• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.4
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• pp.85-99
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• 2021

Due to the continuous unemployment problem, the number of jobs is gradually decreasing, and entrepreneurship is emerging as an alternative. This is because, despite the government operating various start-up support programs to build a start-up-friendly culture, young entrepreneurs cannot endure the valley of death and disappear. Therefore, through this study, we intend to provide implications by analyzing the impact on Entrepreneurial satisfaction, which is essential for continuously running a business, and life satisfaction, which can act as a social awareness. This study was conducted with 573 non-wage workers who belonged to the founders among the participants of the 'College Graduation Occupational Migration Path Survey(GOMS)' survey provided by the Korea Employment Information Service. In order to analyze the relationship between entrepreneurial competency and job fit, Entrepreneurial satisfaction, and life satisfaction, the analysis was conducted using the SPSS 23.0 program. The main research results are summarized as follows. First, entrepreneurial competency has a positive effect on Entrepreneurial satisfaction and life satisfaction. Second, job fit indicates a moderating role in the relationship between entrepreneurial competency and Entrepreneurial satisfaction. Third, start-up satisfaction appears to have a partial mediating role in the relationship between entrepreneurial competency and life satisfaction. Fourth, as a result of analyzing the difference between groups according to the type of start-up(single/partnership), the group that worked together showed higher Entrepreneurial satisfaction and life satisfaction. The main implications of this study are: First, in order to increase the Entrepreneurial satisfaction and life satisfaction of university graduates who are the subject of the study, it will be necessary to design a program that can diagnose and enhance the entrepreneurial competency of students at the university level. Second, entrepreneurial competency is a basic intrinsic factor that founders must have, and it should act as an important evaluation factor when selecting founders for support programs from start-up support organizations as well as founders. Third, it is necessary to maintain mutual trust by documenting problems (positions, wages, management rights, distribution of profits, etc.) that may occur in joint ventures with objective data. Fourth, it is necessary to establish an environment in which the MZ generation, armed with the challenging spirit and creativity, can continue to take on challenges even if they fail.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.21-28
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• 2021

Purpose Brown fat, or brown adipose tissue (BAT), is involved in non-shivering thermogenesis and creates heat through glucose metabolism. BAT activation occurs stochastically by internal factors such as age, sex, and body mass index (BMI) and external factors such as temperature and environment. In this study, as a retrospective, electronic medical record (EMR) observation study, statistical analysis is conducted to confirm BAT activation and various factors. Materials and Methods From January 2018 to December 2019, EMR of patients who underwent PET/CT scan at the National Cancer Center for two years were collected, a total of 9155 patients were extracted, and 13442 case data including duplicate scan were targeted. After performing a univariable logistic regression analysis to determine whether BAT activation is affected by the environment (outdoor temperature) and the patient's condition (BMI, cancer type, sex, and age), A multivariable regression model that affects BAT activation was finally analyzed by selecting univariable factors with P<0.1. Results BAT activation occurred in 93 cases (0.7%). According to the results of univariable logistic regression analysis, the likelihood of BAT activation was increased in patients under 50 years old (P<0.001), in females (P<0.001), in lower outdoor temperature below 14.5℃ (P<0.001), in lower BMI (P<0.001) and in patients who had a injection before 12:30 PM (P<0.001). It decreased in higher BMI (P<0.001) and in patients diagnosed with lung cancer (P<0.05) In multivariable results, BAT activation was significantly increased in patients under 50 years (P<0.001), in females (P<0.001) and in lower outdoor temperature below 14.5℃ (P<0.001). It was significantly decreased in higher BMI (P<0.05). Conclusion A retrospective study of factors affecting BAT activation in patients who underwent PET/CT scan for 2 years at the National Cancer Center was conducted. The results confirmed that BAT was significantly activated in normal-weight women under 50 years old who underwent PET/CT scan in weather with an outdoor temperature of less than 14.5℃. Based on this result, the patient applied to the factor can be identified in advance, and it is thought that it will help to reduce BAT activation through several studies in the future.

• Korean Journal of Plant Resources
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• v.35 no.1
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• pp.134-167
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• 2022

This study conducted monitoring of flora and vegetation in order to utilize basic data for forest wetland conservation targeting outstanding forest wetlands located in the eastern part of Jeonnam Province. The survey was carried out for a total of 54 times from May 2020 to October 2020, 1-2 times each for each season. The vascular plants of outstanding forest wetland in eastern Jeollanam-do were 93 families, 251 genera, 336 species, 5 subspecies, 47 varieties, 7 forma, and a total of 395 taxa. This was about 8.5% of 4,641 species of vascular plants in Korea Peninsula. A total of 8 taxa and 12 taxa were identified Korea endemic plants and rare plants respectively. A total of 68 taxa and 19 taxa of floristic target plants and invasive alien plants were classified each. the naturalized Index was 4.83% and the urbanized Index was 5.90%. As a result of the analysis by wetland type of the forest wetlands, obligate upland plants were the highest in the forest wetlands in the eastern Jeonnam province (61.4%), with unclassified wetland plants 19.1%, facultative wetland plants 8.2%, and obligate wetland plants 4.6%, facultative upland plants 4.5%, and facultative plants 2.3% were confirmed in the order.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.1-8
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• 2008

The purpose of this study was to evaluate the effect of a new resin monomer, filler size and polishing technique on the surface roughness of composite resin restorations using confocal laser scanning microscopy. By adding new methoxylated Bis-GMA (Bis-M-GMA, 2,2-bis[4-(2-methoxy-3-methacryloyloxy propoxy) phenyl] propane) having low viscosity, the content of TEGDMA might be decreased. Three experimental composite resins were made: EX1 (Bis-M-GMA/TEGDMA = 95/5 wt%, 40 nm nanofillers); EX2 (Bis-M-GMA/TEGDMA = 95/5 wt%, 20 nm nanofillers); EX3 (Bis-GMA/TEGDMA = 70/30 wt%, 40 nm nanofillers). Filtek Z250 was used as a reference. Nine specimens (6 mm in diameter and 2 mm in thickness) for each experimental composite resin and Filtek Z250 were fabricated in a teflon mold and assigned to three groups. In Mylar strip group, specimens were left undisturbed. In Sof-lex group, specimens were ground with #1000 SiC paper and polished with Sof-lex discs. In DiaPolisher group, specimens were ground with #1000 SiC paper and polished with DiaPolisher polishing points. The Ra (Average roughness), Rq (Root mean square roughness), Rv (Valley roughness), Rp (Peak roughness), Rc (2D roughness) and Sc (3D roughness) values were determined using confocal laser scanning microscopy. The data were statistically analyzed by Two-way ANOVA and Tukey multiple comparisons test (p = 0.05). The type of composite resin and polishing technique significantly affected the surface roughness of the composite resin restorations (p < 0.001). EX3 showed the smoothest surface compared to the other composite resins (p < 0.05). Mylar strip resulted in smoother surface than other polishing techniques (p < 0.05). Bis-M-GMA. a new resin monomer having low viscosity, might reduce the amount of diluent, but showed adverse effect on the surface roughness of composite resin restorations.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.538-553
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• 1999

The purpose of this study was to compare the shear bond strength and the anticariogenicity of glass ionomer cement with conventional bonding resin and fluoride releasing resin. After the shear bond strength test, scanning electron microscopic observation was performed for the evaluation of the fracture patterns in each group. Under the polarizing light microscope, artificially induced carious lesions were evaluated and the lesion depths of the samples were measured using image analyzing program(Image-Pro $PLUS^{TM}$, USA). 50 sound maxillary premolars were used for the bond strength test and another 30 for the anticariogenic test. Data collected were analyzed statistically using Oneway-ANOVA and Scheffe test. The results were as follows: 1. Glass ionomer groups(G-III, IV, V) generally showed the lower bond strength values than resin groups(G-I, II). 2. Among the two resin groups, G-I showed the higher bond strength than G-II without statistically significant difference between them(p>.05). 3. Within glass ionomer groups, statistical significance was found between G-III and G-V with the superior bond strength in G-V (p<.05). 4. Under the SEM, adhesive failure was the predominant fracture pattern in G-I and II, whereas cohesive failures were mainly observed in G-III. In G-IV and V, mixed type of pattern where the both fracture patterns coexisted within samples could be seen. 5. In evaluation of the depth of artificially developed carious lesion, glass ionomer group showed shallower depth than resin groups with statistical significance between G-III and G-I, II(p<.05). Among resin groups, fluoride releasing resin(G-II) showed the shallower depth than conventional resin(G-I)(p<.05).

• Economic and Environmental Geology
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• v.53 no.5
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• pp.565-583
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• 2020

In recent years, various social issues related to the natural radioactive elements detected in household goods and building materials are addressed, and should be solved promptly. In Korea, for more than 20 years, the Ministry of Environment has investigated the natural radioactive materials such as heavy metals, uranium, and radon in soil or groundwater. The origins of natural radioactive materials in them may have a close correlation with the geological factors including classification of rocks, petrogenetic origins, and deformation characteristics, but the exact geological correlations are not clarified because of the absence of the government policy preserved in the basement rocks, soils as well as groundwater in fault-related reservoirs. This study aims to perform a research on the correlation between the petrogeneses of the Phanerozoic plutonic rocks and natural radioactive concentrations in rocks (radon, uranium, thorium, potassium etc.) in Korea. Among the Phanerozoic plutonic rocks, alkaline plutonic rocks (syenite, monzonite and monzodiorite and alkali granite) show high U and Th concentrations by high solubilities of U, Th, Zr, REE, and Nb until the most extreme stages of magmatic fractionation (viz. crystal fractionation) due to high magma temperature and high alkalinity tendency. The highly fractionated high-K calalkaline and peraluminous granitic rocks (leucogranite, two-mica granite and leucocratic pegmatite are also U and Th concentrations compared with other less or medium fractionated granitic rocks (diorite, granodiorite and granite). The alkaline plutonic rocks are associated with intracontinental rifting and extensional environment after crustal thickening by collisional and subductional processes. In contrast, the dominant calc-alkaline granitic rocks in Korea are related to the arc environment of the subduction zone. In summary, the trends of the U, Th and K concentration from the Phanerozoic plutonic rocks in Korea are closely linked to the petrogenesis of the rocks in tectonic environment. The preliminary data for gamma-spectrometric mesurments of natural radionuclide contents (²²⁶Ra, ²³²Th and ⁴⁰K) in the Phanerozoic plutonic rocks show high values in the alkaline and highly fractionated granitic rocks.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.6
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• pp.387-393
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• 2001

To use as a fundamental data for the sustainable agriculture, which is nowadays a major trend to keep the productivity and conserve the environment, 487 paddy soil samples were collected from 21 regions of the Gyeongnam Province and analyzed the chemical characteristics and microbial population of the soil. The microbial population densities were bacteria $298{\times}10^5$($4{\sim}3000{\times}10^5$ range), fungi $63{\times}10^3$($2{\sim}441{\times}10^3$ range), actinomycetes $19{\times}10^5$($0.2{\sim}1250{\times}10^5$ range), Bacillus sp. $53{\times}10^4$($4{\sim}890{\times}10^4$ range) and Pseudomonas sp. $198{\times}10^4CFU\;g^{-1}$($4{\sim}1724{\times}10^4CFU\;g^{-1}$ range), respectively. The microbial populations of the soil were in general higher in southern area than in the northern area of the Gyeongnam Province. The average ratio of bacteria/fungi population was 473. As soil clay content increased, the populations of aerobic bacteria, actinomycetes and Pseudomonas sp. were remarkably decreased. The ratio of aerobic bacteria and fungi was 1554 in sandy loam and clay loam 1144, while Bacillus sp./fungi ratio was 11 in clay loam and 10 in loam. On the topographical differences, aerobic bacteria and Bacillus sp./fungi ratio were the higher in coastal plains than any other areas. The microbial population densities from different soil types were generally lower in ill-drained paddy field than those of other paddy field. The content of $P_2O_5$, K, Ca, $NO_3-N$ and EC in soil were positively correlated to the population densities of aerobic bacteria, actinomycetes, fungi, Bacillus sp. and Pseudomonas sp.. The soil organic matter and Mg content were also positively correlated to the population densities of aerobic bacteria, actinomycetes, fungi and Bacillus sp.

• Restorative Dentistry and Endodontics
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• v.36 no.3
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• pp.231-237
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• 2011

Objectives: The purpose of this study was to determine the optimal master apical file size with minimal transportation and optimal efficiency in removing infected dentin. We evaluated the transportation of the canal center and the change in untouched areas after sequential preparation with a #25 to #40 file using 3 different instruments: stainless steel K-type (SS K-file) hand file, ProFile and LightSpeed using microcomputed tomography (MCT). Materials and Methods: Thirty extracted human mandibular molars with separated orifices and apical foramens on mesial canals were used. Teeth were randomly divided into three groups: SS K-file, Profile, LightSpeed and the root canals were instrumented using corresponding instruments from #20 to #40. All teeth were scanned with MCT before and after instrumentation. Cross section images were used to evaluate canal transportation and untouched area at 1-, 2-, 3-, and 5- mm level from the apex. Data were statistically analyzed according to 'repeated nested design' and Mann-Whitney test (p = 0.05). Results: In SS K-file group, canal transportation was significantly increased over #30 instrument. In the ProFile group, canal transportation was significantly increased after preparation with the #40 instrument at the 1- and 2- mm levels. LightSpeed group showed better centering ability than ProFile group after preparation with the #40 instrument at the 1 and 2 mm levels. Conclusions: SS K-file, Profile, and LightSpeed showed differences in the degree of apical transportation depending on the size of the master apical file.

• Journal of The Korean Association For Science Education
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• v.20 no.2
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• pp.221-233
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• 2000

Many investigators have reported difficulties in changing the high school students' misconceptions on mechanics. By one possible solution to this problem, some researchers suggested that the students should be taught mechanics at a younger age to make conceptual changes possible. because as they get older they become less willing to change their ideas. The purpose of this study was to compare the patterns of students' conceptual changes on force by age, to find out whether older students were less ready to change their conceptions than younger students. Individual interviews were carried out with 35 students (average ages 13) in middle school class and 50 students (average ages 17) in high school class near by the middle school. Those students who held the misconcetpion that "motion-implies-force (Impetus conception)" were asked to read a student-centered refutational text (anomalous data). In the immediate and delayed posttest, the types of responses of the students were analyzed to find out the patterns of student's conceptual changes on force by age. In result, first, most of students had impetus conception. Some of the students aged 13 understood the force as terminologies related with everyday experiences, while the students aged 17 understood the force as scientific terminologies. Second, there was no evidence to suggest that conceptual change is more difficult for the students aged 17 than aged 13. Third, the students aged 13 showed diverse responses (plain acceptance, critical acceptance, plain rejection, critical rejection) to the refutational text, while the students aged 17 showed restricted responses (critical acceptance, critical rejection). A month later those students who showed the plain acceptance retrogressed unscientific conceptions, while those students who showed critical acceptance maintained scientific conceptions. We did not find out any evidence to suggest that conceptual change is more difficult for older students. These results need deeper investigation on the nature of the loss of plasticity in comparison with other important variables.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.423-433
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• 2019

In order to predict the seabed topography change due to the construction of offshore wind power structures in the west-southern sea of Korea, field observations for tides, tidal currents, suspended sediment concentrations and seabed sediments were carried out at the same time. These data could be used for numerical simulation. In numerical experiments, the empirical constants for the suspended sediment flux were determined by the trial and error method. When a concentration distribution factor was 0.1 and a proportional constant was 0.05 in the suspended sediment equilibrium concentration formulae, the calculated suspended sediment concentrations were reasonably similar with the observed ones. Also, it was appropriate for the open boundary conditions of the suspended sediment when the south-east boundary corner was 11.0 times, the south-west was 0.5 times, the westnorth 1.0 times, the north-west was 1.0 times and the north-east was 1.0 times, respectively, using the time series of the observed suspended sediment concentrations. In this case, the depth change was smooth and not intermittent around the open boundaries. From these calibrations, the annual water depth change before and after construction of the offshore wind power structures was shown under 1 cm. The reason was that the used numerical model for the large scale grid could not reproduce a local scour phenomenon and they showed almost no significant velocity change over ± 2 cm/s because the jacket structures with small size diameter, about 1 m, were a water-permeable. Therefore, it was natural that there was a slight change on seabed topography in the study area.