• Journal of the Korean Society of Safety
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• v.6 no.2
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• pp.31-36
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• 1991

Quenching effects of acetylene and hydrogen into oxygen detonation by using detonation arrester ［DA］are studied in this paper. The experiments were carried out in cylinderical shock tube. 5m long, 30mm dia., with stolchlometric ratio ［SR］of each gas and 10-l20$\mu$ Cell Size of brass and Stainless Steel of DAs were installed in it To clarify arresting ability correlation with initial pressure, Pi, critical thickness, Tct, and shapes of supporting panel of DA are also investigated It is found that ­detonation velocities has most dependency on Pi, it shows notable changes around 0.5kgf/$\textrm{cm}^2$ for hydrogen, 0.15kgf/$\textrm{cm}^2$ for acetylen respectively, ­DA can be safety device able to arrest shock wave of detonation, ­over Tct flame transmission might be only the factor has to be considered, ­acetylene seems to be much more stronger detonation characteristics than hydrogen because of reaction heat.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.233-234
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• 2004

각종 재료의 음향투과손실을 간단히 비교 시험할 수 있는 관내법이 향후 국제규격으로 제정될 것에 대비하여 우선 KS 규격 제정을 목적으로 제반 특성평가를 수행하였다. 이를 위해 임피던스관을 제작하고, 관 벽을 따라 시편을 지나 마이크로폰 위치까지 전달되는 진동량, 무반사처리부의 흡음률 등 기본적인 특성을 살펴보았다. 최종적인 검증을 위해 몇 가지 시편에 대해 투과손실을 측정하고 이론적 해석에 의한 예측 값과 비교하였다.

• Journal of radiological science and technology
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• v.21 no.2
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• pp.11-18
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• 1998

Single phase, narrow beam X-ray attenuation data were obtained using various construction materials concrete, white block, red block, 3 hole block, gypsum board, artificial marble, cement, plate glass, wood, and lead. Tube voltages of 60, 80, 100, 120 kVp were employed and the resulting curves were compared to transmission data found in this report. The shielding methodology and the derivation of equations used for determination of barrier requirements were presented in NCRP 49. We could calculate the X-ray exposed dose after attenuation and thickness of protection barrier in the clinic facilities accordingly. For the purpose of maximizing the benefit/cost ratio to diagnostic shielding, various construction materials must be installed carefully and attnuation rate considered thoroughly.

• Journal of Plant Biology
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• v.10 no.3_4
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• pp.1-3
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• 1967

Observations were made on Crinum and Catharanthus pollen growth in artificial media by an ultraviolet transmission fluorescence microscope showing synergistic effect on pollen growth with calcium (Ca) and aureomycin. Bright yellow fluorescence of aureomycin enabling to trace out at tissue or cellular level did reveal that the greater accumulation of fluorescence occurred in the pollen tube wall if Ca was supplemented to the media than when aureomycin alone was present. The promotive pollen growth the media of Ca alone was further enhanced by the addtion of aureomycin. It was assumed that the promoted pollen growth with aureomycin in the Ca media was probably brought about by a supporting role of aureomycin in the Ca action.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.10-13
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• 1999

For large scale applications of high temperature superconductor(HTS) such as transmission cables, motors and generators, long length of flexible HTS conductors is required. Currently, HTS tape that is capable of being fabricated in long length by industrial processes is the Bi-2223 HTS tape. In this study, we fabricated 19 filamentary Bi-2223($Bi_{1.8}$$Pb_{0.4}$$Sr_{2}$$Ca_{2}$$Cu_{3}$$O_{10+X}$) HTS tape with 100m length by PIT(Powder In Tube) process. Critical current(Ic) of this long length tape was measured 18.5 A at 77 K, self field and short sample Ic is 32.5 A at the same condition. Critical current of 100m length tape was decreased by about 1/3 compared to that of short tape. This was mainly resulted from the increase of non homogeneity in oxide layer.

• Progress in Superconductivity and Cryogenics
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• v.1 no.2
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• pp.15-19
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• 1999

For large scale applications of high temperature superconductor (HTS) such as transmission cables, motors and generators, long length of flexible HTS conductor is required. Currently, Bi-2223 HTS tape is capable of being fabricated in longer than 100 m length by industrial processes. In this study, we fabricated 100 m 19 filamentary Bi-2223 ($Bi_{1.8}Pb_{0.4}Sr_2Ca_2O_{10+x}$) HTS tape by PIT (Power in Tube) process. Critical current(IC) of this long length tape was measured 18.5 A at 77K, self field. Critical current of 100 m length tape was mainly resulted from the increase of inhomogeneity in oxide from the increase of inhomogeneity in oxide layer. Engineering critical current (Je=Ic/total tape cross-section area) that is important factor for practical applications and fabrication cost was measured 2.2 kA/cm2.

• Transactions on Electrical and Electronic Materials
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• v.11 no.3
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• pp.112-115
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• 2010

This paper provides the properties of $TiO_2$ nanotube arrays which are fabricated by anodic oxidation of Ti metal. Highly ordered $TiO_2$ nanotube arrays could be obtained by anodic oxidation of Ti foil in $0.3\;wt{\cdot}%$ $NH_4F$ contained ethylene glycol solution at $30^{\circ}C$. The length, pore size, wall thickness, tube diameter etc. of $TiO_2$ nanotube arrays were analyzed by field emission scanning electron microscopy. Their crystal properties were studied by field emission transmission electron microscopy and X-ray photoelectron spectroscopy.

• Carbon letters
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• v.14 no.3
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• pp.175-179
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• 2013

Isolated single wall carbon nanotubes (SWCNTs) were synthesized by chemical vapor deposition (CVD) using a liquid precursor (xylene) as a carbon source. Transmission electron microscopy (TEM) and atomic force microscopy confirmed the isolated structure of the SWCNTs. Micro-Raman measurements showed a tangential G-band peak ($1590cm^{-1}$) and radial breathing mode (RBM) peaks ($150-240cm^{-1}$). The tube diameters determined from the RBM frequencies are in good agreement with those obtained from TEM. The chirality of the isolated SWCNTs could be determined based on the energy of the laser and their diameter. A further preliminary study on the nitrogen doping of isolated SWCNTs was carried out by the simple use of acetonitrile dissolved in the precusor.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1828-1830
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• 1996

In this study, We developed the optical fiber incorporated high-voltage underground power cable which is combined optical fibers with conventional high-voltage underground power cable. Optical-Unit that optical fiber is inserted in stainless tube is tested, and we got good results enough to safe optical fibers. Also we put the optical fiber incorporated high-voltage underground power cable to the test of electrical characteristics and optical characteristics, we knew that the electrical characteristics were the same characteristics as conventional high-voltage underground power cable and the transmission loss change was almost zero.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.92-98
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• 2012

It is made compulsory to install SPD for the purpose of protecting electric and electronic devices when an abnormal voltage such as lightning occurs to power line using power frequency of 60Hz. Recently, the high speed communication technology utilizing power line is receiving attention again as a communication technology for smart grid. The SPD influences the performances of power line communication when using SPD and power line communication system together. In order to improve the performance of power line communication, a proposed scheme for series connection of gas discharge tube to ZnO varistor was presented. This paper measured the impacts of series connection of GDT to SPD using ZnO varistor on the limit voltage of Class III SPD. This paper also presented the DC operating voltage of GDT which satisfies the limit voltage of power line communication system and SPD simultaneously.