• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.1-15
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• 1996

In this paper, the preparation of lead zirconium titanate(PZT) thin film by sol-gel processing was descried. Thin film coated with thickness of 4${\mu}{\textrm}{m}$ on the stainless steel substrates using the multiple spin-coating process. The crystalline phases of PZT powder and film were investigated by X-ray diffraction pattern and PZT thin film has perovskite structure over 600 C annealing temperature. Corona charging characteristics of the ferroelectric PZT thin film at 600 C were investigated by electrophotographic measurement. A difference in the charging characteristics between positive and negative corona charging was found. The charge acceptance depended in the polarity of corona and the poling of film. According to the D-E hysteresis measurment, PZT thin film can be poled by corona charging without use of top electrode. The remnant polarization in the PZT thin film is generally in the order of 48$\mu$C/$\textrm{cm}^2$. From this results, the ferroelectric PZT thin film will be possible to apply for the add-on type imaging formation.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.101-104
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• 1995

In this paper, we designed a cascade adaptive filter for elimination of the baseline drift and the distortion of the filtered signal. The cascade adaptive filter(CAF) consists of two filters. The first adaptive filter which has the cutoff frequency of 0.3Hz eliminate the noisy signal. The second adaptive filter remove the remnant baseline drift which is not eliminated by the first adaptive filter. Comparing the performance of the CAF with standard filter, recursive notch filter(RNF) and a adaptive impulse correlated filter(AICF), the CAF showed a higher performance in removal of the baseline drift than standard filler, and RNF. Also, considering the distortion of filtered signal, CAF is better than AICF and is comparable to the standard filter.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.152-155
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• 2012

A Rathke's cleft cyst (RCC) is a benign pituitary cyst derived from the remnant of Rathke's pouch, and usually presents as an intrasellar lesion with varying degrees of suprasellar extension. However, to date, a description of a primary prepontine RCC with no intrasellar component has not been reported. The author describes an exceptional case of a symptomatic RCC located behind the sella turcica in a 41-year-old woman who presented with severe headache. The author also provides an embryological hypothesis of the development of an ectopic RCC, with a special emphasis on radiologic characteristics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.330-334
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• 1999

This paper presents a new transient voltage blocking device (TBD) for commucation facilities with low power and high frequency bandwidth. Conventional protection devices have some problems such as low frequency bandwidth, low energy capacity and high remnant voltage. In order to improve these limitations, the new TBD, which consists of a gas tube, avalanche diodes and junction type field effect transistors (JFETs), was designed and fabricated JFETs were used as an active non-linear element and a high speed switching diode with low capacitance limits high current. Therefore the avalanche diodes with low energy capacity are protected from the high current, and the TBD has a very small input capacitance. From the performance test using surge generator, which can produce 1.2/50${\mu}\textrm{s}$ 4.2 k$V_{max}$, 8/20${\mu}\textrm{s}$ 2.1 kA$\sub$max/, it is confirmed that the proposed TBD has an excellent protection performance in tight clamping voltage and limiting current characteristics.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.200-205
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• 1999

In the ferromagnetic phase with electrons for La$_{1-x}$(Ca or Sr)$_x$MnO$_3$, films, a remnant resistivity of the order of 10$^{-8}$ ${\omega}$m is observed up to 100 K and increases exponentially with temperature up to T$_c$ and above one Tesla as a function of magnetic field strength (a positive magnetoresistivity). The phase below T$_c$ is regarded as a polaronic state with a polaronic tunneling conduction. Possible p-wave condensation (or superconductor) with a parabolic density of states and the phase separation are discussed on the basis of the two-fold degeneracy of ${\varrho}_{\delta}$ orbitals.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.752-756
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• 2002

Variable weld bead penetrations related to the base metal chemistry of stainless steels in GTA welding have been under constant investigations due to their industrial implications. It has been proposed that among other elements, the sulfur content of steels determines the weld pool geometry, particularly its penetration. It is suggested that the surface tension temperature gradient of steels becomes positive with appropriate dosing in sulfur and results in inward melt flow, propitious for deeper welds. However, the chemistry of industrial steels is complex due to the presence of multiple minor elements either deliberately added or remnant impurity traces. With this in view, investigations on 41 austenitic and nine martensitic stainless steels were carried to see if there existed any possible relation between the weld profile and some of the designated elements. The results suggest no direct correlation between sulfur or any other major or trace element and weld penetration. At first glance the results are contradictory to what is often asserted.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2006.05a
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• pp.119-119
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• 2006

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.469-474
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• 2002

Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bumps reflowed by laser was superior than the solder bumps reflowed by hot air, and the microstructure inside the solder bumps reflowed by laser was much finer. Analysis on interfacial reaction showed that eutectic solder reacted with Au/Ni/Cu pad shortly after the solder was melted. Interface of solder bump reflowed by laser consists of a continuous AuSn$_4$ layer and remnant Au element. Needle-like AuSn$_4$ grew sidewise from interface, and then spread out to the entire interface region. A thin layer of Ni$_3$Sn$_4$ intermetallic compound was found at the interface of solder bump reflowed by hot air, AuSn$_4$ particles distributed inside the whole solder bump randomly. It is the combination effect of the continuous AuSn$_4$ layer and finer eutectic microstructure inside the solder bump reflowed by laser that resulted in higher shear strength.

• Tribology and Lubricants
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• v.12 no.3
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• pp.39-47
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• 1996

The magnetic fibrous polymeric oil filter elements for industrial lub-systems were obtained by pneumoextrusion processing prepared from thermoplastic pqlymer (polyamide) containing a magnetic particulate filler (Ba ferrite), and treated subsequently in a magnetic fields. Using the standard laboratory oil filtration test rig, metallic particle quantifier and image analyser system, the dependence of filtration charateristics of the magnetic filter media on the parameters of porosity and magnetic properties was investigated. The pressure drops and efficiencies of lubricating filter elements were measured on the packing density and magnetised filler content of filter element. Also, the industrial lub-systems such as lubricant filters for gear test rig and electric discharge processing machine were used for testing the flitrational characteristics of tl, c magnetised filter elements. The magnetic fibrous polymeric filter material was shown to possess a highly filtration efficiency in filtering the fine ferrous particles with increasing the magnetic force of filter element. Therefore, it is expected that the magnetic fibrous polymeric filter material should be used for effective oil filrers on the industrial lub-systems.

• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.13-22
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• 1990

Nangmyun-broth was collected as samples from 25 common restaurants in Bucheon to examine it's sanitary condition. The main course of bacterial contamination was persuited for it's sanitary improvement. Bacterial count in summer sample was not greatly different from that in winter, resulting in total count 1.7$\times$10i1m1, lactic acid bacteria 8.7$\times$106/ml, coliform group 1 2$\times$105/ml, Staphylococcus aureus 6.5$\times$102/ml. Bacterial contamination occurred remarkably with the use of storage barrel in which remnent Nangmyun-broth was still resting, because the remnant Nangmyun-broth contained high level of bacteria Good santary condition in Nangmyun-broth was obtained by the use of clean barrel which had been washed with tap water or sterilizied with steam before filling fresh Nangmyun -broth for cold storage. The growth of Escherichia coli and Staphylococcus aureus was inhibited in the presence of acetic acid(0.01~0.05%) or mustart(0.1~0.5%)