• Smart Structures and Systems
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• v.24 no.1
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• pp.111-125
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• 2019

Metallic shape memory alloys present fascinating physical properties such as their super-elastic behavior in austenite phase, which can be exploited for providing a structure with both a self-centering capability and an increased ductility. More or less accurate numerical models have been introduced to model their behavior along the last 25 years. This is the reason for which the literature is rich of suggestions/proposals on how to implement this material in devices for passive and semi-active control. Nevertheless, the thermo-mechanical coupling characterizing the first-order martensite phase transformation process results in several macroscopic features affecting the alloy performance. In particular, the effects of day-night and winter-summer temperature excursions require special attention. This aspect might imply that the deployment of some devices should be restricted to indoor solutions. A further aspect is the dependence of the behavior from the geometry one adopts. Two fundamental lacks of symmetry should also be carefully considered when implementing a SMA-based application: the behavior in tension is different from that in compression, and the heating is easy and fast whereas the cooling is not. This manuscript focuses on the passive devices recently proposed in the literature for civil engineering applications. Based on the challenges above identified, their actual feasibility is investigated in detail and their long term performance is discussed with reference to their fatigue life. A few available semi-active solutions are also considered.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.2
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• pp.42-47
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• 2005

Micro duplex stainless steel is used to denote a fine scale two-phase micro structure consisting austenite and firrite. The development of this structure was done by proper thermo-mechanical processing. The objective of present investigation is to study creep characteristics of this alloy. Since we have little design data about the W behaviors of the alloy. An apparatus has been designed and built fir conducting creep tests under constant load conditions. A series of creep tests on them have been performed to get the basic design data and life prediction of micro duplex stainless steel products and we have gotten the 1311owing results. First the stress exponents decrease as the test temperatures increase. Secondly, the creep activation energy Gradually decreases as the stresses become higher. Thirdly, the constant of Larson-Miller Parameters on this alloy is estimated as about 5. Last, the fiactographs at the creep rupture show both the ductile and brittle fracture modes according to the creep conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.63-63
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• 2001

As a new approach to substitute for a hard alloy of stellite 6B containing Co which is radioactive in nuclear system, a hard-phase coating of CrN will be applicable to protect 12Cr steel from erosion at leading edge on steam turbine blade. The CrN coating was prepared by arc ion plating on 12 Cr steel and was undertaken in liquid impact test at the velocity of 35Om/sec, which simulate the environment in the last stage of blade. The erosion resistance of coating was evaluated by optical observation on damaged surface. The threshold number of impact was closely related with surface hardness. And thus, it was confirmed that surface hardening improves the life time of steam turbine blade.

• Journal of Animal Science and Technology
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• v.52 no.3
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• pp.213-220
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• 2010

This study was executed to investigate the effects of drinking deep sea water treated by reverse osmosis process (RO-DSW) on growth performance, nutrient utilizability, relative weight of lymphoid organs and the concentration of serum immunoglobulin G (IgG) in broiler chickens. A total of 200 one day old broiler chickens (Ross 308) were equally and randomly distributed into 10 ground floor pens (20 chicks per pen, 5 pens per treatment) bedded with rice-husks. The broilers were offered either fresh tap water (Control) or RO-DSW for 28 days (from d 6 to d 33) as the drinking water. The same basal phase 1 diet for first 2 weeks and phase 2 diet for last 2 weeks were offered ad libitum to the birds. The RO-DSW was prepared by diluting 1:20 ratio with deionized water before offering to chickens. The diet for control birds was supplemented with 0.21 % of food-grade salt to satisfy salt need of the birds. Broiler feeding study resulted that there were no differences in amount of water consumption, mortality and FCR between RO-DSW and control chickens. However, feed intake and body weight gain were increased (p<0.05) by RO-DSW drinking. There was no (p>0.05) difference in nutrients utilizability between RO-DSW and fresh water drinking. There were no (p>0.05) differences in the immune response between the control and treatment group. The serum IgG levels were 3.01 vs 2.87 mg/ml and the relative weights of spleen, thymus and bursa of Fabricius were 0.23, 0.18 and 0.20 vs. 0.20, 0.17 and 0.14 for RO-DSW vs. control birds, respectively. The immune responses were tended to be improved by RO-DSW drinking. This study showed an improvement in weight gain and feed intake that could be induced by RO-DSW drinking, although it is difficult to explain the reasons of the improvement at this moment. This study implied that RO-DSW could be successfully used as drinking water to broiler chickens.

• Korean Journal of Social Welfare
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• v.42
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• pp.169-198
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• 2000

This paper attempts to analyze the early retirement in the OECD countries and discuss implication of that in the old age policy in Korea. The increase of the early retirement in the almost all OECD countries is a common fact. Especially the rate of early retirement rapidly increased in the 1980s, mostly reflecting the high rate of unemployment and states' policies to reduce it. However, it varies across countries: the unemployment compensation pathway in France, the mixture of social assistance and private insurance in England, VUT in Netherland, the privatization of the early retirement in the U. S., and partial retirement and labor market policy in Sweden. The early retirement in the advanced countries contributes to de-institutionalization and de-standardization in life course model. It resulted in the erosion of the ordinary conception that the retirement was the beginning of the old age. And the last phase of life course became blurred. With respect to the problem of the early retirement, there is a big difference between Korea and the OECD countries. Above all, the retirement age is 55 years in many companies and the public pension is not universalized in Korea. Accordingly the policy for income security of the old age in Korea should be connected with social security policy such as the gradual extension of the retirement age and the expansion of the public pension and labor market policy such as job training for the old age, transformation of the seniority wage system etc.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.4
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• pp.279-284
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• 2021

The dung beetle, Gymnopleurus mopsus (Coleoptera: Scarabaeidae), is one of endangered species in South Korea. It was last recorded in 1971. To restore this species, we introduced G. mopsus populations from eastern and southern regions of Mongolia in July 2019 and August 2019, respectively. One of the main tasks for the restoration of endangered insects is to develop breeding techniques to eventually incorporate these insects into the restoration system. In a series of laboratory experiments, we investigated effects of short-term hibernation periods on life-history traits of G. mopsus. Adult G. mopsus that had hibernated for 30, 60, and 90 days had lower survival rates than adults that had hibernated for 120 days. We also compared developmental time of these four experimental groups and found a significant difference in the egg - phase. However, the duration of hibernation did not affect the fecundity, brood-ball size, or body size of F1 adults. Follow-up studies are currently being conducted to further investigate the effect of a short-term hibernation period on population growth of G. mopsus under laboratory conditions.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.61-67
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• 2022

The effects of dietary exogenous hydrophilic emulsifiers on the growth, nutrient digestibility, and carcass characteristics of broilers were evaluated. A total of 200 one-day-old broilers (Ross 308) were allotted to one of four treatment groups in a randomized complete block design in five replicates with 10 birds per pen during a 5-week growth experimental period. Birds were fed a corn-soybean meal-based diet with or without the addition of 0.025, 0.050, or 0.075% exogenous hydrophilic emulsifiers. The diets contained 3,025 and 3,075 metabolizable energy/kg for Phases 1 and 2, respectively. For each phase and the overall experimental period, body weight gain (linear, P<0.05) and feed conversion ratio (linear, P<0.05) improved in proportion to the dietary exogenous hydrophilic emulsifier level, while the average daily feed intake was not affected by dietary treatment. Improvement in growth performance by dietary treatments was observed during the last two weeks rather than the first three weeks of the growth phase. In carcass traits, abdominal fat content increased as dietary exogenous hydrophilic emulsifier level increased (linear, P<0.05), whereas dietary emulsifier level did not affect the relative weight of the liver, breast, and leg muscles. In conclusion, addition of dietary exogenous hydrophilic emulsifiers from 0 to 0.075% in broiler diets improved the growth rate and feed efficiency of broilers without any deleterious effects on nutrient digestibility, although a corn-soybean meal-based diet had less energy content (3,025 and 3,075 metabolizable energy/kg) for 0-3 weeks and 3-5 weeks, respectively.

• Journal of Hospice and Palliative Care
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• v.10 no.2
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• pp.67-73
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• 2007

To make ones life meaningful is one of human's most valuable goal. Nevertheless, for cancer patients who are in the last phase of their lives obtaining this goal may be threatened by physical, psychological, and social difficulties. Music therapy ran be utilized to effectively fill in these physical, psychological, and social needs. In the form of a creative art, music therapy can be effective in easing the pain and tension as well as assisting the patient to discover meanings of life through psychological comfort. Further, music is itself a verbal/non-verbal communication tool and thus connects the patients with their families with understanding and sympathy. This study aims to examine the need and role of music therapy in hospice.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.1-10
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• 2009

Energy efficient operations are essential to increase the life time of wireless sensor network. A cluster-based protocol is the most common approach to preserve energy during a data aggregation. This paper deals with an energy awareness and autonomous clustering method based on time delay. This method consists of three stages. In the first phase, Candidate Cluster Headers(CCHs) are selected based on a time delay which reflects the remaining energy of a node, with considering coverage efficiency of a cluster. Then, time delay is again applied to declare Cluster Headers(CHs) out of the CCHs. In the last phase, the issue on an orphan node which is not included into a cluster is resolved. The simulation results show that the proposed method increases the life time of the network around triple times longer than LEACH(Low Energy Adaptive Cluster Hierarchy). Moreover, the cluster header frequency is less diverse, and the energy on cluster heads is less spent.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4853-4862
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• 2012

In Modern Cities, The 'Cultural spaces or facilities' are the core of the urban activity. And it is the field of urban life which can improve the quality of life and change the human's life style. Also in Contemporary society, Cultural spaces are required to express the social and psychological activity of the city life and the diversity and function of human beings. But most of them are located in the Metropolitan area. In these days, the needs of cultural spaces and facilities in 'Medium sized-cities' are growing. And many development plans are working in practice in that cities to accede to these requirements of social, human and current of the times. They include the exhibition spaces which perform function of the field of art and culture, that have powerful and infinite potentiality of the social development. At this Point, this study suggest that 'Optimum level' of exhibition spaces as Museum and Art-gallery in Medium sized-cities. To achieve this study, two phases are proceeded as follows. First, Check the social needs of it based on theoretical inquiry of Exhibition space. Second, Focused on Medium sized-cities, through a comparison between 12 Domestic cities and 4 Japan's cities. A population of their cities is from 500,000 to 1,000,000. We can get a data for Optimum level of Exhibition space. And last, Suggest the strategies of the location and planning of Exhibition space based on Second phase.