• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.302-306
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• 2009

9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind of influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference has caused this with the ingredient a nanoparticle has. Ag is included 2 % and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.137-141
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• 2008

9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind a influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference was mused this with the ingredient a nanoparticle has. Ag is included 2% and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.366-366
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• 2016

Nanoscale observation of attachment systems of animals has revealed various exquisite multiscale architectures for essential functions such as gecko's locomotion, beetles' wing fixation, octopuses' sucking and crawling. In particular, the hierarchical 3-dimensional hexanonal nano-architectures in the tree frog's adhesion is known to have the capability of the enhancement of adhesion forces on the wet or rough surfaces due to the conformal contacts against rough surfaces and water-drainable micro channels. Here, we report that tree frog-inspired patches using unique artificial 3-dimensional hexagonal structures can be exploited to form reversibly enhanced adhesion against various highly curved and rough surfaces in dry and wet condition. To investigate the adhesion effect of micro-channels, we changed the arrangement of microstructure and spacing gaps between micro-channels. In addition, we introduced the 3-dimensional hexagonal hierarchical architectures to artificial patches to enhance to conformal contacts on the various rough surfaces such as skin and organs. Using the robust adhesion properties, we demonstrated the self-drainable and comfortable skin-attachable devices which can measure EKG (electrokardiogramme) for in-vitro diagnostics. As a result, bio-inspired programmable nano-architectures can be applied in versatile devices such as, medical patches, skin-attachable electronics etc., which would shed light on future smart, directional and reversible adhesion systems.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.162-168
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• 2006

To fabricate nanometer scale InGaAs HEMTs, we have successfully developed various novel nano-patterning techniques, including sidewall-gate process and e-beam resist flowing method. The sidewall-gate process was developed to lessen the final line length, by means of the sequential procedure of dielectric re-deposition and etch-back. The e-beam resist flowing was effective to obtain fine line length, simply by applying thermal excitation to the semiconductor so that the achievable final line could be reduced by the dimension of the laterally migrated e-beam resist profile. Applying these methods to the device fabrication, we were able to succeed in making 30nm $In_{0.7}Ga_{0.3}As$ HEMTs with excellent $f_T$ of 426GHz. Based on nanometer scale InGaAs HEMT technology, several high performance millimeter-wave integrated circuits have been successfully fabricated, including 77GHz MMIC chipsets for automotive radar application.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.386.1-386.1
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• 2014

The ionic polymer-metal composite (IPMC), a type of electro-active polymer material, has received enormous interest in various fields such as robotics, medical sensors, artificial muscles because it has many advantages of flexibility, light weight, high displacement, and low voltage activation, compare to traditional mechanical actuators. Mostly noble metal materials such as gold or platinum were used to form the electrode of an IPMC by using electroless plating process. Furthermore, carbon-based materials, which are carbon nanotube (CNT) and reduced graphene-CNT composite, were used to alter the electrode of IPMC. To form the electrode of IPMC, we employ the synthesized graphene on copper foil by chemical vapor deposition method and use the transfer process by using a support of PET/silicone film. The properties of graphene were evaluated by Raman spectroscopy, UV/Vis spectroscopy, and 4-point probe. The structure and surface of IPMC were analyzed via field emission scanning electron microscope. The fabricated IPMC performance such as displacement and operating frequency was measured in underwater.

• Korean Journal of Materials Research
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• v.30 no.2
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• pp.93-98
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• 2020

Effective control of the heat generated from electronics and semiconductor devices requires a high thermal conductivity and a low thermal expansion coefficient appropriate for devices or modules. A method of reducing the thermal expansion coefficient of Cu has been suggested wherein a ceramic filler having a low thermal expansion coefficient is applied to Cu, which has high thermal conductivity. In this study, using pressureless sintering rather than costly pressure sintering, a polymer solution synthesis method was used to make nano-sized Cu powder for application to Cu matrix with an AlN filler. Due to the low sinterability, the sintered Cu prepared from commercial Cu powder included large pores inside the sintered bodies. A sintered Cu body with Zn, as a liquid phase sintering agent, was prepared by the polymer solution synthesis method for exclusion of pores, which affect thermal conductivity and thermal expansion. The pressureless sintered Cu bodies including Zn showed higher thermal conductivity (180 W/m·K) and lower thermal expansion coefficient (15.8×10^-6/℃) than did the monolithic synthesized Cu sintered body.

• Journal of the Semiconductor & Display Technology
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• v.5 no.4 s.17
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• pp.1-4
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• 2006

Recently, with rapid development of digital media like semiconductor and large flat panel display, the manufacturing equipment is required to have high precision over large travel range. Moreover it should have high product throughput. To achieve high product throughput, a controller should perform fast point-to-point motion and high precision positioning after settling in spite of external disturbances or residual vibrations. We proposed a new mode switching control algorithm with an application to dual stage for long range and high precision positioning. The proposed algorithm uses a proximate time-optimal servomechanism for the fast settling and a time-delay controller for the high precision positioning. Experimental results show that the proposed method enables smooth mode switching and improves the settling time and the precision accuracy after settling by over than 33% and 45%, respectively.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.252-257
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• 2004

Nanometer-sized structures are being applied to many devices including micro/nano electronics, optoelectronics, quantum devices, MEMS/NEMS, biosensors, etc. Especially, the thin film with submicron thickness is a basic structure for fabricating these devices, but its mechanical behaviors are not well understood. The mechanical properties of the thin film are different from those of the bulk structure and are difficult to measure because of its handling inconvenience. Several techniques have been applied to mechanical characterization of the thin film, such as nanoindentation test, micro/nano tensile test, strip bending test, etc. In this study, we focus on the strip bending test because of its high accuracy and moderate specimen preparation efforts, and measure Au thin film, which is a very popular material in micro/nano electronic devices. Au film is deposited on Si substrate by evaporation process, of which thickness is 100nm. Using the strip bending test, we obtain elastic modulus, yield and ultimate tensile strength, and residual stress of Au thin film.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.2
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• pp.27-32
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• 2008

A current research basically diverted towards an increase in the operational output with the minimization of the materials used, which ultimately scaled down the dimensions of ceramic electronic components. In this direction the nano-technology pave the revolutionary changes in particular the electronic industries. The applications of nano-sized particles or nano-sized materials are hence, playing a significant role for various purposes. The PZT(lead, zirconium, titanium) based ceramics which, are reported to be ferroelectric materials have their important applications in the areas of surface acoustic waves (SAW), filters, infrared detectors, actuators, ferroelectric random access memory, speakers, electronic switches etc. Moreover, these PZT materials possess the large electro mechanical coupling factor, large spontaneous polarization, low dielectric loss and low internal stress etc. Hence, keeping in view the unique properties of PZT piezoelectric ceramics we also tried to synthesize indigenously the small sized PZT ceramic powder in the laboratory by using the modified sol-gel approach. In this paper, propyl alcohol based sol-gel method was used for preparation of PZT piezoelectric ceramic. The powder obtained by this sol-gel process was calcined and sintering to reach a pyrochlore-free crystal phase. The characterization of synthesized material was carried out by the XRD analysis and the surface morphology was determined by high resolution scanning electron microscopy.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.641-644
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• 2021

Wearable devices and IoT are being utilized in various fields, where all systems are developing in the direction of multi-functionality, low power consumption, and high speed. In this paper, we propose a DC -DC Step-down C onverter for IoT smart devices. The proposed DC -DC Step-down converter is composed of a control block of the power supply stage. It also consists of an overheat protection circuit, under-voltage protection circuit, an overvoltage protection circuit, a soft start circuit, a reference voltage circuit, a lamp generator, an error amplifier, and a hysteresis comparator. The proposed DC-DC converter was designed and fabricated using a Magnachip / Hynix 180nm CMOS process, 1-poly 6-metal, the measured results showed a good match with the simulation results.