• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.584-587
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• 2000

The invasion genes from Salmonella typhimurium were identified by the construction of a cosmid library and subcloning genes into a plasmid vector, pGEM-7Z. The 4.65 kb fragment of the invasion-conferring genomic region of the subclone, pSV6235 was sequenced in both direction. The three open reading frames, which were located at downstream of a promoter region, were designated as sir (Salmonella invasion region)A coding for the 36 amino acids, sirB coding for the 132 amino acids and sirC for the 82 amino acids, respectively. Interesingly, the genomic region of pSV6235 was highly homologous to Yersinia enterocolitica genomic DNA for a high pathogenicity island and Salmonella enteritidis insertion element IS1351 and IS200 DNA. These results show that there could be a significant relationship between S. typhimurium, Y. enterocolitica and S. enteritidis with respect to horizontal evolution process and acquisition of virulence determinants by means of transposon, plasmid or bacteriophage.

• Journal of ILASS-Korea
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• v.1 no.1
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• pp.55-62
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• 1996

In a fuel injection engine, atomization of liquid fuel and mixture formation process has influenced(or affected) directly on the engine performance and pollutant emission. In this study, the characteristics of fuel spray and the behaviors of secondary atomization developed at the downstream of the valves were investigated using an image processing method. Solid and perforated valves are chosen in order to evaluate the valve performance in terns of air flow rate, valve opening angle and valve shape. Experimental results clearly indicate that the spray atomization quality can be improved by increasing the perforated rat io and the blockage rat io in the perforated valve, the characteristics of spray atomization is improved by using the perforated valve with high perforated rat io and blockage ratio.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1543-1551
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• 2003

The present study investigates turbulent flows subject to strong wall injection in a channel through a Direct Numerical Simulation technique. These flows are pertinent to internal flows inside the hybrid rocket motors. A simplified model problem where a regression process at the wall is idealized by the wall blowing has been studied to gain a better understanding of how the near-wall turbulent structures are modified. As the strength of wall blowing increases, the turbulence intensities and Reynolds shear stress increase rapidly and this is thought to result from the shear instability induced by the injected flows at the wall. Also, turbulent viscosity grows rapidly as the flow moves downstream. Thus, the effect of wall-blowing modifies the state of turbulence significantly and more sophisticated turbulence modeling would be required to predict this type of flows accurately.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.103-103
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• 2003

대기나 물에 용해된 여러 가지 유해한 유기물을 분해하기 위한 방안으로서 다양한 광촉매 재료를 이용하려는 시도가 진행되고 있다. 하지만 광촉매 반응은, 현탁액 내에서 submicrometer 크기를 갖는 반도체재료에서 발생하므로 처리된 폐수로부터 촉매를 제거해야 하는 정제공정 (downstream process)이 필요하며, 이는 경제적인 측면에서 큰 경비를 요구하게 된다. 이를 해결 하기 위하여, 가장 우수한 광촉매 재료로 평가받는 TiO$_2$를 glass beads, sands, silica gel등의 물질에 고정시키거나, TiO$_2$를 자성 입자에 코팅시킨 형태인, 자성 광촉매입자를 응용하려는 연구가 최근 활발하게 진행되고 있다. 따라서 본 연구에서는 광촉매의 고정화와 재활용 효율을 향상시키기 위하여 TiO$_2$ 나노입자를 y-Fe$_2$O$_3$ 나노입자의 표면에 코팅하여 나노입자의 큰 비표면적을 활용하고 미세구조를 제어하여 입자간의 고정특성과 자기적 특성의 제어기술을 확립하고자 하였다.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.245-248
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• 2005

SCRamjet is the key technology for hypersonic flight over mach number 6. It is characterized by very short residence time in combustor because its internal flow is supersonic. In this short time, the whole process of combustion must be done. Especially numerical study of combustor is important because air-fuel mixing rate influences the performance of combustor. Various methods of air-fuel mixing enhancement are proposed. Among these, cavity injection method is selected to study in this paper. The numerical study is conducted with the variation of the cavity length at the fixed height of unit and jet injection on the downstream of cavity.

• Journal of Korea Technology Innovation Society
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• v.5 no.2
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• pp.167-188
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• 2002

Summary: This paper analyzes Indian software industry in the perspective of innovation cluster. The research shows that the software industry has been following an upstream clustering process, where the major value activity is expanding from low value product/services to high value product/services. The growth of software industry could be successful because there was appropriate initial condition of Bangalore, such as the availability of high qualified human resources, excellent research institutes, small high-tech companies. The role of government was helpful for the late growth of software industry but not a critical factor for the initial development of the S/W cluster. It is suggested that government should consider the initial condition of a concerned location critically to implement a cluster-type innovation policy.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.77-79
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• 1996

근래들어 생물기술이 급속히 발전함에 따라 생물반응을 통해 다양한 생물제품들의 생산이 이루어지고 있다. 생물반응에 의한 생물제품들의 생산량은 극단적으로는 기질 1g당 10$^{-8}$g 정도로서 극히 낮아 이를 상업제품이 요구하는 순도(95 %이상)로 까지 정제하기 위해서는 여러 단계를 거치는 복잡하고 지루한 분리.정제 과정이 필요하며, 이 분리.정제의 후류공정(downstream process)비용이 생물제품 생산비의 상당부분을 점유케 되어 생물공정의 경제성을 낮게 한다. 따라서 생물공정을 이용한 생물제품 생산이 산업적으로 경제성을 갖기 위해서는 생물제품을 보다 효율적.경제적으로 분리.정제할 수 있는 후류공정의 확립이 요구된다. 본 연구에서는 산업적 규모로 생산되는 생물제품들을 효율적으로 분리.정제하는데 응용 가능한 방법의 하나로서 관심의 대상이 되고 있는 책체 크로마트그래피 기법을 연구의 대상으로 하였다.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.323-330
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• 2011

Large number of part design such as for aircraft and automotive development is preceded by functional or sectional design groups for efficiency. With the assembly development of large number of parts, interferences and gaps can be found when the parts and sub-assemblies by those design groups are to be assembled. When rainwater come into the space among parts and is not be drained sufficiently, rainwater within the structure can backflow to gaps or unexpected outlets, which may cause severe problems of part corrosion and electric shock. This research has developed a method and a program to simulate backflow of rainwater within space among parts, which can find unexpected outlets and gaps as in real situation. The developed program can not only simulate up and downstream of liquid, but also the flow with multiple channels of division and joining. The developed method can also be applied to aircraft and ship design process.

• Korean Journal of Construction Engineering and Management
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• v.2 no.4 s.8
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• pp.144-156
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• 2001

This study aims at improving the limitations of current construction processes. Previous solutions to improve construction processes have been focused on the improvement of local processes. This paper proposes a method to improve global effectiveness of construction processes through ascertainment of communication among the process participants. This paper provides two case studies: Deck plate installation processes and Duct installation processes. The case study illustrates a way to improve global effectiveness by incorporating downstream participants such as specialty contractors in upstream construction processes such as design and planning.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.1-1
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• 2010

With the power of supercomputers increasing exponentially, there is an insatiable need for more advanced multi-disciplinary aerospace CFD simulations. A particular current interest is the 3D viscous turbulent simulation of the highly nonlinear aspects of aero-icing. The applications of CFD in that field are literally light-years behind aerodynamics, with a significant number of users still mired in correlations, or 2D, inviscid, incompressible, and, yes, Panel Methods simulations! Thus, the disparity of tools between aerodynamics and icing departments within an organization leads to a disconnect that makes ice protection a downstream isolated process that is not an integral part of the aerodynamic behavior of an aerospace system (aircraft, rotorcraft, jet engine, UAV, etc.). While 3D RANS has been recently introduced, it is still considered computationally too demanding for industry when wide parametric studies for certification are required. In addition, not unlike the situation in aerodynamics say 20 years ago, naysayers are at every corner claiming that CFD is not reliable and is of limited use.