Epitaxial Layer-by-Layer Propagation of a Patterned Surface

이상법 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.III

The propagation of a patterned surface during epitaxial growth is studied by using kinetic Monte Carlo simulations. Starting with a nanostructured substrate, the pattern re-emerges after every layer, but, as growth proceeds, errors accumulate so that the pattern has a finite lifetime. The lifetime of a pattern first increases with the diffusion-to-deposition ratio as $(D/F)^{0.2}$ but then saturates to a finite value for large $D/F$ if there is sufficient diffusion along the island edges leading to compact islands. In the absence of edge diffusion, the submonolayer islands are fractal. Then, the pattern lifetime keeps increasing beyond the initial power-law dependence on $D/F$, but with a decreasing effective exponent. The lifetime also depends on the characteristic pattern size. For checkerboard patterns, the size dependence of the optimal $D/F$, for which the lifetime is longest, is analyzed.

과학영재 선발 문항 성취도의 지역별 편차에 관한 연구

이상법 한국과학교육학회 2001 한국과학교육학회지 Vol.21 No.1

경북대학교 과학영재교육센터에서 선발에 사용한 문항이 과학영재교육 대상 학생의 선발에 적절하였는지의 여부를 분석하고, 같은 문항을 교육환경이 다른 시골, 중소도시 및 대도시의 세 지역의 중학교 3학년 학생에게 적용하여 영재아 선발이 지역별로 각기 다른 교육 환경에 따라서 차이를 보일 수 있는지의 여부를 분석하였다. 먼저, 경북대학교 과학영재교육센터 선발에 응시한 407명의 검사 결과로부터 문항의 난이도 및 변별도를 계산한 결과 대부분의 문항이 난이도나 변별도 중 둘 모두 또는 어느 하나에서 적절하다고 알려진 범주 내에 속함을 알 수 있었다. 같은 문항을 교육 환경이 다른 세 지역의 학생들에게 적용한 결과, 유의수준 0.05 이내에서 성취도에 유의미한 차이가 없었다. 이러한 사실은 경북대학교 센터에서 사용한 검사도구는 교육 환경의 차이나 학교 외의 교육을 통한 선행학습 여부에는 그다지 영향을 받지 않음을 의미한다. 또, 경북대학교 과학영재교육센터에 선발된 학생들의 학력은 중학교 3학년 학생들의 학력에 비해 과학적 사고능력은 상위 10%이내, 어휘력은 상위 20%이내에 속하는 학생들임을 알 수 있었다. We study the adequacy of the admission test used at the Science Education Center for Gifted Youth, Kyungpook National University (KNU SECGY). We first analyze the test problems of scientific thinking skill and vocabulary employed to select the gifted students at SECGY. We then apply the same tools to the sampled third-grade male and female middle-school students in three different regions with different educational environments, i.e., in the large city, in the middle city, and in the rural region. We find that the indices of difficulty and the indices of discrimination of the most of the problems used at SECGY fall in the appropriate ranges, implying that the tools are adequate to select the gifted youth among the recommended excellent students. The results of the sampled students are found not to depend much upon the educational environments within the significance level of 5%, except the group of female students in the middle city, for which the samples appear to be biased due to the special circumstances at the time of the study. We finally find that all selected students at the SECGY appear to possess the giftedness in the scientific thinking skills, and to belong to within the top 10% of the third grade students. However, the results of the vocabularies do not appear to fall into the same range.

퍼콜레이션 감수율의 진폭비의 보편성

이상법 경북대학교 과학교육연구소 1997 科學敎育硏究誌 Vol.21 No.-

We study the universality of two off-lattice percolation models, i.e., the continuum percolation of randomly centered disks and spheres for penetrable concentric shell(PCS) model and the randomly bonded percolation of uniformly distributed points, and also of the irreversible kinetic gelation model. We specifically consider the amplitude ratio of percolation susceptibilities R=C_-/C_+ (C_- and C_+ being the amplitudes below and above the percolation susceptibilities which is supposed to be universal but found to be different from the ordinary lattice percolation values in both two and three dimensions. By numerical investigation, we find that R depends strongly on the size of system for the former two off-lattice percolation models; after a finite size effect is carefully taken into account, R is found to be consistent with the known lattice value, indicating a strong universality between lattice and off-lattice percolation models. For the kinetic gelation model, on the other hand, we find that R does not depend strongly upon the size of system and is close to the lattice value, again indicating a strong universality between these two models. We point out that the primary cause of such differences may be the different (approximate) sampling techniques for the percolation susceptibilities. We discuss some subtleties of finite size scaling analyses.

양호한 회복을 보인 일본B형뇌염 환자 증례; 임상경과, 영상소견 및 신경심리검사 결과

이상법,석정임,김준우 대한신경과학회 2015 대한신경과학회지 Vol.33 No.2

Initial-state Dependence of the Critical Behavior in the Conserved Lattice Gas Model in One Dimension

이상법 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.11

The conserved lattice gas model in one dimension, generated from various initial states, wasintensively studied. The dynamic critical exponents and k associated with the decay of activeparticledensities and the correlation time, respectively, were found to depend drastically on theinitial states. The perfectly-ordered initial state prepared by repeatedly placing the block ‘0011’yielded a standard critical behavior, with the critical exponents satisfying all the scaling relations. On the other hand, the natural initial states and the ordered initial states of blocks of odd numbersof particles yielded an exponent slightly larger than that of an ordered state of ‘0011’, but thedata for active-particle densities did not satisfy scaling function. The exponents and k were alsocalculated from, respectively, the autocorrelation function and the persistence distribution of theactive-particle densities, both in the steady states. The value of was found to be close to thevalue for an ordered state of ‘0011’ whereas the value of k was consistent with that for the randominitial states.

Critical Exponents of the Absorbing Phase Transition in the Conserved Threshold Transfer Process in One Dimension

이상법 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

The critical exponents of the absorbing phase transition in a conserved threshold transfer process were measured via Monte Carlo simulations. The exponents θ and β, characterizing, respectively, the density of active particles in time and the order parameter against the distance from criticality, were found to be θ = 0.118 ± 0.003 and β = 0.396 ± 0.015, respectively. The correlation-time exponent νⅡ and the dynamic exponent z were estimated, respectively, as νⅡ 3.36 and z 1.49 from the off-critical scaling and the finite-size scaling analyses using the all-sample averages of the active-site density. The scaling relations β = νⅡθ and z = νⅡ/ν⊥ were satisfied with the measured exponents, and the latter two exponents were found to be considerably different from the previouslyreported results. The critical exponents of the absorbing phase transition in a conserved threshold transfer process were measured via Monte Carlo simulations. The exponents θ and β, characterizing, respectively, the density of active particles in time and the order parameter against the distance from criticality, were found to be θ = 0.118 ± 0.003 and β = 0.396 ± 0.015, respectively. The correlation-time exponent νⅡ and the dynamic exponent z were estimated, respectively, as νⅡ 3.36 and z 1.49 from the off-critical scaling and the finite-size scaling analyses using the all-sample averages of the active-site density. The scaling relations β = νⅡθ and z = νⅡ/ν⊥ were satisfied with the measured exponents, and the latter two exponents were found to be considerably different from the previouslyreported results.

Restricted Solid-on-solid Growth Model for Fractal Substrates

이상법,정형채,김진민 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.5

A restricted solid-on-solid growth model is studied for various fractal substrates, i.e., a Sierpinski gasket, a checkerboard fractal, and a Sierpinski carpet, all embedded in two dimensions. The interface width W grows as t^β with β≈ 0.29 for Sierpinski gasket and β≈ 0.31 for both a checkerboard fractal and a Sierpinski carpet. At saturation, W follows W ∼ L^α, with α≈ 0.50 for a Sierpinski gasket and α≈ 0.52 for both a checkerboard fractal and a Sierpinski carpet, where L is the system size. The dynamic exponent z is obtained from the relation z = α/β. The estimated exponents break the scaling relation α+ z = 2, which is known to be valid on a regular lattice.

람세이-헌트 증후군에 동반된 미주신경 마비

이상법,이동국 대한임상신경생리학회 2014 Annals of Clinical Neurophysiology Vol.16 No.1

경추 뒤세로인대골화증 환자에서 컴퓨터단층촬영 및 자기공명영상

이상법,배창범,이동국 대한신경과학회 2015 대한신경과학회지 Vol.33 No.1

치매 환자 요양보호사의 부양부담에 미치는 요인

이상법,권오대 대한신경과학회 2015 대한신경과학회지 Vol.33 No.3

Background: The importance of care workers in providing care to patients with dementia is increasing. The burden that care workers experience impacts the health of the patients as well as that of the workers themselves. This study examined the burden experienced by care workers looking after patients with dementia, with the aim of determining the factors associated with the severity of the caregiver burden. Methods: Care workers providing care to patients with dementia were recruited from nine medical care centers in the metropolitan city of Daegu and Gyeongsanbuk-do province. Two hundred and twenty participants were included. During face-to-face interviews with a psychologist, they completed the Burden Interview, Life Satisfaction Index, Beck Depression Inventory, and Beck Anxiety Inventory, and their health status and the severity of dementia in their patients were evaluated. The burden experienced by care workers and the factors affecting it were assessed using statistical analyses. Results: The care workers had a mean score in the Burden Interview of 28. A multiple linear regression analysis revealed that scores for the Life Satisfaction Index and the Beck Anxiety Inventory, as well as the health status and education level of caregivers were associated with the severity of caregiver burden (p<0.05). Conclusions: This study found that the burden of the included Korean care workers ranged from mild to moderate. In addition, their health status, education level, and scores for the Life Satisfaction Index and the Beck Anxiety Inventory were closely related to the burden they experienced in caring for patients with dementia.