• Journal of Microbiology and Biotechnology
• /
• 제11권5호
• /
• pp.853-857
• /
• 2001

The effect of silkworm hemolymph on the inhibition of baculovirus-induced insect cell apoptosis was quantitatively investigated using a flow cytometric analysis. Spodoptera frugiperda (Sf9) cell and Autographa californica nuclear polyhedrous virus (AcNPV) were used as a model for insect cell and baculovirus in this study, respectively. Compared with a mammalian cell cycle, the fraction of G1 cells was relatively small in the Sf9 cell cycle. Silkworm hemolymph did not affect the Sf9 cell-cycle distribution before the baculovirus infection. However, the fraction of cells which are not in the sub-G1 phase remained at a high level for 3 days after the infection in the medium without silkworm hemolymph, while it remained at a high level for 7 days after the infection in the medium supplemented with silkworm hemolymph. The fractions of apoptotic cells in the sub-G1 phase were $4.7\%$, and 4 days after infection, $22.7\%$, in the media with and without silkworm hemolymph, respectively.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.768-772
• /
• 2009

This paper proposes a method for measurement three-dimensional trajectories of bubbles generated around a swimmer's arms from stereo high-speed camera videos. This method is based on two techniques: two-dimensional trajectory estimation in single-camera images and trajectory pair matching in stereo-camera images. The two-dimensional trajectory is estimated by block matching using similarity of bubble shape and probability of bubble displacement. The trajectory matching is achieved by a consistensy test using epipolar constraint in multiple frames. The experimental results in two-dimensional trajectory estimation showed the estimation accuracy of 47% solely by the general optical flow estimation, whereas 71% taking the bubble displacement into consideration. This concludes bubble displacement is an efficient aspect in this estimation. In three-dimensional trajectory estimation, bubbles were visually captured moving along the flow generated by an arm; which means an efficient material for swimmers to swim faster.

• 아태비즈니스연구
• /
• 제2권1호
• /
• pp.49-73
• /
• 2011

With the market evaluation of economic globalization exchanges between different cultures, cultural trade has been developing at an accelerated speed, and also playing an important role in East Asian intra-regional trade. In this research the author used gravity trade model to explain the causal relationship between dependent variable trade flows and several independent variables applying with five categories cultural goods which classified in HS codes. Firstly for cultural heritage trade flow, the results indicated that economic masses of bilateral countries have no significant influences on it; GDP per capita of host country and adjacency factor with partner country have significant negative influences on it; Internet coverage ratio has improved cultural heritages exchanges in East Asian regions. Secondly for printed matter cultural goods trade flow, the distance factor has significant negative influence but common language has significant positive influence on it. Thirdly for recorded media cultural goods, only economic masses and GDP per capita of bilateral countries can improved their trade flows. Fourthly for visual arts cultural products trade flows, almost all variables we tested have significant influences on it. Fifthly for cinema photography cultural goods trade flow, the influenced factor are same with cultural heritage products except they have strong positive interaction relationship with economic masses and common language. At last, the paper figured out some important and potential sectors for cultural goods trade in East Asia and gave some suggestions to government and cultural goods product enterprises.

• Korea-Australia Rheology Journal
• /
• 제21권3호
• /
• pp.193-200
• /
• 2009

We present a direct simulation technique for two-dimensional mold-filling simulations of fluids filled with a large number of circular disk-like rigid particles. It is a direct simulation in that the hydrodynamic interaction between particles and fluid is fully considered. We employ a pseudo-concentration method for the evolution of the flow front and the DLM (distributed Lagrangian multipliers)-like fictitious domain method for the implicit treatment of the hydrodynamic interaction. Both methods allow the use of a fixed regular discretization during the entire computation. The discontinuous Galerkin method has been used to solve the concentration evolution equation and the rigid-ring description has been introduced for freely suspended particles. A buffer zone, the gate region of a finite area subject to the uniform velocity profile, has been introduced to put discrete particles into the computational domain avoiding any artificial discontinuity. From example problems of 450 particles, we investigated the particle motion and effects of particles on the flow for both Newtonian and shear-thinning fluid media. We report the prolonged particle movement toward the wall in case of a shear-thinning fluid, which has been interpreted with the shear rate distribution.

• 지질공학
• /
• 제5권2호
• /
• pp.201-213
• /
• 1995

열극암반(Fractured rockmass)의 지하수유동해석을 위해서는 열극현상에 대한 전반적인 이해를 필요로 한다. 열극현상과 관련된 분야는 열극(Fracture)의 생성과 역학이론, 전파, 종식, 분포체계와 구조 및 열극체계 모델링등 다양한 분야가 이에 속한다. 그러나 이러한 분야의 연구는 일부 분야를 제외하고 외국에서도 그 역사가 깊지 못하며, 우리나라의 경우 근래에 일부 학계와 업계에서 관심을 보이고 있을 뿐이다.산업사회의 발달과 함께 다양한 목적으로 지하공간의 이용을 필요로 하게 되었고, 지하공동의 성능평가에 대한 적용방법 또한 복잡하고 다양한 접근방법을 요구하고 있다. 열극현상에 대한 정확한 이해가 지질학과 같은 어느 한 분야의 지식만으로 접근할 수가 없으므로, 열극의 정확한 분포 특성과 열극생선과정의 이론을 근간으로 열극체계 및 유동해석모델의 적절한 연관성을 도출하도록 조화를 이루므로써 신뢰성 높은 성능평가의 목표를 달성할 수 있을 것으로 기대된다.

• 정보저장시스템학회:학술대회논문집
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.248-253
• /
• 2005

The recording density of a hard disk drive is increasing so rapidly that the storage capacity of a commercial HDD in PC reaches several hundred giga bytes recently. Many technologies related to the HDD, such as servo, media, actuator dynamics, thermo and fluid dynamics, etc. must be developed together to realize high recording density. Especially, researches in the airflow inside the HDD cavity become important as the rotational speed of a disk increases. Typical problem due to the airflow is the vibration of an actuator as the airflow collides with an I-block, suspensions and sliders, that is, FIV(Flow Induced Vibration). This problem is one of the significant sources of increasing TMR so that it must be resolved. In this research, a disk damper shape has been modified to minimize the effects of airflow on the actuator. Modified disk dampers which change flow field inside HDD cavity show good effects not only on the disk (tufter but also on the vibration of an actuator. Vibrations of E- block and slider have been measured with LDV and the airflow field inside the HDD cavity has been analyzed using a commercial package to verify these effects.

• 상하수도학회지
• /
• 제18권2호
• /
• pp.181-187
• /
• 2004

The purpose of this study is to investigate the biofilm reactors capable of doing high efficiency treatment. Vertical fluidized bed biofilm reactor(VFBBR) and spiral fluidized bed biofilm reactor(SFBBR) was used for their performence in biodegradation of artificial sewage. The factors influencing the efficiency of those reactors were compared with difference of physical condition. They had same size but different structure to gain access of its unique characteristics. When recycle solution with flow rate of 22 mL/min and artificial sewage with flow rate of 2~10 mL/min were fed into two reactors in aerobic state, the average $COD_{cr}$, removal rate for biodegradation of SFBBR was greater than VFBBR. After reactor feed sewage was constantly maintained as flow rate of 4 mL/min and the recycle solution were changed to 10~32 mL/min respectively, the average $COD_{cr}$ removal rate of artificial sewage in SFBBR was greater than VFBBR. In this experiment for addition of support media into two reactors SFBBR was 4.1% excellent than VFBBR. Above all, SFBBR excelled VFBBR in boidegradation of organic matter in sewage.

• 한국유체기계학회 논문집
• /
• 제15권5호
• /
• pp.11-19
• /
• 2012

The main function of fuel cell manifold is to render reactants distribution as uniform as possible into a fuel cell stack. The purpose of this study is to numerically investigate the effects of stack manifold design on reactants distribution within a fuel cell stack. Four manifold designs with different manifold entrance shapes (expansion or diffuser) and different values of the extra width between the cell outer channel and manifold side wall are considered and applied to the fuel cell stack consisting of 50 cells. Since the fuel cell stack geometry involves several millions of grid points for numerical calculations, a parallel computing methodology is employed to substantially reduce the computational time and overcome the memory requirement. The numerical simulations are carried out and calculated results clearly demonstrate that both the manifold entrance shape and extra width have a substantial influence on manifold performance, controlling the degree of flow separation and entrance length for fully developed flow in the manifold channel. Finally, we suggest the optimum design of fuel cell manifold based on the simulation results.

• 대한기계학회논문집B
• /
• 제32권9호
• /
• pp.683-694
• /
• 2008

The performance and durability of Polymer Electrolyte Fuel Cells (PEFCs) are strongly influenced by the uniformity of current density, temperature, species distributions inside a cell In order to obtain uniform distributions in them, the optimal design of flowfield must be a key factor. In this paper, the numerical study of land/channel flowfield optimizations is performed, using a multi-dimensional, multi-phase, non-isothermal PEFC model. Numerical simulations reveal more uniform current density and HFR(High Frequency Resistance) distributions and thus better PEFC performance with narrower land/channel width where the less severe oxygen depletion effect near the land region and more uniform contact resistance variation along the in-plane direction are achieved. The present study elucidates detailed effects of land/channel width and assist in identifying optimal flow-field design strategies for the operation of PEFCs.

• Elastomers and Composites
• /
• 제37권1호
• /
• pp.49-56
• /
• 2002

UV 조사시간과 오존유량을 변화시키면서 폴리프로필렌을 UV/오존 산화하였으며 이의 표면특성을 접촉각과 XPS를 이용하여 살펴보았다. 산화된 표면의 노화거동을 공기, 물, 에틸렌 글리콜 하에서 살펴보았으며, 또한 lap shear 실험을 통하여 접착력을 관찰하였다. 극성표면 에너지와 접착력은 UV/오존 처리시간과 오존유량이 증가함에 따라 증가함을 알 수 있었다. 물에서 노화실험을 한 경우 극성표면 에너지의 변화가 없었으나, 공기 하에서 실시한 경우 2-3일 이내에 급격히 감소하여 처리하지 않은 폴리프로필렌의 값에 근접하였다.