LATITUDE: Robotic Global Localization with Truncated Dynamic Low-pass Filter in City-scale NeRF

Neural Radiance Fields (NeRFs) have made great success in representing complex 3D scenes with high-resolution details and efficient memory. Nevertheless, current NeRF-based pose estimators have no initial pose prediction and are prone to local optima during optimization. In this paper, we present LATITUDE: Global Localization with Truncated Dynamic Low-pass Filter, which introduces a two-stage localization mechanism in city-scale NeRF. In place recognition stage, we train a regressor through images generated from trained NeRFs, which provides an initial value for global localization. In pose optimization stage, we minimize the residual between the observed image and rendered image by directly optimizing the pose on tangent plane. To avoid convergence to local optimum, we introduce a Truncated Dynamic Low-pass Filter (TDLF) for coarse-to-fine pose registration. We evaluate our method on both synthetic and real-world data and show its potential applications for high-precision navigation in large-scale city scenes. Codes and data will be publicly available at https://github.com/jike5/LATITUDE.Comment: 7 pages, 6 figures, submitted to ICRA 202

Large-area, freestanding single-crystal gold of single nanometer thickness

Two-dimensional single-crystal metals are highly sought after for next-generation technologies. Here, we report large-area (>10^4 {\mu}m2), single-crystal two-dimensional gold with thicknesses down to a single-nanometer level, employing an atomic-level-precision chemical etching approach. The ultrathin thickness and single-crystal quality endow two-dimensional gold with unique properties including significantly quantum-confinement-augmented optical nonlinearity, low sheet resistance, high transparency and excellent mechanical flexibility. By patterning the two-dimensional gold into nanoribbon arrays, extremely-confined near-infrared plasmonic resonances are further demonstrated with quality factors up to 5. The freestanding nature of two-dimensional gold allows its straightforward manipulation and transfer-printing for integration with other structures. The developed two-dimensional gold provides an emerging platform for fundamental studies in various disciplines and opens up new opportunities for applications in high-performance ultrathin optoelectronic, photonic and quantum devices

Antioxidant Activity In Vivo and In Vitro of Two Feruloyl Oligosaccharides Preparations Produced from Wheat Bran and Fermented by Aureobasidium pullulans

The antioxidant functions of two feruloyl oligosaccharide (FO1 and FO2) were investigated in vivo and in vitro. Effects of FO1 and FO2 on hemolysis of rat red blood cell (RBC) and malondialdehyde (MDA) formation in rat liver homogenate and rat liver mitochondria in vitro were studied. Hemolysis of rat RBC and MDA formation in rat liver homogenate and rat liver mitochondria were inhibited in a dosage-dependent manner by FO1 and FO2 in the tested concentration range of 0.5 to 10 mg/mL. The results showed that FO1 and FO2 had antioxidative activity in vitro, and the effect of FO2 was better than that of FO1. With increasing dosage, FO1 and FO2 could increase the activity of SOD and GSH-Px in serum of S180 tumor-bearing mice, reduce the level of MDA, and thus improve the activity of the antioxidant in vivo. When the dosage reached 250 mg/kg/d, FO2 was more likely to improve the capabilities of the antioxidants of tumor-burdened mice than were 5-FU and FO1 in vivo. Thus, these oligosaccharides may be used as functional biological materials produced from fermented lignocellulose of WB