Materials Literature
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We describe a convenient, one-step sol−gel route to composite polymeric organic−inorganic particles. The synthesis is based on performing the sol−gel polycondensation within a surfactant-stabilized emulsion of a solution of a polymer polystyrene of various molecular weights in tetraethoxysilane, with or without toluen…
There is currently a great need for solid state lasers that emit in the infrared. Whether or not conjugated polymers that emit in the IR can be synthesized is an interesting theoretical challenge. We show that emission in the IR can be achieved in designer polymers in which the effective Coulomb correlation is smaller…
Nonthermal secondary electrons with initial kinetic energies below 100 eV are an abundant transient species created in irradiated cells and thermalize within picoseconds through successive multiple energy loss events. Here we show that below 15 eV such low-energy electrons induce single (SSB) and double (DSB) strand b…
A numerical simulation of solidification process for AlSi8,7 alloy castings has been carried out. Numerical simulation with experimental temperature gradient and local solidification time have been compared for different boundary condition. A numerical simulation of solidification process have been executed by the pro…
Abstract An analytical technique based on electron spin resonance (ESR) has been developed to estimate the concentration of hindered amine stabiliser additives (HAS) in a polymeric formulation. Our method involves the conversion of the overall HAS derivatives into nitroxyl‐free radicals by exposure of the stabilised p…
Abstract For Abstract see ChemInform Abstract in Full Text.
Isopenicillin N synthase (IPNS) catalyses conversion of the linear tripeptide delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV) to isopenicillin N (IPN), the central step in biosynthesis of the beta-lactam antibiotics. The unsaturated substrate analogue delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-vinylglycine (AC…
The two-dimension dilute magnetic semiconductors (2D-DMS) Zn 1 - x Mn x Se·0.5L (L = ethylenediamine or en, 1,3-propanediamine or pda, 1,4-butanediamine or bda, and 1,6-hexanediamine or hda) and their host compounds ZnSe·0.5L were prepared by solvothermal reaction in solvent L at 190 °C. The powder X-ray diffraction p…
Development of clinically valuable porphyrin drugs for use in photodynamic therapy requires characterization of membrane effects on porphyrin excited-state dynamics and bimolecular quenching with oxygen. This study reports on the quenching of triplet-state tetraphenylporphyrin (TPP), 5-( p -carboxyphenyl)-10,15,20-tri…
The stability of the peroxide ligand bridging two manganese ions in the trinuclear oxomanganese complex [Mn(III)(3)(mu(3)-O)(mu-O(2))(AcO)(2)(dien)(3)](2+), one of only two structurally characterized Mn clusters possessing a mu(1,2)-peroxo bridge, has been investigated using density functional theory. Although the per…
Abstract The dynamic mechanical properties of a model system consisting of a styrene–butadiene (SB) symmetric block copolymer blended with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) have been studied. It is shown that PPO is effectively incorporated in the rigid domains of the material but that the distribution of t…
Abstract Microcapsules obtained by interfacial polycondensation from an original system based on the polyaddition of specific di‐ or polyamines and more classical acyl chloride molecules were studied. The originality of the system lies in the fact that the encapsulated agent is the internal phase allowing its incorpor…
This article is an account of the birth and evolution of surface science as an interdisciplinary research area. Surface science emanated from the confluence of concepts and tools in physics and chemistry with technological innovations that made it possible to determine the structure and properties of surfaces and inte…
In this work we report the synthesis and characterization of a new nanostructured platinum/tin/telluride inorganic/surfactant composite. The material is synthesized from soluble SnTe(4)(4-) clusters and is shown to have well-defined nanometer scale periodicity along with unique optical properties. Small-angle X-ray sc…
The reaction of Au(CH 3 ) 2 (acac) with the partially dehydroxylated surface of γ-Al 2 O 3 (calcined at 673 K) and the subsequent formation of supported gold clusters upon treatment of the supported species in He at various temperatures and 1 atm were investigated with infrared (IR) and extended X-ray absorption fine…
An analytical description for helical twisting in chiral liquid crystals is derived, which explores the correlation between the macroscopic properties of a liquid crystal and the parameters of single molecules. This theory is based on a simple model of a spiral-like rigid molecules that possess a limited number of par…
The aim of this paper is to review the actual data on the chemical bond in binary and mixed oxides. The electronegativity ( χ M ) and the acidity p a scales are the most significant semi‐empirical concepts for predicting the trend of bonding character in iono‐covalent oxides. A satisfactory correlation between the dat…
Using the controlled precipitation of silicic acid on functionalized polystyrene latexes, nanometer sized silica-coated spheres could be prepared and subsequently modified to allow dispersion in non-aqueous solvents; removal of the interior polymer by calcination resulted in the formation of hollow silica spheres.
Lymphatic distribution of interstitially injected poloxamer 407-coated nanospheres (45 nm in diameter) is controlled by surface configuration of the ethylene oxide (EO) segments of the adsorbed copolymer. At low poloxamer surface coverage, EO tails spread laterally on a nanosphere surface and assume a 'flat or mushroo…
General bonding principles are used to predict the structure of individual nanocrystals in nanocrystalline materials with semiionic bonding. The relationship between the general principles and actual nanocrystal structures is demonstrated using titanium dioxide in the anatase form. The proposed nanocrystals simultaneo…