Effects of edge disorder on the stability of quantum oscillations in two-dimensional coupled systems.

This paper utilizes the theory of quantum diffusion to analyze the electron probability and spreading width of a wavepacket on each layer in a two-dimensional (2D) coupled system with edge disorder, aiming to clarify the effects of edge disorder on the stability of the electron periodic oscillations in 2D coupled systems. Using coupled 2D square lattices with edge disorder as an example, we show that, the electron probability and wavepacket spreading width exhibit periodic oscillations and damped oscillations, respectively, before and after the wavepacket reaches the boundary. Furthermore, these electron oscillations exhibit strong resistance against disorder perturbation with a longer decay time in the regime of large disorder, due to the combined influences of ordered and disordered site energies in the central and edge regions. Finally, we numerically verified the universality of the results through bilayer graphene, demonstrating that this anomalous quantum oscillatory behavior is independent of lattice geometry. Our findings are helpful in designing relevant quantum devices and understanding the influence of edge disorder on the stability of electron periodic oscillations in 2D coupled systems.

High-performance asymmetric optical transmission based on coupled complementary subwavelength gratings.

Asymmetric transmission (AT) devices are fundamental elements for optical computing and information processing. We here propose an AT device consisting of a pair of coupled complementary subwavelength gratings. Different from previous works, asymmetric dielectric environment is employed for unidirectional excitation of surface plasmon polaritons (SPPs) and thus asymmetric optical transmission, and near-field coupling effect inherent in the coupled complementary structure is exploited to enhance forward transmission and AT behavior, and determine operation bandwidth as well. The influence of asymmetric dielectric environment, effect of vertical and lateral couplings, interactions of electric- and magnetic-dipole moments and the realization of Kerker conditions, are investigated in depth to unearth the AT mechanism and performance. High-performance AT with large forward transmittance of 0.96 and broad bandwidth of 174 nm is achieved at wavelength 1250 nm. Our work helps people to gain a better understanding of near-filed coupling effect in coupled complementary structures, expand their application fields, and it also offers an alternate way to high-performance AT devices.

[Determination of arsenic, antimony, mercury and selenium in different parts of Acanthopanax senticosus harms by atomic fluorescence spectrometry].

A method for the determination of arsenic, antimony, mercury and selenium in different parts (root, stem, leaf and fruit) of acanthopanax senticosus harms using hydride generation atomic fluorescence spectrometry with microwave digestion was developed. Under the optimized experimental conditions, the concentration of arsenic, antimony, mercury and selenium showed a linear relationship with the fluorescence intensity. The detection limit of arsenic was 0.068 ng x mL(-1), and the RSD was 1.05%. The detection limit of antimony was 0.155 ng x mL(-1), and the RSD was 1.32%. The detection limit of mercury was 0.014 ng x mL(-1), and the RSD was 2.03%. The detection limit of selenium was 0.052 ng x mL(-1), and the RSD was 2.34%. The method was checked in terms of accuracy and precision using the standard reference substance of hair (GBW07601), and proved to be sensitive and rapid with satisfactory results. The content of arsenic, mercury and selenium is high in the leaf, and that of antimony is higher in the root than in other parts.

[Determination of trace mercury in different sorts of Chinese herbs by atomic fluorescence spectrometry with microwave digestion].

A method for the determination of trace mercury in different sorts of Chinese herbs using hydride generation atomic fluorescence spectrometry under different microwave digestion conditions was developed. Under the optimized experimental conditions, the linear equation was I(F) = 809.1 x -3.327 5, the correlation coefficient was 0.999 998,and the linear range for mercury was 0-80 ng x mL(-1). The detection limit of mercury was 0.014 ng x mL(-1) (n = 11) and the relative standard deviation was 2.03%. The recoveries for these samples were 96.8%-102.80% (n = 6) while the detection limit of the method was 1.17 ng x g(-1). The method's accuracy and precision for different sorts of Chinese herbs using the standard reference standard substance of rice (GBW08508), poplar leaf (GBW07601), and mytilus edulis (GBW08571) was checked, and the results were found to be basically consistent with the reference values. This method has been proved to be sensitive, simple and rapid with satisfactory results.