[en] Motivated by the recent ATLAS results in terms of the branching ratios Br(t → qγ), we consider the effects of the anomalous tqγ couplings on the radiative B meson decays $\stackrel{¯<!--\; ??\; -->}{B}\to <!--\; ???\; -->X_D\mathrm{\gamma <!--\; ??\; -->}$ and B → Vγ with V being light vector mesons ρ, ω, ϕ and K ^*. Comparing with the corresponding experimental measured data, we obtain the constraints on anomalous tqγ couplings. (paper)

[en] The effects of different additives on the compost of Camellia oleifera shell were characterized and a maturity evaluation system for the obtained compost was established. Four treatments were designed as C. oleifera shell with C. oleifera seed meal (A1), with C. oleifera seed cake (A2), with sheep manure (A3), and with spent mushroom substrate (A4). A3 had the longest thermophilic phase (over 50 °C) and shortest cooling phase. Compared with A1, the thermophilic phase of A2 was postponed 11 days due to the high lipid content, but terminated almost at the same time. The temperature of A4 increased slowly and took longer time to reach ambient. C/N, pH, E4/E6, and NH₄⁺-N decreased along with composting process, while TN, GI, and NO₃⁻-N were opposite. Based on the Pearson correlation analysis with the Solvita maturity index as a reference, the result indicated that TN, C/N, GI, NH₄⁺-N, and pH can be used for the maturity evaluation.

[en] Objective: To identify the steps with potentially higher risk through the analysis of human factors in clinical PET application so as to provide the efficient measures to reduce the risk of potential exposures. Methods: The basic data were obtained through field investigation, questionnaire,failure mode, risk identification, FMECA and expert's evaluation, with statistical analysis made. Comparison was made of the relative risk values of automatic encapsulation equipment and manual encapsulation ones. Results: The 10 steps with potentially higher risks were identified through analyzing human factors of clinical PET application, of which 8 occurred in the phase of chemical synthesis.The measures to control risk were addressed for the steps with higher risk. The results show that the relative risk value of the clinical process with automatic encapsulation equipment was 2.28 ± 0.99 and the one with manual encapsulation equipment was 3.20 ± 2.01 (t=2.56, P<0.05), with the latter being 76% of the former. Conclusions: Failure mode and FMECA are effective in risk evaluation of clinical PET application, which can provide important basis for risk control. (authors)

[en] A method to correct the longitudinal chromatic aberration (LCA) between the imaging beam (IB) and beacon beam of ocular adaptive optics (AO) imaging system is presented, by inserting trial spherical lens, i.e. chromatic aberration corrector (CAC), on the imaging light path. The LCA of the optical system, and the quantitative relation between the CAC diopter and the IB focus shift, are determined experimentally. Then the CAC diopter required for human eye imaging can be determined by using above results combined the existing ocular LCA data. The feasibility of this method was proved by imaging results of different samples with a model eye. Finally, the method was demonstrated to significantly improve the imaging effect in in vivo retinal AO optical coherence tomography imaging of volunteers. It does not require additional burdens, is easy-to-use and suitable for various ocular AO imaging systems. (paper)

[en] In this paper, we report unusual thermal hysteresis behaviour in half-doped manganites Nd_0.5Sr_0.5-xCa_xMnO₃ (0.0 ≤ x ≤ 0.50). For 0.05 ≤ x < 0.25 samples, the magnetization curves show a counterclockwise hysteresis loop. For 0.25 < x ≤ 0.40 samples, however, they exhibit a clockwise loop. The inverse hysteretic behaviour stems from the competition between two kinds of strain, namely, the compressive strain and the tensile strain. The former produces a counterclockwise thermal hysteresis while the latter leads to a clockwise one. In the meantime, a magnetic instability is observed and the strain relaxation should be the main reason for it

[en] The electrical and magnetic properties of Ln_0.4Ca_0.6MnO₃ compositions (Ln = La, Pr, Nd, Sm) have been investigated. The effect of < r_A> on the charge-ordering behavior of the manganites is considered to be profound. The charge-ordering temperature T_CO increases with decreasing < r_A>, the antiferromagnetic charge-ordering state transforms from long-range into local short-range ordering and the magnetic behaviors for Ln = La, Pr, Nd, Sm are all different. Through the M-T, M-H, and electron spin resonance measurements, it is found that the magnetization in M-T curves comes from the paramagnetic contribution of disordered Mn ions at the B-site and magnetic ions at the A-site. The rise of T_CO is attributed to the fact that e_g electrons are localized by decreasing < r_A>, and the different behavior of M-T curves below T_CO originates from the number of remaining spin disordered Mn ions after the formation of the charge-ordering phase in the manganites

[en] The compound diffractive telescope is a novel space optical system which combines the structure of compound eyes with diffractive optics and so it has a lighter weight, a wider field of view (FOV), a lower cost as well as looser fabrication tolerance. In this paper, the design of a compound diffractive telescope composed of one primary lens and twenty-one eyepieces is introduced. Then the influence of diffraction orders on the performance of the system is analysed. A modified phase function model of diffractive optics is proposed to analyse the modulation transfer function (MTF) curves for 0deg FOV, which provides a more accurate prediction of the performance of the system. In addition, an optimized mechanism is also proposed to suppress stray light. The star image and resolution tests show that the system can achieve diffraction limit imaging within deg 2deg of FOV and deg 4 mm of eccentricity. Finally, a series of pictures of an object are taken from different channels, and the splicing of pictures from adjacent FOVs is demonstrated. In summary, the designed system has been proved to have great potential applications. (general)

[en] To monitor the beam profile at the end of the linac non-destructively, a wire scanner as a new diagnostic instrument was designed, manufactured and installed in 2007. Since then, several measurements have been carried out using this device. This paper describes the whole system of the wire scanner and the testing results. (authors)

[en] Highlights: • A novel utilization of the vanadium-bearing titanomagnetite concentrates is presented. • Increasing sintering temperature can facilitate formation of laminated pearlites. • Increasing sintering time can also facilitate formation of laminated pearlites. • The economical sintering time should not be more than 3 h. - Abstract: In order to optimize an innovative two-stage process for preparing an iron-based friction material directly from vanadium-bearing titanomagnetite concentrates, this paper focuses on the effects of sintering process on the microstructures and properties of an iron-based friction material. On one hand, the samples were sintered at 900 °C, 950 °C, and 1000 °C for 3 h respectively; On the other hand, the samples were sintered at 1000 °C for 1 h, 2 h, 3 h, and 4 h respectively. As a result, after the samples were sintered at above 950 °C for more than 3 h, a lot of laminated microstructures appear in these samples owing to the formation of a large number of pearlites. Besides, the density, the hardness, and the friction coefficient of this material are positively correlated to the sintering temperature or the sintering time, and the wear rate of this material is negatively related to the sintering temperature or the sintering time. This study can contribute to the attainment of much clearer insight into the effects of sintering process and lay the foundation of practical application of this innovative two-stage process.

[en] Parametric amplification is widely used in nanoelectro-mechanical systems to enhance the transduced mechanical signals. Although parametric amplification has been studied in different mechanical resonator systems, the nonlinear dynamics involved receives less attention. Taking advantage of the excellent electrical and mechanical properties of graphene, we demonstrate electrical tunable parametric amplification using a doubly clamped graphene nanomechanical resonator. By applying external microwave pumping with twice the resonant frequency, we investigate parametric amplification in the nonlinear regime. We experimentally show that the extracted coefficient of the nonlinear Duffing force α and the nonlinear damping coefficient η vary as a function of external pumping power, indicating the influence of higher-order nonlinearity beyond the Duffing (∼x ³) and van der Pol (∼$x^2\frac{dx}{dt}$) types in our device. Even when the higher-order nonlinearity is involved, parametric amplification still can be achieved in the nonlinear regime. The parametric gain increases and shows a tendency of saturation with increasing external pumping power. Further, the parametric gain can be electrically tuned by the gate voltage with a maximum gain of 10.2 dB achieved at the gate voltage of 19 V. Our results will benefit studies on nonlinear dynamics, especially nonlinear damping in graphene nanomechanical resonators that has been debated in the community over past decade. (paper)