• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.106-116
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• 2009

In order to investigate change of vortex structures and its evolving proceses, two dimensional LDV system was used for measurement of velocity vectors of tip vortex, and PIV system was also used for visualizations of tip vortex array for two bladed rotor, respectively. Experiments provided vortex locations, tangential and axial velocity components of tip vortex at six wake ages of 9.5, 10.5, 60.5, 99.5, 129.5, 169.5 and corresponded six wake ages shifted with 180 degrees per each. It was resulted that tip vortices generated by the first blade satisfy Landgrebe's model for their vortex locations even after they were accelerated by the second blade in downstream. Tangential velocity components of tip vortices follow Vatistas' n=2 model on both inside and outside regions of rotor slipstream without loss of vortex circulation. Axial velocity profiles revealed that there were small but significant perturbations just outside the primary vortex core which implies the second blade affects the wake substantially. It was also found that tip paths of each blade were not willing to be coincided intrinsically.

• Journal of ILASS-Korea
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• v.16 no.4
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• pp.201-209
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• 2011

Optimum engine performance is obtained when the spray characteristics is well matched to the geometry of a combustion chamber. Among many parameters governing the combustion performance in internal combustion engine, fuel supply characteristics and atomization are important performance factors. Therefore, spray characteristics of high pressure multi-hole injector has been studied experimentally. An experimental test system has been made to operate high pressure injection system and to visualize spray behavior. Spray visualization has been performed to analyze spray formation, spray cone angle, bent angle and penetration length. Spray interaction with piston has been analyzed with various injector installation angle, injection pressure and ambient pressure. Test results show that penetration length is greatly influenced by the injection pressure. Penetration length is decreased as ambient pressure increased. Spray cone angle is increased as injection pressure and ambient pressure increased. However, bent angle is not influenced by the change of injection pressure and ambient pressure. Spray cone angle distribution map is plotted using the experimental data. Fuel movement around the spark-plug has been enforced as increasing injector installation angle.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.227-232
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• 2008

Since 2000, there have been many changes in the residential types, such as an intelligent apartment which integrates both resting space and production space with comfort able, pleasant and safe environments based on internet systems. As the result of the rapid decrease in the birth rate and the prolonged lifespan around the world, it is expected that we will enter into an aging society by 2026. With such the expected change in the living patterns, many issues concerning the increased number of the elderly people have emerged as major social problems such as changes of family formation, its function and values, responsibility of caring for the aged, health and medical care, habitation policies and so on, and it is required to reconsider the social awareness on the living qualities of each old person. However, we have not yet satisfied such requirements with appropriate policies for the improvement of the living environment for them. It is considered, therefore, that we need to develop a new tool that, according to our goals, can give us a broad understanding on several considerations in designing the future homes for the elder people, making it possible to check the process changed by residents' needs in real time and apply it immediately to the space. As we have seen, it is required that spatial design process and design methodology should be considered in designing the homes for the aged for the pre-occupancy design evaluation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2423-2430
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• 1994

Several factors of the efficient combustion process are shape of combustion chamber, position of spark plug, turbulence flow and so on. the shape of combustion chamber and position of spark plug are constrained to geometrically, and then it could not make a change the shape easily. But the turlence flow in combustion chamber have a great influence on combustion phenomena, and which is much easier to control relatively. And since characteristics of turbulence flow would be very important to the stability of combustion and performances, This study is also essential to future engine-low emission and lean burn engine. This paper shows that the visualization of the turbulence flow of single cylinder engine by using 2way, $45^{\circ}$ inclined and 2 channel hot wire probe through the park plug hole. We also study the characteristics of turbulence flow by means of ensemble averaged mean velocity, turvulence intensity and integral length scale.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.211-216
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• 2001

Flow motion and variation of thermal field around a bubble which attached at the upper cooled solid wall in a $B\dot{e}nard$ convection flow is studied experimentally using thermo-sensitive liquid-crystal tracers and image processing for flow visualization and analysis. The air is injected gradually by $0.1m\ell$ to make the bubble. As the growing of the bubble in a $B\dot{e}nard$ convection flow, the variation of temperature field and surface tension along the bubble, which in turn cause to change the thermal field patterns and the flow direction and patterns. 6 cells flow pattern is transformed into diverse flow pattern. At the large size of a bubble, it's only conduction mechanism under the region of the bubble because of low Ra number 1137, but the convection flow both sides of the bubble leads to another convection flow in the bubble influence area which has been remained stable stagnation.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.111-114
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• 2004

Molecular imaging provides a visualization of normal as well as abnormal cellular processes at a molecular or genetic level rather than at a anatomical level. Conventional medical imaging methods utilize the imaging signals produced by nonspecific physico-chemical interaction. However, molecular imaging methods utilize the imaging signals derived from specific cellular or molecular events. Because molecular and genetic changes precede anatomical change in the course of disease development, molecular imaging can detect early events in disease progression. in the near future, through molecular imaging we can understand basic mechanisms of disease, and diagnose earlier and, subsequently, treat earlier intractable diseases such as cancer, neuro-degenerative diseases, and immunologic disorders. In beginning period, nuclear medicine started as a molecular imaging, and has had a leading role in the field of molecular imaging. But recently molecular imaging has been rapidly developed. Besides nuclear imaging, molecular imaging methods such as optical imaging, magnetic resonance imaging are emerging. Each imaging modalities have their advantages and weaknesses. The opportunities from molecular imaging look bright. We should try nuclear medicine continues to have a leading role in molecular imaging.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.979-983
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• 2010

In case a set of railway vehicles moves on a rail track, the end of each car in which a coupler is installed produces a complex movement depending on the displacement of a rail track, bogie and a coupler. Especially, the movement of an end of cars is hugely affected by a radius of gyration and gradient of a rail track, vertical and lateral movement of bogie, and compression of coupler. In this thesis, I present a simulation technic for easy input and change of displacement of a rail track, bogie and a coupler as well as visualization of movement of the end of cars on a rail track using CATIA V5, CAD software.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2000.05a
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• pp.76-86
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• 2000

Conventional atom model must be criticized on the following four points. (1) Natural motions between positive and negative entities are not circular motions but linear going and returning ones, for examples sexual motion, tidal motion, day and night etc. (2) Potential energy generation was neglected when electron changes its orbit from outer one to inner one. The hv is the kinetic energy of the photo-electron. The total energy difference between orbits comprises kinetic and potential energies. (3) The structure of the space must be taken into consideration because the properties of the electron do not change during the transition from outer orbit to inner one even though it produces photon. (4) Total energy conservation law applies to the energy flow between mind and matter because we daily experiences a interconnection between mind and body. $\prod$-rays come out from the crystallizing $\pi$-bondings when they vibrate or deform. Gaston Naessens(1950) invented a microscope, which can visualize the $\pi$-rays in blood. Unordinarily agglomerated spores of $\pi$-rays may provoke poor immunity and bad illness. The agglomerated spores of $\pi$-rays can make closed type $\pi$-bondings in the case of carbohydrates and esters but proteins build open type $\pi$-bondings because the peptide bonds are planar, which principle produces a life.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.182-190
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• 2018

The objective of this work is to evaluate the effect of polyamidoamine (PAMAM) dendrimers on electroosmotic flow (EOF) through skin. The effect of size and concentration of dendrimer was studied, using generation 1, 4 and 7 dendrimer (G1, G4 and G7, respectively). As a marker molecule for the direction and magnitude of EOF, a neutral molecule, acetoaminophen (AAP) was used. The visualization of dendrimer permeation into the current conducting pore (CCP) of skin was made using G4-fluorescein isothiocyanate (FITC) conjugate and confocal microscopy. Without dendrimer, anodal flux of AAP was much higher than cathodal or passive flux. When G1 dendrimer was added, anodal flux decreased, presumably due to the decrease in EOF by the association of G1 dendrimer with net negative charge in CCP. As the generation increased, larger decrease in anodal flux was observed, and the direction of EOF was reversed. Small amount of methanol used for the preparation of dendrimer solution also contributed to the decrease in anodal flux of AAP. Cross-sectional view perpendicular to the skin surface by confocal laser scanning microscope (CLSM) study showed that G4 dendrimer-FITC conjugate (G4-FITC) can penetrate into the viable epidermis and dermis under anodal current. The permeation route seemed to be localized on hair follicle region. These results suggest that PAMAM dendrimers can permeate into CCP and change the magnitude and direction of EOF. Overall, we obtained a better understanding on the mechanistic insights into the electroosmosis phenomena and its role on flux during iontophoresis.

• Journal for History of Mathematics
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• v.21 no.4
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• pp.105-126
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• 2008

This article summarizes the historical changes of the secondary school geometry to give insights into the new direction of geometry education for the 21th century. Geometry has been considered as an essential subject in high school since mid-nineteen century in accordance with the social changes. Since the development of computer softwares such as CAD effects on the role of geometry in work and professional societies, the knowledge and skills the contemporary world require to school geometry have being changed. More focus on applications and modeling aspects, expansion of reasoning and problem solving, emphasis on design-related elements are features of the school geometry for the new century.