• 한국농공학회지
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• 제23권4호
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• pp.41-45
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• 1981

This study is to be surveyed the rural environmental conditions such as housing, water works, sewerage, road and farm road, land utilization, natural conservation and sightseeing, public damage and disaster, and rural water requirement through the 50 villages (10995 home unit) The brief results summarized in this study are as follows. 1.Modernization of rural housing, toilet room and arrangement of dust materials are getting better than before l0yrs. 2.Water works are highly improved but sewerage problem is still in the serious problems. 3.Rood achievement is quite good but farm road is in still insufficiency 4.Utilization of land resources should be maximaized but land conservation is still insufficient condition and farm land is getting polluted. 5.Natural environmental conservation is much more improved but landscape is still insufficient. 6.Public damages such as water pollution, air pollution, and others are getting greater and greater but meteorological damage should be decreased. 7.Watershed condition is getting better and better but because of the large requiriment of the water use for the crops, agricultural water use should be needed much more than before l0yrs.

• 한국도로학회논문집
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• 제15권1호
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• pp.47-56
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• 2013

PURPOSES: This study is to evaluate a ground water level effect on frost heaving in road pavements. METHODS: The effects of water table on frost heaving in pavement systems were evaluated from the mechanical analysis using FROST program. The input parameters and boundary conditions were determined by considering climates, pavement sections, and material properties specially subgrade soil types in Korea. RESULTS: When the water table located above the freezing depth, amount of frost heaving caused by freezing the water in pavement itself was big enough to damage in pavement system, although pavement system consists of fully non-frost-susceptible materials with sufficient thickness of anti-freezing layer. The amount of frost heaving was decreased rapidly with increasing the distance between the water table and freezing depth. CONCLUSIONS: It was concluded that there is no engineering problems related with frost heaving in practical sense when the distance between freezing depth and water table is over 1.5m for having subgrade soils less than 50% of #200 sieve passing to meet specification on quality control in Korea.

• Acta Via Serica
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• 제8권2호
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• pp.53-78
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• 2023

The paper presents some new results illustrating some developments related to the concept of the Silk Road and subsequent methodological reflections. New laboratory results of scientific analyses of plants, minerals, and human remains in combination with more conventional methods of research contribute to a better understanding of the multidirectionality of exchanges in Pre- and Protohistory. Unsuspected long-distance transfers of items, especially of metals (tin) and biological materials (plants, pathogens, etc.) are discovered. Adding ancient DNA and petroglyphs to the vexed question of the Indo-European migrations across Eurasia complexifies the familiar linguistic, historical, and archaeological research landscape. Recent excavations show the impact of the adoption of artistic elements adapted from the Achaemenid arts, far in the steppe world, and up to China. Multidirectional (including North-South lanes) and multidisciplinary approaches leave space and hope for more rigorous scientific modelizations for the archaeology of Eurasia and the Silk Road.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.489-493
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• 2001

Big cities in Japan have serious problems due to the shortage of new reclaimed land for municipal wastes. If harmful heavy metals such as cadmium, lead, copper and etc. are contained in the municipal waste combustion residues, they are not able to fill up according to the environmental law in Japan. In this study, the removal of heavy metals in the fly ash (EP ash) was dealt with chloridizing vaporization method. EP ash as a non-hazardous materials is utilized as covering materials, road bed, and building materials.

• Advances in concrete construction
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• 제4권1호
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• pp.15-26
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• 2016

In Algeria, wastes are often stored in such conditions that do not meet standards. Today and more than ever, we really must implement an environmentally management of wastes. Recovery of waste in Algeria has a considerable delay due to the absence of a policy favorable to the development of waste management. But many researchers have shown the possibility to reuse dredged sediments in road construction. Through Europe, recent research works have been already performed on dam sediments. Present study fits into the context of the valorization of dredged sediments from Fergoug dam. They are found in considerable quantities and mainly composed of mineral phases, organic matters and water. The reservoir sedimentation poses problems for the environment and water storage, dredging becomes necessary. Civil engineering is a common way of recycling for such materials. Dredged sediments have not the required mechanical characteristics recommended by the standards as GTR guide (LCPC-SETRA 1992). So as to obtain mechanical performance, dredged sediment can be treated with cement, lime, or replaced materials like quarry sand. An experimental study has been conducted to determine physical and mechanical characteristics of sediments dredged from dam. Then different mixtures of sediment and/or quarry sand with hydraulic binders are proposed for improving the grain size distribution of the mixes. Finally, according these mixtures, different formulations have been tested as alternative materials with dredged sediments.

• 자원환경지질
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• 제25권3호
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• pp.317-336
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• 1992

The garden soils, main road dusts, residential road dusts, and playground soils/dusts of Seoul, Geumsan, Onsan, and Taebaek areas were analyzed in order to investigate the level of heavy metal pollution by urbanization and industrialization. The soil pH is in the range of 5.48~8.40 and was generally neutral. The color of soils and dusts is mainly Raw Umber to dark greyish Raw Umber. Some samples from Taebaek city, a coal mining area, showed a deep black color due to contamination by coal dusts. Major minerals of the dusts and soils are quartz, feldspars, and micas, reflecting the composition of the parent rocks. However, pyrite was found as a major mineral in the samples of industrial road dusts of Onsan, a smelting area, and resicential road dusts of Taebaek. Thus, the high level of heavy metals in mining and smelting areas can be explained with the sulfide minerals. The mode of occurences of heavy metals in Seoul, a comprehensive urbanized area, were related to the metallic pollutants and organic materials through observation by scanning eletron microscopy. In main road and residential road dusts of Onsan area, Cd, Zn, and Cu were extremely high. Some industrial road and residential road dusts of Seoul area showed high Cu, Zn, and Pb contents, wereas some garden soils and residential road dusts of Taebaek area were high in As content. In general, the heavy metal contents in dust samples were two to three times higher than those in soil samples. Main road dust samples were the most reflective from the discriminant analysis of multi-element data. Cadmium, Sb, and Se in Onsan area, As in Taebaek area, Pb and Te in Seoul area were most characteristic in discriminating the studied areas. Therefore, Cd in smelting areas, As in coal mining areas, and Pb in metropolitan areas can be suggested as the characteristic elements of each pollution pattern. The dispersion of heavy metal elements in urban areas tends to orignate in main roads and deposit in garden soils through the atmosphere and residential roads. The heavy metal contamination in Seoul is characteristic in areas with high population, factory, road, and traffic decsities. Heavy metal contents are high in the vicinity of smelters in Onsan area and are decayed to background levels from one kilometer away from the smelters.

• 한국전기전자재료학회논문지
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• 제23권6호
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• pp.471-476
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• 2010

This paper has studied dissymmetrical light distribution design using the secondary optics in the simulation. fundamental Lambertian radiation distribution based on LED has been cut off by the secondary optics, and the first surface slope of lens and second surface slope of total reflection area have been calculated through formula. PMMA (the index of refraction: 1.49361) which is material of lens has been selected. critical angle($42.02993^{\circ}$) between Air and PMMA has been calulated by snell's law, and total reflection angle slope has been selected about $16.67^{\circ}$ to occur the total reflection. when the first surface slope and the second surface slope has been set up, Rays of all total reflection area have generated the total reflection. finally, designed LED Module has been estimated by Korean Industrial Standards for LED safety street lighting. dissymmetrical light distribution have been analyzed with reached effect of road illuminance, and average road illuminance which are each 70.6 lx, 40.35 lx, and 25.88 lx have been satisfied with Korean Industrial Standards for LED safety street lighting.

• Structural Engineering and Mechanics
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• 제71권3호
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• pp.283-290
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• 2019

In global competition manufacturing companies have to produce modern, new constructions from advanced materials in order to increase competitiveness. The aim of my research was to develop a new composite cellular plate structure, which can be primarily used for structural elements of road, rail, water and air transport vehicles (e.g. vehicle bodies, ship floors). The new structure is novel and innovative, because all materials of the components of the newly developed structure are composites (laminated Carbon Fiber Reinforced Plastic (CFRP) deck plates with pultruded Glass Fiber Reinforced Plastic (GFRP) stiffeners), furthermore combines the characteristics of sandwich and cellular plate structures. The material of the structure is much more advantageous than traditional steel materials, due mainly to its low density, resulting in weight savings, causing lower fuel consumption and less environmental damage. In the study the optimal construction of a given geometry of a structural element of a road truck trailer body was defined by single- and multi-objective optimization (minimal cost and weight). During the single-objective optimization the Flexible Tolerance Optimization method, while during the multi-objective optimization the Particle Swarm Optimization method were used. Seven design constraints were considered: maximum deflection of the structure, buckling of the composite plates, buckling of the stiffeners, stress in the composite plates, stress in the stiffeners, eigenfrequency of the structure, size constraint for design variables. It was confirmed that the developed structure can be used principally as structural elements of transport vehicles and unit load devices (containers) and can be applied also in building construction.

• 한국환경복원기술학회지
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• 제6권4호
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• pp.74-84
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• 2003

This study focuses on the technology to reduce destruction and damages of an ecosystem in the process of road construction. The authors investigated the ecological conservation activities and restoration technology which were applied to the construction of 2 bridges in Japan. The key results are as following : First, the most important thing in constructing eco-road was the linear design. Second, we need to adopt the environmental construction forms and materials to the design of structure. Finally, we have to use environment-friendly methods for the sake of the ecosystem at the real construction stage. Adopting those technologies has at least a few merits. First, we can achieve out goals : conservation and restoration in the local habitat. Second, we can save money instead of building a eco-bridge. There is a further advantage which makes it possible to develop environment-friendly technologies than before by drawing developers' attention.

• 소성∙가공
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• 제23권2호
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• pp.116-121
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• 2014

Low pressure die casting and flow forming have been successfully used to produce sound road wheels from magnesium alloy AM80. In the current study, high speed compression testing was initially conducted to simulate the flow forming of a Mg wheel. Subsequently the flow forming was simulated with "Forge$^{TM}$", an FEM software package. On the basis of flow forming simulations, the flow forming of the Mg wheel was performed under different conditions. For the flow forming experiments, the preform castings were made by low pressure die casting from AM80, a commercial magnesium alloy. In flow forming of the magnesium preform wheel, the flow forming of the Mg wheel was successfully accomplished when the feed rate was less than half that for the forming of an aluminum road wheel. The reduction in feed rate was 52%. Finally, a comparison with the flow forming simulations was made.