• 한국건설순환자원학회논문집
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• 제11권4호
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• pp.535-541
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• 2023

Friction material, an integral constituent of bearing supports, facilitates frictional interactions between two components. Polytetrafluoroethylene (PTFE), a commonly employed friction material in bearing supports, has assessed resultant friction equilibrium. Nonetheless, protracted utilization diminishes frictional performance as the lubricating agent is progressively depleted. Friction materials can affect the entire structural system. Hence, this study applied ceramic material as a friction material due to its high strength, low friction, and low deformation. The frictional behavior was investigated using a cyclic friction test, considering various friction materials as the primary design variables and examining their covariance in cyclic frictional movements. The results substantiated that the ceramic friction material yielded a low variance and friction coefficients in cyclic frictional movements.

• Journal of Photoscience
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• 제9권2호
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• pp.74-77
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• 2002

Chlorophyll (Chi) d was assigned to an antenna pigment of red algae in 1943, but its presence and function in red algae have not been necessarily clear for a long time. In 1996, it was shown that Chi d functioned as a major antenna pigment in a peculiar oxygenic photosynthetic prokaryote, Acaryochloris marina, isolated as a symbiont of a colonial ascidian from coral reefs. This finding evoked the necessity for reexamination of the presence and function of Chi d in red algae. We found Chi d in methanol-extract from several marine red algae, and the relative content was high in one species, Ahnfeltiopsis flabelliformis. Absorption and fluorescence spectra, HPLC analysis, and NMR and mass spectroscopy characterized Chi d extracted from the red algal thalli, and those were essentially identical to those of Chi d isolated from A. marina. However, micro-spectrophotometric analysis suggested that Chi d was not an actual constituent of the red algae but came from epiphyte(s) attached to surface of red algal thalli.

• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.23-28
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• 2007

In this study, we analyzed the maximum output power characteristics of crystalline silicon photovoltaic module by change of environmental effects. The electrical, optical and thermal property of PV modules were investigated during outdoor test period about 70 days. There was a fluctuation in maximum output power by change in transmittance caused by environment effects like rain, snow and dust. The effects of external environmental change were analyzed using climate data. Also local thermal temperature variation and transmittance imbalance on surface of PV module which might lead degradation of constituent material were detected using infrared camera. The further analysis is describe in the following paper.

• Journal of Korean Dental Science
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• 제6권2호
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• pp.41-49
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• 2013

Purpose: This study sought to compare the elemental constitution, morphological characteristics, particle size distribution, biocompatibility, and mineralization potential of Ortho MTA (OMTA) and ProRoot MTA (PMTA). Materials and Methods: OMTA and PMTA were compared using energy-dispersive spectrometry, particle size analysis, and scanning electron microscopy. The biocompatibility and mineralization-related gene expression (osteonectin and osteopontin) of both MTAs were also compared using methylthiazol tetrazolium assay and reverse transcription-polymerization chain reaction analysis, respectively. The results were analyzed by Kruskal-Wallis test with Bonferroni correction. P-value of <0.05 was considered significant. Result: The morphology of OMTA powders was similar to that of PMTA. The constituent elements of both MTAs were calcium, silicon, and aluminum. The mean particle sizes of OMTA and PMTA were 4.60 and 3.34 mm, respectively. Both MTAs had equally favorable in vitro biocompatibility and affected the messenger RNA expression of osteonectin and osteopontin. Conclusion: Within the limitations of this study, OMTA could be a promising biomaterial in clinical endodontics.

• 한국대기환경학회지
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• 제9권1호
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• pp.61-68
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• 1993

Since November 1990, the observations of carbon dioxide$(CO_2)$ levels have been carried out at Tae-ahn Peninsula(TAP) in Korea. Analysis on atmospheric data obtained in the period from November 1990 to August 1992 is carried out and the results are included in this study. It is observed that variations of monthly average level on $CO_2$ are in the range of 315.72 $\sim$ 365.37ppm(amplitude 17.65ppm). The seasonal variation is large with a maximum occurring in March-April and with a minimum in July-August. A comparison of TAP data is made with data obtained at Ryori in Japan for 1991. The annual average value of TAP is 1.79ppm higher than that of Ryori. It is also found that in summer the minimum level of $CO_2$ at TAP is almost same as the $CO_2$ level occurring at Quinghai Province in China and at Ulaan Uul in Mongolia. Albeit, a maximum concentration of $CO_2$ at TAP is slightly higher than that of the same gas observed at other sites in spring. We interpret that TAP is generally under the influence of airflows coming from China. According to analysis of trajectories and airflows, we find the high values of $CO_2$ when an air flow is originated mainly from China and when an airflow is both of local(Korea) and of China origins. In contrast, when an airflow of maritime origin arrives, a low value of the atmospheric constituent is observed at TAP.

• 한국환경과학회지
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• 제22권4호
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• pp.397-406
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• 2013

With the methodology of AHP, this paper focuses on communication activities and their constituents in city parks, selecting 11 constituents, natural or artificial, and establishes an evaluation model on the basis of the analysis of the characteristics of tourists' communication activities in order to obtain the weight and order of importance of the constituents of communication activities space. First-grade indicators influence weight and the order of the constituents of communication activities space are: artificial constituents (0.6614) > natural constituents (0.3386). The weight and order of five secondary indicators attached to natural constituents: private space (0.1538) > shade tree (0.0955) > gentle slope mound (0.0474) > beautiful waterscape (0.0270) > sunshine lawn (0.0149); the weight and order of six secondary indicators attached to artificial constituents: field boundary (0.2865) > Leisure chairs (0.1843) > resting areas (0.0795) > appropriate square (0.0533) > tree-lined road (0.0352) > landscape sketch (0.0227).Using modern decision analysis methodology to research the relationship of environment constituent elements has great theoretical and practical significance for the scientific design and construction of suitable environment for human needs.

• 전기학회논문지
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• 제56권3호
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• pp.632-640
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• 2007

The low force estimation method of skeletal muscle was proposed by using ICA(independent component analysis) and neuro-transmission model. An EMG decomposition is the procedure by which the signal is classified into its constituent MUAP(motor unit action potential). The force index of electromyography was due to the generation of MUAP. To estimate low force, current analysis technique, such as RMS(root mean square) and MAV(mean absolute value), have not been shown to provide direct measures of the number and timing of motoneurons firing or their firing frequencies, but are used due to lack of other options. In this paper, the method based on ICA and chemical signal transmission mechanism from neuron to muscle was proposed. The force generation model consists of two linear, first-order low pass filters separated by a static non-linearity. The model takes a modulated IPI(inter pulse interval) as input and produces isometric force as output. Both the step and random train were applied to the neuro-transmission model. As a results, the ICA has shown remarkable enhancement by finding a hidden MAUP from the original superimposed EMG signal and estimating accurate IPI. And the proposed estimation technique shows good agreements with the low force measured comparing with RMS and MAV method to the input patterns.

• 생약학회지
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• 제38권4호
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• pp.327-333
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• 2007

The chemical composition of the volatile constituents from the leaves, stems, and roots of Acanthopanax senticosus growing wild in Mt. Deok-Yu was determined by GC and GC/MS spectrometric analysis with the aid of NBS, Wiley Library and RI indice searches. The major constituents identified were ${\delta}-elemene\;(23.14%),\;{\beta}-elemene\;(5.59%),\;{\gamma}-cadinene\;(5.43%),\;and\;{\alpha}-bergamotene\;(28.54%)$ in the leaves, ${\alpha}-pinene\;(11.50%),\;{\delta}-elemene\;(17.62%),\;{\alpha}-bergamotene\;(27.21%)$, and bicycloheptane derivative (6.38%) in the stems, and ${\alpha}-pinene\;(21.90%)$, and (+)-aromadendrene (3.77%) in the roots.

• Journal of Nutrition and Health
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• 제25권2호
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• pp.140-149
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• 1992

It was hypothesized that variations within the range of usual calcium(Ca) and sodium(Na) intakes of Korean influence bone mineral density(BMD) in healthy premenopausal women The relationship of nutrient intake urinary excretion physical activity and circulating IGF-1 level with spine({{{{ { L}_{2 } }}}}-{{{{ { L}_{4 } }}}}) and femur BMD was determined in 47 normal premenpausal women. There was a positive relationship between BMD of the lumbar spine and body weight. The BMD of femoral neck was positively correlated with Ca and protein intakes from animal source and circulating IGF-1 level. There was a negative relationship between femur BMD and both Na intake and urinary excretion. The complex interrelations between femur BMD regression analysis, From this analysis. Ca intake from animal origin was the only significnat Premenopausal women of femur BMD. In the basis of femur BMD three groups were divided Premenopausal women of femur BMD$\leq$0.84g/cm2 showed depressed Ca intake of animal origin in later and early life and enhanced urinary Na excretion compared to women of femur study suggests that dietary Ca is a major constituent affecting femur BMD because of a decrease in net Ca absorption and an increase in urinary Ca loss.

• 대한화학회지
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• 제26권5호
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• pp.320-325
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• 1982

황을 분석하기 위하여 준비한 용액을 이용하여 황화광석중 철, 구리, 코발트를 X-선 형광법으로 정량하였다. 시료를 $Br_2$ 와 $HNO_3$의 혼합용액으로 녹인 다음 HF로 처리하여 주성분인 $SiO_2$를 제거한 다음 용액으로 만들었다. 분석결과는 철함량이 20 ~ 50%에서 ${\pm}$1.5%, 구리 함량이 10 ~ 15%에서 ${\pm}$1.0%, 코발트함량이 1 ~ 5% 범위에서 ${\pm}$0.4% 이내로 다른 습식분석법의 data와 일치하고 있으며 재현성에 있어서도 좋은 결과를 얻었다.