• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.29 no.2
• /
• pp.45-49
• /
• 2019

Relatively fine silicon carbide (SiC) crystalline aggregates have been synthesized with the carbonized rice husks, paper sludge, coffee grounds as the carbon sources and the silica powder. The main reaction source to obtain silicon carbide (SiC) aggregates from the mixture of carbon sources and silica was inferred as the gaseous silicon monoxide (SiO) phase, being created from this mixture through the carbothermal reduction reaction. The silicon carbide (SiC) crystalline aggregates, fabricated from the carbonized rice husks and paper sludge, coffee grounds and silica ($SiO_2$) powder, were investigated by XRD patterns, FE-SEM and FE-TEM images. In these specimens, obtained from the carbonized rice husks, paper sludge and silica, XRD patterns showed rather high strong peak of (111) plane near $35^{\circ}$. The FE-TEM images and patterns of specimens, synthesized from carbonized rice husks, paper sludge, coffee grounds and silica under Ar atmosphere, showed relatively fine particles under $1{\mu}m$ and crystalline peak (110) of silicon carbide (SiC) diffraction pattern.

• International Journal of Computer Science & Network Security
• /
• v.22 no.5
• /
• pp.39-48
• /
• 2022

The main purpose of the work is to analyze modern innovative educational practices in the field of culture and art and their effectiveness in the context of the spread of digitalization trends. The study used general scientific theoretical methods of analysis, synthesis, analogy, comparative, induction, deduction, reductionism, and a number of others, allowing you to fully understand the pattern of modern modernization processes in a long historical development and demonstrate how the rejection of the negativity of progress allows talented artists to realize their own potential. The study established the advantages and disadvantages of involving innovative technologies in the educational process on the example of European experience and outlined possible ways of implementing digitalization processes in Ukrainian institutions of higher education, formulated the main difficulties encountered by teachers and students in the use of technological innovation in the pandemic. The rapid development of digital technologies has had a great impact on the sphere of culture and art, both visual, scenic, and musical in all processes: creation, reproduction, perception, learning, etc. In the field of art education, there is a synthesis of creative practices with digital technologies. In terms of music education, these processes at the present stage are provided with digital tools of specially developed software (music programs for composition and typing of musical text, recording, and correction of sound, for quality listening to the whole work or its fragments) for training programs used in institutional education and non-institutional learning as a means of independent mastering of the theory and practice of music-making, as well as other programs and technical tools without which contemporary art cannot be imagined. In modern stage education, the involvement of video technologies, means of remote communication, allowing realtime adjustment of the educational process, is actualized. In the sphere of fine arts, there is a transformation of communicative forms of interaction between the teacher and students, which in the conditions of the pandemic are of two-way communication with the help of information and communication technologies. At this stage, there is an intensification of transformation processes in the educational industry in the areas of culture and art.

• Conservation Science in Museum
• /
• v.29
• /
• pp.153-162
• /
• 2023

Clay figure of Baekje, produced by forming and molding various shapes using clay, are mainly excavated from temple sites and provide essential information for studying the Buddhist art of Baekje. Research on clay figures of Baekje primarily focuses on the characteristics of Baekje-era temples in which such figures are excavated, as well as the role and production techniques of clay figures, by comparing regional and morphological characteristics. In particular, research on the manufacturing method of clay figures is mainly carried out by visual observation, whereas precise scientific analysis is required to understand production techniques and characteristics of raw materials in greater detail. In this study, to confirm such production techniques and material characteristics, computed tomography (CT) scans were conducted on the Clay Bodhisattva excavated from the Neungsan-ri Temple site in Buyeo. As a result, it was found that the Clay Bodhisattva was made using a cylindrical core of fine clay, tied together with several thin branches or reeds with straws. The clay used in the figure bore traces indicating the presence of herbaceous plants, which increase adhesion between clay and prevent cracks in the contraction process. On the other hand, the density of the fine clay differs on the inside and outside of the clay figure. Based on this, it is presumed that the clay was applied around the cylindrical core to shape the Clay Bodhisattva. The clay was reapplied on top of the figure to express the detailed shape and pattern.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.21 no.6
• /
• pp.444-452
• /
• 2009

Textural parameters were calculated from the surface sediments collected from Jinu-do beach in Nov. 2005 and May 2006. In Nov. 2005 and May, 2006, the grain size distribution of surface sediments shows that the mode of $3.0\phi$(i.e., 0.125 mm) dominated the west beach of Jinu-do, but in the east beach the mode of $3.0\phi$(i.e., 0.125 mm) decreased and the mode of $2.5\phi$(i.e., 0.177 mm) was apparently distinct, resulting in the more coarsening trend. Mean grain size of surface sediments also indicates little difference in the west beach between two investigations, but the increasing difference between mean grain sizes in the east beach, showing more coarsening pattern. Such seasonal pattern corresponds to the positive skewness in the east beach in May, 2006. As a result, after the winter in 2005, the surface sediments in the west beach of Jinu-do experienced a little variation, whereas the apparent coarsening of surface sediments occurred in the east beach by removal of $3.0\phi$(i.e., 0.125 mm) fine-grained sand particles. The observed seasonal change may be attributed to the different hydrographic condition and sediment delivery/removal on the surface sediments between the west beach and the east beach of Jinu-do through the increased precipitation and more freshwater discharge from the Nakdong River during the summer and the intensified wave and tide during the winter in the Nakdong River estuary.

• Journal of the korean society of oceanography
• /
• v.39 no.1
• /
• pp.57-71
• /
• 2004

Based on the data obtained under the China-Korea joint project (1997-2001) and historic observations, the distribution, transportation and sedimentation of sediment in the southern Yellow Sea (SYS) are discussed, and the controversial formation mechanism of muddy sediments is also explored. The sediment transport trend analysis indicates that the net transport direction of sediment in the central SYS (a fine-grained sediment deposited area) points to $123.4^{\circ}E,\;35.1^{\circ}N$, which is a possible sedimentation center in the central SYS. The sediment transport pattern is verified by the distribution of total suspended matter (TSM) concentration and ${\delta}^{13}C$ values of particulate organic carbon (POC), the latter indicates that the bottom water plays a more important role than the surface water in transporting the terrigenous material to the central deep-water area of the SYS, and the Yellow Sea circulation is an important control factor for the sediment transport pattern in the SYS. The carbon isotope signals of organic matter in sediments indicate that the Shandong subaqueous delta has high sedimentation rate and the deposited sediments originate mainly from the modern Yellow River. The terrigenous sediments in deep-water area of the SYS originate mainly from the old Yellow River and the modern Yellow River, and only a small portion originates from the modern Yangtze River. The analytical results of TSM and stable carbon isotopes are further confirmed by another independent tracer of sediment source, polycyclic aromatic hydrocarbons (PAHs). Five light mineral provinces in the SYS can be identified and they indicate inhomogeneity in sources and sedimentary environment. The modern shelf sedimentary processes in the SYS are controlled by shelf dynamic factors. The muddy depositional systems are produced in the shelf low-energy environments, which are controlled by some meso-scale cyclonic eddies (cold eddies) in the central SYS and the area southwest of the Cheju Island. On the contrary, an anticyclonic muddy depositional system (warm eddy sediment) appears in the southeast of the SYS (the area northwest of the Cheju Island). In this study, we give the cyclonic and anticyclonic eddy sedimentation patterns.

• Journal of the Mineralogical Society of Korea
• /
• v.20 no.3
• /
• pp.203-212
• /
• 2007

Mineral compositions of 89 Yellow Sea surface sediments collected at the second cruise in 2001, were determined using the high resolution X-ray diffractometer and Siroquant v.3.0 program. Yellow Sea surface sediments are composed of major minerals (quartz 57.8%, plagioclase 16.0% and alkali feldspar 10.0%), clay minerals, and calcite. Illite (8.7%) is the most abundant clay mineral, chlorite (2.6%) is the second, and kaolinite (0.6%) is few. however smectite is not detected. Quartz content is very high around the margin of the Yellow Sea, however is very low along the northwest to southeast direction extending from southeast of Sandong Peninsula to southwest of Jeju Island. It has similar distribution pattern with that of coarse sediment (sand). The coarse sediment, is mainly consisted of quartz, may be much supplied from the eastern part and southwestern part of the Yellow Sea. Illite distribution pattern is opposite to that of quartz. It is similar to those of clay and mud particles, therefore it can be suggested that fine sediment may be largely supplied from the northwestern part of the Yellow Sea. It is necessary to continue this kind of investigation, because it is difficult to interpret the sediment provenance of the Yellow Sea only from the result of this study.

• The Journal of Korean Academy of Prosthodontics
• /
• v.30 no.2
• /
• pp.259-271
• /
• 1992

This study was designed to investigate the criteria of the perfect smile that was necessary to improve the esthetic problem in oral and maxillo-facial region and treating the anterior tooth region. The author took the facial straight photograph of 240 university students(male : 129, female : 111) in a resting and a smiling position, measured and analized the lip pattern and the relation between the lip and the teeth when they were smiling. Besides, 10 members of committee for appraisal (dentist : 5 persons, professor of the college of fine arts : 5 persons) estimated the smiling pattern. After that the author have compared and analyzed the obtained results. The results obtained were as follows : 1. In the shape of the upper lip, when the upper lip curved downward, it was 42.92% , straight was 45.00% and curved upward was 12.08%. The group in which the upper lip curved upward was the most esthetic. 2. In the relation between the upper lip and the teeth, high smile was 29.17%, average smile was 55.83% and low smile was 15.00%. The group of average smile was the most esthetic. 3. In the parallel relation between the lower lip and maxillary anterior incisal curvature, the group of paralled was 60.42%, the group of straight was 34.17% and the group of reverse was 5.41%. The group of parallel was the most esthetic. 4. In the relationship between maxillary anterior incisor and lower lip, the group of the maxillary anterior incisor were slightly covered by the lower lip was 10.42%, the group of the maxillary anterior teeth touched to the lower lip was 35.83%, and the no-touching was 53.75%. The group of the maxillary anterior teeth touched to the lower lip was the most esthetic. 5. In the teeth displayed in a smile, displayed to the canine was 0.84%, displayed to the first premolar was 19.17%, displayed to the second premolar was 57.92%, displayed to the first molar was 20.00% and displayed to the second molar was 2.08%. The group of displayed to the first molar was the most esthetic. 6. At smiles, the width of the mouth corner was 0.46 times of the full face width, 0.95 times of the interpupillary distance, and 1.23 times of the resting position. 7. At smiles, the lengh of the upper lip was 0.71 times and lower lip was 0.93 times of the length in the resting position.

• Journal of the Korean Magnetics Society
• /
• v.4 no.2
• /
• pp.173-178
• /
• 1994

The water-based magnetic fluids were prepared with the synthesized ultra-fine magnetite, oleic acid and SDBS (sodium dodecyl benzene sulfonate) as surfactants. The dispersion of water-based magnetic fluids was about 90 % when the added amounts of oleic acid and SDBS for magnetite(27 g) were more than $2.66{\times}10^{-3}$ mol and 10 g respectively. As the solid content increased from o. 05 g/cc to 0.4 g/cc, saturation magnetization of magnetic fluids at 5 kOe increased from 1.98 emu/g to 9.63 emu/g at $Fe^{2+}/Fe^{3+}=0.5$ and from 2.7 emu/g to 14.63 emu/g at $Fe^{2+}/Fe^{3+}=1.0$, and the its viscosity increased from 1.3 cp to 4.4 cp at $Fe^{2+}/Fe^{3+}=0.5$. pH region of oleic acid and SDBS stabilized water-based mag¬netic fluids was stable was in the range of pH 3.0 to pH 11.0. Stability of Water-based magnetic fluids can be obtained by observation of magnetic memory patterns on the VCR tape.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.363-363
• /
• 2008

The development of dry etching process for sapphire wafer with plasma has been key issues for the opto-electric devices. The challenges are increasing control and obtaining low plasma induced-damage because an unwanted scattering of radiation is caused by the spatial disorder of pattern and variation of surface roughness. The plasma-induced damages during plasma etching process can be classified as impurity contamination of residual etch products or bonding disruption in lattice due to charged particle bombardment. Therefor, fine pattern technology with low damaged etching process and high etch rate are urgently needed. Until now, there are a lot of reports on the etching of sapphire wafer with using $Cl_2$/Ar, $BCl_3$/Ar, HBr/Ar and so on [1]. However, the etch behavior of sapphire wafer have investigated with variation of only one parameter while other parameters are fixed. In this study, we investigated the effect of pressure and other parameters on the etch rate and the selectivity. We selected $BCl_3$ as an etch ant because $BCl_3$ plasmas are widely used in etching process of oxide materials. In plasma, the $BCl_3$ molecule can be dissociated into B radical, $B^+$ ion, Cl radical and $Cl^+$ ion. However, the $BCl_3$ molecule can be dissociated into B radical or $B^+$ ion easier than Cl radical or $Cl^+$ ion. First, we evaluated the etch behaviors of sapphire wafer in $BCl_3$/additive gases (Ar, $N_2,Cl_2$) gases. The behavior of etch rate of sapphire substrate was monitored as a function of additive gas ratio to $BCl_3$ based plasma, total flow rate, r.f. power, d.c. bias under different pressures of 5 mTorr, 10 mTorr, 20 mTorr and 30 mTorr. The etch rates of sapphire wafer, $SiO_2$ and PR were measured with using alpha step surface profiler. In order to understand the changes of radicals, volume density of Cl, B radical and BCl molecule were investigated with optical emission spectroscopy (OES). The chemical states of $Al_2O_3$ thin films were studied with energy dispersive X-ray (EDX) and depth profile anlysis of auger electron spectroscopy (AES). The enhancement of sapphire substrate can be explained by the reactive ion etching mechanism with the competition of the formation of volatile $AlCl_3$, $Al_2Cl_6$ or $BOCl_3$ and the sputter effect by energetic ions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.9
• /
• pp.652-661
• /
• 2020

Recently, the Korean government developed the RE3020 (renewable energy) policy to overcome environmental problems, such as fine dust, climate change, and large-scale PV systems interconnected with a distribution system. When a large-scale PV system is interconnected in the distribution system, however, a malfunction can occur, and the protection devices may not be operated because of the dividing effect depending on the magnitude and direction of fault current as well as connection types and location of the PV system. Therefore, this paper proposes a search algorithm for the malfunction pattern of protection devices based on various scenarios, when large-scale PV systems are operated and interconnected in a distribution system. This paper presents a malfunction mechanism of protection devices according to the installation locations of recloser (R/C). Furthermore, the modeling of a distribution system with large-scale PV systems was performed using Off-DAS S/W, and the malfunction patterns of protection devices were analyzed based on a range of scenarios. From the simulation results with the proposed model and algorithm for searching for protection devices, it was confirmed that they are useful and effective in identifying a malfunction phenomenon depending on the installation location of the R/C and connection type of PV system.