Materials Literature
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The physical and electrical properties of xPb(Sc1/2Nb1/2)O3-yPb(Mg1/3Nb2/3)O3-zPbTiO3(PSMNT 100x/100y/100z) ternary ceramic materials near the morphotropic phase boundary (MPB) were investigated. The MPB follows on almost linear region between the PSMNT 58/00/42 and PSMNT 00/68/32 MPB compositions of the binary system…
The Brillouin light scattering technique has been used to study the elastic properties of a number of silicon dioxide films deposited by plasma-enhanced chemical vapor deposition on Si substrates. In addition to stoichiometric undoped glass films produced from either silane or tetraethylorthosilicate, we have also stu…
Paramagnetic centers in Nb-doped BaTiO3 ceramics are measured at 77–500 K by electron paramagnetic resonance (EPR) for investigating the role of the centers on the well-known positive temperature coefficient of resistivity (PTCR) effect (PTCR at the Curie temperature). EPR detects four signals; an anisotropically broa…
The effect of fluorine addition on silicon oxide film properties as a function of SiF4/O2 gas flow ratio was investigated. The films were deposited by using electron cyclotron resonance plasma chemical vapor deposition with SiF4 and O2 as source gases diluted in Ar. Characterization of films was carried out in terms o…
The electrical degradation of (Ba, Sr)TiO 3 [BST] thin films as a function of the film thickness was investigated. BST thin films with various thickness were deposited on Pt/Ti/SiO 2 /Si substrates by in-situ RF magnetron sputtering. It was found that the electrical properties degraded markedly as the thickness of the…
The structure observed in concentrated polymeric micelles results from interactions between coronal chains that develop as micelles are brought to approach distances where the chains either compress or interdigitate. One powerful model for polymeric micelles comprises spherical particles with chains tethered to their…
Metal-insulator transition was observed in icosahedral quasicrystals ${\mathrm{Al}}_{70.5}$${\mathrm{Pd}}_{21}$${\mathrm{Re}}_{8.5\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$ as x changed from 5 to 0. It was found that conductivity data of the insulating samples (x\ensuremath{\leqslant}3.5) could be…
Ultraviolet light induced changes in polyimide liquid-crystal alignment films were investigated. Infrared, UV-visible, x-ray photoelectron spectroscopy, and electron-spin-resonance measure- ments indicated that bond breaking and subsequent oxidation reactions occur in polyimide films (SE7210, OCG284, DuPont 2555 and 2…
Abstract A variety of dendrimers up to generation 7 possessing terminal P(S)Cl 2 , (3‐[G 1 ]‐3‐[G 7 ]) or P(O)Cl 2 , (7‐[G 1 ]‐7‐[G 3 ], 7‐[G 3 , 7‐[G 7 ) have been tri‐ and tetrafunctionalized. Selective monosubstitution of P(X)Cl 2 (X = S, 0) termini with allylamine or propargylamine gave the trifunctionalized dendr…
Aromatic, fully conjugated polymers are a class of polymers attracting significant interest in academics as well as industry. In particular, poly-(p-phenylene) (PPP) and poly(p-phenyienevinylene) (PPV) are important materials due to their thermal stability and electrical conductivity after doping. Very recently their…
Abstract The reaction of ferric chloride and β‐diketones (HL) in alkaline methanol solution represents a good synthetic route to hexairon(III) clusters [MFe 6 ‐(OCH 3 ) 12 (L) 6 ] + (M = Na, Li), which exhibit an unusual sixfold molecular symmetry. Single‐crystal X‐ray diffraction showed that the six octahedrally coor…
New experimental techniques have been applied to the study of single-photon double ionization of atoms and molecules. A coincidence technique is described in which the spectra of nearly zero energy photoelectrons are recorded in two identical photoelectron energy analysers. The results are discussed in terms of the av…
Abstract Linear polyurethanes (PUR‐D k ) were prepared by reacting 4,4′‐methylenediphenyl diisocyanate (MDI) with low‐molecular‐weight diols HO(CH 2 ) k OH ( k = 2, 3, 4, and 6) and fractionated by precipitation or extraction with mixtures of N , N ‐dimethylformamide (DMF) and dibutyl ether (DBE). The fractions were…
Binary magnesium alloys containing chromium, manganese, or titanium were made using a physical vapour deposition technique. The corrosion resistance of the alloys was assessed in aqueous chloride solutions using total immersion tests in quiescent 600 mmol L−1 NaCI solutions. Alloying with manganese or titanium was fou…
By using a new impact test apparatus, the particle impact behaviour of ceramic materials at room temperature and elevated temperatures up to 1400°C and under tensile loads were carried out. Samarium cobalt spheres of 1mm diameter and 4mg mass were used as impact particles. The particle velocities ranged from 200 to 10…
Abstract Temperature dependencies of the conductivity and thermopower of bulk amorphous semiconducting alloys Zn 41 Sb 59 and Ga 100−x Sb x with 47.5 < x < 55 were measured at 80 to 370 K and 120 to 370 K, respectively. The samples were prepared by solid state amorphization of the quenched high pressure phases o…
Some of the features of the superspace description of quasiperiodic structures, of the so-called superspace embedding, can be arbitrarily chosen. The superspace approach is reviewed in such a way that these particular features, which are not intrinsic to the theory, are explicitly indicated and separated from the fund…
A theory of thermoelasticity for nonsimple materials is derived within the framework of extended thermodynamics. The theory is linearized, and a uniqueness result is presented. A Galerkin type solution of the field equations and fundamental solutions for steady vibrations are also studied.
The short-range order within amorphous polyaniline ($a$-PANI) has been studied through use of a pair-distribution-function analysis of x-ray scattering data in combination with quantitative refinements of model structure functions. Both the emeraldine base and salt (ES) forms of $a$-PANI are less planar than their cry…
Alumina reacts with 1 atm of SiF 4 below 660°± 7°C to form A1F 3 and SiO 2 . At higher temperatures the product is a mixture of fluorotopaz and AIF 3 . Mixtures of fluorotopaz and AIF3 decompose in 1 atm of SiF 4 at 973°± 8°C and form tabular α‐alumina. The equilibrium vapor pressure of SiF 4 above mixtures of fluorot…