657 research outputs found
Enhanced thermopower in an intergrowth cobalt oxide LiNaCoO
We report the measurements of thermopower, electrical resistivity and thermal
conductivity in a complex cobalt oxide LiNaCoO, whose
crystal structure can be viewed as an intergrowth of the O3 phase of
LiCoO and the P2 phase of NaCoO along the c axis. The
compound shows large room-temperature thermopower of 180 V/K, which
is substantially higher than those of LiCoO and NaCoO.
The figure of merit for the polycrystalline sample increases rapidly with
increasing temperature, and it achieves nearly 10 K at 300 K,
suggesting that LiNaCoO system is a promising candidate for
thermoelectric applications.Comment: Submitted to AP
Heuristic-based Incremental Probabilistic Roadmap for Efficient UAV Exploration in Dynamic Environments
Autonomous exploration in dynamic environments necessitates a planner that
can proactively respond to changes and make efficient and safe decisions for
robots. Although plenty of sampling-based works have shown success in exploring
static environments, their inherent sampling randomness and limited utilization
of previous samples often result in sub-optimal exploration efficiency.
Additionally, most of these methods struggle with efficient replanning and
collision avoidance in dynamic settings. To overcome these limitations, we
propose the Heuristic-based Incremental Probabilistic Roadmap Exploration
(HIRE) planner for UAVs exploring dynamic environments. The proposed planner
adopts an incremental sampling strategy based on the probabilistic roadmap
constructed by heuristic sampling toward the unexplored region next to the free
space, defined as the heuristic frontier regions. The heuristic frontier
regions are detected by applying a lightweight vision-based method to the
different levels of the occupancy map. Moreover, our dynamic module ensures
that the planner dynamically updates roadmap information based on the
environment changes and avoids dynamic obstacles. Simulation and physical
experiments prove that our planner can efficiently and safely explore dynamic
environments
Changes of Myogenic Reactive Oxygen Species and Interleukin-6 in Contracting Skeletal Muscle Cells
The aim of this study was to measure changes in myotube reactive oxygen species (ROS) and the production of interleukin (IL)-6 in electrically stimulated mouse C2C12 skeletal muscle cells. After five days of differentiation, myotubes were stimulated using an electrical stimulator set at 45 V at a frequency of 5 Hz, with a pulse width of 20 ms. Acute stimulations were performed for 45, 60, 75, 90, or 120 min in each dish. ROSs were detected in the extracted cells directly using a fluorescent probe. IL-6 mRNA expression in C2C12 myotubes and IL-6 concentration in C2C12 myotube supernatants were determined using real-time PCR and ELISA, respectively. Compared with control cells, ROS generation was significantly increased at 45 min after the onset of stimulation (P < 0.01) and continued to increase, reaching a maximum at 120 min. IL-6 mRNA expression and IL-6 concentration in C2C12 cells were significantly increased after 75 min (P < 0.01) and 120 min (P < 0.05) of electrical stimulation (ES) compared with the control cells. Our data show that a specific ES intensity may modulate ROS accumulation and affect IL-6 gene expression in contracting skeletal muscle cells
Energy-efficient domain wall motion governed by the interplay of helicity-dependent optical effect and spin-orbit torque
Spin-orbit torque provides a powerful means of manipulating domain walls
along magnetic wires. However, the current density required for domain wall
motion is still too high to realize low power devices. Here we experimentally
demonstrate helicity-dependent domain wall motion by combining synchronized
femtosecond laser pulses and short current pulses in Co/Ni/Co ultra-thin film
wires with perpendicular magnetization. Domain wall can remain pinned under one
laser circular helicity while depinned by the opposite circular helicity.
Thanks to the all-optical helicity-dependent effect, the threshold current
density due to spin-orbit torque can be reduced by more than 50%. Based on this
joint effect combining spin-orbit torque and helicity-dependent laser pulses,
an optoelectronic logic-in-memory device has been experimentally demonstrated.
This work enables a new class of low power spintronic-photonic devices beyond
the conventional approach of all-optical switching or all-current switching for
data storage.Comment: 21 pages, 5 figure
Relational Learning between Multiple Pulmonary Nodules via Deep Set Attention Transformers
Diagnosis and treatment of multiple pulmonary nodules are clinically
important but challenging. Prior studies on nodule characterization use
solitary-nodule approaches on multiple nodular patients, which ignores the
relations between nodules. In this study, we propose a multiple instance
learning (MIL) approach and empirically prove the benefit to learn the
relations between multiple nodules. By treating the multiple nodules from a
same patient as a whole, critical relational information between
solitary-nodule voxels is extracted. To our knowledge, it is the first study to
learn the relations between multiple pulmonary nodules. Inspired by recent
advances in natural language processing (NLP) domain, we introduce a
self-attention transformer equipped with 3D CNN, named {NoduleSAT}, to replace
typical pooling-based aggregation in multiple instance learning. Extensive
experiments on lung nodule false positive reduction on LUNA16 database, and
malignancy classification on LIDC-IDRI database, validate the effectiveness of
the proposed method.Comment: 2020 IEEE 17th International Symposium on Biomedical Imaging (ISBI
2020
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