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Showing papers on "Surface roughness published in 1983"


Journal ArticleDOI
TL;DR: In this paper, a theory for laser-induced periodic surface structure was developed by associating each Fourier component of induced structure with the corresponding Fourier components of inhomogeneous energy deposition just beneath the surface.
Abstract: We develop a theory for laser-induced periodic surface structure by associating each Fourier component of induced structure with the corresponding Fourier component of inhomogeneous energy deposition just beneath the surface. We assume that surface roughness, confined to a region of height much less than the wavelength of light, is responsible for the symmetry breaking leading to this inhomogeneous deposition; we find strong peaks in this deposition in Fourier space, which leads to predictions of induced fringe patterns with spacing and orientation dependent on the angle of incidence and polarization of the damaging beam. The nature of the generated electromagnetic field structures and their relation to the simple "surface-scattered wave" model for periodic surface damage are discussed. Our calculation, which is for arbitrary angle of incidence and polarization, applies a new approach to the electrodynamics of randomly rough surfaces, introducing a variational principle to deal with the longitudinal fields responsible for local field, or "depolarization," corrections. For a $p$-polarized damaging beam our results depend on shape and filling factors of the surface roughness, but for $s$-polarized light they are essentially independent of these generally unknown parameters; thus an unambiguous comparison of our theory with experiment is possible.

1,144 citations


Journal ArticleDOI
TL;DR: It is shown that errors can occur in calculating the true rms surface roughness from actual TIS measurements; ways to correct these errors are discussed.
Abstract: Previously published vector equations describing angle-resolved scattering from single-layer- and multilayer-coated optics have been integrated numerically and analytically over all angles in the reflecting hemisphere to obtain numerical results and analytical expressions for total integrated scattering (TIS). The effects of correlation length, polarization, angle of incidence, roughness height distribution, scattered light missed by the collecting hemisphere, and roughness cross-correlation properties of the multilayer stack on the TIS expression are considered. Background material on TIS from optics coated with single opaque reflecting layers is given for completeness and comparison to corresponding multilayer TIS results. It is shown that errors can occur in calculating the true rms surface roughness from actual TIS measurements; ways to correct these errors are discussed.

279 citations


Journal ArticleDOI
TL;DR: In this article, an experiment on remote sensing of soil moisture content was conducted over bare fields with microwave radiometers at the frequencies of 1.4, 5, and 10.7 GHz, during July-September of 1981.
Abstract: An experiment on remote sensing of soil moisture content was conducted over bare fields with microwave radiometers at the frequencies of 1.4, 5, and 10.7 GHz, during July-September of 1981. Three bare fields with different surface roughnesses and soil textures were prepared for the experiment. Ground-truth acquisition of soil temperatures and moisture contents for 5 layers down to the depths of 15 cm was made concurrently with radiometric measurements. The experimental results show that the effect of surface roughness is to increase the soil's brightness temperature and to reduce the slope of regression between brightness temperature and moisture content. The slopes of regression for soils with different textures are found to be comparable and the effect of soil texture is reflected in the difference of regression line intercepts at brightness-temperature axis. The result is consistent with laboratory measurement of soil's dielectric permittivity. Measurements on wet smooth bare fields give lower brightness temperatures at 5 than at 1.4 GHz. This phenomenon is not expected from current radiative transfer theory, using laboratory measurements of the relationship between dielectric permittivity and moisture content for different soil-water mixtures at frequencies of <5 GHz.

224 citations


Journal ArticleDOI
TL;DR: In this paper, a severe influence of insufficient buffer capacity in potentiodynamic surface oxide formation and reduction is experimentally shown, discussed and explained, and it is suggested that the onset of oxide II formation can be used for surface roughness determinations.

222 citations


Journal ArticleDOI
TL;DR: In this paper, the concept of roughness-induced crack closure is utilized to explain the role of prior austenite grain size and pearlite interlamellar spacing on near-threshold fatigue crack propagation in fully pearlitic eutectoid steel tested at low and high stress ratio in lab air and purified helium.
Abstract: The concept of roughness-induced crack closure is utilized to explain the role of prior austenite grain size and pearlite interlamellar spacing on near-threshold fatigue crack propagation in fully pearlitic eutectoid steel tested at low and high stress ratio in lab air and purified helium. It is shown that at low load ratios, near-threshold growth rates are significantly reduced for coarse-grained microstructures, compared to fine-grained at constant yield strength, due to roughness-induced crack closure. Using roughness-profile microscopy, it was found that fracture surface roughness near threshold scaled with grain size and inversely with yield strength, macroscopic roughnesses at threshold being considerably larger than the conventionally calculated cyclic crack tip opening displacement. Auger analysis of near-threshold corrosion products showed it to be iron oxide; the oxide thickness was seen to be decreased by increased stress ratio. The significance of this model to near-threshold fatigue crack growth behavior, in terms of load ratio, microstructure, and environment is discussed.

180 citations


Journal ArticleDOI
TL;DR: In this paper, the authors studied the charge accumulation and its mechanisms based on the experiments of post and conical epoxy spacers subjected to high dc voltages in compressed SF 6 gas.
Abstract: The charge accumulation and its mechanisms are studied based on the experiments of post and conical epoxy spacers subjected to high dc voltages in compressed SF 6 gas. The charge measurement is performed using electrostatic probe and dust figure techniques. The charge accumulation is strongly influenced by the surface condition of epoxy spacer. Heterocharge deposits locally on the surface of untreated spacer. The flashover voltage of highly charged spacer decreases considerably at the time of polarity reversal. In the case of epoxy surface treated with horning, only a small quantity of charge is deposited uniformly on the surface of spacer. The mechanism of inhomogeneous surface conduction is suggested by the local surface charging on the untreated spacer. Field emission is also found as the other charging mechanism on the conical spacer set in rough finish electrode system.

156 citations


Journal ArticleDOI
TL;DR: In this paper, high resolution angularly resolved time of flight distributions are presented for a supersonic argon beam scattering from a clean well-characterized Pt(111) single crystal.
Abstract: High resolution angularly resolved time of flight distributions are presented for a supersonic argon beam scattering from a clean well‐characterized Pt(111) single crystal. A novel presentation of the resulting velocity and angular flux information in terms of iso‐flux contour maps in Cartesian velocity space allows the scattering process to be decomposed into three mutually independent directions defined by the surface normal (z), parallel to the surface and in the scattering plane (y), and parallel to the surface but perpendicular to y and z(x). The iso‐flux contour maps appear as nested ovals with principal axes oriented parallel to the above defined directions; axis length decreases in the order z, y, x. The corresponding variances in the x, y, and z velocities vary directly with the surface temperature. Three beam energy regimes are evident and are discussed in terms of the diminishing effect of the attractive well which occurs for increasing beam energies and the increasing effect of short range phenomena prevalent at high incident beam energies. Accomodation coefficients were defined and measured for the y and z directions and were 0.1 and 0.45, respectively, indicating the degree to which parallel and perpendicular momenta are not conserved in a single collision. Geometric scattering by instantaneous surface roughness is experimentally shown to be negligible for this system for beam energies <20 000 K indicating that the scattering is by the finite momentum of the surface.

136 citations


Journal ArticleDOI
TL;DR: In this article, the microwave emission from the ocean surface was used to determine the optimum electromagnetic wavelength for measuring salinity, achieving a state-of-the-art accuracy of 240 parts per million.
Abstract: Parametric calculations of the microwave emission from the ocean surface are presented to determine the optimum electromagnetic wavelength for measuring salinity. At 800 MHz, a target accuracy of 240 parts per million is within the state of the art provided that emission due to surface roughness is negligible, or correctable, and that the error resulting from galactic radiation can be removed using an upward-looking antenna. Examples of salinity measurements relevant to physical oceanography are presented, and a possible spacecraft University of Massachusetts, Amherst, MA 01003.system is discussed.

132 citations


Journal ArticleDOI
TL;DR: In this article, the authors highlight the problems associated with interpreting data on the resistivity of thin thin films and point out that extreme care must be taken in analysing data and a thorough study should be made of the morphology of the films from which data are taken.

119 citations


Journal ArticleDOI
01 Nov 1983-Polymer
TL;DR: In this paper, the growth faces of polyethylene are analysed in terms of a roughness which, on the {110} faces, increases progressively over a temperature range of about 100°C.

113 citations


Journal ArticleDOI
R. G. Cox1
TL;DR: In this article, the equilibrium configurations of a liquid spreading on a rough solid surface are derived by making expansions in terms of the characteristic slope e of the surface roughness, which is assumed to be very small.
Abstract: The equilibrium configurations of a liquid spreading on a rough solid surface are derived by making expansions in terms of the characteristic slope e of the surface roughness, which is assumed to be very small. It is also assumed that the microscopic contact angle is a constant and that the liquid–air interface is planar at large distances from the contact line. Expressions for the value of the macroscopic contact angle and a discussion of the existence of contact-angle hysteresis and of stick-jump behaviour of the contact line are given for (i) surfaces with parallel grooves, (ii) surfaces with periodicity in two perpendicular directions and (iii) general non-period surfaces.

Journal ArticleDOI
TL;DR: In this article, a roughness height definition is developed and subsequently used to reanalyze the data base for wind tunnel, ballistic range, and free-flight experiments, and a nosetip correlation model bascd in part on the critical Reynolds number approach as well as on a re-cvaluation of experimental data.
Abstract: HE re-entry physics community has for many years recognized the crucial role that nosetip transition plays in re-entry vehicle performance. The onset and progression of the transition front are governed by complex fluid mechanical processes that depend critically on surface roughness, wall temperature, nose-tip geometry, angle of attack, and freestream conditions. The flight analyst must make preflight predktioil~ and postflight data comparisons incorporating a suitable transition model in shape-change code computations. Such calculations of vehicle drag and surface recession contours are sensitive to both the transition correlation and the surface roughness. This sensitivity of nosetip shape change is dramatic, as witnessed by calculated that show that moderate changes in either the surface roughness height (keeping the correlation fixed) or the transition correlation slcne (keeping the roughness fixed) lead to markedly different transition-onset altitudes and nosetip shapes. These vehicle shape-change effects, which are in direct response to the transition process, are further compounded by the inherent stochastic behavior of boundary-layer transition and the .random nature of nosetip-surface roughness. Resulting transition front asymmetries can promote asymmetric nosetip shapes that cause substantial vehicle trim dispersions. The importance of the two key aspects of nose:ip transition, i.e., the transition correlation model and the roughness character, has, of course, been pointed out by previous investigators. Although individual experiments or analyses have been self-contained and have adequately described most of the observed behavior, there still exists in the literature a lack of consistency among the various studies with regard to 1) roughness height definition, 2) transition point identification, and 3) validity and/or interpretation of specific experimental transition data. These deficiencies have limited the extent to which previo:~~ studies can be applied and have provided the primary motivation for the present investigation. The current paper, which essentially summarizes results obtained from the detailed study rer~orted in Ref. 2, reviews previous research on nosetip transition, re-examines surface roughness characterization, and describes a nosetip correlation model bascd in part on thc critical Reynolds number approach as well as on a re.cvaluation of experimental data. In the sections that follow, the emphasis will be upon the consistent evaluation and detailed review of the ground-test data on nosetip transition. A common roughness height definition is developed and subsequently used to reanalyze the data base for wind tunnel, ballistic range, and free-flight experiments.

Journal ArticleDOI
TL;DR: In this paper, a complete picture of this radiation process includes hot electrons, which excite surface electromagnetic resonances, which are in turn coupled to external radiation through surface roughness.
Abstract: Metal-insulator-metal tunnel junctions emit optical radiation when biased at voltages in the range 2-4 V. We argue that a complete picture of this radiation process includes hot electrons, which excite surface electromagnetic resonances, which are in turn coupled to external radiation through surface roughness. This picture is supported by measurements of the temperature and second-metal-electrode thickness dependence of the emission intensities, and by light emission from surface plasmons excited by optical pumping and by charge injection.

Journal ArticleDOI
TL;DR: In this article, the results of a surface-layer experiment near the Cabauw meteorological mast were discussed, where the authors measured momentum, heat and moisture fluxes at two heights, namely, 3.5 and 22.5 m. The measurements also included the mean wind speed and mean temperature profiles.
Abstract: This paper discusses the results of a surface-layer experiment near the Cabauw meteorological mast. We measured momentum, heat and moisture fluxes at two heights, namely, 3.5 and 22.5 m. The measurements also include the mean wind speed and mean temperature profiles. The purpose was to investigate surface-layer similarity laws under nonideal fetch conditions. We found that under such conditions, the shell stress increases with height because of obstacles upstream. As a consequence flux-profile relationships differ from those over uniform terrain. It is shown that these deviations imply a slow relaxation in the exchange coefficient for heat and momentum over a terrain with changing surface roughness. Furthermore, we found that horizontal velocity fluctuations scale on a friction velocity representative of a large area. On the other hand, vertical velocity fluctuations scale on the local friction velocity.

Journal ArticleDOI
01 Apr 1983
TL;DR: In this paper, the effect of surface roughness on spreading rates has been analyzed using a model in which a liquid drop spreads over the surface of a porous medium filled with the same liquid.
Abstract: The effect of surface roughness on spreading rates has been analyzed using a model in which a liquid drop spreads over the surface of a porous medium filled with the same liquid. The equations of motion in the drop are simplified with the lubrication theory approximation and then solved for both zero and small but nonzero contact angles by the method of matched asymptotic expansions. Although the largest pressure gradients and velocity gradients occur near the contact line at the drop periphery, behavior in this region is not singular as found in previous analysis of spreading on perfectly smooth surfaces. The reason no singularities exist is that flow occurs in the “porous medium” underlying the drop, i.e., the region of surface irregularities which is present for all real surfaces. Because the solution is not valid in the initial stages of spreading where experimental data on spreading rates are available, a quantitative comparison of theory and experiment cannot be made at present. The theory does, however, explain all qualitative features observed for spreading drops, e.g., the increase in spreading rate with increasing roughness and the frequent appearance of apparent contact angles significantly different from equilibrium contact angles.

Patent
28 Mar 1983
TL;DR: In this paper, an optical reflectance method for rapid and simultaneous determination of surface roughness and structure of silicon films deposited by chemical vapor deposition is described, where the magnitude of the reflectance of polycrystalline silicon films at a wavelength of about 280 nm can be used directly as a quantitative measure of film surface roughs.
Abstract: This disclosure describes an optical reflectance method for rapid and simultaneous determination of surface roughness and structure of silicon films deposited by chemical vapor deposition. The magnitude of the reflectance of polycrystalline silicon films at a wavelength of about 280 nm can be used directly as a quantitative measure of film surface roughness. The magnitude of the reflectance of as-deposited amorphous or mixed amorphous-polycrystalline silicon films at a wavelength of about 400 nm can be used as a measure of the combined surface roughness and amorphism of the films. Other materials such as metals, alloys and silicides used in semiconductor technology may be evaluated with respect to surface roughness in a similar manner.

Journal ArticleDOI
TL;DR: In this paper, it is shown that σXM is probably overestimated in calculations, but it cannot be neglected, and that all discussions neglecting it should retain their qualitative validity.

Patent
09 Mar 1983
TL;DR: In this paper, the surface roughness of a super-high density magnetic recording medium (SHDM) is defined as the area where two or more depressions are contiguous to each other, and a covering layer composed of a lubricant is formed on the surface of the layer.
Abstract: A laminated film for a super-high density magnetic recording medium, comprises (A) a layer 5 composed of a thermoplastic resin and (B) a layer 1 of a thermoplastic resin containing fine particles therein. In this laminated film, the outer surface of the layer (A) has a surface roughness of less than 0.005µ as expressed as the Ra value, and the outer surface of the layer (B) has a surface roughness of 0.005 to 0.040µ as expressed as the Ra value. The outer surface of the layer (B) has either (i) a plurality of depressions and a plurality of protrusions, which are formed thereon in a configuration such that at least one protrusion 3 exists within each depression 2 or at least one protrusion exists in the area where two or more depressions are contiguous to each other, or (ii) protrusions on a flat plane and a covering layer (C) composed of a lubricant, which is formed on the surface of the layer (B). This covering layer (C) may be formed on the surface having the above-mentioned depressions 2 and protrusions 3. The covering layer (C) is a continuous film layer or a discontinuous film layer formed of worm-like nodules. When a ferromagnetic metan thin film is formed on the surface of the layer (A) by vacuum evaporation and a protective film layer is formed on this thin film, there is obtained a vacuum-deposited video tape excellent in the running property and electromagnetic transformation performances. In this vacuum-deposited video tape, the transfer of the surface configuration due to the coarseness of the running surface can be prevented.


Journal ArticleDOI
TL;DR: In this paper, a geometric adaptive control system to compensate for errors in the finished surface due to tool deflection generated by milling operations is presented, and the effects of cutting forces upon the shape of the final surface are analyzed.
Abstract: Adaptive control to keep the accuracy of the shape of a workpiece within acceptable levels by altering the numerical control commands according to variations of manufacturing process parameters is called “geometric adaptive control.” In this paper, a geometric adaptive control system to compensate for errors in the finished surface due to tool deflection generated by milling operations is presented. The effects of cutting forces upon the shape of the finished surface are analyzed, and the composition of the system is discussed. In the system, the location error and the waviness error at the finished surface are evaluated from the sensed bending moments in the tool. These two errors are compensated for by shifting the tool path and by adjusting the feedrate, respectively. It is verified by experiments that the accuracy of the finished surface is improved significantly by using the system described in cases where the depth of cut varies. Geometric adaptive control is useful even when a workpiece is machined by both rough and finish cuts.

Journal ArticleDOI
TL;DR: In this paper, the frequency dependence of the surface roughness effect was relatively weak when compared with that of the vegetation effect, and it was found that an increase in roughness increased the brightness temperature of soils and reduced the slope of regression between brightness temperature and soil moisture content.


Journal ArticleDOI
TL;DR: On the other hand, surface enhanced Raman scattering (SERS) as mentioned in this paper has been shown to be a major contributor to surface optical resonances on Cu, Ag, Au, and Li.


Journal ArticleDOI
TL;DR: In this paper, the smoothing method is used to find the first two moments, i.e., the mean and the two-point two-time correlation function, of the field scattered by a rough surface.
Abstract: The smoothing method is used to find the first two moments, i.e., the mean and the two‐point two‐time correlation function, of the field scattered by a rough surface. The results are expressed in terms of a reflection coefficient and a differential scattering coefficient. They are compared with those found by several other methods.

Journal ArticleDOI
TL;DR: The surface roughness of polished porcelain was investigated and the results showed that no significant differences between the two polishing methods used were found.
Abstract: The surface roughness of polished porcelain was investigated. The results showed that no significant differences between the two polishing methods used were found. The two evaluation methods, surface roughness measurements and scanning electron microscopy (SEM), are discussed and some recommendations are given.


Journal ArticleDOI
TL;DR: The surface roughness patterns caused by internal waves in Georgia Strait on the west coast of Canada were used as an imagery target for the SEASAT synthetic aperture radar (SAR) on July 30, 1978 as discussed by the authors.
Abstract: The surface roughness patterns caused by internal waves in Georgia Strait on the west coast of Canada were used as an imagery target for the SEASAT synthetic aperture radar (SAR) on July 30, 1978. In these patterns there is strong modulation of short surface waves including the Bragg wavelength for resonant microwave reflection. In the sheltered waters of the strait, the complicating effects of longer waves are greatly reduced. The roughness patterns were also observed with an airborne SAR, by aerial photography, and by shipborne surface roughness and subsurface current measurements. The data show the response of the SAR's to the anisotropic roughness patterns measured by the ship. The SAR signal intensity is shown to be moderately correlated with Bragg wave or total roughness energy, but not with the facet area aligned to give specular reflection.

Journal ArticleDOI
TL;DR: In this paper, the surface enhanced Raman scattering has been studied for the Ag-pyridine system and the maximum enhancement for an average surface roughness of about 1000 A was found.

Journal ArticleDOI
TL;DR: In this article, high-resolution TEM cross sections of the Si-SiO2 interface and detailed temperature dependent electronic and magnetic transport measurements are compared to a model containing terms for surface roughness and impurity scattering including carrier screening.
Abstract: Scattering of inversion layer electrons at the oxide semiconductor interface is a major source of mobility degradation in MOSFETs. We have studied, on the same sample, high resolution TEM cross sections of the Si–SiO2 interface and detailed temperature dependent electronic and magnetic transport measurements. The expeirmental mobility data are compared to a model containing terms for surface roughness and impurity scattering including carrier screening. The statistical properties of the interface fluctuations appear as parameters which are adjusted to fit the transport data. While the TEM pictures indicated an interfacial boundary which deviated by only one atomic layer, an assumed peak‐to‐peak deviation of approximately five atomic layers is required to fit the experimental mobility. Thus, while the overall comparison of the surface parameters suggests that roughness scattering is a plausible mechanism, close agreement between the theory and experiment is not obtained.