• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.189-196
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• 2012

The heavy moderator acts as the ultimate heat-sink in an operating CANDU reactor. HUKINS has been developed to investigate moderator flow patterns. HUKINS consists of a 38.4-mm-thick cylindrical shell with a 0.95 m inner diameter and 88 sus-tubes that produce a total heat of 10 kW. A chemical visualization method was selected to estimate the occurrence of typical moderator flow patterns. Momentum-dominated flow, mixed flow, and buoyancy-dominated flow are detected under conditions of a heat load of 7.7 kW and input mass flow rates of 4, 7, and 11 L/min. The experimental results are similar to the results of a CFD simulation that consisted of approximately 1.9 million grids and was conducted using the k-${\varepsilon}$ turbulence model. Therefore, both the present experiments and simulations using HUKINS, a 1/8-scale model, represent all three important flow patterns expected in the real CANDU6 reference reactor. Thus, it has been demonstrated that HUKINS could be useful in the study of CANDU6 moderator circulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3C
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• pp.251-258
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• 2012

In this paper, we propose a novel method of multi-node frequency synchronization for distributed networks. The proposed method synchronizes carrier frequencies of all nodes in the network and this enables new entry node to synchronize immediately. Moreover, when several groups exist in the network, inter-group synchronization method is proposed. The proposed distributed frequency synchronization method is expected to be very useful for the military operation scenario that new node entry is in a state of flux and group merging and splitting frequently happen.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.611-618
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• 1989

Effects of methionine on cephalosporin C(CPC) production in a fluidized-bed bioreactor were investigated using bioparticles of Cephalosporium acremonium. Since methionine was found to be an important metabolic regulator on the synthesis of cephalosporin C, the effects of its concentration in the cuture broth and feeding mode to the bioreactor were studied. It was observed that the presence of initial methionine was essential for higher cephalosporin C production and there existed an optimal content of methionine. Carbon consumption rate also increased significantly under the presence of methionine. Production of cephalosporin C was most active when methionine was exhausted in the broth; however its additional feeding did not enhance the antibiotic production in the fluidized-bed bioreactor as much as expected. It was therfore considered important to feed an optimal content of methionine at the early operating stage for a higher cephalosporin C production in a fluidized-bed bioreactor. An interesting thing to note was that titre of the antibiotic with reused bioparticles was about 2 times higher in the methionine containing medium than that without methionine. Therefore repeated use of bioparticles, with an optimal content of methionine, was believed to be very useful to enhance to process productivity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.160-166
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• 2018

The worldwide semi-conductor market has been growing for a long time. Manufacturing lines of semi-conductors need to handle several types of toxic gases. In particular, they need to be controlled accurately in real time. This type of toxic gas control system consists of many different kinds of parts, e.g., fittings, valves, tubes, filters, and regulators. These parts obviously need to be manufactured precisely and be corrosion resistant because they have to control high pressure gases for long periods without any leakage. For this, surface machining and hardening technologies of the metal block and metal gasket need to be studied. This type of study depends on various factors, such as geometric shapes, part materials, surface hardening method, and gas pressures. This paper presents strong concerns on a series of simulation processes regarding the differences between the inlet and outlet pressures considering several different fluid velocity, tube diameters, and V-angles. Indeed, this study will very helpful to determine the important design factors as well as precisely manufacture these parts. The EP (Electrolytic Polishing) process was used to obtain cleaner surfaces, and hardness tests were carried out after the EP process.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.53.2-53.2
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• 2005

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.58.2-58.2
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• 2005

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.371-376
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• 2008

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.92-92
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• 2010

• Journal of KSNVE
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• v.6 no.4
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• pp.410-413
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• 1996

초병렬처리는 컴퓨팅의 신기술로서 앞으로 유망한 수단이며 조만간에 보편화 될 전망이다. 이미 유동이나 연소 해석, 비선형 구조해석 등의 분야에서 병렬 프로 그래밍 연구가 활발해지고 있고, 상요 소프트웨어 업체들에서 parting작업을 시작 하였다. 음향해석에 관련된 학자나 연구원들이 지금부터라도 관심을 기울이면 세계 의 수퍼컴퓨팅 신기술 조류에 시작단계에서 동참할 수 있다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2007.11a
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• pp.163-168
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• 2007