• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.620-624
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• 2012

The role of moisture remaining inside the deposition chamber during the formation of the cubic boron nitride (c-BN) phase in BN film was investigated. BN films were deposited by an unbalanced magnetron sputtering (UBM) method. Single-crystal (001) Si wafers were used as substrates. A hexagonal boron nitride (h-BN) target was used as a sputter target which was connected to a 13.56 MHz radiofrequency electric power source at 400 W. The substrate was biased at -60 V using a 200 kHz high-frequency power supply. The deposition pressure was 0.27 Pa with a flow of Ar 18 sccm - $N_2$ 2 sccm mixed gas. The inside of the deposition chamber was maintained at a moisture level of 65% during the initial stage. The effects of the evacuation time, duration time of heating the substrate holder at $250^{\circ}C$ as well as the plasma treatment on the inside chamber wall on the formation of c-BN were studied. The effects of heating as well as the plasma treatment very effectively eliminated the moisture adsorbed on the chamber wall. A pre-deposition condition for the stable and repeatable deposition of c-BN is suggested.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.3
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• pp.210-218
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• 2021

Recently, pest-resistant living modified (LM) crops developed using RNA interference (RNAi) technology have been imported into South Korea. However, the potential adverse effects of unintentionally released RNAi-based LM crops on non-target species have not yet been reported. Coccinella septempunctata, which feeds on aphids, is an important natural enemy insect which can be exposed to the double-stranded RNA (dsRNA) produced by RNAi-based LM plants. To assess the risk of ingestion of Snf7 dsRNA by C. septempunctata, we first identified the species through morphological analysis of collected insects. A method for species identification at the gene level was developed using a specific C. septempunctata 12S rRNA. Furthermore, an experimental model was devised to assess the risk of Snf7 dsRNA ingestion in C. septempunctata. Snf7 dsRNA was mass-purified using an effective dsRNA synthesis method and its presence in C. septempunctata was confirmed after treatment with purified Snf7 dsRNA. Finally, the survival rate, development time, and dry weight of Snf7 dsRNA-treated C. septempunctata were compared with those of GFP and vATPase A dsRNA control treatments, and no risk was found. This study illustrates an effective Snf7 dsRNA synthesis method, as well as a high-concentration domestic insect risk assessment method which uses dsRNA to assess the risk of unintentional released of LM organisms against non-target species.

• Journal of the Korean Vacuum Society
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• v.18 no.2
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• pp.92-96
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• 2009

Nowadays, many research groups try to achieve the high Xe mole fraction discharge gas for high efficiency in AC-PDPs. However, the high Xe mole fraction discharge gas causes the high discharge voltage, which is a serious problem in AC-PDP's for high efficiency. In this study, the discharge gas with high Xe mole fraction and the low pressures has been applied and it's discharge voltage and vacuum ultraviolet emission characteristics have also been measured. It is shown that the discharge voltage is 354V and 389V at Ne+Xe (15%) with 400 Torr and Ne+Xe (30%) with 200 Torr, respectively. Their vacuum ultraviolet emission characteristics have similar characteristics to each other, in which their wavelengths are ranged from 140 nm to 200 nm. It is found in this experiment that the luminous efficiency for the discharge gas of Ne+Xe (30%) with 200 Torr is drastically increased by about 30%.

• Journal of Oral Medicine and Pain
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• v.24 no.3
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• pp.335-345
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• 1999

법의학적 개인식별 및 친생자 감정시 여러 개의 single tandem repeats(STR) 유전좌위 검색이 필요하다. 그 이유는 STR 유전좌위는 대립유전자 수가 적고 이형접합도가 낮아 서로 다른 개체간에도 동일한 유전좌위를 가질 확률이 높기 때문에 개인식별에 대한 기여도가 떨어지게 된다. 따라서 여러 개의 다양한 STR 유전좌위들을 동시에 분석함으로써 우연적으로 개체간에 유전자형이 일치할 가능성을 낮추어야 감정의 신뢰성을 높일 수 있으며 이에는 각 STR 유전좌위에 대한 유전좌위의 분포가 인종별, 지역별로 달라 이에 대한 유전자분포를 구하는 것이 선행조건이다. 이에 본 연구에서는 법의학적 개인식별 및 친자감정시 기초자료로 활용하기 위하여 서로 혈연관계가 없는 201명의 한국인 혈액에서 DNA를 추출하여 STR 유전좌위증 human coagulation factor XIII A subunit gene(F13A0l Locus), human c-fes/fps proto-oncogene(FESFPS Locus), human von Willebrand factor gene (vWA Locus)등 FFv Triplex 유전자를 중합효소반응에 의하여 동시에 증폭하고, 폴리아크릴아마이드겔을 이용한 전기영동 및 질산은 염색을 시행한 후 FFv Triplex유전자의 유전자형 및 대립유전자 빈도 등을 분석하여 다음과 같은 결과를 얻었다. (1) F13A01유전자는 5개의 대립유전자, 12개의 유전자형을 검출하였으며, 이형접합도는 60.7%로 나타났고 대립유전자 및 유전자빈도는 3.2, 4, 5, 6, 16 대립유전자에서 각각 0.34 3, 0.114, 0.062, 0.475, 0.005로 나타났으며, 대립유전자 7, 8, 9, 10, 11, 12, 13, 14, 15는 검출되지 않았다. (2) F13A01 대립유전자다양성 (allelic diversity value)은 0.641, 개인식별력(PD)은 0.814를 보였으며 대립유전자다양성 및 이형접합도가 다른 민족과 비교할 때 다소 낮았다. (3) FESFPS유전자는 8개 대립유전자 모두 나타났으며, 15개의 유전자형을 검출하였으며, 이형접합도는 66.7%로 나타났고 대립유전자 및 유전자빈도는 7, 8, 9, 10, 11, 11, 12, 13, 14 대립유전자에서 각각 0.002, 0.002, 0.005, 0.032, 0.507, 0.264, 0.197, 0.007로 나나났다. (4) FESFPS 대립유전자다양성(allelic diversity value)은 0.641, 개인식별력(PD)은 0.804를 보였다. (5) vWA유전자는 9개의 대립유전자, 23개의 유전자형을 검출하였으며, 이형접합도는 80.1%로 나타났고 대립유전자 및 유전자 빈도는 11, 12, 14, 15, 16, 17, 18, 19, 20 대립유전자 에서 각각 0.002, 0.002, 0.219, 0.032, 0.187, 0.279, 0.189, 0.072, 0.017로 나타났으며, 대립 유전자 13, 21는 검출되지 않았다. (6) vWA 대립유전자다양성(allelic diversity value)은 0.799, 개인식별력(PD)은 0.924로 매우 높게 나타냈다.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.31-36
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• 2001

The secondary election emission (SEE) yields for the thermally grown $SiO_2$ thin layers were measured by varying the thickness of the $SiO_2$ layer and the primary current. $SiO_2$ thin layers were thermally grown in a furnace at $930^{\circ}C$, whose thickness varied to be 5.8 nm, 19 nm, 43 nm, 79 nm, 95 nm, and 114 nm. When the $SiO_2$ layers were thinner than 43 nm, it was found that SEE curves followed the universal curve. However, for samples with a $SiO_2$ layer thicker than 79 nm, the SEE curves exhibited two maxima and the values of SEE yields were reduced. Additionally, as the current of primary electrons increased, the SEE yields were reduced. In this experiment, the maximum value of the SEE yield for $SiO_2$ layers was obtained to be 3.35 when the thickness of $SiO_2$ layer was 19 nm, with the primary electron energy 300 eV and the primary electron current 0.97 $\mu\textrm{A}$. The penetration and escape depth of an electron in the $SiO_2$ layers were calculated at the primary electron energy for the maximum value of the SEE yield and from these depths, it was calculated that the thickness of the $SiO_2$layer.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.543-553
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• 2011

Sea ice concentration calculated from the AMSR-E onboard Aqua satellite by using NASA Team2 sea ice algorithm has proven to be very accurate over sea ice in Antarctic Ocean. When glacial ice such as icebergs and ice shelves are dominant in an AMSR-E footprint, the accuracy of the ice concentration calculated from NASA Team2 algorithm is not well maintained due to the different microwave characteristics of the glacial ice from sea ice. We extracted the concentrations of sea ice and glacial ice from two ENVISAT ASAR images of George V coast in southern Antarctica, and compared them with NASA Team2 sea ice concentration. The result showed that the NASA Team2 algorithm underestimates the concentration of glacial ice. To interpret the large deviation of estimation over glacial ice, we analyzed the characteristics of microwave radiation of the glacial ice in PR(polarization ratio), GR(spectral gradient ratio), $PR_R$(rotated PR), and ${\Delta}GR$ domain. We found that glacial ice occupies a unique region in the PR, GR, $PR_R$, and ${\Delta}GR$ domain different from other types of ice such as ice type A, B, and C, and open water. This implies that glacial ice can be added as a new category of ice to the AMSR-E NASA Team2 sea ice algorithm.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.223-228
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• 2013

Phytoplasmas were detected consistently in 42 mulberry cultivars showing dwarf disease using DNA analysis by amplification with phytoplasma universal primer pairs P1/P7 (about 1.8 kb and R16F2n/R2 (about 1.2 kb). The point mutation from 42 cultivars of mulberry tree was detected by single-strand conformation polymorphism (SSCP) analysis. The SSCP profiles were clearly observed from all of cultivars in 8% polyacrylamide gel, electrophoresizing for and running 8-15 hrs. at 150V, $10^{\circ}C$. The MD and JWB phytoplasma PCR products was mixed and electrophoresis was performed to detect their polymorphism. In this results, the SSCP profiles of all bands of MD and JWB were analyzed on single lane and were distinct in their each of band patterns. The SSCP analysis was possible to detect of 1.8 kb and 1.2 kb nucleotide size and near close band patterns were distinct by mix of two samples. Previously, it was only possible to detect of point mutation under 600 bp nucleotide sequence by SSCP analysis but this modification of SSCP technique was possible to detect clearly SSCP band patterns of about 1.8 kb and 1.2 kb nucleotides.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.4
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• pp.121-127
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• 2022

β-Gallium oxide (Ga₂O₃), an ultra-wide bandgap semiconductor, has attracted great attention due to its promising applications for high voltage power devices. The most stable phase among five different polytypes, β-Ga₂O₃ has the wider bandgap of 4.9 eV and higher breakdown electric field of 8 MV/cm. Furthermore, it can be grown from melt source, implying higher growth rate and lower fabrication cost than other wide bandgap semiconductors such as SiC, GaN and diamond for the power device applications. In this study, β-Ga₂O₃ bulk crystals were grown by the edge-defined film-fed growth (EFG) process. The growth direction and the principal surface were set to be the [010] direction and the (100) plane of the β-Ga₂O₃ crystal, respectively. The spectra measured by Raman an alysis could exhibit the crystal phase an d impurity dopin g in the β-Ga₂O₃ ingot, and the crystallinity quality and crystal direction were analyzed using high-resolution X-ray diffraction (HRXRD). The crystal quality and various properties of as-grown β-Ga₂O₃ ribbon was systematically analyzed in order to investigate the spatial variation in entire crystal grown by EFG method.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.1
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• pp.21-25
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• 2004

From the gradual increasing state of charge (GISOC) observations, electrochemical behavior of multi-walled carbon nanotube│(lM LiP $F_{6}$ , EC,DEC,DME 3:5:5 volume ratio)│lithium cells was evaluated using the galvanostatic charge-discharge process. A MWCNT delivers a specific charge capacity of 1,300 mAh/g in a Li cell when cycled up to an end voltage of 0 V (vs. Li/L $i^{＋}$ )at a constant current rate every 10 hours. However, in the present study, the specific discharge capacity obtained is 338 mAh/g, thus amounting to a coulombic efficiency of only 26％. Further, when the MWCNT│Li cells were tested using the GISOC method, two distinguishable linear-fit ranges were observed due to the intercalation/deintercalation of lithium, which were found to have II $E_1$, IIC $s_1$ and II $E_2$of 27.3％, 372 mAh/g, and 25.5％, respectively. Q $c_1$, could be calculated from the data of IIE and IICs of each range by the modified equation "II $C_{sum}$= $\Sigma$( $Q_{C}$- $Q_{D}$)=(II $E_{1}$$^{-1}$ ) $Q_{Dl}$ ＋(II $E_2$$^{-1}$ -1) ( $Q_{D2}$- $Q_{Dl}$ ) ＋ IIC $s_1$= $Q_{Cl}$ - $Q_{Dl}$ ". Results of the GISOC method could be converted to the results of galvanostatic charge-discharge process, irrespective of the state of charge of the cell or battery.ery.y.y.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2266-2270
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• 2007

Electron transfer of a redox protein at a bare gold electrode is too slow to observe the redox peaks. A novel Nafion-riboflavin functional membrane was constructed during this study and electron transfer of cytochrome c, superoxide dismutase, and hemoglobin were carried out on the functional membrane-modified gold electrode with good stability and repeatability. The immobilized protein-modified electrodes showed quasireversible electrochemical redox behaviors with formal potentials of 0.150, 0.175, and 0.202 V versus Ag/AgCl for the cytochrome c, superoxide dismutase and hemoglobin, respectively. Whole experiment was carried out in the 50 mM MOPS buffer solution with pH 6.0 at 25 oC. For the immobilized protein, the cathodic transfer coefficients were 0.67, 0.68 and 0.67 and electron transfer-rate constants were evaluated to be 2.25, 2.23 and 2.5 s?1, respectively. Hydrogen peroxide concentration was measured by the peroxidase activity of hemoglobin and our experiment revealed that the enzyme was fully functional while immobilized on the Nafion-riboflavin membrane.