Near‐infrared (NIR) organic solid‐state lasers play an essential role in applications ranging from laser communication to infrared night vision, but progress in this area is restricted by the lack of ...effective excited‐state gain processes. Herein, we originally proposed and demonstrated the cascaded occurrence of excited‐state intramolecular proton transfer for constructing the completely new energy‐level systems. Cascading by the first ultrafast proton transfer of <430 fs and the subsequent irreversible second proton transfer of ca. 1.6 ps, the stepwise proton transfer process favors the true six‐level photophysical cycle, which supports efficient population inversion and thus NIR single‐mode lasing at 854 nm. This work realizes longest wavelength beyond 850 nm of organic single‐crystal lasing to date and originally exploits the cascaded excited‐state molecular proton transfer energy‐level systems for organic solid‐state lasers.
Six‐level energy systems are constructed through the cascaded occurrence of excited‐state intramolecular proton transfer consisting of a first ultrafast proton transfer of <430 fs and a following dominant and irreversible proton transfer of ca. 1.6 ps, which support the NIR single‐mode lasing at 854 nm for exploiting energy‐level systems of OSSLs, especially at the NIR region from 780 to 2500 nm.
Motivated by the concept of energy-optimized air/space vehicles, the design of more-electric and all-electric vehicles has become increasingly popular. With the advance of micro-electro-mechanical ...systems, on-board electronic/electrical devices become more integrated and miniaturized. It means that these highly-advanced devices should rely on a high heat-flux dissipation method to maintain an effective and safe operation. Spray cooling, universally recognized as the next-generation cooling scheme, has been extensively utilized in the thermal protection of the ground-based electric/electronic equipment. In contrast, the aerospace-oriented spray cooling (AOSC) application is extremely rare. It can be attributed to the fact that the research into the space/air-oriented spray cooling technologies is still in its infancy, which leads to a lack in the knowledge of alternations of flow patterns and heat transfer behaviors caused by the complicated space or high-altitude space. This paper presents a comprehensive review of the up-to-date published articles on AOSC and divides these published articles into four categories: 1) investigation into the effect of gravity on the cooling performance; 2) investigation into the effect of environmental pressure on the cooling performance; 3) study of the effect of acceleration and vibration on the cooling performance; 4) investigation of the aerospace spray cooling system. Additionally, comments, perspectives, and orientations are provided, in which several promising contributions are highlighted. This paper aims to promote the practical application of the AOSC system which could facilitate the development of the energy-optimized green air/space vehicle.
•A review of aerospace-oriented spray cooling technology is performed.•Gravity plays a significant role in the flow pattern and heat & mass transfer.•A heat transfer enhancement can be gained by flash Boiling/evaporation.•Gravity-immune spray cooling systems promote its practical aerospace application.•Affordable ground-based research method for aerospace application is imperative.
Resurfacing perovskite nanocrystals (NCs) with tight‐binding and conductive ligands to resolve the dynamic ligands—surface interaction is the fundamental issue for their applications in perovskite ...light‐emitting diodes (PeLEDs). Although various types of surface ligands have been proposed, these ligands either exhibit weak Lewis acid/base interactions or need high polar solvents for dissolution and passivation, resulting in a compromise in the efficiency and stability of PeLEDs. Herein, we report a chemically reactive agent (Iodotrimethylsilane, TMIS) to address the trade‐off among conductivity, solubility and passivation using all‐inorganic CsPbI3 NCs. The liquid TMIS ensures good solubility in non‐polar solvents and reacts with oleate ligands and produces in situ HI for surface etching and passivation, enabling strong‐binding ligands on the NCs surface. We report, as a result, red PeLEDs with an external quantum efficiency (EQE) of ≈23 %, which is 11.2‐fold higher than the control, and is among the highest CsPbI3 PeLEDs. We further demonstrate the universality of this ligand strategy in the pure bromide system (CsPbBr3), and report EQE of ≈20 % at 640, 652, and 664 nm. This represents the first demonstration of a chemically reactive ligand strategy that applies to different systems and works effectively in red PeLEDs spanning emission from pure‐red to deep‐red.
A solution‐phase ligand exchange strategy is used to resurface perovskite nanocrystal surfaces with a chemically active, short and conductive ligand, Iodotrimethylsilane (TMIS), which also functions as a surface passivant. Excellent conductivity and photostability allowed us to fabricate compact, high‐mobility and trap‐free perovskite NC films with high PLQY (>90%). As a result, we achieve CsPbI3 NC‐based PeLEDs with an EQE of ~23%.
Perovskite light‐emitting diodes (LEDs) emitting in the pure‐red range of 630–640 nm show promise in meeting the requirement of the Rec.2100 standard for high‐resolution displays. However, the ...high‐performing LEDs (external quantum efficiency, EQE >20%) in the pure‐red range suffer from half‐life time (luminance drop to 50% of the initial luminance) of <1.6 h, resulting from the injection/transportation barrier and surface‐defects–induced charge carrier quenching. Herein, a bi‐ligand synergy strategy is developed to address the T50 issue: the introduction of iodide‐rich ligands with different chain length increases the vacancy formation energy of halogen ions and enhances the exciton binding energy, resulting in a high photoluminescence quantum yield of over 92%. The treated CsPbBrx/I3−x films exhibit 34‐fold improved material stability related to the control at continuous aging at 100 °C. As a result, pure‐red LEDs with CIE coordinates of (0.698, 0.301) approaching the Rec.2100 standard are reported. These pure‐red LEDs exhibit a low turn‐on voltage of 1.8 V, which is the lowest among reported pure‐red perovskite LEDs, and even 0.15 V lower than the optical bandgap energy (1.95 eV); and a maximum EQE of ≈21% with fourfold enhanced T50 relative to the best previous pure‐red perovskite LEDs.
The iodide‐rich ligands in the bi‐ligand synergy strategy increase the vacancy formation energy of halogen ions, resulting in a high photoluminescence quantum yield of over 92%. The light‐emitting diodes exhibit a maximum external quantum efficiency of ≈21% with fourfold enhanced T50 relative to the best previous pure‐red perovskite light‐emitting diodes.
Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a poor inducer of innate antiviral immunity, and the underlying mechanism still needs further investigation. Here, we reported that ...SARS‐CoV‐2 NSP7 inhibited the production of type I and III interferons (IFNs) by targeting the RIG‐I/MDA5, Toll‐like receptor (TLR3)‐TRIF, and cGAS‐STING signaling pathways. SARS‐CoV‐2 NSP7 suppressed the expression of IFNs and IFN‐stimulated genes induced by poly (I:C) transfection and infection with Sendai virus or SARS‐CoV‐2 virus‐like particles. NSP7 impaired type I and III IFN production activated by components of the cytosolic dsRNA‐sensing pathway, including RIG‐I, MDA5, and MAVS, but not TBK1, IKKε, and IRF3‐5D, an active form of IRF3. In addition, NSP7 also suppressed TRIF‐ and STING‐induced IFN responses. Mechanistically, NSP7 associated with RIG‐I and MDA5 prevented the formation of the RIG‐I/MDA5−MAVS signalosome and interacted with TRIF and STING to inhibit TRIF‐TBK1 and STING‐TBK1 complex formation, thus reducing the subsequent IRF3 phosphorylation and nuclear translocation that are essential for IFN induction. In addition, ectopic expression of NSP7 impeded innate immune activation and facilitated virus replication. Taken together, SARS‐CoV‐2 NSP7 dampens type I and III IFN responses via disruption of the signal transduction of the RIG‐I/MDA5−MAVS, TLR3‐TRIF, and cGAS‐STING signaling pathways, thus providing novel insights into the interactions between SARS‐CoV‐2 and innate antiviral immunity.
Hybrid CO2 electroreduction (HCER) is recognized as an important strategy to improve the total value of redox products and energy conversion efficiency. In this work, a coordination catalyst model ...system (Ni8‐TET with active oxidation sites, Ni‐TPP with active reduction sites and PCN‐601 with redox‐active sites) for HCER was established for the first time. Especially, PCN‐601 can complete both anodic methanol oxidation and cathodic CO2 reduction with FEHCOOH and FECO over 90 %. The performance can be further improved with light irradiation (FE nearly 100 %). DFT calculations reveal that the transfer of electrons from NiII8 clusters to metalloporphyrins under electric fields results in the raised oxidizability of Ni8 clusters and the raised reducibility of metalloporphyrin, which then improves the electrocatalytic performance. This work serves as a well‐defined model system and puts forward a new design idea for establishing efficient catalysts for hybrid CO2 electroreduction.
The transfer of electrons from electron‐rich metal clusters (oxidation active sites) to electron‐deficient metalloporphyrins (reduction active sites) leads to stronger oxidizability of Ni8 clusters and stronger reducibility of metalloporphyrin. The enhanced oxidizability of Ni8 and reducibility of metalloporphyrin, therefore, result in improved methanol electrooxidation and CO2 electroreduction with the bifunctional crystalline coordination catalyst.
Porous heterostructured electrocatalysts with multifunctionality and synergistic effect have much benefit for efficient electrocatalytic CO2 reduction reaction (CO2RR), yet it still remains a ...daunting challenge to explore heterostructures based on covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) in this field. Here, a series of honeycomb‐like porous crystalline hetero‐electrocatalysts (MCH‐X, X = 1–4, X stands for the numbered sample obtained from different MOF doses in the synthesis of the MCH) are synthesized, and these are successfully applied in electrocatalytic CO2RR. The specially designed heterostructures with integrated porous MOF‐template and ultrathin COF‐coating enable efficient CO2 adsorption/activation and conversion into CH4. The best of them, MCH‐3, shows greatly inhibited H2 evolution, excellent current density (−398.1 mA cm−2), and superior FECH4${\rm{F}}{{\rm{E}}_{{\rm{C}}{{\rm{H}}_4}}}$ (76.7%) to the physical mixture (38.0%), the MOF@COF without the honeycomb‐like morphology (47.7%), and the bare COF (37.5%) and MOF (15.9%) at −1.0 V. Based on the density functional theory calculations and various characterizations, the vital roles of the MOF in facilitating CO2 adsorption/activation, stabilizing intermediates, and conquering the energy barrier of rate‐determining step are intensively studied.
A series of honeycomb‐like metal–organic framework (MOF)@covalent organic framework (COF) heterostructures with integrated porous MOF template and ultrathin COF coating are synthesized and successfully applied in efficient CO2 electroreduction to CH4.
Integrating host and HBV characteristics, this study aimed to develop models for predicting long‐term cirrhosis and hepatocellular carcinoma (HCC) risk in chronic hepatitis B virus (HBV) patients. ...This analysis included hepatitis B surface antigen (HBsAg)‐seropositive and anti‐HCV‐seronegative participants from the Risk Evaluation of Viral Load Elevation and Associated Liver Disease/Cancer in HBV (R.E.V.E.A.L.‐HBV) cohort. Newly developed cirrhosis and HCC were ascertained through regular follow‐up ultrasonography, computerized linkage with national health databases, and medical chart reviews. Two‐thirds of the participants were allocated for risk model derivation and another one‐third for model validation. The risk prediction model included age, gender, HBV e antigen (HBeAg) serostatus, serum levels of HBV DNA, and alanine aminotransferase (ALT), quantitative serum HBsAg levels, and HBV genotypes. Additionally, the family history was included in the prediction model for HCC. Cox's proportional hazards regression coefficients for cirrhosis and HCC predictors were converted into risk scores. The areas under receiver operating curve (AUROCs) were used to evaluate the performance of risk models. Elder age, male, HBeAg, genotype C, and increasing levels of ALT, HBV DNA, and HBsAg were all significantly associated with an increased risk of cirrhosis and HCC. The risk scores estimated from the derivation set could accurately categorize participants with low, medium, and high cirrhosis and HCC risk in the validation set (P < 0.001). The AUROCs for predicting 3‐year, 5‐year, and 10‐year cirrhosis risk ranged 0.83‐0.86 and 0.79‐0.82 for the derivation and validation sets, respectively. The AUROC for predicting 5‐year, 10‐year, 15‐year risk of HCC ranged 0.86‐0.89 and 0.84‐0.87 in the derivation and validation sets, respectively. Conclusion: The risk prediction models of cirrhosis and HCC by integrating host and HBV profiles have excellent prediction accuracy and discriminatory ability. They may be used for clinical management of chronic hepatitis B patients. (Hepatology 2013;58:546‐554)
SARS‐CoV‐2 has developed a variety of approaches to counteract host innate antiviral immunity to facilitate its infection, replication and pathogenesis, but the molecular mechanisms that it employs ...are still not been fully understood. Here, we found that SARS‐CoV‐2 NSP8 inhibited the production of type I and III interferons (IFNs) by acting on RIG‐I/MDA5 and the signaling molecules TRIF and STING. Overexpression of NSP8 downregulated the expression of type I and III IFNs stimulated by poly (I:C) transfection and infection with SeV and SARS‐CoV‐2. In addition, NSP8 impaired IFN expression triggered by overexpression of the signaling molecules RIG‐I, MDA5, and MAVS, instead of TBK1 and IRF3‐5D, an active form of IRF3. From a mechanistic view, NSP8 interacts with RIG‐I and MDA5, and thereby prevents the assembly of the RIG‐I/MDA5‐MAVS signalosome, resulting in the impaired phosphorylation and nuclear translocation of IRF3. NSP8 also suppressed the TRIF‐ and STING‐ induced IFN expression by directly interacting with them. Moreover, ectopic expression of NSP8 promoted virus replications. Taken together, SARS‐CoV‐2 NSP8 suppresses type I and III IFN responses by disturbing the RIG‐I/MDA5−MAVS complex formation and targeting TRIF and STING signaling transduction. These results provide new insights into the pathogenesis of COVID‐19.
Strategy that can design powerful photothermal‐catalysts to achieve photothermal‐effect assisted coupling‐catalysis is much desired for the improvement of energy conversion efficiency and redox ...product value in CO2 electroreduction system. Herein, a kind of bifunctional viologen‐containing covalent organic framework (Ni‐2CBpy2+‐COF) has been prepared and successfully applied in photothermal‐assisted co‐electrolysis of CO2 and methanol. Specifically, the FECO (cathode) and FEHCOOH (anode) for Ni‐2CBpy2+‐COF can reach up to ≈100 % at 1.9 V with ≈31.5 % saved overall electricity‐consumption when the anodic oxygen evolution reaction (OER) is replaced by methanol oxidation. The superior performance could be attributed to the cyclic diquats in Ni‐2CBpy2+‐COF that enhance the photothermal effect (ΔT=49.1 °C) to accelerate faster charge transfer between catalyst and immediate species as well as higher selectivity towards desired products as revealed by DFT calculations and characterizations.
A kind of bifunctional viologen‐containing covalent‐organic‐framework has been prepared and successfully applied in photothermal‐assisted co‐electrolysis of CO2 and methanol. The superior performance could be attributed to the cyclic diquats in Ni‐2CBpy2+‐COF that enhance the photothermal effect to accelerate faster charge‐transfer between catalyst and immediate species as well as higher selectivity towards desired products.
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