bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer Aukali-Metal Polyiodides with Variable Ionic and Electronic Conductivities
Authors: Loye Hans-Conrad Zur , Lyons Leslie J. , Hardy L. Charles , Tonge James S. , Shriver Duward F. 
Published: March 2011

AbstractAlkali metal polyiodide complexes of polyethers, of the type (polymer)nMIx, [Polymer - poly(ethylene oxide), PEO; poly(propylene oxide), PPO; or poly-(bis(methoxyethoxyethoxy)phosphazene), MEEP, and M - Li or Na] have been prepared and characterized in order to elucidate the nature of the observed ionic and electronic conductivities. Raman spectra of the polyiodide complexes indicate that the relative concentrations of the polyiodide species (such as I3- and higher polyiodides) depend on the salt concentration in the polymer as well as on the iodine to cation ratio. The ionic conduction can best be described by a free volume (VTF) mechanism where both polymer motion and ion mobility are activated processes. The magnitude of the electronic and ionic conductivities are a function of polymer to salt ratio as well as iodine content.
Polymer Electrolytes with Exclusively Cationic Conductivity
Authors: Liu H. , Okamoto Y. , Skotheim T. , Pak Y. S. , Greenbaum S. G. , Adamic K. J. 
Published: March 2011

AbstractThe synthesis of exclusively cation conducting polymer electrolytes based on a nylon-l backbone, ethylene-oxide side chains, and attached dibutyl phenolate anions is described. The tendency for ion pair formation appears to be reduced as the conductivity of the sodium-containing compound reaches −2 × 10−6 S-cm−1 at 50°C. 23Na nuclear magnetic resonance measurements demonstrate: i) motional narrowing of the mobile Na+ resonance above the glass transition temperature; ii) mobile Na+ concentrations of ∼75% at 40°C; iii) insensitivity of the linewidth to applied hydrostatic pressure up to 2 kbar. Similaries between these findings, and those in “conventional” polymer-salt electrolytes are discussed.
Proton Conducting Polymer Electrolytes for Possible Application In Electrochromic Display Devices
Authors: Singh R.P. , Gupta P.N. , Agrawal S.L. , Singh U.P. 
Published: March 2011

AbstractProton conduction in polymer composites of PVA+H3PO4 AND PVA+H2SO4 have been investigated. The films protonated by H3PO4 show protonic conductivity between 10−6to 10−3ohm−1cm−1 depending upon the relative ratios and temperature. H2SO4 protonated PVA films also show proton conductance of almost similar magnitude. The ionic transference number has been estimated to be 0.95 for H3PO4 protonated PVA film of ratio 70:30. The frequency and temperature dependence of electrical conductivity has also been carried out. These polymer films have been used to fabricate an electrochromic cell. The colorationtime determined from response time measurement for the system “SnO2|Glass|WO3 film|PVA film|SnO2 Glass” is 2.6 sec for H3PO4 doped films and 6 seconds for H2SO4 doped films.
EXAFS of Polymer Electrolytes
Authors: Cole M. , Latham R.J. , Linford R.G. , Schlindwein W.S. , Sheldon M.H. 
Published: March 2011

AbstractThe technique of EXAFS is reviewed and its application, especially to Ca- and Zn-polymer electrolytes, is considered. The implications of the EXAFS results for the interpretation of the electrochemical properties of these electrolytes are discussed.
The Electronic Transfer and the Formation of Cationic Intercalation Compounds
Authors: Rouxel J. 
Published: March 2011

AbstractLow-dimensional solids are known to be among the best host structures to practice intercalation chemistry. Besides geometrical aspects which play an important role but are now quite well understood, this paper emphasizes the relationship between chemical reactivity and the electronic structure of the host. A special attention is paid to the nature of redox centers involved in the intercalation process and to the connection between the phase diagram and the band structure of the host material.
Microstructures of The Electron-Beam Evaporated InSb Thin Films
Authors: Cheng D.J. , Yeh S. , Chi G.F. 
Published: March 2011

AbstractPolycrystalline InSb thin films have been prepared by the two-source electron-beam evaporation method. The InSb films have been grown on both pure Si (100) substrate and on Si (100) substrate which has been thermally oxidized to form a thin amorphous SiOx overlayer. The as-grown thin films have been heat treated under N2 atmosphere which is slightly mixed with air. A thin InOx layer is formed on the top surface of the thin film.After heat treatment, the InSb films grown on the oxidized Si substrate shows a preferred (111) orientation. While the films grown on Si substrate do not show such preferred orientation as evidenced by the X-ray diffraction patterns.The TEM cross sectional morphologies of the InSb film grown on oxidized Si substrate shows an ordered arrangement of the grains. While the film grown on the pure Si substrate shows a random arrangement of the grains. The film grown on the oxidized Si substrate also shows the existence of the twin boundary and an ordered arrangement of the precipitation of the second phase.
Structural and Electrical Characteristics of the Thermally Evaporated InSb Thin Films
Authors: Yeh S. , Cheng D. J. , Chi G. F. , Chu M. T. 
Published: March 2011

AbstractPolycrystalline InSb thin films have been prepared by the two-source thermal co-evaporation method. The InSb films have been grown on both pure Si (100) substrate and on Si (100) substrate which has been thermally oxidized to form a thin amorphous SiOx overlayer. The as-grown films have been heat treated under N2 atmosphere at different temperatures ranged from 520 to 535 C. Both as-grown films have (220) diffraction as the main peak. The heat treated films which have high mobility values show the (111) preferred orientation. For the heat treated film on oxidized Si substrate, the TEM cross sectional morphologies show the existence of the precipitaion of the second phase and the interface diffusion of InSb into the SiOx layer.
Structural Design and Synthesis of H3O+-β”/βAl2O3 and NH4-β”/β-Al2O3 Polycrystals
Authors: Nicholson Patrick S. 
Published: March 2011

AbstractThe synthesis and characterization of H3Oβ”/β-Al2O3 and NH4 + -H3O+β”/β-Al2O3 poly-crystals is described. The role of stress development and control in the intermediate stages of ion-exchange of the NaK-β”/βA12O3 ceramics is analysed and identifies the β-Al2O3 phase as acting as inert reinforcement for the two-phase composite. The Rb + ion-exchange of the intermediate K + β”/β-Al2O3 requisite for NH4+/H3O + ion-exchange to NH4-H3O+β”/βAl2O3 is described as also is the NH4NO3 exchange to the final ceramic. The total weight loss on heating NH4-H3O+β”/βAl2O3 polycrystals to 810°C is 7.4% which agrees with the value expected from the chemical formula. The 25°C conductivity of the grains of NH4 +-H3O + β”/βAl2O3 was 1.7 × 10−4 (ω-cm)−1 and the bulk conductivity was 3 × 10−5(ω-cm)−1.
Complex Defects in Lanthanide ion-Exchanged Beta Aluminas
Authors: Valergai Pedro , Jin Xianglin , Vozzo Frank , Roth Walter L. 
Published: March 2011

AbstractNa+ beta alumina crystals, ion-exchanged with Eu2+ and Nd3+, were studied using x-ray diffraction and optical spectroscopy. In partially-exchanged crystals, we found different concentrations of sodium and lanthanide ions in the two conduction planes of the unit cell. The results suggest that pairs of sodium ions are rapidly replaced by lanthanide ions in regions of the planes bridged by VAl-Ali-O-Ali-VAl extended defects.
Ion-Implanted Superionic Clusters
Authors: Feng Yiping , Wang Paul W. , Roth Walter L. 
Published: March 2011

AbstractAg+ was implanted in silica glass and beta alumina crystal and studied using particle backscattering and optical absorption. We found that Ag aggregates into colloidal metallic particles and when annealed diffuses toward the surface. The activation energy for diffusion is 0.14 eV in silica glass and 0.16 eV in beta alumina. Computer simulations indicate fast Ag+ diffusion is due to large concentrations of vacancies deposited along the track of the implanted ion. The high ionic conductivity of beta alumina promotes uniform spreading of the implanted layer.
Preparation of Thin Film Solid-State Electrochromic Device by Spray Pyrolysis Technique
Authors: Lee T. J. , Fey G. T. K. , Lin W. J. , Yao P.C. , Hsu S. E. 
Published: March 2011

Abstractin this study we report the use of a self-contained proton conductor, an electrochromic film of PWA, as the coating material for an energy-efficient window. The coating was prepared by spray pyrolysis method. The solar transmittance of the window can vary reversibly between 78% to 8%. The diffusion coefficient of PWA in decoloration is 2.8 × 10−12cm2/sec based on the calculation from the cyclic voltammetric data.
Macroscopic and Microscopic Aspects of Electron Hopping in Mixed Conductor Membranes using the Quasi-Fermi level
Authors: Buck Richard P. 
Published: March 2011

AbstractElectron transport in mixed conductor redox electrolyte membranes: anion/electron charge carriers, and cation/electron charge carriers are analyzed by irreversible thermodynamic methods appropriate to electrolyte transport. The generalized force for electron transport is the gradient of the Fermi level of electrons in electrolyte phases. The generalized force for ion transport is the gradient of the ionic electrochemical potential. New results include current-time, current-voltage, small amplitude and DC bias impedance functions.
Theory of Metal-Solid Electrolyte Interface
Authors: Kim S.I. , Seidl M. 
Published: March 2011

AbstractA comprehensive time independent theory of the solid electrolyte(SE)–metal electrode interface is presented, using the assumption that cations are the only mobile charge carrier in the electrolyte. The temperature and the dc current across the SE are the only free parameters for the solutions along with three intrinsic parameters which depend on the properties of the particular system. The phenomenological model of the interface double layer is based on the Gouy–Chapman–Stern model.The numerical solutions of the theory for porous tungstenzeolite system enables us to predict most of the properties in the SE system such as;the current–overpotential characteristics, the capacitances of the double layer, concentration profile in the diffusion layer, the potential profile across the interface, electrochemical exchange current, and the potential of zero charge(PZC) etc. An experimental technique to measure the PZC of SE systems has been also proposed.
Pore Structure Of Hydrated Cement Determined By Mercury Porosimetry And Nitrogen Sorption Techniques.
Authors: Abdel-Jawad Yahia , Hansen Will 
Published: March 2011

AbstractThe pore structure (i.e. total pore volume, surface area and pore-size distribution curves) was measured using mercury porosimetry and nitrogen sorption. Hydrated portland cement (type I) of water-cement (w/c) ratios 0.3, 0.4 and 0.6 by weight was analyzed at three degrees of hydration (i.e., 30%, 50% and 80%; 70% for the 0.3 w/c system) corresponding to low, intermediate and high levels of hydration. The effect of curing temperature (3°, 23°, and 43°C) on pore structure was also studied. The two techniques were evaluated as well on porous Vycor glass, which has a narrow pore size distribution in the size range accessible to both. Results obtained by both techniques on porous Vycor glass agreed well. However neither technique can be used alone to study the entire pore structure in well-hydrated cement due to the wide range in pore sizes and the presence of micropores. Due to the unstable pore structure in cement a specimen treatment procedure such as methanol replacement, combined with volume-thickness (V-t) analysis, is necessary in order to measure the micropores. At low hydration values the pore structure can be estimated by mercury intrusion porosimetry (MIP). At higher hydration values, however, this technique underestimates total pore volume and surface area due to the presence of micropores which MIP cannot determine. In the pore size range of overlap, higher pore volumes were obtained with MIP. Nitrogen V-t analysis shows that micropores are more pronounced with lower w/c ratios. This finding is consistent with pore size distribution curves obtained by MIP. For a given w/c ratio and degree of hydration the total pore volume measured by MIP was found to be independent of curing temperature in the temperature range studied. At any w/c ratio, capillary porosity is controlled by degree of hydration alone.
What Is Needed In A Permeability Test For Evaluation Of Concrete Quality.
Authors: Hooton R. Doug 
Published: March 2011

AbstractWhile there is presently a great deal of interest in measurement of permeability, there are a wide variety of non-standard methods reported. The author's experience combined with a critical review of the literature is that:
(a)results vary with operating variables of each test,(b)the coefficient of variation of results is large (typically 30 to 50%),(c)most methods cannot provide quantitative results in the range of interest for high strength, concretes and those containing supplementary cementing materials (10−15 m/s or less),(d)most methods do not represent the type of boundary conditions experienced by most critical concrete field conditions (i.e. fluid on one side and vapour on the other side),(e)Indirect measures of permeability such as rates of absorption, or resistivity measurements are easier to perform and relate directly to permeability.The activity of research in the area of permeability is similar to that described in the technical literature from the 1920's and 1930's. Much of that early work has abandoned for reason (c) above.It is attempted to review some of the previous experience, describe the problems and make suggestions for improved measurement of permeability.
Permeability Measurenents On Cement Paste
Authors: Banthia Nenkumar , Mindess Sidiney 
Published: March 2011

AbstractThe permeability of cement paste to water was determined by using a triaxial permeability cell. A new technique of specimen conditioning, based on cyclic flow reversal, was used for the early attainment of equilibrium flow conditions. Effects or cement type, age, and silica fume addition, were investigated. With the specimen conditioning used, equilibrium flow conditions were achieved on the first day of the test itself. The coefficient of permeability was found to decrease with an increase in the degree of hydration. The use of silica fume was found to decrease the permeability However, the permeability did not particularly depend upon the aotunt of silica fume added.
Gas Permeability of Concrete Up Till Pressure Difference of 100 Bar
Authors: Pihlajavaara S. E. 
Published: March 2011

AbstractIn modern society, concrete is one of the materials studied deeply in materials science, and, consequently, it is utilized also in high technology applications. However, the knowledge of gas permeability of concrete seems still to be poor and unreliable. Since 1980, the author has made both theoretical and experimental research to clarify the different aspects of gas permeability of concrete, especially for the applications in nuclear industry. A brief progress report of this work will be presented in this article.
Porosity In The Microstructure Of Blended Cements Containing Fly Ash
Authors: Patel H. H. , Pratt P. L. , Parrott L. J. 
Published: March 2011

AbstractThe changes in porosity of OPC and an OPC-fly ash blended cement during hydration have been studied at water/solids ratios of 0.35, 0.47 and 0.59, cured for times of up to 1 year at 25°C. The porosity was measured indirectly by methanol exchange and methanol adsorption techniques and, directly, by quantitative image analysis using backscattered electron imaging in the scanning electron microscope. Measurements of porosity and of remaining anhydrous material by image analysis showed good correlation with indirect methods. Measurement of the diffusion of methanol and of the compressive strength were made in parallel with the determination of the porosity during hydration and attempts were made to relate the properties to the microstructure. For both binders the reduction of total porosity with increased reaction was small. The major change in pore structure was the subdivision of coarse pores by gel to form finer pores. Compressive strength and diffusion properties were dominated by the relative volume of coarse pores.
Evidence for Minimal Pozzolanic Reaction in a Fly Ash Cement during the Period of Major Strength Development
Authors: Diamond Sidney , Sheng Qizhong , Olek Jan 
Published: March 2011

AbstractStrengths developed in fly ash concretes usually equal or exceed that of similar plain concrete after a few months, with much of the response usually attributed to “pozzolanic” reaction between ash and secondary calcium hydroxide (CH). The CH contents of pastes made with five different fly ashes were determined by DTA for periods up to six months. The CH contents found did not decrease notably over the period, and were substantially identical to that expected for plain cement pastes diluted with the same amount of inert material as the amount of fly ash used. Scanning electron microscope examination of the pastes showed only minimal evidence of reaction even up to 1 year of age, although many fly ash grains were in intimate contact with CH. Non-evaporable water contents of the fly ash pastes were substantially higher than expected at each age, suggesting that the fly ash promoted more complete cement hydration or that the hydration products formed bound substantially greater amounts of water than plain cement paste ordinarily does.
Early Stages of Oxygen Clustering and Its Influence on Electrical Behavior of Silicon
Authors: Oehrlein Gottlieb S. , Corbett James W. 
Published: March 2011

ABSTRACTOur knowledge of phenomena connected to the early stages of oxygen clusters, especially their electrical activity is reviewed. In addition to the well-known 450°C thermal donors, 'new oxygen donors', which occur in ca. 650°C annealing, have emerged in conjunction with low temperature processing for VLSI and are discussed. The existing models of thermal donors are reviewed. In a new model of thermal donor formation, thermal donors are viewed as metastable oxygen clusters which lower the compressive strain of the surrounding silicon matrix via bonding of 2p oxygen lone pair orbitals. It is shown how this bonding can result in shallow double donor states.
Transition Metal Impurities in Silicon
Authors: Weber Eicke R. , Wifhl Norbert 
Published: March 2011

ABSTRACTThe properties of transition metals in silicon are reviewed, emphasizing those observations which allow conclusions to be drawn with respect to microscopic defect models. 3d metals diffuse interstitially into silicon and stay predominantly in these sites at high temperatures. 3d elements lighter than Co can be quenched into these interstitial sites, giving rise to well-established energy levels. First theoretic calculations for these ions yield promising results. Co, Ni and Cu vanish out of the interstitial solution during quenching; an appreciable fraction of Cu may form pairs. The understanding of 4d and 5d metals in silicon is much less advanced at present, even for the technologically important elements Au and Pt. Some observations indicate that for Au and Pt pair formation might as well be important.
Structural and Chemical Microanalysis of Oxygen-Bearing Precipitates in Silicon
Authors: Carpenter R.W. , Chan I. , Tsai H.L. , Varker C. , Demer L.J. 
Published: March 2011

ABSTRACTPrecipitation in CZ-silicon during post-growth two-stage heat treatment has been examined using the methods of high resolution analytical electron microscopy. Electron transparent specimens prepared from these specimens, exhibited a low density of plate type precipitates on {100} planes. Microdiffraction experiments showed the precipitates to be consistently non-crystalline. Electron energy loss spectra showed that the precipitates contained oxygen, but carbon was not detected. It was found that carbon artifact absorption edges could be induced in spectra by specimen contamination in the microscope. The use of a low temperature stage eliminated this problem. Complementary characteristic x-ray microanalysis showed that metallic impurities had not segregated to these precipitates in this particular case, although this has been observed elsewhere.
Esr of Defects in III–V Compounds
Authors: Schneider Jürgen 
Published: March 2011

ABSTRACTA survey is given on deep defects in GaP, GaAs and InP identified by electron spin resonance (ESR). Defect structures to be discussed are (i) 3d transition metals, (ii) antisite defects and (iii) radiation induced centers. The relevance of such defects for the III–V materials technology will be illustrated by representative examples.
Dynamic Observation of Atomic-Level Events in Cadmium Telluride by High Resolution Tem
Authors: Yamashita T. , Sinclair R. 
Published: March 2011

ABSTRACTA conventional 120 keV high resolution TEM equipped with a TV camera has been used to make lattice resolution video recordings of cadmium telluride in the <110> orientation.The motion of dislocations and the migration of atomic species at the edge of the crystal have been studied. These processes are thought to be induced in the crystal by localized heating of the specimen by the electron beam. The observations are made on a TV monitor at a total magnification of 15 million times.
Electronic Properties of Grain Boundaries in GaAs: A Study of Oriented Bicrystals Prepared by Epitaxial Lateral Overgrowth
Authors: Salerno Jack P. , Mcclelland R. W. , Mavroides J. G. , Fan John C. C. , Witt A. F. 
Published: March 2011

ABSTRACTThe electronic properties of tilt boundaries with misorientation angles ranging from 0 to 30° in n-type GaAs bicrystal layers have been investigated. The current-voltage and capacitance-voltage characteristics are consistent with a double-depletion-region model. The height of the grain boundary potential barrier remains constant while the density of grain boundary states varies with misorientation angle. Deep level transient spectroscopy has revealed the presence of two bands of grain boundary states at approximately 0.65 and 0.9 eV below the conduction band. These states are attributed to bond reconstruction at the grain boundary.
Structural Studies of Metal-Semiconductor Interfaces with High-Resolution Electron Microscopy
Authors: Gibson J. M. , Tung R. T. , Poate J. M. 
Published: March 2011

ABSTRACTWe have studied interface atomic structure in epitaxial cobalt and nickel disilicides on silicon using high-resolution transmission electron microscopy. By employing UHV techniques during deposition and reaction we have grown truly single-crystalline NiSi2 and CoSi2 films on (111) Si and in the former case on (100) Si. These films are shown to be continuous to below 10Å thickness. By close control over preparation conditions, afforded by UHV, we can greatly influence the nucleation and growth of these films to the extent, for example with NiSi2 on (111)Si, of yielding continuous single-crystal films with either of two orientations as desired. Whilst in the (111) NiSi2 on Si system the interfacial structure invariably appears to well-fit a model in which metal atoms nearest to the interface are 7-fold co-ordinated, for (111) CoSi2 on Si agreement is generally better with a model involving 5-fold co-ordination of these atoms. A misfit dislocation core is also imaged. Results are discussed in the light of silicide nucleation and growth. The structure and stability of the (100) NiSi2 on Si interface is also considered.
Formation of Titanium Silicide At Atmospheric Pressure
Authors: Revesz Peter , Gyimesi Jeno , Gyulai Jozsef 
Published: March 2011

ABSTRACTTwo problems connected with the growth of Ti-silicide have been investigated. It is shown if a silicon dioxide step on a single crystal of silicon covered with titanium is annealed then, following vertical growth on the silicon part, lateral growth of Ti-silicide takes place over the oxide layer. We also studied the problems of Ti-silicide growthon samples implanted with high doses of Sb, As, P, Ar and O prior to Ti evaporation.