Materials Literature
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Theories of toughness of materials depend on an understanding of the characteristic instabilities of the crack tip, and their possible interactions. In this paper we examine the effect of dislocation emission on subsequent cleavage of a crack and on further dislocation emission. The work is an extension of the previou…
Abstract The light transmittance of the gels of poly(vinyl alcohol) (PVA)/phenol/water solutions was examined for the entire range of phenol/water content. Excellent transparency was found for the gels with phenol contents of 70–95 vol %. In full consideration of the results for the transparency and melting temperatur…
Recently, two sets of single, double, and quadruple residue changes within the hydrophobic substrate binding pocket of Escherichia coli dihydrofolate reductase (5,6,7,8-tetrahydrofolate+ oxidoreductase, EC 1.5.1.3) were shown to exhibit nonadditive mutational effects [Huang, Z., Wagner, C. R., & Benkovic, S. J. (1994)…
Abstract UV degradation of polyimide films in air and vacuum were studied using UV‐visible, ESR, FTIR, and XPS spectroscopies. The UV‐visible spectra of polyimide films showed a blue shift in the absorption compared to Kapton. This behavior was attributed to the presence of bulky groups and kinks along the polymer cha…
Abstract Poly( L ‐lactide) (PLLA) and poly( DL ‐lactide) (PDLLA) blends were crystallized from the melt and their crystallization behaviors and morphologies were investigated using differential scanning calorimetry and polarizing microscopy. PLLA could crystallize from the melt in the presence of PDLLA when the PLLA c…
Nanometer-sized GaAs particles embedded in SiO2 were prepared by a digital rf-sputtering method, where GaAs and SiO2 targets were alternately sputtered in an Ar atmosphere. The GaAs deposition time was kept shorter than the time required to form a continuous layer. Transmission electron microscopy observations showed…
Anisotropic materials with layered structure, like MoS2 and WSe2, play an important role in a number of technologies. Some of these applications (lubrication, photovoltaics) require polycrystalline films oriented with their c axis perpendicular to the substrate surface (type-II texture), which is the thermodynamically…
We report the photodegradation of poly(p-phenylenevinylene) polymer when the film was irradiated with laser light at a wavelength corresponding to the peak wavelength of electroluminescence. Degradation in photoluminescent properties was significant in an air environment but not under vacuum. This indicates that the o…
The energies of most of the f-f crystal-field levels of NdGaO3 and neodymium-doped LaGaO3 crystals are given. The oscillator strengths of the J to J` Nd3+ absorption bands and of some zero-phonon transitions between individual Stark crystalline states have been determined at temperatures between 9 and 300 K for both c…
Epitaxial thin films of lanthanum-deficient LaxMnO3−δ (0.67≤x≤1) have been grown on (100) SrTiO3 substrates by pulsed laser deposition. The as-deposited films exhibit a ferromagnetic transition at temperatures ranging from 115 to 240 K, with the transition temperature (Tc) increasing with higher La deficiency. A sharp…
The piezoelectric strain coefficients have been measured as a function of composition for films in the PbZrO3–PbTiO3 (PZT) solid solution system, using a double-beam laser interferometry technique. This compositional dependence of piezoelectric, and the associated dielectric and ferroelectric properties for films 1 μm…
We have measured current–voltage characteristic, blue-violet electroluminescence (EL) and subgap photocurrent spectra of free standing polycrystalline chemical vapor deposited diamond film. The current increases as a power law function of the voltage with an exponent of about 5.5. The EL spectra show a main luminescen…
We have performed the first ab-initio calculations of a possible complex non-collinear magnetic structure in aluminium-rich Al-Mn liquids within the real-space tight-binding LMTO method. In our previous work we predicted the existence of large magnetic moments in Al-Mn liquids [A.M. Bratkovsky, A.V. Smirnov, D. N. Man…
The NdGaO3 and LaCa03 crystals are orthorhombic perovskites, belonging to space group D16 2h Pbnm. The Nd3+ spectroscopic properties including both optical absorption and emission in both compounds were measured at different temperatures between 9 and 300 K. Very high neodymium concentration is the reason for the quen…
The main deformation mechanism of shape memory alloys (SMA) are related to martensitic transformation and/or martensitic reorientation. These phenomena lead to heat production resulting from the transformation and/or from internal dissipation processes. As the SMA behaviour is strongly temperature dependent, its model…
The purpose of the present work is the direct measurement of the 5I7 → 5S2—5F4(Ho) excited state absorption in Gd3Gd5012 garnet with a two beam experiment. The result is compared with the cross-section deduced from the 5S2 – 5F4 → 5I7 emission spectrum, using Mc Cumber relations. The result is also compared to the las…
The plasma polymerization of naphthalene and octafluoronaphthalene using a DC glow discharge was performed. The prepared films were characterized by FT-IR and Raman spectroscopies, ESCA, ellipsometry, and contact angle measurements. The deposition rates of all of the plasma-polymerized films were high under general co…
The relationship between the polar (out-of-plane tilt) anchoring strength and the memory capability of surface-stabilized ferroelectric liquid crystal displays (SSFLCD) with rubbed polyimide (PI) surfaces as alignment layers has been investigated. The polar anchoring strength of nematic liquid crystals (NLC) on rubbed…
125Te nuclear spin relaxation (NSR) and electrical conducvitiy measurements were performed on single-crystalline paratellurite (α-TeO2) between room temperature and the melting point (1007K) at various oxygen partial pressures. A defect model is developed which fits the experimental data. The model involves ionic oxgy…
Investigations of the luminescence decay of Ce3+- and Tb3+-ions in solid solutions of the system K3La1−x−yCexTby(P04)2 were carried out at 298 K and 10 K using a laser pulse spectrometer or synchrotron radiation as excitation sources. A comparison of the decay times determined in the host absorption range (160 nm) and…