The great technological potential for bulk metallic glasses (BMGs) arises primarily because of their superior mechanical properties. To realize this potential, it is essential to overcome the severe ...ductility limitations of BMGs which are generally attributed to shear localization and strain softening. Despite much international effort, progress in improving the ductility of BMGs has been limited to certain alloys with specific compositions. Here, we report that severe plastic deformation of a quasi-constrained volume, which prevents brittle materials from fracture during the plastic deformation, can be used to induce strain hardening and to reduce shear localization in BMGs, thereby giving a significant enhancement in their ductility. Structural characterizations reveal the increased free volume and nanoscale heterogeneity induced by severe plastic deformation are responsible for the improved ductility. This finding opens a new and important pathway towards enhanced ductility of BMGs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
12.
Observation of e+e- → γX(3872) at BESIII Achasov, M N; Albayrak, O; Ambrose, D J ...
Physical review letters,
2014-Mar-07, Volume:
112, Issue:
9
Journal Article
Peer reviewed
Open access
With data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.009 to 4.420 GeV, the process e+e-→ γX(3872) is observed for the first time ...with a statistical significance of 6.3σ. The measured mass of the X(3872) is (3871.9 ± 0.7s tat ± 0.2 syst) MeV/c(2), in agreement with previous measurements. Measurements of the product of the cross section σe+e- → γX(3872) and the branching fraction BX(3872)→π+π-J/ψ at center-of-mass energies 4.009, 4.229, 4.260, and 4.360 GeV are reported. Our measurements are consistent with expectations for the radiative transition process Y(4260) → γX(3872).
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Using 6.32 fb–1 of electron-positron collision data recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, we present the first search for the decay $D^{+}_{s}$ → ...a0(980)0e+νe, a0(980)0 → π0η, which could proceed via a0(980) – f0(980) mixing. No significant signal is observed. An upper limit of 1.2 × 10–4 at the 90% confidence level is set on the product of the branching fractions of $D^{+}_{s}$ → a0(980)0e+νe and a0(980)0 → π0η decays.
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The decays ψ2(3823 ) → γχc0,1,2, π+π− J/ψ, π0π0J/ψ , ηJ/ψ, and π0J/ψ are searched for using the reaction e+e− → π+π− ψ2 (3823) in a 19 fb−1 data sample collected at center-of-mass energies between ...4.1 and 4.7 GeV with the BESIII detector. The process ψ2(3823) → γχc1 is observed in a 9 fb−1 data sample in the center-of-mass energy range 4.3–4.7 GeV, which confirms a previous observation but with a higher significance of 11.8 σ , and evidence for ψ2(3823) → γχc2 is found with a significance of 3.2 σ for the first time. The branching-fraction ratio ... is determined. No significant ψ2 (3823) signals are observed for any of the other decay channels. Upper limits of branching-fraction ratios for ψ2(3823 ) → π+π− J/ψ , π0π0 J/ψ, ηJ/ψ , π0 J/ψ, γ χc0 relative to ψ2 (3823) → γχc1 are reported. The process e+e− → π0π0ψ2 (3823) is also searched for, and we find evidence for the process with a significance of 4.3 σ . The average cross-section ratio σ (e+e− → π0π0ψ2 (3823)) σ (e+e− → π+π− ψ2 (3823)) is also determined. (ProQuest: ... denotes formula omited.).
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In order to better understand the molecular basis of heterosis in maize, the methylation-sensitive amplification polymorphism method was used to estimate patterns of cytosine methylation in seedling ...roots and leaves and 15-d postfertilization embryo and endosperm tissues of hybrids and their parental lines Zheng58 and Chang7-2. In all tissues, total relative methylation levels in the hybrids were lower than corresponding mid-parent values, with a higher number of demethylation events inferred for the hybrids. The trend of reduced methylation and increased demethylation in the hybrids relative to their parents may allow de-repression and possibly the expression of various genes associated with a hybrid phenotypic variation. To further investigate observed methylation pattern changes, we sequenced 50 differentially displayed DNA fragments. The BLAST analysis revealed that 13 fragments shared similarity with known functional proteins in maize or other plant species including proteins related to metabolism, transposons/retrotransposons, development, stress response, and signal transduction. The genes associated with these proteins may thus contribute significantly to maize hybrid vigour.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UL, UM, UPUK, VKSCE, ZAGLJ
We conducted a comparative in vitro study on the proliferative effects of natural human lactoferrin (nhLF) and bovine lactoferrin (bLF) on osteoblasts. We investigated cell proliferation, cell ...survival, cell cycle, and mRNA and protein expression of proliferating cell nuclear antigen. Results indicated that treatment with 100 μg/mL of bLF or nhLF promoted the proliferation and sustenance of osteoblasts, and increased the length of the G2/M and S phases compared with the untreated osteoblasts. Results of real-time quantitative PCR and Western blot showed that mRNA and protein expression of proliferating cell nuclear antigen by osteoblasts treated with bLF or nhLF were greater than those of the untreated control. At the same concentration, bLF demonstrated a greater effect on osteoblast proliferation than did nhLF. This study provides insights of significance in the utlization of bLF in healthy food formulas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8 × ...10(6) positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼ 250 GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena.
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The recent renaissance of black phosphorus (BP) as a two-dimensional (2D) layered material has generated tremendous interest, but its unique structural characters underlying many of its outstanding ...properties still need elucidation. Here we report Raman measurements that reveal an ultralow-frequency collective compression mode (CCM) in BP, which is unprecedented among similar 2D layered materials. This novel CCM indicates an unusually strong interlayer coupling, and this result is quantitatively supported by a phonon frequency analysis and first-principles calculations. Moreover, the CCM and another branch of low-frequency Raman modes shift sensitively with changing number of layers, allowing an accurate determination of the thickness up to tens of atomic layers, which is considerably higher than previously achieved by using high-frequency Raman modes. These findings offer fundamental insights and practical tools for further exploration of BP as a highly promising new 2D semiconductor.
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The observed cross sections for e+e− → μ+μ− at energies from 3.8 to 4.6 GeV are measured using data samples taken with the BESIII detector operated at the BEPCII collider. We measure the muonic ...widths and determine the branching fractions of the charmonium states ψ(4040), ψ(4160), and ψ(4415) decaying to μ+μ−, as well as making a first determination of the phase of the amplitudes. In addition, we observe evidence for a structure in the dimuon cross section near 4.220 GeV/c2, which we denote as S(4220). Analyzing a coherent sum of amplitudes yields eight solutions, one of which gives a mass of MS(4220) = 4216.7 ± 8.9 ± 4.1 MeV/c2, a total width of Γ tot S(4220) = 47.2 ± 22.8 ± 10.5 MeV, and a muonic width of Γ μμS(4220) = 1.53 ± 1.26 ± 0.54 keV , where the first uncertainties are statistical and the second systematic. The eight solutions give the central values of the mass, total width, muonic width to be, respectively, in the range from 4212.8 to 4219.4 MeV/c2, from 36.4 to 49.6 MeV, and from 1.09 to 1.53 keV. The statistical significance of the S(4220) signal is 3.9σ. Correcting the total dimuon cross section for radiative effects yields a statistical significance for this structure of 8.1σ.
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