• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1409-1412
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• 2014

Sex hormones are important metabolites in vertebrates' development and reproduction. For rapid screening sex hormones, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is one of the promising analytical platforms, but MALDI MS faces many challenges in detecting steroids such as low ionization efficiency and matrix background interference. One potential strategy to overcome matrix interference in the low m/z region is using a cyclodextrin (CD)-supported matrix for steroid analysis since CD-supported matrixes are known to effectively suppress matrix-related ion signals. In this study, we aimed to find the optimal CD-supported matrix for the analysis of the nonderivatized sex steroids. Our results showed that the ${\alpha}CD$-supported 2,5-dihydroxybenzoic acid (DHB) matrix efficiently ionized all three major classes of sex hormones, estrogens, androgens, and progestagens, with low or no matrix background and also with high sensitivity. In addition, the ${\alpha}CD$-supported DHB matrix mainly generated molecular ions or protonated ions of sex hormones, and this enabled us to obtain information-rich tandem mass spectra which potentially lead to unambiguous identification of steroid species from complex metabolite mixtures.

• KIEAE Journal
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• v.1 no.2
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• pp.47-54
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• 2001

Single sound absorbers such as porous materials, panels, and Helmholts resonators have limited performance with some extents of frequency region. For example, porous materials do not attenuate low frequency sounds, while panels do not absorb high frequency sounds. Composite absorption structure with coverings, porous materials, and air gaps are an alternative for wide band sound absorption. Slits, panels, perforated panels are those materials for coverings, glass wool, mineral wool, polyester, and polyurethane are frequently used porous materials. Air gap between the porous material and background surface is one of major factors which governs the absorption characteristics of composite absorption structures, especially in the low frequency area. Calculations and measurements show that the absorption coefficients of composite absorption structure, in mid and low frequency bands, are getting higher with increased air gaps. Perforated panels rather than slits and panels are good coverings with higher number as far as absorption coefficient is concerned. Perforated panels with porous materials and 37 cm of air gaps in background have high absorption coefficients for all frequency bands, above 0.7 to 1.0. All measurements are performed in reverberation chamber, Mokpo National University, according to ISO 354 and ISO 3382.

• The Research Journal of the Costume Culture
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• v.14 no.5
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• pp.776-789
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• 2006

The purpose of this study was to investigate the relationships between lifestyle types, demographic variables, and clothing consumption orientations of male and female adolescents. The method of this study was a survey research by using questionnaires. Subjects were 393 high school students in Seoul. Four lifestyle types of adolescents were derived by cluster analysis: 'digital orientation type', 'material orientation type', 'positive enterprise type', and 'achievement orientation type'. The material oriented students spent high expense on clothes, had higher preference of imported products, had more sensuous consumption orientations, did more impulsive buying, and were more influenced by advertisements than other types of students. Digital oriented students had mothers with low educational background, low academic records, spent small expense on clothes, and had less sensuous consumption orientation. There were more male students than female students in positive enterprise type and the students of this type had upper middle academic records, had higher sensuous consumption orientation and did less impulsive buying. There were more female students than male students in achievement oriented type and this type had high academic records, had mothers with high educational background, and spent small expense on clothes. They had low level on most of the clothing consumption orientation and were especially less influenced by advertisement. This research confirms that the clothing consumption orientations are associated with the lifestyle of adolescent.

• Ocean and Polar Research
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• v.44 no.4
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• pp.287-296
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• 2022

High-frequency (HF) radar measures sea surface currents from the radio waves transmitted and received by antenna on land. Since the data quality of HF radar measurements sensitively depend on the radio wave environment around antenna, Antenna Pattern Measurements (APM) plays an important role in evaluating the accuracy of measured surface currents. In this study, APM was performed by selecting the times when the background noise level around antenna was high and low, and radial data were generated by applying the ideal pattern and measured pattern. The measured antenna pattern for each case was verified with the current velocity data collected by drifters. The radial velocity to which the ideal pattern was applied was not affected by the background noise level around antenna. However, the radial velocity obtained with APM in the period of high background noise was significantly lower in quality than the radial velocity in a low noise environment. It is recomended that APM be carried out in consideration of the radio wave environment around antenna, and that the applied result be compared and verified with the current velocity measurements by drifters. If it is difficult to re-measure APM, we suggest using radial velocity in generating total vector with the ideal pattern through comparative verification, rather than poorly measured patterns, for better data quality.

• Journal of KSNVE
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• v.9 no.1
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• pp.85-96
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• 1999

For ASME Code pumps in nuclear power plants, inservice test is required to assess the operational readiness in accordance with ASME code and related regulations. The objective of this study therefore, is to develop the technical background of the degradation of pump performances and conditions due to low flow rate operation. In addition. the detection techniques of pump operating conditions are to be developed to enhance the safety and economy of nuclear power plants. A test loop consisted of pump, motor. water tank, flow rate measurements and piping system with flow control devices was established for this study. Two typical pumps, 1-stage volute pump and 3-stage turbine pump, were selected and the test was performed upon two major point of views ; i.e., pump discharge pressure pulsations analysis and pump vibration spectrum analysis. From the test results, it is concluded that (1) the pump vibration affected by the natural frequency of operating pump is significant in the low frequency zone (around 1 Hz) : the vibration amplitude. especially. is an important factor during low flow rate operation. and shall be monitored to ensure that it is within the limit of ASME OM code Part 6, (2) the vibration frequency and pump discharge pressure are affected by vane pass frequency and running speed, (3) the wave phenomena due to the compressiblity of water is anticipated during low flow rate operation. and the pump system shall be designed to prevent it and. finally, (4) the technical background of the degradation of pump performances and conditions due to low flow rate operation is provided.

• Atmosphere
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• v.20 no.3
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• pp.307-318
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• 2010

This study investigates the generation and movement of low-concentration $CO_2$ observed in Gosan during summer from 2002 to 2006. For analysis, additional $CO_2$ data in Anmyeondo, Ryori, Barrow, and Minamitorishima as well as NOAA/ESRL daily global $CO_2$ fields, background trajectories data, and 850 hPa wind fields are also used. Based on analyses using various observed data, we classified three types of low-concentration $CO_2$ in Gosan according to its origin: i) the origin of the Siberian continental, in which the consumption of $CO_2$ is active due to photosynthesis from broad forests, ii) the origin of Okhotsh and Artic seas, in which the low-concentration $CO_2$ is dominant due to high primary productivity by a plankton bloom, and iii) the origin of the Northwestern Pacific which is related to the entry of air mass from high latitudes. These results show that the low-concentration $CO_2$ observed in Gosan during summer is not originated from the Pacific oceans as known in previous studies, but originated from high latitude regions such as the Siberian continental and the Okhotsh and Artic seas.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.419-424
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• 2004

Various radiation counters have been using to determine radioactivity of radwastes for disposal. A radiation counting system was set up using a radiation detector chosen in this study and its stability was investigated through the periodic determination of background and counting efficiencies in accordance with a quality control program to increase the confidence level. The average background level for the $\gamma$-spectrometer was 1.59 cps and the average counting level for the standard sample was 45248 Ops within $2{\sigma}$ confidence levels. The average alpha background level for the low background ${\alpha}{\beta}$ counting system was 0.31 cpm and the efficiency for alpha counting was 34.38%. The average beta background level for the ${\alpha}{\beta}$ counting system was 1,30 cpm and the efficiency for beta counting was 46.5%, The background level in the region of 3H and 14C for the liquid scintillation counting system was 2.52 and 3.31 cpm and the efficiency for alpha counting was 58.5 and 95.6%, respectively. The minimum detectable activity for the$\gamma$-spectrometer was found to be 3.2 Bq/$m\ell$ and 3.8 Bq/$m\ell$ for the liquid scintillation counter, and 20.5 and 23.0 Bq/$m\ell$, respectively for the $\alpha$ and $\beta$ counting system.

• The Korean Journal of Pain
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• v.23 no.2
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• pp.147-150
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• 2010

Background: Chronic low back pain can be a manifestation of lumbar degenerative disease, herniation of intervertebral discs, arthritis, or lumbar stenosis. When nerve roots are compromised, low back pain, with or without lower extremity involvement, may occur. Local inflammatory processes play an important role in patients with acute lumbosciatic pain. The purpose of this study was to assess the value of erythrocyte sedimentation rate (ESR) and high sensitivity C-reactive protein (hsCRP) measurements in patients with chronic low back pain or radiculopathy. Methods: ESR and hsCRP were measured in 273 blood samples from male and female subjects with low back pain and/or radiculopathy due to herniated lumbar disc, spinal stenosis, facet syndrome, and other diseases. The hsCRP and ESR were measured prior to lumbar epidural steroid injection. Results: The mean ESR was 18.8 mm/h and mean hsCRP was 1.1 mg/L. ESR had a correlation with age. Conclusions: A significant systemic inflammatory reaction did not appear to arise in patients with chronic low back pain.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.771-788
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• 2020

Detection of abandoned objects for smart video surveillance should be robust and accurate in various situations with low computational costs. This paper presents a new algorithm for abandoned object detection based on the dual background model. Through the template registration of a candidate stationary object and presence authentication methods presented in this paper, we can handle some complex cases such as occlusions, illumination changes, long-term abandonment, and owner's re-attendance as well as general detection of abandoned objects. The proposed algorithm also analyzes video frames at specific intervals rather than consecutive video frames to reduce the computational overhead. For performance evaluation, we experimented with the algorithm using the well-known PETS2006, ABODA datasets, and our video dataset in a live streaming environment, which shows that the proposed algorithm works well in various situations.

• Journal of The Korean Astronomical Society
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• v.35 no.2
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• pp.67-73
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• 2002

We have made a topological study of cosmic microwave background (CMB) polarization maps by simulating the AMiBA experiment results. A ACDM CMB sky is adopted to make mock interferometric observations designed for the AMiBA experiment. CMB polarization fields are reconstructed from the AMiBA mock visibility data using the maximum entropy method. We have also considered effects of Galactic foregrounds on the CMB polarization fields. The genus statistic is calculated from the simulated Q and U polarization maps, where Q and U are Stokes parameters. Our study shows that the Galactic foreground emission, even at low Galactic latitude, is expected to have small effects on the CMB polarization field. Increasing survey area and integration time is essential to detect non-Gaussian signals of cosmological origin through genus measurement.