• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.338-341
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• 2015

Epoxy/micro-sized alumina composite was prepared, and the effects of alumina content on the dielectric properties were investigated in order to develop an insulation material for gas-insulated switchgears (GIS). Nano-sized alumina (average particle size: 30 nm) was also incorporated into the epoxy/micro-sized alumina composite. Dielectric tests were carried out in ASTM D 150, and capacitance (Cp) and dielectric loss (tanδ) were measured. The dielectric constant increased with increasing alumina content in the epoxy/micro-alumina system and the epoxy/micro-alumina/nano-alumina system. As 1,3-diglycidyl glyceryl ether (DGE) content increased, the dielectric constant decreased and dielectric loss increased. This ocurred as a result of the weak electric field enhancement due to homogeneous dispersion of micro- and nano-sized alumina particles in an epoxy composite.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_1
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• pp.125-137
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• 2020

Tracking micro-sized insects is one of the challenges of protecting ecosystems and biodiversity. In this study, we propose an approach for the autonomous tracking of micro-sized flying insects, and develop an unmanned aerial vehicle (UAV)-based robotic system. The Kalman filter is applied to the received signal strength emitted from radio telemetry to estimate the position while reducing the measurement error and noise. The autonomous tracking strategy is a method in which the UAV rotates at one point to measure the signal strength and control its position in the strongest direction of the signal. We also design a system architecture comprising a tracking sensor system and a UAV system for micro-sized insects. The estimation and autonomous tracking of the target position by the proposed system are verified and evaluated through dynamic simulation. Therefore, in this study, we propose and validate a UAV-based tracking system for micro-sized flying insects, which has not been proposed in studies conducted thus far.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.6
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• pp.47-59
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• 2017

Korean Economy has been developed by the Korean Government's Support for the Large-sized Firms. This Government Policy causes the Polarization between Large-sized and Micro-sized Firms Aggravated. Micro-sized Firms are distributed over the Whole Industry Area, and can also cause the Economic Crisis If They are crashed down. Therefore Government Policy for the Micro-sized Manufacturing Industry is very Important Issue. This Paper Focused on the Analysis of Current Status for the Shoes Micro Manufacturing Industry. For the Effective Analysis, This Paper uses the Statistical Data Open to the Public and also conducts the Survey for the Micro-sized Firms in Busan. Statistical Program is used for Analyzing the Collected Data and the Major Findings are as Follows. First, Shoes Industry is led by the Micro and Small & Medium sized Firms rather than the Large-sized. And the Micro-sized Firms are getting the High Rate among the Whole Shoes Industry. Busan is heavily populated Area as the Origin of Shoes Industry. Second, even though Most of the Owner of the Micro-sized Firms have the High Technology Skill Level, Worker's Aging Phenomenon gets Worse and causes the Technology Handing down to the Next Generation Difficult. Third, Because the Factory Facility of the Micro-sized Firms is Dirt and Unstable, the Modernized Manufacturing Infrastructure such as the Apartment Factory Facility is Necessary. Forth, as the Micro-sized Firms which have the Intangible Asset such as Patent is Few, the Government Policy for Encouraging the Patent Application is strongly Needed. Fifth, Entrepreneurship and Collaboration Mind between Micro-sized Firms are Lacked, so Establishment of the Cooperative Union is required. Finally, the Effort for the Systemic Planning for the Management is lacked, and the Introduction of the Management Innovation is strongly needed. The Limitation and Future Research Direction is also discussed.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.05a
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• pp.3.1-3.1
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• 2007

• Transactions on Electrical and Electronic Materials
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• v.16 no.5
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• pp.260-263
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• 2015

Epoxy/micro-sized alumina composite was prepared and the effects of alumina content on the electrical and mechanical properties were investigated in order to develop an insulation material for gas insulated switchgear (GIS). Nano-sized alumina (average particle size: 30 μm) was also incorporated into the epoxy/micro-sized alumina composite. An electrical insulation breakdown strength test was carried out in sphere-sphere electrodes and the data were estimated by Weibull statistical analysis. Tensile strength was measured at a crosshead speed of 10 mm/min using a universal testing machine. Alumina content was varied from 0 wt% to 70 wt%.). As micro-sized alumina content increased, insulation breakdown strength increased until 40 wt% alumina content and decreased after that content. The tensile strength of a neat epoxy system was 82.2 MPa and that value for 60 wt% alumina content was 91.8 MPa, which was 111.7% higher than inthe neat epoxy system. The insulation breakdown strength of micro-sized alumina (60 wt%)/nano-sized alumina (1 phr) glycerol diglycidyl ether (GDE) (1 phr) composite was 54.2 MPa, which was 116% higher than the strength of the system without nano-sized alumina.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.20-25
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• 2014

Explosion characteristics of micro-sized aluminum dusts had been studied by many researchers, but the research of nano-sized aluminum dusts were very insufficient. In this study, an experimental investigation was carried out on the influences of nano and micro-sized aluminum dusts (70 nm, 100 nm, $6{\mu}m$, $15{\mu}m$) on dust explosion properties of aluminum particles by using 20 L explosion apparatus. With decreasing of particle size in suspended aluminum dusts, the LEC (lower explosion concentration) of nano-sized aluminum is lower than that of micro-sized aluminum. The particle size change of nano-sized aluminum dusts seems no obvious explosion differences than that of micro-sized aluminum dusts. From the observation of nano-sized aluminum particles by TEM (Transmission Electron Microscopy), it is estimated that increase of particles aggregation may have effects on the explosion characteristics of aluminum nanopowders.

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.86.2-86
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• 2002

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.5
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• pp.26-32
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• 2009

As a part of utilizing the nanocellulose (NC) from lignocellulosic components of wood biomass, this paper reports preliminary results on the products of sulfuric acid hydrolysis. The purpose of this study was to investigate the morphology of both NC and micro-sized cellulose fiber (MCF) isolated by acid hydrolysis from commercial microcrystalline cellulose (MCC). Field emission.scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to observe the acid hydrolysis suspension, NC, and MCF. The electron microscopy observations showed that the acid hydrolysis suspension, before separation into NC and MCF by centrifugation, was composed of nano-sized NCs and micro-sized MCFs. The morphology of isolated NCs was a whisker form of rod-like NCs. Measurements of individual NCs using TEM indicated dimensions of 6.96$\pm$0.87 nm wide by 178$\pm$55 nm long. Observations of the MCFs showed that most of the MCC particles had de-fibered into relatively long fibers with a diameter of 3-9 ${\mu}m$, depending on the degree of acid hydrolysis. These results suggest that proper technologies are required to effectively realize the potentials of both NCs and MCFs.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.158-163
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• 2001

Operators suffer much difficulty in manipulating micro/nano-sized objects without the assistance of human interfaces, due to the scaling effects in micro/nano world. This paper presents a micro manipulation system based on the teleoperation techniques which enables the operators to manipulate the objects with ease by transferring both human motion and manipulation skill to a micromanipulator. An experimental setup consisting of a micromanipulator operated under stereo-microscope with the help of intelligent user interface provides a tool that can be used to visualize and manipulate micro-sized 3D objects in a controlled manner. The key features of a micro manipulation system and control strategies using teleoperation techniques for handling micro objects are presented. Experimental results demonstrate the feasibility of this system in precisely controlling trapping and manipulation of micro objects based on teleoperation techniques.

• Carbon letters
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• v.16 no.3
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• pp.215-218
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• 2015

Carbon micro particles with dimple patterns were produced by electro-spraying a solution of pitch in tetrahydrofuran. Particle formation depended on separation in an electrical field and volatilization of the solvent. More than 80% of the obtained carbon exhibited an average particle size of less than 50 μm. X-ray diffraction analysis suggests that the carbon with dimple patterns has increased crystallinity after heat treatment.