• Title/Summary/Keyword: Structural Transition

Search Result 728, Processing Time 0.034 seconds

Leverage Strategy to National R&D Investment in Korea: A System Dynamics Approach (국가 연구개발 투자시스템의 레버리지 전략: 시스템 다이내믹스 접근)

  • Park, Hun-Joon;Oh, Se-Hong;Kim, Sang-Jun
    • Korean System Dynamics Review
    • /
    • v.5 no.2
    • /
    • pp.33-66
    • /
    • 2004
  • This study is an exploratory investigation on how national R&D investments decisions are made in Korea. For developing system dynamic model, we are interested in locating three structural dilemma, occurring with the Korean NIS. In so doing, we intend to devise the ways of ameliorating problems within the NIS investment decision-making process by providing policy implications. We identify delays and side effects during transition periods between different stages of technology innovation by perceiving the switching pattern dynamically, in which form of technologies shifts from one to another stage like paradigm shift, when the R&D investment reaches a certain stock. It is also suggested that the development of strategies is necessary in order to enhance efficiency of technological development process.

  • PDF

Effect of Cu substitution on Superconductivity in $(Ru_{1-x}Cu_x)Sr_2(Eu_{1.34}Ce_{0.66})Cu_2O_z$ System (Cu 치환에 따른 $(Ru_{1-x}Cu_x)Sr_2(Eu_{1.34}Ce_{0.66})Cu_2O_z$ 계의 초전도 특성)

  • Lee, H.K.
    • Progress in Superconductivity
    • /
    • v.11 no.1
    • /
    • pp.67-71
    • /
    • 2009
  • The effect of Cu substitution on the structural and superconducting properties of the $(Ru_{1-x}Cu_x)Sr_2(Eu_{1.34{\cdot}}Ce_{0.66})Cu_2O_z$ system with x = 0, 0.25 and 0.5 prepared under ambient pressure have been investigated. The X-ray diffraction patterns indicated that the Ru ions are replaced by the Cu ions. It is found that the Cu substitution for Ru significantly reduces the ferromagnetic component of field-cooled magnetic susceptibility, but results in a small change in diamagnetic onset transition temperature of zero-field-cooled magnetic susceptibility. In contrast to the Ru $Sr_2(Eu_{1.34{\cdot}}Ce_{0.66})Cu_2O_z$, bulk Meissner effect is observed in the field-cooled magnetization measurements of the Cu doped samples. The experimental results are discussed in connection with the spontaneous vortex phase interpretation.

  • PDF

Selective Response of Dye Rotaxane to Metal Ions (금속 이온에 대한 염료 로택산의 선택적 반응성)

  • Park, Jong-S.
    • Proceedings of the Korean Society of Dyers and Finishers Conference
    • /
    • 2011.03a
    • /
    • pp.35-35
    • /
    • 2011
  • The design and preparation of novel dye rotaxanes have gained much interest recently, since such structure usually exhibits peculiar spectral and optical changes. In spite of the promising results to date, increasing pressure remains to develop novel supramolecular structures based on stimuli-responsive systems. This presentation covers the study of inclusion complexes of cyclodextrins and various chromophores, with an emphasis on our most recent outcome of anisotropic hydrogel. In this system, physical gelation prepared from simple mixture of CD and a azo dye is completed through specific host-guest interaction. The obtained hydrogel exhibits respective morphological transitions based on supramolecular assembly and dissociation, leading to either precipitation or a sol-to-gel transition. It can identify different classes of metal ions, and, among them, naked-eye differentiation of lead ion is possible due to the coordination-induced unthreading of dye molecules. Accompanying structural changes were verified by numerous characterization techniques, including 2D-ROESY, HR-MAS, UV-Visible absorption, small-angle X-ray scattering, and induced circular dichroism measurements. Such properties discussed here will find useful in analytical applications, such as metal ion sensing and removal applications.

  • PDF

Identification of a Regulatory Region within the luxR Structural Gene in a Marine Symbiotic Bacterium, Vibrio fischeri

  • Choi, Sang-Ho
    • Journal of Microbiology and Biotechnology
    • /
    • v.4 no.3
    • /
    • pp.176-182
    • /
    • 1994
  • The light-organ symbiont of pine cone fish, Vibrio fischeri, senses its presence in the host and responds to environmental changes by differentially expressing its symbiosis-related luminescence genes. The V. fischeri luminescence genes are activated by LuxR protein in the presence of an autoinducer. In an effort to elucidate the mechanism of regulation of luxR, a plasmid containing luxR was mutagenized in vitro with hydroxylamine and a luxR mutant plasmid was isolated by its ability to activate luminescence genes cloned in E. coli in the absence of the autoinducer. The specific base change identified by DNA sequencing was only single base transition at +78 from the transcriptional start of luxR. Based on a Western immunoblot analysis, the nucleotide change directed the synthesis of much higher level of LuxR protein without any amino acid substitutions. The results suggest that the region including the +78th base is presumably internal operator required for autorepression of luxR, and the increased cellular level of LuxR results in activation of luminescence genes by autoinducer independent fashion.

  • PDF

Sensitivity analysis for seismic response of a ship-block system

  • Kuchaksarai, Masoud Moghaddasi;Bargi, Khosrow
    • Structural Engineering and Mechanics
    • /
    • v.23 no.3
    • /
    • pp.309-323
    • /
    • 2006
  • In this paper, seismic response of a free-standing ship located in a dry dock and supported by an arrangement of n keel blocks due to base excitation is addressed. Formulation of the problem including derivation of governing equations in various modes of motion as well as transition conditions from one mode to another is given in Moghaddasi and Bargi (2006) by same authors. On the base of numerical solution for presented formulation, several numbers of analyses are conducted to study sensitivity of system's responses to some major contributing parameters. These parameters include friction coefficients between contacting surfaces, block dimensions, peak ground acceleration, and the magnitude of vertical ground acceleration. Finally, performance of a system with usual parameters normally encountered in design is investigated.

$^{87}Rb$ NMR Quadrupole Coupling Constants and Asymmetry Parameters in $RbMnCl_3$

  • Woo, Ae-Ja;Park, Young-Sun
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.3 no.2
    • /
    • pp.84-89
    • /
    • 1999
  • The 87Rb quadrupole coupling constants (e2qQ/h) and the asymmetry parameters (η) in RbMnCl3 were determined from a nonlinear least-squares fit to the 87Rb NMR powder spectra. The spectra were acquired in the temperature range from 260K to 330K. An important feature in this work is the determination of the quadrupole coupling constants and the asymmetry parameters for two physically nonequivalent Rb sites, Rb(I) and Rb(II), as a function of temperature. In addition, a structural phase transition at room temperature was conformed with the changes in the quadrupole coupling constant and the asymmetry parameter of Rb(II) site.

  • PDF

The Impact of the Organizational Characteristics, IS Basis, IS Planning Capability and IS Quality on the CRM Performance (조직특성, IS 기반, IS 기획능력 및 IS 품질이 CRM 성과에 미치는 영향)

  • Lee, Seung-Myoung;Kim, Eun-Hong
    • Journal of Information Technology Services
    • /
    • v.4 no.1
    • /
    • pp.71-105
    • /
    • 2005
  • The purpose of this study was to test various variables that affect CRM performance in order to evaluate CRM performance. The results of the proposed research hypotheses are as follows; First, the IS based factors perform more important roles on system and information quality compared to organizational factors. Second, the variables of IS and planning capability playa role as a parameter. Third, among organizational factors, non-structural factors such as degrees of acceptance of business transition, support of CEO, and customer-orientation perform more important roles on CRM. Fourth, IS based factors have bigger Impact on information quality than system quality. Fifth, it was proven that IS quality, proposed as a parameter and as a dependant variable, and CRM have significant relations.

Tuning of the ferromagnetic transition by impurity doping in Ru$Sr_2$EuCe$Cu_2$$O_z$ (불순물 치환을 통한 Ru$Sr_2$EuCe$Cu_2$$O_z$ 계의 강자성 천이온도의 조절특성)

  • Lee H. K;Kim Y. H;Kwon O. H
    • Progress in Superconductivity
    • /
    • v.6 no.1
    • /
    • pp.37-40
    • /
    • 2004
  • We investigated the effects of impurity doping on the electrical transport and magnetic properties of TEX>$(Ru, Sn)(Sr, La)<_2$$EuCeCu_2$$O_{z}$ samples. We found that Sn substitution fur Ru causes a significant decrease of the volume fraction of ferromagnetic phase, as well as a decrease of the temperature where the ferromagnetic component is observed. La substitution for Sr leads to an increase of the magnetic ordering temperature with a moderate change of ferromagnetic component. The experimental results are discussed in conjunction with the structural data, transport properties and a possible change of oxygen content.

  • PDF

Characteristics of InSb MIS device prepared by remote PECVD SiO$_{2}$ (Remote PECVD SiO$_{2}$ 를 이용한 InSb MIS 소자의 특성)

  • 이재곤;최시영
    • Journal of the Korean Institute of Telematics and Electronics A
    • /
    • v.33A no.12
    • /
    • pp.59-64
    • /
    • 1996
  • InSb MIS devices prepared by remote PECVD SiO$_{2}$ were fabricated. The SiO$_{2}$ films on InSb were deposited at atemperature range of 67~190$^{\circ}$C. The effects of deposition temperature on the structural characteristics of the SiO$_{2}$ films evaluated Auger electron spectroscopy showed that atomic raito of silicon to oxygen was 0.5 and composition toms were distributed uniformaly throuout the oxide film. The transition region is about 100$\AA$ for SiO$_{2}$/InSb interface. The leakage current density at 1MV/cm and the breakdownelectric field of the MiS device using SiO$_{2}$ film deposited at 105$^{\circ}$C were about 22 nA/cm$^{2}$ and 3.5MV/cm, respectively. The interface-state density at mid-bandgap extracted from 1 MHz high frequency C-V measurement was about 2X10$^{11}$ cm$^{-2}$eV$^{-1}$.

  • PDF

The structure and properties of $50SnO_2-(50-x)P_2O_5-xB_2O_3$ for component materials of PDP

  • An, Yong-Tae;Choi, Byung-Hyun;Ji, Mi-Jung;Ko, Young-Soo;Kim, Hyung-Sun
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2008.10a
    • /
    • pp.359-361
    • /
    • 2008
  • Glasses in the $SnO_2-(50-x)P_2O_5-xB_2O_3$ system were examined as potential replacement for the PbO glass frits with low firing temperature for component materials of a plasma display panel. The glasses were evaluated for their structural and the thermal expansion coefficient, glass transition and glass softening temperatures and Vickers hardness as a function of the $B_2O_3$ content.

  • PDF