http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
방향성 강판을 적용한 전기자동차용 매입형 영구자석 동기전동기 설계
서현욱,임동국,권민수 대한전기학회 2022 전기학회논문지 Vol.71 No.7
In this paper, the interior permanent magnet synchronous motor (IPMSM) for electric vehicles (EVs) using grain-oriented electrical steel (GO) is proposed. It was confirmed through the B-H characteristic curve and the B-W characteristic curve that the GO has superior magnetic characteristic compared to the non-grain-oriented electrical steel (NO). In order to maximize the effect of GO, the GO was partially applied to the stator teeth that has a uniform magnetic flux direction through magnetic path analysis of the EV traction motor. It has been confirmed that the output and various characteristics of the motor have improved with the application of GO. In particular, the iron loss was decreased by 44.83% in no-load condition. Moreover, the average torque and the efficiency were increased by 5.26%, 0.29%, respectively and the iron loss was decreased by 42.45% in load condition. The result of this study shows that the partial application of the GO in IPMSM improves the performance of the motor, effectively.
서현욱,김영독,김광대,정명근,최강호,홍은미,이규환,임동찬 한국고분자학회 2012 Macromolecular Research Vol.20 No.2
We prepared nanostructured carbon fiber surfaces using chemical vapor deposition in which Ni nanoparticles were used as carbon nanostructure growth catalysts. The surface of the nanostructured carbon fiber was covered by a thin polydimethylsiloxane film. This surface showed superhydrophobic behavior with a water contact angle close to 170 °C, and its superhydrophobicity was sustained in a wide pH range (1-13).
CO Oxidation of Catalytic Filters Consisting of Ni Nanoparticles on Carbon Fiber
서현욱,남종원,김광대,김영독,임동찬 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.4
Catalytic filters consisting of Ni nanoparticle and carbon fiber with different oxidation states of Ni (either metallic or oxidic) were prepared using a chemical vapor deposition process and various post-annealing steps. CO oxidation reactivity of each sample was evaluated using a batch type quartz reactor with a gas mixture of CO (500 mtorr) and O2 (3 torr) at 300 oC. Metallic and oxidic Ni showed almost the same CO oxidation reactivity. Moreover, the CO oxidation reactivity of metallic sample remained unchanged in the subsequently performed second reaction experiment. We suggested that metallic Ni transformed into oxidic state at the initial stage of the exposure to the reactant gas mixture, and Ni-oxide was catalytically active species. In addition, we found that CO oxidation reactivity of Ni-oxide surface was enhanced by increase in the H2O impurity in the reactor.
Interaction of TiO2 Films on Carbon Fibers with Toluene
서현욱,김광대,Yuan Luo,Myoung Joo Kim,Nilay Kumar Dey,Young Dok Kim 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.8
TiO2 thin films were synthesized on carbon fibers using chemical vapor deposition. We show that these films can exhibit extraordinarily high absorption capacities of toluene vapor. Such an absorption phenomenon of toluene at room temperature was not found for other TiO2 samples. Upon toluene absorption change in the color (darkening) of the film was found, indicating that these films can be used as an indicator of the existence of volatile organic compounds in the indoor environments. By X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM), a high concentration of OH species and a unique layered structure were found for the TiO2 films and these could be related to their high absorption capacity of toluene.
서현욱,정명근,김광대,김영독,임동찬,이규환 한국물리학회 2013 Current Applied Physics Vol.13 No.1
Polydimethylsiloxane (PDMS) thin films were deposited on Ni particles with a mean size of w1 mm using chemical vapor deposition method. The thin films consisting of these PDMS-covered Ni particles showed a water contact angle higher than 160, corresponding to the superhydrophobicity. These superhydrophobic films were found to be resistant toward acidic and basic media. The PDMS-covered Ni particles showed high affinity toward non-polar organic solvent such as toluene. Together with an external magnetic field, the PDMS-covered Ni can be used for separating water and toluene from a water/ toluene heterogeneous mixture.
서현욱,김민영,한소엽,엄익환 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.7
Second-order rate constants (kN3−) for SNAr reactions of 1-(Y-substituted-phenoxy)-2,4-dinitrobenzenes (2a–2h) with N3− in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C have been measured spectrophotometrically. The Brønsted-type plot is linear with βlg = −0.38. The Hammett plots correlated with σYo and σY− constants exhibit highly scattered points. In contrast, the Yukawa–Tsuno plot results in an excellent linear correlation with ρY = 1.02 and r = 0.51, indicating that a negative charge develops partially on the O atom of the leaving Y-substituted-phenoxy moiety in the transition state. Accordingly, the reactions have been concluded to proceed through a stepwise mechanism, in which expulsion of the leaving group occurs in the rate-determining step. Comparison of kN3− with the kOH− values reported previously for the corresponding reactions with OH− has revealed that N3− is only 6- to 26-fold less reactive than OH− toward substrates 2a–2h, although the former is over 11 pKa units less basic than the latter. Solvation and polarizability effects have been suggested to be responsible for the unusual reactivity shown by N3− and OH−. Effects of changing nucleophile from OH− to N3− on reaction mechanism and reactivity are discussed in detail.
소형펀치 시험법을 이용한 INCONEL Alloy 617의 수소취화거동 평가
서현욱,마영화,윤기봉 한국수소및신에너지학회 2010 한국수소 및 신에너지학회논문집 Vol.21 No.4
For the conversion into hydrogen society, not only studying facilities of hydrogen production, storage, transportation and charging system but also developing technique of ensuring safety are essentially needed. Hence, for the first step of that, evaluated the hydrogen embrittlement of Inconel alloy 617, Ni-based super heat-resisting alloy, by small punch test. Prepared the various specimens through changing electrochemical charging time and measured the toughness degradation of the specimens by small-punch test. The analysis of hydrogen embrittlement behavior were carried out by investigating the fractured surface of specimens. This study has significance on revealing mechanism of hydrogen embrittlement behavior and the factor affecting hydrogen embrittlement in the future study.