• 한국정밀공학회지
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• 제27권2호
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• pp.94-101
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• 2010

Composite materials have a higher specific strength and modulus than traditional metallic materials. Additionally, these materials offer new design flexibilities, corrosion and wear resistance, low thermal conductivity and increased fatigue life. These, however, are susceptible to impact damage due to their lack of through-thickness reinforcement and it causes large drops in the load-carrying capacity of a structure. Therefore, the impact damage behavior and subsequently load-carrying capacity of impacted composite materials deserve careful investigation. In this study, the residual strength and impact characteristics of plain-woven CFRP composites with impact damage are investigated under axial tensile test. Impact test was performed using drop weight impact tester. And residual strength behavior by impact was evaluated using the caprino model. Also we evaluated behavior of residual strength by change of mass and size of impactor. Examined change of residual strength by impact energy change through this research and consider impactor diameter in caprino model.

• 디지털융복합연구
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• 제17권12호
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• pp.109-115
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• 2019

본 연구의 목적은 전기 매출액 변동이 연구개발비 및 각 세부항목에 미치는 영향에 대하여 검증을 실시하고 전기매출액 변동 시 경영진들이 어떠한 의사결정을 수행하는지를 분석하는 것이다. 분석을 실시하기 위하여 선행연구에서 주로 사용되었던 Anderson et al.(2003)의 1기간 모형뿐만 아니라 보다 심도 깊은 분석을 실시하기 위하여 Banker et al.(2014)의 2기간 모형을 이용하여 연구개발비 및 각 세부항목에 대한 분석을 실시하였다. 분석결과 1기간 모형에서는 모형의 한계로 인하여 감가상각비, 기타에서만 하방경직적 원가행태를 확인할 수 있었다. 보다 심층적인 분석을 위하여 2기간 모형으로 분석한 결과 전기 매출액이 증가하는 경우 인건비, 기타 항목에서 하방경직적인 원가행태를 나타내었으나 총 연구개발비는 역 하방경직적인 원가행태를 나타내었다. 전기 매출액이 감소하는 경우 위탁용역비에서 하방경직적인 원가행태가 나타났다. 본 연구는 기존 연구에서 수행되지 않았던 연구개발비 및 세부항목에 대하여 전기 매출액 변동이 원가행태에 미치는 영향을 분석하였기에 그 의의가 있다. 더 나아가 추후 연구에서 매출별, 산업별로 보다 구체적인 연구를 할 수 있을 것이라 기대한다.

• 한국직업건강간호학회지
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• 제13권2호
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• pp.140-147
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• 2004

Purpose: The purpose of this study is to identify the types of worksite health promotion programs. Method: Data were collected from the excellent 35 cases chosen at the contest for worksite health promotion held by Korea Occupational Safety and Health Agency. Result: Out of all the health promotion programs, the exercise program recorded 35.0%, the nutrition program 29.4%, the smoking cessation program 28.0%, and the alcohol reduction program 7.6%. The major element of worksite health promotion programs were awareness raising intervention. Behavior change intervention and supportive environment intervention occupied a small portion of the health promotion programs. Evaluation of health promotion programs was made mainly by indicators of health behavior change and clinical symptom. Yet economical indicator was not used at all. Conclusion: Use of various evaluation indicator and development of various interventions including behavior change and supply of supportive environment are required to encourage worksite health promotion program.

• Journal of Magnetics
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• 제18권1호
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• pp.30-33
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• 2013

The magnetocaloric effect and magnetization behavior have been analyzed in the double-perovskite $La_{0.7}Ba_{0.3}Mn_{1-X}Fe_XO_3$ compound with the sintering temperature at 1273 K. Samples were fabricated by the conventional solid-state reaction method. X-ray diffraction measurement revealed that all the samples had a single phase in orthorhombic. Detailed investigations of the magnetic entropy behavior of the samples were discussed with the variation of $T_C$. The magnetic entropy changes, ${\Delta}S_M$ of approximately 0.36-1.14 J/kg K were obtained in the temperature range of 145-350 K for the $La_{0.7}Ba_{0.3}Mn_{1-X}Fe_XO_3$ compound. The enhancement of the magnetic entropy change is believed to be due to changes in the microstructure, which changes the magnetic part of the entropy of a solid around the magnetic ordering temperature.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2005년도 추계학술대회 논문집
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• pp.365-368
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• 2005

This paper describes the implementation of autonomy in the motion of a small size human robot. Traditional modeling of environment and concept of moving planning have limitations to adapt the change of environment and to implement in real-time operation. To overcome these limitations, we designed a behavior-based control algorithm and applied to robot soccer. Based on experiment, we verify that the behavior-based control algorithm works well in the change of environment.

• Fibers and Polymers
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• 제2권2호
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• pp.81-85
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• 2001

The effects of rate of phase separation to ester interchange reactions and the repulsive pair interaction energy on the phase behavior in a phase-separated immiscible polyester blend are investigated using a Monte Carlo simulation method. The time evolution of structure factor and the degree of randomness are monitored as a function of homogenization time. When the phase separation is dominant over ester interchange reactions, the domain size slowly increases with homogenization time. However, when the pair interaction becomes less repulsive, the domain size does not significantly change with homogenization time. On the other hand, when ester interchange reactions are dominant over the phase separation, the homogenization proceeds without a change in the domain size. The higher the extent of phase separation, the lower the increasing rate of the DR. However, when the phase separation is sufficiently dominant, the effect of the extent of phase separation on the increasing rate of the degree of randomness become less significant.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.104-108
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• 1993

Thin films of MgO-doped and CaO-doped iron oxide were prepared y spray pyrolysis. The films were characterized b X-ray diffraction, scanning electron microscopy and voltammetric techniques. The photoelectrochemical behavior of thin film electrodes depended greatly on the doping level, sintering temperature, substrate temperature and added photosensitizing compounds in solution, showed p-type photoelectrochemical behavior, while the CaO-doped iron oxide thin films prepared at low temperature showed n-type photoelectrochemical behavior. This characteristic change was interpreted in terms of the surface structure change of the thin films and doping effect of metal oxide.

• Korean Chemical Engineering Research
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• 제56권1호
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• pp.14-23
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• 2018

The effect of dodecylbenzene sulfonic acid (DBSA) with different addition amount of DBSA ($M_{DBSA}$), temperatures and solvent-to-oil ratio (SOR, v/v) on asphaltene aggregation in a solvent deasphalting system was investigated. Increasing the $M_{DBSA}$ at SOR 10 and $55^{\circ}C$ caused the asphaltene removal ratio (ARR) to increase first, then maximize at 1 wt% of $M_{DBSA}$ and then decrease continuously. Based on the SARA (saturate, aromatic, resin, asphaltene) composition, the adsorption amount of DBSA on the asphaltene surface and the self-aggregation of the DBSA, the reason for the change in ARR with $M_{DBSA}$ was found due to the adsorption mechanism. In addition, the asphaltene-resin-DBSA colloidal size confirmed the change of adsorption behavior between the asphaltene and DBSA. Based on the results of this study, a hypothetical adsorption mechanism of DBSA on asphaltene aggregation in the solvent deasphalting system was conceived of and proposed.

• Journal of Nutrition and Health
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• 제34권4호
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• pp.449-457
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• 2001

This study was performed to show change of fat-free mass(FFM), representing mostly the muscle mass change, and muscle strength with increasing age, and relationship between dietary, exercise behaviors and FFM in healthy middle-and old aged women who are of age over 55 years. The FFM and correspondingly hand grip strength showed significant positive correlation with age. But concentration of serum albumin showed no significant relationship with age. The subjects were categorized into groups according to FFM tertile. The anthropometry such as weight, BMI, fat mass, circumferences of waist and hip, WHR, and hand grip strength decreased significantly in the lowest FFM group. But the albumin level showed no change according to FFM level. The FFM showed significant correlation with nutrient intakes such as energy, carbohydrate, protein, Fe, P, Ca. No association, however, was shown with exercise behavior probably because of no case with resistance exercise habits. The variance of FFM was explained 55.2% by height and carbohydrate intake. The variance of height-adjusted FFM could be explained only 16.2% by intake amount of carbohydrate. In conclusion, the decrease of FFM may cause to reduce muscle strength in female elderly. The increasing nutrient intakes were associated with the increased FFM and may protect from risk of sarcopenia. However, only the carbohydrate intake could influence independently the FFM in middle- and old-aged women. The FFM has no association with endurance exercise habits. (Korean J Nutrition 34(4) : 449∼457, 2001)

• The Korean Journal of Ceramics
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• 제3권2호
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• pp.101-104
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• 1997

Although tribological behavior of Si incorporated DLC films have been intensely investigated, their mechanical properties were not consistent among previous publications. The present work reported the structural change by adding Si, and their effects on the mechanical properties. Si incoporated DLC films were deposited using mixtures of benzene and diluted silane with hydrogen of various volume fractions. We could obtain the films of $X_{si}$ (defined by the Si fraction without considering hydrogen) ranging from 0.01 to 0.21, and found that the mechanical properties of the films changed significantly in the range less than $X_{si}=0.06$. In this range, the hardness and stress increased with Xsi. For higher content of Si, the hardness and stress showed saturated behavior with $X_{si}$. This behavior was discussed in terms of the changes in atomic bond structures.