Publications by authors named "Zhaoxi Chen"

Article Synopsis
  • Platinum oxides are essential for various catalytic reactions but typically break down at high temperatures, limiting their applications.
  • This study discovers a two-dimensional (2D) crystalline Pt oxide with impressive thermal stability at 1,200 K, characterized by a unique honeycomb lattice structure.
  • The findings improve our understanding of Pt oxides and suggest they can function effectively in high-temperature environments, potentially altering their catalytic application.
View Article and Find Full Text PDF
Article Synopsis
  • Challenges in efficiently converting biomass-based aldehydes and alcohols to acids limit their broader application; this study presents a solution with a new catalyst.
  • The Pd/Ni(OH) catalyst achieves nearly 100% selectivity in producing 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural, yielding 97.3% at a voltage of 0.6 V under standard conditions.
  • The catalyst's effectiveness is enhanced by its unique Ni-O-Pd interfaces, which promote reaction steps, prevent nanoparticle clumping, and maintain stability over 200 hours of continuous use.
View Article and Find Full Text PDF

Neural Radiance Field (NeRF) has achieved substantial progress in novel view synthesis given multi-view images. Recently, some works have attempted to train a NeRF from a single image with 3D priors. They mainly focus on a limited field of view with a few occlusions, which greatly limits their scalability to real-world 360-degree panoramic scenarios with large-size occlusions.

View Article and Find Full Text PDF

Integrated microwave photonics (MWP) is an intriguing technology for the generation, transmission and manipulation of microwave signals in chip-scale optical systems. In particular, ultrafast processing of analogue signals in the optical domain with high fidelity and low latency could enable a variety of applications such as MWP filters, microwave signal processing and image recognition. An ideal integrated MWP processing platform should have both an efficient and high-speed electro-optic modulation block to faithfully perform microwave-optic conversion at low power and also a low-loss functional photonic network to implement various signal-processing tasks.

View Article and Find Full Text PDF

On-chip optical microresonators are essential building blocks in integrated optics. The ability to arbitrarily engineer their resonant frequencies is crucial for exploring novel physics in synthetic frequency dimensions and practical applications like nonlinear optical parametric processes and dispersion-engineered frequency comb generation. Photonic crystal ring (PhCR) resonators are a versatile tool for such arbitrary frequency engineering, by controllably creating mode splitting at selected resonances.

View Article and Find Full Text PDF

The nitrogen doping (N-doping) treatment for niobium superconducting radio-frequency (SRF) cavities is one of the key enabling technologies that support the development of more efficient future large accelerators. However, the N-doping results have diverged due to a complex chemical profile under the nitrogen-doped surface. Particularly, under industrial-scale production conditions, it is difficult to understand the underlying mechanism thus hindering performance improvement.

View Article and Find Full Text PDF

In this work, we present SceneDreamer, an unconditional generative model for unbounded 3D scenes, which synthesizes large-scale 3D landscapes from random noise. Our framework is learned from in-the-wild 2D image collections only, without any 3D annotations. At the core of SceneDreamer is a principled learning paradigm comprising: 1) an efficient yet expressive 3D scene representation, 2) a generative scene parameterization, and 3) an effective renderer that can leverage the knowledge from 2D images.

View Article and Find Full Text PDF
Article Synopsis
  • - Lithium niobate (LiNbO) is a promising material for nonlinear optics due to its strong nonlinear properties, but bulk crystals face challenges in achieving phase-matching for complex processes like high-harmonic generation (HHG).
  • - Researchers developed LiNbO metasurfaces that enhance light-matter interactions at the nanoscale, enabling efficient second-harmonic generation (SHG) and HHG, with demonstrated SHG efficiency of 5.1 × 10 cm GW and HHG reaching the 7th order with wavelengths as short as 226 nm.
  • - This advancement opens up possibilities for creating compact coherent white-light sources that can reach into the deep ultraviolet spectrum, which is valuable for various applications in
View Article and Find Full Text PDF

Poria cocos (Schw.) Wolf is a well-known edible and medicinal fungus. The polysaccharide in the sclerotium of P.

View Article and Find Full Text PDF

Radar is an extremely valuable sensing technology for detecting moving targets and measuring their range, velocity, and angular positions. When people are monitored at home, radar is more likely to be accepted by end-users, as they already use WiFi, is perceived as privacy-preserving compared to cameras, and does not require user compliance as wearable sensors do. Furthermore, it is not affected by lighting condi-tions nor requires artificial lights that could cause discomfort in the home environment.

View Article and Find Full Text PDF

Electron microscopy has been widely used in the structural analysis of proteins, pharmaceutical products, and various functional materials in the past decades. However, one fact is often overlooked that the crystal structure might be sensitive to external environments and response manners, which will bring uncertainty to the structure determination and structure-property correlation. Here, we report the atomic-level ab initio structure determinations of microcrystals by combining 3D electron diffraction (3D ED) and environmental transmission electron microscope (TEM).

View Article and Find Full Text PDF

Lithium niobate on insulator (LNOI) is an emerging photonic platform with great promise for use in future optical communications, nonlinear optics, and microwave photonics. An important integrated photonic building block, active waveguide amplifiers, however, are still missing in the LNOI platform. Here, we report an efficient and compact waveguide amplifier based on erbium-doped LNOI waveguides, achieved using a sequence of erbium-doped crystal growth, ion slicing, and lithography-based waveguide fabrication.

View Article and Find Full Text PDF

The experimental demonstration of measurement-device-independent quantum key distribution (MDI-QKD) has been widely demonstrated. Thus far, several experimental groups have implemented polarization encoding MDI-QKD but with manual polarization controllers, or polarization modulators that make circular polarization states unstable. Here, we apply an intrinsically stable polarization-modulated unit (PMU) to MDI-QKD so that Alice and Bob can modulate four BB84 polarization states, all of which can be kept stable from even the harsh environment.

View Article and Find Full Text PDF

Addressing the challenge of making ceramic thin films with the in-plane-oriented nanorods, we propose to decorate the nanorods with magnetic nanoparticles and orient them using the external magnetic field. As an illustration, the mullite thin films with embedded and oriented SiC nanorods were synthesized. The SiC nanorods were decorated with the FeO nanoparticles.

View Article and Find Full Text PDF

Precursors derived from the hydrolysis of organic or inorganic salts have been widely used to produce ceramic coatings for a broad variety of applications. When applying the liquid precursors to the substrates, it is extremely challenging to control the film uniformity and homogeneity. The rate of solvent evaporation at different locations is different, causing the viscosity variation and flows in the film.

View Article and Find Full Text PDF