Materials Literature
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This work investigates the influence of storage of lysozyme in solution on its crystallization. The crystallization of hen egg-white lysozyme exhibits a storage effect (aging) that depends on the length of time the lysozyme solution is stored, after dissolving from freeze-dried powder, before being brought to crystall…
1 H NMR, electrical conductivity and thermal measurements have been performed on the rotator phase of n-alkylammonium chlorides CnH2n+1 NH3Cl (n= 6–10). Rapid two-dimensional self-diffusion and uniaxial rotation of the long rod-like cations were observed in all salts studied by measuring 1H NMR spin–lattice relaxation…
The role of boron compounds on the flame retardance characteristics of unmodified as well as surface-modified wood fiber-filled polypropylene composites is discussed. The effect of three different additives, m-phenylene bismaleimide (BMI), BMI-modified polypropylene (BPP), and a mixture of borax and boric acid, on the…
By introducing a head-group energy of adsorption with the grafting surface, we simulate the grafted polymer layer including chain exchange with the bulk solution using the bond-fluctuation model. The kinetics of adsorption is relatively rapid in short times and becomes much slower in later time as the layer is formed.…
Previous measurements of concentration gradients formed in long columns of supersaturated glycine solutions [1] indicate that small amounts of impurities, such as valine, can lead to an increase in the magnitude of the gradient. This might indicate that the impurity enhances the degree of cluster formation. The concen…
Acid-activated clays (montmorillonites) have been cation-exchanged with aluminium chloride pentahydroxide dihydrate (aluminium chlorhydrate, ACH) solutions of different concentrations to yield expanded materials. Various Al:clay (a/c) ratios have been used. The effect of changing the degree of polymerisation of the pi…
The glass-forming tendency of a large number of organic liquids of varying molecular shapes has been examined using differential scanning calorimetry (DSC) and a sharp distinction between spherical and non-spherical molecular liquids as regards their glass-forming efficiency is observed. Calorimetric evidence has been…
Abstract The new misfit layer compound (LaSe) 1.14 (NbSe 2 ) 2 has been synthesized from the elements at 1050‐ and its structure has been determined by a composite approach. The structure has an alternating stacking sequence of [LaSe] and two [NbSe 2 ] layers along the c direction. The misfit of the two different laye…
Species chemisorbed on diamond surfaces, which had been treated under CF4-plasma conditions, have been investigated by diffuse reflectance Fourier-transform infrared spectroscopy. Both oxidized and hydrogenated diamond surfaces were fluorinated at temperatures in the range 300–1000 °C. The C—F bond was observed on the…
Molecular dynamics simulations for γ-Al2O3 and La3+-doped γ-Al2O3 crystals have been performed. From bulk simulations a description of the crystal-terminating layers in both doped and pure alumina solids is reported. The molecular dynamics simulations allow us to describe systematically for the first time the surface…
Three alumina preparations, doped with ca. 3% CaO and corresponding to the γ-, δ,θ- and α-Al2O3 phases, respectively, have been studied by XRD, TEM and FTIR spectroscopy. Owing to the presence of Ca, no bulk phase stabilization/destabilization effects were observed, but the particle morphology of the γ- and α-phases w…
We review recent experimental studies of smectic A layering of asymmetric mesogens with emphasis on their relationship to phase transition physics. The formation of one and two dimensional lattices with long range order in the positions of the heads (tails) of molecules is considered as having either a polar or a ster…
Raman spectroscopy is nondestructive and relatively rapid and is well suited for the characterization of carbon films. The Raman spectra of a-C and a-C:H films consisting of two broad and overlapped features between 1000 and 1600 cm/sup -1/ have been obtained. Specific features in the Raman spectra are empirically cor…
Abstract Electrical conductivity and the Seebeck coefficient of compositions in the system Y 1- y Ca y MnO 3 and La 1- y Ca y MnO 3 were studied to determine the mechanism of electrical transport and defect structure. Electrical conduction appeared to occur via a small polaron hopping mechanism for compositions with 0…
Abstract Paramagnetic impurities, Fe 3+, Mn 2+and vanadyl (VO 2+) ions, along with paramagnetic radiation-induced defect centers, trapped holes, have been investigated with electron paramagnetic resonance (EPR) in more than 350 kaolin samples from different localities. The trace elements determined are either substitu…
The anodic polarisation behaviour of Ni–Ti shape memory alloy (SMA) in three different microstructural conditions, namely parent phase (β), martensite phase, and 30% cold worked martensite phase, was studied in simulated human body media, namely Hank's physiological solution and artificial saliva. Annealed 316L stainl…
Micelle-forming block copolymer–drug conjugates, Adriamycin-conjugated polyethylene glycol–poly(aspartic acid) block copolymers (PEG-P[Asp(ADR)]), were synthesized in eight compositions with varying chain lengths of the segments constituting the block co-polymer. The antitumor activity of this micelle-forming polymeri…
Abstract
Layered perovskite oxides of the formula ACa~,La,Nb3-,Ti,010 (A = K, Rb, Cs and 0 < x d 2) have been prepared. The members adopt the structures of the parent ACazNb3010. Interlayer alkali cations in the niobium-titanium oxide series can be ion-exchanged with Li+, Na+, NH4+, or H+ to give new derivatives. Intercalation…
Oxygen transport in many ionically conducting oxides occurs by diffusion or migration of oxygen-ion vacancies. An important issue in our understanding of these materials is the mechanism by which vacancies become trapped or ordered, and how this process affects transport. In this paper we reinvestigate the mechanism o…