• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.574-581
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• 2016

In this study, CNT functionalized with pyrrolidine ring via 1,3-dipolar cycloaddition reaction with various amino acid and aldehyde was synthesized. Metallocene was subsequently immobilized on the functionalized CNT and CNT/polyethylene composite was prepared via in-situ ethylene polymerization. The polymerization activities of metallocene supported on CNT functionalized with glycine and benzaldehyde (Gly+BA-CNT) were similar to those of metallocene supported on CNT functionalized with N-benzyloxycarbonylglycine and paraformaldehyde (Z-Gly+PFA-CNT) although its Zr content was lower than that of Z-Gly+PFA-CNT. In the case of metallocene supported on Z-Gly+PFA-CNT, the even distribution of active sites hindered the diffusion of ethylene monomer and cocatalyst MAO due to steric hindrance during ethylene polymerization. Compared to polyethylene produced from homogeneous metallocene catalysts, CNT/PE composites had a higher initial degradation temperature ($T_{onset}$) and maximum mass loss temperature ($T_{max}$). It suggests that pyrrolidine functionalized CNT is uniformly dispersed and strongly interacted with the PE matrix, enhancing the thermal stability of PE.

• Clean Technology
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• v.18 no.2
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• pp.170-176
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• 2012

A series of acrylic copolymers containing perfluoroalkyl acrylate were synthesized by 2-step emulsion polymerization of variety of acrylate monomers (ethyl acrylate, butyl acrylate or methyl methacrylate) with perfluoroalkyl ethyl acrylate (PFA) and glycidyl methacrylate (GMA) monomers. This study focused on effects of monomer compositions (the kind of acrylate monomer, contents of PFA and GMA) and composition of surfactants [(sodium dodecyl sulphate/nonylphenol 10mole ethoxylate (NP-10)] and initiator content on the contact angles and surface free energy. It was found that the copolymer having an optimum composition (BA : 87 wt%, GMA : 8.7 wt% and PFA : 4.3 wt%) was shown to be quite surface active [surface free energy : 19.89 mN/m and contact angles : $103.5^{\circ}$ (water) and $78.7^{\circ}$ (methylene iodide)] in the solid state. This result suggests that the optimal copolymer containing fluorinated monomer synthesized in this study have high potential as a low surface energy material, which may have high oil- and water-repellent surface and have been proposed as acrylic syntan for leather and also as soil-resistant/oil and water repellent coating for textiles and wood etc.

• The Journal of the Korean dental association
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• v.32 no.10 s.305
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• pp.751-753
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• 1994

• Journal of KSNVE
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• v.8 no.6
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• pp.1053-1061
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• 1998

In this paper. the power flow analysis(PFA) method is applied to the prediction of the vibrational energy density and intensity of coupled co-planar plates. To cover the energy transmission and reflection at the joint of the plates. the wave transmission approach is Introduced with the assumption that all the incident waves are normal to the joint. By changing the frequency ranges and internal loss factors. we have obtained the reliable PFA results. and compared them with the analytical exact solutions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.797-800
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• 2006

The power flow analysis(PFA) can be effectively used to predict structural vibration in medium-to-high frequency ranges. In this paper, vibration experiment has been performed to observe the analytical characteristics of the power flow analysis of the vibration of a plate. In the experiment, the loss factor of the plate and the input mobility at a source point have been measured. The data for the loss factor has been used as the input data to predict the vibration of the plate with PFA. The frequency response functions have been measured over the surface of the plate. The comparison between the experimental results and the predicted results for the frequency responsefunctionshasbeenperformed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.90-93
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• 2005

Power Flow Boundary Element Method(PFBEM) has been used as a promising tool for radiation problems in the midium-to-high frequency. PFBEM is the numerical method that applies boundary element technique to Power Flow Analysis (PFA). Indirect PFBEM is developed for acoustic scattering problems in the open field and in various frequency. To verify the analytic results of indirect PFBEM for acoustic scattering problems are compared with those of SYSNOISE, and the results using two analytic methods show a good agreement.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.245-250
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• 1992

In this paper, we present a nev algorithm for the fast computation of the discrete cosine transform(DCT). This algorithm consists of the three dimensional prime factor-decomposed algorithm(PFA) and three dimensional common factor-decomposed algorithm(CFA). We can compute N-point DCT for the number N decomposable Into three relative prime numbers using PFA and into three common numbers using CFA. We also show input and output index mapping for the three decomposition. it results in requiring fever multiplicaions than the previous algorithms. Particularly, for the large number N, it is more powerful in reducing the number of multiplication.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.183-190
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• 2005

In the process of ice-slurry making, ice adhesion on cooling wall or in narrow flow Path disturbs continuous ice formation. In this study, the effect on the ice adhesion to cooling surface by some freezing experiments was investigated, quantitatively. Three types of solutions were frozen in various coating vessels with stirring. In the experiment, the ice adhesion between cooling wall and Ice-slurry was evaluated by measuring stirring power. From the result, the stirring power of slurry mixture in PTFE-coating vessel was smaller than those in PE-coating, PFA-coating and bare SUS vessel. Especially, in EG H PG 1.S/ HD 1.5 mass$\%$ solution, the stirring power in the PE-coating vessel was smaller than that in the PFA-coating or SUS vessel.

• Journal of Ship and Ocean Technology
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• v.6 no.2
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• pp.1-11
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• 2002

For the analysis of vibrational energy density and intensity of partitioned complex system structures in medium-to-high frequency ranges, A software based on the Power Flow Analysis(PFA) has been developed for the plate elements. The flexural, longitudinal and shear waves in plates are formulated and the joint element equations for multi-coupled plates are fully developed. Also, the wave transmission approach has been introduced to cover the energy transmission and reflection at the joint plate elements. To confirm the validity of the developed PFA software, the submarine-shaped complex structures are used for the analysis of vibration intensity and energy density.

• Analytical Science and Technology
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• v.26 no.1
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• pp.51-60
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• 2013

The geometrical parameters, vibrational frequencies, and adiabatic electron affinities (AEAs) for c-$C_nF_{2n}$ (n=8, 9) and $C_{10}F_{18}$ (perfluorodecalin) have been investigated using various quantum mechanical techniques. The possible structures for the neutrals and anions of c-PFA are fully optimized and electron affinities are predicted using energy difference between the neutral and anion. The harmonic vibrational frequencies are also determined and zero-point vibrational energies (ZPVEs) are considered for the better prediction of the electron affinities. The electron affinities are predicted to be 1.18 eV for c-$C_8F_{16}$ (ortho), 1.37 eV for c-$C_9F_{18}$, and 1.38 eV for $C_{10}F_{18}$ (perfluorodecalin) at the MP2 level of theory after ZPVE correction.