• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.176-183
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• 2000

In this paper, sixth order hannonic injected PWM for improving‘ input CWTent distortion of single switch t three phase boost converter is presented. Peliodic sixth order hmmonic ${\gamma}$oltage is inj<:ded in the control circuit t to var${\gamma}$ the duty ratio of the converter switch within one switching cycle. In the result, the input phase c currents are forced to track the input voltage and an 해most unity power factor is obtained. Expelimental r results are verified by converter operating at 400V /6kW with three phase 140V ~220V input and by C02 arc w welding machine which was nonlinear load with 3 $\phi$ 220V input.

• Microbiology and Biotechnology Letters
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• v.28 no.2
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• pp.80-86
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• 2000

To develop thermotolerant ethanol producing yeast strains, the protoplasts of Saccharomyces carlsbergensis having good fermentability at $30^{\circ}C$ and Kluyveromyces marxianus able to grow at $42^{\circ}C$ were fused. Under the optimal conditions for protoplast formation, the frequency of protoplast formation of S. carlsbergensis was 92 - 94% and that of K. marxianus was 98%. Fusion frequency between S. carlsbergensis and K. marxianus was $1.4\times10^{-6}-4.8$\times10^{-7}$. Among the 27 fusants obtained, 6 fusants were able to grow at $42^{\circ}C$. While the parental strains produced 3.2-3.4%(w/v) ethanol after 3 days from the fermentation medium containing glucose, fusants SK41-4 and SK53-22 produced 5.2%(w/v) ethanol in the same condition. The thermotolerance of SK53-22 was not high, but that of SK41-4 was quite high.

• Journal of Species Research
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• v.2 no.2
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• pp.191-202
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• 2013

The article provides information on type specimens of 150 taxa of vascular plants from Korea, kept in the Herbarium of the Komarov Botanical Institute of the Russian Academy of Sciences. For all specimens, type category is indicated. Lectotypes for the names of Clematis brachyura Maxim., C. spectabilis Palib., Corydalis wilfordii Regel, Poa viridula Palib., Polygonum marretii H. L$\acute{e}$v., P. sagittatum L. var. hallaisanense H. L$\acute{e}$v., P. taquetii H. L$\acute{e}$v. and P. thunbergii Sieb. et Zucc. var. coreana H. L$\acute{e}$v. were designated. Type specimens examined in this article belong to the taxa described by Russian botanists V.L. Komarov, K.J. Maximovicz and I.V. Palibin, French botanist A.A.H. L$\acute{e}$veill$\acute{e}$ (some with co-author E. Vaniot) and others.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1351-1352
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• 2007

$ZrO_2$ 와 $HfO_2$ 박막에 이온 주입을 거친 후 열처리 과정을 통해 Ge 나노입자를 형성시켜 MOS 커패시터를 제작하였다. C-V 곡선에서는 반시계 방향의 hysteresis가 관찰되었으며, $ZrO_2$ MOS 커패시터에서는 -9 V에서 9 V까지 전압변화를 주었을 때 3 V 정도의 메모리 윈도우가 나타남을 확인 할 수 있었다. 또한, $HfO_2$ MOS 커패시터에서는 -10 V에서 10 V까지 전압변화를 주었을 때 3.45 V의 메모리 윈도우를 관찰 할 수 있었다.

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.409-414
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• 1986

The reduction of $VO_2^+$ ion by ethanol in sulfuric acid leads to the formation of vanadyl sulfate. Spectrophotometric measurements on the solution containing products, vanadyl sulfate, are also reported. Kinetic studies on reduction of $VO_2^+$ by ethanol have been carried out at 35${\circ}C$ and 50${\circ}C$. The reaction mechanism for reduction of $VO_2^+$ is discussed.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.165-168
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• 2002

TLC(Thin Layer Chromatography) 는 제약산업이나 생화학 연구 그리고 여러 산업 현장에서 널리 이용되는 화학 분석 방법이다 . 본 연구에서는 적은 비용으로도 많은 양의 시료를 신속하게 분리할 수 있는 TLC를 이용하여 유기산인 젖산 (Lactic acid) 을 분리는 전개방법을 개발하였다 . 전개용매는 2 가지 용매 (1) nitroethane nitromethane : ethanol: water: I-propanol = 1 : 2 : 3 : 4 : 5 (v/v/v/v/v), (2) diisopropyl ether. formic acid. water = 90 : 7 : 3 (v/v/v) 를 사용하였다 . 발색시약은 A : bromocresol purple reagent I, B . bromocresol purple reagent II, C : bromocresol green-bromophenol blue-potassium permanganate reagent 를 사용하여 분석하는 방법을 개발하였다 $^6)$. 젖산의 분리는 silica gel TLC plate를 이용하는 경우 , 용매 (1) 에 발색시약 B를 사용했을 때 , 분리 확인이 가장 좋았다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.94-98
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• 2000

Polycrystalline SBTN ferroelectric thin films were prepared by sol-gel method with various Nb mole ratios on Pt/ $SiO_2$/Si (100) substrates. The films were annealed at different temperatures and characterized in terms of phase and microstructure. Relatively a well saturated hysteresis pattern was obtained at x =0.2 in S $r_{0.8}$B $i_{2.3}$(T $a_{1-x}$ N $b_{x}$)$_2$ $O_{9+}$$\alpha$/ thin films. At an applied voltage of 5V, the dielectric constant ($\varepsilon$$_{r}$) and dissipation factor (tan $\delta$) of typical S $r_{0.8}$B $i_{2.3}$(T $a_{1-x}$ N $b_{x}$)$_2$ $O_{9+}$$\alpha$/ thin film (x=0.2) were about 236.2 and 0.034. Measured remanent polarization (2Pr) and coercive field (Ec) were 4.28C/c $m_2$, and 38.88kv/cm respectively. No fatigue was observed up to 6$\times$10$_{10}$ switching cycles at 5V and the normalized polarization reduced by a factor of only 4%.%. 4%.%. 4%.%.%.%.%.

• Communications of the Korean Mathematical Society
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• v.32 no.2
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• pp.435-445
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• 2017

Let D be a directed graph with p vertices and q arcs. A vertex out-magic total labeling is a bijection f from $V(D){\cup}A(D){\rightarrow}\{1,2,{\ldots},p+q\}$ with the property that for every $v{\in}V(D)$, $f(v)+\sum_{u{\in}O(v)}f((v,u))=k$, for some constant k. Such a labeling is called a V-super vertex out-magic total labeling (V-SVOMT labeling) if $f(V(D))=\{1,2,3,{\ldots},p\}$. A digraph D is called a V-super vertex out-magic total digraph (V-SVOMT digraph) if D admits a V-SVOMT labeling. In this paper, we provide a method to find the most vital nodes in a network by introducing the above labeling and we study the basic properties of such labelings for digraphs. In particular, we completely solve the problem of finding V-SVOMT labeling of generalized de Bruijn digraphs which are used in the interconnection network topologies.

• Korean Journal of Materials Research
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• v.29 no.8
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• pp.463-468
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• 2019

The electrical and interfacial properties of $HfO_2/Al_2O_3$ and $Al_2O_3/HfO_2$ dielectrics on AlN/p-Ge interface prepared by thermal atomic layer deposition are investigated by capacitance-voltage(C-V) and current-voltage(I-V) measurements. In the C-V measurements, humps related to mid-gap states are observed when the ac frequency is below 100 kHz, revealing lower mid-gap states for the $HfO_2/Al_2O_3$ sample. Higher frequency dispersion in the inversion region is observed for the $Al_2O_3/HfO_2$ sample, indicating the presence of slow interface states A higher interface trap density calculated from the high-low frequency method is observed for the $Al_2O_3/HfO_2$ sample. The parallel conductance method, applied to the accumulation region, shows border traps at 0.3~0.32 eV for the $Al_2O_3/HfO_2$ sample, which are not observed for the $Al_2O_3/HfO_2$ sample. I-V measurements show a reduction of leakage current of about three orders of magnitude for the $HfO_2/Al_2O_3$ sample. Using the Fowler-Nordheim emission, the barrier height is calculated and found to be about 1.08 eV for the $HfO_2/Al_2O_3$ sample. Based on these results, it is suggested that $HfO_2/Al_2O_3$ is a better dielectric stack than $Al_2O_3/HfO_2$ on AlN/p-Ge interface.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.156-156
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• 2003

수평 전기로에서 ZnIn$_2$S$_4$ 다결정을 합성하여 HWE(Hot Wall Epitaxy)방법으로 2nIn2S4단결정 박막을 반절연성 GaAs(100)기판 위에 성장시켰다. ZnIn2S4 단결정 박막은 증발원의 온도를 610 $^{\circ}C$, 기판의 온도를 450 $^{\circ}C$로 성장시켰고 성장 속도는 0.5 $\mu\textrm{m}$/hr로 확인되었다. ZrIn2S4 단결정 박막의 결정성의 조사에서 10 K에서 광발광(photoluminescence) 스펙트럼이 433 nm (2.8633eV)에서 exciton emission스펙트럼이 가장 강하게 나타났으며, 또한 이중결정 X-선 요동곡선(DCRC)의 반폭치(FWHM)도 133 arcsec로 가장 작아 최적 성장 조건임을 알 수 있었다. Hall 효과는 van der Pauw방법에 의해 측정되었으며, 온도에 의존하는 운반자 농도와 이동도는 293K에서 각각 8.51$\times$$10^{17}$ electron/$cm^{-3}$ 291 $\textrm{cm}^2$/v-s였다. ZnIn2S4 단결정 박막의 광전류 단파장대 봉우리들로부터 10 K에서 측정된 $\Delta$Cr(crystal field splitting)은 0.1678 eV, $\Delta$So(spin orbit coupling)는 0.0148 eV였다. 10 K의 광발광 측정으로부터 고품질의 결정에서 볼 수 있는 free exciton 과 매우 강한 세기의 중성 주개 bound exciton등의 피크가 관찰되었다. 이때 중성 주개 bound exciton의 반치폭과 결합 에너지는 각각 9 meV와 26 meV 였다. 또한 Haynes rule에 의해 구한 불순물의 활성화 에너지는 130 meV 였다.다.