Results 1 - 10 of 215
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[en] The study focuses on the contact nonlinear computation method for multi-subassemblies interaction, and tries to verify the extendibility of the method proposed by Likhachev and the viability of resolving CEFR subassembly contact problem. Based on the computation method developed by Likhachev, the consistent deformation conditions and the system potential energy equations for multi-subassemblies are established at three contact levels instead of two levels. The minimum potential energy principle is utilized to acquire the contact forces. For simplicity, orthogonal transform and Lagrangian-double-problem transformation are used. Finally, the nonlinear contact analysis turns into the optimization of a quadratic function with conditional inequality constraints. Conclusions are as follows: Likhachev method can be extended for three contact levels from two, and is generally practicable; the final derived expression is a common problem in optimization theory, which could be easily solved numerically. (authors)
[en] We present a unified parametrization of quark and lepton mixing matrices. By using some simple relations between the mixing angles of quarks and leptons, i.e., the quark-lepton complementarity, we parametrize the lepton mixing matrix with the Wolfenstein parameters λ and A of the quark mixing matrix. It is shown that the Wolfenstein parameter λ can measure both the deviation of the quark mixing matrix from the unit matrix, and the deviation of the lepton mixing matrix from the exactly bimaximal mixing pattern
[en] Metastable phase formation and magnetic properties of the Fe50(HfxTa1−x)50 (x = 0, 0.2, …, and 1) thin films induced by ion beam mixing are studied. The results show that unique amorphous phases could be formed in all the six multilayered films. Interestingly, preferred orientations and formation of BCC-Hf phase were observed in the Fe50Hf50 multilayered films at as-deposited state and after irradiated to doses less than 6 × 1014 Xe+/cm2. In addition, good soft magnetic properties were obtained in the formed amorphous phases. The Fe50Hf40Ta10 amorphous phase owns the maximum magnetization of 45 emu/g (i.e., 1.21 μB per Fe atom) at 5 K, with a saturate magnetization of 7.5 emu/g and a small coercivity Hc = 7 Oe at room temperature. The possible mechanisms responsible for the observations are discussed in terms of atomic collision theory and crystallography.
[en] A CT technique applied to ICF experiments has been studied and it has been used to analyse the measured X-ray in laser-plasma experiments at 'Xingguang II' device. The three-dimensional distribution of the X-rays in targets is reconstructed and useful results are obtained. This shows that the qCT technique can be applied to ICF experiments
[en] The valence-band structure of graphite was investigated by UPS and XPS, and the result was compared with the theoretical result of Painter et al. Due to the interaction of C-atom with Ni-atom, Ni3C was observed after vapor deposition of Ni on graphite surface. The C 2px,y orbital is raised up to 5 eV below the Fermi level, while the C 2pz orbital is approaching the Fermi level closely after formation of Ni3C
[en] Highlights: • Porous spinel (MgAl_2O_4) ceramics were prepared from magnesite and Al(OH)_3 with TiO_2 addition. • The amount of TiO_2 added (ATA) affected the formation of liquid phase at sintering temperature. • The optimized product is a specimen with 1.5 wt% ATA which has high apparent porosity and strength. - Abstract: Porous spinel (MgAl_2O_4) ceramics were prepared from magnesite and Al(OH)_3 with TiO_2 addition through an in-situ decomposition pore-forming technique. The porous ceramics were characterized through X-ray diffractometer (XRD), scanning electron microscopy (SEM), and mercury porosimetry measurements, etc. The effect of TiO_2 addition on the phase compositions, pore characterizations and strengths was investigated. The results showed that the amount of TiO_2 added (ATA) affected the formation of liquid phase at sintering temperature, changed the porosity, the pore size distribution and the neck bonds, thus affecting the strength of the porous ceramics. With an increase in ATA, the liquid content at sintering temperature increased, the neck bonds developed better, the porosity decreased, and the average pore size and strength increased. The optimized product is a specimen with 1.5 wt% ATA which has a high apparent porosity (53.0%), a small average pore size (5.95 μm), a high compressive strength (21.2 MPa), a high flexural strength (8.5 MPa) and a relatively homogeneous pore size distribution
[en] Because of the noncommutation of spatial averaging and temporal evolution, inhomogeneities and anisotropies (cosmic structures) influence the evolution of the averaged Universe via the cosmological backreaction mechanism. We study the backreaction effect as a function of averaging scale in a perturbative approach up to higher orders. We calculate the hierarchy of the critical scales, at which 10% effects show up from averaging at different orders. The dominant contribution comes from the averaged spatial curvature, observable up to scales of ∼200 Mpc. The cosmic variance of the local Hubble rate is 10% (5%) for spherical regions of radius 40 (60) Mpc. We compare our result to the one from Newtonian cosmology and Hubble Space Telescope Key Project data.
[en] Two empirical formulas for the lepton and quark masses (i.e. Kartavtsev's extended Koide formulas), K_l = (sum _lm_l)/(sum _l√(m_l))"2 = 2/3 and K_q = (sum _qm_q)/(sum _q√(m_q))"2 = 2/3, are explored in this paper. For the lepton sector, we show that K_l = 2/3, only if the uncertainty of the tauon mass is relaxed to about 2σ confidence level, and the neutrino masses can consequently be extracted with the current experimental data. For the quark sector, the extended Koide formula should only be applied to the running quark masses, and K_q is found to be rather insensitive to the renormalization effects in a large range of energy scales from GeV to 10"1"2 GeV. We find that K_q is always slightly larger than 2/3, but the discrepancy is merely about 5%. (orig.)
[en] This paper discuss a 800 Msps data acquisition system using MAX105 device. The system achieves a sampling rate of 800 Msps, and converts the high speed LVDS signals to low speed LVTTL signals using FPGA. And the FPGA implements the amplitude discrimination and obtains time information. Then FPGA sends the data to the TELL1 readout board. The TELL1 board sends the data to the Gigabit ethernet with the Gigabit Ethernet link. (authors)
[en] Cosmological backreaction has been suggested as an explanation of dark energy and is heavily disputed since. We combine cosmological perturbation theory with Buchert's nonperturbative framework, calculate the relevant averaged observables up to second order in the comoving synchronous gauge, and discuss their gauge dependence. With the help of an integrability condition, the leading second order contributions follow from the first order calculation. We focus on the onset of cosmological backreaction, as a perturbative treatment is necessarily restricted to the era when the effect is still small. We demonstrate that the leading contributions to all averaged physical observables are completely specified on the boundary of the averaged domain. For any finite domain, these surface terms are nonzero in general and thus backreaction is for real. We map the backreaction effect on an effectively homogeneous and isotropic fluid. The generic effective equation of state is not only time dependent, but also depends on scale