• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.282-282
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• 1996

The purpose of this study was to prepare the nifedipine dry elixir (NDE) and coated nifedipine dry elixir (CNDE) containing nifedipine ethanol solution for improving the dissolution rate and bioavailability of nifedipine. NDE containing nifedipine and ethanol in wall materials of dextrin was prepared using a spray-dryer and then NDE was coated with eudragit acrylic resin to make CNDE. Shape and size of the NDE and CNDE were monitored by scanning electron micrograph and laser particle size analyzer In vitro dissolution tests were performed in simulated gastric and intestinal fluid. Bioavailability of NDE and CNDE were compared with drug powder suspension and commercial soft capsule after oral administration of the preparations to rats. NDE and CNDE are spherical in shape. Cross-sectional view of dry elixirs indicates the large inter cavity containing ethanolic drug solution in shell. Geometric mean diameter of NDE and CNDE is about 6.64 and 8.70 $\mu\textrm{m}$, respectively. Drug dissolution rate within first 5 min from NDE increased dramatically irrespective of dissolution medium. However, CNDE showed a particularly retarded dissolution rate in pH 1.2 simulated gastric fluid compared with NDE. The bioavailability of nifedipine in the NDE was increased dramatically compared with drug powder suspension. CNDE reduced initial burst-out plasma peak compared with NDE. CNDE as a sustained release delivery system could reduce the initial burst-out plasma peak due to controlling the release rate of nifedipine from NDE and maintain the effective plasma level over a longer period within therapeutic window with enhanced bioavailability of nifedipine.

• 한국구조물진단유지관리공학회 논문집
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• 제13권5호통권57호
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• pp.101-108
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• 2009

비파괴 시험을 이용한 RC 구조물의 진단에 있어서 비파괴 측정값의 적절한 해석을 통해서만 현 구조물의 상태진단이 가능하다. 보다 정확한 구조물의 상태진단은 비파괴 시험의 정밀성, 변이성 등과 같은 여러 가지 요소에 의하여 좌우된다. 특히 비파괴 시험을 이용한 측정값과 구조물의 상태에 있어서의 불확실성은 정밀한 상태진단에 큰 영향을 미친다. 본 논문은 현재 사용이 증가되고 있는 비파괴 장비의 올바른 선택과 정확한 구조물의 진단을 위하여, 비파괴 측정값의 확률적 해석법의 기초를 제공하고 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.803-808
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• 2001

Mathematical basis of interpretation of data from nondestructive evaluation (NDE) methods in bridge inspection is presented. In bridge inspection with NDE methods, NDE data are not assessments. NDE data must be interpreted as condition of element. Interpretation is then assessment. Correct assessments of conditions of bridge elements depend on the accuracy and variability in test data as well as on the uncertainty of correlations between attributes (what is measured) and conditions (what is sought in the inspection). Inaccuracy and variability in test data defines the qualify or NDE test. The qualify or test itself is important, but in view of condition assessment, the significance of uncertainty in correlations of attributes and conditions must be combined. NDE methods that are accurate in their measurements may still be found to be poor methods if attributes are uncertain indicators of condition of bridge elements. This paper reports mathematical presentation of inaccuracy and variability in test data and of uncertainty in correlation of attributes to element conditions with three examples of NDE methods.

• 한국구조물진단유지관리공학회 논문집
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• 제11권3호
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• pp.167-175
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• 2007

정밀한 구조물의 상태진단 혹은 안전성 평가는 비파괴 시험의 정밀성(Accuracy), 변이성(Variability) 등과 같은 여러 가지 요소에 의하여 좌우된다. 특히 비파괴 시험을 이용한 측정값과 구조물의 상태에 있어서의 불확실성(Uncertainty)은 정밀한 상태진단에 큰 영향을 미친다. 비파괴 시험을 활용함에 있어서의(간접조사) 신뢰할만한 비파괴 장비라면 현 구조물의 상태(피해면적)를 정확하게 나타낼 수 있어야 한다. 본 논문은 현재 사용이 증가되고 있는 비파괴 장비의 올바른 선택과 정확한 구조물의 안전 진단을 위하여, 비파괴장비의 성능 평가에 있어 확률적 기초를 제공한다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2005년도 동계학술연구발표회 및 2차 아시안포럼
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• pp.6-6
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• 2005

• 동위원소회보
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• 제2권1호
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• pp.4-7
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• 1987

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.961-962
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• 2005

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.190-194
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• 2003

Two different types of nondestructive evaluation (NDE) techniques were employed to investigate the tensile behavior of ceramic matrix composites (CMCs). Two NDE methods, ultrasonic testing (UT) and infrared (IR) thermography, were used to assess defects and/or damage evolution before and during mechanical testing. Prior to tensile testing, a UTC-scan and a xenon flash method were performed to obtain initial defect information in light of UT C-scans and thermal diffusivity maps, respectively. An IR camera was used for in-situ monitoring of progressive damages. The IR camera measured temperature changes during tensile testing. This paper has presented the feasibility of using NDE techniques to interpret structural performance of CMCs.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.504-512
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• 2003

Simulation programs have been developed and used as an attempt to improve the accuracy of Non-Destructive Evaluation(NDE) techniques. The applicability of these programs is very limited, however, because it is difficult to describe the delicacy of the propagation of stress waves. To investigate the applicability of the finite element analysis for stress wave-based NDE techniques numerical simulation for Impact-Echo method and SASW method is performed. The numerical studies are performed to determine the essential parameters such as contact time of impact load, mesh size and time step size. These studies show that the choice of parameter is very important for improving the accuracy and confidence of the numerical procedure and, thereby, the applicability of the numerical analysis for stress wave-based NDE techniques

• 공학기술논문지
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• 제11권4호
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• pp.245-251
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• 2018

Terahertz waves (T-ray) was extensively studied for the NDE (nondestructive evaluation) of characterization of trailing edges for a use of turbines composed with composite materials. The used NDE system were consisted of both CW(Continuous wave) and TDS (Time domain spectroscopy). The FRP composites were utilized for two kinds of both trailing edges of wind energy (non-conducting polymeric composites) and carbon fiber composites with conducting properties. The signals of T-ray in the TDS (Time domain spectroscopy) mode resembles almost that of ultrasound waves; however, a terahertz pulse could not penetrate a material with conductivity unlike ultrasound. Also, a method was suggested to obtain the "n" in the materials, which is called the refractive index (n). The data of refractive index (n) could be solved for the trailing edges. The trailing edges were scanned for characterization and inspection. C-scan and B-scan images were obtained and best optimal NDE techniques were suggested for complicated geometry samples by terahertz radiation. Especially, it is found that the defect image of T-ray corresponded with defect locations for the trailing edges of wind mill.