• Journal of KIISE
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• v.41 no.10
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• pp.792-798
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• 2014

In spatial databases, R-tree is one of the most widely used indexing structures and many variants have been proposed for its performance improvement. Among these variants, Hilbert R-tree is a representative method using Hilbert curve to process large amounts of data without high cost split techniques to construct the R-tree. This Hilbert R-tree, however, is hardly applicable to large-scale applications in practice mainly due to high pre-processing costs and slow bulk-load time. To overcome the limitations of Hilbert R-tree, we propose a novel approach for parallelizing Hilbert mapping and thus accelerating bulk-loading of Hilbert R-tree on GPU memory. Hilbert R-tree based on GPU improves bulk-loading performance by applying the inversed-cell method and exploiting parallelism for packing the R-tree structure. Our experimental results show that the proposed scheme is up to 45 times faster compared to the traditional CPU-based bulk-loading schemes.

• Polymer(Korea)
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• v.25 no.3
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• pp.334-342
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• 2001

Gentamicin sulfate (GS)-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) devices were prepared for controlled-release of antibiotics. In this study, the effects of thickness, hydroxyvalerate (HV) content, initial drug-loading ratio, and additive content on the release profile have been investigated. The morphology of devices was examined with scanning electron microscope (SEM) before and after in vitro release; their highly porous surface and cross-sectional were observed. It could be suggested that device would be affected by the packing of the HV and additive content, which would depend on their structure. A high performance liquid chromatography (HPLC) was used to detect and quantify the release of GS from the device. The drug release from all the devices showed biphasic release patterns, and some matrices released the incorporated antibiotic throughout 30 days with a near zero-order release rate. The release patterns were shown to be changed by altering the thickness, copolymer ratio, and additive content.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.80-90
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• 1994

To develop VLSI of higher packing density with 0.5.mu.m gate length of less, semiconductor devices require shallow junction with higher doping concentration. the most common method to form the shallow junction is ion implantation, but in order to remove the implantation induced defect and activate the implanted impurities electrically, ion-implanted Si should be annealed at high temperature. In this annealing, impurities are diffused out and redistributed, creating deep PN junction. These make it more difficult to form the shallow junction. Accordingly, to miimize impurity redistribution, the thermal-budget should be kept minimum, that is. RTA needs to be used. This paper reports results of the diffusion characteristics of PSG film by varying Phosphorus weitht %/ Times and temperatures of RTA. From the SIMS.ASR.4-point probe analysis, it was found that low sheet resistance below 100 .OMEGA./ㅁand shallow junction depths below 0.2.mu.m can be obtained and the surface concentrations are measured by SIMS analysis was shown to range from 2.5*10$^{17}$ aroms/cm$^{3}$~3*10$^{20}$ aroms/cm$^{3}$. By depending on the RTA process of PSG film on Si, LDD-structured nMOSFET was fabricated. The junction depths andthe concentration of n-region were about 0.06.mu.m. 2.5*10$^{17}$ atom/cm$^{-3}$ , 4*10$^{17}$ atoms/cm$^{-3}$ and 8*10$^{17}$ atoms/cm$^{3}$, respectively. As for the electrical characteristics of nMOS with phosphorus junction for n- region formed by RTA, it was found that the characteristics of device were improved. It was shown that the results were mainly due to the reduction of electric field which decreases hot carriers.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.118-118
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• 2000

New single-source precursor, [AlCI3:NH2tBu] was synthesized for AlN thin f film processing with AICI3 (Aluminum Chloride) and tBuNH2 (tert-butylamine). AlN thin films for packaging aspplication were deposited on sapphire substrate by a atmosph하ie-pressure MOCVD. In most of other study methyl-based AI precursors w were used for source, But herein Aluminum Chloride was used for as AI source i in order to prevent the carbon contamination in the films and stabilize the p precursor. New precursor showed the very high gas vapor pressure so it allowed to m make the film under atmospheric-pressure and get the high purified film. High q quality AlN thin film was obtained at 700 to $900^{\circ}C$. The new precursor was p purified by a sublimation technique and help to fabricate high purity film. It s showed high vapor pressure, which is able to a critieal factor for the high purity a and atmospheric CVD of AlN. High Quality AIN thin film was obtained at $700-900^{\circ}C$. The AIN film was characterized by RBS

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.25-31
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• 2016

This paper has analyzed the structure, applicable regulations and the resistance characteristics of insulation ring type of CSST (Corrugated Stainless Steel Tubing for Gas). With the flammability test conducted in accordance with KS C IEC 60811-1-1, the evaluation of insulation resistance, temperature characteristics, and reliability has been conducted. An insulation ring type CSST consists of protective coating, tube, nut, insulation ring, packing, socket, and ball valve. Connecting an insulation ring type CSST to gas tubings for gas appliance is not permitted, moreover, the product shall be installed inside a sleeve pipe in case of buried installation such as the ceiling. Damages on protective coating and tube were detected when fire was applied to the test sample with a portable torch for 60 seconds. The insulation resistance of a normal product was $49.59M{\Omega}$, while that of the product completed the flammability test reduced to $9.21M{\Omega}$. The mean insulation resistance within the confidence Interval of 95% using the mini tap program 17 was $49.59M{\Omega}$ and the mean insulation resistance within the confidence interval reduced to $9.21M{\Omega}$. In the normal distribution analysis of 95% confidence interval, the value-P of the normal product was stable at 0.075 and AD(Anderson-Darling) statistic value was turned out to be 0.063, which is very normal, and the standard deviation was analyzed as 0.2586. The value P of the product completed the flammability test resulted in 0.005, the AD was 1.355 and the standard deviation reduced to 0.07908.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.1-8
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• 2012

The effects of several factors including organic pigment blending and calending conditions on the surface and optical properties of coated paper were investigated. When clay and calcium carbonate are blended in the ratio of 7 to 3, highest smoothness and relative sediment volume were obtained. When organic pigments were added to the mixture of clay and calcium carbonate, the relative sediment volume did not changed significantly. However, when organic pigments were added to calcium carbonate, sheet gloss and smoothness were improved, and showed the better results than that obtained from the mixture of organic pigment and clay. When organic pigment is blended with clay, the particles of organic pigment are buried in the packing structure of coating layer. However, the particle shape of calcium carbonate is quite different from that of clay, and the aspect ratio of calcium carbonate is similar to that of organic pigment. Thus organic pigment particles are not buried and improved effectively the physical characteristics of coating layer. When the hollow sphere pigment was blended, opacity and sheet gloss were improved significantly. Even though the coating color applied was reduced, the similar level of opacity was maintained. Also, if particle size and void volume are increased, gloss is improved, because coating layer is easily transformed in calendering. Therefore, even though lower pressure was applied during calendering, the smoothness of surface of coating layer was improved, and the decrease of void volume in coating layer was reduced, and the quality of coated sheet can be improved.

• Fire Science and Engineering
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• v.30 no.3
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• pp.23-30
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• 2016

A fire extinguishing system for a rack warehouse was recently designed, which only consider the gross area and number of stories. However, the design of such a system should take into account not only the planar structuree, but also the elevation perspectives due to its vertical structure. Moreover, the fire load of the commodities palletized on the racks should be considered, in order to design a performance-based fire safety system that is appropriate for these environmental conditions. For this reason, this study analyzed the fire characteristics of the commodities palletized on the racks (pallet + the commodities in a box unit + vinyl packing material), taking into consideration the results of a field investigation conducted in Korea, as well as the Hazard Classifications of Commodities used in other countries. Through this analysis, the heat release rate (HRR) and smoke production rate (SPR) were derived.

• Journal of the Korean institute of surface engineering
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• v.45 no.6
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• pp.248-256
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• 2012

A Pd-based hydrogen membranes for hydrogen purification and separation need high hydrogen perm-selectivity. The surface roughness of the support is important to coat the pinholes free and thin-film membrane over it. Also, The pinholes drastically decreased the hydrogen perm-selectivity of the Pd-based composite membrane. In order to remove the pinholes, we introduced various surface pre-treatment such as alumina powder packing, nickel electro-plating and micro-polishing pre-treatment. Especially, the micro-polishing pretreatment was very effective in roughness leveling off the surface of the porous nickel support, and it almost completely plugged the pores. Fine Ni particles filled surface pinholes with could form open structure at the interface of Pd alloy coating and Ni support by their diffusion to the membrane and resintering. In this study, a $4{\mu}m$ surface pore-free Pd-Cu-Ni ternary alloy membrane on a porous nickel substrate was successfully prepared by micro-polishing, high temperature sputtering and Cu-reflow process. And $H_2$ permeation and $N_2$ leak tests showed that the Pd-Cu-Ni ternary alloy hydrogen membrane achieved both high permeability of $13.2ml{\cdot}cm^{-2}{\cdot}min^{-1}{\cdot}atm^{-1}$ permation flux and infinite selectivity.

• Fire Science and Engineering
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• v.24 no.3
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• pp.72-77
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• 2010

Honeycomb core structure with its excellent stiffness and strength is being utilized in many fields such as interior building material. Because it is inexpensive and renewable, honeycomb paper production is economically and environmentally helpful. However, the paper needs to be fireproofed because it is vulnerable to fire. In this study, we have undergone the performance evaluation process of the honeycomb paper which is widely used as interior material of a fire door and packing material. Four kinds of honeycomb (a honeycomb made of flame-resistant paper; a honeycomb attached with conventional flame-resistant film made in the laboratory; honeycomb impregnated with flame retardant; a honeycomb attached with flame-resistant film after impregnating fire retardant) were used in the study to compare the fire retardant performance. As a result, the honeycomb with impregnated flame retardant showed the highest performance. The flame-resistant film was effective in delaying the igniting time but had a negative effect on the rate of heat and smoke production.

• Journal of the Korean Geosynthetics Society
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• v.2 no.1
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• pp.47-55
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• 2003

The effects of fiber composition factors of 14 geotextiles which are thickness, porosity, fiber length and diameter etc. on the transmissivity were examined and in-plane permeability of geotextiles under thickness change, transmissivity, confined load were analyzed by the constitutive equations. And the effects of laminar structure on the permittivity of laminar geotextile composites which were manufactured with fiber packing densities were assessed. Transmissivities were increased with thickness of geotextiles and in-plane permeability coefficients were increased with porosity and fiber diameter. The effects of porosity were decreased with normal stress and slightly increased with fiber length. Transmissivities were increased with fiber diameter and showed same tendensy for the same fiber length. Permittivities of laminar geotextile composites were influenced by the waterhead loss in the inner interface and the connection shape of these composites to water path was interpreted as bell mouth type or soft flux pipe type.