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The age hardening and the microstructure of dilute Al-Er-Zr alloys were investigated by microhardness tests and TEM. The Al-0.04Er alloy shows a conventional age hardening behavior and obtains a maximum hardness of 410 MPa after aging for 2 h at 523 K (250 °C) due to precipitation of Al 3 Er. The addition of Zr to Al-Er alloy can slow down the growth of the precipitates and make the age hardening effect remain for a long time in Al-0.04Er-0.04Zr alloy. Addition of Zr retards the decomposition of Al-Er and the Al-0.04Er-0.08Zr alloy can reach higher peak hardness than that of Al-0.04Er after aging for long time at elevated temperature. The precipitation behavior of Al-Er-Zr system is likely to be a new commercial way to developing creep-resistant aluminum alloy.

The microstructure, hardness, elastic modulus, and indentation creep of Ag/Cu multilayers prepared by magnetron sputtering were investigated by x-ray diffraction, transmission electron microscopy, and nanoindentation. The hardness values obey the Hall–Petch relationship as the periodicity decreases to 20 nm. For multilayers with periodicity smaller than 20 nm, the Hall–Petch relationship breaks down and the hardness values saturate at about 4.6 GPa; moreover, there are shear bands formed around their indents and strain bursts occurring during the load-holding process of indentation creep. These results imply that there is a transition of the deformation mechanism in the region where the periodicity is equal to 20 nm. This transition of the deformation mechanism can be ascribed to grain-size-dependent competition between the dislocations-mediated plasticity and grain-boundary sliding-mediated plasticity.

In this work, we have prepared a novel laminated bimodal structure with layer-by-layer distribution of α p and α s phase in high temperature titanium alloy by α+β phase rolling and aging treatment. The lamellar bimodal microstructure is comprised of long-primary α p and secondary α s phase in the Ti-6.0Al-3Sn-5Zr-0.5Mo-1.0Nb-1.0Ta-0.4Si-0.2Er alloy. During α+β phase rolling at 990 °C, the primary α p grain deformed to elongated layer structure, while the lamella secondary α s deformed to kinked and broken chaos morphology. After 800 °C for 1h stabilization and 700 °C for 5h aging treatment, the thickness of the elongated α p layer slightly grew, while the kinked and broken α s were recovered and partially recrystallized to form a layered fine grain structure. The lamellar bimodal microstructure, i.e., elongated primary α p with layered bimodal α s phase has enhanced strength and ductility of the high temperature titanium alloy. This enhanced strength and toughness is mainly attributed to the lamellae α p structure and layered fine α s grain formed by hot rolling and aging treatment.

The purpose of this investigation is to study the effect of roll bending deformation on the microstructure and texture in an Al-Li alloy with different extrusion aspect ratios. The results indicated that the substructure of most extruded fiber grains is not completely eliminated on the ND-ED section at position B with a low extrusion aspect ratio. However, the texture type of the ND-TD section changes from a single texture to an adjacent texture after roll-bending deformation, and the texture intensity decreases from 8.3 to 6.1. With the increase of the extrusion aspect ratio, the effect of roll-bending deformation on the microstructure began to be obvious, especially at position C. A large number of elongated recrystallized grains along the ED direction were transformed into approximately equiaxed grains on ND-ED section after the roll-bending deformation. There were also a small number of approximately equiaxed cell structures. The relative frequency of the low-angle grain boundary rose slightly from 42.1% to 46.7%. The single texture moved to the adjacent texture, and the texture strength increased from 4.8 to 6.3.

Removal efficiency of indicator and pathogenic microorganisms in constructed wetlands were analyzed, and microorganisms removal function performed by copepods was determined. The results showed that the constructed wetlands effectively reduced Escherichia coli, fecal streptococci, total coliforms, and fecal coliforms, the Salmonella spp. removal efficiency was relatively low and the Clostridium perfringens removal was the least. At copepods concentrations of 3.0 x 10²/L, and 6.0 x 10²/L, high die-off rates were observed for indicator and pathogenic microorganisms compared to the control group, and indicator and pathogenic microorganisms in samples with higher concentration of copepods decreased much more rapidly than those in samples with lower concentration. These results suggest that predation by copepods is an important mechanism for the removal of bacteria in constructed wetlands.

Though immensely successful, the standard model of particle physics does not offer any explanation as to why our Universe contains so much more matter than antimatter. A key to a dynamically generated matter–antimatter asymmetry is the existence of processes that violate the combined charge conjugation and parity (CP) symmetry 1 . As such, precision tests of CP symmetry may be used to search for physics beyond the standard model. However, hadrons decay through an interplay of strong and weak processes, quantified in terms of relative phases between the amplitudes. Although previous experiments constructed CP observables that depend on both strong and weak phases, we present an approach where sequential two-body decays of entangled multi-strange baryon–antibaryon pairs provide a separation between these phases. Our method, exploiting spin entanglement between the double-strange Ξ − baryon and its antiparticle 2 Ξ ¯ + , has enabled a direct determination of the weak-phase difference, ( ξ P  −  ξ S ) = (1.2 ± 3.4 ± 0.8) × 10 −2  rad. Furthermore, three independent CP observables can be constructed from our measured parameters. The precision in the estimated parameters for a given data sample size is several orders of magnitude greater than achieved with previous methods 3 . Finally, we provide an independent measurement of the recently debated Λ decay parameter α Λ (refs.  4 , 5 ). The Λ Λ ¯ asymmetry is in agreement with and compatible in precision to the most precise previous measurement 4 . Using spin-entangled baryon–antibaryon pairs, the BESIII Collaboration reports on high-precision measurements of potential charge conjugation and parity (CP)-symmetry-violating effects in hadrons.

Particles directly produced at electron–positron colliders, such as the J/ψ meson, decay with relatively high probability into a baryon–antibaryon pair1. For spin-1/2 baryons, the pair can have the same or opposite helicites. A non-vanishing phase ΔΦ between the transition amplitudes to these helicity states results in a transverse polarization of the baryons2–4. From the joint angular distribution of the decay products of the baryons, this phase as well as the parameters characterizing the baryon and the antibaryon decays can be determined. Here, we report the measurement of ΔΦ = 42.4 ± 0.6 ± 0.5° using Λ → pπ− and Λ¯→p¯π+,n¯π0 decays at BESIII. We find a value for the Λ → pπ− decay parameter of α− = 0.750 ± 0.009 ± 0.004, 17 ± 3% higher than the current world average, which has been used as input for all Λ polarization measurements since 19785,6. For Λ¯→p¯π+ we find α+ = −0.758 ± 0.010 ± 0.007, giving ACP = (α− + α+)/(α− − α+) = −0.006 ± 0.012 ± 0.007, a precise direct test of charge–parity symmetry (CP) violation in Λ decays.The decay asymmetry and helicity phase of polarized baryon–antibaryon pairs are measured at the BESIII experiment, testing charge–parity symmetry and revealing a discrepancy of the Λ → pπ− decay asymmetry with respect to the current world average.

The complicated structure of the neutron cannot be calculated using first-principles calculations due to the large colour charge of quarks and the self-interaction of gluons. Its simplest structure observables are the electromagnetic form factors1, which probe our understanding of the strong interaction. Until now, a small amount of data has been available for the determination of the neutron structure from the time-like kinematical range. Here we present measurements of the Born cross section of electron–positron annihilation reactions into a neutron and anti-neutron pair, and determine the neutron’s effective form factor. The data were recorded with the BESIII experiment at centre-of-mass energies between 2.00 and 3.08 GeV using an integrated luminosity of 647.9 pb−1. Our results improve the statistics on the neutron form factor by more than a factor of 60 over previous measurements, demonstrating that the neutron form factor data from annihilation in the time-like regime is on par with that from electron scattering experiments. The effective form factor of the neutron shows a periodic behaviour, similar to earlier observations of the proton form factor. Future works—both theoretical and experimental—will help illuminate the origin of this oscillation of the electromagnetic structure observables of the nucleon.Form factors encode the structure of nucleons. Measurements from electron–positron annihilation at BESIII reveal an oscillating behaviour of the neutron electromagnetic form factor, and clarify a long-standing photon–nucleon interaction puzzle.

People with severe traumatic brain injury (TBI) experience lifelong sequelae that affect physical, cognitive, and mental health. In other populations, yoga has shown potential to alleviate insomnia, pain, and depression and to improve cognition. The study intended to investigate the feasibility of a six-week, group-yoga intervention for adults with severe chronic TBI, focusing on sleep, pain, mood, and executive function. The research team performed a feasibility study using a mixed-methods, case-series design. The study recruited participants by distributing flyers to local communities and TBI support groups. Participants were two people with severe, chronic, TBI. The intervention was a six-week course of group yoga, with 70-minute classes twice a week. The study assessed outcomes at baseline and postintervention using validated measures to assess executive function, mood, sleep, and pain: the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A), Beck Depression Inventory (BDI), Pittsburgh Sleep Quality Index (PSQI), and Neuropathic Pain Scale (NPS). A semistructured interview was conducted during the week postintervention to obtain qualitative data. The study had a 100% retention rate, a 91.67% attendance rate, and high satisfaction. One participant demonstrated improvement in all outcomes, while the other showed mixed results. Depression showed the most consistent improvement, 47.2% on average. For insomnia, one participant showed improved sleep at 14.29%. The qualitative data demonstrated positive changes in cognition, mood, sleep, and pain. A six-week group yoga intervention is feasible and appears to be beneficial in alleviating symptoms, especially depression and insomnia, in people with severe chronic TBI. A longer intervention period was suggested by the participants.

A bstract With data samples collected with the BESIII detector at seven energy points at s = 3 . 68 − 3 . 71 GeV, corresponding to an integrated luminosity of 333 pb − 1 , we present a study of the Λ transverse polarization in the e + e − → Λ Λ ¯ reaction. The significance of polarization by combining the seven energy points is found to be 2.6 σ including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the Λ Λ ¯ helicity states. The modulus ratio and the relative phase of EM- psionic form factors combined with all energy points are measured to be R Ψ = 0.71 − 0.10 + 0.10 ± 0.03 and ∆Φ Ψ = 23 − 8.0 + 8.8 ± 1.6 ° , where the first uncertainties are statistical and the second systematic.