46,944 research outputs found
Prediction of a new efficient permanent magnet SmCoNiFe3
We propose a new efficient permanent magnet, SmCoNiFe3, that is a
breakthrough development of the well-known SmCo5 prototype. More modern
neodymium magnets of the Nd-Fe-B type have an advantage over SmCo5 because of
their greater maximum energy products due to their iron-rich stoichiometry. Our
new magnet, however, removes most of this disadvantage of SmCo5 while
preserving its superior high-temperature efficiency over the neodymium magnets
Antarctic climate, Southern Ocean circulation patterns, and deep water formation during the Eocene
We assess early-to-middle Eocene seawater neodymium (Nd) isotope records from seven Southern Ocean deep-sea drill sites to evaluate the role of Southern Ocean circulation in long-term Cenozoic climate change. Our study sites are strategically located on either side of the Tasman Gateway and are positioned at a range of shallow (Nd(t) = −9.3 ± 1.5). IODP Site U1356 off the coast of Adélie Land, a locus of modern-day Antarctic Bottom Water production, is identified as a site of persistent deep water formation from the early Eocene to the Oligocene. East of the Tasman Gateway an additional local source of intermediate/deep water formation is inferred at ODP Site 277 in the SW Pacific Ocean (εNd(t) = −8.7 ± 1.5). Antarctic-proximal shelf sites (ODP Site 1171 and Site U1356) reveal a pronounced erosional event between 49 and 48 Ma, manifested by ~2 εNd unit negative excursions in seawater chemistry toward the composition of bulk sediments at these sites. This erosional event coincides with the termination of peak global warmth following the Early Eocene Climatic Optimum and is associated with documented cooling across the study region and increased export of Antarctic deep waters, highlighting the complexity and importance of Southern Ocean circulation in the greenhouse climate of the Eocene
Assessing the critical material constraints on low carbon infrastructure transitions
We present an assessment method to analyze whether the disruption in supply of a group of materials endangers the transition to low-carbon infrastructure. We define criticality as the combination of the potential for supply disruption and the exposure of the system of interest to that disruption. Low-carbon energy depends on multiple technologies comprised of a multitude of materials of varying criticality. Our methodology allows us to assess the simultaneous potential for supply disruption of a range of materials. Generating a specific target level of low-carbon energy implies a dynamic roll-out of technology at a specific scale. Our approach is correspondingly dynamic, and monitors the change in criticality during the transition towards a low-carbon energy goal. It is thus not limited to the quantification of criticality of a particular material at a particular point in time. We apply our method to criticality in the proposed UK energy transition as a demonstration, with a focus on neodymium use in electric vehicles. Although we anticipate that the supply disruption of neodymium will decrease, our results show the criticality of low carbon energy generation increases, as a result of increasing exposure to neodymium-reliant technologies. We present a number of potential responses to reduce the criticality through a reduction in supply disruption potential of the exposure of the UK to that disruption
Infrared organic light emitting diodes using neodymium tris-(8-hydroxyquinoline)
Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 88, 777 (2000) and may be found at
Self-induced spin glass state in elemental and crystalline neodymium
Spin glasses are a highly complex magnetic state of matter, intricately
linked to spin frustration and structural disorder. They exhibit no long-range
order and exude aging phenomena, distinguishing them from quantum spin liquids.
We report a new type of spin glass state, the spin-Q glass, observable in
bulk-like crystalline metallic neodymium thick films. Using spin-polarized
scanning tunneling microscopy combined with ab initio calculations and
atomistic spin-dynamics simulations, we visualize the variations in
atomic-scale non-collinear order and its response to magnetic field and
temperature. We quantify the aging phenomena relating the glassiness to
crystalline symmetry and the energy landscape. This result not only resolves
the long-standing debate of the magnetism of neodymium, but also suggests that
glassiness may arise in other magnetic solids lacking extrinsic disorder
Photocatalytic activity, optical and ferroelectric properties of Bi0.8Nd0.2FeO3 nanoparticles synthesized by sol-gel and hydrothermal methods
In this study, the effects of synthesis method and dopant Neodymium ion on
the ferroelectric properties and photocatalytic activity of bismuth ferrite
were studied. BiFeO3 (BFO) and Bi0.8Nd0.2FeO3 (BNFO) nanoparticles were
prepared through a facile sol-gel combustion (SG) and hydrothermal (HT)
methods. The as-prepared products were characterized by X-ray powder
diffraction (XRD), Furrier transform infrared spectroscopy (FTIR) and
transmission electron microscope (TEM) images. Both nanophotocatalysts have
similar crystal structures, but the SG products have semi-spherical morphology.
On the other hand, HT samples have rod-like morphology. TEM results indicated
that the morphology of products was not affected by the doping process. The
thermal, optical and magnetic properties of nanoparticles were investigated by
thermogravitometry and differential thermal analysis (TG/DTA), UV-vis
spectroscopy, and vibrating sample magnetometer (VSM). The ferroelectric
properties of BNFO nanoparticles were improved compared to the undoped bismuth
ferrite. The photocatalytic activity of as-synthesized nanoparticles was also
evaluated by the degradation of methyl orange (MO) under visible light
irradiation. The photocatalytic activity of nanoparticles prepared via sol-gel
method exhibited a higher photocatalytic activity compared to powders obtained
by hydrothermal method. Also substitution of Nd into the BFO structure
increased the photocatalytic activity of products
Collectivity in Heavy Nuclei in the Shell Model Monte Carlo Approach
The microscopic description of collectivity in heavy nuclei in the framework
of the configuration-interaction shell model has been a major challenge. The
size of the model space required for the description of heavy nuclei prohibits
the use of conventional diagonalization methods. We have overcome this
difficulty by using the shell model Monte Carlo (SMMC) method, which can treat
model spaces that are many orders of magnitude larger than those that can be
treated by conventional methods. We identify a thermal observable that can
distinguish between vibrational and rotational collectivity and use it to
describe the crossover from vibrational to rotational collectivity in families
of even-even rare-earth isotopes. We calculate the state densities in these
nuclei and find them to be in close agreement with experimental data. We also
calculate the collective enhancement factors of the corresponding level
densities and find that their decay with excitation energy is correlated with
the pairing and shape phase transitions.Comment: 6 pages, 3 figures, to be published in the Proceedings of the Fourth
International Workshop on Compound-Nuclear Reactions and Related Topics
(CNR*13
YAG:Nd crystals as possible detector to search for double beta and alpha decay of neodymium
Energy resolution, alpha/beta ratio, pulse-shape discrimination for gamma
rays and alpha particles, radioactive contamination were studied with neodymium
doped yttrium-aluminum garnet (YAG:Nd). Applicability of YAG:Nd scintillators
to search for double beta decay and alpha activity of natural neodymium
isotopes are discussed.Comment: 10 pages, 4 fig
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