• Journal of Broadcast Engineering
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• v.23 no.2
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• pp.261-273
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• 2018

As progress on image processing, computer vision and display technologies aroused market's interests on generation and consumption of various types of media, interests on UWV media are also increasing. In context of consumption of UWV media, to effectively manage load of servers and resources of end terminal devices and provide user-derived services, technology which enables users to select and consume interested regions of media seems to be needed. Here, this paper proposes a method for description and transmission of spatial relationships among media, which composes UWV, by expanding MPEG-CI and Layout signaling to enable users' selective consumption of UWV media.

• Polymer(Korea)
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• v.31 no.2
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• pp.123-129
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• 2007

Toughening mechanisms and mechanical properties of three different polyolefin-based composite systems we studied using the tensile, Izod impact and double-notch lout-point-bending (DN-4PB) test, which is well known be an effective tool for probing the failure mechanism (s) around the subcritically propagated crack tip. Microscopy observations such as optical microscopy and transmission electron microscopy were carried out lot the test samples. A detailed investigation clearly shows that a variety of toughening mechanisms, i.e., shear yielding, craze, particle-matrix debonding, rubber particle cavitation, crack deflection and bifurcation, are observed around crack tip damage zone. These toughening mechanisms are responsible for the observed, improved fracture toughness. Based on this study, DN-4PB technique is sufficient to obtain the information needed to describe the fracture behavior of polyolefin-based composites as well as their corresponding toughening mechanisms.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.518-524
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• 2016

The thermal aging effects on mechanical properties and microstructures in China low-activation martensitic steel have been tested by aging at $550^{\circ}C$ for 2,000 hours, 4,000 hours, and 10,000 hours. The microstructure was analyzed by scanning and transmission electron microscopy. The results showed that the grain size and martensitic lath increased by about $4{\mu}m$ and $0.3{\mu}m$, respectively, after thermal exposure at $550^{\circ}C$ for 10,000 hours. MX type particles such as TaC precipitated on the matrix and Laves-phase was found on the martensitic lath boundary and grain boundary on aged specimens. The mechanical properties were investigated with tensile and Charpy impact tests. Tensile properties were not seriously affected by aging. Neither yield strength nor ultimate tensile strength changed significantly. However, the ductile-brittle transition temperature of China low-activation martensitic steel increased by $46^{\circ}C$ after aging for 10,000 hours due to precipitation and grain coarsening.

• Fire Science and Engineering
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• v.20 no.4 s.64
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• pp.72-76
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• 2006

Polymer/clay nanocomposites have generated considerable interests in the past decade because adding just tiny amount of clay to the polymer matrix could produce a dramatic enhancement in physical, thermal and mechanical properties. Smectite clays, such as montmorillonite (MMT), are of great industrial value because of their high aspect ratio, plate morphology, intercalative capacity, natural abundance and low cost. In this study, PE/MMT nanocomposites were directly prepared by melt intercalating PE and the modified clay. The nanostructure was verified by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their flame retardant properties were measured and discussed by limiting oxygen index (LOI), char yield and smoke mass concentration. And their thermal stabilities were measured by differential thermogravimetric (DTG) and thermogravimetric analysis (TGA). The PE/MMT nanocomposites proved more effective the conventional composites in reinforcement. Two functions in the thermal stability of the PE/MMT nanocomposite, one is the barrier effect to improve the thermal stability, and another is catalysis, leading to a decrease of the thermal stability. The flammability was greatly decreased due to the formation of the clay-enriched protective char during the combustion.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.20-42
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• 1998

The present study was designed to understand the basic principles of the laser system and to assess the optimal coditions of the Nd:YAG laser irradiation system in order to expand the use of the laser system in the dental field. The laser system used in this study was a pulsed-wave output type and the power level is 9 watts. The incisors of developing rats were irradiated with the laser system explained above for 0.5, 1, and 2 seconds giving energy density 71, 167, and 215 J/$cm^2$ respectively. The rats were sacrificed just after irradiation or 10 minutes and 10 days after irradiation. The specimens were examined with the stereoscope, light microscope and transmission electron microscope. The results are as follows: 1. The tissue removal efficiency (depth of the cavity formed) is increased with the energy density after Nd:YAG laser irradiation. 2. The carbonized area is increased with the energy density. Cracks and melted appearance are seen in all kinds of the energy densities. 3. The lacunae in the damaged alveolar bone by the laser irradiation were empty, while those in the newly formed bone were occupied with the osteocytes. The damaged alveolar bone was repaired by the osteoblasts and macrophages on the periphery of the bone matrix. 4. The damaged enamel was replaced by the loose connective tissues showing many kinds of cells. The ameloblasts were differntiated on the replaced loose connective tissue. 5. The damaged dentin was repaired by the irregular dentin formed by the odontoblasts differentiated from the mesenchymal cells migrated from the pulp core.

• Advances in nano research
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• v.4 no.1
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• pp.15-29
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• 2016

A low cost environmentally benign surface coating binder is highly desirable in the field of material science. In this report, castor oil based hyperbranched polyester/bitumen modified fly ash nanocomposites were fabricated to achieve the desired performance. The hyperbranched polyester resin was synthesized by a three-step one pot condensation reaction using monoglyceride of castor oil based carboxyl terminated pre-polymer and 2,2-bis (hydroxymethyl) propionic acid. Also, the bulk fly ash of paper industry waste was converted to hydrophilic nano fly ash by ultrasonication followed by transforming it to an organonano fly ash by the modification with bitumen. The synthesized polyester resin and its nanocomposites were characterized by different analytical and spectroscopic tools. The nanocomposite obtained in presence of 20 wt% styrene (with respect to polyester) was found to be more homogeneous and stable compared to nanocomposite without styrene. The performance in terms of tensile strength, impact resistance, scratch hardness, chemical resistance and thermal stability was found to be improved significantly after formation of nanocomposite compared to the pristine system after curing with bisphenol-A based epoxy and poly(amido amine). The overall results of transmission electron microscopic (TEM) analysis and performance showed good exfoliation of the nano fly ash in the polyester matrix. Thus the studied nanocomposites would open up a new avenue on development of low cost high performing surface coating materials.

• Journal of Korean Philosophical Society
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• no.122
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• pp.85-134
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• 2018

In this article, I will provide a philosophical discourse on digital sexual violence that is a technological version of male violence. First, critical analysis of the mechanism of the spatiality and the temporality of the hidden and illicit camera is developed to focus on the immeasurable damage of this violence. I elaborate a notional division between digital sexual violence and cyber sexual violence. Secondly, the ease of taking images of women's bodies and the rapid transmission of these images through the advancement of digital communication technology and hyperconnectivity, lead to use these images as a new digital monet for men. They consolidate their male solidarity by reaffirming female inferiority and humiliating women. Thirdly, the invention of the structure of the new affect to resist to digital sexual violence is crucial. For that, it would be necessary to pass from the sexual shame to the sexual displeasure and to the socio-political indignation. These would create another opportunity to resist to digital sexual violence.

• Metals and materials international
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• v.24 no.6
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• pp.1359-1368
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• 2018

The mechanical properties and microstructure evolution of Mg-8Li-3Al-1Y alloy undergoing different rolling processes were systematically investigated. X-ray diffraction, optical microscope, scanning electron microscopy, transmission electron microscopy as well as electron backscattered diffraction were used for tracking the microstructure evolution. Tensile testing was employed to characterize the mechanical properties. After hot rolling, the $MgLi_2Al$ precipitated in ${\beta}-Li$ matrix due to the transformation reaction: ${\beta}-Li{\rightarrow}{\beta}-Li+MgLi_2Al+{\alpha}-Mg$. As for the alloy subjected to annealed hot rolling, ${\beta}-Li$ phase was clearly recrystallized while recrystallization rarely occurred in ${\alpha}-Mg$ phase. With regard to the microstructure undergoing cold rolling, plenty of dislocations and dislocation walls were easily observed. In addition, the microstructure of alloys subjected to annealed cold rolling revealed the formation of new fresh ${\alpha}-Mg$ grains in ${\beta}-Li$ phase due to the precipitation reaction. The mechanical properties and fracture modes of Mg-8Li-3Al-1Y alloys can be effectively tuned by different rolling processes.

• Metals and materials international
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• v.24 no.6
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• pp.1394-1402
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• 2018

This study investigates the mechanism of MnS precipitation on $Al_2O_3-SiO_2$ inclusions during the solidification of non-oriented silicon steel, especially the influence of the phase structures and sizes of the oxides on the MnS precipitation, by scanning electron microscopy and transmission electron microscopy coupled with energy dispersive spectrometry. The investigation results show that MnS tends to nucleate on submicron-sized $Al_2O_3-SiO_2$ inclusions formed by interdendritic segregation and that it covers the oxides completely. In addition, MnS can precipitate on micron-sized oxides and its precipitation behavior is governed by the phase structure of the oxides. The MnS embryo formed in a MnO-containing oxide can act as a substrate for MnS precipitation, thus permitting further growth via diffusion of solute atoms from the matrix. MnS also precipitates in a MnO-free oxide by the heterogeneous nucleation mechanism. Furthermore, MnS is less prone to precipitation in the $Al_2O_3$-rich regions of the $Al_2O_3-SiO_2$ inclusions; this can be explained by the high lattice disregistry between MnS and $Al_2O_3$.

• Metals and materials international
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• v.24 no.6
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• pp.1193-1201
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• 2018

Dilatometry is a useful technique to obtain experimental data concerning transformation. In this paper, a dilation conversional model was established to calculate carbides fraction in AISI H13 hot-work tool steel based on the measured length changes. After carbides precipitation, the alloy contents in the matrix changed. In the usual models, the content of carbon atoms after precipitation is considered as the only element that affects the lattice constant and the content of the alloy elements such as Cr, Mo, Mn, V are often ignored. In the model introduced in this paper, the alloying elements (Cr, Mo, Mn, V) changes caused by carbides precipitation are incorporated. The carbides were identified using scanning electron microscope and transmission electron microscope. The relationship between lattice constant of carbides and temperature are measured by high-temperature X-ray diffraction. The results indicate that the carbides observed in all specimens cooled at different rates are V-rich MC and Cr-rich $M_{23}C_6$, and most of them are V-rich MC, only very few are Cr-rich $M_{23}C_6$. The model including the effects of substitutional alloying elements shows a good improvement on carbides fraction predictions. In addition, lower cooling rate advances the carbides precipitation for AISI H13 specimens. The results between experiments and mathematical model agree well.