• Title/Summary/Keyword: co-ideal

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Gas-Transport Properties through Various Cations Exchanged Sulfonated Poly(ether imide) Membranes

  • Rhim, Ji-Won
    • Korean Membrane Journal
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    • v.3 no.1
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    • pp.51-58
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    • 2001
  • The surface of Poly(ether imide) (PEI) membranes has been sulfonated using CIS03H. The resulting membranes were characterized through the analysis of ESCA and contact angle measurements The sulfonated PEI membranes were exposed to gases of $O_2$, $N_2$, and $CO_2$ to measure the permeation rates and ideal separation factors. In addition, the diffusivities and solubilities of individual gases were measured. The diffusivity effect is more dominant than the solubility one on gas transports.

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Analysis of Ferromagnetic and Spin Wave Resonance Signals in CoFeB Thin Films (CoFeB 박막 재료에서 강자성 및 스핀파 공명 신호 분석)

  • Kim, Dong Young;Yoon, Seok Soo
    • Journal of the Korean Magnetics Society
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    • v.24 no.6
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    • pp.165-170
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    • 2014
  • We analyzed the ferromagnetic and spin wave resonance signals measured in amorphous CoFeB thin films with different thickness. The ferromagnetic resonance field ($H_{FMR}$) was not depend on the thickness of CoFeB films, but the spin wave resonance field ($H_{SWR}$) was well fitted with the theoretical prediction depending on the thickness. The uniaxial anisotropy field of $H_k$ = 37 Oe was obtained from the angular dependent $H_{FMR}$ in CoFeB films. The $H_{SWR}$ showed same angular behaviors with $H_{FMR}$, however, the amplitude of spin wave resonance signals showed 5.7 times higher than that of ferromagnetic resonance signals in CoFeB film with t = 100 nm. The higher signals were due to the two reasons; one was the small damping for the spin wave propagation without degradation, the other was uniform magnetization for the ideal standing wave modes.

Separation of Gas Based on PTMSP-silica-PEI Composites (PTMSP-silica-PEI 복합막에 의한 기체 분리에 관한 연구)

  • Kang Tae-Bum;Hong Se-Lyung
    • Membrane Journal
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    • v.16 no.2
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    • pp.123-132
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    • 2006
  • The PTMSP-silica-PEI composite membranes were synthesized from tetraethoxysilane (TEOS) and poly (1-trimethylsilyl-1-propyne) (PTMSP) by sol-gel process. The PTMSP-silica nanocomposite membranes were characterized by $^1H-NMR$, FT-IR, TGA, XPS, SEM, GPC and gas permeation measurements were accomplished with $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4$. The gases permeability increased with increasing TEOS content. Both the permeability and selectivity of $H_2,\;CH_4$ increased to 15 wt% TEOS. While the permeability of $O_2,\;CO_2$ increased without decrease of selectivity.

A Study on Accuracy Detection Method for Signal Peak Voltage (신호용 PEAK 전압 정밀검출에 관한 연구)

  • Park, Ho-Chul;Sung, Hyung-Su;Han, Seung-Moon;Han, Jeong-Hoon
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2528-2530
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    • 2000
  • In general, Diode makes a major role in electronic circuit. For example, switching of rectifier, cross current of switching rectifier, energy transfer of electronic element and reverse charge of capacitor, voltage insulation, energy feedback from load to power supply, and such as recovery of storaged energy. Generally, We regard power diode as ideal element, but it has a certain boundary actually, specially, We use diode for detecting circuit peak hold voltage signal. It has cut in voltage. It occurs error of measurement value namely. This error, below in region diode voltage drop (0.7v) measurement value is wholesome signal, Specially, We can not get precision data. Therefore, precision level is low between theoretical and measurement data because of error in actual circuit. Conclusionally, In this paper, We define the error concerning to the power diode characteristics which is used detecting of the minute signal, and recommend the method that minimize measurement error.

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Combustion characteristics of rice-husk according to the change of heat flux (왕겨의 heat flux별 연소특성에 관한 연구)

  • Park Eun-young;Park Duckshin;Cho Youngmin;Park Byunghyun;Lee Cheulkyu
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.1190-1195
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    • 2005
  • Biomass burning is a source of greenhouse gases, carbon dioxide, methane, and nitrous oxide. Under the ideal conditions of complete combustion, the burning of biomass produces carbon dioxide and water vapor. Since complete combustion is not achieved under any conditions of biomass burning, other carbon species, including carbon monoxide, methane, non-methane hydrocarbons and particulate carbon are produced. In this study, we analyze the combustion characteristics of rice-husk, such as heat release rate, smoke production rate, the percentage variation of CO and $CO_2$, oxygen consumption rate, and mass loss under different heat fluxes (20, 50 and 70kW). As a result, at 20kW incomplete combustion is occurred so that the percentage of CO is high in initial burning and total smoke release is higher than the others. At 50kW and 70kW, the combustion behaviors is very similar except the variation of CO percentage.

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Gas Permeation Properties of Hydroxyl-Group Containing Polyimide Membranes

  • Jung, Chul-Ho;Lee, Young-Moo
    • Macromolecular Research
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    • v.16 no.6
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    • pp.555-560
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    • 2008
  • A series of hydroxyl-group containing polyimides (HPIs) were prepared in order to investigate the structure-gas permeation property relationship. Each polymer membrane had structural characteristics that varied according to the dianhydride monomers. The imidization processes were monitored using spectroscopic and thermog-ravimetric analyses. The single gas permeability of He, $H_2$, $CO_2$, $O_2$, $N_2$ and $CH_4$ were measured and compared in order to determine the effect of the polymer structure and functional -OH groups on the gas transport properties. Surprisingly, the ideal selectivity of $CO_2/CH_4$ and $H_2/CH_4$ increased with increasing level of -OH incorporation, which affected the diffusion of $H_2$ or the solubility of $CO_2$ in HPIs. For $H_2/CH_4$ separation, the difference in the diffusion coefficients of $H_2$ and $CH_4$ was the main factor for improving the performance without showing any changes in the solubility coefficients. However, the solubility coefficient of $CO_2$ in the HPIs increased at least four fold compared with the conventional polyimide membranes depending on the polymer structures. Based on these results, the polymer membranes modified with -OH groups in the polymer backbone showed favorable gas permeation and separation performance.

Process Design of Carbon Dioxide Storage in the Marine Geological Structure: II. Effect of Thermodynamic Equations of State on Compression and Transport Process (이산화탄소 해양지중저장 처리를 위한 공정 설계: II. 열역학 상태방정식이 압축 및 수송 공정에 미치는 영향 평가)

  • Huh, Cheol;Kang, Seong-Gil
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.4
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    • pp.191-198
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    • 2008
  • To design a reliable $CO_2$ marine geological storage system, it is necessary to perform numerical process simulation using thermodynamic equation of state. $CO_2$ capture process from the major point sources such as power plants, transport process from the capture sites to storage sites and storage process to inject $CO_2$ into the deep marine geological structure can be simulate with numerical modeling. The purpose of this paper is to compare and analyse the relevant equations of state including ideal, BWRS, PR, PRBM and SRK equation of state. We also studied the effect of thermodynamic equation of state in designing the compression and transport process. As a results of comparison of numerical calculations, all relevant equation of state excluding ideal equation of state showed similar compression behavior in pure $CO_2$. On the other hand, calculation results of BWRS, PR and PRBM showed totally different behavior in compression and transport process of captured $CO_2$ mixture from the oxy-fuel combustion coal-fired plants. It is recommended to use PR or PRBM in designing of compression and transport process of $CO_2$ mixture containing NO, Ar and $O_2$.

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REGULARITY AND SEMIPOTENCY OF HOM

  • Hakmi, Hamza
    • Korean Journal of Mathematics
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    • v.22 no.1
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    • pp.151-167
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    • 2014
  • Let M, N be modules over a ring R and $[M,N]=Hom_R(M,N)$. The concern is study of: (1) Some fundamental properties of [M, N] when [M, N] is regular or semipotent. (2) The substructures of [M, N] such as radical, the singular and co-singular ideals, the total and others has raised new questions for research in this area. New results obtained include necessary and sufficient conditions for [M, N] to be regular or semipotent. New substructures of [M, N] are studied and its relationship with the Tot of [M, N]. In this paper we show that, the endomorphism ring of a module M is regular if and only if the module M is semi-injective (projective) and the kernel (image) of every endomorphism is a direct summand.

The flow of $CO_{2}$ and $N_{2}$ gases through Asymmetric polytherimide Membrane

  • Park, You-In;Lee, Kew-Ho
    • Proceedings of the Membrane Society of Korea Conference
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    • 1995.09a
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    • pp.73-85
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    • 1995
  • The asymmetric hollow fiber membranes were prepared by the wet spining of polyetherimide dope solution and the effect of hollow fiber structures on the permeation characteristics of carbon dioxide and nitrogen gases through these membrane were investigated. As the concentration of the $\gamma$-butyrolactone (GBL) in dope solution, acting as a swelling agent was increased, the structure of hollow fiber was changed from the finger to sponge type. The permeabilities of gases (CO$_{2}$, N$_{2}$) through these membrane were measured over the wide range of pressure under different temperature. The effect of water vapor on the permeabilities of gases was also investigated. The measured permeabilities showed the different characteristics depending on the structure of membranes. It was found that the flow through the pores were dominant over the polymers matrix. Blocking effect by water vapor in the pores of skin layer greatly improved the ideal separation factor of carbon dioxide/nitrogen.

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Accuracy-improvement simulation of self-mixing semiconductor laser range finder driven by reshaped modulation current

  • Shinohara, Shigenobu;Nobunaga, Kazuhiko;Yoshida, Hirofumi;Ikeda, Hiroaki;Miyata, Masafumi;Nishide, Ken-ichi;Sumi, Masao
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10b
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    • pp.1021-1026
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    • 1990
  • Accuracy improvement of a self-mixing semiconductor laser range finder is predicted by simulation, in which the laser modulation current is reshaped to give an ideal triangular waveform of the optical frequency change. The maximum range measurement error of less than 0.1% in a wide range of O.1m to 1m is expected by the reshaping of the modulation current. Experimental verification of the effect of current reshaping on the linearization of the derivative of the optical frequency change curve is given.

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