| Integrated Optical Fiber Lattice Accumulators |
MAR 97 |
75 pages |
| Authors:
Adam F. Atherton; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | Sigma-delta modulators track a signal by accumulating the error between an input signal and a feedback signal. The accumulated energy is amplitude analyzed by a comparator. The comparator output signal is fed back and subtracted from the input signal. This thesis is primarily concerned with designing accumulators for inclusion in an optical sigma-delta modulator. Fiber lattice structures with optical amplifiers are used to perform the accumulation. Two fiber lattice structures ... |
|
| Experimental Study of Parameters Involved in the Process of the Generation of Microwave Radiation by Compression of Ionic Crystals |
MAR 1997 |
31 pages |
| Authors:
David Morgan; C. Budd; BRITISH AEROSPACE PLC BRISTOL (UNITED KINGDOM)
|
| This report results from a contract tasking British Aerospace PLC as follows: The contractor will perform a service consisting of experimental study of parameters involved in the process of the generation of microwave radiation by compression of ionic crystals as described in his proposal. |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films: Nano-Meter, Binary Composites Produced from Liquid Precursors via Metastable Phases and Phase Partitioning |
28 FEB 97 |
12 pages |
| Authors:
Fred F. Lange; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| Chemical routes to synthesize inorganics start with solutions containing different metal-organic molecules that remain well mixed during evaporation to a solid precursor. The solid precursor decomposes and crystallizes during heating. Because decomposition (pyrolysis) occurs at very low temperatures relative to the melting temperature of the inorganic, a large free energy change exists for crystallization. This large free energy change is responsible for two very interesting phenomena. First, the size of ... |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films |
28 FEB 97 |
9 pages |
| Authors:
Fred F. Lange; CALIFORNIA UNIV SANTA BARBARA
|
| A polyvinylmethylsilane precursor has been used for the epitaxial growth of SiC thin films on 6H-SiC single crystal substrates. The films were prepared by dipping the single crystalline 6H-SiC substrates into the precursor polymer solution with subsequent thermal treatments at different temperatures. Transmission electron microscopy (TEM) was used to characterize the microstructure and chemistry of the different SiC films. At 1100 deg C, the film was amorphous and contained substantial ... |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films. Epitaxial Growth and Structure of Cubic and Pseudocubic Perovskite Films on Perovskite Substrates |
28 FEB 97 |
8 pages |
| Authors:
Fred F. Lange; P. A. Langjahr; T. Wagner; M. Ruehle; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| Cubic and pseudocubic perovskite films on perovskite substrates are used to study the influence of the lattice mismatch on the epitaxial growth of thin films on substrates of the same structure. For the growth of the films, a metalorganic deposition route (MOD) using 2-ethylhexanoates and neodecanoates as precursors, was developed. The decomposition of the precursors was investigated with thermogravimetric analysis (TGA) and x-ray diffraction (XRD). The films were spin-coated on ... |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films. Lattice Mismatch Accommodation in Perovskite Films on Perovskite Substrates |
28 FEB 97 |
37 pages |
| Authors:
P. A. Langjahr; F. F. Lange; T. Wagner; M. Ruehle; CALIFORNIA UNIV SANTA BARBARA COLL OF ENGINEERING
|
| Cubic perovskite films with different compositions were grown on perovskite substrates to investigate the influence of a large lattice mismatch on growth phenomena via the chemical solution deposition method, using toluene solutions of different 2-ethylhexanoates and neodecanoates. The films were pyrolyzed to crystallize the perovskite of the desired composition and then heated to 1000 deg C to promote epitaxial grain growth. Pole figures obtained via X-ray diffraction as well as ... |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films. Epitaxial Growth and Structure of Highly Mismatched Oxide Films with Rock-Salt Structure on MgO |
28 FEB 97 |
8 pages |
| Authors:
P. A. Langjahr; T. Wagner; F. F. Lange; M. Ruehle; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| CaO thin films were grown on (001) MgO single crystal substrates by a chemical solution deposition method to study the influence of a relatively high lattice mismatch (14%) on the epitaxial growth. In order to minimize an influence of a different crystal structure and chemistry between film and substrate, film and substrate were chosen to have the same structure (NaCl) and a similar chemistry. The films were heat treated until ... |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films |
28 FEB 97 |
34 pages |
| Authors:
Andrew D. Polli; Fred F. Lange; Carlos G. Levi; CALIFORNIA UNIV SANTA BARBARA COLL OF ENGINEERING
|
| The crystallization, transformation, and partitioning of amorphous PbO-ZrO2-TiO2 powders produced by pyrolytic decomposition of mixed alkoxide precursors were investigated. Materials have the general formulation Pb1+xTi1/ (1+PHI)ZrPHI/(1+PHI)O3+x, where -0.2<= x <= 0.2 is the fraction PbO excess/ deficiency and 0 <= phi <= 1 is the Zr/Ti molar ratio. Most compositions first crystallized as a metastable fluorite structure with varying degrees of pyrochlore-like cation ordering, which transformed to a single perovskite ... |
|
| Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films. Technical Reports 1 - 7 with a Technical Summary |
28 FEB 97 |
7 pages |
| Authors:
Fred F. Lange; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
|
| This program has emphasized two topics: (1) the crystallization of metastable, solid-solution structures, their partitioning into equilibrium structures and compositions, and the role of the metastable phase and its partitioning on forming unique, nanometer microstructures important to the mechanics of structural ceramics and their composites, and (2) the formation of single crystal thin films via spin coating single crystal substrates with solution precursors. Results for the first topic are new, ... |
|
| The Effect of Temperature on the Resonant Tunneling and Electric Field Domain Formation in Multiple Quantum Well Superlattices |
15 FEB 1997 |
4 pages |
| Authors:
Yuanjian Xu; Ali Xhakouri; Amnon Yariv; CALIFORNIA INST OF TECH PASADENA DEPT OF APPLIED PHYSICS
|
| Analyzing the photocurrent spectra and the I-V characteristics of weakly coupled GaAs/AlGaAs multiquantum well structures, different transport regimes are distinguished. At low temperatures (below ~50 K), due to the electron coherence over a few periods of the superlattice, electron transport is dominated by sequential resonant tunneling. At higher temperatures, evidences for the increased contribution of nonresonant transport processes, and the subsequent modification in the electric field distribution in the device, ... |
|
| Photorefractive Tungsten Bronze Materials for Optical Computing |
FEB 97 |
93 pages |
| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| The optical tungsten bronze BSTN and BSKNN single crystals were investigated for photorefractive and guided wave optical applications with considerable success. These materials have both high optical figure of merit and low dark conductivity, making them potentially important for pattern recognition and 3-D memory applications. Undoped crystals are advantageous for electrooptic devices such as guided wave for telecommunication and signal processing. Under this effort, advances were made in growth of ... |
|
| Vapour Phase Growth of Thick Monocrystalline GaN Epitaxial Layers by Sandwich-Method |
FEB 97 |
17 pages |
| Authors:
E. N. Mokhov; Yu. A. Vodacov; A. D. Roenkov; P. G. Baranov; M. E. Boiko; EUROPEAN RESEARCH OFFICE LONDON (UNITED KINGDOM)
|
| Comparison studies of the crystal quality of SiC substrates grown by Lely method and sublimation sandwich method (SSM) was conducted. SSM-substrates was shown to have considerably promise for high quality GaN epilayers growth. Conditions of the surface treatment of the SiC substrates were optimized for GaN epilayers growth. The best results were reached on very close to (0001) Si- substrate surfaces etched by sublimation technique. Monocrystalline GaN layers was shown ... |
|
| Proceedings of the 1997 Williamsburg Workshop on Ferroelectrics, Williamsburg, Virginia 2-5 February 1997 |
FEB 1997 |
|
| Authors:
ILLINOIS UNIV AT URBANA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
 | Enclosed are four (4) copies of the Proceedings from the Williamsburg Conference on Ferroelectrics that was supported by the subject grant. These copies are being submitted as the final report in accordance with the terms of the grant. The support provided by ONR is sincerely appreciated. |
|
| Development of Microwave Ferrites for High Performance Applications |
22 JAN 97 |
5 pages |
| Authors:
Vasantha R. Amarakoon; Vernon L. Burdick; Yong S. Cho; ALFRED UNIV NY
|
| LiZn ferrites were investigated to control the resultant microstructure or to obtain nanoscale powders at a low temperature. Two nonconventional chemical methods are introduced. The sol-gel coating procedure was used to uniformly distribute additives like SiO2 and Bi2O3. These oxides improved the densification of the LiZn ferrites at low temperatures via a liquid phase sintering. Nanocrystalline LiZn ferrites were obtained at a low temperature of 400 deg C via the ... |
|
| Crystal Chemistry of Ceramic/Metal Systems |
16 JAN 97 |
9 pages |
| Authors:
Robert R. Reeber; NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF GEOLOGY
|
| Robust models for predicting high temperature/pressure thermal expansion for a range of solids have been developed. The inter-relationships between several thermophysical properties including thermal expansion, specific heat, elastic properties, and self-diffusion of materials has been investigated. The role of defects on thermal expansion at high temperature and pressure has also been explored. During the course of the project several models for thermal expansion were developed extending earlier work of Reeber. ... |
|
| The Radiation Source through Periodically Modulated Structures |
15 JAN 97 |
5 pages |
| Authors:
Erich Gornik; TECHNISCHE UNIV VIENNA (AUSTRIA) INST FUER FESTKOERPERELEKTRONIK
|
| While the previous period was dedicated to studies of undoped field free GaAs/GaAlAs short period superlattices with different well widths, we have concentrated our activities in the 4th period of this project on the study of combinations of different superlattices using an advanced technique of hot electron spectroscopy. The basic idea of this structure is the development of a new injection structure which will allow the realization of an inverted ... |
|
| Synthesis of New Energetic Materials |
JAN 97 |
90 pages |
| Authors:
Alan P. Marchand; UNIVERSITY OF NORTH TEXAS DENTON DEPT OF CHEMISTRY
|
| Work on the synthesis of new hydrocarbon fuel systems involved: (a) a study of the synthesis and acid-promoted rearrangement of PCU-derived pinacols; (b) synthesis of an HCTD-derived pinacol; (c) a study of the generation and trapping of a PCU-derived vinylidenecarbene; (d) synthesis of 'homosecohexaprismane-10,13-dione'; (e) synthesis and thermal rearrangement of pentacyclo6.5.0.0(4,12).0(5,10).0(9,13)trideca-2,6-diene; (f) a study of the acid and base promoted reararrangements of hexacyclo11.2.1.0(2,12).0(5,10).0(5, 15).0(10,14)hexadeca-6,8-diene-4,11-dione. The results of studies that were ... |
|
| Electron Beam Analysis of Minor Element Site Occupancies in Ternary, Quaternary and Higher Order Duplex (gamma + alpha2) Titanium Aluminides |
JAN 97 |
77 pages |
| Authors:
C. J. Rossouw; P. R. Miller; M. A. Gibson; C. T. Forwood; COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANIZATION CLAYTON (AUSTRA LIA) DIV MATERIALS SCIENCE AND TECH
|
| Duplex gamma/alpha2 Ti-A1 alloys containing minor alloying additions of V Cr, Nb, Ta and their combinations have been examined by microanalytical electron microscopy to determine quantitatively the extent to which the additional alloying atoms: partition between the gamma and alpha2 phases; affect the state of atomic order, and occupy either Ti or A1 host sublattice sites. Partitioning between the gamma and alpha2 phases was determined using conventional energy-dispersive X-ray analysis. ... |
|
| InTISb for Long-Wavelength Infrared Photodetectors and Arrays |
97 |
22 pages |
| Authors:
Manijeh Razeghi; NORTHWESTERN UNIV EVANSTON IL CENTER FOR QUANTUM DEVICES
|
| The objective of this research program is to grow InTlSb alloys for long wavelength infrared detector applications by low pressure metalorganic chemical vapor deposition (LP-MOCVD) and to investigate their physical properties. As a first step towards this goal, optimum growth conditions for high quality InSb epitaxial films on InSb, GaAs, and Si substrates have been determined. InSb films grown under these conditions exhibited one of the best structural and electrical ... |
|
| Study of Fast Dynamics of Photorefractive Crystals |
97 |
64 pages |
| Authors:
Serguey Odoulov; UKRAINIAN SSR ACADEMY OF SCIENCES KIEV
|
| This report results from a contract tasking Dynamic Holography Group, Institute of Physics National Academy of Sciences as follows: The contractor will perform a service consisting of the study of fast dynamics of photo- refractive recording as described in his proposal. The contractor will examine adjusting frequency detuning of photo-refractive crystals by using ctro-optic modulation. |
|
| Defect Induced Lowering of Activation Energies at Step Bands in Co/ Cu(100) |
97 |
12 pages |
| Authors:
S. T. Coyle; M. R. Scheinfein; James L. Blue; ARIZONA STATE UNIV TEMPE DEPT OF PHYSICS
|
| Complex topological features such as rectangular voids and step inclusions that were seen in secondary electron micrographs of Co films grown on Cu(100) at room temperature were reproduced in Monte Carlo simulations in the presence of step bands. Lowered activation energies at defects such as steps, kinks, and vacancies enhance step edge restructuring during growth and upon annealing. This results in features such as faceted step edges, rectangular pits, incorporation ... |
|
| Current Challenges on Large Supramolecular Assemblies |
1997 |
121 pages |
| Authors:
Georges Tsoucaris; CENTRE PHARMACEUTIQUE CHATENAY-MALABRY(FRANCE)
|
| Over the last few years several breakthroughs in the Supermolecular (SM) domain have being accomplished or foreseen in the near future: (1) bigger molecules are being synthesis; (2) crystals with larger unit cells are being obtained; and (3) more and more molecular components are used to build SM compounds with increasing versatility in applications. This Conference will bring together experts in synthesis and chemical reactivity, in preparation of crystalline compounds, ... |
|
| A New Non-Rubbing Technique for Liquid Crystal Alignment |
1997 |
4 pages |
| Authors:
R. Shashidhar; K. Grueneberg; D. Shenoy; B. Peek; U. Kakarla; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR BIOMOLECULAR SCIENCE AND ENGINEERING
|
| A new non-rubbing technique for uniform, planar alignment of liquid crystals has been developed. It involves a combination of chemisorption and UV- induced photo-dimerization. By varying chemical structure of the outermost part of the alignment layer, it has been possible to control the pretilt of the liquid crystal molecules at the surface ranging from 0 to 20 degrees. A feature of the process is that ... |
|
| Demonstration of Gray Scale in Electroclinic Liquid Crystals |
1997 |
7 pages |
| Authors:
K. S. Nelson; J. W. Naciri; P. P. Bey; D. S. Cuttino; B. R. Ratna; NAVAL RESEARCH LAB WASHINGTON DC
|
| Liquid crystal (LC) materials possessing the chiral smectic A (Sm A) phase have been designed to yield high induced tilt angles and low response times. The primary objective of our work is to design materials that can provide the optimum tilt angle of 22.5 deg for applied voltages less than 5V/ micrometers, making them CMOS compatible. Optical response measurements to illustrate the feasibility of obtaining ... |
|
| The Influence of Crystal Orientation on the Corrosion Behavior of Aluminum |
1997 |
107 pages |
| Authors:
Brandon W. Davis; NAVAL ACADEMY ANNAPOLIS MD
|
| Observations have been made which indicate that the pitting of aluminum is crystallographic. When pure aluminum pits, the resulting morphology of the pit is composed of (100) orientations. Metastable and stable pitting was examined for (100), (110), and (111) aluminum single crystals and polycrystalline aluminum with 99.99% purity. Evidence was seen that the (111) orientation had a higher affinity for initiation and propagation and the (100) orientation had the least ... |
|
| Growth, Characterization and Device Development in Monocrystalline Diamond Films |
31 DEC 96 |
20 pages |
| Authors:
R. F. Davis; R. J. Nemanich; Z. Sitar; P. K. Baumann; S. P. Bozeman; NORTH CAROLINA STATE UNIV AT RALEIGH
|
| The electron affinity and Schottky barrier height of thin Cu and Zr films on diamond (100) substrates, cleaned at 500 degrees or 1150 degrees Celsius in UHV and terminated with oxygen or free of chemisorbed species, respectively, were correlated by means of UV photoemission spectroscopy. The achievement of NEA was dependent on the surface preparation before metal deposition and on the metal work function. The Schottky barrier height for clean ... |
|
| Defects and Impurities in 4H- and 6H-SiC Homoepitaxial Layers: Identification, Origin, Effect on Properties of Ohmic Contacts and Insulating Layers and Reduction |
31 DEC 96 |
42 pages |
| Authors:
R. F. Davis; M. O. Aboelfotoh; B. J. Baliga; R. J. Nemanich; S. W. King; NORTH CAROLINA STATE UNIV AT RALEIGH
|
| A dry ex situ cleaning sequence, superior to conventional wet chemical processing, and based on UV/O3 oxidation and exposure to the vapor of a 10:1 buffered HF solution for removal of non-carbidic C and silicon oxide, respectively, has been demonstrated via XPS analysis for (0001)Si 6H-SiC surfaces. Exposure to UV/O3 resulted in a broad Si-O Si 2p peak at 102.4 eV and a shift in the non-carbidic Cls peak from ... |
|
| Selected Energy Epitaxial Deposition and Low Energy Electron Microscopy of AlN, GaN and SiC Thin Films |
31 DEC 96 |
24 pages |
| Authors:
R. F. Davis; H. H. Lamb; I. S. Tsong; E. Bauer; E. Chen; NORTH CAROLINA STATE UNIV AT RALEIGH
|
| The stoichiometry and the atomic and electronic structure of the anion and cation terminated (0001) surfaces of GaN and AlN are being investigated using the multicenter tight-binding formalism. The surfaces are described within the slab-supercell formalism. Results show that an unreconstructed (1 x 1) surface is highly unstable with respect to surface reconstructions that change the surface stoichiometry of the outermost layers and, therefore, stabilize the atomic structure and eliminate ... |
|
| New Routes to Fluorinated Ligands and Polymers |
31 DEC 96 |
4 pages |
| Authors:
Russell P. Hughes; DARTMOUTH COLL HANOVER NH DEPT OF CHEMISTRY
|
| The first examples of perfluorobenzyl complexes of the transition metals have been prepared. Several complexes were characterized by X-ray crystallography, and the bond from the perfluorobenzyl ligand to cobalt, rhodium, and iridium appears to be unusually weak. While the perfluorobenzyl ligand in several cobalt complexes was shown to be unusually reactive towards coupling with ancillary ligands like pentam ethylcyclopentadienyl, no examples of insertion of fluorinated olefins into the metal-carbon bond ... |
|
| Growing and Releasing Diamonds. |
24 DEC 1996 |
|
| Authors:
Michael J. Marchywa; Pehr E. Pehrsson; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A process for making diamond and diamond products includes the steps of implanting ions in a diamond substrate to form a damaged layer of nondiamond carbon below the top surface of the substrate, heating the substrate to about 600-1200 deg C. growing diamond on the top surface of the heated substrate by chemical vapor deposition, and electrochemically etching the damaged layer to separate the grown diamond from the substrate along ... |
|
| Glass Matrix Doped with Activated Luminescent Nanocrystalline Particles. |
17 DEC 1996 |
|
| Authors:
Alan L. Huston; Brian L. Justus; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A luminescent glass includes nanocrystalline semiconductor particles, such as ZnS nanocrystals, and an activator, such as copper, for the particles. The glass is made by depositing the nanocrystalline semiconductor particles and the activator within a porous glass matrix, such as 7930 Vycor(TM) and then thermally activating the glass. The porous glass matrix may be at least partially consolidated or may be allowed to remain porous. The nanometer particle size permits ... |
|
| Ordered Piezoelectric Networks via a Liquid-Crystalline Monomer Strategy: Synthesis of the LC Monomer |
12 DEC 96 |
7 pages |
| Authors:
B. C. Baxter; D. L. Gin; CALIFORNIA UNIV BERKELEY DEPT OF CHEMISTRY
|
| Piezoelectric materials are used in many technological applications. The physical requirements for piezoelectricity are a high degree of bulk order and a noncentrosymmetric bulk structure. Conventional single crystal piezoceramics possess a high degree of order and long term stability; however, they are brittle and difficult to fabricate. Poled piezoelectric polymers offer ease of fabrication and processing; however, they lack long term thermal and mechanical stability. A new technique is described ... |
|
| Transformation Weakening of Ceramic Composite Interfaces |
06 DEC 96 |
71 pages |
| Authors:
Waltraud M. Kriven; ILLINOIS UNIV AT URBANA DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Phase stability and transformations in some chosen ceramics was investigated and several new transformations in oxide systems were identified. To quantitatively understand the coupling of mechanical shear stress to nucleation, a constrictive double shear test was devised. It indicated that a minimum debonding shear strength of 95 MPa was needed to overcome the nucleation barrier for the proto (orthorhombic) to clino (monoclinic) transformation in enstatite (MgO.SiO2) and to give rise ... |
|
| Vapour Phase Growth of Thick Monocrystalline GaN Epitaxial Layers by Sandwich-Method |
01 DEC 96 |
14 pages |
| Authors:
E. N. Mokov; Yu. A. Voda kov; A. D. Roenkov; P. G. Baranov; M. E. Boiko; JOINT STOCK CO AGENCY FOR SCIENCE AND TECHNOLOGY SAINT PETERSBURG (RUSSIA)
|
| We have modified a setup for growing GaN heteroepitaxial layers of large area and obtained 20 such structures on silicon carbide (SiC) and sapphire (Al2O3) substrates of 8 mm2 in size 50-150 micrometers thickness by Sublimation Sandwich Method (SSM). The substrates have been analysed for optimal GaN layer growth conditions, using the available data, and the results indicated that hexagonal SiC (alpha-SiC) is the best material. The substrate/epilayer mismatches may ... |
|
| Crystal Diffraction Spectrometry for Accurate, Non-Invasive KV/Spectral Measurement for Improvement of Mammographic Image Quality |
DEC 96 |
41 pages |
| Authors:
Richard D. Deslattes; Lawrence T. Hudson; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
|
| This contract has been devoted to the development and demonstration of the NIST prototype crystal spectrometer which was designed to provide accurate measurement of x-ray source voltage and full spectral characterization of the radiation emitted from mammographic x-ray sources. A major advance has been the movement from film to solid state image registration. Studies in a clinical environment led to refinements in packaging and portability, and revealed the need to ... |
|
| Electrical Characterization of Intrinsic and Induced Deep Level Defects in Hexagonal SiC |
DEC 96 |
394 pages |
| Authors:
James D. Scofield; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| Deep level defects in hexagonal SiC were studied using digital deep level transient spectroscopy (DLTS) methods over the temperature range of 100 to 800 deg K. New centers were found in bulk and epitaxial 6H-SiC with ionization energies between 0.38 to 1.3 eV, and levels from 0.2 to 0.856 eV were identified in 4H-SiC epitaxy. Direct correlation between inequivalent lattice sites was identified for energetic pairs associated with both vanadium ... |
|
| Materials Research Society Symposium Proceedings. Volume 448. Control of Semiconductor Surfaces and Interfaces. December 2-5, 1996, Boston, Massachusetts |
DEC 96 |
|
| Authors:
S. M. Prokes; O. J. Glembocki; S. K. Brierley; J. M. Gibson; J. M. Woodall; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| These proceedings consist of refereed papers presented at the symposium on "Control of Semiconductor Surfaces and Interfaces," held as a part of the 1996 MRS Fall Meeting in Boston, MA. Semiconductor surfaces and interfaces play a vital role in modern-day electronic devices. This is especially true as device dimensions shrink. The properties of clean surfaces and chemically processed surfaces can also have a significant impact on the properties of subsequently ... |
|
| Materials Research Society Symposium Proceedings. Volume 442. Defects in Electronic Materials II. December 2-6, 1996, Boston, Massachusetts |
DEC 96 |
|
| Authors:
Jurgen Michel; Thomas Kennedy; Kazumi Wada; Klaus Thonke; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| This proceedings volume contains oral and poster contributions from a symposium on "Defects in Electronic Materials" at the combined meeting of the Materials Research Society (MRS) and the International Conference on Electronic Materials (ICEM) in December, 1996, in Boston. The volume comprises the areas of defects in group III-V, and wide bandgap semiconductors. The symposium was planned to represent the general field of defects in electronic materials, with a focus ... |
|
| Materials Research Society Symposium Proceedings. Volume 449. III-V nitrides. December 2-6, 1996, Boston, Massachusetts |
DEC 96 |
|
| Authors:
F. A. Ponce; T. D. Moustakas; I. Akasaki; B. A. Monemar; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| The symposium reflected the large amount of work that has taken place in the last year, and much of the excitement that exists on this subject. The invited-talk program was designed to give a thorough review of the state-of- the-art in the field. The large number of contributions, in the form of talks and poster presentations, showed much progress in the growth and understanding of the III-V nitrides, and in ... |
|
| Dynamics in Small Confining Systems III. Symposium Held December 2-5, 1996, Boston, Massachusetts, U.S.A. Volume 464 |
DEC 96 |
394 pages |
| Authors:
J. M. Drake; J. Klafter; R. Kopelman; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| The fourth symposium on 'Dynamics in Small Confining Systems,' held as part of the 1996 MRS Fall Meeting, covered a broad range of topics related to static and dynamic properties of confining systems: probing of confined systems, structure and dynamics of liquids at interfaces, nanorheology and tribology, adsorption, diffusion in pores, and reactions. Participants from various disciplines shared different points of view on the questions of how ultrasmall geometries can ... |
|
| Nanophase and Nanocomposite Materials II. Symposium Held December 2-5, 1996, Boston, Massachusetts, U.S.A. Volume 457 |
DEC 1996 |
551 pages |
| Authors:
Sridhar Komarneni; John C. Parker; Heinrich J. Wollenberger; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| This volume contains the proceedings of the symposium "Nanophase and Nanocomposite Materials II," held in Boston, MA. on December 2-5, 1996, as part of the 1996 MRS Fall Meeting. The field of nanophase and nanocomposite materials has grown tremendously since the first symposium was held on this topic at the 1992 MRS Fall Meeting. The purpose of this second symposium was to provide a platform for the presentation and discussion ... |
|
| Electrochemical Synthesis and Modification of Materials |
DEC 96 |
580 pages |
| Authors:
Robert H. Pachavis; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| A new kinetic model for homoepitaxial growth on a singular surface is presented. The model combines the familiar rate equations approach and the concept of a feeding I zone that allows connection between the growth processes occuring in neighbouring monolayers. The model involves the irreversible 2D nucleation, growth and coalescence of islands in each growing monolayer and consists of an infinite set of coupled rate equations for the adatom and ... |
|
| Request for Nuclear Magnetic Resonance and X-Ray Crystallographic Instrumentation for North Carolina Central University |
26 NOV 96 |
4 pages |
| Authors:
Robert A. Izydore; NORTH CAROLINA CENTRAL UNIV DURHAM
|
| The purpose of the grant was to purchase a 300 MHz multinuclear nuclear magnetic resonance (NMR) spectrometer. The cost of the instrument was projected to be the funded amount of $243,058. Additionally it was projected $48, 950, was needed to renovate room 123 of the Hubbard Chemistry Building at North Carolina Central University (NCCU) to accommodate the instrument. The specific renovations needed were itemized in the proposal. The costs of ... |
|
| Method of Producing Si3N4 Reinforced Monoclinic BaO.Al2O3.2SiO2 and SrO.Al2O3.2SiO2 Ceramic Composites. |
26 NOV 1996 |
|
| Authors:
Inna G. Talmy; James A. Zaykoski; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A Si3N4 reinforced aluminosilicate ceramic composite made of A. from about 5 to about 40 weight percent of Si3N4 reinforcement material; B. from about 15 to about 35 weight percent of the recrystallization products formed from a molten glass composed of (1) from about 5 to about 16 weight percent of Al2O3, (2) from about 14 to about 45 mole percent of an alkaline earth oxide selected form the group ... |
|
| Investigations of the Optical and Electronic Properties of Crystalline Organic Semiconductors |
06 NOV 96 |
3 pages |
| Authors:
Stephen R. Forrest; PRINCETON UNIV NJ
|
| During the course of this program, major advances have been made in our understanding of the growth and optical properties of organic nanostructures. For example, we have found that a clear indication of quasi- epitaxial growth of an organic molecule is failure of the epitaxial layer to reduce strain by the generation of defects as films thickness is increased. Furthermore, studies of the optical spectra of closely packed molecules such ... |
|
| Synthesis and Studies of Aluminum-Nitrogen, -Phosphorus and Arsenic Cycles and Clusters |
04 NOV 96 |
6 pages |
| Authors:
Harold E. Guard; DUKE UNIV DURHAM NC DEPT OF CHEMISTRY
|
| The attempted dehalosilylation reactions between AlX3 (X = Cl, Br) and P(SiMe3)3 in toluene in 1:1 mole ratios afforded only the adducts Cl3Al. P(SiMe3)3 (1) and Br3Al.P(SiMe3)3 (2), respectively. Compounds 1 and 2 were characterized by 1H, 13C, 27Al, and 31P solution NMR spectroscopy, as well as partial elemental analysis. In addition, the solid state structures of the toluene solvates of 1 and 2 were determined by single-crystal X-ray analysis. ... |
|
| Biomimetic Fabrication of Functional Ceramic Composites |
NOV 96 |
4 pages |
| Authors:
C. Sukenik; A. Heuer; M. Deguire; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF CHEMISTRY
|
| Thin films and multilayers of functional ceramics have a number of important applications including dielectrics, magnetic recording media, piezoelectric transducers, and integrated optical devices. Variously functionalized self-assembled monolayers, attached to single-crystal silicon substrates, were used to direct the deposition of thin films of the oxides of titanium, zinc, iron, and zirconium, at low temperatures and ambient pressures. The films were uniform, adherent, and pore-free and were, in many cases, comprised ... |
|
| Low Temperature Epitaxial Growth of CoGe(001)/GaAs(100) Films Using the Partially Ionized Beam Deposition Technique |
NOV 96 |
16 pages |
| Authors:
K. E. Mello; S. R. Soss; S. P. Murarka; R.-m. Lu; S. L. Lee; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| The partially ionized beam (PIB) deposition technique was used to deposit CoGe2(001) thin films heteroepitaxially on GaAs(100) substrates for the first time. The epitaxial arrangement was CeGe2(001)/GaAs(100). It was found that the best epitaxy was obtained with an ion energy around 1100 eV and with a substrate temperature of 280 deg C. The wafers were treated only by immersion in HF:H20 1:10 immediately prior to deposition. Contacts grown at the ... |
|
| Biomimetic Fabrication of Functional Ceramic Composites |
NOV 96 |
4 pages |
| Authors:
Chaim N. Sukenik; Arthur H. Heuer; Mark R. De Guire; Rochael J. Collins; Hyun J. Shin; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF CHEMISTRY
|
| Thin films and multilayers of functional ceramics have a number of important applications including dielectrics, magnetic recording media, piezoelectric transducers, and integrated optical devices. Variously functionalized self-assembled monolayers, attached to single-crystal silicon substrates, were used to direct the deposition of thin films of the oxides of titanium, zinc, iron, and zirconium, at low temperatures and ambient pressures. The films were uniform, adherent, and pore-free and were, in many cases, comprised ... |
|
| Modeling of InP Crystal Growth by the MLEK Process |
31 OCT 96 |
47 pages |
| Authors:
Steven A. Orszag; Vadim Borue; Ananias Tomouboulides; Eytan Barouch; CAMBRIDGE HYDRODYNAMICS INC PRINCETON NJ
|
| The goal of this work is to achieve prototype simulations of the MLEK process for growth of InP crystals. We have made several key advances in this work, including numerical simulations of three dimensional time dependent low Prandtl number melt convection, with differential rotation, and magnetic fields. To do this we have developed a 3D general geometry spectral element code. We have demonstrated how rotation and, especially, differential rotation can ... |
|
Crystallography
