Knowing when to seek anger: Psychological health and context-sensitive emotional preferences

According to hedonic approaches to psychological health, healthy individuals should pursue pleasant and avoid unpleasant emotions. According to instrumental approaches, however, healthy individuals should pursue useful and avoid harmful emotions, whether pleasant or unpleasant. We sought to reconcile these approaches by distinguishing between preferences for emotions that are aggregated across contexts and preferences for emotions within specific contexts. Across five days, we assessed daily confrontational and collaborative demands and daily preferences for anger and happiness. Somewhat consistent with hedonic approaches, when averaging across contexts, psychologically healthier individuals wanted to feel less anger, but not more happiness. Somewhat consistent with instrumental approaches, when examined within contexts, psychologically healthier individuals wanted to feel angrier in more confrontational contexts, and some wanted to feel happier in more collaborative contexts. Thus, although healthier individuals are motivated to avoid unpleasant emotions over time, they are more motivated to experience them when they are potentially useful.     

Structure of a cubic phase related to Cd?Mg?rare-earth quasicrystals

The structure of a Cd₆₈Mg₁₂Dy₂₀ crystalline phase denoted as the φ-phase, which has a composition close to that of the Cd₆₆Mg₂₁Dy₁₃ icosahedral quasicrystalline phase, has been investigated by electron diffraction and scanning transmission electron microscopy (STEM). The φ phase has a fcc lattice with a = 21.6Å. High-angle annular dark-field STEM with Z contrast confirms that the phase has the Cd₄₅Sm₁₁-type structure. The atomic cluster in the structure is shown to be characterized by a Friauf polyhedron with tetrahedral symmetry.     

Vortex dynamics in La1.86Sr0. 14CuO4 studied by magnetoresistivity

Abstract

Vortex dynamics in La_1.86Sr_0.14CuO₄ have been studied by the measurement of ρ_c ^//i (T, H), where ρ_c ^//i is the c-axis resistivity for H//i (i = c or a-b). We argue that, at temperatures higher than the irreversibility temperature T _irr, the usual vortex picture breaks down owing to the thermal motion of vortices, resulting in a T- and T _in-dependent anisotropic parameter γ. After taking into account the dependence of γ on T and T _irr, we show that at each given temperature we can rescale the ρ_c ^//a-b (T, H) data onto the corresponding ρ_c ^//c (T, H) curves. This scaling property clearly indicates that the Lorentz-force-free mechanism is responsible for ρ_c ^//a-b (T, H). Furthermore, we also show that the measured ρ_c ^//a-b (T, H) data can be explained in terms of the recently developed extended Josephson coupling model which is verified by rescaling ρ_c ^//a-b (T) data for various fields onto a single curve.     

Tension and compression of bulk Al-7.5 wt% Mg alloy

The mechanical behaviour of bulk ultrafine-grained Al-7.5 wt% Mg alloy consolidated from cryomilled powders has been investigated. The experimental data show that the alloy exhibits high strength, low strain hardening, serrated flow and relatively high ductility. In addition, the data indicate that the yield strength in tension is essentially equal to that in compression. The yield and flow strengths of the alloy are discussed in terms of strengthening processes that are related to grain size, the Orowan mechanism and solid-solution hardening. The serrations in the stress-strain curve are discussed in terms of dynamic strain ageing and deformation twinning.     

Microwave-induced heating of a single glassy phase and a two-phase material consisting of a metallic glass and Fe powder

Metallic glasses exhibit low viscosity in a temperature range between the glass transition and the crystallization temperature, a feature that allows successful sintering of glassy powders. Microwave heating, being volumetric, has significant advantages over conventional heating in materials processing, such as substantial energy savings, high heating rates and process cleanliness. In the present study, we investigate the stability of Cu₅₀Zr₄₅Al₅ glassy powders and the formation of a bulk two-component metallic glassy-crystal sample by microwave heating in a single-mode cavity (915 MHz) in an alternating magnetic field.     

Structural evolution during crystal nucleation in supercooled liquids with icosahedral short-range order

The structural evolution during crystal nucleation in supercooled Lennard–Jones liquids at a supercooling of 0.3T _m (T _m is the melting temperature) has been studied by molecular dynamic simulations. The icosahedral clusters are observed to compete with crystalline clusters in space, and rearrange before crystal nucleation. Both the stable face-centered-cubic and hexagonal-close-packed (hcp) structures and metastable body-centered-cubic (bcc) structures nucleate simultaneously, resulting in the formation of an incomplete bcc meso-layer in the nuclei. The nuclei form twinned crystal with five-fold axes through a successive twinning process bounded by planes with hcp atoms.     

First-principles investigation of bowing parameter in zinc-blende ScxGa1−xN

Helium generated in materials by the nuclear reaction (n,?α) is generally considered to be harmful. It is well-known that helium prompts not only the nucleation of interstitial-type dislocation loops, but also the nucleation of voids in metals and alloys irradiated with high-energy particles, which degrades their mechanical properties. In this study, however, we find that helium trapped by dislocations in Ni increases both the ultimate tensile strength and total elongation.     

Structural phase transitions in epitaxial SrRuO3 thin films

The microstructural evolution of epitaxial SrRuO₃ thin films from ambient temperature (about 293K) to about 900K has been studied by in-situ transmission electron microscopy. Upon heating from the ambient temperature, the intensities of h, k, 2n+1 and h, -h+2n+1, 0 reflections in selected-area electron diffraction patterns decrease with increasing temperature. Two structural phase transitions were observed at about 673and about 783K, revealed by the vanishing of the h, k, 2n+1 and h,-h+2n+1, 0 reflections respectively. The examination of electron diffraction patterns along several different zone axes, taking into account the possible tilting configurations of RuO₆ octahedra, indicates that, upon heating, the orthorhombic structure of SrRuO₃ transforms into a tetragonal structure at about 673K, and further transforms into a cubic structure at about 783K. Possible structural models for the high-temperature phases are considered.     

On the orientation relationship between a2 precipitates and the B2 phase in a Ti-47at.%Al-2at.%W-0.5at.%Si alloy

An k -phase Mn-Al-C single crystal was grown and annealed to obtain an intermediate stage of the k M transformation. The crystal was analysed by transmission electron microscopy, and direct evidence for the operation of the shear mode was obtained. The transformation occurs in two steps from the hcp structure ( k ) over the orthorhombic structure ( k ' phase) to the tetragonal phase. The study reveals the morphologies of k ' and , the necessity for reordering during the second transformation step ( k ' M ) which is not a purely martensitic transformation, and the selection of variants which is controlled by stresses through the selection of one k ' variant.     

Formation of ductile Al-based metallic glasses without rare-earth elements

Al₇₅Cu₁₇Mg₈ is a eutectic composition according to the ternary phase diagram, which can be quenched into a fully amorphous phase by adding 2-8at.% Ni, but the addition of a similar percentage of Gd failed to form the amorphous phase. The amorphous alloys obtained exhibit two broad diffuse peaks in the X-ray diffraction curves and, correspondingly, two halo rings in the electron diffraction patterns, implying that two types of local atom configuration exist. Thermal analysis of the amorphous alloys indicates that the primary crystallization peak shifts to higher temperatures with increasing Ni content. The occurrence of a nucleation and crystal growth peak during isothermal crystallization reveals the amorphous nature of the quenched ribbon alloys. The quenched amorphous ribbons do not break after bending by 180°. Mechanical testing yielded a tensile strength of 810MPa for (Al₇₅Cu₁₇Mg₈)₉₅Ni₅, and a vein structure, characteristic of amorphous fracture, is apparent in scanning electron micrographs. The different effects of Ni and Gd on the glass formation indicate that the large atomic size of Gd is not critical to the glass formation.