• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.143-143
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• 2008

Nanowires are promising options for building nanoscale electronic structures coming from high conductivity of nanowires. In particular, Deoxyribonucleic acid (DNA), which is structurally nanowire, can obtain highly ordered electronic components for nanocircuitry and/or nanodevices because of its very flexible length controllability, nanometer-size diameter, about 2 nm, and self-assembling properties. In this work, we used the method to form DNA-Nanowires (NWs) by using chemical treatment on Silicon (Si) surface, and Aminopropyl-triethoxysilane (APTES) was used as inducer of DNA sequence to modify the characteristics of Si surface. Moreover, we performed tilting technique to align DNA by the direction of flow of DNA solution. We investigated the assembly process between DNA molecules and APTES - coated Si surface according to the APTES concentration, from $1.2{\mu}\ell$ to $120{\mu}\ell$. Atomic Force Microscopy (AFM) images showed the combination rate of DNA molecules by the change of APTES concentration. As APTES concentration becomes thicker, aggregation of DNA molecules occurs, and this makes a kind of DNA networks. In this respect, we confirmed that there's a positive relationship between the concentration of APTES and the formation rate of DNA nanowires. Since there have been lots of research preceded to utilize DNA nanowires as template, so by using this positive relationship with proper alignment technique, realization of nano electronic devices with DNA nanowires might be feasible.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.4
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• pp.99-105
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• 2014

The domestic airline industry undertakes the production of finished products by assembling existing self-described components via a design process which involves assembly and production steps, after which many of the finished products are exported. However, high reliability and stability must be guaranteed, because customers require high-precision components at the time of manufacturing. In the aircraft parts industry, the mass production of high-value-added parts is limited. Therefore, a small production scale depending on the part is used, as many types of conventional CNC lathe machines with X-axis and Z-axis as well as Z-axis and C-axis CNC milling are used. The parts also rely on high-pressure air to increase production. The most important factors are good stability during processing, as high-precision parts are required, as noted above. It was found that as the C-axis rotation speed increased, the diameter of the cutting tool decreased with a decrease in the surface roughness, while the workpiece rotation speed increased with an increase in the surface roughness.

• Polymer(Korea)
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• v.29 no.6
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• pp.593-598
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• 2005

This work studied the loading capabilities and release behaviors of poly(ethylene-alt-maleic anhydride) (PEMAh)/poly(4-vinyl pyridine) (P4VP) multilayer films formed by the layer-by-layer(LbL) sequential self-assembly method, using Rodamine 6G(R6G) as an indicator. Thickness of the multilayer, and loading and subsequent release behavior of R6G from the multilayer were studied using UV-visible spectroscopy. The amount of R6G loaded in multilayer film increased linearly with increasing film thickness. pH-Sensitive permeability was observed, where lower pH environments increased both release rate and release amount. By additional assembling of PEMAh/poly(ethyleneimine) (PEI) capping layers on top of (PEMAh/P4VP)n multilayers, the release of R6G was better controlled.

• Korean Journal of Human Ecology
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• v.18 no.1
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• pp.223-236
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• 2009

The purpose of this study was to improve the sanitary management of school foodservice. A survey questionnaire was administered to 153 dietitians from elementary, middle and high schools in the Daejeon area. The questions were categorized into four fields: 'General characteristics', 'Facility and equipment set up at the schools studied', 'Performance of CCP(criticai control point)s' and 'Reasons of barriers to HACCP(hazard analysis of critical control points) implementation'. The results were as follows. Most of the subjects were the dietitians of elementary school(56.9%), were university graduates(51.0%) and were in their thirties(58.2%). The average length of their career had been 5.8 years. The average ratio of students per dietitian was 1,163. The average ratio of students per full-time employee was 124. The ratio of self-operated management was 90.2 %. The CCP7(assembling and serving) received the highest performance score, while the performance score of CCP2(management of potentially hazardous foods) was the lowest. Eighty-four percent of the surveyed school foodservices did not have pre-preparation rooms. The school foodservice operations were not well equipped with hot/cold holding equipments. Self-operated management scored higher on almost all sections(CCP1-CCP7). Contracted management scored highest on CCP8. The higher the age and career of the subject were, the higher were all the CCP performance scores. The reasons of barriers to HACCP implementation were lack of understanding of standards CCP1 and CCP2, workers' lack of cooking knowledge, and lack of information about school foodservice.

• Corrosion Science and Technology
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• v.11 no.2
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• pp.65-69
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• 2012

One dimensional(1D) $Na_2Ti_6O_{13}$ nanorods with 70 nm in diameter was synthesized by a molten salt method. Using the synthesized nanorods, about 750 nm thick $Na_2Ti_6O_{13}$ film was coated on Fluorine-doped tin oxide(FTO) glasss substrate by the Layer-by-layer self-assembly(LBL-SA) method in which a repetitive self-assembling of ions containing an opposite electric charge in an aqueous solution was utilized. Using the Kubelka-Munk function, the band gap energy of the 1D-$Na_2Ti_6O_{13}$ nanorods was nalyzed to be 3.5 eV. On the other hand, the band gap energy of the $Na_2Ti_6O_{13}$ film coated on FTO was found to be a reduced value of 2.9 eV, resulting from the nano-scale and high porosity of the film processed by LBL-SA method, which was favorable for the photo absorption capability. A significant improvement of photocurrent and onset voltage was observed with the $Na_2Ti_6O_{13}$ film incorporated into the conventional $Fe_2O_3$ photoelectrode: the photocurrent increased from 0.25 to 0.82 mA/$cm^2$, the onset voltage decreased from 0.95 to 0.78 V.

• Korean Journal of Materials Research
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• v.18 no.10
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• pp.535-541
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• 2008

Growth behavior of InGaN/GaN self-assembled quantum dots (QDs) was investigated with respect to different growth parameters in low pressure metalorganic chemical vapor deposition. Locally formed examples of three dimensional InGaN islands were confirmed from the surface observation image with increasing indium source ratio and growth time. The InGaN/GaN QDs were formed in Stranski-Krastanow (SK) growth mode by the continuous supply of metalorganic (MO) sources, whereas they were formed in the Volmer-Weber (V-W) growth mode by the periodic interruption of the MO sources. High density InGaN QDs with $1{\sim}2nm$ height and $40{\sim}50nm$ diameter were formed by the S-K growth mode. Dome shape InGaN dots with $200{\sim}400nm$ diameter were formed by the V-W growth mode. InN content in InGaN QDs was estimated to be reduced with the increase of growth temperature. A strong peak between 420-460 nm (2.96-2.70 eV) was observed for the InGaN QDs grown by S-K growth mode in photoluminescence spectrum together with the GaN buffer layer peak at 362.2 nm (3.41 eV).

• Textile Coloration and Finishing
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• v.21 no.6
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• pp.1-11
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• 2009

Super-hydrophobic surface, with a water contact angle greater than $150^{\circ}$, has a self cleaning effect termed 'lotus effect'. We introduced super-hydrophobicity onto aramid/rayon mixture fabric with dual-scale structure by assembling silica nano-sol. Mixture fabric was treated with silica nano-sol, fluoric polymer using various parameters such as particle size, concentration. Silica nano-sol size were measured using particle size analyzer. Morphological changes by particle size were observed using field emission scanning electron microscopy(FE-SEM), contact angle measurement equipment. The contact angle of water was about $134.0^{\circ}$, $137.0^{\circ}$, $143.0^{\circ}$, $139.5^{\circ}$ and $139.0^{\circ}$ for mixture fabric coated with 100.2nm, 313.7nm, 558.2nm, 628.5nm and 965.4nm silica nano-sol, compared with about $120.0^{\circ}$ for mixture fabric coated with fluoric polymer. When we mixed particle sizes of 100.2nm and 558.2nm by 7:3 volume ratio, the contact angle of water was about $146.2^{\circ}$. And we mixed particle sizes of 313.7nm and 558.2nm by 7:3 volume ratio, the contact angle of water was about $141.8^{\circ}$. Also we mixed particle sizes of 558.2nm and 965.4nm by 7:3 volume ratio, the best super-hydrophobicity was obtained. In this paper, we fabricated the water-repellent surfaces with various surface structures by using four types of silica nano-sol, and we found that the dual-scale structure was very important for the super-hydrophobicity.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.4
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• pp.1-9
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• 2010

Three-dimensional (3-D) integration is an emerging technology, which vertically stacks and interconnects multiple materials, technologies, and functional components such as processor, memory, sensors, logic, analog, and power ICs into one stacked chip to form highly integrated micro-nano systems. Since CMOS device scaling has stalled, 3D integration technology allows extending Moore's law to ever high density, higher functionality, higher performance, and more diversed materials and devices to be integrated with lower cost. The potential benefits of 3D integration can vary depending on approach; increased multifunctionality, increased performance, increased data bandwidth, reduced power, small form factor, reduced packaging volume, increased yield and reliability, flexible heterogeneous integration, and reduced overall costs. It is expected that the semiconductor industry's paradiam will be shift to a new industry-fusing technology era that will offer tremendous global opportunities for expanded use of 3D based technologies in highly integrated systems. Anticipated applications start with memory, handheld devices, and high-performance computers and extend to high-density multifunctional heterogeneous integration of IT-NT-BT systems. This paper attempts to introduce new 3D integration technologies of the chip self-assembling stacking and 3D heterogeneous opto-electronics integration for realizng the super-chip.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.3 s.40
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• pp.13-17
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• 2006

Dense and periodic arrays of holes and tungsten none dots were fabricated on silicon oxide and silicon. The holes were approximately 25 nm wide, 40 nm deep, and 60 nm apart. To obtain nano-size patterns, self-assembling resists were used to produce layer of hexagonally ordered parallel cylinders of polymethylmethacrylate(PMMA) in polystyrene(PS) matrix. The PMMA cylinders were degraded and removed with acetic acid rinse to produce a PS mask for pattern transfer. The silicon oxide was removed by fluorine-based reactive ion etching(RIE). Selectively deposited tungsten nano dots were formed inside nano-sized trench by using a low pressure chemical vapor deposition(LPCVD) method. Tungsten nano dot and trenched silicon sizes were 26 nm and 30 nm, respectively.

• 대한공업교육학회지
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• v.34 no.1
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• pp.210-237
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• 2009

The aim of this thesis is to develop a robot C programming curriculum with the subject of the students in the middle & High School and to prove the effect of the programming on creativity and programming ability. The content of the robot C programming curriculum consists of the introduction, basic knowledge and assembling of the robot (usage of kits and the theory of mechanism); the learning of the robot c programming; the assigned robot making; the original robot making, which is ultimately designed to improve the creative robot programming ability of students. The subjects are divided into two groups(38); one groups(11) taking the course of C++programming and the other(27) taking the robot C programming as well as C++programming. Then each group's improvement of creativity and programming ability is measured in both pretest and posttest. The students taking the robot C programming curriculum gain the product of the assigned robot and the original robot. Besides, it turns out that the curriculum have a meaningful effect in that students acquire the enhanced creativity according to the result of TTCT Creativity Test. Self evaluation also indicates the improvement of C++programming ability.