• 분석과학
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• 제35권2호
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• pp.60-68
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• 2022

In this study, we developed and validated a sensitive analytical method to quantify baphicacanthin A in mouse plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The standard calibration curves for baphicacanthin A ranged from 0.5 to 200 ng/mL and were linear, with an r² of 0.985. The inter- and intra-day accuracy and precision and the stability fell within the acceptance criteria. Besides, we investigated the pharmacokinetics of baphicacanthin A following its intravenous (5 mg/kg) and oral administration (30 mg/kg). Intravenously injected baphicacanthin A showed biphasic elimination kinetics with high clearance and volume of distribution values. Furthermore, baphicacanthin A showed a rapid absorption but low aqueous solubility (182.51±0.20 mg/mL), resulting in low plasma concentrations and low oral bioavailability (2.49 %). Thus, we successfully documented the pharmacokinetic properties of baphicacanthin A using this newly developed sensitive LC-MS/MS quantification method, which could be used in future lead optimization and biopharmaceutic studies.

• 분석과학
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• 제31권3호
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• pp.107-111
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• 2018

Currently, ultraviolet-visible spectrophotometry and titration methods are used for assay tests of tramadol hydrochloride injection and raw material in the Korean Pharmacopoeia XI (KP XI). Titration has also been used in the British Pharmacopoeia (BP 2013) for the assay test of tramadol hydrochloride, and the HPLC assay for tramadol hydrochloride raw material has been used in the United States Pharmacopeia (USP 39). In this study, we developed an alternative HPLC assay method for tramadol hydrochloride injection that is up to date and specific, and employs the same method as tramadol hydrochloride capsules. Validation of the HPLC method was conducted to determine linearity, precision, accuracy, system suitability, and robustness. The linearity of the calibration curves in the desired concentration range was good ($r^2$ > 0.9999). RSDs of intra-day precision obtained were 0.05-0.08 % and inter-day precision obtained were 0.08-0.19 %. Accuracy was obtained with recoveries in the range of 98.16 % and 100.90 %. As a result of the system's suitability, the RSD of both retention time and the peak area obtained were 0.07 %. The values of the plate number and tailing factor of tramadol hydrochloride obtained were 7076 and 1.16, respectively. Because of the intermediate precision and robustness of the developed assay, it is expected to become a valuable tool for revising the Korean Pharmacopoeia (KP XI).

• 분석과학
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• 제23권6호
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• pp.587-594
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• 2010

완제품의 주성분인 옥시라세탐이 함유된 의약품의 시험법실시 계획서에 따른 시험이 적절히 진행되었는지 시험법의 검증여부를 하고 본 protocol이 완제품 중 옥시라세탐의 정량분석을 위한 HPLC 분석법의 타당성을 검증하기 위한 문서화된 절차를 제공하는 것을 목적으로 한다. 본 실험에서는 옥시라세탐 함량시험에 사용된 분석법에 대하여 시스템 적합성, 정밀성, 직선성, 범위, 정확도, 특이성, 정량한계, 검출한계에 대하여 확인하였다. 실험결과 시스템적합성에서 정밀도(RSD%) 0.127%이하, 이론단수 15081, tailing factor 0.49, 그리고 분리능 32.41을 나타내었고, 정밀도실험에서는 RSD% 0.359% 이하의 결과를 보였다. 그리고 직선성 실험에서는 상관계수($R^2$)가 1을 나타내었고, 정확도 실험에서는 recovery test로서 최소 98.4%, 최대 99.6%로 기준을 만족하였다. 검출한계는 0.1 mg/L이였으며, 정량한계는 0.5 mg/L이었다. 그리고 특이성 실험에 있어서도 기준을 만족하는 결과를 나타내어 옥시라세탐을 주성분으로 하는 완제의약품 시험법은 적합한 시험법임이 검증되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1081-1082
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• 2011

In order to predict the accuracy of the linear motion machine tools, the force characteristics such as the detent force, the attraction force and the moment are estimated by analytical method or FEM. In this paper, we proposed the analytical calculation process for the force characteristics of a linear motor. The analytical results are good agreement with FEM one. They could be used for the precision prediction simulator with the information of linear bearings, encoders, etc.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.123-124
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• 2023

This study successfully developed a chromium-free paper-based analytical device (µPAD) for chloride detection in fresh concrete. The sensing materials were chemically synthesized and coated to the paper through drop casting. The fabricated µPAD was thoroughly tested with various concentrations of chloride ions. Upon interaction with the µPAD, the chloride ions in the solution react with a chromium-free silver compound, exhibiting a specific coloring height proportional to the absolute chloride concentration. The height of the color change during a reaction can vary based on the chloride concentration, which allows for predicting the chloride concentration in a solution. The results reveal that µPAD has extraordinary precision in identifying chloride in fresh concrete, which highlights its immense potential for future applications.

• 약학회지
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• 제58권3호
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• pp.190-199
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• 2014

The Korean Pharmaceutical Codex (KPC) analytical method of ambroxol hydrochloride and clenbuterol hydrochloride formulation is complicated and needed to carry out multiple processes during the test. To improve the low efficiency of analytical procedure that makes pharmaceutical laboratory consume much time and high cost to conduct the test of this formulation, this study was performed for simplifying the pretreatment process and optimizing conditions of the HPLC assay. The analytical procedure using HPLC was developed to establish analytical specification for ambroxol hydrochloride and clenbuterol hydrochloride formulations. The newly developed analytical method has good linearity ($R^2$ >0.999), specificity, precision (RSD<1.0%) and the recovery ranges of 98.50~101.84% for ambroxol, 98.29~101.35% for clenbuterol syrup and 98.66~101.71% for clenbuterol tablets. The LOQs were 0.204 ${\mu}g/ml$ for ambroxol, 0.021 ${\mu}g/ml$ for clenbuterol syrup and 0.073 ${\mu}g/ml$ for clenbuterol tablets. The new method was performed with commercially available samples to confirm analytical conditions and validated to be suitable for saving time and cost to control the quality of routine manufactured products. This analytical method will be used for revising the monograph of ambroxol hydrochloride and clenbuterol hydrochloride formulation in next supplement of KPC.

• International Journal of Precision Engineering and Manufacturing
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• 제2권3호
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• pp.47-53
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• 2001

This paper investigates the characteristics of interlaminar fracture toughness of foam core sandwich structures under opening mode by using the double cantilever beam (DCB) specimens which are Carbon/Epoxy and foam core composites. Instead of using a DCB specimen of symmetric geometry, a non-symmetric DCB specimen was used to calculate the interlaminar fracture toughness. Three approaches for calculating the energy release rate(G$\sub$IC/) were used and fracture toughness of foam core sandwich structures made by autoclave, vacuum bagging and hotpress were compared. Experiment, analysis using nonlinear beam bending theory, and numerical work by FEM methods were performed. Bonding surface compensation and equivalent moment of inertia were used to calculate the energy release rate in nonlinear analytical work. Conclusions of experimental, nonlinear analytical and FEM methods were compared. It is, also, shown that the vacuum bagging forming can substitute the method of autoclave without serious loss of Mode I energy release rate(G$\sub$I/).

• 대한수의학회지
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• 제48권1호
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• pp.33-38
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• 2008

In veterinary medicine amitraz has been used as an insecticide to eliminates mites, lice, and ticks in dogs, cats, goats, swine and cattle. The objective of present study was to developed an analytical method using one-step extraction and determination of the amitraz in veterinary drugs by liquid chromatography (LC). The amitraz was analyzed by LC equipped with Waters XTerra RP18 ($4.8{\times}250mm;\;5{\mu}m;\;Waters,\;USA$) analytical column, using 75% acetonitrile (acetonitrile/D.W; 75/25) at 1.0 ml/ min. The UV-VIS detection of amitraz was made at 290 nm. Calibration graphs were linear with very good correlation coefficients ($r^2>0.9999$) from $80{\sim}120{\mu}g/ml$. The limit of detection was $0.09{\mu}g/ml $ and limit of quantification was $0.27{\mu}g/ml $. The method showed good intra-day precision (CV 0.05~0.09%) and inter-day precision (CV 0.06~0.18%).

• 한국정밀공학회지
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• 제23권6호
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• pp.119-127
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• 2006

A non-destructive time domain approach to examine structural damage using parameterized partial differential equations and Galerkin approximation techniques is presented. The time domain analysis for damage detection is independent of modal parameters and analytical models unlike frequency domain methods which generally rely on analytical models. The time history of the vibration response of the structure was used to identify the presence of damage. Damage in a structure causes changes in the physical coefficients of mass density, elastic modulus and damping coefficients. This is a part of our ongoing effort on the general problem of modeling and parameter estimation for internal damping mechanisms in a composite beam. Namely, in detecting damage through time-domain or frequency-domain data from smart sensors, the common damages are changed in modal properties such as natural frequencies, mode shapes, and mode shape curvature. This paper examines the use of beam-like structures with piezoceramic sensors and actuators to perform identification of those physical parameters, and detect the damage. Experimental results are presented from tests on cantilevered composite beams damaged at different locations and different dimensions. It is demonstrated that the method can sense the presence of damage and obtain the position of a damage.

• 한국정밀공학회지
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• 제22권1호
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• pp.115-121
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• 2005

Micromachines are extremely novel artifacts with a variety of special characteristics. Utilizing their tiny dimensions ranging roughly from 10 to $10^3$ micro-meters, the micromachines can perform tasks in a revolutionary manner that would be impossible for conventional artifacts. Micromachines are in general related to various coupled physical phenomena. They are required to be evaluated and designed considering the coupled phenomena. This paper describes finite element analysis (FEA) simulation of practical behaviors for the micro actuator. Especially, electric field modeling in micro actuators has been generally restricted to in-plane two-dimensional finite element analysis because of the complexity of the micro actuator geometry. However, in this paper, the actual three-dimensional geometry of the micro actuator is considered. The starting torque obtained from the in-plane two-dimensional analytical solutions were compared with that of the actual three-dimensional FE analysis results. The starting torque is proportional to $V^2$, and that the two-dimensional analytical solutions are larger than the three- dimensional FE ones. It is found that the evaluation of micro actuator has to be considered electrical leakage phenomenon.