• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.861-867
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• 2019

$Li_4Ti_5O_{12}$ is a promising next-generation anode material for lithium-ion batteries due to excellent cycle life, low irreversible capacity, and little volume expansion during charge-discharge process. However, it has poor charge capacity at high current density due to its low electrical conductivity. To improve this weakness, porous $Li_4Ti_5O_{12}$ was synthesized by sol-gel method with P123 as chelating agent. The physical characteristics of as-prepared sample was investigated by XRD, SEM, and BET analysis, and electrochemical properties were characterized by cycle performance test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). $Li_4Ti_5O_{12}$ synthesized by 0.01mol ratio of P123/Ti showed most unified particle size, high specific surface area, and relatively high porosity. EIS analysis showed that depressed semicircle size was remarkably reduced, which suggested resistance value in electrode was decreased. Capacity in rate performance showed 178 mAh/g at 0.2C, 170 mAh/g at 0.5C, 110 mA/h at 5C, and 90 mAh/g at 10C. Capacity retention also showed 99% after rate performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1831-1843
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• 2001

In this study, convective boiling tests were conducted for enhanced tube bundles. The surface geometry consists of pores and connecting gaps. Tubes with three different pore sizes (d$_{p}$ = 0.20, 0.23 and 0.27 mm) were tested using R-123 and R-l34a for the following range: 8 kg/m$^2$s G 26 kg/m$^2$s, 10 kW/m$^2$ q0 40 kW/m$^2$and 0.1 $\chi$ 0.9. The convective boiling heat transfer coefficients were strongly dependent on heat flux with negligible dependency on mass flux or quality. For the present enhanced geometry (pores and gaps), the convective effect was apparent. The gaps of the present tubes may have served routes for the passage of two-phase mixtures, and enhanced the boiling heat transfer. The convective effect was more pronounced at a higher saturation temperature. More bubbles will be generated at a higher saturation temperature, which will lead to enhanced convective contribution. The pore size where the maximum heat transfer coefficient was obtained was larger for R-l34a (d$_{p}$ = 0.27 mm) compared with that for R-123 (d$_{p}$ = 0.23 mm). This trend was consistent with the previous pool boiling results. For the enhanced tube bundles, the convective effect was more pronounced for R-134a than for R-123. This trend was reversed for the smooth tube bundle. Possible reasoning is provided based on the bubble behavior on the tube wall. Both the modified Chen and the asymptotic model predicted the present data reasonably well. The RMSEs were 14.3% for the modified Chen model and 12.7% for the asymptotic model.model.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.123-128
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• 1989

An experiment was conducted to study the effect of frequency of defoliation on the ensiling characteristics and nutritive value of Guineaecotype 'A' (Panicum maximum Jacq) grass. Guinea grass harvested at 2, 3, 4, 5, 6, 7, 8, 9, 10 and 12-week cutting intervals was chopped (2 cm) and ensiled alone or with the addition of coconut (Cocos nucifera L.) meal (w/w-fresh weight basis), for periods of 6, 7 or 8 weeks in 2-litre laboratory silos. Dry matter, water soluble carbohydrates, lactic acid, pH, ash, nitrogen and digestibility in vitro were measured in representative samples of preensiled and ensiled material. Dry matter content of silages prepared from herbage harvested at 2 and 3 weeks intervals was lower (P<0.05) compared to longer defoliation intervals. The pH of silage prepared from herbage over 8 weeks old were higher (P<0.05) than those harvested below 8 weeks. The water soluble carbohydrate content of silage prepared from 3-weekly defoliated herbage was higher (P<0.05) than those prepared from longer periods. Lengthened growth period decreased (P<0.001) the crude protein content of the ensiled material, whereas the addition of coconut meal resulted in marginal increases. In vitro organic matter digestibility of the silages decreased (P<0.05) with the increase in forage maturity.

• Journal of Pharmaceutical Investigation
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• v.40 no.6
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• pp.363-366
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• 2010

Identification of compounds that function as P-glycoprotein (P-gp) substrates or inhibitors can facilitate the selection and optimization of new drug candidates. The purpose of this study is to optimize the experimental conditions for in vitro P-gp assay using LLC-GA5 cells, which is a well-known transformant cell line derived by transfecting LLC-PK1 with human MDR1. The amount of rhodamine123 transported by the LLC-GA5 and LLC-PK1 cells was evaluated under the following experimental conditions: 3 different types of transport media, colchicine pretreatment or nontreatment of the cells in the culture media, and with and without poly-L-lysine coating of the culture plates. The assay sensitivity was found to considerably differ depending on the diluents used in the transport media. P-gp-mediated transport in LLC-GA5 cells was most clearly characterized in the Hanks' balanced salt solution based transport media. The sensitivity of P-gp-mediated transport was not changed by colchicine pretreatment or poly-L-lysine coating of the culture plates.

• Journal of the Korean Society of School Health
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• v.34 no.2
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• pp.123-132
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• 2021

Purpose: Adolescents are vulnerable to depression; however, many health policies for adolescents tend to target students in schools. This study aims to identify factors related to depression according to gender among adolescents who have ceased attending school either temporarily or permanently. Methods: The data were generated from the 5th Dropout Youth Panel Survey (2017), and this study included 318 students in the survey that had dropped out of school. The data were analyzed using hierarchical multiple linear regression to identify related factors in depression among the participants. The analyses were performed by SPSS 25.0 program. Results: The depression scores of the students who had ceased attending school were: 20.28±5.47 for boys; 21.23±5.88 for girls. Their depression scores are significantly associated with self-esteem (p<.001 for boys; p=.001 for girls) and social stigma (p=.002 for boys; p=.002 for girls). Among those, peer attachment (p=.050), community integration (p=.004), and community disorder (p<.001) were significantly associated with depression only in boys. Conclusion: The findings of this study suggest that strategies for managing depression in adolescents who have dropped out of school should address the differences in contributing factors according to gender. This study also suggests a basis for approaching such a strategy.

• Progress in Superconductivity
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• v.14 no.1
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• pp.39-44
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• 2012

The fabrications condition and superconducting properties of top-seeded melt growth (TSMG) processed $GdBa_2Cu_3O_{7-y}$ (Gd123) bulk superconductors were studied. Processing parameters (a maximum temperature ($T_{max}$), a temperature for crystal growth ($T_G$) and a cooling rate ($R_G$) through a peritectic temperature ($T_P$) for the fabrication of single grain Gd123 superconductors were optimized. The magnetic levitation forces, trapped magnetic fields, superconducting transition temperature ($T_c$) and critical current density ($J_c$) of the Gd123 bulks superconductors were estimated. Single grain Gd123 bulk superconductors were successfully fabricated at the optimized processing condition. The $T_c$ of a TSMG processed Gd123 sample was 92.5 K and the $J_c$ at 77 K and 0 T was approximately $50kA/cm^2$. The trapped magnetic field contour and magnetic levitation forces were dependent on the top surface morphology of TSMG processed Gd123 samples. The single grain Gd123 samples, field-cooled at 77 K using a Nd-B-Fe permanent magnet with 5.27 kG and 30 mm dia., showed the trapped magnetic field contour of a single grain with a maximum of 4 kG at the sample center. The maximum magnetic levitation forces of the single grain Gd123 sample, field-cooled or zero field-cooled, were 40 N and 107 N, respectively.

• Korean Journal of Mathematics
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• v.7 no.1
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• pp.123-130
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• 1999

We characterize the compactness, weak precompactness and weak compactness in $L^P({\mu},X)$ and in more general space $P^c({\mu},X)$. Moreover, we present this characterization in terms of extremal structure in X.

• East Asian mathematical journal
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• v.21 no.1
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• pp.123-135
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• 2005

We have extended the $H^p$ space and estabilished the derivative of inner functions, Blaschke product on weighted Hardy spaces for the unit disc in complex plane.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.123-126
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• 1993

Hand dibbling in rows produced higher (p < 0.05) fresh and dry matter (DM), fodder yield, higher plant density and cob yield than broadcasted. However, the varying seed rates (40, 50 and 55 kg/ha) did not affect (p < 0.05) the fresh and DM yield and cob yield except for 30 kg/ha seed rate which produced the lowest (p < 0.01). However, the overall average fresh fodder yield and the fresh and DM yield of cob were 24.97, 10.04 and 6.90 t/ha respectively. The overall average plant height (cm), cob/plant (nos.) plant/ha, (nos.) cob/ha (nos.) and weight (g) of one cob were 178, 1.11, 664141, 70104 and 145 respectively for both the sowing methods and the four seed rates. Crude protein contents of maize plant and cob by-products (8.12% and 7.34% respectively) indicated promising cattle feeds along with human food.

• Journal of Korean Biological Nursing Science
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• v.19 no.3
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• pp.123-130
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• 2017

Purpose: This study aimed to identify factors influencing intra-operative core body temperature (CBT), and to develop a predictive model for intra-operative CBT in laparoscopic abdominal surgery. Methods: The prospective observational study involved 161 subjects, whose age, weight, and height were collected. The basal pre-operative CBT, pre-operative blood pressure, and heartbeat were measured. CBT was measured 1 hour and 2 hours after pneumoperitoneum. Results: Explanatory factors of intra-operative hypothermia (< $36^{\circ}C$) were weight (${\beta}=.361$, p< .001) and pre-operative CBT (${\beta}=.280$, p= .001) 1 hour after pneumoperitoneum (Adjusted $R^2=.198$, F= 7.56, p< .001). Weight was (${\beta}=.423$, p< .001) and pre-operative CBT was (${\beta}=.206$, p= .011) 2 hours after pneumoperitoneum (Adjusted $R^2=.177$, F= 5.93, p< .001). The researchers developed a predictive model for intra-operative CBT ($^{\circ}C$) by observing intra-operative CBT, body weight, and pre-operative CBT. The predictive model revealed that intra-operative CBT was positively correlated with body weight and pre-operative CBT. Conclusion: Influence of weight on intra-operative hypothermia increased over time from 1 hour to 2 hours after pneumoperitoneum, whereas influence of pre-operative CBT on intraoperative hypothermia decreased over time from 1 hour to 2 hours after pneumoperitoneum. The research recommends pre-warming for laparoscopic surgical patients to guard against intra-operative hypothermia.