Materials Literature
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Magnetic measurements on Ni _{2-x} Cu _{x} MnGa with 0 ≦ x≦ 0.8 are made in the temperature range between 4.2 K and 440 K. A phase diagram of Ni _{2-x} Cu _{x} MnGa is determined from the results of the temperature dependence of the initial permeability. The Curie temperature T_{C} increases with the Cu…
It has long been known that transitional metal ions and acids in iron gall inks induce degradation of paper support, thus endangering numerous historical materials. Stabilization treatment should therefore consist of deacidification and addition of antioxidants that could be used for stabilization of all historical ma…
In theory, both polarity and steric hindrance are basic factors which affect molecular interactions. To investigate the optical properties and steric structures of chiral compounds having different chiral moieties which affect the wavelength of light reflection in liquid crystal (LC) cells, a series of novel chiral co…
This paper compares smectic phases formed from LC‐homo‐ and LC‐co‐polysiloxanes. In the homopolysiloxane, each repeating unit of the polymer chain is substituted with a mesogen, whereas in the copolysiloxanes mesogenic repeating units are separated by dimethylsiloxane units. Despite a rather similiar phase sequence of…
Stop and play models with input-dependent shape functions are equivalent to the nonlinear Preisach model proposed by Mayergoyz. This equivalence engenders the necessary and sufficient conditions for a hysteretic nonlinearity to be represented by stop and play models that have input-dependent shape functions. A represe…
The concept of surface p K a is introduced and developed for self-assembled monolayers (SAMs). Students use a titration method to determine the p K a of 3-mercaptopropionic acid (MPA) in solution. At the same time they determine the surface p K a of a SAM of MPA on a gold electrode by running a series of cyclic voltam…
Experimental studies of the fracture kinetics of solids have shown that the process culminating in fracture of a stressed solid comprises a sequence of elementary events in which stressed atomic bonds are ruptured by local energy fluctuations. This recognition sparked investigations into elementary fracture events and…
Abstract New multifunctional, soluble and biocompatible polymeric systems exhibiting good physicochemical properties and good binding capacity have been obtained by assembly of smaller PEG components, selectively protected, purified and activated, by use of appropriate polyfunctional linkers. A general process for the…
Recent investigations of ultra fine-grained metals (Cu, Fe, Ni) performed within a Prague-Rossendorf-Ufa collaboration will be reviewed. The specimens were prepared by severe plastic deformation: the high-pressure torsion and equal channel angular pressing. Positron annihilation spectroscopy was used as the main metho…
Left-handed material (LHM) exhibiting negative permittivity and negative permeability in certain band has dispersive medium property varying with frequency. The effective permittivity and permeability function of this material have a similar form of Lorentz material model. Piecewise linear recursive convolution (PLRC)…
A study of the polymorphic transitions induced by annealing of fibers of syndiotactic polypropylene initially in the trans -planar form III and in the mesomorphic form is reported. Both the trans -planar form III and the mesomorphic form transform by annealing at high temperatures into a mixture of crystals of the ant…
Structural mechanisms and features of brittle and quasi-brittle fracture of nanocrystalline materials are theoretically analyzed. The role of size effects and internal stresses caused by a nonequilibrium structure during brittle trans-and intercrystallite fracture is studied. The dependence of the nanocrystalline mate…
An aluminum processing plant, which is located at the Antikyra Bay, at the northern margin of Corinth Gulf, is producing a high radioactive contamination in the marine environment, due to the discharge of bauxitic red mud tailings. The levels and the distribution of 238U, 232Th, 226Ra, 40K and 137Cs in marine sediment…
Stain repellent textiles are still a strong demand from textile industry as well as customers. Therefore, this work deals with an improved oleophobic treatment of PET textiles. Two polyester fabrics with different textile structures were examined, which requires a plasma treatment such as Ar/O 2 mixture enabling a goo…
Equal channel angular pressing (ECAP) has been used to process an Al–4·4 wt-%Mg alloy (AA5182) at room temperature (RT), 200°C and 400°C. The evolution of microstructure and mechanical properties after ECAP has been studied by metallographic observation, EBSD analysis and compression testing. The results show that ECA…
This paper presents the filament winding of revolution structures on a four-axis machine. A theoretical analysis is done in order to find the stable paths (geodesic) of the fiber on mandrel surface. In order to place the fiber along the stable path, the feed-eye trajectory, linear motion in two directions X and Z, and…
Recent progress in the synthetic chemistry and catalysis of polyoxometalates (POMs) is reviewed. The novel POMs and their derivatives emerging in nearly three years (2002–2004) are introduced, including POMs with novel structure, POMS-organic hybrid compounds and host-guest complexes. Our review is focused on the elab…
Abstract This article summarizes our recent efforts to chemical recycling of polymeric materials based on the equilibrium polymerization character of cyclic monomers. Spiro orthoesters ( SOE s), bicyclo orthoester, cyclic carbonates, and dithiocarbonates undergo ring‐opening polymerization to afford the corresponding…
Nach dem bisherigen Kenntnisstand haben geschweißte höherfeste Stähle die gleiche Ermüdungsfestigkeit wie geschweißte niedrigfeste Stähle. Um höherfeste Stähle auch in ermüdungsbeanspruchten Konstruktionen effektiv einsetzen zu können, bedarf es daher zusätzlicher Anstrengungen, um die Ermüdungsfestigkeit zu erhöhen,…
The transition temperature of high-density polyethylene (PE), low-density PE, and hydrogenated poly(butadiene), which was detected by the spin-labeled ESR method, was evaluated. The detected transition corresponded to the β transition of semicrystalline polymer PE. The transition temperature was found to depend on the…