• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.5
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• pp.429-436
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• 2010

Recently, (terahertz ray) applications have emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques. In this study, a new T-ray time-domain spectroscopy system was utilized for detecting and evaluating layup effect and flaw in FRP composite laminates. Extensive experimental measurements in reflection and thru-transmission modes were made to map out the T-ray images. Especially this was demonstrated in thick GFRP laminates containing double saw slots. In carbon composites the penetration of terahertz waves is limited to some degree and the detection of flaws is strongly affected by the angle between the electric field(E-field) vector of the terahertz waves and the intervening fiber directions. The artificial defects investigated by terahertz waves were bonded foreign material, simulated disbond and delamination and mechanical impact damage. The effectiveness and limitations of terahertz radiation for the NDE of composites are discussed.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.35.4-36
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• 2018

$Ly{\alpha}$ blobs are mysterious, giant (~100 kpc), glowing gas clouds in the distant universe. They occupy the dark matter halos that will evolve into the richest groups and clusters today. The blob's gas may be the proto-intracluster medium and their embedded galaxies are considered as the progenitors of massive cluster galaxies. Yet we do not know why $Ly{\alpha}$ blobs glow. There are evidences of kinematic measurements to exclude shocks and winds from AGN or starbursts as a power source, suggesting that photoionizing radiation or scattering of $Ly{\alpha}$ photons might be responsible. Polarization mapping can discriminate between these photo-ionization and scattering. Previous results of imaging polarimetry for $Ly{\alpha}$ nebulae are roughly consistent with scattering models. However the polarization morphologies in those of previous results are all different, motivating our polarimetric survey of $Ly{\alpha}$ nebulae for the statisticallymeaningful sample. As initial results of our survey, we present the total polarization map of the LABd05 which has the spatial offset between the peak of $Ly{\alpha}$ surface brightness and an obscured AGN. We detect the significant polarization in this target with the radially increasing polarization gradient, suggesting that scattering plays major role within this nebula. The polarization pattern is more aligned with the $Ly{\alpha}$ peak rather than the AGN (the potential energy source), indicating that the $Ly{\alpha}$ photons are originated from the region near the peak of $Ly{\alpha}$ intensity.

• Journal of Korean Elementary Science Education
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• v.30 no.4
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• pp.468-481
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• 2011

This research is to observe and analyze the student interactions when inquiry problems were generated along with the students by using asynchronous discussion methods with the class bulletin board. For this research, 10 students from a single class of 6th grade were selected. The subject students were divided into 2 groups by cognitive levels. After the students were submitted the 4 problem situations for 1 week each, the discussion process was analyzed. The research results are as follows. First, the analysis of the step by step interactive discussion showed that several students answered for the question from a single student while discussing first for the question and answer in a form of a question with many multiple answers without any connections with the previously asked questions. At the end of the discussion, one to two students answered to a question by taking turns and the type of discussion changed to one question - one answer type by answering to the person who spoke prior to the next. Second, the discussion took place with the students in the transitional stage speaking in time in order, to provide comments to the bottom of the linear form and students in the formal operational stage students speaking in temporal order, regardless of the number of comments in the direction of the radiation(mind map) forms. The individual comment speaking rates were similar in the two groups so the students were able to speak indiscriminately.

• BMB Reports
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• v.41 no.6
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• pp.466-471
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• 2008

Three isoforms of pig PDE4B were cloned and classified as two forms: PDE4B1 and PDE4B3, which contain UCR1 and UCR2; and PDE4B2, which contains only UCR2. The amino acid sequences of each isoform showed good conservation in human and rat. PDE4B2 is expressed in a wide range of tissues, but PDE4B1 and PDE4B3 are not. Using an informative SNP for the Iberian x Landrace intercross detected from intron 12, a linkage map was constructed. The location of PDE4B was estimated at 123.6 cM outside of the QTL-CI (124-128 cM) for IMF. However, the QTL-CI for IMF was reconfirmed with high significance, and its position was narrowed down to an interval of 4 cM (the region defined by markers PDE4B and SW1881). Using radiation hybrid mapping, LEPR, LEPROT, DNAJC6, AK3L1 and AK3L2 were selected as positional and/or functional candidates related to the QTL.

• Progress in Medical Physics
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• v.23 no.4
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• pp.303-308
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• 2012

The Geant4 based Monte Carlo code for the application of stereotactic radiosurgery was developed. The probability density function and cumulative density function to determine the incident photon energy were calculated from pre-calculated energy spectrum for the linac by multiplying the weighting factors corresponding to the energy bins. The messenger class to transfer the various MLC fields generated by the planning system was used. The rotation matrix of rotateX and rotateY were used for simulating gantry and table rotation respectively. We construct accelerator world and phantom world in the main world coordinate to rotate accelerator and phantom world independently. We used dicomHandler class object to convert from the dicom binary file to the text file which contains the matrix number, pixel size, pixel's HU, bit size, padding value and high bits order. We reconstruct this class object to work fine. We also reconstruct the PrimaryGeneratorAction class to speed up the calculation time. because of the huge calculation time we discard search process of the ThitsMap and used direct access method from the first to the last element to produce the result files.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.107.1-107.1
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• 2012

We present the results of far-ultraviolet (FUV) observations of comet C/2001 Q4 (NEAT) obtained with Far-ultraviolet Imaging Spectrograph (FIMS) on board the Korean microsatellite STSAT-1, which operated at an altitude of 700 km in a sun-synchronous orbit. FIMS is a dual-channel imaging spectrograph (S channel 900-1150 ${\AA}$, L channel 1350-1750 ${\AA}$, ${\lambda}/{\Delta}{\lambda}$ ~ 550) with large image fields of view (S: $4^{\circ}.0{\times}4^{\prime}.6$, L: $7^{\circ}.5{\times}4^{\prime}.3$, angular resolution 5'-10') optimized for the observation of diffuse emission of astrophysical radiation. Comet C/2001 Q4 (NEAT) was observed with a scanning survey mode when it was located around the perihelion between 8 and 15 May 2004. Several important emission lines were detected including S I (1425, 1474 ${\AA}$), C I (1561, 1657 ${\AA}$) and several emission lines of CO $A^1{\Pi}-X^1{\Sigma}^+$ system in the L channel. Production rates of the notable molecules, such as C I, S I and CO, were estimated from the photon fluxes of these spectral lines and compared with previous observations. We compare the flux and the production rates in the radius of $3{\times}10^5$ km with $20{\times}10^5$ km from the central coma. We obtained L-channel image which have map size $5^{\circ}{\times}5^{\circ}$ The image was constructed for the wavelength band of L-channel (1350 - 1710 ${\AA}$. We also present the radial profiles of S I, C I, CO obtained from the spectral images of the central coma. The radial profiles of $2{\times}10^6$ km region are compared with the Haser model.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.721-730
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• 1999

A Grid-based daily evapotranspiration(ET) prediction model which calculates temporal and spatial ET with a complementary relationship of Morton(1983) was developed. The model was programmed by C-language and uses ASCII formatted map data of DEM(Digital Elevation Model) and land use. Daily ET within the watershed is calculated and the results of temporal variations and spatial distributions of ET are presented by using GRASS(Geographic Resources Analysis Support System). To verify the applicability of the model, it was applied to the part of Bocheong stream basin (76.5$\textrm{km}^2$) located in the upstream of Dacheong Dam watershed. The result shows that the estimated evapotranspiration in 1995 was 766.1mm and 22% increased after correction radiation for slope and area.

• Safety and Health at Work
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• v.12 no.2
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• pp.201-208
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• 2021

Background: In the mining industry, various methods of accident analysis have utilized official accident investigations to try and establish broader causation mechanisms. An emerging area of interest is identifying the extent to which cultural influences, such as safety culture, are acting as drivers in the reoccurrence of accidents. Thus, the overall objective of this study was to analyze occupational health and safety (OHS) reports in mining to investigate if/how safety culture has historically been framed in the mining industry, as it relates to accident causation. Methods: Using a computer-assisted qualitative data analysis software, 34 definitions of safety culture were analyzed to highlight key terms. Based on word count and contextual relevance, 26 key terms were captured. Ten OHS reports were then analyzed via an inductive thematic analysis, using the key terms. This analysis provided a concept map representing the 50-year data set and facilitated the use of text framing to highlight safety culture in the selected OHS mining reports. Results: Overall, 954 references and six themes, safety culture, attitude, competence, belief, patterns, and norms, were identified in the data set. Of the 26 key terms originally identified, 24 of them were captured within the text. The results made evident two distinct frames in which to interpret the data: the role of the individual and the role of the organization, in safety culture. Conclusion: Unless efforts are made to understand and alter cultural drivers and share these findings within and across industries, the same accidents are likely to continue to occur.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.2
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• pp.119-125
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• 2022

In this paper, we present design, implementation and test results of CTM (Chirp Transceiver Module) EM (Engineering Model) for C-Band SAR (Synthetic Aperture Radar) Payload. The CTM is designed to operate dual frequency scan method that simultaneously operate two frequencies in each 50MHz bandwidth to achieve 120Km swath with 10m resolution at about 500Km altitude. The CTM used radiation tolerant RTG4 FPGA for space environment, and implemented with the Parallel DDS (PDDS) method which uses a small memory capacity compared to the memory-map method. Test results show high purity chirp signal generation and excellent IRF performance from received chirp signal after direct digital conversion.

• Korean Journal of Radiology
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• v.25 no.1
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• pp.24-32
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• 2024

Despite improvements in operative techniques and perioperative care, post-hepatectomy liver failure (PHLF) remains the most serious cause of morbidity and mortality after surgery, and several risk factors have been identified to predict PHLF. Although volumetric assessment using imaging contributes to surgical simulation by estimating the function of future liver remnants in predicting PHLF, liver function is assumed to be homogeneous throughout the liver. The combination of volumetric and functional analyses may be more useful for an accurate evaluation of liver function and prediction of PHLF than only volumetric analysis. Gadoxetic acid is a hepatocyte-specific magnetic resonance (MR) contrast agent that is taken up by hepatocytes via the OATP1 transporter after intravenous administration. Gadoxetic acid-enhanced MR imaging (MRI) offers information regarding both global and regional functions, leading to a more precise evaluation even in cases with heterogeneous liver function. Various indices, including signal intensity-based methods and MR relaxometry, have been proposed for the estimation of liver function and prediction of PHLF using gadoxetic acid-enhanced MRI. Recent developments in MR techniques, including high-resolution hepatobiliary phase images using deep learning image reconstruction and whole-liver T1 map acquisition, have enabled a more detailed and accurate estimation of liver function in gadoxetic acid-enhanced MRI.