• Structural Engineering and Mechanics
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• v.4 no.5
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• pp.469-484
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• 1996

Green's functions are obtained in exact closed-forms for the elastic fields in bi-material elastic solids with slipping interface and differing transversely isotropic properties induced by concentrated point and ring force vectors. For the concentrated point force vector, the Green functions are expressed in terms of elementary harmonic functions. For the concentrated ring force vector, the Green functions are expressed in terms of the complete elliptic integral. Numerical results are presented to illustrate the effect of anisotropic bi-material properties on the transmission of normal contact stress and the discontinuity of lateral displacements at the slipping interface. The closed-form Green's functions are systematically presented in matrix forms which can be easily implemented in numerical schemes such as boundary element methods to solve elastic problems in computational mechanics.

• The Journal of Korean Philosophical History
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• no.29
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• pp.33-54
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• 2010

Woodam(愚潭) Jeong Si-han(丁時翰, 1625-1707) played an important role in the formation and development of the Toegye School. This writing explores the way Woodam understood the thought of Toegye(退溪, 1501-1570) as presented in The Book of Four-Seve Demonstration(四七辨證) The 17th century that Woodam lived in was the period in which monism and dualism coexisted. Woodam's understanding of Toegye's thought can be summarized as follows: 1) Woodam followed Toegye's li(理)-qi(氣) defense and his view on the origin of nature and emotion, acknowledging Toegye as the orthodox transmitter of Zhu Xi's teachings, 2) Woodam considered that the difference between the past and the contemporary teachings was simply caused by the difficulty of comprehending the character "li (principle) ". Thus he criticized Yulgok(栗谷, 1536-1584)'s claim that "that which rises is qi (material force), and that which gives rise to qi is li," and followed instead Toegye's views of the entivity, dynamism, and ultimacy of li and its substantial function. Yet, Woodam further developed Toegye's thought and asserted that "in the midst of the marvelous unity of li and qi, li is always dominant and qi is always ancillary." 3) Woodam criticized Yulgok's thought and advocated Toegye's doctrine of the mutual motion of li and qi(理氣互發說), thereby following Toegye's insistence that difference can be observed in sameness and sameness can be observed in difference, that integrative thinking is needed to constructively embrace both analytic and synthetic judgments. In conclusion, Woodam understood profoundly and correctly Toegye's views on the relationship between li and qi and between nature and emotion, and explained them more concretely. In so doing, he endeavored to live the life by the teachings of Toegye.

• Geomechanics and Engineering
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• v.12 no.3
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• pp.541-560
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• 2017

In this research, experimental and numerical simulations were adopted to investigate the effects of ligament angle on compressive strength and failure mode of rock-like material specimens containing two non-coplanar filled fissures under uniaxial compression. The experimental results show that with the increase of ligament angle, the compressive strength decreases to a nadir at the ligament angle of $60^{\circ}$, before increasing to the maximum at the ligament angle of $120^{\circ}$, while the elastic modulus is not obviously related to the ligament angle. The shear coalescence type easily occurred when ${\alpha}$ < ${\beta}$, although having the same degree difference between the angle of ligament and fissure. Numerical simulations using $PFC^{2D}$ were performed for flawed specimens under uniaxial compression, and the results are in good consistency with the experimental results. By analyzing the crack evolution process and parallel bond force field of rock-like material specimen containing two non-coplanar filled fissures, we can conclude that the coalescence and propagation of crack are mainly derived from parallel bond force, and the crack initiation and propagation also affect the distribution of parallel bond force. Finally, the displacement vectors in ligament region were used to identify the type of coalescence, and the results coincided with that obtained by analyzing parallel bond force field. These experimental and numerical results are expected to improve the understanding of the mechanism of flawed rock engineering structures.

• (The)Study of the Eastern Classic
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• no.41
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• pp.7-35
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• 2010

Jang Hyungang(張顯光, 1554~1570) was one of the very famous Neo-Confucianists of T'oegye School in the Chosun dynasty. Jang, nevertheless, refused to accept Toegye's theory and had developed his own theory called li-qi-gyeong-wi-seol(理氣經緯說). So the theory was very unique in the history of Korean Neo-Confucianism. He matained that Tao(道), meaning the universal process which all beings including the human must follow, is accomplished by the unity of li(理, principle) and qi(ch'i, 氣, material force). He compared li and qi to warp(經) and woof(緯). According to his explanation, Tao is fulfilled by combining li and qi, as a textile is woven the combination of warps and woofs. He could, for I know, succeed to emphasize the unity of li and qii through this theory. Lots of Scholars in the Chosun dynasty criticized Jang's theory of li and qi for regarding li and qi as one, and thought that the theory originated from Luo Ch'inshun(羅欽順, 1465~1547), a famous Neo-Confucianist of in Early Ming China. Luo Ch'inshun maintained li-qi metaphysical monism that li and qi is united entity. In this respect, it seems that Jang's theory is similar to Luo's. However, I think that there are very important differences between the two. It is true that the main characteristics of Jang's theory is the unified relations between li and qi in this world. In the system of his philosophy, nevertheless, the topological position of li and qi are different in grade each other. Jang insisted that li is a supreme being to be materialized and realized through the movement of qi'in the process of universal development. Qi is accordingly only a kind of matter which completes li. In this sense, Jang's theory can be regarded as li metaphysical monism that li is the only substance. It means that Jang Hyeongwang's theory is a great contrast to Luo Ch'inshun's li-qi metaphysical monism.

• Steel and Composite Structures
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• v.35 no.2
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• pp.295-306
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• 2020

This paper deals with free vibration analysis of non-uniform column resting on elastic foundations and subjected to follower force at its free end. The internal pores and graphene platelets (GPLs) are distributed in the matrix according to different patterns. The model is proposed with material parameters varying in the thickness of column to achieve graded distributions in both porosity and nanofillers. The elastic modulus of the nanocomposite is obtained by using Halpin-Tsai micromechanics model. The differential quadrature method as an efficient and accurate numerical approach is used to discretize the governing equations and to implement the boundary conditions. It is observed that the maximum vibration frequency obtained in the case of symmetric porosity and GPL distribution, while the minimum vibration frequency is obtained using uniform porosity distribution. Results show that for better understanding of mechanical behavior of nanocomposite column, it is crucial to consider porosities inside the material structure.

• Advances in concrete construction
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• v.9 no.4
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• pp.413-421
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• 2020

For steel-concrete girders made composite using shear studs, initial damage on studs induced by weld defect, unexpected overloading, fatigue and others might degrade the service performance and even threaten the structural safety. This paper conducted a numerical study to investigate the static behavior of damaged stud shear connectors that were embedded in ultra high performance concrete (UHPC). Parameters included damage degree and damage location. The material nonlinear behavior was characterized by multi-linear stress-strain relationship and damage plasticity model. The results indicated that the shear strength was not sensitive to the damage degree when the damage occurred at 2/3d (d is the stud diameter) from the stud root. An increased stud area would be engaged in resisting shear force as the distance of damage location from stud root increased and the failure section becomes inclined, resulting in a less reduction in the shear strength and shear stiffness. The reduction factor was proposed to consider the degradation of the shear strength of the damaged stud. The reduction factor can be calculated using two approaches: a linear relationship and a square relationship with the damage degree corresponding to the shear strength dominated by the section area and the nominal diameter of the damaged stud. It was found that the proposed method is preferred to predict the shear strength of a stud with initial damage.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.24.1-24.1
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• 2009

The zinc oxide (ZnO) material as the II-VI compound semiconductor is useful in various fields of device applications such as light-emitting diodes (LEDs), solar cells and gas sensors due to its wide direct band gap of 3.37eV and high exciton binding energy of 60meV at room temperature. In this study, the ZnO nanorods were deposited onto homogenous buffer layer/Si(100) substrates by a hydrothermal synthesis. The Effects of the buffer layer annealing and post annealing temperature on the structural and optical properties of ZnO nanorods grown by a hydrothermal synthesis were investigated. For the buffer layer annealing case, the annealed buffer layer surface became rougher with increasing of annealing temperature up to $750^{\circ}C$, while it was smoothed with more increasing of annealing temperature due to the evaporation of buffer layer. It was found that the roughest surface of buffer layer improved the structural and optical properties of ZnO nanorods. For the post annealing case, the hydrothermally grown ZnO nanorods were annealed with various temperatures ranging from 450 to $900^{\circ}C$. Similarly in the buffer layer annealing case, the post annealing enhanced the properties of ZnO nanorods with increasing of annealing temperature up to $750^{\circ}C$. However, it was degraded with further increasing of annealing temperature due to the violent movement of atoms and evaporation. Finally, the buffer layer annealing and post annealing treatment could efficiently improve the properties of hydrothermally grown ZnO nanorods. The morphology and structural properties of ZnO nanorods grown by the hydrothermal synthesis were measured by atomic force microscopy (AFM), field emission scanning electron microscopy (SEM), and x-ray diffraction (XRD). The optical properties were also analyzed by photoluminescence (PL) measurement.

• (The)Study of the Eastern Classic
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• no.37
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• pp.411-439
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• 2009

Fu-Shan(傅山, 1607~1684) was a progressive actualist between the late Ming(明) dynasty and the early Qing(淸) dynasty. He regards the intellectuals at that time as scarecrows leaned on the empty and exaggerative moral philosophy which the neo-confucian of Song(宋) dynasty established. He thinks that the neo-confucian discussion cause harmful side effects, disregarding the utility side and the variety of the actual world. His thought becomes known all in political thought and literature. He asserts that the neo-confucian ideas provides the logical frame which regulates the actual world and creates a kind of absolute moral ideology. Therefore he insists that the Saint in the true sense of the word consequently is the social reformer and revolutionist who exposes the irrational elements of society. He insists that literature also must be able to express vividness of the actual world. He thinks that genuine literature must have creative contents and find one's own free wild way. He asserts that old literary style from the mimicry is the act which goes against human natural. He thinks that the writing must be able to express the actual world.