• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.185-192
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• 2020

Purpose: The purpose of this study is to investigate dental students' self-perception of clinical care ability after a denture treatment experience. Materials and methods: Of the 58 fourth-year students at the dental school in 2019, 50 students completed the questionnaire concerning their denture treatment session, including treatment planning and pre-prosthetic treatment (4 questions), clinical and laboratory procedures (20 questions), and students' opinions on clinical denture education (4 questions). Each question was answered on a five-point scale, of which points four and five, "agree" and "strongly agree" respectively, were classified as positive responses while points one and two, "disagree" and "strongly disagree" respectively, were classified as negative. Results: All the items on clinical and laboratory procedures received a positive response rate of over 60%, and the overall self-perception of the students appeared to be positive. However, the questions on the ability to perform denture treatment independently after graduation received only 48% of positive answer. Those on patient management, explanations of denture precautions, customized tray production, boxing, and work model production were answered with the highest positive response rate whereas those on treatment planning, final impression acquisition, and surveying, were the lowest in each session. Conclusion: The dental students with experience in denture treatment generally have a positive opinion of their clinical care ability, but further education may be necessary to improve their ability to treat their patients independently.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.114-120
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• 2010

Conventional surface texturing in crystalline silicon solar cell have been use wet texturing by Alkali or Acid solution. But conventional wet texturing has the serious issue of wafer breakage by large consumption of wafer in wet solution and can not obtain the reflectance below 10% in multi crystalline silicon. Therefore it is focusing on RIE texturing, one method of dry etching. We developed large scale plasma RIE (Reactive Ion Etching) equipment which can accommodate 144 wafers (125 mm) in tray in order to provide surface texturing on the silicon wafer surface. Reflectance was controllable from 3% to 20% in crystalline silicon depending on the texture shape and height. We have achieved excellent reflectance below 4% on the weighted average (300~1,100 nm) in multi crystalline silicon using plasma texturing with gas mixture ratio such as $SF_6$, $Cl_2$, and $O_2$. The texture shape and height on the silicon wafer surface have an effect on gas chemistry, etching time, RF frequency, and so on. Excellent conversion efficiency of 16.1% is obtained in multi crystalline silicon by RIE process. In order to know the influence of RF frequency with 2 MHz and 13.56 MHz, texturing shape and conversion efficiency are compared and discussed mutually using RIE technology.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.2
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• pp.87-92
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• 2011

In order to better understand the role of litter layer on hydrological cycle in forest, we estimated the interception storage capacity of the litter layer at Gwangneung deciduous forest. We first made a thickness map of the litter layer at the study site based on field survey and then collected representative litter samples for the laboratory experiment. We constructed a measurement device consisting of sample tray, drain collector, tipping bucket, and a data logger. Using this device, we examined the relationship between the interception storage capacity ($C_i$) and the thickness (d) of the litter layer. For the range of d from 25 to 100 mm, there was a simple linear relationship between $C_i$ and d, which changed with the intensity of the simulated rain. The results were extrapolated to d smaller than 25 mm by considering that no interception occurs without litter layer. Overall, $C_i$ increased rapidly when d was low (< 25 mm) but the rate of increase decreased as d increased due to clumping. With an average thickness of 59 mm, the estimated $C_i$ at the site was 0.94 (${\pm}0.39$) mm. Such an interception storage capacity of the litter layer is comparable to that of the forest canopy, suggesting that the litter layer can play an important role in the forest water cycle.

• Journal of the Korean earth science society
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• v.30 no.4
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• pp.454-463
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• 2009

In this study, from January 2006 to February 2009, we observed 107 ice spikes formed in a natural state, and analyzed their environment. We developed an experimental device to reproduce ice spikes in laboratory and successfully made 531 ice spikes. We analyzed the process of the formation and the principle of how those ice spikes grow through videotaped data of the formation in the experiment. In the natural world, when the surface of water and the lower part of a vessel begin to freeze, a vent (breathing hole) develops at the surface where an ice is not frozen; this vent serves as the seed of an ice spike. It is assumed that the volume expansion of ice in the vessel which occurs when water freezes makes the supercooled water go upward through the vent and becomes an ice bar called an ice spike. In the laboratory, however, when distilled water is poured into an ice tray cube and kept in the experimental device for about one and a half hours at a temperature of -12- $-13^{\circ}C$, a thin layer of ice then begins to develop on the surface of the water, the vent is formed, and ice spikes form for about 10-30 minutes. These spikes stop growing when the end becomes clogged. Ice spikes can be described as falling into seven categories of shape, with the apex type topping the list followed by the slant type in the natural state and the vertical type predominating in the laboratory.

• Journal of the Korean GEO-environmental Society
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• v.21 no.7
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• pp.5-16
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• 2020

Currently, the seismic design standards have been strengthened due to the occurrence of the Gyeongju and Pohang earthquake, and seismic performance evaluation of existing facilities is being conducted. It aims to secure a seismic performance effect during earthquakes by improving the micro-pile method, which can be constructed in limited confined places while minimizing damage to existing facilities. The improvement method is to construct all the piles in the square-tray-type plate on the top of the pile by constructing the slope pile in the form of an umbrella around the vertical pile, the main pillar. In this paper, the numerical analysis was performed to analyze the horizontal displacement behavior of an umbrella-type micropile for various real-measurement seismic waves in sandy soil. As a result of numerical analysis, the softer the ground, the better the effect of horizontal resistance of umbrella-type micropile. The horizontal displacement reduction effect was pronounced when the embedded depth was 15 m or more at the same ground strength, and it was found to be effective in earthquakes if it was settled on the ground with an N value of 30 or more. The embedded depth and horizontal displacement suppression effect of the micropile was proportional. Generally, the weaker the ground, the greater the displacement suppression effect. Umbrella-type micropile had a composite resistance effect in which the vertical pile resists the moment and inclined pile resists the axial force.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.477-486
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• 1998

In this paper, we implemented the urine analysis system capable of measuring a qualitative and semi-quantitative and assay using strip. The analysis algorithm of urine analysis was adopted a fuzzy logic-based classifiers that was robust to external error factors such as temperature and electric power noises. The spectroscopic properties of 9 pads In a strip were studied to developing the urine analysis system was designed for robustnesss and stability. The urine analysis system was consisted of hardware and software. The hardware of the urine analysis system was based on one-chip microprocessor, and Its peripherals which composed of optic modulo, tray control, preamplifier, communication with PC, thermal printer and operating status indicator. The software of the urine analysis system was composed of system program and classification program. The system program did duty fort system control, data acquisition and data analysis. The classification program was composed of fuzzy inference engine and membership function generator. The membership function generator made triangular membership functions by statical method for quality control. Resulted data was transferred through serial cable to PC. The transferred data was arranged and saved be data acquisition program coded by C+ + language. The precision of urine analysis system and the stability of fuzzy classifier were evaluated by testing the standard urine samples. Experimental results showed a good stability states and a exact classification.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.293-296
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• 2008

This study was carried to select artichoke (Cynara scolymus L.) varieties that can be cultivated in non-heated greenhouse during winter in Jeju Island in Korea. Artichoke varieties namely, 'Purple Romagna' (Neseed Co.), 'Imperial Star' (Keithley Williams Seed Co.), 'Green Globe' (Park Seed Co.), 'Emerald' (Ferry-morse Seed Co.), 'Italian' (Unknown), and 'Carciofo Di Romagna' (Lortolano), were raised in a plug tray with 72 cells for two months and transplanted in a non-heated greenhouse on October 5, 2004. The first harvesting of 'Emerald' and 'Imperial Star' were the earliest and April 26 and 27, 2005 respectively. Most of the varieties were harvested from early May to June 2005. The number of head per plant was the highest in 'Green Globe' with more than five heads and the lowest were recorded in 'Italian' with one head or less. The weight of heads per plant was more than 228 g in 'Purple Romagna', 'Imperial Star' and 'Green Globe'. The highest yield was in 'Green Globe' with 2,172 kg/10a, followed by 'Imperial Star' with 1,947 kg/10a. Accordingly, it is considered that 'Green Globe' and 'Imperial Star' are adequate for the high-yield cultivation in non-heated greenhouse in Jeju Island. They can be harvested from the April to June when cultivated from the early October of the previous year.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.11-15
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• 2009

Commercial tofu was cut and re-packed in a vacuum container, an airtight container and an open tofu tray in an effort to assess the effects of vacuum containers on the shelf life of leftover tofu. The re-packed tofu were stored at $5^{\circ}C$ and $25^{\circ}C$ for the enumeration of total bacteria and coliforms. We also measured changes in color, pH, and opacity. The vacuum retarded the bacterial growth under $10^5$ CFU/mL for up to 12 days at $5^{\circ}C$. The color of the tofu was unaffected by the container type at both storage temperatures, whereas the pH and opacity of the immersion solution were altered less profoundly by storage in the vacuum container at $5^{\circ}C$. However, we noted no significant differences in bacterial growths, pH, and opacity among container types at $25^{\circ}C$. The results of this study showed that the usage of vacuum containers may be a favorable method for the preservation of tofu under refrigerated conditions.

• The Korean Journal of Mycology
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• v.26 no.3 s.86
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• pp.380-386
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• 1998

To obtain basic data for mass production of Isaria japonica, cultural characteristics of japonica were investigated by using liquid, solid media and silkworms pupa. Mycelia grew favorably at the temperature of $23{\sim}28^{\circ}C$ on MYG medium with pH 7.0. The fruiting-body of I. japonica was induced below $20^{\circ}C$ in MYG liquid medium (Malt yeast glucose) under fluorescent light. In MYG basal medium mixed with pupal powder of silkworms, the fresh weight of fruiting-bodies was increased with increasing concentration of pupal powder. The highest yield of fruiting bodies was obtained in carbon-rich medium supplemented with pupal powder of silkworm. Also, fruiting-bodies of I. japonica were produced massively on the silkworm pupa placed on the stainless tray in the shortest time. The structure and shape of fruiting-bodies were coral-like, many-branched types with numerous conidiospores.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.110-116
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• 2013

This study was carried out to establish the simple mass-screening methods for resistant tomato to Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Root dip inoculation method has been used in many studies on the resistance of tomato to disease. On the other hand, in mass-screening for resistant tomato to Fusarium wilt, the inoculation method is time-consuming and laborious procedure. Disease development of two FOL isolates on two cultivars of tomato according to inoculation method including root dip, tip and scalpel methods were investigated. In compatible interaction, tomato seedlings of each cultivar inoculated by tip method showed the lower and more variable disease severities than by root dip method. Whereas the seedlings by scalpel method represented clear resistant and susceptible responses to Fusarium wilt as root dip method. The resistance degree of each cultivar inoculated with FOL isolates by scalpel method was hardly affected by the tested incubation temperature and inoculum concentration. On the basis of the results, we suggest scalpel inoculation method as an efficient mass-screening method for resistant of tomato cultivars to Fusarium wilt. Roots of tomato seedlings at two-leaf stage grown in plastic cell tray were injured with scalpel and then spore suspension (more than $1{\times}10^7\;conidia{\cdot}mL^{-1}$) of FOL was poured directly on the roots. The infected plants were cultivated in a growth room at $25-30^{\circ}C$ for 4 weeks with 12-hours light a day.