• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1423-1431
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• 2015

A clique-transversal set D of a graph G is a set of vertices of G such that D meets all cliques of G. The clique-transversal number is the minimum cardinality of a clique-transversal set in G. For every cubic graph with at most two bridges, we first show that it has a perfect matching which contains exactly one edge of each triangle of it; by the result, we determine the exact value of the clique-transversal number of line graph of it. Also, we present a sharp upper bound on the clique-transversal number of line graph of a cubic graph. Furthermore, we prove that the clique-transversal number of line graph of a triangle-free graph is at most the chromatic number of complement of the triangle-free graph.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.35-41
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• 1999

STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

• Restorative Dentistry and Endodontics
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• v.7 no.1
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• pp.53-57
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• 1981

A total of 130 extracted human maxillary second molars were used to study the configuration of the floor of the pulp chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 16.9% of the teeth were quadrilateral, 70.0% were triangle and 13.1% were ovoid shape. 2. 13.1% of the specimens have 4 root canal orifices. 73.9% have 3 root canal orifices, 11.5% have 2 root canal orifices and 1.5% have single orifice. 3. 13.1% of the specimens have 2 mesio-buccal canal orifices and among the teeth those have 3 canals, 20.8% show 'Y' shape, 29.1% show straight line and 23.8% show obtuse triangle shape.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.129-134
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• 1998

STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

• The Journal of the Korean dental association
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• v.22 no.5 s.180
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• pp.423-427
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• 1984

A total of 114 extracted human mandibular first molars were used to study the configuration of the floor of the chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 58.8% of the teeth were square, 34.2% were triangle and 7.0% were ovoid shape. 2. 58.8% of the specimens have 4 root canal orifices, 34.2% have 3 root canal orifices, 7.0% have 2 root canal orifices. 3. 41.2% of the specimens show 'H' shape, 17.6% show 'Square' shape, 31.6% show 'T' shape, 2.0% show 'reverse-T' shape and 7.0% show 'I' shape.

• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.533-544
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• 2013

The multiplicative version of Wiener index (${\pi}$-index), proposed by Gutman et al. in 2000, is equal to the product of the distances between all pairs of vertices of a (molecular) graph G. In this paper, we first present some sharp bounds in terms of the order and other graph parameters including the diameter, degree sequence, Zagreb indices, Zagreb coindices, eccentric connectivity index and Merrifield-Simmons index for ${\pi}$-index of general connected graphs and trees, as well as a Nordhaus-Gaddum-type bound for ${\pi}$-index of connected triangle-free graphs. Then we study the behavior of ${\pi}$-index upon the case when removing a vertex or an edge from the underlying graph. Finally, we investigate the extremal properties of ${\pi}$-index within the set of trees and unicyclic graphs.

• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.165-169
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• 1986

A total of 114 extracted human mandibular 2nd molars were used to study the configuration of the floor of the chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows, 1. In so far as observing the shape of the pulp chamber of the teeth, 47.4% of the teeth were square, 42.9% were triangle and 9.7% were ovoid shape. 2. 35% of the samples had 2 root canal orifices, 62% had 3 root canal orifices, 3% had 4 root canal orifices. 3. 3% of the specimens showed 'H' shape, 5% showed 'Square' shape, 51% showed 'T' shape, 1% showed 'reverse-T' shape, 35% showed 'I' shape and 5% showed the specific 'C' shape.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.105-107
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• 1980

A total of 125 extracted maxillary first molars were used to study the configuration of the floor of the pulp chamber. The specimens were ground and the pulp chamber was examined with a magnifying glass and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 50.4% of the teeth were trapezoid, 20.8% were inverted trapezoid, 18.4% were rectangle and 10.4% were triangle shape. 2. 71.2% of the specimens have 3 root canal orifices, and 28.8% have 4 root canal orifices. 3. 71.2% of the specimens have 1 mesiobuccal canal orifice, 23.2% have 2 mesio-buccal canal orifices joined by a groove, and 5.6% have 2 mesio-buccal canal orifices seperated each other.

• Geosystem Engineering
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• v.21 no.6
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• pp.309-317
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• 2018

We employ a three-dimensional indirect boundary element method (BEM) to simulate temperature change around an underground liquefied natural gas storage cavern. The indirect BEM (IBEM) uses fictitious heat source strength on boundary elements as basic variables which are solved from equations of boundary conditions and then used to compute the temperature change at other points in the considered problem domain. The IBEM requires evaluation of singular integration for temperature change due to heat conduction from a constant heat source on a planar (triangular) region. The singularity can be eliminated by a semi-analytical integration scheme. However, it is found that the semi-analytical integration scheme yields sharp temperature gradient for points close to vertices of triangle. This affects the accuracy of heat flux, if they are evaluated by finite difference method at these points. This difficulty can be overcome by a combination of using a direct numerical integration for these points and the semi-analytical scheme for other points distance away from the vertices. The IBEM and the hybrid integration scheme have been verified with an analytic solution and then used to the application of the underground storage.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.177-183
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• 2008

The layers of keratinocytes form an acid mantle on the surface of the skin. Herein, we investigated the effects of acidic pH on the membrane current and $[Ca^{2+}]_c$ of human primary keratinocytes from foreskins and human keratinocyte cell line (HaCaT). Acidic extracellular pH ($pH_e{\leq}5.5$) activated outwardly rectifying $Cl^-$ current ($I_{Cl,pH}$) with slow kinetics of voltage-dependent activation. $I_{Cl,pH}$ was potently inhibited by an anion channel blocker 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS, 73.5% inhibition at 1${\mu}$M). $I_{Cl,pH}$ became more sensitive to $pH_e$ by raising temperature from $24^{circ}C$ to $37^{circ}C$. HaCaT cells also expressed $Ca^{2+}$-activated $Cl^-$ current ($I_{Cl,Ca}$), and the amplitude of $I_{Cl,Ca}$ was increased by relatively weak acidic $pH_e$ (7.0 and 6.8). Interestingly, the acidic $pH_e$ (5.0) also induced a sharp increase in the intracellular [$Ca^{2+}$] (${\triangle}[Ca^{2+}]_{acid}$) of HaCaT cells. The ${\triangle}[Ca^{2+}]_{acid}$ was independent of extracellular $Ca^{2+}$, and was abolished by the pretreatment with PLC inhibitor, U73122. In primary human keratinocytes, 5 out of 28 tested cells showed ${\triangle}[Ca^{2+}]_{acid}$. In summary, we found $I_{Cl,pH}$ and ${\triangle}[Ca^{2+}]_{acid}$ in human keratinocytes, and these ionic signals might have implication in pathophysiological responses and differentiation of epidermal keratinocytes.