RESUMEN
Van der Waals (vdW) ferromagnetic materials have emerged as a promising platform for the development of 2D spintronic devices. However, studies to date are restricted to vdW ferromagnetic materials with low Curie temperature (Tc) and small magnetic anisotropy. Here, a chemical vapor transport method is developed to synthesize a high-quality room-temperature ferromagnet, Fe3GaTe2 (c-Fe3GaTe2), which boasts a high Tc = 356 K and large perpendicular magnetic anisotropy. Due to the planar symmetry breaking, an unconventional room-temperature antisymmetric magnetoresistance (MR) is first observed in c-Fe3GaTe2 devices with step features, manifesting as three distinctive states of high, intermediate, and low resistance with the sweeping magnetic field. Moreover, the modulation of the antisymmetric MR is demonstrated by controlling the height of the surface steps. This work provides new routes to achieve magnetic random storage and logic devices by utilizing the room-temperature thickness-controlled antisymmetric MR and further design room-temperature 2D spintronic devices based on the vdW ferromagnet c-Fe3GaTe2.
RESUMEN
Transition metal phosphide (TMP) emerges as a promising electrocatalyst for overall water splitting (OWS). However, conventional TMP materials require exogenous metal ions to participate in coordination reactions, which usually suffer from active site blocking, pronounced intrinsic impedance, and inevitable catalyst shedding at high current density. Herein, a novel in-situ construction strategy has been developed to grow N-doped carbon (NC) enwrapped Co/CoP nanosheets directly onto Co foam (abbreviated as CoF) through a three-step transformation of Co to Co(OH)2 to Co-Metal-Organic Framework (Co-MOF) to Co/CoP/NC. In the entire preparation process, Co metal is only provided by the CoF substrate without external metal sources. Such in-situ construction yields tight contact at the interface of the heterogeneous catalyst, leading to much-reduced impedance and boundary vacancy, while the porous nitrogen-doped carbon backbone further endows the catalyst with the exposure of massive active sites, promotes mass transfer, and possesses high electrical conductivity. The Co/CoP/NC/CoF requires overpotentials of only 64 mV/263 mV@10 mA cm-2 and 414 mV/481 mV@400 mA cm-2 for both HER/OER in 1.0 M KOH, respectively. Remarkably, it reveals excellent OWS catalytic activity with a cell voltage of 1.56 V@10 mA cm-2 and 1.88 V@200 mA cm-2. This strategy of in-situ interface engineering transformation provides new ideas for direct device processing and construction of highly-efficient transition-metal-based OWS electrode materials.
RESUMEN
Time-varying quadratic programming (TV-QP) is widely used in artificial intelligence, robotics, and many other fields. To solve this important problem, a novel discrete error redefinition neural network (D-ERNN) is proposed. By redefining the error monitoring function and discretization, the proposed neural network is superior to some traditional neural networks in terms of convergence speed, robustness, and overshoot. Compared with the continuous ERNN, the proposed discrete neural network is more suitable for computer implementation. Unlike continuous neural networks, this article also analyzes and proves how to select the parameters and step size of the proposed neural networks to ensure the reliability of the network. Moreover, how to achieve the discretization of the ERNN is presented and discussed. The convergence of the proposed neural network without disturbance is proven, and bounded time-varying disturbances can be resisted in theory. Furthermore, the comparison results with other related neural networks show that the proposed D-ERNN has a faster convergence speed, better antidisturbance ability, and lower overshoot.
RESUMEN
The regulation of the multi-dimensional interface plays an important role in optimizing the electron transport and gas mass transfer during catalysis, which is conducive to promoting the electrocatalytic process. Herein, a self-supporting electrode has been developed with the multistage interface within 3D Ni2P@C nanospheres/nanoflowers arrays derived from metal-organic frameworks (MOFs) as template skeletons and precursors. The constructed nanosphere interface protrudes outward to optimize the contact with the electrolyte while the nanoflower lamellar connection promotes rapid electron transfer and exposes more active sites, and accelerates the gas diffusion with the abundant interspace channels. According to theoretical calculation, the synergistic effect between Ni2P and C is conducive to the optimal adsorption and desorption of H*, thus contributing to the improvement of catalytic kinetics. With the optimized growth times assembled onto nickel foam substrates, the Ni2P@C-12 h requires overpotentials of only 69 mV and 205 mV to drive the current density of 10 mA cm-2 towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. And it reveals an ultralow cell voltage of 1.55 V at 10 mA cm-2 to achieve overall water splitting (OWS). In addition, the stability of the Ni2P@C/NF electrocatalyst emerges as prominent long-term stability, which is attributed to the carbonaceous nanosphere anchors on the substrate to minimize the possibility of oxidation of the catalyst surface. This strategy of in situ growth of MOF-derived phosphates provides a general idea for interfacial engineering modification of OWS electrode materials.
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An ideal hair-care product can restore the hydrophobicity and neutralize the static electricity of hair. As an effective ingredient in hair-care products, silicone oil is difficult to form emulsions due to its hydrophobic and oleophobic properties. To overcome these issues, a new system with natural polysaccharide-based particles and cationic conditioning agent as efficient emulsifier for hair-care product has been designed. In this study, a facile emulsifier formed with cellulose nanocrystals (CNCs) and hexadecyltrimethylammonium chloride (CTAC) was prepared. Compared with commercial emulsifiers, the CNCs/CTAC complex showed significant synergetic effect in preparing and stabilizing silicone oil emulsion. The properties of the gained silicone oil emulsion, deposition of silicone oil onto hair and combing work of hair could be controlled depending on CTAC concentration. Considering the functional properties of CTAC, which can absorb onto the hair to neutralize negative charges, silicone oil emulsion stabilized by CNCs/CTAC complex would be applied to hair-care product.
RESUMEN
OBJECTIVE: Insulin-like grouth factor-1 (IGF-1) is polypetide hormone that has demonstrated effects on neural cells. Up to now, there is few reports about the relation between serum IGF-1 and brain damage in neonates with hyperbilirubinemia. This study explored the potential role of serum IGF-1 in neonatal hyperbilirubinemia. METHODS: Serum levels of IGF-1 were measured using ECLIA in 57 term neonates with hyperbilirubinemia and 25 normal term neonates. Meanwhile, total serum bilirubin (TSB), unconjugated bilirubin (USB) and serum albumin (ALB) contents were measured by the automatic biochemistry analyzer and the ratio of USB/ALB (B/A) was calculated. The hyperbilirubinemia group was classified into three subgroups based on serum TSB levels: mild (221-256 micromol/L), moderate (257-342 micromol/L) and severe (>342 micromol/L). Serum TSB levels in the 25 normal neonates were less than 85 micromol/L (control group). NBNA was performed on the day of serum sample collection. RESULTS: Serum IGF-1 levels in the mild, moderate and severe hyperbilirubinemia groups (39.38+/- 8.42, 30.77+/- 4.65 and 26.34+/- 2.05 ng/L, respectively) were obviously lower than those in the control group (50.16+/- 15.73 ng/L) (P< 0.01). There were significant differences among the three hyperbilirubinemia subgroups in serum IGF-1 levels (P< 0.01). Mean NBNA scores in the mild, moderate and severe hyperbilirubinemia groups (35.01+/- 2.26, 32.45+/- 2.74 and 26.77+/- 5.02, respectively) were significantly lower than those in the control group (38.24+/- 0.78) (P< 0.01). Significant differences in the NBNA scores were noted among the three hyperbilirubinemia subgroups (P< 0.01). Serum IGF-1 levels were positively correlated to NBNA scores (r=0.603, P< 0.01) and negatively correlated to the ratio of B/A (r=-0.483, P< 0.01). CONCLUSIONS: Serum IGF-1 levels decreased obviously in neonates with hyperbilirubinemia and correlated to the severity of disease. IGF-1 might be associated with bilirubin-induced brain damage.
