Development and Innovation of Modern Microvascular Anastomoses

High-quality microvascular anastomosis is the foundation of successful microsurgery and one of the most important basic skills for microsurgeons. The traditional manual suture is recognized as the “gold standard” for microvascular anastomosis, but it still has problems such as long operation time and easy to cause vascular damage. In order to improve the success rate of microvascular anastomosis, reduce surgical complications and make the prognosis of patients better. In order to improve the success rate of microvascular anastomosis and reduce the surgical complications, scholars at home and abroad have developed some new vascular anastomosis techniques that are simple, fast and minimally invasive while improving the traditional surgical suturing methods. In this paper, we review the microvascular anastomosis, and its application research in two methods of traditional hand suture and non-suture anastomosis, in order to promote the application development of microvascular anastomosis.

Hybrid reconstruction framework for model-based multispectral bioluminescence tomography based on Alpha-divergence

Bioluminescence tomography(BLT)is a promising imaging modality that can provide noninvasive three-dimensional visualization information on tumor distribution.In BLT reconstruction,the widely used methods based on regularization or greedy strategy face problems such as over-sparsity,over-smoothing,spatial discontinuity,poor robustness,and poor multi-target resolution.To deal with these problems,combining the advantages of the greedy strategies as well as regularization methods,we propose a hybrid reconstruction framework for model-based multispectral BLT using the support set of a greedy strategy as a feasible region and the Alpha-divergence to combine the weighted solutions obtained by L1-norm and L2-norm regularization methods.In numerical simulations with digital mouse and in vivo experiments,the results show that the proposed framework has better localization accuracy,spatial resolution,and multi-target resolution.

The mechanism and risk factors for immune checkpoint inhibitor pneumonitis in non-small cell lung cancer patients

Immune checkpoint inhibitors(ICIs)are new and promising therapeutic agents for non-small cell lung cancer(NSCLC).However,along with demonstrating remarkable efficacy,ICIs can also trigger immune-related adverse events.Checkpoint inhibitor pneumonitis(CIP)has been reported to have a morbidity rate of 3%to 5%and a mortality rate of 10%to 17%.Moreover,the incidence of CIP in NSCLC is higher than that in other tumor types,reaching 7%to 13%.With the increased use of ICIs in NSCLC,CIP has drawn extensive attention from oncologists and cancer researchers.Identifying high risk factors for CIP and the potential mechanism of CIP are key points in preventing and monitoring serious adverse events.In this review,the results of our analysis and summary of previous studies suggested that the risk factors for CIP may include previous lung disease,prior thoracic irradiation,and combinations with other drugs.Our review also explored potential mechanisms closely related toCIP,including increasedT cell activity against associated antigens in tumor and normal tissues,preexisting autoantibodies,and inflammatory cytokines.

Adaptive hp finite element method for fluorescence molecular tomography with simplified spherical harmonics approximation

Recently,the simplified spherical harmonics equations(SP)model has at tracted much att entionin modeling the light propagation in small tissue ggeometriesat visible and near-infrared wave-leng ths.In this paper,we report an eficient numerical method for fluorescence moleeular tom-ography(FMT)that combines the advantage of SP model and adaptive hp finite elementmethod(hp-FEM).For purposes of comparison,hp-FEM and h-FEM are,respectively applied tothe reconstruction pro cess with diffusion approximation and SPs model.Simulation experiments on a 3D digital mouse atlas and physical experiments on a phantom are designed to evaluate thereconstruction methods in terms of the location and the reconstructed fluorescent yield.Theexperimental results demonstrate that hp-FEM with SPy model,yield more accurate results thanh-FEM with difusion approximation model does.The phantom experiments show the potentialand feasibility of the proposed approach in FMT applications.

Alkali metal cation effects on electrocatalytic CO_(2)reduction with iron porphyrins

The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has attracted increasing attention in recentyears.Practical electrocatalysis of CO_(2)RR must be carried out in aqueous solutions containing electrolytesof alkali metal cations such as sodium and potassium.Although considerable efforts havebeen made to design efficient electrocatalysts for CO_(2)RR and to investigate the structure–activityrelationships using molecular model complexes,only a few studies have been investigated the effectof alkali metal cations on electrocatalytic CO_(2)RR.In this study,we report the effect of alkali metalcations(Na^(+)and K^(+))on electrocatalytic CO_(2)RR with Fe porphyrins.By running CO_(2)RR electrocatalysisin dimethylformamide(DMF),we found that the addition of Na^(+)or K^(+)considerably improves thecatalytic activity of Fe chloride tetrakis(3,4,5‐trimethoxyphenyl)porphyrin(FeP).Based on thisresult,we synthesized an Fe porphyrin^(N)18C6‐FeP bearing a tethered 1‐aza‐18‐crown‐6‐ether(^(N)18C6)group at the second coordination sphere of the Fe site.We showed that with the tethered^(N)18C6 to bind Na^(+)or K^(+),^(N)18C6‐FeP is more active than FeP for electrocatalytic CO_(2)RR.This workdemonstrates the positive effect of alkali metal cations to improve CO_(2)RR electrocatalysis,which isvaluable for the rational design of new efficient catalysts.

Comparing electrocatalytic hydrogen and oxygen evolution activities of first-row transition metal complexes with similar coordination environments

Developing cheap and efficient electrocatalysts for water splitting is required for energy conversion techniques.Many first-row transition metal complexes have been shown to be active for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Metal ions play crucial roles in these catalytic processes,but the activity dependence on the nature of metal ions has been rarely studied due to the difficulty to compare metal complexes with different coordination environments.We herein reported the synthesis of a series of metal complexes of azido-substituted porphyrin(1),in which metal ions have very similar coordination environments.By grafting 1-M(M=Mn,Fe,Co,Ni,and Cu)onto alkynefunctionalized carbon nanotubes(CNTs)through the same covalent connection,the resulted hybrids 1-M@CNT were all active and robust for both electrocatalytic HER and OER in alkaline aqueous solutions.Among these hybrids,1-Fe@CNT displayed the highest electrocatalytic activity for HER,while 1-Co@CNT was the most active one for OER.Moreover,a two-electrode water electrolysis cell assembled with 1-Fe@CNT as the cathode and 1-Co@CNT as the anode required smaller applied bias potential by210 mV to get 10 mA/cm^(2)current density as compared to that assembled with Pt/C and Ir/C with the same amount of metal loading.This work is significant to correlate HER and OER activity with the nature of first-row transition metal ions and to highlight promising potential applications of molecular electrocatalysis in water splitting.

Effective and robust approach for fluorescence molecular tomography based on CoSaMP and SP_(3)model

Fluorescence molecular tomography(FMT)allows the detection and quantification of various biological processes in small animals in vrivo,which expands the horizons of pre clinical rescarch and drug development.Eficient three dimensional(3D)reconstruction algorithm is the key to accurate localization and quant ification of fAuorescent target in FMT.In this paper,3D recon-struction of FMT is regarded as a sparse signal recovery problem and the compressive sampling matching pursuit(CoSaMP)algorithm is adopted to obtain greedy recovery of fuorescent sig-nals.Moreover,to reduce the modeling error,the simplified spherical harmonics approximation to the radiative transfer equation(RTE),more specifically SP_(3),is utilized to describe light prop-agation in biological tissues.The performance of the proposed reconstruction method is thor-oughly evaluated by simulations on a 3D digital mouse model by comparing it with three representative greedy methods including orthogonal matching pursuit(OMP),stagewise OMP(StOMP),and regularized OMP(ROMP).The CoSaMP combined with SP_(3)shows an im-provement in reconstruction accuracy and exhibits distinct advantages over the comparative algorithms in multiple targets resolving.Stability analysis suggests that CoSaMP is robust to noise and performs stably with reduction of measurements.The feasibility and reoonstruction accuracy of the proposed method are further validated by phantom experimental data.

Iron porphyrin with appended guanidyl group for significantly improved electrocatalytic carbon dioxide reduction activity and selectivity in aqueous solutions

Iron porphyrins have high activity and selectivity for electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in nonaqueous solutions,but they usually display poor or moderate selectivity for CO_(2)RR in aqueous solutions because of the competitive hydrogen evolution reaction.Using water as the electrocatalytic reaction solvent is more favored because not only it is cheap,green and abundant but also it can sufficiently provide protons required for CO_(2)RR.Therefore,developing Fe porphyrins as electrocatalysts for efficient and selective CO_(2)RR in aqueous solutions is of both fundamental and practical significance.Herein,we report the design and synthesis of Fe porphyrin 1 with an appended guanidyl group and its electrocatalytic features for CO_(2)RR in both nonaqueous and aqueous solutions.In acetonitrile,Fe porphyrin 1 and its guanidyl-free analogue,tetrakis(3,4,5-trimethoxyphenyl)porphyrin 2,are both efficient for electrocatalytic CO_(2)-to-CO conversion,but the turnover frequency with 1(3.9´10^(5)s^(-1))is one order of magnitude larger than that with 2(1.7´10^(4)s^(-1)),showing the critical role of the appended guanidyl group in improving electrocatalytic CO_(2)RR activity.More importantly,in 0.1 mol L^(-1)KHCO_(3)aqueous solutions,1 showed very high selectivity for electrocatalytic CO_(2)-to-CO conversion with a Faradaic efficiency of 96%,while 2 displayed a Faradaic efficiency of 65%for the CO_(2)-to-CO conversion.This work is of significance to show the effect of appended guanidyl group on improving both activity and selectivity of Fe porphyrins for CO_(2)RR electrocatalysis.

Analysis on clinical distribution and drug resistance of Klebsiella pneumoniae isolated for 5 consecutive years

Objective:To analyze the clinical distribution and drug resistance of Klebsiella pneumoniae isolated from patients in a certain hospital and provide a basis for the rational use of antibiotics in the clinical treatment for the infection of Klebsiella pneumoniae.Methods:1,192 strains of Klebsiella pneumoniae isolated from clinical specimens from 2012 to 2016 were collected.The strains were identified by VITEK-2 Compact Microbiological Identification System,and the corresponding results of the antimicrobial susceptibility test were interpreted in accordance with the standards recommended by Clinical and Laboratory Standards Institute(CLSI).Results:1,192 strains of Klebsiella pneumoniae were mainly isolated from sputum(65.6%),and most of them were from Respiratory Medicine Department and Medical Intensive Care Unit of Respiratory Medicine Department(MICU),accounting for 41.4%.Out of 1,192 strains,448 strains were detected to produce extended-spectrum beta-lactamases(ESBLs),accounting for 37.6%.In addition,the detection rates of ESBL-producing Klebsiella pneumoniae for 5 consecutive years showed an increasing trend year by year,and they were higher than the national average values published by China Antimicrobial Resistance Surveillance System(CARSS)in the corresponding period.The drug resistance rate of ESBL-producing Klebsiella pneumoniae was significantly higher than that of non ESBL-producing strains.Conclusions:The infection caused by Klebsiella pneumoniae mainly occurs in the lower respiratory tract,and the drug resistance rates of Klebsiella pneumoniae to antibiotics in the drug susceptibility spectrum are maintained at a high level.Therefore,the rational selection of antibiotics for the clinical treatment of lower respiratory tract infection caused by Klebsiella pneumoniae must be based on the production of ESBLs and the results of antimicrobial susceptibility test.

Drug repurposing screen identifies vidofludimus calcium and pyrazofurin as novel chemical entities for the development of hepatitis E interventions

Hepatitis E virus(HEV)infection can cause severe complications and high mortality,particularly in pregnant women,organ transplant recipients,individuals with pre-existing liver disease and immunosuppressed patients.However,there are still unmet needs for treating chronic HEV infections.Herein,we screened a best-in-class drug repurposing library consisting of 262 drugs/compounds.Upon screening,we identified vidofludimus calcium and pyrazofurin as novel anti-HEV entities.Vidofludimus calcium is the next-generation dihydroorotate dehydrogenase(DHODH)inhibitor in the phase 3 pipeline to treat autoimmune diseases or SARS-CoV-2 infection.Pyrazofurin selectively targets uridine monophosphate synthetase(UMPS).Their anti-HEV effects were further investigated in a range of cell culture models and human liver organoids models with wild type HEV strains and ribavirin treatment failure-associated HEV strains.Encouragingly,both drugs exhibited a sizeable therapeutic window against HEV.For instance,the IC50 value of vidofludimus calcium is 4.6–7.6-fold lower than the current therapeutic doses in patients.Mechanistically,their anti-HEV mode of action depends on the blockage of pyrimidine synthesis.Notably,two drugs robustly inhibited ribavirin treatment failure-associated HEV mutants(Y1320H,G1634R).Their combination with IFN-αresulted in synergistic antiviral activity.In conclusion,we identified vidofludimus calcium and pyrazofurin as potent candidates for the treatment of HEV infections.Based on their antiviral potency,and also the favorable safety profile identified in clinical studies,our study supports the initiation of clinical studies to repurpose these drugs for treating chronic hepatitis E.

One-step hydrothermal synthesis of Cit-NaYbF_(4):Er^(3+)nanocrystals with enhanced red upconversion emission for in vivo fluorescence molecular tomography

Fluorescence imaging techniques represent essential tools in in vitro,preclinical,and clinical studies.In this study,an improved one-step hydrothermal method to synthesize citric acid(CA)modifiedα-NaYbF_(4):2%Er^(3+)nanocrystals was proposed.The introduction of various doping ions into NaYbF_(4):2%Er^(3+)and the different valence states of the same ions affect both the crystal size and upconversion luminesce nce.There fore,we investigated the upconversion luminesce nce enha ncement of NaYbF_(4):2%Er^(3+)by ion doping and find that the upconversion luminescence intensity of the upconversion nanoparticles(UCNPs)co-doped with 5 mol%Fe^(2+)ions shows the greatest enhancement,especially for red emission at654 nm.Furthermore,HeLa cells incubated with UCNPs allow for imaging with strong red upconversion emission detectio n.Confocal laser scanning microscope(CLSM)fluorescent images of HeLa cells indicate that NaYbF_(4):2%Er/5%Fe^(2+)leads to a clear outline and improves visualization of the cell morphology.In addition,the CA coated NaYbF_(4):2%Er^(3+)/5%Fe^(2+)nanoparticles and NaYbF_(4):2%Er^(3+)/5%Fe^(2+)show low cytotoxicity in HeLa cells.Organ imaging reveals the efficiency of these UCNPs to analyze the lungs,liver,and spleen.Together,these results indicate that the Cit-NaYbF_(4):2%Er^(3+)/5%Fe^(2+)UCNPs are efficient nanoprobes for fluorescence molecular to mography.

CMAS-phobic and infiltration-inhibiting protective layer material for thermal barrier coatings

Calcium-magnesium-alumina-silicate(CMAS)corrosion has attracted special attention in the thermal barrier coating(TBC)field.At high temperatures,when CMAS melts,it adheres to the coating surface and penetrates the interior,severely destroying the TBC.In this study,a promising CMAS-phobic and infiltration-inhibiting material,GdPO4,on which molten CMAs is difficult to wet and penetrate,was proposed.These desirable attributes are explained by analyzing the material characteristics of GdPO_(4) and its interfacial reaction with CMAS.GdPO4 is demonstrated to have low surface energy,making it difficult for molten CMAS to wet and adhere to the surface.When in contact with molten CMAS,a double-layer structured reaction layer consisting of an acicular upper sublayer and a compact lower sublayer is formed on the GdPO4 surface,which can effectively impede molten CMAS spreading and penetration.First-principles calculation results revealed that the reaction layer has low surface energy and low adhesion to CMAS,which are favorable for molten CMAS phobicity.Additionally,the formation of the reaction layer increases the viscosity of the molten CMAS,which can increase melt wetting and penetration.Hence,GdPO4,which exhibits excellent CMAS-phobicity and infiltration-inhibiting ability,is a promising protective layer material for TBCs against CMAS adhesion and attack.

Mechanical properties,thermophysical properties and electronic structure of Yb^(3+)or Ce^(4+)-doped La_(2)Zr_(2)O_(7)-based TBCs

First-principles calculations based on density functional theory were perfo rmed to investigate the cohesive energies,elastic modulus,Debye temperatures,thermal conductivities and density of states of La_(2-x)Yb_(x)Zr_(2)O_(7),La_(2)Zr_(2-x)Ce_(x)O_(7)and La_(2-x)Yb_(x)Zr_(2-x)Ce_(x)O_(7)(x=0.00,0.25,0.50,0.75,1.00)ceramics.The results show that doping Yb~(3+)or Ce~(4+)into La_(2)Zr_(2)O_(7)reduces its elastic modulus,thermal conductivity and Debye temperature.Compared with La_(2-x)Yb_(x)Zr_(2)O_(7)(x≠0.00),La_(2)Zr_(2-x)Ce_(x)O_(7)compounds have better ductility and lower Debye te mperature.The Debye temperature values of La_(2)Zr_(2-x)Ce_(x)O_(7)(x≠0.00)co mpounds are in the range of 485.0-511.5 K.Among all components,the fluorite-type La_(2-x)Yb_(x)Zr_(2-x)Ce_(x)O_(7)(x=0.75,1.00)compounds exhibit better mechanical and thermophysical properties,and their thermal conductivity values are only 1.213-1.246 W/(m·K)(1073 K),which are 14.5%-16.7%lower than that of the pure La_(2)Zr_(2)O_(7).Thus,our findings open an entirely new avenue for TBCs.

Seed nutrient is more stable than leaf in response to changing multiple resources in an alpine meadow

Background It has been long thought that nitrogen(N),phosphorus(P)concentrations and their ratios(N:P)in metabolically active or functional organs(i.e.,leaves)are less responsive to environmental changes.Little attention,however,has been paid to the reproductive organs-seeds,while seeds may maintain their nutrients more stable for the evolutionary fitness of next generation.Methods Here,we conducted a field experiment of N,P addition and drought in an alpine meadow,aiming to compare the difference of leaf and seed nutrients and stoichiometric ratios in response to these resource treatments and their interactions.Four dominant species were selected among grass and forb functional groups,including Elymus nutans,Deschampsia caespitosa,Artemisia roxburghiana and Polygonum viviparum.Results Under natural conditions,leaf N and P concentrations were consistently lower than seed among species.However,leaf nutrients were much more sensitive than seed nutrients to N and P addition.Specifically,N or P addition accordingly increased leaf N or P concentration by 22.20-44.24%and 85.54-93.61%,while only enhanced seed N or P concentration by 5.15-17.20%and 15.17-32.72%,respectively.Leaf N or P concentration was significantly reduced by P or N addition,but seed nutrients remained unchanged.In contrast,drought did not change both organ nutrients.Similarly,nutrient addition and drought had synergistic interactions on leaf nutrients,but not on seed nutrients.Conclusions This study highlights that seed nutrient concentrations could be more stable than metabolically active leaf organ when facing multidimensional resource changes.This complements the traditional view on the‘Stable Leaf Nutrient Hypothesis’with the involvement of reproductive organs.The less responsiveness of seed nutrients suggests the adaptive strategy to ensure the success of next generations and long-term plant demographic stability.

A comprehensive study on the oxidation behavior and failure mechanism of(γ’+β)two-phase Ni-34Al-0.1Dy coating treated by laser shock processing

Laser shock processing(LSP),as a novel surface modification technology,exhibits tremendous potential to improve the oxidation resistance of alloys.In this paper,(γ’+β)two-phase Ni-34Al-0.1Dy coatings were prepared by electron beam physical vapor deposition(EB-PVD)and then treated by LSP with different pulse energy(4 and 5 J).Their oxidation behavior(including isothermal oxidation and cyclic oxidation)at 1150°C was compared.In the isothermal oxidation case,the LSP-treated samples exhibited good ox-idation resistance due to high dislocation density and refined grains caused by the LSP.For the cyclic oxidation,however,the LSP-treated samples were subjected to undesirable thermally grown oxide(TGO)spallation.In the early oxidation stage(within 30 min),the residual compressive stress introduced by the LSP rapidly released,resulting in a severe plastic deformation at the coating/TGO interface.As a result,the mismatch between coating and TGO gave rise to the TGO spallation.With the increase in the oxida-tion time,work hardening,which continuously limited the synchronous deformation of the TGO/coating interface,became the dominant mechanism controlling the TGO spallation of 5 J-treated coatings.The continuous TGO spallation affected the Al supply and thus deteriorated the cyclic oxidation behavior.

Microstructure and high-temperature oxidation behavior of plasma-sprayed Si/Yb2SiO5 environmental barrier coatings

An environmental barrier coating(EBC) consisting of a silicon bond coat and an Yb2-SiO5 top-coat was sprayed on a carbon fibers reinforced SiC ceramic matrix composite(CMC) by atmospheric plasma spray(APS). The microstructure of the coating annealed at 1300 ℃ and its high-temperature oxidation behavior at 1350 ℃ were investigated. The significant mass loss of silica during the plasma spray process led to the formation of Yb2SiO5 and Yb2O3 binary phases in the top-coat. Eutectics of Yb2SiO5 and Yb2O3 were precipitated in the top-coat, and channel cracks were formed in the top-coat after 20 h annealing because of the mismatch between the coefficients of thermal expansion(CTEs) of Yb2SiO5 and the SiC substrate. The EBC effectively improved the oxidation resistance of the CMC substrate. The channel cracks in the Yb2SiO5 top-coat provided inward diffusion channels for oxygen and led to the formation of oxidation delamination cracks in the bond coat, finally resulting in spallation failure of the coating after 80 h oxidation.

Impermeability of Y_3Al_5O_(12) ceramic against molten glassy calcium-magnesium-alumina-silicate

Degradation of thermal barrier coatings(TBCs) caused by calcium-magnesium-aluminasilica(CMAS) glassy penetration is becoming an urgent issue for TBCs industrial applications. In this work, yttrium aluminum garnet(YAlO, YAG) nano-powders were synthesized through a chemical co-precipitation route. The resistance of YAG ceramic to glassy CMAS infiltration at1250 °C was evaluated. YAG ceramic bulk sintered at 1700 °C for 10 h was comprised of a single garnet-type YAlOphase. The molten CMAS glass was suppressed on the surface of the YAG ceramic at 1250 °C. A chemical reaction between YAG and the molten CMAS glass did not occur at 1250 °C for 24 h, suggesting that YAG could act as an impermeable material against glassy CMAS deposits in the TBC field.

Effects of rare earth oxides on microstructures and thermo-physical properties of hafnia ceramics

Rare earth oxides doped hafnia ceramics,with a formula of Hf0.76LnxY0.24-xO1.88(Ln=Gd,Yb,Gd+Yb or La+Yb),were prepared by solid state sintering at 1500℃.The effects of the rare earth oxides on the microstructures,sintering resistance,and thermo-physical properties of the doped hafnia ceramics were investigated.Results show that the Gd-Y,Yb-Y or Gd-Yb-Y co-doped hafnia ceramics remain the same defect fluorite(F)structure,while the La-Yb-Y co-doped hafnia revealing coexistence of pyrochlore(P)and fluorite structures.Yb-Y co-doped samples exhibited much better sintering resistance compared with Gd-Y and Gd-Yb-Y co-doped samples.The coexistence of P and F phases is beneficial to improved sintering capability.The thermal conductivities of the Gd-Y,Yb-Y and Gd-Yb-Y doped samples are relatively lower(1.4-1.7 W m^(-1)K^(-1)at 1200℃),but for the La-Yb-Y co-doped samples,the thermal conductivity increases dramatically with temperature due to increased thermal radiation at high-temperature.The average thermal expansion coefficients(TECs)of the Gd-Y,Yb-Y and Gd-Yb-Y co-doped samples are as high as10.3×10^(-6)K^(-1) in temperature range between 200-1200℃.

Substituent position effect of Co porphyrin on oxygen electrocatalysis

Substituent effect of metal porphyrin molecular catalysts plays a crucial role in determining the catalytic activity of oxygen electrocatalysis.Herein,substituent position effect of Co porphyrins on oxygen electrocatalysis,including the oxygen reduction reaction(ORR)and the oxygen evolution reaction(OER),was investigated.Two Co porphyrins,namely 2,4,6-OMe-CoP and 3,4,5-OMe-CoP,were selected as the research objects.The ORR and OER performance was evaluated by drop-coating molecular catalysts on carbon nanotubes(CNTs).The resulted 3,4,5-OMe-CoP/CNT exhibited high bifunctional electrocatalytic activities and better long-term stability for both ORR and OER than 2,4,6-OMe-CoP/CNT.Furthermore,when applied in the Zn-air battery,3,4,5-OMe-CoP/CNT exhibited comparable performance to that with precious metal-based materials.The enhanced catalytic activity may be attributed to the improved charge transfer rate,mass transfer and hydrophilicity.This work provides an effective strategy to further enhance catalytic activity by introducing substituent position effect,which is of great importance for developing more efficient energy-related electrocatalysts.

The role of Re in improving the oxidation-resistance of a Re modified PtAl coating on Mo-rich single crystal superalloy

A novel Re modifiedβ-(Ni,Pt)Al coating was prepared on a Mo-rich Ni_3 Al-based single crystal(SC)superalloy by electro-deposition of Re/Pt dual films and low-activity aluminizing.The isothermal oxidation behavior of the Re modifiedβ-(Ni,Pt)Al coating and traditionalβ-(Ni,Pt)Al coating was comparatively studied at 1100℃.Apparent spallation of oxide scale was found on the surface of traditionalβ-(Ni,Pt)Al coating after 300 h isothermal exposure,which mainly resulted from the evaporation of Mo-containing oxides.It is further found that the outward diffusion of Mo from the SC substrate was effectively inhibited in the Re modifiedβ-(Ni,Pt)Al coating by forming theσ-MoRe phase both at the coating/superalloy interface and grain boundaries.It is also revealed that the addition of Re can stabilise Mo to form theσ-MoRe phase,allowing the improved oxidation resistance of the Re modifiedβ-(Ni,Pt)Al coating.