• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1306-1313
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• 2011

A liquid fertilizer treated with slurry composting and biofiltration (SCB) process has been applied increasingly on agricultural field but the effects on the soil properties and crop production has not been throughly evaluated. This study was conducted to investigate the effect of the SCB application on soil chemical properties and the growth of radish and corn. SCB liquid fertilizer as a basal fertilization was treated with five levels based on $6kg\;10a^{-1}$ for radish and $10kg\;10a^{-1}$ for corn. The experimental design was the completely randomized block design with five levels and three replicates. Electrical conductivity (EC), $NO_3$-N, Exch. K and Exch. Na increased depending on the treatment levels of SCB. There were no changes in soil organic matter, Avail. $P_2O_5$, Exch. Ca and Exch. Mg. EC, $NO_3$-N and Exch. Na content decreased as precipitation increased. Especially, they decreased up to the initial condition before the treatment after the heavy rainy season in 2008. Although Exch. K decreased at the rainy season, they remained relatively higher content after the experiment on August, 2008. Fresh weight and the amount of N uptake of radish increased due to the levels of SCB, but corn did not present any significant increase. It is recommended that we need to decide the proper amount of SCB as well as the application method on the field to increase the productivity and decrease environmental stress. Additional experiments also need to clarify the effect of the trace element and heavy metal accumulations due to long term application of SCB.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.898-903
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• 2010

This study was carried out to estimate carbon emission using LCA (Life Cycle Assessment) and to establish LCI (Life Cycle Inventory) database of soybean production system. Based on collecting the data for operating LCI, it was shown that input of organic fertilizer was value of 3.10E+00 kg $kg^{-1}$ soybean and it of mineral fertilizer was 4.57E-01 kg $kg^{-1}$ soybean for soybean cultivation. It was the highest value among input for soybean production. And direct field emission was 1.48E-01 kg $kg^{-1}$ soybean during soybean cropping. The result of LCI analysis focussed on greenhouse gas (GHG) was showed that carbon footprint was 3.36E+00 kg $CO_2$-eq $kg^{-1}$ soybean. Especially $CO_2$ for 71% of the GHG emission. Also of the GHG emission $CH_4$, and $N_2O$ were estimated to be 18% and 11%, respectively. It might be due to emit from mainly fertilizer production (92%) and soybean cultivation (7%) for soybean production system. $N_2O$ was emitted from soybean cropping for 67% of the GHG emission. In $CO_2$-eq. value, $CO_2$ and $N_2O$ were 2.36E+00 kg $CO_2$-eq. $kg^{-1}$ soybean and 3.50E-01 kg $CO_2$-eq. $kg^{-1}$ soybean, respectively. With LCIA (Life Cycle Impact Assessment) for soybean production system, it was observed that the process of fertilizer production might be contributed to approximately 90% of GWP (global warming potential). Characterization value of GWP was 3.36E+00 kg $CO_2$-eq $kg^{-1}$.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.617-628
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• 2022

A ground support pattern should be designed by properly integrating various support materials in accordance with the rock mass grade when constructing a tunnel, and a technical decision must be made in this process by professionals with vast construction experiences. However, designing supports at the early stage of tunnel design, such as feasibility study or basic design, may be very challenging due to the short timeline, insufficient budget, and deficiency of field data. Meanwhile, the design of the support pattern can be performed more quickly and reliably by utilizing the machine learning technique and the accumulated design data with the rapid increase in tunnel construction in South Korea. Therefore, in this study, the design data and ground exploration data of 48 road tunnels in South Korea were inspected, and data about 19 items, including eight input items (rock type, resistivity, depth, tunnel length, safety index by tunnel length, safety index by rick index, tunnel type, tunnel area) and 11 output items (rock mass grade, two items for shotcrete, three items for rock bolt, three items for steel support, two items for concrete lining), were collected to automatically determine the rock mass class and the support pattern. Three machine learning models (S1, A1, A2) were developed using two machine learning algorithms (SVR, ANN) and organized data. As a result, the A2 model, which applied different loss functions according to the output data format, showed the best performance. This study confirms the potential of support pattern design using machine learning, and it is expected that it will be able to improve the design model by continuously using the model in the actual design, compensating for its shortcomings, and improving its usability.

• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• Publications of The Korean Astronomical Society
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• v.36 no.3
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• pp.65-78
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• 2021

Jagyeokru, an automatic striking water clock described in the Sejong Sillok (Veritable Records of King Sejong) is essentially composed of a water quantity control device and a time-signal device, with the former controlling the amount or the flow rate of water and the latter automatically informing the time based on the former. What connects these two parts is a signal generating device or a power transmission device called the 'Jujeon' system, which includes a copper rod on the float and ball-racked scheduled plates. The copper products excavated under Gongpyeong-dong in Seoul include a lot of broken plate pieces and cylinder-like devices. If some plate pieces are put together, a large square plate with circular holes located in a zigzag can be completed, and at the upper right of it is carved 'the first scheduled plate (一箭).' Cylinder-like devices generally 3.8 cm in diameter are able to release a ball, and have a ginkgo leaf-like screen fixed on the inner axis and a bird-shaped hook of which the leg fixes another axis and the beak attaches to the leaf side. The lateral view of this cylinder-like device appears like a trapezoid and mounts an iron ball. The function of releasing a ball agrees with the description of Borugak Pavilion, where Jagyeokru was installed, written by Kim Don (1385 ~ 1440). The other accounts of Borugak Pavilion's and Heumgyeonggak Pavilion's water clocks describe these copper plates and ball releasing devices as the 'Jujeon' system. According to the description of Borugak Pavilion, a square wooden column has copper plates on the left and right sides the same height as the column, and the left copper plate has 12 drilled holes to keep the time of a 12 double-hours. Meanwhile, the right plate has 25 holes which represent seasonal night 5-hours (Kyeong) and their 5-subhours (Jeom), not 12 hours. There are 11 scheduled plates for seasonal night 5-hours made with copper, which are made to be attached or detached as the season. In accordance with Nujutongui (manual for the operation of the yardstick for the clepsydra), the first scheduled plate for the night is used from the winter solstice (冬至) to 2 days after Daehan (大寒), and from 4 days before Soseol (小雪) to a day before the winter solstice. Besides the first scheduled plate, we confirm discovering a third scheduled plate and a sixth scheduled plate among the excavated copper materials based on the spacing between holes. On the other hand, the width of the scheduled plate is different for these artifacts, measured as 144 mm compared to the description of the Borugak Pavilion, which is recorded as 51 mm. From this perspective, they may be the scheduled plates for the Heumgyeonggak Ongru made in 1438 (or 1554) or for the new Fortress Pavilion installed in Changdeokgung palace completed in 1536 (the 31^st year of the reign of King Jungjong) in the early Joseon dynasty. This study presents the concept of the scheduled plates described in the literature, including their new operating mechanism. In addition, a detailed model of 11 scheduled plates is designed from the records and on the excavated relics. It is expected that this study will aid in efforts to restore and reconstruct the automatic water clocks of the early Joseon dynasty.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.33-38
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• 2021

Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.557-564
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• 2021

Sr_0.92Y_0.08Ti_1-xV_xO_3-δ (SYTV) with perovskite structure was investigated as an alternative anode to utilize H₂S containing fuels in solid oxide fuel cells. To improve the electrochemical performance of Sr_0.92Y_0.08TiO_3-δ (SYT), vanadium(V) was substituted to titanium(Ti) at the B-site of the SYT perovskites. The SYTV synthesized by the Pechini method was chemically compatible with the YSZ electrolyte without additional by-products formation under the cell fabricating conditions. As increasing V substitution amounts, the oxygen vacancies increased, resulting to increasing ionic conductivity of the anode. The cell performance in pure H₂ at 850 ℃ is 19.30 mW/cm² and 34.87 mW/cm² for a 1 mol.% and 7 mol.% of V substituted anodes, respectively. The cell performance using H₂ fuel containing 1000 ppm of H₂S at 850 ℃ was 23.37 mW/cm² and 73.11 mW/cm² for a 1 mol.% and 7 mol.% of V substituted anodes, respectively.

• Journal of Korean Philosophical Society
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• v.147
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• pp.333-356
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• 2018

Shang Yang was a person who, as a representative of the former School of Law, not only had an effect of thought on Han Fei Tzu, but also put a cornerstone of Qin Shi Huang's great universal unification by placing small and weak Qin Dynasty in a border area in the rank of a newly rising powerful nation. He is especially regarded as a person who valued laws and established the theoretical framework of legalist thought of School of Law systematically. To begin with, this writing examines the contents of the enforcement of legal reforms relevant to the prerequisite of Shang Yang's legal thought in historical archives, and confirms that Shang Yang succeeded in accomplishing legal reforms twice and that the aim of the legal reforms was to realize national prosperity and military power for the universal unification. This writing also takes notice of the fact that Shang Yang's legal thought went through specific steps for unifying the legal authority and the power of the monarch. Especially this writing focuses on applying the three-step theory of norms that was presented in the western social and political norm theory to Shang Yang's legal thought and on examining the characteristic and meaning explicitly. In short, the social and political norms go through emergence, cascade, and internalization. This writing aims to confirm that Shang Yang's legal thought also went through these three steps and was specified. Specifying this critical mind, this writing is a result which discusses that Shang Yang's legal thought went though the steps of the selective prescriptivism of emergence, the monarchical absolutism through sever punishment, and the internal monarchism for national prosperity and military power, and that the thought was systemized. Finding that the contents of Shang Yang's legal thought correspond to the three-step theory of norms and produce the individual meaning is the independent characteristic of this writing. It is the aim of this writing that the system and meaning of Shang Yang's legal thought will be confirmed more explicitly through this contextual examination.

• Korean Journal of Heritage: History & Science
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• v.51 no.3
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• pp.104-121
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• 2018

The purpose of this paper is to contribute to a more comprehensive understanding of the Buddhist art in Jeju which has rarely been in the mainstream discussions about the Korean art by focusing on the statues of Jabok Mireuk, or Maitreya of Wealth and Fortune. The Buddhist art in Jeju reached its heyday during the late phase of the Goryeo period (918-1392). The imperial court of Yuan (1271-1368) established Beophwasa, one of its guardian temples which was also a "complementary temple" of Goryeo (918-1392). In 1296, the community of monks based in Myoryeonsa Temple published the Jeju edition of the Buddhist canon granted by the royal court of Goryeo, contributing to the foundation of the island's academic culture. Other items representing the heyday of the Buddhist art of Jeju include the Vajra Guardian carved on the greenschist pagoda of Sujeongsa Temple built during the late Goryeo period and the Five-story Stone Pagoda of Bultapsa Temple made from the locally obtained basalt rock during the early $14^{th}$ century. The Buddhist art of Jeju during the Joseon period (1392-1910) is represented by Jabok Mireuk, or Maitreya of Wealth and Fortune, a pair of stone statues of Maitreya Buddha carved to feature three aspects of the Maitreya worship spread among the local folks in the period. Each of the statues is in a peaked cap and official's robe and characterized by bulging eyes comparable to those of the Buddhist guardian deities such as the Vajra guardian who were designed to protect a sacred area against evil forces. The Maitreya statues provide valuable sources of knowledge about the types of Maitreya adopted by the worshippers of local folk religion in the Joseon period. The Jabok Mireuk statues in Jeju can be easily compared with the Two Rock-carved Standing Buddhas in Yongmi-ri, Paju (1471), and the two standing stone Buddhas in Daeseongsa Temple in Okcheon (ca 1491) and on the Sipsinsa Temple site in Gwangju in that they all wear peaked caps in the "treasure canopy" style which gained popularity during the early Joseon period. One may conclude then that these statues are related with the Neo-Confucian elites who wanted the Joseon dynasty they established to prosper under the auspices of the Buddha of the Future. Interestingly, the enshrinement of the stone Buddha of Daeseongsa Temple is presumed to have been participated by Yuk Han who had served as the Governor (Moksa) of Jeju, suggesting its connection with the Jabok Mireuk despite the regional difference in their style.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.44-65
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• 2018

This study examined the costumes of the characters in the painting titled Hig yongru Banghwoedo, which was designated as National Treasure No. 1879 in September 2015, and is currently kept in the Dongguk University Museum. The painting depicts a social gathering of Joseon aristocrats held at the higyongru, or watch tower, of the Gwangjumok, a government office, in 1567. It is characterized by the delicate illustration of the government officials, the main characters of the gathering, and the hyangri, ajeon, najang, chorye, akgong, and yeogi, the lower-class employees of the office. In order to investigate the costumes they wore, diverse materials including literature, costume artifacts, and paintings were used as reference sources. The scope of the study was limited to the characters' headdress and gown, and the accessories attached to the former. The study of men's clothing revealed that officials wore a samo and a red dalryeong as basic attire. In addition, it is presumed that they wore a belt indicating their official rank in the hierarchy, and a pair of black shoes. Retired officials wore a heuklip wrapped in horsehair or silk fabric with a red jing-nyeong and a doah. The hyangri wore a heukjukbanglip on their head, as well as a white jing-nyeong and a belted doah. In the Goryeo period, the banglip was a type of official headdress worn by members of the aristocratic elite ranked immediately below the king, but in Joseon it was demoted as the official headgear of the hyangri class, which was confirmed through Higyongru Banghwoedo. The ajeon wore a heuklip on their head, and a white jing-nyeong and a doah at the waist. As a rule, the najang wore a chogun on the head, and a banbieui on cheolrik and chungmokdai, but the najang in Higyongru Banghwoedo are depicted wearing a chogun and a cheolrik without a banbieui. Also, the chorye wore a heuklip wrapped in hemp cloth with a red cheolrik, whereas the akgong wore a somoja and a red cheolrik. Female entertainers, both adults and children, are depicted in the painting as either serving the aristocrats, dancing, or playing a musical instrument, wearing their hair in a voluminous, round, high bun, and dressed in a red daiyo, a hwangjangsam with a straight or reclined collar, and a belt. Notably, the donggi, i.e. young gisaeng, are shown wearing their hair in two short braids, and ddressed in a red gown with a y-shaped collar, or po.