• Nuclear Engineering and Technology
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• v.44 no.6
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• pp.623-638
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• 2012

The volume of fluid (VOF) model of FLUENT and the lattice Boltzmann method (LBM) are used to simulate two-phase flows. Both methods are validated for static and dynamic bubble test cases and then compared to experimental results. The VOF method does not reduce the spurious currents of the static droplet test and does not satisfy the Laplace law for small droplets at the acceptable level, as compared with the LBM. For single bubble flows, simulations are executed for various Eotvos numbers, Morton numbers and Reynolds numbers, and the results of both methods agree well with the experiments in the case of low Eotvos numbers. For high Eotvos numbers, the VOF results deviated from the experiments. For multiple bubbles, the bubble flow characteristics are related by the wake of the leading bubble. The coaxial and oblique coalescence of the bubbles are simulated successfully and the subsequent results are presented. In conclusion, the LBM performs better than the VOF method.

• Journal of The Korean Astronomical Society
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• v.37 no.3
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• pp.119-129
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• 2004

A new method has been developed to solve the star cluster membership problem. It is based on synthetic photometry employing the Black Body concept as stellar radiation simulator. Synthetic color-magnitude diagram is constructed showing the main sequence band and the positions of binary star systems of combinations of various components through different photometric tracks. The method has been applied to the Hyades. The cluster membership problem has been re-appraised for the cluster (both single and binary) stars. For the binary members, the components' spectral types have been derived by the method. The results obtained agree very well with those found in literature, The method is simpler than the others and can be developed to undertake other cases as multiple star systems.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1737-1740
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• 2006

The optimized structures and complexation energies of bis(18-crown-6-ether) analogue (2) of Trgers base (1) with a series of primary alkylbisammonium ions have been calculated by DFT B3LYP/6-31G(d,p) method. The calculated complexation efficiency (-142.84 kcal/mol) of 2 for butane-1,4-diylbisammonium guest is better than twice of the value (-61.40 kcal/mol) for butylammonium ion. The multiple hydrogen-bond abilities for the complexes are described as the function of the length of the alkyl substituents of the bisammonium guests with normal-alkyl chain [$-(CH_2)_{n-}$, n = 4-8]. The longer bisammonium guest shows the stronger hydrogen-bonding characterizations (the distance and the quasi-linear angle of the N-H…O) to the host 2 than the shorter bisammonium ions. These calculated results agree with the experimental data of the complexation of 2 with bisammonium salts ([$NH_3(CH_2)_nNH_3$] $Cl_2$).

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.78-87
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• 2018

This paper describes specular reflectance measurements of dielectric plates in three waveguide frequency bands: D-band (110-170 GHz), G-band (140-220 GHz), and J-band (220-325 GHz). The transmit (Tx) part of the proposed specular reflectance measurement system is stationary, while the receive (Rx) part and the material under test (MUT) holder are concentric-rotating with a 2:1 speed ratio for specular reflectance measurements. In specular reflectance measurements, the first step measures the specular reflection coefficients of an MUT and a metal plate on the MUT holder located at the center of the Tx and Rx parts, and the second step calculates the specular reflectance defined by the specular reflection power (i.e., intensity) of the MUT normalized to that of the metal plate. Multiple reflection effects between the Tx and Rx antennas and the MUT on the measured specular reflectance are minimized by averaging out the multiple specular reflectances measured with changing the separation distance between the two antennas by ${\lambda}/8$ intervals. Measurement results of the perpendicular-polarized specular reflectance of commonly used dielectric plates are verified by comparing those with the analytic results and show that the results measured over the overlapped frequency range of the D-/G-bands and at the boundary frequency of the G-/J-bands agree well with the results for the other band, respectively.

• Childhood Kidney Diseases
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• v.21 no.2
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• pp.142-146
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• 2017

Purpose: To evaluate changes in quality of life (QoL) in patients with neurogenic bladder treated with clean intermittent catheterization (CIC), who changed from a multiple use catheter (MUC) to single use catheter (SUC). Methods: The Modified Intermittent Self-Catheterization Questionnaire (mISC-Q) was used to determine potential changes in patients' QoL as a result of switching from MUC to SUC. The mISC-Q consists of questions within four categories: ease of use, convenience, discreetness, and symptomatic benefit. Answers were graded as Strongly agree (+2), Agree (+1), Not sure (0), Disagree (-1), and Strongly disagree (-2). Overall patient QoL, as well as by sex, disease (presence of augmentation cystoplasty), and catheterization route (via urethra or urinary diversion), were analyzed. Results: Thirty-eight patients (21M:17F; mean age: $21.7{\pm}5.3y$) submitted questionnaires. For ease of use, SUC was significantly better than MUC (score: 0.364, P=0.002) in all patients. Patients with catheterization via the urethra showed significant favor for SUC in ease of use (score: 0.512, P<0.001) and convenience (score: 0.714, P=0.011), but patients with catheterization via the abdominal stoma of urinary diversion gave negative scores in all categories, though no categories were significant. Conclusion: This study suggested that changing from MUC to SUC may lead to improvements in QoL, especially regarding ease of use. This benefit was clearly found in patients with catheterization via urethra rather than abdominal stoma of urinary diversion.

• The Journal of Korean society of community based occupational therapy
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• v.8 no.1
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• pp.1-10
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• 2018

Objective : The purpose of study is to validate the clinical utility and usability of the Korean version of the Life Space Assessment(K-LSA) which is an assessment tool of community mobility of older adults. Methods : Surveys on the clinical utility and usability of the K-LSA are carried out with a total of aoaa60 occupational and physical therapists. The surveys included the multiple choice questions on the clinical utility and open questions on the usability. Responses to multiple questions are post processed by frequency analysis and technical statistics, and responses to the open questions are categorized by common factors in each questions. Results : Average value of clinical utility ranges from 3.6 to 4.0 with positive responses of 'fair (3 point)', 'agree (4 point)' and 'strongly agree (5 point)' being 95~100%. Average value for clinical usability ranges from 3.6 to 4 with positive answers of 'fair (3 point)', 'easy (4 point)' and 'very easy (5 point)' being 88.3~100%. Additionally out of open-type questions of clinical usability, it was pointed out that the concept of 'neighborhood' for the life space level 3 and 4 is unclear. Conclusion : The current study and research outcomes showed that the K-LSA is a validated tool in Korean health care system for the clinical utility and usability in measuring community mobility, and that it is straightforward in practical use. It will help clinicians and therapists promote the social participation of older adults, and set an intervention goal for enhancing community mobility. It will further help clinicians and researchers in education and research for medical intervention and goal-setting.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.73
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• pp.21-42
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• 2017

A BPO is an irrevocable undertaking given by an Obligor Bank acting on behalf of the buyer to a Recipient Bank acting on behalf of the seller to pay on satisfaction of certain specified conditions. There have been a Trade Service Utility(TSU), a Transaction Matching Application(TMA) and ISO 20022 TSMT messages that core electronic technical systems linked to the BPO. As a key usefulness of the BPO, it brings to market an alternative means of satisfying the risk mitigation, financing and information management needs of banks and businesses engaged in trade. That is, corporates can spread the risk among multiple Obligor Banks by requesting multiple BPOs for the same trade transaction not to exceed the value of the initial transaction. Since the BPO replaces the manual document checking process with the electronic matching of data, buyers and sellers will benefit from significantly increased accuracy and objectivity. By using BPO, buyers and sellers can become trusted counterparties by demonstrating reliability and giving sellers the assurance of being paid on time as per the payment terms and conditions agreed. When compared to L/C, the BPO requires submission of data only. This requires a change of practice of those accustomed to dealing with physical documentation. The beneficiary of a BPO is the Recipient Bank which is always the Seller's Bank. In the meantime, banks will need to agree between themselves that the URBPO 750 will be applied, modified or excluded. However, customers of banks will face low transactional costs due to a fully automated process and standardized data formats used in international trade documentation. There is no amendment and cancellation rules in the URBPO 750s, but only have Assignment of Proceeds rules. As a result, the BPO is likely to enable new business opportunities, lower costs, fast transaction process and strengthen key customer relationships.

• Journal of Astronomy and Space Sciences
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• v.27 no.1
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• pp.1-10
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• 2010

The distance distribution in our planetary system has been a controversial matter. Two kinds of important issues on Titius-Bode's relation have been discussed up to now: one is if there is a simple mathematical relation between distances of natural bodies orbiting a central body, and the other is if there is any physical basis for such a relation. We have examined, by applying it to exo-planetary systems, whether Titius-Bode's relation is exclusively applicable to our solar system. We study, with the $X^2$ test, the distribution of period ratios of two planets in multiple planet systems by comparing it with that derived from not only Titius-Bode's relation but also other forms of it. The $X^2$ value between the distribution of the orbital period derived from Titius-Bode's relation and that observed in our Solar system is 12.28 (dof=18) with high probability, i.e., 83.3 %. The value of $X^2$ and probability resulted from Titius-Bode's relation and observed exo-planetary systems are 21.38 (dof=26) and 72.2 %, respectively. Modified forms we adopted seem also to agree with the planetary system as favorably as Titius-Bode's relation does. As a result, one cannot rule out the possibility that the distribution of the ratio of orbiting periods in multiple planet systems is consistent with that derived from Titius-Bode's relation. Having speculated Titius-Bode's relation could be valid in exo-planetary systems, we tentatively conclude it is unlikely that Titius-Bode's relation explains the distance distribution in our planetary system due to chance. Finally, we point out implications of our finding.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.15-22
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• 2015

The purpose of this research is to analyze converged factors affecting compassion competence in clinical nurses. This is a descriptive correlation research to examine converged factors affecting compassion competence of clinical nurses. Research objects are 233 nurses working in three general hospitals located in Chungnam province, and who understand the purposes of this research and agree to participate in this research. To analyze the data, descriptive statistics, t-test, ANOVA, Pearson's Correlation Coefficient, and stepwise multiple regression analysis were used. The variable which has the greatest effect on compassion competence was compassion satisfaction, followed by clinical experience, compassion fatigue, with those 3 variables explaining 34.4% of compassion competence. Therefore it is necessary to develop specific education programs to improve compassion competence of nurses. Since the explaining power of three variables to compassion competence is 34.4%, it is necessary to add more meaningful variables to explain compassion competence of clinical nurses.

• Structural Engineering and Mechanics
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• v.66 no.3
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• pp.343-351
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• 2018

Brazilian disc test is one of the most widely used experiments in the literature of geo-mechanics. In this work, the pre-holed concrete Brazilian disc specimens are numerically modelled by a two-dimensional discrete element approach. The cracks initiations, propagations and coalescences in the numerically simulated Brazilian discs (each containing a single cylindrical hole and or multiple holes) are studied. The pre-holed Brazilian discs are numerically tested under Brazilian test conditions. The single-holed Brazilian discs with different ratios of the diameter of the holes to that of the disc radius are modelled first. The breakage load in the ring type disc specimens containing an internal hole with varying diameters is measured and the crack propagation mechanism around the wall of the ring is investigated. The crack propagation and coalescence mechanisms are also studied for the case of multi-holes' concrete Brazilian discs. The numerical and experimental results show that the breaking mechanism of the pre-holed disc specimens is mainly due to the initiation of the radially induced tensile cracks which are growth from the surface of the central hole. Radially cracks propagated toward the direction of diametrical loading. It has been observed that for the case of disc specimens with multiple holes under diametrical compressive loading, the breaking process of the modelled specimens may occur due to the simultaneous cracks propagation and cracks coalescence phenomena. These results also show that as the hole diameter and the number of the holes increases both the failure stress and the crack initiation stress decreases. The experimental results already exist in the literature are quit agree with the proposed numerical simulation results which validates this simulation procedure.