• Geomechanics and Engineering
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• v.13 no.2
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• pp.333-352
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• 2017

A comparison study is made between the dynamic properties of an argillaceous siltstone and its grouting-reinforced body. The purpose is to investigate how grout injection can help repair broken soft rocks. A slightly weathered argillaceous siltstone is selected, and part of the siltstone is mechanically crushed and cemented with Portland cement to simulate the grouting-reinforced body. Core specimens with the size of $50mm{\times}38mm$ are prepared from the original rock and the grouting-reinforced body. Impact tests on these samples are then carried out using a Split Hopkinson Pressure Bar (SHPB) apparatus. Failure patterns are analyzed and geotechnical parameters of the specimens are estimated. Based on the experimental results, for the grouting-reinforced body, its shock resistance is poorer than that of the original rock, and most cracks happen in the cementation boundaries between the cement mortar and the original rock particles. It was observed that the grouting-reinforced body ends up with more fragmented residues, most of them have larger fractal dimensions, and its dynamic strength is generally lower. The mass ratio of broken rocks to cement has a significant effect on its dynamic properties and there is an optimal ratio that the maximum dynamic peak strength can be achieved. The dynamic strain-softening behavior of the grouting-reinforced body is more significant compared with that of the original rock. Both the time dependent damage model and the modified overstress damage model are equally applicable to the original rock, but the former performs much better compared with the latter for the grouting-reinforced body. In addition, it was also shown that water content and impact velocity both have significant effect on dynamic properties of the original rock and its grouting-reinforced body. Higher water content leads to more small broken rock pieces, larger fractal dimensions, lower dynamic peak strength and smaller elastic modulus. However, the water content plays a minor role in fractal dimensions when the impact velocity is beyond a certain value. Higher impact loading rate leads to higher degree of fragmentation and larger fractal dimensions both in argillaceous siltstone and its grouting-reinforced body. These results provide a sound basis for the quantitative evaluation on how cement grouting can contribute to the repair of broken soft rocks.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.219-226
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• 2013

Organic semiconductor-based soft electronics has potential advantages for next-generation electronics and displays, which request mobile convenience, flexibility, light-weight, large area, etc. Organic field-effect transistors (OFET) are core elements for soft electronic applications, such as e-paper, e-book, smart card, RFID tag, photovoltaics, portable computer, sensor, memory, etc. An optimal multi-layered structure of organic semiconductor, insulator, and electrodes is required to achieve high-performance OFET. Since most organic semiconductors are self-assembled structures with weak van der Waals forces during film formation, their crystalline structures and orientation are significantly affected by environmental conditions, specifically, substrate properties of surface energy and roughness, changing the corresponding OFET. Organo-compatible insulators and surface treatments can induce the crystal structure and orientation of solution- or vacuum-processable organic semiconductors preferential to the charge-carrier transport in OFET.

• Journal of the Korean earth science society
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• v.26 no.5
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• pp.443-458
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• 2005

Late Quaternary deposits of the core in the western area of the Nakdong River delta consist of four sedimentary units: Unit I, II, III and IV, in ascending order, controlled by the sea-level change since the last interglacial period. Unit I unconformable overlying Cretaceous basement rocks is composed of sandy gravel and sand deposited in a fluvial channel before the first marine transgression. Unit II composed of stiff massive mud is interpreted as a shallow marine deposits formed during the last interglacial period (probably MIS 5). The development of the fissures coated with oxidized materials in the upper part of Unit II is a feature of subaerial exposure, which indicates erosional contact with the upper Unit III. Unit III is made up of soft massive mud and soft shelly massive mud deposited in a tidal flat and a inner shelf, respectively, since the Holocene transgression (about 9,000 yr BP). Unit Ⅳ consisted of soft shell bedded mud and yellowish sandy mud was deposited in the delta environments during the regression (after about 5,000 yr BP). The lower shell bedded mud was deposited in a tidal flat and the upper sandy mud was deposited in the floodplain corresponding to present site of the Nakdong River delta.

• Journal of the Korean Geotechnical Society
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• v.21 no.9
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• pp.13-23
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• 2005

The prefabricated vertical drains (PVDs) are one of the most widely used techniques to accelerate the consolidation of soft clay deposits and dredged soil. Discharge capacity is one of the factors affecting the behavior of PVDs. In the field, a PVD is confined by clay or dredged soil, which is normally remolded during PVD installation. Under field conditions, soil particles may enter the PVD drainage channels, and the consolidation settlement of the improved subsoil may cause 131ding of the PVD. These factors will affect the discharge capacity of the PVDs. In this study an experimental study was carried out to estimate the discharge capacity of three different types of PVDs by utilizing the large-scale laboratory model testing and small-scale laboratory model testing equipments. The several factors such as confinement condition (confined by soft marine clay or dredged soil) and variations of the discharge capacity were studied with time under soil specimen confinement, The test results indicated that discharge capacity decreases with increasing load, time, and hydraulic gradient. With load application, the cross-sectional area of the drainage channel of PVD decreases because the filter of PVD is pressed into the core. The discharge capacity of the soft marine clay-confined PVDs is much lower than that of the dredged soil-confined PVDs.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.48-64
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• 1999

For quantitative evaluation of geotechnical engineering properties such as rippability and diggability, clear interpretation on the subsurface velocity structures should be preceded by figuring out top soil, weathered and soft rock layers, shape of basement, fracture zones, geologic boundary and etc. from the seismic refraction data. It is very important to set up suitable field parameters, which are the configuration of profile and its length, spacings of geophones and sources and topographic conditions, for increasing field data quality Geophone spacing of 3 to 5m is recommended in the land slope area for house land development and 5 to 10m in the tunnel site. In refraction tomography technique, the number of source points should be more than a half of available channel number of instrument, which can make topographic effect ignorable. Compared with core logging data, it is shown that the velocity range of the soil is less than 700m/s, weathered rock 700${\~}$1,200m/s, soft rock 1,200${\~}$1,800m/s. And the upper limit of P-wave velocity for rippability is estimated 1,200 to 1,800m/s in land slope area of gneiss. In case of tunnel site, it is recommended in tunnel design and construction to consider that tunnel is in contact with soft rock layer where three lineaments intersecting each other are recognized from the results of the other survey.

• The Korean Journal of Cytopathology
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• v.4 no.1
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• pp.45-51
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• 1993

A 30-year-old woman who was diagnosed as peripheral neuroblastoma by fine needle aspiration of a soft mass of the right upper arm is described. She presented a slowly growing, soft mass of the right upper arm for 1 month. The right humerus revealed no abnormal finding on X-ray. Ultrasonogram of the right upper arm revealed a well demarcated, smooth marginated solid mass without invasion of adjacent structures. Fine needle aspiration was done under the impression of soft tissue tumor with undetermined biologic behavior. The aspirates were highly cellular and the tumor cells were dispersed both singly and in clusters of varying size. The clusters occasionally showed a central capillary core and rosette-like structures. The tumor cells were small in size and had a small to medium amount of cytoplasm. Some of them revealed slender cytoplasmic processes. The nuclei showed distinct nuclear membranes, finely clumped chromatin and small conspicuous nucleoli. Cellular pleomorphism or mitotic figure was not definite. These cytologic findings were interpreted as a malignant, non-lymphomatous small round cell tumor, most likely representing peripheral neuroblastoma or Ewing's sarcoma. Final diagnosis was confirmed by simple excision as peripheral neuroblastoma.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.39-44
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• 2014

IMS(IP Multi-Media Subsystem) base on the IP service platform which can offer multimedia as the voice, audio, video, and data is service platform. In 3G mobile communication in the early day, IMS had a suggestion for supporting to multimedia service in the 3GPP. But now It is broadly substituting in the IPTV, wire phone company and it is substituted in internet platform base on the soft-switch in currently. Especially nowadays, 4G LTE in a mobile communication company is rapidly growing in market. Therefore, in this study, we had designed to the main prosser that can admit to 1,000 user over and SIP gateway which can link the IMS 코어 that can link SIP Device which adopt the standard protocol on the SIP.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.115-115
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• 2015

Many efforts have been devoted on chemical modification of graphene layer to modulate its electrical properties. In the previous report, laser irradiation on the CYTOP (Amorphous Fluoropolymer) covered graphene layer induces chemical modification wherein carbon fluoride is formed on the graphene surface. This results in the insulating I-V characteristics, which have been attracting much research interests on it. However, the direct analytical evidence of the fluoride formation on graphene surface is not yet studied. In this work we investigated what happened on the CYTOP/graphene interface during photon irradiation using spatially resolved photoemission spectroscopy method. It is found that the soft x-ray (614 eV) induces desorption of fluoride atoms from the CYTOP and change di-fluoride form to mono-fluoride. As the photo-induced fluorine desorption is continue strong dipole field generated by initial di-fluoride forms is gradually decreased, resulting in the overall binding energy shift of the C 1s core levels. Both photo-modified CYTOP and CYTOP starts to desorb above $286^{\circ}C$ (~ 0.047 eV), which means that no strong chemical interaction between CYTOP and graphene is established.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.627-627
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• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.417-430
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• 2003

A new method was developed to prepare microcapsules involving hydrophobic components. A totally new "silicone-resin-polypeptide" was used as the wall materials. The polypeptide was made by hydrolysis of collagen and silk protein and so on, and that was combined with silicone. This microcapsule was easily prepared from silicone-resin-polypeptide in water solution. The ratio of encapsulation in the microcapsule was not only high level as 90％, which had never been reached, but also the particle size could be controlled to obtain very small size (average particle size: 2${\mu}{\textrm}{m}$). Moreover, these microcapsules were resistant to high shearing forces and were stable over a long time period. This stable microcapsule was not crushed in pressure with finger spreading, so the core materials hardly touch the skin directly. Application in cosmetics by using microcapsule involving UV absorbents (2-ethylhexy1-4-methoxycinnamate (OMC) and 4-tert-butyl-4' -methoxydibenzoyl-methane (BMDBM)) was examined. It was possible to apply organic UV absorbents in water-rich formulations without any surfactant by using this microcapsule. This formulation demonstrated a good moisturizing and soft skin feel. Therefore, the microcapsule was applied to hair care products. As a result, the sunscreen hair lotion with microcapsule was able to prevent from damaging and decoloring of hair color by UV rays. As just, it was suggested that this microcapsules were be widely applied in cosmetics.cosmetics.