• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2001-2006
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• 2009

Temperature dependence of the critical micelle concentration (CMC), $x_{CMC}$, in micellization can be described by ln $x_{CMC}$ = A + BT + C lnT + D/T, which has been derived statistical-mechanically. Here A, B, C, and D are fitting parameters. The equation fits the CMC data better than conventionally used polynomial equations of temperature. Moreover, it yields the unique(exponent) value of 2 when the CMC is expressed in a power-law form. This finding is quite significant, because it may point to the universality of the thermal behavior of CMC. Hence, in this article, the nature of the equation ln $x_{CMC}$ = A + BT + C lnT + D/T is examined from a lattice-theory point of view through the Flory-Huggins model. It is found that a linear behavior of heat capacity change of micellization is responsible for the CMC equation of temperature.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1407-1412
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• 2003

In MEMS devices, packaging induced stress or stress induced structure deformation become increasing concerns since it directly affects the performance of the device. In this paper, deformation behavior of MEMS gyroscope package subjected to temparature change is investigated using high-sensitivity $Moir{\acute{e}}$ interferometry. Using the real-time $Moir{\acute{e}}$ setup, fringe patterns are recorded and analyzed at several temperatures. Temperature dependent analyses of warpages and extensions/contractions of the package are presented. Linear elastic behavior is documented in the temperature region of room temperature to $125^{\circ}C$. Analysis of the package reveals that global bending occurs due to the mismatch of thermal expansion coefficient between the chip, the molding compond and the PCB.

• 한국안전학회지
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• 제16권2호
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• pp.91-96
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• 2001

Theoretical definitions of mixed behavior of PE panel and connote should have preceded to cause a mixed behavior of connote and polyethylene which have different elastic module, one-line expansion coefficients, poison ratios, compressive strengths and tensile strengths. Consequently, changes are analyzed through experiment process to identify the effects on interpretation of mixed behavior on the basis of temperature change of structures, temperature rise of concrete other than PE panel due to hydration heat temperature rise of concrete other than PE panel due to drying and contraction, working of hydrostatic pressure by storage and temperature gradient From the results of interpretation of the analysis, it is concluded that PE panel have slight influences on the change of guess of structures and maintains structural stability compared with concrete structures without PE panel.

• 한국항공운항학회지
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• 제27권4호
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• pp.96-104
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• 2019

The response to climate change of international air transport industry might be initiated by ICAO's CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) which will impact on international airlines' flight operation behavior in the future. Though the airlines' efforts to reduce fuel consumption has been a major issue in economics of aviation industry, the improvement of fuel efficiency in flight operation will have additional impact on their profitability by introducing carbon emission cost. The fuel consumption in flight operation will be somewhat influenced by pilots' technical action for maneuvering aircraft during flight operation. This study will investigate pilots' behavior on decision for tactical aircraft control for mission flight. The data will be collected by the survey through sample pilots asking about their intention and perception on fuel savings during flight operations. The data will be analyzed by AHP process and the study will find out the elements and factors influencing pilots' behavior on technical decision of flight and their weights on fuel saving effects.

• 대한수학회지
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• 제58권3호
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• pp.723-740
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• 2021

Design and maintenance of large span roof structures require an analysis of their static and dynamic behavior depending on the physical parameters defining the structures. Therefore, it is highly desirable to estimate the parameters from observations of the system. In this paper we study the parameter estimation problem for damped shallow arches. We discuss both symmetric and non-symmetric shapes and loads, and provide theoretical and numerical studies of the model behavior. Our study of the behavior of such structures shows that it is greatly affected by the existence of critical parameters. A small change in such parameters causes a significant change in the model behavior. The presence of the critical parameters makes it challenging to obtain good estimation. We overcome this difficulty by presenting the Parameter Estimation Algorithm that identifies the unknown parameters sequentially. It is shown numerically that the algorithm achieves a successful parameter estimation for models defined by arbitrary parameters, including the critical ones.

• 근관절건강학회지
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• 제22권3호
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• pp.167-176
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• 2015

Purpose: The purpose of this study was to identify the level of body perception, obesity, and factors associated with stages of exercise and dietary habits change in university students. Methods: A descriptive design was used. Data were collected from 279 university students using structured questionnaires. Results: The body perception was significantly associated with self rated health (F=27.89. p<.001), weight satisfaction (F=137.74. p<.001) and weight control interest (F=39.19. p<.001). The BMI was significantly associated with weight satisfaction (F=34.08. p<.001) and weight control interest (F=19.59. p=.003). But the body perception and BMI were not significantly associated with depression (F=2.17, p=.073, F=0.86. p=.462), the change of exercise (F=25.91. p=.055, F=20.34. p=.061), and dietary habits (F=12.96. p=.677, F=11.29. p=.505). The related factors affecting the change of exercise behavior were counter conditioning, self efficacy, eating behavior, and helping relationship, including 30.4% R-square. The related factor affecting the change of dietary habit was only eating behavior, including 20.0% R-square. Conclusion: This study can provide useful information to develop effective programs for the change of exercise and dietary habits considering university students' stages of change according to the transtheoretical model.

• 융합정보논문지
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• 제7권6호
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• pp.35-43
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• 2017

본 연구의 목적은 교대근무 간호사의 운동행위변화단계에 미치는 융합적 영향요인을 분석하는데 있다. 연구대상자는 병원에 근무하는 교대근무 간호사로 연구의 목적을 이해하고 연구에 참여할 것을 동의한 120명의 간호사이다. 연구 자료는 빈도, 백분율, 평균, 표준편차, t-test, $X^2$ test, 다중 로지스틱 회귀분석을 이용하여 분석하였다. 교대근무 간호사의 운동행위변화단계에 유의한 영향을 미치는 요인은 운동 동기(${\beta}=2.480$, p=.022), 건강상태 지각(${\beta}=1.151$, p=.013), 사회적지지(${\beta}=1.819$, p=.002)와 결혼유무(${\beta}=-1.820$, p=.004)로 나타났다. 즉, 운동행위 변화가 있는 대상자가 운동행위 변화가 없는 대상자에 비해 운동 동기가 11.9배 높고, 건강상태 지각은 3.1배 높았으며 사회적 지지는 6.1배, 미혼인 대상자는 기혼인 대상자에 비해 .16배 높았다. 그러므로 교대근무간호사의 운동행위 변화단계에 영향을 미치는 요인이 운동동기와 사회적지지, 건강상태 지각인 점을 고려하여 지속적이고 규칙적인 운동을 실천하기 위한 전략을 개발하는 것이 중요하다.

• 한국문헌정보학회지
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• 제51권4호
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• pp.161-181
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• 2017

본 연구는 모바일 건강 애플리케이션을 활용하여 건강행위를 변화시키는 건강정보소비자 들이 그 역동적인 단계적 변화에 따라 추구하는 건강정보 탐색행태를 관찰하고자 하였다. 이를 위해 본 연구는 변화단계모형(Stages of change)을 이론적 틀로 사용하여 각 단계에서 나타나는 건강정보소비자들의 인식, 정보요구 및 탐색행태의 변화를 분석하였다. 본 연구에는 총 30명의 대학생 이용자들이 참여하여 3개월 동안 건강 애플리케이션을 사용하면서 금연, 금주, 및 규칙적 운동 등의 건강행위의 변화를 시도하였으며, 그들의 경험을 바탕으로 서면인터뷰를 실시하였다. 연구결과에 따르면, 연구 참여자들은 소셜 미디어와 인터넷을 포함하여 다양한 정보원을 사용할 뿐 아니라 정보요구에 따라 상이한 정보원을 탐색했다. 특히, 실행단계에 접어든 소비자들의 본격적인 건강 앱 활용에서 나타나는 정보요구와 정보탐색행태는 특별히 건강 앱을 통한 건강정보서비스의 함의를 시사한다. 또한, 행위변화를 시행하면서 경험하는 스트레스 관리와 퇴보(relapse), 그리고 행위변화의 긍정적 및 부정적 효과는 건강정보제공자에게 소비자의 건강행위변화를 지원할 수 있는 통찰력을 제공한다.

• 소성∙가공
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• 제19권4호
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• pp.236-241
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• 2010

The frictional behavior of bare steel sheet highly depends on surface roughness. It was investigated that the change of surface roughness of bare steel sheet due to deformation for each forming mode. The flat type friction test was done to check the effect of surface roughness change on frictional characteristics of bare steel sheet. As increasing the deformation, the Ra value was increased at stretching forming mode and drawing forming mode, however the change of Pc showed different trends. The Pc was decreased as increasing stretch deformation but increased at compression deformation. At drawing forming mode, the friction coefficient was increased as deformation was increased after initial big drop with drawing oil. As deformation was increased, the friction coefficient was decreased with drawing oil at stretching forming mode. The results show that the deformation changes the surface roughness and frictional characteristics of steel sheet but the effect depends on the forming mode.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.36-41
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• 2001

In this work, the changes in the friction force(lateral force) with respect to nanoscale geometric variation were investigated using an Atomic Force Microscope and a Lateral Force Microscope. It could be concluded that the changes in the friction force correspond well to the slope change rather than the surface slope itself, and that the influence of slope change on the frictional behavior is dependent on the magnitude of the slope and the torsional stiffness of the cantilever. Also, the nominal friction force is found to be more significantly affected by the material and the physical-chemical state of the surface rather than by nanoscale geometric steps. However, the change in nanoscale geometric details of the surface cause instantaneous change and slight variation in the friction signal.