• Structural Engineering and Mechanics
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• v.86 no.4
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• pp.443-459
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• 2023

This study investigates the theoretical thermal buckling analyses of thick porous rectangular functionally graded (FG) plates with different geometrical boundary conditions resting on a Winkler-Pasternak elastic foundation using a new higher-order shear deformation theory (HSDT). This new theory has only four unknowns and involves indeterminate integral variables in which no shear correction factor is required. The variation of material properties across the plate's thickness is considered continuous and varied following a simple power law as a function of volume fractions of the constituents. The effect of porosity with two different types of distribution is also included. The current formulation considers the Von Karman nonlinearity, and the stability equations are developed using the virtual works principle. The thermal gradients are involved and assumed to change across the FG plate's thickness according to nonlinear, linear, and uniform distributions. The accuracy of the newly proposed theory has been validated by comparing the present results with the results obtained from the previously published theories. The effects of porosity, boundary conditions, foundation parameters, power index, plate aspect ratio, and side-to-thickness ratio on the critical buckling temperature are studied and discussed in detail.

• Advances in nano research
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• v.16 no.3
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• pp.289-301
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• 2024

In this work, an analytical model employing a new higher-order shear deformation beam theory is utilized to investigate the bending behavior of axially randomly oriented functionally graded carbon nanotubes reinforced composite nanobeams. A modified continuum nonlocal strain gradient theory is employed to incorporate both microstructural effects and geometric nano-scale length scales. The extended rule of mixture, along with molecular dynamics simulations, is used to assess the equivalent mechanical properties of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) beams. Carbon nanotube reinforcements are randomly distributed axially along the length of the beam. The equilibrium equations, accompanied by nonclassical boundary conditions, are formulated, and Navier's procedure is used to solve the resulting differential equation, yielding the response of the nanobeam under various mechanical loadings, including uniform, linear, and sinusoidal loads. Numerical analysis is conducted to examine the influence of inhomogeneity parameters, geometric parameters, types of loading, as well as nonlocal and length scale parameters on the deflections and stresses of axially functionally graded carbon nanotubes reinforced composite (AFG CNTRC) nanobeams. The results indicate that, in contrast to the nonlocal parameter, the beam stiffness is increased by both the CNTs volume fraction and the length-scale parameter. The presented model is applicable for designing and analyzing microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) constructed from carbon nanotubes reinforced composite nanobeams.

• KIEAE Journal
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• v.2 no.4
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• pp.41-47
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• 2002

East Asian explain the changes of substance happened on earth and those of human life with the conceptual frame of "Gi-ki"(地氣; earth vital energy) and organize them by the system of "Feng-shui(風水) theory. The core of Feng-shui theory is reading the expression of the nature and feeling the Gi-ki from the expression. One of the properties of the earth is that the earth has a magnetic field associated with it- the Geomagnetic field. The geomagnetic field is produced by a combination of the effects of electric currents in the earth's liquid core, the magnetization of crustal rocks, external electric current systems that surround the earth and currents induced in the outer layers of the earth by magnetic field variations. The sameness of logic between Feng-shui and geopathic zones is that both are concerned with the discrimination of site and the energy of places, in other words both disciplines are concerned with how the environment can influence people. In this context the operation of Gj-ki can be related with the effect caused by geomagnetic field on site. In this study Jongmyo(宗廟), one of the representative traditional architecture in Korea is selected because the site selection and building layout follows Feng-shui faithfully according to Taejo silok (太祖實錄, Annals of King Taejo). Observing the landforms surrounding Jongmyo, Jongmyo is apparently located in auspicious places named Gumge Poranhyoeng(金鷄抱卵形, a Feng-shui landscape of golden hen sitting on eggs). The geomagnetic investigation of Jongmyo shows that the geomagnetic values of Toekan(the space near Hyeol) are relatively high and uniform and those of Sangweoldae and Haweoldae are decreased in accordance with the distance. The result shows that there is possibility that Feng-shui has scientific basis related with geomagnetic field. Feng-shui theory can suggest a direction for designing the sustainable building for living with nature.

• Advances in materials Research
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• v.12 no.3
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• pp.243-261
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• 2023

This study aims to analyze the mechanical buckling behavior of a single-walled carbon nanotube (SWCNT) integrated with a one-parameter elastic medium and modeled as a Kerr-type foundation under a longitudinal magnetic field. The structure is considered homogeneous and therefore modeled utilizing the nonlocal first shear deformation theory (NL-FSDT). This model targets thin and thick structures and considers the effect of the transverse shear deformation and small-scale effect. The Kerr model describes the elastic matrix, which takes into account the transverse shear strain and normal pressure. Using the nonlocal elastic theory and taking into account the Lorentz magnetic force acquired from Maxwell relations, the stability equation for buckling analysis of a simply supported SWCNT under a longitudinal magnetic field is obtained. Moreover, the mechanical buckling load behavior with respect to the impacts of the magnetic field and the elastic medium parameters considering the nonlocal parameter, the rotary inertia, and transverse shear deformation was examined and discussed. This study showed useful results that can be used for the design of nano-transistors that use the buckling properties of single-wall carbon nanotubes(CNTs) due to the creation of the magnetic field effect.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.3
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• pp.53-60
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• 2000

Although built-environment has not only function but also socio-cultural meanings, the latter is neglected in the modernism. People don't have the identity of their place because they can't communicate with environment. Therefore, expressing the socio-curtural meanings in landscape is one of main issues after the modern era. The meanings of phenomena can be analyzed by the Semiology based on Structurism, the methodology which has been developed in Linguistics and Anthropology since 1900's. The purpose of this study is to adapt Helmslev's model that can effectively explain the meanings of built-environment and interpret the Koreaness, one of important meanings in contemporary urban park, Paris park. The following methods are used for achieving the purpose. 1. Adaptation of the Helmslev's model for interpreting the urban park. 2. Interpretation of the Paris park. 3. Making the types of interpretion of Paris park. The results are as followings: 1. Helmslev's model can explain the content and expression of the urban park in denotation and connotation. 2. Th socio-cultural meanings of Paris park are the relationship of France, Yan and Yin theory, philosophy of Samjae, king's authority. And they are expressed in the pattern of paving, the shape of mounds, fountain, and pond, a picture of the wall, colours of lightings and columns, and a mark of bollards.

• Computers and Concrete
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• v.26 no.3
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• pp.213-226
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• 2020

The present study covenants with the static and free vibration behavior of nanocomposite sandwich plates reinforced by carbon nanotubes resting on Pasternak elastic foundation. Uniformly distributed (UD-CNT) and functionally graded (FG-CNT) distributions of aligned carbon nanotube are considered for two types of sandwich plates such as, the face sheet reinforced and homogeneous core and the homogeneous face sheet and reinforced core. Based on the first shear deformation theory (FSDT), the Hamilton's principle is employed to derive the mathematical models. The obtained solutions are numerically validated by comparison with some available cases in the literature. The elastic foundation model is assumed as one parameter Winkler - Pasternak foundation. A parametric study is conducted to study the effects of aspect ratios, foundation parameters, carbon nanotube volume fraction, types of reinforcement, core-to-face sheet thickness ratio and types of loads acting on the bending and free vibration analyses. It is explicitly shown that the (FG-CNT) face sheet reinforced sandwich plate has a high resistance against deflections compared to other types of reinforcement. It is also revealed that the reduction in the dimensionless natural frequency is most pronounced in core reinforced sandwich plate.

• Computers and Concrete
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• v.25 no.4
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• pp.311-325
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• 2020

In this research work, the hygrothermal and mechanical buckling responses of simply supported FG sandwich plate seated on Winkler-Pasternak elastic foundation are investigated using a novel shear deformation theory. The current model take into consideration the shear deformation effects and ensures the zero shear stresses on the free surfaces of the FG-sandwich plate without requiring the correction factors "Ks". The material properties of the faces sheets of the FG-sandwich plate are assumed varies as power law function "P-FGM" and the core is isotropic (purely ceramic). From the virtual work principle, the stability equations are deduced and resolved via Navier model. The hygrothermal effects are considered varies as a nonlinear, linear and uniform distribution across the thickness of the FG-sandwich plate. To check and confirm the accuracy of the current model, a several comparison has been made with other models found in the literature. The effects the temperature, moisture concentration, parameters of elastic foundation, side-to-thickness ratio, aspect ratio and the inhomogeneity parameter on the critical buckling of FG sandwich plates are also investigated.

• Structural Engineering and Mechanics
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• v.71 no.6
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• pp.627-641
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• 2019

The paper focuses on bending analysis of the functionally graded (FG) plates with arbitrary shapes and boundary conditions. The material property of FG plates is modelled by using the power law distribution. Based on the first order shear deformation plate theory (FSDT), the governing equations as well as boundary conditions are formulated and obtained by using the principle of virtual work. The coupled Boundary Element-Radial Basis Function (BE-RBF) method is established to solve the complex FG plates. The proposed methodology is developed by applying the concept of the analog equation method (AEM). According to the AEM, the original governing differential equations are replaced by three Poisson equations with fictitious sources under the same boundary conditions. Then, the fictitious sources are established by the application of a technique based on the boundary element method and approximated by using the radial basis functions. The solution of the actual problem is attained from the known integral representations of the potential problem. Therefore, the kernels of the boundary integral equations are conveniently evaluated and readily determined, so that the complex FG plates can be easily computed. The reliability of the proposed method is evaluated by comparing the present results with those from analytical solutions. The effects of the power index, the length to thickness ratio and the modulus ratio on the bending responses are investigated. Finally, many interesting features and results obtained from the analysis of the FG plates with arbitrary shapes and boundary conditions are demonstrated.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.126-137
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• 2022

Whether an excellent animation film has vitality and charm largely depends on the aesthetic and emotional experience it brings to the audience, as well as the flexible use of the medium-long shot during the production of the animated film, especially the long take shot. It can then realize the real emotional communication between the animated film and the audience, stimulate the aesthetic experience, and achieve emotional resonance and sublimation. This thesis studies the characteristics and morphological divisions of moving long-shot composition and static composition and explores the diversified theories of animated emotional experience. Additionally, combined with the actual application analysis in the excellent animation feature "Prince Nezha's Triumph Against Dragon King", this thesis discussed the changes in the emotional experience created by the long take shots in the animation. This thesis finally summarized the relationship between the long shots in animation and the emotional experience of the animation creators, and how long shots stimulate viewers' aesthetic and emotional experience. In this way, it also provides a reference for future animation theory research, and finally creates animation works that bring high-quality emotional experience to the audience.

• Journal of Korean Medical classics
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• v.12 no.2
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• pp.16-53
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• 1999

On the viewpoint of Nae-Kyung and Ju-Yeok, the Seok-Kok's Pu-Yang-Non and other oriental medical doctor's Po-Eum-Eok-Yang, Pu-Yang-Eok-Eum theory which are on the basis of the Kun-Shin-Sang-Wha theory of Nae-Kyung and Myung-Mun theory of Nan-Kyung were compared and studied. The results were as follows : 1. Ju-Yeok and Nae-Kyung said the South is Fire. And explained it as the chief object of life activity by likening to king or saint. And said the North is Water. but didn't mentioned that there exists Fire. The activity of Kun-Wha is regarded as the the chief object of life activity and the Shin-Su can be vatalized by receiving the Shim-Kun-Wha. Therefore, the Seok-Kok's opinion that Shang-Wha is the Fire received by Shin-Su matchs the theory of Nae-Kyung and Nan-Kyung. 2. The Kidney(Shin) in Nae-Kyung means Puk-Bang- Han-Su(The North Cold Water) which has two characters, charging and discharging, ascending and descending. The paragrap "Kam-Ga-Seub(坎加習)" in Ju-Yeok means Puk-Bang-Su(The North Water) which also has two characters, charging and discharging, ascending and descending. The beginning and the end. And One Eum and Two Yang of Ri Sign of divination(離卦) cannot be divided into Su-Jang and Wha-Jang, the same as that, One Yang and Two Eum of Kam Sign of divination(坎卦) is Puk-Bang-Han-Su which cannot be divided into Shin and Myung-Mun. The theory of Choa-Shin-Woo-Myung-Mun of Nan-Kyung is the result that the Shin which has two characters is regarded as two organs. Therefore, from the viewpoint of Nae-Kyung and Ju-Yeok, the Seok-Kok's opinion that the Shin is the Puk-Bang-Han-Su which charges from the right and discharges to the left is more proper. 3. For the first time, the right kidney(Woo-Shin) defined as Myung-Mun in the Nan-Kyung and it is trailblazing theory which dosen't exist in the Nae-Kyung. But from the viewpoint of Nae-Kyung, Myung-Mun-Shang-Wha which some oriental medical doctors thought importantly is considered as Shim-Po which is in charge of the order of Shim(心命). 4. The rush of heat to the upper part(上熱) is raised by blind acting of Shang-Wha which exists in the lower part. This theory is on the basis of the Myung-Mun-Shang-Wha theory of Nan-Kyung. The theory that Wha is in the Shin(Kidney) doesn't exist and only the theory exists that the fever happens by the Kun-Wha not going down but ascending in the Nae-Kyung. Therefore the Shang-Wha blind acting theory of the lower part is not coincided with the theory of Nae-Kyung. 5. When the Vital power(陽氣) is blocked by bad tendencies(邪氣) like uncontrolled joy and anger or too much cold and heat etc, the trapped heat(鬱熱) or Ascending Shang-Wha apper, so Vital power itself cannot have blind activity or excess. Therefore, the theory of oriental medical doctors that the remaining vital power is the fire(氣有餘便是火) cannot be materialized. 6. On the basis of the Woo-Shin-Myung-Mun theroy, oriental medical doctors attached importance to Shin-Eum and Shin-Yang. So they emphasized on Ja-Eum-Gang-Wha or On-Bo-Shin-Yang for curing the Fire. Contrarily, On the viewpoint of siding with the vital power which is the Good and repressing the bad tendency which is the Bad, and another viewpoint that when the vital power which is Shim-Kun-Wha moves through the body consistently and fills up the body, then the enery and blood can be made, the Seok-Kok's theory is coincided with the theory of Nae-Kyung.