• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.525-529
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• 2018

The antireflective (AR) coated poly methyl methacrylate (PMMA) substrate was deposited by atomic layer deposition (ALD) on a self-assembled monolayer (SAM) to improve hydrophobicity and mechano-chemical properties of organic thin films. The water contact angles (WCA) were tested to characterize the surface wettability of SAM octadecyltrichlorosilane (OTS) films. Results showed that a contact angle of $105.9^{\circ}$ was obtained for the SAM films with an annealing process, and the highest WCA of $120^{\circ}$ was achieved for the films prepared by the SAM and ALD multi-process. The surface morphology of the SAM films with different assembly times and varying number of ALD cycles was obtained by atomic force microscopy (AFM). The maximum light transmittance for the SAM films on the PMMA substrate reached 99.9% at a wavelength of 450 nm. It was found that the SAM surfaces were not affected at all by the ALD process.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.417-428
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• 2018

In this study, we fabricated hierarchically self-assembled thin films composed of graphene oxide (GO) sheets and gold nanoparticles (Au NPs) using the Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) techniques and investigated their gas-sensing performance. First, a thermally oxidized silicon wafer ($Si/SiO_2$) was hydrophobized by depositing the LB films of cadmium arachidate. Thin films of ligand-capped Au NPs and GO sheets of the appropriate size were then sequentially transferred onto the hydrophobic silicon wafer using the LB and the LS techniques, respectively. Several different films were prepared by varying the ligand type, film composition, and surface pressure of the spread monolayer at the air/water interface. Their structures were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their gas-sensing performance for $NH_3$ and $CO_2$ was assessed. The thin films of dodecanethiol-capped Au NPs and medium-sized GO sheets had a better hierarchical structure with higher uniformity and exhibited better gas-sensing performance.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.189-189
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• 2015

Plasmonics, sensor, field effect transistors, solar cells 등 다양한 적용분야를 가지는 실리콘 구조체는 제작공정에 의해 전기적 및 광학적 특성이 달라지기 때문에 적합한 나노구조 제작방법이 요구되고 있다. 나노구조체 제작방법으로는 Photo lithography, Extreme ultraviolet lithography (EUV), Nano imprinting lithography (NIL), Block copolymer (BCP) 방식의 방법들이 연구되고 있으며, 특히 BCP는 direct self-assembly 특성을 가지고 있으며 가격적인 면에서도 큰 장점을 가진다. 하지만 BCP를 mask로 사용하여 식각공정을 진행할 경우 BCP가 버티지 못하고 변형되어 mask로서의 역할을 하지 못한다. 이러한 문제를 해결하기 위하여 본 논문에서는 BCP와 질화막을 이용한 double mask 방법을 사용하였다. 기판 위에 BCP를 self-assembly 시키고 mask로 사용하여 hole 부분으로 노출된 기판을 Ion gun을 통해 질화 시킨 후에 BCP를 제거한다. 기판 위에 hole 모양의 질화막 표면은 BCP와 다르게 etching 공정 중 변형되지 않는다. 이러한 질화막 표면을 mask로 사용하여 pillar pattern의 실리콘 나노구조체를 제작하였다. 질화막 mask로 사용되는 template은 PS와 PMMA로 구성된 BCP를 사용하였다. 140kg/mol의 polystyrene과 65kg/mol의 PMMA를 톨루엔으로 용해시키고 실리콘 표면 위에 spin coating으로 도포하였다. Spin coat 후 230도에서 40시간 동안 열처리를 진행하여 40nm의 직경을 가진 PS-b-PMMA self-assembled hole morphology를 형성하였다. 질화막 형성 및 etching을 위한 장비로 low-energy Ion beam system을 사용하였다. Reactive Ion beam은 ICP와 3-grid system으로 구성된 Ion gun으로부터 형성된다. Ion gun에 13.56 MHz의 frequency를 갖는 200W 전력을 인가하였다. Plasma로부터 나오는 Ion은 $2{\Phi}$의 직경의 hole을 가지는 3-grid hole로 추출된다. 10~70 voltage 범위의 전위를 plasma source 바로 아래의 1st gird에 인가하고, 플럭스 조절을 위해 -150V의 전위를 2nd grid에 인가한다. 그리고 3rd grid는 접지를 시켰다. chamber내의 질화 및 식각가스 공급은 2mTorr로 유지시켰다. 그리고 기판의 온도는 냉각칠러를 이용하여 -20도로 냉각을 진행하였다. 이와 같은 공정 결과로 100 nm 이상의 높이를 갖는 40 nm직경의 균일한 Silicon pillar pattern을 형성 할 수 있었다.

• 한국콘텐츠학회논문지
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• 제20권8호
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• pp.559-571
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• 2020

본 연구는 국회사무처 등 의정지원조직에서 개인-환경 적합성이 직무수행에 미치는 영향을 분석할 목적으로 수행되었다. 이러한 목적을 수행하기 위해 의정지원조직 공무원을 대상으로 설문조사를 실시하였고, 개인-환경 적합성(유사적합성, 보완적합성), 직무수행(과업수행, 맥락수행, 적응수행) 자기효능감을 변수로 설정하여 각각에 대한 영향요인을 구조방정식 모형 분석을 통해 규명하였다. 분석 결과 의정지원조직 공무원들의 유사 적합성은 과업수행, 맥락수행, 적응수행에서 모두 긍정적 영향을 미치는 것으로 확인되었다. 그러나 보완적합성은 과업수행, 맥락수행, 적응수행 모두에 직접적으로 영향을 미치지 않고 자기효능감을 매개로 직무수행에 영향을 미치는 것으로 나타났다. 본 연구 결과의 시사점은 의정지원조직 공무원의 직무수행도를 제고하기 위해서는 조직구성원과 직무와의 일치도를 높이는 것이 중요하다는 것을 확인해주는 한편 전공, 경력 등을 통한 부서배치 전략만으로는 성공적인 직무수행을 담보할 수 없으며 별도로 자기효능감 향상을 위한 관리가 필요하다는 것이다. 또한 본 연구에서는 의정지원조직의 교육훈련 과정에 자기효능감과 관련한 교육훈련 프로그램 도입 필요성을 제안하였다.

• 한국재료학회지
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• 제23권8호
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• pp.453-461
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• 2013

Controlling the stick and slip motions of the contact lines in a confined geometry comprised of a spherical lens with a flat substrate is useful for manufacturing polymer ring patterns. We used a sphere on a flat geometry, by which we could control the interfaces of the solution, vapor and substrate. By this method, hundreds of concentric ring-pattern formations of a linear conjugated polymer, poly [2-methoxy-5-(2-thylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), were generated with excellent regularity over large areas after complete solvent evaporation. Subsequently, the MEH-PPV ring patterns played a role as a directed template to organize highly regular concentric rings of single-walled carbon nanotubes(SWCNTs); when a droplet of the SWCNT suspension in water was casted onto the prepared substrate, hydrophobic polymer patterns confined the water dispersed SWCNTs in between the hydrophilicized $SiO_2/Si$ substrate. As the solvent evaporated, SWCNT-rings were formed in between MEH-PPV rings with controlled density. Finally, we used a lift-off process to produce SWCNT patterns by the removal of a sacrificial polymer template with organic solvent. We also fabricated a field effect transistor using self-assembled SWCNT networks on a $SiO_2/Si$ substrate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.452-455
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• 2004

In this paper, investigations of the SAMs(self-assembled monolayers) of a thiol-fuctionalized viologen derivatives, $V_8SH$ and $SH_8V_8SH$, where, V is N,N'-dialkylbipyridinium (i.e. a viologen group), have been carried out by elucidate voltammetry date. The redox reactions are highly reversible and can be cycled many times without significant side reaction, which has been known as a nano-gram order mass detector through resonant frequency change self-assembly process of the viologen has been investigated with $QCM({\Delta}F)$. The assembling process of the $V_8SH$ and $SH_8V_8SH$ monolayers can be finished completely in about 1 hour. The measured frequency shift for $V_8SH$ and $SH_8V_8SH$ were about 351 and 172 Hz, respectively. From these values, we calculated that the mass adsorbed $V_8SH$ and $SH_8V_8SH$ were about 375 and 183 ng. We believe that this mass loss is caused by the simultaneous loss of the anions present within the monolayer for charge compensation of the viologen dications and some solvent.

• Nuclear Engineering and Technology
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• 제41권4호
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• pp.493-520
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• 2009

During the last four decades, 16 Pressurized Water Reactors (PWR) and 4 Pressurized Heavy Water Reactors (PHWR) have been constructed and operated in Korea, and nuclear fuel technology has been developed to a self-reliant state. At first, the PWR fuel design and manufacturing technology was acquired through international cooperation with a foreign partner. Then, the PWR fuel R&D by Korea Atomic Energy Research Institute (KAERI) has improved fuel technology to a self-reliant state in terms of fuel elements, which includes a new cladding material, a large-grained $UO_2$ pellet, a high performance spacer grid, a fuel rod performance code, and fuel assembly test facility. The MOX fuel performance analysis code was developed and validated using the in-reactor test data. MOX fuel test rods were fabricated and their irradiation test was completed by an international program. At the same time, the PWR fuel development by Korea Nuclear Fuel (KNF) has produced new fuel assemblies such as PLUS7 and ACE7. During this process, the design and test technology of fuel assemblies was developed to a self-reliant state. The PHWR fuel manufacturing technology was developed and manufacturing facility was set up by KAERI, independently from the foreign technology. Then, the advanced PHWR fuel, CANFLEX(CANDU Flexible Fuelling), was developed, and an irradiation test was completed in a PHWR. The development of the CANFLEX fuel included a new design of fuel rods and bundles.. The nuclear fuel technology in Korea has been steadily developed in many national R&D programs, and this advanced fuel technology is expected to contribute to a worldwide nuclear renaissance that can create solutions to global warming.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1135-1140
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• 2012

An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.

• 폴리머
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• 제26권5호
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• pp.634-643
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• 2002

고분자 주사슬에 벤젠과 sulfonyloxvimide moiety를 가지고 있는 polyamic acid 초박막을 LB 기법을 이용하여 제조한 다음 200 $^{\circ}C$에서 1시간 동안 열처리에 의해 감광성 폴리이미드 LB 필름을 얻었다. Polyamic acid는 THF-pyridine 공용매를 가지고 축중합에 의해 합성하였다. 모든 단량체와 고분자는 원소분석, FT-IR, $^1$H-NMR의 분광학적 측정을 통해 정량 정성분석을 행하였다. UV lithography 방법을 사용하여 금 기판 위에 제조한 감광성 폴리이미드 LB 필름의 마이크로 어레이 패턴을 제조하였다. 형성된 마이크로 어레이 패턴을 따라 두 가지의 자기조립 방법으로 단백질 cytochrome c 단분자 막을 고정화시켰다. 자기조립된 cytochrome c 단분자 막의 물리ㆍ전기 화학적 특성은 cyclic voltammetry와 AFM을 통해 조사하였으며 생물전자소자로의 응용 가능성에 대해서도 검토하였다.

• 인간식물환경학회지
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• 제24권3호
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• pp.277-283
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• 2021

Background and objective: This study was conducted to increase understanding of agriculture through agricultural experience programs for adolescents living in self-reliance residence hall, and to investigate changes in work performance ability through changes in hand function. Methods: There were 11 subjects, and the average age was 18.2 years, all males without disabilities. The agricultural experience program consists of a total of 10 sessions including orientation and watching videos on future agriculture, creating vegetable gardens, planting, managing each crop, harvesting, visiting the processing room, and selling at a local food store. Results: The change in agricultural literacy by the agricultural experience program positively improved from a score of 113.73 to 127.91 (p = .008). The changes by sub-item are as follows. The value and safety of agri-foods (p = .020) and agriculture and natural environment (p = .007) were significantly improved. The function and value of rural areas (p = .050), production of agricultural products (p = .160), processing and distribution of agricultural products (p = .248), and agricultural policies (p = .058) were not significantly changed. The simple function of the hands was measured by the number of pegs inserted during 30 seconds, and the assembly function was measured by the number of pegs inserted during 60 seconds. In the case of simple function, the dominant hand was improved from 14.82 to 15.83 (p = .014), andthe non-dominant hand was also significantly improved from 13.79 to 15.01 (p = .002). There was no significant improvement in the simple function (p = .153) and assembly function (p = .770) of both hands. Conclusion: It is considered that the agricultural experience program will enable youths living in self-reliance residence halls to enhance their understanding of agriculture as an occupation, and enable them to play a role as wise consumers by positively affecting improvements in their agricultural literacy and simple hand functions.