• 한국안전학회지
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• 제9권2호
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• pp.3-11
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• 1994

This study discribes result of comparision of two other numerical method, method of characteristics (MOC) and Lax-Wendroff method(LWM) applied at wave action analysis of Intake and exhaust pipe. Partiality FCT(Flux Correct Transport) scheme is appeneded to LWM to protest unacceptable overshoots, occuring near discontinuity. The final conclusion of this study is that MOC should be replaced by a second order finite difference approach(such as the LW method). Clear benefits we can get by change are faster calculation, higher accuracy, conservation of mass and consistent calculation method.

• 열처리공학회지
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• 제11권1호
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• pp.27-34
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• 1998

Effects of different heat treatments on microstructure and damping capacity of Cu-55%Mn alloy were investigated to find an optimum heat treatment condition for a maximum damping capacity. The alloy showed the high level of damping capacity in case of the aging at 375 and $400^{\circ}C$. This is ascribed to the FCC${\rightarrow}$FCT martensitic transformation and microstructural changes from mottled to tweed band type. The damping capacity had a maximum value of 0.33 in logarithmic decrement when the alloy was aged at $375^{\circ}C$ for 14 hours followed by 20 times of thermal cycling between room temperature and $250^{\circ}C$. The refinement of tweed structure by thermal cycling is thought to be responsible for the highest damping capacity.

• 한국전기전자재료학회논문지
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• 제21권4호
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• pp.381-387
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• 2008

Neutron production rate in spherically convergent beam fusion(SCBF) device as a portable neutron source strongly depends on the ion current and the grid cathode structure. In this paper, as the process of design and analysis, Design of Experiment(DOE) based on the results by Finite Element Method-Flux Corrected Transport(FEM-FCT) method is employed to calculate the ion current. This method is very useful to find optimal design conditions in a short time. Number of rings, radius of rings, and distance between the grid cathode and center are selected as control factors. From the results in the optimized model, the higher ion current is calculated and deeper potential well is also observed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1834-1836
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• 1997

In this study, we simulated the developing process of two-dimensional corona discharge using the fluid method in 760 torr. It was assumed that the transport coefficients of nitrogen gas were only the function of local electric field. Discharge mechanisms considered were a Townsend first ionization and a secondary electron emission. We obtained spatio-temporal distribution of electron and ion by calculating continuity equation using FCT algorithm and calculated an electric field distribution considering a space charge.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.76-83
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• 1995

Estimation of blasting behavior of explosives is prerequisite in the numerical analysis of blasting works. In this study, blasting pressure is estimated by the finite difference method using the Flux-Corrected Transport Algorithm. To formulate the behavior of blasting gas, the mass conservation equation, the moment conservation equation, the energy conservation equation and the ideal gas state equation are used. The simplified species conservation equation is included to simulate the behavior of reacting explosives. To verify the calculation, the Sod's shock tube problem, the strong shock problem and the reacting problem we used. Numerical results show that the shock wave can be captured by means of the FCT algorithm in the reacting and nonreacting states.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 춘계학술발표회논문집(2)
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• pp.603-608
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• 1995

핵연료 성능과 uranium loading 향상을 위하여 제조한 $U_3$Si ribbon은 초정 $U_3$S $i_2$와 uranium solid solution으로 이루어져 있으며, 잘 발달된 dendrite 조직을 이루고 있다. 또한 grain size는 종전 ingot 제조방법에 비하여 약 1/20 정도로 미세하다. $700^{\circ}C$와 80$0^{\circ}C$에서 열처리한 $U_3$Si grain 내 twinning 현상은 이 온도구간에서 ordering 변태가 일어나는 것을 나타내며, TEM electron diffraction pattern 분석결과 twin은 {011}$_{fct}$ twin Plane을 따라 일어나는 것을 확인하였다.다.

• 전자공학회논문지S
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• 제35S권4호
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• pp.20-29
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• 1998

In this paper, we find the values of near-end crosstalk coefficients in dual-offset stripline of a FR-4 multilayer PCB by an analytic method and a HSPICE simulation method, define calculation errors inananlytic method and the application range, simulate near-end crosstalk coefficients of the FCT(Fast CMOS TTL) in complicated dual-offset stripline by HSPICE and analyze near-end crosstalk and far-end crosstalk coefficients in dual-offset stripline. So, we analyze coupling structure of the near-end crosstalk and far-end crosstalk in the complicated dual-offset striplines that are 1[pF] capacitors termainated, and define a coupling formula of near-end crosstalk and far-end crosstalk coefficients dual-offset striplines.

• 천문학논총
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• 제11권1호
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• pp.91-107
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• 1996

We determine analytically the onset of thin-shell formation time of fast wind bubble with power-law energy injection $E_{in}=E_0t^s$, and power-law ambient density structure, ${\rho}_0(r)={\bar{\rho}}(r/{\bar{r}})^{-{\omega}}$. Thin-shell formation time, $t_{sf}$ can be estimated by minimizing the total time elapsed before the complete cooling of shocked gas. For uniform medium (${\omega}=0$) and constant energy injection (s = 1), the onset of shell formation is found to be at $t_{sf}=5.2{\times}10^3yr$, which agrees Quite well with the results of FCT 1D numerical calculation. We solve the line transfer problem with previous result derived by numerical calculation in order to calculate line profile of [OIII] (${\lambda}=5007{\AA}$) forbidden line. In general, radiative outer shell causes the formation of double peaked line profile. Each peak corresponds to approaching and receeding shells with large velocities. Our line profiles show good agreements with observation of expanding shell structure.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권5호
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• pp.232-237
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• 2001

The transition avalanche to streamer are presented in atmospheric pressure nitrogen. The results of two-dimensional simulation are obtained by using finite Elements Method combined with Flux Corrected Transport algorithm(FEM-FCT). We modeled the negative streamer which enables to propagate with out and with photoionization. The results of simulation without photoionization and with photoionization are compared. We show that photoionization plays important roles not only in streamer formation but also in streamer propagation.

• 한국전기전자재료학회논문지
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• 제13권3호
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• pp.265-272
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• 2000

In this paper the corona discharge in SF$_{6}$ gas used as insulating material in lots o high voltage equipment, is simulated by finite element method with Flux-Corrected Transport(FCT) method. By application of proposed method the negative corona discharge characteristics in needle to plane electrode is analyzed with time step. For the accuracy of analysis the secondary electron emission by photon and ion are also considered as well as the accuracy of analysis the secondary electron emission by photon and ion are also considered as well as townsend first ionization and electron attachment. The calculated results show that the electric field intensity between anode and ion group is decreased as times go-by according to field distortion by those space charge. Accordingly the electron density is decreased strongly by the attatchment effect of SF6 gas so that the corona discharge becomes extinguished abruptly.y.