• The Korean Journal of Physiology
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• v.23 no.1
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• pp.99-108
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• 1989

The effects of prostaglandin $(PGF_{2{\alpha}})$ on the contractility of vascular smooth muscle were investigated in the helical strip of the rabbit aorta. The aortic strip was immersed in the phosphate-buffered Tyrode's solution which was equilibrated with 100% $O_{2}$ at $35^{\circ}C$ and its isometric tension was measured. The contraction was induced by $(PGF_{2{\alpha}})$, norepinephrine (NE), or potassium (40 mM) in the nomal Tyrode's solution (1 mM, $Ca^{2+}$) or $Ca^{2+}-free$ Tyrode's solution. Effects of verapamil and phentolamine on the contraction were also observed. The aortic strip began to contract at the concentration of $5\;{\mu}g%$ and reached the maximal contraction at the concentration of $150\;{\mu}g%$ $(PGF_{2{\alpha}})$. The maximal contraction was corresponded respectively to $52.2{\pm}3.0%$ and $81.5{\pm}3.5%$ of maximal contraction by NE $(1{\times}10^{-5}M)$ and 40 mM $K^{+}$. And the maximal contractions by $(PGF_{2{\alpha}})$ or NE were induced at the concentration of about 1 mM $Ca^{2+}$. $(PGF_{2{\alpha}})$ induced the contraction of aortic strip even after induction of contraction by 40 mM $K^{+}$ and the contraction by $(PGF_{2{\alpha}})$ was not blocked by the ${\alpha}-receptor$ blocker, phentolamine. And the contraction by the $(PGF_{2{\alpha}})$ was inhibited partially by a verapamil at the concentration of $1{\times}10^{-5}M$ and the contraction began to increase at the concentration of $1{\times}10^{-4}M$ verapamil. Whereas the contraction by NE was completely blocked by verapamil. Though both the $(PGF_{2{\alpha}})$ and NE induced the contraction in the $Ca^{2+}-free$ Tyrode's solution, the peak tension was not maintained. But the rate of tension decline was lower in the contraction by $(PGF_{2{\alpha}})$ than in that by NE. The verapamil did not inhibit the contraction by $(PGF_{2{\alpha}})$ in the $Ca^{2+}-free$ Tyrode's solution and increased the contraction at the concentration of above $1{\times}10^{-4}M$. The NE-induced contraction in the $Ca^{2+}-free$ Tyrode's solution was inhibited completely by a verapamil. From the above results it is suggested that the contraction induced by $(PGF_{2{\alpha}})$ results from the promotion of the both $Ca^{2+}$ influx and the intracellular $Ca^{2+}$ release by different way from NE.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.617-622
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• 1993

The preliminary studies on the localization of adrenoceptors were performed on smooth muscle strips of bovine esophageal groove. The mechanical activity of the muscle strip was recorded isometrically in vitro.w In the bottom circular muscle strips. the excitatory ${\alpha}-adrenergic$ responses were not blocked by tetrodotoxin$(2.1{\times}10^{-6}M)$ and denervation which was carried by cold storage of strips for 48 hrs in Tyrode's solution at $5-6{^{\circ}C}$ without oxygen supply. These excitatory ${\alpha}-adrenergic$ responses were partially blocked by atropine. In the lip longitudinal muscle strips, the inhibitory${\beta}-adrenergic$ responses were not blocked by pretreatment of tetrodotoxin and atropine. The results suggest that ${\beta}-adrenergic$ receptors mediating relaxations are located on the postsynaptic smooth muscle cells, whereas ${\beta}-adrenergic$ receptors mediating contractions are located both in the smooth muscle cells and in the cholinergic neurones.

• International Journal of Aeronautical and Space Sciences
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• v.3 no.2
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• pp.46-58
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• 2002

An inverse method is introduced to construct benchmark problems for the numerical solution of initial value problems. Benchmark problems constructed through this method have a known exact solution, even though analytical solutions are generally not obtainable. The solution is constructed such that it lies near a given approximate numerical solution, and therefore the special case solution can be generated in a versatile and physically meaningful fashion and can serve as a benchmark problem to validate approximate solution methods. A smooth interpolation of the approximate solution is forced to exactly satisfy the differential equation by analytically deriving a small forcing function to absorb all of the errors in the interpolated approximate solution. A multi-variable orthogonal function expansion method and computer symbol manipulation are successfully used for this process. Using this special case exact solution, it is possible to directly investigate the relationship between global errors of a candidate numerical solution process and the associated tuning parameters for a given code and a given problem. Under the assumption that the original differential equation is well-posed with respect to the small perturbations, we thereby obtain valuable information about the optimal choice of the tuning parameters and the achievable accuracy of the numerical solution. Illustrative examples show the utility of this method not only for the ordinary differential equations (ODEs) but for the partial differential equations (PDEs).

• Journal of the Korean Mathematical Society
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• v.52 no.1
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• pp.43-65
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• 2015

We present a new convergence analysis of popular Broyden's method in the Banach/Hilbert space setting which is applicable to non-smooth operators. Moreover, we do not assume a priori solvability of the equation under consideration. Nevertheless, without these simplifying assumptions our convergence theorem implies existence of a solution and superlinear convergence of Broyden's iterations. To demonstrate practical merits of Broyden's method, we use it for numerical solution of three nontrivial infinite-dimensional problems.

• Communications of the Korean Mathematical Society
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• v.28 no.1
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• pp.191-207
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• 2013

In this paper, we introduce the shrinking projection method for hemi-relatively nonexpansive mappings to find a common solution of variational inequality problems and equilibrium problems in uniformly convex and uniformly smooth Banach spaces and prove some strong convergence theorems to the common solution by using the proposed method.

• Bulletin of the Korean Mathematical Society
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• v.57 no.2
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• pp.393-406
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• 2020

We analyze a posteriori error estimator for the conforming P2 finite element on triangular meshes which is based on the solution of local Neumann problems. This error estimator extends the one for the conforming P1 finite element proposed in [4]. We prove that it is asymptotically exact for the Poisson equation when the underlying triangulations are mildly structured and the solution is smooth enough.

• Journal of the Korean Mathematical Society
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• v.31 no.3
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• pp.401-416
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• 1994

We study the existence of an intermediate solution of nonlinear elliptic boundary value problems (BVP) of the form $$ (BVP) {\Delta u = f(x,u,\Delta u), in \Omega {Bu(x) = \phi(x), on \partial\Omega, $$ where $\Omega$ is a smooth bounded domain in $R^n, n \geq 1, and \partial\Omega \in C^{2,\alpha}, (0 < \alpha < 1), \Delta$ is the Laplacian operator, $\nabla u = (D_1u, D_2u, \cdots, D_nu)$ denotes the gradient of u and $$ Bu(x) = p(x)u(x) + q(x)\frac{d\nu}{du} (x), $$ where $\frac{d\nu}{du} denotes the outward normal derivative of u on $\partial\Omega$.

• Journal of Surface Science and Engineering
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• v.28 no.2
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• pp.101-109
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• 1995

Electroetching rates of $FeCl_3$ solution were increased according to increasing solution temperature. Activation energy of electroetching at Be'36 and 5A/$dm^2$ condition was 28.3Kcal and also, at Be'46 and 5A/dm$^2$ condition was 33.2Kcal. At Be'36 concentration of $FeCl_3$ solution, electroetching rate were more higher than at Be'46 concentration. Surfaces of etched grooves obtained at 8A/$dm^2$ or higher current density in 46 Be' concentration of $FeCl_3$ solution were observed to be flat and smooth owing to suppressing chemical etching reaction. Distinctly etched boundaries became to be appeared at 2A/$dm^2$ in Be'41 electroetching condition by differential effects. In case of applying 8A/$dm^2$ current density to Be'46 of $FeCl_3$ solution, etching depth were 4 times and side etching were 6 times more than chemical etching case respectively.

• Progress in Superconductivity
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• v.12 no.2
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• pp.118-123
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• 2011

The properties of $2^{nd}$ generation high temperature superconducting wire, coated conductor strongly depend on the quality of superconducting oxide layer and property of metal substrate is one of the most important factors affecting the quality of coated conductor. Good mechanical and chemical stability at high temperature are required to maintain the initial integrity during the various process steps required to deposit several layers consisting coated conductor. And substrate need to be nonmagnetic to reduce magnetization loss for ac application. Hastelloy and stainless steel are the most suitable alloys for metal substrate. One of the obstacles in using stainless steel as substrate for coated conductor is its difficulties in making smooth surface inevitable for depositing good IBAD layer. Conventional method involves several steps such as electro polishing, deposition of $Al_2O_3$ and $Y_2O_3$ before IBAD process. Chemical solution deposition method can simplify those steps into one step process having uniformity in large area. In this research, we tried to improve the surface roughness of stainless steel(SUS310). The precursor coating solution was synthesized by using yttrium complex. The viscosity of coating solution and heat treatment condition were optimized for smooth surface. A smooth amorphous $Y_2O_3$ thin film suitable for IBAD process was coated on SUS310 tape. The surface roughness was improved from 40nm to 1.8 nm by 4 coatings. The IBAD-MgO layer deposited on prepared substrate showed good in plane alignment(${\Delta}{\phi}$) of $6.2^{\circ}$.

• Journal of the Korean Mathematical Society
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• v.33 no.1
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• pp.31-38
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• 1996

It is well known that Dirichlet problem of the first-order Hamilton-Jacobi equations $$ (H-J) u(x) + H(\nabla u(x)) = f(x), x \in R^N, $$ does not have a classical solution even though the Hamiltonian H is smooth.