Inactive elemental doping is commonly used to improve the structural stability of high-voltage layered transition-metal oxide cathodes.However,the one-step co-doping strategy usually results in small grain size since ...Inactive elemental doping is commonly used to improve the structural stability of high-voltage layered transition-metal oxide cathodes.However,the one-step co-doping strategy usually results in small grain size since the low diffusivity ions such as Ti^(4+)will be concentrated on grain boundaries,which hinders the grain growth.In order to synthesize large single-crystal layered oxide cathodes,considering the different diffusivities of different dopant ions,we propose a simple two-step multi-element co-doping strategy to fabricate core–shell structured LiCoO_(2)(CS-LCO).In the current work,the high-diffusivity Al^(3+)/Mg^(2+)ions occupy the core of single-crystal grain while the low diffusivity Ti^(4+)ions enrich the shell layer.The Ti^(4+)-enriched shell layer(~12 nm)with Co/Ti substitution and stronger Ti–O bond gives rise to less oxygen ligand holes.In-situ XRD demonstrates the constrained contraction of c-axis lattice parameter and mitigated structural distortion.Under a high upper cut-off voltage of 4.6 V,the single-crystal CS-LCO maintains a reversible capacity of 159.8 mAh g^(−1)with a good retention of~89%after 300 cycles,and reaches a high specific capacity of 163.8 mAh g^(−1)at 5C.The proposed strategy can be extended to other pairs of low-(Zr^(4+),Ta^(5+),and W6+,etc.)and high-diffusivity cations(Zn^(2+),Ni^(2+),and Fe^(3+),etc.)for rational design of advanced layered oxide core–shell structured cathodes for lithium-ion batteries.展开更多
Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that ...Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that OI reflects defects in the activity of bone-forming osteoblasts,it is currently unclear whether OI also reflects defects in the many other cell types comprising bone,including defects in skeletal vascular endothelium or the skeletal stem cell populations that give rise to osteoblasts and whether correcting these broader defects could have therapeutic utility.展开更多
Lithium-ion batteries(LIBs)and lithium-sulfur(Li–S)batteries are two types of energy storage systems with significance in both scientific research and commercialization.Nevertheless,the rational design of electrode m...Lithium-ion batteries(LIBs)and lithium-sulfur(Li–S)batteries are two types of energy storage systems with significance in both scientific research and commercialization.Nevertheless,the rational design of electrode materials for overcoming the bottlenecks of LIBs and Li–S batteries(such as low diffusion rates in LIBs and low sulfur utilization in Li–S batteries)remain the greatest challenge,while two-dimensional(2D)electrodes materials provide a solution because of their unique structural and electrochemical properties.In this article,from the perspective of ab-initio simulations,we review the design of 2D electrode materials for LIBs and Li–S batteries.We first propose the theoretical design principles for 2D electrodes,including stability,electronic properties,capacity,and ion diffusion descriptors.Next,classified examples of promising 2D electrodes designed by theoretical simulations are given,covering graphene,phosphorene,MXene,transition metal sulfides,and so on.Finally,common challenges and a future perspective are provided.This review paves the way for rational design of 2D electrode materials for LIBs and Li–S battery applications and may provide a guide for future experiments.展开更多
<strong>Background: </strong>Adenoid cystic carcinoma (ACC) refers to a salivary gland neoplasm. Tracheal adenoid cystic carcinoma that invades the tracheal prominence is a relatively rare tumor among thor...<strong>Background: </strong>Adenoid cystic carcinoma (ACC) refers to a salivary gland neoplasm. Tracheal adenoid cystic carcinoma that invades the tracheal prominence is a relatively rare tumor among thoracic diseases.<strong> Objective: </strong>To explore the epidemiology, diagnosis, treatment and future development of tracheal adenoid cystic carcinoma (TACC). <strong>Methods:</strong> With asymptomatic invasion of the tracheal prominence, a case of tracheal adenoid cystic carcinoma with asymptomatic invasion of the tracheal prominence was reported. The clinical management process and surgical methods were introduced, and related literature was reviewed and summarized. <strong>Results: </strong>The patient was admitted due to tracheal augmentation mass for half a month. Chest CT at admission displayed the soft tissue density shadow behind the tracheal augmentation process. After the completion of other examinations, tracheal tumor resection and tracheal reconstruction were performed. Postoperative routine pathology exhibited that it was TACC and without inguinal lymph node metastasis. <strong>Conclusion:</strong> TACC is a low-grade tracheal tumor with low incidence, delayed clinical manifestations and lack of specificity as well. CT and bronchoscopy are helpful for the diagnosis of suspected patients. Meanwhile, radical surgical resection is the first choice of treatment. Adjuvant therapy can improve the therapeutic effect. Targeted immunotherapy is the developing direction of treatment.展开更多
g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photo...g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photoabsorption.Rationally designing g-C_(3)N_(4)-based heterojunction is promising for improving photocatalytic activity.Besides,g-C_(3)N_(4) exhibits great potentials in electrochemical energy storage.In view of the excellent performance of typical transition metal oxides(TMOs)in photocatalysis and energy storage,this review summarized the advances of TMOs/g-C_(3)N_(4) heterojunctions in the above two areas.Firstly,we introduce several typical TMOs based on their crystal structures and band structures.Then,we summarize different kinds of TMOs/g-C_(3)N_(4) heterojunctions,including type Ⅰ/Ⅱ heterojunction,Z-scheme,p-n junction and Schottky junction,with diverse photocatalytic applications(pollutant degradation,water splitting,CO_(2) reduction and N_(2) fixation)and supercapacitive energy storage.Finally,some promising strategies for improving the performance of TMOs/g-C_(3)N_(4) were proposed.Particularly,the exploration of photocatalysis-assisted supercapacitors was discussed.展开更多
Rational construction of highly efficient and cheap bifunctional electrocatalysts to boost both oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is extremely essential for the wide application of rechar...Rational construction of highly efficient and cheap bifunctional electrocatalysts to boost both oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is extremely essential for the wide application of rechargeable metal-air battery.In this work,we design a core-shell structural catalyst of CoNi dual-metal embedded in nitrogen doped porous carbon(NPC,CoNi@NPC),which is developed via the pyrolysis of CoNiMOFs,assisting by mesoporous SiO_(2) to effectively inhibit the aggregation of metal sites.Consequently,the asprepared CoNi@NPC manifests good ORR activity with half-wave potential up to 0.77 V.Specifically,the CoNi@NPC gives a very low OER over-potential of merely 101 mV in 6 M KOH along with high stability,outperforming the commercial Pt/C-RuO_(2).Moreover,the home-made zinc air battery with CoNi@NPC air cathode demonstrates excellent stability over long-term charging–discharging test,and delivers the maximum power density of 224 mW cm^(-2).The enhanced high performance of CoNi@NPC bifunctional catalyst for both ORR and OER can be ascribed to its unique core-shell structure and strong synergistic effect between the dual-bimetal active sites and the heteroatom doped carbon.This work opens a new avenue for the rational design of nonprecious metal bifunctional catalysts for rechargeable metal-air battery.展开更多
The ever-increasing demands for modern energy storage applications drive the search for novel anode materials of lithium(Li)-ion batteries(LIBs) with high storage capacity and long cycle life, to outperform the conven...The ever-increasing demands for modern energy storage applications drive the search for novel anode materials of lithium(Li)-ion batteries(LIBs) with high storage capacity and long cycle life, to outperform the conventional LIBs anode materials. Hence, we report amorphous ternary phosphorus chalcogenide(aP_(4)SSe_(2)) as an anode material with high performance for LIBs. Synthesized via the mechanochemistry method, the a-P_(4)SSe_(2) compound is endowed with amorphous feature and offers excellent cycling stability(over 1500 mA h g^(-1) capacity after 425 cycles at 0.3 A g^(-1)), owing to the advantages of isotropic nature and synergistic effect of multielement forming Li-ion conductors during battery operation. Furthermore,as confirmed by ex situ X-ray diffraction(XRD) and transmission electron microscope(TEM), the a-P_(4)SSe_(2)anode material has a reversible and multistage Li-storage mechanism, which is extremely beneficial to long cycle life for batteries. Moreover, the autogenous intermediate electrochemical products with fast ionic conductivity can facilitate Li-ion diffusion effectively. Thus, the a-P_(4)SSe_(2)electrode delivers excellent rate capability(730 mA h g^(-1)capacity at 3 A g^(-1)). Through in situ electrochemical impedance spectra(EIS) measurements, it can be revealed that the resistances of charge transfer(R_(SEI)) and solid electrolyte interphase(R_(Ct)) decrease along with the formation of Li-ion conductors whilst the ohmic resistance(R_(Ω)) remains unchanged during the whole electrochemical process, thus resulting in rapid reaction kinetics and stable electrode to obtain excellent rate performance and cycling ability for LIBs. Moreover, the formation mechanism and electrochemical superiority of the a-P_(4)SSe_(2)phase, and its expansion to P_(4)S_(3-x)Se_(x)(x = 0, 1, 2, 3) family can prove its significance for LIBs.展开更多
The development of efficient, durable and low cost electrocatalysts is crucial but extremely challenging for the oxygen evolution reaction (OER). Herein, we develop a self-template strategy to synthesize hollow Fe-dop...The development of efficient, durable and low cost electrocatalysts is crucial but extremely challenging for the oxygen evolution reaction (OER). Herein, we develop a self-template strategy to synthesize hollow Fe-doped CoP prisms (Fe-CoP) via ion exchange of cobalt acetate hydroxide with [Fe(CN)_(6)]^(3-) and phosphorization-induced transformation of CoFe-PBA (Co/Fe-containing prussian blue analogue) prisms in N2 atmosphere. The obtained Fe-CoP not only inherits the hollow prism-like morphology of CoFe-PBA, but also forms rich mesoporous channel. The Fe-CoP prisms exhibit extraordinary OER performances in 1.0 M KOH, with a low overpotential of 236 mV to deliver a current density of 10 mA cm^(−2) and a low Tafel slope of 32.9 mV dec^(–1). Moreover, the presented electrocatalyst shows good long-term operating durability and activity. The XPS and TEM analysis confirm that Fe-CoP has undergone surface reconstruction in the process of electrocatalytic OER, and the in situ formed oxides and oxyhydroxides are the real active species to boost OER. This work provides a promising pathway to the design and synthesis of efficient and robust electrocatalysts with hierarchical hollow structure for boosting OER.展开更多
Hepatocellular carcinoma(HCC)remains one of the most lethal malignancies.We previously demonstrated that the chromosome 19 microRNA cluster(C19MC)was associated with tumor burden and prognosis in patients with HCC.In ...Hepatocellular carcinoma(HCC)remains one of the most lethal malignancies.We previously demonstrated that the chromosome 19 microRNA cluster(C19MC)was associated with tumor burden and prognosis in patients with HCC.In the current study,we aim to explore the role of miR-516a-3p-an identical mature microRNA(miRNA)co-spliced by four oncogenic pre-miRNAs of C19MC(i.e.,mir-516a-1,mir-516a-2,mir-516b-1,and mir-516b-2)-in HCC.In our cohort of HCC patients,miR-516a-3p was highly expressed in HCC tissues in comparison with adjacent non-tumor tissues.High expression of tumor miR-516a-3p significantly correlated with advanced tumor stages,distinguished high HCC recurrence and mortality,and independently predicted poor prognosis.We further found that miR-516a-3p enhanced the proliferation,migration,and invasiveness of HCC cells in vitro and promoted tumor growth and metastasis in vivo.Among cancer cells,miR-516a-3p could be delivered via exosomes or extracellular vesicles and increased the oncogenic activity of recipient cells.Moreover,we performed comprehensive transcriptomics,proteomics,and metabolomics analysis on the potential mechanism underlying miR-516a-3p-promoted oncogenicity.MixOmic DIABLO analysis showed a close correlation and strong cluster consistency between the proteomics and metabolomics datasets.We further confirmed six proteins(i.e.,LMBR1,CHST9,RBM3,SLC7A6,PTGFRN,and NOL12)as the direct targets of miR-516a-3p and as central players in miR-516a-3p-mediated metabolism regulation.The integrated multi-omics and co-enriched pathway analysis showed that miR-516a-3p regulates the metabolic pathways of HCC cells,particularly purine and pyrimidine metabolism.In conclusion,our findings suggest that miR-516a-3p promotes malignant behaviors in HCC cells by regulating cellular metabolism and affecting neighboring cells via the exosome delivery system.Thus,we suggest miR-516a-3p as a novel molecular target for HCC therapy.展开更多
Most electrocatalysts are known to experience structural change during the oxygen evolution reaction(OER)process.Considerable endeavors have been dedicated thus far to comprehending the catalytic process and uncoverin...Most electrocatalysts are known to experience structural change during the oxygen evolution reaction(OER)process.Considerable endeavors have been dedicated thus far to comprehending the catalytic process and uncovering the underlying mechanism.During the dynamic evolution of catalyst structure,component leaching of electrocatalysts is the most common phenomenon.This article offers a concise overview of recent findings and developments related to the leaching phenomena in the OER process in terms of fundamental understanding of leaching,advanced characterization techniques used to investigate leaching,leaching of inactive components,and leaching of active components.Leaching behaviors and the induced effects in various kinds of OER catalysts are discussed,progress in manipulating leaching amount/degree toward a tunable surface evolution is spotlighted,and finally,three representative types of structure transformations induced by leaching metastable species in OER condition are proposed.By understanding the process of component leaching in the OER,it will provide more guidance for the rational design of superior electrocatalysts.展开更多
Our feet are often subjected to moist and warm environments,which can promote the growth of harmful bacteria and the development of severe infection in wounds located in the foot.As a result,there is a need for new an...Our feet are often subjected to moist and warm environments,which can promote the growth of harmful bacteria and the development of severe infection in wounds located in the foot.As a result,there is a need for new and innovative strategies to safely sterilize feet,when shoes are worn,to prevent any potential foot-related diseases.In this paper,we have produced a non-destructive,biocompatible and convenient-to-use insole by embedding a BaTiO3(BT)ferroelectric material into a conventional polydimethylsilane(PDMS)insole material to exploit a ferroelectric catalytic effect to promote the antibacterial and healing of infected wounds via the ferroelectric charges generated during walking.The formation of reactive oxygen species generated through a ferroelectric catalytic effect in the PDMS-BT composite is shown to increase the oxidative stress on bacteria and decrease both the activity of bacteria and the rate of formation of bacterial biofilms.In addition,the ferroelectric field generated by the PDMS-BT insole can enhance the level of transforming growth factor-beta and CD31 by influencing the endogenous electric field of a wound,thereby promoting the proliferation,differentiation of fibroblasts and angiogenesis.This work therefore provides a new route for antimicrobial and tissue reconstruction by integrating a ferroelectric biomaterial into a shoe insole,with significant potential for health-related applications.展开更多
Liver transplantation(LT)is the final treatment option for patients with end-stage liver disease.The increasing donor shortage results in the wide usage of grafts from extended criteria donors across the world.Using s...Liver transplantation(LT)is the final treatment option for patients with end-stage liver disease.The increasing donor shortage results in the wide usage of grafts from extended criteria donors across the world.Using such grafts is associated with the elevated incidences of post-transplant complications including initial nonfunction and ischemic biliary tract diseases,which significantly reduce recipient survival.Although several clinical factors have been demonstrated to impact donor liver quality,accurate,comprehensive,and effective assessment systems to guide decision-making for organ usage,restoration or discard are lacking.In addition,the development of biochemical technologies and bioinformatic analysis in recent years helps us better understand graft injury during the perioperative period and find potential ways to restore graft function.Moreover,such advances reveal the molecular profiles of grafts or perfusate that are susceptible to poor graft function and provide insight into finding novel biomarkers for graft quality assessment.Focusing on donors and grafts,we updated potential biomarkers in donor blood,liver tissue,or perfusates that predict graft quality following LT,and summarized strategies for restoring graft function in the era of extended criteria donors.In this review,we also discuss the advantages and drawbacks of these potential biomarkers and offer suggestions for future research.展开更多
Promoting industry applications of high-energy Li metal batteries(LMBs)is of vital importance for accelerating the electrification and decarbonization of our society.Unfortunately,the time-dependent storage aging of A...Promoting industry applications of high-energy Li metal batteries(LMBs)is of vital importance for accelerating the electrification and decarbonization of our society.Unfortunately,the time-dependent storage aging of Ah-level Li metal pouch cells,a ubiquitous but crucial practical indicator,has not yet been revealed.Herein,we first report the storage behaviors and multilateral synergistic aging mechanism of Ah-level NCM811jjLi pouch cells during the 120-day long-term storage under various conditions.Contrary to the conventional belief of Li-ion batteries with graphite intercalation anodes,the significant available capacity loss of 32.8%on average originates from the major electrolyte-sensitive anode corrosion and partial superimposed cathode degradation,and the irreversible capacity loss of 13.3%is essentially attributed to the unrecoverable interface/structure deterioration of NCM with further hindrance of the aged Li.Moreover,principles of alleviating aging have been proposed.This work bridges academia and industry and enriches the fundamental epistemology of storage aging of LMBs,shedding light on realistic applications of high-energy batteries.展开更多
Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for ex...Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for example,resonators,filters,or phase shifters.However,it is dificult to simultaneously achieve these characteristics by traditional strategies,such as doping and strain modifying.Here,we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc_(1/2)Nb_(1/2))_(0.9)(Mg_(1/3)Nb_(2/3))_(0.O3)(PSNMN)thin film can be almost doubled from~47%to~80.0%(at 10kHz)at a low electric field(~530kV/cm),and the dielectric loss can be sharply reduced by more than an order of magnitude,from~0.50 to~0.037(at 1 kHz)when the thin flm was annealed in air at 650℃ for 15h under the help of an atmosphere-compensating-block(ACB)made from the proto-PSNMN gel.Moreover,the PSNMN thin flm annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range(>130 K),which could be attributed to the Maxwell-Wagner(MW)effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process.The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possibie MW efects,and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy.The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'_(1/2)B"_(1/2))O3 ferroelectric thin films with a B-site nanoscale-ordered structure,meanwhile it paves the way for ultraintergrated tunable thin-flm-devices with great phase shifter performance in practical applications.展开更多
The complex degradation of metallic materials in aggressive environments can result in morphological and microstructural changes.The phase-field(PF)method is an effective computational approach to understanding and pr...The complex degradation of metallic materials in aggressive environments can result in morphological and microstructural changes.The phase-field(PF)method is an effective computational approach to understanding and predicting the morphology,phase change and/or transformation of materials.PF models are based on conserved and non-conserved field variables that represent each phase as a function of space and time coupled with time-dependent equations that describe the mechanisms.This report summarizes progress in the PF modeling of degradation of metallic materials in aqueous corrosion,hydrogen-assisted cracking,high-temperature metal oxidation in the gas phase and porous structure evolution with insights to future applications.展开更多
The creep behavior of a directionally solidified TiAl alloy with a high Nb content after microalloying by the addition of small amounts of W,Cr,and B elements was investigated by scanning electron microscopy and trans...The creep behavior of a directionally solidified TiAl alloy with a high Nb content after microalloying by the addition of small amounts of W,Cr,and B elements was investigated by scanning electron microscopy and transmission electron microscopy.By means of directional solidification and microalloying,a TiAl alloy with a fine and uniform microstructure and continuous columnar crystals was obtained.High-density dislocations,deformation nanotwins,and twin intersections were observed inγlamellae.The results show that,in comparison with the ternary TiAl alloy,the microalloyed high Nb containing TiAl alloy exhibited better creep properties at 760℃and 275 MPa.The decrease in stacking fault energy can promote dislocation dissociation and the formation of deformation twins,and the twin intersections can hinder the movement of dislocation to enhance the creep performance of the TiAl alloy.展开更多
Liver transplantation(LT)provides a cure for various end-stage liver diseases.The liver graft becomes the recipient’s new metabolic center,and donor genetics plays a potent role in the development of complications in...Liver transplantation(LT)provides a cure for various end-stage liver diseases.The liver graft becomes the recipient’s new metabolic center,and donor genetics plays a potent role in the development of complications in the recipient,such as metabolic disorders1 and even tumor recurrence.2 Notably,both the donor’s3 and recipient’s genetics4 contributes significantly to intrahepatic complications(e.g.,liver fibrosis and de novo steatosis).Therefore,crosstalk between donor and recipient tissue remodels the architecture and homeostasis of the transplanted liver,which is still a great challenge to explore.展开更多
The population trapping effect of the 3F4 level is an important factor limiting the power scaling of the 2.3 μm thulium(Tm)laser on the 3H4→3 H5 transition.In this Letter,we demonstrate a novel scheme of ground stat...The population trapping effect of the 3F4 level is an important factor limiting the power scaling of the 2.3 μm thulium(Tm)laser on the 3H4→3 H5 transition.In this Letter,we demonstrate a novel scheme of ground state absorption(GSA)(3 H6→3H4) and excited state absorption(ESA)(3F4→3H4] dual-wavelength pumped 2.3 μm Tm lasers.Introducing an ESA pumping process can accurately excite the Tm3+ ions accumulated in the 3F4 level to the 3H4 level,constructing a double populating mechanism for the upper laser level 3H4.A proof-of-principle experimental demonstration of the GSA(785 nm) and ESA(1470 nm) dual-wavelength pumped 2.3 μm Tm:LiYF4(Tm:YLF) laser was realized.A maximum continuous-wave output power of 1.84 W at 2308 nm was achieved under 785 and 1470 nm dual-wavelength pumping,increased by60% compared with the case of 785 nm single-wavelength pumping under the same resonator condition.Our work provides an efficient way to achieve higher output power from 2.3 μm Tm-doped lasers on the 3H4→3 H5 transition.展开更多
The deep-level traps induced by charged defects at the grain boundaries(GBs)of polycrystalline organic-inorganic halide perovskite(OIHP)films serve as major recombination centres,which limit the device performance.Her...The deep-level traps induced by charged defects at the grain boundaries(GBs)of polycrystalline organic-inorganic halide perovskite(OIHP)films serve as major recombination centres,which limit the device performance.Herein,we incorporate specially designed poly(3-aminothiophenol)-coated gold(Au@PAT)nanoparticles into the perovskite absorber,in order to examine the influence of plasmonic resonance on carrier dynamics in perovskite solar cells.Local changes in the photophysical properties of the OIHP films reveal that plasmon excitation could fill trap sites at the GB region through photo-brightening,whereas transient absorption spectroscopy and density functional theory calculations correlate this photo-brightening of trap states with plasmon-induced interfacial processes.As a result,the device achieved the best efficiency of 22.0%with robust operational stability.Our work provides unambiguous evidence for plasmon-induced trap occupation in OIHP and reveals that plasmonic nanostructures may be one type of efficient additives to overcome the recombination losses in perovskite solar cells and thin-film solar cells in general.展开更多
The electrocatalytic nitrogen reduction reaction(NRR)has been one of the most intriguing catalytic reactions in recent years,providing an energy-saving and environmentally friendly alternative to the conventional Habe...The electrocatalytic nitrogen reduction reaction(NRR)has been one of the most intriguing catalytic reactions in recent years,providing an energy-saving and environmentally friendly alternative to the conventional Haber–Bosch process for ammonia production.However,the activity and selectivity issues originating from the activation barrier of the NRR intermediates and the competing hydrogen evolution reaction result in the unsatisfactory NH_(3) yield rate and Faradaic efficiency of current NRR catalysts.Atomic site catalysts(ASCs),an emerging group of heterogeneous catalysts with a high atomic utilization rate,selectivity,and stability,may provide a solution.This article undertakes an exploration and systematic review of a highly significant research area:the principles of designing ASCs for the NRR.Both the theoretical and experimental progress and state-of-the-art techniques in the rational design of ASCs for the NRR are summarized,and the topic is extended to double-atom catalysts and boron-based metal-free ASCs.This review provides guidelines for the rational design of ASCs for the optimum activity and selectivity for the electrocatalytic NRR.展开更多
基金the Hong Kong Polytechnic University(Q-CDBG),the Science and Technology Program of Guangdong Province of China(2020A0505090001)the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.PolyU152178/20E)+2 种基金the National Natural Science Foundation of China(22379052)the Natural Science Foundation of Guangdong(No.2022A1515011667)China Postdoctoral Science Foundation(2021T140268).
文摘Inactive elemental doping is commonly used to improve the structural stability of high-voltage layered transition-metal oxide cathodes.However,the one-step co-doping strategy usually results in small grain size since the low diffusivity ions such as Ti^(4+)will be concentrated on grain boundaries,which hinders the grain growth.In order to synthesize large single-crystal layered oxide cathodes,considering the different diffusivities of different dopant ions,we propose a simple two-step multi-element co-doping strategy to fabricate core–shell structured LiCoO_(2)(CS-LCO).In the current work,the high-diffusivity Al^(3+)/Mg^(2+)ions occupy the core of single-crystal grain while the low diffusivity Ti^(4+)ions enrich the shell layer.The Ti^(4+)-enriched shell layer(~12 nm)with Co/Ti substitution and stronger Ti–O bond gives rise to less oxygen ligand holes.In-situ XRD demonstrates the constrained contraction of c-axis lattice parameter and mitigated structural distortion.Under a high upper cut-off voltage of 4.6 V,the single-crystal CS-LCO maintains a reversible capacity of 159.8 mAh g^(−1)with a good retention of~89%after 300 cycles,and reaches a high specific capacity of 163.8 mAh g^(−1)at 5C.The proposed strategy can be extended to other pairs of low-(Zr^(4+),Ta^(5+),and W6+,etc.)and high-diffusivity cations(Zn^(2+),Ni^(2+),and Fe^(3+),etc.)for rational design of advanced layered oxide core–shell structured cathodes for lithium-ion batteries.
基金supported by the National Natural Science Foundation of China (81972034,92068104 and 82002262 to R.X.)the National Key R&D Program of China (2020YFA0112900 to R.X.)+5 种基金Project of Xiamen Cell Therapy Research Center (3502Z20214001 to R.X.)supported by a the NIH grant of US (R01AR075585,R01HD115274,R01CA282815 to M.B.G.)Career Award for Medical Scientists from the Burroughs Wellcome Funda Pershing Square Sohn Cancer Research Alliance and the Maximizing Innovation in Neuroscience Discovery (MIND)Prizesupported by a Jump Start Research Career Development Award from Weill Cornell Medicinea Study Abroad Scholarships from the Mogam Science Scholarship Foundation。
文摘Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that OI reflects defects in the activity of bone-forming osteoblasts,it is currently unclear whether OI also reflects defects in the many other cell types comprising bone,including defects in skeletal vascular endothelium or the skeletal stem cell populations that give rise to osteoblasts and whether correcting these broader defects could have therapeutic utility.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China(PolyU152178/20 E)the Hong Kong Polytechnic University(1-W19S)Science and Technology Program of Guangdong Province of China(2020A0505090001).
文摘Lithium-ion batteries(LIBs)and lithium-sulfur(Li–S)batteries are two types of energy storage systems with significance in both scientific research and commercialization.Nevertheless,the rational design of electrode materials for overcoming the bottlenecks of LIBs and Li–S batteries(such as low diffusion rates in LIBs and low sulfur utilization in Li–S batteries)remain the greatest challenge,while two-dimensional(2D)electrodes materials provide a solution because of their unique structural and electrochemical properties.In this article,from the perspective of ab-initio simulations,we review the design of 2D electrode materials for LIBs and Li–S batteries.We first propose the theoretical design principles for 2D electrodes,including stability,electronic properties,capacity,and ion diffusion descriptors.Next,classified examples of promising 2D electrodes designed by theoretical simulations are given,covering graphene,phosphorene,MXene,transition metal sulfides,and so on.Finally,common challenges and a future perspective are provided.This review paves the way for rational design of 2D electrode materials for LIBs and Li–S battery applications and may provide a guide for future experiments.
文摘<strong>Background: </strong>Adenoid cystic carcinoma (ACC) refers to a salivary gland neoplasm. Tracheal adenoid cystic carcinoma that invades the tracheal prominence is a relatively rare tumor among thoracic diseases.<strong> Objective: </strong>To explore the epidemiology, diagnosis, treatment and future development of tracheal adenoid cystic carcinoma (TACC). <strong>Methods:</strong> With asymptomatic invasion of the tracheal prominence, a case of tracheal adenoid cystic carcinoma with asymptomatic invasion of the tracheal prominence was reported. The clinical management process and surgical methods were introduced, and related literature was reviewed and summarized. <strong>Results: </strong>The patient was admitted due to tracheal augmentation mass for half a month. Chest CT at admission displayed the soft tissue density shadow behind the tracheal augmentation process. After the completion of other examinations, tracheal tumor resection and tracheal reconstruction were performed. Postoperative routine pathology exhibited that it was TACC and without inguinal lymph node metastasis. <strong>Conclusion:</strong> TACC is a low-grade tracheal tumor with low incidence, delayed clinical manifestations and lack of specificity as well. CT and bronchoscopy are helpful for the diagnosis of suspected patients. Meanwhile, radical surgical resection is the first choice of treatment. Adjuvant therapy can improve the therapeutic effect. Targeted immunotherapy is the developing direction of treatment.
基金financially supported by the National Natural Science Foundation (No.52072347, 51972288, 51672258 and 51572246)the Fundamental Research Funds for the Central Universities (No. 2652019144 and 2652018287)+1 种基金the financial supports from the Science and Technology Program of Guangdong Province (2019A050510012)Shenzhen Science, Technology and Innovation Commission (SGDX2019081623240364).
文摘g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photoabsorption.Rationally designing g-C_(3)N_(4)-based heterojunction is promising for improving photocatalytic activity.Besides,g-C_(3)N_(4) exhibits great potentials in electrochemical energy storage.In view of the excellent performance of typical transition metal oxides(TMOs)in photocatalysis and energy storage,this review summarized the advances of TMOs/g-C_(3)N_(4) heterojunctions in the above two areas.Firstly,we introduce several typical TMOs based on their crystal structures and band structures.Then,we summarize different kinds of TMOs/g-C_(3)N_(4) heterojunctions,including type Ⅰ/Ⅱ heterojunction,Z-scheme,p-n junction and Schottky junction,with diverse photocatalytic applications(pollutant degradation,water splitting,CO_(2) reduction and N_(2) fixation)and supercapacitive energy storage.Finally,some promising strategies for improving the performance of TMOs/g-C_(3)N_(4) were proposed.Particularly,the exploration of photocatalysis-assisted supercapacitors was discussed.
基金supported by National Natural Science Foundation of China(21972017)the“Scientific and Technical Innovation Action Plan”Hong Kong,MacaoTaiwan Science&Technology Cooperation Project of Shanghai Science and Technology Committee(19160760600).
文摘Rational construction of highly efficient and cheap bifunctional electrocatalysts to boost both oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is extremely essential for the wide application of rechargeable metal-air battery.In this work,we design a core-shell structural catalyst of CoNi dual-metal embedded in nitrogen doped porous carbon(NPC,CoNi@NPC),which is developed via the pyrolysis of CoNiMOFs,assisting by mesoporous SiO_(2) to effectively inhibit the aggregation of metal sites.Consequently,the asprepared CoNi@NPC manifests good ORR activity with half-wave potential up to 0.77 V.Specifically,the CoNi@NPC gives a very low OER over-potential of merely 101 mV in 6 M KOH along with high stability,outperforming the commercial Pt/C-RuO_(2).Moreover,the home-made zinc air battery with CoNi@NPC air cathode demonstrates excellent stability over long-term charging–discharging test,and delivers the maximum power density of 224 mW cm^(-2).The enhanced high performance of CoNi@NPC bifunctional catalyst for both ORR and OER can be ascribed to its unique core-shell structure and strong synergistic effect between the dual-bimetal active sites and the heteroatom doped carbon.This work opens a new avenue for the rational design of nonprecious metal bifunctional catalysts for rechargeable metal-air battery.
基金supported by the Regional Innovation and Development Joint Fundthe National Natural Science Foundation of China (Grant No. U20A20249)+1 种基金the Science and Technology Program of Guangdong Province of China (Grant No.2019A050510012, 2020A050515007, 2020A0505090001)the Guangzhou emerging industry development fund project of Guangzhou development and reform commission。
文摘The ever-increasing demands for modern energy storage applications drive the search for novel anode materials of lithium(Li)-ion batteries(LIBs) with high storage capacity and long cycle life, to outperform the conventional LIBs anode materials. Hence, we report amorphous ternary phosphorus chalcogenide(aP_(4)SSe_(2)) as an anode material with high performance for LIBs. Synthesized via the mechanochemistry method, the a-P_(4)SSe_(2) compound is endowed with amorphous feature and offers excellent cycling stability(over 1500 mA h g^(-1) capacity after 425 cycles at 0.3 A g^(-1)), owing to the advantages of isotropic nature and synergistic effect of multielement forming Li-ion conductors during battery operation. Furthermore,as confirmed by ex situ X-ray diffraction(XRD) and transmission electron microscope(TEM), the a-P_(4)SSe_(2)anode material has a reversible and multistage Li-storage mechanism, which is extremely beneficial to long cycle life for batteries. Moreover, the autogenous intermediate electrochemical products with fast ionic conductivity can facilitate Li-ion diffusion effectively. Thus, the a-P_(4)SSe_(2)electrode delivers excellent rate capability(730 mA h g^(-1)capacity at 3 A g^(-1)). Through in situ electrochemical impedance spectra(EIS) measurements, it can be revealed that the resistances of charge transfer(R_(SEI)) and solid electrolyte interphase(R_(Ct)) decrease along with the formation of Li-ion conductors whilst the ohmic resistance(R_(Ω)) remains unchanged during the whole electrochemical process, thus resulting in rapid reaction kinetics and stable electrode to obtain excellent rate performance and cycling ability for LIBs. Moreover, the formation mechanism and electrochemical superiority of the a-P_(4)SSe_(2)phase, and its expansion to P_(4)S_(3-x)Se_(x)(x = 0, 1, 2, 3) family can prove its significance for LIBs.
基金Financial support from the National Natural Science Fundation of China(no.22072018,21703040,51873037 and 21973013).
文摘The development of efficient, durable and low cost electrocatalysts is crucial but extremely challenging for the oxygen evolution reaction (OER). Herein, we develop a self-template strategy to synthesize hollow Fe-doped CoP prisms (Fe-CoP) via ion exchange of cobalt acetate hydroxide with [Fe(CN)_(6)]^(3-) and phosphorization-induced transformation of CoFe-PBA (Co/Fe-containing prussian blue analogue) prisms in N2 atmosphere. The obtained Fe-CoP not only inherits the hollow prism-like morphology of CoFe-PBA, but also forms rich mesoporous channel. The Fe-CoP prisms exhibit extraordinary OER performances in 1.0 M KOH, with a low overpotential of 236 mV to deliver a current density of 10 mA cm^(−2) and a low Tafel slope of 32.9 mV dec^(–1). Moreover, the presented electrocatalyst shows good long-term operating durability and activity. The XPS and TEM analysis confirm that Fe-CoP has undergone surface reconstruction in the process of electrocatalytic OER, and the in situ formed oxides and oxyhydroxides are the real active species to boost OER. This work provides a promising pathway to the design and synthesis of efficient and robust electrocatalysts with hierarchical hollow structure for boosting OER.
基金supported by the National Natural Science Foundation of China(81771713 and 81721091)the Zhejiang Provincial Natural Science Foundation of China(LR18H030001)。
文摘Hepatocellular carcinoma(HCC)remains one of the most lethal malignancies.We previously demonstrated that the chromosome 19 microRNA cluster(C19MC)was associated with tumor burden and prognosis in patients with HCC.In the current study,we aim to explore the role of miR-516a-3p-an identical mature microRNA(miRNA)co-spliced by four oncogenic pre-miRNAs of C19MC(i.e.,mir-516a-1,mir-516a-2,mir-516b-1,and mir-516b-2)-in HCC.In our cohort of HCC patients,miR-516a-3p was highly expressed in HCC tissues in comparison with adjacent non-tumor tissues.High expression of tumor miR-516a-3p significantly correlated with advanced tumor stages,distinguished high HCC recurrence and mortality,and independently predicted poor prognosis.We further found that miR-516a-3p enhanced the proliferation,migration,and invasiveness of HCC cells in vitro and promoted tumor growth and metastasis in vivo.Among cancer cells,miR-516a-3p could be delivered via exosomes or extracellular vesicles and increased the oncogenic activity of recipient cells.Moreover,we performed comprehensive transcriptomics,proteomics,and metabolomics analysis on the potential mechanism underlying miR-516a-3p-promoted oncogenicity.MixOmic DIABLO analysis showed a close correlation and strong cluster consistency between the proteomics and metabolomics datasets.We further confirmed six proteins(i.e.,LMBR1,CHST9,RBM3,SLC7A6,PTGFRN,and NOL12)as the direct targets of miR-516a-3p and as central players in miR-516a-3p-mediated metabolism regulation.The integrated multi-omics and co-enriched pathway analysis showed that miR-516a-3p regulates the metabolic pathways of HCC cells,particularly purine and pyrimidine metabolism.In conclusion,our findings suggest that miR-516a-3p promotes malignant behaviors in HCC cells by regulating cellular metabolism and affecting neighboring cells via the exosome delivery system.Thus,we suggest miR-516a-3p as a novel molecular target for HCC therapy.
基金supported by the Program for Jiangsu Spe-cially-Appointed Professors(R2023T05,YQR23123)the Startup Foundation for Introducing Talent of NUIST(2024R078)supported by the Hong Kong Polytechnic University(1-WZ5L,Q-CDBG,and 1-ZE2F).
文摘Most electrocatalysts are known to experience structural change during the oxygen evolution reaction(OER)process.Considerable endeavors have been dedicated thus far to comprehending the catalytic process and uncovering the underlying mechanism.During the dynamic evolution of catalyst structure,component leaching of electrocatalysts is the most common phenomenon.This article offers a concise overview of recent findings and developments related to the leaching phenomena in the OER process in terms of fundamental understanding of leaching,advanced characterization techniques used to investigate leaching,leaching of inactive components,and leaching of active components.Leaching behaviors and the induced effects in various kinds of OER catalysts are discussed,progress in manipulating leaching amount/degree toward a tunable surface evolution is spotlighted,and finally,three representative types of structure transformations induced by leaching metastable species in OER condition are proposed.By understanding the process of component leaching in the OER,it will provide more guidance for the rational design of superior electrocatalysts.
基金National Natural Science Foundation of China,Grant/Award Numbers:52172265,5230130435Scientific research project of Hunan Provincial Department of Education,Grant/Award Number:21B0009+2 种基金Hunan Excellent Youth Science Foundation,Grant/Award Number:2022JJ20067State Key Laboratory of Powder Metallurgy,Central South University,Changsha,Chinathe Hong Kong Polytechnic University,Grant/Award Number:1-W34B。
文摘Our feet are often subjected to moist and warm environments,which can promote the growth of harmful bacteria and the development of severe infection in wounds located in the foot.As a result,there is a need for new and innovative strategies to safely sterilize feet,when shoes are worn,to prevent any potential foot-related diseases.In this paper,we have produced a non-destructive,biocompatible and convenient-to-use insole by embedding a BaTiO3(BT)ferroelectric material into a conventional polydimethylsilane(PDMS)insole material to exploit a ferroelectric catalytic effect to promote the antibacterial and healing of infected wounds via the ferroelectric charges generated during walking.The formation of reactive oxygen species generated through a ferroelectric catalytic effect in the PDMS-BT composite is shown to increase the oxidative stress on bacteria and decrease both the activity of bacteria and the rate of formation of bacterial biofilms.In addition,the ferroelectric field generated by the PDMS-BT insole can enhance the level of transforming growth factor-beta and CD31 by influencing the endogenous electric field of a wound,thereby promoting the proliferation,differentiation of fibroblasts and angiogenesis.This work therefore provides a new route for antimicrobial and tissue reconstruction by integrating a ferroelectric biomaterial into a shoe insole,with significant potential for health-related applications.
基金funded by the National Natural Science Foundation of China (No.82171757)the Zhejiang Province Natural Science Foundation of China (No.LZ22H030004).
文摘Liver transplantation(LT)is the final treatment option for patients with end-stage liver disease.The increasing donor shortage results in the wide usage of grafts from extended criteria donors across the world.Using such grafts is associated with the elevated incidences of post-transplant complications including initial nonfunction and ischemic biliary tract diseases,which significantly reduce recipient survival.Although several clinical factors have been demonstrated to impact donor liver quality,accurate,comprehensive,and effective assessment systems to guide decision-making for organ usage,restoration or discard are lacking.In addition,the development of biochemical technologies and bioinformatic analysis in recent years helps us better understand graft injury during the perioperative period and find potential ways to restore graft function.Moreover,such advances reveal the molecular profiles of grafts or perfusate that are susceptible to poor graft function and provide insight into finding novel biomarkers for graft quality assessment.Focusing on donors and grafts,we updated potential biomarkers in donor blood,liver tissue,or perfusates that predict graft quality following LT,and summarized strategies for restoring graft function in the era of extended criteria donors.In this review,we also discuss the advantages and drawbacks of these potential biomarkers and offer suggestions for future research.
基金National Natural Science Foundation of China,Grant/Award Numbers:51974256,52034011The Outstanding Young Scholars of Shaanxi,Grant/Award Number:2019JC-12+3 种基金The Natural Science Basic Research Plan in Shaanxi Province of China,Grant/Award Numbers:2019JLZ-01,2019JLM-29Fundamental Research Funds for the Central Universities,Grant/Award Numbers:3102021ZD0401,3102021TS0406,3102019JC005the Youth Innovation Team of Shaanxi UniversitiesND Basic Research Funds,Grant/Award Number:G2022WD。
文摘Promoting industry applications of high-energy Li metal batteries(LMBs)is of vital importance for accelerating the electrification and decarbonization of our society.Unfortunately,the time-dependent storage aging of Ah-level Li metal pouch cells,a ubiquitous but crucial practical indicator,has not yet been revealed.Herein,we first report the storage behaviors and multilateral synergistic aging mechanism of Ah-level NCM811jjLi pouch cells during the 120-day long-term storage under various conditions.Contrary to the conventional belief of Li-ion batteries with graphite intercalation anodes,the significant available capacity loss of 32.8%on average originates from the major electrolyte-sensitive anode corrosion and partial superimposed cathode degradation,and the irreversible capacity loss of 13.3%is essentially attributed to the unrecoverable interface/structure deterioration of NCM with further hindrance of the aged Li.Moreover,principles of alleviating aging have been proposed.This work bridges academia and industry and enriches the fundamental epistemology of storage aging of LMBs,shedding light on realistic applications of high-energy batteries.
基金supported by the National Natural Science Foundation of China(51402196,52072218,52192613)the National Key Research and Development Program of China(2021YFB3601504)the Natural Science Foundation of Shandong Province(ZR2022YQ43).
文摘Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for example,resonators,filters,or phase shifters.However,it is dificult to simultaneously achieve these characteristics by traditional strategies,such as doping and strain modifying.Here,we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc_(1/2)Nb_(1/2))_(0.9)(Mg_(1/3)Nb_(2/3))_(0.O3)(PSNMN)thin film can be almost doubled from~47%to~80.0%(at 10kHz)at a low electric field(~530kV/cm),and the dielectric loss can be sharply reduced by more than an order of magnitude,from~0.50 to~0.037(at 1 kHz)when the thin flm was annealed in air at 650℃ for 15h under the help of an atmosphere-compensating-block(ACB)made from the proto-PSNMN gel.Moreover,the PSNMN thin flm annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range(>130 K),which could be attributed to the Maxwell-Wagner(MW)effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process.The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possibie MW efects,and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy.The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'_(1/2)B"_(1/2))O3 ferroelectric thin films with a B-site nanoscale-ordered structure,meanwhile it paves the way for ultraintergrated tunable thin-flm-devices with great phase shifter performance in practical applications.
基金This work was supported by grants from the Research Grants Council of Hong Kong(PolyU152174/17E,PolyU152208/18E,and PolyU152178/20E)the Science and Technology Program of Guangdong Province of China(2020A0505090001).
文摘The complex degradation of metallic materials in aggressive environments can result in morphological and microstructural changes.The phase-field(PF)method is an effective computational approach to understanding and predicting the morphology,phase change and/or transformation of materials.PF models are based on conserved and non-conserved field variables that represent each phase as a function of space and time coupled with time-dependent equations that describe the mechanisms.This report summarizes progress in the PF modeling of degradation of metallic materials in aqueous corrosion,hydrogen-assisted cracking,high-temperature metal oxidation in the gas phase and porous structure evolution with insights to future applications.
基金the National Natural Science Foundation of China(Nos.52171112,and 51671072)。
文摘The creep behavior of a directionally solidified TiAl alloy with a high Nb content after microalloying by the addition of small amounts of W,Cr,and B elements was investigated by scanning electron microscopy and transmission electron microscopy.By means of directional solidification and microalloying,a TiAl alloy with a fine and uniform microstructure and continuous columnar crystals was obtained.High-density dislocations,deformation nanotwins,and twin intersections were observed inγlamellae.The results show that,in comparison with the ternary TiAl alloy,the microalloyed high Nb containing TiAl alloy exhibited better creep properties at 760℃and 275 MPa.The decrease in stacking fault energy can promote dislocation dissociation and the formation of deformation twins,and the twin intersections can hinder the movement of dislocation to enhance the creep performance of the TiAl alloy.
基金supported by the National Natural Science Foundation of China(81771713)the Zhejiang Provincial Natural Science Foundation of China(LR18H030001)the Fundamental Research Funds for the Central Universities(2019QNA7030).
文摘Liver transplantation(LT)provides a cure for various end-stage liver diseases.The liver graft becomes the recipient’s new metabolic center,and donor genetics plays a potent role in the development of complications in the recipient,such as metabolic disorders1 and even tumor recurrence.2 Notably,both the donor’s3 and recipient’s genetics4 contributes significantly to intrahepatic complications(e.g.,liver fibrosis and de novo steatosis).Therefore,crosstalk between donor and recipient tissue remodels the architecture and homeostasis of the transplanted liver,which is still a great challenge to explore.
基金supported by the National Natural Science Foundation of China (Nos. 61875077, 61911530131, and U1730119)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No. 18KJA510001)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The population trapping effect of the 3F4 level is an important factor limiting the power scaling of the 2.3 μm thulium(Tm)laser on the 3H4→3 H5 transition.In this Letter,we demonstrate a novel scheme of ground state absorption(GSA)(3 H6→3H4) and excited state absorption(ESA)(3F4→3H4] dual-wavelength pumped 2.3 μm Tm lasers.Introducing an ESA pumping process can accurately excite the Tm3+ ions accumulated in the 3F4 level to the 3H4 level,constructing a double populating mechanism for the upper laser level 3H4.A proof-of-principle experimental demonstration of the GSA(785 nm) and ESA(1470 nm) dual-wavelength pumped 2.3 μm Tm:LiYF4(Tm:YLF) laser was realized.A maximum continuous-wave output power of 1.84 W at 2308 nm was achieved under 785 and 1470 nm dual-wavelength pumping,increased by60% compared with the case of 785 nm single-wavelength pumping under the same resonator condition.Our work provides an efficient way to achieve higher output power from 2.3 μm Tm-doped lasers on the 3H4→3 H5 transition.
基金This work was supported by the National Natural Science Foundation of China(Grants 51863013 and 61874052)K.Y.thanks the financial support of Excellent Young Foundation of Jiangxi Province(Grant 20192BCB23009)+3 种基金the Hong Kong Scholars programme(XJ2016048)P.D.and T.S.thank the financial support of the Grant agency of the Czech Republic(number 20-01673S)This work was also supported by the Hong Kong Polytechnic University(G-YZ98)the Research Grants Council of Hong Kong(GRF Grant number PolyU152140/19E and CRF Grant number C5037-18G).
文摘The deep-level traps induced by charged defects at the grain boundaries(GBs)of polycrystalline organic-inorganic halide perovskite(OIHP)films serve as major recombination centres,which limit the device performance.Herein,we incorporate specially designed poly(3-aminothiophenol)-coated gold(Au@PAT)nanoparticles into the perovskite absorber,in order to examine the influence of plasmonic resonance on carrier dynamics in perovskite solar cells.Local changes in the photophysical properties of the OIHP films reveal that plasmon excitation could fill trap sites at the GB region through photo-brightening,whereas transient absorption spectroscopy and density functional theory calculations correlate this photo-brightening of trap states with plasmon-induced interfacial processes.As a result,the device achieved the best efficiency of 22.0%with robust operational stability.Our work provides unambiguous evidence for plasmon-induced trap occupation in OIHP and reveals that plasmonic nanostructures may be one type of efficient additives to overcome the recombination losses in perovskite solar cells and thin-film solar cells in general.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.PolyU152140/19E)the Hong Kong Polytechnic University.The authors appreciate the support of the“Scientific and Technical Innovation Action Plan”Hong Kong,Macao and Taiwan Science&Technology Cooperation Project of Shanghai Science and Technology Committee(19160760600).
文摘The electrocatalytic nitrogen reduction reaction(NRR)has been one of the most intriguing catalytic reactions in recent years,providing an energy-saving and environmentally friendly alternative to the conventional Haber–Bosch process for ammonia production.However,the activity and selectivity issues originating from the activation barrier of the NRR intermediates and the competing hydrogen evolution reaction result in the unsatisfactory NH_(3) yield rate and Faradaic efficiency of current NRR catalysts.Atomic site catalysts(ASCs),an emerging group of heterogeneous catalysts with a high atomic utilization rate,selectivity,and stability,may provide a solution.This article undertakes an exploration and systematic review of a highly significant research area:the principles of designing ASCs for the NRR.Both the theoretical and experimental progress and state-of-the-art techniques in the rational design of ASCs for the NRR are summarized,and the topic is extended to double-atom catalysts and boron-based metal-free ASCs.This review provides guidelines for the rational design of ASCs for the optimum activity and selectivity for the electrocatalytic NRR.
