• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2241-2247
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• 2007

A new series of chiral bent-shaped liquid crystals with an asymmetric central core based on 1,6- dihydroxynaphthalene and chiral terminal chain prepared from (S)-(?)-2-methyl-1-butanol, 1,6-naphthalene bis[4-(4-alkoxyphenyliminomethyl)]benzoates [N(1,6)-n-O-PIMB(n-2)*-(n-4)O (n = 8-11)] were synthesized. Their mesomorphic properties and phase structures were investigated by means of electro-optical, polarization reversal current, and second harmonic generation measurements in order to confirm the relationship between the molecular structure and phase structure. All odd n (n = 9 and 11) compounds, N(1,6)-9-O-PIMB7*-5O and N(1,6)-11-O-PIMB9*-7O exhibit antiferroelectric phase, whereas even n (n = 8 and 10) compounds was flexible, N(1,6)-10-O-PIMB8*-6O exhibits the ferroelectric phase but N(1,6)-8-O-PIMB6*-4O exhibits the antiferroelectric phase. These results come from the decrease of the closed packing efficiency within a layer and the lack of uniform interlayer interaction between adjacent layers, which were caused by the asymmetrical naphthalene central core. Thus, we concluded that the structure of central core as well as the terminal chain plays an important role for the emergence of particular polar ordering in phase structures.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.79-89
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• 2009

Naphthalene is a volatile, hydrophobic, and possibly carcinogenic compound that is known to have a severe detrimental effect to aquatic ecosystem. Our research examined the effects of various operating conditions (temperature, pH, initial concentration, and frequency and type of ultrasound) on the sonochemical degradation of naphthalene and OH radical production. The MDL (Method detection limit) determined by LC/FLD (1200 series, Agilient) using C-18 reversed column is measured up to 0.01 ppm. Naphthalene vapor produced from ultrasound irradiation was detected under 0.05 ppm. Comparison of naphthalene sonodegradion efficiency tested under open and closed reactor cover fell within less than 1% of difference. Increasing the reaction temperature from $15^{\circ}C$ to $40^{\circ}C$ resulted in reduction of naphthalene degradation efficiency ($15^{\circ}C$: 95% ${\rightarrow}$ $40^{\circ}C$: 85%), and altering pH from 12 to 3 increased the effect (pH 12: 84% ${\rightarrow}$pH 3: 95.6%). Pseudo first-order constants ($k_1$) of sonodegradation of naphthalene decreased as initial concentration of naphthalene increased (2.5 ppm: $27.3{\times}10^{-3}\;min^{-3}\;{\rightarrow}$ 10 ppm : $19.3{\times}10^{-3}\;min^{-3}$). Degradation efficiency of 2.5 ppm of naphthalene subjected to 28 kHz of ultrasonic irradiation was found to be 1.46 times as much as when exposed under 132 kHz (132 kHz: 56%, 28 kHz: 82.7%). Additionally, its $k_1$ constant was increased by 2.3 times (132 kHz: $2.4{\times}10^{-3}\;min^{-1}$, 28 kHz: $5.0{\times}10^{-3}\;min^{-1}$). $H_2O_2$ concentration measured 10 minutes after the exposure to 132 kHz of ultrasound, when compared with the measurement under frequency of 28 kHz, was 7.2 times as much. The concentration measured after 90 minutes, however, showed the difference of only 10%. (concentration of $H_2O_2$ under 28 kHz being 1.1 times greater than that under 132 kHz.) The $H_2O_2$ concentration resulting from 2.5 ppm naphthalene after 90 minutes of sonication at 24 kHz and 132 kHz were lower by 0.05 and 0.1 ppm, respectively, than the concentration measured from the irradiated M.Q. water (no naphthalene added.) Degradation efficiency of horn type (24 kHz) and bath type (28 kHz) ultrasound was found to be 87% and 82.7%, respectively, and $k_1$ was calculated into $22.8{\times}10^{-3}\;min^{-1}$ and $18.7{\times}10^{-3}\;min^{-1}$ respectively. Using the multi- frequency and mixed type of ultrasound system (28 kHz bath type + 24 kHz horn type) simultaneously resulted in combined efficiency of 88.1%, while $H_2O_2$ concentration increased 3.5 times (28 kHz + 24 kHz: 2.37 ppm, 24 kHz: 0.7 ppm.) Therefore, the multi-frequency and mixed type of ultrasound system procedure might be most effectively used for removing the substances that are easily oxidized by the OH radical.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.749-752
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• 2006

The house dust mites are well known to the most important causative allergens of major allergic diseases like pediatric asthma, allergic rhinitis or atopic dermatitis. This study was done for assessment of naphthalene effect against breeding suppression of the house dust mites. Twenty live adult house dust mites(Dermatophaogoides pteronyssinus) were each inoculated on mixed culture media containing 0 mg (control), 1mg, 2 mg, 3 mg, 5 mg, and 10 mg naphthalene and incubated at $25^{\circ}C$ with a relative humidity of 75%. After 4 weeks mean number of live house dust mites were 191.5, 24.3, 1.3, 1.3, 0, and 0, respectively. Above results showing that the naphthalene can suppress of breeding the house dust mites in vitro.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.543-548
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• 1990

Volatile components of fresh apricot (Prunus armeniaca var. ansu Max.) were isolated by simultaneous distillation-extraction at two different pH values of 3.1 and 7.0 and by headspace trapping method. The volatiles were analyzed by GC and GC-MS. A total of 80 components were identified in the three aroma concentrates, including 9 naphthalene derivatives that were not previously reported in apricot. Of components identified in native pH (3.1) sample, the major components were aliphatic $C_6$ aldehydes and alcohols, monoterpene alcohols, benzyl alcohol, ${\beta}-phenylethyl$ alcohol and naphthalene derivatives, while those in neutral pH(7.0) sample and headspace volatiles were aliphatic $C_6$ aldehydes and alcohols. Simultaneous distillation-extraction at pH 3.1 was significantly increased the concentration of n-hexanal, trans-2-hexenal, cis-3-hexen-1-ol, linalool oxide, linalool, ${\alpha}-terpineol$, nerol, geraniol, benzyl alcohol, ${\beta}-phenylethyl$ alcohol and naphthalene derivatives. These results demonstrate that above the components are present in glycosidically bound forms in apricot.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.483-485
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• 1991

A furanquinone substance(methyl 5-hydroxy-dinaphtho [1,2-2',3'] furan-7,12-dione-6-carboxylate) which has been isolated from the methanol extract of Paulownia tomentosa stem was synthesized by condensing 2,3-dichloro-1,4-naphthoquinone with methyl 1,4-dihydroxy-naphthalene-2-carboxylate in pyridine and identified by NMR, MS, UV, IR etc.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2285-2289
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• 2014

The solvolysis rate constants of 5-dimethylamino-naphthalene-1-sulfonyl chloride ($(CH_3)_2NC_{10}H_6SO_2Cl$, 1) in 31 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and $Y_{Cl}$ solvent ionizing scale with sensitivity values of $0.96{\pm}0.09$ and $0.53{\pm}0.03$ for l and m, respectively; the correlation coefficient value was 0.955. These l and m values can be considered to support an $S_N2$ reaction pathway having a transition state (TS) structure similar to that of the benzenesulfonyl chloride reaction. This interpretation is further supported by the activation parameters, i.e., relatively small positive ${\Delta}H^{\neq}$ (12.0 to $15.9kcal{\cdot}mol^{-1}$) and large negative ${\Delta}S^{\neq}$ (-23.1 to $-36.3cal{\cdot}mol^{-1}{\cdot}K^{-1}$) values, and the solvent kinetic isotope effects (SKIEs, 1.34 to 1.88). Also, the selectivity values (S = 1.2 to 2.9) obtained in binary solvents are consistent with the proposed mechanism.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.651-657
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• 2009

Shifts in the activity and diversity of microbes involved in aliphatic and aromatic hydrocarbon degradation in contaminated soil were investigated. Subsurface soil was collected from a gas station that had been abandoned since 1995 owing to ground subsidence. The total petroleum hydrocarbon content of the sample was approximately 2,100 mg/kg, and that of the soil below a gas pump was over 23,000 mg/kg. Enrichment cultures were grown in mineral medium that contained hexadecane (H) or naphthalene (N) at a concentration of 200 mg/l. In the Henrichment culture, a real-time PCR assay revealed that the 16S rRNA gene copy number increased from $1.2{\times}10^5$to $8.6{\times}10^6$with no lag phase, representing an approximately 70-fold increase. In the N-enrichment culture, the 16S rRNA copy number increased about 13-fold after 48 h, from $6.3{\times}10^4$to $8.3{\times}10^5$. Microbial communities in the enrichment cultures were studied by denaturing gradient gel electrophoresis and by analysis of 16S rRNA gene libraries. Before the addition of hydrocarbons, the gas station soil contained primarily Alpha- and Gammaproteobacteria. During growth in the H-enrichment culture, the contribution of Bacteriodetes to the microbial community increased significantly. On the other hand, during N-enrichment, the Betaproteobacteria population increased conspicuously. These results suggest that specific phylotypes of bacteria were associated with the degradation of each hydrocarbon.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.36-37
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• 2004

$\alpha$-Chloromethylnaphthalene is a valuable compound for obtaining of the plant growing stimulator - $\alpha$-napthylacetic acid. Chloromethylation of naphthalene by paraformaldehyde in the presence of glacial acetic acid, phosphoric and hydrochloric acids at temperature 80-85$^{\circ}C$ and duration - 6 hours the $\alpha$-chloromethyl-naphthalene yield was 55-57%. Using Box-Wilson method for mathematical planning of experiment carried out optimization of its synthesis for purpose increasing $\alpha$-chloromethylnaphthalene yield. Preliminary, one - factor experiments were carried out for selecting independence main parameters influencing on the synthesis. A full factor experiment of 2$^3$with extended matrix of planning was used for optimization. Aiming to increase the $\alpha$-chloromethylnaphthalene yield, the obtained mathematical model was used for program of sharp raising on the reply surface. The received optimal conditions for the $\alpha$-chloromethylnaphthalene synthesis were selected as following: molar ratio of naphthalene - parapfsormaldehyde of 1 : 2; temperature -105$^{\circ}C$; duration of the reaction -3 hours. The yield of $\alpha$-chloromethylnaphthalene under these optimal conditions was 75 %.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.70-77
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• 2007

Pseudomonas sp. KM1 was separated from soil contaminated by petroleum and identified. The isolated strain is Gram-positive, rod-shaped and immotile. In batch culture, the optimum cultivation temperature and pH was $35^{\circ}C$ and 7, respectively. Biodegradation of PAHs experiment with soil slurry system was performed using Pseudomonas sp. KM1. Pseudomonas sp. KM1 could degrade 7 PAHs including naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, pyrene, and fluoranthene. These mixed PAHs was easily degraded within one day except fluoranthene, which was degraded much slowly, taking several days by this isolated bacteria. Pseudomonas sp. KM1 is good candidate for bioremediation of PAHs contaminated soils. Biodegradation rates of naphthalene, phenanthrene and pyrene in soils were different at each soil, and the rates were decreased as sorption capacity increased.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.191-197
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• 2008

This work was intended for the identification of markers that are found only in the spoiled red pepper powder. When analyzed by GC/MASS, the spoiled red pepper powder contains characteristic naphthalene derivatives, 1, 2, 3, 5, 6, 7, 8, $8\alpha$-octahydro-1, $8\alpha$-dimethyl-7-(1-methylethenyl)-naphthalene and 2-isopropenyl-$4\alpha$, 8-dimethyl-1, 2, 3, 4, $4\alpha$, 5, 6, $8\alpha$-octahydronaphthalene, which have not found in the normal red pepper powder. In addition, microscopic observation and microbial enumeration of the red pepper powder had been performed. Images by scanning electron microscopy showed that the surfaces of spoiled pepper powder were rough with many kinds of microbes, compared with those of normal red pepper powder. A good correlation between the bacterial and fungal counts in the same sample was observed and could be clearly classified into two groups, the normal and the spoiled group, by difference in the microbial counts. These results suggest that the spoiled red pepper powder can be identified by a combination of GC/MASS, microbial counts, and scanning electron microscopy.