[en] The interactions between lead (II) acetate and lysozyme in aqueous solution were investigated by fluorescence, UV–vis, surface-enhanced Raman scattering (SERS) and circular dichroism spectroscopies. The activity of lysozyme was inhibited by the addition of lead acetate. The SERS results revealed that the environment of the tryptophan (Trp) residues became more hydrophobic. Synchronous fluorescence spectra confirmed that the conformation of lysozyme had been changed and both tyrosine and tryptophan residues were located in a more hydrophobic environment. The decreased lysozyme activity and fluorescence quenching results showed that lead acetate entered the largest pocket of lyoszyme, and affected the residues in this pocket, including the catalytic residues (Glu 35, Asp 52) and the most dominant fluorophores (Trp 62, Trp 108). The fluorescence measurements suggested different lead acetate species had varying influences on the micro-environment of lysozyme. In addition, the UV–vis spectra indicated that the backbone of lysozyme was changed and circular dichroism showed that the secondary structure of lysozyme displayed a decrease in α-helix and an increase in β-sheet with the increasing amount of lead acetate. -- Highlights: • Spectroscopic results showed interaction details of lead acetate with lysozyme. • Lead acetate binds on the active site of lysozyme. • The toxic model of lysozyme to lead acetate was developed

[en] For the Phase 2 of HLS (Hefei Light Source) Project, many sextupoles and octupoles have been installed in the machine to improve the operation condition. These nonlinear elements will introduce nonlinear effects to the beam dynamics. The authors apply Frequency Map Analysis to the HLS ring. By analyzing the resonance lines on the tune map, the authors find that the calculated lattice of GPLS mode lies on the weak chaotic zone, and the operating mode is better. (authors)

[en] Photo-generated carriers may diffuse into the adjacent cells to form the electrical crosstalk, which is especially noticeable after the pixel cell size has been scaled down. The electrical crosstalk strongly depends on the structure and electrical properties of the photosensitive areas. In this work, time-dependent crosstalk effects considering different isolation structures are investigated. According to the different depths of photo-diode (PD) and isolation structure, the transport of photo-generated carriers is analyzed with different regions in the pixel cell. The evaluation of crosstalk is influenced by exposure time. Crosstalk can be suppressed by reducing the exposure time. However, the sensitivity and dynamic range of the image sensor need to be considered as well. (paper)

[en] To enhance the performance of Hefei Light Source, which was designed and constructed two decades ago, an upgrade project would be carried out in the near future. The detail upgrade scheme was described in this paper. Firstly, the magnet lattice of storage ring should be reconstructed with 4 DBA cells, whose advantages are lower beam emittance and more straight section available for insertion devices. Secondly, the beam diagnostics, main power supply, transverse and longitudinal multi-bunch feedback, beam control and manipulation system would be upgrade to improve the beam orbit stability. Finally, the injection system of storage ring and injector, which is composed of electron linac and beam transfer line, would be updated in order to assure smooth beam accumulation process under new low emittance lattice. With above improvement, it is hopeful to increase the brilliance of Hefei Light Source by two orders approximately. After three-year upgrade project, the performance of HLS would meet the demands of advanced SR users.

[en] Pulse bump orbit technique can realize adjustable interval of Hefei light source HLS light pulse. In order to obtain high-current short pulse with high repeat frequency for the fast kicker, the experimental study based on the MOSFET solid modulator technique was carried out. The designed prototype has the structure of a 10-group MOSFET switch parallel and a 6 level inductive-adder, including fast trigger signal production, power drive circuit's design, inductive-adder type configuration. The de- vice obtains a pulse output of 100 ns width, 20 kHz repeat rate, 60 A summit current and 2 kV peak voltage. (authors)

[en] Based on the effective spin-ladder model, we study the properties of quantum dissonance (Q) between two edge spins in chiral graphene nanoribbons (CGNRs) thermalized with a reservoir at temperature T, and discuss the influences of relative location between two edge spins, ribbon width, temperature, and on-site Coulomb repulsion (U) on Q. The results show that Q is widely present in Wannier edge states. For intra-edge coupled spin pairs, quantum entanglement (E) is zero, but there still exists considerable value of Q. Interestingly, Q always keeps a constant for entangled edge spin pairs. Considering the thermal effect, it shows that Q always decays with the increasing temperature T, and the decay rate is very sensitive to the intensity of U. Compared Q with E and total quantum correlation (quantum discord, denoted by D), we conjecture that the quantum correlations for a bipartite Wannier edge state in CGNRs satisfy the relation Q  ⩽  D–E. (paper)

[en] β-eucryptite powders are prepared by the sol–gel method through using tetraethoxysilane lithium nitrate and aluminum isopropoxide as starting materials. β-eucryptite ceramics are prepared by spark plasma sintering. The effects of sintering temperature on the negative thermal expansion properties of the β-eucryptite are investigated by x-ray diffraction (XRD), scanning electron microscopy, and thermal expansion test. The XRD results exhibit no change in the crystal structure of the sample prepared by different sintering processes. The negative thermal expansion properties increase with the increase of the sintering temperature. The coefficient of thermal expansion of β-eucryptite ceramics sintered at 1100 °C is calculated to be −4.93 × 10⁻⁶ °C⁻¹. Crystallization behaviors of the ceramics may play an important role in the increase of negative thermal expansion of β-eucryptite. High sintering temperature could improve the crystallization behaviors of the ceramics and reduce the residue glass phase, which can improve the negative thermal expansion properties of β-eucryptite ceramics. (paper)

[en] Structural properties of the pure water and halogen solutions at high temperatures and pressures are studied by using the molecular dynamics simulations and quantum molecular simulations. The related characters are calculated as functions of temperature and pressure. The results show that the hydrogen bonded networks become looser as temperature increases, with the collapse of the traditional tetrahedral structure. It is similar to the concentration-dependent collapse in the NaCl solutions. However, adding other halogen elements has no further effects on the already weakly bonded water molecules. At the phase changing points, the process of hydration is evident for the bigger ions, so that the bigger the ion is, the smaller a cluster is formed. (paper)

[en] The modulational instability of two-component Bose–Einstein condensates (BECs) under an external parabolic potential is discussed. Based on the trapped two-component Gross–Pitaevskill equations, a time-dependent dispersion relation is obtained analytically by means of the modified lens-type transformation and linear stability analysis. It is shown that a modulational unstable time scale exists for trapped two-component BECs. The modulational properties—which are determined by the wave number, external trapping parameter, intra- and inter-species atomic interactions—are modified significantly. The analytical results are confirmed by direct numerical simulation. Our results provide a criterion for judging the occurrence of instability of the trapped two-component BECs in experiment. (paper)

[en] The ship turning motion can reflect the turning characteristics of the ship and is closely related to the navigation safety of the ship. In the turning performance test, the trajectory drawn by the center of gravity of the ship is called the turning circle. The turning circle is an important indicator to characterize the turning performance of a ship. At present, the results of ship turning obtained by numerical calculations are still very different from the test ones. In this paper, the free turning motion of a container ship is simulated by a commercial software which is called STARCCM+. In order to reduce the amount of calculation, a body-force propeller model is adopted to replace the real propeller. Through the global solution of the fully viscous flow field, the characteristic parameters and the motion track of the ship turning motion can be gotten. The ship’s motion trajectory and the parameters of the turning motion obtained by numerical prediction are in good agreement with the test values, which fully proves the applicability and reliability of the proposed method in numerical prediction. (paper)