• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.2
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• pp.162-168
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• 2006

Purpose: Microbial colonization of the intestine begins just after birth and development of the normal flora is a gradual process. The first bacteria colonizing the intestine in newborns are Staphylococcus, Enterobacteriaceae and Streptococcus. For several days after birth, the number of Bifidobacterium spp. increase. The aim of this study was to investigate the changes of microflora for seven days postnatally in neonatal stool. Methods: Fifteen neonates (breast : formula : mixed feeding 1 : 8 : 6, vaginal delivery : cesarean section 3 : 12) who were born at the Kangdong Sacred Heart Hospital, Hallym University were enrolled. First meconium and stools of postnatal 1-, 3-, and 7-day were innoculated. Blood agar plates for total aerobes, trypton bile X-glucuronide agar for E. coli, phenylethyl alcohol agar for gram positive anaerobes, MRS agar for Lactobacillus spp., bifidobacterium selective agar for Bifidobacterium spp. and cefoxitin-cycloserine-fructose agar for Clostridium difficile were used in the general incubator ($CO_2$ free incubator), $CO_2$ incubator or the anaerobic chamber for 48 or 72 hours at $37^{\circ}C$ and then colony forming units were counted. Results: No microflora was identified in the first meconium. Total aerobes, E. coli, and gram positive anaerobes were significantly increased with advancing postnatal days. In only one baby, Lactobacillus acidophilus was detected $2{\times}10^5CFU/g$ in the seven-day stool. Bifidobacterium spp. was detected in two babies. Clostridium difficile was not detected during the seven days. There were no significant differences in the bowel flora depending on the delivery pattern and feeding method. Conclusion: This study shows many changes in the intestinal normal flora in neonatal stool during seven days postnatally. If these findings are confirmed with larger studies, the data may be preliminary findings to support use of probiotics in neonates.

• Progress in Medical Physics
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• v.23 no.4
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• pp.219-228
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• 2012

The tangential breast intensity modulated radiotherapy (T-B IMRT) technique, which uses the same tangential fields as conventional 3-dimensional conformal radiotherapy (3D-CRT) plans with physical wedges, was analyzed in terms of the calculated dose distribution feature and dosimetric accuracy of beam delivery during treatment. T-B IMRT plans were prepared for 15 patients with breast cancer who were already treated with conventional 3D-CRT. The homogeneity of the dose distribution to the target volume was improved, and the dose delivered to the normal tissues and critical organs was reduced compared with that in 3D-CRT plans. Quality assurance (QA) plans with the appropriate phantoms were used to analyze the dosimetric accuracy of T-B IMRT. An ionization chamber placed at the hole of an acrylic cylindrical phantom was used for the point dose measurement, and the mean error from the calculated dose was $0.7{\pm}1.4%$. The accuracy of the dose distribution was verified with a 2D diode detector array, and the mean pass rate calculated from the gamma evaluation was $97.3{\pm}2.9%$. We confirmed the advantages of a T-B IMRT in the dose distribution and verified the dosimetric accuracy from the QA performance which should still be regarded as an important process even in the simple technique as T-B IMRT in order to maintain a good quality.

• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.66-72
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• 2009

The detection methods are required to monitor and diagnose the abnormality on the insulation condition inside a gas-insulated switchgear (GIS). Due to a good sensitivity to the products decomposed by partial discharges (PDs) in $SF_6$ gas, the development of a SWNT gas sensor is actively in progress. However, a few numerical studies on the diffusion mechanism of the $SF_6$ decomposition products by PD have been reported. In this study, we modeled $SF_6$ decomposition process in a chamber by calculating temperature, pressure and concentration of the decomposition products by using a commercial CFD program in conjunction with experimental data. It was assumed that the mass production rate and the generation temperature of the decomposition products were $5.04{\times}10^{-10}$ [g/s] and over 773 K respectively. To calculate the concentration equation, the Schmidt number was specified to get the diffusion coefficient functioned by viscosity and density of $SF_6$ gas instead rather than setting it directly. The results showed that the drive potential is governed mainly by the gradient of the decomposition concentration. A lower concentration of the decomposition products was observed as the sensors were placed more away from the discharge region. Also, the concentration increased by increasing the discharge time. By installing multiple sensors the location of PD is expected to be identified by monitoring the response time of the sensors, and the information should be very useful for the diagnosis and maintenance of GIS.

• Korean Journal of Heritage: History & Science
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• v.50 no.1
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• pp.42-57
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• 2017

The Joseon Dynasty (1392~1910) had a long tradition of making official seals to commemorate the granting of official royal titles, including posthumous honorary titles, to its kings, queens, crown princes and queen dowagers. These royal seals were typically gold-plated or made of jade. After the death of its holder, each seal would be stored in the royal seal depository in the Royal Ancestral Shrine. Extensive efforts were made to restore the traditions and culture of the royal family of Joseon during the reign of King Sukjong (r. 1674~1720). In 1705, discussions were held about the royal ceremonial objects, including the royal seals, stored in the Royal Ancestral Shrine, resulting in the reproduction of a set of accessories related with the storage of royal seals and ten golden royal seals which had been lost during wars or had yet to be made. With these reproductions, each shrine chamber of the Royal Ancestral Shrine would have had at least one seal. The details of the reproduction project were meticulously recorded in The Royal Protocol by the Directorate for the Restoration of Golden Royal Seals("金寶改造都監儀軌"). Given that the restoration project was the single event that led to the reproduction of all the golden royal seals, it is reasonable to conclude that the directorate had fulfilled a historically significant function. In this study, the main discussion is focused on the establishment of the directorate and the storage and management of the damaged royal seals. The discussion includes the manufacturing process of the golden seals, for which The Royal Protocol is compared with other similar documents in order to gain more detailed knowledge of the measurements of the turtle knob, the lost-wax casting technique, the gold plating with mercury amalgamation technique, and other ornamentation techniques. The discussion also covers the activities of the artisans who made the royal seals, based on a study of the royal protocols; the styles of the artifacts, based on an examination of the remaining examples; and the techniques used by the Directorate for the Restoration of Golden Royal Seals to produce the royal seals in 1705.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.31-40
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• 2019

In Korea, 51,013 thousand tons of livestock manure was generated in 2018. A total of 46,530 thousand tons, which is 91.2% of the total amount of livestock manure generated, was treated by composting(40,647 thousand tons) or liquid fertilization(5,884 thousand tons) method. At present, the policy of livestock manure treatment in Korea is to make livestock manure into organic fertilizer(compost, liquid fertilizer) and then to applicate it on agricultural land. And this policy is very effective in terms of livestock manure treatment and nutrient recycling. However, considering the steadily declining farmland area for decades, the use of livestock manure compost could be limited in the future. There is also concern that local nutrient overloading, nutrient management regulation, and restrictions on the number of livestock may become serious problem for livestock manure treatment. In addition, there are some opinions that nutrient derived from livestock manure may flow into tributaries of major dams. In recent years, there has been a suspicion that fine dust may be generated from livestock manure compost. In recent years, the use of livestock manure fertilizer has been rapidly increasing, there is a growing demand of the development of new technologies for livestock manure treatment. Especially, cow excretes a larger amount of manure than other livestock, so that the efficiency of development of new technology for cow manure treatment will be high. Therefore, in this study, the combustion characteristics of cow manure pellet were investigated in order to analyzed whether cow manure could be used as source of solid fuel. During the combustion test, the weight loss of the cow manure pellet began to increase when the temperature of the combustion chamber reached $300^{\circ}C$. The ratio of $H_2$, $CH_4$, CO in the pyrolysis gas produced in the pyrolysis process of cow manure pellet were 6.65~11.62%, 0.58~1.54 and 11.47~14.07%, respectively.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.134-149
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• 2013

The Sudang-ri Site in Geumsan is considered the historic site where Baekje dominated the inland traffic route to Gaya through Geumsan and Jinan in the 5th Century. This study identified the production techniques of iron by conducting an analysis of metallographical microstructure of the artifacts such as an iron sword and an iron sickle that were excavated in Sudang-ri Site, Geumsan, one of the regions ruled by Baekje, and tried to figure out the characteristics and the technical systems of Baekje's ironmaking around the 5th Century by comparing them with other iron artifacts produced around the same time. The analysis showed that various production techniques were applied to the artifacts excavated in Sudang-ri Site, Geumsan. Depending on the production techniques, they can be divided largely into three methods: the simple shape-forging method, the steel manufacture method after forging, and the steel manufacture & heat-treatment method after forging. The iron sickle from the stone chamber tomb No. 1, which was produced only through forging, is mostly composed of soft ferrite at both edges of the blade and at the rear making the use of the weapon impractical. From this fact, it is presumed that they were produced as burial objects or ceremonial accessories for the person buried. The iron axe from the outer stone coffin tomb No. 1 and the iron swords and sickle from the outer stone coffin tomb No. 12, which were produced through the steel manufacture method after forging such as carburizing, did not go through the heat treatment such as quenching, but applied different production processes to each part. Therefore, it is deemed that they were produced as daily tools for cultivation rather than burial objects or ceremonial accessories. The production techniques following the forging process - carburizing and heat treatment - can be found on the iron swords from the outer stone coffin tomb No. 5 and the outer stone coffin tomb No. 12. The sturdy structure of the blade part and the durable structure of the rear processed with heat are deemed to have been produced as weaponry and used by the person buried. Based on the analysis of the iron artifacts excavated from Sudang-ri Site in Geumsan, the characteristics of iron production techniques were investigated by comparing them with the artifacts from Yongwon-ri Site in Cheonan, Bongseon-ri Site in Seocheon, and Bujang-ri Site in Seosan that were made around the same time as the cluster of Baekje tombs examined by the metallographical microstructure analysis of this study. For the iron artifacts analyzed here, the changes in the techniques were investigated using the iron swords common in all of the tombs. In the case of the iron swords, it was identified the heat treatment technique called tempering was applied from the 4th Century.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.304-312
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• 2023

Plant breeding is a time-consuming process, mainly due to the limited annual generational advancement. A speed breeding system, using LED light sources, has been applied to accelerate generational progression in various crops. However, detailed protocols applicable to soybeans are still insufficient. In this study, we report the optimized protocols for a speed breeding system comprising 12 soybean varieties with various maturity ecotypes. We investigated the effects of two light qualities (RGB ratio), three levels of light intensity (PPFD), and two soil conditions on the flowering time and development of soybeans. Our results showed that an increase in the red wavelength of the light spectrum led to a delay in flowering time. Furthermore, as light intensity increased, flowering time, average internode length, and plant height decreased, while the number of nodes, branches, and pods increased. When compared to agronomic soil, horticultural soil resulted in an increase of more than 50% in the number of nodes, branches, and pods. Consequently, the optimal conditions were determined as follows: a 10-hour short-day photoperiod, an equal RGB ratio (1:1:1), light intensity exceeding 1,300 PPFD, and the use of horticultural soil. Under these conditions, the average flowering time was found to be 27.3±2.48 days, with an average seed yield of 7.9±2.67. Thus, the speed breeding systems reduced the flowering time by more than 40 days, compared to the average flowering time of Korean soybean resources (approximately 70 days). By using a controlled growth chamber that is unaffected by external environmental conditions, up to 6 generations can be achieved per year. The use of LED illumination and streamlined facilities further contributes to cost savings. This study highlights the substantial potential of integrating modern crop breeding techniques, such as digital breeding and genetic editing, with generational shortening systems to accelerate crop improvement.