• Korean Journal of Metals and Materials
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• v.47 no.6
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• pp.372-377
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• 2009

We report on hysteresis behavior in the electrical resistance-hydrogen concentration of Pd thin films. The variation of the electrical resistance has been investigated during the process of absorption and desorption of hydrogen gas ($H_{2}$) as a function of thickness of Pd thin films. The hysteresis behavior in the electrical resistance with $H_{2}$ concentration was found for Pd thin films and consists of $\alpha$ phase, ${\alpha}+{\beta}$ phase, and $\beta$ phase regions. The sensitivity of Pd thin films with $H_{2}$ concentration was found to follow Sieverts' law in the $\alpha$ phase region. However, the sensitivity was observed to increase abruptly with $H_{2}$ concentration in the ${\alpha}+{\beta}$ phase co-exist region. This is because Pd-H interaction is stronger in the $\beta$ phase than in the $\alpha$ phase and needs a higher concentration gradient as a driving force to desorb. The formation of the $\beta$ phase also was observed to cause the structural change because of the lattice expansion during absorption. The hysteresis height and the trace of structural change were affected by the thickness of the Pd film. As the film becomes thinner, the hysteresis height becomes lower and the amount of delamination on the surface becomes smaller. For films thinner than 20 nm in thickness, the delamination was not found but electrical resistance hysteresis was still observed.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.148-155
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• 2018

To get a better understanding of the effect of physicochemical properties and microstructure on $SO_2$ absorption behavior of DESs with different molar ratios of EmimCl and EG (from 2:1 to 1:2), densities (${\rho}$), viscosities (${\eta}$), speeds of sound (u), refractive indices ($n_D$), and thermal decomposition temperatures ($T_d$) of EmimCl-EG DESs were measured and used to obtain the other derived properties, such as thermal expansion coefficient (${\alpha}_p$) and activation energy for viscous flow ($E_{\eta}$). Moreover, FT-IR spectra and in situ variable-temperature NMR spectroscopy were employed to study the microstructures of DESs. Based on physicochemical and spectroscopic properties, the influence of the concentrations of EmimCl on the interactions in DESs was explored to be associated with their $SO_2$ absorption behavior. The results show that the interactions between $Emim^+$ and $Cl^-$ of EmimCl is gradually weakening with increasing the concentration of EG in DESs by forming of hydrogen bond interaction of $O-H{\cdots}Cl^-$, resulting in a decrease of ${\rho}$, ${\eta}$, u, $n_D$, and $T_d$ of DESs, and hindering the charge-transfer interaction of $SO_2$ with $Cl^-$ and deceasing $SO_2$ capture capacity. Moreover, the $SO_2$ absorption capacity of DESs is proportional to their ${\rho}$ and $E_{\eta}$, respectively.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.187-197
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• 2022

This study examined the effects of game genre, news media with differing political ideologies, and game-related information sources on gamer issue participation by performing a hierarchical regression model, using an online survey on Korean gamers (N=1,362). As a result of the study, playing specific genres of games played a positive role in gamer issue participation. The group behavior or collective action for or against game regulation reported in the liberal/moderate media acted as a mobilization cue for readers and potentially encouraged gamers to take social action. But the conservative media, which used governmental organizations and interest groups as sources of information, had a negative impact on real-life participatory behavior. The biased journalism practice of the mass media on game-related social issues influenced gamers' social and political behavior through corrective action. This study is significant in empirically analyzing the relationship between political ideology, game genre, media use, and gamers' social participation. The current research suggests the improvement of game regulation policy and the need for theoretical and conceptual expansion of game research.

• Steel and Composite Structures
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• v.47 no.2
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• pp.269-287
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• 2023

The WGJ420 fire-resistant weathering (FRW) steel is developed and manufactured with standard yield strength of 420 MPa at room temperature, which is expected to significantly enhance the performance of steel structures with excellent fire and corrosion resistances, strong seismic capacity, high strength and ductility, good resilience and robustness. In this paper, the mechanical properties of FRW steel plates and buckling behavior of columns are investigated through tests at elevated temperatures. The stress-strain curves, mechanical properties of FRW steel such as modulus of elasticity, proof strength, tensile strength, as well as corresponding reduction factors are obtained and discussed. The recommended constitutive model based on the Ramberg-Osgood relationship, as well as the relevant formulas for mechanical properties are proposed, which provide fundamental mechanical parameters and references. A total of 12 FRW steel welded I-section columns with different slenderness ratios and buckling load ratios are tested under standard fire to understand the global buckling behavior in-depth. The influences of boundary conditions on the buckling failure modes as well as the critical temperatures are also investigated. In addition, the temperature distributions at different sections/locations of the columns are obtained. It is found that the buckling deformation curve can be divided into four stages: initial expansion stage, stable stage, compression stage and failure stage. The fire test results concluded that the residual buckling capacities of FRW steel columns are substantially higher than the conventional steel columns at elevated temperatures. Furthermore, the numerical results show good agreement with the fire test results in terms of the critical temperature and maximum axial elongation. Finally, the critical temperatures between the numerical results and various code/standard curves (GB 51249, Eurocode 3, AS 4100, BS 5950 and AISC) are compared and verified both in the buckling resistance domain and in the temperature domain. It is demonstrated that the FRW steel columns have sufficient safety redundancy for fire resistance when they are designed according to current codes or standards.

• Computers and Concrete
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• v.32 no.1
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• pp.99-117
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• 2023

The crack under the influence of the higher intensities of the stresses grows and the structure gets collapsed with the time when the crack length reaches to critical value. Therefore, the fracture behavior of a structure in terms of stress intensity factors (SIF) becomes important to determine the remaining fracture strength and capacity of material and structure for avoiding catastrophic failure, increasing safety and further improvement in the design. The robustness of the method has been demonstrated by comparing the numerical results with analytical and experimental results of some problems. XFEM is used to model cracks and holes in structures and predict their strength and reliability under service conditions. Further, XFEM is extended with a stochastic method for predicting the sensitivity in terms of output COVs and fracture strength in terms of mean values of stress intensity factors (SIFs) of a structure with discontinuities (cracks and holes) under tensile loading condition with input individual and combined randomness in different system parameters. In stochastic technique, the second order perturbation technique (SOPT) has been used for the predicting the fracture behavior of the structures. The stochastic/perturbation technique is also known as Taylor series expansion method and it provides the reliable results if the input randomness is less than twenty percentage. From the present numerical analysis it is observed that, the crack tip near to the hole is under the influence of the stress concentration and the variational effect of the input random parameters on the crack tip in terms of the SIFs are lesser so the COVs are the less sensitive. The COVs of mixed mode SIFs are the most sensitive for the crack angles (α=45° to 90°) for all the values of c₁ and d₁. The plate with the shorter distance between hole and crack is the most sensitive with all the crack angles but the crack tip which is much nearer to the hole has the highest sensitivity.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.21-43
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• 2015

Korean floricultural industry has grown under the full backing of government, as it placed itself as the main export item since 2000s. Despite its high-speed growth after the domestic production scale of trillion won, the floricultural industry lost its pace after 2005, due to the market-opening of agricultural product and global economic depression. Although the national income is growing and the level of civilized living is following, spending on flowers is faltering. As of such circumstances, necessity for analyzing flower consumption trend and behavior has came out, along with the calls for expansion plan of flower consumption, under the basis of result analysis on consumer reports. The result of the research contains the trend/consumption behavior analysis on domestic and foreign flower industry to boost floricultural industry, along with reviews on various studies of the developmental process of domestic and foreign cut-flowers/pot-plants consumption trend. Also this study has reached to the various recognition of people toward flower, through a public survey. Through such results, this study would like to propose the measures for diffusion of flower-consumption culture, achieving the improvement of life-quality of public along. First, efforts on reviewing the customer accessibility is essential to create flower- culture and the consumption. Second, to eliminate the obstacles that prevents flowers from public's daily life is essential. Third is the effective public-relations on flowers. To create consuming culture and to adhere the positive images, it is essential to research and systematically organize categories of color, scent, and elements of flower and utilize them. Last proposal is the organization of flower-concerned personnels and the leading groups. The change is affected by the economical, social environment, along with the emotions of consumers. Therefore the necessity for the leading group to be the control-tower of such changes are very clear.

• Journal of the Korean housing association
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• v.18 no.3
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• pp.19-29
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• 2007

This study is aimed at interpreting into changes and characters of function applied into quantative analysis in ubiquitous house. Digital technology being introduced into architectural fields, It applied expansively from design and construction to user's convenience. The application of digital technology is presented to various change like effectiveness and exactness in design and function of space, which is overlayed digital space to physical space beyond the extent of receiving human needs in physical space. In ubiquitous house, digital technologies are supplied to function coordinated with life, appreciating into positional informations of human and materials, spatial informations. Ubiquitous house is comparably effective into funtional expansion, user's convenience, safty, which, for the future, is going to using on housing of high performance encouraging the application of advanced technology. Therefore this study is classified into human behaviors, functions, performances and characters of digital system in ubiquitous house, which being established into the relation of elements, is interpreted numerically into functional changes and charats being applied to ARM.

• Coupled systems mechanics
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• v.1 no.2
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• pp.155-163
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• 2012

This paper presents analytical approximate solutions for the initial post-buckling deformation of the pipes in oil and gas wells. The governing differential equation with sinusoidal nonlinearity can be reduced to form a third-order-polynomial nonlinear equation, by coupling of the well-known Maclaurin series expansion and orthogonal Chebyshev polynomials. Analytical approximations to the resulting boundary condition problem are established by combining the Newton's method with the method of harmonic balance. The linearization is performed prior to proceeding with harmonic balancing thus resulting in a set of linear algebraic equations instead of one of non-linear algebraic equations, unlike the classical method of harmonic balance. We are hence able to establish analytical approximate solutions. The approximate formulae for load along axis, and periodic solution are established for derivative of the helix angle at the end of the pipe. Illustrative examples are selected and compared to "reference" solution obtained by the shooting method to substantiate the accuracy and correctness of the approximate analytical approach.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.383-390
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• 2002

The new seismic isolation system (StLRB) is developed, which can separate non-seismic displacements which come from the thermal expansion etc. in LRB design. The StLRB has 3 components, sliding system (PTFE + stainless plate), LRB (lead rubber bearing) and STU (shock transmit units). In this project, the StLRB is designed to apply to the bridge structure by analyzing the characteristics of each component and also the dynamic behavior of the structure was analyzed by non-linear analysis. The verification test was performed to show the two stages separated by STU units. Test results show the effectiveness of both the separation and the seismic isolation performance.

• Proceedings of the Costume Culture Conference
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• 2004.04a
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• pp.107-108
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• 2004

Clothing among lots of products is a means to express individuality and lifestyle of individual, its functions and uses are changing. Recently, it is asking the higher grade, specialization, diversity of production, because of the influence of changed lifestyle of consumers(Chang, 1999). Knitwear that can satisfy such as consumer’s desire, and give the soft and convenient feeling is a popular fashion item that women can enjoy because of its unique characters like the flexibility, expansion, and drape. (omitted)