bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Multiplication Mechanism for Misfit Dislocations
Authors: Capano Michael A. 
Published: March 2011

ABSTRACTA new mechanism which describes how misfit dislocations in epitaxial layers multiply is presented. This work demonstrates how a single threading dislocation can give rise to an array of dislocation sources, where each source generates a single dislocation loop perpendicular to the primary misfit dislocation. As a threading dislocation with pure screw character glides through an epilayer, certain processes occur which lead to the production of a single dislocation half-loop, and the regeneration of the original threading dislocation. The regenerated threading dislocation continues to propagate on its primary glide plane, which allows the process to repeat itself at some later time. The result of this sequential process is an array of half-loops perpendicular to the primary misfit dislocation. The shape and symmetry of the arrays also contains information regarding how the mechanism operates. The proposed mechanism is related to misfit dislocation arrays in a single Si0.87Ge0.13 layer on Si(001).
Initial Stages of Growth of Epitaxial InAs Films on InP Substrate
Authors: Sekhar K. S. Chandra , Ballal A. K. , Salamanca-Riba L. , Partin D. L. 
Published: March 2011

ABSTRACTIn this work we investigate the initial stages of growth of heteroepitaxial films of InAs on semi-insulating InP substrates using MOCVD. Very thin films grown at different temperatures, Tn, were studied using TEM and SEM. The 3.2% lattice mismatch between InAs and InP causes strains that are partially accomodated by the generation of misfit dislocations at the interface. Our studies indicate that the deposited InAs nucleates in the form of islands which then grow and coalesce to form the film. Elemental mapping studies indicate that the area of substrate covered by the film is a function of the growth temperature. The thickness of the film and the electron mobilities also vary with T°. The films with best mobilities were obtained for Tn = 480°C.
Step-Driven Surface Segregation and Ordering During Si-Ge MBE Growth
Authors: Jesson D. E. , Pennycook S. J. , Baribeau J.-M. , Houghton D. C. 
Published: March 2011

ABSTRACTAn important role of type SB step edges in determining the as-grown microstructure of Si-Ge superlattices and alloys is implicated from direct Z-contrast images of as-grown structures. A variety of different ordered phase variants can arise at each Si on Ge interface as a result of vertical segregation during superlattice growth. A new monoclinic-ordered structure is predicted to arise as a result of lateral segregation during alloy growth.
New Developments in Soluble Thermoplastic High Glass Transition Temperature Polyimides
Authors: Rogers M. E. , Moy T. M. , Kim Y. J. , McGrath J. E. 
Published: March 2011

AbstractUtilizing solution imidization, molecular weight and end group control techniques, soluble, fully cyclized polyimides with very high glass transition temperatures have been developed to meet high temperature applications. Mechanistic aspects are investigated for solution imidization by both the polyamic acid route and by the ester-acid route. Polyimides based on pyromellitic dianhydride and a 3F diamine exhibit glass transition temperatures of 420 °C. These polyimides are soluble in polar aprotic solvents and form tough, transparent films which demonstrate mechanical integrity and thermooxidative stability at 700 °F. Various processing routes are explored to demonstrate the viability of these materials in high temperature applications. Details of the synthesis and characterization of these materials will be provided.
Mechanical Characterization and Constitutive Description of Thin-Film Polymeric Materials
Authors: Wu T. Y. , Questad D. L. 
Published: March 2011

AbstractMechanical properties of thin-film polymers often dictate the mechanical integrity and performance of microelectronic assemblies. For example, excessive interfacial stress between the polymer and signal via induced by thermal mismatch will lead to delamination of the interface or via cracking. This type of problem becomes more aggravated as dimensions of assemblies continue to shrink. In order to define the optimal design variables and process windows, the mechanical properties of polymer thin films throughout the complete process cycle must be carefully characterized. This paper will first review the experimental techniques commonly adopted in the mechanical measurements of thin-film polymers. Then, it will focus on the most difficult part of the mechanical characterization which is along the out-of-plane (Z) direction. Experimental set-up using the capacitance gauge will be introduced. Critical mechanical properties of polymers will be discussed. For the purpose of illustration, two polymers are chosen as examples. A BPDA-PDA polyimide is used to demonstrate mechanical characterization before melting whereas a PTFE-SiO2 composite is chosen to demonstrate the rheological characterization after melting. Before melting, mechanical behaviors such as the stress-strain curve, creep, relaxation, coefficient of thermal expansion, strain-rate dependence, and temperature dependence are discussed. After melting, the rheological behavior and the effect of aspect ratio measured by a squeezing flow experiment are addressed. Constitutive descriptions are proposed. The functional dependency between stress (pressure), strain (displacement), time, and temperature are characterized. A comparison between the numerical simulations and the experimental measurements is also presented.
Studies of PQ-100(TM) Polyquinoline Film for Multichip Module(MCM) Applications
Authors: Paik Kyung W. , Cole Herbert S. , Hendricks Neil H. 
Published: March 2011

AbstractOxygen and O2+CF4 RIE showed faster etch rate of PQ-100 film than nonoxygen containing RIE, and caused rough surface morphology. Ti shows good adhesion to the PQ-100 film because of Ti-O and possible Ti-N compound formation at the interface. No diffusion of Ti and Ti-containing precipitates were observed at the Ti/PQ interface even at temperatures of 250 °C. In contrast to the Ti/PQ interface, Cu showed very poor adhesion to the PQ film because of weak chemical bonding. Cu reaction compounds were not observed at the interface at the 250 °C annealing. Ti adhesion to the PQ-100 film was good for control, RIE modified, and water-boiled cases. Initial studies suggest a reduction in peel strength at 250 °C annealing, although this topic must be further addressed to understand the exact mechanism.
The Adhesion of Polymer-Polymer Interfaces
Authors: Brown Hugh R. 
Published: March 2011

AbstractThe adhesion of glassy or semicrystalline polymers to themselves or to other polymers is often poor. Polymers gain their strength from the mechanical interconnection between different chains. This interconnection can occur either by the use of long chains that entangle with each other or by chemically joining the chains by cross-linking. A strong polymer-polymer interface is crossed by many chains that are mechanically coupled into the material on both sides of the interface. For cross-linked systems these coupling chains must be cross-linked into both sides. If the polymers are not crosslinked, the coupling chains are formed by interdiffusion or welding. Interdiffusion can occur only if the system is heated to a temperature that allows significant chain mobility and if the interconnecting chains are sufficiently miscible in both polymers. For some systems, such as polyimides, the mobility required can either be generated by just part curing the materials before joining or by reversing the completed cure of a thin surface layer before joining and completing the cure. The interconnecting chains do not have to be the same material as the polymers being joined and, for joining dissimilar polymers, can be block copolymers where each block is miscible in just one of the relevant polymers.
Experimental Analysis of the Adhesion of Copper and Chromium Films Deposited on a Polymer
Authors: Ignat M. , Fayette L. , Normandon P. , Templier F. , Torres J. 
Published: March 2011

AbstractAn analysis of bulk and interfacial damage of film/substrate systems consisting of copper or chromium films deposited on a single polymer substrate, is presented here. For these systems (metal/single polymer substrate) the failure analysis is based on the experimental results obtained from deformation experiments performed in a scanning electron microscope. Critical parameters deduced from the experiments, and microstructural observations allow us to discuss the mechanical behaviour of these systems, and their interfacial adhesion properties.
A New Gold-Indium Eutectic Bonding Method
Authors: Lee Chin C. , Wang Chen Y. , Matijasevic Goran , Chan Steve S. 
Published: March 2011

AbstractAu-In eutectic bonding method which needs only a low process temperature (˜200°C) but produces high temperature (450°C) bonds is reported. In this study, multiple layers of Au and In are deposited directly on semiconductor wafers in one vacuum cycle to prevent indium oxidation and then bonded to substrates coated with Au. At 200°C the indium layer melts and dissolves the gold layers to form a mixture of liquid and solid. The diffusion process continues until the bond solidifies. Upon solidification, the bond has a melting temperature of 456.5°C. Scanning Acoustic Microscope was used to determine the excellent bonding quality before and after thermal shock tests and SEM with EDX capability is employed to determine the composition of the resulting bonds.
Optical Interconnects and Interfaces for Electronic Subsystems
Authors: Rajasekharan K. , Krusius J.P. , Sutherland J. , George G. 
Published: March 2011

AbstractThe potential, feasibility, and time scale of optical interconnect and interfaces are examined for electronic computer applications. Link, bus and random interconnect topologies are included. Recent developments in optical source and detector devices, optical waveguides and optical fiber characteristics are reviewed. Then optical coupling, alignment, interfacing and overall compatibility issues are explored. From this understanding the requirements for the packaging of optical interconnect are derived. Finally key research and development needs are defined.
Polymer/Metal Interconnection Systems for Microelectronics Packaging
Authors: Tong Ho-Ming 
Published: March 2011

AbstractThis article provides an overview on polymer/metal interconnection systems for microelectronics packaging. It will begin with a description of the functions of interconnection, and types of polymer/metal interconnection techniques available with tape automated bonding (TAB) being the most popular for chip connection applications. This is followed by examples of worldwide TAB applications and market outlook, TAB tape offerings and trends, as well as the entire TAB technology including tape types and fabrication, substrates interconnected by TAB, bonding techniques, TAB mounting options and TAB package encapsulation. Finally, future challenges on the most demanding fine-pitch TAB technology will be discussed.
Polyimide for Multichip Modules: Materials and Process Challenges
Authors: Rucker T. , Murali V. , Shukla R. , Neuhaus H. 
Published: March 2011

Abstract:As the performance of desk-top systems approaches 100 Mhz there is a need to develop a packaging technology capable of supporting high speed chip to chip interconnections. Polyimide based multichip modules are excellent packaging solutions that have minimum propagation delays and are cost effective. This paper presents the material properties and processing issues that need to be addressed in building reliable modules. A cost effective and reliable packaging solution is described in detail.
Recycling of Wood and Paper in Cementitious Materials
Authors: Soroushian Parviz , Arola Rodger A. , Shah Zahir 
Published: March 2011

AbstractBeneficial utilization of wastepaper and wood in cement-based materials is reviewed. Wastepaper presents a source of reinforcing fibers for thin-sheet cement products; these fibers help overcome the problems with the brittle nature of failure and low cracking resistance of plain cement products. Wood waste and sawdust can be used in concrete as light-weight aggregates capable of enhancing the weight-to-strength ratio, insulation properties and toughness characteristics of concrete materials.
The Basic Effects of Recycling on Pulp Properties
Authors: Howard R. C. , Bichard W. 
Published: March 2011

AbstractUsing standard laboratory procedures it was found that different pulp types showed very different recycling effects. Mechanical pulp fibres became flatter and more flexible giving a denser, stronger sheet. Beaten chemical pulp fibres “hornified”, resulting in a bulkier, weaker sheet. Unbeaten chemical pulp fibres were initially curly; recycling removed the curl. A mechanical/chemical pulp blend revealed that these effects occur at different rates. In no case was there evidence of fibre strength loss, or of fibre embrittlement. In these laboratory experiments, fines loss during sheetmaking affected the magnitude of the sheet properties, but not the trends.
Recycled Structural Papers: New Approaches for Material Property Improvement
Authors: Laufenberg Theodore L. , Hunt John F. 
Published: March 2011

AbstractRecycling of fiber into structural papers for the corrugated container industry, paper tubes, cartonboard or other paperboard with structural performance needs may require enhancement of properties through changes in the papermaking process. The loss of bonding capability, coupled with a degree of fiber shortening and fiber inflexibility, reduces the utility of recycled fiber and thus their competitiveness with their virgin counterparts. Traditional means for enhancing performance includes addition of starches or other binders, mechanical beating, or heat treatments. Other means for achieving heightened performances are reviewed which include alternative drying technologies, optimal placement of fibers within the paper sheet and forming technologies that provide structural enhancement. KEYWORDS: Fibers. fractionation, swelling, drying methods, fiber bonding. fiber alignment, pulp molding.
Opportunities for Composites from Recycled Wood Based Resources
Authors: Wegner Theodore H. , Youngquist John A. , Rowell Roger M. 
Published: March 2011

AbstractA reduction is urgently needed in the quantities of industrial and municipal solid waste materials that are currently being landfilled. Major components of municipal solid waste include waste wood, paper, agriculture wastes, and other biomass fibers. In 1990, there were approximately 80 million tons of 6,000 different paper and paperboard products and 5.8 million tons of wood in the municipal solid waste stream. There are also potential millions of tons of wood fiber in timber thinnings, industrial wood waste, demolition waste, pallets, and pulp mill sludges. These materials offer great opportunities as recycled ingredients in wood-based composites. This paper discusses possibilities for manufacturing selected composites from these materials as well as materials which coexist with the wood-based resources such as plastics, fly ash, and gypsum.
Fiber Based Composites from Recycled Mixed Paper and Magazine Stock
Authors: Rowell Roger M. , Harrison Sandra 
Published: March 2011

AbstractFor most products, processing recycled paper back into paper will require de-inking and removal of coatings and fillers. Paper to paper recycling will also require sorting the paper waste stream to insure that the stock used contains the type of fiber needed. These problems can be eliminated if the waste paper product stream is used to make fiber based composites. Mixed office waste, packaging materials, paperboard, newspaper, and many other types of paper fiber can be used directly for the production of thermosetting or thermoplastic fiber based composites. High levels of clay used in magazine paper can be tolerated in these composites. This paper will review research in making fiber based composites from several waste paper streams and the properties of these products.
Sulfate Formation During Corrosion of Copper Alloy Objects
Authors: McNeil Michael B. , Mohr D. W. 
Published: March 2011

ABSTRACTThe copper sulfate minerals chalcanthite (CuSO4.5H20), antlerite (Cu3SO4(OH)4), and brochantite (Cu4SO4(OH)6) are observed as corrosion products on copper alloy objects such as statues which are exposed to weathering. The usual product in aqueous corrosion is brochantite, though posnjakite (Cu4SO4(OH)6H20) is also known. No copper sulfate mineral is commonly found in artifacts recovered from near-surface burial. These observations can be explained in terms of stability diagrams and microbiological activity.
Evaluation of Rapid Prototyping Technologies for Use in the Production of Art and Artifact Study Copies
Authors: Podany Jerry C. 
Published: March 2011

ABSTRACTMany artifacts and works of art are too fragile to be accurately replicated for scholarly study by using traditional methods of plaster or silicone molding techniques. In addition to the potential for loss of surface and fracturing, the use of many modern silicone mold materials may lead to irreversible staining of the original surface.An evaluation of newly developed rapid prototyping technologies and their potential application to this problem was conducted by the J. Paul Getty Museum Department of Antiquities Conservation in conjunction with Laser Design Inc. of Minnesota and Hughes Aircraft Corp. of California.Rapid prototyping technology allows accurate copies to be made without surface contact with the original object. This paper discusses the outcome of an initial investigation into one of these processes, stereolithography. A plaster model was submitted for laser scanning using a point laser probe, programmed for a 3.175 mm (0.125) distance between scan lines. The input was filtered and stored in an STL (stereolithography) format which provides the X,Y and Z coordinates of the A,B,C and normal vectors of a predetermined number of surface triangles. This data was then used to produce a three-dimensional copy.Stereolithography produces hollow or solid threedimensional forms by feeding data that make up cross sectional slices of the object scanned to a focused laser aimed along the Z axis of the potential copy. The laser polymerizes the outer contour of the 'slice' in a thin layer of photopolymer deposited on a stage located below the laser. Following each slice production the stage lowers approximately 19 mm (0.75) below the surface of the liquid polymer reservoir and upon resurfacing positions approx 0.05mm (0.002) lower than its previous position. A “squeegee” gently crosses over the surface resulting in a thin film of polymer available for the production of the next cross section. The laser is then sent the next cross sectional data and the sequence of section building continues.The specific challenge presented by this project was to assure that the surface detail of the copy formed presented acceptable fidelity to the original object (model), avoiding any need for follow up bench work or correction. The advantages, drawbacks and newly developed alternatives to this promising technology are discussed.
Monuments as Targets
Authors: Koscevic Zelimir 
Published: March 2011

ABSTRACTMy paper is a video presentation, but before I show it, allow me just a few words. My contribution is not a scientific paper. In this video we shall be faced with the facts. Facts are always that starting point in the process of thinking, and thought is the basis of human activity. These facts are given concisely in 25 minutes, which is — frankly — nothing compared to the hours and hours I spent watching the raw documentary material, selecting it, and making the final version of the video that you are about to see.
Saving Grace: Can Cambodia's Ancient Site of Angkor be Preserved?
Authors: Garfield Donald 
Published: March 2011

ABSTRACTFor 1,200 years Cambodia's historic royal complex of Angkor, one of the world's architectural wonders, has survived all threats from man and nature. But the greatest pressures on Angkor have come during the late 20th century, especially the devastation caused by more than two decades of war and civil strife. Now, with increased conservation and restoration efforts initiated by the World Monuments Fund and other international cultural institutions and coordinated by the United Nations Educational, Scientific and Cultural Organization (Unesco), three new threats have emerged. One is an increase in the looting of the sculptures and bas-reliefs decorating the sides of temples, galleries, and terraces. The second is the lack of a comprehensive, coordinated plan for conservation. The third, with potentially the most destructive results, is the uncontrolled development of the sacred site as a major tourist attraction.
Analysis of Materials Contained in Mid-4th to Early 7th Century A. D. Palestinian Kohl Tubes
Authors: Blanchard William D. , Stern E. Marianne , Stodulski Leon P. 
Published: March 2011

ABSTRACTThe powdered contents of 17 Late Roman and Byzantine glass vessels used to hold cosmetic eye-paints (kohl) were analyzed. The principal analytical techniques employed were X-ray diffraction, Fourier-transform infrared spectrometry, X-ray fluorescence, and scanning electron microscopy. The materials detected are described, indicating those which may have been used as kohl. Also reported are analytical results from a solid chunk of material surrounding a fragment of a metal rod, also obtained from a kohl vessel.
Examination of Metal Threads From Some Xv/Xvi Century Italian Textiles by Scanning Electron Microscopy-Energy Dispersive X-Ray Spectrometry
Authors: Montegut D. , Adelson C. , Koestler R.J. , Indictor N. 
Published: March 2011

ABSTRACTScanning electron microscopy and energy dispersive x-ray spectrometry (SEM-EDS) has been employed along with the light microscope to describe some metal threads taken from some late Medieval and Renaissance textiles attributed to Italy in the collection of the Metropolitan Museum of Art, New York. Comparisons are made within the group studied and to those descriptions of metal threads found in recent literature. The results are discussed in terms of geographic and historic markers of the metal thread technology employed.
Neutron Induced Autoradiography and Pixe Analysis
Authors: Taft W. Stanley , Mayer James W. , Aderhold Howard C. , Keller Matt , Rizzo Gia 
Published: March 2011

ABSTRACTWe have used the TRIGA reactor and the Ion Beam Facility at Cornell to illustrate neutron induced autoradiography and PIXE analysis of known pigments in demonstration paintings made for our undergraduate course, ‘Art, Isotopes and Analysis’. A group of pigments were chosen containing elements with half-lives detectable by the neutron activation process. The pigments (suspended in a binding medium of linseed oil) were first painted on test swatches of acetate and their characteristic x-ray lines measured with a 5 Mev beam of protons directed through a thin Kapton film for external (in air) analysis (PIXE).Three layers of images, each painted with a different pigment, overlay one another. The painting is then taken to the TRIGA reactor for neutron activation. After activation, the painting is placed in contact with sheets of Polaroid type AR positive transparency film at different times after exposure. The gamma spectra during the sequence are also measured to provide identification of the ‘active’ isotopes during each film exposure.