• Journal of the Korean Magnetics Society
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• v.24 no.2
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• pp.66-69
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• 2014

The spreading tube of X-ray cathode tube displayed with an electromagnetic finite element method was designed. To analyze a feature design and the concrete coordinate performance of soft X-ray tube modeling, the orbit of electron beam was simulated by OPERA-3D SW program. The fixed conditions were the applied voltage, the temperature, the work function of thermal electron between cathode and anode of tungsten. Through the analysis of distribution of electron beam and the variation of dividing region, the design of soft X-ray spreading tube equipped with two cross filaments was optimized.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.6
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• pp.477-485
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• 2006

A study on frost prevention of fin-tube heat exchanger is experimently performed by spreading antifreezing solution on heat exchanger surface. It is desirable that the antifreezing solution spreads completely on the surface forming thin liquid film to prevent frost nucleation and crystal growth and to reduce the thermal resistance across the liquid film. A small amount of antifreezing solution falls in drops on heat exchanger surface using two types of supplying devices, and a porous layer coating technique is adopted to enhance the wettedness of antifreezing solution on the surface. It is observed that the antifreezing solution liquid film prevents fin-tube heat exchanger from frosting, and heat transfer performance does not degrade through the frosting tests. The concentration of supplied antifreezing solution can be determined by heat transfer analysis of the first row of heat exchanger to avoid antifreezing solution freezing due to dilution by moisture absorption.

• Laser Solutions
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• v.3 no.3
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• pp.21-29
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• 2000

For the direct metal shape processing the powder feed device which is different from the widely used in rapid prototyping. is developed, The three dimensional object is shaped with the melting metal powder. The developed research has applied to rapid prototyping in ultraprecision for MEMS and medical science fields required of rapid manufacture of complex shape. The goal of this study make 3D model which has precision accuracy. Powder spreading apparatus has been more improved because that the control of powder spread is very important in layer manufacturing. It consists of the vibration motor, nozzle and tube which supplies various metal powder. This apparatus could control the spreading velocity that could control powder spreading thickness. Laser on/off switch was adapted because laser scanning velocity must be preserved constantly to prevent heat transformation of laser overheating. The error between sintered thickness md experimental one occurred by shrinkage in sintering melting process. The problem of heat transformation was solved by On/Off switching system.

• Molecules and Cells
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• v.42 no.8
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• pp.589-596
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• 2019

${\beta}Pix$ is a guanine nucleotide exchange factor for the Rho family small GTPases, Rac1 and Cdc42. It is known to regulate focal adhesion dynamics and cell migration. However, the in vivo role of ${\beta}Pix$ is currently not well understood. Here, we report the production and characterization of ${\beta}Pix$-KO mice. Loss of ${\beta}Pix$ results in embryonic lethality accompanied by abnormal developmental features, such as incomplete neural tube closure, impaired axial rotation, and failure of allantois-chorion fusion. We also generated ${\beta}Pix$-KO mouse embryonic fibroblasts (MEFs) to examine ${\beta}Pix$ function in mouse fibroblasts. ${\beta}Pix$-KO MEFs exhibit decreased Rac1 activity, and defects in cell spreading and platelet-derived growth factor (PDGF)-induced ruffle formation and chemotaxis. The average size of focal adhesions is increased in ${\beta}Pix$-KO MEFs. Interestingly, ${\beta}Pix$-KO MEFs showed increased motility in random migration and rapid wound healing with elevated levels of MLC2 phosphorylation. Taken together, our data demonstrate that ${\beta}Pix$ plays essential roles in early embryonic development, cell spreading, and cell migration in fibroblasts.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.155-169
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• 2013

This research aims to consider the participatory behaviors and the relationship building of the Hong Kong Korean Wave fans on YouTube and to explores the effect of the behaviors in order to spread the Korean Wave. Furthermore, this research seek ways of developing the Korean Wave contents based on fan participation on YouTube. The research conducted both Focus Group Interview and three rounds of email interviews with the Korean Wave fans in Hong Kong. They actively participated in expressing themselves, replying to other comments, and providing video contents as a fan. Also, the fans delivered the YouTube video contents to other Social Network Services(SNS), including facebook, and online fan pages in order to build ties with friends and other the Korean Wave global fans in daily lives. Their YouTube participation contributes to creating two-way communication between the Korean Wave and its global fans by spreading and re-creating the Korean Wave contents.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.469-471
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• 2013

In this study, we measured the anti-bacterial activity of radioisotope Lu-177 using a new laboratory instrument. The disk method used for the measurement of existing anti-bacterial antibiotics is drug diffusion into the medium. To measure the antimicrobial activity of a radioisotope, a new type of laboratory instrument is necessary to prevent the drug from spreading and the present invention was thus tested. In the medium, a space isolated separately for radioisotope injection was used to prevent the radioisotope from spreading and radioisotopes are actually injected by this system. We found that the antibacterial activity increased according to the radiation dose increases. It is expected that, through the present study, measuring the antibacterial activity of the other radioisotopes easily in the laboratory will be possible.

• 한국해양학회지
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• v.30 no.4
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• pp.355-364
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• 1995

A heavy fluid is injected to a rotating cylindrical container of flat or inclined bottom filled with homogeneous lighter fluid. Continuous flow-in and spreading patterns over the bottom of the container are observed and at the same time upper-layer motions induced by the movement of the heavy fluid are traced by thymol blue solution. Regardless of bottom geometry, the injected denser fluid is deflected toward "western wall" and continuous its path along the boundary with radial spreading which occurs in the bottom boundary layer to make a quite asymmetric flow. When the bottom contains a slope(${\beta}$-plane), increased pressure gradient causes the fluid move faster to produce a stronger Coriolis force. This makes the width of the flow narrower than that of f-plane. But, when the denser flow reaches the southern part of the container, a local-depth of denser fluid increases (much greater than the Ekman-layer depth) such that the spreading velocity along the wall is reduced and the interfacial slope increases to make the upper-layer adjust geographically to have oppositely directed upper-layer motion along the interfacial boundary. The role of the denser fluid in terms of vorticity generation in the upper-layer is such that it produces local topographic effect over the western half of the container and also induces vortex-tube stretching which is especially dominant in the f-plane.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.127-139
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• 2019

This study aims to explore the impressive experiences of university students on YouTube media and to find ways to improve personal media as useful consumer information. 44 university students were selected, and data on the experience of using YouTube were collected and analyzed by applying the critical incident technique. As a result, the positive responses to personal media were derived from 'enhancing C2C information capabilities', 'consumer-centric usability', 'attractive information creators', 'a sense of the sameness', and 'fresh and entertaining information'. Negative responses were derived from 'spreading of harmful information', 'distrust in information creators', 'inducing excessive advertising and impulse buying', 'media addiction' and 'relative deprivation'. In addition, improvement of the personal media has been suggested. This study has differentiation and significance as a qualitative data for understanding consumer's perception and experience of personal media.

• Journal of the Korean Geosynthetics Society
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• v.7 no.3
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• pp.1-7
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• 2008

The geotextile tube shall be sewen with geotextile longitudinally in the shape of hose and it shall be filled hydraulically through filling ports at the proper intervals to construct structure. Geotextile container shall be sewen after spreading of geotextile on the split barge and sealed shut after the filling soil, and then moved and positioned at the required position. And the geotextile container passes through the bottom of barge by opening split barge and drops to the seabed to form structure. This structure for the ${\bigcirc}{\bigcirc}$ project, UAE and we would propose that geotextile containment for core material of power plant breakwater to be constructed for lower bunds with containers up to -4.0m and do upper parts with the structures of tube up to 0.0m. For the application of proposed geotextile containment, review on stability of breakwaters and design consideration were adopted. The evaluation on stability of geotextile containment was classified by 3 items, internal design consideration for material selection, reviews on stability for individual and global structure. In this research, the geothermal analysis was performed to estimate the geothermal behavior of central breakwater. Central breakwater is located boundary of intake and outfall channel, it is mean that the central breakwater is thermal boundary of intake low temperature sea water and outfall high temperature sea water. Therefore, it is required to be designed a low permeability to ensure no mix of intake and outfall waters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.774-779
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• 2008

An experimental study on the micro-supersonic jet flow fields has been carried out. A sonic nozzle of 440 ${\mu}m$-exit diameter and a Laval nozzle of 800 ${\mu}m$ exit diameter with the nozzle exit Mach number 2.0 were fabricated by stretching a micro Pyrex glass tube for the present experiments. Schlieren flow visualization and Pitot pressure distribution of the jet flow field were obtained. Representative characteristics of the jet flow fields such as, supersonic length, jet core length, similarity of the velocity field, and jet spreading rates, have been observed. All the results were compared to previous observations of larger supersonic jets of higher Reynolds numbers, and it was found that overall characteristics of the micro supersonic jet are qualitatively similar as those of the higher Reynolds number jets, except the jet core length and the jet spreading rate.