• Journal of Korea Foundry Society
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• v.15 no.4
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• pp.408-415
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• 1995

Polycrystalline Al-Cu ribbons were produced by planar flow casting(PFC). Solidification behavior and microstructual changes of the ribbons have been investigated as a function of ribbon thickness and processing parameters. The solidification front velocity, V varies within the ribbon, decreasing with increasing the distance, S from the wheel-contact surface, as $V=17.6S^{-1}$. In Al-4.5wt%Cu alloy, rapid decrease in solidification velocity toward the free surface causes a change in solidification morphology from planar to cellular, and finally, to dendritic. The length and inclination of columnar grains solidified with planar front were related to the wheel velocity. The transition from particulate degenerate eutectic structure to regular lamellar eutectic structure was observed to be caused by a difference of the relative growth velocites of ${\alpha}-Al$ and ${\theta}$ during solidification in the Al-Cu eutectic alloy.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.177-181
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• 2009

Compositional gradient CrNx coatings were fabricated using arc ion plating in Ar/$N_2$ gaseous mixture by gradually increasing $N_2$ flux rate from 0 to 120 SCCM. The effect of negative substrate bias on the film microstructure and mechanical properties were systematically investigated with XRD, GDOES, and SEM. The results show that substrate bias has an important influence on film growth and microstructure of gradient CrNx coatings. The coatings mainly crystallized in the mixture of hexagonal $Cr_{2}N$ and fcc CrN phases. By increasing substrate bias, film microstructure evolved from an apparent columnar structure to an equiaxed one. With increasing substrate bias, deposition rate first increased, and then decreased. The maximum of deposition rate was 15 nm/min obtained at a bias of -50V.

• Journal of the Korean institute of surface engineering
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• v.18 no.2
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• pp.53-60
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• 1985

The microstructure of zine electrodeposits was investigated by using zinc sulfate solution in still bath. The cathode current efficiency decreased with increasing current density, and decreasing temperature. The preferred orientation of the zinc electrodeposits changed from (10.3) texture to(10.${\ell}$)-(00.1)(${\ell}$=1, 2, 3) texture through (10.2)-(10.3) preferred orientation with increasing cathode over potential. The surface morphology of zinc electrodeposits changed from the dendritic growth with granular crystallites to the blocks of hexagonal crystallites packed together with increasing current density. The microstructure of cross section of the above deposits are the rough granular structure and columnar structure respectively.

• Journal of the Korean institute of surface engineering
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• v.30 no.5
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• pp.298-309
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• 1997

Hard Tin coating on tool steel substrate were prepared using the pulsed PACVE. An orthogonal experimental design was employed to find the best deposition conditions for TiN coating and to systematically understand the effect of processing parameters. The small size Taguchi matrix called the L16 was used for experiment and ANOVA(ANalysis of VAriance) was followed to study the effect of main parameters on hardness and adhesion TiN coatings. In conclusion, pulse on/off time ratio and pulsing frequency were the major deposition parameters to determine hardness and adhesion of TiN coating in the pulsed DC PACVE process. (200) preferred orientation, columnar growth and dome-shaped surface morphology of the TiN films gave rise to a high hardness and a good adhesion to the substrates.

• Korean Journal of Bronchoesophagology
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• v.6 no.1
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• pp.108-112
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• 2000

Epithelial-myoepithelial carcinoma(EMC) is a rare low grade malignant salivary gland neoplasm that most commonly occurs in the parotid gland but can also arise in minor salivary glands. It is a distinct neoplasm characterized by tubular and solid growth patterns and a dual cell population including an inner larger of cuboidal to columnar epithelial cells which are peripherally bounded by a layer of myoepithelial cells with distinctly clear cytoplasm. The clinical course is characterized by a high incidence of local recurrence and not infrequent distant metastasis. The differential diagnosis included acinic cell tumor, adenoid cystic carcinoma, mucoepidermoid carcinoma, sebaceous carcinoma and pleomorphic adenoma. We report a case of EMC of left parotid gland in a 55-year-old woman.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2094-2096
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• 2005

In this paper, we studied the cross section analysis based on the short circuit conditions of the low voltage bare wires. The copper wires prepared for the experiment were 1.2mm 1.6mm and 2.0mm in diameter. Through the cross section analysis(CSA), it was confirmed that the dendrite structure grew at the angle of about $40^{\circ}$ or $60^{\circ}$ when the fusing current was applied to the wires. The larger the fusing current is, the more decreased the growth angle of the dendrite structure is. It was confirmed that the dendrite structure was arranged like the columnar structure. In this paper, the characteristics analysis of short circuit was carried out in the range of transient duration.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.401-405
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• 1999

Reflective silver films with high quality were prepared on polyester substrate by using sputter deposit on techniques. Best reflectivity thin films of silver were produced with process parameters of $10^{-6}$ Torr as base pressure, 50 W as R.F. power, 5 mTorr as working pressure, and 10 sccm as Ar flow rate. Being deposited with an R.F. power of 50 W, Ag films revealed the highest 96.3 % reflectance as illuminated with a light of 700 nm wavelength. The adhesion of sample films showed as high as 14 to $20{\;}kg/\textrm{cm}^2$, which is suitable for industrial purposes. Their film crystallinity and orientation resulted in the planes of (111) and (200) for the growth with a preferred orientation of <111>, in general. The cross-sections of thin film specimens showed columnar structures. It is noted that columns became coarsened and less dense as R.F. power increased, resulting in a low reflectivity for the product film.

• Korean Journal of Veterinary Research
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• v.59 no.1
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• pp.51-54
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• 2019

Pulmonary masses were observed in the thoracic cavity of a 9-year-old female Korean native cattle (Hanwoo) encountered at a Jeju, Korea slaughterhouse. Grossly, the thoracic cavity was filled with pulmonary masses. Histologically, the neoplastic masses were composed of many abnormal papillary structures lined by single to double columnar neoplastic cells and formed arborizing fronds supported by significant fibrovascular stroma. The neoplastic cells showed strong destructive and infiltrative growth to adjacent tissues and were strongly positive for pan-cytokeratin (CK), CK 7 and sporadically positive for CK MNF116. The masses in the female Hanwoo were diagnosed as a papillary pattern of pulmonary adenocarcinoma.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.1
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• pp.44-55
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• 1996

Emerald (3BeO{\cdot}Al$_{2}$O_{3}{\cdot}6SiO_2 : Cr^{3+}$) single crystals were grown by flux method of $Li_2O-MoO_3 - V_2O_5$ system. The composition of starting materials were 1, 3, 5 mole ratio of $MoO_3 - V_2O_5/$Li_2O$, 20 - 15% of emerald content to flux composition and 1% of $Cr_2O_3$ colordopant to emerald composition. After mixing those were melted at $1100^{\circ}C$ in Pt crucible of electric furnace. Single crystal growth was cooled down slowly rate of $3^{\circ}C$/hr from $1100^{\circ}C$ to $650^{\circ}C$, for the cooling period it was controlled and prevented the nucleation of microcrystallite from variation of each thermal fluctuation range. Specially it has been obtained plenty of large emerald single crystal when thermal fluctuation was treated for cooling period at $1050 ~ 950^{\circ}C$, in 3 mole ratio of $V_2O_5 - MoO_3/Li_2O$ flux. Emerald single crystal growing effect and $Cr_{+3}$ ion of substitutional solid solution effect for $Al_{+3}$ ion was good than mole ratio of 5. Emerald single crystals were c (0001) hexagonal rystal face of preferencial direction and m (1010) post side. Emerald was hexagonal columnar greenish transparent and 2.65 ~ 2.66 of specific gravity.

• Journal of Plant Biology
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• v.17 no.3
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• pp.118-126
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• 1974

Mulberry plants cultivated in mid-Korea were studied on the growth habitat, canopy type, productive structure and vertical light intensity in relation to the quality of mulberry leaves for sericulture. The growth in length of new branch of summer cut mulberry in spring was vigorous on the uppermost of old shoot. Numbers of leaves on a branch were barely 4 leaves on lower than 20th branch from base, but those were 13 leaves on higher than 24th branch. Area of leaves completely expanded was broad on high branch, but narrow on low one. The form of canopy, the type of productive structure and the vertical light distribution depend upon varieties of cultivated mulberry plants were classified according to characteristic of each variety in two groups, respectively; globular and columnar form in canopy, broad leaves and narrow leaves types in productive structure, and seriously obstructured the light and fairly transmitted the light into lower leaf stratum invertical light distribution. Out of varieties of mulberry investigated, Suwon No. 4 and Rosang were belong to the former characters, but Illchiroe and Kaeryangsubun were to the latters. The values of leaf dry matter index and dry matter production produced by leaves were increased in direct proportion to the height of leaf stratum; the leaf dry matter index of the uppermost leaf was twice as much that of the lowest, and the dry matter production by the highest leaf was 17 times compared with that by the lowest leaf. It is assumed that the meagre leaves occurred in the lower leaf stratum of Suwon No. 4 and Rosang were caused to diminished the dry matter index and dry matter production in the under leaves of plant, which were affected by receiving the weak light.