• Journal of Integrative Natural Science
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• v.1 no.1
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• pp.36-40
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• 2008

본 논문은 자바 에플릿(Java applet)을 이용하여 보존모형과 비보존모형의 온도에 따른 손상확산(damage spreading)의 특성을 분석하였다. 보존모형인 아이징(Ising)모형과 비보존 모형인 격자기체(lattice gas) 및 Driven Diffusive System(DDS)을 다양한 전이확률(transition probability)을 사용하여 온도에 따라 물질내부에서 손상확산이 어떻게 발전하는지를 자바 에플릿 프로그램을 이용하여 시각화하여 손상확산을 명확히 이해하고자 하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.87-92
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• 2016

Van der Pol's oscillators is non-conservative oscillator that having nonlinear damping phenomena. The energy of its system is dissipative at a high amplitude whereas its system creates the energy at low amplitude. In order to identify another behaviors in the Van der Pol oscillator, the periodic external force applied in the Van der Pol oscillator. This paper confirms the pattern of variation for the limit cycle according to parameter variation in order to identify another behaviors in the Van der Pol oscillator.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.191-196
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• 2016

Van der Pol's oscillators is non-conservative oscillator that having nonlinear damping phenomena. The energy of its system is dissipative at a high amplitude whereas its system creates the energy at low amplitude. This paper deals with the Van der Pol oscillator model with a fractional order when the external force apply into Van der Pol oscillator. This paper confirms the status of variation for the limit cycle according to the parameter variation of fractional order in the Van der Pol oscillator that can be represented by fractional differential equation.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.33-42
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• 2000

Adsorption onto the surfaces of solid particles is a well known phenomenon that causes the retardation effect of heavy metals in soils. For adequate remediation of soil and groundwater contamination, it is important to investigate the mobility of heavy metals that largely depends on pH conditions in the soil water since adsorption of heavy metals is pH-dependent. In this study, we investigated the transport of Zn ion under various pH conditions in a sandy soil by conducting batch and column tests. The batch test was performed using the standard procedure of equilibrating fine fractions collected from the soil with eleven different initial $ZnCl_2$ concentrations, and analysis of Zn ion in the equilibrated solutions using ICP-AES. The column test consisted of monitoring the concentrations of soil solutions exiting the soil column with time known as a breakthrough curve (BTC). We injected respectively $ZnCl_2$ and KCl solutions with the concentration of 10 g/L as a tracer in a square pulse type under three different pH conditions (7.7, 5.8, 4.1) and monitored the flux concentration at the exit boundary using an EC meter and ICP-AES. The resident concentration was also monitored at the 10cm-depth by Time Domain Reflectometry (TDR). The results of batch test showed that ion exchange process between Zn and other cations (Ca, Mg) was predominant. The retardation coefficients obtained from adsorption isotherms (Linear, Freundlich, Langmuir) resulted in the various values ranging from 1.2 to 614.1. No retardation effect but ion exchange was found for the BTCs under all pH conditions. This can be explained by the absence of other cations to desorb Zn ion from soil exchange sites under the conditions of ETC experiment imposing blank water as leachate in steady-state flow. As pH decreased, the peak concentration of Zn increased due to the competition of Zn with hydrogen ions ($H^+$) and the concentrations of other cations decreased. The peak concentration of Zn was increased by 12.7 times as pH decreased from 7.7 to 4.1.