The authors systematically describe the general principles of Kolsky bars, or split Hopkinson bars, which are widely used for obtaining dynamic material properties. Modifications are introduced for ...obtaining reliable data. Specific experiment design guidelines are provided to subject the specimen to desired testing conditions. Detailed Kolsky-bar examples are given for different classes of materials (brittle, ductile, soft, etc) and for different loading conditions (tension, torsion, triaxial, high/low temperatures, intermediate strain rate, etc). The Kolsky bars used for dynamic structural characterization are briefly introduced. A collection of dynamic properties of various materials under various testing conditions is included which may serve as a reference database. This book assists both beginners and experienced professionals in characterizing high-rate material response with high quality and consistency. Readers who may benefit from this work include university students, instructors, R D professionals, and scholars/engineers in solid mechanics, aerospace, civil and mechanical engineering, as well as materials science and engineering.
Cardiovascular diseases (CVDs) are the main cause of death among patients with type 2 diabetes mellitus (T2DM), particularly in low- and middle-income countries. To effectively prevent the ...development of CVDs in T2DM, considerable effort has been made to explore novel preventive approaches, individualized glycemic control and cardiovascular risk management (strict blood pressure and lipid control), together with recently developed glucose-lowering agents and lipid-lowering drugs. This review mainly addresses the important issues affecting the choice of antidiabetic agents and lipid, blood pressure and antiplatelet treatments considering the cardiovascular status of the patient. Finally, we also discuss the changes in therapy principles underlying CVDs in T2DM.
Hypochlorous acid (HOCl), a well-known universal disinfectant in clinical practice, plays important roles in immune systems of animal and human bodies. For understanding the roles of HOCl in living ...systems, a number of approaches, including chemiluminescence, colorimetric, electrochemical and chromatographic methods have been explored. For the detection of HOCl in live organisms, cutting-edge techniques, such as fluorescence/phosphorescence molecular probes, responsive nanoprobes, Raman and activatable photoacoustic sensors, have also been developed recently. In this review, the recent advances in the development of bioanalytical methods for detection of HOCl in environmental and biological specimens were summarized. More specifically, traditional techniques for assay of HOCl in bulk solution were initially discussed, and then fluorescence molecular probes, phosphorescence probes, responsive nanoprobes and other methods for HOCl detection were reviewed, which gives an overview of the developments and applications in bioanalytical methods for HOCl detection.
•Production and functions of HOCl in biological systems were introduced.•Recent development of bioanalytical methods for HOCl analysis was reviewed.•Performance for the detection of HOCl by fluorescence probes were compared.•Challenges and future outlooks for the development of bioanalytical methods for HOCl were discussed.
Selective laser melting (SLM) is an attractive rapid prototyping technology for the fabrication of metallic components with complex structure and high performance. Aluminum alloy, one of the most ...pervasive structural materials, is well known for high specific strength and good corrosion resistance. But the poor laser formability of aluminum alloy restricts its application. There are problems such as limited processable materials, immature process conditions and metallurgical defects on SLM processing aluminum alloys. Some efforts have been made to solve the above problems. This paper discusses the current research status both related to the scientific understanding and technology applications. The paper begins with a brief introduction of basic concepts of aluminum alloys and technology characterization of laser selective melting. In addition, solidification theory of SLM process and formation mechanism of metallurgical defects are discussed. Then, the current research status of microstructure, properties and heat treatment of SLM processing aluminum alloys is systematically reviewed respectively. Lastly, a future outlook is given at the end of this review paper.
Searching for the signature of the violation of chiral charge conservation in solids has inspired a growing passion for the magneto-transport in topological semimetals. One of the open questions is ...how the conductivity depends on magnetic fields in a semimetal phase when the Fermi energy crosses the Weyl nodes. Here, we study both the longitudinal and transverse magnetoconductivity of a topological Weyl semimetal near the Weyl nodes with the help of a two-node model that includes all the topological semimetal properties. In the semimetal phase, the Fermi energy crosses only the 0th Landau bands in magnetic fields. For a finite potential range of impurities, it is found that both the longitudinal and transverse magnetoconductivity are positive and linear at the Weyl nodes, leading to an anisotropic and negative magnetoresistivity. The longitudinal magnetoconductivity depends on the potential range of impurities. The longitudinal conductivity remains finite at zero field, even though the density of states vanishes at the Weyl nodes. This work establishes a relation between the linear magnetoconductivity and the intrinsic topological Weyl semimetal phase.
Finite-momentum Cooper pairing is an unconventional form of superconductivity that is widely believed to require finite magnetization. Altermagnetism is an emerging magnetic phase with highly ...anisotropic spin-splitting of specific symmetries, but zero net magnetization. Here, we study Cooper pairing in metallic altermagnets connected to conventional s-wave superconductors. Remarkably, we find that the Cooper pairs induced in the altermagnets acquire a finite center-of-mass momentum, despite the zero net magnetization in the system. This anomalous Cooper-pair momentum strongly depends on the propagation direction and exhibits unusual symmetric patterns. Furthermore, it yields several unique features: (i) highly orientation-dependent oscillations in the order parameter, (ii) controllable 0-π transitions in the Josephson supercurrent, (iii) large-oblique-angle Cooper-pair transfer trajectories in junctions parallel with the direction where spin splitting vanishes, and (iv) distinct Fraunhofer patterns in junctions oriented along different directions. Finally, we discuss the implementation of our predictions in candidate materials such as RuO
and KRu
O
.
The influence of the microstructure on mechanical properties of AlSi10Mg fabricated by casting and selective laser melting (SLM) were investigated and contrasted in this work, with an emphasis on ...understanding the forming mechanism. The microstructure, phase structure and mechanical properties were characterized by scanning electron microscopy/field-emission Transmission Electron Microscopy (SEM/TEM), X-Ray Diffraction (XRD), tensile and fatigue tests. The results indicated that the SLM AlSi10Mg exhibited a supersaturated Si network structure precipitated along α-Al cell. Brittle β-Al5FeSi and π-Al8FeMg3Si6 phases were found in the as-cast and SLM AlSi10Mg respectively due to different thermal histories during processing. The SLM AlSi10Mg showed higher tensile strength but lower elongation than the casting, as the result of grain refinement and tortuous crack path. The fatigue results revealed that unmelted powder, oxide inclusion and pores can considerably degrade the fatigue properties for the SLM AlSi10Mg. The SLM process offered a new method for material processing that would avoid harmful Fe-bearing intermetallic compounds and refine the microstructures for enhancing strength.
Producing hydrogen fuel through environmentally friendly electrochemical and solar-driven photoelectrochemical (PEC) water splitting is a very promising approach for providing affordable clean ...energy. The scalable and sustainable production of hydrogen demands efficient and robust earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) beyond platinum and other precious-metal catalysts. This review provides an overview of molybdenum disulfide (MoS2) and related compounds as inexpensive alternative electrocatalysts for HER catalysis and PEC water splitting. After a background introduction, we discuss the important approaches to improving the intrinsic catalytic activity and overall catalytic performance of MoS2. We further review the key developments in combining MoS2 with semiconductors for integrated PEC systems for direct solar-to-fuel conversion and provide insights on how to design efficient solar-driven water-splitting systems. Our perspectives on the key challenges and future directions for development of earth-abundant HER electrocatalysts and PEC water splitting are also discussed.
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Generating hydrogen fuel through electrochemical and solar-driven photoelectrochemical (PEC) water splitting is a very promising approach to providing affordable clean energy, reducing our reliance on fossil fuels, and mitigating the impact of climate change. The sustainable production of hydrogen demands efficient and robust earth-abundant catalysts that are not based on platinum and other precious metals for the hydrogen evolution reaction (HER).
This review focuses on molybdenum disulfide (MoS2) and related compounds as inexpensive alternatives for HER catalysis and PEC water splitting. We discuss key approaches to improving the intrinsic catalytic activity and overall catalytic performance and the developments in combining MoS2 with semiconductors to realize solar-to-fuel conversion. We also discuss how to design efficient PEC water-splitting systems, as well as our perspectives on the key challenges and future directions for developing earth-abundant HER electrocatalysts and PEC water splitting.
This review provides an overview of molybdenum disulfide (MoS2) and related compounds as inexpensive alternatives for hydrogen evolution reaction electrocatalysis and solar-driven photoelectrochemical water splitting toward the goals of producing hydrogen fuel to provide affordable clean energy. Important approaches to improving the intrinsic catalytic activity, developments in combining MoS2 with semiconductors to design efficient water-splitting systems, and perspectives on the challenges and future directions are discussed.
Selective laser melting, due to the high energy density input and the small interaction time (106 K/s), can result in an ultrafine microstructure and excellent mechanical properties. However, due to ...the nonuniform nature of the temperature distribution and the transition from liquid to solid, high residual stresses exist. High residual stresses in the parts can increase the risk of material distortion and cause many problems, such as dimensional inaccuracy or cracks. This work systematically investigated the influence of annealing on the microstructure and mechanical properties of SLM-processed AlSi7Mg alloy parts. The residual stresses relaxed significantly after annealing. The Vickers hardness and the tensile stress greatly reduced, while the elongation increased. The fracture mode of the as-fabricated sample was ductile and brittle mixed fracture, whereas the fracture morphology of the annealed sample presented many more dimples, and the elongation also increased, which indicated the ductile mode.
AlSi7Mg is one of the most widely used aluminum alloys. However, its moderate strength limits its use as a structural material for critical parts. Most mechanisms used to strengthen the material ...sacrifice its ductility. In situ reactions during the selective laser melting (SLM) process rectify the trade-off by introducing dislocations around the subgrain boundaries and nano-twin planes in the by-product Si phase. This work was the first attempt to reinforce AlSi7Mg by nano-SiC particles fabricated by SLM. In addition, the rapid solidification rate caused solid solution strengthening, fine-grain strengthening and precipitation strengthening, which also contributed to the mechanical properties.
•Improved mechanical properties of SiCp/AlSi7Mg composites were fabricated.•Nano-Al4C3 and Si with nano-twin planes formed by the in situ reaction.•Dislocations around the cell boundaries contributed to the high strain.•Solid solution and fine-grain strengthening were main strengthening mechanisms.
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