Materials Literature
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Pb(Zr,Ti)O3 (PZT) and Pb(Zr,Ti,Nb)O3 (PNZT) thin films were grown on platinized silicon substrates by r.f. magnetron sputtering followed by a post-annealing treatment. The Niobium, Nb, concentration varied from 1 to 7 at.% by increment of 1 at.%. The effects of the Nb introduction on the PZT electrical properties, i.e…
A new species of Triceratiaceae is described for estuarine environments of Southern Brazil. The valve of Triceratium moreirae sp. nov. is triangular with elevations bearing ocellus and a rimoportula in their basis. The valvar surface has robust pseudoloculi, circular to polygonal, each one confining a group of areolae…
CysB is a positive regulator of transcription of genes involved in cysteine biosynthesis in Gram-negative bacteria and belongs to the large family of LysR-type transcriptional regulators. The full-length protein from Klebsiella aerogenes has been crystallized from solutions containing PEG 8000 in the presence and in t…
In our previous study, seam pucker simulation baased on mechancial calculation was proposed. Here, the simulation system is extended to consider collision between fabrics and seam pucker simulation of two strips of fabric is carried out. We adopt non‐linear bending rigidity observed in actual fabric tests and obtained…
Abstract A photochromic behavior was found for trans-4-diethylamino-4′-dimethylamino-2-hydroxychalcone in toluene, and colored species undergoing dark reaction to regenerate trans-isomer may be ascribed to cis-isomer with the lifetime of 77 min at room temperature. It is demonstrated that a trans→cis isomerization in…
In the past two years, three books have appeared on biological electron microscopy. The 2nd edition of the text by Glauert and Lewis appeared in 1998, the 2nd edition of the book by Bozzola and Russell appeared a year later and now, in the new millennium, we have the 4th edition of the book by Hayat. How well does thi…
The crystal structure of a new strontium borate, Sr 2 B 5 O 9 OH·H 2 O, space group C 2, a 10.2571(6), b 8.0487(2), c 6.4043(4) A, β 127.860(2)°, Z = 2, has been determined by X-ray diffraction using a single crystal grown under hydrothermal conditions. The structure is closely related to that of the zeolite-like hilg…
SiC–Mo 5 (Si,Al) 3 C composites were fabricated by the melt infiltration process, and the infiltration characteristics were studied in detail. Fracture strength and toughness were measured up to 1600°C using a three‐point bending test and indentation strength method, respectively. Both fracture strength and toughness…
At Bǎit ¸a Bihor (formerly Rézbánya), Romania, the type locality szaibelyite occurs in magnesian skarns hosted by the dolomitic marbles of Mesozoic age, near the contact with a granite -granodiorite body of Upper Cretaceous -Paleogene age.Associated minerals include calcite, dolomite, magnesite, kotoite, suanite, ludw…
A method for investigating the nature of thermally activated relaxations in terms of their cooperative character is tested in both polymer and low molecular weight crystal systems. This approach is based on analysis of the activation entropy in order to describe thermally activated relaxations. The betaine arsenate/ph…
Influence of the excitation frequency on CH4/H/H2 plasmas for diamond film deposition: electron energy distribution function and atomic hydrogen concentration, F J Gordillo-Vázquez, C Gómez-Aleixandre, J M Albella
Macrocyclic crystalline dibutyltin succinate (Bu2SnSuc) and adipate (Bu2SnAd) were prepared in high yields from Bu2SnO and dicarboxylic acid. According to vapor pressure osmometry and MALDI-TOF mass spectrometry, Bu2SnSuc is a cyclic trimer and Bu2SnAd a cyclic dimer. These macrocycles initiate a faster polymerization…
The basic mechanism for an one transistor memory device has been studied. Many ferroelectric materials such PbZrxTi1−xO3 (PZT), SrBi2Ta2O9 (SBT), Pb5Ge3O11 (PGO) etc. were analyzed for this application. Because of its low remanent polarization and low dielectric constant, the c-oriented Pb5Ge3O11 thin film was selecte…
We have investigated the formation and development of memory states in polymer dispersed liquid crystals induced by the application of a strong electric field. Both the optical transmittance and polarization field have been followed as functions of time. We have been able to distinguish between the contributions to th…
Blending of nitrile rubber with plasticised PVC produces vinyl-based thermoplastic elastomers. These materials offer a versatile range of properties and are used in numerous applications; such as glazing gaskets, footwear, cable jacketing, hose, tubing and coated fabrics. In this paper it is discussed how the properti…
Since the mid-1980s, there has been a growth of interest in the search and development of molecular second-order nonlinear optical (NLO) materials that possess various device applications. Beside the most traditional donor-acceptor (“push-pull”) organic chromophores (e.g. the stilbene family), chemists have increasing…
We study the transmission of light through different kinds of Fibonacci dielectric multilayers (FDM). We exploit a transfer matrix renormalization technique previously introduced by us [E. MaciÁ, Appl. Phys. Lett. 73, 3330 (1998)] to obtain closed analytical expressions for the transmission coefficient under arbitrary…
The Leibler theory [L. Leibler, Macromolecules 13, 1602 (1980)] for microphase separation in AB block copolymer melts is generalized for systems with arbitrary topology of molecules. A diagrammatic technique for calculation of the monomeric correlation functions is developed. The free energies of various mesophases ar…
The broadening of X-ray peak profiles and movements of tensile axes were obtained simultaneously in single-slip-conditioned copper single crystals. Two types of sample showed different tensile axis movements and slip system activities. These results are in accord with the observation of slip lines with scanning electr…
The current state of the art and future perspectives for protein crystallography with neutrons have been reviewed and discussed at an international workshop recently organized by the Hahn-Meitner-Institut (HMI) and Max-Delbrück-Center (MDC) in Berlin, and supported by the Neutron Round Table activity. The main topics…