• Nuclear Engineering and Technology
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• 제32권3호
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• pp.274-282
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• 2000

The simulation of water balance was conducted for suggested four alternative multi-layer cover design of near-surface radioactive waste disposal facility under domestic climate condition. The analysis was also conducted for the most favorable one out of four alternative cover design under conservative scenarios. Until 100 years after closure of disposal vault, the infiltration flux for the most favorable cover design was negligible even under doubling of the ambient precipitation condition. When the degradation of asphalt and geomembrane after 100 years of closure was considered, the infiltration flux significantly increased almost to the design criteria of cover system in I' Aube disposal facility. And it was found that the hydraulic conductivity of bentonite/sand as a bottom barrier should be no greater than 1$\times$10$^{-7}$ cm/sec recommended by U.S. EPA.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.227-231
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• 2004

Technological advance in information technology has sparked the necessity of small form factor (SFF) optical disk for mobile devices. Small form factor optical disk is highly anticipated to be a next generation storage device because it can be used for a cost-effective way compared with solid state memory. For the application to the 5 mm height small-form-factor optical disk drive, we have presented an optical flying head and swing arm actuator. In this study, we propose a small 1-axis actuator for compensating ficus error and SA due to the variation of cover-layer thickness in the cover-layered small optical disk. The main design issues of the 1-axis actuator are the realization of compact structure and the new support structure of the actuator: Finally, the compensating principle and performance of the 1-axis actuator will be explained.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1408-1411
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• 2005

The purposes of daily cover are to control odor and volatile organic compound emissions, to control litters, to mitigate rainfall infiltration. Under usual operation of landfill, the soil layer of 15cm thick is used for daily cover, but about $20{\sim}$25% of landfill capacity is consumed by daily cover volume. Considering our limited land and difficulty in getting landfill site, developing an alternative daily cover material which usually occupies much less volume than soil will be very significant. Also, if we can use waste material for alternative daily cover, we can get additional benefit of recycling waste.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.346-350
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• 2004

In Blu-ray(BD) optical system, as a short laser wavelength of laser diode and thin cover layer thickness of' disc, the proper adjustment of spherical aberration should be performed. Considering thin cover layer' thickness and tolerance variation of disc in BD optical system, spherical aberration in BD format is mort: serious than CDㆍDVD format Especially, in dual-layer disc, to compensate the aberration at each layer, optical component should be moved finely in the way of optical path. In this study, 1 -axis moving actuator was introduced as the method of compensating the spherical aberration, and the mechanism of the system was described. Finally, its effect on optical system will be mentioned.

• Asian-Australasian Journal of Animal Sciences
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• 제14권4호
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• pp.553-558
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• 2001

The effect of poor feather cover on feed intake and production was examined in two commercial strains of layers (tinted and brown egg) over 91-98 weeks of age. Hens were housed at four per cage ($600cm^2/bird$) in a commercial layer shed which ranged in temperature from 13.2 to $16.8^{\circ}C$. At the start of the experiment 50% of the birds were classified as having poor feather cover. Feather score was highly correlated with feed intake. Poor feather cover on the neck and the back were the best indicators of hens with high feed intake. Feed intake of hens with poor feather cover was 16% higher (p<0.05) than hens with good feather cover. Hens with good feather cover produced more eggs (p<0.05) early in the trial and had a higher (p<0.05) liveweight, but there was no significant differences in egg weight. Feed per dozen eggs was superior (p<0.05) in hens with good feather cover. Feather cover on the back and vent were the best indicators of overall feather score, while the tail, base of tail and vent were the body parts most affected in birds with poor feather cover.

• 한국소음진동공학회논문집
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• 제25권3호
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• pp.150-159
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• 2015

An experimental study on frequency characteristics of the microphone array covered with Kevlar sheet was conducted in the closed test section. Microphones that were flush-mounted in the wall of wind tunnel were subjected to very high flow noise resulting from the turbulence in the wall boundary layer. This noise interference by the boundary layer was referred as 'a microphone self-noise' and various approaches were studied to reduce this interference. Recessed microphone array with high tensioned cover was one of the good approaches to reduce this self-noise. But, the array cover could cause an unexpected interference to the measuring results. In this paper the frequency characteristics of the microphone array with Kevlar cover was experimentally studied. The white noise was used as a reference noise source. Three kinds of tensions for the Kevlar cover were tested and those results were compared with the test results without the Kevlar cover. The gap effect between the cover and microphone head was also tested to find out the proper position of microphone in the array module. Test results show that the mid-tension and 10mm gap was the best choice in the tested cases.

• 환경영향평가
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• 제19권2호
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• pp.117-125
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• 2010

Korea's researchers have recently studied the prediction of forest change, but they have not considered landuse/cover change compared to distribution of forest vegetation. The purpose of our study is to predict forest vegetation based on landuse/cover change on the Korean Peninsula in the 2090's. The methods of this study were Multi-layer perceptrom neural network for Landuse/cover (water, urban, barren, wetland, grass, forest, agriculture) change and Multinomial Logit Model for distribution prediction for forest vegetation (Pinus densiflora, Quercus Spp., Alpine Plants, Evergreen Broad-Leaved Plants). The classification accuracy of landuse/cover change on the Korean Peninsula was 71.3%. Urban areas expanded with large cities as the central, but forest and agriculture area contracted by 6%. The distribution model of forest vegetation has 63.6% prediction accuracy. Pinus densiflora and evergreen broad-leaved plants increased but Quercus Spp. and alpine plants decreased from the model. Finally, the results of forest vegetation based on landuse/cover change increased Pinus densiflora to 38.9% and evergreen broad-leaved plants to 70% when it is compared to the current climate. But Quercus Spp. decreased 10.2% and alpine plants disappeared almost completely for most of the Korean Peninsula. These results were difficult to make a distinction between the increase of Pinus densiflora and the decrease of Quercus Spp. because of they both inhabit a similar environment on the Korean Peninsula.

• 한국지반공학회논문집
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• 제26권7호
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• pp.81-91
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• 2010

기존의 최종복토시스템에 대한 문제를 해결하기 위한 단층형 복토시스템의 복토재로서 석탄회(저회)의 활용성을 검토하기 위해서 현장대형토조시험을 수행하였다. 산업부산물의 관련 활용규정에 준하여 석탄회를 일반토사와 혼합하여 현장에서 설치한 대형토조에 채워 넣어 관측기간동안(2007년 7월~2008년 2월) 단층형 복토시스템의 복토재로 서 그 활용성를 일반토사만을 채운 처리구 그리고 일반토사에 건설폐기물을 혼합한 처리구와 함께 비교하였다. 그 결과 일반토사에 석탄회를 적용시킨 처리구가 매립지의 복토재로서 우선시 되는 수분저류능력과 식물의 생육면에서 가장 좋은 결과가 나타났다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제13권3호
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• pp.241-251
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• 1991

During the condylar shaving procedure, the articular soft tissue cover can be removed. Author compaired the histological healing process of the articular soft tissue cover between the preservative and unpreservative group group with 45 New Zealand rabbits(Average wt. : about 2.5kg). In unpreservative group, the usual high condylar shave with the removal of soft tissue cover was performed. In the preservative group, the underlying bone, replaced in its original position and sutured. The animals were sacrified 1, 2, 3, 4, 6 weeks interval after operation. The specimens were fixed in 10% neutral formalin and decalcified, paraffin embedded and stained by Hematoxylin & Eosin, and Masson's trichrome. The obtained results were as follows. 1. The condyles of the both group were covered with an articular sop tissue layer. 2. The cartilage cells in subarticular layer has regular continuous patterns in the preservative group but frequently interrupted in the unpreservative group. 3. The incision made in the posterior part of the articular surface for the elevation of the articular soft tissue frequently caused a deformity such as the interruption of the subarticular layer of cartilage. 4. By the above findings, the preservation of articular sop tissue cover may be the effective operation method on concept of bone remodelling.

• Geomechanics and Engineering
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• 제28권3호
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• pp.265-281
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• 2022

A set of slurry shield test system capable of cutter cutting and slurry automatic circulation is used to investigate the deformation characteristics, the evolution characteristics of support resistance and the distribution and evolution process of earth pressure during excavating and collapsing of slurry shield tunneling in circular-gravel layer. The influence of cover-span ratio on surface subsidence, support resistance and failure mode of excavation face is also discussed. Three-dimensional numerical calculations are performed to verify the reliability of the test results. The results show that, with the decrease of the supporting force of the excavation face, the surface subsidence goes through four stages: insensitivity, slow growth, rapid growth and stability. The influence of shield excavation on the axial earth pressure of the front soil is greater than that of the vertical earth pressure. When the support resistance of the excavation face decreases to the critical value, the soil in front of the excavation face collapses. The shape of the collapse is similar to that of a bucket. The ultimate support resistance increase with the increase of the cover-span ratio, however, the angle between the bottom of the collapsed body and the direction of the tunnel excavation axis when the excavation face is damaged increase first and then becomes stable. The surface settlement value and the range of settlement trough decrease with the increase of cover-span ratio. The numerical results are basically consistent with the model test results.