[en] In an effective Lagrangian model we find that the N * (1535) resonance contribution might be important to the interpretation of the present data of the pp → ppη' and pn → dφ reactions. The strong coupling strength of N *(1535) to η' and φ are indicated, and the possible implication to the intrinsic component of N * (1535) is explored. These results may provide hints to the real origin of the OZI rule violation. It is stressed that further measurements could be performed at the Cooling Storage Ring (CSR) at Lanzhou of China. (author)

[en] A coupled-channel model based on effective Lagrangians is applied to the combined analysis of the (π,γ) N → KΣ reactions up to the center of mass energy 2 GeV. The couplings constants and resonance parameters of the KΣ state are extracted in the calculation. The main resonance contributions to the process come from the S₁₁(1650), D₁₃(1520), D₁₅(1675), P₁₃(1900), P₃₁(1750), D₃₃(1700) and D₃₅(1930) states. The coherent sum of resonances and background contributions is essential to describe the recent photoproduction data obtained by the CLAS, CBELSA, LEPS, and GRAAL groups.

[en] A solar-powered transcritical CO₂ (carbon dioxide) power cycle for reverse osmosis desalination based on the recovery of cryogenic energy of LNG (liquefied natural gas) is proposed. The system consists of a solar collector subsystem, a transcritical CO₂ power cycle subsystem, a LNG subsystem and a RO (reverse osmosis) desalination subsystem. A thermal storage unit is introduced into the system to guarantee continuous and stable operation of the system. A mathematical model is developed to simulate the system based on several assumptions. The effects of several key thermodynamic parameters on the system performance are examined based on the performance criteria, including daily exergy efficiency, daily mechanical work output and daily fresh work output. Parametric optimization is conducted by genetic algorithm to maximize the daily fresh water output. The results show that the CO₂ turbine inlet pressure has an optimal value to reach the daily maximum exergy efficiency under the given conditions. The daily exergy efficiency could decrease with an increase in condenser temperature, and increase with an increase in mass flow rate of oil and NG turbine inlet pressure. Through parametric optimization, the system can reach the daily exergy efficiency of 4.90% and provide 2537.33 m³ fresh water per day under the given conditions. - Highlights: • A solar-powered transcritical CO₂ cycle with LNG as heat sink for RO is proposed. • Parametric sensitive analysis is done to examine their effects on the performance. • Parametric optimization is conducted to obtain optimum system performance

[en] Topomer CoMFA is used to build a three-dimensional quantitative structure activity relationship (3D-QSAR) model for 26 coumarin derivatives in this paper. The coefficients of cross validation, non-cross validation and external validation are 0.666, 0.973 and 0.960, respectively. The result showed that this model has a good stability and a predictive ability. Using this information for molecular docking, it is theoretically verified that the model constructed has high credibility, and the QSAR results could offer a theoretical reference for the pharmaceutical synthesis. (authors)

[en] We report on a theoretical study of the π⁻ p → a₁ ⁻(1260)p and π⁻p → π⁻ ρ⁰p reactions near threshold within an effective Lagrangian approach. The production process is described by t-channel ρ⁰ meson exchange. For the π⁻p → π⁻ρ⁰p reaction, the final π⁻p⁰ results from the decay of the a₁(1260) resonance, which is assumed as a dynamically generated state from the K*K̄ and ρπ coupled channel interactions. We calculate the total cross section of the π⁻p → a₁ ⁻(1260)p reaction. It is shown that, with the coupling constant of the a₁(1260) to ρπ channel obtained from the chiral unitary theory and a cut off parameter Λ_ρ ∼ 1.5 GeV in the form factors, the experimental measurement can be reproduced. Furthermore, the total and differential cross sections of π⁻p → a₁ ⁻(1260)p → π⁻ρ⁰p reaction are evaluated, and it is expected that our model calculations can be tested by future experiments. These reactions are important for the study of the a₁(1260) resonance and would provide further constraints on the properties of the a₁(1260) state. (paper)

[en] By solving the three-dimensional time-dependent Schrödinger equation, we present a theoretical investigation of helium-based high-order harmonic generation (HHG) in both symmetric and asymmetric spatially nonhomogeneous laser fields. It is determined that the harmonic cutoff is extended in both symmetric and asymmetric nonhomogeneous laser fields, and the spatial symmetry of the nonhomogeneous field greatly influences the movement of electronic wave packets, which subsequently affect harmonic emission. In particular, the spatially asymmetric distribution of the laser field will induce asymmetric recombination of electronic wave packets between the two sides of a helium atom, which could reduce the interference in HHG emission for every optical cycle. In combination with the two-color technique, multi-cycle laser pulses with asymmetric spatially nonhomogeneous characteristics are capable of generating a coherent extreme ultraviolet supercontinuum, which can be used to produce isolated few-attosecond pulses. (paper)

[en] For their distinguished global warming potential (GWP100) and long atmosphere lifespan, CF_4, SF_6 and SF_5CF_3 were significant in the field of greenhouse gas research. The details of discharging character and the optimal parameter were discussed by using a Dielectric Barrier Discharge (DBD) reactor to decompose these potent greenhouse gases in this work. The results showed that SF_6 could be decomposed by 92% under the conditions of 5 min resident time and 3000 V applied voltage with the partial pressure of 2.0 kPa, 28.2 kPa, and 1.8 kPa for SF_6, air and water vapor, respectively. 0.4 kPa CF_4 could be decomposed by 98.2% for 4 min resident time with 30 kPa Ar added. The decomposition of SF_5CF_3 was much more effective than that of SF_6 and CF_4 and moreover, 1.3 kPa SF_5CF_3, discharged with 30 kPa O_2, Ar and air, could not be detected when the resident time was 80 s, 40 s, and 120 s, respectively. All the results indicated that DBD was a feasible technique for the abatement of potent greenhouse gases. (paper)

[en] We report the measurements of the anisotropic magnetization and magnetoresistance (MR) on single crystals of EuFe₂As₂, a parent compound of ferro-arsenide high-temperature superconductor. Apart from the antiferromagnetic (AFM) spin density wave (SDW) transition at 186 K associated with Fe moments, the compound undergoes another magnetic phase transition at 19 K due to AFM ordering of Eu²⁺ spins (J=S=7/2). The latter AFM state exhibits metamagnetic (MM) transition under magnetic fields. Upon applying magnetic field with H parallel c at 2 K, the magnetization increases linearly to 7.0 μ_B f.u.^-1 at μ₀H=1.7 T and then remains at this value for saturated Eu²⁺ moments under higher fields. In the case of H parallel ab, the magnetization increases step-like to 6.6 μ_B f.u.^-1 with small magnetic hysteresis. An MM phase was identified with the saturated moments of 4.4 μ_B f.u.^-1. The MM transition accompanies negative in-plane MR, reflecting the influence of Eu²⁺ moments ordering on the electrical conduction of FeAs layers. These results were explained in terms of spin-reorientation and spin-reversal based on an A-type AFM structure for Eu²⁺ spins. The magnetic phase diagram has been established.

[en] Lepton scattering is an established ideal tool for studying inner structure of microscopic particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High intensity heavy-ion accelerator facility (HIAF) which is currently under construction, together with an additional electron ring. The proposed collider will provide highly polarized electrons (with the polarization ∼80%), protons and Helium-3 (both with the polarization ∼70%), as well as unpolarized ion beams from carbon to uranium with viable center of mass energy from 15 GeV to 20 GeV and the luminosity of (2 ∼ 4) × 10³³cm^-2·s^-1. The main foci of the EicC will be the precision measurements of proton structure in the sea quark region, including 3 D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment, in particular, the short range correlation of nucleons and the cold nuclear matter effects; the exotic hadronic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with the cutting-edge technology. During preparation of the document, we have received valuable inputs and help from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and hadron physics as well as accelerator and detector technology in China. (authors)

[en] Objective: Using Cerenkov radiation energy transfer (CRET) effect of rare earth nanoparticles (RENPs) to enhance and convert Cerenkov luminescence into Cerenkov luminescence excited fluorescence, and to compare the accuracy of Cerenkov luminescence tomography (CLT) and Cerenkov luminescence excited fluorescence tomography (CLFT). Methods: ⁶⁸Ga (0.74 MBq) was used to respectively excite Y_2O3 : Eu³⁺, Er₂O₃ and Eu2_O3 (10 mg/ml). Various radioactivities of ⁶⁸Ga (3.70, 1.85, 0.92, 0.46, 0.23 MBq) were used to respectively excite Y₂O₃ : Eu³⁺ with a fixed concentration (10 mg/ml). A fixed radioactivity of ⁶⁸Ga (3.70 MBq) was used to excite Y₂O₃ : Eu³⁺ with different concentrations (10.0, 5.0, 2.5, 1.2, 0.6 mg/ml) in order to find the relationships between the optical intensity and the radioactivity of ⁶⁸Ga or the concentration of Y₂O₃ : Eu³⁺. Polyethylene tubes containing ⁶⁸Ga (0.74 MBq) and ⁶⁸Ga (0.74 MBq)+Y₂O₃ : Eu³⁺ (1 mg) were respectively implanted into two nude mice, then PET/CT and optical imaging were acquired. Three-dimensional reconstruction was proceeded. One-way analysis of variance, two-sample t test, linear correlation analysis were used for data analysis. Results: Y₂O₃ : Eu³⁺ could significantly and stably enhance the Cerenkov optical signal (F = 53.35, q = 17.03, P < 0.001). The enhanced optical signal intensity had linear relationships with the radioactivity of ⁶⁸Ga or the concentration of Y₂O₃ : Eu³⁺ (r values: 0.99 and 0.93). Three-dimensional reconstruction result showed that CLFT had significantly higher similarity than CLT (0.43 ± 0.14 vs 0.16 ± 0.06, t = 5.090, P < 0.05). Conclusion: CLFT could reflect the distribution of radiopharmaceuticals more precisely than CLT, and therefore might have potential in biologic optical imaging. (authors)