• Korean Journal of Mathematics
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• v.13 no.2
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• pp.161-176
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• 2005

We consider a model of population dynamics whose mortality function is unbounded. We note that the regularity of the solution depends on the growth rate of the mortality near the maximum age. We propose Gauss-Legendre methods along the characteristics to approximate the solution when the solution is smooth enough. It is proven that the scheme is convergent at fourth-order rate in the maximum norm. We also propose discontinuous Galerkin finite element methods to approximate the solution which is not smooth enough. The stability of the method is discussed. Several numerical examples are presented.

• Journal of the Korean Mathematical Society
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• v.61 no.4
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• pp.743-760
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• 2024

In this paper, we are devoted to study a forth order curve flow for a smooth closed curve in centro-affine geometry. Firstly, a new evolutionary equation about this curve flow is proposed. Then the related geometric quantities and some meaningful conclusions are obtained through the equation. Next, we obtain finite order differential inequalities for energy by applying interpolation inequalities, Cauchy-Schwartz inequalities, etc. After using a completely new symbolic expression, the n-order differential inequality for energy is considered. Finally, by the means of energy estimation, we prove that the forth order curve flow has a smooth solution all the time for any closed smooth initial curve.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.7
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• pp.642-648
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• 2000

Falling film heat transfer analyses with aqueous lithium bromide solution were peformed to investigate the transfer characteristics of the copper tubes. Finned(knurled) tube and a smooth tube were selected as test specimens. Averaged generation fluxes of water and the heat transfer performances(heat flux, heat transfer coefficient) were obtained. The results of this work were compared with the data reported previously. As the film flow rate of the solution increased, the generation fluxes of water decreased for both tubes. The reason is estimated by the fact that the heat transfer resistance with the film thickness increased as the film flow rate increased. The effect of the enlarged surface area at the knurled tube was supposed to be dominant at a small flow rate. The generation fluxes of water increased with the increasing degree of tube wall superheat. Nucleate boiling is supposed to occur at a wall superheat of 20 K for a smooth tube, and at 10 K for a knurled tube. The heat transfer performance of the falling film was superior to pool boiling at a low wall superheat below 10 K for both tubes tested. The knurled tube geometry showed good performance than the smooth tube, and the increased performance was mainly came from the effect of the increased heating surface area.

• The Journal of the Korean dental association
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• v.12 no.5
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• pp.327-332
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• 1974

The effects of enamel solubility by the varying concentration of fluoride and phosphate as well as pH of the acid fluoride-phosphate solutions were tested and compared with th 7% stannous fluoride solution. The smooth surface of the sound permanent 1st premolars were demineralized by the Buttner's method. And the phosphorus extracted from the 1st premolars were analyzed by the Fiske and Subbarow's method. Enamel smooth surfaces treated with the acid fluoride-phosphate solution and the 8% stannous fluoride solution were obserbed electron-microscopically by the Filmy Replica method. The results of this study were summarized as follows: !. The least enamel dissolution rate was observed at the acid fluoride-phosphate solution contained 1.25% fluorine, 0.5% phosphate, and pH 4. 2. The anti-cariogenic effects comparison between the acid fluoride-phosphate solution and 8% stannous fluoride, the former was higher.

• Bulletin of the Korean Mathematical Society
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• v.46 no.3
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• pp.409-434
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• 2009

In this paper, we consider a generalized Riemann problem of the first order hyperbolic conservation laws. For the case that excludes the centered wave, we prove that the generalized Riemann problem admits a unique piecewise smooth solution u = u(t, x), and this solution has a structure similar to the similarity solution u = $U{(\frac{x}{t})}$ of the correspondin Riemann problem in the neighborhood of the origin provided that the coefficients of the system and the initial conditions are sufficiently smooth.

• Korean Journal of Mathematics
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• v.4 no.2
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• pp.83-88
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• 1996

In 1994 Z.Liang constructed an iterative method for the solution of nonlinear equations involving m-accretive operators in uniformly smooth Banach spaces. In this paper we apply the slight variants of Liang's iterative methods and generalize the results of Z.Liang. Moreover our proof is more simple than Liang's proof.

• The Journal of Internal Korean Medicine
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• v.11 no.1
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• pp.165-177
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• 1990

In order to study the effects of HWA GAE SAN known clinically for their effects of treatment for cough and asthma, the study was carried out to investigate the effect of HWA GAE SAN extract on the contractile force of isolated guinea pig trachea smooth muscle and elucidate its mechanism. The results were obtained as follows. 1. Preparation of isolated guinea pig trachea smooth muscle was suspended in the oxygeneted Kreb's Henseleit bicarbonate buffer solution at $37^{\circ}C$ and recorded the developed tension by the drug with the isometric transducer (Nacro F-60). The restin tension was approximately 0.5g. 2. The trachea smooth muscle in normal state showed a significant atony to the increase of density of HWA GAE SAN. 3. The atonic effect of the trachea smooth muscle was restricted after prescription of Pyrilamine& Cyproheptadine. Hireceptor broker, which were prearranged. 4. After 5, 15, 50& $150{\mu}l/ml$ of HWA GAE SAN were prescribed, the atony of trachea smooth muscle was caused by Histamine. 5. After 50& $150{\mu}l/ml$ of HWA GAE SAN were prescribed, the atony of trachea smooth muscle was remarkably dwindled which was caused by Acetylcholine. 6. After $150{\mu}l/ml$ of HWA GAE SAN were prescribed, the atony of trachea smooth muscle was remarkably dwindled which was caused by 5-Hydroxytryptamine.

• The Journal of Internal Korean Medicine
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• v.13 no.1
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• pp.99-109
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• 1992

In order to study the effects of Yunpaejaesueum known clinically for their effects of treatment for cough and asthma, the study was carried out to investigate the effect of Yunpaejaesueum extract on the contractile force of the isolated guinea pig trachea smooth muscle and elucidate its mechanism. The results were obtained as follows: 1. The isolated trachea smooth muscle of guinea pig was suspended in the organ bath with oxygenated Kreb's Henseleite bicarbonate buffer solution at $37^{\circ}C$, and the developed tension by the drug was recorded with isometric transducer(Nacro F-60). The resting tension was approximately 0.5g. 2. The isolated trachea smooth muscle of guinea pig was remakably relaxed by the administration of Yunpaejaesueum. 3. Yunpaejaesueum is significantly inhibited the contractile response of histimine 10-4 M in isolated guinea pig trachea smooth muscle. 4. Yunpaejaesueum is significantly inhibited the contractile response of acetylcholine 10-4 M in isolated guinea pig trachea smooth muscle. 5. Yunpaejaesueum is significantly inhibited the contractile response of 5-hydroxytryptamine 10-4 M in isolated guinea pig trachea smooth muscle. 6. Yunpaejaesueum is significantly inhibited the contractile response of prostaglandin F2a 10-7 M in isolated guinea pig trachea smooth muscle.

• The Journal of Internal Korean Medicine
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• v.13 no.1
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• pp.34-45
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• 1992

This study was carried out to investigate the effect of Shihogigiltang extract on the contractile force of the isolated guinea pig trachea smooth muscle and elucidate its mechanism. The results were obtained as follows: 1. The isolated trachea smooth muscle was suspended in the organ bath with oxygenated Kreb's Henseleit bicarbonate buffer solution at $37^{\circ}C$, and the developed tension by the drug was recorded with isometric transducer(Nacro F-60). The resting tension was approximately 0.5g. 2. The trachea smooth muscle of the isoiated guinea pig was significantly relaxed by the administration of Shihogigiltang extract. 3. ShihogigiItang significantly inhibited the contractile response of histamine 10-4 M is isolated guinea pig trachea smooth muscle. 4. The contractile response of the trachea smooth muscle of the isolated guinea pig by acetylcholine 10-4 M was significantly inhibited by Shihogigiltang extract. 5. The contractile response of the trachea smooth muscle of the isolated guinea pig by 5-hydorxytryptamine 10-4 M was significantly inhibited by Shihngigiltang extract. 6. The contractile response of the trachea smooth muscle of the isolated guinea pig by prostaglandin $F2\;{\alpha}$ 10-7 M was significantly inhibited by Shihngigiltang extract.

• Biomolecules & Therapeutics
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• v.13 no.3
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• pp.181-184
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• 2005

The solution-phase combinatorial synthesis of iminodiacetic acid triamide libraries linked to 1-(4-chlorobenzhydryl)piperazine has been reported. Ten mixture libraries, each containing 5 components, were synthesized in 4 steps from N-BOC-iminodiacetic acid anhydride. Antibradykinin effects of the mixture and individual libraries were compared using guinea-pig ileum smooth muscle. The changes in the inhibition were also observed by testing the combination of two different compounds from the same library. We found out the correlation between the inhibition of mixtures and that of individual libraries. It is possible to choose the mixtures with relatively high inhibitory effects to find out the most effective individual compound for further synthesis.