• Applied Microscopy
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• v.23 no.1
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• pp.35-55
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• 1993

cis-Dichlorodiammineplatinum (II) (cis-Platin), a metallic compound, has widely been used as an effective anticancer chemotherapeutic agent. The precise mechanism of action of this agent is still unknown, but it is postulated that cis-Platin may act on the cancer cell like bifunctional alkylating agents. Although this agent is very beneficial to the patients with cervical cancer, germinoma of testis, neuroblastoma and others, it may also damage to the normal cell so that many side effects; severe hemorrhagic enterocolitis, bone marrow depression, renal damage and liver damage will develope. This experiment has been undertaken to pursue the cytotoxic effects of the cis-Platin on the ultrastructures of the interalveolar septum in the mouse lung. A total of 55 healthy male mice of ICR strain were used as experimental animals and divided into 5 mice of normal control group and 50 mice of cis-Platin treated group. The mice of cis-Platin treated group were sacrificed by carotid exsanguination at 6, 12, 24 hours, 3 days and 7 days after intraperitoneal injection of 6.0 mg of cis-Platin ($Abiplatin^R$ Abic Co. Ltd.) per kg of mouse body weight. The specimen obtained from the lower lobe of left lung were sliced into $1mm^3$ and prefixed with 2% glutaraldehyde -2.5% paraformaldehyde solution prepared with Millonig's phosphatae buffer solution (pH 7.4) at $4^{\circ}C$ for 3-4 hours. After postfixation with 1% osmium tetroxide solution all specimens were embedded in Epon 812. Ultrathin sections about $600-800{\AA}$ in thickness were stained with uranyl acetate and lead citrate and observed with Hitachi-600 electron microscope. The results obtained were as follows: 1. Local swellings with increase of electron density and number of pinocytic vesicles in the cytoplasms of the type I pneumocyte and endothelial cell of the blood air barrier in interalveolar septum of cis-platin treated mice were observed. 2. Cisternae of rough endoplasmic reticulum were dilated and sacculated in association with detachment of membrane bound ribosomes of the type II pneumocyte in interalveolar septum of cis-Platin treated mice. 3. Swollon mitochondria with uneven electron density of their matrix were observed in the type II pneumocyte of interalveolar septum in the cis-Platin treated mice. 4. The lamellae of lammelar bodies in type II pneumocyte of interalveolar septum in cis-Platin treated mice were devoided or transformed into homogeneous electron dense material. It is consequently suggested that cis-Platin would induce the cellular edema of type I pneumocyte and endothelial cell, and degenerative changes of cytoplasmic organelles of the type II pneumocyte in the interalveolar septum of the mouse lung.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.25-31
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• 2008

Cp-Ti and Ti-6Al-4V alloys commonly used dental implant materials, particularly for orthopaedic and osteosynthesis because of its suitable mechanical properties and excellent biocompatibility. This alloys have excellent corrosion behavior in the clinical environment. The first factor to decide the success of dental implantation is sufficient osseointegration and high corrosion resistance between on implant fixture and its surrounding bone tissue. In this study, in order to increase corrosion resistance and biocompatibility of Cp-Ti and Ti-6Al-4V alloy that surface of manufactured alloy was coated with TiN by RF-magnetron sputtering method. The electrochemical behavior of TiN coated Cp-Ti and Ti-6Al-4V alloy were investigated using potentiodynamic (EG&G Co, PARSTAT 2273. USA) and potentiostatic test (250mV) in 0.9% NaCl solution at 36.5 $\pm$ 1$^{\circ}C$. These results are as follows : 1. From the microstructure analysis, Cp-Ti showed the acicular structure of $\alpha$-phase and Ti-6Al-4V showed the micro-acicular structure of ${\alpha}+{\beta}$ phase. 2. From the potentiodynamic test, Ecorr value of Cp-Ti and Ti-6Al-4V alloys showed -702.48mV and -319.87mV, respectively. Ti-6Al-4V alloy value was higher than Cp-Ti alloy. 3. From the analysis of TiN and coated layer, TIN coated surface showed columnar structure with 800 nm thickness. 4. The corrosion resistance of TiN coated Cp-Ti and Ti-6Al-4V alloys were higher than those of the non-coated Ti alloys in 0.9% NaCl solution from potentiodynamic test, indicating better protective effect. 5. The passivation current density of TiN coated Cp-Ti and Ti-6Al-4V alloys were smaller than that of the noncoated implant fixture in 0.9% NaCl solution, indicating the good protective effect resulting from more compact and homogeneous layer formation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.238-246
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• 1996

High-density SiC-AIN solid solutions were fabricated from powder mixtures of $\beta$-SiC and AIN by hot-pressing in the 1870 to $2030^{\circ}C$ temperature range. The reaction of AIN and $\beta$-SiC (3C) powder transformed to the 2 H (wurzite) structure appeared to depend on the temperature and SiC/A1N ratio and seeds present. The crystalline phases consisted of a SiC-rich solid-solution phase and an A1N-rich solid-solution phase. At $2030^{\circ}C$ for 1 h, for a composition of 50 % AIN/50 % SiC with a seeding of $\alpha$-SiC, the complete solid solution could be obtained and the microstructures are equiaxed with a relatively homogeneous grain size of 2 H phases. The variation of the seeding of $\alpha$-SiC in SIC-A1N solid solutions could be attributed to the transformation behaviour and differences in size and shape of the grains, as well as to other factors, such as grain size distributions, compositional inhomogeneity, and structural defects.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.597-608
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• 1994

A new process for the production of high purity ${\alpha}-Al_2O_3$ from ammonium aluminium sulfate solution abtained through the sulfation of low grade bauxite ore with $(NH_4)_2SO_4$, and leaching of the sulfated product was investigated. This process is consisted of solvent extraction for Fe component removal from ammonium aluminum sulfate solution and homogeneous precipitation of Al containing precipitate from the refined ammonium aluminium sulfate solution by using urea as precipitator. The optimum conditions of solvent extraction with Alamine 336 as extractant were shaking time of 4min, organic phase ratio to aqueous phase of 0.25. The types of precipitation products from this precipitation were amorphous alumina gel, pseudo-boehmite and crystalline boehmite in the lower temperature of $100^{\circ}C$, in the range from $125^{\circ}C$ to $150^{\circ}C$, and above $150^{\circ}C$, respectively. And also amorphous alumina gel hydrate in $1000^{\circ}C$ and crystalline boehmite in $1250^{\circ}C$ were tranfered to ${\alpha}-Al_2O_3$, respectively. This alumina was identified as ${\alpha}-Al_2O_3$ of purity 99.7%.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.649-656
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• 2002

In situ patterned zinc oxide thin films were prepared by precipitation of Zn(NO$_3$)$_2$ aqueous solution containing urea and by microcontact printing using Self-Assembled Monolayers(SAMs) on A1/SiO$_2$/Si substrates. The visible precipitation of Zn(OH)$_2$ that was formed in the Zn(NO$_3$)$_2$ aqueous solution containing urea was enhanced with an increase of the reaction temperature and the amount of urea. As the reaction time of Zn(NO$_3$)$_2$ with urea was prolonged, the thickness and grain size of Zn(OH)$_2$ thin layers were increased, respectively. The optimum precipitation condition was at 80$\^{C}$ for 1 h for the solution with the ratio of Zn(NO$_3$)$_2$ to urea of 1 : 8. Homogeneous ZnO thin films were fabricated by the heat treatment of 600$\^{C}$ for 1 h of Zn(OH)$_2$ precipitation on Al/SiO$_2$/Si substrate. This was available to the in-situ patterned ZnO thin films with uniform grain size. Hydrophobic SAM, Octadecylphosphonic Acid(OPA) and hydrophilic SAM, 2-Carboxyethylphosphonic Acid(CPA) were applied on the Al/SiO$_2$/Si substrate by microcontact printing method. In situ patterned ZnO thin film was successfully prepared by the heat treatment of Zn(OH)$_2$ precipitated on the surface of hydrophilic SAM, CPA.

• Membrane Journal
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• v.6 no.3
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• pp.157-165
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• 1996

Polysulfone(PS) membranes were prepared from homogeneous PS solutions by the phase inversion technique. When propionic acid(PA) was added into a casting solution of n-methylpyrrolidone(NMP) and PS, precipitation rate of the solution film was accelerated. This kind of acceleration was consistent, even though a precipitating nonsolvent was changed from water to isopropanol. These phenomena were caused by decrease of nonsolvent tolerance in the casting solution due to addition of PA. PS powder was prepared by precipitation of a 3wt% solution in dimethylformamide(DMF) using ethanol as nonsolvent. Gas adsorption analysis of the powder showed that the capillary condensation sites were found in the powder structure. Membranes prepared from PS solution(15wt%) in NMP had the following characteristics of gas adsorption and water permeation. In gas adsorption analysis, the membrane precipitated using isopropanol showed low uptake of nitrogen gas and the capillary condensation sites were not found. On the contrary, a significant amount of the capillary condensation sites was found in the membrane coagulated by water, which was related to increase of nitrogen uptake. tn the membrane prepared froin the solution including PA, an increase of the Henry's law sites and the Langmuir sites was not found clearly. However, the capillary condensation sites were significantly increased, and the water transport also increased.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.331-344
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• 2009

Buffalograss is an important turfgrass species with excellent cold, heat, and drought tolerance. Understanding the physiological integration of buffalograss under heterogeneous conditions helps to develop cultural practices that better use limited resources for uniform turf quality. The objective of this study was to evaluate physiological integration of buffalograss under water deficit stress and the involvement of lipid peroxidation and antioxidants in the process. In one experiment, buffalograss was planted in the center of a four-compartment growth unit. Watering frequencies, once a week(+) and once in two weeks(-), were combined with the sand(S) or peat(P) in each unit to generate five total treatments(P+S-P-S+, P+P+P+P+, S-S-S-S-, P-P-P-P-, and S+S+S+S+). The average number of shoot established from the heterogeneous root-zone medium was higher than the average of four possible homogeneous media. In second experiment, single ramet in Hoagland solution($S_0$) or single ramet in Hoagland solution with 20% PEG-6000($S_s$) were compared with two connectedramets under different treatments. Treatments for connected ramets were young ramet in Hoagland solution($Y_{os}$) and old ramet in Hoagland solution with 20% PEG-6000($O_{os}$), and old ramet in Hoagland solution($O_{ys}$) and young ramet in Hoagland solution with 20% PEG-6000($Y_{ys}$). Lipid peroxidation, antioxidants, and proline showedphysiological integration between ramets subjected to different levels of water stress. Superoxide dismutase(SOD), Guaiacol peroxidase(G-POD), malondialdehyde(MDA), and free proline also showed different time courses and relative activities during the physiological integration.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.3
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• pp.463-467
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• 1998

The microstructure evolution during mechanical alloying (MA) of Nb and Sn powder; of average composition $Nb_3Sn$, has been investigated by X-ray diffraction (XRD). The structural development with milling time depends on the ball size for a given powder/ball ratio. Using a larger ball of 9.5 mm diameter, the elemental powders initially alloy mechanically to form an A15 structure phase, and then amorphized with continued milling. However, in case of milling with a smaller ball of 3.968 mm diameter, an amorphous phase is first formed. These results can be understood by considering the dependence of the milling energy on the ball size. The homogeneous stoichiometric $Nb_3Sn$ phase could be easily obtained by heat treatment of supersaturated solid solution produced by MA. Heat treatment of an amorphous formed by MA resulted in the mixture of the $Nb_3Sn$ and $Nb_6Sn_5$phases.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.4
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• pp.151-155
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• 2007

Quasi-phase-matched (QPM) second harmonic generation (SHG) waveguide devices for a green light generation were fabricated by a periodically patterned electrode on the +Z crystal surface and homogeneous LiCl solution using a 5 mol% MgO doped congruent z-cut lithium niobate crystals. Using selective chemical etching, we confirmed the periodic (${\sim}6.8{\mu}m$) domain inverted structure and measured SHG properties of fabricated periodically poled MgO : $LiNbO_3$ ridge-type waveguides.

• Carbon letters
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• v.24
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• pp.90-96
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• 2017

We demonstrated the sensitivity of optically active single-walled carbon nanotubes (SWCNTs) with a diameter below 1 nm that were homogeneously dispersed in cement composites under a mechanical load. Deoxyribonucleic acid (DNA) was selected as the dispersing agent to achieve a homogeneous dispersion of SWCNTs in an aqueous solution, and the dispersion state of the SWCNTs were characterized using various optical tools. It was found that the addition of a large amount of DNA prohibited the structural evolution of calcium hydroxide and calcium silicate hydrate. Based on the in-situ Raman and X-ray diffraction studies, it was evident that hydrophilic functional groups within the DNA strongly retarded the hydration reaction. The optimum amount of DNA with respect to the cement was found to be 0.05 wt%. The strong Raman signals coming from the SWCNTs entrapped in the cement composites enabled us to understand their dispersion state within the cement as well as their interfacial interaction. The G and G' bands of the SWCNTs sensitively varied under mechanical compression. Our results indicate that an extremely small amount of SWCNTs can be used as an optical strain sensor if they are homogeneously dispersed within cement composites.