• The Journal of Engineering Geology
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• v.27 no.4
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• pp.475-487
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• 2017

We performed landslide flume tests to analyze characteristics of landslide occurrence and change in the ground materials due to rainfall infiltration. The test apparatus is composed of flume, rainfall simulator, and measurement sensors and landslides were triggered by heavy rainfall (Intensity=200 mm/hr) sprinkled at the above of an artificial slope. The measurement sensors for matric suction and volumetric water content were installed with 3 sets at shallow (GL-0.2 m), middle (GL-0.4 m), and deep depth (GL-0.6 m) in the slope and the tests were performed with in-situ, loose, and dense condition of each weathered soils of granite, gneiss, and mudstone. The analyses show that surface erosion was dominant in initial time of the test due to heavy rainfall and then landslides occur following locally happened transverse tension cracks. The characteristics of landslide were both shallow failure because of a spread of wetting front induced by the rainfall infiltration and retrogressive failure. While the matric suction was decreased rapidly without any precursor in the soil saturation, the volumetric water content was increased gradually, reached its maximum value, and then decreased rapidly with landslide.

• Progress in Superconductivity
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• v.6 no.1
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• pp.74-78
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• 2004

YBCO coated conductor is one of the most promising materials as a new generations wire especially for practical power applications. In this work, $YBa_2$$Cu_3$$O_{7}$ -$\delta$/(YBCO) coated conductors (CC) were deposited by pulsed laser deposition (PLD) from buffer layers to superconducting layer on hi-axially textured metal tape. The oxide multilayer buffered substrate of architectures of $CeO_2$/$YSZ/Y_2$$O_3$ was fabricated by PLD at steady status. Then YBCO layer was deposited on RABiTS substrate by stationary and reel-to-reel (R2R) continuous process and we compared with deposition conditions of both processes. The degree of texture of each layer was investigated using X-ray diffraction including $\theta$-2$\theta$ scans, $\omega$-scans and $\Phi$-scans analysis. Their surface morphology was observed by scanning electron microscopy (SEM). The FWHM of the X-ray $\Phi$-scans and $\Phi$-scans indicated that YBCO and buffer layers closely replicate the in-plane and out-of-plane texture of metal tape. Critical current (Ic) at 77 K, self-field of 75.8 A/cm-width, critical temperature (Tc) of 85 K, and critical current density (Ic) of 3.7 MA/$\textrm{cm}^2$ were measured from coated conductor deposited by stationary process. And coated conductor deposited by R2R continuous process had Ic of 57.5 A/cm-width, Tc of 86.5 K and Jc of 2.0 MA/$\textrm{cm}^2$. The film also exhibits a homogeneous and dense surface morphology.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.354-363
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• 2016

Purpose: The aim of this study was to investigate whether the application of nano-structured alumina coating to the surface of Y-TZP could enhance the bond strength with resin cement. Materials and methods: A total of 80 zirconia plates were prepared and divided into four groups. : 1) airborne particle abrasion treatment (A) : 2) Rocatec treatment after airborne particle abrasion (R) : 3) nano-structured alumina coating treatment after polishing (PC) and 4) nano-structured alumina coating after airborne particle abrasion (AC). Alumina coating was formed by the hydrolysis of aluminium nitride (AlN) powder and heat treatment at $900^{\circ}C$. Coating patterns were observed with FE-SEM. Resin block was bonded to treated zirconia ceramics using resin cement. The shear bond strengths were measured before and after thermocycling. Results: The FE-SEM images show a dense and uniform nano-structured alumina coating structure, which enhances shear bond strength by increasing micro mechanical interlocking to resin cement. PC and AC groups showed higher shear bond strengths than A and R groups before and after thermocycling. A and R groups displayed significant drops in shear bond strength after thermocycling. However, PC and AC groups did not show any meaningful decreases in shear bond strength after thermocycling. Conclusion: Treatment of Y-TZP ceramics with nano-structured alumina coating could significantly increase their shear bond strength.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.1
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• pp.48-54
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• 2009

Purpose: There are few studies evaluating the usefulness of dedicated high-resolution scintimammography and no studies using delayed washout with this dedicated high resolution scintimammography for the evaluation of breast lesions. We underwent this study to evaluate the clinical usefulness of Tc-99m MIBI in evaluating patients with palpable breast lesions using dedicated high-resolution scintimammography. Materials and Methods: This study included 19 patients with 23 palpable breast lesions who underwent mammography. Tc-99m MIBI was taken to further characterize these lesions. Scintimammography images were acquired with standard craniocaudal and mediolateral oblique views and delayed images were additionally taken. Final conclusions were based on histopathology, either by biopsy or mastectomy results. Results: Eighteen lesions were malignant and five were benign. Mammography was indeterminate for thirteen lesions, nine of those were malignant. Mammography also categorized one lesion as benign in a dense breast, but scintimammography and pathology results showed malignancy. Of the five benign lesions, two were visible on scintimammography, but delayed images showed washout. Conclusion: Based on our preliminary results, dedicated high resolution scintimammography seems to be very useful in characterizing palpable lesions that were indeterminate or negative on mammography.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.374-381
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• 1997

Ceramic membranes are prepared by using molding method of the glass materials, ceramic-silicone composite membranes are synthesized with immersing silicone compound of sodiumate, $S_3$-Al, S3and we investigated the properties of gas permeation. Ceramic membranes and ceramic-sodiumate membranes that has been prepared were identified as porous structure and ceramic-$S_3$-Al membranes and ceramic-$S_3$ membranes were showed with dense structure by immersion of silicone compounds. Gas permeation properties through the ceramic membranes and ceramic-sodiumate membranes decreased with increasing temperature and linearly increased with increasing pressure, ceramic-$S_3$-Al membranes and ceramic-$S_3$ membranes increased with increasing temperature and pressure effect was low. Permeation rate was found out high value with ceramic membranes and in order of ceramic-sodiumate membranes, ceramic-$S_3$-Al membranes and ceramic-$S_3$ membranes, but selectivity reversed in the order. Gas permeation mechanism through the ceramic membranes and ceramics-sodiumate composite membrane decreased with increasing temperature, suggesting an Knudsen diffusion mechanism, but ceramic-$S_3$-Al composite membranes and ceramic-$S_3$ composite membranes showed an activated diffusion by which gas permeation rates through the membranes increased with an increase in temperature.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.1-7
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• 2006

This paper attempts to locate and define a quartzite deposit in Geochang, Kyongsangnam Province in order to establish its commercial viability. The quartzite deposit (Poongwon Mine) occurs as lens or boudinage at the contact between mica schist of the Deogyusan formation and granite gneiss. During Precambrian, regional metamorphism and granitization may have caused the formation ot quartzite layers through recrystallization and rearrangement of silica components derived from older sedimentary rocks, probably chert and/or sandstone. The deposit is composed of fine-grained milky, or light yellowish quartz showing weak laminations with fairly dense and rough appearance in outcrop. It reaches about $60\;m(height)\times140\;m(length)\times35m(width)$ with attitude of $N57^{\circ}E-N8^{\circ}4E\;and\;51^{\circ}-60^{\circ}NW$. The average grade of the quartzite samples is $SiO_2=94.4\;wt\%,\;A1_2O_3=3.3\;wt\%,\; Fe_2O_3=0.8\;wt\%,\;K_2O=0.7\;wt\%$, which can be used for foundry, constructional materials, or concrete making. The proved reserve was estimated as 200,811 tonnage.

• Journal of fish pathology
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• v.18 no.2
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• pp.167-178
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• 2005

Streptococcus iniae is one of the major bacterial pathogens of cultured olive flounder, Paralichthys olivaceus in Korea. This study was carried out to investigate the interaction between morphological characteristics and immune response such as phagocytosis and serum killing activity. They were differentiated phenotypically into two groups, the viscous colonies and the non-viscous colonies, but the strains in both groups were similar in physiological and biochemical characteristics. Electron microscopic examination of the viscous form revealed thick, electron-dense exopolysaccharide materials surrounding polycationic ferritin-stained cells, while the exopolysaccharide material was absent around the non-viscous form of S. iniae. The viscous type strains were disclosed more virulent than those of non-viscous type for olive flounder. The viscous strains were resistant to normal serum killing activity, while the non-viscous strains were susceptible to bactericidal activity of normal serum from olive flounder. The viscous strains were more resistant to opsonophagocytosis and decreased the chemiluminescence response of head kidney macrophages of olive flounder. All of the tested non-viscous S. iniae strains were efficiently destroyed by the macrophage after phagocytosis. Both the viscous and the non-viscous strains invaded and replicated in cultured fish cell line (CHSE-2l4). This cellular invasion may contribute to the pathogenesis of invasive S. iniae infection.

• Applied Microscopy
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• v.24 no.2
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• pp.63-77
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• 1994

This experiment was performed to study the morphological responses of the epidermis of the rat scalp, following X-ray irradiation. Male rats were divided into normal and experimental groups. Rats anesthetized with sodium thiopental, were exposed only on their head areas with a single dose of 3,000rads or 6,000rads, respectively. Radiation was produced by Mitsubishi Linea Accelerator ML-4MV at the speed of 200rads/min. The target distance was 80cm. Animals were sacrificed on six hours, two days and six days following irradiation. By the perfusion fixation through the heart, rats were fixed with 1% glutaraldehyde-1% paraformaldehyde solution. Pieces of the tissue taken from the scalp were refixed in 2.5% glutaraldehyde-1.5% paraformaldehyde solution, followed by post-fixation with 1% osmium tetroxide, and embedded within araldite mixture. The sections were cut on a LKB-V ultratome, stained with uranyl acetate and lead citrate, and were observed with JEM 100CX-II electron microscope. The results were as follow; 1. Six hours after exposure to 3,000rads of X-ray. Disrupted intercellular spaces, within which some amorphous materials were filled, disrupted mitochondria, and vacuoles in the keratinocytes were frequently observed, but six days after exposure to 3,000rads of X-ray, Morphology of the keratinocytes was generally restored. 2. Many of the morphological changes were seen on the six days after exposure to 6,000rads of X-ray. 3. Widened intercellular spaces and thickened dense plaques of the desmosomes were frequently observed after exposure to 6,000rads of X-ray. 4. In the experimental groups, the Langerhans and the Merkel cells were damaged, similarly to the keratinocyte. Above results suggest that head irradiation with the dose of 3,000rads temporarily damaged the epidermis of the scalp, though most of the structures recover within six days, whereas with the dose of 6,000rads it severely damaged the epidermis without showing any recovering tendency.

• Applied Microscopy
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• v.27 no.4
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• pp.357-372
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• 1997

To study the age-related morphological differences of the retinal pigment cells and Bruch's membrane of mouse, retinae of one week-old, five weeks-old, eight weeks-old, six months-old, twelve months-old, eighteen months-old, twenty-four months-old and thirty months-old ICR mice were dissected out under anesthesia. Pieces of the tissue taken from the posterior region of the retina were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde (0.1 M Millonig's phosphate buffer, pH 7.3), and 1% osmium tetroxide (0.1 M Millonig's phosphate buffer, pH 7.3), and embedded in araldite mixture. The ultrathin sections were stained with uranyl acetate and lead citrate, and were observed under a JEM 100 CX-II electron microscope. Observed results were as follows: 1. Retinae of one week old mouse exhibit that some parts of the pigment cell provided with basal foldings, whereas other parts of the one contain without basal foldings. After (ive weeks-old, all retinal pigment cells have the basal infoldings. 2. In the one week-old, stage 1 and stage 2 melanosomes were observed in the retinal pigments cells, but after five weeks-old, most of the retinal pigment cells contain some matured stage melanosomes (stage III and stage IV). 3. The phagosomes in the retinal pigment cells were increased during aging. 4. After eighteen months-old, electron dense materials are observed within the basal infoldings. 5. After eighteen months-old, the thickness of the Bruch's membrane is prominently increased. The thickness of the basal laminae of the pigment cell and the choriocapillary endothelium is more prominently increased as compared with that of the other components of the Bruch's membrane. 6. The thickness of the basal lamina of the pigment cell is more prominently increased as compared with that of the choriocapillary endothelium on aging. From the above results, it was suggested that the pigment cell and Bruch's membrane matures structurally In five weeks, and the function of the pigment cell is prominently suppressed around eighteen months-old, and thereafter the functional suppression is continued on aging.

• Applied Microscopy
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• v.27 no.1
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• pp.13-30
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• 1997

The experiment was performed to study the morphological responses of the thymus of the mice, to antitumour agents (5-Fluorouracil or mitomycin C). Healthy adult mice weighing 25 gm each were divided into normal and experimental groups. 5-Fluorouracil (60 mg/kg) or Mitomycin-C $(400{\mu}g/kg)$ were injected subcutaneously to the animals every other day. Animals were sacrificed at 4 days and 7 days following the first injection. Pieces of the tissue taken from the thymus were prefixed with 2.5% paraformaldehyde-l.5% glutaraldehyde, followed by post-fixation with 1% osmium tetroxide. Ultrathin sections stained with uranyl acetate and lead citrate were observed with a JEM 100 CX-II electron microscope. The observed results were as follow: 1. Apoptoses of T-lymphocytes were observed more frequently in the thymus of the experimental groups than in those of a normal group. 2. In the experimental group, the plasma cells with distended cisternae of the granular endoplasmic reticulum and the eosinophile leukocytes were observed frequently. 3. In the experimental group, newly forming Hassall's corpurscles were observed frequently. 4. In the mitomycin-treated group, the epithelial reticular cells containing distended perinuclear cisternae, distended the granular endoplasmic reticula and pyknotic nuclei were observed in the cortico-medullary junctional area. 5. In the mitomycin-treated group, nuclear bodies with medium electron dense materials were often observed in the T lymphocyte. 6. In the 5-fluorouracil-treated groups, fused and dissolved tonofilament bundles and apoptotic bodies were observed in the some epithelial reticular cells in the medullary area. 7. In the 5-fluorouracil-treated groups, some elongated and bar-shaped lysosomes with electron lucent gap were often observed in the macrophages. 8. In the 5-fluorouracil-treated group, membrane complex of the smooth endoplasmic reticulum were ofen observed in the macrophage. From the above results, it was suggested that 5-fluorouracil or mitomycin could induce rapid involution of the thymus, and disturb maturation and differentiation of T lymphocytes, and, in turn, supress immunity.