• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1119-1120
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• 2004

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.751-757
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• 2006

Recently, a new type of solid oxide fuel cells has been developed employing extremely thin oxide electrolyte. These fuel cells are expected to operate at significantly reduced temperature compared to conventional solid oxide fuel cells. Accordingly, they may resolve the stability and material selection issues of high temperature fuel cells. Furthermore, they may eliminate the limitations of polymer membrane fuel cells whose operation temperature is under $100^{\circ}C$. In this paper, we review the electrolytes for intermediate temperature operation. Then, we discuss the current development of thin film solid oxide fuel cells that possibly operated at low temperatures.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.87-92
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• 2010

Micromachining technology using a ultra-precision micromachining system is widely applied in the fields of optics, biotechnology and analytical chemistry, etc. specially in microfabrication of fresnel lens, light guide panels of TFT-LED and PDP ribs with micro-patterns, machining errors have an effect on the performance of those products. The deflection of tool and tool holder is known to be one of the very important factors that is due to machining errors in micromachining. The deflections of diamond tool and tool holder used in micro-grooving are analysed by FEM. We analysed by FEM. With an linearity valuation of FEM, deflection of tool and tool holder is calculated by using the data of cutting force which is acquired from micro-V groove machining experiments in micromachining system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.274-279
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• 2002

In this paper, the development process of an unique and creative micro/nano-structure fabrication technique based on micro/nano-tribology are reviewed and discussed. The so-called Mechano-Chemical Process(MCP), which has been developed since 1995 by Tribology Research Laboratory at Yonsei University with the motivation to overcome the demerits of the conventional photolithographic techniques, is based on the fundamental understanding of the interaction between the tool tip and the workpiece surface. This process is a maskless process which offers tremendous flexibility in surface patterns that can be created on a workpiece surface without using any capital intensive equipment. It Is capable of fabricating the prototypes of micro/nano-components, micro- structured surface with various geometries, micro-molds for making polymer or metal parts, and micro-fluidic channels for lab-on-a- chip

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.636-641
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• 2009

Recently, expansion of micro-technology parts requires micro-precision machining technology. Micro-groove machining is important to fabricate micro-grating lens and many micro-parts such as microscope lens, fluidic graphite channel etc. Conventional groove fabrication methods such as etching and lithography have some problems in efficiency and surface integrity. But, mechanical micromachining methods using single crystal diamond tools can reduce these problems in chemical process. For this reason, microfabrication methods are expected to be very efficient, and widely studied. This study deals with machinability in micro-precision V-grooves machining of nickel plated layer using non-rotational single crystal diamond tool and 3-axis micro stages. Micro V-groove shape, chip formation and tool wear were investigated for the analysis of machinability of Ni plated layer.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.33-36
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• 2009

Laser ablation with femtosecond lasers is highly promising for microfabrication of materials. Also, the high peak power of femtosecond lasers could induce a multiphoton absorption to ablate transparent materials. Similar results have also been were obtained in the case of optical fibers. In this paper, we present our experimental results of femtosecond laser microstructuring of optical fiber and its applications to microelectronic components and fiber optic devices. Finally, we directly produced micro holes with femtosecond laser pulses in a single step by moving an optical fiber in a preprogrammed structure. When water was introduced into a hole drilled from the bottom surface of the optical fiber, the effects of blocking and redeposition of ablated material were greatly reduced and the aspect ratio of the depth of the hole was increased. We have presented circular and rectangular-shaped holes in optical fiber.

• Smart Structures and Systems
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• v.21 no.3
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• pp.335-347
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• 2018

The fast-growing number of mobile and wearable applications has driven several innovations in small-scale electret-based energy harvesting due to the compatibility with standard microfabrication processes and the ability to generate electrical energy from ambient vibrations. However, the current modeling methods used to design these small scale transducers or microgenerators are applicable only for constant-speed rotations and small sinusoidal translations, while in practice, large amplitude sinusoidal vibrations can happen. Therefore, in this paper, we formulate an analytical model for electret-based microgenerators under general sinusoidal excitations. The proposed model is validated using finite element modeling combined with numerical simulation approaches presented in the literature. The new model demonstrates a good agreement in estimating both the output voltage and power of the microgenerator. This new model provides useful insights into the microgenerator operating mechanism and design trade-offs, and therefore, can be utilized in the design and performance optimization of these small structures.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1324-1326
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• 2006

In this study, an integrated microelectrode array was fabricated on glass slide using microfabrication technology. Probe DNAs consisting of mercaptohexyl moiety at their 5-end were spotted on the gold electrode using micropipette or DNA arrayer utilizing the affinity between gold and sulfur. Cyclic voltammetry in 5mM ferricyanide/ferrocyanide solution at 100 mV/s confirmed the immobilization of probe DNA on the gold electrodes. When several DNAs were detected electrochemically, there was a difference between target DNA and control DNA in the anodic peak current values. It was derived from specific binding of Hoechst 33258 to the double stranded DNA due to hybridization of target DNA. It suggested that this DNA chip could recognize the sequence specific genes. It suggested that multichannel electrochemical DNA microarray is useful to develop a portable device for clinical gene diagnostic system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.386-387
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• 2006

This research describes a new constructing method of multifunctional biosensor using many kinds of biomaterials. A metal particle and an array was fabricated by photolithographic. Biomaterials were immobilized on the metal particle. The array and the particles were mixed in a buffer solution, and were arranged by magnetic force interaction and self-assembly. A quarter of total Ni dots were covered by the particles. The binding direction of the particles was controllable, and condition of particles was almost with Au surface on top. The particles were successfully arranged on the array. The biomaterial activities were detected by chemiluminescence and electrochemical methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.404-405
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• 2006

Microarray-based DNA chips provide an architecture for multi-analyte sensing. In this paper, we report a new approach for DNA chip microarray fabrication. Multifunctional DNA chip microarray was made by immobilizing many kinds of biomaterials on transducers (particles). DNA chip microarray was prepared by randomly distributing a mixture of the particles on a chip pattern containing thousands of m-scale sites. The particles occupied a different sites from site to site. The particles were arranged on the chip pattern by the random fluidic self-assembly (RFSA) method, using a hydrophobic interaction for assembly.