• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.413-417
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• 2000

In this study, a direct detection system for triazine derivative herbicides was developed using the photosynthetic reaction center (RC) from the purple bacterium, Rhodobacter sphaeroides, and surface plasmon resonance (SPR) apparatus. The histidine-tagged RCs were immobilized on an SPR gold chip using nickel-nitrilotriacetic acid groups as a binder for one of the triazine herbicide, atrazine. The SPR responses were proportional to the sample concentrations of atrazine in the range 0.1-1 $\mu\textrm{g}$/mL. The sensitivity of the direct detection of atrazine using the RC-assembled sensor chip was higher than that using the antibody-immobilized chip. The other types of herbicides, DCMU or MCPP, were not detected with such high sensitivity. The results indicated the high binding selectivity of the RC complex.

• Journal of Powder Materials
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• v.10 no.2
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• pp.129-135
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• 2003

Nanocrystalline powders of $MnFeP_{1-x}As_x$(x=0.45-0.6) have been synthesized by mechanochemical reaction at room temperature using high-energy ball milling from mixtures of Mn, Fe, P, and As Powders. It has been found that a mechanically induced self-propagating reaction (MSR) occurs within 2 hours of milling and it produces very fine polycrystalline powder having a hexagonal $Fe_2P$ structure. Further milling up to 24 hours did not change the crystalline and average particle sizes or the phase composition of the milling product. When x is 0.65, no reaction among the reactants has been observed even after 24 hours of milling. As the P content decreases in $MnFeP_{1-x}As_x$, the incubation time for the MSR has increased and the lattice constants in both a and c axes have changed.

• Journal of Powder Materials
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• v.2 no.2
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• pp.149-157
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• 1995

In this study, an attempt was made to fabricate TiAl as well as its in situ composite via combustion synthesis. The processing variable of the combustion synthesis which include aluminum content and the heating rate were found to affect the combustion temperature. The combustion temperature measured, however, was lower than the melting temperature of TiAl and the reaction product were found to include incomplet reaction products. Carbon was added in order to increase the combustion temperature as well as to form in situ reinforcements. The reaction products showed homogeneous microstructures with carbide phases formed within indicating that the addition of carbon increased the combustion temperature above the melting temperature of TiAl.

• Nuclear Engineering and Technology
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• v.31 no.6
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• pp.66-82
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• 1999

The national long-term R&D program, updated in 1997, requires Korea Atomic Energy Research Institute(KAERI) to complete by the year 2006 the basic design of Korea Advanced Liquid Metal Reactor(KALIMER), along with supporting R&D work, with the capability of resolving the issue of spent fuel storage as well as with significantly enhanced safety. KALIMER is a 150 MWe pool-type sodium cooled prototype reactor that uses metallic fuel. The conceptual design is currently under way to establish a self-consistent design meeting a set of major safety design requirements for accident prevention. Some of the current emphasis includes those for inherent and passive means of negative reactivity insertion and decay heat removal, high shutdown reliability, prevention of and protection from sodium chemical reaction, and high seismic margin, among others. All of these requirements affect the reactor design significantly and involve extensive supporting R&D programs. This paper summarizes some of the results of conceptual engineering and design analyses performed for the safety of HAMMER in the area of inherent safety, passive decay heat removal, sodium water reaction, and seismic isolation.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1590-1600
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• 2014

Cinchona-based bifunctional catalysts have been extensively employed in the field of organocatalysis due to the incorporation of both hydrogen-bonding acceptors (quinuclidine) and hydrogen-bonding donors (e.g., alcohol, amide, (thio)urea and squaramide) in the molecule, which can simultaneously activate nucleophiles and electrophiles, respectively. Among them, cinchona-derived (thio)urea and squaramide catalysts have shown remarkable application potential by using their bifurcated hydrogen bonding donors in activating electrophilic carbonyls and imines. However, due to their bifunctional nature, they tend to aggregate via inter- and intramolecular acid-base interactions under certain conditions, which can lead to a decrease in the enantioselectivity of the reaction. To overcome this self-aggregation problem of bifunctional organocatalysts, we have successfully developed a series of sulfonamide-based organocatalysts, which do not aggregate under conventional reaction conditions. Herein, we summarize the recent applications of our cinchona-derived sulfonamide organocatalysts in highly enantioselective methanolytic desymmetrization and decarboxylative aldol reactions. Immobilization of sulfonamide-based catalysts onto solid supports allowed for unprecedented practical applications in the synthesis of valuable bioactive synthons with excellent enantioselectivities.

• Journal of the Korean Society of Radiology
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• v.2 no.1
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• pp.31-34
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• 2008

The neutron capture spectrum for the light nuclide was very useful to study the nuclear structure. In the present study, the capture gamma-ray from the 27-keV resonance of $^{19}F(n,g)^{20}F$ reaction were measured with an anti-Compton NaI(Tl) spectrometer and the 3-MV Pelletron accelerator of the Research Laboratory for Nuclear Reactors at the Tokyo institute of technology. A neutron Time-of-Flight method was adopted with a 1.5 ns pulsed neutron source by the $^7Li(p,n)^7Be$ reaction. In the present experiment, a Teflon(($CF_2$)n) sample was used The sample was disk with a diameter of 90mm. The thickness of sample was determined so that reasonable counting rates could be obtained and the correction was not so large for the self-shielding and multiple scattering of neutrons in the sample, and was 5mm. The primary gamma-ray transitions were compared with previous measurement of Kenny.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.264.2-264.2
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• 2013

Molecular layer deposition (MLD) is sequential, self-limiting surface reaction to form conformal and ultrathin polymer film. This technique generally uses bifunctional precursors for stepwise sequential surface reaction and entirely organic polymer films. Also, in comparison with solution-based technique, because MLD is vapor-phase deposition based on ALD, it allows epitaxial growth of molecular layer on substrate and is especially good for surface reaction or coating of nanostructure such as nanopore, nanochannel, nanwire array and so on. In this study, polyurea film that consisted of phenylenediisocyanate and phenylenediamine was formed by MLD technique. In situ Fourier Transform Infrared (FTIR) measurement on high surface area SiO2 substrate was used to monitor the growth of polyurethane and polyurea film. Also, to investigate orientation of chemical bonding formed polymer film, plan-polarized grazing angle FTIR spectroscopy was used and it showed epitaxial growth and uniform orientation of chemical bones of polyurea films.

• Journal of Families and Better Life
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• v.29 no.2
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• pp.73-87
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• 2011

The purpose of this study is to investigate the influence of children's socia-demographic variables(i.e., gender, birth order, and the amount of time staying in kindergarten) on, leadership, self-regulation and children's peer play behaviors. The participants of this study are 336 children aged between five and seven in four classes in a private kindergarten and eight classes in a private preschool located in the capital region. The results revealed that, girls showed more leadership, self-regulation, and play interaction section than boys: whereas, boys showed higher response in play disruption and the lack of play disconnection. However, birth order, did not have a significant effect on the sub-domain of leadership, self-regulation competence, and peer play behaviors. As for the duration children stay in preschool or in preschool or kindergarten, children who spend half-day showed higher reaction in behavioral self-control and emotional taking abilities than children who stay in the preschool or kindergarten full day. On the other hand, self-esteem of full-time children was higher than half-time children. Children who were emotionally sensitive, knew how to lead their peer group, and those who were sociable and self-regulated presented to be more active in peer-interaction than others. Second, as the result of the correlation analysis reveals, children's leadership, self-regulation competence, peer play behaviors, and play interaction had a meaningful effect on the sub-variations of children's leadership and self-regulation and they showed significant influence upon play disruption and play disconnection. In addition, girls who were not able to manage or to inspect their behavior and had insensitive emotion demonstrated higher tendency to play disconnected. Children, who participated in full-day program with having difficulties in self-regulation or inspecting their behavior properly but had a strong leadership and insensitive showed play disruption highly.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.101-101
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.509-510
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• 2006