• Journal of the Korean Geotechnical Society
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• v.31 no.10
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• pp.17-28
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• 2015

The strict regulations on eco-friendly construction and the significant reduction of natural aggregate resources have raised public concerns on the utilization of recycled aggregates for backfilling a power transmission pipeline trench. In this paper, the particle breakage of concrete-based recycled aggregates and river sand has been experimentally studied during the standard compaction test. The applied compaction energy does not significantly break the river sand particles down, and thus causes no change in the compaction curve, thermal resistivity, and particle gradation characteristics. On the other hand, considerable particle breakage was observed in case of the three recycled aggregates. Such particle breakage leads to enhancing compaction effort, reducing thermal resistivity, and changing particle gradation curve with finer particles that are broken during the first compaction. In addition, particle breakage is more dramatic in lower water contents because pore water may damp down the compaction energy.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.3
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• pp.238-245
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• 2017

Mg-Ni nanoparticles were synthesized by a physical vapor condensation method (DC arc-discharge) in a mixture of argon and hydrogen atmosphere, using compressed mixture of micro powders as the raw materials. The crystal phases, morphology, and microstructures of nanoparticles were analyzed by means of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). It was found that the intermetallic compounds of $Mg_2Ni$ and $Mg_2Ni$ formed with existence of phases of Mg, Ni, and MgO in Mg-Ni nanoparticles. After one cycle of hydrogen absorption/desorption process (activation treatment), Mg-Ni nanoparticles exhibited excellent hydrogen absorption properties. $Mg_2Ni$ phase became the main phase by aphase transformation during the hydrogen treatments. The phenomenon of refinement of grain size in the nanoparticle was also observed after the hydrogen absorption/desorption processes, which was attributed to the effect of volume expansion/shrinkage and subsequent break of nanoparticles. Maximum hydrogen absorption contents are 1.75, 2.21 and 2.77 wt.% at 523, 573 and 623 K, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1353-1359
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• 2001

The present study was undertaken to assess the influence of dimethyl-sulfoxide plus sucrose solution as a cryoprotectant on the adenosine triphosphate (ATP) content, the ultrastructure and the embryonic development of bovine oocytes matured in vitro. We measured the amount of ATP in cumulus cells enclosed oocytes (CO) or denuded oocytes (DO) equilibrated with or removed from the cryoprotectant (1.5 M DMSO + 0.25 M sucrose + 20% fetal bovine serum in physiological saline). As a result, the ATP contents in both CO and DO, equilibrated with the cryoprotectant, were significantly lower (p<0.05) than that of the each control group. However, ATP content of DO was recovered to the level of the control group ailer removal of the cryoprotectant, but failed to restore for CO. In the observation of the ultrastructure by a transmission electron microscope, all of the mitochondria in the ooplasm of CO and DO equilibrated with the cryoprotectant were swollen with peripherally located cristae following decreased electron density. However, a large proportion of these swollen mitochondria were restored to the normal shape which can be observed usually in the control group after removal from the cryoprotectant. To the contrary, the morphology of many mitochondria of the cumulus cells in CO were not recovered to that of the control group after removal of the cryoprotectant. CO with removed cryoprotectant had significantly lower embryonic development up to the blastocysts stage (p<0.05) after in vitro fertilization compared with that in the control group. These results suggest that the addition and removal of a cryoprotectant has a negative effect for the ATP content of cumulus enclosed oocytes. One of the factor(s) causing the lower embryonic development after removal of cryoprotectant, may be associated with ATP metabolism.

• Polymer(Korea)
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• v.38 no.2
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• pp.232-239
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• 2014

Poly(lactic acid)(PLA) nanocomposites containing various nanofillers were synthesized using the solution intercalation method. Organically modified bentonite clay (NSE), octadecylamine-graphene oxide (ODA-GO), and an NSE/ODA-GO complex were utilized as nanofillers in the fabrication of PLA hybrid films. PLA hybrid films with varying nanofiller contents in the range of 0-10 wt% were examined and compared in terms of their thermomechanical properties, morphologies, and oxygen permeabilities. Transmission electron microscopy (TEM) confirmed that most of the NSE and ODA-GO nanofillers were dispersed homogeneously throughout the PLA matrix on the nanoscale, although some agglomerate NSE/ODA-GO complex particles were also formed. Among the three nanofillers for PLA hybrid films, the NSE/ODA-GO complex showed the best improvement in film thermal stability. In contrast, NSE and ODA-GO exhibited the best improvement in tensile mechanical properties and oxygen barrier properties of the PLA hybrid films, respectively.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1481-1492
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• 1999

As Internet is popularized by the advent of Web concept having characteristics such as open network, user-friendly, and easy-usage, there are many changes in Information systems providing various information. Web is rapidly transferred traditional Information systems to Web-based Information systems, because it provides not only text information but also multimedia information including image, audio, video, and etc. Also, as information contents were changed from text-based simple abstract information to full-text information, there was appeared various document formats processing Full-text information. But, as they naturally demand large systems memory, long processing time, broader transmission bandwidth, and etc, estimating of these factors is necessary when constructing information systems. This paper focuses on how to design and construct information system processing full-text information and providing function of an integrated document. Primarily, we should review standard document format which is used or developed, and any document format is appropriate to process full-text information in review with viewpoint of information system. Also, practically we should construct information system providing full-text information based on PDF document.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.134-135
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• 2005

To improve mean-life and reliability of power cable, we have investigated volume resistivity and thermal conductivity showed by changing the content of acetylene black which is the component parts of semiconductive shield in underground power transmission cable. The sheets were primarily kneaded in their pellet form material samples for 5 minutes on rollers ranging between 70[$^{\circ}C$] and 100[$^{\circ}C$]. Then they were produced as sheets after pressing for 20 minutes at 180[$^{\circ}C$] with a pressure of 200[kg/cm]. The content of conductive acetylene black was the variable, and their contents were 20, 30 and 40[wt%], respectively. Volume resistivity of specimens was measured by volume resistivity meter after 10 minutes in the preheated oven of both $25\pm1[^{\circ}C]$ and $90\pm1[^{\circ}C]$. Thermal conductivity was measured by Nano Flash Diffusivity. The measurement temperatures of thermal conductivity using Nano Flash Diffusivity were both 25[$^{\circ}C$] and 55[$^{\circ}C$]. From these experimental results, volume resistivity was high according to an increase of the content of acetylene black. And thermal conductivity was increased to an increase of the content of acetylene black. And thermal conductivity were increased by heating rate because volume of materials was expanded according to rise in temperature.

• Journal of Game and Entertainment
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• v.2 no.3
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• pp.24-29
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• 2006

Nowadays, 'Interaction' is discussed not only in the multimedia field but also as a topic of daily life at the various viewpoints. And as the permmited limit of Interaction by Mutimedia Technology and audiovisual function is getting more activated, It is the time for us to have new understanding of a 'POSTER'. The Poster, as a one-sided information transmission media till now, is faced with its limitation in transmitting messages due to its unconformity between satisfaction of receiver' sdesire for information and installation space. This fact speaks for need of study about Digital Poster as an alternative communication method, and activation of Digital Poster Design Field. Therefore, I would like to present Design process and Examples by using Digital Poster for Maximizing the Communication Effect. And I expect the activation of Digital Poster Field by studying the possibility of development and various method of practical use of digital posters through presenting the examples.

• Archives of design research
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• v.21
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• pp.173-182
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• 1997

Technology represented by computers has made a ne w word, communication technology, and now we are at the time of opening New-Media, Multimedia, which sou nd a little unfamiliar. As the use of computers in produ cing movies, games and advertising commercial films in creases, very realistic and various transmission of infor mation is possible. This study has a purpose to suggest some possibilitie s by using softimage 3D Animation operated in the wor kstation which has an excellent function in producing co mputer animation Frist of all, I grasped the contents of light and textur e for an effective expression, the characteristics and ere ation methods of Motion Module which is the base of S oftimage 3D, and suggested general using plan through some examples of impact expression in computer animat ion to plan more lively production of computer artists, a nd produce quality products by grasping the adaptability and merits and demerits of the technique

• Journal of Internet Computing and Services
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• v.2 no.3
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• pp.19-25
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• 2001

An educational system using computers was first conceptualized by Dr. Donald Bitzer in the University of Illinois in the late 1950s. Since the PLATO system was developed in 1961, multilateral research were made for the last 30 years. Especially, the development of Internet and Information Technology has contributed to the advancement of the distance education system. This system has greatly changed the existing educational paradigm, As the result, new education system is being realized, This study suggests a distance education system based on ‘push’ technique, which is a means of active information transmission, In this system, the ‘push’ technique is combined with the existing distance education system. Through the combination, learning contents can be provided for learners without connecting the DB on the Internet. In addition, the process of getting new information is real-timed operation. Also, the treatment of item; and the algorithm of level-based item evaluation are devised in consideration of various levels of learners, so that evaluation of items appropriate to the levels of learners can be accomplished.

• Journal of the Korean Society of School Health
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• v.9 no.2
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• pp.239-248
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• 1996

This descriptive study was done to investigate the degree of knowledge and attitudes, the need of health education, and the relationship between knowledge and attitudes concerning AIDS in senior high school students. The data was collected from 386 senior high school students(200 boys, 180 girls) in K city. The data was gathered by a self reporting questionnaire, from Nov. 22nd to the 30th, 1995. Data was analyzed using the descriptive statistics methods: t-test, F-test, Pearson-Correlation Coefficient, GLM with the statistical computer package, SAS. The Result of this study were as follows : 1. The mean score of knowledge about AIDS was 42.70 from a total score of 58, showing significant differences between boys and girls (p<0.0001). 2. The mean score of attitudes about AIDS was 29.95 from a total score of 40, showing no significant differences between boys and girls. 3. The selected contents that the students want to learn were prevention, etiology, transmission, symptoms, and treatment of AIDS in that order. 4. The relationship between knowledge and attitude about AIDS show a positive correlation and is statistically significant(r=0.27, p<0.0001). The information obtained from this study will provi a useful data to develop a practical health education program about AIDS for senior high school students.