• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.4
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• pp.124-131
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• 2003

When a secondary gaseous flow is injected vertically into a supersonic flow through circular nozzle, a complicated structure of flow field is produced around the injection area. The interaction between the two streams produces a strong bow shock wane on the upstream side of the side-jet. The results show that bow shock wave and turbulent boundary layer interaction induces the boundary layer separation in front of the side-jet. This study is to analyze the structure of flow fields and distribution of surface pressure on the flat plate according to total pressure ratio using a supersonic cold-flow system and also to study the control force of affected side-jet. The nozzle of main flow was designed to have Mach 2.88 at the exit. The injector has a sonic nozzle with 4mm diameter at the exit of the side-jet. In experiments, The oil flow visualization using a silicone oil and ink was conducted in order to analyze the structure of flow fields around the side-jet. The flow fields are visualized using the schlieren method. In this study, a computational fluid dynamic solution is also compared with experimental results.

• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.755-766
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• 2003

The surrealism for the revelation of the unconscious realms shares the inner world of mentality with modern fashion display for the visual expression of sensation each other. The analysis of the influence which automatism technique of surrealism exerts on fashion display showed as follows : 1) The automatism technique elevated the dramatic effect of the sales room by scraping the perspective, or the principle of visual arts. 2) It maximized the effect of subject of the display by coinciding surrealism with realism. 3) The technique which distorts the things heralded the strong message to customers by letting them keep away from the fixed idea. 4) Humorous expression of display brought about the effect of sales stimulation by giving astonishment, shock and exaggeration. 5) Expression of surrealism and realism caused customers to feel shock, illusion, fantasy. 6) The automatism technique expressed the high-tech image, and free expression by revealing the diversity of subject. 7) Display hinted from nature satisfied the mental desire of the human beings to be assimilated with nature. The formative characteristic presented the new possibility of combination of display with arts through the avant-garde sensation. Sale's room, or the marketing space was to be sublimated to three dimensional art space, which enhanced the image of sale's room, furthermore meeting the demand of moderner's lifestyle.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.99-99
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• 2003

We studied the effect of Rubus croceacanthus Leveille (RCL) on mast cell-mediated anaphylactic reactions. RCL inhibited compound 48/80-induced systemic anaphylactic shock. When RCL was given at concentrations ranging from 0.01 to 1 mg/$m\ell$, the histamine release from rat peritoneal mast cells induced by compound 48/80 was reduced in a dose-dependent manner. RCL also inhibited passive cutaneous anaphylaxis activated by anti-dinitrophenyl IgE. In addition, RCL inhibited phorbol 12-myristate 13-acetate and A23187-induced tumor necrosis factor-${\alpha}$ secretion from human mast cell line HMC-1 cells. These results indicate that RCL may possess a strong anti-anaphylactic activity.

• Journal of computational fluids engineering
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• v.14 no.1
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• pp.70-77
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• 2009

In this study, time-dependent numerical analysis was carried out to investigate the plasma jet impingement on a flat plate, and a compressible form of two-dimensional inviscid gas dynamics equations were solved using the flux corrected transport algorithm. The mathematical modeling of Joule heating in the polycarbonate capillary bore and the mass ablation from the bore wall was incorporated in the numerical analysis and the series of computation was performed for three cases depending on the distance of the opposing plate from the capillary exit. The computational results reveal that the presence of the opposing plate does not affect the flow conditions inside the capillary when compared to the case of open-air plasma discharge. In the exterior region, the flow structure shows the typical supersonic underexpanded jet which consists of the strong Mach disk in front of the opposing plate and the barrel shock at the side of the jet. It is found that the shock evolution becomes more quasi-steady when the plate distance decreases. Also, the effects of the distance between the capillary bore exit and the opposing plate on the flow conditions along the opposing plate are investigated and the pressure variation on the plate shows more complicated interaction between the plasma discharge and the opposing plate when the location of plate becomes closer to the capillary exit.

• The Journal of the Korean Society for Microbiology
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• v.35 no.2
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• pp.109-115
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• 2000

FtsH is a membrane-bound, ATP-dependent metalloprotease that is involved in a variety of cellular functions including the regulation of responses to heat and stress shock. Previously, we had cloned and sequenced pneumococcal ftsH gene whose deduced amino acid sequence was very similar to those of several gram-positive bacteria and Escherichia coli, except for the N-terminal domain that was responsible for membrane anchoring. In order to better understand the role of Streptococcus pneumoniae FtsH, we expressed pneumococcal ftsH gene in Escherichia coli. When it was expressed from a strong promoter, $P_{tac}$, a considerable amount of the recombinant FtsH was produced, although the prolonged induction resulted in not only accumulation of breakdown products but also ceasing of the further growth of E. coli host. This indicated that the expression of the exogenous ftsH gene was tightly regulated since the excessive FtsH appeared detrimental to bacterial cells. In Western blotting, the pneumococcal FtsH protein, whether native or recombinant, was reactive to anti-E. coli FtsH serum. The observation that FtsH proteins were well conserved throughout the bacterial kingdom and its expression level was fine-tuned suggests an important role for this protein in the stress adaptation which may be related to infecting process by pneumococci.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.1
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• pp.53-62
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• 2003

In this study, nonlinear aeroelastic characteristics of an supersonic missile wing with strong shock interferences are investigated. The missile wing model has a freeplay structural nonlinearity at its pitch axis. To practically consider the effects of freeplay structural nonlinearity, the fictitious mass method is applied to structural vibration analysis based on finite element method. Nonlinear aerodynamic flows with unsteady shock waves are also considered in supersonic flow regions. To solve the nonlinear aeroelastic governing equations including the freeplay effect, a modal-based coupled time-marching technique based on the fictitious mass method is used in the time-domain. Various aeroelastic computations have been performed for the nonlinear wing structure model. Linear and nonlinear aeroelastic analyses have been conducted and compared with each other in supersonic flow regions. Typical nonlinear limit cycle oscillations and phase plots are presented to show the complex vibration phenomena with simultaneous fluid-structure nonlinearities.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.315-324
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• 2012

This paper presents a numerical investigation of the deflagration-to-detonation transition (DDT) of flame acceleration by a shock wave filled with an ethylene/air mixture as the combustible gas, considering geometrical changes by using obstacles and bent tubes. The model used consists of the reactive compressible Navier-Stokes equations and the ghost fluid method (GFM) for complex boundary treatment. Simulations with a variety of bent tubes with obstacles show the generation of hot spots through flame and strong shock-wave interactions, and restrained or accelerated flame propagation due to geometrical effects. In addition, the simulation results show that the DDT occurs with a nearly constant chemical heat-release rate of 20 MJ/($g{\bullet}s$) in our numerical setup. Furthermore, the DDT triggering time can be delayed by the absence of unreacted material together with insufficient pressures and temperatures induced by different flame shapes, although hot spots are formed in the same positions.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.2
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• pp.24-32
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• 2008

A non-reacting experimental study on a normal injection into a Mach 1.92 crossflow which flows over various geometries(flat plate, small cavity, large cavity) was carried out to investigate the effect of the momentum flux ratio(J). The aft ramp of the cavity advances the increase of the penetration height and the strong two-dimensional shock from recompression region mainly affects the shock structure and mixing layer at the downstream flow. As flow runs downward, the transverse penetration height increases with increasing J(J = 0.9, 1.7, 3.4). However, above some critical ratio, jet penetration height growth with increasing J is not appeared in flow-field. Large scale cavity has a good mixing efficiency but it increases the drag loss in the combustor.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.5
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• pp.346-354
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• 2002

The present study is to investigate the propagation characteristics of the impulse waves discharged from the exit of the convergent and divergent pipes. An experiment is carried out using a shock tube with an open end and is compared to the computation of the axisymmetric, compressible, unsteady Euler equations, which are solved by the second-order total variation diminishing (TVD) scheme. For the computational work, several initial compression waves are assumed inside the pipe so that those are the same to the experimental ones of the shock tube. The results show that the peak pressures of the impulse waves discharged from the exit of convergent and divergent pipes decrease with an increase in the wavelength of the initial compression wave. All of the impulse waves have a strong directivity toward the pipe axis, regardless of the exit type of the pipe employed. The impulse waves discharged from the divergent pipe are stronger than those from the straight pipe, while the impulse waves of the convergent pipe are weaker than those from the straight pipe. It is found that the convergent pipe can play a role of a passive control to reduce the peak pressure of the impulse wave. The present computations represent the experimented impulse waves with a good accuracy.

• International Area Studies Review
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• v.20 no.2
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• pp.3-23
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• 2016

In this study, we used actual proof analysis, based on SVAR model according to economy theory, to observe the impact of actual and financial market of Korea, Japan, and China that have adopted quantitative easing export based strategy of growth, an unconventional monetary policy of the U.S. As a result of estimation, it appears that real effective exchange rate rise shock of Korea, Japan, and China against U.S. dollar has a negative influence on current account and index of industrial product, which are real economy. It can be implied that the result is driven from the fact that strong home currency of Korea, Japan, and China decreases price competitiveness of exports, causing negative influence on real economy. The real effective exchange rate shock against U.S. dollar appeared to decrease national bond rate of Korea and Japan, while increasing that of China. In instances of Korea and Japan, it is implied that national bond rate decreases as foreigner investment funds flow in, considering foreign-exchange profit through advanced financial market with high opening extent. On the other hand, because there are strong regulation on opening extent of Chinese financial markets, the influence seems to be greater for domestic policy, rather than a foreign influence. Lastly, Korea showed a more dramatic variable reaction to exchange rate shock compared to Japan or China. It is implied from the result that Korea is relatively more susceptible and fragile in regards of international status of economic size and currency.