• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.78-78
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• 2013

Recently, many platinoid metals like platinum and ruthenium have been used as an electrode of microelectronic devices because of their low resistivity and high work-function. However the material cost of Ru is very expensive and it usually takes long initial nucleation time on SiO2 during chemical deposition. Therefore many researchers have focused on how to enhance the initial growth rate on SiO2 surface. There are two methods to deposit Ru film with atomic layer deposition (ALD); the one is thermal ALD using dilute oxygen gas as a reactant, and the other is plasma enhanced ALD (PEALD) using NH3 plasma as a reactant. Generally, the film roughness of Ru film deposited by PEALD is smoother than that deposited by thermal ALD. However, the plasma is not favorable in the application of high aspect ratio structure. In this study, we used a bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)2] as a metal organic precursor for both thermal and plasma enhanced ALDs. In order to reduce initial nucleation time, we use several methods such as Ar plasma pre-treatment for PEALD and usage of sacrificial RuO2 under layer for thermal ALD. In case of PEALD, some of surface hydroxyls were removed from SiO2 substrate during the Ar plasma treatment. And relatively high surface nitrogen concentration after first NH3 plasma exposure step in ALD process was observed with in-situ Auger electron spectroscopy (AES). This means that surface amine filled the hydroxyl removed sites by the NH3 plasma. Surface amine played a role as a reduction site but not a nucleation site. Therefore, the precursor reduction was enhanced but the adhesion property was degraded. In case of thermal ALD, a Ru film was deposited from Ru precursors on the surface of RuO2 and the RuO2 film was reduced from RuO2/SiO2 interface to Ru during the deposition. The reduction process was controlled by oxygen partial pressure in ambient. Under high oxygen partial pressure, RuO2 was deposited on RuO2/SiO2, and under medium oxygen partial pressure, RuO2 was partially reduced and oxygen concentration in RuO2 film was decreased. Under low oxygen partial pressure, finally RuO2 was disappeared and about 3% of oxygen was remained. Usually rough surface was observed with longer initial nucleation time. However, the Ru deposited with reduction of RuO2 exhibits smooth surface and was deposited quickly because the sacrificial RuO2 has no initial nucleation time on SiO2 and played a role as a buffer layer between Ru and SiO2.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.252-271
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• 2022

This article examines the characteristics of the royal tombs of the late Silla Dynasty with the statues of the 12 animal deities(Zodiac) and estimates the process of change. The features of the statues show a difference in their combination in terms of continuity and similarity of the object in their hands. In addition, there is a difference in the shape of the face of the stone statue, and differences are observed in the orientation and aspect ratio of the statue according to the sculptural method. The characteristics of these statues are somewhat different from the previously studied protected-stone and manufacturing techniques. For example, the Zodiac statues that are flattened from high relief to low relief are known to be decorated in realistic expressions, but they tend to be treated as separate conditions because they do not match the change of the stone. In addition, there was a characteristic that did not show regular changes, such as appearing and disappearing again when there was no balustrade in the tomb. Summing up the characteristics of each part, the Zodiac statues are largely divided into curved angles and flat angles according to the sculptural technique, and the head orientation and clothing of the statue are related. They are divided into two categories and can be viewed as having temporality according to the aspect ratio. These characteristic changes are consistent with the continuity of features and changes in the object in the hands of the 12 Zodiac statues. Therefore, the number of faces with protected-stone changes were gradually increasing in trend. As a result, there is a possibility that the Gujeongdong Square-shape Tomb and King Jindeok Tomb are earlier royal tombs than the Wonseong Royal Tomb. Therefore, the royal tombs of the late Silla Dynasty have a complete, tomb structure, containing the 12 animal god statues, ceremonial spaces(拜禮空間), Shindo(神道), stone statues(石像), and tombstones. This can be understood as a basic motif for the royal tomb structures of Goryeo and Joseon.

• Membrane Journal
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• v.27 no.2
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• pp.154-166
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• 2017

Polymeric films for gas barrier applications such as food packaging and electronic devices have attracted great interest due to their cheap, light and easy processability among gas barrier materials. Especially in electronic devices, extremely low gas permeance is necessary for maintaining the device performance. However, current polymeric barrier films still suffer from relatively high gas permeance than other materials. Therefore, there have been strong needs to enhance the gas barrier performance of polymeric barrier films while keep their own advantages. Recently, graphene is highlighted as a 2D-layered material for gas barrier applications. However, owing to the poor workability and difficulty to produce in engineering scale, graphene oxide (GO) is on the rise. GO consists of oxygen-containing functional groups on surface with intrinsic 2D-layered structure and high aspect ratio, and it can be well-dispersed in aqueous polar solvents like water, resulting in scalable mass production. Here, we prepared GO incorporated polyimide (PI) nanocomposites. PI is widely used barrier polymer with high mechanical strength and thermal and chemical stability. We demonstrated that PI/GO nanocomposites could perform as a gas barrier. Furthermore, surfactants (Triton X-100 (TX) and Sodium deoxycholate (SDC)) are introduced to enhance the gas barrier performance by improving the degree of dispersion of GO in PI matrix. As a result, TX enhanced the gas barrier performance of PI/GO nanocomposites which is similar to predicted value. This finding will provide new insight to polymer nanocomposites for gas barrier applications.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.621-627
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• 2013

In order to apply eco-friendly poly(propylene carbonate) (PPC) into barrier packaging materials, six different PPC/exfoliated graphite (EFG) nanocomposite films with different EFG were successfully prepared by a solution blending method. Their water sorption behavior was gravimetrically investigated as a function of the EFG content and interpreted with respect to their chemical structure and morphology. The water sorption isotherms were reasonably well fitted by Fickian diffusion model, regardless of morphological heterogeneities. With increasing the EFG content, the diffusion coefficient and water uptake decreased from $12.5{\times}10^{-10}cm^2sec^{-1}$ to $7.2{\times}10^{-10}cm^2sec^{-1}$ and from 8.9 wt% to 4.2 wt%, respectively, which indicates that the moisture resistance capacity of PPC was greatly enhanced by incorporating EFG into PPC. The enhanced water barrier property of the PPC/EFG nanocomposite films with the high aspect ratio EFG makes them potential candidates for versatile packaging applications. However, to maximize the performance of the nanocomposite films, further researches are required to increase the compatibility of EFG in the PPC matrix.

• Design Convergence Study
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• v.16 no.3
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• pp.103-118
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• 2017

It is expected that the integrated control service of the public sector will be increased for the safety of citizens in the future. Therefore, In this study, we analyzed the classification of CCTV control center and the characteristics of interior design. The survey was conducted at eight control centers in Seoul that were constructed since 2007 and analyzed according to the criteria of general matters, services, spatial basic information, spatial structure, and internal structure. The results of the survey are summarized as follows. Based on the results of the study, the Integrated Control Center is a space where the ratio of the physical environment is not high but performs important tasks for the citizens of the city, which are operated 24 hours a day, and security and security. It is characterized by the efficient space allocation for the treatment, the design of the moving line, and the connection according to the urgent work flow. The results of this study are expected to be used as basic data for other integrated control center environment.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.43-47
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• 2016

This paper covers the study on the properties of $TiO_2$ film deposited by atomic layer deposition (ALD) using TTIP and water at various temperatures including the low temperature range of <$150^{\circ}C$. At low deposition temperature, ALD $TiO_2$ films showed uniform growth rate per cycle ($0.3{\AA}/cycle$), good uniformity, smooth surface, and homogenous amorphicity. They also showed good conformality of >80% on the trench structure with the high aspect ratio of up to 75. However, relatively high concentration of impurities (C~4-7 at%) in the film was observed due to low deposition temperature.

• Cartoon and Animation Studies
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• s.39
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• pp.321-348
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• 2015

The purpose of this study was to find a system and a progression principle in orchestral piece based on the outcome after comparatively analyzing the orchestral operation technique in "Battle for The Glory" out of the background music in the animation "Dragon Quest IV" by Koichi Sugiyama(1931~), who is a leading runner of Japan's animation music, based on functional parts daccord & Instrumentation Pattern, Rhythm Pattern, Voicing Pattern, and harmonic ratio by progression section devised by the writer. As a result, first, five themes in this music have specific instrumentation pattern, respectively. In a passage that is shown exposition, reprise, and representation in theme, the unity was emphasized by maintaining the same instrumentation pattern. On the contrary to this, a passage of being suggested new theme is being used the exchange method and addition & subtraction in musical instrument in order to strengthen diversity. Second, the voicing pattern is forming the vertical contrasting relationship of "thinness-thickness" on the whole. However, the diversity is being intensified that is changed into the structure of "thickness-thinness" in the third theme and of "thinness-thickness" that has two melodies in the fourth theme. Third, the rhythm pattern is forming the vertical contrasting relationship of "big-small" on the whole. However, the fifth theme is being given diversity with being changed into the structure of "small-big." Fourth, the harmony by progression section from the horizontal perspective is shown to be high in the proportion of unity in the section of being repeated and represented the theme and to be high in the proportion of diversity in the section of being suggested new theme. In this study, the balanced orchestral operation technique through the operation technique, which was used in this work, is what extracts the relationship of diverse proportions in the horizontal progression section based on the technique of vertical perspective. In this aspect, this analytical study is desired to be positioned as a new paradigm in establishing a theoretical system and an educational method in orchestration.

• Electrical & Electronic Materials
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• v.12 no.7
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• pp.7-11
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• 1999

Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.777-782
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• 2011

Micro features on the surface are well-known to have significant effects on optical or mechanical properties such as the optical interference, reflectance at the surface, contact angle, interfacial friction, etc. These surface micro features are increasingly employed to enhance the functionality of the applications in various application areas such as optical components for LCD or solar panel. Diverse surface features have been proposed and some of them are showing excellent efficiency or functionality, especially in optical applications. Most applications employing the micro features need manufacturing process for mass production and the injection molding and roll-to-roll forming, which are typical processes for mass production adopting polymeric materials, may be also preferred for micro patterned plastic product. Since the functionality or efficiency of the surface structures generally depends on the shape and the size of the structure itself or the array of the structures on the surface, it would be very important to replicate the features very precisely as being designed during the molding the micro pattern applications. In this paper, a series of research activities is introduced for roll-to-roll forming of micro patterned film including filling of patterns with UV curable resin, demolding of surface structures from the roll tool, control of surface energy and cure shrinkage of resin and dispose time and intensity of the UV light for curing of UV curable resin.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.59-64
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• 1992

터빈 블레이드와 같이 회전하는 구조물의 파단은 공진 근처에서 진동이 발 생할 때에 이에 기인하는 피로에 의하여 발생한다. 그러므로 이와 같은 파단 을 피하기 위해서는 설계 단계에서 이론적인 계산에 의하여 구조물의 고유 진동수를 결정하는 것이 상당히 중요하다. 판이 회전을 받게 되면 원심력에 의하여 판의 강성이 증가하므로 고유진동수가 회전하지 않는 판의 고유진동 수보다는 상당히 증가하게 된다. 이에 대한 연구가 국내외에서 상당수 행하 여졌지만, 연구의 대부분이 회전의 영향을 고려하지 않은 정지판(stationary plate)에 대한 것이며 뢰전을 고려한 연구는 극히 제한되어 있다. 또한 회전 의 영향을 고려한 연구의 대부분이 해석 대상을 보로서 단순화 시켰고 해법 으로는 유한요소법과 Ritz법 등을 사용하였다. 이는 블레이드가 지니고 있는 기하학적인 형상과 진동 특성이 해석적인 방법으로 해결하는 데에는 상당한 어려움이 있기 때문이다. 실제적으로는 터빈 블레이드와 같은 회전체의 진동 특성이 설치각이나 비틀림각, 판의 형상비, 회전속도 등의 변화에 의하여 영 향을 받기 때문에 보와 같은 진동 거동을 보이기보다는 판이나 셀과 같은 진동 거동을 보이므로 보다 정확한 해석을 수행하기 위해서는 해석 대상을 판이나 셀로서 취급하는 것이 타당하다. 따라서 본 연구에서는 위와 같은 이 유 때문에 해석 대상을 등방성 사각판과 직교이방성 복합재료 사각판으로 선택하였으며, 구조물의 고유진동수에 영향을 미치는 다음과 같은 인자들을 해석에 고려하였다. 1. 회전속도 (rotational speed) 2. 설치각 (setting angle) 3. 허브의 반경 (hub radius) 4. 판의 형상비 (aspect ratio) 5. 적층순서 (stacking sequence)구조물에 대한 동적실험(dynamic test)을 통하여 단기간에 동적특성을 결정하고 SDM(structure dynamic modification)이나 FRS(force response simulation)를 수행하여 임의의 좌표 공간에 대한 진동수준을 해석적으로 예측할 뿐만 아니라 구조물의 진동제어 를 위한 동적인자를 변경시킬 수 있는 정보를 제공하며 장비를 방진할 경우 신뢰성 있는 전달률을 결정할 수 있다. 실험적으로 철교, 교량이나 건물의 철골구조 및 2층 바닥 등 대,중형의 복잡한 구조물에 대항 동특성을 나타내 는 모빌리티를 결정할 경우 충격 가진 실험이 사용되는 실험장비 측면에서 나 실험을 수행하는 과정이 대체적으로 간편하다. 그러나 이 경우 대상 구조 물을 충분히 가진시킬수 있는 용량의 대형 충격기(large impact hammer)가 필요하게 된다. 이러한 동적실험은 약 길이 61m, 폭 16m의 4경간 교량에 대 하여 동적실험을 수행하여 가능성을 확인하였다. 여기서는 실험실 수준의 평 판모델을 제작하고 실제 현장에서 이루어질 수 있는 진동제어 구조물에 대 한 동적실험 및 FRS를 수행하는 과정과 동일하게 따름으로써 실제 발생할 수 있는 오차나 error를 실험실내의 차원에서 파악하여 진동원을 있는 구조 물에 대한 진동제어기술을 보유하고자 한다. 이용한 해마의 부피측정은 해마경화증 환자의 진단에 있어 육안적인 MR 진단이 어려운 제한된 경우에만 실제적 도움을 줄 수 있는 보조적인 방법으로 생각된다.ofile whereas relaxivity at high field is not affected by τS. On the other hand, the change in τV does not affect low field profile but stron