• Journal of Korea Foundry Society
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• v.32 no.1
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• pp.24-31
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• 2012

In this study, semi-solid thin plate of A 356 aluminum alloy was fabricated by using slope plate apparatus and vacuum pressurization. Slope plate was used to produce semi-solid material with spheroidal microstructures. After molten metal was poured into the slope plate connected to the pouring hole of die, semi-solid material flowed into the die cavity by vacuum degree. The primary crystals of the cast metal became spheroidal. In order to increase the working pressure, gas pressurization of U shape was designed for fabrication of thin plate. For 3 bar of gas pressure and 60 mmHg of vacuum degree, thin plate was fabricated without defects on surface.

• Tunnel and Underground Space
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• v.25 no.1
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• pp.76-85
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• 2015

We have developed a software to predict failure time of the rock slope based on analysis of the data from real time displacement measurements with respect to time. The software consists of four modules that play roles in analytical methods such as inverse velocity method, log time-log velocity method, log velocity-log acceleration method and nonlinear least square method to estimate failure time. VisualBasic.NET on the MS Visual Studio platform was utilized as a development tool to efficiently implement the modules and the graphical user interface of the software. Displacement data obtained from laboratory physical model studies of plane sliding were used to explore the applicability of the software, and to evaluate the possibility of predicting potential slope failure. It seems possible to estimate failure time using developed software for sliding plane having exponential type of deformability.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.69-75
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• 2014

Rock fall protection system installed against rock slope is one of the most conventional way to protect nearby infra structures. Despite of wide application of typical rectangular nets, virtually installed to protect rock slope face, several problems have also been pointed out up to date. Rectangular draped nets are vulnerable to a sudden external shock such as rock fall, because it doesn't have any systematical buffers or shock absorbers. Furthermore, it has been widely recognized from the some cases of rock fall accident in Korea that rock fall protection nets cause wide range of failure in the rock slope faces due to insufficient pullout bearing capacity of fixing parts. Therefore, in this study, we tried to make a consideration about the problems of existing standard rock fall protection nets in Korea, and develop a new type of hexagonal net with a shock absorber based on design rock fall energy. In this paper, laboratory and full scale test procedure is described to analysis the performance of newly developed hexagonal rock fall net, and the key results are presented and discussed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.63-73
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• 1995

A remote telesounder system was manufactured to investigate the behavior and distribution characteristics of fish and was tested to verify its performance and effects int he set net fishing ground located off the Namhae island, Oct. 26~27, 1994. The activity pattern of fish was observed at the buoy station installed in a set net and it was also analyzed simultaneously at the remote base station on land located at distance of about 1.5km away from the buoy station. Several findings at both the buoy station and the base station were as follows: The images of color display monitor at the base station on land were very well coincident with the records observed at the buoy station. The lower part of slope net and bagnet fluctuated irregularly, and its variations were about 3.6m and 6.0m, respectively. In the daytime, the fish school entered playground, passed slope net with 5~7m depth, moved dispersedly at night and at twilight the entrance was rare. In the bagnet, in the daytime the fish school swam in the layer of 8m in depth, at night the fishes dispersed in the entire layer and at twilight they formed dense school. The fishes caught by the set net were about 500kg with 20 species. Anchovy was the most dominant species. In conclusion, the remote telesounder was a convenient and powerful system for investigating the distribution pattern and the swimming behavior of fish entering in set net.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.2
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• pp.97-102
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• 1987

To find out the nutrient contents of temperate grasses on the south and north slope, a field experiment was conducted with five forage species of Dactylis glomerata, Festuca arundinacea, Phleum pratense, Agrostis gigantea and Trifolium repens. It was treated by randomized block design with 4 replications and lasted from September, 1983 to October, 1986 in Suweon. The results obtained are summarized as follows: 1. Mean chemical compositions except NFE and crude fiber of the forage species on the south slope were a little more contented than that of north. But all crude components were significant difference among the species on the south and north exposure. 2. Production of TDN (total digestible nutrient), StE (starch equivalent) ME (metabolizable energy) and NEL (net energy lactation) of different grass species on the north slope were much more increased by 5-30% per ha (Dactylis glomerata by 5-876, Festuca arundinacea by 5%, Phleum pratense by 24-26% and Agrostis gigantea by 25-30%) than that of same grasses on the south, however, those of Trifolium repens were much more increased by 4 1-42% per ha in the south. 3. Mineral contents, Ca/P ratio and K/ (Ca + Mg) equivalent ratio of the species were slightly different between the exposures. But considering the factors of occuring grass tetany, those of the forage species on the north slope were better than that of same species on the south.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.2
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• pp.35-41
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• 1993

The height differences in Mean Sea Level is an important factor in geodetic leveling net, because MSL is the reference datum for height. Geodesists and Oceanographers agree on the height differences in MSL in the east-west direction, but they disagree almost always on the north-south slope, each suspecting systematic errors in the leveling methods of the others. A promising method for determining this slope is comparison of MSL at the tidal station connected by geodetic leveling. The slopes of the sea surface along the coast of Korean Peninsular is estimated from conventional local MSL at the tidal station and bench mark height of first order leveling net in Korea. As a reference level surface, MSL at Inchon is chosen. The results indicate that sea level rises along coast of Korean Peninsular from south to north about 5.5 cm/latitude. In the east-west direction, sea level along East Sea coast stands about 5 cm higher than that along Yellow Sea coast. These are not invariable but provisional phenomena. It may become certain provided that the exact MSL is estimated.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.146-152
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• 2005

For the application of ectomycorrhizal seedlings on damaged slope lands, studies on cultural characteristics of Lyophyllum shimeji and ectomycorrhizal associations of Lespedeza cyrtobotrya seedlings were carried out by artificial inoculation of L. shimeji. Mycelial growth of L. shimeji was best on MP (1% malt extract, 0.1% peptone, 1% glucose and 1.5% agar) medium. An optimum temperature and pH for the mycelial growth were $25^{\circ}C$ and pH6, respectively. Mycorrhizal root of L. cyrtobotrya seedlings inoculated with L. shimeji showed characteristics of ectomycorrhizas with Hartig net. Growth rate of the mycorrhizal seedlings's roots was higher than that of non-mycorrhizal seedlings. When the mycorrhizal seedlings were transplanted in slope land, survival rate and dry weight were 62% and 850 mg/seedling, respectively. On the other hand, survival rate and dry weight of non-mycorrhizal seedlings were 11% and 430 mg/seedling, respectively.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.77-86
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• 2000

Even manual materials handling tasks(MMHT) is decreasing by adopt of automatic manufacturing system & transportation supporting machine because of increase of productivity, wage lack of labor, safety, in fact working at inclined & complicated slope such as farm, orchard, harbor loading & unloading, logging place and mining place can't be substituted by machine perfectly. So, workers should do MMHT at this place by themselves, lifting on slope can cause much of hazard, include falling. Keeping balance net to slip can be a reason of low back pain(LBP) by overloaded musculoskeletal system but, there's no enough study about lift on slope. Therefore, In this study, we assessed and analyzed change of center of pressure(COP) when lifting on slope by force platform. The result showed that the length lengthen as increasing angle of slope. Especially, the length extremely increased over 15°. Through These basic result, present proper angle boundary, prevent industrial accidents and give proper data not only lifting but also pushing and pulling on slope someday.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.673-683
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• 2016

This paper analyzes the accuracy of the methods used in calibrating the thermal power of Nigeria Research Reactor-1 (NIRR-1), a low-power miniature neutron source reactor located at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria. The calibration was performed at three different power levels: low power (3.6 kW), half power (15 kW), and full power (30 kW). Two methods were used in the calibration, namely, slope and heat balance methods. The thermal power obtained by the heat balance method at low power, half power, and full power was $3.7{\pm}0.2kW$, $15.2{\pm}1.2kW$, and $30.7{\pm}2.5kW$, respectively. The thermal power obtained by the slope method at half power and full power was $15.8{\pm}0.7kW$ and $30.2{\pm}1.5kW$, respectively. It was observed that the slope method is more accurate with deviations of 4% and 5% for calibrations at half and full power, respectively, although the linear fit (slope method) on average temperature-rising rates during the thermal power calibration procedure at low power (3.6 kW) is not fitting. As such, the slope method of power calibration is not suitable at lower power for NIRR-1.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.367-378
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• 2002

Recently, the number of tunnels on national roads has been increased due to the trend that construction of the large-scaled cut slopes is limited because of the environmental issues. Therefore, the slope failures of tunnel portal have often occurred. The tunnel portal in use has limitations on selection of the countermeasure and construction against slope failure. In the cases of Suanbo hot springs 1 and 2 tunnel portals, seedding was chosen and constructed as the countermeasureof slope failure when the tunnel was first built but collapsed in April, 2002. In this study, the failure sites were examined accurately through the site investigation and an efficient countermeasure according to stability analysis is presented. It is shown that it is very efficient to use resloping for Suanbo hot springs 1 tunnel and concrete buttress, rock anchor to reinforcement countermeasure, and attached rockfall prevention net by dividing the site into 3 sections for Suanbo hot springs 2 tunnel.