http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
유정열,박명균,박세만 대한안전경영과학회 2004 대한안전경영과학회 학술대회논문집 Vol.2004 No.05
The vertical impact crusher is the machine which could produce artifical sand similar to natural aggregates in the site of guarry and pits. FEM was used to analyse the stress and strength of the machine at high rotational speed. The test specimen was made from the same material as the shaft and tension tests were conducted. The Shaft under extreme conditions was analysed to determine maximum stress level and its location from the results. The maximum level of stress and its location could be predicted.
PSPICE Macromodeling에 의한 PLL의 주파수 특성연구
鄭天錫,朴明烈,金世烈,金洪九 울산대학교 1996 공학연구논문집 Vol.27 No.2
본 논문은 범용화되어있는 Microsim 사의 PSPICE를 이용해서 위상동기루프(PLL) Micromodeling으로 설계하여 시뮬레이션 하였다. PLL 회로는 위상검출기와 전압제어 발진기 그리고 루프 필터로 이루어져 있다. RC 저역통과 필터와 Butterworth 필터 그리고 Chebyshev 필터 등을 이용하여 입력주파수 변화에 따른 루프필터의 주파수 특성을 분석하였다. 그리고 전압제어 발진기의 자주발진주파수를 2.5kHz, 19kHz로 고정할 때의 주파수 스펙트럼을 분석하였다. 자주발진주파수 2.5kHz에서 Chebyshev 필터의 경우 upper lock range와 lower lock range는 똑같이 1,056Hz, 1,056Hz였고 upper capture range와 lower capture range는 536Hz, 540Hz였다. 또한 시뮬레이션 과정에서 삼각파를 구형파로 바꾸는 VCO의 슈미트 트리거단에서 수렴문제로 인하여 19KHz 이상에서는 상당히 긴 시뮬레이션 시간을 필요로 하는 단점이 있었다. 그렇지만 낮은 주파수대에서 주파수 특성 분석의 용이함과 정확성 및 복잡한 회로의 간략화에서 매크로모델링의 타당성을 보였다. With today's general simulator, PSPICE, a phase-locked loop(PLL), which consists of a phase detector(PD), a voltage-controlled oscillator(VCO), and a low-pass filter(LPF), is designed and simulated in macromodeling technique. By using a RC LPF, a Butterworth, and a Chebyshev LPF in turn, the frequency characteristics of the outputs according to the variations of the inputs are analyzed respectively. When 2.5KHz and 19KHz are selected as two specified free running frequencies in VCO block, the frequency spectrums of the outputs show that in case of the Chebyshev LPF at 2.5KHz, the upper and lower rock ranges have the same frequency ranges, 1056Hz, and the upper and lower capture ranges are 536Hz and 540Hz respectively. Furthermore, the simulation takes a long time especially above 19KHz, because of the convergence problem at schmitt trigger section, where the triangular wave is changed into the rectangular wave. However, this paper shows some validity that this macromodeling technique is one of the easy and accurate methods in analyzing the frequency characteristics, and useful in simplifying the complicated circuits at low frequency band below 19KHz.
Comparison of the Energy Estimation Methods for the Neutral Particles in a Nuclear Emulsion Detector
김재률,임인택,박명열 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.3
In a nuclear emulsion detector, studies of the neutron emission from nucleus-nucleus diffractive scattering require energy information on emitted neutrons. An interaction that is produced by a neutral particle in a nuclear emulsion detector is identified by the tracks of the secondary charged particles without any incident particle track. If the emitted neutrons are produced by diffractive scattering, the neutron has almost the same energy as the incident projectile nucleus. The energy of the neutral particles produced by a nucleus-nucleus central collision is distributed according to a certain probability function and is different from the energy of the neutron emitted from diffractive scattering. Therefore, the energies of the neutrons give a way to determine clearly the emission ratio of neutrons from nucleus-nucleus diffractive scattering to neutrons production produced by nucleus-nucleus central collisions clearly.