Incipient Slip-Based Rotation Measurement via Visuotactile Sensing During In-Hand Object Pivoting

In typical in-hand manipulation tasks represented by object pivoting, the real-time perception of rotational slippage has been proven beneficial for improving the dexterity and stability of robotic hands. An effective strategy is to obtain the contact properties for measuring rotation angle through visuotactile sensing. However, existing methods for rotation estimation did not consider the impact of the incipient slip during the pivoting process, which introduces measurement errors and makes it hard to determine the boundary between stable contact and macro slip. This paper describes a generalized 2-d contact model under pivoting, and proposes a rotation measurement method based on the line-features in the stick region. The proposed method was applied to the Tac3D vision-based tactile sensors using continuous marker patterns. Experiments show that the rotation measurement system could achieve an average static measurement error of 0.17 degree and an average dynamic measurement error of 1.34 degree. Besides, the proposed method requires no training data and can achieve real-time sensing during the in-hand object pivoting.Comment: 7 pages, 9 figures, submitted to ICRA 202

Systemic delivery of siRNA nanoparticles targeting RRM2 suppresses head and neck tumor growth

Systemic delivery of siRNA to solid tumors remains challenging. In this study, we investigated the systemic delivery of a siRNA nanoparticle targeting ribonucleotide reductase subunit M2 (RRM2), and evaluated its intratumoral kinetics, efficacy and mechanism of action. Knockdown of RRM2 by an RNAi mechanism strongly inhibited cell growth in head and neck squamous cell carcinoma (HNSCC) and non-small cell lung cancer (NSCLC) cell lines. In a mouse xenograft model of HNSCC, a single intravenous injection led to the accumulation of intact nanoparticles in the tumor that disassembled over a period of at least 3 days, leading to target gene knockdown lasting at least 10 days. A four-dose schedule of siRNA nanoparticle delivering RRM2 siRNA targeted to HNSCC tumors significantly reduced tumor progression by suppressing cell proliferation and inducing apoptosis. These results show promise for the use of RRM2 siRNA-based therapy for HNSCC and possibly NSCLC

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Design of a Single-Layer ±45° Dual-Polarized Directional Array Antenna for Millimeter Wave Applications

A single-layer ±45° dual-polarized directional array antenna for millimeter wave (mm-wave) applications is designed in this communication. Based on the theory of orthogonal circularly polarized (CP) wave multiplexing, two ports of a series-fed dual CP array are fed with equal amplitudes, and the array can radiate a linearly polarized wave with ±45° polarization orientations through the adjustment of the feeding phase difference. As the two ports of the series-fed array are simultaneously excited, the antenna can achieve directional radiation. In addition, the cross-polarization level of the array can be effectively suppressed by placing two series-fed arrays side by side. A prototype of the designed array antenna operating at 30 GHz is fabricated and measured; the working bandwidth of the proposed antenna is approximately 3.5%. Owing to its simple structure and directional radiation, the proposed antenna array is a competitive candidate for mm-wave applications

Thermal characterization of phase difference among the LP modes in two-mode fibers based on numerical approach

In this work, we present the use of stochastic parallel gradient descent (SPGD) method for determination of thermal characteristic of the phases of LP11o and LP11e modes in relative to LP01 mode in two-mode fibers. Based on the output beam of the fiber, the composition of mode intensity and the respective phase are numerically determined. The findings indicate that modal phases of LP11o and LP11e linearly vary with increasing temperature. Their thermal sensitivities of LP11o and LP11e modes in relative with LP01 mode are determined. © 2020 Elsevier Gmb

Making ultrafine and highly-dispersive multimetallic nanoparticles in three-dimensional graphene with supercritical fluid as excellent electrocatalyst for oxygen reduction reaction

Three-dimensional (3D) graphene showed an advanced support for designing porous electrode materials due to its high specific surface area, large pore volume, and excellent electronic property. However, the electrochemical properties of reported porous electrode materials still need to be improved further. The current challenge is how to deposit desirable nanoparticles (NPs) with controllable structure, loading and composition in 3D graphene while maintaining the high dispersion. Herein, we demonstrate a modified supercritical fluid (SCF) technique to address this issue by controlling the SCF system. Using this superior method, a series of Pt-based/3D graphene materials with the ultrafine-sized, highly dispersive and controllable composition multimetallic NPs were successfully synthesized. Specifically, the resultant Pt40Fe60/3D graphene showed a significant enhancement in electrocatalytic performance for the oxygen reduction reaction (ORR), including a factor of 14.2 enhancement in mass activity (1.70 A mgPt-1), a factor of 11.9 enhancement in specific activity (1.55 mA cm-2), and higher durability compared with that of Pt/C catalyst. After careful comparison, the Pt40Fe60/3D graphene catalyst shows the higher ORR activity than most of the reported similar 3D graphene-based catalysts. The successful synthesis of such attractive materials by this method also paves the way to develop 3D graphene in widespread applications

Enhanced Optical Delay Line in Few-Mode Fiber Based on Mode Conversion Using Few-Mode Fiber Bragg Gratings

In this paper, we proposed an optical delay system based on a segment of few-mode fiber (FMF) and two FMF Bragg gratings (FMFBGs). The FMFBGs at both the ends of the FMF segment that serve as selective mode converters enable the pulse stream to double pass the FMF segment twice via access to the optical path length on LP11 mode in the FMF. The induced time delay by the proposed system is approximately four times the time delay of a single pass in the FMF segment. The proposed system has opened up a new horizon in the optical buffering technology for an optical communication system