• The Korean Journal of Cytopathology
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• v.7 no.1
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• pp.23-30
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• 1996

Chromatin texture, which partly reflects nuclear organization, is evolving as an important parameter indicating cell activation or transformation. In this study, chromatin pattern was evaluated by image analysis of the electron micrographs of follicular and papillary carcinoma cells of the thyroid gland and tested for discrimination of the two neoplasms. Digital grey images were converted from the electron micrographs, nuclear images, excluding nucleolus and intranuclear cytoplasmic inclusions, were obtained by segmentation; grey levels were standardized; and grey level histograms were generated. The histograms in follicular carcinoma showed Gaussian or near-Gaussian distribution and had a single peak, whereas those in papillary carcinoma had two peaks(bimodal), one at the black zone and the other at the white zone. In papillary carcinoma, the peak in the black zone represented an increased amount of heterochromatin particles and that at the white zone represented decreased electron density of euchromatin or nuclear matrix. These results indicate that the nuclei of follicular and papillary carcinoma cells differ in their chromatin pattern and the difference may be due to decondensed chromatin and/or matrix substances.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.9-15
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• 2008

An investigation was carried out to examine the pores of casting bodies depending on the position of wax pattern in the ring for precious alloy by optical micrographs. From the result of optical micrographs, many pores were found in the Group C that wax pattern is placed in the center of the ring. However, any pores were scarcely found in the Group A, B, D and E that wax patterns are placed out of the center of thermal zone. In comparison with the pores of casting bodies of Group C, many pores were found at the cusp area rather than at the proximal surface. From these examination, it was concluded that wax pattern should be placed out of the center of thermal zone to prevent casting boies from occurring pores.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.21-28
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• 2003

The purpose of this study was to process bio-active glass ceramic composite, reinforced with sapphire fibers, by hot press. Also to study the interface of the matrix and the sapphire fiber, and the mechanical properties. Glass raw materials melted in Pt crucible at 1300$^{\circ}C$ during 3.5 hours. The melt was crushed in ball mill and then crushed material, ground and sieved to $<40{\beta}{\mu}m$. Sapphire fibers cut (30mm) and aligned. Powder and fibers hot pressed. The micrographs show good bonding between the matrix and the fiber and no porosity in the glass matrix. This means ideal fracture phenomena. Glass is fractured before the fiber. This is indication of good fracture strength. EDXS showing aluminum rich phase and crystalline phase. Bright field image of the matrix showing crystalline phase. Also diffraction pattern of TEM showing the crystalline phase and more than one phase. Strength of the samples was determined by 3 point bend testing. Strength of the 10vol% sample was approximately 69MPa, while strength of the control sample is 35MPa. Conclusions through this study as follow: 1. Micrographs show no porosity in the glass matrix and the interface. 2. The interface between the fiber and the glass matrix show no gaps. 3. Fracture of the glass indicates characteristic fiber-matrix separation. 4. Presence of crystalline phase at high processing temperature. 5. Sapphire is compatible with bioactive glass.

• Biomedical Science Letters
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• v.6 no.2
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• pp.109-118
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• 2000

The bronchus and alveoli from young rats have been examined by electron microscope following the exposure of cigarette smoking. Experimental animals were exposed to the sidestream smoke in an experimentally designed cage for 45 minutes per day during four weeks. In the smoking group, transmission electron micrographs of lung tissues showed a large number of neutrophils with electron densed several lysosomes, numerous macrophages with many small lysosomes, and many residual bodies in alveolar space. Scanning electron micrographs revealed that the ciliated epithelial cells in bronchus of smoking group were replaced by goblet cells including loss of cilia, and increased cell size of many goblet cells in bronchus. These results depicted that the ultrastructural changes are due to the passive smoking, involving airway cell Injury.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.107-114
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• 2005

Molecular aggregates of surfactant molecules consisting of one or more bilayers arranged in a hollow, closed, usually spherical geometry are termed “esicles”or “iposomes” In recent years it has been found that in certain systems the vesicular structure forms spontaneously and is long lived, and it has been suggested that these structures may in fact constitute the equilibrium state in these cases (as is true of micelles) This paper deals with the mixed CMC, vesicles, phase behavior, phase transition, geometrical structure, their formation and characterization in the aqueous solutions of mixed cationic/anionic surfactants systems. TEM micrographs revealed that the vesicles were of spherical shape and that their size was of around 180 nm. The zeta potentials are positive at CGS1-rich regions and negative at SLES-rich regions. In the region where SLES/CGS1 (6/4), the zeta potentials are very small, implying that the vesicles at this surfactant ratio may be less stable. At other surfactant ratios, the vesicles are thought to be stable, supported by large absolute values of zeta potentials and little change in UV absorbance for several months.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.9-15
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• 1999

Die-sinking electrical discharge machining(EDM) for conductive ceramic matrix composite(CMC) of Tic/$Al_2O_3$ was experienced with addition of ultrasonic emission, and the results were compared with ones obtained by the EDM only. From this experimental study, the values of material removal rate(MRR) and surface roughness($R_{max}$), scanning electron microscope(SEM) micrographs, and weibull probability distribution of bending strength for the specimens were obtained and compared. The trend of MRR was found to be increased slightly with the current and the duty factor for both EDM only and EDM with ultrasonic emission. The MRR values were found to be increased for EDM with ultrasonic emission. The SEM micrographs of EDMed surface by under various operating conditions showed less micro cracks in various places. Although smaller bending strength value was obtained by EDMed surface with ultrasonic emission by weibull probability distribution analysis of bending strength.

• Advanced Composite Materials
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• v.18 no.3
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• pp.221-232
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• 2009

The allylamine plasma treatment is used to modify the surface properties of vapor grown carbon fibers (VGCF). It is to improve the interfacial bonding between the VGCF and epoxy matrix. The allylamine plasma process was performed by batch process in a vacuum chamber, using gas injection followed by plasma discharge for the durations of 20, 40 and 60 min. The interdependence of mechanical properties on the VGCF contents, treatment time and interfacial bonding between VGCF/ep was investigated. The interfacial bonding between VGCF and epoxy matrix was observed by scanning electron microscopy (SEM) micrographs of nanocomposites fracture surfaces. The changes in the mechanical properties of VGCF/ep, such as the tensile modulus and strength were discussed. The mechanical properties of allylamine plasma treated (AAPT) VGCF/ep were compared with those of raw VGCF/ep. The tensile strength and modulus of allyamine plasma treated VGCF40 (40 min treatment)/ep demonstrated a higher value than those of other samples. The mechanical properties were increased with the allyamine plasma treatment due to the improved adhesion at VGCF/ep interface. The modification of the carbon nanofibers surface was observed by transmission electron microscopy (TEM). SEM micrographs showed an excellent dispersion of VGCF in epoxy matrix by ultrasonic method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.260-262
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• 2003

A thermal vapor deposition method for crystallization of insoluble analytes with matrix is established as a new sample preparation method for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). A mixture of mono, bis and tris(p-ethyl benzylidene) sorbitols was incorporated into microcrystals of ferulic acid, which was confirmed by confocal micrographs. Molecular masses of sorbitol derivatives were determined in this way by MALDI-MS without thermal decomposition.

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.161-168
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• 1990

To evaluate the corrosion behavior of reaction bonded silicon carbides, corrosion test was studied for various corrosive environments. Corrosion test for reaction bonded silicon carbides was conducted at 900$^{\circ}C$ under four different gas atmospehres ; air, So2-air, Cl2-O2-Ar, Cl2-N2 and investigated these samples using weight loss, bending strength, XRD, optical micrographs and EDS respectively.

• Journal of Species Research
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• v.7 no.1
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• pp.80-91
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• 2018

The following seven species of soil enchytraeids belonging to five genera were collected from Korea: Enchytraeus buchholzi $Vejdovsk{\acute{y}}$, 1878, Enchytraeus irregularis Nielsen & Christensen, 1961, Fridericia bulboides Nielsen & Christensen, 1959, Hemifridericia parva Nielsen & Christensen, 1959, Henlea perpusilla Friend, 1911, Henlea ventriculosa (Udekem, 1854), and Marionina argentea Michaelsen, 1889 sensu lato. Species were found in soil and litter layers of sites investigated in 2007, 2008 and 2014. Diagnoses or descriptions for these species are provided here with new micrographs or drawings.