[en] The cross section of atomic electron Compton scattering $\mathrm{\gamma <!--\; ??\; -->}+e\to <!--\; ???\; -->{\mathrm{\gamma <!--\; ??\; -->}}^{\mathrm{\prime <!--\; ???\; -->}}+e^{\mathrm{\prime <!--\; ???\; -->}}$ was measured in the 4.40 - 5.475 GeV photon beam energy region by the PrimEx collaboration at Jefferson Lab with an accuracy of 2% and less. The results are consistent with theoretical predictions that include next-to-leading order radiative corrections. The measurements provide the first high precision test of this elementary QED process at beam energies greater than 0.1 GeV.

[en] The quench behavior of Bi₂Sr₂CaCu₂O_x (Bi2212) wire is investigated through numerical simulations. This work is part of the U.S. Very High Field Superconducting Magnet Collaboration (VHFSMC). Numerical simulations are carried out using a one-dimensional computational model of thermal transport in Bi2212 composite wires. A quench is simulated by introducing heat in a section of the wire, and the voltage and temperature are monitored as function of time and position. The quench energy, normal zone propagation velocity, and spatial distribution of temperature are calculated for varying transport current and applied magnetic field. The relevance of these simulations in defining criteria for experimental measurements is discussed.

[en] The pulse height weighting integration method for measuring H' (0.07) using a plastic scintillator has been developed through Monte Carlo simulations and laboratory tests. In order to design an optimal detector configuration, the parameters of input-window thickness and plastic scintillator thickness were investigated by EGS4 for their influences on the energy response for electrons. Based on the calculated deposited spectra in the plastic scintillator for electrons with various incident energies, a weighting function W(E), folded with the deposited energy spectra, was introduced in order to obtain a flat energy response in the low energy range. A constant response within ±3% was confirmed, by calculation, for electrons with energy >0.15 MeV. In addition, a preliminary experiment was performed using three beta sources (⁹⁰Sr-⁹⁰Y, ¹⁴⁷Pm, ²⁰⁴Tl) and the energy response within ±6% for beta rays with the maximum energy >0.22 MeV was obtained. Some factors causing uncertainties in the measurements are also discussed in this article. (authors)

[en] The effect of differential divertor biasing on the outer/inner divertor asymmetry is investigated using a one-dimensional (1D) model in which the drift flow and ballooning-like transport are included. The simulation results show that (i) the outer/inner divertor asymmetries change with the applied divertor biasing, (ii) the change in divertor asymmetries induced by differential divertor biasing depends on the sign of the applied electric potential, (iii) the divertor asymmetries approach constant values with further increasing the positive divertor biasing or with decreasing the negative divertor biasing, (iv) differential divertor biasing can control the divertor asymmetry more effectively in the high recycling regime than in the low recycling regime. In addition, the effects of the E-vector x B-vector drift and ballooning-like transport on the variation in divertor asymmetry induced by differential divertor biasing are also discussed in this paper.

[en] A square lattice directed path confined to a wedge with vertex angle α exerts an entropic force F_α on the wedge. We show that this is a repulsive force of magnitude F_α = [(1 + cot²α)/(1 + cotα)²] log(cotα), if 0≤α<π/4 and F_α = 0, if π/4 ≤α≤π/2. This force is determined by examining the combinatorial properties of the directed path and by determining the exact entropic contribution to the free energy in the limit as the path length goes to infinite

[en] The origin of the two-peak photoemission and inverse-photoemission spectra in Ce and its pnictide compounds (CeP, CeSb, and CeN) is investigated with ab initio total-energy self-consistent supercell energy-band and molecular-cluster approaches to represent physically the competing mechanisms involved in d or f electron screening (antiscreening in the case of inverse photoemission) of the local 4f electron excitations. Good agreement with experiment is obtained in all cases including the ''anomalous'' case of CeN

[en] Highlights: • A theoretical analysis method is employed to solve the reverse flow problem. • The effects of reducing heat transfer capacity of the ascending section are analyzed. • The method is proposed to solve the reverse flow problem. The single-phase reverse flow problem of the parallel U-tubes of the steam generator (SG) reduces the natural circulation capacity of the system and negatively affects the safety of the reactor. In response to these issues, a theoretical analysis method verified with the experimental data is used to reveal the key factors (the heat transfer in the ascending section) affecting the single-phase reverse flow of the parallel U-tubes in SG. On this basis, we investigate the possibility of relieving the problem of single-phase reverse flow by reducing the heat transfer capacity of the ascending section under low flow conditions. Compared with other factors, the critical mass flow rate (CMFR) of reverse flow can be effectively reduced by which is useful for delaying the occurrence of the reverse flow. These research results can provide relevant theoretical support for solving the problem of the reverse flow.

[en] The molecular structure as well as crystallographic data for a new octamolybdate-supported copper(I) complex have been presented in detail

[en] In this paper the Trichel pulse regime of corona discharge in airflows is numerically studied with a two-dimensional model. The model is based on the hydrodynamic drift–diffusion approximation, taking into consideration the flow of the air in the discharge gap. Both transverse and longitudinal airflows under different conditions have been investigated. The influences of airflows on the characteristics of the Trichel pulses were clearly observed and analysed. The simulation results proved to be compatible with experimental analysis reported in the literature. (paper)

[en] The criteria for merging shock waves formed by optical breakdowns on the surface of solids have been investigated. Targets made of different materials were successively irradiated by two CO₂-laser pulses with energies up to 200 J and a duration of ∼1 μs. It is shown that the criteria under consideration can be applied to different targets and irradiation regimes and make it possible to calculate the parameters of repetitively pulsed laser radiation that are necessary to generate low-frequency sound and ultrasound in air.