• Journal of the korean Society of Automotive Engineers
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• v.5 no.4
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• pp.47-61
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• 1983

In this paper the simulation of a thermodynamic power cycle for a 4-stroke, single-cylinder, spark-ignition engine was studied. In this simulation the cylinder volume was restricted to two zones, a burnt and an unburnt zone, and the convective heat transfer from cylinder contents to surroundings was considered. The chemical species in burnt gas considered was 12 species including H$_{2}$O, H$_{2}$, OH, H, N$_{2}$, NO, N, CO$_{2}$, CO, $O_{2}$, O and Ar. Using this model, computer program for compression, ignition and expansion processes was composed and pressure, temperature and composition of cylinder gas at each crank angle were computed. The composition of CO$_{2}$, CO, $O_{2}$ in the burnt gas when exhaust valve opens, the maximum temperature, the maximum flame speed and the combustion duration were also computed as a function of equivalence ratio. The relation between burnt mass fraction and burnt volume fraction was also computed.

• Journal of the Korean Vacuum Society
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• v.4 no.S2
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• pp.49-57
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• 1995

At present the processes of boronizing have been mostly studied in a plasma from gaseous compounds containing the impregnating element and are in an industrial use. These have been investigated by a variety of works in a glow discharge with different mixture ratios of $B_2H_6$ and $H_2$ as well as $BCl_3$ and $H_2$. The active atomosphere has been diluted by Ar or some other inert gas in order to enhance control of boron potential and to reduce the ignition voltage of the glow discharge. The Control of gaseous atomosphere is essential to a boride layer in plamsa boronizing treatment. The boride formation is required to make the workpiece surface saturated with boron content. The present study considers the efficiency of plasma boronizing reactions and the morphology of boride layer under various plasma conditions

• Bulletin of the Korean Chemical Society
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• v.15 no.1
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• pp.28-33
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• 1994

The laser-assisted chemical vapor deposition (LCVD) is described, by which the growth of single-phase GaN epitaxy is achieved at lower temperatures. Trimethylgallium (TMG) and ammonia are used as source gases to deposit the epitaxial films of GaN under the irradiation of ArF excimer laser (193 nm). The as-grown deposits are obtained on c-face sapphire surface near 700$^{\circ}$C, which is substantially reduced, relative to the temperatures in conventional thermolytic processes. To overcome the lattice mismatch between c-face sapphire and GaN ad-layer, aluminum nitride(AlN) is predeposited as buffer layer prior to the deposition of GaN. The gas phase interaction is monitored by means of quadrupole mass analyzer (QMA). The stoichiometric deposition is ascertained by X-ray photoelectron spectroscopy (XPS). The GaN deposits thus obtained are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and van der Pauw method.

• Journal of The Korean Astronomical Society
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• v.52 no.4
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• pp.89-97
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• 2019

We demonstrate the subsurface origin of the observed evolution of the solar active region 10930 (AR10930) associated with merging and breakup of magnetic polarity regions at the solar surface. We performed a magnetohydrodynamic simulation of an emerging magnetic flux tube whose field-line twist is asymmetrically distributed along its axis, which is a key to merging and fragmentation in this active region. While emerging into the surface, the flux tube is subjected to partial splitting of its weakly twisted portion, forming separate polarity regions at the solar surface. As emergence proceeds, these separate polarity regions start to merge and then break up, while in the corona sigmoidal structures form and a solar eruption occurs. We discuss what physical processes could be involved in the characteristic evolution of an active region magnetic field that leads to the formation of a sunspot surrounded by satellite polarity regions.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.90-95
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• 2023

With the rapid development of deep learning and artificial intelligence, generative models have achieved remarkable success in the field of image generation. By combining the stable diffusion method with Web UI technology, a novel solution is provided for the application of AI painting generation. The application prospects of this technology are very broad and can be applied to multiple fields, such as digital art, concept design, game development, and more. Furthermore, the platform based on Web UI facilitates user operations, making the technology more easily applicable to practical scenarios. This paper introduces the basic principles of Stable Diffusion Web UI technology. This technique utilizes the stability of diffusion processes to improve the output quality of generative models. By gradually introducing noise during the generation process, the model can generate smoother and more coherent images. Additionally, the analysis of different model types and applications within Stable Diffusion Web UI provides creators with a more comprehensive understanding, offering valuable insights for fields such as artistic creation and design.

• Journal of the Korea Society for Simulation
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• v.22 no.4
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• pp.57-66
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• 2013

The needs for reusable 3D visualization tool has been being raised in various industries. Especially in the defense modeling and simulation (M&S) domain, there are abundant researches about reusable and interoperable visualization system, since it has a critical role to the efficient decision making by offering diverse validation and analyzing processes. To facilitate the effectiveness, states-of-the-arts M&S systems are applying VR (Virtual Reality) or AR (Augmented Reality) technologies. To reduce the work burden authors design a collaborative visualization environment based on a commercial game engine Unity3D. We define the requirements of the warfare simulation by analyzing pros and cons of existing tools and engines such as SIMDIS or Vega, and apply functionalities of the commercial game engine to satisfy the requirements. A prototype has been implemented as the collaborative visualization environment of iCAVE at KAIST, which is a facility for immersive virtual environment. The facility is intraoperative with smart devices.

• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.191-196
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• 2001

Biodegradable polymeric microspheres were studied for their usefulness as carriers for the delivery of vaccine antigens. However, protein antigen could be denatured during microencapsulation processes due to the exposure to the organic phase and stress condition of cavitation and shear force. Therefore this study was carried out to re-evaluate the degree of protein denaturation during microencapsulation with poly(lactide-co-glycolide) (PLGA) copolymer. PLGA microspheres containing ovalbumin (OVA), prepared by W/O/W multiple emulsification method, were suspended in pH 7.4 PBS and incubated with shaking at $37.5^{\circ}C$. Drug released medium was collected periodically and analyzed for protein contents by micro-BCA protein assay. In order to evaluate the protein integrity, release medium was subjected to the analyses of SDS-PAGE and size exclusion chromatography (SEC). And enzyme-linked immunosorbent assay (ELISA) was introduced to measure the immunoreactivity of entrapped OVA and to get an insight into the three-dimensional structure of epitope. The structures of entrapped protein were not affected significantly by the results of SDS-PAGE and SEC. However, immunoreactivity of released antigen was varied, revealing the possibility of protein denaturation in some microspheres when it was evaluate by ELISA method. Therefore, in order to express the degree of protein denaturation, antigenicity ratio (AR) was obtained as follows: amount of immunoreactivity of OVA/total amount of OVA released ${\times}100(%)$. ELISA method was an efficient tool to detect a protein denaturation during microencapsulation and the comparison of AR values resulted in more accurate evaluation for immunoreactivity of entrapped protein.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.746-752
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• 2015

This study investigates the effects of aspect ratio (transport length-to-width) on diffusive-convection for physical vapor transport processes of $Hg_2Cl_2-NO$ system. For a system with the temperature difference of 20 K between an interface at the source material region and growing crystal interface, the linear temperature profiles at walls, the total molar fluxes at Ar = 2 are much greater than Ar = 5 as well as the corresponding nonuniformities in interfacial distributions due to the effect of convection. The maximum total molar flux at the gravitational acceleration of 1 $g_0$ is greater twice than at the level of 0.1 $g_0$, where g0 denotes the gravitational acceleration on earth. With increasing aspect ratio from 2 to 5, a diffusive-convection mode is transited into the diffusion mode, and then the strength of diffusion is predominant over the strength of diffusive-convection.

• Ocean and Polar Research
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• v.27 no.2
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• pp.205-214
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• 2005

From ancient Antarctic glacier ice, we extracted total genomic DNA that was suitable for prokaryotic 16S rDNA gene cloning and sequencing, and bacterial artificial chromosome (BAC) library and end-sequencing. The ice samples were from the Dry Valley region. Age dating by $^{40}Ar/^{39}Ar$ analysis on the volcanic ashes deposited in situ indicated the ice samples are minimum 100,000-300,000 yr (sample DLE) and 8 million years (sample EME) old. Further assay proved the ice survived freeze-thaw cycles or other re-working processes. EME, which was from a small lobe of the basal Taylor glacier, is the oldest known ice on Earth. Microorganisms, preserved frozen in glacier ice and isolated from the rest of the world over a geological time scale, can provide valuable data or insight for the diversity, distribution, survival strategy, and evolutionary relationships to the extant relatives. From the 16S gene cloning study, we detected no PCR amplicons with Archaea-specific primers, however we found many phylotypes belonging to Bacteria divisions, such as Actinobacteria, Acidobacteria, Proteobacteria $({\alpha},\;{\beta},\;and\;{\gamma})$, Firmicutes, and Cytophaga-Flavobacterium-Bacteroid$. BAC cloning and sequencing revealed protein codings highly identical to phenylacetic acid degradation protein paaA, chromosome segregation ATPases, or cold shock protein B of present day bacteria. Throughput sequencing of the BAC clones is underway. Viable and culturable cells were recovered from the DLE sample, and characterized by their 16S rDNA sequences. Further investigation on the survivorship and functional genes from the past should help unveil the evolution of life on Earth, or elsewhere, if any.

• Journal of the Korean Chemical Society
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• v.20 no.2
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• pp.97-110
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• 1976

Effects of direct multiple quantum excitations in vibrational energy transfer were investigated. Vibrational transition probabilities for 0${\rightarrow}$2, 0${\rightarrow}$3, and 0${\rightarrow}$4 excitations were explicitly formulated including both direct 0→n excitations and stepwise single quantum processes. For the formulation the perturbing force was derived from the exponential potential including terms up to fourth order in the vibrational amplitude. The head-on collinear collision model between a harmonic oscillator and an incident particle was employed, and the formulation was based on the semiclassical approximation. Numerical results were obtained for five different collision systems (Ar${\cdots}$O-N, He${\cdots}$H-H, He${\cdots}$H-Cl, 5${\cdots}$1-2, 2${\cdots}$12-12). Comparison between the present results and those obtained using the linearized interaction potential showed that the overall effect of including the direct multiple quantum transition is to decrease the probabilities at low collision energies and to increase them at high energies. The present results were found to be significantly different from those obtained using the linearized potential for collision systems He${\cdots}$H-H, He${\cdots}$H-Cl, and 5${\cdots}$1-2. For systems Ar${\cdots}$O-N and 2${\cdots}$12-12 the differences were negligible.