• Korean Journal of Materials Research
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• v.28 no.5
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• pp.308-314
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• 2018

Among the fuel cell electrolyte candidates in the intermediate temperature range, glass materials show stable physical properties and are also expected to have higher ion conductivity than crystalline materials. In particular, phosphate glass has a high mobility of protons since such a structure maintains a hydrogen bond network that leads to high proton conductivity. Recently, defects like volatilization of phosphorus and destruction of the bonding structure have remarkably improved with introduction of cations, such as Zr4+ and Nb5+, into phosphate. In particular, niobium has proton conductivity on the surface because of higher surface acidity. It can also retain phosphorus content during heat treatment and improve chemical stability by bonding with phosphorus. In this study, we fabricate niobium phosphate glass thin films through sol-gel processing, and we report the chemical stability and electrical properties. The existence of the hydroxyl group in the phosphate is confirmed and found to be preserved at the intermediate temperature region of $150-450^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1485-1489
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• 2003

The gelation for di-(2-ethylhexyl) phthalate (DEHP)-plasticized poly(vinyl chloride) was studied by measuring time-resolved small-angle X-ray scattering (SAXS) and a flow of the solutions in test tube. It was found that for the gelation there were three regimes. At Regime I, the solution rapidly changed to a gel, and the SAXS intensity showed a peak and the peak intensity increased, keeping the peak angle constant. Applying the SAXS intensity to the kinetic analysis of the liquid-liquid phase separation, it was revealed that the spinodal decomposition proceeded to develop a periodic length of 29.9 nanometer in size, a hydrogen-bonding-type association in polymer rich phase followed, and then it induced fast gelation rate. At Regime II, the gelation slowly occurred and the SAXS intensity was not observed, suggesting that a homogeneous gel network was formed by a hydrogen-bonding. At regime III, the solution was a homogeneous sol.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.5
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• pp.421-429
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• 2022

Entrepreneurship research has focused on several factors that might affect the intention of an individual to start an enterprise. Using principles from social network theory and the entrepreneurial intention model (EI), the current research intends to investigate how social capital is formed on Social Networking Sites (SNS) and how the resulting social capital influences entrepreneurial intention. Using an online survey, 151 valid responses were received from university students. Applying partial least square structural equation modeling, positive and significant relationship was found between the SNS usage and bonding and bridging social capital. Further, it was also found that online-bonding social capital does not impact any of the three antecedents of entrepreneurial intention. On the other hand, online-bridging social capital significantly influences personal attitudes and subjective norms. It was also found that both personal attitude and perceived behavioral control significantly relate to EI, while the subjective norms do not relate significantly to EI. The paper contributes to the literature on technology-based human behavior and entrepreneurship in emerging countries, opening some areas for future research, while also providing some managerial insights. It also should be beneficial to educational institutions in understanding how the use of SNS use by students may be optimized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.69-72
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• 2007

DOCSIS 3.0 Protocol is proposed to make the advance of HFC network. In the DOCSIS based network, the upstream frame is divided into contention section reservation section. CMs to have packets send request messages through the contention section. That two or more CMs sends Request message at the same contention slot makes collison. In this paper, are propose the contention section establlish at algorithm considering of channel-bonding mechanism that is the primary technique of DOCSIS 3.0. Results of simulation display better performance int the number of contention slots and the utilization of contention section.

• The Journal of Information Systems
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• v.27 no.2
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• pp.135-155
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• 2018

Purpose Recently, with the enhancement of mobile technologies, people have formed various relationships and spreaded networks on social network service(SNS). In addition, although people make a decision based on the thoughts and emotions about self, there is little empirical research on social relations and self-construal of users in social network game (SNG). Design/methodology/approach This study was designed to examine the structural relationships among SNG users' social capital, self-construal, behavioral adaptation, SNG reuse intention and charged item purchasing intention. Findings The results from this study are as follow. First of all, the bonding social capital did not have a significant impact on behavioral adaptation to SNG, but bridging social capital had a positive impact on behavioral adaptation. Second, independent self-construal did not have a significant impact on behavioral adaptation to SNG, but interdependent self-construal had a positive impact on behavioral adaptation. Lastly, the behavioral adaptation to SNG had a positive impact reuse intention and charged item purchasing intention. Also, SNG reuse intention had a positive impact on charged item purchasing intention.

• Molecules and Cells
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• v.25 no.3
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• pp.352-357
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• 2008

Osteoprotegerin (OPG) is a soluble decoy receptor that inhibits osteoclastogenesis and is closely associated with bone resorption processes. We have designed and determined the solution structures of potent OPG analogue peptides, derived from sequences of the cysteine-rich domain of OPG. The inhibitory effects of the peptides on osteoclastogenesis are dose-dependent ($10^{-6}M-10^{-4}M$), and the activity of the linear peptide at $10^{-4}M$ is ten-fold higher than that of the cyclic OPG peptide. Both linear and cyclic peptides have a ${\beta}$-turn-like conformation and the cyclic peptide has a rigid conformation, suggesting that structural flexibility is an important factor for receptor binding. Based on structural and biochemical information about RANKL and the OPG peptides, we suggest that complex formation between the peptide and RANKL is mediated by both hydrophobic and hydrogen bonding interactions. These results provide structural insights that should aid in the design of peptidyl-mimetic inhibitors for treating metabolic bone diseases caused by abnormal osteoclast recruitment.

• Elastomers and Composites
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• v.45 no.3
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• pp.165-169
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• 2010

Recently supramolecular network thermo-reversible crosslinking elastomer having flexibility, various functionality, and advantages of thermoplastic elastomer (TPE) such as recycle and easy processbility is introduced. Although thermo-reversible bonds such as hydrogen bond and ionic cluster is recognized as a common technology since 1990, control technology of bonding and dissociation of crosslink in supramolecular network is a recent technology. In this review, characteristics of thermo-reversible crosslinking elastomer having rheological properties of TPE and reinforcing behaviors of thermoset elastomer are summarized.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.1-8
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• 2001

Paper consists of fiber network and paper properties were highly affected by fiber characteristics. Many researchers have tried to relate fiber and paper properties. Softwood and hardwood fiber's are quite different in their properties. Generally, softwood fiber's are longer and more flexible than hardwood fibers. At present, many paper mills make mixed paper with softwood and hardwood fibers except for special grade. During fracture some fiber's are broken and others are pulled out. In this paper, the number of broken and pulled out fiber's during fracture is analyzed depending on the mixing ratio of softwood and hardwood fiber's. Fiber length, curl, kink, coarseness, WRV and formation index were measured. Double-edged strength samples were prepared to observe the number of broken and pulled out fiber's. Mixed paper strength was decreased with increasing hardwood fibers ratio. During fracture, softwood fiber's were more likely broken and hardwood fibers were more likely pulled out. The strength of paper which consists of softwood fibers was determined by fiber's broken strength and that of hardwood fibers by fiber's debonding strength. Paper strength was changed depending on the fiber's bonding capability. If the fiber is longer and more flexible, the fiber network becomes stronger and stiffer.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.193-202
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• 2016

Purpose: This study was performed in order to assess the effect of the surface treatment methods and the use of bonding agent on the shear bond strength (SBS) between the aged CAD-CAM (computer aided design-computer aided manufacturing) hybrid materials and added composite resin. Materials and methods: LAVA Ultimate (LU) and VITA ENAMIC (VE) specimens were age treated by submerging in a $37^{\circ}C$ water bath filled with artificial saliva (Xerova solution) for 30 days. The surface was ground with #220 SiC paper then the specimens were divided into 9 groups according to the combination of the surface treatment (no treatment, grinding, air abrasion with aluminum oxide, HF acid) and bonding agents (no bonding, Adper Single Bond 2, Single Bond Universal). Each group had 10 specimens. Specimens were repaired (added) using composite resin (Filtek Z250), then all the specimens were stored for 7 days in room temperature distilled water. SBS was measured and the fractured surfaces were observed with a scanning electron microscope (SEM). One-way ANOVA and Scheffe test were used for statistical analysis (${\alpha}=.05$). Results: Mostly groups with bonding agent treatment showed higher SBS than groups without bonding agent. Among the groups without bonding agent the groups with aluminum oxide treatment showed higher SBS. However there was no significant difference between groups except two subgroups within LU group, which revealed a significant increase of SBS when Single Bond Universal was used on the ground LU specimen. Conclusion: The use of bonding agent when repairing an aged LAVA Ultimate restoration is recommended.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.7
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• pp.18-25
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• 2014

To increase wireless capacity, the concurrent use of multiple wireless interfaces on different frequency bands, called aggregation, can be considered. In this paper, we focus on aggregation of multiple Wi-Fi interfaces with packet-level traffic spreading between the interfaces. Two aggregation schemes, link bonding and multipath TCP (MPTCP), are tested and compared in a dualband Wi-Fi radio system with their Linux implementation. Various test conditions such as traffic types, network delay, locations, interface failures and configuration parameters are considered. Experimental results show that aggregation increases throughput performance significantly over the use of a single interface. Link bonding achieves lower throughput than MPTCP due to duplicate TCP acknowledgements (ACKs) resulting from packet reordering and filtering such duplicate ACKs out is considered as a possible solution. However, link bonding is fast responsive to links' status changes such as a link failure. It is shown that different combinations of interface weights for packet spread in link bonding result in different throughput performance, envisioning a spatio-temporal adaptation of the weights. We also develop a mathematical model of power consumption and compare the power efficiency of the schemes applying different power consumption profiles.