Ti-6.5 Al-2.5 Sn-9 Zr-0.5 Mo-0.25 Si-1 Nb-1 W-0.1 Er-x B(x=0,0.1,0.2,0.4,0.6 and 0.8 wt%)with different boron contents are fabricated for investigation.Influences of boron element and its amounts on phase constitution...Ti-6.5 Al-2.5 Sn-9 Zr-0.5 Mo-0.25 Si-1 Nb-1 W-0.1 Er-x B(x=0,0.1,0.2,0.4,0.6 and 0.8 wt%)with different boron contents are fabricated for investigation.Influences of boron element and its amounts on phase constitutions,microstructures,textures and compression mechanical properties are carefully studied.With the increasing boron additions,contents of TiB phase increase,and the maximum intensities of textures decrease.Microstructures are significantly and continuously refined after adding boron element and with the increasing boron additions,and turning point of refinement rates for different microstructural parameters is found at 0.2 wt%boron content.Strengths increase monotonously,while elongations increase firstly and decrease afterwards.The maximum value of elongation is acquired at boron content of 0.2 wt%.On the premise of ensuring plasticity,0.2 wt%boron content is the most appropriate amount for microstructural refinement and mechanical properties enhancement for current nearαtitanium alloys.Meanwhile,aspect ratios of TiB whiskers increase with the increasing boron contents.Lots of near equiaxedαgrains orαgrains with irregular morphologies are discovered around TiB phase.Distorted and twistedαgrain boundaries are also obviously detected in boron containing alloys.Moreover,premature fracture of alloys containing TiB whiskers is largely influenced by the fracture of these brittle reinforcements.展开更多
The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity...The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity fading and phase change of MnO_(2)-based materials in aqueous zinc ion batteries(AZIBs).Here,this study doped high valent vanadium ions into MnO_(2)(VMO-x)to inhibit manganese's Jahn-Teller effect.Through a series of characterizations,such as X-ray diffraction(XRD),Raman spectroscopy,and scanning electron microscopy(SEM),it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO_(2),facilitating the transport of ions into the interlayer.Additionally,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)demonstrated vanadium doped could effectively adjust the electronic structure,decreasing the average oxidation state of manganese,thereby inhibiting the Jahn-Teller effect and significantly enhancing the stability of the VMO-x cathode.The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn^(2+),optimized its electron transport capacity,and led to better electrical conductivity and reaction kinetics of the VMO-5.Benefiting from this,the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79%after 2000 cycles,demonstrating excellent electrochemical performance.Furthermore,the mechanism of H^(+)/Zn^(2+)co-intercalation/deintercalation was demonstrated through mechanism analysis.Finally,the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices.This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.展开更多
Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive ...Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.展开更多
Vascular stents play an important role in the minimally invasive treatment of vascular diseases,such as vascular stenosis,vascular aneurysm,vascular dissection and vascular atherosclerotic plaque disease.Bare metal st...Vascular stents play an important role in the minimally invasive treatment of vascular diseases,such as vascular stenosis,vascular aneurysm,vascular dissection and vascular atherosclerotic plaque disease.Bare metal stents were initially fabricated;however,the incidence of complications such as thrombosis,inflammation,restenosis,vascular injury,displacement and endoleakage is still high after implantation.To overcome these complications,several strategies for designing functional vascular stents have been carried out.Drug-eluting stents,biodegradable stents and bionic stents were manufactured and investigated.This review aims to comprehensively analyze the vascular diseases suitable for stent implantation treatment,tissue reactions after implantation,the materials and manufacturing techniques used to fabricate vascular stents,the various application scenarios in which they could be used to treat vascular lesions and the development process of vascular stents.Future development trends of vascular stents are expected to prioritize their performance,biocompatibility,and clinical accessibility.The design of vascular stents may be transformed or improved to better fulfill the rehabilitation requirements of vascular disease patients.Finally,various application scenarios may be used to treat vascular or even nonvascular diseases via endovascular access.展开更多
Grain size is one of the most important factors affecting rice grain quality and yield,and attracts great attention from molecular biologists and breeders.In this study,we engineered a CRISPR/Cas9 system targeting the...Grain size is one of the most important factors affecting rice grain quality and yield,and attracts great attention from molecular biologists and breeders.In this study,we engineered a CRISPR/Cas9 system targeting the miR396 recognition site of the rice GS2 gene,which encodes growth-regulating factor 4(OsGRF4)and regulates multiple agronomic traits including grain size,grain quality,nitrogen use efficiency,abiotic stress response,and seed shattering.In contrast to most previous genome editing efforts in which indel mutations were chosen to obtain null mutants,a mutant named GS2^(E) carrying an in-frame 6-bp deletion and 1-bp substitution within the miR396-targeted sequence was identified.GS2^(E) plants showed increased expression of GS2 in consistent with impaired repression by miR396.As expected,the gain-of-function GS2^(E) mutant exhibited multiple beneficial traits including increased grain size and yield and bigger grain length/width ratio.Thousand grain weight and grain yield per plant of GS2^(E) plants were increased by 23.5%and 10.4%,respectively.These improved traits were passed to hybrids in a semidominant way,suggesting that the new GS2^(E) allele has great potential in rice improvement.Taken together,we report new GS2 germplasm and describe a novel gene-editing strategy that can be widely employed to improve grain size and yield in rice.This trait-improvement strategy could be applied to other genes containing miRNA target sites,in particular the conserved miR396-GRF/GIF module that governs plant growth,development and environmental response.展开更多
As an outstanding representative of layered materials,molybdenum disulfide(MoS_(2))has excellent physical properties,such as high carrier mobility,stability,and abundance on earth.Moreover,its reasonable band gap and ...As an outstanding representative of layered materials,molybdenum disulfide(MoS_(2))has excellent physical properties,such as high carrier mobility,stability,and abundance on earth.Moreover,its reasonable band gap and microelectronic compatible fabrication characteristics makes it the most promising candidate in future advanced integrated circuits such as logical electronics,flexible electronics,and focal-plane photodetector.However,to realize the all-aspects application of MoS_(2),the research on obtaining high-quality and large-area films need to be continuously explored to promote its industrialization.Although the MoS_(2)grain size has already improved from several micrometers to sub-millimeters,the high-quality growth of wafer-scale MoS_(2)is still of great challenge.Herein,this review mainly focuses on the evolution of MoS_(2)by including chemical vapor deposition,metal–organic chemical vapor deposition,physical vapor deposition,and thermal conversion technology methods.The state-of-the-art research on the growth and optimization mechanism,including nucleation,orientation,grain,and defect engineering,is systematically summarized.Then,this review summarizes the wafer-scale application of MoS_(2)in a transistor,inverter,electronics,and photodetectors.Finally,the current challenges and future perspectives are outlined for the wafer-scale growth and application of MoS_(2).展开更多
Tuning the photoresponse of monolayer MoS_(2) could extend its potential application in many fields,however,it is still a challenge.In this study,CsPbBr_(3) nanoparticles were prepared and spin-coated on the surface o...Tuning the photoresponse of monolayer MoS_(2) could extend its potential application in many fields,however,it is still a challenge.In this study,CsPbBr_(3) nanoparticles were prepared and spin-coated on the surface of monolayer MoS_(2) to fabricate hybrid CsPbBr_(3)/MoS_(2) photodetectors.By combing the photoelectrical property of the CsPbBr_(3),the synergistic effect has been systematically studied from its carrier mobility,photoresponse and detectivity.It was found that nanofilm-coating of CsPbBr_(3)would impede the photoelectric performance due to the electron-hole recombination facilitated by the defects at the interface of C PbBr_(3) and MoS_(2) films.While the nanoparticles decorating was observed to significantly improve the conductivity of the monolayer Mo S_(2),which also increased the on/off ratio of the MoS_(2) transistor from 8.2×10~3 to 4.4×10^(4),and enhanced the carrier mobility from 0.090 cm^(2)V^(-1)s^(-1)to 0.202 cm^(2)V^(-1)s^(-1),ascribing to a mixed electron recombination-injection process.Furthermore,the CsPbBr_(3) nanofilm would decrease the responsivity to 136 and 178 A/W under the light wavelength of 400 and 500 nm,respectively,while decorating CsPbBr_(3) nanoparticles improve the photoresponse to 948 and 883 A/W with the detectivity at the level of 10^(11)Jones.This work may provide an easy and cost-efficient way to tune the photoresponse of MoS_(2) photodetectors.展开更多
Vegetation in wetlands is a large-scale nature-based resource that can provide multiple benefits to human beings and the environment,such as wave attenuation in coastal zones.Traditionally,there are two main calibrati...Vegetation in wetlands is a large-scale nature-based resource that can provide multiple benefits to human beings and the environment,such as wave attenuation in coastal zones.Traditionally,there are two main calibration approaches to calculate the attenuation of wave driven by vegetation.The first method is a straightforward one based on the exponential attenuation of wave height in the direction of wave transmission,which,however,overlooks the crucial drag coefficient(CD).The other method is in accordance with more complicate equations for predicting the damping factor,which is regarded as a function of CD.In this study,a new relation,combining these above two conventional approaches,is proposed to predict the CD in an operative approach.Results show that values yielded by the new assessment method perform a strong linear relationship with a collection of historical observations,with a promising R2 value of 0.90.Besides,the linear regression derives a new predictive equation for the bulk drag coefficient.Additionally,a calibrated value of 4 for the empirical plant drag coefficient(CP)is revealed.Overall,this new equation,with the superiority of the convenient exponential regression,is expected to be a rapid assessment method for calculating wave attenuation by vegetation and predicting the drag coefficient.展开更多
The potential association between medical resources and the proportion of oldest-old(90 years of age and above)in the Chinese population was examined,and we found that the higher proportion of oldest-old was associate...The potential association between medical resources and the proportion of oldest-old(90 years of age and above)in the Chinese population was examined,and we found that the higher proportion of oldest-old was associated with the higher number of beds in hospitals and health centers.展开更多
Fruit ripening is influenced by multiple plant hormones and the regulation of genes.However,studies on posttranscriptional regulators(e.g.,miRNAs)of fruit growth and ripening are limited.We used miRNA sequencing and d...Fruit ripening is influenced by multiple plant hormones and the regulation of genes.However,studies on posttranscriptional regulators(e.g.,miRNAs)of fruit growth and ripening are limited.We used miRNA sequencing and degradome methods to identify miRNAs and their target genes in melon(Cucumis melo cv.Hetao melon).A total of 61 conserved miRNAs and 36 novel miRNAs were identified from fruit growth,ripening,climacteric,and postclimacteric developmental stage samples,of which 32 conserved miRNAs were differentially expressed between developmental stage samples.Sixty-two target genes of 43 conserved miRNAs and 1 novel miRNA were identified from degradome sequencing.To further investigate miRNA influencing fruit ripening,transgenic melon plants overexpressing pre-cmemiR393(cme-miR393-OE)were generated and characterized.The results showed that fruit ripening was delayed in cme-miR393-OE transgenic lines compared to nontransgenic fruits.The target of cme-miR393 was also identified,and the expression of CmAFB2 was repressed in transgenic plants.These results provide evidence that miRNA regulates melon fruit ripening and provide potential targets to improve the horticultural traits of melon fruit.展开更多
Background:When lowlanders rapidly ascend to altitudes>2500 m,they may develop acute mountain sickness(AMS).The individual susceptibility,ascending velocity,time spent at altitude,activity levels and altitude reach...Background:When lowlanders rapidly ascend to altitudes>2500 m,they may develop acute mountain sickness(AMS).The individual susceptibility,ascending velocity,time spent at altitude,activity levels and altitude reached are considered risk factors for AMS.However,it is not clear whether sex is a risk factor.The results have been inconclusive.We conducted a meta-analysis to test whether there were sex-based differences in the prevalence of AMS using Lake Louise Scoring System.Methods:Systematic searches were performed in August 2019 in EMBASE,PubMed,and Web of Science for prospective studies with AMS data for men and women.The titles and abstracts were independently checked in the primary screening step,and the selected full-text articles were independently assessed in the secondary screening step by the two authors(YPH and JLW)based on pre-defined inclusion criteria.The meta-analysis was performed using by the STATA 14.1 software program.A random-effects model was employed.Results:Eighteen eligible prospective studies were included.A total of 7669 participants(2639[34.4%]women)were tested.The results showed that there was a statistically significant higher prevalence rate of AMS in women than in men(RR=1.24,95%CI 1.09–1.41),regardless of age or race.However,the heterogeneity was significant in the analysis(Tau2=0.0403,Chi2=50.15,df=17;I2=66.1%,P=0.000),it was main caused by different numbers of subjects among the studies(coefficient=–2.17,P=0.049).Besides,the results showed that there was no evidence of significant publication bias in the combined studies on the basis of Egger’s test(bias coefficient=1.48,P=0.052)and Begg’s test(P=0.130).Conclusions:According to this study,the statistically significant finding emerging from this study was that women have a higher prevalence of AMS.However,the authors could not exclude studies where patients were on acetazolamide.Our analysis provided a direction for future studies of the relationship of sex and the risk of AMS,such as the pathological mechanism and prevention research.展开更多
OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activit...OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/ kg) twice daily for 3 days. RESULTS: IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100or 200 mg/kg) had no significant effect on APTT and PT, but did lengthenTT at a higher dose. CONCLUSION: These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.展开更多
CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated repairing.In order to study the...CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated repairing.In order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics,an finite element method(FEM)mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations,to explore the 3D near-field light intensity distribution inside optics with repaired site on its surface.The influences of the cone angle and the size of the repaired site on incident laser modulation are studied as well.The results have shown that for the repaired site with a cone angle of 73.3°,the light intensity distribution has obvious three-dimensional characteristics.The relative light intensity on z-section has a circularly distribution,and the radius of the annular intensification zone increases with the decrease of z.While the distribution of maximum relative light intensity on y-section is parabolical with the increase of y.As the cone angle of the repaired site decreases,the effect of the repaired surface on light modulation becomes stronger,leading to a weak resistance to laser damage.Moreover,the large size repaired site would also reduce the laser damage threshold.Therefore,a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface damage.This work will provide theoretical guidance for the design of repaired surface topography,as well as the improvement of RAM process.展开更多
With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impre...With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impregnation method.By using X-ray diffraction and X-ray photoelectron spectroscopy extrapolation methods,it is disclosed that CuO disperses finely on the SnO2 support to form a monolayer with a capacity of 2.09 mmol 100 m^-2,which equals 4.8 wt%CuO loading.When the CuO loading is below the capacity,it is in a sub-monolayer state.However,when the loading is above the capacity,CuO micro-crystallites will be formed that coexist with the CuO monolayer.The soot combustion activity of the catalyst increases with the CuO loading until it reaches the monolayer dispersion capacity.A further increase in the CuO loading has no evident influence on the activity.Raman results have testified that with the addition of CuO onto the SnO2 support,a surface-active oxygen species can be formed,the amount of which also increases significantly with the increase in the CuO loading until it reaches the monolayer dispersion capacity.Increasing the CuO loading further has no evident impact on the amount of surface oxygen.Therefore,an apparent monolayer dispersion threshold effect is observed for soot combustion over CuO/SnO2 catalysts.It is concluded that the amount of surface-active oxygen sites is the major factor determining the activity of the catalyst.展开更多
Magnetism in two-dimensional(2D)materials has attracted much attention recently.However,intrinsic magnetic 2D materials are rare and mostly unstable in ambient.Although heteroatom doping can introduce magnetism,the ba...Magnetism in two-dimensional(2D)materials has attracted much attention recently.However,intrinsic magnetic 2D materials are rare and mostly unstable in ambient.Although heteroatom doping can introduce magnetism,the basic property especially the electrical-magnetic coupling property has been rarely revealed.Herein,both iron(Fe)-doped and vanadium(V)-doped MoSfilms were grown by chemical vapor deposition.Through studying the structure and electrical property of Fe-doped and V-doped MoS,it was found that both Fe and V doping would decrease the electron concentration,exhibiting a p-type doping effect.Significantly,V-doped MoSdisplays a p-type conduction behavior.Although the carrier mobility decreases after heteroatom doping,both Fe and V doping could endow MoSwith magnetism,in which the transfer curves of both MoStransistors exhibit a strong magneticdependent behavior.It is found that the magnetic response of Fe-doped MoScan be tuned from~0.2 nA/T to~1.3 nA/T,with the tunability much larger than that of V-doped MoS.At last,the magnetic mechanism is discussed with the local magnetic property performed by magnetic force microscopy.The typical morphology-independent magnetic signal demonstrates the formed magnetic domain structure in Fe-doped MoS.This study opens new potential to design novel magnetic-electrical devices.展开更多
In the last few years,smartphone usage and driver sleepiness have been unanimously considered to lead to numerous road accidents,which causes many scholars to pay attention to autonomous driving.For this complexity sc...In the last few years,smartphone usage and driver sleepiness have been unanimously considered to lead to numerous road accidents,which causes many scholars to pay attention to autonomous driving.For this complexity scene,one of the major challenges is mining information comprehensively from massive features in vehicle video.This paper proposes a multi-label classification method MCM-VV(Multi-label Classification Method for Vehicle Video)for vehicle video to judge the label of road condition for unmanned system.Method MCM-VV includes a process of feature extraction and a process of multi-label classification.During feature extraction,grayscale,lane line and the edge of main object are extracted after video preprocessing.During the multi-label classification,the algorithm DR-ML-KNN(Multi-label K-nearest Neighbor Classification Algorithm based on Dimensionality Reduction)learns the training set to obtain multi-label classifier,then predicts the label of road condition according to maximum a posteriori principle,finally outputs labels and adds the new instance to training set for the optimization of classifier.Experimental results on five vehicle video datasets show that the method MCM-VV is effective and efficient.The DR-ML-KNN algorithm reduces the runtime by 50%.It also reduces the time complexity and improves the accuracy.展开更多
Currently, phosphate based glasses have been potential future biomaterial for medical application due to excellent cytocompatibility and fully bioresorbability. In this study, phosphate based glass system with composi...Currently, phosphate based glasses have been potential future biomaterial for medical application due to excellent cytocompatibility and fully bioresorbability. In this study, phosphate based glass system with composition of 48P2O5-12B2O3-(25-X)MgO-14CaO-1Na2O-(X)Fe2O3 (X = 6, 8, 10) and 45P2O5-(Y)B2O3-(32-Y)MgO-14CaO-1Na2O-8Fe2O3 (Y = 12, 15, 20), was prepared via a melting quenching process. The effect of replacing MgO with Fe2O3 and B2O3 on the structural, thermal, degradation properties of phosphate based glass was investigated. Fourier Transform Infrared (FTIR) spectroscopy and Raman spectroscopy analysis confirmed the polymerisation of phosphate based glass network with addition of Fe2O3, thus the processing window was observed to increase whilst the dissolution rate was reduced, attributed to the formation of Fe-O-P cross-link. As the effect on the glass structure stability was demonstrated by both B2O3 and MgO, the nonlinear variation of thermal stability and degradation behaviour was observed for glass system with substitution of MgO by B2O3. However, due to the lower dissolution rate of glass system when compared to the biocompatible phosphate based glass in preliminary study, the expected cytocompatibility could be confirmed in the downstream activities.展开更多
According to smoothness assumption,local topological structure can be shared between feature and label manifolds.This study proposes a new algorithm based on Local Tangent Space Alignment(LTSA)to implement the label e...According to smoothness assumption,local topological structure can be shared between feature and label manifolds.This study proposes a new algorithm based on Local Tangent Space Alignment(LTSA)to implement the label enhancement process.In general,we first establish a learning model for feature extraction in label space and use a feature extraction method of LTSA to guide the reconstruction of label manifolds.Then,we establish an unconstrained optimization model based on the optimal theory presented in this paper.The model is suitable for solving problems with a large number of sample points.Finally,the experiment results show that the algorithm can effectively improve the training speed and multilabel dataset prediction accuracy.展开更多
基金the Industrial Strengthen Foundation Project of Ministry of Industry and Information Technology,PRC(No.TC150B5C0-02)。
文摘Ti-6.5 Al-2.5 Sn-9 Zr-0.5 Mo-0.25 Si-1 Nb-1 W-0.1 Er-x B(x=0,0.1,0.2,0.4,0.6 and 0.8 wt%)with different boron contents are fabricated for investigation.Influences of boron element and its amounts on phase constitutions,microstructures,textures and compression mechanical properties are carefully studied.With the increasing boron additions,contents of TiB phase increase,and the maximum intensities of textures decrease.Microstructures are significantly and continuously refined after adding boron element and with the increasing boron additions,and turning point of refinement rates for different microstructural parameters is found at 0.2 wt%boron content.Strengths increase monotonously,while elongations increase firstly and decrease afterwards.The maximum value of elongation is acquired at boron content of 0.2 wt%.On the premise of ensuring plasticity,0.2 wt%boron content is the most appropriate amount for microstructural refinement and mechanical properties enhancement for current nearαtitanium alloys.Meanwhile,aspect ratios of TiB whiskers increase with the increasing boron contents.Lots of near equiaxedαgrains orαgrains with irregular morphologies are discovered around TiB phase.Distorted and twistedαgrain boundaries are also obviously detected in boron containing alloys.Moreover,premature fracture of alloys containing TiB whiskers is largely influenced by the fracture of these brittle reinforcements.
基金supported the National Key Research and Development Program of China(No.2024YFA1409900)the National Natural Science Foundation of China(Nos.62101296 and 52303335)+2 种基金the China Postdoctoral Science Foundation(Nos.2021M702656 and 2023M730099)the Natural Science Foundation of Shaanxi Province(Nos.2021JQ-756 and 2021M702656)the Graduate Innovation Fund of the School of Mechanical Engineering,Shaanxi University of Technology(No.SLGJX202404)。
文摘The Jahn-Teller effect of Mn^(3+)brings drastic structural changes to MnO_(2)-based materials and accelerates the destruction and deactivation of the internal structure of the materials,thus leading to severe capacity fading and phase change of MnO_(2)-based materials in aqueous zinc ion batteries(AZIBs).Here,this study doped high valent vanadium ions into MnO_(2)(VMO-x)to inhibit manganese's Jahn-Teller effect.Through a series of characterizations,such as X-ray diffraction(XRD),Raman spectroscopy,and scanning electron microscopy(SEM),it was discovered that the introduction of vanadium ions effectively increased the interlayer spacing of MnO_(2),facilitating the transport of ions into the interlayer.Additionally,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)demonstrated vanadium doped could effectively adjust the electronic structure,decreasing the average oxidation state of manganese,thereby inhibiting the Jahn-Teller effect and significantly enhancing the stability of the VMO-x cathode.The theoretical calculation showed that introducing vanadium ions enhanced the interaction between the main material and Zn^(2+),optimized its electron transport capacity,and led to better electrical conductivity and reaction kinetics of the VMO-5.Benefiting from this,the VMO-5 cathode exhibited an outstanding capacity of 283 mAh/g and maintained a capacity retention rate of 79%after 2000 cycles,demonstrating excellent electrochemical performance.Furthermore,the mechanism of H^(+)/Zn^(2+)co-intercalation/deintercalation was demonstrated through mechanism analysis.Finally,the test results of the pouch cell demonstrated the excellent flexibility and safety exhibited by the VMO-5 make it have great potential in flexible devices.This work presented a novel approach to doping high valence metal ions into manganese-based electrodes for AZIBs.
基金financially supported by the National Natural Science Foundation of China(Nos.52272160,U2330112,and 52002254)Sichuan Science and Technology Foundation(Nos.2020YJ0262,2021YFH0127,2022YFH0083,2022YFSY0045,and 2023YFSY0002)+1 种基金the Chunhui Plan of Ministry of Education,Fundamental Research Funds for the Central Universities,China(No.YJ201893)the Foundation of Key Laboratory of Lidar and Device,Sichuan Province,China(No.LLD2023-006)。
文摘Nowadays,force sensors play an important role in industrial production,electronic information,medical health,and many other fields.Two-dimensional material-based filed effect transistor(2D-FET)sensors are competitive with nano-level size,lower power consumption,and accurate response.However,few of them has the capability of impulse detection which is a path function,expressing the cumulative effect of the force on the particle over a period of time.Herein we fabricated the flexible polymethyl methacrylate(PMMA)gate dielectric MoS_(2)-FET for force and impulse sensor application.We systematically investigated the responses of the sensor to constant force and varying forces,and achieved the conversion factors of the drain current signals(I_(ds))to the detected impulse(I).The applied force was detected and recorded by I_(ds)with a low power consumption of~30 nW.The sensitivity of the device can reach~8000%and the 4×1 sensor array is able to detect and locate the normal force applied on it.Moreover,there was almost no performance loss for the device as left in the air for two months.
基金supported by Natural Science Foundation of China(No.31930067)Natural Science Foundation of Sichuan Province(No.23NSFSC5880)+2 种基金Chengdu Medical Research Project(No.2022004)Natural Science Foundation of Clinical Medical College and Affiliated Hospital of Chengdu University(No.Y202206)Postdoctoral Research and Development Fund of West China Hospital,Sichuan University(No.2023HXBH052).
文摘Vascular stents play an important role in the minimally invasive treatment of vascular diseases,such as vascular stenosis,vascular aneurysm,vascular dissection and vascular atherosclerotic plaque disease.Bare metal stents were initially fabricated;however,the incidence of complications such as thrombosis,inflammation,restenosis,vascular injury,displacement and endoleakage is still high after implantation.To overcome these complications,several strategies for designing functional vascular stents have been carried out.Drug-eluting stents,biodegradable stents and bionic stents were manufactured and investigated.This review aims to comprehensively analyze the vascular diseases suitable for stent implantation treatment,tissue reactions after implantation,the materials and manufacturing techniques used to fabricate vascular stents,the various application scenarios in which they could be used to treat vascular lesions and the development process of vascular stents.Future development trends of vascular stents are expected to prioritize their performance,biocompatibility,and clinical accessibility.The design of vascular stents may be transformed or improved to better fulfill the rehabilitation requirements of vascular disease patients.Finally,various application scenarios may be used to treat vascular or even nonvascular diseases via endovascular access.
基金supported by the National Key Research and Development Program of China(2016YFD0102000)“Breeding of Major New Varieties of Main Grain Crops”Program(2020ABA016)from Department of Science and Technology of Hubei Province.
文摘Grain size is one of the most important factors affecting rice grain quality and yield,and attracts great attention from molecular biologists and breeders.In this study,we engineered a CRISPR/Cas9 system targeting the miR396 recognition site of the rice GS2 gene,which encodes growth-regulating factor 4(OsGRF4)and regulates multiple agronomic traits including grain size,grain quality,nitrogen use efficiency,abiotic stress response,and seed shattering.In contrast to most previous genome editing efforts in which indel mutations were chosen to obtain null mutants,a mutant named GS2^(E) carrying an in-frame 6-bp deletion and 1-bp substitution within the miR396-targeted sequence was identified.GS2^(E) plants showed increased expression of GS2 in consistent with impaired repression by miR396.As expected,the gain-of-function GS2^(E) mutant exhibited multiple beneficial traits including increased grain size and yield and bigger grain length/width ratio.Thousand grain weight and grain yield per plant of GS2^(E) plants were increased by 23.5%and 10.4%,respectively.These improved traits were passed to hybrids in a semidominant way,suggesting that the new GS2^(E) allele has great potential in rice improvement.Taken together,we report new GS2 germplasm and describe a novel gene-editing strategy that can be widely employed to improve grain size and yield in rice.This trait-improvement strategy could be applied to other genes containing miRNA target sites,in particular the conserved miR396-GRF/GIF module that governs plant growth,development and environmental response.
基金financially the National Natural Science Foundation of China(52002254,52272160)Sichuan Science and Technology Foundation(2020YJ0262,2021YFH0127,2022YFSY0045,2022YFH0083 and 23SYSX0060)+3 种基金the Chunhui plan of Ministry of Education,Fundamental Research Funds for the Central Universities,China(YJ201893)the Open-Foundation of Key Laboratory of Laser Device Technology,China North Industries Group Corporation Limited(Grant No.KLLDT202104)the foundation of the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP202210)the 2035-Plan of Sichuan University。
文摘As an outstanding representative of layered materials,molybdenum disulfide(MoS_(2))has excellent physical properties,such as high carrier mobility,stability,and abundance on earth.Moreover,its reasonable band gap and microelectronic compatible fabrication characteristics makes it the most promising candidate in future advanced integrated circuits such as logical electronics,flexible electronics,and focal-plane photodetector.However,to realize the all-aspects application of MoS_(2),the research on obtaining high-quality and large-area films need to be continuously explored to promote its industrialization.Although the MoS_(2)grain size has already improved from several micrometers to sub-millimeters,the high-quality growth of wafer-scale MoS_(2)is still of great challenge.Herein,this review mainly focuses on the evolution of MoS_(2)by including chemical vapor deposition,metal–organic chemical vapor deposition,physical vapor deposition,and thermal conversion technology methods.The state-of-the-art research on the growth and optimization mechanism,including nucleation,orientation,grain,and defect engineering,is systematically summarized.Then,this review summarizes the wafer-scale application of MoS_(2)in a transistor,inverter,electronics,and photodetectors.Finally,the current challenges and future perspectives are outlined for the wafer-scale growth and application of MoS_(2).
基金financially supported by the National Natural Science Foundation of China (Nos. 52002254, 52272160)Sichuan Science and Technology Foundation (Nos. 2020YJ0262, 2021YFH0127, 2022YFH0083, 2022YFSY0045)+2 种基金the Chunhui plan of Ministry of Education, Fundamental Research Funds for the Central Universities, China (No. YJ201893)the Open-Foundation of Key Laboratory of Laser Device Technology, China North Industries Group Corporation Limited (No. KLLDT202104)Supported by the fund of the State Key Laboratory of Solidification Processing in NWPU (No. SKLSP202210)。
文摘Tuning the photoresponse of monolayer MoS_(2) could extend its potential application in many fields,however,it is still a challenge.In this study,CsPbBr_(3) nanoparticles were prepared and spin-coated on the surface of monolayer MoS_(2) to fabricate hybrid CsPbBr_(3)/MoS_(2) photodetectors.By combing the photoelectrical property of the CsPbBr_(3),the synergistic effect has been systematically studied from its carrier mobility,photoresponse and detectivity.It was found that nanofilm-coating of CsPbBr_(3)would impede the photoelectric performance due to the electron-hole recombination facilitated by the defects at the interface of C PbBr_(3) and MoS_(2) films.While the nanoparticles decorating was observed to significantly improve the conductivity of the monolayer Mo S_(2),which also increased the on/off ratio of the MoS_(2) transistor from 8.2×10~3 to 4.4×10^(4),and enhanced the carrier mobility from 0.090 cm^(2)V^(-1)s^(-1)to 0.202 cm^(2)V^(-1)s^(-1),ascribing to a mixed electron recombination-injection process.Furthermore,the CsPbBr_(3) nanofilm would decrease the responsivity to 136 and 178 A/W under the light wavelength of 400 and 500 nm,respectively,while decorating CsPbBr_(3) nanoparticles improve the photoresponse to 948 and 883 A/W with the detectivity at the level of 10^(11)Jones.This work may provide an easy and cost-efficient way to tune the photoresponse of MoS_(2) photodetectors.
基金The National Key Research and Development Program of China under contract No.2016YFC0402607the Key Research and Development Projects in Guangdong Province under contract No.2019B111101002+1 种基金the 2018 Guangzhou Science and Technology Project under contract No.201806010143the Water Resource Science and Technology Innovation Program of Guangdong Province under contract No.2017-17。
文摘Vegetation in wetlands is a large-scale nature-based resource that can provide multiple benefits to human beings and the environment,such as wave attenuation in coastal zones.Traditionally,there are two main calibration approaches to calculate the attenuation of wave driven by vegetation.The first method is a straightforward one based on the exponential attenuation of wave height in the direction of wave transmission,which,however,overlooks the crucial drag coefficient(CD).The other method is in accordance with more complicate equations for predicting the damping factor,which is regarded as a function of CD.In this study,a new relation,combining these above two conventional approaches,is proposed to predict the CD in an operative approach.Results show that values yielded by the new assessment method perform a strong linear relationship with a collection of historical observations,with a promising R2 value of 0.90.Besides,the linear regression derives a new predictive equation for the bulk drag coefficient.Additionally,a calibrated value of 4 for the empirical plant drag coefficient(CP)is revealed.Overall,this new equation,with the superiority of the convenient exponential regression,is expected to be a rapid assessment method for calculating wave attenuation by vegetation and predicting the drag coefficient.
基金the National Natural Science Foundation of China(41877518)the Key Special Program of Logistic Scientific Research of PLA(BLJ18J005)the Key Support Objects of Excellent Talent Pool of Military Medical University。
文摘The potential association between medical resources and the proportion of oldest-old(90 years of age and above)in the Chinese population was examined,and we found that the higher proportion of oldest-old was associated with the higher number of beds in hospitals and health centers.
基金supported by the National Natural Science Foundation of China(NO.31560561)the Inner Mongolia Natural Science Foundation of China(NO.2017ZD05).
文摘Fruit ripening is influenced by multiple plant hormones and the regulation of genes.However,studies on posttranscriptional regulators(e.g.,miRNAs)of fruit growth and ripening are limited.We used miRNA sequencing and degradome methods to identify miRNAs and their target genes in melon(Cucumis melo cv.Hetao melon).A total of 61 conserved miRNAs and 36 novel miRNAs were identified from fruit growth,ripening,climacteric,and postclimacteric developmental stage samples,of which 32 conserved miRNAs were differentially expressed between developmental stage samples.Sixty-two target genes of 43 conserved miRNAs and 1 novel miRNA were identified from degradome sequencing.To further investigate miRNA influencing fruit ripening,transgenic melon plants overexpressing pre-cmemiR393(cme-miR393-OE)were generated and characterized.The results showed that fruit ripening was delayed in cme-miR393-OE transgenic lines compared to nontransgenic fruits.The target of cme-miR393 was also identified,and the expression of CmAFB2 was repressed in transgenic plants.These results provide evidence that miRNA regulates melon fruit ripening and provide potential targets to improve the horticultural traits of melon fruit.
基金supported by the National Natural Science Foundation of China(81571843)the second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0607)the Key Special Program of Logistic Scientific Research of PLA(BLJ18J005)。
文摘Background:When lowlanders rapidly ascend to altitudes>2500 m,they may develop acute mountain sickness(AMS).The individual susceptibility,ascending velocity,time spent at altitude,activity levels and altitude reached are considered risk factors for AMS.However,it is not clear whether sex is a risk factor.The results have been inconclusive.We conducted a meta-analysis to test whether there were sex-based differences in the prevalence of AMS using Lake Louise Scoring System.Methods:Systematic searches were performed in August 2019 in EMBASE,PubMed,and Web of Science for prospective studies with AMS data for men and women.The titles and abstracts were independently checked in the primary screening step,and the selected full-text articles were independently assessed in the secondary screening step by the two authors(YPH and JLW)based on pre-defined inclusion criteria.The meta-analysis was performed using by the STATA 14.1 software program.A random-effects model was employed.Results:Eighteen eligible prospective studies were included.A total of 7669 participants(2639[34.4%]women)were tested.The results showed that there was a statistically significant higher prevalence rate of AMS in women than in men(RR=1.24,95%CI 1.09–1.41),regardless of age or race.However,the heterogeneity was significant in the analysis(Tau2=0.0403,Chi2=50.15,df=17;I2=66.1%,P=0.000),it was main caused by different numbers of subjects among the studies(coefficient=–2.17,P=0.049).Besides,the results showed that there was no evidence of significant publication bias in the combined studies on the basis of Egger’s test(bias coefficient=1.48,P=0.052)and Begg’s test(P=0.130).Conclusions:According to this study,the statistically significant finding emerging from this study was that women have a higher prevalence of AMS.However,the authors could not exclude studies where patients were on acetazolamide.Our analysis provided a direction for future studies of the relationship of sex and the risk of AMS,such as the pathological mechanism and prevention research.
文摘OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/ kg) twice daily for 3 days. RESULTS: IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100or 200 mg/kg) had no significant effect on APTT and PT, but did lengthenTT at a higher dose. CONCLUSION: These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51775147 and 51705105)the Science Challenge Project of China(Grant No.TZ2016006-0503-01)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(Grant No.2018QNRC001)the China Postdoctoral Science Foundation funded project(Grant Nos.2018T110288 and 2017M621260)the Self-Planned Task of State Key Laboratory of Robotics and System(HIT)(Grant Nos.SKLRS201718A and SKLRS201803B).
文摘CO2 laser rapid ablation mitigation(RAM)of fused silica has been used in high-power laser systems owing to its advantages of high efficiency,and ease of implementing batch and automated repairing.In order to study the effect of repaired morphology of RAM on laser modulation and to improve laser damage threshold of optics,an finite element method(FEM)mathematical model of 351 nm laser irradiating fused silica optics is developed based on Maxwell electromagnetic field equations,to explore the 3D near-field light intensity distribution inside optics with repaired site on its surface.The influences of the cone angle and the size of the repaired site on incident laser modulation are studied as well.The results have shown that for the repaired site with a cone angle of 73.3°,the light intensity distribution has obvious three-dimensional characteristics.The relative light intensity on z-section has a circularly distribution,and the radius of the annular intensification zone increases with the decrease of z.While the distribution of maximum relative light intensity on y-section is parabolical with the increase of y.As the cone angle of the repaired site decreases,the effect of the repaired surface on light modulation becomes stronger,leading to a weak resistance to laser damage.Moreover,the large size repaired site would also reduce the laser damage threshold.Therefore,a repaired site with a larger cone angle and smaller size is preferred in practical CO2 laser repairing of surface damage.This work will provide theoretical guidance for the design of repaired surface topography,as well as the improvement of RAM process.
基金supported by the National Natural Science Foundation of China(21567016,21666020)the Natural Science Foundation of Jiangxi Province(20181ACB20005,20171BAB213013,20181BCD40004,20181BAB203017)+2 种基金the Innovation Fund Designated for Graduate Students of Jiangxi Province(YC2018-B015)the Education Department Foundation of Jiangxi Province(KJLD14005)the Opening Fund of Key Laboratory of Process Analysis and Control of Sichuan Universities(2017002)~~
文摘With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impregnation method.By using X-ray diffraction and X-ray photoelectron spectroscopy extrapolation methods,it is disclosed that CuO disperses finely on the SnO2 support to form a monolayer with a capacity of 2.09 mmol 100 m^-2,which equals 4.8 wt%CuO loading.When the CuO loading is below the capacity,it is in a sub-monolayer state.However,when the loading is above the capacity,CuO micro-crystallites will be formed that coexist with the CuO monolayer.The soot combustion activity of the catalyst increases with the CuO loading until it reaches the monolayer dispersion capacity.A further increase in the CuO loading has no evident influence on the activity.Raman results have testified that with the addition of CuO onto the SnO2 support,a surface-active oxygen species can be formed,the amount of which also increases significantly with the increase in the CuO loading until it reaches the monolayer dispersion capacity.Increasing the CuO loading further has no evident impact on the amount of surface oxygen.Therefore,an apparent monolayer dispersion threshold effect is observed for soot combustion over CuO/SnO2 catalysts.It is concluded that the amount of surface-active oxygen sites is the major factor determining the activity of the catalyst.
基金financially supported by the National Natural Science Foundation of China under Grant No.52002254the Sichuan Science and Technology Foundation under Grants No.2020YJ0262,No.2021YFH0127,and No.2022YFH0083+4 种基金the Chunhui Plan of Ministry of EducationFundamental Research Funds for the Central Universities under Grant No.YJ201893the Open-Foundation of Key Laboratory of Laser Device TechnologyChina North Industries Group Corporation Limited under Grant No.KLLDT202104the Open-Foundation of State Key Lab of Advanced Metals and Materials under Grant No.2019-Z03。
文摘Magnetism in two-dimensional(2D)materials has attracted much attention recently.However,intrinsic magnetic 2D materials are rare and mostly unstable in ambient.Although heteroatom doping can introduce magnetism,the basic property especially the electrical-magnetic coupling property has been rarely revealed.Herein,both iron(Fe)-doped and vanadium(V)-doped MoSfilms were grown by chemical vapor deposition.Through studying the structure and electrical property of Fe-doped and V-doped MoS,it was found that both Fe and V doping would decrease the electron concentration,exhibiting a p-type doping effect.Significantly,V-doped MoSdisplays a p-type conduction behavior.Although the carrier mobility decreases after heteroatom doping,both Fe and V doping could endow MoSwith magnetism,in which the transfer curves of both MoStransistors exhibit a strong magneticdependent behavior.It is found that the magnetic response of Fe-doped MoScan be tuned from~0.2 nA/T to~1.3 nA/T,with the tunability much larger than that of V-doped MoS.At last,the magnetic mechanism is discussed with the local magnetic property performed by magnetic force microscopy.The typical morphology-independent magnetic signal demonstrates the formed magnetic domain structure in Fe-doped MoS.This study opens new potential to design novel magnetic-electrical devices.
基金This article was funded by the National Natural Science Foundation of China(Nos.61702270,41971343)the China Postdoctoral Science Foundation(No.2017M621592).
文摘In the last few years,smartphone usage and driver sleepiness have been unanimously considered to lead to numerous road accidents,which causes many scholars to pay attention to autonomous driving.For this complexity scene,one of the major challenges is mining information comprehensively from massive features in vehicle video.This paper proposes a multi-label classification method MCM-VV(Multi-label Classification Method for Vehicle Video)for vehicle video to judge the label of road condition for unmanned system.Method MCM-VV includes a process of feature extraction and a process of multi-label classification.During feature extraction,grayscale,lane line and the edge of main object are extracted after video preprocessing.During the multi-label classification,the algorithm DR-ML-KNN(Multi-label K-nearest Neighbor Classification Algorithm based on Dimensionality Reduction)learns the training set to obtain multi-label classifier,then predicts the label of road condition according to maximum a posteriori principle,finally outputs labels and adds the new instance to training set for the optimization of classifier.Experimental results on five vehicle video datasets show that the method MCM-VV is effective and efficient.The DR-ML-KNN algorithm reduces the runtime by 50%.It also reduces the time complexity and improves the accuracy.
文摘Currently, phosphate based glasses have been potential future biomaterial for medical application due to excellent cytocompatibility and fully bioresorbability. In this study, phosphate based glass system with composition of 48P2O5-12B2O3-(25-X)MgO-14CaO-1Na2O-(X)Fe2O3 (X = 6, 8, 10) and 45P2O5-(Y)B2O3-(32-Y)MgO-14CaO-1Na2O-8Fe2O3 (Y = 12, 15, 20), was prepared via a melting quenching process. The effect of replacing MgO with Fe2O3 and B2O3 on the structural, thermal, degradation properties of phosphate based glass was investigated. Fourier Transform Infrared (FTIR) spectroscopy and Raman spectroscopy analysis confirmed the polymerisation of phosphate based glass network with addition of Fe2O3, thus the processing window was observed to increase whilst the dissolution rate was reduced, attributed to the formation of Fe-O-P cross-link. As the effect on the glass structure stability was demonstrated by both B2O3 and MgO, the nonlinear variation of thermal stability and degradation behaviour was observed for glass system with substitution of MgO by B2O3. However, due to the lower dissolution rate of glass system when compared to the biocompatible phosphate based glass in preliminary study, the expected cytocompatibility could be confirmed in the downstream activities.
基金supported by the National Natural Science Foundation of China(Nos.61702270,41971343,and 61702271)China Postdoctoral Science Foundation(No.2017M621592)China Scholarship Council(No.CSC201906865006)。
文摘According to smoothness assumption,local topological structure can be shared between feature and label manifolds.This study proposes a new algorithm based on Local Tangent Space Alignment(LTSA)to implement the label enhancement process.In general,we first establish a learning model for feature extraction in label space and use a feature extraction method of LTSA to guide the reconstruction of label manifolds.Then,we establish an unconstrained optimization model based on the optimal theory presented in this paper.The model is suitable for solving problems with a large number of sample points.Finally,the experiment results show that the algorithm can effectively improve the training speed and multilabel dataset prediction accuracy.
