• Journal of Technologic Dentistry
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• v.34 no.2
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• pp.75-81
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• 2012

Purpose: All ceramic crown, made from zirconia instead of metal for core material, is recognized the best esthetical prosthesis. Recently, high-priced zirconia blocks and expensive CAD/CAM machines come into use for making zirconia core. In this study, slip casting process is adapted to evaluate the possibility of the recycling the remained parts of zirconia block after machining. Methods: Remained zirconia blocks were reduced to powders with zirconia mortar, and screened with 180 mesh sieve. Passed powders were ball milled under various conditions to obtain the optimum zirconia slip for casting. Solid casting method was used for casting the specimens with plaster mold. Formed specimens were dried and biscuit fired at $1,000^{\circ}C$ for 1 hour. Biscuit fired specimens were finished with exact shape of square pillar. Finished specimens were fired from $1,200^{\circ}C$ to $1,550^{\circ}C$ at $50^{\circ}C$ intervals for 1 hour. Linear shrinkage, apparent porosity, water absorption, bulk density, and flexural strength were tested. Microstructures were observed by SEM. Results: Above examinations indicated that the optimum firing temperture was $1,500^{\circ}C$, and when fired at this temperature for 1 hour, apparent porosity was 0% and flexural strength was 680MPa. SEM photomicrographs showed uniform 200~300nm grain size, which is equal with microcture of sintered commercial zirconia block. when compare 24% linear shrinkage of cast specimen with 20% linear shrinkage of CAD/CAM machined block, it was estimated that the size controlling of cast core was not so difficult. Conclusion: According to the all of this experimental results, the cast zirconia core produced from the remained parts of zirconia block was possible to use for all ceramic denture.

• Journal of Technologic Dentistry
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• v.40 no.1
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• pp.17-25
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• 2018

Purpose: When casting of ceramics, proper amount of deflocculant was added for disperse the particles in slip. In this study, examined the optimum amount of APMA(ammonium polymethaacrylate) water as deflocculant for casting the zirconia. Methods: The 100 g of zirconia powder were ball milled with 300 g zirconia ball, 90 g of distilled water, and APMA water in polyethylene pot for 24 hours. The amount of APMA water were added as deflocculant from 0.5 to 0.9 g at an intervals of 0.1 g. The viscosity of slip with no deflocculant showed 1362c.p. and the minimum viscosity with 580c.p. obtained when the slip contained 0.7% of deflocculant. Bar type specimens were casted with plaster mold and biscuit fired at $1100^{\circ}C$ for 1 hours. Biscuit fired specimens were finished with $60mm(L){\times}14mm(W){\times}10mm(H) bar$. Finished specimens were 2nd fired at $1500^{\circ}C$ for 1 hour. Results: Regardless the addition of deflocculant, all 2nd fired specimens showed 0% of apparent porosity and water absorption. The specimens with no deflocculant showed 24% of drying shrinkage and 27.4% firing shrinkage. On the other hand, The specimens with deflocculant showed 17.4% of drying shrinkage and 17.6% firing shrinkage regardless the amount of deflocculant. The maximum bulk density with $6.09g/cm^3$ obtained when the specimens casted with 0.7~0.9% of deflocculant contained slips. Bend strength of specimen with no deflocculant showed 680 MPa and the maximum bend strength with 814 MPa obtained when the specimen casted with 0.7% of diflocculant contained slip. Conclusion : It was found that the particle shape of the powder according to the dispersing agent is added, the particle size, sintering temperature and affect the particle size distribution, sintering time, sintering atmosphere, such a great influence on the sintering.

• The Korean Journal of Applied Statistics
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• v.31 no.6
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• pp.835-842
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• 2018

The so-called sliced average variance estimation (SAVE) is a popular methodology in sufficient dimension reduction literature. SAVE is sensitive to the number of slices in practice. To overcome this, a fused SAVE (FSAVE) is recently proposed by combining the kernel matrices obtained from various numbers of slices. In the paper, we consider practical applications of FSAVE to large p-small n data. For this, near-infrared spectroscopy of biscuit dough data is analyzed. In this case study, the usefulness of FSAVE in high-dimensional data analysis is confirmed by showing that the result by FASVE is superior to existing analysis results.

• Nutrition Research and Practice
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• v.17 no.1
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• pp.91-102
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• 2023

BACKGROUND/OBJECTIVES: This study examines life stress, dietary attitudes, and snacking frequency for college students living in Seoul and Gyeonggi Province. The purpose of this study is to assist college students feeling stressed by offering desirable dietary attitudes and choices of the appropriate snacks by providing educational materials that offer appropriate nutrition education and nutritional information. SUBJECTS/METHODS: A survey was conducted on a total of 600 college students aged 19-29-year-olds living in Seoul and Gyeonggi Province (234 male students and 366 female students). Collected data were analyzed using SPSS WIN 28.0 program. RESULTS: Life stress among college students did not differ significantly between the genders. Male students were more stressed about lover (P < 0.01), while female students were more stressed about value problems (P < 0.01) and future problems (P < 0.05). Dietary attitude ratings were 3.1 for both male and female students with no significant difference. The overall snacking frequency was 4.1 times/day-4.2 times/day for male students and 4.0 times/day for female students-thus, there was no significant difference. Male students consumed 'beverage' (P < 0.01) more frequently than female students. Life stress and snacking were positively correlated for 'biscuit/cookie,' 'chip,' 'cereal,' 'juice/smoothie,' 'café americano,' 'café latte,' 'tea,' 'jelly,' 'chocolate,' 'rice cake,' 'milk,' 'flavored milk,' and 'ice cream' among male students. Among female students, life stress and snacking were positively correlated with 'cereal,' 'caramel,' and 'soymilk,' and negatively correlated for 'biscuit/cookie' and 'carbonated drink.' CONCLUSIONS: College students should manage their stress by identifying its causes and learning how to deal with stressful situations. Additionally, providing them with proper nutrition education based on the correct nutritional information is essential for promoting good food attitudes and snacking behaviors.

• Animal cells and systems
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• v.2 no.1
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• pp.9-20
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• 1998

Two new species, Pentathyone kojinensis n. sp. and Pseudocnus pawsoni n. sp. belonging to the families Sclerodactylidae and Cucumariidae are described. In addition, four species, Thyone bicornis, Thyone fusus chinensis, Thyone micra, and Molpadia changi, are reported as new records from Korea. Pentathyone kojinensis n. sp. closely resembles Cucumaria mirabilis Theel and C. constrica Ohshima in ossicle form, but the latter two species are clearly distinguished from the new species in having the posterior processes of the calcareous ring in several fragments, rather than stout and entire. Pseudocnus pawsoni n. sp. is similar to Cucumaria koraeensis Ostergren in general features and ossicle morphology though it has not biscuit-shaped plates. However, Cucumaria koraeensis has ten tentacles of the same size, unlike Pseudocnus pawsoni n. sp. in which the two ventral tentacles are much smaller than the remaining eight.

• The Journal of the Korean dental association
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• v.16 no.5 s.108
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• pp.391-394
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• 1978

The authors had surveyed on the snack foods of 300 primary school children in Seoul in order to obtain the informations for the dietary counseling and suggestions as a method of dental caries prevention. The obtained results were as follows; 1. Primary school children had the intake of the snack foods in the order of the apple, the candy, the orange, the cake, the milk, the biscuit, the Ramyeontang, the regular gum, the persimon, the Tugpokie. 2. Of the primary school children, 5.6% had intaking no snack food, but 10.6% once, 21.6% twice, 29.0% three times, and 33.0% four times or over in a day, respectively.

• Korean Journal of Child Studies
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• v.26 no.6
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• pp.161-171
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• 2005

In Experiment 1, 4- and 5-year-olds were shown either continuous(i.e., pizza) or discontinuous Stimuli(i.e., biscuit) by the experimenter. After a proportion(e.g., 2/8, 4/8, or 6/8) was removed, children were asked to remove an equivalent proportion. Whereas 4-year-olds proportional reasoning was correct only when they shared the same stimulus with the experimenter, 5-year-olds reasoned correctly regardless whether or not they shared the stimulus with the experimenter. In Experiment 2, where the discontinuous stimulus was changed, 4-year-olds also made correct proportional reasoning even when their stimulus was different from the experimenter's. Contrary to other studies, quantity didn't affect children's proportional reasoning except the proportion 1/4, where problems with discontinuous quantity were solved more successfully than problems with continuous quantity.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.13-17
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• 1994

The purpose of this study was to show the abnormal eating habit in pervasive development disorder (PDD) children. The authors studied retrospectively the features of eating habit in 60 PDD children diagnosed by DSM-III-R who made their first visity to Department of Psychiatry, Dongsan Medical Center Keimyung University, from January 1990 to December 1990. The results were as follows;1. The average was 3 years, onset age of illness was before 3 years of all patients, and the ratio between male and female was 5,7:1, and ratio between autistic disorder and PDDNOS was 4:1. 2. Twenty four of 60 PDD children had one or more abnormal eating habit(autistic disorder; 43.8%, PDDNOS; 25%), and more prevalent to male(43.1%,) than female(22.2%). 3. Milk, biscuit, meat and fluids were the favorate foods, the unfavorate foods were vegetable, rice, frutis. 4. Patients of abnormal eating habit were more symptoms of DSM-III-R on 'lack of awareness', 'preoccupation with parts of objects','distress over change'and 'insistence on routine' than others.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.106-114
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• 2019

The study was conducted to investigate the effect of whole-wheat ratio and nutrition information provision on purchasing behavior and consumer intention among individuals in their twenties who lack calcium intake. In the end, this study aims to provide basic data on the development and marketing strategy of customized nutrition-reinforced snacks. Regarding whole wheat ratios, the acceptance of taste of whole wheat flour was highest in ZF but didn't seem significant difference with HF's. The familiarity of taste and flavor (P <0.001), purchase intention (p <0.001) and recommendation intention (p <0.001) were higher in order of ZF, HF and TF. Regarding information provision, familiarity of taste and flavor (P <0.05), purchase intention (p <0.05) and recommendation intention (p <0.05) were higher in order of detailed information group, non - information group and simple information group. Therefore, developing calcium-fortified biscuit, mixing whole wheat flour with normal flour might reduce consumer's resistance, Also, providing detailed information on the degree of fortification of calcium and dietary fiber might cause a synergistic effect on consumption.

• Animal Systematics, Evolution and Diversity
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• v.23 no.1
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• pp.35-38
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• 2007

Two new sponges, Euryspongia coreana n, sp, and E. regularis n, sp., collected from Hataedo, Ulleungdo and Chujado, Korea by SCUBA diving during the period from 2001 to 2005. Euryspongia coreana n. sp, is very close to E. lactea Row, 1911 and E. arenaria Bergquist, 1961 in skeletal structure, but primary and secondary fibres of the new species are thicker than those of E. lactea, E. arenaria is cored with mostly spicule fragments but E. coreana n. sp. is cored with mainly sand. E. regularis n. sp. is readily distinguished from other eurypsongian sponges. by its thickly encrusting growth form, yellowish ivory colour, and thickness of fibres. The bright yellow color and regular ladder-like skeletal structure are major features distinguishing this E. regularis n. sp. from other euryspongian sponges. Most species are brown, violet, red or orange in color except for E. lactea (milky white), E. arenaria (biscuit) and E. coreana n. sp. (yellowish ivory). Other euryspongian sponges have regularly or irregularly well developed secondary fibres, but E. regularis n. sp. has simple and regular secondary fibres.