• Journal of the Korean Mathematical Society
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• v.53 no.4
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• pp.929-967
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• 2016

Let p(t, x) be the fundamental solution to the problem $${\partial}^{\alpha}_tu=-(-{\Delta})^{\beta}u,\;{\alpha}{\in}(0,2),\;{\beta}{\in}(0,{\infty})$$. If ${\alpha},{\beta}{\in}(0,1)$, then the kernel p(t, x) becomes the transition density of a Levy process delayed by an inverse subordinator. In this paper we provide the asymptotic behaviors and sharp upper bounds of p(t, x) and its space and time fractional derivatives $$D^n_x(-{\Delta}_x)^{\gamma}D^{\sigma}_tI^{\delta}_tp(t,x),\;{\forall}n{\in}{\mathbb{Z}}_+,\;{\gamma}{\in}[0,{\beta}],\;{\sigma},{\delta}{\in}[0,{\infty})$$, where $D^n_x$ x is a partial derivative of order n with respect to x, $(-{\Delta}_x)^{\gamma}$ is a fractional Laplace operator and $D^{\sigma}_t$ and $I^{\delta}_t$ are Riemann-Liouville fractional derivative and integral respectively.

• Journal of the Korean institute of surface engineering
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• v.21 no.4
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• pp.160-167
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• 1988

Electrochemical behaviors od chromium electrodeposition from 0.05M chromium (III) sulface complexes in aqueous solutions using sodium formate-glycine mixtures as a complexing agent were studied. In the cathodic current-potential cures, it is found that the intial limiting current of Cr(III) is proportional to square root of scan rate and activiation energy from Arrhenius plot is s obtained 3.05Kcal/mol. From this results, the reaction is considered, Cr3++e longrightarrow Cr2+, which is controlled diffusion of Cr (III). It is also found that the chromium is deposited when the potential reaches to hydrogen evolution potential. Effects of NaSCN as a catalyser in the electrolyte were investigated NCS- anion seems to react strongly by specific absorption at the inner HelmholtZ layer, so that, it is considered to suppress the electrodeposition reaction reaction for chromjum, and also it is considered multipe-bridge such as Cr(III)-NCS---M(M;cathode).

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.381-388
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• 1994

A new process which co-fires the low-firing-substrate and copper conductor was studied to achieve good bond strength and low sheet resistance of conductor. Cupric oxide is used as the precursor of conductive material in the new method and the firing atmosphere of the new process is changed sequently in air H2N2. The addition of cupric oxide and variations of firing atmosphere permited complete binder-burnout in comparison with the conventional method and contributed to the improvement of resistance and bonding behaviors. The potimum conditions of this experiment to obtain the satisfactory resistance and bond strength are as follows (binder-burnout temperature in air; 55$0^{\circ}C$, reducing temperature in H2; 40$0^{\circ}C$ for 30 min, ratio of copper and cupric oxide; 60:40~30:70 wt%). The bonding mechanism between the substrate and metal was explained by metal diffusion layer in the interface and the bond strength mainly depended on the stress caused by the difference of shrinkage and thermal expansion coefficient between the substrate and metal.

• The Pure and Applied Mathematics
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• v.16 no.4
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• pp.427-441
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• 2009

The method of Lattice Dynamical System is used to establish a global model on an infinite chain of many local markets interacting each other through a diffusion of prices between them. This global model extends the Walrasian evolutionary cobweb model in an independent single local market to the global market evolution. We assume that each local market has linear decreasing demands and quadratic supplies with naive predictors, and investigate the stationary behaviors of global price dynamics and show that their dynamics are conjugate to those of $H{\acute{e}}non$ maps and hence can exhibit complicated behaviors such as period-doubling bifurcations, chaos, and homoclic orbits etc.

• The Pure and Applied Mathematics
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• v.17 no.1
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• pp.93-106
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• 2010

We employ the methods of Lattice Dynamical System to establish a global model extending the Walrasian evolutionary cobweb model in an independent single local market to the global market evolution over an infinite chain of many local markets with interaction of each other through a diffusion of prices between them. For brevity of the model, we assume linear decreasing demands and logistic supplies with naive predictors, and investigate the traveling wave behaviors of global price dynamics and show that their dynamics are conjugate to those of H$\acute{e}$non maps and hence can exhibit complicated behaviors such as period-doubling bifurcations, chaos, and homoclic orbits etc.

• Asia pacific journal of information systems
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• v.23 no.2
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• pp.87-109
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• 2013

While many surveys show very positive attitudes on the part of consumers towards eco-friendly products, the market share actually reflecting green IT purchases remains low in most countries. The motivations behind green IT purchase behavior are still obscure. Several studies have addressed the question of green IT diffusion from economic and normative viewpoints in an attempt to interpret IT adoption behavior. This study comes at the question from a different angle, namely negative frame, examining threat and coping behaviors using the Ordered Protection Motivation (OPM) model and threat appraisal theory. The results show that attitudes toward fairness and positive change, which are precedents of threat appraisal, play an important role in determining threat appraisal. Perceived threats in the green IT arena include habit change and ecological change. Appraisal for coping with these threats directly affects initial adoption behaviors regarding available green IT, and then indirectly encourages the purchase of new green IT products.

• Bulletin of the Korean Chemical Society
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• v.10 no.3
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• pp.258-261
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• 1989

The electrochemical behaviors of 4-(2)-thiazolylazo)-resorcinol (TAR) in acetonitrile solution was studied by DC polarography, cyclic voltammetry, controlled-potential coulometry and UV-Vis spectroscopy. The electrochemical reduction of TAR occurs in four-one electron reduction steps in acetonitrile solution. The products of the first and the third electron transfer are speculated to be a relatively stable anion radical. The second electron transfer to the dianion is followed by a chemical reaction producing a protonated species. The product of the fourth electron transfer also produces the corresponding amine compounds with a following reaction. Also every reduction wave was diffusion controlled. The first reduction wave is considerably reversible and the other waves are less reversible.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.84-90
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• 2015

Titanium alloys has been received an attention due to their excellent specific strength and many other superior properties in the application of components of flying subjects. In this study, Ti-6Al-4V (Ti64 alloy) has been selected in order to evaluate oxidation and degradation behaviors under the exposure of high temperature flame. The alloy has been coated with Al diffusion coating routes. The coated alloys showed an improved oxidation and degradation behaviors. The oxidation and degradation mechanism for the coated and uncoated alloys has been discussed in terms of microstructural observations.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.43-45
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• 2003

The empirical model for predicting the prior austenite grain size in low-alloy steel weld HAZ was developed through examining the effect of alloying element. The test alloys were made by vacuum induction melting. Grain growth behaviors were observed and analyzed by isothermal grain growth test and subsequent metallography. As a result, it was found that the grain growth might be controlled by grain boundary diffusion and the empirical model for grain growth was presented.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.58-59
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• 2002

고밀도 자기기록 매체의 재생 헤드로 응용되기 위해서는 높은 자기 저항비와 소자 제조 및 작동시 발생되어지는 열에 대해서 안정해야한다. 일반적으로 스핀밸브에서 나타나는 열화현상 중 가장 주된 원인은 반강자성체에 사용된 Mn이 고정층 및 비자성층으로의 확산으로 인해 반강자성체/강자성체 산이의 교환결합력의 감소와 스핀의존산란이 감소되어 자기적 특성이 열화 되는 것이다[1]. 이러한 상호확산은 거칠기, 결정성, 결정립 크기와 같은 미세구조에 크게 의존한다[2]. (중략)