• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.55-63
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• 1987

The systematic investigation of the retention behaviors of 18 monosubstituted benzenes in reversed-phase liquid chromatography(RPLC) was studied in order to predict the separation possibility of their mixtures and study the contribution of substituent group to the retentions of solutes. The columns and mobile phases employed in this study were $\mu$ -Bondapak $C_{18}$, $\mu$-Bondapak phenyl columns and methanol/water, acetonitrile/water, and THF/water, respectively. The polar substituents such as phenol, aniline, acetophenone and benzonitrile have smaller capacity factor(k') values than benzene, while nonpolar ones such as alkylbenzenes and halobenzenes show larger k' value. The capacity factors of all solutes increased on both C18 bonded and phenyl bonded phases as the organic solvent content of three organic solvent-water mixtures decreased. The absolute differences in capacity factor(${\Delta}k$') between substituent and benzene were graphically shown for the prediction of the separation of the mixture and interpretation of the elution behavior of substituent. In addition, the selectivity of solvent system for the separation of the mixture was investigated in both two columns and three mobile phases.

• The Journal of the Korean bone and joint tumor society
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• v.20 no.2
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• pp.47-53
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• 2014

Purpose: We analyzed the diagnosis and the treatment outcomes of patients with central low grade osteosarcoma. Materials and Methods: We retrospectively reviewed 16 patients with central low grade osteosarcoma were treated at out institution between 1994 and 2011. Results: There were 4 men and 12 women with mean age of 26 years. Eleven patients were correctly diagnosed but 5 patients were misdiagnosed as osteoid osteoma, non ossifying fibroma, aneurysmal bone cyst, desmoplastic fibroma. 15 patients finally received wide margin en bloc excision and one of them treated under neoadjuvant chemotherapy. Final survival status was continuous disease free in 14 and 1 patient died of renal cell cancer. Remaining 1 with multifocal lesions is alive with disease for 7 years only treated radiation therapy on residual tumors. Nine (56%) of 16 tumors showed extra-osseous extension of tumor (56%) and 1 of them showed extra-compartmental tumors. Conclusion: The diagnosis of central low grade osteosarcoma is challenging, however, considering of the clinical suspicion, the typical findings of radiologic and pathologic features, proper diagnosis is needed. This tumor should be treated with wide excision, even after an intralesional excision, to avoid local recurrence or transformation to higher histologic grade.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.121-127
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• 2011

In this study, possible use of indigenous natural loess (Hwangtoh) as a new binding material via geopolymerization process is examined. Hwangtoh pastes with four different mix proportions of varying alkali liquid concentrations (6 M, 8 M) and the constituents of the binder as well as the alkali liquid at a constant liquid-to-binder ratio of 0.55 were prepared. Analysis of the natural loess (Hwangtoh) paste was carried out as follows : 1) Measurement of compressive strength and weight of cubic specimens versus curing time; 2) Analysis by X-ray diffraction (XRD) and scanning electron microscope (SEM) about reaction product; 3) Porosity analysis of hardened Hwangtoh paste. The result showed that it is possible to prepare Hwangtoh paste with 29.1 MPa at the age of 7 day by using alkali solution (made as 1 : 4.5 the mass ratio of liquefied $Na_2SiO_3$ and NaOH solution and applying the curing temperature of $60^{\circ}C$). Compressive strength development with respect to the degree of moisture evaporation from the paste seems to be independent of curing temperature. Therefore, it seems that higher early strength of the paste specimens cured at higher temperature can be attributed to both higher rate of reaction and moisture evaporation.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.371-375
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• 2002

The calcifying odontogenic cyst(COC) showed diverse terminology or classification, clinicopathologic features as well as in its biologic behavior, although it was recognized as a distinct clinicopathologic entity. The epithelial lining of a COC appears to have the ability to induce the formation of dental tissues in the adjacent connective tissue wall, and that other odontogenic tumors may sometimes be associated with it. This case is a COC associated with a complex odontoma involving an impacted left maxillary lateral incisor in a 5-year-old female child. Radiographic examination revealed a well-demarcated radiolucent lesion partially occupied by a radiopaque mass, involving the left lateral incisor crown. The histologic sections showed a cystic cavity lined with ameloblastic epithelium containing ghost cell masses with admixed with complex odontoma components. The presence of mixed radiolucent-radiopaque lesion in children as observed in this case, the possibility of COC must be considered. In this case, there was no recurrence 1 year after enucleation and the space control is ongoing now.

• Management & Information Systems Review
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• v.36 no.3
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• pp.71-87
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• 2017

This study was conducted to examine differences in the relationship between experiential variables and outcome variables of experiential variables. In this regard, this research tries to construct the items based on past researches and to suggest the problems of the items of past researches. The analysis of various aspects of experiential variables and the validation tests of some models are presented to suggest what the optimal model is and the following suggestions can be made. First, respondents may not feel that the three dimensions of sensation, emotion, and cognition are significantly different. Depending on the respondents, there is a possibility that they may not be able to perceive much of the linguistic difference. The results of this study are summarized as follows. From this point of view, this study suggest that it would be suitable to proceed with the thesis with the experience of simplifying the combination of the five experiences in some combination. Second, there is a correlation between experiential variables, and the effect on outcome variables may vary from one variable to another. And, when there are two outcome variables, assuming a model that affects only the first outcome variable among the experience variables, it is the most suitable model in relation to the performance variable of experience.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.786-790
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• 2016

This paper discusses numerically explored orientation effects on the thermal performance of hollow hybrid fin heat sinks (HHFHSs) under natural convection. A HHFHS consists of an array of hollow pin fins concatenated with plate fins and having perforations near the fin bases. Orientation effects on the footprint-based and mass-based thermal performance of the HHFHS were numerically studied for orientation angles ranging from $0^{\circ}$ to $180^{\circ}$. The performance of the HHFHS was compared with that of a pin fin heat sink (PFHS) having similar physical parameters. The results show that the thermal resistance of the HHFHS did not vary considerably from $0^{\circ}$ to $45^{\circ}$. The thermal resistance increased from $45^{\circ}$ to $90^{\circ}$, reached its maximum at $90^{\circ}$, and decreased consistently from $90^{\circ}$ to $180^{\circ}$. Dissimilar behaviors of the thermal resistance of the HHFHS vs. the PFHS resulted mainly from the effect of heat pumping induced by the internal flows of the hollow fins. Despite various orientations, the mass-based thermal resistance of the HHFHS was found to be nearly 30% smaller than that of the PFHS. This result shows the feasibility of the HHFHS for the lightweight thermal management of electronics under natural convection.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.91-98
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• 2010

Large corpus-based concatenating Text-to-Speech (TTS) systems can generate natural synthetic speech without additional signal processing. Because the improvements in the natualness, personality, speaking style, emotions of synthetic speech need the increase of the size of speech DB, it is necessary to prune the redundant speech segments in a large speech segment DB. In this paper, we propose a new method to construct a segmental speech DB for the Korean TTS system based on a clustering algorithm to downsize the segmental speech DB. For the performance test, the synthetic speech was generated using the Korean TTS system which consists of the language processing module, prosody processing module, segment selection module, speech concatenation module, and segmental speech DB. And MOS test was executed with the a set of synthetic speech generated with 4 different segmental speech DBs. We constructed 4 different segmental speech DB by combining CM1(or CM2) tree clustering method and full DB (or reduced DB). Experimental results show that the proposed method can reduce the size of speech DB by 23% and get high MOS in the perception test. Therefore the proposed method can be applied to make a small sized TTS.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.237-243
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• 2012

Human beings were constantly developing and using tools. This implies the history of humans have been creatively maintained and developed. Humans put its utmost efforts to the development of civilization to lead better life at the same time constantly pursuit to the cultural development such as formative characteristics for the satisfaction of aesthetic needs. Gyubang crafts are regarded as extremely feminine and contained emotions of Korea while being classified as a genre of Korean culture & art. Gyubang crafts were created independent & unique formative beauty on the basis of then social, cultural, religious background, in which those sewing kits being called friends of ladies express the emotion of arts contains cultural depth of its appearance of life as well as its spiritual world of happiness, anger, sorrow and pleasure of ladies. And it was aimed to sought the possibilities to start itself in various ways under the assumption capable to be expressed detail & contemporary taste of the sewing kits that lived together with the ladies in their historic life through linking with ornaments arts with convergence and harmony of formative image. As stated, it could be an opportunity to rediscover the formative characteristics, harmony of convergence, elegance, delicacy, aesthetic beauty focused on sewing kits among Gyubang crafts filled with ladies' scant and spiritual hope and to be re-understood the excellence and the aesthetic beauty of traditional culture & arts through personal ornaments.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.645-650
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• 2004

Calcifying odontogenic cyst(COC) is a rare developmental odontogenic cyst, which shows diverse classification and terminology. Cystic epithelial lining of COC is composed of basal cell layer of columnar cells and overlying layer of stellate reticulum. In the epithelium, ghost cells that might induce adjacent mesenchymal tissue to develop dental organ are shown characteristically. In spite of low rate of recurrence, we have to get a histopathological examination so that odontogenic lesions may recur without fully curettage of lining epithelium. 7-year-old male child came pediatric dentistry in wonkwang university dental hospital in order to check the delayed eruption of left maxillary central incisor. Radiographic examination revealed a well-defined radiopaque mass, overlapping impacted left central and lateral incisor crown. Enucleated mass was tooth-like features and also had epithelium lining. Results of histopathologic procedure, we saw the lots of ghost cell and proliferating hard dental tissues. Also we saw the cystic epithelium cells. It revealed diagnosis of the COC associated complex odontoma. For this reason one should consider of COC when patients present odontoma-like lesion with impacted tooth.

• Journal of the Korean Chemical Society
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• v.40 no.6
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• pp.445-452
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• 1996

Catalytic hydrogenation of ketones and aldehydes by RuH(NO)$L_3$ ($L_3$: $PPh_3$, PhP($CH_2CH_2PPh_2$)$_2$(etp)) was investigated to examine the reaction mechanism and the competence of hydridonitrosyl complexes as catalysts for organic synthesis. RuH(NO)$L_3$ showed catalytic activity for the hydrogenation and the activities of catalysts were dependent on the steric and electronic factors. The less the steric demands of the substrates become, the more activity the catalysts show. For the electronic effect, the more the partial positive charge on the carbonyl carbon atom in ketones becomes and the more the double bond character of carbonyl group in aldehydes becomes, the more active the catalysts are. These results reflect the difference of reaction mechanisms of two substrates, ketones and aldehydes. Catalytic activities of RuH(NO)(etp) and RuH(NO)($PPh_3$)$_3$ in the presence of extra $PPh_3$ toward hydrogenation showed the existence of a reaction pathway accompanied with the change of the bonding modes of NO ligand. The roles of excess $PPh_3$ change with increase of the mole ratio of $PPh_3$ to catalysts; prevention of ligand dissociation from comlexes → bases → ligands. The activity of RuH(NO)(etp) was lower than that of RuH(NO)($PPh_3$)$_3$ toward the hydrogenation of the same substrates mainly due to the structural difference. These catalysts showed the selectivity toward olefin hydrogenation over carbonyl groups in the competitive reaction.