• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.71-81
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• 2017

When an integral pressurized water reactor is operated under low power conditions, once-through steam generator group operation strategy is applied. However, group operation strategy will cause nonuniform coolant flow distribution at the core inlet and lower plenum. To help coolant flow mix more uniformly, a flow mixing chamber (FMC) has been designed. In this paper, computational fluid dynamics methods have been used to investigate the coolant distribution by the effect of FMC. Velocity and temperature characteristics under different low power conditions and optimized FMC configuration have been analyzed. The results illustrate that the FMC can help improve the nonuniform coolant temperature distribution at the core inlet effectively; at the same time, the FMC will induce more resistance in the downcomer and lower plenum.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2197-2202
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• 2020

Background: If there is a difference in leg length, the center of gravity shifts unilaterally toward the short leg, causing loss of balance and secondary postural imbalance, trunk muscle tone changes, gait abnormalities and pelvic imbalance. Objectives: To investigate effects of self exercise program on leg length, balance in adults with leg-length discrepancy. Design: Single blind randomized controlled trial. Methods: Twenty-eight participants were selected and divided into resistance exercise, flexibility exercise, and core exercise. Each exercise was performed for 40 minutes, 3 times a week for 6 weeks. Leg length and balance before and after exercise were measured and analyzed. Results: Following the interventions, resistance exercise group showed significant improvement in balance, but leg length difference did not show significant results. Flexibility exercise group showed significant improvement in leg length difference, but balance did not show significant results. Core exercise group showed significant improvement in leg length difference and balance. There was no significant difference in the comparison between the three groups. Conclusion: This study suggests that customized exercise according to the patient's level is beneficial to the patients.

• Journal of Korean Home Economics Education Association
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• v.34 no.2
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• pp.77-93
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• 2022

The purpose of this study was to identify the latent profiles according to the core competencies of middle school students and to examine whether the parent-child relationship predicts the latent profiles based on the core competencies for students defined by the Korean Ministry of Education. To achieve the purpose of the study, a total of 6,065 second-year middle school students were analyzed from the fourth year of the Korean Educational Longitudinal Study (KELS 2013), which was conducted by the Korean Educational Development Institute in 2016. The results of latent profile analysis and multinomial logistic regression are as follows. First, three latent profiles (higher competency group (19.54%), middle competency group (49.03%), and lower competency group (31.43%)) were derived according to the core competencies. For all groups, the highest competency was communication ability, and the lowest was creative ability. Second, the variables of the parent-child relationship (i.e., parental academic support, emotional support, and attachment level) were significant in predicting differences among the core competency latent profiles. In particular, the emotional support of parents was found to have the greatest influence on the core competencies of middle school students. This study identified the influence of the parent-child relationship on the development of core competencies. Further, it showed that a good family relationship is important for the holistic development of adolescents.

• Bioinformatics and Biosystems
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• v.1 no.2
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• pp.115-122
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• 2006

A three-dimensional pharmacophore model was developed based on 24 currently available inhibitors, which were rationally selected from 472 compounds with diverse molecular structure and bioactivity, for generating pharmacophore of uPA (Urokinase Plasminogen Activator) inhibitors. The best hypothesis (Hypo1) comprised of five features, namely, one positive ionizable group, one hydrogen-bond acceptor group and three hydrophobic aromatic groups. The correlation coefficient, root mean square deviation and cost difference were 0.973, 0.695, and 94.291 respectively, suggesting that a highly predictive pharmacophore model was successfully obtained. The application of the model showed great success in predicting the activities of 251 known uPA inhibitors (test set) with a correlation coefficient of 0.837, and there was also none of the outcome hypotheses that had similar cost difference and RMS deviation (RMSD) with that of the initial hypothesis generated by Cat-Scramble validation test with 95% confidence level. Accordingly, our model should be reliable in identifying structurally diverse compounds with desired biological activity.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.728-730
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• 2003

Bond lengths, harmonic vibrational frequencies and dissociation energies of TlAt are calculated at ab initio molecular orbital and density functional theory using effective spin-orbit operator and relativistic effective core potentials. Spin-orbit effects estimated from density functional theory are in good agreement with those from ab initio calculations, implying that density functional theory with effective core potentials can be an efficient and reliable methods for spin-orbit interactions. The estimated $R_e$, $ω_e$ and $D_e$ values are 2.937 ${\AA}$, 120 $cm^{-1}$, 1.96 eV for TlAt. Spin-orbit effects generally cause the bond contraction in Group 13 elements and the bond elongation in the Group 17 elements, and spin-orbit effects on Re of TlAt are almost cancelled out. The spinorbit effects on $D_e$ of TlAt are roughly the sum of spin-orbit effects on $D_e$ of the corresponding element hydrides. Electron correlations and spin-orbit effects are almost additive in the TlAt molecule.

• Macromolecular Research
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• v.17 no.4
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• pp.265-270
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• 2009

Noble thermosensitive nanoparticles, based on a PNIPAAm-co-AA core and a chitosan shell structure, were designed and synthesized for the controlled release of the loaded drug. PNIPAAm nanoparticles containing a carboxylic group on their surface were synthesized using emulsion polymerization. The carboxylic groups were conjugated with the amino group of a low molecular weight, water soluble chitosan. The particle size of the synthesized nanoparticles was decreased from 380 to 25 nm as the temperature of the dispersed medium was increased. Chitosan-conjugated nanoparticles with $2{\sim}5$ wt% MBA, a crosslinking monomer, induced a stable aqueous dispersion at a concentration of 1mg/1mL. The chitosan-conjugated nanoparticles showed thermo sensitive behaviors such as LCST and size shrinkage that were affected by the PNIPAAm core and induced some particle aggregation around LCST, which was not shown in the NIPAAm-co-AA nanoparticles. These chitosan-conjugated nanoparticles are also expected to be more biocompatible than the PNIPAAm core itself through the chitosan shell structures.

• Clinical and Experimental Pediatrics
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• v.55 no.1
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• pp.1-5
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• 2012

The need for evidence-based decision making in immunization programs has increased due to the presence of multiple health priorities, limited human resources, expensive vaccines, and limited funds. Countries should establish a group of national experts to advise their Ministries of Health. So far, many nations have formed their own National Immunization Technical Advisory Groups (NITAGs). In the Republic of Korea, the Korea Expert Committee on Immunization Practices (KECIP), established by law in the early 1990s, has made many important technical recommendations to contribute to the decline in vaccine preventable diseases and currently functions as a NITAG. It includes 13 core members and 2 non-core members, including a chairperson. Core members usually come from affiliated organizations in internal medicine, pediatrics, obstetrics, microbiology, preventive medicine, nursing and a representative from a consumer group, all of whom serve two year terms. Non-core members comprise two government officials belonging to the Korea Centers for Disease Control and Prevention (KCDC) and the Korea Food and Drug Administration. Meetings are held as needed, but at least twice a year, and sub-committees are formed as a resource for gathering, analyzing, and preparing information for the KECIP meetings. Once the sub-committees or the KCDC review the available data, the KECIP members discuss each issue in depth and develop recommendations, usually by a consensus in the meeting. The KECIP publishes national guidelines and immunization schedules that are updated regularly. KECIP's role is essentially consultative and the implementation of their recommendations may depend on the budget or current laws.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2788-2802
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• 2021

Multigroup cross section (MG XS) generation by the UNIST in-house Monte Carlo (MC) code MCS for fast reactor analysis using nodal diffusion codes is reported. The feasibility of the approach is quantified for two sodium fast reactors (SFRs) specified in the OECD/NEA SFR benchmark: a 1000 MW_th metal-fueled SFR (MET-1000) and a 3600 MW_th oxide-fueled SFR (MOX-3600). The accuracy of a few-group XSs generated by MCS is verified using another MC code, Serpent 2. The neutronic steady-state whole-core problem is analyzed using MCS/RAST-K with a 24-group XS set. Various core parameters of interest (core k_eff, power profiles, and reactivity feedback coefficients) are obtained using both MCS/RAST-K and MCS. A code-to-code comparison indicates excellent agreement between the nodal diffusion solution and stochastic solution; the error in the core k_eff is less than 110 pcm, the root-mean-square error of the power profiles is within 1.0%, and the error of the reactivity feedback coefficients is within three standard deviations. Furthermore, using the super-homogenization-corrected XSs improves the prediction accuracy of the control rod worth and power profiles with all rods in. Therefore, the results demonstrate that employing the MCS MG XSs for the nodal diffusion code is feasible for high-fidelity analyses of fast reactors.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1403-1415
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• 2021

The transient capability of a SP₃ based pin-wise core analysis code SPHINCS is developed and verified through the analyses of the C5G7-TD benchmark. Spatial discretization is done by the fine mesh finite difference method (FDM) within the framework of the coarse mesh finite difference (CMFD) formulation. Pin size fine meshes are used in the radial fine mesh kernels. The time derivatives of the odd moments in the time-dependent SP₃ equations are neglected. The pin homogenized group constants and Super Homogenization (SPH) factors generated from the 2D single assembly calculations at the unrodded and rodded conditions are used in the transient calculations via proper interpolation involving the approximate flux weighting method for the cases that involve control rod movement. The simplifications and approximations introduced in SPHINCS are assessed and verified by solving all the problems of C5G7-TD and then by comparing with the results of the direct whole core calculation code nTRACER. It is demonstrated that SPHINCS yields accurate solutions in the transient behaviors of core power and reactivity.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2107-2110
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• 2009