Nd2O3 : Eu3+ nanocrystalline phosphor–a new potential thermoluminescing material for dosimetry

Nanoparticles of trivalent Eu³⁺-doped Nd₂O₃ phosphors have been prepared using a low-temperature solution combustion method with metal nitrate as precursor and oxalyldihydrazide as a fuel at a fairly low temperature (<500°C) and in a very short time (<5 min). A powder X-ray diffraction pattern reveals that cubic Nd₂O₃ : Eu³⁺ crystallites are directly obtained without the requirement of further calcinations. The crystallite size, evaluated from Scherer's formula, was found to be in the range of 20–30 nm. The microstructure and morphology were studied by scanning electron microscopy, which showed the phosphor to be foamy and fluffy in nature. Thermoluminescence characteristics of the Nd₂O₃ : Eu³⁺ have been studied using gamma irradiation. These demonstrate that the phosphor is suitable for use as a dosimeter.     

Nanoindentation-induced elastic–plastic transition and size effect in α-Al2O3(0001)

The mechanical properties of α-Al₂O₃(0001) have been investigated using the technique of nanoindentation with a Berkovich indenter. Coupled with the Hertzian contact theory, a theoretical shear strength of 28?±?2?GPa was determined from the onset of pop-in events on load–displacement curves during loading, and the intrinsic hardness 30?±?3?GPa was obtained by analysis of the so-called indentation size effect, based on the concept of geometrically necessary dislocations. The predicted values of the shear strength, hardness and elastic modulus are in good agreement with available experimental data. The importance of experimentally calibrating the area function over the contact depth range prior to nanoindentation tests is emphasized.     

Giant electrocaloric effect of highly (1 0 0)-oriented 0.68PbMg1/3Nb2/3O3–0.32PbTiO3 thin film

PbZr_0.95Ti_0.05O₃ thin film has the highest electrocaloric properties of all the oxide thin films (0.48?K?V^?1). Here, it is shown giant electrocaloric properties in 200?nm (1?0?0)-oriented PMN–PT 68/32 film near the ferroelectric Curie temperature of 146?°C. The results indicate the significance of this system to achieve electrocaloric entropy change and temperature change, up to 32.21?J/kg?°C and 14?K, respectively, in 12?V (i.e. 1.155?K?V^?1) near the Curie point. This exceeds the previous best results obtained in PbZr_0.95Ti_0.05O₃ thin film.     

Formation of self-assembled Cu-γ-Al 2 O 3 nanocomposite

We report here the formation of a novel 'self-assembled' three-dimensional nanocomposite consisting of uniformly sized, evenly spaced spherical Cu nanoparticles embedded within a polycrystalline n -Al 2 O 3 matrix. This was discovered serendipitously during the examination of an ion-beam-milled ZrO 2 specimen in a transmission electron microscope. This nanocomposite was deposited as a coating during ion-beam milling by the co-sputtering of Cu and Al from the ion-mill hardware in the presence of O. The mechanism by which this highly organized nanocomposite forms is discussed, together with broader implications of these types of metal-ceramic nanocomposite and the possibility of using sputter deposition as a generic method for making them.     

Crystal structure of 1–2–3 superconductor precursor material: Vacancy distribution and lattice relaxation

Abstract

The crystal structure of tetragonal YBa₂Cu₃O_7-δ, with δ close to the critical composition for the tetragonal–orthorhombic transition, has been refined. The oxygen deficiency δ = 0·65(10) is accommodated by both the O(1) and O(2) sites which coordinate the ‘square planar’ Cu(1) site. Structural relaxation around the vacancies is indicated by large anisotropic Debye-Waller ellipsoids in the structural layer formed by these atomic sites. The Y, Ba, Cu(2) and O(3) sites are not involved in the relaxation mechanism. On comparing this structure with the δ ≈ 0 and δ ≈ 1 end-members, we find that with decreasing oxygen content of the structure the Cu(2) valence type transforms from square-pyramidal character towards square-planar character. This effect gives the main contribution to the increase of the c ₀ lattice constant with decreasing oxygen content.     

Formation of Al3Ni2-type nanocrystalline τ 3 phases in the Al–Cu–Ni system by mechanical alloying

An elemental powder mixture of Al (70 at.%), Ni (15 at.%) and Cu (15 at.%) was milled in a high-energy ball mill for various times ranging from 10 to 100?h to form ternary intermetallic alloys. X-ray diffraction and transmission electron microscopy techniques were employed for characterization of the samples. The dissolution of the individual elements into an alloy led to the formation of a τ₃ vacancy-ordered phase after 100?h of milling. This phase was found to be quite stable against milling, and no other crystalline and amorphous phases could be detected. The powder after 100?h of milling was found to contain mostly τ₃ nanophases with partial ordering, and with crystallite sizes in the range 10–20?nm along with a lattice strain of ～0.675%. The milled powder, after annealing at 700°C for 20, 40 and 60?h, revealed the formation of a strain-free and ordered τ₃ phase with a crystallite size of 80?nm, indicating grain coarsening. It is interesting to note that the mechanical energy imparted during milling could not completely destroy the vacancy ordering in the τ₃ phase, unlike other stoichiometric Al–Cu–transition metal (TM) systems, where the disordered B2 (bcc) phase is commonly observed instead of any vacancy-ordered phases.     

Stress-corrosion cracking in YBa2Cu3O7−x ceramic superconductor

Abstract

Thin-foil transmission electron microscopy specimens of orthorhombic YBa²Cu³O^7?x subjected to residual elastic strains have shown slow crack growth in an atmosphere with low moisture content. Microcracks, initiated by amorphization at the strained edges, propagate alternately along (110) twin boundaries and (001) stacking faults, where strain energy is accumulated locally. The formation of carbon-rich amorphous layers along the strained lattice planes, followed by residual stress-assisted crack propagation, resembles stress-corrosion cracking in this ceramic superconductor.     

Interrelated emission and spin–spin relaxation feature mediated by VO+ defects in Gd2O3 nanorods subjected to swift ion impact

We report on the manifestation and interconnected photoluminescence and electron paramagnetic resonance responses in gadolinium oxide (Gd₂O₃) nanorods subjected to 80 MeV carbon ion irradiation. On increasing the irradiation fluence between 1 × 10¹¹ and 3 × 10¹² ions/cm², the emission associated with neutral oxygen vacancies (V_Ox), positioned at ~350 nm, undergoes a steady increase compared to that associated with singly charged vacancies (V_O⁺), located at ~414 nm. The enhancement of spin–spin relaxation time (τ_ss) is ascribed to a substantial changeover from V_O⁺ to V_Ox defects with irradiation, the former being recognized as the major contributor to paramagnetic centres. Interconnected luminescence and spin–spin relaxation could provide insight for making advanced nanophosphors and spin valve elements.     

The MMPI–2 Restructured Form Personality Psychopathology Five Scales: Bridging DSM–5 Section 2 Personality Disorders and DSM–5 Section 3 Personality Trait Dimensions

This study examined in a college sample and a sample of non-treatment-seeking, trauma-exposed veterans the association between the MMPI–2 Restructured Form (MMPI–2–RF) Personality Psychopathology Five (PSY–5) Scales and DSM–5 Section 2 personality disorder (PD) criteria, the same system used in DSM–IV–TR, and the proposed broad personality trait dimensions contained in Section 3 of DSM–5. DSM–5 Section 2 PD symptoms were assessed using the SCID–II–PQ, and applying a replicated rational selection procedure to the SCID–II–PQ item pool, proxies for the DSM–5 Section 3 dimensions and select facets were constructed. The MMPI–2–RF PSY–5 scales demonstrated appropriate convergent and discriminant associations with both Section 2 PDs and Section 3 dimensions in both samples. These findings suggest the MMPI–2–RF PSY–5 scales can serve both conceptually and practically as a bridge between the DSM–5 Section 2 PD criteria and the DSM–5 Section 3 personality features.     

Kinetic study of static recrystallization in an Fe–Al–O ultra-fine-grained nanocomposite

A nearly abrupt coarsening of grains is observed in a newly developed Fe–Al–O ultra-fine-grained nanocomposite with a significant volume fraction (4%) of alumina nano-precipitates. The microstructure of the alloy was analysed in different states (as-received and annealed) by means of scanning electron microscopy, transmission electron microscopy (TEM) and hardness. The initial grain size 150–200 nm increases up to 50 μm during annealing 1000 °C/8 h and thereafter demonstrates saturation. A linear correlation between volume fraction of coarse grains and hardness was found. It was identified by TEM that alumina nano-precipitates stabilize the dislocation microstructure against recovery very effectively and the grain coarsening is due to fast growth of very few dislocation free grains. Thus, the observed grain coarsening has the attributes of static recrystallization.     

Obituary: Gillian O. Howie, 1965–2013

The present special issue of Sophia on ‘feminist philosophy of religion’ is dedicated to Gillian O. Howie who died in 2013. This essay is a short obituary touching on Howie’s philosophical and personal legacy. The intention is to give a brief overview of Howie as a courageous woman with boundless intellectual curiosity and passionate commitments to feminist activities; these include writing and living her philosophical vision for creating a just society with collective political action. Howie inspired both women and men in philosophy—especially, but not only, feminist philosophers of religion—with her work on the critical role of sexual difference in life today.     

Precipitation in a Cu–4Ti–2Be alloy

It is known that the binary Cu–2?wt.% Be alloy can be strengthened by ageing its supersaturated solution at 523?K. The increase in the strength arising from ageing is because of the formation of GP zones. The same level of strength is achieved by ageing the supersaturated solid solution of a dilute binary Cu–4?wt.% Ti alloy at 723?K. In contrast to Cu–2?wt.% Be alloy, the increase in strength in this alloy occurs on account of spinodal decomposition of the as-quenched microstructure through the mechanism of clustering and ordering. In the present study, decomposition of a supersaturated solid solution of the ternary Cu–4?wt.% Ti–2?wt.% Be alloy was studied. Whereas ageing of this alloy at 523?K resulted in the formation of GP zones like in a Cu–2?wt.% Be alloy, ageing at 723?K resulted in a spinodally decomposed microstructure as in a Cu–4?wt.% Ti alloy. The decomposition of the ternary alloy at the two temperatures by two different mechanisms indicates that Be and Ti in solution in Cu act, more or less, independently of each other during ageing.     

Mapping the MMPI–2/MMPI–2–RF Restructured Clinical Scales Onto Mood Markers in an Israeli Sample

This study cross-culturally evaluated the Minnesota Multiphasic Personality Inventory–2/MMPI–2 Restructured Form (MMPI–2/MMPI–2–RF) emotion-focused Restructured Clinical (RC) Scales to examine whether their patterns of associations with positive affect (PA) and negative affect (NA) are as expected based on Tellegen, Watson, and Clark's (1999a Tellegen, A., Watson, D., &; Clark, L. A. (1999a). Further support for a hierarchical model of affect. Psychological Science, 10, 307–309.[Crossref], [Web of Science ®] , [Google Scholar], 1999b Tellegen, A., Watson, D., &; Clark, L. A. (1999b). On the dimensional and hierarchical structure of affect. Psychological Science, 10, 297–303.[Crossref], [Web of Science ®] , [Google Scholar]) mood model. The sample was composed of 100 men and 133 women from psychiatric settings in Israel who completed the MMPI–2 and the Mood Check List (MCL; Zevon &; Tellegen, 1982 Zevon, M. A., &; Tellegen, A. (1982). The structure of mood change: An idiographic/nomothetic analysis. Journal of Personality and Social Psychology, 43, 111–122.[Crossref], [Web of Science ®] , [Google Scholar]). Results indicated that RCd was substantially correlated with both PA and NA in opposite directions, and that RC2 and RC7 were more highly correlated with PA and NA, respectively. Further, when compared with their Clinical Scale counterparts, RC2 and RC7 exhibited comparable convergent validities and improved discriminant properties. Findings provide support for Tellegen et al.'s (2003 Tellegen, A., Ben-Porath, Y. S., McNulty, J. L., Arbisi, P. A., Graham, J. R., &; Kaemmer, B. (2003). MMPI–2 Restructured Clinical (RC) scales: Development, validation, and interpretation. Minneapolis: University of Minnesota Press. [Google Scholar]) goal to link the RC scales to contemporary conceptualizations of mood.     

Investigations of the optical and EPR spectra for VO2+ in NaHC2O4 · H2O single crystals

Theoretical calculations of the optical absorption and electron paramagnetic resonance (EPR) spectra of VO²⁺ in NaHC₂O₄?·?H₂O single crystals were performed using the complete diagonalization energy matrix method (CDM) and the perturbation theory method (PTM) for the 3d ¹ electronic configuration. The calculated results are in good agreement with experimental results. The negative signs of hyperfine structure constants A _∥ and A _⊥ for VO²⁺ in NaHC₂O₄·H₂O single crystals are suggested from the calculations. Comparison of the two calculation methods indicates that the PTM is a good approximation of CDM and that both theoretical methods are valid in interpretation of the optical and EPR spectra for VO²⁺ ions in NaHC₂O₄?·?H₂O crystals.