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[en] Rare earth impurities in high-purity Gd2O3 have been determined by ICP-OES. HREE except Ho were analysed by directly nebulising 1 mg/ml of the matrix solution and the LREE were analysed after separation on an anion-exchange Dowex 1 x 8 resin. The recovery studies show nearly 100% separation. The determination of 30 ppm of HREE in gadolinium oxide is possible. (orig.)
[en] Detailed magnetic and transport properties of orthorhombic perovskites ceramics Gd_1_-_xCa_xCrO_3 (x=0.0-0.3) have been reported. Magnetization measurements under in both field cooled cooling (FCC) and field cooled heating (FCH) protocol reveal magnetization reversal at low temperatures and low magnetic field. This indicates clear evidence of two magnetic sublattices aligned opposite to each other. The effect of Gd"3"+ ion on the low temperature magnetization decreases largely above x=0.2. The dc magnetic susceptibility (χ) was Curie-Weiss-like above the transition temperature (T _m_a_x) with an effective magnetic moment (μ_e_f_f) that decreased with the increase of Ca concentration. These orthochromites exhibit a temperature independent, large and positive thermoelectric power or Seebeck coefficient (S) value above 200 K. Upon Ca"2"+ substitution, a concomitant decrease of the S value is found
[en] The influence of magnetic field cycling through the first-order magnetostructural transformation on the magnetic and magnetocaloric properties, as well as hysteresis of polycrystalline Gd5Si2Ge2, has been studied using magnetometry. Here, the cycling has a minimal effect on the magnetic field-induced entropy change and the phase transformation temperature of the material. On the other hand, magnetic hysteresis decreases by 30% after approximately ten cycles and remains low unless the sample is moved far into the paramagnetic regime. Factors playing a role in the history dependence of hysteresis have been discussed.
[en] Fabrication of neutron absorbing glass containing silicon, aluminium, oxygen and/or nitrogen and gadolinium is described. Gadolinium oxide content is 10-30 molar per cent
[fr]On decrit le procede de fabrication de verre neutrophage contenant du silicium, de l'aluminium, de l'oxygene et/ou de l'azote et du gadolinium. La teneur en oxyde de gadolinium est de l'ordre de 10 a 30% molaire
[en] This paper examines the causal relationship between the per capita energy consumption and the per capita GDP in a panel of 11 selected oil exporting countries by using panel unit-root tests and panel cointegration analysis. The results show a unidirectional strong causality from economic growth to energy consumption for the oil exporting countries. The findings have practical policy implications for decision makers in the area of macroeconomic planning. In most major oil exporting countries, government policies keep domestic prices bellow free market level, resulting in high levels of domestic energy consumption. The results imply that the energy conservation through reforming energy price policies has no damaging repercussions on economic growth for this group of countries. (author)
[en] Patterned arrays of epitaxial GaN (0001) nanorods by Si-ion bombardment of Si (111) substrates have been fabricated for the field emitters. The field emission characteristics of the GaN nanorod arrays were measured; both GaN nanorods on self-implanted and GaN matrix on unimplanted Si substrates. The current densities as high as 10 mA/cm2 have been observed for GaN nanorod arrays under applied electrical field of about 70 V/μm, while the stability of field emission at 3.93 mA/cm2 has been tested up to 7 hours with the standard deviation of 0.2%.
[en] Hydrophobic polymer mixed with Gd2O3 can be used in nuclear industry as a neutron shield because of its neutron attenuating and absorbing property, while it was reported that the smaller particles dispersed polymer composites can enhance radiation shielding efficiency compared to larger particles dispersed ones. However, preparations of such materials are difficult because of the poor dispersion of the fine particles in the polymer matrix. Surface modification of the nanoparticles is therefore required for the homogeneous dispersion of the particles in the polymer matrix. In this study, pulverization of the micro-Gd2O3 particles and simultaneous surface coating of the nanoparticles by polymeric surfactant low density polyethylene (LDPE) were performed by using one-step of high energy wet ball-mill. Dispersion and neutron shielding effect of the nano- and micro-Gd2O3 fillers in mixed polymer of ethylene propylene monomer (EPM) and high density polyethylene (HDPE) were examined