• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.574-581
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• 2008

Two experiments, involving a total of 100 crossbred pigs (Hampshire$\times$Landrace$\times$Duroc) aged 5 weeks, were used to evaluate the effect of Roselle (Hibicus sabdariffa Linn.) calyx as an antioxidant and acidifier on growth performance. Experiment 1: growth performance response of pigs fed basal corn-soy diet was compared with that of pigs consuming diets that contained 4, 8 and 12% Roselle in powder form, 4 g/kg acidifier (Fra$^{(R)}$Acid Dry) or 100 mg/kg antibiotic (Aurofac$^{(R)}$). All diets were isocaloric and isonitrogenous. Twenty-four castrated male and twelve female pigs were randomly allocated into 6 treatments which comprised 3 replicates (2 male and 1 female) of 2 pigs each. The results demonstrated no beneficial weight gain and feed intake response among treatments at 7, 9 and 11 weeks of age (p>0.05). However, feed-to-gain ratios (FCR) of Roselle-fed groups were significantly different from the basal-diet group at 7 weeks of age (p<0.05). Pigs fed with 8% Roselle had the lowest FCR. Therefore, 8% was set as an appropriate level of Roselle in feed. Experiment 2 was conducted to determine antioxidant and acidifier properties. Pigs were fed similar diets to Experiment 1 except that Roselle was fed to only one treatment at the level of 8%. Sixty-four piglets, 32 castrated male and female each were randomly allocated into 4 treatments which comprised 4 replicates (2 male and 2 female) of 4 pigs each. Body weight was measured. At 7 and 9 weeks of age, four pigs from each treatment were randomly selected. The pH in their gastrointestinal tract, pepsin activity in stomach mucosa, trypsin activity in the pancreas and protein and fat digestibility in the ileum were measured to investigate acidifier properties. For antioxidant properties, malondialdehyde (MDA) and glutathione concentration in plasma and liver were used as parameters. The results showed no significant difference in weight gain, pH or pepsin activity among all treatments at both ages (p>0.05). Nevertheless, trypsin activity and fat digestibility of the Roselle-fed group were higher than the basal-diet group at 7 weeks of age (p<0.05). Glutathione in plasma was significantly different between antibiotic-fed and basal-diet groups (p<0.05). Significant differences were found only in some parameters and between the basal-diet group and the other groups. Therefore, it cannot be precisely concluded that Roselle in powder form has clear acidifier and antioxidant properties in postweaning pigs. Further studies should be undertaken to clearly confirm both properties.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.143-154
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• 2018

This study was performed in order to suggest useful data for color planning of eco-friendly and sensible fashion products. Silk fabrics were dyed in combination with natural indigo and Japanese pagoda tree and were treated with four kinds of mordants after combination dyeing. Then, their colorimetric properties were evaluated. From these composite-dyed silk fabrics, color sensibilities and color preferences of green yellow (GY) color were evaluated among the female university students, and thus, the influences of colorimetric properties and color sensibilities on color preferences were analyzed. When the silk fabrics were dyed in the combination of natural indigo and Japanese pagoda tree and were treated without mordants, they turned green color when indigo 10 g/L was used, and blue-green when indigo 20 g/L was added. And when they were dyed in combination of natural indigo and Japanese pagoda tree and were treated with four kind of mordants after combination dyeing, they turned GY color in almost all cases. The color sensibilities of the GY silk fabrics with the combination dyeing of indigo and Japanese pagoda tree, were classified into three factors: pleasantness, gracefulness, and comfort. Color sensibility factors showed significant differences according to the concentration of indigo and the kinds of mordants. There were almost significant relationships between colorimetric properties and color sensibilities factors of compositely dyed GY silk fabrics. The color preferences of the GY fabrics, which were dyed in the combination of using natural indigo and Japanese pagoda tree and four kinds of mordants, were found to be predicted by the color sensibility in a regression model.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.3
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• pp.168-175
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• 2020

Purpose: The purpose is to test and evaluate the physical properties of commonly used temporary restoration materials and newly emerged materials. Materials and Methods: Four groups of polymer materials were evaluated: Polymethyl methacrylate (PMMA) 2 groups, Polyetheretherketone (PEEK), Polycarbonate. Four physical properties were tested: surface hardness, bending strength, abrasion resistance during wear, wear behavior. The 3-axis bending strength and Vickers hardness test were measured using a universal testing machines respectively. The microstructure was observed with a scanning electron microscope and weight comparison was evaluated after 100,000 chewing tests using a chewing simulator. Kruskal wallis test was performed to evaluate statistical significance. Results: The four groups showed the highest flexural strength and Vickers hardness of PEEK, followed by PC, PMMA-H, PMMA-T. Microstructure observation also showed the least surface roughness in the PEEK group, followed by PC, PMMA-H, PMMA-T. Conclusion: PC is considered to have sufficient mechanical properties that can be applied to the manufacture of temporary teeth. However, further studies, such as biocompatibility, are considered to be necessary for practical clinical applications.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.33-39
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• 2021

BACKGROUND: Globally, large amounts of phosphogypsum (PG), which is a by-product of the phosphate fertilizer production, is deposited in open areas. As PG contains calcium, phosphate, and sulphate, it can be used as a soil amendment in farmlands. This study was conducted to investigate the effects of PG application on properties of field soil and yield and quality of garlic (Allium sativum L.), and to seek appropriate level of PG application into the field. METHODS AND RESULTS: This experiment was conducted by applying PG at four different levels that were adjusted based on 65% calcium base saturation in the field soil: 0% (control), 50% (PG50, 100 kg/10a), 100% (PG100, 200 kg/10a), and 150% (PG150, 300 kg/10a). Following cultivation, soil electrical conductivity (EC), organic matter, available P and exchangeable Ca increased, whilst soil pH decreased. With increase in PG application level, soil EC and exchangeable Ca increased. PG application increased concentrations of water soluble Ca and SO4 across the soil profile, especially in PG150. The highest yield of garlic was found in PG100 treatment. The plant's uptake for N, P, Ca, and S increased by PG applications, but that for K decreased. Moreover, concentrations of S-related amino acids such as cysteine and methionine in garlic increased by PG applications. The increased content of nutrients and amino acids with PG supply might improve yield, quality, and favor of the crop. CONCLUSION: Overall, PG application at 200 kg/10a into a field had the best effect on improving soil fertility as well as yield and quality of garlic. Further studies are required to maximize efficiencies of PG supply in soil management and production of various crops.

• International Journal of Korean Welding Society
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• v.4 no.1
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• pp.46-52
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• 2004

To combine the mechanical advantages of ceramics with those of metals, one often uses both materials within one composite component. But, as known, they have different material properties and fracture behaviors. In this study, a four-point bending test is carried out on $Si_3N_4$ joined to ANSI 304L stainless steel with a Ti-Ag-Cu filler and a Cu interlayer at room temperature to evaluate their longitudinal strain behaviors. And, to detect localized strain, a couple of strain gages are pasted near the joint interfaces of the ceramic and metal sides. The normal strain rates are varied from $3.33{\times}10^5$ to $3.33{\times}10^{-1}s^{-1}$ Within this range, the experimental results showed that the four-point bending strength and the deflection of the interlayer increased with increasing the strain rate.

• Korean Journal of Materials Research
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• v.16 no.3
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• pp.145-150
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• 2006

Various colors of light emitting diodes(LED) and four-band white light sources are obtained using a violet LED and various phosphor films. $BaMg_2Al_{16}O_{27}:Eu\;(blue),\;SrGa_2S_4:Eu\;(green),\;and\;Eu(TTA)_3(PTA)$ (red) phosphors are dispersed in poly-vinyl-alcohol aqueous solutions, and phosphor films are prepared by coating the suspensions to PET film. The narrow band emission of $Eu(TTA)_3(PTA)$ phosphor has excellent red luminescent property for four-band white light excited by the violet LED.

• Honam Mathematical Journal
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• v.41 no.4
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• pp.725-744
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• 2019

In this paper we introduce some new types of double difference sequence spaces defined by a new definition of convergence of double sequences and a double series with the help of sequence of Orlicz functions and a four dimensional bounded regular matrices A = (a_rtkl). We also make an effort to study some topological properties and inclusion relations between these sequence spaces. Finally, we compute the closed ideals in the space 𝑙²_∞.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.45.1-45.1
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• 2014

We present the results of a time series analysis of the long-term radio lightcurves of four blazars: 3C 279, 3C 345, 3C 446, and BL Lacertae. We exploit the data base of the University of Michigan Radio Astronomy Observatory (UMRAO) monitoring program which provides densely sampled lightcurves spanning 32 years in time in three frequency bands located at 4.8, 8, and 14.5,GHz. Our sources show mostly flat or inverted (spectral indices -0.5 < alpha < 0) spectra, in agreement with optically thick emission. All lightcurves show strong variability on all time scales. Analyzing the time lags between the lightcurves from different frequency bands, we find that we can distinguish high-peaking flares and low-peaking flares in accord with the classification of Valtaoja et al. (1992). The periodograms (temporal power spectra) of the observed lightcurves are consistent with random-walk powerlaw noise without any indication of (quasi-)periodic variability. The fact that all four sources studied are in agreement with being random-walk noise emitters at radio wavelengths suggests that such behavior is a general property of blazars.

• Elastomers and Composites
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• v.54 no.1
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• pp.35-39
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• 2019

Four different polymer compounds were prepared from four kinds of plasticizers, viz. di-2-ethylhexyl azelate (DOZ), di-2-ethylhexyl adipate (DOA), di-2-ethylhexyl sebacate (DOS), and di-2-butyl sebacate (DBS), for making cable sheaths for ships. Ethylene-vinyl acetate and ethylene-propylene-diene-copolymer as matrix polymers and ethylene-vinyl acetate grafted maleic anhydride as a coupling agent were compounded with a flame retardant, crosslinking agent, filler, and other additives, besides the plasticizer to obtain the polymer compounds. The polymer containing DOZ showed the highest MH and ${\Delta}T$ in the rheology test, while that containing DBS was found to have the lowest tensile strength and highest elongation because of low ${\Delta}T$. The four polymers showed similar values (31.7-31.9) for flame resistance, while the polymer containing DOZ showed the highest value for cold resistance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.4
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• pp.229-241
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• 2021

Since 2010, polymer-based magnetoelectric (ME) composites have been developed with detailed investigations of multiferroic properties such as piezoelectric, magnetostrictive, and magnetoelectric, etc. In particular, as a piezoelectric polymer, poly(vinylidene fluoride) and its co-polymers have been widely used in ME composites for energy harvesting, health monitoring, environment treatment, and bio-medical applications. In this study, main research trend and selected experimental results of polymer-based ME composites are briefly reviewed with respect to composite structure as well as application field. A conclusion was drawn that the polymer-based ME composites would be feasible as flexible devices or functional membranes in the near future.