• 성인간호학회지
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• 제18권4호
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• pp.543-552
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• 2006

Purpose: The purpose of this descriptive study was to investigate the pattern of physical restraints used in ICUs and to identify influencing factors of application and removal of restraints. Method: The subjects of this study were 90 restrained patients out of 215 patients over 6 years old who were admitted to 6 ICUs in SMC during a 2 weeks period. The data was collected through a questionnaire of characteristics, guidelines and nursing care of restraint uses. The data were analyzed by non-parametric statistic with the use of the SAS program. Results: The restraints were applied to 31.4% of subjects. Mean time of physical restraint was $36.76{\pm}55.7$ hours. There were significant difference with mean time and frequency according to duty shift. GCS, restless behavior and discomfort factors, medical devices, and life sustaining devices had significant relation with application of restraints. In addition, the mean time of restraints used were related significantly with GCS, restless behavior, and discomfort factors. Conclusion: The used of restraints were dependent on mainly the nurses' decision. Thus ICU nurses have to develop the guidelines to applying restraints and removal of restraints in regard to patients rights and ethics. Continuous monitoring and evaluation of application of the restraints is essential in professional nursing.

• 동력기계공학회지
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• 제21권6호
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• pp.13-20
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• 2017

Ni-base superalloy Haynes 282 was developed as a gas turbine material for use in the ultra-super-critical stage (USC) of next-generation coal-fired power plants. Temperatures in the USC stage exceed $700^{\circ}C$ during operation. In spite of its important role Haynes 282 in increasing the performance of high-pressure turbines, as a result of its high-temperature capability, there is little information on the microstructure, deformation mechanism, or mechanical properties of the cast condition of this alloy. The aim of present study is to examine the creep properties of cast alloy and compare with wrought alloy. The ${\gamma}^{\prime}-precipitates$ were coarsen with the increase of aging time ranging from 8 to 48 hrs. A creep test performed at $750^{\circ}C$ showed faster minimum creep rate and shorter rupture lifetime with the aging time. A creep test performed showed only a slight difference in the rupture life between cast and wrought products. Based on the creep test results, the deformation mechanism is discussed using fractographs.

• 한국생산제조학회지
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• 제9권3호
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• pp.150-159
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• 2000

In-process diagnosis of the cutting state is essential for the automation of manufacturing systems. Especially when the cutting process becomes unstable it induces self-exited vibrations a frequent case of poor tool life rough surface finish damage to the workpiece and the machine tool itself and excessive down time. To ensure that the cutting process main-tains stable it is highly desirable to have the capability of real-time. To ensure that the cutting process main-tains stable it is highly desirable to have the capability of real-time monitoring and controlling chatter. This paper describes the detection method of chatter vibration using cutting force in turning process. In order to detect a chatter vibra-tion the dynamic fluctuation of radial force is analyzed since this components is sensitive to the chatter. The envelope sig-nal of radial force has been calculated by the use of FIR Hilbert transformer and it was useful to classify the chatter signal from the dynamically unstable circumstances. It was found that the mode and the mode width were closely correlated with the chatter amplitude was well. Finally back propagation(BP) neural network have been applied to the pattern recognition for the classification of chatter signal in various cutting conditions. The validity of this systed was confirmed by the experiments under the various cutting conditions.

• 품질경영학회지
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• 제48권1호
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• pp.69-86
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• 2020

Purpose: This study aims to determine the optimal conditions for the spot welding process that mechanically connects the case of a cylindrical secondary battery and the negative tab. Methods: We use 33 factorial design to derive the optimal conditions for the spot welding process. The pulling strength, the cross-sectional area of nugget, and the shock test life are selected as response variables, which can represent the resistance welding quality. The input variables are selected as the welding time, welding voltage, and pressure, which are the controllable factors in the spot welding process. Results: The main effects of welding time and welding voltage and the interaction effect of welding time and welding voltage are significant. Conclusion: The optimal conditions for the spot welding process to mechanically join the negative electrode tab of the cylindrical secondary battery and the battery case are developed. The result shows that the pulling strength is increased by 44% compared to before improvement under optimal conditions.

• 대한교통학회:학술대회논문집
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• 대한교통학회 2000년도 제37회 학술발표회논문집
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• pp.25-47
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• 2000

In route guidance systems fastest-path routing has typically been adopted because of its simplicity. However, empirical studies on route choice behavior have shown that drivers use numerous criteria in choosing a route. The objective of this study is to develop computationally efficient algorithms for identifying a manageable subset of the nondominated (i.e. Pareto optimal) paths for real-time vehicle routing which reflect the drivers' preferences and route choice behaviors. We propose two pruning algorithms that reduce the search area based on a context-dependent linear utility function and thus reduce the computation time. The basic notion of the proposed approach is that ⅰ) enumerating all nondominated paths is computationally too expensive, ⅱ) obtaining a stable mathematical representation of the drivers' utility function is theoretically difficult and impractical, and ⅲ) obtaining optimal path given a nonlinear utility function is a NP-hard problem. Consequently, a heuristic two-stage strategy which identifies multiple routes and then select the near-optimal path may be effective and practical. As the first stage, we utilize the relaxation based pruning technique based on an entropy model to recognize and discard most of the nondominated paths that do not reflect the drivers' preference and/or the context-dependency of the preference. In addition, to make sure that paths identified are dissimilar in terms of links used, the number of shared links between routes is limited. We test the proposed algorithms in a large real-life traffic network and show that the algorithms reduce CPU time significantly compared with conventional multi-criteria shortest path algorithms while the attributes of the routes identified reflect drivers' preferences and generic route choice behaviors well.

• 산경연구논집
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• 제13권7호
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• pp.37-45
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• 2022

Purpose: Leisure time is an intrinsic part of the work-life balance that enables people to rejuvenate their energy and provides a platform to maintain their health while sustaining their productivity levels. The purpose of this study is to investigate the effects of changes in leisure consumption culture on the modern economy through various research materials. Research design, data and methodology: To have completeness in published systematic reviews and meta-analyses, the use of the standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist is essential and the present research selected this research design. Results: This research figured out that individuals who spend most of their leisure time watching TV have been shown to experience lesser satisfaction in their job designation and less happiness overall and also found that Leukocyte Telomere Length is influenced by the type of leisure an individual engages in. Conclusions: Overall, this research points out that the income effect may provide an inverse relationship between work time and labor in that high income from labor makes an individual less inclined to work to make the same money they made before the increased benefits. It is a narrative that may need further research in finding the principles that govern leisure in the labor force.

• 한국표면공학회지
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• 제56권1호
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• pp.84-93
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• 2023

The spent nuclear fuel is burned during the planned cycle in the plant and then generates elements such as actinide series, fission products, and plutonium with a long half-life. An 'interim storage' step is needed to manage the high radioactivity and heat emitted by nuclides until permanent-disposal. In the case of Korea, there is no space to dispose of high-level radioactive waste after use, so there is a need for a period of time using interim storage. Therefore, the intensity of neutrons and gamma-ray must be determined to ensure the integrity of spent nuclear fuel during interim storage. In particular, the most important thing in spent nuclear fuel is burnup evaluation, estimation of the source term of neutrons and gamma-ray is regarded as a reference measurement of the burnup evaluation. In this study, an analysis of spent nuclear fuel was conducted by setting up a virtual fuel burnup case based on CE16×16 fuel to check the total amount and spectrum of neutron, gamma radiation produced. The correlation between BU (burnup), IE (enrichment), and CT (cooling time) will be identified through spent nuclear fuel burnup calculation. In addition, the composition of nuclide inventory, actinide and fission products can be identified.

• 한국산학기술학회논문지
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• 제19권9호
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• pp.261-268
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• 2018

전력수요와 부하용량이 증가 되어감에 따라 부하에 전력공급을 위한 간선으로서의 케이블은 설치 시간의 과다와 공간의 제약으로 사용이 제한적이다. 이런 문제를 해결하기 위한 간선 시스템으로 대전류를 효율적으로 공급해 줄 수 있는 버스웨이 시스템의 사용이 증가되고 있으나, 신뢰성의 검증을 위한 시험평가 방법과 그에 대한 결과 제시가 부족한 실정이다. 본 논문에서는 에폭시를 주절연으로 하는 버스웨이 시스템의 신뢰성 검증을 위해서 IEC 61439-6에서 제시된 시험항목이외에 장기 사용성과 신뢰성을 평가할 수 있는 시험항목을 선정하였다. 열 및 전기적 스트레스를 동시에 인가하여 최대한 실사용 상태를 반영한 복합가속열화시험을 실시하였으며, 50년 수명 조건을 충족하도록 열화 조건을 선정하여 버스웨이 시스템의 절연성능 확인시험을 통해 수명을 만족함을 확인하였다. 또한, 버스웨이가 설치되는 온도, 습도 및 부하전류 사용 환경에 대한 적합성 확인에 대한 신뢰성 평가 시험항목으로서 열적 과전류 시험, 침수시험, 냉충격시험, 온도 사이클 시험을 선정하여 실시하였으며, 확인 시험을 통해 시험 전후의 특성 변화와 이상 유무를 검토하였다. 이 결과들로부터 에폭시 절연형 버스웨이 시스템의 평가항목으로서 본 논문에서 제시한 시험항목이 적절하고, 그에 대한 제품의 성능도 우수함을 확인하였다.

• 생명과학회지
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• 제31권4호
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• pp.430-441
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• 2021

세스퀴테르펜 락톤(Sesquiterpene lactones; STL) 화합물은 테르페노이드의 일종으로 주로 국화과에서 발견이 되고 강한 세포 독성을 나타내는 생리학적 특성을 지니고 있다. 이러한 세스퀴테르펜 락톤은 강한 세포 독성으로 인해 연구가 미미하였으나, 최근 화학적 변형을 통해 독성이 적은 형태로 합성하여 새로운 의약품 개발로서의 연구가 활발히 진행되고 있다. 세스퀴테르펜 락톤 화합물인 artemisinin 및 mipsagargin 화합물은 현재 말라리아 및 종양성장에 대한 약물로 사용되고 있다. 또한 항산화, 간보호, 항바이러스, 항균, 항종양 및 항노화 등의 생리활성 효능이 보고되어 있으며, 종양세포에서 자멸사를 유도하여 항암제로서의 연구가 진행되고 있다. 본 연구에서는 세스퀴테르펜 락톤 화합물인 artemisinin, costunolide, thapsigargin, arglabin, parthenolide, alantolactone, cynaropicrin, helenalin, 및 santonin의 생리활성 효능에 대한 연구 동향을 검토하고자 한다.

• 한국식품저장유통학회지
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• 제16권6호
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• pp.908-914
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• 2009

본 연구에서는 프로폴리스의 다양한 효능을 이용한 식품 소재 개발을 위해 반응표면분석을 이용하여 프로폴리스의 에탄올 추출농도(50, 60, 70, 80, 90%)와 추출시간에 따른 항산화능, 플라보노이드 등의 품질특성을 조사하였다. 총 페놀성 화합물 함량은 에탄올 농도가 높을수록 증가하다가 80% 이상에서는 감소하는 것으로 나타났으며, 추출시간보다는 에탄올 농도에 더 큰 영향을 받는 것으로 나타났다. 추출물의 전자공여능은 에탄올 농도가 높을수록, 추출시간이 짧을수록 전자공여능이 증가하였으며, 추출시간보다는 에탄올농도에 더 큰 영향을 받는 것으로 나타났다. 항산화능이 가장 높은 범위는 에탄올 농도 65~75%, 추출시간 2.2~3.6시간이었다. 추출물의 아질산염소거능은 에탄올농도가 높을수록 증가하였고, 추출시간이 짧을수록 증가하는 경향을 나타내었다. 총 플라보노이드 함량은 에탄올 농도 68~82% 및 추출시간 2.4~3.7시간 범위에서 최대 함량을 나타내었으며, 에탄올 농도 및 추출시간 모두에 영향을 받는 것으로 나타났다. 에탄올 농도, 추출시간에 따른 반응표면을 superimposing하여 얻은 프로폴리스의 최적 추출조건의 범위는 에탄올 농도 72-82%, 추출시간 2.2-3.3시간 범위인 것으로 나타났다.