• Bulletin of the Korean Chemical Society
• /
• 제22권3호
• /
• pp.271-275
• /
• 2001

We investigated H-type molecular aggregation in a simply spin-coated amorphous homopolymer film of polymethacrylate containing push-pull azobenzene moieties. It was found that the aggregate formation was strongly influenced by thermal treatment an d that the aggregate created in the polymer film could be easily disrupted by irradiation of a linearly polarized light. In the first writing cycle of aggregated polymer film, photo-induced birefringence showed a steep increase to the highest value followed by a gradual decrease to the certain asymptotic value under longer irradiation of a linearly polarized light. This unique behavior could be attributed to the cooperative motion and the disruption of the aggregated molecules under continuous irradiation of light.

• 대한수학회지
• /
• 제58권4호
• /
• pp.873-894
• /
• 2021

In this paper, we consider the Gudnason model of 𝒩 = 2 supersymmetric field theory, where the gauge field dynamics is governed by two Chern-Simons terms. Recently, it was shown by Han et al. that for a prescribed configuration of vortex points, there exist at least two distinct solutions for the Gudnason model in a flat two-torus, where a sufficient condition was obtained for the existence. Furthermore, one of these solutions has the asymptotic behavior of topological type. In this paper, we prove that such doubly periodic topological solutions are uniquely determined by the location of their vortex points in a weak-coupling regime.

• Nonlinear Functional Analysis and Applications
• /
• 제28권1호
• /
• pp.57-79
• /
• 2023

We investigate the existence and uniform attractivity of solutions of a class of functional integral equations which contain a number of classical nonlinear integral equations as special cases. Using the technique of measures of noncompactness and a fixed point theorem of Darbo type we prove the existence of solutions of these equations in the Banach space of continuous and bounded functions on the nonnegative real half axis. Our results extend and improve some known results in the recent literature. An example illustrating the main result is presented in the last section.

• 대한수학회지
• /
• 제61권4호
• /
• pp.797-836
• /
• 2024

We consider the following strongly damped wave equation on ℝ³ with memory u_tt - αΔu_t - βΔu + λu - ∫₀^∞ κ'(s)∆u(t - s)ds + f(x, u) + g(x, u_t) = h, where a quite general memory kernel and the nonlinearity f exhibit a critical growth. Existence, uniqueness and continuous dependence results are provided as well as the existence of regular global and exponential attractors of finite fractal dimension.

• 대한수학회지
• /
• 제61권2호
• /
• pp.227-253
• /
• 2024

This paper studies the existence of weak solutions and the stability of stationary solutions to stochastic 3D globally modified Navier-Stokes equations with unbounded delays in the phase space BCL_-∞(H). We first prove the existence and uniqueness of weak solutions by using the classical technique of Galerkin approximations. Then we study stability properties of stationary solutions by using several approach methods. In the case of proportional delays, some sufficient conditions ensuring the polynomial stability in both mean square and almost sure senses will be provided.

• 응용통계연구
• /
• 제31권2호
• /
• pp.287-301
• /
• 2018

0이 과도하게 많이 나타나는 자료는 여러 다양한 분야에서 흔히 볼 수 있다. 이러한 자료들을 분석할 때 대표적으로 영과잉 포아송 모형이 사용된다. 특히 반응변수들 사이에 상관관계가 존재할 때에는 랜덤효과를 영과잉 포아송 모형에 도입해서 분석해야 한다. 이러한 모형은 주로 빈도론자들의 접근방법으로 분석되어왔는데, 최근에는 베이지안 기법을 사용한 분석도 다양하게 발전되어 왔다. 본 논문에서는 반응변수들 사이에 상관관계가 존재하는 경우 랜덤효과가 포함된 영과잉 포아송 회귀모형을 베이지안 추론 방법을 토대로 제안하였다. 이 모형의 적합성을 판단하기 위해 모의 실험을 통해 랜덤효과를 고려하지 않은 모형과 비교 분석하였다. 또한, 실제 지역사회 건강조사 흡연 자료에 직접 응용하여 그 결과를 살펴보았다.

• 한국가시화정보학회지
• /
• 제15권2호
• /
• pp.48-58
• /
• 2017

To analyze bubbles generated by an ABB (Air Bubble Barrier), we developed image processing procedure and statistical analysis method. Air was discharged from 5 mm nozzle as swarm form at the bottom of 1 m3 water tank. Flow rates of discharged air are ranged from 2 L/min to 20 L/min and these are corresponding to Reynolds number of 1766-17663. Rise velocity of bubble is extracted by using image process pretending intrusive method. Mean equivalent velocity was calculated using void fraction weighting factor. Bubble diameter is obtained and compared with correlations in the literature. Also, we present a correlation according to the result of this study. Mean velocity and mean diameter of bubbles increase with increasing gas Reynolds number. But these parameters show an asymptotic trend when they approach to high Reynolds number.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권11호
• /
• pp.5370-5393
• /
• 2019

In this paper, we consider a two-way relay non-orthogonal multiple access (TWR-NOMA) system with residual hardware impairments (RHIs) and channel estimation errors (CEEs), where two group users exchange their information via the decode-and-forward (DF) relay by using NOMA protocol. To evaluate the performance of the considered system, exact analytical expressions for the outage probability of the two groups users are derived in closed-form. Moreover, the asymptotic outage behavior in the high signal-to-noise ratio (SNR) regime is examined and the diversity order is derived and discussed. Numerical simulation results verify the accuracy of theoretical analyses, and show that: i) RHIs and CEEs have a deleterious effects on the outage probabilities; ii) CEEs have significant effects on the performance of the near user; iii) Due to the RHIs, CEEs, inter-group interference and intra-group interference, there exists error floors for the outage probability.

• Structural Engineering and Mechanics
• /
• 제35권2호
• /
• pp.191-203
• /
• 2010

To investigate the critical buckling load and post-buckling behavior of an axially loaded pile entirely embedded in soil, the non-linear large deflection differential equation for a pinned pile, based on the Winkler-model and the discretionary distribution function of the foundation coefficient along pile shaft, was established by energy method. Assuming that the deflection function was a power series of some perturbation parameter according to the boundary condition and load in the pile, the non-linear large deflection differential equation was transformed to a series of linear differential equations by using perturbation approach. By taking the perturbation parameter at middle deflection, the higher-order asymptotic solution of load-deflection was then found. Effect of ratios of soil depth to pile length, and ratios of pile stiffness to soil stiffness on the critical buckling load and performance of piles (entirely embedded and partially embedded) after flexural buckling were analyzed. Results show that the buckling load capacity increases as the ratios of pile stiffness to soil stiffness increasing. The pile performance will be more stable when ratios of soil depth to pile length, and soil stiffness to pile stiffness decrease.

• 한국통신학회논문지
• /
• 제31권12C호
• /
• pp.1150-1156
• /
• 2006

본 논문에서는 $M\geq3$이고 $p\equiv{\pm}1$ mod M인 경우에 대해서 주기가 $p^m-1$인 M진 Sidel'nikov 수열의 $F_p$ 상에서의 선형복잡도의 하계와 1-오류 선형복잡도의 상계를 유도한다. 특히 $m\geq4$이고 $p\equiv-1$ mod 3인 경우에는 3진 Sidel'nikov 수열의 정확한 1-오류 선형복잡도를 계산한다. 이 결과들을 바탕으로 선형복잡도와 1-오류 선형복잡도의 주기에 대한 비율의 근사적 특성을 제시한다.