• Elastomers and Composites
• /
• v.47 no.1
• /
• pp.23-29
• /
• 2012

The silica-silica interaction parameter (${\alpha}_F$) of the silane treated silica filled natural rubber (NR) compound was investigated. As silane (TESPT) concentration increased from 2 to 12% (2, 4, 6, 8, 10, 12%), the ${\alpha}_F$ value increased at the same silica concentration (10, 20, 30, and 40 phr). It seemed the sulfur atoms in TESPT acted as a crosslinking agent in the compound. As silica concentration increased from 10 to 40 phr, the ${\alpha}_F$ value increased at the same silane concentration due to increased silica-silica interaction.

• Journal of the Society of Naval Architects of Korea
• /
• v.50 no.1
• /
• pp.1-7
• /
• 2013

The high-skewed and/or composite propellers of current interests to reduce the ship vibration and to increase the acoustic performance are likely to be exposed to the unexpected structural problems. One typical example is that the added mass effect on the propellers working in the non-uniform wake field reduces the natural frequency of the propeller leading to the resonance with the low-frequency excitation of the external forces. To avoid this resonance problem during the design stage, the technique of fluid-structure interaction has been developed, but the higher-order effect of the blade geometry deformation is not yet considered in evaluating the added mass effects. In this paper the fluid boundary-value problem is formulated by the potential-based panel method in the inviscid fluid region with the velocity inflow due to the body deformation, and the structural response of the solid body under the hydrodynamic loading is solved by applying the finite element method which implements the 20-node iso-parametric element model. The fluid-structure problem is solved iteratively. A basic fluid-sturcture interaction study is performed with the simple rectangular plates of thin thickness with various planform submerged in the water of infinite extent. The computations show good correlation with the experimental results of Linholm, et al. (1965).

• Archives of design research
• /
• v.17 no.3
• /
• pp.147-156
• /
• 2004

Currently, usability tests for web sites with representative users are conducted in laboratory environment that disturbs subjects' natural behavior. These test methods are inefficient for tests that require large number of subjects, because experimenters and subjects should be located in the same place at the same time during the test. In this study, a remote usability test tool, called 'RIO' has been developed to cope with these laboratory-based experiment problems - the 'synchronism' and the 'unnatural environment'. The tool is separated into three parts: 'Project Manager', 'Remote Interaction Observer', and 'Interaction Analyzer'. 'Project Manager' sets up overall experimental parameters and actual tasks to be peformed by subjects. 'Remote Interaction Observer', endued with Microsoft Internet Explorer Control, is a modified Web Browser which records user interactions, screen images and elaborate browser events while subject performs given tasks. This module is distributed to subjects as an installable software package. When they finish all the tasks, the captured interaction data is compressed and sent to 'Interaction Data Server' automatically. 'Interaction Analyzer' visualizes interaction data from the 'Interaction Data Server'. It also generates project-scope statistics which facilitate discovering peculiar cases among interaction submissions.

• Structural Engineering and Mechanics
• /
• v.12 no.2
• /
• pp.189-200
• /
• 2001

This paper presents an experimental modal analysis of perforated rectangular plates in air or in contact with water. The penetration of holes in the plates had a triangular pattern with P/D (pitch to diameter) 2.125, 2.500, 3.000 and 3.750. The plate was clamped along the plate edges by a number of bolts and nuts. The natural frequencies of the perforated plates in air were obtained by the analytical method based on the relation between the reference kinetic and maximum potential energies and compared with the experimental results. Good agreement between the results was found for the natural frequencies of the perforated plates in air. Additionally, it was empirically found that the natural frequencies of the perforated plate in air increase with an increase of P/D, on the other hand, the natural frequencies of the perforated plate in contact with water decrease with an increase of P/D.

• Animal cells and systems
• /
• v.6 no.3
• /
• pp.263-269
• /
• 2002

The p53 tumor suppressor gene is among the most frequently mutated and studied genes in human cancer, but the mechanisms by which it sur presses tumor formation remain unclear. DNA damage regulates both the protein levels of p53 and its affinity for specific DNA sequences. Stabilization of p53 in response to DNA damage is caused by its dissociation from Mdm2, a downstream target gene of p53 and a protein that targets p53 for degradation in the proteosome. Recent studies have suggested that phosphorylation of human p53 at Ser20 is important for stabilizing p53 in response to DNA damage through disruption of the interaction between Mdm2 and p53. We generated mice with an allele encoding changes at Ser20, known to be essential for p53 accumulation following DNA damage, to enable analyses of p53 stabilization in vivo. Our data showed that the mutant p53 was clearly defective for full stabilization of p53 in response to DNA damage. We concluded that Ser20 phosphorylation is critical for modulating the negative regulation of p53 by Mdm2, probably through phosphorylation-dependent inhibition of p53-Mdm2 interaction in the physiological context.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1579-1582
• /
• 2009

The reaction rates of 4-X-2,6-dinitrochlorobenzenes (X = $NO_2,\;CN,\;CF_3$) with Y-substituted pyridines (Y = 3-$OCH_3,\;H,\;3-CH_3,\;4-CH_3$) in methanol-acetonitrile mixtures were measured by conductometry at 25 ${^{\circ}C}$. It was observed that the rate constant increased in the order of X = 4-$NO_2\;>\;4-CN\;>\;4-CF_3$ and the rate constant also increased in the order of Y = 4-$CH_3\;>\;3-CH_3\;>\;H\;>\;3-OCH_3$. When the solvent composition was varied, the rate constant increased in order of MeCN > 50% MeOH > MeOH. The electrophilic catalysis by methanol may be ascribed to the formation of hydrogen bonds between alcoholic hydrogen and nitrogen of pyridines in ground state. Based on the transition parameters, ${\rho}_S,\;{\rho}_N,\;{\beta}_Y,\;{\rho}_{XY}$ and solvent effects, the reaction seems to proceed via $S_N$Ar-Ad.E mechanism. We also estimated the isokinetic solvent mixtures (${\rho}_{XY}$ = 0) based on cross-interaction constants, where the substituent effects of the substrate and nucleophile are compensated.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.734-742
• /
• 2016

Global warming and the depletion of fossil fuels have been caused by decades of reckless development. Wind energy is one form of renewable energy and is considered a future energy source. The wind tower is designed with a fundamental frequency in the soft-stiff design between the 1P and 3P range to avoid resonance. Usually, to perform natural frequency analysis of a wind tower, the boundary condition is set to the Fixed-End, and soil-pile interaction is not considered. In this study, consideration of the effect of soil-pile interaction on the wind tower was included and the difference in the natural frequency was studied. The fixed boundary condition was not affected by the soil condition and depth of the pile and the coupled spring boundary condition was unaffected by the depth of pile but affected by the depth of the pile, and the Winkler spring boundary condition is affected by both the soil condition and the depth of the pile. Therefore, the coupled spring boundary condition should be used in shallow depth soil conditions because the soil condition does not take the shallow depth soil into consideration.

• The Journal of Natural Sciences
• /
• v.17 no.1
• /
• pp.13-29
• /
• 2006

Most redox-active proteins have thiol-bearing cysteine residues that are sensitive to oxidation. Cysteine thiols oxidized to sulfenic acid are generally unstable, either forming a disulfide with a nearby thiol or being further oxidized to a stable sulfinic acid, which have been viewed as an irreversible protein modification. However, recent studies showed that cysteine residues of certain thiol peroxidases (Prxs) undergo reversible oxidation to sulfinic acid and the reduction reaction is catalyzed by sulfiredoxin (Srx1). Specific Cys residues of various other proteins are also oxidized to sulfinic acid ($Cys-So_2H$). Srxl is considered one of the oxidant proteins with a role in signaling through catalytic reduction of oxidative modification like in the reduction of glutathionylation, a post-translational, oxidative modification that occurs on numerous proteins. In this study, the role of sulfiredoxin in cellular processes, was investigated by studying its interaction with other proteins. Through the yeast two-hybrid system (Y2HS) technique, we have found that Ams1 is a potential and novel interacting protein partner of Srxl. $\alpha$-mannosidase (Ams1) is a resident vacuolar hydrolase which aids in recycling macromolecular components of the cell through hydrolysis of terminal, non-reducing $\alpha$-D-mannose residues. It forms an oligomer in the cytoplasm and under nutrient rich condition and is delivered to the vacuole by the Cytoplasm to Vacuole (Cvt) pathway. Aside from the role of Srxl as a catalyst in the reduction of cysteine sulfenic acid groups, it may play a completely new function in the cellular process as indicated by its interaction with Ams1 of the yeast Saccharomyces cerevisiae.

• Journal of Broadcast Engineering
• /
• v.20 no.1
• /
• pp.110-121
• /
• 2015

The digital app-book is an advanced form of the electronic book (e-book), which attracts a lot of interests by the help of video, sound, sensors and a variety of interactions. As mobile devices have evolved, the demand of digital app-books is also rising substantially. However, the distribution of digital app-book contents is hard to meet the demand because the digital app-book requires a lot of programming cost for the interaction. To resolve this problem, Was verified and implementation as a library function of the interaction between device and user. The proposed library consists of three parts (user action recognition, device action, and content action) and provides various user-device interaction functions by combining methods of each part, which can support source code reusability, easy understanding and availability, and wide expandibility. The library was used in the development of natural science education app-book contents. As a result, it could reduce a lot of code lines and facilitate more rapid app-book development.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.2
• /
• pp.201-204
• /
• 2002

The rates of the aminolysis of S-phenyl substituted-acetate series $(RC(=O)SC_6H_4Z$, with R=Me, Et, i-Pr, t-Bu and Bn) with benzylamines $(XC_6H_4CH_2NH_2)$ are not correlated simply with the Taft's polar $({\sigma}^{\ast})$ and/or steric effect constants $(E_s)$ of the substituents due to abnormally enhanced rate of the substrate with R=Et. Furthermore, the cross-interaction constant, ${\rho}x_z$ , is the largest with R=Et. These anomalous behaviors can only be explained by invoking the vicinal bond $({\sigma})$-antibond $({\sigma}^{\ast})$ charge transfer interaction between C-$C{\alpha}$ and C-S bonds. In the tetrahedral zwitterionic intermediate, $T^{\pm}$ , formed with R=Et the vicinal ${\sigma}_{c-c}-{\sigma}^{\ast}_{c-s}$ delocalization is the strongest with an optimum antiperiplanar arrangement and a narrow energy gap, ${\Delta}{\varepsilon}={\varepsilon}_{{\sigma}^{\ast}}-{\varepsilon}_{\sigma}$. Due to this charge transfer interaction, the stability of the intermediate increases (with the concomitant increase in the equilibrium constant K (= $k_a/k_{-a}$)) and also the leaving ability of the thiophenolate leaving group increases (and hence $k_b$ increases) so that the overall rate, $k_n\;=\;Kk_b$, is strongly enhanced. Theoretical support is provided by the natural bond orbital (NBO) analyses at the B3LYP/6-31+$G^{\ast}$ level. The anomaly exhibited by R=Et attests to the stepwise reaction mechanism in which the leaving group departure is rate limiting.