Phase change materials (PCMs) are key to the development of artificial intelligence technologies such as high‐density memories and neuromorphic computing, thanks to their ability for multi‐level data ...storage through stepwise resistive encoding. Individual resistance levels are realized by adjusting the crystalline and amorphous volume fraction of the memory cell. However, the amorphous phase exhibits a drift in resistance over time that has so far hindered the commercial implementation of multi‐level storage schemes. In this study, the underlying physical process of resistance drift with the goal of modeling is elucidated that will help minimize and potentially overcome drift in PCM memory devices. Clear evidence is provided that the resistance drift is dominated by glass dynamics. Resistivity convergence and drift inversion for the amorphous chalcogenide Ge15Te85 and the PCM Ge3Sb6Te5 are experimentally demonstrated and these changes are successfully predicted with a glass dynamics model. This new insight into the resistance drift process provides tools for the development of advanced PCM devices.
Resistance drift of amorphous phase‐change materials (PCMs) is usually explained by structural relaxation. It manifests itself in aging, stabilization, and rejuvenation. It is found that these processes lead to resistance drift, convergence, and drift inversion. The resistance evolution is described accurately by conventional glass dynamics. These findings will help to realize drift‐free multi‐level PCM devices essential for brain‐inspired neuromorphic networks and artificial intelligence.
In the era of information explosion, high‐security and high‐capacity data storage technology attracts more and more attention. Physically transient electronics, a form of electronics that can ...physically disappear with precisely controlled degradation behaviors, paves the way for secure data storage. Herein, the authors report a silk‐based hierarchically encoded data storage device (HEDSD) with controlled transiency. The HEDSD can store electronic, photonic, and optical information simultaneously by synergistically integrating a resistive switching memory (ReRAM), a terahertz metamaterial device, and a diffractive optical element, respectively. These three data storage units have shared materials and structures but diverse encoding mechanisms, which increases the degree of complexity and capacity of stored information. Silk plays an important role as a building material in the HEDSD thanks to its excellent mechanical, optical, and electrical properties and controlled transiency as a naturally extracted protein. By controlling the degradation rate of storage units of the silk‐based HEDSD, different degradation modes of the HEDSD, and multilevel information encryption/decryption have been realized. Compared with the conventional memory devices, as‐reported silk‐based HEDSD can store multilevel complex information and realize multilevel information encryption and decryption, which is highly desirable to fulfill the future demands of secure memory systems and implantable storage devices.
A hierarchically encoded data storage device consisting of resistive switching memory, electromagnetic (EM) metamaterial, and diffractive optical element is reported in this paper. The storage devices can be used to store hybrid information including electronic information, EM information, and optical information. It also exhibits controllable degradation manners in vitro and in vivo, which expands the applications in bio‐implantable electronics.
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•MnSbTiOx-0.2 catalyst shows higher SCR activity and better SO2 resistance than MnTiOx catalyst.•The addition of Sb on MnTiOx catalyst could improve the adsorption of NH3 and NOx ...species.•The SCR reaction over MnSbTiOx-0.2 catalyst is mainly accelerated via L-H route.
Sb was used as the additive to enhance the NH3-SCR performance of MnTiOx catalyst. Experimental results revealed that MnSbTiOx-0.2 demonstrated outstanding NH3-SCR activity in a wide temperature window (100–400 ℃) and high resistance to SO2. Characterization results indicated the introduction of Sb into MnTiOx catalyst could improve the dispersity of active species and generate more surface acid sites, Mn4+ and surface adsorbed oxygen species. In situ DRIFT spectra proved that the presence of Sb in MnSbTiOx-0.2 catalyst could form new Brønsted acid sites, along with the increased surface Lewis acidity. The improved adsorption of NH3 and NOx species over MnSbTiOx-0.2 catalyst had a stimulating effect on the NH3-SCR reaction over it through Langmuir−Hinshelwood (L-H) route. Moreover, Sb species in MnSbTiOx-0.2 could improve the reactivities of ad-NH3 and ad-NOx species in SCR reaction. All these factors contributed to the excellent performance of MnSbTiOx-0.2 catalyst.
The epoxy intermediates with three hydroxyl groups were synthesized from 2-aminoethanol (ETA) with ethylene glycol diglycidyl ether (EGDE) or resorcinol diglycidyl ether (RDGE), followed by the ...neutralization of the inherent tertiary amine groups. The intermediate was then reacted with isophorone diisocyanate (IPDI) to produce polyurethane prepolymer, which was further chain-extended and modified by polyethylene glycol (PEG-1000) and polyethylene glycol monomethyl ether (MPEG-1200), respectively. Finally, methyl ethyl ketone oxime (MEKO) was used to block the residual isocyanate (NCO) group, leading to the achievement of the waterborne polymeric crosslinkers containing blocked NCO moieties and active epoxy groups. The structure of the crosslinkers was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (
1
H-NMR). TG and DTG profiles show that both crosslinkers can quickly crosslink and cure the resin at temperatures above 96 °C. The mechanical properties of the cured films obtained by applying crosslinkers to electrophoretic coatings were also studied. The results show that the coating prepared by the crosslinker of the RDGE system has the best adhesion and can reach a maximum of 0.66 MPa.
In this work, a series of BaSrGd4O8:xBi3+ blue phosphors was synthesized employing the high-temperature solid-state method. Phase purity of the samples was verified by X-ray diffraction and Rietveld ...refinement. Time-resolved photoluminescence spectra revealed the existence of two distinct Bi sites. Subsequent optimization of dopant types and doping levels in the batch led to an almost twofold increase in quantum efficiency. The introduction of Eu3+ into the phosphors facilitated the construction of an energy transfer pathway. As the concentration of Eu3+ was increased, the emission color changed from blue to purple and finally to red. In addition, the thermal stability and potential applications of the phosphors were extensively investigated. Finally, two WLED devices were successfully fabricated with color rendering indices of 96.27 and 92.18, and correlated color temperatures of 5198 and 2475 K. This underscores the prospective application of these phosphors in the field of high-quality warm WLEDs.
The shift to an environmentally friendly material economy requires renewable resource exploration. This shift may depend on lignin valorization. Lignin is an aromatic polymer that makes up one-third ...of total lingo-cellulosic biomass and is separated into large amounts for biofuel and paper manufacture. This renewable polymer is readily available at a very low cost as nearly all the lignin that is produced each year (90–100 million tons) is simply burned as a low-value fuel. Lignin offers potential qualities for many applications, and yet it is underutilized. This Perspective highlights lignin-based material prospects and problems in food packaging, antimicrobial, and agricultural applications. The first half will discuss the present and future studies on exploiting lignin as an addition to improve food packaging’s mechanical, gas, UV, bioactive molecules, polyphenols, and antioxidant qualities. Second, lignin’s antibacterial activity against bacteria, fungi, and viruses will be discussed. In conclusion, lignin agriculture will be discussed in the food industries.
The organosilicon intermediate containing hydrophilic tertiary amines was synthesized from N-Methylmonoethanolamine (MEA) and (3-glycidyloxypropyl) trimethoxy silane (GPTMS), followed by ...neutralization with acetic acid (Ac). Meanwhile, a polyurethane (PU) prepolymer was prepared by sequentially polymerizing hexamethylene diisocyanate trimer (HT-100) with polyethylene glycol (PEG-600) and methoxy polyethylene glycol (MPEG), and then chain extended by the intermediate. Ultimately, methyl ethyl ketone oxime (MEKO) was selected to block the remaining NCO group, forming a branched polyisocyanate crosslinker. Subsequently, a linear polyisocyanate crosslinker was prepared in the same system by polymerizing hexamethylene diisocyanate (HDI) with the intermediate. Consequently, an organosilicon-modified waterborne blocked polyisocyanate crosslinker with a semi-interpenetrating network structure was obtained and further processed through hydrolysis to obtain the corresponding crosslinker containing silanol groups. The structure and thermal properties of the crosslinkers were analyzed using 1H NMR, FT-IR, TG, and DTG. Furthermore, the comprehensive mechanical properties of the cured films were investigated. The results indicate that the crosslinker system containing silanol groups exhibits superior performance. When the films' maximum adhesion and the wiping resistance were optimized at 1.97 MPa and 72 times, respectively, the impact resistance still maintained above 85 cm.
•The introduction of organosilicon into the polyisocyanate crosslinker structure can realize multiple crosslinking for resins•The crosslinker has a semi-interpenetrating network structure and exhibits excellent mechanical properties in applications•Organosilicon-modified waterborne blocked polyisocyanate might have good application prospects in waterborne coatings
Na2MgScF7 (NMSF) was experimentally obtained for the first time by combining hydrothermal and high-temperature solid-state reactions. X-ray powder diffraction (XRD) combined with Rietveld refinement ...confirms that NMSF is crystallized in the space group Imma with the cell parameters a = 10.40860(18), b = 7.32804(12) and c = 7.52879(11) Å, α = β = γ = 90° and V = 574.256(24) Å3. Through doping with Tb3+ or Eu3+ ions, downshifting yellow-green or red emission could be achieved in NMSF-based phosphors, respectively. Upconversion emission could also be designed by doping with Yb3+–Er3+, Yb3+–Tm3+, Yb3+–Ho3+ or Er3+. Moreover, the NMSF:Er3+ phosphor exhibited green upconversion emission upon excitation at 980 nm, and it exhibited red emission upon excitation at 1532 nm. Finally, recognizable patterns were obtained under excitation at 254, 365 and 980 nm, indicating that the as-prepared phosphors can be applied to multicolor anti-counterfeiting. Moreover, our synthesis strategy opens up new avenues for the synthesis of novel fluorides.
Trimethylamine N-oxide (TMAO) is closely related to cardiovascular diseases, particularly heart failure (HF). Recent studies shows that 3,3-dimethyl-1-butanol (DMB) can reduce plasma TMAO levels. ...However, the role of DMB in overload-induced HF is not well understood. In this research study, we explored the effects and the underlying mechanisms of DMB in overload-induced HF. Aortic banding (AB) surgery was performed in C57BL6/J mice to induce HF, and a subset group of mice underwent a sham operation. After surgery, the mice were fed with a normal diet and given water supplemented with or without 1% DMB for 6 weeks. Cardiac function, plasma TMAO level, cardiac hypertrophy and fibrosis, expression of inflammatory, electrophysiological studies and signaling pathway were analyzed at the sixth week after AB surgery. DMB reduced TMAO levels in overload-induced HF mice. Adverse cardiac structural remodeling, such as cardiac hypertrophy, fibrosis and inflammation, was elevated in overload-induced HF mice. Susceptibility to ventricular arrhythmia also significantly increased in overload-induced HF mice. However, these changes were prevented by DMB treatment. DMB attenuated all of these changes by reducing plasma TMAO levels, hence negatively inhibiting the p65 NF-κB signaling pathway and TGF-β1/Smad3 signaling pathway. DMB plays an important role in attenuating the development of cardiac structural remodeling and electrical remodeling in overload-induced HF mice. This may be attributed to the p65 NF-κB signaling pathway and TGF-β1/Smad3 signaling pathway inhibition.
Water security is an important component of regional security and sustainable development and it significantly affects regional development strategies. Flood security, water resource security, and ...water environment security are the basic elements of a water security system. These elements exhibit dynamic and complex characteristics. System dynamics (SD) is a qualitative and quantitative simulation and analysis method for system integration. SD is applicable to complex system research and has achieved significant results in water security system research. This study initially collected literature on water security research and application in recent years, and then verified the progress and deficiencies in current research. Our research on water security focuses on managing and predicating a single subsystem. Our research on flood control and disaster mitigation focuses on managing and forecasting floods. Our research on water resource security focuses on water resource management, carrying capacity, and planning, as well as on sustainable water utilization. Finally, our research on water environment security includes water quality management, water pollution control, early warning systems, and water ecology. The SD method can properly solve the complicated relations in a water security system but exhibits limitations in the following aspects: research on large systems; influence of social environment changes; uncertainties in water security; and the methods, means, and influence of natural environment changes on water security.
