• Safety and Health at Work
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• 제1권1호
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• pp.19-28
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• 2010

Industrial Safety and Health Law (ISH Law) of Japan requires abnormalities identified in evaluations of worker health and working environments are reported to occupational physicians, and employers are advised of measures to ensure appropriate accommodations in working environments and work procedures. Since the 1980s, notions of a risk assessment and occupational safety and health management system were expected to further prevent industrial accidents. In 2005, ISH Law stipulated workplace risk assessment using the wording "employers shall endeavor." Following the amendment, multiple documents and guidelines for risk assessment for different work procedures were developed. They require ISH Laws to be implemented fully and workplaces to plan and execute measures to reduce risks, ranking them from those addressing potential hazards to those requiring workers to wear protective articles. A governmental survey in 2005 found the performance of risk assessment was 20.4% and common reasons for not implementing risk assessments were lack of adequate personnel or knowledge. ISH Law specifies criminal penalties for both individuals and organizations. Moreover, under the Labor Contract Law promulgated in 2007, employers are obliged to make reasonable efforts to ensure employee health for foreseeable and avoidable risks. Therefore, enterprises neglecting even the non-binding provisions of guidelines are likely to suffer significant business impact if judged to be responsible for industrial accidents or occupational disease. To promote risk assessment, we must strengthen technical, financial, and physical support from public-service organizations, encourage the dissemination of good practices to reduce risks, and consider additional employer incentives, including relaxed mandatory regulations.

• Nuclear Engineering and Technology
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• 제40권1호
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• pp.21-36
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• 2008

High bum-up fuel technology has been developed through a national R&D program, which covers key technology areas such as claddings, $UO_2$ pellets, spacer grids, performance code, and fuel assembly tests. New cladding alloys were developed through alloy designs, tube fabrication, out-of-pile test and in-reactor test. The new Zr-Nb tubes are found to be much better in their corrosion resistance and creep strength than the Zircaloy-4 tube, owing to an optimized composition and heat treatment of the new Zr-Nb alloys. A new fabrication technology for large grain $UO_2$ pellets was developed using various uranium oxide seeds and a micro-doping of Al. The uranium oxide seeds, which were added to $UO_2$ powder, were prepared by oxidizing and heat-treating scrap $UO_2$ pellets. A $UO_2$ pellet containing tungsten channels was fabricated for a thermal conductivity enhancement. For the fuel performance analysis, new high burnup models were developed and implemented in a code. This code was verified by an international database and our own database. The developed spacer grid has two features of contoured contact spring and hybrid mixing vanes. Mechanical and hydraulic tests showed that the spacer grid is superior in its rodsupporting, wear resistance and CHF performance. Finally, fuel assembly test technology was also developed. Facilities for mechanical and thermal hydraulic tests were constructed and are now in operation. Several achievements are to be utilized soon by the Korea Nuclear Fuel and thereby contribute to the economy and safety of PWR fuel in Korea

• PNF and Movement
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• 제13권1호
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• pp.47-53
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• 2015

Purpose: This study examined the effects of space fabric type air insole pressure differences on young adults' dynamic balance ability. Method: The subjects of this study were 17 young female adults without musculoskeletal system disease. Balance ability was measured by dividing the subjects into three groups: an experimental group which did not wear an air insole (insole-off group), an experimental group which wore an air insole to which air pressure of $0.55kg/cm^2$ was applied (insole-0.55 group), and an experimental group which wore an air insole to which air pressure of $0.75kg/cm^2$ was applied (insole-0.75 group). For dynamic balance, the subjects stood on a balance pad, and perimeter length and medium speed were measured three times. The averaged values were recorded and statistically processed. Result: There were significant differences in average speed, and the insole-0.75 group's average speed decreased compared to the insole-off group and the insole-0.55 group. Although the total movement distance did not statistically differ, the insole-75 group's movement distance decreased compared to the insole-off group and the insole-0.55 group. Conclusion: Application of a space fabric type air insole, in particular insole-0.75, was helpful in improving balance ability. This is considered to occur because the space fabric structure was conducive to decreasing sway and producing balance.

• Tribology and Lubricants
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• 제37권4호
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• pp.129-135
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• 2021

An air-bearing stage uses externally pressurized air as the lubricant between the stage and the rail. The supporting force generated by the supplied air makes the stage rise and move smoothly with extremely low friction. Mechanical contacts rarely happen, the bearing surfaces do not produce wear particles, and dust is not generated. It also has the advantage of having low energy loss and high precision. Because of its advantages, an air-bearing stage is used in several types of machines that require high precision. In this article, the effect of the pocket depth on the hammering phenomena of the air bearing is studied. An analysis program is developed to calculate the dynamic behavior of the stage by solving the Reynolds equation between the stage and the guideway and the equations of motion on the stage. The acceleration, constant movement, and deceleration are applied to the stage. The stage is modeled as a five-degree-of-freedom system. In the course of the dynamic behavior, the hammering phenomena occur under some special conditions. The deeper the pocket, the more unstable the behavior of the stage, and air hammering occurs when it exceeds a certain depth. In addition, the higher the supply pressure, the more unstable the behavior of the stage. However, hammering occurs even with a shallow pocket depth. Other conditions that affect the hammering phenomena are calculated and discussed.

• 융합정보논문지
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• 제11권12호
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• pp.80-89
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• 2021

2020년 1월 30일, 세계보건기구(World Health Organization)는 COVID-19의 확산이 "국제보건규정(International Health Regulations)" 제1조에 규정된 "국제적 공중보건 비상사태(Public Health Emergency of International Concern)"의 기준을 충족한다고 선언하고, 팬데믹 퇴치를 위한 다양한 예비 권고를 제안하였다. 이후 3월부터 팬데믹이 본격화되면서 (일부 국가에서는 마스크 착용이 법으로 금지되었음에도 불구하고) 갑자기 공공장소에서 마스크를 쓰라는 지시가 내려졌다. 경제·사회 환경이 예상치 못한 방향으로 바뀌면서 법조계에서도 화상심리 도입 등 조금씩 변화의 바람이 불기 시작했다. 아마도 COVID-19 이후에는 이전의 일상과는 매우 다른 모습으로 변화될 가능성이 크다. COVID-19가 국제중재 진행방식에도 영향을 미치고 있는바 관건은 이러한 영향이 몇 년 동안만 지속되는 일시적인 문제로 그칠 것인지, 아니면 COVID-19의 확산이 국제중재 진행방식의 전환점이 될 것인지가 의문이다. 이러한 이해를 바탕으로 본 연구는 COVID-19가 국제중재에 미치는 영향 및 효과를 고찰하고, 향후 전망을 제시한다.

• Tribology and Lubricants
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• 제37권4호
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• pp.144-150
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• 2021

The most cost-effective method of reducing abrasive wear in mechanical parts is increasing their hardness with thin hard coatings. In practice, the composite hardness of the coated substrate is more important than that of the substrate or coating. After full unloading of the load applied to an indenter, its indentation hardness evaluated based on the dent created on the test piece was almost dependent on plastic deformation of the substrate. Following the first part of this study, which proposes a new Brinell hardness test method for a coated surface, the remainder of the study is focused on practical application of the method. Indentation analyses of a rigid sphere and elastic-perfect plastic materials were performed using finite element analysis software. The maximum principal stress and plastic strain distributions as well as the dent shapes according to the substrate yield stress and coating thickness were compared. The substrate yield stress had a significant effect on the dent size, which in turn determines the Brinell hardness. In particular, plastic deformation of the substrate produced dents regardless of the state of the coating layer. The hardness increase by coating behaved differently depending on the substrate yield stress, coating thickness, and indentation load. These results are expected to be useful when evaluating the composite hardness values of various coated friction surfaces.

• 한국방사선학회논문지
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• 제15권6호
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• pp.841-847
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• 2021

방사선을 이용하는 관련 기관은 국내에 연구, 의료, 교육 등 다양하다. 최근에는 검진 및 의료기관의 방문 횟수가 증가하고 있다. 이로 인해 의료기관에서 방사선학적 검사 횟수가 증가하고 있다. 방사선작업종사자의 피폭뿐만 아니라 방사선 안전관리가 필요하다. 안전관리를 위해서 우선적으로 개인피폭선량계의 올바른 착용 및 착용 후 정확한 측정이 필요하다. 본 연구는 진단용 방사선발생장치의 방사선에 의한 PLD 소자의 계측 직선성을 평가하고 검증하려고 한다. 방사선 분할 조사 시간간격은 10, 30, 60 sec로 10회 조사와 거리에 따라 흡수선량 변화를 측정하기 위해서 조사거리를 30 ~ 100 cm까지 10 cm 간격으로 조사 후 측정하였다. 그 결과 시간 간격에 의한 흡수선량은 차이가 없었다. 이는 고흡수선량 연구에 진단용발생장치를 이용하여 다양한 연구에 도움이 될 것으로 여겨진다.

• 한국의류산업학회지
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• 제23권5호
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• pp.624-633
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• 2021

This study was intended to compare the comfort of wearing each type of commercially available bralette. The trial wearing experiment was conducted on five women in their 20s who wear an average Korean bra size of 70A. The experimental bralettes were of four types: a bralette with both hooks and pads and a bralette without both, a bralette with hooks but no pads, and a bralette with pads but no hooks. The wearing test results are as follows. First, in terms of functional satisfaction, the padded bralette provided the greatest satisfaction in supporting the chest from the bottom up and bringing it to the center, and the bralette without the pad provided the least satisfaction. In addition, the level of convenience of attaching/detaching was about twice as high in the bralette with hooks than those without hooks. Chest compression was found to be greater in bralettes without hooks than in those with hooks. In terms of the pressure on the shoulder strap and on the lower chest band, it was found that bralettes with hooks had a greater sense of pressure than those without. In the appearance characteristics test, the unpadded bralettes scored higher than the padded one in the matter of feeling embarrassed, because in unpadded bralettes, the nipples were exposed underneath the clothes . This study is meaningful in classifying the design of the bralette and evaluating the fit for each design in the absence of prior research on the bralette.

• Corrosion Science and Technology
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• 제20권1호
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• pp.26-36
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• 2021

Pipes operating in the seawater environment faces cavitation degradation and corrosion of the metallic component, as well as a negative synergistic effect. Cavitation degradation shows the mechanism by which materials deteriorate by causing rapid change of pressure or high-frequency vibration in the solution, and introducing the formation and explosion of bubbles. In order to rate the cavitation resistance of materials, constant conditions have been used. However, while a dynamic cavitation condition can be generated in a real system, there has been little reported on the effect of ultrasonic amplitude on the cavitation resistance and mechanism of composites. In this work, 3 kinds of epoxy coatings were used, and the cavitation resistance of the epoxy coatings was evaluated in 3.5% NaCl at 15 ℃ using an indirect ultrasonic cavitation method. Eleven kinds of mechanical properties were obtained, namely compressive strength, flexural strength and modulus, tensile strength and elongation, Shore D hardness, water absorptivity, impact test, wear test for coating only and pull-off strength for epoxy coating/carbon steel or epoxy coating/rubber/carbon steel. The cavitation erosion mechanism of epoxy coatings was discussed on the basis of the mechanical properties and the effect of ultrasonic amplitude on the degradation of coatings.

• 한국융합학회논문지
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• 제12권12호
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• pp.117-123
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• 2021

본 연구의 목적은 인솔구두의 굽 높이에 따른 평발을 가진 20대 대학생의 보행 시 발목관절의 각도변화에 대해 융복합적 비교를 하는 것이다. 15명의 대학생을 대상으로 동작분석기(Qualisys Track Manager)를 이용하였다. 인솔이 장착된 기능성 구두를 제작하고, 구두의 굽 높이를 0cm, 3cm와 7cm로 셋팅하였다. 실험대상자들은 두 개의 굽 높이가 있는 구두를 신고 발목관절의 측면에 반사마커를 부착하여 보행을 실시하였다. 보행입각기에서 발목관절의 각도변화를 측정하였다. 평발을 가진 실험대상자가 인솔구두를 착용 시 구두 굽 높이가 높을수록 양측의 Heel strike, Foot flat, Midstance, Toe off에서 유의한 감소가 나타났다. 따라서 평발을 가진 대상자는 인솔구두를 착용 시 낮은 구두를 신어야만 발바닥의 피로를 감소시켜 편안한 보행을 할 것으로 사료된다.