This paper examines a class of fractional p-Kirchhoff systems driven by a nonlocal integro-differential operator with singular nonlinearity. By making use of Nehari manifold techniques, the existence ...of two nontrivial solutions is established. Our results extend those in Xiang et al. Nonlinearity 29(2016), 3186–3205 for the corresponding subcritical case.
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•UiO-66-NH2 can effectively remove norfloxacin in water.•UiO-66-NH2 can remove norfloxacin well in the neutral pH range.•The NH2 and ZrO bonds play important role for norfloxacin ...removal.•Various adsorption mechanisms for norfloxacin removal are explored.
Antibiotics abuse has been a significant threat to the environment and human health. In this study, we successfully synthesized highly stable amino-functionalized Zr-based metal–organic frameworks (UiO-66-NH2) and studied the adsorption behaviors of norfloxacin (NOR) in water. The adsorption capacities of UiO-66-NH2 reached a maximum of 222.5 mg/g for NOR, which were considerably higher than that of most reported adsorbents. Moreover, the equilibrium time (6 h) was less than that of several previously reported adsorbents. Ionic-strength-influenced experiments showed that NaCl and CaCl2 aqueous solutions could improve the removal efficiency of NOR. The presence of humic acid could barely affect the adsorption amount. At a concentration of 10 mg/L, the highest partition coefficient of 20.9 mg/g/µM was obtained, and the removal rate of NOR was as high as 91.6%, implying that UiO-66-NH2 offered considerable adsorption performance at a low concentration of NOR. In addition, UiO-66-NH2 exhibited good regeneration efficiency, thus offering the possibility to remove norfloxacin from sewage. Finally, several credible adsorption mechanisms were proposed. The results will aid us to comprehend the surface interaction between organic micropollutants and UiO-66-NH2 and prefigure the potential of UiO-66-NH2 as a novel adsorbent for the removal of NOR.
Cardiovascular diseases (CVDs) have become a serious threat to human life and health. Though many drugs acting via different mechanism of action are available in the market as conventional ...formulations for the treatment of CVDs, they are still far from satisfactory due to poor water solubility, low biological efficacy, non-targeting, and drug resistance. Nano-drug delivery systems (NDDSs) provide a new drug delivery method for the treatment of CVDs with the development of nanotechnology, demonstrating great advantages in solving the above problems. Nevertheless, there are some problems about NDDSs need to be addressed, such as cytotoxicity. In this review, the types and targeting strategies of NDDSs were summarized, and the new research progress in the diagnosis and therapy of CVDs in recent years was reviewed. Future prospective for nano-carriers in drug delivery for CVDs includes gene therapy, in order to provide more ideas for the improvement of cardiovascular drugs. In addition, its safety was also discussed in the review.
Building energy saving is of great practical interest due to the increasing energy consumption in buildings. The optimal control of the heating, ventilation, and air-conditioning (HVAC) systems leads ...to great energy saving potential. However, this problem is challenging due to the exponentially increasing state space and policy space. In this brief, we consider this important problem and make the following major contributions. First, we formulate the multiroom HVAC control problem as an event-based optimization, where decisions are made only when certain events occur. The size of the event space is significantly smaller than that of the state space. Second, to further simplify the calculation process, we develop an approximate solution method which focuses on local-event-based policies. These policies control the terminal devices in a room using solely the information in that room. Third, we demonstrate the performance of this method through two sets of numerical examples. In the small-scale two-room example, it is shown that our method can achieve a near-optimal solution. In the large-scale example, it is shown that the local-event-based approach can achieve a policy which is better than the threshold-based control method, hysteresis control method, and predictive control method.
•Southwestern monsoon induced phytoplankton bloom in the southwest BoB.•Bivariate wavelet coherence identifies wind as the best factor to explain Chla change.•Multiple wavelet coherence effectively ...identifies WSP-SST to explain Chla change.•Weakening southwest monsoon and warm eddy led to the lowest Chla in 2015 El Niño.
The Bay of Bengal (BoB) has distinctive hydrological characteristics, and various physical mechanisms strongly influence the growth of phytoplankton in this region. In this work, we investigated the monthly and interannual variations of phytoplankton biomass (PB) in the southwestern (SW) BoB (78–88°E, 0–15°N) utilizing satellite data from 2003 to 2018. Bivariate wavelet coherence (BWC) and multiple wavelet coherence (MWC) analyses were conducted to assess the temporal fluctuations in various physical oceanographic parameters. The findings revealed that wind speed (WSP) and sea surface temperature (SST) were the main drivers for the monthly variations of chlorophyll-a (Chl-a). The southwest monsoon promoted the formation of upwelling by offshore Ekman transport via the southwest monsoon current (SMC) and the upward Ekman pumping induced by the strong positive wind stress curl, which brought nutrient-rich, cold waters from the subsurface to the surface, stimulating phytoplankton growth. The BWC analysis results identified WSP as the most effective individual factor accounting for the interannual fluctuations in Chl-a concentrations. The MWC analysis results unraveled that the combinations of WSP–SST, WSP–Niño 3.4, WSP–EPV, and WSP–DMI exhibited the strongest relationships with the changes in Chl-a in the SW BoB. The PB in 2015 demonstrated abnormally low values. The El Niño event in 2015 substantially weakened the southwest monsoon and current, possibly weakening the Ekman transport on the southern coast of Sri Lanka and India. Moreover, an abnormally intensified anticyclonic eddy occurred in this region. These processes disrupted the vertical exchange of nutrients, obstructing the vertical transport of nutrient-enriched subsurface waters and leading to abnormally decreased levels of Chl-a in 2015.
With a strong ability in tailoring molecular structure, nanoscale morphology, and nanodomains, the ferromagnetic metal-organic framework (MOF, M = transition metal) has been considered an ...advantageous candidate material for dielectric nanocomposites. Herein, a pristine content-controlled Ag nanoparticle driving Ni metal-organic framework (Ag-NiMOF) ultra-thin 2D ferroelectric nanoplatelets have been synthesized by a two-step method, and applied to the PVDF-based energy storage materials. Comprehensive tests and multi-physics simulations have been conducted on the electrical properties of materials. The electric displacement-electric field (D-E) hysteresis loops of the composites show that the discharge density of 6.987 J/cm3 ~ 2300 kV/cm has been achieved with a 10 wt% filler addition, namely 10Ag-NiMOF/PVDF, which indicates a 5.36 times increase in the discharge density. Finite element simulation further verifies the improvement of the displacement and electrical breakdown strength of the composites. This high performance indicates that both of the centrosymmetric lattice nanodomains of NiMOF and the electrons introduced by Ag nanoparticle would help induce greater polarization in the nanocomposite. Furthermore, the Coulomb blockade effect exerted by the Ag nanoparticle with an appropriate particle size and a fractional concentration can significantly improve the electrical breakdown strength. This 2D hybrid particle provides a novel idea for modifying dielectric composites for high storage device applications.
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•Ag Content-controlled ultra-thin 2D Ag-NiMOF ferroelectric nanoplatelets have been synthesized by a two-step method.•The discharge density of 6.987 J/cm3 ~ 2300 kV/cm has been achieved with a 10 wt% hybrid nanopalatets addition.•The centrosymmetric lattice nanodomains of NiMOF and the electrons introduced by Ag dots would help induce greater polarization in nanocomposite.•The Coulomb blockade effect exerted by the Ag dots with an appropriate size can significantly improve the electrical breakdown strength.
Quantitative detection of veterinary drug residues in animal-derived food is of great significance. In this work, a simple and label-free electrochemical aptasensor for the highly sensitive detection ...of chloramphenicol (CAP) in milk was successfully developed based on a new biosensing method, where the single- or few-layer Ti3C2 MXene nanosheets functionalized via the specific aptamer by self-assembly were used as electrode modifiers for a glassy carbon electrode (aptamer/Ti3C2 MXene/GCE). Differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy (SEM), atomic force microscope (AFM), and so on were utilized for electrochemical and morphological characterization. Under the optimized conditions, the constructed aptasensor exhibited excellent performance with a wider linearity to CAP in the range from 10 fM to 1 μM and a low detection limit of 1 fM. Aptamer/Ti3C2 MXene/GCE demonstrated remarkable selectivity over other potentially interfering antibiotics, as well as exceptional reproducibility and stability. In addition, the aptasensor was successfully applied to determine CAP in milk with acceptable recovery values of 96.13% to 108.15% and relative standard deviations below 9%. Therefore, the proposed electrochemical aptasensor is an excellent alternative for determining CAP in food samples.
The grafting of amino-POSS on the carbon fibers (CFs) surface was achieved through the reaction of the spiralphosphodicholor (SPDPC) grafted on the CFs surface with aminopropylphenyl polyhedral ...oligomeric silsesquioxane (amino-POSS). X-ray photoelectron spectroscopy (XPS) showed that the phosphorus, chlorine and silicon containing functional groups were obviously increased after the modifications. Both CFs grafted with SPDPC and CFs grafted with SPDPC plus amino-POSS have been used to prepare unsaturated polyester resin (UPR) composites. The grated SPDPC and grafted with a combined SPDPC and amino-POSS improved the interfacial performance of the CFs/UPR composites, respectively. Atomic force microscopy (AFM) results showed that the surface roughness of the CFs grafted with SPDPC was lower than that of the CFs grafted with a combined SPDPC and amino-POSS. Dynamic contact angle analysis of the CFs grafted with SPDPC showed higher wettability to UPR than that of the CFs grafted with a combined SPDPC and amino-POSS. Force modulation atomic force microscopy (FMAFM) and interlaminar shear strength (ILSS) were used to characterize the interfacial properties of the composites. After grafted with a combined SPDPC and amino-POSS, the ILSS of the composites was increased by 22.9% due to the well interfacial properties that were caused by the improvement of CFs surface roughness.
It is a long‐term goal in external insulation studies to determine the discharge voltages of complicated engineering gaps by simulation methods. Based on the one‐to‐one correspondence between air gap ...structure and the static electric field (EF) distribution, this paper characterizes the transmission tower gap configuration by spatial EF features, which were used for machine learning to achieve switching impulse discharge voltage prediction. An interelectrode path and a conical zone between the energized sub‐conductor and the crossarm or the tower window were considered as EF regions strongly associated with gap breakdown, where 73 parameters were extracted to construct a feature set. Taking 15 extra‐high voltage (EHV) transmission tower gaps as training samples, with different gap distances and tower configurations, their EF features were input to a support vector machine (SVM) for model training to establish the relationships with discharge voltages. The trained SVM model was used to predict the impulse discharge voltages of 20 EHV and ultra‐high voltage (UHV) transmission tower gaps. The prediction results with different feature dimensions and various sizes of conical zones were compared to the experimental values, which demonstrate similar variation trends and acceptable errors. This study contributes to realize insulation strength calculation of engineering gaps.
Rice protein is a high-quality plant-based protein source that is gluten-free, with high biological value and low allergenicity. However, the low solubility of rice protein not only affects its ...functional properties such as emulsification, gelling, and water-holding capacity but also greatly limits its applications in the food industry. Therefore, it is crucial to modify and improve the solubility of rice protein. In summary, this article discusses the underlying causes of the low solubility of rice protein, including the presence of high contents of hydrophobic amino acid residues, disulfide bonds, and intermolecular hydrogen bonds. Additionally, it covers the shortcomings of traditional modification methods and the latest compound improvement methods, compares various modification methods, and puts forward the best sustainable, economical, and environmentally friendly method. Finally, this article lists the uses of modified rice protein in dairy, meat, and baked goods, providing a reference for the extensive application of rice protein in the food industry.
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