Numerical Modelling of Positive Surface Discharges in C-C4F8/CF3I/N2 Gas Mixture under Non-Uniform Field

As an environmentally friendly gas with good insulation and stable chemical properties, CF3I gas mixture is considered as a potential alternative to SF6 gas to compensate for the shortcomings of SF6 gas as a greenhouse gas. This article attempts to study the CF3I ternary gas mixtures with c-C4F8 and N2 by considering the process of streamer development in surface discharge. The model of surface discharge in CF3I gas mixture under DC voltage was established by COMSOL, and the drift-diffusion equations of particles was solved to show the discharge process, and the changes of electric field and particle concentration, etc. during the development of streamer were obtained, which provides the theoretical basis for the reliable diagnosis of partial discharge. On this basis, the model is compared with models for two other different gases (SF6/N2, artificial air) in terms of particle characteristics, streamer characteristics and streamer branches characteristics. Finally, it is concluded that under this model, although the insulation characteristics in CF3I gas mixture are weaker than those in SF6, the difference is not large and both are much better than those in artificial air, so c-C4F8/CF3I can be considered as a potential substitute for SF6.

Multifunctional Coatings of Titanium Implants Toward Promoting Osseointegration and Preventing Infection: Recent Developments

Titanium and its alloys are dominant material for orthopedic/dental implants due to their stable chemical properties and good biocompatibility. However, aseptic loosening and peri-implant infection remain problems that may lead to implant removal eventually. The ideal orthopedic implant should possess both osteogenic and antibacterial properties and do proper assistance to in situ inflammatory cells for anti-microbe and tissue repair. Recent advances in surface modification have provided various strategies to procure the harmonious relationship between implant and its microenvironment. In this review, we provide an overview of the latest strategies to endow titanium implants with bio-function and anti-infection properties. We state the methods they use to preparing these efficient surfaces and offer further insight into the interaction between these devices and the local biological environment. Finally, we discuss the unmet needs and current challenges in the development of ideal materials for bone implantation.

Progress in the Application of Carbon Dots-Based Nanozymes

As functional nanomaterials with simulating enzyme-like properties, nanozymes can not only overcome the inherent limitations of natural enzymes in terms of stability and preparation cost but also possess design, versatility, maneuverability, and applicability of nanomaterials. Therefore, they can be combined with other materials to form composite nanomaterials with superior performance, which has garnered considerable attention. Carbon dots (CDs) are an ideal choice for these composite materials due to their unique physical and chemical properties, such as excellent water dispersion, stable chemical inertness, high photobleaching resistance, and superior surface engineering. With the continuous emergence of various CDs-based nanozymes, it is vital to thoroughly understand their working principle, performance evaluation, and application scope. This review comprehensively discusses the recent advantages and disadvantages of CDs-based nanozymes in biomedicine, catalysis, sensing, detection aspects. It is expected to provide valuable insights into developing novel CDs-based nanozymes.

Fast Fabrication of Conductive Copper Structure on Glass Material Using Laser-Induced Chemical Liquid Phase Deposition

Glass is a very stable material at room temperature and has good resistance to gas, bacteria, and organisms. Due to the development of the electronic industry, the industrial demand for creating a conductive pattern on glass is increasing rapidly. To create conductive circuit patterns on the glass surface, non-contact methods based on high energy sources or chemical methods are generally used. However, these methods have disadvantages such as low conductivity, high cost, and size limitations. Processes such as LCLD (laser-induced chemical liquid phase deposition) have been widely studied to solve this problem. However, it has a fatal disadvantage of being slow. Therefore, in this study, various process changes were attempted to improve productivity and conductivity. In particular, sufficient thermal energy was supplied with high laser power for a stable chemical reduction, and the scanning path was changed in various shapes to minimize the ablation that occurs at this time. Through this, it was possible to disperse the overlapped laser energy of high power to widen the activation area of the reduction reaction. With this proposed LCLD process, it is possible to achieve good productivity and fabricate conductive circuit patterns faster than in previous studies.

Cobalt oxide-based nanomaterial for electrochemical sensor applications

Amongst the extended list of metal oxides, Co3O4 has gained envisioned attention in various technological fields. It has a proven record of promising material in optical, optoelectronics, sciences, engineering, medicines and biological fields of studies. Co3O4 is a promising candidate due to its large surface-to-volume ratio, simple preparation methods, higher well-defined electrochemical redox activity, high theoretical capacity, low cost, and stable chemical states. Co3O4 has been used in various applications such as fuel cells, photoelectrochemical water splitting, solar cells, supercapacitors, batteries and electrochemical sensors due to its applicability in various fields. It has shown promising outcomes as an electrochemical sensor in various areas such as in the detection of water contamination, as physiological molecule detectors etc. this mini-review summarizes the fields of contaminated water, as fuel and also in the physiological system.

Reprocessable Photodeformable Azobenzene Polymers

Photodeformable azobenzene (azo) polymers are a class of smart polymers that can efficiently convert light energy into mechanical power, holding great promise in various photoactuating applications. They are typically of crosslinked polymer networks with highly oriented azo mesogens embedded inside. Upon exposure to the light of appropriate wavelength, they experience dramatic order parameter change following the configuration change of the azo units. This could result in the generation and accumulation of the gradient microscopic photomechanical force in the crosslinked polymer networks, thus leading to their macroscopic deformation. So far, a great number of photodeformable azo polymers have been developed, including some unoriented ones showing photodeformation based on different mechanisms. Among them, photodeformable azo polymers with dynamic crosslinking networks (and some uncrosslinked ones) have aroused particular interest recently because of their obvious advantages over those with stable chemical crosslinking structures such as high recyclability and reprocessability. In this paper, I provide a detailed overview of the recent progress in such reprocessable photodeformable polymers. In addition, some challenges and perspectives are also presented.

Robust Conductive Hydrogels with Ultrafast Self-Recovery and Nearly Zero Response Hysteresis for Epidermal Sensors

Robust conductive hydrogels are in great demand for the practical applications of smart soft robots, epidermal electronics, and human–machine interactions. We successfully prepared nanoparticles enhanced polyacrylamide/hydroxypropyl guar gum/acryloyl-grafted chitosan quaternary ammonium salt/calcium ions/SiO2 nanoparticles (PHC/Ca2+/SiO2 NPs) conductive hydrogels. Owing to the stable chemical and physical hybrid crosslinking networks and reversible non-covalent interactions, the PHC/Ca2+/SiO2 NPs conductive hydrogel showed good conductivity (~3.39 S/m), excellent toughness (6.71 MJ/m3), high stretchability (2256%), fast self-recovery (80% within 10 s, and 100% within 30 s), and good fatigue resistance. The maximum gauge factor as high as 66.99 was obtained, with a wide detectable strain range (from 0.25% to 500% strain), the fast response (25.00 ms) and recovery time (86.12 ms), excellent negligible response hysteresis, and good response stability. The applications of monitoring the human’s body movements were demonstrated, such as wrist bending and pulse tracking.

An Analytical Method for Gas Flow Measurement Using Conservative Chemical Elements

Mass flow meters (MFMs) are widely used to secure reliable flow rates based on the mass value of the gas being measured. However, chemical reactions produce various kinds of gases, and their composition also changes in real time. Thus, there may be a large deviation in the gas flow if the gases’ composition and its mixing ratio are not known. In this study, we derived a gas flow rate measurement method using a chemically stable chemical specie and verified the precision of the proposed method through comparative analysis with an MFM. The flow rate by this method showed reliable results in both single and mixed gases. Notably, the results were within ±2.74% of the injected flowrate values in the gas mixtures. This method is expected to be able to fundamentally overcome the limitations of the mechanical flowmeter because it is not affected by changes in gas composition or mixing ratio during the reaction.

Application of Fuel Ash as a Microfiller in Cement Dispersion Systems

The paper shows studies of modified cement compositions with micro-filler. As such a micro-filler, an ash product is used - an activated waste of an ash-and-slag mixture. The enriched aluminosilicate waste is characterized by a fairly stable chemical and particle size distribution. The used activation of the ash product allows for a more dense packing of particles in the composition of the binder dispersed system. The high dispersion of the ash component requires additional plasticization of the dispersed system. Despite the fact that during the activation process the destruction of large-pore particles remaining after flotation occurs, the introduction of a plasticizer also improves the rheological characteristics of the compositions, and, consequently, increases the strength and density of the modified cement stone with the addition of a microfiller.