• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.563-567
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• 2006

The application of a synergistic solvent extraction by the formation of ternary complex with pyrocatechol violet (PV) and benzalkonium chloride (BC) was studied for determination of trace Zn(II) in water samples. The pH of sample solution and the amount of PV and BC added were optimized for the formation of the stable complex, a proper solvent was selected for the effective extraction, and the concentration of nitric acid was fixed for the back extraction of the complex from the solvent. After the ionic strength of 100 mL sample solution was adjusted to 0.1 M by adding NaCl and the pH was fixed at 9 with a carbonate buffer, 1.0 mL of 2% PV solution was added to form Zn(II)-PV complex then the Zn(II)-PV/BC ternary complex was made by adding 1.0 mL of 10% BC solution. The ternary complex was extracted into 10 mL of MIBK. And the ternary complex was back-extracted with 10 mL of 1.0 mol/L nitric acid to determine Zn(II) by a flame atomic absorption spectrophotometer (flame-AAS). The interference of concomitant ions on the extraction of Zn(II) was investigated. This procedure was applied to the analysis of three real samples such as Dalbang-dam water, laboratory tap water and Jungnajin seawater. The recoveries of Zn(II) in spiked samples were 86.58-104.1%.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.106-111
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• 2021

In this study, an ultrasound-assisted micellar extraction process was developed to efficiently purify the anticancer substance paclitaxel from the plant cell Taxus chinensis. The problem of many extraction steps and long phase separation time in the traditional micellar process could be dramatically improved. The highest paclitaxel yield (~96%, extracted twice) was obtained at 180 W of ultrasonic power and 1.5 h of ultrasonic irradiation time, which was 24.7% higher than that of the traditional method. In addition, the partition coefficient (K) showed a maximum value (24.0) at 180 W of ultrasonic power and 1.5 h of irradiation time. There was no significant difference in the purity of paclitaxel, and the purity of initial paclitaxel (6.81%) increased to 22.0% after purification. Compared to the traditional method, the phase separation time of the back extraction decreased by 40.7-56.2% (ultrasonic power 80 W), 46.3-67.6% (ultrasonic power 180 W), and 51.9-67.6% (ultrasonic power 250 W), respectively. The phase separation time decreased as the ultrasonic power (80-250 W) and irradiation time (0.5-2.5 h) increased.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.553-556
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• 1998

The 1-D numerical model and its extraction methodology are suggested and these simulation results for the S-swing as a function of back-gate voltage are well matched with the measured. S-swing characteristics are analyzed using PD-SOI devices with enough deeper regions up to substrates. The PD-SOI device doesn't have to be short channel to see the anomalous subthreshold phenomena based on the back gate bias. This results recommend to operate better SOI device performances by controlling the back gate voltages. So SOI performances will be much optimistic with proper control of the back-gate voltage for the already- proven- high- performance (APHP) SOI VLSIs.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.101-105
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• 2002

Counters for various kinds of bank notes require high-speed distinctive point extraction and recognition for notes. In this paper we propose a new point extraction and data extraction method from specific parts of a bank note representing the same color. The recognition algorithm uses a back-propagation neural network that has coordinate data input. The proposed algorithm is designed to minimize recognition time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.519-523
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• 2007

In this paper, we propose a precise parameter extraction of interior permanent magnet (IPM) motors based on finite element analysis. For the calculation of the two-axis inductances Ld and Lq, the slotting effect and cross magnetization due to torque angle are considered. It is examined that back electro-motive force (BEMF) constant is affected by the magnetic saturation in different ways dependent on motor types. Numerical analyses and some measurements are performed for a spoke type and a flux barrier type IPM motors

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.349-351
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• 2005

현재 다양한 인터넷 콘텐츠들에 의해 많은 정보가 공유되고 있으며, 유익한 정보들과 더불어 성인물과 같은 유해한 정보들이 있다. 이로 인하여 여러 문제점들이 야기되고 있으며, 이를 해결하기 위해 다양한 방법들이 제안되고 있다. 그 중에서 성인 영상 차단을 위한 연구도 많이 행해지고 있으며 주로 색상을 이용한 방법을 사용하고 있다. 그러나 살색과 유사한 영상이나 노출이 심한 영상에는 성인 영상 검출의 신뢰성이 떨어지는 단점을 갖는다. 본 논문에서는 이런 문제점을 해결하기 위해 새로운 성인 영상 차단 방법을 제안한다. 기존의 제안된 살색 검출을 이용한 방법을 기반으로 성인 영상물로 판정될 수 있는 신체 부위를 검출함으로써 강인한 성인 영상 차단을 한다. 신체 부위에 대한 판별을 위해 여러 기저 영상에서 특징 벡터를 추출하고. 이 벡터를 Back Propagation(BP) 신경망의 데이터로 이용하여 학습한다. 제안한 성인 영상 차단 방법의 성능을 여러 장의 살색과 유사한 색상의 물체 영상과 노출이 심한 영상, 성인 영상을 이용한 종합적인 실험 결과인 성인 영상 검출률을 통해 증명한다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.7
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• pp.119-128
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• 1994

In this paper, we propose a method for facial feature extraction and recognition algorithm using neural networks. First we extract a face part from the background image based on the knowledge that it is located in the center of an input image and that the background is homogeneous. Then using vertical and horizontal projections. We extract features from the separated face image using knowledge base of human faces. In the recognition step we use the back propagation algorithm of the neural networks and in the learning step to reduce the computation time we vary learning and momentum rates. Our technique recognizes 6 women and 14 men correctly.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.471-476
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• 2010

In this paper, we propose an effective method that recognizes the vehicle license plate using RGB color information and back-propagation neural network algorithm. First, the image of the vehicle license plate is adjusted by the Mean of Blue values in the vehicle plate and two candidate areas of Red and Green region are classified by calculating the differences of pixel values and the final Green area is searched by back-propagation algorithm. Second, our method detects the area of the vehicle plate using the frequence of the horizontal and the vertical histogram. Finally, each of codes are detected by an edge detection algorithm and are recognized by error back-propagation algorithm. In order to evaluate the performance of our proposed extraction and recognition method, we have run experiments on a new car plates. Experimental results showed that the proposed license plate extraction is better than that of existing HSI information model and the overall recognition was effective.

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.05a
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• pp.62-63
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• 2001

• Journal of the Korean Chemical Society
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• v.41 no.9
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• pp.471-482
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• 1997

GC/MS was used to find an optimum experimental condition for the screening of organic acids in urine. Urinary organic acids were isolated through the liquid-liquid extraction method (LLE) to examine the influence of pH and the effect of including the back extraction and oximation processes respectively on the extraction. When pH was adjusted to 0.5 during the extraction without oximation process, relatively higher recovery rate and the smallest relative standard deviations (0.3-12.4%) were obtained. By removing the interference, the addition of back extraction made possible surer identification of organic acids with retention time of 15-16 minutes. Under this condition, we obtained the content distribution of urinary organic acids in healthy Korean children (n=16) by establishing the calibration curves for 51 standard organic acids.