• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.654-660
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• 1991

Natural convection heat transfer in a horizontal annulus from an inner tube with two vertical fins has been studied for the effects of dimensionless fin length and Rayleigh number. The maximum local Nusselt number of inner tube was obtained at .theta. = 145.deg. and that of outer cylinder at .theta. = 0.deg. for the case of $l_{F}$=0.3 Local Nusselt number distributions for the lower fins show higher values than that of the upper fins. The mean Nusselt number of inner tube was increased with the values of dimensionless fin length. The mean Nusselt number can be represented in an exponential function of Grashof number at various fin lengths. As compared with experimental and numerical results, isotherms and local Nusselt number show good agreement.t.

• Journal of the Korean institute of surface engineering
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• v.51 no.1
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• pp.27-33
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• 2018

In the present work, we demonstrate the feasibility to form large inner diameter $TiO_2$ nanotubes by anodization of Ti in a HF/ethylene glycol electrolyte. In order to achieve the large inner diameter $TiO_2$ nanotubes, optimization of the anodization condition is required. We discover the key factors in the formation of large inner diameter $TiO_2$ nanotubes are concentration of water in the electrolyte, anodization temperatures, and high-applied potential. Under optimum conditions, the inner diameters of $TiO_2$ nanotubes are 379 nm. The results are approximately 3 folders larger than the general case.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.18 no.2
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• pp.93-98
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• 2005

Vertigo occurs when there is conflict between the signals sent to the brain by various balance- and position-sensing systems of the body. Injury to or diseases of the inner ear can send false signals to the brain indicating that the balance mechanism of the inner ear (labyrinth) detects motion. Inner ear disorders, such as benign paroxysmal positional vertigo (BPPV), Meniere's disease, vestibular neuronitis, or labyrinthitis. Vestibular neuronitis is an inflammation of the vestibular nerve, which is located in your inner ear. In this case, She has vertigo occured suddenly and continued even when the person lies completely still. It may be accompanied by nausea and vomiting. She has taken herbal medication and treated by acupunture. Her symptoms become disappeared after 3 days and All most symptoms were disappeard. In conclusion, It is required to classify vestibulopathy into vestibular neuronitis or labyrinthitis. In this case we diagnosed her case as vestibular neuronitis. Her symptoms of vestibulopathy recovered fast by Korean traditional medical therapy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.668-674
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• 2001

An experimental study was performed for two types of co-axial cylindrical shell structures in order to establish the relationship between in-air dynamic characteristics and in-water ones and to observe hydrodynamic mass effects on their mode shapes when submerged. The outer cylinders are prepared with two kinds to get more insights on the fluid-structure interaction phenomena: one is flexible, which means that the outer cylinder has almost same stiffness as the inner one, and the other is a rigid one whose stiffness is more than ten times of the inner one's(it might be regarded as the scaled-down model of the reactor internals). The finite element. analyses were also implemented to support the experimental results. The results show that the natural frequencies of a co-axial cylindrical shell structure in water are remarkably lower than those in air due to the fluid mass effects. In case of the flexible-to-flexible cylinders, there exist in-phase and out-of-phase mode shapes and they are affected by the annular gap between the. co-axial cylinders. For the in-phase mode the in-water natural frequency decreases exponentially as the gap increases, while it slightly increases in case of the out-of-phase mode due to the squeezing effect of the gap fluid. In the flexible-to-rigid case, the normalized natural frequency(in-water frequency/in-air one) of the inner cylinder(core barrel model) ranges between in-phase and out-of-phase mode frequencies of the flexible-to-flexible co-axial cylindrical structure having identical dimensions. Also the normalized natural frequency of the inner cylinder of the flexible-to-rigid one moves from near of the in-phase mode frequency into the out-of-phase mode value of the flexible-to-flexible case as circumferential mode number(n) increases.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.59-67
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• 2011

This paper is focused on the effect of indoor temperature rise according to the use of windows and blinds in double skin facade in summer. For the experiment, we set up the mock-up of double skin facede and measuring temperature and solar radiation. Total 7 cases were used for measuring solar transmittance and indoor temperature rise. When the venetian blind was not installed, solar transmittance was 44.5%, and solar transmittance for the case that installed the venetian blind (angle 0) was 22.5%. Cases that opened inner and outdoor windows for ventilation showed lower indoor temperature rise than cases with closed windows. In addition, Case 5 (opened inner and outdoor windows with the venetian blind (angle 0) to reduce solar transmittance) indicated lower indoor temperature rise than Case 3(opened inner and outdoor windows). Consequently, Case 5 which uses inner and outdoor window for ventilation and venetian blind to reduce solar transmittance is the most effective way to reduce indoor temperature rise among all cases tested in this research.

• Ocean Systems Engineering
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• v.2 no.4
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• pp.297-314
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• 2012

Power-take-off through inner dynamic system inside a floating buoy is suggested. The power take-off system is characterized by mass, stiffness, and damping and generates power through the relative heave motion between the buoy and inner mass (magnet or amateur). A systematic hydrodynamic theory is developed for the suggested WEC and the developed theory is illustrated by a case study. A vertical truncated cylinder is selected as a buoy and the optimal condition of the inner dynamic system for maximum PTO (power take off) through double resonance for the given wave condition is systematically investigated. Through the case study, it is seen that the maximum power can actually be obtained at the optimal spring and damper condition, as predicted by the developed WEC theory. However, the band-width of high performance region is not necessarily the greatest at the optimal (maximum-power-take-off) condition, so it has to be taken into consideration in the actual design of the WEC.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.89-95
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• 2013

In resent years, Offshore Wind Farm (OWF) is being actively developed. Typically, OWF has a better wind resource than onshore one, but also have a very high investment cost and maintenance cost. Furthermore, due to a difficulty of geographical access, OWF can be affected by the failure for a longer time. As the result, OWF has a higher loss cost. Therefore, a reliability evaluation should be performed more carefully at OWF planning stage. In this paper, a methodology for the reliability evaluation on inner grid is suggested. Inner grid connects wind turbines via submarine cables and transfers power to offshore substation. According to location of the faulted cable under layouts of inner grid, the transfer ability of inner grid is influenced. In order to indicate the transfer ability of inner grid, several indices are introduced such as PNDR, EEND and EENDC. To demonstrate the methodology described in this paper, diversity case studies were performed.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.46-54
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• 2014

The hollow design of a railway axle is one of the most effective methods to reduce the weight of an axle. However, the conventional hollow axle has the limitation of a lightweight design because it has the same bore diameter along the axial position. The new type of railway axle, the tapered inner surface railway axle, has a different inner diameter between the journal bearing seat and wheel seat. This design method is one way to increase the weight reduction possibility. The purpose of the present study is to establish and evaluate the design of the tapered inner surface railway axle. The case study and Finite Element Method(FEM) are applied to evaluate the strength of the lightweight railway axle according to the European Norm(EN 13103). Finally, the best design case for reducing the weight of the axle is drawn from the results of the case study.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.934-940
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• 2011

A novel reconfigurable beam steering antenna using double loops is proposed. The double loop antenna has a superposed beam which is produced by combining the in-phase beam in the inner loop with the out-of-phase beam in the outer loop. Also, the doble loop antenna uses two artificial switches to connect between inner loop and outer loop, and has the beam directions of three separate cases(Case 1, Case 2, Case 3) by changing ON/OFF states of switches. The operation frequency of the antenna is 14.5 GHz, and three maximum beam directions of the antenna are ${\phi}_{max}=0^{\circ}$, ${\theta}_{max}=0^{\circ}$(Case 1), ${\phi}_{max}=230^{\circ}$, ${\theta}_{max}=40^{\circ}$(Case 2) and ${\phi}_{max}=130^{\circ}$, ${\theta}_{max}=40^{\circ}$ (Case 3). The peak gains of each case are 6.5 dBi(Case 1), 7.6 dBi(Case 2) and 7.8 dBi(Case 3). The half power beam width(HPBW) of each case is $86{\sim}104^{\circ}$, and the overall HPBW is $160^{\circ}$.

• Journal of Science of Art and Design
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• v.4
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• pp.67-90
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• 2002

What is the semantic function of visual image in Contemporary art? This article proposes that representation is semantically still important in post-modernism as well as in modernism. The semantic function of representation has been changed by keeping pace with times. In modernism the 'outer representation' changed to 'inner representation', and in postmodernism the 'inner representation' changed to 'metaphorical representation'. The 'outer representation' means that image indicates a certain object or subject as the classical realism. In this case, the meaning of image is subordinate to an object, and a one-to-one correspond existed between the image and the object. Because this 'outer representation' is focused on an object but subject's intention, the indicative function of meaning is definite and singular. The 'inner representation' means that image exposes the fundamentals or process of an object. In this case, the meaning of image resolves itself into an absolute fundamental, and one-to-many correspond existed between the image and the object. Because this 'inner representation' is focused on essence and substance but an external form, the indicative function of meaning is inclusive and general. The 'metaphorical representation' means that image critically relates social constraint and condition as metaphor and allegory. In this case, the meaning of image is not subordinate to an object and a subject, and the image and the object indicate interactively. Because this 'metaphorical representation' is focused on interaction between subject, object, and interpreter, the indicative function of meaning is differant and ecological. This article focused on the representation because I believe that continuous thinking of totality can be opened by cognitive mapping, even though we never understand the world totally in the chaotic post modern age.