• 한국수학교육학회지시리즈A:수학교육
• /
• 제19권2호
• /
• pp.19-22
• /
• 1981

• 대한후두음성언어의학회지
• /
• 제9권2호
• /
• pp.152-155
• /
• 1998

Laryngeal framework surgery to improve change the voice is a challenging development in phoniatric surgery. Basically two categories can be distinguished : (1) attempted medialization of the vocal fold, as for the treatment of paralytic dysphonias (2) adjustment of the vocal fold's tension of transsexuals or mutational dysphonia. Vocal pitch can be elevated by various surgical technique 1) cricothyroid approximation 2) A-P expansion of the thyroid ala 3) longitudinal incision in the cords 4) intrachondral injection of the steroid, and 5) evaporation of the cords by $CO_2$ laser. We have experienced a case of pitch elevation procedure after transsexual operation. After transsexual operation, he had received anterior commissure laryngoplasty modified from Le Jeune with no change in voice pitch(Fo=110Hz). 8 monthes later, he had received cricothyroid approximation resulting in pitch elevation(Fo=160Hz).

• Structural Engineering and Mechanics
• /
• 제73권1호
• /
• pp.1-16
• /
• 2020

Finite elements based on the partition of unity (PU) approximation have powerful capabilities for p-adaptivity and solutions with high smoothness without remeshing of the domain. Recently, the PU approximation was successfully applied to the three-node shell finite element, properly eliminating transverse shear locking and showing excellent convergence properties and solution accuracy. However, the enrichment with the PU approximation results in a significant increase in the number of degrees of freedom; therefore, it requires greater computational cost, thus making it less suitable for practical engineering. To circumvent this disadvantage, we propose a new strategy to decrease the total number of degrees of freedom in the existing PU-based shell element, without loss of optimal convergence and accuracy. To alleviate the locking phenomenon, we use the method of mixed interpolation of tensorial components and perform convergence studies to show the accuracy and capability of the proposed shell element. The excellent performances of the new shell elements are illustrated in three benchmark problems.

• Journal of the Korean Physical Society
• /
• 제73권11호
• /
• pp.1612-1618
• /
• 2018

In this work, the ground-state properties of an interacting electron gas confined in a two-dimensional quantum dot system with the Gaussian potential ${\upsilon}(r)=V_0(1-{\exp}(-r^2/p))$, where $V_0$ and p are confinement parameters, are determined numerically by using the Thomas-Fermi approximation. The shape of the potential is modified by changing the $V_0$ and the p values, and the influence of the confining potential on the system's properties, such as the chemical energy, the density profile, the kinetic energy, the confining energy, etc., is analyzed for both the non-interacting and the interacting cases. The results are compared with those calculated for a harmonic potential, and excellent agreement is obtained in the limit of high p values for both the non-interacting and the interacting cases.

• Interaction and multiscale mechanics
• /
• 제1권4호
• /
• pp.423-435
• /
• 2008

This paper employs the reproducing kernel (RK) approximation for evaluation of field theory-based incompatibility tensor in a polycrystalline plasticity simulation. The modulation patterns, which is interpreted as mimicking geometrical-type dislocation substructures, are obtained based on the proposed method. Comparisons are made using FEM and RK based approximation methods among different support sizes and other evaluation conditions of the strain gradients. It is demonstrated that the evolution of the modulation patterns needs to be accurately calculated at each time step to yield a correct physical interpretation. The effect of the higher order strain derivative processing zone on the predicted modulation patterns is also discussed.

• 대한전자공학회논문지
• /
• 제18권5호
• /
• pp.1-9
• /
• 1981

4-bit 전하결합 A/D 변환기에 대한 실험 결과를 제시하였다. Successive approximation algorithm 에 필요한 대개의 기능을 CCADC(charge coupled A/D converter)라는 mono-lithiic chip으로 실현하였다. CCADC는 P-channel 전하결합소자 제작기술에 의하여 만들어졌으며, Chip면적은 약 4,200 $mil^2$이었다. 동작 clock 주파수 범위는 500Hz ~ 200KHz로 나타났으며, 이 주파수 범위내에서는 약 2.4 Volt의 전신호 전압 구간을 1LSB/clok주기의 속도로 변하는 ramp 입력신호에 대하여 16가지의 binary code가 빠짐없이 관찰되었다. MSB단부터 LSB단의 순서로 정격 전하용량이 각각 3.6pC, 1.8pC, 0.9pC, 0.45pC인 4개의 연속된 potential well(M-well)간의 면적비를 (8:4:2:1)로 유지하기 위한 설계기술에 대하여 토론하였다. 끝으로, 제작된 A/D변환기에 있어서 과도한 conversion nonlinearity의 원인이 되는 dumpslot 효과에 대하여 설명하였으며, dump slot으로 인한 오동작을 막기 위한 방법으로서 slot zero 삽입방식을 제안하고 이에 대한 실험결과를 제시하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제4권1호
• /
• pp.67-77
• /
• 2000

In this paper we consider finite element mathods for nonlinear parabolic problems defined in ${\Omega}{\subset}R^d$ ($d{\leq}4$). A new initial approximation is taken. Optimal order error estimates in $L_p$ for $2{\leq}p{\leq}{\infty}$ are established for arbitrary order finite element. One order superconvergence in $W^{1,p}$ for $2{\leq}q{\leq}{\infty}$ are demonstrated as well.

• 대한화학회지
• /
• 제16권3호
• /
• pp.119-134
• /
• 1972

Various MO methods with differing degrees of sophistication are shown to yield qualitatively consistent results for methyl isoalloxazins. However, with crude methods such as the HMO and ${\omega}$-technique, the choice of Coulomb and resonance integralsis critical, in contrast with simpler molecular systems. The empirical value of ${\omega}$=0.5 appears to be more reasonable than 1.4. Methyl groups in these flaving are best treated by the group orbital approximation. The pseudo-heteroatom approximation overestimates methyl hyperconfiguration with the Pariser-Parrpole SCR MO method. siglet ${\pi}{\rightarrow}{\pi}^*$ transition energies are calculated by the P-P-P method and agree reasonably with the experimental values. 2- and 4-Thioisoalloxazine analogs are also treated. Reactivity indices of the flavin molecule are presented, includeing superdelocalizability. frontier orbital and radical densities. Various aspects of the applications of these indices of the methyl groups on dipolemoments, inozation potentialsm elctron affinities, and spectra are decribed in detail.

• 설비공학논문집
• /
• 제4권1호
• /
• pp.20-32
• /
• 1992

A numerical solution for heat transfer in the flue tube of a pulse combustion water heater was presented. The $k-{\varepsilon}$ turbulent model was adopted to describe turbulent characteristics and radiative heat transfer was calculated by P-N approximation. Three pulsating conditions equivalent to existing experimental studies were used for analysis. Pulsating pressure was specified at the inlet and outlet of flue tube and numerical procedure using control volume method and pressure boundary condition was presented. It was found that the present mathematical model and numerical method could predict effectively the flow field and heat transfer for the flue tube in pulse combustor.

• Journal of Mechanical Science and Technology
• /
• 제16권12호
• /
• pp.1725-1732
• /
• 2002

Combined convection and radiation heat transfer in a circular tube with circumferential fins and circular disks is investigated for various operating conditions. Using a finite volume technique for steady laminar flow, the governing equations are solved in order to study the flow and temperature fields. The P- 1 approximation and the weighted sum of gray gases model (WSGGM) are used for solving the radiation transport equation. The results show that the total Nusselt number of combined convection and radiation is higher than that of pure convection. If the temperatures of the combustion gas and the wall in a tube are high, radiation becomes dominant. Therefore, it is necessary to evaluate the effect of radiation on the total heat transfer.