• Cox Iqbal posted an update 6 months, 2 weeks ago

    Linear polymers for many materials applications are popularly produced via step-growth polymerizations of different pairs of A2 and B2 monomers. However, achieving high molecular weights during the synthesis is dramatically limited by the required stoichiometric balance of A and B reactive groups when reactivity is considered unchanged during the polymerization. This short review summarizes the recent progress on using Friedel-Crafts polycondensation reactions to produce high-molecular-weight linear polymers via the reaction-enhanced reactivity of intermediate (RERI) mechanism, in which the reaction of one functional group in the bifunctional monomer spontaneously increases the reactivity of the other functional group on the monoreacted intermediate for faster consumption and connection into polymer chains. Thus, using an excess amount of this monomer produces linear polymers in high molecular weights. Both Friedel-Crafts acylation and hydroxyalkylation reactions have been reported for syntheses of long polymer chains under nonstoichiometric conditions, although the focus is to illustrate the significant progress of applying Friedel-Crafts hydroxyalkylation reactions to produce linear polymers with high molecular weights and varied compositions.Water is critical for all lives to thrive. Access to potable and safe water has been argued to rank top among the prerequisites for defining the standard of living of a nation. However, there is a global decline in water quality due to human activities and other factors that severely impact freshwater resources such as saltwater intrusion and natural disasters. It has been pointed out that the millions of liters of industrial and domestic wastewater generated globally have the potential to help mitigate water scarcity if it is appropriately captured and remediated. Among the many initiatives to increase access to clean water, the scientific community has focused on wastewater remediation through the utilization of bioderived materials, such as nanocellulosics. Nanocellulosics, derived from cellulose, have the advantages of being ubiquitous, nontoxic, and excellent adsorbents. Furthermore, the surface properties of nanocellulosic materials can easily be modified. These advantages make them promising materials for water remediation applications. This perspective highlights the most important new developments in the application of nanocellulosics in water treatment technologies, such as membrane, adsorption, sensors, and flocculants/coagulants. We also identify where further work is urgently required for the widespread industrial application of nanocellulosics in wastewater treatment.In this work, an analogue of electromagnetically induced transparency (EIT) is excited by a periodic unit consisting of a silicon rectangular bar resonator and a silicon ring resonator in terahertz (THz). The analogue of the EIT effect can be well excited by coupling of the “bright mode” and the “dark mode” supported by the bar and the ring, respectively. Using the semimetallic properties of graphene, active control of the EIT-like effect can be realized by integrating a monolayer graphene into THz metamaterials. By adjusting the Fermi energy of graphene, the resonating electron distribution changes in the dielectric structures, resulting in the varying of the EIT-like effect. The transmission can be modulated from 0.9 to 0.3 with the Fermi energy of graphene placed under the ring resonator mold varying from 0 to 0.6 eV, while a modulation range of 0.9-0.3 corresponds to Fermi energy from 0 to 0.3 eV when graphene is placed under the rectangular bar resonator. Our results may provide potential applications in slow light devices and an ultrafast optical signal.We study the structural, electronic, and magnetic properties of the antiferromagnetic-layered oxyarsenide (LaO)MnAs system from the first-principle calculation. The increasing Hubbard energy (U) in the Mn 3d orbital induces the increasing local-symmetry distortions (LSDs) in MnAs4 and OLa4 tetrahedra. The LSD in MnAs4 tetrahedra is possibly promoted by the second-order Jahn-Teller effect in the Mn 3d orbital. https://www.selleckchem.com/products/upadacitinib.html Furthermore, the increasing U also escalates the bandgap (Eg) and the magnetic moment of Mn (μMn). The value of U = 1 eV is the most appropriate by considering the structural properties. This value leads to Eg and μMn of 0.834 eV and 4.31 μB, respectively. The calculated μMn is lower than the theoretical value for the high-spin state of Mn 3d (5 μB) due to the hybridization between Mn 3d and As 4p states. However, d xy states are localized and show the weakest hybridization with valence As 4p states. The Mott-insulating behavior in the system is characterized by the Eg transition between the valence and conduction d zx /d zy states. This work shows new physical insights for advanced functional device applications, such as spintronics.In this work, Langmuir-Blodgett (LB) composite thin films were successfully prepared using black phosphorus nanosheets (BPNS) and dye molecules. Black phosphorus (BP) was first exfoliated in isopropanol solution to form BPNS, and then, BPNS were modified with 4-azidobenzoic acid (Az-BPNS) to improve their stability. The characterization results showed that the synthesized Az-BPNS-dye LB films have a uniform and ordered structure. In addition, the synthesized Az-BPNS-dye LB films exhibit excellent photoelectrochemical performance, and Az-BPNS-methylene blue (MB) produces higher photocurrent compared to Az-BPNS-Neutral red (NR) films. The current work shows an effective way to prepare functionalized BP-based materials and provide evidence for their application in optoelectronic devices.Steam traps in large facilities need continuous maintenance to prevent corrosion and other damage that could pose a considerable threat to a facility and its workers. However, a significant amount of human resources is required for the maintenance of steam traps. An automatic method to inform stakeholders regarding maintenance cycles will be beneficial for the maintenance process. Therefore, an optimal maintenance priority decision model is developed in this study to establish an efficient steam trap management system. First, the frequency of failures, installation locations, and specifications of steam traps were determined as parameters causing a failure. A relative score and conversion score are calculated for each parameter. The final conversion score is the sum of the conversion score multiplied by the corresponding steam trap data weight factor. Steam traps within the range requiring inspection are classified as high priority cases. Experimental results confirmed that the failure accuracy rate is approximately 95%, and the average failure error rate is within 3%.

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