31 research outputs found
Nitrogen Photofixation over IIIâ Nitride Nanowires Assisted by Ruthenium Clusters of Low Atomicity
In many heterogeneous catalysts, the interaction of supported metal species with a matrix can alter the electronic and morphological properties of the metal and manipulate its catalytic properties. IIIâ nitride semiconductors have a unique ability to stabilize ultraâ small ruthenium (Ru) clusters (ca. 0.8â nm) at a high loading density up to 5â wtâ %. nâ Type IIIâ nitride nanowires decorated with Ru subâ nanoclusters offer controlled surface charge properties and exhibit superior UVâ and visibleâ light photocatalytic activity for ammonia synthesis at ambient temperature. A metal/semiconductor interfacial Schottky junction with a 0.94â eV barrier height can greatly facilitate photogenerated electron transfer from IIIâ nitrides to Ru, rendering Ru an electron sink that promotes Nâ ¡N bond cleavage, and thereby achieving lowâ temperature ammonia synthesis.IIIâ Nitridâ Halbleiter stabilisieren Rutheniumcluster mit Beladungsdichten bis 5â Gew.â %. Der Schottkyâ à bergang an der Grenzfläche zwischen Metall und Halbleiter begünstigt den Transfer von Photoelektronen aus den IIIâ Nitriden auf das Ruthenium, das dadurch die Spaltung der Nâ ¡Nâ Bindung in einer Niedertemperatursynthese von Ammoniak bewirken kann.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137688/1/ange201703301_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137688/2/ange201703301-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137688/3/ange201703301.pd
Position-Enhanced Visual Instruction Tuning for Multimodal Large Language Models
Recently, Multimodal Large Language Models (MLLMs) that enable Large Language
Models (LLMs) to interpret images through visual instruction tuning have
achieved significant success. However, existing visual instruction tuning
methods only utilize image-language instruction data to align the language and
image modalities, lacking a more fine-grained cross-modal alignment. In this
paper, we propose Position-enhanced Visual Instruction Tuning (PVIT), which
extends the functionality of MLLMs by integrating an additional region-level
vision encoder. This integration promotes a more detailed comprehension of
images for the MLLM. In addition, to efficiently achieve a fine-grained
alignment between the vision modules and the LLM, we design multiple data
generation strategies to construct an image-region-language instruction
dataset. Finally, we present both quantitative experiments and qualitative
analysis that demonstrate the superiority of the proposed model. Code and data
will be released at https://github.com/PVIT-official/PVIT
Nitrogen Photofixation over III-Nitride Nanowires Assisted by Ruthenium Clusters of Low Atomicity
In many heterogeneous catalysts, the interaction of supported metal species with a matrix can alter the electronic and morphological properties of the metal and manipulate its catalytic properties. III-nitride semiconductors have a unique ability to stabilize ultra-small ruthenium (Ru) clusters (ca. 0.8 nm) at a high loading density up to 5 wt %. n-Type III-nitride nanowires decorated with Ru sub-nanoclusters offer controlled surface charge properties and exhibit superior UV- and visible-light photocatalytic activity for ammonia synthesis at ambient temperature. A metal/semiconductor interfacial Schottky junction with a 0.94 eV barrier height can greatly facilitate photogenerated electron transfer from III-nitrides to Ru, rendering Ru an electron sink that promotes N≡N bond cleavage, and thereby achieving low-temperature ammonia synthesis
The Boom in 3D-Printed Sensor Technology
Future sensing applications will include high-performance features, such as toxin detection, real-time monitoring of physiological events, advanced diagnostics, and connected feedback. However, such multi-functional sensors require advancements in sensitivity, specificity, and throughput with the simultaneous delivery of multiple detection in a short time. Recent advances in 3D printing and electronics have brought us closer to sensors with multiplex advantages, and additive manufacturing approaches offer a new scope for sensor fabrication. To this end, we review the recent advances in 3D-printed cutting-edge sensors. These achievements demonstrate the successful application of 3D-printing technology in sensor fabrication, and the selected studies deeply explore the potential for creating sensors with higher performance. Further development of multi-process 3D printing is expected to expand future sensor utility and availability
Simple and Efficient System for Combined Solar Energy Harvesting and Reversible Hydrogen Storage
Solar
energy harvesting and hydrogen economy are the two most important
green energy endeavors for the future. However, a critical hurdle
to the latter is how to safely and densely store and transfer hydrogen.
Herein, we developed a reversible hydrogen storage system based on
low-cost liquid organic cyclic hydrocarbons at room temperature and
atmospheric pressure. A facile switch of hydrogen addition (>97%
conversion)
and release (>99% conversion) with superior capacity of 7.1 H<sub>2</sub> wt % can be quickly achieved over a rationally optimized
platinum catalyst with high electron density, simply regulated by
dark/light conditions. Furthermore, the photodriven dehydrogenation
of cyclic alkanes gave an excellent apparent quantum efficiency of
6.0% under visible light illumination (420–600 nm) without
any other energy input, which provides an alternative route to artificial
photosynthesis for directly harvesting and storing solar energy in
the form of chemical fuel
Photoinduced Conversion of Methane into Benzene over GaN Nanowires
As a class of key building blocks
in the chemical industry, aromatic
compounds are mainly derived from the catalytic reforming of petroleum-based
long chain hydrocarbons. The dehydroaromatization of methane can also
be achieved by using zeolitic catalysts under relatively high temperature.
Herein we demonstrate that Si-doped GaN nanowires (NWs) with a 97%
rationally constructed <i>m</i>-plane can directly convert
methane into benzene and molecular hydrogen under ultraviolet (UV)
illumination at rt. Mechanistic studies suggest that the exposed <i>m</i>-plane of GaN exhibited particularly high activity toward
methane C–H bond activation and the quantum efficiency increased
linearly as a function of light intensity. The incorporation of a
Si-donor or Mg-acceptor dopants into GaN also has a large influence
on the photocatalytic performance
Design, Synthesis, and Anti-Inflammatory Activities of 12-Dehydropyxinol Derivatives
Pyxinol skeleton is a promising framework of anti-inflammatory agents formed in the human liver from 20S-protopanaxadiol, the main active aglycone of ginsenosides. In the present study, a new series of amino acid-containing derivatives were produced from 12-dehydropyxinol, a pyxinol oxidation metabolite, and its anti-inflammatory activity was assessed using an NO inhibition assay. Interestingly, the dehydrogenation at C-12 of pyxinol derivatives improved their potency greatly. Furthermore, half of the derivatives exhibited better NO inhibitory activity than hydrocortisone sodium succinate, a glucocorticoid drug. The structure–activity relationship analysis indicated that the kinds of amino acid residues and their hydrophilicity influenced the activity to a great extent, as did R/S stereochemistry at C-24. Of the various derivatives, 5c with an N-Boc-protected phenylalanine residue showed the highest NO inhibitory activity and relatively low cytotoxicity. Moreover, derivative 5c could dose-dependently suppress iNOS, IL-1β, and TNF-α via the MAPK and NF-κB pathways, but not the GR pathway. Overall, pyxinol derivatives hold potential for application as anti-inflammatory agents
An internal electrode strategy for enhancing the stability and durability of triboelectric nanogenerator
In this study, an internal electrode triboelectric nanogenerator (IE-TENG) design is proposed to enhance the stability, durability, and long-term performance of TENGs. By embedding a mesh-structured metal electrode in the friction layer, the IE-TENG becomes more flexible, lightweight, and robust than the traditional external electrode TENG (EE-TENG). When using copper mesh internal electrodes with higher grid density, the greater output can be achieved by comparing a series of polydimethylsiloxane(PDMS)-based IE-TENG. An equivalent output was obtained when using 60 copper mesh compared to EE-TENG, and the trend maintains for tribonegative low-density polyethylene (LDPE) and tribopositive polyamide (PA) polymers, which verifies the usability of the approach and the effective induction area of the internal electrode. The internal electrode design significantly enhanced the tolerance of the device to harsh environments and guaranteed excellent output stability. In addition, the IE-TENGs possess superior resistance to external interference and had about one time shorter saturation time for surface charges. As a demonstration, the IE-TENG can be used for collecting motion-sensing signals and detecting various sports activities. This study provides a novel strategy for the designing and customizing of highly integrated TENGs with enhanced durability for practical long-term applications