• Journal of Information Management
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• v.33 no.2
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• pp.49-66
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• 2002

In this paper, the recent trends of user-centered information communication are reviewed, especially focused on Computer-Mediated Communication(CMC) based on internet, Human Factors Engineering, and Human-Computer Interaction(HCI). The result is that human-centered information communication process has influence on the extension of user interface.

• Bulletin of the Korean Chemical Society
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• v.7 no.5
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• pp.399-402
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• 1986

The critical micelle concentration (CMC) of sodium deoxycholate (NaDC) and the effects of amides on the micellization processes have been studied by fluorometric technique using pyrene as a probe. The addition of amides as cosolvent destabilized the NaDC micelle and increased the CMC. The order of effectiveness for the perturbation of NaDC micelle was N-methylacetamide ${\ge}$ DMF > acetamide > formamide, which is the order of hydrophobicity of the amines. This indicated that the effect of amides on the micellization processes of NaDC arises from diminution of the hydrophobic effect. The electrostatic repulsion between ionic head groups in the NaDC micelle appeared to be much less than that in aliphatic ionic micelle. This was also revealed in the weaker dependence of the CMC on ionic strength. The premicellar association of NaDC was not significantly involved in the micellization processes of the bile salt.

• Archives of Pharmacal Research
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• v.15 no.2
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• pp.126-129
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• 1992

The critical micelle concentrations (CMCs) of aqueous solutions of a nonionic surfactant, polyoxyl 23 lauryl ether in the presence of various concentration of urea and its derivatives were measured. The CMC of the surfactant increase in proportion to the concentration of the additives, and the CMC-raising activities increased with more and longer alkyl grups substituted in urea. The CMC shift values were successfully correlated with the cloud point shift values and the protein-denaturing activities of the additives, respectively. These results suggest that the micelle formation, clouding of the surfactant and the protein denaturation are a closely related phenomenon, and a common mechanism is operating which might be the hydrophobic interaction.

• Journal of Distribution Science
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• v.13 no.2
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• pp.75-83
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• 2015

Purpose - This study aims to identify the effects of communication cues, anonymity, and social presence on group polarization in computer-mediated communication (CMC) settings. Extant literature has introduced some theoretical backgrounds of social presence and SIDE (Social Identity model of Deindividuation Effects) to explain the effects of communication cues and anonymity. The concept of social presence emphasized the mediating role on communication cues and anonymity. However, most literature did not measure social presence and compare group polarization of all condition groups. This does not sufficiently explain the result of group polarization. Research design, data, and methodology - We believe that the direct impact of anonymity on group polarization can provide a more admissible and clearer explanation for the results. In addition, this study categorizes anonymity into two levels, as anonymity of group and anonymity of self. To justify the anonymity view, a laboratory experiment was conducted. The experiment was conducted in communication cues settings (visual cue; without visual cue) and anonymity settings (identified; anonymous). Each of the four settings has 10 groups consisting of five subjects each (total 200 subjects). The subjects are undergraduates from a large university, majoring in business. All experimental procedures and calculations of choice shift and preference change follow the literature. Results - First, the removal of visual cues does not produce a significant impact on group polarization, which cannot be explained by the social presence view. Second, the anonymous condition does not significantly affect group polarization, which also cannot be explained by the social presence view. However, the anonymous condition directly affects group polarization. Specifically, anonymity of self has a stronger effect on group polarization than anonymity of group. The result explains about the leading factor affecting group polarization. This study examines another view of how computer-mediated communication may be associated with group polarization. The process and outcome data from the experiment reveal that group polarization is not affected by level of social presence, but by level of anonymity. Group discussions conducted with visual cue CMC setting and identified CMC setting result in weaker group polarization. Conversely, group discussions conducted without visual cue CMC setting and anonymous CMC setting lead to stronger group polarization. The results of the study have the following implications. First, they provide clues for business organizations to design the most appropriate media conditions and preemptive social conditions to implement when making group decisions through CMC, to maximize achievements, generate amicable agreements, or actively share information. Second, this study can be useful in analyzing different adverse effects generated through Internet use. Conclusions - This research can help explain discussions and decision-making actions on Internet forums, which have recently increased, as well as providing a foundational basis in newly establishing policies for the forums. Finally, it should be noted that many other factors such as group size, topics, and group history may affect group polarization. These should be examined in future studies.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.281-288
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• 2016

Purpose: The present study was aimed to investigate the change of optical quality in fully cured eyes from central serous chorioretionopathy(CSC) and CSC under treatment, respectively. Methods: A total of 136 eyes(68 subjects) was divided into CMC under treatment and its asymptomatic contralateral eye, fully cured eyes after being diagnosed with CMC and its contralateral eye, and normal eyes. Objective scattering index, cut-off value in modulation transfer function, focusing rate, PSF(Point Spread Function) width at 50%, 10% and the contrast sensitivity were measured and analyzed. Results: CMC under treatment showed statistically significant decrease in all evaluations of optical quality compared with asymptomatic contralateral eyes, fully cured eyes and normal eyes. Although there was no significant difference in optical quality between asymptomatic contralateral eyes of CMC under treatment and fully cured eyes, there was tendence in optical quality decreasing compared with normal eyes. Conclusions: From the study, it was revealed that the optical quality was different according to the treatment phase in CMC. The use of optical quality assessment for the decision of complete cure and the evaluation of prognosis in CMC is also proposed.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.31-37
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• 2009

A zwitterionic surfactant shows not only detergency but also mildness effect since it shows characteristics of a nonionic or an anionic surfactant above an isoelectric point, while showing characteristics of a cationic surfactant below an isoelectric point. Therefore, a zwitterionic surfactant can serve as a dual function surfactant by a single molecule through the interconversion of cleaning and softening effects depending on pH variations of the aqueous solution. In this study, physical properties of betaine surfactant such as CMC, surface tension, interfacial tension, contact angle and viscosity were measured and phase behavior study was performed. Also dual function characteristics of betaine zwitterionic surfactant were investigated by measuring an isoelectric point using QCM(quartz crystal microbalance) and zeta potential measurement. The CMC of betaine surfactant was near $10^{-4}mol/L$ and the surface tension at CMC was about 32 mN/m. The interfacial tension between 1 wt% aqueous solution and n-decane measured by spinning drop tensiometer at pH 2~10 resulted in an increase in interfacial tension until pH 5 and a decrease with pH after 5 and equilibration time showed the similar trend with an increase in pH. The isoelectric point of betaine surfactant measured by QCM experiment was found to exist between 3.0 and 3.3, which is the same as the result determined by zeta potential measurement.

• Clean Technology
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• v.22 no.4
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• pp.258-268
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• 2016

In this work, carboxymethylcellulose-based composite superabsorbent hydrogels were prepared by electron beam radiation. The composition of carboxymethylcellulose (CMC) varied from 4 wt%, 5 wt%, and 6 wt% to 7 wt% based on the amount of distilled water in the syntheses of hydrogels. Graphite oxide, reduced graphene oxide, activated carbon, and bentonite were used as additives for the synthesis of composite superabsorbent. The effect of CMC composition and the type of additives on the gel properties of the prepared hydrogels was investigated. In order to verify the functional groups in the prepared materials, Fourier transform infrared spectroscopy was used. In addition, mechanical strength, gel fraction, swelling kinetics, and equilibrium swelling ratios were measured for the prepared hydrogels. Swelling experiments were carried out in distilled water, urea solution, and physiological saline water. Prepared hydrogels were reused for 5 times, and gel fraction and swelling ratio were measured at every 24 hours. Among the prepared hydrogels, $C_{5%}GO$ and $C_{5%}rGO$ exhibited excellent mechanical property and relatively high swelling ratios for urea solution and physiological saline water with promising applicability as slow-release fertilizers.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.65-74
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• 1998

To enhance the washing efficiency of soil polluted by hydrophobic organic compounds, the effects of electrolytes and monomeric organic additives on micelle formation and washing efficiency of mixed surfactant solutions were investigated in this study. The surface tensions and critical micelle concentrations(CMCs) of the single and mixed surfactant solutions[$POE_5$/SDS] supplemented by NaCl were measured to investigate the effects on washing efficiency, and the composition ratios of surfactants and NaCl were optimized for the efficient soil washing system. As the mixing ratio of $POE_5$/SDS was increased to 80%, the mixed surfactant with 0.01M NaCl showed more proportional increase of washing efficiency than the mixed surfactant without any salts. The 3% solution of $POE_5$ and SDS(80%/2o%) with 0.01M NaCl showed the washing efficiency of 90%. However, the washing efficiency was not enhanced by NaCl addition to the single surfactant solution of $POE_5$. The CMC of SDS(0.049%) was higher than that of $POE_5$(0.016%), but the CMCs of mixed surfactants were decreased as the mixing ratio of $POE_5$ was increased. Alcohols having longer chain and branched carbon chain were found to be desirable for the soil washing additives.

• Journal of the Korean Society of Safety
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• v.9 no.3
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• pp.67-73
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• 1994

The gas holdup and volumeteric liquid phase mass transfer coefficient with the variation of the concentration of CMC aqueous solution, gas velocity, diameter and area of the draught tube were investigated. As the results of the experiments, the gas holdup and volumetric liquid phase mass transfer coefficient decreased with decreasing the concentration of CMC aqueous solution, increased with increasing the gas velocity and increased with increasing the circulated area ratio of the draught tube.

• Bulletin of the Korean Mathematical Society
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• v.58 no.5
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• pp.1053-1068
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• 2021

We investigate the spacelike hypersurface Mⁿ with constant mean curvature (CMC) in a Lorentz Einstein manifold Lⁿ⁺¹₁, which is supposed to obey some appropriate curvature constraints. Applying a suitable Simons type formula jointly with the well known generalized maximum principle of Omori-Yau, we obtain some rigidity classification theorems and pinching theorems of hypersurfaces.