bluuebunny/crossref_metadata_2025_split huggingface dataset:
Model for Far Field Migration
Authors: Rasmuson Anders , Neretnieks Ivars 
Published: March 2011

ABSTRACTA transport model of radionuclide migration in fissured rock is presented. It includes advection and hydrodynamic dispersion in the fissures and diffusion and sorption in the rock blocks. 1 and 2D analytical and 3D numerical solutions of the model have been developed. A large number of calculations for the approximate range of variation of the input parameters have been performed. A large impact of hydrodynamic dispersion and micropore diffusion on the amount of radioactive material reaching the biosphere is found.
Linear Zone-Melt Recrystallized Si Films Using Incoherent Light
Authors: Kamgar Avid , Rozgonyi G. A. , Knoell R. 
Published: March 2011

ABSTRACTIncoherent tungsten radiation has been used to recrystallize polysilicon films deposited on SiO2, grown on 75 mm diameter wafers. These films have been analyzed by a variety of techniques such as optical microscopy, Auger spectroscopy and TEM crosssectioning. These films are large (> 50 mm dia.) single crystals, and contain fewer defects and impurities than similar films recrystallized in graphite strip heater ovens. They do, however, contain the subgrain boundaries found previously, even when high purity Mbe polysilicon is used. In vertical tem cross-sectioning, in addition to the subgrain boundaries,we have seen crystallized particles of 50200 Å size in the si film at both the upper and lower SiO 2 boundaries. Although these particles could be relatedto formation of the subgrain boundaries, no definite correlation has been made.
Waste Glass/Repository Interactions
Authors: Clark D.E. , Maurer C.A. 
Published: March 2011

ABSTRACTThe effects of repository material and a tailored backfill or overpack on the leaching behavior of glass have been studied. Two types of glasses were used in this investigation: 1) Model glasses comprised of 33 mol% alkali oxide-67 mol% SiO2 , and 2) alkali borosilicate glasses with and without simulated wastes. Several types of repository material were placed in the same containers as the glasses to determine if their presence would alter the extent of leaching. A backfill material consisting of phosphate slime/sand mixtures was evaluated with the same procedure. The results indicate that the leaching behavior of the glass may be influenced by the presence of some materials. Preliminary results of a 16½ month burial experiment in Florida are also discussed.
Laboratory Tests on the Migration Behaviour of Selected Fission Products in Aquifer Materials from a Potential Disposal Site in Northern Germany
Authors: Behrens H. , Klotz D. , Lang H. , Moser H. , Barke G. , Bruhl H. , Gehler S. , Muhlenweg U. 
Published: March 2011

ABSTRACTThe migration behaviour with respect to retardation by sorption of radioactive Ce, Cs, I, Nb, Ru, Sm, Sr, Tc and Zr in fluviatile and aeolian sand aquifers has been examined in laboratory tests. In these tests it was attempted to simulate the natural conditions of the field. The tests were performed as batch and column experiments. The results of both types of experimental procedures agree within the error limits and show- small sorption for I− and TcO4−- medium sorption for Sr2+- high sorption for Cs+, Ce3+, Sm3+, Ru4+, Zr4+ and Nb5+The investigations will be continued with other geologic materials from the same site.
High-Temperature Dielectric Properties of Polycrystalline Ceramics
Authors: Ho W. W. 
Published: March 2011

ABSTRACTExperimental methods for determining the high-temperature millimeter-wave dielectric properties of solids are described and the data obtained on a wide variety of polycrystalline ceramics are reviewed. In general, the observed increase in dielectric constants with temperature can be modeled with a macroscopic dielectric virial expansion and shown to be primarily caused by an increase in polarizability due to volume expansion. The room-temperature loss tangents in low-absorption ceramics are probably caused by impurity doping of the primary and secondary crystalline phases at grain junctions and along grain boundaries. The rapid increase in loss tangent at high temperatures commonly observed in polycrystalline ceramics is associated with softening of intergranular amorphous phases resulting in an increase in localized electrical conductivity.
Measurement of the Absorption of Microwave Power by Corroded Metals
Authors: Bruce Ralph W. , Quar R. A. 
Published: March 2011

ABSTRACTMetal alloys, when exposed to a salt/organic environment at elevated temperatures, corrode resulting in a decrease in the surface conductivity. This decrease can be monitored and assessed via the measurement of the incident and reflected microwave signals impinging upon the corroded surface. Several metallic alloys, stainless steels and inconels, were treated with a salt/organic mixture (proprietary) and heat treated at 1100 F. Periodically, the metals were removed from the furnace, allowed to cool to room temperature, and measured electrically. The samples were re-coated with the salt/organic mixture and re-heat treated. The electrical measurements showed a generally increased power absorption as corrosion thickness increased.
Microwave Sintering of Ceramics Under High Gas Pressure
Authors: Tian Yong-Lai , Brodwin Morris E. , Dewan Hardial S. , Johnson D. Lynn 
Published: March 2011

ABSTRACTDuring microwave sintering of ceramics, the input microwave power and specimen temperature are limited by the breakdown of the gas in the cavity. The ionization potential of the gas, the temperature, and the specimen shape are all factors that influence the onset of breakdown. Thus, in the sintering of SiC rods in a TE111 cylindrical cavity at 1 atm argon or nitrogen, breakdown occurred at temperatures less than 1300 C and 1700 C, respectively, which are well below the required sintering temperature.Breakdown can be suppressed by applying either high vacuum or high pressure. Sintering in high vacuum would exacerbate the problems of decomposition and vaporization of ceramics such as Si3N4 and SiC at high temperatures. Pressurization not only suppresses breakdown but inhibits decomposition and vaporization.The TE111 cylindrical cavity has been adapted for pressurization to 1.38 MPa. The allowable input microwave power and specimen temperature have been markedly increased under high pressure conditions.
Microwave Processing at Ontario Hydro Research Division
Authors: Oda S. J. , Balbaa I. S. 
Published: March 2011

ABSTRACTOntario Hydro has established a Process Applications Laboratory dedicated to helping industry apply electrotechnologies for a variety of processes. Demonstration and development of industrial microwave applications are being conducted to provide an important interface between the industrial user and microwave equipment manufacturer. Curing, heating, tempering, sintering, calcining and drying are among the operations that have been successfully demonstrated on a wide range of products including polymers, ceramics, composites, paper and wood products, food, pharmaceuticals and textiles. The benefits of microwave heating are illustrated with examples of feasibility studies performed for manufacturers and a R&D project being conducted in-house.
Structural Adhesive Curing for Bonding Composites, Thermosets and Thermoplastics
Authors: Rains Randall C. 
Published: March 2011

ABSTRACTThe bonding of composites, thermosets, and thermoplastics via microwave energy is not only technically feasible but economically viable compared to conventional technologies.In recent years the growth in the use of composites, thermosets and thermoplastics has demonstrated the ability of these materials to fulfill specific performance needs in the automotive sector. In a contrary fashion the increased demand has served to focus attention on those factors which mitigate against further growth. In many instances this becomes a discussion of cycle times in primary or secondary operations.
Fundamentals of Microwave-Material Interactions and Sintering
Authors: Tinga Wayne R. 
Published: March 2011

ABSTRACTBasic interaction mechanisms are shown to depend strongly on the dielectric and magnetic properties of a process material. This causes a strong dependence of power absorption on frequency, material particle size, shape, temperature, and density. Sintering dynamics cause the microstructure of the treated material to change resulting in a change in microwave (1W) heating uniformity and rate. The concept of dielectric mixtures is introduced to predict the dielectric and heating properties of a host material with its inclusions in the form of shells, ellipsoids, spheres, disks and needles. Simplified models are described to give a process designer some insight into the behavior of MW sintering. Microwave power, by its very nature, gives better heating control and efficiency and provides internal heat to aid the material transport during sintering. No inherent temperature limit exists for MW sintering although refractory materials used to contain the process material create an artificial upper limit. It is shown that very high (1500–2000°C) temperatures in small samples can be readily achieved using commercial microwave ovens if appropriate MW transparent sample holders are used.
Economic Assessment of Microwave and Radio-Frequency Materials Processing
Authors: Sanio Michael R. , Schmidt Philip S. 
Published: March 2011

ABSTRACTDielectric heating has clearly demonstrated its production benefits in many materials processing applications. It is, however, a relatively expensive technology and its use vis a vis less expensive alternatives must be justified by a thorough economic analysis of all factors relevant to the given application. These include not only direct production costs, but also less easily quantified “implicit” factors such as product quality, reduced impact on the external environment, and improved workplace environment.An economic model which includes both production cost considerations and implicit factors in dielectric heating applications is under development. This paper will focus on the capital and operating costs of dielectric heating equipment and the factors which influence these costs. Capital and operating cost information was obtained from radio-frequency and microwave suppliers and consultants in the United States. Mail-out questionnaires were followed up by extensive telephone discussions to correlate and clarify data. The intent was to identify the major cost components of dielectric heating equipment and to summarize the qualitative and quantitative factors which affect them. Since microwave and radio-frequency equipment are distinctly different in design and application, they are treated separately.
Precision Microwave Applicators and Systems for Plasma and Materials Processing
Authors: Asmussen Jes , Garard Richard 
Published: March 2011

ABSTRACTModern applications of microwave energy have imposed new requirements upon microwave processing systems. Interest in energy efficiency, processing uniformity and control of process cycles has placed new design conditions upon microwave power oscillators, microwave systems and microwave applicator design. One approach of meeting new application requirements is the use of single-mode or controlled multimode applicators. The use of a single-mode applicator for plasma generation and materials processing will be presented. Descriptions of actual applicator designs for heating, curing and processing of solid materials and the generations of high and low pressure discharges will be given. The impact of these applicators on the total microwave system including the microwave power source will be described. Specific examples of applicator and associated microwave systems will be detailed for the applications of (1) plasma thin film deposition and (2) the precision processing and diagnosis of materials. Methods of process control and diagnosis, control of process uniformity and process scale up are discussed.
A Versatile Microwave Plasma Applicator
Authors: Ji Tian-Ren , Gerling John E. 
Published: March 2011

ABSTRACTThis paper describes a device used for the introduction of microwave energy into a plasma chamber over a wide area with high
transfer efficiency and good energy uniformity.The applicator design was based on a slotted waveguide combined with a quartz window. The impedance properties were calculated for
slots in the broad wall of WR430 waveguide. Low power simulating tests were conducted to determine the optimum geometry. A simple
test system was used to measure and plot the three-dimensional spatial energy distribution
Microwave Sintering of Ceramics
Authors: Varadan Vuay K. , Ma Yushieh , Lakhtakia Akhlesh , Varadan Vasundara V. 
Published: March 2011

ABSTRACTTheoretical considerations regarding microwave sintering of ceramics are discussed. It is shown how the rigorous application of multiple scattering theory may permit a better understanding of this interesting process. The possibility of thermal runaway being chaotic is discussed. Experimental results, and a possible connection to percolation theory, are also given.
Principles of Microwave Interaction with Polymeric and Organic Materials
Authors: Varadan Vijay K. , Varadan Vasundara V. , Lakhtakia Akhlesh 
Published: March 2011

ABSTRACTElectromagnetic waves can discriminate between objects of different handedness due to their transverse nature, which implies that the origin of chirality need not necessarily be molecular as in the case of optically active media. Effectively chiral composites may, therefore, be constructed by embedding chiral microstructures in non-chiral host media.
Medical and Biological Applications of Electromagnetic Techniques – a Relevant Experience to the Microwave Processing of Materials Research
Authors: Iskander Magdy F. 
Published: March 2011

ABSTRACTThe feasibility of using electromagnetic (EM) energy in industrial, medical, or in biological applications relies heavily on accurate knowledge of the dielectric properties of materials and on detailed understanding of the underlying interaction mechanisms. This chapter deals with the medical and biological applications of EM radiation. It therefore starts with a brief review of the dielectric properties of various tissues and a description of some of the basic interaction mechanisms. The techniques used to measure these properties are of particular interest to the microwave processing of materials research. Therefore, some of the time- and frequency-domain measurements methods of the dielectric properties of materials are discussed.Available techniques for calculating and measuring the absorption of EM radiation by humans and other biological models are also described. The impact of the obtained EM dosimetry results on modifying the ANSI Safety Standard is outlined. It will be noted that many of the dosimetric measurements procedures are highly relevant to experiences in the microwave processing of materials research.In addition, some of the medical applications in both the diagnostics and therapeutic areas are described. These applications basically exploit some of the unique dielectric characteristics of biological tissues. Specifically, noninvasive and interstitial EM hyperthermia techniques for cancer treatment are discussed, and other potential microwave methods for medical diagnostics are briefly reviewed. Future research needs to further the understanding of the various interaction mechanisms of EM radiation with materials are outlined. Every effort is made to relate experiences in the medical and biological research areas to research in the microwave processing of materials.
Impurity Redistribution In Ion Implanted Si After Picosecond Nd Laser Pulse Irradiation
Authors: Campisano S.U. , Baeri P. , Rimini E. , Russo G. , Malvezzi A.M. 
Published: March 2011

AbstractImpurity redistribution in Bi-implanted Si and in As-implanted Si has been investigated after irradiation with 25 ps Nd(λ=l.06 μm) laser pulse in the energy range 0.1–1.5 J/cm2 . Channeling effect in combination with 2.0 MeV He+ backscattering in glancing detection has been used to characterize the epitaxial crystallization, the impurity location and its depth distribution. The amorphous to single crystal transition occurs at an energy density of about 0.4 J/cm 2 . Bi atoms are located after crystallization in substitutional lattice sites for the in depth part of the distribution. Part of the Bi atoms accumulated at the sample surface and the amount of segregation increases with the pulse energy density and depends on the substrate orientation. A computer model has been also developed to calculate several parameters of interest, as the melt threshold,the melt duration, the carrier temperature etc including a detailed description of the absorption and of the energy relaxation processes. The calculations indicate that the simple thermal description accounts quantitatively for the experimental data on melt duration and impurity segregation.
Dopant Incorporation During Rapid Solidification
Authors: White C. W. , Zehner D. M. , Narayan J. , Holland O. W. , Appleton B. R. , Wilson S. R. 
Published: March 2011

ABSTRACTIncorporation of Group III, IV, V dopants in silicon occurs as a result of solute trapping during laser annealing. Distribution coefficients and substitutional solubilities are far greater than equilibrium values, and can be functions of growth velocity and crystal orientation. Mechanisms limiting dopant incorporation at high concentrations are identified and discussed.
Impurity Distribution Profiles and Surface Disorder after Laser Induced Diffusion.
Authors: Fogarassy E. , Stuck R. , Siffert P. , Broutet F. , Desoyer J. C. 
Published: March 2011

ABSTRACTA model for laser induced diffusion is proposed, assuming the melting of Si surface under pulsed laser irradiation and the diffusion ,in liquid phase, of a thin filmof impurity deposited according to the “limited source” conditions. Depending on the thickness of the film, it results in a dopant distribution profile with a surface disordered layer induced either by segregation effects or precipitation of the dopant in excess of the solubility limit achieved by laser annealing. Experimental results, obtained for a ruby laser irradiation of thin films of different impurities of group III and V, like antimony, bismuth, gallium and indium deposited on silicon substrates are in good agreement with the model. Their effective segregation coefficients have been deduced by fitting the experimental amount of dopant precipitated in the disordered surface layer with the numerical calculations. A cellular structure is seen on surface.
Defect Control During Epitaxial Regrowth by Rapid Thermal Annealing
Authors: Baumgart H. , Celler G. K. , Lischner D. J. , Robinson McD. , Sheng T. T. 
Published: March 2011

ABSTRACTRapid Thermal Annealing (RTA) with tungsten halogen lamps provides excellent regrowth of silicon layers damaged by ion implantation. In addition to minimizing dopant redistribution, the inherent advantage of this technique is good control of temperature gradients. The latter is instrumental in reducing the density of extended defects in the annealed samples. In contrast, solid phase laser annealing, which involves steep temperature gradients, always leaves interstitial dislocation loops and point defect clusters. We present a comparative study of crystal quality following laser processing and incoherent light annealing as well as furnace annealing of As, P and B ion implanted Si wafers.
A Detailed Examination of Time-Resolved Pulsed Raman Temeperature Measurements of Laser Annealed Silicon
Authors: Jellison G. E. , Lowndes D. H. , Wood R. F. 
Published: March 2011

ABSTRACTRaman temperature measurements during pulsed laser annealing of Si by Compaan and co-workers are critically examined. It has been shown previously that the Stokes to anti-Stokes ratio depends critically upon the optical properties of silicon as a function of temperature. These dependences, coupled with the large spatial and temporal temperature gradients normally found immediately after the high reflectivity phase, result in large variations in the calculated temperature depending upon the probe laser pulse width and the pulse-to-pulse and spatial variations in the annealing pulse energy density.
The Contribution of Beam Processing to Present and Future Integrated Circuit Technologies
Authors: Hill C 
Published: March 2011

ABSTRACTA brief history and present state of beam processing techniques and applications to silicon integrated circuit technology are given. The viability of incorporating pulse-laser controlled doping profiles into the emitter-base structure of an advanced bipolar transistor is discussed. The areas of present I.C. technology which will constrain future device development are identified, and the contribution that beam processing can make in removing these constraints is discussed. The beam processing techniques most likely to be found in future I.C. technologies are described.
Pulsed Excimer Laser (308 nm) Annealing Of Ion Implanted Silicon and Solar Cell Fabrication
Authors: Lowndes D. H. , Cleland J. W. , Christie W. H , EBY R. E , Jellison G. E. , Narayan J. , Westbrook R. D. , Wood R. F. , Nilson J. A. , Dass S. C. 
Published: March 2011

ABSTRACTA pulsed ultraviolet excimer laser (XeCl, 308 nm wavelength, 40 nsec FWHM pulse duration) has been successfully used for laser annealing of both boron- and arsenic-implanted silicon. TEM, SIMS, and sheet electrical measurements are used to characterize specimens. C-V and I-V measurements demonstrate that near-ideal p-n junctions are formed (diode perfection factor A = 1.2). Electrical activation of implanted ions by single laser pulses is essentially complete for energy densities Eℓ≥ 1.4 J/cm2 , far below the threshold for substantial surface damage ∽4.5 J/cm2. Melting model calculations are in good agreement with observed thresholds for dopant redistribution and for epitaxial regrowth. Changes in annealing behavior resulting from multiple (1,2,5) laser pulses are also reported. Finally, we demonstrate the use of scanned overlapping excimer laser pulses for fabrication of large area (2 cm2 ) solar cells with good performance characteristics. In contrast to pulsed ruby laser annealing, high open circuit voltages can be obtained without the use of substrate heating.
Processing Of Shallow (Rp<150Å) Implanted Layers With Electron Beams
Authors: Mcmillan G.B. , Shannon J.M. , Ahmed H. 
Published: March 2011

ABSTRACTThe multiple-scan method of electron beam annealing has been used to activate shallow (Rp<150Å), highly doped silicon layers produced by ion implantation of arsenic at 10keV. Beam conditions have been optimised (600Wcm−2 for 100ms) to produce essentially undiffused layers, as determined by high resolution SIMS, containing high concentrations of electrically active arsenic impurities. Computer modelling of diffusion effects in such layers has been used to identify optimum beam conditions and the calculations have been compared with experimental results. Hot electron device structures, which depend on negligible diffusion and high electrical activity, have been fabricated using the multiplescan method with a peak annealing temperature of 900°C.