Materials Literature
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Chilled samples of base iron and magnesium-treated iron were surveyed using optical microscopy, SEM and computer assisted microanalysis. Numerous voids, 0.5–1 m m in size, were observed in magnesiumcontaining chilled samples. Graphite spheroids at an early stage of growth, 3–5 m m in size, and inclusions were also obs…
Curie temperatures are evaluated using first principles in (K,Zr) 2 S and (K,Nb) 2 S diluted magnetic semiconductors which have been designed as half-metallic and transparent materials with a large magnetoptical effect. From the total energy differences between the ferromagnetic state and the spin-glass state, estimat…
Abstract Summary: A hard‐segment homopolymer (HSH) and segmented poly(ester urethanes) (PESU) were studied by TEM to estimate their stability against electron‐beam irradiation. The bright‐field image and electron‐diffraction modes in TEM and optical polarised microscopy were used. It is shown that both soft and hard s…
In order to recycle the abandoned Nd–Fe–B sintered magnets, we attempted to develop a high coercive magnetic powder for bonded magnets from the Nd–Fe–B sintered magnet scraps. It was found that the coercivity of the powders obtained from the Nd–Fe–B sintered magnet scraps could be fully recovered by the thermally acti…
Dielectric properties of polycrystalline CaCu/sub 3/Ti/sub 4/O/sub 12/ (CCTO) pellets sintered in the temperature range 1000-1200/spl deg/C were evaluated with impedance spectroscopy at frequency range of 10/sup 2/ to 10/sup 7/ Hz from 90 K to 294 K. A correlation has been established between the pair values of low fr…
Nous avons resolu la structure cristalline de la turanite, Cu 2 + 5 (V 5 + O 4 ) 2 (OH) 4 , provenant de la localite type, le gisement de Ra-U de Tyuya-Muyun, cretes d'Alai, district de Osh, au Kyrgyzstan, triclinique, groupe spatial P1, a 5.3834(2), b 6.2736(3), c 6.8454(3) A, α 86.169(1), β 91.681(1), γ92.425(1)°, V…
On single crystals of austenitic stainless steel with nitrogen C N =0-0.5 wt.% the stages of stress-strain curves, work-hardening coefficient, deformation mechanism - slip and twinning, the developing of dislocation structure in dependence on crystal tensile axis orientation, test temperature, nitrogen concentration h…
Recently, electrical resistivity (ER) measurements have been done during some thermomechanical tests in copper based shape memory alloys (SMA's). In this work, single crystals of Cu-based SMA's have been studied at different temperatures to analyse the relationship between stress (s) and ER changes as a function of th…
Abstract 21,23-Dithiaporphyrins and 21-monothiaporphyrins with propane-1,3-diyldioxy and its derivatives at the β-thiophene carbons were synthesized and characterized. The cyclic substituents introduced at the β-thiophene carbons altered the electronic properties of the porphyrins. The X-ray structure for 2,3-bis(2,2-…
The hierarchical two-layer (H2L) model describes the effective transverse thermal conductivity (keff ) of a two-dimensional (2-D) SiC f /SiC composite plate made from stacked and infiltrated woven fabric layers in terms of constituent properties and microstructural and architectural variables. The H2L model includes t…
The erosion of highly-ordered pyrolytic graphite (HOPG) caused by exposure to hyperthermal atomic 0( 3 P) atoms was explored. Profilometry has revealed that the overall erosion yield is linear with respect to increasing atomic oxygen exposure at a constant sample temperature of 373 K. Atomic force microscopy (AFM) was…
O objetivo do presente trabalho é apresentar a síntese de um poli (ácido âmico) (PAA) a ser utilizado como formador de interfase no processamento de compósitos termoplásticos de alto desempenho. Os materiais compósitos termoplásticos constituídos de um reforço rígido e de uma matriz dúctil têm as suas propriedades mec…
The present paper deals with kinetics of LaCo0 3 .? preparation with La 2 0 3 and Co 3 0 4 powder mixture.
The magnetocaloric effect ΔT ex and the magnetization in La1−x SrxMnO3 single crystals (x=0.1, 0.125, 0.175, 0.3) have been experimentally studied. The magnetic entropy and the magnetocaloric effect ΔT th were computed from magnetization curves. All the samples exhibited a maximum in the ΔT th(T) curve at T=T max ′ .…
Microscopic voids in the die attachment solder layers of power semiconductor devices degrade their overall thermal transfer performance. This paper presents analytical results of the effect of spherical and spheroidal void geometries on the thermal conductivity of bulk media. Analytical results are compared with axial…
Although carbon nanofibers might have wide potentials in applications, most of their physical properties have yet to be investigated. This paper reports on the low-temperature electronic transport properties of an electrospun polyacrylonitrile-based carbon nanofiber, with its mean diameters around 120 nm. The resistan…
In order to investigate the compressive mechanical characteristics of Sm123 single-grain bulk superconductors fabricated by TSMG method, compressive tests in the direction parallel and perpendicular to the c-axis have been carried out by using small specimens cut from the bulk samples. Stress-strain curves in the dire…
Abstract Different substrate mixtures of acetic acid and valeric acid were used to synthesize copolymers of poly([R]‐3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) (PHB/HV) with Paracoccus denitrificans under N‐limited conditions. A correlation between the substrate ratio and HV content was found in batch experiments, whic…
Abstract The effect of pH on the electrochemical behavior of austenitic stainless steels in naturally aerated and nitrogen‐deaerated buffer solutions has been studied. Potentiodynamic and ac impedance techniques were used. The results indicate that corrosion current (I corr ) decreases with pH. By examining the impeda…
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