• Ocean and Polar Research
• /
• 제36권4호
• /
• pp.373-381
• /
• 2014

Korea contract Mn-nodule field in the NE equatorial Pacific is composed of seven sectors with average water depths of 4,513-5,025 m. Of the various factors controlling the properties of Mn-nodule, it seems that water depth is likely connected to the chemical composition and occurrence of nodules. To test whether such an assumption held in each sector, we reviewed previous research data accumulated since 1994 for one of the northern sectors (hereafter KR1) where there are stark contrasts in water depth. High-resolution seabed mapping clearly separates a northern part (KR1N) from a deeper southern part (KR1S), cutting across in the middle of the KR1. In addition, significant volcanic activities forming numerous seamounts are distinctive especially in KR1N. In terms of nodule occurrence, manganese nodules in KR1S are comparatively larger (2-4 cm) with a discoidal shape, while those in KR1N are generally small (<2 cm) with poly-lobate and irregular shapes. Nodules in KR1N also have lower Co, Cu, Mn and Ni, and higher Fe contents. The spatial separation in nodule characteristics might be caused by volcanic activities in KR1N rather than water depth contrast. During the formation of the seamounts in KR1N, rock fragments and volcanic ashes as new nuclei of the nodules would have been continuously generated. As a result, the nodules could not grow larger than 2 cm and display the shapes of a newbie (i.e., irregular and poly-lobate shapes). Moreover, significant Fe supply from volcanic activities probably decreases the Mn/Fe ratio, which may lead to the KR1 nodules being misinterpreted as a hydrogenic in origin compared to other sectors where a high Mn/Fe ratio is present.

• Proceedings of the Korean Geotechical Society Conference
• /
• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
• /
• pp.766-777
• /
• 2008

Currently in increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method (NATM). Successful design, construction and maintenance of NATM tunnel demands prediction, control and monitoring of ground displacement and support stress high accuracy. A magnetic anisotropy sensor is used for nondestructive measurement of stress on surfaces of a ferromagnetic material, such as steel. The sensor is built on the principle of the magneto-strictive effect in which changes in magnetic permeability due to deformation of a ferromagnetic material is measured in a nondestructive manner, which then can be translated into the absolute values of stresses existing on the surface of the material. This technique was applied to measure stresses of H-beams, used as tunnel support structures, to confirm expected measurement accuracy with reading error of about 10 to 20 MPa, which was confirmed by monitoring strains released during cutting tests The results show that this method could be one of the promising technologies for non-destructive stress measurement for safe construction and maintenance of underground rock structures encountered in civil and mining engineering.

• Proceedings of the Korean Geotechical Society Conference
• /
• 한국지반공학회 2010년도 춘계 학술발표회
• /
• pp.1392-1397
• /
• 2010

Currently in increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method(NATM). Successful design, construction and maintenance of NATM tunnel demands prediction, control and monitoring of ground displacement and support stress high accuracy. A magnetic anisotropy sensor is used for non-destructive measurement of stress on surfaces of a ferromagnetic material, such as steel. The sensor is built on the principle of the magneto-strictive effect in which changes in magnetic permeability due to deformation of a ferromagnetic material is measured in a non-destructive manner, which then can be translated into the absolute values of stresses existing on the surface of the material. This technique was applied to measure stresses of H-beams, used as tunnel support structures, to confirm expected measurement accuracy with reading error of about 10 to 20MPa, which was confirmed by monitoring strains released during cutting tests The results show that this method could be one of the promising technologies for non-destructive stress measurement for safe construction and maintenance of underground rock structures encountered in civil and mining engineering.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 한국분말야금학회 1994년도 춘계학술대회강연 및 발표대회 강연및 발표논문 초록집
• /
• pp.6-6
• /
• 1994

Har dmaterials such as cemented carbides with or without coated layer, cermets, ceramics and diamond or c-BN high pressure sintered compact are used for cutting tools, wear -resistant parts, rock drilling bits and/or high pressure vessels. These hardmaterials contain not only hard phase, but also second consituent as the element for forming ductile phase and/or sintering aid, and the mechanical properties of each material depend on (1) the amount of the second constituent as well as (2) the grain size of the hard phase. The hardness of each material mainly depends on these two factors. The fracture strength, however, largely depends on other microstructur a1 factors as well as the above two factors. For all hardmaterials, the fracture strength is consider ably affected by (3) the size of microstructur a1 defect which acts as the fracture source. In cemented carbides, the following factors which are generated mainly due to the addition of the second constituent are also important; (4) the variation of the carbon content in the normal phase region free from V-phase and graphite phase, (5) the precipitation of $Co_3$ during heating at about $800^{\circ}C$,(6) the domain size of binder phase, and (7) the formation of ${\beta}$-free layer or Co-rich layer near the surface of sintered compacts. For cemented carbides coated with thin hard substance, the important factors are as follows; (8) the kind of coated substance, (9) the formation of ${\eta}$-phase layer at the interface between coated layer and substrate, (10) the type of residual stress (tension or compression) in the coated layer which depends on the kind of coating method (CVD or PVD), and (11) the properties of the substrate, and (12) the combination, coherency and periodicity of multi-layers. In the lecture, the details of these factors and their effect on the strength will be explained.

• Journal of the Korean Society of Costume
• /
• 제65권2호
• /
• pp.105-124
• /
• 2015

This research was started to study how the design identity of an overseas fashion house was formed, changed and connected. For the purpose of the study, Saint Laurent House was selected as the subject of the study, because it began as a couture house and launched the $pr\hat{e}t-\grave{a}-porter$ for the first time among the designer brands, and also contributed to the development of modern women's fashion. Literature survey on related books and papers was performed to study the Saint Laurent House. Then, fashion collection photos of the house from 1962 SS to 2014 SS were collected to analyze and compare the features of the designs. The photos were collected from related books, fashion magazines and internet sites. The results are as follows: The features of Yves Saint Laurent's early designs were contemporarily sensational with their couture tradition. His representative designs including Le Smoking, Pea Coat, Loose Fit Blouse, Safari Look, Jumpsuit, Ethnic Look and Art Look became the signature looks of the Saint Laurent House. His designs expressed the liberation of sex, multi-cultural sensitivity and the fusion of art and fashion. His successor, chief designer Tom Ford designed with strong sensitivity of his own. He dealt with Yves Saint Laurent's design themes and signature looks in sensual as well as trendy and sophisticated way. Stefano Pilati showed the Parisienne chic and elegance. He re-made the legacies of Yves Saint Laurent with his own design style using new materials or cutting technique. Hedi Slimane reinterpreted the signature looks of the house with his rock' n roll mood for young, modern women while reflecting the spirit of Yves Saint Laurent's early stage. In conclusion, the design identity of Saint Laurent House is not just a fixed one. By the subsequent chief designers, the signature items and design spirit of Yves Saint Laurent have been succeeded, reintroduced or changed to be trendy and to reflect the designers' design sensitivity. All of these make and maintain the design identity of the fashion house.

• The Journal of Engineering Geology
• /
• 제30권4호
• /
• pp.447-456
• /
• 2020

The study area is a slope in Dogye-eup, Samcheok-si, Gangwon-do. The cutting method was applied to this slope for stabilization in 2009 due to the influence of the waste-rock dump located at the top of slope. Recently, soil cracks and creep have occurred on this slope, and the drainage channel was damaged. Therefore, it was analyzed the topography change through photogrammetry using a UAV. Orthophotos were taken in April and October 2019 respectively. From the Orthophots, Digital Surface Model (DSM) was extracted. Time series analysis was performed by comparing each DSM. The topography of October was pushed forward while maintaining the topography of April. Through these features, it is judged that the soil creep is occurring in this study area.

• Journal of Practical Agriculture & Fisheries Research
• /
• 제24권4호
• /
• pp.35-44
• /
• 2022

This study was conducted to develop a mass production for a commercial use by cutting of 4 kinds of V. glabrifolia Kitag., V. pusanensis Y.N.Lee, V. glabrifolia Kitag. × V. Spicata 'Alba' and V. spicata 'Ulster Blue Dwarf' × V. longifolia. Veronica L. Effects of shade, media and concentrations of plant growth regulators on the rooting of Veronica L. were examined. The rooting rate of V. glabrifolia Kitag. was higher as a 60% than the V. pusanensis Y.N.Lee as a 20% in the control of commercial media. In shading treatment, the rooting rate was highest at 30% or 60% shading, and the 30% shading was the best in number of root and root length, but the 90% shading was lower than no shading treatment. For cutting media, the rock wool and 100% perlite increased the rooting rate by more than 10% compared to commercial media, and increased the number of roots by 2 or 3 times. However the Cocopeat of media was lower of rooting rate, root number, and root length compared to another treatment. In the plant growth regulator treatment, the rate of rooting increased in all treatment compared to control, and was highest at IBA 1,000mg·L^-1 as a 82.2% and NAA 200 or 400mg·L^-1 as a 82.2% or 84.4% respectively, in the V. glabrifolia Kitag. × V. Spicata 'Alba'. However, the root number and root length was decreased as the concentration of growth regulators increased.

• Journal of the Korean GEO-environmental Society
• /
• 제15권1호
• /
• pp.53-62
• /
• 2014

In Korea, in general, separation distance between existing parallel tunnels was set at two to five times as distant as the diameter of the tunnels according to ground conditions. Recently, however, actual applicability of closely spaced parallel tunnels whose distance between tunnel centers was shorter than the diameter has increased due to environmental damages resulting from massive cutting, restriction in purchase of required land, and maintenance of linear continuity. In particular, when the pillar width of tunnel decreases, the safety of pillars affects behaviors of the tunnel and therefore the need for diverse relevant studies has emerged. However, research so far has been largely confined to analysis of behavior characteristics of pillars, or parameters affecting design, and actually applicable and quantitative data have not been presented. Accordingly, in order to present a stability evaluation method which may maximally reflect construction conditions of spots, this study reflected topographical and stratigraphic characteristics of the portal part with the highest closeness between the tunnels, simulated multi-layer conditions with rock mass and complete weathering, and assessed the degree of effect the stability of pillars had on the entire tunnels through numerical analysis according to changes in pillar width by ground strength. This study also presented composite analysis result on ground surface settlement rates, interference volume rates, and average strength to stress and a formula, which may be applicable to actual work, to evaluate safety rates of closely spaced parallel tunnel pillars and minimum pillar width by ground strength based on failure criteria by Hoek-Brown (1980).

• Journal of Korean Society of Forest Science
• /
• 제87권1호
• /
• pp.82-89
• /
• 1998

This study was carried out to investigate working time, performance, and to predict performance that related to the factor of forest road in earth work using excavator. It was found that the real working time was 503 minutes in a day. The ratio of real working time and allowance per total working time was approximately 85.7% and 14.3% individually. The rate of soil movement(Sm) to net working time was 38.6%, and earth cutting(Ec) was 32.5%. According to performance analysis, performance of earth work using excavator($0.8m^3$) in straight part was 1.4 times larger than curve part and rock work using excavator($0.8m^3$) which had breaker in straight was 9.1 times larger than earth work using excavator($0.8m^3$) which had bucket. Performance of earth work using excavator($1.0m^3$) was 1.3 times larger than using excavator($0.8m^3$) in straight and curve part. Working performance in earth work using excavator($0.8m^3$) was influenced by the conditions of radius of curve, width of roadway, slope gradient. It is not influenced by diameter and number of root stock.

• Journal of the Korean Society for Marine Environment & Energy
• /
• 제11권2호
• /
• pp.86-91
• /
• 2008

Ships operating in littoral sea are likely to be subjected to accidental load such as stranding. Once she has damage on the hull structure, her ultimate strength will be reduced. This paper is to investigate the effect of the stranding damage on ultimate strength of ship structure by using a series of collapse tests. For the experiment, 720 mm $\times$720 mm in section and 900mm in length of five box-girder models with stiffeners were pre- pared. Of the five, one has no damage and faur have an diamond shaped damage which represents the shape of rock section in seabed. The damage size is different between models. Among the damaged models, the damages of 3 of them were made by cutting the plate and one by pressing to represent stranding damage. Experiments were carried out under pure bending load and the applied load and displacements were recorded. The ultimate strength is reduced as the damage size increases, as expected. The largest damaged model has the damage size of 30% of breadth and its ultimate strength is reduced by 21% than that of no damaged one. The pressed one has lower ultimate strength than cut one. This might be due to the fact that the plate around the pressed damage area effect negatively on the ultimate strength.