15 research outputs found
Investigation of GaN-based dual-wavelength light-emitting diodes with p-type barriers and vertically stacked quantum wells
Designs of p-doped in quantum well (QW) barriers and specific number of vertically stacked QWs are proposed to improve the optical performance of GaN-based dual-wavelength light-emitting diodes (LEDs). Emission spectra, carrier concentration, electron current density, and internal quantum efficiency (IQE) are studied numerically. Simulation results show that the efficiency droop and the spectrum intensity at the large current injection are improved markedly by using the proposed design. Compared with the conventional LEDs, the uniform spectrum intensity of dual-wavelength luminescence is realized when a specific number of vertically stacked QWs is adopted. Suppression of electron leakage current and the promotion of hole injection efficiency could be one of the main reasons for these improvements
Language-Assisted 3D Feature Learning for Semantic Scene Understanding
Learning descriptive 3D features is crucial for understanding 3D scenes with diverse objects and complex structures. However, it is usually unknown whether important geometric attributes and scene context obtain enough emphasis in an end-to-end trained 3D scene understanding network. To guide 3D feature learning toward important geometric attributes and scene context, we explore the help of textual scene descriptions. Given some free-form descriptions paired with 3D scenes, we extract the knowledge regarding the object relationships and object attributes. We then inject the knowledge to 3D feature learning through three classification-based auxiliary tasks. This language-assisted training can be combined with modern object detection and instance segmentation methods to promote 3D semantic scene understanding, especially in a label-deficient regime. Moreover, the 3D feature learned with language assistance is better aligned with the language features, which can benefit various 3D-language multimodal tasks. Experiments on several benchmarks of 3D-only and 3D-language tasks demonstrate the effectiveness of our language-assisted 3D feature learning. Code is available at https://github.com/Asterisci/Language-Assisted-3D
Soft Robotic Textiles for Adaptive Personal Thermal Management
Abstract Thermal protective textiles are crucial for safeguarding individuals, particularly firefighters and steelworkers, against extreme heat, and for preventing burn injuries. However, traditional firefighting gear suffers from statically fixed thermal insulation properties, potentially resulting in overheating and discomfort in moderate conditions, and insufficient protection in extreme fire events. Herein, an innovative soft robotic textile is developed for dynamically adaptive thermal management, providing superior personal protection and thermal comfort across a spectrum of environmental temperatures. This unique textile features a thermoplastic polyurethane (TPU)âsealed actuation system, embedded with a low boiling point fluid for reversible phase transition, resembling an endoskeleton that triggers an expansion within the textile matrix for enhanced air gap and thermal insulation. The thermal resistance improves automatically from 0.23 to 0.48 Km2 Wâ1 by selfâactuating under intense heat, exceeding conventional textiles by maintaining over 10 °C cooler temperatures. Additionally, the knitted substrate incorporated into the soft actuators can substantially mitigate convective heat transfer, as evidenced by the thermal resistance tests and the temperature mapping derived from numerical simulations. Moreover, it boasts significantly increased moisture permeability. The thermoadaptation and breathability of this durable allâfabric system signify considerable progress in the development of protective clothing with high comfort for dynamic and extreme temperature conditions
Microbiotaâmuscle/immune interactions in rhesus macaque under simulated microgravity revealed by integrated multiâomics analysis
Abstract Background Longâterm exposure to microgravity during spaceflight has adverse effects on human health including muscle atrophy, impaired immune function, and alterations in gut microbiome profile. Gut microorganisms influence a wide range of host biological processes, but their interactions with skeletal muscle and the immune system under microgravity have yet to be elucidated. Methods Rhesus macaques (Macaca mulatta) were subjected to â6° headâdown tilted bed rest (HDBR) for 6 weeks. Faecal samples, skeletal muscle tissue, and peripheral blood mononuclear cells (PBMCs) were collected for metagenomic, metabolomic, and transcriptomic analyses, respectively, and further integrated for a multiâomics analysis. Results Headâdown tilted bed rest significantly altered taxon abundance (P 1.2, variable importance in projection >1) in atrophied muscles, including some crucial metabolites (such as lâalanine and lâcarnitine) and hub metabolites (such as pyridoxamine and epinephrine) involved in energy metabolism. Transcriptomic analysis of PBMCs revealed genes related to leucocyte activation, differentiation, and interleukinâ2 production that were differentially expressed as a result of HDBR exposure (fold change >2 and P < 0.05). By integrating multiâomics analysis, we identified three bacterial genera (Klebsiella, Kluyvera, and Bifidobacterium) that were closely associated with immune dysfunction and five (including Oligella, Sporosarcina, Citrobacter, Weissella, and Myroides) that were associated with abnormal metabolism of amino acids in atrophied muscles induced by HDBR. The reduced abundance of butyrateâproducing colon bacteria Eubacterium, Roseburia, and their crossâfeeding bacteria Bifidobacteria may contribute to the impaired immune function and muscle atrophy caused by HDBR. Conclusions This is the first report of the HDBRâassociated changes in gut microbiota composition, metabolomics of skeletal muscle, and transcripts of PBMCs in a nonâhuman primate. The underlying microbiotaâmuscle and microbiotaâimmune interactions during simulated microgravity imply that modulation of gut microbiota may represent a novel strategy for enhancing the health and safety of crew members during longâterm space expeditions