• 약학회지
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• 제49권1호
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• pp.1-5
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• 2005

Near-infrared (NIR) spectroscopy has been widely applied in various field, since it is nondestructive and no sample preparation is required. In this paper, NIR spectroscopy was used for the determination of naproxen in a commercial pharmaceutical preparation. NIR spectroscopy was used to determine the content of naproxen in intact naproxen tablets containing 250 mg ($65.8\%$ nominal concentration) by collecting NIR spectra in the range of $1100{\sim}1750nm$. The laboratory-made samples had $46.1{\sim}85.5\%$ nominal naproxen concentration. The measurements were made by reflection using a fiber-optic probe and calibration was carried out by partial least square regression (PLSR). Model validation was performed by randomly splitting the data set into calibration and validation data set (63 samples as a calibration data set and 42 samples as a validation data set). The developed NIR calibration gave results comparable to the known values of tablets in a laboratorial manufacturing process with standard error of calibration (SEC) and standard error of prediction (SEP) of $1.06\%\;and\;1.04\%$, respectively. The NIR method showed good accuracy and repeatability. NIR spectroscopic determination in intact tablets allowed the potential use of real time monitoring for a running production process.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.532-537
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• 2005

The techniques of internally generating waves on a curve in a rectangular grid system are developed using the line source method. Numerical experiments are conducted using the extended mild-slope equations of Suh et al. (1997). For five different types of wave generation layout, numerical experiments are conducted in the cases of the propagation of waves on a flat bottom, and the refraction and shoaling of waves on a plane slope. The fifth type of wave generation, which consists of two parallel lines connected to a semicircle, shows the best solutions especially when the grid size is small enough.

• Interaction and multiscale mechanics
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• 제1권1호
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• pp.53-81
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• 2008

The theory of microlocal analysis of hyperbolic partial differential equations shows that the energy density associated to their high-frequency solutions satisfies transport equations, or radiative transfer equations for randomly heterogeneous materials with correlation lengths comparable to the (small) wavelength. The main limitation to the existing developments is the consideration of boundary or interface conditions for the energy and power flow densities. This paper deals with the high-frequency transport regime in coupled heterogeneous structures. An analytical model for the derivation of high-frequency power flow reflection/transmission coefficients at a beam or a plate junction is proposed. These results may be used in subsequent computations to solve numerically the transport equations for coupled systems, including interface conditions. Applications of this research concern the prediction of the transient response of slender structures impacted by acoustic or mechanical shocks.

• 전자공학회논문지D
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• 제34D권3호
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• pp.17-24
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• 1997

Broad-band RAM's (Radar absorbing materials) are designed by multi-layered lossy dielectrics. The depth, the relative permittivity and the loss tangent of each layer are optimized in order to meet the required reflective power over the specified frequency range using a genetic algorithm. The reflection coefficients are calculated by the continued fraction method. A new population model of the partial initialization method during iterations is applied for the multi-modal functions to enhance the performance of the genetic algorithm. The optimal RAN's are designed by setting the relative permittivity and the loss tangent of the dielectrics as a funtion of the frequency over 5~20GHz.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2057-2059
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• 1999

This paper describes the phenomena of the refraction and reflection when the ultrasonic signals generated by PD(Partial Discharge) in a transformer propagate through the boundary between insulating oil and the tank of the transformer. In this paper, considering the characteristic of the ultrasonic signal and the velocity of the propagation in medium, propagation time from PD source to sensor for incidence angle was calculated. As a result, it was found that the shortest time at specific angle exists. Taking into account the velocity of the propagation in medium, the shortest time with a computer was simulated. It was shown that the simulation was same as experimental result at a real PD source in the transformer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1323-1328
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• 2001

The theory of NAH is based on the assumption of reflection free. However, it is not always possible to meet this condition in many practical cases. Thus, a decomposition of direct and reflected fields is needed to apply NAH to reflective condition for noise problems. In addition, the decomposition of direct and reflected field can give acoustic characteristics of reflecting surfaces. This paper presents that in this condition the decomposition can also be successfully done by MUSIC(Multiple Signal Classification) power method and beamforming method, and that numerical simulation and real experiments verify its performance.

• Current Optics and Photonics
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• 제2권6호
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• pp.563-567
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• 2018

We propose and experimentally demonstrate a simple tunable photonic microwave band-pass filter with high resolution using a reflective semiconductor optical amplifier (RSOA) and an optical time-delay line. The RSOA is used as a gain medium for generating cross-gain modulation (XGM) effect as well as an optical source. The optical source provides narrow spectral width by self-injection locking the RSOA in conjunction with a partial reflection filter with specific center wavelength. Then, when the RSOA is operated in the saturation region and the modulated recursive signal is injected into the RSOA, the recursive signal is inversely copied to the injection locked optical source due to the XGM effect. Also, the tunability of the passband of the proposed microwave filter is shown by controlling an optical time-delay line in a recursive loop.

• 대한수학회지
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• 제56권2호
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• pp.353-385
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• 2019

In this paper, we introduce the notion of combinatorial Auslander-Reiten (AR) quivers for commutation classes [${\tilde{w}}]$ of w in a finite Weyl group. This combinatorial object is the Hasse diagram of the convex partial order ${\prec}_{[{\tilde{w}}]}$ on the subset ${\Phi}(w)$ of positive roots. By analyzing properties of the combinatorial AR-quivers with labelings and reflection functors, we can apply their properties to the representation theory of KLR algebras and dual PBW-basis associated to any commutation class [${\tilde{w}}_0$] of the longest element $w_0$ of any finite type.

• 한국해안·해양공학회논문집
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• 제21권5호
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• pp.410-418
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• 2009

선형포텐셜이론을 가정하여 부분 반사 안벽 앞에 계류된 부유체의 동유체력과 운동응답을 해석할 수 있는 경계요소법을 개발 적용하였다. 동유체력인 부가질량과 감쇠계수는 부유체의 잠긴깊이와 안벽에서의 반사율 그리고 부유체와 안벽사이의 떨어진 거리에 밀접한 관련이 있다. 특히 안벽에서의 반사율은 안벽과 부유체사이의 제한유체영역내에서 발생하는 공진현상에 의하여 증폭된 운동변위의 피크값을 줄이는 등 운동응답에 중요한 영향을 미친다. 개발된 수치해석법은 부유체의 형상, 입사각, 안벽의 속성, 입사파의 특성 등의 변화에 따른 부유체의 운동성능을 평가하는데 이용될 것이며, 또한 항만내 계류된 선박의 운동특성을 고려한 항만설계의 기초자료로 활용 될 것이다.

• 한국광학회지
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• 제20권5호
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• pp.276-280
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• 2009

Cr:YAG 결정을 포화흡수체로 사용하여 수동형 Q-스위치시킨 다이오드 레이저 여기 Nd:$YVO_4$ 레이저를 제작하였다. Cr:YAG 결정의 한 면에 여기 빛 파장(808 nm)에 대해 고반사 코팅을 한 후, Nd:$YVO_4$ 결정과 접촉시켜 공진기를 구성하였다. Cr:YAG의 한 면에 여기 다이오드 레이저를 반사시키는 코팅을 입혀 공진기의 광변환 효율을 높임과 동시에, 여기빔에 의한 포화흡수체의 표백현상을 방지하여 안정된 출력이 나오게 하였다. 레이저 이득 매질 및 포화흡수체의 온도는 열전 냉각기와 냉각수를 사용하여 안정화 시켰다. 온도안정화를 시킨 상태에서 발진되는 펄스의 첨두 출력 요동(peak to peak)은 4%였다. 다이오드 레이저의 출력이 1 W일 때, 출력 펄스의 반복률은 평균 9 KHz 였으며, 최소 펄스폭은 7.11 ns, 최고 출력은 16.27 mW였다.