• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.136-137
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• 2007

Wear resistant TiAlN thin film has been widely deposited on the surface of cutting and forming tools by using Arc Ion Plating. TiAlN films are deposited by the processes designed by the Taguchi L18 experimental design. The L18 experimental design is applied to achieve surface properties and adhesion. The deposition parameters are working pressure, substrate temperature, bias voltage, arc power and pre-sputtering bias voltage and time. The most influential parameters on surface properties and adhesion are substrate bias voltage, working nitrogen pressure and arc power. The optimal coating processes are obtained for surface properties and adhesion.

• Ocean and Polar Research
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• v.43 no.4
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• pp.353-363
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• 2021

Fluorescent dissolved organic matter (FDOM) is referred to organic matter which absorbs efficiently solar radiation energy and fluorescence in the water column. The component and molecular structure of marine organic matter can be changed depending on the various substances and origins of organic matter, and then the organic matter has unique fluorescent properties. As the cutting-edge analytical techniques of optical measurement continuously developing from last few decades, a study on FDOM has been applied as a biogeochemical tracer to quantify the organic matter concentration and to investigate the behaviors and origins of organic matter. Especially, the marine environment around the Korean Peninsula is an ideal research area to study FDOM because of various oceanographic characteristics and the origins of organic matter. This study describes the general properties of FDOM and introduces the cycling and behaviors of marine organic matter based on the domestic research studies.

• Korean Journal of Environment and Ecology
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• v.14 no.1
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• pp.38-45
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• 2000

This research has been done to investigate influence of soil physical and chemical properties on forest environmental change by fired pine forest in Koseong, Kangwondo. The sample sites were divided by not-fired sites(NF), not-cutting site after fired(FNC), cutting and planting sites after fired(FCP) and cutting and not-planting sites after fired(FC). Soil texture of whole sites was sandy clay loam. Sand content of NF top soil were lower than those of sub soil and clay content were higher, while FNC, FCP and FC sand content of top soil were higher than those of sub soil. Total porosity didn't differ between the sites. Coarse porosity and permeability had the increasing order as NF> FNC> FCP> FC, but fine porosity and bulk density had the opposite trends. Because forest fire removed the vegetation and then soil erosion was accelerated, forest environmental changes by forest fire greatly degraded soil porosity and permeability which were indices for forest water retention, so that soil physical properties were deteriorated. Both top and sub soil pHs of NF and FNC were higher than those of FCP and FC. Organic matter content and total nitrogen content of top and sub soils were high in order as NF> FNC> FCP> FC. Cation exchange capacities and exchangeable cation(K+, Na+, $Ca^2$+, $Mg^2$+) content in top soils were higher than those in sub soils, and in order as NF> FNC> FCP> FC, to be compared by the sites. Those mean that forest fire result from the erosion of top soil layers.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.04a
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• pp.35-35
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• 1997

High$\cdot$speed steels (HSS) with a combination of good wear resistance and toughness are finding new, non-cutting applications such as rolls and rollers. In this paper, the research interests are focused on the microstructural evolution of a SMo-6W series high speed steel during HIPping and the effect of HIPping process parameters on its microstructure and properties. HIPping process variables includes; temperature, pressure and hold time. The microstructures of the HIPped HSS were examined by SEM, OM and X-ray diffraction whereas the properties measured were the relative density, hardness, and bend strength at room temperature. In HIPped materials, MC and M6C were the major carbides formed in a matrix of martensite. The effect of powder size on the microstructure and mechanical properties of HIPped materials was insignificant. However, HIPping temperature and hold time strongly affected the carbide size and distribution. The results show that at proper HIPping temperature and pressure conditions, the final products approach the full density ( > 99% RD). The particle boundaries were completely eliminated without an eminent microstructural coarsening. The bend strength was about 2.3 Gpa, which is superior to cast HSS. At excessive HIPping temperatures, rapid carbide coarsening occurred, thus deteriorating the mechanical properties of the P/M steels.

• Journal of the Korean Ceramic Society
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• v.27 no.1
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• pp.102-108
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• 1990

WC-Co composites are widely used as cutting or drilling tools because of their high hardness, strength, and fracture toughness. The working temperature is, however, generally in the range of 300-$700^{\circ}C$ so thermal shock fracture of WC-Co can occur. In this study, the strength, fracture toughness and fracture surface of 16wt% Co bonded tungsten carbide composites before and after thermal shock were observed.

• Economic and Environmental Geology
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• v.13 no.2
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• pp.80-90
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• 1980

A geologic disasters in Ulreung-island is forming along the slope of pyroclastic, deposits and this paper discusses soil mechanics and properties and morphologies of pyroclastic soil. The typers of degradation are determined by cutting the soil and classified genetically. Finally, the range of stability is deduced from dip of slope (${\alpha}$) and lengh of slope (l) as the following;.

• Proceedings of the KWS Conference
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• 2008.05a
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• pp.47-47
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• 2008

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.183-190
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• 2001

There are complicated and big shear zone which is about several tens meter in the middle of the cutting slope in this study area. And slope stability analysis is very hard because many fault zones are gathered in the shear zone. This study furnish imformations of scrutinized geological survey, numerical stability analysis, reinforcement work analysis and computation of ground mass properties. Then this offer rational slope stability analysis, rock mass decision and counterplan.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.579-584
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• 2000

Single crystal silicon (SCS) is used in a variety of microsensor applications in which stresses and other mechanical effects may dominate device performance. The authers model temperature dependent mechnical properties during focused io beam(FIB) cutting and Pt deposition processes. In microaccelero-meter manufacturing process, this paper intend to find thermal displacement change of the temperature by tunnel gap, additional beam part and pt deposition. The thermal analysis intend to use ANSYS V5.5.3.

• Tunnel and Underground Space
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• v.23 no.3
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• pp.180-191
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• 2013

The purpose of this research was to find an optimal quarrying for marble by analyzing the applicability and the work efficiency of a chain saw machine newly introduced in the underground Baekwoon mine. From the test results of the physical properties of Baekwoon marble, which affects the efficiency of rock cutting, it was found to have similar physical characteristics as the ones which are now being produced in the other areas in Korea. And especially it shows isotropic property, which can be thought to be advantageous as a dimensional stone. To check the long-term quality of the marble as a stone material, several tests such as corrosion resistance test and abrasion test were carried out. It was found to be vulnerable to acid rain with decrease of weight and seismic wave velocity after applying artificial rain at pH 5.6 for 50 times. The percentage of wear from abrasion test was 22.67%. The working time and cutting speed of the chain saw machine were recorded and analyzed during the test-run at the quarry. The overall work cycle was assorted into 9 unit operations and the operating time per each unit was drawn. The operating times for the two cutting patterns, which could be possibly applicable to the work site, were compared. The results indicated that the pattern B, that the cutting sequence was set to minimize the movement of the machine, showed 6% less working hours than the pattern A, which first cuts the outer boundary. With cutting pattern analysis, the ore body in the Baekwoon mine was 3 dimensionally modeled and a quarrying plan considering the existing conditions of the marble was suggested.