• Title/Summary/Keyword: 박리선

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Morphological Study of the Regeneration of the Mouse Olfactory Epithelial Cells after Destruction by Intranasal Zinc Sulfate Irrigation (코 안 $ZnSO_4$ 점적으로 손상된 마우스 후각 상피세포의 재생에 대한 형태학적 연구)

  • Kang, Wha-Sun;Moon, Young-Wha
    • Applied Microscopy
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    • v.37 no.4
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    • pp.219-230
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    • 2007
  • The morphological effects of intranasal zinc sulfate(5% solution) irrigation on the mouse olfactory epithelium and the regeneration process of olfactory receptor cells following nasal irrigation were studied with scanning and transmission electron microscope. The results were as follows: 1. The septal epithelium except some basal cells was wholly detached from the basement membrane, during the first 6 to 24 hours after 5% zinc sulfate irrigation. 2. 3 days after $ZnSO_4$ treatment, two layered septal epithelium was formed from basal cells. And microvilli were observed in the apical epithelium of newly formed olfactory epithelial cells. 3. 5 days after treatment, a lot of centrosomes and basal bodies were observed in the olfactory receptor cells, and cilia were lined up between microvilli on the apical membrane of olfactory receptor cells. And immature olfactory knob was first observed in the newly formed olfactory receptor cells. Mature olfactory knob was observed 1 week after treatment. 4. There are very many mature olfactory knobs in the olfactory receptor cells 2 weeks after intranasal zinc sulfate irrigation. These results support that treatment with 5% zinc sulfate is a good experimental model for the regeneration of mammalian nervous tissues because this method could thoroughly detach the septal epithelium. During the regeneration of olfactory receptor cells, the surface membrane of the olfactory receptor cells widen the surface with the microvilli. Then cilia, which arranged in a line, substituted for the microvilli. The part of the surface membrane with cilia protruded and finally formed the olfactory vesicle.

Preparation and Characterization of Acrylic Bone Cement with Poly(methyl methacrylate)/Montmorillonte Nanocomposite Beads (폴리(메틸 메타크릴레이트)/몬모릴로나이트 나노복합체를 이용한 아크릴계 골시멘트의 제조 및 특성)

  • Lim Jin Sook;Son Eun Hee;Hwang Sung-Joo;Kim Sung Soo
    • Polymer(Korea)
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    • v.29 no.4
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    • pp.350-356
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    • 2005
  • Poly(methyl methauylate)/montmorillonite nanocomposites were incorporated into acrylic bone cement in order to improve the mechanical properties and reduce the exotherm of acrylic bone cement. The nanocomposites were prepared using a suspension polymerization and characterized by scanning electron microscopy, X-ray diffraction, trans-mission electron microscopy, gel permeation chromatography, particle size analyzer and electron dispersive spectroscopy. The acrylic bone cements with poly (methyl methacrylate)/nanocomposite s were prepared and their thermal and mechanical properties were characterized. The prepared polymeric beads were composed of polymer-intercalated nanocomposites with partially exfoliated MMT layers, and the mean diameter of them was $50\~60$ fm with the spherical shape. The maximum setting temperature of the acrylic bone cements decreased from 98 to $81\~87^{circ}C$. The mechanical strengths and moduli of the acrylic bone cement with 0.1 $wt\%$ MMT were increased. compared to that without MMT. However, the mechanical properties were generally decreased with increasing incorporated MMT amounts. It is presumably due to the bubbles in nanocomposite beads generated during polymerization.

Interfacial Adhesion Energy of Ni-P Electroless-plating Contact for Buried Contact Silicon Solar Cell using 4-point Bending Test System (4점굽힘시험법을 이용한 함몰전극형 Si 태양전지의 무전해 Ni-P 전극 계면 접착력 평가)

  • Kim, Jeong-Kyu;Lee, Eun-Kyung;Kim, Mi-Sung;Lim, Jae-Hong;Lee, Kyu-Hwan;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.1
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    • pp.55-60
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    • 2012
  • In order to develop electroless-plated Nickel Phosphate (Ni-P) as a contact material for high efficient low-cost silicon solar cells, we evaluated the effect of ambient thermal annealing on the degradation behavior of interfacial adhesion energy between electroless-plated Ni-P and silicon solar cell wafers by applying 4-point bending test method. Measured interfacial adhesion energies decreased from 14.83 to 10.83 J/$m^2$ after annealing at 300 and $600^{\circ}C$, respectively. The X-ray photoelectron spectroscopy analysis suggested that the bonding interface was degraded by environmental residual oxygen, in which the oxidation inhibit the stable formation of Ni silicide phase between electroless-plated Ni-P and silicon interface.

Size Control and Dispersion Properties of Illite Clay by Physicochemical Treatment (물리화학적 처리에 의한 일라이트 점토광물의 입도조절 및 분산특성)

  • Lim, Jae Won;Jeong, Euigyung;Seo, Kyeong-won;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.22 no.2
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    • pp.133-137
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    • 2011
  • In this study, illite was size-reduced using a wet-ball-milling treatment to improve its dispersion. Changes in illite particle size, size distribution, and dispersion characteristics after varying the treatment period were investigated. And the dispersion and dispersion stability of illite solution after 2 h wet ball milling treatment with different pH conditions were also evaluated. The illite particle size significantly decreased as the treatment time increased and the size reduction effect of wet ball milling deteriorated above 2 h treatment time. In addition, illite particle size was more evenly distributed as the treatment time increased. X-ray diffraction (XRD) analysis showed that no crystal structural changes of illite were induced, but the characteristic peak of illite the weaker due to the size reduction and exfoliation, as the treatment time increased. Zeta potential analysis showed that the illite dispersion improved, as the treatment time increased. The illite wet-ball-mill treated at pH 2 had the lowest dispersion stability. Illite dispersion and dispersion stability increased as pH increased, due to the increase in surface ionization. Hence, the results showed that as the treatment time increased, the illite particle size decreased, and dispersion and dispersion stability improved due to the increase in surface energy and repulsion force between particles.

Evaluation and Weathering Depth Modeling of Thermally Altered Pelitic Rocks based on Chemical Weathering and Variations: Ulju Cheonjeon-ri Petroglyph (화학적 풍화작용과 조성변화에 따른 열변질 이질암의 풍화심도 모델링 및 평가: 울주 천전리 각석)

  • LEE Chan Hee;CHUN Yu Gun
    • Korean Journal of Heritage: History & Science
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    • v.56 no.4
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    • pp.160-189
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    • 2023
  • The Cheonjeon-ri petroglyph is inscribed with shale formation belonging to the Daegu Formation of the Gyeongsang Supergroup in the Cretaceous of the Mesozoic Era. This rock undergoes thermal alteration to become hornfels, and has a high hardness and dense texture. Rock-forming minerals have almost the same composition as quartz, alkali felspar, plagioclase, calcite, mica, chlorite and opaque minerals, but calcite is rarely detected in the weathered zone. The petroglyph forms a weathered zone with a certain depth, and there is a difference in mineral and chemical composition between weathered and unweathered zones, respectively. The CaO contents of the weathered zone were reduced by more than 90% compared to that of the unweathered zone, because calcite reacted with water and dissolved. As a result of calculating the surface weathering depth for the petroglyph with the transmission characteristics of X-rays, depth of the parts in falling off and exfoliation showed a depth of about 0.5 to 1 mm, but the weathering depth in most areas was calculated to be about 3 to 4 mm. This can be proved by the contents and changes of Ca and Sr. The surface discolorations of the petroglyph are distributed with different color density, and the yellowish brown discoloration is alternated with a thin biofilm layer, showing a coverage of 79.6%. Therefore, periodic preservation managements and preventive conservation monitoring that can effectively control the physicochemical and biological damages of the Cheonjeonri petroglyph will be necessary.

Toxicity and Carcinogenicity of the Fusarium moniliforme MRC 826 Culture Material in Rats (랫드에서 Fusarium moniliforme MRC 826 배양물질의 독성 및 발암성에 관한 연구)

  • 신동진;신광순;이영순
    • Journal of Food Hygiene and Safety
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    • v.8 no.1
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    • pp.37-53
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    • 1993
  • F. moniliforme MRC 826, a common fungal contaminant of com, has been known to produce a group of mycotoxins, the fumonisins. By thin layer chromatography, fumonisin $B_{1}$ was detected in the F. moniliforme MRC 826 com culture material(CM) extracts. This study was performed to compare the toxicity and carcinogenicity of F. moniliforme MRC 826 CM with those of aflatoxin $B_1(AFB_1)$ in rats. The toxicity was tested over a period of 7 days in ten female Sprague-Dawley (SD) rats. Treatment group were fed a 1 : 1 mixture(wt/wt) of ground CM and basal diet in powder form, while other negative control group were given basal diet alone. The principal pathological changes in rats treated with 50% CM were hepatocellular hydropic degeneration and renal tubular necrosis. The cancer-promoting activity of CM was evaluated in the rat liver diethylnitrosamine-two thirds partial hepatectomy(DEN-PH) model for carcinogenesis. 70 male SO rats(ca. 170 g) were randomized into 5 groups. Group I served as the positive controls and received the basal diet containing 2 ppm $AFB_{1}$ group 2 received 5% CM, group 3 received 2.5% CM, group 4 received 5% normal com and group 5 received 2.5% normal com. 5% treated group showed cancer promoting activity in rat liver using DEN as initiator and the induction of glutathione S-transferase placental form positive foci as an end point after 6 weeks of promotion.

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Electrochemical Characteristic on Hydrogen Intercalation into the Interface between Electrolyte of the 0.1N H2SO4and Amorphous Tungsten Oxides Thin Film Fabricated by Sol-Gel Method (졸-겔법으로 제조된 비정질의 텅스텐 산화물 박막과 황산 전해질 계면에서 일어나는 수소의 층간 반응에 대한 전기화학적 특성)

  • Kang, Tae-Hyuk;Min, Byoung-Chul;Ju, Jeh-Beck;Sohn, Tae-Won;Cho, Won-Il
    • Applied Chemistry for Engineering
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    • v.7 no.6
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    • pp.1078-1086
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    • 1996
  • The peroxo-polytungstic acid was formed by the direct reaction of tungsten powder with the hydrogen peroxide solution. Peroxo-polytungstic powder were prepared by rotary evaporator using the fabricated on to ITO coated glass as substrate by dip-coating method using $2g/10mL(W-IPA/H_2O)$ sol solution. A substrate was dipped into the sol solution and after a meniscus had settled, the substrate was withdrawn at a constant rate of the 3mm/sec. Thicker layer could be built up by repeated dipping/post-treatment 15 times cycles. The layers dried at the temperature of $65{\sim}70^{\circ}C$ during the withdrawn process, and then tungsten oxides thin film was formed by final heating treatment at the temperature of $230{\sim}240^{\circ}C$ for 30min. A linear rotation between the thickness of thin film and the number of dipping/post-treatment cycles for tungsten oxides thin films made by dip-coating was found. The thickness of thin film had $60{\AA}$ after one dipping. From the patterns of XRD, the structure of tungsten oxides thin film identified as amorphous one and from the photographs of SEM, the defects and the moderate cracks were observed on the tungsten oxides thin film, but the homogeneous surface of thin films were mostly appeared. The electrochemical characteristic of the $ITO/WO_3$ thin film electrode were confirmed by the cyclic voltammetry and the cathodic Tafel polaization method. The coloring bleaching processes were clearly repeated up to several hundreds cycles by multiple cyclic voltammetry, but the dissolved phenomenon of thin film revealed in $H_2SO_4$ solution was observed due to the decrease of the current densities. The diffusion coefficient was calculated from irreversible Randles-Sevick equation from the data obtained by the cyclic voltammetry with various scan rates.

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