[en] A self-consistent thermodynamic description of the Al–Si–P ternary system was developed. Based on that, the first consistent and experimentally supported Al–Si–P phase diagram was calculated. The P-threshold – excluding the formation of potent AlP nucleants before eutectic (Si) – was elaborated using both normal Scheil and equilibrium solidification simulation. Its quantitative dependence on the Si content of the alloy was determined and a precipitation sequence map, covering all Si and P compositions relevant for Al–Si cast alloys, was predicted from these thermodynamic calculations. The predicted map was validated by independent experimental studies on hypoeutectic Al–Si alloys and it is in perfect agreement with microstructure observation and undercooling measurements. Moreover, a constrained Scheil solidification simulation technique was applied to predict the undercooling under clean heterogeneous nucleation conditions and these data are in perfect agreement with dedicated experimental observations from the entrained droplet technique. Even for extremely low P-content and large undercooling the direct nucleation of (Si) on primary (Al) does not occur but is triggered by the formation of AlP under clean conditions. The P-threshold is not trivial since it varies from zero to 7.4 ppm P for hypoeutectic alloys, which is just in or below the commercial purity range of regular Al–Si cast alloys

[en] Purpose: To analyze the CT appearances and clinical aspects of the degeneration at atlanto-odontoid(A-O) joint. Methods: Thin section axial CT scans, of AO joints were studied in 317 consecutive patients who underwent brain or cervical spine CT examinations. The images were viewed using double-blind method. Observation included: osteophytosis, changes of joint space and transverse ligament, and the clinical symptoms as well. Results: CT findings of AO joint degeneration included: formation of osteophyte, narrowing of joint space, transverse ligament calcification, and joint vacuum phenomenon. Among individuals above 40 years of age, the incidence of degeneration at AO joint went up gradually (P<0.01). Conclusion: Degeneration of AO joint was not uncommon among aged people, CT could better demonstrate the pathological changes

[en] DNA-protein complexes (DPCs) are composed of both normal and abnormal associations of DNA primarily with proteins of the nuclear matrix. Although the number of fragments of DNA linked to protein increases after irradiation, the normal and radiation-induced DPCs share two characteristics, the identity of the proteins involved and the enrichment of the DNA for actively transcribing sequences. There are several implications of these central features of DPCs. First, DPC formation in irradiated cells appears to occur in a non-random fashion preferentially to regions of DNA containing active sequences at or near the nuclear matrix. DNA single-strand breaks were likewise observed to be produced preferentially in active regions of the genome. We speculate that a special environment provided by the nuclear matrix makes it an ideal region for DPC formation. Perhaps it allows accessibility of hydroxyl radicals to the DNA, because of the more open conformation of active DNA or a more highly hydrated milieu as compared to regions of the nucleus containing tightly condensed chromatin. 34 refs., 3 figs

[en] In this paper, we investigate the decay of the Higgs boson to J/φ(γ) plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width for process H → J/φ(γ) direct production at the LO is significantly reduced by the NLO QCD corrections. For the indirect process, we calculate the H → γ*γ with virtual y substantially decaying to J/φ(γ), including all the SM Feynman diagrams. The decay width of indirect production is much larger than the direct decay width. Since it is very clean in experiment, the H → J/φ(γ)+γ decay could be observable at a 14 TeV LHC and it also offers a new way to probe the Yukawa coupling and New Physics at the LHC. (authors)

[en] The Higgs boson production in association with a pair of W bosons at the Large Hadron Collider (LHC) can be used to probe the coupling between the Higgs boson and vector gauge bosons and discover the signature of new physics. We describe the impact of the complete QCD next-to-leading order (NLO) radiative corrections and the gluon-gluon fusion subprocesses to the cross section of this process at the LHC and investigate the dependence of the leading order (LO) and QCD corrected cross sections on the factorization/renormalization energy scale and Higgs boson mass. We present the LO and QCD corrected distributions of the invariant mass of a W boson pair and the transverse momenta of the final W and Higgs boson. We find that the QCD NLO corrections and the contribution from a gluon-gluon fusion subprocess significantly modify the LO distributions, and the scale dependence of the QCD corrected cross section is badly underestimated by the LO results. Our numerical results show that the K-factor of the QCD correction varies from 1.48 to 1.64 when m_H goes up from 100 GeV to 160 GeV. We find also the QCD correction from the gg→H⁰W⁺W^- subprocess at the LHC is significant and should be considered in precise experiment.

[en] The high-temperature dielectric properties of SiO₂/Si₃N₄ nanocomposites are investigated theoretically and experimentally. Its permittivities and loss tangents at the temperature ranging from room temperature to 1300°C at 9.0 GHz are measured by the resonant cavity method. The SiO₂/Si₃N₄ nanocomposites show complex dielectric behaviour at elevated temperature, and a multi-scale model is proposed to describe the dependence of the dielectric properties in the SiO₂/Si₃N₄ on its compositional variations. Such a theory is needed so that the available property measurements could be extrapolated to other operating frequencies and temperatures. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

[en] Even small amounts of Phosphorus and Strontium strongly affect the microstructure of hypoeutectic Al–Si alloys. P is an unavoidable trace element in commercial Al-alloys which causes formation of AlP particles as potent nucleation sites for eutectic (Si). Sr, in contrast, is purposely added to modify the morphology of eutectic (Si) towards fine coral-like fibers. It is hypothesized that Sr does not only alter the growth kinetics of (Si), but additionally prevents detrimental (Si) nucleation due to neutralization of AlP particles by Al_2Si_2Sr formation. This presumes that both AlP and Al_2Si_2Sr precipitate prior to (Si). Using a newly assessed thermodynamic database for the Al–Si–Sr–P system, critical P and Sr thresholds for pre-silicon formation of AlP and Al_2Si_2Sr were evaluated and mapped under equilibrium and Scheil conditions. The competitive precipitation of AlP, Al_2Si_2Sr and (Si) and its impact on the evolution of the eutectic morphology was further studied by 3D phase-field simulations. Effective anisotropy functions for the (Si) interface mobility considered Sr-induced internal twinning. Depending on whether subcritical or supercritical P and Sr contents were selected, either a fine lamellar structure, a coarse flaky structure, or the targeted fine fibrous eutectic structure was reproduced

[en] We calculate the next-to-leading order QCD corrections to the J/ψ+W production at the LHC, and provide the theoretical distribution of the J/ψ transverse momentum. Our results show that the differential cross section (dσ/dp_T^J/ψ) at the leading order is significantly enhanced by the next-to-leading order QCD corrections. We believe that the comparison between the theoretical predictions for the J/ψ+W production and the experimental data at the LHC can provide a verification for the color-octet mechanism of nonrelativistic QCD in the description of the processes involving heavy quarkonium.

[en] Nearly all displacive transitions have been considered to be continuous or second order, and the rigid unit mode (RUM) provides a natural candidate for the soft mode. However, in-situ X-ray diffraction and Raman measurements show clearly the first-order evidences for the scheelite-to-fergusonite displacive transition in BaWO₄: a 1.6% volume collapse, coexistence of phases, and hysteresis on release of pressure. Such first-order signatures are found to be the same as the soft modes in BaWO₄, which indicates the scheelite-to-fergusonite displacive phase transition hides a deeper physical mechanism. By the refinement of atomic displacement parameters, we further show that the first-order character of this phase transition stems from a coupling of large compression of soft BaO₈ polyhedrons to the small displacive distortion of rigid WO₄ tetrahedrons. Such a coupling will lead to a deeper physical insight in the phase transition of the common scheelite-structured compounds. (condensed matter: structural, mechanical, and thermal properties)

[en] High energy colliders provide a new unique way to determine the microscopic properties of dark matter (DM). Weakly interacting massive particles (WIMPs) are widely considered as one of the best DM candidates. It is usually assumed that the WIMP couples to the SM sector through its interactions with quarks and leptons. In this paper, we investigate the DM pair production associated with a Z boson in an effective field theory framework at the international linear collider, which can be used to study the interactions between the DM and leptons. For illustrative purposes, we present the integrated and differential cross sections for the e⁺e^- → χ anti χ Z process, where the Z boson is radiated from the initial state electron or positron. Meanwhile, we analyze the neutrino pair production in association with a Z boson as the SM background. (orig.)