603 research outputs found
Development and test of an open source autonomous sailing robot with accessibility, generality and extendability
This paper introduces the design of an open source autonomous sailing robot with emphasis on its accessibility, generality and extendability. To meet such requirements, a generic control box connecting an Arduino board and a Raspberry Pi computer was tailor-made so as to host the robot operating system (ROS) and to interact with versatile sensors and actuators. The goal of such a project is to create an accessible, generic and expendable platform of autonomous sailboats for wider education and research publicity and engagement. Autonomous sailing test for the developed sailboat was also conducted to validate its design
2,4-Disulfanyl-6-[(E)-(2-sulfanylbenzyl)iminomethyl]phenol
In the title compound, C14H13NOS3, the dihedral angle between the benzene rings is 73.26 (5)° and an intramolecular O—H⋯N hydrogen bond occurs
Diaquabis[2-(4-bromophenyl)acetato]bis(N 4,N 4-dimethylpyridin-4-amine)copper(II)
In the title compound, [Cu(C8H6BrO2)2(C7H10N2)2(H2O)2], the CuII atom (site symmetry ) adopts a Jahn–Teller-distorted trans-CuN2O4 octahedral coordination, with the aqua O atoms in axially extended sites. An intramolecular O—H⋯O hydrogen bond helps to establish the conformation and an intermolecular O—H⋯O hydrogen bond is seen in the crystal packing
AEGIS-Net: Attention-guided Multi-Level Feature Aggregation for Indoor Place Recognition
We present AEGIS-Net, a novel indoor place recognition model that takes in
RGB point clouds and generates global place descriptors by aggregating
lower-level color, geometry features and higher-level implicit semantic
features. However, rather than simple feature concatenation, self-attention
modules are employed to select the most important local features that best
describe an indoor place. Our AEGIS-Net is made of a semantic encoder, a
semantic decoder and an attention-guided feature embedding. The model is
trained in a 2-stage process with the first stage focusing on an auxiliary
semantic segmentation task and the second one on the place recognition task. We
evaluate our AEGIS-Net on the ScanNetPR dataset and compare its performance
with a pre-deep-learning feature-based method and five state-of-the-art
deep-learning-based methods. Our AEGIS-Net achieves exceptional performance and
outperforms all six methods.Comment: Accepted by 2024 IEEE International Conference on Acoustics, Speech
and Signal Processing (ICASSP 2024
Origin of the Oligocene Tuolangla porphyry-skarn Cu-W-Mo deposit in Lhasa terrane, southern Tibet
Although some porphyry-skarn deposits occur in post-collisional extensional settings, the post-collisional deposits remain poorly understood. Here the authors describe the igneous geology, and mineralization history of Tuolangla, a newly-discovered porphyry-skarn Cu-W-Mo deposit in southern Tibet that belongs to the post-collisional class. The deposit is associated with Lower Cretaceous Bima Formation. It was intruded by granodiorite porphyry intrusions at about 23.1 Ma. Field investigation indicated that mineralization is spatially and temporally associated with granodiorite porphyry. Molybdenite yielded a Re-Os weighted mean age of 23.5 +/- 0.3 Ma and is considered to represent the age of skarn mineralization at the deposit. The delta S-34 values of sulfides, concentrated in a range between 0.6 parts per thousand to 3.4 parts per thousand, show that the sulfur has a homogeneous source with characteristics of magmatic sulfur. The Pb isotopic compositions of sulfides indicate that ore-forming metal materials were derived from the mantle and ancient crust. The granodiorite porphyry displays high SiO2 (68.78%-69.75%) and K2O (3.40%-3.56%) contents, and relatively lower Cr (2.4x10(-6) -4.09x10(-6) ), Ni (2.79x10(-6)-3.58x10(-6)) contents, and positive epsilon(Hf)(t) values (7.7-12.9) indicating that the mineralization porphyry was derived from the partial melting of juvenile lower crust. The Tuolangla deposit is located in the central part of Zedang terrane. This terrane was once considered an ancient terrane. This terrane is in tectonic contact with Cretaceous ophiolitic rocks to its south and Mesozoic continental margin arc volcanics and intrusions of the Gangdese batholith of the Lhasa terrane to its north. Thus, the authors proposed that the Oligocene porphyry skarn Cu-W-Mo mineralization is probably associated with the Zedang terrane. This finding may clarify why the Oligocene (about 23 Ma) deposits are found only in the Zedang area and why mineralization types of the Oligocene mineralization are considerably different from those of the Miocene (17-14 Ma) mineralization. (C) 2020 China Geology Editorial Office
Sugar transporter engineering in yeast to enable simultaneous co-utilization of sugars prevalent in cellulosic hydrolysates
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Long-term Continuous Energy Injection in the Afterglow of GRB 060729
A long plateau phase and an amazing brightness have been observed in the Xray
afterglow of GRB 060729. This peculiar light curve is likely due to long-term
energy injection in external shock. Here we present a detailed numerical study
on the energy injection process of magnetic dipole radiation from a strongly
magnetized millisecond pulsar and model the multi-band afterglow observations.
It is found that this model can successfully explain the long plateaus in the
observed X-ray and optical afterglow light curves. The sharp break following
the plateaus should be due to the rapid decline of the emission power of the
central pulsar. At an even late time (~5*10^6s), an obvious jet break appears,
which implies a relatively large half opening angle of theta~0.3 for the GRB
ejecta. Due to the energy injection, the Lorentz factor of the outflow is still
larger than two 10^7s post the GRB trigger, making the X-ray afterglow of this
burst detectable by Chandra even 642 days after the burst.Comment: 7 pages, 3 figures, accepted by RA
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