• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.3
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• pp.303-314
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• 1998

In this study, the performance of a multi-stage condensation heat pump was examined. Computer simulation programs were developed for 1-stage, 2-stage, and 3-stage heat pumps and R11, R123, R141b were tested as working fluids. The results showed that coefficients of performance(COPs) of an optimized 3-stage condensation heat pump are 25∼40% higher than those of a conventional 1-stage heat pump. The increase in COP, however, differed among the fluids tested. The improvement in COP largely stems from the decrease in average LMTD values in the condensers of the multi-stage system. For the 3-stage condensation heat pumps, optimized UA values of three condensers were determined to be 30∼40% of the UA value of the total condenser regardless of the working fluid. When the amount of cooling water entering into the intermediate and high-stage subcoolers is roughly 10% of the total condenser cooling water respectively, the optimum performance was achieved for the 3-stage condensation heat pump.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.6
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• pp.526-554
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• 2014

Industrial engineering has played a central role in creating knowledge on quality control and reliability engineering (Q&R) and delivering such knowledge to various industries. This special issue paper is prepared in celebration of the $40^{th}$ anniversary of the Korean Institute of Industrial Engineers (KIIE), and includes discussions on how Q&R areas have evolved over almost 100 years and on the current domestic and international trends of Q&R activities in industry as well as in academia. To identify academic research trends, all Q&R related papers published in the Journal of the Korean Institute of Industrial Engineers (JKIIE) and IE Interfaces are examined and classified according to their research topics. Recent Q&R related papers published in IIE Transactions are also examined and classified in a similar manner, and the papers published in KIIE journals are compared with those in IIE Transactions with respect to the research areas emphasized, yearly trend of each research area, type of systems studied, research approaches and methodologies adopted, etc. In addition, quality control activities in domestic industries are evaluated based on a recent survey conducted by Korea Productivity Center, and for domestic reliability engineering activities, government-led projects and their accomplishments over the past decade are introduced. Based on the above, recommendations are made for the future directions of academic research and Q&R activities in industry.

• Journal of Korean Academy of Nursing
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• v.40 no.5
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• pp.676-685
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• 2010

Purpose: The purpose of this study was to examine the factors affecting eating attitude of female undergraduates according to BMI. Methods: A descriptive survey design with a convenience sampling was used and data collection was done using a self-report questionnaire answered by 406 female undergraduates from four universities located in Seoul, Kangwon, Gyeongsangbuk and Chungcheongnam Provinces. ANOVA, Pearson correlation coefficients, and hierarchial multiple regression were used the SPSS WIN 17.0 Program to analyze the data. Results: With respect to BMI, the students were found to be in 3 groups, whose differences in eating attitude were significant. Eating attitude had significant positive correlation with height (r=.118, p=.017), weight (r=.267, p<.000), BMI (r=.239, p<.001), and depression (r=.375, p<.001), and negative correlation with subjective well-being (r=-.153, p=.002) and body esteem (r=-.287, p<.001). In the hierarchial multiple regression analysis, college major, height, weight and religion, were controlled. Depression and body esteem regarding weight significantly predicted 40.7% of eating attitude for the underweight group and normal weight group, body esteem: weight and depression were significant predictors for 27.5% of eating attitude for the normal weight group. Body esteem: weight explained 32.6% of eating attitude for the overweight group. Conclusion: Findings of this study allow a comprehensive understanding of eating attitudes and related factors among female undergraduates in Korea. Further study with a larger random sample from various universities is necessary.

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.05a
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• pp.40-41
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• 1990

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.790-792
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• 2005

In this work we attempted to find the origin of brightness non-uniformity in SLS poly-Si TFT AMOLED. By developing a suitable SLS process with a compensation circuit, we have successfully improved the non-uniformity from 40% to 1.7%. We could fabricate 2.2" AMOLED display using SLS poly-Si.

• Korean journal of applied entomology
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• v.21 no.4 s.53
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• pp.191-194
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• 1982

Using the two different trunk-implantation methods, the systemic insecticides omethoate $(Folimat^{(R)}\;50\;EC)$, vamidothion $(Kilval^{(R)}\;40\;EC)$, methamidophos $(Tamaron^{(R)}\;60\;SL)$, phosphamidon $(Dimecron^{(R)}\;50\;EC)$, monocrorotophos $(Nuvacron^{(R)}\;24\;EC)$, dimethoate $(Rogor^{(R)}\;50\;EC)$, and phosalone$(Rubitox^{(R)})$ were evaluated for the control of the pine gall midges(Thecodiplosis japonensis Uchida et Inouye). Except phosalone, all the insecticides tested in this experiment were very effective for the suppression of the gall incidence by the insects. There was no significant difference in effectiveness between the conventional drilling and improved Mauget methods, and trunk-implantation of the insecticides by the improved Mauget method seemed to be much more feasible in practical view points of the labor cost saving the recovery of the holes drilled.

• Research in Plant Disease
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• v.9 no.2
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• pp.68-71
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• 2003

Correlation between rice yield loss and infection time of neck blast after panicle emergence was analyzed in paddy fields at Icheon in 1999 and 2000. As the neck blast occurred at early heading stage, the yield loss of a early maturity variety, Jinmibyeo, ranged from 83.9% to 81.6%, while it ranged from 44.3% to 33.1% when the disease developed 30 days after heading. The regression equations of yield loss(y) caused by the neck blast infection time(x) in Jinmibyeo were y =1.2717x + 79.523(R2 = 0.9487) and y = 1.6872x + 74.545(R2 = 0.7993) in 1999 and 2000. In a mid-lately maturity variety, Chucheongbyeo, yield loss ranged from 64.9% to 47.8% when the disease developed at early heading stage. While it ranged from 29.1% to 8.9% when the disease occurred 40 days after heading. The regression equations of yield loss caused by the disease in Chucheongbyeo were y= 1.2717x + 79.523($R^2$ = 0.9487) and y = 1.6872x + 74.545(($R^2$ = 0.7993) in 1999 and 2000. Weights of 1,000 rice grains of Jinmibyeo and Chucheongbyeo were also drastically decreased to 38.3% and 57.3%, respectively, compared to healthy control when the disease occurred at early heading stage. However, weights of the two cultivars were 87.6% and 92.9% compared to control when the disease developed after 40 days of heading. Results indicated that there is a highly negative correlation between rice yield loss and infection time of the neck blast.

• Membrane Journal
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• v.21 no.2
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• pp.127-140
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• 2011

The effects of $TiO_2$ photocatalyst coating bead concentration, water-back-flushing period (FT), and back-flushing time (BT) were investigated in hybrid process of ceramic ultrafiltration and photocatalyst for advanced drinking water treatment in this study. Photocatalyst coating bead concentration was changed in the range of 10~40 g/L, FT in 2~10 min and BT in 6~30 sec. Then, we observed the effects on resistance of membrane fouling $(R_f)$, permeate flux (J) and total permeate volume $(V_{\Upsilon})$ during total filtration time of 180 min. As decreasing photocatalyst coating bead concentration, $R_f$ increased and J decreased. $V_{\Upsilon}$ was the highest value of 8.85 L at 40 g/L of photocatalyst coating bead concentration. At FT change experiment, $R_f$ decreased and J increased as decreasing FT. Then $R_f$ decreased and J increased according to increasing BT at BT change experiment. Because at NBF (no back-flushing) dramatic membrane fouling reduced membrane pore size, turbid and dissolved organic matters ($UV_{254}$ absorbance) could be removed efficiently. Therefore, treatment efficiencies of turbidity and dissolved organic matters were the highest at NBF. Then by cleaning effect of photocatalyst coating bead, the treatment efficiencies of turbidity and dissolved organic matters increased as decreasing FT and increasing BT.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.173-181
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• 2021

Reinforced concrete structures are exposed to various environments, resulting in reinforcement corrosion due to moisture and ions penetration. Reinforced concrete corrosion causes a decrease in the durability performance of reinforced concrete structures. One solution to mitigate such issues is using FRP rebars, which offer several advantages such as high tensile strength, corrosion resistance, and light-weight than conventional rebars, in reinforced concrete instead of conventional steel rebars. The FRP rebar used should be examined at the limit state because FRP reinforced concrete has linear behavior until its fracture and can generate excessive deflection due to the low elastic modulus. It should be considered while designing FRP reinforced concrete for flexure. In the ultimate limit state, the flexural strength of FRP reinforced concrete as per ACI 440.1R is significantly lower than the flexural strength by applying both the environmental reduction and strength reduction factors accounting for the material uncertainty of FRP rebar. Therefore, in this study, the experimental results were compared with the deflection of the proposed effective moment of inertia referring to the local and international standards. The experimental results of GFRP and BFRP reinforced concrete were compared with the flexural strength as determined by ACI 440.1R and Fib bulletin 40. The flexural strength obtained by the experimental results was more similar to that obtained by Fib bulletin 40 than ACI 440.1R. The flexural strength of ACI 440.1R was conservatively evaluated in the tension-controlled section.

• 사료
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• s.51
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• pp.37-40
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• 2011