• Title/Summary/Keyword: Characteristics of development

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Mixing Characteristics of Kerosene-Lox in a Swirl Injector at 100 bar

  • Heo, Junyoung;Kang, Jeongseok;Sung, Hong-Gye
    • International Journal of Aerospace System Engineering
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    • 제3권1호
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    • pp.30-38
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    • 2016
  • The The turbulent mixing characteristics of Kerosene-LOx in a coaxial swirl injector 100 bar have been numerically investigated. Turbulent model is based on large eddy simulation with real-fluid transport and thermodynamics. The effects of equation of state (EOS), chamber pressure are evaluated in a point of the mixing efficiency and pressure fluctuations. The dominant frequency is same as the hairpin vortex shedding frequency generated by film wave at the LOx post.

고품질 쌀의 품종별 영양성분 및 취반 특성 (Nutritional Components and Cooking Characteristics of High Quality Rice)

  • 우관식;이석기;이병원;김정주;이지혜;이유영;이병규;김현주
    • 한국식품영양학회지
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    • 제31권2호
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    • pp.278-283
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    • 2018
  • The objective of this study was to evaluate quality properties of high quality rice. Seven rice varieties, Dabo, Daebo, Samkwang, Sindongjin, Sukwang, Jinsumi, and Haiami, were investigated for proximate contents and physicochemical characteristics. Moisture content was highest in the Jinsumi (13.13%). Protein and lipid content was highest in the Haiami. The amylose content of the rice cultivars was 20.15~22.51%. The degree of amylopectin polymerization (DP) was analyzed, and in all cultivars, DP 13-24 content was found to be highest, at more than 53%, whereas DP ${\geq}37$ content was lowest, at less than 5.81%. With regard to free sugar, maltose content in rice was the highest (${\geq}46%$). Toyo value of rice was highest in Samkwang, Daebo, and Jimsumi. Palatability characteristics were highest in Daebo and Jimsumi. Thus, the results of this study suggested that Samkwang, Daebo, and Jinsumi can be effectively used as processed cooked rice, though further studies should be required regarding changes in the quality of rice after cooking.

다중출력 LLC 공진 컨버터의 교차 조절 특성 분석 (Analysis of Cross-Regulation Characteristics for Multi-Output LLC Resonant Converter)

  • 정진우;임정규;김종해;오동성;정세교
    • 전력전자학회논문지
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    • 제17권4호
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    • pp.281-290
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    • 2012
  • This paper describes a Cross-regulation characteristics of a multi-output LLC resonant converter widely used in consumer electronics. The output characteristics of the multi-output LLC converter is derived from the assumption that the current and voltage in the resonant network is sinusoidal and the duty loss exists. The simulation and experimental results are provided to verify the theoretic results.

부산항의 개발단계별 수질환경변동특성에 관한 연구 (On the Characteristics of the Water Quality Changes due to the Development Phases of Pusan Port)

  • 고영찬;김종인;류청로
    • 한국해양공학회지
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    • 제14권3호
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    • pp.11-19
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    • 2000
  • This study aims to examine the characteristics of the water quality variation in relation to the change of water exchange rate with respect to the development phases of the Pusan port. To clarify the characteristics, water exchange caused by the variations of coastline shape and water surface area was examined by the numerical experiments using the Lagrangian particle tracking model based on 2-D shallow water equation. As the results of numerical experiments, it was proved that the water exchange in the Pusan port was decreased mainly due to the port development and the breakwaters construction. During the port development phases from 1875 to 1998, 35% of the sea-space in the port had decreased to make hinterland spaces. This resulted in the loss of wet-land and coastline change as well as decrease of the water exchange rate at the sea side. The city population in that period had rapidly increased from several thousands to 4 millions, resulting in the large discharge of sewages into the port area. Under the these environmental conditions, it can be clearly said that the water quality in the Pusan port is sensitively affected by the discharge of urban sewages decrease of the water exchange rate in relation to port and urban developments. In the study, the temporal changes of water quality were discussed with respect to the port development phases. It was clear that the water quality wad controlled by the exchange rate change under the port development as well as the input impact into the port from the urbanized city area. To make clean sea of the Pusan port, it is suggested that the sewage control, the water exchange and coastline control should be systematically checked under the concept of eco-friendly development and environmental management.

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Relationship of Physicochemical Characteristics and Ethanol Yield of Korean Barley (Hordeum vulgare L.) Cultivars

  • Lee, Mi-Ja;Kim, Yang-Kil;Park, Jong Chul;Kim, Young-Jin;Kim, Kyeong-Hoon;Choi, Induck;Choi, Jae-Seong;Kim, Kee-Jong;Kim, Hyung-Soon
    • 한국작물학회지
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    • 제57권4호
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    • pp.401-408
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    • 2012
  • The grain and agronomic characteristics of Korean barley cultivars were investigated with respect to ethanol yield. Test weight, grain yield, and starch yield showed noticeable variation among the cultivars. Grain yields were higher in covered barley and non-waxy barley. Starch yield was higher in non-waxy barley than waxy barley. Protein, ${\beta}$-glucan, and starch content of tested cultivars ranged in 10.0-12.9%, 4.4-7.5% and 49.7-65.3%, respectively. Naked barley cultivar had higher starch content than covered barley cultivar. However, covered barley had high starch yield because it has higher grain yield than naked barley. Covered barley cultivar had higher husk content, ranging 7.6-14.0%, than that of naked barley cultivar, ranging 5.3-8.0%. Starch content was positively correlated with amylose content, test weight, ethanol yield and negatively correlated with protein, husk, ${\beta}$-glucan content. Ethanol yield per ton was positively correlated with starch content, but negatively correlated with husk content. Ethanol yield per hectare was positively correlated with starch yield, grain yield, grain weight and negatively correlated with protein, test weight. From this research, the important characteristics of barley cultivar as a bioethanol producing material were starch content and grain yield. Optimum barley genotype was non-waxy naked barley that had low protein, ${\beta}$-glucan, husk content, and high starch content and grain yield.

전동차용 고성능 AC구동시스템의 개발 (A High Performance AC Propulsion System for Electric Car)

  • 정기찬;방이석;김두식;서광덕;김남해
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 A
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    • pp.278-280
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    • 1996
  • This paper presents a high performance AC propulsion system for electric car to improve traction capability. The presented VVVF inverter was composed of as GTO thyristor and the the controller was fully digitalized by using 32bit DSP. The improved PWM algorithms and the new adhesion control were adapted to improve traction characteristics. This system could be possible the higher reliability and flexibility. The field test results showed the higher performances characteristics of the presented system.

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초기 청소년기의 방과후 활동과 학업성취 및 사회적 발달 (After-School Activities of Preadolescents, Academic Achievements and social Development)

  • 김미해;옥경희;천희영
    • 대한가정학회지
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    • 제39권6호
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    • pp.93-108
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    • 2001
  • After-school activities of 817 7th grade children from Kwangju, Busan, and Kumi were studied to determine relations with (a) child, family and contextual variables (b) child's academic achievement and social development. Children were more likely to engage in extracurriculum activites and TV watching than other after-school activities. After-school activities were related to child's, parent's and contextual variables. Child's characteristics related to after-school activities were sex, impulse control, mastery and self-care. family's characteristics related to after-school activities were mother's employment, emotional support, control, monitoring and SES. Region and regional sagy were related to after-school activities. Some of after-school activities were related child's academic achievement and social development. Especially academic activites have a positive and powerful effects on child's academic achievement and social development.

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