• Language Facts and Perspectives
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• v.48
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• pp.385-415
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• 2019

This study analyzes mobile media-based writing aspects in terms of behavior induction under the premise that the digital media environment is built around mobile. The actual space where the digital writes are performed is a separate platform. The platform facilitates interaction by providing tools and rules to provide infra and participate in a variety of participants. In a mobile environment, writing is done through social platforms. In digital media, images are no longer content that supplements text. On the contrary, the tendency to use text as subtitles has been strengthened to enhance the message delivery power of video. The following are the aspects of digital writing based on the platform or application of mobile media. Second is the generalization of "textual extension." Third, the expansion of the 'visual style' of text is obvious. The affordance of mobile media is based on perceived affordance. However, mobile media users are not just aware of and understand the information provided by the media's interface. The active use of media based on the transformation of behavioral induction should be understood as the result of the accumulation of numerous experiences of interactions driven by iteration of performance induced by behavioral induction. The future research, therefore, should be conducted in the direction of analyzing new usage patterns of mobile media instead of staying on the behavioral induction based on understanding the perceived behavioral induction of users.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.4
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• pp.300-309
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• 2017

A spacecraft obtains a reaction momentum required for an orbit correction and an attitude control by exhausting a combustion gas through a small thruster in space. If the exhaust plume collides with spacecraft surfaces, it is very important to predict the exhaust plume behavior of the thruster when designing a satellite, because a generated disturbance force/torque, a heat load and a surface contamination can yield a life shortening and a reduction of the spacecraft function. The purpose of the present study is to ensure the core technology required for the spacecraft design by analyzing numerically the exhaust gas behavior of the 10 N class bipropellant thruster for an attitude control of the spacecraft. To do this, calculation results of chemical equilibrium reaction between a MMH for fuel and a NTO for oxidizer, and continuum region of the nozzle inside are implemented as inlet conditions of the DSMC method for the exhaust plume analysis. From these results, it is possible to predict a nonequilibrium expansion such as a species separation and a backflow in the vicinity of the bipropellant thruster nozzle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.451-456
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• 1995

To elucidate the intrinsic rheological properties of carboxymethyl chitin (CM-chitin) from the shell of red snow cyab (Chinonecetes japonicus), the configuration and polyelectrolyte behavior of CM-chitin in low concentration solution were investigated. Unperturbed dimensions were ranged from $127{\AA}\;to\;113{\AA}$ as root mean square end-to-end distance$(r_0)$, $52{\AA}$ to $46{\AA}$ as radius of gyration$(S_0)$. The intramolecular expansion tarter(a) was not varied with molecular weight and was 2.1. And effective bond length $(b_0)$ was $14.5{\AA}$. In perturbed condition, Flory constant was $2.35\times10^{21}$. When ionic strength were 0.02 and 1.0, intrinsic viscosity were 1.95dl/g and 1,06 dl/g, respectively. These results suggested that CM-chitin is a polyelectrolyte in aqueous media. At infinite ionic strength, intrinsic viscosity was 0.91dl/g. The intrinsic stiffness of CM-chitin backbone was estimated by evaluating the stiffness parameter (B) as 0.11 and agreed well with the results of k-carrageenan.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.2
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• pp.17-27
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• 2011

This paper describes an experimental study and finite element analysis (FEA) carried out for investigating thermal deformation behavior of solders, resulting from temperature change in the solder. With such a goal in mind, a shear specimen that was composed of two metal bars having different coefficient of thermal expansion and solder blocks placed between two bars was designed and fabricated. Two different types of solder blocks, eutectic solder (Sn/36Pb/ 2Ag) and lead-free solder (Sn/3.0Ag/0.5Cu) were tested as well. Fringe patterns for several temperature steps were recorded and analyzed for three temperature cycles using a real-time moir$\acute{e}$ setup. The experimental data was verified with FEA and used to evaluate the suitability for numerous solder constitutive models available in literatures. FEA employing Anand material model suggested by Darveaux et al. and Chang et al. were found to be in an excellent agreement with the experimental results for the eutectic solder and the lead-free solder, respectively. In addition, numerical predictions on bending displacement, shear strain and viscoplastic distortion energy are documented and viscoplastic deformation behavior of two types of solder material are compared.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.892-899
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• 2002

Among the methods for enhancement of load-carrying capacity on flexural concrete member, recently, a concept is being investigated which replaces the steel in a conventional reinforced concrete member with a fiber reinforced polymer(FRP) shell. This study focuses on modeling of the structural behavior of concrete surrounded with FRP shells in flexural bending members. A numerical model of fiber cross-sectional analysis is proposed to predict the stress and deformation state of the FRP shell and concrete. The stress-strain relationship of concrete confined by a FRP shell is formulated to be based on the constitutive law of concrete in multi-axial compressive stress state, in assuming that the compression response is dependent on the radial expansion of the concrete. To describe the FRP shell behavior, equivalent orthotropic properties of in-plane behavior from classical lamination theory are used. The present model is validated to compare with the experiments of 4-point bending tests of FRP shell concrete beam, and has well predicted the moment-curvature relationships of the members, axial and hoop strains in the section, and the enhancement of confinement effect in concrete surrounded by FRP shell.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.969-979
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• 2012

In this study, the effects of cosurfactant on phase equilibrium and dynamic behavior were studied in systems containing nonylphenol ethoxylate (NP) surfactant solutions and nonpolar hydrocarbon oils. All the cosurfactants used during this study such as n-pentanol, n-octanol and n-decanol acted as a hydrophobic additive and the hydrophobic effect was found to increase with both increases in chain length and amount of addition of a cosurfactant. Dynamic behavior studies under hydrophilic conditions showed that the solubilization of hydrocarbon oil by NP micellar solution is controlled by an interface-controlled mechanism rather than a diffusion-controlled mechanism. Both spontaneous emulsification of water into oil phase and expansion of oil drop were observed under lipophilic conditions because of diffusion of surfactant and water into oil phase. Under conditions of a three phase region including a middle-phase microemulsion, both rapid solubilization and emulsification of oil into aqueous solutions were found mainly due to the existence of ultralow interfacial tension.

• KDI Journal of Economic Policy
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• v.13 no.2
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• pp.21-39
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• 1991

This paper introduces a two-sector model to analyze the real and monetary determinants of Korea's real exchange rate. So far, most studies on Korea's exchange rate have concentrated on the behavior of nominal exchange rate, but this study proposes a dynamic model of real exchange rate behavior in developing countries and estimates the real and financial determinants of Korea's real exchange rate behavior. The estimation was performed over the period of 1980-89. The results show many interesting things. First, the monetary and fiscal expansion led to a real appreciation, which suggests that the monetary and fiscal stances be kept sound for a real depreciation. Second, the improvement in the terms of trade led to a real depreciation. This experience is in the contrast to the popular view that the improvement in the terms of trade will result in a real appreciation. Third, the productivity growth led to a real appreciation, but this effect of the Ricardo-Balassa type was not significant. Finally, the nominal devaluation was quite effective to produce a real depreciation. This result also supports Korea's exchange rate policy in the 1980s which was based upon the real target approach instead of nominal anchor approach.

• Journal of the Korea Concrete Institute
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• v.19 no.2
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• pp.189-197
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• 2007

Concrete tunnel lining must be designed to having the fireproof performance because the lining are sometimes exposed to very high temperature due to traffic accident. Such fire temperature may cause explosion of concrete, or collapse of tunnel structure. The purpose of this study is to obtain the fundamental fireproof behavior of fire resistance-engineered cementitious composites(FR-ECC) under fire temperature in order to use the fire protection material in tunnel lining system. The present study conducted the experiment to simulate fire temperature by employing 2 types of FR-ECC and investigated experimentally the explosion and cracks in heated surface of these FR-ECC. Employed temperature curve were hydro carbon(HC, ECl) criterion, which are severe in various criterion of fire temperature. The numerical analysis is carried out the nonlinear transient heat flow analysis and verified against the experimental data. The complex features of behavior in fire conditions, such as thermal expansion, plasticity, cracking or crushing, and material properties changing with temperature are considered. By the use of analytical model, the concrete tunnel subjected to fire loads were analyzed and discussed. With comparison of current concrete materials and FR-ECC, the experimental and analytical results of FR-ECC shows the better fire resistance performance than the other.

• Journal of the Korea Concrete Institute
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• v.19 no.3
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• pp.283-292
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• 2007

A research projects is currently being conducted to develop a nonlinear finite element analysis methods for predicting the structural behavior of reinforced concrete frame structures, exposed to fire. As part of this, reinforced concrete frames subjected to fire loads were analyzed using the nonlinear finite-element program DIANA. Two numerical steps are incorporated in this program. The first step carries out the nonlinear transient heat flow analysis associated with fire and the second step predicts the structural behavior of reinforced concrete frames subjected to the thermal histories predicted by first step. The complex features of structural behavior in fire conditions, such as thermal expansion, plasticity, cracking or crushing, and material properties changing with temperature are considered. A concrete material model based on nonlinear fracture mechanics to take cracking into account and plasticity models for concrete in compression and reinforcement steel were used. The material and analytical models developed in this paper are verified against the experimental data on simple reinforced concrete beams. The changes in thermal parameters are discussed from the point of view of changes of structure and chemical composition due to the high temperature exposure. Although, this study considers codes standard fire for reinforced concrete frame, any other time-temperature relationship can be easily incorporated.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.305-313
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• 2012

Unreinforced masonry buildings represent a significant portion of the existing and historical buildings around the world. Recent earthquakes have shown the need for seismic retrofitting for these types of buildings. Various types of retrofitting materials (i.e., shotcrete, ECC and Fiber Reinforced Polymer sheets (FRPs)) for unreinforced masonry buildings (URM) have been developed. Engineers prefer to use FRPs, because these materials enhance the shear strength of the wall without expansion of wall sectional area and adding weight to the total structure. However, the complexity of the mechanical behavior of the masonry wall and the lack of experimental data from walls retrofitted by FRPs may cause problems for engineers to determine an appropriate retrofitting level. This paper investigate in-plane behavior of URM and retrofitted masonry walls using two different types of FRP materials to determine and provide information for the retrofitting effect of FRPs on masonry shear walls. Specimens were designed to idealize the wall of a low-rise apartment which was built in 1970s in Korea with no seismic reinforcements with an aspect ratio of 1. Retrofitting materials were carbon FRP and Hybrid sheets which have different elastic modulus and ultimate strain capacities. Consequently, this study evaluated the structural capacity of masonry shear walls and the retrofitting effect of an FRP sheet for in-plane behavior. Also, the results were compared to the results obtained from the evaluation method for a reinforced concrete beam retrofitted with FRPs.