• Title/Summary/Keyword: 정동역학

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Development of for Mineral Salt Manufacturing System using Deep Sea Water (해양 심층수를 이용한 미네랄소금 제염장치 개발)

  • Kim H. J.;Shin P. K.;Moon D. H.;Jung D. H.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.183-189
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    • 2004
  • Deep ocean water is located in the sea deeper than 200m. At such depth the solar light does not reach, photosynthesis is not performed and nutrition salt is not consumed. Therefore, campared with surface water, Deep Sea Water contains more nutrition salt, such as nitrogen and phosphor. Moreover, it has the good balance of minerals. This Research is primary attempt for apply deep sea water to food industry. New type of mineral salt manufacturing system was developed and high levels of Ca, K, Mg detected from the salt analysis.

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Flow Analysis in an Entrained Flow Combustor (분류층 연소기내의 유동해석)

  • 양희천;박상규;정동화
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.6
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    • pp.1308-1316
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    • 2001
  • This paper described a numerical investigation performed to understand better the effects of flow parameters in an entrained flow combustor on the flow characteristics. The computational model was based on the gas phase Eulerian equations of mass, momentum and energy. The code was formulated with RNG $k-\varepsilon$ model for turbulent flow. The calculation parameters were the ratio of primary and secondary jet velocity and the height difference between primary and secondary jet As the secondary jet velocity increased, the upper recirculation 3one of the primary jet was strengthened. It was found that as the primary jet velocity increased, there was a critical jet Velocity at which the size of upper and lower recirculation zone was reversed.

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Study of the Thrust Vector Control Using a Secondary Flow Injection (2차 유동의 분사에 의한 제트 유동의 추력제어에 관한 연구)

  • 정성재;김희동;안재문;정동호
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2002.04a
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    • pp.14-15
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    • 2002
  • 기체역학 이론에 의하면, 노즐의 공급압력과 노즐의 상세형상이 주어지는 경우에 추진 노즐로부터 방출되는 제트유동의 추력을 예측할 수 있으며, 최대추력은 노즐 출구에서 유동이 적정팽창 상태로 될 때 얻어진다. 실제의 추진 로켓에서나 다른 비상체에서는 추력의 예측뿐만 아니라, 얻어지는 추력의 방향을 적절하게 조절하여 제어하는 것이 요구된다. 종래 추력벡터 제어를 위해서 많은 연구들이 수행되었다. 일례로 추진노즐 내부에 베인(vane) 등을 삽입하여, 추력벡터를 조절하거나, 추진 노즐을 가변(movable nozzle)으로 하는 방법, 그리고 노즐내부에 2차 유동을 분사(secondary flow injection)하여 평균 추력벡터를 제어하는 방법 등이 제안되어 응용되어 왔다.

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High Velocity Impact Simulation Using Explicit Time Integration Finite Element Method (엑스플리시트의 유한요소법을 이용한 고속충돌해석)

  • 정동택
    • Journal of the KSME
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    • v.35 no.8
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    • pp.698-708
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    • 1995
  • 충돌이란 두 개 이상의 물체가 특정한 상대 속도로 부\ulcorner칠 때 나타나는 현상으로서 준 정 적(quasi-static) 조건하에서 나타나는 현상과 크게 다음 두 가지 특징을 들 수 있다. 첫째, 관 성력이 매우 중요하다. 따라서 기본 역학 및 물리학 보존법칙에 기초를 둔 모든 지배 방정식에 이 영향을 반드시 포함시켜야 한다. 둘째, 응력파(stress wave)에 의한 재료의 변형을 들 수 있다. 이 응력파는 시간과 거리에 따라 급격히 감소되므로 대부분의 경우 국부적으로 많은 변형이 일 어난다. 충돌에 의하여 일어나는 재료의 변형 특성은 충돌 속도에 따라 매우 다르게 나타난다. 이러한 특징들을 표 1에 나타내었다. 이 글에서는 충돌 해석 프로그램의 특징과 구성을 소개하고 그중 엑스플리시트 유한요소방법을 사용한 금속 재료에 관련된 몇 가지 충돌현상의 해석 예를 소개하고자 한다.

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Epidemiological survey for avian salmonellosis from broilers in Namwon area (전북 남원지역 육계에서 살모넬라증에 대한 역학적 조사)

  • 정영미;김기주;엄성심;이지영;노영선;서석열;박정배;이희문;정동석
    • Korean Journal of Veterinary Service
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    • v.27 no.1
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    • pp.75-80
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    • 2004
  • This survey was performed to investigate avian salmonellosis from broiler farms in Namwon area for 4 years. The whole samples from farms were 541 and chicken samples were 294. Out of 294, 83 cases were identified with avian salmonellosis for 4 years by various serological and biochemical tests. There was no outbreak of pullorum disease, but fowl typhoid occurred in 36 farms. The outbreak of avian salmonellosis occurred continuously regardless of seasons throughout the year. Avian salmonellosis mostly happened within 10 days of age which were 52 cases(63%). The selection of susceptible antibiotics has changed from Quinoline group in 2000 to amoxacillin + clavulanic acid(AmC).

Doping process design using carrier transport model of sentaurus process (Sentaurus Device simulation의 캐리어 전송 모델을 이용한 도핑 공정 설계)

  • Cho, Chul-Hee;Jung, Hak-Kee;Lee, Jae-Hyung;Jung, Dong-Soo;Lee, Jong-In
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.789-792
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    • 2007
  • 이 연구는 Sentaurus Device를 이용하여 여러 가지 캐리어 전송 모델에 대한 반도체의 구조적, 전기적, 열적 작용의 변화를 조절함으로써 공정과 설계를 보다 쉽게 개발하는데 도움이 되리라 본다. 즉, 여러 가지 캐리어 전송 모델들은 밀도구배 모델을 기반으로 확산작용과 유체역학, Monto Carlo 전송 모델로 각기 분류할 수 있다. 각각의 모델들은 필수적인 요소에 의존하여 서로 다른 형태로 나타내어 질 수 있다. 이 연구에서는 Sentaurus Device simulation을 통하여 여러 가지 형태의 캐리어 전송 모델의 변화를 시각적으로 관찰할 것이다.

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Effect of Biomechanical Intervention based on Custom Seating System on Activities of Mouse Click for Children with Cerebral Palsy (맞춤형 착석장치를 통한 생체역학적 중재가 뇌성마비 아동의 마우스 클릭 동작에 미치는 영향)

  • Jeong, Dong-Hoon
    • The Journal of Korean Physical Therapy
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    • v.24 no.2
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    • pp.57-65
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    • 2012
  • Purpose: This study was to investigate the effect of biomechanical intervention, based on the custom seating system on the activities of a mouse click for children with cerebral palsy. Methods: Thirteen children with cerebral palsy participated in this study. We compared reaction time and frequency for proper mouse click in the subject's typical position, in addition to an intervention position. The intervention position conformed to the principle and practice of research on promoting the upper-extremity movement and postural control. The intervention position was achieved through an external postural support, which was based on the custom seating system. Results: Reaction time and frequency for proper mouse click were moderately improved in the intervention position, compared with that of the typical position. There was a statistically significant difference between the typical position and that of the intervention position (p<0.05). Conclusion: Results provide evidence of the positive effects of functional seating on the activities of a mouse click for children with cerebral palsy.

제한수역에서 항행선박이 계류 선박에 미치는 영향에 대한 CFD 연구

  • 송성진;정재환;정동호
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.11a
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    • pp.70-71
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    • 2023
  • 본 연구는 항만 내 LNG 벙커링 동시작업 안전성 평가의 일환이다. 본 연구의 목적은 CFD를 활용하여 제한수역에서 항행선박이 계류된 선박에 미치는 영향을 평가하는 것이다. 수치해석은 Star-CCM+를 활용하였으며, 수치 모델 검증을 위해 해석 결과는 공개된 실험 데이터와 비교하였다. 연구 결과로부터 항행선박과 계류선박 간의 상호작용을 평가하는 중요한 정보를 얻을 수 있었으며, 이는 LNG 벙커링의 안전성을 평가하는 데 활용될 수 있다. 향후 연구에는 다양한 시나리오에 대한 평가 및 STS(Ship-to-ship) LNG 벙커링 동시작업 안전성을 평가하기 위한 연구가 계획되어 있다.

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Suggestion of Synthetic Unit Hydrograph Method Considering Hydrodynamic Characteristic on the Basin (유역의 동수역학적 특성을 고려한 합성단위도 기법의 제시)

  • Kim, Joo Cheol;Choi, Yong Joon;Jeong, Dong Kug
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.1B
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    • pp.47-55
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    • 2011
  • This study suggests new synthetic unit hydrograph method considering hydrodynamic characteristic on the basin. The suggested method based on width function GIUH, and the procedure is summarized as follows; 1) Draw up a travel distance distribution map (width function) which is raster of length between from center of individual cells to the outlet by GIS. 2) Calculation of travel time distribution map (rescaled width function) by hydrodynamic parameters and travel distance distribution map. 3) Derivation of IUH and Duration UH from rescaled width function. 4) Comparison of shape of UH between suggested method and existing synthetic unit hydrograph methods. The target basins are selected Ipyeong and Tanbu subwatershed in the Bocheong Basin. The target basins are similar scale (watershed area), but different drainage structure (drainage density et al.). Therefore we anticipate that there are different hydrologic response functions because different hydrodynamic characteristics. As a result of derivation of UH, existing synthetic unit hydrograph methods are similar shape of UHs about Ipyeong and Tanbu watersheds, but the suggested method is different shape of ones. As a result of application to observed data, the peak discharge by suggested method is similar to existing synthetic unit hydrograph methods, but the peak time is well correspondence between those. Henceforth, if the suggested method combines with the rational velocity estimation method, it is useful method for synthetic of UH in ungauged watershed.

The Effects of Scouring on Mechanical Properties and Appearance of Iyocell -NaOH Scouring vs. Enzymatic Scouring - (정련 방법에 의한 리오셀 섬유의 역학적 변화와 3D CAD SYSTEM에 의한 외관분석 -NaOH와 효소처리 중심으로-)

  • Park, Ji-Yang;Kim, Ju-Hea;Jeon, Dong-Won;Park, Young-Hwan
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.9_10 s.157
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    • pp.1485-1493
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    • 2006
  • This study was to investigate the effect of different scouring methods on mechanical properties and appearance of lyocell. Two different scouring methods were adopted for the study; one was the traditional scouring with alkali and the other was enzymatic scouring. Enzymatic scouring was carried with four different enzymes; C1 : Cellusoft L, C2 : Cellusoft UL, D1 : Denimax 992L, D2 : Denimax Acid XCL. The mechanical properties of scoured lyocell were measured using KES-FB. The appearance of scoured samples was analyzed by 3D CAD SYSTEM of i-Designer. While the untreated fabric showed the best linearity because it is stiff, alkali treated samples showed the worst dimensional stability and distorted easily. Enzyme treated samples, especially C1 treated samples showed the best dimensional stability. In addition, enzyme treated samples showed low bending rigidity compared to the alkali treated samples. It means that the enzyme treated samples are more flexible than alkali treated samples. However, the smoothness of the sample's surface treated by either of methods did not show much difference. From the study, it was suggested that the enzymatic scouring for lyocell could help to gain natural silhouette.