• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.4
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• pp.207-217
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• 2011

In this study the complex formation reactions between uranium(VI) and 2,6-dihydroxybenzoate (DHB) as a model ligand of humic acid were investigated by using UV-Vis spectrophotometry and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The analysis of the spectrophotometric data, i.e., absorbance changes at the characteristic charge-transfer bands of the U(VI)-DHB complex, indicates that both 1:1 and 1:2 (U(VI):DHB) complexes occur as a result of dual equilibria and their distribution varies in a pH-dependent manner. The stepwise stability constants determined (log $K_1$ and log $K_2$) are $12.4{\pm}0.1$ and $11.4{\pm}0.1$. Further, the TRLFS study shows that DHB plays a role as a fluorescence quencher of U(VI) species. The presence of both a dynamic and static quenching process was identified for all U(VI) species examined, i.e., ${UO_2}^{2+}$, $(UO_2)_2{(OH)_2}^{2+}$, and $(UO_2)_3{(OH)_5}^+$. The fluorescence intensity and lifetimes of each species were measured from the time-resolved spectra at various ligand concentrations, and then analyzed based on Stern-Volmer equations. The static quenching constants (log $K_s$) obtained are $4.2{\pm}0.1$, $4.3{\pm}0.1$, and $4.34{\pm}0.08$ for ${UO_2}^{2+}$, $(UO_2)_2{(OH)_2}^{2+}$, and $(UO_2)_3{(OH)_5}^+$, respectively. The results of Stern-Volmer analysis suggest that both mono- and bi-dentate U(VI)-DHB complexes serve as groundstate complexes inducing static quenching.

• The korean journal of orthodontics
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• v.36 no.2 s.115
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• pp.161-169
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• 2006

The purpose of this study was to investigate cephalometrically the short term static velopharyngeal changes in 25 patients (10 boys and 15 girls, aged from 5 years 9 months to 12 years 10 months in the beginning of treatment) with skeletal Class III malocclusions who underwent nonsurgical maxillary protraction therapy with a facemask. The linear, angular and ratio measurements were made on lateral cephalograms. Only the change in hard palatal plane angle was negatively correlated with the change in maxillary depth or N-perp to A (p<0.01). The change in velar angle showed a statistically significant increase (p<0.001). This change was influenced more by the soft palatal plane angle than by the hard palatal plane angle (p<0.001). The changes in soft tissue nasopharyngeal depth and hard tissue nasopharyngeal depth showed statistically significant increases (p<0.001). Correlations between the changes in soft tissue (or hard tissue) nasopharyngeal depth and the change in soft palatal plane angle were significant (p<0.05). The increase in hard palate length was statistically significant (p<0.001). The change in hard palate length was negatively correlated with the change in soft tissue nasopharyngeal depth (p<0.05). The change in need ratio S (C) showed a statistically significant increase (p<0.001). But this difference was within the normal range reported by previous studies. These findings indicate that the velopharyngeal competence was maintained even if the anatomical condition of the static velopharyngeal area were changed after maxillary protraction.

• Computers and Concrete
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• v.22 no.3
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• pp.337-353
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• 2018

The present study focuses on examining the structural behaviour of steel-fibre-reinforced concrete (SFRC) beams under high rates of loading largely associated with impact problems. Fibres are added to the concrete mix to enhance ductility and energy absorption, which is important for impact-resistant design. A simple, yet practical non-linear finite-element analysis (NLFEA) model was used in the present study. Experimental static and impact tests were also carried out on beams spanning 1.3 meter with weights dropped from heights of 1.5 m and 2.5 m, respectively. The numerical model realistically describes the fully-brittle tensile behaviour of plain concrete as well as the contribution of steel fibres to the post-cracking response (the latter was allowed for by conveniently adjusting the constitutive relations for plain concrete, mainly in uniaxial tension). Suitable material relations (describing compression, tension and shear) were selected for SFRC and incorporated into ABAQUS software Brittle Cracking concrete model. A more complex model (i.e., the Damaged Plasticity concrete model in ABAQUS) was also considered and it was found that the seemingly simple (but fundamental) Brittle Cracking model yielded reliable results. Published data obtained from drop-weight experimental tests on RC and SFRC beams indicates that there is an increase in the maximum load recorded (compared to the corresponding static one) and a reduction in the portion of the beam span reacting to the impact load. However, there is considerable scatter and the specimens were often tested to complete destruction and thus yielding post-failure characteristics of little design value and making it difficult to pinpoint the actual load-carrying capacity and identify the associated true ultimate limit state (ULS). To address this, dynamic NLFEA was employed and the impact load applied was reduced gradually and applied in pulses to pinpoint the actual failure point. Different case studies were considered covering impact loading responses at both the material and structural levels as well as comparisons between RC and SFRC specimens. Steel fibres were found to increase the load-carrying capacity and deformability by offering better control over the cracking process concrete undergoes and allowing the impact energy to be absorbed more effectively compared to conventional RC members. This is useful for impact-resistant design of SFRC beams.

• Journal of the Korea Society for Simulation
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• v.25 no.2
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• pp.1-11
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• 2016

The floor field model (hereafter referred to as FFM) is a cellular automata (hereafter referred to as CA)-based walk model used to model pedestrian behavior. Existing studies on FFM conducted experiments with simple structures (that have one room or one obstacle in a room) or relatively complicated structures (that have many rooms). In order to apply the FFM to real buildings, it is necessary to have additional methodologies to process information about the number of rooms, floors, stairs, and exit doors. In particular, it is necessary to process exit doors during this procedure. Exit doors that are recognized by pedestrians are of many types such as exit doors in rooms, stairs connected to corridors, and exit doors in a building. When calculating the static floor field (hereafter referred to as SFF) in the FFM, information about exit doors is needed and simulation results will be different depending on how the SFF is calculated using an exit door among the above-mentioned exit doors. In this study, an XML-format building data model is proposed according to data structures required by the FFM. This study also defines a methodology to process a number of exit doors. Accordingly, this study developed a building data construction and evacuation simulator and simulation experiments were conducted with university campus building.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.33-40
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• 2020

Various studies have been conducted on the structural health monitoring using optical fiber. Optical fibers can be used to measure multiple and distributed strain. Among the optical fiber sensors, FBG sensor has advantages of dynamic response measurement and high precision, but the number of measurement points is limited. Distributed fiber sensors, represented by distributed Brillouin sensors, usually have more than 1000 measurement points, but the low sampling rate makes dynamic measurements impossible. In this study, a hybrid nerve sensor system using only the advantages of the FBG sensor and the distributed Brillouin sensor has been proposed. Laboratory experiments were performed to verify the proposed system, and the accuracy and reproducibility were verified by comparing with commercial sensors. Applying the proposed system, dynamic response ambient measurements are used to evaluate the global state of the structure. When an abnormal condition is detected, the local condition of the structure is evaluated by static response measurement using the distributed measurement system. The proposed system can be used for efficient structural health monitoring.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.23-30
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• 2003

In this study, the various load cases by specified by the IEC61400-1 international specification and GL Regulations for the wind energy conversion system were considered, and a specific composite structure configuration which can effectively endure various loads was proposed. In order to evaluate the structure, the structural analysis for the composite wind turbine blade was performed using the finite element method(FEM). In the structural design, the acceptable configuration of blade structure was determined through the parametric studies, and the most dominant design parameters were confirmed. In the stress analysis using the FEM, it was confirmed that the blade structure was safe and stable for all the considerd load cases. Moreover the safety of the blade root joint with insert bolts, newly devised in this study, was checked against the design loads and also the fatigue loads. The fatigue life for operating more than 20 years was estimated by using the well-known S-N linear damage rule, the load spectrum and Spera's empirical equations. The full-scale static test was performed under the simulated aerodynamic loads. from the experimental results, it was found that the designed blade had the structural integrity. Furthermore the measured results were agreed with the analytical results such as deflections, strains, the mass and the radial center of gravity. The studied blade was successfully certified by an international institute, GL, of Germany.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.441-451
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• 2020

The study was conducted with the aim of identifying the impact of competition anxiety on dance immersion and performance in high school students majoring in dance. As of 2020, online surveys were conducted on students majoring in dance at high schools in Seoul and the metropolitan area. A total of 222 people's data were processed by applying t-test, one-way variable analysis, correlation and multiple regression analysis through SPS 18.0 for Windows, resulting in the following conclusions. First, male students were more confident in their condition than female students, and students who recognized that their family's economic power was in the middle class were more aware. In addition, it was found that the group perceived that economic power was at the top of the list was higher than the median. Second, cognitive anxiety and self-confidence have been shown to have a static effect on immersion into dance. Third, cognitive anxiety and self-confidence have been shown to have a static effect on the achievement of uselessness. Fourth, immersion in dance appeared to be a powerful parameter related to competition anxiety and achievement of dance. To sum up the above conclusions, competition among high school students majoring in dance has been shown to increase their performance by immersing themselves in dance, but further studies of these psychological variables are expected to have side effects.

• Journal of Families and Better Life
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• v.32 no.4
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• pp.23-39
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• 2014

The purpose of this study is to examine if there is any difference due to the general characteristics of middle school students who are beneficiaries of educational welfare services and a special quality of use about educational welfare services. Additionally, the examination has been performed to understand the relationship that exists between the satisfaction about educational welfare services, and adaptation to school life and self-respect of middle school students who are beneficiaries of educational welfare services. The results of the study showed meaningful higher scores by male students than female students only in the environmental adaptation area among lower areas in school life adaptation due to sex. Due to school year, third-year students showed meaningful high scores in school life adaptation. The satisfaction about programs in each area of educational welfare services of middle school students who are beneficiaries of educational welfare services showed a meaningful static relationship with school life adaptation. The inspection of the relationship between satisfaction about educational welfare services and 5 lower areas of school life adaptation showed statistically meaningful results in the order of adaptation to the teacher, adaptation to the environment and adaptation to the class, which are lower areas. The examination on the relationship between self-respect and adaptation to school life showed that self-respect has a static relationship with all lower areas of school life and overall school life adaptation. However, no meaningful relationship was shown between the satisfaction about educational welfare services and self-respect. Also, it was found that the factors of grade, self-respect, the number of service utilization have an effect on school life adaptation. This study has some limitations. But in this study, which is different from other studies which dealt with students who had used partial areas of educational welfare services, students who were using all 4 areas of educational welfare services were selected as subjects. In addition, this study is significant in that basic data has been offered for establishment of a policy on educational welfare services in middle schools in the future.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.205-215
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• 2008

As static traffic assignment has reached its limitation with ITS policy applications and due to the increase of interest in studies of ITS policies since the late 1980's, dynamic traffic assignment has been considered a tool to overcome such limitations. This study used the Dynameq program, which simulates route choice behavior by macroscopic modeling and dynamic network loading and traffic flow by microscopic modeling in consideration of the feasibility of the analysis of practical traffic policy. The essence of this study is to evaluate the feasibility for analysis in practical transportation policy of using the dynamic traffic assignment technique. The study involves the verification of the values estimated from the dynamic traffic assignment with South Korea's expressway network and dynamic O/D data by comparing results with observed link traffic volumes. This study used dynamic O/D data between each toll booth, which can be accurately obtained from the highway Toll Collection System. Then, as an example of its application, exclusive bus-lane policies were analyzed with the dynamic traffic assignment model while considering hourly variations.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.27 no.4
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• pp.76-86
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• 2014

Objective : This study was performed to find out the differential points of the pattern identification for Acne vulgaris and suggest them to the clinic setting Methods : We searched the papers that suggest patterns identification for Acne vulgaris through China National Knowledge Infrastructure(CNKI), Oriental Medicine Advanced Searching Integrated System(OASIS), Korean Traditional Knowledge Portal(KTKP), Korean Studies Information Service System(KISS). We looked through all the papers, excluded unintended papers, and finally chose some papers that are suitable for inclusion. Then, We extracted all the patterns of Acne vulgaris and chose frequently suggested patterns. Finally we extracted symptoms from selected patterns and arranged them in order of frequency. Results and Conclusions : 1. We found 215 papers and chose 17 papers (Korean : 6, Chinese : 11). 2. We extracted total 67 demonstrations and chose Patterns of Wind-Heat, Damp-Heat, Phlegm and Static blood, Disharmony of the Thoroughfare and Controlling vessels. 3. In Acne vulgaris, the pattern of Wind-Heat tends to have a red papule, sometimes pustule, pain with itching, burning sensation, tidal reddening of the cheeks, white head or black head. The pattern of Damp-Heat tends to have a pustule, node, redness and swelling, pain and greasy skin. The pattern of Phlegm and Static blood has a tendency to be a nodule or cystoma that is hard, dark, painful, long lasting and hard to recover and easy to recur with a scar, pimple, pigmentation. The pattern of Disharmony of the Thoroughfare and Controlling vessels tends to be exacerbated before menstruation, have a small papule that is not easily treated under the chin or around the mouth.