Materials Literature
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In a number of nitrogen-fixing bacteria, nitrogenase is posttranslationally regulated by reversible ADP-ribosylation of dinitrogenase reductase. The structure of the dinitrogenase reductase from Azotobacter vinelandii is known. In this study, mutant forms of dinitrogenase reductase from A. vinelandii that are affected…
We fabricated field-emission vacuum microelectronic devices such as diode and triode devices, using high-resolution electron-beam lithography in combination with the reactive ion etching (RIE) technique. The turn-on voltage of the diode is 13 V, which is the lowest value reported for single-crystalline lateral silicon…
We investigated the behaviour in tension and at room temperature of TiNi shape memory alloys in martensitic state. Our first experimental results show that two deformation mechanisms are involved in the behaviour of such materials: martensite platelets reorientation and irreversible plasticity. Moreover when irreversi…
Periodic domain patterns have been observed in a nematic liquid crystal cell induced by an elastic wave which propagates on a glass plate over a wide frequency range. The frequency dependence of the periodic length of the domain pattern is measured and a numerical analysis of elastic wave propagation is carried out in…
Abstract We report the long‐term stability and improved brightness and efficiency of the brightest known non‐filtered EL phosphor Ga 2 O 3 : Eu. A high brightness of 840 cd/m 2 is maintained for a single‐insulating device for over 2500 hours at 370V/650 Hz. We demonstrate the inherent stability of the rf sputtered dev…
Perovskite-type Nd0.7Bao0.3MnO3 has been synthesized and its magnetic and magnetotransport properties studied in the temperature range from 5 K to 300 K. X-ray diffraction indicates that the crystal-symmetry is orthorhombic with a=0.5508(1) nm, b=0.5496(2) nm, and c=0.7764(3) nm. There exist two magnetic phase transit…
The crystal structure of the mesoionic compound 2-oxo-3-benzoyloxazolo[3,2-a]pyridine (C 14 NO 3 H 9 ) has been determined from X-ray powder data using the grid search procedure. The crystal symmetry is orthorhombic (space group Pna2 1 , a=7,940(1) Å, b=24,562(3) Å, c=5,402(1) Å). The results of Rietveld refinement (R…
The present study describes the fabrication and characterization of cluster diamond (CD) dispersed Cu composites. A powder metallurgy method combining mechanical milling and hot pressing was used to produce CD dispersed Cu composites. The Cu matrix powders and CD were mechanically milled at 500 rpm in an Ar atmosphere…
In this paper we report on the synthesis and characterization of new mixtures of achiral liquid crystalline side-chain polymers with their monomers. The samples have a basic structure similar to materials prepared earlier showing antiferroelectric behaviour. They are investigated to study the influence of peculiar dif…
Polycrystalline Al 2 O 3 ceramics doped with Cr (sintered ruby) up to high concentrations (0.66, 0.76 and 0.97 wt%) were fabricated with an extrusion molding process using Al 2 O 3 and Cr 2 O 3 powders. It was found from absorption spectra that a high concentration of Cr ions was optically activated. The fluorescence…
We show that the Barkhausen avalanches exhibit power law distributions and scaling exponents belonging to two distinct universality classes. We explain these results in terms of the critical behavior of the domain wall at the depinning transition, with exponents set by the long-range dipolar interactions arising from…
This paper investigates inter-bubble gas diffusion in two-dimensional (2D) and three-dimensional (3D) wet foams using the bubble dynamics model. The bubble dynamics model avoids the need to consider T1 type bubble rearrangement events in three dimensions explicitly. Foam bubbles are approximated as overlapping paralle…
The internal friction Q–1 and the square of vibration frequency f2 (proportional to shear modulus G) were measured as functions of temperature on undoped Pb(Zr0.7Ti0.3)O3 (PZT73) and Pb(Zr0.3Ti0.7)O3 (PZT37) ceramics from 20 to 500 °C. Experiments were performed on an inverted torsion pendulum at low frequencies (0.1…
Simultaneous dielectric permittivity measurements and analysis of the first and the second harmonic electro-optical responses have been performed on a 26 mum thick planar oriented sample of the antiferroelectric liquid crystal tolane C8, which has a polymorphism similar to that of MHPOBC. Comparison of these measureme…
In this study, we investigated the reactivity of chromium, iron, and surface-treated 304L stainless steels (SS) toward molecules representing model epoxy resins. These molecules were ammonia (a basic probe molecule also representative of the hardener amine group), 1,2-epoxybutane (for epoxy groups) and 2(methylamino)e…
Abstract The effect of SO2 on activity for NO reduction by methanol over Ag/Al2O3 in the presence of excess oxygen has been investigated. Selective catalytic reduction activity was not decreased but increased and most effective NO reduction temperature shifted from 200-250 °C to 300-350 °C by pre-sulfated Ag/Al2O3 or…
X-ray Photoelectron spectroscopy (XPS) was used to detect major changes to the surface chemistry of polypropylene (PP), high density polyethylene (HDPE) and styrene-butadiene block copolymer (SBS) caused by electrochemical treatment using dilute nitric acid as electrolyte. Large increases in adhesion levels were obser…
We studied by lattice simulation the surface diffusion and relaxation of isolated, self-avoiding polymers partially adsorbed onto a flat surface. The key parameters describing the system are the number of segments in the chain, N, the adsorption energy of a segment, expressed as a dimensionless surface temperature Ts,…
The long-term comfort and durability properties of the flexible molded foams used in many forms of transportation seating are a subject of increasing interest to foam molders and seat producers. Existing and proposed new specifications for load bearing and other fatigue losses have necessitated a new look at the funda…
D.C. conductivity of the ferroelectric BaHPO4 is measured and is found to lie between usual conductivities of semiconductor and insulator. Its temperature dependence shows intrinsic conduction in defective crystals due to H+ ions. The a.c. conductivity calculated from the measured dielectric constant follows σ˜ω1.54,…