• 대한의용생체공학회:의공학회지
• /
• 제17권3호
• /
• pp.365-372
• /
• 1996

The researches to acquire diagnostic parameters from ultrasonic images are advanced with the progress of the digital image processing technique. Especially, the detection of endocardial boundary is very important in ultrasonic images, because endocardial boundary is used as a clinical parameter to estimate both the cardiac area and the variation of cardiac volume. Various methods to detect cardiac boundary are proposed, but these are insufficient to detect boundary. In this paper, an algorithm that detects the endocardial boundary, expanding the cavity region from the center using statistical information, is proposed The value of mean and sty:nd, wd deviation in cavity region is lower than those in muscle re- gion. Therefore, if we define the multiplication of mean and standard deviation as homogeneous coefficient, it can lead to conclusion that the pixels with small variation of these coefficleno are cavity region, and extraction of endocardial boundary from cavity region is possible. The proposed method detected endocardial boundary more effectively than edge based or threshold based method and is robuster to noise than radial searching method that has high dependency for center position.

• Journal of Acupuncture Research
• /
• 제33권3호
• /
• pp.17-28
• /
• 2016

Objectives : This study was designed to investigate the analgesic effects of Taxus cuspidata pharmacopuncture(TCP) at KI03 on formalin-induced pain in rats and to evaluate the efficiency of different extraction methods of Taxus cuspidata(TC). Methods : 30 rats were divided into 5 groups, each consisting of 6 rats. Each of the groups was treated two times. The first treatment for its right KI03 was as follows: rats were treated with normal saline(NOR), normal saline(CON), hot-water extraction of TC(W), ethanol extraction of TC(E), and ultrasonification extraction of TC(U). The second treatment was given 35 mins after the first one. Rats in NOR were treated with normal saline at their hind-paw. All groups, except NOR, were treated with formalin(5 %, $40{\mu}{\ell}$) at their hind-paw. To evaluate pain behavior, Ultrasonic vocalization(USV) was examined to be around 18~30 kHz. After analysis of USV, blood samples were taken from the rats for analysis of Substance P, aspartate aminotransferase(AST) and alanine aminotransferase(ALT). Results : In the experimental groups, USV was significantly decreased compared with CON and similar to that of NOR in the early phase. But there were no significant differences among the three extraction methods of TC. In addition, Substance P of W was significantly decreased. AST and ALT activation showed no significant differences among the 5 groups. Conclusion : These results show that regardless of extraction methods of TC, TCP at KI03 has analgesic effects in the early phase on formalin-induced pain in rats. In particular, hot-water extraction of TC significantly reduces Substance P activation.

• 제어로봇시스템학회논문지
• /
• 제10권9호
• /
• pp.779-784
• /
• 2004

This paper describes a sonic polygonal multiple reflection range sensor (SPMRS), which uses multiple reflection properties usually ignored in ultrasonic sensors as disturbances or noises. Targets such as a plane, corner, edge, or cylinder in indoor environments can easily be detected by the multiple reflection patterns obtained with a SPMRS system. Target classification and feature data extraction, such as distance and azimuth to the target, are computed simultaneously by considering the geometrical relationships between the detected targets, and finally the environment model is generated by refining the detected targets. In addition, the narrow field of view of a sonar range sensor is increased and the scanning time is reduced by active motion of the SPMRS stepping servomechanism.

• 한국정밀공학회지
• /
• 제16권8호
• /
• pp.170-177
• /
• 1999

과공정 알루미늄 실리콘 합금 (Hypereutectic Al-Si Alloy, A390)은 내마멸성 및 우수한 강성에 의해서 자동차 부품에 많이 사용되고 있다. 본 연구에서는 초음파 진동 절삭에 의한 과공정 알루미늄 실리콘 합금의 가공성과 실리콘 석출의 실험적 연구를 수행 하였다. 최적 공구와 가공조건의 선정 실험을 통하여 보다 효과적인 초음파 진동 절삭을 수행하였으며, 과공정 알루미늄 실리콘 합금의 가공 표면거칠기와 실리콘 석출은 절삭속도와 절삭깊이와 밀접한 연관성을 갖고 있다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.550-554
• /
• 2014

Regarding thin films in MEMS/NEMS structures, the exact evaluation of mechanical properties is very essential to enhance the reliability of their design and manufacturing. However, such methods as a tensile test and a resonance test, general methods to measure elastic moduli, cannot be applied to thin films since its thickness is so small. This work concerns guided wave based elastic modulus measurement method. To this end, guided wave excitation and detection system using a pulsed laser and a laser interferometry has been established. Also an elastic modulus extraction algorithm from the measured guided wave signal was developed. Finally, it was applied to actual thin film structures such as Ni-Si and Al-Si multilayers. From experimental results, we confirm that the proposed method has considerable feasibility to measure elastic properties of thin films.

• 한국유체기계학회 논문집
• /
• 제12권4호
• /
• pp.54-62
• /
• 2009

The feedwater heaters are Critical components in a nuclear power plant. As the operation years of heaters go by, the maintenance costs required for continuous operation increase. When the carbon steel components in nuclear make contact with running fluid, the wall thinning caused by FAC (flow accelerated corrosion) can be generated. Local wall thinning is inevitable at the area around wet steam entrance to be attacked due to the long term operation. Sometimes the shell with thinned wall is eventually ruptured. To identify the relationship between the local wall thinning and fluid behavior of the feedwater heater, the practical data of a plant, which were based on ultrasonic thickness measurement tests, were analyzed and CFD(Computed Fluid Dynamics) analyses were performed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
• /
• pp.830-835
• /
• 2003

This paper describes a sonic polygonal multiple reflection range sensor (SPMRS), which uses multiple reflection properties usually ignored in ultrasonic sensors as disturbances or noises. Targets such as a plane, corner, edge, or cylinder in indoor environments can easily be detected by the multiple reflection patterns obtained with a SPMRS system. Target classification and feature data extraction, such as distance and azimuth to the target, are computed simultaneously by considering the geometrical relationships between the detected targets, and finally the environment model is generated by refining the detected targets. In addition, the narrow field of view of a sonar range sensor is increased and the scanning time is reduced by active motion of the SPMRS stepping servomechanism.

• 대한기계학회논문집A
• /
• 제20권4호
• /
• pp.1309-1319
• /
• 1996

The research for the classification of the natural defects in welding zone is performd using the neuro-pattern recognition technology. The signal pattern recognition package including the user's defined function is developed to perform the digital signal processing, feature extraction, feature selection and classifier selection, The neural network classifier and the statistical classifiers such as the linear discriminant function classifier and the empirical Bayesian calssifier are compared and discussed. The neuro-pattern recognition technique is applied to the classificaiton of such natural defects as root crack, incomplete penetration, lack of fusion, slag inclusion, porosity, etc. If appropriately learned, the neural network classifier is concluded to be better than the statistical classifiers in the classification of the natural welding defects.

• 한국산학기술학회논문지
• /
• 제13권10호
• /
• pp.4927-4935
• /
• 2012

강황은 다양한 약리활성을 가진 약초이다. 강황에 포함된 curcumin, demethoxycurcumin(DMC)과 bisdemethoxycurcumin(BDMC)을 침적과 초음파방법을 이용하여 추출하였다. 그리고 고체상추출(SPE)을 사용하여 추출효율을 확인 하였다. 추출액은 3가지 상업용 $C_{18}$ 역상 고성능 액체 크로마토그래피에 의해 이동상으로 물과 아세토나이트릴을 사용하여 일정용매법으로 동시분리 분석을 하였다. 유속은 1.0mL/min, 주입부피는 $10{\mu}L$, 컬럼오븐 온도 $40^{\circ}C$, 파장 425nm에서 수행되었다. 실험결과, RS tech column을 사용하고 물과 아세토나이트릴의 조성비가 (50 : 50vol%)일 때 최적 조건을 얻을 수 있었다. 용매조성(물과 메탄올)에 따른 추출 수율에의 영향을 살펴본 결과 100% 메탄올에서 curcuminoids(추출시간 4h)가 가장 많이 추출되었고, 수용성 메탄올 조성보다 함량이 높았다. 100% 물에 의해, 고체상추출은 curcuminoids의 추출함량(mAU${\times}$mim)이 침적과 초음파방법보다 24.5와 14.3배 높았다. 이상의 결과는 제약 및 기능성 소재로서의 응용 가능성을 나타내었다.

• 생명과학회지
• /
• 제21권1호
• /
• pp.56-61
• /
• 2011

본 연구는 청나래고사리 성엽 추출물의 항산화물질의 함량과 항산화능을 향상시킬 수 있는 효과적인 추출방법을 개발하기 위하여 시행하였다. 동결건조한 청나래고사리 성엽의 분쇄시료 1 g을 메탄올, 80% 에탄올 및 물 등 3가지 용매와 섞은 후 6시간 동안 상온 침지, $60^{\circ}C$ 가열 및 200 rpm에서 교반하여 추출하거나 42 kHz의 초음파 수조에서 15, 30, 45분 동안 추출하였다. 추출물은 여과한 다음 가용성고형분, 총 폴리페놀 및 총 플라보노이드의 함량을 측정하였으며, 항산화활성은 DPPH와 ABTS radical 소거활성을 $RC_{50}$으로 환산하여 측정하였다. 80% 에탄올을 용매로 하여 30분 동안 초음파추출 하였을 때 가용성고형분(0.317 $g{\cdot}g^{-1}$ db), 총 폴리페놀(70.90 $mg{\cdot}g^{-1}$ db) 및 총 플라보노이드(41.53 $mg{\cdot}g^{-1}$ db)의 추출수율이 가장 우수하였으며, DPPH와 ABTS radical 소거활성 또한 가장 우수하였다(각 $RC_{50}$=0.14 $mg{\cdot}ml^{-1}$와 0.09 $mg{\cdot}ml^{-1}$). 상기의 연구결과에 따라 청나래고사리의 성엽은 천연항산화소재로 활용가능하며, 80% 에탄올을 용매로 15-30분 동안 초음파추출하는 것이 추출물의 항산화효과를 증가시키며 추출에 소요되는 시간을 줄일 수 있는 효과적인 추출방법으로 생각되었다.