• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.726-733
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• 1989

Conduction heat transfer in heat spreaders with concentrated heat sources is analyzed by finite element method calculation and the results are compared to analytical solutions for simplified cases. The local temperature rise is dependent on the heat flux, thermal conductivity of the spreader material, and the contact size of the heat source. The effect of the adjacency of other heat sources is also examined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.53-54
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• 2007

Charged particle type display using particles which have opposite charge and color is based on effect of reversible optical property due to electric field. we designed mask pattern for fabrication of the charged particle type display based on glass substrate and investigated cell gap dependent of driving voltage and selectively driving method. the panel driven by our selectively driving method, we could obtain image which had vary little crosstalk caused by electrical interference and conform the last image maintained by memory effect without additional voltage.

• Structural Engineering and Mechanics
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• v.67 no.2
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• pp.143-153
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• 2018

Thermal buckling of nonlocal flexoelectric nanoplates incorporating surface effects is analyzed for the first time. Coupling of strain gradients and electrical polarizations is introduced by flexoelectricity. It is assumed that flexoelectric nanoplate is subjected to uniform and linear temperature distributions. Long range interaction between atoms of nanoplate is modeled via nonlocal elasticity theory. The residual surface stresses which are usually neglected in modeling of flexoelectric nanoplates are incorporated into nonlocal elasticity to provide better understanding of the physic of problem. A Galerkin-based approach is implemented to solve the governing equations derived from Hamilton's principle are solved. The verification of obtained results is performed by comparing buckling loads of flexoelectric nanoplate with previous data. It is shown that buckling loads of flexoelectric nanoplate are significantly affected by thermal loading type, temperature change, nonlocal parameter, surface effect, plate thickness and boundary conditions.

• Earthquakes and Structures
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• v.26 no.4
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• pp.299-309
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• 2024

The present paper develops application of third-order shear deformation theory (TSDT) and modified couple stress theory (MCST) to size-dependent bending analysis of a functionally graded cylindrical micro-shell. The radial and axial displacement components are described based on TSDT for more accurate analysis. The effect of small scales is accounted based on MCST. The principle of virtual work is used for derivation of bending governing equations. The solution is presented for a simply-supported boundary condition to account the influence of various important parameters such as micro length scale parameter, in-homogeneous index and some dimensionless geometric parameters such as length to radius and length to thickness ratios on the bending results. A comparative analysis is presented to examine the effect of order of employed shear deformation theory on the axial and radial displacements.

• Structural Engineering and Mechanics
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• v.76 no.6
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• pp.765-779
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• 2020

This article presents a nonclassical size dependent model based on the modified couple stress theory to study and analyze the bending behavior of perforated microbeams under different loading patterns. Modified equivalent material and geometrical parameters for perforated beam are presented. The modified couple stress theory with one material length scale parameter is adopted to incorporate the microstructure effect into the governing equations of perforated beam structure. The governing equilibrium equations of the perforated Timoshenko as well as the perforated Euler Bernoulli are developed based on the potential energy minimization principle. The Poisson's effect is included in the governing equilibrium equations. Regular square perforation configuration is considered. Based on Fourier series expansion, closed forms for the bending deflection and the rotational displacements are obtained for simply supported perforated microbeams. The proposed methodology is validated and compared with the available results in the literature and an excellent agreement is detected. Numerical results demonstrated the applicability of the proposed methodology to investigate the bending behavior of regularly squared perforated beams incorporating microstructure effect under different excitation patterns. The obtained results are significantly important for the design and production of perforated microbeam structures.

• Journal of Investigative Cosmetology
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• v.14 no.3
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• pp.386-404
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• 2018

Here, we aimed to determine, using meta-analyses, the relative importance of factors influencing cosmetic purchasing behaviors. Specifically, effect sizes were compared for studies that included and excluded consumers aged in their fifties to identify and rank factors that have a major impact on the purchasing behavior of new seniors-individuals who have recently emerged as an important consumer group in the cosmetics market. To this end, 77 Korean journal articles, and masters and doctoral theses with cosmetic purchasing behavior as a dependent variable published between 2008 and 2017 were selected, and effect sizes of correlation coefficients were calculated for relevant variables. The study findings are as follows. First, the total effect size for factors influencing purchase behavior of cosmetics was slightly larger than medium and was statistically significant. Second, mediators, age, gender, item, price, and source were found to have statistically significant effect sizes. Third, for studies that included consumers aged in their fifties, user attributes and brand attributes were identified as important variables that were more influential at the purchase intention stage than the purchase stage, suggesting an age-group effect on cosmetic purchasing behavior. By identifying factors influencing cosmetic purchasing behaviors using a comparison of studies with and without consumers aged in their fifties, there appears to be significant implications for cosmetic marketing strategies aimed at new seniors.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.213-213
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• 2012

It has been known that quantum confinement effect of CdSe nanocrystal was observed by increasing the number of deposition cycle using successive ionic layer adsorption and reaction (SILAR) method. Here, we report on thermally-induced quantum confinement effect of CdSe at the given cycle number using spin-coating technology. A cation precursor solution containing $0.3\;M\;Cd(NO_3)_2{\cdot}4H_2O$ is spun onto a $TiO_2$ nanoparticulate film, which is followed by spinning an anion precursor solution containing $0.3\;M\;Na_2\;SeSO_3$ to complete one cycle. The cycle is repeated up to 10 cycles, where the spin-coated $TiO_2$ film at each cycle is heated at temperature ranging from $100^{\circ}C$ to $250^{\circ}C$. The CdSe-sensitized $TiO_2$ nanostructured film is contacted with polysulfide redox electrolyte to construct photoelectrochemical solar cell. Photovoltaic performance is significantly dependent on the heat-treatment temperature. Incident photon-to-current conversion efficiency (IPCE) increases with increasing temperature, where the onset of the absorption increases from 600 nm for the $100^{\circ}C$- to 700 nm for the $150^{\circ}C$- and to 800 nm for the $200^{\circ}C$- and the $250^{\circ}C$-heat treatment. This is an indicative of quantum size effect. According to Tauc plot, the band gap energy decreases from 2.09 eV to 1.93 eV and to 1.76 eV as the temperature increases from $100^{\circ}C$ to $150^{\circ}C$ and to $200^{\circ}C$ (also $250^{\circ}C$), respectively. In addition, the size of CdSe increases gradually from 4.4 nm to 12.8 nm as the temperature increases from $100^{\circ}C$ to $250^{\circ}C$. From the differential thermogravimetric analysis, the increased size in CdSe by increasing the temperature at the same deposition condition is found to be attributed to the increase in energy for crystallization with $dH=240cal/^{\circ}C$. Due to the thermally induced quantum confinement effect, the conversion efficiency is substantially improved from 0.48% to 1.8% with increasing the heat-treatment temperature from $100^{\circ}C$ to $200^{\circ}C$.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.397-404
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• 2021

The web-based crowdfunding platform provides small-cap companies the opportunity to reduce financial risks and to reliably produce new products through pre-orders. Meanwhile, crowdfunding projects are also helping companies as a channel to test new products before mass production. Despite these advantages, from the point of view of businesses and consumers, it is true that web-based crowdfunding platforms have limitations in the retail environment. For example, the limited social elements of a web-based platform are somewhat in conflict with the basic characteristics of crowdfunding projects - which inevitably demand high social influences for the success. As such, understanding the mechanisms of social factors of crowdfunding platforms from the consumers' perspective is important. Therefore, in this study, we empirically tested the effect of social factors of crowdfunding platform on consumer participation and evaluation. Based on the Social Influence Theory and Social Presence Theory, we developed a conceptual framework where the social group size and social presence of other backers were the independent variables and the purchaser's intention to participate as the dependent variable. In the results, the size of the social group size and the perceived social presence have a significant positive effect on purchaser's participation intent. In addition, the social presence had a greater influence on the purchaser's intention to participate than the size of the sponsor's social group. We believe that our findings contribute to the extant literature by empirically demonstrating the valid effect of social factors of crowdfunding platforms on consumer evaluations.

• The Journal of Information Systems
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• v.29 no.2
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• pp.265-286
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• 2020

Purpose Among various psychosocial factors, negative social comparison, attention blocking to stimuli, and cognitive interference via information overload are considered most critical in hindering the effective performance improvement of computer-based idea generation. Given that the effect of negative social comparison along with a plausible solution based on the notion of performance feedback and goal setting has been successfully addressed, this study focused on the remaining issues of "attention blocking to stimuli and cognitive interference via information overload" and attempted to find a way to alleviate the effect of such process losses on performance. Design/methodology/approach A 2 × 4 between-subjects design was used, crossing cognitive ability (high and low) and personality (extroversion and introversion). Five subjects per each treatment were randomly selected to make the sample size equal. The group simulator was used to measure individual-level performance. The dependent variables were the quantity of and quality score of ideas. The manner by which these performance measures were operationalized was consistent with prior studies. An additional analysis using the number of diverse ideas was also conducted. Findings Three arguments were made in this study: (1) high cognitive individuals would perform better than low cognitive individuals, (2) extraverted individuals would perform better than introverted individuals, and (3) cognitive ability and personality would interact such that individuals in Q1 would have the highest performance. Cognitive ability had an effect on quality not quantity. Personality had an effect on both quantity and quality. An interaction between cognitive ability and personality was not found due to small sample size despite the use of the group simulator.

• Journal of Korea Game Society
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• v.19 no.2
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• pp.33-44
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• 2019

This study meta-analyzed the effect of 32 research papers on children in academic journals published with domestic degrees and gameplay Therapy programs (2004-2017). As a result, the total effect size was 0.971, a large effect size. The impact scale by variable factor of disabled children, ages 3 to 5 years by age, and the impact scale of psychological variables by dependent variable were reported, with 11 to 15 sessions per process, total number of sessions 16 times or more, session count per week, and session count 61 to 90 minutes. The biggest research is meaningful in that it is the first comprehensive and objective analysis of gameplay Therapy programs and is expected to be used as basic data in treatment design when performing gameplay Therapy programs on clinical sites.