http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Seongeun Lee,Byunggwan Lee,Jinwook Choi,정용수,오한준,지충수 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.3
Poly(vinylidene fluoride) nanotubes were fabricated by using solution wetting methods with nanoscale AAO templates whose pore diameters were about 90 nm and 190 nm when prepared by anodizing in oxalic-/and phosphoric-acid solutions, respectively. Wetting of the AAO template was done under two conditions of heat treatments, annealing at 200℃ and then cooling to 130℃ and annealing for 1 h at 130℃ after having been kept at room temperatures. The synthesis of nanowires and nantubes was particularly affected by the annealing condition. The attenuated total reflectance (ATR) spectroscopy result suggested that the PVDF nanotubes crystallized exclusively in the α form while the nanowires formed in a mixture of α and γ phases. These results indicate that the morphology and the crystallization of the PVDF nanostructures are affected by the annealing time and temperature and by the solution wetting conditions. X-ray diffraction (XRD) patterns with a relatively high intensity at the (020) plane showed that a texture is induced in α-PVDF nanotubes when a wetting solution of 10 wt% PVDF in DMF is used.
Synthesis of Silver Nanowire Arrays by Thermal Decomposition of Silver Acetate
Seongeun Lee,오한준,이준희,이오연,지충수,정용수 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.4
Rapid progress in nanotechnology has made it increasingly easier to nanostructure metal materials. This paper describes the formation of uniform silver nanowires by reducing silver acetate with PLLA polymer. The silver nanowires were prepared by wetting a porous template at 350 °C using 1.5 wt.% CH2Cl2 solution containing PLLA/silver acetate in a ratio of 1:1. A thermal analysis in the temperature range of 100 °C to 400 °C was carried out by a differential scanning calorimeter (DSC). An exothermic reaction peak associated with pure silver occurred at 352 °C at a heating rate of 5 °C/min. From the attenuated total reflectance (ATR) spectra analysis of the silver and PLLA composites, it was obtained that the absorption peak of the PLLA became weak by heating to successively higher temperatures in the range of 230 °C to 350 °C. The DSC and ATR results showed that the PLLA can be directly and easily removed at 350 °C, leaving the pure metal inside the pores. The silver nanowires consisted of nanoparticles whose average diameter was about 26.5 nm. And those nanowires with an aspect ratio of about 13 showed an UV-vis absorption peak, which is attributed to the surface plasmon excitation at 350 nm and 377 nm. Rapid progress in nanotechnology has made it increasingly easier to nanostructure metal materials. This paper describes the formation of uniform silver nanowires by reducing silver acetate with PLLA polymer. The silver nanowires were prepared by wetting a porous template at 350 °C using 1.5 wt.% CH2Cl2 solution containing PLLA/silver acetate in a ratio of 1:1. A thermal analysis in the temperature range of 100 °C to 400 °C was carried out by a differential scanning calorimeter (DSC). An exothermic reaction peak associated with pure silver occurred at 352 °C at a heating rate of 5 °C/min. From the attenuated total reflectance (ATR) spectra analysis of the silver and PLLA composites, it was obtained that the absorption peak of the PLLA became weak by heating to successively higher temperatures in the range of 230 °C to 350 °C. The DSC and ATR results showed that the PLLA can be directly and easily removed at 350 °C, leaving the pure metal inside the pores. The silver nanowires consisted of nanoparticles whose average diameter was about 26.5 nm. And those nanowires with an aspect ratio of about 13 showed an UV-vis absorption peak, which is attributed to the surface plasmon excitation at 350 nm and 377 nm.
토크 컨버터 댐퍼 시스템 다단화를 통한 진동특성 최적화
이성은(Seongeun Lee),최완(Wan Choi),장재덕(Jaeduk Jang),주인식(Insik Joo) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
Recently, in order to improve the fuel economy in vehicle, it has been tried to lower torque converter lock-up speed and the vehicle’ engine is composed of direct injection, variable compression ratio, variable engine displacement, cylinder deactivation, homogeneous charge compression ignition, turbo charger and high pressure fuel injection. Accordingly, this trend is likely to cause the abnormal vibration accompanied by the vehicle vibration. To overcome disadvantageous vibration characteristic , Several type of advance damper system have been developed and the existing damper system have been optimized with the multi-stage damper system. The torsional vibration in the research is analyzed by the vehicle power train model using AMESim that is a commonly used program for analyzing vehicle dynamic characteristics. In this research, it is focused on developing that the vehicle vibration characteristic is optimized by the damper system with the multi-stage.
이성은(SeongEun Lee),최완(Wan Choi),장재덕(JaeDuk Jang),주인식(InSik Joo) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Recently, in order to improve the fuel economy in vehicle, it has been tried to lower torque converter lock-up speed in automatic transmission. But this trend is likely to cause the abnormal vibration and surge accompanied by the vehicle vibration during a drive. The torsional vibration characteristics by many researchers were investigated on the NVH issues. but so far to comprehend the vibration characteristics of the vehicle power train system has so difficulty doing. So, the torsional vibration analysis of the vehicle is investigated by the vehicle power train modeling using AMESim<SUP>®</SUP> that is a commonly used program for analyzing vehicle dynamics characteristics. The vehicle power train model shows the torque fluctuation of vehicle caused by changing torque converter’s primary inertia, secondary inertia, stiffness and hysteresis of damper. Additionally, this paper presents a guideline for the torque converter design to minimize the torsional vibration in power train of automatic transmission vehicle.
전자형 댐퍼 적용을 통한 차량 비틀림 진동 절연 특성 최적화
이성은(Seongeun Lee),김진문(Jinmoon Kim),장재덕(Jaeduk Jang),주인식(Insik Joo) 한국자동차공학회 2013 한국자동차공학회 지부 학술대회 논문집 Vol.2013 No.4
Torque converter is located between the engine and automatic transmission and transfers power to the automatic transmission from the engine. Under opened condition of lock-up clutch, the power is transferred to the transmission by ATF(automatic transmission fluid) and under closed condition of lock-up clutch, torsional vibration is damped by damper system. Recently, in order to improve the fuel economy in vehicle, it has been tried to lower torque converter lock-up speed and internal combustion engine is composed of the latest technology with direct injection, variable compression ratio, variable engine displacement, cylinder deactivation. Accordingly, this trend is likely to cause the abnormal vibration accompanied by the vehicle vibration. To overcome disadvantageous vibration characteristics, Several type of advance damper system have been developed. This research did an analysis of the vehicle power train model using Simulation X<SUP>®</SUP> that is a commonly used program for analyzing vehicle dynamic characteristics. it is focused on developing that the vehicle vibration characteristic is optimized by the damper system with pendulum damper.