• Membrane and Water Treatment
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• v.15 no.1
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• pp.31-39
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• 2024

The flow in a nanopore of filtration membrane is often multiscale and consists of both the adsorbed layer flow and the intermediate continuum fluid flow. There is a controversy on which interface the slippage should occur in the nanopore filtration: On the adsorbed layer-pore wall interface or on the adsorbed layer-continuum fluid interface? What is the difference between these two slippage effects? We address these subjects in the present study by using the multiscale flow equations incorporating the slippage on different interfaces. Based on the limiting shear strength model for the slippage, it was found from the calculation results that for the hydrophobic pore wall the slippage surely occurs on the adsorbed layer-pore wall interface, however for the hydrophilic pore wall, the slippage can occur on either of the two interfaces, dependent on the competition between the interfacial shear strength on the adsorbed layer-pore wall interface and that on the adsorbed layer-continuum fluid interface. Since the slippage on the adsorbed layer-pore wall interface can be designed while that on the adsorbed layer-continuum fluid interface can not, the former slippage can result in the flux through the nanopore much higher than the latter slippage by designing a highly hydrophobic pore wall surface. The obtained results are of significant interest to the design and application of the interfacial slippage in nanoporous filtration membranes for both improving the flux and conserving the energy cost.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.15-19
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• 2006

A ferredoxin adsorbed hetero self-assembled layer was fabricated on chemically modified Au substrate, 4-Aminothiophenol (4-ATP) was deposited onto Au substrate and then N-succinimidyl-3-[2-pyridyldithio] propionate (SPDP) was adsorbed on the 4-ATP layer, since SPDP was used as a bridging molecule for ferredoxin adsorption, Ferredoxin/SPDP/4-ATP structured hetero layer was constructed because of strong chemical binding of ferredoxin, SPDP, and 4-ATP, The surface of the ferredoxin-adsorbed SPDP/4-ATP layer was observed by scanning tunneling microscopy, The hetero film formation was verified by surface plasmon resonance measurement. The current flow and rectifying property based on the scanning tunneling spectroscopy I-V characteristics was achieved in the proposed hetero layer. Thus, the hetero layer structure of ferredoxin functioned as a molecular diode with rectifying property, The proposed molecular diode can be usefully applied for the development of molecular scale electronic devices.

• Journal of the Korean Chemical Society
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• v.17 no.2
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• pp.80-84
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• 1973

In treating solid-liquid interfaces, it is assumed that the adsorbed layer consists of monolayer and the molecules of the adsorbed layer behave as two dimensional liquid and oscillate harmonically in the vertical direction to the adsorbent. Applying the transition state theory of significant liquid structure to the adsorbed molecules, the adsorption isotherm, entropy and heat of adsorption for cyclohexane-benzene solutions adsorbed on silica-gel G are calculated. The calculated values are in good agreements with those of the observed ones.

• Membrane and Water Treatment
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• v.13 no.4
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• pp.167-172
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• 2022

The analytical results are presented for the mass transfer in a cylindrical pore covering from the macroscale, multiscale to nanoscale owing to the variation of the inner diameter of the pore. When the thickness h_bf of the physically adsorbed layer potentially fully formed on the pore wall is comparable to but less than the inner radius R₀ of the pore, the multiscale flow occurs consisting of both the nanoscale non-continuum adsorbed layer flow and the macroscopic continuum liquid flow; When R₀ ≤ h_bf, the flow in the whole pore is essentially non-continuum; When R₀ is far greater than h_bf, the flow in the whole pore can be considered as macroscopic and continuum and the adsorbed layer effect is negligible.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.735-739
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• 2005

Presented is a voltammetric study of co-adsorption of irreversibly adsorbing Sb and Te on Pt(111). When a layer of Sb and Te was formed via simultaneous adsorption, the reduction peak of Te was observed at 0.30 V in the initial cathodic scan. In contrast, sequential adsorption of Sb followed by Te adsorption led to a Te reduction peak at 0.50 V in the initial scan. As the voltammetric scan was continued, in addition, the voltammogram of the simultaneously co-adsorbed layer changed, while that of the sequentially co-adsorbed layer did not. These observations are discussed in terms of formation of a homogeneously mixed layer and a layer consisting of heterogeneously separated domains of Sb and Te. Also, the difference in the adsorption strength of Sb and Te was observed.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.213-218
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• 2006

Meniscus, adsorbed layer thickness, capillary pressure and disjoining pressure was deduced in extended meniscus region in cement paste pore by hydrostatic equilibrium. From the results, the relationship between pore size and adsorbed layer thickness could be derived and adsorbed layer thickness represents $0.299{\sim}2.700nm$ according to pore size $1nm{\sim}1{\mu}m$. Especially, disjoining pressure rapidly Increased in less than 10 nm pore size according to adsorbed layer thickness. Therefore, it is interpreted that autogenous shrinkage of cement paste is highly increases in formation of less than 10 nm pore size. Predictions of autogenous shrinkage in cement paste considering driving force for autogenous shrinkage with capillary pressure and disjoining pressure was low in comparison with experiment values between $1{\sim}4$ days and high in later period. These tendency could be thought that pore damage by mercury injection in early age makes shrinkage driving force underestimate and assumption for unsaturated independent pore makes overestimate. These interactions might be needed corrections considering on hydration or pore replacement model.

• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1011-1016
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• 2002

Colloidal particles of silica (100 nm in size) were electrostatically dispersed and adsorbed on a glass substrate coated with silica sol or alumina sol. Stability of the suspensions and microstructure of the adsorbed particle layers were discussed in terms of total potential energies between the particles and the substrate. Well-dispersed suspension resulted in a layer with densely packed and regularly arranged particles, whereas less stable suspension resulted in a porous layer with loosely packed and irregularly arranged particles. Despite repulsive interactions between the particles and the substrate coated with silica sol, the observed adsorption can be attributed to chemical bonds formed at the interface between the particle and silica sol. In contrast, the adsorption of the particles on the substrate coated with alumina sol formed a layer with strongly adhered and densely packed particles, due to large attractive interactions between the particles and alumina sol.

• Bulletin of the Korean Chemical Society
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• v.8 no.5
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• pp.358-362
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• 1987

The interaction of oxygen with polycrystalline nickel surface has been studied by investigating the X-ray photoelectron spectra of O 1s, Ni $2p_{3/2}$, and their valence band electrons. By comparing the oxygen exposure of this work with the reported results of LEED, AES, and work function measurements, it is found that the atomic oxygen, adsorbed dissociatively in the initial stage of exposure, is responsible for a p(2 ${\times}$ 2) structure and a subsequent c(2 ${\times}$ 2) structure on the Ni(100) surface. This dissociatively adsorbed oxygen species forms surface NiO layer subsequently on further oxygen exposure. The NiO layer is more easily formed with the increasing temperature. Non-stoichiometric oxygen species is also found to accompany the NiO layer. It appears prior to the formation of bulk NiO at all of the temperatures of this work except at 523K.

• Bulletin of the Korean Chemical Society
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• v.16 no.12
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• pp.1229-1232
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• 1995

• Journal of the Korean Chemical Society
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• v.21 no.5
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• pp.353-361
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• 1977

In this paper we propose a new theory of multilayer physical adsorption based on the view that a second or higher layer molecule will be adsorbed above the center of a square or triangular array of molecules, rather than on top of molecules themselves, in the next lower layer and the corresponding adsorption isotherm is derived. The derived isotherm contains three adjustable parameters; $v_m$ (monolayer capacity), q/$q_1$ (ratio of the molecular partition function for the second or higher layer vs. that for the first layer) and n (a parameter characterizing the piling pattern of adsorbed molecules). When applied to adsorption of argon on "Carbolac" carbon and nitrogen on Linde silica, excellent agreements between observed and calculated values are obtained up to p/$p_0$ = 0.8. In both cases n = 3 gives the best fit and this probably indicates that adsorbed molecules are piled up in a closest packing pattern.