoils. This noble-shaped geometrical nanostructure seemed to play a promising role as the good catalyst support for holding the very tiny Ni catalyst grains.

• Journal of the Korean Electrochemical Society
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• v.13 no.2
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• pp.145-152
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• 2010

The gel polymer electrolyte(GPE) were prepared by in-situ thermal cross-linking reaction of homogeneous precursor solution of perfluorinated phosphate-based cross-linker and liquid electrolyte. Ionic conductivities and electrochemical properties of the prepared gel polymer electrolyte with the various contents of liquid electrolytes and perfluorinated organophosphate-based cross-linker were examined. The stable gel polymer electrolyte was obtained up to 97 wt% of the liquid electrolyte. Ionic conductivity and electrochemical properties of the gel polymer electrolytes with the various chain length of perfluorinated ethylene oxide and different content of liquid electrolytes were examined. The maximum ionic conductivity of liquid electrolyte was measured to be $1.02\;{\times}\;10^{-2}\;S/cm$ at $30^{\circ}C$ using the cross-linker($PFT_nGA$). The electrochemical stability of the gel polymer electrolyte was extended to 4.5 V. The electrochemical performances of test cells composed of the resulting gel polymer electrolyte were also studied to evaluate the applicability on the lithium polymer batteries. The test cell carried a discharge capacity of 136.11mAh/g at 0.1C. The discharge capacity was measured to be 91% at 2C rate. The discharge capacity decreased with increase of discharge rate which was due to the polarization. After 500th charge/discharge cycles, the capacity of battery decreased to be 70% of the initial capacity.

• Journal of Adhesion and Interface
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• v.20 no.3
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• pp.102-109
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• 2019

The material constitution of multi-layered thin film coated on the PET base film was analyzed using ATR FT-IR and pyro GC/MS combination. The cross section of the film was acquired by cracking the film after dipping in liquid nitrogen and was observed using optical microscope. Total thickness of the coated film was $70{\mu}m$ and three layers were observed. Since each layers were too thin to analyze directly except the surface layer, analyzable area of each layers were exposed by using a proper solvent and were investigated using ATR FT-IR and pyro GC/MS. Results shows that three layers were commonly consisted of urethane-acrylate copolymers. Also, inorganic and/or metal inclusions detected by XPS and SEM-EDAX were exhibited by nano size $SiO_2$ particles in layer(1) and aluminum flakes in layer(2).

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.156-156
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• 2000

Recently, the surface electronic states have attracted much attention since their standing wave patterns created around steps, defects, and adsorbates on noble metal surfaces such as Au(111), Ag(110), and Cu(111) were observed by scanning tunneling microscopy (STM). As a typical example, a striking circular pattern of "Quantum corral" observed by Crommie, Lutz, and Eigler, covers a number of text books of quantum mechanics, demonstrating a wavy nature of electrons. After the discoveries, similar standing waves patterns have been observed on other metal and demiconductor surfaces and even on a side polane of nano-tubes. With an expectation that the surface states could be utilized as one of ideal cases for studying two dimensionakl (sD) electronic system, various properties, such as mean free path / life time of the electronic states, have been characterized based on an analysis of standing wave patterns, . for the 2D electron system, electron density is one of the most importnat parameters which determines the properties on it. One advantage of conventional 2D electron system, such as the ones realized at AlGaAs/GaAs and SiO2/Si interfaces, is their controllability of the electrondensity. It can be changed and controlled by a factor of orders through an application of voltage on the gate electrode. On the other hand, changing the leectron density of the surface-state 2D electron system is not simple. On ewqy to change the electron density of the surface-state 2D electron system is not simple. One way to change the electron density is to deposit other elements on the system. it has been known that Pd(111) surface has unoccupied surface states whose energy level is just above Fermi level. Recently, we found that by depositing Pd on Cu(111) surface, occupied surface states of Cu(111) is lifted up, crossing at Fermi level around 2ML, and approaches to the intrinsic Pd surface states with a increase in thickness. Electron density occupied in the states is thus gradually reduced by Pd deposition. Park et al. also observed a change in Fermi wave number of the surface states of Cu(111) by deposition of Xe layer on it, which suggests another possible way of changing electron density. In this talk, after a brief review of recent progress in a study of standing weaves by STM, I will discuss about how the electron density can be changed and controlled and feasibility of using the surface states for a study of 2D electron system. One of the most important advantage of the surface-state 2D electron system is that one can directly and easily access to the system with a high spatial resolution by STM/AFM.y STM/AFM.

• Ultrasonography
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• v.32 no.1
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• pp.59-65
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• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1090-1096
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• 2005

$Ag_4Br_4$ nanoclusters have been synthesized in about 75% of the sodalite cavities of fully $K^+$-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar $K_4Br^{3+}$ cation. A single crystal of $Ag_{12}$-A, prepared by the dynamic ion-exchange of $Na_{12}$-A with aqueous 0.05 M $AgNO_3$ and washed with $CH_3OH$, was placed in a stream of flowing 0.05 M KBr in $CH_3OH$ for two days. The crystal structure of the product ($K_9(K_4Br)Si_{12}Al_{12}O_{48}{\cdot}0.75Ag_4Br_4$, a = 12.186(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index $R_1$ = 0.080 for the 99 reflections for which $F_o\;{\gt}\;4_{\sigma}\;(F_o)$. The thirteen $K^+$ ions per unit cell are found at three crystallographically distinct positions: eight $K^+$ ions in the large cavity fill the six-ring site, three $K^+$ ions fill the eight-rings, and two $K^+$ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring $K^+$ ions ($K_4Br^{3+}$). Three $Ag^+$ and three $Br^-$ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized $Ag_4Br_4$ clusters (interpenetrating tetrahedra; symmetry $T_d$; diameter ca. 7.9 $\AA$) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) $\AA$) is held in place by the coordination of its four $Ag^+$ ions to the zeolite framework (each $Ag^+$ cation is 2.52(3) $\AA$ from three six-ring oxygens) and by the coordination of its four $Br^-$ ions to $K^+$ ions through six-rings (Br-K = 3.00(4) $\AA$).

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.187-187
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• 2012

In this report, the plasmonic nanopores of less than 5 nm diameter were fabricated on the apex of the pyramidal cavity array. The metallic pyramidal pit cavity can also utilized as the plasmonic bioreactor, and the fabricated Au or Al metallic nanopore can provide the controllable translocation speed down using the plasmonic optical force. Initially, the SiO2 nanopore on the pyramidal pit cavity were fabricated using conventional microfabrication techniques. Then, the metallic thin film was sputter-deposited, followed by surface modification of the nanometer thick membrane using FESEM, TEM and EPMA. The huge electron intensity of FESEM with ~microsecond scan speed can provide the rapid solid phase surface transformation. However, the moderate electron beam intensity from the normal TEM without high speed scanning can only provide the liquid phase surface modification. After metal deposition, the 100 nm diameter aperture using FIB beam drilling was obtained in order to obtain the uniform nano-aperture. Then, the nanometer size aperture was reduced down to ~50 nm using electron beam surface modification using high speed scanning FESEM. The followed EPMA electron beam exposure without high speed scanning presents the reduction of the nanosize aperture down to 10 nm. During these processes, the widening or the shrinking of the nanometer pore was observed depending upon the electron beam intensity. Finally, using 200 keV TEM, the diameter of the nanopore was successively down from 10 nm down to 1.5 nm.