• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2088-2092
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• 2011

The accelerated thermal aging of CSPE(chloro sulfonate polyethylene) of test cables were carried out for the period equal to 10, 20 and 30 years in air at $100^{\circ}C$, respectively. The CSPE cables(TAIHAN electric wire Co. Ltd) which installed in nuclear power plant for three years were used as starting materials. Condition monitering methods of the accelerated thermal aging of CSPE cables were estimated through indenter modulus and OIT(oxidation induction time) of IEC 62582, and those were newly estimated through volume electrical resistivity, ultrasound reflection time, density, FE-SEM(field emission scanning electron microscopy), XPS(x-ray photoelectron spectroscopy), EDS(energy dispersive spectroscopy), and WD-XRF(wavelength dispersive x-ray fluorescence). A new condition monitoring methods of the accelerated thermal aging of CSPE cables were generally coincident with trend of indenter modulus expect EDS, XPS and XRF. A volume electrical resistivity among new condition monitoring methods of the accelerated thermal aging of CSPE cables is excellent. It is considered that life-time of CSPE cable can be predicted through volume electrical resistivity, if CSPE jacket was aged for period such as more than 20 years.

• Journal of Embryo Transfer
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• v.22 no.4
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• pp.209-212
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• 2007

This study was performed to establish the early pregnancy diagnosis with evaluation of size of embryonic vesicles and change of crown-rump length (CRL) by transrectal ultrasonography in the Korean black goats. Early pregnancy diagnosis was performed in the 114 goats from 19 to 35 days after coitus by transrectal 5.0 MHz transducer. Embryonic vesicles and CRL in the 142 goats from 19 to 42 days was measured to establish the correlation between gestational age and these parameters. The early pregnancy diagnosis achieved 80% accuracy after days 25 and 100% accuracy after days 28 after breeding. Diameters of embryonic vesicle and CRL were significantly increased with the gestational age. In these facts, early pregnancy diagnosis is possible on Days 25 after breeding and measurement of embryonic vesicles and CRL were useful to predict the gestational age in Korean black goat.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.469-478
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• 1996

In the conventional digital ultrasound scanner, the reflected signal is sampled either in polar coordinates of R-$\theta$ method, or in Cartesian coordinates of uniform ladder algorithm (ULA). The R-$\theta$ scan method necessitates a coordinate transform process which makes hardware complex in comparison with ULA scan mrthoA In spite of this complexity, R-$\theta$ method has a good resolution in ultrasonographic (US) image, since scan direction of the US imaging is a radial direction. In this paper, a new digital scan converter is proposed, which is named the radius uniform ladder algorithm (RULA). The RULA has the rome scan direction as the US scanning in the radial direction and as the display space in the $\theta$ direction. In tllis new approach, sampled points we uniformly distributed in each horizontal line i.n well as in each radial ray so that the data are displayed in the Cartesian coordinates by the 1-D interpolation process. The propped algorithm has an uniform resolution in the periphery and the center field in comparison with equi-angle ULA and equi-interval ULA. To extend the scan angle, concentric square raster sampling (CSRS) is adopted with reduction of discontinuities on the junctions between horizontal scan and vertical scan. The discontinuities are reduced by using the hmction filtering along the $\theta$ direction.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.466-471
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• 2011

Optical coherence tomography(OCT) is an emerging medical diagnostic tool that draws great attention in medical and biological fields. It has a 10-100 times higher spatial resolution than that of the clinical ultrasound but lower imaging depth such as 1-2 mm. In order to image internal organs, OCT needs an endoscopic probe. In this paper, the principle of Fourier-domain optical coherence tomography with high-speed imaging capability was introduced. An OCT endoscope based on MEMS technology was developed. It was attached to the Fourier-domain OCT system to acquire three-dimensional tomographic images of gastrointestinal tract of New Zealand white rabbit. The endoscope had a two-axis scanning mirror that was driven by electrostatic force. The mirror stirred an incident light to sweep two-dimensional plane by scanning. The outer diameter of the endoscope was 6 mm and the mirror diameter was 1.2 mm. A three-dimensional image rendered by 200 two-dimensional tomographs with $200{\times}500$ pixels was displayed within 3.5 seconds. The spatial resolution of the OCT system was 8 ${\mu}m$ in air.

• Journal of Veterinary Clinics
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• v.11 no.2
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• pp.529-537
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• 1994

Sector scanner which has a conical end is used to image through the intercostal space because heart is protected by the ribs. Cardiac data published all around the world were also obtained by sector scanner. Although scanners being used in every small animal practice and animal hospital at college in Korea include convex ape and linear type, linear type is not appropriate f3r cardiac scan because of a wide contact surface. The purpose of this study is to establish ultrasonographic images of normal cardiac structures by measuring shape, size of reflectable cardiac structure according to restraint position in scanning normal heart of the puppies with 6.5 MHz convex scanner(SonoAce 4500, Medison, Korea) used in our veterinary teaching hospital, Seoul national university. Seventeen male and female puppies considered having healthy hear by X-ray and clinical examination are used feom April to July 1994. Scanning point selection of probe head and the distinction of imaged cardiac structures were accomplished by necropsy and cardiac scanning performed through thoracotomy under general anesthesia. At 10 o'clock position of transducer(at an angle of 30$^{\circ}$ between imaginary line from elbow joint to 3rd sternum and probe head, 60$^{\circ}$ from body surface, 4th intercostal space of right thorax) with the marker of scanner toward the head of dogs right atrium, left atrium and left ventricle were observed in 2, 3, 4, 5 intercostal space(2cm from the sternum) of experimental dog positioned ventrodorsally under general anesthesia. Under these conditions, the numerical values of imaged diastolic hear are as follows : the distance from skin to apex(mean$\pm$S.D) 47.53$\pm$6.94mm, thickness of left ventricular wall 6.00$\pm$1.60mm, length of left ventricle 16.27$\pm$5.31mm, width of left ventricle 15,33$\pm$4.25mm, length of left atrium 12.33$\pm$3.82mm, width of left atrium 11. 33$\pm$3.94mm, length of right atrium 1.00$\pm$2.41mm, width of right atrium 11.21$\pm$2.76mm and the area of left ventricle 270.92$\pm$109.81mm$^2$, area of left atrium 98.00$\pm$41.08mm$^2$, area of right atrium 62.75$\pm$21.04mm$^2$.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.149-159
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• 2008

The purposes of this study are to analyze abnormal dilatation of the extrahepatic bile ducts by using transabdominal ultrasound, to confirm the existence of bile ducts diseases and their interrelationship, and for it to give a new theoretical basis for the technical access to extrahepatic bile ducts, upon which to analyze the ripple effects of the scan training. After teaching technical access process based on the new theory about extrahepatic bile duct to the thirty students who are studying ultrasonography, we allocated three hours per one student (30 mins ${\times}$ 6 times) to focus on the training of scanning skill. Training has been performed by one-to-one method. For evaluation, all the students have to perform the scans on (1) confluence of the right and left hepatic ducts (extrahepatic bile ducts and cystic duct), (2) the suprapancreatic bile duct, (3) the intrapancreatic bile duct, (4) intrapapilla Duct, based on the clearly divided concept. The existing training and methods have had low confidency about transabdominal ultrasonography of the extrahepatic bile duct and had limitation with which they could image only the suprapancreatic bile duct. The evaluation after finishing the train based on the new theory, however, all the students (30students) can access to (1) confluence of the right and left hepatic ducts(extrahepatic bile ducts and cystic duct), (2) the suprapancreatic bile duct objectively. 24 students can access to (3) the intrapancreatic bile duct and only one student can even make an image for (4) the intrapapilla Duct Though the evaluation on extrahepatic bile duct has to be performed with multi-sided method considering intrahepatic cause, bile duct cause and pathophysiological cause, only if we can image the extrahepatic bile duct to ampular of Vater objectively and confidently, we can greatly reduce invasive procedure such as ERCP, which is for the purpose of simple differential diagnosis and painful to the patients. Therefore if we concentrate on the scanning train based on the new theory to raise the confidency about ultrasonography, the effect will be doubled.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.61-65
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• 2008

Objective: To reduce urinary side effects in prostate cancer patients receiving radiation, patients were asked to drink certain amount of water to maintain bladder volume constant and the bladder volumes were measured weekly using ultrasound scanner. Materials and Methods: Twenty-six patients with prostate cancer who received radiation between December 2002 and August 2007 were enrolled in this study. Thirteen patients were enrolled in experimental group. These patients were asked to drink 450 cc of water, one hour prior to simulation, CT scan, and treatment. The other thirteen patients were given no information about bladder filing. Bladder, prostate, and rectum were contoured on CT and volumes were calculated. 3D conformal treatment planning was performed and effective volumes of bladder were calculated when a prescription dose of 70.2 Gy was delivered. For the patients in experimental group, bladder volumes were measured weekly using ultrasound scanner for 6-8 weeks and the bladder volume variations were analyzed. Results: Average bladder volumes and standard deviations obtained at CT scanning were $283.5{\pm}114.0\;cc$ (40%) and $181.2{\pm}120.1\;cc$ (66%) in experimental and control groups, respectively. Although it was not statistically significant, there was correlation between the bladder volumes measured from CT and ultrasound. The volumes measured using ultrasound scanner were 62% lower than the volumes using CT images on average. There was significant variations in volumes measured weekly for 6-8 weeks. It ranged between 33 - 75 %. Conclusion: Our results showed that it is possible to obtain larger bladder volume if they are asked to drink certain amount of water prior to CT scan. However, patients were unable to maintain constant bladder volumes over the 6-8 weeks of treatment period although they were asked to drink constant amount of water.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.507-512
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• 2017

The physicochemical properties of maize starch sonicated at various amplitudes (100, 200, and 300 W) and times (10, 30, and 50 min) were examined. The amount of enzyme-susceptible starch increased marginally after sonication. Sonication increased the amount of oil absorbed in the starch although the degree of oil absorption decreased with an extension of the sonication time, implied that different types and extent of damages occurred. Scanning electron microscopy revealed that ultrasound sonication did not form pores on the surfaces, but caused damages such as depression and erosion. Pasting viscosity of starch decreased with an increase in the severity of sonication conditions because of the weakened polymer network. X-ray diffraction suggested that the crystalline domains in starch were not susceptible to sonication and were more resistance to degradation. Sonicated starch formed more pin-holes on the surfaces in the initial glucoamylase reaction; subsequently, as the reaction proceeded, porous starch with enlarged pores was formed and finally, disrupted granular fragments were observed.

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.635-641
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• 2016

Objectives: The purpose of this study is to assess the characteristics of tooth surface after using Gracy curet and Ultrasonic scaler Methods: In this study, 12 teeth extracted were used. 12 specimens were divided into three groups with the same numbers, which were classified into Control group, Gracy curet use group, and Ultrasonic scaler use group, and after performing instrument operation, we measured the roughness and the loss degree of tooth surface by using SEM. Results: In groups using Gracy curet and Ultrasonic scaler, the roughness and the loss of tooth surface increased significantly(p<0.05). In the roughness of groups using Gracy curet and Ultrasonic scaler, Ultrasonic scaler group was higher in crown, but Gracy curet group was higher in root. As a result of observation through SEM, the roughness and the loss degree increased in order of Control group, Ultrasonic scaler use group, and Gracy curet use group. Conclusions: Taken together above results, both hand instrument and ultrasound equipment create roughness and loss in crown and in root, and hand instruments makes rougher than ultrasonic instruments in root, so it is thought to require thorough and accurate technical application not to damage tooth surface when removing plaque.

• Advances in Energy Research
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• v.2 no.1
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• pp.33-45
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• 2014

Photocatalytic hydrogen generation by water splitting ($H_2O_{(1)}{\rightarrow}H_2_{(g)}+1/2O_2_{(g)}$) has been studied on photocatalysts based on Zn, Cd, Fe and Cu, synthesized by coprecipitation. Iron and copper nanoparticles were incorporated as cocatalysts to enhance the photocatalytic activity of the ZnCd solid solution. The effect of the different synthesis parameters (temperature, elemental atomic ratios, amount of Cu and Fe incorporated in the catalyst and calcination temperature) on the photocatalytic production of hydrogen has been studied in order to determine the best experimental synthesis conditions. The catalysts have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and BET. The experiments of photocatalytic water splitting were performed in aqueous solution of the photocatalysts previously dispersed in a soft ultrasound bath. The photocatalysts were irradiated under different lights ranging from 220 to 700 nm. The photocatalytic activity was found to be clearly dependent on the specific area of the photocatalyst.