bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction Between Shaped Beams and an Infinite Cylinder, including a discussion of Gaussian beams
Authors: Gouesbet Gérard , Gréhan Gérard 
Published: December 2004

AbstractThe theory of interaction between a shaped beam and an infinite cylinder arbitrarily located in it is presented. The same approach as for the generalized Lorenz‐Mie theory is first used. In particular, variable separability is assumed in solving the wave equation. The special case of Gaussian beams, however, implies that, unexpectedly, a special class of non‐separable scalar potentials is required for some kinds of beams.
A Theoretical and Experimental Study of the Total Light Scattering Technique for particle size analysis
Authors: Wang Nai‐ning , Zheng Gang , Cai Xiao‐shu 
Published: December 2004

AbstractThe total light scattering method for particle size measurement has a series of outstanding features, e.g. very simple instrumental arrangement, no serious requirements for its optical, photodetecting and electronic systems and its ease of use. Nevertheless, some problems still remain unsolved which should be dealt with to improve its further applications. An improvement has been made in this work. Comprehensive theoretical studies showed that this method is applicable to particle size analysis in the range 0.1–10 μm, i.e. for those particles whose diameter lies between the lower limit of the diffraction method and the upper limit of photon correlation spectroscopic (PCS) technique. Experimental studies with different monodisperse polystyrene latex spheres as standard reference material give good agreement with their nominal values.
Small Angle X‐Ray Scattering of Hematite Aggregates
Authors: Amal Rose , Gazeau Didier , Waite T. David 
Published: December 2004

AbstractSmall angle X‐ray scattering has been utilised to study the structure of hematite aggregates. The small angle X‐ray scattering (SAXS) spectra obtained provided insight into structure of the hematite aggregates and the size of the primary particles. The structural analysis results obtained by SAXS are consistent with previous results obtained from static light scattering studies. Both techniques indicate that the mass fractal dimensions of hematite aggregates are markedly higher than those obtained for other particle systems.
Effect of Laser Beam Dimensions on Electrophoretic Mobility Measurements
Authors: Finsy Robert , Xu Renliang , Deriemaeker Luc 
Published: December 2004

AbstractThe effect of the finite dimension of the measuring probe, i. e. the laser beam width, on the electrophoretic mobility distribution as determined by electrophoretic light scattering in closed capillary cells is presented on a quantitative basis. The experimental mobility broadening as a function of the probe position in the capillary is in agreement with the broadening expected from the laser beam waist. A strategy for the accurate determination of average mobility and mobility distributions is proposed.
Influence of Porosity on the Electrical Sensing Zone and Laser Diffraction Sizing of Silicas. A collaborative study
Authors: Michoel Armand , De Jaeger Nicolas , Sneyers Rik , De Wispelaere Walter , Geladeé Erik , Kern Jo , Gorter Wim , van Amsterdam Peter , Tandt Youry Den , Houtmeyers Eddy , van Cotthem Luc 
Published: December 2004

AbstractThe objective of a continuing study by the Belgian Particle Technology Group involves difficulties in practical size determinations. This part describes the behaviour of silicas with different porosities during sizing by electrical sensing zone and laser diffraction methods. Anisotropy and porosity were identified to be important particle characteristics in understanding the differences between the two methods. Especially large pore diameters and pore volumes were found to be responsible for shifts in size distribution of 50 to 100%. The use of optical values and optical models was shown to influence these shifts considerably. In the case of spherical silica particles with moderate porosity, no significant differences could be found between the two sizing methods.
Investigation of the Behaviour of Powders under and after Consolidation
Authors: Maltby Lars P. , Enstad Gisle G. , de Selva Sunil R. 
Published: December 2004

AbstractA biaxial tester was utilized in order to characterize mechanical powder behaviour. Tests were aimed at characterizing the virgin consolidation behaviour of CRM 116 limestone powder, standardized by the Community Bureau of Reference (BCR). The tests indicated that the virgin consolidation behaviour of the powder can be represented by means of topographic maps and surface plots in the principal stress space irrespective of the consolidation stress paths. Resulting strains and bulk densities can also be represented in the same manner. Reloading tests were also carried out on samples consolidated by following different stress paths (consolidation procedures). By applying stresses to the previously consolidated samples and determination of points of initial plastic deformations, the yield surface for each specific type of consolidation was drawn. These tests revealed anisotropic behaviour of the powder, depending on the type of consolidation.
Lattice models, packing density, and Boltzmann‐like distribution of cavities in proteins
Authors: Rashin Alexander A. , Rashin Abraham H. L. 
Published: December 2004

AbstractA model reproducing the experimental Boltzmann‐like distribution of empty cavity sizes in proteins is introduced. Proteins are represented by lattices of different dimensionalities, corresponding to different numbers of nearest neighbor contacts. Small cavities emerge and join into larger ones in a random process that can be related to random mutations. Simulations of cavity creation are performed under the constraint of a limiting total packing density. Cavities sufficiently large (20 Å3 or more), that they might accommodate at least one additional methyl group produced by a mutation, are counted and compared to the distribution of cavities according to their sizes from protein statistics. The distributions calculated with this very simple model within a realistic range of packing densities are in good agreement with the empirical cavity distribution. The results suggest that the Boltzmann‐like distribution of cavities in proteins might be affected by a mechanism controlled by limiting packing density and maximum allowed protein destabilization. This supports an earlier suggestion that the agreement between the free energies of cavity formation from the mutational experiments and from the statistics of the empty cavity distribution in X‐ray protein structures is nonfortuitous. A possible relation of the suggested model to the Boltzmann hypothesis is discussed. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Soldering external connections to thin film systems
Authors: Keller H. N. , Morabito J. M. 
Published: December 2004

AbstractExternal connections to thin film hybrid integrated circuits (HICs) by solder bonding have several advantages over those bonded by solid phase or thermocompression bonding. This paper reviews these advantages and discusses the parameters necessary for high strength, reliable solder joints to thin films. Dissolution of the soluble thin film(s) into solder limits the solder reflow times. Recent work has shown that dissolution rates of thin films in solder depend primarily on the degree of thin film heat treatment prior to soldering, substrate surface texture, and the method of thin film deposition. Auger in‐depth profiling data show that alloy formation and internal oxidation reduces film dissolution during solder reflow. Metallographic sectioning and chemical analysis are used to identify weak solder bond interfaces which result from intermetallic formation. Tin from the solder diffuses rapidly and reacts with soluble metals such as gold, palladium and copper to form brittle intermetallics such as AuSn4, PdSn4 and Cu6Sn5. Intermetallic formation between the solder and the thin film systems of interest can affect joint strength and reliability.
Studies of oxide supported metal clusters
Authors: Watters Kenneth L. 
Published: December 2004

AbstractThe metal cluster carbonyl compounds, Rh6(CO)16 and [Pt3(CO)6] (n = 5,6) have been deposited from solution onto alumina and silica supports. Exposure to air results in decarbonylation of the surface supported compounds in each case. Gas adsoprtion and IR measurements for the alumina supported rhodium material indicate a unique and interesting chemistry in which CO and oxygen react with a surface species to form CO2 and the surface rhodium material is reversibly converted from a fully carbonylated form [apparently Rh6(CO)16] to a fully oxygenated (decarbonylated) form which may retain the Rh6 cluster integrity.The supported platinum complexes displayed a more conventional chemistry. After deposition on alumina or silica they could be decarbonylated in air. Exposure to CO failed to regenerate the starting material, but behaviour consistent with that reported for conventional reduced Pt on alumina or silica was observed.
SIMS matrix effects in Alx Ga1 – xAs: Influence of instrumental parameters
Authors: Galuska A. A. , Wallace W. O. , Marquez N. , Uht J. 
Published: December 2004

AbstractThe influence of instrumental parameters on the matrix effects (ion and sputtering yield variations) observed in AlxGa1 – xAs are critically evaluated. Ion and sputtering yield data from three different SIMS instruments (ARL IMMA, Cameca IMS‐3F and Atomika SIMS) are examined. The influence of primary ion (O2 +) energy and incident angle on the extent of surface oxidation was examined using AES. Although relative ion yields varied linearly with the matrix composition in all instances, these ion yield variations differed greatly (a factor of 50) between instruments. These differences were attributed to differences in the surface oxygen concentrations produced by the SIMS instruments. AlAs was shown to be completely oxidized under each of the SIMS ion bombardment conditions. However, the oxygen levels incorporated in GaAs and the other Al poor specimens depended largely on the incident angle and to a lesser extent on the ion energy. Small incidence angles (normal incidence) promoted the most extensive oxidation of the Al‐poor specimens, resulting in the smallest ion yield variations with matrix. As with the relative ion yields, relative sputtering yields varied linearly with the matrix composition in all instances. However, in contrast to relative ion yields, the relative sputtering yields did not change significantly under the different instrumental conditions. It was concluded that incident angle and ion energy had approximately the same influence on the sputtering yields obtained from the reference and the sample matrices. Thus, the relative sputtering yields were insensitive to changes in these ion beam parameters.
Depth resolution improvements using specimen rotation during depth profiling
Authors: Geller Joseph D. , Veisfeld Nina 
Published: December 2004

AbstractIt has been well documented that depth resolution (interface width) degrades with depth when crystalline materials are sputtered by ion beams, whereas amorphous materials are less susceptible to this phenomenon.1 Several techniques have been employed to reduce this interface broadening problem. Amongst them have been reactive ion beam sputtering,2 ion sputtering with two ion beams at opposing angles,3,4 and finally, ion sputtering while the specimen is being mechanically rotated3,5,6. We elaborate upon this last technique, using a more stable sample rotation device, supporting Zalar's results that the depth resolution of a polycrystalline thin film material is nearly independent of depth. Further results indicate that the measured interface widths were independent of ion beam accelerating voltage between 1.0 and 3.0 keV only when sample rotation was applied; and that the loss of depth resolution near the specimen surface and within bulk occurs as a result of mono‐directional ion beam sputtering. We have also demonstrated that surface roughness can actually be reduced by rotation during sputtering, thereby restoring the interface depth resolution.
XPS study of metal/polymer interaction: Evaporated aluminum on polyvinyl alcohol polymer
Authors: Stoyanov P. , Akhter S. , White J. M. 
Published: December 2004

AbstractThe interaction between in situ evaporated aluminum and plyvinyl alcohol (PVA) polymer at 300 K was studied by XPS. The aluminum condenses on the PVA surface by a Volmer–Weber (clustering) mechanism; it takes about a 3.7 monolayer deposition to nucleate clusters sufficiently large to exhibit core binding energies characteristic of bulk metal. Changes in the lineshapes of the C 1s and O 1s peaks and the appearance of a shifted peak in the Al 2p region were interpreted in terms of Al interactions with the surface alcoholic group HCOH, resulting in the formation of an interfacial organometallic complex exhibiting a stoichiometry of 1:1:1.5 for Al, C and O. Polar angle‐resolved XPS measurements and differences in the attenuation factors of the signals from the complex show that the Al is on top and is closer to the oxygen atoms.
Electronic and structural characterization of electrochemically synthesized conducting polyaniline from XPS studies
Authors: Kumar S. N. , Bouyssoux G. , Gaillard F. 
Published: December 2004

AbstractWe report high‐resolution XPS data on three forms of the electrochemically synthesized polyaniline films: the highly conducting emeraldine salt form and the films obtained after KOH treatment and electrochemical reduction in HCI. The deconvoluted N 1s peaks in these films show clear evidence of the existence of the existence of four states of nitrogen, which are attributed to the amine, polaron and localized bipolaron defect configurations. The trends observed after the KOH treatment and electrochemical reduction in HCI in the N 1s spectra, plus the C 1s and O 1s peak shapes, support this assignment scheme.
A new approach in non‐destructive characterization and XY profilometry of coatings
Authors: Cazaux J. , Jbara O. , Thomas X. 
Published: December 2004

AbstractA scanning electron microscope equipped with an x‐ray detector has been used to characterize the thickness and elemental composition of coating on substrates. The proportionality between the x‐ray signal intensity and the thickness, t, of the coating has been established experimentally and explained by applying a formalism similar to that used in Auger analysis.The thicknesses under investigation range from that of Auger (∼ 3–4 nm) to a fraction of a micron. The accuracy of thickness determination (±5%) is mainly governed by the statistics when the operating conditions are optimized.The x‐ray profiles and images obtained by incident electron beam scanning allow a rapid evaluation (with two‐ or three‐dimensional representations) of the lateral thickness and compositional changes of the coatings. At the same time, the use of the ‘scatter diagram’ technique improves their quantitative interpretation.The lateral resolution (better than 1 μm) and limitation of the technique are discussed. Both academic and practical examples are used to illustrate its application.
Improvement of the AES detection limit for phosphorus in silicon by principal component analysis or spline smoothing
Authors: Procop M. , Weber E.‐H. 
Published: December 2004

AbstractThe detection limit of Auger electron spectroscopy (AES) can be improved by mathematical methods that reduce the influence of noise. We compared principal component analysis (PCA) and spline smoothing and applied them to the analysis of a phosphorus depth profile in silicon. Both methods yield similar results under typical conditions, namely detection limits of ∼0.04 at.% P compared with a limit of 0.09 at.% for the raw data. At a reduce signal‐to‐noise ratio, the PCA failed and the improvement by smoothing remained constant.
The interaction of water and Mn with surfaces of CaCO3: An XPS study
Authors: Baer D. R. , Blanchard D. L. , Engelhard M. H. , Zachara J. M. 
Published: December 2004

AbstractThis paper reports an examination of the chemistry of single‐crystal calcite (CaCO3) using x‐ray photoelectron spectroscopy (XPS). This calcite cleavage surface was examined as freshly opened in vacuum and after several different treatments, including exposure to water vapor, covered with different amounts of evaporated Mn, ion sputtered and immersed in pure water. Clean and ion‐sputtered calcite were not observed to react with water vapor. Ion sputtering caused significant changes to both oxygen and calcium bounding at the surface. However immersion of sputtered calcite in water caused removal of the sputter damage and produced an XPS spectrum nearly indistinguishable from that of the fresh cleavage surface. The shapes and positions of the Mn and O peaks in the spectra of CaCO3 with submonolayer coverages of Mn indicate partial oxiation of the metal as deposited presumably owing to reaction with the calcite surface. Immersion of the Mn‐coated calcite in water caused further changes in the Mn peak, suggesting additional oxidation of the Mn.
The oxidation and oxide overlayer stability of AgMn alloys
Authors: Mencer D. E. , Cocke D. L. , Yoon Cheonho 
Published: December 2004

AbstractThe oxidation of several compositions (5, 9 and 14% Mn) of polycrystalline Ag‐Mn alloys from room temperature to 650 °C in high vacuum and in 5 m Torr O2 has been investigated by x‐ray photoelectron spectroscopy (XPS). The behavior of the oxidation and the nature of the oxide films are controlled by tempearature, oxygen pressure, bulk alloy composition and the stability of the oxide overlayers. At low temperatures and pressures, the oxidation process is controlled by the relative free energies of oxide formation of the alloy components. At high temperatures the oxide of stabilities play a large role in determining the oxidation state of the oxide overlayer. The chemical state and the morphology of the oxide of manganese formed during the alloy oxidation has been examined. The chemical state and the morphology of the oxide overlayers have been studied by XPS, x‐ray diffraction (XRD) and scanning electron microscopy (SEM). The complex oxidation process has been delineated.
A marker technique to identify diffusing elements during initial reactions using ion scattering spectroscopy
Authors: Schmidt Michael T. , Wu Zhen , Osgood Richard M. 
Published: December 2004

AbstractA variation of classical marker techniques has been combined with low‐energy ion scattering spectroscopy (ISS) to study the diffusion of species during the initial formation of several reachted monolayers, allowing the study of thinner layers than standard marker techniques allow. Results are presented for the reaction of oxygen with GaAs under 248 nm laser illumination and at 400 °C, as well as for the well‐studied case of Ni oxidation at room information that can be obtained with his method. The results show that inward oxygen diffusion can be distinguished from outward metal diffusion as the reaction proceeds. This information is crucial for developing an understanding of reaction mechanisms in thin films.
Surface characterization of ruthenium‐exchanged Y‐zeolite used in ammonia synthesis
Authors: Wellenbüscher J. , Sauerland U. , Mahdi W. , Ertl G. , Schlögl R. 
Published: December 2004

AbstractNaY zeolite was cation exchanged with Ru and tested in ammonia synthesis at atmospheric pressure. Activities up to ∼10% of the commercial iron catalyst scaled by the active surface area were observed. Characterization of the zeolites with XPS was complemented with reference thermal desorption spectroscopy data on a polycrystalline Ru metal surface. The catalysts showed high thermal stability in in situ reduction–oxidation cycles. The chemical state of the Ru will be discussed. From shift measurements the Ru is metallic in the active state, but line shape arguments point to a cluster‐like particle morphology. The location of the Ru inside or outside the zeolite framework will be discussed.
Thermal and surface characterizations of 25.5 (wt.%) CeO2–2.5 Y2O3–72 ZrO2 fine powder
Authors: Ingo G. M. , Maschio R. Dal , Scoppio L. 
Published: December 2004

AbstractBy means of X‐ray photoelectron spectroscopy (XPS), simultaneous differential thermal analysis (DTA) and thermogravimetric analysis (TGA), changes of valence state and surface chemical composition of a 25.5 (wt.%) CeO2–2.5 Y2O3–72 ZrO2 fine powder have been studied as a function of temperature (up to 1550°C) and atmosphere (flowing 90% N2‐10% H2 and static air). The XPS results lead to the evaluation of the valence state of cerium, zirconium and yttrium, both in the starting powder and in thermal‐treated powders. The analysis of the characteristic satellite structures, binding energies and peak shapes of the Ce 3d spectra show that cerium in the starting powder is confirmed to be Ce(IV) with a small amount of Ce(III), and that after thermal treatment the cerium is either unaffected or partially or fully reduced to Ce(III). The DTA and TGA thermograms confirm this redox behaviour and disclose, for air treatment, the presence of a strong, sharp exothermic peak at ∼410°C, which is interpreted as being due to the oxidation of a small amount of Ce2O3. On the contrary, under reducing conditions in the temperature range 630–730°C, the powder is affected by a remarkable weight loss owing to the Ce(IV) reduction to Ce(III) oxide. The change of valence state of zirconium, due to the reduction of ZrO2 to ZrO2−x under reducing conditions at high temperature, has also been monitored by XPS. Furthermore, on high temperature (≥900°C)‐treated powders, XPS results show the occurrence of segregation phenomena of both bulk dissolved impurities, such as silicon, sodium, iron and aluminium, as well as yttrium stabilizing oxide. The Wagner two‐dimensional chemical state plots for silicon, sodium and aluminium indicate that the chemical nature of the segregated phase can be ascribed to a silicate of sodium and yttrium with the presence of aluminium at higher temperatures. The effect of the above‐mentioned chemical aspects on the final properties of sintered materials is also discussed.
High‐temperature oxidation of iron covered by electroless NiP coating: A GDOS depth profiling study
Authors: Weiss Zdeněk 
Published: December 2004

AbstractSteel samples coated by electroless nickel were annealed in air. Oxide growth kinetics and iron diffusion through the structure were investigated by glow discharge optical emission spectroscopy (GDOS) depth profiling. Protection against high‐temperature oxidation was found to be given mostly by the austenitic interdiffusion layer formed at the interface between the substrate and the NiP film during annealing of the sample, which acts as a diffusion barrier for diffusion of iron to the surface.