bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparative Study of Superplastic Deformation and Cavitation Failure in a Yttria Stabilized Zirconia and a Zirconia Alumina Composite
Authors: Chokshi A. H. , Schissler D. J. , Nieh T.-G. , Wadsworth J. 
Published: March 2011

ABSTRACTA fine grained yttria stabilized zirconia and a zirconia composite containing 20% alumina exhibit superplastic characteristics, with optimum elongations to failure of ≥500%. There is microstructural evidence for deformation enhanced grain growth and concurrent cavitation in both of these superplastic ceramics. Grain sizes after superplastic deformation may be several times larger than the initial grain size, and the level of cavitation can attain values as high as ≥30% under some experimental conditions. This report presents in a comparative format some recent experimental results on the microstructural aspects of superplastic deformation and concurrent cavitation in these superplastic ceramics.
Superplastic Deformation and Mechanisms of the Commercial Aluminium Alloy Al-4Cu-I.6Mg-0. 8Mn
Authors: Liu Yuwen , Yang Guang , Lian Jianshe , Zeng Xianwen 
Published: March 2011

ABSTRACTThe superplastic deformation behavior and mechanisms of commercial Al-4cu-1.6 Mg-0.0Mn have been studied, using tensile tests with microstructuraL observations being carried out by optical and transmission etectronmicroscopy. The results of tensile tests show that considerable superplasticflow can be obtained without any pretreatment to this atloy.The maximum elongaton achieved is 42096 and the strain rate sensitivity index, m, is 0.49. Microstructural analysis reveals that the dominant mechanism in the early stage of deformation is diffusion. As strain increases, grain-borundary sliding and grain rearrangment take the dominant part in thedeformation process, and diffusion becomes an accommodation mechanism. Second phase particles effectively restrict grain growth during deformation. Cavity initiation and growth during deformation are the direct cause of specimen failure.
Molecular Weight and Molecular Weight Distribution of Kraft Lignins
Authors: Schmidl Wolfgang , Dong Daojie , Fricke Arthur L. 
Published: March 2011

ABSTRACTKraft lignins are the lignin degradation products from kraft pulping. They are complex, heterogeneous polymers with some polar character. The molecular weight of kraft lignins greatly affect the physical properties of black liquors, and are of primary importance in separation from black liquor and in evaluating potential uses.Several purified kraft lignins from slash pine were analyzed for number average molecular weight by vapor pressure osmometry (VPO), for weight average molecular weight by low angle laser light scattering (LALLS), and for the molecular weight distribution by high temperature size exclusion chromatography (SEC). The lignins were run in Tetrahydrofuran (THF), N, N-Dimethyl Formamide (DMF), DMF with 0.1M LiBr, and pyridine at conditions above the Theta temperature. Experimental methods are discussed.The results show that VPO may be used to determine Mn for kraft lignins if the purity of the lignins and the identity of the impurities are known. LALLS can be used to determine Mw for kraft lignins if measurements are made at or above the Theta temperature of the lignin-solvent pair. SEC should be used at temperatures at, or above, the Theta temperature of the lignin-solvent pair. Size separation is highly dependent on the solvent used, and DMF is a much better solvent than THF for high temperature SEC. Future work using moment resolution procedures to derive an accurate calibration curve are also discussed.
Continuum Models for the Mechanical Response of Paper and Paper Composites: Past, Present, and Future
Authors: Suhling Jeffrey C. 
Published: March 2011

ABSTRACTPaper and paper composites are utilized in applications where they are subjected to multiaxial stress states and changing environmental conditions. Such materials exhibit nonlinear anisotropic material behavior which is time dependent and affected adversely by slight changes in moisture content and temperature. At present, lack of adequate theoretical models often hampers the design and development of structurally optimized paper products. Therefore, it has been common practice in the pulp and paper industry to use trial and error, and empirical approaches. Accurate continuum models for the mechanical behavior of paper and paper composites are needed to guide the paper product design process.In this work, a limited review of the existing methods for modeling the mechanical response of paper and paper composites is given. At first, a brief overview of the goals of current modeling techniques based on hydrogen bond, fiber network, and continuum approaches is presented. The governing equations and capabilities of current continuum models are then discussed in greater detail. Theories which include linear elastic (generalized Hooke's Law), nonlinear elastic (hyperelastic), linear viscoelastic, nonlinear viscoelastic, and inelastic constitutive relations are addressed. Finally, applications of existing continuum theories to the analysis of paper materials in structural configurations are presented. After these discussions, the limitations of the available continuum models are assessed and future research needs are suggested.
The Inter-Relationship Between Paper Structure and Print Quality in Ink Jet Printing
Authors: Oliver John F. , Jones A. Y. 
Published: March 2011

ABSTRACTThis article describes a print quality evaluation of laboratory designed ink jet papers prepared on a dynamic former. A comparison with various plain and coated papers serves to illustrate the potential opportunity for papermakers to exploit novel types of paper structures in the future. The article will also briefly focus on some of the fundamental issues and key paper properties which perturb print quality and govern the capillary absorption of aqueous inks.
Application of Surface Science Techniques to the Understanding of the Colloidal Properties of Papermaking Materials
Authors: Sanders Nicel D. , Schaefer John H. , Bashey Ali R. , McElroy Eric B. 
Published: March 2011

ABSTRACTSophisticated surface science techniques long familiar to materials researchers are now being used routinely to characterize the colloids found in papermaking systems. Ion Scattering Spectroscopy (ISS) is used to obtain the surface elemental composition of inorganic filler pigments. Laser light scattering is applied to the determination of particle size and particle charge distribution by way of the methods of Photon Correlation Spectroscopy (PCS) and Doppler Electrophoretic Light Scattering (DELS). The heats and races of interaction of hydrophilic colloids (water soluble polyelectrolytes) with hydrophobic colloids are determined by batch titration microcalorimetry.
Interfacial Aspects of Reinforcement of Wood by Mineral Fibers
Authors: Subramanian R.V. , Park J.M. 
Published: March 2011

ABSTRACTSignificant aspects of fiber reinforcement of wood are introduced. The effectiveness of three different silane coupling agents; one monomeric 3-aminopropyltrimethoxy silane, two polymeric aminosilanes (one dimethoxy- and another trimethoxy substituted), was compared by measurement of interfacial shear strength in silane treated single filament composite (SFC) specimens, under dry and wet conditions. The trimethoxypolymeric silane was found to be inferior to the other two, which warrant further investigation in strength tests with basalt fiber reinforced wood specimens. Acoustic emission measurement during the SFC tests has provided evidence for the sizing effect of polymeric silane coatings, as well as for moisture attack at severe surface flaws on the fiber during silane treatment.
Extruded Wood-Flour Polypropylene Composites: Effect of a Maleated Polypropylene Coupling Agent on Filler-Matrix Bonding and Properties
Authors: Myers George E. , Kolosick Paul C. , Chahyadi Ichwan S. , Coberly Camden A. , Koutsky James A. , Ermer Donald S. 
Published: March 2011

ABSTRACTFull factorial studies were conducted to determine the effects of a coupling agent (a low molecular weight maleated polypropylene (MAPP)) and other composition and processing variables on the mechanical properties of a wood-flour-filled polypropylene (PP) composite. Effects of MAPP on the bonding between PP and wood veneer were also examined. At less than 1 percent by weight, MAPP produced useful increases in strength and modulus properties of the composite, and this effect was somewhat enhanced by small-particle-size wood flour and multiple extrusions. However, MAPP caused small losses in notched impact energy. High extrusion temperature (190°C to 250°C) had little influence on strength, but it decreased notched impact energy. Peel force between PP and wood veneer was increased by pretreatment with MAPP for aspen, but not for birch, aspen being more porous than birch. The effectiveness of MAPP may therefore be related to its ability to penetrate the wood and form a strongly held hydrophobic layer that is attractive to the PP, thereby increasing both the effective bonding area and mechanical interlocking.
Tem Characterization of Dislocations in GaAs-ON-Si Heterostructures Wite Sjpereatlice Intermediate Iayers
Authors: Soga T. , Nishikawa H. , Jimbo T. , Umeno M. 
Published: March 2011

ABSTRACTGaAs was grown on Si substrate by metalorganic chemical vapor deposition using GaAs/GaAsP strained layer superlattice (SLS) intermediate layers. The dislocation density decreases at the interface between GaAs and SLS, but does not decrease in the SLS. When GaAs/GaAsP SLS is used as the intermediate layer, a part of the dislocation propagates into the top GaAs layer because of the lattice mismatch of GaAs and SLS. The low etch-pit-density of (3-5) x 105 cm−2 was obtained by using the intermediate layer of GaAs/GaAsP SLS and AlAs/GaAs superlattice with thermal-cycle annealing.
InGaAs/GaAs Graded Superlattices in Photodetectors for Wavelengths Beyond 1 μm
Authors: Mariella R. , Morse J. , Liliental-Weber Z. 
Published: March 2011

ABSTRACTWe have used MBE to grow graded InxGa1−xAs/GaAs superlattices on GaAs substrates as buffers for larger period, constant composition InxGa1−xAs/GaAs superlattices. TEM analysis shows that there are numerous crystal defects associated with the presence of strained layers, but, in many cases, the buffer layers confine these defects to areas outside of the strained-layer superlattices. PIN detectors fabricated from these structures show external quantum efficiencies up to 2.7 %.
Electron Microscopy and Diffraction of the Early Stages of Metal Heteroepitaxy
Authors: Bauer E. 
Published: March 2011

ABSTRACTThe application of some characterization methods to the study of heteroepitaxy is illustrated by recent work in the authors laboratory on the epitaxy of Cu on Mo and W(110). In particular, the use of PEEM and LEEM in the study of the epitaxy of Cu, Au and Co on Si(111) is discussed.
Computer Simulation of the Metal Organic Chemical Vapor Deposition of CdTe
Authors: Kang S. , Jasinski T.J. , Tompa G.S. , Stall R.A. 
Published: March 2011

ABSTRACTThe optimization of chemical vapor deposition processes requires an understanding of the influence of various process parameters on the deposition of thin films. A recently developed computer simulation tool provides a powerful means to develop this understanding. This paper describes the use of the computer program, FLUENT, to study the gas flow, temperature, and chemical species distributions during the deposition of CdTe. Numerical results are reported for two operating conditions for an EMCORE vertical high-speed rotating disk growth reactor and are compared to experimental data. The influence of process parameters is discussed. The effects of the addition of significant amounts of Hg (several percent) to the process gas is evaluated.
Role of Si1−xGex Buffer Layer in Determining Electrical Characteristics of Modulation-Doped p-Si0. 5Ge0.5/Ge/Si1−xGex Heterostructures
Authors: Murakami Eiichi , Etoh Hiroyuki , Nishida Akio , Nakagawa Kiyokazu , Miyao Masanobu 
Published: March 2011

ABSTRACTElectrical characteristics of modulation-doped p-Si0.5Ge0.5/Ge/Si1−x Gex heterostructures are examined in relation to Si fraction (1−X) and thickness (dB)of the buffer layer (Si1−xGex), using Raman spectroscopy and transmission electron microscopy. Strain-induced enhancement of hole mobility and concentration is observed in 1-X≦0.25. However, their decrease in 1-X≦0.25 and for small dB values is also observed, which is attributed to the increase in threading dislocations. As a result, a maximum hole mobility of 7600 cm2/Vs at 77 K is obtained at 1-X=0.25 and dB=1μm.
Defect Reduction of Cvd-Grown Cubic SiC Epitaxial Films on Off-Axis Si(100) Substrates with a Novel Off-Direction.
Authors: Furukawa Katsuki , Fujii Yoshihisa , Suzuki Akira , Nakajima Shigeo 
Published: March 2011

ABSTRACTMonocrystalline cubic SiC (β -SiC) thin films with lower defect densities have been epitaxially grown by chemical vapor deposition on off-axis Si (100) substrates with off-directions different from the conventional 〈011〉. Stacking faults of β -SiC films are investigated by the electrolytic etching and SEM observation. The effects of off-direction deviated from 〈011〉 are examined for the first time. The off-angle is fixed at 2 degrees. We find a reduction in defect density with increasing deviation angle θ, of off-direction from [011] toward [011[ (θ = 0 - 45°). The defect density becomes one order of magnitude smaller than that of on-axis (100) substrates. A typical value of the stacking fault density is approximately 6 × 106 cm−2 on the substrate with θ = 30° (film thickness: 24μ m).
Elecitrical Properties of Ion Beam Sputtering Grown Epitaxial Yttria Stabilized Zirconia FIlms on Silicon
Authors: Hesto P. , Pellet C. , Schwebel C. , Dupont-Nivet E. , Noxaic A.Le 
Published: March 2011

ABSTRACTYttria stabilized zirconia (YSZ) films have been characterized. The refractive index measured by ellipsometry is about 2.1. The breakdown electric field is greater than 4MV/cm for small area capacitors with a decrease for large area capacitors. This dielectric strength is weakly dependent on the film thickness within the range 0.2-1.lμm. The analysis of the 1MHz C(V) curves by the Terman method leads to a density of interface states of the order of 1012cm−2eV−1 in the middle of the bandgap with an increase near the conduction and the valence bands. The sensitivity of zirconia to the irradiations has been characterized by analysing 1MHz C(V). With or without electric field applied during the irradiations, the Flat-Band voltage shifts are lower for YSZ films than for thermal silicon dioxide films (2 times smaller).
Formation of Pinhole-Free Epitaxial Yttrium Silicide on Silicon(111)
Authors: Siegal Michael P. , Santiago Jorge J. , Graham William R. 
Published: March 2011

ABSTRACTWe report the growth of structurally continuous, pinhole-free epitaxial YSi2−xfilms on Si(l1l) substrates as thin as 30Å. This is accomplished by depositing both yttrium andsiicon in the appropriate stoichiometric ratio onto substrates held near room temperature, which is apparently below the activation energy for the nucleation of a reaction between a deposited Y film and a Si substrate. Diffusion of Si atoms from an evaporation source into a thin Y layer occurs below this barrier energy, allowing the layer by layer formation of YSi2−x without the removal of silicon from the substrate, maintaining a relatively low interface free energy between the growing silicide film and the Si(lll) substrate. Samples have been annealed to 500-900°C to improve epitaxy without the creation of pinholes. Use of the template method allows for the growth of thicker films also free of pinholes.
Temperature Dependence of Compositional Disordering of Gaas-Alas Superlattices During Mev Kr Irradiation
Authors: Bryan R. P. , Miller L. M. , Cockerill T. M. , Coleman J. J. , Klatt J. L. , Averback R. S. 
Published: March 2011

ABSTRACTThe influence of the specimen temperature during MeV Kr irradiation on the extent of compositional disordering in GaAs-AlAs superlattices (SLs) has been determined. We have investigated whether radiation-enhanced diffusion (RED) could be employed to reduce the dose required to completely disorder a SL by ion implanation. Metalorganic chemical vapor deposition grown GaAs-AlAs SLs were implanted with 0.75 MeV Kr to a dose of 2×1016 cm−2 at various sample temperatures ranging from 133 K to 523 K. The extent of disordering induced by the irradiations was determined by Rutherford backscattering spectrometry and secondary ion mass spectrometry. For low temperature irradiations (133 K to 233 K), complete intermixing of the SL is observed. However, the extent of intermixing of the SL decreases with increasing specimen temperature between room temperature and 523 K. We propose two possible explanations to interpret these results: (i) that the amount of ion beam mixing decreases with increasing temperature; and (ii) that the RED coefficient is negative which suggests the existence of a miscibility gap in the GaAs-AlAs SL system.
A Use of Specimens in Form of Tips for In-Situ Experiments in Electron Microscopes (Preparations, Preliminary Results)
Authors: Drechsler M. 
Published: March 2011

ABSTRACTA long term aim of this study is to overcome the difficulties to use electron microscopes (TEM, SEM) for in situ experiments, which includes (1) a preparation of initially clean surfaces, (2) a use of specimen micro-chambers, (3) in situ heating, (4) devices to produce and analyse reactions and (5) video registration. An interesting step in this direction is the replacement of the usual thin films by specimens in form of tips similar to those used in field emission devices. A tip is first prepared by electrolytic etching. Then the tip is cleaned and shaped in vacuum. This opens the possibility to visualize and measure kinetic phenomena up to higher temperatures than so far (1500 K and more). Examples of results are: (1) Surface matter fluxes and surface self-diffusion can be measured, (2) solid/solid interfaces and their displacements (reactions) can be measured, (3) grain boundary displacements and grain rotations can be measured and (4) periodic electric discharges between electrodes of 0.1 gim on specimens are prepared, visualized and explained.
The Preparation of Fine Particulate for Electron Microscopy Investigations Using Dental Amalgam
Authors: Chumbley L. S. , Laabs F. C. , Sanders S. C. 
Published: March 2011

ABSTRACTSamples of high Tc superconductors and metal powders have been prepared for Scanning and Transmission Electron Microscopy examination by a novel method. Dental amalgam, commonly used for filling cavities in teeth by dentists, has been used as a binding agent to hold the sample particulate together during sample preparation. The amalgam was pressed into a small rod 3 mmn in diameter and samples were prepared by cutting slices from the rod followed by mechanical grinding and ion milling to perforation. This technique is extremely easy and offers several advantages over other preparation methods. Experiments revealed difficulties due to preferential sputtering yield, but generally these could be overcome and good thermal and electrical properties of the amalgam partially offset the former inconveniences. It should be possible to use this technique for any number of materials, including ceramic materials and small non-spherical particulate.
Problems and Artifacts on Extraction Replicas of Membrane Filters
Authors: Turner S. , Steel E. B. , Landis E. S. 
Published: March 2011

ABSTRACTFor studies of particles suspended in air or water, material is commonly deposited onto membrane filters. Submicrometer particles collected in or on the surface of the filters can be prepared for analysis by TEM by extraction replica methods. To identify the problems and artifacts generated during the preparation process, evaluations were made of replicas prepared internally at NIST and prepared by laboratories involved in the analysis of air-collected asbestos. Problems or artifacts that could affect the counting and analysis of asbestos particles were identified and characterized. Results of evaluations of replicas prepared by eighteen laboratories in an interlaboratory study are summarized.
A Fast and Precise Specimen Preparation Technique for TEM Investigation of Prespecified Areas of Semiconductor Devices
Authors: Romano Albert , Vanhellemont Jan , Bender Hugo 
Published: March 2011

ABSTRACTIn this paper we present a rapid and highly precise plan view and cross-section specimen preparation technique for the localized thinning of semiconductor devices for TEM investigation. No special equipment except the commercially available one is required. Crosssection preparation takes about 6 hours, while plan view takes about 4 hours. Prespecified areas of 0.6 μm wide and 10 μm long can easily be thinned with transparency for CTEM and HREM. Using an iterative ion milling procedure allows to scan a complete device in HREM.
Preparation of Cross Sectional and Plan View TEM Samples of Thin Films on Mgo Substrates with an Additional Chemical Thinning Step
Authors: Rou Shang. H. , Hren Philip. D. , Kingon Angus. I. 
Published: March 2011

ABSTRACTSingle crystal MgO is a common substrate for the deposition of oxide thin films. The conventional cross sectional transmission electron microscopy sample preparation procedure suffers the drawbacks of: 1)- extensive ion milling time; 2) a higher milling rate for the thin films than for the substrate; 3) introduction of artifacts and contamination during ion milling; and 4) generation of excess defects into the substrate during mechanical thinning. An additional chemical thinning step using hot orthophosphoric acid can reduce or eliminate these adverse effects.This technique can be applied generally to thin film samples deposited on substrates with a low ion milling rate. Furthermore, substrates which are sensitive to mechanical stress and ion beam damage are also suitable for this technique, provided an appropriate chemical polishing solution and compatible epoxy can be found. The unique features of this technique are briefly presented.
A Technique for the Preparation of Thin-Film Cross-Sections for Transmission Electron Microscopy
Authors: Libera M. , Nguyen T. A. , Hwang C. 
Published: March 2011

ABSTRACTA number of techniques for producing TEM cross-sections of thin films have been described in recent years as the need for improved and more-thorough microstructural study of thin-film materials has grown. We have developed a method for producing such cross-sections which involves little sophisticated equipment other than an ion mill for thinning. Following the method of Bravman and Sinclair (J. Elec. Micrs. Tech 1,53–61 (1984)), the film of interest is either deposited on or epoxied to a silicon wafer and a composite of six silicon beams (=3mm × 25mm × 0.5mm) is fabricated. Slices are cut from this composite perpendicular to the film plane, and each slice is mechanically thinned by a series of simple grinding and polishing steps to ∼ 50–100μm. Dimpling is not necessary. The specimen is mounted onto a slotted TEM grid which provides a vehicle for safe handling, and the specimen is ion milled to perforation. We have found the technique to be relatively fast, reliable, and simple. Its success hinges on minimizing the amount of direct handling required when the specimen is thin and fragile. We present a detailed recipe describing its various steps and show typical results from studies of thin films for data-storage applications.