• 대한기계학회논문집B
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• 제34권7호
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• pp.729-738
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• 2010

질소로 희석된 부탄 층류 부상 화염에서 발생할 수 있는 화염진동 메커니즘을 살펴보기 위하여 실험적 연구를 수행하였다. 화염 진동은 층류 자유제트 부상 화염에서 5가지 영역으로 구분되었다: 화염 안정화 영역 (I), 열손실에 의한 진동 (II), 열손실에 의한 진동과 부력에 의한 진동이 혼재된 영역 (III),열손실에 의한 진동과 화염날림 직전의 진동이 혼재된 영역 (IV), 그리고 열손실에 의한 진동, 부력에 의한 진동 및 화염날림 직전의 진동이 모두 혼재된 영역(V). 각각의 화염진동의 특성을 규명하기 위해 화염의 시간에 따른 부상 높이 변화에 대한 FFT분석을 수행하였고 각 영역에 관련된 무차원 변수와 스트라훌 수의 조합으로 특성화 작업을 수행하였다.

• 대한한의학회지
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• 제16권2호
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• pp.281-298
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• 1995

The following results were made by observation GOT, GPT, ALP, total cholesterol and higlyceride in serum to research the effects of medicines which are Injinsaryungsan(Sample- A) and another medicine(Sample-B) of which Injin(Artemisiae Capillaris Herba)was increased in quantity on liver damaged by $CCl_4$ and d-galactosamine in rats. 1. The high concentrated extracts of Sample A group and Sample- B group showed significant inhibltory effects on the increase of serum GPT, ALP, LDH, total cholesterol and triglyceride levels induced by $CCl_4$ and d-galactosamine. 2. The high concentrated extracts of sample A group and Sample B group showed more significant inhibitory effects(P〈0.001) than the low ones' effects(P〈0.01) on the increase of serum triglyceride level induced by $CCl_4$ 3. Sample-A group showed significant inhibitory effects on the increase of serum GOT, GPT. ALP, total cholesterol and triglyceride levels, but no significance on the increase of serum LDH level induced by d-galactosamine. 4. Sample-B group showed very significant inhibitory effects on the increase of serum GOP, GPT, ALP, LDH, total cholesterol and triglyceride levels induced by d-galactosamine. 5. As compared with Sample-A group, Sample-B group of which Injin was increased in quantity showed more significant inhibitory effects on all items of this experiment induced by $CCl_4$ and d-galactosamine. As mentioned above. it seemed that both Injinsaryungsan and another medicine of which Injin was increased in quantity had effects protecting liver and anti-fatty liver induced by $CCl_4$ and d-galactosamine in rats. Specially Sample-B group had very significant effects on liver damage as compared with Sample-B group. Therefore it seems that more researches on variation according to the increase of Injin dose must be continued for curing liver diseases.

• Journal of the Optical Society of Korea
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• 제2권2호
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• pp.64-73
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• 1998

We have theoretically analyzed and experimentally observed the effects of wavelength dependent birefringence inside a laser cavity on the output characteristics of fiber lasers with a figure eight geometry. The spectral and polarization characteristics of fiber lasers are found to be very susceptible to the resultant birefringence composed of the intrinsically existing wavelength dependent birefringence and the externally induced birefringences inside the fiber. For the variation of twist-induced birefringence inside the nonlinear amplifying loop mirror, the laser output power and center wave-length of continuous wave lasers change periodically, but the polarization characteristics remains nearly unchanged. The changes of the birefringence inside the linear loop has little effect on the spectral characteristics but changes the polarization properties such as the polarization direction.

• Journal of Positioning, Navigation, and Timing
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• 제5권4호
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• pp.173-180
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• 2016

This paper presents a method to suppress multipath induced by pulses using supervised learning. In modern electronics, pulses have been used for various purposes such as communication or distance measurements. Like other signals, pulses also suffer from multipath. When a pulse and a multipath are overlapped, the original pulse shape is distorted. The distorted pulse could result in communication failures or distance measurement errors. However, a large number of samples available from a pulse can be used to effectively reject multipath by using a supervised learning method. This paper introduces how a supervised learning method can be applied to Distance Measuring Equipment. Simulation results show that multipath induced distance measuring error can be suppressed by 10 ~ 45 percent depending on the allowed pulse shape variation allowed in a standard.

• 한국소음진동공학회논문집
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• 제22권1호
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• pp.38-45
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• 2012

In this paper, flow-induced flutter instability of a cantilever carbon nanotube conveying fluid and modelled as a thin-walled beam is investigated. Analytically nonlocal effect, transverse shear and rotary inertia are incorporated in this study. The governing equations and the boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extended Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variation of critical flow velocity of carbon nanopipes based on three different models such as analytically nonlocal model, partially nonlocal model, and local model are investigated and pertinent conclusion is outlined.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.637-640
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• 1991

In this paper deals with linearized control of induction motor by vector control. Output equation induced from d-q axies voltage and current equation of induction moter. The condition of induced equation is that rotor's current of axies has 0 and state current of D axies which was driven by synchronous speed is constant. The fully digital controlled induction motor drive system based on the proposed linearized method and the control circuit of system consists of 16bits micro computer and all the function are implemented with software. When the voltage source inverter control with PI controller is empolyed, in spite of secondary resistance Rr Variation, the Vector control condition is satisfied.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1970-1974
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• 2011

The effects of convection on the measurement of the diffusion coefficients of liquids by the pulsed gradient spin echo (PGSE) NMR method at low temperature are discussed. To examine the generation of convective flows, we used four different types of sample tubes in the diffusion measurements with temperature variation; a normal 5 mm NMR tube, a Shigemi tube, an ELISE type tube, and a capillary tube. Below room temperature, the calculated diffusion coefficients of chloroform in 5 mm o.d. type tubes increased with decreasing temperature, while those in the capillary tube decreased linearly. The convective flow was found to be significant even at low temperature and it seemed to be mainly induced by the transverse temperature gradient. It was also found that the capillary tube was most appropriate to measure the diffusion coefficients, since its small diameter is effective in suppressing the convective flows at both high and low temperatures.

• 전기학회논문지
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• 제67권7호
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• pp.884-891
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• 2018

In this paper, we propose an automatic earthquake P-wave detection algorithm based on the variations of the impact momentum derived from the seismic acceleration signals. The amount of change in the impact momentum induced by the acceleration refers to the influence of buildings or facilities on the earthquake, The proposed algorithm can effectively detect the seismic P-wave by simultaneously considering the amplitude and the frequency change of the seismic wave when the earthquake occurs. Computer simulations using the observed seismic signals were performed to evaluate the validity of the induced impact momentum variation and the superiority of the proposed algorithm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.921-926
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• 2002

In this study, we investigate the plugging effect on the CE type steam generator tube. The natural frequency and mode shape will be changed due to decrease of the effective mass distribution along the tube. We compared the variation of stability ratio for plugged tube with that for unplugged one. The natural frequency increased because of removing the cooling water inside the steam generator tube, but the stability ratio decreased inversely because of changing the vibrational model shape. We also investigated the turbulent excitation effect.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권11호
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• pp.741-746
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• 2004

When investigating a control problem for network based control systems, the main issue is network-induced delay. This delay can degrade the performance of control systems designed without considering the delay and even destabilize the system. In this paper, we consider the stabilization of network based control systems, where there is bounded time-varying delay. This delay is treated like parameter variation of a discrete time system. The state feedback controller design is formulated as linear matrix inequality. Finally, we show that the stability of control systems designed with considering the delay is superior to that is not so.