Materials Literature
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We demonstrated a method for measuring the quantum efficiency of deep UV emission using the two-step excitation and the difference of the integrated spectral intensities in Pr3+-doped CaAl4O7 and SrAl4O7 crystals. The quantum efficiencies of the emission from the lowest 4f5d state in the two systems have been estimate…
This is the second part of our study on needle heating in heavy industrial sewing. In this part, a finite element analysis (FEA) model is presented. Using a commercial FEA software system, ANSYS, the needle is modeled by a number of 3D bar elements and the sewing process is modeled by a series of time and space depend…
We describe an innovative yet straightforward method to obtain high quality thin sections of diatom exoskeletons for observation by scanning electron microscopy (SEM). The use of this new technique allows for clear observations of some ultrastructural valve features, including the raphe, which are generally difficult…
Dy3+-doped chalcogenide glasses are potential candidates for 1.3-µm optical-fiber amplifiers. We describe spectroscopic characterization of Dy3+-doped gallium lanthanum sulphide glasses with low and high oxide content. The spectroscopic investigations show that small amounts of oxide (∼1%) in low-oxide-content sulphid…
Polymer dispersed liquid crystal (PDLC) films consist of microdroplets of a liquid crystal dispersed in a polymer matrix. Their applications are based on the electrically controllable light scattering properties of the liquid crystal droplets. The effects of temperature on the electro-optical properties of PDLC films…
The strength of nearly all metallic and ceramic polycrystalline materials drops off rapidly with increases in temperature. Here we have developed a strong and tough oxide composite reinforced with a ductile phase at 1873 K with a different kind of microstructure, made by unidirectional solidification of an Al2O3-Y3Al5…
X-ray scattering evidence for macroscopic strong pinning centers in the sliding CDW state of NbSe3 , D. Rideau, P. Monceau, R. Currat, H. Requardt, F. Nad, J. E. Lorenzo, S. Brazovskii, C. Detlefs, G. Grübel
The toughness of amorphous precursor‐derived ceramics in the Si‐C‐N system is investigated. Crack‐growth data are obtained from DCB specimens, whereas the crack‐tip toughness is determined from the crack‐tip profile of indentation cracks. For amorphous Si‐C‐N ceramics that have been fabricated via the powder route, an…
The first results regarding the crystallization kinetics of the pure semisynthetic β-lactam antibiotic (SSA) ampicillin in water are presented. The experimentally obtained results at pH = 5 and T = 298 K are described well by the population-based crystallization model presented in this paper. The nucleation rate J (#…
The synthesis of new metal-free and zinc(II), cobalt(II) phthalocyanines substituted with four 4-(2-N'-cyanoethyl)aminoethylsulfanyl groups is described. The new compounds have been characterized by elemental analysis and IR, 1 H NMR and UV-vis spectroscopy.
Stereocomplexation between two enantiomeric polymers such as D-PLA and L-PLA have been described in the literature. No reports up till now have been published on the complexation between two non-identical complementary polymers. Stereocomplexes between poly(lactide) enantiomers and a representative peptide, LHRH, was…
Photodynamic therapy consists of the uptake of a photosensitizing dye, often a porphyrin, by tumor tissue and subsequent irradiation of the tumor with visible light of an appropriate wavelength matched to the absorption spectrum of the photosensitizing dye. This class of molecules produces reactive oxygen species when…
Diffractive optical element design is an important problem for many applications and is usually achieved by the Gerchberg-Saxton or the Yang-Gu algorithm. These algorithms are formulated on the basis of monochromatic wave propagation and the far-field assumption, because the Fourier transform is used to model the wave…
By using polarizing microscopy analysis we have found that several achiral homologues of the 4-n-alkyloxybenzoic acids, displaying only the nematic phase, exhibit the optical properties of a chiral liquid crystal system. These acids possess a mesophase due to the formation of dimers via hydrogen bonding. The microtext…
The present report presents results obtained from an interlaboratory test. 28 participants, mainly from industry and research institutes, measured glass transition temperatures (Tg) by differential scanning calorimetry (DSC) on four different polymers. The materials used were poly(methyl methacrylate) (PMMA), polycarb…
Nanometer-sized Si dot multilayers have been prepared by repeating a sequence of low-pressure chemical vapor deposition for dot formation and thermal oxidation for dot isolation. For the multilayer with Si dots in the range of 3–5 nm, the onset of photoconductivity is observable at a photon energy of 2 eV, correspondi…
Abstract We have synthesized and characterized a new heterometal dinuclear complex, [(nta)CrIII(μ-bpypz)FeII(picen)]BF4 (1), where nta = nitritotriacetate; bpypz− =3,5-bis(pyridin-2-yl)-pyrazolate; and picen = N,N′-bis-(2-pyridylmethyl)ethylenediamine. The X-ray structure of the Fe(II)–Cr(III)·H2O·3dmf demonstrated th…
The wicking kinetics of liquid droplets into yarns is studied using a computerized imaging system. A new method is suggested for characterizing the yarn structure by monitoring droplet absorption. The method is based on the comparative analysis of the time needed for droplet disappearance as a function of droplet volu…
Radical polymerization of methyl methacrylate with 0.5-2 mol% of the (meth)acrylate-substituted oxozirconium and oxotitanium clusters Zr6(OH)4O4(OMc)12 (OMc = methacrylate), Zr4O2(OMc)12, Ti6O4(OEt)8(OMc)8 and Ti4O2(OPri)6(OAcr)6 (OAcr = acrylate) results in an efficient cross-linking of the organic polymers. The obta…
Ten experiments were installed on acid soils in different ecoclimatic conditions of the Belgian Ardenne. Soil pH, exchangeable cations and P contents as well as foliar nutrient concentrations were monitored 1 and 3 years following the application of either (1) 3 t ha -1 of a dolomitic limestone or (2) 3 t ha -1 of a d…