• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.537-545
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• 1995

Quality changes of lettuce were studied during storage to investigate the efficiency, cooling properties and the washing and storage effects of immersion-type hydrocooling. As a result of plotting the nondimensionalized lettuce temperature versus cooling time, its cooling rate coefficient was shown to be $-0.365\;min^{-1}{\sim}-0.255\;min^{-1}\;(R^2=0.99{\sim}0.88)$. Rate of weight loss was not significantly (p>0.05) different between lettuces with various treatment conditions during storage at $5^{\circ}C$. However, during storage at $15^{\circ}C$, weight loss of hydrocooled lettuce was lower than that of non-treated lettuce after from 10 to 15 days. Especially, The lettuce packed with PE was more effective than that packed with try in terms of packing condition after hydrocooling. Lettuce pretreated with sterilizing agent, packed with PE vinyl film, removed residual water after hydrocooling had lower decaying rate than any other lettuces. Changes of L and b values in hydrocooled lettuce were slower than those of non-treated one. During changes of chlorophyll content, the initial value, $115.7{\sim}147.3\;mg%$ was decreased to $50{\sim}60%$ after 25 days of storage at $5^{\circ}C$ and within 15 days of storage at $15^{\circ}C$. It could be presumed that the addition of sterilizing agent reduced the initial level of overall total and coliform count and its growth rate during storage. The respiration rate of hydrocooled lettuce at $5^{\circ}C$ was $23.95\;mg{\cdot}CO_2/kg\;hr$, which is 10% of those of non-treated lettuce.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.303-317
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• 1994

This study was designed to measure the changes in the titer of tooth root antibodies accompanying root resorption associated with orthodontic tooth movement in dogs to explore a role of the specific immune response in root resorption during orthodontic tooth movement. Five adult mongrel dogs, 2 years of age, were used in the study. Six lower incisors were extracted as sources of homologous antigen in the dogs. Tooth root antigen preparations were made from a 6M Guanidine-HCl-10% EDTA(pH5.0) extract of these root dentins. Root resorption was elicited by intrusion of six maxillary incisors with 200-250gm intrusive force. In 9th week, resorbing six maxillary anterior teeth were extracted. Serum samples were taken from each dog prior to intrusion and weekly for 11 consecutive weeks. Serum autoantibody titers were determined with an enzyme-linked immunosorbent assay. As controls for antibody specificity, sera which were previously incubated with tooth root antigen as well as sera to an unrelated bacterial antigen (Porphyromonas gingivalis 33277) for 3 hours at 25 were measured in all runs. Root resorption was monitored monthly using occlusal radiographs. And then root resorption patterns were observed with a zoom stereo microscope (Model SZH-121, Olympus optical Co. Ltd.). Incisors did not show clear radiographic evidence of significant and progressive root resorption, but periodontal ligament space had widened. But root resorption was observed on the apical regions of the maxillary incisors with a zoom stereo microscope. Teeth showed the shallow depression generally accompanying deep resorption. These demonstrate a slight tendency for an immediate decrease followed by rebound to levels above the pre-treatment baseline. A peak titer of autoantibody to dentin antigen occurred on day 28, then steadily decreased during the 9th week period as the roots resorbed and then rapidly spiked in animals when the resorbing teeth were extracted. When sera is incubated with tooth root antigen, serum activity in the ELISA was almost absent. This is because serum activity in the ELISA could be removed by absorption of the serum with dog dentin antigen. Serum ELISA activity to the unrelated bacterial antigen remained essentially unchanged in all animals throughout the experimental period. When the time course of changes in autoantibody to homologous tooth root antigen prepatration and unrelated bacterial antigen was compared, no significant differences were found(${\alpha}=0.05$). In general, the overall pattern of changes in autoantibody was similar to the two antigens. These findings suggest the possibility that these immunologic changes precede a significant development of root resorption lesions rather than merely reflecting their presence. Therefore, this suggests that the changes of antibody levels may have some predictive value for root resorption.

• Sijohaknonchong
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• v.42
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• pp.29-68
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• 2015

This article focused on the development and current status of Sijo-chang, the Korean classical vocal genre, which is the text as a fixed form of Korean classical poems. Historically, Sijo-chang has originally emerged from Hyangga鄕歌 during Silla period (BC. 57- AD. 935). However, the current Sijo-chang has been developed from the latter of Joseon朝鮮 period(AD. 1392-1910) in 1800s. Since 1800s, Sijo-chang derived from the Gyeong-je Pyeong sijo京制 平時調, which was established in Seoul, was able to accelerate its musical types and regional characteristics among the Korean peninsula. By setting a clear division of two time periods between 1800s and those periods since 1900s to today, this article mainly explains how Sijo-chang has been developed historically. First of all, in order to appraise the musical styles and characteristics of Sijo-chang in 1800s, comparing the current musical types of Sijo-chang and those printed old score books which has its historical musical characteristics during 1800s is necessary. Secondly, this paper concentrated on the transmitted lineages of representative vocalists among the regional-based Sijo-chang from 1900s to today. During those periods, the Sijo-chang has formed its particular regional-based musical characteristics among the Korean peninsula such as Yeong-je嶺制 of Gyeongsang province慶尙道, Naepo-je內浦制 of Chungcheong province忠淸道 and Wan-je完制 of Cheolla province全羅道. Although it was not a type of regional-based Sijo-chang, as a creation with reference based on certain regional types of Sijo-chang in 1960s, this paper introduced the inheritance process of Seogam-je石菴制 which was made by Jung Gyeong-tae鄭坰兌 named Seogam石菴 as his pen name. Since Seogam-je has been singing as the most influential musical types of Sijo-chang through the mainly southern region of Korean peninsula and even in Seoul, it was highly significant to research it. In addition, this paper elaborately highlighted the developments of various Sijo-chang based on its historical performances, studies, and the composed pieces from the early 1900s or the mid-1900s. In conclusion, in order to set a vigorous development of Sijo-chang, this paper raised several concerns among the future of Sijo-Chang and the significance of its traditional value.

• The Journal of Korean Society for Radiation Therapy
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• v.16 no.2
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• pp.69-79
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• 2004

In the process of photon treatments, linear accelerators with energies higher than 10 MV produce neutrons through the (${\gamma}$, n) interactions with the composite materials of the linac head md these materials further produce the induced radiations. We investigate the possible risks from these induced radiations especially in the wedge filters to the radiation workers. Wedge filters are used to modify the isodose profiles in the radiation treatment using the linear accelerator and always be handled by the radiation workers. For the background radiation, we measured the radiation in both the waiting room and the outside of the building for two hospitals, S and H. The results of S hospital were $0.11\;{\mu}Sv/hr$ and $0.10\;{\mu}Sv/hr$ for waiting room and outside respectively, and in the case of H hospital, they were $0.12\;{\mu}Sv/hr$ and $0.11\;{\mu}Sv/hr$. Using a survey meter, we measured the radiation from wedge filters inserted in 10 MV and 15 MV Siemens linear accelerators. The time series measurements were done in ${\sim}1$ minutes after exposure of 5 Gy of monitor units for the field size of $25{\times}25cm^2$. The starting value of 10 MV machine was about $3.26\;{\mu}Sv/hr$, which was three times higher than that of 10 MV. The measured radiation was from $^{28}Al$ and $^{53}Fe$ with a half life of 3.5 min. If the treatment patients are $20{\sim}50$ per day and the number of process of wedge filter change per patient is one or two, the annual dose equivalent is $0.08{\sim}0.4\;mSv$ for 10 MV, and $0.27{\sim}1.36\;mSv$ for 15 MV, which are in the range of dose equivalent limits of radiation workers.

• (The) Research of the performance art and culture
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• no.36
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• pp.693-724
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• 2018

This article was started to find a way for creating a performance out of Gut. In order to find such way, the first thing that had to be done was to organize the Gut performances that had been made until now. It was to organize the existing study on the performances and to seek a different way from it, believing that the virtue of a performance is to 'create diversity'. However, it was not easy to organize the Gut performances, which became full-scale in the 1980s, because they were never organized before. Therefore, based on my direct and indirect experience, I have organized the most important performances in chronological order. Most importantly, as the planners of the performances (can sometimes be a group or an organization instead of an individual) are the ones who make the show possible, I have noted on them with keen interest. The National Folk Art Performance Contests in Korea, Theater 'Space Sarang', The Association of Gut, Theater 'Madangsesil', Seoul Nori Madang, and National Gugak center were the center space and planning body of the Gut performances. Recording the history of Gut is a worthwhile work of its own. However, it is a substantial amount of task to be done with individual effort, and it has to be progressed as a public project in order to promote and spread its value. Therefore, this article raises the need for it. Meanwhile, as stated earlier, this article has recorded the history of Gut performances as a precondition to finding a way to create a performance out of Gut. From the experimental organization of the Gut performances history, I could find out that most of the performances had the people who did Gut as the main body and the method of the Gut performance did not significantly deviate from just reenacting the original Gut at the time of when it was performed. Therefore, I have introduced Shinmyeong, the Nori-Pae (troupe), and TheGwangdae, the Korean Traditional Performance troupe, who create Madangguk from various Gut materials. By refining the wholly complicated performance elements of the Gut, it could escape from the 'reenacting' performance to becoming a material or a metaphor for a whole new performance.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.202-209
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• 2018

This study was conducted to compare annual productivity of whole crop rice and winter crops in paddy field of southern region in Korean peninsular. Whole crop rice (WCR) varieties used in this experiment were Suwon 605, Yeongwoo, and Mogwoo bred at the National Institute of Crop Science (NICS), and Rye (Gogwoo), Italian ryegrass(IRG, Greenfarm) and Triticale (Choseong) were used as winter crops. Each crop was cultivated using the standard cultivation method and harvesting of whole rice was carried out about 30 days after heading date. The dry matter (DM) content was the lowest in Italian ryegrass (p<0.05), and the highest value was 29.4% in triticale. The dry matter yield of rye was the highest (p<0.05), and there was no significant difference between Italian ryegrass and triticale (p>0.05). There was no difference in forage quality among seeding time of each species, but there was a difference among the species (p<0.05). In particular, rye showed lower CP, IVDMD, TDN and RFV values than other species. The average dry matter production of whole crop rice was 18,484 kg/ha, but there was no significant difference among the cultivars (p>0.05). Crude protein (CP) content was significantly lower in Mogwoo than other and TDN and RFV values were the highest in Mogwoo. In the annual productivity evaluation, combination of rye-Suwon 605 showed the highest DM yield at 26,515kg/ha. Based on the above results, it was concluded that the combination of Suwon 605-rye (Gogwoo) was the most effective cropping system for annual forage production using whole crop rice and winter crop in the southern region of Korean peninsular.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.23-33
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• 2021

In Korea, many reservoirs have been built for the purpose of solving the food shortage problem and supplying agricultural water. However, the current 75.6% of the reservoirs are in serious aged as more than 50 years have passed since the year of construction. In the case of such an aging reservoir, the stability due to scour and erosion inside the reservoir is very reduced, and if concentrated rainfall due to recent abnormal weather occurs, the aging reservoir may collapse, leading to a lot of damage to property and human life. Accordingly, each agency that manages aging reservoirs uses Ordinary Portland Cement (OPC) as an injection material and applies the grouting method. However, in the case of OPC, it may deteriorate over time and water leakage may occur again. And there are environmental problems such as consumption of natural resources and generation of greenhouse gases. So, there is a need to develop new materials and methods that can replace the OPC. In this study, an laboratory test and analysis were performed on the grout material developed to induce a curing reaction similar to that of OPC by recycling power plant byproduct. In addition, test in the field such as electric resistivity survey, Standard Penetration Test (SPT), and field permeability test were performed to analyzed to reinforcement effect and determine the possibility of using instead of OPC. As a results of the test, in the case of recycled power plant byproduct, the compressive strength was 2.9 to 3.2 times and the deformation modulus was 2.3 to 3.3 times higher, indicating that it is excellent in strength and can be used instead of OPC. And it was analyzed that the N value of the reservoir was increased by 1~2, and the coefficient of permeability (k) decreased to the level of 8.9~42.5%. showing sufficient reinforcing effect in terms of order.

• (The)Study of the Eastern Classic
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• no.49
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• pp.161-185
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• 2012

This thesis reorganized the life of Mrs. Yun who was a noble woman in the middle of the Joseon period with main material of Seopo, Kim, Man Joong(1637-1692)'s "Seonbijungkyungbuinhaengjang(先?貞敬夫人行狀)" and considered yeosa(女師)'s image of noble woman embodied by her son. Although women who were remarkable in premodern period nurtured their son well and they became excellent, it's easy that the life of their mother can be hidden by sons' shadow. Luckily, materials of Mrs. Yun were kept by her descendants, so people could analogize how she could endure difficulties and how she educate her children. In a word, the life of Mrs. Yun can be yeosa(女師)'s life. She was born as a only daughter of the best ancestry in the period and grown to be a considerable woman with strong will and discipline under the strict training of her grandmother, Junghye Ongju. And then, she married Gwangsan Kimmun, the best literature house of Joseon period, but her husband, Kim, Ik Kyum was died by unexampled difficulty, Byungjahoran. During the tribulation, Mrs. Yun was in charge of not only parents supporting but also two sons' education excellently. She educated not only her children but also grandchildren and nephews around her, so she had extraordinary passion and sincerity for the education. As the result, she enjoyed a glory that two sons and grandchildren became on daejehak. Mrs. Yun was living with thrift and saving continuously regardless of her circumstances. When her granddaughter became inkyungwanghoo who is a wife of sookjong, she didn't kick her common habit and trained strictly the mind of family members who could be easily in disorder. In spite of the richness, he obeyed manners and showed thrift and saving continuously and thoroughly. When there was a crisis in her family, the first son, Kim, Man Ki was died and the second son, Kim, Man Joong and grandson went into exile during the continuous political upheaval. But, she supported her house, obeyed the rules and promised the future. At that time, she continuously encouraged grandchildren and the eldest grandsons of the head family to study without any stop for themselves in spite of the difficulties. Mrs. Yun pursued truly valuable life. She considered that the life which didn't get praised by other people wasn't valid although he or she lived a pleasant life in luck and richness. Mrs. Yun was a true teacher yeosa (女師) who placed a true value on the life enduring hardship and poorness without fear and becoming an example of other people.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.1
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• pp.41-50
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• 2022

In this paper, a method to directly calculate the major elements of skin color such as melanin and hemoglobin from the RGB signal of the camera is proposed. The main elements of skin color typically measure spectral reflectance using specific equipment, and reconfigure the values at some wavelengths of the measured light. The values calculated by this method include such things as melanin index and erythema index, and require special equipment such as a spectral reflectance measuring device or a multi-spectral camera. It is difficult to find a direct calculation method for such component elements from a general digital camera, and a method of indirectly calculating the concentration of melanin and hemoglobin using independent component analysis has been proposed. This method targets a region of a certain RGB image, extracts characteristic vectors of melanin and hemoglobin, and calculates the concentration in a manner similar to that of Principal Component Analysis. The disadvantage of this method is that it is difficult to directly calculate the pixel unit because a group of pixels in a certain area is used as an input, and since the extracted feature vector is implemented by an optimization method, it tends to be calculated with a different value each time it is executed. The final calculation is determined in the form of an image representing the components of melanin and hemoglobin by converting it back to the RGB coordinate system without using the feature vector itself. In order to improve the disadvantages of this method, the proposed method is to calculate the component values of melanin and hemoglobin in a feature space rather than an RGB coordinate system using a feature vector, and calculate the spectral reflectance corresponding to the skin color using a general digital camera. Methods and methods of calculating detailed components constituting skin pigments such as melanin, oxidized hemoglobin, deoxidized hemoglobin, and carotenoid using spectral reflectance. The proposed method does not require special equipment such as a spectral reflectance measuring device or a multi-spectral camera, and unlike the existing method, direct calculation of the pixel unit is possible, and the same characteristics can be obtained even in repeated execution. The standard diviation of density for melanin and hemoglobin of proposed method was 15% compared to conventional and therefore gives 6 times stable.