• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.151-151
• /
• 2022

The impact of raindrops on the soil surface causes soil detachment, which may be estimated by measuring the kinetic energy (KE) of the raindrops. Since direct measurements of rainfall force on ground surfaces are not generally available, empirical equations are an alternative option to estimate KE from rainfall intensity (I), which has the greatest influence over soil erosion and is easily accessible. Establishing the optimal formulation for the relationship between kinetic energy and rainfall intensity has proven to be difficult. Thus, this research considered thirty-seven rainfall events observed from June 2020 to December 2021 using a laster optical disdrometer erected in Kyungpook National University to examine the characteristics of KE-I relationships. We concentrated our discussion on the formation of two different expressions of the KE, including KE expenditure (KE_exp) and KE content (KE_con). The following conclusions were drawn: (1) We employed statistical analysis to demonstrate that the KE_exp is more suitable expression for establishing an empirical rule between KE and I than the KE_con. (2) A power-law model was used to find the best correlation between KE_exp-I relationship, whereas the best match between KE_con and I were found using an exponential equation.

• Journal of Animal Science and Technology
• /
• 제63권2호
• /
• pp.354-366
• /
• 2021

Limited data about the effects of various factors on forage quality and β-carotene content of rye produced in Korea are available, so this study investigated the effects of two preservation methods. Samples were collected from rye harvested every 5 days between April 25 and May 31, and comparisons were done among rye silage wilted for different periods of time and hay of three growth stages of rye. For the silage, dry matter (DM), acid detergent fiber (ADF), and neutral detergent fiber (NDF) contents increased with advanced maturity of rye, whereas crude protein, in vitro dry matter digestibility (IVDMD), total digestible nutrients (TDN), relative feed value (RFV), and DM loss decreased (p < 0.0001). Wilting increased the DM content and pH value significantly (p < 0.0001). Silage harvested at the heading stage had the lowest pH value (4.45), propionic acid (0.83 g/kg DM), butyric acid (0 g/kg DM), and fungi and yeast populations (3.70 Log CFU/g of fresh matter [FM]); conversely, it had the highest lactic acid (9.7 g/kg DM), lactic acid bacteria (LAB) (6.87 Log CFU/g of FM), total microorganisms (TM) (7.33 Log CFU/g of FM), and Flieg's score (70) (p < 0.0001). Wilting elevated LAB and TM populations, but it had no consistent effect on other fermentation products. Both delayed harvest and prolonged wilting decreased β-carotene content. Rye silage harvested around May 9 (heading stage) with 24 h of wilting was preferred for highland, Pyeongchang. For rye hay, advanced maturity decreased DM loss, IVDMD, TDN, and RFV, but it increased DM, ADF, and NDF significantly (p < 0.05). β-carotene was decreased by delay of hay-making. Consequently, to attain lower DM loss and higher hay quality, the harvest date of May 9 (heading stage) is recommended.

• Journal of Microbiology and Biotechnology
• /
• 제32권3호
• /
• pp.378-386
• /
• 2022

Scenedesmus obliquus ABC-009 is a microalgal strain that accumulates large amounts of lutein, particularly when subjected to growth-limiting conditions. Here, the performance of this strain was evaluated for the simultaneous production of lutein and biofuels under three different modes of cultivation - photoautotrophic mode using BG-11 medium with air or 2% CO₂ and heterotrophic mode using YM medium. While it was found that the highest fatty acid methyl ester (FAME) level and lutein content per biomass (%) were achieved in BG-11 medium with CO₂ and air, respectively, heterotrophic cultivation resulted in much higher biomass productivity. While the cell concentrations of the cultures grown under BG-11 and CO₂ were largely similar to those grown in YM medium, the disparity in the biomass yield was largely attributed to the larger cell volume in heterotrophically cultivated cells. Post-cultivation light treatment was found to further enhance the biomass productivity in all three cases and lutein content in heterotrophic conditions. Consequently, the maximum biomass (757.14 ± 20.20 mg/l/d), FAME (92.78 ± 0.08 mg/l/d), and lutein (1.006 ± 0.23 mg/l/d) productivities were obtained under heterotrophic cultivation. Next, large-scale lutein production using microalgae was demonstrated using a 1-ton open raceway pond cultivation system and a low-cost fertilizer (Eco-Sol). The overall biomass yields were similar in both media, while slightly higher lutein content was obtained using the fertilizer owing to the higher nitrogen content.

• Journal of Information Technology Applications and Management
• /
• 제28권1호
• /
• pp.53-61
• /
• 2021

The year 2020 was a time when the coronavirus infections-19 (COVID-19) caused various changes in society. In particular, the fields that have been conducted face-to-face have been greatly confused by the transition to an online non-face-to-face method, and this is the case with the field of education. There are two main advantages of offline education. The first is that we can improve our understanding through communication with teachers, and the second is that we can develop social skills through interaction with friends. But as online classes progressed due to corona 19, interaction could not be achieved. As a result, the motivation for learning has been reduced due to difficulties in real-time feedback, and the participation rate has been significantly lowered, especially in lower grades, raising concerns about the learning gap that will occur after corona 19. However, there are some cases in which online classes were conducted as effectively as offline classes by utilizing various contents. What they have in common is the use of content. Teachers generally improved the quality of education by linking interesting sights and videos that enhance learning comprehension. The provided video conveys learning-related content into stories, enabling intuitive observation. Many students were already enjoying these videos through VOD (Video on Demand) such as TV and YouTube, they were able to connect their easy access to content and interest in learning. Appropriate use of video content has rather increased the learning effect and should continue after corona 19. Therefore, it is necessary to study methodologies that apply video content efficiently to education. This study looked at the steps that needed content application through the development of education programs, and observed its meaning. Students were curious about the content, motivated to learn and participated in learning on their own. Intuitive learning, conducted through appreciation, play and content production, provided an opportunity to learn on their own in everyday life.

• 한국식품조리과학회지
• /
• 제23권5호
• /
• pp.671-676
• /
• 2007

The effect of solid content on the physicochemical properties of rice porridge after reheating. The concentration of rice porridge was classified as solid content (12%, 10%, and 8%) by traditional Korean cooking methods. For reheating, packed rice porridge was boiled in water for 3 min and then cooled at room temperature ($25^{\circ}C$). The viscosity, soluble solid content and reducing sugar content of the rice porridge increased according to the solid content, while the blue value decreased. After reheating, the viscosities ($25^{\circ}C$) of all rice porridges decreased to 2.9-8.4%, compared to those of freshly made rice porridge, whereas the soluble solid content and reducing sugar content increased inversely according to the solid content of rice porridge. The SDI (starch digestion index) increased according to the solid content, whereas SDS (slowly digestible starch) the lowest in the solid content 12% porridge. Based on these results, it is favorable that the viscosity decrease after reheating was to be considered to ready-to eat rice porridges preparation.

• 방송공학회논문지
• /
• 제27권5호
• /
• pp.654-664
• /
• 2022

실감 콘텐츠는 COVID-19 팬데믹으로 인한 관심과 더불어 확장현실, 인공지능, 포토그래메트리 기술과 융합을 통해 공간적 한계를 극복하며 엔터테인먼트, 미디어, 공연, 전시 등 콘텐츠 시장에서 새로운 패러다임을 제시하며 수요 역시 증가하고 있다. 하지만 실감 콘텐츠가 대중들에게 지속된 관심을 가지기 위해서는 기술적 신선함보다 콘텐츠에 대한 몰입도를 높일 수 있는 스토리텔링 방법 연구가 필요하다는 것을 알 수 있다. 따라서 본 연구에서는 인공지능 및 포토그래메트리 기술을 활용한 실감 콘텐츠 스토리텔링 방법을 제안한다. 제안된 스토리텔링 방법은 대화형 가상존재와 참여자가 대화를 통한 상호작용으로 콘텐츠 스토리를 생성하는 것이다. 이에 관객 주도적 참여를 통해 콘텐츠 몰입도를 높일 수 있다. 본 연구는 가속화되는 실감 콘텐츠 시장에서 콘텐츠 제작자들에게 제안된 인공지능 기술이 활용된 가상존재를 통한 스토리텔링 방법론으로 효율적인 콘텐츠 제작에 도움을 줄 수 있을 것으로 기대한다. 또한 콘텐츠 제작에 있어 인공지능 및 포토그래메트리 기술을 활용한 실감 콘텐츠 제작 파이프라인 정립에 기여할 것이라고 생각한다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제15권3호
• /
• pp.396-400
• /
• 2002

This study was conducted to evaluate the dry matter (DM) yield, quality and utilization of nutrients in Korean lespedeza (Lespedeza stipulacea Maxim.) swards as a roughage source. DM yield in various stages, chemical composition, and DM digestibility were observed, and DM intake, digestibility and utilization of nitrogen and energy by Korean native goat were determined. Experimental diets include three treatments: mixture hay (MH) 100%, MH (80%)+wild Korean lespedeza hay (LH) 20% and MH (60%)+LH (40%). As growth stage advanced, the DM yield of Korean lespedeza tended to increase significantly (p<0.05). The mean DM yield of all growing stages was observed as 7,336 kg/ha. Crude protein (CP) content of Korean lespedeza tended to decrease, but fibrous contents tended to increase when the growth stage advanced. The tannin content of Korean lespedeza was the highest at the bud stage (64.7 mg/g). However, it showed a tendency to decrease as the growth stage advanced, and thus it was the lowest at the ripe seed stage (26.8 mg/g) (p<0.05). With increasing level of LH, voluntary DM intake by Korean native goats slightly increased, but no differences were observed between diets. The digestibility of DM, cellular constituents and NDF was slightly higher in LH containing diets than that of MH 100% diet (p<0.05). There was no significant difference in apparently digested N% among all diets, but retained N% and retained N% of the absorbed were higher in MH (60%)+LH (40%) than those of other diets (p<0.05). A difference in the utilization of energy was not detected. In conclusion, Juvenile LH improved the digestibility of nutrients, presumably due to its high CP content and low fibrous compound. Especially, tannin in LH did not affect in DM intake, but increased the nitrogen utilization of Korean native goats. Accordingly, it could be suggested that Korean lespedeza has a potential to be provided as a roughage source for Korean native goats.

• Current Photovoltaic Research
• /
• 제1권1호
• /
• pp.38-43
• /
• 2013

$Cu(In,Ga)_3Se_5$ is a candidate material for the top cell of $Cu(In,Ga)Se_2$ tandem cells. This phase is often found at the surface of the $Cu(In,Ga)Se_2$ film during $Cu(In,Ga)Se_2$ cell fabrication, and plays a positive role in $Cu(In,Ga)Se_2$ cell performance. However, the exact properties of the $Cu(In,Ga)_3Se_5$ film have not been extensively studied yet. In this work, $Cu(In,Ga)_3Se_5$ films were fabricated on Mo-coated soda-lime glass substrates by a three-stage co-evaporation process. The Cu content in the film was controlled by varying the deposition time of each stage. X-ray diffraction and Raman spectroscopy analyses showed that, even though the stoichiometric Cu/(In+Ga) ratio is 0.25, $Cu(In,Ga)_3Se_5$ is easily formed in a wide range of Cu content as long as the Cu/(In+Ga) ratio is held below 0.5. The optical band gap of $Cu_{0.3}(In_{0.65}Ga_{0.35})_3Se_5$ composition was found to be 1.35eV. As the Cu/(In+Ga) ratio was decreased further below 0.5, the grain size became smaller and the band gap increased. Unlike the $Cu(In,Ga)Se_2$ solar cell, an external supply of Na with $Na_2S$ deposition further increased the cell efficiency of the $Cu(In,Ga)_3Se_5$ solar cell, indicating that more Na is necessary, in addition to the Na supply from the soda lime glass, to suppress deep level defects in the $Cu(In,Ga)_3Se_5$ film. The cell efficiency of $CdS/Cu(In,Ga)_3Se_5$ was improved from 8.8 to 11.2% by incorporating Na with $Na_2S$ deposition on the CIGS film. The fill factor was significantly improved by the Na incorporation, due to a decrease of deep-level defects.

• 방사선산업학회지
• /
• 제17권3호
• /
• pp.225-232
• /
• 2023

In this study, poly(ethylene-co-vinyl acetate)/magnesium hydroxide (EVA/MDH) composites were prepared by electron beam crosslinking. EVA as a matrix resin and MDH as a flame retardant were melt-blended and compression molded to prepare EVA/MDH composites. The prepared EVA/MDH composites were electron beam-irradiated at various absorbed doses of 50~200kGy. The effects of electron beam irradiation on the gel content, tensile strength, elongation-at-break, thermal properties, and flame retardancy of the composites were investigated. The gel content and tensile strength increased, while the elongation-at-break decreased with an increase in the absorbed dose due to the formation of crosslinked network structures. In addition, the thermal stability and flame retardancy improved as the absorbed dose increased. Therefore, the EVA/MDH composites prepared in this study can be used as an insulation material for flame-retardant and heat-resistant wires and cables.

• Elastomers and Composites
• /
• 제54권1호
• /
• pp.14-21
• /
• 2019

Main-chain/side-chain liquid crystalline polymers (MCSCLCPs) combined with an azobenzene group and a cholesteryl group were synthesized to impart light and temperature sensitivity to the polymer. The polymers were designed with the azobenzene unit as the mesogenic group of the main-chain and various compositions of the azobenzene and cholesteryl units as the mesogenic group of the side-chain. The chemical structures and physical properties of the synthesized polymers were investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, and ultraviolet-visible (UV-Vis) spectroscopy. All the MCSCLCPs were amorphous and exhibited enantiotropic liquid crystal phases; these polymers achieved the nematic phase with increasing content of the azobenzene group and exhibited the cholesteric phase with weak liquid crystallinity as the content of the cholesteryl group was increased. Furthermore, the polymers containing the azobenzene group showed photoisomerization when exposed to UV-Vis light, and the CP-A3C7 and CP-A5C5 polymers exhibited thermochromism in the temperature range of the liquid crystal phase.