• The Journal of Korean Academy of Prosthodontics
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• v.56 no.3
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• pp.243-249
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• 2018

Excessive tooth wear results in unacceptable damage to the occlusal surface and can cause pulpitis, occlusal disharmony, dysfunction, and unesthetic result. Patients with severe attrition have to be classified as several types relative to the vertical dimension of occlusion (VDO) and the interocclusal distance for the prosthetic space. The patient in this case was a 80 - year - old woman who lost support of posterior occlusion and collapsed of the occlusal plane due to confrontation of the opposing teeth, accompanied by an increase in the number of remaining bristles, resulting in a loss of intermaxillary space for prosthesis. In this case, treatment with increased vertical dimension may have stability if the increase in vertical occlusal height is minimized within the required range, and a stable occlusal contact is provided after an increased vertical occlusal height stabilization period. After the new VDO had been confirmed under interim fixed restorations, definitive fixed restorations were produced. Through these treatment processes, we obtain satisfactory results that are functional and aesthetically pleasing.

• Journal of the Korea Fashion and Costume Design Association
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• v.16 no.4
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• pp.217-228
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• 2014

The purpose of this study is to grasp inconveniences and improvements by examining wearing condition and satisfaction of protective clothing targeting 114 Korean farmers and to suggest basic data for enhancement of pattern and wearing satisfaction of protective clothing by understanding problems of pesticide-proof clothing through comparative analysis on the size of its commercial products. Most of male subjects were in charge of spraying pesticide, whereas female were most likely to play an assistant role to hold the hose of pesticide applicator. Both of female and male subjects were very aware of the harmful effect of pesticide on human body and tried to take off the clothes immediately after spraying it to reduce possible damage caused by pesticide. As a result of examining wearing condition, the farmers avoided wearing protective clothing because that it feels hot, stuffy, and uncomfortable to move. This hesitant response of wearing the clothing was not shown significantly in case of female subjects who play an assistant role for spraying. Although the farmers wore protective equipments such as mask or gloves in a proper way as compared to protective clothing, they seemed to choose alternative way rather than best way to block pesticide completely. The satisfaction regarding to the fitting of protective clothing which the subjects showed low in all items of upper-lower clothes except waistline. It is necessary to improve the functionality such as relief from heat stress and convenience for movement rather than design or economic in protective clothing development. As a result of comparing the size of five kinds of commercial protective clothing, the farmers got confused to choose the product since designation method of size across companies showed a significant difference in an identical clothing size. In addition, the sizing system developed on a basis of a well-built man has become a hindering factor in wearing satisfaction of female farmers.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.84-92
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• 2020

Most facilities in chemical plants operate in environments that are outside the range of temperature and pressure that can be encountered on a daily basis, and are vulnerable to aging due to these stresses and environmental conditions. The facilities exposed to these conditions are not only likely to fail due to cumulative damage, but also lead to accidents if maintenance and replacement are not performed.Recommendation guidelines called risk-based inspection are widely used around the world-wide. However, limits exist for facilities that have already elapsed for a certain. As a result of the survey on the aging of Ulsan industrial complex in Korea, which carries out proper inspection, many of the facilities have been used for 20 years. Also, most of the facilities where the accident occurred have been in operation for more than 20 years. Therefore, this study suggested criteria for classifying devices that have exceeded a certain period of use as obsolete facilities. In addition, quantitative risk assessment was conducted. The safety investment method using the cost-benefit analysis method was proposed in order to calculate the loss cost and reduce the risk by expressing the risks of the corresponding aged facility as an Economic index. By utilizing the method of cost-benefit analysis of old facilities using the quantitative risk assessment presented in this study, it can be expected to improve the performance and life of old facilities, improve production efficiency and reliability of the system of facilities, change the recognition of safety management costs, increase employee stability, and reduce loss costs.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.170-176
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• 2016

Superintendents have used a silicate fertilizer to improve a resistance of turfgrass against several diseases, drought damage and wear stress. This study was conducted to evaluate the effect of liquid fertilizer containing silicate (LFSi) on changes of turfgrass quality and growth by investigating visual quality, chlorophyll content-chlorophyll a, chlorophyll b, and total chlorophyll, root length, shoot length, dry weight of clipping, and nutrient content in leaves tissue. Treatments were designed as follows; control fertilizer (CF), SiF-1 (CF + $1ml\;m^{-2}$ LFSi), SiF-2 (CF + $2ml\;m^{-2}$ LFSi), and SiF-3 (CF + $4ml\;m^{-2}$ LFSi). As compared with CF, soil chemical properties, visual turfgrass quality, chlorophyll content, and dry weight of clipping of LFSi treatments were not significantly. Contrastingly, shoot density, root length, and the content of nitrogen or potassium were increased by application of LFSi. The content of Si in the tissue was positively correlated with potassium content or shoot length, and similarly shoot density positively with chlorophyll content or visual quality, respectively. These results suggested that the application of LFSi improved the turfgrass quality by increasing shoot density or K content in leaf tissue of creeping bentgrass.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.4
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• pp.339-345
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• 2008

The heat exchanger tube in nuclear power plants is mainly fabricated from nonferromagnetic material such as a copper, titanium, and inconel alloy, but the moisture separator & reheater tube in the turbine system is fabricated from ferromagnetic material such as a carbon steel or ferrite stainless steel which has a good mechanical properties in harsh environments of high pressure and temperature. Especially, the moisture separator & reheater tubes, which use steam as a heat transfer media, typically employ a tubing with integral fins to furnish higher heat transfer rates. The ferromagnetic tube typically shows superior properties in high pressure and temperature environments than a nonferromagnetic material, but can make a trouble during the normal operation of power plants because the ferrous tube has service-induced damage forms including a steam cutting, erosion, mechanical wear, stress corrosion cracking, etc. Therefore, nondestructive examination is periodically performed to evaluate the tube integrity. Now, the remote field testing(RFT) technique is one of the solution for examination of ferromagnetic tube because the conventional eddy current technique typically can not be applied to ferromagnetic tube such as a ferrite stainless steel due to the high electrical permeability of ferrous tube. In this study, we have designed RFT probes, calibration standards, artificial flaw specimen, and probe pusher-puller necessary for field application, and have successfully carry out RFT examination of the moisture separator & reheater tube of nuclear power plants.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.237-246
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• 2015

Purpose: The present study was conducted to reveal the correlation of structural denaturation and decrease of enzyme activity when the antioxidative enzymes, superoxide dismutase (SOD) and catalase (CAT) were repeatedly exposed to UV-B, and further investigate whether the denaturation and inactivation of those enzymes can be effectively blocked by using UV-inhibitory RGP lens. Methods: Each enzyme solution was prepared from the standardized SOD and CAT, and repeatedly exposed to UV-B of 312 nm for 30 minutes, 1 hour and 2 hours a day over 1, 2, 3, 4 and 5 days. Structural denaturation of SOD and CAT induced by repeat UV-B irradiation was confirmed by the electrophoretic analysis, and their enzyme activity was determined by the colorimetric assay using the proper assay kit. At that time, the change in structure and activity of the antioxidant enzymes directly exposed to UV-B was compared to the case that UV-B was blocked by UV-inhibitory RGP lens. Results: SOD exposed repeatedly to UV-B showed the polymerization pattern in the electrophoretic analysis when it repeatedly exposed for 30 min a day, however, the change of its activity was less than 10%. On the other hand, CAT repeatedly exposed to UV-B reduced size and density of the electrophoretic band which indicated a structure denaturation, and its activity was significantly decreased. In the case that the repeat exposure time was longer, CAT activity was completely lost even though some enzyme band occurred in the electrphoretic analysis. In addition, the degeneration of CAT due to UV-B irradiation was inhibited to some extent by using RGP lens with a UV-B blocking of 63.7%, however, it was not completely inhibited. Conclusions: From these results, it was revealed that the structural denaturation of antioxidative enzymes was not perfectly correlated with the reduction in enzyme activity according to the type of enzyme. It is recommended to minimize the exposure time to UV when wearing contact lens, or wear the contact lenses having UV blocking rate of the FDA Class I blocker or the sunglasses having equivalent UV-blocking rate for reducing the damage of antioxidative enzymes induced by UV.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.137-146
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• 2007

Traffic causes more and more stress and injury to grasses on golf course green in Korea due to the increased playing. This study compared the effect of fertilizer component (Nitrate, Phosphate, Potassium) on turfgrass growth and quality golf course green under traffic stress during early winter. Experiment was conducted by using different fertilizer components for 2 months(Oct. 1 to Nov. 30, 2005). Turfgrass leaf color, leaf texture, density and traffic tolerance were evaluated visually, and the root length(cm) and tiller density(tiller/$cm^2$) were measured. Creeping bentgrass(Agrostis palustris cv. 'Seaside II') fromthe nursery of Incheon Grand Golf Club was used. Results of this study are as followings: 1). Turfgrass color was the best in A6(20-15-10) and A5(15-15-10) treatments in the N study. Leaf texture was not different among treatments. Turf quality and traffic tolerance were the highest In A5 and A6. Root length was the longest(15.8cm) in A6 (20-15-10). Root length increased with nitrogen levels. 2). Turf color of A9(5-7.5-5) and A10(15-22.5-15) was darkest in the comparison of P study. Leaf texture was the best in A4(10-15-10) and A9. Turf quality was the best in A10. A7(10-0-10). 3). In general, to recover turfgrass damage on the putting greens during low temperature period, fertilizer amount need to be increased; and nitrogen is better than phosphate and potassium for that purpose.

• Korean Journal of Heritage: History & Science
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• v.44 no.1
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• pp.52-71
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• 2011

This study was initiated with the intent to consider the features of Gugokwonlim and to compare Gabsagugok(甲寺九曲) to Yongsangugok(龍山九曲) against the backdrop of Mt. Gyeryong by revealing their nature and confirming the names and exact locations. A literature review, interviews with local people and field studies confirmed that Gabsagugok and Yongsangugok are each composed of 9 seasonal features. The former is made up of Yongyuso(龍遊沼) - Iilcheon(二一川) - Baengnyonggang(白龍岡) - Dalmuntaek(達門澤) - Geumgyeam(金鷄?) - Myeongwoldam(明月潭) - Gyemyeongam(鷄鳴巖) - Yongmunpok(龍門瀑) - Sujeongbong(水晶峰) while the latter is made up of Simyongmun(尋龍門) - Eunnyongdam(隱龍潭) - Waryonggang(臥龍剛) - Yuryongdae(遊龍臺) - Hwangnyongam(黃龍岩) - Hyeollyongso(見龍沼) - Ullyongtaek(雲龍澤) - Biryongchu(飛龍湫) - Sillyongyeon(神龍淵). Both Gabsagugok and Yongsangugok are part of Gugokwonlim built in the valleys of Mt. Gyeryong in the late Joseon Dynasty by Byeoksu Yun Deok-yeong (1927) and Chwieum Gwon Jun-myeon (1932), respectively, with a 5 year difference. Gabsagugok was supposedly designed to reflect an individual taste for the arts and to admire principles of Juyeok (ch. Zhouyi) and the beauty of nature. On the contrary, Yongsangugok appears to be the builder's expression of his longing for independence day, likened to the life of a dragon after receiving the sad news of Japan's annexation of Korea. Such differences show that these two builders had very different intentions from one another. The letters of Gabsagugok have a semi cursive style and were deeply engraved on the rock in a square shape. Consequently they have not been worn away except for those in Yongyuso, the first Gok. In contrast, the letters in Yongsangugok have an antiquated, cursive-Yija style but because they were engraved relatively lightly, serious wear and damage occurred. In terms of location, Gabsagugok was built around Ganseongjang adjacent to the 5th Gok while Yongsangugok was set up around the 5th Gok, Hwangnyongam. Meanwhile, the important motif which forms the background of Gabsagugok seemingly highlights the geographic identity of Mt. Gyeryong using the dragon and the chicken as themes. It also appears to symbolize the principles of Juyeok focusing on Kan of the Eight Trigrams for divination; this requires an in-depth study for confirmation. The main motif and theme of Yongsangugok is the dragon. It infuses the builder's intentions in Sangsinri Valley by communicating with nature through a story of a dragon's life from birth to ascension. It is assumed that he tried to use this story to express his hope for restoring the national spirit and reconstructing the country.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.104-114
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• 2024

Sheet Music of the National Anthem of Korea with Lyrics in Korean, Chinese, and English is a four-sided sheet of paper folded in half. It was first introduced to Korea on November 12, 1945, by Kim Ku, the president of the Provisional Government. The sheet music was published in three languages and is a valuable document for researching the evolution of the anthem and its history. Although it was published in large quantities at the time, it is currently known as the only in Korea and has been designated and managed as a national registered heritage. The sheet music was not significantly damaged, but discoloration and physical damage suggested raised the need for conservation treatment. A pre-treatment examination of the conservation condition revealed that the artifact was received on archival film and had been folded in half for many years, leaving it vulnerable to tears at the top and bottom of the folds and partial wear and tear at the edges. In addition, the pigments used on both sides of the sheet had discolored and transferred to the opposite side. Portable X-ray fluorescence (XRF) analysis was conducted to investigate the pigments used in the sheet music cover, specifically focusing on red, black, and light blue pigments. Titanium (Ti) was detected in the light blue pigment, characterized by a powdery coloring layer. The remaining colors in the printed form were difficult to sample and could not be analyzed further. The light blue sample underwent additional analysis using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and Raman spectroscopy. Cross-validation of the results with the artifact's historical context suggested that the bright blue color observed in the 1945 sheet music is likely due to the use of anatase white pigment, rather than rutile. Furthermore, the bright blue pigment is believed to be a blend of phthalocyanine blue, a synthetic pigment introduced in 1936. Fiber analysis revealed longitudinal striations in the hemp fibers and twists in the cotton fibers, suggesting that the paper was made from a mixture of cotton and hemp fibers. Based on the findings of the condition survey, the conservation treatment for the artifact focused on minimizing moisture to avoid stressing the paper and reinforcing the physically vulnerable areas. The reinforcement paper was dyed to match the base of the artifacts, pre-coated repair paper was used for conservation, and appropriate folders and boxes were made for storage after treatment. This study is expected to serve as an important foundational resource on the materials used in modern and contemporary records.