Npg Asia Materials最新文献

The intermediate-range order of covalently bonded glasses has been extensively studied in terms of their diffraction peaks observed at low scattering angles; these peaks are called the first sharp diffraction peaks (FSDPs). Although the atomic density fluctuations originating from the quasilattice planes are a critical scientific target, direct experimental observations of these fluctuations are still lacking. Here, we report the direct observation of the atomic density fluctuations in silica glass by energy-filtered angstrom-beam electron diffraction. The correspondence between the local electron diffraction patterns of FSDPs and the atomic configurations constructed based on the X-ray and neutron diffraction results revealed that the local atomic density fluctuations originated from the quasi-periodic alternating arrangements of the columnar chain-like atomic configurations and interstitial tubular voids, as in crystals. We also discovered longer-range fluctuations associated with the shoulder of the FSDP on the low-Q side. The hierarchical fluctuations inherent in materials could aid in the elucidation of their properties and performance.

All-inorganic lead halide perovskites (LHPs) and their use in optoelectronic devices have been widely explored because they are more thermally stable than their hybrid organic‒inorganic counterparts. However, the active perovskite phases of some inorganic LHPs are metastable at room temperature due to the critical structural tolerance factor. For example, black phase CsPbI₃ is easily transformed back to the nonperovskite yellow phase at ambient temperature. Much attention has been paid to improving the phase stabilities of inorganic LHPs, especially those with high solar cell efficiencies. Herein, we discussed the origin of phase stability for CsPbI₃ and the strategies used to stabilize the cubic (α) phase. We also assessed the CsPbI₃ black β/γ phases that are relatively stable at nearly room temperature. Furthermore, we determined the relationship between phase stabilization and defect passivation and reviewed the growing trend in solar cell efficiency based on black phase CsPbI₃. Finally, we provide perspectives for future research related to the quest for optimum device efficiency and green energy.

Mussel periostracum, a nonliving multifunctional gel that covers the rigid inorganic shells of mussels, provides protection against mechanical impacts, biofouling, and corrosion in harsh ocean environments. The inner part of the periostracum, which emerges from biological tissues, functions as a natural interface between tissue and inorganic materials. The periostracum shows significant potential for application in implantable devices that provide interfaces; however, this system remains unexplored. In this study, we revealed that the inner periostracum performs graded mechanical functions and efficiently dissipates energy to accommodate differences in stiffness and stress types on both sides. On the tissue end, the lightly pigmented periostracum exhibits extensibility and energy dissipation under repetitive tension. This process was facilitated by the slipping and reassembly of β-strands in the discovered major proteins, which we named periostracin proteins. On the shell end, the highly pigmented, mineralized, and porous segment of the periostracum provided stiffness and cushioned against compressive stresses exerted by the shell valves during closure. These findings offer a novel possibilities for the design of interfaces that bridge human tissue and devices.

Understanding the nucleation mechanism in glass is crucial for the development of new glass-ceramic materials. Herein, we report the structure of a commercially important glass-ceramic ZrO₂-doped lithium aluminosilicate system during its initial nucleation stage. We conducted an X-ray multiscale analysis, and this analysis was used to observe the structure from the atomic to the nanometer scale by using diffraction, small-angle scattering, absorption, and anomalous scattering techniques. The inherent phase separation between the Zr-rich and Zr-poor regions in the pristine glass was enhanced by thermal treatment without changing the spatial geometry at the nanoscale. Element-specific pair distribution function analysis using anomalous X-ray scattering data showed the formation of a liquid ZrO₂-like local structural motif and edge sharing between the ZrO_x polyhedra and (Si/Al)O₄ tetrahedra during the initial nucleation stage. Furthermore, the local structure of the Zr⁴⁺ ions resembled a cubic or tetragonal ZrO₂ crystalline phase and formed after 2 h of annealing the pristine glass. Therefore, the Zr-centric periodic structure formed in the early stage of nucleation was potentially the initial crystal nucleus for the Zr-doped lithium aluminosilicate glass-ceramic.

Patients suffering from osteoporotic fractures often require effective fixation and subsequent bone repair. However, the currently available materials are functionally limited and often fail to improve outcomes in this patient population. In this study, we developed orthopedic adhesives doped with romosozumab-loaded mesoporous bioactive glass nanoparticles to aid in osteoporotic fracture fixation and restore dysregulated bone homeostasis. These adhesives were designed to promote osteoblast formation while simultaneously inhibiting osteoclastic bone-resorbing activity, thus working synergistically to promote the healing of osteoporotic fractures. Orthopedic adhesives exhibit injectability, reversible adhesiveness, and malleability, enhancing their adaptability to complex clinical scenarios. Furthermore, the release of romosozumab from mesoporous bioactive glass nanoparticles accelerated osteogenesis and inhibited osteoclastogenesis, delaying the bone resorption process. This dual action contributes to the regulation of bone regeneration and remodeling. Notably, our orthopedic adhesive could restore the disrupted bone homeostasis associated with osteoporotic fractures.

Zinc-ion hybrid supercapacitors (ZHSCs) are attracting significant attention due to their high energies/power densities, safety, and low cost. In this review, recent advances in the development of ZHSCs are summarized. Particular emphasis is placed on state-of-the-art cathodes (including carbon, metal oxides, MXenes, and redox-active polymers), anodes (including Zn-based composites and Zn-free materials) and electrolytes for ZHSCs. Furthermore, the latest research on functional ZHSC devices with miniaturized ZHSCs, fiber-shaped ZHSCs, self-chargeable ZHSCs and self-healing devices is reported. Finally, further developments with ZHSCs are envisaged for future research in this thriving field.

In this study, using the Pt/Cr₂O₃/Pt epitaxial trilayer, we demonstrate the giant voltage modulation of the antiferromagnetic spin reversal and the voltage-induced 180° switching of the Néel vector in maintaining a permanent magnetic field. We obtained a significant modulation efficiency of the switching field, Δμ₀H_SW/ΔV (Δμ₀H_SW/ΔE), reaching a maximum of −500 mT/V (−4.80 T nm/V); this value was more than 50 times greater than that of the ferromagnetic-based counterparts. From the temperature dependence of the modulation efficiency, X-ray magnetic circular dichroism measurements and first-principles calculations, we showed that the origin of the giant modulation efficiency relied on the electric field modulation of the net magnetization due to the magnetoelectric effect. From the first-principles calculation and the thickness effect on the offset electric field, we found that the interfacial magnetoelectric effect emerged. Our demonstration reveals the energy-efficient and widely applicable operation of an antiferromagnetic spin based on a mechanism distinct from magnetic anisotropy control.

Studying the properties of thermoelectric materials needs substantial effort owing to the interplay of the trade-off relationships among the influential parameters. In view of this issue, artificial intelligence has recently been used to investigate and optimize thermoelectric materials. Here, we used Bayesian optimization to improve the thermoelectric properties of multicomponent III–V materials; this domain warrants comprehensive investigation due to the need to simultaneously control multiple parameters. We designated the figure of merit ZT as the objective function to improve and search for a five-dimensional space comprising the composition of InGaAsSb thin films, dopant concentration, and film-deposition temperatures. After six Bayesian optimization cycles, ZT exhibited an approximately threefold improvement compared to its values obtained in the random initial experimental trials. Additional analysis employing Gaussian process regression elucidated that a high In composition and low substrate temperature were particularly effective at increasing ZT. The optimal substrate temperature (205 °C) demonstrated the potential for depositing InGaAsSb thermoelectric thin films onto plastic substrates. These findings not only promote the development of thermoelectric devices based on III–V semiconductors but also highlight the effectiveness of using Bayesian optimization for multicomponent materials.

The mechanism of energy loss due to magnetostriction in soft magnetic materials was analytically formulated, and our experiments validated this formulation. The viscosity of magnetic materials causes the resistive force acting on magnetic domain walls through strain due to magnetostriction, and magnetic energy is eventually dissipated by friction even without eddy currents. This energy loss mechanism explains the frequency dependence of the excess loss observed in the experiments, and the excess loss is dominated by the contribution of magnetostriction when the magnetostriction constant exceeds approximately 20 ppm. The random anisotropy model was extended by considering the effect of local magnetostriction as a correction to the magnetocrystalline anisotropy. The effect of magnetostriction was considerably suppressed by the exchange-averaging effect. The estimated effective random magnetoelastic anisotropy for nanocrystalline α-Fe reached as low as 18.6 J/m³, but this static effect could not explain the high excess loss at high frequencies observed in the experiments. The results of this research could provide new design criteria for high-performance soft magnetic materials based on low magnetostriction to reduce the excess loss.

Physical factors in the cellular microenvironment have critical effects on stem cell differentiation. The utilization of physical factors to promote the osteogenic differentiation of stem cells has been established as a new strategy for developing bone tissue engineering scaffolds. In this context, scaffolds with multiscale anisotropy are considered to possess biomimetic properties, which are advantageous for their biological performance. In the present study, a novel magnetic anisotropic hydrogel (MAH) with magnetic and topographic anisotropy was designed by combining static magnetic field-induced magnetic nanomaterials and a hydrogel. In in vitro studies, the MAH exhibited excellent biocompatibility and osteogenic bioactivity. The alkaline phosphatase activity and the expression of osteogenic-related genes and proteins induced by the MAH were greater than those induced by the pure PEGDA–GelMA hydrogel (PGH) and the magnetic isotropic hydrogel (MIH). In addition, the present study revealed that the dual anisotropic properties of the MAH activated the NOTCH1/2 pathway by upregulating SNHG5 and downstream SIRT6, which modulates the level of NOTCH1/2 by antagonizing DNMT1 protein stability, ultimately inducing the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Furthermore, the MAH, MIH, and PGH were tested for in vivo bone regeneration in rabbits with femur defects, and the results demonstrated that the MAH effectively stimulated bone regeneration. Taken together, these findings suggest that this magnetically and topographically anisotropic biomimetic hydrogel might be a promising candidate for application in the field of bone tissue regeneration.