Materials Literature
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We present new results on the zero-field magnetic relaxation in a single crystal of M${\mathrm{n}}_{12}$ acetate. We find three relaxation regimes. Above 2.8 K, the relaxation is exponential. Below this temperature, deviations are observed. These deviations are more pronounced when temperature decreases between 2.4 an…
The luminescence characteristics of laser-created bubbles in water have been studied for pressures between 1 and 15 bars. A fast peak in the luminescence is correlated with the first collapse point of the bubble. The width of the light pulse is several nanoseconds, and increases with the bubble size. With increasing p…
We have used an aqueous colloidal growth technique to form hybrid CdTe/HgTe quantum dots with a broad, strong fluorescence in the infrared (800–1200 nm). The quantum efficiency is high, around 44%, when pumped in the visible (488 nm), and the excited state lifetime is around 130 ns, making the material interesting as…
The biaxial and uniaxial magnetic anisotropy in epitaxial (100)-oriented La0.7(Sr, Ca)0.3MnO3 films on different substrates were measured by torque magnetometry in the range from T=20 K to room temperature. The biaxial anisotropy with easy axes 〈110〉 dominates and can be described by a cubic crystal anisotropy constan…
Ferroelectric BaTiO3 thin films with perovskite structure were grown by sol-gel spin-on processing onto (111)Pt/Ti/SiO2/Si substrates. In order to investigate the effects of space charge in BaTiO3 thin films, we measured the relative dielectric constant and the ac conductivity of the films as a function of frequency,…
A fundamental limitation on the recent development of nonvolatile ferroelectric memories in 64 Mbit–4 Gbit densities has been the ability to scale ferroelectric capacitor cell sizes below 1 μm2. In the present work, ferroelectric memory cells with lateral sizes down to 100 nm were fabricated by electron-beam direct wr…
Long-lasting phosphorescence is observed in Ce3+-doped Ca2Al2SiO7 (CASM) and CaYAl3O7 (CYAM) crystals at room temperature. UV irradiation at 365 nm produces broadband emissions with peaks at 417 nm for CASM and 425 nm for CYAM, which persist for not less than 1 h after the removal of the irradiating light. Based on th…
Accurate atomic coordinates of the room-temperature (root3xroot3)R30degree and low-temperature (3x3) phases of 1/3 ML Sn on Ge(111) have been established by grazing-incidence x-ray diffraction with synchrotron radiation. The Sn atoms are located solely at T4-sites in the (root3xroot3)R30degree structure. In the low te…
A detailed structural model for the indium-induced Si(111)-(4x1) surface reconstruction has been determined by analyzing an extensive set of x-ray-diffraction data recorded with monochromatic ($\hbarω$ = 9.1 keV) synchrotron radiation. The reconstruction is quasi-one-dimensional. The main features in the structure are…
The Mn-terminated (001) surface of the stable anti-ferromagnetic insulating phase of cubic perovskite CaMnO$_3$ is found to undergo a magnetic reconstruction consisting on a spin-flip process at surface: each Mn spin at the surface flips to pair with that of Mn in the subsurface layer. In spite of very little Mn-O cha…
The structure and properties of a geometrically constrained magnetic wall in a constriction separating two wider regions are investigated theoretically. They are shown to differconsiderably from those of an unconstrained wall, so that the geometrically constrained magnetic wall truly constitutes a new kind of magnetic…
The aging of an industrial thermoplastic elastomer polyurethane (TPU)-coated fabric, based on a polyether diol and an aromatic diisocyanate, is studied in artificial weathering tests. It is noticed that the degradation of this TPU-coated fabric leads to a weight loss, to the formation of a reticulated layer in sample…
This paper describes the process optimization in injection molding of high-density polyethylene (HDPE). Both conventional injection molding and shear controlled orientation (SCORIM) were employed in processing. The process optimization was based on design of experiments and complemented with analysis of variance. Mech…
In search of a better understanding of catalyst effects on final product qualities of polypropylene, an attempt was made to establish a correlation between catalyst type, polymer chain structure of homopolymers, crystallization behavior, as well as final morphology and mechanical properties. Conventional Ziegler–Natta…
Polymeric granules were prepared by matrix encapsulation containing 20, 35 and 50% (w/w) of natural liquid pesticide viz., Azadirachta Indica A. Juss. (neem) seed oil (NSO) per dry weight of urea formaldehyde crosslinked starch (UF-St), guar gum (UF-GG) and UF-(St + GG) matrices. Results of swelling and cumulative rel…
Wood could provide better service in some applications if it were harder and more dimensionally stable. In this study, wood–polymer composites (WPC) made with different chemical combinations were evaluated for dimensional stability, ability to exclude water vapor and liquid water, and hardness. Pine, maple, and oak so…
Residual softwood was thermomechanically pretreated and used to produce composites with no synthetic binders. The lignocellulosic material was steam exploded with a thermomechanical aqueous vapor process in a continuous tubular reactor. The study attempts to use the intrinsic bonding capacity of the steamed fiber, whi…
This paper describes the process optimization in injection molding of high-density polyethylene (HDPE). Both conventional injection molding and shear controlled orientation (SCORIM) were employed in processing. The process optimization was based on design of experiments and complemented with analysis of variance. Mech…
Maximum entropy method (MEM) charge density analysis has been carried out on synchrotron X-ray powder diffraction data of a series of anhydrous sodalites, M 6 (AlSiO 4 ) 6, M = Na, Ag, Tl. Analysis of the MEM electron densities reveals the nature of the interactions in the structures. The sodium atoms are bonded to th…
The adsolubilization of 2-naphthol by tetradecyltrimethylammonium bromide (TTAB) and by mixtures of TTAB and hydrophobically modified polyacrylamide (HMPAM) on Na-kaolinite was investigated. At concentrations of TTAB in the region of the CMC, only small differences were found in the amounts of 2-naphthol adsolubilized…