• Journal of the Korean Ceramic Society
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• v.26 no.2
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• pp.201-209
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• 1989

Fine Si-Al-OH coprecipitate powders were prepared from Si- and Al-alkoxides by the hydrolysis method. $\beta$-Sialon powder was obtained from prepared Si-Al-OH coprecipitate by the simultaneous reduction and nitridation method. The syntehsized Sialon powder was pressureless sintered at 175$0^{\circ}C$ for 90 min in N2 atmosphere. The characterization of the Sialon powder was performed with XRD, BET, SEM, TEM and particle size analysis. The sinterability and mechanical properties of sintered bodies were investigated in terms of relative density, M.O.R., fracture toughness, hardness and the morphology of microstructure. The highest values of their mechanical properties were obtained for the $\beta$-Sialon ceramics at Z=1 and those values are as follows : M.O.R., KIC and HV of $\beta$-Sialon ceramics(Z=1) are 499.1 MPa, 5.9MN/m3/2 and 18.7GPa, respectively.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.245-256
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• 1989

Translational movement along an arch wire requires sufficient force to overcome frictional forces between bracket and arch wire. The orthodontist must appreciate the importance of friction in this process, and study out the influencing factors on the level of friction. The purpose of this study was to evaluate the effect of artificial saliva on frictional resistances generated between the bracket and arch wire. Independent variables of this study were arch wire material, angulation and environment. Static frictional forces of cobalt-chromium, heat-treated cobalt-chromium, beta-titanium, stainless steel wires were measured under non-angulated dry, angulated dry, non-angulated saliva, angulated saliva conditions. The results were as follows: 1. Stainless steel wires showed lower friction values in non-angulated dry condition, and heat-treated cobalt-chromium wires showed higher friction values in angulated dry condition. Higher friction values were showed in order of cobalt-chromium. stainless steel, heat-treated cobalt-chromium and beta-titanium wires in non-angulated saliva condition. and were showed in order of stainless steel, cobalt-chromium, heat-treated cobalt-chromium, beta-titanium wires in angulated saliva condition. 2. Angulation increased friction for stainless steel wires under dry condition. 3. Artificial saliva decreased friction for cobalt-chromium wires and increased friction for stainless steel wires under non-angulated condition. 4. Artificial saliva decreased friction for all wires except beta-titanium wires under angulated condition. 5. Regardless of angulation or environment. heat-treated cobalt-chromium and beta-titanium wires showed higher friction values, and stainless steel wires showed lower friction values.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.188-201
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• 1996

One of the initial events required for periodontal regeneration is the attachment, spreading and proliferation of fibroblasts at the healing sites. These have been reported that minocycline stimulates the attachment of gingival fibroblasts and periodontal ligament cells and $TGF-{\beta}1$ enhances the proliferation of periodontal ligament cells. The purpose of this study was to evaluate and confirm the effect of minocycline and $TGF-{\beta}1$ on human gingival fibroblasts and periodontal ligament cells. That gingival fibroblasts and periodontal ligament cells used in this study were obtained from the explants of healthy periodontal ligaments and gingival tissues of extracted 3rd molars or premolar teeth extracted from the patients with orthodontic treatment. The cells were cultured in ${\alpha}-MEM$(minimal essential medium) supplemented with antibiotics and FBS(fetal bovine serum) at $37^{\circ}C$ in a humidified atmosphere of 5% carbon dioxide-95% air. Cells were used between the 5th to 8th passage in this study. The attachment and activity of both cells were evaluated by MTT assay. The results were as follows: 1. Maximum gingival fibroblast attachment was seen at a $50{\mu}g/ml$ dose of minocycline, while maximum periodontal ligament cell attachment was seen at a $100{\mu}g/ml$, and exposure of both cells to minocycline above maximal attachment dose results in a decline from maximum attachment. 2. The activity values of both cells tested minocycline were below to the control activity values at all concentrations. 3. The attachment values of both cells tested $TGF-{\beta}1$ were below or similar to control attachment values. On the above the findings, minocycline stimulated the cell attachment of gingival fibroblasts and periodontal ligament cells and $TGF-{\beta}1$ enhances the cell activity of periodontal ligament cells.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.447-455
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• 2018

This study examined the effects of work values and the career decision level on the major commitment of the university students majoring in social welfare. For this purpose, a survey of 351 undergraduate students majoring in social welfare at 4 universities located in Kangwon-do was conducted and the data were analyzed. The work values consisted of intrinsic values and extrinsic values. The career decision level was measured by the career decision scale (CDS) and the major commitment was measured by the flow state scale (FSS). The research findings are as follows. First, the career decision level (3.43) and major commitment (3.58) of the university students majoring in social welfare were slightly higher than the mid-point on the 5 point Likert scale. In addition, the intrinsic work value (4.05) were higher than the extrinsic work value (3.34). Second, the intrinsic work values and career decision level were positively correlated with the major commitment. Third, the extrinsic work value had a negative effect on the major commitment (${\beta}=-.34$, p<.001); however, the intrinsic work value (${\beta}=.31$, p<.001) and career decision level (${\beta}=.18$, p<.001) had a positive effects on the major commitment. This paper also discusses the theoretical and practical implications for university student's work values, career decision level, and major commitment based on the research findings.

• Journal of the Korean Society of Food Culture
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• v.16 no.4
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• pp.316-322
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• 2001

This study was performed to investigate flavor modification effects of ${\beta}-cyclodextrin$ $({\beta}-CD)$ inclusion complex on the flavor of Doenjang (Korean traditional fermented soy paste) with various substitution levels of 10, 20, and 30%. Water and protein contents of the substituted samples showed significantly lower values compared to those of control(p<0.05). Results of DSC(Differential Scanning Calorimetry) showed that significantly higher ${\Delta}H$ values (386.03 and 304.23) in the 20 and 30% substituted samples represented the stabilized internal cell structures(p<0.05). Internal structures observed with the scanning electronic microscope tended to be less rough and organized making even and ordered internal cell structures as the substitution levels were increased. Results of sensory evaluation showed significantly higher savory flavor and significantly lower bitter and astringent flavors with the substituted samples compared to those of control(p<0.05). Results from this study showed the substitutions of ${\beta}-CD$ could possibly modify unfavored flavors of Doenjang while keeping the unique, nutritional and functional properties when ${\beta}-CD$ was used as a flavor modifier.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.306-310
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• 2007

Setoka (Tangor Norin No.8) is a superior tangor cultivar cultivated in a greenhouse on Jeju Island, and its ${\beta}-cryptoxanthi$n content was determined during the ripening season (September 2005 to March 2006). The ${\beta}-cryptoxanthi$n content of the peel of Setoka fruits was higher than that of the flesh. Also, the ${\beta}-cryptoxanthi$n content in both peel and flesh gradually increased through the ripening season from the beginning of pigmentation, and then decreased slightly late in the ripening season. The ${\beta}-cryptoxanthi$n content in the peel of Setoka fruits varied throughout the season with values of 0.02 (Sep), 0.67 (Nov.), 2.27 (Dec.), 2.88 (Jan.), 2.27 (Feb.), and 2.13 mg% (Mar.). The ${\beta}-cryptoxanthi$n content in Setoka fruit flesh increased throughout the ripening season with values of 0.05 (Sep.), 0.22 (Nov.), 0.57 (Dec.), 0.80 (Jan.), and 0.91 mg% (Feb).

• The Korean Journal of Emergency Medical Services
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• v.22 no.2
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• pp.103-117
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• 2018

Purpose: This study was performed to investigate the level of ethical values and its related factors among some paramedic students. Methods: The subjects of this study were 480 paramedic students from five universities located in G-metropolitan city and J province. Data were collected using a self-administered questionnaire and analyzed using t-test, ANOVA, Pearson's correlations, and multiple regression analysis. Results: The mean scores of level of ethical values, academic self-efficacy and self-esteem were $3.70{\pm}0.45$, $3.15{\pm}0.42$ and $3.60{\pm}0.70$, respectively. In the correlation analysis, ethical value level was significantly positively correlated with self-esteem (r=.195, p< .001) and academic self-efficacy (r=.156, p= .001), of domains in academic self-efficacy, self-regulation efficacy (r=.230, p< .001) and confidence (r=.105, p= .022). In multiple regression analysis, self-esteem (${\beta}=.163$, p= .026), task ease preferences (${\beta}=-.350$, p< .001) and confidence (${\beta}=.403$, p< .001) were significantly related to ethical value levels. In addition, subjects willing to participate in the bioethics education showed higher relevance to ethical values than indifferent subjects (${\beta}=2.751$, p= .003). Conclusion: Concrete and systematic education will be needed in order to foster the establishment of ethical values of the paramedic students. Additionally, to fulfill their roles and obligations as emergency medical technicians, in the field, various educational curricula based on simulated cases in the university should be introduced.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.305-307
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• 2016

The purpose of this paper is to determine the optimal values of the gain parameters used in the tracking module for a highly dynamic warship. The algorithm of the tracking module uses the ${\alpha}-{\beta}-{\gamma}$ filter to compute accurate estimates and update the state variables, that is, positions, velocity and acceleration. The filtering coefficients ${\alpha}$, ${\beta}$ and ${\gamma}$ are determined from set values of the damping parameter, ${\xi}$. Optimization is achieved by plotting a range of the damping parameter ${\xi}$ against the corresponding residual error and then selecting the best value of ${\xi}$ with the minimum residual error. Optimal values of the smoothing coefficients are subsequently computed from the selected damping parameter, ${\xi}$.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.383-387
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• 2001

The kinetics and mechanism of the reactions of thiophenyl dimethylacetates (TDA) and trimethylacetates (TTA) with benzylamines in acetonitrile are studied. The reactions are first order in both the amine and the substrate. Relatively large values of ${\beta}X(\betanuc$ = 1.1-1.5; TDA and 1.1-1.5; TTA) and ${\beta}Z({\beta}lg$ = -1.8~-2.0; DTA and -1.3~-1.6; TTA) for benzylamines, significantly large kH/kD values (=1.2-1.5; DTA and 1.2-1.5; TTA) involving deuterated benzylamines, and large ${\rho}XZ$ (=0.82; TDA and 1.05; TTA) values are interpreted to indicate stepwise acyl transfer mechanism, but with the hydrogen bonded four center type transition state for benzylamine. The relatively greater magnitudes of ${\rho}XZ$ and the secondary kinetic isotope effects involving deuterated nucleophiles are in line with the proposed mechanism.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.451-456
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• 1997

120 heads of korean native calves were examined of serum protein by using cellulose acetate electrophoresis. During 20 days since the calves were purchased, serum protein, fibrinogen values and plasma : fibrinogen ratio were examined in the calves with respiratory and diarrheal disease. The result obtained in this investigation were as follows : 1. Among the 120 heads of calves that were purchased from market, 14 heads(22%) of calves were occurred respiratory disease, and 12 heads(20%) of calves are occurred diarrhea. Occurrence of respiratory disease was 14.5(4~20) days in average and diarrhea was 9.6(2-15) days after they had been purchased. 2. Serum protein fraction were analyzed by cellulose acetate electrophoresis. ${\beta}-globulin$, A/G ratio and ${\beta}_2-globulin$ values were decreased in the calves with respiratory disease. Especially, ${\beta}_2-globulin$ were significantly decreased. In calves with diarrhea, there was no change in ${\beta}-globulin$ values. ${\beta}_2-globulin$ values were higher than that of the normal and respiratory diseased calves. 3. ${\alpha}-globulin$ values were increased in both of calves with diarrhea and respiratory disease. This tendency was due to increase ${\alpha}_2-globulin$ values. 4. The $\gamma$-globulin value of calves with diarrhea was the lowest among the 3 groups. 5. The total protein values of normal calves were $7.0{\pm}1.1g/dl$ and that of respiratory and diarrheal diseased calves were $6.9{\pm}0.9g/dl$ and $6.6{\pm}0.8g/dl$, respectively. Total protein value of calves with diarrhea was lower than that of normal and respiratory diseased calves. Globulin value of calves with diarrhea was the lowest among them. The low value of total protein in diarrheal diseased calves was due to decrease globulin values. 6. The fibrinogen values of calves with respiratory disease ($643{\pm}189mg/dl$) were significantly higher than that of normal calves($533{\pm}135mg/dl$) and calves with diarrhea($572{\pm}188mg/dl$). The plasma : fib. ratio of respiratory diseased calves was $12.0{\pm}4.9$, normal calves was $13.8{\pm}3.5$ and diarrheal diseased calves was $12.8{\pm}4.6$. The ratio of the calves with respiratory disease was significantly decreased.