Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.

Imaging field-tuned quantum Hall broken-symmetry orders and the quantum Hall conducting channel in a charge-neutral graphene/WSe_(2) heterostructure

The zeroth Landau level(0LL)in graphene has emerged as a flat band platform in which distinct many-body phases can be explored with unprecedented control by simply tuning the strength and/or direction of the magnetic field.A rich set of quantum Hall ferromagnetic phases with different lattice-scale symmetry-breaking orders are predicted to be realized in high magnetic fields when the 0LL in graphene is half-filled.Here we report on a field-tuned continuous phase transition of different valley orderings in a quantum Hall ferromagnetic phase of charge-neutral graphene on insulating tungsten diselenide(WSe_(2)).The phase transition is clearly revealed by an anomalous field-dependent energy gap in the half-filled 0LL.Using atomic resolution imaging of electronic wavefunctions during the phase transition,we unexpectedly observe the microscopic signatures of fieldtuned continuous-varied valley polarization and valley inversion,which are beyond current theoretical predictions.Moreover,the quantum Hall conducting channel of the graphene is directly imaged when the substrate(WSe_(2))introduces band bending of the 0LL.

Artistic Augmentation of Photographs with Droplets

Artistic augmentation of photographs with water droplets aims at generating aesthetic yet realistic images, and thus differs from traditional augmented reality in two aspects. One difference lies in the adoption of a new image as the environment map in order to render reflected or refracted effects on the surface of inserted water droplets. The other difference is in modeling of water droplets including hanging droplets and resting droplets. These differences raise two research challenges:(1) how to adjust the brightness and colors of the new environment map to maintain visual consistency between the new environment map and the original input image;(2) how to model hanging and resting droplets aesthetically. This paper proposes a framework that addresses these two challenges and demonstrates the effectiveness of our framework by generating example augmented images.

Local measurements of tunneling magneto-conductance oscillations in monolayer, Bernal-stacked bilayer, and ABC-stacked trilayer graphene

Shubnikov-de Haas oscillations are the most well-known magneto-oscillations in transport measurements. They are caused by Landau quantization of two-dimensional(2D) electron systems in the presence of a magnetic field. Here we demonstrate that a scanning tunneling microscope(STM) can locally measure similar magneto-oscillations in 2D systems. In Landau level spectroscopy measurements with fine magnetic-field increments, we observed fixed-energy magnetic-field-dependent oscillations of the local density of states. From the measured tunneling magneto-conductance oscillations acquired by STM, energymomentum dispersions and Berry phases of a monolayer, Bernal-stacked bilayer, and ABC-stacked trilayer graphene were obtained. The reported method is applicable to a wide range of materials because it can obtain the magneto-oscillations of 2D systems larger than the magnetic length;importantly, it also requires no gate electrode.