• Title/Summary/Keyword: influence surface

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Characterization of the Surface Contribution to Fluorescence Correlation Spectroscopy Measurements

  • Chowdhury, Salina A.;Lim, Man-Ho
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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    • pp.583-589
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    • 2011
  • Fluorescence correlation spectroscopy (FCS) is a sophisticated and an accurate analytical technique used to study the diffusion of molecules in a solution at the single-molecule level. FCS is strongly affected by many factors such as the stability of the excitation power, photochemical processes, mismatch between the refractive indices, and variations in the cover glass thickness. We have studied FCS near the surface of a cover glass by using rhodamine 123 as a fluorescent probe and have observed that the surface has a strong influence on the measurements. The temporal autocorrelation of FCS decays with two characteristic times when the confocal detection volume is positioned near the surface of the cover glass. As the position of the detection volume is moved away from the surface, the FCS autocorrelation becomes one-component decaying; the characteristic time of the decay is the same as the faster-decaying component in the FCS autocorrelation near the surface. This observation suggests that the faster component can be attributed to the free diffusion of the probe molecules in the solution, while the slow component has its origin from the interaction between the probe molecules and the surface. We have characterized the surface contribution to the FCS measurements near the surface by changing the position of the detection volume relative to the surface. The influence of the surface on the diffusion of the probe molecules was monitored by changing the chemical properties of the surface. The surface contribution to the temporal autocorrelation of the FCS strongly depends on the chemical nature of the surface. The hydrophobicity of the surface is a major factor determining the surface influence on the free diffusion of the probe molecules near the surface.

Marine propeller integrated design Influence of manufacturing strategy on bi-dimensional foil performance

  • Martineau, J.P.;Brient, A.;Hascoet, J.Y.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.323-324
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    • 2002
  • This paper presents a preliminary study of the influence of roughness due to marine propeller blades machining on their performance. A blade surface finish that has been roughened by corrosion, cavitation and other phenomena, leads to a power penalty. Thus propellers manufacturers tend to propose blades of great surface finish, even mirror-polished. However achieving such surface finish increases manufacturing costs. With modem manufacturing means, propellers can now be machined while preserving a good surface finish. We have studied the influence of manufacturing strategy on an aspect of hydrodynamic performance, cavitation.

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The influence of heavy metal on microbial biodegradation of organic contaminants in soil (토양내의 중금속이 유기오염물질 생분해에 미치는 영향 연구)

  • 최재영;박재우
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.11a
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    • pp.196-201
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    • 2000
  • The influence of adsorption on cadmium toxicity to soil microorganisms in smectite-rich soils and sediments was quantified as a function of solution and sorbent characteristics. Adsorption and surface complexation experiments were conducted to infer Cd sorption mechanisms to a reference smectite and three fractions of a Veritsol soil, and to elucidate the effects of the surface complexation on Cd bioavailability and toxicity in soils and sediments. Cadmium adsorption isotherms conformed to the Langmuir adsorption model, with adsorptive capacities of the different samples dependent on their characteristics. Equilibrium geochemical modeling (MINTEQA2) was used to predict the speciation of Cd in the soil suspensions using Langmuir and Triple Layer surface complexation models. The influence of adsorption and surface complexation on cadmium toxicity to soil microorganisms was assessed indirectly through the relative change in microbial hydrolysis of fluorescein diacetate (FDA) as a function of total Cd concentration and sorbent characteristics. Adsorption decreased the toxicity of Cd to soil microorganisms. Inner-sphere complexation is more effective than outer-sphere complexation in reducing the bioavailability and toxicity of heavy metals in soils and sediments.

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The Influence of Surface Roughness on Thermohydrodynamic Analysis (열유체 윤활해석에 의한 표면 거칠기가 마찰거동에 미치는 영향 고찰)

  • Kim, Joon-Hyun;Kim, Seong-Keol;Kim, Joo-Hyun
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.299-304
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    • 2001
  • An approach is developed for parametric investigation of the influence of the surface roughness on thermohydrodynamic analysis with film conditions which systemically occur in journal bearings. A parametric investigation is performed for predicting the bearing behaviors such as pressure and temperature distributions in lubricating films between the stationary and moving surfaces determined by absorbed layers and interfaces on the statistical method for rough surface with Gaussian distribution. The layers expressing the effects of surface roughness are expressed as functions of the standard deviations (${\sigma}$) of each surface and surface orientation (j) to explain the flow patterns between both rough surfaces. The coupled effect of surface roughness and shear zone dependency on hydrodynamic pressure and temperature has been found by solving the present model in non-contact mode and contact mode, respectively.

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The Study of Factors that Influence the Surface Electric Field of High Voltage Planar PN Junctions (고전압 평면형 pn집합의 표면전계에 영향을 미치는 요인에 관한 고찰)

  • Park, Yearn-Ik
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.23 no.4
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    • pp.490-497
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    • 1986
  • The effectiveness of field plate and window tapering in reducing the maximum surface electric field of planar pn junctions has been studied by two dimensional computer simulation. The influence of silicon dioxide insulator thickness is also presented.

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The Influence of Pulse Frequency and Duty Factor on Surface Characteristics during Low Temperature Plasma Nitrocarburizing Treatment of Duplex Stainless Steel (Duplex Stainless Steel의 저온 플라즈마 침질탄화시 Pulse Frequency 및 Duty Factor에 따른 표면 특성평가)

  • Cheon, Chang-Seok;Lee, Insup
    • Journal of the Korean institute of surface engineering
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    • v.47 no.5
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    • pp.221-226
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    • 2014
  • A low temperature plasma nitrocarburizng was implemented on the duplex stainless steel to achieve the enhancement of surface hardness without degradation of its corrosion resistance. Attempts were made to investigate the influence of Pulse frequency and Duty factor of pulsed power in a high Pulse frequency regime on the surface characteristics of the hardened layer. The hardened layer (S-phase) was formed on all of the treated surfaces. Surface hardness reached up to 1300 $HV_{0.1}$ which is about 4.6 times higher than that of the untreated material (280 $HV_{0.1}$). The thickness of the hardened layer tends to increase lightly with the higher Pulse frequency and the higher Duty factor. The corrosion resistance of nitrocarburized duplex stainless steel was almost similar to that of the untreated material. Both the Pulse frequency and the Duty factor do not have a significant influence on the corrosion property of plasma treated duplex stainless steel.

A Study on the Influence Analysis of noise and shaking in Fishing Area of the Surface of Sea (해수면 어장에서의 소음.진동영향분석 연구)

  • 이용희;김봉익
    • Journal of Korean Port Research
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    • v.14 no.3
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    • pp.341-351
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    • 2000
  • This study is on the purpose that the influence caused by noise and shaking through construction works shall be ranged to the fishing species of fishing area of the surface of sea. This study have been performed through analysis of physical effect by the value of noise and shaking test. The resulted purpose of this study has been carried out regarding whether influence factor of the fishing species and others are related or not as per the noise and shaking. For the purpose of the survey of noise and shaking, observances have been performed regarding the direct water surface of fishing area are as well as undersea. As for this result, the influence area for the injury at the fishing area caused by the noise and shaking have been stretched out to the distance of 10km from the source of sound. In this conclusion, this study is regarded as the reference basis of the compensation of injury for the species of fish and others in fishing area.

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Influence of MAO Conditions on TiO2 Microstructure and Its Photocatalytic Activity (MAO 공정 변수가 TiO2 산화피막의 구조 및 광촉매 특성에 미치는 영향)

  • Kim, Jeong-Gon;Kang, In-Cheol
    • Journal of Powder Materials
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    • v.19 no.3
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    • pp.196-203
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    • 2012
  • $TiO_2$ was successfully formed on a Ti specimen by MAO (Micro-Arc-Oxidation) method treated in $Na_3PO_4$ electrolyte. This study deals with the influence of voltage and working time on the change of surface microstructure and phase composition. Voltage affected the forming rate of the oxidized layer and surface microstructure where, a low voltage led to a high surface roughness, more holes and a thin oxidized layer. On the other hand, a high voltage led to more dense surface structure, wider surface holes, a thick layer and fewer holes. Higher voltage increases photocatalytic activity because of better crystallization of the oxidized layer and good phase composition with anatase and rutile $TiO_2$, which is able to effectively separate excited electrons and holes at the surface.

Influence of Surface area, Surface Chemical Structure and Solution pH on the Adsorption of Pb(II) Ions on Activated Carbons

  • Goyal, Meenakshi;Amutha, R.
    • Carbon letters
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    • v.7 no.2
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    • pp.97-104
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    • 2006
  • The influence of carbon surface area, carbon-oxygen groups associated with the carbon surface and the solution pH on the adsorption of Pb(II) ions from aqueous solutions has been studied using three activated carbons. The adsorption isotherms are Type I of BET classification and the data obeys Langmuir adsorption equation. The BET surface area has little effect on the adsorption while it is strongly influenced by the presence of acidic carbon oxygen surface groups. The amount of these surface groups was enhanced by oxidation of the carbons with different oxidizing agents and reduced by eliminating these groups on degassing at different temperatures. The adsorption of Pb(II) ions increases on each oxidation and decreases on degassing the oxidized carbons. The increase in adsorption on oxidation has been attributed to the formation of acidic carbon-oxygen surface groups and the decrease to the elimination of these acidic surface groups on degassing. The adsorption is also influenced by the pH of the aqueous solution. The adsorption is only small at pH values lower than 3 but is considerably larger at higher pH values. Suitable mechanisms consistent with the adsorption data have been suggested.

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Studios on the Application of Starch for Paper Surface Sizing -The Influence of Surface Sizing Treatment with Starch on the Ink-jet Printing Property- (종이 표면 사이즈용 전분의 적용에 관한 연구 -잉크제트 인쇄품질에 미치는 영향-)

  • 윤지영;정경모;김창근;이용규
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.1
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    • pp.7-11
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    • 2002
  • The print quality of a ink jet printer is generally affected by three major components of the printing process: printer, ink formulation, and paper. The result of this study indicated that the surface sized paper with oxidized starch and cationic starch differed ink jet print quality in terms of ink spread and black optical density of the print image. Paper properties, like air permeability and siting degree, which may influence the ink jet printing were also measured. It was found that black print quality was controlled by starch level and ionic charge on the paper surface. Cationic surface sizing starch improved black ink jet print quality.