• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.82-89
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• 1989

The fluorescence of $Eu^{3+},\;Tb^{3+}$ substituted for $La^{3+}$ in Lanthanum Oxychloride (LaOCl) has been studied. The fluorescence intensity of the $Eu^{3+},\;Tb^{3+}$ in LaOCl excited by Ultra-violet light were investigated on its activator concentration and discussed as the energy transfer process. The energy transfer from $Tb^{3+}\;to\;Eu^{3+}$ take place in the $Eu^{3+}\;and\;Tb^{3+}$ codoped LaOCl crystal. This process was confirmed to the change of concentration and the measurement of fluorescence decay time.

• Journal of Plant Biotechnology
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• v.47 no.1
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• pp.73-77
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• 2020

This study was conducted to examine the vitality of Bletilla striata Rchb.f. seed treated with different concentrations sodium hypochlorite (NaOCl) for different lengths of time. This study also examined the effect of NaOCl treatment times and concentrations on swelling formation and seed germination of B. striata seed. The non-treated B. striata seed had the highest survival rate (82.7%) Treatment with more than 1.5% NaOCl negatively affected the seed survival rate, as compared to concentrations of less than 1%. The swelling formation and seed germination percentages were highest (90.1% and 94.1%, respectively) when seeds were treated with 0.5% NaOCl for 20 min. These results can be used as important basic data for the growth and restoration of B. striata and further suggest the possibility of individual restoration in habitats.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.05a
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• pp.13-13
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• 2010

복주머니난(Cypripedium)속 식물은 우리나라에 광릉요강꽃을 비롯하여 털복주머니난, 흰털복주머니란, 복주머니란, 노랑복주머니란등 5종이 분포하는 것으로 알려져 있다. 광릉요강꽃과 털복주머니란 두 종은 환경부에서 지정한 멸종위기 식물 1급과 2급에 지정되어 보호를 받고 있고 나머지 3종은 제도적으로도 보호를 받지 못하는 실정이다. 본 연구에서는 충분히 성숙한 털복주머니난과 복주머니난의 종자에 NaOCl처리를 하여 발아율을 향상시킬수 있었는데 이러한 전처리가 발아에 미치는 원인에 대한 연구를 실시하였다. 털복주머니란의 무균적인 종자발아는 1.0% NaOCl 처리구에서 70% 이상의 종자발아율을 보였으며, POM배지가 MS배지보다 신초분화가 양호했다. GA3와 활성탄(Activated charcoal)의 혼합첨가는 신초증식에 효과적이었다. 신초분화 후 저온처리는 신초의 증식 율을 증가시켰다. 한편 NaOCl 농도(0, 1, 3, 5, 10%)와 NaOCl 처리시간(0, 5, 15, 30, 45, 60분)에 따라서 복주머니란의 종자발아를 확인한 결과, NaOCl 1%를 30분간 처리하였을 때 가장 높은 발아율을 나타냈다. NaOCl을 처리하여 종자의 종피상태를 SEM과 TEM으로 관찰한 결과 NaOCl의 처리는 종피 세포벽의 부분적 해리 및 작은 구멍을 만들게 하였는데 이러한 종피의 물리화학적 변화가 물과 양분의 이동을 원활히 하여 종자의 발아를 촉진하는 것으로 사료된다. 복주머니난의 신초분화에 미치는 casein과 활성탄의 효과를 알아본 결과 casein 200 mg/L와 활성탄 200 mg/L를 혼합 첨가한 실험구에서 가장 높은 신초분화율을 보였다. 토양순화 후 생존률은 극히 저조했으며 30 개체중에 5 개체만이 다음해 어린동아를 싹틔우는 것을 확인 하였다. 본 결과들을 종합하여 보면 멸종위기식물, 특히 털복주머니란과 복주머니란의 조직배양을 통해서 서식지외 보존방안(기내증식)에 관해 가능성을 제시하였다고 생각되어 진다.

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.11.1-11.10
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• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.697-704
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• 2015

This study was carried out to investigate conveyance environment during shipping export to Japan and the optimum pre-treatment of cut Dendranthema grandiflorum 'Baekma'. Shipping from Korea to Japan, which usually takes three to five days, requires keeping the flower at the ideal temperature. When inspection took place in Japan, the ideal temperature was lost and deterioration began. Once the ideal temperature is lost, deterioration takes place. The results of this work showed that vase life was extended by treatment Chrysal RVB and NaOCl compared to the control (distilled water), and Chrysal RVB was used to maintain the flower from bud to full bloom. Bacterial growth was not observed after pretreatment with NaOCl or $ClO_2$. However, $ClO_2$ pre-treatment was observed to affect the early growth period of the bacteria. The chlorophyll content was the highest after Chrysal RVB or NaOCl pretreatment compared to the other treatments. Therefore, these results support pretreatment with NaOCl and Chrysal RVB of Dendranthema grandiflorum 'Baekma' for export to Japan.

• Journal of Environmental Science International
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• v.30 no.1
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• pp.69-76
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• 2021

The purposes of this study were to evaluate the removal characteristics of COD, Ni, and P and to derive appropriate operating conditions for the plating wastewater according to NaOCl reaction time and pH operating conditions in the BPC unit process during the plating wastewater treatment process. As a results of evaluating the removal characteristics for raw wastewater by each BPC unit process, the removal efficiencies of COD, Ni and P in BPC 1-1 unit process were 72.8%, 99.1%, and 100.0%. Therefore, the proper reaction time of NaOCl was derived as 21.1 minutes. In order to maintain the +800 mV ORP and the reaction time of 20 minutes, the temporary injection and continuous injection of NaOCl in the BPC unit process were 13.7 mL and 18.7 mL, respectively. It was found that the temporary injection method of NaOCl reduced the chemical cost by 36.5% compared to the continuous injection method. Also, Ni showed the highest removal efficiency of 97.8% at pH 10.5. On the other hand, P showed a removal efficiency of 57.4% at pH 10.0.

• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.1.1-1.11
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• 2023

Objectives: This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols. Materials and Methods: Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%. Results: The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019). Conclusions: The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

• Food Science and Preservation
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• v.15 no.2
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• pp.169-173
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• 2008

Bacillus subtilis subsp. subtilis constitutes 90% of the total viable bacteria present on Capsosiphon fulvescens. We found that hydrogen peroxide (50 ppm) and NaOCl (50 ppm) were more effective than electrolyzed water (EW, 50ppm) against B. subtilis subsp. subtilis that was isolated from this seaweed. Relative to a control, 50 ppm hydrogen peroxide reduced the total viable population by $1.8{\pm}0.4$ log CFU/g, whereas 50 ppm EW increased the total viable population by $1.7{\pm}0.5$ log CFU/g. CFUs were evaluated following 30 days of storage at $4^{\circ}C$ using air- and vacuum-packaging. Samples treated with 50 ppm hydrogen peroxide and NaOCl showed a $1.6{\pm}0.1$-fold decrease in initial hardness ($7.9{\times}10^6dyne/cm^2$), while the samples treated with 50 ppm EW had a $2.1{\pm}0.1$-fold decrease in initial hardness ($7.9{\times}10^6dyne/cm^2$). Again, measurements were performed after storage at $4^{\circ}C$ for 20 days. This study indicates that B. subtilis subsp. subtilis is the most common contaminant in aerobically or anaerobically packaged seaweed and should therefore be the main target for quality control during long-term storage. Hydrogen peroxide and NaOCl are more effective than EW in inhibiting B. subtilis subsp. subtilis and in reducing total bacterial loads in air- and vacuum-packaged seaweed.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.295-301
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• 2010

Recent studies demonstrated that the combination of chlorhexidine (CHX) and sodium hypochlorite (NaOCl) resulted in the formation of a precipitate, para-chloroaniline (PCA). Alexdidine (ALX) is a kind of biguanides like CHX, and has stronger detoxification effect against the bacterial virulence factors such as lipoteichoic acid and lipopolysacchardide compared with CHX. The purpose of this study was to determine whether PCA was formed after chemical interaction between ALX and NaOCl using mass spectrometry. Mass spectrometry was performed for the mixture of five different concentrations of ALX (1, 0.5, 0.25, 0.125, 0.0625%) and 4% NaOCl. Results showed that the peak of PCA was not detected in mixed solutions of ALX and NaOCl in mass spectrometry analysis. The color of mixed solution of ALX and NaOCl after chemical interaction was light yellow to white, but there wasn't any precipitate found.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.466-471
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• 2014

Hydrous zirconia particles were prepared from $ZrOCl_2$ aqueous solution using an electro-dialysis [ED] process. For the preparation of $(Zr,Y)(OH)_4$ precipitates, 3 mol% $YCl_3$ was added into $ZrOCl_2$ aqueous solution. During the hydrolysis of 0.5 mol/L $(Zr,Y)OCl_2$ solution at $90^{\circ}C$ a slurry solution was obtained. The ED process was used for the removal of chlorine from the slurry solution. Two kinds of slurry solution were sampled at the beginning and end of the ED process. The morphology of hydrous zirconia particles in the solution was observed using an inverted optical microscope and an FE-SEM. The hydrous zirconia particles were nano-crystalline, and easily coagulated with drying. Yttrium stabilized zirconia [YSZ] powder could be obtained by the calcination of $(Zr,Y)(OH)_4$ precipitates prepared from a $(Zr,Y)OCl_2$ solution by the ED process. The coagulated dry powders were shaped and sintered at $1500^{\circ}C$ for 2 h. The sintered body showed a dense microstructure with uniform grain morphology.