• Title/Summary/Keyword: Seon-bi

Search Result 122, Processing Time 0.03 seconds

Electrical and structural properties of BNT/BT multilayered thick films (BNT/BT 다층 박막의 구조적, 전기적 특성)

  • Nam, Sung-Pill;Noh, Hyun-Ji;Lee, Sung-Gap;Bea, Seon-Gi;Lee, Young-Hie
    • Proceedings of the KIEE Conference
    • /
    • 2009.07a
    • /
    • pp.1324_1325
    • /
    • 2009
  • The heterolayered $BaTiO_3/(Bi_{0.5}Na_{0.5})TiO_3$ thick films were fabricated by screen printing techniques on alumina substrates electrodes with Pt. We report the improved ferroelectric properties in the heterolayered teteragonal/rhombohedral structure composed of the $BaTiO_3$ and the $(Bi_{0.5}Na_{0.5})TiO_3$ thick films. We investigated the effects of deposition conditions on the structural and electrical properties of the heterolayered BNT/BT thick films. The structural and electrical properties of the heterolayered BNT/BT thick films were studied. All PZT heterolayered thin films show dense and homogeneous structure without the presence of the rosette structure. The dielectric constant, loss and remanent polarization oft heheterolayered BNT/BT thick films were superior to those of single composition $BaTiO_3$ and $(Bi_{1/2}Na_{1/2})TiO_3$, and those values for the heterolayered BNT/BT thick films sintered at $1100^{\circ}C$ were 916, 0.79 and $12.63{\mu}C/cm^2$.

  • PDF

Implementation of Bi-directional Optic EtherCAT Communication Module based on WDM Method (WDM 방식의 양방향 광 이더캣 통신 모듈 구현)

  • Moon, Yong-Seon;Roh, Sang-Hyun;Jo, Kwang-Hun;Bae, Young-Chul
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.7 no.2
    • /
    • pp.409-415
    • /
    • 2012
  • Recently in industry communication, the efforts that use robot and automation system increased by cooperation with optical communication and industrial Ethernet. In this paper, in order to solve the problem that total network blocking when network fault happens and wiring problem of optical cable, which were big serious disadvantage in industrial optical network systems, we propose bi-directional optical EtherCAT communication technique based on single optical core, which applying WDM method. We describe the content for implementation of WDM bi-directional optical EtherCAT communication module and performance evaluation to verify the performance of related technology as a whole.

Effect of Reduced Graphene Oxide in Photoanode on Photoelectrochemical Performance in Water Splitting for Hydrogen Production (수소생산을 위한 물 분해용 광전극에 도입된 환원된 산화그래핀이 광전기화학성능에 미치는 영향)

  • YOON, SANGHYEOK;DING, JIN-RUI;KIM, KYO-SEON
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.27 no.4
    • /
    • pp.329-334
    • /
    • 2016
  • Hydrogen is eco-friendly alternative energy source and the photoelectrochemical water splitting is believed to be one of the promising methods for hydrogen production. Many researchers have studied several potential photocatalysts to increase the photoelectochemical performance efficiency for hydrogen conversion. In this study, the GO (graphene oxide) was prepared by Tour's method and was dispersed in precursor solutions of $WO_3$ and $BiVO_4$. Those precursor solutions were spin-coated on FTO glass and several photocatalyst thin films of $WO_3$, $BiVO_4$ and $WO_3/BiVO_4$ were prepared by calcination. The morphologies of prepared photocatalyst thin films were measured by scanning electron microscope. The photoelectrochemical performances of photocatalyst thin films with rGO (reduced graphene oxide) and without rGO were analyzed systematically.

Catalytic mechanism and inhibition studies of purine nucleoside phosphorylase (PNP) in micrococcus luteus

  • Choi, Hye-Seon
    • Journal of Microbiology
    • /
    • v.35 no.1
    • /
    • pp.15-20
    • /
    • 1997
  • Kinetic studies were done to elucidate the reaction mechanism of purine nucleoside phosphorylase (PNP) in Micrococcus Luteus. PNP catalyzes the reversible phosphorolysis of ribonucleosides to their respective base. The effect of alternative competing substrates suggested that a single enzyme was involved in binding to the active site for all purine nucleosides, inosine, deoxyiosine, guanosine, deoxyguanosine, adenosine and deoxyadenosine. Affinity studies showed that pentose moiety reduced the binding capacity and methylation of ring N-1 of inosine and guanosine had little effect on binding to bacterial enzyme, whereas these compounds did not bind to the mammalian enzymes. The initial velocity and product inhibition studies demonstrated that the predominant mechanism of reaction was an ordered bi, bi reaction. The nucleoside bound to the enzyme first, followed by phosphate. Ribose 1-phosphate was the first product to leave, followed by base.

  • PDF

Reaction Mechanism of Purine Nucleoside Phosphorylase and Effects of Reactive Agents for SH Group on the Enzyme in Saccharomyces cerevisiae (Saccharomyces cerevisiae에서 얻은 Purine Nucleoside Phosphorylase의 반응기작과 효소에 대한 Sulfhydryl Reagent의 영향)

  • Choi, Hye-Seon
    • Korean Journal of Microbiology
    • /
    • v.32 no.3
    • /
    • pp.222-231
    • /
    • 1994
  • Kinetic analysis was done to elucidate the reaction mechanism of purine nucleoside phosphorylase (PNP) in Saccharomyces cerevisiae. The binary complexes of PNP${\cdot}$phosphate and PNP${\cdot}$ribose 1-phosphate were involved in the reaction mechanism. The initial velocity and product inhibition studies demonstrated were consistent with the predominant mechanism of the reaction being an ordered bi, bi reaction. The phosphate bound to the enzyme first, followed by nucleoside and base were the first product to leave, followed by ribose 1-phosphate. The kinetically suggested mechanism of PNP in S. cerevisiae was in agreement with the results of protection studies against the inactivation of the enzyme by sulfhydryl reagents, p-chloromercuribenzoate (PCMB) and 5,5'-dithiobisnitrobenzoate (DTNB). PNP was protected by ribose 1-phosphate and phosphate, but not by nucleoside or base, supporting the reaction order of ordered bi, bi mechanism. PCMB or DTNB-inactivated PNP was totally reactivated by dithiothreitol (DTT) and the activity was returned to the level of 77% by 2-mercaptoethanol, indicating that inactivation was reversible. The kinetic behavior of the PCMB-inactivated enzyme had been changed with higher $K_m$ value of inosine and lower $V_m$, and was restored by DTT. Inactivation of enzyme by DTNB showed similar pattern of K sub(m) value with that by PCMB, but had not changed the $V_m$ value, significantly. Negative cooperativity was not found with PCMB or DTNB treated PNP at high concentration of phosphate.

  • PDF

The Optical Properties of B2O3-Bi2O3-PbO-SiO2 Glass System (B2O3-Bi2O3-PbO-SiO2계 유리의 광학적인 특성)

  • Joung, Maeng Sig;Kim, Hong Seon;Lee, Su Dae
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.5 no.2
    • /
    • pp.167-173
    • /
    • 2000
  • Four glasses of $B_2O_3-Bi_2O_3-PbO-SiO_2$ (BBPS) system were prepared by melting the appropriate amounts of reagent grade oxides of $B_2O_3$, $Bi_2O_3$, PbO, and $SiO_2$ in an open crucible. The differential thermal analysis showed crystallization temperature decreased with increasing $Bi_2O_3$ or PbO content in the sample. The structures of glasses system were studied using scanning electron microscopy and Fourier transform-Infra red (FT-IR) spectroscopy. The UV cut-off and refractive index were found to be sensitive to the $Pb^{+2}$ and $Bi^{+3}$ content in the glasses. The behavior of the IR spectra of the glasses in the BP series was consistent with a role of $Bi_2O_3$ as a network former. In the BP series of glasses, the result of IR spectrum indicated that PbO behaved as a network former.

  • PDF

Characteristics of Sn-1.7Bi-0.7Cu-0.6In Lead-free Solder (Sn-1.7Bi-0.7Cu-0.6In 솔더의 특성 연구)

  • Park, Ji-Ho;Lee, Hee-Yul;Jhun, Ji-Heon;Cheon, Chu-Seon;Jung, Jae-Pil
    • Journal of Welding and Joining
    • /
    • v.26 no.5
    • /
    • pp.43-48
    • /
    • 2008
  • Characteristics of Sn-1.7%Bi-0.7%Cu-0.6%In (hereafter, SBIC) lead-free solder was investigated in this study. The results from SBIC were compared to other lead-free solders such as Sn-3.5%Ag-0.7%Cu (hereafter, SAC), Sn-0.7%Cu (hereafter, SC), and lead-bearing Sn-37%Pb (hereafter, SP) alloy. Tensile properties of bulk solder, wettability, spreading index, bridge and dross were evaluated. As experimental results, tensile strength and elongation of SBIC was 62.5MPa and 21.5%, respectively. The tensile strength was comparable to that of SP solder. The wetting time of SBIC was 1.2 sec at $250^{\circ}C$, and its wetting properties including wetting force were as good as the SAC alloy. However, wettability of the SC was not so good as the SBIC and SAC. The spreading index of SBIC at $250^{\circ}C$ was 71 %, and it was similar level to those of SAC and SC solders. Bridging was not found for all solders of SBIC, SAC and SC in the range from 240 to $260^{\circ}C$. In dross test at $250^{\circ}C$ for an hour, the amount of dross produced from SBIC was about 57% compared to that from SAC.

Evaluation of SWMM Snow-melt Module to Secure Bi-Modal Tram Operation (바이모달 트램 운행 안전성 확보를 위한 SWMM 융설 모듈 적용성 평가)

  • Kim, Jong-Gun;Park, Young-Kon;Yoon, Hee-Taek;Park, Youn-Shik;Jang, Won-Seok;Yoo, Dong-Seon;Lim, Kyoung-Jae
    • Journal of the Korean Society for Railway
    • /
    • v.11 no.5
    • /
    • pp.441-448
    • /
    • 2008
  • Increasing urban sprawl and climate changes have been causing unexpected high-intensity rainfall events. Thus there are needs to enhance conventional disaster management system for comprehensive actions to secure safety. Therefore long-term and comprehensive flood management plans need to be well established. Recently torrential snowfall are occurring frequently, causing have snow traffic jams on the road. To secure safety and on-time operation of the Bi-modal tram system, well-structured disaster management system capable of analyzing the show pack melt/freezing due to unexpected snowfall are needed. To secure safety of the Bi-modal tram system due to torrential snow-fall, the snow melt simulation capability was investigated. The snow accumulation and snow melt were measured to validate the SWMM snow melt component. It showed that there was a good agreement between measured snow melt data and the simulated ones. Therefore, the Bi-modal tram disaster management system will be able to predict snow melt reasonably well to secure safety of the Bi-modal tram system during the winter. The Bi-modal tram disaster management system can be used to identify top priority area for know removal within the tram route in case of torrential snowfall to secure on-time operation of the tram. Also it can be used for detour route in the tram networks based on the disaster management system prediction.

Enhanced Thermoelectric Properties in n-Type Bi2Te3 using Control of Grain Size (Grain 크기 조절을 통한 n-Type Bi2Te3 열전 소재 특성 향상)

  • Lee, Nayoung;Ye, Sungwook;Jamil Ur, Rahman;Tak, Jang-Yeul;Cho, Jung Young;Seo, Won Seon;Shin, Weon Ho;Nam, Woo Hyun;Roh, Jong Wook
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.28 no.4
    • /
    • pp.91-96
    • /
    • 2021
  • The enhancement of thermoelectric figure of merit was achieved by the simple processes of sieving and high energy ball milling, respectively, which are enable to reduce the grain size of n-type Bi2Te3 thermoelectric materials. By optimizing the grain size, the electrical conductivities and thermal conductivities were controlled. In this study, spark plasma sintering was employed for hindering the grain growth during the sintering process. The thermoelectric figure of merit was measured to be 0.78 in the samples with 30 min high energy ball milling process. Notably, this value was 40 % higher than that of pristine Bi2Te3 sample. This result shows the properties of thermoelectric materials can be readily controlled by optimization of grain size via simple ball milling process.