• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2130-2135
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• 2007

Operating characteristics of a loop heat pipe (LHP) having a bypass line was investigated experimentally. The LHP had a sintered metal wick as a capillary structure and methanol as a working fluid. The sintered metal wick was made of stainless steel of which the average pore size was 5 ${\mu}m$and porosity of 47%. A bypass line of a small diameter was attached between the vapor escape passage and the liquid reservoir. The dimension of the flat evaporator was $50(L){\times}40(W){\times}30(H)$ mm and that of the condenser was $50(L){\times}40(W){\times}11(H)$ mm. Wall and pipe material of the LHP was stainless steel and heating area was 35(W) mm${\times}$35(L) mm. The inner diameters of vapor and liquid transport lines were 4.0 mm and 2.0 mm, and the lengths of the two lines were both 0.5 m. The LHP was tested for three different tilt angles of horizontal, favorite tilt, and adverse tilt. The thermal load range was up to 290 W at the condenser above evaporation position. Furthermore, the effect of a bypass line on the start-up transient as well as steady-state operation was presented and discussed.

• Applied Microscopy
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• v.12 no.1
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• pp.49-56
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• 1982

A case of systemic cryptococcosis developed in 4 year old boy was described and illustrated by light and electron microscope. Light microscopically, the upper dermis of the skin showed chronic nonspecific inflammation with numerous spherical spores surrounded by a clear halo created by the wide gelatinous capsule. Ultrastructurally, the C. neoformans showed the wide capsule containing microfibrils that appeared to radiate from the cell wall and to coil and interwine in various directions. The cell was uninucleate with a single nucleolus. Along the inner nuclear envelope, numerous small vesicles were present. In addition, C. neoformans presented membranous organelles derived from the plasma membrane and comparable to bacterial mesosomes.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.167-176
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• 2006

In this paper we show that solutions of the nonlinear Nernst-Planck equation possesses the quadruple-layer structure near the interface when the electrolyte receives a high frequency forcing such as a high-frequency alternating current. Very near to the interface wall, the well-known, classical Stern layer exists. Near to the Stern layer we have the secondly thin layer (to be called inner layer in this paper) where the ion concentrations behave under the same frequency as the external forcing. However, in this layer, the positive and negative ion concentrations develop with the time phase 180-degree different from each other. Next to this second layer, we have the third layer (called middle layer) in which two ion concentrations change with the time period double the forcing, and both concentrations behave in the same time phase. In the outermost layer, i.e. the forth layer, (called outer layer) the ion concentrations show the same-phase development as the third one but decaying very slowly in time. Our assertion is mostly based on the 1-D numerical simulation for the Nernst-Planck equation under a high frequency AC field assuming that the quadruple layer is very thin compared with the length scale representative of the bulk region.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1323-1330
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• 2000

Recently, injection molding process became more popular than ever to produce large quantities of high precision products or optical products. Especially, optical disk that was made by injection mol ding process has been used for many years as a music play media or computer sub-device. The density of data in disk media has been increased continuously. But those optical disks can cause sensorial problems because of high birefringence or deformation from the residual stresses in the media. Therefore, it is necessary to study the effects of various process conditions on the final bireffingence structure in injection-molded disks for producing precision injection-molded products. In the present paper we have focussed on the effect of holding and compression pressures on the optical anisotropy remaining in the MOD by examining the gapwise distribution of birefringence and extinction angle. The effect of holding pressure was found to form the inner two bireffingence peaks. But the effect of compression pressure on the bireffingence distribution was found to make the uniform distribution near the center in the gapwise direction. Finally, the value of the birefringence near the wall decreased as the mold temperature increased.

• Applied Microscopy
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• v.18 no.1
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• pp.49-59
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• 1988

Fine structures of the testis and vas deferens in the fall-web worm, Hyphantria cunea Drury, are studied with electron microscope. Adult worms have single testis close to the midlines of the abdomen. Testis is composed of 4 follicles which are incompletly separated from each other and bounded together by a peritoneal sheath. The peritoneal sheath consisted of outer cuticular layer and two kinds of inner layers, in which glycogen particles are dispersed commonly. These two layers are divided by the morphology of cytoplasmic granules. Follicular epithelium forming the wall of the follicles have melanin pigment granules, and trachea or tracheoles are extended through this epithelium. In the cysts of adult testis, matured spermatozoa are grouped together in bundles and after releasing the sperm bundles to the vas deferens, lamellar shaped lysosomes appeared in the cytoplasms of the cyst cells. The number of spermatozoa per cyst is exactly 256 ($2^8$), this number is characteristics of the Lepidoperan species. Vas deferens is a tube with a fairly thick bounding epithelium, a basement membrane and a layer of circular muscle outside it. At the apical portion of the epithelial cells, microvilli are well developed. And in the cytoplasms of these cells, numerous excretory granules are observed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.7
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• pp.77-83
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• 2022

When carbon dioxide in a liquid becomes supersaturated, carbon dioxide gas bubbles are generated in the liquid, and they ascend to the surface as they develop further. At this time, the inner wall of the cup with carbon gas attached is known as the entrapped gas cavity (EGS); once an EGS is established, it does not disappear and will continuously create carbon bubbles. This bubbling phenomenon can be activated or suppressed by changing the properties of the solid surface in contact with the carbonated liquid. In this study, the foaming of carbonated liquid is promoted or suppressed by modifying the wettability of the surface. A micro/nano surface structure is formed on the surface of an aluminum cup to produce a superhydrophilic surface, and a superhydrophobic surface similar to a lotus leaf is synthesized via fluorination. Experiment results show that the amount of carbon dioxide bubble generated differs significantly in the first few seconds depending on the surface, and that the amount of gas generated after it enters the stabilization period is the same regardless of the wettability of the cup surface.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.79-92
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• 2011

In this study, wave pressure of short-period gravity waves and tsunami acting on the upright section of the horizontal-slit type caisson placed on the impermeable or permeable seabed, which is a well-known permeable breakwater with a good wave controlling ability, are investigated via numerical simulations. Further, the permeable seabed was modeled as the porous media with porosity of 0.4. Using the numerical results, the effects of the seabed conditions on the wave pressure on the front wall and inside wall of the chamber have been studied. In the numerical simulations, short-period gravity waves and tsunami(solitary wave or bore) with the same amplitude to the gravity wave are considered. A numerical wave tank is used, which is able to consider a gas-liquid two-phase flow in the same calculation zone. Numerical results show that the wave pressure of the tsunami was 3~5 times higher than the short-period gravity waves acting on the front wall and it was 2~4 times higher than the short-period gravity waves acting on the inner wall.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.742-748
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• 1988

The macro-and microstructure of Chinese cabbage used for Korean Kimchi preparation were examined and the texture characteristics of raw cabbage leaf and salted or blanched leaves were evaluated by cutting test. The length and thickness of leaf stalk increased with the order of pyllotaxis, but the thinning effect of outermost leaves was observed. The microstructure of cut-profile of stalk showed densely compacted vascular systems aligned in the center of stalk and the outer space was filled with large parenchima cells. Due to this structure, characteristic cutting curves were obtained by cutting test, composing three peaks of cutting for inner surface skin, center vascular system and outer surface skin. Salting and blanching increased the cutting force mainly due to the increase of Gutted cell wall number caused by the structure collapse.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.41-44
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• 2008

The PCT that supports the walls of long span temporary shoring facility is previously manufactured in the way of prestressing, and it which is composed of concrete is improved precast structure to satisfy enough stiffness. The components of PCT are manufactured as a fixed form, and they are close to the inner side of the wall of temporary shoring facility by fixed means in PCT. PCT system as support structure is that the ends of concrete filled segment members are united by the means of connection and also they have connection hole. In this study, PCT has enough bearing power for the long span temporary shoring facility, and also make the term of work reduce due to that the time of curing reduce through the method of precast.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.7
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• pp.937-944
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• 1999

The near-wall flow structures of turbulent boundary layer over riblets having semi-circular grooves were investigated experimentally for the drag decreasing ($s^+=25.2$) and drag increasing ($s^+=40.6$) cases. The field of view used for tho velocity field measurement was $6.75{\times}6.75mm^2$ in physical dimension, containing two grooves. One thousand instantaneous velocity fields over the riblets were extracted for each case of drag increase and decrease. For comparison, five hundreds instantaneous velocity fields over a smooth flat plate were also obtained under the same flow conditions. To see the global flow structure qualitatively, the flow visualization was also performed using the synchronized smoke-wire technique. For the drag decreasing case ($s^+=25.2$), most of the streamwise vortices stay above the riblets, interacting with the riblet tips. The high-speed in-rush flow toward the riblet surface rarely influences the flow inside tho riblet valleys submerged in the viscous sublayer. The riblet tips seem to impede the spanwise movement of the longitudinal vortices and induce secondary vortices. The turbulent kinetic energy in the riblet valley is sufficiently small to compensate the increased wetted area of the riblets. In addition, in the logarithmic region, the turbulent kinetic energy are small or almost equal to that of a smooth flat plato. For the drag increasing case ($s^+=40.6$), however, the streamwise vortices move into the riblet valley freely, interacting directly with the riblet inner surface. The penetration of the high-speed in-rush flow on the riblets increases tho skin-friction. The turbulent kinetic energy is increased in the riblet valleys and even in the outer region compared to that over a flat plate.