• Bulletin of the Korean Chemical Society
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• v.16 no.4
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• pp.305-309
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• 1995

The enantiomeric separation of several amino acid derivatives by reversed-phase liquid chromatography using two (R)-and (S)-naphthylethylcarbamate-β-cyclodextrin(NEC-β-CD) bonded stationary phases was studied to illustrate the chiral recognition model of the enantiomeric separation. The retention and enantioselectivity of the chiral separations with (R)-and (S)-NEC-β-CD bonded phases were compared with similar separations with the native β-CD stationary phases. Especially, the enantioselectivity and elution orders between the derivatized amino acid enantiomers are carefully examined. These results can be illustrated by the chiral recognition models involving inclusion complexation, π-π interaction, and/or hydrophobic interaction. Inclusion complexation and hydrophobic interaction of the naphthyl group of the NEC moiety seem to be major chiral recognition components in the enantiomeric separation of 2,4-dinitrophenyl amino acids and dabsyl amino acids on (R)-and (S)-NEC-β-CD columns. For dansyl amino acids, only the inclusion complexation is the dominant factor. Three different chiral recognition models containing π-π interaction, inclusion complexation and hydrogen bonding were proposed for the separation of the 3,5-dinitrobenzoyl amino acid enantiomers, depending on the size and shape of amino acids.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.405-416
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• 1995

The testis and the epididymis of sexually mature male bats were examined to investigate the process of spermiogenesis of Korean long-fingered bat (Miniopterus schreifersi fulignosus) using electron microscope. The ultrastructural findings were analysed on the basis of Lee's method (1992). Especially, we focused on the acrosome formation. The results are as follows: The spermiogenesis of the Korean long-fingered bat can be divided into ten phases on the basis of ultrastructural differentiation; three "Golgi" phases of early, mid and late stages, two "cap" and two "acrosome" phases respectively composed of early and late phases, one "maturation phase and two "spermiation" phases of early and late phases. The axoneme of sperm in the cauda epididymis is composed of nine outer dense fiber and a central singlet. The number 1, 5, 6, and 9 outer dense fibers are larger than others. In the Golgi phases, small vesicles are separated from Golgi vesicles and then appear to fuse into a large vesicle, and finally it contacd with the outerside of the nucleus. It suggests that proacrosomal material could be made in the cytoplasm before the Golgi vesicle formation and then it could be transferred into the Golgi vesicle and condensed more and more, and finally form acrosome, just as Lee;s suggestion (1992).m acrosome, just as Lee;s suggestion (1992).

• Korean Journal of Materials Research
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• v.19 no.2
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• pp.111-114
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• 2009

For the fabrication of core-shell structure bimetallic lead-free solder balls, both the critical temperature ($T_{cr}$) for the phase separation of two immiscible liquid phases and the temperature coefficient of the interfacial tension between the two separated liquid phases are required. In order to obtain this information, the temperature dependence of the surface tension of 60%Bi-24%Cu-16%Sn(-REM) alloys was measured using the constrained drop method. The slope of the temperature dependence of the surface tension changed clearly at a critical temperature for the separation of two immiscible liquid phases. The critical temperature of the 60%Bi-24%Cu-16%Sn alloy was estimated to be 1097K. An addition of 0.05% Ce decreased the critical temperature to 1085K, whereas that of 0.05% La increased it to 1117K. It was found that the surface tension and its temperature coefficient of the 60%Bi-24%Cu-16%Sn alloy were slightly increased by the addition of 0.05% Ce and 0.05% La. In addition, additions of Ce and La increased the temperature coefficient of the interfacial tension.

• Journal of information and communication convergence engineering
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• v.19 no.1
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• pp.42-47
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• 2021

Multimedia Authoring Tool is a tool for creating multimedia presentations. With this tool, a user can produce playable multimedia documents. A Multimedia Authoring Tool requires input in the form of a spatial layout and a temporal layout. Users can make many mistakes in creating multimedia presentations and verification is required in the Multimedia Authoring process in order to produce multimedia documents. In this study, two verification phases are proposed: Time Computation and Spatiotemporal Conflict Verification. In the experiment conducted for this study, two kinds of verification were carried out: The use of single-phase verification and the use of double-phase verifications. By using these two types of verification, it became easier to successfully detect errors in the spatial and temporal layouts, and the types of verification have also been successful in increasing the success of error detection.

• Applied Microscopy
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• v.26 no.2
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• pp.221-233
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• 1996

In order to study process of spermiogenesis of the Korean manchurian field mouse, Apodemus spesiosus peninsulae, the testis obtained from sexually matured male reproductive organs, were examined with electron microscopy, and the following results were obtained based on the characters of cell differentiation. 1. According to the features of cell structure, spermiogenesis of the Apodemus spesiosus peninsulae was five phases: Golgi, cap, acrosome, maturation and spermiation phase. They were further subdivided into two steps of early and late phases respectively. Hence, the spermiogenesis consists of ten steps. 2. In the changes of the chromatin, the chromatin granules began to be condenced in the cap phase and regularizated at maturation phases, and a perfect nucleus of sperm was formed at the spermiation phases. 3. The formative period of sperm tail began to be develop in the early Golgi phase and completed at the spermiation phases 4. The outer dence fibers of middle piece were arranged in a horseshoe fashion. Nos. 1, 5, 6 and 9 of the outer dense fibers were larger than the others. The structure of axoneme in the middle piece was 9+2, and the axonemal complex consists of A and B microtubules, dynein arms and radial links.

• Journal of the Korean Solar Energy Society
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• v.21 no.2
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• pp.69-78
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• 2001

This paper introduces the physical phenomena involved in Direct Contact Heat Exchangers (DCHXs) and also investigates the possibility of applying of EIT(Electrical Impedance Tomography) technique for capturing the images of dispersed phases as they stream through a stagnant body of water. A number of cases are studied where two dimensional cross-sectional static images are given for fictitious and actual masses present in a column of water(saline solution). In most direct contact liquid-liquid heat exchangers, oil or hydrocarbon with a density different(lighter or heavier) from water is normally used as dispersed working fluid. The main difficulty that arises with this arrangement lies in the elucidation of complicated flow field where the dispersed phase fluid tends to change its shape and size constantly during its journey through the other phase(water). This paper presents a number of results with different types of dispersed phases that are immiscible with water. The EIT technique has been employed in this context to test its applicability in capturing the dynamic images of dispersed phases. It shows static images of dispersed phases where dynamic images could be obtained by simply extending the algorithms and strategies employed in the present analysis.

• Applied Microscopy
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• v.25 no.1
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• pp.96-110
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• 1995

In order to clarify the process of spermiogenesis of the large-footed bat, Myotis macrodactylus, the testis and the epididymis obtained from mature male bats were examined by electron microscope. Based on the variety and diagnostic characters of organells, the spermiogenesis of the large-footed bat. Myotis macrodactylus could be divided into a total of nine phases. The results obtained from the present study are as follows. 1. The spermiogenesis of large-footed bat, Myotis macrodactylus was divided according to the level of fine structural differentiation into five phases, Golgi, cap, acrosome, maturation and spermiation phases, respectively; Golgi, cap, acrosome and spermiation phases were further subdivided into steps of early and late phase respectively and maturation phase has only one step. Hence, the spermiogenesis of the large-footed bat has been divided into a total of nine phases. 2. In the change of chromatin with nucleus, the chromatin granules are condensed in the whole part of nucleus at the late Golgi phase and completed at the maturation phase. 3. The sperm tail in the epididymis consists of nine outer doublets and two central singlet microtubles. Nos. 1, 5, 6, 9 of the outer dense fibers were larger than the others (2, 3, 4, 7, 8).

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.575-579
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• 2013

1,3-Propandiol is a promising chemical which can be produced from fermentation of glycerol because the application of 1,3-propanediol is mainly in the production of bio-polytrimethylene terephthalate (bio-PTT). However, the cost of downstream processes in the biological production of 1,3-propanediol can make a high portion in the total production cost due to the large amount of water and the by-produced carboxylic acids such as succinic, lactic and acetic acids in 1,3-propanediol fermentation broth. In this study, aqueous two-phases systems composed of hydrophilic alcohols and phosphate salts were applied to the recovery of 1,3-propanediol from its artificial aqueous solution. Formation of aqueous biphases in hydrophilic alcohols and phosphate salts was due to the salting-out effect of salts in bottom phase, thereby 1,3-propanediol in bottom phase was moved into top phase. Extraction efficiency for 1,3-propanediol was proportional to the polarity of hydrophilic alcohols and the basicity of salts and the maximum value of extraction efficiency was more than 98%. In the aqueous two-phases systems after extraction, there was no carboxylic acid in top phase. Therefore, it was concluded that the aqueous two-phases systems composed of hydrophilic alcohols and phosphate salts were effective for the selective recovery of 1,3-propanediol without any coextraction of carboxylic acids.

• Physical Therapy Korea
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• v.31 no.1
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• pp.40-47
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• 2024

Background: Single-leg squat (SLS)s are commonly used as assessment tool and closed kinetic exercises are useful for assessing performance of the lower extremities. Pronated feet are associated with foot pressure distribution (FPD) during daily activities. Objects: To compare the FPD during SLSs between groups with pronated and normal feet. Methods: This cross-sectional study included 30 participants (15 each in the pronated foot and control groups) are recruited in this study. The foot posture index was used to distinguish between the pronated foot and control groups. The Zebris FDM (Zebris Medical GmbH) stance analysis system was used to measure the FPD on the dominant side during a SLS, which was divided into three phases. A two-way mixed-model ANOVA was used to identify significant differences in FPD between and within the two groups. Results: In the hallux, the results of the two-way mixed-model ANOVAs revealed a significant difference between the group and across different phases (p < 0.05). The hallux, and central forefoot were significantly different between the group (p < 0.05). Moreover, significant differences across different phases were observed in the hallux, medial forefoot, central forefoot, lateral forefoot, and rearfoot (p < 0.05). The post hoc t-tests were conducted for the hallux and forefoot central regions. In participants with pronated foot, the mean pressure was significantly greater in hallux and significantly lower, in the central forefoot during the descent and holding phases. Conclusion: SLSs are widely used as screening tests and exercises. These findings suggest that individuals with pronated feet should be cautious to avoid excessive pressure on the hallux during the descent-to-hold phase of a SLS.

• Journal of Korean Academy of Nursing
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• v.17 no.1
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• pp.24-32
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• 1987

This study was designed to investigate the changes of nurses' role model, perceptions toward occupation, and self actualization value in terms of the phases of socialization process. Two hundred and sixty nine nurses working in clinical settings were randomly selected from 15 general hospitals despersed over Seoul and Kyungki province. Data were gathered by the standardized Perceptual Orientation Test, the Self-actualization Test, and Questionnaires on role models and phases of socialization process developed by the investigators from October 1985 to March 1986. The data were analysed by ANOVA and Pearson's Correlation Coefficient. The results were as follows: 1. The average time period required for the shift of phases of socialization process were; phase Ⅰ, role adjustment, took average 10 months of employment: Phase Ⅱ, interpersonal adjustment, 12 months: and Phase Ⅲ, role conflict, 15 months respectively. Conflict resolution, phase Ⅳ, began to take place 18 months of employment; and shifted to phase V, internalization and self-actualization at 25 months of employment. 2. Throughout 5 consecutive phase, the number of immediate superior nurse model was dominantly the highest among the role models. The number of head nurse role model increased at phase Ⅱ, phase Ⅲ, and phase Ⅳ. Respondents with school model in phase I tended to transfer to work model at phase Ⅱ. 3. The perceptions toward occupation were not significantly influenced by the Phases of socialization process. 4. The score of self-actualization value was not significantly influenced by the phases of socialization process. 5. In regard to perceptions toward occupation, nursing director model group showed significantly lower score in phase I (p<.01). 6. The comparison of self-actualization value between the 5 phases revealed significant difference in phase I: in particular among respondents with school model at p<.05. To conclude: 1. The phase Ⅲ of socialization process is the period of role conflict which occur at 15 months of employment, an6 conflict resolution, phase Ⅳ, begins at 18 months of employment on the average in clinical settings. 2. The immediate superior nurse and the head nurse are important role models for nurses all through their socialization process.