• Carbon letters
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• v.16 no.3
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• pp.147-170
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• 2015

In recent decades, there has been an increasing interest in the use of carbon fiber reinforced plastic (CFRP) in aerospace, renewable energy and other industries, due to its low weight and relatively good mechanical properties compared with traditional metals. However, due to the high cost of petroleum-based precursors and their associated processing costs, CF remains a specialty product and as such has been limited to use in high-end aerospace, sporting goods, automotive, and specialist industrial applications. The high cost of CF is a problem in various applications and the use of CFRP has been impeded by the high cost of CF in various applications. This paper presents an overview of research related to the fabrication of low cost CF using polyethylene (PE) control technology, and identifies areas requiring additional research and development. It critically reviews the results of cross-linked PE control technology studies, and the development of promising control technologies, including acid, peroxide, radiation and silane cross-linking methods.

• 전기의세계
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• v.26 no.3
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• pp.59-62
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• 1977

This study is to investigate the v-t characteristics gained by means of the Weibull distribution and to analyze the characteritics of fatigue breakdown caused by the A-C voltage of cross-linked polyethylene with and without void. By the results, it has in most cases reveald deteriorative breakdown in case of none-void, and that random breakdown or complex Weibull distribution of deteriorative breakdown and random breakdown in case of with void.

• 전기의세계
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• v.29 no.9
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• pp.577-583
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• 1980

This paper is intended to analyze the characteristics of breakdown of polyethylene dielectrics, which was caused by A.C. voltage after impulse fatigue, by using weibull distribution. The impact of impulse fatigue upon the accurance and development of tree and the impact of void upon treeing are investigated. From the results of experiment, it is found that the life of polyethylene subjected to impulse voltage is shorter than that not subjected to impulse voltage. And in the case of void existence, it's life comes to be short remarkably, and the breakdown is almost concentrated on its initiation. From the results observed by the microscope, it is found that the treeing phenomena varies according as whether impulse voltage was applied to polyethylene before being applied to A.C. voltage and whether polyethylene has void or not.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1897-1899
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• 2004

In this paper, in order to analyze the characteristics of degradation by salt water with insulation cover and OC wire(outdoor cross-linked polyethylene insulated wire) used in power receiving system, an experimental apparatus has been designed and fabricated. An insulation cover and OC wire were installed in an experimental apparatus, and degraded in each case of 2%, 5%, 10% salinity during 12 weeks. An optical microscope was used to observe a changing process of sample surface, and an electrical safety was analyzed by measuring dielectric breakdown voltages of samples. As salinity increased, so ununiformity of sample surface increased. The breakdown wasn't produced to 50kV about samples regardless of salinity, testing period.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.228-231
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• 2002

In this paper, we estimated the insulation properties of cross-linked polyethylene (XLPE) for ultra-high voltage cable. we have studied the dielectric characteristics of XLPE due to frequency and temperature variation. The dielectric characteristics were measured in the temperature range from $25[^{\circ}C]$ to $120[{^{\circ}C]}$. Also we measured in the voltage range of 1[V] to 20[V] according to the step voltage application method. From FT-IR spectrum as an analysis of physical properties, a strong absorption in wavenumbers 700 to $730[cm^{-1}]$, $1456[cm^{-1}]$ and 2700 to $3000[cm^{-1}]$ observed by the methyl groups$(CH_{2})$. From the analysis of DSC, the crystalline melting points of the specimen observed in the temperature $60[^{\circ}C]$ and $106.58[^{\circ}C]$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.183-189
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• 2012

Most of the domestic residential buildings have used the traditional radiant heating system, circulating hot water through the cross-linked polyethylene(PE-X) pipe buried in the floor panel of the heating space. New type of the heating panel was recently developed using heat pipes with double wicks. Some experiments were carried out in this study to verify the thermal characteristics of this heating system at the unit heating space which surrounded by outer space whose temperature of air be maintained scheduled value with time. Through the various experiments with several parameters, such as flow rate, inlet and outlet temperatures of hot water and the heating duration and so on, we found that the floor heating system with heat pipes was able to reduce the pumping power for hot water circulation by 4~31% compared with the conventional panel heating system using PE-X pipe. These results could be used for optimal design and efficient operation of the heating system as well as improvement of thermal comfort.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.69-74
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• 2003

To investigate the partial discharge and electric field distribution in cable joint parts, we measured the partial discharge and electric field in specimen. The specimens which cross-linked polyethylene(XLPE) and ethylene propylene diene ethylene(EPDM) are used to insulating material for underground cable md cable jointing parts. The polymers are used to insulating material in switchgear which is a kind of transformer equipment and in ultra-high voltage cable. Its using is increasing gradually, the electrical insulation properties are not only excellent but also mechanical property is excellent. And because it is possible to be made void of several type in insulator while it is produced, which the electrical field distribution is changed by void, it has a critical influence to insulator performance. The underground cable is connecting by the jointing material, insulating breakdown and the electric ageing which are caused by several mixing impurity and the damage of cable insulator layer, which reduced the life of cable while intermediate joint kit is connected. Therefore, the computer simulation is used to estimating insulator performance, XLPE is used to the insulating material of ultra-high voltage cable and EPDM is used to insulator layer in joint material kit, and which are produced as specimen. And it is analyzed the electric field concentrating distribution and partial discharge by modeling of computer simulation in void and cable joint kit.

• Carbon letters
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• v.16 no.1
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• pp.62-66
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• 2015

In this study, carbonized fibers were prepared by using acidically cross-linked LDPE fibers. The surface morphologies of the carbonized fibers were observed by SEM. The effects of cross-linking process temperatures were studied using thermal analyses such as DSC and TGA. The melting and heating enthalpy of the fibers decreased as the cross-linking temperature increased. The cross-linked fibers had a carbonization yield of over 50%. From SEM results the highest yield of carbonized LDPE-based fibers was obtained by cross-linking at a sulfate temperature ($170^{\circ}C$). As a result, carbonation yield of the carbonized fibers was found to depend on the functions of the cross-linking ratio of the LDPE precursors.

• Advances in materials Research
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• v.3 no.4
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• pp.233-242
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• 2014

Magnetic and conducting aniline sulfide resin cross-linked (ASC-Fe3O4) nanocomposite has been prepared in the presence of aniline sulfide resin (ASR), aniline, $Fe_3O_4$ coated by polyethylene glycol (PEG) and initiator. The magnetic properties of the resulting composites showed ferromagnetic behavior, such as high-saturated magnetization (Ms= 41 emu/g), and coercive force (Hc=1.5 Oe). The saturated magnetization was increased by increasing of $Fe_3O_4$ content and decreased by increasing aniline ratio. The transmission electron micrograph (TEM) and X-ray diffraction proved that nanometer-sized about 20-30 nm $Fe_3O_4$ in the composite. The average size of ASC-$Fe_3O_4$ nanocomposite with core-shell structure was about 50-60 nm, and polydisperse. This approach may also be extended to the synthesis and modification of other polymers. Electrical conductivity of aniline sulfide resin cross-linked (ASC) nanocomposite has been studied by four-point probe method and produced $3.3{\times}10^{-4}S/cm$ conductivity for it. The conductivity of the composites at room temperature depended on the $Fe_3O_4$, aniline ratio and doping degree. The thermogravimetry analysis (TGA) results showed that this resin is thermal resistance near of $500^{\circ}C$. So, It can be used for resistance thermal coating for military applications. $Fe_3O_4$-PASC nanocomposite has been flexible structure with electrical and magnetic properties.

• Hip & pelvis
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• v.34 no.2
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• pp.115-121
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• 2022

Purpose: The purpose of this study was to evaluate the wear and survival rates of third-generation ceramic heads on a conventional ultra-high molecular weight polyethylene liner. Materials and Methods: A total of 160 hips (147 patients with a mean age of 55.9 years) who underwent total hip arthroplasty using the third-generation ceramic head on a conventional polyethylene liner from March 1998 to August 2003 were reviewed retrospectively. Evaluation of the wear rate for 56 hips (49 patients) followed-up for at least 15 years was performed using the PolyWare program version 8 (Draftware Developers, USA). The Kaplan-Meier survivorship was also evaluated. Results: Linear wear and volumetric wear rates were 0.11±0.47 mm/year and 32.75±24.50 mm³/year, respectively. Nine revisions were performed during the follow-up period because of cup or stem loosening. The Kaplan-Meier survival rate, using cup revision or total revision total hip arthroplasty (THA) as the endpoint of analysis, was 93.7% at 15 years and 73.6% at 20 years. Conclusion: Because all revisions were performed between 15 and 20 years in our study, surgeons should pay greater attention to patients who underwent THA with ceramic-on-polyethylene bearing from 15 years postoperatively. Contemporary alumina ceramic on highly cross-linked polyethylene could certainly be a good alternative bearing couple providing better longevity.