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A Study on the Development of Low Frequency Electronic Ignition Trans for Large Combustors (대형연소기에 적용되는 저주파 전자식 점화 트랜스 개발에 관한 연구)

  • Lee, Ho-kyun;Park, Jung-cheul
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.15 no.4
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    • pp.223-229
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    • 2022
  • In this paper, the ignition trans used in boilers was studied. Regardless of the change in the ignition rod length and the ignition rod gap, the output frequency was measured between 59.5 and 61.3 Hz, and it was found that the low frequency circuit operated normally. When the ignition rod gap changed by 2 to 10 mm, the ignition rod length was measured from 2.8A to 3.45A at 30cm. The ignition rod length was measured from 9.37 A to 14.5 A at 500 cm and from 13.2 A to 32.6 A at 1000 cm. As the ignition rod length and the ignition rod gap increased, the current increased. As a result of measuring the secondary coil output voltage. The ignition rod length was measured from AC 0.84 kV to AC 1.75 kV at 30 cm, AC 1.17 kV to AC 1.944 at 500 cm, and AC 1.4 kV to AC 7.18 kV at 1000 cm. As the ignition rod length and the ignition rod gap increased, the output voltage of the secondary coil also increased. As a result of measuring the output voltage of the ignition trans, the ignition rod length was measured from DC 1.11 kV to DC 1.57 kV at 30cm, DC 2.49 kV to DC 3.72 kV at 500cm, and DC 3.78 kV to DC 9.42 kV at 1000cm, and the power voltage increased as the ignition rod length and interval increased.

Charge/discharge Properties of $V_2O_5$-AC Composite for Supercapacitor (Supercapacitor용 $V_2O_5$-AC Composite의 충방전 특성)

  • 김명산;김종욱;구할본
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.366-369
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    • 1999
  • The purpose of this study is to research and develop V2Os-AC(activated carbon) composite electrode for supercapacitor. Supaercapacitor cell of V2Os-AC composite electrode with 25P70FLiCIO$_{4}$/PC$_{10}$/EC$_{10}$ polymer electrolyte bring out good capacitor Performance below 3V. The discharge capacitance of V2Os-AC(30:70) composite with 70wt.% AC in 1st and 200th cycles was 9.6 and 8.2 F/g at current density of 1m7/cm2. The capacitance of V$_2$O$_{5}$-AC composite with 70wt.% AC capacitor was larger than that of others. The coulombic efficiency of supercapacitor at discharge process of 1 and 200 cycles were 96 and 100%, respectively. V$_2$O$_{5}$-AC composite supercapacitor with 70wt.% AC content showed good capacitance and stability with cycling.ing.ing.

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Temperature Dependence of the Rate Constants of the VV Energy Exchange for N$_2$(v=1)+O$_2$(v=0)$\rightarrow$N$_2$(v=0)+O$_2$(v=1)

  • Ree, Jong-Baik;Chung, Keun-Ho;Kim, Hae-Jin
    • Bulletin of the Korean Chemical Society
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    • v.7 no.3
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    • pp.241-245
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    • 1986
  • The vibration-vibration energy exchange of $N_2(v=1)+O_2(v=0){\to}N_2(v=0)+O_2(v=1)$ has been investigated, in particular, at low temperatures. The energy exchange rate constants are calculated by use of the solution of the time-dependent Schrodinger equation with the interaction potential of the colliding molecule as a perturbation term. The predicted rate constants are significantly agree with a experimental values in the range of 295∼$90^{\circ}K$. The consideration of the VV-VT coupling decreases the predicted pure VV energy exchange value by a factor of ∼2. When the collision frequency correction is introduced, the VV-VT rate constant is consistent with the observed value in the liquid phase. The consideration of the population of the rotational energy level increases the VV-VT value significantly.

Low Temperature Selective Catalytic Reduction of NOx over V2O5/TiO2 Catalyst Doped with Mn (Mn이 첨가된 V2O5/TiO2 촉매상에서 질소산화물의 저온 SCR 특성)

  • Cheon, Tae Jin;Choe, Sang Gi;Choe, Seong U
    • Journal of Environmental Science International
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    • v.13 no.6
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    • pp.537-542
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    • 2004
  • $V_{2}O_{5}/TiO_{2}$ catalysts promoted with Mn were prepared and tested for selective catalytic reduction of NOx in $NH_3.$ The effects of promoter content, degree of catalyst loading were investigated for NOx activity while changing temperatures, mole ratio, space velocity and $O_2$ concentration. Among the various $V-{2}O_{5}$ catalysts having different metal loadings, $V-{2}O_{5}$(1 wt.%) catalyst showed the highest activity(98%) under wide temperature range of $200-250^{\circ}C.$ When the $V-{2}O_{5}$ catalyst was further modified with 5 wt.% Mn as a promoter, the highest activity(90-47%) was obtained over the low temperature windows of $100-200^{\circ}C.$ From Mn-$V_{2}O_{5}/TiO_{2}$, it was found that by addition of 5 wt.% Mn on $V_{2}O_{5}/TiO_{2}$ catalyst, reduction activity of catalyst was improved, which resulted in the increase of catalytic activity and NOx reduction. According to the results, NOx removal decreased for 10%, but the reaction temperature down to $100^{\circ}C.$

Synthesis and Characterization of a $Di-{\mu}-oxo-bridged$ Molybdeum(V) Complexes (두 개 산소 가교형 몰리브덴(V)착물의 합성과 그 성질에 관한 연구)

  • Kim, Il-Chool;Kim, Yeoung-Chan
    • Journal of the Korean Applied Science and Technology
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    • v.16 no.3
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    • pp.205-210
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    • 1999
  • The Mo(V) $di-{\mu}-oxo$ type $[Mo_2O_4(H_2O)_2L]Cl_2$ complexes(L: 4,4'-Diphenyl-2,2'-dipyridyl, 4,4'-Dimethyl-2,2'-dipyridyl, 4,7-Diphenyl-1,10-phenanthroline) have been prepared by the reaction of $[Mo_2O_4(H_2O)_6]^{2+}$ with a series of chelate ligands. These complexes are completed by two terminal oxygens arranged trans to one another and each ligand forms a chelate types. In $Mo_2O_4(H_2O)_2L$ two $H_2O$ coordinated at trans site of terminal oxgens. The prepared complexes have been characterized by elemental analysis, infrared spectra, electronic spectra, $^1H$ nuclear magnetic resonance spectra, and thermal analysis(TG-DTA). In the potential range -0.00V to -1.00V at scan rate of $50mVs^{-1}$, a cathodic peak at -0.83V ${\sim}$ -0.88V (vs SCE) and an anodic peak at -0.54V ${\sim}$ -0.88V (vs SCE) have been observed in aquous solution. The ratio of the cathodic to anodic current(Ipc/Ipa) is almost 2, we infer that redox is irreversible as dimer forms broken.

TTA 시험$\cdot$인증 서비스 - 소프트웨어 분야 -

  • 김혜경
    • TTA Journal
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    • s.87
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    • pp.162-168
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    • 2003
  • TTA(한국정보통신기술 협회)는 2003년 4월 7일 품질 인증제품으로 연희정보통신㈜의''상·하수도 범용/UFCom v 1.0'', ㈜뉴테크웨이브의 ''VirusChaser v 5.0''등 2개의 제품에 대하여 Good Software 마크를 발급하였다. 그리고 2003년 4월 30일에 ㈜웨어밸리의''Orange for ORACLE v 2.2'', ㈜테크다임의''Techdigm Office v 2.0'', ㈜엔지스 테크널러지의''G-Solution Waterworks/Sewerage v 1.0'', 삼성에스디에스㈜의''uniCITY Standard v 1.0'', ''uniCITY Enterprise v 1.0''등 5개의 제품에 대하여 Good Software 마크를 발급하였다. 본 고에서는 상기의 인증 획득한 제품에 대하여 소개하고자 한다.

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The Evaluation and Countermeasures for the 2nd Arc Reduction for the High Speed Reclosing in 765kV Transmission Line (765kV 계통의 고속도 다상 재폐로 관련 2차 아크 검토 및 억제 방안)

  • Ahn, J.S.;Kim, J.Y.;Jin, J.Y.
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.613-615
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    • 1995
  • KEPCO is now going on upgrading the highest system voltage from 345kV to 765kV since 1992. The main reason of this 765kV project is the bulk power transmission from the power generation sites at the East and West coasts to the Kyeong-in area. The first 765kV transmission lines will be constructed by 1998 and operated as 345kV level until 2001. This system needs a detailed evaluation of the 2nd arc in case of 765kV transmission line outages and the countermeasures for the fast arc reduction for the successful high speed reclosing. So, this paper deals with the simulation results of the 2nd arc characteristics using EMTP and comparison of Sh.R and HSGS for the reduction methods.

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MULTIPLICITY RESULTS FOR THE WAVE SYSTEM USING THE LINKING THEOREM

  • Nam, Hyewon
    • Korean Journal of Mathematics
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    • v.21 no.2
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    • pp.203-212
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    • 2013
  • We investigate the existence of solutions of the one-dimensional wave system $$u_{tt}-u_{xx}+{\mu}g(u+v)=f(u+v)\;\;in\;(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,\\v_{tt}-v_{xx}+{\nu}g(u+v)=f(u+v)\;\;in\;(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,$$ with Dirichlet boundary condition. We find them by applying linking inequlaities.

Efficient Interference Control Technology for Vehicular Moving Networks

  • Oh, Sung-Min;Lee, Changhee;Lee, Jeong-Hwan;Park, Ae-Soon;Shin, Jae Sheung
    • ETRI Journal
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    • v.37 no.5
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    • pp.867-876
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    • 2015
  • This paper proposes an efficient interference control scheme for vehicular moving networks. The features of the proposed scheme are as follows: radio resources are separated into two resource groups to avoid interference between the cellular and vehicle-to-vehicle (V2V) links; V2V links are able to share the same radio resources for an improvement in the resource efficiency; and vehicles can adaptively adjust their transmission power according to the interference among the V2V links (based on the distributed power control (DPC) scheme derived using the network utility maximization method). The DPC scheme, which is the main feature of the proposed scheme, can improve both the reliability and data rate of a V2V link. Simulation results show that the DPC scheme improves the average signal-to-interference-plus-noise ratio of V2V links by more than 4 dB, and the sum data rate of the V2V links by 15% and 137% compared with conventional schemes.

A Study on the Cultural Characteristics of Pholiota nameko Mycelium (맛버섯 균사체의 배양 특성에 관한 연구)

  • 차월석;이동병;강시형;오동규
    • Journal of Life Science
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    • v.13 no.4
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    • pp.498-504
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    • 2003
  • This Study was carried out to investigate the optimal mycelial growth of Pholiota nameko. The optimal medium for the mycelial growth was ME medium. The optimal temperature and pH were $25^{\circ}C$$\pm$1 and 5.5, respectively. The modified optimal medium compositions were glucose 3% (w/v), malt extract 0.25% (w/v), yeast extract 0.25% (w/v), $KH_2PO_4$ 0.046% (w/v), $K_2HPO_4$ 0.1% (w/v), $MgSO_4$$7H_2O$ 0.05% (w/v). From the result of experiments on the optimal temperature, pH and nutritional requirements, the mycelial growth of modified optimal medium was higher than that of ME medium.