• Journal of Powder Materials
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• v.20 no.5
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• pp.366-370
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• 2013

The effects of $B_4C$ on the mechanical properties of WC/Ni-Si hardmetal were analyzed using sintered bodies comprising WC(70-x wt.%), Ni (28.5 wt.%), Si (1.5 wt.%), and $B_4C$ (x wt.%), where $$0{\leq_-}x{\leq_-}1.2$$ wt.%. Samples were prepared by a combination of mechanical milling and liquid-phase sintering. Phase and microstructure characterizations were conducted using X-ray diffractometry, scanning electron microscopy, and electron probe X-ray micro analysis. The mechanical properties of the sintered bodies were evaluated by measuring their hardness and transverse rupture strength. The addition of $B_4C$ improved the sinterability of the hardmetals. With increasing $B_4C$ content, their hardness increased, but their transverse rupture strength decreased. The changes of sinterability and mechanical properties were attributed to the alloying reaction between $B_4C$ and the binder metal (Ni, Si).

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.114-119
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• 2017

In this paper we present the search on HC-06 Bluetooth based driver module for emergency LED Multi-Directional Indicator. Nowadays, a growing trends in which electronic displays such as LED, LCD or plasma monitors are being installed in public places like bars, stores, entertainment areas, restaurants, lobbies, etc. In this paper, the study is curried out on efficiency of HC-06 Bluetooth module based controller driver that relates generally to the field of emergency signage management systems for displaying various indicator contents remotely on electronic displays in public and privates venues. It allows user smart devices interaction remotely with digital signage by providing content for displaying on at least one display in a venue. Depending on the emergency case, HC-06 Bluetooth based driver module proves the high efficiency as well as good performance of processing and communicating remotely the indicator based message that is displayed from a venue management control system by using smart devices. The system combines smart device that linked to HC-06 Bluetooth module with ATmega168/328 embedded micro controller which result by switching the displayer containing the digital signage indicator based message.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1080-1083
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• 2001

Ultrafine NiO/YSZ composite powders were prepared by using a glycine nitrate process for anode material of solid oxide fuel cells. The specific surface areas of synthesized NiO/YSZ composite powders were examined with controlling pH of a precursor solution and the content of glycine. The characteristics of synthesized composite powders were examined with X-ray diffractometer, a BET method with N$_2$absorption, scanning and transmission electron microscopy. The strongly acid precursor solution increased the specific surface area of the synthesized composite powders. This is suggested to be caused by the increased binding of metal ions and glycine under a strong acid solution of pH=0.5 that lets glycine consist of mainly the amine group of NH$_3$$\^$+/. After sintering and reducing treatment of NiO/YSZ composite powders synthesized by GNP, the Ni/YSZ pellet showed ideal micro-structure very fine Ni parties of 3-5${\mu}$m were distributed uniformly and fine pores around Ni metal particles were formed, thes, leading to an increase of the triple phase boundary among gas Ni and YSZ.

• Korean Journal of Materials Research
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• v.12 no.8
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• pp.661-668
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• 2002

A study was made to examine the electrical, compositional, structural and morphological properties of Ag thin films deposited by DC magnetron sputtering in $O_2$ atmosphere with deposition temperature from room temperature to 15$0^{\circ}C$ using in-line sputter system. The Ag films deposited at temperature above $100^{\circ}C$ in oxygen atmosphere gave a similar specific resistivity to and even lower oxygen content than those deposited using pure Ar sputter gas The Ag films deposited with pure Ar gas was mainly composed of crystallites with [111] preferred orientation, while, for those deposited in oxygen atmosphere, more than 50% of the volume was composed of crystallites with [100] orientation. The difference in the micro structure did not cause any difference in the specific resistivity of Ag films. The results showed that the transparent conducting oxide films and the Ag films could be processed sequentially in the same deposition chamber with careful control of deposition temperature, which might result in a cost reduction for constructing the large scale in-line deposition system.

• Macromolecular Research
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• v.15 no.6
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• pp.553-559
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• 2007

Nanocomposite films were prepared by sol-gel synthesis from vanadium triisopropoxide with $poly((oxyethylene)_9$ methacrylate)-graft-poly(dimethyl siloxane), POEM-g-PDMS, producing in situ growth of vanadium oxide within the continuous ion-conducting POEM domains of micro phase-separated graft copolymer. The formation of vanadium oxide was confirmed by wide angle x-ray scattering (WAXS) and Fourier transform infrared (FT-IR) spectroscopy. Small angle x-ray scattering (SAXS) revealed the spatially-selective incorporation of vanadium oxide in the POEM domains. Upon the incorporation of vanadium oxide, the domain periodicity of the graft copolymer monotonously increased from 17.2 to 21.0 nm at a vanadium content 14 v%, above which it remained almost invariant. The selective interaction of vanadium oxide with POEM was further verified by differential scanning calorimetry (DSC) and FT-IR spectroscopy. The nanocomposite films exhibited excellent mechanical properties $(l0^{-5}-10^{-7}dyne/cm^2)$, mostly due to the confinement of vanadium oxide in the POEM chains as well as the interfaces created by the microphase separation of the graft copolymer.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.104-111
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• 1998

The utilization of food garbage as composting was investigated by using the batch reactor and by varying the initial temperature of the fermentation reactors. As the straw controlled under 50 to 55% of moisture content and mixed 5% of EM(Effective Micro-organisms) microbial agent. An agitator continuously operated 1 rpm, supplying the amount of air(2l/kg.min). Reactor temperature changed three type of 40$\circ$C, 50$\circ$C, 60$\circ$C. In the case of 50$\circ$C operated 72 hr after organic contents showed lowest 48%, and weight reduction rate of showed 77%. The reaction gas was showed 30 min after 19. 9% of the lowest level at 20.9% concentration of oxygen and CO$_2$ gas was produced 0.9% due to organic disintegration on initial react time. NH$_4$, H$_2$ and CH$_4$ gas concentration showed 589 ppm lhr after, 83 ppm and 0.3%, but 8hr after gas product was complete. As using the straw of bulking agent, the Reduction by disintegration should be more effectively than composting.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.779-781
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• 2011

Drinking is one of most prominent causes for social problems like domestic violence, drinking and driving, and health problems. If who drunken can check promptly how much blood alcohol content, abstain from drunken driving or successive drinking schedule. In this paper, implementation of digital portable breathalyzer using semiconductor gas sensor based on MEMS were suggested. A small size micro controller with low power and surface mountable, ATMEGA48 can control semiconductor gas sensor digitally and display the value of alcohol concentration on LED.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.771-774
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• 2003

The mechanical properties of barrier ribs in PDP require quantification in order to control the defects and to increase the yield in the process. Several different types of rib materials were tested for hardness (H) and Young's modulus (E) with a microtip indenter (Berkovich type). For the assessment of fracture toughness of the rib, a macro Vikers indenter was used. The materials with 30wt% of filler were fired at between $490^{\circ}C$ and $570^{\circ}C$. As a result, the composite became fully densified at $520^{\circ}C$, which is near the T s (Littleton softening point) of glass frit. As the filler content increased, the fracture toughness also $(K_{IC})$ increased in the range of 0.60 to 2.63 $MPa{\cdot}m^{0.5}$ after sintering at $550^{\circ}C$. The results suggest that the application of a nano-indenter would be useful for testing the mechanical properties of barrier ribs.

• Carbon letters
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• v.10 no.3
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• pp.208-212
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• 2009

Alginate-chitosan blend containing coconut-based activated carbon was prepared as a drug delivery carrier in order to improve the loading and releasing capacity of the drug. The activated carbon was incorporated as effective adsorbent for drug due to the extremely high surface area and pore volume, high adsorption capacity, micro porous structure and specific surface activity. Alginate-chitosan blend containing coconut-based activated carbon showed the sustained release for a longer period. Alginate-chitosan blend showed higher release of drug as the pH increased and higher release of drug as the content of chitosan decreased due to the pH-dependent solubility of blend components.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.141-144
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• 2005

Sensing and interfacial evaluation of Ni nanowire strands/polymer composites were investigated using Electro-micromechanical technique. Electro-micromechanical techniques can be used as sensing method for micro damage, loading, temperature of interfacial properties. Using Ni nanowire strands/silicone composites with different content, load sensing response of electrical contact resistivity was investigated under tensile and compression condition. The mechanical properties of Ni nanowire strands with different type/epoxy composites were measured using uniformed cyclic loading and tensile test. Ni nanowire strands/epoxy composites showed humidity and temperature sensing within limited ranges, 20 vol% reinforcement. Some new information on temperature and humidity sensing plus loading sensing of Ni nanowire strands/polymer composites could be obtained from the electrical resistance measurement as a new concept of the nondestructive interfacial evaluation.