• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.231-236
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• 2004

An imaging plate(IP) detector, a two-dimensional digital radiation detector that can acquire image of radioactivity distribution in a sample, has been applied in many fields; for industrial radiography, medical diagnosis, X-ray diffraction test, etc. In this study, the possibility of IP detector to be used lot measuring radioactivity of sample is explored using its high sensitivity, higher spatial resolution, wider dynamic range and screen uniformity for several kinds radiations. First, the IP detector is applied to measure the surface uniformity for area source. Surface uniformity is measured rapidly and nondestructively by measuring the radioactivity distribution of common standard area source$(^{241}Am)$. Next, the IP is employed to study the possibility of measuring an extremely low-level activity of environmental sample. For this study the screen uniformity, shield effect of background radiation, linear dynamic range and fading effect of the IP detector is investigated. The potato, banana, radish and carrot samples are chosen to measure ultra low-level activity of $^{40}K$ isotope. The efficiency calibration of IP detector is carried out using the standard source.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.147-152
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• 2018

Recently, as the demand for transmission of ultra-high quality media data such as UHD, AR, and VR increases, various technologies for this have been actively developed and IEEE 802.11ad standard have been commercialized. In this paper, a test bed is constructed to analyze the indoor wireless environment using the IEEE 802.11ad standard based on mmWave, and the experimental results of various indoor wireless environments are introduced and analyzed. We compared the data from the module by data transmission, such as signal to noise ratio(SNR) and throughput. And we measured the beam pattern and width of the module and compared the effects on the indoor environment of the corridor and the office. This shows that the signal reflection of the wall shows higher SNR values and is more suitable to use for indoor than outdoor. It is confirmed that the loss when not in line of sight(LoS) is not enough to compensate the wall reflected signal. As a result, it is judged to be suitable for the indoor use of the mmWave LAN and can be usefully used for further experiments.

• Food Science and Preservation
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• v.23 no.1
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• pp.20-26
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• 2016

In this study, the anti-inflammatory effect of hyaluronidase (HAase) inhibition was determined from 92 species of oriental herbal medicine extracted with water and ethanol solvents because of their non-toxicity in the human body. The water extracts of Evodia officinalis (86.8%), Thuja orientalis (80.8%), Carthami semen (66.5%), Melia azedarach (74.7%), Siegesbeckia pubescens (61.3%), Saururus chinensis (49.15%) showed a relatively greater anti-inflammatory activity. The ethanol extracts of Ailanthus altissima and Saururus chinensis demonstrated the highest anti-inflammatory effect at above 90%. Saururus chinensis was selected for its high anti-inflammatory effect in both water and ethanol extract. Ethanol was more effective than water and optimal extraction conditions for phenolic compounds was determined to be extraction with 50% ethanol for 12 hours. The extracts from Saururus chinensis in optimal condition showed 70~80% anti-inflammatory effect when $100{\sim}250{\mu}g/mL$ phenolic concentration was treated. Concentration of above $500{\mu}g/mL$ decreased the inhibitory effect. The anti-inflammatory effect and extraction yield were increased by ultra-fine grind technology, indicating that this method can be used to increase the extraction yield of phenolic compounds from medicinal plants.

• Journal of Applied Biological Chemistry
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• v.59 no.4
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• pp.331-336
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• 2016

Analytical methods for methiozolin in soil, water and turfgrass were established and dissipation patterns of methiozolin in soil and turfgrass were elucidated. Analysis was done using a high performance liquid chromatography with an ultra violet detector at the wavelength of 280 nm after extraction with acetone, liquid-liquid partition with dichloromethane, and a solid phase extraction purification. Limit of determination and Limit of quantitation were 1.0, 0.5, 1.0 ng, and 0.001, 0.1, 0.01 mg/kg for water, turfgrass, and soil, respectively. Recovery rates of methiozolin from soil, water, and turfgrass were ranged 87.5~111.3, 92.8~97.4, and 78.2~98.5 %, respectively. The turfgrass and soil samples were collected at 0, 1, 4, 7, 14, 30, 45, and 60 after spray on green area in golf course. Residues of methiozlolin were not translocated to lower soil layer but detected only in turfgrasses and root area of turfgrass. Half-lives of methiozolin in turfgrass were 10.7 days and 8.8 days in soil from root area.

• Journal of Ginseng Research
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• v.41 no.4
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• pp.469-476
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• 2017

Background: Panax ginseng Meyer (Asian ginseng) has a large nuclear genome size of > 3.5 Gbp in haploid genome equivalent of 24 chromosomes. Tandem repeats (TRs) occupy significant portions of the genome in many plants and are often found in specific genomic loci, making them a valuable molecular cytogenetic tool in discriminating chromosomes. In an effort to understand the P. ginseng genome structure, we characterized an ultrahigh copy 167-bp TR (Pg167TR) and explored its chromosomal distribution as well as its utility for chromosome identification. Methods: Polymerase chain reaction amplicons of Pg167TR were labeled, along with 5S and 45S rDNA amplicons, using a direct nick-translation method. Direct fluorescence in situ hybridization (FISH) was used to analyze the chromosomal distribution of Pg167TR. Results: Recently, we reported a method of karyotyping the 24 chromosome pairs of P. ginseng using rDNA and DAPI (4',6-diamidino-2-phenylindole) bands. Here, a unique distribution of Pg167TR in all 24 P. ginseng chromosomes was observed, allowing easy identification of individual homologous chromosomes. Additionally, direct labeling of 5S and 45S rDNA probes allowed the identification of two additional 5S rDNA loci not previously reported, enabling the refinement of the P. ginseng karyotype. Conclusion: Identification of individual P. ginseng chromosomes was achieved using Pg167TR-FISH. Chromosome identification is important in understanding the P. ginseng genome structure, and our method will be useful for future integration of genetic linkage maps and genome scaffold anchoring. Additionally, it is a good tool for comparative studies with related species in efforts to understand the evolution of P. ginseng.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.205-214
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• 2012

Crack widths play an important role in the serviceability limit state. When crack widths are controlled sufficiently, the reinforcement corrosion can be reduced using only existing concrete cover thickness due to low permeability in the region of finely distributed hair-cracks. Thus, the knowledge about the tensile crack opening is essential in designing more durable concrete structures. Therefore, numerous researches related to the topic have been performed. Nevertheless accurate measurement of a crack width is not a simple task due to several reasons such as unknown potential crack formation location and crack opening damaging strain gages. In order to overcome these difficulties and measure precise crack widths, a displacement measurement system was developed using digital image correlation. Accuracy calibration tests gave an average measurement error of 0.069 pixels and a standard deviation of 0.050 pixels. Direct tensile test was performed using ultra high performance concrete specimens. Crack widths at both notched and unnotched locations were measured and compared with clip-in gages at various loading steps to obtain crack opening profile. Tensile deformation characteristics of concrete were well visualized using displacement vectors and full-field displacement contour maps. The proposed technique made it possible to measure crack widths at arbitrary locations, which is difficult with conventional gages such as clip-in gages or displacement transducers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.796-805
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• 2000

A 30GHz band low noise amplifier module, which has linear gain of 30dB and noise figure of 2.6dB, for 30GHz satellite communication transponder was developed by use of MMIC and thin film MIC technologies. Two kinds of MMIC circuits were used for the low noise amplifier module, the first one is ultra low noise MMIC circuit and the other is wideband and high gain MMIC circuit. The pHEMT technology with 0.15$mu extrm{m}$ of gate length was applied for MMIC fabrication. Thin film microstrip lines on alumina substrate were used to interconnect two MMIC chips, and the thick film bias circuit board were developed to provide the stabilized DC bias. The input interface of the low noise amplifier module was designed with waveguide type to receive the signal from antenna directly, and the output port was adopted with K-type coaxial connector for interface with the frequency converter module behind the low noise amplifier module. Space qualified manufacturing processes were applied to manufacture and assemble the low noise amplifier module, and space qualification level of environment tests including thermal and vibration test were performed for it. The developed low noise amplifier was measured to show 30dB of minimum gain, $\pm$0.3dB of gain flatness, and 2.6dB of maximum noise figure over the desired operating frequency range from 30 to 31 GHz.

• Journal of dental hygiene science
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• v.10 no.6
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• pp.445-450
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• 2010

The aim of this study was to evaluate the effect according to the fiber type and combination on the reinforcement of heat-polymerized denture base resin. The heat-polymerized resin(Vertex RS, Dentimax, Netherlands) was used in this study. Glass fiber(GL; ER 270FW, Hankuk Fiber Glass, Korea), polyaromatic polyamide fiber(PA; aramid; Kevlar-49, Dupont, U.S.A.) and ultra high molecular weight polyethylene fiber(PE, polyethylene; P.E, Dong Yang Rope, Korea) were used to reinforce the denture base resin specimens. The final size of test specimen was $64mm{\times}10mm{\times}3.3mm$. The specimens of each group were stored in distilled water at $37^{\circ}C$ for 50 hours before measurement. The flexural strength and flexural modulus were measured by an universal testing machine(Z020, Zwick, Germany) at a crosshead speed of 5 mm/min in a three-point bending mode. In this study, all fibers showed reinforcing effects on denture base resin(p<0.05). In terms of flexural strength and flexural modulus, glass fiber 5.3 vol.% showed most effective reinforcing effect on heat polymerized denture base resin. For flexural modulus, PA/GL was the highest in denture base resin specimen for hybrid FRC using two combination (p<0.05). Glass fiber 5.3 vol.% and PA/GL are considered to be applied effectively in reinforcing the heat polymerized denture base resin.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.403-415
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• 2014

Recently, the temperature rise in the summer due to climate change, power usage is increasing rapidly. As a result, power generation facilities have been newly completed and the need for ultra-high-voltage transmission line for power transmission of electricity to the urban area has increased. The mechanized tunnelling method using a shield TBM have an advantage that it can minimize vibrations transmitted to the ground and ground subsidence as compared with the conventional tunnelling method. Despite the popularity of shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Thus, in this study, the effect of fractured zone ahead of tunnel face on the mechanical behavior of the shield TBM cable tunnel is investigated. In addition, it is intended to compare the behavior characteristics of the fractured zone with continuous model and applying the interface elements. Tunnelling with shield TBM is simulated using 3D FEM. According to the change of the direction and magnitude of the fractured zone, Sectional forces such as axial force, shear force and bending moment are monitored and vertical displacement at the ground surface is measured. Based on the stability analysis with the results obtained from the numerical analysis, it is possible to predict fractured zone ahead of the shield TBM and ensure the stability of the tunnel structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.29-35
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• 2012

The treatments for spinal canal stenosis are radicular cyst removal, spine fusion, and implantation of an artificial intervertebral disc. Artificial intervertebral discs have been most widely used since the mid-2000s. The study of artificial intervertebral discs has been focused on the analysis of the axial rotation, lateral bending, the degrees of freedom of the disc, and flexion-extension of the vertebral body. The issue of fatigue failure years after the surgery has arisen as a new problem. Hence, study of artificial intervertebral discs must be focused on the fatigue failure properties and increased durability of the sliding core. A finite element model based on an in the artificial intervertebral disc (SB Charit$\acute{e}$ III) was produced, and the influence of the radius of curvature and the change in the coefficient of friction of the sliding core on the von-Mises stress and contact pressure was evaluated. Based on the results, new artificial intervertebral disc models (Models-I, -II, and -III) were proposed, and the fatigue failure behavior of the sliding core after a certain period of time was compared with the results for SB Charit$\acute{e}$ III.