Materials Literature
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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…
The crystal structure of type neyite from Alice Arm, British Columbia, was determined from single-crystal X-ray diffraction data with the agreement factors R 1 = 0.037 (0.072 for all) and ω R 2 = 0.078. The structural formula supported by the new electron-microprobe data is AgCu 3 Pb 12.5 Bi 13 S 34 ( Z = 4); the latt…
Abstract An Erratum has been published for this article in Journal of Raman Spectroscopy 33 (2) 2002, 131. The dynamics of the lattice optical phonons in strontium titanate (SrTiO 3 ) thin films deposited on M‐plane sapphire [Al 2 O 3 (10 1 0)] substrate using the sol–gel route were investigated. A detailed study of t…
Cellulose derivatives like hydroxyethylcellulose (HEC) and carboxymethylcellulose (CMC) were submitted to the graftization reactions. The samples of HEC were grafted with monoisocyanate of poly(propylene oxide) (MPPO) and different diisocyanates of poly(ethylene oxide) (DPEO) and poly(propylene oxide) (DPPO) in the pr…
To improve the mechanical properties of granular corn starch-filled poly(ϵ-caprolactone) (PCL) compositions, three strategies were investigated including the hydrophobic coating of starch granules by reaction with n-butyl isocyanate, the addition of PCL-grafted dextran (PGD) as an amphiphilic compatibilizer, and the u…
The crystal structure of baricite, the Mg-dominant analogue of vivianite, (Mg 1.70 Fe 2+ 1.30− x Fe 3+ x )(PO 4 ) 2 (OH) x ·(8− x )H 2 O, a 10.085(2), b 13.390(3), c 4.6713(9) A, β 104.96(3)°, V 609.4(1) A 3 , space group C 2/ m , Z = 2, ρ calc = 2.440 g/cm 3 , has been determined [automated single-crystal diffractome…
From the stem bark of Bowdichia virgilioides, lupeol, lupeol acetate, sitosterol, stigmasterol and methyl-3-[2-(1-hydroxymethylvinyl)-2,3-dihydrobenzo[b]furan-5-yl]-(E)-2-propenoate have been isolated. The latter is a new compound and it has been named as bowdenol. Their structures were elucidated with the aid of spec…
Two homologous series are synthesized by fixing a rigid 4-methyl phenyl azo group to resorcinol moiety. In series I one phenolic -OH group is alkylated whereas, in series II both the phenolic -OH groups are alkylated. Monoethers of series I having free lateral hydroxy group due to strong hydrogen bonding, exhibit nema…