• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1020-1025
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• 1998

Irradiation-induced changes in mechanical properties and magnetic parameters were measured and compared to explore possible correlations for Mn-Mo-Ni low alloy steel surveillance specimens which were irradiated to a neutron fluence of $2.3\times10^{19}n/cm^2$(E>1.0MeV) in a typical pressurized water reactor environment at about $288^{\circ}C$. For mechanical property parameters, microvickers hardness, tensile and Charpy impact test were performed and Barkhausen noise amplitude, coercivity, remanence, maximum induction were measured for magnetic parameters. respectively. Results of mechanical property measurements showed an increase in yield and tensile strength, microvickers hardness. 41J indexed $RT_{NDT}$ and a decrease in upper shelf energy irrespective of base and weld metals. However, in the case of tensile properties, the changes in weld metal were negligible compared to the base metal. In the case of magnetic measurements, it is found that magnetic remanence, BN amplitude. BN energy have dropped significantly but coercivity(H,) has increased rapidly after irradiation. In this study. the measurements conducted on surveillance specimens of Mn-Mo-Ni low alloy steel showed that there were strong correlations between mechanical properties and magnetic properties.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.447-453
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• 2018

Since 1960, Korea the town center was developed intensively due to rapid industrial development. As a result of the development, the population was concentrated in urban areas and the green area was decreased. Due to the decrease of the green area, the circulation system of the rainwater was changed, hence the rainwater was not introduced into the groundwater., On the other hand, the water on the surface of the road was changed into the water for flowing to the river and evaporation. The changes in the water flow cause many problems, and the depletion of the groundwater does not create an environment in which microorganisms and plants can live. in Korea, permeable pavement construction is increased to solve these problems, but existing pavement blocks have many problems. The pores of the permeable block are clogged due to the accumulation of dust or whitening phenomenon, and the permeability is lost. In this study, the solution of the problems of existing permeable block were suggested by using polymer and artificial permeable pipe, and strength, permeability and service life are increased, The relationship between the substitution rate of the polymer and the mixing ratio of the artificial permeable pipe was analyzed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.430-435
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• 2012

This study was carried out to investigate the rheological effects of black garlic extracts on the bread dough. 0, 5, 10 and 15% of black garlic extracts were added in the bread flour. Falling number, RVA (Rapid visco analyser), farinograph and alveograph were analyzed. Falling number was lowered by increasing the amount of the extract added in the wheat flour. The pasting characteristics of the dough by RVA, value of pasting temperature, peak viscosity, holding strength, final viscosity, break down and set back were increased compared to the control. In the Farinograph analysis, the consistency and the water absorption ratio were elevated with the increase of the extract added. However, the rapid decrease of stability and the time to breakdown values were observed by increasing the extract addition amount compared to the control. However the mixing tolerance index (MTI) was rapidly increased as the amount of the extract addition was increased, and the highest farinogram quality number was observed in the control. Through the alveograph analysis, $P_{max}$ value was found to show the highest value in the control, while the L and G values were higher but W values was lowered in the dough with added 15% black garlic extract. As a result of the analysis, there was no significant bad effect until 5% of black garlic extracts was added to the bread dough.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5514-5521
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• 2013

This study is an experiment to look into recovering process after maximum anaerobic exercise of career wrestlers and their basic fitness. First, group time results in anaerobic power test did not show meaningful differences between groups in PP, MP, LP field. Second, blood glucose showed meaningful difference in 5-year wrestlers group according to time-wise result (p<.001). Third, time-wise results in blood lactic acid concentration showed meaningful difference all in 5-year, 10-year and 15-year career wrestlers group (p<.001). Fourth, side step and general reaction did not show meaningful differences in all the 3 groups. In conclusion, increase or decrease was seen from and also significant differences were seen from the change of anaerobic power, glucose, lactic acid, concentration, basic physical strength reaction which have influence over athletic performance of players after anaerobic exercise. It was found that 5-year career players group was good at variables of power test and glucose. Reason why recovery capability in connection with degree of fatigue was poor in 15-year career players group seemed to have correlation between career and age.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.589-597
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• 2009

High Performance Fiber-reinforced Cement Composite (HPFRCC) shows the multiple crack and damage tolerance capacity due to the interfacial bonding of the fibers to the cement matrix. For practical application, it is needed to investigate the fractural behavior of HPFRCC and understand the micro-mechanism of cement matrix with reinforcing fiber. This study is devoted to the investigation of the AE signals in HPFRCC under monotonic and cyclic uniaxial compressive loading, and total four series were tested. The major experimental parameters include the type and volume fraction of fiber (PE, PVA, SC), the hybrid type and loading pattern. The test results showed that the damage progress by compressive behavior of the HPFRCC is a characteristic for the hybrid fiber type and volume fraction. It is found from acoustic emission (AE) parameter value, that the second and third compressive load cycles resulted in successive decrease of the amplitude as compared with the first compressive load cycle. Also, the AE Kaiser effect existed in HPFRCC specimens up to 80% of its ultimate strength. These observations suggested that the AE Kaiser effect has good potential to be used as a new tool to monitor the loading history of HPFRCC.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.260-272
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• 2010

This study examined how the participation rates contribute to subjects' outcomes after a nutrition education (once/week) and exercise (3 times/week) intervention program for 12 weeks in 44 obese female subjects. The subjects were divided into two groups: high-participator (HP) or low-participator (LP) groups according to their participation levels based on the median visit value (30 visits out of a total of 48 visits). Daily nutrient intakes assessed by a 24-hour recall, body composition, blood lipid profiles and physical fitness were measured at baseline and after 12 weeks. After the intervention, weight, BMI, percent body fat, and the waist-hip ratio were significantly decreased in the HP group. In addition, the HP group had a greater rates of changes in weight (HP group: -6.6% and LP group: -3.1%, p < 0.01), BMI (-7.0% and -3.2%, p < 0.01), percent body fat (-7.8% and -4.2%, p < 0.05), and waist-hip ratio (-3.1% and -0.4%, p < 0.01) compared to the LP group. Energy-adjusted protein, fiber, potassium, vitamin $B_1$, vitamin $B_6$, and vitamin C were significantly increased in the HP group. The HP group showed a significant increase in HDLcholesterol and a decrease in blood pressure, total cholesterol, LDL-cholesterol, triglycerides, and atherogenic index (AI). While the muscle endurance, muscle strength, power, agility and flexibility were significantly increased in the HP group, agility and balance were improved in the LP group. In addition, dietary behavior score was significantly increased and stress score decreased in the HP group compared to the LP group. High participation rates were correlated with the improvement of the nutrient density (protein, fiber, potassium, Vitamin $B_1$, Vitamin $B_2$, Vitamin $B_6$ and folate), anthropometric parameters (body weight, BMI and percent body fat), serum lipid profiles (HDL-cholesterol, Triglyceride, and AI) and physical fitness (muscle endurance) adjusted for age, menopausal status, alcohol drinking, nutritional supplement use and baseline BMI. Our results suggest that high participation in nutrition education and exercise program was effective not only for weight reduction but also for the improvement of physical fitness in obese women.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.474-481
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• 2019

Korea entered the aged society in 2018 with the elderly population accounting for 14.4% of the total population, and it is expected to enter the super-aged society in 2026. In particular, it is predicted that by 2050, the elderly population will be 38% of the total population, making it one of the countries with the highest number of elderly people in the world. The increase in the elderly population is naturally leading to an increase in the number of traffic accidents among elderly drivers, in 2017, there were 26,713 elderly driver accidents over 65 years of age, with 848 people dying and 38,627 injured. Compared with 2011, the number of accidents and injuries has doubled and the number of deaths has increased 1.4 times. This study determined that the main factors of the increase in traffic accidents were the characteristics of elderly drivers, such as a decrease in visual/hearing ability, cognitive and information processing ability, and muscle strength. Therefore, it raised the necessity of autonomous vehicle(level 2) for elderly driver who can minimize the burden of driving and aimed to study the function of autonomous vehicle for elderly driver who is not familiar with new technology. Based on this, four functions of autonomous vehicles for elderly drivers were derived, such as providing clear information according to the road environment, considering physical characteristics of drivers, simplifying interface, and reinforcing in-vehicle safety devices.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.23-30
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• 2006

Emulsified Asphalt Mixture(EAM) is more environmentally-friendly and cost-effective than typical Hot Mix Asphalt (HMA) because EAM does not produce carcinogenic substances, e.g., naphtha, kerosene, during the both of manufacturing and roadway construction process. Also, it does not require heating the aggregates and asphalt binder. However, EAM has some disadvantages. Generally EAM has a less load bearing capacity and more moisture susceptibility than conventional HMA. The study evaluated a Fiber modified EAM (FEAM) to increase load bearing capacity and to decrease moisture susceptibility of EAM. Modified Marshall mix design was developed to find Optimum Emulsion Contents (OEC), Optimum Water Contents (OWC), and Optimum Fiber Contents (OFC). A series of test were performed on the fabricated specimen with OBC, OWC, and OFC. Tests include Marshall Stability, Indirect Tensile Strength, and Resilient modulus test. Comparison analyses were performed among EAM, Fiber modified EAM (FEAM), and typical HMA to verify the applicability of EAM and FEAM in the field. Test results indicated that both of EAM and FEAM have an enough capability to resist medium traffic volume based on the Marshall mix design criteria. Also the study found that fiber modification is effective to increase the load bearing capacity and moisture damage resistance of EAM.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.91-97
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• 2015

Papermakers wish to increase the filler content of printing and writing grades because it allows saving in production cost through fiber replacement and improving the formation, and optical and printing properties of the paper. However, high filler loading in the base paper has negative side effects. It reduces the mechanical properties of paper and induces cracking at the fold after coating process. Fold cracking is one of the most frequent quality complaints for magazines, high quality books, etc. Two approaches were examined as methods to reduce fold cracking. One approach was to use preflocculated fillers, which was expected to reduce the fold cracking because it would decrease the interfiber bonding. The other approach was to use a new coating binder that gives greater binding power and thereby provides an opportunity of reducing the fold cracking of coated paper. When filler preflocculation was employed in producing the base paper, fold cracking becomes more severe than conventional filler loading condition. On the other hand, use of nano sized binder in coating improved the tensile properties of the coating layer and thereby decreased the crack area. It was shown that tensile properties of coating layer played an important role in fold cracking of coating.

• Journal of the Korean Vacuum Society
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• v.17 no.3
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• pp.175-182
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• 2008

This study is concerned with the evaluation of the corrosion resistance of coated semiconductor equipment parts with various processes. To select the appropriate basis for evaluation, replacement parts were observed during the semiconductor manufacturing process. This study also ran a dry corrosion test using $Al_2O_3$, which is mostly used as a coating material. This test quantitatively measured the efficiency of coated parts. Surface morphology, leakage current and breakdown voltage were also evaluated. This study showed that a dry corrosion process led to the drop of electrical properties, for example, the leakage current increase and the dielectric strength decrease. The surface morphology test displayed that surface damage is largely dependent on the exposure time to corrosive environments. By using the values that changed during the corrosion process, it may be possible to contrive a method to evaluate the efficiency of coated parts with various processes.