• Annals of Geriatric Medicine and Research
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• v.22 no.4
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• pp.159-166
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• 2018

The Korean Geriatrics Society was founded on October 3, 1968. Over the 50 years since then, the Society has incessantly strived to stay attuned to the aging society and to achieve an increasingly greater research impact in the field of gerontology and geriatric medicine. The Society has passed through periods of preparation for a leap forward, followed by rapid growth, expansion, and maturity. As a result, the Society has gained a firm foothold at home and abroad as a leading research society for both qualitative and quantitative achievements in geriatric medicine. At this juncture, with an ultra-aging society being just around the corner, we are celebrating its 50th anniversary and anticipating our second half-century with great enthusiasm about our mission and role as a leading geriatric research organization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.196-200
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• 2002

Lower field germination was observed in lipoxygenase- lacking soybean genotypes. This study was performed to understand seed-related traits after accelerated aging in response to planting date of soybeans. Two soybean cultivars, Jinpumkong (null lipoxygenase-2,3) and Jinpumkong 2 (lacking lipoxygenase-1, 2, 3) were evaluated for germination, and were compared with the cultivar, Taekwangkong containing lipoxygenase-1,2,3 isozymes. Greater seed coat cracking was shown in Jinpumkong and Jinpumkong 2 than Taekwangkong. Regardless of soybean genotypes, earlier planting resulted in greater seed coat cracking. After accelerated aging, seed fracturability and hardness of Jinpumkong and Jinpumkong 2 were lower than those of Taekwangkong. There was significant difference in germination percentage among soybean genotypes in response to planting date. Seeds obtained from late planting showed better germination ability. Accelerated aging resulted in lower germination percentages of Jinpumkong and Jinpumkong 2 than that of Taekwangkong, and showed higher electric conductivity in Jinpumkong and Jinpumkong 2 than Taekwangkong. After accelerated aging at 4$0^{\circ}C$ for thirty five days, germination percentages of Jinpumkong and Jinpumkong 2 were lower than that of Taekwangkong. Electric conductivity was increased continually as accelerated aging time became longer, and Jinpumkong and Jinpumkong 2 showed higher electric conductivity than Taekwangkong. Even though there were significant genotype differences in seed traits, further studies are needed to determine whether seed lipoxygenase ability is associated with germination ability.

• Journal of the Korean Ceramic Society
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• v.34 no.12
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• pp.1254-1260
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• 1997

Influence of applied electric field on the low temperature degradation of 3 mol% YaO3 stabilized tetragonal zirconia polycrystals(3Y-TZP) was investigated using X-ray diffractometry of specimens aged under the dc field of 1.1 kV/mm in silicone oil both of 12$0^{\circ}C$-21$0^{\circ}C$. After the aging, the tetragonal to monoclinic phase transformation was observed only on the specimen surface of 3Y-TZP faced to the anode. This indicated that the surface was overcrowded with oxygen ions as a result of diffusion of oxygen vacancies toward the cathode-sided surface. To elucidate an influence of the applying time of the electric field on the extent of the degradation of 3Y-TZP in air, specimens were aged fore 0-2 hours under the electric field in the oil bath of 12$0^{\circ}C$ and then subsequently aged for 3h at 22$0^{\circ}C$ in air. The longer the specimens were aged under the field, the more extensive the transformation to the monoclinic phase was on the specimen surface faced to the cathode, probably originated from a high diffusion rate of oxygen ions due to a steep oxygen vacancy concentration gradient.

• Journal of the Korean Ceramic Society
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• v.34 no.6
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• pp.620-628
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• 1997

The possibility of the existence of a field-induced micro-macrodomain switching was proposed and examined using 9 mol % PbZrO3-doped 0.6Pb(Ni1/3Nb2/3)O3-PbTiO3 (PNN-PT) systems having rhombohedral symmetry at room temperature. the thermally depoled (freshly prepard) specimens prepared from the rhombohedral side of the system exhibited a relaxor behavior for the whole range of temperature examined (for T

• Korean Journal of Health Education and Promotion
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• v.27 no.4
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• pp.73-81
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• 2010

Objectives: The purpose of this study was to evaluate the effects of 12 weeks walking exercise program participation on changes in aging-related hormones concentration in elderly men. Methods: 16 elderly men(above 65 years old) were participated in 12 weeks walking exercise program by group types(exercise group ; n=8 & control group ; n=8), and their aging-related hormones(GH, testosterone and melatonin) levels were assessed before program(0 week) and after program(12 weeks). Regularly walking exercise program(field walking exercise) performed for 12 weeks(3days/week, 60~70min/day, HRR 55~65%). All data were expressed as mean and standard deviation by using SPSS/$PC^+$(ver. 13.0) program, and to evaluate the differences before and after treatment by groups, data were analyzed by paired t-test(a${\leq}$.05) and 2-way ANOVA was performed to examine the differences between groups and within groups by variables. Results and Conclusion: The conclusions obtained from this study were as follows ; In growth hormone. testosterone and melatonin response after 12 weeks exercise was increased significantly in walking exercise group(p<.01; p<.001; p<.001). And in result of 2-way ANOVA analysis for group, exercise, group${\times}$exercise, as compared with the exercise, there is significant difference in all items. Interaction effect of between group and exercise is difference significantly on GH(F=5.915, p<.05), testosterone(F=15.117, p<.01) and melatonin(F=8.131. p<.01) in all groups. We observed a direct relationship(positive improvement) between the regular physical activity and aging-related hormones(growth hormone, testosterone and melatonin concentrations) in elderly men.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.502-508
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• 2020

This paper focuses on the electrical properties and stability against DC accelerated aging stress of ZnO-V₂O₅-MnO₂-Nb₂O₅-Bi₂O₃-Co₃O₄-Dy₂O₃ (ZVMNBCD) varistor ceramics sintered at 850 - 925 ℃. With the increase of sintering temperature, the average grain size increases from 4.4 to 11.8 mm, and the density of the sintered pellets decreases from 5.53 to 5.40 g/㎤ due to the volatility of V₂O₅, which has a low melting point. The breakdown field abruptly decreases from 8016 to 1,715 V/cm with the increase of the sintering temperature. The maximum non-ohmic coefficient (59) is obtained when the sample is sintered at 875 ℃. The samples sintered at below 900 ℃ exhibit a relatively low leakage current, less than 60 mA/㎠. The apparent dielectric constant increases due to the increase of the average grain size with the increase of the sintering temperature. The change tendency of dissipation factor at 1 kHz according to the sintering temperature coincides with the tendency of the leakage current. In terms of stability, the samples sintered at 900 ℃ exhibit both high non-ohmic coefficient (45) and excellent stability, 0.8% in 𝚫E_B/E_B and -0.7 % in 𝚫α/α after application of DC accelerated aging stress (0.85 E_B/85 ℃/24 h).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.172-178
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• 2017

Thermal property is one of the important characteristic in the field of energetic materials. As the energy material is released during decomposition, DSC(Differential Scanning Calorimetry) is frequently used for the thermal analysis. In case of the dynamic DSC measurements, thermal dynamic change like melting is prevented from the thermal property measurements. And due to the predicting kg scale, the conditions of the heat exchange with the environment significantly is changed. In this study, As the method to resolve the problem, we predict the thermal aging property using the AKTS thermokinetic program from DSC measurements which performed isothermal method. Predicting the thermal aging properties from ARC(Accelerating Rate Calorimetry) measurement, we compare two results.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.30-39
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• 2022

In this study, laboratory test, program analysis, and test construction in the field were performed to utilize Supplementary Cementitious Material (SCM) developed by recycled resources for slope reinforcement as slope improvement material for aging reservoir, and the results were analyzed. As results of the laboratory test, it was analyzed that the mixing ratio of SCM was appropriate by 9 %, and the coef. of permeability was decreased by about 10,000times, indicating a value close to that of the waterproof material applied in Korea. In addition, as a result of program analysis and test construction, it was analyzed that seepage did not occur in the part of reinforced using SCM and showed a higher safety facto r than domestic criteria. Therefore, since it shows sufficient waterproof and reinforcing effects in aging reservoir, it is judged that the slope improvement using SCM can replace the cement for repair and reinforcement method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05a
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• pp.1-4
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• 2000

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FD) has been required the complicated calculation method because of its complex repetition progressing. In this paper, it has been applied the new approach method to express FD for aging level calculation and investigated the relative degradation processing in outside EPDM insulator. As a result after testing, new proposed method has a capability to estimate in case of the field operated EPDM and accelerating test. Therefore, we find the differency of operated EPDM according to field condition.

• Journal of Engineering Education Research
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• v.18 no.1
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• pp.3-10
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• 2015

The purpose of the study was to investigate the policy implication and a usage model for aging workforces of research and development field in the era of working age population decline and the introduction of the retirement age legislation. In spite the importance of the use for aging workforces of R&D, previous studies have not been taken in terms of R&D workforces. In addition, the activated policies and services was implemented for the aged and retired people. Therefore, we suggested the usage model in four folds: 1) internal employment model, which is to hire and employ pre-retired active workforces by their retirement age, 2) internal and external linkage model, which is to make them to depart from their previous workplaces and move them to new workplaces where they can apply their knowledge and skills, 3) extending retirement age model, which is to expand their age limit and provide their job opportunities after they left their work, and 4) ouplacement model, which is to provide them with employment information and service as well as operate the educational programs before they leave the workpalce. Finally, we suggested the update of legislation and law for old workers, government supports for retiring workforces, and the conversation and compromise between R&D workforces and managers of workplaces.