• Nuclear Engineering and Technology
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• v.5 no.1
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• pp.55-64
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• 1973

The effect of compression in the strain ageing of Ferrovac E iron has been examined with compressive testing following the prestrain in compression. Both prestraining and testing were preformed at room temperature with the strain rate of 1.9$\times$10$^{-4}$ se $c^{-1}$ and that of 0.95$\times$10$^{-4}$ se $c^{-1}$ , respectively. Ageing was carried out at several temperatures below 8$0^{\circ}C$ using thermostatically controlled oil baths with a temperature control within$\pm$1$^{\circ}C$. It was found that the rate of strain ageing obeyed the $t^{2}$3/ law up to about five hours ageing at 6$0^{\circ}C$. The rate was slower than theses reported in case of the tensile prestrained iron. Activation energy for strain ageing has been estimated as 21.5 Kcal/mole at tile first stage of the aging process. At the second stage of ageing where the $t^{2}$3/ law is still valid, however, the activation energy was somewhat decreased. The activation energy at the first stage of ageing was about 10% larger than published results on the tensile-prestraining. This difference between the activation energies is explained in terms of the residual stress field in lattice.

• 한국노년학
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• v.37 no.1
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• pp.55-82
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• 2017

The purpose of this research is to provide implications for the development of age-friendly industry of Korea by analyzing the age-friendly industry activation policy suggested by the Presidential Committee on Ageing Society and Population Policy in response to the population ageing problems. Policy and theoretical implications are derived from an analysis of age-friendly industry activation policy as directly related to the improvement of the three major problems (i.e. health, economy, and loneliness) of Korean older people. This analysis focuses on its specific content, common and core logic, and the validity of the logic. The results show that: 1)the first Plan for Ageing Society and Population suggests a policy for improving poverty, 2)the second Plan for Ageing Society and Population suggests a policy for improving health, and 3)the third Plan for Ageing Society and Population suggests a policy for improving health and loneliness. All policies not only are commonly based on the logically limited concepts of successful ageing and active ageing, but also are characterized by narrow realm, insufficient content, and fragmented policy. The results result in the following policy implications: 1)the age-friendly industry activation policy should be developed with continuity, sufficiency, and diversity, 2)lessons from the limitation related with the de-contextualisation of successful ageing and its elective affinity with consumer capitalism, 3)lessons from the prevention-oriented perspective of active ageing, and 4)lessons from the social characteristics of (non-)psychological resources, limitation of the reablement related with social investment state. The analyses also provide a theoretical implication that a different perspective on the social construct of ageing is needed beyond the dichotomy of ageing based on modelling ageing. Lastly, the paper suggests not only the limitation of the research but also the preferred follow-up studies regarding age-friendly industry activation policy.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.6
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• pp.311-319
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• 2019

The number of aged bridges is increasing so that bridges over 30 years old account for about 11% of all bridges. Consequently, the development of a seismic performance evaluation method that considers the effects of ageing is essential for a seismic retrofitting process for improvement of the seismic safety of existing old bridges. Assessment of the damage situation of bridges after the recent earthquakes in Korea has been limited to the bearings, anchor, and concrete mortar on piers. The purpose of this study is to evaluate the seismic responses of PSC box girder bridges by considering the ageing effect of rubber bearings (RBs) and lead-rubber bearings (LRBs). The modification factor proposed by AASHTO is used to take into account the ageing effect in the bearings. PSC box girder bridges with RBs and LRBs were 3D modeled and analyzed with the OpenSEES program. In order to evaluate the ageing effect of RBs and LRBs, 40 near fault and 40 far field records were used as the input earthquakes. When considering the effect of ageing, the displacement responses and shear forces of bridge bearings (RBs and LRBs) were found to increase mostly under the analytical conditions. It was shown that the effect of ageing is greater in the case of RBs than in the case of LRBs.

• Health Policy and Management
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• v.28 no.4
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• pp.378-391
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• 2018

Background: People who were born in different years, that is, different birth cohorts, grow in varying socio-historical and dynamic contexts, which result in differences in social dispositions and physical abilities. Methods: This study used age-period-cohort analysis method to establish explanatory models on healthcare expenditure in Korea reflecting birth cohort factor using intrinsic estimator. Based on these models, we tried to investigate the effects of ageing population on future healthcare expenditure through simulation by scenarios. Results: Coefficient of cohort effect was not as high as that of age effect, but greater than that of period effect. The cohort effect can be interpreted to show 'healthy ageing' phenomenon. Healthy ageing effect shows annual average decrease of -1.74% to 1.57% in healthcare expenditure. Controlling age, period, and birth cohort effects, pure demographic effect of population ageing due to increase in life expectancy shows annual average increase of 1.61%-1.80% in healthcare expenditure. Conclusion: First, since the influence of population factor itself on healthcare expenditure increase is not as big as expected. Second, 'healthy ageing effect' suggests that there is a need of paradigm shift to prevention centered-healthcare services. Third, forecasting of health expenditure needs to reflect social change factors by considering birth cohort effect.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.243-246
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• 2001

At atmosphere photoluminescence(PL) of porous silicon(PSi) decreases and peak wave number of PL is shifted to blue region. When PS is used light detector, the ageing effects are negative phenomena. For controling ageing effects, this paper uses Polymers.

• 전기의세계
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• v.22 no.2
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• pp.23-27
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• 1973

An initial starting voltage, ignition time, glow current and blink of the flow starter are changed rapidly in initial using. therefore an ageing is required to stabilize the initial characteristics. According to the experiments, it is proved that the ageing time for the starting voltage and glow current takes 3 minutes and 5 minutes for ignition time and blink.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1664-1666
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• 1999

In order to study the mechanical properties of high nitoren steel with ageing time, hardness, tensile stress several basic properties of Fe-Mn-Cr-Ni-N steel have been studied. With increasing partial pressure of nitrogen and ageing time to 10h, hardness and tensile stress are increased, but decreased beyond 10h because of over ageing. It is considered that the main factor related with mechnical properties is carbide precipitate, $M_7C_3$ which is precipitated with ageing time in matrix and optimum ageing time is 10h in $60^{\circ}C$.

• Transactions on Electrical and Electronic Materials
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• v.7 no.5
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• pp.230-234
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• 2006

One of the methods currently being investigated as a possible non-intrusive diagnostic tool for condition monitoring of power transformer and cable is the recovery voltage measurement, which will be improving the ability to detect the content of water concentration and the ageing process in the insulation system and may thus be an indicator of insulation quality and its ageing status. The polarization phenomenon was studied using RVM with oil-paper samples. In order to interpret its mechanism, the Extended Debye model was introduced. With different circuit parameters, various simulation results were gotten. Furthermore, with the test samples of different ageing condition, measurements are accomplished in the lab. On the basis of this experiment as well as theoretical analysis, correlations between polarizations and ageing were analyzed.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.4
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• pp.233-239
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• 1992

A study of the precipitation process of Al-Li binary alloy at low ageing temperature has been carried by electrical resistivity measurement. Two types of G.P.zones were formed during ageing at low temperature. G.P. (1) zone and G.P. (2) zone have been formed primarily at ageing temperature below $60^{\circ}C$ and at ageing temperature range of $80^{\circ}C$ to $100^{\circ}C$, respectively. Therefore the precipitation process of Al-Li binary alloy was as follows; G.P.(1) zone ${\rightarrow}$ G.P.(2) zone ${\rightarrow}{\delta}^{\prime}{\rightarrow}{\delta}$ G.P. (1) zone might be affected by excess vacancies, but G.P. (2) zone might be affected by secondary defects. clusters and Li-vacancy pairs. The activation energy for formation of G.P. (2) zone is 0.87eV. It is lower than that of Al-Cu alloy.

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.44-47
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• 1994

The ageing behavior of Cu-bearing HSLA steels was studied by using Differential scanning calorimetry(DSC), Transmission electron microscopy and hardness tester. Two heat evolution peaks were observed during DSC scans over the temperature range of 25～590$^{\circ}C$ at a heating rate of 5$^{\circ}C$/min. The peaks appeared in low (241∼319$^{\circ}C$ : HSLA-A, 224∼310$^{\circ}C$ : HSLA-B) and high temperature (514∼590$^{\circ}C$ : HSLA-A, 451∼558$^{\circ}C$ : HSLA-B) are attributed to the formation of coherent Cu-clusters and noncoherent $\varepsilon$-Cu phase, respectively. It was confirmed that as ageing proceeds, the coherent bcc Cu-clusters transform to noncoherent fcc $\varepsilon$-Cu phase. In the case of the ageing to peak hardness at 300$^{\circ}C$ and 400$^{\circ}C$, the coherent Cu-clusters contributed to the hardening. As ageing time and temperature increase over peak hardness, noncoherent $\varepsilon$-Cu are formed and hardness decreases.