This paper studies the problem of adaptive fuzzy control based on command filtering for a class of nonlinear systems characterized by an input dead zone, input saturation, and unknown control ...direction. First, this paper proposes a novel equivalent transformation technique that simplifies the design complexity of multiple input constraints by converting the input dead zone and saturation nonlinearities into a unified functional form. Subsequently, a fuzzy logic system is utilized to handle the unknown nonlinear functions, and the command-filtering method is employed to address the issue of complexity explosion, while the Nussbaum function is utilized to resolve the challenge of an unknown control direction. Based on Lyapunov stability, it is proven that the tracking error converges to a small neighborhood around the origin, and all closed-loop signals are bounded. Finally, a numerical simulation result and an actual simulation result of a pendulum are presented to verify the feasibility and effectiveness of the proposed control strategy.
With the advancement of embedded systems, their application across diverse sectors has notably expanded. This paper delineates the fundamental architecture of embedded systems and separately ...engineers the hardware and software components for an energy-efficient embedded system tailored for electrical engineering automation. The focus is placed on the energy-saving control module of the embedded system, which incorporates fuzzy logic with a PID control algorithm to produce definitive signal outputs. Building upon this foundation, the performance of this enhanced algorithm was evaluated and subsequently implemented in the tunnel lighting electrical engineering project. The findings reveal that the embedded system-controlled lighting setup can adjust the tunnel entrance and mouth lighting based on external luminance levels, maintaining daily energy consumption at approximately 550 kWh with an energy savings rate reaching as high as 51% per day. This study affirms the substantial potential of embedded systems in advancing energy-efficient solutions within electrical engineering automation.
As the scale of the electrical system becomes more and more large and the structure becomes more and more complex, the performance of the electrical automation device is therefore required to be ...higher. This paper studies the electrical system automation device, and from the perspective of universality, designs and establishes the hardware platform of the electrical system automation device composed of six plug-ins, such as human-machine interface, auxiliary switch input, AC input, communication, power supply, and central processor. On this basis, μC/OS-II is adopted as the embedded real-time operating system of this paper to develop and design the software of the electrical system automation device. Then, the principle of the protection device for embedded system electrical automation is analyzed, and a microcomputer line protection device based on the full-circle Fuchs algorithm is proposed. The empirical analysis of the embedded system electrical automation device shows that the maximum system task response time is 145 μs and the minimum is 10 μs, which are all no more than 1 ms. When testing including the single board state, the keyboard, the alphabetical mode, the basic function, and the single board line module sending and receiving, the pass rate of all the testing items is more than 99%, which verifies that this paper is based on the embedded real-time operating system of the feasibility and effectiveness of the electrical automation device.
Tissue-specific gene expression requires coordinated control of gene-proximal and -distal cis-regulatory elements (CREs), yet functional analysis of gene-distal CREs such as enhancers remains ...challenging. Here we describe CRISPR/dCas9-based enhancer-targeting epigenetic editing systems, enCRISPRa and enCRISPRi, for efficient analysis of enhancer function in situ and in vivo. Using dual effectors capable of re-writing enhancer-associated chromatin modifications, we show that enCRISPRa and enCRISPRi modulate gene transcription by remodeling local epigenetic landscapes at sgRNA-targeted enhancers and associated genes. Comparing with existing methods, the improved systems display more robust perturbations of enhancer activity and gene transcription with minimal off-targets. Allele-specific targeting of enCRISPRa to oncogenic TAL1 super-enhancer modulates TAL1 expression and cancer progression in xenotransplants. Single or multi-loci perturbations of lineage-specific enhancers using an enCRISPRi knock-in mouse establish in vivo evidence for lineage-restricted essentiality of developmental enhancers during hematopoiesis. Hence, enhancer-targeting CRISPR epigenetic editing provides opportunities for interrogating enhancer function in native biological contexts.
Nanomaterials are widely used in daily life owing to their superior characteristics. The release and transport of nanoparticles (NPs) in the environment is inevitable during their entire life cycle, ...posing a risk to the aquatic environment. Thus, considerable attention has been focused on the fate and behavior of NPs in porous media, as well as the co-transport of NPs with other pollutants. In this review, current knowledge about the retention and transport behavior of NPs in porous media is summarized. NP transport in porous media is dominated by various internal and external factors, including the characteristics of NPs, porous media, and water flow. Generally, NPs with high density, small particle size, and surface coating are easily transported in porous media with the characteristics of large size, smooth surface, and low water saturation. Meanwhile, high pH and velocity, low temperature, and natural organic matter-containing fluids are also conducive to NP transport. Aggregation, adsorption, straining, and blocking are the primary mechanisms by which NPs affect the transport of co-existing pollutants in porous media. Current research on NP transport has been performed predominantly using modal porous media (e.g., sand and glass beads); however, there is a large gap between simulated and natural porous media. Further studies should focus on the transport, fate, and interaction of NPs and coexistent pollutants in natural porous media, as well as the coupling mechanisms under actual environmental conditions.
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•The transport of NPs is affected by the properties of NPs, porous media and fluid.•Aggregation, adsorption, straining and blocking are the main mechanisms involved.•NPs can change the diffusion of co-existing pollutants and co-transport with them.•Interaction of NPs and pollutants in natural media requires further investigation.
This work first demonstrates the improved electromagnetic interference (EMI) shielding performance of monolayer graphene on highly transparent metal-meshes of random pattern. Metal-meshes are ...fabricated on quartz substrate by lift-off based on self-cracking template and CVD graphene is directly transferred onto thin metal-meshes to construct the hierarchical graphene/metal-mesh film, by which considerable improvements both in microwave reflection and absorption can be realized in thin metal-meshes. The shielding effectiveness (SE) of the hierarchical film even exceeds the summation of those of the monolayer graphene and the metal-mesh film. Detailed analyses reveal that absorption dominates the improvement in SE for a graphene/50 nm Ag-mesh film, with a three-fold absorption coefficient as well as a slightly increased reflectivity compared to the Ag-mesh itself. The as-prepared hierarchical film primely inherits the excellent optical transmission properties from random-pattern metal-meshes with high transmittance in visual-IR spectrum, low haze and faint diffraction. Moreover, the chemical stability of metal-meshes is highly improved with the protection of graphene. We anticipate that the hierarchical graphene/metal-mesh film can be a promising material to play a great role in realization of high-performance EMI shielding in emerging optoelectronic devices such as touch panels, displays, airborne optoelectronic pods, and aviation camcorders.
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Abstract
Carbon neutrality initiative has stimulated the development of the sustainable methodologies for hydrogen generation and safe storage. Aqueous-phase reforming methanol and H
2
O (APRM) has ...attracted the particular interests for their high gravimetric density and easy availability. Thus, to efficiently release hydrogen and significantly suppress CO generation at low temperatures without any additives is the sustainable pursuit of APRM. Herein, we demonstrate that the dual-active sites of Pt single-atoms and frustrated Lewis pairs (FLPs) on porous nanorods of CeO
2
enable the efficient additive-free H
2
generation with a low CO (0.027%) through APRM at 120 °C. Mechanism investigations illustrate that the Pt single-atoms and Lewis acidic sites cooperatively promote the activation of methanol. With the help of a spontaneous water dissociation on FLPs, Pt single-atoms exhibit a significantly improved reforming of *CO to promote H
2
production and suppress CO generation. This finding provides a promising path towards the flexible hydrogen utilizations.
The 26th Conference of the Parties (COP26) to the United Nations Framework Convention on Climate Change (UNFCCC) was held in Glasgow a year later than scheduled, with expected outcomes achieved under ...a post-pandemic background. Based on the Issue-Actor-Mechanism Framework, this paper systematically evaluates the outcomes achieved at COP26 and analyzes the tendency of post-COP26 climate negotiations. Overall, with the concerted efforts of all parties, COP26 has achieved a balanced and inclusive package of outcomes and concluded six years of negotiations on the Paris Rulebook. It is fair to say that COP26 is another milestone in climate governance following the implementation of the Paris Agreement. Meanwhile, the Glasgow Climate Pact has cemented the consensus on a global commitment to accelerating climate action over the next decade and reached a breakthrough consensus on reducing coal, controlling methane, and halting deforestation. In the post-COP26 era, we still need to take concrete actions to implement the outcomes of the Paris Agreement and the Glasgow Climate Pact, innovate ways to speed up CO
2
emissions reduction, and continue to strive for breakthroughs in important issues such as finance, technology, adaptation, and collaboration. In addition to avoiding the escalation of international conflicts, we need to collectively and properly handle the relationship between energy security, carbon reduction, and development and facilitate the efforts of countries to achieve their Sustainable Development Goals (SDGs), including climate-related goals. China will continue to maintain the existing multilateral mechanisms and processes for climate governance, unremittingly take concrete actions to address climate change, promote a domestic comprehensive green transition and global cooperation on carbon neutrality, and contribute constructively to global climate governance.
Polysaccharides have been widely used as biomaterials and drugs after oral administration due to their suitable physicochemical properties, good bioactivities and low toxicities. However, studies on ...their pharmacokinetics and absorption mechanism after oral administration are significantly restricted by the lack of polysaccharide detection methods. With the advancement of polysaccharide detection technologies such as immunoassays, fluorescent and isotopic labelling, the oral pharmacokinetics of polysaccharides have gradually been revealed. Here, paracellular pathway, transcellular pathways and M cell-mediated transport were analysed as mechanisms for oral absorption. The potential factors affecting the oral absorption of polysaccharides, including their charge, molecular weight, spatial structure and dose, as well as the species and physiological state of organisms, were analysed. Based on the absorption mechanism and influencing factors, we look forward to further investigating possible strategies for improving the oral absorption of polysaccharides.
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Cu-doped Li4Ti5O12/graphene composite (Cu-LTO@FG) was successfully prepared using a facile hydrothermal process coupled with a freeze-drying process. The Cu-doping can produce a large number of ...structure defects including oxygen vacancies and stacking faults in Li4Ti5O12 nanosheets, greatly improving the intrinsic electrical conductivity. Meanwhile, the graphene network ensures high-efficiency electron conduction and Li+ diffusion not only around the Li4Ti5O12 nanosheets but also through the overall electrode. Thus the as-fabricated composite possesses a continuous conductive path to accelerate the motion of electron and Li+ inside and outside the Li4Ti5O12 nanosheets. The Cu-LTO@FG exhibits superb specific capacity of 177.3 mA h g−1 after 100 cycles at 1 C (1 C = 175 mA h g−1), excellent rate capability up to 20 C with a specific capacity of 160.6 mA h g−1, and outstanding cycling stability as anode material for lithium-ion battery. The extraordinary electrochemical performance is related to the improved electronic conductivity and pseudocapacitive effect, which lead to faster surface charge-transfer and excess lithium-ion storage. In addition, benefiting from the synergistic effect of structure defects and graphene network, the Cu-LTO@FG stores more lithium-ion and alleviates agglomeration of the Li4Ti5O12 nanosheets. Thus, the combined strategy with the Cu-doping and graphene network shows its great potential in improving the performance of anode material for high-rate LIBs.
•Cu-doped LTO/graphene composite was prepared by hydrothermal and freeze-drying.•The continuous conductive network was built up by Cu-doping and graphene wrapping.•The composite shows high capacity, rate capability and cycling stability.
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