• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.32-39
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• 2011

When the laws about the security of ships are revised, or voyage conditions are changed, ship owners have converted rather than built new passenger ships including cruise ships recently. As conversion causes a lot of changes in principal dimension, structural strength, hydrodynamic performance, the number of passengers, and cargo capacity, detailed pre-review is needed. But any studies on conversion have not been carried out yet, this study investigated and analyzed the trend of consulting companies' reports (Delta Marine Report, 2005, 2008). As a result, it was found that lengthening conversion brought about the main changes in principal dimension, and performance. Also it was suggested that there be factors for consideration like hull scantling, hull form, and cutting point to minimize side effects when ship owners build ships having lengthening conversion in mind.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.87-91
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• 1976

This study was undertaken to learn the over-all influence of fertilizer on soybean culture and the chemical composition of soybean in the reclaimed land. Treatments included five rates of N.P.K: 4.10.8, compost: 1, 000. N.P.K.: 4.10.8 + compost: 1, 000, N.P.K: 2.5.5 kg/10 are as well as unfertilized plot in the reclaimed land and N.P.K: 4.10.8 kg/10 are as a check plot of the cultivated area. The yield of green plant above-ground, grain yield and protein content were higher in the cultivated plot than in the reclaimed land. Maximum yield of green plant or the greatest grain yield occurred in the plot of N.P.K: 4.10.8+compost: 1, 000 kg application and they diminished as the fertilizer application decreased. Yet there was no statistical significance in the chemical seed composition among treatments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.923-929
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• 2019

The stability of the propulsion system is crucial for the autonomous vessel. Multiple power generation and propulsion systems should be provided for the stability of the propulsion system. High power generation capacity is calculated for stability, resulting in economical decline due to low load operation. To solve this problem, we need to optimize the power system. In this paper, an OPMS for electric propulsion ship is constructed. The OPMS consists of a hybrid power generation system, an energy storage system, and a control load system. The power generation system consists of a dual fuel engine, the energy storage system is a battery, and the control load system consists of the propulsion load, continuous load, intermittent load, cargo part load and deck machine load. The power system was constructed by modeling the characteristics of each system. For the experiment, a scenario based on ship operation was prepared and the stability and economical efficiency were compared with existing electric propulsion ships.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.253-255
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• 2021

경찰청 자료에 따르면 한국에서 사망 교통 사고의 75.5%는 화물차 사고이다. 한국에서 화물차 사고로 숨지는 사람은 매년 약 1000명이며, 매일 2~3명이 화물차 사고로 사망한다. 한국의 화물노동자들은 화물차 사고가 끊이지 않는 이유로 열악한 노동조건을 응답하고 있다. COVID 19는 비대면 물류 수요를 증가시키고 있다. COVID 19로 인하여 급격하게 증가한 물류 수요는 기존의 낙후된 물류 기술과 낙후된 물류 시스템으로 인하여 운송 과정의 비효율성을 나타내고 있다. 이러한 한국 운송 시스템의 비효율성은 영세 물류 개인 사업자들에 대한 과도한 업무 부담으로 이어지고 있으며, 한국 운송 시스템의 비효율성은 2020년 이후 급격하게 증가한 물류 산업 재해 사망자 수로 나타나고 있다. CIPs에 입주한 한국 중소 기업들은 별도의 스마트 출입 인증 시스템을 갖추지 못하고 있는 경우가 많으며, 이로 인하여 최종 목적지인 출입 단계에서 많은 운송 시간들이 낭비되고 있다. 스마트 출입 인증 시스템 아키텍쳐를 통하여 영세 물류 개인 택배 사업자는 법적 안정성 개선 효과를 얻을 수 있으며, CIPs 중소 기업들은 물류 운송 시간을 단축하는 효과를 얻을 수 있다. CIPs스마트 출입 시스템은 현재 활성화되어 있는 Mobile OTP를 활용하므로, 시스템 설계 비용을 크게 절감할 수 있으며, 개별 휴대폰 단말기에 발생하는 Data용량 부담을 크게 줄이고, 개별 휴대폰 단말기의 응답 속도를 개선할 수 있다. 또한 기존에 다양하게 활용되던 OTP 체계와 호환성이 있으며, OTP 시스템의 오랜 사용 기간을 통한 시스템 신뢰성도 높다. 사용자 고객들의 OTP 시스템 이해도도 다른 스마트 출입 시스템에 비하여 높다.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.423-429
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• 2008

Currently, Ash-free clean coal producing process by solvent extraction is under development. The produced ash-free clean coal can be directly combusted in a gas turbine which results in substantial improvement of power generation efficiency. However, the clean coal produced by the solvent extraction still contain trace amount of alkali metal which may cause corrosion on turbine blades during the direct combustion. In present work ${\alpha},{\beta}$-metal (Zr and Ti) phosphates and H-Y zeolite were synthesized and their ion exchange characterizations were investigated for the application on alkali metal removal for clean coal production. $Na^+$ ion removal capacities of the metal phosphates and H-Y zeolite were measured and compared in both aqueous solution (100 ppmw, $Na^+$) and coal dissolved N-methyl-2-pyrrolidone (NMP, 12 ppmw $Na^+$) at elevated temperature. In aqueous solution, the ${\beta}$ form metal phosphates showed very high ion exchange capacities compared to ${\alpha}$ form. ${\beta}$ form metal phosphates also showed higher $Na^+$ removal capacities than H-Y zeolite. In ion exchange medium of NMP, all the ${\alpha}$ form metal phosphates showed over 90% of $Na^+$ ion removal efficiency in the temperature range of 200 to 400 while that of H-Y zeolite decreased as a half when the temperature was over 350. In addition, the regenerated metal phosphates by acid treatment showed no sign of degradation in $Na^+$ removal efficiency. Among the metal phosphates used, $Zr_{0.75}Ti_{0.25}(HPO_4)_2$ showed the best performance in $Na^+$ removal and is expected to be the most suitable inorganic ion exchanger for the alkali metal removal process.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.514-520
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• 1996

To clarify the proper nitrogen application level for rasing rice infant seedling under different nursery soil, Dongjinbyeo was raised at seedling box with different basal nitrogen level. The results are as follows. The higher the nitrogen level was, the lower emergence rate and the lower establishment rate. The establishment rate was less than 90%, when the nitrogen was more than 2g/box in hill soil and more than 1g/box in paddy soil. The more the nitrogen level was, the higher the seedling height in hill soil, but was higher in the order of N-2, 3, 1 and 0g /box. Leaf number wasn't significantly different between nusery soils and among nitrogen levels when seedling was raised more than 6 days. The endosperm survival rate was decreased as the increased nitrogen level, but wasn't different between the nursery soils. Amount of root was decreased as the increased nitrogen level in paddy soil, but was heavier in the order of N-1, 0, 2 and 3g /box in hill soil. Mat formation was better as the nitrogen level was decreased in all nursery soils. Considering the emergence rate, seedling charactors and mat formation, the proper nitrogen levels seemed to be 2g /box for hill soil and 1g /box for paddy soil.

• Journal of the Korean Electrochemical Society
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• v.20 no.1
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• pp.7-12
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• 2017

Using a precursor of $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ as a starting material, a surface-modified cathode material was obtained by coating with KCl, where the added KCl reduces residual Li compounds such as $Li_2CO_3$ and LiOH, on the surface. The resulting electrochemical properties were investigated. The amounts of $Li_2CO_3$ and LiOH decreased from 8,464 ppm to 1,639 ppm and from 8,088 ppm to 6,287 ppm, respectively, with 1 wt% KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ that had been calcined at $800^{\circ}C$. X-ray diffraction results revealed that 1 wt% of KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ did not affect the parent structure but enhanced the development of hexagonal crystallites. Additionally, the charge transfer resistance ($R_{ct}$) decreased dramatically from $225{\Omega}$ to $99{\Omega}$, and the discharge capacity increased to 182.73mAh/g. Using atomic force microscopy, we observed that the surface area decreased by half because of the exothermic heat released by the Li residues. The reduced surface area protects the cathode material from reacting with the electrolyte and hinders the development of a solid electrolyte interphase (SEI) film on the surface of the oxide particles. Finally, we found that the introduction of KCl into $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ is a very effective method of enhancing the electrochemical properties of this active material by reducing the residual Li. To the best of our knowledge, this report is the first to demonstrate this phenomenon.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.97-102
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• 2020

Recently, various degradation mechanisms of lithium secondary battery cathode materials have been revealed. As a result, many studies on overcoming the limitation of cathode materials and realizing new electrochemical properties by controlling the degradation mechanism have been reported. Li-rich layered oxide is one of the most promising cathode materials due to its high reversible capacity. However, the utilization of Li-rich layered oxide has been restricted, because it undergoes a unique atomic structure change during the cycle, in turn resulting in unwanted electrochemical degradations. To understand an atomic structure deterioration mechanism and suggest a research direction of Li-rich layered oxide, we deeply evaluated the atomic structure of 0.4Li₂MnO₃_0.6LiNi_1/3Co_1/3Mn_1/3O₂ Li-rich layered oxide during electrochemical cycles, by using an atomic-resolution analysis tool. During a charge process, Li-rich materials undergo a cation migration of transition metal ions from transition metal slab to lithium slab due to the structural instability from lithium vacancies. As a result, the partial structural degradation leads to discharge voltage drop, which is the biggest drawback of Li-rich materials.

• Journal of the Korean Electrochemical Society
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• v.9 no.1
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• pp.1-5
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• 2006

Lithium titanium oxide $(Li_4Ti_5O_{12})$ with spinel-framework structures as anode material for lithium-ion battery was prepared by sol-gel and high energy ball milling (HEBH) method. According to the X-ray diffraction (XRD), Particle Size Analyses(PSA) and scanning electron microscopy (SEM) analysis, uniformly distributed $Li_4Ti_5O_{12}$ particles with grain sizes of 100 nm were observed. Half cells, consisting of $Li_4Ti_5O_{12}$ as working electrode and lithium foil as both counter and reference electrodes showed the high performance of high rate discharge capacity and 173 mAh/g at 0.2C in the range of $1.0\sim2.5 V$. Furthermore, the crystalline structure of $Li_4Ti_5O_{12}$ didn't transform during the lithium intercalation and deintercalation process.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.314-320
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• 1984

Effects of phosphorous fertilizer on the growth habit and yield of monoculm and branch types of two leading sesame varieties was investigated. The photosynthetic rate of at each growing stage was high at the flowering stage. The photosynthetic rate of monoculm sesame variety, Pungnyeon was high prior to flowering stage, while the Kwangsan variety, branch type was high after the flowering stage. The level of phosphate were most effective in increasing photosynthesis when standard level of fertilizer was applied in both varieties. Kwangsan variety showed higher photosynthetic rate per unit area, higher NAR, and CGR and higher LAR and RGR at the maximum flowering stage than the Pungnyoeon variety. Those characters attained maximum level when standard levels of phosphorous fertilizer were applied. The protein and oil content of seeds were higher in Kwangsan variety compared with Pungnyeon. However, the carbohydrate of seeds was high for Pungnyeon variety. The highest protein content was attained when standard level of fertilizer were applied. The oil content appeared to increase as the level of applied fertilizer increased. The results suggest that the vegetative growth and seed yields of sesame may be enough with present level of fertilizers. However, higher amount of phosphorous fertilizer may be required to increase the oil content of sesame seeds.