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Background. Apoptosis plays an important role in various diseases, including spinal cord injury (SCI). Hyperbaric oxygen (HBO) and erythropoietin (EPO) promote the recovery from SCI, but the relationship between apoptosis [...]

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Regulation of the atomic distribution is crucial for the development of atomically dispersed electrocatalysts. In this study, atomic Ru coordinated by channel ammonia in V-doped tungsten bronze (Ru/V-NHWO, Ru 0.44 wt%, V 0.45 wt%) was used as a high-performance catalyst for the hydrogen evolution reaction (HER), demonstrating remarkable mass activity in a wide pH range. Atomic Ru with a regulated spatial distribution and electronic structure was achieved owing to its unique coordination with the ammonia species in the hexagonal channels of V-NHWO. V doping in NHWO led to enhanced intrinsic activity and conductivity. Theoretical calculations revealed that the multichannel, vertically integrated Ru sites in the V-doped channels, as well as the coexisting Ru sites without multichannels or V-doping, improved the free energy of water dissociation and hydrogen sorption, which boosted the HER activity. Our study paves a new way for constructing atomically dispersed materials with a regulated spatial distribution for diverse applications.

The discovery of single-atom catalysts (SACs) represents a groundbreaking advancement in the field of catalysis over the past decades. With the in-depth exploration of relevant structure-activity relationships, the metal−support interaction (MSI) is widely adopted to elucidate variations in electronic structure and coordination configuration of atomic active sites on various kinds of supports. Herein, we briefly summarize the metal oxide supports for SACs fabrication, including the distinctive characteristics of metal oxide supports, enlightening advancements in metal oxide support-based SACs (MO-SACs), feasible preparation methods for MO-SACs and effective regulation strategies of MSI effect in MO-SACs. In addition, we present our viewpoints and outlook in this field to stimulate rational design and construction of novel MO-SACs applied in diverse renewable energy devices, while some universal suggestions are sincerely given to provoke thoughtful considerations during the research process.

Medium voltage (MV) SiC devices facilitate direct (without 50-/60-Hz transformer) connection of the power electronics converter to the MV grid using simple topology. Compared to the insulation design of MV inductors that have been widely used in the power system, the insulation design of the MV converter filter inductors has new challenges. Particularly, the grid impact on insulation requirements on converter filter inductors is rarely discussed. This article introduces the insulation design of a grid-side filter inductor for a 13.8-kV power conditioning system converter. The grid insulation requirements, including the short-duration power frequency overvoltage and the lightning impulse voltage, are considered in the design. To meet the requirements, the layer-to-layer insulation, winding-to-core/ground insulation, the air gap discharge between the winding and the core, the local electric field, as well as the interturn transient voltage distribution are considered. The designed inductors are validated by the 46 kV (>1 min) dc hi-pot test, 12-kV ac partial discharge test, one-hour single-phase converter full rating test, as well as three-phase converter full rating test.

The optimal exponentials of thickness in the geometry rigidity inequality of shells represent the geometry rigidity of the shells. The author obtains that the lower bounds of the optimal exponentials are 4/3, 3/2, and 1, for hyperbolic shells, parabolic shells, and elliptic shells, respectively, through the construction of the Ansätze.

Medium-frequency transformer (MFT) dc bias is critical for the safe operation of dual-active-bridge (DAB) converters. To analyze the dc bias, expressions of dc bias are derived for SiC MOSFET DAB converters. It shows that the dc bias is a current source in steady state; thus, a dc bias current capacity is defined and used as a design constraint in the optimization of MFT. The dc bias current capacity is related to core materials, geometric parameters, and flux density, which is analyzed with analytical expression. Optimization equations with geometric variables are derived, which can be solved theoretically or numerically for both interleaved winding (IW) and separated winding (SW) MFT without and/or with leakage inductance design. Based on the optimization equations, different MFT designs for a 150-kW SiC MOSFET DAB converter are compared on the aspects of core materials, winding structures, and without/with leakage inductance design. The combination of IW structure MFT with auxiliary phase shift inductors is chosen, and the assembled prototype is tested with the 150-kW DAB converter. The designed dc bias capacity, temperature rise, and efficiency are verified.

The development of catalysts free of platinum-group metals with a high performance for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells is a grand challenge. Herein, we report zeolitic imidazolate framework-8-based Co, N, and S tridoped carbon frameworks (Co–N–S CFs) with high ORR catalytic activity and remarkable durability in an alkaline medium. Results indicate that the high ORR performance of the Co–N–S CFs could be attributed to the unique 3D structure of carbon frames, the synergistic effect among Co, N, and S, and its high electron conductivity. It is also found that the N and S doped heteroatoms can anchor Co atoms by forming CoNxand CoSxactive sites for a highly efficient ORR. The results obtained here can help in the design and understanding of the cost-effective highly active Pt-free electrocatalysts.

Aqueous zinc ion batteries are excellent energy storage devices with high safety and low cost. However, the corrosion reaction and zinc dendrite formation occurring on the surface of zinc anodes are hindering their further development. To solve the problems, zirconium acetate (ZA) was used as an electrolyte additive in the ZnSO4electrolyte. Attributing to the higher electro-positivity of Zr4+than Zn2+, these high valence metal cations preferentially adsorb onto the surface of metallic zinc, shielding parasitic reactions between zinc and electrolyte, reshaping the electric field distribution, and directing preferential homogeneous deposition of Zn-ions on the Zn (002) crystal plane. Furthermore, the adsorption of Zr4+on the Zn metal after electrochemical cycles can enhance the energy barrier of zinc atom diffusion, resulting in high resistance of corrosion and manipulation of the Zn2+nucleation configuration. Attributing to these properties, the Zn//Zn symmetric cell with an electrolyte additive of ZA was able to cycle for 400 h under an extremely high current density of 40 mA cm–2with an area capacity of 2 mAh cm–2. Meanwhile, the MnO2//Zn coin cell still had 81.7 mAh g–1(85% retention of capacity) after 850 cycles under a current density of 1 A g–1.

Achiral Schiff base complexes as catalysts for asymmetric sulfoxidation in the presence of serum albumins.

The authors establish weighted L2-estimates of solutions for the damped wave equations with variable coefficients utt− divA(x)∇u+aut= 0 in ℝnunder the assumption a(x) ≥ a0[1+ρ(x)]−l, where a0> 0, l< 1, ρ(x) is the distance function of the metric g= A−1(x) on ℝn. The authors show that these weighted L2-estimates are closely related to the geometrical properties of the metric g= A−1(x).

This paper considers the energy decay of the wave equation with variable coefficients in an exterior domain. The damping is put on partly the boundary and partly on the interior of the domain. The energy decay results are established by Riemannian geometry method.

The authors study decay properties of solutions for a viscoelastic wave equation with variable coefficients and a nonlinear boundary damping by the differential geometric approach.

As a group of researchers and artists, we have collaborated on a science-art project that converts seismic and hydroacoustic data into immersive digital artworks, revealing the hidden realm of ocean soundscape. We integrated artistic methodologies to produce soundtracks and videos from seismic waveforms recorded in the ocean, which enables the general public to gain a multisensory experience of the scientific data studied by specialists. Through exhibitions in multiple venues, our interdisciplinary approach was well received by diverse audiences, showcasing the potential for creative representations of scientific information., (© 2024 The Author(s).)