• Economic and Environmental Geology
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• v.26 no.3
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• pp.289-309
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• 1993

Milyang pyrophyllite deposit which was formed by hydrothermal alteration occurs in Late Cretaceous andesitic tuff in the Milyang area, Gyeongsangnamdo. The wall rock alteration and genesis of the Milyang pyrophyllite deposit were studied. The ore minerals are composed dominantly of pyrophyllite accompanied by small amounts of quartz, kaolinite, pyrite, dumortierite and diaspore. The alteration halo of this deposit can be divided into three zones on the basis of mineral assemblage; pyrophyllite, sericite and chlorite zone. The common mineral assemblages of each alteration zone are as follows: (1) pyrophyllite zone; pyrophyllite-quartz-kaolinite-pyrite-dumortierite-diaspore, (2) sericite zone; sericite-quartz-pyrite-kaolinite, and (3) chlorite zone; chlorite-plagioclase-quartz. Major element chemistry shows that characteristic depletion in MgO, CaO, and $Na_2O$ and relative increase in FeO from less altered chlorite zone to extensively altered pyrophyllite zone corresponding to variation in mineral assemblages. The paragenesis of ore minerals, oxygen isotope data, chlorite and illite geothermometry suggest that ore deposit was formed at about $250{\sim}330^{\circ}C$. Both hydrogen and silica activities are high in pyrophyllite zone. Potassium activity increases in sericite zone while hydrogen activity becomes low in chlorite zone. The pyrophyllite zone was formed relatively higher temperature than those of sericite and chlorite zones. The ore fluid was considered to be magmatic water in origin derived from the residual granitic magma which interacted with meteoric water.

• Journal of Korean Foot and Ankle Society
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• v.19 no.2
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• pp.63-68
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• 2015

Purpose: The purpose of this study was to report impacts of the amount of displacement of percutaneous osteotomy on the clinical and radiologic results in the treatment of bunionette deformities. Materials and Methods: We retrospectively reviewed 36 cases of bunionette deformities treated with percutaneous modified Kramer osteotomies from 2009 to 2013. We measured amounts of displacement on anteroposterior and lateral plain radiographs as well as multiple parameters which represent degrees of the bunionette deformities. We also recorded radiological healing time, clinical healing time, residual symptoms, and the time of returning to daily activity. Results: No meaningful correlation was found between severity of preoperative deformity and amount of displacement of the osteotomy. The amount of displacement on a horizontal plane did not affect the healing time, duration of symptoms, or time of returning to daily activity. However, large sagittal displacement was related to duration of postoperative symptoms. Conclusion: Findings of this study suggest that the displacement in percutaneous osteotomy for bunionette deformity does not affect clinical results and healing time. We believe that we do not need to be excessively cautious about how large the displacement we make during the percutaneous modified Kramer osteotomy for the bunionette deformity.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.219-227
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• 2009

In H.264/AVC, if each block is quantized with a adaptive quantization parameter(QP) regardless of the characteristics of a block, it could be the deterioration of the picture quality. In this paper, an adaptive block-based QP selection method is proposed in order to improve picture quality by utilizing the bit amounts of the zigzag-scanned integer transform coefficients of the neighboring blocks and changing the QP value in the current block. The proposed method works in the same way as the encoder and decoder without transmitting the change of QP value to the decoder side. The experimental results show that the proposed method achieves a gain of about $0.1\sim0.3dB$ compared with H.264/AVC.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.169-174
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• 2006

A distinctive difference of hydrocarbon in crude oil and petroleum products exists. Depending on the origin where it comes from, crude oil shows its own unique pattern which is different from petroleum products containing characteristics according to their operating process and production period. A process of mixing behavior in a tank containing residual amounts of oil draws its own pattern when analysis is conducted. The analytical process described above is named oil fingerprint method. This study investigates an effectiveness of the method for comparing data sets produced by conventional gas chromatography with mass spectrometer (GC/MS) and comprehensive two-dimensional gas chromatography (GC X GC) which is known as powerful new technology for chemical analysis.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.239-244
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• 1999

aluminum sulfate (alum) as a representative retention aid in papermaking processes was added to pulp suspensions, and the aluminum components adsorbed on the pulp were investigated quantitatively by two types of X-ray elementary analyses with regard to simultaneous changes of their surface charges. X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence analysis (XFA) were applied to determine the aluminum components retained in pulp pads up to ca. 10 nm and 100${\mu}$m depth, respectively. In other words, XPS was utilized to analyze the outermost surface layers of the samples, and XFA was available for measurement of their extensive regions. A particle charge detector (PCD) was used to monitor streaming potentials at various pHs of the pulp mixtures under moderate sharing conditions. At pH 4.5 of pulp suspensions containing alum, surface charges of pulp fibers varied from negative to slight negative (approximately neutral) according to adsorption of aluminum components onto the pulp fibers. Subsequently, when a dilute NaOH solution in limited amounts was added to pulp mixtures, both streaming potentials and surface aluminum content of the pulp fibers increased distinctly although little total aluminum retention increased. Further addition of alkali solutions brought drastic decreases of the surface charges and surface aluminum content, while total aluminum content, on the contrary, increased gradually under neutral conditions. These results indicate that residual aluminum ions remained in pulp suspensions are predominantly adsorbed on surfaces of pulp fibers by adequate alkali additions and they must sufficiently cationize the fiber surfaces with increases of somewhat cationic aluminum complexes formed on the surfaces. On the other hand, aluminum components formed in higher pH ranges have nearly no contribution to improvement of charge properties of the pulp fiber surfaces, even though aluminum retention in pulp pads increases. XPS and XFA analyses combined with streaming potential measurement using a PCD suggest close relationships between aluminum content on the pulp fiber surfaces and their charge properties.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.111-116
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• 2006

The microstickes control effects of some fixing agents, including an inorganic PAC, an organic polyamine (PA) and polydiallydimethyl ammonium chloride (Pdadmac), and a high cationic starch (HCS), were investigated, together with their effects on wet end performances and physical properties of handsheets. Despite that the HCS and Pdadmac had lower cationic charge densities than the PA and PAC (the HCS being even lower), they gave higher zeta potentials to fibers, and lower turbidities, cationic demands and residual COD contents to the pulp liquid phases than the PA and PAC did. In all cases, the HCS showed even better effects than the Pdadmac. In addition, drainage speed was also much higher by the HCS treatments although paper formation was worsened. All the phenomena showed that the HCS can fix more dissolved and colloidal substances to cellulose fibers, indicating that the HCS functioned mainly with flocculation and even hydrogen bonding mechanisms. Data on optical properties further indicated that the HCS interacted preferentially with colloidal substances, since it fixed more 'dirty' microstickes to fibers which decreased more sheet brightness while increasing more sheet opacity (with both higher light absorption and scattering coefficients). Interestingly, the organic fixing agents did not decrease tensile, tearing, and folding strengths of paper sheets made from 100% recycled newsprint pulp, except when they were dosed in high amounts. On the contrary, the inorganic PAC had more serious negative effects on the strength properties, especially on folding endurance. The study suggested that proper use of the HCS can lead to better microstickies control effects than traditional agents and methods.

• 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 Periodontal and Implant Science
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• v.47 no.6
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• pp.388-401
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• 2017

Purpose: The physicochemical properties of a xenograft are very important because they strongly influence the bone regeneration capabilities of the graft material. Even though porcine xenografts have many advantages, only a few porcine xenografts are commercially available, and most of their physicochemical characteristics have yet to be reported. Thus, in this work we aimed to investigate the physicochemical characteristics of a porcine bone grafting material and compare them with those of 2 commercially available bovine xenografts to assess the potential of xenogenic porcine bone graft materials for dental applications. Methods: We used various characterization techniques, such as scanning electron microscopy, the Brunauer-Emmett-Teller adsorption method, atomic force microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and others, to compare the physicochemical properties of xenografts of different origins. Results: The porcine bone grafting material had relatively high porosity (78.4%) and a large average specific surface area (SSA; $69.9m^2/g$), with high surface roughness (10-point average roughness, $4.47{\mu}m$) and sub-100-nm hydroxyapatite crystals on the surface. Moreover, this material presented a significant fraction of sub-100-nm pores, with negligible amounts of residual organic substances. Apart from some minor differences, the overall characteristics of the porcine bone grafting material were very similar to those of one of the bovine bone grafting material. However, many of these morphostructural properties were significantly different from the other bovine bone grafting material, which exhibited relatively smooth surface morphology with a porosity of 62.0% and an average SSA of $0.5m^2/g$. Conclusions: Considering that both bovine bone grafting materials have been successfully used in oral surgery applications in the last few decades, this work shows that the porcinederived grafting material possesses most of the key physiochemical characteristics required for its application as a highly efficient xenograft material for bone replacement.

• Korean Journal of Materials Research
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• v.27 no.2
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• pp.76-81
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• 2017

Recently, there have been many efforts to establish suitable processes for recycling fly ash, which is produced in thermal power plants and which poses serious environmental problems. Use of fly ash as a major ingredient of ceramic tiles can increase fly ash utilization, as well as reduce the cost of raw materials in ceramic tile production. In this study, the effects of fly ash addition on ceramic tile properties such as bending strength, water absorption and porosity were investigated. A manufacturing process of ceramic tile was developed for utilization of fly ash with high carbon content. In this approach, it is important to hold the ceramic tiles at a temperature that is sufficient for carbon oxidation, before the pores supplying oxygen to the inside of the ceramic tile are sealed. Ceramic wall tiles were manufactured with 0-40wt% of fly ash addition. The water absorption and porosity of the fired body were slightly changed with increasing fly ash content up to 30wt% and decreased with greater amounts of fly ash addition. The bending strength of ceramic tile including 10wt% fly ash increased, reaching a level comparable to that of ceramic tile without fly ash.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.1
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• pp.1-11
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• 2000

The hybrid coding algorithm for multi-spectral image obtained from satellite is discussed. As the spatial and spectral resolution of satellite image are rapidly increasing, there are enormous amounts of data to be processed for computer processing and data transmission. Therefore an efficient coding algorithm is essential for multi-spectral image processing. In this paper, VQ(vector quantization), quadtree decomposition, and DCT(discrete cosine transform) are combined to compress the multi-spectral image. VQ is employed for predictive coding by using the fact that each band of multi-spectral image has the same spatial feature, and DCT is for the compression of residual image. Moreover, the image is decomposed into quadtree structure in order to allocate the data bit according to the information content within the image block to improve the coding efficiency. Computer simulation on Landsat TM image shows the validity of the proposed coding algorithm.