Platinum-based materials show excellent electrocatalytic performance and have good potential for use in fuel cells. However, the high cost and scarce reserves have restricted their wide application. ...Therefore, it is a challenging task to reduce the amount of Pt as well as ensure good catalytic performance. Herein, anchoring of Pt single atoms (0.21 wt‰) with ultra-low content on g-C3N4 nanosheets (Pt0.21/CN) has been successfully achieved. The obtained Pt0.21/CN catalyst shows excellent two-electron oxygen reduction (2e− ORR) capability for hydrogen peroxide (H2O2). Compared with CN, its H2O2 selectivity increased from 80% to 98% in 0.1 M KOH, surpassing those in most of the reported studies. Besides, the H2O2 production rate of Pt0.21/CN is 767 mmol gcat−1 h−1, which is 11.1 times that of CN. This work may pave the way toward the development of an effective method for the design of noble-metal electrocatalysts with low metal loading and high catalytic activity.
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•A class of stretchable microstrip antennas is designed with serpentine mesh layouts using a set of non-dimensional parameters.•Non-dimensional parameters can tune the coupled ...mechanical-electromagnetic properties of stretchable microstrip antennas at various tensile strain levels.•The advanced laser micromachining technology can efficiently and precisely fabricate stretchable microstrip antennas from conventional metals at a low cost.•The demonstrated toolkit on coupled mechanics-electromagnetics can also be applied to the other stretchable microwave devices.
With the rapid development of flexible/stretchable electronics, wireless technology for wearable systems starts to gain momentum. Here, a class of stretchable microstrip antennas composed of serpentine mesh layouts in both the patch and ground plane is designed. The study of the representative stretchable microstrip antenna reveals the effects of the geometric parameters on its electromagnetic properties. Although the non-dimensional parameters have been shown to uniquely determine the mechanical properties of the serpentine mesh structure, their influence on the coupled mechanical-electromagnetic properties is different in the stretchable antenna. This study systematically reveals the effects of the non-dimensional parameters at various tensile strain levels from the coupled mechanics-electromagnetics simulations, with experimental validations. The mechanical stretchability of the serpentine mesh structure increases as the arc angle increases or the normalized width (i.e., the ratio of the width to radius) decreases. The normalized width together with the change in radius and width provides an effective means to tune the initial resonance frequency, impedance matching, and radiation pattern of the stretchable antenna without altering the strain sensitivity. Additionally, the advanced laser micromachining technology for the manufacturing of the stretchable microstrip antenna can also be explored to the other stretchable microwave devices.
Al nanoparticles (ANPs) have high reactivity and can improve the system’s combustion performance. However, ANPs are susceptible to inactivation by external oxidants. Here, we use ethanol and ether ...molecules to coat ANPs and then compare and discuss the combustion process between coated ANPs and bare ANPs. Our results show that the ethanol/ether coating can adsorb more H2O molecules and increase the active Al atom number and the Al core area in the ignition stage. The combustion phase can be divided into four stages according to the rate of the combustion temperature. The ethanol/ether coating can enable ANPs to deliver a better combustion performance, reducing the ignition delay time of particles, greatly increasing the combustion temperature, and making the whole system enter the gas phase combustion stage. These will enable the ethanol/ether–ANPs systems to release more energy and improve the combustion efficiency of the system.
A new platform for N-glycoprotein analysis from serum that combines matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) workflows with antibody slide arrays is ...described. Antibody panel based (APB) N-glycan imaging allows for the specific capture of N-glycoproteins by antibodies on glass slides and N-glycan analysis in a protein-specific and multiplexed manner. Development of this technique has focused on characterizing two abundant and well-studied human serum glycoproteins, alpha-1-antitrypsin and immunoglobulin G. Using purified standard solutions and 1 μL samples of human serum, both glycoproteins can be immunocaptured and followed by enzymatic release of N-glycans. N-Glycans are detected with a MALDI FT-ICR mass spectrometer in a concentration-dependent manner while maintaining specificity of capture. Importantly, the N-glycans detected via slide-based antibody capture were identical to that of direct analysis of the spotted standards. As a proof of concept, this workflow was applied to patient serum samples from individuals with liver cirrhosis to accurately detect a characteristic increase in an IgG N-glycan. This novel approach to protein-specific N-glycan analysis from an antibody panel can be further expanded to include any glycoprotein for which a validated antibody exists. Additionally, this platform can be adapted for analysis of any biofluid or biological sample that can be analyzed by antibody arrays.
Although cerium oxide nanoparticles are attracting much attention in the biomedical field due to their unique physicochemical and biological functions, the cerium oxide nanoparticles greatly suffer ...from several unmet physicochemical challenges, including loss of enzymatic activity during the storage, non-specific cellular uptake, off-target toxicities, etc. Herein, in order to improve the targeting property of cerium oxide nanoparticles, we first modified cerium oxide nanoparticles (CeO2) with polyacrylic acid (PAA) and then conjugated with an endothelium-targeting peptide glycine-arginine-aspartic acid (cRGD) to construct CeO2@PAA@RGD. The physiochemical characterization results showed that the surface modifications did not impact the intrinsic enzymatic properties of CeO2, including catalase-like (CAT) and superoxide dismutase-like (SOD) activities. Moreover, the cellular assay data showed that CeO2@PAA@RGD exhibited a good biocompatibility and a higher cellular uptake due to the presence of RGD targeting peptide on its surface. CeO2@PAA@RGD effectively scavenged reactive oxygen species (ROS) to protect cells from oxidative-stress-induced damage. Additionally, it was found that the CeO2@PAA@RGD converted the phenotype of macrophages from proinflammatory (M1) to anti-inflammatory (M2) phenotype, inhibiting the occurrence of inflammation. Furthermore, the CeO2@PAA@RGD also promoted endothelial cell-mediated migration and angiogenesis. Collectively, our results successfully demonstrate the promising application of CeO2@PAA@RGD in the future biomedical field.
The use of slag-based alkali-activated concrete (AAC) could effectively address the issues of resource extraction and carbon emissions caused by traditional Portland cement. In this study, the ...effects of the fly ash content, water–binder ratio, and alkali activation modulus on the early mechanical properties of AAC were investigated. A total of 105 cube specimens (35 sets) were designed and subjected to compressive strength tests, scanning electron microscope tests, and x-ray diffraction composition analysis. The results indicated that excellent early strength was observed in AAC, with a compressive strength reaching ∼90% of the 28th day strength before 14 days. An increase in the fly ash content and a decrease in the water–binder ratio significantly improved the compressive strength within the same age period. The impact of a lower alkaline activation modulus on strength was found to be insignificant. Based on the experimental results, a calculation method and a constitutive model for early strength were proposed, and the theoretical values exhibited a high level of agreement with the measured values.
Global warming significantly affects plateau glaciers and surface runoff, and fish are bound to be severely affected. Additionally, an increasing number of human activities (e.g., free captive ...animals, aquaculture) have led to vulnerable plateau ecosystems being affected by invasive species. To address the above issues, we collected the currently published fish distribution data, and for the first time constructed a richness and fluvial system distribution map of the Yarlung Zangbo River fish (4 orders, 10 families, and 61 species). Based on fish richness and the fluvial system, the native fish in the Yarlung Zangbo River Basin were divided into three clusters, and the non-native fish were divided into six clusters by using Ward’s minimum variance clustering and non-metric multidimensional scaling (NMDS). Environmental factors related to native or non-native fish richness were selected by the random forest model from 21 environmental factors. Then, the relationship between fish richness and environmental factors was explained by the generalized linear model (GLM). Our results showed that the native fish distribution pattern was different from the non-native fish distribution, but their high richness areas were overlapped. Furthermore, native fish richness responds differently than non-native fish richness to environmental factors. The results provided eco-solutions for the conservation and management of fish biodiversity and natural resources in the Yarlung Zangbo River.
An optimization method based on the sensitivity of global and local geometric parameters is proposed to improve the cooling efficiency of E3 engine nozzle guide vane. For 29 geometric parameters that ...affect the vane maximum temperature in the cooling design, the sensitivity ranking of them is firstly obtained by the DOE method. Then the most influential parameters including the diameter or location of the film cooling hole are selected as the optimization variables to decrease the maximum surface temperature of the nozzle guide vane. On this basis, to further reduce the local temperature downstream the pressure side, a new duck-paw type film cooling hole is applied. The duck-paw type film cooling hole was produced with the adjoint method through identifying the sensitivity of the geometric boundary parameters of the film cooling holes. Compared to the cylindrical holes, the duck-paw shaped film cooling hole can greatly improve the cooling efficiency under the same conditions. The duck-paw type film cooling holes are applied to the last two rows of film cooling holes located on the pressure side of nozzle guide vane. Three-dimensional conjugate flow and heat transfer analysis results show that the maximum temperature of the optimized cooling structure vane is reduced by 39K, and the average temperature decreases by nearly 20K.
This paper presents the analysis and design of a miniaturized polarization insensitive metamaterial absorber (MMA) for suppression of the electromagnetic interference (EMI) at microwave frequency ...range. The proposed MMA consists of a periodic array of double split ring structures printed on an FR4 substrate with a thickness of 0.07 λ 0 . The simulated results derived from CST indicate that the absorption ratio of the MMA is over 90% with a wide frequency range from 8.3 GHz to 11.3 GHz for a normal incident electromagnetic (EM) wave. To understand the EM wave absorption mechanism, an equivalent circuit model of the MMA unit cell is constructed to investigate the absorbing characteristics, and the electric field and surface current distributions are analyzed at absorption peaks.. Both equivalent circuit model (ECM) and measured results show good agreement. What's more, the measurement data shows that the radiated electric field of the patch antenna at 1 meter is significantly reduced at 10 GHz while loading with the MMA. A maximum suppression of 18 dBμν/m is achieved at 10 GHz. As the proposed absorber possesses good ability on electromagnetic radiation absorption, it could be well applied on printed circuit board (PCB) level EMI suppression.
This paper identifies 20 critical success factors (CSFs) of innovation in China's construction projects through literature review, a case study and expert interviews. Integrated Structural Modeling ...(ISM) and MICMAC (Impact Matrix Cross-reference Multiplication Applied to a Classification) analysis were used to hierarchically structure CSFs as well as to analyze their inter-relationships. The dependence and driver power of each factor were also analyzed. By doing this, this paper presents structural clarity and establishes a hierarchical order for prioritization for the decision-making. The findings show that most of the CSFs (19 out of 20) have strong inter-relationships. According to the law of vital few and trivial many, 80% of effects come from 20% of the causes for many events. This paper suggests that intensive effort should focus on the root source of CSFs: owner's involvement and leadership, top management commitment, and strategic importance of the innovation project. Besides, external support, which is beyond the innovation project network, plays an important role in the success of innovation in China's construction projects.
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