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Recycling of Waste XLPE Using a Modular Intermeshing Co-Rotating Twin Screw Extruder (모듈라 치합형 동방향회전 이축 스크류식 압출기를 이용한 폐 XLPE의 재활용)

  • Bang, Dae-Suk;Oh, Soo-Seok;Lee, Jong-Keun
    • Elastomers and Composites
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    • v.39 no.2
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    • pp.131-141
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    • 2004
  • The recycling of waste XLPE(crosslinked polyethylene), which is a major source of scraps from high voltage power transmission cables, has been discussed. The waste XLPE scraps were ground into fine powder with various sizes from less than $100{\mu}m$ up to about $1000{\mu}m$ using two types of tailor-made pulverizers. The compounds were prepared in a modular intermeshing co-rotating twin screw extruder at various conditions such as different compositions, types and powder sizes of waste XLPE, screw configurations and various polymer matrices (LDPE, HDPE, PP, PS). The mechanical and rheological properties and the fracture surface or the compounds were investigated. It was found that an improved impact strength was obtained from the compound with white XLPE powder pulverized from the scraps without outer/inner semi-conductive layers. Generally, the impact strength increases with the content of XLPE but decreases with the size of XLPE. Especially for LDPE, the extrusion was possible up to 80 wt% loading of XLPE. Also, the impact strength increases with the number of kneading disc blocks in the given screw configurations. The melt viscosity of the compounds increases with increasing XLPE loading. However, the higher shear thinning behavior of the compounds at common shear rates implies proper processibility of the compounds. In addition, the impact strength for other polymer matrices used increases with XLPE and it is noticeable that the impact strength of PS/XLPE (80/20 wt%) compound was improved twice that of pure PS.

A Historical Consideration on the Evolution of Competition in Offshore Fisheries (근해저인망류어업에 있어서 업종별 경합관계 형성에 관한 사적고찰)

  • 김병호
    • The Journal of Fisheries Business Administration
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    • v.35 no.1
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    • pp.23-56
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    • 2004
  • The offshore trawl fishery is seeking its survival way to overcome current management conditions in red, resulted from the bilateral agreement with China and Japan. However, this movement magnifies conflicts between fisheries on the contrary and it is thought to be impossible to get over current situations. For all that, this study is aimed at investigating how this current situations have occurred. The management freedom as response to the change in fishing conditions of a certain fishery, in case of Korea, is affected by institutional regulations. The example of this is controls on fishing gears, fishing vessels, and fishing grounds. The most exposure of this control is a segmentation of institutional fisheries. The initial segmentation of the offshore trawl fishery in Korea was occurred in the period of Japan's colonization when the degree of use of fishing grounds was limited geographically. At that time, fisheries were divided by fishing areas, but it did not divide the fishery itself. The large - sized fishing vessels were developed politically to be more competative to Japanese fishing vessels since 1950s. During this time, the trawl fishery was merged into current Eastern trawl fishery and South - Western trawl fishery. It was also inevitable to divide into the pair trawl and single trawl fishery as a result of the physical mergency between Western trawl and Southern trawl fishery. In order to develop the trawl fishery, new licenses were issued on the shrimp trawl fishery, through which it was expected to boost the trawl fishery. As opposed, the shrimp trawl fishery was changed into the mid - sized trawl fishery, targeting on the eastern fishing areas and the large - sized trawl fishery was developed since the late of 1970s with the development of filefish processing industry. The large trawl fishery that led in development of offshore trawl fishery since the late of 1950s was started to divide into a pair trawl and single trawl according to the fishing method and capital power. It finally became an institutionally independent fishery in 1980s, respectively. Looking into these historical process, the segmentation of the trawl fishery is thought as a result of the lack of long - term perspective and as a production of trial and error resulted by unprepared policy. As a result, these segmentation of fisheries roles as critical obstacles in harmonization of fisheries and in overcoming of current situations. Therefore, the review of this institutional segmentation of the offshore trawl fishery should be taken for an optimal redistribution of fishing grounds suits with business and fishing technology. For this, the fishery must be divided into large capitalized fishery and small - mid fishery with consideration of capital, fishing method, and the condition of use of fishing grounds. In addition to this, by limiting outline of fishing ground that the large fishery can harvest, it must allow for the small - mid fishery to catch with its own boundary. Furthermore, by launching buyback programs on the trawl, eastern trawl, pair trawl, it can provide broader fishing grounds where the fishery can harvest with management freedom.

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A Study on Multi-band Antenna for Mobile using Coupling Feeding (커플링 급전을 이용한 모바일용 다중대역 안테나에 관한 연구)

  • WANG, Cheng;YOON, In-seop;HWANG, Sun-gook;YAN, Xiao-jia;PARK, Hyo-Dal
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.7 no.4
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    • pp.188-194
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    • 2014
  • In this paper, an antenna which has quad band in LTE (0.746 ~ 0.798 GHz), GSM(0.824 ~ 0.960 GHz), DCS(1.71 ~ 1.88 GHz), WCDMA(1.91 ~ 2.17 GHz) is proposed. An antenna size is $122mm{\times}50mm{\times}0.8mm$ on FR4(${\epsilon}_r=4.4$) ground substrate. In the proposed antenna, branch line is applied to the conventional PIFA architecture to achieve multi-bandwidth. Coupling power supply is applied for a wide bandwidth. Result of the measurement is as follows. When the low frequency, the antenna presents gain of 0.93 ~ 1.92dBi, and radiation efficiency of 49.60 ~ 76.35 %, and When the high frequency, gain is 2.19 ~ 4.66dBi, and radiation efficiency is 60.40 ~ 80.01 %, and with a VSWR < 2 (${\leq}-10dB$)measurement results for standard satisfies all band. Judging from the result, proposed multiband antenna is expected to be applied. B4G mobile terminals since the antenna shows an outstanding performance.

A Study of the Core Factors Influencing the Golfer Satisfaction with Golf Courses in Korea (한국골프장의 이용자 만족도 결정 요인에 관한 연구)

  • Ryu, Chang-Hyun;Kim, Yoo-Il
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.5
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    • pp.26-34
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    • 2008
  • This study was conducted to investigate the correlation between golfer satisfaction and the diverse variables of golf course design and operation from the golfer's point of view. It was intended to reflect the various expectations and desires of golfers regarding golf course design and operation. The study was conducted on 119 golf courses in Korea, and 309 questionnaires were collected and analyzed. Results are summarized as follows. First, the most influential operational service variables on golfer satisfaction were "appearance of the golf courses", followed by "staff service", and "greens fee". Second, the most influential course design and maintenance factor variables on satisfaction were "course maintenance status", "teeing ground characteristics", and "landscape architecture". Third, based on the results shown in these two areas, a linear regression analysis was conducted to synthetically explain "operational service" variables and "course design and maintenance" variables. As a result, it was found that the explanation power of the synthetic model was 36.5%, and a model appropriateness test was found to be positive. As a result of a regression analysis of the synthetic model affecting golfer satisfaction, the most influential factors were "course maintenance status" followed by "landscape architecture", "tee characteristics", and "staff service". Regarding coefficient values, course maintenance status had an influence of 21.8% followed by landscape architecture at 20%, tee characteristics at 17.7%, and staff service at 15.5%. These results were found to be different from preceding studies that emphasized golf course operational service.

Treatment of Liquid Waste Containing Highly Concentrated Ethylenediaminetetraaceticacid by Using Underwater Electrical Discharge (수중 전기방전을 이용한 에틸렌디아민테트라아세트산 폐액의 처리)

  • Jo, Jin-Oh;Mok, Young-Sun;Kang, Duk-Won
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.5
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    • pp.564-570
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    • 2007
  • This study investigated the treatment of liquid waste containing highly concentrated iron(III)-ethylenediaminetetraaceticacid (Fe(III)-EDTA) of 70,000 mg/L by an underwater electrical discharge process using low voltage and high current. When AC voltage is applied to the discharging electrode with the other electrode grounded, the temperature of the liquid waste around the discharging electrode rapidly increases, and at the same time, hydrogen and oxygen gases are formed at the electrode as a result of electrochemical reactions. Ultimately, gases formed by vaporization of water and electrochemical reactions cover the electrode. Since the liquid waste is electrically conductive, it elongates the ground electrode up to the border of the gas layer, where electrical discharge occurs. Without hydrogen peroxide, electrical discharge was able to remove about 50% of Fe(III)-EDTA. As the concentration of hydrogen peroxide added increased, the removal efficiency of Fe(III)-EDTA increased. When the molar ratio of hydrogen peroxide to the initial Fe(III)-EDTA was higher than 24.7, more than 80 g of Fe(III)-EDTA was removed with an energy of 1 kWh. A comparison between tungsten and steel electrodes showed that electrode material did not affect the Fe(III)-EDTA removal. In the present underwater electrical discharge process, the removal of Fe(III)-EDTA was completed within 30 min at molar ratios of hydrogen peroxide to the initial Fe(III)-EDTA higher than 24.7.

The Aspectual Theory of the Cybercharacter (사이버캐릭터의 위상론)

  • 이선교
    • Archives of design research
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    • v.12 no.4
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    • pp.182-190
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    • 1999
  • There has been the rapid change of paradigm with the overflow of terms related to computers such as information, digital, cyber, virtual world and the change of time concept on the ground that it is common to change the world into virtual time. This study is about cybercharacters working in air-broadcasting with rapidly-developing internet, The cybercharacters including 3D animation developed from 2D animation are know to be manufactured with use of electronic mediun and computers and to exist in electronics. Though the emergence of the cybercharacters has a lot of gflnetic roots according to their objectives, they have in common that they are made by 3D graphics and they work in the virtual space, The great traits of the cybercharaters lie in the extension of interfacial function and ecological growth. In the cyberspace the interface, the meeting point between a computer and its users is the most important, The cybercharacters as medium providing new ruman interface become effective with growing interest in virtual reality, The cybercharacters also keep the ecological traits, They can also bring about added value with infusion of image and development of the network, These cybercharacters can also play the important parts in the continually developing cyberspace, The successful birth of the cybercharacter are based on, the technological power. assistance of fund and the ctrltural background, The information-entertainment of the cybercharacters functions well with the accompinimene of these three things, The cybercharacters can make a subject which keeps single issue as a central point of the virtual realty, The cybercharacters can also be connected with equity of "Korean knowledge information society" in the cultural rule of the internet and sociocul tural identity, identity.

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A Study on Design Verification of Radio Measurement System for Interplanetary Space (태양-지구 간 공간 전파 관측 시스템 설계 검증)

  • Jeong, Cheol-Oh;Park, Jae-Woo
    • Journal of Satellite, Information and Communications
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    • v.6 no.2
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    • pp.97-101
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    • 2011
  • Interplanetary space between Sun and Earth is area of flowing very fast solar wind which is contained X ray, flare, corona mass, etc. occurred Sun surface to Earth. This solar wind is affected directly to Earth magnetosphere and ionosphere so that this bring out broadcasting and communication interruptions, satellite operation obstacles and power gird defects and etc..Solar wind flow in interplanetary space is measured as solar wind speed, density and direction by measuring scintillation value to be produced during radio source is passed through solar wind. The wider effective collective areas and the more radio sources, accuracy of solar wind measuring is got higher. Function test was performed using 3 tiles which was manufactured as prototype. Restriction of quantity of tiles, test was performed to confirm whether measured beam pattern is complied with requirement or not. In this paper, it is shown design and their specification of ground interplanetary radio measurement system as well as technical issues and resolutions which were raised during design phase. Also result of function verification test using prototype is suggested. It is confirmed that measured beam pattern was met with requirement.

The Asian mode of production of Japanese Manga Higajima -The protests of the Political Structure and Asian mode of production (일본 만화 <피안도(彼岸島(Higajima))>와 아시아적 생산 양식 아시아적 생산양식의 정치구조와 투쟁)

  • Lee, Ho-Young
    • Cartoon and Animation Studies
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    • s.25
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    • pp.109-132
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    • 2011
  • The Vampire has relatively universal images in through the cultural and verbal usages. The comic Higajima and movie display the latest image of Japanese Vampire of asian mode of production. After the Meiji political reformation of 18th Century, Japanese had rapidly changed into European style in every places. However, the Higajima is denied the structural changes, it is insisted that the changing is only the skin deep and colour of hair but the structure of the society is same as feudal Japan. Asian mode of production is claimed by Karl Marx, according to him, it is before the historical developing model in Europe and it was controversial. The major character of modern Japanese history would be the change of hierarchy of king-shogun-samurai-peasant based on the regional ground. The feudal structure is changed by the Meiji reformation and Japan was rushed for the westernized country rather than the asian mode of production. However, Higajima argued that the changing is just the clothes of ruler but the democracy and individual citizenship was lost in that reformation. Vampire is cursed creature that cannot see the sun and it has not the functioned as a human organ. For human it is dead but this creature actively moves and stronger than human and much superior than human in every aspects. It is managed the feeding through the suck the human blood and power to seduction. Even it is not exist, it is quite symbolic phenomenon of cultural usage of superior entity of chain of feeding. The aim of this paper is display the symbolic code Vampire of Asian mode of production in Higajima and political struggling of Japan in actual. To search of the cultural meaning and possibility of the Korean solution of modernity.

Experimental Study on the Behavior Characteristics of Single Steel Pile in Sand Subjected to Lateral Loadings (사질토 지반에서 수평하중에 따른 단일강관말뚝의 거동특성에 관한 실험적 연구)

  • Kim, Daehyeon;Lee, Tae-Gwang;Kim, Sun-Hak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3548-3556
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    • 2015
  • In order to fulfill the needs of reliable and economically feasible foundation, engineers should consider not only the working load that can endure extreme conditions but also apprehending precise behavior of continuous dynamic load while designing the foundation of offshore wind power generators. To actualize the foundation, a model pile was made in miniature. Also, calibration chamber was made and a 500mm height of sand-bed was made to perform "static lateral load experiment" and "repetitive loading experiment", total of two Lateral load tests. As a result, in Static Lateral load test, the bigger length/diameter of model pile led an increase in load displacement. However, when performing "Cyclic Lateral load test", the increase in number of under loading led the decrease in horizontal displacement from each repeated lateral load. While performing Static Lateral load test and repeated loading experiment, we could observe the decreasing in the rate of ultimate lateral load capacity increase of the pile. Also, it turned out that the higher relative density of the ground, the lower ultimate lateral load capacity by repeated horizontal loading.

Hydraulic and Numerical Model Experiments of Flows in Circulation-Water-Pump Chambers (순환수취수펌프장 내의 흐름에 대한 수리 및 수치모형실험)

  • Yi, Yong-Kon;Cheong, Sang-Hwa;Kim, Chang-Wan
    • Journal of Korea Water Resources Association
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    • v.38 no.8 s.157
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    • pp.631-643
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    • 2005
  • The objective of this study is to perform hydraulic and numerical model experiments of the flows in circulation-water-pump(CWP) chambers of combined cycle power plants (CCPP) to be built and to suggest improvement plans if the flows might cause a serious problem on the operation of CWPs. Hydraulic model was constructed in a scale of 1 to 20 using acrylic sheets and a two dimensional numerical model used was RMA2. To evaluate results of Hydraulic and numerical model experiments, evaluation criteria of flow conditions in the intake canal and CWP chambers were determined. Vertical vorticities obtained from numerical simulations for the initial plan of CCPPs were qualitatively compared with results of hydraulic model experiments and the formation possibility of a large scale vortex, one of the flow evaluation criteria, was evaluated. The initial plan was found not to satisfy the flow evaluation. Nine improvement plans were devised and numerically simulated. Four alternative plans among nine improvement plans were selected and hydraulically experimented. On the ground of the results of hydraulic model experiments, a final improvement plan, one of four improvement plants, was suggested. When CWP chambers and intake canals were designed with spatial constraints, flow separating wall and guide walls were found to improve flow conditions in CWP chambers.