Standard Nature of the Passive Layers of Buried Archaeological Bronze - The Example of Two Roman Half-length Portraits
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Corresponding States Hard-Sphere Model for the Diffusion Coefficients of Binary Dense-Plasma Mixtures
A recent free-energy model for charged Yukawa mixtures enables one to obtain, in simple analytic form, the diffusion coefficients of dense plasmas from those for ``effective'' hard spheres. This hard-sphere model was checked by new molecular dynamics simulations of highly asymmetric binary ionic mixtures to demonstrat…
Pulsed laser deposition of BaTiO3 thin films and their optical properties
Highly oriented a-axis BaTiO3 thin films were grown by pulsed laser deposition on (001) MgO substrates. The full width at half-maximum of the (200) BaTiO3 rocking curve was as narrow as 0.6°. A large hysteretic quadratic electro-optic effect was observed in a transverse geometry at 6328 Å. A birefringence shift up to…
Synthesis of oriented textured diamond films on silicon via hot filament chemical vapor deposition
Oriented diamond films were achieved on Si(001) and Si(111) substrates via hot filament chemical vapor deposition (HFCVD) with the orientation relationship of dia〈110〉//Si〈110〉 and dia(001)//Si(001) for Si(001), and of dia〈11̄0〉//Si〈11̄0〉 and dia(111)//Si(111) for Si(111). The substrates were negatively biased relativ…
Nonlinear Bubble Dynamics in a Slowly Driven Foam
Sudden topological rearrangement of neighboring bubbles in a foam occur during coarsening, and can also be induced by applied forces. Diffusing-wave spectroscopy measurements are presented of such dynamics before, during, and after an imposed shear strain. The rate of rearrangements is proportional to the strain rate,…
Comparison of Multibubble and Single-Bubble Sonoluminescence Spectra
Comparisons of the spectral characteristics of sonoluminescence from cavitation in bubble fields (MBSL) versus cavitation of single bubbles (SBSL) have been made for aqueous solutions under similar experimental conditions. In particular, alkali metal chloride solutions exhibit sonoluminescence emission from excited st…
Surface Layering in Liquid Gallium: An X-Ray Reflectivity Study
Surface-induced atomic layering in liquid gallium has been observed using x-ray reflectivity, ultrahigh vacuum conditions, and sputtered clean surfaces. Reflectivity data, collected on a supercooled liquid sample to momentum transfers as large as ${q}_{z}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3.0{\AA{}}^{\…
<title>Rigorous integral method in application to computing diffraction on relief gratings working in wavelength range from microwaves to x ray</title>
Application of rigorous integral method for computing the efficiency of arbitrary profile relief gratings used in all the optical spectral range is presented in this paper. The main progress of the method and the programs lays in numerical solution algorithm. In particular, an approximation of Green-function and its n…
Effect of quantum fluctuations on structural phase transitions in SrTiO_3 and BaTiO_3
Using path-integral Monte Carol simulations and an ab initio effective Hamiltonian, we study the effects of quantum fluctuations on structural phase transitions in the cubic perovskite compounds SrTiO3 and BaTiO3. We find quantum fluctuations affect ferroelectric (FE) transitions more strongly than antiferrodistortive…
STUDY OF SINTERING BEHAVIOR AND ELECTRICAL PROPERTIES OF Cu-Zn-Fe-O SYSTEM
Copper zinc ferrites ( Cu 1−x Zn x Fe 2 O 4 ) with x = 0.1, 0.2, 0.3 were prepared by solid state reaction technique. The samples were presintered at 900°C for 40 to 45 hrs and finally at 950°C for 4 hrs followed by air quenching. The lattice parameter, X-ray densities (D m ), grain size, bulk densities (D) and porosi…
Structural and Photophysical Properties of Pseudo‐Tricapped Trigonal Prismatic Lanthanide building blocks controlled by zinc(II) in heterodinuclear df complexes
Abstract An efficient combination of electrospray mass spectrometry (ES‐MS), spectrophotometric and 1 H‐NMR titrations in solution is used to characterize the assembly of the segmental ligand 2‐{6‐[1‐(3,5‐dimethoxybenzyl)‐1 H ‐benzimidazol‐2‐yl]pyridin‐2‐yl}‐1, 1′‐dimethyl‐5,5′‐methylene‐2′‐(5‐methylpyridin‐2‐yl)bis[1…
Theory of interstitial oxygen in silicon and germanium
The interstitial oxygen centers in silicon and germanium are reconsidered and compared in an analysis based on the first-principles total-energy determination of the potential-energy surface of the centers, and a calculation of their respective low energy excitations and infrared absorption spectra. The total-energy c…
Statistical design in isothermal aging of polyimide resins
Abstract Recent developments in research on polyimides for high temperature applications have led to the synthesis of many new polymers. Among the criteria that determines their thermal oxidative stability, isothermal aging is one of the most important. Isothermal aging studies require that many experimental factors a…
Dynamical Jahn-Teller Effect and Berry Phase in Positively Charged Fullerene I. Basic Considerations
We study the Jahn-Teller effect of positive fullerene ions $^2$C$_{60}^{+}$ and $^1$C$_{60}^{2+}$. The aim is to discover if this case, in analogy with the negative ion, possesses a Berry phase or not, and what are the consequences on dynamical Jahn-Teller quantization. Working in the linear and spherical approximatio…
Heteroepitaxial growth of highly conductive metal oxide RuO2 thin films by pulsed laser deposition
Highly conductive ruthenium oxide (RuO2) has been epitaxially grown on LaAlO3 substrates by pulsed laser deposition. The RuO2 film is (h00) oriented normal to the substrate surface. The heteroepitaxial growth of RuO2 on LaAlO3 is demonstrated by the strong in-plane orientation of thin films with respect to the major a…
Angle Resolved Energy Correlated Coincidence Electron Spectroscopy of Solid Surfaces
We report on the first measurements of the angle resolved energy distribution of correlated electrons created in single scattering events by low energy ( ${E}_{p}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}14$--25 eV) electrons. We combined coincidence and time-of-flight techniques to measure simultaneously ene…
Orientational Ordering in Spatially Disordered Dipolar Systems
This Letter addresses basic questions concerning ferroelectric order in positionally disordered dipolar materials. Three models distinguished by dipole vectors that have one, two, or three components are studied by computer simulation. Randomly frozen and dynamically disordered media are considered. It is shown that f…
Commensurate and Incommensurate Spin-Density Waves and a Modified Phase Diagram of the Bechgaard Salts
We have performed transport and $^{13}C$ NMR measurements on the sulfur-based Bechgaard salt, (TMTTF${)}_{2}$Br, at different pressures. At low pressures the ground state antiferromagnetism is commensurate with the lattice, while at high pressures many signatures of incommensurate density waves are found. Evidence tha…
Diamond polytypes in the chemical vapor deposited diamond films
Micro-Raman spectroscopy and x-ray diffraction measurements have been used to identify the presence of hexagonal diamond polytypes in chemical vapor deposited diamond films. The presence of additional reflections, in addition to the normal cubic diamond reflections in the diffraction spectra and bands at 1306 and 1193…
Colossal magnetoresistance of 1 000 000-fold magnitude achieved in the antiferromagnetic phase of La1−xCaxMnO3
Record values of colossal magnetoresistance (CMR) have been achieved in the antiferromagnetic phase of the La1−xCaxMnO3 system. At 125 K, the CMR of the La0.5Ca0.5MnO3 reaches nearly 1 000 000%. It increases exponentially to 100 000 000% at 57 K. While the ground state is primarily an antiferromagnet, application of a…