DVI-SLAM: A Dual Visual Inertial SLAM Network

Recent deep learning based visual simultaneous localization and mapping (SLAM) methods have made significant progress. However, how to make full use of visual information as well as better integrate with inertial measurement unit (IMU) in visual SLAM has potential research value. This paper proposes a novel deep SLAM network with dual visual factors. The basic idea is to integrate both photometric factor and re-projection factor into the end-to-end differentiable structure through multi-factor data association module. We show that the proposed network dynamically learns and adjusts the confidence maps of both visual factors and it can be further extended to include the IMU factors as well. Extensive experiments validate that our proposed method significantly outperforms the state-of-the-art methods on several public datasets, including TartanAir, EuRoC and ETH3D-SLAM. Specifically, when dynamically fusing the three factors together, the absolute trajectory error for both monocular and stereo configurations on EuRoC dataset has reduced by 45.3% and 36.2% respectively.Comment: 7 pages, 3 figure

New Measurement Technique for Complex Permittivity in Millimeter-Wave Band Using Simple Rectangular Waveguide Adapters

This research presents a novel methodology for measuring the complex permittivity of a material under test (MUT) in a millimeter-wave (mmWave) band by using two rectangular waveguide adapters. Contrary to the conventional Nicolson-Ross-Weir (NRW) method, the proposed complex permittivity measurement method does not require a material fabrication process for exact MUT insertion into a waveguide. In our complex permittivity measurement, simple commercial waveguide adapters are employed instead of large flange structures. The proposed complex permittivity measurement of a non-destructive MUT is achieved by combining the NRW method, the Gaussian weighting moving average filtering technique, a full-wave electromagnetic analysis, and an optimization technique. Furthermore, the proposed methodology is validated by fabricating a Teflon-based MUT and by measuring the complex permittivity of the MUT in the Ka band (26.5–40 GHz). The results indicate that the proposed methodology exhibits good agreement with the data sheet

Multi-Layer SnSe Nanoflake Field-Effect Transistors with Low-Resistance Au Ohmic Contacts

Abstract We report p-type tin monoselenide (SnSe) single crystals, grown in double-sealed quartz ampoules using a modified Bridgman technique at 920 °C. X-ray powder diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) measurements clearly confirm that the grown SnSe consists of single-crystal SnSe. Electrical transport of multi-layer SnSe nanoflakes, which were prepared by exfoliation from bulk single crystals, was conducted using back-gated field-effect transistor (FET) structures with Au and Ti contacts on SiO2/Si substrates, revealing that multi-layer SnSe nanoflakes exhibit p-type semiconductor characteristics owing to the Sn vacancies on the surfaces of SnSe nanoflakes. In addition, a strong carrier screening effect was observed in 70−90-nm-thick SnSe nanoflake FETs. Furthermore, the effect of the metal contacts to multi-layer SnSe nanoflake-based FETs is also discussed with two different metals, such as Ti/Au and Au contacts

Ion Gel‐Gated Quasi‐Solid‐State Vertical Organic Electrochemical Transistor and Inverter

Abstract Parallel‐type organic electrochemical transistors (p‐OECTs) with aqueous electrolyte gate dielectrics have been widely studied for transducing biological signals into electrical signals. However, aqueous liquid electrolyte‐based p‐OECTs suffer from poor device stability, low transconductance (gm), and limited applications. In this study, a quasi‐solid‐state ion gel‐gated vertical‐type OECT (v‐OECT) and NOT logic gate are successfully demonstrated by combining both p‐type and n‐type v‐OECTs for the first time. Indacenodithiophene (IDT) polymers with alkyl (PIDTC16‐BT) and oligoethylene glycol (OEG) substituents (PIDTPEG‐BT) are studied as a channel material, and an ionic liquid in a crosslinked polymer matrix is adopted as a quasi‐solid electrolyte. Compared to aqueous devices, an enlarged electrochemical window and improved operational stability are observed. Notably, the v‐OECTs have a significantly larger channel area (50 × 50 µm2) and shorter channel length (≈30 nm), yielding a dramatically increased gm. As‐spun PIDTC16‐BT films exhibit a noticeably higher gm of 72.8 mS than that of previous p‐OECTs along with superior device stability, despite a low volumetric capacitance. In the case of v‐OECTs, face‐on intermolecular packing is required to increase the carrier transport in a vertical direction. Logic gates are successfully demonstrated using p‐ and n‐type v‐OECTs, suggesting the potential of OECT‐based next‐generation electronics