• 천문학회보
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• 제42권2호
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• pp.37.1-37.1
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• 2017

Since the seminal work of Perrin, physicists have understood in the context of kinetic theory how ink slowly diffuses in a glass of water. The fluctuations of the stochastic forces acting on water molecules drive the diffusion of the ink in the fluid. This is the archetype of a process described by the so-called fluctuation-dissipation theorem, which universally relates the rate of diffusion to the power spectrum of the fluctuating forces. For stars in galaxies, a similar process occurs but with two significant differences, due to the long-range nature of the gravitational interaction: (i) for the diffusion to be effective, stars need to resonate, i.e. present commensurable frequencies, otherwise they only follow the orbit imposed by their mean field; (ii) the amplitudes of the induced fluctuating forces are significantly boosted by collective effects, i.e. by the fact that, because of self-gravity, each star generates a wake in its neighbours. In the expanding universe, an overdense perturbation passing a critical threshold will collapse onto itself and, through violent relaxation and mergers, rapidly converge towards a stationary, phase-mixed and highly symmetric state, with a partially frozen orbital structure. The object is then locked in a quasi-stationary state imposed by its mean gravitational field. Of particular interests are strongly responsive colder systems which, given time and kicks, find the opportunity to significantly reshuffle their orbital structure towards more likely configurations. This presentation aims to explain this long-term reshuffling called gravity-driven secular evolution on cosmic timescales, described by extended kinetic theory. I will illustrate this with radial migration, disc thickening and the stellar cluster in the galactic centre.

• 한국의류학회지
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• 제34권12호
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• pp.1992-2005
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• 2010

Emotion directly affects consumer buying behavior. This study examines Chinese consumers' emotion elicitation process toward a U.S. apparel brand in the Chinese market. Employing a cognitive appraisal theory, this study proposed and tested a conceptual model incorporating three factors of consumer global orientation as antecedents of consumer emotion and purchase intention as a consequence of emotion. Among the ten proposed hypotheses, eight were supported. Of the three antecedents of consumer emotion, exposure to global mass media and cultural openness positively increased Chinese consumers' appraisals of a U.S. apparel brand. Unlike these two antecedents, the effects of exposure to mass migration on consumer appraisals were found to be non significant. The relationships between appraisal dimensions and positive emotion were all supported. Finally, this study confirmed that positive emotions increased Chinese consumers' purchase intentions of a U.S. apparel brand. Theoretical and managerial implications were discussed based on the findings.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3579-3582
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• 2010

We studied the reaction of tri-methylaluminum (TMA) on hydroxyl (OH)-terminated Si (001) surfaces for the initial growth of aluminum oxide thin-films using density functional theory. TMA was adsorbed on the oxygen atom of OH due to the oxygen atom’s lone pair electrons. The adsorbed TMA reacted with the hydrogen atom of OH to produce a di-methylaluminum group (DMA) and methane with an energy barrier of 0.50 eV. Low energy barriers in the range of 0 - 0.11 eV were required for DMA migration to the inter-dimer, intra-dimer, and inter-row sites on the surface. A unimethylaluminum group (UMA) was generated at each site with low energy barriers in the range of 0.21 - 0.25 eV. Among the three sites, the inter-dimer site was the most probable for UMA formation.

• 한국인구학
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• 제11권1호
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• pp.131-145
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• 1988

1960년 이래 한국사회는 빠른 속도로 인구변천을 경험했다. 인구변천으로 인한 인구구조의 변화는 한국사회의 전반적인 현상이기는 하지만, 특히 이 기간중 많은 인구를 도시로 내보내지 않으면 안되었던 농촌지역에서 그 변화의 폭이 더욱 클 수밖에 없다. 이와 같은 관점에서 이 연구는 주로 최근 농촌사회에서 관찰되는 인구구조의 왜곡현상이 주로 농촌-도시로의 인구이동에 원인이 있으며, 지역단위별로 차별적인 영향을 받을 것이라는 점에 착안하여 농촌의 지역단위별 인구특성에 따른 인구분포의 변화를 비교분석하는 데 초점을 두었다. 이 연구결과 밝혀진 결과를 종합해 보면 농촌은 각 지역단위(군)별로 인구구조상의 격차가 매우 크다는 것이 확인되었다. 따라서 각 지역단위별 인구구조의 변화로 예상되는 농촌의 문제는 군부나 면부의 총괄분석을 통해 알려진 농촌 문제보다 각 지역단위별로 분석할 때 알 수 있는 농촌문제가 훨씬 더 심각함을 알 수 있었다. 이 결과는 농촌을 위한 정책수립 과정에서 지역단위별로 특수성이 고려될 수 있어야 한다는 점을 말해준다.

• BMB Reports
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• 제57권6호
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• pp.273-280
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• 2024

Cancer cells metastasize to distant organs by altering their characteristics within the tumor microenvironment (TME) to effectively overcome challenges during the multistep tumorigenesis. Plasticity endows cancer cell with the capacity to shift between different morphological states to invade, disseminate, and seed metastasis. The epithelial-to-mesenchymal transition (EMT) is a theory derived from tissue biopsy, which explains the acquisition of EMT transcription factors (TFs) that convey mesenchymal features during cancer migration and invasion. On the other hand, adherent-to-suspension transition (AST) is an emerging theory derived from liquid biopsy, which describes the acquisition of hematopoietic features by AST-TFs that reprograms anchorage dependency during the dissemination of circulating tumor cells (CTCs). The induction and plasticity of EMT and AST dynamically reprogram cell-cell interaction and cell-matrix interaction during cancer dissemination and colonization. Here, we review the mechanisms governing cellular plasticity of AST and EMT during the metastatic cascade and discuss therapeutic challenges posed by these two morphological adaptations to provide insights for establishing new therapeutic interventions.

• 한국결정성장학회지
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• 제9권6호
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• pp.558-562
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• 1999

승화 성장법을 적용하여 성장된 6H-SiC 결정에 대하여, KSV 이론과 성장 계면에서의 미사면(vicinal plane)상의 step 성장 양상을 근거로 하여, 성장 계면에서의 물질 흡착의 거동과 결함의 생성간의 상호 관계를 고찰하고, micropipes와 내부 결함의 생성 원인을 논하였다. micropipe와 면결함등의 결함들은 ledge 혹은 kink에 침입된 불순물에 의하여 step 성장의 진행이 방해받는 부분에 형성되었다. 따라서, SiC 결정에서 이들 결함의 생성은 SiC 결정 성장 계면에 형성되는 결정학적 step 성장면과 분자 또는 원자들의 격자 이동에 관련이 있음을 알 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.73-76
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• 2007

Electro-Active paper (EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, which result good correlation with each other.

• 한국소음진동공학회논문집
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• 제17권12호
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• pp.1179-1183
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• 2007

Electro-Active paper(EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, and which result in good correlation with each other.

• Bulletin of the Korean Chemical Society
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• 제19권12호
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• pp.1347-1350
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• 1998

The equivalent conductances for tetraethylammonium perchlorate (TEAP), tetrabutylammonium perchlorate (TBAP), tetrahexylammonium perchlorate (THAP), and tetradodecylammonium perchlorate (TDDAP) were measured in pyridine (Py) at 25 ℃. The measured data have been analyzed by Onsager conductance theory. From Kohirausch's law of independent migration of ion, the limiting ionic conductances of tetraalkylammonium ions were determined using the limiting ionic conductance of perchlorate cited from reference. Using those and viscosity of pyridine, the Stokes and hydrodynamic radii of tetraethylammonium, tetrabutylammonium, tetrahexylammonium, and tetradodechylammonium ions were calculated. And, the salvation numbers of corresponding ions were also calculated using the hydrodynamic and crystallographic radii and the volume of one pyridine molecule. From those results, the model of salvation for those ions was extracted by comparison with the model for ion salvation. And the electrostatic Gibbs free energy (ΔGel) fitted for our salvation model was calculated. Those of corresponding ions in pyridine at 25 ℃ also increased with increasing radii of tetraalkylammonium ions. This trend of ΔGel was explained by the different ion-solvent interaction between tetraalkylammonium ion and pyridine.

• 수완나부미
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• 제13권2호
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• pp.37-67
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• 2021

Mazu is considered the famous Chinese Sea Goddess, venerated by seafarers. Mazu belief was conducted in Meizhou County, Fujian Province. Soon worship of Mazu spread quickly to other parts of over the world, especially in Southeast Asia. In China, the Mazu belief was strongly influenced by marine culture, but its marine factors faded when Chinese immigrants had lived together with the Kinh people in Pho Hien (in the north of Vietnam) for more than four centuries. Applying the Acculturation theory, this paper aims to analyze the migration background of the Chinese and their integration into Kinh culture in Pho Hien. It can be said that historical, economic and social context, as well as native government policies have highly affected the manner and the rate of this belief's acculturation. Furthermore, the article explains the reasons for the fading of marine cultural traits and their replacement by the Kinh people's cultural factors in this belief.