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Electrical and Structural Properties of $CuInS_2$ thin films fabricated by EBE(Electronic Beam Evaporator) Method (전자빔 증착기로 증착된 $CuInS_2$ 박막의 전기적 구조적 특성)

  • Yang, Hyeon-Hun;Kim, Young-Jun;Jeong, Woon-Jo;Park, Gye-Choon
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.170-173
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    • 2006
  • [ $CuInS_2$ ] filims were appeared from 0.84 to 1.27 of Cu/In composition ratio and sulfur composition ratios of $CuInS_2$ thin films fabricated, Also when Cu/In composition ratio was 1.03, $CuInS_2$ thin film with chalcopyrite structure had the highest XRD peak (112). And lattice constant (a) of and grain size of the film tin s ambient were appeared a little larger than those in only Vacuum The films in S ambient were p-type with resistive of around $10^{-1}{\Omega}cm$ and optical energy band gaps of the films in S ambient were appeared a little larger than those in only Vacuum. Analysis of the optical energy band gap of $CuInS_2$ thin films a value of 1.53eV.

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Seasonal and Spatial Variations of Nutrient Fluxes in the Intertidal Flat of Keunso Bay, the Yellow Sea (서해 근소만 갯벌에서 영양염 플럭스의 계절 변화)

  • Kim, Kyung-Hee;Kim, Dong-Seon
    • Ocean and Polar Research
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    • v.30 no.3
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    • pp.225-238
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    • 2008
  • In order to investigate the effects of intertidal sediments on the nutrient cycle in coastal environments, the benthic fluxes of ammonium, nitrate, nitrite, phosphate, and silicate at two stations on the intertidal flat of Keunso Bay were determined during each season. The efflux of ammonium was observed at S1 and resulted from the diffusion of remineralized ammonium and acceleration caused by the bioirrigation of macrofauna. The influx of ammonium at S2 was probably due to nitrification in the water column. The influx of nitrate was observed at both stations during all seasons, indicating that the nitrate in the pore water was removed by denitrification. Vigorous bioirrigation led to the efflux of dissolved inorganic nitrogen (DIN) at S1, whereas the influx of DIN at S2 was predominantly caused by denitrification. Contrary to the diffusive and bio-irrigated release of remineralized phosphate from the sediment at S1, the influx of phosphate was observed at S2, which may be attributable to adsorption onto iron oxides in the aerobic sediment layer. Silicate, which is produced by the dissolution of siliceous material, was mostly released from the sediment by molecular diffusion and bioirrigation. However, the influx of silicate was observed at S2 during spring and winter, which was ascribed to adsorption by particulate matter or assimilation by benthic microphytes. The annual fluxes of DIN were 328 mmol $m^{-2}yr^{-1}$ at S1 and -435 mmol $m^{-2}yr^{-1}$ at S2. The annual fluxes of phosphate were negative at both sites (-2.8 mmol $m^{-2}yr^{-1}$ at S1 and -28.9 mmol $m^{-2}yr^{-1}$ at S2), whereas the annual fluxes of silicate were positive at both sites (843 mmol $m^{-2}yr^{-1}$ at S1 and 243 mmol $m^{-2}yr^{-1}$ at S2).

ON CYCLIC DECOMPOSITIONS OF THE COMPLETE GRAPH INTO THE 2-REGULAR GRAPHS

  • Liang, Zhihe
    • Journal of applied mathematics & informatics
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    • v.24 no.1_2
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    • pp.261-271
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    • 2007
  • The symbol C($m_1^{n_1}m_2^{n_2}{\cdots}m_s^{n_s}$) denotes a 2-regular graph consisting of $n_i$ cycles of length $m_i,\;i=1,\;2,\;{\cdots},\;s$. In this paper, we give some construction methods of cyclic($K_v$, G)-designs, and prove that there exists a cyclic($K_v$, G)-design when $G=C((4m_1)^{n_1}(4m_2)^{n_2}{\cdots}(4m_s)^{n_s}\;and\;v{\equiv}1(mod\;2|G|)$.

NDRG2 Controls COX-2/PGE2-Mediated Breast Cancer Cell Migration and Invasion

  • Kim, Myung-Jin;Kim, Hak-Su;Lee, Soo-Hwan;Yang, Young;Lee, Myeong-Sok;Lim, Jong-Seok
    • Molecules and Cells
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    • v.37 no.10
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    • pp.759-765
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    • 2014
  • N-myc downstream-regulated gene 2 (NDRG2), which is known to have tumor suppressor functions, is frequently down-regulated in breast cancers and potentially involved in preventing the migration and invasion of malignant tumor cells. In the present study, we examined the inhibitory effects of NDRG2 overexpression, specifically focusing on the role of cyclooxygenase-2 (COX-2) in the migration of breast cancer cells. NDRG2 overexpression in MDA-MB-231 cells inhibited the expression of the COX-2 mRNA and protein, the transcriptional activity of COX-2, and prostaglandin $E_2$ ($PGE_2$) production, which were induced by a treatment with phorbol-12-myristate-13-acetate (PMA). Nuclear transcription factor-${\kappa}B$ (NF-${\kappa}B$) signaling attenuated by NDRG2 expression resulted in a decrease in PMA-induced COX-2 expression. Interestingly, the inhibition of COX-2 strongly suppressed PMA-stimulated migration and invasion in MDA-MB-231-NDRG2 cells. Moreover, siRNA-mediated knockdown of NDRG2 in MCF7 cells increased the COX-2 mRNA and protein expression levels and the PMA-induced COX-2 expression levels. Consistent with these results, the migration and invasion of MCF7 cells treated with NDRG2 siRNA were significantly enhanced following treatment with PMA. Taken together, our data show that the inhibition of NF-${\kappa}B$ signaling by NDRG2 expression is able to suppress cell migration and invasion through the down-regulation of COX-2 expression.

Design of Lightweight S-Box for Low Power AES Cryptosystem (저전력 AES 암호시스템을 위한 경량의 S-Box 설계)

  • Lee, Sang-Hong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.1
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    • pp.1-6
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    • 2022
  • In this paper, the design of lightweight S-Box structure for implementing a low power AES cryptosystem based on composite field. In this approach, the S-Box is designed as a simple structure by which the three modules of x2, λ, and GF((22)2) merge into one module for improving the usable area and processing speed on GF(((22)2)2). The designed AES S-Box is modelled in Veilog-HDL at structural level, and a logic synthesis is also performed through the use of Xilinx ISE 14.7 tool, where Spartan 3s1500l is used as a target FPGA device. It is shown that the designed S-Box is correctly operated through simulation result, where ModelSim 10.3. is used for performing timing simulation.

Cross-Correlation Distribution of a p-ary m-Sequence Family Constructed by Decimation (Decimation에 의해 생성된 p-진 m-시퀀스 군의 상호 상관 값의 분포)

  • Seo, Eun-Young;Kim, Young-Sik;No, Jong-Seon;Shin, Dong-Joon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.9C
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    • pp.669-675
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    • 2008
  • For an odd prime p, n=4k and $d=((p^2k+1)/2)^2$, there are $(p^{2k}+1)/2$ distinct decimated sequences, s(dt+1), $0{\leq}l<(p^{2k}+1)/2$, of a p-ary m-sequence, s(t) of period $p^n-1$. In this paper, it is shown that the cross-correlation function between s(t) and s(dt+l) takes the values in $\{-1,-1{\pm}\sqrt{p^n},-1+2\sqrt{p^n}\}$ and their, cross-correlation distribution is also derived.

Optical Properties of Undoped and Co2+ Doped CaGa2(S,Se)4 and Caln2(S,Se)4 Single Crystals ($CaGa_{2}(S,Se)_{4}:Co^{2+}$$Caln_{2}(S,Se)_{4}:Co^{2+}$ 단결정의 광학적 특성)

  • Kim, Hyung-Gon;Kim, Nam-Oh;Kim, Duck-Tae;Hyun, Seung-Cheol;Bang, Tae-Hwan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11b
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    • pp.43-48
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    • 2004
  • Undoped and $Co^{2+}$-doped $CaGa_2S_4$, $CaGa_2Se_4$, $CaIn_2S_4$. and $CaIn_2Se_4$ single crystals were grown by using the chemical transport reaction method The temperature dependence of the optical energy gap was well fitted by the Varshni equation. In the Co2+ - doped $CaGa_2S_4$, $CaGa_2Se_4$, $CaIn_2S_4$, and $CaIn_2Se_4$ single crystals, two groups of impurity optical absorption peaks due to Co2+ sited in a Td symmetry were observed in the wavelength regions of 600 900 nm and 1350 1950 nm at 11 K.耀

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The Effect of Habitat Size on Huanren Brown Frog (Rana huanrensis) Larvae's Growth Rate in Mt. Surak (수락산에 서식하는 계곡산개구리(Rana huanrensis Fei, Ye & Huang, 1991) 유생의 서식지 면적에 따른 생장률 연구)

  • Na, Sumi;Um, Yewon;Kim, Hyun-jung;An, Chi-Kyung;Yi, Hoonbok
    • Ecology and Resilient Infrastructure
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    • v.4 no.2
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    • pp.75-82
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    • 2017
  • This study was executed to know the effect of the habitat size on huanren brown frog (Rana huanrensis) larvae's growth. We've conducted the study on Mt. Surak in Sanggye-dong, Nowon-gu, Seoul. Our study site was discriminated the huanren brown frog larvae's habitat into the three different areas, such as small area (S1, $3.91m^2$), middle area (S2, $4.42m^2$), and large area (S3, $38.37m^2$) in the same water channel. We measured two times per a week the 15 huanren brown frog larvae's body length, and developmental stages (foreleg, hind leg, tail length) including the environmental factors (humidity, air temperature and water temperature) of the study site from March 30 to June 28 in 2016. The only hatching rate was measured for the three egg sacs at the S2 study site. We found that the average hatching rate was $76.84{\pm}18.23(%)$ at S2. Generally, because of less precipitation during our study periods, all habitat areas for our study site were gradually decreased. The middle area, S2, was not reduced, the small area, S1, was reduced more than a fourth, and the largest area, S3, was drastically reduced more than half from initial area. There was no statistically difference among the three study sites for the three environmental factors (average humidity, average air temperature, and average water temperature) by F-test, but there were significant difference among the three site for the larvae's body length (F-test p< 0.05). Therefore, the larger of habitat areas, the larger of the larvae length as well as the faster of the larvae's developmental stages. When we measured the body lengths of immature huanren brown frogs, the immature frog of S1 was smallest, the immature frog of S3 was middle lenght, and the immature frog of S2 was largest. There were statistically different among the three study sites for the immature huanren brown frogs (F-test, p< 0.05). Because the S2 study site was relatively stable without rarely changing the study area, it meant that huanren brown frog was sensitive to habitat areas. Based on the results of this study, if we study on the effect of the altitude on the growth rate of huanren brown frog, it must be helpful in understanding the habitat environment of the population of huanren brown frog.

First-principles Calculations on Magnetism of 1H/1T Boundary in Monolayer MoS2 (제일원리계산에 의한 단층 MoS2의 1H/1T 경계 자성)

  • Jekal, Soyoung;Hong, Soon Cheol
    • Journal of the Korean Magnetics Society
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    • v.26 no.3
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    • pp.71-75
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    • 2016
  • Monolayer $MoS_2$ is energetically most stable when it has a 1H phase, but 1H to 1T phase transition ($1H{\rightarrow}1T$) is easily realized by various ways. Even though magnetic moment is not observed during $1H{\rightarrow}1T$, $0.049{\mu}_B/MoS_2$ is obtained in local 1T phase; 75% 2H and 25% 1T phases are mixed in ($2{\times}2$) supercell. Most magnetic moment is originated from the 1T phase Mo atom in the supercell, while the magnetic moments of other atoms are negligible. As a result, magnetic/non-magnetic boundary is created in the monolayered $MoS_2$. Our result suggests that $MoS_2$ can be applied for spintronics such as a spin transistor.

Optical Characteristics of ZnS/CaF2/ZnS/Cu with Different Optical Thickness of CaF2 Layer (CaF2 두께 변화에 따른 ZnS/CaF2/ZnS/Cu 다층 박막의 광특성)

  • Kim, Jun-Sik;Jang, Gun-Eik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.7
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    • pp.584-588
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    • 2009
  • Layered ZnS/$CaF_2$/ZnS/Cu film was deposited on glass substrate by using evaporation method. ZnS and $CaF_2$ were chosen as high and low refractive materials. Cu was used as mid-reflective layer. Reflectance with different optical thickness of $CaF_2$ ranging from $0.25{\lambda}\;to\;0.5{\lambda}$ were systematically investigated by using spectrophotometer. In order to expect the experimental results, the simulation program, the Essential Macleod Program(EMP) was adopted and compared with the experimental data. Based on the results taken by spectrophotometer, the ZnS/$CaF_2$/ZnS/Cu multi-layered thin film show the maximum reflectance of 80% at 625nm $(0.25{\lambda}\;in\;CaF_2)$ and 42% at 660nm $(0.5{\lambda}\;in\;CaF_2)$ respectively. As compared with the experimental results and simulation data, it was confirmed the experimental data is well matched with the EMP data.