• Title, Summary, Keyword: Expanded metal

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Surface Analysis and Electrical Properties for Complex with Concentration of Metal ion in LB Ultra-thin Films Using IMI-O Polymer (IMI-O 고분자 LB막의 금속 이온의 착체 농도에 따른 전기특성 및 표면분석)

  • Jung, S.B.;Yoo, S.Y.;Park, J.C.;Kwon, Y.S.
    • Proceedings of the KIEE Conference
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    • pp.1711-1713
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    • 2000
  • We fabricated an IMI-O polymer containing an imidazole group that could form a complex structure between the monolayer and the metal ions at the air-water interface. Also, the surface analysis and the electrical properties of metal ion complex of Langmuir-Blodgett (LB) films were investigated by using $\pi$-A isotherms. Atomoic force microscopy (AFM), current-voltage (I-V) measurements. In the $\pi$-A isotherms the molecular area was expanded with $Fe^{3+}$ concentration increase. It is considered that the expansion of molecular area is due to electrostatic repulsion between the polymer chains and hydrophobic increase of ionic strength. In the I-V characteristics, it is found that the limiting area has effects on the change of conductivity. And, the dielectric relaxation time decreased for increase of the $Fe^{3+}$ concentration.

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Effect of Polymer Content on Synthesis Process and Microstructure of Alumina-Zirconia Composite (알루미나-지르코니아 복합체의 제조공정 및 미세구조에 미치는 폴리머 첨가의 영향)

  • 이상진;권명도;이충효;조경식
    • Journal of Korean Powder Metallurgy Institute
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    • v.10 no.5
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    • pp.310-317
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    • 2003
  • Two-component ceramic (alumina-zirconia) composites were fabricated by a soft-solution process in which polyethylene glycol (PEG) was used as a polymeric carrier. Metal salts and PEG were dissolved in ethyl alcohol without any precipitation in 1:1 volume ratio of alumina and zirconia. In the non-aqueous system, the flammable solvent made explosive, exothermic reaction during drying process. The reaction resulted in formation of volume expanded, porous precursor powders by a vigorous decomposition of organic components in the precursor sol. The PEG content affected the grain size of sintered composites as well as the morphology of precursor powders. The difference of microstructure in sintered composite was attribute to the solubility and homogeneity of metal cations in precursor sol. At the optimum amount of the PEG polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. It made less agglomerated particles in the precursor sol and affected on uniform grain size in sintered composite.

Three-dimensional MXene (Ti3C2Tx) Film for Radionuclide Removal From Aqueous Solution

  • Jang, Jiseon;Lee, Dae Sung
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • pp.379-379
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    • 2018
  • MXenes are a new family of 2D transition metal carbide nanosheets analogous to graphene (Lv et al., 2017; Sun et al., 2018). Due to the easy availability, hydrophilic behavior, and tunable chemistry of MXenes, their use in applications for environmental pollution remediation such as heavy metal adsorption has recently been explored (Li et al., 2017). In this study, three-dimensional (3D) MXene ($Ti_3C_2T_x$) films with high adsorption capacity, good mechanical strength, and high selectivity for specific radionuclide from aquose solution were successfully fabricated by a polymeric precursor method using vacuum-assisted filtration. The highest removal efficiency on the films was 99.54%, 95.61%, and 82.79% for $Sr^{2+}$, $Co^{2+}$, and $Cs^+$, respectively, using a film dosage of 0.06 g/ L in the initial radionuclide solution (each radionuclide concentration = 1 mg/L and pH = 7.0). Especially, the adsorption process reached an equilibrium within 30 min. The expanded interlayer spacing of $Ti_3C_2T_x$ sheets in MXene films showed excellent radionuclide selectivity ($Cs^+$ and/or $Sr^{2+}/Co^{2+}$) (Simon, 2017). Besides, the MXene films was not only able to be easily retrieved from an aqueous solution by filtration after decontamination processes, but also to selectively separate desired target radionuclides in the solutions. Therefore, the newly developed MXene ($Ti_3C_2T_x$) films has a great potential for radionuclide removal from aqueous solution.

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Effect of Sound-Absorbing Materials on the Characteristics of Supersonic Jet Noise (흡음재가 초음속 제트의 소음특성에 미치는 영향)

  • Gwak, Jong-Ho;Kweon, Yong-Hun;Aoki, Toshiyuki;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • pp.1499-1504
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    • 2004
  • The effects of absorbing materials on the characteristics of supersonic jet noise were experimentally investigated using a convergent-divergent nozzle with a design Mach number of 2.0. Overall sound pressure levels (OASPL) and noise spectra were obtained at far-field locations. Schlieren optical system was used to visualize the flow-fields of supersonic jets. In order to investigate the effect of absorbing materials, baffle plates of different materials (metal, grass wool and polyurethane foam) were installed at the exit of the nozzle. Experiment was carried out over a wide range of nozzle pressure ratios from 2.0 and 18.0, which corresponds to over- and under-expanded conditions. The results obtained show that the screech tone amplitude and the overall sound pressure level reduce by using the baffle plates of absorbing materials, compared with the metal baffle plate. It is also found that the characteristics of supersonic jet noise are strongly dependent on the size of baffle plate.

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A Kinetic Study of Non-uniform Thermal Conductive Reaction Block (비균일 열전도성 반응블럭의 반응특성 연구)

  • Park, Seong Ho;Yoon, Yea Il;Kim, Sung Hyun
    • Applied Chemistry for Engineering
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    • v.8 no.5
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    • pp.872-879
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    • 1997
  • The nonuniform thermal conductive reaction blocks were manufactured by impregnation of metal salts on the expanded graphite to improve the heat and mass transfer ability of reaction block for the chemical heat pump using the reaction of ammonia and metal salts(halide). The nonuniform blocks were designated to increase apparent density, like 165, 222, 279, 337, $394kg/m^3$ radially The experimental results showed that the heat transfer characteristics of nonuniform blocks were better than uniform blocks. As the reaction of ammonia repeated, the volumetric expansion in the reaction block makes the mass transfer improve, and the reproducibility better.

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Fabrication and characteristics of MOSFET protein sensor using gold-black gate (Gold-Black 게이트를 이용한 MOSFET형 단백질 센서의 제조 및 특성)

  • Kim, Min-Suk;Park, Keun-Yong;Kim, Ki-Soo;Kim, Hong-Seok;Bae, Young-Seuk;Choi, Sie-Young
    • Journal of Sensor Science and Technology
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    • v.14 no.3
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    • pp.137-143
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    • 2005
  • Research in the field of biosensor has enormously increased over the recent years. The metal-oxide semiconductor field effect transistor (MOSFET) type protein sensor offers a lot of potential advantages such as small size and weight, the possibility of automatic packaging at wafer level, on-chip integration of biosensor arrays, and the label-free molecular detection. We fabricated MOSFET protein sensor and proposed the gold-black electrode as the gate metal to improve the response. The experimental results showed that the output voltage of MOSFET protein sensor was varied by concentration of albumin proteins and the gold-black gate increased the response up to maximum 13 % because it has the larger surface area than that of planar-gold gate. It means that the expanded gate allows a larger number of ligands on same area, and makes the more albumin proteins adsorbed on gate receptor.

Structural performance of ferrocement beams reinforced with composite materials

  • Shaheen, Yousry B.I.;Eltaly, Boshra A.;Abdul-Fataha, Samer G.
    • Structural Engineering and Mechanics
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    • v.50 no.6
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    • pp.817-834
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    • 2014
  • An experimental program was designed in the current work to examine the structural behavior of ferrocement beams reinforced with composite materials under three point loadings up to failure. The experimental program comprised casting and testing of twelve ferrocement beams having the dimensions of 120 mm width, 200 mm depth and 1600 mm length. The twelve beams were different in the type of reinforcements; steel bars, traditional wire meshes (welded and expanded wire meshes) and composite materials (fiberglass wire meshes and polypropylene wire meshes). The flexural performances of the all tested beams in terms of strength, ductility, cracking behavior and energy absorption were investigated. Also all the tested beams were simulated using ANSYS program. The results of the experimental tests concluded that the beam with fiber glass meshes gives the lowest first crack load and ultimate load. The ferrocement beam reinforced with four layers of welded wire meshes has better structural behavior than those beams reinforced with other types of wire meshes. Also the beams reinforced with metal wire meshes give smaller cracks width in comparing with those reinforced with non-metal wire meshes. Also the Finite Element (FE) simulations gave good results comparing with the experimental results.

Decomposition Mechanism of Waste Hard Metals using by ZDP (Zinc Decomposition Process) (ZDP(Zinc Decomposition Process)를 이용한 폐 초경합금의 분해기구)

  • Pee, Jae-Hwan;Kim, Yoo-Jin;Sung, Nam-Eui;Hwang, Kwang-Taek;Cho, Woo-Seok;Kim, Kyeong-Ja
    • Journal of the Korean Ceramic Society
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    • v.48 no.2
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    • pp.173-177
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    • 2011
  • Decomposition promoting factors and decomposition mechanism in the zinc decomposition process of waste hard metals which are composed mostly of tungsten carbide and cobalt were evaluated. Zinc volatility amount was suppressed and zinc valatilization pressure was produced in the reaction graphite crucible inside an electric furnace for ZDP. Reaction was done for 2 h at $650^{\circ}C$, which 100 % decomposed the waste hard metals that were over 30 mm thick. As for the separation-decomposition of waste hard metals, zinc melted alloy formed a liquid composed of a mixture of ${\gamma}-{\beta}1$ phase from the cobalt binder layer (reaction interface). The volume of reacted zone was expanded and the waste hard metal layer was decomposed-separated horizontally from the hard metal. Zinc used in the ZDP process was almost completely removed-collected by decantation and volatilization-collection process at $1000^{\circ}C$.

Thermal and Structural Analyses of Semi-metallic Gasket Joined with Graphite Seal for Ship Engine Piping Flange (선박엔진 배관 플랜지용 세미금속 가스켓의 열전달 및 구조해석)

  • Oh, Jeong-seok;Lee, In-sup;Yoon, Han-ki;Sung, Heung-kyoung
    • Journal of Ocean Engineering and Technology
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    • v.31 no.5
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    • pp.352-356
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    • 2017
  • We performed thermal and structural analyses to evaluate the structural integrity of a semi-metal gasket for a flange with increases in the internal fluid temperature and pressure using a commercial FEA program. As a thermal analysis result, the temperature distribution of the gasket body increased with an increase in the internal fluid temperature until the maximum fluid temperature of $600^{\circ}C$. In addition, the structural analysis showed that contact pressures of more than 35 MPa occurred uniformly in the graphite seal regions. It was found that no fluid leakage occurred under the load conditions for the structural analysis because the contact pressure in the graphite seal region was greater than the maximum internal fluid pressure of 35 MPa. Therefore, we demonstrated the structural integrity of the semi-metal gasket by performing the thermal and structure analyses under the maximum fluid temperature of $600^{\circ}C$ and the internal fluid pressure of 35 MPa.

Effects of Internal and External Characteristics of Korean SMEs on the Introduction of Smart Factory : An Exploratory Investigation on the Metal Processing Industry (국내 중소기업의 내·외부 요인이 스마트팩토리의 도입에 미치는 영향에 관한 탐색적 연구 : 금속가공업을 중심으로)

  • Lee, Jonggak;Kim, Jooheon
    • Journal of Information Technology Services
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    • v.19 no.6
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    • pp.97-117
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    • 2020
  • Five years have passed since the introduction of the smart factory amid the new opportunities for growth and job creation in relation to domestic manufacturing companies. Nevertheless, there is a lack of analysis on SMEs introduction smart factories. This study empirically analyzed the effects on the introduction of smart factories of domestic metal processing SMEs by distinguishing the characteristics of enterprises In this study, 103 companies which introduced smart factories and another 106 companies which did not introduce them were sampled. The Introduction of the Smart Factory was analyzed by four categories such as the Company characteristics (R&D capability, product production capability, organizational change), entrepreneur characteristics (risk sensitivity), relational characteristics (trust, dependence, cooperation, Influence), and structural characteristics (competition). As a result of the research, we found out product production capacity, risk sensitivity, trust and cooperation, Influence, and competition are statistically significant in the introduction of smart factory. But competition was characterized by a negative (-) sign opposite to the hypothesis. This study is meaningful in that the scope of the analysis has been expanded by analyzing whether smart factory was introduced or not considering the characteristics of the company. And there should be continuous research on its utilization as well as the introduction of smart factory.