Optical characteristics of luminescent materials, including emission color (wavelength), lifetime, and excitation mode, play crucial roles in data communication and information security. Conventional ...luminescent materials generally display unicolor, unitemporal, and unimodal (occasionally bimodal) emission, resulting in low‐level readout and decoding. The development of multicolor, multitemporal, and multimodal luminescence in a single material has long been considered to be a significant challenge. In this study, for the first time, the superior integration of colorful (red–orange–yellow–green), bitemporal (fluorescent and delayed), and four‐modal (thermo‐/mechano‐motivated and upconverted/downshifted) emissions in a particular piezoelectric particle via optical multiplexing of dual‐lanthanide dopants is demonstrated. The as‐prepared versatile NaNbO3:Pr3+,Er3+ luminescent microparticles shown are particularly suitable for embedding into polymer films to achieve waterproof, flexible/wearable and highly stretchable features, and synchronously to provide multidimensional codes that can be visually read‐out using simple and commonly available tools (including the LED of a smartphone, pen writing, cooling–heating stimuli, and ultraviolet/near‐infrared lamps). These findings offer unique insight for designing highly integrated stimuli‐responsive luminophors and smart devices toward a wide variety of applications, particularly advanced anticounterfeiting technology.
Thermo‐mechano‐opto‐responsive bitemporal (fluorescent and delayed) colorful (red–orange–yellow–green) luminescence is designed and achieved through optical multiplexing of dual‐lanthanides of Pr3+ and Er3+ in NaNbO3 piezoelectric microparticles. The smart materials are well‐embedded into polymer elastomers to show waterproof, flexible/wearable and highly‐stretchable features, and provide multidimensional codes that enable visual readout using commonly available tools (e.g., smartphone flashlight, pen writing, and cooling‐heating stimuli).
Visually readable codes play a crucial role in anticounterfeiting measures. However, current coding approaches do not enable time‐dependent codes to be visually read, adjusted, and differentiated in ...bright and dark fields. Here, using a combined strategy of piezoelectric lattice selection, oxygen vacancy engineering, and activator doping, a lanthanide ion‐doped titanate is developed that integrates mechano‐, thermo‐, and photo‐responsive color change (>18 h for bright field), persistent luminescence (>6 h for dark field), and stimulus‐triggered multimodal luminescence. The feasibility of optical encoding, visual displaying, and stimulus‐responsive encrypting of time‐dependent, dual‐field information by using the developed material is demonstrated. In particular, the differentiated display of dual‐field modes is achieved by combining mechanostimulated abolition of only the persistent luminescence and thermo‐ and photostimulated reversal of both the color change and persistent luminescence. The results provide new insights for designing advanced materials and encryption technologies for photonic displays, information security, and intelligent anticounterfeiting.
The encoding, displaying, and encrypting of information in bright and dark fields are demonstrated via a newly designed versatile material that integrates bright‐field color change, dark‐field persistent luminescence, and stimuli‐responsive multiluminescence. Differential encryption of the dual‐field patterns is creatively modulated by combining the mechanostimulated loss of only the dark‐field patterns and thermo‐ and photostimulated dual abolition of the dual‐field patterns.
Organic nitrates are broadly applied as pharmaceuticals (acting as efficient nitric oxide donor), energetic materials, building blocks in organic synthesis, etc. However, practical and direct methods ...to access organic nitrates efficiently are still rare, mainly due to the lack of powerful nitrooxylating reagents. Herein, we report bench‐stable and highly reactive noncyclic hypervalent iodine nitrooxylating reagents, oxybis(aryl‐λ3‐iodanediyl) dinitrates (OAIDNs, 2), which are prepared just by using aryliodine diacetate and HNO3. The reagents are used to achieve a mild and operationally simple protocol to access diverse organic nitrates. By employing of 2, zinc‐catalyzed regioselective nitrooxylation of cyclopropyl silyl ethers is realized efficiently to access the corresponding β‐nitrooxy ketones with high functional‐group tolerance. Moreover, a series of direct and catalyst‐free nitrooxylations of enolizable C−H bonds are carried out smoothly to afford the desired organic nitrates within minutes by just mixing the substrates with 2 in dichloromethane.
A bench‐stable and highly reactive noncyclic hypervalent iodine nitrooxylating reagent is prepared from aryliodine diacetate and HNO3. This reagent facilitates the zinc‐catalyzed regioselective nitrooxylation of cyclopropyl silyl ethers with broad scope, and also can be used in the nitrooxylation of various enolizable C−H bonds.
The engineering of intermolecular interaction is challenging but critical for magnetically switchable molecules. Here, we prepared two cyanide‐bridged Fe4Co4 cube complexes via the alkynyl‐ and ...alcohol‐functionalized trispyrazoyl capping ligands. The alkynyl‐functionalized complex 1 exhibited a thermally‐induced incomplete metal‐to‐metal electron transfer (MMET) behaviour at around 220 K, while the mixed alkynyl/alcohol‐functionalized cube of 2 showed a complete and abrupt MMET behaviour at 232 K. Remarkably, both compounds showed a long‐lived photo‐induced metastable state up to 200 K. The crystallographic study demonstrated that the incomplete transition of 1 was likely due to the possible elastic frustration originating from the competition between the anion‐propagated elastic interactions and inter‐cluster alkynyl‐alkynyl & CH‐alkynyl interactions, whereas the latter are eliminated in 2 as a result of the partial substitution by the alcohol‐functionalized ligand. Additionally, the introduction of chemically distinguishable cobalt centers within the cube unit of 2 did not lead to a two‐step but a one‐step transition, possibly because of the strong ferroelastic intramolecular interaction through the cyanide bridges.
Two cyanide‐bridged Fe4Co4 cubes were prepared via a mixed‐ligand approach. The molecular origins of their distinct (incomplete vs. complete) metal‐to‐metal electron transfer (MMET) properties were identified as the presence and absence of the inter‐cluster alkynyl‐alkynyl and CH/π interactions. These compete with the cluster‐anion interactions, resulting in the underlying elastic frustration and stopping the complete spin transition in 1.
There is an urgent need for animal models to study SARS-CoV-2 pathogenicity. Here, we generate and characterize a novel mouse-adapted SARS-CoV-2 strain, MASCp36, that causes severe respiratory ...symptoms, and mortality. Our model exhibits age- and gender-related mortality akin to severe COVID-19. Deep sequencing identified three amino acid substitutions, N501Y, Q493H, and K417N, at the receptor binding domain (RBD) of MASCp36, during in vivo passaging. All three RBD mutations significantly enhance binding affinity to its endogenous receptor, ACE2. Cryo-electron microscopy analysis of human ACE2 (hACE2), or mouse ACE2 (mACE2), in complex with the RBD of MASCp36, at 3.1 to 3.7 Å resolution, reveals the molecular basis for the receptor-binding switch. N501Y and Q493H enhance the binding affinity to hACE2, whereas triple mutations at N501Y/Q493H/K417N decrease affinity and reduce infectivity of MASCp36. Our study provides a platform for studying SARS-CoV-2 pathogenesis, and unveils the molecular mechanism for its rapid adaptation and evolution.
This study focuses on the additive manufacturing technique of selective laser melting (SLM) to produce Ti-6Al-4V-Zn titanium alloy. The addition of zinc at 0.3 wt.% was investigated to improve the ...strength and ductility of SLM Ti-6Al-4V alloys. The microstructure and mechanical properties were analyzed using different vacuum heat treatment processes, with the 800-4-FC specimen exhibiting the most favorable overall mechanical properties. Additionally, zinc serves as a stabilizing element for the β phase, enhancing the resistance to particle erosion and corrosion impedance of Ti-6Al-4V-Zn alloy. Furthermore, the incorporation of trace amounts of Zn imparts improved impact toughness and stabilized high-temperature tensile mechanical properties to SLM Ti-6Al-4V-Zn alloy. The data obtained serve as valuable references for the application of SLM-64Ti.
We study the mixed state entanglement in a holographic axion model. We find that the holographic entanglement entropy (HEE), mutual information (MI) and entanglement of purification (EoP) exhibit ...very distinct behaviors with system parameters. The HEE exhibits universal monotonic behavior with system parameters, while the behaviors of MI and EoP relate to the specific system parameters and configurations. We find that MI and EoP can characterize mixed state entanglement better than HEE since they are less affected by thermal effects. Specifically, the MI partly cancels out the thermal entropy contribution, while the holographic EoP is not dictated by the thermal entropy in any situation. Moreover, we argue that EoP is more suitable for describing mixed state entanglement than MI. Because the MI of large configurations are still dictated by the thermal entropy, while the EoP will never be controlled only by the thermal effects.
In this project, for the first time we successfully develop an approach to fabricate a novel core-shell structure of CoPBA@Ni(OH)2, in which Ni(OH)2 nano-sheets covered on the surface of CoPBA ...nanocubes through in-situ etching and growing processes, furthermore, being sulfurized into its hierarchical porous structure of CoS2@NiS2. The CoS2@NiS2 composite as a high-performance surpercapacitor electrode has been demonstrated. It exhibits very high specific capacitance value of 1731.2 F g−1 at 1 A g−1, excellent rate performance of 83.5% retention at 10 A g−1 and cycle performance with 87.1% retention after 5000 cycles together with distinguished coulombic efficiency of around 100%. Kinetic analysis and electrochemical impedance spectroscopy (EIS) results reveal the related mechanism. Herein, prussian blue analogue (PBA) as central core with cubic skeleton displays some great advantages, (1) it can provide more efficient electron conduction path to reduce the resistance of composite, (2) it can effectively prevent the agglomeration of electroactive Ni(OH)2 as well as sulfurized CoS2@NiS2 composite, (3) it can reduce ion diffusion pathway with mesoporous structure and enlarged surface area, greatly improving cycle stability. Such synthetic strategy opens up a new avenue for the effective construction of core-shell structure based on PBA basement for promising supercapacitor application.
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•A novel core-shell structure of CoPBA@Ni(OH)2 was successfully fabricated.•CoPBA@Ni(OH)2 was sulfurized to CoS2@NiS2 with hierarchical porous structure.•CoS2@NiS2 as an excellent high-performance surpercapacitor has been demonstrated.•It exhibits high specific capacitance, rate performance, and cycling stability.•It was aso fabricated into high-performance asymmetric supercapacitor.
Metal-organic frameworks (MOFs) as a promising electrode materials have received increasing attention in supercapacitors. The construction of nanoscale MOF materials was considered as an effective ...strategy to enhance electrochemical performances. In this work, CuMOF crystal and NiMOF crystal are synthesized by selecting redox-active organic linker and metal centers. Then, an in-situ solvothermal method is developed and applied successfully to prepare their nano materials, named as nano-CuMOF 1–10 and nano-NiMOF 1–10, under a facile and mild condition. In particular, it is found that various morphology and nano sizes for these nano-CuMOFs and nano-NiMOFs can be effectively controlled based on solvent effect and surfactant effect. All structures of as-synthesized nano materials are demonstrated by XRD and FT-IR results, which are consistent with the ones of their crystals. More importantly, electrochemical properties can be greatly enhanced from bulk crystals of CuMOF and NiMOF to nano-CuMOF and nano-NiMOF materials. Their nano materials exhibit excellent supercapacitor performance. Among of them, nano-NiMOF 3 as supercapacitor electrode shows the best specific capacitance of 1024.44 F g−1 at a current densities of 1 A g−1 and maintains very good cycling stability. Its capacitance retention of 49.07% can be observed after 5000 cycles at a current density of 5 A g−1. In addition, a high-performance asymmetric supercapacitor (ASC) was fabricated by using nano-NiMOF 3 and activated carbon as two electrodes. A specific capacitance of 38.65 F g−1 was obtained at a current density of 0.5 A g−1, and 109% capacity of the initial capacitance at 3 A g−1 after 5000 cycles can be observed.
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•Pristine MOF and their nano materials can be successfully synthesized.•Morphologies for nano-CuMOFs/nano-NiMOFs can be effectively controlled.•Their nano materials exhibit excellent supercapacitor performance.•High-performance asymmetric supercapacitor (ASC) was also fabricated.
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