• 대한수학회지
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• 제48권5호
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• pp.1017-1041
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• 2011

The parabolic Bergman space is the set of $L^p(\lambda)$-solution of the parabolic operator $L^{(\alpha)}$. In this paper, we study representin sequences on parabolic Bergman spaces. We establish a discrete version of the reproducing formula on parabolic Bergman spaces by using fractional derivatives of the fundamental solution of the parabolic operator.

• 한국경영과학회지
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• 제30권1호
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• pp.177-185
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• 2005

We consider the optimization problem of the geostationary satellite orbital positions. which is very fundamental and important in setting up the new satellite launching plan. We convert the problem into a discrete optimization problem. However, the converted problem is too complex to find an optimal solution. Therefore, we develope the solution procedures using simulated annealing technique. The results of applying our method to some examples are reported.

• 대한전자공학회논문지
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• 제25권2호
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• pp.130-138
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• 1988

The method of conjugate gradient (C.G.M.) is applied to the solution of current distribution from body of revolution(B.O.R.). Using the C.G.M., it is possible to analyze electrically large arbitratily oriented B.O.R.. The fundamental differencess between C.G.M. and moment are outlined. This method converge for any initial guess, and this techniqe guarantees a monotonic convegence. Numerical resulsts are presented for electromagnetic case which shows good agreements with moment solution.

• Structural Engineering and Mechanics
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• 제10권5호
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• pp.441-449
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• 2000

In this study, the state equation for axisymmetric bending of laminated transversely isotropic circular plates on elastic foundation is established on the basis of three-dimensional elasticity. By using the expansions of Bessel functions, an analytical solution of the problem is presented. As a result, all the fundamental equations of three-dimensional elasticity can be satisfied exactly and all the independent elastic constants can be fully taken into account. Furthermore, the continuity conditions at the interfaces of plies can also be satisfied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.113-115
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• 1998

This paper presents the indirect boundary integral equation method(BIEM) to analyze 3D moving conductor problem. Instead of an artificial upwind algothm, the proposed method uses a fundamental Green's function which is a particular solution of diffusion equation. Therefore, this method yields a stable and accurate solution regardless of the Peclet number. The indirect BIEM is compared with 3D upwind FEM for a numerical model which has analytic solutions.

• 한국표면공학회지
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• 제25권3호
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• pp.117-125
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• 1992

In the electrolysis process of zinc plating impurity ions must be removed from zinc chloride plating solution because it's harmful to the current efficiency and the purity of zinc plating. In this study using zinc ball as a prcipitant instead of zinc dust, the fundamental data for continuous cementation process was studied. Based upon two series of experiments that consist of batch experiment with cylindrical zinc specimen and continuous experiment with zinc balls, following results have been obtained. In the continuous experiment all impurity ions have been removed within 1 hour regardless of various experimental conditions.

• 한국수산과학회지
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• 제29권6호
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• pp.843-848
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• 1996

As the first step of studies related to production of chitooligosaccharides by physical methods, chitosan solution were sonicated with 20 kHz and various treatment effects were examined to present fundamental data of sonicated chitosan solution. Intrinsic viscosity of chitosan solution sharply decreased from 3.76 dl/g to 2.90 dl/g until 5 minutes of sonication and then slowly decreased. With low volume of chitosan solution, sonication was very effective and temperature of chitosan solution slightly affected the efficiency of sonication. In case of changing the solvent, no significant differences were observed on the effect of sonication, however, acetate buffer had highest sonication effect among various solvents. The sonication effect was increased as the increasement of the value of pH, on the contrary, ionic strength and type of counterions showed no effect on sonication. With these results, we assumed that optimal sonication treatment would be as follows, solution volume was $10\~20\;ml$, temperature range was $20\~30^{\circ}C$, pH value of solution was 4.5 and type of solvent was acetate buffer.

• Structural Engineering and Mechanics
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• 제67권3호
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• pp.255-265
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• 2018

The prestress force effect on the fundamental frequency and deflection shape of Prestressed Concrete I (PCI) beams was studied in this paper. Currently, due to the conflicts among existing theories, the analytical solution for properly considering the structural behavior of these prestressed members is not clear. A series of experiments were conducted on a large-scale PCI beam of high strength concrete with an eccentric straight unbonded tendon. Specifically, the simply supported PCI beam was subjected to free vibration and three-point bending tests with different prestress forces. Subsequently, the experimental data were compared with analytical results based on the Euler-Bernoulli beam theory. It was proved that the fundamental frequency of PCI beams is unaffected by the increasing applied prestress force, if the variation of the initial elastic modulus of concrete with time is considered. Vice versa, the relationship between the deflection shape and prestress force is well described by the magnification factor formula of the compression-softening theory assuming the secant elastic modulus.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1698-1711
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• 2024

Heat pipe cooled reactors have gained attention as a potential solution for nuclear power generation in space and deep sea applications because of their simple design, scalability, safety and reliability. However, under complex operating conditions, a control strategy for variable load operation is necessary. This paper presents a two-dimensional transient characteristics analysis program for a heat pipe cooled reactor and proposes a variable load control strategy using the recuperator bypass (CSURB). The program was verified against previous studies, and steady-state and step-load operating conditions were calculated. For normal operating condition, the predicted temperature distribution with constant heat pipe temperature boundary conditions agrees well with the literature, with a maximum temperature difference of 0.4 K. With the implementation of the control strategy using the recuperator bypass (CSURB) proposed in this paper, it becomes feasible to achieve variable load operation and return the system to a steady state solely through the self-regulation of the reactor, without the need to operate the control drum. The average temperature difference of the fuel does not exceed 1 % at the four power levels of 70 %,80 %, 90 % and 100 % Full power. The output power of the turbine can match the load change process, and the temperature difference between the inlet and outlet of the turbine increases as the power decreases.

• 대한기계학회논문집
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• 제19권4호
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• pp.981-989
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• 1995

A new weight function approach to determine SIF(stress intensity factor) using single-layer potential has been presented. The crack surface displacement field was represented by one boundary integral term whose kernel was modified from Kelvin's fundamental solution. The proposed method enables the calculation of SIF using only one SIF solution without any modification for the crack geometries symmetric in two-dimensional plane such as a center crack in a plate with or without an internal hole, double edge cracks, circumferential crack or radial cracks in a pipe. The application procedure to those crack problems is very simple and straightforward with only one SIF solution. The necessary information in the analysis is two reference SIFs. The analysis results using present closed-form solution were in good agreement with those of the literature.