• Restorative Dentistry and Endodontics
• /
• v.35 no.2
• /
• pp.80-87
• /
• 2010

The purpose of this study was to compare the different canal irrigation methods to prevent the formation of precipitate between sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Extracted 50 human single-rooted teeth were used. The root canals were instrumented using NiTi rotary file (Profile .04/#40) with 2.5% NaOCl and 17% EDTA as irrigants. Teeth were randomly divided into four experimental groups and one control group as follows; Control group: 2.5% NaOCl only, Group 1: 2.5% NaOCl + 2% CHX, Group 2: 2.5% NaOCl + paper points + 2% CHX, Group 3: 2.5% NaOCl + preparation with one large sized-file + 2% CHX, Group 4: 2.5% NaOCl +95% alcohol+ 2% CHX. The teeth were split in bucco-lingual aspect and the specimens were observed using Field Emission Scanning Electron Microscope. The percentages of remaining debris and patent dentinal tubules were determined. Statistical analysis was performed with one-way analysis of variance (ANOVA). Energy Dispersive x-ray Spectroscopy was used for analyzing the occluded materials in dentinal tubule for elementary analysis. There were no significant differences in percentage of remaining debris and patent tubules between all experimental groups at all levels (p > .05). In elementary analysis, the most occluded materials in dentinal tubule were dentin debris. NaOCl/CHX precipitate was detected in one tooth specimen of Group 1. In conclusion, there were no significant precipitate on root canal, but suspected material was detected on Group 1. The irrigation system used in this study could be prevent the precipitate formation.

• ALGAE
• /
• v.29 no.4
• /
• pp.311-319
• /
• 2014

The biocide sodium hypochlorite (NaOCl) is widely used for controlling algal growth, and this application can be extended to marine environments as well. This study evaluates the biocidal efficiency and cellular toxicity of NaOCl on the harmful dinoflagellate Cochlodinium polykrikoides, with emphasis on pigment production and antioxidant enzyme activity. The test organism showed dose-dependent decrease in growth rate on exposure to NaOCl, and the 72 h $EC_{50}$ was measured to be $0.584mg\;L^{-1}$. NaOCl significantly decreased pigment levels and chlorophyll autofluorescence intensity, indicating possible detrimental effects on the photosystem of C. polykrikoides. Moreover, it significantly increased the activities of antioxidant enzymes, suggesting the production of reactive oxygen species in the cells. These data indicate that NaOCl exerted deleterious effects on the photosynthetic machinery and induced oxidative damage in the dinoflagellate and this biocide could be effectively used for the control of algal blooms.

• Journal of the Korean Ceramic Society
• /
• v.24 no.4
• /
• pp.397-403
• /
• 1987

Pb(Zr0.52Ti0.48)O3 powders were prepared by hydrothermal synthesis. Using soluble salts such as Pb(NO3)2, TiCl4 and ZrOCl2$.$8H2O and oxide such as PbO and TiO2 as starting materials, PZT powder was hydrothermally synthesized at the temperature range between 150$^{\circ}C$ and 200$^{\circ}C$. The result showed that reactivity by alkali was decreased in the sequence of Pb(NO3)2, TiCl4, ZrOCl2, PbO, TiO2 and ZrO2. Using the first three soluble salts, PZT powder was synthesiged at 150$^{\circ}C$ for 1hr. In PbO-TiCl4-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 8rs. In Pb(NO3)2-TiO2-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 16hrs, in PbO-TiO2-ZrOCl2 system, the powder was synthesized at 200$^{\circ}C$ for 8hrs.

• Environmental Analysis Health and Toxicology
• /
• v.16 no.2
• /
• pp.67-74
• /
• 2001

In a previous study by Kim et al. (2000), sodium hypochlorite (NaOCl) has been demonstrated to be effective against algae that cause red tides. To secure the environmental safely of the chemical in practical use, effect of NaOCl, at concentrations required for algicidal activity, on the histology of rockfish and little neck clam was examined. When the animals were exposed to NaOCl at concentrations of 0.5 or 2ppm for 1 hr, there was no exposure-associated histological change in either animal. As the experimental exposure condition was set in consideration of the use, our results provide safety information necessary for practical application to marine fields.

• Elastomers and Composites
• /
• v.52 no.1
• /
• pp.9-16
• /
• 2017

Graphene-$BiOCl/Fe_3O_4$ nanocomposites were synthesized from $BiOCl/Fe_3O_4$ and graphene in an electric furnace operating at $700^{\circ}C$ for 12 h. The nanocomposite surface morphology and crystal structure were characterized by scanning electron microscopy and X-ray diffraction. The produced graphene-$BiOCl/Fe_3O_4$ nanocomposites acted as efficient heterogeneous photocatalysts for the degradation of organic dyes, as confirmed by UV-vis spectrophotometry.

• Restorative Dentistry and Endodontics
• /
• v.15 no.1
• /
• pp.187-200
• /
• 1990

The purpose of this study was to investigate antimicrobial effect of several irrigation solutions on 7 anaerobes and 2 aerobes, which are found frequently in infected root canals. The antimicrobial effects of normal saline, 3% $H_2O_2$, 0.5% & 3.5% NaOCl, 10% & 50% citric acid and mixed solutions of 3% $H_2O_2$ plus 3.5% NaOCl were compared. No. 80 paper points dipped in bacterial broth were soaked in each irrigation solutions and moved into thioglycolate broth, subcultured in agar plate for bacterial growth. The results were as follows: 1. Normal saline had no antimicrobial effect. 2. Mixed solutions of 3% $H_2O_2$ plus 3.5% NaOCl, 10% citric acid had relatively weak antimicrobial effect. 3.3% $H_2O_2$, 50% citric acid, 0.5% NaOCl showed relatively strong antimicrobial effect. 4. 3.5% NaOCl had the strongest antimicrobial effect among used 7 irrigation solutions.

• Korean Aquaculture
• /
• v.19 no.1
• /
• pp.52-57
• /
• 2007

Chum salmon의 알이 부화하는 동안 물곰팡이의 감염으로부터 보호하기 위해 알을 10 mg/L 염소농도의 하이포아염소산나트륨(NaOCl) 용액에 매일 15분간 수정란에서부터 발안기까지 처리하였다. 감염된 알의 수 및 발안기 알의 수는 부화 23일째 관찰하였다. 전체의 알에서 감염된 알의 비율은 대조구(11.3;59.3%)보다 NaOCl 처리한 실험구(1.8; 33.4%)에서 유의적으로 낮게 나타났다(P<0.01). 전체 알에 대한 발안란의 비율은 대조구(66.1:97.5%)보다 NaOCl처리한 실험구(85.9:98.6%)에서 유의적으로 우수한 경향을 보였다(P<0.01). NaOCl의 항균 활성은 알의 생존율을 향상시킨다. 따라서 NaOCl는 chum salmon의 난에 대한 물곰팡이의 감염에 대하여 아주 유용한 항균물질이라고 판단된다.

• Journal of Magnetics
• /
• v.21 no.2
• /
• pp.179-182
• /
• 2016

In this paper, 10 nm $Fe_3O_4$ nanoparticles were modified on the surface of $2{\mu}m$ flower-like bismuth oxychloride (BiOCl) spheres by a facile co-precipitation method. The results showed that the $Fe_3O_4/BiOCl$ nanocomposites exhibited excellent photocatalytic activity and superparamagnetic property ($M_s=3.22emu/g$) under visible light for Rhodamine B (RhB) degradation. Moreover, the $Fe_3O_4-BiOCl$ photocatalyst possessed magnetic recyclable property, which could maintain high photocatalytic effective even after 20 cycle times. These characteristic indicates a promising application for wastewater treatment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.444-446
• /
• 2010

It has been so many XML applications by development of Web. Also, it keeps going to sore and manage them in object-oriented methods. It is widely used methods using UMLamong them. There are several software to support UML which has diagrams and generates object oriented code easily.It is proposed framework to map from various XML applications to UML/OCL for supporting efficient object based management of Web documents.

• The KIPS Transactions:PartD
• /
• v.10D no.6
• /
• pp.971-982
• /
• 2003

The consistency of UML diagrams is a nature for checking whether diagrams are coherently designed with only one requirements and the correctness of UML Diagrams, especially it uses OCL(Object Constraint Language) which is standard constraint language in UML. Firstly we devise metamodels that are described with conponent and relationships, then we derive verification rules from each matamodels for verifying correctness and consistency, and then we formally specify the rules with OCL for automatic verification. Finally we verify the rules with USE TOOL.