• Journal of the Korean Applied Science and Technology
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• v.8 no.2
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• pp.105-114
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• 1991

In relation to the preparation of Langmuir-Blodgett thin film, four kinds of N-alkylpyridiniurn bromide were synthesized. The values of surface tensions of these materials, measured with a Traube stalagmometer, gave the relationship between the critical micells hydrophobic radical and between CMC and temperature. Values of thermodynamic properties(${\Delta}H^0_m,\;{\Delta}S^0_m,\;{\Delta}G^0_m,$) for the formatoin of micelle were also obtained. Experiments gave the following results; at the temperature range between 40 and 60$^{\circ}C, CMC of Hexadecyl-, Octadecyl-, Eicosyl-, and Docosyl-Pyridinium Bromide were $7.64{\times}10^{-4}{\sim}9.13{\times}10^{-4},\;3.85{\times}10^{-4}{\sim}4.60{\times}10^{-4},\;2.00{\times}10^{-4}{\sim}2.39{\times}10^{-4},\;and\;1.07{\times}10^{-4}{\sim}1.28{\times}10^{-4}$ mol/l, respectively. Surface tension, ${\Gamma}_{CMC}$, of those were 33.49${\sim}$36.00, 34.78${\sim}$37.61, 35.49${\sim}$37.61 and 38.76${\sim}$55.80 dyne/cm, respectively, The relationship between CMC and the mumber of carbon atoms in the hydrophobic radical, N was expressed as follows : Log(CMC)=A-BN where A and B are constants. At the temperature range between 40 and 60$^{\circ}C$, the change of Gibbs evergy (${\Delta}G_m$) for one methylene group ($-CH_2-$) were -0.65RT, respectively, The minus values of enthalpy change (${\Delta}H_m$) suggest that the formation of micelle is exothermic. Additionally, the overall increase in the entropy change (${\Delta}S_m$) with respect to the temperature increase suggests that the formation of micelle is attained by a exothermic enthalpy directed process.

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.63-69
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• 1997

Micellization range and cmc for the dilute aqueous solution of sucrose monoesters, that is, sucrose monolaurate, sucrose monomyristate, sucrose monopalmitate, sucrose monostearate and sucrose monooleate were investigated by computer programming. The extreme of the curvature of ${\sigma}$(C) as a new suggested method to determine the cmc and the micellization range was accomplished with computer programming. The values of cmc and micellization range can be obtained by the extreme of the curve by direct processing of only a few experimental data. The values of cmc particulary was in good agreement with those deduced intuitively from the shape of experimental curves of ${\sigma}$(C).

• Asia pacific journal of information systems
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• v.18 no.3
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• pp.21-43
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• 2008

The task network which is formed of different individuals can be recognized as a social network. Therefore, the way to communicate with people inside or outside the network has considerable influence on their outcome. Moreover, the position on which a member stands in a network shows the different effects of the information systems supporting communication with others. In this paper, it is to be studied how personal CMC (computer-mediated communication) tools affect the mission that those who work for a network perform through diverse task networks. Especially, we focused on synchronicity of CMC. On this score, the perspective of Media Synchronicity Theory was taken that had been suggested by criticizing Media Richness Theory. It is the objective, from this perspective, to find which characteristics of networks make the value of IT supporting synchronicity high. In the research trends of social networks, there have been two traditional perspectives to explain the effect of network: embeddedness and diversity ones. These differ from the aspect which type of social network can provide much more economic benefits. As similar studies have been reported by various researchers, these are also divided into the bonding and bridging views which are based on internal and external tie, respectively, Size, density, and centrality were measured as the characteristics of personal task networks. Size means the level of relationship between members. It is the total number of other colleagues who work with a specific member for a certain project. It means, the larger the size of task network, the more the number of coworkers who interact each other through the job. Density is the ratio of the number of relationships arranged actually to the total number of available ones. In an ego-centered network, it is defined as the ratio of the number of relationship made really to the total number of possible ones between members who are actually involved each other. The higher the level of density, the larger the number of projects on which the members collaborate. Centrality means that his/her position is on the exact center of whole network. There are several methods to measure it. In this research, betweenness centrality was adopted among them. It is measured by the position on which one member stands between others in a network. The determinant to raise its level is the shortest geodesic that represents the shortest distance between members. Centrality also indicates the level of role as a broker among others. To verify the hypotheses, we interviewed and surveyed a group of employees of a nationwide financial organization in which a groupware system is used. They were questioned about two CMC applications: MSN with a higher level of synchronicity and email with a lower one. As a result, the larger the size of his/her own task network, the smaller its density and the higher the level of his/her centrality, the higher the level of the effect using the task network with CMC tools. Above all, this positive effect is verified to be much more produced while using CMC applications with higher-level synchronicity. Among the a variety of situations under which the use of CMC gives more benefits, this research is considered as one of rare cases regarding the characteristics of task network as moderators by focusing ITs for the operation of his/her own task network. It is another contribution of this research to prove empirically that the values of information system depend on the social, or comparative, characteristic of time. Though the same amount of time is shared, the social characteristics of users change its value. In addition, it is significant to examine empirically that the ITs with higher-level synchronicity have the positive effect on productivity. Many businesses are worried about the negative effect of synchronous ITs, for their employees are likely to use them for personal social activities. However. this research can help to dismiss the concern against CMC tools.

• The Korean Journal of Mycology
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• v.1 no.2
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• pp.15-23
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• 1973

Mold producing cellulase were isolated from rotten woods, and identified as the three species: Aspergillus niger van Tieghem, Aspergillus schiemanni Thom and Trichoderma viride Pers. In this paper, culture conditions in the media and characteristics of these strains were investigated. Using these strains, we have conducted a research concerning the utilization of farm product waste materia's. 1. Optimum conditions for the cellulase formation were as follows. KM 10-1; pH 5.2-5.5, $35^{\circ}C$, incubation time 6 days. OL 11-1; pH 5.5, $30-35^{\circ}C$, incubation time 6 days. SH 9-2; pH 5.5, $30^{\circ}C$, incubatoin time 6 days. 2. Their cellulase activities in their optimum condition were as follows: KM 10-1; CMC-LP 78.5% CMC-SP 4.0 glucose mg/gm of the cultures/min. OL 11-1; CMC-LP 89.9%, CMC-SP 4.9 glucose mg/gm of the cultures/min. SH 9-2; CMC-I.P 77.4%, CMC-SP 3.9 glucose mg/gm of the cultures/min. 3. Hydrolysis of animal feed containing a large quantity (23-30%) of cellulose by means of the crude enzyme in the selected strains resolved 30% of the cellulose contained in the animal feed.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.465-471
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• 2008

Highly active, stable, and magnetically separable immobilized enzymes were developed using carboxymethyl cellulose (CMC) and diethylaminoethyl cellulose DEAE-C; hereafter designated "DEAE" as supporting materials. Iron oxide nanoparticles penetrated the micropores of the supporting materials, rendering them magnetically separable. Lipase (LP) was immobilized on the surface of the supporting materials by using cross-linked enzyme aggregation (CLEA) by glutaraldehyde. The activity of enzyme aggregates coated on DEAE was approximately 2 times higher than that of enzyme aggregates coated on CMC. This is explained by the fact that enzyme aggregates with amine residues are more efficient than those with carboxyl residues. After a 96-h enantioselective ibuprofen esterification reaction, 6% ibuprofen propyl ester was produced from the racemic mixture of ibuprofen by using DEAE-LP, and 2.8% using CMC-LP.

• Membrane Journal
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• v.4 no.1
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• pp.1-8
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• 1994

There are growing needs to produce relatively high purity(99.0% or higher) oxygen at low cost. For small scale production, both pressure swing adsorption(PSA) and membrane process are competitive and less expensive or more convenient than well known cryogenic fractionation technology. A continuous membrane column(CMC) combined with a PSA oxygen generator can be employed to produce high purity oxygen continuously. The oxygen enriched gas generated by a PSA unit, with a concentration of 93~94%, is fed to the CMC that consism of three modules of poly(imide) hollow fibers. Several experiments were conducted by varying parameters, such as feed flow rate, transmembrane pressure drop, stage cut, and feed location in order to obtain a high oxygen concentration above 99.0%. A two-series unit mode was also employed with CMC operation to optimize the given membrane area.

• English Language & Literature Teaching
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• v.13 no.3
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• pp.227-251
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• 2007

The development and use of computer mediated communications (CMC) as a tool for teaching and learning English has grown considerably in recent years. The purpose of this study is to investigate factors related to learners' participation, achievement, and satisfaction in EFL classes using web-based bulletin boards. The total number of 77 university students participated in this study. Three domains and eight independent variables investigated in this study were a learner-related domain (attitudes toward CMC, intrinsic motivation, extrinsic motivation, attitudes toward writing), an interaction-related domain (student-student interaction, teacher-student interaction), and an environmental domain (physical support and design of the web site). In order to determine interrelation of variables correlation analysis and multiple regression analysis were used. The results of this study showed that the factors predicting a learner's participation were instrumental motivation, attitudes toward writing, and teacher-student interaction. The factors explaining a learner's achievement were learner's participation and attitudes toward writing, and the factors predicting a learner's satisfaction were integrative motivation, student-student interaction, teacher-student interaction, physical support and learner's participation.

• Journal of the Korean Applied Science and Technology
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• v.15 no.3
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• pp.39-45
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• 1998

In recent years, there has been considerable interest in the development of new functional surfactant including new type of anionic surfactants. Anionic surfactants, ${\alpha}-sulfo$ fatty acids that straight long chain alkyl group having from 12 to 18 carbon atoms, were synthesized with sulfur trioxide-dioxane complex to good yield. Xylitol ${\alpha}-sulfo$ fatty acid esters were obtained by reaction that the acetification and esterification of xylitol, by addition reaction with sodium chloride and hydrolysis respectively. These compounds were a new group of destructible surfactants which readily hydrolyzed and oxidized in natural water reservoirs. Physical properties of these new compounds involved surface tension, critical micelle concentration(cmc), foaming power, emulsion power, and hydrolysis properties, were measured. The cmc values of the compounds by ring method were assumed to $7.0{\times}10^{-3}{\sim}3.0{\times}10^{-2}mol/{\ell}$ range and surface tensions at cmc were $25{\sim}31dyne/cm$ respectively.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.1-5
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• 1971

1. Formation of cellulase in Myriococcum albomyces was investigated using shaking culture with addition of CMC or Avicel as an inducer to 5% wheat bran medium. 2. Three different types of cellulase fraction I, fraction II and fraction III in the culture filtrate were purified by elution column chromatography on a DEAE-Sephadex A-25. 3. By the addition of CMC as an inducer, CMCase activity was stronger than that of Avicelase. On the other hand, the addition of Avicel increased Avicelase activity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.4
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• pp.37-43
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• 2002

In recent years, numerous studies have been carried out to find out the possible substitution of PE-coated paperboards used in packaging of watery or oily foods. Accordingly, this study was carried out to obtain the basic data for producing higher functional coating agents for pulp mold by evaluating various kinds of synthetic and natural coating agents on the market. Physical properties of coated paperboards were tested. Conclusions obtained from this study were as follows. AKD and PVA showed higher functions than the other synthetic coating agents, while functions of CMC, Com starch and Oxidized starch were higher than those of other natural coating agents. Based on concentrations, AKD 0.5%, PVA 10%, CMC 1.5%, corn starch 6% and oxidized starch 8% were appeared as the proper concentrations. W3 consider that AKD may be suitable for the storage of higher moisture vegetables and other food, and PVA may be suitable for higher oily fried food.