• Journal of applied mathematics & informatics
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• 제3권2호
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• pp.245-252
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• 1996

We described a relationship of the $L_2$ norm of the $L_2$norm of a Bzier curve and l2 norm of its confrol points. The use of Bezier curves finds much application in the general description of curves and surfaces and provided the mathematical basis for many computer graphics system. We define the $L_2$ norm for Bezier curves and find a upper and lower bound for many computer graphics system. We define the $L_2$ norm for Bezier curves and find a upper and lower bound for the $L_2$ norm with respect to the $L_2$ norm for its control points for easy computation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.151-153
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• 2002

Using UPFC(Unified Power Flow Controlled), it is possible to control three parameters(voltage, impedance, and phase angle). The UPFC can generate or absorb reactive power rapidly so as to enhance the transient and voltage stability and also influence the power flow. In this paper, the effects of application of the UPFC to the power system are analyzed from a viewpoint of improving the total transfer capability by enhancing voltage stability. The IPLAN, which is a high level language used with PSS/E program, is employed for evaluating the total transfer capability from a f-V curve.

• Journal of Plant Biology
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• 제36권1호
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• pp.59-66
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• 1993

In maize coleoptile segments where auxin transport capacity decreases with time following excision, susceptability of the tissue to transport inhibitors such as N-1-naphthylphthalamic acid (NPA), 3,4,5-triiodobenzoic acid (TIBA) or high concentrations of IAA was found to be rather increased. A time-dependent increase in the sensitivity to NPA can be postulated since the dose-response curve for NPA was shifted in the‘aged’tissue to the left (i.e. lower concentration). Preincubation of the tissue at a low temperature abolished the time-dependent sensitivity change, suggesting that cellular metabolism could be involved. The NPA-sensitive state was also brought about by calcium depletion of the tissue, which can be partially reversed by addition of calcium. Presence of exogenous IAA in the preincubation medium kept the auxin transport system from decay, implicating auxin as an endogenous controlling factor. Results of our experiments indicate a reversible, time-dependent changes of auxin transport system in which transport capacity and sensitivity to NPA are tightly coupled. Changes in the sensitivity to NPA were also seen in auxin action as well.

• 한국자기학회지
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• 제5권5호
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• pp.767-771
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• 1995

The atomic structure and magnetic properties of $LaCo_{13}$ amorphous alloy have been investigated and compared with those of its crystalline counterpart. It has been confirmed that the amorphous alloy is composed of the icosahedral clusters with a $NaZn_{13}$-type structure. The magnetic moment and the spin- wave stiffness constant obtained from the magnetic measurements in the amorphous state are larger than those in the crystalline state. The Curie temperature estimated from the reduced magnetization curve for the former is much higher than the value for the latter. The localized magnetic moment character in the amorphous state is stronger than that in the crystalline state.

• 펄프종이기술
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• 제41권5호
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• pp.59-65
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• 2009

Adsorption of an oil-proof agent (OPA）onto cellulose fibers during the papermaking process was investigated using UV-Vis spectrophotometry by measuring the OPA concentration decrease in the solution. From the calibration curve, the spectrum were converted to chemical concentrations in solution, from which the amount adsorbed onto the fiber surface could be determined. Thus, it was possible to determine the total amount adsorbed onto the fibers and in solution. Using this approach, we studied the adsorption behavior of the OPA onto the fiber surface and derived its, ${\Gamma}^s_t={\Gamma}^s_{\infty}(1-e^{-k_{\alpha}t})$. The values of the parameters kaand ${\Gamma}^s_{\infty}$ were determined using a mathematic model based on a mass transfer equation. Ultimately, a complete was derived: $Q={\alpha}{\cdot}\sum\limits_{i-1}^m{\pi}d_il_i{\cdot}M_A{\cdot}(1-e^{-k_{\alpha}t})/A_N$.

• 한국안광학회지
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• 제12권1호
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• pp.85-90
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• 2007

안경렌즈의 무반사 코팅물질로 사용되는 황화아연(Zinc Sulphide : ZnS)의 단일박막을 실리콘과 슬라이드 유리 기판위에 스핀코팅방법으로 증착하였다. 박막 증착 후 변입사각분광타원계(VASE : Variable Angle Spectroscopic Ellipsometer)를 사용하여 1.5~5.0 eV 광 에너지 영역에서 타원 각(ellipsometry angle) ${\Delta}$, ${\Psi}$를 측정하였다. 이 측정결과들을 Jellison Modine 분산관계식을 사용하여 최적맞춤하고, 매개변수들을 구하여 박막의 광학상수인 굴절계수 $n({\lambda})$와 소광계수 $k({\lambda})$를 결정하였다.

• E2M - 전기 전자와 첨단 소재
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• 제8권2호
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• pp.171-175
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• 1995

Optimum condition of remote plasma enhanced chemical vapor deposition using orthogonal array method was chosen. Characteristics of oxide films deposited by RPECVD with SiH$_{4}$ and N$_{2}$O gases were investigated. Etching rate of the optimized SiO$_{2}$ films in P-etchant was about 6[A/s] that was almost the same as that the high temperature thermal oxide. The films showed high dielectric breakdown field of more than 7[MV/cm] and a resistivity of 8*10$^{13}$ [.ohmcm] around at 7[MV/cm]. The interface trap density of SiO$_{2}$/Si interface around the midgap derived from the high frequency C-V curve was about 5*10$^{10}$ [/cm$^{2}$eV]. It was observed that the dielectric constant of the optimized SiO$_{2}$ film was 4.29.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.805-814
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• 2008

This study focused on the resilient modulus prediction model, which is the functions of mean effective principal stress and axial strain, for three types of railroad trackbed materials such as crushed stone, weathered soil, and crushed-rock soil mixture. The model is composed with the maximum Young's modulus and nonlinear values for higher strain in parallel with dynamic shear modulus. The maximum values is modeled by model parameters, $A_E$ and the power of mean effective principal stress, $n_E$. The nonlinear portion is represented by modified hyperbolic model, with the model parameters of reference strain, ${\varepsilon}_r$ and curvature coefficient, a. To assess the performance of the prediction models proposed herein, the elastic response of a test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement during the passages of freight and passenger trains. The material types of sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 0.6mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation.

• Steel and Composite Structures
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• 제32권2호
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• pp.199-212
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• 2019

This paper presents an investigation on seismic behavior of out-of-code Q690 circular high-strength concrete-filled thin-walled steel tubular (HCFTST) columns made up of high-strength (HS) steel tubes (yield strength $f_y{\geq}690MPa$). Eight Q690 circular HCFTST columns with various diameter-to-thickness (D/t) ratios, concrete cylinder compressive strengths ($f_c$) and axial compression ratios (n) were tested under the constant axial loading and reversed cyclic lateral loading. The obtained lateral load-displacement hysteretic curves, energy dissipation, skeleton curves and ductility, and stiffness degradation were analyzed in detail to reflect the influences of tested parameters. Subsequently, a simplified shear strength model was derived and validated by the test results. Finally, a finite element analysis (FEA) model incorporating a stress triaxiality dependent fracture criterion was established to simulate the seismic behavior. The systematic investigation indicates the following: compared to the D/t ratio and axial compression ratio, improving the concrete compressive strength (e.g., the HS thin-walled steel tube filled with HS concrete) had a slight influence on the ductility but an obvious enhancement of energy dissipation and peak load; the simplified shear strength model based on truss mechanism accurately predicted the shear-resisting capacity; and the established FEA model incorporating steel fracture criterion simulated well the seismic behavior (e.g., hysteretic curve, local buckling and fracture), which can be applied to the seismic analysis and design of Q690 circular HCFTST columns.

• 한국지반공학회논문집
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• 제26권9호
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• pp.5-13
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• 2010

최근 초고층 빌딩과 대형 교량의 사용 증가로 인하여 바렛말뚝에 대한 사용이 증가하고 있지만 바렛말뚝의 주면부 거동특성에 대한 연구는 미비한 실정이다. 이에 본 연구에서는 실물크기 시험말뚝에 대한 현장재하시험을 실시하여 표준관입시험 저항치와 바렛말뚝의 주면히중전이곡선을 산정하는 경험식을 제안하였다. 또한 3차원 유한요소해석을 실시하여 말뚝과 지반과의 경계면 효과를 살펴보았으며 이를 현장자료와 비교하여 평가하였다.