• Journal of Mechanical Science and Technology
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• 제17권1호
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• pp.114-121
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• 2003

Water droplet erosion is one of major concerns in the design of modern large fossil steam turbines because it causes serious operational problems such as performance degradation and reduction of service life. A new erosion model has been developed in the present study for the prediction of water droplet erosion of rotor blades operated in wet steam conditions. The major four erosion parameter : impact velocity, impacting droplet flow rate, droplet size and hardness of target are involved in the model so that it can also be used for engineering purpose at the design stage of rotor blades. Comparison of the predicted erosion rate with the measured data obtained from the practical steam turbine operated for more than 90,000 hours shows good agreement.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권2호
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• pp.71-78
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• 2000

The chlorination of municipal drinking water supplies leads to the formation of so-called disinfection by-products(DBPs), many of which have been reported to cause harmful health effects based on animal studies. This study was conducted: 1) to observe seasonal changes in the major DBPs at four sampling sites on a drinking water distribution system located in Chunchon, Kangwon Do; and 2) to examine the effects of major water quality parameters on the formation of DBPs. During the field sampling, the water temperature, pH, and total and free chlorine residuals were all measured. The water samples were then analyzed for total organic carbon(TOC) and eight disinfection by-products in the laboratory. Chloroform, dichloroacetic acid, and trichloroacetic acid were the major constituents of the measured DBPs. The concentrations of the total DBPs were highest in fall, particularly in October, and lowest in summer. The concentrations of the total DBPs increased with increasing TOC concentrations. Multiple regression analyses showed that the concentrations of chloroform, bromodichloromethane, and chloral hydrate were linearly correlated with the pH. Other water parameters were not included in the regression equations. Accordingly, these results suggest that TOC and pH are both important factors in the formation of DBPs.

• 디지털산업정보학회논문지
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• 제15권3호
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• pp.149-173
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• 2019

Software education is inevitable for the success of the Fourth Industrial Revolution, and university education also requires innovation to cope with revolutionary change of the society. The number of students seeking employment in the IT field is steadily increasing regardless of the major of the student. However, the existing software-related courses offered by universities or private educational institutions are limited. This paper analyzes the existing software curriculum of several major universities for non-IT major students. In addition, in-depth surveys by students at Seoul Theological University is conducted to figure out the demand for the advanced level computer science subjects. Finally, new software education curriculum is proposed to fulfill the needs of non-IT major students and to improve the employment rate of non-IT major students seeking tech companies. The new curriculum will help to cultivate intermediate level IT experts that bridge the gap between advanced level IT experts and primitive level computer technicians.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.950-969
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• 2022

This study aimed to determine the effect of dietary supplementation with Acremonium terricola culture (ATC) on the quality, conventional characteristics, and flavor substances of Hortobágy goose meat. A total of 720 one-day-old goslings were divided into four dietary treatments, each consisting of six cages of 30 goslings. The dietary conditions consisted of the control group and three treatment groups supplemented with 3, 5, or 7 g/kg ATC. In male geese, supplementation with 3 g/kg ATC elevated the crude ash (CA) content of the thigh muscle compared to the control group, and the CA content of the pectoralis major was significantly elevated when geese were supplemented with 5 g/kg ATC (p < 0.05). In females, compared with the control group, supplementation with 7 g/kg ATC enhanced the crude protein (CP) content of the pectoralis major. Supplementation with 7 g/kg ATC also increased the crude fat (CF) content of the pectoralis major in females as well as in both sexes; moreover, this supplementation dose increased the inosinic acid content of the thigh muscle in males and in both sexes. In contrast, supplementation with 5 g/kg ATC decreased the pH of the thigh muscle at 12 h postmortem (p < 0.01). No significant changes in meat color, water loss rate, shear force, moisture content or amino acid (AA) levels were observed after ATC supplementation (p > 0.05). Levels of saturated fatty acids (SFAs) and polyunsaturated FAs (PUFAs) in the pectoralis major and levels of SFAs, monounsaturated FAs (MUFAs), and PUFAs in the thigh muscle were not affected by the supplementation. Overall, ATC supplementation had positive effects on the pH, and CA, CP, CF, inosinic acid contents as well as on the FA composition of gosling meat. The optimal level of ATC supplementation was 7 g/kg in goslings from 1 to 70 days of age.

• Asian-Australasian Journal of Animal Sciences
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• 제21권1호
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• pp.124-130
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• 2008

Streptococcus (Strep.) agalactiae is one of the major pathogens of bovine mastitis and is the main cause of subclinical infection. This study attempted to develop a rapid PCR diagnosis procedure using milk samples collected on filter paper disks. Chromatographic filter paper was employed as the preservation media and kept at room temperature for one to four weeks. The revival rate of Strep. agalactiae kept on dried filter paper disks was affected by the pretreatment preservation time. The revival test suggested that not all the bacteria in artificially contaminated milk samples on the filter paper disks could be recovered. After that, a PCR based on the 16-23S intergenic spacer region of Strep agalactiae was performed. The results distinguished the strep. agalactiae from major pathogens of bovine mastitis at a $2{\times}10^2$ colony forming units (CFU)/ml level, which showed similar sensitivity to the results from liquid milk samples. The results also showed that milk samples collected on filter paper disks could be kept at room temperature for one to four weeks with little negative effect on sensitivity and specificity. The field test showed that the diagnostic sensitivity and specificity was 96.15% and 98.60%, respectively. In conclusion, the protocol will provide a rapid and economic procedure for the detection of bovine mastitis.

• 한국간호교육학회지
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• 제29권2호
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• pp.190-198
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• 2023

Purpose: This study was conducted to identify the effect of verbal violence, clinical practice stress, and coping with stress on the major satisfaction in nursing students during clinical practice. Methods: A cross-sectional study was used. A survey was conducted from May 3 to May 10, 2022, on 200 nursing students who were in their junior and seneior years at two universities in Gyeongsangbuk-do. Descriptive statistics, frequency analysis, independent t-test, one-way ANOVA, Scheffé's test, Pearson correlation coefficient, and hierarchical regression analysis were employed to analyze the data. Results: Major satisfaction was found to be significantly negatively correlated with verbal violence (r=-.30, p<.001) and clinical practice stress (r=-.15, p=.032) and to be positively correlated with coping with stress (r=.24, p<.001). Their satisfaction with clinical practice (β=.29, p=.037), verbal violence (β=-.23, p<.001), coping with stress (β=.16, p=.015), religion (β=.14, p=.041), and clinical practice stress (β =-.13, p=.048) explained 19.3% of the variance in nursing students' major satisfaction during clinical practice. Conclusion: A verbal violence and coping with stress program for nursing students should be developed to increase nursing students' major satisfaction during clinical practice.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.942-948
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• 2005

New polymorphism of major histocompatibility complex B-G genes was investigated by amplification and digestion of a 401bp fragment including intron 1 and exon 2 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique with two restriction enzymes of Msp I and Tas I in eight breeds of Chinese indigenous chickens and one exotic breed. In the fragment region of the gene, three novel single nucleotide polymorphisms (SNPs) were detected at the two restriction sites. We found the transition of two nucleotides of A294G and T295C occurred at Tas I restriction site, and consequently led to a non-synonymous substitution of asparagine into serine at position 54 within the deduced amino acid sequence of immunoglobulin variable-region-like domain encoded by the exon 2 of B-G gene. It was observed at rare frequency that a single mutation of A294G occurring at the site, also caused an identical substitution of amino acid, asparagine 54-to-serine, to that we described previously. And the transversion of G319C at Msp I site led to a non-synonymous substitution, glutamine 62-to-histidine. The new alleles and allele frequencies identified by the PCR-RFLP method with the two enzymes were characterized, of which the allele A and B frequencies at Msp I and Tas I loci were given disequilibrium distribution either in the eight Chinese local breeds or in the exotic breed. By comparison, allele A at Msp I locus tended to be dominant, while, the allele B at Tas I locus tended to be dominant in all of the breeds analyzed. In Tibetan chickens, the preliminary association analysis revealed that no significant difference was observed between the different genotypes identified at the Msp I and Tas I loci and the laying performance traits, respectively.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.146.1-146.1
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• 2003

A major protein was isolated from ginseng root (Panax ginseng C.A. Meyer) using a combination of ammonium sulfate fractionation, gel filtration chromatography, ion-exchange FPLC. Electrophoretic and gel permeation chromatographic studies revealed that the major protein, GMP, is composed of two subunits of approximately 28 kDa. In this, investigated the ability of GMP to inhibit the oxidation of low-density lipoprotein (LDL). GMP inhibited $Cu^{2+}$ (5$\mu$M)-promoted oxidation of LDL (125$\mu$g protein/mL) in a dose-dependent mamer (0~5 $\mu$M), with a maximal inhibitor at GMP/copper ratio of 1:10 and an $IC_{50}$ value of 0.2 $\mu$M, as determined by measurement TBARS. (omitted)

• Journal of Ginseng Research
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• 제35권3호
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• pp.375-383
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• 2011

In the previous report, we have demonstrated that ginsenoside Rc, one of major ginsenosides, is a major component for the restoration for normal growth of worms in cholesterol-deprived medium. In the present study, we further investigated the roles of minor ginsenosides, such as ginsenoside $Rh_1$ and $Rh_2$, ginsenoside metabolites such as compound K (CK), protopanaxadiol (PPD), and protopanaxatriol (PPT) and ginsenoside epimers such as 20(R)- and 20(S)-ginsenoside $Rg_3$ in cholesterol-deprived medium. We found that ginsenoside $Rh_1$ almost restored normal growth of worms in cholesterol-deprived medium in F1 generation. However, supplement of ginsenoside $Rh_2$ caused a suppression of worm growths in cholesterol-deprived medium. In addition, CK and PPD also slightly restored normal growth of worms in cholesterol-deprived medium but PPT not. In experiments using ginsenoside epimers, supplement of 20(S)- but not 20(R)-ginsenoside $Rg_3$ in cholesterol-deprived medium also almost restored worm growth. These results indicate that the absence or presence of carbohydrate component at backbone of ginsenoside, the number of carbohydrate attached at carbon-3, and the position of hydroxyl group at carbon-20 of ginsenoside might plays important roles in restoration of worm growth in cholesterol-deprived medium.

• Journal of Ecology and Environment
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• 제34권4호
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• pp.371-379
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• 2011

To determine the peak dispersal times of allergenic pollen grains in Ulsan, Korea, we performed continuous airborne pollen counts at three stations (Sts. A, B, and C) in Ulsan from August 2009 to November 2010. Pollen grains were sampled using a Durham sampler. Two peak pollen dispersal seasons were observed per year. The peak seasons generally coincided with the flowering period of anemophilous trees: Taxodiaceae (February), Alnus (March), Cupressaceae (April), Quercus, and Pinus (May), and with the flowering phase of herbs from August to November, e.g., Humulus, Artemisia, Gramineae, and Ambrosia from August through September. The highest concentration of airborne pollen was from Pinus (68%), followed by Quercus (15%), Alnus (6%), and Humulus (2%); whereas very low pollen concentrations were from Taxodiaceae, Cupressaceae, Artemisia, Gramineae, and Ambrosia (${\leq}$ 1% of the annual total airborne pollen concentration). Our findings indicate that Alnus and Humulus pollen are major allergens whereas those of Pinus and Quercus are minor allergens. The concentration of Alnus pollen grains at St. C was over five times that at Sts. A and B. This finding implies that individuals living at or near St. C are exposed to high concentrations of Alnus pollen before and after March, which is the flowering period of the alder tree. From August to September, individuals living at or near St. B are exposed to high concentrations of Humulus pollen. Our study suggests that Alnus pollen may be the major aeroallergen causing pollinosis in the spring at St. C and Humulus pollen may be the major aeroallergen in autumn at St. B.