• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.2
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• pp.138-149
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• 2000

Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi mode conversion of guided wave scattering problems. Time dependent wave forms are obtained through the inverse Fourier transformation of the numerical solutions in the frequency domain. 3D BEM program development is underway to model more practical ultrasonic wave signals. Some encouraging numerical results have recently been obtained in comparison with the analytical solutions for wave propagation in a bar subjected to time harmonic longitudinal excitation. It is expected that the presented modeling techniques for elastic wave propagation and scattering can be applied to establish quantitative nondestructive evaluation techniques in various ways.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.857-862
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• 2004

Effects of frying temperature and time, presoaking in distilled water, various pH buffer solutions, and storage temperature of french fries on acrylamide formation were investigated. Acrylamide concentration in french fries increased as frying temperature and time increased. Presoaking of raw potatoes in distilled water reduced acrylamide formation compared to those without presoaking. Acrylamide formation of fried potatoes after presoaking at $60^{\circ}C$ for 45 min was about 16% of that without presoaking. Presoaking treatment of raw potatoes in various buffer solutions showed acrylamide concentrations of french fries from potatoes presoaked in acidic buffer solutions were lower than those from potatoes presoaked in neutral to alkaline buffer solutions. Acrylamide concentration of potatoes stored at refrigerator temperature was much higher than those stored at room temperature.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.37-47
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• 2009

This study develops a technique training program to enhance the completion of Kolman, the high air flight technique, and applies it to two national athletes of the horizontal bar, one of the gymnastic events, for eight weeks. After that, their improvement was measured through 3D motion analysis to help them elevate their performance. The training program includes swing, hand release, twist, and bar hold, and its implementation produced the results stated below. They were made to practice the motion in the following way. After the hand-standing of giant swing which initiates the motion, they lift their body upward a little bit more. Next, they take their body down almost like a vertical descent and make a deep tap swing. Instead of doing the tap swing which widens the flection of hip and shoulder joints, while body revolution is more emphasized in particular, they release the bar as raising the centroid of their body sufficiently. During the flight, they try to narrow every joint in their body. As a result, the bar's elasticity becomes greatly increased, and since the backing rate of their body gets higher, the centripetal force of the swing is improved that they can release the bar in the higher position. In addition, because they can erect their body faster during the flight, they can perform comfortable twist and revolution in the air. They can also adjust the direction of the flight easily without too much concern for the proper timing of hand release as they rise. Thereby, they can not only maintain adequate distance from the bar for the bar hold but also ensure enough distance for body revolution and twist.

• Journal of Technology Innovation
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• v.21 no.2
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• pp.1-24
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• 2013

In spite of the increasing importance of service sector, most previous studies on schumpeterian hypotheses originated from manufacturing firms that have the needs to invest heavily in research and development (R&D). Conversely, we investigated the relationship between technological innovation activity and size of firms using panel data. Results of the analysis, the following results were obtained. First, the details depending on the industry sector was divided into active and vigorous industry technology innovation activities did not. Second, the relationship between firm size and technological innovation activity may not be, depending on the industry, some of the U-shaped model, may be. Third, showed fewer intangible assets, more debt, larger exports which further promote the technological innovation activities in industry. Finally, the relationship is responsive depend on the firm size variable.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.59-65
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• 2002

Different amounts of the Opuntia ficus-indica var. saboten fruit were soaked in different alcohol concentrations of a Korean rice wine distillate for 4 months. Changes in pH, brix degree, contents of reducing sugar and polyphenol compound, alcohol concentration, turbidity, and color were analyzed during the soaking period. Quality of the final product was determined through the analysis of the volatile flavor compounds and sensory evaluation. During the soaking periods, pH, alcohol concentration, and contents of polyphenol compound decreased, whereas the content of reducing sugar increased. These changes were affected more by the content of the fruit than the alcohol concentration of the soaking media. Turbidity of the wine increased with higher fruit contents, while the increase of alcohol concentration resulted in the turbidity decrease. As the soaking period increased, lightness and yellowness increased but redness decreased. Acetaldehyde, acetyl acetone, ethyl alcohol, guaiacol, thymol, and acetic acid phenyl ester were detected in all liquors. Significant differences in all sensory attributes test were shown by six experimental groups (p<0.05), and the best overall acceptability was obtained from the liquor made of 67% fruits and 30% alcohol concentration.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.163-172
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• 2004

Mast cells (MCs) have been implicated in the pathogenesis of tissue fibrosis. However, the role of MC in the development of liver fibrosis has not been fully elucidated. Stem cell factor (SCF) is known to recruit MCs to the liver following injury as it induces mast cell proliferation, survival and differentiation from resident tissue precursors. This study examines the interaction between activated hepatic stellate cells (HSCs) and MCs in rat fibrotic liver, and SCF production by HSCs during culture in vitro. Rats were studied 4, 7, 14 and 21 days after bile duct ligation (BDL). Fibrogenesis was assessed by a measurement of collagen stained with sirius red F3B. Activated HSCs and MCs were identified by ${\alpha}$-smooth muscle actin (${\alpha}-SMA$) immunohistochemical and alcian blue staining and measured by a computerized image analysis system. SCF production was determined in rat HSC cultures using Western blotting. Mild fibrotic changes were noted in BDL rat livers as early as 4 days after induction of cholestasis. Significant expansion and organization of fibrous tissue has occurred in day 14 BDL rats which progressed to bridging fibrosis by day 21. In BDL rats, both a large number of activated HSCs and MCs were detected in portal tracts and fibrous septa. Both area of activated HSCs infiltration and density of MCs were significantly higher in all BDL group compared with Shams. In BDL rats, both areas of activated HSCs infiltration and density of MCs were no significant difference between day 4 and 7 and were significantly higher in day 14. However, the areas of activated HSCs infiltration were significantly lesser in day 21 and the densities of MCs were significantly higher in day 21 compared with day14 BDL. In BDL rats, both areas of activated HSCs infiltration and density of MCs were highly correlated with areas of fibrosis. Western blotting showed that SCF protein was consistently produced in activated HSCs by culture on plastic and freshly isolated HSCs expressed relatively little 30kD SCF compared to late primary culture activated HSCs (day 14) and passaged HSCs. These results suggest that HSCs activated in vitro produce SCF, and may play an important role in recruiting mast cells to the liver during injury and fibrosis.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.590-603
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• 2006

Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.

• Economic and Environmental Geology
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• v.46 no.6
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• pp.495-508
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• 2013

Recently, stable isotopes (${\delta}^{18}O$ and ${\delta}D$) of water are increasingly analyzed using laser-based technologies. These methods have advantages over Isotope Ratio Mass Spectrometry (IRMS) in that they can be used for in-situ measurements and require much less maintenance and preparation work. Two types of laser-based methods are currently available, which have different analytical principles; OA-ICOS (off-axis integrated cavity output spectroscopy) and WS-CRDS (wavelength-scanned cavity ring-down spectroscopy). In the WS-CRDS instrument, water is vaporized at controlled environment and transferred to an optical cavity by nitrogen carrier gas, and stable isotopic compositions of water vapor are measured using the degree of absorbance of specific wavelengths and the ratios of attenuation time of the laser intensity with the sensitivity of ppb to tens of ppt level. In this study, we introduce the principle of the WS-CRDS technology and the performance results including stability and comparisons with Isotope Ratio Mass Spectrometry (IRMS) and suggest possible applications of various topics in isotope hydrology.

• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.13-18
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• 2015

Purpose : Skip the repetitive HRCT axial scan in order to reduce the exposure of patients during chest HRCT scan, Helical Scan Data into a reconstructed image, and exposure of the patient change and visually evaluate the usefulness of the HRCT images. Materials and method : Patients were enrolled in the survey are 50 people who underwent chest CT scans of patients who presented to the hospital from January 2015 to March 2015. 50 people surveyed 22 people men and 28 people women people showed an average distribution of 30 to 80 years age was 48 years. 50 patients to Somatom Sensation 64 ch (Siemens) model with 120 kVp tube voltage to a reference mAs tube current to mAs (Care dose, Siemens) as a whole, including the lungs and the chest CT scan was performed. Scan upon each patient CARE dose 4D (Automatic exposure control, Siemens Medical Solution Erlangen, Germany) was to maintain the proper radiation dose scan every cross-section through a device that automatically adjusts the tube current of. CT scan is the rotation time of the Tube slice collimation, slice width 0.6 mm, pitch factor was made under the terms of 1.4. CT scan obtained after the raw data (raw data) to the upper surface of the axial images and coronal images for each slice thickness 1 mm, 5 mm intervals in the high spatial frequency calculation method (hight spatial resolution algorithm, B60 sharp) was the use of the lung window center -500 HU, windows were reconstructed into images in the interval -1000 HU to see. Result : 1. Measure the total value of DLP 50 patients who proceed to chest CT group A (Helical Scan after scan performed with HRCT) and group B (Helical Scan after the HR image reconstruction to the original data) compared with the group divided, analysis As a result of the age, but show little difference for each age group it had a decreased average dose of about 9%. 2. A Radiation read the results of the two Radiologist and a doctor upper lobe and middle lobe of the lung takes effect the visual evaluation is not a big difference between the two images both, depending on the age of the patient, especially if the blood vessels of the lower lobe (A: 3.4, B: 4.6) and bronchi(A: 3.8, B4.7) image shake caused by breathing in anxiety (blurring lead) to the original data (raw data) showed that the reconstructed image is been more useful in diagnostic terms. Conclusion : Scan was confirmed a continuous, rapid motion video to get Helical scan is much lower lobe lung reduction in visual blurring, Helical scan data to not repeat the examination by obtaining HRCT images reorganization reduced the exposure of the patient.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.841-846
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• 2003

Landrace(L), Largewhite(Lw), Korean Native Pig(KNP) and commercial hybrid were experimented to determine holothane sensitivity, RYR gene mutation and quality profiles. In the results of halothane test, the incidence of halothane positive pigs was similar between L and Lw. But, the rate of dubious halothane positive type was higher in L than Lw. In hal-gene analysis, halothane-positive pigs(nn) were not found in any tested breed and heterotype(Nn) appeared only in one pig of L. Of the breed effect on the quality profiles, there were no differences in pH$_1$(pH at 1hr postslaughter), but pH$_{u}$(pH at 24hr postslaughter) was significantly higher in commercial hybrid and KNP than other breeds(p〈0.05). Color assessed by National Pork Producers Council(NPPC) and CIE L$^{*}$ was significantly paler in L breed than other breeds(p〈0.05). Significant differences were found in water holding capacity(WHC) and cooking loss in KNP(p〈0.05).