• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.361-363
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• 2003

To reduce the effect of fault on underground power cable, we need exact and fast fault location detection technique. In this thesis, we describe on filter design technique that can be applied to on-line fault defection technique. To design fitter for fault location defection on Power cable, we should analysis fault signal. So we designed test bed for fault generation and measured fault signals for analysis. Through the analysis of signals, we found that ANC filter can be applied to separate fault signals and we designed a ANC filter. We tested on the designed filter through computer simulation, and we describe its results in this paper.

• 비파괴검사학회지
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• 제23권3호
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• pp.270-279
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• 2003

Parametric studies have been conducted into the variability of the factors affecting the ultrasonic testing applied to weldments. The influence of ultrasonic equipment, transducer parameters, test technique, job parameters, defect type and characteristics on reliability far defect detection and sizing was investigated by experimentation. The investigation was able to build up substantial bank of information on the reliability of manual ultrasonic method for testing weldments. The major findings of the study separate into two parts, one dealing with correlation between ultrasonic techniques, equipment and defect parameters and inspection performance effectiveness and other with human factors. Defect detection abilities are dependent on the training, experience and proficiency of the UT operators, the equipment used, the effectiveness of procedures and techniques.

• The Journal of Advanced Prosthodontics
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• 제14권5호
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• pp.273-284
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• 2022

PURPOSE. Computer-aided design and manufacturing (CAD-CAM) of implant abutments has been shown to result in surface contamination from site-specific milling and fabrication processes. If not removed, these contaminants can have a potentially adverse effect and may trigger inflammatory responses of the peri-implant tissues. The aim of the present study was to evaluate the bacterial disinfection and cleaning efficacy of ultrasonic reprocessing in approved disinfectants to reduce the microbial load of CAD-CAM abutments. MATERIALS AND METHODS. Four different types of custom implant abutments (total N = 32) with eight specimens in each test group (type I to IV) were CAD-CAM manufactured. In two separate contamination experiments, specimens were contaminated with heparinized sheep blood alone and with heparinized sheep blood and the test bacterium Enterococcus faecium. Abutments in the test group were processed according to a three-stage ultrasonic protocol and assessed qualitatively and quantitatively by determination of residual protein. Ultrasonicated specimens contaminated with sheep blood and E. faecium were additionally eluted and the dilutions were incubated on agar plates for seven days. The determined bacterial counts were expressed as colony-forming units (CFU). RESULTS. Ultrasonic reprocessing resulted in a substantial decrease in residual bacterial protein to less than 80 ㎍ and a reduction in microbiota of more than 7 log levels of CFU for all abutment types, exceeding the effect required for disinfection. CONCLUSION. A three-stage ultrasonic cleaning and disinfection protocol results in effective bacterial decontamination. The procedure is reproducible and complies with the standardized reprocessing and disinfection specifications for one- or two-piece CAD-CAM implant abutments.

• 한국학교보건학회지
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• 제18권2호
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• pp.105-119
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• 2005

Purposes： This study was to examine the effects of empowerment education programs on empowerment and mental health in high school students. Methods： This study involved a nonequivalent control group pre-test and post-test design. The subjects for this study consisted of 421 high school students who attended two general high schools in Busan. The 211 students in the experimental group received empowerment education training, while the 210 students in the control group did not. The data were collected from March 2, 2004 to July 20, 2004. The empowerment education program consisted of 17 separate 50-minute sessions. The questionnire was developedby authors and revised it based on experts' advice. SPSS 11.0 program was used to analyze the data. Chi-square test and t-test were used to test the homogeneity of general characteristics and dependent variables. Student's t-test was used to evaluate the differences between the experimental group and control group after the treatment. Results： Just as we hypothesized, the experimental group exhibited higher empowerment scores than the control group. For subcategory, Score of self-efficacy and self-esteem increased significantly in the experimental group compared to the control group. However, the score of decision-making ability did not increase significantly. The data failed to support our second hypothesis that the experimental group would have higher mental health scores than the control group. Although the score of self-scale increased significantly in the experimental group compared to the control group, the score of social-support and psychopathology did not. Conclusions： Empowerment education programs are effective for empowerment of high school students. However, such training is effective only for promoting the self scale but not overall mental health. Thus, we suggest the application of the empowerment education program to make high school students aware of their abilities. Furthermore, we suggest the implementation of mental health programs to supplement such empowerment education programs.

• 대한기계학회논문집B
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• 제28권3호
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• pp.349-358
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• 2004

A low pressure impactor is an impaction device to separate airborne particles into aerodynamic size classes at low pressure condition. We designed a two-stage low-pressure impactor to classify submicron sized environmental aerosols. Performance evaluation was carried out for stages 1 and 2 by using an electrical method. Monodisperse liquid dioctyl sebacate (DOS) particles were generated using evaporation-condensation process followed by electrostatic classification using a DMA (differential mobility analyzer). The test particles were in the range of 0.08∼0.8$\mu\textrm{m}$. For the evaluation of the impactor we used two electrometers; one was connected to the impaction plate of the impactor and the other was to the Faraday cage used as a backup filter. The effect of polydispersity of test aerosols on the performance was investigated. The results showed that the experimental 50-% cutoff diameters at each impactor's operation pressure were 0.53 and 0.187$\mu\textrm{m}$ for stages 1 and stage 2, respectively. The effects of operation pressure on the cutoff diameter and the steepness of collection efficiency curves were also investigated.

• Nuclear Engineering and Technology
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• 제38권1호
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• pp.45-60
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• 2006

Presently, the VHTGR (Very High Temperature Gas-cooled Reactor) is considered the most attractive candidate for a GEN-IV reactor to produce hydrogen, which will be a key resource for future energy production. A new concept for a reactor cavity cooling system (RCCS), a critical safety feature in the VHTGR, is proposed in the present study. The proposed RCCS consists of passive water pool and active air cooling systems. These are employed to overcome the poor cooling capability of the air-cooled RCCS and the complex cavity structures of the water-cooled RCCS. In order to estimate the licensibility of the proposed design, its performance and integrity were tested experimentally with a reduced-scale mock-up facility, as well as with a separate-effect test facility (SET) for the 1/4 water pool of the RCCS-SNU to examine the heat transfer and pressure drop and code capability. This paper presents the test results for SET and validation of MARS-GCR, a system code for the safety analysis of a HTGR. In addition, CFX5.7, a computational fluid dynamics code, was also used for the code-to-code benchmark of MARS-GCR. From the present experimental and numerical studies, the efficacy of MARS-GCR in application to determining the optimal design of complicated systems such as a RCCS and evaluation of their feasibility has been validated.

• 한국표면공학회지
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• 제34권2호
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• pp.125-134
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• 2001

($Ti_{1-x}$ $Cr_{x}$ )N coatings were deposited by an ion-plating method in a reactor with two separate metal sources, Ti and Cr. Ti was evaporated using an electron beam, while Cr evaporation was carried out by resistant heating. The Ti and Cr concentrations in the coatings were controlled by the Ti and Cr evaporation ratio. The coating hardness increased with increasing the Cr content(x) and showed a maximum value of 6,000 HK at around x=0.8. The critical load of the coatings, measured by the scratch test, was around 30 N. The wear resistance properties of the ($Ti_{1-x}$$Cr_{ x}$)N coatings were evaluated using a CSEM pin-on-disk type tribometer. A Cr-steel ball as well as a SiC ball, which had hardness values of 590 HK and 2,600 HK respectively, were used as the pin. After the wear test, the surface morphology, roughness and the concentration of the coatings were investigated, with the main focus being on the effect of wear debris and the transferred layer on the wear behavior.

• 한국건축시공학회지
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• 제14권2호
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• pp.163-169
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• 2014

Engineers in the construction field have been using bonded waterproofing sheets in an attempt to resolve the imbalance in the quality, the risk of fire, safety of workers, and environmental pollution, as well as to eliminate separate use of organic adhesives on the surface of concrete. Recently, self-laminated waterproofing sheets have been developed. The purpose of this research is to find an appropriate processing speed according to the changes in physical properties, and visual observation of the waterproofing sheets laminated by the aluminum thin-film and viscosity layer that can be attached through self-adhesiveness on the surface of concrete and waterproofing sheets. Therefore, this research is conducted using a physical performance test. Based on the result of the test, when the high-frequency inductive heating apparatus was used, an improved adhesion and bonding stability effect were confirmed after the anti-hydrostatic pressure and bond strength in the temperature condition, and the surface observation in the processing speed condition.

• 약학회지
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• 제58권5호
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• pp.300-306
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• 2014

Ethanol consumption causes psychomotor alterations. Hovenia Semen seu Fructus (HS), widely distributed in Korea, China, and Japan, has been reported to have beneficial effects on acute alcohol-induced liver injury. The present study sought to assess the effects of HS extract on ethanol-induced psychomotor alterations in rats. Sprague-Dawley rats were orally (p.o.) given ethanol (4 g/kg) (ethanol group) to induce psychomotor alterations. A separate group (HS-treated groups), were treated with different dosages of HS (50, 100, and 200 mg/kg, p.o.), 30 minutes before ethanol treatment. The control group received only the vehicle (saline). Ethanol-induced psychomotor alterations were evaluated in the open-field, rota-rod, hanging wire, and cold swimming test. In addition, blood ethanol and acetaldehyde concentrations were also measured. Behavioral evaluations and blood analysis were carried out 0.5, 1, 2, 4, and 8 hours after ethanol administration. Pre-treatment of HS ameliorated ethanol-induced alterations in the open-field, rota-rod, and cold swimming test, significantly evident in 2 and 4 hours after ethanol treatment. These improvements coincided with decrease in blood ethanol and acetaldehyde concentration. Based on these results, the present study suggests that HS may have ameliorating effects against ethanol-induced psychomotor alterations.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.683-693
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• 2021

Shipping has become an important sector in supporting social, economic, government, defense, security, cultural and other sectors to unite separate islands and broad seas. Thus, ports automatically become an important facility in Indonesia. The purpose of this research is to test and explain the effect of Organizational readiness for change, Service Innovation, and Corporate Image on Perceived opportunity and challenge. The research model with inferential analysis uses Structural Equation Modeling (SEM) analysis with the WarpPLS approach, expected to answer the statements of problem and be able to test the desired hypothesis. The model development in this research was based on the background, statements of problem, conceptual framework and research hypotheses. The model referred to is "Complete and Comprehensive Port." Its development was carried out through studying and synthesizing various sources. The most important source is the results of literature review in the form of theoretical developments and research results, then continued with compilation. The use of Organizational Change Readiness, Service Innovation, and Corporate Image in improving Port Competitiveness is seen as one of the novelties of this research, specifically the use of the Organizational Change Readiness variable which is often used in high-flexibility companies but now used in port companies as well.