1,555 research outputs found
EVOLUTION OF THE NORTHERN ALXA BLOCK IN THE PALEOZOIC: CONSTRAINTS FROM GEOCHRONOLOGY, GEOCHEMICAL CHARACTERISTICS AND ZIRCON HF ISOTOPES OF GRANITOIDS
The Alxa block is situated to the south of the CAOB, situated to the east of the Tarim block and west of the NCC. Voluminous intrusive and extrusive rocks outcrop in the northern Alxa block and adjacent southern CAOB. Most of them are thought to be related to the closure of the Paleo-Asia Ocean and subsequent collision [Wu, 1993; Wu et al., 1998; Zhang et al., 2013; Dan et al., 2016].The Alxa block is situated to the south of the CAOB, situated to the east of the Tarim block and west of the NCC. Voluminous intrusive and extrusive rocks outcrop in the northern Alxa block and adjacent southern CAOB. Most of them are thought to be related to the closure of the Paleo-Asia Ocean and subsequent collision [Wu, 1993; Wu et al., 1998; Zhang et al., 2013; Dan et al., 2016]
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Revealing of the Activation Pathway and Cathode Electrolyte Interphase Evolution of Li-Rich 0.5Li2MnO3·0.5LiNi0.3Co0.3Mn0.4O2 Cathode by in Situ Electrochemical Quartz Crystal Microbalance.
The first-cycle behavior of layered Li-rich oxides, including Li2MnO3 activation and cathode electrolyte interphase (CEI) formation, significantly influences their electrochemical performance. However, the Li2MnO3 activation pathway and the CEI formation process are still controversial. Here, the first-cycle properties of xLi2MnO3·(1- x) LiNi0.3Co0.3Mn0.4O2 ( x = 0, 0.5, 1) cathode materials were studied with an in situ electrochemical quartz crystal microbalance (EQCM). The results demonstrate that a synergistic effect between the layered Li2MnO3 and LiNi0.3Co0.3Mn0.4O2 structures can significantly affect the activation pathway of Li1.2Ni0.12Co0.12Mn0.56O2, leading to an extra-high capacity. It is demonstrated that Li2MnO3 activation in Li-rich materials is dominated by electrochemical decomposition (oxygen redox), which is different from the activation process of pure Li2MnO3 governed by chemical decomposition (Li2O evolution). CEI evolution is closely related to Li+ extraction/insertion. The valence state variation of the metal ions (Ni, Co, Mn) in Li-rich materials can promote CEI formation. This study is of significance for understanding and designing Li-rich cathode-based batteries
The jumping mechanism of flea beetles (Coleoptera, Chrysomelidae, Alticini), its application to bionics and preliminary design for a robotic jumping leg
Flea beetles (Coleoptera, Chrysomelidae, Galerucinae, Alticini) are a hyperdiverse group of organisms with approximately 9900 species worldwide. In addition to walking as most insects do, nearly all the species of flea beetles have an ability to jump and this ability is commonly understood as one of the key adaptations responsible for its diversity. Our investigation of flea beetle jumping is based on high-speed filming, micro- CT scans and 3D reconstructions, and provides a mechanical description of the jump. We reveal that the flea beetle jumping mechanism is a catapult in nature and is enabled by a small structure in the hind femur called an ‘elastic plate’ which powers the explosive jump and protects other structures from potential injury. The explosive catapult jump of flea beetles involves a unique ‘high-efficiency mechanism’ and ‘positive feedback mechanism’. As this catapult mechanism could inspire the design of bionic jumping limbs, we provide a preliminary design for a robotic jumping leg, which could be a resource for the bionics industry
Spin Injection and Inverse Edelstein Effect in the Surface States of Topological Kondo Insulator SmB6
There has been considerable interest in exploiting the spin degrees of
freedom of electrons for potential information storage and computing
technologies. Topological insulators (TI), a class of quantum materials, have
special gapless edge/surface states, where the spin polarization of the Dirac
fermions is locked to the momentum direction. This spin-momentum locking
property gives rise to very interesting spin-dependent physical phenomena such
as the Edelstein and inverse Edelstein effects. However, the spin injection in
pure surface states of TI is very challenging because of the coexistence of the
highly conducting bulk states. Here, we experimentally demonstrate the spin
injection and observe the inverse Edelstein effect in the surface states of a
topological Kondo insulator, SmB6. At low temperatures when only surface
carriers are present, a clear spin signal is observed. Furthermore, the
magnetic field angle dependence of the spin signal is consistent with
spin-momentum locking property of surface states of SmB6.Comment: 15 pages, 5 figures, Accepted to Nature Communications (In Press
Attention Mechanisms in Computer Vision: A Survey
Humans can naturally and effectively find salient regions in complex scenes.
Motivated by this observation, attention mechanisms were introduced into
computer vision with the aim of imitating this aspect of the human visual
system. Such an attention mechanism can be regarded as a dynamic weight
adjustment process based on features of the input image. Attention mechanisms
have achieved great success in many visual tasks, including image
classification, object detection, semantic segmentation, video understanding,
image generation, 3D vision, multi-modal tasks and self-supervised learning. In
this survey, we provide a comprehensive review of various attention mechanisms
in computer vision and categorize them according to approach, such as channel
attention, spatial attention, temporal attention and branch attention; a
related repository https://github.com/MenghaoGuo/Awesome-Vision-Attentions is
dedicated to collecting related work. We also suggest future directions for
attention mechanism research.Comment: 27 pages, 9 figure
An abnormal bone marrow microenvironment contributes to hematopoietic dysfunction in Fanconi anemia
Fanconi anemia is a complex heterogeneous genetic disorder with a high incidence of bone marrow failure, clonal evolution to acute myeloid leukemia and mesenchymal-derived congenital anomalies. Increasing evidence in Fanconi anemia and other genetic disorders points towards an interdependence of skeletal and hematopoietic development, yet the impact of the marrow microenvironment in the pathogenesis of the bone marrow failure in Fanconi anemia remains unclear. Here we demonstrated that mice with double knockout of both Fancc and Fancg genes had decreased bone formation at least partially due to impaired osteoblast differentiation from mesenchymal stem/progenitor cells. Mesenchymal stem/progenitor cells from the double knockout mice showed impaired hematopoietic supportive activity. Mesenchymal stem/progenitor cells of patients with Fanconi anemia exhibited similar cellular deficits, including increased senescence, reduced proliferation, impaired osteoblast differentiation and defective hematopoietic stem/progenitor cell supportive activity. Collectively, these studies provide unique insights into the physiological significance of mesenchymal stem/progenitor cells in supporting the marrow microenvironment, which is potentially of broad relevance in hematopoietic stem cell transplantation
Lemur: Harmonizing Natural Language and Code for Language Agents
We introduce Lemur and Lemur-Chat, openly accessible language models
optimized for both natural language and coding capabilities to serve as the
backbone of versatile language agents. The evolution from language chat models
to functional language agents demands that models not only master human
interaction, reasoning, and planning but also ensure grounding in the relevant
environments. This calls for a harmonious blend of language and coding
capabilities in the models. Lemur and Lemur-Chat are proposed to address this
necessity, demonstrating balanced proficiencies in both domains, unlike
existing open-source models that tend to specialize in either. Through
meticulous pre-training using a code-intensive corpus and instruction
fine-tuning on text and code data, our models achieve state-of-the-art averaged
performance across diverse text and coding benchmarks among open-source models.
Comprehensive experiments demonstrate Lemur's superiority over existing
open-source models and its proficiency across various agent tasks involving
human communication, tool usage, and interaction under fully- and partially-
observable environments. The harmonization between natural and programming
languages enables Lemur-Chat to significantly narrow the gap with proprietary
models on agent abilities, providing key insights into developing advanced
open-source agents adept at reasoning, planning, and operating seamlessly
across environments. https://github.com/OpenLemur/Lemu
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