• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.322-325
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• 2005

The shrinking critical dimensions of modern technology place a heavy requirement on optimizing feature shapes at the micro- and nano scale. In addition, the use of ion beams in the nano-scale world is greatly increased by technology development. Especially, Focused ion Beam (FIB) has a great potential to fabricate the device in nano-scale. Nevertheless, FIB has several limitations, surface swelling in low ion dose regime, precipitation of incident ions, and the re-deposition effect due to the sputtered atoms. In recent years, many approaches and research results show that the re-deposition effect is the most outstanding effect to overcome or reduce in fabrication of micro and nano devices. A 2D string based simulation software AMADEUS-2D $(\underline{A}dvanced\;\underline{M}odeling\;and\;\underline{D}esign\;\underline{E}nvironment\;for\;\underline{S}putter\;Processes)$ for ion milling and FIB direct fabrication has been developed. It is capable of simulating ion beam sputtering and re-deposition. In this paper, the 2D FIB simulation is demonstrated and the characteristics of ion beam induced direct fabrication is analyzed according to various parameters. Several examples, single pixel, multi scan box region, and re-deposited sidewall formation, are given.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.1
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• pp.158-168
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• 2010

Objective : Jeungson-Ojeok-Hwan Bijukbang(JOH) has been used to treat patients with tumor etc. In the theory of Korean medicine, JOH can treat Juk-Chui. JOH is known to have treat Juk-Chui. Juk-Chui is analogous to tumor. Methods : For these reasons, the present study was designed to investigate the effects of JOH on solid tumor in mice in terms of immune-potentiating and direct cytotoxic action of JOH in vitro and vivo study. The present author investigated thymocyte and splenocyte proliferation to confirm immune-potentiating activity of JOH and also investigated tumor/body weight ratio and survival rates in tumor bearing mice. Results : In this study, administration of JOH decreased tumor/body weight ratio significantly, and prolonged survival duration compared to non-treated control. In addition, treatment with JOH suppressed proliferation rate of Sarcoma 180 (S-180) cells significantly, and elevated proliferation rates of thymocytes isolated from normal mice. These results were co-related with in vivo study. Conclusion : these results suggest that JOH is useful to treat patient with solid tumor, because JOH has direct toxic action for tumor cell and immune-potentiating action for T cells. Further study will need to elucidate exact mechanisms related in anti-cancer action of JOH.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.581-593
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• 1990

A semi-solid alloy in which solid and liquid phase are co-existing is obtained by strirring of Al7075 molten metal. A semi-solid alloy is dependent on the corresponding temperature within the solid-liquid range, and the process parameters should be controlled accurately to obtain the homogeneous semi-solid alloy. The possibility o homogeneous fiber-reinforce aluminum alloy by addition of $Al_{2}$O$_{3}$ short fibers with vigorous agitation was investigated. The billet of composite materials was fabricated by squeeze casting, and homogeneous dipersion state of fibers in billet of fabricated metal matrix composites was observed. A slurry of semi-solid short fiber metal matrix composites is used in the direct rolling process, and this process showed the fabrication possibility of metal matrix composite sheets. The fabricated sheet was tested regarding vickers hardness, elongation and micro-structure. It has become clear that mashy state processing and working are very useful to obtain parts of composites material closed to near net shape.

• Journal of the Korean Ceramic Society
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• v.19 no.2
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• pp.109-114
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• 1982

Fluoro-phlogopite crystals (Mica) were synthesized by two different methods; firstly the crystal was crystallized from the melts, and secondly mica crystalline was obtained from the direct solid state reaction. Addition of $CaF_2$ in the mica batch revealed the lowering the solid state reaction temperature. SEM and XRD were employed to observe mica crystalline flakes and solid solution forms. As a starting raw material Pyrophyllite was used resulting in the formation of mica crystals.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.518-523
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• 1993

A computer program has been developed for analyzing the two-dimensional unsteady conservation equations for transport phenomena in the ool region of direct rolling with semi-solid metal in order to describe the velocity and temperature, and the solidification process of the semi-solid metal. The energy equations of cooling roll is solved simultaneously with semi-solid metal in order consider heat transfer through the cooling roll. The FDM(finite difference method) and FEM(finite element method) are used in region of pool and roll, respsctively, to reduce computing time and to improve accuracy of calculation. In the present study, influence of solid fraction and casting speed are investigated in a point of view of strip formability with semi-solid metal.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.5
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• pp.401-412
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• 2013

The paper is to study on the simulation of the micro/macroscale thermo-electrochemical model of a single cell of anode-supported SOFC with direct internal reforming. The coupled heat and mass transport, electrochemical and reforming reactions, and fluid flow were simultaneously simulated based on mass, energy, charge conservation. The micro/macroscale model first calculates the detailed electrochemical and direct internal reforming processes in porous electrodes based on the comprehensive microscale model and then solve the macroscale processes such as heat and mass transport, and fluid flow in SOFCs with assumption of fully-developed flow in gas channel. The simulation results evaluate the overall performance by analyzing distributions of mole fraction, current density, temperature and microstructural design in co/counter flow configurations.

• KIISE Transactions on Computing Practices
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• v.24 no.3
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• pp.129-137
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• 2018

NVMe(Non-Volatile Memory Express) SSD(Solid State Drive) is a high-performance storage that makes use of flash memory as a storage cell, PCIe as an interface and NVMe as a protocol on the interface. It supports multiple I/O queues which makes it feasible to process parallel-I/Os on multi-core environments and to provide higher bandwidth than SATA SSDs. Hence, NVMe SSD is considered as a next generation-storage for data-center and cloud computing system. However, in the virtualization system, the performance of NVMe SSD is not fully utilized due to the bottleneck of the software I/O stack. Especially, when it uses I/O stack of the hypervisor or the host operating system like Xen and KVM, I/O performance degrades seriously due to doubled-I/O stack between host and virtual machine. In this paper, we propose a new I/O engine, called Direct-AIO (Direct-Asynchronous I/O) engine, that can access NVMe SSD directly for I/O performance improvements on QEMU emulator. We develop our proposed I/O engine and analyze I/O performance differences between the existed I/O engine and Direct-AIO engine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.581-584
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• 2005

Ion beam processing is one of the key technologies to realize mastless and resistless sub 50nm nano fabrication. Unwanted effects, however, may occur since an energetic ion can interact with a target surface in various ways. Depending on the ion energy, the interaction can be swelling, deposition, sputtering, re-deposition, implantation, damage, backscattering and nuclear reaction. Sputtering is the fundamental mechanisms in ion beam induced direct patterning. Re-deposition and backscattering are unwanted mechanisms to avoid. Therefore understanding of ion beam-solid interaction should be advanced for further ion beam related research. In this paper we simulate some important interaction mechanisms between energetic incident ions and solid surfaces and the results are compared with experimental data. The simulation results are agreed well with experimental data.

• Journal of the Korean Ceramic Society
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• v.42 no.6 s.277
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• pp.425-431
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• 2005

Line Shaped Solid Oxide Fuel Cell (SOFC) with multilayered structure has been fabricated via direct-writing process. The cell is electrolyte of Ni-YSZ cermet anode, YSZ electrolyte and LSM cathode. They were processed into pastes for the direct writing process. Syringe filled with each electrode and electrolyte paste was loaded into the computer-controlled robe-dispensing machine and the paste was dispensed through cylindrical nozzle of 0.21 mm in diameter under the air pressure of 0.1 tow onto a moving plate with 1.22 mm/s. First of all, the anode paste was dispensed on the PSZ porous substrate, and then the electrolyte paste was dispensed. The anode/electrolyte and the PSZ substrate were co-fired at $1350^{\circ}C$ in air atmosphere for 3 h. The cathode layer was similarly dispensed and sintered at $1200^{\circ}C$ for 1 h. All the electrode/electrolyte lines were visually aligned during the direct writing process. The effective reaction area of fabricated SOFC was $0.03 cm^2$, and the thickness of anode, electrolyte and cathode was 20 $\mu$m, 15 $\mu$m, and 10 $\mu$m, respectively. The single line-shaped SOFC fabricated by direct-writing process exhibited OCV of 0.95 V and maximum power density of $0.35W/cm^2$ at $810^{\circ}C$.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.260-265
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• 2006

An experimental study on the catalytic reformer adopted in the auxiliary power unit system of solid oxide fuel cell was conducted. A 3-fluid nozzle, by which liquid fuel such as diesel, water and air are sprayed and uniformed mixed, was designed and used in this study. An electrically heated monolith inserted in the reformer was used for the vaporization of fuel and water in the transient state of reformer. The reformer uses the partial oxidizing reaction at the catalyst and the supply of water prevents the flame combustion in the spraying zone and lessens the deactivation of catalyst. The result showed that the reforming of liquid fuel can be started by the electrically heated monolith and the 3-fluid nozzle can give the uniform mixing of fuel, water and air. It was also found that the reformer fueled by n-hexadecane can make the reformate, at best, containing $H_2$ at 15.5% and CO at 11.5% that are used as fuel in the solid oxide fuel cell.