Gas pressure sintering of BN/Si3N4 wave-transparent material with Y2O3–MgO nanopowders addition

AbstractBN/Si3N4 ceramics performed as wave-transparent material in spacecraft were fabricated with boron nitride powders, silicon nitride powders and Y2O3–MgO nanopowders by gas pressure sintering at 1700°C under 6MPa in N2 atmosphere. The effects of Y2O3–MgO nanopowders on densification, phase evolution, microstructure and mechanical properties of BN/Si3N4 material were investigated. The addition of Y2O3–MgO nanopowders was found beneficial to the mechanical properties of BN/Si3N4 composites. The BN/Si3N4 ceramics with 8wt% Y2O3–MgO nanopowders showed a relative density of 80.2%, combining a fracture toughness of 4.6MPam1/2 with an acceptable flexural strength of 396.5MPa

AnyDoor: Zero-shot Object-level Image Customization

This work presents AnyDoor, a diffusion-based image generator with the power to teleport target objects to new scenes at user-specified locations in a harmonious way. Instead of tuning parameters for each object, our model is trained only once and effortlessly generalizes to diverse object-scene combinations at the inference stage. Such a challenging zero-shot setting requires an adequate characterization of a certain object. To this end, we complement the commonly used identity feature with detail features, which are carefully designed to maintain texture details yet allow versatile local variations (e.g., lighting, orientation, posture, etc.), supporting the object in favorably blending with different surroundings. We further propose to borrow knowledge from video datasets, where we can observe various forms (i.e., along the time axis) of a single object, leading to stronger model generalizability and robustness. Extensive experiments demonstrate the superiority of our approach over existing alternatives as well as its great potential in real-world applications, such as virtual try-on and object moving. Project page is https://damo-vilab.github.io/AnyDoor-Page/.Comment: CVPR202

BN Nanoparticles/Si₃N₄Wave-Transparent Composites with High Strength and Low Dielectric Constant

Si3N4wave-transparent composites with different volume content of BN nanoparticles (BNnp/Si3N4) were prepared by gas pressure sintering at 1800°C in N2atmosphere. The effects of BN nanoparticles on the dielectric and mechanical properties of BNnp/Si3N4composites were investigated. The results showed that the addition of the BN nanoparticles improved the dielectric properties of BNnp/Si3N4composites effectively and decreased the mechanical properties. When the volume content of BN nanoparticles was 10%, the dielectric constant and dielectric loss tangent were 4.31 and 0.006, respectively, and the bending strength and fracture toughness still reached 198.9 MPa and 3.36 MPa·m1/2. The high mechanical properties of BNnp/Si3N4composites with 10% BN nanoparticles were attributed to homogeneously dispersed BN nanoparticles which were embedded in the pores formed by the rod-likeβ-Si3N4.</jats:p

Simulation on thermal load gradient mitigation with auxiliary multi-seeds amplification in fiber amplifier

A technique that employs auxiliary multi-seeds for mitigating the inhomogeneous of thermal load in Yb-doped double cladding amplifier is presented and verified in simulation. The results shows this technique can reduce the thermal load gradient by a significant ratio, thus has potential application in high power amplifiers