Kim S.J.,Gyeonggi Science High School |
Yoo Y.J.,Hanyang University |
Kim Y.J.,Hanyang University |
Lee Y.,Hanyang University
Optics Communications | Year: 2017
In the general metamaterial absorber, the single absorption band is made by the single meta-pattern. Here, we introduce the triple-band metamaterial absorber only utilizing single rectangular hole. We also demonstrate the absorption mechanism of the triple absorption. The first absorption peak was caused by the fundamental magnetic resonance in the metallic part between rectangular holes. The second absorption was generated by induced tornado magnetic field. The process of realizing the second band is also presented. The third absorption was induced by the third-harmonic magnetic resonance in the metallic region between rectangular holes. In addition, the visible-range triple-band absorber was also realized by using similar but smaller single rectangular-hole structure. These results render the simple metamaterials for high frequency in large scale, which can be useful in the fabrication of metamaterials operating in the optical range. © 2016 Elsevier B.V.
Chung B.,Pohang University of Science and Technology |
Shin G.W.,Pohang University of Science and Technology |
Hwang H.S.,Pohang University of Science and Technology |
Chung Y.-J.,Catholic University of Korea |
And 2 more authors.
Analytical Biochemistry | Year: 2012
The H1N1 influenza virus has spread worldwide to become pandemic. Here, we developed a new method to discriminate various types of influenza A, including H1N1, using stuffer-free multiplex ligation-dependent probe amplification based on a conformation-sensitive separation method, namely capillary electrophoresis-single-strand conformation polymorphism. Unlike conventional methods, our approach precisely detects five relevant gene markers permitting confirmation of infection. © 2012 Elsevier Inc. All rights reserved.
PubMed | Sungkyunkwan University and Gyeonggi Science High School
Type: Journal Article | Journal: Archives of pharmacal research | Year: 2015
Deep eutectic solvents (DESs) were investigated as tunable, environmentally benign, yet superior extraction media to enhance the extraction of anthocyanins from grape skin, which is usually discarded as waste. Ten DESs containing choline chloride as hydrogen bond acceptor combined with different hydrogen bond donors were screened for high extraction efficiencies based on the anthocyanin extraction yields. As a result, citric acid, D-(+)-maltose, and fructose were selected as the effective DES components, and the newly designed DES, CM-6 that is composed of citric acid and D-(+)-maltose at 4:1 molar ratio, exhibited significantly higher levels of anthocyanin extraction yields than conventional extraction solvents such as 80% aqueous methanol. The final extraction method was established based on the ultrasound-assisted extraction under conditions optimized using response surface methodology. Its extraction yields were double or even higher than those of conventional methods that are time-consuming and use volatile organic solvents. Our method is truly a green method for anthocyanin extraction with great extraction efficiency using a minimal amount of time and solvent. Moreover, this study suggested that grape skin, the by-products of grape juice processing, could serve as a valuable source for safe, natural colorants or antioxidants by use of the eco-friendly extraction solvent, CM-6.
Cheong Y.W.,Gyeonggi Science High School |
Lee S.-W.,Seoul National University
Physical Review Letters | Year: 2012
We derive a tight bound between the quality of estimating a quantum state by measurement and the success probability of undoing the measurement in arbitrary dimensional systems, which completely describes the tradeoff relation between the information gain and reversibility. In this formulation, it is clearly shown that the information extracted from a weak measurement is erased through the reversing process. Our result broadens the information-theoretic perspective on quantum measurement as well as provides a standard tool to characterize weak measurements and reversals. © 2012 American Physical Society.
Oh H.J.,Seoul National University |
Park E.J.,Seoul National University |
Lee S.Y.,Gyeonggi Science High School |
Soh J.W.,Gyeonggi Science High School |
And 5 more authors.
Cell Proliferation | Year: 2012
Objectives: This study compared rate of cell proliferation, viability, cell size, expression patterns of genes related to pluripotency and epigenetic modification between canine foetal fibroblasts (cFF) and canine adipose tissue-derived mesenchymal stem cells (cAd-MSC). Materials and methods: Proliferation pattern, cell viability as well as cell size at each passage of cFF and cAd-MSC were measured when cultures reached confluence. In addition, real-time PCR was performed to investigate expression of Dnmt1, HDAC1, OCT4, SOX2, BAX, BCL2 genes with reference to β-actin gene expression as an endogenous control in both cell lines. Results: cFF and cAd-MSC differed in number of generations, but not in doubling times, at all passages. Mean cell size of cAd-MSC was significantly smaller than that of cFF. Cell viability was significantly lower in cFFs and apoptotic level was significantly lower in cAd-MSC compared to passage-matched cFF. In the expression of genes related to pluripotency and epigenetic modification, level of HDAC1 in cAd-MSC was significantly higher than in cFF, but expression of Dnmt1 did not differ between the two groups. OCT4 and SOX2 were significantly more highly expressed in cAd-MSC compared to cFF. Conclusions: cAd-MSC have higher stem-cell potential than cFF in terms of proliferation patterns, epigenetic modification and pluripotency, thus cAd-MSC could be more appropriate than cFF as donors of nuclei in somatic cell nuclear transfer for transgenesis. © 2012 Blackwell Publishing Ltd.
Park Y.,Gyeonggi Science High School |
Bae J.,Gyeonggi Science High School |
Lee J.W.,Ajou University
Transactions of the Korean Society of Mechanical Engineers, A | Year: 2015
A design method for a perforated panel is suggested to reduce the level of incident noise without obstructing the flow of incoming fluid. The key idea was to insert an array of 1/4 wavelength tubes around the holes of the perforate panel. First, various case studies were performed for a unit model with only one hole. In order to avoid any increase in the panel thickness, the unit model was vertically divided into three layers, and only the middle layer was used as the design domain. The number and array of 1/4 wavelength tubes connected to the hole were optimized to obtain the widest effective frequency range in the transmission loss curve as possible. Then, the optimally designed unit model was converted to a periodic array in the perforated panel to achieve the design goals. Even if the target frequency and the target transmission loss were set to 1000 Hz and 10 dB, respectively, the suggested design method for the a perforated panel could achieve noise reduction for various target values. © 2015 The Korean Society of Mechanical Engineers.
Eom K.,Ajou University |
Kim S.,Gyeonggi Science High School |
Lee D.,Gyeonggi Science High School |
Seo H.,Ajou University
RSC Advances | Year: 2015
This study reports the effect of oxide heterojunction solar cell (HSC) arrangement on the solar photocurrent spectra and the physical correlation to the interfacial band electronic structure. Based on the p-Cu2O/n-ZnO oxide junction, two types of stack arrangements were prepared to observe the solar photocurrent spectral change: FTO/Cu2O/ZnO/Al and FTO/ZnO/Cu2O/Al structures. In the photovoltaic cell structure, FTO was utilized as the p-type electrode, Cu2O as the p-type semiconductor, ZnO for the n-type semiconductor and Al as the n-type electrode. The HSC characteristics were characterized using ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy (XPS), diode current-voltage measurements, and finally, incident photon-to-current efficiency (IPCE). As a result, the IPCE spectra of the HSC were largely affected by (1) the bandgap of the first layer semiconductor, which is the first layer receiving incidence light regardless of the bandgap energy, and (2) the interfacial electronic band offset values in each stack. Therefore, this result offers a possible mechanism for why the HSC consisting of the FTO/Cu2O/ZnO stack shows better IPCE response than the FTO/ZnO/Cu2O stack in the view of electronic band-alignment. © 2015 The Royal Society of Chemistry.
Yoo H.-J.,Gyeonggi Science High School |
Chung O.-S.,Chungnam Development Institute |
Seo M.,Dankook University
Korean Journal of Parasitology | Year: 2012
Migratory birds have been suspected as playing a central role in transmission of various trematodes, but few surveys have been undertaken in the Republic of Korea. In the present study, we describe new fauna of microphallid flukes in Korea. Two species of microphallids were found in the intestines of 2 migratory bird species, namely the red necked stints (Calidris ruficollis) and the terek sandpiper (Xenus cinereus), in a coastal area of Gunsan-si, Jeollabuk-do. The microphallids recovered from the latter were 451 μm in length and 217 μm in width, and the eggs were very small, 13 μm by 8 μm. They had the characteristic extracecal vitellaria intruding into the median posttesticular area, belonging to Endocotyle incana. Another microphallids were discovered from both migratory birds, 417 μm in length and 249 μm in width. The cirrus was projecting into the genital atrium in form of male papilla, and bounded by a muscular flap, termed pseudogonotyl. They were identified as Spelotrema pseudogonotyla in consideration of the distinctive male papilla and pseudogonotyl. Besides these flukes, Maritrema obstipum and Gynaecotyla squatarolae also were recovered. This paper is in fact the first report on the presence of Spelotrema and Endocotyle in Korea. © 2012, Korean Society for Parasitology.
Lim J.H.,Gyeonggi Science High School |
Khang E.J.,Gyeonggi Science High School |
Lee T.H.,Gyeonggi Science High School |
Kim I.H.,Gyeonggi Science High School |
And 2 more authors.
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2013
We measured the electroencephalogram (EEG) of young students in the relaxed state and in the state of the mathematical activities. We applied the detrended fluctuation analysis and Kolmogorov-Sinai entropy (KSE) in the EEG signals. We found that the detrended fluctuation functions follow a power law with Hurst exponents larger than 1/2. The Hurst exponents enhanced at all EEG channels in the state of mathematical activities. The KSE in the relaxed state is larger than those in the state of the mathematical activities. These indicate that the entropy is enhanced in the disorder state of the brain. © 2013 Elsevier B.V.
Lee S.,Gyeonggi Science High School |
Kang M.,Gyeonggi Science High School |
Lee J.W.,Ajou University
Transactions of the Korean Society of Mechanical Engineers, A | Year: 2014
An optimal shape design algorithm is suggested to systematically design a traditional Korean musical instrument, the Pyeongyeong. The Pyeongyeong consists of 16 different chime stones called Gyeongpyeons. The first natural vibration frequency of each Gyeongpyeon must be adjusted to its target frequency, which is determined by the traditional sound tuning method. The second and third natural frequencies must be proportional to the first natural frequency with a specific ratio (1:1.498:2.378). The key idea in our suggested design algorithm is to use the sensitivity of natural frequencies to the variation in the length of each side of a Gyeongpyeon. The dimensions of five different Gyeongpyeons are determined by following the suggested algorithm. Changes in natural frequencies with respect to local thickness variation are closely investigated to compensate for errors that may occur during manufacturing. © 2013 The Korean Society of Mechanical Engineers.