General solution of the Dirac equation for quasi-two-dimensional electrons

The general solution of the Dirac equation for quasi-two-dimensional electrons confined in an asymmetric quantum well, is found. The energy spectrum of such a system is exactly calculated using special unitary operator and is shown to depend on the electron spin polarization. This solution contains free parameters, whose variation continuously transforms one known particular solution into another. As an example, two different cases are considered in detail: electron in a deep and in a strongly asymmetric shallow quantum well. The effective mass renormalized by relativistic corrections and Bychkov–Rashba coefficients are analytically obtained for both cases. It is demonstrated that the general solution transforms to the particular solutions, found previously (Eremko et al., 2015) with the use of spin invariants. The general solution allows to establish conditions at which a specific (accompanied or non-accompanied by Rashba splitting) spin state can be realized. These results can prompt the ways to control the spin degree of freedom via the synthesis of spintronic heterostructures with the required properties.     

Artificial Photosynthesis at Dynamic Self‐Assembled Interfaces in Water

Artificial photosynthesis is one of the big scientific challenges of today. Self‐assembled dynamic interfaces, such as vesicles or micelles, have been used as microreactors to mimic biological photosynthesis. These aggregates can help to overcome typical problems of homogeneous photocatalytic water splitting. Microheterogeneous environments organize catalyst–photosensitizer assemblies at the interface in close proximity and thus enhance intermolecular interactions. Thereby vesicles and micelles may promote photoinitiated charge separation and suppress back electron transfer. The dynamic self‐assembled interfaces solubilize non‐polar compounds and protect sensitive catalytic units and intermediates against degradation. In addition, vesicles provide compartmentation that was used to separate different redox environments needed for an overall water splitting system. This Minireview provides an overview of the applications of micellar and vesicular microheterogeneous systems for solar energy conversion by photosensitized water oxidation and hydrogen generation.     

Recent advances in artificial photosynthetic systems at Newcastle University

This review covers the most significant research done by the group of scientists working at Newcastle University during the last five years in the area of artificial photosynthesis. In particular, it tackles the aspects of light harvesting in molecular systems and solid state materials, photocatalysis in homogeneous and heterogeneous phases, and the fabrication of photoelectrochemical devices for the generation of hydrogen.     

Calculation of capillary jet

The Arbitrary Lagrangian Eulerian (ALE) framework coupled with some boundary tracking techniques is proven to be an effective method for simulation of free‐surface flows. In this paper, a special ALE framework is derived with clarification of three velocities, the notion of mesh‐frozen and field‐frozen, and the notion of tentatively inertial coordinates. A weighted integral ALE governing equations are formulated on generic coordinates and discretized with a finite element method and linear implicit time scheme. The system is solved with a discrete operator splitting technique and superposition‐based logistic parallelization. The formulation and implementation are verified through several fixed‐geometry problems and a reasonably good parallel performance is observed. Capillary jet flow is the main problem of the paper and the numerical techniques for boundary tracking are elaborated, which include an indirect boundary tracking of flux method and an iterative direct boundary tracking method. Also, a high‐order compact scheme for dynamic boundary condition and a squeeze technique for kinematic boundary condition are adopted. The axisymmetric jet breakup is studied in detail and numerical results match with the published data very well. Numerical accuracy and sensitivity are studied, including effects of element type, time scheme, compact scheme, and boundary tracking techniques. Copyright © 2010 John Wiley & Sons, Ltd.     

Strong Light‐Molecule Coupling on Plasmonic Arrays of Different Symmetry

The strong coupling of porphyrin J‐aggregates to plasmonic nanostructures of different symmetry is investigated. The nanostructures of higher symmetry show the strongest interaction with the molecular layer, suggesting that surface plasmon mode degeneracy plays an important role in the coupling efficiency. At high coupling strengths a new, weakly dispersive mode appears which has recently been predicted theoretically to be due to long‐range energy transfer between molecules mediated by surface plasmons. These findings point to new ways for optimizing strong coupling and thereby realize its full potential for molecular and material science.     

MoSe2/Co-MOF/NF复合材料的制备及电催化产氧性能

设计高效的催化剂对于电解水制氢至关重要。基于过渡金属硒化物(TMSe)的高催化活性和金属有机骨架(MOFs)的灵活结构，我们提出了一种将MOFs与TMSe复合的策略，在导电基底泡沫镍(NF)上生长的复合材料不仅继承了2种单体的优点，还有效地改善了MOFs导电性差、TMSe易团聚的缺点。MoSe₂/Co-MOF/NF在碱性溶液中展示出优异的电催化产氧活性，在电流密度为10 mA·cm^-2时其过电位仅为242 mV，塔菲尔斜率仅为50.64 mV·dec^-1。此外，该材料在碱性溶液中经1 000圈循环伏安(CV)循环测试和30 h的恒电压电解测试均表现出良好的稳定性。     

Laser spectroscopy of the rydberg states of atoms group IIB (Zn, Cd, Hg)

An investigation has been made of the³P_0,1,2-series of Zn (n=17–60), Cd (17–50), and Hg (18–60) atoms by the method of laser three-step photoionization. The energy (E_n) values and quantum defects (Δ) of these states are determined. The ionization potentials of the atoms are refined by matching the convergence of the Rydberg series. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 249–250, March–April, 2000.