• Title/Summary/Keyword: $^{211}At$

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H-induced Magnetism at Stepped Si (100) Surface

  • Lee, Jun-Ho;Cho, Jun-Hyung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.211-211
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    • 2012
  • Using spin-polarized density-functional theory calculations, we find that the existence of either Peierls instability or antiferromagnetic spin ordering is sensitive to hydrogen passivation near the step. As hydrogens are covered on the terrace, the dangling bond electrons are localized at the step, leading to step-induced states. We investigate the competition between charge and spin orderings in dangling-bond (DB) wires of increasing lengths fabricated on an H-terminated vicinal Si(001) surface. We find antiferromagnetic (AF) ordering to be energetically much more favorable than charge ordering. The energy preference of AF ordering shrinks in an oscillatory way as the wire length increases. This oscillatory behavior can be interpreted in terms of quantum size effects as the DB electrons fill discrete quantum levels.

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Microbial Inhibition Test of Sustained-Release Chlorine Dioxide Gas Freshness Retaining Agent

  • Choe, Yoowha
    • International Journal of Advanced Culture Technology
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    • v.8 no.3
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    • pp.211-215
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    • 2020
  • Currently, most of the chlorine dioxide gas is processed at the beginning of storage or distribution. It has the disadvantage of not being able to continuously process gas since there is no system that can continuously process it during the distribution process. Therefore, in order to minimize changes in freshness and quality during the distribution process of agrifood, there is a need for a sustained-release chlorine dioxide gas treatment technology that can be continuously released. Therefore, in this study, the film to be used was examined so that the chlorine dioxide gas can be continuously released for a certain period of time, the concentration of the reactant and the viscosity at the time of the reaction were determined, and a chlorine dioxide gas gel pack was manufactured using this optimal condition. In addition, the gel pack was used to measure the amount of chlorine dioxide gas released and the sterilization effect of food poisoning bacteria.

Transmission Electron Microscopy Observation of (202) and (211) Twins in Monoclinic $ZrO_2$ Thin Film

  • Cheol Seong Hwang;Geun Hong Kim;Chang Hwan Chum;Hyeong Joon Kim
    • The Korean Journal of Ceramics
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    • v.1 no.3
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    • pp.143-146
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    • 1995
  • Twins along(202) and (211) planes are observed in monoclinic $ZrO_2$ thin film, which is deposited on Si substrate by MOCVD at $350^{\circ}C$ and annealed at $1150^{\circ}C$ for 10 hours in air. These types of twin have not been reported in monoclinic $ZrO_2$. The twins seem to be originated from the two dimensional tensile stresses applied to the $ZrO_2$ thin film due to the different thermal expansions of $ZrO_2$ thin film and Si substrate.

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Performance optimization of marine propellers

  • Lee, Chang-Sup;Choi, Young-Dal;Ahn, Byoung-Kwon;Shin, Myoung-Sup;Jang, Hyun-Gil
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.2 no.4
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    • pp.211-216
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    • 2010
  • Recently a Wide Chord Tip (WCT) propeller has been developed and applied to a commercial ship by STX Offshore & Shipbuilding. It is reported that the WCT propeller significantly reduces pressure fluctuations and also ship's noise and vibration. On the sea trial, vibration magnitude in the accommodations at NCR was measured at 0.9mm/sec which is only 10% of international allowable magnitude of vibration (9mm/sec). In this paper, a design method for increasing performance of the marine propellers including the WCT propeller is suggested. It is described to maximize the performance of the propeller by adjusting expanded areas of the propeller blade. Results show that efficiency can be increased up to over 2% through the suggested design method.

Enhanced Superconducting Properties in Melt-processed (Y0.33Sm0.33Nd0.33) Ba2Cu3Oy Oxides in Air

  • Kim, So-Jung;Park, Jong-Kuk
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.6
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    • pp.284-288
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    • 2005
  • We have systematically studied the superconducting properties and flux pinning enhancement of $(Y_{0.33}Sm_{0.33}Nd_{0.33})\;Ba_2Cu_3O_y$ [(YSN)-123] composite oxides by melt growth process in air. A sample prepared by this method showed well-textured microstructure, and $(Y_{0.33}Sm_{0.33}Nd_{0.33})\;BaCuO_5$ [(YSN)211] nonsuperconducting particles were uniformly dispersed in large (YSN) 123 superconducting matrix. The sample showed a sharp superconducting transition at 91 K. The magnetization measurements of the (YSN)-123 sample exhibited the enhanced flux pinning, compared with $YBa_2Cu_3O_y$ (Y-123) sample without Sm and Nd. Critical current densities of (YSN)-123 sample was $2.5{\times}10^4 A/cm^2$ at 2 T and 77 K.

Study of Earthquake Resilient RC Shear Wall Structures

  • Jiang, Huanjun;Li, Shurong
    • International Journal of High-Rise Buildings
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    • v.10 no.3
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    • pp.211-218
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    • 2021
  • A new type of earthquake resilient reinforced concrete (RC) shear wall structure, installed with replaceable coupling beams and replaceable corner components at the bottom of wall piers, is proposed in this study. At first, the mechanical behavior of replaceable components, such as combined dampers and replaceable corner component, is studied by cyclic loading tests on them. Then, cycling loading tests are conducted on one conventional coupled shear wall and one new type of coupled shear wall with replaceable components. The test results indicate that the damage of the new type of coupled shear wall concentrates on replaceable components and the left parts are well protected. Finally, a case study is introduced. The responses of one conventional frame-tube structure and one new type of structure installed with replaceable components under the wind and the earthquake are compared, which verify that the performance of new type of structure is much better than the conventional structure.

Analyzing Science Teachers' Understandings about Scientific Argumentation in terms of Scientific Inquiry

  • Park, Young-Shin
    • Journal of The Korean Association For Science Education
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    • v.28 no.3
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    • pp.211-226
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    • 2008
  • The purpose of this study was to investigate science teachers' understandings about scientific argumentation in the classroom. Seven structured interview protocols were developed, asking the definition of scientific inquiry, the differentiation between scientific inquiry and hands-on activity, the opportunity of student argumentation, explicit teaching strategies for scientific argumentation, the critical example of argumentation, the criteria of successful argumentation, and the barrier of developing argumentation. The results indicate that there are differences and similarities in understandings about scientific argumentation between two groups of middle school teachers and upper elementary. Basically, teachers at middle school define scientific inquiry as the opportunity of practicing reasoning skills through argumentation, while teachers at upper elementary define it as the more opportunities of practicing procedural skills through experiments rather than of developing argumentation. Teachers in both groups have implemented a teaching strategy called "Claim-Evidence Approach," for the purpose of providing students with more opportunities to develop arguments. Students' misconception, limited scientific knowledge and perception about inquiry as a cycle without the opportunity of using reasoning skills were considered as barriers for implementing authentic scientific inquiry in the classroom.

Determination of the Frumkin and Temkin Adsorption Isotherms of Underpotentially Deposited Hydrogen at Pt Group Metal Interfaces Using the Standard Gibbs Energy of Adsorption and Correlation Constants

  • Chun, Jinyoung;Jeon, Sang K.;Chun, Jang H.
    • Journal of the Korean Electrochemical Society
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    • v.16 no.4
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    • pp.211-216
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    • 2013
  • At Pt(111), Pt(100), Pt, and Rh interfaces, the Frumkin adsorption isotherm of underpotentially deposited hydrogen (UPD H) and related electrode kinetic data are determined using the standard Gibbs energy of adsorption. The Temkin adsorption isotherm of UPD H correlating with the Frumkin adsorption isotherm of UPD H is readily determined using the correlation constants between the Temkin and Frumkin or Langmuir adsorption isotherms. At the Pt(111), Pt(100), Pt, and Rh interfaces, the lateral repulsive interaction between the UPD H species is interpreted using the interaction parameter for the Frumkin adsorption isotherm. The lateral repulsive interaction between the UPD H species at the Pt(111), Pt(100), Pt, and Rh interfaces is significantly different from the lateral attractive interaction between the overpotentially deposited hydrogen (OPD H) species at Pt, Ir, and Pt-Ir alloy interfaces.

Characterization and Identification of Lactic Acid Bacteria Isolated from Fermented Milks in Iran (이란 발효 유제품에서 분리한 유산균의 특성)

  • Hyoju Park;Dong-June Park;Sejong Oh
    • Journal of Dairy Science and Biotechnology
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    • v.41 no.4
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    • pp.211-218
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    • 2023
  • This study aimed to identify lactic acid bacteria isolated from eight fermented milk products in Iran. We enumerated Lactobacillus species using De Man-Rogosa-Sharpe (MRS)-maltose and MRS agar with pH adjusted to 5.2, as well as assessment at 37℃ for 48 hr, studied Streptococcus spp. using M17 agar at 43℃ for 24 hr, and assessed Bifidobacterium species using nalidixic acid, paromomycin sulfate, neomycin sulfate, and lithium chloride (BL-NPNL) agar at 37℃ for 48 hr. The total viable Streptococcus spp. cell in fermented milk varied at 4.73-8.83 log CFU/mL. However, Bifidobacterium spp. were not detected in any of the tested samples. Lactobacilli were not detected in four of the eight samples, and viable Lactobacilli cells in the remaining four samples ranged 2.48-3.85 log CFU/mL. The pH of the tested samples ranged 3.53-4.19, and soluble solids (Brix measurement) ranged 7.5%-17.9%. A total of 130 isolates of gram-positive catalase-positive bacteria were characterized at the species level using 16S rRNA sequencing. Sequence analysis identified six species: Streptococcus thermophilus, Lactobacillus delbrueckii subsp. sunkii, Lactobacillus delbrueckii subsp. indicus, Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and Levilactobacillus brevis.