Materials Literature
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The scanning tunneling microscope has been used to image a reduced TiO(2)(110) surface in ultrahigh vacuum. Structural units with periodicities rangng from 21 to 3.4 angstroms have been clearly imaged, demonstrating that atomic resolution imaging of an ionic, wide band gap (3.2 electron volts) semiconductor is possibl…
Correlations have been sought between Mossbauer spectral parameters and several crystal structure properties of Mg-Al oxide and silicate minerals hosting iron cations as minor constituents. Plots of isomer shift (I.S.) versus various bond length-related parameters, including mean metal-oxygen distance (R) of a coordin…
INTRODUCTION to the PHOTOTROPHIC BACTERIA and the USE of ELECTRON MICROSCOPY in THEIR STUDY. INTRODUCTION. PHOTOTROPIC PROKARYOTES. Introduction. Oxygenic Phototrophs. Cyanobacteria. Chloroxybacteria. Anoxygenic Phototrophs. Purple Phototrophs. Green Phototrophs. Heliobacteria. ELECTRON MICROSCOPY. Introduction. Scann…
A transition of brittle to ductile propagation of a sharp crack in a crystal is observed by molecular-dynamics simulation and the transition mechanism shown to be the emission of dislocations at the crack tip and activation of specific slip systems appropriate to the crystal structure. Implications for extension of cu…
Three series of dilute iron alloys, with oversized solutes, FeTi, FeV and FeMo, in the concentration range 50 at.ppm to 3 at.%, have been electron-irradiated at low temperature together with the metal. A strong dependence of the solute and defect resistivities on the solute concentration is observed, which is analysed…
An adaptive hysteresis current control technique where the hysteresis band is automatically modulated by the input voltage integrator without the load information to maintain the modulation frequency nearly constant is presented. The computer simulation for the proposed current controller has been done and the results…
With respect to the investigation of low pressure filament-assisted chemical vapor deposition processes for diamond formation, absolute concentrations of atomic hydrogen were determined by two-photon laserinduced fluorescence in the vicinity of a heated filament in an environment containing H(2) or mixtures of H(2)and…
An imaging Raman system based on a 2-D detector and capable of collecting simultaneously 1024 spatially resolved spectra has been constructed. Hardware and software are described which allow real time analysis of the spectral data, leading to a large reduction in the data storage requirements. The analysis yields a 1-…
Single crystals of Cu and Al were irradiated with 2.4*10 18 fast neutrons/cm 2 (E>0.1 MeV) at 4.6 K. Asymptotic diffuse scattering of X-rays was measured after irradiation and after several annealing steps up to 300 K. The formation of dislocation loops of interstitial and vacancy type was observed; their size distrib…
Polycrystalline diamond films deposited by the microwave plasma chemical vapor deposition (CVD) technique onto quartz substrates have been irradiated with 100 keV C and 320 keV Xe ions at room temperature and at 200 °C. The dose dependence of the electrical conductivity measured in situ exhibited complicated, nonmonot…
Stable icosahedral ${\mathrm{Al}}_{85\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{Ru}}_{15}$ (15x20) alloys of good metals are characterized by conductivities below the ``minimum metallic value,'' and resistivity ratios \ensuremath{\rho}(0.5 K)/\ensuremath{\rho}(295 K) as large as 4. Strong…
A comparative investigation of the influence of crystl lattice type on the character of primary processes, following irradiation with fast neutrons or heavy charged ions with low energies, is carried out with b.c.c., f.c.c., and h.c.p. structures. It is found that in all the cases sub-threshold stage generation of poi…
Penetration of primary electrons into crystals excitation of activator ions by incident radiation motion of mobile carriers in crystals energy conversion of electrons penetrated into phosphor crystals optimization of cathodoluminescence phosphors application of phosphors to picture tube rare earth phosphors II-VI comp…
1 Stereochemical and Physicochemical Properties of Hernes.- 1.1 Introduction.- 1.2 Electronic Structure of Iron.- 1.3 Stereochemistry of Metalloporphyrins.- 1.4 Properties of Ligands.- 1.5 Metal-free and Metal-substituted Cytochrome c.- 2 Spectroscopic Studies of Cytochromes.- 2.1 Introduction.- 2.2 Spectroscopic Meth…
β-KMo 2 P 3 O 13 cristallise dans P2 1 /c avec a=9,701, b=18,848, c=6,389 A, β=106,96°, Z=4; affinement jusqu'a R=0,025. Le reseau est fait de groupements MoO 6 , PO 4 , et P 2 O 7 delimitant des canaux ou reposent les ions K + . La structure est plus symetrique que celles des composes C s ou Rb
A new model of the hydrogen bond network in liquid water is developed. Using the technique of polymer science, the grand canonical partition function of water is expressed by the functional integral of the field variables. The method is applied to anomalies of liquid water. Using the mean-field lattice-gas approximati…
Li 3 B 7 O 12 cristallise dans P1 avec a=6,487, b=7,840, c=8,510 A, α=92,11, β=104,85, γ=99,47 o , Z=2; affinement jusqu'a R=0,061. La structure contient un reseau de mailles unitaires B 3 O 7 , B 3 O 8 et BO 3 avec des cations Li + situes dans les interstices
The empirical response function introduced by Cole and Davidson for the analysis of dielectric relaxation in the frequency domain has been used in an analogous way to reanalyze ionic conductivity relaxation using the electric modulus representation. The fitting of data for ionic relaxation in AgPO3, 0.1AgI-0.9AgPO3, a…
Electronic contributions to the optical properties of small silicon clusters are examined. Geometries and the electronic structures of the clusters are established using the tight-binding model, and linear as well as nonlinear polarizabilities of the clusters are evaluated using one-electron density matrix techniques.…
Transmission spectra of alkali borate glass films of known thickness have been studied as a function of film thickness in the frequency range 50–2000 cm−1, and the composition range 0–70 mol % Na2O. The apparent absorption coefficient of the Na+ ‘‘rattling’’ mode at ≊200 cm−1 becomes almost independent of film thickne…