• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.221-227
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• 2016

The main shaft is one of the key components connecting the rotor hub and gear box of a wind power generator. Typically, main shafts are manufactured by open die forging method. However, the main shaft for large MW class wind generators is designed to be hollow in order to reduce the weight. Additionally, the main shafts are manufactured by a casting process. This study aims to develop a manufacturing process for hollow main shafts by the open die forging method. The design of a forging process for a solid main shaft and hollow shaft was prepared by an open die forging process design scheme. Finite element analyses were performed to obtain the flow stress by a hot compression test at different temperature and strain rates. The control parameters of each forging process, such as temperature and effective strain, were obtained and compared to predict the suitability of the hollow main shaft forging process. Finally, high productivity reflecting material utilization ratio, internal quality, shape, and dimension was verified by the prototypes manufactured by the proposed forging process for hollow main shafts.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.138-146
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• 1999

Textural properties of the cooked wheat noodles prepared from 5 Korean wheat varieties (Woori, Yeunpa, Allgeuru, Geuru, and Tapdong), and 3 foreign wheat varieties (ASW, WW and DNS) were evaluated by mechanical and sensory analyses, and their correlations to the physicochemical properties of the flours were examined. Cooking loss for noodle was negatively correlated with protein content, and weight increase during cooking showed a positive correlation with damaged starch content. From the mechanical tests, hard wheats (Tapdong and DNS) showed greater values for hardness, chewiness and tensile strength of the noodles than soft wheats. Foreign soft wheats (ASW and WW) showed relatively lower values for these attributes than the Korean soft wheats. Among the mechanical tests, multi-blade compression shear test had better correlations to the sensory characteristics than 10% compression, repeated compression and tensile tests. Among the flour characteristics, protein content was the most determining factor for the textural properties of noodle. Amylose increased the tenderness and slipperiness, but decreased internal firmness of the noodle. The Korean soft wheat noodles showed relatively darker color for the cooked noodle than WW or ASW. From acceptability test for noodle, Geuru was most preferred among the tested wheat varieties.

• Journal of Pharmaceutical Investigation
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• v.35 no.2
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• pp.123-127
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• 2005

An HPLC method was employed for the determination of ethambutol in human plasma. After addition of internal standard (IS, octylamine, $2\;{\mu}g/mL$) and alkalinization of the plasma with 5 M sodium hydroxide, the drug and IS were extracted into the mixture of chloroform and diethyl ether (40:60, v/v). Following a 15-min vortex-mixing and a 10min centrifugation, the organic phase was spiked with $100{\mu}L$ of phenylethylisocyanate $(2000{\mu}g/mL)$ for chemical derivatization, mixed for 5 min and evaporated to dryness under a stream of nitrogen. The residue was reconstituted with $100{\mu}L$ of mobile phase and $20{\mu}L$ was injected into C18 column with a mobile phase consisting of methanol:water (70:30, v/v). The samples were detected utilizing an ultraviolet detector at 200 nm. The method was specific and validated with a limit of $0.15\;{\mu}g/mL$. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of this method was demonstrated by analysis of human plasma after oral administration of a single 1200-mg dose to 20 healthy subjects. From the plasma ethambutol concentration vs. time curves, the mean AUC was $9.61{\pm}1.64\;{\mu}g{\cdot}hr/mL$ and Cmax of $2.68\;{\mu}g/mL$ reached 2.73 hr after administration. The mean biological half-life of ethambutol was $3.46{\pm}1.21$ hr. Based on the results, this simple and validated assay could readily be used in any pharmacokinetic studies using humans.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.65-71
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• 2009

The aim of the present study was to evaluate the bioequivalence of two domperidone maleate tablets, Motilium-$M^{(R)}$ Tablet (Janssen Korea Ltd., reference product) and $Toriem^{(R)}$ Tablet (Daewon Pharm. Co., Ltd., test product). Domperidone was extracted by liquid-liquid extraction using tert-butyl methyl ether and separated in less than 3 min on $C_{18}$ reverse-phase column using an isocratic elution. A tandem mass spectrometer, as detector, was used for quantitative analysis in positive mode by a multiple reaction monitoring mode to monitor the m/z $426.1{\rightarrow}119.1$ and the m/z $837.4{\rightarrow}158.2$ transitions for domperidone and the internal standard (roxithromycin), respectively. Calibration curves, from $0.05{\sim}50$ ng/mL of domperidone, showed correlation coefficients (r) higher than 0.9941. Intra day and inter day precision (C.V. %) for quality control were ranged from 10.04 to 16.09% and from 10.87 to 18.69%, respectively. The lower limit of quantification (LLOQ) of domperidone was 0.05 ng/mL. The method described is precise and sensitive and has been successfully applied to the study of bioequivalence of domperidone in 24 healthy Korean volunteers. Twenty-four healthy male Korean volunteers received a single dose of each medicine ($2{\times}12.72\;mg$ domperidone maleate) in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of domperidone were monitored for over a period of 24 hr after the administration. $AUC_{0-t}$ (the area under the plasma concentration-time curve) was calculated by the linear trapezoidal rule. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. The 90% confidence intervals for the log transformed data were within acceptable range of log 0.8 to log 1.25 (e.g., $log\;0.92{\sim}log\;1.05$ for $AUC_{0-t}$, $log\;0.81{\sim}log\;1.05$ for $C_{max}$). The major parameters, $AUC_{0-t}$ and $C_{max}$ met the criteria of KFDA for bioequivalence indicating that $Toriem^{(R)}$ tablet is bioequivalent to Motilium-$M^{(R)}$ tablet.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.535-541
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• 2020

FCAW is used mainly in the welding of carbon steel and alloy steel because it can be welded in all positions and can obtain excellent quality at sites with variable working conditions. Recently, many studies in Korea have estimated the fatigue strength, residual stress, and deformation, and to develop a fillet welding process. On the other hand, there have been few studies of the mechanical properties based on the strength, macro and magnetic particle test results for fillet welding. This study shows the following results through fillet welding, macro testing and strength testing using SM490A (solid-structure rolled steel) for thick plates using SS400 (rolled steel) for the upper plate and FCAW. The hardness test, macro test and magnetic particle test were then conducted. The hardness tests showed that all result values were smaller than the KS B 0893 standard values of 350Hv. The macro-test showed that each type of welded part was in a normal organic state and that there were no internal errors, bubbles, or impurities on the front of the welded part. Therefore, there were no concerns about lamination. The magnetic particle examination showed no problems.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.865-875
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• 2018

Selection of optimum reaction conditions during deoxygenation process of palm oil is essential factor to obtain the maximum yield of bio-jet fuel. In this context, the deoxygenation of palm oil was carried out in a fixed bed reactor with an internal diameter of 1 inch loaded with a 1 wt.% $Pt/Al_2O_3$ catalyst. The composition of the organic liquid product(OLP), which can be utilized as a transportation fuel through the upgrading process, was analyzed by a gas chromatography method. The palm oil/hydrogen ratio and hydrogen pressure in the feed affected the decarboxylation(DCB) and hydrodeoxygenation(HDO) reactions, resulting in a change in the composition of the OLP. As the reaction temperature increased, the continuous cracking reaction of the deoxygenation product was promoted and the product composition in the $C_5{\sim}C_{14}$ region was increased. Thus, the results can help to understand the characteristics of deoxidation reaction of palm oil as well as the subsequent process, hydro-upgrading, to obtain the maximum yield of bio-jet fuel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.249-256
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• 2020

It is expected that the technology of the fourth industrial revolution will increase the productivity and efficiency of the industrial world. Many countries are providing political and financial supports to make big advances in the technology. Especially, developed countries, such as USA, Germany and Japan, are trying to use the technology for manufacturing and finance industry, and to increase the opportunity of test-bed environment. However, many restrictions hinder adopting non-governmental technology in defense due to various limitations such as national security and protection of technology. In this study, we propose methods to adopt new and non-governmental technology in defense through by investigating internal and external policies related to technology and case studies. First, it is necessary to expand opportunities to let small and medium sized companies participate in defense R&D projects. Second, it is important to improve R&D systems for introducing new and non-governmental technology on the defense industry. Third, it is needed to increase test-bed environments for experimenting and evaluating new technologies in the defense industry. Thus, we expect that the proposed methods will help form strategies for small and medium sized companies, and analyze trends for introducing new technologies in the defense industry.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1313-1320
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• 2014

Introduction: Although most prostate cancers initially respond to castration with luteinizing hormonereleasing analogues or bilateral orchiectomy, progression eventually occurs. Based on the exciting results of several randomized controlled trials (RCTs), it seems that patients with metastatic castration-resistant prostate cancer (mCRPC) might benefit more from treatment withabiraterone. Therefore we conducted a systematic review to evaluate the efficacy and toxicity of abiraterone in the treatment of mCRPC. Methods: Literature was searched from Embase, PubMed, Web of Science, and Cochrane Library up to July, 2013. Quality of the study was evaluated according to the Cochrane's risk of bias of randomized controlled trial (RCT) tool, then the Grading of Recommendations Assessment, Development and Evaluation (GRADE) System was used to rate the level of evidence. Stata 12.0 was used for statistical analysis. Summary data from RCTs comparing abiraterone plus prednisone versus placebo plus prednisone for mCRPC were meta-analyzed. Pooled hazard ratios (HRs) for overall survival (OS), radiographic progression-free survival (RPFS) and time to PSA progression (TTPP); Pooled risk ratios (RR) for PSA response rate, objective response rate and adverse event were calculated. Results: Ten trials were included in the systematic review; Data of 2,283 patients (1,343 abiraterone; 940 placebo) from two phase 3 trials: COU-AA-301 and COU-AA-302 were meta-analyzed. Compared with placebo, abiraterone significantly prolonged OS (HR, 0.74; 95% confidence interval [CI], 0.66 to 0.84), RPFS (HR, 0.59; 95% CI, 0.48 to 0.74) and time to PSA progression (HR, 0.55; 95% CI, 0.43 to 0.70); it also significantly increased PSA response rate (RR, 3.63; 95% CI, 1.72 to 7.65) and objective response rate (RR, 3.05; 95% CI, 1.51 to 6.15). This meta-analysis suggested that the adverse events caused by abiraterone are acceptable and can be controlled. Conclutios: Abiraterone significantly prolonged OS, RPFS and time to progression patients with mCRPC, regardless of prior chemotherapy or whether chemotherapy-na$\ddot{i}$ve, and no unexpected toxicity was evident. Abiraterone can serve as a new standard therapy for mCRPC.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.89-95
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• 2006

A selective and sensitive reversed-phase HPLC method for the determination of pentoxifylline in human serum was developed, validated, and applied to the pharmacokinetic study of pentoxifylline. Pentoxifylline and internal standard, chloramphenicol, were extracted from the serum by liquid-liquid extraction with dichloromethane and analyzed on a Luna CI8(2) column with the mobile phase of acetonitrile-0.034 M phosphoric acid (25:75, v/v, adjusted to pH 4.0 with 10 M NaOH). Detection wavelength of 273 nm and flow rate of 0.8 mL/min were used. This method showed linear response over the concentration range of 10-500 ng/mL with correlation coefficients greater than 0.999. The lower limit of quantification using 0.5 mL of the serum was 10 ng/mL, which was sensitive enough for pharmacokinetic studies of pentoxifylline. The overall accuracy of the quality control samples ranged from 89.3 to 92.7% for pentoxifylline with overall precision (% C.V.) being 4.1-9.2%. The relative mean recovery of pentoxifylline for human serum was 105.8%. Stability (stock solution, short and long-term) studies showed that pentoxifylline was not stable during storage. But three freeze-thaw cycles and extracted serum samples were stable. This method showed good ruggedness (within 15% C.V.) and was successfully applied for the analysis of pentoxifylline in human serum samples for the pharmacokinetic studies of orally administered $Trental^{\circledR}$ tablet (400 mg pentoxifylline), demonstrating the suitability of the method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.154-164
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• 2016

This study analyzed the determinants of the turnover intention of emotion workers and recent social issues. In particular, this study examined whether the factors that determine the turnover intention affect the quality of service. The job characteristics of emotion workers were set up as an independent variable, and the job environment, organizational culture, such as emotional labor and how it affects the workers' behavior were investigated. How the independent variables influence the turnover of workers was investigated to mediate the emotional job satisfaction. The subjects were primarily targeted by the emotions of the workers engaged in large service accommodation, Kangwon. Among the environmental factors, the job characteristics and job duties are diverse factors and internal and external factors that can affect the compensation turnover intentions. Organizational culture as a factor was the human resources culture, open culture systems, and the hierarchical cultural factors affecting turnover intention. Among the emotional labor practices that also affects the surface of conduct, sincere acts influence the turnover intention. In addition, a one hypothesis testing job satisfaction was mediated by several factors with an impact, such as job diversity. Future empirical research should examined whether temporary full-time is an independent variable factor that can achieve a more fruitful conclusion.