• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.37.2-37.2
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• 2004

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.96.2-96
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• 2003

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.109-116
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• 2003

Amorphous GaN Quantum dots(a-GaN QDs) with particle diameters less than bohr radius(~11nm) were successfully fabricated at room temperature by a laser ablation of high densified GaN target. Transmission electron microscopy, SAED diffraction pattern and X-ray photoelectron spectroscopy confirmed the presence of a-GaN QDs with particle size of 7.9, 6.9, 4.4nm under the Ar gas pressures of 50, 100 and 200 Pa, respectively. The room temperature PL and absorbance spectra showed a strong band emission centered at 3.9 eV in a-GaN QDs made under the gas pressures of 100 and 200 Pa, which is nearly 0.5eV blueshifted with respect to the bulk crystal band gap.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.1
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• pp.33-36
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• 2004

Amorphous GaN film was deposited using a laser ablation of the highly densified GaN target. Through the surface morphological and compositional analysis of films deposited under various laser energies and Ar gas pressures, the film deposited under the pressure of 10 Pa were found to be amorphous GaN with the smooth surface. In particular, the film at 200 mJ/pulse showed the enhanced crystallinity and stoichiometric composition, compared with those of the films at relatively lower laser energy. The strong band-gap emission at 2.8 eV was observed from amorphous GaN film in the room temperature photoluminescence spectra, showing the highest efficiency in the film at 200 mJ/pulse under 10 Pa.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1638-1642
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• 2010

Mesoporous carbon CMK-3s with different textural properties have been used for the adsorption of phenol to understand the necessary physicochemical properties of carbon for the efficient removal of phenol from contaminated water. The kinetic constants (both pseudo-second order and pseudo-first-order kinetics) increase with increasing pore size of carbons. The maximum adsorption capacities correlate well with micropore volume compared with surface area or total pore volume even though large pore (meso or macropore) may contribute partly to the adsorption. The pore occupancies also explain the importance of micropore for the phenol adsorption. For efficient removal of phenol, carbon adsorbents should have large micropore volume and wide pore size for high uptake and rapid adsorption, respectively.

• Applied Microscopy
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• v.51
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• pp.1.1-1.2
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• 2021

We demonstrate a fabrication of an atomically controlled single-crystal heart-shaped nanostructure using a convergent electron beam in a scanning transmission electron microscope. The delicately controlled e-beam enable epitaxial crystallization of perovskite oxide LaAlO₃ grown out of the relative conductive interface (i.e. 2 dimensional electron gas) between amorphous LaAlO₃/crystalline SrTiO₃.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.861-864
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• 2004

본 연구에서는 Ta이 도핑된 $TiO_2$와 $Au/TiO_2$ nanocomposite 박막을 co-sputtering법으로 제작하였다. Ta-doped $TiO_2$ 박막은 금흥석(rutile)에서 아나타제 상으로 변하는 구조를 유도하는 고용체를 형성했다. $Au/TiO_2$ nanocomposite film의 경우에는, 지름이 약 15 nm인 Au particles들이 $TiO_2$ matrix에 균질하게 분포되었다. Ta가 도핑된 $TiO_2$ 전극과 $Au/TiO_2$ 나노 콤포사이트 전극의 anodic photocurrents가 UV뿐만 아니라 가시광선 영역에서도 관찰되었다. Ta이 도핑된 $TiO_2$ 전극과 $Au/TiO_2$ 나노 콤포사이트 사이의 가시광선 영역에서 photoresponse는 계면 상태로 부터의 bandgap의 감소와 전자의 photoexcitation 때문이다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.2
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• pp.79-82
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• 2003

GaN nanoparticles were synthesized by the pulsed laser deposition (PLD) process on $SiO_2$substrate after irradiating the surface of the GaN sintered pellet by the ArF (193 nm) excimer laser. At this moment Ar gas pressure of 100 Pa, 50 Pa, 10 Pa and 1 Pa were applied during the ablation process and laser power of 100 mJ and 200 mJ were also applied. The synthesized fan nanoparticles were characterized by XRD, SEM, TEM, XPS and optical absorption spectra. The synthesized GaN nanoparticles had the crystallite sizes of 20~30 nm, and besides, GaN nanoparticles synthesized under low Ar gas pressure compared to the others corresponded with stoichiometry, and the optical band edge of the GaN nanoparticles was blueshifted.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.63-68
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• 2004

Sugar-based gelator p-dodecanoyl-aminophenyl- ${\beta}$-D-aldopyranosides (1-3) have been shown to self-assemble in the presence of p-aminophenyl aldopyranosides. The hydrogel 1+4 showed the double-helical structure with 3-25 nm outer diameters, which is quite different from that of 1. The gel 2+5 revealed twisted ribbon structure with 30-50 nm in widths and a few micrometers of length whereas the gel 3+4 revealed the single and the bundled fiber structures. The difference in these gel supramolecular structures has successfully been transcribed into silica structures by sol-gel polymerization of tetraethoxysilane (TEOS), resulting in the doublehelical, the twisted-ribbon, the single and the multiple (lotus-shaped) hollow fiber structures. These results indicate that novel silica structures can be created by transcription of various superstructures formed in binary gels through the hydrogen-bonding interaction, and the amino group of the p-aminophenyl aldopyranosides acts as an efficient driving force to create novel silica nanotubes. Furthermore, electron energy-loss spectroscopy (ELLS) provided strong evidence for the inner hollow structure of the double-helical silica nanotube. This is a novel and successful example that a variety of new silica structures can be created using a library of carbohydrate gel fibers as their templates.

• STI Policy Review
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• v.3 no.2
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• pp.152-171
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• 2012

In April 2001, many Japanese national institutes were reorganized as Independent Administrative Institutions (IAI) based on the General Act for Independent Administrative Institutions and the act for each institution. Under the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the National Institute for Materials Science (NIMS) was established by the merger of the National Research Institute for Metals (NRIM) and the National Institute for Research in Inorganic Materials (NIRIM). One of the biggest changes was the expansion of autonomous administration. The nanotechnology and material R&D field was prioritized in the 2nd (2001-2005) and the 3rd (2006-2010) Science and Technology Basic Plans; subsequently, NIMS was assigned to take the initiative in nanotechnology as well as materials science. NIMS has proactively expanded research fields through the introduction of researchers from polymers, electronics, and biotechnology as well as member institutes of the World Materials Research Institute Forum (WMRIF). Globalization has been promoted through programs that include the International Center for Young Scientists (ICYS) and the International Center for Materials Nanoarchitectonics (MANA). The 4th Science and Technology Basic Plan (2011-2015) emphasizes outcomes-recovery and rebirth from the disaster, green innovation, and life innovation. The Midterm Plan for NIMS also follows it. R&D collaboration by multi-partners (that include industry, university, and GRI) should be strategically promoted where GRI are especially required to play a hub function for innovative R&D and open innovation. NIMS highlights are Tsukuba Innovation Arena (TIA) and the Nanotechnology Platform Project. On January 20, 2012, a new organization was decided on by the Japanese Government where several IAI from different science and technology areas will be merged to realize more effective R&D as well as administrative cost reductions. NIMS is also supposed to be merged with 4 other R&D IAI under MEXT by the end of 2013.