This paper investigated the effects of root-zone (RZ) CO<sub>2</sub> concentration ([CO<sub>2</sub>]) on root morphology and growth, nitrate (NO<sub>3</sub>-</sup>) uptake and...This paper investigated the effects of root-zone (RZ) CO<sub>2</sub> concentration ([CO<sub>2</sub>]) on root morphology and growth, nitrate (NO<sub>3</sub>-</sup>) uptake and assimilation of lettuce plants at different root-zone temperatures (RZT). Elevated RZ [CO<sub>2</sub>] stimulated root development, root and shoot growth compared to ambient RZ [CO<sub>2</sub>]. The greatest increase in root growth was observed in plants grown under elevated RZ [CO<sub>2</sub>] of 50,000 ppm. However, RZ [CO<sub>2</sub>] of 10,000 ppm was sufficient to achieve the maximal leaf area and shoot productivity. Lettuce plants exhibited faster shoot and root growth at 20°C-RZT than at ambient (A)-RZT. However, under elevated RZ [CO<sub>2</sub>], the magnitude of increased growth was greater at A-RZT than at 20°C-RZT. Compared to RZ [CO<sub>2</sub>] of 360 ppm, elevated RZ [CO<sub>2</sub>] of 10,000 ppm increased NO<sub>3</sub>-</sup> accumulation and nitrate reductase activity (NRA) in both leaves and roots. NO<sub>3</sub>-</sup> concentrations of leaf and root were higher at 20°C-RZT than at A-RZT in all plants. NRA was higher in root than in leaf especially under A-RZT. The total reduced nitrogen (TRN) concentration was significantly higher in plants grown under elevated RZ [CO<sub>2</sub>] of 10,000 ppm than under ambient RZ [CO<sub>2</sub>] of 360 ppm with greater concentration in 20°C-RZT plants than in A-RZT plants. These results imply that elevated RZ [CO<sub>2</sub>] significantly affected root morphology, root and shoot growth and N metabolism of temperate lettuce with greater impacts at A-RZT than at 20°C-RZT. These findings have practical significance to vegetable production by growing the vegetable crops at cool-RZT with elevated RZ [CO<sub>2</sub>] to enhance its productivity.展开更多
Wastewater electrolysis cells(WECs)for decentralized wastewater treatment/reuse coupled with H_(2) production can reduce the carbon footprint associated with transportation of water,waste,and energy carrier.This study...Wastewater electrolysis cells(WECs)for decentralized wastewater treatment/reuse coupled with H_(2) production can reduce the carbon footprint associated with transportation of water,waste,and energy carrier.This study reports Ir-doped NiFe_(2)O_(4)(NFI,~5 at%Ir)spinel layer with TiO_(2) overlayer(NFI/TiO_(2)),as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell.In dilute(0.1 M)NaCl solutions,the NFI/TiO_(2) marks superior activity and selectivity for chlorine evolution reaction,outperforming the benchmark IrO_(2).Robust operation in near-neutral pH was confirmed.Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO_(2) which serves both as the primary site for Cl−chemisorption and a protective layer for NFI as an ohmic contact.Galvanostatic electrolysis of NH4+-laden synthetic wastewater demonstrated that NFI/TiO_(2)not only achieves quasi-stoichiometric NH_(4)^(+)-to-N_(2)conversion,but also enhances H_(2)generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine.The scaled-up WEC with NFI/TiO_(2)was demonstrated for electrolysis of toilet wastewater.展开更多
The ablation debris and raised rim, as well as residual stress and deep crater will be formed during the mitigation of damage site with a CO2 laser irradiation on fused silica surface, which greatly affects the laser ...The ablation debris and raised rim, as well as residual stress and deep crater will be formed during the mitigation of damage site with a CO2 laser irradiation on fused silica surface, which greatly affects the laser damage resistance of optics. In this study, the experimental study combined with numerical simulation is utilized to investigate the effect of the secondary treatment on a mitigated site by CO2laser irradiation. The results indicate that the ablation debris and the raised rim can be completely eliminated and the depth of crater can be reduced. Notable results show that the residual stress of the mitigation site after treatment will reduce two-thirds of the original stress. Finally, the elimination and the controlling mechanism of secondary treatment on the debris and raised rim, as well as the reasons for changing the profile and stress are analyzed. The results can provide a reference for the optimization treatment of mitigation sites by CO2laser secondary treatment.展开更多
BACKGROUND The preservation of isletβ-cell function in elderly patients with type 2 diabetes mellitus(T2DM)is a top priority for diabetic control.AIM To assess the preservation of isletβ-cell function among elderly ...BACKGROUND The preservation of isletβ-cell function in elderly patients with type 2 diabetes mellitus(T2DM)is a top priority for diabetic control.AIM To assess the preservation of isletβ-cell function among elderly Chinese patients with T2DM after different anti-diabetic treatments.METHODS In this longitudinal observational study,elderly patients with T2DM treated with insulin,oral antidiabetic drugs or a combination of both were enrolled to disclose their isletβ-cell function between baseline and follow-up.Isletβ-cell function was determined by the plasma Homeostasis Model forβ-cell function(HOMA-β),Cpeptide and area under the curve(AUC)based on oral glucose tolerance test.Changes inβ-cell function(decrement or increment from baseline)between different therapy groups were the outcomes.RESULTS In total,745 elderly patients(≥60 years)with T2DM[insulin monotherapy,n=105;oral anti-diabetic drugs(OAD)monotherapy,n=321;insulin plus OAD,n=319]had their baseline and follow-upβ-cell function assessed during a median observation period of 4.5 years(range,3.0-7.2 years).Overall,isletβ-cell function(HOMA-β,fasting Cpeptide,fasting insulin,AUCc-pep,AUCins,AUCc-pep/AUCglu,AUCins/AUCglu)consistently deteriorated over time regardless of the three different antidiabetic treatments.No statistical differences in decrement were observed among the three groups regarding the isletβ-cell function indices.All three groups showed an increased ratio of delayed insulin secretion response after 4.5 years of observation.CONCLUSION In Chinese elderly patients with T2DM,isletβ-cell function progressively declines regardless of insulin supplement or insulin plus OAD treatments.展开更多
The development of efficient low-load platinum catalysts for CO oxidation is critical for large-scale industrial applications and environmental protection.In this study,a strategy of N_(2)treatment triggered the self-...The development of efficient low-load platinum catalysts for CO oxidation is critical for large-scale industrial applications and environmental protection.In this study,a strategy of N_(2)treatment triggered the self-reforming into fully exposed Pt cluster catalysts was proposed.By adjusting the coordination environment of Pt species on the defect support through N_(2)treatment,the CO catalytic activity was significantly enhanced,achieving complete CO oxidation at 130℃with a Pt loading of only 0.1 wt.%.The turnover frequency of N_(2)-treated Pt_(FEC)/Ti-D at 160℃was 18.3 times that of untreated Pt_(SA)/Ti-D.Comprehensive characterization results indicated that the N_(2)treatment of the Pt single-atom defect catalyst facilitated the reconfiguration and evolution of the defect structure,leading to the aggregation of Pt single atoms into fully exposed Pt clusters.Notably,these fully exposed Pt clusters exhibited a reduced coordination of Pt–O in the first coordination shell compared to single atoms,which resulted in the formation of Pt–Pt metal coordination.This unique coordination structure enhanced the adsorption and activation of CO and O_(2)on the catalyst,thereby resulting in exceptionally low-temperature CO oxidation activity.This work demonstrates a promising strategy for the design,synthesis,and industrial application of efficient low-platinum load catalysts.展开更多
Objective To investigate the therapeutic efficacy and potential mechanisms of fecal microbiota transplantation(FMT)in patients with type 2 diabetes mellitus(T2DM),and to preliminarily identify the traditional Chinese ...Objective To investigate the therapeutic efficacy and potential mechanisms of fecal microbiota transplantation(FMT)in patients with type 2 diabetes mellitus(T2DM),and to preliminarily identify the traditional Chinese medicine(TCM)syndrome element characteristics of FMT in the treatment of T2DM.Methods Between March 25,2023 and September 30,2024,T2DM patients who met the inclusion and exclusion criteria were enrolled at the Department of Rheumatology and Endocrinology of the Second Affiliated Hospital of Fujian University of Traditional Chinese Medicine.Participants received oral microbiota capsules as an adjunct to metformin therapy.Information obtained by four diagnostic methods of TCM,along with clinical and laboratory parameters,was collected before and after the intervention.Metagenomic sequencing was employed to analyze the gut microbiota,and Spearman correlation analysis was used to explore the relationship between laboratory indicators and differential bacterial genera.According to the post-treatment reduction in glycosylated hemoglobin(HbA1c),patients were categorized into a response(R)group and a non-response(NR)group.Treatment outcomes,safety indicators,gut microbiota changes,and TCM syndrome element features were compared between the two groups.Results A total of 53 T2DM patients were included in the final analysis,and 30 patients were assigned to R group and 23 to NR group.After treatment,the R group exhibited significant reductions in HbA1c,fasting plasma glucose(FPG),and 2-hour postprandial glucose(2hPG)(P<0.05 or P<0.01).The NR group also showed significant decreases in HbA1c and FPG levels P<0.01 or P<0.05.Compared with the NR group,after treatment,FPG level in the R group demonstrated significant reductions(P<0.01).As compared with before treatment,pancreatic islet function demonstrated enhancement in the R group,a significant increase in the 2-hour pastprandial C-peptide(2hC-P)levels in R group(P<0.05),whereas no marked change was observed in the NR group.Regarding body composition indicators,the R group showed significantly lower waist-hip ratio(WHR),visceral fat(VF),and subcutaneous fat(SF)levels compared with the NR group(P<0.01).After treatment,the NR group exhibited a significant elevation in aspartate aminotransferase(AST)levels(P<0.05).Other safety-related indicators fluctuated within normal reference ranges,and no other adverse events,such as diarrhea,fever,or nausea,were reported.Metagenomic sequencing showed that FMT improved the diversity and richness of the gut microbiota,remodeling its overall structure.At the phylum level,the abundance of p_Firmicutes decreased significantly(P<0.01),while the abundances of p_Bacteroidota and p_Proteobacteria increased significantly(P<0.01).At the family level,among the 125 identified taxa,the abundances of f_Bacteroidaceae,f_Lactobacillaceae,and f_Sutterellaceae were significantly elevated,whereas six families,including f_Lachnospiraceae,f_Ruminococcaceae,and f_Coriobacteriaceae,were significantly decreased(all P<0.05).Among the 367 taxa at the genus level,the top 10 differential genera showed significantly increased abundances of g_Bacteroides and g_Sutterella,and significantly decreased abundances in eight genera,including g_Faecalibacterium,g_Ruminococcus,g_Blautia,and g_Collinsella(all P<0.05).Correlation analysis suggested that the phylum p_Bacillota was positively correlated with improvements in T2DM laboratory parameters,g_norank_f_Prevotellaceae was significantly positively correlated with fasting C-peptide(FC-P)and 2hC-P(P<0.05).HbA1c demonstrated a significantly positive correlation with g_Blautia and g_Gemmiger(P<0.05)and a significantly negative correlation with g_Bacteroides and g_Collinsella(P>0.05).Analysis of syndrome element characteristics revealed that the R group was primarily characterized by pathological patterns of dampness,phlegm,and Yang deficiency.Before treatment,statistically significant reductions in syndrome element scores were observed for dampness,Yang deficiency,spleen,phlegm,Qi deficiency,Qi stagnation,and Yin deficiency(P<0.01),as well as for heat and liver(P<0.05).The NR group was mainly featured with Qi deficiency and Yin deficiency.Statistically significant changes in their syndrome element scores after treatment were noted for Qi deficiency(P<0.01),and for spleen,Qi stagnation,liver,and blood deficiency(P<0.05).In this group,the score changes for Yang deficiency,Yin deficiency,heat,and dampness were not statistically significant(P>0.05).Conclusion The principles of syndrome element differentiation can be effectively applied to predict treatment efficacy and facilitate patient selection for FMT in the treatment of T2DM.Patients with T2DM presented with specific TCM syndrome element characteristics,notably dampness,phlegm,and Yang deficiency,represent a highly responsive population to FMT therapy.展开更多
Diffusion-bonded Ti_(2)AlNb-based alloys commonly present a low strength compared with the deformed or aged ones. In this study, the post heat treatment including solution and aging treatments is proposed to optimize ...Diffusion-bonded Ti_(2)AlNb-based alloys commonly present a low strength compared with the deformed or aged ones. In this study, the post heat treatment including solution and aging treatments is proposed to optimize the microstructure, contributing to strength improvement and appropriate ductility sacrifice. An available method by the introduction of fine size (both 20-100 nm) and a high fraction (59.7% and 13.7%) of O and α_(2) phases using both solution at 1000℃ for 1 h and aging at 750℃ for 5 h can result in excellent tensile strength (992 MPa and 858 MPa) at room temperature and 650℃, respectively, which increases 5.3% and 44.5% than that of as-received sample. The aging treatment can contribute to lamellar O and α2 grains precipitated from the B_(2) parent, which results in limited dislocation slip systems and slip spaces to resist plastic deformation. Moreover, the crack propagation and fracture surfaces are also comparatively analyzed to reveal the fracture behaviors in the samples with high and low strength. This study can provide a new method for the mechanical property optimization of the welded Ti_(2)AlNb alloys.展开更多
Formaldehyde(HCHO)is a significant indoor pollutant found in various sources and poses potential health risks to humans.Noble metal catalysts show efficient and stable catalytic activity for ambient-temperature HCHO o...Formaldehyde(HCHO)is a significant indoor pollutant found in various sources and poses potential health risks to humans.Noble metal catalysts show efficient and stable catalytic activity for ambient-temperature HCHO oxidation,yet suffer from low metal utilization.Efforts focus on designing catalysts with enhanced intrinsic activity and reduced noble metal loading.In this study,we developed a simple pretreatment method using ammonia solution on SiO_(2)carrier to enhance the activity of the Pd/SiO_(2)catalyst for HCHO oxidation.After the carrier was pretreated with an ammonia solution,a significant promoting effect was observed on the Pd/SiO_(2)(NH_(3)·H_(2)O)-R catalyst.It achieved almost complete oxidation of 150 ppmV of HCHO at 25℃,much better than the Pd/SiO_(2)-R(5%HCHO conversion rate).Multiple characterization results indicated that the ammonia solution pretreatment of the SiO_(2)carrier increased the surface defects,facilitating the anchoring of Pd nanoparticles and increasing their dispersion.The increase dispersion of Pd resulted in the generation of additional oxygen vacancies on the catalyst surfaces.The increased in oxygen vacancies on the catalyst was beneficial for enhancing the catalyst's ability to activate H_(2)O to form surface hydroxyl groups,thereby accelerating the catalytic oxidation process of HCHO.The reaction mechanism of HCHO on the Pd/SiO_(2)(NH_(3)·H_(2)O)-R catalyst mainly follows an efficient pathway:firstly,the HCHO being oxidized by surface active hydroxyl groups to formate;subsequently,the formate being oxidized by hydroxyl groups to H_(2)O and CO_(2).This study provides a promising strategy for designing high-performance noble metal catalysts for HCHO catalytic oxidation.展开更多
BACKGROUND Gastric cancer is one of the most common malignant tumors worldwide,with its incidence and mortality rates ranking among the highest in gastrointestinal cancers.The overexpression or gene amplification of h...BACKGROUND Gastric cancer is one of the most common malignant tumors worldwide,with its incidence and mortality rates ranking among the highest in gastrointestinal cancers.The overexpression or gene amplification of human epidermal growth factor receptor 2(HER-2)occurs in approximately 15%-20%of gastric cancers and serves as a critical molecular target influencing prognosis and treatment out-comes.For patients with HER-2-positive gastric cancer,trastuzumab combined with platinum-based chemotherapy has been established as the standard first-line treatment.However,despite the demonstrated clinical benefits in prolonging survival,the overall efficacy remains limited.In recent years,with the successful application of immune checkpoint inhibitors(ICIs)in various malignant tumors,combining ICIs with existing standard treatment regimens has emerged as a promising approach to enhance the therapeutic efficacy of HER-2-positive gastric cancer.Nevertheless,the efficacy and prognostic factors of ICIs combined with trastuzumab and chemotherapy in HER-2-positive gastric cancer remain unclear.AIM To analyze the efficacy of ICIs combined with standard treatment regimens and the prognostic factors in patients with advanced HER-2-positive gastric cancer.METHODS Clinical data from 104 patients with advanced HER-2-positive gastric cancer who were treated at our hospital between March 2021 and May 2023 were retrospectively analyzed.Patients were divided into a control group(n=54,treated with trastuzumab combined with platinum-based chemotherapy as the standard regimen)and an observation group(n=50,treated with ICIs in addition to the standard regimen).The therapeutic efficacy,survival outcomes,and adverse reactions were compared between the two groups.Univariate and Cox multivariate analyses were performed to identify factors influencing patient prognosis.RESULTS With a median follow-up time of 14.6 months,there were no significant differences between the two groups in terms of objective response rate or disease control rate(P>0.05).The median progression-free survival(mPFS)and mPFS for patients with immunohistochemistry 3+in the observation group were significantly higher than those in the control group(P<0.05).Among patients in the observation group,those with positive programmed death-ligand 1(PD-L1)expression had a significantly higher mPFS than those with negative PD-L1 expression(P<0.05).Regarding adverse events,significant differences were observed between the two groups in hypothyroidism and neutropenia(P<0.05).Cox multivariate analysis showed that Eastern Cooperative Oncology Group(ECOG)performance status,peritoneal metastasis,positive programmed death-1 expression,and treatment regimen were independent factors influencing PFS(hazard ratio>1,P<0.05).CONCLUSION ICIs combined with standard treatment regimens for patients with advanced HER-2-positive gastric cancer demonstrate favorable clinical efficacy,significantly prolonging PFS with manageable safety.ECOG performance status,peritoneal metastasis,positive PD-L1 expression,and treatment regimen are independent factors influ-encing PFS,warranting increased clinical attention to patients exhibiting these factors.展开更多
The pressing demand for ultrathin and flexible shields to counter electromagnetic interference(EMI)has sparked interest in Ti_(3)C_(2)T_(x)MXene materials due to their exceptional electrical conductivity,tunable surfa...The pressing demand for ultrathin and flexible shields to counter electromagnetic interference(EMI)has sparked interest in Ti_(3)C_(2)T_(x)MXene materials due to their exceptional electrical conductivity,tunable surface chemistry,and layered structure.However,pure Ti_(3)C_(2)T_(x)MXene films often lack the mechanical properties required for practical engineering applications,and traditional reinforcement methods tend to reduce electrical conductivity.This work demonstrates an effective strategy to enhance the alignment and densely packed layered structure of Ti_(3)C_(2)T_(x)MXene films by regulating the acidity and alkalinity of Ti_(3)C_(2)T_(x)MXene aqueous solutions.This approach simultaneously improves mechanical strength and electromagnetic interference shielding effectiveness(EMI SE).Compared with original Ti_(3)C_(2)T_(x)MXene films,MXene films modified with ammonia solution(NH_(3)·H_(2)O)via OH-show a significant improvement in tensile strength(27.7±1.9 MPa).Meanwhile,MXene films treated with hydrochloric acid(HCl)via H^(+)reach an even higher tensile strength of 39±1.5 MPa.Moreover,the EMI SE values of the treated MXene films increase significantly,each reaching 66.2 and 58.4 dB.The maximum improvements in EMI SE values for the acid-and alkali-treated samples are 17.9%and 4%,respectively.In conclusion,the simultaneous enhancement of mechanical strength and EMI shielding efficacy highlights the potential of acid-and alkali-treated Ti_(3)C_(2)T_(x)MXene films for applications in ultrathin and flexible EMI shielding materials.展开更多
Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received wides...Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices.During bipolar high electric-field cycling in numbers close to dielectric breakdown,the dielectric permittivity suddenly increases by 30 times after oxygen-vacancy ordering and ferroelectric-to-nonferroelectric phase transition of near-edge plasma-treated Hf_(0.5)Zr_(0.5)O_(2) thin-film capacitors.Here we report a much higher dielectric permittivity of 1466 during downscaling of the capacitor into the diameter of 3.85μm when the ferroelectricity suddenly disappears without high-field cycling.The stored charge density is as high as 183μC cm^(−2) at an operating voltage/time of 1.2 V/50 ns at cycle numbers of more than 10^(12) without inducing dielectric breakdown.The study of synchrotron X-ray micro-diffraction patterns show missing of a mixed tetragonal phase.The image of electron energy loss spectroscopy shows the preferred oxygen-vacancy accumulation at the regions near top/bottom electrodes as well as grain boundaries.The ultrahigh dielectric-permittivity material enables high-density integration of extremely scaled logic and memory devices in the future.展开更多
2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al...2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al） matrix of 2A97 alloy processed by the heat treatment with no pre-stretch deformation. When the pre-stretch deformation is 3% and 6%, respectively, amounts of tiny T1 and a few of S＇ precipitates precipitates are observed in the microstructures of 2A97 alloy. The tensile test results show that the tensile properties of 2A97 alloys are improved via thermo-mechanical treatment. When the pre-stretch deformation is from 0, 3% to 6%, the ultimate tensile strength values of the 2A97 alloys increase gradually from 447.7, 516.5 to 534.3 MPa, and the elongations decrease from 17.6%, 12.8% to 10.2%, respectively. Moreover, with increasing pre-stretch deformation amount from 0 to 6%, the in-plane anisotropy value of 2A97 alloys becomes more obvious.展开更多
Influence of heat treatment on the microstructures and mechanical properties of sand-cast Mg-4Y-2Nd-1Gd-0.4Zr magnesium alloy was investigated,and the tensile fracture mechanisms of the studied alloys under different ...Influence of heat treatment on the microstructures and mechanical properties of sand-cast Mg-4Y-2Nd-1Gd-0.4Zr magnesium alloy was investigated,and the tensile fracture mechanisms of the studied alloys under different conditions were also discussed.The results show that the optimum T4 and T6 heat treatment conditions for the as-cast Mg-4Y-2Nd-1Gd-0.4Zr alloy are 525°C,8 h and（525°C,8 h）＋（225°C,16 h）,respectively,with regard to the microstructure observation,DSC heating curve and mechanical properties.The hardness,yield strength,ultimate tensile strength and elongation of the Mg-4Y-2Nd-1Gd-0.4Zr alloy treated by optimum T6 heat treatment are HV91,180 MPa,297 MPa and 7.4%,respectively.Moreover,the Mg-4Y-2Nd-1Gd-0.4Zr alloys under different heat treatment conditions exhibit different tensile fracture modes.展开更多
The influence of solution treatment on the microstructure and properties of Mg2Si/AZ91D composites fabricated from Mg-SiO2 system via in-situ processing method was investigated.The results show that coarse Chinese scr...The influence of solution treatment on the microstructure and properties of Mg2Si/AZ91D composites fabricated from Mg-SiO2 system via in-situ processing method was investigated.The results show that coarse Chinese script shape Mg2Si phases can be formed by adding SiO2 into AZ91D magnesium alloy with Si content up to 1.5% of the alloy melt.During solution treatment,the morphology and distribution of the coarse Chinese script shape Mg2Si phases are modified.Meanwhile,the β-Mg17Al12 phase is dissolved into the magnesium matrix.With increasing holding time,the coarse Mg2Si phases tend to dissolve,break and spheroidize.After solution treatment at 420 ℃ for 16 h,Mg2Si phases become the finest and relatively well-distributed phase.The tensile strength and elongation are increased by 14.9% and 38.9%,respectively.It is believed that the Mg2Si phases continuously dissolve and break,and finally the spheroidized Mg2Si particles are obtained due to the interface tension of Mg2Si/Mg interface.展开更多
The effects of the ultrasonic treatment on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy were investigated. The results show that the ultrasonic treatment has significant effect on the microstr...The effects of the ultrasonic treatment on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy were investigated. The results show that the ultrasonic treatment has significant effect on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy. The phases in Mg-6Zn-0.5Y-2Sn alloy are α-Mg, MgZn2, MgSnY, Mg2Sn, and a small amount of I-phase. With the application of ultrasonic treatment, I-phase nearly disappears, and with increasing the ultrasonic treatment power, the coarse dendrites gradually change into roundish equiaxed grains. The second phases at the α-Mg boundaries transform from coarse, semicontinuous and non-uniform to fine, discontinuous, uniform and dispersive. When the ultrasonic treatment power is 700 W, the best comprehensive mechanical properties of Mg-6Zn-0.5Y-2Sn alloy are obtained. Compared with the untreated alloy, the 0.2%tensile yield strength, ultimate tensile strength and elongation are improved by 28%, 30%and 67%, respectively.展开更多
The microstructures of as-extruded and stabilizing heat-treated Zn-10Al-2Cu-0.02Ti alloys were observed by scanning electron microscopy,transmission electron microscopy,electron probe microanalysis and X-ray diffracti...The microstructures of as-extruded and stabilizing heat-treated Zn-10Al-2Cu-0.02Ti alloys were observed by scanning electron microscopy,transmission electron microscopy,electron probe microanalysis and X-ray diffraction analysis techniques.The change in structure after heat treatment and its effects on room temperature creep behavior were investigated by creep experiments at constant stress and slow strain rate tensile tests.The results show that after stabilizing heat treatment（（350℃,30 min,water-cooling）＋（100℃,12 h,air-cooling））,the amount of α＋η lamellar structure decreases,while the amount of cellular and granular structure increases.The heat-treated Zn-10Al-2Cu-0.02Ti alloy exhibits better creep resistance than the as-extruded alloy,and the rate of steady state creep decreases by 96.9% after stabilizing heat treatment.展开更多
文摘This paper investigated the effects of root-zone (RZ) CO<sub>2</sub> concentration ([CO<sub>2</sub>]) on root morphology and growth, nitrate (NO<sub>3</sub>-</sup>) uptake and assimilation of lettuce plants at different root-zone temperatures (RZT). Elevated RZ [CO<sub>2</sub>] stimulated root development, root and shoot growth compared to ambient RZ [CO<sub>2</sub>]. The greatest increase in root growth was observed in plants grown under elevated RZ [CO<sub>2</sub>] of 50,000 ppm. However, RZ [CO<sub>2</sub>] of 10,000 ppm was sufficient to achieve the maximal leaf area and shoot productivity. Lettuce plants exhibited faster shoot and root growth at 20°C-RZT than at ambient (A)-RZT. However, under elevated RZ [CO<sub>2</sub>], the magnitude of increased growth was greater at A-RZT than at 20°C-RZT. Compared to RZ [CO<sub>2</sub>] of 360 ppm, elevated RZ [CO<sub>2</sub>] of 10,000 ppm increased NO<sub>3</sub>-</sup> accumulation and nitrate reductase activity (NRA) in both leaves and roots. NO<sub>3</sub>-</sup> concentrations of leaf and root were higher at 20°C-RZT than at A-RZT in all plants. NRA was higher in root than in leaf especially under A-RZT. The total reduced nitrogen (TRN) concentration was significantly higher in plants grown under elevated RZ [CO<sub>2</sub>] of 10,000 ppm than under ambient RZ [CO<sub>2</sub>] of 360 ppm with greater concentration in 20°C-RZT plants than in A-RZT plants. These results imply that elevated RZ [CO<sub>2</sub>] significantly affected root morphology, root and shoot growth and N metabolism of temperate lettuce with greater impacts at A-RZT than at 20°C-RZT. These findings have practical significance to vegetable production by growing the vegetable crops at cool-RZT with elevated RZ [CO<sub>2</sub>] to enhance its productivity.
基金supported by the National Research Foundation of Korea(NRF)grants(2022R1A2C4001228,2022M3H4A4097524,2022M3I3A1082499,and 2021M3I3A1084818)the Technology Innovation Program(20026415)of the Ministry of Trade,Industry&Energy(MOTIE,Korea)the supports from Nanopac for fabrication of scaled-up reactor.
文摘Wastewater electrolysis cells(WECs)for decentralized wastewater treatment/reuse coupled with H_(2) production can reduce the carbon footprint associated with transportation of water,waste,and energy carrier.This study reports Ir-doped NiFe_(2)O_(4)(NFI,~5 at%Ir)spinel layer with TiO_(2) overlayer(NFI/TiO_(2)),as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell.In dilute(0.1 M)NaCl solutions,the NFI/TiO_(2) marks superior activity and selectivity for chlorine evolution reaction,outperforming the benchmark IrO_(2).Robust operation in near-neutral pH was confirmed.Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO_(2) which serves both as the primary site for Cl−chemisorption and a protective layer for NFI as an ohmic contact.Galvanostatic electrolysis of NH4+-laden synthetic wastewater demonstrated that NFI/TiO_(2)not only achieves quasi-stoichiometric NH_(4)^(+)-to-N_(2)conversion,but also enhances H_(2)generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine.The scaled-up WEC with NFI/TiO_(2)was demonstrated for electrolysis of toilet wastewater.
基金supported by the National Natural Science Foundation of China(Grant Nos.61505170,61505171,and 51535003)the Joint Fund of the National Natural Science Foundation of China+1 种基金the Chinese Academy of Engineering Physics(Grant No.U1530109)the China Postdoctoral Science Foundation(Grant No.2016M592709)
文摘The ablation debris and raised rim, as well as residual stress and deep crater will be formed during the mitigation of damage site with a CO2 laser irradiation on fused silica surface, which greatly affects the laser damage resistance of optics. In this study, the experimental study combined with numerical simulation is utilized to investigate the effect of the secondary treatment on a mitigated site by CO2laser irradiation. The results indicate that the ablation debris and the raised rim can be completely eliminated and the depth of crater can be reduced. Notable results show that the residual stress of the mitigation site after treatment will reduce two-thirds of the original stress. Finally, the elimination and the controlling mechanism of secondary treatment on the debris and raised rim, as well as the reasons for changing the profile and stress are analyzed. The results can provide a reference for the optimization treatment of mitigation sites by CO2laser secondary treatment.
基金Medical Ethics Committee of the Nanxishan Hospital of Guangxi Zhuang Autonomous Region(Approval No.NXSYY-2024-209).
文摘BACKGROUND The preservation of isletβ-cell function in elderly patients with type 2 diabetes mellitus(T2DM)is a top priority for diabetic control.AIM To assess the preservation of isletβ-cell function among elderly Chinese patients with T2DM after different anti-diabetic treatments.METHODS In this longitudinal observational study,elderly patients with T2DM treated with insulin,oral antidiabetic drugs or a combination of both were enrolled to disclose their isletβ-cell function between baseline and follow-up.Isletβ-cell function was determined by the plasma Homeostasis Model forβ-cell function(HOMA-β),Cpeptide and area under the curve(AUC)based on oral glucose tolerance test.Changes inβ-cell function(decrement or increment from baseline)between different therapy groups were the outcomes.RESULTS In total,745 elderly patients(≥60 years)with T2DM[insulin monotherapy,n=105;oral anti-diabetic drugs(OAD)monotherapy,n=321;insulin plus OAD,n=319]had their baseline and follow-upβ-cell function assessed during a median observation period of 4.5 years(range,3.0-7.2 years).Overall,isletβ-cell function(HOMA-β,fasting Cpeptide,fasting insulin,AUCc-pep,AUCins,AUCc-pep/AUCglu,AUCins/AUCglu)consistently deteriorated over time regardless of the three different antidiabetic treatments.No statistical differences in decrement were observed among the three groups regarding the isletβ-cell function indices.All three groups showed an increased ratio of delayed insulin secretion response after 4.5 years of observation.CONCLUSION In Chinese elderly patients with T2DM,isletβ-cell function progressively declines regardless of insulin supplement or insulin plus OAD treatments.
基金supported by the National Natural Science Foundation of China(52170118,52322004,52230002)the China Postdoctoral Science Foundation(2024M763296).
文摘The development of efficient low-load platinum catalysts for CO oxidation is critical for large-scale industrial applications and environmental protection.In this study,a strategy of N_(2)treatment triggered the self-reforming into fully exposed Pt cluster catalysts was proposed.By adjusting the coordination environment of Pt species on the defect support through N_(2)treatment,the CO catalytic activity was significantly enhanced,achieving complete CO oxidation at 130℃with a Pt loading of only 0.1 wt.%.The turnover frequency of N_(2)-treated Pt_(FEC)/Ti-D at 160℃was 18.3 times that of untreated Pt_(SA)/Ti-D.Comprehensive characterization results indicated that the N_(2)treatment of the Pt single-atom defect catalyst facilitated the reconfiguration and evolution of the defect structure,leading to the aggregation of Pt single atoms into fully exposed Pt clusters.Notably,these fully exposed Pt clusters exhibited a reduced coordination of Pt–O in the first coordination shell compared to single atoms,which resulted in the formation of Pt–Pt metal coordination.This unique coordination structure enhanced the adsorption and activation of CO and O_(2)on the catalyst,thereby resulting in exceptionally low-temperature CO oxidation activity.This work demonstrates a promising strategy for the design,synthesis,and industrial application of efficient low-platinum load catalysts.
基金National Natural Science Foundation of Joint Fund in China (U22A20376)。
文摘Objective To investigate the therapeutic efficacy and potential mechanisms of fecal microbiota transplantation(FMT)in patients with type 2 diabetes mellitus(T2DM),and to preliminarily identify the traditional Chinese medicine(TCM)syndrome element characteristics of FMT in the treatment of T2DM.Methods Between March 25,2023 and September 30,2024,T2DM patients who met the inclusion and exclusion criteria were enrolled at the Department of Rheumatology and Endocrinology of the Second Affiliated Hospital of Fujian University of Traditional Chinese Medicine.Participants received oral microbiota capsules as an adjunct to metformin therapy.Information obtained by four diagnostic methods of TCM,along with clinical and laboratory parameters,was collected before and after the intervention.Metagenomic sequencing was employed to analyze the gut microbiota,and Spearman correlation analysis was used to explore the relationship between laboratory indicators and differential bacterial genera.According to the post-treatment reduction in glycosylated hemoglobin(HbA1c),patients were categorized into a response(R)group and a non-response(NR)group.Treatment outcomes,safety indicators,gut microbiota changes,and TCM syndrome element features were compared between the two groups.Results A total of 53 T2DM patients were included in the final analysis,and 30 patients were assigned to R group and 23 to NR group.After treatment,the R group exhibited significant reductions in HbA1c,fasting plasma glucose(FPG),and 2-hour postprandial glucose(2hPG)(P<0.05 or P<0.01).The NR group also showed significant decreases in HbA1c and FPG levels P<0.01 or P<0.05.Compared with the NR group,after treatment,FPG level in the R group demonstrated significant reductions(P<0.01).As compared with before treatment,pancreatic islet function demonstrated enhancement in the R group,a significant increase in the 2-hour pastprandial C-peptide(2hC-P)levels in R group(P<0.05),whereas no marked change was observed in the NR group.Regarding body composition indicators,the R group showed significantly lower waist-hip ratio(WHR),visceral fat(VF),and subcutaneous fat(SF)levels compared with the NR group(P<0.01).After treatment,the NR group exhibited a significant elevation in aspartate aminotransferase(AST)levels(P<0.05).Other safety-related indicators fluctuated within normal reference ranges,and no other adverse events,such as diarrhea,fever,or nausea,were reported.Metagenomic sequencing showed that FMT improved the diversity and richness of the gut microbiota,remodeling its overall structure.At the phylum level,the abundance of p_Firmicutes decreased significantly(P<0.01),while the abundances of p_Bacteroidota and p_Proteobacteria increased significantly(P<0.01).At the family level,among the 125 identified taxa,the abundances of f_Bacteroidaceae,f_Lactobacillaceae,and f_Sutterellaceae were significantly elevated,whereas six families,including f_Lachnospiraceae,f_Ruminococcaceae,and f_Coriobacteriaceae,were significantly decreased(all P<0.05).Among the 367 taxa at the genus level,the top 10 differential genera showed significantly increased abundances of g_Bacteroides and g_Sutterella,and significantly decreased abundances in eight genera,including g_Faecalibacterium,g_Ruminococcus,g_Blautia,and g_Collinsella(all P<0.05).Correlation analysis suggested that the phylum p_Bacillota was positively correlated with improvements in T2DM laboratory parameters,g_norank_f_Prevotellaceae was significantly positively correlated with fasting C-peptide(FC-P)and 2hC-P(P<0.05).HbA1c demonstrated a significantly positive correlation with g_Blautia and g_Gemmiger(P<0.05)and a significantly negative correlation with g_Bacteroides and g_Collinsella(P>0.05).Analysis of syndrome element characteristics revealed that the R group was primarily characterized by pathological patterns of dampness,phlegm,and Yang deficiency.Before treatment,statistically significant reductions in syndrome element scores were observed for dampness,Yang deficiency,spleen,phlegm,Qi deficiency,Qi stagnation,and Yin deficiency(P<0.01),as well as for heat and liver(P<0.05).The NR group was mainly featured with Qi deficiency and Yin deficiency.Statistically significant changes in their syndrome element scores after treatment were noted for Qi deficiency(P<0.01),and for spleen,Qi stagnation,liver,and blood deficiency(P<0.05).In this group,the score changes for Yang deficiency,Yin deficiency,heat,and dampness were not statistically significant(P>0.05).Conclusion The principles of syndrome element differentiation can be effectively applied to predict treatment efficacy and facilitate patient selection for FMT in the treatment of T2DM.Patients with T2DM presented with specific TCM syndrome element characteristics,notably dampness,phlegm,and Yang deficiency,represent a highly responsive population to FMT therapy.
基金support by the National Key R&D Program of China(No.2022YFB3402200)the Program of Shanghai Academic Research Leader(No.22XD1421600).
文摘Diffusion-bonded Ti_(2)AlNb-based alloys commonly present a low strength compared with the deformed or aged ones. In this study, the post heat treatment including solution and aging treatments is proposed to optimize the microstructure, contributing to strength improvement and appropriate ductility sacrifice. An available method by the introduction of fine size (both 20-100 nm) and a high fraction (59.7% and 13.7%) of O and α_(2) phases using both solution at 1000℃ for 1 h and aging at 750℃ for 5 h can result in excellent tensile strength (992 MPa and 858 MPa) at room temperature and 650℃, respectively, which increases 5.3% and 44.5% than that of as-received sample. The aging treatment can contribute to lamellar O and α2 grains precipitated from the B_(2) parent, which results in limited dislocation slip systems and slip spaces to resist plastic deformation. Moreover, the crack propagation and fracture surfaces are also comparatively analyzed to reveal the fracture behaviors in the samples with high and low strength. This study can provide a new method for the mechanical property optimization of the welded Ti_(2)AlNb alloys.
基金supported by the Sanming University(No.23YG05)the Science Foundation of Fujian Province(No.2023J011027).
文摘Formaldehyde(HCHO)is a significant indoor pollutant found in various sources and poses potential health risks to humans.Noble metal catalysts show efficient and stable catalytic activity for ambient-temperature HCHO oxidation,yet suffer from low metal utilization.Efforts focus on designing catalysts with enhanced intrinsic activity and reduced noble metal loading.In this study,we developed a simple pretreatment method using ammonia solution on SiO_(2)carrier to enhance the activity of the Pd/SiO_(2)catalyst for HCHO oxidation.After the carrier was pretreated with an ammonia solution,a significant promoting effect was observed on the Pd/SiO_(2)(NH_(3)·H_(2)O)-R catalyst.It achieved almost complete oxidation of 150 ppmV of HCHO at 25℃,much better than the Pd/SiO_(2)-R(5%HCHO conversion rate).Multiple characterization results indicated that the ammonia solution pretreatment of the SiO_(2)carrier increased the surface defects,facilitating the anchoring of Pd nanoparticles and increasing their dispersion.The increase dispersion of Pd resulted in the generation of additional oxygen vacancies on the catalyst surfaces.The increased in oxygen vacancies on the catalyst was beneficial for enhancing the catalyst's ability to activate H_(2)O to form surface hydroxyl groups,thereby accelerating the catalytic oxidation process of HCHO.The reaction mechanism of HCHO on the Pd/SiO_(2)(NH_(3)·H_(2)O)-R catalyst mainly follows an efficient pathway:firstly,the HCHO being oxidized by surface active hydroxyl groups to formate;subsequently,the formate being oxidized by hydroxyl groups to H_(2)O and CO_(2).This study provides a promising strategy for designing high-performance noble metal catalysts for HCHO catalytic oxidation.
基金This study was approved by the ethics committee of the First People’s Hospital of Fuzhou City(No.FZ202103).
文摘BACKGROUND Gastric cancer is one of the most common malignant tumors worldwide,with its incidence and mortality rates ranking among the highest in gastrointestinal cancers.The overexpression or gene amplification of human epidermal growth factor receptor 2(HER-2)occurs in approximately 15%-20%of gastric cancers and serves as a critical molecular target influencing prognosis and treatment out-comes.For patients with HER-2-positive gastric cancer,trastuzumab combined with platinum-based chemotherapy has been established as the standard first-line treatment.However,despite the demonstrated clinical benefits in prolonging survival,the overall efficacy remains limited.In recent years,with the successful application of immune checkpoint inhibitors(ICIs)in various malignant tumors,combining ICIs with existing standard treatment regimens has emerged as a promising approach to enhance the therapeutic efficacy of HER-2-positive gastric cancer.Nevertheless,the efficacy and prognostic factors of ICIs combined with trastuzumab and chemotherapy in HER-2-positive gastric cancer remain unclear.AIM To analyze the efficacy of ICIs combined with standard treatment regimens and the prognostic factors in patients with advanced HER-2-positive gastric cancer.METHODS Clinical data from 104 patients with advanced HER-2-positive gastric cancer who were treated at our hospital between March 2021 and May 2023 were retrospectively analyzed.Patients were divided into a control group(n=54,treated with trastuzumab combined with platinum-based chemotherapy as the standard regimen)and an observation group(n=50,treated with ICIs in addition to the standard regimen).The therapeutic efficacy,survival outcomes,and adverse reactions were compared between the two groups.Univariate and Cox multivariate analyses were performed to identify factors influencing patient prognosis.RESULTS With a median follow-up time of 14.6 months,there were no significant differences between the two groups in terms of objective response rate or disease control rate(P>0.05).The median progression-free survival(mPFS)and mPFS for patients with immunohistochemistry 3+in the observation group were significantly higher than those in the control group(P<0.05).Among patients in the observation group,those with positive programmed death-ligand 1(PD-L1)expression had a significantly higher mPFS than those with negative PD-L1 expression(P<0.05).Regarding adverse events,significant differences were observed between the two groups in hypothyroidism and neutropenia(P<0.05).Cox multivariate analysis showed that Eastern Cooperative Oncology Group(ECOG)performance status,peritoneal metastasis,positive programmed death-1 expression,and treatment regimen were independent factors influencing PFS(hazard ratio>1,P<0.05).CONCLUSION ICIs combined with standard treatment regimens for patients with advanced HER-2-positive gastric cancer demonstrate favorable clinical efficacy,significantly prolonging PFS with manageable safety.ECOG performance status,peritoneal metastasis,positive PD-L1 expression,and treatment regimen are independent factors influ-encing PFS,warranting increased clinical attention to patients exhibiting these factors.
基金supported by the National Key R&D Program of China(No.2019YFA0706802)the National Natural Science Foundation of China(Nos.52273085 and 52303113)Key Scientific Research Projects of Colleges and Universities in Henan Province,China(No.24A430045).
文摘The pressing demand for ultrathin and flexible shields to counter electromagnetic interference(EMI)has sparked interest in Ti_(3)C_(2)T_(x)MXene materials due to their exceptional electrical conductivity,tunable surface chemistry,and layered structure.However,pure Ti_(3)C_(2)T_(x)MXene films often lack the mechanical properties required for practical engineering applications,and traditional reinforcement methods tend to reduce electrical conductivity.This work demonstrates an effective strategy to enhance the alignment and densely packed layered structure of Ti_(3)C_(2)T_(x)MXene films by regulating the acidity and alkalinity of Ti_(3)C_(2)T_(x)MXene aqueous solutions.This approach simultaneously improves mechanical strength and electromagnetic interference shielding effectiveness(EMI SE).Compared with original Ti_(3)C_(2)T_(x)MXene films,MXene films modified with ammonia solution(NH_(3)·H_(2)O)via OH-show a significant improvement in tensile strength(27.7±1.9 MPa).Meanwhile,MXene films treated with hydrochloric acid(HCl)via H^(+)reach an even higher tensile strength of 39±1.5 MPa.Moreover,the EMI SE values of the treated MXene films increase significantly,each reaching 66.2 and 58.4 dB.The maximum improvements in EMI SE values for the acid-and alkali-treated samples are 17.9%and 4%,respectively.In conclusion,the simultaneous enhancement of mechanical strength and EMI shielding efficacy highlights the potential of acid-and alkali-treated Ti_(3)C_(2)T_(x)MXene films for applications in ultrathin and flexible EMI shielding materials.
基金supported by the National Key Basic Research Program of China (2022YFA1402904)Basic Research Project of Shanghai Science and Technology Innovation Action (grant number 24CL2900900)the National Natural Science Foundation of China (grant number 61904034)
文摘Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices.During bipolar high electric-field cycling in numbers close to dielectric breakdown,the dielectric permittivity suddenly increases by 30 times after oxygen-vacancy ordering and ferroelectric-to-nonferroelectric phase transition of near-edge plasma-treated Hf_(0.5)Zr_(0.5)O_(2) thin-film capacitors.Here we report a much higher dielectric permittivity of 1466 during downscaling of the capacitor into the diameter of 3.85μm when the ferroelectricity suddenly disappears without high-field cycling.The stored charge density is as high as 183μC cm^(−2) at an operating voltage/time of 1.2 V/50 ns at cycle numbers of more than 10^(12) without inducing dielectric breakdown.The study of synchrotron X-ray micro-diffraction patterns show missing of a mixed tetragonal phase.The image of electron energy loss spectroscopy shows the preferred oxygen-vacancy accumulation at the regions near top/bottom electrodes as well as grain boundaries.The ultrahigh dielectric-permittivity material enables high-density integration of extremely scaled logic and memory devices in the future.
文摘2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al） matrix of 2A97 alloy processed by the heat treatment with no pre-stretch deformation. When the pre-stretch deformation is 3% and 6%, respectively, amounts of tiny T1 and a few of S＇ precipitates precipitates are observed in the microstructures of 2A97 alloy. The tensile test results show that the tensile properties of 2A97 alloys are improved via thermo-mechanical treatment. When the pre-stretch deformation is from 0, 3% to 6%, the ultimate tensile strength values of the 2A97 alloys increase gradually from 447.7, 516.5 to 534.3 MPa, and the elongations decrease from 17.6%, 12.8% to 10.2%, respectively. Moreover, with increasing pre-stretch deformation amount from 0 to 6%, the in-plane anisotropy value of 2A97 alloys becomes more obvious.
基金Project(0502)supported by the Aerospace Science and Technology Innovation Fund of China Aerospace Science and Technology CorporationProject(2007CB613701)supported by the National Basic Research Program of ChinaProject(2009AA033501)supported by the National High-tech Research and Development Program of China
文摘Influence of heat treatment on the microstructures and mechanical properties of sand-cast Mg-4Y-2Nd-1Gd-0.4Zr magnesium alloy was investigated,and the tensile fracture mechanisms of the studied alloys under different conditions were also discussed.The results show that the optimum T4 and T6 heat treatment conditions for the as-cast Mg-4Y-2Nd-1Gd-0.4Zr alloy are 525°C,8 h and（525°C,8 h）＋（225°C,16 h）,respectively,with regard to the microstructure observation,DSC heating curve and mechanical properties.The hardness,yield strength,ultimate tensile strength and elongation of the Mg-4Y-2Nd-1Gd-0.4Zr alloy treated by optimum T6 heat treatment are HV91,180 MPa,297 MPa and 7.4%,respectively.Moreover,the Mg-4Y-2Nd-1Gd-0.4Zr alloys under different heat treatment conditions exhibit different tensile fracture modes.
基金Project (BG2007030) supported by High-tech Research Program of Jiangsu Province, ChinaProject (07KJA43008) supported by the Natural Science Foundation of Jiangsu Province, ChinaProject (20070299004) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The influence of solution treatment on the microstructure and properties of Mg2Si/AZ91D composites fabricated from Mg-SiO2 system via in-situ processing method was investigated.The results show that coarse Chinese script shape Mg2Si phases can be formed by adding SiO2 into AZ91D magnesium alloy with Si content up to 1.5% of the alloy melt.During solution treatment,the morphology and distribution of the coarse Chinese script shape Mg2Si phases are modified.Meanwhile,the β-Mg17Al12 phase is dissolved into the magnesium matrix.With increasing holding time,the coarse Mg2Si phases tend to dissolve,break and spheroidize.After solution treatment at 420 ℃ for 16 h,Mg2Si phases become the finest and relatively well-distributed phase.The tensile strength and elongation are increased by 14.9% and 38.9%,respectively.It is believed that the Mg2Si phases continuously dissolve and break,and finally the spheroidized Mg2Si particles are obtained due to the interface tension of Mg2Si/Mg interface.
基金Project(cstc2015jcyj BX0036)supported by Chongqing Research Program of Basic Research and Frontier Technology,ChinaProject(51571040)supported by the National Natural Science Foundation of ChinaProject supported by the Sharing Fund of Chongqing University’s Large-scale Equipment,China
文摘The effects of the ultrasonic treatment on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy were investigated. The results show that the ultrasonic treatment has significant effect on the microstructure and mechanical properties of Mg-6Zn-0.5Y-2Sn alloy. The phases in Mg-6Zn-0.5Y-2Sn alloy are α-Mg, MgZn2, MgSnY, Mg2Sn, and a small amount of I-phase. With the application of ultrasonic treatment, I-phase nearly disappears, and with increasing the ultrasonic treatment power, the coarse dendrites gradually change into roundish equiaxed grains. The second phases at the α-Mg boundaries transform from coarse, semicontinuous and non-uniform to fine, discontinuous, uniform and dispersive. When the ultrasonic treatment power is 700 W, the best comprehensive mechanical properties of Mg-6Zn-0.5Y-2Sn alloy are obtained. Compared with the untreated alloy, the 0.2%tensile yield strength, ultimate tensile strength and elongation are improved by 28%, 30%and 67%, respectively.
基金Project(2009BAE71B00) supported by the National Key Technology R&D Program during the Eleventh Five-Year Plan Period
文摘The microstructures of as-extruded and stabilizing heat-treated Zn-10Al-2Cu-0.02Ti alloys were observed by scanning electron microscopy,transmission electron microscopy,electron probe microanalysis and X-ray diffraction analysis techniques.The change in structure after heat treatment and its effects on room temperature creep behavior were investigated by creep experiments at constant stress and slow strain rate tensile tests.The results show that after stabilizing heat treatment（（350℃,30 min,water-cooling）＋（100℃,12 h,air-cooling））,the amount of α＋η lamellar structure decreases,while the amount of cellular and granular structure increases.The heat-treated Zn-10Al-2Cu-0.02Ti alloy exhibits better creep resistance than the as-extruded alloy,and the rate of steady state creep decreases by 96.9% after stabilizing heat treatment.
