• Macromolecular Research
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• v.12 no.6
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• pp.581-585
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• 2004

A copolymer P[OSA-MI] was synthesized by copolymerization of its corresponding monomers, N-phenyl maleimide (MI) and 2-octen-l-ylsuccinic anhydride (OSA). The polymer (poly[2-[1-(2,5-dioxo-l-phenylpyrroli­din-3-ylmethyl)heptyl]-succinic acid 4-(2-$\{$ethyl-[4-(4-nitrophen-ylazo)phenyl]amino$\}$ethyl)ester]) P[DR1MA-MI] was obtained from the reaction of P[OSA-MI] with 2-[4-(4-nitrophenylazo)-N-ethylphenylamino] ethanol (DR1). A stable monolayer of P[DRIMA-MI] was formed by spreading the solution of the polymer in chloroform. In Y-type Langmuir-Blodgett (LB) films prepared using this Langmuir-Blodgett method, the second harmonic waves generated from adjacent mono layers canceled each other out. In X-and Z-type LB films, the second harmonic intensity increased upon increasing the number of monolayers, but this increase was somewhat smaller than predicted by the square law. This phenomenon is due to defects or imperfect alignment of the dipoles in the LB film. The generation of second harmonic waves from Y-type LB films having an even number of mono layers supports this argument. The degree of imperfection seemed to increase as the number of layers increased. The second-order nonlinear optical properties of spin-cast films of these polymers were also measured. The largest second harmonic coefficient of the poled P[DRIMA-MI] film coated on a glass plate was 19 pm/V.

• Journal of Food Hygiene and Safety
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• v.24 no.4
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• pp.385-390
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• 2009

This survey was conducted to monitor the total sugar, sodium, and artificial sweetener contents of light meals from the school zone in Gwangju, from November, 2008 to April, 2009. A total of 100 samples were tested. HPLC/ELSD was used for the determination of total sugar contents and AAS for sodium contents. Total sugar amounts were the sum of both mono-and disaccharide according to nutritional information standard defined by the Korea Food and Drug Administration. The results were as follows by the form of total sugar content(sodium content): $5.7\;{\pm}\;1.9%$($4.6\;{\pm}\;1.6\;mg/g$) for Tteokbokki, $7.6\;{\pm}\;5.1%$($5.4\;{\pm}\;2.7\;mg/g$) for Chicken(skewed), $15.4\;{\pm}\;3.2%$($3.0\;{\pm}\;0.9\;mg/g$) for Bun(fish-shaped), $0.6\;{\pm}\;0.3%$($3.7\;{\pm}\;1.0\;mg/g$) for Sundae, $0.9\;{\pm}\;0.3%$($7.4\;{\pm}\;1.4\;mg/g$) for Oden(with broth), $20.5\;{\pm}\;6.2%$($2.9\;{\pm}\;0.6\;mg/g$) for Waffle, $6.8\;{\pm}\;2.2%$($4.7\;{\pm}\;1.0\;mg/g$) for Hotdog, $14.2\;{\pm}\;2.8%$($3.1\;{\pm}\;1.6\;mg/g$) for Hotteok, $6.6\;{\pm}\;2.1%$($3.9\;{\pm}\;0.6\;mg/g$) for Toast, $10.1\;{\pm}\;3.7%$($2.3\;{\pm}\;0.7\;mg/g$) for Fry(sweet potato), $1.6\;{\pm}\;0.7%$($4.0\;{\pm}\;0.7\;mg/g$) for Fry(etc), and $9.3\;{\pm}\;2.4%$($4.0\;{\pm}\;0.6\;mg/g$) for Doughnut. In addition, sodium saccharin, one of the artificial sweeteners, was tested. Among 60 samples from February to April, 2009, 11 samples had sodium saccharin(6.7~101.0 mg/kg).

• Korean Journal of Clinical Pharmacy
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• v.20 no.1
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• pp.50-55
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• 2010

Cefetamet pivoxil is a prodrug of cefetamet possessing a broad spectrum of activity against many aerobic gram-positive and -negative organisms. Although many literatures in abroad had introduced its pharmacokinetics about two decays ago, no data have been revealed in Korean subjects. Therefore, this study was aimed to investigate the pharmacokinetics of cefetamet following a single oral administration of cefetamet pivoxil in Korean healthy volunteers. After an overnight fast, a tablet of cefetamet pivoxil (500 mg) was given to eight volunteers, and blood samples were serially taken up to 12 h. Plasma concentrations of cefetamet were determined by HPLC with UV detection. Cefetamet reached the peak concentration ($2.0{\pm}1.3\;{\mu}g/ml$) at $3.0{\pm}0.8$ h, and mono-exponentially decayed at a half-life of $2.6{\pm}0.9$ h. Three volunteers represented very low systemic exposure compared to the others, which provided very large inter-individual variation in Cmax, and AUC. The present results were discussed and reviewed with the previously published data, and a couple of points are suggested for clinical trials of this drug in Korean subject including bioequivalence study.

• Economic and Environmental Geology
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• v.19 no.1
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• pp.25-33
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• 1986

The geology of the Jeju island is characterized by the occurrence of thick voluminous basaltic lava flows and minor trachytic lavas. The land form can be divided topographically into the lava plateau, the shield-shaped Halla volcanic edifice and the parasitic cones whose number is more than 360, which is closely related to the cyclic volcanism of the island. Especially, the trachytic lavas seem to be the latest differentiation products of the cyclic activities and largely classified into two groups (Backlokdam group and Sanbangsan group) on the basis of the occurrence and the petrography. The paleomagnetism and the radiometric age on the two groups of trachyte suggest a lower and an upper time limits of the volcanic stratigraphy of the island. An average age of the trachyte of the Sanbangsan group is $0.733{\pm}0.056m.y.$, and is correlated to a horizon a little lower than the boundary (0.69m.y.) between the Brunches normal epoch and Matuyama reversed epoch. An average age of $0.025{\pm}0.008m.y.$ determined from the Backlokdam trachyte may be corrected to anyone horizon of the Laschamp, or the Lake Biwa, or the Lake Mono excursion. The two groups of trachytes are distributed with the latitude difference of 9'($0.15^{\circ}$), and with age difference of about 0.71 m.y. Assuming that the two trachyte groups were erupted from the same stationary hot spot, the lithosphere comprising the Jeju island is considered to have moved southward with a rate of about 2.3 cm/year.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.629-636
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• 2008

This study was carried out to compare the quality of beef from outdoor-reared before finishing and indoor-reared Hanwoo. Among the experimental animals, $28{\pm}4$ mon-aged Hanwoo cows (n=5) were outdoor-reared for 7 mon (April-November) and then indoor-reared for 6 mono The 6 mon-aged Hanwoo steers (n=10) were indoor-reared for 24 mono The M. longissimus from all animals were stored at $4{\pm}0.2^{\circ}C$ for 7 days. Carcasses from outdoor-reared cattle before finishing were lighter, firmer, maturer, and leaner than indoor-reared (p<0.05). The beef from outdoor-reared cattle had lower crude fat and n-6 PUFA contents, n-6/n-3 ratio, and higher n-3 PUFA and SFA contents than indoor-reared (p<0.05). The pH and water-holding capacity were lower in beef from outdoor-reared cattle than in indoor-reared (p<0.05). The aroma pattern by electronic nose was discriminately different between beef from outdoor-reared and indoor-reared cattle. During storage, beef from outdoor-reared cattle showed lower lipid and myoglobin oxidation stabilities, and a darker and less red color than indoor-reared.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.303-310
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• 2005

Vegetation composition and structure of forest community around Mt. Kumbong, Uiseong-Gun, Korea, were studied using a qualitative and a quantitative approach. Vegetation types and various ecological characteristics including constancy classes, relative coverage, species diversity and interspecific similarity of the major component species were analyzed. Seventy relatives were sampled in $100 m^2$ plots. Forest communities were grouped into mountain vegetation and lower-valley vegetation. The former were divided into 3 communities (Quercus mongolica, Quercus variabilis and Quercus dentata communities). The latter was an Acer mono community. Vegetation units were classified into ten groups. Woody vegetation coverage was $50\~65\%$. The lower-valley vegetation type showed from $2.06\pm0.25\;to\;2.31\pm0.26$ in the species diversity. The species showing interspecific similarity over 0.5 with Quercus mongolica appeared to be Pinus densiflora, Quercus dentata and Tilia amurensis in the tree and subtree layer, and Lindera obtusiloba, Fraxinus sieboldiana, Carex humilis and Carex siderostica in the shrub and herb layer, The species showing higher interspecific similarity with Acer mono were Cornus controversa and Ulmus davidiana in the tree and subtree layer, and Philadelphus schrenchkii and Aristolochia manshuriensis in the shrub and herb layer.

• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.55-72
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• 1995

The purpose of this study is to evaluate the effects of mechanical and thermal fatigue on the shear bond strength(SBS) in orthodontic brackets bonded to human premolars with chemically cured adhesive(Mono-$Lok^2$, Rocky Mountain Orthodontics). Two types of metal brackets (Ormesh, Microloc) and three types of ceramic brackets (Fascination, Starfire, Transcend 2000) were used in this study. The $10^6$ loadcycles of $|7.4{\times}10{^2}sin2{\pi}ft|g{\cdot}cm$ and the 1,000 thermocycles of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ baths were acturated as mechanical and thermal fatigue stress, and SBS were measured after each fatigue test. The fracture sites were examined by stereoscope and scanning electron microscope. The results obtained were summarized as follows, 1. In static shear bond test, Fascination brackets showed the maximum SBS($20.78\pm3.45$ MPa) and Microloc brackets showed the minimum SBS($14.88\pm3.10$ MPa). Fascination and Starfire brackets showed significantly greater SBS than Microloc brackets(P<0.05). 2. In mechanical fatigue test, Fascination brackets showed the maximum SBS ($20.19\pm3.45$ MPa) and Starfire brackets showed the minimum SBS($9.10\pm8.33$ MPa). The SBS or Transcend 2000 brackets(P<0.01) and Starfire brackets(P<0.05) significantly decreased after $10^6$ loadcycles. 3. In thermocycling test, Ormesh brackets showed the maximum SBS ($19.36\pm2.76$ MPa) and Starfire brackets showed the minimum SBS($11.94\pm6.86$ MPa). The SBS of Transcend 2000(P<0.01), Microloc and Starfire brackets(P<0.05) significantly decreased after $10^3$ thermocycles. 4. Failure sites of thermocycling groups were similar to those of static groups but after mechanical fatigue test, Ormesh and Transcend 2000 brackets failed at the bracket/resin interface and Microloc brackets failed within adhesive. Facination brackets failed at the enamel/resin interface irrespective of experimental condition.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.601-606
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• 2000

Nickel mono-silicide(NiSi) shows no increase of resistivity as the line width decreases below 0.15$\mu\textrm{m}$. Furthermore, thin silicide can be made easily and restrain the redistribution of dopants, because NiSi in created through the reaction of one nickel atom and one silicon atom. Therefore, we investigated the deposition condition of Ni films, heat treatment condition and basic properties of NiSi films which are expected to be employed for sub-0.15$\mu\textrm{m}$ class devices. The nickel silicide film was deposited on the Si wafer by using a dc-magnetron sputter, then annealed at the temperature range of $150~1000^{\circ}C$. Surface roughness of each specimen was measured by using a SPM (scanning probe microscope). Microstructure and qualitative composition analysis were executed by a TEM-EDS(transmission electron microscope-energy dispersive x-ray spectroscope). Electrical properties of the materials at each annealing temperature were measured by a four-point probe. As the results of our study, we may conclude that; 1. SPM can be employed as a non-destructive process to monitor NiSi/NiSi$_2$ transformation. 2. For annealing temperature over $800^{\circ}C$, oxygen pressure $Po_2$ should be kept below $1.5{\times}10^{-11}torr$ to avoid oxidation of residual Ni. 3. NiSi to $NiSi_2$ transformation temperature in our study was $700^{\circ}C$ from the four-point probe measurement.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.4
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• pp.207-217
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• 2011

In this study the complex formation reactions between uranium(VI) and 2,6-dihydroxybenzoate (DHB) as a model ligand of humic acid were investigated by using UV-Vis spectrophotometry and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The analysis of the spectrophotometric data, i.e., absorbance changes at the characteristic charge-transfer bands of the U(VI)-DHB complex, indicates that both 1:1 and 1:2 (U(VI):DHB) complexes occur as a result of dual equilibria and their distribution varies in a pH-dependent manner. The stepwise stability constants determined (log $K_1$ and log $K_2$) are $12.4{\pm}0.1$ and $11.4{\pm}0.1$. Further, the TRLFS study shows that DHB plays a role as a fluorescence quencher of U(VI) species. The presence of both a dynamic and static quenching process was identified for all U(VI) species examined, i.e., ${UO_2}^{2+}$, $(UO_2)_2{(OH)_2}^{2+}$, and $(UO_2)_3{(OH)_5}^+$. The fluorescence intensity and lifetimes of each species were measured from the time-resolved spectra at various ligand concentrations, and then analyzed based on Stern-Volmer equations. The static quenching constants (log $K_s$) obtained are $4.2{\pm}0.1$, $4.3{\pm}0.1$, and $4.34{\pm}0.08$ for ${UO_2}^{2+}$, $(UO_2)_2{(OH)_2}^{2+}$, and $(UO_2)_3{(OH)_5}^+$, respectively. The results of Stern-Volmer analysis suggest that both mono- and bi-dentate U(VI)-DHB complexes serve as groundstate complexes inducing static quenching.

• Journal of the Korean Applied Science and Technology
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• v.20 no.1
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• pp.44-50
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• 2003

We studied on the preparation and evaluation of O/W type microemulsion containing "wax, liquid paraffine and quaternary ammonium salt". And also it was obtained to stability of microemulsions by mono ethylene glycol(MEG) addition. The microemulsions were generally prepared at 96${\sim}$97$^{\circ}C$ by the phase inversion method. We used polyoxyethylene(20) sorbitan monooleate(POE(20)SMO) and distearyl dimethyl ammonium chloride(D.D.A.C.) as the emulsifiers at microemulsion preparation. From the results, we could get best condition for microemulsion preparation, in case of oil phase, montanic ester wax ; 1.1wt%, paraffine wax ; 1.1wt%, liquid paraffine ; 3.1wt%, propylene glycol ; 0.6wt% and ethylene glycol monobutyl ether ; 0.6wt%, when the ratio(wt%) of D.D.A.C. and POE(20)SMO were 2 : 3. And also we could obtained that the distributed particle size of the final microemulsions were about 8${\pm}$1.5nm and the mean particle size was 7${\pm}$0.5nm. We got following results from final microemulsions that the percent of transmittance; 96${\sim}$98% at 700nm. And the microemulsion blended with MEG of 5${\sim}$15wt% showed smaller particle size and more stable distribution than non-containing MEG.