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Synthesis and Characterization of 1-D BiSI and 2-D BiOI Nanostructures

  • Lee, Juheon;Min, Bong-Ki;Cho, Insu;Sohn, Youngku
    • Bulletin of the Korean Chemical Society
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    • v.34 no.3
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    • pp.773-776
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    • 2013
  • We have prepared 1-D BiSI and 2-D BiOI nanostructures, and characterized them by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction crystallography, thermogravimetric analysis/differential scanning calorimetry, and UV-visible absorption. Here, we first report clear HR-TEM image of BiSI. In addition, we first found that the growth direction of BiSI is [12-1] plane, with the neighboring distance of 0.30 nm. The crystal structures of BiSI and BiOI are found to be orthorhombic (Pnam) and tetragonal (P4/nmm), respectively. The absorption band gaps of BiSI and BiOI are measured to be 1.55 and 1.92 eV, respectively. Our study could further highlight the applications of V-VI-VII compounds.

On some properties of vague bi-groups and fuzzy bi-functions (애매 bi-군과 퍼지 bi-함수의 성질에 관한 연구)

  • Jang, Lee-Chae;Kim, Tae-Kyun;Lee, Byung-Je;Kim, Won-Joo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.20 no.3
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    • pp.356-361
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    • 2010
  • M. Demirci[Vague groups, J. math. Anal. Appl. vol.230, pp. 142-156, 1999] studied the vague group operation on a crisp set as a fuzzy function and estabished the vague group structure on a crisp set. In this paper we consider bi-groups which are studied by A.A.A. Agboola and L.S. Akinola. And we also will define vague bi-groups and fuzzy bi-functions and we investigate some basic operations on the vague bi-group and fuzzy bi-functions.

The Effect of Bismuth Composition Controlled by Heat Treating Heterostructure on the Ferroelectric Properties of SrBi$_2$Ta$_{2-x}$Nb$_x$O$_9$ Thin Films (Heterostructure 열처리에 의한 Bi 조성 제어가 SrBi$_2$Ta$_{2-x}$Nb$_x$O$_9$ 박막의 강유전 특성에 미치는 영향)

  • 박윤백;이전국;정형진;박종완
    • Journal of the Korean Ceramic Society
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    • v.35 no.10
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    • pp.1040-1048
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    • 1998
  • Ferroelectric properties of{{{{ { { { {SrBi }_{2 }Ta }_{2-x }Nb }_{x }O }_{9 } }} (SBIN) thin films were affected by the amount of Bi content in SBTN. The addition of Bi into the SBTN films could be accomplished by heat treating SBTN/Bi2O3/SBTN het-erostructures fabricated by r.f. magnetron sputtering method. The variation of Bi content was controlled by changing the thickness of the sandwiched Bi2O3 in SBTN/Bi2O3/SBTN heterostructure from 50 to 400$\AA$. As changing the thickness of the sandwiched Bi2O3 in Bi2O3 films was increased from 0 to 100$\AA$ the grain grew faster and the ferroelectric pro-perties were improved. On the other hand when the thickness of Bi2O3 films was thicker than 150$\AA$ the fer-roelectric properties were deteriorated Especially for SBTN thin films inserted by 400$\AA$ Bi2O3 layer a Bi2Phase appeared as a second phase resulting in poor ferroelectric properties. The maximum remanent po-larization (2Pr) and coercive field(Ec) were obtained for the SBTN/Bi2O3/(100$\AA$)/SBTN thin films. In this case 2Pr and Ec were 14.75 $\mu$C/cm2 and 53.4kV/cm at an applied voltage of 3V respectively.

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Phase Analyses and Magnetic Properties of $Mn-(M,AI)_{1-x}(Bi,Sb)_x$(M=Cu, Fe) Alloy Systems ($Mn-(M, AI)_{1-x}(Bi, Sb)_x$ (M=Cu, Fe)합금계의 상 분석 및 자기적 성질에 관한 연구)

  • Park, Jung-Eon;Go, Gwan-Yeong;Yun, Seok-Gil
    • Korean Journal of Materials Research
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    • v.6 no.1
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    • pp.90-98
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    • 1996
  • Mn((Cu0.66AI0.34)1-x(Bi0.3Sb0.7)x) 및 Mn((Fe0.66AI0.34)1-x(Bi0.3Sb0.7)x) 합금계의 상의 변화와 자기적 특성을 조사하였다. Mn((Cu, SI)(Bi, Sb)) 합금계는 Bi상, MnSb상, MnBi상, k-상, Heuser상, Mn2Sb 및 $\beta$-Mn상의 혼합상으로 이루어졌으며 x가 증가함에 따라 Bi상과 Mn2Sb상이 증가하고 K-상, Heusler상 및 $\beta$-Mn상이 줄어들거나 사라졌다. 자기적 성질은 자성을 띄는 MnSb상, MnBi상, Mn2Sb상, k-상 및 Hseusler상과 비자성인 Bi상과 $\beta$-Mn상의 상대적 분율에 의해 결정됨을 알 수 있었고, 150K-200K 부근에서 그 이하로 온도가 감소함에 따라 자화값이 급격히 감소하는 현상이 나타났다. Mn((Fe, AI)(Bi, Sb))합금계는 Bi상, MnSb상, MnBi상, MnBi상,$\beta$-Mn상, k-상 및 Mn2Sb상의 혼합상으로 나타났으며, 자기적 성질은 조사한 전 조성에서 강자성을 띄고 있음을 알 수 있었다.

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Characterization of amorphous Sb-Bi-Te thin films as a function of Bi concentration (Bi 농도에 따른 비정질 Sb-Bi-Te 박막의 특성)

  • ;D. Mangalaraj
    • Journal of the Korean Vacuum Society
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    • v.11 no.1
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    • pp.28-34
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    • 2002
  • Thin films of $Sb_{2-x}Bi_xTe_3$ (x = 0.0, 0.5, and 1.0) are grown by vacuum evaporation. XRD analysis shows the amorphous nature of the films, and the composition studies confirm the stoichiometry of the films. Microstructural parameters of the films have been calculated and used to explain the electrical and optical properties of the films. It is observed that the carrier type has changed from p- to n-type at higher concentration (x = 1.0) of Bi. The resistivity of the films decreases rapidly with the increase of Bi concentration. However, the refractive index and optical band gap of the films increase with the Bi concentration.

Technique development of Bi-2212/2223 superconductor thick film manufacturing by plasma spraying and heat treatment (플라즈마 용사 및 열처리 공정을 통한 Bi-2212/2223 초전도체 thick film 제조의 기술 개발)

  • Lee, Seon-Hong;Cho, Sang-Hum;Ko, Young-Bong;Park, Kyeung-Chae
    • Proceedings of the KWS Conference
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    • 2005.11a
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    • pp.262-264
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    • 2005
  • $Bi_{2}Sr_{2}CaCu_{2}O_{x}$(Bi-2212) and $Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{y}$(Bi-2223) high-$T_{c}$ superconductor(HTS) coating have been prepared by plasma spraying and heaat treatment. The Bi-2212 HTS coating later is synthesized through the peritectic reaction between Sr-Ca-Cu oxide coating layer and Bi-Cu oxide coating later, and $Bi_{2}Sr_{2}CaCu_{2}O_{y}$(Bi-2212) superconducting phase grow by partial melting process. The superconducting characteristic depends strongly on the conditions of the partial melting process. the Bi-2212 HTS layer consists of the whiskers grown in the diffusion direction. Above the 2212 layer, Bi-2223 phase and secondary phase was observed. The secondary phase is distributed uniformly over the whole surface. This is caused to the microcrack on the coatings surface. Despite everything, the film shows superconducting with an onset $T_{c}$ of about 115K. There are two changes steps. One changes (1step) at 115K is due to the diamagnetism of the Bi-2223 phase and the other changes (2step) at 78K is due to the diamagnetism of the Bi-2212 phase.

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Sticking Characteristics in Bi2Sr2CanCun+1Ox Thin Films Fabricated by using the Evaporation Method to Improve the Sticking Ratio (부착율 개선을 위해 증발 법으로 제작한 Bi2Sr2CanCun+1Ox 박막의 부착 특성)

  • 천민우;박용필
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.11
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    • pp.1029-1034
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    • 2003
  • The Bi$_2$Sr$_2$Ca$_{n}$Cu$_{n+1}$ O$_{x}$, superconducting thin films arc fabricated by using the sputtering and evaporation method. Because we confirmed the sticking ratio of Bi element in the Bi$_2$Sr$_2$Ca$_{n}$Cu$_{n+1}$ O$_{x}$ superconducting thin film fabricated by using the sputtering method was much lower than the expected value, to get the enough number of the flakes of Bi, faraday cup was used to evaporate Bi clement. As a result of the fabrication, Bi 2201 and Bi 2212 single phases could be made by the optima of deposition condition. And we confirmed the sticking coefficient of Bi element was clearly related to the temperature change of the substrate and the generation of Bi22l2 phase

The Empirical Study on Relationship Between Evaluation Index Characteristics for Occupancy of Business Incubator(BI) and BI Performance : focused on the Moderating Effect of BI Competence (창업보육센터(BI) 입주심사지표특성과 성과의 관계에 관한 실증연구 -BI 역량의 조절효과를 중심으로)

  • Park, Man-Hee;Yang, Dong-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.1
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    • pp.233-247
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    • 2011
  • With recent increase in growth without employment and unemployment rate, Business Incubator (BI), which is the birthplace of business start-up, is drawing much attention. Therefore, numerous studies had been carried out from the perspectives of efficient operation and performances of BI. Preceding studies at home and abroad were concentrated mainly on the effect of Critical Success Factors of BI on performance, or on internal operational programs or support services of BI. Recently, assertion that potential capacity of companies located in BI at the time of their commencement of occupancy imparts effect on the performance has been presented. Therefore, this Study, in order to pursue research on above issues, will, firstly, analyze the effect of the characteristics of evaluation of companies wishing to be located in BI conducted by each BI, and, secondly, regulation effect of characteristics of evaluation of companies wishing to be located in BI imparted on performance in connection with the work capabilities of BI and capabilities of manager. The results of analysis illustrated that the expertise, among the capabilities of CEO, imparts affirmative effect on the success rate of business start-up. Product competitiveness and marketability displayed affirmative effect on the success rate of business start-up when work capability (operational intensity) is applied. In particular, although the financing capability of CEO of the company located in BI, as an important factor, imparts negative effect on the success rate of business start-up, it implies affirmative regulation effect through the capabilities of manager.

Optical Properties of Photoferroelectic Semiconductors IV.(Optical Properties of SbSI:V, SbSeI:V, BiSI:V, BiSeI:V, SbSI:Cr, SbSeI:Cr, BiSI:Cr, BiSeI:Cr, SbSI:Ni, SbSeI:Ni, BiSI:Ni and BiSeI:Ni Single Crystals) (Photoferroelectric 반도체의 광학적 특성 연구 IV. (SbSI:V, SbSeI:V, BiSI:V, BiSeI:V, SbSI:Cr, SbSeI:Cr, BiSI:Cr, BiSeI:Cr, SbSI:Ni, SbSeI:Ni, BiSI:Ni 및 BiSeI:Ni 단결정의 광학적 특성에 관한 연구))

  • Oh, Seok-Kyun;Hyun, Seung-Cheol;Yun, Sang-Hyun;Kim, Wha-Tek;Kim, Hyung-Gon;Choe, Sung-Hyu;Yoon, Chang-Sun;Kwun, Sook-Il
    • Journal of the Korean Vacuum Society
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    • v.2 no.2
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    • pp.236-245
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    • 1993
  • Single crystals, SbSI : V, SbSeI : V, BiSI : V, BiSeI : V, SbSI : Cr, SbSeI : Cr, BiSI : Cr, BiSeI : Cr, SbSI : Ni, SbSeI : Ni, BiSI : Ni, and BiSeI : Ni were grown by the vertical Bridgman method. It is found that the grown single crystals have an orthorhombic structure and the indirect optical transitions. The temperature dependence of energy gap shows the two reflection point related with the phase transitions and is well fitted with Varshni equation in the continuous region. The optical absorption peaks due to the doped impurities (V, Cr and Ni) are respectively attributed to the electron transitions between the split energy levels of $V^{+2}$, $Cr^{+2}$ and $Ni^{+2}$ ions sited at $T_d$ symmetry of the host lattice.

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APPROXIMATE BI-HOMOMORPHISMS AND BI-DERIVATIONS IN C*-TERNARY ALGEBRAS: REVISITED

  • Cho, Young;Jang, Sun Young;Kwon, Su Min;Park, Choonkil;Park, Won-Gil
    • Korean Journal of Mathematics
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    • v.21 no.2
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    • pp.161-170
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    • 2013
  • Bae and W. Park [3] proved the Hyers-Ulam stability of bi-homomorphisms and bi-derivations in $C^*$-ternary algebras. It is easy to show that the definitions of bi-homomorphisms and bi-derivations, given in [3], are meaningless. So we correct the definitions of bi-homomorphisms and bi-derivations. Under the conditions in the main theorems, we can show that the related mappings must be zero. In this paper, we correct the statements and the proofs of the results, and prove the corrected theorems.