Materials Literature
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The relations between fabric compression and friction are examined. It is found that the higher the fabric compression, the larger is the difference between the static- and kinetic-friction forces. The influence of some experimental variables such as normal load, area, and time of contact on frictional properties is a…
A detailed study of the layered manganite La 1+ x Sr 2- x Mn 2 O 7 has been performed, establishing that within the composition range 0.1 ≤ x ≤ 0.45 the phases crystallize in the I 4/ mmm space group. The evolution of structural parameters with x in this composition range has been followed using a novel application of…
The state of the art in proton conducting polymers is described and the interest in the use of sulfonamide groups to prepare a series of such polymers is stressed. The most relevant aspects of the chemical and physical characteristics of sulfamide are reviewed. Its history is briefly presented. A detailed description…
In this paper the active control of beam deflection through heating and cooling of Shape Memory Alloy (SMA) wires is examined. A phenomenological constitutive law for SMA wires is coupled with beam theory to provide predictions of beam shape upon temperature change in the SMA actuator. Both the linear and nonlinear be…
The hyperpolarizability β of an ionic species, 1-anilinonaphthalene-8-sulfonic acid ammonium salt (ANS), was determined in various solvents by the Hyper-Rayleigh scattering (HRS) technique. Increase in the solvent polarity led to a decrease in the hyperpolarizability; i.e. β=37.4±2.5×10 -30 esu in p-dioxane and β=10.3…
The effects of different nitrogen and carbon sources on cell growth, pH, and exopolysaccharide (EPS) and poly-(beta)-hydroxybutyrate (PHB) production by two strains of Rhizobium meliloti (M5N1 and Su47) are reported. Differences in the behavior of glucose- and fructose-grown cells were shown, in particular with the M5…
Three series of hydrogen bonded adducts have been formed between 4-alkoxy-4′-stilbazoles and the nitrophenols 4-nitrophenol, 3-nitrophenol and 2,4-dinitrophenol. Each series is mesomorphic displaying both nematic and smectic A phases, in sharp contrast to the behaviour of the individual components. The binary phase be…
Under the influence of extreme contact pressure and high factional heating, the real contact areas of diamond films may undergo phase transformation and gradual wear during long-duration dry sliding contacts. The wear debris particles that accumulate at the contact interface can then dominate the long-term sliding fri…
Abstract Constant pressure constant temperature molecular dynamics method is employed to investigate the atomistic scale dynamics of a model Bisphenol A polycarbonate in the vicinity of its glass transition temperature. First, the glass transition temperature and the thermal expansion coefficients of the polymer are p…
Abstract Whether crystalline or amorphous sp 3 ‐bonded carbon nitrides containing substantial amounts of nitrogen can be synthesized remains an open question. Various deposition techniques and high pressure syntheses to 40 GPa have not been successful thus far. The use of appropriately designed molecular or solid‐stat…
Diatom seasonal succession and interannual variability were studied using laminated sediments from Saanich Inlet, British Columbia, for the years 1900–1991. Frozen sediment cores allowed fine-scale sampling of laminae for each year. Thus, three ‘seasons’ for each year were identified based on species composition. Thal…
Inorganic–organic hybrids containing various inorganic components have been successfully synthesized from silanol-terminated poly(dimethylsiloxane) (PDMS) and three different inorganic sources, Al(OBu s ) 3 , Ti(OEt) 4 and Ta(OEt) 5 , by using a sol–gel process. Inorganic components as well as the process conditions w…
Porous clay heterostructures formed by surfactant assembly of open framework silica in the galleries of a smectite clay represent a new family of solid acid catalysts, as evidenced by the selective dehydration of 2-methylbut-3-yn-2-ol to 2-methylbut-3-yn-1-ene.
A bioresorbable aliphatic polyester was synthesized by bulk copolymerization of a 1/1 M/M L,L-lactide/epsilon-caprolactone mixture using zinc metal as initiator. The actual composition of the copolymer was found to be 1.5/1 as deduced from 1H NMR spectra obtained in DMSO-d6 solutions where higher resolution was obtain…
All articles of this category Transition metal phthalocyanines 3 a-g, 4e, f and 5 e, g substituted with sixteen alkoxy groups and various chain lengths were synthesized from the corresponding tetraalkoxyphthalodinitriles and characterized by spectroscopic methods. In the UV/vis spectra of the hexadecaalkoxy-substitute…
The pH-dependent reaction of [Ru(η 6 -C 6 H 6 )(D 2 O) 3 ] 2+ with adenosine and guanosine 5′-mono-, -di- and -tri-phosphates has been studied by 1 H and 31 P-{ 1 H} NMR spectroscopy. Diastereomeric µ-1κN 1 :2κ 2 N 6 , N 7 co-ordinated cyclic trimers of the type [{Ru(5′-AMP)(η 6 -C 6 H 6 ) } 3 ] predominate for adenos…
Potentiodynamic techniques were used to compare the effects of tolytriazole (TTAH) and benzotriazole (BTAH) corrosion inhibitors on anodic polarization behavior of copper in 1 M sodium chloride (NaCl). Variations in experimental procedure included the injection of inhibitor before commencing the potential scan, inject…
A convenient immobilisation of triazacyclononane ligands on a glycidylated surface leads to a new group of active, heterogeneous manganese epoxidation catalysts.
We report the preparation of transparent gels from concentrated sols of CdS nanocrystals. The principles of our method can be applied to other systems, enlarging the domain of the inorganic sol–gel process which so far has been restricted mainly to oxides.
The title compound (1) crystallites in the space group Pmn2(1) with a = \n13.110 (3), b = 5.813(1) and c = 6.482(1) Angstrom. Its crystal \nstructure was redetermined from three-dimensional single-crystal data \nto a final R-value of 0.0221. The Cd2+ ion is tetrahedrally coordinated \nto two sulfur ato…