• 한국노년학
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• v.39 no.3
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• pp.549-567
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• 2019

The present study examined whether the relation between relative handgrip strength and cognitive function varied by paid employment status and participation of social activities among Korean older adults. A total of 3,376 Korean adults aged 65 or older were drawn from the 2016 Korean Longitudinal Study of Ageing (KLoSA). Weighted hierarchical regression analyses were conducted to examine moderating effects of paid employment status and social activities on the relation between relative handgrip strength and cognitive function. After adjusting for covariates, results show that relative handgrip strength has a positive association with cognitive function. Both paid employment status and social activities have positive associations with cognitive function and moderate the relationship between relative handgrip strength and cognitive function. These significant moderating effects show that participating in paid employment and social activities buffer against the effect of lower handgrip strength on cognitive function. Findings from the present study highlight the significant role of active aging in older adults'cognitive function. Implications are discussed in a cultural context.

• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.112-122
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• 2023

To restore the ecological function of contaminated soil and maximize the ecological services provided by the soil, besides the toxicity orrisk caused by pollutants, the functional aspects of the soil ecosystem should be considered. In this study, a method for evaluating the health of cleaned soil was presented, and the applicability of the proposed evaluation method was examined by applying it to soil treated with washing and landfarming. Productivity, habitat, water retention capacity, nutrient cycling, carbon retention capacity, and buffering capacity were used as soil health evaluation indicators. The results showed that the soil health was not completely recovered after remediation, and even in the case of the washed soil, the health was lower than before remediation. On the other hand, there was no significant change in soil quality due to oil pollution, but soil health deteriorated. Unlike the slightly improved soil quality after landfarming treatment, soil health was not completely restored. Therefore, the results of this study indicate that it is desirable to consider both soil quality and health when evaluating the remediation effect. The soil health evaluation method proposed in this study can be usefully utilized for the sustainable use of cleaned soil and to promote ecosystem services.

• Korean Journal of Metals and Materials
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• v.49 no.10
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• pp.811-817
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• 2011

In this study, we have investigated the role of a metal oxide hole injection layer (HIL) between an Indium Tin Oxide (ITO) electrode and an organic hole transporting layer (HTL) in organic light emitting diodes (OLEDs). Nickel Oxide films were deposited at different deposition times of 0 to 60 seconds, thus leading to a thickness from 0 to 15 nm on ITO/glass substrates. To study the influence of NiO film thickness on the properties of OLEDs, the relationships between NiO/ITO morphology and surface properties have been studied by UV-visible spectroscopy measurements and AFM microscopy. The dependences of the I-V-L properties on the thickness of the NiO layers were examined. Comparing these with devices without an NiO buffer layer, turn-on voltage and luminance have been obviously improved by using the NiO buffer layer with a thickness smaller than 10 nm in OLEDs. Moreover, the efficiency of the device ITO/NiO (< 5 nm)/NPB/$Alq_3$/ LiF/Al has increased two times at the same operation voltage (8V). Insertion of a thin NiO layer between the ITO and HTL enhances the hole injection, which can increase the device efficiency and decrease the turn-on voltage, while also decreasing the interface roughness.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.248-255
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• 2020

In this study, we analyze the current state of domestic food waste (FW) recycling and propose a management plan for greenhouse gas (GHG) emissions. First, the composting potential of the GW demonstrates considerable promise. In particular, the GW (phytoplankton, periphyton, macrophyte, etc.) as a third-generation biomass shows strong performance as a functional additive that mitigates the disadvantages associated with composting FW and improves the quality of the final composted product. Alternatively, the final product (e.g., soil ameliorant) can be used to produce bio-filters that are effective pollutant buffers, with high applicability for green infrastructure. The proposed ecological approaches create new opportunities for FW as a resource for the reduction of GHG emissions, and are expected to contribute to the establishment of effective net-zero carbon systems in the future.

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1507-1514
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• 2018

The purpose of this study was to propose a functional improvement solution of integrated control board for safe driving of Smart electric wheelchair for a single person. In the case of existing electric wheelchair products in Korea and elsewhere, safety-related functions or devices are not included in many cases. Therefore, the incidence of electric wheelchair-related accidents is continuously increasing in the current situation in which the elderly and the disabled people have been continuously increased. However, currently only high and middle-priced products are equipped with basic safety devices in electric wheelchairs, so low-priced products require safety related functions. Therefore, sensing obstacles that the user can not recognize while moving an electric wheelchair and detecting automatically the terrain change to control the motor by developing a smart control platform. This provides an integrated control board that can be applied to various electric wheelchairs for more stable driving.

• The tire
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• s.123
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• pp.39-45
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• 1986

국제천연고무 가격의 하락세가 최근 가속화 되고 있다. 천연고무 가격은 80년대들어 70년대의 상승세가 하락세로 반전하여 작년말 10년만의 최저시세인 kg당 150싱가포르센트 까지 하락한 바 있다. 이와같이 천연고무가격이 떨어지고 있는것은 천연고무의 대체품인 합성고무의 개발과 사용이 급속히 확산되어 천연고무의 소비증가가 둔화되고 있을 뿐 아니라, 천연고무의 생산이 집중되어 있는 인도네시아를 포함한 동남아시아 각국은 외화를 획득하고 역내에서 시장의 주도권을 잡기 위하여 생산과 수출을 적극적으로 증가시키고 있기 때문이다. 또한 이와같은 천연고무 가격의 하락은 국제 천연고무기구와 완충재고를 상한선인 40만톤까지 증대시켜, 가격유지기능을 상실하게 만들고 있다. 앞으로 국제천연고무 가격은 특히 유가의 폭락으로 합성고무의 가격이 떨어지고 또 막대한 재고가 쉽사리 소진되기 어렵다는 점 등으로 미루어 보아 장기적인 약세기조가 지속될 것으로 예상된다.

• Computational Structural Engineering
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• v.11 no.4
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• pp.331-340
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• 1998

본 연구에서는 이동제한장치가 있는 연속교의 지진응답특성을 고찰하였다. 일점고정연속교에 있어서 이동제한장치는 교각이 탄성거동을 하는 경우 교축방법 수평력 분산기능이 있으며 교각하부에 소성힌지가 발생하거나 내진분리베어링이 있는 경우에는 최대변위 및 비탄성거동에 따른 잔류변위제한에 매우 효과적이다. 상부구조와 이동제한장치의 충돌시 발생하는 충격력은 완충재의 사용으로 상당히 감소시킬 수 있다. 이동제한장치의 설치위치 및 이격거리는 이동제한장치가 설치될 하부구조의 강성 및 강도와 온도변화, 급제동력, 작은 지진발생시 충돌여부, 신축이음장치유간 등을 고려하여 결정되어야 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.169-180
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• 2016

The spaces of port and urban in a Port City have different space characteristics substantially, but those are required to be developed interdependently. Degradation and loss of the sense of place in the existing spaces caused by decline of natural function have an adverse effect on the revival of local economy as well as make worse image of the entire city. In some developed countries, therefore, many researches on the port spaces lagging behind the times due to changes of the characteristics and function of port spaces have been conducted continuously for a long time. This study aims at seeking a device how the domestic hinterland could be utilized as efficient spaces having the characteristics of outskirts space and port city interface through the application of characteristics of the interface space of port city, capable of playing a role as buffer zone between the port space and the city space.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.4
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• pp.419-426
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• 2017

In implant restorations, it is difficult for the patient to percept any symptoms. In addition, they are absent of shock absorbers, which can lead to mechanical failure if stress distribution is not considered. Since maxillary anterior multiple-implant restorations play a significant role in guiding the functional movement of the mandible by distributing lateral force, it is crucial to form appropriate occlusion. The use of the T-scan system is more advantageous in assessing 'dynamic occlusion', such as the change of occlusion over time, the amount of tooth contact during functional movement, and assessing the occlusion in the less-visible posterior teeth. The case is reported as it has satisfactory results in harmonious anterior guidance of a maxillary anterior multiple-implant restoration using T-scan analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.198-203
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• 2019

An adhesive wireless bookbinding machine was designed with optimal motor control and automatic cover insertion for bookbinding. The noise level was improved by modifying the thrust of the machine and changing from a compressor method to an AC induction motor control method. The automatic cover insertion function was added to improve the task speed. Motor and decelerator damage can be caused by sudden braking and acceleration of the motor rotation (clockwise and counter-clockwise), so a buffer-type locational control system was developed to secure stable movement and durability. The complicated internal design was also simplified, and the volume and weight were decreased. The results show that the noise was decreased by 57% from 135 dB to 71.7 dB, and the task speed was decreased by 57% from 18 s to 9.58 s. The automatic cover insertion was designed to supply a maximum of 130 sheets per supply.