Shape-predicted model of spray forming rod under scanning atomization

A model for simulating the spray forming process with scanning atomizer was developed.Models for the scanning atomization and the deposition processes were coupled together in order to obtain a new description of the spray forming process.The model,which is able to predict the shape of a spray-formed billet prepared with scanning atomizer,was established after analyzing the changes in droplet size and density distribution along the r-axis in the spray cone in scanning atomization.The effects of the two kinds of atomization were compared,showing that the scanning atomization is good for deposition.

Scanning and Splicing Atom Lithography for Self-traceable Nanograting Fabrication

Atom lithography is a unique method to fabricate self-traceable pitch standards and angle standards,but extending its structure area to millimeter-level for application is challenging.In this paper,on the one hand,we put forward a new approach to fabricate a full-covered self-traceable Cr nanograting by inserting and scanning a Dove prism in the Gaussian beam direction of atom lithography.On the other hand,we extend the structure area along the standing-wave direction by splicing two-step atom deposition.Both nanostructures manufactured via scanning atom lithography and splicing atom lithography demonstrate good pitch accuracy,parallelism,continuity,and homogeneity,which opens a new way to fabricate centimeter-level full-covered self-traceable nanograting and lays the basis for the application of square ruler and optical encoders at the nanoscale.

A dual-use probe for nano-metric photoelectric characterization using a confined light field generated by photonic crystals in the cantilever

We propose a plasmonic atomic force microscopy (AFM) probe, which takes a part of the laser beam for monitoring cantilever deflection as the excitation light source. Photonic crystal cavities are integrated near the cantilever’s free end where the laser spot locates. The transmitted light excites surface plasmon polaritons on the metal-coated tip and induces a confined hot-spot at the tip apex. Numerical simulations demonstrate that the plasmonic probe can couple a tilted, linearly polarized beam efficiently and yield a remarkable local electromagnetic enhancement with the intensity being around 21 times stronger than that of the original probe. For demonstration, we employ the plasmonic probe in electrostatic force microscopy and scanning Kelvin probe microscopy to study the impact of local light field on the photoelectric characteristics of SiO_(2) and Au nanoparticles. Compared with the original probe, obvious differences are observed in the electrostatic force gradients on SiO_(2) nanoparticles and in the surface potentials of Au nanoparticles. The plasmonic probe can enable AFM as a powerful tool for simultaneous optical, mechanical and electrical characterizations.

Methylammonium cation deficient surface for enhanced binding stability at TiO2/CH3NH3PbI3 interface

Heterojunction interfaces in perovskite solar cells play an important role in enhancing their photoelectric properties and stability. Till date, the precise lattice arrangement at TiO2/CH3NH3PbI3 heterojunction interfaces has not been investigated clearly. Here, we examined a TiO2/CH3NH3PbI3 interface and found that a heavy atomic layer exists in such interfaces, which is attributed to the vacancies of methylammonium （MA） cation groups. Further, first-principles calculation results suggested that an MA cation-deficient surface structure is beneficial for a strong heterogeneous binding between TiO2 and CH3NH3PbI3 to enhance the interface stability. Our research is helpful for further understanding the detailed interface atom arrangements and provides references for interfacial modification in perovskite solar cells.