• Title/Summary/Keyword: polarization control

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Development of Radar-Based Multi-Sensor Quantitative Precipitation Estimation Technique (레이더기반 다중센서활용 강수추정기술의 개발)

  • Lee, Jae-Kyoung;Kim, Ji-Hyeon;Park, Hye-Sook;Suk, Mi-Kyung
    • Atmosphere
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    • v.24 no.3
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    • pp.433-444
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    • 2014
  • Although the Radar-AWS Rainrate (RAR) calculation system operated by Korea Meteorological Administration estimated precipitation using 2-dimensional composite components of single polarization radars, this system has several limitations in estimating the precipitation accurately. To to overcome limitations of the RAR system, the Korea Meteorological Administration developed and operated the RMQ (Radar-based Multi-sensor Quantitative Precipitation Estimation) system, the improved version of NMQ (National Mosaic and Multi-sensor Quantitative Precipitation Estimation) system of NSSL (National Severe Storms Laboratory) for the Korean Peninsula. This study introduced the RMQ system domestically for the first time and verified the precipitation estimation performance of the RMQ system. The RMQ system consists of 4 main parts as the process of handling the single radar data, merging 3D reflectivity, QPE, and displaying result images. The first process (handling of the single radar data) has the pre-process of a radar data (transformation of data format and quality control), the production of a vertical profile of reflectivity and the correction of bright-band, and the conduction of hydrid scan reflectivity. The next process (merger of 3D reflectivity) produces the 3D composite reflectivity field after correcting the quality controlled single radar reflectivity. The QPE process classifies the precipitation types using multi-sensor information and estimates quantitative precipitation using several Z-R relationships which are proper for precipitation types. This process also corrects the precipitation using the AWS position with local gauge correction technique. The last process displays the final results transformed into images in the web-site. This study also estimated the accuracy of the RMQ system with five events in 2012 summer season and compared the results of the RAR (Radar-AWS Rainrate) and RMQ systems. The RMQ system ($2.36mm\;hr^{-1}$ in RMSE on average) is superior to the RAR system ($8.33mm\;hr^{-1}$ in RMSE) and improved by 73.25% in RMSE and 25.56% in correlation coefficient on average. The precipitation composite field images produced by the RMQ system are almost identical to the AWS (Automatic Weather Statioin) images. Therefore, the RMQ system has contributed to improve the accuracy of precipitation estimation using weather radars and operation of the RMQ system in the work field in future enables to cope with the extreme weather conditions actively.

Performance of EDLC Electrodes Prepared by Post Treatments of Commercial Activated Carbon (상업용 활성탄의 후처리에 의하여 제조된 전기이중층 커패시터용 전극재의 특성)

  • Wu, Jing-Yu;Hong, Ik-Pyo;Kim, Myung-Soo
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.2
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    • pp.362-370
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    • 2013
  • The coconut shell based activated carbon was applied for EDLC (electric double layer capacitor) electrode with the post treatments. The electrochemical properties were evaluated with a coin cell using the activated carbon as electrode. The initial gravimetric and volumetric capacitance of the coconut shell based activated carbon electrode s were 66 F/g and 39 F/cc, and these values decreased to 54 F/g and 32 F/cc after 100 cycles, respectively showing 82% of charge-discharge efficiency. The properties of CV graph with the commercial activated carbon electrodes showed the serious polarization as the result of additional reaction between electrolyte and impurities of the electrode materials. In order to remove impurities efficiently, the commercial activated carbon was treated by alkali and acid solutions consecutively, and then heat treated to control the pore size distribution and the content of surface functional groups. The surface functional groups decreased with the increased heat temperature and the specific capacitance increased with the decreased surface functional groups. The initial capacitance of coconut shell based activated carbon elec trode which was treated with NaOH and HNO3, and then heat treated at $800^{\circ}C$ was 44 F/cc, and the value turned out to be 42 F/cc after 100 cycles, showing over 95% of charge-discharge efficiency.

Optimization of Manufacturing Condition for Fried Garlic Flake and the Physicochemical Properties (튀긴 마늘 flake 제조조건의 최적화 및 이화학적 특성)

  • Kim, Kyeong-Yee;Lee, Eun-Kyung
    • Korean journal of food and cookery science
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    • v.28 no.6
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    • pp.805-811
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    • 2012
  • This study was carried out in order to optimize the manufacturing condition of fried garlic flakes as well as to investigate the physicochemical properties of the flakes. Fried garlic flake samples were prepared as follows: garlic was sliced by a thickness of 1.5 mm, 2.0 mm, 2.5 mm, which were measured by a thickness gage. The samples were fried in vegetable oil under different temperatures of $140{\sim}150^{\circ}C$, $160{\sim}170^{\circ}C$ and $180{\sim}185^{\circ}C$. The compression strength depending on the height (h) was measured in order to find the thickness effect by the rheometer (force control: 50 N, h: 3.25 mm). Moreover, the sample with 1.5 mm thickness showed crisp phenomena of the split compared with the crush shape of the 2.0 mm and 2.5 mm thick samples. The result of strength for time dependence showed a sample with a thickness of 1.5 mm, which was measured 5~9 times more than the 2.0 mm and 2.5 mm thick samples. We thought the reason that the 1.5 mm sample had less response power equivalent to compression force than the other samples. Alliin has been found to affect the immune responses in the blood, it is a derivative of the amino acid cysteine and is also quite heat stable. The LC system with a UV detection at 210 nm consists of a separation on a Zorbax TMS column and isocratic elution with water and ACN as a mobile phase. The alliin contents of raw and fried garlic flake under $140{\sim}150^{\circ}C$, $160{\sim}170^{\circ}C$ and $180{\sim}185^{\circ}C$ were 18.10 mg/mL, 14.0 mg/mL, 11.6 mg/mL and 11.1 mg/mL, respectively. The decrement of alliin content under different temperature was a small quantity hence, we confirmed that the increasing manufacturing temperature was not affected by the alliin content. Examining for the particle structure of fried garlic flakes by a polarization microscope, the color of the sample treated at $160{\sim}170^{\circ}C$ was pure yellow. Furder, the fiber shaped particle, which has an effect on the tough texture, almost did not appear compared to the different temperature conditions. Finally, the sensory test for the preference of fried garlic flake under different conditions was carried out and the scores for various sensory characteristics were surveyed. According to the physicochemical measurements and sensory evaluation, we confirmed that the optimum manufacturing condition of fried garlic flake was 1.5 mm thick at a temperature of $160{\sim}170^{\circ}C$.

Corrosion Properties of Atomic Layer Deposited TiO2, Al2O3 and TiO2-Al2O3 Nanolaminated Film Coated 316L Stainless Steel (원자층 증착법에 의한 TiO2, Al2O3, 및 TiO2-Al2O3 나노라미네이트 박막이 316L Stainless Steel의 부식특성에 미치는 영향)

  • Lee, Woo-Jae;Wan, Zhixin;Kim, Da Young;Jang, Kyung Su;Choi, Hyun-Jin;Choi, Woo-Chang;Kwon, Se Hun
    • Journal of the Korean institute of surface engineering
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    • v.50 no.1
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    • pp.35-41
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    • 2017
  • $TiO_2$, $Al_2O_3$, and $TiO_2-Al_2O_3$ nanolaminated films were grown by atomic layer deposition (ALD) on the 316L stainless steel (SS316L) substrates at a temperature of $150^{\circ}C$. The growth kinetics of $ALD-TiO_2$ and $Al_2O_3$ thin films were systematically investigated in order to precisely control the thickness of each layers in the $TiO_2-Al_2O_3$ nanolaminated films using a high-resolution transmission electron microscopy. And, the exact deposition rates of $ALD-TiO_2$ on $Al_2O_3$ surface and $ALD-Al_2O_3$ on $TiO_2$ surface were revealed to be 0.0284 nm/cycle and 0.11 nm/cycle, respectively. At given growth conditions, the microstructures of $TiO_2$, $Al_2O_3$ and $TiO_2-Al_2O_3$ nanolaminated films were amorphous. The potentiodynamic polarization test revealed that the $TiO_2-Al_2O_3$ nanolaminated film coated SS316L had a best corrosion resistance, although all ALDcoated SS316L exhibited a clear improvement of the corrosion resistance compared with a bare SS316L.

Formation of Provitamin-$B_5$ Liquid Crystal with Hydrogenated Lecithin and Its Effectiveness of Moisturizing Activity (HL에 의한 프로비타민-$B_5$ 액정의 형성과 보습효과)

  • Kim, In-Young;Zhoh, Choon-Koo;Ryoo, Hee-Chang
    • Journal of the Korean Applied Science and Technology
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    • v.20 no.2
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    • pp.101-109
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    • 2003
  • Provitamin $B_5$ liquid crystal ($PVB_5$-LC) was the new emulsion system to enhance moisturizing activity on the skin. In this study, it should be mentioned that PVB5-LC could be prepared with the main compound of hydrogenated lecithin (HL) in oil-in water (O/W) emulsion. The key ingredient of humectants was contained 2% of provitamin $B_5$ ($PVB_5$) into the $PVB_5$-LC. The best suitable compositions of $PVB_5$-LC were made from 4.0 wt% of HL, 4.0 wt% of cetostearyl alcohol (CSA) as emulsifier and gelling agent, 3.0 wt% of 1,3-butylene glycol (1,3-BG) and 2.0 wt% of glycerin as moisturizers, 3.0 wt% of cyclomethicone (CMC), 3.0 wt% of isononanoate (ININ), 3.0 wt% of capric/caprylic triglyceride (CCTG), 3.0 wt% of macadamia nut oil (MNO) as emollients. As the analytical result of $PVB_5$-LC, it could know that the distribution range of particle size was 0.14 to 12.37 m level (mean size 3.24 m). It was certified the multi lamellar phase around the droplet of liquid crystal when observed the droplet particles through a polarization microscope. And it clinically was tested the effectiveness of moisturizing activity (in-vivo) compared with control sample (O/W emulsion). The effectiveness of moisturizing activity of $PVB_5$-LC with Skincon-200EX after 6 hours went up 49.0% (p<0.05, n=20) whereas the effectiveness of moisturizing activity of generally O/W emulsion cream was 25.7% (p<005, n=20). Also, in case of Comeometer CM-825, the moisturizing activity of $PVB_5$-LC after 6 hours rose 36.6% (p<0.05, n=20) whereas the effectiveness of moisturizing activity of generally O/W emulsion cream was 10.8%. Therefore, it was known that the effectiveness moisturizing activity of $PVB_5$-LC with HL was remarkably superior compared with O/W emulsion cream.

Preparation and Characteristics of High Performance Cathode for Anode-Supported Solid Oxide Fuel Cell (연료극 지지체식 고체산화물 연료전지용 고성능 공기극 제조 및 특성 연구)

  • Song, Rak-Hyun
    • Journal of the Korean Electrochemical Society
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    • v.8 no.2
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    • pp.88-93
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    • 2005
  • Anode-supported solid oxide fuel cell (SOFC) was investigated to increase the cell power density at intermediate temperature through control of the cathode structure. The anode-supported SOFC cell were fabricated by wet process, in which the electrolyte of $8mol\%\;Y_2O_3-stabilized\;ZrO_2 (YSZ)$ was coated on the surface of anode support of Ni/YSA and then the cathode was coated. The cathode has two- or three- layered structure composed of $(La_{0.85}Sr_{0.15})_{0.9}MnO_{3-x}(LSM),\;LSM/YS$ composite (LY), and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3{LSCF)$ with different thickness. Their single cells with different cathode structures were characterized by measuring the cell performance and ac impedance in the temperature range of 600 to $800^{\circ}C$ in humidified hydrogen with $3\%$ water and air. The cell with $LY\;9{\mu}m/LSM\;9{\mu}m/LSCF\;17{\mu}m$ showed best performance of $590mW/cm^2$, which was attributed to low polarization resistance due to LY and to low interfacial resistance due to LSCF.

Development of real-time program correcting error in radar polarimetric variables (실시간 레이더 편파변수 오차 보정 프로그램 개발)

  • Yoon, Jungsoo;Hwang, Seok-Hwan;Kang, Narae;Lee, Dong-Ryul;Lee, Keon-Haeng
    • Journal of Korea Water Resources Association
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    • v.54 no.12
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    • pp.1329-1338
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    • 2021
  • Rain radar provides high spatio-temporal radar rainfall that can be used as input data to short-term precipitation forecasting models. Korea Institute of Civil Engineering and Building Technology (KICT) has developed a flash flood forecasting system that is providing flash flood forecasting based on short-term rainfall forecasts estimated by the radar rainfall. Accuracy of the radar rainfall as well as the short-term rainfall forecasts, however, can deteriorate when radar polarimetric variables have error. In this study, we develope real-time program that can correct the error inherent in the radar polarimetric variables. First, effect according to the correction of the error was verified using 363 rainfall events on non real-time. The accuracy (1-NE) of the radar rainfall was approximately 70% and correlation coefficient was higher than 0.8 after correcting the error on non real-time. The accuracy (1-NE) using the real-time program was also approximately 70% after correcting the error.

Improvement of charging efficiency of AGM lead acid battery through formation pattern research (Formation pattern 연구를 통한 AGM 연축전지의 충전 효율 향상)

  • Kim, Sung Joon;Son, Jeong Hun;Kim, Bong-Gu;Jung, Yeon Gil
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.31 no.1
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    • pp.55-62
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    • 2021
  • In order to improve fuel economy and reduce CO2, HEV adopts ISG system as a standard. This ISG system increased the electric load that the battery had to bear, and the number of starting increased rapidly. AGM Lead Acid batteries have been developed and used, but the charging time is about three times longer as the electrolyte amount control during formation must be maintained at a higher level compared to conventional lead-acid batteries. In this study, we tried to shorten the charging time by increasing the charging efficiency through the optimization of the formation pattern. In order to optimize the Formation Pattern, 10 charging steps and 6 discharging steps were applied to 16 multi steps, and the charging current for each step was controlled, and the test was conducted under 4 conditions (21 hr, 24 hr, 27 hr, 30 hr). As a result of simultaneous application of multi-step and discharge step, it was verified that minimizing the current loss and eliminating the sudden polarization during charging contributes to the improvement of charging efficiency. As a result, it showed excellent results in reducing the charging time by about 30 % with improved charging efficiency compared to the previous one.

Synthesis and Electrochemical Properties of (La0.6Sr0.4)(Co0.2Fe0.8)O3 cathode for SOFC on pH Control Using Modified Oxalate Method (Modified Oxalate Method 의해 합성한 SOFC용(La0.6Sr0.4)(Co0.2Fe0.8)O3 Cathode의 pH 변화에 따른 특성)

  • Lee, Mi-Jai;Choi, Byung-Hyun;Kim, Sei-Ki;Park, Sang-Sun;Lee, Kyung-Hee
    • Journal of the Korean Electrochemical Society
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    • v.10 no.4
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    • pp.288-294
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    • 2007
  • The LSCF cathode far Solid Oxide Fuel Cell was investigated to develop high performance unit cell at intermediate temperature by modified oxalate method with different electrolytes and different pH. The LSCF powders employed La, Sr, Co and Fe oxides, oxalic acid, ethanol and $NH_4OH$ solution were synthesized with pH controlled as 2, 6, 7, 8, 9 and 10 at $80^{\circ}C$ Single crystalline phase was obtained from pH $2{\sim}9$. on the other hand, $La_2O_3$ appeared from pH 10. Very fine powder with particle size of 50 nm was obtained at calcination temperature of $800^{\circ}C$ for 4 hours. LSCF cathode synthesized at pH 7 showed the highest electric conductivity in the temperature range of $600^{\circ}C$ to $900^{\circ}C$ its value was 950 S/cm at $900^{\circ}C$ Under same synthesis conditions, polarization resistance of each LSCF cathode was changed with different calcination temperatures. As-prepared powder presented 2.52, 1.54 and $2.58\;{\Omega}$ at $600^{\circ}C$ with ScSZ, 8Y-YSZ and GDC as its electrolyte respectively after calcination at $800^{\circ}C$ for 4 hours.

The Reinterpretation and its Prospect about Resentment Solution and Coexistence in The 4th Industrial Revolution Era (4차 산업혁명 시대에 있어서 해원상생의 재해석과 지평)

  • Kim, Bang-ryong
    • Journal of the Daesoon Academy of Sciences
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    • v.29
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    • pp.37-68
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    • 2017
  • This paper critically examines the role and function of religion prior to the full-out advent of the 4th industrial revolution. We can understand 'The vision of Daesoon Jinrihoe (大巡眞理會)' as a mission to foresee and create a prospective figure for a future society in the person of the Lord on High, Jeungsan (甑山) as a religious dimension. However, the existence ground of religion relies on giving positive meaning to the present time after reinterpreting religious doctrine to reflect changing realities. Jeungsan (甑山) said that the age to come is 'the age of the human majesty (人尊)'. This means that humans will take the lead and control the revolution of scientific technology to progress and benefit humanity. Problems such as 'human alienatio', 'increased polarization', and 'destruction of the environment' still arise and deepen because the motive of 'the Industrial Revolution' was built upon 'knowledge' within the context of a Knowledge-Based Society. Therefore, we can say that the role of religion will newly rise to the forefront in the era of the 4th industrial revolution. Consequently, religion should face matters squarely and suggest viable alternatives. This paper deals with reinterpreting the concept of 'the resolution of grievances for mutual beneficence (解冤相生)', one of the four teachings of Daesoon Jinrihoe, within the context of the coming era of the 4th industrial revolution. My research is divided into the following three parts: First, I determined the teachings of Daesoon Jinrihoe and the original meaning of 'the resolution of grievances for mutual beneficence', and then I disclosed the way we can reinterpret the general meaning of this concept for application in the ear of the 4th industrial revolution. Second, from the perspective of the religious dimension, I inquired into factors regarding alienation and conflict in the era of the 4th industrial revolution. I focused on human alienation from labor, identity confusion, potential conflicts between humans and post-humans, and the characteristics of the 4th industrial revolution. Third, I examined potential cures for alienation and conflict through the principle of the resolution of grievances for mutual beneficence. I tried to enlarge the interpretive prospects of Daesoon's main teaching in light of the era of the 4th industrial revolution through a new interpretation and application that employs the concept of 'the resolution of grievances for mutual beneficence (解冤相生)' in order to cure the alienation and conflict.