• Title/Summary/Keyword: research and development

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Effects of Heterostructure Electrodes on the Reliability of Ferroelectric PZT Thin Films

  • Kim, Seung-Hyun;Woo, Hyun-Jung;Koo, Chang-Young;Yang, Jeong-Seung;Ha, Su-Min;Park, Dong-Yeon;Lee, Dong-Su;Ha, Jo-Woong
    • Journal of the Korean Ceramic Society
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    • v.39 no.4
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    • pp.341-345
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    • 2002
  • The effect of the Pt electrode and the $Pt-IrO_2$ hybrid electrode on the performance of ferroelectric device was investigated. The modified Pt thin films with non-columnar structure significantly reduced the oxidation of TiN diffusion barrier layer, which rendered it possible to incorporate the simple stacked structure of Pt/TiN/poly-Si plug. When a $Pt-IrO_2$ hybrid electrode is applied, PZT thin film properties are influenced by the thickness and the partial coverage of the electrode layers. The optimized $Pt-IrO_2$ hybrid electrode significantly enhanced the fatigue properties with minimal leakage current.

Synthesis of Methyl-substituted Bicyclic Carbanucleoside Analogs as Potential Antiherpetic Agents

  • Kim, Kyung-Ran;Park, Ah-Young;Lee, Hyung-Rock;Kang, Jin-Ah;Kim, Won-Hee;Chun, Pu-Soon;Bae, Jang-Ho;Jeong, Lak-Shin;Moon, Hyung-Ryong
    • Bulletin of the Korean Chemical Society
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    • v.29 no.10
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    • pp.1977-1982
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    • 2008
  • Novel bicyclo[3.1.0]hexanyl purine nucleoside analogues were synthesized as potential antiherpetic agents via a bicyclo[3.1.0]hexanol (${\pm}$)-8, which was prepared using a highly efficient carbenoid cycloaddition reaction. A highly diastereoselective reduction of ketone and a Mitsunobu reaction for the condensation of glycosyl donor (${\pm}$)-12 with 6-chloropurine were employed.

Breakthrough behaviour of NBC canister against carbon tetrachloride: a simulant for chemical warfare agents

  • Srivastava, Avanish Kumar;Shah, D.;Mahato, T.H.;Singh, Beer;Saxena, A.;Verma, A.K.;Shrivastava, S.;Roy, A.;Yadav, S.S.;Shrivastava, A.R.
    • Carbon letters
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    • v.13 no.2
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    • pp.109-114
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    • 2012
  • A nuclear, biological, chemical (NBC) canister was indigenously developed using active carbon impregnated with ammoniacal salts of copper (II), chromium (VI) and silver (I), and high efficiency particulate aerosol filter media. The NBC canister was evaluated against carbon tetra chloride ($CCl_4$) vapours, which were used as a simulant for persistent chemical warfare agents under dynamic conditions for testing breakthrough times of canisters of gas masks in the National Approval Test of Respirators. The effects of $CCl_4$ concentration, test flow rate, temperature, and relative humidity (RH) on the breakthrough time of the NBC canister against $CCl_4$ vapour were also studied. The impregnated carbon that filled the NBC canister was characterized for surface area and pore volume by $N_2$ adsorption-desorption isotherm at liquid nitrogen temperature. The study clearly indicated that the NBC canister provides adequate protection against $CCl_4$ vapours. The breakthrough time decreased with the increase of the $CCl_4$ concentration and flow rate. The variation in temperature and RH did not significantly affect the breakthrough behaviour of the NBC canister at high vapour concentration of $CCl_4$, whereas the breakthrough time of the NBC canister was reduced by an increase of RH at low $CCl_4$ vapour concentration.

Two New Records of Crangonid Shrimps (Crustacea: Decapoda: Caridea) in Korean Waters

  • Kim, Jung-Nyun;Choi, Jung-Hwa;Choi, Kwang-Ho;Kim, Sung-Tae;Chang, Dae-Soo
    • Animal Systematics, Evolution and Diversity
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    • v.24 no.3
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    • pp.265-268
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    • 2008
  • Two crangonid shrimps, Paracrangon abei Kubo, 1937 and Pontocaris sibogae (De Man, 1918), collected from the northeastern and southeastern waters of Jeju Island, are newly recorded into the Korean fauna. The former is the second species and the latter is the only species of each genus recorded in Korea. Morphological and distributional accounts of these two species are briefly discussed.

Two Penaeoid Shrimp (Crustacea: Decapoda) New to Korean Waters

  • Kim, Jung-Nyun;Choi, Jung-Hwa;Choi, Kwang-Ho;Kim, Sung-Tae;Choi, Young-Min
    • Fisheries and Aquatic Sciences
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    • v.10 no.4
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    • pp.200-204
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    • 2007
  • We describe two penaeoid shrimp, Hymenopenaeus equalis and Metapenaeus ensis, that were collected from an area northwest of Jeju Island and are new to Korean waters. Hymenopenaeus equalis is the first Korean representative of this genus. A brief distributional and morphological description of the two species is provided.

Cloning and Expression of Escherichia coli K13 Phytase Gene (appA13) Isolated from Seawater

  • Kim Young-Ok;Kim Han-Woo;Lee Jung-Ho;Kim Kyung-Kil;Lee Jong-Yun
    • Fisheries and Aquatic Sciences
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    • v.6 no.1
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    • pp.20-26
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    • 2003
  • A bacterial strain was isolated from seawater to screen for phytase activities. A colony had the highest activity and was identified as an Escherichia coli strain. Using primers derived from E. coli acid phosphatase appA sequence, we cloned a 1,495 bp DNA fragment connected with the pGEM-T vector. It was over-expressed under lac promoter combined with its native promoter in E. coli $DH5\alpha$. The expression of the phytase gene occurred during late exponential growth and the intracellular phytase production was 16.9 units/ml. The yield of recombinant phytate was 412-fold higher than that of wild type E. coli K13.

Detection of Fish Killing Dinoflagellates Cochlodinium polykrikoides and Karlodinium veneficum (Dinophyceae) in the East China Sea by Real-time PCR

  • Park, Tae-Gyu;Kang, Yang-Soon;Park, Young-Tae;Bae, Heon-Meen;Lee, Yoon
    • ALGAE
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    • v.24 no.2
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    • pp.105-110
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    • 2009
  • The rDNAs of figh-killing dinoflagellates Cochlodinium polykrikoides and Karlodinium veneficum were detected from the East China Sea by species-specific real-time PCR probes. Sequence analysesusing the partial ITS sequences from the real-time PCR products showed identical sequences with C. Polykrikoides and K. veneficum, respectively and low expectation values (E-value) of less than 1e-5 suggesting the presence of these organisms in the East Ching Sea shelf water that flows into the Tsushima Strait and the Yellow Sea.