• 한국수산과학회지
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• 제35권5호
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• pp.490-496
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• 2002

한국, 미국, 일본지역에 서식하는 연어에서 추출한 genomic DNA를 이용하여 연어의 mtDNA NDI 영역, D-loop 영역, growth hormone, IGF-I, MCH2, histone H3의 염기서열을 분석하여, 최적의 primer를 제작하여 PCR을 실시한 결과, mtDNA NDI 영역은 Ks12, Ks24, As11, As14, Js13, Js15에서 증폭된 DNA를 확인하였으며, D-loop 영역, growth hormone, IGF-I, histone H3, MCH2에서는 모든 시료에서 증폭된 DNA를 확인하였다. DGGE 분석의 결과, mtDNA NDI 영역 (AF133701, 449-880), D-loop 영역 (AF125518, 11-514)과 growth hormone (AFO05927, 181-530)에서는 이형다양성을 확인하였으며, IGF-I (AF063216, 962-1461)과 MCH2 (M27281, 70-593)는 모두 이형다양성이 나타났으나, histone H3 (AF017147, 7-487)는 모두 이형다양성이 관찰되지 않았다. 그리고 real time PCR 관찰 결과는 DGGE의 결과와 유사한 점을 찾을 수 없었지만, real time PCR도 각각의 유전자에 따라 서로 다른 DNA 생성 패턴을 보여 DNA 변이를 쉽게 구별하는데 보조적인 도움이 되었다.

• 한국연소학회지
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• 제17권4호
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• pp.30-37
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• 2012

The flame lengths and NOx emission characteristics of syngas $H_2$/CO turbulent non-premixed jet flames were investigated. The flame length which is the main parameter governs NOx emission was studied for various syngas compositions. The flame length was compared with previous correlation between Froude number and flame height and it shows that they have good agreements. It was confirmed that the turbulent jet flames herein investigated are in the region of buoyancy-momentum transition. NOx emission was reduced with increased Reynolds number and CO contents in syngas fuel and with decreased fuel nozzle diameter which is attributed by decreased flame residence time. Previous EINOx scaling based on flame residence time of $L_f^3/(d_f^2U_f)$ satisfies only the jet flame in momentum-dominated region, not buoyancy-momentum transition region. The simplified flame residence time ($L_f/U_f$) was adopted in modified EINOx scaling. The modified scaling satisfies the jet flames not only in momentum-dominated region but in buoyancy-momentum transition region. The scaling is also satisfied with $H_2$/CO syngas jet flames.

• Journal of Animal Science and Technology
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• 제46권1호
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• pp.1-6
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• 2004

본 연구는 MCIR$^*$3 allele의 돼지에 있어서 유전적 변이를 관찰하기 위하여 수행하였다. 일반적으로 흑모색 바탕에 백색반점이나 백색띠를 갖고 있는 돼지의 MCIR 유전자의 유전자형은 E$^{D2}$로 나타낸다. 우성 백색계통의 E$^P$ 유전자형은 우성 흑모색 계통의 E$^{D2}$ 유전자와 frameshift mutation 관계가 있다. 돼지 MCIR 전체 번역지역을 증폭하기 위하여 oligonucleotide primer률 제작하여 PCR을 수행 하였다. 그 결과 길이가 963${\sim}$966 base pairs인 돼지 MCIR 유전자의 전체번역지역을 포함하는 산물을 얻었다. 이들 번역부위의 염기서열 결정하고 이들을 Clusta1 W 프로그램을 이용하여 정렬한 결과 23번 코돈{nt68)에서 Hampshire와 제주 재래혹돈은 염기 시토신(cytosine)이 3 개 그리고 Birl‘shire의 경우 염기 시토신(cytosine)이 2개 결실되어 있었다. 그 외에 3개의 missense mutations과 하나의 frameshift mutation이 발견되었다.

• Environmental Engineering Research
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• 제21권2호
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• pp.196-202
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• 2016

Membrane bioreactor (MBR) technology has previously been used by water industry to treat high salinity wastewater. In this study, an anoxic-oxic biofilm-membrane bioreactor (AOB-MBR) system has been developed to treat mustard tuber wastewater of 10% salinity (calculated as NaCl). To figure out the effects of operating conditions of the AOB-MBR on membrane fouling rate ($K_V$), response surface methodology was used to evaluate the interaction effect of the three key operational parameters, namely time interval for pump (t), aeration intensity ($U_{Gr}$) and transmembrane pressure (TMP). The optimal condition for lowest membrane fouling rate ($K_V$) was obtained: time interval was 4.0 min, aeration intensity was $14.6 m^3/(m^2{\cdot}h)$ and transmembrane pressure was 19.0 kPa. And under this condition, the treatment efficiency with different influent loads, i.e. 1.0, 1.9 and $3.3kgCODm^{-3}d^{-1}$ was researched. When the reactor influent load was less than $1.9kgCODm^{-3}d^{-1}$, the effluent could meet the third discharge standard of "Integrated Wastewater Discharge Standard". This study suggests that the model fitted by response surface methodology can predict accurately membrane fouling rate within the specified design space. And it is feasible to apply the AOB-MBR in the pickled mustard tuber factory, achieving satisfying effluent quality.

• 한국자기학회지
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• 제27권1호
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• pp.18-22
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• 2017

저 강도 자기장을 이용하여 기존의 6 MV 광자선에 대한 선량 상승보다 향상된 선량 변조 방법을 제안하고 이를 실험적으로 선량 효과를 확인하고자 하였다. 0.5 T (Tesla) 강도를 지니는 두 개의 네오디뮴 영구 자석을 광자선에 수직 방향으로 자기장을 인가하였다. 자석과 자석 간의 거리(MMD)와 자석과 물 표면 간의 거리(MSD)에 따라 자기장을 인가한 경우와 인가하지 않은 경우에서의 선량 상승 영역의 선량 변화를 측정하였다. 자석과 자석 간의 거리가 6 cm이고 자석과 물 표면 간의 거리가 2.5 cm 조건에서 기존 6 MV 광자선의 선량 상승 곡선과 비교하여 $D_{0mm}$, $D_{2mm}$, $D_{5mm}$, $D_{10mm}$ 가 각각 6.8 %, 14.6 %, 6.9 %, 2.1 %의 향상된 선량 효과를 보였다. 본 연구를 통해 피부와 매우 인접한 곳에 위치해 있는 표적 체적을 방사선 치료할 경우, 인체 외부에 바로 자기장을 인가하면서 기존 광자선보다 향상된 선량 상승을 기대할 수 있어 임상 적용 가능성이 높을 것으로 기대된다.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.295-302
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• 2009

The flow in the draft tube cone of Francis turbines operated at partial discharge is a complex hydrodynamic phenomenon where an incoming steady axisymmetric swirling flow evolves into a three-dimensional unsteady flow field with precessing helical vortex (also called vortex rope) and associated pressure fluctuations. The paper addresses the following fundamental question: is it possible to compute the circumferentially averaged flow field induced by the precessing vortex rope by using an axisymmetric turbulent swirling flow model? In other words, instead of averaging the measured or computed 3D velocity and pressure fields we would like to solve directly the circumferentially averaged governing equations. As a result, one could use a 2D axi-symmetric model instead of the full 3D flow simulation, with huge savings in both computing time and resources. In order to answer this question we first compute the axisymmetric turbulent swirling flow using available solvers by introducing a stagnant region model (SRM), essentially enforcing a unidirectional circumferentially averaged meridian flow as suggested by the experimental data. Numerical results obtained with both models are compared against measured axial and circumferential velocity profiles, as well as for the vortex rope location. Although the circumferentially averaged flow field cannot capture the unsteadiness of the 3D flow, it can be reliably used for further stability analysis, as well as for assessing and optimizing various techniques to stabilize the swirling flow. In particular, the methodology presented and validated in this paper is particularly useful in optimizing the blade design in order to reduce the stagnant region extent, thus mitigating the vortex rope and expending the operating range for Francis turbines.

• 한국전산유체공학회지
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• 제21권2호
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• pp.106-111
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• 2016

Waste-to-energy facilities including incinerators are known as an efficient method to reduce wastes. In waste-to-energy facilities, more efficient cooling system is still needed for grates as the energy density of waste increased. For better cooling performance with the water-cooled grates, optimal design of cooling water pathways is highly beneficial. We performed numerical investigation on fluid flow and residence time of cooling water with change of the geometry of the cooling water pathway. With addition of round shaped guide vanes in the water pathway, the maximum residence time of flow is reduced(from 4.3 sec. to 2.4 sec.), but there is no significant difference in pressure drop between inlet and outlet, and average residence time at the outlet. Furthermore the flow stagnation region moves to the outlet, as the position of the round shaped guide vanes is located to the neck point of pathways.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2648-2665
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• 2022

Device-to-device (D2D) multicast has become a promising technology to provide specific services within a small geographical region with a high data rate, low delay and low energy consumption. However, D2D multicast communications are allowed to reuse the same channels with cellular uplinks and result in mutual interference in a cell. In this paper, an intelligent channel assignment algorithm is designed in D2D underlaid cellular networks with the target of maximizing network throughput. We first model the channel assignment problem to be a throughput maximizing problem which is NP-hard. To solve the problem in a feasible way, a novel channel assignment algorithm is proposed. The key idea is to find the appropriate cellular communications and D2D multicast groups to share a channel without causing critical interference, i.e., finding a channel for a D2D multicast group which generates the least interference to network based on current channel assignment status. In order to show the efficacy and effectiveness of our proposed algorithm, a novel search algorithm is proposed to find the near-optimal solution as the baseline for comparisons. Simulation results show that the proposed algorithm improves the network throughput.

• 동력기계공학회지
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• 제13권2호
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• pp.30-35
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• 2009

Numerical Calculations for dimensionless pressure drop (friction factor times Reynolds number) have been obtained for fully developed laminar flow of MPL(Modified Power Law) fluid in isosceles triangle pipes. The solutions are valid for Pseudoplastic fluids over a wide range from Newtonian behavior at low shear rates through transition region to power law behavior at higher shear rates. The analysis identified a dimensionless shear rate parameter which for a given set of operating conditions specifies where in the shear rate range a particular system is operating, i.e., Newtonian, transition or power law region. The numerical calculation data of the dimensionless pressure drop for the Newtonian and power law regions are compared with previously published asymptotic results presenting within 0.16 % in Newtonian region and 2.98 % in power law region.

• ETRI Journal
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• 제31권1호
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• pp.68-70
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• 2009

In this letter, a parametric analysis of the Fresnel-field antenna measurement method is performed for a square aperture. As a result, the optimum number of Fresnel fields for one far-field point is guided as $M_{opt}=N_{opt}=D^2/{\lambda}R+5$, where D is the antenna diameter, ${\lambda}$ is the wavelength, and R is the distance between the source antenna and the antenna under test. For the aperture size 5 ${\leq}$ $L_x/{\lambda}$ ${\leq}$ 20, the tolerable distances for gain errors of 0.5 dB and 0.2 dB can be guided as $R_{0.5\;dB}$ ${\approx}$ $1.2Lx/{\lambda}$ and $R_{0.2\;dB}$ ${\approx}$ $2.0L_x/{\lambda}$, where $L_x$ is the lateral length of the square aperture. The tolerable distances for 20 ${\leq}$ $L_x/{\lambda}$ ${\leq}$ 200 are also proposed. This measurement guideline can be fully utilized when performing the Fresnel-field antenna measurement method.