• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.355-359
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• 2002

This study was carried out to investigate the combined effect of cold storage with irradiation on rooting of chrysanthemum cuttings. Each cutting was six cm in length with three real leaves. A set of Groups of the cuttings was irradiated with 0 to 70Gy of gamma-ray after four weeks of cold storage, while another groups were irradiated with the same doses and then stored at $4^\circ{C}$ for four weeks. Root and shoot growth were observed at 15 and 20 days after planting of the cuttings in a Plug tray. Accelerated root formation was observed in 30 Gy irradiated group, and root growth was also enhanced in 20 and 30 Gy irradiated groups 20 days after planting. In case of irradiation combined with pre-treatment of cold storage, survival rate of cuttings was the highest (80%) in 30 Gy irradiated group. The groups treated with irradiation first before cold storage were apparently better in root formation, among which 50 Gy irradiated group showed the highest rate of root growth.

• Journal of Families and Better Life
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• v.33 no.4
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• pp.33-50
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• 2015

The purpose of this study was examining the effects of family sandplay therapy with structural family therapy in improving the family strengths of children with emotional and behavioral disorders. First, we looked for a way to combine family sandplay therapy with structural family therapy and formulated an approach that could maximize the strengths of each theory and complement each other's weaknesses. And then we applied family sandplay therapy together with structural family therapy and analyzed its effects on family strengths. The subjects of this study were 10 families of children with emotional and behavioral disorders, and they were divided into an experimental group with 5 families and a control group with the other 5. To the experimental group received 16 sessions of family sandplay therapy with structural family therapy. In order to prove the effectiveness of family sandplay therapy with structural family therapy on family strengths, a family relationship( husband-wife relationship, parent-child relationship, and sibling relationship) scale and a family function(family cohesion, family adaptability) scale were used. The main findings of this study are as follows. First, the family relationships of the families with emotional-behavioral disorder children were improved after the application of family sandplay therapy with structural family therapy. Second, the application of family sandplay therapy with structural family therapy improved the family function of families with emotional-behavioral disorder children. Third, in the course of family sandplay therapy with structural family therapy, family sand tray was changed in a pro-healing direction, and family structure was also transformed from a dysfunctional structure to a functional one. As previously stated, family sandplay therapy with structural family therapy for families of children with emotional and behavioral disorders enhanced family strengths through improving family relationships and restoring family functions.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.850-868
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• 1996

The accuracy and dimensional stability of impression materials are one of the most important factors for successful prosthodontic treatment. The purpose of this study was to evaluate the accuracy of several dental elastomeric impression materials used widely and clinically : Impregum-$F^{(R)},\;Permlastic^{(R)},\;Silascon^{(R)},\;Perfect^{(R)},\;Xantopren^{(R)}$. There have been many studies to evaluate the accuracy of impression materials. But it has not been decided yet, which method was most suitable for the evaluation of the accuracy. In this study, two resin teeth, #15 & 25, were prepared with rounded shoulder margin and 90 degree cavosurface angle. For the polysulfide rubber and polyether, the custom tray was made at least 24 hours prior to impression taking. For the silicone rubber materials, putty/wash impression technique was applied in taking impressions. Marginal openings of the castings on the master dies and prepared resin teeth were measured under stereomicroscope. The results were statistically analyzed and compared between tested impression materials. The results were as follows ; 1. In the overall accuracy of impression materials, polyether was the most accurate one, followed by polysulfide, additional silicone and condensation silicone. 2. On the first model pouring, condensation silicone had the largest discrepancies and there was significant difference compared to the other impression materials. 3. Polysulfide had the least discrepancies in the first model pouring, but showed larger discrepancies in the immediate second pouring than the first pouring. 4. On the immediate second pouring, the discrepancy of polyether was shown to be the smallest, while the largest one was additional silicone. 5. Polyether and polysulfide rubber using custom impression trays showed superior accuracy to silicone rubber, putty/wash impression technique.

• Journal of Periodontal and Implant Science
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• v.28 no.1
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• pp.177-185
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• 1998

Periodontal disease and/or loss of teeth brings pathologic tooth migration that can result in esthetic and occlusal problems. Diastema and general spacing of the teeth, particularly in the anterior segments of the dentition are frequently developed in individuals with advanced periodontal disease. Thus, the overall treatment plan for a patent with advanced periodontal disease often involves periodontal orthodontic combined therapy. Orthodontic treatment in adults with periodontal disease is restricted to tooth alignment with special caution. Indirect bonding can achieve accurate bracket placement. A 38 year old woman with adult periodontitis was treated by periodontal therapy. Subsequently, her diastema was orthodontically corrected by indirect bonding technique. It must be an appropriate case report of periodontal-orthodontic combined therapy.

• Journal of Technologic Dentistry
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• v.39 no.3
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• pp.137-143
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• 2017

Purpose: The purpose of this study is to analyze the fitness of heat - pressed ceramic laminate veneers fabricated using the additive manufacturing. Methods: Impression was replicated by using light body silicone and heavy body silicone on the custom tray, and it was fabricated using Type IV Stone. The test specimens were prepared by using a dental scanner, a laminating veneer using a dental design program, and a specimen with a 3D printer. The control specimens were prepared by the lost wax technique and heat - pressed to fabricate the specimens. The data of the specimens were measured by the RMS value of the internal fitness a using a 3-dimensional measurement program. Results: The Stereolithography laminate veneer group was measured at $78.10(4.09){\mu}m$ and the LWV group was measured at $31.50(5.10){\mu}m$. There is a significant difference between the two groups (p<0.001) Conclusion : Evaluation of fitness laminate veneers was fabricated by additive manufacturing showed the difference statistically significantly and clinically acceptable result.

• Korean Journal of Agricultural Science
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• v.40 no.3
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• pp.197-202
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• 2013

This study was aimed to find the storage potential of low temperature adapted shiitake mushroom under freezing temperature ($-3^{\circ}C$). Fresh shiitake mushroom was harvested at late Feb. and cooled to target temperature, $-3^{\circ}C$ in the cooling room for 24 hr. Cooled mushroom were then placed in plastic boxes, wrapped with plastic film ($30{\mu}m$), and stored at $-3^{\circ}C$ for 2 months. Weight loss of mushroom was ranged from 2.1 to 3.2%. Dry weight per unit fresh weight, however, was slightly increased because of moisture loss. Firmness of fruit body increased from $0.95kg/cm^{-2}$ (before storage) to $1.13kg/cm^{-2}$ (after 2 month storage). About half amount of starch was lost during 2 month storage. The amount of total and reducing sugars remained relatively constant. After storage, freshness of mushroom was recovered by thawing treatment. When recovered mushroom were packaged with styrofoam tray and PVC wrapping, and exposed to ambient and $10^{\circ}C$, respectively, brown spot on the gill of fruit body was found and slight decay symptom was also found at ambient temperature only but not at $10^{\circ}C$. Results indicated that low temperature adapted shiitake mushroom has a storage potential under freezing temperature ($-3^{\circ}C$). Freezing storage technology of fresh shiitake mushroom will contribute the increase of storability up to 2 months.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.590-595
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• 1994

Kimchi packed in PP tray was stored at $10^{\circ}C$ to investigate the effect of filling ratio on the quality changes. The quality of Kimchi studied were gas composition in the package, pH, titratable acidity, color, growth of lactic acid bacteria and sensory properties. As the filling ratio increased, there was more $O_{2}$ consumption and $CO_{2}$ evolution measured. Titratable acidity and pH were not significantly affected by the filling ratio. Color change of crushed Kimchi juice was also little affected by the filling ratio. During the storage, L and b values were decreased exponentially, but a value s remained constant. The growth of lactic acid bacteria and sensory scores showed no significant difference according to the filling ratio. Therefore, the filling ratio in packaging of Kimchi seemed to have little influence on the quality changes of Kimchi.

• Atmosphere
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• v.26 no.1
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• pp.73-84
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• 2016

A method to make ice spike using home refrigerator with ice tray was found. Many experiments have carried out with this method and many natural phenomena occurring on the formation of ice spike are found. A new concept of the Latter Freezing Water (LFW) was imported to explain the ice spike formation. At LFW position on water surface, the Sprout of Super cooled Water (SSW) grows by the Volume Expansion Effect (VEE) caused by the phase change of water in water. And air bubbles that are expelled from ice during freezing process, gather, rise, and detonate at the upper most part of SSW that make SSW freeze and grow upward with the water pipe in it. Together with VEE the capillarity in the water pipe makes the column grow more, that makes the ice spike. Many other findings were succeeded; 1) Ice spike process is completed before the whole water freezes. 2) If water is corrupted or shocked, even though it is very slight, ice spike is not generated. 3) Rain water contains the most LFW among all kind of waters used in experiments. 4) LFW is changed into normal water after passing the ice spike. 5) A new concept of the ice bullet is introduced. 6) The reason of frequent occurrences of the ice spike at Mt. Mai is investigated also.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.539-544
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• 1998

Thermoformed appliance, which has been recently introduced for dental usage, is an appliance made of thermoformed sheets and formed with positive or negative pressure under heat. Thermoplastic material is a kind of plastics and can be repeatedly softened by heat. It is classified into hard elastic foil, hard/soft compound foil and soft elastic foil, including BIOPLAST, BIOCRYL, IMPRELON, etc. It has been developed in 1969 and is available in various thickness, shape and color. There are two types of Vacuum former for thermoplastic materials; the pressure type and suction type. The former is much better than the latter for fabrication of various appliances due to its higher pressure. The authors have applied these appliances to some cases - chin cap, active retainer, individual Fluoride tray, mouth protector, bracket transfer mask, bruxism splint(night guard), Essix appliance - by pressure type Vacuum former($Biostar^{(R)}$). The thermoplastic appliances have numerous advantages such as simple procedure, short working time, clean and transparent product, less objectionable taste. But its outstanding advantage would be its excellent biocompatibility bacause it has no monomer and hence no tissue irritation. Although there is some limitations in its usage, it can be used widely for various purposes especaily for pediatric dentistry.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.351-355
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• 2007

It is necessary to convert butene-2 into butene-1 with higher added-values through positional isomerization. In this study, hydro-isomerization of butene-2 with hydrogen over Pd/alumina catalysts was investigated in a fixed bed reactor. The yield of butene-1 over Ld-265 catalyst was higher than that over other catalysts. The yield of butene-1 was highest (5.3%) under the conditions of reaction temperature of $75^{\circ}C$, reaction pressure of 150 psig, 2-butene flow rate of 48 cc/h and hydrogen flow rate of 3 cc/min. We conducted simulation for the process composed of a hydro-isomerization reactor and a distillation tower. In the case of 78% of tray efficiency, we obtained over 99% pure butene-1 through a distillation tower with 171 steps (R=120).