• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.21-29
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• 2004

Statement of problem : Because dental impression can be a cross-infection source, disinfection, such as immersion disinfection is nessecary. However, the disinfection process may change the volume of the impression cast. Purpose : The purpose of this study is to find out the effects on dimensional change of different storage times and methods, of agar-alginate impression when immersed in a 5% idophor disinfectant. Material and Methods : An agar-alginate impression was made from a mandible model and then was disinfected and stored according the experimental conditions and a stone model was produced. Measurements were taken between reference points on the original mandible model and they were compared to measurements taken between reference points on the stone model. The study was divided into 4 groups. In group 1, the impression was stored in a 100% humidor for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 12 hours and 24 hours and stone models were made at each time. In group 2, the impression was immersed in 5% idophor disinfectant and then stored in a 100% humidor for the same length of times as group 1, and stone models were made at each time. In group 3, the impression was stored in extend-A-pourR, a special storage solution for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 12 hours, 24 hours 3 days, and 7 days and stone models were made at each time. In group 4, the impression was immersed in 5% idophor disinfectant and then stored in stored in extend-A-pourR, a special storage solution for the same length of times as group 3, and stone models were made at each time. 5 impressions and stone models were made at each time to make a total of 180. The Student-t test (P < .05) was used to do a statistical analysis of the measurements of the mandible model and stone models. The repeated-measure 2-way analysis of variance (P < .05) was used to do a statistical analysis of the difference in the 4 groups. Results : The percent liner dimensional change was from $0.25{\pm}0.03%$ (group 1, 30 minutes) to $0.34{\pm}0.06%$ (group 4, 7 days). No significant change was noticed between the 4 groups. Conclusion : According to the above study, in both methods, least dimensional change was recorded when the storage times were short and in both methods, immersion in 5% idophor disinfectant did not effect dimensional change in the agar-alginate impression.

• Korean Journal of Materials Research
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• v.30 no.8
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• pp.383-392
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• 2020

In this paper, AgCl/Ag₃PO₄/diatomite photocatalyst is successfully synthesized by microemulsion method and anion in situ substitution method. X-ray diffraction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) are used to study the structural and physicochemical characteristics of the AgCl/Ag₃PO₄/diatomite composite. Using rhodamine B (RhB) as a simulated pollutant, the photocatalytic activity and stability of the AgCl/Ag₃PO₄/diatomite composite under visible light are evaluated. In the AgCl/Ag₃PO₄/diatomite visible light system, RhB is nearly 100 % degraded within 15 minutes. And, after five cycles of operation, the photocatalytic activity of AgCl/Ag₃PO₄/diatomite remains at 95 % of the original level, much higher than that of pure Ag₃PO₄ (40 %). In addition, the mechanism of enhanced catalytic performance is discussed. The high photocatalytic performance of AgCl/Ag₃PO₄/diatomite composites can be attributed to the synergistic effect of Ag₃PO₄, diatomite and AgCl nanoparticles. Free radical trapping experiments are used to show that holes and oxygen are the main active species. This material can quickly react with dye molecules adsorbed on the surface of diatomite to degrade RhB dye to CO₂ and H₂O. Even more remarkably, AgCl/Ag₃PO₄/diatomite can maintain above 95 % photo-degradation activity after five cycles.

• The Korean Journal of Mycology
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• v.45 no.2
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• pp.91-101
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• 2017

Three species of powdery mildew (Erysiphales) on eggplant (Solanum melongena L.) have been listed in Korea, namely Erysiphe cichoracearum (now genus Golovinomyces), Leveillula taurica, and Sphaerotheca fusca (now genus Podosphaera; syn. Podosphaera xanthii). Since E. cichoracearum was recorded on eggplant for the first time in Korea in 1969, it has been regarded as a major powdery mildew agent on that plant. In 1998, the causal agent of powdery mildew on eggplant was recorded as L. taurica, then as S. fusca in 2002. During our extensive field surveys in Korea, we collected 22 samples of eggplant powdery mildews. Our microscopic observations and molecular sequence analyses showed that all of our samples belonged to the genus Podosphaera, in the absence of either E. cichoracearum or L. taurica, suggesting that P. xanthii is the dominant agent of powdery mildew disease on eggplants in Korea. As there have been no additional findings on L. taurica after the first report on the species, it seems to be a minor species that is rarely found in greenhouses. The presence of E. cichoracearum (syn. Golovinomyces cichoracearum s. lat.) on eggplants is questionable, as the morphological characteristics of E. cichoracearum in the original description of the Korean collection deviate from the morphological variations of this species. In addition, no herbarium material of E. cichoracearum remains. Consequently, it seems that P. xanthii is the main species of powdery mildew on eggplants, whereas L. taurica occurs rarely on eggplants, in Korea. This review provides the historical and recent taxonomy of eggplant powdery mildews in detail.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.6
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• pp.896-902
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• 2010

Omija contains high organic acid content (5~7%) that must be reduced in order to produce high quality wine for consumption. In this study, we used pear, which has low total acid but plenty of sugar, to relieve the sourness of Omija material. Our group mixed Omija and pear at a ratio of 1:9 to 1:15 in order to attain a 0.5~0.7% total acid level, similar to commercial wine. As Omija was mixed with pear, the red color of Omija changed to a lighter red color. Alcohol fermentation solution of Bokbunja and Gaeryangmeoru were used to make up for the light red color of Omija pear wine. The red color of Bokbunja was confirmed to be similar to the original red color of Omija. It was proven that addition of 3~5% Bokbunja to Omija pear mixture wine produced replicated the red color image of Omija. Our results show that addition of 2~5% xylitol to Omija pear mixture wine was good by sensory test.

• Journal of the Korea Concrete Institute
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• v.14 no.4
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• pp.449-456
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• 2002

Recently, the application of high strength and high performance concrete has been gradually increased as an important construction material for high rise and huge scaled construction. However, high performance concrete has undesirable characteristics of spalling subjected to high temperature due to its dense microstructure content. A spalling by fire brings surface failure and falling off concrete member. It is considered that spalling by fire should be taken into account for the safety of the concrete structure under fire. Therefore, in this paper, tests are carried out using high performance concrete containing polypropylene(PP) fiber in order to improve the fire resistance performance. PP fiber contents and member sizes are varied. According to experimental results, as for the influence of PP fiber contents, all the test specimens without PP fiber show entire failure in W/C of 35％, while they show nearly sound shape except some kinds of surface fracture in W/C of 55％. When PP fiber is contained more than 0.07％, favorable prevention effects of spatting by fire are obtained. As for the effects of test specimens size, it tends to increase the possibilities of spatting by fire as test specimens become larger. And spatting by fire at the edge of test specimens occurs more frequently than at the surface of test specimens. Residual compressive and tensile strength shows 45∼65 ％ of its original strength at W/C of 35％, and 30∼40％ at W/C of 55 ％.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.389-394
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• 2016

Background: Tetrahedral-mesh geometries can be used in the MCNP code, but the MCNP code accepts only the geometry in the Abaqus input file format; hence, the existing tetrahedral-mesh models first need to be converted to the Abacus input file format to be used in the MCNP code. In the present study, we developed a simple but useful computer program, TET2MCNP, for converting TetGen-generated tetrahedral-mesh models to the Abacus input file format. Materials and Methods: TET2MCNP is written in C++ and contains two components: one for converting a TetGen output file to the Abacus input file and the other for the reverse conversion process. The TET2MCP program also produces an MCNP input file. Further, the program provides some MCNP-specific functions: the maximum number of elements (i.e., tetrahedrons) per part can be limited, and the material density of each element can be transferred to the MCNP input file. Results and Discussion: To test the developed program, two tetrahedral-mesh models were generated using TetGen and converted to the Abaqus input file format using TET2MCNP. Subsequently, the converted files were used in the MCNP code to calculate the object- and organ-averaged absorbed dose in the sphere and phantom, respectively. The results show that the converted models provide, within statistical uncertainties, identical dose values to those obtained using the PHITS code, which uses the original tetrahedral-mesh models produced by the TetGen program. The results show that the developed program can successfully convert TetGen tetrahedral-mesh models to Abacus input files. Conclusion: In the present study, we have developed a computer program, TET2MCNP, which can be used to convert TetGen-generated tetrahedral-mesh models to the Abaqus input file format for use in the MCNP code. We believe this program will be used by many MCNP users for implementing complex tetrahedral-mesh models, including computational human phantoms, in the MCNP code.

• The Journal of the Korean dental association
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• v.48 no.4
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• pp.280-287
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• 2010

Objective: In spite of increasing dental treatment for the disabled, there was a few collected data on dental treatment status and dentists' perception in Korea. The purpose of this' study is to research the current dental treatment status for the disabled in Korea and to suggest public health policies for the disabled. Material and methods: Total of 68 dentists who have treated the disabled regularly were asked to fill questionnaires regarding dental treatments for the disabled. Results: 1. It is necessary to set up public dental center for the disabled in rural area. 2. In case of dental treatments relating to cerebral palsy, ADHD, autism, the compensation for treatment time and extra investment is needed. 3. Only 39.7% of dentists charged treatment fees to the disabled as same as normal patients. Moreover 38.2% of dentists answered that they didn't charge treatment fees at all when their patient are disabled. 4.23.5% of dentists provided all of dental treatments including dental implant and orthodontic appliances in Korea. However, 54.3% of dentists reported the improvement of access to dental implant, orthodontic and esthetic treatment is needed. 5. It is imperative for the government to improve the support system for the disabled. Conclusions: Through this research only 26.5% of dentists answered that they had received the fund from the government and 11.1% of them were satisfied with the support for the disabled in Korea. This indicated the improvement of government financial support system for the disabled is needed.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.58-66
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• 1998

Purpose : This paper introduces a new three dimensional magnetic Resonance Image classification which is based on Mar kov Random Field-Gibbs Random Field with a line model. Material and Methods : The performance of the Gibbs Classifier over a statistically heterogeneous image can be improved if the local stationary regions in the image are disassociated from each other through the mechanism of the interaction parameters defined at the local neighborhood level. This usually involves the construction of a line model for the image. In this paper we construct a line model for multisignature images based on the differential of the image which can provide an a priori estimate of the unobservable line field, which may lie in regions with significantly different statistics. the line model estimated from the original image data can in turn be used to alter the values of the interaction parameters of the Gibbs Classifier. Results : MRF-Gibbs classifier for volumetric MR images is developed under the condition that the domain of the image classification is $E^{3}$ space rather thatn the conventional $E^{2}$ space. Compared to context free classification, MRF-Gibbs classifier performed better in homogeneous and along boundaries since contextual information is used during the classification. Conclusion : We construct a line model for multisignature, multidimensional image and derive the interaction parameter for determining the energy function of MRF-Gibbs classifier.

• Journal of Adhesion and Interface
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• v.13 no.1
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• pp.17-23
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• 2012

A fragrant microcapsule was prepared for use by students to reduce the stress of taking examinations. Rosmarinic acid was used as a fragrant oil which had the effect of relaxing stress, polycaprolactone (PCL) was used as a capsule wall material, and poly(vinyl alcohol) (PVA) as a stabilizer. The solvent evaporation method was used to form the microcapsule. The microcapsules were prepared by changing the stirring rate, the concentration of the stabilizer, and the molecular weight of PCL. The shape of the microcapsule was characterized by scanning electron microscopy (SEM). The size of the microcapsule was reduced by increasing the stirring speed. The release rate of rosmarinic acid was decreased when the higher molecular weight PCL was used. When the prepared microcapsule was tested in an aromatherapy class, the microencapsulated fragrant oil had a longer release time than the original fragrant oil. The study data showed that this fragrant oil was effective for increasing concentration ability, reducing stress, increasing digestive power, and increasing memory for the students.

• Food Science and Preservation
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• v.17 no.6
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• pp.763-769
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• 2010

We examined variations in ginger dehydration and recovery rate upon use of dextrose of different equivalence values. The dehydration rate varied with dextrose equivalent and the dehydration rate increased as the equivalence value increased. Both dehydration and recovery rates varied with dextrose molecular weight. Moisture content was lowest in samples prepared by freeze-drying, and neither dextrose equivalent nor molecular weight affected moisture level. Upon color analysis, ginger dried using dextrose varying in equivalence and molecular weight was similar in color to the original material, unlike ginger dried by other methods. Hot-air-dried ginger scored lowest in all sensory tests, compared with ginger prepared by molecular press dehydration using dextrose varying in equivalence and molecular weight. With respect to the appearance of ginger, freeze-dried samples were optimal, but molecular press dehydration yielded samples that scored best upon overall evaluation. When all quality evaluation items were taken together, molecular press dehydration resulted in a better quality product than the older hot-air or freeze-drying methods.