• 제목/요약/키워드: decay property

검색결과 76건 처리시간 0.029초

Sputter etching에 의한 각종 섬유의 대전방지에 관한 연구 (A Study of Anti-Static Property of Several Fibers Treated with Sputter Etching)

  • Kim, Yong Hae;Koo, Bon Sik;Cho, Yeun Chung;Koo, Kang;Son, Tae Won
    • 한국염색가공학회지
    • /
    • 제9권6호
    • /
    • pp.10-17
    • /
    • 1997
  • In order to improve the anti-static property of several hydrophobic fibers by sputter etching, polyester, polypropylene and poly(p-phenylene sulfide) have been etched by sputtering in the presence of argon gas and the resulting anti-static property investigated by half time decay, the time of water permeation, weight loss rate and scanning electron microscope(SEM). The temporary change and durability of anti-static property of samples treated with sputter etching were evaluated. The results were as follows; 1) Half time decay of samples treated with sputter etching were decreased about 18~38%. According to increasing sputter etching time, half time decay is decreased. 2) The wettability and weight loss rate of treated samples were increased remarkably. According to the SEM photographs, many microcraters on the substrate surface by the sputter etching were observed. 3) Although the washing treatment and the time elapsed after treatment are allowed longer, the variation of half time decay hardly can find.

  • PDF

초전도자석의 영구전류모드 운전시 초기자장감쇠 (The Initial Magnetic Field Decay of the Superconducting Magnet in the Persistent Current Mode)

  • 배준환;심기덕;권영길
    • 한국초전도ㆍ저온공학회논문지
    • /
    • 제2권1호
    • /
    • pp.31-34
    • /
    • 2000
  • this paper deals with the initial magnetic field decay for a large scale superconducting magnet e.g. NMR/MRI magnet. The high resolution image can not be obained during the periods of the initial field decay. It is known that all superconducting materials have the property of diamagnetism. This diamagnetism is usually explained with the concept of screening current. We assumed that the existence of the screening currebt. we assumed that the existence of the screening current makes the current distribution in the superconducting wire non-uniform. And the initial magnetic field decay is caused steady current state in the view of its pattern. The initial magnetic field decay is caused by the change of the current distribution between the energizing state and persistent current mode. in this paper the theoretical analysis for the current distributions has been introduced for each state. The experiments have been carried out to verify transport currents in order to veperiments, it small at the higher transport current.

  • PDF

플라즈마 처리된 PET 필름의 표면분석에 관한 연구 (A Study on the Surface Analysis of Plasma-Treated PET Film)

  • 임경범;최훈영;이석현;이덕출
    • 대한전기학회논문지:전기물성ㆍ응용부문C
    • /
    • 제53권12호
    • /
    • pp.596-600
    • /
    • 2004
  • In this study, the surface properties of PET film were analyzed after plasma surface treatment. After plasma treatment of surface roughness and XPS were evaluated to analyze the chemical property, while the surface potential decay and surface resistance rate was measured to analyze the electric관 characteristic. When plasma discharge treatment was conducted for less than 10 minutes, the electrical insulating property was improved by evaporation of low molecular weight materials and cleaning of surface. However, when the treatment was conducted for more than 10 minutes, the insulating property was decreased due to excessive discharge energy. Analyses of chemical characteristics showed that 10-minute treatment resulted in increase of C-O and O=C-O bonds. However, when treated for more than 10 minutes. they were relatively decreased.

A CONSERVATIVE NONLINEAR DIFFERENCE SCHEME FOR THE VISCOUS CAHN-HILLIARD EQUATION

  • Choo, S.M.;Chung, S.K.
    • Journal of applied mathematics & informatics
    • /
    • 제16권1_2호
    • /
    • pp.53-68
    • /
    • 2004
  • Numerical solutions for the viscous Cahn-Hilliard equation are considered using the Crank-Nicolson type finite difference method which conserves the mass. The corresponding stability and error analysis of the scheme are shown. The decay speeds of the solution in $H^1-norm$ are shown. We also compare the evolution of the viscous Cahn-Hilliard equation with that of the Cahn-Hilliard equation numerically and computationally, which has been given as an open question in Novick-Cohen[13].

ASYMTOTIC BEHAVIOUR OF THE VISCOUS CAHN-HILLIARD EQUATION

  • Choo, S.M.;Chung, S.K.
    • Journal of applied mathematics & informatics
    • /
    • 제11권1_2호
    • /
    • pp.143-154
    • /
    • 2003
  • Analytical solutions for the viscous Cahn-Hilliard equation are considered. Existence and uniqueness of the solution are shown. The exponential decay of the solution in H$^2$-norm, which is an improvement of the result in Elliott and Zheng[5]. We also compare the early stages of evolution of the viscous Cahn-Hilliard equation with that of the Cahn-Hilliard equation, which has been given as an open question in Novick-Cohen[8].

플라즈마처리에 따른 에폭시 복합재료의 표면특성 (Surface Properties of Epoxy Composites by Plasma Treatment)

  • 임경범;이백수;이덕출
    • 한국전기전자재료학회논문지
    • /
    • 제14권10호
    • /
    • pp.821-827
    • /
    • 2001
  • In this study performed to identify a degradation mechanism in macromolecular insulating material, the contact angel, surface potential decay, surface resistivity, and XPS analysis were compared after exposure of FRP laminate to plasma discharge. In the case of contact angle, the surface of specimen untreated showed weak hydrophobic property of 73。. However, the contact angle was decreased to 20。in the plasma-treated specimen. In the case of chemical changes arising form plasma treatment, carboxl radicals were generated mainly in the surface treated, which was rapidly changed to the hydrophilic one. In the corona potential decay study to determine the electrical changes of the surface, positive charges were rapidly decreased when compared with negative charges, leading to negative property in the surface of specimen not treated. However, in the case of the hydrophilic surface, lots of carboxl radicals acting as positive polarity were generated, resulting in positive surface. Owing to such positive surface, charges of negative polarity applied were rapidly decreased.

  • PDF

NECESSARY CONDITION AND SUFFICIENT CONDITION FOR THE WAVELET FRAMES IN $L^2(R^n)$

  • Wu, Guochang;Zhang, Rui
    • Journal of applied mathematics & informatics
    • /
    • 제28권5_6호
    • /
    • pp.1117-1130
    • /
    • 2010
  • The main goal for this paper is consider the necessary conditions and sufficient conditions of wavelet frames in higher dimensions with an arbitrary expanding matrix dilation. At first, we give a necessary condition of wavelet frame in $L^2(R^n)$, which generalizes the univariate results of Shi from one dimension with an arbitrary real number a(a > 1) dilation to higher dimension with an arbitrary expansive matrix dilation. Secondly, we deduce a necessary condition for wavelet frames in $L^2(R^n)$ when the function $\psi$ satisfies some property of the decay. For the case n = 1, we obtain a corollary which has weaker condition comparing with existing result.

XPS와 표면전위감소 통한 PET 필름의 표면분석 (Surface analysis of PET films by XPS and surface potential decay)

  • 임겸범;유도현;이붕주;이백수;이상희;신태현;신백균;이덕출
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2004년도 하계학술대회 논문집 C
    • /
    • pp.1682-1684
    • /
    • 2004
  • In this study, the surface properties of PET film were analyzed after plasma surface treatment. After plasma treatment of surface roughness and XPS were evaluated to analyze the chemical property, while the surface potential decay and surface resistivity was measured to analyze the electrical characteristic. When plasma discharge treatment was conducted for less than 10 minutes, the electrical insulating property was found to be improved through evaporation of low molecular weight materials and cleaning of surface. However, when the treatment was conducted for more than 10 minutes, the insulating property was decreased due to excessive discharge energy. Analysis of chemical characteristics showed that 10-minute treatment resulted in increase of C-O and O=C-O. However, when treated for more than 10 minutes, they were relatively decreased.

  • PDF

나노크기의 매연입자에 대한 LII의 열-물질 전달 모델에 관한 수치적 연구 (A Numerical Study of Heat and Mass Transfer Model of LII for Nanoscale Soot Particles)

  • 김규보;심재영;장영준;전충환
    • 대한기계학회논문집B
    • /
    • 제31권7호
    • /
    • pp.596-603
    • /
    • 2007
  • As increasing interest for soot emission. etc in combustion systems, various studies are being carried out for the reduction and measurement techniques of soot. Especially, laser induced incandescence is the useful measurement technique which has distinguished spatial and temporal resolution for primary particle size, volume fraction and aggregated particle size etc. Time resolved laser induced incandescence is the technique for measuring primary particle size that is decided to solve the signal decay rate which is related to the cooling behavior of heated particle by pulsed laser. The cooling behavior of heated particle is able to represent the heat and mass transfer model which are involved constants of soot property for surround gas temperature on the our previous work. In this study, it is applied to the time-dependence thermodynamic properties for soot temperature instead of constants of soot property for surround gas temperature and compared two different model results.