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Chan, Chi-Ming, Lu-Tao Wang i Lin Li. "Applications of Surface Analysis Techniques in Surface Characterization of Polymer Surfaces and Interfaces". Journal of The Adhesion Society of Japan 38, nr 5 (2002): 173–92. http://dx.doi.org/10.11618/adhesion.38.173.
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Chen, Xiaobin, Jiasheng Zhang, Yuanjie Xiao i Jian Li. "Effect of roughness on shear behavior of red clay – concrete interface in large-scale direct shear tests". Canadian Geotechnical Journal 52, nr 8 (sierpień 2015): 1122–35. http://dx.doi.org/10.1139/cgj-2014-0399.
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Few studies have focused on evaluating regular surface roughness and its effect on interfacial shear behavior of the red clay – concrete interface. This paper presents the results of a series of laboratory large-scale direct shear tests conducted using different types of red clay – concrete interfaces. The objective is to examine the effect of surface roughness on these types of soil–concrete interfaces. In the smooth-interface tests, the measured peak and residual shear strength values are very close to each other, with no observed shear dilation. The surface roughness is found to have a remarkable effect on the interfacial shear strength and shear behavior, with the shear strength increasing with increased surface roughness level. The shear dilation is likely to occur on rougher interfaces under lower confining pressure due to the behavior of compressed clay matrices. Owing to the clay matrix’s cohesion and friction, the interfacial shear strength on rough interfaces consists of cohesive and frictional forces between the clay and concrete surfaces. The friction angle value is observed to fluctuate between the clay’s friction angle and the smooth interface’s friction angle. This can be related to the position change of the shear failure slip plane. The confining pressure and surface roughness could change the shear failure plane’s position on the interface. Furthermore, the red clay – structure interface is usually known as the weakest part in the mechanical safety assessment.
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Marecek, Vladim^ ^iacute;r. "Surface Layers at the Polarized Liquid/Liquid Interfaces". Review of Polarography 60, nr 1 (2014): 17–24. http://dx.doi.org/10.5189/revpolarography.60.17.
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Robinson, I. K. "Surface Structural Techniques Applied to Interfaces". MRS Bulletin 15, nr 9 (wrzesień 1990): 38–41. http://dx.doi.org/10.1557/s0883769400062436.
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An interface is an internal surface, the boundary between two media which may be crystalline, amorphous solid, or liquid. Its close similarity with a surface, a solid-vacuum boundary, suggests that many of the powerful techniques available for studying surfaces might be applied to the interface structure problem. The extent to which this is possible is the subject of this article.The techniques to be discussed in this article include low energy electron diffraction (LEED), medium energy ion scattering (MEIS), x-ray diffraction, and x-ray reflectivity. (The most widely used method, transmission electron microscopy (TEM), is the subject of a separate article in this issue of the MRS BULLETIN.) To summarize what we will find, surface methods were developed to be nonpenetrating in order to have surface sensitivity. This works against us in the interface situation by requiring the use of extremely thin samples, at least on one side of the interface. This means special handling of samples in some cases and raises the possibility of artifac-tual results. Of the three methods, x-ray diffraction is the most penetrating and least surface sensitive; it probably has the greatest potential for widespread use in interface science.This article defines structure as “atomic structure” for this purpose: we are interested in the coordinates of atoms at the interface and their relation to bulk structures on one or both sides. For this reason, we will consider only interfaces that are crystalline on at least one side. Since crystals are by far our strongest structural reference point, much less can be said about other interfaces. We will also consider the morphology of an interface, defined as the boundary of the crystal(s) that demarcates the interface, also at the atomic level. This is most apparent in the form of interface roughness. The roles of strain and misfit dislocations in interface formation, also studied by these techniques, are outside the scope of this article.
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Li, Junbai, i Krister Holmberg. "Surface chemistry and interface science". Physical Chemistry Chemical Physics 19, nr 35 (2017): 23568–69. http://dx.doi.org/10.1039/c7cp90152f.
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Weidner, Elizabeth, i Thomas C. Weber. "Broadband acoustic characterization of backscattering from a rough stratification interface". Journal of the Acoustical Society of America 155, nr 1 (1.01.2024): 114–27. http://dx.doi.org/10.1121/10.0024148.
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Broadband acoustic analysis of scattering from sharp density gradients in the water column generally treat the interfaces as smooth surfaces. However, these interfaces may exhibit roughness owing to external water column forcing and local convective processes. In this work we extend broadband backscatter analysis methods to consider interface roughness by drawing upon methods developed for sea surface and seabed acoustic backscattering. The one-dimensional acoustic model from Weidner and Weber [J. Acoust. Soc. Am. 150(6), 4353–4361 (2021)], which predicts a decay in the reflected wave amplitude from stratification interfaces with increasing frequency, was expanded for surface applications. The expanded model was used to analyze the scattered pressure field from interfaces over a range of surface roughness magnitudes. Analysis of model results indicate that stratification interface roughness, quantified by the root-mean-squared interface slope angle and root-mean-squared height of the interface, modifies the model-predicted frequency-dependent backscattering. A broadband acoustic inversion procedure to remotely measure the magnitude of the vertical extent of stratification gradients and the corresponding sound speed perturbation was defined. The broadband inversion method was tested on data collected in the Baltic Sea with well-documented, strong salinity-driven stratification.
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Robinson, I. K. "Surface diffraction on semiconductor surfaces and interfaces". Applied Surface Science 56-58 (styczeń 1992): 117–22. http://dx.doi.org/10.1016/0169-4332(92)90224-l.
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You, Hoydoo, i Zoltán Nagy. "Applications of Synchrotron Surface X-Ray Scattering Studies of Electrochemical Interfaces". MRS Bulletin 24, nr 1 (styczeń 1999): 36–40. http://dx.doi.org/10.1557/s088376940005171x.
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Aqueous-solution/solid interfaces are ubiquitous in modern manufacturing environments as well as in our living environment, and studies of such interfaces are an active area of science and engineering research. An important area is the study of liquid/solid interfaces under active electrochemical control, which has many immediate technological implications, for example, corrosion/passivation of metals and energy storage in batteries and ultracapacitors. The central phenomenon of electrochemistry is the charge transfer at the interface, and the region of interest is usually wider than a single atomic layer, ranging from a monolayer to thousands of angstroms, extending into both phases.Despite the technological and environmental importance of liquid/solid interfaces, the atomic level understanding of such interfaces had been very much hampered by the absence of nondestructive, in situ experimental techniques. The situation has changed somewhat in recent decades with the development of the largely ex situ ultrahigh vacuum (UHV) surface science, modern spectroscopic techniques, and modern surface microscopy.However in situ experiments of electrochemical interfaces are difficult, stemming from the special nature of these interfaces. These are so-called buried interfaces in which the solid electrode surface is covered by a relatively thick liquid layer. For this reason, the probe we use in the structural investigation must satisfy simultaneously two conditions: (1) the technique must be surface/interface sensitive, and (2) absorption of the probe in the liquid phase must be sufficiently small for penetration to and from the interface of interest without significant intensity loss.
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Li, Huanhuan, Zhigang Meng i Songlin Shen. "Effects of Interface Morphology on the Shear Mechanical Properties of Sand–Concrete Interfaces". Materials 16, nr 18 (8.09.2023): 6122. http://dx.doi.org/10.3390/ma16186122.
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The morphology of the contact surface between cast-in-place engineering structures and soil is generally random. Previous research focusing on the shear mechanical properties of soil–concrete interfaces has predominantly concentrated on the role of interface roughness by constructing regular concrete surface types, largely neglecting the potential impact of the roughness morphology (i.e., the morphology of the concrete surface). In this study, concrete blocks with the same interface roughness and different roughness morphologies were constructed based on the sand-cone method, including random rough surface, triangular groove surface, rectangular groove surface, trapezoid groove surface, and semicircular groove surface. A series of direct shear tests were conducted on the rough and smooth sand–concrete interfaces, as well as on natural sand. Through these tests, we examined the shear mechanical behavior and strength of the sand–concrete interfaces, and analyzed the underlying shear mechanisms. The results showed that: (i) the interface morphology had little effect on the variation in the shear stress–displacement curve of sand–concrete interfaces, and it had a significant influence on the shear strength of the interfaces; (ii) under the same normal stress, the shear strength of the sand–concrete interfaces with a random rough surface was the greatest, followed by the triangular groove surface, while the shear strength of the rectangular groove surface proved the lowest; (iii) the shear strength of the sand–concrete interfaces with the same roughness was affected by the size of the contact area between the concrete plane and the sand, that is, a larger contact area correlated with a decrease in shear strength. It can be concluded that the shear strength value of a sand–concrete surface with the triangular groove is the closest to the shear strength of a random rough interface. By gaining a deep understanding of the effects of different contact surface morphologies on shear strength and shear behavior, significant insights can be provided for optimizing engineering design and enhancing engineering performance.
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Zhang, Hengzhong, i Jillian F. Banfield. "Phase transformation of nanocrystalline anatase-to-rutile via combined interface and surface nucleation". Journal of Materials Research 15, nr 2 (luty 2000): 437–48. http://dx.doi.org/10.1557/jmr.2000.0067.
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The kinetics of phase transformation of nanocrystalline anatase samples was studied using x-ray diffraction at temperatures ranging from 600 to 1150 °C. Kinetic data were analyzed with an interface nucleation model and a newly proposed kinetic model for combined interface and surface nucleation. Results revealed that the activation energy of nucleation is size dependent. In anatase samples with denser particle packing, rutile nucleates primarily at interfaces between contacting anatase particles. In anatase samples with less dense particle packing, rutile nucleates at both interfaces and free surfaces of anatase particles. The predominant nucleation mode may change from interface nucleation at low temperatures to surface nucleation at intermediate temperatures and to bulk nucleation at very high temperatures. Alumina particles dispersed among the anatase particles can effectively reduce the probability of interface nucleation at all temperatures.
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LI, YONG-DONG, i KANG-YONG LEE. "SIZE-DEPENDENT BEHAVIOR OF LOVE WAVE PROPAGATION IN A NANOCOATING". Modern Physics Letters B 24, nr 31 (20.12.2010): 3015–23. http://dx.doi.org/10.1142/s0217984910025346.
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The effect of surface/interface stress on mechanical behaviors may become remarkable when the characteristic size of a structure decreases to nanoscale. Various problems have been analyzed to reveal the size-dependent mechanical behaviors of nano structures with curved surfaces/interfaces. In this work, the problem of planar surfaces/interfaces is addressed. The generalized Young–Laplace equation is presented for a planar interface and the propagation behavior of Love wave in a nanocoating is discussed. Parametric studies indicate that if the surface effect of the nanocoating is considered the phase velocity of Love wave shows notable size-dependency on both the nanocoating thickness and the wavelength. When these two sizes are both in nanoscale, the phase velocity further depends on the relative size between them. In addition, increasing the residual surface stress may reduce the phase velocity of Love wave.
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Chang, Boyce, Andrew Martin, Paul Gregory, Souvik Kundu, Chuanshen Du, Millicent Orondo i Martin Thuo. "Functional Materials through Surfaces and Interfaces". MRS Advances 3, nr 37 (2018): 2221–33. http://dx.doi.org/10.1557/adv.2018.399.
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ABSTRACTIn most materials, surfaces and interfaces present a significant portion of the workable area, but this area has often been erroneously perceived as a challenge in processing and thus, largely ignored. Surfaces and interfaces, however, present a network of energetically mismatched (sometimes metastable) molecules that can be exploited to either control surface reactions, engineer bulk stability or reveal new fundamental details of otherwise not well understood processes or systems as described herein. This perspective captures the role of i) structure, ii) chemistry and iii) thermodynamics at the interface in fabricating functional materials. Engineering substrate morphology enables tunable wettability either through the substrate or an adsorbed self-assembled monolayer (SAM), the latter being largely due to effect of sub-nanoscale roughness on conformational defects and overall order in the SAM. Surface roughness and chemistry also dictates the nature and amount of adventitious contaminants on a surface, and this was used to control volume of adsorbed water leading to controlled and tunable step-growth polymerization. The chemical treatment renders the paper amphiphobic, which could be used for self-cleaning surfaces and nucleation of water microdroplets for water harvesting. Finally, creating a self-passivating polished thin (∼0.7-2 nm) shell on a molten metal microdroplet kinetically frustrates solidification leading to significant undercooling. The ambient undercooled liquid metal is used for mechanically-triggered heat-free solder and smart composites. These three cases demonstrate key aspects of surface and interface engineering in integrating well-known concepts for the development of functional materials.
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Gowda, Arun, David Esler, Sandeep Tonapi, Annita Zhong, K. Srihari i Florian Schattenmann. "Micron and Submicron-Scale Characterization of Interfaces in Thermal Interface Material Systems". Journal of Electronic Packaging 128, nr 2 (14.02.2006): 130–36. http://dx.doi.org/10.1115/1.2188952.
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One of the key challenges in the thermal management of electronic packages are interfaces, such as those between the chip and heat spreader and the interface between a heat spreader and heat sink or cold plate. Typically, thermal interfaces are filled with materials such as thermal adhesives and greases. Interface materials reduce the contact resistance between the mating heat generating and heat sinking units by filling voids and grooves created by the nonsmooth surface topography of the mating surfaces, thus improving surface contact and the conduction of heat across the interface. However, micron and submicron voids and delaminations still exist at the interface between the interface material and the surfaces of the heat spreader and semiconductor device. In addition, a thermal interface material (TIM) may form a filler-depleted and resin-rich region at the interfaces. These defects, though at a small length scale, can significantly deteriorate the heat dissipation ability of a system consisting of a TIM between a heat generating surface and a heat dissipating surface. The characterization of a freestanding sample of TIM does not provide a complete understanding of its heat transfer, mechanical, and interfacial behavior. However, system-level characterization of a TIM system, which includes its freestanding behavior and its interfacial behavior, provides a more accurate understanding. While, measurement of system-level thermal resistance provides an accurate representation of the system performance of a TIM, it does not provide information regarding the physical behavior of the TIM at the interfaces. This knowledge is valuable in engineering interface materials and in developing assembly process parameters for enhanced system-level thermal performance. Characterization of an interface material between a silicon device and a metal heat spreader can be accomplished via several techniques. In this research, high-magnification radiography with computed tomography, acoustic microscopy, and scanning electron microscopy were used to characterize various TIM systems. The results of these characterization studies are presented in this paper. System-level thermal performance results are compared to physical characterization results.
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Braski, D. N., i K. B. Alexander. "Auger electron spectroscopy analysis of SiC-whisker surfaces and SiC-whisker/alumina interfaces". Journal of Materials Research 10, nr 4 (kwiecień 1995): 1016–23. http://dx.doi.org/10.1557/jmr.1995.1016.
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Auger Electron Spectroscopy (AES) has been used to examine as-received and oxidized silicon carbide whiskers and their respective whisker/matrix interfaces after fabrication into SiC-whisker-reinforced alumina composites. As-received whisker surfaces exhibited a 2–3 nm-thick near-surface region that was C-rich. Oxygen was detected at the outer surface, but diminished to near zero within 25 nm of the surface. Oxidized whiskers had 60 nm-thick SiO2 surface layers, which was in agreement with the transmission electron microscopy observations. The whisker/matrix interfaces in both composites consisted of thin (<0.5 nm) layers of a C-Si-O noncrystalline material. The thick SiO2 layers on the oxidized whiskers were ejected from the interfaces during hot-pressing. It was concluded that (i) the higher toughness of the composite fabricated with as-received SiC whiskers may be related to the higher C and lower O in its SiCw/Al2O3 interfaces, and (ii) interface composition cannot be reliably predicted using the surface composition of free whiskers prior to fabrication.
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RAMAN, KARTHIK V., NICOLAE ATODIRESEI i JAGADEESH S. MOODERA. "TAILORING FERROMAGNET–MOLECULE INTERFACES: TOWARDS MOLECULAR SPINTRONICS". SPIN 04, nr 02 (czerwiec 2014): 1440014. http://dx.doi.org/10.1142/s2010324714400141.
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Understanding the interaction of organic molecules adsorbed on magnetic surfaces has shown considerable progress in recent years. The creation of hybridized interface between carbon-based aromatic molecule and the magnetic surface is observed to give rise to new interface states with unique electronic and magnetic character. This study has opened up a molecular-design initiative to tailor the spin dependent electronic and magnetic functionalities of the hybrid interface. The purpose of this article is to provide a fundamental understanding of the spin-chemistry and spin-physics associated with the formation of such ferromagnet-molecule hybrid interfaces. We also discuss the recent progress in this field using state-of-the-art experiments and theoretical calculations with focus on the magnetic properties of the molecule and the magnetic surface. The study reveals several interesting interface phenomena: formation of induced molecular moment and exchange coupling with the magnetic surface, and molecular spin-filters. It also demonstrates significant changes in the magnetic anisotropy and inter-atomic magnetic exchange coupling of the magnetic surface. These studies open the possibilities of exploring new molecular functionalities toward further research in the subfield of interface-assisted molecular spintronics.
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Koberstein, Jeffrey T. "Surface and Interface Modification of Polymers". MRS Bulletin 21, nr 1 (styczeń 1996): 19–23. http://dx.doi.org/10.1557/s0883769400035090.
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The properties of polymeric surfaces and interfaces are ubiquitous in their myriad commercial applications: paints and coatings, adhesives, lubrication, biocompatible materials, flocculation and steric stabilization of colloids, membranes and separation media, immiscible polymer blends, and filled composites. Some of these applications require low-energy surfaces that are chemically inert and are not easily wet with other materials. Other applications require high adhesion and strong interactions between the polymer and substrate. This article discusses fundamental principles governing the behavior of polymer surfaces and interfaces, then illustrates various means available for polymer-interface modification.
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Elfring, Gwynn J., L. Gary Leal i Todd M. Squires. "Surface viscosity and Marangoni stresses at surfactant laden interfaces". Journal of Fluid Mechanics 792 (4.03.2016): 712–39. http://dx.doi.org/10.1017/jfm.2016.96.
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We calculate here the force on a probe at a viscous, compressible interface, laden with soluble surfactant that equilibrates on a finite time scale. The motion of the probe through the interface drives variations in the surfactant concentration at the interface that in turn leads to a Marangoni flow that contributes to the force on the probe. We demonstrate that the Marangoni force on the probe depends non-trivially on the surface shear and dilatational viscosities of the interface indicating the difficulty in extracting these material properties from force measurements at compressible interfaces.
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Li, Yifan, Yunlu Pan i Xuezeng Zhao. "Interface conditions of roughness-induced superoleophilic and superoleophobic surfaces immersed in hexadecane and ethylene glycol". Beilstein Journal of Nanotechnology 8 (27.11.2017): 2504–14. http://dx.doi.org/10.3762/bjnano.8.250.
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Interface conditions are an important property that can affect the drag of fluid flow. For surfaces with different oleophobicity, the boundary slip at the solid–oil interface is mostly larger than that at the solid–water interface. Roughness is a key factor for the wettability of superoleophilic/superoleophobic surfaces, and it has been found to affect the effective value of slip length in measurements. Moreover, there are no studies on the effect of roughness on slip at interfaces between oil and superoleophilic/superoleophobic surfaces. A theoretical description of the real surface roughness is yet to be found. Results show that the effective slip length is negative and decreases with an increasing root mean squared (RMS) roughness of surfaces, as the increasing roughness enhances the area with discontinuous slip at the solid–liquid interface. The underlying mechanisms are analyzed. The amplitude parameters of surface roughness could significantly inhibit the degree of boundary slip on both superoleophilic surfaces in Wenzel state and superoleophobic surfaces in Cassie state immersed in oil. The oleic systems were likely to enhance boundary slip and resulted in a corresponding reduction in drag with decreasing roughness on the solid–oil interfaces.
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Khanna, Shaweta, Arti Noor, Man Singh Tyagi i Sonnathi Neeleshwar. "Interface States and Barrier Heights on Metal/4H-SiC Interfaces". Materials Science Forum 615-617 (marzec 2009): 427–30. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.427.
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Available data on Schottky barrier heights on silicon and carbon rich faces of 4H-SiC have been carefully analyzed to investigate the mechanism of barrier formation on these surfaces. As in case of 3C and 6H-SiC, the barrier heights depend strongly upon method of surface preparation with a considerable scatter in the barrier height for a given metal-semiconductor system. However, for each metal the barrier height depends on the metal work function and strong pinning of the Fermi level has not been observed. The slopes of the linear relation between the barrier heights and metal work functions varies over a wide range from 0.2 to about 0.75 indicating that the density of interface states depends strongly on the method of surface preparation. By a careful examination of the data on barrier heights we could identify a set of nearly ideal interfaces in which the barrier heights vary linearly with metal work function approaching almost to the Schottky limit. The density of interface states for these interfaces is estimated to lie between 4.671012 to 2.631012 states/ cm2 eV on the silicon rich surface and about three times higher on the carbon rich faces. We also observed that on these ideal interfaces the density of interface states was almost independent of metal indicating that the metal induced gap states (MIGS) play no role in determining the barrier heights in metal-4H-SiC Schottky barriers.
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Leistner, Tom, Michael Türk, Alfred Weber, Christian Weber i Urs A. Peuker. "Selective Separation Using Fluid-Liquid Interfaces". Materials Science Forum 959 (czerwiec 2019): 113–24. http://dx.doi.org/10.4028/www.scientific.net/msf.959.113.
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Interfaces between two fluid phases are a potential barrier for particles. Certain particles may not be able to pass such an interface, because they have to overcome a certain resistance. The latter depends on the strength of the interface, which is the surface tension. The second relevant property is the three phase wetting angle, which shows the fluid with the preferred wetting to the particle surface. It depends on the particle properties, like chemical composition, surface structure and surface modification. The third relevant parameter is the particle size. From these three main influence parameters it emerges that fluid-fluid interfaces can show a selectivity to special particle properties, which enables a separation of a particle mixture. Since there are possibilities to address the governing effects, the separation cut, size or composition cut respectively, can be engineered in a certain range. Separation at boundaries is feasible when the driving force is in the same order of magnitude as the retaining resistance force of the interface. The driving force is either the Brownian movement for very small particles or any field force like gravity or the centrifugal force. To describe the separation at interfaces it is necessary to understand the process of the phase transfer of particles through the interface, either the gas-liquid or the liquid-liquid interface between two immiscible liquids. In addition to the effects mentioned above, also dynamic phenomena such as surfactant depletion of the interface may have to be taken into account.
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Porojan, Liliana, Mihaela Bîrdeanu, Cristina Savencu i Sorin Porojan. "Characterization of Dental Metal-Ceramic Interfaces of Heat Pressed Ceramics on Co-Cr Frameworks Obtained with Different Technologies". Applied Mechanics and Materials 876 (luty 2018): 25–30. http://dx.doi.org/10.4028/www.scientific.net/amm.876.25.
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It is known that the quality of metal-ceramic restorations mainly depends on the interface strength. The aim of the study was to evaluate metal–ceramic interfaces of heat pressed ceramic on Co-Cr frameworks obtained with different technologies: melting-casting (CST), computerized milling (MIL), selective laser sintering (SLS) and selective laser melting (SLM). The microstructure of metal–ceramic interfaces and framework topography were characterized by scanning electron microscope (SEM). Sandblasted, polished surfaces and the cross section on the interfaces were observed. Sandblasted surfaces presented a uniform rough aspect and pronounced porous surface compared to that of polished surfaces and were better visible in SLS and SLM samples. The thickness of the veneer layer had a noticeable effect on the interface, because in the case of thicker veneers, cracks at the interfaces were visible for CST and MIL specimens. Considering the findings reported herein, some suggestions can be considered in practice, such as adaptation of the restorations morphology to the characteristics of the processed materials.
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Saleman, Abdul Rafeq, Mohamad Shukri Zakaria, Ridhwan Jumaidin, Nur Hazwani Mokhtar i Nor Aslily Sarkam. "Molecular Dynamics Study: Correlation of Heat Conduction Across S-L Interfaces Between Constant Heat Flux and Shear Applied to Liquid Systems". Journal of Mechanical Engineering 19, nr 3 (15.09.2022): 33–53. http://dx.doi.org/10.24191/jmeche.v19i3.19795.
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Heat conduction (HC) at solid-liquid (S-L) interfaces play a significant role in the performance of engineering systems. Thus, this study investigates HC at S-L interfaces and its correlation between constant heat flux (CHF) and shear applied to liquid (SAL) systems using non-equilibrium molecular dynamics simulation. The S-L interface consists of solids with the face-centred cubic (FCC) lattice of (110), (111) and (100) planes facing the liquid. The solid is modelled by Morse potential whereas the liquid is modelled by Lennard Jones potential. The interaction between solid-liquid was modelled by Lorentz-Bertholet combining rules. The temperature and heat flux of the system is evaluated to correlate the HC at the S-L interface which reflect by the interfacial thermal resistance (ITR). The results suggest that the surfaces of FCC influence ITR at the S-L interface. The (110) surface for both cases of CHF and SAL has the lowest ITR as compared to other surfaces. In general, ITR for the case of SAL is higher than the CHF. SAL disturbs the adsorption behaviour of liquid at the S-L interfaces, thus reducing the HC. In conclusion, the surface of FCC and liquid experiencing shear do influence the characteristics of HC at the S-L interface.
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Pascall, Andrew J., i Todd M. Squires. "Electrokinetics at liquid/liquid interfaces". Journal of Fluid Mechanics 684 (28.09.2011): 163–91. http://dx.doi.org/10.1017/jfm.2011.288.
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AbstractElectrokinetic effects at liquid/liquid interfaces have received considerably less attention than at solid/liquid interfaces. Because liquid/liquid interfaces are generally mobile, one might expect electrokinetic effects over a liquid/liquid interface to be faster than over an equivalent solid surface. The earliest predictions for the electrophoretic mobility of charged mercury drops – distinct approaches by Frumkin, along with Levich, and Booth – differed by $O(a/ {\lambda }_{D} )$, where $a$ is the radius of the drop and ${\lambda }_{D} $ is the Debye length. Seeking to reconcile this rather striking discrepancy, Levine & O’Brien showed double-layer polarization to be the key ingredient. Without a physical mechanism by which electrokinetic effects are enhanced, however, it is difficult to know how general the enhancement is – whether it holds only for liquid metal surfaces, or more generally, for all liquid/liquid surfaces. By considering a series of systems in which a planar metal strip is coated with either a liquid metal or liquid dielectric, we show that the central physical mechanism behind the enhancement predicted by Frumkin is the presence of an unmatched electrical stress upon the electrolyte/liquid interface, which establishes a Marangoni stress on the droplet surface and drives it into motion. The source of the unbalanced electrokinetic stress on a liquid metal surface is clear – metals represent equipotential surfaces, so no field exists to drive an equal and opposite force on the surface charge. This might suggest that liquid metals represent a unique system, since dielectric liquids can support finite electric fields, which might be expected to exert an electrical stress on the surface charge that balances the electric stress. We demonstrate, however, that electrical and osmotic stresses on relaxed double layers internal to dielectric liquids precisely cancel, so that internal electrokinetic stresses generally vanish in closed, ideally polarizable liquids. The enhancement predicted by Frumkin for liquid mercury drops can thus be expected quite generally over ideally polarizable liquid drops. We then reconsider the electrophoretic mobility of spherical drops, and reconcile the approaches of Frumkin and Booth: Booth’s neglect of double-layer polarization leads to a standard electro-osmotic flow, without the enhancement, and Frumkin’s neglect of the detailed double-layer dynamics leads to the enhanced electrocapillary motion, but does not capture the (sub-dominant) electrophoretic motion. Finally, we show that, while the electrokinetic flow over electrodes coated with thin liquid films is $O(d/ {\lambda }_{D} )$ faster than over solid/liquid interfaces, the Dukhin number, $\mathit{Du}$, which reflects the importance of surface conduction to bulk conduction, generally increases by a smaller amount [$O(d/ L)$], where $d$ is the thickness of film and $L$ is the length of the electrode. This suggests that liquid/liquid interfaces may be utilized to enhance electrokinetic velocities in microfluidic devices, while delaying the onset of high-$\mathit{Du}$ electrokinetic suppression.
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BACHRACH, R. Z., R. D. BRINGANS, MARJORIE A. OLMSTEAD i R. I. G. UHRBERG. "SYNCHROTRON RADIATION STUDIES OF MBE FORMED SEMICONDUCTOR INTERFACES: Si-GaAs AND GaAs-Si". Modern Physics Letters B 01, nr 03 (czerwiec 1987): 97–109. http://dx.doi.org/10.1142/s0217984987000144.
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Studies of silicon on gallium arsenide and gallium arsenide on silicon interface formation will be described and used as examples of how synchrotron radiation excited photoemission is a powerful probe of surface and interface phenomena. The samples and interfaces studied in this work were prepared in-situ using thermal Ga and As MBE sources and a resistive Si evaporation source. The MBE capability has allowed us to explore atomic and electronic structural issues of interface formation during hetero-epitaxy. We have combined these techniques to explore Si and GaAs surfaces, the adsorbate interactions of Ga and As on Si, and interface formation of Si on GaAs and the inverse system, GaAs on Si. Several of these surfaces and interfaces yield model systems which can provide general insights. As an example, studies of arsenic terminated silicon (100) and (111) surfaces will be described. A specific focus of the paper will be the interfacial development of Si on GaAs(100). Si deposited at various coverages below 10 ml onto a room temperature substrate yields a disordered surface. For coverages below two monolayers, subsequent annealing at 450–600°C leads to a single domain 1×2 surface from either the As rich c(2×8) or Ga rich 4×6 reconstructions. While the periodicity is the same for the different starting surfaces, evidence is presented that the atomic arrangement in the unit cell is different.
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Styler, S. A., M. E. Loiseaux i D. J. Donaldson. "Substrate effects in the photoenhanced ozonation of pyrene". Atmospheric Chemistry and Physics Discussions 10, nr 11 (15.11.2010): 27825–52. http://dx.doi.org/10.5194/acpd-10-27825-2010.
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Abstract. We report the effects of actinic illumination on the heterogeneous ozonation kinetics of solid pyrene films and pyrene adsorbed at air-octanol and air-aqueous interfaces. Upon illumination, the ozonation of solid pyrene films and pyrene at the air-aqueous interface proceeds more quickly than in darkness; no such enhancement is observed for pyrene at the air-octanol interface. Under dark conditions, the reaction of pyrene at all three interfaces proceeds via a Langmuir-Hinshelwood-type surface mechanism. In the presence of light, Langmuir-Hinshelwood kinetics are observed for solid pyrene films but a linear dependence upon gas-phase ozone concentration is observed at the air-aqueous interface. We interpret these results as evidence of the importance of charge-transfer pathways for the ozonation of excited-state pyrene. The dramatically different behaviour of pyrene at the surface of these three simple reaction environments highlights the difficulties inherent in representing complex reactive surfaces in the laboratory, and suggests caution in extrapolating laboratory results to environmental surfaces.
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Styler, S. A., M. E. Loiseaux i D. J. Donaldson. "Substrate effects in the photoenhanced ozonation of pyrene". Atmospheric Chemistry and Physics 11, nr 3 (14.02.2011): 1243–53. http://dx.doi.org/10.5194/acp-11-1243-2011.
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Abstract. We report the effects of actinic illumination on the heterogeneous ozonation kinetics of solid pyrene films and pyrene adsorbed at air-octanol and air-aqueous interfaces. Upon illumination, the ozonation of solid pyrene films and pyrene at the air-aqueous interface proceeds more quickly than in darkness; no such enhancement is observed for pyrene at the air-octanol interface. Under dark conditions, the reaction of pyrene at all three interfaces proceeds via a Langmuir-Hinshelwood-type surface mechanism. In the presence of light, Langmuir-Hinshelwood kinetics are observed for solid pyrene films but a linear dependence upon gas-phase ozone concentration is observed at the air-aqueous interface. We interpret these results as evidence of the importance of charge-transfer pathways for the ozonation of excited-state pyrene. The dramatically different behaviour of pyrene at the surface of these three simple reaction environments highlights the difficulties inherent in representing complex reactive surfaces in the laboratory, and suggests caution in extrapolating laboratory results to environmental surfaces.
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Hicks, J., R. Ellis, C. Flaitz, G. Westerman i L. Powell. "Restoration-enamel interface with argon laser and visible light polymerization of compomer and composite resin restorations: a polarized light and scanning electron microscopic in vitro study". Journal of Clinical Pediatric Dentistry 27, nr 4 (1.07.2003): 353–58. http://dx.doi.org/10.17796/jcpd.27.4.dj286712r2r85345.
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This polarized light (PL) and scanning electron microscopic (SEM) in vitro study investigated the effect of argon laser (AL) and visible light (VL) polymerization on the interfaces between compomer and composite resin restorations and the enamel cavosurfaces. Surface topography by SEM revealed a smooth transition between the restorative materials and adjacent enamel surfaces with no microspaces between the restorations and enamel surfaces. The enamel surfaces showed relatively smooth surface coatings with AL curing, compared with exposure of etched prism endings with VL curing. The restoration-enamel interface by PL showed an intimate relationship between the restorative materials and the cavosurface enamel. No differences were found between AL and VL polymerization.With the restoration-enamel interface by SEM, compomers and composite resins were adapted closely to the cavosurface enamel and tags of restorative material protruded into the adjacent cavosurface enamel. Both VL and AL polymerization of compomers and composite resin restorations in vitro produced closely adapted restorations with intimate restorationenamel interfaces. Such restoration-enamel interfaces may provide a certain degree of resistance against secondary caries formation, and this may be enhanced by the caries protective effect of argon laser irradiation.
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Josell, Daniel, i Frans Spaepen. "Surfaces, Interfaces, and Changing Shapes in Multilayered Films". MRS Bulletin 24, nr 2 (luty 1999): 39–43. http://dx.doi.org/10.1557/s0883769400051538.
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It is generally recognized that the capillary forces associated with internal and external interfaces affect both the shapes of liquid-vapor surfaces and wetting of a solid by a liquid. It is less commonly understood that the same phenomenology often applies equally well to solid-solid or solid-vapor interfaces.The fundamental quantity governing capillary phenomena is the excess free energy associated with a unit area of interface. The microscopic origin of this excess free energy is often intuitively simple to understand: the atoms at a free surface have “missing bonds”; a grain boundary contains “holes” and hence does not have the optimal electronic density; an incoherent interface contains dislocations that cost strain energy; and the ordering of a liquid near a solid-liquid interface causes a lowering of the entropy and hence an increase in the free energy. In what follows we shall show how this fundamental quantity determines the shape of increasingly complex bodies: spheres, wires, thin films, and multilayers composed of liquids or solids. Crystal anisotropy is not considered here; all interfaces and surfaces are assumed isotropic.Consideration of the equilibrium of a spherical drop of radius R with surface free energy γ shows that pressure inside the droplet is higher than outside. The difference is given by the well-known Laplace equation:This result can be obtained by equating work done against internal and external pressure during an infinitesimal change of radius with the work of creating a new surface.
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Huang, Jingtao, Jingteng Xue, Mingwei Li, Yuan Cheng, Zhonghong Lai, Jin Hu, Fei Zhou, Nan Qu, Yong Liu i Jingchuan Zhu. "First-Principles Computation of Microscopic Mechanical Properties and Atomic Migration Behavior for Al4Si Aluminum Alloy". Metals 13, nr 9 (20.09.2023): 1622. http://dx.doi.org/10.3390/met13091622.
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In this paper, the interfacial behavior and the atom diffusion behavior of an Al4Si alloy were systematically investigated by means of first-principles calculations. The K-points and cutoff energy of the computational system were determined by convergence tests, and the surface energies for five different surfaces of Al4Si alloys were investigated. Among the five surfaces investigated for Al4Si, it was found that the (111) surface was the surface with the lowest surface energy. Subsequently, we investigated the interfacial stability of the (111) surface and found that there were two types of interfaces, the Al/Al interface and the Al/Si interface. The fracture energies and theoretical strengths of the two interfaces were calculated; the results show that the Al/Al interface had the highest interfacial strength, and the calculation of their electronic results explained the above phenomenon. Subsequently, we investigated the diffusion and migration behavior of Si atoms in the alloy system, mainly in the form of vacancies. We considered the diffusion of Si atoms in vacancies of Al and Si atoms, respectively; the results showed that Si atoms are more susceptible to diffusive migration to Al atomic vacancies than to Si atomic vacancies. The results of the calculations on the micromechanics of aluminum alloys, as well as the diffusion migration behavior, provide a theoretical basis for the further development of new aluminum alloys.
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PRIVMAN, VLADIMIR. "FLUCTUATING INTERFACES, SURFACE TENSION, AND CAPILLARY WAVES: AN INTRODUCTION". International Journal of Modern Physics C 03, nr 05 (październik 1992): 857–77. http://dx.doi.org/10.1142/s0129183192000531.
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We present an introduction to modern theories of interfacial fluctuations and the associated interfacial parameters: surface tension and surface stiffness, as well as their interpretation within the capillary wave model. Transfer matrix spectrum properties due to fluctuation of an interface in a long-cylinder geometry are reviewed. The roughening transition and properties of rigid interfaces below the roughening temperature in 3d lattice models are surveyed with emphasis on differences in fluctuations and transfer matrix spectral properties of rigid vs. rough interfaces.
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Savotchenko, S. E. "Nonlinear surface waves propagating along the composite waveguide consisting of self-focusing slab between defocusing media separated by interfaces with nonlinear response". Journal of Nonlinear Optical Physics & Materials 28, nr 04 (grudzień 2019): 1950039. http://dx.doi.org/10.1142/s0218863519500395.
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The model of the composite symmetric waveguide consisting of self-focusing slab between defocusing nonlinear media separated by interfaces characterized by own nonlinearity response is proposed. Two new types of nonlinear surface waves propagating along it with anti-phase amplitude oscillations at interface planes are found. The frequencies of the nonlinear surface waves existing near the interfaces with the nonlinear response only are calculated analytically. The conditions of the surface wave existence are found. The frequencies and localization distances of the surface waves in dependence on nonlinearity waveguide parameters, slab width and interface characteristics are analyzed.
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CHEN, KUNFENG, FEI LIU, XITONG LIANG i DONGFENG XUE. "SURFACE–INTERFACE REACTION OF SUPERCAPACITOR ELECTRODE MATERIALS". Surface Review and Letters 24, nr 03 (30.03.2017): 1730005. http://dx.doi.org/10.1142/s0218625x17300052.
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Facing the challenge of low energy density of conventional electric double layer supercapacitors, researchers have long been focusing on the development of novel pseudocapacitive electrode materials with higher energy densities. Since capacitive charge storage reaction mostly occurs on the interface of electrode and electrolyte, the interface chemistry determines the achievable power and energy densities of a supercapacitor. Consequently, understanding of surface–interface reaction mechanism is a key towards efficient design of high-performance supercapacitor electrode materials. In this paper, we have reviewed the recent advances in the understanding of surfaces–interfaces in the system of pseudocapacitive supercapacitors. With significant research advancements in the understanding of surface–interface of supercapacitors, novel colloidal electrode materials with improved surface–interface structures have been developed in our previous work, which have the potential to deliver both high energy and power densities. This review aims to provide an in-depth analysis on the surface–interface control approaches to improve the energy and power densities of supercapacitors.
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Kanev, Kamen. "Tangible Interfaces for Interactive Multimedia Presentations". Mobile Information Systems 4, nr 3 (2008): 183–93. http://dx.doi.org/10.1155/2008/982947.
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This article is devoted to tangible interfaces for steering and control of interactive multimedia presentations. Various methods for digital encoding of physical objects are considered and their applicability in surface encoding for tangible interface components is discussed. Experiments with presentation controls, based on direct interaction with digitally encoded printed handouts are reported. An innovative approach for transferring presentation controls from printed handouts to surfaces of real physical objects is introduced. Consequently labels, digitally enhanced with CLUSPI codes are created and presentation control trials involving real products with digitally encoded surfaces are conducted. USB and wireless cameras are employed as CLUSPI readers for implementing surface based interactions and a portable communication device with an embedded camera is considered as a possible truly mobile solution.
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HASEGAWA, SHUJI, i SHOZO INO. "CORRELATION BETWEEN ATOMIC-SCALE STRUCTURES AND MACROSCOPIC ELECTRICAL PROPERTIES OF METAL-COVERED Si(111) SURFACES". International Journal of Modern Physics B 07, nr 22 (10.10.1993): 3817–76. http://dx.doi.org/10.1142/s0217979293003504.
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In this review, we discuss the relation between the atomic-scale structures (atomic arrangements and electronic states) and the macroscopic electrical properties (surface conductance and Schottky barriers) of metal(Ag, Au, or In)-covered Si (111) surfaces. These surfaces have been one of the most intensively investigated systems with the use of a variety of modern surface science techniques, and diversified information at atomic scales has been obtained. The data of reflection high-energy electron diffraction, scanning tunneling microscopy/spectroscopy, photoemission spectroscopies, and others are utilized here for characterizing the structures. Surface conductance and Schottky barriers, on the other hand, have also been the major areas in semiconductor physics for, especially device-oriented, research, but these have rarely been studied in combination with atomic-scale structures. These electrical properties have recently been found to be crucially dependent on the local atomic structures of well-defined surfaces/interfaces. The atomic arrangements and the resulting surface/interface electronic states govern the Fermi-level pinning and band bending which determine the electrical properties of semiconductor surfaces/interfaces.
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Jones, Jessica Catharine, Ethan Kamphaus, Jeffrey R. Guest, Lei Cheng i Alex B. F. Martinson. "Targeted Dehydration As a Route to Site-Selective Atomic Layer Deposition at TiO2 Defects". ECS Meeting Abstracts MA2022-02, nr 31 (9.10.2022): 1131. http://dx.doi.org/10.1149/ma2022-02311131mtgabs.
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Crystallographic perfection in epitaxial thin film heterostructures can eliminate interface defects that dilute unique properties and reduce device performance. However, the requirement for epitaxial perfection greatly limits the selection of material candidates and deposition processes. Using selective interface reactions (SIRs), an atomic layer deposition (ALD)-based technique, we target transformation of undesirable defect sites at imperfect surfaces. Defects on the TiO2 surface affect the electronic properties, interfaces, and performance of optoelectronic devices that leverage TiO2 interfaces. We present first principles calculations to predict the difference in hydration/hydroxylation of pristine TiO2 terraces and minority atomic configurations (i.e. “defects”) including step edges and oxygen vacancies. We investigate hydroxylation differences through temperature dependent scanning tunneling microscopy (STM), and ultimately exploit these differences to selectively react ALD precursors at surface defect sites.
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KÄRKKÄINEN, LEO, i KARI RUMMUKAINEN. "CRITICAL SURFACE EXPONENTS IN 2-D 10-STATE POTTS MODEL". International Journal of Modern Physics C 03, nr 05 (październik 1992): 1125–36. http://dx.doi.org/10.1142/s0129183192000750.
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At low temperature, the Potts models can have interfaces between domains ordered to different directions. We use the difference of periodic and twisted boundary conditions to study planar order-order interfaces. We show that the interface tension, energy and width display critical properties as one approaches the critical point. We measure the critical exponents connected to their power like singular behaviour at the critical point.
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FAETTI, SANDRO, i EPIFANIO G. VIRGA. "On nematic surface energies". European Journal of Applied Mathematics 8, nr 3 (czerwiec 1997): 293–99. http://dx.doi.org/10.1017/s0956792597003136.
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We review the main outcomes of a continuum theory for the equilibrium of the interface between a nematic liquid crystal and an isotropic environment, in which the surface free energy density bears terms linear in the principal curvatures of the interface. Such geometric contributions to the energy occur together with more conventional elastic contribution, leading to an effective azimuthal anchoring of the optic axis, which breaks the isotropic symmetry of the interface. The theory assumes the interface to be fixed, as for a rigid cavity filled with liquid crystal, and so it does not apply to drops. It should be appropriate when the curvatures of the interface are small compared to that of the molecular interaction sphere. Also, interfaces bearing a sharp edge are encompassed within the theory; a line integral expresses the energy condensed along the edge: we see how it affects the equilibrium equations.
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FUKUI, Ken-ichi. "Surface Analyses for Better Understanding of Surfaces and Interfaces". Hyomen Kagaku 34, nr 11 (2013): 567. http://dx.doi.org/10.1380/jsssj.34.567.
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Kis-Varga, Miklos, G. A. Langer, A. Csik, Z. Erdélyi i Dezső L. Beke. "Effect of Substrate Temperature on the Different Diffuseness of Subsequent Interfaces in Binary Multilayers". Defect and Diffusion Forum 277 (kwiecień 2008): 27–31. http://dx.doi.org/10.4028/www.scientific.net/ddf.277.27.
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Epitaxial, coherent Mo/V multilayers were deposited by magnetron sputtering on (001) oriented MgO substrates at 873K (sample MoV-T), 923K (sample MoV-U) and 973K (sample MoV-V), respectively. In order to estimate the concentration profiles in our multilayers, a superlattice refinement modelling procedure has been used on high-angle XRD symmetric scans. The Mo/V interfaces were always sharper than V/Mo ones (in this notation the order of element reflects the sequence of deposition: e.g. the Mo/V interface was formed by the deposition of the V on the Mo surface). Furthermore the interface diffuseness was only slightly different at the lowest substrate temperature, but the difference increased with increasing temperature and an abrupt concentration jump could be observed at the Mo/V interface in the sample, sputtered at the 973 K. This indicates that during deposition the interfacial mixing by impact exchange events is important and thermally activated processes (surface diffusion and/or jumps driven by segregation) are less effective. With increasing substrate temperature the thickness of the V/Mo interfaces were unchanged while the Mo/V interface became shaper and sharper i.e. thermally activated jumps were more active during deposition of V atoms. Thus in forming Mo/V interfaces the segregation tendency of V to the Mo surface results in enhanced exchanges between V atoms (buried in the near surface layers of the Mo substrate) and surface Mo atoms, leading to more sharper interface with increasing temperature. On the other hand during the formation of the V/Mo interfaces the chemical thickness of the interface, provided again by impact exchanges, was practically unchanged.
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Alexandris, Stelios, Daniel Ashkenazi, Jan Vermant, Dimitris Vlassopoulos i Moshe Gottlieb. "Interfacial shear rheology of glassy polymers at liquid interfaces". Journal of Rheology 67, nr 5 (21.08.2023): 1047–60. http://dx.doi.org/10.1122/8.0000685.
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When surface-active molecules or particles assemble at fluid–fluid interfaces, these interfaces acquire complex rheological properties that are of importance in processes that involve flow and deformation of interfaces. Although much progress has been made, interfacial rheology measurements and, in particular, the measurement of interfacial rheological properties of polymers at the air-water interface remain challenging. These are due to weak interactions with the water subphase, the polymer backbone conformation, the glass transition of the interfacial layer, and memory effects. In the present work, we describe systematic rheological measurements of polymer-laden interfaces. The measurements were performed with four different interfacial shear rheometers that can be classified into two types: rheometers in which the surface pressure can be controlled independently, and devices based on fixtures mounted on standard rotational rheometers and lacking control of the surface pressure. We use poly(tert-butyl methacrylate) and poly(methyl methacrylate), two high glass transition temperature, hydrophobic polymers anchored to the water subphase by means of the acrylate group. Using a Langmuir–Pockels (LP) trough, we identify the transition of the polymer monolayer from a viscous to a solid elastic or soft-glassy interface as the polymer surface concentration increases by compression. Then, we compare the linear viscoelastic properties of the interface as obtained by each rheometer. Our results show poor reproducibility and comparability of the rheological data as obtained by different rheometers for the same polymer. This is mainly due to differences in the method used to prepare the layers. For LP-based devices, spreading under dilute conditions and subsequent compression yields layers of compressed glassy blobs with reproducible results. On the other hand, for devices without surface pressure control, deposition of the amount needed to reach a desired concentration may lead to the formation of ill-defined layers resulting in irreproducible data. Furthermore, we find that only when spreading the polymer to form a dilute layer and then controlling the surface pressure by compression, we can clearly distinguish the fluidlike from solidlike interfaces, and a clear correlation is observed between the surface pressure (or interfacial polymer concentration) and the rheological properties of the interface.
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Jiang, Guojun, i Sheng Xie. "Comparison of AFM Nanoindentation and Gold Nanoparticle Embedding Techniques for Measuring the Properties of Polymer Thin Films". Polymers 11, nr 4 (3.04.2019): 617. http://dx.doi.org/10.3390/polym11040617.
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The surfaces of polymer and interfaces between polymer and inorganic particles are of particular importance for the properties of polymers and composites. However, the determination of the properties of surfaces and interfaces poses many challenges due to their extremely small dimensions. Herein, polystyrene and polymethyl methacrylate thin film on silicon wafer was used as a model system for the measurement of the properties of the polymer near free surface and at the polymer-solid interface. Two different methods, i.e., nanoindentation using atomic force microscopy (AFM) and the gold nanoparticle embedding technique, were used for these measurements. The results showed the elastic modulus of PS near the free surface determined by nanoindentation was lower than the bulk value. Based on contact mechanics analysis, nanoparticle embedding also revealed the existence of a lower-modulus, non-glassy layer near the free surface at temperatures below the bulk glass transition temperature (Tg). However, near the polymer-solid interface, the AFM nanoindentation method is not applicable due to the geometry confinement effect. On the other hand, the nanoparticle embedding technique can still correctly reflect the interactions between the polymer and the substrate when compared to the ellipsometry results.
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Yakovkin, I. N. "Surface and Interface Bands of the CdTe–HgTe–CdTe Heterostructure: Evidence of Metallicity". Ukrainian Journal of Physics 66, nr 7 (4.08.2021): 630. http://dx.doi.org/10.15407/ujpe66.7.630.
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Performed full-relativistic DFT calculations have demonstrated that thin HgTe layers are metallic and, with increasing thickness, do not become insulators – either ordinary band insulators or topological insulators. The variations of the potential at the CdTe–HgTe interfaces are found to be negligible in comparison with those at the terminating surfaces of the CdTe–HgTe–CdTe films, so that the interfaces in fact do not form any potential well. It is shown that the interface-related bands of the CdTe–HgTe–CdTe films are situated well below EF, so that a dominant input into the density of states at EF and, therefore, to the conductivity is provided not by the interface states, but by the surface bands of the net layered system. It is reasonable therefore to consider an alternative interpretation of the reported thickness dependence of the conductivity of the system, such as the possible surface segregation of components or unavoidable contaminations, which seems much more realistic than the interpretation based on involving topological insulators and topologically protected surface states.
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HASEGAWA, HIDEKI. "MICROSCOPIC UNDERSTANDING AND CONTROL OF SURFACES AND INTERFACES OF COMPOUND SEMICONDUCTORS FOR MESOSCOPIC DEVICES". Surface Review and Letters 07, nr 05n06 (październik 2000): 583–88. http://dx.doi.org/10.1142/s0218625x0000066x.
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Microscopic properties of free surfaces and metal–semiconductor interfaces related to successful realization of mesoscopic devices are discussed for III–V compound semiconductors, with a particular emphasis on Fermi level pinning. Surface states causing pinning are present even on freshly MBE-grown clean (001) and (110) surfaces with well-defined surface structures. Scanning tunneling spectroscopy (STS) measurement gives anomalous spectra with large conductance gaps, and this can be explained by tip-induced local charging of surface states. Pinning on free surfaces can be considerably suppressed by a surface passivation using an ultrathin MBE-grown silicon interface control layer (Si ICL). In mesoscopic scale metal–semiconductor contacts, Fermi level pinning underneath the metal contact itself is remarkably reduced with the use of the optimum in situ electrochemical metal deposition. However, Fermi level pinning on the surrounding free surfaces has large effects on current transport and capacitance properties in such contacts.
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FLORES, FERNANDO, JOSÉ ORTEGA i RUBÉN PÉREZ. "MANY-BODY EFFECTS AND THE METAL–INSULATOR TRANSITION AT SEMICONDUCTOR SURFACES AND INTERFACES". Surface Review and Letters 06, nr 03n04 (czerwiec 1999): 411–33. http://dx.doi.org/10.1142/s0218625x99000421.
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The aim of this paper is to present a general perspective of the different correlation effects appearing at semiconductor surfaces and interfaces. The unifying theoretical picture is the generalized Hubbard Hamiltonian. In a first step, we show how such Hamiltonians can be analyzed using both a local density approach and many-body techniques. This discussion shows how to determine the different electron–electron interaction parameters appearing in the generalized Hubbard Hamiltonian, from a set of restricted LDA calculations for the full surface. Then, different surfaces and interfaces are analyzed; in particular, we consider the Si(111)-(7 × 7), -(5 × 5) and -(3 × 3) reconstructions as well as the Si-rich SiC(111)-[Formula: see text] and -(3 × 3) surfaces. These Si-rich SiC(111) surfaces are shown to behave like a Mott–Hubbard insulator, while the Si(111) reconstructions are charge transfer systems presenting a variety of different behaviors; thus, the Si(111)-(7 × 7) is metallic, while the -(5 × 5) and the -(3 × 3) are found to be insulating. We have also analyzed the Sn/Ge(111)-(3 × 3) reconstruction, the alkali metal/GaAs(110) junction and the K/Si(111)-[Formula: see text]-B interface. Our discussion shows that the alkali metal/GaAs and K/Si(111) interfaces present also a Mott–Hubbard metal–insulator transition, and that the Sn/Ge(111)-(3 × 3) interface is still metallic in spite of nonnegligible many-body effects appearing in the surface band density of states. We conclude that two-dimensional systems at semiconductor surfaces and interfaces present a rich variety of many-body effects that modify substantially the one-electron picture one gets from LDA calculations.
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Heinz, Hendrik, Kshitij C. Jha, Jutta Luettmer-Strathmann, Barry L. Farmer i Rajesh R. Naik. "Polarization at metal–biomolecular interfaces in solution". Journal of The Royal Society Interface 8, nr 55 (14.07.2010): 220–32. http://dx.doi.org/10.1098/rsif.2010.0318.
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Metal surfaces in contact with water, surfactants and biopolymers experience attractive polarization owing to induced charges. This fundamental physical interaction complements stronger epitaxial and covalent surface interactions and remains difficult to measure experimentally. We present a first step to quantify polarization on even gold (Au) surfaces in contact with water and with aqueous solutions of peptides of different charge state (A3 and Flg-Na3) by molecular dynamics simulation in all-atomic resolution and a posteriori computation of the image potential. Attractive polarization scales with the magnitude of atomic charges and with the length of multi-poles in the aqueous phase such as the distance between cationic and anionic groups. The polarization energy per surface area is similar on aqueous Au {1 1 1} and Au {1 0 0} interfaces of approximately −50 mJ m −2 and decreases to −70 mJ m −2 in the presence of charged peptides. In molecular terms, the polarization energy corresponds to −2.3 and −0.1 kJ mol −1 for water in the first and second molecular layers on the metal surface, and to between −40 and 0 kJ mol −1 for individual amino acids in the peptides depending on the charge state, multi-pole length and proximity to the surface. The net contribution of polarization to peptide adsorption on the metal surface is determined by the balance between polarization by the peptide and loss of polarization by replaced surface-bound water. On metal surfaces with significant epitaxial attraction of peptides such as Au {1 1 1}, polarization contributes only 10–20% to total adsorption related to similar polarity of water and of amino acids. On metal surfaces with weak epitaxial attraction of peptides such as Au {1 0 0}, polarization is a major contribution to adsorption, especially for charged peptides (−80 kJ mol −1 for peptide Flg-Na 3 ). A remaining water interlayer between the metal surface and the peptide then reduces losses in polarization energy by replaced surface-bound water. Computed polarization energies are sensitive to the precise location of the image plane (within tenths of Angstroms near the jellium edge). The computational method can be extended to complex nanometre and micrometer-size surface topologies.
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Shi, Linquan, i Qiang Li. "Numerical simulation and experimental study of contact thermal resistance under high temperature conditions". Thermal Science and Engineering 5, nr 1 (27.02.2022): 1. http://dx.doi.org/10.24294/tse.v5i1.1523.
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Contact thermal resistance is an important indicator of the efficiency of heat transfer between contact interfaces.The contact thermal resistance between the interfaces of superalloy GH4169 in high temperature was investigated byusing ANSYS. The real surface morphology of superalloy was obtained with optical microscope, and its surface modelwas reconstructed in ANSYS. Based on the theory of structural mechanics, the elastoplastic deformation of the microstructure of the contact interface is simulated, and analyzed and obtained the contact thermal resistance between contactinterfaces. The effect of interface temperature on the radiative heat transfer between the contact interfaces was studied.At the same time, the impact of radiation heat transfer between contact interfaces in high temperature is considered.Finally, it was tested by using an experimental test device. The result show that the maximum deviation between thecontact thermal resistance and the contact thermal resistance was 12.60%, and the contact thermal resistance betweensuperalloy interfaces decreases with the increase of interface temperature and contact pressure; the contact interfacetemperature difference increases first and then decreases with the increase of interface temperature.
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Pitanga, Heraldo Nunes, Orencio Monje Vilar i Jean-Pierre Gourc. "Wear resistance of geosynthetic interfaces constituted by geomembranes and geospacers". Rem: Revista Escola de Minas 66, nr 2 (czerwiec 2013): 227–32. http://dx.doi.org/10.1590/s0370-44672013000200014.
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This article presents the results of an experimental study which aimed to evaluate the effect of surface wear on the friction properties of geosynthetic interfaces constituted of geomembranes and geospacers. The tests were performed in ramp test device, and the results showed the different sensitivities of the interfaces to the wear process. For the particular types of interfaces considered in the experiment, the surface wear can increase, decrease or maintain the original friction properties of the geosynthetic interface, with direct effects on the stability under service condition.
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Alvarado, Omar, Gonzalo R. Quezada, Jorge H. Saavedra, Roberto E. Rozas i Pedro G. Toledo. "Species Surface Distribution and Surface Tension of Aqueous Solutions of MIBC and NaCl Using Molecular Dynamics Simulations". Polymers 14, nr 10 (12.05.2022): 1967. http://dx.doi.org/10.3390/polym14101967.
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Methyl isobutyl carbinol (MIBC) is a high-performance surfactant with unusual interfacial properties much appreciated in industrial applications, particularly in mineral flotation. In this study, the structure of air–liquid interfaces of aqueous solutions of MIBC-NaCl is determined by using molecular dynamics simulations employing polarizable and nonpolarizable force fields. Density profiles at the interfaces and surface tension for a wide range of MIBC concentrations reveal the key role of polarizability in determining the surface solvation of Cl− ions and the expulsion of non-polarizable Na+ ions from the interface to the liquid bulk, in agreement with spectroscopic experiments. The orientation of MIBC molecules at the water liquid–vapor interface changes as the concentration of MIBC increases, from parallel to the interface to perpendicular, leading to a well-packed monolayer. Surface tension curves of fresh water and aqueous NaCl solutions in the presence of MIBC intersect at a reproducible surfactant concentration for a wide range of salt concentrations. The simulation results for a 1 M NaCl aqueous solution with polarizable water and ions closely capture the MIBC concentration at the intercept. The increase in surface tension of the aqueous MIBC/NaCl mixture below the concentration of MIBC at the intersection seems to originate in a disturbance of the interfacial hydrogen bonding structure of the surface liquid water caused by Na+ ions acting at a distance and not by its presence on the interface.
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Yao, Qizhou, i Jianmin Qu. "Interfacial Versus Cohesive Failure on Polymer-Metal Interfaces in Electronic Packaging—Effects of Interface Roughness". Journal of Electronic Packaging 124, nr 2 (2.05.2002): 127–34. http://dx.doi.org/10.1115/1.1459470.
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Debonding of polymer-metal interfaces often involves both interfacial and cohesive failure. Since the cohesive strength of polymers is usually much greater than the polymer-metal interfacial strength, cohesive failure near the interface is usually desired for enhancing the interfacial adhesion. Roughened surfaces generally produce more cohesive failure; therefore, they are used commonly in practice to obtain better adhesion. This paper develops a fracture mechanics model that can be used to quantitatively predict the amount of cohesive failure once the surface roughness data are given. An epoxy/Al interface was investigated using this fracture mechanics model. The predicted amount of cohesive failure as a function of surface roughness compares very well with the experimentally measured values. It is believed that this model can be extended to other polymer–metal interfaces. Contributed by the Electronic and Photonic Packaging Division for publication in the JOURNAL OF ELECTRONIC PACKAGING. Manuscript received by the EPPD.
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Kim, Jaehyeon, Fujia Zhao, Shan Zhou, Kaustubh S. Panse i Yingjie Zhang. "Probing Molecular Structures at Electrified Interfaces Using in-Situ Surface-Enhanced Raman Spectroscopy". ECS Meeting Abstracts MA2023-01, nr 46 (28.08.2023): 2495. http://dx.doi.org/10.1149/ma2023-01462495mtgabs.
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The molecular scale understanding of electrode-electrolyte interfaces is significant, as interfacial molecular structures play a critical role in determining various properties such as capacitance and catalytic activity. However, the limited understanding exists on the interfaces, especially at a molecular level, due to difficulties to selectively probe the interfaces without an interference from the bulk. In this talk, I will present our recent observations on molecular configurations at electrified interfaces using in-situ surface-enhanced Raman spectroscopy (SERS). To be specific, we study interfaces of ionic liquids and aqueous electrolytes, considering they are promising candidates for various electrochemical applications. Our SERS spectra display a strong enough interface-sensitivity providing comprehensive information on a potential-dependence of ion configurations such as molecular position and orientation. We expect the molecular scale understandings provided by our studies are beneficial to a wide range of electrochemical applications including supercapacitors, batteries, and electrocatalysts.