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Solid Interface (solid + interface)
Selected AbstractsTitelbild: Two-Dimensional Crystal Engineering: A Four-Component Architecture at a Liquid,Solid Interface (Angew. Chem.ANGEWANDTE CHEMIE, Issue 40 200940/2009) Vier Komponenten bilden ein supramolekulares Muster auf atomar flachem Graphit, wie S. De,Feyter et,al. in ihrer Zuschrift auf S.,7489,ff. schildern. Durch einfaches Mischen der vier Komponenten in einem konventionellen Lösungsmittel und Auftropfen auf die Oberfläche entstehen Kagomé-Gitter mit spezifisch gebundenen Templatmolekülen. Die Strukturen wurden durch Rastertunnelmikroskopie an der Flüssig-fest-Grenzfläche aufgeklärt. [source] Two-Dimensional Crystal Engineering: A Four-Component Architecture at a Liquid,Solid Interface,ANGEWANDTE CHEMIE, Issue 40 2009Jinne Adisoejoso Glückliches Zusammentreffen: Zweidimensionale Vierkomponentenkristalle wurden an einer Flüssig-fest-Grenzfläche erzeugt und durch Rastertunnelmikroskopie visualisiert. Einfaches Mischen der vier Komponenten und Aufbringen der Lösung auf die Graphit-Oberfläche führen zur spontanen Selbstorganisation der 2D-Kristalle. Bestimmte Gastmoleküle erzeugen aus dem nichtporösen Netzwerk eine poröse Struktur, indem sie innerhalb der Poren adsorbiert werden. [source] Superoleophobic Surfaces: Bioinspired Design of a Superoleophobic and Low Adhesive Water/Solid Interface (Adv. Mater.ADVANCED MATERIALS, Issue 6 20096/2009) The inside cover shows a bionic strategy to create a low-adhesive and superoleophobic interface via the oil/water/solid three-phase system, which was inspired by the antiwetting behavior of the oil droplets on the fish scales in water, as reported by Lei Jiang and co-workers on p.665. Such antiwetting behavior provides an insight into why many seabirds but few fish are killed when oil tanker spills occur. [source] Bioinspired Design of a Superoleophobic and Low Adhesive Water/Solid Interface,ADVANCED MATERIALS, Issue 6 2009Mingjie Liu The wetting/antiwetting behavior of liquid droplets on a solid surface is not an apparent or simple contact between two phases, but among three phases. Inspired by the antiwetting behavior of oil droplets on fish scales in water, a superoleophobic and low-adhesive interface is created on a solid substrate with micro/nanohierarchical structures, using oil/water/solid three-phase systems. [source] Probing the Evolution of Adsorption on Nanoporous Solids by In Situ Solid-State NMR SpectroscopyCHEMPHYSCHEM, Issue 9 2007Mingcan Xu Dr. A rotor-spinning technique is developed for carrying out in situ studies of adsorption processes by solid-state NMR spectroscopy. The method is suitable for the study of adsorption at the liquid/solid interface, does not require any modification of the NMR instrumentation, and allows spectra to be recorded immediately from the start of the adsorption process (see picture). [source] Chemical modification of pyroclastic rock by hot water: an experimental investigation of mass transport at the fluid,solid interfaceGEOFLUIDS (ELECTRONIC), Issue 1 2009J. HARA Abstract Hydrothermal water,(pyroclastic) rock interactions were examined using flow-through experiments to deduce the effect of mass transport phenomena on the reaction process. A series of experiments were conducted over the temperature range 75,250°C, with a constant temperature for each experiment, and at saturated vapour pressure, to estimate the apparent rate constants as a function of temperature. Based on the chemistry of analysed solutions, the water,rock interaction in the experiments was controlled by diffusion from the reaction surface and by the existence of a surface layer at the rock,fluid interface, which regulated the chemical reaction rate. The reaction progress depended to a high degree on flow velocity and temperature conditions, with element abundances in the fluid significantly affected by these factors. Mass transport coefficients for diffusion from the rock surface to the bulk solution have been estimated. Ca is selectively depleted under lower temperature conditions (T < 150°C), whereas Na is greatly depleted under higher temperature conditions (T > 150°C), and K reaction rates are increased when flow velocity increases. Using these conditions, specific alkali and alkali earth cations were selectively leached from mineral surfaces. The ,surface layer' comprised a 0.5,1.8 mm boundary film on the solution side (the thickness of this layer has no dependence on chemical character) and a reaction layer. The reaction layer was composed of a Si, Al-rich cation-leached layer, whose thickness was dependent on temperature, flow velocity and reaction length. The reaction layer varied in thickness from about 10,4 to 10,7 mm under high temperature/low fluid velocity and low temperature/high fluid velocity conditions, respectively. [source] Multi-linearity algorithm for wall slip in two-dimensional gap flowINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2007G. J. Ma Abstract Wall slip has been observed in a micro/nanometer gap during the past few years. It is difficult to make a mathematical analysis for the hydrodynamics of the fluid flowing in a gap with wall slip because the fluid velocity at the liquid,solid interface is not known a priori. This difficulty is met especially in a two-dimensional slip flow due to the non-linearity of the slip control equation. In the present paper we developed a multi-linearity method to approach the non-linear control equation of the two-dimensional slip gap flow. We used an amended polygon to approximate the circle yield (slip) boundary of surface shear stress. The numerical solution does not need an iterative process and can simultaneously give rise to fluid pressure distribution, wall slip velocity and surface shear stress. We analysed the squeeze film flow between two parallel discs and the hydrodynamics of a finite slider gap with wall slip. Our numerical solutions show that wall slip is first developed in the large pressure gradient zone, where a high surface shear stress is easily generated, and then the slip zone is enlarged with the increase in the shear rate. Wall slip dramatically affects generation of the hydrodynamic pressure. Copyright © 2006 John Wiley & Sons, Ltd. [source] Assessment of conservative load transfer for fluid,solid interface with non-matching meshesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 15 2005R. K. Jaiman Abstract We present a detailed comparative study of three conservative schemes used to transfer interface loads in fluid,solid interaction simulations involving non-matching meshes. The three load transfer schemes investigated are the node-projection scheme, the quadrature-projection scheme and the common-refinement based scheme. The accuracy associated with these schemes is assessed with the aid of 2-D fluid,solid interaction problems of increasing complexity. This includes a static load transfer and three transient problems, namely, elastic piston, superseismic shock and flexible inhibitor involving large deformations. We show how the load transfer schemes may affect the accuracy of the solutions along the fluid,solid interface and in the fluid and solid domains. We introduce a grid mismatching function which correlates well with the errors of the traditional load transfer schemes. We also compare the computational costs of these load transfer schemes. Copyright © 2005 John Wiley & Sons, Ltd. [source] Investigation into the Chemical Reactivity of Plasma-Deposited Perfluorophenyl Methacrylate Using Infrared Reflection Absorption Spectroscopy and Microcantilever StudiesPLASMA PROCESSES AND POLYMERS, Issue S1 2007Nuria Queralto Abstract Perfluorophenyl methacrylate (pp-PFM) was plasma-polymerized using low duty cycle conditions to yield a surface rich in active ester groups. The reactivity of this surface towards different primary amines was investigated using infrared reflection absorption spectroscopy (IRRAS) and micromechanical cantilever (MC) sensors. While IRRAS provided information on the chemistry, the MC sensors technique gave insights into volume changes induced by the reactions of the polymer film. We found that the volume change upon reaction was different for each of the amines studied and correlated this to the ability of the amines to diffuse into the polymer matrix. The changes observed can be related to reactions occurring either at the liquid,solid interface or to reactions occurring within the matrix of the polymer and appear to be related to the chemical structure of the amines. [source] Conformational changes of enzymes adsorbed at liquid, solid interface: Relevance to enzymatic activityBIOPOLYMERS, Issue 4-5 2002S. Noinville Abstract FTIR with attenuated total reflectance spectroscopy was used to study in situ adsorption of enzymes at water,solid interfaces to better understand how conformational changes may monitor enzymatic activity. Because the adsorption process depends on hydrophobic and electrostatic interactions, conformational changes were studied as a function of the nature of the adsorbing substrates, which are hydrophobic or hydrophilic in character. The adsorption kinetics of two examples of serine enzymes, ,-chymotrypsin (,-chym) and Humicola lanuginosa lipase (HLL), were studied. The secondary structure and solvation of the adsorbed enzymes were both compared to the dissolved enzymes. The positively charged ,- chym was adsorbed on a negatively charged hydrophilic support with minor structural changes, but the negatively charged lipase had no affinity for a similar support. Both enzymes were strongly retained on the hydrophobic support. The secondary and tertiary structures of the ,-chym adsorbed on the hydrophobic support were strongly altered, which correlates to the inhibition of enzymatic hydrolysis. The specific solvation obtained for the adsorbed HLL is consistent with the existence of the open conformer in relation to the enhanced enzymatic activity at the water,hydrophobic interface. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 323,326, 2002 [source] Ensemble Measurement of Diffusion: Novel Beauty and EvidenceCHEMPHYSCHEM, Issue 15 2009Christian Chmelik Dr. Abstract Recording the evolution of concentration profiles in nanoporous materials opens a new field of diffusion research with particle ensembles. The technique is based on the complementary application of interference microscopy and IR micro-imaging. Combining the virtues of diffusion measurements with solids and fluids, it provides information of unprecedented wealth and visual power on transport phenomena in molecular ensembles. These phenomena include the diverging uptake and release patterns for concentration-dependent diffusivities, the mechanisms of mass transfer at the fluid,solid interface and opposing tendencies in local and global concentration evolution. [source] Quadratic programming algorithm for wall slip and free boundary pressure conditionINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2006C. W. Wu Abstract Wall slip is often observed in a highly sheared fluid film in a solid gap. This makes a difficulty in mathematical analysis for the hydrodynamic effect because fluid velocity at the liquid,solid interfaces is not known a priori. If the gap has a convergent,divergent wedge, a free boundary pressure condition, i.e. Reynolds pressure boundary condition, is usually used in the outlet zone in numerical solution. This paper, based on finite element method and parametric quadratic programming technique, gives a numerical solution technique for a coupled boundary non-linearity of wall slip and free boundary pressure condition. It is found that the numerical error decreases with the number of elements in a negative power law having an index larger than 2. Our method does not need an iterative process and can simultaneously gives rise to fluid film pressure distribution, wall slip velocity and surface shear stress. Wall slip always decreases the hydrodynamic pressure. Large wall slip even causes a null hydrodynamic pressure in a pure sliding solid gap. Copyright © 2005 John Wiley & Sons, Ltd. [source] Excited-state molecular structures captured by X-ray transient absorption spectroscopy: a decade and beyondACTA CRYSTALLOGRAPHICA SECTION A, Issue 2 2010Lin X. Chen Transient molecular structures along chemical reaction pathways are important for predicting molecular reactivity, understanding reaction mechanisms, as well as controlling reaction pathways. During the past decade, X-ray transient absorption spectroscopy (XTA, or LITR-XAS, laser-initiated X-ray absorption spectroscopy), analogous to the commonly used optical transient absorption spectroscopy, has been developed. XTA uses a laser pulse to trigger a fundamental chemical process, and an X-ray pulse(s) to probe transient structures as a function of the time delay between the pump and probe pulses. Using X-ray pulses with high photon flux from synchrotron sources, transient electronic and molecular structures of metal complexes have been studied in disordered media from homogeneous solutions to heterogeneous solution,solid interfaces. Several examples from the studies at the Advanced Photon Source in Argonne National Laboratory are summarized, including excited-state metalloporphyrins, metal-to-ligand charge transfer (MLCT) states of transition metal complexes, and charge transfer states of metal complexes at the interface with semiconductor nanoparticles. Recent developments of the method are briefly described followed by a future prospective of XTA. It is envisioned that concurrent developments in X-ray free-electron lasers and synchrotron X-ray facilities as well as other table-top laser-driven femtosecond X-ray sources will make many breakthroughs and realise dreams of visualizing molecular movies and snapshots, which ultimately enable chemical reaction pathways to be controlled. [source] Conformational changes of enzymes adsorbed at liquid, solid interface: Relevance to enzymatic activityBIOPOLYMERS, Issue 4-5 2002S. Noinville Abstract FTIR with attenuated total reflectance spectroscopy was used to study in situ adsorption of enzymes at water,solid interfaces to better understand how conformational changes may monitor enzymatic activity. Because the adsorption process depends on hydrophobic and electrostatic interactions, conformational changes were studied as a function of the nature of the adsorbing substrates, which are hydrophobic or hydrophilic in character. The adsorption kinetics of two examples of serine enzymes, ,-chymotrypsin (,-chym) and Humicola lanuginosa lipase (HLL), were studied. The secondary structure and solvation of the adsorbed enzymes were both compared to the dissolved enzymes. The positively charged ,- chym was adsorbed on a negatively charged hydrophilic support with minor structural changes, but the negatively charged lipase had no affinity for a similar support. Both enzymes were strongly retained on the hydrophobic support. The secondary and tertiary structures of the ,-chym adsorbed on the hydrophobic support were strongly altered, which correlates to the inhibition of enzymatic hydrolysis. The specific solvation obtained for the adsorbed HLL is consistent with the existence of the open conformer in relation to the enhanced enzymatic activity at the water,hydrophobic interface. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 323,326, 2002 [source] Pesticide soil sorption parameters: theory, measurement, uses, limitations and reliability,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 5 2002R Don Wauchope Abstract The soil sorption coefficient Kd and the soil organic carbon sorption coefficient KOC of pesticides are basic parameters used by environmental scientists and regulatory agencies worldwide in describing the environmental fate and behavior of pesticides. They are a measure of the strength of sorption of pesticides to soils and other geosorbent surfaces at the water/solid interface, and are thus directly related to both environmental mobility and persistence. KOC is regarded as a ,universal' parameter related to the hydrophobicity of the pesticide molecule, which applies to a given pesticide in all soils. This assumption is known to be inexact, but it is used in this way in modeling and estimating risk for pesticide leaching and runoff. In this report we examine the theory, uses, measurement or estimation, limitations and reliability of these parameters and provide some ,rules of thumb' for the use of these parameters in describing the behavior and fate of pesticides in the environment, especially in analysis by modeling. © 2002 Society of Chemical Industry [source] | ||||||||||||||||