• 태양에너지
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• 제5권2호
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• pp.28-34
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• 1985

There are two kinds of irradiation intensity deviation, depending on time and position, on illuminated plane when thermal performance of solar collector is tested by using solar simulator. In this study we measured only position deviation of irradiation intensity using 45-cds photosensors and data acqusition system and found the point of average value. By this result we can improve the accuracy of irradiation measurement in indoor test of solar collector.

• Bulletin of the Korean Chemical Society
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• 제6권1호
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• pp.33-36
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• 1985

The luminescence intensity of $Tb^{3+}$ bound to picolinic acid, squaric acid, and 2,3-pyrazinedicarboxylic acid has been studied in water and water-ethanol mixtures. It has been found that the emission intensity of $Tb^{3+}$ in the complexes is enhanced with the increase of ethanol content in water-ethanol mixtures. Several factors affecting on the emission intensity of $Tb^{3+}$ in waterethanol mixtures are discussed.

• 태양에너지
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• 제20권1호
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• pp.21-29
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• 2000

본 연구에서는 하루중의 각 시간별로 서로 다른 경사각도별로 수광면에 입사하는 태양에너지의 강도를 실측을 통하여 정량적인 검토와 분석이 가능하도록 측정된 데이터를 기술자료화하고, 각각의 날별로 일사량 강도가 유사한 날들을 그룹화하기 위하여 시간별 일사량 변화에 따른 다항회귀모형을 일별로 산출하고, 각 날별로 서로 비교하기 위해 일별로 산출된 다항회귀모형의 두 그래프사이의 면적을 계산하여 면적의 차가 거의 없는 날들을 일사량 강도가 유사한 날들로 그룹화하는 기법을 개발하여, 월별 또는 전년을 통하여 이들 그룹을 모형별로 제시한다. 또한 다시 이들 모형별로 태양에너지 이용시스템의 효율을 최대화 할 수 있는 시스템 최적경사각도를 제시하여 해당 지역에 적합한 시스템의 최적 설계기준을 제시하고자 한다.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1244-1249
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• 2024

A combination of flow-accelerated corrosion (FAC) tests and corresponding computational fluid dynamics (CFD) tests were performed to determine the hydrodynamic parameters that could help predict the highly susceptible location to FAC in the elbow section. The accelerated FAC tests were performed on a specimen containing elbow sections fabricated using commercial 2-inch carbon steel pipe. The tests were conducted at flow rates of 9 m/s under the following conditions: water temperature of 150 ℃, dissolved oxygen <5 ppb, and pH 7. Thickness reduction of the specimen pipe due to FAC was measured using ultrasonic testing. CFD was conducted on the FAC test specimen, and the turbulence intensity, and shear stress were analyzed. Notably, the location of the maximum hydrodynamic parameters, that is, the wall shear stress and turbulent intensity, is also the same location with maximum FAC rate. Therefore, the shear stress and turbulence intensity can be used as hydrodynamic parameters that help predict the FAC-induced wall-thinning rate. The results provide a method to identify locations susceptible to FAC and can be useful for determining inspection priority in piping systems.

• 대한지역사회영양학회지
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• 제22권5호
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• pp.413-425
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• 2017

Objectives: Accurate assessment of energy expenditure is important for estimation of energy requirements in athletic children. The objective of this study was to evaluate the accuracy of accelerometer for prediction of selected activities' energy expenditure and intensity in athletic elementary school children. Methods: The present study involved 31 soccer players (16 males and 15 females) from an elementary school (9-12 years). During the measurements, children performed eight selected activities while simultaneously wearing the accelerometer and carrying the portable indirect calorimeter. Five equations (Freedson/Trost, Treuth, Pate, Puyau, Mattocks) were assessed for the prediction of energy expenditure from accelerometer counts, while Evenson equation was added for prediction of activity intensity, making six equations in total. The accuracy of accelerometer for energy prediction was assessed by comparing measured and predicted values, using the paired t-test. The intensity classification accuracy was evaluated with kappa statistics and ROC-Curve. Results: For activities of lying down, television viewing and reading, Freedson/Trost, Treuth were accurate in predicting energy expenditure. Regarding Pate, it was accurate for vacuuming and slow treadmill walking energy prediction. Mattocks was accurate in treadmill running activities. Concerning activity intensity classification accuracy, Pate (kappa=0.72) had the best performance across the four intensities (sedentary, light, moderate, vigorous). In case of the sedentary activities, all equations had a good prediction accuracy, while with light activities and Vigorous activities, Pate had an excellent accuracy (ROC-AUC=0.91, 0.94). For Moderate activities, all equations showed a poor performance. Conclusions: In conclusion, none of the assessed equations was accurate in predicting energy expenditure across all assessed activities in athletic children. For activity intensity classification, Pate had the best prediction accuracy.

• 생명과학회지
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• 제18권10호
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• pp.1455-1463
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• 2008

The purpose of this study was to evaluate the effect of various exercise intensity on Excess post exercise energy expenditure (EPEE), Resting Metabolic Rate (RMR),thyroid hormonal changes and biochemical variables in obese and NIDDM patients. The subject of the present study were divided into four groups and four periods: trained (T; n=10), control (C; n=10), obese (O; n=10) and NIDDM (N; n=10) group. And the periods were divided as follows; Resting (RE), Maximal (MA), High intensity (HI), and Low intensity (LI). There was significant difference in RMR among different intensity of exercise. in the T (p<0.05) not in the C, O, and N groups. however, there was no significant different percent body fat among all groups. In the energy expenditure, there was significant different among C, O, N groups compare to T in HIEE (high intensity exercise energy expenditure), LIEE (low intensity exercise energy expenditure), HIEEPE (high intensity exercise energy expenditure post exercise) and LIEEPE (low intensity exercise expenditure post exercise). In the hormonal level, there was significant different in T4 level in the T group at LI period and there was also significant difference in T4, Free T3, & Free T4 levels in T group at LI period, however there was no significant different in the O and N groups except LI period. In the fatigue variables, there was significant different in lactate and ammonia levels in the N group in the period of HI compare to C. The present cross-sectional study was design to investigate the relationship between exercise intensity and RMR in four groups. The focus of this investigation was to compare RMR in aerobically trained (T), control (C), obese (O) and NIDDM (N) group. The relationship among RMR, exercise intensity and percent body fat would best be investigated using Meta Lyzer 3B, MMX3B and body composition analyzer. Each subject completed measurement of percent body fat, RMR, hormone in the period of maximal oxygen uptake exercise (MA), high intensity exercise (HI), and low intensity exercise (LI). From the results, High and Low intensity of exercise, there was a trend for an increased RMR (kcal/day) in the trained groups and control group (in case of LI) not for the obese and N groups. This is best explained not by the reduced percent body fat but by the highly induced energy expenditure (during exercise and post exercise energy expenditure) and increased T4, Free T3, and Free T4 hormonal levels in the low intensity exercise for the T group and sometimes C group.

• 대한기계학회논문집
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• 제19권1호
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• pp.170-180
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• 1995

A parallel crack in bonded dissimilar orthotropic planes under out-of-plane loading is analyzed. The problem is formulated by Fourier integral transforms, and reduced to a pair of dual integral equations. By solving the integral equations, the asymptotic stress and displacement fields near the crack tip are determined in closed form, from which the stress intensity factor and energy release rate are obtained. Discontinuity in the stress intensity factor as the distance ratio h/a of the parallel crack approaches zero is found, while the energy releas rate is shown to be continuous at h/a = 0. This information can immediately be used to generate the stress intensity factor for the parallel crack near the interface. By employing "the maximum energy release rate criterion", it could be shown in the case of no existing crack initially that the parallel crack is formed far from the interface for the more compliant material, while it is formed close to the interface for the stiffer material. material.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.301-308
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• 2000

The power flow analysis(PFA) has been performed to analyze the vibration of coupled plates excited by a point force in an arbitrry direction. The energy governing equations for longitudinal, shear and flexural waves were solved to predict the vibrational energy density and intensity. The wave transmission approach was used to consider the mode conversion at the joints of the coupled plates. Numerical results for energy density and intensity on the coupled plates were presented. Comparison of the results by PFA with exact results showed that PFA can be an effective tool to predict the spatial variation of the vibrational energy and intensity on the coupled plates at high frequencies.

• 자원ㆍ환경경제연구
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• 제10권4호
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• pp.569-589
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• 2001

We examine historical contributions of inter fuel substitution, changes in carbon efficiency and energy intensity, growth of economy and population to Korea's $CO_2$ emissions from 1970 to 1998 using the log mean weight Divisia index method. The study reveals that economic growth is the most significant factor to $CO_2$ emissions growth among the five factors. Changes in the fuel substitution and carbon coefficient are found negative contributors to $CO_2$ emissions growth. Energy intensity, which played dominant role in halting $CO_2$ emissions growth in the 1980s, began to play reversed role in the 1990s. When evaluated with the log mean Divisia index technique, deterioration of energy intensity in the 1990s is found worse and expected to contribute $CO_2$ emissions growth further.

• 전기학회논문지
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• 제65권7호
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• pp.1225-1230
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• 2016

Since a flash light produces enormous amount of photon energy in short time, not only electro-optic and infrared(EO/IR) systems utilized for Intelligence Surveillance Target Acquisition and reconnaissance(ISTAR) activities but also the people of a combat field can be severely influenced by a high flash light bursting in front of them. The people who bumped into a flash could not escape such enormous amount of photon energy, resulting in being blind temporarily or even permanently. In order to investigate the effect of a high flash source on a human eye, it is essential to know how much photon energy be incident into an eye from the flash source. In this paper, the model of irradiated photon energy to individuals from some flashes is proposed. The proposed irradiated photon energy per unit area of retina is based on taking the situation to be modeled as a simple EO system in front of a flash light. The validity of proposed model was proved by the application of the model to human on the surface of the earth with the well known light source, the Sun. The model of this study can be utilized to simulate the retinal intensity and energy of a flash for various conditions such as the illumination levels, the distance from a flash busting site, luminous intensity and time of a flash.