• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.338.2-338.2
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• 2016

Al doped ZnO (AZO) thin films were deposited on Si substrates with rod-shaped-surface by pulsed laser deposition method (PLD). Si-rods were prepared through chemical etching. To analyze the influence on the formation of the rod structure, samples with various chemical etching conditions such as AgNO3/HF ratio, etching time, and solution temperature were prepared. The morphology of Si-rod structures were examined by FE-SEM. Fig. 1 shows a typical structure of n-AZO/p-Si-rod juncions. The fabricated n-AZO/p-Si-rod devices exhibited p-n diode current-voltage characteristics. We compared the I-V characteristics of n-AZO/p-Si-rod devices with the samples without Si-rod structure.

• Journal of the Korean Ceramic Society
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• v.34 no.12
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• pp.1240-1246
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• 1997

Silicon carbides with self-reinforced microstructure which hore a small grain matrix and dispersed large grains with rod-like type were prepared by the liquid-phase sintering and the control of starting phases of raw materials. The specimens with self-reinforced microstructure could be obtained from the compacts with mixed compositions of $\alpha$-SiC and 10-50 % $\beta$-SiC powders and by the pressureless sintering at 185$0^{\circ}C$ for 5h. Large grains with rod or plate-like types were 4H-SiC and small grains with equi-axed type were 6H-SiC. Fracture grains with rod or plate-like types were 4h-SiC and small grains with equi-axed type were 6H-SiC. Fracture toughness of specimens with self-reinforced microstructure was increased by the crack deflection and formation of microcracking due to the existence of rod-like large grains during crack propagation.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1615-1620
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• 2003

The purpose of the study is not only to establish experimental system for laser chemical vapor deposition but also to find the characteristics of SiC rod growth that is the beginning step in developing technology of 3 dimensional prototyping with laser chemical vapor deposition. In this study, SiC rod was generated with varying TMS pressure for 5 minutes. Deposition rates with varying TMS pressure, shapes of rods, surface roughness and component organization were investigated, in particular.

• Resources Recycling
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• v.12 no.3
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• pp.25-30
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• 2003

The synthesis of SiC used for the parts of the gas turbine and the heat exchanger, was carried out. In this study, wire cutting slurry of silicon wafer and the graphite rod of spent zinc-carbon battery were applied to the starting materials for the synthesis. The powders of Si or Si+SiC were obtained from the waste material by filtration, gravity separation and magnetic separation. Graphite powder was produced by dismantling, grinding and gravity separation from spent zinc-carbon battery. The synthesis of SiC could be completed from the mixture powders of Si and C or Si+SiC and C at the condition of equivalent ratio of Si and C, atmosphere of Ar or vacuum, temperature of above 1$600^{\circ}C$ and 2 hours reactions. The purity of synthesized Si-C was above 99%.

• Journal of Korea Foundry Society
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• v.13 no.6
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• pp.532-539
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• 1993

The effect of casting variables for making pure Al and Al-5wt%Si alloy rods free from any surface and inside defects was studied by adopting the horizontal continuous casting method with heated mold. The rods were cast under the casting conditions such as the mold temperature of $670{\sim}690^{\circ}C$, water flow rate of $0.2{\sim}0.6{\ell}/min$, and rod diameter of $4{\sim}8mm$, when the melt temperature and mold to cooler distance was fixed at $700^{\circ}C$ and 20mm, respectively. The results represented that the casting speed for good quality rod increased as the water flow rate increased, whereas, the casting speed decreased as the rod diameter or mold temperature increased. The statistical analysis of $2^3$ factorial design was also applied and the results represented that the averaged optimum casting speed for pure Al(302mm/min) was higher than that of Al-5wt%Si alloy(273mm/min) resulting from the difference of superheat applied. The effect of rod diameter on the optimum casting speed was the highest for pure Al as well as Al-5wt%Si alloy. The effect of water flow rate and mold temperature on the optimum casting speed was in decreasing order.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.3
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• pp.122-135
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• 2014

This paper was studied on the horizontal continuous casting of Al-xSi(x=10~15%) aluminum alloy. The experiments of the horizontal continuous casting was carried out by the horizontal continuous casting machine for various casting conditions and investigated on fracture types and mechanisms. Surface defect types for the horizontal continuous casting is also investigated. And the study was carried out that the horizontal continuous casting conditions such as casting temperature, cooling rate, and drawing speed affect the hardness and primary silicon size of Al-xSi(x=10~15%) aluminum rod bar. Casting temperature within this experiment conditions don't affect on the hardness of rod bar but the higher casting temperature is the smaller primary silicon size. The higher cooling rate and drawing speed have the higher hardness and the smaller primary silicon size.

• Laser Solutions
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• v.9 no.2
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• pp.23-30
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• 2006

Silicon Nitride $(Si_3N_4)$, which is widely used in a variety of applications, is hard-to-machine due to its high hardness. At high temperature (e.g. above $1000^{\circ}C)$, however, the machinability can be greatly improved. In this work, we used a $CO_2$ laser with a high absorptivity to $Si_3N_4$ of 0.9 to locally heat the surface of a rotating $Si_3N_4$ rod on a lathe. In order to examine the effects of the laser-assisted heating on hardness, an $Si_3N_4$ rod is heated to temperatures from 900 to $1800^{\circ}C$ and is rotated at speeds from 440-900 rpm in experiments. When the rod is naturally cooled to room temperature, we measured the Vickers hardness (Hv); and observed the surface of HAZ using a scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) was used for ingredient analysis. Results showed that when heated at $1600^{\circ}C$, the hardness of $Si_3N_4$ decreased from 1500 Hv to 1000 Hv. Also, in order to predict the depth of HAZ, we numerically analyzed the laser-assisted heating of $Si_3N_4$.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.66-71
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• 2008

Alumium alloys hot forging process are gaining increased acceptance in the automotive and electronic industries and hot forging is one of the most efficient manufacturing method for mass product parts. It has been investigated the microstructures and mechanical properties of Al-11.7Si-0.5Mg (KNT40-T6)alloy fabricated by hot forging process for development of connecting rod in this study. The microstructure of hot forged specimen was composed of eutectic structure of alumimum solid solution and $Mg_2Si$ precipitates. The tensile strength of solutionized Al-11.7Si-0.5Mg alloy was 217MPa. This alloy showed a good corrosion resistance using electrochemical polarization test.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.481-488
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• 2004

Laser chemical vapor deposition can be used as a new approach for a rapid prototyping technique. The purpose of the study is to fabricate several 3-dimensional objects that are relatively simple as well as to find the characteristics of SiC rod growth that is the first step in developing a new rapid prototyping technique with laser chemical vapor deposition. In the study, SiC rods were generated with varying precursor pressure for 5 minutes. Deposition rates with varying precursor pressure, shapes of rods, surface roughness and component organization were investigated, in particular. Finally, several simple objects like a branch or a propeller were successfully fabricated using laser chemical vapor deposition.

• Advances in nano research
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• v.14 no.2
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• pp.195-200
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• 2023

Safety in sports is important because if an athlete has an accident, he may not be able to lead an everyday life for the rest of his life. The safety of sports facilities is very effective in creating people's sports activities, with the benefits of staying away from physical injury, enjoying sports, and mental peace. Everyone has the right to participate in sports and recreation and to ensure that they want a safe environment. This study prepares a very good Nickel-Cobalt -Silicon carbide (Ni/Co-SiC) nanocomposite with convenient geometry on the leg press machine rod, employing the pulse electrodeposition technique to reduce the rod's wear and increase the durability of sports equipment and control sports damages. The results showed that the Ni/Co-SiC nanocomposite formed at 2 A/dm2 shows extraordinary microhardness. The wear speed for the Ni/Co-SiC nanocomposite created at 4 A/dm2 was 15 mg/min, showing superior wear resistance. Therefore, the Ni/Co-SiC nanocomposite can reduce sports equipment's wear and decrease sports injuries. Ni-Co/SiC nanocomposite layers with various scopes of silicon carbide nanoparticles via electrodeposition in a Ni-Co plating bath, including SiC nanoparticles to be co-deposited. The form and dimensions of Silicon carbide nanoparticles are watched and selected using Scanning Electron Microscopy (SEM).