• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.661-667
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• 1990

Spinel powders were synthesized at the comparatively low-temperature range(800~90$0^{\circ}C$) by the emulsion-hot kerosene drying method and the effects of kerosene-evaporative conditions on powder characteristics were investigated. In emulsion drying, more unagglomerated and sinterable powders could be synthesized through rapid evaporation of emulsion at the higher kerosene temperature. The completion of formation reaction of spinel observed at the low-temperature range confirmed the high reactivity of powders. The relative theoretical density and the fracture toughness of spinel pellets sintered at 1$650^{\circ}C$ for 4hrs. were 98% and 2.1MN/m3/2, respectively.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.385-391
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• 2006

In Korea, different kinds of genetically modified (GM) crops are under development, including GM-rice expressing insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) modified to change a single amino acid. In this study, amino acid (aa) sequences of modified Cry proteins were compared to that of known allergens, and Cry proteins expressed in GM-rice were identified by using Cry protein specific polyclonal antibody. The antigen-antibody reactions were compared between GM and commercial rice to assess the allergic risk of Cry proteins. This analysis showed no known allergen to have more than 35% aa sequence homology with modified Cry proteins in Bt rice over an 80 aa window or to have more than 8 consecutive identical aa. Sera from allergic patients showed some IgE reactivity via immunoblotting and enzyme-linked immunosorbent assay (ELISA), although no differences were seen between GM and commercial rice. Based on these results we conclude that GM rice with modified Cry proteins has no differences in its protein composition or allergenicity relative to commercial rice.

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.1044-1046
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• 2000

Catalytic copolymerization of diethyl dipropargylmalonate (DEDPM) and phenylacetylene (PA) by Mo(CO)6 and (toluene) Mo(CO)3/chloranil has resulted in the expected copolymer consiting of a polyene backbone with five-and/or six-membered rings and th e PPA structure. Both complexes exhibited not only varying degree of catalytic activity depending upon the relative mole ratio of two monomers but also characterize the types of coploymers. The former yields the polyene backbone containing only five-membered rings as well as PA while the latter produces the polymers consisting of both five-and six-membered ring structure. Comparative studies show that Mo(CO)6 exhibits reactivity toward DEDPM alone, thus catalyzing initially metathesis cyclopoly-merization of DEDPM followed by copolymerization with PA while the (toluene)Mo(CO)3/chloranil system shows affinity for both PA and DEDPM.

• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.179-182
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• 1984

MINDO/3 theoretical studies were carried out on sigmatropic hydrogen rearrangements in systems with central nitrogen atom; three systems studied being (1) N-methylformaldimine, (2) nitrous acid, and (3) formaldoxime-nitrosomethane systems. It was found that in system (1), 1,3-H shift is preferred whereas in systems (2) and (3), 1,2-H shifts are favored. The relative order of reactivity for the three systems was found to be (2) < (3) < (1), which is exactly the opposite to that found for the corresponding systems with central carbon atom.

• Korean Journal of Animal Reproduction
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• v.10 no.2
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• pp.168-174
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• 1986

These experiments were carried out to clarify the optimalconditions and interspecific cross reaction of H-Y antibody activity. H-Y antiserum was prepared in inbred SD female rats and Balb/c female mice by repeated immunization of rat newborn testis homogemate, rat and mouse spleen cells obtained from males of same strain. The activity of H-Y antibody in antiserum was tested by ELISA and biological tests. The cross reactivity of H-Y antibody was confirmed by culturing mouse and rabbit embryos in medium containing H-Y antibody and complement obtained from rat and guinea pig, respectively. The optimal condition for the activity of H-Y antibody was also investigated by culturing embryos in medium with different pH and complement concentration. The results obtained in these experiments were summarized as follows: 1. The formation rates of H-Y antibody in rats immunized with newborn testis and spleen cell were 40.0 and 50.0% respectively, and that in mouse immunized with spleen cell was 48.4%. 2. The activity of H-Y antibody was not affected by pH in range of 6.5 to 8.0, and the same was true for the relative concentration of complement to the H-Y antibody. 3. Minimum time needed for the activity of H-Y antibody was confirmed to be 0.5 to 1 hour and 24 to 48 hours respectively for the zona free embryos and intact embryos. 4. When mouse and rabbit embryos were treated with H-Y antibody obtained from rat, 46.4 and 54.8% of embryos were retarded or destroyed. From these results it could be said that H-Y antibody had strong interspecific cross reactivity.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.4
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• pp.417-428
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• 1999

The measurement of VOSCs(volatile organic sulfur compounds) in the air is nowadays a very important environmental research field. It is, however, very difficult because the concentration of the VOSC in ambient air is usually very low and the high reactivity makes it difficult to keep in container without loss of recovery. In this study, sampling method with cryogenic preconcentration is evaluated for analysis of atmospheric VOSC such as $CH_3SH,\;CH_3CH_2SH,\;CH_3SCH_3,\;CS_2,\;CH_3SSCH_3,\;CH_3SCH_2SCHA_3,\;and\;C_2H_5SSC_2H_5$ analyzed by GC-MS or GC-FID. Repeatabilities of measurement accompanied with preconcentration for 3-successive runs were in the range of 0.2~1.0% as a relative standard deviation. Stabilities up to 13 days were measured in 6 L canister and 10 L tedlar bag filled with VOSCs in ppb level. Higher stability was observed in tedlar bag as compared to canister with glass coated inner walls, and thiol compounds show dramatic losses in canister within 2~3 days. It is found that recovery over 70% was obtained in a week for all tested VOSCs when the compounds from ambient air matrix were stored in tedlar bag. It is also found that the stabilities of VOSCs are depending on humidity and coexisting compounds in matrix gas due to sample adsorption onto inner surface and reactivity. The results indicate the possibility and limitations of VOSC analysis in ambient air using container sampling method with cryogenic preconcentration.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.11-19
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• 1996

The cationic polymerization of energetic substituted oxetanes which have pendant energetic group such as azido and nitrato are investigated theoretically, using semiempirical HF/3-21G, MINDO/3, MNDO and AM1 method. The stereo- and electronic structure of binary molecular complex composed of energetic substituted oxetane and boron trifluoride can be explain by molecular orbital theory. The reactivity of propagation in the copolymerization of oxetanes can be presented by the positive charge on carbon(C2) atom of oxetane and energy level of the lowest unoccupied molecular orbital(LUMO) of propagating species of oxetanes. The reactivity ratios for copolymerization of oxetanes are a random copolymer-zation which is agree with MO calculated and experimental results. The relative equlibrium concentration of cyclic oxonium and open carbenium ions is found to be a major determinant of mechanism, owing to the rapid equilibrium of these cation forms and the expectation based on calculation that in the prepolymer propagation step, SN1 mechanism will be at least as fast as that for SN2 mechanism.

• 보존과학연구
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• s.33
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• pp.85-97
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• 2012

In this study, reliability assessment was carried out on UV(ultraviolet) indicators for the application of the indicator method on cultural heritages. As a result, some UV indicators(L, K, and M) proved to be unsuitable due to their low reactivity to UV and high reactivity to RH(relative humidity). On the other hand, indicator S showed considerable color changes and fading due to UV-B and UV-C according to the integral amount of UV irradiation. Indicator S showed the most distinct reaction to UV and a remarkable applicability to exhibition light, which are used in museums. Therefore, UV indicator S is an easy and useful monitoring tool for light environment management in cultural- property conservation facilities.

• Environmental Engineering Research
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• v.18 no.1
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• pp.29-35
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• 2013

This study noted that the actual mechanism of N-nitrosodimethylamine (NDMA) photodecomposition in the presence of $H_2O_2$ is missing from the previous works. This study investigated a key unknown reactive species (URS) enhanced by the addition of $H_2O_2$ during the photolysis of NDMA with $H_2O_2$, not hydroxyl radicals. In order to provide experimental evidences in support of URS formation, we have mainly used p-nitrosodimethylaniline, methanol, and benzoic acid as well-known probes of ${\cdot}OH$ in this study. Both loss of PNDA and formation of hydroxybenzoic acids were dependent on NDMA concentrations during the photolysis in a constant concentration of $H_2O_2$. In particular, competition kinetics showed that the relative reactivity of an URS was at least identical with ${\cdot}OH$-like reactivity. In addition, the decay of NDMA was estimated to be about 65% by the direct UV light and about 35% by the reactive species or URS generated through the photolysis of NDMA and $H_2O_2$. Therefore, our data suggest that a highly oxidizing URS is formed in the photolysis of NDMA with $H_2O_2$, which could be peroxynitrite ($ONOO^-$) as a potent oxidant by itself as well as a source of ${\cdot}OH$.

• The Journal of the Acoustical Society of Korea
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• v.21 no.8
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• pp.708-718
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• 2002

In this paper, the problems in identifying the noise sources by using the sound intensity technique are dealt with for the general radiated near-field from vibro-acoustic sources. For this purpose, a three-dimensional model structure resembling the engine room of a car or heavy equipment is considered. Similar to the practical situations, the model contains many mutually coherent and incoherent noise sources distributed on the complicated surfaces. The sources are located on the narrow, connected, reflecting planes constructed with rigid boxes, of which a small clearance exists between the whole box structure and the reflecting bottom. The acoustic boundary element method is employed to calculate the acoustic intensity at the near-field surfaces and interior spaces. The effects of relative source phases, frequencies, and locations are investigated, from which the results are illustrated by the contour map, vector plot, and energy streamlines. It is clearly observed that the application of sound intensity technique to the reactive or reverberant field, e.g., scanning over the upper engine room as is usually practiced, can yield the detection of fake sources. For the precise result for such a field, the field reactivity should be checked a priori and the proper effort should be directed to reduce or improve the reactivity of sound field.