Materials Literature
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Silsesquioxanes are a unique class of three-dimensional polyhedral silicon oligomers that have progressively begun to occupy a sizeable niche in polymer chemistry. This review focuses on the methods required to synthesize potentially useful silsesquioxanes, and takes a brief look at their applications as silicon-based…
SummaryConsiderable efforts are being made to improve the corrosion resistance of zinc coatings by alloying and application of compatible conversion coating treatments. These new systems have the potential for reliable and cost effective protective coatings on steel used in construction applications.The present invest…
The oxidation of carbothermally synthesised β′-sialon powder (z=2.45) was found by X-ray powder diffraction and solid-state 29 Si and 27 Al MAS NMR spectroscopies to result in the initial formation of amorphous SiO 2 and a non-crystalline mullite-like aluminosilicate which becomes crystalline at higher temperatures. T…
Layered double hydroxides (LDHs) containing cadmium as the divalent metal and aluminium as the trivalent metal have been prepared by coprecipitation from a mixed metal nitrate solution, and were obtained with nitrate and carbonate as the counter anions, and as single crystalline phases. XRD patterns show that these LD…
The strength of the “all-round (two-way) shape memory effect” and the work we can gain by using this effect were investigated. The alloy used was a Ti-51 (at%)Ni alloy. In order to align particles of Ti3Ni4 precipitate, plate-shaped specimens were aged at 773 K for 6 ks under several different tensile-stresses. Therma…
The use of shape memory alloy (SMA) wires as active tendons to reduce vibra-tion of a building model is analytically investigated. Approximate dynamic equations for one bay of a multi-story building with SMA tendons are derived based on laws of thermodynamics and Brinson's constitutive equations. These equations are u…
Influences of Ni impurity on the removability of primary scale in hydraulic descaling were investigated in 0.02 and 0.1 mass% Si mild steels. And the thickness distribution of residual scale was discussed in relation to the unevenness of the scale/steel interface. The removability of primary scale reduced due to the e…
We describe the growth and spectroscopy of well-defined mixed crystals of KH2PO4 (KDP) containing both natural and synthetic organic dyes in the {010} and {101} growth sectors. Our summary reevaluates historical dye inclusions, reveals others discovered in a directed screening, and ultimately describes dyes rationally…
The influence of cellular surface hydrophobicity on the adherence capacity to plastic of Candida albicans was investigated at two culture temperatures (37 and 22 degrees C). The majority of the 42 strains studied were hydrophobic at 22 degrees C and hydrophilic at 36 degrees C. The hydrophobic cells showed a consisten…
Ab-initio X-ray powder diffraction (see cover for typical spectra) is shown to be a powerful structural tool for (i) insoluble, thermally unstable, compounds which cannot be (re)crystallised from solution or from the melt; (ii) metastable phases destroyed or modified upon manipulation; (iii) twins; (iv) very small cry…
The creation of electrical contacts between selected copper rings on a commercial circuit board by a novel method is reported. The method relies on spatially coupled electrodissolution and electrodeposition mediated by an electric field, followed by electroless deposition. The Figure shows an example of a conductive w…
Inductively coupled, radiofrequency-induced plasmas of allyl alcohol, operated at low electrical power (1–8 W), have been investigated using mass spectrometry (MS) and deposition rate measurements. The solid, plasma polymer product was collected on silicon substrates and analysed by X-ray photoelectron spectroscopy (X…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTEthyne-Linked Cyclic Porphyrin Oligomers: Synthesis and Binding PropertiesAnton Vidal-Ferran, Zöe Clyde-Watson, Nick Bampos, and Jeremy K. M. SandersView Author Information University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, U.K. Cite this: J. Org. Chem.…
The techniques of X-ray powder diffraction and solid-state magic angle spinning (MAS) 23 Na, 27 Al, and 31 P nuclear magnetic resonance (NMR) spectroscopy have been combined to investigate the speciation in a series of glasses and glass ceramics of general formula (P 2 O 5 ) 0.45 (CaO) 0.24 (Na 2 O) 0.31-x (Al 2 O 3 )…
A one-dimensional material model of lead magnesium niobate (PMN) is presented. The model includes saturation phenomenology, but excludes hysteresis and dispersion. (Constant temperature is assumed.) It is shown that the strain can be taken to respond as an exactly quadratic function in the electric displacement D thro…
Hydroxyphenyl-substituted metalloporphyrins have been electropolymerized as films onto ITO substrates. An ether bond between the phenyl rings of two monomers links the porphyrin units, leaving the porphyrin macrocycles undisturbed. During electrochemical oxidation of the films using a 0.0−0.9 V potential window, a sin…
It is a well known fact that PD (partial discharge) affects the lifetime and the deterioration rate of an insulation. Research work has shown that a mixture of magnitudes and frequencies of PD may appear, depending on the type of the applied voltage, its frequency, the electrode arrangement, the type of the insulation…
The sensitivity of a porous silicon Schottky barrier photodetector is much improved through rapid thermal oxidation and rapid thermal annealing processes. Under our optimum preparation conditions, photocurrent can reach about 21 mA (under 22.4 mW/cm/sup 2/ tungsten lamp illumination) and dark current is about 5.4 /spl…
A test setup able to accommodate dish shaped electrodes for gaps up to /spl sim/20 cm is being used to study large gap effects. This experiment, in connection with other authors' experiments, underlines the three more characteristic aspects of the large gap case: a voltage effect, a current effect and a gas effect. Th…
The frequency dependent polarizability α(– ω σ; ω1) and the frequency dependent first hyperpolarizability β(– ω σ; ω1, ω2) have been calculated using both self consistent field (SCF) and multiconfigurational SCF (MCSCF) linear and quadratic response functions for six small molecules: BH, CO, HF, H2O, NH3, and H S. Two…