• 한국광학회지
• /
• 제14권6호
• /
• pp.573-577
• /
• 2003

Hong-Ou-Handel 간섭계를 이용한 광자쌍의 4차 간섭실험에서 두 광자의 뭉침이 단일계수에 미치는 영향을 조사하였다. 검출기의 단일광자 시간 분해능보다 짧은 시간간격으로 두 광자가 검출기에 입사할 때 하나의 검출기에서 측정되는 단일계수가 현저하게 줄어드는 변화를 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.1469-1471
• /
• 2009

Effect of contamination of liquid crystal on the electrical behavior of liquid crystal display (LCD) by spilled components from color filter layer was investigated. It is noted that the level of contamination was different following the kind of liquid crystal and organic layers. Transmittance curve of LCD cell was shifted by spilled components of color filter and BM materials. C-V curve also showed different behavior following color filter type. The results obtained show the image sticking of LCD can be varied by pairing liquid crystal with color filter materials.

• Bulletin of the Korean Chemical Society
• /
• 제15권8호
• /
• pp.654-658
• /
• 1994

Rate constants have been measured spectrophotometrically for the nucleophilic substitution reactions of p-and m-nitrophenyl 2-furoates (4 and 5, respectively) with alkali metal ethoxides ($EtO^-M^+$) in absolute ethanol at 25$^{\circ}$C. The reactivity of $EtO^-M^+$ toward 4 is in the order $EtO^-K^+$ > $EtO^-Na^+$> $EtO^-Li^+$ > $EtO^-K^+$+ 18-crown-6 ether. This is further confirmed by an ion pairing treatment method. The present result indicates that (1) ion paired $EtO^-M^+$ is more reactive than dissociated $EtO^-$ ; (2) the alkali metal ions ($K^+,\;Na^+,\;Li^+$) behave as a catalyst; (3) the catalytic effect increases with increasing the size of the metal ion. A similar result has been obtained for the reaction of 5, however, the catalytic effects shown by the metal ions are more significant in the reaction of 5 than in that of 4.

• Bulletin of the Korean Chemical Society
• /
• 제13권3호
• /
• pp.240-245
• /
• 1992

The effect of the addition of sodium dodecyl sulfate (SDS) to a buffered mobile phase (pH 3.4) on the retention of nucleotides, nucleosides and bases was investigated with a polyvinyl alcohol (PVA) column. Depending on the concentration of SDS, two different trends in the retention of nucleosides and bases containing an $NH_2$ group were observed. If the concentration of SDS was less than 5.5 mM, the retention of compounds containing an $NH_2$ group increased as the concentration of SDS in the mobile phase increased. In contrast, if the concentration was greater than 5.5 mM, the retention of compounds containing an $NH_2$ group decreased. Thus, the SDS acted as an ion-pairing reagent at lower concentration but formed micelles at higher concentrations. The retention behavior of the nucleosides and bases in the presence of a micellar concentration of SDS in the mobile phase on the PVA column was compared to the retention behavior on other types of columns.

• 한국광학회지
• /
• 제14권2호
• /
• pp.130-134
• /
• 2003

매개하향변환과정에서 발생한 광자쌍과 Hong-Ou-Handel 간섭계를 이용한 4차 간섭실험에서 두 광자가 빔분할기에 동시에 입사할 때 빔분할기의 한 쪽 출구로만 두 광자가 쌍을 이루어 빠져나가는 두-광자의 공간적인 뭉침 효과를 관측하였다. 또한 검출기의 단일광자 시간 분해능보다 짧은 시간에 두 광자가 쌍으로 입사할 때 하나의 검출기에 의한 단일계수와 비교하였다.

• Bulletin of the Korean Chemical Society
• /
• 제22권7호
• /
• pp.669-672
• /
• 2001

Pseudo-first-order rate constants have been measured spectrophotometrically for the title reactions. The plot of kobs vs the concentration of alkali metal ethoxides is linear for the reactions performed in the presence of complexing age nt, 18-crown-6 ether, but curved upwardly for the corresponding reactions performed in the absence of the complexing agent, indicating that the alkali metal ions studied in this study behave as a catalyst. The catalytic effect was found to increase in the order Li+ << K+ ${\leq}$ Na+. Second-order rate constants were determined for the reactions with dissociated free ethoxide (kEtO-) and with ion paired alkali metal ethoxides (kEtO-M+ ) from ion pairing treatments. The magnitude of catalytic effect (kEtO-M+/kEtO-) was found to be 2.3, 9.5 and 8.7 for the reaction of 8-(5-nitroquinolyl) 2-furoate, while 1.4, 3.6 and 4.2 for that of 4-nitrophenyl 2-furoate, indicating that the catalytic effect is larger in the reaction of the former substrate than in that of the latter one. The larger catalytic effect was attributed to two possible complexing sites with alkali metal ions in the former substrate.

• Bulletin of the Korean Chemical Society
• /
• 제34권6호
• /
• pp.1745-1750
• /
• 2013

A novel green aqueous mobile phase modified with room temperature ionic liquids (RTILs) was employed in the absence of volatile organic solvents or ion-pairing reagents to analyze thiamine, a very polar compound, by reverse phase high performance liquid chromatography (RP-HPLC). Due to its strongly hydrophilic nature, thiamine was eluted near the column dead time ($t_0$) using a mobile phase without adding RTILs or ion-pairing reagents, even if a 100% aqueous mobile phase, which has weak elution power under reverse phase conditions, was used. Thus, 1-ethyl-3-methyl-imidazolium hexafluorophosphate ([EMIM][$PF_6$]), which has the strongest chaotropic effect, was selected as a mobile phase additive to improve retention and avoid baseline disturbances at $t_0$. Various mobile phase parameters such as cation moiety, chaotropic anion moiety, pH and concentration of RTILs were optimized to determine thiamine at the proper retention time. Method validation was performed to assess linearity, intra- and inter-day accuracy and precision, recovery and repeatability; all results were found to be satisfactory. The developed method was also compared to the current official United States Pharmacopoeia (USP) and Korean Pharmacopoeia (KP) methods using an organic mobile phase containing an ionpairing reagent by means of evaluating various chromatographic parameters such as the capacity factor, theoretical plate number, peak asymmetry and tailing factor. The results indicated that the proposed method exhibited better efficiency of thiamine analysis than the official methods, and it was successfully applied to quantify thiamine in pharmaceutical preparations.

• Bulletin of the Korean Chemical Society
• /
• 제22권7호
• /
• pp.673-677
• /
• 2001

Pseudo-first-order rate constants have been measured spectrophotometrically for the reactions of 8-(5-nitroquinolyl) 3-furoate with alkali metal ethoxides in anhydrous ethanol. The plot of kobs vs the concentration of alkali metal ethox ides is linear for the reactions performed in the presence of a complexing agent, 18-crown-6 ether, but exhibits upward curvatures for the corresponding reactions performed in the absence of the complexing agent, indicating that the alkali metal ions in this study behave as catalysts. Second-order rate constants were determined for the reactions with dissociated free ethoxide (kEtO-) and with ion paired alkali metal ethoxides (kEtO-M + ) from ion pairing treatments. The magnitude of catalytic effect (kEtO-M + /kEtO-) was found to be 1.7, 3.4 and 2.5 for the reaction of 8-(5-nitroquinolyl) 3-furoate, while 1.4, 3.6 and 4.2 for that of 4-nitrophenyl 2-furoate, 1.8, 3.7 and 2.4 for that of 8-(5-nitroquinolyl) benzoate, and 2.0, 9.8 and 9.3 for that of 8-(5-nitroquinolyl) 2-furoate with EtO- Li+ , EtO- Na+ and EtO- K+ , respectively. A 5-membered chelation at the leaving group is suggested to be responsible for the catalytic effect shown by alkali metal ions.

• 대한한의학방제학회지
• /
• 제16권1호
• /
• pp.65-78
• /
• 2008

Objectives : this study was to access the effect of Hyeonggaeyeongyotang water extracts, a polyherbal formula has been used as folk medicine, on the fertility and early embryonic development of male and female Wistar rats when administered by oral gavage. Methods : In male rats, Hyeonggaeyeongyotang extract were dosed 4 weeks before pairing and 2 weeks after mating including the mating periods up to termination after necropsy of the majority of the females. In female rats, they were dosed 2 weeks before pairing, and from Day 0 to Day 7 of gestation. This study was conducted in accordance with the recommendations of the KFDA Guideline [2005-60] for Detection of Toxicity to Reproduction for Medicinal Products. Results: 1. No Hyeonggaeyeongyotang extract treatment-related changes on the clinical signs and mortalities, the Food consumptions, the Body weights and gains were demonstrated in all dosed levels tested in this study except for 500ml/kg-dosing male group in which a significant(p<0.05) increase of body gains was detected during day 0-7 after dosing. 2. No Hyeonggaeyeongyotang extract treatment-related changes on the pre-coital intervals, the estrus cycles, the mating index, conception rate and fertility index were demonstrated in all dosed levels tested in this study. 3. No Hyeonggaeyeongyotang extract treatment-related gross findings on reproductive organs, the weights of reproductive organs, histopathological findings on reproductive organs, the corpora lutea number, implantation site number, live fetus number, number of resorpted embryo and pre-and post-implatation loss were demonstrated in all dosed levels tested in this study. Conclusions : Base on the results, it is considered that the NOAEL (No-Observed-Adverse-Effect Level) for fertility and early embryonic development toxicity of Hyeonggaeyeongyotang extract was under 2000ml/kg/day in Wistar male and female rats because there no treatment-related changes on the fertility and early embryonic developmental index were demonstrated in all dosed levels tested.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권15호
• /
• pp.6273-6278
• /
• 2015

Objective: This study assessed the association between subjective body image or objective body mass index (BMI) and the risk of daily smoking in Korean adolescents, with a purpose of identifying the most suitable models. Materials and Methods: Using the 2013 9th Korea Youth Risk Behavior Web-based Survey data for 72,435 students, odds ratios were calculated for daily smoking in the past month, according to the subjective body image and calculated BMI using a respective multiple logistic regression model. The combined effect of these two factors was also analyzed by pairing a BMI category with a subjective body image category, using odds ratios for the same event within each sex group. Results: Among the surveyed students, 7.2% of boys and 1.8% of girls were classified as daily smokers. Students who perceived themselves as being very obese tended to be at lower risk of daily smoking (OR=0.61 in boys with 95% CI=0.47 to 0.79; OR=0.66 in women with 95% CI=0.47 to 0.93). In addition, boys within the obese or overweight BMI category showed a lower risk of daily smoking (OR=0.86, 95% CI: 0.77-0.96). Lean BMI was significantly associated with higher odds ratios for daily smoking only in female students (OR=1.24, 95% CI: 1.02-1.52). When pairing these two objective and subjective factors, results suggested that subjective body image has a greater effect on daily smoking than BMI in both boys and girls. Conclusions: In both male and female students, subjective body image had a greater effect on daily smoking than body mass index. A model using the combination of BMI and subjective body image was the best fit in girls, in contrast to the model using subjective body image only best suitable in boys, for the prediction of daily smoking. These results including several factors associated with daily smoking in Korean students, provide useful data for the development and implementation of smoking intervention and cessation programs for adolescents.